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perf, x86: Clear the LBRs on init 

Some CPUs have errata where the LBR is not cleared on Power-On. So always
clear the LBRs before use.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: paulus@samba.org
Cc: eranian@google.com
Cc: robert.richter@amd.com
Cc: fweisbec@gmail.com
LKML-Reference: <20100305154128.966563424@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
hifive-unleashed-5.1
Peter Zijlstra 2010-03-05 13:49:35 +01:00 committed by Ingo Molnar
parent 3c44780b22
commit 74846d35b2
2 changed files with 19 additions and 2 deletions
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18
arch/x86/kernel/cpu/perf_event_intel.c
View File

@ -767,6 +767,20 @@ static __initconst struct x86_pmu core_pmu = {
.event_constraints = intel_core_event_constraints,
};
static void intel_pmu_cpu_starting(int cpu)
{
init_debug_store_on_cpu(cpu);
/*
* Deal with CPUs that don't clear their LBRs on power-up.
*/
intel_pmu_lbr_reset();
}
static void intel_pmu_cpu_dying(int cpu)
{
fini_debug_store_on_cpu(cpu);
}
static __initconst struct x86_pmu intel_pmu = {
.name = "Intel",
.handle_irq = intel_pmu_handle_irq,
@ -788,8 +802,8 @@ static __initconst struct x86_pmu intel_pmu = {
.max_period = (1ULL << 31) - 1,
.get_event_constraints = intel_get_event_constraints,
.cpu_starting = init_debug_store_on_cpu,
.cpu_dying = fini_debug_store_on_cpu,
.cpu_starting = intel_pmu_cpu_starting,
.cpu_dying = intel_pmu_cpu_dying,
};
static void intel_clovertown_quirks(void)

3
arch/x86/kernel/cpu/perf_event_intel_lbr.c
View File

@ -53,6 +53,9 @@ static void intel_pmu_lbr_reset_64(void)
static void intel_pmu_lbr_reset(void)
{
if (!x86_pmu.lbr_nr)
return;
if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_32)
intel_pmu_lbr_reset_32();
else