// SPDX-License-Identifier: GPL-2.0 #include #include #include #include #include #include #include #include "dso.h" #include "map.h" #include "maps.h" #include "symbol.h" #include "symsrc.h" #include "demangle-ocaml.h" #include "demangle-java.h" #include "demangle-rust.h" #include "machine.h" #include "vdso.h" #include "debug.h" #include "util/copyfile.h" #include #include #include #include #include #ifndef EM_AARCH64 #define EM_AARCH64 183 /* ARM 64 bit */ #endif #ifndef ELF32_ST_VISIBILITY #define ELF32_ST_VISIBILITY(o) ((o) & 0x03) #endif /* For ELF64 the definitions are the same. */ #ifndef ELF64_ST_VISIBILITY #define ELF64_ST_VISIBILITY(o) ELF32_ST_VISIBILITY (o) #endif /* How to extract information held in the st_other field. */ #ifndef GELF_ST_VISIBILITY #define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val) #endif typedef Elf64_Nhdr GElf_Nhdr; #ifndef DMGL_PARAMS #define DMGL_NO_OPTS 0 /* For readability... */ #define DMGL_PARAMS (1 << 0) /* Include function args */ #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */ #endif #ifdef HAVE_LIBBFD_SUPPORT #define PACKAGE 'perf' #include #else #ifdef HAVE_CPLUS_DEMANGLE_SUPPORT extern char *cplus_demangle(const char *, int); static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i) { return cplus_demangle(c, i); } #else #ifdef NO_DEMANGLE static inline char *bfd_demangle(void __maybe_unused *v, const char __maybe_unused *c, int __maybe_unused i) { return NULL; } #endif #endif #endif #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT static int elf_getphdrnum(Elf *elf, size_t *dst) { GElf_Ehdr gehdr; GElf_Ehdr *ehdr; ehdr = gelf_getehdr(elf, &gehdr); if (!ehdr) return -1; *dst = ehdr->e_phnum; return 0; } #endif #ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused) { pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__); return -1; } #endif #ifndef NT_GNU_BUILD_ID #define NT_GNU_BUILD_ID 3 #endif /** * elf_symtab__for_each_symbol - iterate thru all the symbols * * @syms: struct elf_symtab instance to iterate * @idx: uint32_t idx * @sym: GElf_Sym iterator */ #define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \ for (idx = 0, gelf_getsym(syms, idx, &sym);\ idx < nr_syms; \ idx++, gelf_getsym(syms, idx, &sym)) static inline uint8_t elf_sym__type(const GElf_Sym *sym) { return GELF_ST_TYPE(sym->st_info); } static inline uint8_t elf_sym__visibility(const GElf_Sym *sym) { return GELF_ST_VISIBILITY(sym->st_other); } #ifndef STT_GNU_IFUNC #define STT_GNU_IFUNC 10 #endif static inline int elf_sym__is_function(const GElf_Sym *sym) { return (elf_sym__type(sym) == STT_FUNC || elf_sym__type(sym) == STT_GNU_IFUNC) && sym->st_name != 0 && sym->st_shndx != SHN_UNDEF; } static inline bool elf_sym__is_object(const GElf_Sym *sym) { return elf_sym__type(sym) == STT_OBJECT && sym->st_name != 0 && sym->st_shndx != SHN_UNDEF; } static inline int elf_sym__is_label(const GElf_Sym *sym) { return elf_sym__type(sym) == STT_NOTYPE && sym->st_name != 0 && sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS && elf_sym__visibility(sym) != STV_HIDDEN && elf_sym__visibility(sym) != STV_INTERNAL; } static bool elf_sym__filter(GElf_Sym *sym) { return elf_sym__is_function(sym) || elf_sym__is_object(sym); } static inline const char *elf_sym__name(const GElf_Sym *sym, const Elf_Data *symstrs) { return symstrs->d_buf + sym->st_name; } static inline const char *elf_sec__name(const GElf_Shdr *shdr, const Elf_Data *secstrs) { return secstrs->d_buf + shdr->sh_name; } static inline int elf_sec__is_text(const GElf_Shdr *shdr, const Elf_Data *secstrs) { return strstr(elf_sec__name(shdr, secstrs), "text") != NULL; } static inline bool elf_sec__is_data(const GElf_Shdr *shdr, const Elf_Data *secstrs) { return strstr(elf_sec__name(shdr, secstrs), "data") != NULL; } static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs) { return elf_sec__is_text(shdr, secstrs) || elf_sec__is_data(shdr, secstrs); } static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr) { Elf_Scn *sec = NULL; GElf_Shdr shdr; size_t cnt = 1; while ((sec = elf_nextscn(elf, sec)) != NULL) { gelf_getshdr(sec, &shdr); if ((addr >= shdr.sh_addr) && (addr < (shdr.sh_addr + shdr.sh_size))) return cnt; ++cnt; } return -1; } Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, GElf_Shdr *shp, const char *name, size_t *idx) { Elf_Scn *sec = NULL; size_t cnt = 1; /* Elf is corrupted/truncated, avoid calling elf_strptr. */ if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) return NULL; while ((sec = elf_nextscn(elf, sec)) != NULL) { char *str; gelf_getshdr(sec, shp); str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name); if (str && !strcmp(name, str)) { if (idx) *idx = cnt; return sec; } ++cnt; } return NULL; } static int elf_read_program_header(Elf *elf, u64 vaddr, GElf_Phdr *phdr) { size_t i, phdrnum; u64 sz; if (elf_getphdrnum(elf, &phdrnum)) return -1; for (i = 0; i < phdrnum; i++) { if (gelf_getphdr(elf, i, phdr) == NULL) return -1; if (phdr->p_type != PT_LOAD) continue; sz = max(phdr->p_memsz, phdr->p_filesz); if (!sz) continue; if (vaddr >= phdr->p_vaddr && (vaddr < phdr->p_vaddr + sz)) return 0; } /* Not found any valid program header */ return -1; } static bool want_demangle(bool is_kernel_sym) { return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle; } static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name) { int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS; char *demangled = NULL; /* * We need to figure out if the object was created from C++ sources * DWARF DW_compile_unit has this, but we don't always have access * to it... */ if (!want_demangle(dso->kernel || kmodule)) return demangled; demangled = bfd_demangle(NULL, elf_name, demangle_flags); if (demangled == NULL) { demangled = ocaml_demangle_sym(elf_name); if (demangled == NULL) { demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET); } } else if (rust_is_mangled(demangled)) /* * Input to Rust demangling is the BFD-demangled * name which it Rust-demangles in place. */ rust_demangle_sym(demangled); return demangled; } #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \ for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \ idx < nr_entries; \ ++idx, pos = gelf_getrel(reldata, idx, &pos_mem)) #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \ for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \ idx < nr_entries; \ ++idx, pos = gelf_getrela(reldata, idx, &pos_mem)) /* * We need to check if we have a .dynsym, so that we can handle the * .plt, synthesizing its symbols, that aren't on the symtabs (be it * .dynsym or .symtab). * And always look at the original dso, not at debuginfo packages, that * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS). */ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss) { uint32_t nr_rel_entries, idx; GElf_Sym sym; u64 plt_offset, plt_header_size, plt_entry_size; GElf_Shdr shdr_plt; struct symbol *f; GElf_Shdr shdr_rel_plt, shdr_dynsym; Elf_Data *reldata, *syms, *symstrs; Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym; size_t dynsym_idx; GElf_Ehdr ehdr; char sympltname[1024]; Elf *elf; int nr = 0, symidx, err = 0; if (!ss->dynsym) return 0; elf = ss->elf; ehdr = ss->ehdr; scn_dynsym = ss->dynsym; shdr_dynsym = ss->dynshdr; dynsym_idx = ss->dynsym_idx; if (scn_dynsym == NULL) goto out_elf_end; scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt, ".rela.plt", NULL); if (scn_plt_rel == NULL) { scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt, ".rel.plt", NULL); if (scn_plt_rel == NULL) goto out_elf_end; } err = -1; if (shdr_rel_plt.sh_link != dynsym_idx) goto out_elf_end; if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL) goto out_elf_end; /* * Fetch the relocation section to find the idxes to the GOT * and the symbols in the .dynsym they refer to. */ reldata = elf_getdata(scn_plt_rel, NULL); if (reldata == NULL) goto out_elf_end; syms = elf_getdata(scn_dynsym, NULL); if (syms == NULL) goto out_elf_end; scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link); if (scn_symstrs == NULL) goto out_elf_end; symstrs = elf_getdata(scn_symstrs, NULL); if (symstrs == NULL) goto out_elf_end; if (symstrs->d_size == 0) goto out_elf_end; nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize; plt_offset = shdr_plt.sh_offset; switch (ehdr.e_machine) { case EM_ARM: plt_header_size = 20; plt_entry_size = 12; break; case EM_AARCH64: plt_header_size = 32; plt_entry_size = 16; break; case EM_SPARC: plt_header_size = 48; plt_entry_size = 12; break; case EM_SPARCV9: plt_header_size = 128; plt_entry_size = 32; break; default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */ plt_header_size = shdr_plt.sh_entsize; plt_entry_size = shdr_plt.sh_entsize; break; } plt_offset += plt_header_size; if (shdr_rel_plt.sh_type == SHT_RELA) { GElf_Rela pos_mem, *pos; elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_rel_entries) { const char *elf_name = NULL; char *demangled = NULL; symidx = GELF_R_SYM(pos->r_info); gelf_getsym(syms, symidx, &sym); elf_name = elf_sym__name(&sym, symstrs); demangled = demangle_sym(dso, 0, elf_name); if (demangled != NULL) elf_name = demangled; snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_name); free(demangled); f = symbol__new(plt_offset, plt_entry_size, STB_GLOBAL, STT_FUNC, sympltname); if (!f) goto out_elf_end; plt_offset += plt_entry_size; symbols__insert(&dso->symbols, f); ++nr; } } else if (shdr_rel_plt.sh_type == SHT_REL) { GElf_Rel pos_mem, *pos; elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_rel_entries) { const char *elf_name = NULL; char *demangled = NULL; symidx = GELF_R_SYM(pos->r_info); gelf_getsym(syms, symidx, &sym); elf_name = elf_sym__name(&sym, symstrs); demangled = demangle_sym(dso, 0, elf_name); if (demangled != NULL) elf_name = demangled; snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_name); free(demangled); f = symbol__new(plt_offset, plt_entry_size, STB_GLOBAL, STT_FUNC, sympltname); if (!f) goto out_elf_end; plt_offset += plt_entry_size; symbols__insert(&dso->symbols, f); ++nr; } } err = 0; out_elf_end: if (err == 0) return nr; pr_debug("%s: problems reading %s PLT info.\n", __func__, dso->long_name); return 0; } char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name) { return demangle_sym(dso, kmodule, elf_name); } /* * Align offset to 4 bytes as needed for note name and descriptor data. */ #define NOTE_ALIGN(n) (((n) + 3) & -4U) static int elf_read_build_id(Elf *elf, void *bf, size_t size) { int err = -1; GElf_Ehdr ehdr; GElf_Shdr shdr; Elf_Data *data; Elf_Scn *sec; Elf_Kind ek; void *ptr; if (size < BUILD_ID_SIZE) goto out; ek = elf_kind(elf); if (ek != ELF_K_ELF) goto out; if (gelf_getehdr(elf, &ehdr) == NULL) { pr_err("%s: cannot get elf header.\n", __func__); goto out; } /* * Check following sections for notes: * '.note.gnu.build-id' * '.notes' * '.note' (VDSO specific) */ do { sec = elf_section_by_name(elf, &ehdr, &shdr, ".note.gnu.build-id", NULL); if (sec) break; sec = elf_section_by_name(elf, &ehdr, &shdr, ".notes", NULL); if (sec) break; sec = elf_section_by_name(elf, &ehdr, &shdr, ".note", NULL); if (sec) break; return err; } while (0); data = elf_getdata(sec, NULL); if (data == NULL) goto out; ptr = data->d_buf; while (ptr < (data->d_buf + data->d_size)) { GElf_Nhdr *nhdr = ptr; size_t namesz = NOTE_ALIGN(nhdr->n_namesz), descsz = NOTE_ALIGN(nhdr->n_descsz); const char *name; ptr += sizeof(*nhdr); name = ptr; ptr += namesz; if (nhdr->n_type == NT_GNU_BUILD_ID && nhdr->n_namesz == sizeof("GNU")) { if (memcmp(name, "GNU", sizeof("GNU")) == 0) { size_t sz = min(size, descsz); memcpy(bf, ptr, sz); memset(bf + sz, 0, size - sz); err = sz; break; } } ptr += descsz; } out: return err; } #ifdef HAVE_LIBBFD_BUILDID_SUPPORT static int read_build_id(const char *filename, struct build_id *bid) { size_t size = sizeof(bid->data); int err = -1; bfd *abfd; abfd = bfd_openr(filename, NULL); if (!abfd) return -1; if (!bfd_check_format(abfd, bfd_object)) { pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); goto out_close; } if (!abfd->build_id || abfd->build_id->size > size) goto out_close; memcpy(bid->data, abfd->build_id->data, abfd->build_id->size); memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size); err = bid->size = abfd->build_id->size; out_close: bfd_close(abfd); return err; } #else // HAVE_LIBBFD_BUILDID_SUPPORT static int read_build_id(const char *filename, struct build_id *bid) { size_t size = sizeof(bid->data); int fd, err = -1; Elf *elf; if (size < BUILD_ID_SIZE) goto out; fd = open(filename, O_RDONLY); if (fd < 0) goto out; elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (elf == NULL) { pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename); goto out_close; } err = elf_read_build_id(elf, bid->data, size); if (err > 0) bid->size = err; elf_end(elf); out_close: close(fd); out: return err; } #endif // HAVE_LIBBFD_BUILDID_SUPPORT int filename__read_build_id(const char *filename, struct build_id *bid) { struct kmod_path m = { .name = NULL, }; char path[PATH_MAX]; int err; if (!filename) return -EFAULT; err = kmod_path__parse(&m, filename); if (err) return -1; if (m.comp) { int error = 0, fd; fd = filename__decompress(filename, path, sizeof(path), m.comp, &error); if (fd < 0) { pr_debug("Failed to decompress (error %d) %s\n", error, filename); return -1; } close(fd); filename = path; } err = read_build_id(filename, bid); if (m.comp) unlink(filename); return err; } int sysfs__read_build_id(const char *filename, struct build_id *bid) { size_t size = sizeof(bid->data); int fd, err = -1; fd = open(filename, O_RDONLY); if (fd < 0) goto out; while (1) { char bf[BUFSIZ]; GElf_Nhdr nhdr; size_t namesz, descsz; if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr)) break; namesz = NOTE_ALIGN(nhdr.n_namesz); descsz = NOTE_ALIGN(nhdr.n_descsz); if (nhdr.n_type == NT_GNU_BUILD_ID && nhdr.n_namesz == sizeof("GNU")) { if (read(fd, bf, namesz) != (ssize_t)namesz) break; if (memcmp(bf, "GNU", sizeof("GNU")) == 0) { size_t sz = min(descsz, size); if (read(fd, bid->data, sz) == (ssize_t)sz) { memset(bid->data + sz, 0, size - sz); bid->size = sz; err = 0; break; } } else if (read(fd, bf, descsz) != (ssize_t)descsz) break; } else { int n = namesz + descsz; if (n > (int)sizeof(bf)) { n = sizeof(bf); pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n", __func__, filename, nhdr.n_namesz, nhdr.n_descsz); } if (read(fd, bf, n) != n) break; } } close(fd); out: return err; } #ifdef HAVE_LIBBFD_SUPPORT int filename__read_debuglink(const char *filename, char *debuglink, size_t size) { int err = -1; asection *section; bfd *abfd; abfd = bfd_openr(filename, NULL); if (!abfd) return -1; if (!bfd_check_format(abfd, bfd_object)) { pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename); goto out_close; } section = bfd_get_section_by_name(abfd, ".gnu_debuglink"); if (!section) goto out_close; if (section->size > size) goto out_close; if (!bfd_get_section_contents(abfd, section, debuglink, 0, section->size)) goto out_close; err = 0; out_close: bfd_close(abfd); return err; } #else int filename__read_debuglink(const char *filename, char *debuglink, size_t size) { int fd, err = -1; Elf *elf; GElf_Ehdr ehdr; GElf_Shdr shdr; Elf_Data *data; Elf_Scn *sec; Elf_Kind ek; fd = open(filename, O_RDONLY); if (fd < 0) goto out; elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (elf == NULL) { pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename); goto out_close; } ek = elf_kind(elf); if (ek != ELF_K_ELF) goto out_elf_end; if (gelf_getehdr(elf, &ehdr) == NULL) { pr_err("%s: cannot get elf header.\n", __func__); goto out_elf_end; } sec = elf_section_by_name(elf, &ehdr, &shdr, ".gnu_debuglink", NULL); if (sec == NULL) goto out_elf_end; data = elf_getdata(sec, NULL); if (data == NULL) goto out_elf_end; /* the start of this section is a zero-terminated string */ strncpy(debuglink, data->d_buf, size); err = 0; out_elf_end: elf_end(elf); out_close: close(fd); out: return err; } #endif static int dso__swap_init(struct dso *dso, unsigned char eidata) { static unsigned int const endian = 1; dso->needs_swap = DSO_SWAP__NO; switch (eidata) { case ELFDATA2LSB: /* We are big endian, DSO is little endian. */ if (*(unsigned char const *)&endian != 1) dso->needs_swap = DSO_SWAP__YES; break; case ELFDATA2MSB: /* We are little endian, DSO is big endian. */ if (*(unsigned char const *)&endian != 0) dso->needs_swap = DSO_SWAP__YES; break; default: pr_err("unrecognized DSO data encoding %d\n", eidata); return -EINVAL; } return 0; } bool symsrc__possibly_runtime(struct symsrc *ss) { return ss->dynsym || ss->opdsec; } bool symsrc__has_symtab(struct symsrc *ss) { return ss->symtab != NULL; } void symsrc__destroy(struct symsrc *ss) { zfree(&ss->name); elf_end(ss->elf); close(ss->fd); } bool elf__needs_adjust_symbols(GElf_Ehdr ehdr) { /* * Usually vmlinux is an ELF file with type ET_EXEC for most * architectures; except Arm64 kernel is linked with option * '-share', so need to check type ET_DYN. */ return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL || ehdr.e_type == ET_DYN; } int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, enum dso_binary_type type) { GElf_Ehdr ehdr; Elf *elf; int fd; if (dso__needs_decompress(dso)) { fd = dso__decompress_kmodule_fd(dso, name); if (fd < 0) return -1; type = dso->symtab_type; } else { fd = open(name, O_RDONLY); if (fd < 0) { dso->load_errno = errno; return -1; } } elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (elf == NULL) { pr_debug("%s: cannot read %s ELF file.\n", __func__, name); dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF; goto out_close; } if (gelf_getehdr(elf, &ehdr) == NULL) { dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF; pr_debug("%s: cannot get elf header.\n", __func__); goto out_elf_end; } if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) { dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR; goto out_elf_end; } /* Always reject images with a mismatched build-id: */ if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) { u8 build_id[BUILD_ID_SIZE]; struct build_id bid; int size; size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE); if (size <= 0) { dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID; goto out_elf_end; } build_id__init(&bid, build_id, size); if (!dso__build_id_equal(dso, &bid)) { pr_debug("%s: build id mismatch for %s.\n", __func__, name); dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID; goto out_elf_end; } } ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64); ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab", NULL); if (ss->symshdr.sh_type != SHT_SYMTAB) ss->symtab = NULL; ss->dynsym_idx = 0; ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym", &ss->dynsym_idx); if (ss->dynshdr.sh_type != SHT_DYNSYM) ss->dynsym = NULL; ss->opdidx = 0; ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd", &ss->opdidx); if (ss->opdshdr.sh_type != SHT_PROGBITS) ss->opdsec = NULL; if (dso->kernel == DSO_SPACE__USER) ss->adjust_symbols = true; else ss->adjust_symbols = elf__needs_adjust_symbols(ehdr); ss->name = strdup(name); if (!ss->name) { dso->load_errno = errno; goto out_elf_end; } ss->elf = elf; ss->fd = fd; ss->ehdr = ehdr; ss->type = type; return 0; out_elf_end: elf_end(elf); out_close: close(fd); return -1; } /** * ref_reloc_sym_not_found - has kernel relocation symbol been found. * @kmap: kernel maps and relocation reference symbol * * This function returns %true if we are dealing with the kernel maps and the * relocation reference symbol has not yet been found. Otherwise %false is * returned. */ static bool ref_reloc_sym_not_found(struct kmap *kmap) { return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name && !kmap->ref_reloc_sym->unrelocated_addr; } /** * ref_reloc - kernel relocation offset. * @kmap: kernel maps and relocation reference symbol * * This function returns the offset of kernel addresses as determined by using * the relocation reference symbol i.e. if the kernel has not been