Patrick Georgi | 7333a11 | 2020-05-08 20:48:04 +0200 | [diff] [blame] | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 2 | |
Sol Boucher | 0e53931 | 2015-03-05 15:38:03 -0800 | [diff] [blame] | 3 | #include <inttypes.h> |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 4 | #include <stdio.h> |
| 5 | #include <stdlib.h> |
| 6 | #include <string.h> |
| 7 | |
| 8 | #include "elfparsing.h" |
| 9 | #include "rmodule.h" |
Aaron Durbin | dc9f5cd | 2015-09-08 13:34:43 -0500 | [diff] [blame] | 10 | #include <commonlib/rmodule-defs.h> |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 11 | |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 12 | /* |
| 13 | * Architecture specific support operations. |
| 14 | */ |
Sol Boucher | 0e53931 | 2015-03-05 15:38:03 -0800 | [diff] [blame] | 15 | static int valid_reloc_386(Elf64_Rela *rel) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 16 | { |
| 17 | int type; |
| 18 | |
| 19 | type = ELF64_R_TYPE(rel->r_info); |
| 20 | |
| 21 | /* Only these 2 relocations are expected to be found. */ |
| 22 | return (type == R_386_32 || type == R_386_PC32); |
| 23 | } |
| 24 | |
Sol Boucher | 0e53931 | 2015-03-05 15:38:03 -0800 | [diff] [blame] | 25 | static int should_emit_386(Elf64_Rela *rel) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 26 | { |
| 27 | int type; |
| 28 | |
| 29 | type = ELF64_R_TYPE(rel->r_info); |
| 30 | |
| 31 | /* R_386_32 relocations are absolute. Must emit these. */ |
| 32 | return (type == R_386_32); |
| 33 | } |
| 34 | |
Patrick Rudolph | 565bebe | 2018-11-26 15:54:21 +0100 | [diff] [blame] | 35 | static int valid_reloc_amd64(Elf64_Rela *rel) |
| 36 | { |
| 37 | int type; |
| 38 | |
| 39 | type = ELF64_R_TYPE(rel->r_info); |
| 40 | |
Patrick Rudolph | d023909 | 2021-06-11 21:24:10 +0200 | [diff] [blame] | 41 | /* |
| 42 | * Relocation R_AMD64_32S is not allowed. It can only be safely used in protected mode, |
| 43 | * and when the address pointed to is below 2 GiB in long mode. |
| 44 | * Using it in assembly operations will break compilation with error: |
| 45 | * E: Invalid reloc type: 11 |
| 46 | */ |
| 47 | |
| 48 | /* Only these 5 relocations are expected to be found. */ |
Patrick Rudolph | 565bebe | 2018-11-26 15:54:21 +0100 | [diff] [blame] | 49 | return (type == R_AMD64_64 || |
| 50 | type == R_AMD64_PC64 || |
Patrick Rudolph | 565bebe | 2018-11-26 15:54:21 +0100 | [diff] [blame] | 51 | type == R_AMD64_32 || |
Patrick Rudolph | 44b4ec7 | 2019-02-15 14:41:20 +0100 | [diff] [blame] | 52 | type == R_AMD64_PC32 || |
| 53 | /* |
| 54 | * binutils 2.31 introduced R_AMD64_PLT32 for non local |
| 55 | * functions. As we don't care about procedure linkage |
| 56 | * table entries handle it as R_X86_64_PC32. |
| 57 | */ |
| 58 | type == R_AMD64_PLT32); |
Patrick Rudolph | 565bebe | 2018-11-26 15:54:21 +0100 | [diff] [blame] | 59 | } |
| 60 | |
| 61 | static int should_emit_amd64(Elf64_Rela *rel) |
| 62 | { |
| 63 | int type; |
| 64 | |
| 65 | type = ELF64_R_TYPE(rel->r_info); |
| 66 | |
| 67 | /* Only emit absolute relocations */ |
| 68 | return (type == R_AMD64_64 || |
Patrick Rudolph | 565bebe | 2018-11-26 15:54:21 +0100 | [diff] [blame] | 69 | type == R_AMD64_32); |
| 70 | } |
| 71 | |
Sol Boucher | 0e53931 | 2015-03-05 15:38:03 -0800 | [diff] [blame] | 72 | static int valid_reloc_arm(Elf64_Rela *rel) |
Aaron Durbin | 785e47b | 2014-03-20 11:08:02 -0500 | [diff] [blame] | 73 | { |
| 74 | int type; |
| 75 | |
| 76 | type = ELF64_R_TYPE(rel->r_info); |
| 77 | |
Furquan Shaikh | c4f08f7 | 2014-07-23 13:42:22 -0700 | [diff] [blame] | 78 | /* Only these 6 relocations are expected to be found. */ |
Aaron Durbin | 785e47b | 2014-03-20 11:08:02 -0500 | [diff] [blame] | 79 | return (type == R_ARM_ABS32 || type == R_ARM_THM_PC22 || |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 80 | type == R_ARM_THM_JUMP24 || type == R_ARM_V4BX || |
Furquan Shaikh | c4f08f7 | 2014-07-23 13:42:22 -0700 | [diff] [blame] | 81 | type == R_ARM_CALL || type == R_ARM_JUMP24); |
Aaron Durbin | 785e47b | 2014-03-20 11:08:02 -0500 | [diff] [blame] | 82 | } |
| 83 | |
Sol Boucher | 0e53931 | 2015-03-05 15:38:03 -0800 | [diff] [blame] | 84 | static int should_emit_arm(Elf64_Rela *rel) |
Aaron Durbin | 785e47b | 2014-03-20 11:08:02 -0500 | [diff] [blame] | 85 | { |
| 86 | int type; |
| 87 | |
| 88 | type = ELF64_R_TYPE(rel->r_info); |
| 89 | |
| 90 | /* R_ARM_ABS32 relocations are absolute. Must emit these. */ |
| 91 | return (type == R_ARM_ABS32); |
| 92 | } |
| 93 | |
Sol Boucher | 0e53931 | 2015-03-05 15:38:03 -0800 | [diff] [blame] | 94 | static int valid_reloc_aarch64(Elf64_Rela *rel) |
Furquan Shaikh | d2338ba | 2014-08-26 15:21:15 -0700 | [diff] [blame] | 95 | { |
| 96 | int type; |
| 97 | |
| 98 | type = ELF64_R_TYPE(rel->r_info); |
| 99 | |
| 100 | return (type == R_AARCH64_ADR_PREL_PG_HI21 || |
| 101 | type == R_AARCH64_ADD_ABS_LO12_NC || |
Furquan Shaikh | de77e6a | 2014-11-21 15:41:10 -0800 | [diff] [blame] | 102 | type == R_AARCH64_LDST8_ABS_LO12_NC || |
