1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * 4 * Copyright (C) 2017 Zihao Yu 5 */ 6 7 #include <linux/elf.h> 8 #include <linux/err.h> 9 #include <linux/errno.h> 10 #include <linux/moduleloader.h> 11 #include <linux/vmalloc.h> 12 #include <linux/sizes.h> 13 #include <linux/pgtable.h> 14 #include <asm/alternative.h> 15 #include <asm/sections.h> 16 17 /* 18 * The auipc+jalr instruction pair can reach any PC-relative offset 19 * in the range [-2^31 - 2^11, 2^31 - 2^11) 20 */ 21 static bool riscv_insn_valid_32bit_offset(ptrdiff_t val) 22 { 23 #ifdef CONFIG_32BIT 24 return true; 25 #else 26 return (-(1L << 31) - (1L << 11)) <= val && val < ((1L << 31) - (1L << 11)); 27 #endif 28 } 29 30 static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v) 31 { 32 if (v != (u32)v) { 33 pr_err("%s: value %016llx out of range for 32-bit field\n", 34 me->name, (long long)v); 35 return -EINVAL; 36 } 37 *location = v; 38 return 0; 39 } 40 41 static int apply_r_riscv_64_rela(struct module *me, u32 *location, Elf_Addr v) 42 { 43 *(u64 *)location = v; 44 return 0; 45 } 46 47 static int apply_r_riscv_branch_rela(struct module *me, u32 *location, 48 Elf_Addr v) 49 { 50 ptrdiff_t offset = (void *)v - (void *)location; 51 u32 imm12 = (offset & 0x1000) << (31 - 12); 52 u32 imm11 = (offset & 0x800) >> (11 - 7); 53 u32 imm10_5 = (offset & 0x7e0) << (30 - 10); 54 u32 imm4_1 = (offset & 0x1e) << (11 - 4); 55 56 *location = (*location & 0x1fff07f) | imm12 | imm11 | imm10_5 | imm4_1; 57 return 0; 58 } 59 60 static int apply_r_riscv_jal_rela(struct module *me, u32 *location, 61 Elf_Addr v) 62 { 63 ptrdiff_t offset = (void *)v - (void *)location; 64 u32 imm20 = (offset & 0x100000) << (31 - 20); 65 u32 imm19_12 = (offset & 0xff000); 66 u32 imm11 = (offset & 0x800) << (20 - 11); 67 u32 imm10_1 = (offset & 0x7fe) << (30 - 10); 68 69 *location = (*location & 0xfff) | imm20 | imm19_12 | imm11 | imm10_1; 70 return 0; 71 } 72 73 static int apply_r_riscv_rvc_branch_rela(struct module *me, u32 *location, 74 Elf_Addr v) 75 { 76 ptrdiff_t offset = (void *)v - (void *)location; 77 u16 imm8 = (offset & 0x100) << (12 - 8); 78 u16 imm7_6 = (offset & 0xc0) >> (6 - 5); 79 u16 imm5 = (offset & 0x20) >> (5 - 2); 80 u16 imm4_3 = (offset & 0x18) << (12 - 5); 81 u16 imm2_1 = (offset & 0x6) << (12 - 10); 82 83 *(u16 *)location = (*(u16 *)location & 0xe383) | 84 imm8 | imm7_6 | imm5 | imm4_3 | imm2_1; 85 return 0; 86 } 87 88 static int apply_r_riscv_rvc_jump_rela(struct module *me, u32 *location, 89 Elf_Addr v) 90 { 91 ptrdiff_t offset = (void *)v - (void *)location; 92 u16 imm11 = (offset & 0x800) << (12 - 11); 93 u16 imm10 = (offset & 0x400) >> (10 - 8); 94 u16 imm9_8 = (offset & 0x300) << (12 - 11); 95 u16 imm7 = (offset & 0x80) >> (7 - 6); 96 u16 imm6 = (offset & 0x40) << (12 - 11); 97 u16 imm5 = (offset & 0x20) >> (5 - 2); 98 u16 imm4 = (offset & 0x10) << (12 - 5); 99 u16 imm3_1 = (offset & 0xe) << (12 - 10); 100 101 *(u16 *)location = (*(u16 *)location & 0xe003) | 102 imm11 | imm10 | imm9_8 | imm7 | imm6 | imm5 | imm4 | imm3_1; 103 return 0; 104 } 105 106 static int apply_r_riscv_pcrel_hi20_rela(struct module *me, u32 *location, 107 Elf_Addr v) 108 { 109 ptrdiff_t offset = (void *)v - (void *)location; 110 s32 hi20; 111 112 if (!riscv_insn_valid_32bit_offset(offset)) { 113 pr_err( 114 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 115 me->name, (long long)v, location); 116 return -EINVAL; 117 } 118 119 hi20 = (offset + 0x800) & 0xfffff000; 120 *location = (*location & 0xfff) | hi20; 121 return 0; 122 } 123 124 static int apply_r_riscv_pcrel_lo12_i_rela(struct module *me, u32 *location, 125 Elf_Addr v) 126 { 127 /* 128 * v is the lo12 value to fill. It is calculated before calling this 129 * handler. 