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authorLinus Torvalds <torvalds@linux-foundation.org>2020-04-07 12:30:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-04-07 12:30:41 -0700
commitf9db97d751870cbffc85f4aa0d8aca8a79432691 (patch)
tree486315ccf50ea5c5c85a5c67d1bfdd80db5d60f9 /arch
parent12782fbe0f77dcc36c48de8b0ab36d336620a3e7 (diff)
parent106c90922e1e0cd5fcbb34be8ebbb3e8a8e71909 (diff)
downloadlinux-f9db97d751870cbffc85f4aa0d8aca8a79432691.tar.bz2
Merge branch 'parisc-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull parisc updates from Helge Deller: "Some cleanups in arch_rw locking functions, improved interrupt handling in arch spinlocks, coversions to request_irq() and syscall table generation cleanups" * 'parisc-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: remove nargs from __SYSCALL parisc: Refactor alternative code to accept multiple conditions parisc: Rework arch_rw locking functions parisc: Improve interrupt handling in arch_spin_lock_flags() parisc: Replace setup_irq() by request_irq()
Diffstat (limited to 'arch')
-rw-r--r--arch/parisc/include/asm/spinlock.h160
-rw-r--r--arch/parisc/include/asm/spinlock_types.h14
-rw-r--r--arch/parisc/kernel/alternative.c37
-rw-r--r--arch/parisc/kernel/irq.c22
-rw-r--r--arch/parisc/kernel/syscall.S2
-rw-r--r--arch/parisc/kernel/syscalls/syscalltbl.sh4
6 files changed, 112 insertions, 127 deletions
diff --git a/arch/parisc/include/asm/spinlock.h b/arch/parisc/include/asm/spinlock.h
index 197d2247e4db..70fecb8dc4e2 100644
--- a/arch/parisc/include/asm/spinlock.h
+++ b/arch/parisc/include/asm/spinlock.h
@@ -10,25 +10,34 @@
static inline int arch_spin_is_locked(arch_spinlock_t *x)
{
volatile unsigned int *a = __ldcw_align(x);
+ smp_mb();
return *a == 0;
}
-#define arch_spin_lock(lock) arch_spin_lock_flags(lock, 0)
+static inline void arch_spin_lock(arch_spinlock_t *x)
+{
+ volatile unsigned int *a;
+
+ a = __ldcw_align(x);
+ while (__ldcw(a) == 0)
+ while (*a == 0)
+ cpu_relax();
+}
static inline void arch_spin_lock_flags(arch_spinlock_t *x,
unsigned long flags)
{
volatile unsigned int *a;
+ unsigned long flags_dis;
a = __ldcw_align(x);
- while (__ldcw(a) == 0)
+ while (__ldcw(a) == 0) {
+ local_save_flags(flags_dis);
+ local_irq_restore(flags);
while (*a == 0)
- if (flags & PSW_SM_I) {
- local_irq_enable();
- cpu_relax();
- local_irq_disable();
- } else
- cpu_relax();
+ cpu_relax();
+ local_irq_restore(flags_dis);
+ }
}
#define arch_spin_lock_flags arch_spin_lock_flags
@@ -58,116 +67,93 @@ static inline int arch_spin_trylock(arch_spinlock_t *x)
/*
* Read-write spinlocks, allowing multiple readers but only one writer.
- * Linux rwlocks are unfair to writers; they can be starved for an indefinite
- * time by readers. With care, they can also be taken in interrupt context.
+ * Unfair locking as Writers could be starved indefinitely by Reader(s)
*
- * In the PA-RISC implementation, we have a spinlock and a counter.
- * Readers use the lock to serialise their access to the counter (which
- * records how many readers currently hold the lock).
- * Writers hold the spinlock, preventing any readers or other writers from
- * grabbing the rwlock.
+ * The spinlock itself is contained in @counter and access to it is
+ * serialized with @lock_mutex.
