2988 lines · c
1// SPDX-License-Identifier: GPL-2.02#include <fcntl.h>3#include <stdio.h>4#include <errno.h>5#include <stdlib.h>6#include <string.h>7#include <unistd.h>8#include <inttypes.h>9 10#include "dso.h"11#include "map.h"12#include "maps.h"13#include "symbol.h"14#include "symsrc.h"15#include "demangle-cxx.h"16#include "demangle-ocaml.h"17#include "demangle-java.h"18#include "demangle-rust.h"19#include "machine.h"20#include "vdso.h"21#include "debug.h"22#include "util/copyfile.h"23#include <linux/ctype.h>24#include <linux/kernel.h>25#include <linux/zalloc.h>26#include <linux/string.h>27#include <symbol/kallsyms.h>28#include <internal/lib.h>29 30#ifdef HAVE_LIBBFD_SUPPORT31#define PACKAGE 'perf'32#include <bfd.h>33#endif34 35#if defined(HAVE_LIBBFD_SUPPORT) || defined(HAVE_CPLUS_DEMANGLE_SUPPORT)36#ifndef DMGL_PARAMS37#define DMGL_PARAMS (1 << 0) /* Include function args */38#define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */39#endif40#endif41 42#ifndef EM_AARCH6443#define EM_AARCH64 183 /* ARM 64 bit */44#endif45 46#ifndef EM_LOONGARCH47#define EM_LOONGARCH 25848#endif49 50#ifndef ELF32_ST_VISIBILITY51#define ELF32_ST_VISIBILITY(o) ((o) & 0x03)52#endif53 54/* For ELF64 the definitions are the same. */55#ifndef ELF64_ST_VISIBILITY56#define ELF64_ST_VISIBILITY(o) ELF32_ST_VISIBILITY (o)57#endif58 59/* How to extract information held in the st_other field. */60#ifndef GELF_ST_VISIBILITY61#define GELF_ST_VISIBILITY(val) ELF64_ST_VISIBILITY (val)62#endif63 64typedef Elf64_Nhdr GElf_Nhdr;65 66 67#ifndef HAVE_ELF_GETPHDRNUM_SUPPORT68static int elf_getphdrnum(Elf *elf, size_t *dst)69{70 GElf_Ehdr gehdr;71 GElf_Ehdr *ehdr;72 73 ehdr = gelf_getehdr(elf, &gehdr);74 if (!ehdr)75 return -1;76 77 *dst = ehdr->e_phnum;78 79 return 0;80}81#endif82 83#ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT84static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)85{86 pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);87 return -1;88}89#endif90 91#ifndef NT_GNU_BUILD_ID92#define NT_GNU_BUILD_ID 393#endif94 95/**96 * elf_symtab__for_each_symbol - iterate thru all the symbols97 *98 * @syms: struct elf_symtab instance to iterate99 * @idx: uint32_t idx100 * @sym: GElf_Sym iterator101 */102#define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \103 for (idx = 0, gelf_getsym(syms, idx, &sym);\104 idx < nr_syms; \105 idx++, gelf_getsym(syms, idx, &sym))106 107static inline uint8_t elf_sym__type(const GElf_Sym *sym)108{109 return GELF_ST_TYPE(sym->st_info);110}111 112static inline uint8_t elf_sym__visibility(const GElf_Sym *sym)113{114 return GELF_ST_VISIBILITY(sym->st_other);115}116 117#ifndef STT_GNU_IFUNC118#define STT_GNU_IFUNC 10119#endif120 121static inline int elf_sym__is_function(const GElf_Sym *sym)122{123 return (elf_sym__type(sym) == STT_FUNC ||124 elf_sym__type(sym) == STT_GNU_IFUNC) &&125 sym->st_name != 0 &&126 sym->st_shndx != SHN_UNDEF;127}128 129static inline bool elf_sym__is_object(const GElf_Sym *sym)130{131 return elf_sym__type(sym) == STT_OBJECT &&132 sym->st_name != 0 &&133 sym->st_shndx != SHN_UNDEF;134}135 136static inline int elf_sym__is_label(const GElf_Sym *sym)137{138 return elf_sym__type(sym) == STT_NOTYPE &&139 sym->st_name != 0 &&140 sym->st_shndx != SHN_UNDEF &&141 sym->st_shndx != SHN_ABS &&142 elf_sym__visibility(sym) != STV_HIDDEN &&143 elf_sym__visibility(sym) != STV_INTERNAL;144}145 146static bool elf_sym__filter(GElf_Sym *sym)147{148 return elf_sym__is_function(sym) || elf_sym__is_object(sym);149}150 151static inline const char *elf_sym__name(const GElf_Sym *sym,152 const Elf_Data *symstrs)153{154 return symstrs->d_buf + sym->st_name;155}156 157static inline const char *elf_sec__name(const GElf_Shdr *shdr,158 const Elf_Data *secstrs)159{160 return secstrs->d_buf + shdr->sh_name;161}162 163static inline int elf_sec__is_text(const GElf_Shdr *shdr,164 const Elf_Data *secstrs)165{166 return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;167}168 169static inline bool elf_sec__is_data(const GElf_Shdr *shdr,170 const Elf_Data *secstrs)171{172 return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;173}174 175static bool elf_sec__filter(GElf_Shdr *shdr, Elf_Data *secstrs)176{177 return elf_sec__is_text(shdr, secstrs) ||178 elf_sec__is_data(shdr, secstrs);179}180 181static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)182{183 Elf_Scn *sec = NULL;184 GElf_Shdr shdr;185 size_t cnt = 1;186 187 while ((sec = elf_nextscn(elf, sec)) != NULL) {188 gelf_getshdr(sec, &shdr);189 190 if ((addr >= shdr.sh_addr) &&191 (addr < (shdr.sh_addr + shdr.sh_size)))192 return cnt;193 194 ++cnt;195 }196 197 return -1;198}199 200Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,201 GElf_Shdr *shp, const char *name, size_t *idx)202{203 Elf_Scn *sec = NULL;204 size_t cnt = 1;205 206 /* ELF is corrupted/truncated, avoid calling elf_strptr. */207 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))208 return NULL;209 210 while ((sec = elf_nextscn(elf, sec)) != NULL) {211 char *str;212 213 gelf_getshdr(sec, shp);214 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);215 if (str && !strcmp(name, str)) {216 if (idx)217 *idx = cnt;218 return sec;219 }220 ++cnt;221 }222 223 return NULL;224}225 226bool filename__has_section(const char *filename, const char *sec)227{228 int fd;229 Elf *elf;230 GElf_Ehdr ehdr;231 GElf_Shdr shdr;232 bool found = false;233 234 fd = open(filename, O_RDONLY);235 if (fd < 0)236 return false;237 238 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);239 if (elf == NULL)240 goto out;241 242 if (gelf_getehdr(elf, &ehdr) == NULL)243 goto elf_out;244 245 found = !!elf_section_by_name(elf, &ehdr, &shdr, sec, NULL);246 247elf_out:248 elf_end(elf);249out:250 close(fd);251 return found;252}253 254static int elf_read_program_header(Elf *elf, u64 vaddr, GElf_Phdr *phdr)255{256 size_t i, phdrnum;257 u64 sz;258 259 if (elf_getphdrnum(elf, &phdrnum))260 return -1;261 262 for (i = 0; i < phdrnum; i++) {263 if (gelf_getphdr(elf, i, phdr) == NULL)264 return -1;265 266 if (phdr->p_type != PT_LOAD)267 continue;268 269 sz = max(phdr->p_memsz, phdr->p_filesz);270 if (!sz)271 continue;272 273 if (vaddr >= phdr->p_vaddr && (vaddr < phdr->p_vaddr + sz))274 return 0;275 }276 277 /* Not found any valid program header */278 return -1;279}280 281static bool want_demangle(bool is_kernel_sym)282{283 return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;284}285 286/*287 * Demangle C++ function signature, typically replaced by demangle-cxx.cpp288 * version.289 */290__weak char *cxx_demangle_sym(const char *str __maybe_unused, bool params __maybe_unused,291 bool modifiers __maybe_unused)292{293#ifdef HAVE_LIBBFD_SUPPORT294 int flags = (params ? DMGL_PARAMS : 0) | (modifiers ? DMGL_ANSI : 0);295 296 return bfd_demangle(NULL, str, flags);297#elif defined(HAVE_CPLUS_DEMANGLE_SUPPORT)298 int flags = (params ? DMGL_PARAMS : 0) | (modifiers ? DMGL_ANSI : 0);299 300 return cplus_demangle(str, flags);301#else302 return NULL;303#endif304}305 306static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)307{308 char *demangled = NULL;309 310 /*311 * We need to figure out if the object was created from C++ sources312 * DWARF DW_compile_unit has this, but we don't always have access313 * to it...314 */315 if (!want_demangle(dso__kernel(dso) || kmodule))316 return demangled;317 318 demangled = cxx_demangle_sym(elf_name, verbose > 0, verbose > 0);319 if (demangled == NULL) {320 demangled = ocaml_demangle_sym(elf_name);321 if (demangled == NULL) {322 demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);323 }324 }325 else if (rust_is_mangled(demangled))326 /*327 * Input to Rust demangling is the BFD-demangled328 * name which it Rust-demangles in place.329 */330 rust_demangle_sym(demangled);331 332 return demangled;333}334 335struct rel_info {336 u32 nr_entries;337 u32 *sorted;338 bool is_rela;339 Elf_Data *reldata;340 GElf_Rela rela;341 GElf_Rel rel;342};343 344static u32 get_rel_symidx(struct rel_info *ri, u32 idx)345{346 idx = ri->sorted ? ri->sorted[idx] : idx;347 if (ri->is_rela) {348 gelf_getrela(ri->reldata, idx, &ri->rela);349 return GELF_R_SYM(ri->rela.r_info);350 }351 gelf_getrel(ri->reldata, idx, &ri->rel);352 return GELF_R_SYM(ri->rel.r_info);353}354 355static u64 get_rel_offset(struct rel_info *ri, u32 x)356{357 if (ri->is_rela) {358 GElf_Rela rela;359 360 gelf_getrela(ri->reldata, x, &rela);361 return rela.r_offset;362 } else {363 GElf_Rel rel;364 365 gelf_getrel(ri->reldata, x, &rel);366 return rel.r_offset;367 }368}369 370static int rel_cmp(const void *a, const void *b, void *r)371{372 struct rel_info *ri = r;373 u64 a_offset = get_rel_offset(ri, *(const u32 *)a);374 u64 b_offset = get_rel_offset(ri, *(const u32 *)b);375 376 return a_offset < b_offset ? -1 : (a_offset > b_offset ? 