130 */ 131 *location = (*location & 0xfffff) | ((v & 0xfff) << 20); 132 return 0; 133 } 134 135 static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, u32 *location, 136 Elf_Addr v) 137 { 138 /* 139 * v is the lo12 value to fill. It is calculated before calling this 140 * handler. 141 */ 142 u32 imm11_5 = (v & 0xfe0) << (31 - 11); 143 u32 imm4_0 = (v & 0x1f) << (11 - 4); 144 145 *location = (*location & 0x1fff07f) | imm11_5 | imm4_0; 146 return 0; 147 } 148 149 static int apply_r_riscv_hi20_rela(struct module *me, u32 *location, 150 Elf_Addr v) 151 { 152 s32 hi20; 153 154 if (IS_ENABLED(CONFIG_CMODEL_MEDLOW)) { 155 pr_err( 156 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 157 me->name, (long long)v, location); 158 return -EINVAL; 159 } 160 161 hi20 = ((s32)v + 0x800) & 0xfffff000; 162 *location = (*location & 0xfff) | hi20; 163 return 0; 164 } 165 166 static int apply_r_riscv_lo12_i_rela(struct module *me, u32 *location, 167 Elf_Addr v) 168 { 169 /* Skip medlow checking because of filtering by HI20 already */ 170 s32 hi20 = ((s32)v + 0x800) & 0xfffff000; 171 s32 lo12 = ((s32)v - hi20); 172 *location = (*location & 0xfffff) | ((lo12 & 0xfff) << 20); 173 return 0; 174 } 175 176 static int apply_r_riscv_lo12_s_rela(struct module *me, u32 *location, 177 Elf_Addr v) 178 { 179 /* Skip medlow checking because of filtering by HI20 already */ 180 s32 hi20 = ((s32)v + 0x800) & 0xfffff000; 181 s32 lo12 = ((s32)v - hi20); 182 u32 imm11_5 = (lo12 & 0xfe0) << (31 - 11); 183 u32 imm4_0 = (lo12 & 0x1f) << (11 - 4); 184 *location = (*location & 0x1fff07f) | imm11_5 | imm4_0; 185 return 0; 186 } 187 188 static int apply_r_riscv_got_hi20_rela(struct module *me, u32 *location, 189 Elf_Addr v) 190 { 191 ptrdiff_t offset = (void *)v - (void *)location; 192 s32 hi20; 193 194 /* Always emit the got entry */ 195 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { 196 offset = module_emit_got_entry(me, v); 197 offset = (void *)offset - (void *)location; 198 } else { 199 pr_err( 200 "%s: can not generate the GOT entry for symbol = %016llx from PC = %p\n", 201 me->name, (long long)v, location); 202 return -EINVAL; 203 } 204 205 hi20 = (offset + 0x800) & 0xfffff000; 206 *location = (*location & 0xfff) | hi20; 207 return 0; 208 } 209 210 static int apply_r_riscv_call_plt_rela(struct module *me, u32 *location, 211 Elf_Addr v) 212 { 213 ptrdiff_t offset = (void *)v - (void *)location; 214 u32 hi20, lo12; 215 216 if (!riscv_insn_valid_32bit_offset(offset)) { 217 /* Only emit the plt entry if offset over 32-bit range */ 218 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { 219 offset = module_emit_plt_entry(me, v); 220 offset = (void *)offset - (void *)location; 221 } else { 222 pr_err( 223 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 224 me->name, (long long)v, location); 225 return -EINVAL; 226 } 227 } 228 229 