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/hashtable.h> 11 #include <linux/kernel.h> 12 #include <linux/log2.h> 13 #include <linux/moduleloader.h> 14 #include <linux/vmalloc.h> 15 #include <linux/sizes.h> 16 #include <linux/pgtable.h> 17 #include <asm/alternative.h> 18 #include <asm/sections.h> 19 20 struct used_bucket { 21 struct list_head head; 22 struct hlist_head *bucket; 23 }; 24 25 struct relocation_head { 26 struct hlist_node node; 27 struct list_head *rel_entry; 28 void *location; 29 }; 30 31 struct relocation_entry { 32 struct list_head head; 33 Elf_Addr value; 34 unsigned int type; 35 }; 36 37 struct relocation_handlers { 38 int (*reloc_handler)(struct module *me, void *location, Elf_Addr v); 39 int (*accumulate_handler)(struct module *me, void *location, 40 long buffer); 41 }; 42 43 unsigned int initialize_relocation_hashtable(unsigned int num_relocations); 44 void process_accumulated_relocations(struct module *me); 45 int add_relocation_to_accumulate(struct module *me, int type, void *location, 46 unsigned int hashtable_bits, Elf_Addr v); 47 48 struct hlist_head *relocation_hashtable; 49 50 struct list_head used_buckets_list; 51 52 /* 53 * The auipc+jalr instruction pair can reach any PC-relative offset 54 * in the range [-2^31 - 2^11, 2^31 - 2^11) 55 */ 56 static bool riscv_insn_valid_32bit_offset(ptrdiff_t val) 57 { 58 #ifdef CONFIG_32BIT 59 return true; 60 #else 61 return (-(1L << 31) - (1L << 11)) <= val && val < ((1L << 31) - (1L << 11)); 62 #endif 63 } 64 65 static int riscv_insn_rmw(void *location, u32 keep, u32 set) 66 { 67 u16 *parcel = location; 68 u32 insn = (u32)le16_to_cpu(parcel[0]) | (u32)le16_to_cpu(parcel[1]) << 16; 69 70 insn &= keep; 71 insn |= set; 72 73 parcel[0] = cpu_to_le16(insn); 74 parcel[1] = cpu_to_le16(insn >> 16); 75 return 0; 76 } 77 78 static int riscv_insn_rvc_rmw(void *location, u16 keep, u16 set) 79 { 80 u16 *parcel = location; 81 u16 insn = le16_to_cpu(*parcel); 82 83 insn &= keep; 84 insn |= set; 85 86 *parcel = cpu_to_le16(insn); 87 return 0; 88 } 89 90 static int apply_r_riscv_32_rela(struct module *me, void *location, Elf_Addr v) 91 { 92 if (v != (u32)v) { 93 pr_err("%s: value %016llx out of range for 32-bit field\n", 94 me->name, (long long)v); 95 return -EINVAL; 96 } 97 *(u32 *)location = v; 98 return 0; 99 } 100 101 static int apply_r_riscv_64_rela(struct module *me, void *location, Elf_Addr v) 102 { 103 *(u64 *)location = v; 104 return 0; 105 } 106 107 static int apply_r_riscv_branch_rela(struct module *me, void *location, 108 Elf_Addr v) 109 { 110 ptrdiff_t offset = (void *)v - location; 111 u32 imm12 = (offset & 0x1000) << (31 - 12); 112 u32 imm11 = (offset & 0x800) >> (11 - 7); 113 u32 imm10_5 = (offset & 0x7e0) << (30 - 10); 114 u32 imm4_1 = (offset & 0x1e) << (11 - 4); 115 116 return riscv_insn_rmw(location, 0x1fff07f, imm12 | imm11 | imm10_5 | imm4_1); 117 } 118 119 static int apply_r_riscv_jal_rela(struct module *me, void *location, 120 Elf_Addr v) 121 { 122 ptrdiff_t offset = (void *)v - location; 123 u32 imm20 = (offset & 0x100000) << (31 - 20); 124 u32 imm19_12 = (offset & 0xff000); 125 u32 imm11 = (offset & 0x800) << (20 - 11); 126 u32 imm10_1 = (offset & 0x7fe) << (30 - 10); 127 128 return riscv_insn_rmw(location, 0xfff, imm20 | imm19_12 | imm11 | imm10_1); 129 } 130 131 static int