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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
71ad0f5e JO |
2 | /* |
3 | * Post mortem Dwarf CFI based unwinding on top of regs and stack dumps. | |
4 | * | |
5 | * Lots of this code have been borrowed or heavily inspired from parts of | |
6 | * the libunwind 0.99 code which are (amongst other contributors I may have | |
7 | * forgotten): | |
8 | * | |
9 | * Copyright (C) 2002-2007 Hewlett-Packard Co | |
10 | * Contributed by David Mosberger-Tang <davidm@hpl.hp.com> | |
11 | * | |
12 | * And the bugs have been added by: | |
13 | * | |
14 | * Copyright (C) 2010, Frederic Weisbecker <fweisbec@gmail.com> | |
15 | * Copyright (C) 2012, Jiri Olsa <jolsa@redhat.com> | |
16 | * | |
17 | */ | |
18 | ||
19 | #include <elf.h> | |
a43783ae | 20 | #include <errno.h> |
71ad0f5e JO |
21 | #include <gelf.h> |
22 | #include <fcntl.h> | |
fd20e811 | 23 | #include <inttypes.h> |
71ad0f5e JO |
24 | #include <string.h> |
25 | #include <unistd.h> | |
26 | #include <sys/mman.h> | |
27 | #include <linux/list.h> | |
19473e7b | 28 | #ifndef REMOTE_UNWIND_LIBUNWIND |
71ad0f5e JO |
29 | #include <libunwind.h> |
30 | #include <libunwind-ptrace.h> | |
19473e7b | 31 | #endif |
66f066d8 | 32 | #include "callchain.h" |
71ad0f5e JO |
33 | #include "thread.h" |
34 | #include "session.h" | |
35 | #include "perf_regs.h" | |
36 | #include "unwind.h" | |
99ca4233 | 37 | #include "symbol.h" |
71ad0f5e | 38 | #include "util.h" |
84f5d36f | 39 | #include "debug.h" |
e583d70c | 40 | #include "asm/bug.h" |
9343e45b | 41 | #include "dso.h" |
71ad0f5e JO |
42 | |
43 | extern int | |
44 | UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as, | |
45 | unw_word_t ip, | |
46 | unw_dyn_info_t *di, | |
47 | unw_proc_info_t *pi, | |
48 | int need_unwind_info, void *arg); | |
49 | ||
50 | #define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table) | |
51 | ||
ab255e72 JP |
52 | extern int |
53 | UNW_OBJ(dwarf_find_debug_frame) (int found, unw_dyn_info_t *di_debug, | |
54 | unw_word_t ip, | |
55 | unw_word_t segbase, | |
56 | const char *obj_name, unw_word_t start, | |
57 | unw_word_t end); | |
58 | ||
59 | #define dwarf_find_debug_frame UNW_OBJ(dwarf_find_debug_frame) | |
60 | ||
71ad0f5e JO |
61 | #define DW_EH_PE_FORMAT_MASK 0x0f /* format of the encoded value */ |
62 | #define DW_EH_PE_APPL_MASK 0x70 /* how the value is to be applied */ | |
63 | ||
64 | /* Pointer-encoding formats: */ | |
65 | #define DW_EH_PE_omit 0xff | |
66 | #define DW_EH_PE_ptr 0x00 /* pointer-sized unsigned value */ | |
67 | #define DW_EH_PE_udata4 0x03 /* unsigned 32-bit value */ | |
68 | #define DW_EH_PE_udata8 0x04 /* unsigned 64-bit value */ | |
69 | #define DW_EH_PE_sdata4 0x0b /* signed 32-bit value */ | |
70 | #define DW_EH_PE_sdata8 0x0c /* signed 64-bit value */ | |
71 | ||
72 | /* Pointer-encoding application: */ | |
73 | #define DW_EH_PE_absptr 0x00 /* absolute value */ | |
74 | #define DW_EH_PE_pcrel 0x10 /* rel. to addr. of encoded value */ | |
75 | ||
76 | /* | |
77 | * The following are not documented by LSB v1.3, yet they are used by | |
78 | * GCC, presumably they aren't documented by LSB since they aren't | |
79 | * used on Linux: | |
