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reset: Restrict RESET_HSDK to ARC_SOC_HSDK or COMPILE_TEST
[mirror_ubuntu-bionic-kernel.git] / tools / perf / util / symbol-elf.c
1 #include <fcntl.h>
2 #include <stdio.h>
3 #include <errno.h>
4 #include <string.h>
5 #include <unistd.h>
6 #include <inttypes.h>
7
8 #include "symbol.h"
9 #include "demangle-java.h"
10 #include "demangle-rust.h"
11 #include "machine.h"
12 #include "vdso.h"
13 #include "debug.h"
14 #include "sane_ctype.h"
15 #include <symbol/kallsyms.h>
16
17 #ifndef EM_AARCH64
18 #define EM_AARCH64 183 /* ARM 64 bit */
19 #endif
20
21 typedef Elf64_Nhdr GElf_Nhdr;
22
23 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
24 extern char *cplus_demangle(const char *, int);
25
26 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
27 {
28 return cplus_demangle(c, i);
29 }
30 #else
31 #ifdef NO_DEMANGLE
32 static inline char *bfd_demangle(void __maybe_unused *v,
33 const char __maybe_unused *c,
34 int __maybe_unused i)
35 {
36 return NULL;
37 }
38 #else
39 #define PACKAGE 'perf'
40 #include <bfd.h>
41 #endif
42 #endif
43
44 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
45 static int elf_getphdrnum(Elf *elf, size_t *dst)
46 {
47 GElf_Ehdr gehdr;
48 GElf_Ehdr *ehdr;
49
50 ehdr = gelf_getehdr(elf, &gehdr);
51 if (!ehdr)
52 return -1;
53
54 *dst = ehdr->e_phnum;
55
56 return 0;
57 }
58 #endif
59
60 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
61 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
62 {
63 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
64 return -1;
65 }
66 #endif
67
68 #ifndef NT_GNU_BUILD_ID
69 #define NT_GNU_BUILD_ID 3
70 #endif
71
72 /**
73 * elf_symtab__for_each_symbol - iterate thru all the symbols
74 *
75 * @syms: struct elf_symtab instance to iterate
76 * @idx: uint32_t idx
77 * @sym: GElf_Sym iterator
78 */
79 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
80 for (idx = 0, gelf_getsym(syms, idx, &sym);\
81 idx < nr_syms; \
82 idx++, gelf_getsym(syms, idx, &sym))
83
84 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
85 {
86 return GELF_ST_TYPE(sym->st_info);
87 }
88
89 #ifndef STT_GNU_IFUNC
90 #define STT_GNU_IFUNC 10
91 #endif
92
93 static inline int elf_sym__is_function(const GElf_Sym *sym)
94 {
95 return (elf_sym__type(sym) == STT_FUNC ||
96 elf_sym__type(sym) == STT_GNU_IFUNC) &&
97 sym->st_name != 0 &&
98 sym->st_shndx != SHN_UNDEF;
99 }
100
101 static inline bool elf_sym__is_object(const GElf_Sym *sym)
102 {
103 return elf_sym__type(sym) == STT_OBJECT &&
104 sym->st_name != 0 &&
105 sym->st_shndx != SHN_UNDEF;
106 }
107
108 static inline int elf_sym__is_label(const GElf_Sym *sym)
109 {
110 return elf_sym__type(sym) == STT_NOTYPE &&
111 sym->st_name != 0 &&
112 sym->st_shndx != SHN_UNDEF &&
113 sym->st_shndx != SHN_ABS;
114 }
115
116 static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
117 {
118 switch (type) {
119 case MAP__FUNCTION:
120 return elf_sym__is_function(sym);
121 case MAP__VARIABLE:
122 return elf_sym__is_object(sym);
123 default:
124 return false;
125 }
126 }
127
128 static inline const char *elf_sym__name(const GElf_Sym *sym,
129 const Elf_Data *symstrs)
130 {
131 return symstrs->d_buf + sym->st_name;
132 }
133
134 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
135 const Elf_Data *secstrs)
136 {
137 return secstrs->d_buf + shdr->sh_name;
138 }
139
140 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
141 const Elf_Data *secstrs)
142 {
143 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
144 }
145
146 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
147 const Elf_Data *secstrs)
148 {
149 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
150 }
151
152 static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
153 enum map_type type)
154 {
155 switch (type) {
156 case MAP__FUNCTION:
157 return elf_sec__is_text(shdr, secstrs);
158 case MAP__VARIABLE:
159 return elf_sec__is_data(shdr, secstrs);
160 default:
161 return false;
162 }
163 }
164
165 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
166 {
167 Elf_Scn *sec = NULL;
168 GElf_Shdr shdr;
169 size_t cnt = 1;
170
171 while ((sec = elf_nextscn(elf, sec)) != NULL) {
172 gelf_getshdr(sec, &shdr);
173
174 if ((addr >= shdr.sh_addr) &&
175 (addr < (shdr.sh_addr + shdr.sh_size)))
176 return cnt;
177
178 ++cnt;
179 }
180
181 return -1;
182 }
183
184 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
185 GElf_Shdr *shp, const char *name, size_t *idx)
186 {
187 Elf_Scn *sec = NULL;
188 size_t cnt = 1;
189
190 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
191 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
192 return NULL;
193
194 while ((sec = elf_nextscn(elf, sec)) != NULL) {
195 char *str;
196
197 gelf_getshdr(sec, shp);
198 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
199 if (str && !strcmp(name, str)) {
200 if (idx)
201 *idx = cnt;
202 return sec;
203 }
204 ++cnt;
205 }
206
207 return NULL;
208 }
209
210 static bool want_demangle(bool is_kernel_sym)
211 {
212 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
213 }
214
215 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
216 {
217 int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
218 char *demangled = NULL;
219
220 /*
221 * We need to figure out if the object was created from C++ sources
222 * DWARF DW_compile_unit has this, but we don't always have access
223 * to it...
224 */
225 if (!want_demangle(dso->kernel || kmodule))
226 return demangled;
227
228 demangled = bfd_demangle(NULL, elf_name, demangle_flags);
229 if (demangled == NULL)
230 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
231 else if (rust_is_mangled(demangled))
232 /*
233 * Input to Rust demangling is the BFD-demangled
234 * name which it Rust-demangles in place.
235 */
236 rust_demangle_sym(demangled);
237
238 return demangled;
239 }
240
241 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
242 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
243 idx < nr_entries; \
244 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
245
246 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
247 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
248 idx < nr_entries; \
249 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
250
251 /*
252 * We need to check if we have a .dynsym, so that we can handle the
253 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
254 * .dynsym or .symtab).
