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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright 2006 Andi Kleen, SUSE Labs.
4 *
5 * Fast user context implementation of clock_gettime, gettimeofday, and time.
6 *
7 * The code should have no internal unresolved relocations.
8 * Check with readelf after changing.
9 * Also alternative() doesn't work.
10 */
11/*
12 * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
13 */
14
15#include <linux/kernel.h>
16#include <linux/time.h>
17#include <linux/string.h>
18#include <asm/io.h>
19#include <asm/unistd.h>
20#include <asm/timex.h>
21#include <asm/clocksource.h>
22#include <asm/vvar.h>
23
24#ifdef CONFIG_SPARC64
25#define SYSCALL_STRING \
26 "ta 0x6d;" \
27 "bcs,a 1f;" \
28 " sub %%g0, %%o0, %%o0;" \
29 "1:"
30#else
31#define SYSCALL_STRING \
32 "ta 0x10;" \
33 "bcs,a 1f;" \
34 " sub %%g0, %%o0, %%o0;" \
35 "1:"
36#endif
37
38#define SYSCALL_CLOBBERS \
39 "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", \
40 "f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15", \
41 "f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23", \
42 "f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31", \
43 "f32", "f34", "f36", "f38", "f40", "f42", "f44", "f46", \
44 "f48", "f50", "f52", "f54", "f56", "f58", "f60", "f62", \
45 "cc", "memory"
46
47/*
48 * Compute the vvar page's address in the process address space, and return it
49 * as a pointer to the vvar_data.
50 */
51notrace static __always_inline struct vvar_data *get_vvar_data(void)
52{
53 unsigned long ret;
54
55 /*
56 * vdso data page is the first vDSO page so grab the PC
57 * and move up a page to get to the data page.
58 */
59 __asm__("rd %%pc, %0" : "=r" (ret));
60 ret &= ~(8192 - 1);
61 ret -= 8192;
62
63 return (struct vvar_data *) ret;
64}
65
66notrace static long vdso_fallback_gettime(long clock, struct __kernel_old_timespec *ts)
67{
68 register long num __asm__("g1") = __NR_clock_gettime;
69 register long o0 __asm__("o0") = clock;
70 register long o1 __asm__("o1") = (long) ts;
71
72 __asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num),
73 "0" (o0), "r" (o1) : SYSCALL_CLOBBERS);
74 return o0;
75}
76
77notrace static long vdso_fallback_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
78{
79 register long num __asm__("g1") = __NR_gettimeofday;
80 register long o0 __asm__("o0") = (long) tv;
81 register long o1 __asm__("o1") = (long) tz;
82
83 __asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num),
84 "0" (o0), "r" (o1) : SYSCALL_CLOBBERS);
85 return o0;
86}
87
88#ifdef CONFIG_SPARC64
89notrace static __always_inline u64 vread_tick(void)
90{
91 u64 ret;
92
93 __asm__ __volatile__("rd %%tick, %0" : "=r" (ret));
94 return ret;
95}
96
97notrace static __always_inline u64 vread_tick_stick(void)
98{
99 u64 ret;
100
101 __asm__ __volatile__("rd %%asr24, %0" : "=r" (ret));
102 return ret;
103}
104#else
105notrace static __always_inline u64 vread_tick(void)
106{
107 register unsigned long long ret asm("o4");
108
109 __asm__ __volatile__("rd %%tick, %L0\n\t"
110 "srlx %L0, 32, %H0"
111 : "=r" (ret));
112 return ret;
113}
114
115notrace static __always_inline u64 vread_tick_stick(void)
116{
117 register unsigned long long ret asm("o4");
118
119 __asm__ __volatile__("rd %%asr24, %L0\n\t"
120 "srlx %L0, 32, %H0"
121 : "=r" (ret));
122 return ret;
123}
124#endif
125
126notrace static __always_inline u64 vgetsns(struct vvar_data *vvar)
127{
128 u64 v;
129 u64 cycles;
130
131 cycles = vread_tick();
132 v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
133 return v * vvar->clock.mult;
