1 // SPDX-License-Identifier: GPL-2.0
11 #include "map_groups.h"
14 #include "demangle-java.h"
15 #include "demangle-rust.h"
20 #include <linux/ctype.h>
21 #include <linux/zalloc.h>
22 #include <symbol/kallsyms.h>
25 #define EM_AARCH64 183 /* ARM 64 bit */
28 #ifndef ELF32_ST_VISIBILITY
29 #define ELF32_ST_VISIBILITY(o) ((o) & 0x03)
32 /* For ELF64 the definitions are the same. */
33 #ifndef ELF64_ST_VISIBILITY
34 #define ELF64_ST_VISIBILITY(o) ELF32_ST_VISIBILITY (o)
37 /* How to extract information held in the st_other field. */
38 #ifndef GELF_ST_VISIBILITY
39 #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)
42 typedef Elf64_Nhdr GElf_Nhdr;
45 #define DMGL_NO_OPTS 0 /* For readability... */
46 #define DMGL_PARAMS (1 << 0) /* Include function args */
47 #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */
50 #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
51 extern char *cplus_demangle(const char *, int);
53 static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
55 return cplus_demangle(c, i);
59 static inline char *bfd_demangle(void __maybe_unused *v,
60 const char __maybe_unused *c,
66 #define PACKAGE 'perf'
71 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
72 static int elf_getphdrnum(Elf *elf, size_t *dst)
77 ehdr = gelf_getehdr(elf, &gehdr);
87 #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
88 static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
90 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
95 #ifndef NT_GNU_BUILD_ID
96 #define NT_GNU_BUILD_ID 3
100 * elf_symtab__for_each_symbol - iterate thru all the symbols
102 * @syms: struct elf_symtab instance to iterate
104 * @sym: GElf_Sym iterator
106 #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
107 for (idx = 0, gelf_getsym(syms, idx, &sym);\
109 idx++, gelf_getsym(syms, idx, &sym))
111 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
113 return GELF_ST_TYPE(sym->st_info);
116 static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)
118 return GELF_ST_VISIBILITY(sym->st_other);
121 #ifndef STT_GNU_IFUNC
122 #define STT_GNU_IFUNC 10
125 static inline int elf_sym__is_function(const GElf_Sym *sym)
127 return (elf_sym__type(sym) == STT_FUNC ||
128 elf_sym__type(sym) == STT_GNU_IFUNC) &&
130 sym->st_shndx != SHN_UNDEF;
133 static inline bool elf_sym__is_object(const GElf_Sym *sym)
135 return elf_sym__type(sym) == STT_OBJECT &&
137 sym->st_shndx != SHN_UNDEF;
140 static inline int elf_sym__is_label(const GElf_Sym *sym)
142 return elf_sym__type(sym) == STT_NOTYPE &&
144 sym->st_shndx != SHN_UNDEF &&
145 sym->st_shndx != SHN_ABS &&
146 elf_sym__visibility(sym) != STV_HIDDEN &&
147 elf_sym__visibility(sym) != STV_INTERNAL;
150 static bool elf_sym__filter(GElf_Sym *sym)
152 return elf_sym__is_function(sym) || elf_sym__is_object(sym);
155 static inline const char *elf_sym__name(const GElf_Sym *sym,
156 const Elf_Data *symstrs)
158 return symstrs->d_buf + sym->st_name;
161 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
162 const Elf_Data *secstrs)
164 return secstrs->d_buf + shdr->sh_name;
167 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
168 const Elf_Data *secstrs)
170 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
173 static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
174 const Elf_Data *secstrs)
176 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
179 static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)
181 return elf_sec__is_text(shdr, secstrs) ||
182 elf_sec__is_data(shdr, secstrs);
185 static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
191 while ((sec = elf_nextscn(elf, sec)) != NULL) {
192 gelf_getshdr(sec, &shdr);
194 if ((addr >= shdr.sh_addr) &&
195 (addr < (shdr.sh_addr + shdr.sh_size)))
204 Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
205 GElf_Shdr *shp, const char *name, size_t *idx)
210 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
211 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
214 while ((sec = elf_nextscn(elf, sec)) != NULL) {
217 gelf_getshdr(sec, shp);
218 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
219 if (str && !strcmp(name, str)) {
230 static bool want_demangle(bool is_kernel_sym)
232 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
235 static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
237 int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
238 char *demangled = NULL;
241 * We need to figure out if the object was created from C++ sources
242 * DWARF DW_compile_unit has this, but we don't always have access
245 if (!want_demangle(dso->kernel || kmodule))
248 demangled = bfd_demangle(NULL, elf_name, demangle_flags);
249 if (demangled == NULL)
250 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
251 else if (rust_is_mangled(demangled))
253 * Input to Rust demangling is the BFD-demangled
254 * name which it Rust-demangles in place.
256 rust_demangle_sym(demangled);
261 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
262 for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
264 ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
266 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
267 for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
269 ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
272 * We need to check if we have a .dynsym, so that we can handle the
273 * .plt, synthesizing its symbols, that aren't on the symtabs (be it
274 * .dynsym or .symtab).