Furquan Shaikh | 16c0a41 | 2015-06-08 11:58:04 -0700 | [diff] [blame] | 103 | type == R_AARCH64_CONDBR19 || |
Furquan Shaikh | d2338ba | 2014-08-26 15:21:15 -0700 | [diff] [blame] | 104 | type == R_AARCH64_JUMP26 || |
| 105 | type == R_AARCH64_LDST32_ABS_LO12_NC || |
Aaron Durbin | a47898e | 2014-09-18 13:39:16 -0500 | [diff] [blame] | 106 | type == R_AARCH64_LDST64_ABS_LO12_NC || |
Furquan Shaikh | d2338ba | 2014-08-26 15:21:15 -0700 | [diff] [blame] | 107 | type == R_AARCH64_CALL26 || |
| 108 | type == R_AARCH64_ABS64 || |
| 109 | type == R_AARCH64_LD_PREL_LO19 || |
| 110 | type == R_AARCH64_ADR_PREL_LO21); |
| 111 | } |
| 112 | |
Sol Boucher | 0e53931 | 2015-03-05 15:38:03 -0800 | [diff] [blame] | 113 | static int should_emit_aarch64(Elf64_Rela *rel) |
Furquan Shaikh | d2338ba | 2014-08-26 15:21:15 -0700 | [diff] [blame] | 114 | { |
| 115 | int type; |
| 116 | |
| 117 | type = ELF64_R_TYPE(rel->r_info); |
| 118 | |
| 119 | return (type == R_AARCH64_ABS64); |
| 120 | } |
| 121 | |
Aaron Durbin | b39a974 | 2015-09-08 17:24:04 -0500 | [diff] [blame] | 122 | static const struct arch_ops reloc_ops[] = { |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 123 | { |
| 124 | .arch = EM_386, |
| 125 | .valid_type = valid_reloc_386, |
| 126 | .should_emit = should_emit_386, |
| 127 | }, |
Aaron Durbin | 785e47b | 2014-03-20 11:08:02 -0500 | [diff] [blame] | 128 | { |
Patrick Rudolph | 565bebe | 2018-11-26 15:54:21 +0100 | [diff] [blame] | 129 | .arch = EM_X86_64, |
| 130 | .valid_type = valid_reloc_amd64, |
| 131 | .should_emit = should_emit_amd64, |
| 132 | }, |
| 133 | { |
Aaron Durbin | 785e47b | 2014-03-20 11:08:02 -0500 | [diff] [blame] | 134 | .arch = EM_ARM, |
| 135 | .valid_type = valid_reloc_arm, |
| 136 | .should_emit = should_emit_arm, |
| 137 | }, |
Furquan Shaikh | d2338ba | 2014-08-26 15:21:15 -0700 | [diff] [blame] | 138 | { |
| 139 | .arch = EM_AARCH64, |
| 140 | .valid_type = valid_reloc_aarch64, |
| 141 | .should_emit = should_emit_aarch64, |
| 142 | }, |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 143 | }; |
| 144 | |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 145 | static int relocation_for_absolute_symbol(struct rmod_context *ctx, Elf64_Rela *r) |
| 146 | { |
| 147 | Elf64_Sym *s = &ctx->pelf.syms[ELF64_R_SYM(r->r_info)]; |
| 148 | |
| 149 | if (s->st_shndx == SHN_ABS) { |
| 150 | DEBUG("Omitting relocation for absolute symbol: %s\n", |
| 151 | &ctx->strtab[s->st_name]); |
| 152 | return 1; |
| 153 | } |
| 154 | |
| 155 | return 0; |
| 156 | } |
| 157 | |
Raul E Rangel | 41ba01b | 2021-07-23 14:53:05 -0600 | [diff] [blame] | 158 | static int relocation_for_weak_extern_symbols(struct rmod_context *ctx, Elf64_Rela *r) |
| 159 | { |
| 160 | Elf64_Sym *s = &ctx->pelf.syms[ELF64_R_SYM(r->r_info)]; |
| 161 | |
| 162 | if (ELF64_ST_BIND(s->st_info) == STB_WEAK && ELF64_ST_TYPE(s->st_info) == STT_NOTYPE) { |
| 163 | DEBUG("Omitting relocation for undefined extern: %s\n", |
| 164 | &ctx->strtab[s->st_name]); |
| 165 | return 1; |
| 166 | } |
| 167 | |
| 168 | return 0; |
| 169 | } |
| 170 | |
Jeremy Compostella | 621ccf8 | 2023-09-07 20:26:56 -0700 | [diff] [blame] | 171 | static int relocation_for_undefined_symbol(struct rmod_context *ctx, Elf64_Rela *r) |
| 172 | { |
| 173 | Elf64_Sym *s = &ctx->pelf.syms[ELF64_R_SYM(r->r_info)]; |
| 174 | |
| 175 | if (s->st_shndx == SHN_UNDEF) { |
| 176 | DEBUG("Omitting relocation for undefined symbol: %s\n", |
| 177 | &ctx->strtab[s->st_name]); |
| 178 | return 1; |
| 179 | } |
| 180 | |
| 181 | return 0; |
| 182 | } |
| 183 | |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 184 | /* |
| 185 | * Relocation processing loops. |
| 186 | */ |
| 187 | |
Aaron Durbin | b39a974 | 2015-09-08 17:24:04 -0500 | [diff] [blame] | 188 | static int for_each_reloc(struct rmod_context *ctx, struct reloc_filter *f, |
| 189 | int do_emit) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 190 | { |
| 191 | Elf64_Half i; |
| 192 | struct parsed_elf *pelf = &ctx->pelf; |
| 193 | |
| 194 | for (i = 0; i < pelf->ehdr.e_shnum; i++) { |
| 195 | Elf64_Shdr *shdr; |
| 196 | Elf64_Rela *relocs; |
| 197 | Elf64_Xword nrelocs; |
| 198 | Elf64_Xword j; |
| 199 | |
| 200 | relocs = pelf->relocs[i]; |
| 201 | |
| 202 | /* No relocations in this section. */ |
| 203 | if (relocs == NULL) |
| 204 | continue; |
| 205 | |
| 206 | shdr = &pelf->shdr[i]; |
| 207 | nrelocs = shdr->sh_size / shdr->sh_entsize; |
| 208 | |
| 209 | for (j = 0; j < nrelocs; j++) { |
Aaron Durbin | b39a974 | 2015-09-08 17:24:04 -0500 | [diff] [blame] | 210 | int filter_emit = 1; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 211 | Elf64_Rela *r = &relocs[j]; |
| 212 | |
Sol Boucher | 0e53931 | 2015-03-05 15:38:03 -0800 | [diff] [blame] | 213 | if (!ctx->ops->valid_type(r)) { |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 214 | ERROR("Invalid reloc type: %u\n", |
| 215 | (unsigned int)ELF64_R_TYPE(r->r_info)); |
