diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-08 16:12:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-08 16:12:03 -0700 |
| commit | e1928328699a582a540b105e5f4c160832a7fdcb (patch) | |
| tree | f36bb303b8648189d7b5a7feb27e58fe9fe3b9f0 | |
| parent | 46f1ec23a46940846f86a91c46f7119d8a8b5de1 (diff) | |
| parent | 9156e545765e467e6268c4814cfa609ebb16237e (diff) | |
| download | linux-e1928328699a582a540b105e5f4c160832a7fdcb.tar.bz2 | |
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"The main changes in this cycle are:
- rwsem scalability improvements, phase #2, by Waiman Long, which are
rather impressive:
"On a 2-socket 40-core 80-thread Skylake system with 40 reader
and writer locking threads, the min/mean/max locking operations
done in a 5-second testing window before the patchset were:
40 readers, Iterations Min/Mean/Max = 1,807/1,808/1,810
40 writers, Iterations Min/Mean/Max = 1,807/50,344/151,255
After the patchset, they became:
40 readers, Iterations Min/Mean/Max = 30,057/31,359/32,741
40 writers, Iterations Min/Mean/Max = 94,466/95,845/97,098"
There's a lot of changes to the locking implementation that makes
it similar to qrwlock, including owner handoff for more fair
locking.
Another microbenchmark shows how across the spectrum the
improvements are:
"With a locking microbenchmark running on 5.1 based kernel, the
total locking rates (in kops/s) on a 2-socket Skylake system
with equal numbers of readers and writers (mixed) before and
after this patchset were:
# of Threads Before Patch After Patch
------------ ------------ -----------
2 2,618 4,193
4 1,202 3,726
8 802 3,622
16 729 3,359
32 319 2,826
64 102 2,744"
The changes are extensive and the patch-set has been through
several iterations addressing various locking workloads. There
might be more regressions, but unless they are pathological I
believe we want to use this new implementation as the baseline
going forward.
- jump-label optimizations by Daniel Bristot de Oliveira: the primary
motivation was to remove IPI disturbance of isolated RT-workload
CPUs, which resulted in the implementation of batched jump-label
updates. Beyond the improvement of the real-time characteristics
kernel, in one test this patchset improved static key update
overhead from 57 msecs to just 1.4 msecs - which is a nice speedup
as well.
- atomic64_t cross-arch type cleanups by Mark Rutland: over the last
~10 years of atomic64_t existence the various types used by the
APIs only had to be self-consistent within each architecture -
which means they became wildly inconsistent across architectures.
Mark puts and end to this by reworking all the atomic64
implementations to use 's64' as the base type for atomic64_t, and
to ensure that this type is consistently used for parameters and
return values in the API, avoiding further problems in this area.
- A large set of small improvements to lockdep by Yuyang Du: type
cleanups, output cleanups, function return type and othr cleanups
all around the place.
- A set of percpu ops cleanups and fixes by Peter Zijlstra.
- Misc other changes - please see the Git log for more details"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (82 commits)
locking/lockdep: increase size of counters for lockdep statistics
locking/atomics: Use sed(1) instead of non-standard head(1) option
locking/lockdep: Move mark_lock() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING
x86/jump_label: Make tp_vec_nr static
x86/percpu: Optimize raw_cpu_xchg()
x86/percpu, sched/fair: Avoid local_clock()
x86/percpu, x86/irq: Relax {set,get}_irq_regs()
x86/percpu: Relax smp_processor_id()
x86/percpu: Differentiate this_cpu_{}() and __this_cpu_{}()
locking/rwsem: Guard against making count negative
locking/rwsem: Adaptive disabling of reader optimistic spinning
locking/rwsem: Enable time-based spinning on reader-owned rwsem
locking/rwsem: Make rwsem->owner an atomic_long_t
locking/rwsem: Enable readers spinning on writer
locking/rwsem: Clarify usage of owner's nonspinaable bit
locking/rwsem: Wake up almost all readers in wait queue
locking/rwsem: More optimal RT task handling of null owner
locking/rwsem: Always release wait_lock before waking up tasks
locking/rwsem: Implement lock handoff to prevent lock starvation
locking/rwsem: Make rwsem_spin_on_owner() return owner state
...
55 files changed, 2788 insertions, 2020 deletions
diff --git a/Documentation/atomic_t.txt b/Documentation/atomic_t.txt index b3afe69d03a1..0ab747e0d5ac 100644 --- a/Documentation/atomic_t.txt +++ b/Documentation/atomic_t.txt @@ -81,9 +81,11 @@ Non-RMW ops: The non-RMW ops are (typically) regular LOADs and STOREs and are canonically implemented using READ_ONCE(), WRITE_ONCE(), smp_load_acquire() and -smp_store_release() respectively. +smp_store_release() respectively. Therefore, if you find yourself only using +the Non-RMW operations of atomic_t, you do not in fact need atomic_t at all +and are doing it wrong. -The one detail to this is that atomic_set{}() should be observable to the RMW +A subtle detail of atomic_set{}() is that it should be observable to the RMW ops. That is: C atomic-set @@ -200,6 +202,9 @@ These helper barriers exist because architectures have varying implicit ordering on their SMP atomic primitives. For example our TSO architectures provide full ordered atomics and these barriers are no-ops. +NOTE: when the atomic RmW ops are fully ordered, they should also imply a +compiler barrier. + Thus: atomic_fetch_add(); diff --git a/Documentation/locking/lockdep-design.txt b/Documentation/locking/lockdep-design.txt index 39fae143c9cb..f189d130e543 100644 --- a/Documentation/locking/lockdep-design.txt +++ b/Documentation/locking/lockdep-design.txt @@ -15,34 +15,48 @@ tens of thousands of) instantiations. For example a lock in the inode struct is one class, while each inode has its own instantiation of that lock class. -The validator tracks the 'state' of lock-classes, and it tracks -dependencies between different lock-classes. The validator maintains a -rolling proof that the state and the dependencies are correct. - -Unlike an lock instantiation, the lock-class itself never goes away: when -a lock-class is used for the first time after bootup it gets registered, -and all subsequent uses of that lock-class will be attached to this -lock-class. +The validator tracks the 'usage state' of lock-classes, and it tracks +the dependencies between different lock-classes. Lock usage indicates +how a lock is used with regard to its IRQ contexts, while lock +dependency can be understood as lock order, where L1 -> L2 suggests that +a task is attempting to acquire L2 while holding L1. From lockdep's +perspective, the two locks (L1 and L2) are not necessarily related; that +dependency just means the order ever happened. The validator maintains a +continuing effort to prove lock usages and dependencies are correct or +the validator will shoot a splat if incorrect. + +A lock-class's behavior is constructed by its instances collectively: +when the first instance of a lock-class is used after bootup the class +gets registered, then all (subsequent) instances will be mapped to the +class and hence their usages and dependecies will contribute to those of +the class. A lock-class does not go away when a lock instance does, but +it can be removed if the memory space of the lock class (static or +dynamic) is reclaimed, this happens for example when a module is +unloaded or a workqueue is destroyed. State ----- -The validator tracks lock-class usage history into 4 * nSTATEs + 1 separate -state bits: +The validator tracks lock-class usage history and divides the usage into +(4 usages * n STATEs + 1) categories: +where the 4 usages can be: - 'ever held in STATE context' - 'ever held as readlock in STATE context' - 'ever held with STATE enabled' - 'ever held as readlock with STATE enabled' -Where STATE can be either one of (kernel/locking/lockdep_states.h) - - hardirq - - softirq +where the n STATEs are coded in kernel/locking/lockdep_states.h and as of +now they include: +- hardirq +- softirq +where the last 1 category is: - 'ever used' [ == !unused ] -When locking rules are violated, these state bits are presented in the -locking error messages, inside curlies. A contrived example: +When locking rules are violated, these usage bits are presented in the +locking error messages, inside curlies, with a total of 2 * n STATEs bits. +A contrived example: modprobe/2287 is trying to acquire lock: (&sio_locks[i].lock){-.-.}, at: [<c02867fd>] mutex_lock+0x21/0x24 @@ -51,28 +65,67 @@ locking error messages, inside curlies. A contrived example: (&sio_locks[i].lock){-.-.}, at: [<c02867fd>] mutex_lock+0x21/0x24 -The bit position indicates STATE, STATE-read, for each of the states listed -above, and the character displayed in each indicates: +For a given lock, the bit positions from left to right indicate the usage +of the lock and readlock (if exists), for each of the n STATEs listed +above respectively, and the character displayed at each bit position +indicates: '.' acquired while irqs disabled and not in irq context '-' acquired in irq context '+' acquired with irqs enabled '?' acquired in irq context with irqs enabled. -Unused mutexes cannot be part of the cause of an error. +The bits are illustrated with an example: + + (&sio_locks[i].lock){-.-.}, at: [<c02867fd>] mutex_lock+0x21/0x24 + |||| + ||| \-> softirq disabled and not in softirq context + || \--> acquired in softirq context + | \---> hardirq disabled and not in hardirq context + \----> acquired in hardirq context + + +For a given STATE, whether the lock is ever acquired in that STATE +context and whether that STATE is enabled yields four possible cases as +shown in the table below. The bit character is able to indicate which +exact case is for the lock as of the reporting time. + + ------------------------------------------- + | | irq enabled | irq disabled | + |-------------------------------------------| + | ever in irq | ? | - | + |-------------------------------------------| + | never in irq | + | . | + ------------------------------------------- + +The character '-' suggests irq is disabled because if otherwise the +charactor '?' would have been shown instead. Similar deduction can be +applied for '+' too. + +Unused locks (e.g., mutexes) cannot be part of the cause of an error. Single-lock state rules: ------------------------ +A lock is irq-safe means it was ever used in an irq context, while a lock +is irq-unsafe means it was ever acquired with irq enabled. + A softirq-unsafe lock-class is automatically hardirq-unsafe as well. The -following states are exclusive, and only one of them is allowed to be -set for any lock-class: +following states must be exclusive: only one of them is allowed to be set +for any lock-class based on its usage: + + <hardirq-safe> or <hardirq-unsafe> + <softirq-safe> or <softirq-unsafe> - <hardirq-safe> and <hardirq-unsafe> - <softirq-safe> and <softirq-unsafe> +This is because if a lock can be used in irq context (irq-safe) then it +cannot be ever acquired with irq enabled (irq-unsafe). Otherwise, a +deadlock may happen. For example, in the scenario that after this lock +was acquired but before released, if the context is interrupted this +lock will be attempted to acquire twice, which creates a deadlock, +referred to as lock recursion deadlock. -The validator detects and reports lock usage that violate these +The validator detects and reports lock usage that violates these single-lock state rules. Multi-lock dependency rules: @@ -81,15 +134,18 @@ Multi-lock dependency rules: The same lock-class must not be acquired twice, because this could lead to lock recursion deadlocks. -Furthermore, two locks may not be taken in different order: +Furthermore, two locks can not be taken in inverse order: <L1> -> <L2> <L2> -> <L1> -because this could lead to lock inversion deadlocks. (The validator -finds such dependencies in arbitrary complexity, i.e. there can be any -other locking sequence between the acquire-lock operations, the -validator will still track all dependencies between locks.) +because this could lead to a deadlock - referred to as lock inversion +deadlock - as attempts to acquire the two locks form a circle which +could lead to the two contexts waiting for each other permanently. The +validator will find such dependency circle in arbitrary complexity, +i.e., there can be any other locking sequence between the acquire-lock +operations; the validator will still find whether these locks can be +acquired in a circular fashion. Furthermore, the following usage based lock dependencies are not allowed between any two lock-classes: diff --git a/arch/alpha/include/asm/atomic.h b/arch/alpha/include/asm/atomic.h index 150a1c5d6a2c..2144530d1428 100644 --- a/arch/alpha/include/asm/atomic.h +++ b/arch/alpha/include/asm/atomic.h @@ -93,9 +93,9 @@ static inline int atomic_fetch_##op##_relaxed(int i, atomic_t *v) \ } #define ATOMIC64_OP(op, asm_op) \ -static __inline__ void atomic64_##op(long i, atomic64_t * v) \ +static __inline__ void atomic64_##op(s64 i, atomic64_t * v) \ { \ - unsigned long temp; \ + s64 temp; \ __asm__ __volatile__( \ "1: ldq_l %0,%1\n" \ " " #asm_op " %0,%2,%0\n" \ @@ -109,9 +109,9 @@ static __inline__ void atomic64_##op(long i, atomic64_t * v) \ } \ #define ATOMIC64_OP_RETURN(op, asm_op) \ -static __inline__ long atomic64_##op##_return_relaxed(long i, atomic64_t * v) \ +static __inline__ s64 atomic64_##op##_return_relaxed(s64 i, atomic64_t * v) \ { \ - long temp, result; \ + s64 temp, result; \ __asm__ __volatile__( \ "1: ldq_l %0,%1\n" \ " " #asm_op " %0,%3,%2\n" \ @@ -128,9 +128,9 @@ static __inline__ long atomic64_##op##_return_relaxed(long i, atomic64_t * v) \ } #define ATOMIC64_FETCH_OP(op, asm_op) \ -static __inline__ long atomic64_fetch_##op##_relaxed(long i, atomic64_t * v) \ +static __inline__ s64 atomic64_fetch_##op##_relaxed(s64 i, atomic64_t * v) \ { \ - long temp, result; \ + s64 temp, result; \ __asm__ __volatile__( \ "1: ldq_l %2,%1\n" \ " " #asm_op " %2,%3,%0\n" \ @@ -246,9 +246,9 @@ static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u) * Atomically adds @a to @v, so long as it was not @u. * Returns the old value of @v. */ -static __inline__ long atomic64_fetch_add_unless(atomic64_t *v, long a, long u) +static __inline__ s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u) { - long c, new, old; + s64 c, new, old; smp_mb(); __asm__ __volatile__( "1: ldq_l %[old],%[mem]\n" @@ -276,9 +276,9 @@ static __inline__ long atomic64_fetch_add_unless(atomic64_t *v, long a, long u) * The function returns the old value of *v minus 1, even if * the atomic variable, v, was not decremented. */ -static inline long atomic64_dec_if_positive(atomic64_t *v) +static inline s64 atomic64_dec_if_positive(atomic64_t *v) { - long old, tmp; + s64 old, tmp; smp_mb(); __asm__ __volatile__( "1: ldq_l %[old],%[mem]\n" diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h index 17cf1c657cb3..7298ce84762e 100644 --- a/arch/arc/include/asm/atomic.h +++ b/arch/arc/include/asm/atomic.h @@ -321,14 +321,14 @@ ATOMIC_OPS(xor, ^=, CTOP_INST_AXOR_DI_R2_R2_R3) */ typedef struct { - aligned_u64 counter; + s64 __aligned(8) counter; } atomic64_t; #define ATOMIC64_INIT(a) { (a) } -static inline long long atomic64_read(const atomic64_t *v) +static inline s64 atomic64_read(const atomic64_t *v) { - unsigned long long val; + s64 val; __asm__ __volatile__( " ldd %0, [%1] \n" @@ -338,7 +338,7 @@ static inline long long atomic64_read(const atomic64_t *v) return val; } -static inline void atomic64_set(atomic64_t *v, long long a) +static inline void atomic64_set(atomic64_t *v, s64 a) { /* * This could have been a simple assignment in "C" but would need @@ -359,9 +359,9 @@ static inline void atomic64_set(atomic64_t *v, long long a) } #define ATOMIC64_OP(op, op1, op2) \ -static inline void atomic64_##op(long long a, atomic64_t *v) \ +static inline void atomic64_##op(s64 a, atomic64_t *v) \ { \ - unsigned long long val; \ + s64 val; \ \ __asm__ __volatile__( \ "1: \n" \ @@ -372,13 +372,13 @@ static inline void atomic64_##op(long long a, atomic64_t *v) \ " bnz 1b \n" \ : "=&r"(val) \ : "r"(&v->counter), "ir"(a) \ - : "cc"); \ + : "cc"); \ } \ #define ATOMIC64_OP_RETURN(op, op1, op2) \ -static inline long long atomic64_##op##_return(long long a, atomic64_t *v) \ +static inline s64 atomic64_##op##_return(s64 a, atomic64_t *v) \ { \ - unsigned long long val; \ + s64 val; \ \ smp_mb(); \ \ @@ -399,9 +399,9 @@ static inline long long atomic64_##op##_return(long long a, atomic64_t *v) \ } #define ATOMIC64_FETCH_OP(op, op1, op2) \ -static inline long long atomic64_fetch_##op(long long a, atomic64_t *v) \ +static inline s64 atomic64_fetch_##op(s64 a, atomic64_t *v) \ { \ - unsigned long long val, orig; \ + s64 val, orig; \ \ smp_mb(); \ \ @@ -441,10 +441,10 @@ ATOMIC64_OPS(xor, xor, xor) #undef ATOMIC64_OP_RETURN #undef ATOMIC64_OP -static inline long long -atomic64_cmpxchg(atomic64_t *ptr, long long expected, long long new) +static inline s64 +atomic64_cmpxchg(atomic64_t *ptr, s64 expected, s64 new) { - long long prev; + s64 prev; smp_mb(); @@ -464,9 +464,9 @@ atomic64_cmpxchg(atomic64_t *ptr, long long expected, long long new) return prev; } -static inline long long atomic64_xchg(atomic64_t *ptr, long long new) +static inline s64 atomic64_xchg(atomic64_t *ptr, s64 new) { - long long prev; + s64 prev; smp_mb(); @@ -492,9 +492,9 @@ static inline long long atomic64_xchg(atomic64_t *ptr, long long new) * the atomic variable, v, was not decremented. */ -static inline long long atomic64_dec_if_positive(atomic64_t *v) +static inline s64 atomic64_dec_if_positive(atomic64_t *v) { - long long val; + s64 val; smp_mb(); @@ -525,10 +525,9 @@ static inline long long atomic64_dec_if_positive(atomic64_t *v) * Atomically adds @a to @v, if it was not @u. * Returns the old value of @v */ -static inline long long atomic64_fetch_add_unless(atomic64_t *v, long long a, - long long u) +static inline s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u) { - long long old, temp; + s64 old, temp; smp_mb(); diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h index 50c3ac5f0809..75bb2c543e59 100644 --- a/arch/arm/include/asm/atomic.h +++ b/arch/arm/include/asm/atomic.h @@ -246,15 +246,15 @@ ATOMIC_OPS(xor, ^=, eor) #ifndef CONFIG_GENERIC_ATOMIC64 typedef struct { - long long counter; + s64 counter; } atomic64_t; #define ATOMIC64_INIT(i) { (i) } #ifdef CONFIG_ARM_LPAE -static inline long long atomic64_read(const atomic64_t *v) +static inline s64 atomic64_read(const atomic64_t *v) { - long long result; + s64 result; __asm__ __volatile__("@ atomic64_read\n" " ldrd %0, %H0, [%1]" @@ -265,7 +265,7 @@ static inline long long atomic64_read(const atomic64_t *v) return result; } -static inline void atomic64_set(atomic64_t *v, long long i) +static inline void atomic64_set(atomic64_t *v, s64 i) { __asm__ __volatile__("@ atomic64_set\n" " strd %2, %H2, [%1]" @@ -274,9 +274,9 @@ static inline void atomic64_set(atomic64_t *v, long long i) ); } #else -static inline long long atomic64_read(const atomic64_t *v) +static inline s64 atomic64_read(const atomic64_t *v) { - long long result; + s64 result; __asm__ __volatile__("@ atomic64_read\n" " ldrexd %0, %H0, [%1]" @@ -287,9 +287,9 @@ static inline long long atomic64_read(const atomic64_t *v) return result; } -static inline void atomic64_set(atomic64_t *v, long long i) +static inline void atomic64_set(atomic64_t *v, s64 i) { - long long tmp; + s64 tmp; prefetchw(&v->counter); __asm__ __volatile__("@ atomic64_set\n" @@ -304,9 +304,9 @@ static inline void atomic64_set(atomic64_t *v, long long i) #endif #define ATOMIC64_OP(op, op1, op2) \ -static inline void atomic64_##op(long long i, atomic64_t *v) \ +static inline void atomic64_##op(s64 i, atomic64_t *v) \ { \ - long long result; \ + s64 result; \ unsigned long tmp; \ \ prefetchw(&v->counter); \ @@ -323,10 +323,10 @@ static inline void atomic64_##op(long long i, atomic64_t *v) \ } \ #define ATOMIC64_OP_RETURN(op, op1, op2) \ -static inline long long \ -atomic64_##op##_return_relaxed(long long i, atomic64_t *v) \ +static inline s64 \ +atomic64_##op##_return_relaxed(s64 i, atomic64_t *v) \ { \ - long long result; \ + s64 result; \ unsigned long tmp; \ \ prefetchw(&v->counter); \ @@ -346,10 +346,10 @@ atomic64_##op##_return_relaxed(long long i, atomic64_t *v) \ } #define ATOMIC64_FETCH_OP(op, op1, op2) \ -static inline long long \ -atomic64_fetch_##op##_relaxed(long long i, atomic64_t *v) \ +static inline s64 \ +atomic64_fetch_##op##_relaxed(s64 i, atomic64_t *v) \ { \ - long long result, val; \ + s64 result, val; \ unsigned long tmp; \ \ prefetchw(&v->counter); \ @@ -403,10 +403,9 @@ ATOMIC64_OPS(xor, eor, eor) #undef ATOMIC64_OP_RETURN #undef ATOMIC64_OP -static inline long long -atomic64_cmpxchg_relaxed(atomic64_t *ptr, long long old, long long new) +static inline s64 atomic64_cmpxchg_relaxed(atomic64_t *ptr, s64 old, s64 new) { - long long oldval; + s64 oldval; unsigned long res; prefetchw(&ptr->counter); @@ -427,9 +426,9 @@ atomic64_cmpxchg_relaxed(atomic64_t *ptr, long long old, long long new) } #define atomic64_cmpxchg_relaxed atomic64_cmpxchg_relaxed -static inline long long atomic64_xchg_relaxed(atomic64_t *ptr, long long new) +static inline s64 atomic64_xchg_relaxed(atomic64_t *ptr, s64 new) { - long long result; + s64 result; unsigned long tmp; prefetchw(&ptr->counter); @@ -447,9 +446,9 @@ static inline long long atomic64_xchg_relaxed(atomic64_t *ptr, long long new) } #define atomic64_xchg_relaxed atomic64_xchg_relaxed -static inline long long atomic64_dec_if_positive(atomic64_t *v) +static inline s64 atomic64_dec_if_positive(atomic64_t *v) { - long long result; + s64 result; unsigned long tmp; smp_mb(); @@ -475,10 +474,9 @@ static inline long long atomic64_dec_if_positive(atomic64_t *v) } #define atomic64_dec_if_positive atomic64_dec_if_positive -static inline long long atomic64_fetch_add_unless(atomic64_t *v, long long a, - long long u) +static inline s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u) { - long long oldval, newval; + s64 oldval, newval; unsigned long tmp; smp_mb(); diff --git a/arch/arm64/include/asm/atomic_ll_sc.h b/arch/arm64/include/asm/atomic_ll_sc.h index 23c378606aed..c8c850bc3dfb 100644 --- a/arch/arm64/include/asm/atomic_ll_sc.h +++ b/arch/arm64/include/asm/atomic_ll_sc.h @@ -122,9 +122,9 @@ ATOMIC_OPS(xor, eor) #define ATOMIC64_OP(op, asm_op) \ __LL_SC_INLINE void \ -__LL_SC_PREFIX(arch_atomic64_##op(long i, atomic64_t *v)) \ +__LL_SC_PREFIX(arch_atomic64_##op(s64 i, atomic64_t *v)) \ { \ - long result; \ + s64 result; \ unsigned long tmp; \ \ asm volatile("// atomic64_" #op "\n" \ @@ -139,10 +139,10 @@ __LL_SC_PREFIX(arch_atomic64_##op(long i, atomic64_t *v)) \ __LL_SC_EXPORT(arch_atomic64_##op); #define ATOMIC64_OP_RETURN(name, mb, acq, rel, cl, op, asm_op) \ -__LL_SC_INLINE long \ -__LL_SC_PREFIX(arch_atomic64_##op##_return##name(long i, atomic64_t *v))\ +__LL_SC_INLINE s64 \ +__LL_SC_PREFIX(arch_atomic64_##op##_return##name(s64 i, atomic64_t *v))\ { \ - long result; \ + s64 result; \ unsigned long tmp; \ \ asm volatile("// atomic64_" #op "_return" #name "\n" \ @@ -161,10 +161,10 @@ __LL_SC_PREFIX(arch_atomic64_##op##_return##name(long i, atomic64_t *v))\ __LL_SC_EXPORT(arch_atomic64_##op##_return##name); #define ATOMIC64_FETCH_OP(name, mb, acq, rel, cl, op, asm_op) \ -__LL_SC_INLINE long \ -__LL_SC_PREFIX(arch_atomic64_fetch_##op##name(long i, atomic64_t *v)) \ +__LL_SC_INLINE s64 \ +__LL_SC_PREFIX(arch_atomic64_fetch_##op##name(s64 i, atomic64_t *v)) \ { \ - long result, val; \ + s64 result, val; \ unsigned long tmp; \ \ asm volatile("// atomic64_fetch_" #op #name "\n" \ @@ -214,10 +214,10 @@ ATOMIC64_OPS(xor, eor) #undef ATOMIC64_OP_RETURN #undef ATOMIC64_OP -__LL_SC_INLINE long +__LL_SC_INLINE s64 __LL_SC_PREFIX(arch_atomic64_dec_if_positive(atomic64_t *v)) { - long result; + s64 result; unsigned long tmp; asm volatile("// atomic64_dec_if_positive\n" diff --git a/arch/arm64/include/asm/atomic_lse.h b/arch/arm64/include/asm/atomic_lse.h index 45e030d54332..69acb1c19a15 100644 --- a/arch/arm64/include/asm/atomic_lse.h +++ b/arch/arm64/include/asm/atomic_lse.h @@ -213,9 +213,9 @@ ATOMIC_FETCH_OP_SUB( , al, "memory") #define __LL_SC_ATOMIC64(op) __LL_SC_CALL(arch_atomic64_##op) #define ATOMIC64_OP(op, asm_op) \ -static inline void arch_atomic64_##op(long i, atomic64_t *v) \ +static inline void arch_atomic64_##op(s64 i, atomic64_t *v) \ { \ - register long x0 asm ("x0") = i; \ + register s64 x0 asm ("x0") = i; \ register atomic64_t *x1 asm ("x1") = v; \ \ asm volatile(ARM64_LSE_ATOMIC_INSN(__LL_SC_ATOMIC64(op), \ @@ -233,9 +233,9 @@ ATOMIC64_OP(add, stadd) #undef ATOMIC64_OP #define ATOMIC64_FETCH_OP(name, mb, op, asm_op, cl...) \ -static inline long arch_atomic64_fetch_##op##name(long i, atomic64_t *v)\ +static inline s64 arch_atomic64_fetch_##op##name(s64 i, atomic64_t *v) \ { \ - register long x0 asm ("x0") = i; \ + register s64 x0 asm ("x0") = i; \ register atomic64_t *x1 asm ("x1") = v; \ \ asm volatile(ARM64_LSE_ATOMIC_INSN( \ @@ -265,9 +265,9 @@ ATOMIC64_FETCH_OPS(add, ldadd) #undef ATOMIC64_FETCH_OPS #define ATOMIC64_OP_ADD_RETURN(name, mb, cl...) \ -static inline long arch_atomic64_add_return##name(long i, atomic64_t *v)\ +static inline s64 arch_atomic64_add_return##name(s64 i, atomic64_t *v) \ { \ - register long x0 asm ("x0") = i; \ + register s64 x0 asm ("x0") = i; \ register atomic64_t *x1 asm ("x1") = v; \ \ asm volatile(ARM64_LSE_ATOMIC_INSN( \ @@ -291,9 +291,9 @@ ATOMIC64_OP_ADD_RETURN( , al, "memory") #undef ATOMIC64_OP_ADD_RETURN -static inline void arch_atomic64_and(long i, atomic64_t *v) +static inline void arch_atomic64_and(s64 i, atomic64_t *v) { - register long x0 asm ("x0") = i; + register s64 x0 asm ("x0") = i; register atomic64_t *x1 asm ("x1") = v; asm volatile(ARM64_LSE_ATOMIC_INSN( @@ -309,9 +309,9 @@ static inline void arch_atomic64_and(long i, atomic64_t *v) } #define ATOMIC64_FETCH_OP_AND(name, mb, cl...) \ -static inline long arch_atomic64_fetch_and##name(long i, atomic64_t *v) \ +static inline s64 arch_atomic64_fetch_and##name(s64 i, atomic64_t *v) \ { \ - register long x0 asm ("x0") = i; \ + register s64 x0 asm ("x0") = i; \ register atomic64_t *x1 asm ("x1") = v; \ \ asm volatile(ARM64_LSE_ATOMIC_INSN( \ @@ -335,9 +335,9 @@ ATOMIC64_FETCH_OP_AND( , al, "memory") #undef ATOMIC64_FETCH_OP_AND -static inline void arch_atomic64_sub(long i, atomic64_t *v) +static inline void arch_atomic64_sub(s64 i, atomic64_t *v) { - register long x0 asm ("x0") = i; + register s64 x0 asm ("x0") = i; register atomic64_t *x1 asm ("x1") = v; asm volatile(ARM64_LSE_ATOMIC_INSN( @@ -353,9 +353,9 @@ static inline void arch_atomic64_sub(long i, atomic64_t *v) } #define ATOMIC64_OP_SUB_RETURN(name, mb, cl...) \ -static inline long arch_atomic64_sub_return##name(long i, atomic64_t *v)\ +static inline s64 arch_atomic64_sub_return##name(s64 i, atomic64_t *v) \ { \ - register long x0 asm ("x0") = i; \ + register s64 x0 asm ("x0") = i; \ register atomic64_t *x1 asm ("x1") = v; \ \ asm volatile(ARM64_LSE_ATOMIC_INSN( \ @@ -381,9 +381,9 @@ ATOMIC64_OP_SUB_RETURN( , al, "memory") #undef ATOMIC64_OP_SUB_RETURN #define ATOMIC64_FETCH_OP_SUB(name, mb, cl...) \ -static inline long arch_atomic64_fetch_sub##name(long i, atomic64_t *v) \ +static inline s64 arch_atomic64_fetch_sub##name(s64 i, atomic64_t *v) \ { \ - register long x0 asm ("x0") = i; \ + register s64 x0 asm ("x0") = i; \ register atomic64_t *x1 asm ("x1") = v; \ \ asm volatile(ARM64_LSE_ATOMIC_INSN( \ @@ -407,7 +407,7 @@ ATOMIC64_FETCH_OP_SUB( , al, "memory") #undef ATOMIC64_FETCH_OP_SUB -static inline long arch_atomic64_dec_if_positive(atomic64_t *v) +static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v) { register long x0 asm ("x0") = (long)v; diff --git a/arch/ia64/include/asm/atomic.h b/arch/ia64/include/asm/atomic.h index 206530d0751b..50440f3ddc43 100644 --- a/arch/ia64/include/asm/atomic.h +++ b/arch/ia64/include/asm/atomic.h @@ -124,10 +124,10 @@ ATOMIC_FETCH_OP(xor, ^) #undef ATOMIC_OP #define ATOMIC64_OP(op, c_op) \ -static __inline__ long \ -ia64_atomic64_##op (__s64 i, atomic64_t *v) \ +static __inline__ s64 \ +ia64_atomic64_##op (s64 i, atomic64_t *v) \ { \ - __s64 old, new; \ + s64 old, new; \ CMPXCHG_BUGCHECK_DECL \ \ do { \ @@ -139,10 +139,10 @@ ia64_atomic64_##op (__s64 i, atomic64_t *v) \ } #define ATOMIC64_FETCH_OP(op, c_op) \ -static __inline__ long \ -ia64_atomic64_fetch_##op (__s64 i, atomic64_t *v) \ +static __inline__ s64 \ +ia64_atomic64_fetch_##op (s64 i, atomic64_t *v) \ { \ - __s64 old, new; \ + s64 old, new; \ CMPXCHG_BUGCHECK_DECL \ \ do { \ @@ -162,7 +162,7 @@ ATOMIC64_OPS(sub, -) #define atomic64_add_return(i,v) \ ({ \ - long __ia64_aar_i = (i); \ + s64 __ia64_aar_i = (i); \ __ia64_atomic_const(i) \ ? ia64_fetch_and_add(__ia64_aar_i, &(v)->counter) \ : ia64_atomic64_add(__ia64_aar_i, v); \ @@ -170,7 +170,7 @@ ATOMIC64_OPS(sub, -) #define atomic64_sub_return(i,v) \ ({ \ - long __ia64_asr_i = (i); \ + s64 __ia64_asr_i = (i); \ __ia64_atomic_const(i) \ ? ia64_fetch_and_add(-__ia64_asr_i, &(v)->counter) \ : ia64_atomic64_sub(__ia64_asr_i, v); \ @@ -178,7 +178,7 @@ ATOMIC64_OPS(sub, -) #define atomic64_fetch_add(i,v) \ ({ \ - long __ia64_aar_i = (i); \ + s64 __ia64_aar_i = (i); \ __ia64_atomic_const(i) \ ? ia64_fetchadd(__ia64_aar_i, &(v)->counter, acq) \ : ia64_atomic64_fetch_add(__ia64_aar_i, v); \ @@ -186,7 +186,7 @@ ATOMIC64_OPS(sub, -) #define atomic64_fetch_sub(i,v) \ ({ \ - long __ia64_asr_i = (i); \ + s64 __ia64_asr_i = (i); \ __ia64_atomic_const(i) \ ? ia64_fetchadd(-__ia64_asr_i, &(v)->counter, acq) \ : ia64_atomic64_fetch_sub(__ia64_asr_i, v); \ diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h index 94096299fc56..9a82dd11c0e9 100644 --- a/arch/mips/include/asm/atomic.h +++ b/arch/mips/include/asm/atomic.h @@ -254,10 +254,10 @@ static __inline__ int atomic_sub_if_positive(int i, atomic_t * v) #define atomic64_set(v, i) WRITE_ONCE((v)->counter, (i)) #define ATOMIC64_OP(op, c_op, asm_op) \ -static __inline__ void atomic64_##op(long i, atomic64_t * v) \ +static __inline__ void atomic64_##op(s64 i, atomic64_t * v) \ { \ if (kernel_uses_llsc) { \ - long temp; \ + s64 temp; \ \ loongson_llsc_mb(); \ __asm__ __volatile__( \ @@ -280,12 +280,12 @@ static __inline__ void atomic64_##op(long i, atomic64_t * v) \ } #define ATOMIC64_OP_RETURN(op, c_op, asm_op) \ -static __inline__ long atomic64_##op##_return_relaxed(long i, atomic64_t * v) \ +static __inline__ s64 atomic64_##op##_return_relaxed(s64 i, atomic64_t * v) \ { \ - long result; \ + s64 result; \ \ if (kernel_uses_llsc) { \ - long temp; \ + s64 temp; \ \ loongson_llsc_mb(); \ __asm__ __volatile__( \ @@ -314,12 +314,12 @@ static __inline__ long atomic64_##op##_return_relaxed(long