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Subject[PATCH 4.9 56/67] perf/x86/intel: Dont accidentally clear high bits in bdw_limit_period()
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@oracle.com>

commit e5ea9b54a055619160bbfe527ebb7d7191823d66 upstream.

We intended to clear the lowest 6 bits but because of a type bug we
clear the high 32 bits as well. Andi says that periods are rarely more
than U32_MAX so this bug probably doesn't have a huge runtime impact.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 294fe0f52a44 ("perf/x86/intel: Add INST_RETIRED.ALL workarounds")
Link: http://lkml.kernel.org/r/20180317115216.GB4035@mwanda
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/events/intel/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3025,7 +3025,7 @@ static unsigned bdw_limit_period(struct
X86_CONFIG(.event=0xc0, .umask=0x01)) {
if (left < 128)
left = 128;
- left &= ~0x3fu;
+ left &= ~0x3fULL;
}
return left;
}

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