1 : 0);377}378 379static int sort_rel(struct rel_info *ri)380{381 size_t sz = sizeof(ri->sorted[0]);382 u32 i;383 384 ri->sorted = calloc(ri->nr_entries, sz);385 if (!ri->sorted)386 return -1;387 for (i = 0; i < ri->nr_entries; i++)388 ri->sorted[i] = i;389 qsort_r(ri->sorted, ri->nr_entries, sz, rel_cmp, ri);390 return 0;391}392 393/*394 * For x86_64, the GNU linker is putting IFUNC information in the relocation395 * addend.396 */397static bool addend_may_be_ifunc(GElf_Ehdr *ehdr, struct rel_info *ri)398{399 return ehdr->e_machine == EM_X86_64 && ri->is_rela &&400 GELF_R_TYPE(ri->rela.r_info) == R_X86_64_IRELATIVE;401}402 403static bool get_ifunc_name(Elf *elf, struct dso *dso, GElf_Ehdr *ehdr,404 struct rel_info *ri, char *buf, size_t buf_sz)405{406 u64 addr = ri->rela.r_addend;407 struct symbol *sym;408 GElf_Phdr phdr;409 410 if (!addend_may_be_ifunc(ehdr, ri))411 return false;412 413 if (elf_read_program_header(elf, addr, &phdr))414 return false;415 416 addr -= phdr.p_vaddr - phdr.p_offset;417 418 sym = dso__find_symbol_nocache(dso, addr);419 420 /* Expecting the address to be an IFUNC or IFUNC alias */421 if (!sym || sym->start != addr || (sym->type != STT_GNU_IFUNC && !sym->ifunc_alias))422 return false;423 424 snprintf(buf, buf_sz, "%s@plt", sym->name);425 426 return true;427}428 429static void exit_rel(struct rel_info *ri)430{431 zfree(&ri->sorted);432}433 434static bool get_plt_sizes(struct dso *dso, GElf_Ehdr *ehdr, GElf_Shdr *shdr_plt,435 u64 *plt_header_size, u64 *plt_entry_size)436{437 switch (ehdr->e_machine) {438 case EM_ARM:439 *plt_header_size = 20;440 *plt_entry_size = 12;441 return true;442 case EM_AARCH64:443 *plt_header_size = 32;444 *plt_entry_size = 16;445 return true;446 case EM_LOONGARCH:447 *plt_header_size = 32;448 *plt_entry_size = 16;449 return true;450 case EM_SPARC:451 *plt_header_size = 48;452 *plt_entry_size = 12;453 return true;454 case EM_SPARCV9:455 *plt_header_size = 128;456 *plt_entry_size = 32;457 return true;458 case EM_386:459 case EM_X86_64:460 *plt_entry_size = shdr_plt->sh_entsize;461 /* Size is 8 or 16, if not, assume alignment indicates size */462 if (*plt_entry_size != 8 && *plt_entry_size != 16)463 *plt_entry_size = shdr_plt->sh_addralign == 8 ? 8 : 16;464 *plt_header_size = *plt_entry_size;465 break;466 default: /* FIXME: s390/alpha/mips/parisc/poperpc/sh/xtensa need to be checked */467 *plt_header_size = shdr_plt->sh_entsize;468 *plt_entry_size = shdr_plt->sh_entsize;469 break;470 }471 if (*plt_entry_size)472 return true;473 pr_debug("Missing PLT entry size for %s\n", dso__long_name(dso));474 return false;475}476 477static bool machine_is_x86(GElf_Half e_machine)478{479 return e_machine == EM_386 || e_machine == EM_X86_64;480}481 482struct rela_dyn {483 GElf_Addr offset;484 u32 sym_idx;485};486 487struct rela_dyn_info {488 struct dso *dso;489 Elf_Data *plt_got_data;490 u32 nr_entries;491 struct rela_dyn *sorted;492 Elf_Data *dynsym_data;493 Elf_Data *dynstr_data;494 Elf_Data *rela_dyn_data;495};496 497static void exit_rela_dyn(struct rela_dyn_info *di)498{499 zfree(&di->sorted);500}501 502static int cmp_offset(const void *a, const void *b)503{504 const struct rela_dyn *va = a;505 const struct rela_dyn *vb = b;506 507 return va->offset < vb->offset ? -1 : (va->offset > vb->offset ? 1 : 0);508}509 510static int sort_rela_dyn(struct rela_dyn_info *di)511{512 u32 i, n;513 514 di->sorted = calloc(di->nr_entries, sizeof(di->sorted[0]));515 if (!di->sorted)516 return -1;517 518 /* Get data for sorting: the offset and symbol index */519 for (i = 0, n = 0; i < di->nr_entries; i++) {520 GElf_Rela rela;521 u32 sym_idx;522 523 gelf_getrela(di->rela_dyn_data, i, &rela);524 sym_idx = GELF_R_SYM(rela.r_info);525 if (sym_idx) {526 di->sorted[n].sym_idx = sym_idx;527 di->sorted[n].offset = rela.r_offset;528 n += 1;529 }530 }531 532 /* Sort by offset */533 di->nr_entries = n;534 qsort(di->sorted, n, sizeof(di->sorted[0]), cmp_offset);535 536 return 0;537}538 539static void get_rela_dyn_info(Elf *elf, GElf_Ehdr *ehdr, struct rela_dyn_info *di, Elf_Scn *scn)540{541 GElf_Shdr rela_dyn_shdr;542 GElf_Shdr shdr;543 544 di->plt_got_data = elf_getdata(scn, NULL);545 546 scn = elf_section_by_name(elf, ehdr, &rela_dyn_shdr, ".rela.dyn", NULL);547 if (!scn || !rela_dyn_shdr.sh_link || !rela_dyn_shdr.sh_entsize)548 return;549 550 di->nr_entries = rela_dyn_shdr.sh_size / rela_dyn_shdr.sh_entsize;551 di->rela_dyn_data = elf_getdata(scn, NULL);552 553 scn = elf_getscn(elf, rela_dyn_shdr.sh_link);554 if (!scn || !gelf_getshdr(scn, &shdr) || !shdr.sh_link)555 return;556 557 di->dynsym_data = elf_getdata(scn, NULL);558 di->dynstr_data = elf_getdata(elf_getscn(elf, shdr.sh_link), NULL);559 560 if (!di->plt_got_data || !di->dynstr_data || !di->dynsym_data || !di->rela_dyn_data)561 return;562 563 /* Sort into offset order */564 sort_rela_dyn(di);565}566 567/* Get instruction displacement from a plt entry for x86_64 */568static u32 get_x86_64_plt_disp(const u8 *p)569{570 u8 endbr64[] = {0xf3, 0x0f, 0x1e, 0xfa};571 int n = 0;572 573 /* Skip endbr64 */574 if (!memcmp(p, endbr64, sizeof(endbr64)))575 n += sizeof(endbr64);576 /* Skip bnd prefix */577 if (p[n] == 0xf2)578 n += 1;579 /* jmp with 4-byte displacement */580 if (p[n] == 0xff && p[n + 1] == 0x25) {581 u32 disp;582 583 n += 2;584 /* Also add offset from start of entry to end of instruction */585 memcpy(&disp, p + n, sizeof(disp));586 return n + 4 + le32toh(disp);587 }588 return 0;589}590 591static bool get_plt_got_name(GElf_Shdr *shdr, size_t i,592 struct rela_dyn_info *di,593 char *buf, size_t buf_sz)594{595 struct rela_dyn vi, *vr;596 const char *sym_name;597 char *demangled;598 GElf_Sym sym;599 bool result;600 u32 disp;601 602 if (!di->sorted)603 return false;604 605 disp = get_x86_64_plt_disp(di->plt_got_data->d_buf + i);606 if (!disp)607 return false;608 609 /* Compute target offset of the .plt.got entry */610 vi.offset = shdr->sh_offset + di->plt_got_data->d_off + i + disp;611 612 /* Find that offset in .rela.dyn (sorted by offset) */613 vr = bsearch(&vi, di->sorted, di->nr_entries, sizeof(di->sorted[0]), cmp_offset);614 if (!vr)615 return false;616 617 /* Get the associated symbol */618 gelf_getsym(di->dynsym_data, vr->sym_idx, &sym);619 sym_name = elf_sym__name(&sym, di->dynstr_data);620 demangled = demangle_sym(di->dso, 0, sym_name);621 if (demangled != NULL)622 sym_name = demangled;623 624 snprintf(buf, buf_sz, "%s@plt", sym_name);625 626 result = *sym_name;627 628 free(demangled);629 630 return result;631}632 633static int dso__synthesize_plt_got_symbols(struct dso *dso, Elf *elf,634 GElf_Ehdr *ehdr,635 char *buf, size_t buf_sz)636{637 struct rela_dyn_info di = { .dso = dso };638 struct symbol *sym;639 GElf_Shdr shdr;640 Elf_Scn *scn;641 int err = -1;642 size_t i;643 644 scn = elf_section_by_name(elf, ehdr, &shdr, ".plt.got", NULL);645 if (!scn || !shdr.sh_entsize)646 return 0;647 648 if (ehdr->e_machine == EM_X86_64)649 get_rela_dyn_info(elf, ehdr, &di, scn);650 651 for (i = 0; i < shdr.sh_size; i += shdr.sh_entsize) {652 if (!get_plt_got_name(&shdr, i, &di, buf, buf_sz))653 snprintf(buf, buf_sz, "offset_%#" PRIx64 "@plt", (u64)shdr.sh_offset + i);654 sym = symbol__new(shdr.sh_offset + i, shdr.sh_entsize, STB_GLOBAL, STT_FUNC, buf);655 if (!sym)656 goto out;657 symbols__insert(dso__symbols(dso), sym);658 }659 err = 0;660out:661 exit_rela_dyn(&di);662 return err;663}664 665/*666 * We need to check if we have a .dynsym, so that we can handle the667 * .plt, synthesizing its symbols, that aren't on the symtabs (be it668 * .dynsym or .symtab).669 * And always look at the original dso, not at debuginfo packages, that670 * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).671 */672int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss)673{674 uint32_t idx;675 GElf_Sym sym;676 u64 plt_offset, plt_header_size, plt_entry_size;677 GElf_Shdr shdr_plt, plt_sec_shdr;678 struct symbol *f, *plt_sym;679 GElf_Shdr shdr_rel_plt, shdr_dynsym;680 Elf_Data *syms, *symstrs;681 Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;682 GElf_Ehdr ehdr;683 char sympltname[1024];684 Elf *elf;685 int nr = 0, err = -1;686 struct rel_info ri = { .is_rela = false };687 bool lazy_plt;688 689 elf = ss->elf;690 ehdr = ss->ehdr;691 692 if (!elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL))693 return 0;694 695 /*696 * A symbol from a previous section (e.g. .init) can have been expanded697 * by symbols__fixup_end() to overlap .plt. Truncate it before adding698 * a symbol for .plt header.699 */700 f = dso__find_symbol_nocache(dso, shdr_plt.sh_offset);701 if (f && f->start < shdr_plt.sh_offset && f->end > shdr_plt.sh_offset)702 f->end = shdr_plt.sh_offset;703 704 if (!get_plt_sizes(dso, &ehdr, &shdr_plt, &plt_header_size, &plt_entry_size))705 return 0;706 707 /* Add a symbol for .plt header */708 plt_sym = symbol__new(shdr_plt.sh_offset, plt_header_size, STB_GLOBAL, STT_FUNC, ".plt");709 if (!plt_sym)710 goto out_elf_end;711 symbols__insert(dso__symbols(dso), plt_sym);712 713 /* Only x86 has .plt.got */714 if (machine_is_x86(ehdr.e_machine) &&715 dso__synthesize_plt_got_symbols(dso, elf, &ehdr, sympltname, sizeof(sympltname)))716 goto out_elf_end;717 718 /* Only x86 has .plt.sec */719 if (machine_is_x86(ehdr.e_machine) &&720 elf_section_by_name(elf, &ehdr, &plt_sec_shdr, ".plt.sec", NULL)) {721 if (!get_plt_sizes(dso, &ehdr, &plt_sec_shdr, &plt_header_size, &plt_entry_size))722 return 0;723 /* Extend .plt symbol to entire .plt */724 plt_sym->end = plt_sym->start + shdr_plt.sh_size;725 /* Use .plt.sec offset */726 plt_offset = plt_sec_shdr.sh_offset;727 lazy_plt = false;728 } else {729 plt_offset = shdr_plt.sh_offset;730 lazy_plt = true;731 }732 733 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,734 ".rela.plt", NULL);735 if (scn_plt_rel == NULL) {736 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,737 ".rel.plt", NULL);738 if (scn_plt_rel == NULL)739 return 0;740 }741 742 if (shdr_rel_plt.sh_type != SHT_RELA &&743 shdr_rel_plt.sh_type != SHT_REL)744 return 0;745 746 if (!shdr_rel_plt.sh_link)747 return 0;748 749 if (shdr_rel_plt.sh_link == ss->dynsym_idx) {750 scn_dynsym = ss->dynsym;751 