diff options
Diffstat (limited to 'tools/perf/util/symbol-elf.c')
| -rw-r--r-- | tools/perf/util/symbol-elf.c | 2624 |
1 files changed, 2353 insertions, 271 deletions
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 4b12bf850325..957143fbf8a0 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -1,12 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0 #include <fcntl.h> #include <stdio.h> #include <errno.h> +#include <stdlib.h> #include <string.h> #include <unistd.h> #include <inttypes.h> +#include "compress.h" +#include "dso.h" +#include "libbfd.h" +#include "map.h" +#include "maps.h" #include "symbol.h" +#include "symsrc.h" +#include "machine.h" +#include "vdso.h" #include "debug.h" +#include "util/copyfile.h" +#include <linux/ctype.h> +#include <linux/kernel.h> +#include <linux/zalloc.h> +#include <linux/string.h> +#include <symbol/kallsyms.h> +#include <internal/lib.h> + +#ifndef EM_AARCH64 +#define EM_AARCH64 183 /* ARM 64 bit */ +#endif + +#ifndef EM_LOONGARCH +#define EM_LOONGARCH 258 +#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 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 @@ -29,9 +95,19 @@ 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 && + return (elf_sym__type(sym) == STT_FUNC || + elf_sym__type(sym) == STT_GNU_IFUNC) && sym->st_name != 0 && sym->st_shndx != SHN_UNDEF; } @@ -48,19 +124,14 @@ 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; + sym->st_shndx != SHN_ABS && + elf_sym__visibility(sym) != STV_HIDDEN && + elf_sym__visibility(sym) != STV_INTERNAL; } -static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type) +static bool elf_sym__filter(GElf_Sym *sym) { - switch (type) { - case MAP__FUNCTION: - return elf_sym__is_function(sym); - case MAP__VARIABLE: - return elf_sym__is_object(sym); - default: - return false; - } + return elf_sym__is_function(sym) || elf_sym__is_object(sym); } static inline const char *elf_sym__name(const GElf_Sym *sym, @@ -87,17 +158,10 @@ static inline bool elf_sec__is_data(const GElf_Shdr *shdr, return strstr(elf_sec__name(shdr, secstrs), "data") != NULL; } -static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs, - enum map_type type) +static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs) { - switch (type) { - case MAP__FUNCTION: - return elf_sec__is_text(shdr, secstrs); - case MAP__VARIABLE: - return elf_sec__is_data(shdr, secstrs); - default: - return false; - } + 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) @@ -119,14 +183,13 @@ static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr) return -1; } -static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, - GElf_Shdr *shp, const char *name, - size_t *idx) +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. */ + /* ELF is corrupted/truncated, avoid calling elf_strptr. */ if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) return NULL; @@ -135,26 +198,401 @@ static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, gelf_getshdr(sec, shp); str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name); - if (!strcmp(name, str)) { + if (str && !strcmp(name, str)) { if (idx) *idx = cnt; - break; + return sec; } ++cnt; } - return sec; + return NULL; } -#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)) +bool filename__has_section(const char *filename, const char *sec) +{ + int fd; + Elf *elf; + GElf_Ehdr ehdr; + GElf_Shdr shdr; + bool found = false; -#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)) + fd = open(filename, O_RDONLY); + if (fd < 0) + return false; + + elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); + if (elf == NULL) + goto out; + + if (gelf_getehdr(elf, &ehdr) == NULL) + goto elf_out; + + found = !!elf_section_by_name(elf, &ehdr, &shdr, sec, NULL); + +elf_out: + elf_end(elf); +out: + close(fd); + return found; +} + +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; +} + +struct rel_info { + u32 nr_entries; + u32 *sorted; + bool is_rela; + Elf_Data *reldata; + GElf_Rela rela; + GElf_Rel rel; +}; + +static u32 get_rel_symidx(struct rel_info *ri, u32 idx) +{ + idx = ri->sorted ? ri->sorted[idx] : idx; + if (ri->is_rela) { + gelf_getrela(ri->reldata, idx, &ri->rela); + return GELF_R_SYM(ri->rela.r_info); + } + gelf_getrel(ri->reldata, idx, &ri->rel); + return GELF_R_SYM(ri->rel.r_info); +} + +static u64 get_rel_offset(struct rel_info *ri, u32 x) +{ + if (ri->is_rela) { + GElf_Rela rela; + + gelf_getrela(ri->reldata, x, &rela); + return rela.r_offset; + } else { + GElf_Rel rel; + + gelf_getrel(ri->reldata, x, &rel); + return rel.r_offset; + } +} + +static int rel_cmp(const void *a, const void *b, void *r) +{ + struct rel_info *ri = r; + u64 a_offset = get_rel_offset(ri, *(const u32 *)a); + u64 b_offset = get_rel_offset(ri, *(const u32 *)b); + + return a_offset < b_offset ? -1 : (a_offset > b_offset ? 