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Commit | Line | Data |
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71ad0f5e JO |
1 | /* |
2 | * Post mortem Dwarf CFI based unwinding on top of regs and stack dumps. | |
3 | * | |
4 | * Lots of this code have been borrowed or heavily inspired from parts of | |
5 | * the libunwind 0.99 code which are (amongst other contributors I may have | |
6 | * forgotten): | |
7 | * | |
8 | * Copyright (C) 2002-2007 Hewlett-Packard Co | |
9 | * Contributed by David Mosberger-Tang <davidm@hpl.hp.com> | |
10 | * | |
11 | * And the bugs have been added by: | |
12 | * | |
13 | * Copyright (C) 2010, Frederic Weisbecker <fweisbec@gmail.com> | |
14 | * Copyright (C) 2012, Jiri Olsa <jolsa@redhat.com> | |
15 | * | |
16 | */ | |
17 | ||
18 | #include <elf.h> | |
a43783ae | 19 | #include <errno.h> |
71ad0f5e JO |
20 | #include <gelf.h> |
21 | #include <fcntl.h> | |
fd20e811 | 22 | #include <inttypes.h> |
71ad0f5e JO |
23 | #include <string.h> |
24 | #include <unistd.h> | |
25 | #include <sys/mman.h> | |
26 | #include <linux/list.h> | |
19473e7b | 27 | #ifndef REMOTE_UNWIND_LIBUNWIND |
71ad0f5e JO |
28 | #include <libunwind.h> |
29 | #include <libunwind-ptrace.h> | |
19473e7b | 30 | #endif |
66f066d8 | 31 | #include "callchain.h" |
71ad0f5e JO |
32 | #include "thread.h" |
33 | #include "session.h" | |
34 | #include "perf_regs.h" | |
35 | #include "unwind.h" | |
99ca4233 | 36 | #include "symbol.h" |
71ad0f5e | 37 | #include "util.h" |
84f5d36f | 38 | #include "debug.h" |
e583d70c | 39 | #include "asm/bug.h" |
9343e45b | 40 | #include "dso.h" |
71ad0f5e JO |
41 | |
42 | extern int | |
43 | UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as, | |
44 | unw_word_t ip, | |
45 | unw_dyn_info_t *di, | |
46 | unw_proc_info_t *pi, | |
47 | int need_unwind_info, void *arg); | |
48 | ||
49 | #define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table) | |
50 | ||
ab255e72 JP |
51 | extern int |
52 | UNW_OBJ(dwarf_find_debug_frame) (int found, unw_dyn_info_t *di_debug, | |
53 | unw_word_t ip, | |
54 | unw_word_t segbase, | |
55 | const char *obj_name, unw_word_t start, | |
56 | unw_word_t end); | |
57 | ||
58 | #define dwarf_find_debug_frame UNW_OBJ(dwarf_find_debug_frame) | |
59 | ||
71ad0f5e JO |
60 | #define DW_EH_PE_FORMAT_MASK 0x0f /* format of the encoded value */ |
61 | #define DW_EH_PE_APPL_MASK 0x70 /* how the value is to be applied */ | |
62 | ||
63 | /* Pointer-encoding formats: */ | |
64 | #define DW_EH_PE_omit 0xff | |
65 | #define DW_EH_PE_ptr 0x00 /* pointer-sized unsigned value */ | |
66 | #define DW_EH_PE_udata4 0x03 /* unsigned 32-bit value */ | |
67 | #define DW_EH_PE_udata8 0x04 /* unsigned 64-bit value */ | |
68 | #define DW_EH_PE_sdata4 0x0b /* signed 32-bit value */ | |
69 | #define DW_EH_PE_sdata8 0x0c /* signed 64-bit value */ | |
70 | ||
71 | /* Pointer-encoding application: */ | |
72 | #define DW_EH_PE_absptr 0x00 /* absolute value */ | |
73 | #define DW_EH_PE_pcrel 0x10 /* rel. to addr. of encoded value */ | |
74 | ||
75 | /* | |
76 | * The following are not documented by LSB v1.3, yet they are used by | |
77 | * GCC, presumably they aren't documented by LSB since they aren't | |
