1/*-
2 * Copyright (c) 2014, Bryan Venteicher <bryanv@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#ifndef X86_PVCLOCK
28#define X86_PVCLOCK
29
30#include <sys/types.h>
31
32#ifdef _KERNEL
33#include <sys/timetc.h>
34#endif /* _KERNEL */
35
36#define PVCLOCK_CDEVNAME "pvclock"
37
38struct pvclock_vcpu_time_info {
39 uint32_t version;
40 uint32_t pad0;
41 uint64_t tsc_timestamp;
42 uint64_t system_time;
43 uint32_t tsc_to_system_mul;
44 int8_t tsc_shift;
45 uint8_t flags;
46 uint8_t pad[2];
47};
48
49#define PVCLOCK_FLAG_TSC_STABLE 0x01
50#define PVCLOCK_FLAG_GUEST_PASUED 0x02
51
52/*
53 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
54 * yielding a 64-bit result.
55 */
56static inline uint64_t
57pvclock_scale_delta(uint64_t delta, uint32_t mul_frac, int shift)
58{
59 uint64_t product;
60
61 if (shift < 0)
62 delta >>= -shift;
63 else
64 delta <<= shift;
65#if defined(__i386__)
66 {
67 uint32_t tmp1, tmp2;
68
69 /**
70 * For i386, the formula looks like:
71 *
72 * lower = (mul_frac * (delta & UINT_MAX)) >> 32
73 * upper = mul_frac * (delta >> 32)
74 * product = lower + upper
75 */
76 __asm__ (
77 "mul %5 ; "
78 "mov %4,%%eax ; "
79 "mov %%edx,%4 ; "
80 "mul %5 ; "
81 "xor %5,%5 ; "
82 "add %4,%%eax ; "
83 "adc %5,%%edx ; "
84 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
85 : "a" ((uint32_t)delta), "1" ((uint32_t)(delta >> 32)),
86 "2" (mul_frac) );
87 }
88#elif defined(__amd64__)
89 {
90 unsigned long tmp;
91
92 __asm__ (
93 "mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
94 : [lo]"=a" (product), [hi]"=d" (tmp)
95 : "0" (delta), [mul_frac]"rm"((uint64_t)mul_frac));
96 }
97#else
98#error "pvclock: unsupported x86 architecture?"
99#endif
100 return (product);
101}
102
103#ifdef _KERNEL
104
105typedef struct pvclock_wall_clock *pvclock_get_wallclock_t(void *arg);
106
107struct pvclock_wall_clock {
108 uint32_t version;
109 uint32_t sec;
110 uint32_t nsec;
111};
112
113struct pvclock {
114 /* Public; initialized by the caller of 'pvclock_init()': */
115 pvclock_get_wallclock_t *get_wallclock;
116 void *get_wallclock_arg;
117 struct pvclock_vcpu_time_info *timeinfos;
118 bool stable_flag_supported;
119
120 /* Private; initialized by the 'pvclock' API: */
121 bool vdso_force_unstable;
122 bool vdso_enable_without_rdtscp;
123 struct timecounter tc;
124 struct cdev *cdev;
125};
126
127/*
128 * NOTE: 'pvclock_get_timecount()' and 'pvclock_get_wallclock()' are purely
129 * transitional; they should be removed after 'dev/xen/timer/timer.c' has been
130 * migrated to the 'struct pvclock' API.
131 */
132void pvclock_resume(void);
133uint64_t pvclock_tsc_freq(struct pvclock_vcpu_time_info *ti);
134uint64_t pvclock_get_timecount(struct pvclock_vcpu_time_info *ti);
135void pvclock_get_wallclock(struct pvclock_wall_clock *wc,
136 struct timespec *ts);
137
138void pvclock_init(struct pvclock *pvc, device_t dev,
139 const char *tc_name, int tc_quality, u_int tc_flags);
140void pvclock_gettime(struct pvclock *pvc, struct timespec *ts);
141int pvclock_destroy(struct pvclock *pvc);
142
143#endif /* _KERNEL */
144
145#endif