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