275 * And always look at the original dso, not at debuginfo packages, that
276 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
278 int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)
280 uint32_t nr_rel_entries, idx;
282 u64 plt_offset, plt_header_size, plt_entry_size;
285 GElf_Shdr shdr_rel_plt, shdr_dynsym;
286 Elf_Data *reldata, *syms, *symstrs;
287 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
290 char sympltname[1024];
292 int nr = 0, symidx, err = 0;
300 scn_dynsym = ss->dynsym;
301 shdr_dynsym = ss->dynshdr;
302 dynsym_idx = ss->dynsym_idx;
304 if (scn_dynsym == NULL)
307 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
309 if (scn_plt_rel == NULL) {
310 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
312 if (scn_plt_rel == NULL)
318 if (shdr_rel_plt.sh_link != dynsym_idx)
321 if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
325 * Fetch the relocation section to find the idxes to the GOT
326 * and the symbols in the .dynsym they refer to.
328 reldata = elf_getdata(scn_plt_rel, NULL);
332 syms = elf_getdata(scn_dynsym, NULL);
336 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
337 if (scn_symstrs == NULL)
340 symstrs = elf_getdata(scn_symstrs, NULL);
344 if (symstrs->d_size == 0)
347 nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
348 plt_offset = shdr_plt.sh_offset;
349 switch (ehdr.e_machine) {
351 plt_header_size = 20;
356 plt_header_size = 32;
361 plt_header_size = 48;
366 plt_header_size = 128;
370 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */
371 plt_header_size = shdr_plt.sh_entsize;
372 plt_entry_size = shdr_plt.sh_entsize;
375 plt_offset += plt_header_size;
377 if (shdr_rel_plt.sh_type == SHT_RELA) {
378 GElf_Rela pos_mem, *pos;
380 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
382 const char *elf_name = NULL;
383 char *demangled = NULL;
384 symidx = GELF_R_SYM(pos->r_info);
385 gelf_getsym(syms, symidx, &sym);
387 elf_name = elf_sym__name(&sym, symstrs);
388 demangled = demangle_sym(dso, 0, elf_name);
389 if (demangled != NULL)
390 elf_name = demangled;
391 snprintf(sympltname, sizeof(sympltname),
395 f = symbol__new(plt_offset, plt_entry_size,
396 STB_GLOBAL, STT_FUNC, sympltname);
400 plt_offset += plt_entry_size;
401 symbols__insert(&dso->symbols, f);
404 } else if (shdr_rel_plt.sh_type == SHT_REL) {
405 GElf_Rel pos_mem, *pos;
406 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
408 const char *elf_name = NULL;
409 char *demangled = NULL;
410 symidx = GELF_R_SYM(pos->r_info);
411 gelf_getsym(syms, symidx, &sym);
413 elf_name = elf_sym__name(&sym, symstrs);
414 demangled = demangle_sym(dso, 0, elf_name);
415 if (demangled != NULL)
416 elf_name = demangled;
417 snprintf(sympltname, sizeof(sympltname),
421 f = symbol__new(plt_offset, plt_entry_size,
422 STB_GLOBAL, STT_FUNC, sympltname);
426 plt_offset += plt_entry_size;
427 symbols__insert(&dso->symbols, f);
436 pr_debug("%s: problems reading %s PLT info.\n",
437 __func__, dso->long_name);
441 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
443 return demangle_sym(dso, kmodule, elf_name);
447 * Align offset to 4 bytes as needed for note name and descriptor data.
449 #define NOTE_ALIGN(n) (((n) + 3) & -4U)
451 static int elf_read_build_id(Elf *elf, void *bf, size_t size)
461 if (size < BUILD_ID_SIZE)
468 if (gelf_getehdr(elf, &ehdr) == NULL) {
469 pr_err("%s: cannot get elf header.\n", __func__);
474 * Check following sections for notes:
475 * '.note.gnu.build-id'
477 * '.note' (VDSO specific)
480 sec = elf_section_by_name(elf, &ehdr, &shdr,
481 ".note.gnu.build-id", NULL);
485 sec = elf_section_by_name(elf, &ehdr, &shdr,
490 sec = elf_section_by_name(elf, &ehdr, &shdr,
499 data = elf_getdata(sec, NULL);
504 while (ptr < (data->d_buf + data->d_size)) {
505 GElf_Nhdr *nhdr = ptr;
506 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
507 descsz = NOTE_ALIGN(nhdr->n_descsz);
510 ptr += sizeof(*nhdr);
513 if (nhdr->n_type == NT_GNU_BUILD_ID &&
514 nhdr->n_namesz == sizeof("GNU")) {
515 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
516 size_t sz = min(size, descsz);
518 memset(bf + sz, 0, size - sz);
530 int filename__read_build_id(const char *filename, void *bf, size_t size)
535 if (size < BUILD_ID_SIZE)
538 fd = open(filename, O_RDONLY);
542 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
544 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
548 err = elf_read_build_id(elf, bf, size);
557 int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
561 if (size < BUILD_ID_SIZE)
564 fd = open(filename, O_RDONLY);
571 size_t namesz, descsz;
573 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
576 namesz = NOTE_ALIGN(nhdr.n_namesz);
577 descsz = NOTE_ALIGN(nhdr.n_descsz);
578 if (nhdr.n_type == NT_GNU_BUILD_ID &&
579 nhdr.n_namesz == sizeof("GNU")) {
580 if (read(fd, bf, namesz) != (ssize_t)namesz)
582 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
583 size_t sz = min(descsz, size);
584 if (read(fd, build_id, sz) == (ssize_t)sz) {
585 memset(build_id + sz, 0, size - sz);
589 } else if (read(fd, bf, descsz) != (ssize_t)descsz)
592 int n = namesz + descsz;
594 if (n > (int)sizeof(bf)) {
596 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
597 __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
599 if (read(fd, bf, n) != n)
