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7c97f91e MM |
1 | /* Linux-dependent part of branch trace support for GDB, and GDBserver. |
2 | ||
32d0add0 | 3 | Copyright (C) 2013-2015 Free Software Foundation, Inc. |
7c97f91e MM |
4 | |
5 | Contributed by Intel Corp. <markus.t.metzger@intel.com> | |
6 | ||
7 | This file is part of GDB. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 3 of the License, or | |
12 | (at your option) any later version. | |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
21 | ||
53f81362 | 22 | #include "common-defs.h" |
7c97f91e | 23 | #include "linux-btrace.h" |
361c8ade | 24 | #include "common-regcache.h" |
be8b1ea6 | 25 | #include "gdb_wait.h" |
df7e5265 | 26 | #include "x86-cpuid.h" |
7c97f91e | 27 | |
5b4e221c MF |
28 | #ifdef HAVE_SYS_SYSCALL_H |
29 | #include <sys/syscall.h> | |
30 | #endif | |
31 | ||
32 | #if HAVE_LINUX_PERF_EVENT_H && defined(SYS_perf_event_open) | |
7c97f91e | 33 | |
7c97f91e MM |
34 | #include <stdint.h> |
35 | #include <unistd.h> | |
7c97f91e MM |
36 | #include <sys/mman.h> |
37 | #include <sys/user.h> | |
a950d57c MM |
38 | #include <sys/ptrace.h> |
39 | #include <sys/types.h> | |
a950d57c | 40 | #include <signal.h> |
7c97f91e MM |
41 | |
42 | /* A branch trace record in perf_event. */ | |
43 | struct perf_event_bts | |
44 | { | |
45 | /* The linear address of the branch source. */ | |
46 | uint64_t from; | |
47 | ||
48 | /* The linear address of the branch destination. */ | |
49 | uint64_t to; | |
50 | }; | |
51 | ||
52 | /* A perf_event branch trace sample. */ | |
53 | struct perf_event_sample | |
54 | { | |
55 | /* The perf_event sample header. */ | |
56 | struct perf_event_header header; | |
57 | ||
58 | /* The perf_event branch tracing payload. */ | |
59 | struct perf_event_bts bts; | |
60 | }; | |
61 | ||
62 | /* Get the perf_event header. */ | |
63 | ||
64 | static inline volatile struct perf_event_mmap_page * | |
65 | perf_event_header (struct btrace_target_info* tinfo) | |
66 | { | |
67 | return tinfo->buffer; | |
68 | } | |
69 | ||
70 | /* Get the size of the perf_event mmap buffer. */ | |
71 | ||
72 | static inline size_t | |
73 | perf_event_mmap_size (const struct btrace_target_info *tinfo) | |
74 | { | |
75 | /* The branch trace buffer is preceded by a configuration page. */ | |
76 | return (tinfo->size + 1) * PAGE_SIZE; | |
77 | } | |
78 | ||
79 | /* Get the size of the perf_event buffer. */ | |
80 | ||
81 | static inline size_t | |
82 | perf_event_buffer_size (struct btrace_target_info* tinfo) | |
83 | { | |
84 | return tinfo->size * PAGE_SIZE; | |
85 | } | |
86 | ||
87 | /* Get the start address of the perf_event buffer. */ | |
88 | ||
89 | static inline const uint8_t * | |
90 | perf_event_buffer_begin (struct btrace_target_info* tinfo) | |
91 | { | |
92 | return ((const uint8_t *) tinfo->buffer) + PAGE_SIZE; | |
93 | } | |
94 | ||
95 | /* Get the end address of the perf_event buffer. */ | |
96 | ||
97 | static inline const uint8_t * | |
98 | perf_event_buffer_end (struct btrace_target_info* tinfo) | |
99 | { | |
100 | return perf_event_buffer_begin (tinfo) + perf_event_buffer_size (tinfo); | |
101 | } | |
102 | ||
103 | /* Check whether an address is in the kernel. */ | |
104 | ||
105 | static inline int | |
106 | perf_event_is_kernel_addr (const struct btrace_target_info *tinfo, | |
107 | uint64_t addr) | |
108 | { | |
109 | uint64_t mask; | |
110 | ||
111 | /* If we don't know the size of a pointer, we can't check. Let's assume it's | |
