Commit 4979e861 authored Sep 14, 2020 by Leo Yan Committed by Arnaldo Carvalho de Melo Sep 22, 2020

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>

parent 03fca3af

tools/perf/arch/arm64/util/Build

+1 −0

Original line number	Diff line number	Diff line
		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

tools/perf/arch/arm64/util/tsc.c

0 → 100644

+21 −0

Original line number	Diff line number	Diff line
		// 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;
		}

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