apply_r_riscv_rvc_branch_rela(struct module *me, void *location, 132 Elf_Addr v) 133 { 134 ptrdiff_t offset = (void *)v - location; 135 u16 imm8 = (offset & 0x100) << (12 - 8); 136 u16 imm7_6 = (offset & 0xc0) >> (6 - 5); 137 u16 imm5 = (offset & 0x20) >> (5 - 2); 138 u16 imm4_3 = (offset & 0x18) << (12 - 5); 139 u16 imm2_1 = (offset & 0x6) << (12 - 10); 140 141 return riscv_insn_rvc_rmw(location, 0xe383, 142 imm8 | imm7_6 | imm5 | imm4_3 | imm2_1); 143 } 144 145 static int apply_r_riscv_rvc_jump_rela(struct module *me, void *location, 146 Elf_Addr v) 147 { 148 ptrdiff_t offset = (void *)v - location; 149 u16 imm11 = (offset & 0x800) << (12 - 11); 150 u16 imm10 = (offset & 0x400) >> (10 - 8); 151 u16 imm9_8 = (offset & 0x300) << (12 - 11); 152 u16 imm7 = (offset & 0x80) >> (7 - 6); 153 u16 imm6 = (offset & 0x40) << (12 - 11); 154 u16 imm5 = (offset & 0x20) >> (5 - 2); 155 u16 imm4 = (offset & 0x10) << (12 - 5); 156 u16 imm3_1 = (offset & 0xe) << (12 - 10); 157 158 return riscv_insn_rvc_rmw(location, 0xe003, 159 imm11 | imm10 | imm9_8 | imm7 | imm6 | imm5 | imm4 | imm3_1); 160 } 161 162 static int apply_r_riscv_pcrel_hi20_rela(struct module *me, void *location, 163 Elf_Addr v) 164 { 165 ptrdiff_t offset = (void *)v - location; 166 167 if (!riscv_insn_valid_32bit_offset(offset)) { 168 pr_err( 169 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 170 me->name, (long long)v, location); 171 return -EINVAL; 172 } 173 174 return riscv_insn_rmw(location, 0xfff, (offset + 0x800) & 0xfffff000); 175 } 176 177 static int apply_r_riscv_pcrel_lo12_i_rela(struct module *me, void *location, 178 Elf_Addr v) 179 { 180 /* 181 * v is the lo12 value to fill. It is calculated before calling this 182 * handler. 183 */ 184 return riscv_insn_rmw(location, 0xfffff, (v & 0xfff) << 20); 185 } 186 187 static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, void *location, 188 Elf_Addr v) 189 { 190 /* 191 * v is the lo12 value to fill. It is calculated before calling this 192 * handler. 193 */ 194 u32 imm11_5 = (v & 0xfe0) << (31 - 11); 195 u32 imm4_0 = (v & 0x1f) << (11 - 4); 196 197 return riscv_insn_rmw(location, 0x1fff07f, imm11_5 | imm4_0); 198 } 199 200 static int apply_r_riscv_hi20_rela(struct module *me, void *location, 201 Elf_Addr v) 202 { 203 if (IS_ENABLED(CONFIG_CMODEL_MEDLOW)) { 204 pr_err( 205 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 206 me->name, (long long)v, location); 207 return -EINVAL; 208 } 209 210 return riscv_insn_rmw(location, 0xfff, ((s32)v + 0x800) & 0xfffff000); 211 } 212 213 static int apply_r_riscv_lo12_i_rela(struct module *me, void *location, 214 Elf_Addr v) 215 { 216 /* Skip medlow checking because of filtering by HI20 already */ 217 s32 hi20 = ((s32)v + 0x800) & 0xfffff000; 218 s32 lo12 = ((s32)v - hi20); 219 220 return riscv_insn_rmw(location, 0xfffff, (lo12 & 0xfff) << 20); 221 } 222 223 static int apply_r_riscv_lo12_s_rela(struct module *me, void *location, 224 Elf_Addr v) 225 { 226 /* Skip medlow checking because of filtering by HI20 already */ 227 s32 hi20 = ((s32)v + 0x800) & 0xfffff000; 228 s32 lo12 = ((s32)v - hi20); 229 u32 imm11_5 = (lo12 & 0xfe0) << (31 - 11); 230 u32 imm4_0 = (lo12 & 0x1f) << (11 - 4); 231 232 return riscv_insn_rmw(location, 0x1fff07f, imm11_5 | imm4_0); 233 } 234 235 static int apply_r_riscv_got_hi20_rela(struct