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arch/x86/kernel/cpu/perf_event_msr.c: use sign_extend64() for sign extension

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Signed-off-by: Martin Kepplinger <martin.kepplinger@theobroma-systems.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: George Spelvin <linux@horizon.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Maxime Coquelin <maxime.coquelin@st.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Martin Kepplinger 2015-11-06 16:31:08 -08:00 committed by Linus Torvalds
parent 06d8f8178c
commit 78e3c79510
1 changed files with 3 additions and 4 deletions
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arch/x86/kernel/cpu/perf_event_msr.c
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@ -163,10 +163,9 @@ static void msr_event_update(struct perf_event *event)
goto again;
delta = now - prev;
if (unlikely(event->hw.event_base == MSR_SMI_COUNT)) {
delta <<= 32;
delta >>= 32; /* sign extend */
}
if (unlikely(event->hw.event_base == MSR_SMI_COUNT))
delta = sign_extend64(delta, 31);
local64_add(now - prev, &event->count);
}