1 : 0); +} + +static int sort_rel(struct rel_info *ri) +{ + size_t sz = sizeof(ri->sorted[0]); + u32 i; + + ri->sorted = calloc(ri->nr_entries, sz); + if (!ri->sorted) + return -1; + for (i = 0; i < ri->nr_entries; i++) + ri->sorted[i] = i; + qsort_r(ri->sorted, ri->nr_entries, sz, rel_cmp, ri); + return 0; +} + +/* + * For x86_64, the GNU linker is putting IFUNC information in the relocation + * addend. + */ +static bool addend_may_be_ifunc(GElf_Ehdr *ehdr, struct rel_info *ri) +{ + return ehdr->e_machine == EM_X86_64 && ri->is_rela && + GELF_R_TYPE(ri->rela.r_info) == R_X86_64_IRELATIVE; +} + +static bool get_ifunc_name(Elf *elf, struct dso *dso, GElf_Ehdr *ehdr, + struct rel_info *ri, char *buf, size_t buf_sz) +{ + u64 addr = ri->rela.r_addend; + struct symbol *sym; + GElf_Phdr phdr; + + if (!addend_may_be_ifunc(ehdr, ri)) + return false; + + if (elf_read_program_header(elf, addr, &phdr)) + return false; + + addr -= phdr.p_vaddr - phdr.p_offset; + + sym = dso__find_symbol_nocache(dso, addr); + + /* Expecting the address to be an IFUNC or IFUNC alias */ + if (!sym || sym->start != addr || (sym->type != STT_GNU_IFUNC && !sym->ifunc_alias)) + return false; + + snprintf(buf, buf_sz, "%s@plt", sym->name); + + return true; +} + +static void exit_rel(struct rel_info *ri) +{ + zfree(&ri->sorted); +} + +static bool get_plt_sizes(struct dso *dso, GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt, + u64 *plt_header_size, u64 *plt_entry_size) +{ + switch (ehdr->e_machine) { + case EM_ARM: + *plt_header_size = 20; + *plt_entry_size = 12; + return true; + case EM_AARCH64: + *plt_header_size = 32; + *plt_entry_size = 16; + return true; + case EM_LOONGARCH: + *plt_header_size = 32; + *plt_entry_size = 16; + return true; + case EM_SPARC: + *plt_header_size = 48; + *plt_entry_size = 12; + return true; + case EM_SPARCV9: + *plt_header_size = 128; + *plt_entry_size = 32; + return true; + case EM_386: + case EM_X86_64: + *plt_entry_size = shdr_plt->sh_entsize; + /* Size is 8 or 16, if not, assume alignment indicates size */ + if (*plt_entry_size != 8 && *plt_entry_size != 16) + *plt_entry_size = shdr_plt->sh_addralign == 8 ? 8 : 16; + *plt_header_size = *plt_entry_size; + 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; + } + if (*plt_entry_size) + return true; + pr_debug("Missing PLT entry size for %s\n", dso__long_name(dso)); + return false; +} + +static bool machine_is_x86(GElf_Half e_machine) +{ + return e_machine == EM_386 || e_machine == EM_X86_64; +} + +struct rela_dyn { + GElf_Addr offset; + u32 sym_idx; +}; + +struct rela_dyn_info { + struct dso *dso; + Elf_Data *plt_got_data; + u32 nr_entries; + struct rela_dyn *sorted; + Elf_Data *dynsym_data; + Elf_Data *dynstr_data; + Elf_Data *rela_dyn_data; +}; + +static void exit_rela_dyn(struct rela_dyn_info *di) +{ + zfree(&di->sorted); +} + +static int cmp_offset(const void *a, const void *b) +{ + const struct rela_dyn *va = a; + const struct rela_dyn *vb = b; + + return va->offset < vb->offset ? -1 : (va->offset > vb->offset ? 1 : 0); +} + +static int sort_rela_dyn(struct rela_dyn_info *di) +{ + u32 i, n; + + di->sorted = calloc(di->nr_entries, sizeof(di->sorted[0])); + if (!di->sorted) + return -1; + + /* Get data for sorting: the offset and symbol index */ + for (i = 0, n = 0; i < di->nr_entries; i++) { + GElf_Rela rela; + u32 sym_idx; + + gelf_getrela(di->rela_dyn_data, i, &rela); + sym_idx = GELF_R_SYM(rela.r_info); + if (sym_idx) { + di->sorted[n].sym_idx = sym_idx; + di->sorted[n].offset = rela.r_offset; + n += 1; + } + } + + /* Sort by offset */ + di->nr_entries = n; + qsort(di->sorted, n, sizeof(di->sorted[0]), cmp_offset); + + return 0; +} + +static void get_rela_dyn_info(Elf *elf, GElf_Ehdr *ehdr, struct rela_dyn_info *di, Elf_Scn *scn) +{ + GElf_Shdr rela_dyn_shdr; + GElf_Shdr shdr; + + di->plt_got_data = elf_getdata(scn, NULL); + + scn = elf_section_by_name(elf, ehdr, &rela_dyn_shdr, ".rela.dyn", NULL); + if (!scn || !rela_dyn_shdr.sh_link || !rela_dyn_shdr.sh_entsize) + return; + + di->nr_entries = rela_dyn_shdr.sh_size / rela_dyn_shdr.sh_entsize; + di->rela_dyn_data = elf_getdata(scn, NULL); + + scn = elf_getscn(elf, rela_dyn_shdr.sh_link); + if (!scn || !gelf_getshdr(scn, &shdr) || !shdr.sh_link) + return; + + di->dynsym_data = elf_getdata(scn, NULL); + di->dynstr_data = elf_getdata(elf_getscn(elf, shdr.sh_link), NULL); + + if (!di->plt_got_data || !di->dynstr_data || !di->dynsym_data || !di->rela_dyn_data) + return; + + /* Sort