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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 | ||
aadf7753 | 62 | /* Return non-zero if there is new data in PEVENT; zero otherwise. */ |
7c97f91e | 63 | |
aadf7753 MM |
64 | static int |
65 | perf_event_new_data (const struct perf_event_buffer *pev) | |
7c97f91e | 66 | { |
aadf7753 | 67 | return *pev->data_head != pev->last_head; |
7c97f91e MM |
68 | } |
69 | ||
70 | /* Check whether an address is in the kernel. */ | |
71 | ||
72 | static inline int | |
73 | perf_event_is_kernel_addr (const struct btrace_target_info *tinfo, | |
74 | uint64_t addr) | |
75 | { | |
76 | uint64_t mask; | |
77 | ||
78 | /* If we don't know the size of a pointer, we can't check. Let's assume it's | |
79 | not a kernel address in this case. */ | |
80 | if (tinfo->ptr_bits == 0) | |
81 | return 0; | |
82 | ||
83 | /* A bit mask for the most significant bit in an address. */ | |
84 | mask = (uint64_t) 1 << (tinfo->ptr_bits - 1); | |
85 | ||
86 | /* Check whether the most significant bit in the address is set. */ | |
87 | return (addr & mask) != 0; | |
88 | } | |
89 | ||
90 | /* Check whether a perf event record should be skipped. */ | |
91 | ||
92 | static inline int | |
93 | perf_event_skip_record (const struct btrace_target_info *tinfo, | |
94 | const struct perf_event_bts *bts) | |
95 | { | |
96 | /* The hardware may report branches from kernel into user space. Branches | |
97 | from user into kernel space will be suppressed. We filter the former to | |
98 | provide a consistent branch trace excluding kernel. */ | |
99 | return perf_event_is_kernel_addr (tinfo, bts->from); | |
100 | } | |
101 | ||
102 | /* Perform a few consistency checks on a perf event sample record. This is | |
103 | meant to catch cases when we get out of sync with the perf event stream. */ | |
104 | ||
105 | static inline int | |
106 | perf_event_sample_ok (const struct perf_event_sample *sample) | |
107 | { | |
108 | if (sample->header.type != PERF_RECORD_SAMPLE) | |
109 | return 0; | |
110 | ||
111 | if (sample->header.size != sizeof (*sample)) | |
112 | return 0; | |
113 | ||
114 | return 1; | |
115 | } | |
116 | ||
117 | /* Branch trace is collected in a circular buffer [begin; end) as pairs of from | |
118 | and to addresses (plus a header). | |
119 | ||
120 | Start points into that buffer at the next sample position. | |
121 | We read the collected samples backwards from start. | |
122 | ||
123 | While reading the samples, we convert the information into a list of blocks. | |
124 | For two adjacent samples s1 and s2, we form a block b such that b.begin = | |
125 | s1.to and b.end = s2.from. | |
126 | ||
127 | In case the buffer overflows during sampling, one sample may have its lower | |
128 | part at the end and its upper part at the beginning of the buffer. */ | |
129 | ||
130 | static VEC (btrace_block_s) * | |
131 | perf_event_read_bts (struct btrace_target_info* tinfo, const uint8_t *begin, | |
aadf7753 MM |
132 | const uint8_t *end, const uint8_t *start, |
133 | unsigned long long size) | |
7c97f91e MM |
134 | { |
135 | VEC (btrace_block_s) *btrace = NULL; | |
136 | struct perf_event_sample sample; | |
aadf7753 | 137 | unsigned long long read = 0; |
7c97f91e MM |
