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 /* 44 * The auipc+jalr instruction pair can reach any PC-relative offset 45 * in the range [-2^31 - 2^11, 2^31 - 2^11) 46 */ 47 static bool riscv_insn_valid_32bit_offset(ptrdiff_t val) 48 { 49 #ifdef CONFIG_32BIT 50 return true; 51 #else 52 return (-(1L << 31) - (1L << 11)) <= val && val < ((1L << 31) - (1L << 11)); 53 #endif 54 } 55 56 static int riscv_insn_rmw(void *location, u32 keep, u32 set) 57 { 58 __le16 *parcel = location; 59 u32 insn = (u32)le16_to_cpu(parcel[0]) | (u32)le16_to_cpu(parcel[1]) << 16; 60 61 insn &= keep; 62 insn |= set; 63 64 parcel[0] = cpu_to_le16(insn); 65 parcel[1] = cpu_to_le16(insn >> 16); 66 return 0; 67 } 68 69 static int riscv_insn_rvc_rmw(void *location, u16 keep, u16 set) 70 { 71 __le16 *parcel = location; 72 u16 insn = le16_to_cpu(*parcel); 73 74 insn &= keep; 75 insn |= set; 76 77 *parcel = cpu_to_le16(insn); 78 return 0; 79 } 80 81 static int apply_r_riscv_32_rela(struct module *me, void *location, Elf_Addr v) 82 { 83 if (v != (u32)v) { 84 pr_err("%s: value %016llx out of range for 32-bit field\n", 85 me->name, (long long)v); 86 return -EINVAL; 87 } 88 *(u32 *)location = v; 89 return 0; 90 } 91 92 static int apply_r_riscv_64_rela(struct module *me, void *location, Elf_Addr v) 93 { 94 *(u64 *)location = v; 95 return 0; 96 } 97 98 static int apply_r_riscv_branch_rela(struct module *me, void *location, 99 Elf_Addr v) 100 { 101 ptrdiff_t offset = (void *)v - location; 102 u32 imm12 = (offset & 0x1000) << (31 - 12); 103 u32 imm11 = (offset & 0x800) >> (11 - 7); 104 u32 imm10_5 = (offset & 0x7e0) << (30 - 10); 105 u32 imm4_1 = (offset & 0x1e) << (11 - 4); 106 107 return riscv_insn_rmw(location, 0x1fff07f, imm12 | imm11 | imm10_5 | imm4_1); 108 } 109 110 static int apply_r_riscv_jal_rela(struct module *me, void *location, 111 Elf_Addr v) 112 { 113 ptrdiff_t offset = (void *)v - location; 114 u32 imm20 = (offset & 0x100000) << (31 - 20); 115 u32 imm19_12 = (offset & 0xff000); 116 u32 imm11 = (offset & 0x800) << (20 - 11); 117 u32 imm10_1 = (offset & 0x7fe) << (30 - 10); 118 119 return riscv_insn_rmw(location, 0xfff, imm20 | imm19_12 | imm11 | imm10_1); 120 } 121 122 static int apply_r_riscv_rvc_branch_rela(struct module *me, void *location, 123 Elf_Addr v) 124 { 125 ptrdiff_t offset = (void *)v - location; 126 u16 imm8 = (offset & 0x100) << (12 - 8); 127 u16 imm7_6 = (offset & 0xc0) >> (6 - 5); 128 u16 imm5 = (offset & 0x20) >> (5 - 2); 129 u16 imm4_3 = (offset & 0x18) << (12 - 5); 130 u16 imm2_1 = (offset & 0x6) << (12 - 10); 131 132 return riscv_insn_rvc_rmw(location, 0xe383, 133 imm8 | imm7_6 | imm5 | imm4_3 | imm2_1); 134 } 135 136 static int apply_r_riscv_rvc_jump_rela(struct module *me, void *location, 137 Elf_Addr v) 138 { 139 ptrdiff_t offset = (void *)v - location; 140 u16 imm11 = (offset & 0x800) << (12 - 11); 141 u16 imm10 = (offset & 0x400) >> (10 - 8); 142 u16 imm9_8 = (offset & 0x300) << (12 - 11); 143 u16 imm7 = (offset & 0x80) >> (7 - 6); 144 u16 imm6 = (offset & 0x40) << (12 - 11); 145 u16 imm5 = (offset & 0x20) >> (5 - 2); 146 u16 imm4 = (offset & 0x10) << (12 - 5); 147 u16 imm3_1 = (offset & 0xe) << (12 - 10); 148 149 return riscv_insn_rvc_rmw(location, 0xe003, 150 imm11 | imm10 | imm9_8 | imm7 | imm6 | imm5 | imm4 | imm3_1); 151 } 152 153 static int apply_r_riscv_pcrel_hi20_rela(struct module *me, void *location, 154 Elf_Addr v) 155 { 156 ptrdiff_t offset = (void *)v - location; 157 158 if (!riscv_insn_valid_32bit_offset(offset)) { 159 pr_err( 160 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 161 me->name, (long long)v, location); 162 return -EINVAL; 163 } 164 165 return riscv_insn_rmw(location, 0xfff, (offset + 0x800) & 0xfffff000); 166 } 167 168 static int apply_r_riscv_pcrel_lo12_i_rela(struct module *me, void *location, 169 Elf_Addr v) 170 { 171 /* 172 * v is the lo12 value to fill. It is calculated before calling this 173 * handler. 174 */ 175 return riscv_insn_rmw(location, 0xfffff, (v & 0xfff) << 20); 176 } 177 178 static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, void *location, 179 Elf_Addr v) 180 { 181 /* 182 * v is the lo12 value to fill. It is calculated before calling this 183 * handler. 184 */ 185 u32 imm11_5 = (v & 0xfe0) << (31 - 11); 186 u32 imm4_0 = (v & 0x1f) << (11 - 4); 187 188 return riscv_insn_rmw(location, 0x1fff07f, imm11_5 | imm4_0); 189 } 190 191 static int apply_r_riscv_hi20_rela(struct module *me, void *location, 192 Elf_Addr v) 193 { 194 if (IS_ENABLED(CONFIG_CMODEL_MEDLOW)) { 195 pr_err( 196 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 197 me->name, (long long)v, location); 198 return -EINVAL; 199 } 200 201 return riscv_insn_rmw(location, 0xfff, ((s32)v + 0x800) & 0xfffff000); 202 } 203 204 static int apply_r_riscv_lo12_i_rela(struct module *me, void *location, 205 Elf_Addr v) 206 { 207 /* Skip medlow checking because of filtering by HI20 already */ 208 s32 hi20 = ((s32)v + 0x800) & 0xfffff000; 209 s32 lo12 = ((s32)v - hi20); 210 211 return riscv_insn_rmw(location, 0xfffff, (lo12 & 0xfff) << 20); 212 } 213 214 static int apply_r_riscv_lo12_s_rela(struct module *me, void *location, 215 Elf_Addr v) 216 { 217 /* Skip medlow checking because of filtering by HI20 already */ 218 s32 hi20 = ((s32)v + 0x800) & 0xfffff000; 219 s32 lo12 = ((s32)v - hi20); 220 u32 imm11_5 = (lo12 & 0xfe0) << (31 - 11); 221 u32 imm4_0 = (lo12 & 0x1f) << (11 - 4); 222 223 return riscv_insn_rmw(location, 0x1fff07f, imm11_5 | imm4_0); 224 } 225 226 static int apply_r_riscv_got_hi20_rela(struct module *me, void *location, 227 Elf_Addr v) 228 { 229 ptrdiff_t offset = (void *)v - location; 230 231 /* Always emit the got entry */ 232 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { 233 offset = (void *)module_emit_got_entry(me, v) - location; 234 } else { 235 pr_err( 236 "%s: can not generate the GOT entry for symbol = %016llx from PC = %p\n", 237 me->name, (long long)v, location); 238 return -EINVAL; 239 } 240 241 return riscv_insn_rmw(location, 0xfff, (offset + 0x800) & 0xfffff000); 242 } 243 244 static int apply_r_riscv_call_plt_rela(struct module *me, void *location, 245 Elf_Addr v) 246 { 247 ptrdiff_t offset = (void *)v - location; 248 u32 hi20, lo12; 249 250 if (!riscv_insn_valid_32bit_offset(offset)) { 251 /* Only emit the plt entry if offset over 32-bit range */ 252 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { 253 offset = (void *)module_emit_plt_entry(me, v) - location; 254 } else { 255 pr_err( 256 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 257 me->name, (long long)v, location); 258 return -EINVAL; 259 } 260 } 261 262 hi20 = (offset + 0x800) & 0xfffff000; 263 lo12 = (offset - hi20) & 0xfff; 264 riscv_insn_rmw(location, 0xfff, hi20); 265 return riscv_insn_rmw(location + 4, 0xfffff, lo12 << 20); 266 } 267 268 