module *me, void *location, 236 Elf_Addr v) 237 { 238 ptrdiff_t offset = (void *)v - location; 239 240 /* Always emit the got entry */ 241 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { 242 offset = (void *)module_emit_got_entry(me, v) - location; 243 } else { 244 pr_err( 245 "%s: can not generate the GOT entry for symbol = %016llx from PC = %p\n", 246 me->name, (long long)v, location); 247 return -EINVAL; 248 } 249 250 return riscv_insn_rmw(location, 0xfff, (offset + 0x800) & 0xfffff000); 251 } 252 253 static int apply_r_riscv_call_plt_rela(struct module *me, void *location, 254 Elf_Addr v) 255 { 256 ptrdiff_t offset = (void *)v - location; 257 u32 hi20, lo12; 258 259 if (!riscv_insn_valid_32bit_offset(offset)) { 260 /* Only emit the plt entry if offset over 32-bit range */ 261 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { 262 offset = (void *)module_emit_plt_entry(me, v) - location; 263 } else { 264 pr_err( 265 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 266 me->name, (long long)v, location); 267 return -EINVAL; 268 } 269 } 270 271 hi20 = (offset + 0x800) & 0xfffff000; 272 lo12 = (offset - hi20) & 0xfff; 273 riscv_insn_rmw(location, 0xfff, hi20); 274 return riscv_insn_rmw(location + 4, 0xfffff, lo12 << 20); 275 } 276 277 static int apply_r_riscv_call_rela(struct module *me, void *location, 278 Elf_Addr v) 279 { 280 ptrdiff_t offset = (void *)v - location; 281 u32 hi20, lo12; 282 283 if (!riscv_insn_valid_32bit_offset(offset)) { 284 pr_err( 285 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 286 me->name, (long long)v, location); 287 return -EINVAL; 288 } 289 290 hi20 = (offset + 0x800) & 0xfffff000; 291 lo12 = (offset - hi20) & 0xfff; 292 riscv_insn_rmw(location, 0xfff, hi20); 293 return riscv_insn_rmw(location + 4, 0xfffff, lo12 << 20); 294 } 295 296 static int apply_r_riscv_relax_rela(struct module *me, void *location, 297 Elf_Addr v) 298 { 299 return 0; 300 } 301 302 static int apply_r_riscv_align_rela(struct module *me, void *location, 303 Elf_Addr v) 304 { 305 pr_err( 306 "%s: The unexpected relocation type 'R_RISCV_ALIGN' from PC = %p\n", 307 me->name, location); 308 return -EINVAL; 309 } 310 311 static int apply_r_riscv_add8_rela(struct module *me, void *location, Elf_Addr v) 312 { 313 *(u8 *)location += (u8)v; 314 return 0; 315 } 316 317 static int apply_r_riscv_add16_rela(struct module *me, void *location, 318 Elf_Addr v) 319 { 320 *(u16 *)location += (u16)v; 321 return 0; 322 } 323 324 static int apply_r_riscv_add32_rela(struct module *me, void *location, 325 Elf_Addr v) 326 { 327 *(u32 *)location += (u32)v; 328 return 0; 329 } 330 331 static int apply_r_riscv_add64_rela(struct module *me, void *location, 332 Elf_Addr v) 333 { 334 *(u64 *)location += (u64)v; 335 return 0; 336 } 337 338 static int apply_r_riscv_sub8_rela(struct module *me, void *location, Elf_Addr v) 339 { 340 *(u8 *)location -= (u8)v; 341 return 0; 342 } 343 344 static int apply_r_riscv_sub16_rela(struct module *me, void *location, 345 Elf_Addr v) 346 { 347 *(u16 *)location -= (u16)v; 348 return 0; 349 } 350 351 static int apply_r_riscv_sub32_rela(struct module *me, void *location, 352 Elf_Addr v) 353 { 354 *(u32 *)location -= (u32)v; 355 return 0; 356 } 357 358 static int apply_r_riscv_sub64_rela(struct module *me, void *location, 359 Elf_Addr