hi20 = (offset + 0x800) & 0xfffff000; 230 lo12 = (offset - hi20) & 0xfff; 231 *location = (*location & 0xfff) | hi20; 232 *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20); 233 return 0; 234 } 235 236 static int apply_r_riscv_call_rela(struct module *me, u32 *location, 237 Elf_Addr v) 238 { 239 ptrdiff_t offset = (void *)v - (void *)location; 240 u32 hi20, lo12; 241 242 if (!riscv_insn_valid_32bit_offset(offset)) { 243 pr_err( 244 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 245 me->name, (long long)v, location); 246 return -EINVAL; 247 } 248 249 hi20 = (offset + 0x800) & 0xfffff000; 250 lo12 = (offset - hi20) & 0xfff; 251 *location = (*location & 0xfff) | hi20; 252 *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20); 253 return 0; 254 } 255 256 static int apply_r_riscv_relax_rela(struct module *me, u32 *location, 257 Elf_Addr v) 258 { 259 return 0; 260 } 261 262 static int apply_r_riscv_align_rela(struct module *me, u32 *location, 263 Elf_Addr v) 264 { 265 pr_err( 266 "%s: The unexpected relocation type 'R_RISCV_ALIGN' from PC = %p\n", 267 me->name, location); 268 return -EINVAL; 269 } 270 271 static int apply_r_riscv_add32_rela(struct module *me, u32 *location, 272 Elf_Addr v) 273 { 274 *(u32 *)location += (u32)v; 275 return 0; 276 } 277 278 static int apply_r_riscv_add64_rela(struct module *me, u32 *location, 279 Elf_Addr v) 280 { 281 *(u64 *)location += (u64)v; 282 return 0; 283 } 284 285 static int apply_r_riscv_sub32_rela(struct module *me, u32 *location, 286 Elf_Addr v) 287 { 288 *(u32 *)location -= (u32)v; 289 return 0; 290 } 291 292 static int apply_r_riscv_sub64_rela(struct module *me, u32 *location, 293 Elf_Addr v) 294 { 295 *(u64 *)location -= (u64)v; 296 return 0; 297 } 298 299 static int (*reloc_handlers_rela[]) (struct module *me, u32 *location, 300 Elf_Addr v) = { 301 [R_RISCV_32] = apply_r_riscv_32_rela, 302 [R_RISCV_64] = apply_r_riscv_64_rela, 303 [R_RISCV_BRANCH] = apply_r_riscv_branch_rela, 304 [R_RISCV_JAL] = apply_r_riscv_jal_rela, 305 [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela, 306 [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela, 307 [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela, 308 [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela, 309 [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela, 310 [R_RISCV_HI20] = apply_r_riscv_hi20_rela, 311 [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela, 312 [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela, 313 [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela, 314 [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela, 315 [R_RISCV_CALL] = apply_r_riscv_call_rela, 316 [R_RISCV_RELAX] = apply_r_riscv_relax_rela, 317 [R_RISCV_ALIGN] = apply_r_riscv_align_rela, 318 [R_RISCV_ADD32] = apply_r_riscv_add32_rela, 319 [R_RISCV_ADD64] = apply_r_riscv_add64_rela, 320 [R_RISCV_SUB32] = apply_r_riscv_sub32_rela, 321 [R_RISCV_SUB64] = apply_r_riscv_sub64_rela, 322 }; 323 324 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 325 unsigned int symindex, unsigned int relsec, 326 struct module *me) 327 { 328 Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr; 329 int (*handler)(struct module *me, u32 *location, Elf_Addr v); 330 Elf_Sym *sym; 331 u32 *location; 332 unsigned int i, type; 333 