From dce2db0a35197e2f4421245079f19ab753e97348 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Tue, 27 Nov 2012 23:28:51 -0200 Subject: [PATCH] x86: pvclock: create helper for pvclock data retrieval Originally from Jeremy Fitzhardinge. So code can be reused. Acked-by: Glauber Costa Signed-off-by: Marcelo Tosatti --- arch/x86/include/asm/pvclock.h | 28 ++++++++++++++++++++++++++++ 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) && -- 2.20.1