1 /* 2 * Kernel module help for s390. 3 * 4 * S390 version 5 * Copyright IBM Corp. 2002, 2003 6 * Author(s): Arnd Bergmann (arndb@de.ibm.com) 7 * Martin Schwidefsky (schwidefsky@de.ibm.com) 8 * 9 * based on i386 version 10 * Copyright (C) 2001 Rusty Russell. 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License as published by 14 * the Free Software Foundation; either version 2 of the License, or 15 * (at your option) any later version. 16 * 17 * This program is distributed in the hope that it will be useful, 18 * but WITHOUT ANY WARRANTY; without even the implied warranty of 19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 20 * GNU General Public License for more details. 21 * 22 * You should have received a copy of the GNU General Public License 23 * along with this program; if not, write to the Free Software 24 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 25 */ 26 #include <linux/module.h> 27 #include <linux/elf.h> 28 #include <linux/vmalloc.h> 29 #include <linux/fs.h> 30 #include <linux/string.h> 31 #include <linux/kernel.h> 32 #include <linux/moduleloader.h> 33 #include <linux/bug.h> 34 35 #if 0 36 #define DEBUGP printk 37 #else 38 #define DEBUGP(fmt , ...) 39 #endif 40 41 #ifndef CONFIG_64BIT 42 #define PLT_ENTRY_SIZE 12 43 #else /* CONFIG_64BIT */ 44 #define PLT_ENTRY_SIZE 20 45 #endif /* CONFIG_64BIT */ 46 47 #ifdef CONFIG_64BIT 48 void *module_alloc(unsigned long size) 49 { 50 if (PAGE_ALIGN(size) > MODULES_LEN) 51 return NULL; 52 return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, 53 GFP_KERNEL, PAGE_KERNEL, -1, 54 __builtin_return_address(0)); 55 } 56 #endif 57 58 /* Free memory returned from module_alloc */ 59 void module_free(struct module *mod, void *module_region) 60 { 61 if (mod) { 62 vfree(mod->arch.syminfo); 63 mod->arch.syminfo = NULL; 64 } 65 vfree(module_region); 66 } 67 68 static void check_rela(Elf_Rela *rela, struct module *me) 69 { 70 struct mod_arch_syminfo *info; 71 72 info = me->arch.syminfo + ELF_R_SYM (rela->r_info); 73 switch (ELF_R_TYPE (rela->r_info)) { 74 case R_390_GOT12: /* 12 bit GOT offset. */ 75 case R_390_GOT16: /* 16 bit GOT offset. */ 76 case R_390_GOT20: /* 20 bit GOT offset. */ 77 case R_390_GOT32: /* 32 bit GOT offset. */ 78 case R_390_GOT64: /* 64 bit GOT offset. */ 79 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */ 80 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */ 81 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */ 82 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */ 83 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */ 84 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */ 85 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */ 86 if (info->got_offset == -1UL) { 87 info->got_offset = me->arch.got_size; 88 me->arch.got_size += sizeof(void*); 89 } 90 break; 91 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */ 92 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */ 93 case R_390_PLT32: /* 32 bit PC relative PLT address. */ 94 case R_390_PLT64: /* 64 bit PC relative PLT address. */ 95 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */ 96 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */ 97 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */ 98 if (info->plt_offset == -1UL) { 99 info->plt_offset = me->arch.plt_size; 100 me->arch.plt_size += PLT_ENTRY_SIZE; 101 } 102 break; 103 case R_390_COPY: 104 case R_390_GLOB_DAT: 105 case R_390_JMP_SLOT: 106 case R_390_RELATIVE: 107 /* Only needed if we want to support loading of 108 modules linked with -shared. */ 109 break; 110 } 111 } 112 113 /* 114 * Account for GOT and PLT relocations. We can't add sections for 115 * got and plt but we can increase the core