1 /* 2 * This program is free software; you can redistribute it and/or modify 3 * it under the terms of the GNU General Public License as published by 4 * the Free Software Foundation; either version 2 of the License, or 5 * (at your option) any later version. 6 * 7 * This program is distributed in the hope that it will be useful, 8 * but WITHOUT ANY WARRANTY; without even the implied warranty of 9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 10 * GNU General Public License for more details. 11 * 12 * You should have received a copy of the GNU General Public License 13 * along with this program; if not, write to the Free Software 14 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 15 * 16 * Copyright (C) 2001 Rusty Russell. 17 * Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org) 18 * Copyright (C) 2005 Thiemo Seufer 19 */ 20 21 #undef DEBUG 22 23 #include <linux/moduleloader.h> 24 #include <linux/elf.h> 25 #include <linux/mm.h> 26 #include <linux/vmalloc.h> 27 #include <linux/slab.h> 28 #include <linux/fs.h> 29 #include <linux/string.h> 30 #include <linux/kernel.h> 31 #include <linux/spinlock.h> 32 #include <linux/jump_label.h> 33 34 #include <asm/pgtable.h> /* MODULE_START */ 35 36 struct mips_hi16 { 37 struct mips_hi16 *next; 38 Elf_Addr *addr; 39 Elf_Addr value; 40 }; 41 42 static LIST_HEAD(dbe_list); 43 static DEFINE_SPINLOCK(dbe_lock); 44 45 #ifdef MODULE_START 46 void *module_alloc(unsigned long size) 47 { 48 return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END, 49 GFP_KERNEL, PAGE_KERNEL, -1, 50 __builtin_return_address(0)); 51 } 52 #endif 53 54 static int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v) 55 { 56 return 0; 57 } 58 59 static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v) 60 { 61 *location += v; 62 63 return 0; 64 } 65 66 static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v) 67 { 68 *location = v; 69 70 return 0; 71 } 72 73 static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v) 74 { 75 if (v % 4) { 76 pr_err("module %s: dangerous R_MIPS_26 REL relocation\n", 77 me->name); 78 return -ENOEXEC; 79 } 80 81 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 82 printk(KERN_ERR 83 "module %s: relocation overflow\n", 84 me->name); 85 return -ENOEXEC; 86 } 87 88 *location = (*location & ~0x03ffffff) | 89 ((*location + (v >> 2)) & 0x03ffffff); 90 91 return 0; 92 } 93 94 static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v) 95 { 96 if (v % 4) { 97 pr_err("module %s: dangerous R_MIPS_26 RELArelocation\n", 98 me->name); 99 return -ENOEXEC; 100 } 101 102 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 103 printk(KERN_ERR 104 "module %s: relocation overflow\n", 105 me->name); 106 return -ENOEXEC; 107 } 108 109 *location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff); 110 111 return 0; 112 } 113 114 static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v) 115 { 116 struct mips_hi16 *n; 117 118 /* 119 * We cannot relocate this one now because we don't know the value of 120 * the carry we need to add. Save the information, and let LO16 do the 121 * actual relocation. 122 */ 123 n = kmalloc(sizeof *n, GFP_KERNEL); 124 if (!n) 125 return -ENOMEM; 126 127 n->addr = (Elf_Addr *)location; 128 n->value = v; 129 n->next = me->arch.r_mips_hi16_list; 130 me->arch.r_mips_hi16_list = n; 131 132 return 0; 133 } 134 135 static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v) 136 { 137 *location = (*location & 0xffff0000) | 138 ((((long long) v + 0x8000LL) >> 16) & 0xffff); 139 140 return 0; 141 } 142 143 static void free_relocation_chain(struct mips_hi16 *l) 144 { 145 struct mips_hi16 *next; 146 147 while (l) { 148 next = l->next; 149 kfree(l); 