112 | not a kernel address in this case. */ | |
113 | if (tinfo->ptr_bits == 0) | |
114 | return 0; | |
115 | ||
116 | /* A bit mask for the most significant bit in an address. */ | |
117 | mask = (uint64_t) 1 << (tinfo->ptr_bits - 1); | |
118 | ||
119 | /* Check whether the most significant bit in the address is set. */ | |
120 | return (addr & mask) != 0; | |
121 | } | |
122 | ||
123 | /* Check whether a perf event record should be skipped. */ | |
124 | ||
125 | static inline int | |
126 | perf_event_skip_record (const struct btrace_target_info *tinfo, | |
127 | const struct perf_event_bts *bts) | |
128 | { | |
129 | /* The hardware may report branches from kernel into user space. Branches | |
130 | from user into kernel space will be suppressed. We filter the former to | |
131 | provide a consistent branch trace excluding kernel. */ | |
132 | return perf_event_is_kernel_addr (tinfo, bts->from); | |
133 | } | |
134 | ||
135 | /* Perform a few consistency checks on a perf event sample record. This is | |
136 | meant to catch cases when we get out of sync with the perf event stream. */ | |
137 | ||
138 | static inline int | |
139 | perf_event_sample_ok (const struct perf_event_sample *sample) | |
140 | { | |
141 | if (sample->header.type != PERF_RECORD_SAMPLE) | |
142 | return 0; | |
143 | ||
144 | if (sample->header.size != sizeof (*sample)) | |
145 | return 0; | |
146 | ||
147 | return 1; | |
148 | } | |
149 | ||
150 | /* Branch trace is collected in a circular buffer [begin; end) as pairs of from | |
151 | and to addresses (plus a header). | |
152 | ||
153 | Start points into that buffer at the next sample position. | |
154 | We read the collected samples backwards from start. | |
155 | ||
156 | While reading the samples, we convert the information into a list of blocks. | |
157 | For two adjacent samples s1 and s2, we form a block b such that b.begin = | |
158 | s1.to and b.end = s2.from. | |
159 | ||
160 | In case the buffer overflows during sampling, one sample may have its lower | |
161 | part at the end and its upper part at the beginning of the buffer. */ | |
162 | ||
163 | static VEC (btrace_block_s) * | |
164 | perf_event_read_bts (struct btrace_target_info* tinfo, const uint8_t *begin, | |
969c39fb | 165 | const uint8_t *end, const uint8_t *start, size_t size) |
7c97f91e MM |
166 | { |
167 | VEC (btrace_block_s) *btrace = NULL; | |
168 | struct perf_event_sample sample; | |
969c39fb | 169 | size_t read = 0; |
7c97f91e MM |
170 | struct btrace_block block = { 0, 0 }; |
171 | struct regcache *regcache; | |
172 | ||
173 | gdb_assert (begin <= start); | |
174 | gdb_assert (start <= end); | |
175 | ||
176 | /* The first block ends at the current pc. */ | |
361c8ade | 177 | regcache = get_thread_regcache_for_ptid (tinfo->ptid); |
7c97f91e MM |
178 | block.end = regcache_read_pc (regcache); |
179 | ||
180 | /* The buffer may contain a partial record as its last entry (i.e. when the | |
181 | buffer size is not a multiple of the sample size). */ | |
182 | read = sizeof (sample) - 1; | |
183 | ||
184 | for (; read < size; read += sizeof (sample)) | |
185 | { | |
186 | const struct perf_event_sample *psample; | |
187 | ||
188 | /* Find the next perf_event sample in a backwards traversal. */ | |
189 | start -= sizeof (sample); | |
190 | ||
191 | /* If we're still inside the buffer, we're done. */ | |
192 | if (begin <= start) | |
193 | psample = (const struct perf_event_sample *) start; | |
194 | else | |
195 | { | |
196 | int missing; | |
