1 // SPDX-License-Identifier: GPL-2.0
12 #include "map_groups.h"
15 #include "demangle-java.h"
16 #include "demangle-rust.h"
20 #include "util/copyfile.h"
21 #include <linux/ctype.h>
22 #include <linux/kernel.h>
23 #include <linux/zalloc.h>
24 #include <symbol/kallsyms.h>
25 #include <internal/lib.h>
28 #define EM_AARCH64 183 /* ARM 64 bit */
31 #ifndef ELF32_ST_VISIBILITY
32 #define ELF32_ST_VISIBILITY(o) ((o) & 0x03)
35 /* For ELF64 the definitions are the same. */
36 #ifndef ELF64_ST_VISIBILITY
37 #define ELF64_ST_VISIBILITY(o) ELF32_ST_VISIBILITY (o)
40 /* How to extract information held in the st_other field. */
41 #ifndef GELF_ST_VISIBILITY
42 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
45 typedef Elf64_Nhdr GElf_Nhdr;
48 #define DMGL_NO_OPTS 0 /* For readability... */
49 #define DMGL_PARAMS (1 << 0) /* Include function args */
50 #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */
53 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
54 extern char *cplus_demangle(const char *, int);
56 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
58 return cplus_demangle(c, i);
62 static inline char *bfd_demangle(void __maybe_unused *v,
63 const char __maybe_unused *c,
69 #define PACKAGE 'perf'
74 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
75 static int elf_getphdrnum(Elf *elf, size_t *dst)
80 ehdr = gelf_getehdr(elf, &gehdr);
90 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
91 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
93 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
98 #ifndef NT_GNU_BUILD_ID
99 #define NT_GNU_BUILD_ID 3
103 * elf_symtab__for_each_symbol - iterate thru all the symbols
105 * @syms: struct elf_symtab instance to iterate
107 * @sym: GElf_Sym iterator
109 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
110 for (idx = 0, gelf_getsym(syms, idx, &sym);\
112 idx++, gelf_getsym(syms, idx, &sym))
114 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
116 return GELF_ST_TYPE(sym->st_info);
119 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
121 return GELF_ST_VISIBILITY(sym->st_other);
124 #ifndef STT_GNU_IFUNC
125 #define STT_GNU_IFUNC 10
128 static inline int elf_sym__is_function(const GElf_Sym *sym)
130 return (elf_sym__type(sym) == STT_FUNC ||
131 elf_sym__type(sym) == STT_GNU_IFUNC) &&
133 sym->st_shndx != SHN_UNDEF;
136 static inline bool elf_sym__is_object(const GElf_Sym *sym)
138 return elf_sym__type(sym) == STT_OBJECT &&
140 sym->st_shndx != SHN_UNDEF;
143 static inline int elf_sym__is_label(const GElf_Sym *sym)
145 return elf_sym__type(sym) == STT_NOTYPE &&
147 sym->st_shndx != SHN_UNDEF &&
148 sym->st_shndx != SHN_ABS &&
149 elf_sym__visibility(sym) != STV_HIDDEN &&
150 elf_sym__visibility(sym) != STV_INTERNAL;
153 static bool elf_sym__filter(GElf_Sym *sym)
155 return elf_sym__is_function(sym) || elf_sym__is_object(sym);
158 static inline const char *elf_sym__name(const GElf_Sym *sym,
159 const Elf_Data *symstrs)
161 return symstrs->d_buf + sym->st_name;
164 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
165 const Elf_Data *secstrs)
167 return secstrs->d_buf + shdr->sh_name;
170 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
171 const Elf_Data *secstrs)
173 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
176 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
177 const Elf_Data *secstrs)
179 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
182 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
184 return elf_sec__is_text(shdr, secstrs) ||
185 elf_sec__is_data(shdr, secstrs);
188 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
194 while ((sec = elf_nextscn(elf, sec)) != NULL) {
195 gelf_getshdr(sec, &shdr);
197 if ((addr >= shdr.sh_addr) &&
198 (addr < (shdr.sh_addr + shdr.sh_size)))
207 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
208 GElf_Shdr *shp, const char *name, size_t *idx)
213 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
214 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
217 while ((sec = elf_nextscn(elf, sec)) != NULL) {
220 gelf_getshdr(sec, shp);
221 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
222 if (str && !strcmp(name, str)) {
233 static bool want_demangle(bool is_kernel_sym)
235 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
238 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
240 int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
241 char *demangled = NULL;
244 * We need to figure out if the object was created from C++ sources
245 * DWARF DW_compile_unit has this, but we don't always have access
248 if (!want_demangle(dso->kernel || kmodule))
251 demangled = bfd_demangle(NULL, elf_name, demangle_flags);
252 if (demangled == NULL)
253 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
254 else if (rust_is_mangled(demangled))
256 * Input to Rust demangling is the BFD-demangled
257 * name which it Rust-demangles in place.
259 rust_demangle_sym(demangled);
264 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
265 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
267 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
269 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
270 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
272 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
275 * We need to check if we have a .dynsym, so that we can handle the
276 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
277 * .dynsym or .symtab).
