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perf/x86/amd/core: Avoid register reset when CPU is dead

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When bringing a CPU online, some of the PMC and LBR related registers
are reset. The same is done when a CPU is taken offline although that
is unnecessary. This currently happens in the "cpu_dead" callback which
is also incorrect as the callback runs on a control CPU instead of the
one that is being taken offline. This also affects hibernation and
suspend to RAM on some platforms as reported in the link below.

Fixes: 21d59e3e2c ("perf/x86/amd/core: Detect PerfMonV2 support")
Reported-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/550a026764342cf7e5812680e3e2b91fe662b5ac.1706526029.git.sandipan.das@amd.com
This commit is contained in:
Sandipan Das 2024-01-29 16:36:26 +05:30 • committed by Ingo Molnar
parent 29297ffffb
commit ad8c91282c
1 changed files with 0 additions and 1 deletions
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arch/x86/events/amd/core.c
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@ -604,7 +604,6 @@ static void amd_pmu_cpu_dead(int cpu)
kfree(cpuhw->lbr_sel);
cpuhw->lbr_sel = NULL;
amd_pmu_cpu_reset(cpu);
if (!x86_pmu.amd_nb_constraints)
return;