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/vmalloc.h> 26 #include <linux/slab.h> 27 #include <linux/fs.h> 28 #include <linux/string.h> 29 #include <linux/kernel.h> 30 #include <linux/module.h> 31 #include <linux/spinlock.h> 32 #include <asm/pgtable.h> /* MODULE_START */ 33 34 struct mips_hi16 { 35 struct mips_hi16 *next; 36 Elf_Addr *addr; 37 Elf_Addr value; 38 }; 39 40 static struct mips_hi16 *mips_hi16_list; 41 42 static LIST_HEAD(dbe_list); 43 static DEFINE_SPINLOCK(dbe_lock); 44 45 void *module_alloc(unsigned long size) 46 { 47 #ifdef MODULE_START 48 struct vm_struct *area; 49 50 size = PAGE_ALIGN(size); 51 if (!size) 52 return NULL; 53 54 area = __get_vm_area(size, VM_ALLOC, MODULE_START, MODULE_END); 55 if (!area) 56 return NULL; 57 58 return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL); 59 #else 60 if (size == 0) 61 return NULL; 62 return vmalloc(size); 63 #endif 64 } 65 66 /* Free memory returned from module_alloc */ 67 void module_free(struct module *mod, void *module_region) 68 { 69 vfree(module_region); 70 /* FIXME: If module_region == mod->init_region, trim exception 71 table entries. */ 72 } 73 74 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 75 char *secstrings, struct module *mod) 76 { 77 return 0; 78 } 79 80 static int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v) 81 { 82 return 0; 83 } 84 85 static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v) 86 { 87 *location += v; 88 89 return 0; 90 } 91 92 static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v) 93 { 94 *location = v; 95 96 return 0; 97 } 98 99 static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v) 100 { 101 if (v % 4) { 102 printk(KERN_ERR "module %s: dangerous relocation\n", me->name); 103 return -ENOEXEC; 104 } 105 106 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 107 printk(KERN_ERR 108 "module %s: relocation overflow\n", 109 me->name); 110 return -ENOEXEC; 111 } 112 113 *location = (*location & ~0x03ffffff) | 114 ((*location + (v >> 2)) & 0x03ffffff); 115 116 return 0; 117 } 118 119 static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v) 120 { 121 if (v % 4) { 122 printk(KERN_ERR "module %s: dangerous relocation\n", me->name); 123 return -ENOEXEC; 124 } 125 126 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 127 printk(KERN_ERR 128 "module %s: relocation overflow\n", 129 me->name); 130 return -ENOEXEC; 131 } 132 133 *location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff); 134 135 return 0; 136 } 137 138 static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v) 139 { 140 struct mips_hi16 *n; 141 142 /* 143 * We cannot relocate this one now because we don't know the value of 144 * the carry we need to add. Save the information, and let LO16 do the 145 * actual relocation. 146 */ 147 n = kmalloc(sizeof *n, GFP_KERNEL); 148 if (!n) 149 return -ENOMEM; 150 151 n->addr = (Elf_Addr *)location; 152 n->value = v; 153 n->next = mips_hi16_list; 154 mips_hi16_list = n; 155 156 return 0; 157 } 158 159 static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v) 160 { 161 *location = (*location & 0xffff0000) | 162 ((((long long) v + 0x8000LL) >> 16) & 0xffff); 163 164 return 0; 165 } 166 167 static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v) 168 { 169 unsigned long insnlo = *location; 170 Elf_Addr val, vallo; 171 172 /* Sign extend the addend we extract from the lo insn. */ 173 vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000; 174 175 if (mips_hi16_list != NULL) { 176 struct mips_hi16 *l; 177 178 l = mips_hi16_list; 179 while (l != NULL) { 180 struct mips_hi16 *next; 181 unsigned long insn; 182 183 /* 184 * The value for the HI16 had best be the same. 185 */ 186 if (v != l->value) 187 goto out_danger; 188 189 /* 190 * Do the HI16 relocation. Note that we actually don't 191 * need to know anything about the LO16 itself, except 192 * where to find the low 16 bits of the addend needed 193 * by the LO16. 194 */ 195 insn = *l->addr; 196 val = ((insn & 0xffff) << 16) + vallo; 197 val += v; 198 199 /* 200 * Account for the sign extension that will happen in 201 * the low bits. 202 */ 203 val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff; 204 205 insn = (insn & ~0xffff) | val; 206 *l->addr = insn; 207 208 next = l->next; 209 kfree(l); 210 l = next; 211 } 212 213 mips_hi16_list = NULL; 214 } 215 216 /* 217 * Ok, we're done with the HI16 relocs. Now deal with the LO16. 