278 * And always look at the original dso, not at debuginfo packages, that
279 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
281 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
283 uint32_t nr_rel_entries, idx;
285 u64 plt_offset, plt_header_size, plt_entry_size;
288 GElf_Shdr shdr_rel_plt, shdr_dynsym;
289 Elf_Data *reldata, *syms, *symstrs;
290 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
293 char sympltname[1024];
295 int nr = 0, symidx, err = 0;
303 scn_dynsym = ss->dynsym;
304 shdr_dynsym = ss->dynshdr;
305 dynsym_idx = ss->dynsym_idx;
307 if (scn_dynsym == NULL)
310 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
312 if (scn_plt_rel == NULL) {
313 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
315 if (scn_plt_rel == NULL)
321 if (shdr_rel_plt.sh_link != dynsym_idx)
324 if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
328 * Fetch the relocation section to find the idxes to the GOT
329 * and the symbols in the .dynsym they refer to.
331 reldata = elf_getdata(scn_plt_rel, NULL);
335 syms = elf_getdata(scn_dynsym, NULL);
339 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
340 if (scn_symstrs == NULL)
343 symstrs = elf_getdata(scn_symstrs, NULL);
347 if (symstrs->d_size == 0)
350 nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
351 plt_offset = shdr_plt.sh_offset;
352 switch (ehdr.e_machine) {
354 plt_header_size = 20;
359 plt_header_size = 32;
364 plt_header_size = 48;
369 plt_header_size = 128;
373 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
374 plt_header_size = shdr_plt.sh_entsize;
375 plt_entry_size = shdr_plt.sh_entsize;
378 plt_offset += plt_header_size;
380 if (shdr_rel_plt.sh_type == SHT_RELA) {
381 GElf_Rela pos_mem, *pos;
383 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
385 const char *elf_name = NULL;
386 char *demangled = NULL;
387 symidx = GELF_R_SYM(pos->r_info);
388 gelf_getsym(syms, symidx, &sym);
390 elf_name = elf_sym__name(&sym, symstrs);
391 demangled = demangle_sym(dso, 0, elf_name);
392 if (demangled != NULL)
393 elf_name = demangled;
394 snprintf(sympltname, sizeof(sympltname),
398 f = symbol__new(plt_offset, plt_entry_size,
399 STB_GLOBAL, STT_FUNC, sympltname);
403 plt_offset += plt_entry_size;
404 symbols__insert(&dso->symbols, f);
407 } else if (shdr_rel_plt.sh_type == SHT_REL) {
408 GElf_Rel pos_mem, *pos;
409 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
411 const char *elf_name = NULL;
412 char *demangled = NULL;
413 symidx = GELF_R_SYM(pos->r_info);
414 gelf_getsym(syms, symidx, &sym);
416 elf_name = elf_sym__name(&sym, symstrs);
417 demangled = demangle_sym(dso, 0, elf_name);
418 if (demangled != NULL)
419 elf_name = demangled;
420 snprintf(sympltname, sizeof(sympltname),
424 f = symbol__new(plt_offset, plt_entry_size,
425 STB_GLOBAL, STT_FUNC, sympltname);
429 plt_offset += plt_entry_size;
430 symbols__insert(&dso->symbols, f);
439 pr_debug("%s: problems reading %s PLT info.\n",
440 __func__, dso->long_name);
444 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
446 return demangle_sym(dso, kmodule, elf_name);
450 * Align offset to 4 bytes as needed for note name and descriptor data.
452 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
454 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
464 if (size < BUILD_ID_SIZE)
471 if (gelf_getehdr(elf, &ehdr) == NULL) {
472 pr_err("%s: cannot get elf header.\n", __func__);
477 * Check following sections for notes:
478 * '.note.gnu.build-id'
480 * '.note' (VDSO specific)
483 sec = elf_section_by_name(elf, &ehdr, &shdr,
484 ".note.gnu.build-id", NULL);
488 sec = elf_section_by_name(elf, &ehdr, &shdr,
493 sec = elf_section_by_name(elf, &ehdr, &shdr,
502 data = elf_getdata(sec, NULL);
507 while (ptr < (data->d_buf + data->d_size)) {
508 GElf_Nhdr *nhdr = ptr;
509 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
510 descsz = NOTE_ALIGN(nhdr->n_descsz);
513 ptr += sizeof(*nhdr);
516 if (nhdr->n_type == NT_GNU_BUILD_ID &&
517 nhdr->n_namesz == sizeof("GNU")) {
518 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
519 size_t sz = min(size, descsz);
521 memset(bf + sz, 0, size - sz);
533 int filename__read_build_id(const char *filename, void *bf, size_t size)
538 if (size < BUILD_ID_SIZE)
541 fd = open(filename, O_RDONLY);
545 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
547 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
551 err = elf_read_build_id(elf, bf, size);
560 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
564 if (size < BUILD_ID_SIZE)
567 fd = open(filename, O_RDONLY);
574 size_t namesz, descsz;
576 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
579 namesz = NOTE_ALIGN(nhdr.n_namesz);
580 descsz = NOTE_ALIGN(nhdr.n_descsz);
581 if (nhdr.n_type == NT_GNU_BUILD_ID &&
582 nhdr.n_namesz == sizeof("GNU")) {
583 if (read(fd, bf, namesz) != (ssize_t)namesz)
585 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
586 size_t sz = min(descsz, size);
587 if (read(fd, build_id, sz) == (ssize_t)sz) {
588 memset(build_id + sz, 0, size - sz);
592 } else if (read(fd, bf, descsz) != (ssize_t)descsz)
