From: Leo Yan <leo.yan@linaro.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Adrian Hunter <adrian.hunter@intel.com>,
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>,
Will Deacon <will@kernel.org>,
Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@linaro.org>,
John Garry <john.garry@huawei.com>,
Andi Kleen <ak@linux.intel.com>,
Riccardo Mancini <rickyman7@gmail.com>,
Jin Yao <yao.jin@linux.intel.com>,
Li Huafei <lihuafei1@huawei.com>,
coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v1 3/3] perf auxtrace arm: Support compat_auxtrace_mmap__{read_head|write_tail}
Date: Mon, 9 Aug 2021 19:27:27 +0800 [thread overview]
Message-ID: <20210809112727.596876-4-leo.yan@linaro.org> (raw)
In-Reply-To: <20210809112727.596876-1-leo.yan@linaro.org>
When the tool runs with compat mode on Arm platform, the kernel is in
64-bit mode and user space is in 32-bit mode; the user space can use
instructions "ldrd" and "strd" for 64-bit value atomicity.
This patch adds compat_auxtrace_mmap__{read_head|write_tail} for arm
building, it uses "ldrd" and "strd" instructions to ensure accessing
atomicity for aux head and tail. The file arch/arm/util/auxtrace.c is
built for arm and arm64 building, these two functions are not needed for
arm64, so check the compiler macro "__arm__" to only include them for
arm building.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
tools/perf/arch/arm/util/auxtrace.c | 32 +++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/tools/perf/arch/arm/util/auxtrace.c b/tools/perf/arch/arm/util/auxtrace.c
index b187bddbd01a..c7c7ec0812d5 100644
--- a/tools/perf/arch/arm/util/auxtrace.c
+++ b/tools/perf/arch/arm/util/auxtrace.c
@@ -107,3 +107,35 @@ struct auxtrace_record
*err = 0;
return NULL;
}
+
+#if defined(__arm__)
+u64 compat_auxtrace_mmap__read_head(struct auxtrace_mmap *mm)
+{
+ struct perf_event_mmap_page *pc = mm->userpg;
+ u64 result;
+
+ __asm__ __volatile__(
+" ldrd %0, %H0, [%1]"
+ : "=&r" (result)
+ : "r" (&pc->aux_head), "Qo" (pc->aux_head)
+ );
+
+ return result;
+}
+
+int compat_auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail)
+{
+ struct perf_event_mmap_page *pc = mm->userpg;
+
+ /* Ensure all reads are done before we write the tail out */
+ smp_mb();
+
+ __asm__ __volatile__(
+" strd %2, %H2, [%1]"
+ : "=Qo" (pc->aux_tail)
+ : "r" (&pc->aux_tail), "r" (tail)
+ );
+
+ return 0;
+}
+#endif
--
2.25.1
next prev parent reply other threads:[~2021-08-09 11:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-09 11:27 [PATCH v1 0/3] perf: Support compat mode for AUX ring buffer Leo Yan
2021-08-09 11:27 ` [PATCH v1 1/3] perf env: Track kernel 64-bit mode in environment Leo Yan
2021-08-09 20:11 ` Arnaldo Carvalho de Melo
2021-08-09 11:27 ` [PATCH v1 2/3] perf auxtrace: Add compat_auxtrace_mmap__{read_head|write_tail} Leo Yan
2021-08-09 20:12 ` Arnaldo Carvalho de Melo
2021-08-12 9:23 ` Adrian Hunter
2021-08-13 16:22 ` James Clark
2021-08-23 9:51 ` Leo Yan
2021-08-23 10:57 ` James Clark
2021-08-23 12:13 ` Leo Yan
2021-08-23 16:00 ` James Clark
2021-08-24 2:13 ` Leo Yan
2021-08-09 11:27 ` Leo Yan [this message]
2021-08-23 12:23 ` [PATCH v1 3/3] perf auxtrace arm: Support compat_auxtrace_mmap__{read_head|write_tail} James Clark
2021-08-23 13:30 ` Leo Yan
2021-08-23 13:39 ` Russell King (Oracle)
2021-08-23 14:54 ` Leo Yan
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