80 | */ | |
81 | #define DW_EH_PE_funcrel 0x40 /* start-of-procedure-relative */ | |
82 | #define DW_EH_PE_aligned 0x50 /* aligned pointer */ | |
83 | ||
84 | /* Flags intentionaly not handled, since they're not needed: | |
85 | * #define DW_EH_PE_indirect 0x80 | |
86 | * #define DW_EH_PE_uleb128 0x01 | |
87 | * #define DW_EH_PE_udata2 0x02 | |
88 | * #define DW_EH_PE_sleb128 0x09 | |
89 | * #define DW_EH_PE_sdata2 0x0a | |
90 | * #define DW_EH_PE_textrel 0x20 | |
91 | * #define DW_EH_PE_datarel 0x30 | |
92 | */ | |
93 | ||
94 | struct unwind_info { | |
95 | struct perf_sample *sample; | |
96 | struct machine *machine; | |
97 | struct thread *thread; | |
71ad0f5e JO |
98 | }; |
99 | ||
100 | #define dw_read(ptr, type, end) ({ \ | |
101 | type *__p = (type *) ptr; \ | |
102 | type __v; \ | |
103 | if ((__p + 1) > (type *) end) \ | |
104 | return -EINVAL; \ | |
105 | __v = *__p++; \ | |
106 | ptr = (typeof(ptr)) __p; \ | |
107 | __v; \ | |
108 | }) | |
109 | ||
110 | static int __dw_read_encoded_value(u8 **p, u8 *end, u64 *val, | |
111 | u8 encoding) | |
112 | { | |
113 | u8 *cur = *p; | |
114 | *val = 0; | |
115 | ||
116 | switch (encoding) { | |
117 | case DW_EH_PE_omit: | |
118 | *val = 0; | |
119 | goto out; | |
120 | case DW_EH_PE_ptr: | |
121 | *val = dw_read(cur, unsigned long, end); | |
122 | goto out; | |
123 | default: | |
124 | break; | |
125 | } | |
126 | ||
127 | switch (encoding & DW_EH_PE_APPL_MASK) { | |
128 | case DW_EH_PE_absptr: | |
129 | break; | |
130 | case DW_EH_PE_pcrel: | |
131 | *val = (unsigned long) cur; | |
132 | break; | |
133 | default: | |
134 | return -EINVAL; | |
135 | } | |
136 | ||
137 | if ((encoding & 0x07) == 0x00) | |
138 | encoding |= DW_EH_PE_udata4; | |
139 | ||
140 | switch (encoding & DW_EH_PE_FORMAT_MASK) { | |
141 | case DW_EH_PE_sdata4: | |
142 | *val += dw_read(cur, s32, end); | |
143 | break; | |
144 | case DW_EH_PE_udata4: | |
145 | *val += dw_read(cur, u32, end); | |
146 | break; | |
147 | case DW_EH_PE_sdata8: | |
148 | *val += dw_read(cur, s64, end); | |
149 | break; | |
150 | case DW_EH_PE_udata8: | |
151 | *val += dw_read(cur, u64, end); | |
152 | break; | |
153 | default: | |
154 | return -EINVAL; | |
155 | } | |
156 | ||
157 | out: | |
158 | *p = cur; | |
159 | return 0; | |
160 | } | |
161 | ||
162 | #define dw_read_encoded_value(ptr, end, enc) ({ \ | |
163 | u64 __v; \ | |
164 | if (__dw_read_encoded_value(&ptr, end, &__v, enc)) { \ | |
165 | return -EINVAL; \ | |
166 | } \ | |
167 | __v; \ | |
168 | }) | |
169 | ||
71ad0f5e JO |
170 | static u64 elf_section_offset(int fd, const char *name) |
171 | { | |
172 | Elf *elf; | |
173 | GElf_Ehdr ehdr; | |
174 | GElf_Shdr shdr; | |
175 | u64 offset = 0; | |
176 | ||
177 | elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); | |
178 | if (elf == NULL) | |
179 | return 0; | |
180 | ||
181 | do { | |
182 | if (gelf_getehdr(elf, &ehdr) == NULL) | |
183 | break; | |
184 | ||
99ca4233 | 185 | if (!elf_section_by_name(elf, &ehdr, &shdr, name, NULL)) |
71ad0f5e JO |
186 | break; |
187 | ||
188 | offset = shdr.sh_offset; | |
189 | } while (0); | |
190 | ||
191 | elf_end(elf); | |
192 | return offset; | |
193 | } | |
194 | ||
b93b0967 WN |