i, atomic64_t * v) \ } #define ATOMIC64_FETCH_OP(op, c_op, asm_op) \ -static __inline__ long atomic64_fetch_##op##_relaxed(long i, atomic64_t * v) \ +static __inline__ s64 atomic64_fetch_##op##_relaxed(s64 i, atomic64_t * v) \ { \ - long result; \ + s64 result; \ \ if (kernel_uses_llsc) { \ - long temp; \ + s64 temp; \ \ loongson_llsc_mb(); \ __asm__ __volatile__( \ @@ -386,14 +386,14 @@ ATOMIC64_OPS(xor, ^=, xor) * Atomically test @v and subtract @i if @v is greater or equal than @i. * The function returns the old value of @v minus @i. */ -static __inline__ long atomic64_sub_if_positive(long i, atomic64_t * v) +static __inline__ s64 atomic64_sub_if_positive(s64 i, atomic64_t * v) { - long result; + s64 result; smp_mb__before_llsc(); if (kernel_uses_llsc) { - long temp; + s64 temp; __asm__ __volatile__( " .set push \n" diff --git a/arch/powerpc/include/asm/atomic.h b/arch/powerpc/include/asm/atomic.h index 52eafaf74054..31c231ea56b7 100644 --- a/arch/powerpc/include/asm/atomic.h +++ b/arch/powerpc/include/asm/atomic.h @@ -297,24 +297,24 @@ static __inline__ int atomic_dec_if_positive(atomic_t *v) #define ATOMIC64_INIT(i) { (i) } -static __inline__ long atomic64_read(const atomic64_t *v) +static __inline__ s64 atomic64_read(const atomic64_t *v) { - long t; + s64 t; __asm__ __volatile__("ld%U1%X1 %0,%1" : "=r"(t) : "m"(v->counter)); return t; } -static __inline__ void atomic64_set(atomic64_t *v, long i) +static __inline__ void atomic64_set(atomic64_t *v, s64 i) { __asm__ __volatile__("std%U0%X0 %1,%0" : "=m"(v->counter) : "r"(i)); } #define ATOMIC64_OP(op, asm_op) \ -static __inline__ void atomic64_##op(long a, atomic64_t *v) \ +static __inline__ void atomic64_##op(s64 a, atomic64_t *v) \ { \ - long t; \ + s64 t; \ \ __asm__ __volatile__( \ "1: ldarx %0,0,%3 # atomic64_" #op "\n" \ @@ -327,10 +327,10 @@ static __inline__ void atomic64_##op(long a, atomic64_t *v) \ } #define ATOMIC64_OP_RETURN_RELAXED(op, asm_op) \ -static inline long \ -atomic64_##op##_return_relaxed(long a, atomic64_t *v) \ +static inline s64 \ +atomic64_##op##_return_relaxed(s64 a, atomic64_t *v) \ { \ - long t; \ + s64 t; \ \ __asm__ __volatile__( \ "1: ldarx %0,0,%3 # atomic64_" #op "_return_relaxed\n" \ @@ -345,10 +345,10 @@ atomic64_##op##_return_relaxed(long a, atomic64_t *v) \ } #define ATOMIC64_FETCH_OP_RELAXED(op, asm_op) \ -static inline long \ -atomic64_fetch_##op##_relaxed(long a, atomic64_t *v) \ +static inline s64 \ +atomic64_fetch_##op##_relaxed(s64 a, atomic64_t *v) \ { \ - long res, t; \ + s64 res, t; \ \ __asm__ __volatile__( \ "1: ldarx %0,0,%4 # atomic64_fetch_" #op "_relaxed\n" \ @@ -396,7 +396,7 @@ ATOMIC64_OPS(xor, xor) static __inline__ void atomic64_inc(atomic64_t *v) { - long t; + s64 t; __asm__ __volatile__( "1: ldarx %0,0,%2 # atomic64_inc\n\ @@ -409,9 +409,9 @@ static __inline__ void atomic64_inc(atomic64_t *v) } #define atomic64_inc atomic64_inc -static __inline__ long atomic64_inc_return_relaxed(atomic64_t *v) +static __inline__ s64 atomic64_inc_return_relaxed(atomic64_t *v) { - long t; + s64 t; __asm__ __volatile__( "1: ldarx %0,0,%2 # atomic64_inc_return_relaxed\n" @@ -427,7 +427,7 @@ static __inline__ long atomic64_inc_return_relaxed(atomic64_t *v) static __inline__ void atomic64_dec(atomic64_t *v) { - long t; + s64 t; __asm__ __volatile__( "1: ldarx %0,0,%2 # atomic64_dec\n\ @@ -440,9 +440,9 @@ static __inline__ void atomic64_dec(atomic64_t *v) } #define atomic64_dec atomic64_dec -static __inline__ long atomic64_dec_return_relaxed(atomic64_t *v) +static __inline__ s64 atomic64_dec_return_relaxed(atomic64_t *v) { - long t; + s64 t; __asm__ __volatile__( "1: ldarx %0,0,%2 # atomic64_dec_return_relaxed\n" @@ -463,9 +463,9 @@ static __inline__ long atomic64_dec_return_relaxed(atomic64_t *v) * Atomically test *v and decrement if it is greater than 0. * The function returns the old value of *v minus 1. */ -static __inline__ long atomic64_dec_if_positive(atomic64_t *v) +static __inline__ s64 atomic64_dec_if_positive(atomic64_t *v) { - long t; + s64 t; __asm__ __volatile__( PPC_ATOMIC_ENTRY_BARRIER @@ -502,9 +502,9 @@ static __inline__ long atomic64_dec_if_positive(atomic64_t *v) * Atomically adds @a to @v, so long as it was not @u. * Returns the old value of @v. */ -static __inline__ long atomic64_fetch_add_unless(atomic64_t *v, long a, long u) +static __inline__ s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u) { - long t; + s64 t; __asm__ __volatile__ ( PPC_ATOMIC_ENTRY_BARRIER @@ -534,7 +534,7 @@ static __inline__ long atomic64_fetch_add_unless(atomic64_t *v, long a, long u) */ static __inline__ int atomic64_inc_not_zero(atomic64_t *v) { - long t1, t2; + s64 t1, t2; __asm__ __volatile__ ( PPC_ATOMIC_ENTRY_BARRIER diff --git a/arch/riscv/include/asm/atomic.h b/arch/riscv/include/asm/atomic.h index 9038aeb900a6..96f95c9ebd97 100644 --- a/arch/riscv/include/asm/atomic.h +++ b/arch/riscv/include/asm/atomic.h @@ -38,11 +38,11 @@ static __always_inline void atomic_set(atomic_t *v, int i) #ifndef CONFIG_GENERIC_ATOMIC64 #define ATOMIC64_INIT(i) { (i) } -static __always_inline long atomic64_read(const atomic64_t *v) +static __always_inline s64 atomic64_read(const atomic64_t *v) { return READ_ONCE(v->counter); } -static __always_inline void atomic64_set(atomic64_t *v, long i) +static __always_inline void atomic64_set(atomic64_t *v, s64 i) { WRITE_ONCE(v->counter, i); } @@ -66,11 +66,11 @@ void atomic##prefix##_##op(c_type i, atomic##prefix##_t *v) \ #ifdef CONFIG_GENERIC_ATOMIC64 #define ATOMIC_OPS(op, asm_op, I) \ - ATOMIC_OP (op, asm_op, I, w, int, ) + ATOMIC_OP (op, asm_op, I, w, int, ) #else #define ATOMIC_OPS(op, asm_op, I) \ - ATOMIC_OP (op, asm_op, I, w, int, ) \ - ATOMIC_OP (op, asm_op, I, d, long, 64) + ATOMIC_OP (op, asm_op, I, w, int, ) \ + ATOMIC_OP (op, asm_op, I, d, s64, 64) #endif ATOMIC_OPS(add, add, i) @@ -127,14 +127,14 @@ c_type atomic##prefix##_##op##_return(c_type i, atomic##prefix##_t *v) \ #ifdef CONFIG_GENERIC_ATOMIC64 #define ATOMIC_OPS(op, asm_op, c_op, I) \ - ATOMIC_FETCH_OP( op, asm_op, I, w, int, ) \ - ATOMIC_OP_RETURN(op, asm_op, c_op, I, w, int, ) + ATOMIC_FETCH_OP( op, asm_op, I, w, int, ) \ + ATOMIC_OP_RETURN(op, asm_op, c_op, I, w, int, ) #else #define ATOMIC_OPS(op, asm_op, c_op, I) \ - ATOMIC_FETCH_OP( op, asm_op, I, w, int, ) \ - ATOMIC_OP_RETURN(op, asm_op, c_op, I, w, int, ) \ - ATOMIC_FETCH_OP( op, asm_op, I, d, long, 64) \ - ATOMIC_OP_RETURN(op, asm_op, c_op, I, d, long, 64) + ATOMIC_FETCH_OP( op, asm_op, I, w, int, ) \ + ATOMIC_OP_RETURN(op, asm_op, c_op, I, w, int, ) \ + ATOMIC_FETCH_OP( op, asm_op, I, d, s64, 64) \ + ATOMIC_OP_RETURN(op, asm_op, c_op, I, d, s64, 64) #endif ATOMIC_OPS(add, add, +, i) @@ -166,11 +166,11 @@ ATOMIC_OPS(sub, add, +, -i) #ifdef CONFIG_GENERIC_ATOMIC64 #define ATOMIC_OPS(op, asm_op, I) \ - ATOMIC_FETCH_OP(op, asm_op, I, w, int, ) + ATOMIC_FETCH_OP(op, asm_op, I, w, int, ) #else #define ATOMIC_OPS(op, asm_op, I) \ - ATOMIC_FETCH_OP(op, asm_op, I, w, int, ) \ - ATOMIC_FETCH_OP(op, asm_op, I, d, long, 64) + ATOMIC_FETCH_OP(op, asm_op, I, w, int, ) \ + ATOMIC_FETCH_OP(op, asm_op, I, d, s64, 64) #endif ATOMIC_OPS(and, and, i) @@ -219,9 +219,10 @@ static __always_inline int atomic_fetch_add_unless(atomic_t *v, int a, int u) #define atomic_fetch_add_unless atomic_fetch_add_unless #ifndef CONFIG_GENERIC_ATOMIC64 -static __always_inline long atomic64_fetch_add_unless(atomic64_t *v, long a, long u) +static __always_inline s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u) { - long prev, rc; + s64 prev; + long rc; __asm__ __volatile__ ( "0: lr.d %[p], %[c]\n" @@ -290,11 +291,11 @@ c_t atomic##prefix##_cmpxchg(atomic##prefix##_t *v, c_t o, c_t n) \ #ifdef CONFIG_GENERIC_ATOMIC64 #define ATOMIC_OPS() \ - ATOMIC_OP( int, , 4) + ATOMIC_OP(int, , 4) #else #define ATOMIC_OPS() \ - ATOMIC_OP( int, , 4) \ - ATOMIC_OP(long, 64, 8) + ATOMIC_OP(int, , 4) \ + ATOMIC_OP(s64, 64, 8) #endif ATOMIC_OPS() @@ -332,9 +333,10 @@ static __always_inline int atomic_sub_if_positive(atomic_t *v, int offset) #define atomic_dec_if_positive(v) atomic_sub_if_positive(v, 1) #ifndef CONFIG_GENERIC_ATOMIC64 -static __always_inline long atomic64_sub_if_positive(atomic64_t *v, int offset) +static __always_inline s64 atomic64_sub_if_positive(atomic64_t *v, s64 offset) { - long prev, rc; + s64 prev; + long rc; __asm__ __volatile__ ( "0: lr.d %[p], %[c]\n" diff --git a/arch/s390/include/asm/atomic.h b/arch/s390/include/asm/atomic.h index fd20ab5d4cf7..491ad53a0d4e 100644 --- a/arch/s390/include/asm/atomic.h +++ b/arch/s390/include/asm/atomic.h @@ -84,9 +84,9 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, int new) #define ATOMIC64_INIT(i) { (i) } -static inline long atomic64_read(const atomic64_t *v) +static inline s64 atomic64_read(const atomic64_t *v) { - long c; + s64 c; asm volatile( " lg %0,%1\n" @@ -94,49 +94,49 @@ static inline long atomic64_read(const atomic64_t *v) return c; } -static inline void atomic64_set(atomic64_t *v, long i) +static inline void atomic64_set(atomic64_t *v, s64 i) { asm volatile( " stg %1,%0\n" : "=Q" (v->counter) : "d" (i)); } -static inline long atomic64_add_return(long i, atomic64_t *v) +static inline s64 atomic64_add_return(s64 i, atomic64_t *v) { - return __atomic64_add_barrier(i, &v->counter) + i; + return __atomic64_add_barrier(i, (long *)&v->counter) + i; } -static inline long atomic64_fetch_add(long i, atomic64_t *v) +static inline s64 atomic64_fetch_add(s64 i, atomic64_t *v) { - return __atomic64_add_barrier(i, &v->counter); + return __atomic64_add_barrier(i, (long *)&v->counter); } -static inline void atomic64_add(long i, atomic64_t *v) +static inline void atomic64_add(s64 i, atomic64_t *v) { #ifdef CONFIG_HAVE_MARCH_Z196_FEATURES if (__builtin_constant_p(i) && (i > -129) && (i < 128)) { - __atomic64_add_const(i, &v->counter); + __atomic64_add_const(i, (long *)&v->counter); return; } #endif - __atomic64_add(i, &v->counter); + __atomic64_add(i, (long *)&v->counter); } #define atomic64_xchg(v, new) (xchg(&((v)->counter), new)) -static inline long atomic64_cmpxchg(atomic64_t *v, long old, long new) +static inline s64 atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new) { - return __atomic64_cmpxchg(&v->counter, old, new); + return __atomic64_cmpxchg((long *)&v->counter, old, new); } #define ATOMIC64_OPS(op) \ -static inline void atomic64_##op(long i, atomic64_t *v) \ +static inline void atomic64_##op(s64 i, atomic64_t *v) \ { \ - __atomic64_##op(i, &v->counter); \ + __atomic64_##op(i, (long *)&v->counter); \ } \ -static inline long atomic64_fetch_##op(long i, atomic64_t *v) \ +static inline long atomic64_fetch_##op(s64 i, atomic64_t *v) \ { \ - return __atomic64_##op##_barrier(i, &v->counter); \ + return __atomic64_##op##_barrier(i, (long *)&v->counter); \ } ATOMIC64_OPS(and) @@ -145,8 +145,8 @@ ATOMIC64_OPS(xor) #undef ATOMIC64_OPS -#define atomic64_sub_return(_i, _v) atomic64_add_return(-(long)(_i), _v) -#define atomic64_fetch_sub(_i, _v) atomic64_fetch_add(-(long)(_i), _v) -#define atomic64_sub(_i, _v) atomic64_add(-(long)(_i), _v) +#define atomic64_sub_return(_i, _v) atomic64_add_return(-(s64)(_i), _v) +#define atomic64_fetch_sub(_i, _v) atomic64_fetch_add(-(s64)(_i), _v) +#define atomic64_sub(_i, _v) atomic64_add(-(s64)(_i), _v) #endif /* __ARCH_S390_ATOMIC__ */ diff --git a/arch/s390/pci/pci_debug.c b/arch/s390/pci/pci_debug.c index 6b48ca7760a7..3408c0df3ebf 100644 --- a/arch/s390/pci/pci_debug.c +++ b/arch/s390/pci/pci_debug.c @@ -74,7 +74,7 @@ static void pci_sw_counter_show(struct seq_file *m) int i; for (i = 0; i < ARRAY_SIZE(pci_sw_names); i++, counter++) - seq_printf(m, "%26s:\t%lu\n", pci_sw_names[i], + seq_printf(m, "%26s:\t%llu\n", pci_sw_names[i], atomic64_read(counter)); } diff --git a/arch/sparc/include/asm/atomic_64.h b/arch/sparc/include/asm/atomic_64.h index 6963482c81d8..b60448397d4f 100644 --- a/arch/sparc/include/asm/atomic_64.h +++ b/arch/sparc/include/asm/atomic_64.h @@ -23,15 +23,15 @@ #define ATOMIC_OP(op) \ void atomic_##op(int, atomic_t *); \ -void atomic64_##op(long, atomic64_t *); +void atomic64_##op(s64, atomic64_t *); #define ATOMIC_OP_RETURN(op) \ int atomic_##op##_return(int, atomic_t *); \ -long atomic64_##op##_return(long, atomic64_t *); +s64 atomic64_##op##_return(s64, atomic64_t *); #define ATOMIC_FETCH_OP(op) \ int atomic_fetch_##op(int, atomic_t *); \ -long atomic64_fetch_##op(long, atomic64_t *); +s64 atomic64_fetch_##op(s64, atomic64_t *); #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op) @@ -61,7 +61,7 @@ static inline int atomic_xchg(atomic_t *v, int new) ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n))) #define atomic64_xchg(v, new) (xchg(&((v)->counter), new)) -long atomic64_dec_if_positive(atomic64_t *v); +s64 atomic64_dec_if_positive(atomic64_t *v); #define atomic64_dec_if_positive atomic64_dec_if_positive #endif /* !(__ARCH_SPARC64_ATOMIC__) */ diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 3cd94a21bd53..ceb712b0a1c6 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2179,7 +2179,7 @@ static void x86_pmu_event_mapped(struct perf_event *event, struct mm_struct *mm) * For now, this can't happen because all callers hold mmap_sem * for write. If this changes, we'll need a different solution. */ - lockdep_assert_held_exclusive(&mm->mmap_sem); + lockdep_assert_held_write(&mm->mmap_sem); if (atomic_inc_return(&mm->context.perf_rdpmc_allowed) == 1) on_each_cpu_mask(mm_cpumask(mm), refresh_pce, NULL, 1); diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h index ea3d95275b43..115127c7ad28 100644 --- a/arch/x86/include/asm/atomic.h +++ b/arch/x86/include/asm/atomic.h @@ -54,7 +54,7 @@ static __always_inline void arch_atomic_add(int i, atomic_t *v) { asm volatile(LOCK_PREFIX "addl %1,%0" : "+m" (v->counter) - : "ir" (i)); + : "ir" (i) : "memory"); } /** @@ -68,7 +68,7 @@ static __always_inline void arch_atomic_sub(int i, atomic_t *v) { asm volatile(LOCK_PREFIX "subl %1,%0" : "+m" (v->counter) - : "ir" (i)); + : "ir" (i) : "memory"); } /** @@ -95,7 +95,7 @@ static __always_inline bool arch_atomic_sub_and_test(int i, atomic_t *v) static __always_inline void arch_atomic_inc(atomic_t *v) { asm volatile(LOCK_PREFIX "incl %0" - : "+m" (v->counter)); + : "+m" (v->counter) :: "memory"); } #define arch_atomic_inc arch_atomic_inc @@ -108,7 +108,7 @@ static __always_inline void arch_atomic_inc(atomic_t *v) static __always_inline void arch_atomic_dec(atomic_t *v) { asm volatile(LOCK_PREFIX "decl %0" - : "+m" (v->counter)); + : "+m" (v->counter) :: "memory"); } #define arch_atomic_dec arch_atomic_dec diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h index 6a5b0ec460da..52cfaecb13f9 100644 --- a/arch/x86/include/asm/atomic64_32.h +++ b/arch/x86/include/asm/atomic64_32.h @@ -9,7 +9,7 @@ /* An 64bit atomic type */ typedef struct { - u64 __aligned(8) counter; + s64 __aligned(8) counter; } atomic64_t; #define ATOMIC64_INIT(val) { (val) } @@ -71,8 +71,7 @@ ATOMIC64_DECL(add_unless); * the old value. */ -static inline long long arch_atomic64_cmpxchg(atomic64_t *v, long long o, - long long n) +static inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n) { return arch_cmpxchg64(&v->counter, o, n); } @@ -85,9 +84,9 @@ static inline long long arch_atomic64_cmpxchg(atomic64_t *v, long long o, * Atomically xchgs the value of @v to @n and returns * the old value. */ -static inline long long arch_atomic64_xchg(atomic64_t *v, long long n) +static inline s64 arch_atomic64_xchg(atomic64_t *v, s64 n) { - long long o; + s64 o; unsigned high = (unsigned)(n >> 32); unsigned low = (unsigned)n; alternative_atomic64(xchg, "=&A" (o), @@ -103,7 +102,7 @@ static inline long long arch_atomic64_xchg(atomic64_t *v, long long n) * * Atomically sets the value of @v to @n. */ -static inline void arch_atomic64_set(atomic64_t *v, long long i) +static inline void arch_atomic64_set(atomic64_t *v, s64 i) { unsigned high = (unsigned)(i >> 32); unsigned low = (unsigned)i; @@ -118,9 +117,9 @@ static inline void arch_atomic64_set(atomic64_t *v, long long i) * * Atomically reads the value of @v and returns it. */ -static inline long long arch_atomic64_read(const atomic64_t *v) +static inline s64 arch_atomic64_read(const atomic64_t *v) { - long long r; + s64 r; alternative_atomic64(read, "=&A" (r), "c" (v) : "memory"); return r; } @@ -132,7 +131,7 @@ static inline long long arch_atomic64_read(const atomic64_t *v) * * Atomically adds @i to @v and returns @i + *@v */ -static inline long long arch_atomic64_add_return(long long i, atomic64_t *v) +static inline s64 arch_atomic64_add_return(s64 i, atomic64_t *v) { alternative_atomic64(add_return, ASM_OUTPUT2("+A" (i), "+c" (v)), @@ -143,7 +142,7 @@ static inline long long arch_atomic64_add_return(long long i, atomic64_t *v) /* * Other variants with different arithmetic operators: */ -static inline long long arch_atomic64_sub_return(long long i, atomic64_t *v) +static inline s64 arch_atomic64_sub_return(s64 i, atomic64_t *v) { alternative_atomic64(sub_return, ASM_OUTPUT2("+A" (i), "+c" (v)), @@ -151,18 +150,18 @@ static inline long long arch_atomic64_sub_return(long long i, atomic64_t *v) return i; } -static inline long long arch_atomic64_inc_return(atomic64_t *v) +static inline s64 arch_atomic64_inc_return(atomic64_t *v) { - long long a; + s64 a; alternative_atomic64(inc_return, "=&A" (a), "S" (v) : "memory", "ecx"); return a; } #define arch_atomic64_inc_return arch_atomic64_inc_return -static inline long long arch_atomic64_dec_return(atomic64_t *v) +static inline s64 arch_atomic64_dec_return(atomic64_t *v) { - long long a; + s64 a; alternative_atomic64(dec_return, "=&A" (a), "S" (v) : "memory", "ecx"); return a; @@ -176,7 +175,7 @@ static inline long long arch_atomic64_dec_return(atomic64_t *v) * * Atomically adds @i to @v. */ -static inline long long arch_atomic64_add(long long i, atomic64_t *v) +static inline s64 arch_atomic64_add(s64 i, atomic64_t *v) { __alternative_atomic64(add, add_return, ASM_OUTPUT2("+A" (i), "+c" (v)), @@ -191,7 +190,7 @@ static inline long long arch_atomic64_add(long long i, atomic64_t *v) * * Atomically subtracts @i from @v. */ -static inline long long arch_atomic64_sub(long long i, atomic64_t *v) +static inline s64 arch_atomic64_sub(s64 i, atomic64_t *v) { __alternative_atomic64(sub, sub_return, ASM_OUTPUT2("+A" (i), "+c" (v)), @@ -234,8 +233,7 @@ static inline void arch_atomic64_dec(atomic64_t *v) * Atomically adds @a to @v, so long as it was not @u. * Returns non-zero if the add was done, zero otherwise. */ -static inline int arch_atomic64_add_unless(atomic64_t *v, long long a, - long long u) +static inline int arch_atomic64_add_unless(atomic64_t *v, s64 a, s64 u) { unsigned low = (unsigned)u; unsigned high = (unsigned)(u >> 32); @@ -254,9 +252,9 @@ static inline int arch_atomic64_inc_not_zero(atomic64_t *v) } #define arch_atomic64_inc_not_zero arch_atomic64_inc_not_zero -static inline long long arch_atomic64_dec_if_positive(atomic64_t *v) +static inline s64 arch_atomic64_dec_if_positive(atomic64_t *v) { - long long r; + s64 r; alternative_atomic64(dec_if_positive, "=&A" (r), "S" (v) : "ecx", "memory"); return r; @@ -266,17 +264,17 @@ static inline long long arch_atomic64_dec_if_positive(atomic64_t *v) #undef alternative_atomic64 #undef __alternative_atomic64 -static inline void arch_atomic64_and(long long i, atomic64_t *v) +static inline void arch_atomic64_and(s64 i, atomic64_t *v) { - long long old, c = 0; + s64 old, c = 0; while ((old = arch_atomic64_cmpxchg(v, c, c & i)) != c) c = old; } -static inline long long arch_atomic64_fetch_and(long long i, atomic64_t *v) +static inline s64 arch_atomic64_fetch_and(s64 i, atomic64_t *v) { - long long old, c = 0; + s64 old, c = 0; while ((old = arch_atomic64_cmpxchg(v, c, c & i)) != c) c = old; @@ -284,17 +282,17 @@ static inline long long arch_atomic64_fetch_and(long long i, atomic64_t *v) return old; } -static inline void arch_atomic64_or(long long i, atomic64_t *v) +static inline void arch_atomic64_or(s64 i, atomic64_t *v) { - long long old, c = 0; + s64 old, c = 0; while ((old = arch_atomic64_cmpxchg(v, c, c | i)) != c) c = old; } -static inline long long arch_atomic64_fetch_or(long long i, atomic64_t *v) +static inline s64 arch_atomic64_fetch_or(s64 i, atomic64_t *v) { - long long old, c = 0; + s64 old, c = 0; while ((old = arch_atomic64_cmpxchg(v, c, c | i)) != c) c = old; @@ -302,17 +300,17 @@ static inline long long arch_atomic64_fetch_or(long long i, atomic64_t *v) return old; } -static inline void arch_atomic64_xor(long long i, atomic64_t *v) +static inline void arch_atomic64_xor(s64 i, atomic64_t *v) { - long long old, c = 0; + s64 old, c = 0; while ((old = arch_atomic64_cmpxchg(v, c, c ^ i)) != c) c = old; } -static inline long long arch_atomic64_fetch_xor(long long i, atomic64_t *v) +static inline s64 arch_atomic64_fetch_xor(s64 i, atomic64_t *v) { - long long old, c = 0; + s64 old, c = 0; while ((old = arch_atomic64_cmpxchg(v, c, c ^ i)) != c) c = old; @@ -320,9 +318,9 @@ static inline long long arch_atomic64_fetch_xor(long long i, atomic64_t *v) return old; } -static inline long long arch_atomic64_fetch_add(long long i, atomic64_t *v) +static inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v) { - long long old, c = 0; + s64 old, c = 0; while ((old = arch_atomic64_cmpxchg(v, c, c + i)) != c) c = old; diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h index dadc20adba21..95c6ceac66b9 100644 --- a/arch/x86/include/asm/atomic64_64.h +++ b/arch/x86/include/asm/atomic64_64.h @@ -17,7 +17,7 @@ * Atomically reads the value of @v. * Doesn't imply a read memory barrier. */ -static inline long arch_atomic64_read(const atomic64_t *v) +static inline s64 arch_atomic64_read(const atomic64_t *v) { return READ_ONCE((v)->counter); } @@ -29,7 +29,7 @@ static inline long arch_atomic64_read(const atomic64_t *v) * * Atomically sets the value of @v to @i. */ -static inline void arch_atomic64_set(atomic64_t *v, long i) +static inline void arch_atomic64_set(atomic64_t *v, s64 i) { WRITE_ONCE(v->counter, i); } @@ -41,11 +41,11 @@ static inline void arch_atomic64_set(atomic64_t *v, long i) * * Atomically adds @i to @v. */ -static __always_inline void arch_atomic64_add(long i, atomic64_t *v) +static __always_inline void arch_atomic64_add(s64 i, atomic64_t *v) { asm volatile(LOCK_PREFIX "addq %1,%0" : "=m" (v->counter) - : "er" (i), "m" (v->counter)); + : "er" (i), "m" (v->counter) : "memory"); } /** @@ -55,11 +55,11 @@ static __always_inline void arch_atomic64_add(long i, atomic64_t *v) * * Atomically subtracts @i from @v. */ -static inline void arch_atomic64_sub(long i, atomic64_t *v) +static inline void arch_atomic64_sub(s64 i, atomic64_t *v) { asm volatile(LOCK_PREFIX "subq %1,%0" : "=m" (v->counter) - : "er" (i), "m" (v->counter)); + : "er" (i), "m" (v->counter) : "memory"); } /** @@ -71,7 +71,7 @@ static inline void arch_atomic64_sub(long i, atomic64_t *v) * true if the result is zero, or false for all * other cases. */ -static inline bool arch_atomic64_sub_and_test(long i, atomic64_t *v) +static inline bool arch_atomic64_sub_and_test(s64 i, atomic64_t *v) { return GEN_BINARY_RMWcc(LOCK_PREFIX "subq", v->counter, e, "er", i); } @@ -87,7 +87,7 @@ static __always_inline void arch_atomic64_inc(atomic64_t *v) { asm volatile(LOCK_PREFIX "incq %0" : "=m" (v->counter) - : "m" (v->counter)); + : "m" (v->counter) : "memory"); } #define arch_atomic64_inc arch_atomic64_inc @@ -101,7 +101,7 @@ static __always_inline void arch_atomic64_dec(atomic64_t *v) { asm volatile(LOCK_PREFIX "decq %0" : "=m" (v->counter) - : "m" (v->counter)); + : "m" (v->counter) : "memory"); } #define arch_atomic64_dec arch_atomic64_dec @@ -142,7 +142,7 @@ static inline bool arch_atomic64_inc_and_test(atomic64_t *v) * if the result is negative, or false when * result is greater than or equal to zero. */ -static inline bool arch_atomic64_add_negative(long i, atomic64_t *v) +static inline bool arch_atomic64_add_negative(s64 i, atomic64_t *v) { return GEN_BINARY_RMWcc(LOCK_PREFIX "addq", v->counter, s, "er", i); } @@ -155,43 +155,43 @@ static inline bool arch_atomic64_add_negative(long i, atomic64_t *v) * * Atomically adds @i to @v and returns @i + @v */ -static __always_inline long arch_atomic64_add_return(long i, atomic64_t *v) +static __always_inline s64 arch_atomic64_add_return(s64 i, atomic64_t *v) { return i + xadd(&v->counter, i); } -static inline long arch_atomic64_sub_return(long i, atomic64_t *v) +static inline s64 arch_atomic64_sub_return(s64 i, atomic64_t *v) { return arch_atomic64_add_return(-i, v); } -static inline long arch_atomic64_fetch_add(long i, atomic64_t *v) +static inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v) { return xadd(&v->counter, i); } -static inline long arch_atomic64_fetch_sub(long i, atomic64_t *v) +static inline s64 arch_atomic64_fetch_sub(s64 i, atomic64_t *v) { return xadd(&v->counter, -i); } -static inline long arch_atomic64_cmpxchg(atomic64_t *v, long old, long new) +static inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new) { return arch_cmpxchg(&v->counter, old, new); } #define arch_atomic64_try_cmpxchg arch_atomic64_try_cmpxchg -static __always_inline bool arch_atomic64_try_cmpxchg(atomic64_t *v, s64 *old, long new) +static __always_inline bool arch_atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 new) { return try_cmpxchg(&v->counter, old, new); } -static inline long arch_atomic64_xchg(atomic64_t *v, long new) +static inline s64 arch_atomic64_xchg(atomic64_t *v, s64 new) { return arch_xchg(&v->counter, new); } -static inline void arch_atomic64_and(long i, atomic64_t *v) +static inline void arch_atomic64_and(s64 i, atomic64_t *v) { asm volatile(LOCK_PREFIX "andq %1,%0" : "+m" (v->counter) @@ -199,7 +199,7 @@ static inline void arch_atomic64_and(long i, atomic64_t *v) : "memory"); } -static inline long arch_atomic64_fetch_and(long i, atomic64_t *v) +static inline s64 arch_atomic64_fetch_and(s64 i, atomic64_t *v) { s64 val = arch_atomic64_read(v); @@ -208,7 +208,7 @@ static inline long arch_atomic64_fetch_and(long i, atomic64_t *v) return val; } -static inline void arch_atomic64_or(long i, atomic64_t *v) +static inline void arch_atomic64_or(s64 i, atomic64_t *v) { asm volatile(LOCK_PREFIX "orq %1,%0" : "+m" (v->counter) @@ -216,7 +216,7 @@ static inline void arch_atomic64_or(long i, atomic64_t *v) : "memory"); } -static inline long arch_atomic64_fetch_or(long i, atomic64_t *v) +static inline s64 arch_atomic64_fetch_or(s64 i, atomic64_t *v) { s64 val = arch_atomic64_read(v); @@ -225,7 +225,7 @@ static inline long arch_atomic64_fetch_or(long i, atomic64_t *v) return val; } -static inline void arch_atomic64_xor(long i, atomic64_t *v) +static inline void arch_atomic64_xor(s64 i, atomic64_t *v) { asm volatile(LOCK_PREFIX "xorq %1,%0" : "+m" (v->counter) @@ -233,7 +233,7 @@ static inline void arch_atomic64_xor(long i, atomic64_t *v) : "memory"); } -static inline long arch_atomic64_fetch_xor(long i, atomic64_t *v) +static inline s64 arch_atomic64_fetch_xor(s64 i, atomic64_t *v) { s64 val = arch_atomic64_read(v); diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h index 14de0432d288..84f848c2541a 100644 --- a/arch/x86/include/asm/barrier.h +++ b/arch/x86/include/asm/barrier.h @@ -80,8 +80,8 @@ do { \ }) /* Atomic operations are already serializing on x86 */ -#define __smp_mb__before_atomic() barrier() -#define __smp_mb__after_atomic() barrier() +#define __smp_mb__before_atomic() do { } while (0) +#define __smp_mb__after_atomic() do { } while (0) #include <asm-generic/barrier.h> diff --git a/arch/x86/include/asm/irq_regs.h b/arch/x86/include/asm/irq_regs.h index 8f3bee821e6c..187ce59aea28 100644 --- a/arch/x86/include/asm/irq_regs.h +++ b/arch/x86/include/asm/irq_regs.h @@ -16,7 +16,7 @@ DECLARE_PER_CPU(struct pt_regs *, irq_regs); static inline struct pt_regs *get_irq_regs(void) { - return this_cpu_read(irq_regs); + return __this_cpu_read(irq_regs); } static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs) @@ -24,7 +24,7 @@ static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs) struct pt_regs *old_regs; old_regs = get_irq_regs(); - this_cpu_write(irq_regs, new_regs); + __this_cpu_write(irq_regs, new_regs); return old_regs; } diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h index 65191ce8e1cf..06c3cc22a058 100644 --- a/arch/x86/include/asm/jump_label.h +++ b/arch/x86/include/asm/jump_label.h @@ -2,6 +2,8 @@ #ifndef _ASM_X86_JUMP_LABEL_H #define _ASM_X86_JUMP_LABEL_H +#define HAVE_JUMP_LABEL_BATCH + #define JUMP_LABEL_NOP_SIZE 5 #ifdef CONFIG_X86_64 diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h index 1a19d11cfbbd..2278797c769d 100644 --- a/arch/x86/include/asm/percpu.h +++ b/arch/x86/include/asm/percpu.h @@ -87,7 +87,7 @@ * don't give an lvalue though). */ extern void __bad_percpu_size(void); -#define percpu_to_op(op, var, val) \ +#define percpu_to_op(qual, op, var, val) \ do { \ typedef typeof(var) pto_T__; \ if (0) { \ @@ -97,22 +97,22 @@ do { \ } \ switch (sizeof(var)) { \ case 1: \ - asm(op "b %1,"__percpu_arg(0) \ + asm qual (op "b %1,"__percpu_arg(0) \ : "+m" (var) \ : "qi" ((pto_T__)(val))); \ break; \ case 2: \ - asm(op "w %1,"__percpu_arg(0) \ + asm qual (op "w %1,"__percpu_arg(0) \ : "+m" (var) \ : "ri" ((pto_T__)(val))); \ break; \ case 4: \ - asm(op "l %1,"__percpu_arg(0) \ + asm qual (op "l %1,"__percpu_arg(0) \ : "+m" (var) \ : "ri" ((pto_T__)(val))); \ break; \ case 8: \ - asm(op "q %1,"__percpu_arg(0) \ + asm qual (op "q %1,"__percpu_arg(0) \ : "+m" (var) \ : "re" ((pto_T__)(val))); \ break; \ @@ -124,7 +124,7 @@ do { \ * Generate a percpu add to memory instruction and optimize code * if one is added or subtracted. */ -#define percpu_add_op(var, val) \ +#define percpu_add_op(qual, var, val) \ do { \ typedef typeof(var) pao_T__; \ const int pao_ID__ = (__builtin_constant_p(val) && \ @@ -138,41 +138,41 @@ do { \ switch (sizeof(var)) { \ case 1: \ if (pao_ID__ == 1) \ - asm("incb "__percpu_arg(0) : "+m" (var)); \ + asm qual ("incb "__percpu_arg(0) : "+m" (var)); \ else if (pao_ID__ == -1) \ - asm("decb "__percpu_arg(0) : "+m" (var)); \ + asm qual ("decb "__percpu_arg(0) : "+m" (var)); \ else \ - asm("addb %1, "__percpu_arg(0) \ + asm qual ("addb %1, "__percpu_arg(0) \ : "+m" (var) \ : "qi" ((pao_T__)(val))); \ break; \ case 2: \ if (pao_ID__ == 1) \ - asm("incw "__percpu_arg(0) : "+m" (var)); \ + asm qual ("incw "__percpu_arg(0) : "+m" (var)); \ else if (pao_ID__ == -1) \ - asm("decw "__percpu_arg(0) : "+m" (var)); \ + asm qual ("decw "__percpu_arg(0) : "+m" (var)); \ else \ - asm("addw %1, "__percpu_arg(0) \ + asm qual ("addw %1, "__percpu_arg(0) \ : "+m" (var) \ : "ri" ((pao_T__)(val))); \ break; \ case 4: \ if (pao_ID__ == 1) \ - asm("incl "__percpu_arg(0) : "+m" (var)); \ + asm qual ("incl "__percpu_arg(0) : "+m" (var)); \ else if (pao_ID__ == -1) \ - asm("decl "__percpu_arg(0) : "+m" (var)); \ + asm qual ("decl "__percpu_arg(0) : "+m" (var)); \ else \ - asm("addl %1, "__percpu_arg(0) \ + asm qual ("addl %1, "__percpu_arg(0) \ : "+m" (var) \ : "ri" ((pao_T__)(val))); \ break; \ case 8: \ if (pao_ID__ == 1) \ - asm("incq "__percpu_arg(0) : "+m" (var)); \ + asm qual ("incq "__percpu_arg(0) : "+m" (var)); \ else if (pao_ID__ == -1) \ - asm("decq "__percpu_arg(0) : "+m" (var)); \ + asm qual ("decq "__percpu_arg(0) : "+m" (var)); \ else \ - asm("addq %1, "__percpu_arg(0) \ + asm qual ("addq %1, "__percpu_arg(0) \ : "+m" (var) \ : "re" ((pao_T__)(val))); \ break; \ @@ -180,27 +180,27 @@ do { \ } \ } while (0) -#define percpu_from_op(op, var) \ +#define percpu_from_op(qual, op, var) \ ({ \ typeof(var) pfo_ret__; \ switch (sizeof(var)) { \ case 1: \ - asm volatile(op "b "__percpu_arg(1)",%0"\ + asm qual (op "b "__percpu_arg(1)",%0" \ : "=q" (pfo_ret__) \ : "m" (var)); \ break; \ case 2: \ - asm volatile(op "w "__percpu_arg(1)",%0"\ + asm qual (op "w "__percpu_arg(1)",%0" \ : "=r" (pfo_ret__) \ : "m" (var)); \ break; \ case 4: \ - asm volatile(op "l "__percpu_arg(1)",%0"\ + asm qual (op "l "__percpu_arg(1)",%0" \ : "=r" (pfo_ret__) \ : "m" (var)); \ break; \ case 8: \ - asm volatile(op "q "__percpu_arg(1)",%0"\ + asm qual (op "q "__percpu_arg(1)",%0" \ : "=r" (pfo_ret__) \ : "m" (var)); \ break; \ @@ -238,23 +238,23 @@ do { \ pfo_ret__; \ }) -#define percpu_unary_op(op, var) \ +#define percpu_unary_op(qual, op, var) \ ({ \ switch (sizeof(var)) { \ case 1: \ - asm(op "b "__percpu_arg(0) \ + asm qual (op "b "__percpu_arg(0) \ : "+m" (var)); \ break; \ case 2: \ - asm(op "w "__percpu_arg(0) \ + asm qual (op "w "__percpu_arg(0) \ : "+m" (var)); \ break; \ case 4: \ - asm(op "l "__percpu_arg(0) \ + asm qual (op "l "__percpu_arg(0) \ : "+m" (var)); \ break; \ case 8: \ - asm(op "q "__percpu_arg(0) \ + asm qual (op "q "__percpu_arg(0) \ : "+m" (var)); \ break; \ default: __bad_percpu_size(); \ @@ -264,27 +264,27 @@ do { \ /* * Add return operation */ -#define percpu_add_return_op(var, val) \ +#define percpu_add_return_op(qual, var, val) \ ({ \ typeof(var) paro_ret__ = val; \ switch (sizeof(var)) { \ case 1: \ - asm("xaddb %0, "__percpu_arg(1) \ + asm qual ("xaddb %0, "__percpu_arg(1) \ : "+q" (paro_ret__), "+m" (var) \ : : "memory"); \ break; \ case 2: \ - asm("xaddw %0, "__percpu_arg(1) \ + asm qual ("xaddw %0, "__percpu_arg(1) \ : "+r" (paro_ret__), "+m" (var) \ : : "memory"); \ break; \ case 4: \ - asm("xaddl %0, "__percpu_arg(1) \ + asm qual ("xaddl %0, "__percpu_arg(1) \ : "+r" (paro_ret__), "+m" (var) \ : : "memory"); \ break; \ case 8: \ - asm("xaddq %0, "__percpu_arg(1) \ + asm qual ("xaddq %0, "__percpu_arg(1) \ : "+re" (paro_ret__), "+m" (var) \ : : "memory"); \ break; \ @@ -299,13 +299,13 @@ do { \ * expensive due to the implied lock prefix. The processor cannot prefetch * cachelines if xchg is used. */ -#define percpu_xchg_op(var, nval) \ +#define percpu_xchg_op(qual, var, nval) \ ({ \ typeof(var) pxo_ret__; \ typeof(var) pxo_new__ = (nval); \ switch (sizeof(var)) { \ case 1: \ - asm("\n\tmov "__percpu_arg(1)",%%al" \ + asm qual ("\n\tmov "__percpu_arg(1)",%%al" \ "\n1:\tcmpxchgb %2, "__percpu_arg(1) \ "\n\tjnz 1b" \ : "=&a" (pxo_ret__), "+m" (var) \ @@ -313,7 +313,7 @@ do { \ : "memory"); \ break; \ case 2: \ - asm("\n\tmov "__percpu_arg(1)",%%ax" \ + asm qual ("\n\tmov "__percpu_arg(1)",%%ax" \ "\n1:\tcmpxchgw %2, "__percpu_arg(1) \ "\n\tjnz 1b" \ : "=&a" (pxo_ret__), "+m" (var) \ @@ -321,7 +321,7 @@ do { \ : "memory"); \ break; \ case 4: \ - asm("\n\tmov "__percpu_arg(1)",%%eax" \ + asm qual ("\n\tmov "__percpu_arg(1)",%%eax" \ "\n1:\tcmpxchgl %2, "__percpu_arg(1) \ "\n\tjnz 1b" \ : "=&a" (pxo_ret__), "+m" (var) \ @@ -329,7 +329,7 @@ do { \ : "memory"); \ break; \ case 8: \ - asm("\n\tmov "__percpu_arg(1)",%%rax" \ + asm qual ("\n\tmov "__percpu_arg(1)",%%rax" \ "\n1:\tcmpxchgq %2, "__percpu_arg(1) \ "\n\tjnz 1b" \ : "=&a" (pxo_ret__), "+m" (var) \ @@ -345,32 +345,32 @@ do { \ * cmpxchg has no such implied lock semantics as a result it is much * more efficient for cpu local operations. */ -#define percpu_cmpxchg_op(var, oval, nval) \ +#define percpu_cmpxchg_op(qual, var, oval, nval) \ ({ \ typeof(var) pco_ret__; \ typeof(var) pco_old__ = (oval); \ typeof(var) pco_new__ = (nval); \ switch (sizeof(var)) { \ case 1: \ - asm("cmpxchgb %2, "__percpu_arg(1) \ + asm qual ("cmpxchgb %2, "__percpu_arg(1) \ : "=a" (pco_ret__), "+m" (var) \ : "q" (pco_new__), "0" (pco_old__) \ : "memory"); \ break; \ case 2: \ - asm("cmpxchgw %2, "__percpu_arg(1) \ + asm qual ("cmpxchgw %2, "__percpu_arg(1) \ : "=a" (pco_ret__), "+m" (var) \ : "r" (pco_new__), "0" (pco_old__) \ : "memory"); \ break; \ case 4: \ - asm("cmpxchgl %2, "__percpu_arg(1) \ + asm qual ("cmpxchgl %2, "__percpu_arg(1) \ : "=a" (pco_ret__), "+m" (var) \ : "r" (pco_new__), "0" (pco_old__) \ : "memory"); \ break; \ case 8: \ - asm("cmpxchgq %2, "__percpu_arg(1) \ + asm qual ("cmpxchgq %2, "__percpu_arg(1) \ : "=a" (pco_ret__), "+m" (var) \ : "r" (pco_new__), "0" (pco_old__) \ : "memory"); \ @@ -391,58 +391,70 @@ do { \ */ #define this_cpu_read_stable(var) percpu_stable_op("mov", var) -#define raw_cpu_read_1(pcp) percpu_from_op("mov", pcp) -#define raw_cpu_read_2(pcp) percpu_from_op("mov", pcp) -#define raw_cpu_read_4(pcp) percpu_from_op("mov", pcp) - -#define raw_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val) -#define raw_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val) -#define raw_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val) -#define raw_cpu_add_1(pcp, val) percpu_add_op((pcp), val) -#define raw_cpu_add_2(pcp, val) percpu_add_op((pcp), val) -#define raw_cpu_add_4(pcp, val) percpu_add_op((pcp), val) -#define raw_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val) -#define raw_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val) -#define raw_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val) -#define raw_cpu_or_1(pcp, val) percpu_to_op("or", (pcp), val) -#define raw_cpu_or_2(pcp, val) percpu_to_op("or", (pcp), val) -#define raw_cpu_or_4(pcp, val) percpu_to_op("or", (pcp), val) -#define raw_cpu_xchg_1(pcp, val) percpu_xchg_op(pcp, val) -#define raw_cpu_xchg_2(pcp, val) percpu_xchg_op(pcp, val) -#define raw_cpu_xchg_4(pcp, val) percpu_xchg_op(pcp, val) - -#define this_cpu_read_1(pcp) percpu_from_op("mov", pcp) -#define this_cpu_read_2(pcp) percpu_from_op("mov", pcp) -#define this_cpu_read_4(pcp) percpu_from_op("mov", pcp) -#define this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val) -#define this_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val) -#define this_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val) -#define this_cpu_add_1(pcp, val) percpu_add_op((pcp), val) -#define this_cpu_add_2(pcp, val) percpu_add_op((pcp), val) -#define this_cpu_add_4(pcp, val) percpu_add_op((pcp), val) -#define this_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val) -#define this_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val) -#define this_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val) -#define this_cpu_or_1(pcp, val) percpu_to_op("or", (pcp), val) -#define this_cpu_or_2(pcp, val) percpu_to_op("or", (pcp), val) -#define this_cpu_or_4(pcp, val) percpu_to_op("or", (pcp), val) -#define this_cpu_xchg_1(pcp, nval) percpu_xchg_op(pcp, nval) -#define this_cpu_xchg_2(pcp, nval) percpu_xchg_op(pcp, nval) -#define this_cpu_xchg_4(pcp, nval) percpu_xchg_op(pcp, nval) - -#define raw_cpu_add_return_1(pcp, val) percpu_add_return_op(pcp, val) -#define raw_cpu_add_return_2(pcp, val) percpu_add_return_op(pcp, val) -#define raw_cpu_add_return_4(pcp, val) percpu_add_return_op(pcp, val) -#define raw_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval) -#define raw_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval) -#define raw_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval) - -#define this_cpu_add_return_1(pcp, val) percpu_add_return_op(pcp, val) -#define this_cpu_add_return_2(pcp, val) percpu_add_return_op(pcp, val) -#define this_cpu_add_return_4(pcp, val) percpu_add_return_op(pcp, val) -#define this_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval) -#define this_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval) -#define this_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval) +#define raw_cpu_read_1(pcp) percpu_from_op(, "mov", pcp) +#define raw_cpu_read_2(pcp) percpu_from_op(, "mov", pcp) +#define raw_cpu_read_4(pcp) percpu_from_op(, "mov", pcp) + +#define raw_cpu_write_1(pcp, val) percpu_to_op(, "mov", (pcp), val) +#define raw_cpu_write_2(pcp, val) percpu_to_op(, "mov", (pcp), val) +#define raw_cpu_write_4(pcp, val) percpu_to_op(, "mov", (pcp), val) +#define raw_cpu_add_1(pcp, val) percpu_add_op(, (pcp), val) +#define raw_cpu_add_2(pcp, val) percpu_add_op(, (pcp), val) +#define raw_cpu_add_4(pcp, val) percpu_add_op(, (pcp), val) +#define raw_cpu_and_1(pcp, val) percpu_to_op(, "and", (pcp), val) +#define raw_cpu_and_2(pcp, val) percpu_to_op(, "and", (pcp), val) +#define raw_cpu_and_4(pcp, val) percpu_to_op(, "and", (pcp), val) +#define raw_cpu_or_1(pcp, val) percpu_to_op(, "or", (pcp), val) +#define raw_cpu_or_2(pcp, val) percpu_to_op(, "or", (pcp), val) +#define raw_cpu_or_4(pcp, val) percpu_to_op(, "or", (pcp), val) + +/* + * raw_cpu_xchg() can use a load-store since it is not required to be + * IRQ-safe. + */ +#define raw_percpu_xchg_op(var, nval) \ +({ \ + typeof(var) pxo_ret__ = raw_cpu_read(var); \ + raw_cpu_write(var, (nval)); \ + pxo_ret__; \ +}) + +#define raw_cpu_xchg_1(pcp, val) raw_percpu_xchg_op(pcp, val) +#define raw_cpu_xchg_2(pcp, val) raw_percpu_xchg_op(pcp, val) +#define raw_cpu_xchg_4(pcp, val) raw_percpu_xchg_op(pcp, val) + +#define this_cpu_read_1(pcp) percpu_from_op(volatile, "mov", pcp) +#define this_cpu_read_2(pcp) percpu_from_op(volatile, "mov", pcp) +#define this_cpu_read_4(pcp) percpu_from_op(volatile, "mov", pcp) +#define this_cpu_write_1(pcp, val) percpu_to_op(volatile, "mov", (pcp), val) +#define this_cpu_write_2(pcp, val) percpu_to_op(volatile, "mov", (pcp), val) +#define this_cpu_write_4(pcp, val) percpu_to_op(volatile, "mov", (pcp), val) +#define this_cpu_add_1(pcp, val) percpu_add_op(volatile, (pcp), val) +#define this_cpu_add_2(pcp, val) percpu_add_op(volatile, (pcp), val) +#define this_cpu_add_4(pcp, val) percpu_add_op(volatile, (pcp), val) +#define this_cpu_and_1(pcp, val) percpu_to_op(volatile, "and", (pcp), val) +#define this_cpu_and_2(pcp, val) percpu_to_op(volatile, "and", (pcp), val) +#define this_cpu_and_4(pcp, val) percpu_to_op(volatile, "and", (pcp), val) +#define this_cpu_or_1(pcp, val) percpu_to_op(volatile, "or", (pcp), val) +#define this_cpu_or_2(pcp, val) percpu_to_op(volatile, "or", (pcp), val) +#define this_cpu_or_4(pcp, val) percpu_to_op(volatile, "or", (pcp), val) +#define this_cpu_xchg_1(pcp, nval) percpu_xchg_op(volatile, pcp, nval) +#define this_cpu_xchg_2(pcp, nval) percpu_xchg_op(volatile, pcp, nval) +#define this_cpu_xchg_4(pcp, nval) percpu_xchg_op(volatile, pcp, nval) + +#define raw_cpu_add_return_1(pcp, val) percpu_add_return_op(, pcp, val) +#define raw_cpu_add_return_2(pcp, val) percpu_add_return_op(, pcp, val) +#define raw_cpu_add_return_4(pcp, val) percpu_add_return_op(, pcp, val) +#define raw_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(, pcp, oval, nval) +#define raw_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(, pcp, oval, nval) +#define raw_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(, pcp, oval, nval) + +#define this_cpu_add_return_1(pcp, val) percpu_add_return_op(volatile, pcp, val) +#define this_cpu_add_return_2(pcp, val) percpu_add_return_op(volatile, pcp, val) +#define this_cpu_add_return_4(pcp, val) percpu_add_return_op(volatile, pcp, val) +#define this_cpu_cmpxchg_1(pcp, oval, nval) percpu_cmpxchg_op(volatile, pcp, oval, nval) +#define this_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(volatile, pcp, oval, nval) +#define this_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(volatile, pcp, oval, nval) #ifdef CONFIG_X86_CMPXCHG64 #define percpu_cmpxchg8b_double(pcp1, pcp2, o1, o2, n1, n2) \ @@ -466,23 +478,23 @@ do { \ * 32 bit must fall back to generic operations. */ #ifdef CONFIG_X86_64 -#define raw_cpu_read_8(pcp) percpu_from_op("mov", pcp) -#define raw_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val) -#define raw_cpu_add_8(pcp, val) percpu_add_op((pcp), val) -#define raw_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val) -#define raw_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val) -#define raw_cpu_add_return_8(pcp, val) percpu_add_return_op(pcp, val) -#define raw_cpu_xchg_8(pcp, nval) percpu_xchg_op(pcp, nval) -#define raw_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval) - -#define this_cpu_read_8(pcp) percpu_from_op("mov", pcp) -#define this_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val) -#define this_cpu_add_8(pcp, val) percpu_add_op((pcp), val) -#define this_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val) -#define this_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val) -#define this_cpu_add_return_8(pcp, val) percpu_add_return_op(pcp, val) -#define this_cpu_xchg_8(pcp, nval) percpu_xchg_op(pcp, nval) -#define this_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval) +#define raw_cpu_read_8(pcp) percpu_from_op(, "mov", pcp) +#define raw_cpu_write_8(pcp, val) percpu_to_op(, "mov", (pcp), val) +#define raw_cpu_add_8(pcp, val) percpu_add_op(, (pcp), val) +#define raw_cpu_and_8(pcp, val) percpu_to_op(, "and", (pcp), val) +#define raw_cpu_or_8(pcp, val) percpu_to_op(, "or", (pcp), val) +#define raw_cpu_add_return_8(pcp, val) percpu_add_return_op(, pcp, val) +#define raw_cpu_xchg_8(pcp, nval) raw_percpu_xchg_op(pcp, nval) +#define raw_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(, pcp, oval, nval) + +#define this_cpu_read_8(pcp) percpu_from_op(volatile, "mov", pcp) +#define this_cpu_write_8(pcp, val) percpu_to_op(volatile, "mov", (pcp), val) +#define this_cpu_add_8(pcp, val) percpu_add_op(volatile, (pcp), val) +#define this_cpu_and_8(pcp, val) percpu_to_op(volatile, "and", (pcp), val) +#define this_cpu_or_8(pcp, val) percpu_to_op(volatile, "or", (pcp), val) +#define this_cpu_add_return_8(pcp, val) percpu_add_return_op(volatile, pcp, val) +#define this_cpu_xchg_8(pcp, nval) percpu_xchg_op(volatile, pcp, nval) +#define this_cpu_cmpxchg_8(pcp, oval, nval) percpu_cmpxchg_op(volatile, pcp, oval, nval) /* * Pretty complex macro to generate cmpxchg16 instruction. The instruction diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h index da545df207b2..0d3fe060a44f 100644 --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -162,7 +162,8 @@ __visible void smp_call_function_single_interrupt(struct pt_regs *r); * from the initial startup. We map APIC_BASE very early in page_setup(), * so this is correct in the x86 case. */ -#define raw_smp_processor_id() (this_cpu_read(cpu_number)) +#define raw_smp_processor_id() this_cpu_read(cpu_number) +#define __smp_processor_id() __this_cpu_read(cpu_number) #ifdef CONFIG_X86_32 extern int safe_smp_processor_id(void); diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index 880b5515b1d6..d83e9f771d86 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -18,6 +18,20 @@ static inline void apply_paravirt(struct paravirt_patch_site *start, #define __parainstructions_end NULL #endif +/* + * Currently, the max observed size in the kernel code is + * JUMP_LABEL_NOP_SIZE/RELATIVEJUMP_SIZE, which are 5. + * Raise it if needed. + */ +#define POKE_MAX_OPCODE_SIZE 5 + +struct text_poke_loc { + void *detour; + void *addr; + size_t len; + const char opcode[POKE_MAX_OPCODE_SIZE]; +}; + extern void text_poke_early(void *addr, const void *opcode, size_t len); /* @@ -38,6 +52,7 @@ extern void *text_poke(void *addr, const void *opcode, size_t len); extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len); extern int poke_int3_handler(struct pt_regs *regs); extern void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler); +extern void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries); extern int after_bootmem; extern __ro_after_init struct mm_struct *poking_mm; extern __ro_after_init unsigned long poking_addr; diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 390596b761e3..bd542f9b0953 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -14,6 +14,7 @@ #include <linux/kdebug.h> #include <linux/kprobes.h> #include <linux/mmu_context.h> +#include <linux/bsearch.h> #include <asm/text-patching.h> #include <asm/alternative.h> #include <asm/sections.h> @@ -848,81 +849,133 @@ static void do_sync_core(void *info) sync_core(); } -static bool bp_patching_in_progress; -static void *bp_int3_handler, *bp_int3_addr; +static struct bp_patching_desc { + struct text_poke_loc *vec; + int nr_entries; +} bp_patching; + +static int patch_cmp(const void *key, const void *elt) +{ + struct text_poke_loc *tp = (struct text_poke_loc *) elt; + + if (key < tp->addr) + return -1; + if (key > tp->addr) + return 1; + return 0; +} +NOKPROBE_SYMBOL(patch_cmp); int poke_int3_handler(struct pt_regs *regs) { + struct text_poke_loc *tp; + unsigned char int3 = 0xcc; + void *ip; + /* * Having observed our INT3 instruction, we now must observe - * bp_patching_in_progress. + * bp_patching.nr_entries. * - * in_progress = TRUE INT3 + * nr_entries != 0 INT3 * WMB RMB - * write INT3 if (in_progress) + * write INT3 if (nr_entries) * - * Idem for bp_int3_handler. + * Idem for other elements in bp_patching. */ smp_rmb(); - if (likely(!bp_patching_in_progress)) + if (likely(!bp_patching.nr_entries)) return 0; - if (user_mode(regs) || regs->ip != (unsigned long)bp_int3_addr) + if (user_mode(regs)) return 0; - /* set up the specified breakpoint handler */ - regs->ip = (unsigned long) bp_int3_handler; + /* + * Discount the sizeof(int3). See text_poke_bp_batch(). + */ + ip = (void *) regs->ip - sizeof(int3); + + /* + * Skip the binary search if there is a single member in the vector. + */ + if (unlikely(bp_patching.nr_entries > 1)) { + tp = bsearch(ip, bp_patching.vec, bp_patching.nr_entries, + sizeof(struct text_poke_loc), + patch_cmp); + if (!tp) + return 0; + } else { + tp = bp_patching.vec; + if (tp->addr != ip) + return 0; + } + + /* set up the specified breakpoint detour */ + regs->ip = (unsigned long) tp->detour; return 1; } NOKPROBE_SYMBOL(poke_int3_handler); /** - * text_poke_bp() -- update instructions on live kernel on SMP - * @addr: address to patch - * @opcode: opcode of new instruction - * @len: length to copy - * @handler: address to jump to when the temporary breakpoint is hit + * text_poke_bp_batch() -- update instructions on live kernel on SMP + * @tp: vector of instructions to patch + * @nr_entries: number of entries in the vector * * Modify multi-byte instruction by using int3 breakpoint on SMP. * We completely avoid stop_machine() here, and achieve the * synchronization using int3 breakpoint. * * The way it is done: - * - add a int3 trap to the address that will be patched + * - For each entry in the vector: + * - add a int3 trap to the address that will be patched * - sync cores - * - update all but the first byte of the patched range + * - For each entry in the vector: + * - update all but the first byte of the patched range * - sync cores - * - replace the first byte (int3) by the first byte of - * replacing opcode + * - For each entry in the vector: + * - replace the first byte (int3) by the first byte of + * replacing opcode * - sync cores */ -void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler) +void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries) { + int patched_all_but_first = 0; unsigned char int3 = 0xcc; - - bp_int3_handler = handler; - bp_int3_addr = (u8 *)addr + sizeof(int3); - bp_patching_in_progress = true; + unsigned int i; lockdep_assert_held(&text_mutex); + bp_patching.vec = tp; + bp_patching.nr_entries = nr_entries; + /* * Corresponding read barrier in int3 notifier for making sure the - * in_progress and handler are correctly ordered wrt. patching. + * nr_entries and handler are correctly ordered wrt. patching. */ smp_wmb(); - text_poke(addr, &int3, sizeof(int3)); + /* + * First step: add a int3 trap to the address that will be patched. + */ + for (i = 0; i < nr_entries; i++) + text_poke(tp[i].addr, &int3, sizeof(int3)); on_each_cpu(do_sync_core, NULL, 1); - if (len - sizeof(int3) > 0) { - /* patch all but the first byte */ - text_poke((char *)addr + sizeof(int3), - (const char *) opcode + sizeof(int3), - len - sizeof(int3)); + /* + * Second step: update all but the first byte of the patched range. + */ + for (i = 0; i < nr_entries; i++) { + if (tp[i].len - sizeof(int3) > 0) { + text_poke((char *)tp[i].addr + sizeof(int3), + (const char *)tp[i].opcode + sizeof(int3), + tp[i].len - sizeof(int3)); + patched_all_but_first++; + } + } + + if (patched_all_but_first) { /* * According to Intel, this core syncing is very likely * not necessary and we'd be safe even without it. But @@ -931,14 +984,47 @@ void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler) on_each_cpu(do_sync_core, NULL, 1); } - /* patch the first byte */ - text_poke(addr, opcode, sizeof(int3)); + /* + * Third step: replace the first byte (int3) by the first byte of + * replacing opcode. + */ + for (i = 0; i < nr_entries; i++) + text_poke(tp[i].addr, tp[i].opcode, sizeof(int3)); on_each_cpu(do_sync_core, NULL, 1); /* * sync_core() implies an smp_mb() and orders this store against * the writing of the new instruction. */ - bp_patching_in_progress = false; + bp_patching.vec = NULL; + bp_patching.nr_entries = 0; } +/** + * text_poke_bp() -- update instructions on live kernel on SMP + * @addr: address to patch + * @opcode: opcode of new instruction + * @len: length to copy + * @handler: address to jump to when the temporary breakpoint is hit + * + * Update a single instruction with the vector in the stack, avoiding + * dynamically allocated memory. This function should be used when it is + * not possible to allocate memory. + */ +void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler) +{ + struct text_poke_loc tp = { + .detour = handler, + .addr = addr, + .len = len, + }; + + if (len > POKE_MAX_OPCODE_SIZE) { + WARN_ONCE(1, "len is larger than %d\n", POKE_MAX_OPCODE_SIZE); + return; + } + + memcpy((void *)tp.opcode, opcode, len); + + text_poke_bp_batch(&tp, 1); +} diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index e631c358f7f4..044053235302 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -35,41 +35,43 @@ static void bug_at(unsigned char *ip, int line) BUG(); } -static void __ref __jump_label_transform(struct jump_entry *entry, - enum jump_label_type type, - int init) +static void __jump_label_set_jump_code(struct jump_entry *entry, + enum jump_label_type type, + union jump_code_union *code, + int init) { - union jump_code_union jmp; const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5]; - const void *expect, *code; + const void *expect; int line; - jmp.jump = 0xe9; - jmp.offset = jump_entry_target(entry) - - (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); + code->jump = 0xe9; + code->offset = jump_entry_target(entry) - + (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); - if (type == JUMP_LABEL_JMP) { - if (init) { - expect = default_nop; line = __LINE__; - } else { - expect = ideal_nop; line = __LINE__; - } - - code = &jmp.code; + if (init) { + expect = default_nop; line = __LINE__; + } else if (type == JUMP_LABEL_JMP) { + expect = ideal_nop; line = __LINE__; } else { - if (init) { - expect = default_nop; line = __LINE__; - } else { - expect = &jmp.code; line = __LINE__; - } - - code = ideal_nop; + expect = code->code; line = __LINE__; } if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE)) bug_at((void *)jump_entry_code(entry), line); + if (type == JUMP_LABEL_NOP) + memcpy(code, ideal_nop, JUMP_LABEL_NOP_SIZE); +} + +static void __ref __jump_label_transform(struct jump_entry *entry, + enum jump_label_type type, + int init) +{ + union jump_code_union code; + + __jump_label_set_jump_code(entry, type, &code, init); + /* * As long as only a single processor is running and the code is still * not marked as RO, text_poke_early() can be used; Checking that @@ -82,12 +84,12 @@ static void __ref __jump_label_transform(struct jump_entry *entry, * always nop being the 'currently valid' instruction */ if (init || system_state == SYSTEM_BOOTING) { - text_poke_early((void *)jump_entry_code(entry), code, + text_poke_early((void *)jump_entry_code(entry), &code, JUMP_LABEL_NOP_SIZE); return; } - text_poke_bp((void *)jump_entry_code(entry), code, JUMP_LABEL_NOP_SIZE, + text_poke_bp((void *)jump_entry_code(entry), &code, JUMP_LABEL_NOP_SIZE, (void *)jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); } @@ -99,6 +101,75 @@ void arch_jump_label_transform(struct jump_entry *entry, mutex_unlock(&text_mutex); } +#define TP_VEC_MAX (PAGE_SIZE / sizeof(struct text_poke_loc)) +static struct text_poke_loc tp_vec[TP_VEC_MAX]; +static int tp_vec_nr; + +bool arch_jump_label_transform_queue(struct jump_entry *entry, + enum jump_label_type type) +{ + struct text_poke_loc *tp; + void *entry_code; + + if (system_state == SYSTEM_BOOTING) { + /* + * Fallback to the non-batching mode. + */ + arch_jump_label_transform(entry, type); + return true; + } + + /* + * No more space in the vector, tell upper layer to apply + * the queue before continuing. + */ + if (tp_vec_nr == TP_VEC_MAX) + return false; + + tp = &tp_vec[tp_vec_nr]; + + entry_code = (void *)jump_entry_code(entry); + + /* + * The INT3 handler will do a bsearch in the queue, so we need entries + * to be sorted. We can survive an unsorted list by rejecting the entry, + * forcing the generic jump_label code to apply the queue. Warning once, + * to raise the attention to the case of an unsorted entry that is + * better not happen, because, in the worst case we will perform in the + * same way as we do without batching - with some more overhead. + */ + if (tp_vec_nr > 0) { + int prev = tp_vec_nr - 1; + struct text_poke_loc *prev_tp = &tp_vec[prev]; + + if (WARN_ON_ONCE(prev_tp->addr > entry_code)) + return false; + } + + __jump_label_set_jump_code(entry, type, + (union jump_code_union *) &tp->opcode, 0); + + tp->addr = entry_code; + tp->detour = entry_code + JUMP_LABEL_NOP_SIZE; + tp->len = JUMP_LABEL_NOP_SIZE; + + tp_vec_nr++; + + return true; +} + +void arch_jump_label_transform_apply(void) +{ + if (!tp_vec_nr) + return; + + mutex_lock(&text_mutex); + text_poke_bp_batch(tp_vec, tp_vec_nr); + mutex_unlock(&text_mutex); + + tp_vec_nr = 0; +} + static enum { JL_STATE_START, JL_STATE_NO_UPDATE, diff --git a/drivers/crypto/nx/nx-842-pseries.c b/drivers/crypto/nx/nx-842-pseries.c index 5c4aa606208c..2de5e3672e42 100644 --- a/drivers/crypto/nx/nx-842-pseries.c +++ b/drivers/crypto/nx/nx-842-pseries.c @@ -856,7 +856,7 @@ static ssize_t nx842_##_name##_show(struct device *dev, \ rcu_read_lock(); \ local_devdata = rcu_dereference(devdata); \ if (local_devdata) \ - p = snprintf(buf, PAGE_SIZE, "%ld\n", \ + p = snprintf(buf, PAGE_SIZE, "%lld\n", \ atomic64_read(&local_devdata->counters->_name)); \ rcu_read_unlock(); \ return p; \ @@ -909,7 +909,7 @@ static ssize_t nx842_timehist_show(struct device *dev, } for (i = 0; i < (NX842_HIST_SLOTS - 2); i++) { - bytes = snprintf(p, bytes_remain, "%u-%uus:\t%ld\n", + bytes = snprintf(p, bytes_remain, "%u-%uus:\t%lld\n", i ? (2<<(i-1)) : 0, (2<<i)-1, atomic64_read(×[i])); bytes_remain -= bytes; @@ -917,7 +917,7 @@ static ssize_t nx842_timehist_show(struct device *dev, } /* The last bucket holds everything over * 2<<(NX842_HIST_SLOTS - 2) us */ - bytes = snprintf(p, bytes_remain, "%uus - :\t%ld\n", + bytes = snprintf(p, bytes_remain, "%uus - :\t%lld\n", 2<<(NX842_HIST_SLOTS - 2), atomic64_read(×[(NX842_HIST_SLOTS - 1)])); p += bytes; diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c index 29f7b15c81d9..d020bb4d03d5 100644 --- a/drivers/infiniband/core/device.c +++ b/drivers/infiniband/core/device.c @@ -457,7 +457,7 @@ static int alloc_name(struct ib_device *ibdev, const char *name) int rc; int i; - lockdep_assert_held_exclusive(&devices_rwsem); + lockdep_assert_held_write(&devices_rwsem); ida_init(&inuse); xa_for_each (&devices, index, device) { char buf[IB_DEVICE_NAME_MAX]; diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index e38f104db174..fde8d4073e74 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -487,7 +487,7 @@ static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld) static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld) { - lockdep_assert_held_exclusive(&tty->ldisc_sem); + lockdep_assert_held_write(&tty->ldisc_sem); WARN_ON(!test_bit(TTY_LDISC_OPEN, &tty->flags)); clear_bit(TTY_LDISC_OPEN, &tty->flags); if (ld->ops->close) @@ -509,7 +509,7 @@ static int tty_ldisc_failto(struct tty_struct *tty, int ld) struct tty_ldisc *disc = tty_ldisc_get(tty, ld); int r; - lockdep_assert_held_exclusive(&tty->ldisc_sem); + lockdep_assert_held_write(&tty->ldisc_sem); if (IS_ERR(disc)) return PTR_ERR(disc); tty->ldisc = disc; @@ -633,7 +633,7 @@ EXPORT_SYMBOL_GPL(tty_set_ldisc); */ static void tty_ldisc_kill(struct tty_struct *tty) { - lockdep_assert_held_exclusive(&tty->ldisc_sem); + lockdep_assert_held_write(&tty->ldisc_sem); if (!tty->ldisc) return; /* @@ -681,7 +681,7 @@ int tty_ldisc_reinit(struct tty_struct *tty, int disc) struct tty_ldisc *ld; int retval; - lockdep_assert_held_exclusive(&tty->ldisc_sem); + lockdep_assert_held_write(&tty->ldisc_sem); ld = tty_ldisc_get(tty, disc); if (IS_ERR(ld)) { BUG_ON(disc == N_TTY); @@ -1187,7 +1187,7 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, unsigned flags = 0; if (iov_iter_rw(iter) == WRITE) { - lockdep_assert_held_exclusive(&inode->i_rwsem); + lockdep_assert_held_write(&inode->i_rwsem); flags |= IOMAP_WRITE; } else { lockdep_assert_held(&inode->i_rwsem); diff --git a/include/asm-generic/atomic64.h b/include/asm-generic/atomic64.h index d7a15096fb3b..370f01d4450f 100644 --- a/include/asm-generic/atomic64.h +++ b/include/asm-generic/atomic64.h @@ -10,24 +10,24 @@ #include <linux/types.h> typedef struct { - long long counter; + s64 counter; } atomic64_t; #define ATOMIC64_INIT(i) { (i) } -extern long long atomic64_read(const atomic64_t *v); -extern void atomic64_set(atomic64_t *v, long long i); +extern s64 atomic64_read(const atomic64_t *v); +extern void atomic64_set(atomic64_t *v, s64 i); #define atomic64_set_release(v, i) atomic64_set((v), (i)) #define ATOMIC64_OP(op) \ -extern void atomic64_##op(long long a, atomic64_t *v); +extern void atomic64_##op(s64 a, atomic64_t *v); #define ATOMIC64_OP_RETURN(op) \ -extern long long atomic64_##op##_return(long long a, atomic64_t *v); +extern s64 atomic64_##op##_return(s64 a, atomic64_t *v); #define ATOMIC64_FETCH_OP(op) \ -extern long