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