138 | struct btrace_block block = { 0, 0 }; |
139 | struct regcache *regcache; | |
140 | ||
141 | gdb_assert (begin <= start); | |
142 | gdb_assert (start <= end); | |
143 | ||
144 | /* The first block ends at the current pc. */ | |
361c8ade | 145 | regcache = get_thread_regcache_for_ptid (tinfo->ptid); |
7c97f91e MM |
146 | block.end = regcache_read_pc (regcache); |
147 | ||
148 | /* The buffer may contain a partial record as its last entry (i.e. when the | |
149 | buffer size is not a multiple of the sample size). */ | |
150 | read = sizeof (sample) - 1; | |
151 | ||
152 | for (; read < size; read += sizeof (sample)) | |
153 | { | |
154 | const struct perf_event_sample *psample; | |
155 | ||
156 | /* Find the next perf_event sample in a backwards traversal. */ | |
157 | start -= sizeof (sample); | |
158 | ||
159 | /* If we're still inside the buffer, we're done. */ | |
160 | if (begin <= start) | |
161 | psample = (const struct perf_event_sample *) start; | |
162 | else | |
163 | { | |
164 | int missing; | |
165 | ||
166 | /* We're to the left of the ring buffer, we will wrap around and | |
167 | reappear at the very right of the ring buffer. */ | |
168 | ||
169 | missing = (begin - start); | |
170 | start = (end - missing); | |
171 | ||
172 | /* If the entire sample is missing, we're done. */ | |
173 | if (missing == sizeof (sample)) | |
174 | psample = (const struct perf_event_sample *) start; | |
175 | else | |
176 | { | |
177 | uint8_t *stack; | |
178 | ||
179 | /* The sample wrapped around. The lower part is at the end and | |
180 | the upper part is at the beginning of the buffer. */ | |
181 | stack = (uint8_t *) &sample; | |
182 | ||
183 | /* Copy the two parts so we have a contiguous sample. */ | |
184 | memcpy (stack, start, missing); | |
185 | memcpy (stack + missing, begin, sizeof (sample) - missing); | |
186 | ||
187 | psample = &sample; | |
188 | } | |
189 | } | |
190 | ||
191 | if (!perf_event_sample_ok (psample)) | |
192 | { | |
193 | warning (_("Branch trace may be incomplete.")); | |
194 | break; | |
195 | } | |
196 | ||
197 | if (perf_event_skip_record (tinfo, &psample->bts)) | |
198 | continue; | |
199 | ||
200 | /* We found a valid sample, so we can complete the current block. */ | |
201 | block.begin = psample->bts.to; | |
202 | ||
203 | VEC_safe_push (btrace_block_s, btrace, &block); | |
204 | ||
205 | /* Start the next block. */ | |
206 | block.end = psample->bts.from; | |
207 | } | |
208 | ||
969c39fb MM |
209 | /* Push the last block (i.e. the first one of inferior execution), as well. |
210 | We don't know where it ends, but we know where it starts. If we're | |
211 | reading delta trace, we can fill in the start address later on. | |
212 | Otherwise we will prune it. */ | |
213 | block.begin = 0; | |
214 | VEC_safe_push (btrace_block_s, btrace, &block); | |
215 | ||
7c97f91e MM |
216 | return btrace; |
217 | } | |
218 | ||
043c3577 | 219 | /* Check whether the kernel supports BTS. */ |
a950d57c MM |
220 | |
221 | static int | |
043c3577 | 222 | kernel_supports_bts (void) |
a950d57c MM |
223 | { |
224 | struct perf_event_attr attr; | |
225 | pid_t child, pid; | |
226 | int status, file; | |
227 | ||
228 | errno = 0; | |
229 | child = fork (); | |
230 | switch (child) | |
231 | { | |
232 | case -1: | |