shdr_dynsym = ss->dynshdr;752 } else if (shdr_rel_plt.sh_link == ss->symtab_idx) {753 /*754 * A static executable can have a .plt due to IFUNCs, in which755 * case .symtab is used not .dynsym.756 */757 scn_dynsym = ss->symtab;758 shdr_dynsym = ss->symshdr;759 } else {760 goto out_elf_end;761 }762 763 if (!scn_dynsym)764 return 0;765 766 /*767 * Fetch the relocation section to find the idxes to the GOT768 * and the symbols in the .dynsym they refer to.769 */770 ri.reldata = elf_getdata(scn_plt_rel, NULL);771 if (!ri.reldata)772 goto out_elf_end;773 774 syms = elf_getdata(scn_dynsym, NULL);775 if (syms == NULL)776 goto out_elf_end;777 778 scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);779 if (scn_symstrs == NULL)780 goto out_elf_end;781 782 symstrs = elf_getdata(scn_symstrs, NULL);783 if (symstrs == NULL)784 goto out_elf_end;785 786 if (symstrs->d_size == 0)787 goto out_elf_end;788 789 ri.nr_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;790 791 ri.is_rela = shdr_rel_plt.sh_type == SHT_RELA;792 793 if (lazy_plt) {794 /*795 * Assume a .plt with the same number of entries as the number796 * of relocation entries is not lazy and does not have a header.797 */798 if (ri.nr_entries * plt_entry_size == shdr_plt.sh_size)799 dso__delete_symbol(dso, plt_sym);800 else801 plt_offset += plt_header_size;802 }803 804 /*805 * x86 doesn't insert IFUNC relocations in .plt order, so sort to get806 * back in order.807 */808 if (machine_is_x86(ehdr.e_machine) && sort_rel(&ri))809 goto out_elf_end;810 811 for (idx = 0; idx < ri.nr_entries; idx++) {812 const char *elf_name = NULL;813 char *demangled = NULL;814 815 gelf_getsym(syms, get_rel_symidx(&ri, idx), &sym);816 817 elf_name = elf_sym__name(&sym, symstrs);818 demangled = demangle_sym(dso, 0, elf_name);819 if (demangled)820 elf_name = demangled;821 if (*elf_name)822 snprintf(sympltname, sizeof(sympltname), "%s@plt", elf_name);823 else if (!get_ifunc_name(elf, dso, &ehdr, &ri, sympltname, sizeof(sympltname)))824 snprintf(sympltname, sizeof(sympltname),825 "offset_%#" PRIx64 "@plt", plt_offset);826 free(demangled);827 828 f = symbol__new(plt_offset, plt_entry_size, STB_GLOBAL, STT_FUNC, sympltname);829 if (!f)830 goto out_elf_end;831 832 plt_offset += plt_entry_size;833 symbols__insert(dso__symbols(dso), f);834 ++nr;835 }836 837 err = 0;838out_elf_end:839 exit_rel(&ri);840 if (err == 0)841 return nr;842 pr_debug("%s: problems reading %s PLT info.\n",843 __func__, dso__long_name(dso));844 return 0;845}846 847char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name)848{849 return demangle_sym(dso, kmodule, elf_name);850}851 852/*853 * Align offset to 4 bytes as needed for note name and descriptor data.854 */855#define NOTE_ALIGN(n) (((n) + 3) & -4U)856 857static int elf_read_build_id(Elf *elf, void *bf, size_t size)858{859 int err = -1;860 GElf_Ehdr ehdr;861 GElf_Shdr shdr;862 Elf_Data *data;863 Elf_Scn *sec;864 Elf_Kind ek;865 void *ptr;866 867 if (size < BUILD_ID_SIZE)868 goto out;869 870 ek = elf_kind(elf);871 if (ek != ELF_K_ELF)872 goto out;873 874 if (gelf_getehdr(elf, &ehdr) == NULL) {875 pr_err("%s: cannot get elf header.\n", __func__);876 goto out;877 }878 879 /*880 * Check following sections for notes:881 * '.note.gnu.build-id'882 * '.notes'883 * '.note' (VDSO specific)884 */885 do {886 sec = elf_section_by_name(elf, &ehdr, &shdr,887 ".note.gnu.build-id", NULL);888 if (sec)889 break;890 891 sec = elf_section_by_name(elf, &ehdr, &shdr,892 ".notes", NULL);893 if (sec)894 break;895 896 sec = elf_section_by_name(elf, &ehdr, &shdr,897 ".note", NULL);898 if (sec)899 break;900 901 return err;902 903 } while (0);904 905 data = elf_getdata(sec, NULL);906 if (data == NULL)907 goto out;908 909 ptr = data->d_buf;910 while (ptr < (data->d_buf + data->d_size)) {911 GElf_Nhdr *nhdr = ptr;912 size_t namesz = NOTE_ALIGN(nhdr->n_namesz),913 descsz = NOTE_ALIGN(nhdr->n_descsz);914 const char *name;915 916 ptr += sizeof(*nhdr);917 name = ptr;918 ptr += namesz;919 if (nhdr->n_type == NT_GNU_BUILD_ID &&920 nhdr->n_namesz == sizeof("GNU")) {921 if (memcmp(name, "GNU", sizeof("GNU")) == 0) {922 size_t sz = min(size, descsz);923 memcpy(bf, ptr, sz);924 memset(bf + sz, 0, size - sz);925 err = sz;926 break;927 }928 }929 ptr += descsz;930 }931 932out:933 return err;934}935 936#ifdef HAVE_LIBBFD_BUILDID_SUPPORT937 938static int read_build_id(const char *filename, struct build_id *bid)939{940 size_t size = sizeof(bid->data);941 int err = -1;942 bfd *abfd;943 944 abfd = bfd_openr(filename, NULL);945 if (!abfd)946 return -1;947 948 if (!bfd_check_format(abfd, bfd_object)) {949 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);950 goto out_close;951 }952 953 if (!abfd->build_id || abfd->build_id->size > size)954 goto out_close;955 956 memcpy(bid->data, abfd->build_id->data, abfd->build_id->size);957 memset(bid->data + abfd->build_id->size, 0, size - abfd->build_id->size);958 err = bid->size = abfd->build_id->size;959 960out_close:961 bfd_close(abfd);962 return err;963}964 965#else // HAVE_LIBBFD_BUILDID_SUPPORT966 967static int read_build_id(const char *filename, struct build_id *bid)968{969 size_t size = sizeof(bid->data);970 int fd, err = -1;971 Elf *elf;972 973 if (size < BUILD_ID_SIZE)974 goto out;975 976 fd = open(filename, O_RDONLY);977 if (fd < 0)978 goto out;979 980 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);981 if (elf == NULL) {982 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);983 goto out_close;984 }985 986 err = elf_read_build_id(elf, bid->data, size);987 if (err > 0)988 bid->size = err;989 990 elf_end(elf);991out_close:992 close(fd);993out:994 return err;995}996 997#endif // HAVE_LIBBFD_BUILDID_SUPPORT998 999int filename__read_build_id(const char *filename, struct build_id *bid)1000{1001 struct kmod_path m = { .name = NULL, };1002 char path[PATH_MAX];1003 int err;1004 1005 if (!filename)1006 return -EFAULT;1007 1008 err = kmod_path__parse(&m, filename);1009 if (err)1010 return -1;1011 1012 if (m.comp) {1013 int error = 0, fd;1014 1015 fd = filename__decompress(filename, path, sizeof(path), m.comp, &error);1016 if (fd < 0) {1017 pr_debug("Failed to decompress (error %d) %s\n",1018 error, filename);1019 return -1;1020 }1021 close(fd);1022 filename = path;1023 }1024 1025 err = read_build_id(filename, bid);1026 1027 if (m.comp)1028 unlink(filename);1029 return err;1030}1031 1032int sysfs__read_build_id(const char *filename, struct build_id *bid)1033{1034 size_t size = sizeof(bid->data);1035 int fd, err = -1;1036 1037 fd = open(filename, O_RDONLY);1038 if (fd < 0)1039 goto out;1040 1041 while (1) {1042 char bf[BUFSIZ];1043 GElf_Nhdr nhdr;1044 size_t namesz, descsz;1045 1046 if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))1047 break;1048 1049 namesz = NOTE_ALIGN(nhdr.n_namesz);1050 descsz = NOTE_ALIGN(nhdr.n_descsz);1051 if (nhdr.n_type == NT_GNU_BUILD_ID &&1052 nhdr.n_namesz == sizeof("GNU")) {1053 if (read(fd, bf, namesz) != (ssize_t)namesz)1054 break;1055 if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {1056 size_t sz = min(descsz, size);1057 if (read(fd, bid->data, sz) == (ssize_t)sz) {1058 memset(bid->data + sz, 0, size - sz);1059 bid->size = sz;1060 err = 0;1061 break;1062 }1063 } else if (read(fd, bf, descsz) != (ssize_t)descsz)1064 break;1065 } else {1066 int n = namesz + descsz;1067 1068 if (n > (int)sizeof(bf)) {1069 n = sizeof(bf);1070 pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",1071 __func__, filename, nhdr.n_namesz, nhdr.n_descsz);1072 }1073 if (read(fd, bf, n) != n)1074 break;1075 }1076 }1077 close(fd);1078out:1079 return err;1080}1081 1082#ifdef HAVE_LIBBFD_SUPPORT1083 1084int filename__read_debuglink(const char *filename, char *debuglink,1085 size_t size)1086{1087 int err = -1;1088 asection *section;1089 bfd *abfd;1090 1091 abfd = bfd_openr(filename, NULL);1092 if (!abfd)1093 return -1;1094 1095 if (!bfd_check_format(abfd, bfd_object)) {1096 pr_debug2("%s: cannot read %s bfd file.\n", __func__, filename);1097 goto out_close;1098 }1099 1100 section = bfd_get_section_by_name(abfd, ".gnu_debuglink");1101 if (!section)1102 goto out_close;1103 1104 if (section->size > size)1105 goto out_close;1106 1107 if (!bfd_get_section_contents(abfd, section, debuglink, 0,1108 section->size))1109 goto out_close;1110 1111 err = 0;1112 1113out_close:1114 bfd_close(abfd);1115 return err;1116}1117 1118#else1119 1120int filename__read_debuglink(const char *filename, char *debuglink,1121 size_t size)1122{1123 int fd, err = -1;1124 Elf *elf;1125 GElf_Ehdr ehdr;1126 GElf_Shdr shdr;1127 Elf_Data *data;1128 Elf_Scn *sec;1129 Elf_Kind ek;1130 1131 fd = open(filename, O_RDONLY);1132 if (fd < 0)1133 goto out;1134 1135 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);1136 if (elf == NULL) {1137 pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);1138 goto out_close;1139 }1140 1141 ek = elf_kind(elf);1142 if (ek != ELF_K_ELF)1143 goto out_elf_end;1144 1145 if (gelf_getehdr(elf, &ehdr) == NULL) {1146 pr_err("%s: cannot get elf header.