78 | * used on Linux: | |
79 | */ | |
80 | #define DW_EH_PE_funcrel 0x40 /* start-of-procedure-relative */ | |
81 | #define DW_EH_PE_aligned 0x50 /* aligned pointer */ | |
82 | ||
83 | /* Flags intentionaly not handled, since they're not needed: | |
84 | * #define DW_EH_PE_indirect 0x80 | |
85 | * #define DW_EH_PE_uleb128 0x01 | |
86 | * #define DW_EH_PE_udata2 0x02 | |
87 | * #define DW_EH_PE_sleb128 0x09 | |
88 | * #define DW_EH_PE_sdata2 0x0a | |
89 | * #define DW_EH_PE_textrel 0x20 | |
90 | * #define DW_EH_PE_datarel 0x30 | |
91 | */ | |
92 | ||
93 | struct unwind_info { | |
94 | struct perf_sample *sample; | |
95 | struct machine *machine; | |
96 | struct thread *thread; | |
71ad0f5e JO |
97 | }; |
98 | ||
99 | #define dw_read(ptr, type, end) ({ \ | |
100 | type *__p = (type *) ptr; \ | |
101 | type __v; \ | |
102 | if ((__p + 1) > (type *) end) \ | |
103 | return -EINVAL; \ | |
104 | __v = *__p++; \ | |
105 | ptr = (typeof(ptr)) __p; \ | |
106 | __v; \ | |
107 | }) | |
108 | ||
109 | static int __dw_read_encoded_value(u8 **p, u8 *end, u64 *val, | |
110 | u8 encoding) | |
111 | { | |
112 | u8 *cur = *p; | |
113 | *val = 0; | |
114 | ||
115 | switch (encoding) { | |
116 | case DW_EH_PE_omit: | |
117 | *val = 0; | |
118 | goto out; | |
119 | case DW_EH_PE_ptr: | |
120 | *val = dw_read(cur, unsigned long, end); | |
121 | goto out; | |
122 | default: | |
123 | break; | |
124 | } | |
125 | ||
126 | switch (encoding & DW_EH_PE_APPL_MASK) { | |
127 | case DW_EH_PE_absptr: | |
128 | break; | |
129 | case DW_EH_PE_pcrel: | |
130 | *val = (unsigned long) cur; | |
131 | break; | |
132 | default: | |
133 | return -EINVAL; | |
134 | } | |
135 | ||
136 | if ((encoding & 0x07) == 0x00) | |
137 | encoding |= DW_EH_PE_udata4; | |
138 | ||
139 | switch (encoding & DW_EH_PE_FORMAT_MASK) { | |
140 | case DW_EH_PE_sdata4: | |
141 | *val += dw_read(cur, s32, end); | |
142 | break; | |
143 | case DW_EH_PE_udata4: | |
144 | *val += dw_read(cur, u32, end); | |
145 | break; | |
146 | case DW_EH_PE_sdata8: | |
147 | *val += dw_read(cur, s64, end); | |
148 | break; | |
149 | case DW_EH_PE_udata8: | |
150 | *val += dw_read(cur, u64, end); | |
151 | break; | |
152 | default: | |
153 | return -EINVAL; | |
154 | } | |
155 | ||
156 | out: | |
157 | *p = cur; | |
158 | return 0; | |
159 | } | |
160 | ||
161 | #define dw_read_encoded_value(ptr, end, enc) ({ \ | |
162 | u64 __v; \ | |
163 | if (__dw_read_encoded_value(&ptr, end, &__v, enc)) { \ | |
164 | return -EINVAL; \ | |
165 | } \ | |
166 | __v; \ | |
167 | }) | |
168 | ||
71ad0f5e JO |
169 | static u64 elf_section_offset(int fd, const char *name) |
170 | { | |
171 | Elf *elf; | |
172 | GElf_Ehdr ehdr; | |
173 | GElf_Shdr shdr; | |
174 | u64 offset = 0; | |
175 | ||
176 | elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); | |
177 | if (elf == NULL) | |
178 | return 0; | |
179 | ||
180 | do { | |
181 | if (gelf_getehdr(elf, &ehdr) == NULL) | |
182 | break; | |
183 | ||
99ca4233 | 184 | if (!elf_section_by_name(elf, &ehdr, &shdr, name, NULL)) |
71ad0f5e JO |
185 | break; |
186 | ||
187 | offset = shdr.sh_offset; | |
188 | } while (0); | |
189 | ||
190 | elf_end(elf); | |
191 | return offset; | |
192 | } | |
193 | ||