static int apply_r_riscv_call_rela(struct module *me, void *location, 269 Elf_Addr v) 270 { 271 ptrdiff_t offset = (void *)v - location; 272 u32 hi20, lo12; 273 274 if (!riscv_insn_valid_32bit_offset(offset)) { 275 pr_err( 276 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 277 me->name, (long long)v, location); 278 return -EINVAL; 279 } 280 281 hi20 = (offset + 0x800) & 0xfffff000; 282 lo12 = (offset - hi20) & 0xfff; 283 riscv_insn_rmw(location, 0xfff, hi20); 284 return riscv_insn_rmw(location + 4, 0xfffff, lo12 << 20); 285 } 286 287 static int apply_r_riscv_relax_rela(struct module *me, void *location, 288 Elf_Addr v) 289 { 290 return 0; 291 } 292 293 static int apply_r_riscv_align_rela(struct module *me, void *location, 294 Elf_Addr v) 295 { 296 pr_err( 297 "%s: The unexpected relocation type 'R_RISCV_ALIGN' from PC = %p\n", 298 me->name, location); 299 return -EINVAL; 300 } 301 302 static int apply_r_riscv_add8_rela(struct module *me, void *location, Elf_Addr v) 303 { 304 *(u8 *)location += (u8)v; 305 return 0; 306 } 307 308 static int apply_r_riscv_add16_rela(struct module *me, void *location, 309 Elf_Addr v) 310 { 311 *(u16 *)location += (u16)v; 312 return 0; 313 } 314 315 static int apply_r_riscv_add32_rela(struct module *me, void *location, 316 Elf_Addr v) 317 { 318 *(u32 *)location += (u32)v; 319 return 0; 320 } 321 322 static int apply_r_riscv_add64_rela(struct module *me, void *location, 323 Elf_Addr v) 324 { 325 *(u64 *)location += (u64)v; 326 return 0; 327 } 328 329 static int apply_r_riscv_sub8_rela(struct module *me, void *location, Elf_Addr v) 330 { 331 *(u8 *)location -= (u8)v; 332 return 0; 333 } 334 335 static int apply_r_riscv_sub16_rela(struct module *me, void *location, 336 Elf_Addr v) 337 { 338 *(u16 *)location -= (u16)v; 339 return 0; 340 } 341 342 static int apply_r_riscv_sub32_rela(struct module *me, void *location, 343 Elf_Addr v) 344 { 345 *(u32 *)location -= (u32)v; 346 return 0; 347 } 348 349 static int apply_r_riscv_sub64_rela(struct module *me, void *location, 350 Elf_Addr v) 351 { 352 *(u64 *)location -= (u64)v; 353 return 0; 354 } 355 356 static int dynamic_linking_not_supported(struct module *me, void *location, 357 Elf_Addr v) 358 { 359 pr_err("%s: Dynamic linking not supported in kernel modules PC = %p\n", 360 me->name, location); 361 return -EINVAL; 362 } 363 364 static int tls_not_supported(struct module *me, void *location, Elf_Addr v) 365 { 366 pr_err("%s: Thread local storage not supported in kernel modules PC = %p\n", 367 me->name, location); 368 return -EINVAL; 369 } 370 371 static int apply_r_riscv_sub6_rela(struct module *me, void *location, Elf_Addr v) 372 { 373 u8 *byte = location; 374 u8 value = v; 375 376 *byte = (*byte - (value & 0x3f)) & 0x3f; 377 return 0; 378 } 379 380 static int apply_r_riscv_set6_rela(struct module *me, void *location, Elf_Addr v) 381 { 382 u8 *byte = location; 383 u8 value = v; 384 385 *byte = (*byte & 0xc0) | (value & 0x3f); 386 return 0; 387 } 388 389 static int apply_r_riscv_set8_rela(struct module *me, void *location, Elf_Addr v) 390 { 391 *(u8 *)location = (u8)v; 392 return 0; 393 } 394 395 static int apply_r_riscv_set16_rela(struct module *me, void *location, 396 Elf_Addr v) 397 { 398 *(u16 *)location = (u16)v; 399 return 0; 400 } 401 402 static int apply_r_riscv_set32_rela(struct module *me, void *location, 403 Elf_Addr v) 404 { 405 *(u32 *)location = (u32)v; 406 return 0; 407 } 408 409 static int apply_r_riscv_32_pcrel_rela(struct module *me, void *location, 410 Elf_Addr v) 411 { 412 *(u32 *)location = v - (uintptr_t)location; 413 return 0; 414 } 415 416 static int apply_r_riscv_plt32_rela(struct module *me, void *location, 417 Elf_Addr v) 418 { 419 ptrdiff_t offset = (void *)v - location; 420 421 if (!riscv_insn_valid_32bit_offset(offset)) { 422 /* Only emit the plt entry if offset over 32-bit range */ 423 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) { 424 offset = (void *)module_emit_plt_entry(me, v) - location; 425 } else { 426 pr_err("%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n", 427 me->name, (long long)v, location); 428 return -EINVAL; 429 } 430 } 431 432 *(u32 *)location = (u32)offset; 433 return 0; 434 } 435 436 static int apply_r_riscv_set_uleb128(struct module *me, void *location, Elf_Addr v) 437 { 438 *(long *)location = v; 439 return 0; 440 } 441 442 static int apply_r_riscv_sub_uleb128(struct module *me, void *location, Elf_Addr v) 443 { 444 *(long *)location -= v; 445 return 0; 446 } 447 448 static int apply_6_bit_accumulation(struct module *me, void *location, long buffer) 449 { 450 u8 *byte = location; 451 u8 value = buffer; 452 453 if (buffer > 0x3f) { 454 pr_err("%s: value %ld out of range for 6-bit relocation.\n", 455 me->name, buffer); 456 return -EINVAL; 457 } 458 459 *byte = (*byte & 0xc0) | (value & 0x3f); 460 return 0; 461 } 462 463 static int apply_8_bit_accumulation(struct module *me, void *location, long buffer) 464 { 465 if (buffer > U8_MAX) { 466 pr_err("%s: value %ld out of range for 8-bit relocation.\n", 467 me->name, buffer); 468 return -EINVAL; 469 } 470 *(u8 *)location = (u8)buffer; 471 return 0; 472 } 473 474 static int apply_16_bit_accumulation(struct module *me, void *location, long buffer) 475 { 476 if (buffer > U16_MAX) { 477 pr_err("%s: value %ld out of range for 16-bit relocation.\n", 478 me->name, buffer); 479 return -EINVAL; 480 } 481 *(u16 *)location = (u16)buffer; 482 return 0; 483 } 484 485 static int apply_32_bit_accumulation(struct module *me, void *location, long buffer) 486 { 487 if (buffer > U32_MAX) { 488 pr_err("%s: value %ld out of range for 32-bit relocation.\n", 489 me->name, buffer); 490 return -EINVAL; 491 } 492 *(u32 *)location = (u32)buffer; 493 return 0; 494 } 495 496 static int apply_64_bit_accumulation(struct module *me, void *location, long buffer) 497 { 498 *(u64 *)location = (u64)buffer; 499 return 0; 500 } 501 502 static int apply_uleb128_accumulation(struct module *me, void *location, long buffer) 503 { 504 /* 505 * ULEB128 is a variable length encoding. Encode the buffer into 506 * the ULEB128 data format. 507 */ 508 u8 *p = location; 509 510 while (buffer != 0) { 511 u8 value = buffer & 0x7f; 512 513 buffer >>= 7; 514 value |= (!!buffer) << 7; 515 516 *p++ = value; 517 } 518 return 0; 519 } 520 521 /* 522 * Relocations defined in the riscv-elf-psabi-doc. 523 * This handles static linking only. 524 */ 525 static const struct relocation_handlers reloc_handlers[] = { 526 [R_RISCV_32] = { .reloc_handler = apply_r_riscv_32_rela }, 527 [R_RISCV_64] = { .reloc_handler = apply_r_riscv_64_rela }, 528 [R_RISCV_RELATIVE] = { .reloc_handler = dynamic_linking_not_supported }, 529 [R_RISCV_COPY] = { .reloc_handler = dynamic_linking_not_supported }, 530 [R_RISCV_JUMP_SLOT] = { .reloc_handler = dynamic_linking_not_supported }, 531 [R_RISCV_TLS_DTPMOD32] = { .reloc_handler = dynamic_linking_not_supported }, 532 [R_RISCV_TLS_DTPMOD64] = { .reloc_handler = dynamic_linking_not_supported }, 533 [R_RISCV_TLS_DTPREL32] = { .reloc_handler = dynamic_linking_not_supported }, 534 [R_RISCV_TLS_DTPREL64] = { .reloc_handler = dynamic_linking_not_supported }, 535 [R_RISCV_TLS_TPREL32] = { .reloc_handler = dynamic_linking_not_supported }, 536 [R_RISCV_TLS_TPREL64] = { .reloc_handler = dynamic_linking_not_supported }, 537 /* 12-15 undefined */ 538 [R_RISCV_BRANCH] = { .reloc_handler = apply_r_riscv_branch_rela }, 539 [R_RISCV_JAL] = { .reloc_handler = apply_r_riscv_jal_rela }, 540 [R_RISCV_CALL] = { .reloc_handler = apply_r_riscv_call_rela }, 541 [R_RISCV_CALL_PLT] = { .reloc_handler = apply_r_riscv_call_plt_rela }, 542 [R_RISCV_GOT_HI20] = { .reloc_handler = apply_r_riscv_got_hi20_rela }, 543 [R_RISCV_TLS_GOT_HI20] = { .reloc_handler = tls_not_supported }, 544 [R_RISCV_TLS_GD_HI20] = { .reloc_handler = tls_not_supported }, 545 [R_RISCV_PCREL_HI20] = { .reloc_handler = apply_r_riscv_pcrel_hi20_rela }, 546 [R_RISCV_PCREL_LO12_I] = { .reloc_handler = apply_r_riscv_pcrel_lo12_i_rela }, 547 [R_RISCV_PCREL_LO12_S] = { .reloc_handler = apply_r_riscv_pcrel_lo12_s_rela }, 548 [R_RISCV_HI20] = { .reloc_handler = apply_r_riscv_hi20_rela }, 549 [R_RISCV_LO12_I] = { .reloc_handler = apply_r_riscv_lo12_i_rela }, 550 [R_RISCV_LO12_S] = { .reloc_handler = apply_r_riscv_lo12_s_rela }, 551 [R_RISCV_TPREL_HI20] = { .reloc_handler = tls_not_supported }, 552 [R_RISCV_TPREL_LO12_I] = { .reloc_handler = tls_not_supported }, 553 [R_RISCV_TPREL_LO12_S] = { .reloc_handler = tls_not_supported }, 554 [R_RISCV_TPREL_ADD] = { .reloc_handler = tls_not_supported }, 555 [R_RISCV_ADD8] = { .reloc_handler = apply_r_riscv_add8_rela, 556 .accumulate_handler = apply_8_bit_accumulation }, 557 [R_RISCV_ADD16] = { .reloc_handler = apply_r_riscv_add16_rela, 558 .accumulate_handler = apply_16_bit_accumulation }, 559 [R_RISCV_ADD32] = { .reloc_handler = apply_r_riscv_add32_rela, 560 .accumulate_handler = apply_32_bit_accumulation }, 561 [R_RISCV_ADD64] = { .reloc_handler = apply_r_riscv_add64_rela, 562 .accumulate_handler = apply_64_bit_accumulation }, 563 [R_RISCV_SUB8] = { .reloc_handler = apply_r_riscv_sub8_rela, 564 .accumulate_handler = apply_8_bit_accumulation }, 565 [R_RISCV_SUB16] = { .reloc_handler = apply_r_riscv_sub16_rela, 566 .accumulate_handler = apply_16_bit_accumulation }, 567 [R_RISCV_SUB32] = { .reloc_handler = apply_r_riscv_sub32_rela, 568 .accumulate_handler = apply_32_bit_accumulation }, 569 [R_RISCV_SUB64] = { .reloc_handler = apply_r_riscv_sub64_rela, 570 .accumulate_handler = apply_64_bit_accumulation }, 571 /* 41-42 reserved for future standard use */ 572 [R_RISCV_ALIGN] = { .reloc_handler = apply_r_riscv_align_rela }, 573 [R_RISCV_RVC_BRANCH] = { .reloc_handler = apply_r_riscv_rvc_branch_rela }, 574 [R_RISCV_RVC_JUMP] = { .reloc_handler = apply_r_riscv_rvc_jump_rela }, 575 /* 46-50 reserved for future standard use */ 576 [R_RISCV_RELAX] = { .reloc_handler = apply_r_riscv_relax_rela }, 577 [R_RISCV_SUB6] = { .reloc_handler = apply_r_riscv_sub6_rela, 578 .accumulate_handler = apply_6_bit_accumulation }, 579 [R_RISCV_SET6] = { .reloc_handler = apply_r_riscv_set6_rela, 580 .accumulate_handler = apply_6_bit_accumulation }, 581 [R_RISCV_SET8] = { .reloc_handler = apply_r_riscv_set8_rela, 