blob: f8455bed6e653705183b878c40d294991edf4e92 [file] [log] [blame]
Jiri Olsa71ad0f52012-08-07 15:20:46 +02001/*
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>
Arnaldo Carvalho de Meloa43783a2017-04-18 10:46:11 -030019#include <errno.h>
Jiri Olsa71ad0f52012-08-07 15:20:46 +020020#include <gelf.h>
21#include <fcntl.h>
Arnaldo Carvalho de Melofd20e812017-04-17 15:23:08 -030022#include <inttypes.h>
Jiri Olsa71ad0f52012-08-07 15:20:46 +020023#include <string.h>
24#include <unistd.h>
25#include <sys/mman.h>
26#include <linux/list.h>
He Kuang19473e72016-06-03 03:33:21 +000027#ifndef REMOTE_UNWIND_LIBUNWIND
Jiri Olsa71ad0f52012-08-07 15:20:46 +020028#include <libunwind.h>
29#include <libunwind-ptrace.h>
He Kuang19473e72016-06-03 03:33:21 +000030#endif
Namhyung Kim66f066d82014-10-06 09:46:00 +090031#include "callchain.h"
Jiri Olsa71ad0f52012-08-07 15:20:46 +020032#include "thread.h"
33#include "session.h"
34#include "perf_regs.h"
35#include "unwind.h"
Masami Hiramatsu99ca4232014-01-16 09:39:49 +000036#include "symbol.h"
Jiri Olsa71ad0f52012-08-07 15:20:46 +020037#include "util.h"
Jiri Olsa84f5d362014-07-14 23:46:48 +020038#include "debug.h"
Jiri Olsae583d702016-04-07 09:11:12 +020039#include "asm/bug.h"
Matija Glavinic Pecotic9343e452017-01-17 15:50:35 +010040#include "dso.h"
Jiri Olsa71ad0f52012-08-07 15:20:46 +020041
42extern int
43UNW_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
Jean Pihetab255e72013-09-26 12:36:38 +010051extern int
52UNW_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
Jiri Olsa71ad0f52012-08-07 15:20:46 +020060#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
93struct unwind_info {
94 struct perf_sample *sample;
95 struct machine *machine;
96 struct thread *thread;
Jiri Olsa71ad0f52012-08-07 15:20:46 +020097};
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
109static 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
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200169static 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
Masami Hiramatsu99ca4232014-01-16 09:39:49 +0000184 if (!elf_section_by_name(elf, &ehdr, &shdr, name, NULL))
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200185 break;
186
187 offset = shdr.sh_offset;
188 } while (0);
189
190 elf_end(elf);
191 return offset;
192}
193
Wang Nanb93b0962015-01-14 10:36:47 +0800194#ifndef NO_LIBUNWIND_DEBUG_FRAME
195static 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
209out:
210 elf_end(elf);
211 pr_debug("unwind: elf_is_exec(%s): %d\n", name, retval);
212 return retval;
213}
214#endif
215
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200216struct table_entry {
217 u32 start_ip_offset;
218 u32 fde_offset;
219};
220
221struct 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
247static 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
Jean Pihetab255e72013-09-26 12:36:38 +0100270static int read_unwind_spec_eh_frame(struct dso *dso, struct machine *machine,
271 u64 *table_data, u64 *segbase,
272 u64 *fde_count)
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200273{
274 int ret = -EINVAL, fd;
Wang Nan303cb892015-03-13 15:02:56 +0800275 u64 offset = dso->data.eh_frame_hdr_offset;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200276
Namhyung Kimf1f13af2015-01-29 17:07:21 +0900277 if (offset == 0) {
Namhyung Kim4bb11d02015-05-21 01:03:41 +0900278 fd = dso__data_get_fd(dso, machine);
Namhyung Kimf1f13af2015-01-29 17:07:21 +0900279 if (fd < 0)
280 return -EINVAL;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200281
Namhyung Kimf1f13af2015-01-29 17:07:21 +0900282 /* Check the .eh_frame section for unwinding info */
283 offset = elf_section_offset(fd, ".eh_frame_hdr");
Wang Nan303cb892015-03-13 15:02:56 +0800284 dso->data.eh_frame_hdr_offset = offset;
Namhyung Kim4bb11d02015-05-21 01:03:41 +0900285 dso__data_put_fd(dso);
Namhyung Kimf1f13af2015-01-29 17:07:21 +0900286 }
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200287
288 if (offset)
289 ret = unwind_spec_ehframe(dso, machine, offset,
290 table_data, segbase,
291 fde_count);
292
