1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
#ifndef _ASM_X86_PVCLOCK_H
#define _ASM_X86_PVCLOCK_H
#include <linux/clocksource.h>
#include <asm/pvclock-abi.h>
/* some helper functions for xen and kvm pv clock sources */
cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
void pvclock_set_flags(u8 flags);
unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
struct pvclock_vcpu_time_info *vcpu,
struct timespec *ts);
void pvclock_resume(void);
/*
* Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
* yielding a 64-bit result.
*/
static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
{
u64 product;
#ifdef __i386__
u32 tmp1, tmp2;
#else
ulong tmp;
#endif
if (shift < 0)
delta >>= -shift;
else
delta <<= shift;
#ifdef __i386__
__asm__ (
"mul %5 ; "
"mov %4,%%eax ; "
"mov %%edx,%4 ; "
"mul %5 ; "
"xor %5,%5 ; "
"add %4,%%eax ; "
"adc %5,%%edx ; "
: "=A" (product), "=r" (tmp1), "=r" (tmp2)
: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
#elif defined(__x86_64__)
__asm__ (
"mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
: [lo]"=a"(product),
[hi]"=d"(tmp)
: "0"(delta),
[mul_frac]"rm"((u64)mul_frac));
#else
#error implement me!
#endif
return product;
}
static __always_inline
u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src)
{
u64 delta = __native_read_tsc() - src->tsc_timestamp;
return pvclock_scale_delta(delta, src->tsc_to_system_mul,
src->tsc_shift);
}
static __always_inline
unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src,
cycle_t *cycles, u8 *flags)
{
unsigned version;
cycle_t ret, offset;
u8 ret_flags;
version = src->version;
/* Note: emulated platforms which do not advertise SSE2 support
* result in kvmclock not using the necessary RDTSC barriers.
* Without barriers, it is possible that RDTSC instruction reads from
* the time stamp counter outside rdtsc_barrier protected section
* below, resulting in violation of monotonicity.
*/
rdtsc_barrier();
offset = pvclock_get_nsec_offset(src);
ret = src->system_time + offset;
ret_flags = src->flags;
rdtsc_barrier();
*cycles = ret;
*flags = ret_flags;
return version;
}
struct pvclock_vsyscall_time_info {
struct pvclock_vcpu_time_info pvti;
} __attribute__((__aligned__(SMP_CACHE_BYTES)));
#define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
#define PVCLOCK_VSYSCALL_NR_PAGES (((NR_CPUS-1)/(PAGE_SIZE/PVTI_SIZE))+1)
int __init pvclock_init_vsyscall(struct pvclock_vsyscall_time_info *i,
int size);
struct pvclock_vcpu_time_info *pvclock_get_vsyscall_time_info(int cpu);
#endif /* _ASM_X86_PVCLOCK_H */
|