043c3577 | 233 | warning (_("test bts: cannot fork: %s."), strerror (errno)); |
a950d57c MM |
234 | return 0; |
235 | ||
236 | case 0: | |
237 | status = ptrace (PTRACE_TRACEME, 0, NULL, NULL); | |
238 | if (status != 0) | |
239 | { | |
043c3577 | 240 | warning (_("test bts: cannot PTRACE_TRACEME: %s."), |
a950d57c MM |
241 | strerror (errno)); |
242 | _exit (1); | |
243 | } | |
244 | ||
245 | status = raise (SIGTRAP); | |
246 | if (status != 0) | |
247 | { | |
043c3577 | 248 | warning (_("test bts: cannot raise SIGTRAP: %s."), |
a950d57c MM |
249 | strerror (errno)); |
250 | _exit (1); | |
251 | } | |
252 | ||
253 | _exit (1); | |
254 | ||
255 | default: | |
256 | pid = waitpid (child, &status, 0); | |
257 | if (pid != child) | |
258 | { | |
043c3577 | 259 | warning (_("test bts: bad pid %ld, error: %s."), |
a950d57c MM |
260 | (long) pid, strerror (errno)); |
261 | return 0; | |
262 | } | |
263 | ||
264 | if (!WIFSTOPPED (status)) | |
265 | { | |
043c3577 | 266 | warning (_("test bts: expected stop. status: %d."), |
a950d57c MM |
267 | status); |
268 | return 0; | |
269 | } | |
270 | ||
271 | memset (&attr, 0, sizeof (attr)); | |
272 | ||
273 | attr.type = PERF_TYPE_HARDWARE; | |
274 | attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS; | |
275 | attr.sample_period = 1; | |
276 | attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR; | |
277 | attr.exclude_kernel = 1; | |
278 | attr.exclude_hv = 1; | |
279 | attr.exclude_idle = 1; | |
280 | ||
281 | file = syscall (SYS_perf_event_open, &attr, child, -1, -1, 0); | |
282 | if (file >= 0) | |
283 | close (file); | |
284 | ||
285 | kill (child, SIGKILL); | |
286 | ptrace (PTRACE_KILL, child, NULL, NULL); | |
287 | ||
288 | pid = waitpid (child, &status, 0); | |
289 | if (pid != child) | |
290 | { | |
043c3577 | 291 | warning (_("test bts: bad pid %ld, error: %s."), |
a950d57c MM |
292 | (long) pid, strerror (errno)); |
293 | if (!WIFSIGNALED (status)) | |
043c3577 | 294 | warning (_("test bts: expected killed. status: %d."), |
a950d57c MM |
295 | status); |
296 | } | |
297 | ||
298 | return (file >= 0); | |
299 | } | |
300 | } | |
301 | ||
043c3577 | 302 | /* Check whether an Intel cpu supports BTS. */ |
a950d57c MM |
303 | |
304 | static int | |
043c3577 | 305 | intel_supports_bts (void) |
a950d57c | 306 | { |
5f8e0b8f MF |
307 | unsigned int cpuid, model, family; |
308 | ||
df7e5265 | 309 | if (!x86_cpuid (1, &cpuid, NULL, NULL, NULL)) |
4d157a3d | 310 | return 0; |
5f8e0b8f MF |
311 | |
312 | family = (cpuid >> 8) & 0xf; | |
313 | model = (cpuid >> 4) & 0xf; | |
314 | ||
315 | switch (family) | |
316 | { | |
317 | case 0x6: | |
318 | model += (cpuid >> 12) & 0xf0; | |
319 | ||
320 | switch (model) | |
321 | { | |
322 | case 0x1a: /* Nehalem */ | |
323 | case 0x1f: | |
324 | case 0x1e: | |
325 | case 0x2e: | |
326 | case 0x25: /* Westmere */ | |
327 | case 0x2c: | |
328 | case 0x2f: | |
329 | case 0x2a: /* Sandy Bridge */ | |
330 | case 0x2d: | |
331 | case 0x3a: /* Ivy Bridge */ | |
332 | ||
333 | /* AAJ122: LBR, BTM, or BTS records may have incorrect branch | |
334 | "from" information afer an EIST transition, T-states, C1E, or | |
335 | Adaptive Thermal Throttling. */ | |
336 | return 0; | |
337 | } | |
338 | } | |
a950d57c MM |
339 | |
