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perf/x86/msr: Fix SMI overflow

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We compute 'delta' and properly sign extend it and then ignore it and
recompute the raw value, loosing the sign extention.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: kan.liang@intel.com
Cc: linux-kernel@vger.kernel.org
Cc: luto@kernel.org
Cc: ray.huang@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2016-05-10 14:16:54 +02:00 committed by Ingo Molnar
parent ec336c879c
commit 3c3116b745
1 changed files with 1 additions and 1 deletions
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arch/x86/events/msr.c
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@ -166,7 +166,7 @@ static void msr_event_update(struct perf_event *event)
if (unlikely(event->hw.event_base == MSR_SMI_COUNT))
delta = sign_extend64(delta, 31);
local64_add(now - prev, &event->count);
local64_add(delta, &event->count);
}
static void msr_event_start(struct perf_event *event, int flags)