relocated * then the return value is zero. */ static u64 ref_reloc(struct kmap *kmap) { if (kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->unrelocated_addr) return kmap->ref_reloc_sym->addr - kmap->ref_reloc_sym->unrelocated_addr; return 0; } void __weak arch__sym_update(struct symbol *s __maybe_unused, GElf_Sym *sym __maybe_unused) { } static int dso__process_kernel_symbol(struct dso *dso, struct map *map, GElf_Sym *sym, GElf_Shdr *shdr, struct maps *kmaps, struct kmap *kmap, struct dso **curr_dsop, struct map **curr_mapp, const char *section_name, bool adjust_kernel_syms, bool kmodule, bool *remap_kernel) { struct dso *curr_dso = *curr_dsop; struct map *curr_map; char dso_name[PATH_MAX]; /* Adjust symbol to map to file offset */ if (adjust_kernel_syms) sym->st_value -= shdr->sh_addr - shdr->sh_offset; if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) == 0) return 0; if (strcmp(section_name, ".text") == 0) { /* * The initial kernel mapping is based on * kallsyms and identity maps. Overwrite it to * map to the kernel dso. */ if (*remap_kernel && dso->kernel && !kmodule) { *remap_kernel = false; map->start = shdr->sh_addr + ref_reloc(kmap); map->end = map->start + shdr->sh_size; map->pgoff = shdr->sh_offset; map->map_ip = map__map_ip; map->unmap_ip = map__unmap_ip; /* Ensure maps are correctly ordered */ if (kmaps) { map__get(map); maps__remove(kmaps, map); maps__insert(kmaps, map); map__put(map); } } /* * The initial module mapping is based on * /proc/modules mapped to offset zero. * Overwrite it to map to the module dso. */ if (*remap_kernel && kmodule) { *remap_kernel = false; map->pgoff = shdr->sh_offset; } *curr_mapp = map; *curr_dsop = dso; return 0; } if (!kmap) return 0; snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name); curr_map = maps__find_by_name(kmaps, dso_name); if (curr_map == NULL) { u64 start = sym->st_value; if (kmodule) start += map->start + shdr->sh_offset; curr_dso = dso__new(dso_name); if (curr_dso == NULL) return -1; curr_dso->kernel = dso->kernel; curr_dso->long_name = dso->long_name; curr_dso->long_name_len = dso->long_name_len; curr_map = map__new2(start, curr_dso); dso__put(curr_dso); if (curr_map == NULL) return -1; if (curr_dso->kernel) map__kmap(curr_map)->kmaps = kmaps; if (adjust_kernel_syms) { curr_map->start = shdr->sh_addr + ref_reloc(kmap); curr_map->end = curr_map->start + shdr->sh_size; curr_map->pgoff = shdr->sh_offset; } else { curr_map->map_ip = curr_map->unmap_ip = identity__map_ip; } curr_dso->symtab_type = dso->symtab_type; maps__insert(kmaps, curr_map); /* * Add it before we drop the reference to curr_map, i.e. while * we still are sure to have a reference to this DSO via * *curr_map->dso. */ dsos__add(&kmaps->machine->dsos, curr_dso); /* kmaps already got it */ map__put(curr_map); dso__set_loaded(curr_dso); *curr_mapp = curr_map; *curr_dsop = curr_dso; } else *curr_dsop = curr_map->dso; return 0; } static int dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss, struct symsrc *runtime_ss, int kmodule, int dynsym) { struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL; struct maps *kmaps = kmap ? map__kmaps(map) : NULL; struct map *curr_map = map; struct dso *curr_dso = dso; Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym; uint32_t nr_syms; int err = -1; uint32_t idx; GElf_Ehdr ehdr; GElf_Shdr shdr; GElf_Shdr tshdr; Elf_Data *syms, *opddata = NULL; GElf_Sym sym; Elf_Scn *sec, *sec_strndx; Elf *elf; int nr = 0; bool remap_kernel = false, adjust_kernel_syms = false; if (kmap && !kmaps) return -1; elf = syms_ss->elf; ehdr = syms_ss->ehdr; if (dynsym) { sec = syms_ss->dynsym; shdr = syms_ss->dynshdr; } else { sec = syms_ss->symtab; shdr = syms_ss->symshdr; } if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr, ".text", NULL)) dso->text_offset = tshdr.sh_addr - tshdr.sh_offset; if (runtime_ss->opdsec) opddata = elf_rawdata(runtime_ss->opdsec, NULL); syms = elf_getdata(sec, NULL); if (syms == NULL) goto out_elf_end; sec = elf_getscn(elf, shdr.sh_link); if (sec == NULL) goto out_elf_end; symstrs = elf_getdata(sec, NULL); if (symstrs == NULL) goto out_elf_end; sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx); if (sec_strndx == NULL) goto out_elf_end; secstrs_run = elf_getdata(sec_strndx, NULL); if (secstrs_run == NULL) goto out_elf_end; sec_strndx = elf_getscn(elf, ehdr.e_shstrndx); if (sec_strndx == NULL) goto out_elf_end; secstrs_sym = elf_getdata(sec_strndx, NULL); if (secstrs_sym == NULL) goto out_elf_end; nr_syms = shdr.sh_size / shdr.sh_entsize; memset(&sym, 0, sizeof(sym)); /* * The kernel relocation symbol is needed in advance in order to adjust * kernel maps correctly. */ if (ref_reloc_sym_not_found(kmap)) { elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { const char *elf_name = elf_sym__name(&sym, symstrs); if (strcmp(elf_name, kmap->ref_reloc_sym->name)) continue; kmap->ref_reloc_sym->unrelocated_addr = sym.st_value; map->reloc = kmap->ref_reloc_sym->addr - kmap->ref_reloc_sym->unrelocated_addr; break; } } /* * Handle any relocation of vdso necessary because older kernels * attempted to prelink vdso to its virtual address. */ if (dso__is_vdso(dso)) map->reloc = map->start - dso->text_offset; dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap); /* * Initial kernel and module mappings do not map to the dso. * Flag the fixups. */ if (dso->kernel) { remap_kernel = true; adjust_kernel_syms = dso->adjust_symbols; } elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { struct symbol *f; const char *elf_name = elf_sym__name(&sym, symstrs); char *demangled = NULL; int is_label = elf_sym__is_label(&sym); const char *section_name; bool used_opd = false; if (!is_label && !elf_sym__filter(&sym)) continue; /* Reject ARM ELF "mapping symbols": these aren't unique and * don't identify functions, so will confuse the profile * output: */ if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) { if (elf_name[0] == '$' && strchr("adtx", elf_name[1]) && (elf_name[2] == '\0' || elf_name[2] == '.')) continue; } if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) { u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr; u64 *opd = opddata->d_buf + offset; sym.st_value = DSO__SWAP(dso, u64, *opd); sym.st_shndx = elf_addr_to_index(runtime_ss->elf, sym.st_value); used_opd = true; } /* * When loading symbols in a data mapping, ABS symbols (which * has a value of SHN_ABS in its st_shndx) failed at * elf_getscn(). And it marks the loading as a failure so * already loaded symbols cannot be fixed up. * * I'm not sure what should be done. Just ignore them for now. * - Namhyung Kim */ if (sym.st_shndx == SHN_ABS) continue; sec = elf_getscn(syms_ss->elf, sym.st_shndx); if (!sec) goto out_elf_end; gelf_getshdr(sec, &shdr); secstrs = secstrs_sym; /* * We have to fallback to runtime when syms' section header has * NOBITS set. NOBITS results in file offset (sh_offset) not * being incremented. So sh_offset used below has different * values for syms (invalid) and runtime (valid). */ if (shdr.sh_type == SHT_NOBITS) { sec = elf_getscn(runtime_ss->elf, sym.st_shndx); if (!sec) goto out_elf_end; gelf_getshdr(sec, &shdr); secstrs = secstrs_run; } if (is_label && !elf_sec__filter(&shdr, secstrs)) continue; section_name = elf_sec__name(&shdr, secstrs); /* On ARM, symbols for thumb functions have 1 added to * the symbol address as a flag - remove it */ if ((ehdr.e_machine == EM_ARM) && (GELF_ST_TYPE(sym.st_info) == STT_FUNC) && (sym.st_value & 1)) --sym.st_value; if (dso->kernel) { if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map, section_name, adjust_kernel_syms, kmodule, &remap_kernel)) goto out_elf_end; } else if ((used_opd && runtime_ss->adjust_symbols) || (!used_opd && syms_ss->adjust_symbols)) { GElf_Phdr phdr; if (elf_read_program_header(runtime_ss->elf, (u64)sym.st_value, &phdr)) { pr_debug4("%s: failed to find program header for " "symbol: %s st_value: %#" PRIx64 "\n", __func__, elf_name, (u64)sym.st_value); pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " " "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__, (u64)sym.st_value, (u64)shdr.sh_addr, (u64)shdr.sh_offset); /* * Fail to find program header, let's rollback * to use shdr.sh_addr and shdr.sh_offset to * calibrate symbol's file address, though this * is not necessary for normal C ELF file, we * still need to handle java JIT symbols in this * case. */ sym.st_value -= shdr.sh_addr - shdr.sh_offset; } else { pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " " "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n", __func__, (u64)sym.st_value, (u64)phdr.p_vaddr, (u64)phdr.p_offset); sym.st_value -= phdr.p_vaddr - phdr.p_offset; } } demangled = demangle_sym(dso, kmodule, elf_name); if (demangled != NULL) elf_name = demangled; f = symbol__new(sym.st_value, sym.st_size, GELF_ST_BIND(sym.st_info), GELF_ST_TYPE(sym.st_info), elf_name); free(demangled); if (!f) goto out_elf_end; arch__sym_update(f, &sym); __symbols__insert(&curr_dso->symbols, f, dso->kernel); nr++; } /* * For misannotated, zeroed, ASM function sizes. */ if (nr > 0) { symbols__fixup_end(&dso->symbols, false); symbols__fixup_duplicate(&dso->symbols); if (kmap) { /* * We need to fixup this here too because we create new * maps here, for things like vsyscall sections. */ maps__fixup_end(kmaps); } } err = nr; out_elf_end: return err; } int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss, struct symsrc *runtime_ss, int kmodule) { int nr = 0; int err = -1; dso->symtab_type = syms_ss->type; dso->is_64_bit = syms_ss->is_64_bit; dso->rel = syms_ss->ehdr.e_type == ET_REL; /* * Modules may already have symbols from kallsyms, but those symbols * have the wrong values for the dso maps, so remove them. */ if (kmodule && syms_ss->symtab) symbols__delete(&dso->symbols); if (!syms_ss->symtab) { /* * If the vmlinux is stripped, fail so we will fall back * to using kallsyms. The vmlinux runtime symbols aren't * of much use. */ if (dso->kernel) return err; } else { err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss, kmodule, 0); if (err < 0) return err; nr = err; } if (syms_ss->dynsym) { err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss, kmodule, 1); if (err < 0) return err; err += nr; } return err; } static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data) { GElf_Phdr phdr; size_t i, phdrnum; int err; u64 sz; if (elf_getphdrnum(elf, &phdrnum)) return -1; for (i = 0; i < phdrnum; i++) { if (gelf_getphdr(elf, i, &phdr) == NULL) return -1; if (phdr.p_type != PT_LOAD) continue; if (exe) { if (!(phdr.p_flags & PF_X)) continue; } else { if (!(phdr.p_flags & PF_R)) continue; } sz = min(phdr.p_memsz, phdr.p_filesz); if (!sz) continue; err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data); if (err) return err; } return 0; } int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data, bool *is_64_bit) { int err; Elf *elf; elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (elf == NULL) return -1; if (is_64_bit) *is_64_bit = (gelf_getclass(elf) == ELFCLASS64); err = elf_read_maps(elf, exe, mapfn, data); elf_end(elf); return err; } enum dso_type dso__type_fd(int fd) { enum dso_type dso_type = DSO__TYPE_UNKNOWN; GElf_Ehdr ehdr; Elf_Kind ek; Elf *elf; elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (elf == NULL) goto out; ek = elf_kind(elf); if (ek != ELF_K_ELF) goto out_end; if (gelf_getclass(elf) == ELFCLASS64) { dso_type = DSO__TYPE_64BIT; goto out_end; } if (gelf_getehdr(elf, &ehdr) == NULL) goto out_end; if (ehdr.e_machine == EM_X86_64) dso_type = DSO__TYPE_X32BIT; else dso_type = DSO__TYPE_32BIT; out_end: elf_end(elf); out: return dso_type; } static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len) { ssize_t r; size_t n; int err = -1; char *buf = malloc(page_size); if (buf == NULL) return -1; if (lseek(to, to_offs, SEEK_SET) != to_offs) goto out; if (lseek(from, from_offs, SEEK_SET) != from_offs) goto out; while (len) { n = page_size; if (len < n) n = len; /* Use read because mmap won't work on proc files */ r = read(from, buf, n); if (r < 0) goto out; if (!r) break; n = r; r = write(to, buf, n); if (r < 0) goto out; if ((size_t)r != n) goto out; len -= n; } err = 0; out: free(buf); return err; } struct kcore { int fd; int elfclass; Elf *elf; GElf_Ehdr ehdr; }; static int kcore__open(struct kcore *kcore, const char *filename) { GElf_Ehdr *ehdr; kcore->fd = open(filename, O_RDONLY); if (kcore->fd == -1) return -1; kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL); if (!kcore->elf) goto out_close; kcore->elfclass = gelf_getclass(kcore->elf); if (kcore->elfclass == ELFCLASSNONE) goto out_end; ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr); if (!ehdr) goto out_end; return 0; out_end: elf_end(kcore->elf); out_close: close(kcore->fd); return -1; } static int kcore__init(struct kcore *kcore, char *filename, int elfclass, bool temp) { kcore->elfclass = elfclass; if (temp) kcore->fd = mkstemp(filename); else kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400); if (kcore->fd == -1) return -1; kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL); if (!kcore->elf) goto out_close; if (!gelf_newehdr(kcore->elf, elfclass)) goto out_end; memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr)); return 0; out_end: elf_end(kcore->elf); out_close: close(kcore->fd); unlink(filename); return -1; } static