340 | return 1; | |
a950d57c MM |
341 | } |
342 | ||
043c3577 | 343 | /* Check whether the cpu supports BTS. */ |
a950d57c MM |
344 | |
345 | static int | |
043c3577 | 346 | cpu_supports_bts (void) |
a950d57c | 347 | { |
4d157a3d | 348 | unsigned int ebx, ecx, edx; |
a950d57c | 349 | |
df7e5265 | 350 | if (!x86_cpuid (0, NULL, &ebx, &ecx, &edx)) |
4d157a3d MF |
351 | return 0; |
352 | ||
4353c9e6 JK |
353 | if (ebx == signature_INTEL_ebx && ecx == signature_INTEL_ecx |
354 | && edx == signature_INTEL_edx) | |
043c3577 | 355 | return intel_supports_bts (); |
a950d57c MM |
356 | |
357 | /* Don't know about others. Let's assume they do. */ | |
358 | return 1; | |
a950d57c MM |
359 | } |
360 | ||
043c3577 | 361 | /* Check whether the linux target supports BTS. */ |
7c97f91e | 362 | |
043c3577 MM |
363 | static int |
364 | linux_supports_bts (void) | |
7c97f91e | 365 | { |
a950d57c MM |
366 | static int cached; |
367 | ||
368 | if (cached == 0) | |
369 | { | |
043c3577 | 370 | if (!kernel_supports_bts ()) |
a950d57c | 371 | cached = -1; |
043c3577 | 372 | else if (!cpu_supports_bts ()) |
a950d57c MM |
373 | cached = -1; |
374 | else | |
375 | cached = 1; | |
376 | } | |
377 | ||
378 | return cached > 0; | |
7c97f91e MM |
379 | } |
380 | ||
381 | /* See linux-btrace.h. */ | |
382 | ||
043c3577 MM |
383 | int |
384 | linux_supports_btrace (struct target_ops *ops, enum btrace_format format) | |
385 | { | |
386 | switch (format) | |
387 | { | |
388 | case BTRACE_FORMAT_NONE: | |
389 | return 0; | |
390 | ||
391 | case BTRACE_FORMAT_BTS: | |
392 | return linux_supports_bts (); | |
393 | } | |
394 | ||
395 | internal_error (__FILE__, __LINE__, _("Unknown branch trace format")); | |
396 | } | |
397 | ||
398 | /* See linux-btrace.h. */ | |
399 | ||
7c97f91e MM |
400 | struct btrace_target_info * |
401 | linux_enable_btrace (ptid_t ptid) | |
402 | { | |
aadf7753 | 403 | struct perf_event_mmap_page *header; |
7c97f91e | 404 | struct btrace_target_info *tinfo; |
d0fa7535 | 405 | int pid, pg; |
7c97f91e MM |
406 | |
407 | tinfo = xzalloc (sizeof (*tinfo)); | |
408 | tinfo->ptid = ptid; | |
409 | ||
410 | tinfo->attr.size = sizeof (tinfo->attr); | |
411 | tinfo->attr.type = PERF_TYPE_HARDWARE; | |
412 | tinfo->attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS; | |
413 | tinfo->attr.sample_period = 1; | |
414 | ||
415 | /* We sample from and to address. */ | |
416 | tinfo->attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR; | |
417 | ||
418 | tinfo->attr.exclude_kernel = 1; | |
419 | tinfo->attr.exclude_hv = 1; | |
420 | tinfo->attr.exclude_idle = 1; | |
421 | ||
422 | tinfo->ptr_bits = 0; | |
423 | ||
424 | pid = ptid_get_lwp (ptid); | |
425 | if (pid == 0) | |
426 | pid = ptid_get_pid (ptid); | |
427 | ||
428 | errno = 0; | |
429 | tinfo->file = syscall (SYS_perf_event_open, &tinfo->attr, pid, -1, -1, 0); | |
430 | if (tinfo->file < 0) | |
431 | goto err; | |
432 | ||
d0fa7535 MM |
433 | /* We try to allocate as much buffer as we can get. |
434 | We could allow the user to specify the size of the buffer, but then | |
435 | we'd leave this search for the maximum buffer size to him. */ | |
436 | for (pg = 4; pg >= 0; --pg) | |
437 | { | |
438 | /* The number of pages we request needs to be a power of two. */ | |