Patrick Rudolph | d023909 | 2021-06-11 21:24:10 +0200 | [diff] [blame] | 216 | if ((ctx->ops->arch == EM_X86_64) && |
| 217 | (ELF64_R_TYPE(r->r_info) == R_AMD64_32S)) |
| 218 | ERROR("Illegal use of 32bit sign extended addressing at offset 0x%x\n", |
| 219 | (unsigned int)r->r_offset); |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 220 | return -1; |
| 221 | } |
| 222 | |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 223 | if (relocation_for_absolute_symbol(ctx, r)) |
| 224 | continue; |
| 225 | |
Raul E Rangel | 41ba01b | 2021-07-23 14:53:05 -0600 | [diff] [blame] | 226 | if (relocation_for_weak_extern_symbols(ctx, r)) |
| 227 | continue; |
| 228 | |
Jeremy Compostella | 621ccf8 | 2023-09-07 20:26:56 -0700 | [diff] [blame] | 229 | if (relocation_for_undefined_symbol(ctx, r)) |
| 230 | continue; |
| 231 | |
Aaron Durbin | b39a974 | 2015-09-08 17:24:04 -0500 | [diff] [blame] | 232 | /* Allow the provided filter to have precedence. */ |
| 233 | if (f != NULL) { |
| 234 | filter_emit = f->filter(f, r); |
| 235 | |
| 236 | if (filter_emit < 0) |
| 237 | return filter_emit; |
| 238 | } |
| 239 | |
| 240 | if (filter_emit && ctx->ops->should_emit(r)) { |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 241 | int n = ctx->nrelocs; |
| 242 | if (do_emit) |
| 243 | ctx->emitted_relocs[n] = r->r_offset; |
| 244 | ctx->nrelocs++; |
| 245 | } |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | return 0; |
| 250 | } |
| 251 | |
| 252 | static int find_program_segment(struct rmod_context *ctx) |
| 253 | { |
| 254 | int i; |
| 255 | int nsegments; |
| 256 | struct parsed_elf *pelf; |
Anatol Pomozov | 8cce701 | 2015-07-10 17:30:01 -0700 | [diff] [blame] | 257 | Elf64_Phdr *phdr = NULL; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 258 | |
| 259 | pelf = &ctx->pelf; |
| 260 | |
| 261 | /* There should only be a single loadable segment. */ |
| 262 | nsegments = 0; |
| 263 | for (i = 0; i < pelf->ehdr.e_phnum; i++) { |
| 264 | if (pelf->phdr[i].p_type != PT_LOAD) |
| 265 | continue; |
Jeremy Compostella | 79f2e1f | 2023-08-30 15:35:46 -0700 | [diff] [blame] | 266 | if (!phdr) |
| 267 | phdr = &pelf->phdr[i]; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 268 | nsegments++; |
| 269 | } |
| 270 | |
Jeremy Compostella | 79f2e1f | 2023-08-30 15:35:46 -0700 | [diff] [blame] | 271 | if (nsegments == 0) { |
| 272 | ERROR("No loadable segment found.\n"); |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 273 | return -1; |
| 274 | } |
| 275 | |
| 276 | INFO("Segment at 0x%0llx, file size 0x%0llx, mem size 0x%0llx.\n", |
| 277 | (long long)phdr->p_vaddr, (long long)phdr->p_filesz, |
| 278 | (long long)phdr->p_memsz); |
| 279 | |
| 280 | ctx->phdr = phdr; |
Jeremy Compostella | 79f2e1f | 2023-08-30 15:35:46 -0700 | [diff] [blame] | 281 | ctx->nsegments = nsegments; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 282 | |
| 283 | return 0; |
| 284 | } |
| 285 | |
| 286 | static int |
| 287 | filter_relocation_sections(struct rmod_context *ctx) |
| 288 | { |
Jeremy Compostella | 79f2e1f | 2023-08-30 15:35:46 -0700 | [diff] [blame] | 289 | int i, j; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 290 | const char *shstrtab; |
| 291 | struct parsed_elf *pelf; |
| 292 | const Elf64_Phdr *phdr; |
| 293 | |
| 294 | pelf = &ctx->pelf; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 295 | shstrtab = buffer_get(pelf->strtabs[pelf->ehdr.e_shstrndx]); |
| 296 | |
| 297 | /* |
| 298 | * Find all relocation sections that contain relocation entries |
Jeremy Compostella | 79f2e1f | 2023-08-30 15:35:46 -0700 | [diff] [blame] | 299 | * for sections that fall within the bounds of the segments. For |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 300 | * easier processing the pointer to the relocation array for the |
| 301 | * sections that don't fall within the loadable program are NULL'd |
| 302 | * out. |
| 303 | */ |
| 304 | for (i = 0; i < pelf->ehdr.e_shnum; i++) { |
| 305 | Elf64_Shdr *shdr; |
| 306 | Elf64_Word sh_info; |
| 307 | const char *section_name; |
| 308 | |
| 309 | shdr = &pelf->shdr[i]; |
| 310 | |
| 311 | /* Ignore non-relocation sections. */ |
| 312 | if (shdr->sh_type != SHT_RELA && shdr->sh_type != SHT_REL) |
| 313 | continue; |
| 314 | |
| 315 | /* Obtain section which relocations apply. */ |
| 316 | sh_info = shdr->sh_info; |
| 317 | shdr = &pelf->shdr[sh_info]; |
| 318 | |
| 319 | section_name = &shstrtab[shdr->sh_name]; |
| 320 | DEBUG("Relocation section found for '%s' section.\n", |
| 321 | section_name); |
| 322 | |
| 323 | /* Do not process relocations for debug sections. */ |
| 324 | if (strstr(section_name, ".debug") != NULL) { |
| 325 | pelf->relocs[i] = NULL; |
| 326 | continue; |
| 327 | } |
| 328 | |
| 329 | /* |
| 330 | * If relocations apply to a non program section ignore the |
| 331 | * relocations for future processing. |
| 332 | */ |
| 333 | if (shdr->sh_type != SHT_PROGBITS) { |
| 334 | pelf->relocs[i] = NULL; |
| 335 | continue; |
| 336 | } |
| 337 | |
