1 #ifndef _ASM_X86_PVCLOCK_H
2 #define _ASM_X86_PVCLOCK_H
3
4 #include <linux/clocksource.h>
5 #include <asm/pvclock-abi.h>
6
7 #ifdef CONFIG_KVM_GUEST
8 extern struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void);
9 #else
pvclock_pvti_cpu0_va(void)10 static inline struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void)
11 {
12 return NULL;
13 }
14 #endif
15
16 /* some helper functions for xen and kvm pv clock sources */
17 cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
18 u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
19 void pvclock_set_flags(u8 flags);
20 unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
21 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
22 struct pvclock_vcpu_time_info *vcpu,
23 struct timespec *ts);
24 void pvclock_resume(void);
25
26 void pvclock_touch_watchdogs(void);
27
28 static __always_inline
pvclock_read_begin(const struct pvclock_vcpu_time_info * src)29 unsigned pvclock_read_begin(const struct pvclock_vcpu_time_info *src)
30 {
31 unsigned version = src->version & ~1;
32 /* Make sure that the version is read before the data. */
33 virt_rmb();
34 return version;
35 }
36
37 static __always_inline
pvclock_read_retry(const struct pvclock_vcpu_time_info * src,unsigned version)38 bool pvclock_read_retry(const struct pvclock_vcpu_time_info *src,
39 unsigned version)
40 {
41 /* Make sure that the version is re-read after the data. */
42 virt_rmb();
43 return unlikely(version != src->version);
44 }
45
46 /*
47 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
48 * yielding a 64-bit result.
49 */
pvclock_scale_delta(u64 delta,u32 mul_frac,int shift)50 static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
51 {
52 u64 product;
53 #ifdef __i386__
54 u32 tmp1, tmp2;
55 #else
56 ulong tmp;
57 #endif
58
59 if (shift < 0)
60 delta >>= -shift;
61 else
62 delta <<= shift;
63
64 #ifdef __i386__
65 __asm__ (
66 "mul %5 ; "
67 "mov %4,%%eax ; "
68 "mov %%edx,%4 ; "
69 "mul %5 ; "
70 "xor %5,%5 ; "
71 "add %4,%%eax ; "
72 "adc %5,%%edx ; "
73 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
74 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
75 #elif defined(__x86_64__)
76 __asm__ (
77 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
78 : [lo]"=a"(product),
79 [hi]"=d"(tmp)
80 : "0"(delta),
81 [mul_frac]"rm"((u64)mul_frac));
82 #else
83 #error implement me!
84 #endif
85
86 return product;
87 }
88
89 static __always_inline
__pvclock_read_cycles(const struct pvclock_vcpu_time_info * src,u64 tsc)90 cycle_t __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src,
91 u64 tsc)
92 {
93 u64 delta = tsc - src->tsc_timestamp;
94 cycle_t offset = pvclock_scale_delta(delta, src->tsc_to_system_mul,
95 src->tsc_shift);
96 return src->system_time + offset;
97 }
98
99 struct pvclock_vsyscall_time_info {
100 struct pvclock_vcpu_time_info pvti;
101 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
102
103 #define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
104
105 #endif /* _ASM_X86_PVCLOCK_H */
106