608 int filename__read_debuglink(const char *filename, char *debuglink,
619 fd = open(filename, O_RDONLY);
623 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
625 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
633 if (gelf_getehdr(elf, &ehdr) == NULL) {
634 pr_err("%s: cannot get elf header.\n", __func__);
638 sec = elf_section_by_name(elf, &ehdr, &shdr,
639 ".gnu_debuglink", NULL);
643 data = elf_getdata(sec, NULL);
647 /* the start of this section is a zero-terminated string */
648 strncpy(debuglink, data->d_buf, size);
660 static int dso__swap_init(struct dso *dso, unsigned char eidata)
662 static unsigned int const endian = 1;
664 dso->needs_swap = DSO_SWAP__NO;
668 /* We are big endian, DSO is little endian. */
669 if (*(unsigned char const *)&endian != 1)
670 dso->needs_swap = DSO_SWAP__YES;
674 /* We are little endian, DSO is big endian. */
675 if (*(unsigned char const *)&endian != 0)
676 dso->needs_swap = DSO_SWAP__YES;
680 pr_err("unrecognized DSO data encoding %d\n", eidata);
687 bool symsrc__possibly_runtime(struct symsrc *ss)
689 return ss->dynsym || ss->opdsec;
692 bool symsrc__has_symtab(struct symsrc *ss)
694 return ss->symtab != NULL;
697 void symsrc__destroy(struct symsrc *ss)
704 bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
706 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
709 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
710 enum dso_binary_type type)
716 if (dso__needs_decompress(dso)) {
717 fd = dso__decompress_kmodule_fd(dso, name);
721 type = dso->symtab_type;
723 fd = open(name, O_RDONLY);
725 dso->load_errno = errno;
730 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
732 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
733 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
737 if (gelf_getehdr(elf, &ehdr) == NULL) {
738 dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
739 pr_debug("%s: cannot get elf header.\n", __func__);
743 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
744 dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
748 /* Always reject images with a mismatched build-id: */
749 if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
750 u8 build_id[BUILD_ID_SIZE];
752 if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
753 dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
757 if (!dso__build_id_equal(dso, build_id)) {
758 pr_debug("%s: build id mismatch for %s.\n", __func__, name);
759 dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
764 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
766 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
768 if (ss->symshdr.sh_type != SHT_SYMTAB)
772 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
774 if (ss->dynshdr.sh_type != SHT_DYNSYM)
778 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
780 if (ss->opdshdr.sh_type != SHT_PROGBITS)
783 if (dso->kernel == DSO_TYPE_USER)
784 ss->adjust_symbols = true;
786 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
788 ss->name = strdup(name);
790 dso->load_errno = errno;
809 * ref_reloc_sym_not_found - has kernel relocation symbol been found.
810 * @kmap: kernel maps and relocation reference symbol
812 * This function returns %true if we are dealing with the kernel maps and the
813 * relocation reference symbol has not yet been found. Otherwise %false is
816 static bool ref_reloc_sym_not_found(struct kmap *kmap)
818 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
819 !kmap->ref_reloc_sym->unrelocated_addr;
823 * ref_reloc - kernel relocation offset.
824 * @kmap: kernel maps and relocation reference symbol
826 * This function returns the offset of kernel addresses as determined by using
827 * the relocation reference symbol i.e. if the kernel has not been relocated
828 * then the return value is zero.
830 static u64 ref_reloc(struct kmap *kmap)
832 if (kmap && kmap->ref_reloc_sym &&
833 kmap->ref_reloc_sym->unrelocated_addr)
834 return kmap->ref_reloc_sym->addr -
835 kmap->ref_reloc_sym->unrelocated_addr;
839 void __weak arch__sym_update(struct symbol *s __maybe_unused,
840 GElf_Sym *sym __maybe_unused) { }
842 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
843 GElf_Sym *sym, GElf_Shdr *shdr,
844 struct map_groups *kmaps, struct kmap *kmap,
845 struct dso **curr_dsop, struct map **curr_mapp,
846 const char *section_name,
847 bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
849 struct dso *curr_dso = *curr_dsop;
850 struct map *curr_map;
851 char dso_name[PATH_MAX];
853 /* Adjust symbol to map to file offset */
854 if (adjust_kernel_syms)
855 sym->st_value -= shdr->sh_addr - shdr->sh_offset;
857 if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0)
860 if (strcmp(section_name, ".text") == 0) {
862 * The initial kernel mapping is based on
863 * kallsyms and identity maps. Overwrite it to
864 * map to the kernel dso.
866 if (*remap_kernel && dso->kernel) {
867 *remap_kernel = false;
868 map->start = shdr->sh_addr + ref_reloc(kmap);
869 map->end = map->start + shdr->sh_size;
870 map->pgoff = shdr->sh_offset;
871 map->map_ip = map__map_ip;
872 map->unmap_ip = map__unmap_ip;
873 /* Ensure maps are correctly ordered */
876 map_groups__remove(kmaps, map);
877 map_groups__insert(kmaps, map);
883 * The initial module mapping is based on
884 * /proc/modules mapped to offset zero.