582 .accumulate_handler = apply_8_bit_accumulation }, 583 [R_RISCV_SET16] = { .reloc_handler = apply_r_riscv_set16_rela, 584 .accumulate_handler = apply_16_bit_accumulation }, 585 [R_RISCV_SET32] = { .reloc_handler = apply_r_riscv_set32_rela, 586 .accumulate_handler = apply_32_bit_accumulation }, 587 [R_RISCV_32_PCREL] = { .reloc_handler = apply_r_riscv_32_pcrel_rela }, 588 [R_RISCV_IRELATIVE] = { .reloc_handler = dynamic_linking_not_supported }, 589 [R_RISCV_PLT32] = { .reloc_handler = apply_r_riscv_plt32_rela }, 590 [R_RISCV_SET_ULEB128] = { .reloc_handler = apply_r_riscv_set_uleb128, 591 .accumulate_handler = apply_uleb128_accumulation }, 592 [R_RISCV_SUB_ULEB128] = { .reloc_handler = apply_r_riscv_sub_uleb128, 593 .accumulate_handler = apply_uleb128_accumulation }, 594 /* 62-191 reserved for future standard use */ 595 /* 192-255 nonstandard ABI extensions */ 596 }; 597 598 static void 599 process_accumulated_relocations(struct module *me, 600 struct hlist_head **relocation_hashtable, 601 struct list_head *used_buckets_list) 602 { 603 /* 604 * Only ADD/SUB/SET/ULEB128 should end up here. 605 * 606 * Each bucket may have more than one relocation location. All 607 * relocations for a location are stored in a list in a bucket. 608 * 609 * Relocations are applied to a temp variable before being stored to the 610 * provided location to check for overflow. This also allows ULEB128 to 611 * properly decide how many entries are needed before storing to 612 * location. The final value is stored into location using the handler 613 * for the last relocation to an address. 614 * 615 * Three layers of indexing: 616 * - Each of the buckets in use 617 * - Groups of relocations in each bucket by location address 618 * - Each relocation entry for a location address 619 */ 620 struct used_bucket *bucket_iter; 621 struct used_bucket *bucket_iter_tmp; 622 struct relocation_head *rel_head_iter; 623 struct hlist_node *rel_head_iter_tmp; 624 struct relocation_entry *rel_entry_iter; 625 struct relocation_entry *rel_entry_iter_tmp; 626 int curr_type; 627 void *location; 628 long buffer; 629 630 list_for_each_entry_safe(bucket_iter, bucket_iter_tmp, 631 used_buckets_list, head) { 632 hlist_for_each_entry_safe(rel_head_iter, rel_head_iter_tmp, 633 bucket_iter->bucket, node) { 634 buffer = 0; 635 location = rel_head_iter->location; 636 list_for_each_entry_safe(rel_entry_iter, 637 rel_entry_iter_tmp, 638 rel_head_iter->rel_entry, 639 head) { 640 curr_type = rel_entry_iter->type; 641 reloc_handlers[curr_type].reloc_handler( 642 me, &buffer, rel_entry_iter->value); 643 kfree(rel_entry_iter); 644 } 645 reloc_handlers[curr_type].accumulate_handler( 646 me, location, buffer); 647 kfree(rel_head_iter); 648 } 649 kfree(bucket_iter); 650 } 651 652 kfree(*relocation_hashtable); 653 } 654 655 static int add_relocation_to_accumulate(struct module *me, int type, 656 void *location, 657 unsigned int hashtable_bits, Elf_Addr v, 658 struct hlist_head *relocation_hashtable, 659 struct list_head *used_buckets_list) 660 { 661 struct relocation_entry *entry; 662 struct relocation_head *rel_head; 663 struct hlist_head *current_head; 664 struct used_bucket *bucket; 665 unsigned long hash; 666 667 entry = kmalloc(sizeof(*entry), GFP_KERNEL); 668 669 if (!entry) 670 return -ENOMEM; 671 672 INIT_LIST_HEAD(&entry->head); 673 entry->type = type; 674 entry->value = v; 675 676 