module size. 116 */ 117 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 118 char *secstrings, struct module *me) 119 { 120 Elf_Shdr *symtab; 121 Elf_Sym *symbols; 122 Elf_Rela *rela; 123 char *strings; 124 int nrela, i, j; 125 126 /* Find symbol table and string table. */ 127 symtab = NULL; 128 for (i = 0; i < hdr->e_shnum; i++) 129 switch (sechdrs[i].sh_type) { 130 case SHT_SYMTAB: 131 symtab = sechdrs + i; 132 break; 133 } 134 if (!symtab) { 135 printk(KERN_ERR "module %s: no symbol table\n", me->name); 136 return -ENOEXEC; 137 } 138 139 /* Allocate one syminfo structure per symbol. */ 140 me->arch.nsyms = symtab->sh_size / sizeof(Elf_Sym); 141 me->arch.syminfo = vmalloc(me->arch.nsyms * 142 sizeof(struct mod_arch_syminfo)); 143 if (!me->arch.syminfo) 144 return -ENOMEM; 145 symbols = (void *) hdr + symtab->sh_offset; 146 strings = (void *) hdr + sechdrs[symtab->sh_link].sh_offset; 147 for (i = 0; i < me->arch.nsyms; i++) { 148 if (symbols[i].st_shndx == SHN_UNDEF && 149 strcmp(strings + symbols[i].st_name, 150 "_GLOBAL_OFFSET_TABLE_") == 0) 151 /* "Define" it as absolute. */ 152 symbols[i].st_shndx = SHN_ABS; 153 me->arch.syminfo[i].got_offset = -1UL; 154 me->arch.syminfo[i].plt_offset = -1UL; 155 me->arch.syminfo[i].got_initialized = 0; 156 me->arch.syminfo[i].plt_initialized = 0; 157 } 158 159 /* Search for got/plt relocations. */ 160 me->arch.got_size = me->arch.plt_size = 0; 161 for (i = 0; i < hdr->e_shnum; i++) { 162 if (sechdrs[i].sh_type != SHT_RELA) 163 continue; 164 nrela = sechdrs[i].sh_size / sizeof(Elf_Rela); 165 rela = (void *) hdr + sechdrs[i].sh_offset; 166 for (j = 0; j < nrela; j++) 167 check_rela(rela + j, me); 168 } 169 170 /* Increase core size by size of got & plt and set start 171 offsets for got and plt. */ 172 me->core_size = ALIGN(me->core_size, 4); 173 me->arch.got_offset = me->core_size; 174 me->core_size += me->arch.got_size; 175 me->arch.plt_offset = me->core_size; 176 me->core_size += me->arch.plt_size; 177 return 0; 178 } 179 180 static int apply_rela_bits(Elf_Addr loc, Elf_Addr val, 181 int sign, int bits, int shift) 182 { 183 unsigned long umax; 184 long min, max; 185 186 if (val & ((1UL << shift) - 1)) 187 return -ENOEXEC; 188 if (sign) { 189 val = (Elf_Addr)(((long) val) >> shift); 190 min = -(1L << (bits - 1)); 191 max = (1L << (bits - 1)) - 1; 192 if ((long) val < min || (long) val > max) 193 return -ENOEXEC; 194 } else { 195 val >>= shift; 196 umax = ((1UL << (bits - 1)) << 1) - 1; 197 if ((unsigned long) val > umax) 198 return -ENOEXEC; 199 } 200 201 if (bits == 8) 202 *(unsigned char *) loc = val; 203 else if (bits == 12) 204 *(unsigned short *) loc = (val & 0xfff) | 205 (*(unsigned short *) loc & 0xf000); 206 else if (bits == 16) 207 *(unsigned short *) loc = val; 208 else if (bits == 20) 209 *(unsigned int *) loc = (val & 0xfff) << 16 | 210 (val & 0xff000) >> 4 | 211 (*(unsigned int *) loc & 0xf00000ff); 212 else if (bits == 32) 213 *(unsigned int *) loc = val; 214 else if (bits == 64) 215 *(unsigned long *) loc = val; 216 return 0; 217 } 218 219 static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab, 220 const char *strtab, struct module *me) 221 { 222 struct mod_arch_syminfo *info; 223 Elf_Addr loc, val; 224 int r_type, r_sym; 225 int rc = -ENOEXEC; 226 227 /* This is where to make the change */ 228 loc = base + rela->r_offset; 229 /* This is the symbol it is referring to. Note that all 230 undefined symbols have been resolved. */ 231 r_sym = ELF_R_SYM(rela->r_info); 232 r_type = ELF_R_TYPE(rela->r_info); 233 info = me->arch.syminfo + r_sym; 234 val = symtab[r_sym].st_value; 235 236 switch (r_type) { 237 case R_390_NONE: /* No relocation. */ 238 rc = 0; 239 break; 240 case R_390_8: /* Direct 8 bit. */ 241 case R_390_12: /* Direct 12 bit. */ 242 case R_390_16: /* Direct 16 bit. */ 243 case R_390_20: /* Direct 20 bit. */ 244 case R_390_32: /* Direct 32 bit. */ 245 case R_390_64: /* Direct 64 bit. */ 246 val += rela->r_addend; 247 if (r_type == R_390_8) 248 rc = apply_rela_bits(loc, val, 0, 8, 0); 249 else if (r_type == R_390_12) 250 rc = apply_rela_bits(loc, val, 0, 12, 0); 251 else if (r_type == R_390_16) 252 rc = apply_rela_bits(loc, val, 0, 16, 0); 253 else if (r_type == R_390_20) 254 rc = apply_rela_bits(loc, val, 1, 20, 0); 255 else if (r_type == R_390_32) 256 rc = apply_rela_bits(loc, val, 0, 32, 0); 257 else if (r_type == R_390_64) 258 rc = apply_rela_bits(loc, val, 0, 64, 0); 259 break; 260 case R_390_PC16: /* PC relative 16 bit. */ 261 case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */ 262 case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */ 263 case R_390_PC32: /* PC relative 32 bit. */ 264 case R_390_PC64: /* PC relative 64 bit. */ 265 val += rela->r_addend - loc; 266 if (r_type == R_390_PC16) 267 rc = apply_rela_bits(loc, val, 1, 16, 0); 268 else if (r_type == R_390_PC16DBL) 269 rc = apply_rela_bits(loc, val, 1, 16, 1); 270 else if (r_type == R_390_PC32DBL) 271 rc = apply_rela_bits(loc, val, 1, 32, 1); 272 else if (r_type == R_390_PC32) 273 rc = apply_rela_bits(loc, val, 1, 32, 0); 274 else if (r_type == R_390_PC64) 275 rc = apply_rela_bits(loc, val, 1, 64, 0); 276 break; 277 case R_390_GOT12: /* 12 bit GOT offset. */ 278 case R_390_GOT16: /* 16 bit GOT offset. */ 279 case R_390_GOT20: /* 20 bit GOT offset. */ 280 case R_390_GOT32: /* 32 bit GOT offset. */ 281 case R_390_GOT64: /* 64 bit GOT offset. */ 282 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */ 283 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */ 284 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */ 285 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */ 286 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */ 287 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */ 288 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */ 289 if (info->got_initialized == 0) { 290 Elf_Addr *gotent; 291 292 gotent = me->module_core + me->arch.got_offset + 293 info->got_offset; 294 *gotent = val; 295 info->got_initialized = 1; 296 } 297 val = info->got_offset + rela->r_addend; 298 if (r_type == R_390_GOT12 || 299 r_type == R_390_GOTPLT12) 300 rc = apply_rela_bits(loc, val, 0, 12, 0); 301 else if (r_type == R_390_GOT16 || 302 r_type == R_390_GOTPLT16) 303 rc = apply_rela_bits(loc, val, 0, 16, 0); 304 else if (r_type == R_390_GOT20 || 305 r_type == R_390_GOTPLT20) 306 rc = apply_rela_bits(loc, val, 1, 20, 0); 307 else if (r_type == R_390_GOT32 || 308 r_type == R_390_GOTPLT32) 309 rc = apply_rela_bits(loc, val, 0, 32, 0); 310 else if (r_type == R_390_GOT64 || 311 r_type == R_390_GOTPLT64) 312 rc = apply_rela_bits(loc, val, 0, 64, 0); 313 else if (r_type == R_390_GOTENT || 314 r_type == R_390_GOTPLTENT) { 315 val += (Elf_Addr) me->module_core - loc; 316 rc = apply_rela_bits(loc, val, 1, 32, 1); 317 } 318 break; 319 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */ 320 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */ 321 case R_390_PLT32: /* 32 bit PC relative PLT address. */ 322 case R_390_PLT64: /* 64 bit PC relative PLT address. */ 323 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */ 324 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */ 325 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */ 326 if (info->plt_initialized == 0) { 327 unsigned int *ip; 328 ip = me->module_core + me->arch.plt_offset + 329 info->plt_offset; 330 #ifndef CONFIG_64BIT 331 ip[0] = 0x0d105810; /* basr 1,0; l 1,6(1); br 1 */ 332 ip[1] = 0x100607f1; 333 ip[2] = val; 334 #else /* CONFIG_64BIT */ 335 ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */ 336 ip[1] = 0x100a0004; 337 ip[2] = 0x07f10000; 338 ip[3] = (unsigned int) (val >> 32); 339 ip[4] = (unsigned int) val; 340 #endif /* CONFIG_64BIT */ 341 info->plt_initialized = 1; 342 } 343 if (r_type == R_390_PLTOFF16 || 344 r_type == R_390_PLTOFF32 || 345 r_type == R_390_PLTOFF64) 346 val = me->arch.plt_offset - me->arch.got_offset + 347 info->plt_offset + rela->r_addend; 348 else { 349 if (!