255 * And always look at the original dso, not at debuginfo packages, that
256 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
257 */
258 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map)
259 {
260 uint32_t nr_rel_entries, idx;
261 GElf_Sym sym;
262 u64 plt_offset, plt_header_size, plt_entry_size;
263 GElf_Shdr shdr_plt;
264 struct symbol *f;
265 GElf_Shdr shdr_rel_plt, shdr_dynsym;
266 Elf_Data *reldata, *syms, *symstrs;
267 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
268 size_t dynsym_idx;
269 GElf_Ehdr ehdr;
270 char sympltname[1024];
271 Elf *elf;
272 int nr = 0, symidx, err = 0;
273
274 if (!ss->dynsym)
275 return 0;
276
277 elf = ss->elf;
278 ehdr = ss->ehdr;
279
280 scn_dynsym = ss->dynsym;
281 shdr_dynsym = ss->dynshdr;
282 dynsym_idx = ss->dynsym_idx;
283
284 if (scn_dynsym == NULL)
285 goto out_elf_end;
286
287 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
288 ".rela.plt", NULL);
289 if (scn_plt_rel == NULL) {
290 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
291 ".rel.plt", NULL);
292 if (scn_plt_rel == NULL)
293 goto out_elf_end;
294 }
295
296 err = -1;
297
298 if (shdr_rel_plt.sh_link != dynsym_idx)
299 goto out_elf_end;
300
301 if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
302 goto out_elf_end;
303
304 /*
305 * Fetch the relocation section to find the idxes to the GOT
306 * and the symbols in the .dynsym they refer to.
307 */
308 reldata = elf_getdata(scn_plt_rel, NULL);
309 if (reldata == NULL)
310 goto out_elf_end;
311
312 syms = elf_getdata(scn_dynsym, NULL);
313 if (syms == NULL)
314 goto out_elf_end;
315
316 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
317 if (scn_symstrs == NULL)
318 goto out_elf_end;
319
320 symstrs = elf_getdata(scn_symstrs, NULL);
321 if (symstrs == NULL)
322 goto out_elf_end;
323
324 if (symstrs->d_size == 0)
325 goto out_elf_end;
326
327 nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
328 plt_offset = shdr_plt.sh_offset;
329 switch (ehdr.e_machine) {
330 case EM_ARM:
331 plt_header_size = 20;
332 plt_entry_size = 12;
333 break;
334
335 case EM_AARCH64:
336 plt_header_size = 32;
337 plt_entry_size = 16;
338 break;
339
340 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/sparc/xtensa need to be checked */
341 plt_header_size = shdr_plt.sh_entsize;
342 plt_entry_size = shdr_plt.sh_entsize;
343 break;
344 }
345 plt_offset += plt_header_size;
346
347 if (shdr_rel_plt.sh_type == SHT_RELA) {
348 GElf_Rela pos_mem, *pos;
349
350 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
351 nr_rel_entries) {
352 const char *elf_name = NULL;
353 char *demangled = NULL;
354 symidx = GELF_R_SYM(pos->r_info);
355 gelf_getsym(syms, symidx, &sym);
356
357 elf_name = elf_sym__name(&sym, symstrs);
358 demangled = demangle_sym(dso, 0, elf_name);
359 if (demangled != NULL)
360 elf_name = demangled;
361 snprintf(sympltname, sizeof(sympltname),
362 "%s@plt", elf_name);
363 free(demangled);
364
365 f = symbol__new(plt_offset, plt_entry_size,
366 STB_GLOBAL, sympltname);
367 if (!f)
368 goto out_elf_end;
369
370 plt_offset += plt_entry_size;
371 symbols__insert(&dso->symbols[map->type], f);
372 ++nr;
373 }
374 } else if (shdr_rel_plt.sh_type == SHT_REL) {
375 GElf_Rel pos_mem, *pos;
376 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
377 nr_rel_entries) {
378 const char *elf_name = NULL;
379 char *demangled = NULL;
380 symidx = GELF_R_SYM(pos->r_info);
381 gelf_getsym(syms, symidx, &sym);
382
383 elf_name = elf_sym__name(&sym, symstrs);
384 demangled = demangle_sym(dso, 0, elf_name);
385 if (demangled != NULL)
386 elf_name = demangled;
387 snprintf(sympltname, sizeof(sympltname),
388 "%s@plt", elf_name);
389 free(demangled);
390
391 f = symbol__new(plt_offset, plt_entry_size,
392 STB_GLOBAL, sympltname);
393 if (!f)
394 goto out_elf_end;
395
396 plt_offset += plt_entry_size;
397 symbols__insert(&dso->symbols[map->type], f);
398 ++nr;
399 }
400 }
401
402 err = 0;
403 out_elf_end:
404 if (err == 0)
405 return nr;
406 pr_debug("%s: problems reading %s PLT info.\n",
407 __func__, dso->long_name);
408 return 0;
409 }
410
411 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
412 {
413 return demangle_sym(dso, kmodule, elf_name);
414 }
415
416 /*
417 * Align offset to 4 bytes as needed for note name and descriptor data.
418 */
419 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
420
421 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
422 {
423 int err = -1;
424 GElf_Ehdr ehdr;
425 GElf_Shdr shdr;
426 Elf_Data *data;
427 Elf_Scn *sec;
428 Elf_Kind ek;
429 void *ptr;
430
431 if (size < BUILD_ID_SIZE)
432 goto out;
433
434 ek = elf_kind(elf);
435 if (ek != ELF_K_ELF)
436 goto out;
437
438 if (gelf_getehdr(elf, &ehdr) == NULL) {
439 pr_err("%s: cannot get elf header.\n", __func__);
440 goto out;
441 }
442
443 /*
444 * Check following sections for notes:
445 * '.note.gnu.build-id'
446 * '.notes'
447 * '.note' (VDSO specific)
448 */
449 do {
450 sec = elf_section_by_name(elf, &ehdr, &shdr,
451 ".note.gnu.build-id", NULL);
452 if (sec)
453 break;
454
455 sec = elf_section_by_name(elf, &ehdr, &shdr,
456 ".notes", NULL);
457 if (sec)
458 break;
459
460 sec = elf_section_by_name(elf, &ehdr, &shdr,
461 ".note", NULL);
462 if (sec)
463 break;
464
465 return err;
466
467 } while (0);
468
469 data = elf_getdata(sec, NULL);
470 if (data == NULL)
471 goto out;
472
473 ptr = data->d_buf;
474 while (ptr < (data->d_buf + data->d_size)) {
475 GElf_Nhdr *nhdr = ptr;
476 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
477 descsz = NOTE_ALIGN(nhdr->n_descsz);
478 const char *name;
479
480 ptr += sizeof(*nhdr);
481 name = ptr;
482 ptr += namesz;
483 if (nhdr->n_type == NT_GNU_BUILD_ID &&
484 nhdr->n_namesz == sizeof("GNU")) {
485 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
486 size_t sz = min(size, descsz);
487 memcpy(bf, ptr, sz);
488 memset(bf + sz, 0, size - sz);
489 err = descsz;
490 break;
491 }
492 }
493 ptr += descsz;
494 }
495
496 out:
497 return err;
498 }
499
500 int filename__read_build_id(const char *filename, void *bf, size_t size)
501 {
502 int fd, err = -1;
503 Elf *elf;
504
505 if (size < BUILD_ID_SIZE)
506 goto out;
507
508 fd = open(filename, O_RDONLY);
509 if (fd < 0)
510 goto out;
511
512 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
513 if (elf == NULL) {
514 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
515 goto out_close;
516 }
517
518 err = elf_read_build_id(elf, bf, size);
519
520 elf_end(elf);
521 out_close:
522 close(fd);
523 out:
524 return err;
525 }
526
527 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
528 {
529 int fd, err = -1;
530