195 | #ifndef NO_LIBUNWIND_DEBUG_FRAME |
196 | static int elf_is_exec(int fd, const char *name) | |
197 | { | |
198 | Elf *elf; | |
199 | GElf_Ehdr ehdr; | |
200 | int retval = 0; | |
201 | ||
202 | elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); | |
203 | if (elf == NULL) | |
204 | return 0; | |
205 | if (gelf_getehdr(elf, &ehdr) == NULL) | |
206 | goto out; | |
207 | ||
208 | retval = (ehdr.e_type == ET_EXEC); | |
209 | ||
210 | out: | |
211 | elf_end(elf); | |
212 | pr_debug("unwind: elf_is_exec(%s): %d\n", name, retval); | |
213 | return retval; | |
214 | } | |
215 | #endif | |
216 | ||
71ad0f5e JO |
217 | struct table_entry { |
218 | u32 start_ip_offset; | |
219 | u32 fde_offset; | |
220 | }; | |
221 | ||
222 | struct eh_frame_hdr { | |
223 | unsigned char version; | |
224 | unsigned char eh_frame_ptr_enc; | |
225 | unsigned char fde_count_enc; | |
226 | unsigned char table_enc; | |
227 | ||
228 | /* | |
229 | * The rest of the header is variable-length and consists of the | |
230 | * following members: | |
231 | * | |
232 | * encoded_t eh_frame_ptr; | |
233 | * encoded_t fde_count; | |
234 | */ | |
235 | ||
236 | /* A single encoded pointer should not be more than 8 bytes. */ | |
237 | u64 enc[2]; | |
238 | ||
239 | /* | |
240 | * struct { | |
241 | * encoded_t start_ip; | |
242 | * encoded_t fde_addr; | |
243 | * } binary_search_table[fde_count]; | |
244 | */ | |
245 | char data[0]; | |
246 | } __packed; | |
247 | ||
248 | static int unwind_spec_ehframe(struct dso *dso, struct machine *machine, | |
249 | u64 offset, u64 *table_data, u64 *segbase, | |
250 | u64 *fde_count) | |
251 | { | |
252 | struct eh_frame_hdr hdr; | |
253 | u8 *enc = (u8 *) &hdr.enc; | |
254 | u8 *end = (u8 *) &hdr.data; | |
255 | ssize_t r; | |
256 | ||
257 | r = dso__data_read_offset(dso, machine, offset, | |
258 | (u8 *) &hdr, sizeof(hdr)); | |
259 | if (r != sizeof(hdr)) | |
260 | return -EINVAL; | |
261 | ||
262 | /* We dont need eh_frame_ptr, just skip it. */ | |
263 | dw_read_encoded_value(enc, end, hdr.eh_frame_ptr_enc); | |
264 | ||
265 | *fde_count = dw_read_encoded_value(enc, end, hdr.fde_count_enc); | |
266 | *segbase = offset; | |
267 | *table_data = (enc - (u8 *) &hdr) + offset; | |
268 | return 0; | |
269 | } | |
270 | ||
ab255e72 JP |
271 | static int read_unwind_spec_eh_frame(struct dso *dso, struct machine *machine, |
272 | u64 *table_data, u64 *segbase, | |
273 | u64 *fde_count) | |
71ad0f5e JO |
274 | { |
275 | int ret = -EINVAL, fd; | |
303cb89a | 276 | u64 offset = dso->data.eh_frame_hdr_offset; |
71ad0f5e | 277 | |
f1f13af9 | 278 | if (offset == 0) { |
4bb11d01 | 279 | fd = dso__data_get_fd(dso, machine); |
f1f13af9 NK |
280 | if (fd < 0) |
281 | return -EINVAL; | |
71ad0f5e | 282 | |
f1f13af9 NK |
283 | /* Check the .eh_frame section for unwinding info */ |
284 | offset = elf_section_offset(fd, ".eh_frame_hdr"); | |
303cb89a | 285 | dso->data.eh_frame_hdr_offset = offset; |
4bb11d01 | 286 | dso__data_put_fd(dso); |
f1f13af9 | 287 | } |
71ad0f5e JO |
288 | |
289 | if (offset) | |
290 | ret = unwind_spec_ehframe(dso, machine, offset, | |
291 | table_data, segbase, | |
292 | fde_count); | |
293 | ||
71ad0f5e JO |
294 | return ret; |
295 | } | |