v) 360 { 361 *(u64 *)location -= (u64)v; 362 return 0; 363 } 364 365 static int dynamic_linking_not_supported(struct module *me, void *location, 366 Elf_Addr v) 367 { 368 pr_err("%s: Dynamic linking not supported in kernel modules PC = %p\n", 369 me->name, location); 370 return -EINVAL; 371 } 372 373 static int tls_not_supported(struct module *me, void *location, Elf_Addr v) 374 { 375 pr_err("%s: Thread local storage not supported in kernel modules PC = %p\n", 376 me->name, location); 377 return -EINVAL; 378 } 379 380 static int apply_r_riscv_sub6_rela(struct module *me, void *location, Elf_Addr v) 381 { 382 u8 *byte = location; 383 u8 value = v; 384 385 *byte = (*byte - (value & 0x3f)) & 0x3f; 386 return 0; 387 } 388 389 static int apply_r_riscv_set6_rela(struct module *me, void *location, Elf_Addr v) 390 { 391 u8 *byte = location; 392 u8 value = v; 393 394 *byte = (*byte & 0xc0) | (value & 0x3f); 395 return 0; 396 } 397 398 static int apply_r_riscv_set8_rela(struct module *me, void *location, Elf_Addr v) 399 { 400 *(u8 *)location = (u8)v; 401 return 0; 402 } 403 404 static int apply_r_riscv_set16_rela(struct module *me, void *location, 405 Elf_Addr v) 406 { 407 *(u16 *)location = (u16)v; 408 return 0; 409 } 410 411 static int apply_r_riscv_set32_rela(struct module *me, void *location, 412 Elf_Addr v) 413 { 414 *(u32 *)location = (u32)v; 415 return 0; 416 } 417 418 static int apply_r_riscv_32_pcrel_rela(struct module *me, void *location, 419 Elf_Addr v) 420 { 421 *(u32 *)location = v - (uintptr_t)location; 422 return 0; 423 } 424 425 static int apply_r_riscv_plt32_rela(struct module *me, void *location, 426 Elf_Addr v) 427 { 428 ptrdiff_t offset = (void *)v - location; 429 430 if (!riscv_insn_valid_32bit_offset(offset)) { 431 /* Only emit the plt entry if offset over 32-bit range */ 432 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { 433 offset = (void *)module_emit_plt_entry(me, v) - location; 434 } else { 435 pr_err("%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 436 me->name, (long long)v, location); 437 return -EINVAL; 438 } 439 } 440 441 *(u32 *)location = (u32)offset; 442 return 0; 443 } 444 445 static int apply_r_riscv_set_uleb128(struct module *me, void *location, Elf_Addr v) 446 { 447 *(long *)location = v; 448 return 0; 449 } 450 451 static int apply_r_riscv_sub_uleb128(struct module *me, void *location, Elf_Addr v) 452 { 453 *(long *)location -= v; 454 return 0; 455 } 456 457 static int apply_6_bit_accumulation(struct module *me, void *location, long buffer) 458 { 459 u8 *byte = location; 460 u8 value = buffer; 461 462 if (buffer > 0x3f) { 463 pr_err("%s: value %ld out of range for 6-bit relocation.\n", 464 me->name, buffer); 465 return -EINVAL; 466 } 467 468 *byte = (*byte & 0xc0) | (value & 0x3f); 469 return 0; 470 } 471 472 static int apply_8_bit_accumulation(struct module *me, void *location, long buffer) 473 { 474 if (buffer > U8_MAX) { 475 pr_err("%s: value %ld out of range for 8-bit relocation.\n", 476 me->name, buffer); 477 return -EINVAL; 478 } 479 *(u8 *)location = (u8)buffer; 480 return 0; 481 } 482 483 static int apply_16_bit_accumulation(struct module *me, void *location, long buffer) 484 { 485 if (buffer > U16_MAX) { 486 pr_err("%s: value %ld out of range for 16-bit relocation.