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