long atomic64_fetch_##op(long long a, atomic64_t *v); +extern s64 atomic64_fetch_##op(s64 a, atomic64_t *v); #define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op) ATOMIC64_FETCH_OP(op) @@ -46,11 +46,11 @@ ATOMIC64_OPS(xor) #undef ATOMIC64_OP_RETURN #undef ATOMIC64_OP -extern long long atomic64_dec_if_positive(atomic64_t *v); +extern s64 atomic64_dec_if_positive(atomic64_t *v); #define atomic64_dec_if_positive atomic64_dec_if_positive -extern long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n); -extern long long atomic64_xchg(atomic64_t *v, long long new); -extern long long atomic64_fetch_add_unless(atomic64_t *v, long long a, long long u); +extern s64 atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n); +extern s64 atomic64_xchg(atomic64_t *v, s64 new); +extern s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u); #define atomic64_fetch_add_unless atomic64_fetch_add_unless #endif /* _ASM_GENERIC_ATOMIC64_H */ diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index 3e113a1fa0f1..3526c0aee954 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -215,6 +215,9 @@ extern void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type); extern void arch_jump_label_transform_static(struct jump_entry *entry, enum jump_label_type type); +extern bool arch_jump_label_transform_queue(struct jump_entry *entry, + enum jump_label_type type); +extern void arch_jump_label_transform_apply(void); extern int jump_label_text_reserved(void *start, void *end); extern void static_key_slow_inc(struct static_key *key); extern void static_key_slow_dec(struct static_key *key); diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index e8eef38b2213..57baa27f238c 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -203,11 +203,17 @@ struct lock_list { struct lock_list *parent; }; -/* - * We record lock dependency chains, so that we can cache them: +/** + * struct lock_chain - lock dependency chain record + * + * @irq_context: the same as irq_context in held_lock below + * @depth: the number of held locks in this chain + * @base: the index in chain_hlocks for this chain + * @entry: the collided lock chains in lock_chain hash list + * @chain_key: the hash key of this lock_chain */ struct lock_chain { - /* see BUILD_BUG_ON()s in lookup_chain_cache() */ + /* see BUILD_BUG_ON()s in add_chain_cache() */ unsigned int irq_context : 2, depth : 6, base : 24; @@ -217,12 +223,8 @@ struct lock_chain { }; #define MAX_LOCKDEP_KEYS_BITS 13 -/* - * Subtract one because we offset hlock->class_idx by 1 in order - * to make 0 mean no class. This avoids overflowing the class_idx - * bitfield and hitting the BUG in hlock_class(). - */ -#define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1) +#define MAX_LOCKDEP_KEYS (1UL << MAX_LOCKDEP_KEYS_BITS) +#define INITIAL_CHAIN_KEY -1 struct held_lock { /* @@ -247,6 +249,11 @@ struct held_lock { u64 waittime_stamp; u64 holdtime_stamp; #endif + /* + * class_idx is zero-indexed; it points to the element in + * lock_classes this held lock instance belongs to. class_idx is in + * the range from 0 to (MAX_LOCKDEP_KEYS-1) inclusive. + */ unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS; /* * The lock-stack is unified in that the lock chains of interrupt @@ -281,6 +288,8 @@ extern void lockdep_free_key_range(void *start, unsigned long size); extern asmlinkage void lockdep_sys_exit(void); extern void lockdep_set_selftest_task(struct task_struct *task); +extern void lockdep_init_task(struct task_struct *task); + extern void lockdep_off(void); extern void lockdep_on(void); @@ -385,7 +394,7 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); WARN_ON(debug_locks && !lockdep_is_held(l)); \ } while (0) -#define lockdep_assert_held_exclusive(l) do { \ +#define lockdep_assert_held_write(l) do { \ WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \ } while (0) @@ -405,6 +414,10 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); #else /* !CONFIG_LOCKDEP */ +static inline void lockdep_init_task(struct task_struct *task) +{ +} + static inline void lockdep_off(void) { } @@ -466,7 +479,7 @@ struct lockdep_map { }; #define lockdep_is_held_type(l, r) (1) #define lockdep_assert_held(l) do { (void)(l); } while (0) -#define lockdep_assert_held_exclusive(l) do { (void)(l); } while (0) +#define lockdep_assert_held_write(l) do { (void)(l); } while (0) #define lockdep_assert_held_read(l) do { (void)(l); } while (0) #define lockdep_assert_held_once(l) do { (void)(l); } while (0) @@ -497,7 +510,6 @@ enum xhlock_context_t { { .name = (_name), .key = (void *)(_key), } static inline void lockdep_invariant_state(bool force) {} -static inline void lockdep_init_task(struct task_struct *task) {} static inline void lockdep_free_task(struct task_struct *task) {} #ifdef CONFIG_LOCK_STAT diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index 2809b44cbbee..3998cdf9cd14 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -121,7 +121,7 @@ static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem, lock_release(&sem->rw_sem.dep_map, 1, ip); #ifdef CONFIG_RWSEM_SPIN_ON_OWNER if (!read) - sem->rw_sem.owner = RWSEM_OWNER_UNKNOWN; + atomic_long_set(&sem->rw_sem.owner, RWSEM_OWNER_UNKNOWN); #endif } @@ -131,7 +131,7 @@ static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem, lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip); #ifdef CONFIG_RWSEM_SPIN_ON_OWNER if (!read) - sem->rw_sem.owner = current; + atomic_long_set(&sem->rw_sem.owner, (long)current); #endif } diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 2ea18a3def04..e401358c4e7e 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -34,12 +34,13 @@ */ struct rw_semaphore { atomic_long_t count; -#ifdef CONFIG_RWSEM_SPIN_ON_OWNER /* - * Write owner. Used as a speculative check to see - * if the owner is running on the cpu. + * Write owner or one of the read owners as well flags regarding + * the current state of the rwsem. Can be used as a speculative + * check to see if the write owner is running on the cpu. */ - struct task_struct *owner; + atomic_long_t owner; +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER struct optimistic_spin_queue osq; /* spinner MCS lock */ #endif raw_spinlock_t wait_lock; @@ -50,10 +51,10 @@ struct rw_semaphore { }; /* - * Setting bit 1 of the owner field but not bit 0 will indicate + * Setting all bits of the owner field except bit 0 will indicate * that the rwsem is writer-owned with an unknown owner. */ -#define RWSEM_OWNER_UNKNOWN ((struct task_struct *)-2L) +#define RWSEM_OWNER_UNKNOWN (-2L) /* In all implementations count != 0 means locked */ static inline int rwsem_is_locked(struct rw_semaphore *sem) @@ -73,13 +74,14 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem) #endif #ifdef CONFIG_RWSEM_SPIN_ON_OWNER -#define __RWSEM_OPT_INIT(lockname) , .osq = OSQ_LOCK_UNLOCKED, .owner = NULL +#define __RWSEM_OPT_INIT(lockname) , .osq = OSQ_LOCK_UNLOCKED #else #define __RWSEM_OPT_INIT(lockname) #endif #define __RWSEM_INITIALIZER(name) \ { __RWSEM_INIT_COUNT(name), \ + .owner = ATOMIC_LONG_INIT(0), \ .wait_list = LIST_HEAD_INIT((name).wait_list), \ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock) \ __RWSEM_OPT_INIT(name) \ diff --git a/include/linux/sched/wake_q.h b/include/linux/sched/wake_q.h index ad826d2a4557..26a2013ac39c 100644 --- a/include/linux/sched/wake_q.h +++ b/include/linux/sched/wake_q.h @@ -51,6 +51,11 @@ static inline void wake_q_init(struct wake_q_head *head) head->lastp = &head->first; } +static inline bool wake_q_empty(struct wake_q_head *head) +{ + return head->first == WAKE_Q_TAIL; +} + extern void wake_q_add(struct wake_q_head *head, struct task_struct *task); extern void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task); extern void wake_up_q(struct wake_q_head *head); diff --git a/include/linux/smp.h b/include/linux/smp.h index bb8b451ab01f..6fc856c9eda5 100644 --- a/include/linux/smp.h +++ b/include/linux/smp.h @@ -180,29 +180,46 @@ static inline int get_boot_cpu_id(void) #endif /* !SMP */ -/* - * smp_processor_id(): get the current CPU ID. +/** + * raw_processor_id() - get the current (unstable) CPU id + * + * For then you know what you are doing and need an unstable + * CPU id. + */ + +/** + * smp_processor_id() - get the current (stable) CPU id + * + * This is the normal accessor to the CPU id and should be used + * whenever possible. + * + * The CPU id is stable when: * - * if DEBUG_PREEMPT is enabled then we check whether it is - * used in a preemption-safe way. (smp_processor_id() is safe - * if it's used in a preemption-off critical section, or in - * a thread that is bound to the current CPU.) + * - IRQs are disabled; + * - preemption is disabled; + * - the task is CPU affine. * - * NOTE: raw_smp_processor_id() is for internal use only - * (smp_processor_id() is the preferred variant), but in rare - * instances it might also be used to turn off false positives - * (i.e. smp_processor_id() use that the debugging code reports but - * which use for some reason is legal). Don't use this to hack around - * the warning message, as your code might not work under PREEMPT. + * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN + * when smp_processor_id() is used when the CPU id is not stable. */ + +/* + * Allow the architecture to differentiate between a stable and unstable read. + * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a + * regular asm read for the stable. + */ +#ifndef __smp_processor_id +#define __smp_processor_id(x) raw_smp_processor_id(x) +#endif + #ifdef CONFIG_DEBUG_PREEMPT extern unsigned int debug_smp_processor_id(void); # define smp_processor_id() debug_smp_processor_id() #else -# define smp_processor_id() raw_smp_processor_id() +# define smp_processor_id() __smp_processor_id() #endif -#define get_cpu() ({ preempt_disable(); smp_processor_id(); }) +#define get_cpu() ({ preempt_disable(); __smp_processor_id(); }) #define put_cpu() preempt_enable() /* diff --git a/include/linux/types.h b/include/linux/types.h index 231114ae38f4..05030f608be3 100644 --- a/include/linux/types.h +++ b/include/linux/types.h @@ -174,7 +174,7 @@ typedef struct { #ifdef CONFIG_64BIT typedef struct { - long counter; + s64 counter; } atomic64_t; #endif diff --git a/init/init_task.c b/init/init_task.c index c70ef656d0f4..afa6ad795355 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -166,6 +166,8 @@ struct task_struct init_task .softirqs_enabled = 1, #endif #ifdef CONFIG_LOCKDEP + .lockdep_depth = 0, /* no locks held yet */ + .curr_chain_key = INITIAL_CHAIN_KEY, .lockdep_recursion = 0, #endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER diff --git a/kernel/fork.c b/kernel/fork.c index a83ef7243ccc..d18e343d4aab 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1952,9 +1952,6 @@ static __latent_entropy struct task_struct *copy_process( p->pagefault_disabled = 0; #ifdef CONFIG_LOCKDEP - p->lockdep_depth = 0; /* no locks held yet */ - p->curr_chain_key = 0; - p->lockdep_recursion = 0; lockdep_init_task(p); #endif diff --git a/kernel/futex.c b/kernel/futex.c index 4b5b468c58b6..6d50728ef2e7 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -471,6 +471,37 @@ enum futex_access { }; /** + * futex_setup_timer - set up the sleeping hrtimer. + * @time: ptr to the given timeout value + * @timeout: the hrtimer_sleeper structure to be set up + * @flags: futex flags + * @range_ns: optional range in ns + * + * Return: Initialized hrtimer_sleeper structure or NULL if no timeout + * value given + */ +static inline struct hrtimer_sleeper * +futex_setup_timer(ktime_t *time, struct hrtimer_sleeper *timeout, + int flags, u64 range_ns) +{ + if (!time) + return NULL; + + hrtimer_init_on_stack(&timeout->timer, (flags & FLAGS_CLOCKRT) ? + CLOCK_REALTIME : CLOCK_MONOTONIC, + HRTIMER_MODE_ABS); + hrtimer_init_sleeper(timeout, current); + + /* + * If range_ns is 0, calling hrtimer_set_expires_range_ns() is + * effectively the same as calling hrtimer_set_expires(). + */ + hrtimer_set_expires_range_ns(&timeout->timer, *time, range_ns); + + return timeout; +} + +/** * get_futex_key() - Get parameters which are the keys for a futex * @uaddr: virtual address of the futex * @fshared: 0 for a PROCESS_PRIVATE futex, 1 for PROCESS_SHARED @@ -2679,7 +2710,7 @@ out: static int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, ktime_t *abs_time, u32 bitset) { - struct hrtimer_sleeper timeout, *to = NULL; + struct hrtimer_sleeper timeout, *to; struct restart_block *restart; struct futex_hash_bucket *hb; struct futex_q q = futex_q_init; @@ -2689,17 +2720,8 @@ static int futex_wait(u32 __user *uaddr, unsigned int flags, u32 val, return -EINVAL; q.bitset = bitset; - if (abs_time) { - to = &timeout; - - hrtimer_init_on_stack(&to->timer, (flags & FLAGS_CLOCKRT) ? - CLOCK_REALTIME : CLOCK_MONOTONIC, - HRTIMER_MODE_ABS); - hrtimer_init_sleeper(to, current); - hrtimer_set_expires_range_ns(&to->timer, *abs_time, - current->timer_slack_ns); - } - + to = futex_setup_timer(abs_time, &timeout, flags, + current->timer_slack_ns); retry: /* * Prepare to wait on uaddr. On success, holds hb lock and increments @@ -2779,7 +2801,7 @@ static long futex_wait_restart(struct restart_block *restart) static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *time, int trylock) { - struct hrtimer_sleeper timeout, *to = NULL; + struct hrtimer_sleeper timeout, *to; struct futex_pi_state *pi_state = NULL; struct rt_mutex_waiter rt_waiter; struct futex_hash_bucket *hb; @@ -2792,13 +2814,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, if (refill_pi_state_cache()) return -ENOMEM; - if (time) { - to = &timeout; - hrtimer_init_on_stack(&to->timer, CLOCK_REALTIME, - HRTIMER_MODE_ABS); - hrtimer_init_sleeper(to, current); - hrtimer_set_expires(&to->timer, *time); - } + to = futex_setup_timer(time, &timeout, FLAGS_CLOCKRT, 0); retry: ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key, FUTEX_WRITE); @@ -3195,7 +3211,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, u32 val, ktime_t *abs_time, u32 bitset, u32 __user *uaddr2) { - struct hrtimer_sleeper timeout, *to = NULL; + struct hrtimer_sleeper timeout, *to; struct futex_pi_state *pi_state = NULL; struct rt_mutex_waiter rt_waiter; struct futex_hash_bucket *hb; @@ -3212,15 +3228,8 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags, if (!bitset) return -EINVAL; - if (abs_time) { - to = &timeout; - hrtimer_init_on_stack(&to->timer, (flags & FLAGS_CLOCKRT) ? - CLOCK_REALTIME : CLOCK_MONOTONIC, - HRTIMER_MODE_ABS); - hrtimer_init_sleeper(to, current); - hrtimer_set_expires_range_ns(&to->timer, *abs_time, - current->timer_slack_ns); - } + to = futex_setup_timer(abs_time, &timeout, flags, + current->timer_slack_ns); /* * The waiter is allocated on our stack, manipulated by the requeue diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 0bfa10f4410c..df3008419a1d 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -37,12 +37,26 @@ static int jump_label_cmp(const void *a, const void *b) const struct jump_entry *jea = a; const struct jump_entry *jeb = b; + /* + * Entrires are sorted by key. + */ if (jump_entry_key(jea) < jump_entry_key(jeb)) return -1; if (jump_entry_key(jea) > jump_entry_key(jeb)) return 1; + /* + * In the batching mode, entries should also be sorted by the code + * inside the already sorted list of entries, enabling a bsearch in + * the vector. + */ + if (jump_entry_code(jea) < jump_entry_code(jeb)) + return -1; + + if (jump_entry_code(jea) > jump_entry_code(jeb)) + return 1; + return 0; } @@ -384,25 +398,55 @@ static enum jump_label_type jump_label_type(struct jump_entry *entry) return enabled ^ branch; } +static bool jump_label_can_update(struct jump_entry *entry, bool init) +{ + /* + * Cannot update code that was in an init text area. + */ + if (!init && jump_entry_is_init(entry)) + return false; + + if (!kernel_text_address(jump_entry_code(entry))) { + WARN_ONCE(1, "can't patch jump_label at %pS", (void *)jump_entry_code(entry)); + return false; + } + + return true; +} + +#ifndef HAVE_JUMP_LABEL_BATCH static void __jump_label_update(struct static_key *key, struct jump_entry *entry, struct jump_entry *stop, bool init) { for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) { - /* - * An entry->code of 0 indicates an entry which has been - * disabled because it was in an init text area. - */ - if (init || !jump_entry_is_init(entry)) { - if (kernel_text_address(jump_entry_code(entry))) - arch_jump_label_transform(entry, jump_label_type(entry)); - else - WARN_ONCE(1, "can't patch jump_label at %pS", - (void *)jump_entry_code(entry)); + if (jump_label_can_update(entry, init)) + arch_jump_label_transform(entry, jump_label_type(entry)); + } +} +#else +static void __jump_label_update(struct static_key *key, + struct jump_entry *entry, + struct jump_entry *stop, + bool init) +{ + for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) { + + if (!jump_label_can_update(entry, init)) + continue; + + if (!arch_jump_label_transform_queue(entry, jump_label_type(entry))) { + /* + * Queue is full: Apply the current queue and try again. + */ + arch_jump_label_transform_apply(); + BUG_ON(!arch_jump_label_transform_queue(entry, jump_label_type(entry))); } } + arch_jump_label_transform_apply(); } +#endif void __init jump_label_init(void) { diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile index 6fe2f333aecb..45452facff3b 100644 --- a/kernel/locking/Makefile +++ b/kernel/locking/Makefile @@ -3,7 +3,7 @@ # and is generally not a function of system call inputs. KCOV_INSTRUMENT := n -obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o rwsem-xadd.o +obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE) diff --git a/kernel/locking/lock_events.h b/kernel/locking/lock_events.h index 46b71af8eef2..8c7e7d25f09c 100644 --- a/kernel/locking/lock_events.h +++ b/kernel/locking/lock_events.h @@ -31,50 +31,13 @@ enum lock_events { DECLARE_PER_CPU(unsigned long, lockevents[lockevent_num]); /* - * The purpose of the lock event counting subsystem is to provide a low - * overhead way to record the number of specific locking events by using - * percpu counters. It is the percpu sum that matters, not specifically - * how many of them happens in each cpu. - * - * It is possible that the same percpu counter may be modified in both - * the process and interrupt contexts. For architectures that perform - * percpu operation with multiple instructions, it is possible to lose - * count if a process context percpu update is interrupted in the middle - * and the same counter is updated in the interrupt context. Therefore, - * the generated percpu sum may not be precise. The error, if any, should - * be small and insignificant. - * - * For those architectures that do multi-instruction percpu operation, - * preemption in the middle and moving the task to another cpu may cause - * a larger error in the count. Again, this will be few and far between. - * Given the imprecise nature of the count and the possibility of resetting - * the count and doing the measurement again, this is not really a big - * problem. - * - * To get a better picture of what is happening under the hood, it is - * suggested that a few measurements should be taken with the counts - * reset in between to stamp out outliner because of these possible - * error conditions. - * - * To minimize overhead, we use __this_cpu_*() in all cases except when - * CONFIG_DEBUG_PREEMPT is defined. In this particular case, this_cpu_*() - * will be used to avoid the appearance of unwanted BUG messages. - */ -#ifdef CONFIG_DEBUG_PREEMPT -#define lockevent_percpu_inc(x) this_cpu_inc(x) -#define lockevent_percpu_add(x, v) this_cpu_add(x, v) -#else -#define lockevent_percpu_inc(x) __this_cpu_inc(x) -#define lockevent_percpu_add(x, v) __this_cpu_add(x, v) -#endif - -/* - * Increment the PV qspinlock statistical counters + * Increment the statistical counters. use raw_cpu_inc() because of lower + * overhead and we don't care if we loose the occasional update. */ static inline void __lockevent_inc(enum lock_events event, bool cond) { if (cond) - lockevent_percpu_inc(lockevents[event]); + raw_cpu_inc(lockevents[event]); } #define lockevent_inc(ev) __lockevent_inc(LOCKEVENT_ ##ev, true) @@ -82,7 +45,7 @@ static inline void __lockevent_inc(enum lock_events event, bool cond) static inline void __lockevent_add(enum lock_events event, int inc) { - lockevent_percpu_add(lockevents[event], inc); + raw_cpu_add(lockevents[event], inc); } #define lockevent_add(ev, c) __lockevent_add(LOCKEVENT_ ##ev, c) diff --git a/kernel/locking/lock_events_list.h b/kernel/locking/lock_events_list.h index ad7668cfc9da..239039d0ce21 100644 --- a/kernel/locking/lock_events_list.h +++ b/kernel/locking/lock_events_list.h @@ -56,12 +56,16 @@ LOCK_EVENT(rwsem_sleep_reader) /* # of reader sleeps */ LOCK_EVENT(rwsem_sleep_writer) /* # of writer sleeps */ LOCK_EVENT(rwsem_wake_reader) /* # of reader wakeups */ LOCK_EVENT(rwsem_wake_writer) /* # of writer wakeups */ -LOCK_EVENT(rwsem_opt_wlock) /* # of write locks opt-spin acquired */ -LOCK_EVENT(rwsem_opt_fail) /* # of failed opt-spinnings */ +LOCK_EVENT(rwsem_opt_rlock) /* # of opt-acquired read locks */ +LOCK_EVENT(rwsem_opt_wlock) /* # of opt-acquired write locks */ +LOCK_EVENT(rwsem_opt_fail) /* # of failed optspins */ +LOCK_EVENT(rwsem_opt_nospin) /* # of disabled optspins */ +LOCK_EVENT(rwsem_opt_norspin) /* # of disabled reader-only optspins */ +LOCK_EVENT(rwsem_opt_rlock2) /* # of opt-acquired 2ndary read locks */ LOCK_EVENT(rwsem_rlock) /* # of read locks acquired */ LOCK_EVENT(rwsem_rlock_fast) /* # of fast read locks acquired */ LOCK_EVENT(rwsem_rlock_fail) /* # of failed read lock acquisitions */ -LOCK_EVENT(rwsem_rtrylock) /* # of read trylock calls */ +LOCK_EVENT(rwsem_rlock_handoff) /* # of read lock handoffs */ LOCK_EVENT(rwsem_wlock) /* # of write locks acquired */ LOCK_EVENT(rwsem_wlock_fail) /* # of failed write lock acquisitions */ -LOCK_EVENT(rwsem_wtrylock) /* # of write trylock calls */ +LOCK_EVENT(rwsem_wlock_handoff) /* # of write lock handoffs */ diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index c47788fa85f9..341f52117f88 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -151,17 +151,28 @@ unsigned long nr_lock_classes; static #endif struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; +static DECLARE_BITMAP(lock_classes_in_use, MAX_LOCKDEP_KEYS); static inline struct lock_class *hlock_class(struct held_lock *hlock) { - if (!hlock->class_idx) { + unsigned int class_idx = hlock->class_idx; + + /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfield */ + barrier(); + + if (!test_bit(class_idx, lock_classes_in_use)) { /* * Someone passed in garbage, we give up. */ DEBUG_LOCKS_WARN_ON(1); return NULL; } - return lock_classes + hlock->class_idx - 1; + + /* + * At this point, if the passed hlock->class_idx is still garbage, + * we just have to live with it + */ + return lock_classes + class_idx; } #ifdef CONFIG_LOCK_STAT @@ -359,6 +370,13 @@ static inline u64 iterate_chain_key(u64 key, u32 idx) return k0 | (u64)k1 << 32; } +void lockdep_init_task(struct task_struct *task) +{ + task->lockdep_depth = 0; /* no locks held yet */ + task->curr_chain_key = INITIAL_CHAIN_KEY; + task->lockdep_recursion = 0; +} + void lockdep_off(void) { current->lockdep_recursion++; @@ -419,13 +437,6 @@ static int verbose(struct lock_class *class) return 0; } -/* - * Stack-trace: tightly packed array of stack backtrace - * addresses. Protected by the graph_lock. - */ -unsigned long nr_stack_trace_entries; -static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; - static void print_lockdep_off(const char *bug_msg) { printk(KERN_DEBUG "%s\n", bug_msg); @@ -435,6 +446,15 @@ static void print_lockdep_off(const char *bug_msg) #endif } +unsigned long nr_stack_trace_entries; + +#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) +/* + * Stack-trace: tightly packed array of stack backtrace + * addresses. Protected by the graph_lock. + */ +static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; + static int save_trace(struct lock_trace *trace) { unsigned long *entries = stack_trace + nr_stack_trace_entries; @@ -457,6 +477,7 @@ static int save_trace(struct lock_trace *trace) return 1; } +#endif unsigned int nr_hardirq_chains; unsigned int nr_softirq_chains; @@ -470,6 +491,7 @@ unsigned int max_lockdep_depth; DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); #endif +#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) /* * Locking printouts: */ @@ -487,6 +509,7 @@ static const char *usage_str[] = #undef LOCKDEP_STATE [LOCK_USED] = "INITIAL USE", }; +#endif const char * __get_key_name(struct lockdep_subclass_key *key, char *str) { @@ -500,15 +523,26 @@ static inline unsigned long lock_flag(enum lock_usage_bit bit) static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) { + /* + * The usage character defaults to '.' (i.e., irqs disabled and not in + * irq context), which is the safest usage category. + */ char c = '.'; - if (class->usage_mask & lock_flag(bit + LOCK_USAGE_DIR_MASK)) + /* + * The order of the following usage checks matters, which will + * result in the outcome character as follows: + * + * - '+': irq is enabled and not in irq context + * - '-': in irq context and irq is disabled + * - '?': in irq context and irq is enabled + */ + if (class->usage_mask & lock_flag(bit + LOCK_USAGE_DIR_MASK)) { c = '+'; - if (class->usage_mask & lock_flag(bit)) { - c = '-'; - if (class->usage_mask & lock_flag(bit + LOCK_USAGE_DIR_MASK)) + if (class->usage_mask & lock_flag(bit)) c = '?'; - } + } else if (class->usage_mask & lock_flag(bit)) + c = '-'; return c; } @@ -572,19 +606,22 @@ static void print_lock(struct held_lock *hlock) /* * We can be called locklessly through debug_show_all_locks() so be * extra careful, the hlock might have been released and cleared. + * + * If this indeed happens, lets pretend it does not hurt to continue + * to print the lock unless the hlock class_idx does not point to a + * registered class. The rationale here is: since we don't attempt + * to distinguish whether we are in this situation, if it just + * happened we can't count on class_idx to tell either. */ - unsigned int class_idx = hlock->class_idx; - - /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfields: */ - barrier(); + struct lock_class *lock = hlock_class(hlock); - if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) { + if (!lock) { printk(KERN_CONT "<RELEASED>\n"); return; } printk(KERN_CONT "%p", hlock->instance); - print_lock_name(lock_classes + class_idx - 1); + print_lock_name(lock); printk(KERN_CONT ", at: %pS\n", (void *)hlock->acquire_ip); } @@ -732,7 +769,8 @@ look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass) * Huh! same key, different name? Did someone trample * on some memory? We're most confused. */ - WARN_ON_ONCE(class->name != lock->name); + WARN_ON_ONCE(class->name != lock->name && + lock->key != &__lockdep_no_validate__); return class; } } @@ -838,11 +876,11 @@ static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; static bool check_lock_chain_key(struct lock_chain *chain) { #ifdef CONFIG_PROVE_LOCKING - u64 chain_key = 0; + u64 chain_key = INITIAL_CHAIN_KEY; int i; for (i = chain->base; i < chain->base + chain->depth; i++) - chain_key = iterate_chain_key(chain_key, chain_hlocks[i] + 1); + chain_key = iterate_chain_key(chain_key, chain_hlocks[i]); /* * The 'unsigned long long' casts avoid that a compiler warning * is reported when building tools/lib/lockdep. @@ -1117,6 +1155,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) return NULL; } nr_lock_classes++; + __set_bit(class - lock_classes, lock_classes_in_use); debug_atomic_inc(nr_unused_locks); class->key = key; class->name = lock->name; @@ -1228,13 +1267,17 @@ static int add_lock_to_list(struct lock_class *this, #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) /* - * The circular_queue and helpers is used to implement the - * breadth-first search(BFS)algorithem, by which we can build - * the shortest path from the next lock to be acquired to the - * previous held lock if there is a circular between them. + * The circular_queue and helpers are used to implement graph + * breadth-first search (BFS) algorithm, by which we can determine + * whether there is a path from a lock to another. In deadlock checks, + * a path from the next lock to be acquired to a previous held lock + * indicates that adding the <prev> -> <next> lock dependency will + * produce a circle in the graph. Breadth-first search instead of + * depth-first search is used in order to find the shortest (circular) + * path. */ struct circular_queue { - unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; + struct lock_list *element[MAX_CIRCULAR_QUEUE_SIZE]; unsigned int front, rear; }; @@ -1260,7 +1303,7 @@ static inline int __cq_full(struct circular_queue *cq) return ((cq->rear + 1) & CQ_MASK) == cq->front; } -static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) +static inline int __cq_enqueue(struct circular_queue *cq, struct lock_list *elem) { if (__cq_full(cq)) return -1; @@ -1270,14 +1313,21 @@ static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) return 0; } -static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) +/* + * Dequeue an element from the circular_queue, return a lock_list if + * the queue is not empty, or NULL if otherwise. + */ +static inline struct lock_list * __cq_dequeue(struct circular_queue *cq) { + struct lock_list * lock; + if (__cq_empty(cq)) - return -1; + return NULL; - *elem = cq->element[cq->front]; + lock = cq->element[cq->front]; cq->front = (cq->front + 1) & CQ_MASK; - return 0; + + return lock; } static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) @@ -1322,13 +1372,32 @@ static inline int get_lock_depth(struct lock_list *child) return depth; } +/* + * Return the forward or backward dependency list. + * + * @lock: the lock_list to get its class's dependency list + * @offset: the offset to struct lock_class to determine whether it is + * locks_after or locks_before + */ +static inline struct list_head *get_dep_list(struct lock_list *lock, int offset) +{ + void *lock_class = lock->class; + + return lock_class + offset; +} + +/* + * Forward- or backward-dependency search, used for both circular dependency + * checking and hardirq-unsafe/softirq-unsafe checking. + */ static int __bfs(struct lock_list *source_entry, void *data, int (*match)(struct lock_list *entry, void *data), struct lock_list **target_entry, - int forward) + int offset) { struct lock_list *entry; + struct lock_list *lock; struct list_head *head; struct circular_queue *cq = &lock_cq; int ret = 1; @@ -1339,31 +1408,21 @@ static int __bfs(struct lock_list *source_entry, goto exit; } - if (forward) - head = &source_entry->class->locks_after; - else - head = &source_entry->class->locks_before; - + head = get_dep_list(source_entry, offset); if (list_empty(head)) goto exit; __cq_init(cq); - __cq_enqueue(cq, (unsigned long)source_entry); + __cq_enqueue(cq, source_entry); - while (!