Jeremy Compostella | 79f2e1f | 2023-08-30 15:35:46 -0700 | [diff] [blame] | 338 | for (j = 0; j < pelf->ehdr.e_phnum; j++) { |
| 339 | phdr = &pelf->phdr[j]; |
| 340 | if (phdr->p_type == PT_LOAD && |
| 341 | shdr->sh_addr >= phdr->p_vaddr && |
| 342 | ((shdr->sh_addr + shdr->sh_size) <= |
| 343 | (phdr->p_vaddr + phdr->p_memsz))) |
| 344 | break; |
| 345 | } |
| 346 | if (j == pelf->ehdr.e_phnum) { |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 347 | ERROR("Relocations being applied to section %d not " |
Jeremy Compostella | 79f2e1f | 2023-08-30 15:35:46 -0700 | [diff] [blame] | 348 | "within segments region.\n", sh_info); |
| 349 | pelf->relocs[i] = NULL; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 350 | return -1; |
| 351 | } |
| 352 | } |
| 353 | |
| 354 | return 0; |
| 355 | } |
| 356 | |
| 357 | static int vaddr_cmp(const void *a, const void *b) |
| 358 | { |
| 359 | const Elf64_Addr *pa = a; |
| 360 | const Elf64_Addr *pb = b; |
| 361 | |
| 362 | if (*pa < *pb) |
| 363 | return -1; |
| 364 | if (*pa > *pb) |
| 365 | return 1; |
| 366 | return 0; |
| 367 | } |
| 368 | |
Aaron Durbin | b39a974 | 2015-09-08 17:24:04 -0500 | [diff] [blame] | 369 | int rmodule_collect_relocations(struct rmod_context *ctx, |
| 370 | struct reloc_filter *f) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 371 | { |
Sol Boucher | 0e53931 | 2015-03-05 15:38:03 -0800 | [diff] [blame] | 372 | Elf64_Xword nrelocs; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 373 | |
| 374 | /* |
| 375 | * The relocs array in the pelf should only contain relocations that |
| 376 | * apply to the program. Count the number relocations. Then collect |
| 377 | * them into the allocated buffer. |
| 378 | */ |
Aaron Durbin | b39a974 | 2015-09-08 17:24:04 -0500 | [diff] [blame] | 379 | if (for_each_reloc(ctx, f, 0)) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 380 | return -1; |
| 381 | |
| 382 | nrelocs = ctx->nrelocs; |
Sol Boucher | 0e53931 | 2015-03-05 15:38:03 -0800 | [diff] [blame] | 383 | INFO("%" PRIu64 " relocations to be emitted.\n", nrelocs); |
Furquan Shaikh | b237c10 | 2014-08-26 14:59:36 -0700 | [diff] [blame] | 384 | if (!nrelocs) |
| 385 | return 0; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 386 | |
| 387 | /* Reset the counter for indexing into the array. */ |
| 388 | ctx->nrelocs = 0; |
| 389 | ctx->emitted_relocs = calloc(nrelocs, sizeof(Elf64_Addr)); |
| 390 | /* Write out the relocations into the emitted_relocs array. */ |
Aaron Durbin | b39a974 | 2015-09-08 17:24:04 -0500 | [diff] [blame] | 391 | if (for_each_reloc(ctx, f, 1)) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 392 | return -1; |
| 393 | |
| 394 | if (ctx->nrelocs != nrelocs) { |
| 395 | ERROR("Mismatch counted and emitted relocations: %zu vs %zu.\n", |
| 396 | (size_t)nrelocs, (size_t)ctx->nrelocs); |
| 397 | return -1; |
| 398 | } |
| 399 | |
| 400 | /* Sort the relocations by their address. */ |
| 401 | qsort(ctx->emitted_relocs, nrelocs, sizeof(Elf64_Addr), vaddr_cmp); |
| 402 | |
| 403 | return 0; |
| 404 | } |
| 405 | |
| 406 | static int |
| 407 | populate_sym(struct rmod_context *ctx, const char *sym_name, Elf64_Addr *addr, |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 408 | int nsyms, int optional) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 409 | { |
| 410 | int i; |
| 411 | Elf64_Sym *syms; |
| 412 | |
| 413 | syms = ctx->pelf.syms; |
| 414 | |
| 415 | for (i = 0; i < nsyms; i++) { |
| 416 | if (syms[i].st_name == 0) |
| 417 | continue; |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 418 | if (strcmp(sym_name, &ctx->strtab[syms[i].st_name])) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 419 | continue; |
| 420 | DEBUG("%s -> 0x%llx\n", sym_name, (long long)syms[i].st_value); |
| 421 | *addr = syms[i].st_value; |
| 422 | return 0; |
| 423 | } |
Aaron Durbin | c9b053d | 2015-09-06 10:39:10 -0500 | [diff] [blame] | 424 | |
| 425 | if (optional) { |
| 426 | DEBUG("optional symbol '%s' not found.\n", sym_name); |
| 427 | *addr = 0; |
| 428 | return 0; |
| 429 | } |
| 430 | |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 431 | ERROR("symbol '%s' not found.\n", sym_name); |
| 432 | return -1; |
| 433 | } |
| 434 | |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 435 | static int populate_rmodule_info(struct rmod_context *ctx) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 436 | { |
| 437 | int i; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 438 | struct parsed_elf *pelf; |
| 439 | Elf64_Ehdr *ehdr; |
| 440 | int nsyms; |
| 441 | |
| 442 | pelf = &ctx->pelf; |
| 443 | ehdr = &pelf->ehdr; |
| 444 | |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 445 | /* Determine number of symbols. */ |
| 446 | nsyms = 0; |
| 447 | for (i = 0; i < ehdr->e_shnum; i++) { |
| 448 | if (pelf->shdr[i].sh_type != SHT_SYMTAB) |
| 449 | continue; |
| 450 | |
| 451 | nsyms = pelf->shdr[i].sh_size / pelf->shdr[i].sh_entsize; |
| 452 | break; |
| 453 | } |