void kcore__close(struct kcore *kcore) { elf_end(kcore->elf); close(kcore->fd); } static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count) { GElf_Ehdr *ehdr = &to->ehdr; GElf_Ehdr *kehdr = &from->ehdr; memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT); ehdr->e_type = kehdr->e_type; ehdr->e_machine = kehdr->e_machine; ehdr->e_version = kehdr->e_version; ehdr->e_entry = 0; ehdr->e_shoff = 0; ehdr->e_flags = kehdr->e_flags; ehdr->e_phnum = count; ehdr->e_shentsize = 0; ehdr->e_shnum = 0; ehdr->e_shstrndx = 0; if (from->elfclass == ELFCLASS32) { ehdr->e_phoff = sizeof(Elf32_Ehdr); ehdr->e_ehsize = sizeof(Elf32_Ehdr); ehdr->e_phentsize = sizeof(Elf32_Phdr); } else { ehdr->e_phoff = sizeof(Elf64_Ehdr); ehdr->e_ehsize = sizeof(Elf64_Ehdr); ehdr->e_phentsize = sizeof(Elf64_Phdr); } if (!gelf_update_ehdr(to->elf, ehdr)) return -1; if (!gelf_newphdr(to->elf, count)) return -1; return 0; } static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset, u64 addr, u64 len) { GElf_Phdr phdr = { .p_type = PT_LOAD, .p_flags = PF_R | PF_W | PF_X, .p_offset = offset, .p_vaddr = addr, .p_paddr = 0, .p_filesz = len, .p_memsz = len, .p_align = page_size, }; if (!gelf_update_phdr(kcore->elf, idx, &phdr)) return -1; return 0; } static off_t kcore__write(struct kcore *kcore) { return elf_update(kcore->elf, ELF_C_WRITE); } struct phdr_data { off_t offset; off_t rel; u64 addr; u64 len; struct list_head node; struct phdr_data *remaps; }; struct sym_data { u64 addr; struct list_head node; }; struct kcore_copy_info { u64 stext; u64 etext; u64 first_symbol; u64 last_symbol; u64 first_module; u64 first_module_symbol; u64 last_module_symbol; size_t phnum; struct list_head phdrs; struct list_head syms; }; #define kcore_copy__for_each_phdr(k, p) \ list_for_each_entry((p), &(k)->phdrs, node) static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset) { struct phdr_data *p = zalloc(sizeof(*p)); if (p) { p->addr = addr; p->len = len; p->offset = offset; } return p; } static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci, u64 addr, u64 len, off_t offset) { struct phdr_data *p = phdr_data__new(addr, len, offset); if (p) list_add_tail(&p->node, &kci->phdrs); return p; } static void kcore_copy__free_phdrs(struct kcore_copy_info *kci) { struct phdr_data *p, *tmp; list_for_each_entry_safe(p, tmp, &kci->phdrs, node) { list_del_init(&p->node); free(p); } } static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci, u64 addr) { struct sym_data *s = zalloc(sizeof(*s)); if (s) { s->addr = addr; list_add_tail(&s->node, &kci->syms); } return s; } static void kcore_copy__free_syms(struct kcore_copy_info *kci) { struct sym_data *s, *tmp; list_for_each_entry_safe(s, tmp, &kci->syms, node) { list_del_init(&s->node); free(s); } } static int kcore_copy__process_kallsyms(void *arg, const char *name, char type, u64 start) { struct kcore_copy_info *kci = arg; if (!kallsyms__is_function(type)) return 0; if (strchr(name, '[')) { if (!kci->first_module_symbol || start < kci->first_module_symbol) kci->first_module_symbol = start; if (start > kci->last_module_symbol) kci->last_module_symbol = start; return 0; } if (!kci->first_symbol || start < kci->first_symbol) kci->first_symbol = start; if (!kci->last_symbol || start > kci->last_symbol) kci->last_symbol = start; if (!strcmp(name, "_stext")) { kci->stext = start; return 0; } if (!strcmp(name, "_etext")) { kci->etext = start; return 0; } if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start)) return -1; return 0; } static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci, const char *dir) { char kallsyms_filename[PATH_MAX]; scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir); if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms")) return -1; if (kallsyms__parse(kallsyms_filename, kci, kcore_copy__process_kallsyms) < 0) return -1; return 0; } static int kcore_copy__process_modules(void *arg, const char *name __maybe_unused, u64 start, u64 size __maybe_unused) { struct kcore_copy_info *kci = arg; if (!kci->first_module || start < kci->first_module) kci->first_module = start; return 0; } static int kcore_copy__parse_modules(struct kcore_copy_info *kci, const char *dir) { char modules_filename[PATH_MAX]; scnprintf(modules_filename, PATH_MAX, "%s/modules", dir); if (symbol__restricted_filename(modules_filename, "/proc/modules")) return -1; if (modules__parse(modules_filename, kci, kcore_copy__process_modules) < 0) return -1; return 0; } static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end, u64 pgoff, u64 s, u64 e) { u64 len, offset; if (s < start || s >= end) return 0; offset = (s - start) + pgoff; len = e < end ? e - s : end - s; return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1; } static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data) { struct kcore_copy_info *kci = data; u64 end = start + len; struct sym_data *sdat; if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext)) return -1; if (kcore_copy__map(kci, start, end, pgoff, kci->first_module, kci->last_module_symbol)) return -1; list_for_each_entry(sdat, &kci->syms, node) { u64 s = round_down(sdat->addr, page_size); if (kcore_copy__map(kci, start, end, pgoff, s, s + len)) return -1; } return 0; } static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf) { if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0) return -1; return 0; } static void kcore_copy__find_remaps(struct kcore_copy_info *kci) { struct phdr_data *p, *k = NULL; u64 kend; if (!kci->stext) return; /* Find phdr that corresponds to the kernel map (contains stext) */ kcore_copy__for_each_phdr(kci, p) { u64 pend = p->addr + p->len - 1; if (p->addr <= kci->stext && pend >= kci->stext) { k = p; break; } } if (!k) return; kend = k->offset + k->len; /* Find phdrs that remap the kernel */ kcore_copy__for_each_phdr(kci, p) { u64 pend = p->offset + p->len; if (p == k) continue; if (p->offset >= k->offset && pend <= kend) p->remaps = k; } } static void kcore_copy__layout(struct kcore_copy_info *kci) { struct phdr_data *p; off_t rel = 0; kcore_copy__find_remaps(kci); kcore_copy__for_each_phdr(kci, p) { if (!p->remaps) { p->rel = rel; rel += p->len; } kci->phnum += 1; } kcore_copy__for_each_phdr(kci, p) { struct phdr_data *k = p->remaps; if (k) p->rel = p->offset - k->offset + k->rel; } } static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir, Elf *elf) { if (kcore_copy__parse_kallsyms(kci, dir)) return -1; if (kcore_copy__parse_modules(kci, dir)) return -1; if (kci->stext) kci->stext = round_down(kci->stext, page_size); else kci->stext = round_down(kci->first_symbol, page_size); if (kci->etext) { kci->etext = round_up(kci->etext, page_size); } else