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] = { apply_r_riscv_32_rela }, 536 [R_RISCV_64] = { apply_r_riscv_64_rela }, 537 [R_RISCV_RELATIVE] = { dynamic_linking_not_supported }, 538 [R_RISCV_COPY] = { dynamic_linking_not_supported }, 539 [R_RISCV_JUMP_SLOT] = { dynamic_linking_not_supported }, 540 [R_RISCV_TLS_DTPMOD32] = { dynamic_linking_not_supported }, 541 [R_RISCV_TLS_DTPMOD64] = { dynamic_linking_not_supported }, 542 [R_RISCV_TLS_DTPREL32] = { dynamic_linking_not_supported }, 543 [R_RISCV_TLS_DTPREL64] = { dynamic_linking_not_supported }, 544 [R_RISCV_TLS_TPREL32] = { dynamic_linking_not_supported }, 545 [R_RISCV_TLS_TPREL64] = { dynamic_linking_not_supported }, 546 /* 12-15 undefined */ 547 [R_RISCV_BRANCH] = { apply_r_riscv_branch_rela }, 548 [R_RISCV_JAL] = { apply_r_riscv_jal_rela }, 549 [R_RISCV_CALL] = { apply_r_riscv_call_rela }, 550 [R_RISCV_CALL_PLT] = { apply_r_riscv_call_plt_rela }, 551 [R_RISCV_GOT_HI20] = { apply_r_riscv_got_hi20_rela }, 552 [R_RISCV_TLS_GOT_HI20] = { tls_not_supported }, 553 [R_RISCV_TLS_GD_HI20] = { tls_not_supported }, 554 [R_RISCV_PCREL_HI20] = { apply_r_riscv_pcrel_hi20_rela }, 555 [R_RISCV_PCREL_LO12_I] = { apply_r_riscv_pcrel_lo12_i_rela }, 556 [R_RISCV_PCREL_LO12_S] = { apply_r_riscv_pcrel_lo12_s_rela }, 557 [R_RISCV_HI20] = { apply_r_riscv_hi20_rela }, 558 [R_RISCV_LO12_I] = { apply_r_riscv_lo12_i_rela }, 559 [R_RISCV_LO12_S] = { apply_r_riscv_lo12_s_rela }, 560 [R_RISCV_TPREL_HI20] = { tls_not_supported }, 561 [R_RISCV_TPREL_LO12_I] = { tls_not_supported }, 562 [R_RISCV_TPREL_LO12_S] = { tls_not_supported }, 563 [R_RISCV_TPREL_ADD] = { tls_not_supported }, 564 [R_RISCV_ADD8] = { apply_r_riscv_add8_rela, apply_8_bit_accumulation }, 565 [R_RISCV_ADD16] = { apply_r_riscv_add16_rela, 566 apply_16_bit_accumulation }, 567 [R_RISCV_ADD32] = { apply_r_riscv_add32_rela, 568 apply_32_bit_accumulation }, 569 [R_RISCV_ADD64] = { apply_r_riscv_add64_rela, 570 apply_64_bit_accumulation }, 571 [R_RISCV_SUB8] = { apply_r_riscv_sub8_rela, apply_8_bit_accumulation }, 572 [R_RISCV_SUB16] = { apply_r_riscv_sub16_rela, 573 apply_16_bit_accumulation }, 574 [R_RISCV_SUB32] = { apply_r_riscv_sub32_rela, 575 apply_32_bit_accumulation }, 576 [R_RISCV_SUB64] = { apply_r_riscv_sub64_rela, 577 apply_64_bit_accumulation }, 578 /* 41-42 reserved for future standard use */ 579 [R_RISCV_ALIGN] = { apply_r_riscv_align_rela }, 580 [R_RISCV_RVC_BRANCH] = { apply_r_riscv_rvc_branch_rela }, 581 [R_RISCV_RVC_JUMP] = { apply_r_riscv_rvc_jump_rela }, 582 /* 46-50 reserved for future standard use */ 583 [R_RISCV_RELAX] = { apply_r_riscv_relax_rela }, 584 [R_RISCV_SUB6] = { apply_r_riscv_sub6_rela, apply_6_bit_accumulation }, 585 [R_RISCV_SET6] = { apply_r_riscv_set6_rela, apply_6_bit_accumulation }, 586 [R_RISCV_SET8] = { apply_r_riscv_set8_rela, apply_8_bit_accumulation }, 587 [R_RISCV_SET16] = { apply_r_riscv_set16_rela, 588 apply_16_bit_accumulation }, 589 [R_RISCV_SET32] = { apply_r_riscv_set32_rela, 590 apply_32_bit_accumulation }, 591 [R_RISCV_32_PCREL] = { apply_r_riscv_32_pcrel_rela }, 592 [R_RISCV_IRELATIVE] = { dynamic_linking_not_supported }, 593 [R_RISCV_PLT32] = { apply_r_riscv_plt32_rela }, 594 [R_RISCV_SET_ULEB128] = { apply_r_riscv_set_uleb128, 595 apply_uleb128_accumulation }, 596 [R_RISCV_SUB_ULEB128] = { apply_r_riscv_sub_uleb128, 597 apply_uleb128_accumulation }, 598 /* 62-191 reserved for future standard use */ 599 /* 192-255 nonstandard ABI extensions */ 600 }; 601 602 void process_accumulated_relocations(struct module *me) 603 { 604 /* 605 * Only ADD/SUB/SET/ULEB128 should end up here. 606 * 607 * Each bucket may have more than one relocation location. All 608 * relocations for a location are stored in a list in a bucket. 