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| author | Leo Yan <leo.yan@linaro.org> | 2020-09-14 14:53:07 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-09-22 19:44:16 +0300 |
| commit | 4979e861415d59a479c7376e16d90df83da94bb1 (patch) | |
| tree | 4514468de531f1be2b53def8b570f33e150126a1 | |
| parent | 03fca3af51703bd77ed14c88c3d5733840a69f3f (diff) | |
| download | linux-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/Build | 1 | ||||
| -rw-r--r-- | tools/perf/arch/arm64/util/tsc.c | 21 |
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; +} |