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Subject[tip:perf/core] perf/x86/intel/uncore: Correct fixed counter index check in generic code
Commit-ID:  4749f8196452eeb73cf2086a6a9705bae479d33d
Gitweb: https://git.kernel.org/tip/4749f8196452eeb73cf2086a6a9705bae479d33d
Author: Kan Liang <kan.liang@intel.com>
AuthorDate: Thu, 3 May 2018 11:25:08 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 31 May 2018 12:36:28 +0200

perf/x86/intel/uncore: Correct fixed counter index check in generic code

There is no index which is bigger than UNCORE_PMC_IDX_FIXED. The only
exception is client IMC uncore, which has been specially handled.
For generic code, it is not correct to use >= to check fixed counter.
The code quality issue will bring problem when a new counter index is
introduced.

Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: acme@kernel.org
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1525371913-10597-3-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/events/intel/uncore.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index a7956fc7ca1d..3b0f93eb3cc0 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -218,7 +218,7 @@ void uncore_perf_event_update(struct intel_uncore_box *box, struct perf_event *e
u64 prev_count, new_count, delta;
int shift;

- if (event->hw.idx >= UNCORE_PMC_IDX_FIXED)
+ if (event->hw.idx == UNCORE_PMC_IDX_FIXED)
shift = 64 - uncore_fixed_ctr_bits(box);
else
shift = 64 - uncore_perf_ctr_bits(box);
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