609 * 610 * Relocations are applied to a temp variable before being stored to the 611 * provided location to check for overflow. This also allows ULEB128 to 612 * properly decide how many entries are needed before storing to 613 * location. The final value is stored into location using the handler 614 * for the last relocation to an address. 615 * 616 * Three layers of indexing: 617 * - Each of the buckets in use 618 * - Groups of relocations in each bucket by location address 619 * - Each relocation entry for a location address 620 */ 621 struct used_bucket *bucket_iter; 622 struct relocation_head *rel_head_iter; 623 struct relocation_entry *rel_entry_iter; 624 int curr_type; 625 void *location; 626 long buffer; 627 628 list_for_each_entry(bucket_iter, &used_buckets_list, head) { 629 hlist_for_each_entry(rel_head_iter, bucket_iter->bucket, node) { 630 buffer = 0; 631 location = rel_head_iter->location; 632 list_for_each_entry(rel_entry_iter, 633 rel_head_iter->rel_entry, head) { 634 curr_type = rel_entry_iter->type; 635 reloc_handlers[curr_type].reloc_handler( 636 me, &buffer, rel_entry_iter->value); 637 kfree(rel_entry_iter); 638 } 639 reloc_handlers[curr_type].accumulate_handler( 640 me, location, buffer); 641 kfree(rel_head_iter); 642 } 643 kfree(bucket_iter); 644 } 645 646 kfree(relocation_hashtable); 647 } 648 649 int add_relocation_to_accumulate(struct module *me, int type, void *location, 650 unsigned int hashtable_bits, Elf_Addr v) 651 { 652 struct relocation_entry *entry; 653 struct relocation_head *rel_head; 654 struct hlist_head *current_head; 655 struct used_bucket *bucket; 656 unsigned long hash; 657 658 entry = kmalloc(sizeof(*entry), GFP_KERNEL); 659 INIT_LIST_HEAD(&entry->head); 660 entry->type = type; 661 entry->value = v; 662 663 hash = hash_min((uintptr_t)location, hashtable_bits); 664 665 current_head = &relocation_hashtable[hash]; 666 667 /* Find matching location (if any) */ 668 bool found = false; 669 struct relocation_head *rel_head_iter; 670 671 hlist_for_each_entry(rel_head_iter, current_head, node) { 672 if (rel_head_iter->location == location) { 673 found = true; 674 rel_head = rel_head_iter; 675 break; 676 } 677 } 678 679 if (!found) { 680 rel_head = kmalloc(sizeof(*rel_head), GFP_KERNEL); 681 rel_head->rel_entry = 682 kmalloc(sizeof(struct list_head), GFP_KERNEL); 683 INIT_LIST_HEAD(rel_head->rel_entry); 684 rel_head->location = location; 685 INIT_HLIST_NODE(&rel_head->node); 686 if (!current_head->first) { 687 bucket = 688 kmalloc(sizeof(struct used_bucket), GFP_KERNEL); 689 INIT_LIST_HEAD(&bucket->head); 690 bucket->bucket = current_head; 691 list_add(&bucket->head, &used_buckets_list); 692 } 693 hlist_add_head(&rel_head->node, current_head); 694 } 695 696 /* Add relocation to head of discovered rel_head */ 697 list_add_tail(&entry->head, rel_head->rel_entry); 698 699 return 0; 700 } 701 702 unsigned int initialize_relocation_hashtable(unsigned int num_relocations) 703 { 704 /* Can safely assume that bits is not greater than sizeof(long) */ 705 unsigned long hashtable_size = roundup_pow_of_two(num_relocations); 706 unsigned int hashtable_bits = ilog2(hashtable_size); 707 708 /* 709 * Double size of hashtable if num_relocations * 1.25 is greater than 710 * hashtable_size. 711 */ 712 int should_double_size = ((num_relocations + (num_relocations >> 2)) > (hashtable_size)); 713 714 hashtable_bits += should_double_size; 715 716 hashtable_size <<= should_double_size; 717 718 relocation_hashtable = kmalloc_array(hashtable_size, 719 sizeof(*relocation_hashtable), 720 GFP_KERNEL); 721 __hash_init(relocation_hashtable, hashtable_size); 