__cq_empty(cq)) { - struct lock_list *lock; - - __cq_dequeue(cq, (unsigned long *)&lock); + while ((lock = __cq_dequeue(cq))) { if (!lock->class) { ret = -2; goto exit; } - if (forward) - head = &lock->class->locks_after; - else - head = &lock->class->locks_before; + head = get_dep_list(lock, offset); DEBUG_LOCKS_WARN_ON(!irqs_disabled()); @@ -1377,7 +1436,7 @@ static int __bfs(struct lock_list *source_entry, goto exit; } - if (__cq_enqueue(cq, (unsigned long)entry)) { + if (__cq_enqueue(cq, entry)) { ret = -1; goto exit; } @@ -1396,7 +1455,8 @@ static inline int __bfs_forwards(struct lock_list *src_entry, int (*match)(struct lock_list *entry, void *data), struct lock_list **target_entry) { - return __bfs(src_entry, data, match, target_entry, 1); + return __bfs(src_entry, data, match, target_entry, + offsetof(struct lock_class, locks_after)); } @@ -1405,16 +1465,11 @@ static inline int __bfs_backwards(struct lock_list *src_entry, int (*match)(struct lock_list *entry, void *data), struct lock_list **target_entry) { - return __bfs(src_entry, data, match, target_entry, 0); + return __bfs(src_entry, data, match, target_entry, + offsetof(struct lock_class, locks_before)); } -/* - * Recursive, forwards-direction lock-dependency checking, used for - * both noncyclic checking and for hardirq-unsafe/softirq-unsafe - * checking. - */ - static void print_lock_trace(struct lock_trace *trace, unsigned int spaces) { unsigned long *entries = stack_trace + trace->offset; @@ -1426,16 +1481,15 @@ static void print_lock_trace(struct lock_trace *trace, unsigned int spaces) * Print a dependency chain entry (this is only done when a deadlock * has been detected): */ -static noinline int +static noinline void print_circular_bug_entry(struct lock_list *target, int depth) { if (debug_locks_silent) - return 0; + return; printk("\n-> #%u", depth); print_lock_name(target->class); printk(KERN_CONT ":\n"); print_lock_trace(&target->trace, 6); - return 0; } static void @@ -1492,7 +1546,7 @@ print_circular_lock_scenario(struct held_lock *src, * When a circular dependency is detected, print the * header first: */ -static noinline int +static noinline void print_circular_bug_header(struct lock_list *entry, unsigned int depth, struct held_lock *check_src, struct held_lock *check_tgt) @@ -1500,7 +1554,7 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth, struct task_struct *curr = current; if (debug_locks_silent) - return 0; + return; pr_warn("\n"); pr_warn("======================================================\n"); @@ -1518,8 +1572,6 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth, pr_warn("\nthe existing dependency chain (in reverse order) is:\n"); print_circular_bug_entry(entry, depth); - - return 0; } static inline int class_equal(struct lock_list *entry, void *data) @@ -1527,10 +1579,10 @@ static inline int class_equal(struct lock_list *entry, void *data) return entry->class == data; } -static noinline int print_circular_bug(struct lock_list *this, - struct lock_list *target, - struct held_lock *check_src, - struct held_lock *check_tgt) +static noinline void print_circular_bug(struct lock_list *this, + struct lock_list *target, + struct held_lock *check_src, + struct held_lock *check_tgt) { struct task_struct *curr = current; struct lock_list *parent; @@ -1538,10 +1590,10 @@ static noinline int print_circular_bug(struct lock_list *this, int depth; if (!debug_locks_off_graph_unlock() || debug_locks_silent) - return 0; + return; if (!save_trace(&this->trace)) - return 0; + return; depth = get_lock_depth(target); @@ -1563,21 +1615,17 @@ static noinline int print_circular_bug(struct lock_list *this, printk("\nstack backtrace:\n"); dump_stack(); - - return 0; } -static noinline int print_bfs_bug(int ret) +static noinline void print_bfs_bug(int ret) { if (!debug_locks_off_graph_unlock()) - return 0; + return; /* * Breadth-first-search failed, graph got corrupted? */ WARN(1, "lockdep bfs error:%d\n", ret); - - return 0; } static int noop_count(struct lock_list *entry, void *data) @@ -1640,36 +1688,95 @@ unsigned long lockdep_count_backward_deps(struct lock_class *class) } /* - * Prove that the dependency graph starting at <entry> can not - * lead to <target>. Print an error and return 0 if it does. + * Check that the dependency graph starting at <src> can lead to + * <target> or not. Print an error and return 0 if it does. */ static noinline int -check_noncircular(struct lock_list *root, struct lock_class *target, - struct lock_list **target_entry) +check_path(struct lock_class *target, struct lock_list *src_entry, + struct lock_list **target_entry) { - int result; + int ret; + + ret = __bfs_forwards(src_entry, (void *)target, class_equal, + target_entry); + + if (unlikely(ret < 0)) + print_bfs_bug(ret); + + return ret; +} + +/* + * Prove that the dependency graph starting at <src> can not + * lead to <target>. If it can, there is a circle when adding + * <target> -> <src> dependency. + * + * Print an error and return 0 if it does. + */ +static noinline int +check_noncircular(struct held_lock *src, struct held_lock *target, + struct lock_trace *trace) +{ + int ret; + struct lock_list *uninitialized_var(target_entry); + struct lock_list src_entry = { + .class = hlock_class(src), + .parent = NULL, + }; debug_atomic_inc(nr_cyclic_checks); - result = __bfs_forwards(root, target, class_equal, target_entry); + ret = check_path(hlock_class(target), &src_entry, &target_entry); - return result; + if (unlikely(!ret)) { + if (!trace->nr_entries) { + /* + * If save_trace fails here, the printing might + * trigger a WARN but because of the !nr_entries it + * should not do bad things. + */ + save_trace(trace); + } + + print_circular_bug(&src_entry, target_entry, src, target); + } + + return ret; } +#ifdef CONFIG_LOCKDEP_SMALL +/* + * Check that the dependency graph starting at <src> can lead to + * <target> or not. If it can, <src> -> <target> dependency is already + * in the graph. + * + * Print an error and return 2 if it does or 1 if it does not. + */ static noinline int -check_redundant(struct lock_list *root, struct lock_class *target, - struct lock_list **target_entry) +check_redundant(struct held_lock *src, struct held_lock *target) { - int result; + int ret; + struct lock_list *uninitialized_var(target_entry); + struct lock_list src_entry = { + .class = hlock_class(src), + .parent = NULL, + }; debug_atomic_inc(nr_redundant_checks); - result = __bfs_forwards(root, target, class_equal, target_entry); + ret = check_path(hlock_class(target), &src_entry, &target_entry); - return result; + if (!ret) { + debug_atomic_inc(nr_redundant); + ret = 2; + } else if (ret < 0) + ret = 0; + + return ret; } +#endif -#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) +#ifdef CONFIG_TRACE_IRQFLAGS static inline int usage_accumulate(struct lock_list *entry, void *mask) { @@ -1766,7 +1873,7 @@ static void print_lock_class_header(struct lock_class *class, int depth) */ static void __used print_shortest_lock_dependencies(struct lock_list *leaf, - struct lock_list *root) + struct lock_list *root) { struct lock_list *entry = leaf; int depth; @@ -1788,8 +1895,6 @@ print_shortest_lock_dependencies(struct lock_list *leaf, entry = get_lock_parent(entry); depth--; } while (entry && (depth >= 0)); - - return; } static void @@ -1848,7 +1953,7 @@ print_irq_lock_scenario(struct lock_list *safe_entry, printk("\n *** DEADLOCK ***\n\n"); } -static int +static void print_bad_irq_dependency(struct task_struct *curr, struct lock_list *prev_root, struct lock_list *next_root, @@ -1861,7 +1966,7 @@ print_bad_irq_dependency(struct task_struct *curr, const char *irqclass) { if (!debug_locks_off_graph_unlock() || debug_locks_silent) - return 0; + return; pr_warn("\n"); pr_warn("=====================================================\n"); @@ -1907,19 +2012,17 @@ print_bad_irq_dependency(struct task_struct *curr, pr_warn("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass); if (!save_trace(&prev_root->trace)) - return 0; + return; print_shortest_lock_dependencies(backwards_entry, prev_root); pr_warn("\nthe dependencies between the lock to be acquired"); pr_warn(" and %s-irq-unsafe lock:\n", irqclass); if (!save_trace(&next_root->trace)) - return 0; + return; print_shortest_lock_dependencies(forwards_entry, next_root); pr_warn("\nstack backtrace:\n"); dump_stack(); - - return 0; } static const char *state_names[] = { @@ -2066,8 +2169,10 @@ static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, this.class = hlock_class(prev); ret = __bfs_backwards(&this, &usage_mask, usage_accumulate, NULL); - if (ret < 0) - return print_bfs_bug(ret); + if (ret < 0) { + print_bfs_bug(ret); + return 0; + } usage_mask &= LOCKF_USED_IN_IRQ_ALL; if (!usage_mask) @@ -2083,8 +2188,10 @@ static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, that.class = hlock_class(next); ret = find_usage_forwards(&that, forward_mask, &target_entry1); - if (ret < 0) - return print_bfs_bug(ret); + if (ret < 0) { + print_bfs_bug(ret); + return 0; + } if (ret == 1) return ret; @@ -2096,8 +2203,10 @@ static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, backward_mask = original_mask(target_entry1->class->usage_mask); ret = find_usage_backwards(&this, backward_mask, &target_entry); - if (ret < 0) - return print_bfs_bug(ret); + if (ret < 0) { + print_bfs_bug(ret); + return 0; + } if (DEBUG_LOCKS_WARN_ON(ret == 1)) return 1; @@ -2111,11 +2220,13 @@ static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, if (DEBUG_LOCKS_WARN_ON(ret == -1)) return 1; - return print_bad_irq_dependency(curr, &this, &that, - target_entry, target_entry1, - prev, next, - backward_bit, forward_bit, - state_name(backward_bit)); + print_bad_irq_dependency(curr, &this, &that, + target_entry, target_entry1, + prev, next, + backward_bit, forward_bit, + state_name(backward_bit)); + + return 0; } static void inc_chains(void) @@ -2143,11 +2254,10 @@ static inline void inc_chains(void) nr_process_chains++; } -#endif +#endif /* CONFIG_TRACE_IRQFLAGS */ static void -print_deadlock_scenario(struct held_lock *nxt, - struct held_lock *prv) +print_deadlock_scenario(struct held_lock *nxt, struct held_lock *prv) { struct lock_class *next = hlock_class(nxt); struct lock_class *prev = hlock_class(prv); @@ -2165,12 +2275,12 @@ print_deadlock_scenario(struct held_lock *nxt, printk(" May be due to missing lock nesting notation\n\n"); } -static int +static void print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, struct held_lock *next) { if (!debug_locks_off_graph_unlock() || debug_locks_silent) - return 0; + return; pr_warn("\n"); pr_warn("============================================\n"); @@ -2189,8 +2299,6 @@ print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, pr_warn("\nstack backtrace:\n"); dump_stack(); - - return 0; } /* @@ -2202,8 +2310,7 @@ print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read */ static int -check_deadlock(struct task_struct *curr, struct held_lock *next, - struct lockdep_map *next_instance, int read) +check_deadlock(struct task_struct *curr, struct held_lock *next) { struct held_lock *prev; struct held_lock *nest = NULL; @@ -2222,7 +2329,7 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, * Allow read-after-read recursion of the same * lock class (i.e. read_lock(lock)+read_lock(lock)): */ - if ((read == 2) && prev->read) + if ((next->read == 2) && prev->read) return 2; /* @@ -2232,14 +2339,15 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, if (nest) return 2; - return print_deadlock_bug(curr, prev, next); + print_deadlock_bug(curr, prev, next); + return 0; } return 1; } /* * There was a chain-cache miss, and we are about to add a new dependency - * to a previous lock. We recursively validate the following rules: + * to a previous lock. We validate the following rules: * * - would the adding of the <prev> -> <next> dependency create a * circular dependency in the graph? [== circular deadlock] @@ -2263,9 +2371,7 @@ static int check_prev_add(struct task_struct *curr, struct held_lock *prev, struct held_lock *next, int distance, struct lock_trace *trace) { - struct lock_list *uninitialized_var(target_entry); struct lock_list *entry; - struct lock_list this; int ret; if (!hlock_class(prev)->key || !hlock_class(next)->key) { @@ -2289,28 +2395,16 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, /* * Prove that the new <prev> -> <next> dependency would not * create a circular dependency in the graph. (We do this by - * forward-recursing into the graph starting at <next>, and - * checking whether we can reach <prev>.) + * a breadth-first search into the graph starting at <next>, + * and check whether we can reach <prev>.) * - * We are using global variables to control the recursion, to - * keep the stackframe size of the recursive functions low: + * The search is limited by the size of the circular queue (i.e., + * MAX_CIRCULAR_QUEUE_SIZE) which keeps track of a breadth of nodes + * in the graph whose neighbours are to be checked. */ - this.class = hlock_class(next); - this.parent = NULL; - ret = check_noncircular(&this, hlock_class(prev), &target_entry); - if (unlikely(!ret)) { - if (!trace->nr_entries) { - /* - * If save_trace fails here, the printing might - * trigger a WARN but because of the !nr_entries it - * should not do bad things. - */ - save_trace(trace); - } - return print_circular_bug(&this, target_entry, next, prev); - } - else if (unlikely(ret < 0)) - return print_bfs_bug(ret); + ret = check_noncircular(next, prev, trace); + if (unlikely(ret <= 0)) + return 0; if (!check_irq_usage(curr, prev, next)) return 0; @@ -2341,19 +2435,14 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, } } +#ifdef CONFIG_LOCKDEP_SMALL /* * Is the <prev> -> <next> link redundant? */ - this.class = hlock_class(prev); - this.parent = NULL; - ret = check_redundant(&this, hlock_class(next), &target_entry); - if (!ret) { - debug_atomic_inc(nr_redundant); - return 2; - } - if (ret < 0) - return print_bfs_bug(ret); - + ret = check_redundant(prev, next); + if (ret != 1) + return ret; +#endif if (!trace->nr_entries && !save_trace(trace)) return 0; @@ -2505,12 +2594,13 @@ static void print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next) { struct held_lock *hlock; - u64 chain_key = 0; + u64 chain_key = INITIAL_CHAIN_KEY; int depth = curr->lockdep_depth; - int i; + int i = get_first_held_lock(curr, hlock_next); - printk("depth: %u\n", depth + 1); - for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) { + printk("depth: %u (irq_context %u)\n", depth - i + 1, + hlock_next->irq_context); + for (; i < depth; i++) { hlock = curr->held_locks + i; chain_key = print_chain_key_iteration(hlock->class_idx, chain_key); @@ -2524,13 +2614,13 @@ print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_ne static void print_chain_keys_chain(struct lock_chain *chain) { int i; - u64 chain_key = 0; + u64 chain_key = INITIAL_CHAIN_KEY; int class_id; printk("depth: %u\n", chain->depth); for (i = 0; i < chain->depth; i++) { class_id = chain_hlocks[chain->base + i]; - chain_key = print_chain_key_iteration(class_id + 1, chain_key); + chain_key = print_chain_key_iteration(class_id, chain_key); print_lock_name(lock_classes + class_id); printk("\n"); @@ -2581,7 +2671,7 @@ static int check_no_collision(struct task_struct *curr, } for (j = 0; j < chain->depth - 1; j++, i++) { - id = curr->held_locks[i].class_idx - 1; + id = curr->held_locks[i].class_idx; if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) { print_collision(curr, hlock, chain); @@ -2664,7 +2754,7 @@ static inline int add_chain_cache(struct task_struct *curr, if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { chain->base = nr_chain_hlocks; for (j = 0; j < chain->depth - 1; j++, i++) { - int lock_id = curr->held_locks[i].class_idx - 1; + int lock_id = curr->held_locks[i].class_idx; chain_hlocks[chain->base + j] = lock_id; } chain_hlocks[chain->base + j] = class - lock_classes; @@ -2754,8 +2844,9 @@ cache_hit: return 1; } -static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, - struct held_lock *hlock, int chain_head, u64 chain_key) +static int validate_chain(struct task_struct *curr, + struct held_lock *hlock, + int chain_head, u64 chain_key) { /* * Trylock needs to maintain the stack of held locks, but it @@ -2776,12 +2867,18 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, * - is softirq-safe, if this lock is hardirq-unsafe * * And check whether the new lock's dependency graph - * could lead back to the previous lock. + * could lead back to the previous lock: * - * any of these scenarios could lead to a deadlock. If - * All validations + * - within the current held-lock stack + * - across our accumulated lock dependency records + * + * any of these scenarios could lead to a deadlock. */ - int ret = check_deadlock(curr, hlock, lock, hlock->read); + /* + * The simple case: does the current hold the same lock + * already? + */ + int ret = check_deadlock(curr, hlock); if (!ret) return 0; @@ -2812,16 +2909,12 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, } #else static inline int validate_chain(struct task_struct *curr, - struct lockdep_map *lock, struct held_lock *hlock, - int chain_head, u64 chain_key) + struct held_lock *hlock, + int chain_head, u64 chain_key) { return 1; } - -static void print_lock_trace(struct lock_trace *trace, unsigned int spaces) -{ -} -#endif +#endif /* CONFIG_PROVE_LOCKING */ /* * We are building curr_chain_key incrementally, so double-check @@ -2832,7 +2925,7 @@ static void check_chain_key(struct task_struct *curr) #ifdef CONFIG_DEBUG_LOCKDEP struct held_lock *hlock, *prev_hlock = NULL; unsigned int i; - u64 chain_key = 0; + u64 chain_key = INITIAL_CHAIN_KEY; for (i = 0; i < curr->lockdep_depth; i++) { hlock = curr->held_locks + i; @@ -2848,15 +2941,17 @@ static void check_chain_key(struct task_struct *curr) (unsigned long long)hlock->prev_chain_key); return; } + /* - * Whoops ran out of static storage again? + * hlock->class_idx can't go beyond MAX_LOCKDEP_KEYS, but is + * it registered lock class index? */ - if (DEBUG_LOCKS_WARN_ON(hlock->class_idx > MAX_LOCKDEP_KEYS)) + if (DEBUG_LOCKS_WARN_ON(!test_bit(hlock->class_idx, lock_classes_in_use))) return; if (prev_hlock && (prev_hlock->irq_context != hlock->irq_context)) - chain_key = 0; + chain_key = INITIAL_CHAIN_KEY; chain_key = iterate_chain_key(chain_key, hlock->class_idx); prev_hlock = hlock; } @@ -2874,14 +2969,11 @@ static void check_chain_key(struct task_struct *curr) #endif } +#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) static int mark_lock(struct task_struct *curr, struct held_lock *this, enum lock_usage_bit new_bit); -#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) - - -static void -print_usage_bug_scenario(struct held_lock *lock) +static void print_usage_bug_scenario(struct held_lock *lock) { struct lock_class *class = hlock_class(lock); @@ -2898,12 +2990,12 @@ print_usage_bug_scenario(struct held_lock *lock) printk("\n *** DEADLOCK ***\n\n"); } -static int +static void print_usage_bug(struct task_struct *curr, struct held_lock *this, enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) { if (!debug_locks_off_graph_unlock() || debug_locks_silent) - return 0; + return; pr_warn("\n"); pr_warn("================================\n"); @@ -2933,8 +3025,6 @@ print_usage_bug(struct task_struct *curr, struct held_lock *this, pr_warn("\nstack backtrace:\n"); dump_stack(); - - return 0; } /* @@ -2944,8 +3034,10 @@ static inline int valid_state(struct task_struct *curr, struct held_lock *this, enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) { - if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) - return print_usage_bug(curr, this, bad_bit, new_bit); + if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) { + print_usage_bug(curr, this, bad_bit, new_bit); + return 0; + } return 1; } @@ -2953,7 +3045,7 @@ valid_state(struct task_struct *curr, struct held_lock *this, /* * print irq inversion bug: */ -static int +static void print_irq_inversion_bug(struct task_struct *curr, struct lock_list *root, struct lock_list *other, struct held_lock *this, int forwards, @@ -2964,7 +3056,7 @@ print_irq_inversion_bug(struct task_struct *curr, int depth; if (!debug_locks_off_graph_unlock() || debug_locks_silent) - return 0; + return; pr_warn("\n"); pr_warn("========================================================\n"); @@ -3005,13 +3097,11 @@ print_irq_inversion_bug(struct task_struct *curr, pr_warn("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); if (!save_trace(&root->trace)) - return 0; + return; print_shortest_lock_dependencies(other, root); pr_warn("\nstack backtrace:\n"); dump_stack(); - - return 0; } /* @@ -3029,13 +3119,16 @@ check_usage_forwards(struct task_struct *curr, struct held_lock *this, root.parent = NULL; root.class = hlock_class(this); ret = find_usage_forwards(&root, lock_flag(bit), &target_entry); - if (ret < 0) - return print_bfs_bug(ret); + if (ret < 0) { + print_bfs_bug(ret); + return 0; + } if (ret == 1) return ret; - return print_irq_inversion_bug(curr, &root, target_entry, - this, 1, irqclass); + print_irq_inversion_bug(curr, &root, target_entry, + this, 1, irqclass); + return 0; } /* @@ -3053,13 +3146,16 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this, root.parent = NULL; root.class = hlock_class(this); ret = find_usage_backwards(&root, lock_flag(bit), &target_entry); - if (ret < 0) - return print_bfs_bug(ret); + if (ret < 0) { + print_bfs_bug(ret); + return 0; + } if (ret == 1) return ret; - return print_irq_inversion_bug(curr, &root, target_entry, - this, 0, irqclass); + print_irq_inversion_bug(curr, &root, target_entry, + this, 0, irqclass); + return 0; } void print_irqtrace_events(struct task_struct *curr) @@ -3142,7 +3238,7 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this, * Validate that the lock dependencies don't have conflicting usage * states. */ - if ((!read || !dir || STRICT_READ_CHECKS) && + if ((!read || STRICT_READ_CHECKS) && !usage(curr, this, excl_bit, state_name(new_bit & ~LOCK_USAGE_READ_MASK))) return 0; @@ -3367,8 +3463,12 @@ void trace_softirqs_off(unsigned long ip) debug_atomic_inc(redundant_softirqs_off); } -static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) +static int +mark_usage(struct task_struct *curr, struct held_lock *hlock, int check) { + if (!check) + goto lock_used; + /* * If non-trylock use in a hardirq or softirq context, then * mark the lock as used in these contexts: @@ -3412,6 +3512,11 @@ static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) } } +lock_used: + /* mark it as used: */ + if (!mark_lock(curr, hlock, LOCK_USED)) + return 0; + return 1; } @@ -3443,35 +3548,6 @@ static int separate_irq_context(struct task_struct *curr, return 0; } -#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ - -static inline -int mark_lock_irq(struct task_struct *curr, struct held_lock *this, - enum lock_usage_bit new_bit) -{ - WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */ - return 1; -} - -static inline int mark_irqflags(struct task_struct *curr, - struct held_lock *hlock) -{ - return 1; -} - -static inline unsigned int task_irq_context(struct task_struct *task) -{ - return 0; -} - -static inline int separate_irq_context(struct task_struct *curr, - struct held_lock *hlock) -{ - return 0; -} - -#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ - /* * Mark a lock with a usage bit, and validate the state transition: */ @@ -3480,6 +3556,11 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, { unsigned int new_mask = 1 << new_bit, ret = 1; + if (new_bit >= LOCK_USAGE_STATES) { + DEBUG_LOCKS_WARN_ON(1); + return 0; + } + /* * If already set then do not dirty the cacheline, * nor do any checks: @@ -3503,25 +3584,13 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, return 0; switch (new_bit) { -#define LOCKDEP_STATE(__STATE) \ - case LOCK_USED_IN_##__STATE: \ - case LOCK_USED_IN_##__STATE##_READ: \ - case LOCK_ENABLED_##__STATE: \ - case LOCK_ENABLED_##__STATE##_READ: -#include "lockdep_states.h" -#undef LOCKDEP_STATE - ret = mark_lock_irq(curr, this, new_bit); - if (!ret) - return 0; - break; case LOCK_USED: debug_atomic_dec(nr_unused_locks); break; default: - if (!debug_locks_off_graph_unlock()) + ret = mark_lock_irq(curr, this, new_bit); + if (!ret) return 0; - WARN_ON(1); - return 0; } graph_unlock(); @@ -3539,6 +3608,27 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, return ret; } +#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ + +static inline int +mark_usage(struct task_struct *curr, struct held_lock *hlock, int check) +{ + return 1; +} + +static inline unsigned int task_irq_context(struct task_struct *task) +{ + return 0; +} + +static inline int separate_irq_context(struct task_struct *curr, + struct held_lock *hlock) +{ + return 0; +} + +#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ + /* * Initialize a lock instance's lock-class mapping info: */ @@ -3602,15 +3692,15 @@ EXPORT_SYMBOL_GPL(lockdep_init_map); struct lock_class_key __lockdep_no_validate__; EXPORT_SYMBOL_GPL(__lockdep_no_validate__); -static int +static void print_lock_nested_lock_not_held(struct task_struct *curr, struct held_lock *hlock, unsigned long ip) { if (!debug_locks_off()) - return 0; + return; if (debug_locks_silent) - return 0; + return; pr_warn("\n"); pr_warn("==================================\n"); @@ -3632,8 +3722,6 @@ print_lock_nested_lock_not_held(struct task_struct *curr, pr_warn("\nstack backtrace:\n"); dump_stack(); - - return 0; } static int __lock_is_held(const struct lockdep_map *lock, int read); @@ -3698,24 +3786,24 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) return 0; - class_idx = class - lock_classes + 1; + class_idx = class - lock_classes; if (depth) { hlock = curr->held_locks + depth - 1; if (hlock->class_idx == class_idx && nest_lock) { - if (hlock->references) { - /* - * Check: unsigned int references:12, overflow. - */ - if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1)) - return 0; + if (!references) + references++; + if (!hlock->references) hlock->references++; - } else { - hlock->references = 2; - } - return 1; + hlock->references += references; + + /* Overflow */ + if (DEBUG_LOCKS_WARN_ON(hlock->references < references)) + return 0; + + return 2; } } @@ -3742,11 +3830,8 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, #endif hlock->pin_count = pin_count; - if (check && !mark_irqflags(curr, hlock)) - return 0; - - /* mark it as used: */ - if (!mark_lock(curr, hlock, LOCK_USED)) + /* Initialize the lock usage bit */ + if (!mark_usage(curr, hlock, check)) return 0; /* @@ -3760,9 +3845,9 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, * the hash, not class->key. */ /* - * Whoops, we did it again.. ran straight out of our static allocation. + * Whoops, we did it again.. class_idx is invalid. */ - if (DEBUG_LOCKS_WARN_ON(class_idx > MAX_LOCKDEP_KEYS)) + if (DEBUG_LOCKS_WARN_ON(!test_bit(class_idx, lock_classes_in_use))) return 0; chain_key = curr->curr_chain_key; @@ -3770,27 +3855,29 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, /* * How can we have a chain hash when we ain't got no keys?! */ - if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) + if (DEBUG_LOCKS_WARN_ON(chain_key != INITIAL_CHAIN_KEY)) return 0; chain_head = 1; } hlock->prev_chain_key = chain_key; if (separate_irq_context(curr, hlock)) { - chain_key = 0; + chain_key = INITIAL_CHAIN_KEY; chain_head = 1; } chain_key = iterate_chain_key(chain_key, class_idx); - if (nest_lock && !__lock_is_held(nest_lock, -1)) - return print_lock_nested_lock_not_held(curr, hlock, ip); + if (nest_lock && !__lock_is_held(nest_lock, -1)) { + print_lock_nested_lock_not_held(curr, hlock, ip); + return 0; + } if (!debug_locks_silent) { WARN_ON_ONCE(depth && !hlock_class(hlock - 1)->key); WARN_ON_ONCE(!hlock_class(hlock)->key); } - if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) + if (!validate_chain(curr, hlock, chain_head, chain_key)) return 0; curr->curr_chain_key = chain_key; @@ -3819,14 +3906,14 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, return 1; } -static int -print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, - unsigned long ip) +static void print_unlock_imbalance_bug(struct task_struct *curr, + struct lockdep_map *lock, + unsigned long ip) { if (!debug_locks_off()) - return 0; + return; if (debug_locks_silent) - return 0; + return; pr_warn("\n"); pr_warn("=====================================\n"); @@ -3844,8 +3931,6 @@ print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, pr_warn("\nstack backtrace:\n"); dump_stack(); - - return 0; } static int match_held_lock(const struct held_lock *hlock, @@ -3877,7 +3962,7 @@ static int match_held_lock(const struct held_lock *hlock, if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) return 0; - if (hlock->class_idx == class - lock_classes + 1) + if (hlock->class_idx == class - lock_classes) return 1; } @@ -3921,22 +4006,33 @@ out: } static int reacquire_held_locks(struct task_struct *curr, unsigned int depth, - int idx) + int idx, unsigned int *merged) { struct held_lock *hlock; + int first_idx = idx; if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) return 0; for (hlock = curr->held_locks + idx; idx < depth; idx++, hlock++) { - if (!