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/vmalloc.h> 26 #include <linux/slab.h> 27 #include <linux/fs.h> 28 #include <linux/string.h> 29 #include <linux/kernel.h> 30 #include <linux/module.h> 31 #include <linux/spinlock.h> 32 33 struct mips_hi16 { 34 struct mips_hi16 *next; 35 Elf_Addr *addr; 36 Elf_Addr value; 37 }; 38 39 static struct mips_hi16 *mips_hi16_list; 40 41 static LIST_HEAD(dbe_list); 42 static DEFINE_SPINLOCK(dbe_lock); 43 44 void *module_alloc(unsigned long size) 45 { 46 if (size == 0) 47 return NULL; 48 return vmalloc(size); 49 } 50 51 /* Free memory returned from module_alloc */ 52 void module_free(struct module *mod, void *module_region) 53 { 54 vfree(module_region); 55 /* FIXME: If module_region == mod->init_region, trim exception 56 table entries. */ 57 } 58 59 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 60 char *secstrings, struct module *mod) 61 { 62 return 0; 63 } 64 65 static int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v) 66 { 67 return 0; 68 } 69 70 static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v) 71 { 72 *location += v; 73 74 return 0; 75 } 76 77 static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v) 78 { 79 *location = v; 80 81 return 0; 82 } 83 84 static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v) 85 { 86 if (v % 4) { 87 printk(KERN_ERR "module %s: dangerous relocation\n", me->name); 88 return -ENOEXEC; 89 } 90 91 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 92 printk(KERN_ERR 93 "module %s: relocation overflow\n", 94 me->name); 95 return -ENOEXEC; 96 } 97 98 *location = (*location & ~0x03ffffff) | 99 ((*location + (v >> 2)) & 0x03ffffff); 100 101 return 0; 102 } 103 104 static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v) 105 { 106 if (v % 4) { 107 printk(KERN_ERR "module %s: dangerous relocation\n", me->name); 108 return -ENOEXEC; 109 } 110 111 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 112 printk(KERN_ERR 113 "module %s: relocation overflow\n", 114 me->name); 115 return -ENOEXEC; 116 } 117 118 *location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff); 119 120 return 0; 121 } 122 123 static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v) 124 { 125 struct mips_hi16 *n; 126 127 /* 128 * We cannot relocate this one now because we don't know the value of 129 * the carry we need to add. Save the information, and let LO16 do the 130 * actual relocation. 131 */ 132 n = kmalloc(sizeof *n, GFP_KERNEL); 133 if (!n) 134 return -ENOMEM; 135 136 n->addr = (Elf_Addr *)location; 137 n->value = v; 138 n->next = mips_hi16_list; 139 mips_hi16_list = n; 140 141 return 0; 142 } 143 144 static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v) 145 { 146 *location = (*location & 0xffff0000) | 147 ((((long long) v + 0x8000LL) >> 16) & 0xffff); 148 149 return 0; 150 } 151 152 static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v) 153 { 154 unsigned long insnlo = *location; 155 Elf_Addr val, vallo; 156 157 /* Sign extend the addend we extract from the lo insn. */ 158 vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000; 159 160 if (mips_hi16_list != NULL) { 161 struct mips_hi16 *l; 162 163 l = mips_hi16_list; 164 while (l != NULL) { 165 struct mips_hi16 *next; 166 unsigned long insn; 167 168 /* 169 * The value for the HI16 had best be the same. 170 */ 171 if (v != l->value) 172 goto out_danger; 173 174 /* 175 * Do the HI16 relocation. Note that we actually don't 176 * need to know anything about the LO16 itself, except 177 * where to find the low 16 bits of the addend needed 178 * by the LO16. 