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/module.h> 32 #include <linux/spinlock.h> 33 #include <linux/jump_label.h> 34 35 #include <asm/pgtable.h> /* MODULE_START */ 36 37 struct mips_hi16 { 38 struct mips_hi16 *next; 39 Elf_Addr *addr; 40 Elf_Addr value; 41 }; 42 43 static struct mips_hi16 *mips_hi16_list; 44 45 static LIST_HEAD(dbe_list); 46 static DEFINE_SPINLOCK(dbe_lock); 47 48 void *module_alloc(unsigned long size) 49 { 50 #ifdef MODULE_START 51 return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END, 52 GFP_KERNEL, PAGE_KERNEL, -1, 53 __builtin_return_address(0)); 54 #else 55 if (size == 0) 56 return NULL; 57 return vmalloc(size); 58 #endif 59 } 60 61 /* Free memory returned from module_alloc */ 62 void module_free(struct module *mod, void *module_region) 63 { 64 vfree(module_region); 65 } 66 67 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 68 char *secstrings, struct module *mod) 69 { 70 return 0; 71 } 72 73 static int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v) 74 { 75 return 0; 76 } 77 78 static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v) 79 { 80 *location += v; 81 82 return 0; 83 } 84 85 static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v) 86 { 87 *location = v; 88 89 return 0; 90 } 91 92 static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v) 93 { 94 if (v % 4) { 95 pr_err("module %s: dangerous R_MIPS_26 REL relocation\n", 96 me->name); 97 return -ENOEXEC; 98 } 99 100 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 101 printk(KERN_ERR 102 "module %s: relocation overflow\n", 103 me->name); 104 return -ENOEXEC; 105 } 106 107 *location = (*location & ~0x03ffffff) | 108 ((*location + (v >> 2)) & 0x03ffffff); 109 110 return 0; 111 } 112 113 static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v) 114 { 115 if (v % 4) { 116 pr_err("module %s: dangerous R_MIPS_26 RELArelocation\n", 117 me->name); 118 return -ENOEXEC; 119 } 120 121 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 122 printk(KERN_ERR 123 "module %s: relocation overflow\n", 124 me->name); 125 return -ENOEXEC; 126 } 127 128 *location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff); 129 130 return 0; 131 } 132 133 static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v) 134 { 135 struct mips_hi16 *n; 136 137 /* 138 * We cannot relocate this one now because we don't know the value of 139 * the carry we need to add. Save the information, and let LO16 do the 140 * actual relocation. 141 */ 142 n = kmalloc(sizeof *n, GFP_KERNEL); 143 if (!n) 144 return -ENOMEM; 145 146 n->addr = (Elf_Addr *)location; 147 n->value = v; 148 n->next = mips_hi16_list; 149 mips_hi16_list = n; 150 151 return 0; 152 } 153 154 static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v) 155 { 156 *location = (*location & 0xffff0000) | 157 ((((long long) v + 0x8000LL) >> 16) & 0xffff); 158 159 return 0; 160 } 161 162 static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v) 163 { 164 unsigned long insnlo = *location; 165 Elf_Addr val, vallo; 166 167 /* Sign extend the addend we extract from the lo insn. */ 168 vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000; 169 170 if (mips_hi16_list != NULL) { 171 struct mips_hi16 *l; 172 173 l = mips_hi16_list; 174 while (l != NULL) { 175 struct mips_hi16 *next; 176 unsigned long insn; 177 178 /* 179 * The value for the HI16 had best be the same. 180 */ 181 if (v != l->value) 182 goto out_danger; 183 184 /* 185 * Do the HI16 relocation. Note that we actually don't 186 * need to know anything about the LO16 itself, except 187 * where to find the low 16 bits of the addend needed 188 * by the LO16. 189 */ 190 insn = *l->addr; 191 val = ((insn & 0xffff) << 16) + vallo; 192 val += v; 193 194 /* 195 * Account for the sign extension that will happen in 196 * the low bits. 197 */ 198 val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff; 199 200 insn = (insn & ~0xffff) | val; 201 *l->addr = insn; 202 203 next = l->next; 204 kfree(l); 205 l = next; 206 } 207 208 mips_hi16_list = NULL; 209 } 210 211 /* 212 * Ok, we're done with the HI16 relocs. Now deal with the LO16. 