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 u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
10 void pvclock_set_flags(u8 flags);
11 unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
12 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
13 struct pvclock_vcpu_time_info *vcpu,
15 void pvclock_resume(void);
17 void pvclock_touch_watchdogs(void);
20 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
21 * yielding a 64-bit result.
23 static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
46 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
47 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
48 #elif defined(__x86_64__)
50 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
54 [mul_frac]"rm"((u64)mul_frac));
62 static __always_inline
63 u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src)
65 u64 delta = __native_read_tsc() - src->tsc_timestamp;
66 return pvclock_scale_delta(delta, src->tsc_to_system_mul,
70 static __always_inline
71 unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src,
72 cycle_t *cycles, u8 *flags)
78 version = src->version;
79 /* Note: emulated platforms which do not advertise SSE2 support
80 * result in kvmclock not using the necessary RDTSC barriers.
81 * Without barriers, it is possible that RDTSC instruction reads from
82 * the time stamp counter outside rdtsc_barrier protected section
83 * below, resulting in violation of monotonicity.
86 offset = pvclock_get_nsec_offset(src);
87 ret = src->system_time + offset;
88 ret_flags = src->flags;
96 struct pvclock_vsyscall_time_info {
97 struct pvclock_vcpu_time_info pvti;
98 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
100 #define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
101 #define PVCLOCK_VSYSCALL_NR_PAGES (((NR_CPUS-1)/(PAGE_SIZE/PVTI_SIZE))+1)
103 int __init pvclock_init_vsyscall(struct pvclock_vsyscall_time_info *i,
105 struct pvclock_vcpu_time_info *pvclock_get_vsyscall_time_info(int cpu);
107 #endif /* _ASM_X86_PVCLOCK_H */