| 454 | |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 455 | if (populate_sym(ctx, "_rmodule_params", &ctx->parameters_begin, nsyms, 1)) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 456 | return -1; |
| 457 | |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 458 | if (populate_sym(ctx, "_ermodule_params", &ctx->parameters_end, nsyms, 1)) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 459 | return -1; |
| 460 | |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 461 | if (populate_sym(ctx, "_bss", &ctx->bss_begin, nsyms, 0)) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 462 | return -1; |
| 463 | |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 464 | if (populate_sym(ctx, "_ebss", &ctx->bss_end, nsyms, 0)) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 465 | return -1; |
| 466 | |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 467 | return 0; |
| 468 | } |
| 469 | |
| 470 | static int |
| 471 | add_section(struct elf_writer *ew, struct buffer *data, const char *name, |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 472 | Elf64_Addr addr, Elf64_Word size) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 473 | { |
| 474 | Elf64_Shdr shdr; |
| 475 | int ret; |
| 476 | |
| 477 | memset(&shdr, 0, sizeof(shdr)); |
| 478 | if (data != NULL) { |
| 479 | shdr.sh_type = SHT_PROGBITS; |
| 480 | shdr.sh_flags = SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR; |
| 481 | } else { |
| 482 | shdr.sh_type = SHT_NOBITS; |
| 483 | shdr.sh_flags = SHF_ALLOC; |
| 484 | } |
| 485 | shdr.sh_addr = addr; |
| 486 | shdr.sh_offset = addr; |
| 487 | shdr.sh_size = size; |
| 488 | |
| 489 | ret = elf_writer_add_section(ew, &shdr, data, name); |
| 490 | |
| 491 | if (ret) |
| 492 | ERROR("Could not add '%s' section.\n", name); |
| 493 | |
| 494 | return ret; |
| 495 | } |
| 496 | |
| 497 | static int |
| 498 | write_elf(const struct rmod_context *ctx, const struct buffer *in, |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 499 | struct buffer *out) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 500 | { |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 501 | int ret; |
| 502 | int bit64; |
| 503 | size_t loc; |
| 504 | size_t rmod_data_size; |
| 505 | struct elf_writer *ew; |
| 506 | struct buffer rmod_data; |
| 507 | struct buffer rmod_header; |
| 508 | struct buffer program; |
| 509 | struct buffer relocs; |
| 510 | Elf64_Xword total_size; |
| 511 | Elf64_Addr addr; |
| 512 | Elf64_Ehdr ehdr; |
| 513 | |
Jeremy Compostella | 79f2e1f | 2023-08-30 15:35:46 -0700 | [diff] [blame] | 514 | if (ctx->nsegments != 1) { |
| 515 | ERROR("Multiple loadable segments is not supported.\n"); |
| 516 | return -1; |
| 517 | } |
| 518 | |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 519 | bit64 = ctx->pelf.ehdr.e_ident[EI_CLASS] == ELFCLASS64; |
| 520 | |
| 521 | /* |
| 522 | * 3 sections will be added to the ELF file. |
| 523 | * +------------------+ |
| 524 | * | rmodule header | |
| 525 | * +------------------+ |
| 526 | * | program | |
| 527 | * +------------------+ |
| 528 | * | relocations | |
| 529 | * +------------------+ |
| 530 | */ |
| 531 | |
| 532 | /* Create buffer for header and relocations. */ |
| 533 | rmod_data_size = sizeof(struct rmodule_header); |
| 534 | if (bit64) |
| 535 | rmod_data_size += ctx->nrelocs * sizeof(Elf64_Addr); |
| 536 | else |
| 537 | rmod_data_size += ctx->nrelocs * sizeof(Elf32_Addr); |
| 538 | |
| 539 | if (buffer_create(&rmod_data, rmod_data_size, "rmod")) |
| 540 | return -1; |
| 541 | |
| 542 | buffer_splice(&rmod_header, &rmod_data, |
| 543 | 0, sizeof(struct rmodule_header)); |
| 544 | buffer_clone(&relocs, &rmod_data); |
| 545 | buffer_seek(&relocs, sizeof(struct rmodule_header)); |
| 546 | |
| 547 | /* Reset current location. */ |
| 548 | buffer_set_size(&rmod_header, 0); |
| 549 | buffer_set_size(&relocs, 0); |
| 550 | |
| 551 | /* Program contents. */ |
| 552 | buffer_splice(&program, in, ctx->phdr->p_offset, ctx->phdr->p_filesz); |
| 553 | |
Julius Werner | 81dc20e | 2020-10-15 17:37:57 -0700 | [diff] [blame] | 554 | /* Create ELF writer. Set entry point to 0 to match section offsets. */ |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 555 | memcpy(&ehdr, &ctx->pelf.ehdr, sizeof(ehdr)); |
Julius Werner | 81dc20e | 2020-10-15 17:37:57 -0700 | [diff] [blame] | 556 | ehdr.e_entry = 0; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 557 | ew = elf_writer_init(&ehdr); |
| 558 | |
| 559 | if (ew == NULL) { |
| 560 | ERROR("Failed to create ELF writer.\n"); |
| 561 | buffer_delete(&rmod_data); |
| 562 | return -1; |
| 563 | } |
| 564 | |
| 565 | /* Write out rmodule_header. */ |
| 566 | ctx->xdr->put16(&rmod_header, RMODULE_MAGIC); |
| 567 | ctx->xdr->put8(&rmod_header, RMODULE_VERSION_1); |
| 568 | ctx->xdr->put8(&rmod_header, 0); |
| 569 | /* payload_begin_offset */ |
| 570 | loc = sizeof(struct rmodule_header); |
| 571 | ctx->xdr->put32(&rmod_header, loc); |
| 572 | /* payload_end_offset */ |
| 573 | loc += ctx->phdr->p_filesz; |
| 574 | ctx->xdr->put32(&rmod_header, loc); |
