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