531 if (size < BUILD_ID_SIZE)
532 goto out;
533
534 fd = open(filename, O_RDONLY);
535 if (fd < 0)
536 goto out;
537
538 while (1) {
539 char bf[BUFSIZ];
540 GElf_Nhdr nhdr;
541 size_t namesz, descsz;
542
543 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
544 break;
545
546 namesz = NOTE_ALIGN(nhdr.n_namesz);
547 descsz = NOTE_ALIGN(nhdr.n_descsz);
548 if (nhdr.n_type == NT_GNU_BUILD_ID &&
549 nhdr.n_namesz == sizeof("GNU")) {
550 if (read(fd, bf, namesz) != (ssize_t)namesz)
551 break;
552 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
553 size_t sz = min(descsz, size);
554 if (read(fd, build_id, sz) == (ssize_t)sz) {
555 memset(build_id + sz, 0, size - sz);
556 err = 0;
557 break;
558 }
559 } else if (read(fd, bf, descsz) != (ssize_t)descsz)
560 break;
561 } else {
562 int n = namesz + descsz;
563
564 if (n > (int)sizeof(bf)) {
565 n = sizeof(bf);
566 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
567 __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
568 }
569 if (read(fd, bf, n) != n)
570 break;
571 }
572 }
573 close(fd);
574 out:
575 return err;
576 }
577
578 int filename__read_debuglink(const char *filename, char *debuglink,
579 size_t size)
580 {
581 int fd, err = -1;
582 Elf *elf;
583 GElf_Ehdr ehdr;
584 GElf_Shdr shdr;
585 Elf_Data *data;
586 Elf_Scn *sec;
587 Elf_Kind ek;
588
589 fd = open(filename, O_RDONLY);
590 if (fd < 0)
591 goto out;
592
593 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
594 if (elf == NULL) {
595 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
596 goto out_close;
597 }
598
599 ek = elf_kind(elf);
600 if (ek != ELF_K_ELF)
601 goto out_elf_end;
602
603 if (gelf_getehdr(elf, &ehdr) == NULL) {
604 pr_err("%s: cannot get elf header.\n", __func__);
605 goto out_elf_end;
606 }
607
608 sec = elf_section_by_name(elf, &ehdr, &shdr,
609 ".gnu_debuglink", NULL);
610 if (sec == NULL)
611 goto out_elf_end;
612
613 data = elf_getdata(sec, NULL);
614 if (data == NULL)
615 goto out_elf_end;
616
617 /* the start of this section is a zero-terminated string */
618 strncpy(debuglink, data->d_buf, size);
619
620 err = 0;
621
622 out_elf_end:
623 elf_end(elf);
624 out_close:
625 close(fd);
626 out:
627 return err;
628 }
629
630 static int dso__swap_init(struct dso *dso, unsigned char eidata)
631 {
632 static unsigned int const endian = 1;
633
634 dso->needs_swap = DSO_SWAP__NO;
635
636 switch (eidata) {
637 case ELFDATA2LSB:
638 /* We are big endian, DSO is little endian. */
639 if (*(unsigned char const *)&endian != 1)
640 dso->needs_swap = DSO_SWAP__YES;
641 break;
642
643 case ELFDATA2MSB:
644 /* We are little endian, DSO is big endian. */
645 if (*(unsigned char const *)&endian != 0)
646 dso->needs_swap = DSO_SWAP__YES;
647 break;
648
649 default:
650 pr_err("unrecognized DSO data encoding %d\n", eidata);
651 return -EINVAL;
652 }
653
654 return 0;
655 }
656
657 bool symsrc__possibly_runtime(struct symsrc *ss)
658 {
659 return ss->dynsym || ss->opdsec;
660 }
661
662 bool symsrc__has_symtab(struct symsrc *ss)
663 {
664 return ss->symtab != NULL;
665 }
666
667 void symsrc__destroy(struct symsrc *ss)
668 {
669 zfree(&ss->name);
670 elf_end(ss->elf);
671 close(ss->fd);
672 }
673
674 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
675 {
676 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
677 }
678
679 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
680 enum dso_binary_type type)
681 {
682 int err = -1;
683 GElf_Ehdr ehdr;
684 Elf *elf;
685 int fd;
686
687 if (dso__needs_decompress(dso)) {
688 fd = dso__decompress_kmodule_fd(dso, name);
689 if (fd < 0)
690 return -1;
691
692 type = dso->symtab_type;
693 } else {
694 fd = open(name, O_RDONLY);
695 if (fd < 0) {
696 dso->load_errno = errno;
697 return -1;
698 }
699 }
700
701 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
702 if (elf == NULL) {
703 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
704 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
705 goto out_close;
706 }
707
708 if (gelf_getehdr(elf, &ehdr) == NULL) {
709 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
710 pr_debug("%s: cannot get elf header.\n", __func__);
711 goto out_elf_end;
712 }
713
714 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
715 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
716 goto out_elf_end;
717 }
718
719 /* Always reject images with a mismatched build-id: */
720 if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
721 u8 build_id[BUILD_ID_SIZE];
722
723 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
724 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
725 goto out_elf_end;
726 }
727
728 if (!dso__build_id_equal(dso, build_id)) {
729 pr_debug("%s: build id mismatch for %s.\n", __func__, name);
730 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
731 goto out_elf_end;
732 }
733 }
734
735 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
736
737 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
738 NULL);
739 if (ss->symshdr.sh_type != SHT_SYMTAB)
740 ss->symtab = NULL;
741
742 ss->dynsym_idx = 0;
743 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
744 &ss->dynsym_idx);
745 if (ss->dynshdr.sh_type != SHT_DYNSYM)
746 ss->dynsym = NULL;
747
748 ss->opdidx = 0;
749 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
750 &ss->opdidx);
751 if (ss->opdshdr.sh_type != SHT_PROGBITS)
752 ss->opdsec = NULL;
753
754 if (dso->kernel == DSO_TYPE_USER)
755 ss->adjust_symbols = true;
756 else
757 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
758
759 ss->name = strdup(name);
760 if (!ss->name) {
761 dso->load_errno = errno;
762 goto out_elf_end;
763 }
764
765 ss->elf = elf;
766 ss->fd = fd;
767 ss->ehdr = ehdr;
768 ss->type = type;
769
770 return 0;
771
772 out_elf_end:
773 elf_end(elf);
774 out_close:
775 close(fd);
776 return err;
777 }
778
779 /**
780 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
781 * @kmap: kernel maps and relocation reference symbol
782 *
783 * This function returns %true if we are dealing with the kernel maps and the
784 * relocation reference symbol has not yet been found. Otherwise %false is
785 * returned.
786 */
787 static bool ref_reloc_sym_not_found(struct kmap *kmap)
788 {
789 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
790 !kmap->ref_reloc_sym->unrelocated_addr;
791 }
792
793 /**
794 * ref_reloc - kernel relocation offset.
795 * @kmap: kernel maps and relocation reference symbol
796 *
797 * This function returns the offset of kernel addresses as determined by using
798 * the relocation reference symbol i.e. if the kernel has not been relocated
799 * then the return value is zero.