197 | ||
198 | /* We're to the left of the ring buffer, we will wrap around and | |
199 | reappear at the very right of the ring buffer. */ | |
200 | ||
201 | missing = (begin - start); | |
202 | start = (end - missing); | |
203 | ||
204 | /* If the entire sample is missing, we're done. */ | |
205 | if (missing == sizeof (sample)) | |
206 | psample = (const struct perf_event_sample *) start; | |
207 | else | |
208 | { | |
209 | uint8_t *stack; | |
210 | ||
211 | /* The sample wrapped around. The lower part is at the end and | |
212 | the upper part is at the beginning of the buffer. */ | |
213 | stack = (uint8_t *) &sample; | |
214 | ||
215 | /* Copy the two parts so we have a contiguous sample. */ | |
216 | memcpy (stack, start, missing); | |
217 | memcpy (stack + missing, begin, sizeof (sample) - missing); | |
218 | ||
219 | psample = &sample; | |
220 | } | |
221 | } | |
222 | ||
223 | if (!perf_event_sample_ok (psample)) | |
224 | { | |
225 | warning (_("Branch trace may be incomplete.")); | |
226 | break; | |
227 | } | |
228 | ||
229 | if (perf_event_skip_record (tinfo, &psample->bts)) | |
230 | continue; | |
231 | ||
232 | /* We found a valid sample, so we can complete the current block. */ | |
233 | block.begin = psample->bts.to; | |
234 | ||
235 | VEC_safe_push (btrace_block_s, btrace, &block); | |
236 | ||
237 | /* Start the next block. */ | |
238 | block.end = psample->bts.from; | |
239 | } | |
240 | ||
969c39fb MM |
241 | /* Push the last block (i.e. the first one of inferior execution), as well. |
242 | We don't know where it ends, but we know where it starts. If we're | |
243 | reading delta trace, we can fill in the start address later on. | |
244 | Otherwise we will prune it. */ | |
245 | block.begin = 0; | |
246 | VEC_safe_push (btrace_block_s, btrace, &block); | |
247 | ||
7c97f91e MM |
248 | return btrace; |
249 | } | |
250 | ||
a950d57c MM |
251 | /* Check whether the kernel supports branch tracing. */ |
252 | ||
253 | static int | |
254 | kernel_supports_btrace (void) | |
255 | { | |
256 | struct perf_event_attr attr; | |
257 | pid_t child, pid; | |
258 | int status, file; | |
259 | ||
260 | errno = 0; | |
261 | child = fork (); | |
262 | switch (child) | |
263 | { | |
264 | case -1: | |
265 | warning (_("test branch tracing: cannot fork: %s."), strerror (errno)); | |
266 | return 0; | |
267 | ||
268 | case 0: | |
269 | status = ptrace (PTRACE_TRACEME, 0, NULL, NULL); | |
270 | if (status != 0) | |
271 | { | |
272 | warning (_("test branch tracing: cannot PTRACE_TRACEME: %s."), | |
273 | strerror (errno)); | |
274 | _exit (1); | |
275 | } | |
276 | ||
277 | status = raise (SIGTRAP); | |
278 | if (status != 0) | |
279 | { | |
280 | warning (_("test branch tracing: cannot raise SIGTRAP: %s."), | |
281 | strerror (errno)); | |
282 | _exit (1); | |
283 | } | |
284 | ||
285 | _exit (1); | |
286 | ||
287 | default: | |
288 | pid = waitpid (child, &status, 0); | |
289 | if (pid != child) | |
290 | { | |
291 | warning (_("test branch tracing: bad pid %ld, error: %s."), | |
292 | (long) pid, strerror (errno)); | |
293 | return 0; | |
294 | } | |
295 | ||
296 | if (!WIFSTOPPED (status)) | |
297 | { | |
298 | warning (_("test branch tracing: expected stop. status: %d."), | |
299 | status); | |
300 | return 0; | |
301 | } | |
302 | ||
303 | memset (&attr, 0, sizeof (attr)); | |
304 | ||
305 | attr.type = PERF_TYPE_HARDWARE; | |
306 | attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS; | |
307 | attr.sample_period = 1; | |
