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 struct vm_struct *area; 50 51 size = PAGE_ALIGN(size); 52 if (!size) 53 return NULL; 54 55 area = __get_vm_area(size, VM_ALLOC, MODULE_START, MODULE_END); 56 if (!area) 57 return NULL; 58 59 return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL); 60 #else 61 if (size == 0) 62 return NULL; 63 return vmalloc(size); 64 #endif 65 } 66 67 /* Free memory returned from module_alloc */ 68 void module_free(struct module *mod, void *module_region) 69 { 70 vfree(module_region); 71 /* FIXME: If module_region == mod->init_region, trim exception 72 table entries. */ 73 } 74 75 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 76 char *secstrings, struct module *mod) 77 { 78 return 0; 79 } 80 81 static int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v) 82 { 83 return 0; 84 } 85 86 static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v) 87 { 88 *location += v; 89 90 return 0; 91 } 92 93 static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v) 94 { 95 *location = v; 96 97 return 0; 98 } 99 100 static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v) 101 { 102 if (v % 4) { 103 printk(KERN_ERR "module %s: dangerous relocation\n", me->name); 104 return -ENOEXEC; 105 } 106 107 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 108 printk(KERN_ERR 109 "module %s: relocation overflow\n", 110 me->name); 111 return -ENOEXEC; 112 } 113 114 *location = (*location & ~0x03ffffff) | 115 ((*location + (v >> 2)) & 0x03ffffff); 116 117 return 0; 118 } 119 120 static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v) 121 { 122 if (v % 4) { 123 printk(KERN_ERR "module %s: dangerous relocation\n", me->name); 124 return -ENOEXEC; 125 } 126 127 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 128 printk(KERN_ERR 129 "module %s: relocation overflow\n", 130 me->name); 131 return -ENOEXEC; 132 } 133 134 *location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff); 135 136 return 0; 137 } 138 139 static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v) 140 { 141 struct mips_hi16 *n; 142 143 /* 144 * We cannot relocate this one now because we don't know the value of 145 * the carry we need to add. Save the information, and let LO16 do the 146 * actual relocation. 147 */ 148 n = kmalloc(sizeof *n, GFP_KERNEL); 149 if (!n) 150 return -ENOMEM; 151 152 n->addr = (Elf_Addr *)location; 153 n->value = v; 154 n->next = mips_hi16_list; 155 mips_hi16_list = n; 156 157 return 0; 158 } 159 160 static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v) 161 { 162 *location = (*location & 0xffff0000) | 163 ((((long long) v + 0x8000LL) >> 16) & 0xffff); 164 165 return 0; 166 } 167 168 static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v) 169 { 170 unsigned long insnlo = *location; 171 Elf_Addr val, vallo; 172 173 /* Sign extend the addend we extract from the lo insn. */ 174 vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000; 175 176 if (mips_hi16_list != NULL) { 177 struct mips_hi16 *l; 178 179 l = mips_hi16_list; 180 while (l != NULL) { 181 struct mips_hi16 *next; 182 unsigned long insn; 183 184 /* 185 * The value for the HI16 had best be the same. 186 */ 187 if (v != l->value) 188 goto out_danger; 189 190 /* 191 * Do the HI16 relocation. Note that we actually don't 192 * need to know anything about the LO16 itself, except 193 * where to find the low 16 bits of the addend needed 194 * by the LO16. 195 */ 196 insn = *l->addr; 197 val = ((insn & 0xffff) << 16) + vallo; 198 val += v; 199 200 /* 201 * Account for the sign extension that will happen in 202 * the low bits. 203 */ 204 val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff; 205 206 insn = (insn & ~0xffff) | val; 207 *l->addr = insn; 208 209 next = l->next; 210 kfree(l); 211 l = next; 212 } 213 214 mips_hi16_list = NULL; 215 } 216 217 /* 218 * Ok, we're done with the HI16 relocs. Now deal with the LO16. 219 */ 220 val = v + vallo; 221 insnlo = (insnlo & ~0xffff) | (val & 0xffff); 222 *location = insnlo; 223 224 return 0; 225 226 out_danger: 227 printk(KERN_ERR "module %s: dangerous " "relocation\n", me->name); 228 229 return -ENOEXEC; 230 } 231 232 static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v) 233 { 234 *location = (*location & 0xffff0000) | (v & 0xffff); 235 236 return 0; 237 } 238 239 static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v) 240 { 241 *(Elf_Addr *)location = v; 242 243 return 0; 244 } 245 246 static int apply_r_mips_higher_rela(struct module *me, u32 *location, 247 Elf_Addr v) 248 { 249 *location = (*location & 0xffff0000) | 250 ((((long long) v + 0x80008000LL) >> 32) & 0xffff); 251 252 return 0; 253 } 254 255 static int