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