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_EXEC, 49 0, NUMA_NO_NODE, 50 __builtin_return_address(0)); 51 } 52 53 void module_arch_freeing_init(struct module *mod) 54 { 55 if (is_livepatch_module(mod) && 56 mod->state == MODULE_STATE_LIVE) 57 return; 58 59 vfree(mod->arch.syminfo); 60 mod->arch.syminfo = NULL; 61 } 62 63 static void check_rela(Elf_Rela *rela, struct module *me) 64 { 65 struct mod_arch_syminfo *info; 66 67 info = me->arch.syminfo + ELF_R_SYM (rela->r_info); 68 switch (ELF_R_TYPE (rela->r_info)) { 69 case R_390_GOT12: /* 12 bit GOT offset. */ 70 case R_390_GOT16: /* 16 bit GOT offset. */ 71 case R_390_GOT20: /* 20 bit GOT offset. */ 72 case R_390_GOT32: /* 32 bit GOT offset. */ 73 case R_390_GOT64: /* 64 bit GOT offset. */ 74 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */ 75 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */ 76 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */ 77 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */ 78 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */ 79 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */ 80 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */ 81 if (info->got_offset == -1UL) { 82 info->got_offset = me->arch.got_size; 83 me->arch.got_size += sizeof(void*); 84 } 85 break; 86 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */ 87 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */ 88 case R_390_PLT32: /* 32 bit PC relative PLT address. */ 89 case R_390_PLT64: /* 64 bit PC relative PLT address. */ 90 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */ 91 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */ 92 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */ 93 if (info->plt_offset == -1UL) { 94 info->plt_offset = me->arch.plt_size; 95 me->arch.plt_size += PLT_ENTRY_SIZE; 96 } 97 break; 98 case R_390_COPY: 99 case R_390_GLOB_DAT: 100 case R_390_JMP_SLOT: 101 case R_390_RELATIVE: 102 /* Only needed if we want to support loading of 103 modules linked with -shared. */ 104 break; 105 } 106 } 107 108 /* 109 * Account for GOT and PLT relocations. We can't add sections for 110 * got and plt but we can increase the core module size. 111 */ 112 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 113 char *secstrings, struct module *me) 114 { 115 Elf_Shdr *symtab; 116 Elf_Sym *symbols; 117 Elf_Rela *rela; 118 char *strings; 119 int nrela, i, j; 120 121 /* Find symbol table and string table. */ 122 symtab = NULL; 123 for (i = 0; i < hdr->e_shnum; i++) 124 switch (sechdrs[i].sh_type) { 125 case SHT_SYMTAB: 126 symtab = sechdrs + i; 127 break; 128 } 129 if (!symtab) { 130 printk(KERN_ERR "module %s: no symbol table\n", me->name); 131 return -ENOEXEC; 132 } 133 134 /* Allocate one syminfo structure per symbol. */ 135 me->arch.nsyms = symtab->sh_size / sizeof(Elf_Sym); 136 me->arch.syminfo = vmalloc(me->arch.nsyms * 137 sizeof(struct mod_arch_syminfo)); 138 if (!me->arch.syminfo) 139 return -ENOMEM; 140 symbols = (void *) hdr + symtab->sh_offset; 141 strings = (void *) hdr + sechdrs[symtab->sh_link].sh_offset; 142 for (i = 0; i < me->arch.nsyms; i++) { 143 if (symbols[i].st_shndx == SHN_UNDEF && 144 strcmp(strings + symbols[i].st_name, 145 "_GLOBAL_OFFSET_TABLE_") == 0) 146 /* "Define" it as absolute. */ 147 symbols[i].st_shndx = SHN_ABS; 148 me->arch.syminfo[i].got_offset = -1UL; 149 me->arch.syminfo[i].plt_offset = -1UL; 150 me->arch.syminfo[i].got_initialized = 0; 151 me->arch.syminfo[i].plt_initialized = 0; 152 } 153 154 /* Search for got/plt relocations. */ 155 me->arch.got_size = me->arch.plt_size = 0; 156 for (i = 0; i < hdr->e_shnum; i++) { 157 if (sechdrs[i].sh_type != SHT_RELA) 158 continue; 159 nrela = sechdrs[i].sh_size / sizeof(Elf_Rela); 160 rela = (void *) hdr + sechdrs[i].sh_offset; 161 for (j = 0; j < nrela; j++) 162 check_rela(rela + j, me); 163 } 164 165 /* Increase core size by size of got & plt and set start 166 offsets for got and plt. */ 167 me->core_layout.size = ALIGN(me->core_layout.size, 4); 168 me->arch.got_offset = me->core_layout.size; 169 me->core_layout.size += me->arch.got_size; 170 me->arch.plt_offset = me->core_layout.size; 171 me->core_layout.size += me->arch.plt_size; 172 