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#include <asm/pgtable.h> /* MODULE_START */ 33 34struct mips_hi16 { 35 struct mips_hi16 *next; 36 Elf_Addr *addr; 37 Elf_Addr value; 38}; 39 40static struct mips_hi16 *mips_hi16_list; 41 42static LIST_HEAD(dbe_list); 43static DEFINE_SPINLOCK(dbe_lock); 44 45void *module_alloc(unsigned long size) 46{ 47#ifdef MODULE_START 48 struct vm_struct *area; 49 50 size = PAGE_ALIGN(size); 51 if (!size) 52 return NULL; 53 54 area = __get_vm_area(size, VM_ALLOC, MODULE_START, MODULE_END); 55 if (!area) 56 return NULL; 57 58 return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL); 59#else 60 if (size == 0) 61 return NULL; 62 return vmalloc(size); 63#endif 64} 65 66/* Free memory returned from module_alloc */ 67void module_free(struct module *mod, void *module_region) 68{ 69 vfree(module_region); 70} 71 72int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 73 char *secstrings, struct module *mod) 74{ 75 return 0; 76} 77 78static int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v) 79{ 80 return 0; 81} 82 83static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v) 84{ 85 *location += v; 86 87 return 0; 88} 89 90static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v) 91{ 92 *location = v; 93 94 return 0; 95} 96 97static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v) 98{ 99 if (v % 4) { 100 printk(KERN_ERR "module %s: dangerous relocation\n", 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) | 112 ((*location + (v >> 2)) & 0x03ffffff); 113 114 return 0; 115} 116 117static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v) 118{ 119 if (v % 4) { 120 printk(KERN_ERR "module %s: dangerous relocation\n", me->name); 121 return -ENOEXEC; 122 } 123 124 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) { 125 printk(KERN_ERR 126 "module %s: relocation overflow\n", 127 me->name); 128 return -ENOEXEC; 129 } 130 131 *location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff); 132 133 return 0; 134} 135 136static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v) 137{ 138 struct mips_hi16 *n; 139 140 /* 141 * We cannot relocate this one now because we don't know the value of 142 * the carry we need to add. Save the information, and let LO16 do the 143 * actual relocation. 144 */ 145 n = kmalloc(sizeof *n, GFP_KERNEL); 146 if (!n) 147 return -ENOMEM; 148 149 n->addr = (Elf_Addr *)location; 150 n->value = v; 151 n->next = mips_hi16_list; 152 mips_hi16_list = n; 153 154 return 0; 155} 156 157static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v) 158{ 159 *location = (*location & 0xffff0000) | 160 ((((long long) v + 0x8000LL) >> 16) & 0xffff); 161 162 return 0; 163} 164 165static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v) 166{ 167 unsigned long insnlo = *location; 168 Elf_Addr val, vallo; 169 170 /* Sign extend the addend we extract from the lo insn. */ 171 vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000; 172 173 if (mips_hi16_list != NULL) { 174 struct mips_hi16 *l; 175 176 l = mips_hi16_list; 177 while (l != NULL) { 178 struct mips_hi16 *next; 179 unsigned long insn; 180 181 /* 182 * The value for the HI16 had best be the same. 183 */ 184 if (v != l->value) 185 goto out_danger; 186 187 /* 188 * Do the HI16 relocation. Note that we actually don't 189 * need to know anything about the LO16 itself, except 190 * where to find the low 16 bits of the addend needed 191 * by the LO16. 192 */ 193 insn = *l->addr; 194 val = ((insn & 0xffff) << 16) + vallo; 195 val += v; 196 197 /* 198 * Account for the sign extension that will happen in 199 * the low bits. 200 */ 201 val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff; 202 203 insn = (insn & ~0xffff) | val; 204 *l->addr = insn; 205 206 next = l->next; 207 kfree(l); 208 l = next; 209 } 210 211 mips_hi16_list = NULL; 212 } 213 214 /* 215 * Ok, we're done with the HI16 relocs. Now deal with the LO16. 216 */ 217 val = v + vallo; 218 insnlo = (insnlo & ~0xffff) | (val & 0xffff); 219 *location = insnlo; 220 221 return 0; 222 223out_danger: 224 printk(KERN_ERR "module %s: dangerous " "relocation\n", me->name); 225 226 return -ENOEXEC; 227} 228 229static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v) 230{ 231 *location = (*location & 0xffff0000) | (v & 0xffff); 232 233 return 0; 234} 235 236static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v) 237{ 238 *(Elf_Addr *)location = v; 239 240 return 0; 241} 242 243static int apply_r_mips_higher_rela(struct module *me, u32 *location, 244 Elf_Addr v) 245{ 246 *location = (*location & 0xffff0000) | 247 ((((long long) v + 0x80008000LL) >> 32) & 0xffff); 248 249 return 0; 250} 251 