b93b0967 WN |
194 | #ifndef NO_LIBUNWIND_DEBUG_FRAME |
195 | static int elf_is_exec(int fd, const char *name) | |
196 | { | |
197 | Elf *elf; | |
198 | GElf_Ehdr ehdr; | |
199 | int retval = 0; | |
200 | ||
201 | elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); | |
202 | if (elf == NULL) | |
203 | return 0; | |
204 | if (gelf_getehdr(elf, &ehdr) == NULL) | |
205 | goto out; | |
206 | ||
207 | retval = (ehdr.e_type == ET_EXEC); | |
208 | ||
209 | out: | |
210 | elf_end(elf); | |
211 | pr_debug("unwind: elf_is_exec(%s): %d\n", name, retval); | |
212 | return retval; | |
213 | } | |
214 | #endif | |
215 | ||
71ad0f5e JO |
216 | struct table_entry { |
217 | u32 start_ip_offset; | |
218 | u32 fde_offset; | |
219 | }; | |
220 | ||
221 | struct eh_frame_hdr { | |
222 | unsigned char version; | |
223 | unsigned char eh_frame_ptr_enc; | |
224 | unsigned char fde_count_enc; | |
225 | unsigned char table_enc; | |
226 | ||
227 | /* | |
228 | * The rest of the header is variable-length and consists of the | |
229 | * following members: | |
230 | * | |
231 | * encoded_t eh_frame_ptr; | |
232 | * encoded_t fde_count; | |
233 | */ | |
234 | ||
235 | /* A single encoded pointer should not be more than 8 bytes. */ | |
236 | u64 enc[2]; | |
237 | ||
238 | /* | |
239 | * struct { | |
240 | * encoded_t start_ip; | |
241 | * encoded_t fde_addr; | |
242 | * } binary_search_table[fde_count]; | |
243 | */ | |
244 | char data[0]; | |
245 | } __packed; | |
246 | ||
247 | static int unwind_spec_ehframe(struct dso *dso, struct machine *machine, | |
248 | u64 offset, u64 *table_data, u64 *segbase, | |
249 | u64 *fde_count) | |
250 | { | |
251 | struct eh_frame_hdr hdr; | |
252 | u8 *enc = (u8 *) &hdr.enc; | |
253 | u8 *end = (u8 *) &hdr.data; | |
254 | ssize_t r; | |
255 | ||
256 | r = dso__data_read_offset(dso, machine, offset, | |
257 | (u8 *) &hdr, sizeof(hdr)); | |
258 | if (r != sizeof(hdr)) | |
259 | return -EINVAL; | |
260 | ||
261 | /* We dont need eh_frame_ptr, just skip it. */ | |
262 | dw_read_encoded_value(enc, end, hdr.eh_frame_ptr_enc); | |
263 | ||
264 | *fde_count = dw_read_encoded_value(enc, end, hdr.fde_count_enc); | |
265 | *segbase = offset; | |
266 | *table_data = (enc - (u8 *) &hdr) + offset; | |
267 | return 0; | |
268 | } | |
269 | ||
ab255e72 JP |
270 | static int read_unwind_spec_eh_frame(struct dso *dso, struct machine *machine, |
271 | u64 *table_data, u64 *segbase, | |
272 | u64 *fde_count) | |
71ad0f5e JO |
273 | { |
274 | int ret = -EINVAL, fd; | |
303cb89a | 275 | u64 offset = dso->data.eh_frame_hdr_offset; |
71ad0f5e | 276 | |
f1f13af9 | 277 | if (offset == 0) { |
4bb11d01 | 278 | fd = dso__data_get_fd(dso, machine); |
f1f13af9 NK |
279 | if (fd < 0) |
280 | return -EINVAL; | |
71ad0f5e | 281 | |
f1f13af9 NK |
282 | /* Check the .eh_frame section for unwinding info */ |
283 | offset = elf_section_offset(fd, ".eh_frame_hdr"); | |
303cb89a | 284 | dso->data.eh_frame_hdr_offset = offset; |
4bb11d01 | 285 | dso__data_put_fd(dso); |
f1f13af9 | 286 | } |
71ad0f5e JO |
287 | |
288 | if (offset) | |
289 | ret = unwind_spec_ehframe(dso, machine, offset, | |
290 | table_data, segbase, | |
291 | fde_count); | |
292 | ||
71ad0f5e JO |
293 | return ret; |