885 * Overwrite it to map to the module dso.
887 if (*remap_kernel && kmodule) {
888 *remap_kernel = false;
889 map->pgoff = shdr->sh_offset;
900 snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name);
902 curr_map = map_groups__find_by_name(kmaps, dso_name);
903 if (curr_map == NULL) {
904 u64 start = sym->st_value;
907 start += map->start + shdr->sh_offset;
909 curr_dso = dso__new(dso_name);
910 if (curr_dso == NULL)
912 curr_dso->kernel = dso->kernel;
913 curr_dso->long_name = dso->long_name;
914 curr_dso->long_name_len = dso->long_name_len;
915 curr_map = map__new2(start, curr_dso);
917 if (curr_map == NULL)
920 if (adjust_kernel_syms) {
921 curr_map->start = shdr->sh_addr + ref_reloc(kmap);
922 curr_map->end = curr_map->start + shdr->sh_size;
923 curr_map->pgoff = shdr->sh_offset;
925 curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
927 curr_dso->symtab_type = dso->symtab_type;
928 map_groups__insert(kmaps, curr_map);
930 * Add it before we drop the referece to curr_map, i.e. while
931 * we still are sure to have a reference to this DSO via
934 dsos__add(&map->groups->machine->dsos, curr_dso);
935 /* kmaps already got it */
937 dso__set_loaded(curr_dso);
938 *curr_mapp = curr_map;
939 *curr_dsop = curr_dso;
941 *curr_dsop = curr_map->dso;
946 int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
947 struct symsrc *runtime_ss, int kmodule)
949 struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
950 struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
951 struct map *curr_map = map;
952 struct dso *curr_dso = dso;
953 Elf_Data *symstrs, *secstrs;
960 Elf_Data *syms, *opddata = NULL;
962 Elf_Scn *sec, *sec_strndx;
965 bool remap_kernel = false, adjust_kernel_syms = false;
970 dso->symtab_type = syms_ss->type;
971 dso->is_64_bit = syms_ss->is_64_bit;
972 dso->rel = syms_ss->ehdr.e_type == ET_REL;
975 * Modules may already have symbols from kallsyms, but those symbols
976 * have the wrong values for the dso maps, so remove them.
978 if (kmodule && syms_ss->symtab)
979 symbols__delete(&dso->symbols);
981 if (!syms_ss->symtab) {
983 * If the vmlinux is stripped, fail so we will fall back
984 * to using kallsyms. The vmlinux runtime symbols aren't
990 syms_ss->symtab = syms_ss->dynsym;
991 syms_ss->symshdr = syms_ss->dynshdr;
995 ehdr = syms_ss->ehdr;
996 sec = syms_ss->symtab;
997 shdr = syms_ss->symshdr;
999 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
1001 dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
1003 if (runtime_ss->opdsec)
1004 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
1006 syms = elf_getdata(sec, NULL);
1010 sec = elf_getscn(elf, shdr.sh_link);
1014 symstrs = elf_getdata(sec, NULL);
1015 if (symstrs == NULL)
1018 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
1019 if (sec_strndx == NULL)
1022 secstrs = elf_getdata(sec_strndx, NULL);
1023 if (secstrs == NULL)
1026 nr_syms = shdr.sh_size / shdr.sh_entsize;
1028 memset(&sym, 0, sizeof(sym));
1031 * The kernel relocation symbol is needed in advance in order to adjust
1032 * kernel maps correctly.
1034 if (ref_reloc_sym_not_found(kmap)) {
1035 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1036 const char *elf_name = elf_sym__name(&sym, symstrs);
1038 if (strcmp(elf_name, kmap->ref_reloc_sym->name))
1040 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
1041 map->reloc = kmap->ref_reloc_sym->addr -
1042 kmap->ref_reloc_sym->unrelocated_addr;
1048 * Handle any relocation of vdso necessary because older kernels
1049 * attempted to prelink vdso to its virtual address.
1051 if (dso__is_vdso(dso))
1052 map->reloc = map->start - dso->text_offset;
1054 dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
1056 * Initial kernel and module mappings do not map to the dso.
1059 if (dso->kernel || kmodule) {
1060 remap_kernel = true;
1061 adjust_kernel_syms = dso->adjust_symbols;
1063 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
1065 const char *elf_name = elf_sym__name(&sym, symstrs);
1066 char *demangled = NULL;
1067 int is_label = elf_sym__is_label(&sym);
1068 const char *section_name;
1069 bool used_opd = false;
1071 if (!is_label && !elf_sym__filter(&sym))
1074 /* Reject ARM ELF "mapping symbols": these aren't unique and
1075 * don't identify functions, so will confuse the profile
1077 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
1078 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
1079 && (elf_name[2] == '\0' || elf_name[2] == '.'))
1083 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
1084 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
1085 u64 *opd = opddata->d_buf + offset;
1086 sym.st_value = DSO__SWAP(dso, u64, *opd);
1087 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
1092 * When loading symbols in a data mapping, ABS symbols (which
1093 * has a value of SHN_ABS in its st_shndx) failed at
1094 * elf_getscn(). And it marks the loading as a failure so
1095 * already loaded symbols cannot be fixed up.