__lock_acquire(hlock->instance, + switch (__lock_acquire(hlock->instance, hlock_class(hlock)->subclass, hlock->trylock, hlock->read, hlock->check, hlock->hardirqs_off, hlock->nest_lock, hlock->acquire_ip, - hlock->references, hlock->pin_count)) + hlock->references, hlock->pin_count)) { + case 0: return 1; + case 1: + break; + case 2: + *merged += (idx == first_idx); + break; + default: + WARN_ON(1); + return 0; + } } return 0; } @@ -3947,9 +4043,9 @@ __lock_set_class(struct lockdep_map *lock, const char *name, unsigned long ip) { struct task_struct *curr = current; + unsigned int depth, merged = 0; struct held_lock *hlock; struct lock_class *class; - unsigned int depth; int i; if (unlikely(!debug_locks)) @@ -3964,24 +4060,26 @@ __lock_set_class(struct lockdep_map *lock, const char *name, return 0; hlock = find_held_lock(curr, lock, depth, &i); - if (!hlock) - return print_unlock_imbalance_bug(curr, lock, ip); + if (!hlock) { + print_unlock_imbalance_bug(curr, lock, ip); + return 0; + } lockdep_init_map(lock, name, key, 0); class = register_lock_class(lock, subclass, 0); - hlock->class_idx = class - lock_classes + 1; + hlock->class_idx = class - lock_classes; curr->lockdep_depth = i; curr->curr_chain_key = hlock->prev_chain_key; - if (reacquire_held_locks(curr, depth, i)) + if (reacquire_held_locks(curr, depth, i, &merged)) return 0; /* * I took it apart and put it back together again, except now I have * these 'spare' parts.. where shall I put them. */ - if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) + if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - merged)) return 0; return 1; } @@ -3989,8 +4087,8 @@ __lock_set_class(struct lockdep_map *lock, const char *name, static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) { struct task_struct *curr = current; + unsigned int depth, merged = 0; struct held_lock *hlock; - unsigned int depth; int i; if (unlikely(!debug_locks)) @@ -4005,8 +4103,10 @@ static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) return 0; hlock = find_held_lock(curr, lock, depth, &i); - if (!hlock) - return print_unlock_imbalance_bug(curr, lock, ip); + if (!hlock) { + print_unlock_imbalance_bug(curr, lock, ip); + return 0; + } curr->lockdep_depth = i; curr->curr_chain_key = hlock->prev_chain_key; @@ -4015,7 +4115,11 @@ static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) hlock->read = 1; hlock->acquire_ip = ip; - if (reacquire_held_locks(curr, depth, i)) + if (reacquire_held_locks(curr, depth, i, &merged)) + return 0; + + /* Merging can't happen with unchanged classes.. */ + if (DEBUG_LOCKS_WARN_ON(merged)) return 0; /* @@ -4024,6 +4128,7 @@ static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) */ if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) return 0; + return 1; } @@ -4035,11 +4140,11 @@ static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) * @nested is an hysterical artifact, needs a tree wide cleanup. */ static int -__lock_release(struct lockdep_map *lock, int nested, unsigned long ip) +__lock_release(struct lockdep_map *lock, unsigned long ip) { struct task_struct *curr = current; + unsigned int depth, merged = 1; struct held_lock *hlock; - unsigned int depth; int i; if (unlikely(!debug_locks)) @@ -4050,16 +4155,20 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) * So we're all set to release this lock.. wait what lock? We don't * own any locks, you've been drinking again? */ - if (DEBUG_LOCKS_WARN_ON(depth <= 0)) - return print_unlock_imbalance_bug(curr, lock, ip); + if (depth <= 0) { + print_unlock_imbalance_bug(curr, lock, ip); + return 0; + } /* * Check whether the lock exists in the current stack * of held locks: */ hlock = find_held_lock(curr, lock, depth, &i); - if (!hlock) - return print_unlock_imbalance_bug(curr, lock, ip); + if (!hlock) { + print_unlock_imbalance_bug(curr, lock, ip); + return 0; + } if (hlock->instance == lock) lock_release_holdtime(hlock); @@ -4094,14 +4203,15 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) if (i == depth-1) return 1; - if (reacquire_held_locks(curr, depth, i + 1)) + if (reacquire_held_locks(curr, depth, i + 1, &merged)) return 0; /* * We had N bottles of beer on the wall, we drank one, but now * there's not N-1 bottles of beer left on the wall... + * Pouring two of the bottles together is acceptable. */ - DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth-1); + DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - merged); /* * Since reacquire_held_locks() would have called check_chain_key() @@ -4319,7 +4429,7 @@ void lock_release(struct lockdep_map *lock, int nested, check_flags(flags); current->lockdep_recursion = 1; trace_lock_release(lock, ip); - if (__lock_release(lock, nested, ip)) + if (__lock_release(lock, ip)) check_chain_key(current); current->lockdep_recursion = 0; raw_local_irq_restore(flags); @@ -4402,14 +4512,14 @@ void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) EXPORT_SYMBOL_GPL(lock_unpin_lock); #ifdef CONFIG_LOCK_STAT -static int -print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, - unsigned long ip) +static void print_lock_contention_bug(struct task_struct *curr, + struct lockdep_map *lock, + unsigned long ip) { if (!debug_locks_off()) - return 0; + return; if (debug_locks_silent) - return 0; + return; pr_warn("\n"); pr_warn("=================================\n"); @@ -4427,8 +4537,6 @@ print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, pr_warn("\nstack backtrace:\n"); dump_stack(); - - return 0; } static void @@ -4573,9 +4681,7 @@ void lockdep_reset(void) int i; raw_local_irq_save(flags); - current->curr_chain_key = 0; - current->lockdep_depth = 0; - current->lockdep_recursion = 0; + lockdep_init_task(current); memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); nr_hardirq_chains = 0; nr_softirq_chains = 0; @@ -4615,9 +4721,9 @@ static void remove_class_from_lock_chain(struct pending_free *pf, return; recalc: - chain_key = 0; + chain_key = INITIAL_CHAIN_KEY; for (i = chain->base; i < chain->base + chain->depth; i++) - chain_key = iterate_chain_key(chain_key, chain_hlocks[i] + 1); + chain_key = iterate_chain_key(chain_key, chain_hlocks[i]); if (chain->depth && chain->chain_key == chain_key) return; /* Overwrite the chain key for concurrent RCU readers. */ @@ -4691,6 +4797,7 @@ static void zap_class(struct pending_free *pf, struct lock_class *class) WRITE_ONCE(class->key, NULL); WRITE_ONCE(class->name, NULL); nr_lock_classes--; + __clear_bit(class - lock_classes, lock_classes_in_use); } else { WARN_ONCE(true, "%s() failed for class %s\n", __func__, class->name); @@ -5036,6 +5143,7 @@ void __init lockdep_init(void) printk(" memory used by lock dependency info: %zu kB\n", (sizeof(lock_classes) + + sizeof(lock_classes_in_use) + sizeof(classhash_table) + sizeof(list_entries) + sizeof(list_entries_in_use) + diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h index 150ec3f0c5b5..cc83568d5012 100644 --- a/kernel/locking/lockdep_internals.h +++ b/kernel/locking/lockdep_internals.h @@ -131,7 +131,6 @@ extern unsigned int nr_hardirq_chains; extern unsigned int nr_softirq_chains; extern unsigned int nr_process_chains; extern unsigned int max_lockdep_depth; -extern unsigned int max_recursion_depth; extern unsigned int max_bfs_queue_depth; @@ -160,25 +159,22 @@ lockdep_count_backward_deps(struct lock_class *class) * and we want to avoid too much cache bouncing. */ struct lockdep_stats { - int chain_lookup_hits; - int chain_lookup_misses; - int hardirqs_on_events; - int hardirqs_off_events; - int redundant_hardirqs_on; - int redundant_hardirqs_off; - int softirqs_on_events; - int softirqs_off_events; - int redundant_softirqs_on; - int redundant_softirqs_off; - int nr_unused_locks; - int nr_redundant_checks; - int nr_redundant; - int nr_cyclic_checks; - int nr_cyclic_check_recursions; - int nr_find_usage_forwards_checks; - int nr_find_usage_forwards_recursions; - int nr_find_usage_backwards_checks; - int nr_find_usage_backwards_recursions; + unsigned long chain_lookup_hits; + unsigned int chain_lookup_misses; + unsigned long hardirqs_on_events; + unsigned long hardirqs_off_events; + unsigned long redundant_hardirqs_on; + unsigned long redundant_hardirqs_off; + unsigned long softirqs_on_events; + unsigned long softirqs_off_events; + unsigned long redundant_softirqs_on; + unsigned long redundant_softirqs_off; + int nr_unused_locks; + unsigned int nr_redundant_checks; + unsigned int nr_redundant; + unsigned int nr_cyclic_checks; + unsigned int nr_find_usage_forwards_checks; + unsigned int nr_find_usage_backwards_checks; /* * Per lock class locking operation stat counts diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c deleted file mode 100644 index 0b1f77957240..000000000000 --- a/kernel/locking/rwsem-xadd.c +++ /dev/null @@ -1,745 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* rwsem.c: R/W semaphores: contention handling functions - * - * Written by David Howells (dhowells@redhat.com). - * Derived from arch/i386/kernel/semaphore.c - * - * Writer lock-stealing by Alex Shi <alex.shi@intel.com> - * and Michel Lespinasse <walken@google.com> - * - * Optimistic spinning by Tim Chen <tim.c.chen@intel.com> - * and Davidlohr Bueso <davidlohr@hp.com>. Based on mutexes. - */ -#include <linux/rwsem.h> -#include <linux/init.h> -#include <linux/export.h> -#include <linux/sched/signal.h> -#include <linux/sched/rt.h> -#include <linux/sched/wake_q.h> -#include <linux/sched/debug.h> -#include <linux/osq_lock.h> - -#include "rwsem.h" - -/* - * Guide to the rw_semaphore's count field for common values. - * (32-bit case illustrated, similar for 64-bit) - * - * 0x0000000X (1) X readers active or attempting lock, no writer waiting - * X = #active_readers + #readers attempting to lock - * (X*ACTIVE_BIAS) - * - * 0x00000000 rwsem is unlocked, and no one is waiting for the lock or - * attempting to read lock or write lock. - * - * 0xffff000X (1) X readers active or attempting lock, with waiters for lock - * X = #active readers + # readers attempting lock - * (X*ACTIVE_BIAS + WAITING_BIAS) - * (2) 1 writer attempting lock, no waiters for lock - * X-1 = #active readers + #readers attempting lock - * ((X-1)*ACTIVE_BIAS + ACTIVE_WRITE_BIAS) - * (3) 1 writer active, no waiters for lock - * X-1 = #active readers + #readers attempting lock - * ((X-1)*ACTIVE_BIAS + ACTIVE_WRITE_BIAS) - * - * 0xffff0001 (1) 1 reader active or attempting lock, waiters for lock - * (WAITING_BIAS + ACTIVE_BIAS) - * (2) 1 writer active or attempting lock, no waiters for lock - * (ACTIVE_WRITE_BIAS) - * - * 0xffff0000 (1) There are writers or readers queued but none active - * or in the process of attempting lock. - * (WAITING_BIAS) - * Note: writer can attempt to steal lock for this count by adding - * ACTIVE_WRITE_BIAS in cmpxchg and checking the old count - * - * 0xfffe0001 (1) 1 writer active, or attempting lock. Waiters on queue. - * (ACTIVE_WRITE_BIAS + WAITING_BIAS) - * - * Note: Readers attempt to lock by adding ACTIVE_BIAS in down_read and checking - * the count becomes more than 0 for successful lock acquisition, - * i.e. the case where there are only readers or nobody has lock. - * (1st and 2nd case above). - * - * Writers attempt to lock by adding ACTIVE_WRITE_BIAS in down_write and - * checking the count becomes ACTIVE_WRITE_BIAS for successful lock - * acquisition (i.e. nobody else has lock or attempts lock). If - * unsuccessful, in rwsem_down_write_failed, we'll check to see if there - * are only waiters but none active (5th case above), and attempt to - * steal the lock. - * - */ - -/* - * Initialize an rwsem: - */ -void __init_rwsem(struct rw_semaphore *sem, const char *name, - struct lock_class_key *key) -{ -#ifdef CONFIG_DEBUG_LOCK_ALLOC - /* - * Make sure we are not reinitializing a held semaphore: - */ - debug_check_no_locks_freed((void *)sem, sizeof(*sem)); - lockdep_init_map(&sem->dep_map, name, key, 0); -#endif - atomic_long_set(&sem->count, RWSEM_UNLOCKED_VALUE); - raw_spin_lock_init(&sem->wait_lock); - INIT_LIST_HEAD(&sem->wait_list); -#ifdef CONFIG_RWSEM_SPIN_ON_OWNER - sem->owner = NULL; - osq_lock_init(&sem->osq); -#endif -} - -EXPORT_SYMBOL(__init_rwsem); - -enum rwsem_waiter_type { - RWSEM_WAITING_FOR_WRITE, - RWSEM_WAITING_FOR_READ -}; - -struct rwsem_waiter { - struct list_head list; - struct task_struct *task; - enum rwsem_waiter_type type; -}; - -enum rwsem_wake_type { - RWSEM_WAKE_ANY, /* Wake whatever's at head of wait list */ - RWSEM_WAKE_READERS, /* Wake readers only */ - RWSEM_WAKE_READ_OWNED /* Waker thread holds the read lock */ -}; - -/* - * handle the lock release when processes blocked on it that can now run - * - if we come here from up_xxxx(), then: - * - the 'active part' of count (&0x0000ffff) reached 0 (but may have changed) - * - the 'waiting part' of count (&0xffff0000) is -ve (and will still be so) - * - there must be someone on the queue - * - the wait_lock must be held by the caller - * - tasks are marked for wakeup, the caller must later invoke wake_up_q() - * to actually wakeup the blocked task(s) and drop the reference count, - * preferably when the wait_lock is released - * - woken process blocks are discarded from the list after having task zeroed - * - writers are only marked woken if downgrading is false - */ -static void __rwsem_mark_wake(struct rw_semaphore *sem, - enum rwsem_wake_type wake_type, - struct wake_q_head *wake_q) -{ - struct rwsem_waiter *waiter, *tmp; - long oldcount, woken = 0, adjustment = 0; - struct list_head wlist; - - /* - * Take a peek at the queue head waiter such that we can determine - * the wakeup(s) to perform. - */ - waiter = list_first_entry(&sem->wait_list, struct rwsem_waiter, list); - - if (waiter->type == RWSEM_WAITING_FOR_WRITE) { - if (wake_type == RWSEM_WAKE_ANY) { - /* - * Mark writer at the front of the queue for wakeup. - * Until the task is actually later awoken later by - * the caller, other writers are able to steal it. - * Readers, on the other hand, will block as they - * will notice the queued writer. - */ - wake_q_add(wake_q, waiter->task); - lockevent_inc(rwsem_wake_writer); - } - - return; - } - - /* - * Writers might steal the lock before we grant it to the next reader. - * We prefer to do the first reader grant before counting readers - * so we can bail out early if a writer stole the lock. - */ - if (wake_type != RWSEM_WAKE_READ_OWNED) { - adjustment = RWSEM_ACTIVE_READ_BIAS; - try_reader_grant: - oldcount = atomic_long_fetch_add(adjustment, &sem->count); - if (unlikely(oldcount < RWSEM_WAITING_BIAS)) { - /* - * If the count is still less than RWSEM_WAITING_BIAS - * after removing the adjustment, it is assumed that - * a writer has stolen the lock. We have to undo our - * reader grant. - */ - if (atomic_long_add_return(-adjustment, &sem->count) < - RWSEM_WAITING_BIAS) - return; - - /* Last active locker left. Retry waking readers. */ - goto try_reader_grant; - } - /* - * Set it to reader-owned to give spinners an early - * indication that readers now have the lock. - */ - __rwsem_set_reader_owned(sem, waiter->task); - } - - /* - * Grant an infinite number of read locks to the readers at the front - * of the queue. We know that woken will be at least 1 as we accounted - * for above. Note we increment the 'active part' of the count by the - * number of readers before waking any processes up. - * - * We have to do wakeup in 2 passes to prevent the possibility that - * the reader count may be decremented before it is incremented. It - * is because the to-be-woken waiter may not have slept yet. So it - * may see waiter->task got cleared, finish its critical section and - * do an unlock before the reader count increment. - * - * 1) Collect the read-waiters in a separate list, count them and - * fully increment the reader count in rwsem. - * 2) For each waiters in the new list, clear waiter->task and - * put them into wake_q to be woken up later. - */ - list_for_each_entry(waiter, &sem->wait_list, list) { - if (waiter->type == RWSEM_WAITING_FOR_WRITE) - break; - - woken++; - } - list_cut_before(&wlist, &sem->wait_list, &waiter->list); - - adjustment = woken * RWSEM_ACTIVE_READ_BIAS - adjustment; - lockevent_cond_inc(rwsem_wake_reader, woken); - if (list_empty(&sem->wait_list)) { - /* hit end of list above */ - adjustment -= RWSEM_WAITING_BIAS; - } - - if (adjustment) - atomic_long_add(adjustment, &sem->count); - - /* 2nd pass */ - list_for_each_entry_safe(waiter, tmp, &wlist, list) { - struct task_struct *tsk; - - tsk = waiter->task; - get_task_struct(tsk); - - /* - * Ensure calling get_task_struct() before setting the reader - * waiter to nil such that rwsem_down_read_failed() cannot - * race with do_exit() by always holding a reference count - * to the task to wakeup. - */ - smp_store_release(&waiter->task, NULL); - /* - * Ensure issuing the wakeup (either by us or someone else) - * after setting the reader waiter to nil. - */ - wake_q_add_safe(wake_q, tsk); - } -} - -/* - * This function must be called with the sem->wait_lock held to prevent - * race conditions between checking the rwsem wait list and setting the - * sem->count accordingly. - */ -static inline bool rwsem_try_write_lock(long count, struct rw_semaphore *sem) -{ - /* - * Avoid trying to acquire write lock if count isn't RWSEM_WAITING_BIAS. - */ - if (count != RWSEM_WAITING_BIAS) - return false; - - /* - * Acquire the lock by trying to set it to ACTIVE_WRITE_BIAS. If there - * are other tasks on the wait list, we need to add on WAITING_BIAS. - */ - count = list_is_singular(&sem->wait_list) ? - RWSEM_ACTIVE_WRITE_BIAS : - RWSEM_ACTIVE_WRITE_BIAS + RWSEM_WAITING_BIAS; - - if (atomic_long_cmpxchg_acquire(&sem->count, RWSEM_WAITING_BIAS, count) - == RWSEM_WAITING_BIAS) { - rwsem_set_owner(sem); - return true; - } - - return false; -} - -#ifdef CONFIG_RWSEM_SPIN_ON_OWNER -/* - * Try to acquire write lock before the writer has been put on wait queue. - */ -static inline bool rwsem_try_write_lock_unqueued(struct rw_semaphore *sem) -{ - long count = atomic_long_read(&sem->count); - - while (!count || count == RWSEM_WAITING_BIAS) { - if (atomic_long_try_cmpxchg_acquire(&sem->count, &count, - count + RWSEM_ACTIVE_WRITE_BIAS)) { - rwsem_set_owner(sem); - lockevent_inc(rwsem_opt_wlock); - return true; - } - } - return false; -} - -static inline bool owner_on_cpu(struct task_struct *owner) -{ - /* - * As lock holder preemption issue, we both skip spinning if - * task is not on cpu or its cpu is preempted - */ - return owner->on_cpu && !vcpu_is_preempted(task_cpu(owner)); -} - -static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem) -{ - struct task_struct *owner; - bool ret = true; - - BUILD_BUG_ON(!rwsem_has_anonymous_owner(RWSEM_OWNER_UNKNOWN)); - - if (need_resched()) - return false; - - rcu_read_lock(); - owner = READ_ONCE(sem->owner); - if (owner) { - ret = is_rwsem_owner_spinnable(owner) && - owner_on_cpu(owner); - } - rcu_read_unlock(); - return ret; -} - -/* - * Return true only if we can still spin on the owner field of the rwsem. - */ -static noinline bool rwsem_spin_on_owner(struct rw_semaphore *sem) -{ - struct task_struct *owner = READ_ONCE(sem->owner); - - if (!is_rwsem_owner_spinnable(owner)) - return false; - - rcu_read_lock(); - while (owner && (READ_ONCE(sem->owner) == owner)) { - /* - * Ensure we emit the owner->on_cpu, dereference _after_ - * checking sem->owner still matches owner, if that fails, - * owner might point to free()d memory, if it still matches, - * the rcu_read_lock() ensures the memory stays valid. - */ - barrier(); - - /* - * abort spinning when need_resched or owner is not running or - * owner's cpu is preempted. - */ - if (need_resched() || !owner_on_cpu(owner)) { - rcu_read_unlock(); - return false; - } - - cpu_relax(); - } - rcu_read_unlock(); - - /* - * If there is a new owner or the owner is not set, we continue - * spinning. - */ - return is_rwsem_owner_spinnable(READ_ONCE(sem->owner)); -} - -static bool rwsem_optimistic_spin(struct rw_semaphore *sem) -{ - bool taken = false; - - preempt_disable(); - - /* sem->wait_lock should not be held when doing optimistic spinning */ - if (!rwsem_can_spin_on_owner(sem)) - goto done; - - if (!osq_lock(&sem->osq)) - goto done; - - /* - * Optimistically spin on the owner field and attempt to acquire the - * lock whenever the owner changes. Spinning will be stopped when: - * 1) the owning writer isn't running; or - * 2) readers own the lock as we can't determine if they are - * actively running or not. - */ - while (rwsem_spin_on_owner(sem)) { - /* - * Try to acquire the lock - */ - if (rwsem_try_write_lock_unqueued(sem)) { - taken = true; - break; - } - - /* - * When there's no owner, we might have preempted between the - * owner acquiring the lock and setting the owner field. If - * we're an RT task that will live-lock because we won't let - * the owner complete. - */ - if (!sem->owner && (need_resched() || rt_task(current))) - break; - - /* - * The cpu_relax() call is a compiler barrier which forces - * everything in this loop to be re-loaded. We don't need - * memory barriers as we'll eventually observe the right - * values at the cost of a few extra spins. - */ - cpu_relax(); - } - osq_unlock(&sem->osq); -done: - preempt_enable(); - lockevent_cond_inc(rwsem_opt_fail, !taken); - return taken; -} - -/* - * Return true if the rwsem has active spinner - */ -static inline bool rwsem_has_spinner(struct rw_semaphore *sem) -{ - return osq_is_locked(&sem->osq); -} - -#else -static bool rwsem_optimistic_spin(struct rw_semaphore *sem) -{ - return false; -} - -static inline bool rwsem_has_spinner(struct rw_semaphore *sem) -{ - return false; -} -#endif - -/* - * Wait for the read lock to be granted - */ -static inline struct rw_semaphore __sched * -__rwsem_down_read_failed_common(struct rw_semaphore *sem, int state) -{ - long count, adjustment = -RWSEM_ACTIVE_READ_BIAS; - struct rwsem_waiter waiter; - DEFINE_WAKE_Q(wake_q); - - waiter.task = current; - waiter.type = RWSEM_WAITING_FOR_READ; - - raw_spin_lock_irq(&sem->wait_lock); - if (list_empty(&sem->wait_list)) { - /* - * In case the wait queue is empty and the lock isn't owned - * by a writer, this reader can exit the slowpath and return - * immediately as its RWSEM_ACTIVE_READ_BIAS has already - * been set in the count. - */ - if (atomic_long_read(&sem->count) >= 0) { - raw_spin_unlock_irq(&sem->wait_lock); - rwsem_set_reader_owned(sem); - lockevent_inc(rwsem_rlock_fast); - return sem; - } - adjustment += RWSEM_WAITING_BIAS; - } - list_add_tail(&waiter.list, &sem->wait_list); - - /* we're now waiting on the lock, but no longer actively locking */ - count = atomic_long_add_return(adjustment, &sem->count); - - /* - * If there are no active locks, wake the front queued process(es). - * - * If there are no writers and we are first in the queue, - * wake our own waiter to join the existing active readers ! - */ - if (count == RWSEM_WAITING_BIAS || - (count > RWSEM_WAITING_BIAS && - adjustment != -RWSEM_ACTIVE_READ_BIAS)) - __rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q); - - raw_spin_unlock_irq(&sem->wait_lock); - wake_up_q(&wake_q); - - /* wait to be given the lock */ - while (true) { - set_current_state(state); - if (!waiter.task) - break; - if (signal_pending_state(state, current)) { - raw_spin_lock_irq(&sem->wait_lock); - if (waiter.task) - goto out_nolock; - raw_spin_unlock_irq(&sem->wait_lock); - break; - } - schedule(); - lockevent_inc(rwsem_sleep_reader); - } - - __set_current_state(TASK_RUNNING); - lockevent_inc(rwsem_rlock); - return sem; -out_nolock: - list_del(&waiter.list); - if (list_empty(&sem->wait_list)) - atomic_long_add(-RWSEM_WAITING_BIAS, &sem->count); - raw_spin_unlock_irq(&sem->wait_lock); - __set_current_state(TASK_RUNNING); - lockevent_inc(rwsem_rlock_fail); - return ERR_PTR(-EINTR); -} - -__visible struct rw_semaphore * __sched -rwsem_down_read_failed(struct rw_semaphore *sem) -{ - return __rwsem_down_read_failed_common(sem, TASK_UNINTERRUPTIBLE); -} -EXPORT_SYMBOL(rwsem_down_read_failed); - -__visible struct rw_semaphore * __sched -rwsem_down_read_failed_killable(struct rw_semaphore *sem) -{ - return __rwsem_down_read_failed_common(sem, TASK_KILLABLE); -} -EXPORT_SYMBOL(rwsem_down_read_failed_killable); - -/* - * Wait until we successfully acquire the write lock - */ -static inline struct rw_semaphore * -__rwsem_down_write_failed_common(struct rw_semaphore *sem, int state) -{ - long count; - bool waiting = true; /* any queued threads before us */ - struct rwsem_waiter waiter; - struct rw_semaphore *ret = sem; - DEFINE_WAKE_Q(wake_q); - - /* undo write bias from down_write operation, stop active locking */ - count = atomic_long_sub_return(RWSEM_ACTIVE_WRITE_BIAS, &sem->count); - - /* do optimistic spinning and steal lock if possible */ - if (rwsem_optimistic_spin(sem)) - return sem; - - /* - * Optimistic spinning failed, proceed to the slowpath - * and block until we can acquire the sem. - */ - waiter.task = current; - waiter.type = RWSEM_WAITING_FOR_WRITE; - - raw_spin_lock_irq(&sem->wait_lock); - - /* account for this before adding a new element to the list */ - if (list_empty(&sem->wait_list)) - waiting = false; - - list_add_tail(&waiter.list, &sem->wait_list); - - /* we're now waiting on the lock, but no longer actively locking */ - if (waiting) { - count = atomic_long_read(&sem->count); - - /* - * If there were already threads queued before us and there are - * no active writers, the lock must be read owned; so we try to - * wake any read locks that were queued ahead of us. - */ - if (count > RWSEM_WAITING_BIAS) { - __rwsem_mark_wake(sem, RWSEM_WAKE_READERS, &wake_q); - /* - * The wakeup is normally called _after_ the wait_lock - * is released, but given that we are proactively waking - * readers we can deal with the wake_q overhead as it is - * similar to releasing and taking the wait_lock again - * for attempting rwsem_try_write_lock(). - */ - wake_up_q(&wake_q); - - /* - * Reinitialize wake_q after use. - */ - wake_q_init(&wake_q); - } - - } else - count = atomic_long_add_return(RWSEM_WAITING_BIAS, &sem->count); - - /* wait until we successfully acquire the lock */ - set_current_state(state); - while (true) { - if (rwsem_try_write_lock(count, sem)) - break; - raw_spin_unlock_irq(&sem->wait_lock); - - /* Block until there are no active lockers. */ - do { - if (signal_pending_state(state, current)) - goto out_nolock; - - schedule(); - lockevent_inc(rwsem_sleep_writer); - set_current_state(state); - } while ((count = atomic_long_read(&sem->count)) & RWSEM_ACTIVE_MASK); - - raw_spin_lock_irq(&sem->wait_lock); - } - __set_current_state(TASK_RUNNING); - list_del(&waiter.list); - raw_spin_unlock_irq(&sem->wait_lock); - lockevent_inc(rwsem_wlock); - - return ret; - -out_nolock: - __set_current_state(TASK_RUNNING); - raw_spin_lock_irq(&sem->wait_lock); - list_del(&waiter.list); - if (list_empty(&sem->wait_list)) - atomic_long_add(-RWSEM_WAITING_BIAS, &sem->count); - else - __rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q); - raw_spin_unlock_irq(&sem->wait_lock); - wake_up_q(&wake_q); - lockevent_inc(rwsem_wlock_fail); - - return ERR_PTR(-EINTR); -} - -__visible struct rw_semaphore * __sched -rwsem_down_write_failed(struct rw_semaphore *sem) -{ - return __rwsem_down_write_failed_common(sem, TASK_UNINTERRUPTIBLE); -} -EXPORT_SYMBOL(rwsem_down_write_failed); - -__visible struct rw_semaphore * __sched -rwsem_down_write_failed_killable(struct rw_semaphore *sem) -{ - return __rwsem_down_write_failed_common(sem, TASK_KILLABLE); -} -EXPORT_SYMBOL(rwsem_down_write_failed_killable); - -/* - * handle waking up a waiter on the semaphore - * - up_read/up_write has decremented the active part of count if we come here - */ -__visible -struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem) -{ - unsigned long flags; - DEFINE_WAKE_Q(wake_q); - - /* - * __rwsem_down_write_failed_common(sem) - * rwsem_optimistic_spin(sem) - * osq_unlock(sem->osq) - * ... - * atomic_long_add_return(&sem->count) - * - * - VS - - * - * __up_write() - * if (atomic_long_sub_return_release(&sem->count) < 0) - * rwsem_wake(sem) - * osq_is_locked(&sem->osq) - * - * And __up_write() must observe !osq_is_locked() when it observes the - * atomic_long_add_return() in order to not miss a wakeup. - * - * This boils down to: - * - * [S.rel] X = 1 [RmW] r0 = (Y += 0) - * MB RMB - * [RmW] Y += 1 [L] r1 = X - * - * exists (r0=1 /\ r1=0) - */ - smp_rmb(); - - /* - * If a spinner is present, it is not necessary to do the wakeup. - * Try to do wakeup only if the trylock succeeds to minimize - * spinlock contention which may introduce too much delay in the - * unlock operation. - * - * spinning writer up_write/up_read caller - * --------------- ----------------------- - * [S] osq_unlock() [L] osq - * MB RMB - * [RmW] rwsem_try_write_lock() [RmW] spin_trylock(wait_lock) - * - * Here, it is important to make sure that there won't be a missed - * wakeup while the rwsem is free and the only spinning writer goes - * to sleep without taking the rwsem. Even when the spinning writer - * is just going to break out of the waiting loop, it will still do - * a trylock in rwsem_down_write_failed() before sleeping. IOW, if - * rwsem_has_spinner() is true, it will guarantee at least one - * trylock attempt on the rwsem later on. - */ - if (rwsem_has_spinner(sem)) { - /* - * The smp_rmb() here is to make sure that the spinner - * state is consulted before reading the wait_lock. - */ - smp_rmb(); - if (!raw_spin_trylock_irqsave(&sem->wait_lock, flags)) - return sem; - goto locked; - } - raw_spin_lock_irqsave(&sem->wait_lock, flags); -locked: - - if (!list_empty(&sem->wait_list)) - __rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q); - - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - wake_up_q(&wake_q); - - return sem; -} -EXPORT_SYMBOL(rwsem_wake); - -/* - * downgrade a write lock into a read lock - * - caller incremented waiting part of count and discovered it still negative - * - just wake up any readers at the front of the queue - */ -__visible -struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem) -{ - unsigned long flags; - DEFINE_WAKE_Q(wake_q); - - raw_spin_lock_irqsave(&sem->wait_lock, flags); - - if (!list_empty(&sem->wait_list)) - __rwsem_mark_wake(sem, RWSEM_WAKE_READ_OWNED, &wake_q); - - raw_spin_unlock_irqrestore(&sem->wait_lock, flags); - wake_up_q(&wake_q); - - return sem; -} -EXPORT_SYMBOL(rwsem_downgrade_wake); diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index ccbf18f560ff..37524a47f002 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -3,17 +3,1438 @@ * * Written by David Howells (dhowells@redhat.com). * Derived from asm-i386/semaphore.h + * + * Writer lock-stealing by Alex Shi <alex.shi@intel.com> + * and Michel Lespinasse <walken@google.com> + * + * Optimistic spinning by Tim Chen <tim.c.chen@intel.com> + * and Davidlohr Bueso <davidlohr@hp.com>. Based on mutexes. + * + * Rwsem count bit fields re-definition and rwsem rearchitecture by + * Waiman Long <longman@redhat.com> and + * Peter Zijlstra <peterz@infradead.org>. */ #include <linux/types.h> #include <linux/kernel.h> #include <linux/sched.h> +#include <linux/sched/rt.h> +#include <linux/sched/task.h> #include <linux/sched/debug.h> +#include <linux/sched/wake_q.h> +#include <linux/sched/signal.h> +#include <linux/sched/clock.h> #include <linux/export.h> #include <linux/rwsem.h> #include <linux/atomic.h> #include "rwsem.h" +#include "lock_events.h" + +/* + * The least significant 3 bits of the owner value has the following + * meanings when set. + * - Bit 0: RWSEM_READER_OWNED - The rwsem is owned by readers + * - Bit 1: RWSEM_RD_NONSPINNABLE - Readers cannot spin on this lock. + * - Bit 2: RWSEM_WR_NONSPINNABLE - Writers cannot spin on this lock. + * + * When the rwsem is either owned by an anonymous writer, or it is + * reader-owned, but a spinning writer has timed out, both nonspinnable + * bits will be set to disable optimistic spinning by readers and writers. + * In the later case, the last unlocking reader should then check the + * writer nonspinnable