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    Subject[PATCH 4.4 024/124] perf/x86/intel/uncore: Correct fixed counter index check in generic code
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

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

    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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