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/* some helper functions for xen and kvm pv clock sources */
8cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
9u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
10void pvclock_set_flags(u8 flags);
11unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
12void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
13			    struct pvclock_vcpu_time_info *vcpu,
14			    struct timespec *ts);
15void pvclock_resume(void);
16
17void pvclock_touch_watchdogs(void);
18
19/*
20 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
21 * yielding a 64-bit result.
22 */
23static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
24{
25	u64 product;
26#ifdef __i386__
27	u32 tmp1, tmp2;
28#else
29	ulong tmp;
30#endif
31
32	if (shift < 0)
33		delta >>= -shift;
34	else
35		delta <<= shift;
36
37#ifdef __i386__
38	__asm__ (
39		"mul  %5       ; "
40		"mov  %4,%%eax ; "
41		"mov  %%edx,%4 ; "
42		"mul  %5       ; "
43		"xor  %5,%5    ; "
44		"add  %4,%%eax ; "
45		"adc  %5,%%edx ; "
46		: "=A" (product), "=r" (tmp1), "=r" (tmp2)
47		: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
48#elif defined(__x86_64__)
49	__asm__ (
50		"mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
51		: [lo]"=a"(product),
52		  [hi]"=d"(tmp)
53		: "0"(delta),
54		  [mul_frac]"rm"((u64)mul_frac));
55#else
56#error implement me!
57#endif
58
59	return product;
60}
61
62static __always_inline
63u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src)
64{
65	u64 delta = __native_read_tsc() - src->tsc_timestamp;
66	return pvclock_scale_delta(delta, src->tsc_to_system_mul,
67				   src->tsc_shift);
68}
69
70static __always_inline
71unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src,
72			       cycle_t *cycles, u8 *flags)
73{
74	unsigned version;
75	cycle_t ret, offset;
76	u8 ret_flags;
77
78	version = src->version;
79	/* Note: emulated platforms which do not advertise SSE2 support
80	 * result in kvmclock not using the necessary RDTSC barriers.
81	 * Without barriers, it is possible that RDTSC instruction reads from
82	 * the time stamp counter outside rdtsc_barrier protected section
83	 * below, resulting in violation of monotonicity.
84	 */
85	rdtsc_barrier();
86	offset = pvclock_get_nsec_offset(src);
87	ret = src->system_time + offset;
88	ret_flags = src->flags;
89	rdtsc_barrier();
90
91	*cycles = ret;
92	*flags = ret_flags;
93	return version;
94}
95
96struct pvclock_vsyscall_time_info {
97	struct pvclock_vcpu_time_info pvti;
98} __attribute__((__aligned__(SMP_CACHE_BYTES)));
99
100#define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
101#define PVCLOCK_VSYSCALL_NR_PAGES (((NR_CPUS-1)/(PAGE_SIZE/PVTI_SIZE))+1)
102
103int __init pvclock_init_vsyscall(struct pvclock_vsyscall_time_info *i,
104				 int size);
105struct pvclock_vcpu_time_info *pvclock_get_vsyscall_time_info(int cpu);
106
107#endif /* _ASM_X86_PVCLOCK_H */
108