| 575 | /* relocations_begin_offset */ |
| 576 | ctx->xdr->put32(&rmod_header, loc); |
| 577 | /* relocations_end_offset */ |
| 578 | if (bit64) |
| 579 | loc += ctx->nrelocs * sizeof(Elf64_Addr); |
| 580 | else |
| 581 | loc += ctx->nrelocs * sizeof(Elf32_Addr); |
| 582 | ctx->xdr->put32(&rmod_header, loc); |
| 583 | /* module_link_start_address */ |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 584 | ctx->xdr->put32(&rmod_header, ctx->phdr->p_vaddr); |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 585 | /* module_program_size */ |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 586 | ctx->xdr->put32(&rmod_header, ctx->phdr->p_memsz); |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 587 | /* module_entry_point */ |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 588 | ctx->xdr->put32(&rmod_header, ctx->pelf.ehdr.e_entry); |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 589 | /* parameters_begin */ |
| 590 | ctx->xdr->put32(&rmod_header, ctx->parameters_begin); |
| 591 | /* parameters_end */ |
| 592 | ctx->xdr->put32(&rmod_header, ctx->parameters_end); |
| 593 | /* bss_begin */ |
| 594 | ctx->xdr->put32(&rmod_header, ctx->bss_begin); |
| 595 | /* bss_end */ |
| 596 | ctx->xdr->put32(&rmod_header, ctx->bss_end); |
| 597 | /* padding[4] */ |
| 598 | ctx->xdr->put32(&rmod_header, 0); |
| 599 | ctx->xdr->put32(&rmod_header, 0); |
| 600 | ctx->xdr->put32(&rmod_header, 0); |
| 601 | ctx->xdr->put32(&rmod_header, 0); |
| 602 | |
| 603 | /* Write the relocations. */ |
Sol Boucher | 0e53931 | 2015-03-05 15:38:03 -0800 | [diff] [blame] | 604 | for (unsigned i = 0; i < ctx->nrelocs; i++) { |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 605 | if (bit64) |
| 606 | ctx->xdr->put64(&relocs, ctx->emitted_relocs[i]); |
| 607 | else |
| 608 | ctx->xdr->put32(&relocs, ctx->emitted_relocs[i]); |
| 609 | } |
| 610 | |
| 611 | total_size = 0; |
| 612 | addr = 0; |
| 613 | |
| 614 | /* |
| 615 | * There are 2 cases to deal with. The program has a large NOBITS |
| 616 | * section and the relocations can fit entirely within occupied memory |
| 617 | * region for the program. The other is that the relocations increase |
| 618 | * the memory footprint of the program if it was loaded directly into |
Frans Hendriks | 166cbde | 2018-11-22 14:21:12 +0100 | [diff] [blame] | 619 | * the region it would run. The rmodule header is a fixed cost that |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 620 | * is considered a part of the program. |
| 621 | */ |
| 622 | total_size += buffer_size(&rmod_header); |
Aaron Durbin | 518a322 | 2014-08-26 13:52:30 -0500 | [diff] [blame] | 623 | if (buffer_size(&relocs) + ctx->phdr->p_filesz > ctx->phdr->p_memsz) { |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 624 | total_size += buffer_size(&relocs); |
| 625 | total_size += ctx->phdr->p_filesz; |
Aaron Durbin | 518a322 | 2014-08-26 13:52:30 -0500 | [diff] [blame] | 626 | } else { |
| 627 | total_size += ctx->phdr->p_memsz; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 628 | } |
| 629 | |
| 630 | ret = add_section(ew, &rmod_header, ".header", addr, |
| 631 | buffer_size(&rmod_header)); |
| 632 | if (ret < 0) |
| 633 | goto out; |
| 634 | addr += buffer_size(&rmod_header); |
| 635 | |
| 636 | ret = add_section(ew, &program, ".program", addr, ctx->phdr->p_filesz); |
| 637 | if (ret < 0) |
| 638 | goto out; |
| 639 | addr += ctx->phdr->p_filesz; |
| 640 | |
Furquan Shaikh | b237c10 | 2014-08-26 14:59:36 -0700 | [diff] [blame] | 641 | if (ctx->nrelocs) { |
| 642 | ret = add_section(ew, &relocs, ".relocs", addr, |
| 643 | buffer_size(&relocs)); |
| 644 | if (ret < 0) |
| 645 | goto out; |
| 646 | addr += buffer_size(&relocs); |
| 647 | } |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 648 | |
| 649 | if (total_size != addr) { |
| 650 | ret = add_section(ew, NULL, ".empty", addr, total_size - addr); |
| 651 | if (ret < 0) |
| 652 | goto out; |
| 653 | } |
| 654 | |
| 655 | /* |
| 656 | * Ensure last section has a memory usage that meets the required |
| 657 | * total size of the program in memory. |
| 658 | */ |
| 659 | |
| 660 | ret = elf_writer_serialize(ew, out); |
| 661 | if (ret < 0) |
| 662 | ERROR("Failed to serialize ELF to buffer.\n"); |
| 663 | |
| 664 | out: |
| 665 | buffer_delete(&rmod_data); |
| 666 | elf_writer_destroy(ew); |
| 667 | |
| 668 | return ret; |
| 669 | } |
| 670 | |
Aaron Durbin | b39a974 | 2015-09-08 17:24:04 -0500 | [diff] [blame] | 671 | int rmodule_init(struct rmod_context *ctx, const struct buffer *elfin) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 672 | { |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 673 | struct parsed_elf *pelf; |
Furquan Shaikh | 161d233 | 2016-05-26 14:41:02 -0700 | [diff] [blame] | 674 | size_t i; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 675 | int ret; |
| 676 | |
| 677 | ret = -1; |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 678 | memset(ctx, 0, sizeof(*ctx)); |
