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 /*
29 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
30 * yielding a 64-bit result.
31 */
pvclock_scale_delta(u64 delta,u32 mul_frac,int shift)32 static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
33 {
34 u64 product;
35 #ifdef __i386__
36 u32 tmp1, tmp2;
37 #else
38 ulong tmp;
39 #endif
40
41 if (shift < 0)
42 delta >>= -shift;
43 else
44 delta <<= shift;
45
46 #ifdef __i386__
47 __asm__ (
48 "mul %5 ; "
49 "mov %4,%%eax ; "
50 "mov %%edx,%4 ; "
51 "mul %5 ; "
52 "xor %5,%5 ; "
53 "add %4,%%eax ; "
54 "adc %5,%%edx ; "
55 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
56 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
57 #elif defined(__x86_64__)
58 __asm__ (
59 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
60 : [lo]"=a"(product),
61 [hi]"=d"(tmp)
62 : "0"(delta),
63 [mul_frac]"rm"((u64)mul_frac));
64 #else
65 #error implement me!
66 #endif
67
68 return product;
69 }
70
71 static __always_inline
pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info * src)72 u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src)
73 {
74 u64 delta = rdtsc_ordered() - src->tsc_timestamp;
75 return pvclock_scale_delta(delta, src->tsc_to_system_mul,
76 src->tsc_shift);
77 }
78
79 static __always_inline
__pvclock_read_cycles(const struct pvclock_vcpu_time_info * src,cycle_t * cycles,u8 * flags)80 unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src,
81 cycle_t *cycles, u8 *flags)
82 {
83 unsigned version;
84 cycle_t ret, offset;
85 u8 ret_flags;
86
87 version = src->version;
88 /* Make the latest version visible */
89 smp_rmb();
90
91 offset = pvclock_get_nsec_offset(src);
92 ret = src->system_time + offset;
93 ret_flags = src->flags;
94
95 *cycles = ret;
96 *flags = ret_flags;
97 return version;
98 }
99
100 struct pvclock_vsyscall_time_info {
101 struct pvclock_vcpu_time_info pvti;
102 } __attribute__((__aligned__(SMP_CACHE_BYTES)));
103
104 #define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
105 #define PVCLOCK_VSYSCALL_NR_PAGES (((NR_CPUS-1)/(PAGE_SIZE/PVTI_SIZE))+1)
106
107 int __init pvclock_init_vsyscall(struct pvclock_vsyscall_time_info *i,
108 int size);
109 struct pvclock_vcpu_time_info *pvclock_get_vsyscall_time_info(int cpu);
110
111 #endif /* _ASM_X86_PVCLOCK_H */
112