Commit-ID:  e5ea9b54a055619160bbfe527ebb7d7191823d66
Gitweb:     https://git.kernel.org/tip/e5ea9b54a055619160bbfe527ebb7d7191823d66
Author:     Dan Carpenter <[email protected]>
AuthorDate: Sat, 17 Mar 2018 14:52:16 +0300
Committer:  Ingo Molnar <[email protected]>
CommitDate: Tue, 20 Mar 2018 08:53:31 +0100

perf/x86/intel: Don't accidentally clear high bits in bdw_limit_period()

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 <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vince Weaver <[email protected]>
Fixes: 294fe0f52a44 ("perf/x86/intel: Add INST_RETIRED.ALL workarounds")
Link: http://lkml.kernel.org/r/20180317115216.GB4035@mwanda
Signed-off-by: Ingo Molnar <[email protected]>
---
 arch/x86/events/intel/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 56457cb73448..9b18a227fff7 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3194,7 +3194,7 @@ static unsigned bdw_limit_period(struct perf_event 
*event, unsigned left)
                        X86_CONFIG(.event=0xc0, .umask=0x01)) {
                if (left < 128)
                        left = 128;
-               left &= ~0x3fu;
+               left &= ~0x3fULL;
        }
        return left;
 }

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