1 // SPDX-License-Identifier: GPL-2.0-only !! 1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* 2 /*
3 * Copyright (C) 2007-2009 Michal Simek <monst !! 3 *
4 * Copyright (C) 2007-2009 PetaLogix !! 4 * Copyright (C) 2001 Rusty Russell.
>> 5 * Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
>> 6 * Copyright (C) 2005 Thiemo Seufer
5 */ 7 */
6 8
7 #include <linux/export.h> !! 9 #undef DEBUG
>> 10
>> 11 #include <linux/extable.h>
8 #include <linux/moduleloader.h> 12 #include <linux/moduleloader.h>
9 #include <linux/kernel.h> <<
10 #include <linux/elf.h> 13 #include <linux/elf.h>
11 #include <linux/vmalloc.h> !! 14 #include <linux/mm.h>
>> 15 #include <linux/numa.h>
>> 16 #include <linux/slab.h>
12 #include <linux/fs.h> 17 #include <linux/fs.h>
13 #include <linux/string.h> 18 #include <linux/string.h>
14 #include <linux/pgtable.h> !! 19 #include <linux/kernel.h>
>> 20 #include <linux/spinlock.h>
>> 21 #include <linux/jump_label.h>
>> 22 #include <asm/jump_label.h>
>> 23
>> 24 struct mips_hi16 {
>> 25 struct mips_hi16 *next;
>> 26 Elf_Addr *addr;
>> 27 Elf_Addr value;
>> 28 };
15 29
16 #include <asm/cacheflush.h> !! 30 static LIST_HEAD(dbe_list);
>> 31 static DEFINE_SPINLOCK(dbe_lock);
17 32
18 int apply_relocate_add(Elf32_Shdr *sechdrs, co !! 33 static void apply_r_mips_32(u32 *location, u32 base, Elf_Addr v)
19 unsigned int symindex, unsigned int re <<
20 { 34 {
>> 35 *location = base + v;
>> 36 }
21 37
22 unsigned int i; !! 38 static int apply_r_mips_26(struct module *me, u32 *location, u32 base,
23 Elf32_Rela *rela = (void *)sechdrs[rel !! 39 Elf_Addr v)
24 Elf32_Sym *sym; !! 40 {
25 unsigned long int *location; !! 41 if (v % 4) {
26 unsigned long int value; !! 42 pr_err("module %s: dangerous R_MIPS_26 relocation\n",
>> 43 me->name);
>> 44 return -ENOEXEC;
>> 45 }
27 46
28 pr_debug("Applying add relocation sect !! 47 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
29 relsec, sechdrs[relsec].sh_inf !! 48 pr_err("module %s: relocation overflow\n",
>> 49 me->name);
>> 50 return -ENOEXEC;
>> 51 }
30 52
31 for (i = 0; i < sechdrs[relsec].sh_siz !! 53 *location = (*location & ~0x03ffffff) |
>> 54 ((base + (v >> 2)) & 0x03ffffff);
32 55
33 location = (void *)sechdrs[sec !! 56 return 0;
34 rela[i].r_offs !! 57 }
35 sym = (Elf32_Sym *)sechdrs[sym <<
36 ELF32_R_SYM(rela[i].r_ <<
37 value = sym->st_value + rela[i <<
38 58
39 switch (ELF32_R_TYPE(rela[i].r !! 59 static int apply_r_mips_hi16(struct module *me, u32 *location, Elf_Addr v,
>> 60 bool rela)
>> 61 {
>> 62 struct mips_hi16 *n;
40 63
41 /* !! 64 if (rela) {
42 * Be careful! mb-gcc / mb-ld !! 65 *location = (*location & 0xffff0000) |
43 * text and the reloc table. I !! 66 ((((long long) v + 0x8000LL) >> 16) & 0xffff);
44 * read the current contents o !! 67 return 0;
45 * then store the result back !! 68 }
46 */ <<
47 69
48 case R_MICROBLAZE_32: !! 70 /*
49 *location = value; !! 71 * We cannot relocate this one now because we don't know the value of
50 break; !! 72 * the carry we need to add. Save the information, and let LO16 do the
>> 73 * actual relocation.
