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| author | Will Deacon <will.deacon@arm.com> | 2010-12-02 18:01:49 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-12-04 11:18:08 +0000 |
| commit | 961ec6daa7b14f376c30d447a830fa4783a2112c (patch) | |
| tree | fd4952bd65fa9e991de7687eaef4b2e5af7a0e70 /arch/arm/kernel/perf_event_xscale.c | |
| parent | 4d6b7a779be34e1df296abc1dc555134a8cf34af (diff) | |
| download | blackbird-op-linux-961ec6daa7b14f376c30d447a830fa4783a2112c.tar.gz blackbird-op-linux-961ec6daa7b14f376c30d447a830fa4783a2112c.zip | |
ARM: 6521/1: perf: use raw_spinlock_t for pmu_lock
For kernels built with PREEMPT_RT, critical sections protected
by standard spinlocks are preemptible. This is not acceptable
on perf as (a) we may be scheduled onto a different CPU whilst
reading/writing banked PMU registers and (b) the latency when
reading the PMU registers becomes unpredictable.
This patch upgrades the pmu_lock spinlock to a raw_spinlock
instead.
Reported-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/perf_event_xscale.c')
| -rw-r--r-- | arch/arm/kernel/perf_event_xscale.c | 32 |
1 files changed, 16 insertions, 16 deletions
diff --git a/arch/arm/kernel/perf_event_xscale.c b/arch/arm/kernel/perf_event_xscale.c index f14fbb6c345b..28cd3b025bc3 100644 --- a/arch/arm/kernel/perf_event_xscale.c +++ b/arch/arm/kernel/perf_event_xscale.c @@ -291,12 +291,12 @@ xscale1pmu_enable_event(struct hw_perf_event *hwc, int idx) return; } - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); val = xscale1pmu_read_pmnc(); val &= ~mask; val |= evt; xscale1pmu_write_pmnc(val); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static void @@ -322,12 +322,12 @@ xscale1pmu_disable_event(struct hw_perf_event *hwc, int idx) return; } - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); val = xscale1pmu_read_pmnc(); val &= ~mask; val |= evt; xscale1pmu_write_pmnc(val); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static int @@ -355,11 +355,11 @@ xscale1pmu_start(void) { unsigned long flags, val; - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); val = xscale1pmu_read_pmnc(); val |= XSCALE_PMU_ENABLE; xscale1pmu_write_pmnc(val); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static void @@ -367,11 +367,11 @@ xscale1pmu_stop(void) { unsigned long flags, val; - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); val = xscale1pmu_read_pmnc(); val &= ~XSCALE_PMU_ENABLE; xscale1pmu_write_pmnc(val); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static inline u32 @@ -635,10 +635,10 @@ xscale2pmu_enable_event(struct hw_perf_event *hwc, int idx) return; } - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); xscale2pmu_write_event_select(evtsel); xscale2pmu_write_int_enable(ien); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static void @@ -678,10 +678,10 @@ xscale2pmu_disable_event(struct hw_perf_event *hwc, int idx) return; } - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); xscale2pmu_write_event_select(evtsel); xscale2pmu_write_int_enable(ien); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static int @@ -705,11 +705,11 @@ xscale2pmu_start(void) { unsigned long flags, val; - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); val = xscale2pmu_read_pmnc() & ~XSCALE_PMU_CNT64; val |= XSCALE_PMU_ENABLE; xscale2pmu_write_pmnc(val); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static void @@ -717,11 +717,11 @@ xscale2pmu_stop(void) { unsigned long flags, val; - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); val = xscale2pmu_read_pmnc(); val &= ~XSCALE_PMU_ENABLE; xscale2pmu_write_pmnc(val); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static inline u32 |