aadf7753 MM |
439 | header = mmap (NULL, ((1 << pg) + 1) * PAGE_SIZE, PROT_READ, MAP_SHARED, |
440 | tinfo->file, 0); | |
441 | if (header != MAP_FAILED) | |
442 | break; | |
d0fa7535 | 443 | } |
7c97f91e | 444 | |
aadf7753 MM |
445 | if (header == MAP_FAILED) |
446 | goto err_file; | |
447 | ||
448 | tinfo->header = header; | |
449 | tinfo->bts.mem = ((const uint8_t *) header) + PAGE_SIZE; | |
450 | tinfo->bts.size = (1 << pg) * PAGE_SIZE; | |
451 | tinfo->bts.data_head = &header->data_head; | |
452 | tinfo->bts.last_head = 0; | |
453 | ||
454 | return tinfo; | |
455 | ||
456 | err_file: | |
d0fa7535 | 457 | /* We were not able to allocate any buffer. */ |
7c97f91e MM |
458 | close (tinfo->file); |
459 | ||
460 | err: | |
461 | xfree (tinfo); | |
462 | return NULL; | |
463 | } | |
464 | ||
465 | /* See linux-btrace.h. */ | |
466 | ||
969c39fb | 467 | enum btrace_error |
7c97f91e MM |
468 | linux_disable_btrace (struct btrace_target_info *tinfo) |
469 | { | |
aadf7753 | 470 | munmap((void *) tinfo->header, tinfo->bts.size + PAGE_SIZE); |
7c97f91e MM |
471 | close (tinfo->file); |
472 | xfree (tinfo); | |
473 | ||
969c39fb | 474 | return BTRACE_ERR_NONE; |
7c97f91e MM |
475 | } |
476 | ||
734b0e4b MM |
477 | /* Read branch trace data in BTS format for the thread given by TINFO into |
478 | BTRACE using the TYPE reading method. */ | |
7c97f91e | 479 | |
734b0e4b MM |
480 | static enum btrace_error |
481 | linux_read_bts (struct btrace_data_bts *btrace, | |
482 | struct btrace_target_info *tinfo, | |
483 | enum btrace_read_type type) | |
7c97f91e | 484 | { |
aadf7753 | 485 | struct perf_event_buffer *pevent; |
7c97f91e | 486 | const uint8_t *begin, *end, *start; |
aadf7753 MM |
487 | unsigned long long data_head, data_tail, buffer_size, size; |
488 | unsigned int retries = 5; | |
489 | ||
490 | pevent = &tinfo->bts; | |
7c97f91e | 491 | |
969c39fb MM |
492 | /* For delta reads, we return at least the partial last block containing |
493 | the current PC. */ | |
aadf7753 | 494 | if (type == BTRACE_READ_NEW && !perf_event_new_data (pevent)) |
969c39fb | 495 | return BTRACE_ERR_NONE; |
7c97f91e | 496 | |
aadf7753 MM |
497 | buffer_size = pevent->size; |
498 | data_tail = pevent->last_head; | |
7c97f91e MM |
499 | |
500 | /* We may need to retry reading the trace. See below. */ | |
501 | while (retries--) | |
502 | { | |
aadf7753 | 503 | data_head = *pevent->data_head; |
7c97f91e | 504 | |
ed9edfb5 | 505 | /* Delete any leftover trace from the previous iteration. */ |
734b0e4b | 506 | VEC_free (btrace_block_s, btrace->blocks); |
ed9edfb5 | 507 | |
969c39fb | 508 | if (type == BTRACE_READ_DELTA) |
7c97f91e | 509 | { |
969c39fb MM |
510 | /* Determine the number of bytes to read and check for buffer |
511 | overflows. */ | |
512 | ||
513 | /* Check for data head overflows. We might be able to recover from | |
514 | those but they are very unlikely and it's not really worth the | |
515 | effort, I think. */ | |
516 | if (data_head < data_tail) | |
517 | return BTRACE_ERR_OVERFLOW; | |
518 | ||
519 | /* If the buffer is smaller than the trace delta, we overflowed. */ | |
520 | size = data_head - data_tail; | |
521 | if (buffer_size < size) | |
522 | return BTRACE_ERR_OVERFLOW; | |
523 | } | |
524 | else | |
525 | { | |