134}
135
136notrace static __always_inline u64 vgetsns_stick(struct vvar_data *vvar)
137{
138 u64 v;
139 u64 cycles;
140
141 cycles = vread_tick_stick();
142 v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
143 return v * vvar->clock.mult;
144}
145
146notrace static __always_inline int do_realtime(struct vvar_data *vvar,
147 struct __kernel_old_timespec *ts)
148{
149 unsigned long seq;
150 u64 ns;
151
152 do {
153 seq = vvar_read_begin(vvar);
154 ts->tv_sec = vvar->wall_time_sec;
155 ns = vvar->wall_time_snsec;
156 ns += vgetsns(vvar);
157 ns >>= vvar->clock.shift;
158 } while (unlikely(vvar_read_retry(vvar, seq)));
159
160 ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
161 ts->tv_nsec = ns;
162
163 return 0;
164}
165
166notrace static __always_inline int do_realtime_stick(struct vvar_data *vvar,
167 struct __kernel_old_timespec *ts)
168{
169 unsigned long seq;
170 u64 ns;
171
172 do {
173 seq = vvar_read_begin(vvar);
174 ts->tv_sec = vvar->wall_time_sec;
175 ns = vvar->wall_time_snsec;
176 ns += vgetsns_stick(vvar);
177 ns >>= vvar->clock.shift;
178 } while (unlikely(vvar_read_retry(vvar, seq)));
179
180 ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
181 ts->tv_nsec = ns;
182
183 return 0;
184}
185
186notrace static __always_inline int do_monotonic(struct vvar_data *vvar,
187 struct __kernel_old_timespec *ts)
188{
189 unsigned long seq;
190 u64 ns;
191
192 do {
193 seq = vvar_read_begin(vvar);
194 ts->tv_sec = vvar->monotonic_time_sec;
195 ns = vvar->monotonic_time_snsec;
196 ns += vgetsns(vvar);
197 ns >>= vvar->clock.shift;
198 } while (unlikely(vvar_read_retry(vvar, seq)));
199
200 ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
201 ts->tv_nsec = ns;
202
203 return 0;
204}
205
206notrace static __always_inline int do_monotonic_stick(struct vvar_data *vvar,
207 struct __kernel_old_timespec *ts)
208{
209 unsigned long seq;
210 u64 ns;
211
212 do {
213 seq = vvar_read_begin(vvar);
214 ts->tv_sec = vvar->monotonic_time_sec;
215 ns = vvar->monotonic_time_snsec;
216 ns += vgetsns_stick(vvar);
217 ns >>= vvar->clock.shift;
218 } while (unlikely(vvar_read_retry(vvar, seq)));
219
220 ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
221 ts->tv_nsec = ns;
222
223 return 0;
224}
225
226notrace static int do_realtime_coarse(struct vvar_data *vvar,
227 struct __kernel_old_timespec *ts)
228{
229 unsigned long seq;
230
231 do {
232 seq = vvar_read_begin(vvar);
233 ts->tv_sec = vvar->wall_time_coarse_sec;
234 ts->tv_nsec = vvar->wall_time_coarse_nsec;
235 } while (unlikely(vvar_read_retry(vvar, seq)));
236 return 0;
237}
238
239notrace static int do_monotonic_coarse(struct vvar_data *vvar,
240 struct __kernel_old_timespec *ts)
241{
242 unsigned long seq;
243
244 do {
245 seq = vvar_read_begin(vvar);
246 ts->tv_sec = vvar->monotonic_time_coarse_sec;
247 ts->tv_nsec = vvar->monotonic_time_coarse_nsec;
248 } while (unlikely(vvar_read_retry(vvar, seq)));
249
250 return 0;
251}
252
253notrace int
254__vdso_clock_gettime(clockid_t clock, struct __kernel_old_timespec *ts)
255{
256 struct vvar_data *vvd = get_vvar_data();
257
258 switch (clock) {
259 case CLOCK_REALTIME:
260 if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
261 break;
262 return do_realtime(vvd, ts);
263 case CLOCK_MONOTONIC:
264 if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
265 break;
266 return do_monotonic(vvd, ts);
267 case CLOCK_REALTIME_COARSE:
268 return do_realtime_coarse(vvd, ts);
269 case CLOCK_MONOTONIC_COARSE:
270 return do_monotonic_coarse(vvd, ts);
271 }
272 /*
273 * Unknown clock ID ? Fall back to the syscall.