296 | ||
ab255e72 JP |
297 | #ifndef NO_LIBUNWIND_DEBUG_FRAME |
298 | static int read_unwind_spec_debug_frame(struct dso *dso, | |
299 | struct machine *machine, u64 *offset) | |
300 | { | |
f1f13af9 | 301 | int fd; |
303cb89a | 302 | u64 ofs = dso->data.debug_frame_offset; |
ab255e72 | 303 | |
9343e45b MGP |
304 | /* debug_frame can reside in: |
305 | * - dso | |
306 | * - debug pointed by symsrc_filename | |
307 | * - gnu_debuglink, which doesn't necessary | |
308 | * has to be pointed by symsrc_filename | |
309 | */ | |
f1f13af9 | 310 | if (ofs == 0) { |
4bb11d01 | 311 | fd = dso__data_get_fd(dso, machine); |
9343e45b MGP |
312 | if (fd >= 0) { |
313 | ofs = elf_section_offset(fd, ".debug_frame"); | |
314 | dso__data_put_fd(dso); | |
315 | } | |
316 | ||
317 | if (ofs <= 0) { | |
318 | fd = open(dso->symsrc_filename, O_RDONLY); | |
319 | if (fd >= 0) { | |
320 | ofs = elf_section_offset(fd, ".debug_frame"); | |
321 | close(fd); | |
322 | } | |
323 | } | |
324 | ||
325 | if (ofs <= 0) { | |
326 | char *debuglink = malloc(PATH_MAX); | |
327 | int ret = 0; | |
328 | ||
329 | ret = dso__read_binary_type_filename( | |
330 | dso, DSO_BINARY_TYPE__DEBUGLINK, | |
331 | machine->root_dir, debuglink, PATH_MAX); | |
332 | if (!ret) { | |
333 | fd = open(debuglink, O_RDONLY); | |
334 | if (fd >= 0) { | |
335 | ofs = elf_section_offset(fd, | |
336 | ".debug_frame"); | |
337 | close(fd); | |
338 | } | |
339 | } | |
340 | if (ofs > 0) { | |
341 | if (dso->symsrc_filename != NULL) { | |
342 | pr_warning( | |
343 | "%s: overwrite symsrc(%s,%s)\n", | |
344 | __func__, | |
345 | dso->symsrc_filename, | |
346 | debuglink); | |
347 | free(dso->symsrc_filename); | |
348 | } | |
349 | dso->symsrc_filename = debuglink; | |
350 | } else { | |
351 | free(debuglink); | |
352 | } | |
353 | } | |
ab255e72 | 354 | |
303cb89a | 355 | dso->data.debug_frame_offset = ofs; |
f1f13af9 | 356 | } |
ab255e72 | 357 | |
f1f13af9 | 358 | *offset = ofs; |
ab255e72 JP |
359 | if (*offset) |
360 | return 0; | |
361 | ||
362 | return -EINVAL; | |
363 | } | |
364 | #endif | |
365 | ||
71ad0f5e JO |
366 | static struct map *find_map(unw_word_t ip, struct unwind_info *ui) |
367 | { | |
368 | struct addr_location al; | |
369 | ||
bb871a9c | 370 | thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER, |
326f59bf | 371 | MAP__FUNCTION, ip, &al); |
0ddf5246 JO |
372 | if (!al.map) { |
373 | /* | |
374 | * We've seen cases (softice) where DWARF unwinder went | |
375 | * through non executable mmaps, which we need to lookup | |
376 | * in MAP__VARIABLE tree. | |
377 | */ | |
378 | thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER, | |
379 | MAP__VARIABLE, ip, &al); | |
380 | } | |
71ad0f5e JO |
381 | return al.map; |
382 | } | |
383 | ||
384 | static int | |
385 | find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi, | |
386 | int need_unwind_info, void *arg) | |
387 | { | |
388 | struct unwind_info *ui = arg; | |
389 | struct map *map; | |
390 | unw_dyn_info_t di; | |
391 | u64 table_data, segbase, fde_count; | |
8eac1d5e | 392 | int ret = -EINVAL; |
71ad0f5e JO |
393 | |
394 | map = find_map(ip, ui); | |
395 | if (!map || !map->dso) | |
396 | return -EINVAL; | |
397 | ||
