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