800 */
801 static u64 ref_reloc(struct kmap *kmap)
802 {
803 if (kmap && kmap->ref_reloc_sym &&
804 kmap->ref_reloc_sym->unrelocated_addr)
805 return kmap->ref_reloc_sym->addr -
806 kmap->ref_reloc_sym->unrelocated_addr;
807 return 0;
808 }
809
810 void __weak arch__sym_update(struct symbol *s __maybe_unused,
811 GElf_Sym *sym __maybe_unused) { }
812
813 void __weak arch__adjust_sym_map_offset(GElf_Sym *sym, GElf_Shdr *shdr,
814 struct map *map __maybe_unused)
815 {
816 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
817 }
818
819 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
820 struct symsrc *runtime_ss, int kmodule)
821 {
822 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
823 struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
824 struct map *curr_map = map;
825 struct dso *curr_dso = dso;
826 Elf_Data *symstrs, *secstrs;
827 uint32_t nr_syms;
828 int err = -1;
829 uint32_t idx;
830 GElf_Ehdr ehdr;
831 GElf_Shdr shdr;
832 GElf_Shdr tshdr;
833 Elf_Data *syms, *opddata = NULL;
834 GElf_Sym sym;
835 Elf_Scn *sec, *sec_strndx;
836 Elf *elf;
837 int nr = 0;
838 bool remap_kernel = false, adjust_kernel_syms = false;
839
840 if (kmap && !kmaps)
841 return -1;
842
843 dso->symtab_type = syms_ss->type;
844 dso->is_64_bit = syms_ss->is_64_bit;
845 dso->rel = syms_ss->ehdr.e_type == ET_REL;
846
847 /*
848 * Modules may already have symbols from kallsyms, but those symbols
849 * have the wrong values for the dso maps, so remove them.
850 */
851 if (kmodule && syms_ss->symtab)
852 symbols__delete(&dso->symbols[map->type]);
853
854 if (!syms_ss->symtab) {
855 /*
856 * If the vmlinux is stripped, fail so we will fall back
857 * to using kallsyms. The vmlinux runtime symbols aren't
858 * of much use.
859 */
860 if (dso->kernel)
861 goto out_elf_end;
862
863 syms_ss->symtab = syms_ss->dynsym;
864 syms_ss->symshdr = syms_ss->dynshdr;
865 }
866
867 elf = syms_ss->elf;
868 ehdr = syms_ss->ehdr;
869 sec = syms_ss->symtab;
870 shdr = syms_ss->symshdr;
871
872 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
873 ".text", NULL))
874 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
875
876 if (runtime_ss->opdsec)
877 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
878
879 syms = elf_getdata(sec, NULL);
880 if (syms == NULL)
881 goto out_elf_end;
882
883 sec = elf_getscn(elf, shdr.sh_link);
884 if (sec == NULL)
885 goto out_elf_end;
886
887 symstrs = elf_getdata(sec, NULL);
888 if (symstrs == NULL)
889 goto out_elf_end;
890
891 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
892 if (sec_strndx == NULL)
893 goto out_elf_end;
894
895 secstrs = elf_getdata(sec_strndx, NULL);
896 if (secstrs == NULL)
897 goto out_elf_end;
898
899 nr_syms = shdr.sh_size / shdr.sh_entsize;
900
901 memset(&sym, 0, sizeof(sym));
902
903 /*
904 * The kernel relocation symbol is needed in advance in order to adjust
905 * kernel maps correctly.
906 */
907 if (ref_reloc_sym_not_found(kmap)) {
908 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
909 const char *elf_name = elf_sym__name(&sym, symstrs);
910
911 if (strcmp(elf_name, kmap->ref_reloc_sym->name))
912 continue;
913 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
914 map->reloc = kmap->ref_reloc_sym->addr -
915 kmap->ref_reloc_sym->unrelocated_addr;
916 break;
917 }
918 }
919
920 /*
921 * Handle any relocation of vdso necessary because older kernels
922 * attempted to prelink vdso to its virtual address.
923 */
924 if (dso__is_vdso(dso))
925 map->reloc = map->start - dso->text_offset;
926
927 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
928 /*
929 * Initial kernel and module mappings do not map to the dso. For
930 * function mappings, flag the fixups.
931 */
932 if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
933 remap_kernel = true;
934 adjust_kernel_syms = dso->adjust_symbols;
935 }
936 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
937 struct symbol *f;
938 const char *elf_name = elf_sym__name(&sym, symstrs);
939 char *demangled = NULL;
940 int is_label = elf_sym__is_label(&sym);
941 const char *section_name;
942 bool used_opd = false;
943
944 if (!is_label && !elf_sym__is_a(&sym, map->type))
945 continue;
946
947 /* Reject ARM ELF "mapping symbols": these aren't unique and
948 * don't identify functions, so will confuse the profile
949 * output: */
950 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
951 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
952 && (elf_name[2] == '\0' || elf_name[2] == '.'))
953 continue;
954 }
955
956 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
957 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
958 u64 *opd = opddata->d_buf + offset;
959 sym.st_value = DSO__SWAP(dso, u64, *opd);
960 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
961 sym.st_value);
962 used_opd = true;
963 }
964 /*
965 * When loading symbols in a data mapping, ABS symbols (which
966 * has a value of SHN_ABS in its st_shndx) failed at
967 * elf_getscn(). And it marks the loading as a failure so
968 * already loaded symbols cannot be fixed up.
969 *
970 * I'm not sure what should be done. Just ignore them for now.
971 * - Namhyung Kim
972 */
973 if (sym.st_shndx == SHN_ABS)
974 continue;
975
976 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
977 if (!sec)
978 goto out_elf_end;
979
980 gelf_getshdr(sec, &shdr);
981
982 if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
983 continue;
984
985 section_name = elf_sec__name(&shdr, secstrs);
986
987 /* On ARM, symbols for thumb functions have 1 added to
988 * the symbol address as a flag - remove it */
989 if ((ehdr.e_machine == EM_ARM) &&
990 (map->type == MAP__FUNCTION) &&
991 (sym.st_value & 1))
992 --sym.st_value;
993
994 if (dso->kernel || kmodule) {
995 char dso_name[PATH_MAX];
996
997 /* Adjust symbol to map to file offset */
998 if (adjust_kernel_syms)
999 arch__adjust_sym_map_offset(&sym, &shdr, map);
1000
1001 if (strcmp(section_name,
1002 (curr_dso->short_name +
1003 dso->short_name_len)) == 0)
1004 goto new_symbol;
1005
1006 if (strcmp(section_name, ".text") == 0) {
1007 /*
1008 * The initial kernel mapping is based on
1009 * kallsyms and identity maps. Overwrite it to
1010 * map to the kernel dso.
1011 */
1012 if (remap_kernel && dso->kernel) {
1013 remap_kernel = false;
1014 map->start = shdr.sh_addr +
1015 ref_reloc(kmap);
1016 map->end = map->start + shdr.sh_size;
1017 map->pgoff = shdr.sh_offset;
1018 map->map_ip = map__map_ip;
1019 map->unmap_ip = map__unmap_ip;
1020 /* Ensure maps are correctly ordered */
1021 if (kmaps) {
1022 map__get(map);
1023 map_groups__remove(kmaps, map);
1024 map_groups__insert(kmaps, map);
1025 map__put(map);
1026 }
1027 }
1028
1029 /*
1030 * The initial module mapping is based on
1031 * /proc/modules mapped to offset zero.
1032 * Overwrite it to map to the module dso.