179 */ 180 insn = *l->addr; 181 val = ((insn & 0xffff) << 16) + vallo; 182 val += v; 183 184 /* 185 * Account for the sign extension that will happen in 186 * the low bits. 187 */ 188 val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff; 189 190 insn = (insn & ~0xffff) | val; 191 *l->addr = insn; 192 193 next = l->next; 194 kfree(l); 195 l = next; 196 } 197 198 mips_hi16_list = NULL; 199 } 200 201 /* 202 * Ok, we're done with the HI16 relocs. Now deal with the LO16. 203 */ 204 val = v + vallo; 205 insnlo = (insnlo & ~0xffff) | (val & 0xffff); 206 *location = insnlo; 207 208 return 0; 209 210 out_danger: 211 printk(KERN_ERR "module %s: dangerous " "relocation\n", me->name); 212 213 return -ENOEXEC; 214 } 215 216 static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v) 217 { 218 *location = (*location & 0xffff0000) | (v & 0xffff); 219 220 return 0; 221 } 222 223 static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v) 224 { 225 *(Elf_Addr *)location = v; 226 227 return 0; 228 } 229 230 static int apply_r_mips_higher_rela(struct module *me, u32 *location, 231 Elf_Addr v) 232 { 233 *location = (*location & 0xffff0000) | 234 ((((long long) v + 0x80008000LL) >> 32) & 0xffff); 235 236 return 0; 237 } 238 239 static int apply_r_mips_highest_rela(struct module *me, u32 *location, 240 Elf_Addr v) 241 { 242 *location = (*location & 0xffff0000) | 243 ((((long long) v + 0x800080008000LL) >> 48) & 0xffff); 244 245 return 0; 246 } 247 248 static int (*reloc_handlers_rel[]) (struct module *me, u32 *location, 249 Elf_Addr v) = { 250 [R_MIPS_NONE] = apply_r_mips_none, 251 [R_MIPS_32] = apply_r_mips_32_rel, 252 [R_MIPS_26] = apply_r_mips_26_rel, 253 [R_MIPS_HI16] = apply_r_mips_hi16_rel, 254 [R_MIPS_LO16] = apply_r_mips_lo16_rel 255 }; 256 257 static int (*reloc_handlers_rela[]) (struct module *me, u32 *location, 258 Elf_Addr v) = { 259 [R_MIPS_NONE] = apply_r_mips_none, 260 [R_MIPS_32] = apply_r_mips_32_rela, 261 [R_MIPS_26] = apply_r_mips_26_rela, 262 [R_MIPS_HI16] = apply_r_mips_hi16_rela, 263 [R_MIPS_LO16] = apply_r_mips_lo16_rela, 264 [R_MIPS_64] = apply_r_mips_64_rela, 265 [R_MIPS_HIGHER] = apply_r_mips_higher_rela, 266 [R_MIPS_HIGHEST] = apply_r_mips_highest_rela 267 }; 268 269 int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, 270 unsigned int symindex, unsigned int relsec, 271 struct module *me) 272 { 273 Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr; 274 Elf_Sym *sym; 275 u32 *location; 276 unsigned int i; 277 Elf_Addr v; 278 int res; 279 280 pr_debug("Applying relocate section %u to %u\n", relsec, 281 sechdrs[relsec].sh_info); 282 283 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 284 /* This is where to make the change */ 285 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 286 + rel[i].r_offset; 287 /* This is the symbol it is referring to */ 288 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 289 + ELF_MIPS_R_SYM(rel[i]); 290 if (!sym->st_value) { 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 (!sym->st_value) { 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 neccessary. */ 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 INIT_LIST_HEAD(&me->arch.dbe_list); 372 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { 373 if (strcmp("__dbe_table", secstrings + s->sh_name) != 0) 374 continue; 375 me->arch.dbe_start = (void *)s->sh_addr; 376 me->arch.dbe_end = (void *)s->sh_addr + s->sh_size; 377 spin_lock_irq(&dbe_lock); 378 list_add(&me->arch.dbe_list, &dbe_list); 379 spin_unlock_irq(&dbe_lock); 380 } 381 return 0; 382 } 383 384 void module_arch_cleanup(struct module *mod) 385 { 386 spin_lock_irq(&dbe_lock); 387 list_del(&mod->arch.dbe_list); 388 spin_unlock_irq(&dbe_lock); 389 } 390