diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2023-01-26 16:08:36 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-01-31 15:01:47 +0100 |
| commit | 8739c6811572b087decd561f96382087402cc343 (patch) | |
| tree | 60330c4df92998fd1994afa131ebab2b24ca67b2 /arch/x86/kernel/pvclock.c | |
| parent | 5c9da9fe826d4a0d84bb322cca27cc8ad8d23b24 (diff) | |
sched/clock/x86: Mark sched_clock() noinstr
In order to use sched_clock() from noinstr code, mark it and all it's
implenentations noinstr.
The whole pvclock thing (used by KVM/Xen) is a bit of a pain,
since it calls out to watchdogs, create a
pvclock_clocksource_read_nowd() variant doesn't do that and can be
noinstr.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230126151323.702003578@infradead.org
Diffstat (limited to 'arch/x86/kernel/pvclock.c')
| -rw-r--r-- | arch/x86/kernel/pvclock.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c index 5a2a517dd61b..56acf53a782a 100644 --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -64,7 +64,8 @@ u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src) return flags & valid_flags; } -u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src) +static __always_inline +u64 __pvclock_clocksource_read(struct pvclock_vcpu_time_info *src, bool dowd) { unsigned version; u64 ret; @@ -77,7 +78,7 @@ u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src) flags = src->flags; } while (pvclock_read_retry(src, version)); - if (unlikely((flags & PVCLOCK_GUEST_STOPPED) != 0)) { + if (dowd && unlikely((flags & PVCLOCK_GUEST_STOPPED) != 0)) { src->flags &= ~PVCLOCK_GUEST_STOPPED; pvclock_touch_watchdogs(); } @@ -100,15 +101,25 @@ u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src) * updating at the same time, and one of them could be slightly behind, * making the assumption that last_value always go forward fail to hold. */ - last = atomic64_read(&last_value); + last = arch_atomic64_read(&last_value); do { if (ret <= last) return last; - } while (!atomic64_try_cmpxchg(&last_value, &last, ret)); + } while (!arch_atomic64_try_cmpxchg(&last_value, &last, ret)); return ret; } +u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src) +{ + return __pvclock_clocksource_read(src, true); +} + +noinstr u64 pvclock_clocksource_read_nowd(struct pvclock_vcpu_time_info *src) +{ + return __pvclock_clocksource_read(src, false); +} + void pvclock_read_wallclock(struct pvclock_wall_clock *wall_clock, struct pvclock_vcpu_time_info *vcpu_time, struct timespec64 *ts) |