1097 * I'm not sure what should be done. Just ignore them for now.
1100 if (sym.st_shndx == SHN_ABS)
1103 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
1107 gelf_getshdr(sec, &shdr);
1109 if (is_label && !elf_sec__filter(&shdr, secstrs))
1112 section_name = elf_sec__name(&shdr, secstrs);
1114 /* On ARM, symbols for thumb functions have 1 added to
1115 * the symbol address as a flag - remove it */
1116 if ((ehdr.e_machine == EM_ARM) &&
1117 (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&
1121 if (dso->kernel || kmodule) {
1122 if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
1123 section_name, adjust_kernel_syms, kmodule, &remap_kernel))
1125 } else if ((used_opd && runtime_ss->adjust_symbols) ||
1126 (!used_opd && syms_ss->adjust_symbols)) {
1127 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
1128 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
1129 (u64)sym.st_value, (u64)shdr.sh_addr,
1130 (u64)shdr.sh_offset);
1131 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
1134 demangled = demangle_sym(dso, kmodule, elf_name);
1135 if (demangled != NULL)
1136 elf_name = demangled;
1138 f = symbol__new(sym.st_value, sym.st_size,
1139 GELF_ST_BIND(sym.st_info),
1140 GELF_ST_TYPE(sym.st_info), elf_name);
1145 arch__sym_update(f, &sym);
1147 __symbols__insert(&curr_dso->symbols, f, dso->kernel);
1152 * For misannotated, zeroed, ASM function sizes.
1155 symbols__fixup_end(&dso->symbols);
1156 symbols__fixup_duplicate(&dso->symbols);
1159 * We need to fixup this here too because we create new
1160 * maps here, for things like vsyscall sections.
1162 map_groups__fixup_end(kmaps);
1170 static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
1177 if (elf_getphdrnum(elf, &phdrnum))
1180 for (i = 0; i < phdrnum; i++) {
1181 if (gelf_getphdr(elf, i, &phdr) == NULL)
1183 if (phdr.p_type != PT_LOAD)
1186 if (!(phdr.p_flags & PF_X))
1189 if (!(phdr.p_flags & PF_R))
1192 sz = min(phdr.p_memsz, phdr.p_filesz);
1195 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
1202 int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
1208 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1213 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
1215 err = elf_read_maps(elf, exe, mapfn, data);
1221 enum dso_type dso__type_fd(int fd)
1223 enum dso_type dso_type = DSO__TYPE_UNKNOWN;
1228 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
1233 if (ek != ELF_K_ELF)
1236 if (gelf_getclass(elf) == ELFCLASS64) {
1237 dso_type = DSO__TYPE_64BIT;
1241 if (gelf_getehdr(elf, &ehdr) == NULL)
1244 if (ehdr.e_machine == EM_X86_64)
1245 dso_type = DSO__TYPE_X32BIT;
1247 dso_type = DSO__TYPE_32BIT;
1254 static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
1259 char *buf = malloc(page_size);
1264 if (lseek(to, to_offs, SEEK_SET) != to_offs)
1267 if (lseek(from, from_offs, SEEK_SET) != from_offs)
1274 /* Use read because mmap won't work on proc files */
1275 r = read(from, buf, n);
1281 r = write(to, buf, n);
1302 static int kcore__open(struct kcore *kcore, const char *filename)
1306 kcore->fd = open(filename, O_RDONLY);
1307 if (kcore->fd == -1)
1310 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
1314 kcore->elfclass = gelf_getclass(kcore->elf);
1315 if (kcore->elfclass == ELFCLASSNONE)
1318 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
1325 elf_end(kcore->elf);
1331 static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
1334 kcore->elfclass = elfclass;
1337 kcore->fd = mkstemp(filename);
1339 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
1340 if (kcore->fd == -1)
1343 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
1347 if (!gelf_newehdr(kcore->elf, elfclass))
1350 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
1355 elf_end(kcore->elf);
1362 static void kcore__close(struct kcore *kcore)
1364 elf_end(kcore->elf);
1368 static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
1370 GElf_Ehdr *ehdr = &to->ehdr;
1371 GElf_Ehdr *kehdr = &from->ehdr;
1373 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
1374 ehdr->e_type = kehdr->e_type;
1375 ehdr->e_machine = kehdr->e_machine;
1376 ehdr->e_version = kehdr->e_version;
1379 ehdr->e_flags = kehdr->e_flags;
1380 ehdr->e_phnum = count;
1381 ehdr->e_shentsize = 0;
1383 ehdr->e_shstrndx = 0;
1385 if (from->elfclass == ELFCLASS32) {
1386 ehdr->e_phoff = sizeof(Elf32_Ehdr);
1387 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
1388 ehdr->e_phentsize = sizeof(Elf32_Phdr);
1390 ehdr->e_phoff = sizeof(Elf64_Ehdr);
1391 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
1392 ehdr->e_phentsize = sizeof(Elf64_Phdr);
1395 if (!gelf_update_ehdr(to->elf, ehdr))
1398 if (!gelf_newphdr(to->elf, count))
1404 static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
1409 .p_flags = PF_R | PF_W | PF_X,
1415 .p_align = page_size,
1418 if (!gelf_update_phdr(kcore->elf, idx, &phdr))
1424 static off_t kcore__write(struct kcore *kcore)
1426 return elf_update(kcore->elf, ELF_C_WRITE);
1434 struct list_head node;
1435 struct phdr_data *remaps;
1440 struct list_head node;
1443 struct kcore_copy_info {
1449 u64 last_module_symbol;
1451 struct list_head phdrs;
1452 struct list_head syms;
1455 #define kcore_copy__for_each_phdr(k, p) \
1456 list_for_each_entry((p), &(k)->phdrs, node)
1458 static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)
1460 struct phdr_data *p = zalloc(sizeof(*p));
1471 static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,
1475 struct phdr_data *p = phdr_data__new(addr, len, offset);
1478 list_add_tail(&p->node, &kci->phdrs);
1483 static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)
1485 struct phdr_data *p, *tmp;
1487 list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {
1488 list_del_init(&p->node);
