From: Peter Zijlstra <pet...@infradead.org>
When sched_clock is running on anything other than arch_timer, don't
advertise cap_user_time*.
Requested-by: Will Deacon <w...@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
arch/arm64/kernel/perf_event.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 35c2c737d4af..76f6afd28b48 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -13,6 +13,8 @@
#include <asm/sysreg.h>
#include <asm/virt.h>
+#include <clocksource/arm_arch_timer.h>
+
#include <linux/acpi.h>
#include <linux/clocksource.h>
#include <linux/kvm_host.h>
@@ -1170,16 +1172,15 @@ void arch_perf_update_userpage(struct perf_event *event,
unsigned int seq;
u64 quot, rem, ns;
- /*
- * Internal timekeeping for enabled/running/stopped times
- * is always computed with the sched_clock.
- */
- userpg->cap_user_time = 1;
- userpg->cap_user_time_zero = 1;
+ userpg->cap_user_time = 0;
+ userpg->cap_user_time_zero = 0;
do {
rd = sched_clock_read_begin(&seq);
+ if (rd->read_sched_clock != arch_timer_read_counter)
+ return;
+
userpg->time_mult = rd->mult;
userpg->time_shift = rd->shift;
userpg->time_zero = rd->epoch_ns;
@@ -1211,4 +1212,10 @@ void arch_perf_update_userpage(struct perf_event *event,
userpg->time_mult >>= 1;
}
+ /*
+ * Internal timekeeping for enabled/running/stopped times
+ * is always computed with the sched_clock.
+ */
+ userpg->cap_user_time = 1;
+ userpg->cap_user_time_zero = 1;
}
--
2.17.1
