arm64: perf: Only advertise cap_user_time for arch_timer

When sched_clock is running on anything other than arch_timer, don't
advertise cap_user_time*.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Link: https://lore.kernel.org/r/20200716051130.4359-5-leo.yan@linaro.org
Requested-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 3bbbc22a51482910e6dff9d97557e88f258469c5..674edc7ba8ca2c00c9ac47515b21038d164f2dc7 100644 (file)
--- 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>
@@ -1173,16 +1175,15 @@ void arch_perf_update_userpage(struct perf_event *event,
        unsigned int seq;
        u64 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;
@@ -1212,4 +1213,10 @@ 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;
 }