398 | pr_debug("unwind: find_proc_info dso %s\n", map->dso->name); | |
399 | ||
ab255e72 JP |
400 | /* Check the .eh_frame section for unwinding info */ |
401 | if (!read_unwind_spec_eh_frame(map->dso, ui->machine, | |
402 | &table_data, &segbase, &fde_count)) { | |
403 | memset(&di, 0, sizeof(di)); | |
404 | di.format = UNW_INFO_FORMAT_REMOTE_TABLE; | |
405 | di.start_ip = map->start; | |
406 | di.end_ip = map->end; | |
eac05af2 SS |
407 | di.u.rti.segbase = map->start + segbase - map->pgoff; |
408 | di.u.rti.table_data = map->start + table_data - map->pgoff; | |
ab255e72 JP |
409 | di.u.rti.table_len = fde_count * sizeof(struct table_entry) |
410 | / sizeof(unw_word_t); | |
8eac1d5e RV |
411 | ret = dwarf_search_unwind_table(as, ip, &di, pi, |
412 | need_unwind_info, arg); | |
ab255e72 JP |
413 | } |
414 | ||
415 | #ifndef NO_LIBUNWIND_DEBUG_FRAME | |
416 | /* Check the .debug_frame section for unwinding info */ | |
8eac1d5e RV |
417 | if (ret < 0 && |
418 | !read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) { | |
4bb11d01 | 419 | int fd = dso__data_get_fd(map->dso, ui->machine); |
b93b0967 WN |
420 | int is_exec = elf_is_exec(fd, map->dso->name); |
421 | unw_word_t base = is_exec ? 0 : map->start; | |
7ed4915a | 422 | const char *symfile; |
b93b0967 | 423 | |
4bb11d01 | 424 | if (fd >= 0) |
f005813a | 425 | dso__data_put_fd(map->dso); |
4bb11d01 | 426 | |
7ed4915a RV |
427 | symfile = map->dso->symsrc_filename ?: map->dso->name; |
428 | ||
ab255e72 | 429 | memset(&di, 0, sizeof(di)); |
7ed4915a | 430 | if (dwarf_find_debug_frame(0, &di, ip, base, symfile, |
d11416e7 JP |
431 | map->start, map->end)) |
432 | return dwarf_search_unwind_table(as, ip, &di, pi, | |
433 | need_unwind_info, arg); | |
ab255e72 JP |
434 | } |
435 | #endif | |
71ad0f5e | 436 | |
8eac1d5e | 437 | return ret; |
71ad0f5e JO |
438 | } |
439 | ||
1d037ca1 IT |
440 | static int access_fpreg(unw_addr_space_t __maybe_unused as, |
441 | unw_regnum_t __maybe_unused num, | |
442 | unw_fpreg_t __maybe_unused *val, | |
443 | int __maybe_unused __write, | |
444 | void __maybe_unused *arg) | |
71ad0f5e JO |
445 | { |
446 | pr_err("unwind: access_fpreg unsupported\n"); | |
447 | return -UNW_EINVAL; | |
448 | } | |
449 | ||
1d037ca1 IT |
450 | static int get_dyn_info_list_addr(unw_addr_space_t __maybe_unused as, |
451 | unw_word_t __maybe_unused *dil_addr, | |
452 | void __maybe_unused *arg) | |
71ad0f5e JO |
453 | { |
454 | return -UNW_ENOINFO; | |
455 | } | |
456 | ||
1d037ca1 IT |
457 | static int resume(unw_addr_space_t __maybe_unused as, |
458 | unw_cursor_t __maybe_unused *cu, | |
459 | void __maybe_unused *arg) | |
71ad0f5e JO |
460 | { |
461 | pr_err("unwind: resume unsupported\n"); | |
462 | return -UNW_EINVAL; | |
463 | } | |
464 | ||
465 | static int | |
1d037ca1 IT |
466 | get_proc_name(unw_addr_space_t __maybe_unused as, |
467 | unw_word_t __maybe_unused addr, | |
468 | char __maybe_unused *bufp, size_t __maybe_unused buf_len, | |
469 | unw_word_t __maybe_unused *offp, void __maybe_unused *arg) | |
71ad0f5e JO |
470 | { |
471 | pr_err("unwind: get_proc_name unsupported\n"); | |
472 | return -UNW_EINVAL; | |
473 | } | |
474 | ||
