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