Elf_Addr v; 334 int res; 335 336 pr_debug("Applying relocate section %u to %u\n", relsec, 337 sechdrs[relsec].sh_info); 338 339 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 340 /* This is where to make the change */ 341 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 342 + rel[i].r_offset; 343 /* This is the symbol it is referring to */ 344 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 345 + ELF_RISCV_R_SYM(rel[i].r_info); 346 if (IS_ERR_VALUE(sym->st_value)) { 347 /* Ignore unresolved weak symbol */ 348 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 349 continue; 350 pr_warn("%s: Unknown symbol %s\n", 351 me->name, strtab + sym->st_name); 352 return -ENOENT; 353 } 354 355 type = ELF_RISCV_R_TYPE(rel[i].r_info); 356 357 if (type < ARRAY_SIZE(reloc_handlers_rela)) 358 handler = reloc_handlers_rela[type]; 359 else 360 handler = NULL; 361 362 if (!handler) { 363 pr_err("%s: Unknown relocation type %u\n", 364 me->name, type); 365 return -EINVAL; 366 } 367 368 v = sym->st_value + rel[i].r_addend; 369 370 if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) { 371 unsigned int j; 372 373 for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) { 374 unsigned long hi20_loc = 375 sechdrs[sechdrs[relsec].sh_info].sh_addr 376 + rel[j].r_offset; 377 u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info); 378 379 /* Find the corresponding HI20 relocation entry */ 380 if (hi20_loc == sym->st_value 381 && (hi20_type == R_RISCV_PCREL_HI20 382 || hi20_type == R_RISCV_GOT_HI20)) { 383 s32 hi20, lo12; 384 Elf_Sym *hi20_sym = 385 (Elf_Sym *)sechdrs[symindex].sh_addr 386 + ELF_RISCV_R_SYM(rel[j].r_info); 387 unsigned long hi20_sym_val = 388 hi20_sym->st_value 389 + rel[j].r_addend; 390 391 /* Calculate lo12 */ 392 size_t offset = hi20_sym_val - hi20_loc; 393 if (IS_ENABLED(CONFIG_MODULE_SECTIONS) 394 && hi20_type == R_RISCV_GOT_HI20) { 395 offset = module_emit_got_entry( 396 me, hi20_sym_val); 397 offset = offset - hi20_loc; 398 } 399 hi20 = (offset + 0x800) & 0xfffff000; 400 lo12 = offset - hi20; 401 v = lo12; 402 403 break; 404 } 405 } 406 if (j == sechdrs[relsec].sh_size / sizeof(*rel)) { 407 pr_err( 408 "%s: Can not find HI20 relocation information\n", 409 me->name); 410 return -EINVAL; 411 } 412 } 413 414 res = handler(me, location, v); 415 if (res) 416 return res; 417 } 418 419 return 0; 420 } 421 422 #if defined(CONFIG_MMU) && defined(CONFIG_64BIT) 423 void *module_alloc(unsigned long size) 424 { 425 return __vmalloc_node_range(size, 1, MODULES_VADDR, 426 MODULES_END, GFP_KERNEL, 427 PAGE_KERNEL, 0, NUMA_NO_NODE, 428 __builtin_return_address(0)); 429 } 430 #endif 431 432 static const Elf_Shdr *find_section(const Elf_Ehdr *hdr, 433 const Elf_Shdr *sechdrs, 434 const char *name) 435 { 436 const Elf_Shdr *s, *se; 437 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 438 439 for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) { 440 if (strcmp(name, secstrs + s->sh_name) == 0) 441 return s; 442 } 443 444 return NULL; 445 } 446 447 int module_finalize(const Elf_Ehdr *hdr, 448 const Elf_Shdr *sechdrs, 449 struct module *me) 450 { 451 const Elf_Shdr *s; 452 453 s = find_section(hdr, sechdrs, ".alternative"); 454 if (s) 455 apply_module_alternatives((void *)s->sh_addr, s->sh_size); 456 457 return 0; 458 } 459