From 961ec6daa7b14f376c30d447a830fa4783a2112c Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 2 Dec 2010 18:01:49 +0100 Subject: [PATCH] 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 Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/kernel/perf_event.c | 2 +- arch/arm/kernel/perf_event_v6.c | 20 +++++++++--------- arch/arm/kernel/perf_event_v7.c | 16 +++++++-------- arch/arm/kernel/perf_event_xscale.c | 32 ++++++++++++++--------------- 4 files changed, 35 insertions(+), 35 deletions(-) diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index 50c197bfac0f..624e2a5de2b3 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -32,7 +32,7 @@ static struct platform_device *pmu_device; * Hardware lock to serialize accesses to PMU registers. Needed for the * read/modify/write sequences. */ -static DEFINE_SPINLOCK(pmu_lock); +static DEFINE_RAW_SPINLOCK(pmu_lock); /* * ARMv6 supports a maximum of 3 events, starting from index 1. If we add diff --git a/arch/arm/kernel/perf_event_v6.c b/arch/arm/kernel/perf_event_v6.c index 3f427aae211d..c058bfc8532b 100644 --- a/arch/arm/kernel/perf_event_v6.c +++ b/arch/arm/kernel/perf_event_v6.c @@ -426,12 +426,12 @@ armv6pmu_enable_event(struct hw_perf_event *hwc, * Mask out the current event and set the counter to count the event * that we're interested in. */ - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); val = armv6_pmcr_read(); val &= ~mask; val |= evt; armv6_pmcr_write(val); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static irqreturn_t @@ -500,11 +500,11 @@ armv6pmu_start(void) { unsigned long flags, val; - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); val = armv6_pmcr_read(); val |= ARMV6_PMCR_ENABLE; armv6_pmcr_write(val); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static void @@ -512,11 +512,11 @@ armv6pmu_stop(void) { unsigned long flags, val; - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); val = armv6_pmcr_read(); val &= ~ARMV6_PMCR_ENABLE; armv6_pmcr_write(val); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static int @@ -570,12 +570,12 @@ armv6pmu_disable_event(struct hw_perf_event *hwc, * of ETM bus signal assertion cycles. The external reporting should * be disabled and so this should never increment. */ - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); val = armv6_pmcr_read(); val &= ~mask; val |= evt; armv6_pmcr_write(val); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static void @@ -599,12 +599,12 @@ armv6mpcore_pmu_disable_event(struct hw_perf_event *hwc, * Unlike UP ARMv6, we don't have a way of stopping the counters. We * simply disable the interrupt reporting. */ - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); val = armv6_pmcr_read(); val &= ~mask; val |= evt; armv6_pmcr_write(val); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static const struct arm_pmu armv6pmu = { diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c index a68ff1c10dec..2e1402556fa0 100644 --- a/arch/arm/kernel/perf_event_v7.c +++ b/arch/arm/kernel/perf_event_v7.c @@ -689,7 +689,7 @@ static void armv7pmu_enable_event(struct hw_perf_event *hwc, int idx) * Enable counter and interrupt, and set the counter to count * the event that we're interested in. */ - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); /* * Disable counter @@ -713,7 +713,7 @@ static void armv7pmu_enable_event(struct hw_perf_event *hwc, int idx) */ armv7_pmnc_enable_counter(idx); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static void armv7pmu_disable_event(struct hw_perf_event *hwc, int idx) @@ -723,7 +723,7 @@ static void armv7pmu_disable_event(struct hw_perf_event *hwc, int idx) /* * Disable counter and interrupt */ - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); /* * Disable counter @@ -735,7 +735,7 @@ static void armv7pmu_disable_event(struct hw_perf_event *hwc, int idx) */ armv7_pmnc_disable_intens(idx); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev) @@ -805,20 +805,20 @@ static void armv7pmu_start(void) { unsigned long flags; - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); /* Enable all counters */ armv7_pmnc_write(armv7_pmnc_read() | ARMV7_PMNC_E); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static void armv7pmu_stop(void) { unsigned long flags; - spin_lock_irqsave(&pmu_lock, flags); + raw_spin_lock_irqsave(&pmu_lock, flags); /* Disable all counters */ armv7_pmnc_write(armv7_pmnc_read() & ~ARMV7_PMNC_E); - spin_unlock_irqrestore(&pmu_lock, flags); + raw_spin_unlock_irqrestore(&pmu_lock, flags); } static int armv7pmu_get_event_idx(struct cpu_hw_events *cpuc, 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 -- 2.39.2