213 */ 214 val = v + vallo; 215 insnlo = (insnlo & ~0xffff) | (val & 0xffff); 216 *location = insnlo; 217 218 return 0; 219 220 out_danger: 221 pr_err("module %s: dangerous R_MIPS_LO16 REL relocation\n", me->name); 222 223 return -ENOEXEC; 224 } 225 226 static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v) 227 { 228 *location = (*location & 0xffff0000) | (v & 0xffff); 229 230 return 0; 231 } 232 233 static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v) 234 { 235 *(Elf_Addr *)location = v; 236 237 return 0; 238 } 239 240 static int apply_r_mips_higher_rela(struct module *me, u32 *location, 241 Elf_Addr v) 242 { 243 *location = (*location & 0xffff0000) | 244 ((((long long) v + 0x80008000LL) >> 32) & 0xffff); 245 246 return 0; 247 } 248 249 static int apply_r_mips_highest_rela(struct module *me, u32 *location, 250 Elf_Addr v) 251 { 252 *location = (*location & 0xffff0000) | 253 ((((long long) v + 0x800080008000LL) >> 48) & 0xffff); 254 255 return 0; 256 } 257 258 static int (*reloc_handlers_rel[]) (struct module *me, u32 *location, 259 Elf_Addr v) = { 260 [R_MIPS_NONE] = apply_r_mips_none, 261 [R_MIPS_32] = apply_r_mips_32_rel, 262 [R_MIPS_26] = apply_r_mips_26_rel, 263 [R_MIPS_HI16] = apply_r_mips_hi16_rel, 264 [R_MIPS_LO16] = apply_r_mips_lo16_rel 265 }; 266 267 static int (*reloc_handlers_rela[]) (struct module *me, u32 *location, 268 Elf_Addr v) = { 269 [R_MIPS_NONE] = apply_r_mips_none, 270 [R_MIPS_32] = apply_r_mips_32_rela, 271 [R_MIPS_26] = apply_r_mips_26_rela, 272 [R_MIPS_HI16] = apply_r_mips_hi16_rela, 273 [R_MIPS_LO16] = apply_r_mips_lo16_rela, 274 [R_MIPS_64] = apply_r_mips_64_rela, 275 [R_MIPS_HIGHER] = apply_r_mips_higher_rela, 276 [R_MIPS_HIGHEST] = apply_r_mips_highest_rela 277 }; 278 279 int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, 280 unsigned int symindex, unsigned int relsec, 281 struct module *me) 282 { 283 Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr; 284 Elf_Sym *sym; 285 u32 *location; 286 unsigned int i; 287 Elf_Addr v; 288 int res; 289 290 pr_debug("Applying relocate section %u to %u\n", relsec, 291 sechdrs[relsec].sh_info); 292 293 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 294 /* This is where to make the change */ 295 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 296 + rel[i].r_offset; 297 /* This is the symbol it is referring to */ 298 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 299 + ELF_MIPS_R_SYM(rel[i]); 300 if (IS_ERR_VALUE(sym->st_value)) { 301 /* Ignore unresolved weak symbol */ 302 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 303 continue; 304 printk(KERN_WARNING "%s: Unknown symbol %s\n", 305 me->name, strtab + sym->st_name); 306 return -ENOENT; 307 } 308 309 v = sym->st_value; 310 311 res = reloc_handlers_rel[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 312 if (res) 313 return res; 314 } 315 316 return 0; 317 } 318 319 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 320 unsigned int symindex, unsigned int relsec, 321 struct module *me) 322 { 323 Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr; 324 Elf_Sym *sym; 325 u32 *location; 326 unsigned int i; 327 Elf_Addr v; 328 int res; 329 330 pr_debug("Applying relocate section %u to %u\n", relsec, 331 sechdrs[relsec].sh_info); 332 333 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 334 /* This is where to make the change */ 335 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 336 + rel[i].r_offset; 337 /* This is the symbol it is referring to */ 338 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 339 + ELF_MIPS_R_SYM(rel[i]); 340 if (IS_ERR_VALUE(sym->st_value)) { 341 /* Ignore unresolved weak symbol */ 342 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 343 continue; 344 printk(KERN_WARNING "%s: Unknown symbol %s\n", 345 me->name, strtab + sym->st_name); 346 return -ENOENT; 347 } 348 349 v = sym->st_value + rel[i].r_addend; 350 351 res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 352 if (res) 353 return res; 354 } 355 356 return 0; 357 } 358 359 /* Given an address, look for it in the module exception tables. */ 360 const struct exception_table_entry *search_module_dbetables(unsigned long addr) 361 { 362 unsigned long flags; 363 const struct exception_table_entry *e = NULL; 364 struct mod_arch_specific *dbe; 365 366 spin_lock_irqsave(&dbe_lock, flags); 367 list_for_each_entry(dbe, &dbe_list, dbe_list) { 368 e = search_extable(dbe->dbe_start, dbe->dbe_end - 1, addr); 369 if (e) 370 break; 371 } 372 spin_unlock_irqrestore(&dbe_lock, flags); 373 374 /* Now, if we found one, we are running inside it now, hence 375 we cannot unload the module, hence no refcnt needed. */ 376 return e; 377 } 378 379 /* Put in dbe list if necessary. */ 380 int module_finalize(const Elf_Ehdr *hdr, 381 const Elf_Shdr *sechdrs, 382 struct module *me) 383 { 384 const Elf_Shdr *s; 385 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 386 387 /* Make jump label nops. */ 388 jump_label_apply_nops(me); 389 390 INIT_LIST_HEAD(&me->arch.dbe_list); 391 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { 392 if (strcmp("__dbe_table", secstrings + s->sh_name) != 0) 393 continue; 394 me->arch.dbe_start = (void *)s->sh_addr; 395 me->arch.dbe_end = (void *)s->sh_addr + s->sh_size; 396 spin_lock_irq(&dbe_lock); 397 list_add(&me->arch.dbe_list, &dbe_list); 398 spin_unlock_irq(&dbe_lock); 399 } 400 return 0; 401 } 402 403 void module_arch_cleanup(struct module *mod) 404 { 405 spin_lock_irq(&dbe_lock); 406 list_del(&mod->arch.dbe_list); 407 spin_unlock_irq(&dbe_lock); 408 } 409