274 */
275 return vdso_fallback_gettime(clock, ts);
276}
277int
278clock_gettime(clockid_t, struct __kernel_old_timespec *)
279 __attribute__((weak, alias("__vdso_clock_gettime")));
280
281notrace int
282__vdso_clock_gettime_stick(clockid_t clock, struct __kernel_old_timespec *ts)
283{
284 struct vvar_data *vvd = get_vvar_data();
285
286 switch (clock) {
287 case CLOCK_REALTIME:
288 if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
289 break;
290 return do_realtime_stick(vvd, ts);
291 case CLOCK_MONOTONIC:
292 if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
293 break;
294 return do_monotonic_stick(vvd, ts);
295 case CLOCK_REALTIME_COARSE:
296 return do_realtime_coarse(vvd, ts);
297 case CLOCK_MONOTONIC_COARSE:
298 return do_monotonic_coarse(vvd, ts);
299 }
300 /*
301 * Unknown clock ID ? Fall back to the syscall.
302 */
303 return vdso_fallback_gettime(clock, ts);
304}
305
306notrace int
307__vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
308{
309 struct vvar_data *vvd = get_vvar_data();
310
311 if (likely(vvd->vclock_mode != VCLOCK_NONE)) {
312 if (likely(tv != NULL)) {
313 union tstv_t {
314 struct __kernel_old_timespec ts;
315 struct __kernel_old_timeval tv;
316 } *tstv = (union tstv_t *) tv;
317 do_realtime(vvd, &tstv->ts);
318 /*
319 * Assign before dividing to ensure that the division is
320 * done in the type of tv_usec, not tv_nsec.
321 *
322 * There cannot be > 1 billion usec in a second:
323 * do_realtime() has already distributed such overflow
324 * into tv_sec. So we can assign it to an int safely.
325 */
326 tstv->tv.tv_usec = tstv->ts.tv_nsec;
327 tstv->tv.tv_usec /= 1000;
328 }
329 if (unlikely(tz != NULL)) {
330 /* Avoid memcpy. Some old compilers fail to inline it */
331 tz->tz_minuteswest = vvd->tz_minuteswest;
332 tz->tz_dsttime = vvd->tz_dsttime;
333 }
334 return 0;
335 }
336 return vdso_fallback_gettimeofday(tv, tz);
337}
338int
339gettimeofday(struct __kernel_old_timeval *, struct timezone *)
340 __attribute__((weak, alias("__vdso_gettimeofday")));
341
342notrace int
343__vdso_gettimeofday_stick(struct __kernel_old_timeval *tv, struct timezone *tz)
344{
345 struct vvar_data *vvd = get_vvar_data();
346
347 if (likely(vvd->vclock_mode != VCLOCK_NONE)) {
348 if (likely(tv != NULL)) {
349 union tstv_t {
350 struct __kernel_old_timespec ts;
351 struct __kernel_old_timeval tv;
352 } *tstv = (union tstv_t *) tv;
353 do_realtime_stick(vvd, &tstv->ts);
354 /*
355 * Assign before dividing to ensure that the division is
356 * done in the type of tv_usec, not tv_nsec.
357 *
358 * There cannot be > 1 billion usec in a second:
359 * do_realtime() has already distributed such overflow
360 * into tv_sec. So we can assign it to an int safely.
361 */
362 tstv->tv.tv_usec = tstv->ts.tv_nsec;
363 tstv->tv.tv_usec /= 1000;
364 }
365 if (unlikely(tz != NULL)) {
366 /* Avoid memcpy. Some old compilers fail to inline it */
367 tz->tz_minuteswest = vvd->tz_minuteswest;
368 tz->tz_dsttime = vvd->tz_dsttime;
369 }
370 return 0;
371 }
372 return vdso_fallback_gettimeofday(tv, tz);
373}
1/*
2 * Copyright 2006 Andi Kleen, SUSE Labs.
3 * Subject to the GNU Public License, v.2
4 *
5 * Fast user context implementation of clock_gettime, gettimeofday, and time.
6 *
7 * The code should have no internal unresolved relocations.
