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/warn.h>
  10 #include <objtool/endianness.h>
  11
  12 static const char *reg_name(unsigned int reg)
  13 {
  14         switch (reg) {
  15         case ORC_REG_PREV_SP:
  16                 return "prevsp";
  17         case ORC_REG_DX:
  18                 return "dx";
  19         case ORC_REG_DI:
  20                 return "di";
  21         case ORC_REG_BP:
  22                 return "bp";
  23         case ORC_REG_SP:
  24                 return "sp";
  25         case ORC_REG_R10:
  26                 return "r10";
  27         case ORC_REG_R13:
  28                 return "r13";
  29         case ORC_REG_BP_INDIRECT:
  30                 return "bp(ind)";
  31         case ORC_REG_SP_INDIRECT:
  32                 return "sp(ind)";
  33         default:
  34                 return "?";
  35         }
  36 }
  37
  38 static const char *orc_type_name(unsigned int type)
  39 {
  40         switch (type) {
  41         case ORC_TYPE_UNDEFINED:
  42                 return "(und)";
  43         case ORC_TYPE_END_OF_STACK:
  44                 return "end";
  45         case ORC_TYPE_CALL:
  46                 return "call";
  47         case ORC_TYPE_REGS:
  48                 return "regs";
  49         case ORC_TYPE_REGS_PARTIAL:
  50                 return "regs (partial)";
  51         default:
  52                 return "?";
  53         }
  54 }
  55
  56 static void print_reg(unsigned int reg, int offset)
  57 {
  58         if (reg == ORC_REG_BP_INDIRECT)
  59                 printf("(bp%+d)", offset);
  60         else if (reg == ORC_REG_SP_INDIRECT)
  61                 printf("(sp)%+d", offset);
  62         else if (reg == ORC_REG_UNDEFINED)
  63                 printf("(und)");
  64         else
  65                 printf("%s%+d", reg_name(reg), offset);
  66 }
  67
  68 int orc_dump(const char *_objname)
  69 {
  70         int fd, nr_entries, i, *orc_ip = NULL, orc_size = 0;
  71         struct orc_entry *orc = NULL;
  72         char *name;
  73         size_t nr_sections;
  74         Elf64_Addr orc_ip_addr = 0;
  75         size_t shstrtab_idx, strtab_idx = 0;
  76         Elf *elf;
  77         Elf_Scn *scn;
  78         GElf_Shdr sh;
  79         GElf_Rela rela;
  80         GElf_Sym sym;
  81         Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
  82         struct elf dummy_elf = {};
  83
  84
  85         objname = _objname;
  86
  87         elf_version(EV_CURRENT);
  88
  89         fd = open(objname, O_RDONLY);
  90         if (fd == -1) {
  91                 perror("open");
  92                 return -1;
  93         }
  94
  95         elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
  96         if (!elf) {
  97                 WARN_ELF("elf_begin");
  98                 return -1;
  99         }
 100
 101         if (!elf64_getehdr(elf)) {
 102                 WARN_ELF("elf64_getehdr");
 103                 return -1;
 104         }
 105         memcpy(&dummy_elf.ehdr, elf64_getehdr(elf), sizeof(dummy_elf.ehdr));
 106
 107         if (elf_getshdrnum(elf, &nr_sections)) {
 108                 WARN_ELF("elf_getshdrnum");
 109                 return -1;
 110         }
 111
 112         if (elf_getshdrstrndx(elf, &shstrtab_idx)) {
 113                 WARN_ELF("elf_getshdrstrndx");
 114                 return -1;
 115         }
 116
 117         for (i = 0; i < nr_sections; i++) {
 118                 scn = elf_getscn(elf, i);
 119                 if (!scn) {
 120                         WARN_ELF("elf_getscn");
 121                         return -1;
 122                 }
 123
 124                 if (!gelf_getshdr(scn, &sh)) {
 125                         WARN_ELF("gelf_getshdr");
 126                         return -1;
 127                 }
 128
 129                 name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
 130                 if (!name) {
 131                         WARN_ELF("elf_strptr");
 132                         return -1;
 133                 }
 134
 135                 data = elf_getdata(scn, NULL);
 136                 if (!data) {
 137                         WARN_ELF("elf_getdata");
 138                         return -1;
 139                 }
 140
 141                 if (!strcmp(name, ".symtab")) {
 142                         symtab = data;
 143                 } else if (!strcmp(name, ".strtab")) {
 144                         strtab_idx = i;
 145                 } else if (!strcmp(name, ".orc_unwind")) {
 146                         orc = data->d_buf;
 147                         orc_size = sh.sh_size;
 148                 } else if (!strcmp(name, ".orc_unwind_ip")) {
 149                         orc_ip = data->d_buf;
 150                         orc_ip_addr = sh.sh_addr;
 151                 } else if (!strcmp(name, ".rela.orc_unwind_ip")) {
 152                         rela_orc_ip = data;
 153                 }
 154         }
 155
 156         if (!symtab || !strtab_idx || !orc || !orc_ip)
 157                 return 0;
 158
 159         if (orc_size % sizeof(*orc) != 0) {
 160                 WARN("bad .orc_unwind section size");
 161                 return -1;
 162         }
 163
 164         nr_entries = orc_size / sizeof(*orc);
 165         for (i = 0; i < nr_entries; i++) {
 166                 if (rela_orc_ip) {
 167                         if (!gelf_getrela(rela_orc_ip, i, &rela)) {
 168                                 WARN_ELF("gelf_getrela");
 169                                 return -1;
 170                         }
 171
 172                         if (!gelf_getsym(symtab, GELF_R_SYM(rela.r_info), &sym)) {
 173                                 WARN_ELF("gelf_getsym");
 174                                 return -1;
 175                         }
 176
 177                         if (GELF_ST_TYPE(sym.st_info) == STT_SECTION) {
 178                                 scn = elf_getscn(elf, sym.st_shndx);
 179                                 if (!scn) {
 180                                         WARN_ELF("elf_getscn");
 181                                         return -1;
 182                                 }
 183
 184                                 if (!gelf_getshdr(scn, &sh)) {
 185                                         WARN_ELF("gelf_getshdr");
 186                                         return -1;
 187                                 }
 188
 189                                 name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
 190                                 if (!name) {
 191                                         WARN_ELF("elf_strptr");
 192                                         return -1;
 193                                 }
 194                         } else {
 195                                 name = elf_strptr(elf, strtab_idx, sym.st_name);
 196                                 if (!name) {
 197                                         WARN_ELF("elf_strptr");
 198                                         return -1;
 199                                 }
 200                         }
 201
 202                         printf("%s+%llx:", name, (unsigned long long)rela.r_addend);
 203
 204                 } else {
 205                         printf("%llx:", (unsigned long long)(orc_ip_addr + (i * sizeof(int)) + orc_ip[i]));
 206                 }
 207
 208                 printf("type:%s", orc_type_name(orc[i].type));
 209
 210                 printf(" sp:");
 211
 212                 print_reg(orc[i].sp_reg, bswap_if_needed(&dummy_elf, orc[i].sp_offset));
 213
 214                 printf(" bp:");
 215
 216                 print_reg(orc[i].bp_reg, bswap_if_needed(&dummy_elf, orc[i].bp_offset));
 217
 218                 printf(" signal:%d\n", orc[i].signal);
 219         }
 220
 221         elf_end(elf);
 222         close(fd);
 223
 224         return 0;
 225 }