| 679 | pelf = &ctx->pelf; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 680 | |
| 681 | if (parse_elf(elfin, pelf, ELF_PARSE_ALL)) { |
| 682 | ERROR("Couldn't parse ELF!\n"); |
| 683 | return -1; |
| 684 | } |
| 685 | |
| 686 | /* Only allow executables to be turned into rmodules. */ |
| 687 | if (pelf->ehdr.e_type != ET_EXEC) { |
| 688 | ERROR("ELF is not an executable: %u.\n", pelf->ehdr.e_type); |
| 689 | goto out; |
| 690 | } |
| 691 | |
| 692 | /* Determine if architecture is supported. */ |
| 693 | for (i = 0; i < ARRAY_SIZE(reloc_ops); i++) { |
| 694 | if (reloc_ops[i].arch == pelf->ehdr.e_machine) { |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 695 | ctx->ops = &reloc_ops[i]; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 696 | break; |
| 697 | } |
| 698 | } |
| 699 | |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 700 | if (ctx->ops == NULL) { |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 701 | ERROR("ELF is unsupported arch: %u.\n", pelf->ehdr.e_machine); |
| 702 | goto out; |
| 703 | } |
| 704 | |
| 705 | /* Set the endian ops. */ |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 706 | if (ctx->pelf.ehdr.e_ident[EI_DATA] == ELFDATA2MSB) |
| 707 | ctx->xdr = &xdr_be; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 708 | else |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 709 | ctx->xdr = &xdr_le; |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 710 | |
Julius Werner | 84446e6 | 2021-02-12 17:37:27 -0800 | [diff] [blame] | 711 | /* Obtain the string table. */ |
| 712 | for (i = 0; i < pelf->ehdr.e_shnum; i++) { |
| 713 | if (pelf->strtabs[i] == NULL) |
| 714 | continue; |
| 715 | /* Don't use the section headers' string table. */ |
| 716 | if (i == pelf->ehdr.e_shstrndx) |
| 717 | continue; |
| 718 | ctx->strtab = buffer_get(pelf->strtabs[i]); |
| 719 | break; |
| 720 | } |
| 721 | |
| 722 | if (ctx->strtab == NULL) { |
| 723 | ERROR("No string table found.\n"); |
| 724 | return -1; |
| 725 | } |
| 726 | |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 727 | if (find_program_segment(ctx)) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 728 | goto out; |
| 729 | |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 730 | if (filter_relocation_sections(ctx)) |
| 731 | goto out; |
| 732 | |
| 733 | ret = 0; |
| 734 | |
| 735 | out: |
| 736 | return ret; |
| 737 | } |
| 738 | |
Aaron Durbin | b39a974 | 2015-09-08 17:24:04 -0500 | [diff] [blame] | 739 | void rmodule_cleanup(struct rmod_context *ctx) |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 740 | { |
| 741 | free(ctx->emitted_relocs); |
| 742 | parsed_elf_destroy(&ctx->pelf); |
| 743 | } |
| 744 | |
| 745 | int rmodule_create(const struct buffer *elfin, struct buffer *elfout) |
| 746 | { |
| 747 | struct rmod_context ctx; |
| 748 | int ret = -1; |
| 749 | |
| 750 | if (rmodule_init(&ctx, elfin)) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 751 | goto out; |
| 752 | |
Aaron Durbin | b39a974 | 2015-09-08 17:24:04 -0500 | [diff] [blame] | 753 | if (rmodule_collect_relocations(&ctx, NULL)) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 754 | goto out; |
| 755 | |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 756 | if (populate_rmodule_info(&ctx)) |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 757 | goto out; |
| 758 | |
| 759 | if (write_elf(&ctx, elfin, elfout)) |
| 760 | goto out; |
| 761 | |
| 762 | ret = 0; |
| 763 | |
| 764 | out: |
Aaron Durbin | 051a181 | 2015-09-08 15:52:01 -0500 | [diff] [blame] | 765 | rmodule_cleanup(&ctx); |
Aaron Durbin | 4fde5a6 | 2014-03-07 15:11:53 -0600 | [diff] [blame] | 766 | return ret; |
| 767 | } |
Aaron Durbin | 694fd13 | 2015-10-28 11:39:34 -0500 | [diff] [blame] | 768 | |
| 769 | static void rmod_deserialize(struct rmodule_header *rmod, struct buffer *buff, |
| 770 | struct xdr *xdr) |
| 771 | { |
| 772 | rmod->magic = xdr->get16(buff); |
| 773 | rmod->version = xdr->get8(buff); |
| 774 | rmod->type = xdr->get8(buff); |
| 775 | rmod->payload_begin_offset = xdr->get32(buff); |
| 776 | rmod->payload_end_offset = xdr->get32(buff); |
| 777 | rmod->relocations_begin_offset = xdr->get32(buff); |
| 778 | rmod->relocations_end_offset = xdr->get32(buff); |
| 779 | rmod->module_link_start_address = xdr->get32(buff); |
| 780 | rmod->module_program_size = xdr->get32(buff); |
| 781 | rmod->module_entry_point = xdr->get32(buff); |
| 782 | rmod->parameters_begin = xdr->get32(buff); |
| 783 | rmod->parameters_end = xdr->get32(buff); |
| 784 | rmod->bss_begin = xdr->get32(buff); |
| 785 | rmod->bss_end = xdr->get32(buff); |
| 786 | rmod->padding[0] = xdr->get32(buff); |
| 787 | rmod->padding[1] = xdr->get32(buff); |
| 788 | rmod->padding[2] = xdr->get32(buff); |
| 789 | rmod->padding[3] = xdr->get32(buff); |
| 790 | } |
| 791 | |
| 792 | int rmodule_stage_to_elf(Elf64_Ehdr *ehdr, struct buffer *buff) |
| 793 | { |
| 794 | struct buffer reader; |
| 795 | struct buffer elf_out; |
| 796 | struct rmodule_header rmod; |