\n", 487 me->name, buffer); 488 return -EINVAL; 489 } 490 *(u16 *)location = (u16)buffer; 491 return 0; 492 } 493 494 static int apply_32_bit_accumulation(struct module *me, void *location, long buffer) 495 { 496 if (buffer > U32_MAX) { 497 pr_err("%s: value %ld out of range for 32-bit relocation.\n", 498 me->name, buffer); 499 return -EINVAL; 500 } 501 *(u32 *)location = (u32)buffer; 502 return 0; 503 } 504 505 static int apply_64_bit_accumulation(struct module *me, void *location, long buffer) 506 { 507 *(u64 *)location = (u64)buffer; 508 return 0; 509 } 510 511 static int apply_uleb128_accumulation(struct module *me, void *location, long buffer) 512 { 513 /* 514 * ULEB128 is a variable length encoding. Encode the buffer into 515 * the ULEB128 data format. 516 */ 517 u8 *p = location; 518 519 while (buffer != 0) { 520 u8 value = buffer & 0x7f; 521 522 buffer >>= 7; 523 value |= (!!buffer) << 7; 524 525 *p++ = value; 526 } 527 return 0; 528 } 529 530 /* 531 * Relocations defined in the riscv-elf-psabi-doc. 532 * This handles static linking only. 533 */ 534 static const struct relocation_handlers reloc_handlers[] = { 535 [R_RISCV_32] = { .reloc_handler = apply_r_riscv_32_rela }, 536 [R_RISCV_64] = { .reloc_handler = apply_r_riscv_64_rela }, 537 [R_RISCV_RELATIVE] = { .reloc_handler = dynamic_linking_not_supported }, 538 [R_RISCV_COPY] = { .reloc_handler = dynamic_linking_not_supported }, 539 [R_RISCV_JUMP_SLOT] = { .reloc_handler = dynamic_linking_not_supported }, 540 [R_RISCV_TLS_DTPMOD32] = { .reloc_handler = dynamic_linking_not_supported }, 541 [R_RISCV_TLS_DTPMOD64] = { .reloc_handler = dynamic_linking_not_supported }, 542 [R_RISCV_TLS_DTPREL32] = { .reloc_handler = dynamic_linking_not_supported }, 543 [R_RISCV_TLS_DTPREL64] = { .reloc_handler = dynamic_linking_not_supported }, 544 [R_RISCV_TLS_TPREL32] = { .reloc_handler = dynamic_linking_not_supported }, 545 [R_RISCV_TLS_TPREL64] = { .reloc_handler = dynamic_linking_not_supported }, 546 /* 12-15 undefined */ 547 [R_RISCV_BRANCH] = { .reloc_handler = apply_r_riscv_branch_rela }, 548 [R_RISCV_JAL] = { .reloc_handler = apply_r_riscv_jal_rela }, 549 [R_RISCV_CALL] = { .reloc_handler = apply_r_riscv_call_rela }, 550 [R_RISCV_CALL_PLT] = { .reloc_handler = apply_r_riscv_call_plt_rela }, 551 [R_RISCV_GOT_HI20] = { .reloc_handler = apply_r_riscv_got_hi20_rela }, 552 [R_RISCV_TLS_GOT_HI20] = { .reloc_handler = tls_not_supported }, 553 [R_RISCV_TLS_GD_HI20] = { .reloc_handler = tls_not_supported }, 554 [R_RISCV_PCREL_HI20] = { .reloc_handler = apply_r_riscv_pcrel_hi20_rela }, 555 [R_RISCV_PCREL_LO12_I] = { .reloc_handler = apply_r_riscv_pcrel_lo12_i_rela }, 556 [R_RISCV_PCREL_LO12_S] = { .reloc_handler = apply_r_riscv_pcrel_lo12_s_rela }, 557 [R_RISCV_HI20] = { .reloc_handler = apply_r_riscv_hi20_rela }, 558 [R_RISCV_LO12_I] = { .reloc_handler = apply_r_riscv_lo12_i_rela }, 559 [R_RISCV_LO12_S] = { .reloc_handler = apply_r_riscv_lo12_s_rela }, 560 [R_RISCV_TPREL_HI20] = { .reloc_handler = tls_not_supported }, 561 [R_RISCV_TPREL_LO12_I] = { .reloc_handler = tls_not_supported }, 562 [R_RISCV_TPREL_LO12_S] = { .reloc_handler = tls_not_supported }, 563 [R_RISCV_TPREL_ADD] = { .reloc_handler = tls_not_supported }, 564 [R_RISCV_ADD8] = { .reloc_handler = apply_r_riscv_add8_rela, 565 .accumulate_handler = apply_8_bit_accumulation }, 566 [R_RISCV_ADD16] = { .reloc_handler = apply_r_riscv_add16_rela, 567 .accumulate_handler = apply_16_bit_accumulation }, 568 [R_RISCV_ADD32] = { .reloc_handler = apply_r_riscv_add32_rela, 569 .accumulate_handler = apply_32_bit_accumulation }, 570 [R_RISCV_ADD64] = { .reloc_handler = apply_r_riscv_add64_rela, 571 .accumulate_handler = apply_64_bit_accumulation }, 572 [R_RISCV_SUB8] = { .reloc_handler = apply_r_riscv_sub8_rela, 573 .accumulate_handler = apply_8_bit_accumulation }, 574 [R_RISCV_SUB16] = { .reloc_handler = apply_r_riscv_sub16_rela, 575 .accumulate_handler = apply_16_bit_accumulation }, 576 [R_RISCV_SUB32] = { .reloc_handler = apply_r_riscv_sub32_rela, 577 .accumulate_handler = apply_32_bit_accumulation }, 578 [R_RISCV_SUB64] = { .reloc_handler = apply_r_riscv_sub64_rela, 579 .accumulate_handler = apply_64_bit_accumulation }, 580 /* 41-42 reserved for future standard use */ 581 [R_RISCV_ALIGN] = { .reloc_handler = apply_r_riscv_align_rela }, 582 [R_RISCV_RVC_BRANCH] = { .reloc_handler = apply_r_riscv_rvc_branch_rela }, 583 [R_RISCV_RVC_JUMP] = { .reloc_handler = apply_r_riscv_rvc_jump_rela }, 584 /* 46-50 reserved for future standard use */ 585 [R_RISCV_RELAX] = { .reloc_handler = apply_r_riscv_relax_rela }, 586 [R_RISCV_SUB6] = { .reloc_handler = apply_r_riscv_sub6_rela, 587 .accumulate_handler = apply_6_bit_accumulation }, 588 [R_RISCV_SET6] = { .reloc_handler = apply_r_riscv_set6_rela, 589 .accumulate_handler = apply_6_bit_accumulation }, 590 [R_RISCV_SET8] = { .reloc_handler = apply_r_riscv_set8_rela, 591 .accumulate_handler = apply_8_bit_accumulation }, 592 [R_RISCV_SET16] = { .reloc_handler = apply_r_riscv_set16_rela, 593 .accumulate_handler = apply_16_bit_accumulation }, 594 [R_RISCV_SET32] = { .reloc_handler = apply_r_riscv_set32_rela, 595 .accumulate_handler = apply_32_bit_accumulation }, 596 [R_RISCV_32_PCREL] = { .reloc_handler = apply_r_riscv_32_pcrel_rela }, 597 [R_RISCV_IRELATIVE] = { .reloc_handler = dynamic_linking_not_supported }, 598 [R_RISCV_PLT32] = { .reloc_handler = apply_r_riscv_plt32_rela }, 599 [R_RISCV_SET_ULEB128] = { .reloc_handler = apply_r_riscv_set_uleb128, 600 .accumulate_handler = apply_uleb128_accumulation }, 601 [R_RISCV_SUB_ULEB128] = { .reloc_handler = apply_r_riscv_sub_uleb128, 602 .accumulate_handler = apply_uleb128_accumulation }, 603 /* 62-191 reserved for future standard use */ 604 /* 192-255 nonstandard ABI extensions */ 605 }; 606 607 void process_accumulated_relocations(struct module *me) 608 { 609 /* 610 * Only ADD/SUB/SET/ULEB128 should end up here. 611 * 612 * Each bucket may have more than one relocation location. All 613 * relocations for a location are stored in a list in a bucket. 614 * 615 * Relocations are applied to a temp variable before being stored to the 616 * provided location to check for overflow. This also allows ULEB128 to 617 * properly decide how many entries are needed before storing to 618 * location. The final value is stored into location using the handler 619 * for the last relocation to an address. 