526 | /* Read the entire buffer. */ | |
527 | size = buffer_size; | |
7c97f91e | 528 | |
969c39fb MM |
529 | /* Adjust the size if the buffer has not overflowed, yet. */ |
530 | if (data_head < size) | |
531 | size = data_head; | |
7c97f91e MM |
532 | } |
533 | ||
969c39fb | 534 | /* Data_head keeps growing; the buffer itself is circular. */ |
aadf7753 | 535 | begin = pevent->mem; |
969c39fb MM |
536 | start = begin + data_head % buffer_size; |
537 | ||
538 | if (data_head <= buffer_size) | |
539 | end = start; | |
540 | else | |
aadf7753 | 541 | end = begin + pevent->size; |
969c39fb | 542 | |
734b0e4b | 543 | btrace->blocks = perf_event_read_bts (tinfo, begin, end, start, size); |
969c39fb | 544 | |
7c97f91e MM |
545 | /* The stopping thread notifies its ptracer before it is scheduled out. |
546 | On multi-core systems, the debugger might therefore run while the | |
547 | kernel might be writing the last branch trace records. | |
548 | ||
549 | Let's check whether the data head moved while we read the trace. */ | |
aadf7753 | 550 | if (data_head == *pevent->data_head) |
7c97f91e MM |
551 | break; |
552 | } | |
553 | ||
aadf7753 | 554 | pevent->last_head = data_head; |
7c97f91e | 555 | |
969c39fb MM |
556 | /* Prune the incomplete last block (i.e. the first one of inferior execution) |
557 | if we're not doing a delta read. There is no way of filling in its zeroed | |
558 | BEGIN element. */ | |
734b0e4b MM |
559 | if (!VEC_empty (btrace_block_s, btrace->blocks) |
560 | && type != BTRACE_READ_DELTA) | |
561 | VEC_pop (btrace_block_s, btrace->blocks); | |
969c39fb MM |
562 | |
563 | return BTRACE_ERR_NONE; | |
7c97f91e MM |
564 | } |
565 | ||
734b0e4b MM |
566 | /* See linux-btrace.h. */ |
567 | ||
568 | enum btrace_error | |
569 | linux_read_btrace (struct btrace_data *btrace, | |
570 | struct btrace_target_info *tinfo, | |
571 | enum btrace_read_type type) | |
572 | { | |
573 | /* We read btrace in BTS format. */ | |
574 | btrace->format = BTRACE_FORMAT_BTS; | |
575 | btrace->variant.bts.blocks = NULL; | |
576 | ||
577 | return linux_read_bts (&btrace->variant.bts, tinfo, type); | |
578 | } | |
579 | ||
7c97f91e MM |
580 | #else /* !HAVE_LINUX_PERF_EVENT_H */ |
581 | ||
582 | /* See linux-btrace.h. */ | |
583 | ||
584 | int | |
043c3577 | 585 | linux_supports_btrace (struct target_ops *ops, enum btrace_format format) |
7c97f91e MM |
586 | { |
587 | return 0; | |
588 | } | |
589 | ||
590 | /* See linux-btrace.h. */ | |
591 | ||
592 | struct btrace_target_info * | |
593 | linux_enable_btrace (ptid_t ptid) | |
594 | { | |
595 | return NULL; | |
596 | } | |
597 | ||
598 | /* See linux-btrace.h. */ | |
599 | ||
969c39fb | 600 | enum btrace_error |
7c97f91e MM |
601 | linux_disable_btrace (struct btrace_target_info *tinfo) |
602 | { | |
969c39fb | 603 | return BTRACE_ERR_NOT_SUPPORTED; |
7c97f91e MM |
604 | } |
605 | ||
606 | /* See linux-btrace.h. */ | |
607 | ||
969c39fb | 608 | enum btrace_error |
734b0e4b | 609 | linux_read_btrace (struct btrace_data *btrace, |
969c39fb | 610 | struct btrace_target_info *tinfo, |
7c97f91e MM |
611 | enum btrace_read_type type) |
612 | { | |
969c39fb | 613 | return BTRACE_ERR_NOT_SUPPORTED; |
7c97f91e MM |
614 | } |
615 | ||
616 | #endif /* !HAVE_LINUX_PERF_EVENT_H */ |