595 int n = namesz + descsz;
597 if (n > (int)sizeof(bf)) {
599 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
600 __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
602 if (read(fd, bf, n) != n)
611 int filename__read_debuglink(const char *filename, char *debuglink,
622 fd = open(filename, O_RDONLY);
626 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
628 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
636 if (gelf_getehdr(elf, &ehdr) == NULL) {
637 pr_err("%s: cannot get elf header.\n", __func__);
641 sec = elf_section_by_name(elf, &ehdr, &shdr,
642 ".gnu_debuglink", NULL);
646 data = elf_getdata(sec, NULL);
650 /* the start of this section is a zero-terminated string */
651 strncpy(debuglink, data->d_buf, size);
663 static int dso__swap_init(struct dso *dso, unsigned char eidata)
665 static unsigned int const endian = 1;
667 dso->needs_swap = DSO_SWAP__NO;
671 /* We are big endian, DSO is little endian. */
672 if (*(unsigned char const *)&endian != 1)
673 dso->needs_swap = DSO_SWAP__YES;
677 /* We are little endian, DSO is big endian. */
678 if (*(unsigned char const *)&endian != 0)
679 dso->needs_swap = DSO_SWAP__YES;
683 pr_err("unrecognized DSO data encoding %d\n", eidata);
690 bool symsrc__possibly_runtime(struct symsrc *ss)
692 return ss->dynsym || ss->opdsec;
695 bool symsrc__has_symtab(struct symsrc *ss)
697 return ss->symtab != NULL;
700 void symsrc__destroy(struct symsrc *ss)
707 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
709 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
712 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
713 enum dso_binary_type type)
719 if (dso__needs_decompress(dso)) {
720 fd = dso__decompress_kmodule_fd(dso, name);
724 type = dso->symtab_type;
726 fd = open(name, O_RDONLY);
728 dso->load_errno = errno;
733 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
735 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
736 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
740 if (gelf_getehdr(elf, &ehdr) == NULL) {
741 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
742 pr_debug("%s: cannot get elf header.\n", __func__);
746 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
747 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
751 /* Always reject images with a mismatched build-id: */
752 if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
753 u8 build_id[BUILD_ID_SIZE];
755 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
756 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
760 if (!dso__build_id_equal(dso, build_id)) {
761 pr_debug("%s: build id mismatch for %s.\n", __func__, name);
762 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
767 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
769 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
771 if (ss->symshdr.sh_type != SHT_SYMTAB)
775 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
777 if (ss->dynshdr.sh_type != SHT_DYNSYM)
781 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
783 if (ss->opdshdr.sh_type != SHT_PROGBITS)
786 if (dso->kernel == DSO_TYPE_USER)
787 ss->adjust_symbols = true;
789 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
791 ss->name = strdup(name);
793 dso->load_errno = errno;
812 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
813 * @kmap: kernel maps and relocation reference symbol
815 * This function returns %true if we are dealing with the kernel maps and the
816 * relocation reference symbol has not yet been found. Otherwise %false is
819 static bool ref_reloc_sym_not_found(struct kmap *kmap)
821 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
822 !kmap->ref_reloc_sym->unrelocated_addr;
826 * ref_reloc - kernel relocation offset.
827 * @kmap: kernel maps and relocation reference symbol
829 * This function returns the offset of kernel addresses as determined by using
830 * the relocation reference symbol i.e. if the kernel has not been relocated
831 * then the return value is zero.
833 static u64 ref_reloc(struct kmap *kmap)
835 if (kmap && kmap->ref_reloc_sym &&
836 kmap->ref_reloc_sym->unrelocated_addr)
837 return kmap->ref_reloc_sym->addr -
838 kmap->ref_reloc_sym->unrelocated_addr;
842 void __weak arch__sym_update(struct symbol *s __maybe_unused,
843 GElf_Sym *sym __maybe_unused) { }
845 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
846 GElf_Sym *sym, GElf_Shdr *shdr,
847 struct map_groups *kmaps, struct kmap *kmap,
848 struct dso **curr_dsop, struct map **curr_mapp,
849 const char *section_name,
850 bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
852 struct dso *curr_dso = *curr_dsop;
853 struct map *curr_map;
854 char dso_name[PATH_MAX];
856 /* Adjust symbol to map to file offset */
857 if (adjust_kernel_syms)
858 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
860 if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
863 if (strcmp(section_name, ".text") == 0) {
865 * The initial kernel mapping is based on
866 * kallsyms and identity maps. Overwrite it to
867 * map to the kernel dso.