1033 */
1034 if (remap_kernel && kmodule) {
1035 remap_kernel = false;
1036 map->pgoff = shdr.sh_offset;
1037 }
1038
1039 curr_map = map;
1040 curr_dso = dso;
1041 goto new_symbol;
1042 }
1043
1044 if (!kmap)
1045 goto new_symbol;
1046
1047 snprintf(dso_name, sizeof(dso_name),
1048 "%s%s", dso->short_name, section_name);
1049
1050 curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
1051 if (curr_map == NULL) {
1052 u64 start = sym.st_value;
1053
1054 if (kmodule)
1055 start += map->start + shdr.sh_offset;
1056
1057 curr_dso = dso__new(dso_name);
1058 if (curr_dso == NULL)
1059 goto out_elf_end;
1060 curr_dso->kernel = dso->kernel;
1061 curr_dso->long_name = dso->long_name;
1062 curr_dso->long_name_len = dso->long_name_len;
1063 curr_map = map__new2(start, curr_dso,
1064 map->type);
1065 dso__put(curr_dso);
1066 if (curr_map == NULL) {
1067 goto out_elf_end;
1068 }
1069 if (adjust_kernel_syms) {
1070 curr_map->start = shdr.sh_addr +
1071 ref_reloc(kmap);
1072 curr_map->end = curr_map->start +
1073 shdr.sh_size;
1074 curr_map->pgoff = shdr.sh_offset;
1075 } else {
1076 curr_map->map_ip = identity__map_ip;
1077 curr_map->unmap_ip = identity__map_ip;
1078 }
1079 curr_dso->symtab_type = dso->symtab_type;
1080 map_groups__insert(kmaps, curr_map);
1081 /*
1082 * Add it before we drop the referece to curr_map,
1083 * i.e. while we still are sure to have a reference
1084 * to this DSO via curr_map->dso.
1085 */
1086 dsos__add(&map->groups->machine->dsos, curr_dso);
1087 /* kmaps already got it */
1088 map__put(curr_map);
1089 dso__set_loaded(curr_dso, map->type);
1090 } else
1091 curr_dso = curr_map->dso;
1092
1093 goto new_symbol;
1094 }
1095
1096 if ((used_opd && runtime_ss->adjust_symbols)
1097 || (!used_opd && syms_ss->adjust_symbols)) {
1098 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1099 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1100 (u64)sym.st_value, (u64)shdr.sh_addr,
1101 (u64)shdr.sh_offset);
1102 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1103 }
1104 new_symbol:
1105 demangled = demangle_sym(dso, kmodule, elf_name);
1106 if (demangled != NULL)
1107 elf_name = demangled;
1108
1109 f = symbol__new(sym.st_value, sym.st_size,
1110 GELF_ST_BIND(sym.st_info), elf_name);
1111 free(demangled);
1112 if (!f)
1113 goto out_elf_end;
1114
1115 arch__sym_update(f, &sym);
1116
1117 __symbols__insert(&curr_dso->symbols[curr_map->type], f, dso->kernel);
1118 nr++;
1119 }
1120
1121 /*
1122 * For misannotated, zeroed, ASM function sizes.
1123 */
1124 if (nr > 0) {
1125 symbols__fixup_end(&dso->symbols[map->type]);
1126 symbols__fixup_duplicate(&dso->symbols[map->type]);
1127 if (kmap) {
1128 /*
1129 * We need to fixup this here too because we create new
1130 * maps here, for things like vsyscall sections.
1131 */
1132 __map_groups__fixup_end(kmaps, map->type);
1133 }
1134 }
1135 err = nr;
1136 out_elf_end:
1137 return err;
1138 }
1139
1140 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1141 {
1142 GElf_Phdr phdr;
1143 size_t i, phdrnum;
1144 int err;
1145 u64 sz;
1146
1147 if (elf_getphdrnum(elf, &phdrnum))
1148 return -1;
1149
1150 for (i = 0; i < phdrnum; i++) {
1151 if (gelf_getphdr(elf, i, &phdr) == NULL)
1152 return -1;
1153 if (phdr.p_type != PT_LOAD)
1154 continue;
1155 if (exe) {
1156 if (!(phdr.p_flags & PF_X))
1157 continue;
1158 } else {
1159 if (!(phdr.p_flags & PF_R))
1160 continue;
1161 }
1162 sz = min(phdr.p_memsz, phdr.p_filesz);
1163 if (!sz)
1164 continue;
1165 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1166 if (err)
1167 return err;
1168 }
1169 return 0;
1170 }
1171
1172 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1173 bool *is_64_bit)
1174 {
1175 int err;
1176 Elf *elf;
1177
1178 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1179 if (elf == NULL)
1180 return -1;
1181
1182 if (is_64_bit)
1183 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1184
1185 err = elf_read_maps(elf, exe, mapfn, data);
1186
1187 elf_end(elf);
1188 return err;
1189 }
1190
1191 enum dso_type dso__type_fd(int fd)
1192 {
1193 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1194 GElf_Ehdr ehdr;
1195 Elf_Kind ek;
1196 Elf *elf;
1197
1198 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1199 if (elf == NULL)
1200 goto out;
1201
1202 ek = elf_kind(elf);
1203 if (ek != ELF_K_ELF)
1204 goto out_end;
1205
1206 if (gelf_getclass(elf) == ELFCLASS64) {
1207 dso_type = DSO__TYPE_64BIT;
1208 goto out_end;
1209 }
1210
1211 if (gelf_getehdr(elf, &ehdr) == NULL)
1212 goto out_end;
1213
1214 if (ehdr.e_machine == EM_X86_64)
1215 dso_type = DSO__TYPE_X32BIT;
1216 else
1217 dso_type = DSO__TYPE_32BIT;
1218 out_end:
1219 elf_end(elf);
1220 out:
1221 return dso_type;
1222 }
1223
1224 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1225 {
1226 ssize_t r;
1227 size_t n;
1228 int err = -1;
1229 char *buf = malloc(page_size);
1230
1231 if (buf == NULL)
1232 return -1;
1233
1234 if (lseek(to, to_offs, SEEK_SET) != to_offs)
1235 goto out;
1236
1237 if (lseek(from, from_offs, SEEK_SET) != from_offs)
1238 goto out;
1239
1240 while (len) {
1241 n = page_size;
1242 if (len < n)
1243 n = len;
1244 /* Use read because mmap won't work on proc files */
1245 r = read(from, buf, n);
1246 if (r < 0)
1247 goto out;
1248 if (!r)
1249 break;
1250 n = r;
1251 r = write(to, buf, n);
1252 if (r < 0)
1253 goto out;
1254 if ((size_t)r != n)
1255 goto out;
1256 len -= n;
1257 }
1258
1259 err = 0;
1260 out:
1261 free(buf);
1262 return err;
1263 }
1264
1265 struct kcore {
1266 int fd;
1267 int elfclass;
1268 Elf *elf;
1269 GElf_Ehdr ehdr;
1270 };
1271
1272 static int kcore__open(struct kcore *kcore, const char *filename)
1273 {
1274 GElf_Ehdr *ehdr;
1275
1276 kcore->fd = open(filename, O_RDONLY);
1277 if (kcore->fd == -1)
1278 return -1;
1279
1280 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1281 if (!kcore->elf)
1282 goto out_close;
1283
1284 kcore->elfclass = gelf_getclass(kcore->elf);
1285 if (kcore->elfclass == ELFCLASSNONE)
1286 goto out_end;
1287
1288 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1289 if (!ehdr)
1290 goto out_end;
1291
1292 return 0;
1293
1294 out_end:
1295 elf_end(kcore->elf);
1296 out_close:
1297 close(kcore->fd);
1298 return -1;
1299 }
1300
1301 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1302 bool temp)
1303 {
1304 kcore->elfclass = elfclass;
1305
1306 if (temp)
1307 kcore->fd = mkstemp(filename);
1308 else
1309 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1310 if (kcore->fd == -1)
1311 return -1;
1312
1313 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1314 if (!kcore->elf)
1315 goto out_close;
1316
1317 if (!gelf_newehdr(kcore->elf, elfclass))
1318 goto out_end;
1319