308 | attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR; | |
309 | attr.exclude_kernel = 1; | |
310 | attr.exclude_hv = 1; | |
311 | attr.exclude_idle = 1; | |
312 | ||
313 | file = syscall (SYS_perf_event_open, &attr, child, -1, -1, 0); | |
314 | if (file >= 0) | |
315 | close (file); | |
316 | ||
317 | kill (child, SIGKILL); | |
318 | ptrace (PTRACE_KILL, child, NULL, NULL); | |
319 | ||
320 | pid = waitpid (child, &status, 0); | |
321 | if (pid != child) | |
322 | { | |
323 | warning (_("test branch tracing: bad pid %ld, error: %s."), | |
324 | (long) pid, strerror (errno)); | |
325 | if (!WIFSIGNALED (status)) | |
326 | warning (_("test branch tracing: expected killed. status: %d."), | |
327 | status); | |
328 | } | |
329 | ||
330 | return (file >= 0); | |
331 | } | |
332 | } | |
333 | ||
334 | /* Check whether an Intel cpu supports branch tracing. */ | |
335 | ||
336 | static int | |
337 | intel_supports_btrace (void) | |
338 | { | |
5f8e0b8f MF |
339 | unsigned int cpuid, model, family; |
340 | ||
df7e5265 | 341 | if (!x86_cpuid (1, &cpuid, NULL, NULL, NULL)) |
4d157a3d | 342 | return 0; |
5f8e0b8f MF |
343 | |
344 | family = (cpuid >> 8) & 0xf; | |
345 | model = (cpuid >> 4) & 0xf; | |
346 | ||
347 | switch (family) | |
348 | { | |
349 | case 0x6: | |
350 | model += (cpuid >> 12) & 0xf0; | |
351 | ||
352 | switch (model) | |
353 | { | |
354 | case 0x1a: /* Nehalem */ | |
355 | case 0x1f: | |
356 | case 0x1e: | |
357 | case 0x2e: | |
358 | case 0x25: /* Westmere */ | |
359 | case 0x2c: | |
360 | case 0x2f: | |
361 | case 0x2a: /* Sandy Bridge */ | |
362 | case 0x2d: | |
363 | case 0x3a: /* Ivy Bridge */ | |
364 | ||
365 | /* AAJ122: LBR, BTM, or BTS records may have incorrect branch | |
366 | "from" information afer an EIST transition, T-states, C1E, or | |
367 | Adaptive Thermal Throttling. */ | |
368 | return 0; | |
369 | } | |
370 | } | |
a950d57c MM |
371 | |
372 | return 1; | |
a950d57c MM |
373 | } |
374 | ||
375 | /* Check whether the cpu supports branch tracing. */ | |
376 | ||
377 | static int | |
378 | cpu_supports_btrace (void) | |
379 | { | |
4d157a3d | 380 | unsigned int ebx, ecx, edx; |
a950d57c | 381 | |
df7e5265 | 382 | if (!x86_cpuid (0, NULL, &ebx, &ecx, &edx)) |
4d157a3d MF |
383 | return 0; |
384 | ||
4353c9e6 JK |
385 | if (ebx == signature_INTEL_ebx && ecx == signature_INTEL_ecx |
386 | && edx == signature_INTEL_edx) | |
a950d57c MM |
387 | return intel_supports_btrace (); |
388 | ||
389 | /* Don't know about others. Let's assume they do. */ | |
390 | return 1; | |
a950d57c MM |
391 | } |
392 | ||
7c97f91e MM |
393 | /* See linux-btrace.h. */ |
394 | ||
395 | int | |
46917d26 | 396 | linux_supports_btrace (struct target_ops *ops) |
7c97f91e | 397 | { |
a950d57c MM |
398 | static int cached; |
399 | ||
400 | if (cached == 0) | |
401 | { | |
402 | if (!kernel_supports_btrace ()) | |
403 | cached = -1; | |
404 | else if (!cpu_supports_btrace ()) | |
405 | cached = -1; | |
406 | else | |
407 | cached = 1; | |
408 | } | |
409 | ||
410 | return cached > 0; | |
7c97f91e MM |
411 | } |
412 | ||
413 | /* See linux-btrace.h. */ | |
414 | ||
415 | struct btrace_target_info * | |
416 | linux_enable_btrace (ptid_t ptid) | |
417 | { | |
418 | struct btrace_target_info *tinfo; | |
d0fa7535 | 419 | int pid, pg; |
7c97f91e MM |
420 | |
421 | tinfo = xzalloc (sizeof (*tinfo)); | |
422 | tinfo->ptid = ptid; | |
423 | ||
424 | tinfo->attr.size = sizeof (tinfo->attr); | |
425 | tinfo->attr.type = PERF_TYPE_HARDWARE; | |
