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1965aae3 PA |
1 | #ifndef _ASM_X86_PVCLOCK_H |
2 | #define _ASM_X86_PVCLOCK_H | |
7af192c9 GH |
3 | |
4 | #include <linux/clocksource.h> | |
5 | #include <asm/pvclock-abi.h> | |
6 | ||
7 | /* some helper functions for xen and kvm pv clock sources */ | |
8 | cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src); | |
2697902b | 9 | u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src); |
424c32f1 | 10 | void pvclock_set_flags(u8 flags); |
3807f345 | 11 | unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src); |
7af192c9 GH |
12 | void pvclock_read_wallclock(struct pvclock_wall_clock *wall, |
13 | struct pvclock_vcpu_time_info *vcpu, | |
14 | struct timespec *ts); | |
e7a3481c | 15 | void pvclock_resume(void); |
7af192c9 | 16 | |
347bb444 ZA |
17 | /* |
18 | * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction, | |
19 | * yielding a 64-bit result. | |
20 | */ | |
21 | static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift) | |
22 | { | |
23 | u64 product; | |
24 | #ifdef __i386__ | |
25 | u32 tmp1, tmp2; | |
de2d1a52 ZA |
26 | #else |
27 | ulong tmp; | |
347bb444 ZA |
28 | #endif |
29 | ||
30 | if (shift < 0) | |
31 | delta >>= -shift; | |
32 | else | |
33 | delta <<= shift; | |
34 | ||
35 | #ifdef __i386__ | |
36 | __asm__ ( | |
37 | "mul %5 ; " | |
38 | "mov %4,%%eax ; " | |
39 | "mov %%edx,%4 ; " | |
40 | "mul %5 ; " | |
41 | "xor %5,%5 ; " | |
42 | "add %4,%%eax ; " | |
43 | "adc %5,%%edx ; " | |
44 | : "=A" (product), "=r" (tmp1), "=r" (tmp2) | |
45 | : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) ); | |
46 | #elif defined(__x86_64__) | |
47 | __asm__ ( | |
3b217116 | 48 | "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]" |
de2d1a52 ZA |
49 | : [lo]"=a"(product), |
50 | [hi]"=d"(tmp) | |
51 | : "0"(delta), | |
52 | [mul_frac]"rm"((u64)mul_frac)); | |
347bb444 ZA |
53 | #else |
54 | #error implement me! | |
55 | #endif | |
56 | ||
57 | return product; | |
58 | } | |
59 | ||
dce2db0a MT |
60 | static __always_inline |
61 | u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src) | |
62 | { | |
63 | u64 delta = __native_read_tsc() - src->tsc_timestamp; | |
64 | return pvclock_scale_delta(delta, src->tsc_to_system_mul, | |
65 | src->tsc_shift); | |
66 | } | |
67 | ||
68 | static __always_inline | |
69 | unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, | |
70 | cycle_t *cycles, u8 *flags) | |
71 | { | |
72 | unsigned version; | |
73 | cycle_t ret, offset; | |
74 | u8 ret_flags; | |
75 | ||
76 | version = src->version; | |
189e1173 MT |
77 | /* Note: emulated platforms which do not advertise SSE2 support |
78 | * result in kvmclock not using the necessary RDTSC barriers. | |
79 | * Without barriers, it is possible that RDTSC instruction reads from | |
80 | * the time stamp counter outside rdtsc_barrier protected section | |
81 | * below, resulting in violation of monotonicity. | |
82 | */ | |
dce2db0a MT |
83 | rdtsc_barrier(); |
84 | offset = pvclock_get_nsec_offset(src); | |
85 | ret = src->system_time + offset; | |
86 | ret_flags = src->flags; | |
87 | rdtsc_barrier(); | |
88 | ||
89 | *cycles = ret; | |
90 | *flags = ret_flags; | |
91 | return version; | |
92 | } | |
93 | ||
71056ae2 MT |
94 | struct pvclock_vsyscall_time_info { |
95 | struct pvclock_vcpu_time_info pvti; | |
71056ae2 MT |
96 | } __attribute__((__aligned__(SMP_CACHE_BYTES))); |
97 | ||
98 | #define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info) | |
99 | #define PVCLOCK_VSYSCALL_NR_PAGES (((NR_CPUS-1)/(PAGE_SIZE/PVTI_SIZE))+1) | |
100 | ||
101 | int __init pvclock_init_vsyscall(struct pvclock_vsyscall_time_info *i, | |
102 | int size); | |
103 | struct pvclock_vcpu_time_info *pvclock_get_vsyscall_time_info(int cpu); | |
104 | ||
1965aae3 | 105 | #endif /* _ASM_X86_PVCLOCK_H */ |