218 */ 219 val = v + vallo; 220 insnlo = (insnlo & ~0xffff) | (val & 0xffff); 221 *location = insnlo; 222 223 return 0; 224 225 out_danger: 226 printk(KERN_ERR "module %s: dangerous " "relocation\n", me->name); 227 228 return -ENOEXEC; 229 } 230 231 static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v) 232 { 233 *location = (*location & 0xffff0000) | (v & 0xffff); 234 235 return 0; 236 } 237 238 static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v) 239 { 240 *(Elf_Addr *)location = v; 241 242 return 0; 243 } 244 245 static int apply_r_mips_higher_rela(struct module *me, u32 *location, 246 Elf_Addr v) 247 { 248 *location = (*location & 0xffff0000) | 249 ((((long long) v + 0x80008000LL) >> 32) & 0xffff); 250 251 return 0; 252 } 253 254 static int apply_r_mips_highest_rela(struct module *me, u32 *location, 255 Elf_Addr v) 256 { 257 *location = (*location & 0xffff0000) | 258 ((((long long) v + 0x800080008000LL) >> 48) & 0xffff); 259 260 return 0; 261 } 262 263 static int (*reloc_handlers_rel[]) (struct module *me, u32 *location, 264 Elf_Addr v) = { 265 [R_MIPS_NONE] = apply_r_mips_none, 266 [R_MIPS_32] = apply_r_mips_32_rel, 267 [R_MIPS_26] = apply_r_mips_26_rel, 268 [R_MIPS_HI16] = apply_r_mips_hi16_rel, 269 [R_MIPS_LO16] = apply_r_mips_lo16_rel 270 }; 271 272 static int (*reloc_handlers_rela[]) (struct module *me, u32 *location, 273 Elf_Addr v) = { 274 [R_MIPS_NONE] = apply_r_mips_none, 275 [R_MIPS_32] = apply_r_mips_32_rela, 276 [R_MIPS_26] = apply_r_mips_26_rela, 277 [R_MIPS_HI16] = apply_r_mips_hi16_rela, 278 [R_MIPS_LO16] = apply_r_mips_lo16_rela, 279 [R_MIPS_64] = apply_r_mips_64_rela, 280 [R_MIPS_HIGHER] = apply_r_mips_higher_rela, 281 [R_MIPS_HIGHEST] = apply_r_mips_highest_rela 282 }; 283 284 int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, 285 unsigned int symindex, unsigned int relsec, 286 struct module *me) 287 { 288 Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr; 289 Elf_Sym *sym; 290 u32 *location; 291 unsigned int i; 292 Elf_Addr v; 293 int res; 294 295 pr_debug("Applying relocate section %u to %u\n", relsec, 296 sechdrs[relsec].sh_info); 297 298 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 299 /* This is where to make the change */ 300 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 301 + rel[i].r_offset; 302 /* This is the symbol it is referring to */ 303 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 304 + ELF_MIPS_R_SYM(rel[i]); 305 if (!sym->st_value) { 306 /* Ignore unresolved weak symbol */ 307 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 308 continue; 309 printk(KERN_WARNING "%s: Unknown symbol %s\n", 310 me->name, strtab + sym->st_name); 311 return -ENOENT; 312 } 313 314 v = sym->st_value; 315 316 res = reloc_handlers_rel[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 317 if (res) 318 return res; 319 } 320 321 return 0; 322 } 323 324 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 325 unsigned int symindex, unsigned int relsec, 326 struct module *me) 327 { 328 Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr; 329 Elf_Sym *sym; 330 u32 *location; 331 unsigned int i; 332 Elf_Addr v; 333 int res; 334 335 pr_debug("Applying relocate section %u to %u\n", relsec, 336 sechdrs[relsec].sh_info); 337 338 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 339 /* This is where to make the change */ 340 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 341 + rel[i].r_offset; 342 /* This is the symbol it is referring to */ 343 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 344 + ELF_MIPS_R_SYM(rel[i]); 345 if (!sym->st_value) { 346 /* Ignore unresolved weak symbol */ 347 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 348 continue; 349 printk(KERN_WARNING "%s: Unknown symbol %s\n", 350 me->name, strtab + sym->st_name); 351 return -ENOENT; 352 } 353 354 v = sym->st_value + rel[i].r_addend; 355 356 res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 357 if (res) 358 return res; 359 } 360 361 return 0; 362 } 363 364 /* Given an address, look for it in the module exception tables. */ 365 const struct exception_table_entry *search_module_dbetables(unsigned long addr) 366 { 367 unsigned long flags; 368 const struct exception_table_entry *e = NULL; 369 struct mod_arch_specific *dbe; 370 371 spin_lock_irqsave(&dbe_lock, flags); 372 list_for_each_entry(dbe, &dbe_list, dbe_list) { 373 e = search_extable(dbe->dbe_start, dbe->dbe_end - 1, addr); 374 if (e) 375 break; 376 } 377 spin_unlock_irqrestore(&dbe_lock, flags); 378 379 /* Now, if we found one, we are running inside it now, hence 380 we cannot unload the module, hence no refcnt needed. */ 381 return e; 382 } 383 384 /* Put in dbe list if necessary. */ 385 int module_finalize(const Elf_Ehdr *hdr, 386 const Elf_Shdr *sechdrs, 387 struct module *me) 388 { 389 const Elf_Shdr *s; 390 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 391 392 INIT_LIST_HEAD(&me->arch.dbe_list); 393 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { 394 if (strcmp("__dbe_table", secstrings + s->sh_name) != 0) 395 continue; 396 me->arch.dbe_start = (void *)s->sh_addr; 397 me->arch.dbe_end = (void *)s->sh_addr + s->sh_size; 398 spin_lock_irq(&dbe_lock); 399 list_add(&me->arch.dbe_list, &dbe_list); 400 spin_unlock_irq(&dbe_lock); 401 } 402 return 0; 403 } 404 405 void module_arch_cleanup(struct module *mod) 406 { 407 spin_lock_irq(&dbe_lock); 408 list_del(&mod->arch.dbe_list); 409 spin_unlock_irq(&dbe_lock); 410 } 411