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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-30 11:43:50 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-30 11:43:50 -0700 |
commit | b69bea8a657b681442765b06be92a2607b1bd875 (patch) | |
tree | 8dcecaf4e5eff737500b73d402b4ef81c1b5368c /drivers | |
parent | 3edd8db2d53fe6c96ad66248bb1479ae62807268 (diff) | |
parent | eb1f00237aca2e368b93db79303f8433d1976d10 (diff) | |
download | linux-b69bea8a657b681442765b06be92a2607b1bd875.tar.bz2 |
Merge tag 'locking-urgent-2020-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Thomas Gleixner:
"A set of fixes for lockdep, tracing and RCU:
- Prevent recursion by using raw_cpu_* operations
- Fixup the interrupt state in the cpu idle code to be consistent
- Push rcu_idle_enter/exit() invocations deeper into the idle path so
that the lock operations are inside the RCU watching sections
- Move trace_cpu_idle() into generic code so it's called before RCU
goes idle.
- Handle raw_local_irq* vs. local_irq* operations correctly
- Move the tracepoints out from under the lockdep recursion handling
which turned out to be fragile and inconsistent"
* tag 'locking-urgent-2020-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
lockdep,trace: Expose tracepoints
lockdep: Only trace IRQ edges
mips: Implement arch_irqs_disabled()
arm64: Implement arch_irqs_disabled()
nds32: Implement arch_irqs_disabled()
locking/lockdep: Cleanup
x86/entry: Remove unused THUNKs
cpuidle: Move trace_cpu_idle() into generic code
cpuidle: Make CPUIDLE_FLAG_TLB_FLUSHED generic
sched,idle,rcu: Push rcu_idle deeper into the idle path
cpuidle: Fixup IRQ state
lockdep: Use raw_cpu_*() for per-cpu variables
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/cpuidle/cpuidle.c | 19 | ||||
-rw-r--r-- | drivers/idle/intel_idle.c | 16 |
2 files changed, 14 insertions, 21 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 87197319ab06..04becd70cc41 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -22,6 +22,7 @@ #include <linux/module.h> #include <linux/suspend.h> #include <linux/tick.h> +#include <linux/mmu_context.h> #include <trace/events/power.h> #include "cpuidle.h" @@ -145,21 +146,24 @@ static void enter_s2idle_proper(struct cpuidle_driver *drv, * executing it contains RCU usage regarded as invalid in the idle * context, so tell RCU about that. */ - RCU_NONIDLE(tick_freeze()); + tick_freeze(); /* * The state used here cannot be a "coupled" one, because the "coupled" * cpuidle mechanism enables interrupts and doing that with timekeeping * suspended is generally unsafe. */ stop_critical_timings(); + rcu_idle_enter(); drv->states[index].enter_s2idle(dev, drv, index); - WARN_ON(!irqs_disabled()); + if (WARN_ON_ONCE(!irqs_disabled())) + local_irq_disable(); /* * timekeeping_resume() that will be called by tick_unfreeze() for the * first CPU executing it calls functions containing RCU read-side * critical sections, so tell RCU about that. */ - RCU_NONIDLE(tick_unfreeze()); + rcu_idle_exit(); + tick_unfreeze(); start_critical_timings(); time_end = ns_to_ktime(local_clock()); @@ -225,19 +229,24 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, broadcast = false; } + if (target_state->flags & CPUIDLE_FLAG_TLB_FLUSHED) + leave_mm(dev->cpu); + /* Take note of the planned idle state. */ sched_idle_set_state(target_state); - trace_cpu_idle_rcuidle(index, dev->cpu); + trace_cpu_idle(index, dev->cpu); time_start = ns_to_ktime(local_clock()); stop_critical_timings(); + rcu_idle_enter(); entered_state = target_state->enter(dev, drv, index); + rcu_idle_exit(); start_critical_timings(); sched_clock_idle_wakeup_event(); time_end = ns_to_ktime(local_clock()); - trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu); + trace_cpu_idle(PWR_EVENT_EXIT, dev->cpu); /* The cpu is no longer idle or about to enter idle. */ sched_idle_set_state(NULL); diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 8e0fb1a5bdbd..9a810e4a7946 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -90,14 +90,6 @@ static unsigned int mwait_substates __initdata; #define CPUIDLE_FLAG_ALWAYS_ENABLE BIT(15) /* - * Set this flag for states where the HW flushes the TLB for us - * and so we don't need cross-calls to keep it consistent. - * If this flag is set, SW flushes the TLB, so even if the - * HW doesn't do the flushing, this flag is safe to use. - */ -#define CPUIDLE_FLAG_TLB_FLUSHED BIT(16) - -/* * MWAIT takes an 8-bit "hint" in EAX "suggesting" * the C-state (top nibble) and sub-state (bottom nibble) * 0x00 means "MWAIT(C1)", 0x10 means "MWAIT(C2)" etc. @@ -131,14 +123,6 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev, unsigned long eax = flg2MWAIT(state->flags); unsigned long ecx = 1; /* break on interrupt flag */ bool tick; - int cpu = smp_processor_id(); - - /* - * leave_mm() to avoid costly and often unnecessary wakeups - * for flushing the user TLB's associated with the active mm. - */ - if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED) - leave_mm(cpu); if (!static_cpu_has(X86_FEATURE_ARAT)) { /* |