150 l = next; 151 } 152 } 153 154 static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v) 155 { 156 unsigned long insnlo = *location; 157 struct mips_hi16 *l; 158 Elf_Addr val, vallo; 159 160 /* Sign extend the addend we extract from the lo insn. */ 161 vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000; 162 163 if (me->arch.r_mips_hi16_list != NULL) { 164 l = me->arch.r_mips_hi16_list; 165 while (l != NULL) { 166 struct mips_hi16 *next; 167 unsigned long insn; 168 169 /* 170 * The value for the HI16 had best be the same. 171 */ 172 if (v != l->value) 173 goto out_danger; 174 175 /* 176 * Do the HI16 relocation. Note that we actually don't 177 * need to know anything about the LO16 itself, except 178 * where to find the low 16 bits of the addend needed 179 * by the LO16. 180 */ 181 insn = *l->addr; 182 val = ((insn & 0xffff) << 16) + vallo; 183 val += v; 184 185 /* 186 * Account for the sign extension that will happen in 187 * the low bits. 188 */ 189 val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff; 190 191 insn = (insn & ~0xffff) | val; 192 *l->addr = insn; 193 194 next = l->next; 195 kfree(l); 196 l = next; 197 } 198 199 me->arch.r_mips_hi16_list = NULL; 200 } 201 202 /* 203 * Ok, we're done with the HI16 relocs. Now deal with the LO16. 204 */ 205 val = v + vallo; 206 insnlo = (insnlo & ~0xffff) | (val & 0xffff); 207 *location = insnlo; 208 209 return 0; 210 211 out_danger: 212 free_relocation_chain(l); 213 me->arch.r_mips_hi16_list = NULL; 214 215 pr_err("module %s: dangerous R_MIPS_LO16 REL relocation\n", me->name); 216 217 return -ENOEXEC; 218 } 219 220 static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v) 221 { 222 *location = (*location & 0xffff0000) | (v & 0xffff); 223 224 return 0; 225 } 226 227 static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v) 228 { 229 *(Elf_Addr *)location = v; 230 231 return 0; 232 } 233 234 static int apply_r_mips_higher_rela(struct module *me, u32 *location, 235 Elf_Addr v) 236 { 237 *location = (*location & 0xffff0000) | 238 ((((long long) v + 0x80008000LL) >> 32) & 0xffff); 239 240 return 0; 241 } 242 243 static int apply_r_mips_highest_rela(struct module *me, u32 *location, 244 Elf_Addr v) 245 { 246 *location = (*location & 0xffff0000) | 247 ((((long long) v + 0x800080008000LL) >> 48) & 0xffff); 248 249 return 0; 250 } 251 252 static int (*reloc_handlers_rel[]) (struct module *me, u32 *location, 253 Elf_Addr v) = { 254 [R_MIPS_NONE] = apply_r_mips_none, 255 [R_MIPS_32] = apply_r_mips_32_rel, 256 [R_MIPS_26] = apply_r_mips_26_rel, 257 [R_MIPS_HI16] = apply_r_mips_hi16_rel, 258 [R_MIPS_LO16] = apply_r_mips_lo16_rel 259 }; 260 261 static int (*reloc_handlers_rela[]) (struct module *me, u32 *location, 262 Elf_Addr v) = { 263 [R_MIPS_NONE] = apply_r_mips_none, 264 [R_MIPS_32] = apply_r_mips_32_rela, 265 [R_MIPS_26] = apply_r_mips_26_rela, 266 [R_MIPS_HI16] = apply_r_mips_hi16_rela, 267 [R_MIPS_LO16] = apply_r_mips_lo16_rela, 268 [R_MIPS_64] = apply_r_mips_64_rela, 269 [R_MIPS_HIGHER] = apply_r_mips_higher_rela, 270 [R_MIPS_HIGHEST] = apply_r_mips_highest_rela 271 }; 272 273 int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, 274 unsigned int symindex, unsigned int relsec, 275 struct module *me) 276 { 277 Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr; 278 Elf_Sym *sym; 279 u32 *location; 280 unsigned int i; 281 Elf_Addr v; 282 int res; 283 284 pr_debug("Applying relocate section %u to %u\n", relsec, 285 sechdrs[relsec].sh_info); 286 287 me->arch.r_mips_hi16_list = NULL; 288 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 289 /* This is where to make the change */ 290 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 291 + rel[i].r_offset; 292 /* This is the symbol it is referring to */ 293 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 294 + ELF_MIPS_R_SYM(rel[i]); 295 if (IS_ERR_VALUE(sym->st_value)) { 296 /* Ignore unresolved weak symbol */ 297 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 298 continue; 299 printk(KERN_WARNING "%s: Unknown symbol %s\n", 300 me->name, strtab + sym->st_name); 301 return -ENOENT; 302 } 303 304 v = sym->st_value; 305 306 res = reloc_handlers_rel[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 307 if (res) 308 return res; 309 } 310 311 /* 312 * Normally the hi16 list should be deallocated at this point. A 313 * malformed binary however could contain a series of R_MIPS_HI16 314 * relocations not followed by a R_MIPS_LO16 relocation. In that 315 * case, free up the list and return an error. 316 */ 317 if (me->arch.r_mips_hi16_list) { 318 free_relocation_chain(me->arch.r_mips_hi16_list); 319 me->arch.r_mips_hi16_list = NULL; 320 321 return -ENOEXEC; 322 } 323 324 return 0; 325 } 326 327 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 328 unsigned int symindex, unsigned int relsec, 329 struct module *me) 330 { 331 Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr; 332 Elf_Sym *sym; 333 u32 *location; 334 unsigned int i; 335 Elf_Addr v; 336 int res; 337 338 pr_debug("Applying relocate section %u to %u\n", relsec, 339 sechdrs[relsec].sh_info); 340 341 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 342 /* This is where to make the change */ 343 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 344 + rel[i].r_offset; 345 /* This is the symbol it is referring to */ 346 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 347 + ELF_MIPS_R_SYM(rel[i]); 348 if (IS_ERR_VALUE(sym->st_value)) { 349 /* Ignore unresolved weak symbol */ 350 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 351 continue; 352 printk(KERN_WARNING "%s: Unknown symbol %s\n", 353 me->name, strtab + sym->st_name); 354 return -ENOENT; 355 } 356 357 v = sym->st_value + rel[i].r_addend; 358 359 res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 360 if (res) 361 return res; 362 } 363 364 return 0; 365 } 366 367 /* Given an address, look for it in the module exception tables. */ 368 const struct exception_table_entry *search_module_dbetables(unsigned long addr) 369 { 370 unsigned long flags; 371 const struct exception_table_entry *e = NULL; 372 struct mod_arch_specific *dbe; 373 374 spin_lock_irqsave(&dbe_lock, flags); 375 list_for_each_entry(dbe, &dbe_list, dbe_list) { 376 e = search_extable(dbe->dbe_start, dbe->dbe_end - 1, addr); 377 if (e) 378 break; 379 } 380 spin_unlock_irqrestore(&dbe_lock, flags); 381 382 /* Now, if we found one, we are running inside it now, hence 383 we cannot unload the module, hence no refcnt needed. */ 384 return e; 385 } 386 387 /* Put in dbe list if necessary. */ 388 int module_finalize(const Elf_Ehdr *hdr, 389 const Elf_Shdr *sechdrs, 390 struct module *me) 391 { 392 const Elf_Shdr *s; 393 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 394 395 /* Make jump label nops. */ 396 jump_label_apply_nops(me); 397 398 INIT_LIST_HEAD(&me->arch.dbe_list); 399 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { 400 if (strcmp("__dbe_table", secstrings + s->sh_name) != 0) 401 continue; 402 me->arch.dbe_start = (void *)s->sh_addr; 403 me->arch.dbe_end = (void *)s->sh_addr + s->sh_size; 404 spin_lock_irq(&dbe_lock); 405 list_add(&me->arch.dbe_list, &dbe_list); 406 spin_unlock_irq(&dbe_lock); 407 } 408 return 0; 409 } 410 411 void module_arch_cleanup(struct module *mod) 412 { 413 spin_lock_irq(&dbe_lock); 414 list_del(&mod->arch.dbe_list); 415 spin_unlock_irq(&dbe_lock); 416 } 417