475 | static int access_dso_mem(struct unwind_info *ui, unw_word_t addr, | |
476 | unw_word_t *data) | |
477 | { | |
f22ed827 | 478 | struct map *map; |
71ad0f5e JO |
479 | ssize_t size; |
480 | ||
f22ed827 JO |
481 | map = find_map(addr, ui); |
482 | if (!map) { | |
71ad0f5e JO |
483 | pr_debug("unwind: no map for %lx\n", (unsigned long)addr); |
484 | return -1; | |
485 | } | |
486 | ||
f22ed827 | 487 | if (!map->dso) |
71ad0f5e JO |
488 | return -1; |
489 | ||
f22ed827 | 490 | size = dso__data_read_addr(map->dso, map, ui->machine, |
71ad0f5e JO |
491 | addr, (u8 *) data, sizeof(*data)); |
492 | ||
493 | return !(size == sizeof(*data)); | |
494 | } | |
495 | ||
1d037ca1 | 496 | static int access_mem(unw_addr_space_t __maybe_unused as, |
71ad0f5e JO |
497 | unw_word_t addr, unw_word_t *valp, |
498 | int __write, void *arg) | |
499 | { | |
500 | struct unwind_info *ui = arg; | |
501 | struct stack_dump *stack = &ui->sample->user_stack; | |
c9b951c4 | 502 | u64 start, end; |
71ad0f5e JO |
503 | int offset; |
504 | int ret; | |
505 | ||
506 | /* Don't support write, probably not needed. */ | |
507 | if (__write || !stack || !ui->sample->user_regs.regs) { | |
508 | *valp = 0; | |
509 | return 0; | |
510 | } | |
511 | ||
78ff1d6d HK |
512 | ret = perf_reg_value(&start, &ui->sample->user_regs, |
513 | LIBUNWIND__ARCH_REG_SP); | |
71ad0f5e JO |
514 | if (ret) |
515 | return ret; | |
516 | ||
517 | end = start + stack->size; | |
518 | ||
519 | /* Check overflow. */ | |
520 | if (addr + sizeof(unw_word_t) < addr) | |
521 | return -EINVAL; | |
522 | ||
523 | if (addr < start || addr + sizeof(unw_word_t) >= end) { | |
524 | ret = access_dso_mem(ui, addr, valp); | |
525 | if (ret) { | |
c9b951c4 JO |
526 | pr_debug("unwind: access_mem %p not inside range" |
527 | " 0x%" PRIx64 "-0x%" PRIx64 "\n", | |
186c6cfb | 528 | (void *) (uintptr_t) addr, start, end); |
71ad0f5e JO |
529 | *valp = 0; |
530 | return ret; | |
531 | } | |
532 | return 0; | |
533 | } | |
534 | ||
535 | offset = addr - start; | |
536 | *valp = *(unw_word_t *)&stack->data[offset]; | |
c9b951c4 | 537 | pr_debug("unwind: access_mem addr %p val %lx, offset %d\n", |
186c6cfb | 538 | (void *) (uintptr_t) addr, (unsigned long)*valp, offset); |
71ad0f5e JO |
539 | return 0; |
540 | } | |
541 | ||
1d037ca1 | 542 | static int access_reg(unw_addr_space_t __maybe_unused as, |
71ad0f5e JO |
543 | unw_regnum_t regnum, unw_word_t *valp, |
544 | int __write, void *arg) | |
545 | { | |
546 | struct unwind_info *ui = arg; | |
547 | int id, ret; | |
c9b951c4 | 548 | u64 val; |
71ad0f5e JO |
549 | |
550 | /* Don't support write, I suspect we don't need it. */ | |
551 | if (__write) { | |
552 | pr_err("unwind: access_reg w %d\n", regnum); | |
553 | return 0; | |
554 | } | |
555 | ||
556 | if (!ui->sample->user_regs.regs) { | |
557 | *valp = 0; | |
558 | return 0; | |
559 | } | |
560 | ||
eeb118c5 | 561 | id = LIBUNWIND__ARCH_REG_ID(regnum); |
71ad0f5e JO |
562 | if (id < 0) |
563 | return -EINVAL; | |
564 | ||
c9b951c4 | 565 | ret = perf_reg_value(&val, &ui->sample->user_regs, id); |
71ad0f5e JO |
566 | if (ret) { |
567 | pr_err("unwind: can't read reg %d\n", regnum); | |
568 | return ret; | |
569 | } | |
570 | ||
c9b951c4 | 571 | *valp = (unw_word_t) val; |