869 if (*remap_kernel && dso->kernel) {
870 *remap_kernel = false;
871 map->start = shdr->sh_addr + ref_reloc(kmap);
872 map->end = map->start + shdr->sh_size;
873 map->pgoff = shdr->sh_offset;
874 map->map_ip = map__map_ip;
875 map->unmap_ip = map__unmap_ip;
876 /* Ensure maps are correctly ordered */
879 map_groups__remove(kmaps, map);
880 map_groups__insert(kmaps, map);
886 * The initial module mapping is based on
887 * /proc/modules mapped to offset zero.
888 * Overwrite it to map to the module dso.
890 if (*remap_kernel && kmodule) {
891 *remap_kernel = false;
892 map->pgoff = shdr->sh_offset;
903 snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
905 curr_map = map_groups__find_by_name(kmaps, dso_name);
906 if (curr_map == NULL) {
907 u64 start = sym->st_value;
910 start += map->start + shdr->sh_offset;
912 curr_dso = dso__new(dso_name);
913 if (curr_dso == NULL)
915 curr_dso->kernel = dso->kernel;
916 curr_dso->long_name = dso->long_name;
917 curr_dso->long_name_len = dso->long_name_len;
918 curr_map = map__new2(start, curr_dso);
920 if (curr_map == NULL)
923 if (adjust_kernel_syms) {
924 curr_map->start = shdr->sh_addr + ref_reloc(kmap);
925 curr_map->end = curr_map->start + shdr->sh_size;
926 curr_map->pgoff = shdr->sh_offset;
928 curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
930 curr_dso->symtab_type = dso->symtab_type;
931 map_groups__insert(kmaps, curr_map);
933 * Add it before we drop the referece to curr_map, i.e. while
934 * we still are sure to have a reference to this DSO via
937 dsos__add(&map->groups->machine->dsos, curr_dso);
938 /* kmaps already got it */
940 dso__set_loaded(curr_dso);
941 *curr_mapp = curr_map;
942 *curr_dsop = curr_dso;
944 *curr_dsop = curr_map->dso;
949 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
950 struct symsrc *runtime_ss, int kmodule)
952 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
953 struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
954 struct map *curr_map = map;
955 struct dso *curr_dso = dso;
956 Elf_Data *symstrs, *secstrs;
963 Elf_Data *syms, *opddata = NULL;
965 Elf_Scn *sec, *sec_strndx;
968 bool remap_kernel = false, adjust_kernel_syms = false;
973 dso->symtab_type = syms_ss->type;
974 dso->is_64_bit = syms_ss->is_64_bit;
975 dso->rel = syms_ss->ehdr.e_type == ET_REL;
978 * Modules may already have symbols from kallsyms, but those symbols
979 * have the wrong values for the dso maps, so remove them.
981 if (kmodule && syms_ss->symtab)
982 symbols__delete(&dso->symbols);
984 if (!syms_ss->symtab) {
986 * If the vmlinux is stripped, fail so we will fall back
987 * to using kallsyms. The vmlinux runtime symbols aren't
993 syms_ss->symtab = syms_ss->dynsym;
994 syms_ss->symshdr = syms_ss->dynshdr;
998 ehdr = syms_ss->ehdr;
999 sec = syms_ss->symtab;
1000 shdr = syms_ss->symshdr;
1002 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1004 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1006 if (runtime_ss->opdsec)
1007 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1009 syms = elf_getdata(sec, NULL);
1013 sec = elf_getscn(elf, shdr.sh_link);
1017 symstrs = elf_getdata(sec, NULL);
1018 if (symstrs == NULL)
1021 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1022 if (sec_strndx == NULL)
1025 secstrs = elf_getdata(sec_strndx, NULL);
1026 if (secstrs == NULL)
1029 nr_syms = shdr.sh_size / shdr.sh_entsize;
1031 memset(&sym, 0, sizeof(sym));
1034 * The kernel relocation symbol is needed in advance in order to adjust
1035 * kernel maps correctly.
1037 if (ref_reloc_sym_not_found(kmap)) {
1038 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1039 const char *elf_name = elf_sym__name(&sym, symstrs);
1041 if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1043 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1044 map->reloc = kmap->ref_reloc_sym->addr -
1045 kmap->ref_reloc_sym->unrelocated_addr;
1051 * Handle any relocation of vdso necessary because older kernels
1052 * attempted to prelink vdso to its virtual address.
1054 if (dso__is_vdso(dso))
1055 map->reloc = map->start - dso->text_offset;
1057 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1059 * Initial kernel and module mappings do not map to the dso.
1062 if (dso->kernel || kmodule) {
1063 remap_kernel = true;
1064 adjust_kernel_syms = dso->adjust_symbols;
1066 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1068 const char *elf_name = elf_sym__name(&sym, symstrs);
1069 char *demangled = NULL;
1070 int is_label = elf_sym__is_label(&sym);
1071 const char *section_name;
1072 bool used_opd = false;
1074 if (!is_label && !elf_sym__filter(&sym))
1077 /* Reject ARM ELF "mapping symbols": these aren't unique and
1078 * don't identify functions, so will confuse the profile
1080 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1081 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1082 && (elf_name[2] == '\0' || elf_name[2] == '.'))