\n", __func__);1147 goto out_elf_end;1148 }1149 1150 sec = elf_section_by_name(elf, &ehdr, &shdr,1151 ".gnu_debuglink", NULL);1152 if (sec == NULL)1153 goto out_elf_end;1154 1155 data = elf_getdata(sec, NULL);1156 if (data == NULL)1157 goto out_elf_end;1158 1159 /* the start of this section is a zero-terminated string */1160 strncpy(debuglink, data->d_buf, size);1161 1162 err = 0;1163 1164out_elf_end:1165 elf_end(elf);1166out_close:1167 close(fd);1168out:1169 return err;1170}1171 1172#endif1173 1174static int dso__swap_init(struct dso *dso, unsigned char eidata)1175{1176 static unsigned int const endian = 1;1177 1178 dso__set_needs_swap(dso, DSO_SWAP__NO);1179 1180 switch (eidata) {1181 case ELFDATA2LSB:1182 /* We are big endian, DSO is little endian. */1183 if (*(unsigned char const *)&endian != 1)1184 dso__set_needs_swap(dso, DSO_SWAP__YES);1185 break;1186 1187 case ELFDATA2MSB:1188 /* We are little endian, DSO is big endian. */1189 if (*(unsigned char const *)&endian != 0)1190 dso__set_needs_swap(dso, DSO_SWAP__YES);1191 break;1192 1193 default:1194 pr_err("unrecognized DSO data encoding %d\n", eidata);1195 return -EINVAL;1196 }1197 1198 return 0;1199}1200 1201bool symsrc__possibly_runtime(struct symsrc *ss)1202{1203 return ss->dynsym || ss->opdsec;1204}1205 1206bool symsrc__has_symtab(struct symsrc *ss)1207{1208 return ss->symtab != NULL;1209}1210 1211void symsrc__destroy(struct symsrc *ss)1212{1213 zfree(&ss->name);1214 elf_end(ss->elf);1215 close(ss->fd);1216}1217 1218bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)1219{1220 /*1221 * Usually vmlinux is an ELF file with type ET_EXEC for most1222 * architectures; except Arm64 kernel is linked with option1223 * '-share', so need to check type ET_DYN.1224 */1225 return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL ||1226 ehdr.e_type == ET_DYN;1227}1228 1229int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,1230 enum dso_binary_type type)1231{1232 GElf_Ehdr ehdr;1233 Elf *elf;1234 int fd;1235 1236 if (dso__needs_decompress(dso)) {1237 fd = dso__decompress_kmodule_fd(dso, name);1238 if (fd < 0)1239 return -1;1240 1241 type = dso__symtab_type(dso);1242 } else {1243 fd = open(name, O_RDONLY);1244 if (fd < 0) {1245 *dso__load_errno(dso) = errno;1246 return -1;1247 }1248 }1249 1250 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);1251 if (elf == NULL) {1252 pr_debug("%s: cannot read %s ELF file.\n", __func__, name);1253 *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;1254 goto out_close;1255 }1256 1257 if (gelf_getehdr(elf, &ehdr) == NULL) {1258 *dso__load_errno(dso) = DSO_LOAD_ERRNO__INVALID_ELF;1259 pr_debug("%s: cannot get elf header.\n", __func__);1260 goto out_elf_end;1261 }1262 1263 if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {1264 *dso__load_errno(dso) = DSO_LOAD_ERRNO__INTERNAL_ERROR;1265 goto out_elf_end;1266 }1267 1268 /* Always reject images with a mismatched build-id: */1269 if (dso__has_build_id(dso) && !symbol_conf.ignore_vmlinux_buildid) {1270 u8 build_id[BUILD_ID_SIZE];1271 struct build_id bid;1272 int size;1273 1274 size = elf_read_build_id(elf, build_id, BUILD_ID_SIZE);1275 if (size <= 0) {1276 *dso__load_errno(dso) = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;1277 goto out_elf_end;1278 }1279 1280 build_id__init(&bid, build_id, size);1281 if (!dso__build_id_equal(dso, &bid)) {1282 pr_debug("%s: build id mismatch for %s.\n", __func__, name);1283 *dso__load_errno(dso) = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;1284 goto out_elf_end;1285 }1286 }1287 1288 ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);1289 1290 ss->symtab_idx = 0;1291 ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",1292 &ss->symtab_idx);1293 if (ss->symshdr.sh_type != SHT_SYMTAB)1294 ss->symtab = NULL;1295 1296 ss->dynsym_idx = 0;1297 ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",1298 &ss->dynsym_idx);1299 if (ss->dynshdr.sh_type != SHT_DYNSYM)1300 ss->dynsym = NULL;1301 1302 ss->opdidx = 0;1303 ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",1304 &ss->opdidx);1305 if (ss->opdshdr.sh_type != SHT_PROGBITS)1306 ss->opdsec = NULL;1307 1308 if (dso__kernel(dso) == DSO_SPACE__USER)1309 ss->adjust_symbols = true;1310 else1311 ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);1312 1313 ss->name = strdup(name);1314 if (!ss->name) {1315 *dso__load_errno(dso) = errno;1316 goto out_elf_end;1317 }1318 1319 ss->elf = elf;1320 ss->fd = fd;1321 ss->ehdr = ehdr;1322 ss->type = type;1323 1324 return 0;1325 1326out_elf_end:1327 elf_end(elf);1328out_close:1329 close(fd);1330 return -1;1331}1332 1333static bool is_exe_text(int flags)1334{1335 return (flags & (SHF_ALLOC | SHF_EXECINSTR)) == (SHF_ALLOC | SHF_EXECINSTR);1336}1337 1338/*1339 * Some executable module sections like .noinstr.text might be laid out with1340 * .text so they can use the same mapping (memory address to file offset).1341 * Check if that is the case. Refer to kernel layout_sections(). Return the1342 * maximum offset.1343 */1344static u64 max_text_section(Elf *elf, GElf_Ehdr *ehdr)1345{1346 Elf_Scn *sec = NULL;1347 GElf_Shdr shdr;1348 u64 offs = 0;1349 1350 /* Doesn't work for some arch */1351 if (ehdr->e_machine == EM_PARISC ||1352 ehdr->e_machine == EM_ALPHA)1353 return 0;1354 1355 /* ELF is corrupted/truncated, avoid calling elf_strptr. */1356 if (!elf_rawdata(elf_getscn(elf, ehdr->e_shstrndx), NULL))1357 return 0;1358 1359 while ((sec = elf_nextscn(elf, sec)) != NULL) {1360 char *sec_name;1361 1362 if (!gelf_getshdr(sec, &shdr))1363 break;1364 1365 if (!is_exe_text(shdr.sh_flags))1366 continue;1367 1368 /* .init and .exit sections are not placed with .text */1369 sec_name = elf_strptr(elf, ehdr->e_shstrndx, shdr.sh_name);1370 if (!sec_name ||1371 strstarts(sec_name, ".init") ||1372 strstarts(sec_name, ".exit"))1373 break;1374 1375 /* Must be next to previous, assumes .text is first */1376 if (offs && PERF_ALIGN(offs, shdr.sh_addralign ?: 1) != shdr.sh_offset)1377 break;1378 1379 offs = shdr.sh_offset + shdr.sh_size;1380 }1381 1382 return offs;1383}1384 1385/**1386 * ref_reloc_sym_not_found - has kernel relocation symbol been found.1387 * @kmap: kernel maps and relocation reference symbol1388 *1389 * This function returns %true if we are dealing with the kernel maps and the1390 * relocation reference symbol has not yet been found. Otherwise %false is1391 * returned.1392 */1393static bool ref_reloc_sym_not_found(struct kmap *kmap)1394{1395 return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&1396 !kmap->ref_reloc_sym->unrelocated_addr;1397}1398 1399/**1400 * ref_reloc - kernel relocation offset.1401 * @kmap: kernel maps and relocation reference symbol1402 *1403 * This function returns the offset of kernel addresses as determined by using1404 * the relocation reference symbol i.e. if the kernel has not been relocated1405 * then the return value is zero.1406 */1407static u64 ref_reloc(struct kmap *kmap)1408{1409 if (kmap && kmap->ref_reloc_sym &&1410 kmap->ref_reloc_sym->unrelocated_addr)1411 return kmap->ref_reloc_sym->addr -1412 kmap->ref_reloc_sym->unrelocated_addr;1413 return 0;1414}1415 1416void __weak arch__sym_update(struct symbol *s __maybe_unused,1417 GElf_Sym *sym __maybe_unused) { }1418 1419static int dso__process_kernel_symbol(struct dso *dso, struct map *map,1420 GElf_Sym *sym, GElf_Shdr *shdr,1421 struct maps *kmaps, struct kmap *kmap,1422 struct dso **curr_dsop,1423 const char *section_name,1424 bool adjust_kernel_syms, bool kmodule, bool *remap_kernel,1425 u64 max_text_sh_offset)1426{1427 struct dso *curr_dso = *curr_dsop;1428 struct map *curr_map;1429 char dso_name[PATH_MAX];1430 1431 /* Adjust symbol to map to file offset */1432 if (adjust_kernel_syms)1433 sym->st_value -= shdr->sh_addr - shdr->sh_offset;1434 1435 if (strcmp(section_name, (dso__short_name(curr_dso) + dso__short_name_len(dso))) == 0)1436 return 0;1437 1438 if (strcmp(section_name, ".text") == 0) {1439 /*1440 * The initial kernel mapping is based on1441 * kallsyms and identity maps. Overwrite it to1442 * map to the kernel dso.1443 */1444 if (*remap_kernel && dso__kernel(dso) && !kmodule) {1445 *remap_kernel = false;1446 map__set_start(map, shdr->sh_addr + ref_reloc(kmap));1447 map__set_end(map, map__start(map) + shdr->sh_size);1448 map__set_pgoff(map, shdr->sh_offset);1449 map__set_mapping_type(map, MAPPING_TYPE__DSO);1450 /* Ensure maps are correctly ordered */1451 if (kmaps) {1452 int err;1453 struct map *tmp = map__get(map);1454 1455 maps__remove(kmaps, map);1456 err = maps__insert(kmaps, map);1457 map__put(tmp);1458 if (err)1459 return err;1460 }1461 }1462 1463 /*1464 * The initial module mapping is based on1465 * /proc/modules mapped to offset zero.1466 * Overwrite it to map to the module dso.1467 */1468 if (*remap_kernel && kmodule) {1469 *remap_kernel = false;1470 map__set_pgoff(map, shdr->sh_offset);1471 }1472 1473 dso__put(*curr_dsop);1474 *curr_dsop = dso__get(dso);1475 return 0;1476 }1477 1478 if (!kmap)1479 return 0;1480 1481 /*1482 * perf does not record module section addresses except for .text, but1483 * some sections can use the same mapping as .text.1484 */1485 if (kmodule && adjust_kernel_syms && is_exe_text(shdr->sh_flags) &&1486 shdr->sh_offset <= max_text_sh_offset) {1487 dso__put(*curr_dsop);1488 *curr_dsop = dso__get(dso);1489 return 0;1490 }1491 1492 snprintf(dso_name, sizeof(dso_name), "%s%s", dso__short_name(dso), section_name);1493 1494 curr_map = maps__find_by_name(kmaps, dso_name);1495 if (curr_map == NULL) {1496 u64 start = sym->st_value;1497 1498 if (kmodule)1499 start += map__start(map) + shdr->sh_offset;1500 1501 curr_dso = dso__new(dso_name);1502 if (curr_dso == NULL)1503 return -1;1504 dso__set_kernel(curr_dso, dso__kernel(dso));1505 RC_CHK_ACCESS(curr_dso)->long_name = dso__long_name(dso);1506 RC_CHK_ACCESS(curr_dso)->long_name_len = dso__long_name_len(dso);1507 dso__set_binary_type(curr_dso, dso__binary_type(dso));1508 dso__set_adjust_symbols(curr_dso, dso__adjust_symbols(dso));1509 