71ad0f5e JO |
572 | pr_debug("unwind: reg %d, val %lx\n", regnum, (unsigned long)*valp); |
573 | return 0; | |
574 | } | |
575 | ||
1d037ca1 IT |
576 | static void put_unwind_info(unw_addr_space_t __maybe_unused as, |
577 | unw_proc_info_t *pi __maybe_unused, | |
578 | void *arg __maybe_unused) | |
71ad0f5e JO |
579 | { |
580 | pr_debug("unwind: put_unwind_info called\n"); | |
581 | } | |
582 | ||
bb871a9c | 583 | static int entry(u64 ip, struct thread *thread, |
71ad0f5e JO |
584 | unwind_entry_cb_t cb, void *arg) |
585 | { | |
586 | struct unwind_entry e; | |
587 | struct addr_location al; | |
588 | ||
bb871a9c | 589 | thread__find_addr_location(thread, PERF_RECORD_MISC_USER, |
61710bde | 590 | MAP__FUNCTION, ip, &al); |
71ad0f5e | 591 | |
67540759 | 592 | e.ip = al.addr; |
71ad0f5e JO |
593 | e.map = al.map; |
594 | e.sym = al.sym; | |
595 | ||
596 | pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n", | |
597 | al.sym ? al.sym->name : "''", | |
598 | ip, | |
599 | al.map ? al.map->map_ip(al.map, ip) : (u64) 0); | |
600 | ||
601 | return cb(&e, arg); | |
602 | } | |
603 | ||
604 | static void display_error(int err) | |
605 | { | |
606 | switch (err) { | |
607 | case UNW_EINVAL: | |
608 | pr_err("unwind: Only supports local.\n"); | |
609 | break; | |
610 | case UNW_EUNSPEC: | |
611 | pr_err("unwind: Unspecified error.\n"); | |
612 | break; | |
613 | case UNW_EBADREG: | |
614 | pr_err("unwind: Register unavailable.\n"); | |
615 | break; | |
616 | default: | |
617 | break; | |
618 | } | |
619 | } | |
620 | ||
621 | static unw_accessors_t accessors = { | |
622 | .find_proc_info = find_proc_info, | |
623 | .put_unwind_info = put_unwind_info, | |
624 | .get_dyn_info_list_addr = get_dyn_info_list_addr, | |
625 | .access_mem = access_mem, | |
626 | .access_reg = access_reg, | |
627 | .access_fpreg = access_fpreg, | |
628 | .resume = resume, | |
629 | .get_proc_name = get_proc_name, | |
630 | }; | |
631 | ||
f83c0415 | 632 | static int _unwind__prepare_access(struct thread *thread) |
71ad0f5e | 633 | { |
66f066d8 NK |
634 | if (callchain_param.record_mode != CALLCHAIN_DWARF) |
635 | return 0; | |
71ad0f5e | 636 | |
e583d70c JO |
637 | thread->addr_space = unw_create_addr_space(&accessors, 0); |
638 | if (!thread->addr_space) { | |
71ad0f5e JO |
639 | pr_err("unwind: Can't create unwind address space.\n"); |
640 | return -ENOMEM; | |
641 | } | |
642 | ||
e583d70c | 643 | unw_set_caching_policy(thread->addr_space, UNW_CACHE_GLOBAL); |
66f066d8 NK |
644 | return 0; |
645 | } | |
646 | ||
f83c0415 | 647 | static void _unwind__flush_access(struct thread *thread) |
380b5143 | 648 | { |
380b5143 NK |
649 | if (callchain_param.record_mode != CALLCHAIN_DWARF) |
650 | return; | |
651 | ||
e583d70c | 652 | unw_flush_cache(thread->addr_space, 0, 0); |
380b5143 NK |
653 | } |
654 | ||
f83c0415 | 655 | static void _unwind__finish_access(struct thread *thread) |
66f066d8 | 656 | { |
66f066d8 NK |
657 | if (callchain_param.record_mode != CALLCHAIN_DWARF) |
658 | return; | |
659 | ||
e583d70c | 660 | unw_destroy_addr_space(thread->addr_space); |
66f066d8 NK |
661 | } |
662 | ||
663 | static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb, | |