1086 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1087 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1088 u64 *opd = opddata->d_buf + offset;
1089 sym.st_value = DSO__SWAP(dso, u64, *opd);
1090 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1095 * When loading symbols in a data mapping, ABS symbols (which
1096 * has a value of SHN_ABS in its st_shndx) failed at
1097 * elf_getscn(). And it marks the loading as a failure so
1098 * already loaded symbols cannot be fixed up.
1100 * I'm not sure what should be done. Just ignore them for now.
1103 if (sym.st_shndx == SHN_ABS)
1106 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1110 gelf_getshdr(sec, &shdr);
1112 if (is_label && !elf_sec__filter(&shdr, secstrs))
1115 section_name = elf_sec__name(&shdr, secstrs);
1117 /* On ARM, symbols for thumb functions have 1 added to
1118 * the symbol address as a flag - remove it */
1119 if ((ehdr.e_machine == EM_ARM) &&
1120 (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1124 if (dso->kernel || kmodule) {
1125 if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1126 section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1128 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1129 (!used_opd && syms_ss->adjust_symbols)) {
1130 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1131 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1132 (u64)sym.st_value, (u64)shdr.sh_addr,
1133 (u64)shdr.sh_offset);
1134 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1137 demangled = demangle_sym(dso, kmodule, elf_name);
1138 if (demangled != NULL)
1139 elf_name = demangled;
1141 f = symbol__new(sym.st_value, sym.st_size,
1142 GELF_ST_BIND(sym.st_info),
1143 GELF_ST_TYPE(sym.st_info), elf_name);
1148 arch__sym_update(f, &sym);
1150 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1155 * For misannotated, zeroed, ASM function sizes.
1158 symbols__fixup_end(&dso->symbols);
1159 symbols__fixup_duplicate(&dso->symbols);
1162 * We need to fixup this here too because we create new
1163 * maps here, for things like vsyscall sections.
1165 map_groups__fixup_end(kmaps);
1173 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1180 if (elf_getphdrnum(elf, &phdrnum))
1183 for (i = 0; i < phdrnum; i++) {
1184 if (gelf_getphdr(elf, i, &phdr) == NULL)
1186 if (phdr.p_type != PT_LOAD)
1189 if (!(phdr.p_flags & PF_X))
1192 if (!(phdr.p_flags & PF_R))
1195 sz = min(phdr.p_memsz, phdr.p_filesz);
1198 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1205 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1211 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1216 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1218 err = elf_read_maps(elf, exe, mapfn, data);
1224 enum dso_type dso__type_fd(int fd)
1226 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1231 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1236 if (ek != ELF_K_ELF)
1239 if (gelf_getclass(elf) == ELFCLASS64) {
1240 dso_type = DSO__TYPE_64BIT;
1244 if (gelf_getehdr(elf, &ehdr) == NULL)
1247 if (ehdr.e_machine == EM_X86_64)
1248 dso_type = DSO__TYPE_X32BIT;
1250 dso_type = DSO__TYPE_32BIT;
1257 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1262 char *buf = malloc(page_size);
1267 if (lseek(to, to_offs, SEEK_SET) != to_offs)
1270 if (lseek(from, from_offs, SEEK_SET) != from_offs)
1277 /* Use read because mmap won't work on proc files */
1278 r = read(from, buf, n);
1284 r = write(to, buf, n);
1305 static int kcore__open(struct kcore *kcore, const char *filename)
1309 kcore->fd = open(filename, O_RDONLY);
1310 if (kcore->fd == -1)
1313 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1317 kcore->elfclass = gelf_getclass(kcore->elf);
1318 if (kcore->elfclass == ELFCLASSNONE)
1321 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1328 elf_end(kcore->elf);
1334 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1337 kcore->elfclass = elfclass;
1340 kcore->fd = mkstemp(filename);
1342 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1343 if (kcore->fd == -1)
1346 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1350 if (!gelf_newehdr(kcore->elf, elfclass))
1353 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1358 elf_end(kcore->elf);
1365 static void kcore__close(struct kcore *kcore)
1367 elf_end(kcore->elf);
1371 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1373 GElf_Ehdr *ehdr = &to->ehdr;
1374 GElf_Ehdr *kehdr = &from->ehdr;
1376 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1377 ehdr->e_type = kehdr->e_type;
1378 ehdr->e_machine = kehdr->e_machine;
1379 ehdr->e_version = kehdr->e_version;
1382 ehdr->e_flags = kehdr->e_flags;
1383 ehdr->e_phnum = count;
1384 ehdr->e_shentsize = 0;
1386 ehdr->e_shstrndx = 0;
1388 if (from->elfclass == ELFCLASS32) {
1389 ehdr->e_phoff = sizeof(Elf32_Ehdr);
1390 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
1391 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1393 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1394 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1395 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1398 if (!gelf_update_ehdr(to->elf, ehdr))
1401 if (!gelf_newphdr(to->elf, count))
1407 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1412 .p_flags = PF_R | PF_W | PF_X,
1418 .p_align = page_size,
1421 if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1427 static off_t kcore__write(struct kcore *kcore)
1429 return elf_update(kcore->elf, ELF_C_WRITE);
1437 struct list_head node;
1438 struct phdr_data *remaps;
1443 struct list_head node;
1446 struct kcore_copy_info {
1452 u64 last_module_symbol;
1454 struct list_head phdrs;
1455 struct list_head syms;
1458 #define kcore_copy__for_each_phdr(k, p) \
1459 list_for_each_entry((p), &(k)->phdrs, node)