620 * 621 * Three layers of indexing: 622 * - Each of the buckets in use 623 * - Groups of relocations in each bucket by location address 624 * - Each relocation entry for a location address 625 */ 626 struct used_bucket *bucket_iter; 627 struct relocation_head *rel_head_iter; 628 struct relocation_entry *rel_entry_iter; 629 int curr_type; 630 void *location; 631 long buffer; 632 633 list_for_each_entry(bucket_iter, &used_buckets_list, head) { 634 hlist_for_each_entry(rel_head_iter, bucket_iter->bucket, node) { 635 buffer = 0; 636 location = rel_head_iter->location; 637 list_for_each_entry(rel_entry_iter, 638 rel_head_iter->rel_entry, head) { 639 curr_type = rel_entry_iter->type; 640 reloc_handlers[curr_type].reloc_handler( 641 me, &buffer, rel_entry_iter->value); 642 kfree(rel_entry_iter); 643 } 644 reloc_handlers[curr_type].accumulate_handler( 645 me, location, buffer); 646 kfree(rel_head_iter); 647 } 648 kfree(bucket_iter); 649 } 650 651 kfree(relocation_hashtable); 652 } 653 654 int add_relocation_to_accumulate(struct module *me, int type, void *location, 655 unsigned int hashtable_bits, Elf_Addr v) 656 { 657 struct relocation_entry *entry; 658 struct relocation_head *rel_head; 659 struct hlist_head *current_head; 660 struct used_bucket *bucket; 661 unsigned long hash; 662 663 entry = kmalloc(sizeof(*entry), GFP_KERNEL); 664 INIT_LIST_HEAD(&entry->head); 665 entry->type = type; 666 entry->value = v; 667 668 hash = hash_min((uintptr_t)location, hashtable_bits); 669 670 current_head = &relocation_hashtable[hash]; 671 672 /* Find matching location (if any) */ 673 bool found = false; 674 struct relocation_head *rel_head_iter; 675 676 hlist_for_each_entry(rel_head_iter, current_head, node) { 677 if (rel_head_iter->location == location) { 678 found = true; 679 rel_head = rel_head_iter; 680 break; 681 } 682 } 683 684 if (!found) { 685 rel_head = kmalloc(sizeof(*rel_head), GFP_KERNEL); 686 rel_head->rel_entry = 687 kmalloc(sizeof(struct list_head), GFP_KERNEL); 688 INIT_LIST_HEAD(rel_head->rel_entry); 689 rel_head->location = location; 690 INIT_HLIST_NODE(&rel_head->node); 691 if (!current_head->first) { 692 bucket = 693 kmalloc(sizeof(struct used_bucket), GFP_KERNEL); 694 INIT_LIST_HEAD(&bucket->head); 695 bucket->bucket = current_head; 696 list_add(&bucket->head, &used_buckets_list); 697 } 698 hlist_add_head(&rel_head->node, current_head); 699 } 700 701 /* Add relocation to head of discovered rel_head */ 702 list_add_tail(&entry->head, rel_head->rel_entry); 703 704 return 0; 705 } 706 707 unsigned int initialize_relocation_hashtable(unsigned int num_relocations) 708 { 709 /* Can safely assume that bits is not greater than sizeof(long) */ 710 unsigned long hashtable_size = roundup_pow_of_two(num_relocations); 711 unsigned int hashtable_bits = ilog2(hashtable_size); 712 713 /* 714 * Double size of hashtable if num_relocations * 1.25 is greater than 715 * hashtable_size. 716 */ 717 int should_double_size = ((num_relocations + (num_relocations >> 2)) > (hashtable_size)); 718 719 hashtable_bits += should_double_size; 720 721 hashtable_size <<= should_double_size; 722 723 relocation_hashtable = kmalloc_array(hashtable_size, 724 sizeof(*relocation_hashtable), 725 GFP_KERNEL); 726 __hash_init(relocation_hashtable, hashtable_size); 727 728 INIT_LIST_HEAD(&used_buckets_list); 729 730 return hashtable_bits; 731 } 732 733 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 734 unsigned int symindex, unsigned int relsec, 735 struct module *me) 736 { 737 Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr; 738 int (*handler)(struct module *me, void *location, Elf_Addr v); 