1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_PVCLOCK_H
3 #define _ASM_X86_PVCLOCK_H
5 #include <asm/clocksource.h>
6 #include <asm/pvclock-abi.h>
8 /* some helper functions for xen and kvm pv clock sources */
9 u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
10 u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
11 void pvclock_set_flags(u8 flags);
12 unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
13 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
14 struct pvclock_vcpu_time_info *vcpu,
15 struct timespec64 *ts);
16 void pvclock_resume(void);
18 void pvclock_touch_watchdogs(void);
20 static __always_inline
21 unsigned pvclock_read_begin(const struct pvclock_vcpu_time_info *src)
23 unsigned version = src->version & ~1;
24 /* Make sure that the version is read before the data. */
29 static __always_inline
30 bool pvclock_read_retry(const struct pvclock_vcpu_time_info *src,
33 /* Make sure that the version is re-read after the data. */
35 return unlikely(version != src->version);
39 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
40 * yielding a 64-bit result.
42 static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
65 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
66 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
67 #elif defined(__x86_64__)
69 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
73 [mul_frac]"rm"((u64)mul_frac));
81 static __always_inline
82 u64 __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, u64 tsc)
84 u64 delta = tsc - src->tsc_timestamp;
85 u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul,
87 return src->system_time + offset;
90 struct pvclock_vsyscall_time_info {
91 struct pvclock_vcpu_time_info pvti;
92 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
94 #define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
96 #ifdef CONFIG_PARAVIRT_CLOCK
97 void pvclock_set_pvti_cpu0_va(struct pvclock_vsyscall_time_info *pvti);
98 struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void);
100 static inline struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void)
106 #endif /* _ASM_X86_PVCLOCK_H */