1493 static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,
1496 struct sym_data *s = zalloc(sizeof(*s));
1500 list_add_tail(&s->node, &kci->syms);
1506 static void kcore_copy__free_syms(struct kcore_copy_info *kci)
1508 struct sym_data *s, *tmp;
1510 list_for_each_entry_safe(s, tmp, &kci->syms, node) {
1511 list_del_init(&s->node);
1516 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
1519 struct kcore_copy_info *kci = arg;
1521 if (!kallsyms__is_function(type))
1524 if (strchr(name, '[')) {
1525 if (start > kci->last_module_symbol)
1526 kci->last_module_symbol = start;
1530 if (!kci->first_symbol || start < kci->first_symbol)
1531 kci->first_symbol = start;
1533 if (!kci->last_symbol || start > kci->last_symbol)
1534 kci->last_symbol = start;
1536 if (!strcmp(name, "_stext")) {
1541 if (!strcmp(name, "_etext")) {
1546 if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))
1552 static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
1555 char kallsyms_filename[PATH_MAX];
1557 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
1559 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
1562 if (kallsyms__parse(kallsyms_filename, kci,
1563 kcore_copy__process_kallsyms) < 0)
1569 static int kcore_copy__process_modules(void *arg,
1570 const char *name __maybe_unused,
1571 u64 start, u64 size __maybe_unused)
1573 struct kcore_copy_info *kci = arg;
1575 if (!kci->first_module || start < kci->first_module)
1576 kci->first_module = start;
1581 static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
1584 char modules_filename[PATH_MAX];
1586 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
1588 if (symbol__restricted_filename(modules_filename, "/proc/modules"))
1591 if (modules__parse(modules_filename, kci,
1592 kcore_copy__process_modules) < 0)
1598 static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,
1599 u64 pgoff, u64 s, u64 e)
1603 if (s < start || s >= end)
1606 offset = (s - start) + pgoff;
1607 len = e < end ? e - s : end - s;
1609 return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;
1612 static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
1614 struct kcore_copy_info *kci = data;
1615 u64 end = start + len;
1616 struct sym_data *sdat;
1618 if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))
1621 if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,
1622 kci->last_module_symbol))
1625 list_for_each_entry(sdat, &kci->syms, node) {
1626 u64 s = round_down(sdat->addr, page_size);
1628 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))
1635 static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
1637 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
1643 static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
1645 struct phdr_data *p, *k = NULL;
1651 /* Find phdr that corresponds to the kernel map (contains stext) */
1652 kcore_copy__for_each_phdr(kci, p) {
1653 u64 pend = p->addr + p->len - 1;
1655 if (p->addr <= kci->stext && pend >= kci->stext) {
1664 kend = k->offset + k->len;
1666 /* Find phdrs that remap the kernel */
1667 kcore_copy__for_each_phdr(kci, p) {
1668 u64 pend = p->offset + p->len;
1673 if (p->offset >= k->offset && pend <= kend)
1678 static void kcore_copy__layout(struct kcore_copy_info *kci)
1680 struct phdr_data *p;
1683 kcore_copy__find_remaps(kci);
1685 kcore_copy__for_each_phdr(kci, p) {
1693 kcore_copy__for_each_phdr(kci, p) {
1694 struct phdr_data *k = p->remaps;
1697 p->rel = p->offset - k->offset + k->rel;
1701 static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
1704 if (kcore_copy__parse_kallsyms(kci, dir))
1707 if (kcore_copy__parse_modules(kci, dir))
1711 kci->stext = round_down(kci->stext, page_size);
1713 kci->stext = round_down(kci->first_symbol, page_size);
1716 kci->etext = round_up(kci->etext, page_size);
1717 } else if (kci->last_symbol) {
1718 kci->etext = round_up(kci->last_symbol, page_size);
1719 kci->etext += page_size;
1722 kci->first_module = round_down(kci->first_module, page_size);
1724 if (kci->last_module_symbol) {
1725 kci->last_module_symbol = round_up(kci->last_module_symbol,
1727 kci->last_module_symbol += page_size;
1730 if (!kci->stext || !kci->etext)
1733 if (kci->first_module && !kci->last_module_symbol)
1736 if (kcore_copy__read_maps(kci, elf))
1739 kcore_copy__layout(kci);
1744 static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
1747 char from_filename[PATH_MAX];
1748 char to_filename[PATH_MAX];
1750 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1751 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1753 return copyfile_mode(from_filename, to_filename, 0400);
1756 static int kcore_copy__unlink(const char *dir, const char *name)
1758 char filename[PATH_MAX];
1760 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
1762 return unlink(filename);
1765 static int kcore_copy__compare_fds(int from, int to)
1773 buf_from = malloc(page_size);
1774 buf_to = malloc(page_size);
1775 if (!buf_from || !buf_to)
1779 /* Use read because mmap won't work on proc files */
1780 ret = read(from, buf_from, page_size);
1789 if (readn(to, buf_to, len) != (int)len)
1792 if (memcmp(buf_from, buf_to, len))
1803 static int kcore_copy__compare_files(const char *from_filename,
1804 const char *to_filename)
1806 int from, to, err = -1;
1808 from = open(from_filename, O_RDONLY);
1812 to = open(to_filename, O_RDONLY);
1814 goto out_close_from;
1816 err = kcore_copy__compare_fds(from, to);
1824 static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
1827 char from_filename[PATH_MAX];
1828 char to_filename[PATH_MAX];
1830 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
1831 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
1833 return kcore_copy__compare_files(from_filename, to_filename);
1837 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.
