perf/x86/amd: Add idle hooks for branch sampling
authorStephane Eranian <eranian@google.com>
Tue, 22 Mar 2022 22:15:13 +0000 (15:15 -0700)
committerPeter Zijlstra <peterz@infradead.org>
Tue, 5 Apr 2022 08:24:38 +0000 (10:24 +0200)
commitd5616bac7adadbf42a3b63b8717e75eb82a2cc2c
treede075a68f6b4b1265a8ecd0f0cf1bf65e08d084e
parent2a606a18cd672a16343d146a126721b34cc6adbd
perf/x86/amd: Add idle hooks for branch sampling

On AMD Fam19h Zen3, the branch sampling (BRS) feature must be disabled before
entering low power and re-enabled (if was active) when returning from low
power. Otherwise, the NMI interrupt may be held up for too long and cause
problems. Stopping BRS will cause the NMI to be delivered if it was held up.

Define a perf_amd_brs_lopwr_cb() callback to stop/restart BRS.  The callback
is protected by a jump label which is enabled only when AMD BRS is detected.
In all other cases, the callback is never called.

Signed-off-by: Stephane Eranian <eranian@google.com>
[peterz: static_call() and build fixes]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220322221517.2510440-10-eranian@google.com
arch/x86/events/amd/brs.c
arch/x86/events/amd/core.c
arch/x86/events/perf_event.h
arch/x86/include/asm/perf_event.h