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From:   Leo Yan <leo.yan@linaro.org>
To:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Mike Leach <mike.leach@linaro.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Andi Kleen <ak@linux.intel.com>,
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        coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org
Cc:     Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v2 4/8] perf/x86: Add barrier after updating bts
Date:   Wed,  2 Jun 2021 18:30:03 +0800
Message-Id: <20210602103007.184993-5-leo.yan@linaro.org>
In-Reply-To: <20210602103007.184993-1-leo.yan@linaro.org>
References: <20210602103007.184993-1-leo.yan@linaro.org>
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Add barrier wmb() to separate the AUX data store and aux_head store.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 arch/x86/events/intel/bts.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c
index 6320d2cfd9d3..4a015d160bc5 100644
--- a/arch/x86/events/intel/bts.c
+++ b/arch/x86/events/intel/bts.c
@@ -209,6 +209,9 @@ static void bts_update(struct bts_ctx *bts)
 	} else {
 		local_set(&buf->data_size, head);
 	}
+
+	/* The WMB separates data store and aux_head store matches. */
+	wmb();
 }
 
 static int
-- 
2.25.1