[PATCH 3.18 15/85] perf/x86/intel/uncore: Correct fixed counter index check for NHM

Greg Kroah-Hartman
2018-08-07T18:56:40Z

From: Kan Liang <kan.liang@intel.com>

[ Upstream commit d71f11c076c420c4e2fceb4faefa144e055e0935 ]

For Nehalem and Westmere, there is only one fixed counter for W-Box.
There is no index which is bigger than UNCORE_PMC_IDX_FIXED.
It is not correct to use >= to check fixed counter.
The code quality issue will bring problem when 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/1525371913-10597-2-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_nhmex.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/cpu/perf_event_intel_uncore_nhmex.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore_nhmex.c
@@ -240,7 +240,7 @@ static void nhmex_uncore_msr_enable_even
{
struct hw_perf_event *hwc = &event->hw;

- if (hwc->idx >= UNCORE_PMC_IDX_FIXED)
+ if (hwc->idx == UNCORE_PMC_IDX_FIXED)
wrmsrl(hwc->config_base, NHMEX_PMON_CTL_EN_BIT0);
else if (box->pmu->type->event_mask & NHMEX_PMON_CTL_EN_BIT0)
wrmsrl(hwc->config_base, hwc->config | NHMEX_PMON_CTL_EN_BIT22);