>> 74 */
>> 75 n = kmalloc(sizeof *n, GFP_KERNEL);
>> 76 if (!n)
>> 77 return -ENOMEM;
>> 78
>> 79 n->addr = (Elf_Addr *)location;
>> 80 n->value = v;
>> 81 n->next = me->arch.r_mips_hi16_list;
>> 82 me->arch.r_mips_hi16_list = n;
51 83
52 case R_MICROBLAZE_64: !! 84 return 0;
53 location[0] = (locatio !! 85 }
54 (value <<
55 location[1] = (locatio <<
56 (value <<
57 break; <<
58 86
59 case R_MICROBLAZE_64_PCREL: !! 87 static void free_relocation_chain(struct mips_hi16 *l)
60 value -= (unsigned lon !! 88 {
61 location[0] = (locatio !! 89 struct mips_hi16 *next;
62 (value <<
63 location[1] = (locatio <<
64 (value <<
65 pr_debug("R_MICROBLAZE <<
66 value); <<
67 break; <<
68 90
69 case R_MICROBLAZE_32_PCREL_LO: !! 91 while (l) {
70 pr_debug("R_MICROBLAZE !! 92 next = l->next;
71 break; !! 93 kfree(l);
>> 94 l = next;
>> 95 }
>> 96 }
72 97
73 case R_MICROBLAZE_64_NONE: !! 98 static int apply_r_mips_lo16(struct module *me, u32 *location,
74 pr_debug("R_MICROBLAZE !! 99 u32 base, Elf_Addr v, bool rela)
75 break; !! 100 {
>> 101 unsigned long insnlo = base;
>> 102 struct mips_hi16 *l;
>> 103 Elf_Addr val, vallo;
>> 104
>> 105 if (rela) {
>> 106 *location = (*location & 0xffff0000) | (v & 0xffff);
>> 107 return 0;
>> 108 }
76 109
77 case R_MICROBLAZE_NONE: !! 110 /* Sign extend the addend we extract from the lo insn. */
78 pr_debug("R_MICROBLAZE !! 111 vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
79 break; <<
80 112
81 default: !! 113 if (me->arch.r_mips_hi16_list != NULL) {
82 pr_err("module %s: Unk !! 114 l = me->arch.r_mips_hi16_list;
83 module->name, !! 115 while (l != NULL) {
84 ELF32_R_TYPE(r !! 116 struct mips_hi16 *next;
85 return -ENOEXEC; !! 117 unsigned long insn;
>> 118
>> 119 /*
>> 120 * The value for the HI16 had best be the same.
>> 121 */
>> 122 if (v != l->value)
>> 123 goto out_danger;
>> 124
>> 125 /*
>> 126 * Do the HI16 relocation. Note that we actually don't
>> 127 * need to know anything about the LO16 itself, except
>> 128 * where to find the low 16 bits of the addend needed
>> 129 * by the LO16.
>> 130 */
>> 131 insn = *l->addr;
>> 132 val = ((insn & 0xffff) << 16) + vallo;
>> 133 val += v;
>> 134
>> 135 /*
>> 136 * Account for the sign extension that will happen in
>> 137 * the low bits.
>> 138 */
>> 139 val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
>> 140
>> 141 insn = (insn & ~0xffff) | val;
>> 142 *l->addr = insn;
>> 143
>> 144 next = l->next;
>> 145 kfree(l);
>> 146 l = next;
86 } 147 }
>> 148
>> 149 me->arch.r_mips_hi16_list = NULL;
>> 150 }
>> 151
>> 152 /*
>> 153 * Ok, we're done with the HI16 relocs. Now deal with the LO16.
