Originally from Jeremy Fitzhardinge.
So code can be reused.
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Index: vsyscall/arch/x86/kernel/pvclock.c
===================================================================
--- vsyscall.orig/arch/x86/kernel/pvclock.c
+++ vsyscall/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) &&
Index: vsyscall/arch/x86/include/asm/pvclock.h
===================================================================
--- vsyscall.orig/arch/x86/include/asm/pvclock.h
+++ vsyscall/arch/x86/include/asm/pvclock.h
@@ -56,4 +56,32 @@ static inline u64 pvclock_scale_delta(u6
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 */
--
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