into offset order */ + sort_rela_dyn(di); +} + +/* Get instruction displacement from a plt entry for x86_64 */ +static u32 get_x86_64_plt_disp(const u8 *p) +{ + u8 endbr64[] = {0xf3, 0x0f, 0x1e, 0xfa}; + int n = 0; + + /* Skip endbr64 */ + if (!memcmp(p, endbr64, sizeof(endbr64))) + n += sizeof(endbr64); + /* Skip bnd prefix */ + if (p[n] == 0xf2) + n += 1; + /* jmp with 4-byte displacement */ + if (p[n] == 0xff && p[n + 1] == 0x25) { + u32 disp; + + n += 2; + /* Also add offset from start of entry to end of instruction */ + memcpy(&disp, p + n, sizeof(disp)); + return n + 4 + le32toh(disp); + } + return 0; +} + +static bool get_plt_got_name(GElf_Shdr *shdr, size_t i, + struct rela_dyn_info *di, + char *buf, size_t buf_sz) +{ + struct rela_dyn vi, *vr; + const char *sym_name; + char *demangled; + GElf_Sym sym; + bool result; + u32 disp; + + if (!di->sorted) + return false; + + disp = get_x86_64_plt_disp(di->plt_got_data->d_buf + i); + if (!disp) + return false; + + /* Compute target offset of the .plt.got entry */ + vi.offset = shdr->sh_offset + di->plt_got_data->d_off + i + disp; + + /* Find that offset in .rela.dyn (sorted by offset) */ + vr = bsearch(&vi, di->sorted, di->nr_entries, sizeof(di->sorted[0]), cmp_offset); + if (!vr) + return false; + + /* Get the associated symbol */ + gelf_getsym(di->dynsym_data, vr->sym_idx, &sym); + sym_name = elf_sym__name(&sym, di->dynstr_data); + demangled = dso__demangle_sym(di->dso, /*kmodule=*/0, sym_name); + if (demangled != NULL) + sym_name = demangled; + + snprintf(buf, buf_sz, "%s@plt", sym_name); + + result = *sym_name; + + free(demangled); + + return result; +} + +static int dso__synthesize_plt_got_symbols(struct dso *dso, Elf *elf, + GElf_Ehdr *ehdr, + char *buf, size_t buf_sz) +{ + struct rela_dyn_info di = { .dso = dso }; + struct symbol *sym; + GElf_Shdr shdr; + Elf_Scn *scn; + int err = -1; + size_t i; + + scn = elf_section_by_name(elf, ehdr, &shdr, ".plt.got", NULL); + if (!scn || !shdr.sh_entsize) + return 0; + + if (ehdr->e_machine == EM_X86_64) + get_rela_dyn_info(elf, ehdr, &di, scn); + + for (i = 0; i < shdr.sh_size; i += shdr.sh_entsize) { + if (!get_plt_got_name(&shdr, i, &di, buf, buf_sz)) + snprintf(buf, buf_sz, "offset_%#" PRIx64 "@plt", (u64)shdr.sh_offset + i); + sym = symbol__new(shdr.sh_offset + i, shdr.sh_entsize, STB_GLOBAL, STT_FUNC, buf); + if (!sym) + goto out; + symbols__insert(dso__symbols(dso), sym); + } + err = 0; +out: + exit_rela_dyn(&di); + return err; +} /* * We need to check if we have a .dynsym, so that we can handle the @@ -163,59 +601,106 @@ static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep, * 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, struct map *map, - symbol_filter_t filter) +int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss) { - uint32_t nr_rel_entries, idx; + uint32_t idx; GElf_Sym sym; - u64 plt_offset; - GElf_Shdr shdr_plt; - struct symbol *f; + u64 plt_offset, plt_header_size, plt_entry_size; + GElf_Shdr shdr_plt, plt_sec_shdr; + struct symbol *f, *plt_sym; GElf_Shdr shdr_rel_plt, shdr_dynsym; - Elf_Data *reldata, *syms, *symstrs; + Elf_Data *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; + int nr = 0, err = -1; + struct rel_info ri = { .is_rela = false }; + bool lazy_plt; elf = ss->elf; ehdr = ss->ehdr; - scn_dynsym = ss->dynsym; - shdr_dynsym = ss->dynshdr; - dynsym_idx = ss->dynsym_idx; + if (!elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL)) + return 0; - if (scn_dynsym == NULL) + /* + * A symbol from a previous section (e.g. .init) can have been expanded + * by symbols__fixup_end() to overlap .plt. Truncate it before adding + * a symbol for .plt header. + */ + f = dso__find_symbol_nocache(dso, shdr_plt.sh_offset); + if (f && f->start < shdr_plt.sh_offset && f->end > shdr_plt.sh_offset) + f->end = shdr_plt.sh_offset; + + if (!get_plt_sizes(dso, &ehdr, &shdr_plt, &plt_header_size, &plt_entry_size)) + return 0; + + /* Add a symbol for .plt header */ + plt_sym = symbol__new(shdr_plt.sh_offset, plt_header_size, STB_GLOBAL, STT_FUNC, ".plt"); + if (!plt_sym) + goto out_elf_end; + symbols__insert(dso__symbols(dso), plt_sym); + + /* Only x86 has .plt.got */ + if (machine_is_x86(ehdr.e_machine) && + dso__synthesize_plt_got_symbols(dso, elf, &ehdr, sympltname, sizeof(sympltname))) goto out_elf_end; + /* Only x86 has .plt.sec */ + if (machine_is_x86(ehdr.e_machine) && + elf_section_by_name(elf, &ehdr, &plt_sec_shdr, ".plt.sec", NULL)) { + if (!get_plt_sizes(dso, &ehdr, &plt_sec_shdr, &plt_header_size, &plt_entry_size)) + return 0; + /* Extend .plt symbol to entire .plt */ + plt_sym->end = plt_sym->start + shdr_plt.sh_size; + /* Use .plt.sec offset */ + plt_offset = plt_sec_shdr.sh_offset; + lazy_plt = false; + } else { + plt_offset = shdr_plt.sh_offset; + lazy_plt = true; + } + 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; + return 0; } - err = -1; + if (shdr_rel_plt.sh_type != SHT_RELA && + shdr_rel_plt.sh_type != SHT_REL) + return 0; - if (shdr_rel_plt.sh_link != dynsym_idx) - goto out_elf_end; + if (!shdr_rel_plt.sh_link) + return 0; - if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL) + if (shdr_rel_plt.sh_link == ss->dynsym_idx) { + scn_dynsym = ss->dynsym; + shdr_dynsym = ss->dynshdr; + } else if (shdr_rel_plt.sh_link == ss->symtab_idx) { + /* + * A static executable can have a .plt due to IFUNCs, in which + * case .symtab is used not .dynsym. + */ + scn_dynsym = ss->symtab; + shdr_dynsym = ss->symshdr; + } else { goto out_elf_end; + } + + if (!scn_dynsym) + return 0; /* * 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) + ri.reldata = elf_getdata(scn_plt_rel, NULL); + if (!ri.reldata) goto out_elf_end; syms = elf_getdata(scn_dynsym, NULL); @@ -233,62 +718,61 @@ int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map * 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; + ri.nr_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize; - if (shdr_rel_plt.sh_type == SHT_RELA) { - GElf_Rela pos_mem, *pos; + ri.is_rela = shdr_rel_plt.sh_type == SHT_RELA; - elf_section__for_each_rela(reldata, pos, pos_mem, idx, - nr_rel_entries) { - symidx = GELF_R_SYM(pos->r_info); - plt_offset += shdr_plt.sh_entsize; - gelf_getsym(syms, symidx, &sym); - snprintf(sympltname, sizeof(sympltname), - "%s@plt", elf_sym__name(&sym, symstrs)); + if (lazy_plt) { + /* + * Assume a .plt with the same number of entries as the number + * of relocation entries is not lazy and does not have a header. + */ + if (ri.nr_entries * plt_entry_size == shdr_plt.sh_size) + dso__delete_symbol(dso, plt_sym); + else + plt_offset += plt_header_size; + } - f = symbol__new(plt_offset, shdr_plt.sh_entsize, - STB_GLOBAL, sympltname); - if (!f) - goto out_elf_end; + /* + * x86 doesn't insert IFUNC relocations in .plt order, so sort to get + * back in order. + */ + if (machine_is_x86(ehdr.e_machine) && sort_rel(&ri)) + goto out_elf_end; - if (filter && filter(map, f)) - symbol__delete(f); - else { - symbols__insert(&dso->symbols[map->type], 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) { - symidx = GELF_R_SYM(pos->r_info); - plt_offset += shdr_plt.sh_entsize; - gelf_getsym(syms, symidx, &sym); + for (idx = 0; idx < ri.nr_entries; idx++) { + const char *elf_name = NULL; + char *demangled = NULL; + + gelf_getsym(syms, get_rel_symidx(&ri, idx), &sym); + + elf_name = elf_sym__name(&sym, symstrs); + demangled = dso__demangle_sym(dso, /*kmodule=*/0, elf_name); + if (demangled) + elf_name = demangled; + if (*elf_name) + snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_name); + else if (!get_ifunc_name(elf, dso, &ehdr, &ri, sympltname, sizeof(sympltname))) snprintf(sympltname, sizeof(sympltname), - "%s@plt", elf_sym__name(&sym, symstrs)); + "offset_%#" PRIx64 "@plt", plt_offset); + free(demangled); - f = symbol__new(plt_offset, shdr_plt.sh_entsize, - STB_GLOBAL, sympltname); - if (!f) - goto out_elf_end; + f = symbol__new(plt_offset, plt_entry_size, STB_GLOBAL, STT_FUNC, sympltname); + if (!f) + goto out_elf_end; - if (filter && filter(map, f)) - symbol__delete(f); - else { - symbols__insert(&dso->symbols[map->type], f); - ++nr; - } - } + plt_offset += plt_entry_size; + symbols__insert(dso__symbols(dso), f); + ++nr; } err = 0; out_elf_end: + exit_rel(&ri); if (err == 0) return nr; pr_debug("%s: problems reading %s PLT info.\n", - __func__, dso->long_name); + __func__, dso__long_name(dso)); return 0; } @@ -365,7 +849,7 @@ static int elf_read_build_id(Elf *elf, void *bf, size_t size) size_t sz = min(size, descsz); memcpy(bf, ptr, sz); memset(bf + sz, 0, size - sz); - err = descsz; + err = sz; break; } } @@ -376,11 +860,16 @@ out: return err; } -int filename__read_build_id(const char *filename, void *bf, size_t size) +static int read_build_id(const char *filename, struct build_id *bid) { - int fd, err = -1; + size_t size = sizeof(bid->data); + int fd, err; Elf *elf; + err = libbfd__read_build_id(filename, bid); + if (err >= 0) + goto out; + if (size < BUILD_ID_SIZE) goto out; @@ -394,7 +883,9 @@ int filename__read_build_id(const char *filename, void *bf, size_t size) goto out_close; } - err = elf_read_build_id(elf, bf, size); + err = elf_read_build_id(elf, bid->data, size); + if (err > 0) + bid->size = err; elf_end(elf); out_close: @@ -403,12 +894,45 @@ out: return err; } -int