bit and clear it only to give writers preference + * to acquire the lock via optimistic spinning, but not readers. Similar + * action is also done in the reader slowpath. + + * When a writer acquires a rwsem, it puts its task_struct pointer + * into the owner field. It is cleared after an unlock. + * + * When a reader acquires a rwsem, it will also puts its task_struct + * pointer into the owner field with the RWSEM_READER_OWNED bit set. + * On unlock, the owner field will largely be left untouched. So + * for a free or reader-owned rwsem, the owner value may contain + * information about the last reader that acquires the rwsem. + * + * That information may be helpful in debugging cases where the system + * seems to hang on a reader owned rwsem especially if only one reader + * is involved. Ideally we would like to track all the readers that own + * a rwsem, but the overhead is simply too big. + * + * Reader optimistic spinning is helpful when the reader critical section + * is short and there aren't that many readers around. It makes readers + * relatively more preferred than writers. When a writer times out spinning + * on a reader-owned lock and set the nospinnable bits, there are two main + * reasons for that. + * + * 1) The reader critical section is long, perhaps the task sleeps after + * acquiring the read lock. + * 2) There are just too many readers contending the lock causing it to + * take a while to service all of them. + * + * In the former case, long reader critical section will impede the progress + * of writers which is usually more important for system performance. In + * the later case, reader optimistic spinning tends to make the reader + * groups that contain readers that acquire the lock together smaller + * leading to more of them. That may hurt performance in some cases. In + * other words, the setting of nonspinnable bits indicates that reader + * optimistic spinning may not be helpful for those workloads that cause + * it. + * + * Therefore, any writers that had observed the setting of the writer + * nonspinnable bit for a given rwsem after they fail to acquire the lock + * via optimistic spinning will set the reader nonspinnable bit once they + * acquire the write lock. Similarly, readers that observe the setting + * of reader nonspinnable bit at slowpath entry will set the reader + * nonspinnable bits when they acquire the read lock via the wakeup path. + * + * Once the reader nonspinnable bit is on, it will only be reset when + * a writer is able to acquire the rwsem in the fast path or somehow a + * reader or writer in the slowpath doesn't observe the nonspinable bit. + * + * This is to discourage reader optmistic spinning on that particular + * rwsem and make writers more preferred. This adaptive disabling of reader + * optimistic spinning will alleviate the negative side effect of this + * feature. + */ +#define RWSEM_READER_OWNED (1UL << 0) +#define RWSEM_RD_NONSPINNABLE (1UL << 1) +#define RWSEM_WR_NONSPINNABLE (1UL << 2) +#define RWSEM_NONSPINNABLE (RWSEM_RD_NONSPINNABLE | RWSEM_WR_NONSPINNABLE) +#define RWSEM_OWNER_FLAGS_MASK (RWSEM_READER_OWNED | RWSEM_NONSPINNABLE) + +#ifdef CONFIG_DEBUG_RWSEMS +# define DEBUG_RWSEMS_WARN_ON(c, sem) do { \ + if (!debug_locks_silent && \ + WARN_ONCE(c, "DEBUG_RWSEMS_WARN_ON(%s): count = 0x%lx, owner = 0x%lx, curr 0x%lx, list %sempty\n",\ + #c, atomic_long_read(&(sem)->count), \ + atomic_long_read(&(sem)->owner), (long)current, \ + list_empty(&(sem)->wait_list) ? "" : "not ")) \ + debug_locks_off(); \ + } while (0) +#else +# define DEBUG_RWSEMS_WARN_ON(c, sem) +#endif + +/* + * On 64-bit architectures, the bit definitions of the count are: + * + * Bit 0 - writer locked bit + * Bit 1 - waiters present bit + * Bit 2 - lock handoff bit + * Bits 3-7 - reserved + * Bits 8-62 - 55-bit reader count + * Bit 63 - read fail bit + * + * On 32-bit architectures, the bit definitions of the count are: + * + * Bit 0 - writer locked bit + * Bit 1 - waiters present bit + * Bit 2 - lock handoff bit + * Bits 3-7 - reserved + * Bits 8-30 - 23-bit reader count + * Bit 31 - read fail bit + * + * It is not likely that the most significant bit (read fail bit) will ever + * be set. This guard bit is still checked anyway in the down_read() fastpath + * just in case we need to use up more of the reader bits for other purpose + * in the future. + * + * atomic_long_fetch_add() is used to obtain reader lock, whereas + * atomic_long_cmpxchg() will be used to obtain writer lock. + * + * There are three places where the lock handoff bit may be set or cleared. + * 1) rwsem_mark_wake() for readers. + * 2) rwsem_try_write_lock() for writers. + * 3) Error path of rwsem_down_write_slowpath(). + * + * For all the above cases, wait_lock will be held. A writer must also + * be the first one in the wait_list to be eligible for setting the handoff + * bit. So concurrent setting/clearing of handoff bit is not possible. + */ +#define RWSEM_WRITER_LOCKED (1UL << 0) +#define RWSEM_FLAG_WAITERS (1UL << 1) +#define RWSEM_FLAG_HANDOFF (1UL << 2) +#define RWSEM_FLAG_READFAIL (1UL << (BITS_PER_LONG - 1)) + +#define RWSEM_READER_SHIFT 8 +#define RWSEM_READER_BIAS (1UL << RWSEM_READER_SHIFT) +#define RWSEM_READER_MASK (~(RWSEM_READER_BIAS - 1)) +#define RWSEM_WRITER_MASK RWSEM_WRITER_LOCKED +#define RWSEM_LOCK_MASK (RWSEM_WRITER_MASK|RWSEM_READER_MASK) +#define RWSEM_READ_FAILED_MASK (RWSEM_WRITER_MASK|RWSEM_FLAG_WAITERS|\ + RWSEM_FLAG_HANDOFF|RWSEM_FLAG_READFAIL) + +/* + * All writes to owner are protected by WRITE_ONCE() to make sure that + * store tearing can't happen as optimistic spinners may read and use + * the owner value concurrently without lock. Read from owner, however, + * may not need READ_ONCE() as long as the pointer value is only used + * for comparison and isn't being dereferenced. + */ +static inline void rwsem_set_owner(struct rw_semaphore *sem) +{ + atomic_long_set(&sem->owner, (long)current); +} + +static inline void rwsem_clear_owner(struct rw_semaphore *sem) +{ + atomic_long_set(&sem->owner, 0); +} + +/* + * Test the flags in the owner field. + */ +static inline bool rwsem_test_oflags(struct rw_semaphore *sem, long flags) +{ + return atomic_long_read(&sem->owner) & flags; +} + +/* + * The task_struct pointer of the last owning reader will be left in + * the owner field. + * + * Note that the owner value just indicates the task has owned the rwsem + * previously, it may not be the real owner or one of the real owners + * anymore when that field is examined, so take it with a grain of salt. + * + * The reader non-spinnable bit is preserved. + */ +static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem, + struct task_struct *owner) +{ + unsigned long val = (unsigned long)owner | RWSEM_READER_OWNED | + (atomic_long_read(&sem->owner) & RWSEM_RD_NONSPINNABLE); + + atomic_long_set(&sem->owner, val); +} + +static inline void rwsem_set_reader_owned(struct rw_semaphore *sem) +{ + __rwsem_set_reader_owned(sem, current); +} + +/* + * Return true if the rwsem is owned by a reader. + */ +static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem) +{ +#ifdef CONFIG_DEBUG_RWSEMS + /* + * Check the count to see if it is write-locked. + */ + long count = atomic_long_read(&sem->count); + + if (count & RWSEM_WRITER_MASK) + return false; +#endif + return rwsem_test_oflags(sem, RWSEM_READER_OWNED); +} + +#ifdef CONFIG_DEBUG_RWSEMS +/* + * With CONFIG_DEBUG_RWSEMS configured, it will make sure that if there + * is a task pointer in owner of a reader-owned rwsem, it will be the + * real owner or one of the real owners. The only exception is when the + * unlock is done by up_read_non_owner(). + */ +static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem) +{ + unsigned long val = atomic_long_read(&sem->owner); + + while ((val & ~RWSEM_OWNER_FLAGS_MASK) == (unsigned long)current) { + if (atomic_long_try_cmpxchg(&sem->owner, &val, + val & RWSEM_OWNER_FLAGS_MASK)) + return; + } +} +#else +static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem) +{ +} +#endif + +/* + * Set the RWSEM_NONSPINNABLE bits if the RWSEM_READER_OWNED flag + * remains set. Otherwise, the operation will be aborted. + */ +static inline void rwsem_set_nonspinnable(struct rw_semaphore *sem) +{ + unsigned long owner = atomic_long_read(&sem->owner); + + do { + if (!(owner & RWSEM_READER_OWNED)) + break; + if (owner & RWSEM_NONSPINNABLE) + break; + } while (!atomic_long_try_cmpxchg(&sem->owner, &owner, + owner | RWSEM_NONSPINNABLE)); +} + +static inline bool rwsem_read_trylock(struct rw_semaphore *sem) +{ + long cnt = atomic_long_add_return_acquire(RWSEM_READER_BIAS, &sem->count); + if (WARN_ON_ONCE(cnt < 0)) + rwsem_set_nonspinnable(sem); + return !(cnt & RWSEM_READ_FAILED_MASK); +} + +/* + * Return just the real task structure pointer of the owner + */ +static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem) +{ + return (struct task_struct *) + (atomic_long_read(&sem->owner) & ~RWSEM_OWNER_FLAGS_MASK); +} + +/* + * Return the real task structure pointer of the owner and the embedded + * flags in the owner. pflags must be non-NULL. + */ +static inline struct task_struct * +rwsem_owner_flags(struct rw_semaphore *sem, unsigned long *pflags) +{ + unsigned long owner = atomic_long_read(&sem->owner); + + *pflags = owner & RWSEM_OWNER_FLAGS_MASK; + return (struct task_struct *)(owner & ~RWSEM_OWNER_FLAGS_MASK); +} + +/* + * Guide to the rw_semaphore's count field. + * + * When the RWSEM_WRITER_LOCKED bit in count is set, the lock is owned + * by a writer. + * + * The lock is owned by readers when + * (1) the RWSEM_WRITER_LOCKED isn't set in count, + * (2) some of the reader bits are set in count, and + * (3) the owner field has RWSEM_READ_OWNED bit set. + * + * Having some reader bits set is not enough to guarantee a readers owned + * lock as the readers may be in the process of backing out from the count + * and a writer has just released the lock. So another writer may steal + * the lock immediately after that. + */ + +/* + * Initialize an rwsem: + */ +void __init_rwsem(struct rw_semaphore *sem, const char *name, + struct lock_class_key *key) +{ +#ifdef CONFIG_DEBUG_LOCK_ALLOC + /* + * Make sure we are not reinitializing a held semaphore: + */ + debug_check_no_locks_freed((void *)sem, sizeof(*sem)); + lockdep_init_map(&sem->dep_map, name, key, 0); +#endif + atomic_long_set(&sem->count, RWSEM_UNLOCKED_VALUE); + raw_spin_lock_init(&sem->wait_lock); + INIT_LIST_HEAD(&sem->wait_list); + atomic_long_set(&sem->owner, 0L); +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER + osq_lock_init(&sem->osq); +#endif +} +EXPORT_SYMBOL(__init_rwsem); + +enum rwsem_waiter_type { + RWSEM_WAITING_FOR_WRITE, + RWSEM_WAITING_FOR_READ +}; + +struct rwsem_waiter { + struct list_head list; + struct task_struct *task; + enum rwsem_waiter_type type; + unsigned long timeout; + unsigned long last_rowner; +}; +#define rwsem_first_waiter(sem) \ + list_first_entry(&sem->wait_list, struct rwsem_waiter, list) + +enum rwsem_wake_type { + RWSEM_WAKE_ANY, /* Wake whatever's at head of wait list */ + RWSEM_WAKE_READERS, /* Wake readers only */ + RWSEM_WAKE_READ_OWNED /* Waker thread holds the read lock */ +}; + +enum writer_wait_state { + WRITER_NOT_FIRST, /* Writer is not first in wait list */ + WRITER_FIRST, /* Writer is first in wait list */ + WRITER_HANDOFF /* Writer is first & handoff needed */ +}; + +/* + * The typical HZ value is either 250 or 1000. So set the minimum waiting + * time to at least 4ms or 1 jiffy (if it is higher than 4ms) in the wait + * queue before initiating the handoff protocol. + */ +#define RWSEM_WAIT_TIMEOUT DIV_ROUND_UP(HZ, 250) + +/* + * Magic number to batch-wakeup waiting readers, even when writers are + * also present in the queue. This both limits the amount of work the + * waking thread must do and also prevents any potential counter overflow, + * however unlikely. + */ +#define MAX_READERS_WAKEUP 0x100 + +/* + * handle the lock release when processes blocked on it that can now run + * - if we come here from up_xxxx(), then the RWSEM_FLAG_WAITERS bit must + * have been set. + * - there must be someone on the queue + * - the wait_lock must be held by the caller + * - tasks are marked for wakeup, the caller must later invoke wake_up_q() + * to actually wakeup the blocked task(s) and drop the reference count, + * preferably when the wait_lock is released + * - woken process blocks are discarded from the list after having task zeroed + * - writers are only marked woken if downgrading is false + */ +static void rwsem_mark_wake(struct rw_semaphore *sem, + enum rwsem_wake_type wake_type, + struct wake_q_head *wake_q) +{ + struct rwsem_waiter *waiter, *tmp; + long oldcount, woken = 0, adjustment = 0; + struct list_head wlist; + + lockdep_assert_held(&sem->wait_lock); + + /* + * Take a peek at the queue head waiter such that we can determine + * the wakeup(s) to perform. + */ + waiter = rwsem_first_waiter(sem); + + if (waiter->type == RWSEM_WAITING_FOR_WRITE) { + if (wake_type == RWSEM_WAKE_ANY) { + /* + * Mark writer at the front of the queue for wakeup. + * Until the task is actually later awoken later by + * the caller, other writers are able to steal it. + * Readers, on the other hand, will block as they + * will notice the queued writer. + */ + wake_q_add(wake_q, waiter->task); + lockevent_inc(rwsem_wake_writer); + } + + return; + } + + /* + * No reader wakeup if there are too many of them already. + */ + if (unlikely(atomic_long_read(&sem->count) < 0)) + return; + + /* + * Writers might steal the lock before we grant it to the next reader. + * We prefer to do the first reader grant before counting readers + * so we can bail out early if a writer stole the lock. + */ + if (wake_type != RWSEM_WAKE_READ_OWNED) { + struct task_struct *owner; + + adjustment = RWSEM_READER_BIAS; + oldcount = atomic_long_fetch_add(adjustment, &sem->count); + if (unlikely(oldcount & RWSEM_WRITER_MASK)) { + /* + * When we've been waiting "too" long (for writers + * to give up the lock), request a HANDOFF to + * force the issue. + */ + if (!(oldcount & RWSEM_FLAG_HANDOFF) && + time_after(jiffies, waiter->timeout)) { + adjustment -= RWSEM_FLAG_HANDOFF; + lockevent_inc(rwsem_rlock_handoff); + } + + atomic_long_add(-adjustment, &sem->count); + return; + } + /* + * Set it to reader-owned to give spinners an early + * indication that readers now have the lock. + * The reader nonspinnable bit seen at slowpath entry of + * the reader is copied over. + */ + owner = waiter->task; + if (waiter->last_rowner & RWSEM_RD_NONSPINNABLE) { + owner = (void *)((unsigned long)owner | RWSEM_RD_NONSPINNABLE); + lockevent_inc(rwsem_opt_norspin); + } + __rwsem_set_reader_owned(sem, owner); + } + + /* + * Grant up to MAX_READERS_WAKEUP read locks to all the readers in the + * queue. We know that the woken will be at least 1 as we accounted + * for above. Note we increment the 'active part' of the count by the + * number of readers before waking any processes up. + * + * This is an adaptation of the phase-fair R/W locks where at the + * reader phase (first waiter is a reader), all readers are eligible + * to acquire the lock at the same time irrespective of their order + * in the queue. The writers acquire the lock according to their + * order in the queue. + * + * We have to do wakeup in 2 passes to prevent the possibility that + * the reader count may be decremented before it is incremented. It + * is because the to-be-woken waiter may not have slept yet. So it + * may see waiter->task got cleared, finish its critical section and + * do an unlock before the reader count increment. + * + * 1) Collect the read-waiters in a separate list, count them and + * fully increment the reader count in rwsem. + * 2) For each waiters in the new list, clear waiter->task and + * put them into wake_q to be woken up later. + */ + INIT_LIST_HEAD(&wlist); + list_for_each_entry_safe(waiter, tmp, &sem->wait_list, list) { + if (waiter->type == RWSEM_WAITING_FOR_WRITE) + continue; + + woken++; + list_move_tail(&waiter->list, &wlist); + + /* + * Limit # of readers that can be woken up per wakeup call. + */ + if (woken >= MAX_READERS_WAKEUP) + break; + } + + adjustment = woken * RWSEM_READER_BIAS - adjustment; + lockevent_cond_inc(rwsem_wake_reader, woken); + if (list_empty(&sem->wait_list)) { + /* hit end of list above */ + adjustment -= RWSEM_FLAG_WAITERS; + } + + /* + * When we've woken a reader, we no longer need to force writers + * to give up the lock and we can clear HANDOFF. + */ + if (woken && (atomic_long_read(&sem->count) & RWSEM_FLAG_HANDOFF)) + adjustment -= RWSEM_FLAG_HANDOFF; + + if (adjustment) + atomic_long_add(adjustment, &sem->count); + + /* 2nd pass */ + list_for_each_entry_safe(waiter, tmp, &wlist, list) { + struct task_struct *tsk; + + tsk = waiter->task; + get_task_struct(tsk); + + /* + * Ensure calling get_task_struct() before setting the reader + * waiter to nil such that rwsem_down_read_slowpath() cannot + * race with do_exit() by always holding a reference count + * to the task to wakeup. + */ + smp_store_release(&waiter->task, NULL); + /* + * Ensure issuing the wakeup (either by us or someone else) + * after setting the reader waiter to nil. + */ + wake_q_add_safe(wake_q, tsk); + } +} + +/* + * This function must be called with the sem->wait_lock held to prevent + * race conditions between checking the rwsem wait list and setting the + * sem->count accordingly. + * + * If wstate is WRITER_HANDOFF, it will make sure that either the handoff + * bit is set or the lock is acquired with handoff bit cleared. + */ +static inline bool rwsem_try_write_lock(struct rw_semaphore *sem, + enum writer_wait_state wstate) +{ + long count, new; + + lockdep_assert_held(&sem->wait_lock); + + count = atomic_long_read(&sem->count); + do { + bool has_handoff = !!(count & RWSEM_FLAG_HANDOFF); + + if (has_handoff && wstate == WRITER_NOT_FIRST) + return false; + + new = count; + + if (count & RWSEM_LOCK_MASK) { + if (has_handoff || (wstate != WRITER_HANDOFF)) + return false; + + new |= RWSEM_FLAG_HANDOFF; + } else { + new |= RWSEM_WRITER_LOCKED; + new &= ~RWSEM_FLAG_HANDOFF; + + if (list_is_singular(&sem->wait_list)) + new &= ~RWSEM_FLAG_WAITERS; + } + } while (!atomic_long_try_cmpxchg_acquire(&sem->count, &count, new)); + + /* + * We have either acquired the lock with handoff bit cleared or + * set the handoff bit. + */ + if (new & RWSEM_FLAG_HANDOFF) + return false; + + rwsem_set_owner(sem); + return true; +} + +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER +/* + * Try to acquire read lock before the reader is put on wait queue. + * Lock acquisition isn't allowed if the rwsem is locked or a writer handoff + * is ongoing. + */ +static inline bool rwsem_try_read_lock_unqueued(struct rw_semaphore *sem) +{ + long count = atomic_long_read(&sem->count); + + if (count & (RWSEM_WRITER_MASK | RWSEM_FLAG_HANDOFF)) + return false; + + count = atomic_long_fetch_add_acquire(RWSEM_READER_BIAS, &sem->count); + if (!(count & (RWSEM_WRITER_MASK | RWSEM_FLAG_HANDOFF))) { + rwsem_set_reader_owned(sem); + lockevent_inc(rwsem_opt_rlock); + return true; + } + + /* Back out the change */ + atomic_long_add(-RWSEM_READER_BIAS, &sem->count); + return false; +} + +/* + * Try to acquire write lock before the writer has been put on wait queue. + */ +static inline bool rwsem_try_write_lock_unqueued(struct rw_semaphore *sem) +{ + long count = atomic_long_read(&sem->count); + + while (!(count & (RWSEM_LOCK_MASK|RWSEM_FLAG_HANDOFF))) { + if (atomic_long_try_cmpxchg_acquire(&sem->count, &count, + count | RWSEM_WRITER_LOCKED)) { + rwsem_set_owner(sem); + lockevent_inc(rwsem_opt_wlock); + return true; + } + } + return false; +} + +static inline bool owner_on_cpu(struct task_struct *owner) +{ + /* + * As lock holder preemption issue, we both skip spinning if + * task is not on cpu or its cpu is preempted + */ + return owner->on_cpu && !vcpu_is_preempted(task_cpu(owner)); +} + +static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem, + unsigned long nonspinnable) +{ + struct task_struct *owner; + unsigned long flags; + bool ret = true; + + BUILD_BUG_ON(!(RWSEM_OWNER_UNKNOWN & RWSEM_NONSPINNABLE)); + + if (need_resched()) { + lockevent_inc(rwsem_opt_fail); + return false; + } + + preempt_disable(); + rcu_read_lock(); + owner = rwsem_owner_flags(sem, &flags); + if ((flags & nonspinnable) || (owner && !owner_on_cpu(owner))) + ret = false; + rcu_read_unlock(); + preempt_enable(); + + lockevent_cond_inc(rwsem_opt_fail, !ret); + return ret; +} + +/* + * The rwsem_spin_on_owner() function returns the folowing 4 values + * depending on the lock owner state. + * OWNER_NULL : owner is currently NULL + * OWNER_WRITER: when owner changes and is a writer + * OWNER_READER: when owner changes and the new owner may be a reader. + * OWNER_NONSPINNABLE: + * when optimistic spinning has to stop because either the + * owner stops running, is unknown, or its timeslice has + * been used up. + */ +enum owner_state { + OWNER_NULL = 1 << 0, + OWNER_WRITER = 1 << 1, + OWNER_READER = 1 << 2, + OWNER_NONSPINNABLE = 1 << 3, +}; +#define OWNER_SPINNABLE (OWNER_NULL | OWNER_WRITER | OWNER_READER) + +static inline enum owner_state +rwsem_owner_state(struct task_struct *owner, unsigned long flags, unsigned long nonspinnable) +{ + if (flags & nonspinnable) + return OWNER_NONSPINNABLE; + + if (flags & RWSEM_READER_OWNED) + return OWNER_READER; + + return owner ? OWNER_WRITER : OWNER_NULL; +} + +static noinline enum owner_state +rwsem_spin_on_owner(struct rw_semaphore *sem, unsigned long nonspinnable) +{ + struct task_struct *new, *owner; + unsigned long flags, new_flags; + enum owner_state state; + + owner = rwsem_owner_flags(sem, &flags); + state = rwsem_owner_state(owner, flags, nonspinnable); + if (state != OWNER_WRITER) + return state; + + rcu_read_lock(); + for (;;) { + if (atomic_long_read(&sem->count) & RWSEM_FLAG_HANDOFF) { + state = OWNER_NONSPINNABLE; + break; + } + + new = rwsem_owner_flags(sem, &new_flags); + if ((new != owner) || (new_flags != flags)) { + state = rwsem_owner_state(new, new_flags, nonspinnable); + break; + } + + /* + * Ensure we emit the owner->on_cpu, dereference _after_ + * checking sem->owner still matches owner, if that fails, + * owner might point to free()d memory, if it still matches, + * the rcu_read_lock() ensures the memory stays valid. + */ + barrier(); + + if (need_resched() || !owner_on_cpu(owner)) { + state = OWNER_NONSPINNABLE; + break; + } + + cpu_relax(); + } + rcu_read_unlock(); + + return state; +} + +/* + * Calculate reader-owned rwsem spinning threshold for writer + * + * The more readers own the rwsem, the longer it will take for them to + * wind down and free the rwsem. So the empirical formula used to + * determine the actual spinning time limit here is: + * + * Spinning threshold = (10 + nr_readers/2)us + * + * The limit is capped to a maximum of 25us (30 readers). This is just + * a heuristic and is subjected to change in the future. + */ +static inline u64 rwsem_rspin_threshold(struct rw_semaphore *sem) +{ + long count = atomic_long_read(&sem->count); + int readers = count >> RWSEM_READER_SHIFT; + u64 delta; + + if (readers > 30) + readers = 30; + delta = (20 + readers) * NSEC_PER_USEC / 2; + + return sched_clock() + delta; +} + +static bool rwsem_optimistic_spin(struct rw_semaphore *sem, bool wlock) +{ + bool taken = false; + int prev_owner_state = OWNER_NULL; + int loop = 0; + u64 rspin_threshold = 0; + unsigned long nonspinnable = wlock ? RWSEM_WR_NONSPINNABLE + : RWSEM_RD_NONSPINNABLE; + + preempt_disable(); + + /* sem->wait_lock should not be held when doing optimistic spinning */ + if (!osq_lock(&sem->osq)) + goto done; + + /* + * Optimistically spin on the owner field and attempt to acquire the + * lock whenever the owner changes. Spinning will be stopped when: + * 1) the owning writer isn't running; or + * 2) readers own the lock and spinning time has exceeded limit. + */ + for (;;) { + enum owner_state owner_state; + + owner_state = rwsem_spin_on_owner(sem, nonspinnable); + if (!(owner_state & OWNER_SPINNABLE)) + break; + + /* + * Try to acquire the lock + */ + taken = wlock ? rwsem_try_write_lock_unqueued(sem) + : rwsem_try_read_lock_unqueued(sem); + + if (taken) + break; + + /* + * Time-based reader-owned rwsem optimistic spinning + */ + if (wlock && (owner_state == OWNER_READER)) { + /* + * Re-initialize rspin_threshold every time when + * the owner state changes from non-reader to reader. + * This allows a writer to steal the lock in between + * 2 reader phases and have the threshold reset at + * the beginning of the 2nd reader phase. + */ + if (prev_owner_state != OWNER_READER) { + if (rwsem_test_oflags(sem, nonspinnable)) + break; + rspin_threshold = rwsem_rspin_threshold(sem); + loop = 0; + } + + /* + * Check time threshold once every 16 iterations to + * avoid calling sched_clock() too frequently so + * as to reduce the average latency between the times + * when the lock becomes free and when the spinner + * is ready to do a trylock. + */ + else if (!(++loop & 0xf) && (sched_clock() > rspin_threshold)) { + rwsem_set_nonspinnable(sem); + lockevent_inc(rwsem_opt_nospin); + break; + } + } + + /* + * An RT task cannot do optimistic spinning if it cannot + * be sure the lock holder is running or live-lock may + * happen if the current task and the lock holder happen + * to run in the same CPU. However, aborting optimistic + * spinning while a NULL owner is detected may miss some + * opportunity where spinning can continue without causing + * problem. + * + * There are 2 possible cases where an RT task may be able + * to continue spinning. + * + * 1) The lock owner is in the process of releasing the + * lock, sem->owner is cleared but the lock has not + * been released yet. + * 2) The lock was free and owner cleared, but another + * task just comes in and acquire the lock before + * we try to get it. The new owner may be a spinnable + * writer. + * + * To take advantage of two scenarios listed agove, the RT + * task is made to retry one more time to see if it can + * acquire the lock or continue spinning on the new owning + * writer. Of course, if the time lag is long enough or the + * new owner is not a writer or spinnable, the RT task will + * quit spinning. + * + * If the owner is a writer, the need_resched() check is + * done inside rwsem_spin_on_owner(). If the owner is not + * a writer, need_resched() check needs to be done here. + */ + if (owner_state != OWNER_WRITER) { + if (need_resched()) + break; + if (rt_task(current) && + (prev_owner_state != OWNER_WRITER)) + break; + } + prev_owner_state = owner_state; + + /* + * The cpu_relax() call is a compiler barrier which forces + * everything in this loop to be re-loaded. We don't need + * memory barriers as we'll eventually observe the right + * values at the cost of a few extra spins. + */ + cpu_relax(); + } + osq_unlock(&sem->osq); +done: + preempt_enable(); + lockevent_cond_inc(rwsem_opt_fail, !taken); + return taken; +} + +/* + * Clear the owner's RWSEM_WR_NONSPINNABLE bit if it is set. This should + * only be called when the reader count reaches 0. + * + * This give writers better chance to acquire the rwsem first before + * readers when the rwsem was being held by readers for a relatively long + * period of time. Race can happen that an optimistic spinner may have + * just stolen the rwsem and set the owner, but just clearing the + * RWSEM_WR_NONSPINNABLE bit will do no harm anyway. + */ +static inline void clear_wr_nonspinnable(struct rw_semaphore *sem) +{ + if (rwsem_test_oflags(sem, RWSEM_WR_NONSPINNABLE)) + atomic_long_andnot(RWSEM_WR_NONSPINNABLE, &sem->owner); +} + +/* + * This function is called when the reader fails to acquire the lock via + * optimistic spinning. In this case we will still attempt to do a trylock + * when comparing the rwsem state right now with the state when entering + * the slowpath indicates that the reader is still in a valid reader phase. + * This happens when the following conditions are true: + * + * 1) The lock is currently reader owned, and + * 2) The lock is previously not reader-owned or the last read owner changes. + * + * In the former case, we have transitioned from a writer phase to a + * reader-phase while spinning. In the latter case, it means the reader + * phase hasn't ended when we entered the optimistic spinning loop. In + * both cases, the reader is eligible to acquire the lock. This is the + * secondary path where a read lock is acquired optimistically. + * + * The reader non-spinnable bit wasn't set at time of entry or it will + * not be here at all. + */ +static inline bool rwsem_reader_phase_trylock(struct rw_semaphore *sem, + unsigned long last_rowner) +{ + unsigned long owner = atomic_long_read(&sem->owner); + + if (!(owner & RWSEM_READER_OWNED)) + return false; + + if (((owner ^ last_rowner) & ~RWSEM_OWNER_FLAGS_MASK) && + rwsem_try_read_lock_unqueued(sem)) { + lockevent_inc(rwsem_opt_rlock2); + lockevent_add(rwsem_opt_fail, -1); + return true; + } + return false; +} +#else +static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem, + unsigned long nonspinnable) +{ + return false; +} + +static inline bool rwsem_optimistic_spin(struct rw_semaphore *sem, bool wlock) +{ + return false; +} + +static inline void clear_wr_nonspinnable(struct rw_semaphore *sem) { } + +static inline bool rwsem_reader_phase_trylock(struct rw_semaphore *sem, + unsigned long last_rowner) +{ + return false; +} +#endif + +/* + * Wait for the read lock to be granted + */ +static struct rw_semaphore __sched * +rwsem_down_read_slowpath(struct rw_semaphore *sem, int state) +{ + long count, adjustment = -RWSEM_READER_BIAS; + struct rwsem_waiter waiter; + DEFINE_WAKE_Q(wake_q); + bool wake = false; + + /* + * Save the current read-owner of rwsem, if available, and the + * reader nonspinnable bit. + */ + waiter.last_rowner = atomic_long_read(&sem->owner); + if (!(waiter.last_rowner & RWSEM_READER_OWNED)) + waiter.last_rowner &= RWSEM_RD_NONSPINNABLE; + + if (!rwsem_can_spin_on_owner(sem, RWSEM_RD_NONSPINNABLE)) + goto queue; + + /* + * Undo read bias from down_read() and do optimistic spinning. + */ + atomic_long_add(-RWSEM_READER_BIAS, &sem->count); + adjustment = 0; + if (rwsem_optimistic_spin(sem, false)) { + /* + * Wake up other readers in the wait list if the front + * waiter is a reader. + */ + if ((atomic_long_read(&sem->count) & RWSEM_FLAG_WAITERS)) { + raw_spin_lock_irq(&sem->wait_lock); + if (!list_empty(&sem->wait_list)) + rwsem_mark_wake(sem, RWSEM_WAKE_READ_OWNED, + &wake_q); + raw_spin_unlock_irq(&sem->wait_lock); + wake_up_q(&wake_q); + } + return sem; + } else if (rwsem_reader_phase_trylock(sem, waiter.last_rowner)) { + return sem; + } + +queue: + waiter.task = current; + waiter.type = RWSEM_WAITING_FOR_READ; + waiter.timeout = jiffies + RWSEM_WAIT_TIMEOUT; + + raw_spin_lock_irq(&sem->wait_lock); + if (list_empty(&sem->wait_list)) { + /* + * In case the wait queue is empty and the lock isn't owned + * by a writer or has the handoff bit set, this reader can + * exit the slowpath and return immediately as its + * RWSEM_READER_BIAS has already been set in the count. + */ + if (adjustment && !