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Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_X86_PVCLOCK_H
3#define _ASM_X86_PVCLOCK_H
4
5#include <asm/clocksource.h>
6#include <asm/pvclock-abi.h>
7
8struct timespec64;
9/* some helper functions for xen and kvm pv clock sources */
10u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
11u64 pvclock_clocksource_read_nowd(struct pvclock_vcpu_time_info *src);
12u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
13void pvclock_set_flags(u8 flags);
14unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
15void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
16 struct pvclock_vcpu_time_info *vcpu,
17 struct timespec64 *ts);
18void pvclock_resume(void);
19
20void pvclock_touch_watchdogs(void);
21
22static __always_inline
23unsigned pvclock_read_begin(const struct pvclock_vcpu_time_info *src)
24{
25 unsigned version = src->version & ~1;
26 /* Make sure that the version is read before the data. */
27 virt_rmb();
28 return version;
29}
30
31static __always_inline
32bool pvclock_read_retry(const struct pvclock_vcpu_time_info *src,
33 unsigned version)
34{
35 /* Make sure that the version is re-read after the data. */
36 virt_rmb();
37 return unlikely(version != src->version);
38}
39
40/*
41 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
42 * yielding a 64-bit result.
43 */
44static __always_inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
45{
46 u64 product;
47#ifdef __i386__
48 u32 tmp1, tmp2;
49#else
50 ulong tmp;
51#endif
52
53 if (shift < 0)
54 delta >>= -shift;
55 else
56 delta <<= shift;
57
58#ifdef __i386__
59 __asm__ (
60 "mul %5 ; "
61 "mov %4,%%eax ; "
62 "mov %%edx,%4 ; "
63 "mul %5 ; "
64 "xor %5,%5 ; "
65 "add %4,%%eax ; "
66 "adc %5,%%edx ; "
67 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
68 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
69#elif defined(__x86_64__)
70 __asm__ (
71 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
72 : [lo]"=a"(product),
73 [hi]"=d"(tmp)
74 : "0"(delta),
75 [mul_frac]"rm"((u64)mul_frac));
76#else
77#error implement me!
78#endif
79
80 return product;
81}
82
83static __always_inline
84u64 __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, u64 tsc)
85{
86 u64 delta = tsc - src->tsc_timestamp;
87 u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul,
88 src->tsc_shift);
89 return src->system_time + offset;
90}
91
92struct pvclock_vsyscall_time_info {
93 struct pvclock_vcpu_time_info pvti;
94} __attribute__((__aligned__(SMP_CACHE_BYTES)));
95
96#define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
97
98#ifdef CONFIG_PARAVIRT_CLOCK
99void pvclock_set_pvti_cpu0_va(struct pvclock_vsyscall_time_info *pvti);
100struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void);
101#else
102static inline struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void)
103{
104 return NULL;
105}
106#endif
107
108#endif /* _ASM_X86_PVCLOCK_H */