linux/tools/objtool/orc_dump.c
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   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
  22static 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
  48static 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
  62static 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
  74int 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        size_t nr_sections;
  80        Elf64_Addr orc_ip_addr = 0;
  81        size_t shstrtab_idx;
  82        Elf *elf;
  83        Elf_Scn *scn;
  84        GElf_Shdr sh;
  85        GElf_Rela rela;
  86        GElf_Sym sym;
  87        Elf_Data *data, *symtab = NULL, *rela_orc_ip = NULL;
  88
  89
  90        objname = _objname;
  91
  92        elf_version(EV_CURRENT);
  93
  94        fd = open(objname, O_RDONLY);
  95        if (fd == -1) {
  96                perror("open");
  97                return -1;
  98        }
  99
 100        elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
 101        if (!elf) {
 102                WARN_ELF("elf_begin");
 103                return -1;
 104        }
 105
 106        if (elf_getshdrnum(elf, &nr_sections)) {
 107                WARN_ELF("elf_getshdrnum");
 108                return -1;
 109        }
 110
 111        if (elf_getshdrstrndx(elf, &shstrtab_idx)) {
 112                WARN_ELF("elf_getshdrstrndx");
 113                return -1;
 114        }
 115
 116        for (i = 0; i < nr_sections; i++) {
 117                scn = elf_getscn(elf, i);
 118                if (!scn) {
 119                        WARN_ELF("elf_getscn");
 120                        return -1;
 121                }
 122
 123                if (!gelf_getshdr(scn, &sh)) {
 124                        WARN_ELF("gelf_getshdr");
 125                        return -1;
 126                }
 127
 128                name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
 129                if (!name) {
 130                        WARN_ELF("elf_strptr");
 131                        return -1;
 132                }
 133
 134                data = elf_getdata(scn, NULL);
 135                if (!data) {
 136                        WARN_ELF("elf_getdata");
 137                        return -1;
 138                }
 139
 140                if (!strcmp(name, ".symtab")) {
 141                        symtab = data;
 142                } else if (!strcmp(name, ".orc_unwind")) {
 143                        orc = data->d_buf;
 144                        orc_size = sh.sh_size;
 145                } else if (!strcmp(name, ".orc_unwind_ip")) {
 146                        orc_ip = data->d_buf;
 147                        orc_ip_addr = sh.sh_addr;
 148                } else if (!strcmp(name, ".rela.orc_unwind_ip")) {
 149                        rela_orc_ip = data;
 150                }
 151        }
 152
 153        if (!symtab || !orc || !orc_ip)
 154                return 0;
 155
 156        if (orc_size % sizeof(*orc) != 0) {
 157                WARN("bad .orc_unwind section size");
 158                return -1;
 159        }
 160
 161        nr_entries = orc_size / sizeof(*orc);
 162        for (i = 0; i < nr_entries; i++) {
 163                if (rela_orc_ip) {
 164                        if (!gelf_getrela(rela_orc_ip, i, &rela)) {
 165                                WARN_ELF("gelf_getrela");
 166                                return -1;
 167                        }
 168
 169                        if (!gelf_getsym(symtab, GELF_R_SYM(rela.r_info), &sym)) {
 170                                WARN_ELF("gelf_getsym");
 171                                return -1;
 172                        }
 173
 174                        scn = elf_getscn(elf, sym.st_shndx);
 175                        if (!scn) {
 176                                WARN_ELF("elf_getscn");
 177                                return -1;
 178                        }
 179
 180                        if (!gelf_getshdr(scn, &sh)) {
 181                                WARN_ELF("gelf_getshdr");
 182                                return -1;
 183                        }
 184
 185                        name = elf_strptr(elf, shstrtab_idx, sh.sh_name);
 186                        if (!name || !*name) {
 187                                WARN_ELF("elf_strptr");
 188                                return -1;
 189                        }
 190
 191                        printf("%s+%llx:", name, (unsigned long long)rela.r_addend);
 192
 193                } else {
 194                        printf("%llx:", (unsigned long long)(orc_ip_addr + (i * sizeof(int)) + orc_ip[i]));
 195                }
 196
 197
 198                printf(" sp:");
 199
 200                print_reg(orc[i].sp_reg, orc[i].sp_offset);
 201
 202                printf(" bp:");
 203
 204                print_reg(orc[i].bp_reg, orc[i].bp_offset);
 205
 206                printf(" type:%s\n", orc_type_name(orc[i].type));
 207        }
 208
 209        elf_end(elf);
 210        close(fd);
 211
 212        return 0;
 213}
 214