perf auxtrace: Change to use SMP memory barriers

The kernel and the userspace tool can access the AUX ring buffer head
and tail from different CPUs, thus SMP class of barriers are required
on SMP system.

This patch changes to use SMP barriers to replace mb() and rmb()
barriers.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: x86@kernel.org
Link: http://lore.kernel.org/lkml/20210602103007.184993-6-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
index efca761..cc1c1b9 100644 (file)
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -452,7 +452,7 @@ static inline u64 auxtrace_mmap__read_snapshot_head(struct auxtrace_mmap *mm)
        u64 head = READ_ONCE(pc->aux_head);
 
        /* Ensure all reads are done after we read the head */
-       rmb();
+       smp_rmb();
        return head;
 }
 
@@ -466,7 +466,7 @@ static inline u64 auxtrace_mmap__read_head(struct auxtrace_mmap *mm)
 #endif
 
        /* Ensure all reads are done after we read the head */
-       rmb();
+       smp_rmb();
        return head;
 }
 
@@ -478,7 +478,7 @@ static inline void auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail)
 #endif
 
        /* Ensure all reads are done before we write the tail out */
-       mb();
+       smp_mb();
 #if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
        pc->aux_tail = tail;
 #else