arch/riscv/kernel/module.c

   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         Elf_Addr v;
 787         int res;
 788         unsigned int num_relocations = sechdrs[relsec].sh_size / sizeof(*rel);
 789         struct hlist_head *relocation_hashtable;
 790         struct list_head used_buckets_list;
 791         unsigned int hashtable_bits;
 792
 793         hashtable_bits = initialize_relocation_hashtable(num_relocations,
 794                                                          &relocation_hashtable);
 795
 796         if (!relocation_hashtable)
 797                 return -ENOMEM;
 798
 799         INIT_LIST_HEAD(&used_buckets_list);
 800
 801         pr_debug("Applying relocate section %u to %u\n", relsec,
 802                sechdrs[relsec].sh_info);
 803
 804         for (i = 0; i < num_relocations; i++) {
 805                 /* This is where to make the change */
 806                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 807                         + rel[i].r_offset;
 808                 /* This is the symbol it is referring to */
 809                 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
 810                         + ELF_RISCV_R_SYM(rel[i].r_info);
 811                 if (IS_ERR_VALUE(sym->st_value)) {
 812                         /* Ignore unresolved weak symbol */
 813                         if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
 814                                 continue;
 815                         pr_warn("%s: Unknown symbol %s\n",
 816                                 me->name, strtab + sym->st_name);
 817                         return -ENOENT;
 818                 }
 819
 820                 type = ELF_RISCV_R_TYPE(rel[i].r_info);
 821
 822                 if (type < ARRAY_SIZE(reloc_handlers))
 823                         handler = reloc_handlers[type].reloc_handler;
 824                 else
 825                         handler = NULL;
 826
 827                 if (!handler) {
 828                         pr_err("%s: Unknown relocation type %u\n",
 829                                me->name, type);
 830                         return -EINVAL;
 831                 }
 832
 833                 v = sym->st_value + rel[i].r_addend;
 834
 835                 if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) {
 836                         unsigned int j;
 837
 838                         for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) {
 839                                 unsigned long hi20_loc =
 840                                         sechdrs[sechdrs[relsec].sh_info].sh_addr
 841                                         + rel[j].r_offset;
 842                                 u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info);
 843
 844                                 /* Find the corresponding HI20 relocation entry */
 845                                 if (hi20_loc == sym->st_value
 846                                     && (hi20_type == R_RISCV_PCREL_HI20
 847                                         || hi20_type == R_RISCV_GOT_HI20)) {
 848                                         s32 hi20, lo12;
 849                                         Elf_Sym *hi20_sym =
 850                                                 (Elf_Sym *)sechdrs[symindex].sh_addr
 851                                                 + ELF_RISCV_R_SYM(rel[j].r_info);
 852                                         unsigned long hi20_sym_val =
 853                                                 hi20_sym->st_value
 854                                                 + rel[j].r_addend;
 855
 856                                         /* Calculate lo12 */
 857                                         size_t offset = hi20_sym_val - hi20_loc;
 858                                         if (IS_ENABLED(CONFIG_MODULE_SECTIONS)
 859                                             && hi20_type == R_RISCV_GOT_HI20) {
 860                                                 offset = module_emit_got_entry(
 861                                                          me, hi20_sym_val);
 862                                                 offset = offset - hi20_loc;
 863                                         }
 864                                         hi20 = (offset + 0x800) & 0xfffff000;
 865                                         lo12 = offset - hi20;
 866                                         v = lo12;
 867
 868                                         break;
 869                                 }
 870                         }
 871                         if (j == sechdrs[relsec].sh_size / sizeof(*rel)) {
 872                                 pr_err(
 873                                   "%s: Can not find HI20 relocation information\n",
 874                                   me->name);
 875                                 return -EINVAL;
 876                         }
 877                 }
 878
 879                 if (reloc_handlers[type].accumulate_handler)
 880                         res = add_relocation_to_accumulate(me, type, location,
 881                                                            hashtable_bits, v,
 882                                                            relocation_hashtable,
 883                                                            &used_buckets_list);
 884                 else
 885                         res = handler(me, location, v);
 886                 if (res)
 887                         return res;
 888         }
 889
 890         process_accumulated_relocations(me, &relocation_hashtable,
 891                                         &used_buckets_list);
 892
 893         return 0;
 894 }
 895
 896 #if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
 897 void *module_alloc(unsigned long size)
 898 {
 899         return __vmalloc_node_range(size, 1, MODULES_VADDR,
 900                                     MODULES_END, GFP_KERNEL,
 901                                     PAGE_KERNEL, VM_FLUSH_RESET_PERMS,
 902                                     NUMA_NO_NODE,
 903                                     __builtin_return_address(0));
 904 }
 905 #endif
 906
 907 int module_finalize(const Elf_Ehdr *hdr,
 908                     const Elf_Shdr *sechdrs,
 909                     struct module *me)
 910 {
 911         const Elf_Shdr *s;
 912
 913         s = find_section(hdr, sechdrs, ".alternative");
 914         if (s)
 915                 apply_module_alternatives((void *)s->sh_addr, s->sh_size);
 916
 917         return 0;
 918 }