linux-kernel - [PATCH v4 04/12] arm-cci: Fix the flags for pmu_start called from pmu

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Message-Id: <1450374559-23315-5-git-send-email-suzuki.poulose@arm.com>
Date:	Thu, 17 Dec 2015 17:49:11 +0000
From:	"Suzuki K. Poulose" <suzuki.poulose@....com>
To:	linux-arm-kernel@...ts.infradead.org
Cc:	linux-kernel@...r.kernel.org, mark.rutland@....com,
	punit.agrawal@....com, arm@...nel.org,
	"Suzuki K. Poulose" <suzuki.poulose@....com>
Subject: [PATCH v4 04/12] arm-cci: Fix the flags for pmu_start called from pmu_add

The cci PMU always reprograms the counter value in pmu->start()
irrespective of the mode it is called from, making sure that
the hwc->state is PERF_HES_UPTODATE.

When pmu->add() is called with PERF_EF_START, we invoke
pmu->start() with PERF_EF_RELOAD removing the PERF_EF_START.
This makes it impossible to detect where the pmu->start()
is called from, i.e, PERF_EF_START or a real PERF_EF_RELOAD.

This patch fixes the issue by, passing the right flags down
to the pmu->start() when called from pmu->add().

Cc: Mark Rutland <mark.rutland@....com>
Cc: Punit Agrawal <punit.agrawal@....com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@....com>
---
 drivers/bus/arm-cci.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index f6b8717..f00cbce 100644
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -1020,7 +1020,7 @@ static int cci_pmu_add(struct perf_event *event, int flags)
 
 	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
 	if (flags & PERF_EF_START)
-		cci_pmu_start(event, PERF_EF_RELOAD);
+		cci_pmu_start(event, flags);
 
 	/* Propagate our changes to the userspace mapping. */
 	perf_event_update_userpage(event);
-- 
1.7.9.5

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