1461 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1463 struct phdr_data *p = zalloc(sizeof(*p));
1474 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1478 struct phdr_data *p = phdr_data__new(addr, len, offset);
1481 list_add_tail(&p->node, &kci->phdrs);
1486 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1488 struct phdr_data *p, *tmp;
1490 list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1491 list_del_init(&p->node);
1496 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1499 struct sym_data *s = zalloc(sizeof(*s));
1503 list_add_tail(&s->node, &kci->syms);
1509 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1511 struct sym_data *s, *tmp;
1513 list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1514 list_del_init(&s->node);
1519 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1522 struct kcore_copy_info *kci = arg;
1524 if (!kallsyms__is_function(type))
1527 if (strchr(name, '[')) {
1528 if (start > kci->last_module_symbol)
1529 kci->last_module_symbol = start;
1533 if (!kci->first_symbol || start < kci->first_symbol)
1534 kci->first_symbol = start;
1536 if (!kci->last_symbol || start > kci->last_symbol)
1537 kci->last_symbol = start;
1539 if (!strcmp(name, "_stext")) {
1544 if (!strcmp(name, "_etext")) {
1549 if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1555 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1558 char kallsyms_filename[PATH_MAX];
1560 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1562 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1565 if (kallsyms__parse(kallsyms_filename, kci,
1566 kcore_copy__process_kallsyms) < 0)
1572 static int kcore_copy__process_modules(void *arg,
1573 const char *name __maybe_unused,
1574 u64 start, u64 size __maybe_unused)
1576 struct kcore_copy_info *kci = arg;
1578 if (!kci->first_module || start < kci->first_module)
1579 kci->first_module = start;
1584 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1587 char modules_filename[PATH_MAX];
1589 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1591 if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1594 if (modules__parse(modules_filename, kci,
1595 kcore_copy__process_modules) < 0)
1601 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1602 u64 pgoff, u64 s, u64 e)
1606 if (s < start || s >= end)
1609 offset = (s - start) + pgoff;
1610 len = e < end ? e - s : end - s;
1612 return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1615 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1617 struct kcore_copy_info *kci = data;
1618 u64 end = start + len;
1619 struct sym_data *sdat;
1621 if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1624 if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1625 kci->last_module_symbol))
1628 list_for_each_entry(sdat, &kci->syms, node) {
1629 u64 s = round_down(sdat->addr, page_size);
1631 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1638 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1640 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1646 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1648 struct phdr_data *p, *k = NULL;
1654 /* Find phdr that corresponds to the kernel map (contains stext) */
1655 kcore_copy__for_each_phdr(kci, p) {
1656 u64 pend = p->addr + p->len - 1;
1658 if (p->addr <= kci->stext && pend >= kci->stext) {
1667 kend = k->offset + k->len;
1669 /* Find phdrs that remap the kernel */
1670 kcore_copy__for_each_phdr(kci, p) {
1671 u64 pend = p->offset + p->len;
1676 if (p->offset >= k->offset && pend <= kend)
1681 static void kcore_copy__layout(struct kcore_copy_info *kci)
1683 struct phdr_data *p;
1686 kcore_copy__find_remaps(kci);
1688 kcore_copy__for_each_phdr(kci, p) {
1696 kcore_copy__for_each_phdr(kci, p) {
1697 struct phdr_data *k = p->remaps;
1700 p->rel = p->offset - k->offset + k->rel;
1704 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1707 if (kcore_copy__parse_kallsyms(kci, dir))
1710 if (kcore_copy__parse_modules(kci, dir))
1714 kci->stext = round_down(kci->stext, page_size);
1716 kci->stext = round_down(kci->first_symbol, page_size);
1719 kci->etext = round_up(kci->etext, page_size);
1720 } else if (kci->last_symbol) {
1721 kci->etext = round_up(kci->last_symbol, page_size);
1722 kci->etext += page_size;
1725 kci->first_module = round_down(kci->first_module, page_size);
1727 if (kci->last_module_symbol) {
1728 kci->last_module_symbol = round_up(kci->last_module_symbol,
1730 kci->last_module_symbol += page_size;
1733 if (!kci->stext || !kci->etext)
1736 if (kci->first_module && !kci->last_module_symbol)
1739 if (kcore_copy__read_maps(kci, elf))
1742 kcore_copy__layout(kci);
1747 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1750 char from_filename[PATH_MAX];
1751 char to_filename[PATH_MAX];
1753 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1754 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1756 return copyfile_mode(from_filename, to_filename, 0400);
1759 static int kcore_copy__unlink(const char *dir, const char *name)
1761 char filename[PATH_MAX];
1763 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1765 return unlink(filename);
1768 static int kcore_copy__compare_fds(int from, int to)
1776 buf_from = malloc(page_size);
1777 buf_to = malloc(page_size);
1778 if (!buf_from || !buf_to)
1782 /* Use read because mmap won't work on proc files */
1783 ret = read(from, buf_from, page_size);
1792 if (readn(to, buf_to, len) != (int)len)
1795 if (memcmp(buf_from, buf_to, len))
1806 static int kcore_copy__compare_files(const char *from_filename,
1807 const char *to_filename)
1809 int from, to, err = -1;
1811 from = open(from_filename, O_RDONLY);
1815 to = open(to_filename, O_RDONLY);
1817 goto out_close_from;