294 | } | |
295 | ||
ab255e72 JP |
296 | #ifndef NO_LIBUNWIND_DEBUG_FRAME |
297 | static int read_unwind_spec_debug_frame(struct dso *dso, | |
298 | struct machine *machine, u64 *offset) | |
299 | { | |
f1f13af9 | 300 | int fd; |
303cb89a | 301 | u64 ofs = dso->data.debug_frame_offset; |
ab255e72 | 302 | |
9343e45b MGP |
303 | /* debug_frame can reside in: |
304 | * - dso | |
305 | * - debug pointed by symsrc_filename | |
306 | * - gnu_debuglink, which doesn't necessary | |
307 | * has to be pointed by symsrc_filename | |
308 | */ | |
f1f13af9 | 309 | if (ofs == 0) { |
4bb11d01 | 310 | fd = dso__data_get_fd(dso, machine); |
9343e45b MGP |
311 | if (fd >= 0) { |
312 | ofs = elf_section_offset(fd, ".debug_frame"); | |
313 | dso__data_put_fd(dso); | |
314 | } | |
315 | ||
316 | if (ofs <= 0) { | |
317 | fd = open(dso->symsrc_filename, O_RDONLY); | |
318 | if (fd >= 0) { | |
319 | ofs = elf_section_offset(fd, ".debug_frame"); | |
320 | close(fd); | |
321 | } | |
322 | } | |
323 | ||
324 | if (ofs <= 0) { | |
325 | char *debuglink = malloc(PATH_MAX); | |
326 | int ret = 0; | |
327 | ||
328 | ret = dso__read_binary_type_filename( | |
329 | dso, DSO_BINARY_TYPE__DEBUGLINK, | |
330 | machine->root_dir, debuglink, PATH_MAX); | |
331 | if (!ret) { | |
332 | fd = open(debuglink, O_RDONLY); | |
333 | if (fd >= 0) { | |
334 | ofs = elf_section_offset(fd, | |
335 | ".debug_frame"); | |
336 | close(fd); | |
337 | } | |
338 | } | |
339 | if (ofs > 0) { | |
340 | if (dso->symsrc_filename != NULL) { | |
341 | pr_warning( | |
342 | "%s: overwrite symsrc(%s,%s)\n", | |
343 | __func__, | |
344 | dso->symsrc_filename, | |
345 | debuglink); | |
346 | free(dso->symsrc_filename); | |
347 | } | |
348 | dso->symsrc_filename = debuglink; | |
349 | } else { | |
350 | free(debuglink); | |
351 | } | |
352 | } | |
ab255e72 | 353 | |
303cb89a | 354 | dso->data.debug_frame_offset = ofs; |
f1f13af9 | 355 | } |
ab255e72 | 356 | |
f1f13af9 | 357 | *offset = ofs; |
ab255e72 JP |
358 | if (*offset) |
359 | return 0; | |
360 | ||
361 | return -EINVAL; | |
362 | } | |
363 | #endif | |
364 | ||
71ad0f5e JO |
365 | static struct map *find_map(unw_word_t ip, struct unwind_info *ui) |
366 | { | |
367 | struct addr_location al; | |
368 | ||
bb871a9c | 369 | thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER, |
326f59bf | 370 | MAP__FUNCTION, ip, &al); |
0ddf5246 JO |
371 | if (!al.map) { |
372 | /* | |
373 | * We've seen cases (softice) where DWARF unwinder went | |
374 | * through non executable mmaps, which we need to lookup | |
375 | * in MAP__VARIABLE tree. | |
376 | */ | |
377 | thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER, | |
378 | MAP__VARIABLE, ip, &al); | |
379 | } | |
71ad0f5e JO |
380 | return al.map; |
381 | } | |
382 | ||
383 | static int | |
384 | find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi, | |
385 | int need_unwind_info, void *arg) | |
386 | { | |
387 | struct unwind_info *ui = arg; | |
388 | struct map *map; | |
389 | unw_dyn_info_t di; | |
390 | u64 table_data, segbase, fde_count; | |
8eac1d5e | 391 | int ret = -EINVAL; |
71ad0f5e JO |
392 | |
393 | map = find_map(ip, ui); | |
394 | if (!map || !map->dso) | |
395 | return -EINVAL; | |
