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Commit 74846d35 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

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: default avatarPeter 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: default avatarIngo Molnar <mingo@elte.hu>
parent 3c44780b

arch/x86/kernel/cpu/perf_event_intel.c

+16 −2
Original line number Diff line number Diff line
@@ -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)

arch/x86/kernel/cpu/perf_event_intel_lbr.c

+3 −0
Original line number Diff line number Diff line
@@ -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