curr_map = map__new2(start, curr_dso);1510 if (curr_map == NULL) {1511 dso__put(curr_dso);1512 return -1;1513 }1514 if (dso__kernel(curr_dso))1515 map__kmap(curr_map)->kmaps = kmaps;1516 1517 if (adjust_kernel_syms) {1518 map__set_start(curr_map, shdr->sh_addr + ref_reloc(kmap));1519 map__set_end(curr_map, map__start(curr_map) + shdr->sh_size);1520 map__set_pgoff(curr_map, shdr->sh_offset);1521 } else {1522 map__set_mapping_type(curr_map, MAPPING_TYPE__IDENTITY);1523 }1524 dso__set_symtab_type(curr_dso, dso__symtab_type(dso));1525 if (maps__insert(kmaps, curr_map))1526 return -1;1527 dsos__add(&maps__machine(kmaps)->dsos, curr_dso);1528 dso__set_loaded(curr_dso);1529 dso__put(*curr_dsop);1530 *curr_dsop = curr_dso;1531 } else {1532 dso__put(*curr_dsop);1533 *curr_dsop = dso__get(map__dso(curr_map));1534 }1535 map__put(curr_map);1536 1537 return 0;1538}1539 1540static int1541dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,1542 struct symsrc *runtime_ss, int kmodule, int dynsym)1543{1544 struct kmap *kmap = dso__kernel(dso) ? map__kmap(map) : NULL;1545 struct maps *kmaps = kmap ? map__kmaps(map) : NULL;1546 struct dso *curr_dso = NULL;1547 Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym;1548 uint32_t nr_syms;1549 uint32_t idx;1550 GElf_Ehdr ehdr;1551 GElf_Shdr shdr;1552 GElf_Shdr tshdr;1553 Elf_Data *syms, *opddata = NULL;1554 GElf_Sym sym;1555 Elf_Scn *sec, *sec_strndx;1556 Elf *elf;1557 int nr = 0;1558 bool remap_kernel = false, adjust_kernel_syms = false;1559 u64 max_text_sh_offset = 0;1560 1561 if (kmap && !kmaps)1562 return -1;1563 1564 elf = syms_ss->elf;1565 ehdr = syms_ss->ehdr;1566 if (dynsym) {1567 sec = syms_ss->dynsym;1568 shdr = syms_ss->dynshdr;1569 } else {1570 sec = syms_ss->symtab;1571 shdr = syms_ss->symshdr;1572 }1573 1574 if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,1575 ".text", NULL)) {1576 dso__set_text_offset(dso, tshdr.sh_addr - tshdr.sh_offset);1577 dso__set_text_end(dso, tshdr.sh_offset + tshdr.sh_size);1578 }1579 1580 if (runtime_ss->opdsec)1581 opddata = elf_rawdata(runtime_ss->opdsec, NULL);1582 1583 syms = elf_getdata(sec, NULL);1584 if (syms == NULL)1585 goto out_elf_end;1586 1587 sec = elf_getscn(elf, shdr.sh_link);1588 if (sec == NULL)1589 goto out_elf_end;1590 1591 symstrs = elf_getdata(sec, NULL);1592 if (symstrs == NULL)1593 goto out_elf_end;1594 1595 sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);1596 if (sec_strndx == NULL)1597 goto out_elf_end;1598 1599 secstrs_run = elf_getdata(sec_strndx, NULL);1600 if (secstrs_run == NULL)1601 goto out_elf_end;1602 1603 sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);1604 if (sec_strndx == NULL)1605 goto out_elf_end;1606 1607 secstrs_sym = elf_getdata(sec_strndx, NULL);1608 if (secstrs_sym == NULL)1609 goto out_elf_end;1610 1611 nr_syms = shdr.sh_size / shdr.sh_entsize;1612 1613 memset(&sym, 0, sizeof(sym));1614 1615 /*1616 * The kernel relocation symbol is needed in advance in order to adjust1617 * kernel maps correctly.1618 */1619 if (ref_reloc_sym_not_found(kmap)) {1620 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {1621 const char *elf_name = elf_sym__name(&sym, symstrs);1622 1623 if (strcmp(elf_name, kmap->ref_reloc_sym->name))1624 continue;1625 kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;1626 map__set_reloc(map, kmap->ref_reloc_sym->addr - kmap->ref_reloc_sym->unrelocated_addr);1627 break;1628 }1629 }1630 1631 /*1632 * Handle any relocation of vdso necessary because older kernels1633 * attempted to prelink vdso to its virtual address.1634 */1635 if (dso__is_vdso(dso))1636 map__set_reloc(map, map__start(map) - dso__text_offset(dso));1637 1638 dso__set_adjust_symbols(dso, runtime_ss->adjust_symbols || ref_reloc(kmap));1639 /*1640 * Initial kernel and module mappings do not map to the dso.1641 * Flag the fixups.1642 */1643 if (dso__kernel(dso)) {1644 remap_kernel = true;1645 adjust_kernel_syms = dso__adjust_symbols(dso);1646 }1647 1648 if (kmodule && adjust_kernel_syms)1649 max_text_sh_offset = max_text_section(runtime_ss->elf, &runtime_ss->ehdr);1650 1651 curr_dso = dso__get(dso);1652 elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {1653 struct symbol *f;1654 const char *elf_name = elf_sym__name(&sym, symstrs);1655 char *demangled = NULL;1656 int is_label = elf_sym__is_label(&sym);1657 const char *section_name;1658 bool used_opd = false;1659 1660 if (!is_label && !elf_sym__filter(&sym))1661 continue;1662 1663 /* Reject ARM ELF "mapping symbols": these aren't unique and1664 * don't identify functions, so will confuse the profile1665 * output: */1666 if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {1667 if (elf_name[0] == '$' && strchr("adtx", elf_name[1])1668 && (elf_name[2] == '\0' || elf_name[2] == '.'))1669 continue;1670 }1671 1672 if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {1673 u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;1674 u64 *opd = opddata->d_buf + offset;1675 sym.st_value = DSO__SWAP(dso, u64, *opd);1676 sym.st_shndx = elf_addr_to_index(runtime_ss->elf,1677 sym.st_value);1678 used_opd = true;1679 }1680 1681 /*1682 * When loading symbols in a data mapping, ABS symbols (which1683 * has a value of SHN_ABS in its st_shndx) failed at1684 * elf_getscn(). And it marks the loading as a failure so1685 * already loaded symbols cannot be fixed up.1686 *1687 * I'm not sure what should be done. Just ignore them for now.1688 * - Namhyung Kim1689 */1690 if (sym.st_shndx == SHN_ABS)1691 continue;1692 1693 sec = elf_getscn(syms_ss->elf, sym.st_shndx);1694 if (!sec)1695 goto out_elf_end;1696 1697 gelf_getshdr(sec, &shdr);1698 1699 /*1700 * If the attribute bit SHF_ALLOC is not set, the section1701 * doesn't occupy memory during process execution.1702 * E.g. ".gnu.warning.*" section is used by linker to generate1703 * warnings when calling deprecated functions, the symbols in1704 * the section aren't loaded to memory during process execution,1705 * so skip them.1706 */1707 if (!(shdr.sh_flags & SHF_ALLOC))1708 continue;1709 1710 secstrs = secstrs_sym;1711 1712 /*1713 * We have to fallback to runtime when syms' section header has1714 * NOBITS set. NOBITS results in file offset (sh_offset) not1715 * being incremented. So sh_offset used below has different1716 * values for syms (invalid) and runtime (valid).1717 */1718 if (shdr.sh_type == SHT_NOBITS) {1719 sec = elf_getscn(runtime_ss->elf, sym.st_shndx);1720 if (!sec)1721 goto out_elf_end;1722 1723 gelf_getshdr(sec, &shdr);1724 secstrs = secstrs_run;1725 }1726 1727 if (is_label && !elf_sec__filter(&shdr, secstrs))1728 continue;1729 1730 section_name = elf_sec__name(&shdr, secstrs);1731 1732 /* On ARM, symbols for thumb functions have 1 added to1733 * the symbol address as a flag - remove it */1734 if ((ehdr.e_machine == EM_ARM) &&1735 (GELF_ST_TYPE(sym.st_info) == STT_FUNC) &&1736 (sym.st_value & 1))1737 --sym.st_value;1738 1739 if (dso__kernel(dso)) {1740 if (dso__process_kernel_symbol(dso, map, &sym, &shdr,1741 kmaps, kmap, &curr_dso,1742 section_name,1743 adjust_kernel_syms,1744 kmodule,1745 &remap_kernel,1746 max_text_sh_offset))1747 goto out_elf_end;1748 } else if ((used_opd && runtime_ss->adjust_symbols) ||1749 (!used_opd && syms_ss->adjust_symbols)) {1750 GElf_Phdr phdr;1751 1752 if (elf_read_program_header(runtime_ss->elf,1753 (u64)sym.st_value, &phdr)) {1754 pr_debug4("%s: failed to find program header for "1755 "symbol: %s st_value: %#" PRIx64 "\n",1756 __func__, elf_name, (u64)sym.st_value);1757 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "1758 "sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n",1759 __func__, (u64)sym.st_value, (u64)shdr.sh_addr,1760 (u64)shdr.sh_offset);1761 /*1762 * Fail to find program header, let's rollback1763 * to use shdr.sh_addr and shdr.sh_offset to1764 * calibrate symbol's file address, though this1765 * is not necessary for normal C ELF file, we1766 * still need to handle java JIT symbols in this1767 * case.1768 */1769 sym.st_value -= shdr.sh_addr - shdr.sh_offset;1770 } else {1771 pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "1772 "p_vaddr: %#" PRIx64 " p_offset: %#" PRIx64 "\n",1773 __func__, (u64)sym.st_value, (u64)phdr.p_vaddr,1774 (u64)phdr.p_offset);1775 sym.st_value -= phdr.p_vaddr - phdr.p_offset;1776 }1777 }1778 1779 demangled = demangle_sym(dso, kmodule, elf_name);1780 if (demangled != NULL)1781 elf_name = demangled;1782 1783 f = symbol__new(sym.st_value, sym.st_size,1784 GELF_ST_BIND(sym.st_info),1785 GELF_ST_TYPE(sym.st_info), elf_name);1786 free(demangled);1787 if (!f)1788 goto out_elf_end;1789 1790 arch__sym_update(f, &sym);1791 1792 __symbols__insert(dso__symbols(curr_dso), f, dso__kernel(dso));1793 nr++;1794 }1795 dso__put(curr_dso);1796 1797 /*1798 * For misannotated, zeroed, ASM function sizes.1799 */1800 if (nr > 0) {1801 symbols__fixup_end(dso__symbols(dso), false);1802 symbols__fixup_duplicate(dso__symbols(dso));1803 if (kmap) {1804 /*1805 * We need to fixup this here too because we create new1806 * maps here, for things like vsyscall sections.1807 */1808 maps__fixup_end(kmaps);1809 }1810 }1811 return nr;1812out_elf_end:1813 dso__put(curr_dso);1814 return -1;1815}1816 1817int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,1818 struct symsrc *runtime_ss, int kmodule)1819{1820 int nr = 0;1821 int err = -1;1822 1823 dso__set_symtab_type(dso, syms_ss->type);1824 dso__set_is_64_bit(dso, syms_ss->is_64_bit);1825 dso__set_rel(dso, syms_ss->ehdr.e_type == ET_REL);1826 1827 /*1828 * Modules may already have symbols from kallsyms, but those symbols1829 * have the wrong values for the dso maps, so remove them.1830 */1831 if (kmodule && syms_ss->symtab)1832 symbols__delete(dso__symbols(dso));1833 1834 if (!syms_ss->symtab) {1835 /*1836 * If the vmlinux is stripped, fail so we will fall back1837 * to using kallsyms. The vmlinux runtime symbols aren't1838 * of much use.1839 */1840 if (dso__kernel(dso))1841 return err;1842 } else {1843 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,1844 kmodule, 0);1845 if (err < 0)1846 return err;1847 nr = err;1848 }1849 1850 if (syms_ss->dynsym) {1851 err = dso__load_sym_internal(dso, map, syms_ss, runtime_ss,1852 kmodule, 1);1853 if (err < 0)1854 return err;1855 err += nr;1856 }1857 1858 return err;1859}1860 1861static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)1862{1863 GElf_Phdr phdr;1864 size_t i, phdrnum;1865 int err;1866 u64 sz;1867 1868 if (elf_getphdrnum(elf, &phdrnum))1869 return -1;1870 1871 for (i = 0; i < phdrnum; i++) {1872 if (gelf_getphdr(elf, i, &phdr) == NULL)1873 return -1;1874 if (phdr.p_type != PT_LOAD)1875 continue;1876 if (exe) {1877 if (!