sysfs__read_build_id(const char *filename, void *build_id, size_t size) +int filename__read_build_id(const char *filename, struct build_id *bid) { - int fd, err = -1; + struct kmod_path m = { .name = NULL, }; + char path[PATH_MAX]; + int err; - if (size < BUILD_ID_SIZE) - goto out; + if (!filename) + return -EFAULT; + if (!is_regular_file(filename)) + return -EWOULDBLOCK; + + 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) @@ -430,8 +954,9 @@ int sysfs__read_build_id(const char *filename, void *build_id, size_t size) break; if (memcmp(bf, "GNU", sizeof("GNU")) == 0) { size_t sz = min(descsz, size); - if (read(fd, build_id, sz) == (ssize_t)sz) { - memset(build_id + sz, 0, size - sz); + if (read(fd, bid->data, sz) == (ssize_t)sz) { + memset(bid->data + sz, 0, size - sz); + bid->size = sz; err = 0; break; } @@ -439,6 +964,12 @@ int sysfs__read_build_id(const char *filename, void *build_id, size_t size) 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; } @@ -459,6 +990,10 @@ int filename__read_debuglink(const char *filename, char *debuglink, Elf_Scn *sec; Elf_Kind ek; + err = libbfd_filename__read_debuglink(filename, debuglink, size); + if (err >= 0) + goto out; + fd = open(filename, O_RDONLY); if (fd < 0) goto out; @@ -471,60 +1006,35 @@ int filename__read_debuglink(const char *filename, char *debuglink, ek = elf_kind(elf); if (ek != ELF_K_ELF) - goto out_close; + goto out_elf_end; if (gelf_getehdr(elf, &ehdr) == NULL) { pr_err("%s: cannot get elf header.\n", __func__); - goto out_close; + goto out_elf_end; } sec = elf_section_by_name(elf, &ehdr, &shdr, ".gnu_debuglink", NULL); if (sec == NULL) - goto out_close; + goto out_elf_end; data = elf_getdata(sec, NULL); if (data == NULL) - goto out_close; + goto out_elf_end; /* the start of this section is a zero-terminated string */ strncpy(debuglink, data->d_buf, size); - elf_end(elf); + err = 0; +out_elf_end: + elf_end(elf); out_close: close(fd); out: return err; } -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; @@ -537,50 +1047,174 @@ bool symsrc__has_symtab(struct symsrc *ss) void symsrc__destroy(struct symsrc *ss) { - free(ss->name); + 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; +} + +static Elf *read_gnu_debugdata(struct dso *dso, Elf *elf, const char *name, int *fd_ret) +{ + Elf *elf_embedded; + GElf_Ehdr ehdr; + GElf_Shdr shdr; + Elf_Scn *scn; + Elf_Data *scn_data; + FILE *wrapped; + size_t shndx; + char temp_filename[] = "/tmp/perf.gnu_debugdata.elf.XXXXXX"; + int ret, temp_fd; + + if (gelf_getehdr(elf, &ehdr) == NULL) { + pr_debug("%s: cannot read %s ELF file.\n", __func__, name); + *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF; + return NULL; + } + + scn = elf_section_by_name(elf, &ehdr, &shdr, ".gnu_debugdata", &shndx); + if (!scn) { + *dso__load_errno(dso) = -ENOENT; + return NULL; + } + + if (shdr.sh_type == SHT_NOBITS) { + pr_debug("%s: .gnu_debugdata of ELF file %s has no data.\n", __func__, name); + *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF; + return NULL; + } + + scn_data = elf_rawdata(scn, NULL); + if (!scn_data) { + pr_debug("%s: error reading .gnu_debugdata of %s: %s\n", __func__, + name, elf_errmsg(-1)); + *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF; + return NULL; + } + + wrapped = fmemopen(scn_data->d_buf, scn_data->d_size, "r"); + if (!wrapped) { + pr_debug("%s: fmemopen: %s\n", __func__, strerror(errno)); + *dso__load_errno(dso) = -errno; + return NULL; + } + + temp_fd = mkstemp(temp_filename); + if (temp_fd < 0) { + pr_debug("%s: mkstemp: %s\n", __func__, strerror(errno)); + *dso__load_errno(dso) = -errno; + fclose(wrapped); + return NULL; + } + unlink(temp_filename); + + ret = lzma_decompress_stream_to_file(wrapped, temp_fd); + fclose(wrapped); + if (ret < 0) { + *dso__load_errno(dso) = -errno; + close(temp_fd); + return NULL; + } + + elf_embedded = elf_begin(temp_fd, PERF_ELF_C_READ_MMAP, NULL); + if (!elf_embedded) { + pr_debug("%s: error reading .gnu_debugdata of %s: %s\n", __func__, + name, elf_errmsg(-1)); + *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF; + close(temp_fd); + return NULL; + } + pr_debug("%s: using .gnu_debugdata of %s\n", __func__, name); + *fd_ret = temp_fd; + return elf_embedded; +} + int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, enum dso_binary_type type) { - int err = -1; GElf_Ehdr ehdr; Elf *elf; int fd; - fd = open(name, O_RDONLY); - if (fd < 0) - return -1; + if (dso__needs_decompress(dso)) { + fd = dso__decompress_kmodule_fd(dso, name); + if (fd < 0) + return -1; + + type = dso__symtab_type(dso); + } else { + fd = open(name, O_RDONLY); + if (fd < 0) { + *dso__load_errno(dso) = 