252static int apply_r_mips_highest_rela(struct module *me, u32 *location, 253 Elf_Addr v) 254{ 255 *location = (*location & 0xffff0000) | 256 ((((long long) v + 0x800080008000LL) >> 48) & 0xffff); 257 258 return 0; 259} 260 261static int (*reloc_handlers_rel[]) (struct module *me, u32 *location, 262 Elf_Addr v) = { 263 [R_MIPS_NONE] = apply_r_mips_none, 264 [R_MIPS_32] = apply_r_mips_32_rel, 265 [R_MIPS_26] = apply_r_mips_26_rel, 266 [R_MIPS_HI16] = apply_r_mips_hi16_rel, 267 [R_MIPS_LO16] = apply_r_mips_lo16_rel 268}; 269 270static int (*reloc_handlers_rela[]) (struct module *me, u32 *location, 271 Elf_Addr v) = { 272 [R_MIPS_NONE] = apply_r_mips_none, 273 [R_MIPS_32] = apply_r_mips_32_rela, 274 [R_MIPS_26] = apply_r_mips_26_rela, 275 [R_MIPS_HI16] = apply_r_mips_hi16_rela, 276 [R_MIPS_LO16] = apply_r_mips_lo16_rela, 277 [R_MIPS_64] = apply_r_mips_64_rela, 278 [R_MIPS_HIGHER] = apply_r_mips_higher_rela, 279 [R_MIPS_HIGHEST] = apply_r_mips_highest_rela 280}; 281 282int apply_relocate(Elf_Shdr *sechdrs, const char *strtab, 283 unsigned int symindex, unsigned int relsec, 284 struct module *me) 285{ 286 Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr; 287 Elf_Sym *sym; 288 u32 *location; 289 unsigned int i; 290 Elf_Addr v; 291 int res; 292 293 pr_debug("Applying relocate section %u to %u\n", relsec, 294 sechdrs[relsec].sh_info); 295 296 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 297 /* This is where to make the change */ 298 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 299 + rel[i].r_offset; 300 /* This is the symbol it is referring to */ 301 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 302 + ELF_MIPS_R_SYM(rel[i]); 303 if (!sym->st_value) { 304 /* Ignore unresolved weak symbol */ 305 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 306 continue; 307 printk(KERN_WARNING "%s: Unknown symbol %s\n", 308 me->name, strtab + sym->st_name); 309 return -ENOENT; 310 } 311 312 v = sym->st_value; 313 314 res = reloc_handlers_rel[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 315 if (res) 316 return res; 317 } 318 319 return 0; 320} 321 322int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 323 unsigned int symindex, unsigned int relsec, 324 struct module *me) 325{ 326 Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr; 327 Elf_Sym *sym; 328 u32 *location; 329 unsigned int i; 330 Elf_Addr v; 331 int res; 332 333 pr_debug("Applying relocate section %u to %u\n", relsec, 334 sechdrs[relsec].sh_info); 335 336 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { 337 /* This is where to make the change */ 338 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr 339 + rel[i].r_offset; 340 /* This is the symbol it is referring to */ 341 sym = (Elf_Sym *)sechdrs[symindex].sh_addr 342 + ELF_MIPS_R_SYM(rel[i]); 343 if (!sym->st_value) { 344 /* Ignore unresolved weak symbol */ 345 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) 346 continue; 347 printk(KERN_WARNING "%s: Unknown symbol %s\n", 348 me->name, strtab + sym->st_name); 349 return -ENOENT; 350 } 351 352 v = sym->st_value + rel[i].r_addend; 353 354 res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v); 355 if (res) 356 return res; 357 } 358 359 return 0; 360} 361 362/* Given an address, look for it in the module exception tables. */ 363const struct exception_table_entry *search_module_dbetables(unsigned long addr) 364{ 365 unsigned long flags; 366 const struct exception_table_entry *e = NULL; 367 struct mod_arch_specific *dbe; 368 369 spin_lock_irqsave(&dbe_lock, flags); 370 list_for_each_entry(dbe, &dbe_list, dbe_list) { 371 e = search_extable(dbe->dbe_start, dbe->dbe_end - 1, addr); 372 if (e) 373 break; 374 } 375 spin_unlock_irqrestore(&dbe_lock, flags); 376 377 /* Now, if we found one, we are running inside it now, hence 378 we cannot unload the module, hence no refcnt needed. */ 379 return e; 380} 381 382/* Put in dbe list if neccessary. */ 383int module_finalize(const Elf_Ehdr *hdr, 384 const Elf_Shdr *sechdrs, 385 struct module *me) 386{ 387 const Elf_Shdr *s; 388 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 389 390 INIT_LIST_HEAD(&me->arch.dbe_list); 391 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { 392 if (strcmp("__dbe_table", secstrings + s->sh_name) != 0) 393 continue; 394 me->arch.dbe_start = (void *)s->sh_addr; 395 me->arch.dbe_end = (void *)s->sh_addr + s->sh_size; 396 spin_lock_irq(&dbe_lock); 397 list_add(&me->arch.dbe_list, &dbe_list); 398 spin_unlock_irq(&dbe_lock); 399 } 400 return 0; 401} 402 403void module_arch_cleanup(struct module *mod) 404{ 405 spin_lock_irq(&dbe_lock); 406 list_del(&mod->arch.dbe_list); 407 spin_unlock_irq(&dbe_lock); 408} 409