>> 154 */
>> 155 val = v + vallo;
>> 156 insnlo = (insnlo & ~0xffff) | (val & 0xffff);
>> 157 *location = insnlo;
>> 158
>> 159 return 0;
>> 160
>> 161 out_danger:
>> 162 free_relocation_chain(l);
>> 163 me->arch.r_mips_hi16_list = NULL;
>> 164
>> 165 pr_err("module %s: dangerous R_MIPS_LO16 relocation\n", me->name);
>> 166
>> 167 return -ENOEXEC;
>> 168 }
>> 169
>> 170 static int apply_r_mips_pc(struct module *me, u32 *location, u32 base,
>> 171 Elf_Addr v, unsigned int bits)
>> 172 {
>> 173 unsigned long mask = GENMASK(bits - 1, 0);
>> 174 unsigned long se_bits;
>> 175 long offset;
>> 176
>> 177 if (v % 4) {
>> 178 pr_err("module %s: dangerous R_MIPS_PC%u relocation\n",
>> 179 me->name, bits);
>> 180 return -ENOEXEC;
>> 181 }
>> 182
>> 183 /* retrieve & sign extend implicit addend if any */
>> 184 offset = base & mask;
>> 185 offset |= (offset & BIT(bits - 1)) ? ~mask : 0;
>> 186
>> 187 offset += ((long)v - (long)location) >> 2;
>> 188
>> 189 /* check the sign bit onwards are identical - ie. we didn't overflow */
>> 190 se_bits = (offset & BIT(bits - 1)) ? ~0ul : 0;
>> 191 if ((offset & ~mask) != (se_bits & ~mask)) {
>> 192 pr_err("module %s: relocation overflow\n", me->name);
>> 193 return -ENOEXEC;
87 } 194 }
>> 195
>> 196 *location = (*location & ~mask) | (offset & mask);
>> 197
88 return 0; 198 return 0;
89 } 199 }
90 200
91 int module_finalize(const Elf32_Ehdr *hdr, con !! 201 static int apply_r_mips_pc16(struct module *me, u32 *location, u32 base,
92 struct module *module) !! 202 Elf_Addr v)
93 { 203 {
94 flush_dcache(); !! 204 return apply_r_mips_pc(me, location, base, v, 16);
>> 205 }
>> 206
>> 207 static int apply_r_mips_pc21(struct module *me, u32 *location, u32 base,
>> 208 Elf_Addr v)
>> 209 {
>> 210 return apply_r_mips_pc(me, location, base, v, 21);
>> 211 }
>> 212
>> 213 static int apply_r_mips_pc26(struct module *me, u32 *location, u32 base,
>> 214 Elf_Addr v)
>> 215 {
>> 216 return apply_r_mips_pc(me, location, base, v, 26);
>> 217 }
>> 218
>> 219 static int apply_r_mips_64(u32 *location, Elf_Addr v, bool rela)
>> 220 {
>> 221 if (WARN_ON(!rela))
>> 222 return -EINVAL;
>> 223
>> 224 *(Elf_Addr *)location = v;
>> 225
95 return 0; 226 return 0;
>> 227 }
>> 228
>> 229 static int apply_r_mips_higher(u32 *location, Elf_Addr v, bool rela)
>> 230 {
>> 231 if (WARN_ON(!rela))
>> 232 return -EINVAL;
>> 233
>> 234 *location = (*location & 0xffff0000) |
>> 235 ((((long long)v + 0x80008000LL) >> 32) & 0xffff);
>> 236
>> 237 return 0;
>> 238 }
>> 239
>> 240 static int apply_r_mips_highest(u32 *location, Elf_Addr v, bool rela)
>> 241 {
>> 242 if (WARN_ON(!rela))
>> 243 return -EINVAL;
>> 244
>> 245 *location = (*location & 0xffff0000) |
>> 246 ((((long long)v + 0x800080008000LL) >> 48) & 0xffff);
>> 247
>> 248 return 0;
>> 249 }
>> 250
>> 251 /**
>> 252 * reloc_handler() - Apply a particular relocation to a module
>> 253 * @type: type of the relocation to apply
>> 254 * @me: the module to apply the reloc to
>> 255 * @location: the address at which the reloc is to be applied
>> 256 * @base: the existing value at location for REL-style; 0 for RELA-style
>> 257 * @v: the value of the reloc, with addend for RELA-style
>> 258 * @rela: indication of is this a RELA (true) or REL (false) relocation
>> 259 *
>> 260 * Each implemented relocation function applies a particular type of
>> 261 * relocation to the module @me. Relocs that may be found in either REL or RELA
>> 262 * variants can be handled by making use of the @base & @v parameters which are
>> 263 * set to values which abstract the difference away from the particular reloc
>> 264 * implementations.