426 | tinfo->attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS; | |
427 | tinfo->attr.sample_period = 1; | |
428 | ||
429 | /* We sample from and to address. */ | |
430 | tinfo->attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR; | |
431 | ||
432 | tinfo->attr.exclude_kernel = 1; | |
433 | tinfo->attr.exclude_hv = 1; | |
434 | tinfo->attr.exclude_idle = 1; | |
435 | ||
436 | tinfo->ptr_bits = 0; | |
437 | ||
438 | pid = ptid_get_lwp (ptid); | |
439 | if (pid == 0) | |
440 | pid = ptid_get_pid (ptid); | |
441 | ||
442 | errno = 0; | |
443 | tinfo->file = syscall (SYS_perf_event_open, &tinfo->attr, pid, -1, -1, 0); | |
444 | if (tinfo->file < 0) | |
445 | goto err; | |
446 | ||
d0fa7535 MM |
447 | /* We try to allocate as much buffer as we can get. |
448 | We could allow the user to specify the size of the buffer, but then | |
449 | we'd leave this search for the maximum buffer size to him. */ | |
450 | for (pg = 4; pg >= 0; --pg) | |
451 | { | |
452 | /* The number of pages we request needs to be a power of two. */ | |
453 | tinfo->size = 1 << pg; | |
454 | tinfo->buffer = mmap (NULL, perf_event_mmap_size (tinfo), | |
455 | PROT_READ, MAP_SHARED, tinfo->file, 0); | |
456 | if (tinfo->buffer == MAP_FAILED) | |
457 | continue; | |
7c97f91e | 458 | |
d0fa7535 MM |
459 | return tinfo; |
460 | } | |
7c97f91e | 461 | |
d0fa7535 | 462 | /* We were not able to allocate any buffer. */ |
7c97f91e MM |
463 | close (tinfo->file); |
464 | ||
465 | err: | |
466 | xfree (tinfo); | |
467 | return NULL; | |
468 | } | |
469 | ||
470 | /* See linux-btrace.h. */ | |
471 | ||
969c39fb | 472 | enum btrace_error |
7c97f91e MM |
473 | linux_disable_btrace (struct btrace_target_info *tinfo) |
474 | { | |
475 | int errcode; | |
476 | ||
477 | errno = 0; | |
478 | errcode = munmap (tinfo->buffer, perf_event_mmap_size (tinfo)); | |
479 | if (errcode != 0) | |
969c39fb | 480 | return BTRACE_ERR_UNKNOWN; |
7c97f91e MM |
481 | |
482 | close (tinfo->file); | |
483 | xfree (tinfo); | |
484 | ||
969c39fb | 485 | return BTRACE_ERR_NONE; |
7c97f91e MM |
486 | } |
487 | ||
488 | /* Check whether the branch trace has changed. */ | |
489 | ||
490 | static int | |
491 | linux_btrace_has_changed (struct btrace_target_info *tinfo) | |
492 | { | |
493 | volatile struct perf_event_mmap_page *header = perf_event_header (tinfo); | |
494 | ||
495 | return header->data_head != tinfo->data_head; | |
496 | } | |
497 | ||
498 | /* See linux-btrace.h. */ | |
499 | ||
969c39fb MM |
500 | enum btrace_error |
501 | linux_read_btrace (VEC (btrace_block_s) **btrace, | |
502 | struct btrace_target_info *tinfo, | |
7c97f91e MM |
503 | enum btrace_read_type type) |
504 | { | |
7c97f91e MM |
505 | volatile struct perf_event_mmap_page *header; |
506 | const uint8_t *begin, *end, *start; | |
969c39fb MM |
507 | unsigned long data_head, data_tail, retries = 5; |
508 | size_t buffer_size, size; | |
7c97f91e | 509 | |
969c39fb MM |
510 | /* For delta reads, we return at least the partial last block containing |
511 | the current PC. */ | |
864089d2 | 512 | if (type == BTRACE_READ_NEW && !linux_btrace_has_changed (tinfo)) |
969c39fb | 513 | return BTRACE_ERR_NONE; |
7c97f91e MM |
514 | |
515 | header = perf_event_header (tinfo); | |
516 | buffer_size = perf_event_buffer_size (tinfo); | |
969c39fb | 517 | data_tail = tinfo->data_head; |
7c97f91e MM |
518 | |
519 | /* We may need to retry reading the trace. See below. */ | |
520 | while (retries--) | |
521 | { | |
