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[v2,3/3] perf/x86/amd/core: Avoid register reset when CPU is dead

Message ID 69e89600fe5ebb2d4e870d1bb7f1ac6d7954d259.1704103399.git.sandipan.das@amd.com
State New
Headers
Series perf/x86/amd: Miscellaneous fixes |

Commit Message

Sandipan Das Jan. 2, 2024, 6:01 a.m. UTC 
  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.

Link: https://lore.kernel.org/all/20231026170330.4657-3-mario.limonciello@amd.com/
Reported-by: Mario Limonciello <mario.limonciello@amd.com>
Fixes: 21d59e3e2c40 ("perf/x86/amd/core: Detect PerfMonV2 support")
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
---
 arch/x86/events/amd/core.c | 1 -
 1 file changed, 1 deletion(-)
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Patch

diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index ffdfaee08b08..63514c311f44 100644
--- 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;