*/
-/* Note that we have to ensure interrupts are disabled in case we're
- * interrupted by some other code that wants to grab the same read lock */
-static __inline__ void arch_read_lock(arch_rwlock_t *rw)
+/* 1 - lock taken successfully */
+static inline int arch_read_trylock(arch_rwlock_t *rw)
{
+ int ret = 0;
unsigned long flags;
- local_irq_save(flags);
- arch_spin_lock_flags(&rw->lock, flags);
- rw->counter++;
- arch_spin_unlock(&rw->lock);
- local_irq_restore(flags);
-}
-/* Note that we have to ensure interrupts are disabled in case we're
- * interrupted by some other code that wants to grab the same read lock */
-static __inline__ void arch_read_unlock(arch_rwlock_t *rw)
-{
- unsigned long flags;
local_irq_save(flags);
- arch_spin_lock_flags(&rw->lock, flags);
- rw->counter--;
- arch_spin_unlock(&rw->lock);
+ arch_spin_lock(&(rw->lock_mutex));
+
+ /*
+ * zero means writer holds the lock exclusively, deny Reader.
+ * Otherwise grant lock to first/subseq reader
+ */
+ if (rw->counter > 0) {
+ rw->counter--;
+ ret = 1;
+ }
+
+ arch_spin_unlock(&(rw->lock_mutex));
local_irq_restore(flags);
+
+ return ret;
}
-/* Note that we have to ensure interrupts are disabled in case we're
- * interrupted by some other code that wants to grab the same read lock */
-static __inline__ int arch_read_trylock(arch_rwlock_t *rw)
+/* 1 - lock taken successfully */
+static inline int arch_write_trylock(arch_rwlock_t *rw)
{
+ int ret = 0;
unsigned long flags;
- retry:
+
local_irq_save(flags);
- if (arch_spin_trylock(&rw->lock)) {
- rw->counter++;
- arch_spin_unlock(&rw->lock);
- local_irq_restore(flags);
- return 1;
+ arch_spin_lock(&(rw->lock_mutex));
+
+ /*
+ * If reader(s) hold lock (lock < __ARCH_RW_LOCK_UNLOCKED__),
+ * deny writer. Otherwise if unlocked grant to writer
+ * Hence the claim that Linux rwlocks are unfair to writers.
+ * (can be starved for an indefinite time by readers).
+ */
+ if (rw->counter == __ARCH_RW_LOCK_UNLOCKED__) {
+ rw->counter = 0;
+ ret = 1;
}
-
+ arch_spin_unlock(&(rw->lock_mutex));
local_irq_restore(flags);
- /* If write-locked, we fail to acquire the lock */
- if (rw->counter < 0)
- return 0;
- /* Wait until we have a realistic chance at the lock */
- while (arch_spin_is_locked(&rw->lock) && rw->counter >= 0)
+ return ret;
+}
+
+static inline void arch_read_lock(arch_rwlock_t *rw)
+{
+ while (!arch_read_trylock(rw))
cpu_relax();
+}
- goto retry;
+static inline void arch_write_lock(arch_rwlock_t *rw)
+{
+ while (!arch_write_trylock(rw))
+ cpu_relax();
}
-/* Note that we have to ensure interrupts are disabled in case we're
- * interrupted by some other code that wants to read_trylock() this lock */
-static __inline__ void arch_write_lock(arch_rwlock_t *rw)
+static inline void arch_read_unlock(arch_rwlock_t *rw)
{
unsigned long flags;
-retry:
- local_irq_save(flags);
- arch_spin_lock_flags(&rw->lock, flags);
- if (rw->counter != 0) {
- arch_spin_unlock(&rw->lock);
- local_irq_restore(flags);
-
- while (rw->counter != 0)
- cpu_relax();
-
- goto retry;
- }
-
- rw->counter = -1; /* mark as write-locked */
- mb();
+ local_irq_save(flags);
+ arch_spin_lock(&(rw->lock_mutex));
+ rw->counter++;
+ arch_spin_unlock(&(rw->lock_mutex));
local_irq_restore(flags);
}
-static __inline__ void arch_write_unlock(arch_rwlock_t *rw)
-{
- rw->counter = 0;
- arch_spin_unlock(&rw->lock);
-}
-