739 Elf_Sym *sym; 740 void *location; 741 unsigned int i, type; 742 Elf_Addr v; 743 int res; 744 unsigned int num_relocations = sechdrs[relsec].sh_size / sizeof(*rel); 745 unsigned int hashtable_bits = initialize_relocation_hashtable(num_relocations); 746 747 pr_debug("Applying relocate section %u to %u\n", relsec, 748 sechdrs[relsec].sh_info); 749 750 for (i = 0; i < num_relocations; i++) { 751 /* This is where to make the change */ 752 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 753 + rel[i].r_offset; 754 /* This is the symbol it is referring to */ 755 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 756 + ELF_RISCV_R_SYM(rel[i].r_info); 757 if (IS_ERR_VALUE(sym->st_value)) { 758 /* Ignore unresolved weak symbol */ 759 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 760 continue; 761 pr_warn("%s: Unknown symbol %s\n", 762 me->name, strtab + sym->st_name); 763 return -ENOENT; 764 } 765 766 type = ELF_RISCV_R_TYPE(rel[i].r_info); 767 768 if (type < ARRAY_SIZE(reloc_handlers)) 769 handler = reloc_handlers[type].reloc_handler; 770 else 771 handler = NULL; 772 773 if (!handler) { 774 pr_err("%s: Unknown relocation type %u\n", 775 me->name, type); 776 return -EINVAL; 777 } 778 779 v = sym->st_value + rel[i].r_addend; 780 781 if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) { 782 unsigned int j; 783 784 for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) { 785 unsigned long hi20_loc = 786 sechdrs[sechdrs[relsec].sh_info].sh_addr 787 + rel[j].r_offset; 788 u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info); 789 790 /* Find the corresponding HI20 relocation entry */ 791 if (hi20_loc == sym->st_value 792 && (hi20_type == R_RISCV_PCREL_HI20 793 || hi20_type == R_RISCV_GOT_HI20)) { 794 s32 hi20, lo12; 795 Elf_Sym *hi20_sym = 796 (Elf_Sym *)sechdrs[symindex].sh_addr 797 + ELF_RISCV_R_SYM(rel[j].r_info); 798 unsigned long hi20_sym_val = 799 hi20_sym->st_value 800 + rel[j].r_addend; 801 802 /* Calculate lo12 */ 803 size_t offset = hi20_sym_val - hi20_loc; 804 if (IS_ENABLED(CONFIG_MODULE_SECTIONS) 805 && hi20_type == R_RISCV_GOT_HI20) { 806 offset = module_emit_got_entry( 807 me, hi20_sym_val); 808 offset = offset - hi20_loc; 809 } 810 hi20 = (offset + 0x800) & 0xfffff000; 811 lo12 = offset - hi20; 812 v = lo12; 813 814 break; 815 } 816 } 817 if (j == sechdrs[relsec].sh_size / sizeof(*rel)) { 818 pr_err( 819 "%s: Can not find HI20 relocation information\n", 820 me->name); 821 return -EINVAL; 822 } 823 } 824 825 if (reloc_handlers[type].accumulate_handler) 826 res = add_relocation_to_accumulate(me, type, location, hashtable_bits, v); 827 else 828 res = handler(me, location, v); 829 if (res) 830 return res; 831 } 832 833 process_accumulated_relocations(me); 834 835 return 0; 836 } 837 838 #if defined(CONFIG_MMU) && defined(CONFIG_64BIT) 839 void *module_alloc(unsigned long size) 840 { 841 return __vmalloc_node_range(size, 1, MODULES_VADDR, 842 MODULES_END, GFP_KERNEL, 843 PAGE_KERNEL, 0, NUMA_NO_NODE, 844 __builtin_return_address(0)); 845 } 846 #endif 847 848 int module_finalize(const Elf_Ehdr *hdr, 849 const Elf_Shdr *sechdrs, 850 struct module *me) 851 { 852 const Elf_Shdr *s; 853 854 s = find_section(hdr, sechdrs, ".alternative"); 855 if (s) 856 apply_module_alternatives((void *)s->sh_addr, s->sh_size); 857 858 return 0; 859 } 860