tools/objtool/orc_dump.c

   1 /*
   2  * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <unistd.h>
  19 #include "orc.h"
  20 #include "warn.h"
  21
  22 static const char *reg_name(unsigned int reg)
  23 {
  24         switch (reg) {
  25         case ORC_REG_PREV_SP:
  26                 return "prevsp";
  27         case ORC_REG_DX:
  28                 return "dx";
  29         case ORC_REG_DI:
  30                 return "di";
  31         case ORC_REG_BP:
  32                 return "bp";
  33         case ORC_REG_SP:
  34                 return "sp";
  35         case ORC_REG_R10:
  36                 return "r10";
  37         case ORC_REG_R13:
  38                 return "r13";
  39         case ORC_REG_BP_INDIRECT:
  40                 return "bp(ind)";
  41         case ORC_REG_SP_INDIRECT:
  42                 return "sp(ind)";
  43         default:
  44                 return "?";
  45         }
  46 }
  47
  48 static const char *orc_type_name(unsigned int type)
  49 {
  50         switch (type) {
  51         case ORC_TYPE_CALL:
  52                 return "call";
  53         case ORC_TYPE_REGS:
  54                 return "regs";
  55         case ORC_TYPE_REGS_IRET:
  56                 return "iret";
  57         default:
  58                 return "?";
  59         }
  60 }
  61
  62 static void print_reg(unsigned int reg, int offset)
  63 {
  64         if (reg == ORC_REG_BP_INDIRECT)
  65                 printf("(bp%+d)", offset);
  66         else if (reg == ORC_REG_SP_INDIRECT)
  67                 printf("(sp%+d)", offset);
  68         else if (reg == ORC_REG_UNDEFINED)
  69                 printf("(und)");
  70         else
  71                 printf("%s%+d", reg_name(reg), offset);
  72 }
  73
  74 int orc_dump(const char *_objname)
  75 {
  76         int fd, nr_entries, i, *orc_ip = NULL, orc_size = 0;
  77         struct orc_entry *orc = NULL;
  78         char *name;
  79         unsigned long nr_sections, orc_ip_addr = 0;
  80         size_t shstrtab_idx;
  81         Elf *elf;
  82         Elf_Scn *scn;
  83         GElf_Shdr sh;
  84         GElf_Rela rela;
  85         GElf_Sym sym;
  86         Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
  87
  88
  89         objname = _objname;
  90
  91         elf_version(EV_CURRENT);
  92
  93         fd = open(objname, O_RDONLY);
  94         if (fd == -1) {
  95                 perror("open");
  96                 return -1;
  97         }
  98
  99         elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
 100         if (!elf) {
 101                 WARN_ELF("elf_begin");
 102                 return -1;
 103         }
 104
 105         if (elf_getshdrnum(elf, &nr_sections)) {
 106                 WARN_ELF("elf_getshdrnum");
 107                 return -1;
 108         }
 109
 110         if (elf_getshdrstrndx(elf, &shstrtab_idx)) {
 111                 WARN_ELF("elf_getshdrstrndx");
 112                 return -1;
 113         }
 114
 115         for (i = 0; i < nr_sections; i++) {
 116                 scn = elf_getscn(elf, i);
 117                 if (!scn) {
 118                         WARN_ELF("elf_getscn");
 119                         return -1;
 120                 }
 121
 122                 if (!gelf_getshdr(scn, &sh)) {
 123                         WARN_ELF("gelf_getshdr");
 124                         return -1;
 125                 }
 126
 127                 name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
 128                 if (!name) {
 129                         WARN_ELF("elf_strptr");
 130                         return -1;
 131                 }
 132
 133                 data = elf_getdata(scn, NULL);
 134                 if (!data) {
 135                         WARN_ELF("elf_getdata");
 136                         return -1;
 137                 }
 138
 139                 if (!strcmp(name, ".symtab")) {
 140                         symtab = data;
 141                 } else if (!strcmp(name, ".orc_unwind")) {
 142                         orc = data->d_buf;
 143                         orc_size = sh.sh_size;
 144                 } else if (!strcmp(name, ".orc_unwind_ip")) {
 145                         orc_ip = data->d_buf;
 146                         orc_ip_addr = sh.sh_addr;
 147                 } else if (!strcmp(name, ".rela.orc_unwind_ip")) {
 148                         rela_orc_ip = data;
 149                 }
 150         }
 151
 152         if (!symtab || !orc || !orc_ip)
 153                 return 0;
 154
 155         if (orc_size % sizeof(*orc) != 0) {
 156                 WARN("bad .orc_unwind section size");
 157                 return -1;
 158         }
 159
 160         nr_entries = orc_size / sizeof(*orc);
 161         for (i = 0; i < nr_entries; i++) {
 162                 if (rela_orc_ip) {
 163                         if (!gelf_getrela(rela_orc_ip, i, &rela)) {
 164                                 WARN_ELF("gelf_getrela");
 165                                 return -1;
 166                         }
 167
 168                         if (!gelf_getsym(symtab, GELF_R_SYM(rela.r_info), &sym)) {
 169                                 WARN_ELF("gelf_getsym");
 170                                 return -1;
 171                         }
 172
 173                         scn = elf_getscn(elf, sym.st_shndx);
 174                         if (!scn) {
 175                                 WARN_ELF("elf_getscn");
 176                                 return -1;
 177                         }
 178
 179                         if (!gelf_getshdr(scn, &sh)) {
 180                                 WARN_ELF("gelf_getshdr");
 181                                 return -1;
 182                         }
 183
 184                         name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
 185                         if (!name || !*name) {
 186                                 WARN_ELF("elf_strptr");
 187                                 return -1;
 188                         }
 189
 190                         printf("%s+%lx:", name, rela.r_addend);
 191
 192                 } else {
 193                         printf("%lx:", orc_ip_addr + (i * sizeof(int)) + orc_ip[i]);
 194                 }
 195
 196
 197                 printf(" sp:");
 198
 199                 print_reg(orc[i].sp_reg, orc[i].sp_offset);
 200
 201                 printf(" bp:");
 202
 203                 print_reg(orc[i].bp_reg, orc[i].bp_offset);
 204
 205                 printf(" type:%s\n", orc_type_name(orc[i].type));
 206         }
 207
 208         elf_end(elf);
 209         close(fd);
 210
 211         return 0;
 212 }