396 | ||
397 | pr_debug("unwind: find_proc_info dso %s\n", map->dso->name); | |
398 | ||
ab255e72 JP |
399 | /* Check the .eh_frame section for unwinding info */ |
400 | if (!read_unwind_spec_eh_frame(map->dso, ui->machine, | |
401 | &table_data, &segbase, &fde_count)) { | |
402 | memset(&di, 0, sizeof(di)); | |
403 | di.format = UNW_INFO_FORMAT_REMOTE_TABLE; | |
404 | di.start_ip = map->start; | |
405 | di.end_ip = map->end; | |
eac05af2 SS |
406 | di.u.rti.segbase = map->start + segbase - map->pgoff; |
407 | di.u.rti.table_data = map->start + table_data - map->pgoff; | |
ab255e72 JP |
408 | di.u.rti.table_len = fde_count * sizeof(struct table_entry) |
409 | / sizeof(unw_word_t); | |
8eac1d5e RV |
410 | ret = dwarf_search_unwind_table(as, ip, &di, pi, |
411 | need_unwind_info, arg); | |
ab255e72 JP |
412 | } |
413 | ||
414 | #ifndef NO_LIBUNWIND_DEBUG_FRAME | |
415 | /* Check the .debug_frame section for unwinding info */ | |
8eac1d5e RV |
416 | if (ret < 0 && |
417 | !read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) { | |
4bb11d01 | 418 | int fd = dso__data_get_fd(map->dso, ui->machine); |
b93b0967 WN |
419 | int is_exec = elf_is_exec(fd, map->dso->name); |
420 | unw_word_t base = is_exec ? 0 : map->start; | |
7ed4915a | 421 | const char *symfile; |
b93b0967 | 422 | |
4bb11d01 | 423 | if (fd >= 0) |
f005813a | 424 | dso__data_put_fd(map->dso); |
4bb11d01 | 425 | |
7ed4915a RV |
426 | symfile = map->dso->symsrc_filename ?: map->dso->name; |
427 | ||
ab255e72 | 428 | memset(&di, 0, sizeof(di)); |
7ed4915a | 429 | if (dwarf_find_debug_frame(0, &di, ip, base, symfile, |
d11416e7 JP |
430 | map->start, map->end)) |
431 | return dwarf_search_unwind_table(as, ip, &di, pi, | |
432 | need_unwind_info, arg); | |
ab255e72 JP |
433 | } |
434 | #endif | |
71ad0f5e | 435 | |
8eac1d5e | 436 | return ret; |
71ad0f5e JO |
437 | } |
438 | ||
1d037ca1 IT |
439 | static int access_fpreg(unw_addr_space_t __maybe_unused as, |
440 | unw_regnum_t __maybe_unused num, | |
441 | unw_fpreg_t __maybe_unused *val, | |
442 | int __maybe_unused __write, | |
443 | void __maybe_unused *arg) | |
71ad0f5e JO |
444 | { |
445 | pr_err("unwind: access_fpreg unsupported\n"); | |
446 | return -UNW_EINVAL; | |
447 | } | |
448 | ||
1d037ca1 IT |
449 | static int get_dyn_info_list_addr(unw_addr_space_t __maybe_unused as, |
450 | unw_word_t __maybe_unused *dil_addr, | |
451 | void __maybe_unused *arg) | |
71ad0f5e JO |
452 | { |
453 | return -UNW_ENOINFO; | |
454 | } | |
455 | ||
1d037ca1 IT |
456 | static int resume(unw_addr_space_t __maybe_unused as, |
457 | unw_cursor_t __maybe_unused *cu, | |
458 | void __maybe_unused *arg) | |
71ad0f5e JO |
459 | { |
460 | pr_err("unwind: resume unsupported\n"); | |
461 | return -UNW_EINVAL; | |
462 | } | |
463 | ||
464 | static int | |
1d037ca1 IT |
465 | get_proc_name(unw_addr_space_t __maybe_unused as, |
466 | unw_word_t __maybe_unused addr, | |
467 | char __maybe_unused *bufp, size_t __maybe_unused buf_len, | |
468 | unw_word_t __maybe_unused *offp, void __maybe_unused *arg) | |
71ad0f5e JO |
469 | { |
470 | pr_err("unwind: get_proc_name unsupported\n"); | |
471 | return -UNW_EINVAL; | |
472 | } | |
473 | ||