>> 265 *
>> 266 * Return: 0 upon success, else -ERRNO
>> 267 */
>> 268 static int reloc_handler(u32 type, struct module *me, u32 *location, u32 base,
>> 269 Elf_Addr v, bool rela)
>> 270 {
>> 271 switch (type) {
>> 272 case R_MIPS_NONE:
>> 273 break;
>> 274 case R_MIPS_32:
>> 275 apply_r_mips_32(location, base, v);
>> 276 break;
>> 277 case R_MIPS_26:
>> 278 return apply_r_mips_26(me, location, base, v);
>> 279 case R_MIPS_HI16:
>> 280 return apply_r_mips_hi16(me, location, v, rela);
>> 281 case R_MIPS_LO16:
>> 282 return apply_r_mips_lo16(me, location, base, v, rela);
>> 283 case R_MIPS_PC16:
>> 284 return apply_r_mips_pc16(me, location, base, v);
>> 285 case R_MIPS_PC21_S2:
>> 286 return apply_r_mips_pc21(me, location, base, v);
>> 287 case R_MIPS_PC26_S2:
>> 288 return apply_r_mips_pc26(me, location, base, v);
>> 289 case R_MIPS_64:
>> 290 return apply_r_mips_64(location, v, rela);
>> 291 case R_MIPS_HIGHER:
>> 292 return apply_r_mips_higher(location, v, rela);
>> 293 case R_MIPS_HIGHEST:
>> 294 return apply_r_mips_highest(location, v, rela);
>> 295 default:
>> 296 pr_err("%s: Unknown relocation type %u\n", me->name, type);
>> 297 return -EINVAL;
>> 298 }
>> 299
>> 300 return 0;
>> 301 }
>> 302
>> 303 static int __apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
>> 304 unsigned int symindex, unsigned int relsec,
>> 305 struct module *me, bool rela)
>> 306 {
>> 307 union {
>> 308 Elf_Mips_Rel *rel;
>> 309 Elf_Mips_Rela *rela;
>> 310 } r;
>> 311 Elf_Sym *sym;
>> 312 u32 *location, base;
>> 313 unsigned int i, type;
>> 314 Elf_Addr v;
>> 315 int err = 0;
>> 316 size_t reloc_sz;
>> 317
>> 318 pr_debug("Applying relocate section %u to %u\n", relsec,
>> 319 sechdrs[relsec].sh_info);
>> 320
>> 321 r.rel = (void *)sechdrs[relsec].sh_addr;
>> 322 reloc_sz = rela ? sizeof(*r.rela) : sizeof(*r.rel);
>> 323 me->arch.r_mips_hi16_list = NULL;
>> 324 for (i = 0; i < sechdrs[relsec].sh_size / reloc_sz; i++) {
>> 325 /* This is where to make the change */
>> 326 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
>> 327 + r.rel->r_offset;
>> 328 /* This is the symbol it is referring to */
>> 329 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
>> 330 + ELF_MIPS_R_SYM(*r.rel);
>> 331 if (sym->st_value >= -MAX_ERRNO) {
>> 332 /* Ignore unresolved weak symbol */
>> 333 if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
>> 334 continue;
>> 335 pr_warn("%s: Unknown symbol %s\n",
>> 336 me->name, strtab + sym->st_name);
>> 337 err = -ENOENT;
>> 338 goto out;
>> 339 }
>> 340
>> 341 type = ELF_MIPS_R_TYPE(*r.rel);
>> 342
>> 343 if (rela) {
>> 344 v = sym->st_value + r.rela->r_addend;
>> 345 base = 0;
>> 346 r.rela = &r.rela[1];
>> 347 } else {
>> 348 v = sym->st_value;
>> 349 base = *location;
>> 350 r.rel = &r.rel[1];
>> 351 }
>> 352
>> 353 err = reloc_handler(type, me, location, base, v, rela);
>> 354 if (err)
>> 355 goto out;
>> 356 }
>> 357
>> 358 out:
>> 359 /*
>> 360 * Normally the hi16 list should be deallocated at this point. A
>> 361 * malformed binary however could contain a series of R_MIPS_HI16
>> 362 * relocations not followed by a R_MIPS_LO16 relocation, or if we hit
>> 363 * an error processing a reloc we might have gotten here before
>> 364 * reaching the R_MIPS_LO16. In either case, free up the list and
>> 365 * return an error.