1320 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1321
1322 return 0;
1323
1324 out_end:
1325 elf_end(kcore->elf);
1326 out_close:
1327 close(kcore->fd);
1328 unlink(filename);
1329 return -1;
1330 }
1331
1332 static void kcore__close(struct kcore *kcore)
1333 {
1334 elf_end(kcore->elf);
1335 close(kcore->fd);
1336 }
1337
1338 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1339 {
1340 GElf_Ehdr *ehdr = &to->ehdr;
1341 GElf_Ehdr *kehdr = &from->ehdr;
1342
1343 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1344 ehdr->e_type = kehdr->e_type;
1345 ehdr->e_machine = kehdr->e_machine;
1346 ehdr->e_version = kehdr->e_version;
1347 ehdr->e_entry = 0;
1348 ehdr->e_shoff = 0;
1349 ehdr->e_flags = kehdr->e_flags;
1350 ehdr->e_phnum = count;
1351 ehdr->e_shentsize = 0;
1352 ehdr->e_shnum = 0;
1353 ehdr->e_shstrndx = 0;
1354
1355 if (from->elfclass == ELFCLASS32) {
1356 ehdr->e_phoff = sizeof(Elf32_Ehdr);
1357 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
1358 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1359 } else {
1360 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1361 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1362 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1363 }
1364
1365 if (!gelf_update_ehdr(to->elf, ehdr))
1366 return -1;
1367
1368 if (!gelf_newphdr(to->elf, count))
1369 return -1;
1370
1371 return 0;
1372 }
1373
1374 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1375 u64 addr, u64 len)
1376 {
1377 GElf_Phdr phdr = {
1378 .p_type = PT_LOAD,
1379 .p_flags = PF_R | PF_W | PF_X,
1380 .p_offset = offset,
1381 .p_vaddr = addr,
1382 .p_paddr = 0,
1383 .p_filesz = len,
1384 .p_memsz = len,
1385 .p_align = page_size,
1386 };
1387
1388 if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1389 return -1;
1390
1391 return 0;
1392 }
1393
1394 static off_t kcore__write(struct kcore *kcore)
1395 {
1396 return elf_update(kcore->elf, ELF_C_WRITE);
1397 }
1398
1399 struct phdr_data {
1400 off_t offset;
1401 u64 addr;
1402 u64 len;
1403 };
1404
1405 struct kcore_copy_info {
1406 u64 stext;
1407 u64 etext;
1408 u64 first_symbol;
1409 u64 last_symbol;
1410 u64 first_module;
1411 u64 last_module_symbol;
1412 struct phdr_data kernel_map;
1413 struct phdr_data modules_map;
1414 };
1415
1416 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1417 u64 start)
1418 {
1419 struct kcore_copy_info *kci = arg;
1420
1421 if (!symbol_type__is_a(type, MAP__FUNCTION))
1422 return 0;
1423
1424 if (strchr(name, '[')) {
1425 if (start > kci->last_module_symbol)
1426 kci->last_module_symbol = start;
1427 return 0;
1428 }
1429
1430 if (!kci->first_symbol || start < kci->first_symbol)
1431 kci->first_symbol = start;
1432
1433 if (!kci->last_symbol || start > kci->last_symbol)
1434 kci->last_symbol = start;
1435
1436 if (!strcmp(name, "_stext")) {
1437 kci->stext = start;
1438 return 0;
1439 }
1440
1441 if (!strcmp(name, "_etext")) {
1442 kci->etext = start;
1443 return 0;
1444 }
1445
1446 return 0;
1447 }
1448
1449 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1450 const char *dir)
1451 {
1452 char kallsyms_filename[PATH_MAX];
1453
1454 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1455
1456 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1457 return -1;
1458
1459 if (kallsyms__parse(kallsyms_filename, kci,
1460 kcore_copy__process_kallsyms) < 0)
1461 return -1;
1462
1463 return 0;
1464 }
1465
1466 static int kcore_copy__process_modules(void *arg,
1467 const char *name __maybe_unused,
1468 u64 start, u64 size __maybe_unused)
1469 {
1470 struct kcore_copy_info *kci = arg;
1471
1472 if (!kci->first_module || start < kci->first_module)
1473 kci->first_module = start;
1474
1475 return 0;
1476 }
1477
1478 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1479 const char *dir)
1480 {
1481 char modules_filename[PATH_MAX];
1482
1483 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1484
1485 if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1486 return -1;
1487
1488 if (modules__parse(modules_filename, kci,
1489 kcore_copy__process_modules) < 0)
1490 return -1;
1491
1492 return 0;
1493 }
1494
1495 static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
1496 u64 s, u64 e)
1497 {
1498 if (p->addr || s < start || s >= end)
1499 return;
1500
1501 p->addr = s;
1502 p->offset = (s - start) + pgoff;
1503 p->len = e < end ? e - s : end - s;
1504 }
1505
1506 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1507 {
1508 struct kcore_copy_info *kci = data;
1509 u64 end = start + len;
1510
1511 kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
1512 kci->etext);
1513
1514 kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
1515 kci->last_module_symbol);
1516
1517 return 0;
1518 }
1519
1520 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1521 {
1522 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1523 return -1;
1524
1525 return 0;
1526 }
1527
1528 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1529 Elf *elf)
1530 {
1531 if (kcore_copy__parse_kallsyms(kci, dir))
1532 return -1;
1533
1534 if (kcore_copy__parse_modules(kci, dir))
1535 return -1;
1536
1537 if (kci->stext)
1538 kci->stext = round_down(kci->stext, page_size);
1539 else
1540 kci->stext = round_down(kci->first_symbol, page_size);
1541
1542 if (kci->etext) {
1543 kci->etext = round_up(kci->etext, page_size);
1544 } else if (kci->last_symbol) {
1545 kci->etext = round_up(kci->last_symbol, page_size);
1546 kci->etext += page_size;
1547 }
1548
1549 kci->first_module = round_down(kci->first_module, page_size);
1550
1551 if (kci->last_module_symbol) {
1552 kci->last_module_symbol = round_up(kci->last_module_symbol,
1553 page_size);
1554 kci->last_module_symbol += page_size;
1555 }
1556
1557 if (!kci->stext || !kci->etext)
1558 return -1;
1559
1560 if (kci->first_module && !kci->last_module_symbol)
1561 return -1;
1562
1563 return kcore_copy__read_maps(kci, elf);
1564 }
1565
1566 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1567 const char *name)
1568 {
1569 char from_filename[PATH_MAX];
1570 char to_filename[PATH_MAX];
1571
1572 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1573 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1574
1575 return copyfile_mode(from_filename, to_filename, 0400);
1576 }
1577
1578 static int kcore_copy__unlink(const char *dir, const char *name)
1579 {
1580 char filename[PATH_MAX];
1581
1582 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1583
1584 return unlink(filename);
1585 }
1586
1587 static int kcore_copy__compare_fds(int from, int to)
1588 {
1589 char *buf_from;
1590 char *buf_to;
1591 ssize_t ret;
1592 size_t len;
1593 int err = -1;
1594
1595 buf_from = malloc(page_size);
1596 buf_to = malloc(page_size);