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) = DSO_LOAD_ERRNO__INVALID_ELF; goto out_close; } + if (type == DSO_BINARY_TYPE__GNU_DEBUGDATA) { + int new_fd; + Elf *embedded = read_gnu_debugdata(dso, elf, name, &new_fd); + + if (!embedded) + goto out_close; + + elf_end(elf); + close(fd); + fd = new_fd; + elf = embedded; + } + if (gelf_getehdr(elf, &ehdr) == NULL) { + *dso__load_errno(dso) = 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])) + if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) { + *dso__load_errno(dso) = DSO_LOAD_ERRNO__INTERNAL_ERROR; goto out_elf_end; + } /* Always reject images with a mismatched build-id: */ - if (dso->has_build_id) { + if (dso__has_build_id(dso) && !symbol_conf.ignore_vmlinux_buildid) { u8 build_id[BUILD_ID_SIZE]; + struct build_id bid; + int size; - if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) + size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE); + if (size <= 0) { + *dso__load_errno(dso) = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID; goto out_elf_end; + } - if (!dso__build_id_equal(dso, build_id)) + 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) = DSO_LOAD_ERRNO__MISMATCHING_BUILDID; goto out_elf_end; + } } + ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64); + + ss->symtab_idx = 0; ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab", - NULL); + &ss->symtab_idx); if (ss->symshdr.sh_type != SHT_SYMTAB) ss->symtab = NULL; @@ -596,19 +1230,16 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, if (ss->opdshdr.sh_type != SHT_PROGBITS) ss->opdsec = NULL; - if (dso->kernel == DSO_TYPE_USER) { - GElf_Shdr shdr; - ss->adjust_symbols = (ehdr.e_type == ET_EXEC || - elf_section_by_name(elf, &ehdr, &shdr, - ".gnu.prelink_undo", - NULL) != NULL); - } else { - ss->adjust_symbols = 0; - } + if (dso__kernel(dso) == DSO_SPACE__USER) + ss->adjust_symbols = true; + else + ss->adjust_symbols = elf__needs_adjust_symbols(ehdr); ss->name = strdup(name); - if (!ss->name) + if (!ss->name) { + *dso__load_errno(dso) = errno; goto out_elf_end; + } ss->elf = elf; ss->fd = fd; @@ -621,39 +1252,258 @@ out_elf_end: elf_end(elf); out_close: close(fd); - return err; + return -1; } -int dso__load_sym(struct dso *dso, struct map *map, - struct symsrc *syms_ss, struct symsrc *runtime_ss, - symbol_filter_t filter, int kmodule) +static bool is_exe_text(int flags) { - struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL; - struct map *curr_map = map; - struct dso *curr_dso = dso; - Elf_Data *symstrs, *secstrs; + return (flags & (SHF_ALLOC | SHF_EXECINSTR)) == (SHF_ALLOC | SHF_EXECINSTR); +} + +/* + * Some executable module sections like .noinstr.text might be laid out with + * .text so they can use the same mapping (memory address to file offset). + * Check if that is the case. Refer to kernel layout_sections(). Return the + * maximum offset. + */ +static u64 max_text_section(Elf *elf, GElf_Ehdr *ehdr) +{ + Elf_Scn *sec = NULL; + GElf_Shdr shdr; + u64 offs = 0; + + /* Doesn't work for some arch */ + if (ehdr->e_machine == EM_PARISC || + ehdr->e_machine == EM_ALPHA) + return 0; + + /* ELF is corrupted/truncated, avoid calling elf_strptr. */ + if (!elf_rawdata(elf_getscn(elf, ehdr->e_shstrndx), NULL)) + return 0; + + while ((sec = elf_nextscn(elf, sec)) != NULL) { + char *sec_name; + + if (!gelf_getshdr(sec, &shdr)) + break; + + if (!is_exe_text(shdr.sh_flags)) + continue; + + /* .init and .exit sections are not placed with .text */ + sec_name = elf_strptr(elf, ehdr->e_shstrndx, shdr.sh_name); + if (!sec_name || + strstarts(sec_name, ".init") || + strstarts(sec_name, ".exit")) + break; + + /* Must be next to previous, assumes .text is first */ + if (offs && PERF_ALIGN(offs, shdr.sh_addralign ?: 1) != shdr.sh_offset) + break; + + offs = shdr.sh_offset + shdr.sh_size; + } + + return offs; +} + +/** + * 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, + const char *section_name, + bool adjust_kernel_syms, bool kmodule, bool *remap_kernel, + u64 max_text_sh_offset) +{ + 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, (dso__short_name(curr_dso) + dso__short_name_len(dso))) == 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(dso) && !kmodule) { + *remap_kernel = false; + map__set_start(map, shdr->sh_addr + ref_reloc(kmap)); + map__set_end(map, map__start(map) + shdr->sh_size); + map__set_pgoff(map, shdr->sh_offset); + map__set_mapping_type(map, MAPPING_TYPE__DSO); + /* Ensure maps are correctly ordered */ + if (kmaps) { + int err; + struct map *tmp = map__get(map); + + maps__remove(kmaps, map); + err = maps__insert(kmaps, map); + map__put(tmp); + if (err) + return err; + } + } + + /* + * 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__set_pgoff(map, shdr->sh_offset); + } + + dso__put(*curr_dsop); + *curr_dsop = dso__get(dso); + return 0; + } + + if (!kmap) + return 0; + + /* + * perf does not record module section addresses except for .text, but + * some sections can use the same mapping as .text. + */ + if (kmodule && adjust_kernel_syms && is_exe_text(shdr->sh_flags) && + shdr->sh_offset <= max_text_sh_offset) { + dso__put(*curr_dsop); + *curr_dsop = dso__get(dso); + return 0; + } + + snprintf(dso_name, sizeof(dso_name), "%s%s", dso__short_name(dso), 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(map) + shdr->sh_offset; + + curr_dso = dso__new(dso_name); + if (curr_dso == NULL) + return -1; + dso__set_kernel(curr_dso, dso__kernel(dso)); + RC_CHK_ACCESS(curr_dso)->long_name = dso__long_name(dso); + RC_CHK_ACCESS(curr_dso)->long_name_len = dso__long_name_len(dso); + dso__set_binary_type(curr_dso, dso__binary_type(dso)); + dso__set_adjust_symbols(curr_dso, dso__adjust_symbols(dso)); + curr_map = map__new2(start, curr_dso); + if (curr_map == NULL) { + dso__put(curr_dso); + return -1; + } + if (dso__kernel(curr_dso)) + map__kmap(curr_map)->kmaps = kmaps; + + if (adjust_kernel_syms) { + map__set_start(curr_map, shdr->sh_addr + ref_reloc(kmap)); + map__set_end(curr_map, map__start(curr_map) + shdr->sh_size); + map__set_pgoff(curr_map, shdr->sh_offset); + } else { + map__set_mapping_type(curr_map, MAPPING_TYPE__IDENTITY); + } + dso__set_symtab_type(curr_dso, dso__symtab_type(dso)); + if (maps__insert(kmaps, curr_map)) { + dso__put(curr_dso); + map__put(curr_map); + return -1; + } + dsos__add(&maps__machine(kmaps)->dsos, curr_dso); + dso__set_loaded(curr_dso); + dso__put(*curr_dsop); + *curr_dsop = curr_dso; + } else { + dso__put(*curr_dsop); + *curr_dsop = dso__get(map__dso(curr_map)); + } + map__put(curr_map); + + 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(dso) ? map__kmap(map) : NULL; + struct maps *kmaps = kmap ? map__kmaps(map) : NULL; + struct dso *curr_dso = NULL; + 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; + u64 max_text_sh_offset = 0; - dso->symtab_type = syms_ss->type; - - if (!syms_ss->symtab) { - syms_ss->symtab = syms_ss->dynsym; - syms_ss->symshdr = syms_ss->dynshdr; - } + if (kmap && !kmaps) + return -1; elf = syms_ss->elf; ehdr = syms_ss->ehdr; - sec = syms_ss->symtab; - shdr = syms_ss->symshdr; + 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__set_text_offset(dso, tshdr.sh_addr - tshdr.sh_offset); + dso__set_text_end(dso, tshdr.sh_offset + tshdr.sh_size); + } if (runtime_ss->opdsec) opddata = elf_rawdata(runtime_ss->opdsec, NULL); @@ -670,18 +1520,63 @@ int dso__load_sym(struct dso *dso, struct map *map, 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 = elf_getdata(sec_strndx, NULL); - if (secstrs == NULL) + 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)); - dso->adjust_symbols = runtime_ss->adjust_symbols; + + /* + * 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__set_reloc(map, 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__set_reloc(map, map__start(map) - dso__text_offset(dso)); + + dso__set_adjust_symbols(dso, runtime_ss->adjust_symbols || ref_reloc(kmap)); + /* + * Initial kernel and module mappings do not map to the dso. + * Flag the fixups. + */ + if (dso__kernel(dso)) { + remap_kernel = true; + adjust_kernel_syms = dso__adjust_symbols(dso); + } + + if (kmodule && adjust_kernel_syms) + max_text_sh_offset = max_text_section(runtime_ss->elf, &runtime_ss->ehdr); + + curr_dso = dso__get(dso); elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { struct symbol *f; const char *elf_name = elf_sym__name(&sym, symstrs); @@ -690,20 +1585,21 @@ int dso__load_sym(struct dso *dso, struct map *map, const char *section_name; bool used_opd = false; - if (kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name && - strcmp(elf_name, kmap->ref_reloc_sym->name) == 0) - kmap->ref_reloc_sym->unrelocated_addr = sym.st_value; - - if (!is_label && !elf_sym__is_a(&sym, map->type)) + 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) { - if (!strcmp(elf_name, "$a") || - !strcmp(elf_name, "$d") || - !strcmp(elf_name, "$t")) + if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) { + if (elf_name[0] == '$' && strchr("adtx", elf_name[1]) + && (elf_name[2] == '\0' || elf_name[2] == '.')) + continue; + } + + /* Reject RISCV ELF "mapping symbols" */ + if (ehdr.e_machine == EM_RISCV) { + if (elf_name[0] == '$' && strchr("dx", elf_name[1])) continue; } @@ -715,6 +1611,7 @@ int dso__load_sym(struct dso *dso, struct map *map, 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 @@ -727,13 +1624,41 @@ int dso__load_sym(struct dso *dso, struct map *map, if (sym.st_shndx == SHN_ABS) continue; - sec = elf_getscn(runtime_ss->elf, sym.st_shndx); + sec = elf_getscn(syms_ss->elf, sym.st_shndx); if (!sec) goto out_elf_end; gelf_getshdr(sec, &shdr); - if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type)) + /* + * If the attribute bit SHF_ALLOC is not set, the section + * doesn't occupy memory during process execution. + * E.g. ".gnu.warning.