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200293 return ret;
294}
295
Jean Pihetab255e72013-09-26 12:36:38 +0100296#ifndef NO_LIBUNWIND_DEBUG_FRAME
297static int read_unwind_spec_debug_frame(struct dso *dso,
298 struct machine *machine, u64 *offset)
299{
Namhyung Kimf1f13af2015-01-29 17:07:21 +0900300 int fd;
Wang Nan303cb892015-03-13 15:02:56 +0800301 u64 ofs = dso->data.debug_frame_offset;
Jean Pihetab255e72013-09-26 12:36:38 +0100302
Matija Glavinic Pecotic9343e452017-01-17 15:50:35 +0100303 /* 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 */
Namhyung Kimf1f13af2015-01-29 17:07:21 +0900309 if (ofs == 0) {
Namhyung Kim4bb11d02015-05-21 01:03:41 +0900310 fd = dso__data_get_fd(dso, machine);
Matija Glavinic Pecotic9343e452017-01-17 15:50:35 +0100311 if (fd >= 0) {
312 ofs = elf_section_offset(fd, ".debug_frame");
313 dso__data_put_fd(dso);
314 }
Jean Pihetab255e72013-09-26 12:36:38 +0100315
Matija Glavinic Pecotic9343e452017-01-17 15:50:35 +0100316 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 }
353
Wang Nan303cb892015-03-13 15:02:56 +0800354 dso->data.debug_frame_offset = ofs;
Namhyung Kimf1f13af2015-01-29 17:07:21 +0900355 }
Jean Pihetab255e72013-09-26 12:36:38 +0100356
Namhyung Kimf1f13af2015-01-29 17:07:21 +0900357 *offset = ofs;
Jean Pihetab255e72013-09-26 12:36:38 +0100358 if (*offset)
359 return 0;
360
361 return -EINVAL;
362}
363#endif
364
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200365static struct map *find_map(unw_word_t ip, struct unwind_info *ui)
366{
367 struct addr_location al;
368
Arnaldo Carvalho de Melobb871a92014-10-23 12:50:25 -0300369 thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER,
Adrian Hunter326f59b2013-08-08 14:32:27 +0300370 MAP__FUNCTION, ip, &al);
Jiri Olsa0ddf5242016-01-07 10:14:01 +0100371 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 }
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200380 return al.map;
381}
382
383static int
384find_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;
Rabin Vincent8eac1d52015-09-27 20:37:57 +0200391 int ret = -EINVAL;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200392
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
Jean Pihetab255e72013-09-26 12:36:38 +0100399 /* 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;
Stefano Sanfilippoeac05af2016-10-13 03:59:39 -0700406 di.u.rti.segbase = map->start + segbase - map->pgoff;
407 di.u.rti.table_data = map->start + table_data - map->pgoff;
Jean Pihetab255e72013-09-26 12:36:38 +0100408 di.u.rti.table_len = fde_count * sizeof(struct table_entry)
409 / sizeof(unw_word_t);
Rabin Vincent8eac1d52015-09-27 20:37:57 +0200410 ret = dwarf_search_unwind_table(as, ip, &di, pi,
411 need_unwind_info, arg);
Jean Pihetab255e72013-09-26 12:36:38 +0100412 }
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200413
Jean Pihetab255e72013-09-26 12:36:38 +0100414#ifndef NO_LIBUNWIND_DEBUG_FRAME
415 /* Check the .debug_frame section for unwinding info */
Rabin Vincent8eac1d52015-09-27 20:37:57 +0200416 if (ret < 0 &&
417 !read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) {
Namhyung Kim4bb11d02015-05-21 01:03:41 +0900418 int fd = dso__data_get_fd(map->dso, ui->machine);
Wang Nanb93b0962015-01-14 10:36:47 +0800419 int is_exec = elf_is_exec(fd, map->dso->name);
420 unw_word_t base = is_exec ? 0 : map->start;
Rabin Vincent7ed49152015-10-29 08:49:36 +0100421 const char *symfile;
Wang Nanb93b0962015-01-14 10:36:47 +0800422
Namhyung Kim4bb11d02015-05-21 01:03:41 +0900423 if (fd >= 0)
Hou Pengyangf0058132015-06-16 11:16:35 +0000424 dso__data_put_fd(map->dso);
Namhyung Kim4bb11d02015-05-21 01:03:41 +0900425
Rabin Vincent7ed49152015-10-29 08:49:36 +0100426 symfile = map->dso->symsrc_filename ?: map->dso->name;
427
Jean Pihetab255e72013-09-26 12:36:38 +0100428 memset(&di, 0, sizeof(di));
Rabin Vincent7ed49152015-10-29 08:49:36 +0100429 if (dwarf_find_debug_frame(0, &di, ip, base, symfile,
Jean Pihetd11416e2013-12-16 17:43:14 +0100430 map->start, map->end))
431 return dwarf_search_unwind_table(as, ip, &di, pi,
432 need_unwind_info, arg);
Jean Pihetab255e72013-09-26 12:36:38 +0100433 }