-/* Note that we have to ensure interrupts are disabled in case we're
- * interrupted by some other code that wants to read_trylock() this lock */
-static __inline__ int arch_write_trylock(arch_rwlock_t *rw)
+static inline void arch_write_unlock(arch_rwlock_t *rw)
{
unsigned long flags;
- int result = 0;
local_irq_save(flags);
- if (arch_spin_trylock(&rw->lock)) {
- if (rw->counter == 0) {
- rw->counter = -1;
- result = 1;
- } else {
- /* Read-locked. Oh well. */
- arch_spin_unlock(&rw->lock);
- }
- }
+ arch_spin_lock(&(rw->lock_mutex));
+ rw->counter = __ARCH_RW_LOCK_UNLOCKED__;
+ arch_spin_unlock(&(rw->lock_mutex));
local_irq_restore(flags);
-
- return result;
}
#endif /* __ASM_SPINLOCK_H */
diff --git a/arch/parisc/include/asm/spinlock_types.h b/arch/parisc/include/asm/spinlock_types.h
index 42979c5704dc..ca39ee350c3f 100644
--- a/arch/parisc/include/asm/spinlock_types.h
+++ b/arch/parisc/include/asm/spinlock_types.h
@@ -12,11 +12,19 @@ typedef struct {
#endif
} arch_spinlock_t;
+
+/* counter:
+ * Unlocked : 0x0100_0000
+ * Read lock(s) : 0x00FF_FFFF to 0x01 (Multiple Readers decrement it)
+ * Write lock : 0x0, but only if prior value is "unlocked" 0x0100_0000
+ */
typedef struct {
- arch_spinlock_t lock;
- volatile int counter;
+ arch_spinlock_t lock_mutex;
+ volatile unsigned int counter;
} arch_rwlock_t;
-#define __ARCH_RW_LOCK_UNLOCKED { __ARCH_SPIN_LOCK_UNLOCKED, 0 }
+#define __ARCH_RW_LOCK_UNLOCKED__ 0x01000000
+#define __ARCH_RW_LOCK_UNLOCKED { .lock_mutex = __ARCH_SPIN_LOCK_UNLOCKED, \
+ .counter = __ARCH_RW_LOCK_UNLOCKED__ }
#endif
diff --git a/arch/parisc/kernel/alternative.c b/arch/parisc/kernel/alternative.c
index 3c66d5c4d90d..fa28c4c9f972 100644
--- a/arch/parisc/kernel/alternative.c
+++ b/arch/parisc/kernel/alternative.c
@@ -25,6 +25,22 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
struct alt_instr *entry;
int index = 0, applied = 0;
int num_cpus = num_online_cpus();
+ u32 cond_check;
+
+ cond_check = ALT_COND_ALWAYS |
+ ((num_cpus == 1) ? ALT_COND_NO_SMP : 0) |
+ ((cache_info.dc_size == 0) ? ALT_COND_NO_DCACHE : 0) |
+ ((cache_info.ic_size == 0) ? ALT_COND_NO_ICACHE : 0) |
+ (running_on_qemu ? ALT_COND_RUN_ON_QEMU : 0) |
+ ((split_tlb == 0) ? ALT_COND_NO_SPLIT_TLB : 0) |
+ /*
+ * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit
+ * set (bit #61, big endian), we have to flush and sync every
+ * time IO-PDIR is changed in Ike/Astro.
+ */
+ (((boot_cpu_data.cpu_type > pcxw_) &&
+ ((boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC) == 0))
+ ? ALT_COND_NO_IOC_FDC : 0);
for (entry = start; entry < end; entry++, index++) {
@@ -38,29 +54,14 @@ void __init_or_module apply_alternatives(struct alt_instr *start,
WARN_ON(!cond);
- if (cond != ALT_COND_ALWAYS && no_alternatives)
+ if ((cond & ALT_COND_ALWAYS) == 0 && no_alternatives)
continue;
pr_debug("Check %d: Cond 0x%x, Replace %02d instructions @ 0x%px with 0x%08x\n",
index, cond, len, from, replacement);
- if ((cond & ALT_COND_NO_SMP) && (num_cpus != 1))
- continue;
- if ((cond & ALT_COND_NO_DCACHE) && (cache_info.dc_size != 0))
- continue;
- if ((cond & ALT_COND_NO_ICACHE) && (cache_info.ic_size != 0))
- continue;
- if ((cond & ALT_COND_RUN_ON_QEMU) && !running_on_qemu)
- continue;
-
- /*
- * If the PDC_MODEL capabilities has Non-coherent IO-PDIR bit
- * set (bit #61, big endian), we have to flush and sync every
- * time IO-PDIR is changed in Ike/Astro.