474 | static int access_dso_mem(struct unwind_info *ui, unw_word_t addr, | |
475 | unw_word_t *data) | |
476 | { | |
f22ed827 | 477 | struct map *map; |
71ad0f5e JO |
478 | ssize_t size; |
479 | ||
f22ed827 JO |
480 | map = find_map(addr, ui); |
481 | if (!map) { | |
71ad0f5e JO |
482 | pr_debug("unwind: no map for %lx\n", (unsigned long)addr); |
483 | return -1; | |
484 | } | |
485 | ||
f22ed827 | 486 | if (!map->dso) |
71ad0f5e JO |
487 | return -1; |
488 | ||
f22ed827 | 489 | size = dso__data_read_addr(map->dso, map, ui->machine, |
71ad0f5e JO |
490 | addr, (u8 *) data, sizeof(*data)); |
491 | ||
492 | return !(size == sizeof(*data)); | |
493 | } | |
494 | ||
1d037ca1 | 495 | static int access_mem(unw_addr_space_t __maybe_unused as, |
71ad0f5e JO |
496 | unw_word_t addr, unw_word_t *valp, |
497 | int __write, void *arg) | |
498 | { | |
499 | struct unwind_info *ui = arg; | |
500 | struct stack_dump *stack = &ui->sample->user_stack; | |
c9b951c4 | 501 | u64 start, end; |
71ad0f5e JO |
502 | int offset; |
503 | int ret; | |
504 | ||
505 | /* Don't support write, probably not needed. */ | |
506 | if (__write || !stack || !ui->sample->user_regs.regs) { | |
507 | *valp = 0; | |
508 | return 0; | |
509 | } | |
510 | ||
78ff1d6d HK |
511 | ret = perf_reg_value(&start, &ui->sample->user_regs, |
512 | LIBUNWIND__ARCH_REG_SP); | |
71ad0f5e JO |
513 | if (ret) |
514 | return ret; | |
515 | ||
516 | end = start + stack->size; | |
517 | ||
518 | /* Check overflow. */ | |
519 | if (addr + sizeof(unw_word_t) < addr) | |
520 | return -EINVAL; | |
521 | ||
522 | if (addr < start || addr + sizeof(unw_word_t) >= end) { | |
523 | ret = access_dso_mem(ui, addr, valp); | |
524 | if (ret) { | |
c9b951c4 JO |
525 | pr_debug("unwind: access_mem %p not inside range" |
526 | " 0x%" PRIx64 "-0x%" PRIx64 "\n", | |
186c6cfb | 527 | (void *) (uintptr_t) addr, start, end); |
71ad0f5e JO |
528 | *valp = 0; |
529 | return ret; | |
530 | } | |
531 | return 0; | |
532 | } | |
533 | ||
534 | offset = addr - start; | |
535 | *valp = *(unw_word_t *)&stack->data[offset]; | |
c9b951c4 | 536 | pr_debug("unwind: access_mem addr %p val %lx, offset %d\n", |
186c6cfb | 537 | (void *) (uintptr_t) addr, (unsigned long)*valp, offset); |
71ad0f5e JO |
538 | return 0; |
539 | } | |
540 | ||
1d037ca1 | 541 | static int access_reg(unw_addr_space_t __maybe_unused as, |
71ad0f5e JO |
542 | unw_regnum_t regnum, unw_word_t *valp, |
543 | int __write, void *arg) | |
544 | { | |
545 | struct unwind_info *ui = arg; | |
546 | int id, ret; | |
c9b951c4 | 547 | u64 val; |
71ad0f5e JO |
548 | |
549 | /* Don't support write, I suspect we don't need it. */ | |
550 | if (__write) { | |
551 | pr_err("unwind: access_reg w %d\n", regnum); | |
552 | return 0; | |
553 | } | |
554 | ||
555 | if (!ui->sample->user_regs.regs) { | |
556 | *valp = 0; | |
557 | return 0; | |
558 | } | |
559 | ||
eeb118c5 | 560 | id = LIBUNWIND__ARCH_REG_ID(regnum); |
71ad0f5e JO |
561 | if (id < 0) |
562 | return -EINVAL; | |
563 | ||
c9b951c4 | 564 | ret = perf_reg_value(&val, &ui->sample->user_regs, id); |
71ad0f5e JO |
565 | if (ret) { |
566 | pr_err("unwind: can't read reg %d\n", regnum); | |
567 | return ret; | |
568 | } | |
569 | ||