>> 366 */
>> 367 if (me->arch.r_mips_hi16_list) {
>> 368 free_relocation_chain(me->arch.r_mips_hi16_list);
>> 369 me->arch.r_mips_hi16_list = NULL;
>> 370 err = err ?: -ENOEXEC;
>> 371 }
>> 372
>> 373 return err;
>> 374 }
>> 375
>> 376 int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
>> 377 unsigned int symindex, unsigned int relsec,
>> 378 struct module *me)
>> 379 {
>> 380 return __apply_relocate(sechdrs, strtab, symindex, relsec, me, false);
>> 381 }
>> 382
>> 383 #ifdef CONFIG_MODULES_USE_ELF_RELA
>> 384 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
>> 385 unsigned int symindex, unsigned int relsec,
>> 386 struct module *me)
>> 387 {
>> 388 return __apply_relocate(sechdrs, strtab, symindex, relsec, me, true);
>> 389 }
>> 390 #endif /* CONFIG_MODULES_USE_ELF_RELA */
>> 391
>> 392 /* Given an address, look for it in the module exception tables. */
>> 393 const struct exception_table_entry *search_module_dbetables(unsigned long addr)
>> 394 {
>> 395 unsigned long flags;
>> 396 const struct exception_table_entry *e = NULL;
>> 397 struct mod_arch_specific *dbe;
>> 398
>> 399 spin_lock_irqsave(&dbe_lock, flags);
>> 400 list_for_each_entry(dbe, &dbe_list, dbe_list) {
>> 401 e = search_extable(dbe->dbe_start,
>> 402 dbe->dbe_end - dbe->dbe_start, addr);
>> 403 if (e)
>> 404 break;
>> 405 }
>> 406 spin_unlock_irqrestore(&dbe_lock, flags);
>> 407
>> 408 /* Now, if we found one, we are running inside it now, hence
>> 409 we cannot unload the module, hence no refcnt needed. */
>> 410 return e;
>> 411 }
>> 412
>> 413 /* Put in dbe list if necessary. */
>> 414 int module_finalize(const Elf_Ehdr *hdr,
>> 415 const Elf_Shdr *sechdrs,
>> 416 struct module *me)
>> 417 {
>> 418 const Elf_Shdr *s;
>> 419 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
>> 420
>> 421 if (IS_ENABLED(CONFIG_JUMP_LABEL))
>> 422 jump_label_apply_nops(me);
>> 423
>> 424 INIT_LIST_HEAD(&me->arch.dbe_list);
>> 425 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
>> 426 if (strcmp("__dbe_table", secstrings + s->sh_name) != 0)
>> 427 continue;
>> 428 me->arch.dbe_start = (void *)s->sh_addr;
>> 429 me->arch.dbe_end = (void *)s->sh_addr + s->sh_size;
>> 430 spin_lock_irq(&dbe_lock);
>> 431 list_add(&me->arch.dbe_list, &dbe_list);
>> 432 spin_unlock_irq(&dbe_lock);
>> 433 }
>> 434 return 0;
>> 435 }
>> 436
>> 437 void module_arch_cleanup(struct module *mod)
>> 438 {
>> 439 spin_lock_irq(&dbe_lock);
>> 440 list_del(&mod->arch.dbe_list);
>> 441 spin_unlock_irq(&dbe_lock);
96 } 442 }
97 443
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