434#endif
435
Rabin Vincent8eac1d52015-09-27 20:37:57 +0200436 return ret;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200437}
438
Irina Tirdea1d037ca2012-09-11 01:15:03 +0300439static 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)
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200444{
445 pr_err("unwind: access_fpreg unsupported\n");
446 return -UNW_EINVAL;
447}
448
Irina Tirdea1d037ca2012-09-11 01:15:03 +0300449static 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)
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200452{
453 return -UNW_ENOINFO;
454}
455
Irina Tirdea1d037ca2012-09-11 01:15:03 +0300456static int resume(unw_addr_space_t __maybe_unused as,
457 unw_cursor_t __maybe_unused *cu,
458 void __maybe_unused *arg)
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200459{
460 pr_err("unwind: resume unsupported\n");
461 return -UNW_EINVAL;
462}
463
464static int
Irina Tirdea1d037ca2012-09-11 01:15:03 +0300465get_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)
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200469{
470 pr_err("unwind: get_proc_name unsupported\n");
471 return -UNW_EINVAL;
472}
473
474static int access_dso_mem(struct unwind_info *ui, unw_word_t addr,
475 unw_word_t *data)
476{
Jiri Olsaf22ed822016-01-07 10:14:00 +0100477 struct map *map;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200478 ssize_t size;
479
Jiri Olsaf22ed822016-01-07 10:14:00 +0100480 map = find_map(addr, ui);
481 if (!map) {
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200482 pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
483 return -1;
484 }
485
Jiri Olsaf22ed822016-01-07 10:14:00 +0100486 if (!map->dso)
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200487 return -1;
488
Jiri Olsaf22ed822016-01-07 10:14:00 +0100489 size = dso__data_read_addr(map->dso, map, ui->machine,
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200490 addr, (u8 *) data, sizeof(*data));
491
492 return !(size == sizeof(*data));
493}
494
Irina Tirdea1d037ca2012-09-11 01:15:03 +0300495static int access_mem(unw_addr_space_t __maybe_unused as,
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200496 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;
Jiri Olsac9b951c2014-01-07 13:47:29 +0100501 u64 start, end;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200502 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
He Kuang78ff1d62016-06-22 06:57:02 +0000511 ret = perf_reg_value(&start, &ui->sample->user_regs,
512 LIBUNWIND__ARCH_REG_SP);
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200513 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) {
Jiri Olsac9b951c2014-01-07 13:47:29 +0100525 pr_debug("unwind: access_mem %p not inside range"
526 " 0x%" PRIx64 "-0x%" PRIx64 "\n",
Rabin Vincent186c6cf2015-09-27 20:37:55 +0200527 (void *) (uintptr_t) addr, start, end);
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200528 *valp = 0;
529 return ret;
530 }
531 return 0;
532 }
533
534 offset = addr - start;
535 *valp = *(unw_word_t *)&stack->data[offset];
Jiri Olsac9b951c2014-01-07 13:47:29 +0100536 pr_debug("unwind: access_mem addr %p val %lx, offset %d\n",
Rabin Vincent186c6cf2015-09-27 20:37:55 +0200537 (void *) (uintptr_t) addr, (unsigned long)*valp, offset);
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200538 return 0;
539}
540
Irina Tirdea1d037ca2012-09-11 01:15:03 +0300541static int access_reg(unw_addr_space_t __maybe_unused as,
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200542 unw_regnum_t regnum, unw_word_t *valp,
543 int __write, void *arg)
544{
545 struct unwind_info *ui = arg;
546 int id, ret;
Jiri Olsac9b951c2014-01-07 13:47:29 +0100547 u64 val;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200548
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
He Kuangeeb118c2016-06-03 03:33:20 +0000560 id = LIBUNWIND__ARCH_REG_ID(regnum);
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200561 if (id < 0)
562 return -EINVAL;
563
Jiri Olsac9b951c2014-01-07 13:47:29 +0100564 ret = perf_reg_value(&val, &ui->sample->user_regs, id);