c9b951c4 | 570 | *valp = (unw_word_t) val; |
71ad0f5e JO |
571 | pr_debug("unwind: reg %d, val %lx\n", regnum, (unsigned long)*valp); |
572 | return 0; | |
573 | } | |
574 | ||
1d037ca1 IT |
575 | static void put_unwind_info(unw_addr_space_t __maybe_unused as, |
576 | unw_proc_info_t *pi __maybe_unused, | |
577 | void *arg __maybe_unused) | |
71ad0f5e JO |
578 | { |
579 | pr_debug("unwind: put_unwind_info called\n"); | |
580 | } | |
581 | ||
bb871a9c | 582 | static int entry(u64 ip, struct thread *thread, |
71ad0f5e JO |
583 | unwind_entry_cb_t cb, void *arg) |
584 | { | |
585 | struct unwind_entry e; | |
586 | struct addr_location al; | |
587 | ||
bb871a9c | 588 | thread__find_addr_location(thread, PERF_RECORD_MISC_USER, |
61710bde | 589 | MAP__FUNCTION, ip, &al); |
71ad0f5e | 590 | |
67540759 | 591 | e.ip = al.addr; |
71ad0f5e JO |
592 | e.map = al.map; |
593 | e.sym = al.sym; | |
594 | ||
595 | pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n", | |
596 | al.sym ? al.sym->name : "''", | |
597 | ip, | |
598 | al.map ? al.map->map_ip(al.map, ip) : (u64) 0); | |
599 | ||
600 | return cb(&e, arg); | |
601 | } | |
602 | ||
603 | static void display_error(int err) | |
604 | { | |
605 | switch (err) { | |
606 | case UNW_EINVAL: | |
607 | pr_err("unwind: Only supports local.\n"); | |
608 | break; | |
609 | case UNW_EUNSPEC: | |
610 | pr_err("unwind: Unspecified error.\n"); | |
611 | break; | |
612 | case UNW_EBADREG: | |
613 | pr_err("unwind: Register unavailable.\n"); | |
614 | break; | |
615 | default: | |
616 | break; | |
617 | } | |
618 | } | |
619 | ||
620 | static unw_accessors_t accessors = { | |
621 | .find_proc_info = find_proc_info, | |
622 | .put_unwind_info = put_unwind_info, | |
623 | .get_dyn_info_list_addr = get_dyn_info_list_addr, | |
624 | .access_mem = access_mem, | |
625 | .access_reg = access_reg, | |
626 | .access_fpreg = access_fpreg, | |
627 | .resume = resume, | |
628 | .get_proc_name = get_proc_name, | |
629 | }; | |
630 | ||
f83c0415 | 631 | static int _unwind__prepare_access(struct thread *thread) |
71ad0f5e | 632 | { |
66f066d8 NK |
633 | if (callchain_param.record_mode != CALLCHAIN_DWARF) |
634 | return 0; | |
71ad0f5e | 635 | |
e583d70c JO |
636 | thread->addr_space = unw_create_addr_space(&accessors, 0); |
637 | if (!thread->addr_space) { | |
71ad0f5e JO |
638 | pr_err("unwind: Can't create unwind address space.\n"); |
639 | return -ENOMEM; | |
640 | } | |
641 | ||
e583d70c | 642 | unw_set_caching_policy(thread->addr_space, UNW_CACHE_GLOBAL); |
66f066d8 NK |
643 | return 0; |
644 | } | |
645 | ||
f83c0415 | 646 | static void _unwind__flush_access(struct thread *thread) |
380b5143 | 647 | { |
380b5143 NK |
648 | if (callchain_param.record_mode != CALLCHAIN_DWARF) |
649 | return; | |
650 | ||
e583d70c | 651 | unw_flush_cache(thread->addr_space, 0, 0); |
380b5143 NK |
652 | } |
653 | ||
f83c0415 | 654 | static void _unwind__finish_access(struct thread *thread) |
66f066d8 | 655 | { |
66f066d8 NK |
656 | if (callchain_param.record_mode != CALLCHAIN_DWARF) |
657 | return; | |
658 | ||
e583d70c | 659 | unw_destroy_addr_space(thread->addr_space); |
66f066d8 NK |
660 | } |
661 | ||
662 | static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb, | |