664 | void *arg, int max_stack) | |
665 | { | |
b26b218a | 666 | u64 val; |
cb1dc22d | 667 | unw_word_t ips[max_stack]; |
66f066d8 NK |
668 | unw_addr_space_t addr_space; |
669 | unw_cursor_t c; | |
cb1dc22d | 670 | int ret, i = 0; |
66f066d8 | 671 | |
78ff1d6d HK |
672 | ret = perf_reg_value(&val, &ui->sample->user_regs, |
673 | LIBUNWIND__ARCH_REG_IP); | |
b26b218a JO |
674 | if (ret) |
675 | return ret; | |
676 | ||
cb1dc22d | 677 | ips[i++] = (unw_word_t) val; |
b26b218a | 678 | |
cb1dc22d JO |
679 | /* |
680 | * If we need more than one entry, do the DWARF | |
681 | * unwind itself. | |
682 | */ | |
683 | if (max_stack - 1 > 0) { | |
e583d70c JO |
684 | WARN_ONCE(!ui->thread, "WARNING: ui->thread is NULL"); |
685 | addr_space = ui->thread->addr_space; | |
686 | ||
cb1dc22d JO |
687 | if (addr_space == NULL) |
688 | return -1; | |
689 | ||
690 | ret = unw_init_remote(&c, addr_space, ui); | |
691 | if (ret) | |
692 | display_error(ret); | |
693 | ||
694 | while (!ret && (unw_step(&c) > 0) && i < max_stack) { | |
695 | unw_get_reg(&c, UNW_REG_IP, &ips[i]); | |
1982ad48 MW |
696 | |
697 | /* | |
698 | * Decrement the IP for any non-activation frames. | |
699 | * this is required to properly find the srcline | |
700 | * for caller frames. | |
701 | * See also the documentation for dwfl_frame_pc(), | |
702 | * which this code tries to replicate. | |
703 | */ | |
704 | if (unw_is_signal_frame(&c) <= 0) | |
705 | --ips[i]; | |
706 | ||
cb1dc22d JO |
707 | ++i; |
708 | } | |
66f066d8 | 709 | |
cb1dc22d JO |
710 | max_stack = i; |
711 | } | |
71ad0f5e | 712 | |
cb1dc22d JO |
713 | /* |
714 | * Display what we got based on the order setup. | |
715 | */ | |
716 | for (i = 0; i < max_stack && !ret; i++) { | |
717 | int j = i; | |
71ad0f5e | 718 | |
cb1dc22d JO |
719 | if (callchain_param.order == ORDER_CALLER) |
720 | j = max_stack - i - 1; | |
721 | ret = ips[j] ? entry(ips[j], ui->thread, cb, arg) : 0; | |
71ad0f5e JO |
722 | } |
723 | ||
71ad0f5e JO |
724 | return ret; |
725 | } | |
726 | ||
f83c0415 | 727 | static int _unwind__get_entries(unwind_entry_cb_t cb, void *arg, |
dd8c17a5 | 728 | struct thread *thread, |
352ea45a | 729 | struct perf_sample *data, int max_stack) |
71ad0f5e | 730 | { |
71ad0f5e JO |
731 | struct unwind_info ui = { |
732 | .sample = data, | |
71ad0f5e | 733 | .thread = thread, |
dd8c17a5 | 734 | .machine = thread->mg->machine, |
71ad0f5e | 735 | }; |
71ad0f5e JO |
736 | |
737 | if (!data->user_regs.regs) | |
738 | return -EINVAL; | |
739 | ||
b26b218a JO |
740 | if (max_stack <= 0) |
741 | return -EINVAL; | |
71ad0f5e | 742 | |
b26b218a | 743 | return get_entries(&ui, cb, arg, max_stack); |
71ad0f5e | 744 | } |
f83c0415 HK |
745 | |
746 | static struct unwind_libunwind_ops | |
747 | _unwind_libunwind_ops = { | |
748 | .prepare_access = _unwind__prepare_access, | |
749 | .flush_access = _unwind__flush_access, | |
750 | .finish_access = _unwind__finish_access, | |
751 | .get_entries = _unwind__get_entries, | |
752 | }; | |
753 | ||
19473e7b | 754 | #ifndef REMOTE_UNWIND_LIBUNWIND |
f83c0415 HK |
755 | struct unwind_libunwind_ops * |
756 | local_unwind_libunwind_ops = &_unwind_libunwind_ops; | |
19473e7b | 757 | #endif |