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>

diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
index c59cc97fe6c1478225863d0d814bece995652f5a..47e25d464104b347ac348b4268434ff0a08be000 100644 (file)
--- 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 d59e606617944be07c787d704f74ff38fa3840ac..a7d90910c61a85d401e42c9c8c267f0495bd4ddf 100644 (file)
--- 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) &&