| 797 | struct xdr *xdr; |
| 798 | struct elf_writer *ew; |
| 799 | Elf64_Shdr shdr; |
| 800 | int bit64; |
| 801 | size_t payload_sz; |
| 802 | const char *section_name = ".program"; |
| 803 | const size_t input_sz = buffer_size(buff); |
| 804 | |
| 805 | buffer_clone(&reader, buff); |
| 806 | |
| 807 | xdr = (ehdr->e_ident[EI_DATA] == ELFDATA2MSB) ? &xdr_be : &xdr_le; |
| 808 | bit64 = ehdr->e_ident[EI_CLASS] == ELFCLASS64; |
| 809 | |
| 810 | rmod_deserialize(&rmod, &reader, xdr); |
| 811 | |
| 812 | /* Indicate that file is not an rmodule if initial checks fail. */ |
| 813 | if (rmod.magic != RMODULE_MAGIC) |
| 814 | return 1; |
| 815 | if (rmod.version != RMODULE_VERSION_1) |
| 816 | return 1; |
| 817 | |
| 818 | if (rmod.payload_begin_offset > input_sz || |
| 819 | rmod.payload_end_offset > input_sz || |
| 820 | rmod.relocations_begin_offset > input_sz || |
| 821 | rmod.relocations_end_offset > input_sz) { |
| 822 | ERROR("Rmodule fields out of bounds.\n"); |
| 823 | return -1; |
| 824 | } |
| 825 | |
| 826 | ehdr->e_entry = rmod.module_entry_point; |
| 827 | ew = elf_writer_init(ehdr); |
| 828 | |
| 829 | if (ew == NULL) |
| 830 | return -1; |
| 831 | |
| 832 | payload_sz = rmod.payload_end_offset - rmod.payload_begin_offset; |
| 833 | memset(&shdr, 0, sizeof(shdr)); |
| 834 | shdr.sh_type = SHT_PROGBITS; |
| 835 | shdr.sh_flags = SHF_WRITE | SHF_ALLOC | SHF_EXECINSTR; |
| 836 | shdr.sh_addr = rmod.module_link_start_address; |
| 837 | shdr.sh_size = payload_sz; |
| 838 | buffer_splice(&reader, buff, rmod.payload_begin_offset, payload_sz); |
| 839 | |
| 840 | if (elf_writer_add_section(ew, &shdr, &reader, section_name)) { |
| 841 | ERROR("Unable to add ELF section: %s\n", section_name); |
| 842 | elf_writer_destroy(ew); |
| 843 | return -1; |
| 844 | } |
| 845 | |
| 846 | if (payload_sz != rmod.module_program_size) { |
| 847 | struct buffer b; |
| 848 | |
| 849 | buffer_init(&b, NULL, NULL, 0); |
| 850 | memset(&shdr, 0, sizeof(shdr)); |
| 851 | shdr.sh_type = SHT_NOBITS; |
| 852 | shdr.sh_flags = SHF_WRITE | SHF_ALLOC; |
| 853 | shdr.sh_addr = rmod.module_link_start_address + payload_sz; |
| 854 | shdr.sh_size = rmod.module_program_size - payload_sz; |
| 855 | if (elf_writer_add_section(ew, &shdr, &b, ".empty")) { |
| 856 | ERROR("Unable to add ELF section: .empty\n"); |
| 857 | elf_writer_destroy(ew); |
| 858 | return -1; |
| 859 | } |
| 860 | } |
| 861 | |
| 862 | /* Provide a section symbol so the relcoations can reference that. */ |
| 863 | if (elf_writer_add_symbol(ew, section_name, section_name, shdr.sh_addr, |
| 864 | 0, STB_LOCAL, STT_SECTION)) { |
| 865 | ERROR("Unable to add section symbol to ELF.\n"); |
| 866 | elf_writer_destroy(ew); |
| 867 | return -1; |
| 868 | } |
| 869 | |
| 870 | /* Add symbols for the parameters if they are non-zero. */ |
| 871 | if (rmod.parameters_begin != rmod.parameters_end) { |
| 872 | int ret = 0; |
| 873 | |
| 874 | ret |= elf_writer_add_symbol(ew, "_rmodule_params", |
| 875 | section_name, |
| 876 | rmod.parameters_begin, 0, |
| 877 | STB_GLOBAL, STT_NOTYPE); |
| 878 | ret |= elf_writer_add_symbol(ew, "_ermodule_params", |
| 879 | section_name, |
| 880 | rmod.parameters_end, 0, |
| 881 | STB_GLOBAL, STT_NOTYPE); |
| 882 | |
| 883 | if (ret != 0) { |
| 884 | ERROR("Unable to add module params symbols to ELF\n"); |
| 885 | elf_writer_destroy(ew); |
| 886 | return -1; |
| 887 | } |
| 888 | } |
| 889 | |
| 890 | if (elf_writer_add_symbol(ew, "_bss", section_name, rmod.bss_begin, 0, |
| 891 | STB_GLOBAL, STT_NOTYPE) || |
| 892 | elf_writer_add_symbol(ew, "_ebss", section_name, rmod.bss_end, 0, |
| 893 | STB_GLOBAL, STT_NOTYPE)) { |
| 894 | ERROR("Unable to add bss symbols to ELF\n"); |
| 895 | elf_writer_destroy(ew); |
| 896 | return -1; |
| 897 | } |
| 898 | |
| 899 | ssize_t relocs_sz = rmod.relocations_end_offset; |
| 900 | relocs_sz -= rmod.relocations_begin_offset; |
| 901 | buffer_splice(&reader, buff, rmod.relocations_begin_offset, relocs_sz); |
| 902 | while (relocs_sz > 0) { |
| 903 | Elf64_Addr addr; |
| 904 | |
| 905 | if (bit64) { |
| 906 | relocs_sz -= sizeof(Elf64_Addr); |
| 907 | addr = xdr->get64(&reader); |
| 908 | } else { |
| 909 | relocs_sz -= sizeof(Elf32_Addr); |
| 910 | addr = xdr->get32(&reader); |
| 911 | } |
| 912 | |
| 913 | /* Skip any relocations that are below the link address. */ |
| 914 | if (addr < rmod.module_link_start_address) |
| 915 | continue; |
| 916 | |
| 917 | if (elf_writer_add_rel(ew, section_name, addr)) { |
| 918 | ERROR("Relocation addition failure.\n"); |
| 919 | elf_writer_destroy(ew); |
| 920 | return -1; |
| 921 | } |
| 922 | } |
| 923 | |
| 924 | if (elf_writer_serialize(ew, &elf_out)) { |
| 925 | ERROR("ELF writer serialize failure.\n"); |
| 926 | elf_writer_destroy(ew); |
| 927 | return -1; |
| 928 | } |
| 929 | |
| 930 | elf_writer_destroy(ew); |
| 931 | |
| 932 | /* Flip buffer with the created ELF one. */ |
| 933 | buffer_delete(buff); |
| 934 | *buff = elf_out; |
| 935 | |
| 936 | return 0; |
| 937 | } |