8 * Check with readelf after changing.
9 * Also alternative() doesn't work.
10 */
11/*
12 * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
13 */
14
15/* Disable profiling for userspace code: */
16#ifndef DISABLE_BRANCH_PROFILING
17#define DISABLE_BRANCH_PROFILING
18#endif
19
20#include <linux/kernel.h>
21#include <linux/time.h>
22#include <linux/string.h>
23#include <asm/io.h>
24#include <asm/unistd.h>
25#include <asm/timex.h>
26#include <asm/clocksource.h>
27#include <asm/vvar.h>
28
29#undef TICK_PRIV_BIT
30#ifdef CONFIG_SPARC64
31#define TICK_PRIV_BIT (1UL << 63)
32#else
33#define TICK_PRIV_BIT (1ULL << 63)
34#endif
35
36#define SYSCALL_STRING \
37 "ta 0x6d;" \
38 "sub %%g0, %%o0, %%o0;" \
39
40#define SYSCALL_CLOBBERS \
41 "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", \
42 "f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15", \
43 "f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23", \
44 "f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31", \
45 "f32", "f34", "f36", "f38", "f40", "f42", "f44", "f46", \
46 "f48", "f50", "f52", "f54", "f56", "f58", "f60", "f62", \
47 "cc", "memory"
48
49/*
50 * Compute the vvar page's address in the process address space, and return it
51 * as a pointer to the vvar_data.
52 */
53static notrace noinline struct vvar_data *
54get_vvar_data(void)
55{
56 unsigned long ret;
57
58 /*
59 * vdso data page is the first vDSO page so grab the return address
60 * and move up a page to get to the data page.
61 */
62 ret = (unsigned long)__builtin_return_address(0);
63 ret &= ~(8192 - 1);
64 ret -= 8192;
65
66 return (struct vvar_data *) ret;
67}
68
69static notrace long
70vdso_fallback_gettime(long clock, struct timespec *ts)
71{
72 register long num __asm__("g1") = __NR_clock_gettime;
73 register long o0 __asm__("o0") = clock;
74 register long o1 __asm__("o1") = (long) ts;
75
76 __asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num),
77 "0" (o0), "r" (o1) : SYSCALL_CLOBBERS);
78 return o0;
79}
80
81static notrace __always_inline long
82vdso_fallback_gettimeofday(struct timeval *tv, struct timezone *tz)
83{
84 register long num __asm__("g1") = __NR_gettimeofday;
85 register long o0 __asm__("o0") = (long) tv;
86 register long o1 __asm__("o1") = (long) tz;
87
88 __asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num),
89 "0" (o0), "r" (o1) : SYSCALL_CLOBBERS);
90 return o0;
91}
92
93#ifdef CONFIG_SPARC64
94static notrace noinline u64
95vread_tick(void) {
96 u64 ret;
97
98 __asm__ __volatile__("rd %%asr24, %0 \n"
99 ".section .vread_tick_patch, \"ax\" \n"
100 "rd %%tick, %0 \n"
101 ".previous \n"
102 : "=&r" (ret));
103 return ret & ~TICK_PRIV_BIT;
104}
105#else
106static notrace noinline u64
107vread_tick(void)
108{
109 unsigned int lo, hi;
110
111 __asm__ __volatile__("rd %%asr24, %%g1\n\t"
112 "srlx %%g1, 32, %1\n\t"
113 "srl %%g1, 0, %0\n"
114 ".section .vread_tick_patch, \"ax\" \n"
115 "rd %%tick, %%g1\n"
116 ".previous \n"
117 : "=&r" (lo), "=&r" (hi)
118 :
119 : "g1");
120 return lo | ((u64)hi << 32);
121}
122#endif
123
124static notrace inline u64
125vgetsns(struct vvar_data *vvar)
126{
127 u64 v;
128 u64 cycles;
129
130 cycles = vread_tick();
131 v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
132 return v * vvar->clock.mult;
133}
134
135static notrace noinline int
136do_realtime(struct vvar_data *vvar, struct timespec *ts)