apply_r_mips_highest_rela(struct module *me, u32 *location, 256 Elf_Addr v) 257 { 258 *location = (*location & 0xffff0000) | 259 ((((long long) v + 0x800080008000LL) >> 48) & 0xffff); 260 261 return 0; 262 } 263 264 static int (*reloc_handlers_rel[]) (struct module *me, u32 *location, 265 Elf_Addr v) = { 266 [R_MIPS_NONE] = apply_r_mips_none, 267 [R_MIPS_32] = apply_r_mips_32_rel, 268 [R_MIPS_26] = apply_r_mips_26_rel, 269 [R_MIPS_HI16] = apply_r_mips_hi16_rel, 270 [R_MIPS_LO16] = apply_r_mips_lo16_rel 271 }; 272 273 static int (*reloc_handlers_rela[]) (struct module *me, u32 *location, 274 Elf_Addr v) = { 275 [R_MIPS_NONE] = apply_r_mips_none, 276 [R_MIPS_32] = apply_r_mips_32_rela, 277 [R_MIPS_26] = apply_r_mips_26_rela, 278 [R_MIPS_HI16] = apply_r_mips_hi16_rela, 279 [R_MIPS_LO16] = apply_r_mips_lo16_rela, 280 [R_MIPS_64] = apply_r_mips_64_rela, 281 [R_MIPS_HIGHER] = apply_r_mips_higher_rela, 282 [R_MIPS_HIGHEST] = apply_r_mips_highest_rela 283 }; 284 285 int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, 286 unsigned int symindex, unsigned int relsec, 287 struct module *me) 288 { 289 Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr; 290 Elf_Sym *sym; 291 u32 *location; 292 unsigned int i; 293 Elf_Addr v; 294 int res; 295 296 pr_debug("Applying relocate section %u to %u\n", relsec, 297 sechdrs[relsec].sh_info); 298 299 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 300 /* This is where to make the change */ 301 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 302 + rel[i].r_offset; 303 /* This is the symbol it is referring to */ 304 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 305 + ELF_MIPS_R_SYM(rel[i]); 306 if (!sym->st_value) { 307 /* Ignore unresolved weak symbol */ 308 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 309 continue; 310 printk(KERN_WARNING "%s: Unknown symbol %s\n", 311 me->name, strtab + sym->st_name); 312 return -ENOENT; 313 } 314 315 v = sym->st_value; 316 317 res = reloc_handlers_rel[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 318 if (res) 319 return res; 320 } 321 322 return 0; 323 } 324 325 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 326 unsigned int symindex, unsigned int relsec, 327 struct module *me) 328 { 329 Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr; 330 Elf_Sym *sym; 331 u32 *location; 332 unsigned int i; 333 Elf_Addr v; 334 int res; 335 336 pr_debug("Applying relocate section %u to %u\n", relsec, 337 sechdrs[relsec].sh_info); 338 339 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 340 /* This is where to make the change */ 341 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 342 + rel[i].r_offset; 343 /* This is the symbol it is referring to */ 344 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 345 + ELF_MIPS_R_SYM(rel[i]); 346 if (!sym->st_value) { 347 /* Ignore unresolved weak symbol */ 348 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 349 continue; 350 printk(KERN_WARNING "%s: Unknown symbol %s\n", 351 me->name, strtab + sym->st_name); 352 return -ENOENT; 353 } 354 355 v = sym->st_value + rel[i].r_addend; 356 357 res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 358 if (res) 359 return res; 360 } 361 362 return 0; 363 } 364 365 /* Given an address, look for it in the module exception tables. */ 366 const struct exception_table_entry *search_module_dbetables(unsigned long addr) 367 { 368 unsigned long flags; 369 const struct exception_table_entry *e = NULL; 370 struct mod_arch_specific *dbe; 371 372 spin_lock_irqsave(&dbe_lock, flags); 373 list_for_each_entry(dbe, &dbe_list, dbe_list) { 374 e = search_extable(dbe->dbe_start, dbe->dbe_end - 1, addr); 375 if (e) 376 break; 377 } 378 spin_unlock_irqrestore(&dbe_lock, flags); 379 380 /* Now, if we found one, we are running inside it now, hence 381 we cannot unload the module, hence no refcnt needed. */ 382 return e; 383 } 384 385 /* Put in dbe list if necessary. */ 386 int module_finalize(const Elf_Ehdr *hdr, 387 const Elf_Shdr *sechdrs, 388 struct module *me) 389 { 390 const Elf_Shdr *s; 391 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 392 393 INIT_LIST_HEAD(&me->arch.dbe_list); 394 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { 395 if (strcmp("__dbe_table", secstrings + s->sh_name) != 0) 396 continue; 397 me->arch.dbe_start = (void *)s->sh_addr; 398 me->arch.dbe_end = (void *)s->sh_addr + s->sh_size; 399 spin_lock_irq(&dbe_lock); 400 list_add(&me->arch.dbe_list, &dbe_list); 401 spin_unlock_irq(&dbe_lock); 402 } 403 return 0; 404 } 405 406 void module_arch_cleanup(struct module *mod) 407 { 408 spin_lock_irq(&dbe_lock); 409 list_del(&mod->arch.dbe_list); 410 spin_unlock_irq(&dbe_lock); 411 } 412