663 | void *arg, int max_stack) | |
664 | { | |
b26b218a | 665 | u64 val; |
cb1dc22d | 666 | unw_word_t ips[max_stack]; |
66f066d8 NK |
667 | unw_addr_space_t addr_space; |
668 | unw_cursor_t c; | |
cb1dc22d | 669 | int ret, i = 0; |
66f066d8 | 670 | |
78ff1d6d HK |
671 | ret = perf_reg_value(&val, &ui->sample->user_regs, |
672 | LIBUNWIND__ARCH_REG_IP); | |
b26b218a JO |
673 | if (ret) |
674 | return ret; | |
675 | ||
cb1dc22d | 676 | ips[i++] = (unw_word_t) val; |
b26b218a | 677 | |
cb1dc22d JO |
678 | /* |
679 | * If we need more than one entry, do the DWARF | |
680 | * unwind itself. | |
681 | */ | |
682 | if (max_stack - 1 > 0) { | |
e583d70c JO |
683 | WARN_ONCE(!ui->thread, "WARNING: ui->thread is NULL"); |
684 | addr_space = ui->thread->addr_space; | |
685 | ||
cb1dc22d JO |
686 | if (addr_space == NULL) |
687 | return -1; | |
688 | ||
689 | ret = unw_init_remote(&c, addr_space, ui); | |
690 | if (ret) | |
691 | display_error(ret); | |
692 | ||
693 | while (!ret && (unw_step(&c) > 0) && i < max_stack) { | |
694 | unw_get_reg(&c, UNW_REG_IP, &ips[i]); | |
1982ad48 MW |
695 | |
696 | /* | |
697 | * Decrement the IP for any non-activation frames. | |
698 | * this is required to properly find the srcline | |
699 | * for caller frames. | |
700 | * See also the documentation for dwfl_frame_pc(), | |
701 | * which this code tries to replicate. | |
702 | */ | |
703 | if (unw_is_signal_frame(&c) <= 0) | |
704 | --ips[i]; | |
705 | ||
cb1dc22d JO |
706 | ++i; |
707 | } | |
66f066d8 | 708 | |
cb1dc22d JO |
709 | max_stack = i; |
710 | } | |
71ad0f5e | 711 | |
cb1dc22d JO |
712 | /* |
713 | * Display what we got based on the order setup. | |
714 | */ | |
715 | for (i = 0; i < max_stack && !ret; i++) { | |
716 | int j = i; | |
71ad0f5e | 717 | |
cb1dc22d JO |
718 | if (callchain_param.order == ORDER_CALLER) |
719 | j = max_stack - i - 1; | |
720 | ret = ips[j] ? entry(ips[j], ui->thread, cb, arg) : 0; | |
71ad0f5e JO |
721 | } |
722 | ||
71ad0f5e JO |
723 | return ret; |
724 | } | |
725 | ||
f83c0415 | 726 | static int _unwind__get_entries(unwind_entry_cb_t cb, void *arg, |
dd8c17a5 | 727 | struct thread *thread, |
352ea45a | 728 | struct perf_sample *data, int max_stack) |
71ad0f5e | 729 | { |
71ad0f5e JO |
730 | struct unwind_info ui = { |
731 | .sample = data, | |
71ad0f5e | 732 | .thread = thread, |
dd8c17a5 | 733 | .machine = thread->mg->machine, |
71ad0f5e | 734 | }; |
71ad0f5e JO |
735 | |
736 | if (!data->user_regs.regs) | |
737 | return -EINVAL; | |
738 | ||
b26b218a JO |
739 | if (max_stack <= 0) |
740 | return -EINVAL; | |
71ad0f5e | 741 | |
b26b218a | 742 | return get_entries(&ui, cb, arg, max_stack); |
71ad0f5e | 743 | } |
f83c0415 HK |
744 | |
745 | static struct unwind_libunwind_ops | |
746 | _unwind_libunwind_ops = { | |
747 | .prepare_access = _unwind__prepare_access, | |
748 | .flush_access = _unwind__flush_access, | |
749 | .finish_access = _unwind__finish_access, | |
750 | .get_entries = _unwind__get_entries, | |
751 | }; | |
752 | ||
19473e7b | 753 | #ifndef REMOTE_UNWIND_LIBUNWIND |
f83c0415 HK |
754 | struct unwind_libunwind_ops * |
755 | local_unwind_libunwind_ops = &_unwind_libunwind_ops; | |
19473e7b | 756 | #endif |