522 | data_head = header->data_head; | |
523 | ||
ed9edfb5 | 524 | /* Delete any leftover trace from the previous iteration. */ |
969c39fb | 525 | VEC_free (btrace_block_s, *btrace); |
ed9edfb5 | 526 | |
969c39fb | 527 | if (type == BTRACE_READ_DELTA) |
7c97f91e | 528 | { |
969c39fb MM |
529 | /* Determine the number of bytes to read and check for buffer |
530 | overflows. */ | |
531 | ||
532 | /* Check for data head overflows. We might be able to recover from | |
533 | those but they are very unlikely and it's not really worth the | |
534 | effort, I think. */ | |
535 | if (data_head < data_tail) | |
536 | return BTRACE_ERR_OVERFLOW; | |
537 | ||
538 | /* If the buffer is smaller than the trace delta, we overflowed. */ | |
539 | size = data_head - data_tail; | |
540 | if (buffer_size < size) | |
541 | return BTRACE_ERR_OVERFLOW; | |
542 | } | |
543 | else | |
544 | { | |
545 | /* Read the entire buffer. */ | |
546 | size = buffer_size; | |
7c97f91e | 547 | |
969c39fb MM |
548 | /* Adjust the size if the buffer has not overflowed, yet. */ |
549 | if (data_head < size) | |
550 | size = data_head; | |
7c97f91e MM |
551 | } |
552 | ||
969c39fb MM |
553 | /* Data_head keeps growing; the buffer itself is circular. */ |
554 | begin = perf_event_buffer_begin (tinfo); | |
555 | start = begin + data_head % buffer_size; | |
556 | ||
557 | if (data_head <= buffer_size) | |
558 | end = start; | |
559 | else | |
560 | end = perf_event_buffer_end (tinfo); | |
561 | ||
562 | *btrace = perf_event_read_bts (tinfo, begin, end, start, size); | |
563 | ||
7c97f91e MM |
564 | /* The stopping thread notifies its ptracer before it is scheduled out. |
565 | On multi-core systems, the debugger might therefore run while the | |
566 | kernel might be writing the last branch trace records. | |
567 | ||
568 | Let's check whether the data head moved while we read the trace. */ | |
569 | if (data_head == header->data_head) | |
570 | break; | |
571 | } | |
572 | ||
573 | tinfo->data_head = data_head; | |
574 | ||
969c39fb MM |
575 | /* Prune the incomplete last block (i.e. the first one of inferior execution) |
576 | if we're not doing a delta read. There is no way of filling in its zeroed | |
577 | BEGIN element. */ | |
578 | if (!VEC_empty (btrace_block_s, *btrace) && type != BTRACE_READ_DELTA) | |
579 | VEC_pop (btrace_block_s, *btrace); | |
580 | ||
581 | return BTRACE_ERR_NONE; | |
7c97f91e MM |
582 | } |
583 | ||
584 | #else /* !HAVE_LINUX_PERF_EVENT_H */ | |
585 | ||
586 | /* See linux-btrace.h. */ | |
587 | ||
588 | int | |
46917d26 | 589 | linux_supports_btrace (struct target_ops *ops) |
7c97f91e MM |
590 | { |
591 | return 0; | |
592 | } | |
593 | ||
594 | /* See linux-btrace.h. */ | |
595 | ||
596 | struct btrace_target_info * | |
597 | linux_enable_btrace (ptid_t ptid) | |
598 | { | |
599 | return NULL; | |
600 | } | |
601 | ||
602 | /* See linux-btrace.h. */ | |
603 | ||
969c39fb | 604 | enum btrace_error |
7c97f91e MM |
605 | linux_disable_btrace (struct btrace_target_info *tinfo) |
606 | { | |
969c39fb | 607 | return BTRACE_ERR_NOT_SUPPORTED; |
7c97f91e MM |
608 | } |
609 | ||
610 | /* See linux-btrace.h. */ | |
611 | ||
969c39fb MM |
612 | enum btrace_error |
613 | linux_read_btrace (VEC (btrace_block_s) **btrace, | |
614 | struct btrace_target_info *tinfo, | |
7c97f91e MM |
615 | enum btrace_read_type type) |
616 | { | |
969c39fb | 617 | return BTRACE_ERR_NOT_SUPPORTED; |
7c97f91e MM |
618 | } |
619 | ||
620 | #endif /* !HAVE_LINUX_PERF_EVENT_H */ |