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200565 if (ret) {
566 pr_err("unwind: can't read reg %d\n", regnum);
567 return ret;
568 }
569
Jiri Olsac9b951c2014-01-07 13:47:29 +0100570 *valp = (unw_word_t) val;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200571 pr_debug("unwind: reg %d, val %lx\n", regnum, (unsigned long)*valp);
572 return 0;
573}
574
Irina Tirdea1d037ca2012-09-11 01:15:03 +0300575static void put_unwind_info(unw_addr_space_t __maybe_unused as,
576 unw_proc_info_t *pi __maybe_unused,
577 void *arg __maybe_unused)
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200578{
579 pr_debug("unwind: put_unwind_info called\n");
580}
581
Arnaldo Carvalho de Melobb871a92014-10-23 12:50:25 -0300582static int entry(u64 ip, struct thread *thread,
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200583 unwind_entry_cb_t cb, void *arg)
584{
585 struct unwind_entry e;
586 struct addr_location al;
587
Arnaldo Carvalho de Melobb871a92014-10-23 12:50:25 -0300588 thread__find_addr_location(thread, PERF_RECORD_MISC_USER,
Adrian Hunter61710bd2013-08-08 14:32:26 +0300589 MAP__FUNCTION, ip, &al);
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200590
Milian Wolff67540752016-08-16 17:39:26 +0200591 e.ip = al.addr;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200592 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
603static 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
620static 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
He Kuangf83c0412016-06-03 03:33:12 +0000631static int _unwind__prepare_access(struct thread *thread)
Namhyung Kim66f066d82014-10-06 09:46:00 +0900632{
Namhyung Kim66f066d82014-10-06 09:46:00 +0900633 if (callchain_param.record_mode != CALLCHAIN_DWARF)
634 return 0;
635
Jiri Olsae583d702016-04-07 09:11:12 +0200636 thread->addr_space = unw_create_addr_space(&accessors, 0);
637 if (!thread->addr_space) {
Namhyung Kim66f066d82014-10-06 09:46:00 +0900638 pr_err("unwind: Can't create unwind address space.\n");
639 return -ENOMEM;
640 }
641
Jiri Olsae583d702016-04-07 09:11:12 +0200642 unw_set_caching_policy(thread->addr_space, UNW_CACHE_GLOBAL);
Namhyung Kim66f066d82014-10-06 09:46:00 +0900643 return 0;
644}
645
He Kuangf83c0412016-06-03 03:33:12 +0000646static void _unwind__flush_access(struct thread *thread)
Namhyung Kim380b5142014-10-06 09:46:01 +0900647{
Namhyung Kim380b5142014-10-06 09:46:01 +0900648 if (callchain_param.record_mode != CALLCHAIN_DWARF)
649 return;
650
Jiri Olsae583d702016-04-07 09:11:12 +0200651 unw_flush_cache(thread->addr_space, 0, 0);
Namhyung Kim380b5142014-10-06 09:46:01 +0900652}
653
He Kuangf83c0412016-06-03 03:33:12 +0000654static void _unwind__finish_access(struct thread *thread)
Namhyung Kim66f066d82014-10-06 09:46:00 +0900655{
Namhyung Kim66f066d82014-10-06 09:46:00 +0900656 if (callchain_param.record_mode != CALLCHAIN_DWARF)
657 return;
658
Jiri Olsae583d702016-04-07 09:11:12 +0200659 unw_destroy_addr_space(thread->addr_space);
Namhyung Kim66f066d82014-10-06 09:46:00 +0900660}
661
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200662static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
Arnaldo Carvalho de Melo37676af2013-11-13 17:40:36 -0300663 void *arg, int max_stack)
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200664{
Jiri Olsab26b2182015-11-17 16:05:37 +0100665 u64 val;
Jiri Olsacb1dc222015-11-18 08:52:47 +0100666 unw_word_t ips[max_stack];
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200667 unw_addr_space_t addr_space;
668 unw_cursor_t c;
Jiri Olsacb1dc222015-11-18 08:52:47 +0100669 int ret, i = 0;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200670
He Kuang78ff1d62016-06-22 06:57:02 +0000671 ret = perf_reg_value(&val, &ui->sample->user_regs,
672 LIBUNWIND__ARCH_REG_IP);
Jiri Olsab26b2182015-11-17 16:05:37 +0100673 if (ret)
674 return ret;
675
Jiri Olsacb1dc222015-11-18 08:52:47 +0100676 ips[i++] = (unw_word_t) val;
Jiri Olsab26b2182015-11-17 16:05:37 +0100677
Jiri Olsacb1dc222015-11-18 08:52:47 +0100678 /*
679 * If we need more than one entry, do the DWARF
680 * unwind itself.