((r_type == R_390_PLT16DBL && 350 val - loc + 0xffffUL < 0x1ffffeUL) || 351 (r_type == R_390_PLT32DBL && 352 val - loc + 0xffffffffULL < 0x1fffffffeULL))) 353 val = (Elf_Addr) me->module_core + 354 me->arch.plt_offset + 355 info->plt_offset; 356 val += rela->r_addend - loc; 357 } 358 if (r_type == R_390_PLT16DBL) 359 rc = apply_rela_bits(loc, val, 1, 16, 1); 360 else if (r_type == R_390_PLTOFF16) 361 rc = apply_rela_bits(loc, val, 0, 16, 0); 362 else if (r_type == R_390_PLT32DBL) 363 rc = apply_rela_bits(loc, val, 1, 32, 1); 364 else if (r_type == R_390_PLT32 || 365 r_type == R_390_PLTOFF32) 366 rc = apply_rela_bits(loc, val, 0, 32, 0); 367 else if (r_type == R_390_PLT64 || 368 r_type == R_390_PLTOFF64) 369 rc = apply_rela_bits(loc, val, 0, 64, 0); 370 break; 371 case R_390_GOTOFF16: /* 16 bit offset to GOT. */ 372 case R_390_GOTOFF32: /* 32 bit offset to GOT. */ 373 case R_390_GOTOFF64: /* 64 bit offset to GOT. */ 374 val = val + rela->r_addend - 375 ((Elf_Addr) me->module_core + me->arch.got_offset); 376 if (r_type == R_390_GOTOFF16) 377 rc = apply_rela_bits(loc, val, 0, 16, 0); 378 else if (r_type == R_390_GOTOFF32) 379 rc = apply_rela_bits(loc, val, 0, 32, 0); 380 else if (r_type == R_390_GOTOFF64) 381 rc = apply_rela_bits(loc, val, 0, 64, 0); 382 break; 383 case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */ 384 case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */ 385 val = (Elf_Addr) me->module_core + me->arch.got_offset + 386 rela->r_addend - loc; 387 if (r_type == R_390_GOTPC) 388 rc = apply_rela_bits(loc, val, 1, 32, 0); 389 else if (r_type == R_390_GOTPCDBL) 390 rc = apply_rela_bits(loc, val, 1, 32, 1); 391 break; 392 case R_390_COPY: 393 case R_390_GLOB_DAT: /* Create GOT entry. */ 394 case R_390_JMP_SLOT: /* Create PLT entry. */ 395 case R_390_RELATIVE: /* Adjust by program base. */ 396 /* Only needed if we want to support loading of 397 modules linked with -shared. */ 398 return -ENOEXEC; 399 default: 400 printk(KERN_ERR "module %s: unknown relocation: %u\n", 401 me->name, r_type); 402 return -ENOEXEC; 403 } 404 if (rc) { 405 printk(KERN_ERR "module %s: relocation error for symbol %s " 406 "(r_type %i, value 0x%lx)\n", 407 me->name, strtab + symtab[r_sym].st_name, 408 r_type, (unsigned long) val); 409 return rc; 410 } 411 return 0; 412 } 413 414 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 415 unsigned int symindex, unsigned int relsec, 416 struct module *me) 417 { 418 Elf_Addr base; 419 Elf_Sym *symtab; 420 Elf_Rela *rela; 421 unsigned long i, n; 422 int rc; 423 424 DEBUGP("Applying relocate section %u to %u\n", 425 relsec, sechdrs[relsec].sh_info); 426 base = sechdrs[sechdrs[relsec].sh_info].sh_addr; 427 symtab = (Elf_Sym *) sechdrs[symindex].sh_addr; 428 rela = (Elf_Rela *) sechdrs[relsec].sh_addr; 429 n = sechdrs[relsec].sh_size / sizeof(Elf_Rela); 430 431 for (i = 0; i < n; i++, rela++) { 432 rc = apply_rela(rela, base, symtab, strtab, me); 433 if (rc) 434 return rc; 435 } 436 return 0; 437 } 438 439 int module_finalize(const Elf_Ehdr *hdr, 440 const Elf_Shdr *sechdrs, 441 struct module *me) 442 { 443 vfree(me->arch.syminfo); 444 me->arch.syminfo = NULL; 445 return 0; 446 } 447