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

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: 21d59e3e2c40 ("perf/x86/amd/core: Detect PerfMonV2 support")
Reported-by: Mario Limonciello <[email protected]>
Signed-off-by: Sandipan Das <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: https://lore.kernel.org/r/550a026764342cf7e5812680e3e2b91fe662b5ac.1706526029.git.sandipan.das@amd.com

diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index 69a3b02e50bb0cfbe2688769ad3a5ea72fd8e11f..aec16e581f5b2aad520bcdfbab7bff61ca99c072 100644 (file)
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -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;