if (kci->last_symbol) { kci->etext = round_up(kci->last_symbol, page_size); kci->etext += page_size; } if (kci->first_module_symbol && (!kci->first_module || kci->first_module_symbol < kci->first_module)) kci->first_module = kci->first_module_symbol; kci->first_module = round_down(kci->first_module, page_size); if (kci->last_module_symbol) { kci->last_module_symbol = round_up(kci->last_module_symbol, page_size); kci->last_module_symbol += page_size; } if (!kci->stext || !kci->etext) return -1; if (kci->first_module && !kci->last_module_symbol) return -1; if (kcore_copy__read_maps(kci, elf)) return -1; kcore_copy__layout(kci); return 0; } static int kcore_copy__copy_file(const char *from_dir, const char *to_dir, const char *name) { char from_filename[PATH_MAX]; char to_filename[PATH_MAX]; scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); return copyfile_mode(from_filename, to_filename, 0400); } static int kcore_copy__unlink(const char *dir, const char *name) { char filename[PATH_MAX]; scnprintf(filename, PATH_MAX, "%s/%s", dir, name); return unlink(filename); } static int kcore_copy__compare_fds(int from, int to) { char *buf_from; char *buf_to; ssize_t ret; size_t len; int err = -1; buf_from = malloc(page_size); buf_to = malloc(page_size); if (!buf_from || !buf_to) goto out; while (1) { /* Use read because mmap won't work on proc files */ ret = read(from, buf_from, page_size); if (ret < 0) goto out; if (!ret) break; len = ret; if (readn(to, buf_to, len) != (int)len) goto out; if (memcmp(buf_from, buf_to, len)) goto out; } err = 0; out: free(buf_to); free(buf_from); return err; } static int kcore_copy__compare_files(const char *from_filename, const char *to_filename) { int from, to, err = -1; from = open(from_filename, O_RDONLY); if (from < 0) return -1; to = open(to_filename, O_RDONLY); if (to < 0) goto out_close_from; err = kcore_copy__compare_fds(from, to); close(to); out_close_from: close(from); return err; } static int kcore_copy__compare_file(const char *from_dir, const char *to_dir, const char *name) { char from_filename[PATH_MAX]; char to_filename[PATH_MAX]; scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name); scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name); return kcore_copy__compare_files(from_filename, to_filename); } /** * kcore_copy - copy kallsyms, modules and kcore from one directory to another. * @from_dir: from directory * @to_dir: to directory * * This function copies kallsyms, modules and kcore files from one directory to * another. kallsyms and modules are copied entirely. Only code segments are * copied from kcore. It is assumed that two segments suffice: one for the * kernel proper and one for all the modules. The code segments are determined * from kallsyms and modules files. The kernel map starts at _stext or the * lowest function symbol, and ends at _etext or the highest function symbol. * The module map starts at the lowest module address and ends at the highest * module symbol. Start addresses are rounded down to the nearest page. End * addresses are rounded up to the nearest page. An extra page is added to the * highest kernel symbol and highest module symbol to, hopefully, encompass that * symbol too. Because it contains only code sections, the resulting kcore is * unusual. One significant peculiarity is that the mapping (start -> pgoff) * is not the same for the kernel map and the modules map. That happens because * the data is copied adjacently whereas the original kcore has gaps. Finally, * kallsyms file is compared with its copy to check that modules have not been * loaded or unloaded while the copies were taking place. * * Return: %0 on success, %-1 on failure. */ int kcore_copy(const char *from_dir, const char *to_dir) { struct kcore kcore; struct kcore extract; int idx = 0, err = -1; off_t offset, sz; struct kcore_copy_info kci = { .stext = 0, }; char kcore_filename[PATH_MAX]; char extract_filename[PATH_MAX]; struct phdr_data *p; INIT_LIST_HEAD(&kci.phdrs); INIT_LIST_HEAD(&kci.syms); if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms")) return -1; if (kcore_copy__copy_file(from_dir, to_dir, "modules")) goto out_unlink_kallsyms; scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir); scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir); if (kcore__open(&kcore, kcore_filename)) goto out_unlink_modules; if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf)) goto out_kcore_close; if (kcore__init(&extract, extract_filename, kcore.elfclass, false)) goto out_kcore_close; if (kcore__copy_hdr(&kcore, &extract, kci.phnum)) goto out_extract_close; offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) + gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT); offset = round_up(offset, page_size); kcore_copy__for_each_phdr(&kci, p) { off_t offs = p->rel + offset; if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len)) goto out_extract_close; } sz = kcore__write(&extract); if (sz < 0 || sz > offset) goto out_extract_close; kcore_copy__for_each_phdr(&kci, p) { off_t offs = p->rel + offset; if (p->remaps) continue; if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len)) goto out_extract_close; } if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms")) goto out_extract_close; err = 0; out_extract_close: kcore__close(&extract); if (err) unlink(extract_filename); out_kcore_close: kcore__close(&kcore); out_unlink_modules: if (err) kcore_copy__unlink(to_dir, "modules"); out_unlink_kallsyms: if (err) kcore_copy__unlink(to_dir, "kallsyms"); kcore_copy__free_phdrs(&kci); kcore_copy__free_syms(&kci); return err; } int kcore_extract__create(struct kcore_extract *kce) { struct kcore kcore; struct kcore extract; size_t count = 1; int idx = 0, err = -1; off_t offset = page_size, sz; if (kcore__open(&kcore, kce->kcore_filename)) return -1; strcpy(kce->extract_filename, PERF_KCORE_EXTRACT); if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true)) goto out_kcore_close; if (kcore__copy_hdr(&kcore, &extract, count)) goto out_extract_close; if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len)) goto out_extract_close; sz = kcore__write(&extract); if (sz < 0 || sz > offset) goto out_extract_close; if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len)) goto out_extract_close; err = 0; out_extract_close: kcore__close(&extract); if (err) unlink(kce->extract_filename); out_kcore_close: kcore__close(&kcore); return err; } void kcore_extract__delete(struct kcore_extract *kce) { unlink(kce->extract_filename); } #ifdef HAVE_GELF_GETNOTE_SUPPORT static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off) { if (!base_off) return; if (tmp->bit32) tmp->addr.a32[SDT_NOTE_IDX_LOC] = tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off - tmp->addr.a32[SDT_NOTE_IDX_BASE]; else tmp->addr.a64[SDT_NOTE_IDX_LOC] = tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off - tmp->addr.a64[SDT_NOTE_IDX_BASE]; } static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr, GElf_Addr base_off) { if (!base_off) return; if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR]) tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off); else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR]) tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off); } /** * populate_sdt_note : Parse raw data and identify SDT note * @elf: elf of the opened file * @data: raw data of a section with description offset applied * @len: note description size * @type: type of the note * @sdt_notes: List to add the SDT note * * Responsible for parsing the @data in section .note.stapsdt in @elf and * if its an SDT note, it appends to @sdt_notes list. */ static int populate_sdt_note(Elf **elf, const char *data, size_t len, struct list_head *sdt_notes) { const char *provider, *name, *args; struct sdt_note *tmp = NULL; GElf_Ehdr ehdr; GElf_Shdr shdr; int ret = -EINVAL; union { Elf64_Addr a64[NR_ADDR]; Elf32_Addr a32[NR_ADDR]; } buf; Elf_Data dst = { .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT, .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT), .d_off = 0, .d_align = 0 }; Elf_Data src = { .d_buf = (void *) data, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0, .d_align = 0 }; tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note)); if (!tmp) { ret = -ENOMEM; goto out_err; } INIT_LIST_HEAD(&tmp->note_list); if (len < dst.d_size + 3) goto out_free_note; /* Translation from file representation to memory representation */ if (gelf_xlatetom(*elf, &dst, &src, elf_getident(*elf, NULL)[EI_DATA]) == NULL) { pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1)); goto out_free_note; } /* Populate the fields of sdt_note */ provider = data + dst.d_size; name = (const char *)memchr(provider, '\0', data + len - provider); if (name++ == NULL) goto out_free_note; tmp->provider = strdup(provider); if (!tmp->provider) { ret = -ENOMEM; goto out_free_note; } tmp->name = strdup(name); if (!tmp->name) { ret = -ENOMEM; goto out_free_prov; } args = memchr(name, '\0', data + len - name); /* * There is no argument if: * - We reached the end of the note; * - There is not enough room to hold a potential string; * - The argument string is empty or just contains ':'. */ if (args == NULL || data + len - args < 2 || args[1] == ':' || args[1] == '\0') tmp->args = NULL; else { tmp->args = strdup(++args); if (!tmp->args) { ret = -ENOMEM; goto out_free_name; } } if (gelf_getclass(*elf) == ELFCLASS32) { memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr)); tmp->bit32 = true; } else { memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr)); tmp->bit32 = false; } if (!gelf_getehdr(*elf, &ehdr)) { pr_debug("%s : cannot get elf header.\n", __func__); ret = -EBADF; goto out_free_args; } /* Adjust the prelink effect : * Find out the .stapsdt.base section. * This scn will help us to handle prelinking (if present). * Compare the retrieved file offset of the base section with the * base address in the description of the SDT note. If its different, * then accordingly, adjust the note location. */ if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) sdt_adjust_loc(tmp, shdr.sh_offset); /* Adjust reference counter offset */ if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL)) sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset); list_add_tail(&tmp->note_list, sdt_notes); return 0; out_free_args: zfree(&tmp->args); out_free_name: zfree(&tmp->name); out_free_prov: zfree(&tmp->provider); out_free_note: free(tmp); out_err: return ret; } /** * construct_sdt_notes_list : constructs a list of SDT notes * @elf : elf to look into * @sdt_notes : empty list_head * * Scans the sections in 'elf' for the section * .note.stapsdt. It, then calls populate_sdt_note to find * out the SDT events and populates the 'sdt_notes'. */ static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes) { GElf_Ehdr ehdr; Elf_Scn *scn = NULL; Elf_Data *data; GElf_Shdr shdr; size_t shstrndx, next; GElf_Nhdr nhdr; size_t name_off, desc_off, offset; int ret = 0; if (gelf_getehdr(elf, &ehdr) == NULL) { ret = -EBADF; goto out_ret; } if (elf_getshdrstrndx(elf, &shstrndx) != 0) { ret = -EBADF; goto out_ret; } /* Look for the required section */ scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL); if (!scn) { ret = -ENOENT; goto out_ret; } if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) { ret = -ENOENT; goto out_ret; } data = elf_getdata(scn, NULL); /* Get the SDT notes */ for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off, &desc_off)) > 0; offset = next) { if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) && !memcmp(data->d_buf + name_off, SDT_NOTE_NAME, sizeof(SDT_NOTE_NAME))) { /* Check the type of the note */ if (nhdr.n_type != SDT_NOTE_TYPE) goto out_ret; ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off), nhdr.n_descsz, sdt_notes); if (ret < 0) goto out_ret; } } if (list_empty(sdt_notes)) ret = -ENOENT; out_ret: return ret; } /** * get_sdt_note_list : Wrapper to construct a list of sdt notes * @head : empty list_head * @target : file to find SDT notes from * * This opens the file, initializes * the ELF and then calls construct_sdt_notes_list. */ int get_sdt_note_list(struct list_head *head, const char *target) { Elf *elf; int fd, ret; fd = open(target, O_RDONLY); if (fd < 0) return -EBADF; elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (!elf) { ret = -EBADF; goto out_close; } ret = construct_sdt_notes_list(elf, head); elf_end(elf); out_close: close(fd); return ret; } /** * cleanup_sdt_note_list : free the sdt notes' list * @sdt_notes: sdt notes' list * * Free up the SDT notes in @sdt_notes. * Returns the number of SDT notes free'd. */ int cleanup_sdt_note_list(struct list_head *sdt_notes) { struct sdt_note *tmp, *pos; int nr_free = 0; list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) { list_del_init(&pos->note_list); zfree(&pos->args); zfree(&pos->name); zfree(&pos->provider); free(pos); nr_free++; } return nr_free; } /** * sdt_notes__get_count: Counts the number of sdt events * @start: list_head to sdt_notes list * * Returns the number of SDT notes in a list */ int sdt_notes__get_count(struct list_head *start) { struct sdt_note *sdt_ptr; int count = 0; list_for_each_entry(sdt_ptr, start, note_list) count++; return count; } #endif void symbol__elf_init(void) { elf_version(EV_CURRENT); }