681 */
682 if (max_stack - 1 > 0) {
Jiri Olsae583d702016-04-07 09:11:12 +0200683 WARN_ONCE(!ui->thread, "WARNING: ui->thread is NULL");
684 addr_space = ui->thread->addr_space;
685
Jiri Olsacb1dc222015-11-18 08:52:47 +0100686 if (addr_space == NULL)
687 return -1;
Jiri Olsab26b2182015-11-17 16:05:37 +0100688
Jiri Olsacb1dc222015-11-18 08:52:47 +0100689 ret = unw_init_remote(&c, addr_space, ui);
690 if (ret)
691 display_error(ret);
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200692
Jiri Olsacb1dc222015-11-18 08:52:47 +0100693 while (!ret && (unw_step(&c) > 0) && i < max_stack) {
694 unw_get_reg(&c, UNW_REG_IP, &ips[i]);
695 ++i;
696 }
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200697
Jiri Olsacb1dc222015-11-18 08:52:47 +0100698 max_stack = i;
699 }
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200700
Jiri Olsacb1dc222015-11-18 08:52:47 +0100701 /*
702 * Display what we got based on the order setup.
703 */
704 for (i = 0; i < max_stack && !ret; i++) {
705 int j = i;
706
707 if (callchain_param.order == ORDER_CALLER)
708 j = max_stack - i - 1;
709 ret = ips[j] ? entry(ips[j], ui->thread, cb, arg) : 0;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200710 }
711
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200712 return ret;
713}
714
He Kuangf83c0412016-06-03 03:33:12 +0000715static int _unwind__get_entries(unwind_entry_cb_t cb, void *arg,
Arnaldo Carvalho de Melodd8c17a2014-10-23 16:42:19 -0300716 struct thread *thread,
Jiri Olsa352ea452014-01-07 13:47:25 +0100717 struct perf_sample *data, int max_stack)
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200718{
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200719 struct unwind_info ui = {
720 .sample = data,
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200721 .thread = thread,
Arnaldo Carvalho de Melodd8c17a2014-10-23 16:42:19 -0300722 .machine = thread->mg->machine,
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200723 };
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200724
725 if (!data->user_regs.regs)
726 return -EINVAL;
727
Jiri Olsab26b2182015-11-17 16:05:37 +0100728 if (max_stack <= 0)
729 return -EINVAL;
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200730
Jiri Olsab26b2182015-11-17 16:05:37 +0100731 return get_entries(&ui, cb, arg, max_stack);
Jiri Olsa71ad0f52012-08-07 15:20:46 +0200732}
He Kuangf83c0412016-06-03 03:33:12 +0000733
734static struct unwind_libunwind_ops
735_unwind_libunwind_ops = {
736 .prepare_access = _unwind__prepare_access,
737 .flush_access = _unwind__flush_access,
738 .finish_access = _unwind__finish_access,
739 .get_entries = _unwind__get_entries,
740};
741
He Kuang19473e72016-06-03 03:33:21 +0000742#ifndef REMOTE_UNWIND_LIBUNWIND
He Kuangf83c0412016-06-03 03:33:12 +0000743struct unwind_libunwind_ops *
744local_unwind_libunwind_ops = &_unwind_libunwind_ops;
He Kuang19473e72016-06-03 03:33:21 +0000745#endif