linux-kernel - [PATCH V4 2/8] perf/x86/intel/uncore: correct fixed counter index check for NHM

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Date:   Thu,  2 Nov 2017 13:29:47 -0700
From:   kan.liang@...el.com
To:     tglx@...utronix.de, peterz@...radead.org, mingo@...hat.com,
        linux-kernel@...r.kernel.org
Cc:     acme@...nel.org, eranian@...gle.com, ak@...ux.intel.com,
        Kan Liang <Kan.liang@...el.com>
Subject: [PATCH V4 2/8] perf/x86/intel/uncore: correct fixed counter index check for NHM

From: Kan Liang <Kan.liang@...el.com>

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@...el.com>
---

Changes since V3:
 - New patch for similar '>=' issue on NHM.

 arch/x86/events/intel/uncore_nhmex.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/uncore_nhmex.c b/arch/x86/events/intel/uncore_nhmex.c
index 6a5cbe9..6f0d0da 100644
--- a/arch/x86/events/intel/uncore_nhmex.c
+++ b/arch/x86/events/intel/uncore_nhmex.c
@@ -245,7 +245,7 @@ static void nhmex_uncore_msr_enable_event(struct intel_uncore_box *box, struct p
 {
 	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);
-- 
2.7.4