(phdr.p_flags & PF_X))1878 continue;1879 } else {1880 if (!(phdr.p_flags & PF_R))1881 continue;1882 }1883 sz = min(phdr.p_memsz, phdr.p_filesz);1884 if (!sz)1885 continue;1886 err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);1887 if (err)1888 return err;1889 }1890 return 0;1891}1892 1893int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,1894 bool *is_64_bit)1895{1896 int err;1897 Elf *elf;1898 1899 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);1900 if (elf == NULL)1901 return -1;1902 1903 if (is_64_bit)1904 *is_64_bit = (gelf_getclass(elf) == ELFCLASS64);1905 1906 err = elf_read_maps(elf, exe, mapfn, data);1907 1908 elf_end(elf);1909 return err;1910}1911 1912enum dso_type dso__type_fd(int fd)1913{1914 enum dso_type dso_type = DSO__TYPE_UNKNOWN;1915 GElf_Ehdr ehdr;1916 Elf_Kind ek;1917 Elf *elf;1918 1919 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);1920 if (elf == NULL)1921 goto out;1922 1923 ek = elf_kind(elf);1924 if (ek != ELF_K_ELF)1925 goto out_end;1926 1927 if (gelf_getclass(elf) == ELFCLASS64) {1928 dso_type = DSO__TYPE_64BIT;1929 goto out_end;1930 }1931 1932 if (gelf_getehdr(elf, &ehdr) == NULL)1933 goto out_end;1934 1935 if (ehdr.e_machine == EM_X86_64)1936 dso_type = DSO__TYPE_X32BIT;1937 else1938 dso_type = DSO__TYPE_32BIT;1939out_end:1940 elf_end(elf);1941out:1942 return dso_type;1943}1944 1945static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)1946{1947 ssize_t r;1948 size_t n;1949 int err = -1;1950 char *buf = malloc(page_size);1951 1952 if (buf == NULL)1953 return -1;1954 1955 if (lseek(to, to_offs, SEEK_SET) != to_offs)1956 goto out;1957 1958 if (lseek(from, from_offs, SEEK_SET) != from_offs)1959 goto out;1960 1961 while (len) {1962 n = page_size;1963 if (len < n)1964 n = len;1965 /* Use read because mmap won't work on proc files */1966 r = read(from, buf, n);1967 if (r < 0)1968 goto out;1969 if (!r)1970 break;1971 n = r;1972 r = write(to, buf, n);1973 if (r < 0)1974 goto out;1975 if ((size_t)r != n)1976 goto out;1977 len -= n;1978 }1979 1980 err = 0;1981out:1982 free(buf);1983 return err;1984}1985 1986struct kcore {1987 int fd;1988 int elfclass;1989 Elf *elf;1990 GElf_Ehdr ehdr;1991};1992 1993static int kcore__open(struct kcore *kcore, const char *filename)1994{1995 GElf_Ehdr *ehdr;1996 1997 kcore->fd = open(filename, O_RDONLY);1998 if (kcore->fd == -1)1999 return -1;2000 2001 kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);2002 if (!kcore->elf)2003 goto out_close;2004 2005 kcore->elfclass = gelf_getclass(kcore->elf);2006 if (kcore->elfclass == ELFCLASSNONE)2007 goto out_end;2008 2009 ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);2010 if (!ehdr)2011 goto out_end;2012 2013 return 0;2014 2015out_end:2016 elf_end(kcore->elf);2017out_close:2018 close(kcore->fd);2019 return -1;2020}2021 2022static int kcore__init(struct kcore *kcore, char *filename, int elfclass,2023 bool temp)2024{2025 kcore->elfclass = elfclass;2026 2027 if (temp)2028 kcore->fd = mkstemp(filename);2029 else2030 kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);2031 if (kcore->fd == -1)2032 return -1;2033 2034 kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);2035 if (!kcore->elf)2036 goto out_close;2037 2038 if (!gelf_newehdr(kcore->elf, elfclass))2039 goto out_end;2040 2041 memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));2042 2043 return 0;2044 2045out_end:2046 elf_end(kcore->elf);2047out_close:2048 close(kcore->fd);2049 unlink(filename);2050 return -1;2051}2052 2053static void kcore__close(struct kcore *kcore)2054{2055 elf_end(kcore->elf);2056 close(kcore->fd);2057}2058 2059static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)2060{2061 GElf_Ehdr *ehdr = &to->ehdr;2062 GElf_Ehdr *kehdr = &from->ehdr;2063 2064 memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);2065 ehdr->e_type = kehdr->e_type;2066 ehdr->e_machine = kehdr->e_machine;2067 ehdr->e_version = kehdr->e_version;2068 ehdr->e_entry = 0;2069 ehdr->e_shoff = 0;2070 ehdr->e_flags = kehdr->e_flags;2071 ehdr->e_phnum = count;2072 ehdr->e_shentsize = 0;2073 ehdr->e_shnum = 0;2074 ehdr->e_shstrndx = 0;2075 2076 if (from->elfclass == ELFCLASS32) {2077 ehdr->e_phoff = sizeof(Elf32_Ehdr);2078 ehdr->e_ehsize = sizeof(Elf32_Ehdr);2079 ehdr->e_phentsize = sizeof(Elf32_Phdr);2080 } else {2081 ehdr->e_phoff = sizeof(Elf64_Ehdr);2082 ehdr->e_ehsize = sizeof(Elf64_Ehdr);2083 ehdr->e_phentsize = sizeof(Elf64_Phdr);2084 }2085 2086 if (!gelf_update_ehdr(to->elf, ehdr))2087 return -1;2088 2089 if (!gelf_newphdr(to->elf, count))2090 return -1;2091 2092 return 0;2093}2094 2095static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,2096 u64 addr, u64 len)2097{2098 GElf_Phdr phdr = {2099 .p_type = PT_LOAD,2100 .p_flags = PF_R | PF_W | PF_X,2101 .p_offset = offset,2102 .p_vaddr = addr,2103 .p_paddr = 0,2104 .p_filesz = len,2105 .p_memsz = len,2106 .p_align = page_size,2107 };2108 2109 if (!gelf_update_phdr(kcore->elf, idx, &phdr))2110 return -1;2111 2112 return 0;2113}2114 2115static off_t kcore__write(struct kcore *kcore)2116{2117 return elf_update(kcore->elf, ELF_C_WRITE);2118}2119 2120struct phdr_data {2121 off_t offset;2122 off_t rel;2123 u64 addr;2124 u64 len;2125 struct list_head node;2126 struct phdr_data *remaps;2127};2128 2129struct sym_data {2130 u64 addr;2131 struct list_head node;2132};2133 2134struct kcore_copy_info {2135 u64 stext;2136 u64 etext;2137 u64 first_symbol;2138 u64 last_symbol;2139 u64 first_module;2140 u64 first_module_symbol;2141 u64 last_module_symbol;2142 size_t phnum;2143 struct list_head phdrs;2144 struct list_head syms;2145};2146 2147#define kcore_copy__for_each_phdr(k, p) \2148 list_for_each_entry((p), &(k)->phdrs, node)2149 2150static struct phdr_data *phdr_data__new(u64 addr, u64 len, off_t offset)2151{2152 struct phdr_data *p = zalloc(sizeof(*p));2153 2154 if (p) {2155 p->addr = addr;2156 p->len = len;2157 p->offset = offset;2158 }2159 2160 return p;2161}2162 2163static struct phdr_data *kcore_copy_info__addnew(struct kcore_copy_info *kci,2164 u64 addr, u64 len,2165 off_t offset)2166{2167 struct phdr_data *p = phdr_data__new(addr, len, offset);2168 2169 if (p)2170 list_add_tail(&p->node, &kci->phdrs);2171 2172 return p;2173}2174 2175static void kcore_copy__free_phdrs(struct kcore_copy_info *kci)2176{2177 struct phdr_data *p, *tmp;2178 2179 list_for_each_entry_safe(p, tmp, &kci->phdrs, node) {2180 list_del_init(&p->node);2181 free(p);2182 }2183}2184 2185static struct sym_data *kcore_copy__new_sym(struct kcore_copy_info *kci,2186 u64 addr)2187{2188 struct sym_data *s = zalloc(sizeof(*s));2189 2190 if (s) {2191 s->addr = addr;2192 list_add_tail(&s->node, &kci->syms);2193 }2194 2195 return s;2196}2197 2198static void kcore_copy__free_syms(struct kcore_copy_info *kci)2199{2200 struct sym_data *s, *tmp;2201 2202 list_for_each_entry_safe(s, tmp, &kci->syms, node) {2203 list_del_init(&s->node);2204 free(s);2205 }2206}2207 2208static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,2209 u64 start)2210{2211 struct kcore_copy_info *kci = arg;2212 2213 if (!kallsyms__is_function(type))2214 return 0;2215 2216 if (strchr(name, '[')) {2217 if (!kci->first_module_symbol || start < kci->first_module_symbol)2218 kci->first_module_symbol = start;2219 if (start > kci->last_module_symbol)2220 kci->last_module_symbol = start;2221 return 0;2222 }2223 2224 if (!kci->first_symbol || start < kci->first_symbol)2225 kci->first_symbol = start;2226 2227 if (!kci->last_symbol || start > kci->last_symbol)2228 kci->last_symbol = start;2229 2230 if (!strcmp(name, "_stext")) {2231 kci->stext = start;2232 return 0;2233 }2234 2235 if (!strcmp(name, "_etext")) {2236 kci->etext = start;2237 return 0;2238 }2239 2240 if (is_entry_trampoline(name) && !kcore_copy__new_sym(kci, start))2241 return -1;2242 2243 return 0;2244}2245 2246static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,2247 const char *dir)2248{2249 char kallsyms_filename[PATH_MAX];2250 2251 scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);2252 2253 if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))2254 return -1;2255 2256 if (kallsyms__parse(kallsyms_filename, kci,2257 kcore_copy__process_kallsyms) < 0)2258 return -1;2259 2260 return 0;2261}2262 2263static int kcore_copy__process_modules(void *arg,2264 const char *name __maybe_unused,2265 u64 start, u64 size __maybe_unused)2266{2267 struct kcore_copy_info *kci = arg;2268 2269 if (!kci->first_module || start < kci->first_module)2270 kci->first_module = start;2271 2272 return 0;2273}2274 2275static int kcore_copy__parse_modules(struct kcore_copy_info *kci,2276 const char *dir)2277{2278 char modules_filename[PATH_MAX];2279 2280 scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);2281 2282 if (symbol__restricted_filename(modules_filename, "/proc/modules"))2283 return -1;2284 2285 if (modules__parse(modules_filename, kci,2286 kcore_copy__process_modules) < 0)2287 return -1;2288 2289 return 0;2290}2291 2292static int kcore_copy__map(struct kcore_copy_info *kci, u64 start, u64 end,2293 u64 pgoff, u64 s, u64 e)2294{2295 u64 len, offset;2296 2297 if (s < start || s >= end)2298 return 0;2299 2300 offset = (s - start) + pgoff;2301 len = e < end ? e - s : end - s;2302 2303 return kcore_copy_info__addnew(kci, s, len, offset) ? 