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 : ""(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, src->tsc_to_system_mul,
87 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
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