1597 if (!buf_from || !buf_to)
1598 goto out;
1599
1600 while (1) {
1601 /* Use read because mmap won't work on proc files */
1602 ret = read(from, buf_from, page_size);
1603 if (ret < 0)
1604 goto out;
1605
1606 if (!ret)
1607 break;
1608
1609 len = ret;
1610
1611 if (readn(to, buf_to, len) != (int)len)
1612 goto out;
1613
1614 if (memcmp(buf_from, buf_to, len))
1615 goto out;
1616 }
1617
1618 err = 0;
1619 out:
1620 free(buf_to);
1621 free(buf_from);
1622 return err;
1623 }
1624
1625 static int kcore_copy__compare_files(const char *from_filename,
1626 const char *to_filename)
1627 {
1628 int from, to, err = -1;
1629
1630 from = open(from_filename, O_RDONLY);
1631 if (from < 0)
1632 return -1;
1633
1634 to = open(to_filename, O_RDONLY);
1635 if (to < 0)
1636 goto out_close_from;
1637
1638 err = kcore_copy__compare_fds(from, to);
1639
1640 close(to);
1641 out_close_from:
1642 close(from);
1643 return err;
1644 }
1645
1646 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1647 const char *name)
1648 {
1649 char from_filename[PATH_MAX];
1650 char to_filename[PATH_MAX];
1651
1652 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1653 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1654
1655 return kcore_copy__compare_files(from_filename, to_filename);
1656 }
1657
1658 /**
1659 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1660 * @from_dir: from directory
1661 * @to_dir: to directory
1662 *
1663 * This function copies kallsyms, modules and kcore files from one directory to
1664 * another. kallsyms and modules are copied entirely. Only code segments are
1665 * copied from kcore. It is assumed that two segments suffice: one for the
1666 * kernel proper and one for all the modules. The code segments are determined
1667 * from kallsyms and modules files. The kernel map starts at _stext or the
1668 * lowest function symbol, and ends at _etext or the highest function symbol.
1669 * The module map starts at the lowest module address and ends at the highest
1670 * module symbol. Start addresses are rounded down to the nearest page. End
1671 * addresses are rounded up to the nearest page. An extra page is added to the
1672 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1673 * symbol too. Because it contains only code sections, the resulting kcore is
1674 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
1675 * is not the same for the kernel map and the modules map. That happens because
1676 * the data is copied adjacently whereas the original kcore has gaps. Finally,
1677 * kallsyms and modules files are compared with their copies to check that
1678 * modules have not been loaded or unloaded while the copies were taking place.
1679 *
1680 * Return: %0 on success, %-1 on failure.
1681 */
1682 int kcore_copy(const char *from_dir, const char *to_dir)
1683 {
1684 struct kcore kcore;
1685 struct kcore extract;
1686 size_t count = 2;
1687 int idx = 0, err = -1;
1688 off_t offset = page_size, sz, modules_offset = 0;
1689 struct kcore_copy_info kci = { .stext = 0, };
1690 char kcore_filename[PATH_MAX];
1691 char extract_filename[PATH_MAX];
1692
1693 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1694 return -1;
1695
1696 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1697 goto out_unlink_kallsyms;
1698
1699 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1700 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1701
1702 if (kcore__open(&kcore, kcore_filename))
1703 goto out_unlink_modules;
1704
1705 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1706 goto out_kcore_close;
1707
1708 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1709 goto out_kcore_close;
1710
1711 if (!kci.modules_map.addr)
1712 count -= 1;
1713
1714 if (kcore__copy_hdr(&kcore, &extract, count))
1715 goto out_extract_close;
1716
1717 if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
1718 kci.kernel_map.len))
1719 goto out_extract_close;
1720
1721 if (kci.modules_map.addr) {
1722 modules_offset = offset + kci.kernel_map.len;
1723 if (kcore__add_phdr(&extract, idx, modules_offset,
1724 kci.modules_map.addr, kci.modules_map.len))
1725 goto out_extract_close;
1726 }
1727
1728 sz = kcore__write(&extract);
1729 if (sz < 0 || sz > offset)
1730 goto out_extract_close;
1731
1732 if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
1733 kci.kernel_map.len))
1734 goto out_extract_close;
1735
1736 if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
1737 extract.fd, modules_offset,
1738 kci.modules_map.len))
1739 goto out_extract_close;
1740
1741 if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1742 goto out_extract_close;
1743
1744 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1745 goto out_extract_close;
1746
1747 err = 0;
1748
1749 out_extract_close:
1750 kcore__close(&extract);
1751 if (err)
1752 unlink(extract_filename);
1753 out_kcore_close:
1754 kcore__close(&kcore);
1755 out_unlink_modules:
1756 if (err)
1757 kcore_copy__unlink(to_dir, "modules");
1758 out_unlink_kallsyms:
1759 if (err)
1760 kcore_copy__unlink(to_dir, "kallsyms");
1761
1762 return err;
1763 }
1764
1765 int kcore_extract__create(struct kcore_extract *kce)
1766 {
1767 struct kcore kcore;
1768 struct kcore extract;
1769 size_t count = 1;
1770 int idx = 0, err = -1;
1771 off_t offset = page_size, sz;
1772
1773 if (kcore__open(&kcore, kce->kcore_filename))
1774 return -1;
1775
1776 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1777 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1778 goto out_kcore_close;
1779
1780 if (kcore__copy_hdr(&kcore, &extract, count))
1781 goto out_extract_close;
1782
1783 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1784 goto out_extract_close;
1785
1786 sz = kcore__write(&extract);
1787 if (sz < 0 || sz > offset)
1788 goto out_extract_close;
1789
1790 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1791 goto out_extract_close;
1792
1793 err = 0;
1794
1795 out_extract_close:
1796 kcore__close(&extract);
1797 if (err)
1798 unlink(kce->extract_filename);
1799 out_kcore_close:
1800 kcore__close(&kcore);
1801
1802 return err;
1803 }
1804
1805 void kcore_extract__delete(struct kcore_extract *kce)
1806 {
1807 unlink(kce->extract_filename);
1808 }
1809
1810 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1811 /**
1812 * populate_sdt_note : Parse raw data and identify SDT note
1813 * @elf: elf of the opened file
1814 * @data: raw data of a section with description offset applied
1815 * @len: note description size
1816 * @type: type of the note
1817 * @sdt_notes: List to add the SDT note
1818 *
1819 * Responsible for parsing the @data in section .note.stapsdt in @elf and
1820 * if its an SDT note, it appends to @sdt_notes list.