hash = hash_min((uintptr_t)location, hashtable_bits); 677 678 current_head = &relocation_hashtable[hash]; 679 680 /* 681 * Search for the relocation_head for the relocations that happen at the 682 * provided location 683 */ 684 bool found = false; 685 struct relocation_head *rel_head_iter; 686 687 hlist_for_each_entry(rel_head_iter, current_head, node) { 688 if (rel_head_iter->location == location) { 689 found = true; 690 rel_head = rel_head_iter; 691 break; 692 } 693 } 694 695 /* 696 * If there has not yet been any relocations at the provided location, 697 * create a relocation_head for that location and populate it with this 698 * relocation_entry. 699 */ 700 if (!found) { 701 rel_head = kmalloc(sizeof(*rel_head), GFP_KERNEL); 702 703 if (!rel_head) { 704 kfree(entry); 705 return -ENOMEM; 706 } 707 708 rel_head->rel_entry = 709 kmalloc(sizeof(struct list_head), GFP_KERNEL); 710 711 if (!rel_head->rel_entry) { 712 kfree(entry); 713 kfree(rel_head); 714 return -ENOMEM; 715 } 716 717 INIT_LIST_HEAD(rel_head->rel_entry); 718 rel_head->location = location; 719 INIT_HLIST_NODE(&rel_head->node); 720 if (!current_head->first) { 721 bucket = 722 kmalloc(sizeof(struct used_bucket), GFP_KERNEL); 723 724 if (!bucket) { 725 kfree(entry); 726 kfree(rel_head->rel_entry); 727 kfree(rel_head); 728 return -ENOMEM; 729 } 730 731 INIT_LIST_HEAD(&bucket->head); 732 bucket->bucket = current_head; 733 list_add(&bucket->head, used_buckets_list); 734 } 735 hlist_add_head(&rel_head->node, current_head); 736 } 737 738 /* Add relocation to head of discovered rel_head */ 739 list_add_tail(&entry->head, rel_head->rel_entry); 740 741 return 0; 742 } 743 744 static unsigned int 745 initialize_relocation_hashtable(unsigned int num_relocations, 746 struct hlist_head **relocation_hashtable) 747 { 748 /* Can safely assume that bits is not greater than sizeof(long) */ 749 unsigned long hashtable_size = roundup_pow_of_two(num_relocations); 750 /* 751 * When hashtable_size == 1, hashtable_bits == 0. 752 * This is valid because the hashing algorithm returns 0 in this case. 753 */ 754 unsigned int hashtable_bits = ilog2(hashtable_size); 755 756 /* 757 * Double size of hashtable if num_relocations * 1.25 is greater than 758 * hashtable_size. 759 */ 760 int should_double_size = ((num_relocations + (num_relocations >> 2)) > (hashtable_size)); 761 762 hashtable_bits += should_double_size; 763 764 hashtable_size <<= should_double_size; 765 766 *relocation_hashtable = kmalloc_array(hashtable_size, 767 sizeof(**relocation_hashtable), 768 GFP_KERNEL); 769 if (!*relocation_hashtable) 770 return 0; 771 772 __hash_init(*relocation_hashtable, hashtable_size); 773 774 return hashtable_bits; 775 } 776 777 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 778 unsigned int symindex, unsigned int relsec, 779 struct module *me) 780 { 781 Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr; 782 int (*handler)(struct module *me, void *location, Elf_Addr v); 783 Elf_Sym *sym; 784 void *location; 785 unsigned int i, type; 786 unsigned int j_idx = 0; 787 Elf_Addr v; 788 int res; 789 unsigned int num_relocations = sechdrs[relsec].sh_size / sizeof(*rel); 790 struct hlist_head *relocation_hashtable; 791 struct list_head used_buckets_list; 792 unsigned int hashtable_bits; 793 794 hashtable_bits = initialize_relocation_hashtable(num_relocations, 795 &relocation_hashtable); 796 797 if (!relocation_hashtable) 798 return -ENOMEM; 799 800 INIT_LIST_HEAD(&used_buckets_list); 801 802 pr_debug("Applying relocate section %u to %u\n", relsec, 803 sechdrs[relsec].sh_info); 804 805 for (i = 0; i < num_relocations; i++) { 806 /* This is where to make the change */ 807 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 808 + rel[i].r_offset; 809 /* This is the symbol it is referring to */ 810 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 811 + ELF_RISCV_R_SYM(rel[i].r_info); 812 if (IS_ERR_VALUE(sym->st_value)) { 813 /* Ignore unresolved weak symbol */ 814 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 815 continue; 816 pr_warn("%s: Unknown symbol %s\n", 817 me->name, strtab + sym->st_name); 818 return -ENOENT; 819 } 820 821 type = ELF_RISCV_R_TYPE(rel[i].r_info); 822 823 if (type < ARRAY_SIZE(reloc_handlers)) 824 handler = reloc_handlers[type].reloc_handler; 825 else 826 handler = NULL; 827 828 if (!handler) { 829 pr_err("%s: Unknown relocation type %u\n", 830 me->name, type); 831 return -EINVAL; 832 } 833 834 v = sym->st_value + rel[i].r_addend; 835 836 if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) { 837 unsigned int j = j_idx; 838 bool found = false; 839 840 do { 841 unsigned long hi20_loc = 842 sechdrs[sechdrs[relsec].sh_info].sh_addr 843 + rel[j].r_offset; 844 u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info); 845 846 /* Find the corresponding HI20 relocation entry */ 847 if (hi20_loc == sym->st_value 848 && (hi20_type == R_RISCV_PCREL_HI20 849 || hi20_type == R_RISCV_GOT_HI20)) { 850 s32 hi20, lo12; 851 Elf_Sym *hi20_sym = 852 (Elf_Sym *)sechdrs[symindex].sh_addr 853 + ELF_RISCV_R_SYM(rel[j].r_info); 854 unsigned long hi20_sym_val = 855 hi20_sym->st_value 856 + rel[j].r_addend; 857 858 /* Calculate lo12 */ 859 size_t offset = hi20_sym_val - hi20_loc; 860 if (IS_ENABLED(CONFIG_MODULE_SECTIONS) 861 && hi20_type == R_RISCV_GOT_HI20) { 862 offset = module_emit_got_entry( 863 me, hi20_sym_val); 864 offset = offset - hi20_loc; 865 } 866 hi20 = (offset + 0x800) & 0xfffff000; 867 lo12 = offset - hi20; 868 v = lo12; 869 found = true; 870 871 break; 872 } 873 874 j++; 875 if (j > sechdrs[relsec].sh_size / sizeof(*rel)) 876 j = 0; 877 878 } while (j_idx != j); 879 880 if (!found) { 881 pr_err( 882 "%s: Can not find HI20 relocation information\n", 883 me->name); 884 return -EINVAL; 885 } 886 887 /* Record the previous j-loop end index */ 888 j_idx = j; 889 } 890 891 if (reloc_handlers[type].accumulate_handler) 892 res = add_relocation_to_accumulate(me, type, location, 893 hashtable_bits, v, 894 relocation_hashtable, 895 &used_buckets_list); 896 else 897 res = handler(me, location, v); 898 if (res) 899 return res; 900 } 901 902 process_accumulated_relocations(me, &relocation_hashtable, 903 &used_buckets_list); 904 905 return 0; 906 } 907 908 #if defined(CONFIG_MMU) && defined(CONFIG_64BIT) 909 void *module_alloc(unsigned long size) 910 { 911 return __vmalloc_node_range(size, 1, MODULES_VADDR, 912 MODULES_END, GFP_KERNEL, 913 PAGE_KERNEL, VM_FLUSH_RESET_PERMS, 914 NUMA_NO_NODE, 915 __builtin_return_address(0)); 916 } 917 #endif 918 919 int module_finalize(const Elf_Ehdr *hdr, 920 const Elf_Shdr *sechdrs, 921 struct module *me) 922 { 923 const Elf_Shdr *s; 924 925 s = find_section(hdr, sechdrs, ".alternative"); 926 if (s) 927 apply_module_alternatives((void *)s->sh_addr, s->sh_size); 928 929 return 0; 930 } 931