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authorLeo Yan <leo.yan@linaro.org>2020-09-14 14:53:07 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2020-09-22 19:44:16 +0300
commit4979e861415d59a479c7376e16d90df83da94bb1 (patch)
tree4514468de531f1be2b53def8b570f33e150126a1
parent03fca3af51703bd77ed14c88c3d5733840a69f3f (diff)
downloadlinux-4979e861415d59a479c7376e16d90df83da94bb1.tar.xz
perf tsc: Add rdtsc() for Arm64
The system register CNTVCT_EL0 can be used to retrieve the counter from user space. Add rdtsc() for Arm64. Signed-off-by: Leo Yan <leo.yan@linaro.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Gustavo A. R. Silva <gustavoars@kernel.org> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: John Garry <john.garry@huawei.com> Cc: Kemeng Shi <shikemeng@huawei.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Nick Gasson <nick.gasson@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Remi Bernon <rbernon@codeweavers.com> Cc: Stephane Eranian <eranian@google.com> Cc: Steve Maclean <steve.maclean@microsoft.com> Cc: Will Deacon <will@kernel.org> Cc: Zou Wei <zou_wei@huawei.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lore.kernel.org/lkml/20200914115311.2201-3-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-rw-r--r--tools/perf/arch/arm64/util/Build1
-rw-r--r--tools/perf/arch/arm64/util/tsc.c21
2 files changed, 22 insertions, 0 deletions
diff --git a/tools/perf/arch/arm64/util/Build b/tools/perf/arch/arm64/util/Build
index 5c13438c7bd4..b53294d74b01 100644
--- a/tools/perf/arch/arm64/util/Build
+++ b/tools/perf/arch/arm64/util/Build
@@ -1,6 +1,7 @@
perf-y += header.o
perf-y += machine.o
perf-y += perf_regs.o
+perf-y += tsc.o
perf-$(CONFIG_DWARF) += dwarf-regs.o
perf-$(CONFIG_LOCAL_LIBUNWIND) += unwind-libunwind.o
perf-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
diff --git a/tools/perf/arch/arm64/util/tsc.c b/tools/perf/arch/arm64/util/tsc.c
new file mode 100644
index 000000000000..cc85bd9e73f1
--- /dev/null
+++ b/tools/perf/arch/arm64/util/tsc.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/types.h>
+
+#include "../../../util/tsc.h"
+
+u64 rdtsc(void)
+{
+ u64 val;
+
+ /*
+ * According to ARM DDI 0487F.c, from Armv8.0 to Armv8.5 inclusive, the
+ * system counter is at least 56 bits wide; from Armv8.6, the counter
+ * must be 64 bits wide. So the system counter could be less than 64
+ * bits wide and it is attributed with the flag 'cap_user_time_short'
+ * is true.
+ */
+ asm volatile("mrs %0, cntvct_el0" : "=r" (val));
+
+ return val;
+}