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