0 : -1;2304}2305 2306static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)2307{2308 struct kcore_copy_info *kci = data;2309 u64 end = start + len;2310 struct sym_data *sdat;2311 2312 if (kcore_copy__map(kci, start, end, pgoff, kci->stext, kci->etext))2313 return -1;2314 2315 if (kcore_copy__map(kci, start, end, pgoff, kci->first_module,2316 kci->last_module_symbol))2317 return -1;2318 2319 list_for_each_entry(sdat, &kci->syms, node) {2320 u64 s = round_down(sdat->addr, page_size);2321 2322 if (kcore_copy__map(kci, start, end, pgoff, s, s + len))2323 return -1;2324 }2325 2326 return 0;2327}2328 2329static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)2330{2331 if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)2332 return -1;2333 2334 return 0;2335}2336 2337static void kcore_copy__find_remaps(struct kcore_copy_info *kci)2338{2339 struct phdr_data *p, *k = NULL;2340 u64 kend;2341 2342 if (!kci->stext)2343 return;2344 2345 /* Find phdr that corresponds to the kernel map (contains stext) */2346 kcore_copy__for_each_phdr(kci, p) {2347 u64 pend = p->addr + p->len - 1;2348 2349 if (p->addr <= kci->stext && pend >= kci->stext) {2350 k = p;2351 break;2352 }2353 }2354 2355 if (!k)2356 return;2357 2358 kend = k->offset + k->len;2359 2360 /* Find phdrs that remap the kernel */2361 kcore_copy__for_each_phdr(kci, p) {2362 u64 pend = p->offset + p->len;2363 2364 if (p == k)2365 continue;2366 2367 if (p->offset >= k->offset && pend <= kend)2368 p->remaps = k;2369 }2370}2371 2372static void kcore_copy__layout(struct kcore_copy_info *kci)2373{2374 struct phdr_data *p;2375 off_t rel = 0;2376 2377 kcore_copy__find_remaps(kci);2378 2379 kcore_copy__for_each_phdr(kci, p) {2380 if (!p->remaps) {2381 p->rel = rel;2382 rel += p->len;2383 }2384 kci->phnum += 1;2385 }2386 2387 kcore_copy__for_each_phdr(kci, p) {2388 struct phdr_data *k = p->remaps;2389 2390 if (k)2391 p->rel = p->offset - k->offset + k->rel;2392 }2393}2394 2395static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,2396 Elf *elf)2397{2398 if (kcore_copy__parse_kallsyms(kci, dir))2399 return -1;2400 2401 if (kcore_copy__parse_modules(kci, dir))2402 return -1;2403 2404 if (kci->stext)2405 kci->stext = round_down(kci->stext, page_size);2406 else2407 kci->stext = round_down(kci->first_symbol, page_size);2408 2409 if (kci->etext) {2410 kci->etext = round_up(kci->etext, page_size);2411 } else if (kci->last_symbol) {2412 kci->etext = round_up(kci->last_symbol, page_size);2413 kci->etext += page_size;2414 }2415 2416 if (kci->first_module_symbol &&2417 (!kci->first_module || kci->first_module_symbol < kci->first_module))2418 kci->first_module = kci->first_module_symbol;2419 2420 kci->first_module = round_down(kci->first_module, page_size);2421 2422 if (kci->last_module_symbol) {2423 kci->last_module_symbol = round_up(kci->last_module_symbol,2424 page_size);2425 kci->last_module_symbol += page_size;2426 }2427 2428 if (!kci->stext || !kci->etext)2429 return -1;2430 2431 if (kci->first_module && !kci->last_module_symbol)2432 return -1;2433 2434 if (kcore_copy__read_maps(kci, elf))2435 return -1;2436 2437 kcore_copy__layout(kci);2438 2439 return 0;2440}2441 2442static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,2443 const char *name)2444{2445 char from_filename[PATH_MAX];2446 char to_filename[PATH_MAX];2447 2448 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);2449 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);2450 2451 return copyfile_mode(from_filename, to_filename, 0400);2452}2453 2454static int kcore_copy__unlink(const char *dir, const char *name)2455{2456 char filename[PATH_MAX];2457 2458 scnprintf(filename, PATH_MAX, "%s/%s", dir, name);2459 2460 return unlink(filename);2461}2462 2463static int kcore_copy__compare_fds(int from, int to)2464{2465 char *buf_from;2466 char *buf_to;2467 ssize_t ret;2468 size_t len;2469 int err = -1;2470 2471 buf_from = malloc(page_size);2472 buf_to = malloc(page_size);2473 if (!buf_from || !buf_to)2474 goto out;2475 2476 while (1) {2477 /* Use read because mmap won't work on proc files */2478 ret = read(from, buf_from, page_size);2479 if (ret < 0)2480 goto out;2481 2482 if (!ret)2483 break;2484 2485 len = ret;2486 2487 if (readn(to, buf_to, len) != (int)len)2488 goto out;2489 2490 if (memcmp(buf_from, buf_to, len))2491 goto out;2492 }2493 2494 err = 0;2495out:2496 free(buf_to);2497 free(buf_from);2498 return err;2499}2500 2501static int kcore_copy__compare_files(const char *from_filename,2502 const char *to_filename)2503{2504 int from, to, err = -1;2505 2506 from = open(from_filename, O_RDONLY);2507 if (from < 0)2508 return -1;2509 2510 to = open(to_filename, O_RDONLY);2511 if (to < 0)2512 goto out_close_from;2513 2514 err = kcore_copy__compare_fds(from, to);2515 2516 close(to);2517out_close_from:2518 close(from);2519 return err;2520}2521 2522static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,2523 const char *name)2524{2525 char from_filename[PATH_MAX];2526 char to_filename[PATH_MAX];2527 2528 scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);2529 scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);2530 2531 return kcore_copy__compare_files(from_filename, to_filename);2532}2533 2534/**2535 * kcore_copy - copy kallsyms, modules and kcore from one directory to another.2536 * @from_dir: from directory2537 * @to_dir: to directory2538 *2539 * This function copies kallsyms, modules and kcore files from one directory to2540 * another. kallsyms and modules are copied entirely. Only code segments are2541 * copied from kcore. It is assumed that two segments suffice: one for the2542 * kernel proper and one for all the modules. The code segments are determined2543 * from kallsyms and modules files. The kernel map starts at _stext or the2544 * lowest function symbol, and ends at _etext or the highest function symbol.2545 * The module map starts at the lowest module address and ends at the highest2546 * module symbol. Start addresses are rounded down to the nearest page. End2547 * addresses are rounded up to the nearest page. An extra page is added to the2548 * highest kernel symbol and highest module symbol to, hopefully, encompass that2549 * symbol too. Because it contains only code sections, the resulting kcore is2550 * unusual. One significant peculiarity is that the mapping (start -> pgoff)2551 * is not the same for the kernel map and the modules map. That happens because2552 * the data is copied adjacently whereas the original kcore has gaps. Finally,2553 * kallsyms file is compared with its copy to check that modules have not been2554 * loaded or unloaded while the copies were taking place.2555 *2556 * Return: %0 on success, %-1 on failure.2557 */2558int kcore_copy(const char *from_dir, const char *to_dir)2559{2560 struct kcore kcore;2561 struct kcore extract;2562 int idx = 0, err = -1;2563 off_t offset, sz;2564 struct kcore_copy_info kci = { .stext = 0, };2565 char kcore_filename[PATH_MAX];2566 char extract_filename[PATH_MAX];2567 struct phdr_data *p;2568 2569 INIT_LIST_HEAD(&kci.phdrs);2570 INIT_LIST_HEAD(&kci.syms);2571 2572 if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))2573 return -1;2574 2575 if (kcore_copy__copy_file(from_dir, to_dir, "modules"))2576 goto out_unlink_kallsyms;2577 2578 scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);2579 scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);2580 2581 if (kcore__open(&kcore, kcore_filename))2582 goto out_unlink_modules;2583 2584 if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))2585 goto out_kcore_close;2586 2587 if (kcore__init(&extract, extract_filename, kcore.elfclass, false))2588 goto out_kcore_close;2589 2590 if (kcore__copy_hdr(&kcore, &extract, kci.phnum))2591 goto out_extract_close;2592 2593 offset = gelf_fsize(extract.elf, ELF_T_EHDR, 1, EV_CURRENT) +2594 gelf_fsize(extract.elf, ELF_T_PHDR, kci.phnum, EV_CURRENT);2595 offset = round_up(offset, page_size);2596 2597 kcore_copy__for_each_phdr(&kci, p) {2598 off_t offs = p->rel + offset;2599 2600 if (kcore__add_phdr(&extract, idx++, offs, p->addr, p->len))2601 goto out_extract_close;2602 }2603 2604 sz = kcore__write(&extract);2605 if (sz < 0 || sz > offset)2606 goto out_extract_close;2607 2608 kcore_copy__for_each_phdr(&kci, p) {2609 off_t offs = p->rel + offset;2610 2611 if (p->remaps)2612 continue;2613 if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))2614 goto out_extract_close;2615 }2616 2617 if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))2618 goto out_extract_close;2619 2620 err = 0;2621 2622out_extract_close:2623 