1819 err = kcore_copy__compare_fds(from, to);
1827 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1830 char from_filename[PATH_MAX];
1831 char to_filename[PATH_MAX];
1833 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1834 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1836 return kcore_copy__compare_files(from_filename, to_filename);
1840 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1841 * @from_dir: from directory
1842 * @to_dir: to directory
1844 * This function copies kallsyms, modules and kcore files from one directory to
1845 * another. kallsyms and modules are copied entirely. Only code segments are
1846 * copied from kcore. It is assumed that two segments suffice: one for the
1847 * kernel proper and one for all the modules. The code segments are determined
1848 * from kallsyms and modules files. The kernel map starts at _stext or the
1849 * lowest function symbol, and ends at _etext or the highest function symbol.
1850 * The module map starts at the lowest module address and ends at the highest
1851 * module symbol. Start addresses are rounded down to the nearest page. End
1852 * addresses are rounded up to the nearest page. An extra page is added to the
1853 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1854 * symbol too. Because it contains only code sections, the resulting kcore is
1855 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
1856 * is not the same for the kernel map and the modules map. That happens because
1857 * the data is copied adjacently whereas the original kcore has gaps. Finally,
1858 * kallsyms and modules files are compared with their copies to check that
1859 * modules have not been loaded or unloaded while the copies were taking place.
1861 * Return: %0 on success, %-1 on failure.
1863 int kcore_copy(const char *from_dir, const char *to_dir)
1866 struct kcore extract;
1867 int idx = 0, err = -1;
1869 struct kcore_copy_info kci = { .stext = 0, };
1870 char kcore_filename[PATH_MAX];
1871 char extract_filename[PATH_MAX];
1872 struct phdr_data *p;
1874 INIT_LIST_HEAD(&kci.phdrs);
1875 INIT_LIST_HEAD(&kci.syms);
1877 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1880 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1881 goto out_unlink_kallsyms;
1883 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1884 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1886 if (kcore__open(&kcore, kcore_filename))
1887 goto out_unlink_modules;
1889 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1890 goto out_kcore_close;
1892 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1893 goto out_kcore_close;
1895 if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
1896 goto out_extract_close;
1898 offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
1899 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
1900 offset = round_up(offset, page_size);
1902 kcore_copy__for_each_phdr(&kci, p) {
1903 off_t offs = p->rel + offset;
1905 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
1906 goto out_extract_close;
1909 sz = kcore__write(&extract);
1910 if (sz < 0 || sz > offset)
1911 goto out_extract_close;
1913 kcore_copy__for_each_phdr(&kci, p) {
1914 off_t offs = p->rel + offset;
1918 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
1919 goto out_extract_close;
1922 if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1923 goto out_extract_close;
1925 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1926 goto out_extract_close;
1931 kcore__close(&extract);
1933 unlink(extract_filename);
1935 kcore__close(&kcore);
1938 kcore_copy__unlink(to_dir, "modules");
1939 out_unlink_kallsyms:
1941 kcore_copy__unlink(to_dir, "kallsyms");
1943 kcore_copy__free_phdrs(&kci);
1944 kcore_copy__free_syms(&kci);
1949 int kcore_extract__create(struct kcore_extract *kce)
1952 struct kcore extract;
1954 int idx = 0, err = -1;
1955 off_t offset = page_size, sz;
1957 if (kcore__open(&kcore, kce->kcore_filename))
1960 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1961 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1962 goto out_kcore_close;
1964 if (kcore__copy_hdr(&kcore, &extract, count))
1965 goto out_extract_close;
1967 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1968 goto out_extract_close;
1970 sz = kcore__write(&extract);
1971 if (sz < 0 || sz > offset)
1972 goto out_extract_close;
1974 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1975 goto out_extract_close;
1980 kcore__close(&extract);
1982 unlink(kce->extract_filename);
1984 kcore__close(&kcore);
1989 void kcore_extract__delete(struct kcore_extract *kce)
1991 unlink(kce->extract_filename);
1994 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1996 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
2002 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2003 tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2004 tmp->addr.a32[SDT_NOTE_IDX_BASE];
2006 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2007 tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2008 tmp->addr.a64[SDT_NOTE_IDX_BASE];
2011 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2017 if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2018 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2019 else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2020 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2024 * populate_sdt_note : Parse raw data and identify SDT note
2025 * @elf: elf of the opened file
2026 * @data: raw data of a section with description offset applied
2027 * @len: note description size
2028 * @type: type of the note
2029 * @sdt_notes: List to add the SDT note
2031 * Responsible for parsing the @data in section .note.stapsdt in @elf and
2032 * if its an SDT note, it appends to @sdt_notes list.