137{
138 unsigned long seq;
139 u64 ns;
140
141 ts->tv_nsec = 0;
142 do {
143 seq = vvar_read_begin(vvar);
144 ts->tv_sec = vvar->wall_time_sec;
145 ns = vvar->wall_time_snsec;
146 ns += vgetsns(vvar);
147 ns >>= vvar->clock.shift;
148 } while (unlikely(vvar_read_retry(vvar, seq)));
149
150 timespec_add_ns(ts, ns);
151
152 return 0;
153}
154
155static notrace noinline int
156do_monotonic(struct vvar_data *vvar, struct timespec *ts)
157{
158 unsigned long seq;
159 u64 ns;
160
161 ts->tv_nsec = 0;
162 do {
163 seq = vvar_read_begin(vvar);
164 ts->tv_sec = vvar->monotonic_time_sec;
165 ns = vvar->monotonic_time_snsec;
166 ns += vgetsns(vvar);
167 ns >>= vvar->clock.shift;
168 } while (unlikely(vvar_read_retry(vvar, seq)));
169
170 timespec_add_ns(ts, ns);
171
172 return 0;
173}
174
175static notrace noinline int
176do_realtime_coarse(struct vvar_data *vvar, struct timespec *ts)
177{
178 unsigned long seq;
179
180 do {
181 seq = vvar_read_begin(vvar);
182 ts->tv_sec = vvar->wall_time_coarse_sec;
183 ts->tv_nsec = vvar->wall_time_coarse_nsec;
184 } while (unlikely(vvar_read_retry(vvar, seq)));
185 return 0;
186}
187
188static notrace noinline int
189do_monotonic_coarse(struct vvar_data *vvar, struct timespec *ts)
190{
191 unsigned long seq;
192
193 do {
194 seq = vvar_read_begin(vvar);
195 ts->tv_sec = vvar->monotonic_time_coarse_sec;
196 ts->tv_nsec = vvar->monotonic_time_coarse_nsec;
197 } while (unlikely(vvar_read_retry(vvar, seq)));
198
199 return 0;
200}
201
202notrace int
203__vdso_clock_gettime(clockid_t clock, struct timespec *ts)
204{
205 struct vvar_data *vvd = get_vvar_data();
206
207 switch (clock) {
208 case CLOCK_REALTIME:
209 if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
210 break;
211 return do_realtime(vvd, ts);
212 case CLOCK_MONOTONIC:
213 if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
214 break;
215 return do_monotonic(vvd, ts);
216 case CLOCK_REALTIME_COARSE:
217 return do_realtime_coarse(vvd, ts);
218 case CLOCK_MONOTONIC_COARSE:
219 return do_monotonic_coarse(vvd, ts);
220 }
221 /*
222 * Unknown clock ID ? Fall back to the syscall.
223 */
224 return vdso_fallback_gettime(clock, ts);
225}
226int
227clock_gettime(clockid_t, struct timespec *)
228 __attribute__((weak, alias("__vdso_clock_gettime")));
229
230notrace int
231__vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
232{
233 struct vvar_data *vvd = get_vvar_data();
234
235 if (likely(vvd->vclock_mode != VCLOCK_NONE)) {
236 if (likely(tv != NULL)) {
237 union tstv_t {
238 struct timespec ts;
239 struct timeval tv;
240 } *tstv = (union tstv_t *) tv;
241 do_realtime(vvd, &tstv->ts);
242 /*
243 * Assign before dividing to ensure that the division is
244 * done in the type of tv_usec, not tv_nsec.
245 *
246 * There cannot be > 1 billion usec in a second:
247 * do_realtime() has already distributed such overflow
248 * into tv_sec. So we can assign it to an int safely.
249 */
250 tstv->tv.tv_usec = tstv->ts.tv_nsec;
251 tstv->tv.tv_usec /= 1000;
252 }
253 if (unlikely(tz != NULL)) {
254 /* Avoid memcpy. Some old compilers fail to inline it */
255 tz->tz_minuteswest = vvd->tz_minuteswest;
256 tz->tz_dsttime = vvd->tz_dsttime;
257 }
258 return 0;
259 }
260 return vdso_fallback_gettimeofday(tv, tz);
261}
262int
263gettimeofday(struct timeval *, struct timezone *)
264 __attribute__((weak, alias("__vdso_gettimeofday")));