*" section is used by linker to generate + * warnings when calling deprecated functions, the symbols in + * the section aren't loaded to memory during process execution, + * so skip them. + */ + if (!(shdr.sh_flags & SHF_ALLOC)) + continue; + + 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); @@ -741,111 +1666,1268 @@ int dso__load_sym(struct dso *dso, struct map *map, /* On ARM, symbols for thumb functions have 1 added to * the symbol address as a flag - remove it */ if ((ehdr.e_machine == EM_ARM) && - (map->type == MAP__FUNCTION) && + (GELF_ST_TYPE(sym.st_info) == STT_FUNC) && (sym.st_value & 1)) --sym.st_value; - if (dso->kernel != DSO_TYPE_USER || kmodule) { - char dso_name[PATH_MAX]; - - if (strcmp(section_name, - (curr_dso->short_name + - dso->short_name_len)) == 0) - goto new_symbol; - - if (strcmp(section_name, ".text") == 0) { - curr_map = map; - curr_dso = dso; - goto new_symbol; + if (dso__kernel(dso)) { + if (dso__process_kernel_symbol(dso, map, &sym, &shdr, + kmaps, kmap, &curr_dso, + section_name, + adjust_kernel_syms, + kmodule, + &remap_kernel, + max_text_sh_offset)) + 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; } - - snprintf(dso_name, sizeof(dso_name), - "%s%s", dso->short_name, section_name); - - curr_map = map_groups__find_by_name(kmap->kmaps, map->type, 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) - goto out_elf_end; - 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, - map->type); - if (curr_map == NULL) { - dso__delete(curr_dso); - goto out_elf_end; - } - curr_map->map_ip = identity__map_ip; - curr_map->unmap_ip = identity__map_ip; - curr_dso->symtab_type = dso->symtab_type; - map_groups__insert(kmap->kmaps, curr_map); - dsos__add(&dso->node, curr_dso); - dso__set_loaded(curr_dso, map->type); - } else - curr_dso = curr_map->dso; - - goto new_symbol; } - if ((used_opd && runtime_ss->adjust_symbols) - || (!used_opd && syms_ss->adjust_symbols)) { - 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); - sym.st_value -= shdr.sh_addr - shdr.sh_offset; - } - /* - * 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 (symbol_conf.demangle) { - demangled = bfd_demangle(NULL, elf_name, - DMGL_PARAMS | DMGL_ANSI); - if (demangled != NULL) - elf_name = demangled; - } -new_symbol: + demangled = dso__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), elf_name); + GELF_ST_BIND(sym.st_info), + GELF_ST_TYPE(sym.st_info), elf_name); free(demangled); if (!f) goto out_elf_end; - if (filter && filter(curr_map, f)) - symbol__delete(f); - else { - symbols__insert(&curr_dso->symbols[curr_map->type], f); - nr++; - } + arch__sym_update(f, &sym); + + __symbols__insert(dso__symbols(curr_dso), f, dso__kernel(dso)); + nr++; } + dso__put(curr_dso); /* * For misannotated, zeroed, ASM function sizes. */ if (nr > 0) { - symbols__fixup_duplicate(&dso->symbols[map->type]); - symbols__fixup_end(&dso->symbols[map->type]); + symbols__fixup_end(dso__symbols(dso), false); + symbols__fixup_duplicate(dso__symbols(dso)); if (kmap) { /* * We need to fixup this here too because we create new * maps here, for things like vsyscall sections. */ - __map_groups__fixup_end(kmap->kmaps, map->type); + maps__fixup_end(kmaps); } } - err = nr; + return nr; out_elf_end: + dso__put(curr_dso); + return -1; +} + +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__set_symtab_type(dso, syms_ss->type); + dso__set_is_64_bit(dso, syms_ss->is_64_bit); + dso__set_rel(dso, 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(dso)); + + 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(dso)) + 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; + nr += err; + } + + /* + * The .gnu_debugdata is a special situation: it contains a symbol + * table, but the runtime file may also contain dynsym entries which are + * not present there. We need to load both. + */ + if (syms_ss->type == DSO_BINARY_TYPE__GNU_DEBUGDATA && runtime_ss->dynsym) { + err = dso__load_sym_internal(dso, map, runtime_ss, runtime_ss, + kmodule, 1); + if (err < 0) + return err; + nr += err; + } + + return nr; +} + +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); |