summaryrefslogtreecommitdiffstats
path: root/tools/perf/arch/arm64/util/tsc.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--tools/perf/arch/arm64/util/tsc.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/tools/perf/arch/arm64/util/tsc.c b/tools/perf/arch/arm64/util/tsc.c
new file mode 100644
index 000000000..cc85bd9e7
--- /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;
+}