2034 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2035 struct list_head *sdt_notes)
2037 const char *provider, *name, *args;
2038 struct sdt_note *tmp = NULL;
2044 Elf64_Addr a64[NR_ADDR];
2045 Elf32_Addr a32[NR_ADDR];
2049 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2050 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2051 .d_off = 0, .d_align = 0
2054 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2055 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2059 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2065 INIT_LIST_HEAD(&tmp->note_list);
2067 if (len < dst.d_size + 3)
2070 /* Translation from file representation to memory representation */
2071 if (gelf_xlatetom(*elf, &dst, &src,
2072 elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2073 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2077 /* Populate the fields of sdt_note */
2078 provider = data + dst.d_size;
2080 name = (const char *)memchr(provider, '\0', data + len - provider);
2084 tmp->provider = strdup(provider);
2085 if (!tmp->provider) {
2089 tmp->name = strdup(name);
2095 args = memchr(name, '\0', data + len - name);
2098 * There is no argument if:
2099 * - We reached the end of the note;
2100 * - There is not enough room to hold a potential string;
2101 * - The argument string is empty or just contains ':'.
2103 if (args == NULL || data + len - args < 2 ||
2104 args[1] == ':' || args[1] == '\0')
2107 tmp->args = strdup(++args);
2114 if (gelf_getclass(*elf) == ELFCLASS32) {
2115 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2118 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2122 if (!gelf_getehdr(*elf, &ehdr)) {
2123 pr_debug("%s : cannot get elf header.\n", __func__);
2128 /* Adjust the prelink effect :
2129 * Find out the .stapsdt.base section.
2130 * This scn will help us to handle prelinking (if present).
2131 * Compare the retrieved file offset of the base section with the
2132 * base address in the description of the SDT note. If its different,
2133 * then accordingly, adjust the note location.
2135 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2136 sdt_adjust_loc(tmp, shdr.sh_offset);
2138 /* Adjust reference counter offset */
2139 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2140 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2142 list_add_tail(&tmp->note_list, sdt_notes);
2150 zfree(&tmp->provider);
2158 * construct_sdt_notes_list : constructs a list of SDT notes
2159 * @elf : elf to look into
2160 * @sdt_notes : empty list_head
2162 * Scans the sections in 'elf' for the section
2163 * .note.stapsdt. It, then calls populate_sdt_note to find
2164 * out the SDT events and populates the 'sdt_notes'.
2166 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2169 Elf_Scn *scn = NULL;
2172 size_t shstrndx, next;
2174 size_t name_off, desc_off, offset;
2177 if (gelf_getehdr(elf, &ehdr) == NULL) {
2181 if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2186 /* Look for the required section */
2187 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2193 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2198 data = elf_getdata(scn, NULL);
2200 /* Get the SDT notes */
2201 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2202 &desc_off)) > 0; offset = next) {
2203 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2204 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2205 sizeof(SDT_NOTE_NAME))) {
2206 /* Check the type of the note */
2207 if (nhdr.n_type != SDT_NOTE_TYPE)
2210 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2211 nhdr.n_descsz, sdt_notes);
2216 if (list_empty(sdt_notes))
2224 * get_sdt_note_list : Wrapper to construct a list of sdt notes
2225 * @head : empty list_head
2226 * @target : file to find SDT notes from
2228 * This opens the file, initializes
2229 * the ELF and then calls construct_sdt_notes_list.
2231 int get_sdt_note_list(struct list_head *head, const char *target)
2236 fd = open(target, O_RDONLY);
2240 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2245 ret = construct_sdt_notes_list(elf, head);
2253 * cleanup_sdt_note_list : free the sdt notes' list
2254 * @sdt_notes: sdt notes' list
2256 * Free up the SDT notes in @sdt_notes.
2257 * Returns the number of SDT notes free'd.
2259 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2261 struct sdt_note *tmp, *pos;
2264 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2265 list_del_init(&pos->note_list);
2267 zfree(&pos->provider);
2275 * sdt_notes__get_count: Counts the number of sdt events
2276 * @start: list_head to sdt_notes list
2278 * Returns the number of SDT notes in a list
2280 int sdt_notes__get_count(struct list_head *start)
2282 struct sdt_note *sdt_ptr;
2285 list_for_each_entry(sdt_ptr, start, note_list)
2291 void symbol__elf_init(void)
2293 elf_version(EV_CURRENT);