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 LIST_HEAD(dbe_list); 43 static DEFINE_SPINLOCK(dbe_lock); 44 45 #ifdef MODULE_START 46 void *module_alloc(unsigned long size) 47 { 48 return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END, 49 GFP_KERNEL, PAGE_KERNEL, -1, 50 __builtin_return_address(0)); 51 } 52 #endif 53 54 static int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v) 55 { 56 return 0; 57 } 58 59 static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v) 60 { 61 *location += v; 62 63 return 0; 64 } 65 66 static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v) 67 { 68 *location = v; 69 70 return 0; 71 } 72 73 static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v) 74 { 75 if (v % 4) { 76 pr_err("module %s: dangerous R_MIPS_26 REL relocation\n", 77 me->name); 78 return -ENOEXEC; 79 } 80 81 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 82 printk(KERN_ERR 83 "module %s: relocation overflow\n", 84 me->name); 85 return -ENOEXEC; 86 } 87 88 *location = (*location & ~0x03ffffff) | 89 ((*location + (v >> 2)) & 0x03ffffff); 90 91 return 0; 92 } 93 94 static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v) 95 { 96 if (v % 4) { 97 pr_err("module %s: dangerous R_MIPS_26 RELArelocation\n", 98 me->name); 99 return -ENOEXEC; 100 } 101 102 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 103 printk(KERN_ERR 104 "module %s: relocation overflow\n", 105 me->name); 106 return -ENOEXEC; 107 } 108 109 *location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff); 110 111 return 0; 112 } 113 114 static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v) 115 { 116 struct mips_hi16 *n; 117 118 /* 119 * We cannot relocate this one now because we don't know the value of 120 * the carry we need to add. Save the information, and let LO16 do the 121 * actual relocation. 122 */ 123 n = kmalloc(sizeof *n, GFP_KERNEL); 124 if (!n) 125 return -ENOMEM; 126 127 n->addr = (Elf_Addr *)location; 128 n->value = v; 129 n->next = me->arch.r_mips_hi16_list; 130 me->arch.r_mips_hi16_list = n; 131 132 return 0; 133 } 134 135 static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v) 136 { 137 *location = (*location & 0xffff0000) | 138 ((((long long) v + 0x8000LL) >> 16) & 0xffff); 139 140 return 0; 141 } 142 143 static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v) 144 { 145 unsigned long insnlo = *location; 146 Elf_Addr val, vallo; 147 struct mips_hi16 *l, *next; 148 149 /* Sign extend the addend we extract from the lo insn. */ 150 vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000; 151 152 if (me->arch.r_mips_hi16_list != NULL) { 153 154 l = me->arch.r_mips_hi16_list; 155 while (l != NULL) { 156 unsigned long insn; 157 158 /* 159 * The value for the HI16 had best be the same. 160 */ 161 if (v != l->value) 162 goto out_danger; 163 164 /* 165 * Do the HI16 relocation. Note that we actually don't 166 * need to know anything about the LO16 itself, except 167 * where to find the low 16 bits of the addend needed 168 * by the LO16. 169 */ 170 insn = *l->addr; 171 val = ((insn & 0xffff) << 16) + vallo; 172 val += v; 173 174 /* 175 * Account for the sign extension that will happen in 176 * the low bits. 177 */ 178 val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff; 179 180 insn = (insn & ~0xffff) | val; 181 *l->addr = insn; 182 183 next = l->next; 184 kfree(l); 185 l = next; 186 } 187 188 me->arch.r_mips_hi16_list = NULL; 189 } 190 191 /* 192 * Ok, we're done with the HI16 relocs. Now deal with the LO16. 193 */ 194 val = v + vallo; 195 insnlo = (insnlo & ~0xffff) | (val & 0xffff); 196 *location = insnlo; 197 198 return 0; 199 200 out_danger: 201 while (l) { 202 next = l->next; 203 kfree(l); 204 l = next; 205 } 206 207 pr_err("module %s: dangerous R_MIPS_LO16 REL relocation\n", me->name); 208 209 return -ENOEXEC; 210 } 211 212 static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v) 213 { 214 *location = (*location & 0xffff0000) | (v & 0xffff); 215 216 return 0; 217 } 218 219 static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v) 220 { 221 *(Elf_Addr *)location = v; 222 223 return 0; 224 } 225 226 static int apply_r_mips_higher_rela(struct module *me, u32 *location, 227 Elf_Addr v) 228 { 229 *location = (*location & 0xffff0000) | 230 ((((long long) v + 0x80008000LL) >> 32) & 0xffff); 231 232 return 0; 233 } 234 235 static int apply_r_mips_highest_rela(struct module *me, u32 *location, 236 Elf_Addr v) 237 { 238 *location = (*location & 0xffff0000) | 239 ((((long long) v + 0x800080008000LL) >> 48) & 0xffff); 240 241 return 0; 242 } 243 244 static int (*reloc_handlers_rel[]) (struct module *me, u32 *location, 245 Elf_Addr v) = { 246 [R_MIPS_NONE] = apply_r_mips_none, 247 [R_MIPS_32] = apply_r_mips_32_rel, 248 [R_MIPS_26] = apply_r_mips_26_rel, 249 [R_MIPS_HI16] = apply_r_mips_hi16_rel, 250 [R_MIPS_LO16] = apply_r_mips_lo16_rel 251 }; 252 253 static int (*reloc_handlers_rela[]) (struct module *me, u32 *location, 254 Elf_Addr v) = { 255 [R_MIPS_NONE] = apply_r_mips_none, 256 [R_MIPS_32] = apply_r_mips_32_rela, 257 [R_MIPS_26] = apply_r_mips_26_rela, 258 [R_MIPS_HI16] = apply_r_mips_hi16_rela, 259 [R_MIPS_LO16] = apply_r_mips_lo16_rela, 260 [R_MIPS_64] = apply_r_mips_64_rela, 261 [R_MIPS_HIGHER] = apply_r_mips_higher_rela, 262 [R_MIPS_HIGHEST] = apply_r_mips_highest_rela 263 }; 264 265 int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, 266 unsigned int symindex, unsigned int relsec, 267 struct module *me) 268 { 269 Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr; 270 Elf_Sym *sym; 271 u32 *location; 272 unsigned int i; 273 Elf_Addr v; 274 int res; 275 276 pr_debug("Applying relocate section %u to %u\n", relsec, 277 sechdrs[relsec].sh_info); 278 279 me->arch.r_mips_hi16_list = NULL; 280 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 281 /* This is where to make the change */ 282 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 283 + rel[i].r_offset; 284 /* This is the symbol it is referring to */ 285 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 286 + ELF_MIPS_R_SYM(rel[i]); 287 if (IS_ERR_VALUE(sym->st_value)) { 288 /* Ignore unresolved weak symbol */ 289 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 290 continue; 291 printk(KERN_WARNING "%s: Unknown symbol %s\n", 292 me->name, strtab + sym->st_name); 293 return -ENOENT; 294 } 295 296 v = sym->st_value; 297 298 res = reloc_handlers_rel[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 299 if (res) 300 return res; 301 } 302 303 return 0; 304 } 305 306 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 307 unsigned int symindex, unsigned int relsec, 308 struct module *me) 309 { 310 Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr; 311 Elf_Sym *sym; 312 u32 *location; 313 unsigned int i; 314 Elf_Addr v; 315 int res; 316 317 pr_debug("Applying relocate section %u to %u\n", relsec, 318 sechdrs[relsec].sh_info); 319 320 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 321 /* This is where to make the change */ 322 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 323 + rel[i].r_offset; 324 /* This is the symbol it is referring to */ 325 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 326 + ELF_MIPS_R_SYM(rel[i]); 327 if (IS_ERR_VALUE(sym->st_value)) { 328 /* Ignore unresolved weak symbol */ 329 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 330 continue; 331 printk(KERN_WARNING "%s: Unknown symbol %s\n", 332 me->name, strtab + sym->st_name); 333 return -ENOENT; 334 } 335 336 v = sym->st_value + rel[i].r_addend; 337 338 res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 339 if (res) 340 return res; 341 } 342 343 return 0; 344 } 345 346 /* Given an address, look for it in the module exception tables. */ 347 const struct exception_table_entry *search_module_dbetables(unsigned long addr) 348 { 349 unsigned long flags; 350 const struct exception_table_entry *e = NULL; 351 struct mod_arch_specific *dbe; 352 353 spin_lock_irqsave(&dbe_lock, flags); 354 list_for_each_entry(dbe, &dbe_list, dbe_list) { 355 e = search_extable(dbe->dbe_start, dbe->dbe_end - 1, addr); 356 if (e) 357 break; 358 } 359 spin_unlock_irqrestore(&dbe_lock, flags); 360 361 /* Now, if we found one, we are running inside it now, hence 362 we cannot unload the module, hence no refcnt needed. */ 363 return e; 364 } 365 366 /* Put in dbe list if necessary. */ 367 int module_finalize(const Elf_Ehdr *hdr, 368 const Elf_Shdr *sechdrs, 369 struct module *me) 370 { 371 const Elf_Shdr *s; 372 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 373 374 /* Make jump label nops. */ 375 jump_label_apply_nops(me); 376 377 INIT_LIST_HEAD(&me->arch.dbe_list); 378 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { 379 if (strcmp("__dbe_table", secstrings + s->sh_name) != 0) 380 continue; 381 me->arch.dbe_start = (void *)s->sh_addr; 382 me->arch.dbe_end = (void *)s->sh_addr + s->sh_size; 383 spin_lock_irq(&dbe_lock); 384 list_add(&me->arch.dbe_list, &dbe_list); 385 spin_unlock_irq(&dbe_lock); 386 } 387 return 0; 388 } 389 390 void module_arch_cleanup(struct module *mod) 391 { 392 spin_lock_irq(&dbe_lock); 393 list_del(&mod->arch.dbe_list); 394 spin_unlock_irq(&dbe_lock); 395 } 396