1821 */
1822 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
1823 struct list_head *sdt_notes)
1824 {
1825 const char *provider, *name, *args;
1826 struct sdt_note *tmp = NULL;
1827 GElf_Ehdr ehdr;
1828 GElf_Addr base_off = 0;
1829 GElf_Shdr shdr;
1830 int ret = -EINVAL;
1831
1832 union {
1833 Elf64_Addr a64[NR_ADDR];
1834 Elf32_Addr a32[NR_ADDR];
1835 } buf;
1836
1837 Elf_Data dst = {
1838 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
1839 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
1840 .d_off = 0, .d_align = 0
1841 };
1842 Elf_Data src = {
1843 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
1844 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
1845 .d_align = 0
1846 };
1847
1848 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
1849 if (!tmp) {
1850 ret = -ENOMEM;
1851 goto out_err;
1852 }
1853
1854 INIT_LIST_HEAD(&tmp->note_list);
1855
1856 if (len < dst.d_size + 3)
1857 goto out_free_note;
1858
1859 /* Translation from file representation to memory representation */
1860 if (gelf_xlatetom(*elf, &dst, &src,
1861 elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
1862 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
1863 goto out_free_note;
1864 }
1865
1866 /* Populate the fields of sdt_note */
1867 provider = data + dst.d_size;
1868
1869 name = (const char *)memchr(provider, '\0', data + len - provider);
1870 if (name++ == NULL)
1871 goto out_free_note;
1872
1873 tmp->provider = strdup(provider);
1874 if (!tmp->provider) {
1875 ret = -ENOMEM;
1876 goto out_free_note;
1877 }
1878 tmp->name = strdup(name);
1879 if (!tmp->name) {
1880 ret = -ENOMEM;
1881 goto out_free_prov;
1882 }
1883
1884 args = memchr(name, '\0', data + len - name);
1885
1886 /*
1887 * There is no argument if:
1888 * - We reached the end of the note;
1889 * - There is not enough room to hold a potential string;
1890 * - The argument string is empty or just contains ':'.
1891 */
1892 if (args == NULL || data + len - args < 2 ||
1893 args[1] == ':' || args[1] == '\0')
1894 tmp->args = NULL;
1895 else {
1896 tmp->args = strdup(++args);
1897 if (!tmp->args) {
1898 ret = -ENOMEM;
1899 goto out_free_name;
1900 }
1901 }
1902
1903 if (gelf_getclass(*elf) == ELFCLASS32) {
1904 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
1905 tmp->bit32 = true;
1906 } else {
1907 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
1908 tmp->bit32 = false;
1909 }
1910
1911 if (!gelf_getehdr(*elf, &ehdr)) {
1912 pr_debug("%s : cannot get elf header.\n", __func__);
1913 ret = -EBADF;
1914 goto out_free_args;
1915 }
1916
1917 /* Adjust the prelink effect :
1918 * Find out the .stapsdt.base section.
1919 * This scn will help us to handle prelinking (if present).
1920 * Compare the retrieved file offset of the base section with the
1921 * base address in the description of the SDT note. If its different,
1922 * then accordingly, adjust the note location.
1923 */
1924 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
1925 base_off = shdr.sh_offset;
1926 if (base_off) {
1927 if (tmp->bit32)
1928 tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
1929 tmp->addr.a32[1];
1930 else
1931 tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
1932 tmp->addr.a64[1];
1933 }
1934 }
1935
1936 list_add_tail(&tmp->note_list, sdt_notes);
1937 return 0;
1938
1939 out_free_args:
1940 free(tmp->args);
1941 out_free_name:
1942 free(tmp->name);
1943 out_free_prov:
1944 free(tmp->provider);
1945 out_free_note:
1946 free(tmp);
1947 out_err:
1948 return ret;
1949 }
1950
1951 /**
1952 * construct_sdt_notes_list : constructs a list of SDT notes
1953 * @elf : elf to look into
1954 * @sdt_notes : empty list_head
1955 *
1956 * Scans the sections in 'elf' for the section
1957 * .note.stapsdt. It, then calls populate_sdt_note to find
1958 * out the SDT events and populates the 'sdt_notes'.
1959 */
1960 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
1961 {
1962 GElf_Ehdr ehdr;
1963 Elf_Scn *scn = NULL;
1964 Elf_Data *data;
1965 GElf_Shdr shdr;
1966 size_t shstrndx, next;
1967 GElf_Nhdr nhdr;
1968 size_t name_off, desc_off, offset;
1969 int ret = 0;
1970
1971 if (gelf_getehdr(elf, &ehdr) == NULL) {
1972 ret = -EBADF;
1973 goto out_ret;
1974 }
1975 if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
1976 ret = -EBADF;
1977 goto out_ret;
1978 }
1979
1980 /* Look for the required section */
1981 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
1982 if (!scn) {
1983 ret = -ENOENT;
1984 goto out_ret;
1985 }
1986
1987 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
1988 ret = -ENOENT;
1989 goto out_ret;
1990 }
1991
1992 data = elf_getdata(scn, NULL);
1993
1994 /* Get the SDT notes */
1995 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
1996 &desc_off)) > 0; offset = next) {
1997 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
1998 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
1999 sizeof(SDT_NOTE_NAME))) {
2000 /* Check the type of the note */
2001 if (nhdr.n_type != SDT_NOTE_TYPE)
2002 goto out_ret;
2003
2004 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2005 nhdr.n_descsz, sdt_notes);
2006 if (ret < 0)
2007 goto out_ret;
2008 }
2009 }
2010 if (list_empty(sdt_notes))
2011 ret = -ENOENT;
2012
2013 out_ret:
2014 return ret;
2015 }
2016
2017 /**
2018 * get_sdt_note_list : Wrapper to construct a list of sdt notes
2019 * @head : empty list_head
2020 * @target : file to find SDT notes from
2021 *
2022 * This opens the file, initializes
2023 * the ELF and then calls construct_sdt_notes_list.
2024 */
2025 int get_sdt_note_list(struct list_head *head, const char *target)
2026 {
2027 Elf *elf;
2028 int fd, ret;
2029
2030 fd = open(target, O_RDONLY);
2031 if (fd < 0)
2032 return -EBADF;
2033
2034 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2035 if (!elf) {
2036 ret = -EBADF;
2037 goto out_close;
2038 }
2039 ret = construct_sdt_notes_list(elf, head);
2040 elf_end(elf);
2041 out_close:
2042 close(fd);
2043 return ret;
2044 }
2045
2046 /**
2047 * cleanup_sdt_note_list : free the sdt notes' list
2048 * @sdt_notes: sdt notes' list
2049 *
2050 * Free up the SDT notes in @sdt_notes.
2051 * Returns the number of SDT notes free'd.
2052 */
2053 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2054 {
2055 struct sdt_note *tmp, *pos;
2056 int nr_free = 0;
2057
2058 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2059 list_del(&pos->note_list);
2060 free(pos->name);
2061 free(pos->provider);
2062 free(pos);
2063 nr_free++;
2064 }
2065 return nr_free;
2066 }
2067
2068 /**
2069 * sdt_notes__get_count: Counts the number of sdt events
2070 * @start: list_head to sdt_notes list
2071 *
2072 * Returns the number of SDT notes in a list
2073 */
2074 int sdt_notes__get_count(struct list_head *start)
2075 {
2076 struct sdt_note *sdt_ptr;
2077 int count = 0;
2078
2079 list_for_each_entry(sdt_ptr, start, note_list)
2080 count++;
2081 return count;
2082 }
2083 #endif
2084
2085 void symbol__elf_init(void)
2086 {
2087 elf_version(EV_CURRENT);
2088 }
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