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Commit 4fd4a210 authored by Sandipan Das's avatar Sandipan Das Committed by Sasha Levin
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perf/x86/amd/core: Avoid register reset when CPU is dead



[ Upstream commit ad8c9128 ]

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: 21d59e3e ("perf/x86/amd/core: Detect PerfMonV2 support")
Reported-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Signed-off-by: default avatarSandipan Das <sandipan.das@amd.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/550a026764342cf7e5812680e3e2b91fe662b5ac.1706526029.git.sandipan.das@amd.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 889846df
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