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| author | Marcelo Tosatti <mtosatti@redhat.com> | 2012-11-27 23:28:51 -0200 |
|---|---|---|
| committer | Marcelo Tosatti <mtosatti@redhat.com> | 2012-11-27 23:29:07 -0200 |
| commit | dce2db0a35197e2f4421245079f19ab753e97348 (patch) | |
| tree | c3151bef0ca980cf1c1af1fa6c4585df41e5a760 | |
| parent | 42b5637d6989f75a7a0e8ea8633583564ff443ff (diff) | |
| download | linux-dce2db0a35197e2f4421245079f19ab753e97348.tar.bz2 | |
x86: pvclock: create helper for pvclock data retrieval
Originally from Jeremy Fitzhardinge.
So code can be reused.
Acked-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| -rw-r--r-- | arch/x86/include/asm/pvclock.h | 28 | ||||
| -rw-r--r-- | arch/x86/kernel/pvclock.c | 16 |
2 files changed, 30 insertions, 14 deletions
diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h index c59cc97fe6c1..47e25d464104 100644 --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -56,4 +56,32 @@ static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift) return product; } +static __always_inline +u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src) +{ + u64 delta = __native_read_tsc() - src->tsc_timestamp; + return pvclock_scale_delta(delta, src->tsc_to_system_mul, + src->tsc_shift); +} + +static __always_inline +unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, + cycle_t *cycles, u8 *flags) +{ + unsigned version; + cycle_t ret, offset; + u8 ret_flags; + + version = src->version; + rdtsc_barrier(); + offset = pvclock_get_nsec_offset(src); + ret = src->system_time + offset; + ret_flags = src->flags; + rdtsc_barrier(); + + *cycles = ret; + *flags = ret_flags; + return version; +} + #endif /* _ASM_X86_PVCLOCK_H */ diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c index d59e60661794..a7d90910c61a 100644 --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -26,13 +26,6 @@ void pvclock_set_flags(u8 flags) valid_flags = flags; } -static u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src) -{ - u64 delta = native_read_tsc() - src->tsc_timestamp; - return pvclock_scale_delta(delta, src->tsc_to_system_mul, - src->tsc_shift); -} - unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src) { u64 pv_tsc_khz = 1000000ULL << 32; @@ -55,17 +48,12 @@ void pvclock_resume(void) cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src) { unsigned version; - cycle_t ret, offset; + cycle_t ret; u64 last; u8 flags; do { - version = src->version; - rdtsc_barrier(); - offset = pvclock_get_nsec_offset(src); - ret = src->system_time + offset; - flags = src->flags; - rdtsc_barrier(); + version = __pvclock_read_cycles(src, &ret, &flags); } while ((src->version & 1) || version != src->version); if ((valid_flags & PVCLOCK_TSC_STABLE_BIT) && |