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 */
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_resume(void);
14
15 void pvclock_touch_watchdogs(void);
16
17 static __always_inline
18 unsigned 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
26 static __always_inline
27 bool 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 */
39 static 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 : ""(delta),
70 [mul_frac]"rm"((u64)mul_frac));
71 #else
72 #error implement me!
73 #endif
74
75 return product;
76 }
77
78 static __always_inline
79 u64 __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
87 struct 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
94 void pvclock_set_pvti_cpu0_va(struct pvclock_vsyscall_time_info *pvti);
95 struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void);
96 #else
97 static 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
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