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