tools/objtool/orc_dump.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
   4  */
   5
   6 #include <unistd.h>
   7 #include <asm/orc_types.h>
   8 #include <objtool/objtool.h>
   9 #include <objtool/orc.h>
  10 #include <objtool/warn.h>
  11 #include <objtool/endianness.h>
  12
  13 int orc_dump(const char *_objname)
  14 {
  15         int fd, nr_entries, i, *orc_ip = NULL, orc_size = 0;
  16         struct orc_entry *orc = NULL;
  17         char *name;
  18         size_t nr_sections;
  19         Elf64_Addr orc_ip_addr = 0;
  20         size_t shstrtab_idx, strtab_idx = 0;
  21         Elf *elf;
  22         Elf_Scn *scn;
  23         GElf_Shdr sh;
  24         GElf_Rela rela;
  25         GElf_Sym sym;
  26         Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
  27         struct elf dummy_elf = {};
  28
  29
  30         objname = _objname;
  31
  32         elf_version(EV_CURRENT);
  33
  34         fd = open(objname, O_RDONLY);
  35         if (fd == -1) {
  36                 perror("open");
  37                 return -1;
  38         }
  39
  40         elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
  41         if (!elf) {
  42                 WARN_ELF("elf_begin");
  43                 return -1;
  44         }
  45
  46         if (!elf64_getehdr(elf)) {
  47                 WARN_ELF("elf64_getehdr");
  48                 return -1;
  49         }
  50         memcpy(&dummy_elf.ehdr, elf64_getehdr(elf), sizeof(dummy_elf.ehdr));
  51
  52         if (elf_getshdrnum(elf, &nr_sections)) {
  53                 WARN_ELF("elf_getshdrnum");
  54                 return -1;
  55         }
  56
  57         if (elf_getshdrstrndx(elf, &shstrtab_idx)) {
  58                 WARN_ELF("elf_getshdrstrndx");
  59                 return -1;
  60         }
  61
  62         for (i = 0; i < nr_sections; i++) {
  63                 scn = elf_getscn(elf, i);
  64                 if (!scn) {
  65                         WARN_ELF("elf_getscn");
  66                         return -1;
  67                 }
  68
  69                 if (!gelf_getshdr(scn, &sh)) {
  70                         WARN_ELF("gelf_getshdr");
  71                         return -1;
  72                 }
  73
  74                 name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
  75                 if (!name) {
  76                         WARN_ELF("elf_strptr");
  77                         return -1;
  78                 }
  79
  80                 data = elf_getdata(scn, NULL);
  81                 if (!data) {
  82                         WARN_ELF("elf_getdata");
  83                         return -1;
  84                 }
  85
  86                 if (!strcmp(name, ".symtab")) {
  87                         symtab = data;
  88                 } else if (!strcmp(name, ".strtab")) {
  89                         strtab_idx = i;
  90                 } else if (!strcmp(name, ".orc_unwind")) {
  91                         orc = data->d_buf;
  92                         orc_size = sh.sh_size;
  93                 } else if (!strcmp(name, ".orc_unwind_ip")) {
  94                         orc_ip = data->d_buf;
  95                         orc_ip_addr = sh.sh_addr;
  96                 } else if (!strcmp(name, ".rela.orc_unwind_ip")) {
  97                         rela_orc_ip = data;
  98                 }
  99         }
 100
 101         if (!symtab || !strtab_idx || !orc || !orc_ip)
 102                 return 0;
 103
 104         if (orc_size % sizeof(*orc) != 0) {
 105                 WARN("bad .orc_unwind section size");
 106                 return -1;
 107         }
 108
 109         nr_entries = orc_size / sizeof(*orc);
 110         for (i = 0; i < nr_entries; i++) {
 111                 if (rela_orc_ip) {
 112                         if (!gelf_getrela(rela_orc_ip, i, &rela)) {
 113                                 WARN_ELF("gelf_getrela");
 114                                 return -1;
 115                         }
 116
 117                         if (!gelf_getsym(symtab, GELF_R_SYM(rela.r_info), &sym)) {
 118                                 WARN_ELF("gelf_getsym");
 119                                 return -1;
 120                         }
 121
 122                         if (GELF_ST_TYPE(sym.st_info) == STT_SECTION) {
 123                                 scn = elf_getscn(elf, sym.st_shndx);
 124                                 if (!scn) {
 125                                         WARN_ELF("elf_getscn");
 126                                         return -1;
 127                                 }
 128
 129                                 if (!gelf_getshdr(scn, &sh)) {
 130                                         WARN_ELF("gelf_getshdr");
 131                                         return -1;
 132                                 }
 133
 134                                 name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
 135                                 if (!name) {
 136                                         WARN_ELF("elf_strptr");
 137                                         return -1;
 138                                 }
 139                         } else {
 140                                 name = elf_strptr(elf, strtab_idx, sym.st_name);
 141                                 if (!name) {
 142                                         WARN_ELF("elf_strptr");
 143                                         return -1;
 144                                 }
 145                         }
 146
 147                         printf("%s+%llx:", name, (unsigned long long)rela.r_addend);
 148
 149                 } else {
 150                         printf("%llx:", (unsigned long long)(orc_ip_addr + (i * sizeof(int)) + orc_ip[i]));
 151                 }
 152
 153                 orc_print_dump(&dummy_elf, orc, i);
 154         }
 155
 156         elf_end(elf);
 157         close(fd);
 158
 159         return 0;
 160 }