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| author | Peter Zijlstra <peterz@infradead.org> | 2020-07-16 13:11:29 +0800 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-07-20 11:50:47 +0100 |
| commit | c8f9eb0d6ebaa768c9f6eb2ee21b01d74230934d (patch) | |
| tree | 03772aad1ee942bebaadd116f0f423d67ddf1852 /arch/arm64/kernel | |
| parent | 6c0246a4588d418f72acd40a7b7601be403d80a9 (diff) | |
| download | lwn-c8f9eb0d6ebaa768c9f6eb2ee21b01d74230934d.tar.gz lwn-c8f9eb0d6ebaa768c9f6eb2ee21b01d74230934d.zip | |
arm64: perf: Add cap_user_time_short
This completes the ARM64 cap_user_time support.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Link: https://lore.kernel.org/r/20200716051130.4359-7-leo.yan@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/perf_event.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index 674edc7ba8ca..fdb6029c9021 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -1177,6 +1177,7 @@ void arch_perf_update_userpage(struct perf_event *event, userpg->cap_user_time = 0; userpg->cap_user_time_zero = 0; + userpg->cap_user_time_short = 0; do { rd = sched_clock_read_begin(&seq); @@ -1187,13 +1188,13 @@ void arch_perf_update_userpage(struct perf_event *event, userpg->time_mult = rd->mult; userpg->time_shift = rd->shift; userpg->time_zero = rd->epoch_ns; + userpg->time_cycles = rd->epoch_cyc; + userpg->time_mask = rd->sched_clock_mask; /* - * This isn't strictly correct, the ARM64 counter can be - * 'short' and then we get funnies when it wraps. The correct - * thing would be to extend the perf ABI with a cycle and mask - * value, but because wrapping on ARM64 is very rare in - * practise this 'works'. + * Subtract the cycle base, such that software that + * doesn't know about cap_user_time_short still 'works' + * assuming no wraps. */ ns = mul_u64_u32_shr(rd->epoch_cyc, rd->mult, rd->shift); userpg->time_zero -= ns; @@ -1219,4 +1220,5 @@ void arch_perf_update_userpage(struct perf_event *event, */ userpg->cap_user_time = 1; userpg->cap_user_time_zero = 1; + userpg->cap_user_time_short = 1; } |