Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 024/124] perf/x86/intel/uncore: Correct fixed counter index check in generic code | Date | Sat, 4 Aug 2018 11:00:13 +0200 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Kan Liang <kan.liang@intel.com>
[ Upstream commit 4749f8196452eeb73cf2086a6a9705bae479d33d ]
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> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/x86/kernel/cpu/perf_event_intel_uncore.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c @@ -229,7 +229,7 @@ void uncore_perf_event_update(struct int 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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