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-rw-r--r--arch/x86/events/core.c18
-rw-r--r--arch/x86/include/asm/mmu_context.h4
2 files changed, 15 insertions, 7 deletions
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 6e3f0c18908e..9a89d98c55bd 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -49,6 +49,7 @@ DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = {
.enabled = 1,
};
+DEFINE_STATIC_KEY_FALSE(rdpmc_never_available_key);
DEFINE_STATIC_KEY_FALSE(rdpmc_always_available_key);
u64 __read_mostly hw_cache_event_ids
@@ -2181,21 +2182,26 @@ static ssize_t set_attr_rdpmc(struct device *cdev,
if (x86_pmu.attr_rdpmc_broken)
return -ENOTSUPP;
- if ((val == 2) != (x86_pmu.attr_rdpmc == 2)) {
+ if (val != x86_pmu.attr_rdpmc) {
/*
- * Changing into or out of always available, aka
- * perf-event-bypassing mode. This path is extremely slow,
+ * Changing into or out of never available or always available,
+ * aka perf-event-bypassing mode. This path is extremely slow,
* but only root can trigger it, so it's okay.
*/
+ if (val == 0)
+ static_branch_inc(&rdpmc_never_available_key);
+ else if (x86_pmu.attr_rdpmc == 0)
+ static_branch_dec(&rdpmc_never_available_key);
+
if (val == 2)
static_branch_inc(&rdpmc_always_available_key);
- else
+ else if (x86_pmu.attr_rdpmc == 2)
static_branch_dec(&rdpmc_always_available_key);
+
on_each_cpu(refresh_pce, NULL, 1);
+ x86_pmu.attr_rdpmc = val;
}
- x86_pmu.attr_rdpmc = val;
-
return count;
}
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 16ae821483c8..5f33924e200f 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -26,12 +26,14 @@ static inline void paravirt_activate_mm(struct mm_struct *prev,
#ifdef CONFIG_PERF_EVENTS
+DECLARE_STATIC_KEY_FALSE(rdpmc_never_available_key);
DECLARE_STATIC_KEY_FALSE(rdpmc_always_available_key);
static inline void load_mm_cr4_irqsoff(struct mm_struct *mm)
{
if (static_branch_unlikely(&rdpmc_always_available_key) ||
- atomic_read(&mm->context.perf_rdpmc_allowed))
+ (!static_branch_unlikely(&rdpmc_never_available_key) &&
+ atomic_read(&mm->context.perf_rdpmc_allowed)))
cr4_set_bits_irqsoff(X86_CR4_PCE);
else
cr4_clear_bits_irqsoff(X86_CR4_PCE);