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