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
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
|
/*
* Copyright 2015 Mentor Graphics Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/compiler.h>
#include <linux/hrtimer.h>
#include <linux/time.h>
#include <asm/barrier.h>
#include <asm/bug.h>
#include <asm/cp15.h>
#include <asm/page.h>
#include <asm/unistd.h>
#include <asm/vdso_datapage.h>
#ifndef CONFIG_AEABI
#error This code depends on AEABI system call conventions
#endif
extern struct vdso_data *__get_datapage(void);
static notrace u32 __vdso_read_begin(const struct vdso_data *vdata)
{
u32 seq;
repeat:
seq = READ_ONCE(vdata->seq_count);
if (seq & 1) {
cpu_relax();
goto repeat;
}
return seq;
}
static notrace u32 vdso_read_begin(const struct vdso_data *vdata)
{
u32 seq;
seq = __vdso_read_begin(vdata);
smp_rmb(); /* Pairs with smp_wmb in vdso_write_end */
return seq;
}
static notrace int vdso_read_retry(const struct vdso_data *vdata, u32 start)
{
smp_rmb(); /* Pairs with smp_wmb in vdso_write_begin */
return vdata->seq_count != start;
}
static notrace long clock_gettime_fallback(clockid_t _clkid,
struct timespec *_ts)
{
register struct timespec *ts asm("r1") = _ts;
register clockid_t clkid asm("r0") = _clkid;
register long ret asm ("r0");
register long nr asm("r7") = __NR_clock_gettime;
asm volatile(
" swi #0\n"
: "=r" (ret)
: "r" (clkid), "r" (ts), "r" (nr)
: "memory");
return ret;
}
static notrace int do_realtime_coarse(struct timespec *ts,
struct vdso_data *vdata)
{
u32 seq;
do {
seq = vdso_read_begin(vdata);
ts->tv_sec = vdata->xtime_coarse_sec;
ts->tv_nsec = vdata->xtime_coarse_nsec;
} while (vdso_read_retry(vdata, seq));
return 0;
}
static notrace int do_monotonic_coarse(struct timespec *ts,
struct vdso_data *vdata)
{
struct timespec tomono;
u32 seq;
do {
seq = vdso_read_begin(vdata);
ts->tv_sec = vdata->xtime_coarse_sec;
ts->tv_nsec = vdata->xtime_coarse_nsec;
tomono.tv_sec = vdata->wtm_clock_sec;
tomono.tv_nsec = vdata->wtm_clock_nsec;
} while (vdso_read_retry(vdata, seq));
ts->tv_sec += tomono.tv_sec;
timespec_add_ns(ts, tomono.tv_nsec);
return 0;
}
#ifdef CONFIG_ARM_ARCH_TIMER
static notrace u64 get_ns(struct vdso_data *vdata)
{
u64 cycle_delta;
u64 cycle_now;
u64 nsec;
isb();
cycle_now = read_sysreg(CNTVCT);
cycle_delta = (cycle_now - vdata->cs_cycle_last) & vdata->cs_mask;
nsec = (cycle_delta * vdata->cs_mult) + vdata->xtime_clock_snsec;
nsec >>= vdata->cs_shift;
return nsec;
}
static notrace int do_realtime(struct timespec *ts, struct vdso_data *vdata)
{
u64 nsecs;
u32 seq;
do {
seq = vdso_read_begin(vdata);
if (!vdata->tk_is_cntvct)
return -1;
ts->tv_sec = vdata->xtime_clock_sec;
nsecs = get_ns(vdata);
} while (vdso_read_retry(vdata, seq));
ts->tv_nsec = 0;
timespec_add_ns(ts, nsecs);
return 0;
}
static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata)
{
struct timespec tomono;
u64 nsecs;
u32 seq;
do {
seq = vdso_read_begin(vdata);
if (!vdata->tk_is_cntvct)
return -1;
ts->tv_sec = vdata->xtime_clock_sec;
nsecs = get_ns(vdata);
tomono.tv_sec = vdata->wtm_clock_sec;
tomono.tv_nsec = vdata->wtm_clock_nsec;
} while (vdso_read_retry(vdata, seq));
ts->tv_sec += tomono.tv_sec;
ts->tv_nsec = 0;
timespec_add_ns(ts, nsecs + tomono.tv_nsec);
return 0;
}
#else /* CONFIG_ARM_ARCH_TIMER */
static notrace int do_realtime(struct timespec *ts, struct vdso_data *vdata)
{
return -1;
}
static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata)
{
return -1;
}
#endif /* CONFIG_ARM_ARCH_TIMER */
notrace int __vdso_clock_gettime(clockid_t clkid, struct timespec *ts)
{
struct vdso_data *vdata;
int ret = -1;
vdata = __get_datapage();
switch (clkid) {
case CLOCK_REALTIME_COARSE:
ret = do_realtime_coarse(ts, vdata);
break;
case CLOCK_MONOTONIC_COARSE:
ret = do_monotonic_coarse(ts, vdata);
break;
case CLOCK_REALTIME:
ret = do_realtime(ts, vdata);
break;
case CLOCK_MONOTONIC:
ret = do_monotonic(ts, vdata);
break;
default:
break;
}
if (ret)
ret = clock_gettime_fallback(clkid, ts);
return ret;
}
static notrace long gettimeofday_fallback(struct timeval *_tv,
struct timezone *_tz)
{
register struct timezone *tz asm("r1") = _tz;
register struct timeval *tv asm("r0") = _tv;
register long ret asm ("r0");
register long nr asm("r7") = __NR_gettimeofday;
asm volatile(
" swi #0\n"
: "=r" (ret)
: "r" (tv), "r" (tz), "r" (nr)
: "memory");
return ret;
}
notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
{
struct timespec ts;
struct vdso_data *vdata;
int ret;
vdata = __get_datapage();
ret = do_realtime(&ts, vdata);
if (ret)
return gettimeofday_fallback(tv, tz);
if (tv) {
tv->tv_sec = ts.tv_sec;
tv->tv_usec = ts.tv_nsec / 1000;
}
if (tz) {
tz->tz_minuteswest = vdata->tz_minuteswest;
tz->tz_dsttime = vdata->tz_dsttime;
}
return ret;
}
/* Avoid unresolved references emitted by GCC */
void __aeabi_unwind_cpp_pr0(void)
{
}
void __aeabi_unwind_cpp_pr1(void)
{
}
void __aeabi_unwind_cpp_pr2(void)
{
}
|