- */
- if ((cond & ALT_COND_NO_IOC_FDC) &&
- ((boot_cpu_data.cpu_type <= pcxw_) ||
- (boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC)))
+ /* Bounce out if none of the conditions are true. */
+ if ((cond & cond_check) == 0)
continue;
/* Want to replace pdtlb by a pdtlb,l instruction? */
diff --git a/arch/parisc/kernel/irq.c b/arch/parisc/kernel/irq.c
index e5fcfb70cc7c..e76c86619949 100644
--- a/arch/parisc/kernel/irq.c
+++ b/arch/parisc/kernel/irq.c
@@ -560,33 +560,23 @@ void do_cpu_irq_mask(struct pt_regs *regs)
goto out;
}
-static struct irqaction timer_action = {
- .handler = timer_interrupt,
- .name = "timer",
- .flags = IRQF_TIMER | IRQF_PERCPU | IRQF_IRQPOLL,
-};
-
-#ifdef CONFIG_SMP
-static struct irqaction ipi_action = {
- .handler = ipi_interrupt,
- .name = "IPI",
- .flags = IRQF_PERCPU,
-};
-#endif
-
static void claim_cpu_irqs(void)
{
+ unsigned long flags = IRQF_TIMER | IRQF_PERCPU | IRQF_IRQPOLL;
int i;
+
for (i = CPU_IRQ_BASE; i <= CPU_IRQ_MAX; i++) {
irq_set_chip_and_handler(i, &cpu_interrupt_type,
handle_percpu_irq);
}
irq_set_handler(TIMER_IRQ, handle_percpu_irq);
- setup_irq(TIMER_IRQ, &timer_action);
+ if (request_irq(TIMER_IRQ, timer_interrupt, flags, "timer", NULL))
+ pr_err("Failed to register timer interrupt\n");
#ifdef CONFIG_SMP
irq_set_handler(IPI_IRQ, handle_percpu_irq);
- setup_irq(IPI_IRQ, &ipi_action);
+ if (request_irq(IPI_IRQ, ipi_interrupt, IRQF_PERCPU, "IPI", NULL))
+ pr_err("Failed to register IPI interrupt\n");
#endif
}
diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
index 97ac707c6bff..f05c9d5b6b9e 100644
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -935,7 +935,7 @@ ENTRY(lws_table)
END(lws_table)
/* End of lws table */
-#define __SYSCALL(nr, entry, nargs) ASM_ULONG_INSN entry
+#define __SYSCALL(nr, entry) ASM_ULONG_INSN entry
.align 8
ENTRY(sys_call_table)
.export sys_call_table,data
diff --git a/arch/parisc/kernel/syscalls/syscalltbl.sh b/arch/parisc/kernel/syscalls/syscalltbl.sh
index 45b5bae26240..f7393a7b18aa 100644
--- a/arch/parisc/kernel/syscalls/syscalltbl.sh
+++ b/arch/parisc/kernel/syscalls/syscalltbl.sh
@@ -13,10 +13,10 @@ emit() {
t_entry="$3"
while [ $t_nxt -lt $t_nr ]; do
- printf "__SYSCALL(%s, sys_ni_syscall, )\n" "${t_nxt}"
+ printf "__SYSCALL(%s,sys_ni_syscall)\n" "${t_nxt}"
t_nxt=$((t_nxt+1))
done
- printf "__SYSCALL(%s, %s, )\n" "${t_nxt}" "${t_entry}"
+ printf "__SYSCALL(%s,%s)\n" "${t_nxt}" "${t_entry}"
}
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