(atomic_long_read(&sem->count) & + (RWSEM_WRITER_MASK | RWSEM_FLAG_HANDOFF))) { + raw_spin_unlock_irq(&sem->wait_lock); + rwsem_set_reader_owned(sem); + lockevent_inc(rwsem_rlock_fast); + return sem; + } + adjustment += RWSEM_FLAG_WAITERS; + } + list_add_tail(&waiter.list, &sem->wait_list); + + /* we're now waiting on the lock, but no longer actively locking */ + if (adjustment) + count = atomic_long_add_return(adjustment, &sem->count); + else + count = atomic_long_read(&sem->count); + + /* + * If there are no active locks, wake the front queued process(es). + * + * If there are no writers and we are first in the queue, + * wake our own waiter to join the existing active readers ! + */ + if (!(count & RWSEM_LOCK_MASK)) { + clear_wr_nonspinnable(sem); + wake = true; + } + if (wake || (!(count & RWSEM_WRITER_MASK) && + (adjustment & RWSEM_FLAG_WAITERS))) + rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q); + + raw_spin_unlock_irq(&sem->wait_lock); + wake_up_q(&wake_q); + + /* wait to be given the lock */ + while (true) { + set_current_state(state); + if (!waiter.task) + break; + if (signal_pending_state(state, current)) { + raw_spin_lock_irq(&sem->wait_lock); + if (waiter.task) + goto out_nolock; + raw_spin_unlock_irq(&sem->wait_lock); + break; + } + schedule(); + lockevent_inc(rwsem_sleep_reader); + } + + __set_current_state(TASK_RUNNING); + lockevent_inc(rwsem_rlock); + return sem; +out_nolock: + list_del(&waiter.list); + if (list_empty(&sem->wait_list)) { + atomic_long_andnot(RWSEM_FLAG_WAITERS|RWSEM_FLAG_HANDOFF, + &sem->count); + } + raw_spin_unlock_irq(&sem->wait_lock); + __set_current_state(TASK_RUNNING); + lockevent_inc(rwsem_rlock_fail); + return ERR_PTR(-EINTR); +} + +/* + * This function is called by the a write lock owner. So the owner value + * won't get changed by others. + */ +static inline void rwsem_disable_reader_optspin(struct rw_semaphore *sem, + bool disable) +{ + if (unlikely(disable)) { + atomic_long_or(RWSEM_RD_NONSPINNABLE, &sem->owner); + lockevent_inc(rwsem_opt_norspin); + } +} + +/* + * Wait until we successfully acquire the write lock + */ +static struct rw_semaphore * +rwsem_down_write_slowpath(struct rw_semaphore *sem, int state) +{ + long count; + bool disable_rspin; + enum writer_wait_state wstate; + struct rwsem_waiter waiter; + struct rw_semaphore *ret = sem; + DEFINE_WAKE_Q(wake_q); + + /* do optimistic spinning and steal lock if possible */ + if (rwsem_can_spin_on_owner(sem, RWSEM_WR_NONSPINNABLE) && + rwsem_optimistic_spin(sem, true)) + return sem; + + /* + * Disable reader optimistic spinning for this rwsem after + * acquiring the write lock when the setting of the nonspinnable + * bits are observed. + */ + disable_rspin = atomic_long_read(&sem->owner) & RWSEM_NONSPINNABLE; + + /* + * Optimistic spinning failed, proceed to the slowpath + * and block until we can acquire the sem. + */ + waiter.task = current; + waiter.type = RWSEM_WAITING_FOR_WRITE; + waiter.timeout = jiffies + RWSEM_WAIT_TIMEOUT; + + raw_spin_lock_irq(&sem->wait_lock); + + /* account for this before adding a new element to the list */ + wstate = list_empty(&sem->wait_list) ? WRITER_FIRST : WRITER_NOT_FIRST; + + list_add_tail(&waiter.list, &sem->wait_list); + + /* we're now waiting on the lock */ + if (wstate == WRITER_NOT_FIRST) { + count = atomic_long_read(&sem->count); + + /* + * If there were already threads queued before us and: + * 1) there are no no active locks, wake the front + * queued process(es) as the handoff bit might be set. + * 2) there are no active writers and some readers, the lock + * must be read owned; so we try to wake any read lock + * waiters that were queued ahead of us. + */ + if (count & RWSEM_WRITER_MASK) + goto wait; + + rwsem_mark_wake(sem, (count & RWSEM_READER_MASK) + ? RWSEM_WAKE_READERS + : RWSEM_WAKE_ANY, &wake_q); + + if (!wake_q_empty(&wake_q)) { + /* + * We want to minimize wait_lock hold time especially + * when a large number of readers are to be woken up. + */ + raw_spin_unlock_irq(&sem->wait_lock); + wake_up_q(&wake_q); + wake_q_init(&wake_q); /* Used again, reinit */ + raw_spin_lock_irq(&sem->wait_lock); + } + } else { + atomic_long_or(RWSEM_FLAG_WAITERS, &sem->count); + } + +wait: + /* wait until we successfully acquire the lock */ + set_current_state(state); + while (true) { + if (rwsem_try_write_lock(sem, wstate)) + break; + + raw_spin_unlock_irq(&sem->wait_lock); + + /* Block until there are no active lockers. */ + for (;;) { + if (signal_pending_state(state, current)) + goto out_nolock; + + schedule(); + lockevent_inc(rwsem_sleep_writer); + set_current_state(state); + /* + * If HANDOFF bit is set, unconditionally do + * a trylock. + */ + if (wstate == WRITER_HANDOFF) + break; + + if ((wstate == WRITER_NOT_FIRST) && + (rwsem_first_waiter(sem) == &waiter)) + wstate = WRITER_FIRST; + + count = atomic_long_read(&sem->count); + if (!(count & RWSEM_LOCK_MASK)) + break; + + /* + * The setting of the handoff bit is deferred + * until rwsem_try_write_lock() is called. + */ + if ((wstate == WRITER_FIRST) && (rt_task(current) || + time_after(jiffies, waiter.timeout))) { + wstate = WRITER_HANDOFF; + lockevent_inc(rwsem_wlock_handoff); + break; + } + } + + raw_spin_lock_irq(&sem->wait_lock); + } + __set_current_state(TASK_RUNNING); + list_del(&waiter.list); + rwsem_disable_reader_optspin(sem, disable_rspin); + raw_spin_unlock_irq(&sem->wait_lock); + lockevent_inc(rwsem_wlock); + + return ret; + +out_nolock: + __set_current_state(TASK_RUNNING); + raw_spin_lock_irq(&sem->wait_lock); + list_del(&waiter.list); + + if (unlikely(wstate == WRITER_HANDOFF)) + atomic_long_add(-RWSEM_FLAG_HANDOFF, &sem->count); + + if (list_empty(&sem->wait_list)) + atomic_long_andnot(RWSEM_FLAG_WAITERS, &sem->count); + else + rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q); + raw_spin_unlock_irq(&sem->wait_lock); + wake_up_q(&wake_q); + lockevent_inc(rwsem_wlock_fail); + + return ERR_PTR(-EINTR); +} + +/* + * handle waking up a waiter on the semaphore + * - up_read/up_write has decremented the active part of count if we come here + */ +static struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem, long count) +{ + unsigned long flags; + DEFINE_WAKE_Q(wake_q); + + raw_spin_lock_irqsave(&sem->wait_lock, flags); + + if (!list_empty(&sem->wait_list)) + rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q); + + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); + wake_up_q(&wake_q); + + return sem; +} + +/* + * downgrade a write lock into a read lock + * - caller incremented waiting part of count and discovered it still negative + * - just wake up any readers at the front of the queue + */ +static struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem) +{ + unsigned long flags; + DEFINE_WAKE_Q(wake_q); + + raw_spin_lock_irqsave(&sem->wait_lock, flags); + + if (!list_empty(&sem->wait_list)) + rwsem_mark_wake(sem, RWSEM_WAKE_READ_OWNED, &wake_q); + + raw_spin_unlock_irqrestore(&sem->wait_lock, flags); + wake_up_q(&wake_q); + + return sem; +} + +/* + * lock for reading + */ +inline void __down_read(struct rw_semaphore *sem) +{ + if (!rwsem_read_trylock(sem)) { + rwsem_down_read_slowpath(sem, TASK_UNINTERRUPTIBLE); + DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem); + } else { + rwsem_set_reader_owned(sem); + } +} + +static inline int __down_read_killable(struct rw_semaphore *sem) +{ + if (!rwsem_read_trylock(sem)) { + if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_KILLABLE))) + return -EINTR; + DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem); + } else { + rwsem_set_reader_owned(sem); + } + return 0; +} + +static inline int __down_read_trylock(struct rw_semaphore *sem) +{ + /* + * Optimize for the case when the rwsem is not locked at all. + */ + long tmp = RWSEM_UNLOCKED_VALUE; + + do { + if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp, + tmp + RWSEM_READER_BIAS)) { + rwsem_set_reader_owned(sem); + return 1; + } + } while (!(tmp & RWSEM_READ_FAILED_MASK)); + return 0; +} + +/* + * lock for writing + */ +static inline void __down_write(struct rw_semaphore *sem) +{ + long tmp = RWSEM_UNLOCKED_VALUE; + + if (unlikely(!atomic_long_try_cmpxchg_acquire(&sem->count, &tmp, + RWSEM_WRITER_LOCKED))) + rwsem_down_write_slowpath(sem, TASK_UNINTERRUPTIBLE); + else + rwsem_set_owner(sem); +} + +static inline int __down_write_killable(struct rw_semaphore *sem) +{ + long tmp = RWSEM_UNLOCKED_VALUE; + + if (unlikely(!atomic_long_try_cmpxchg_acquire(&sem->count, &tmp, + RWSEM_WRITER_LOCKED))) { + if (IS_ERR(rwsem_down_write_slowpath(sem, TASK_KILLABLE))) + return -EINTR; + } else { + rwsem_set_owner(sem); + } + return 0; +} + +static inline int __down_write_trylock(struct rw_semaphore *sem) +{ + long tmp = RWSEM_UNLOCKED_VALUE; + + if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp, + RWSEM_WRITER_LOCKED)) { + rwsem_set_owner(sem); + return true; + } + return false; +} + +/* + * unlock after reading + */ +inline void __up_read(struct rw_semaphore *sem) +{ + long tmp; + + DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem); + rwsem_clear_reader_owned(sem); + tmp = atomic_long_add_return_release(-RWSEM_READER_BIAS, &sem->count); + DEBUG_RWSEMS_WARN_ON(tmp < 0, sem); + if (unlikely((tmp & (RWSEM_LOCK_MASK|RWSEM_FLAG_WAITERS)) == + RWSEM_FLAG_WAITERS)) { + clear_wr_nonspinnable(sem); + rwsem_wake(sem, tmp); + } +} + +/* + * unlock after writing + */ +static inline void __up_write(struct rw_semaphore *sem) +{ + long tmp; + + /* + * sem->owner may differ from current if the ownership is transferred + * to an anonymous writer by setting the RWSEM_NONSPINNABLE bits. + */ + DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && + !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE), sem); + rwsem_clear_owner(sem); + tmp = atomic_long_fetch_add_release(-RWSEM_WRITER_LOCKED, &sem->count); + if (unlikely(tmp & RWSEM_FLAG_WAITERS)) + rwsem_wake(sem, tmp); +} + +/* + * downgrade write lock to read lock + */ +static inline void __downgrade_write(struct rw_semaphore *sem) +{ + long tmp; + + /* + * When downgrading from exclusive to shared ownership, + * anything inside the write-locked region cannot leak + * into the read side. In contrast, anything in the + * read-locked region is ok to be re-ordered into the + * write side. As such, rely on RELEASE semantics. + */ + DEBUG_RWSEMS_WARN_ON(rwsem_owner(sem) != current, sem); + tmp = atomic_long_fetch_add_release( + -RWSEM_WRITER_LOCKED+RWSEM_READER_BIAS, &sem->count); + rwsem_set_reader_owned(sem); + if (tmp & RWSEM_FLAG_WAITERS) + rwsem_downgrade_wake(sem); +} /* * lock for reading @@ -25,7 +1446,6 @@ void __sched down_read(struct rw_semaphore *sem) LOCK_CONTENDED(sem, __down_read_trylock, __down_read); } - EXPORT_SYMBOL(down_read); int __sched down_read_killable(struct rw_semaphore *sem) @@ -40,7 +1460,6 @@ int __sched down_read_killable(struct rw_semaphore *sem) return 0; } - EXPORT_SYMBOL(down_read_killable); /* @@ -54,7 +1473,6 @@ int down_read_trylock(struct rw_semaphore *sem) rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_); return ret; } - EXPORT_SYMBOL(down_read_trylock); /* @@ -64,10 +1482,8 @@ void __sched down_write(struct rw_semaphore *sem) { might_sleep(); rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_); - LOCK_CONTENDED(sem, __down_write_trylock, __down_write); } - EXPORT_SYMBOL(down_write); /* @@ -78,14 +1494,14 @@ int __sched down_write_killable(struct rw_semaphore *sem) might_sleep(); rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_); - if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock, __down_write_killable)) { + if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock, + __down_write_killable)) { rwsem_release(&sem->dep_map, 1, _RET_IP_); return -EINTR; } return 0; } - EXPORT_SYMBOL(down_write_killable); /* @@ -100,7 +1516,6 @@ int down_write_trylock(struct rw_semaphore *sem) return ret; } - EXPORT_SYMBOL(down_write_trylock); /* @@ -109,10 +1524,8 @@ EXPORT_SYMBOL(down_write_trylock); void up_read(struct rw_semaphore *sem) { rwsem_release(&sem->dep_map, 1, _RET_IP_); - __up_read(sem); } - EXPORT_SYMBOL(up_read); /* @@ -121,10 +1534,8 @@ EXPORT_SYMBOL(up_read); void up_write(struct rw_semaphore *sem) { rwsem_release(&sem->dep_map, 1, _RET_IP_); - __up_write(sem); } - EXPORT_SYMBOL(up_write); /* @@ -133,10 +1544,8 @@ EXPORT_SYMBOL(up_write); void downgrade_write(struct rw_semaphore *sem) { lock_downgrade(&sem->dep_map, _RET_IP_); - __downgrade_write(sem); } - EXPORT_SYMBOL(downgrade_write); #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -145,40 +1554,32 @@ void down_read_nested(struct rw_semaphore *sem, int subclass) { might_sleep(); rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_); - LOCK_CONTENDED(sem, __down_read_trylock, __down_read); } - EXPORT_SYMBOL(down_read_nested); void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest) { might_sleep(); rwsem_acquire_nest(&sem->dep_map, 0, 0, nest, _RET_IP_); - LOCK_CONTENDED(sem, __down_write_trylock, __down_write); } - EXPORT_SYMBOL(_down_write_nest_lock); void down_read_non_owner(struct rw_semaphore *sem) { might_sleep(); - __down_read(sem); __rwsem_set_reader_owned(sem, NULL); } - EXPORT_SYMBOL(down_read_non_owner); void down_write_nested(struct rw_semaphore *sem, int subclass) { might_sleep(); rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_); - LOCK_CONTENDED(sem, __down_write_trylock, __down_write); } - EXPORT_SYMBOL(down_write_nested); int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass) @@ -186,23 +1587,21 @@ int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass) might_sleep(); rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_); - if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock, __down_write_killable)) { + if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock, + __down_write_killable)) { rwsem_release(&sem->dep_map, 1, _RET_IP_); return -EINTR; } return 0; } - EXPORT_SYMBOL(down_write_killable_nested); void up_read_non_owner(struct rw_semaphore *sem) { - DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner & RWSEM_READER_OWNED), - sem); + DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem); __up_read(sem); } - EXPORT_SYMBOL(up_read_non_owner); #endif diff --git a/kernel/locking/rwsem.h b/kernel/locking/rwsem.h index 64877f5294e3..2534ce49f648 100644 --- a/kernel/locking/rwsem.h +++ b/kernel/locking/rwsem.h @@ -1,304 +1,10 @@ /* SPDX-License-Identifier: GPL-2.0 */ -/* - * The least significant 2 bits of the owner value has the following - * meanings when set. - * - RWSEM_READER_OWNED (bit 0): The rwsem is owned by readers - * - RWSEM_ANONYMOUSLY_OWNED (bit 1): The rwsem is anonymously owned, - * i.e. the owner(s) cannot be readily determined. It can be reader - * owned or the owning writer is indeterminate. - * - * When a writer acquires a rwsem, it puts its task_struct pointer - * into the owner field. It is cleared after an unlock. - * - * When a reader acquires a rwsem, it will also puts its task_struct - * pointer into the owner field with both the RWSEM_READER_OWNED and - * RWSEM_ANONYMOUSLY_OWNED bits set. On unlock, the owner field will - * largely be left untouched. So for a free or reader-owned rwsem, - * the owner value may contain information about the last reader that - * acquires the rwsem. The anonymous bit is set because that particular - * reader may or may not still own the lock. - * - * That information may be helpful in debugging cases where the system - * seems to hang on a reader owned rwsem especially if only one reader - * is involved. Ideally we would like to track all the readers that own - * a rwsem, but the overhead is simply too big. - */ -#include "lock_events.h" -#define RWSEM_READER_OWNED (1UL << 0) -#define RWSEM_ANONYMOUSLY_OWNED (1UL << 1) +#ifndef __INTERNAL_RWSEM_H +#define __INTERNAL_RWSEM_H +#include <linux/rwsem.h> -#ifdef CONFIG_DEBUG_RWSEMS -# define DEBUG_RWSEMS_WARN_ON(c, sem) do { \ - if (!debug_locks_silent && \ - WARN_ONCE(c, "DEBUG_RWSEMS_WARN_ON(%s): count = 0x%lx, owner = 0x%lx, curr 0x%lx, list %sempty\n",\ - #c, atomic_long_read(&(sem)->count), \ - (long)((sem)->owner), (long)current, \ - list_empty(&(sem)->wait_list) ? "" : "not ")) \ - debug_locks_off(); \ - } while (0) -#else -# define DEBUG_RWSEMS_WARN_ON(c, sem) -#endif +extern void __down_read(struct rw_semaphore *sem); +extern void __up_read(struct rw_semaphore *sem); -/* - * R/W semaphores originally for PPC using the stuff in lib/rwsem.c. - * Adapted largely from include/asm-i386/rwsem.h - * by Paul Mackerras <paulus@samba.org>. - */ - -/* - * the semaphore definition - */ -#ifdef CONFIG_64BIT -# define RWSEM_ACTIVE_MASK 0xffffffffL -#else -# define RWSEM_ACTIVE_MASK 0x0000ffffL -#endif - -#define RWSEM_ACTIVE_BIAS 0x00000001L -#define RWSEM_WAITING_BIAS (-RWSEM_ACTIVE_MASK-1) -#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) - -#ifdef CONFIG_RWSEM_SPIN_ON_OWNER -/* - * All writes to owner are protected by WRITE_ONCE() to make sure that - * store tearing can't happen as optimistic spinners may read and use - * the owner value concurrently without lock. Read from owner, however, - * may not need READ_ONCE() as long as the pointer value is only used - * for comparison and isn't being dereferenced. - */ -static inline void rwsem_set_owner(struct rw_semaphore *sem) -{ - WRITE_ONCE(sem->owner, current); -} - -static inline void rwsem_clear_owner(struct rw_semaphore *sem) -{ - WRITE_ONCE(sem->owner, NULL); -} - -/* - * The task_struct pointer of the last owning reader will be left in - * the owner field. - * - * Note that the owner value just indicates the task has owned the rwsem - * previously, it may not be the real owner or one of the real owners - * anymore when that field is examined, so take it with a grain of salt. - */ -static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem, - struct task_struct *owner) -{ - unsigned long val = (unsigned long)owner | RWSEM_READER_OWNED - | RWSEM_ANONYMOUSLY_OWNED; - - WRITE_ONCE(sem->owner, (struct task_struct *)val); -} - -static inline void rwsem_set_reader_owned(struct rw_semaphore *sem) -{ - __rwsem_set_reader_owned(sem, current); -} - -/* - * Return true if the a rwsem waiter can spin on the rwsem's owner - * and steal the lock, i.e. the lock is not anonymously owned. - * N.B. !owner is considered spinnable. - */ -static inline bool is_rwsem_owner_spinnable(struct task_struct *owner) -{ - return !((unsigned long)owner & RWSEM_ANONYMOUSLY_OWNED); -} - -/* - * Return true if rwsem is owned by an anonymous writer or readers. - */ -static inline bool rwsem_has_anonymous_owner(struct task_struct *owner) -{ - return (unsigned long)owner & RWSEM_ANONYMOUSLY_OWNED; -} - -#ifdef CONFIG_DEBUG_RWSEMS -/* - * With CONFIG_DEBUG_RWSEMS configured, it will make sure that if there - * is a task pointer in owner of a reader-owned rwsem, it will be the - * real owner or one of the real owners. The only exception is when the - * unlock is done by up_read_non_owner(). - */ -#define rwsem_clear_reader_owned rwsem_clear_reader_owned -static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem) -{ - unsigned long val = (unsigned long)current | RWSEM_READER_OWNED - | RWSEM_ANONYMOUSLY_OWNED; - if (READ_ONCE(sem->owner) == (struct task_struct *)val) - cmpxchg_relaxed((unsigned long *)&sem->owner, val, - RWSEM_READER_OWNED | RWSEM_ANONYMOUSLY_OWNED); -} -#endif - -#else -static inline void rwsem_set_owner(struct rw_semaphore *sem) -{ -} - -static inline void rwsem_clear_owner(struct rw_semaphore *sem) -{ -} - -static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem, - struct task_struct *owner) -{ -} - -static inline void rwsem_set_reader_owned(struct rw_semaphore *sem) -{ -} -#endif - -#ifndef rwsem_clear_reader_owned -static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem) -{ -} -#endif - -extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem); -extern struct rw_semaphore *rwsem_down_read_failed_killable(struct rw_semaphore *sem); -extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem); -extern struct rw_semaphore *rwsem_down_write_failed_killable(struct rw_semaphore *sem); -extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem); -extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem); - -/* - * lock for reading - */ -static inline void __down_read(struct rw_semaphore *sem) -{ - if (unlikely(atomic_long_inc_return_acquire(&sem->count) <= 0)) { - rwsem_down_read_failed(sem); - DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner & - RWSEM_READER_OWNED), sem); - } else { - rwsem_set_reader_owned(sem); - } -} - -static inline int __down_read_killable(struct rw_semaphore *sem) -{ - if (unlikely(atomic_long_inc_return_acquire(&sem->count) <= 0)) { - if (IS_ERR(rwsem_down_read_failed_killable(sem))) - return -EINTR; - DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner & - RWSEM_READER_OWNED), sem); - } else { - rwsem_set_reader_owned(sem); - } - return 0; -} - -static inline int __down_read_trylock(struct rw_semaphore *sem) -{ - /* - * Optimize for the case when the rwsem is not locked at all. - */ - long tmp = RWSEM_UNLOCKED_VALUE; - - lockevent_inc(rwsem_rtrylock); - do { - if (atomic_long_try_cmpxchg_acquire(&sem->count, &tmp, - tmp + RWSEM_ACTIVE_READ_BIAS)) { - rwsem_set_reader_owned(sem); - return 1; - } - } while (tmp >= 0); - return 0; -} - -/* - * lock for writing - */ -static inline void __down_write(struct rw_semaphore *sem) -{ - long tmp; - - tmp = atomic_long_add_return_acquire(RWSEM_ACTIVE_WRITE_BIAS, - &sem->count); - if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS)) - rwsem_down_write_failed(sem); - rwsem_set_owner(sem); -} - -static inline int __down_write_killable(struct rw_semaphore *sem) -{ - long tmp; - - tmp = atomic_long_add_return_acquire(RWSEM_ACTIVE_WRITE_BIAS, - &sem->count); - if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS)) - if (IS_ERR(rwsem_down_write_failed_killable(sem))) - return -EINTR; - rwsem_set_owner(sem); - return 0; -} - -static inline int __down_write_trylock(struct rw_semaphore *sem) -{ - long tmp; - - lockevent_inc(rwsem_wtrylock); - tmp = atomic_long_cmpxchg_acquire(&sem->count, RWSEM_UNLOCKED_VALUE, - RWSEM_ACTIVE_WRITE_BIAS); - if (tmp == RWSEM_UNLOCKED_VALUE) { - rwsem_set_owner(sem); - return true; - } - return false; -} - -/* - * unlock after reading - */ -static inline void __up_read(struct rw_semaphore *sem) -{ - long tmp; - - DEBUG_RWSEMS_WARN_ON(!((unsigned long)sem->owner & RWSEM_READER_OWNED), - sem); - rwsem_clear_reader_owned(sem); - tmp = atomic_long_dec_return_release(&sem->count); - if (unlikely(tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)) - rwsem_wake(sem); -} - -/* - * unlock after writing - */ -static inline void __up_write(struct rw_semaphore *sem) -{ - DEBUG_RWSEMS_WARN_ON(sem->owner != current, sem); - rwsem_clear_owner(sem); - if (unlikely(atomic_long_sub_return_release(RWSEM_ACTIVE_WRITE_BIAS, - &sem->count) < 0)) - rwsem_wake(sem); -} - -/* - * downgrade write lock to read lock - */ -static inline void __downgrade_write(struct rw_semaphore *sem) -{ - long tmp; - - /* - * When downgrading from exclusive to shared ownership, - * anything inside the write-locked region cannot leak - * into the read side. In contrast, anything in the - * read-locked region is ok to be re-ordered into the - * write side. As such, rely on RELEASE semantics. - */ - DEBUG_RWSEMS_WARN_ON(sem->owner != current, sem); - tmp = atomic_long_add_return_release(-RWSEM_WAITING_BIAS, &sem->count); - rwsem_set_reader_owned(sem); - if (tmp < 0) - rwsem_downgrade_wake(sem); -} +#endif /* __INTERNAL_RWSEM_H */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f35930f5e528..8591529e1753 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6189,6 +6189,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t u64 time, cost; s64 delta; int cpu, nr = INT_MAX; + int this = smp_processor_id(); this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc)); if (!this_sd) @@ -6212,7 +6213,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t nr = 4; } - time = local_clock(); + time = cpu_clock(this); for_each_cpu_wrap(cpu, sched_domain_span(sd), target) { if (!--nr) @@ -6223,7 +6224,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t break; } - time = local_clock() - time; + time = cpu_clock(this) - time; cost = this_sd->avg_scan_cost; delta = (s64)(time - cost) / 8; this_sd->avg_scan_cost += delta; diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 6629cab453e8..06d9c9d70385 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1095,7 +1095,7 @@ config PROVE_LOCKING select DEBUG_SPINLOCK select DEBUG_MUTEXES select DEBUG_RT_MUTEXES if RT_MUTEXES - select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER + select DEBUG_RWSEMS select DEBUG_WW_MUTEX_SLOWPATH select DEBUG_LOCK_ALLOC select TRACE_IRQFLAGS @@ -1199,10 +1199,10 @@ config DEBUG_WW_MUTEX_SLOWPATH config DEBUG_RWSEMS bool "RW Semaphore debugging: basic checks" - depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER + depends on DEBUG_KERNEL help - This debugging feature allows mismatched rw semaphore locks and unlocks - to be detected and reported. + This debugging feature allows mismatched rw semaphore locks + and unlocks to be detected and reported. config DEBUG_LOCK_ALLOC bool "Lock debugging: detect incorrect freeing of live locks" diff --git a/lib/atomic64.c b/lib/atomic64.c index 7e6905751522..e98c85a99787 100644 --- a/lib/atomic64.c +++ b/lib/atomic64.c @@ -42,11 +42,11 @@ static inline raw_spinlock_t *lock_addr(const atomic64_t *v) return &atomic64_lock[addr & (NR_LOCKS - 1)].lock; } -long long atomic64_read(const atomic64_t *v) +s64 atomic64_read(const atomic64_t *v) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); - long long val; + s64 val; raw_spin_lock_irqsave(lock, flags); val = v->counter; @@ -55,7 +55,7 @@ long long atomic64_read(const atomic64_t *v) } EXPORT_SYMBOL(atomic64_read); -void atomic64_set(atomic64_t *v, long long i) +void atomic64_set(atomic64_t *v, s64 i) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); @@ -67,7 +67,7 @@ void atomic64_set(atomic64_t *v, long long i) EXPORT_SYMBOL(atomic64_set); #define ATOMIC64_OP(op, c_op) \ -void atomic64_##op(long long a, atomic64_t *v) \ +void atomic64_##op(s64 a, atomic64_t *v) \ { \ unsigned long flags; \ raw_spinlock_t *lock = lock_addr(v); \ @@ -79,11 +79,11 @@ void atomic64_##op(long long a, atomic64_t *v) \ EXPORT_SYMBOL(atomic64_##op); #define ATOMIC64_OP_RETURN(op, c_op) \ -long long atomic64_##op##_return(long long a, atomic64_t *v) \ +s64 atomic64_##op##_return(s64 a, atomic64_t *v) \ { \ unsigned long flags; \ raw_spinlock_t *lock = lock_addr(v); \ - long long val; \ + s64 val; \ \ raw_spin_lock_irqsave(lock, flags); \ val = (v->counter c_op a); \ @@ -93,11 +93,11 @@ long long atomic64_##op##_return(long long a, atomic64_t *v) \ EXPORT_SYMBOL(atomic64_##op##_return); #define ATOMIC64_FETCH_OP(op, c_op) \ -long long atomic64_fetch_##op(long long a, atomic64_t *v) \ +s64 atomic64_fetch_##op(s64 a, atomic64_t *v) \ { \ unsigned long flags; \ raw_spinlock_t *lock = lock_addr(v); \ - long long val; \ + s64 val; \ \ raw_spin_lock_irqsave(lock, flags); \ val = v->counter; \ @@ -130,11 +130,11 @@ ATOMIC64_OPS(xor, ^=) #undef ATOMIC64_OP_RETURN #undef ATOMIC64_OP -long long atomic64_dec_if_positive(atomic64_t *v) +s64 atomic64_dec_if_positive(atomic64_t *v) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); - long long val; + s64 val; raw_spin_lock_irqsave(lock, flags); val = v->counter - 1; @@ -145,11 +145,11 @@ long long atomic64_dec_if_positive(atomic64_t *v) } EXPORT_SYMBOL(atomic64_dec_if_positive); -long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n) +s64 atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); - long long val; + s64 val; raw_spin_lock_irqsave(lock, flags); val = v->counter; @@ -160,11 +160,11 @@ long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n) } EXPORT_SYMBOL(atomic64_cmpxchg); -long long atomic64_xchg(atomic64_t *v, long long new) +s64 atomic64_xchg(atomic64_t *v, s64 new) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); - long long val; + s64 val; raw_spin_lock_irqsave(lock, flags); val = v->counter; @@ -174,11 +174,11 @@ long long atomic64_xchg(atomic64_t *v, long long new) } EXPORT_SYMBOL(atomic64_xchg); -long long atomic64_fetch_add_unless(atomic64_t *v, long long a, long long u) +s64 atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u) { unsigned long flags; raw_spinlock_t *lock = lock_addr(v); - long long val; + s64 val; raw_spin_lock_irqsave(lock, flags); val = v->counter; diff --git a/scripts/atomic/check-atomics.sh b/scripts/atomic/check-atomics.sh index cfa0c2f71c84..8378c63a1e09 100755 --- a/scripts/atomic/check-atomics.sh +++ b/scripts/atomic/check-atomics.sh @@ -22,7 +22,7 @@ while read header; do OLDSUM="$(tail -n 1 ${LINUXDIR}/include/${header})" OLDSUM="${OLDSUM#// }" - NEWSUM="$(head -n -1 ${LINUXDIR}/include/${header} | sha1sum)" + NEWSUM="$(sed '$d' ${LINUXDIR}/include/${header} | sha1sum)" NEWSUM="${NEWSUM%% *}" if [ "${OLDSUM}" != "${NEWSUM}" ]; then diff --git a/security/apparmor/label.c b/security/apparmor/label.c index 068e93c5d29c..59f1cc2557a7 100644 --- a/security/apparmor/label.c +++ b/security/apparmor/label.c @@ -76,7 +76,7 @@ void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new) AA_BUG(!orig); AA_BUG(!new); - lockdep_assert_held_exclusive(&labels_set(orig)->lock); + lockdep_assert_held_write(&labels_set(orig)->lock); tmp = rcu_dereference_protected(orig->proxy->label, &labels_ns(orig)->lock); @@ -566,7 +566,7 @@ static bool __label_remove(struct aa_label *label, struct aa_label *new) AA_BUG(!ls); AA_BUG(!label); - lockdep_assert_held_exclusive(&ls->lock); + lockdep_assert_held_write(&ls->lock); if (new) __aa_proxy_redirect(label, new); @@ -603,7 +603,7 @@ static bool __label_replace(struct aa_label *old, struct aa_label *new) AA_BUG(!ls); AA_BUG(!old); AA_BUG(!new); - lockdep_assert_held_exclusive(&ls->lock); + lockdep_assert_held_write(&ls->lock); AA_BUG(new->flags & FLAG_IN_TREE); if (!label_is_stale(old)) @@ -640,7 +640,7 @@ static struct aa_label *__label_insert(struct aa_labelset *ls, AA_BUG(!ls); AA_BUG(!label); AA_BUG(labels_set(label) != ls); - lockdep_assert_held_exclusive(&ls->lock); + lockdep_assert_held_write(&ls->lock); AA_BUG(label->flags & FLAG_IN_TREE); /* Figure out where to put new node */ |