1838 * @from_dir: from directory
1839 * @to_dir: to directory
1841 * This function copies kallsyms, modules and kcore files from one directory to
1842 * another. kallsyms and modules are copied entirely. Only code segments are
1843 * copied from kcore. It is assumed that two segments suffice: one for the
1844 * kernel proper and one for all the modules. The code segments are determined
1845 * from kallsyms and modules files. The kernel map starts at _stext or the
1846 * lowest function symbol, and ends at _etext or the highest function symbol.
1847 * The module map starts at the lowest module address and ends at the highest
1848 * module symbol. Start addresses are rounded down to the nearest page. End
1849 * addresses are rounded up to the nearest page. An extra page is added to the
1850 * highest kernel symbol and highest module symbol to, hopefully, encompass that
1851 * symbol too. Because it contains only code sections, the resulting kcore is
1852 * unusual. One significant peculiarity is that the mapping (start -> pgoff)
1853 * is not the same for the kernel map and the modules map. That happens because
1854 * the data is copied adjacently whereas the original kcore has gaps. Finally,
1855 * kallsyms and modules files are compared with their copies to check that
1856 * modules have not been loaded or unloaded while the copies were taking place.
1858 * Return: %0 on success, %-1 on failure.
1860 int kcore_copy(const char *from_dir, const char *to_dir)
1863 struct kcore extract;
1864 int idx = 0, err = -1;
1866 struct kcore_copy_info kci = { .stext = 0, };
1867 char kcore_filename[PATH_MAX];
1868 char extract_filename[PATH_MAX];
1869 struct phdr_data *p;
1871 INIT_LIST_HEAD(&kci.phdrs);
1872 INIT_LIST_HEAD(&kci.syms);
1874 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
1877 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
1878 goto out_unlink_kallsyms;
1880 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
1881 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
1883 if (kcore__open(&kcore, kcore_filename))
1884 goto out_unlink_modules;
1886 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
1887 goto out_kcore_close;
1889 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
1890 goto out_kcore_close;
1892 if (kcore__copy_hdr(&kcore, &extract, kci.phnum))
1893 goto out_extract_close;
1895 offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +
1896 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);
1897 offset = round_up(offset, page_size);
1899 kcore_copy__for_each_phdr(&kci, p) {
1900 off_t offs = p->rel + offset;
1902 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))
1903 goto out_extract_close;
1906 sz = kcore__write(&extract);
1907 if (sz < 0 || sz > offset)
1908 goto out_extract_close;
1910 kcore_copy__for_each_phdr(&kci, p) {
1911 off_t offs = p->rel + offset;
1915 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
1916 goto out_extract_close;
1919 if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
1920 goto out_extract_close;
1922 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
1923 goto out_extract_close;
1928 kcore__close(&extract);
1930 unlink(extract_filename);
1932 kcore__close(&kcore);
1935 kcore_copy__unlink(to_dir, "modules");
1936 out_unlink_kallsyms:
1938 kcore_copy__unlink(to_dir, "kallsyms");
1940 kcore_copy__free_phdrs(&kci);
1941 kcore_copy__free_syms(&kci);
1946 int kcore_extract__create(struct kcore_extract *kce)
1949 struct kcore extract;
1951 int idx = 0, err = -1;
1952 off_t offset = page_size, sz;
1954 if (kcore__open(&kcore, kce->kcore_filename))
1957 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
1958 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
1959 goto out_kcore_close;
1961 if (kcore__copy_hdr(&kcore, &extract, count))
1962 goto out_extract_close;
1964 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
1965 goto out_extract_close;
1967 sz = kcore__write(&extract);
1968 if (sz < 0 || sz > offset)
1969 goto out_extract_close;
1971 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
1972 goto out_extract_close;
1977 kcore__close(&extract);
1979 unlink(kce->extract_filename);
1981 kcore__close(&kcore);
1986 void kcore_extract__delete(struct kcore_extract *kce)
1988 unlink(kce->extract_filename);
1991 #ifdef HAVE_GELF_GETNOTE_SUPPORT
1993 static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)
1999 tmp->addr.a32[SDT_NOTE_IDX_LOC] =
2000 tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -
2001 tmp->addr.a32[SDT_NOTE_IDX_BASE];
2003 tmp->addr.a64[SDT_NOTE_IDX_LOC] =
2004 tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -
2005 tmp->addr.a64[SDT_NOTE_IDX_BASE];
2008 static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,
2014 if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])
2015 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2016 else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])
2017 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);
2021 * populate_sdt_note : Parse raw data and identify SDT note
2022 * @elf: elf of the opened file
2023 * @data: raw data of a section with description offset applied
2024 * @len: note description size
2025 * @type: type of the note
2026 * @sdt_notes: List to add the SDT note
2028 * Responsible for parsing the @data in section .note.stapsdt in @elf and
2029 * if its an SDT note, it appends to @sdt_notes list.