kcore__close(&extract);2624 if (err)2625 unlink(extract_filename);2626out_kcore_close:2627 kcore__close(&kcore);2628out_unlink_modules:2629 if (err)2630 kcore_copy__unlink(to_dir, "modules");2631out_unlink_kallsyms:2632 if (err)2633 kcore_copy__unlink(to_dir, "kallsyms");2634 2635 kcore_copy__free_phdrs(&kci);2636 kcore_copy__free_syms(&kci);2637 2638 return err;2639}2640 2641int kcore_extract__create(struct kcore_extract *kce)2642{2643 struct kcore kcore;2644 struct kcore extract;2645 size_t count = 1;2646 int idx = 0, err = -1;2647 off_t offset = page_size, sz;2648 2649 if (kcore__open(&kcore, kce->kcore_filename))2650 return -1;2651 2652 strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);2653 if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))2654 goto out_kcore_close;2655 2656 if (kcore__copy_hdr(&kcore, &extract, count))2657 goto out_extract_close;2658 2659 if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))2660 goto out_extract_close;2661 2662 sz = kcore__write(&extract);2663 if (sz < 0 || sz > offset)2664 goto out_extract_close;2665 2666 if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))2667 goto out_extract_close;2668 2669 err = 0;2670 2671out_extract_close:2672 kcore__close(&extract);2673 if (err)2674 unlink(kce->extract_filename);2675out_kcore_close:2676 kcore__close(&kcore);2677 2678 return err;2679}2680 2681void kcore_extract__delete(struct kcore_extract *kce)2682{2683 unlink(kce->extract_filename);2684}2685 2686#ifdef HAVE_GELF_GETNOTE_SUPPORT2687 2688static void sdt_adjust_loc(struct sdt_note *tmp, GElf_Addr base_off)2689{2690 if (!base_off)2691 return;2692 2693 if (tmp->bit32)2694 tmp->addr.a32[SDT_NOTE_IDX_LOC] =2695 tmp->addr.a32[SDT_NOTE_IDX_LOC] + base_off -2696 tmp->addr.a32[SDT_NOTE_IDX_BASE];2697 else2698 tmp->addr.a64[SDT_NOTE_IDX_LOC] =2699 tmp->addr.a64[SDT_NOTE_IDX_LOC] + base_off -2700 tmp->addr.a64[SDT_NOTE_IDX_BASE];2701}2702 2703static void sdt_adjust_refctr(struct sdt_note *tmp, GElf_Addr base_addr,2704 GElf_Addr base_off)2705{2706 if (!base_off)2707 return;2708 2709 if (tmp->bit32 && tmp->addr.a32[SDT_NOTE_IDX_REFCTR])2710 tmp->addr.a32[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);2711 else if (tmp->addr.a64[SDT_NOTE_IDX_REFCTR])2712 tmp->addr.a64[SDT_NOTE_IDX_REFCTR] -= (base_addr - base_off);2713}2714 2715/**2716 * populate_sdt_note : Parse raw data and identify SDT note2717 * @elf: elf of the opened file2718 * @data: raw data of a section with description offset applied2719 * @len: note description size2720 * @type: type of the note2721 * @sdt_notes: List to add the SDT note2722 *2723 * Responsible for parsing the @data in section .note.stapsdt in @elf and2724 * if its an SDT note, it appends to @sdt_notes list.2725 */2726static int populate_sdt_note(Elf **elf, const char *data, size_t len,2727 struct list_head *sdt_notes)2728{2729 const char *provider, *name, *args;2730 struct sdt_note *tmp = NULL;2731 GElf_Ehdr ehdr;2732 GElf_Shdr shdr;2733 int ret = -EINVAL;2734 2735 union {2736 Elf64_Addr a64[NR_ADDR];2737 Elf32_Addr a32[NR_ADDR];2738 } buf;2739 2740 Elf_Data dst = {2741 .d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,2742 .d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),2743 .d_off = 0, .d_align = 02744 };2745 Elf_Data src = {2746 .d_buf = (void *) data, .d_type = ELF_T_ADDR,2747 .d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,2748 .d_align = 02749 };2750 2751 tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));2752 if (!tmp) {2753 ret = -ENOMEM;2754 goto out_err;2755 }2756 2757 INIT_LIST_HEAD(&tmp->note_list);2758 2759 if (len < dst.d_size + 3)2760 goto out_free_note;2761 2762 /* Translation from file representation to memory representation */2763 if (gelf_xlatetom(*elf, &dst, &src,2764 elf_getident(*elf, NULL)[EI_DATA]) == NULL) {2765 pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));2766 goto out_free_note;2767 }2768 2769 /* Populate the fields of sdt_note */2770 provider = data + dst.d_size;2771 2772 name = (const char *)memchr(provider, '\0', data + len - provider);2773 if (name++ == NULL)2774 goto out_free_note;2775 2776 tmp->provider = strdup(provider);2777 if (!tmp->provider) {2778 ret = -ENOMEM;2779 goto out_free_note;2780 }2781 tmp->name = strdup(name);2782 if (!tmp->name) {2783 ret = -ENOMEM;2784 goto out_free_prov;2785 }2786 2787 args = memchr(name, '\0', data + len - name);2788 2789 /*2790 * There is no argument if:2791 * - We reached the end of the note;2792 * - There is not enough room to hold a potential string;2793 * - The argument string is empty or just contains ':'.2794 */2795 if (args == NULL || data + len - args < 2 ||2796 args[1] == ':' || args[1] == '\0')2797 tmp->args = NULL;2798 else {2799 tmp->args = strdup(++args);2800 if (!tmp->args) {2801 ret = -ENOMEM;2802 goto out_free_name;2803 }2804 }2805 2806 if (gelf_getclass(*elf) == ELFCLASS32) {2807 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));2808 tmp->bit32 = true;2809 } else {2810 memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));2811 tmp->bit32 = false;2812 }2813 2814 if (!gelf_getehdr(*elf, &ehdr)) {2815 pr_debug("%s : cannot get elf header.\n", __func__);2816 ret = -EBADF;2817 goto out_free_args;2818 }2819 2820 /* Adjust the prelink effect :2821 * Find out the .stapsdt.base section.2822 * This scn will help us to handle prelinking (if present).2823 * Compare the retrieved file offset of the base section with the2824 * base address in the description of the SDT note. If its different,2825 * then accordingly, adjust the note location.2826 */2827 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))2828 sdt_adjust_loc(tmp, shdr.sh_offset);2829 2830 /* Adjust reference counter offset */2831 if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL))2832 sdt_adjust_refctr(tmp, shdr.sh_addr, shdr.sh_offset);2833 2834 list_add_tail(&tmp->note_list, sdt_notes);2835 return 0;2836 2837out_free_args:2838 zfree(&tmp->args);2839out_free_name:2840 zfree(&tmp->name);2841out_free_prov:2842 zfree(&tmp->provider);2843out_free_note:2844 free(tmp);2845out_err:2846 return ret;2847}2848 2849/**2850 * construct_sdt_notes_list : constructs a list of SDT notes2851 * @elf : elf to look into2852 * @sdt_notes : empty list_head2853 *2854 * Scans the sections in 'elf' for the section2855 * .note.stapsdt. It, then calls populate_sdt_note to find2856 * out the SDT events and populates the 'sdt_notes'.2857 */2858static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)2859{2860 GElf_Ehdr ehdr;2861 Elf_Scn *scn = NULL;2862 Elf_Data *data;2863 GElf_Shdr shdr;2864 size_t shstrndx, next;2865 GElf_Nhdr nhdr;2866 size_t name_off, desc_off, offset;2867 int ret = 0;2868 2869 if (gelf_getehdr(elf, &ehdr) == NULL) {2870 ret = -EBADF;2871 goto out_ret;2872 }2873 if (elf_getshdrstrndx(elf, &shstrndx) != 0) {2874 ret = -EBADF;2875 goto out_ret;2876 }2877 2878 /* Look for the required section */2879 scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);2880 if (!scn) {2881 ret = -ENOENT;2882 goto out_ret;2883 }2884 2885 if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {2886 ret = -ENOENT;2887 goto out_ret;2888 }2889 2890 data = elf_getdata(scn, NULL);2891 2892 /* Get the SDT notes */2893 for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,2894 &desc_off)) > 0; offset = next) {2895 if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&2896 !memcmp(data->d_buf + name_off, SDT_NOTE_NAME,2897 sizeof(SDT_NOTE_NAME))) {2898 /* Check the type of the note */2899 if (nhdr.n_type != SDT_NOTE_TYPE)2900 goto out_ret;2901 2902 ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),2903 nhdr.n_descsz, sdt_notes);2904 if (ret < 0)2905 goto out_ret;2906 }2907 }2908 if (list_empty(sdt_notes))2909 ret = -ENOENT;2910 2911out_ret:2912 return ret;2913}2914 2915/**2916 * get_sdt_note_list : Wrapper to construct a list of sdt notes2917 * @head : empty list_head2918 * @target : file to find SDT notes from2919 *2920 * This opens the file, initializes2921 * the ELF and then calls construct_sdt_notes_list.2922 */2923int get_sdt_note_list(struct list_head *head, const char *target)2924{2925 Elf *elf;2926 int fd, ret;2927 2928 fd = open(target, O_RDONLY);2929 if (fd < 0)2930 return -EBADF;2931 2932 elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);2933 if (!elf) {2934 ret = -EBADF;2935 goto out_close;2936 }2937 ret = construct_sdt_notes_list(elf, head);2938 elf_end(elf);2939out_close:2940 close(fd);2941 return ret;2942}2943 2944/**2945 * cleanup_sdt_note_list : free the sdt notes' list2946 * @sdt_notes: sdt notes' list2947 *2948 * Free up the SDT notes in @sdt_notes.2949 * Returns the number of SDT notes free'd.2950 */2951int cleanup_sdt_note_list(struct list_head *sdt_notes)2952{2953 struct sdt_note *tmp, *pos;2954 int nr_free = 0;2955 2956 list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {2957 list_del_init(&pos->note_list);2958 zfree(&pos->args);2959 zfree(&pos->name);2960 zfree(&pos->provider);2961 free(pos);2962 nr_free++;2963 }2964 return nr_free;2965}2966 2967/**2968 * sdt_notes__get_count: Counts the number of sdt events2969 * @start: list_head to sdt_notes list2970 *2971 * Returns the number of SDT notes in a list2972 */2973int sdt_notes__get_count(struct list_head *start)2974{2975 struct sdt_note *sdt_ptr;2976 int count = 0;2977 2978 list_for_each_entry(sdt_ptr, start, note_list)2979 count++;2980 return count;2981}2982#endif2983 2984void symbol__elf_init(void)2985{2986 elf_version(EV_CURRENT);2987}2988