722 723 INIT_LIST_HEAD(&used_buckets_list); 724 725 return hashtable_bits; 726 } 727 728 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 729 unsigned int symindex, unsigned int relsec, 730 struct module *me) 731 { 732 Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr; 733 int (*handler)(struct module *me, void *location, Elf_Addr v); 734 Elf_Sym *sym; 735 void *location; 736 unsigned int i, type; 737 Elf_Addr v; 738 int res; 739 unsigned int num_relocations = sechdrs[relsec].sh_size / sizeof(*rel); 740 unsigned int hashtable_bits = initialize_relocation_hashtable(num_relocations); 741 742 pr_debug("Applying relocate section %u to %u\n", relsec, 743 sechdrs[relsec].sh_info); 744 745 for (i = 0; i < num_relocations; i++) { 746 /* This is where to make the change */ 747 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 748 + rel[i].r_offset; 749 /* This is the symbol it is referring to */ 750 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 751 + ELF_RISCV_R_SYM(rel[i].r_info); 752 if (IS_ERR_VALUE(sym->st_value)) { 753 /* Ignore unresolved weak symbol */ 754 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 755 continue; 756 pr_warn("%s: Unknown symbol %s\n", 757 me->name, strtab + sym->st_name); 758 return -ENOENT; 759 } 760 761 type = ELF_RISCV_R_TYPE(rel[i].r_info); 762 763 if (type < ARRAY_SIZE(reloc_handlers)) 764 handler = reloc_handlers[type].reloc_handler; 765 else 766 handler = NULL; 767 768 if (!handler) { 769 pr_err("%s: Unknown relocation type %u\n", 770 me->name, type); 771 return -EINVAL; 772 } 773 774 v = sym->st_value + rel[i].r_addend; 775 776 if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) { 777 unsigned int j; 778 779 for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) { 780 unsigned long hi20_loc = 781 sechdrs[sechdrs[relsec].sh_info].sh_addr 782 + rel[j].r_offset; 783 u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info); 784 785 /* Find the corresponding HI20 relocation entry */ 786 if (hi20_loc == sym->st_value 787 && (hi20_type == R_RISCV_PCREL_HI20 788 || hi20_type == R_RISCV_GOT_HI20)) { 789 s32 hi20, lo12; 790 Elf_Sym *hi20_sym = 791 (Elf_Sym *)sechdrs[symindex].sh_addr 792 + ELF_RISCV_R_SYM(rel[j].r_info); 793 unsigned long hi20_sym_val = 794 hi20_sym->st_value 795 + rel[j].r_addend; 796 797 /* Calculate lo12 */ 798 size_t offset = hi20_sym_val - hi20_loc; 799 if (IS_ENABLED(CONFIG_MODULE_SECTIONS) 800 && hi20_type == R_RISCV_GOT_HI20) { 801 offset = module_emit_got_entry( 802 me, hi20_sym_val); 803 offset = offset - hi20_loc; 804 } 805 hi20 = (offset + 0x800) & 0xfffff000; 806 lo12 = offset - hi20; 807 v = lo12; 808 809 break; 810 } 811 } 812 if (j == sechdrs[relsec].sh_size / sizeof(*rel)) { 813 pr_err( 814 "%s: Can not find HI20 relocation information\n", 815 me->name); 816 return -EINVAL; 817 } 818 } 819 820 if (reloc_handlers[type].accumulate_handler) 821 res = add_relocation_to_accumulate(me, type, location, hashtable_bits, v); 822 else 823 res = handler(me, location, v); 824 if (res) 825 return res; 826 } 827 828 process_accumulated_relocations(me); 829 830 return 0; 831 } 832 833 #if defined(CONFIG_MMU) && defined(CONFIG_64BIT) 834 void *module_alloc(unsigned long size) 835 { 836 return __vmalloc_node_range(size, 1, MODULES_VADDR, 837 MODULES_END, GFP_KERNEL, 838 PAGE_KERNEL, 0, NUMA_NO_NODE, 839 __builtin_return_address(0)); 840 } 841 #endif 842 843 int module_finalize(const Elf_Ehdr *hdr, 844 const Elf_Shdr *sechdrs, 845 struct module *me) 846 { 847 const Elf_Shdr *s; 848 849 s = find_section(hdr, sechdrs, ".alternative"); 850 if (s) 851 apply_module_alternatives((void *)s->sh_addr, s->sh_size); 852 853 return 0; 854 } 855