linux-kernel - [PATCH v2 07/20] arm: perf: conditionally advertise PMU exclusion capability

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Date:   Mon, 26 Nov 2018 11:12:23 +0000
From:   Andrew Murray <andrew.murray@....com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Will Deacon <will.deacon@....com>,
        Mark Rutland <mark.rutland@....com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>, x86@...nel.org,
        Ralf Baechle <ralf@...ux-mips.org>,
        Paul Burton <paul.burton@...s.com>,
        James Hogan <jhogan@...nel.org>,
        Martin Schwidefsky <schwidefsky@...ibm.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        "David S . Miller" <davem@...emloft.net>,
        sparclinux@...r.kernel.org, Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-s390@...r.kernel.org, linux-mips@...ux-mips.org,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-alpha@...r.kernel.org
Subject: [PATCH v2 07/20] arm: perf: conditionally advertise PMU exclusion capability

The ARM PMU driver can be used to represent a variety of ARM based
PMUs. Some of these PMUs provide support for context exclusion, where
this is the case we advertise this via the PERF_PMU_CAP_EXCLUDE
capability to ensure that perf doesn't prevent us from handling events
where any exclusion flags are set.

Signed-off-by: Andrew Murray <andrew.murray@....com>
---
 drivers/perf/arm_pmu.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 7f01f6f..4409035 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -357,13 +357,6 @@ static irqreturn_t armpmu_dispatch_irq(int irq, void *dev)
 }
 
 static int
-event_requires_mode_exclusion(struct perf_event_attr *attr)
-{
-	return attr->exclude_idle || attr->exclude_user ||
-	       attr->exclude_kernel || attr->exclude_hv;
-}
-
-static int
 __hw_perf_event_init(struct perf_event *event)
 {
 	struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
@@ -393,9 +386,8 @@ __hw_perf_event_init(struct perf_event *event)
 	/*
 	 * Check whether we need to exclude the counter from certain modes.
 	 */
-	if ((!armpmu->set_event_filter ||
-	     armpmu->set_event_filter(hwc, &event->attr)) &&
-	     event_requires_mode_exclusion(&event->attr)) {
+	if (armpmu->set_event_filter &&
+	    armpmu->set_event_filter(hwc, &event->attr)) {
 		pr_debug("ARM performance counters do not support "
 			 "mode exclusion\n");
 		return -EOPNOTSUPP;
@@ -861,6 +853,9 @@ int armpmu_register(struct arm_pmu *pmu)
 	if (ret)
 		return ret;
 
+	if (pmu->set_event_filter)
+		pmu->pmu.capabilities |= PERF_PMU_CAP_EXCLUDE;
+
 	ret = perf_pmu_register(&pmu->pmu, pmu->name, -1);
 	if (ret)
 		goto out_destroy;
-- 
2.7.4