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