linux-kernel - [tip:perf/core] perf/x86/intel/uncore: Correct fixed counter index check for NHM

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Date:   Thu, 31 May 2018 05:30:33 -0700
From:   tip-bot for Kan Liang <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     kan.liang@...el.com, linux-kernel@...r.kernel.org,
        torvalds@...ux-foundation.org, mingo@...nel.org, hpa@...or.com,
        peterz@...radead.org, tglx@...utronix.de
Subject: [tip:perf/core] perf/x86/intel/uncore: Correct fixed counter index
 check for NHM

Commit-ID:  d71f11c076c420c4e2fceb4faefa144e055e0935
Gitweb:     https://git.kernel.org/tip/d71f11c076c420c4e2fceb4faefa144e055e0935
Author:     Kan Liang <kan.liang@...el.com>
AuthorDate: Thu, 3 May 2018 11:25:07 -0700
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 31 May 2018 12:36:28 +0200

perf/x86/intel/uncore: Correct fixed counter index check for NHM

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>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: acme@...nel.org
Cc: eranian@...gle.com
Link: http://lkml.kernel.org/r/1525371913-10597-2-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 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 93e7a8397cde..173e2674be6e 100644
--- a/arch/x86/events/intel/uncore_nhmex.c
+++ b/arch/x86/events/intel/uncore_nhmex.c
@@ -246,7 +246,7 @@ 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);