1 #ifndef _ASM_X86_PVCLOCK_H
2 #define _ASM_X86_PVCLOCK_H
4 #include <linux/clocksource.h>
5 #include <asm/pvclock-abi.h>
7 /* some helper functions for xen and kvm pv clock sources */
8 cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
9 void pvclock_set_flags(u8 flags);
10 unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
11 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
12 struct pvclock_vcpu_time_info *vcpu,
14 void pvclock_resume(void);
17 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
18 * yielding a 64-bit result.
20 static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
43 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
44 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
45 #elif defined(__x86_64__)
47 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
51 [mul_frac]"rm"((u64)mul_frac));
59 static __always_inline
60 u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src)
62 u64 delta = __native_read_tsc() - src->tsc_timestamp;
63 return pvclock_scale_delta(delta, src->tsc_to_system_mul,
67 static __always_inline
68 unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src,
69 cycle_t *cycles, u8 *flags)
75 version = src->version;
77 offset = pvclock_get_nsec_offset(src);
78 ret = src->system_time + offset;
79 ret_flags = src->flags;
87 #endif /* _ASM_X86_PVCLOCK_H */