2031 static int populate_sdt_note(Elf **elf, const char *data, size_t len,
2032 struct list_head *sdt_notes)
2034 const char *provider, *name, *args;
2035 struct sdt_note *tmp = NULL;
2041 Elf64_Addr a64[NR_ADDR];
2042 Elf32_Addr a32[NR_ADDR];
2046 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
2047 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
2048 .d_off = 0, .d_align = 0
2051 .d_buf = (void *) data, .d_type = ELF_T_ADDR,
2052 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
2056 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
2062 INIT_LIST_HEAD(&tmp->note_list);
2064 if (len < dst.d_size + 3)
2067 /* Translation from file representation to memory representation */
2068 if (gelf_xlatetom(*elf, &dst, &src,
2069 elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
2070 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
2074 /* Populate the fields of sdt_note */
2075 provider = data + dst.d_size;
2077 name = (const char *)memchr(provider, '\0', data + len - provider);
2081 tmp->provider = strdup(provider);
2082 if (!tmp->provider) {
2086 tmp->name = strdup(name);
2092 args = memchr(name, '\0', data + len - name);
2095 * There is no argument if:
2096 * - We reached the end of the note;
2097 * - There is not enough room to hold a potential string;
2098 * - The argument string is empty or just contains ':'.
2100 if (args == NULL || data + len - args < 2 ||
2101 args[1] == ':' || args[1] == '\0')
2104 tmp->args = strdup(++args);
2111 if (gelf_getclass(*elf) == ELFCLASS32) {
2112 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
2115 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
2119 if (!gelf_getehdr(*elf, &ehdr)) {
2120 pr_debug("%s : cannot get elf header.\n", __func__);
2125 /* Adjust the prelink effect :
2126 * Find out the .stapsdt.base section.
2127 * This scn will help us to handle prelinking (if present).
2128 * Compare the retrieved file offset of the base section with the
2129 * base address in the description of the SDT note. If its different,
2130 * then accordingly, adjust the note location.
2132 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
2133 sdt_adjust_loc(tmp, shdr.sh_offset);
2135 /* Adjust reference counter offset */
2136 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))
2137 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);
2139 list_add_tail(&tmp->note_list, sdt_notes);
2147 zfree(&tmp->provider);
2155 * construct_sdt_notes_list : constructs a list of SDT notes
2156 * @elf : elf to look into
2157 * @sdt_notes : empty list_head
2159 * Scans the sections in 'elf' for the section
2160 * .note.stapsdt. It, then calls populate_sdt_note to find
2161 * out the SDT events and populates the 'sdt_notes'.
2163 static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
2166 Elf_Scn *scn = NULL;
2169 size_t shstrndx, next;
2171 size_t name_off, desc_off, offset;
2174 if (gelf_getehdr(elf, &ehdr) == NULL) {
2178 if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
2183 /* Look for the required section */
2184 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
2190 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
2195 data = elf_getdata(scn, NULL);
2197 /* Get the SDT notes */
2198 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
2199 &desc_off)) > 0; offset = next) {
2200 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
2201 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
2202 sizeof(SDT_NOTE_NAME))) {
2203 /* Check the type of the note */
2204 if (nhdr.n_type != SDT_NOTE_TYPE)
2207 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
2208 nhdr.n_descsz, sdt_notes);
2213 if (list_empty(sdt_notes))
2221 * get_sdt_note_list : Wrapper to construct a list of sdt notes
2222 * @head : empty list_head
2223 * @target : file to find SDT notes from
2225 * This opens the file, initializes
2226 * the ELF and then calls construct_sdt_notes_list.
2228 int get_sdt_note_list(struct list_head *head, const char *target)
2233 fd = open(target, O_RDONLY);
2237 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
2242 ret = construct_sdt_notes_list(elf, head);
2250 * cleanup_sdt_note_list : free the sdt notes' list
2251 * @sdt_notes: sdt notes' list
2253 * Free up the SDT notes in @sdt_notes.
2254 * Returns the number of SDT notes free'd.
2256 int cleanup_sdt_note_list(struct list_head *sdt_notes)
2258 struct sdt_note *tmp, *pos;
2261 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
2262 list_del_init(&pos->note_list);
2264 zfree(&pos->provider);
2272 * sdt_notes__get_count: Counts the number of sdt events
2273 * @start: list_head to sdt_notes list
2275 * Returns the number of SDT notes in a list
2277 int sdt_notes__get_count(struct list_head *start)
2279 struct sdt_note *sdt_ptr;
2282 list_for_each_entry(sdt_ptr, start, note_list)
2288 void symbol__elf_init(void)
2290 elf_version(EV_CURRENT);