return 0; 173 } 174 175 static int apply_rela_bits(Elf_Addr loc, Elf_Addr val, 176 int sign, int bits, int shift) 177 { 178 unsigned long umax; 179 long min, max; 180 181 if (val & ((1UL << shift) - 1)) 182 return -ENOEXEC; 183 if (sign) { 184 val = (Elf_Addr)(((long) val) >> shift); 185 min = -(1L << (bits - 1)); 186 max = (1L << (bits - 1)) - 1; 187 if ((long) val < min || (long) val > max) 188 return -ENOEXEC; 189 } else { 190 val >>= shift; 191 umax = ((1UL << (bits - 1)) << 1) - 1; 192 if ((unsigned long) val > umax) 193 return -ENOEXEC; 194 } 195 196 if (bits == 8) 197 *(unsigned char *) loc = val; 198 else if (bits == 12) 199 *(unsigned short *) loc = (val & 0xfff) | 200 (*(unsigned short *) loc & 0xf000); 201 else if (bits == 16) 202 *(unsigned short *) loc = val; 203 else if (bits == 20) 204 *(unsigned int *) loc = (val & 0xfff) << 16 | 205 (val & 0xff000) >> 4 | 206 (*(unsigned int *) loc & 0xf00000ff); 207 else if (bits == 32) 208 *(unsigned int *) loc = val; 209 else if (bits == 64) 210 *(unsigned long *) loc = val; 211 return 0; 212 } 213 214 static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab, 215 const char *strtab, struct module *me) 216 { 217 struct mod_arch_syminfo *info; 218 Elf_Addr loc, val; 219 int r_type, r_sym; 220 int rc = -ENOEXEC; 221 222 /* This is where to make the change */ 223 loc = base + rela->r_offset; 224 /* This is the symbol it is referring to. Note that all 225 undefined symbols have been resolved. */ 226 r_sym = ELF_R_SYM(rela->r_info); 227 r_type = ELF_R_TYPE(rela->r_info); 228 info = me->arch.syminfo + r_sym; 229 val = symtab[r_sym].st_value; 230 231 switch (r_type) { 232 case R_390_NONE: /* No relocation. */ 233 rc = 0; 234 break; 235 case R_390_8: /* Direct 8 bit. */ 236 case R_390_12: /* Direct 12 bit. */ 237 case R_390_16: /* Direct 16 bit. */ 238 case R_390_20: /* Direct 20 bit. */ 239 case R_390_32: /* Direct 32 bit. */ 240 case R_390_64: /* Direct 64 bit. */ 241 val += rela->r_addend; 242 if (r_type == R_390_8) 243 rc = apply_rela_bits(loc, val, 0, 8, 0); 244 else if (r_type == R_390_12) 245 rc = apply_rela_bits(loc, val, 0, 12, 0); 246 else if (r_type == R_390_16) 247 rc = apply_rela_bits(loc, val, 0, 16, 0); 248 else if (r_type == R_390_20) 249 rc = apply_rela_bits(loc, val, 1, 20, 0); 250 else if (r_type == R_390_32) 251 rc = apply_rela_bits(loc, val, 0, 32, 0); 252 else if (r_type == R_390_64) 253 rc = apply_rela_bits(loc, val, 0, 64, 0); 254 break; 255 case R_390_PC16: /* PC relative 16 bit. */ 256 case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */ 257 case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */ 258 case R_390_PC32: /* PC relative 32 bit. */ 259 case R_390_PC64: /* PC relative 64 bit. */ 260 val += rela->r_addend - loc; 261 if (r_type == R_390_PC16) 262 rc = apply_rela_bits(loc, val, 1, 16, 0); 263 else if (r_type == R_390_PC16DBL) 264 rc = apply_rela_bits(loc, val, 1, 16, 1); 265 else if (r_type == R_390_PC32DBL) 266 rc = apply_rela_bits(loc, val, 1, 32, 1); 267 else if (r_type == R_390_PC32) 268 rc = apply_rela_bits(loc, val, 1, 32, 0); 269 else if (r_type == R_390_PC64) 270 rc = apply_rela_bits(loc, val, 1, 64, 0); 271 break; 272 case R_390_GOT12: /* 12 bit GOT offset. */ 273 case R_390_GOT16: /* 16 bit GOT offset. */ 274 case R_390_GOT20: /* 20 bit GOT offset. */ 275 case R_390_GOT32: /* 32 bit GOT offset. */ 276 case R_390_GOT64: /* 64 bit GOT offset. */ 277 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */ 278 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */ 279 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */ 280 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */ 281 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */ 282 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */ 283 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */ 284 if (info->got_initialized == 0) { 285 Elf_Addr *gotent; 286 287 gotent = me->core_layout.base + me->arch.got_offset + 288 info->got_offset; 289 *gotent = val; 290 info->got_initialized = 1; 291 } 292 val = info->got_offset + rela->r_addend; 293 if (r_type == R_390_GOT12 || 294 r_type == R_390_GOTPLT12) 295 rc = apply_rela_bits(loc, val, 0, 12, 0); 296 else if (r_type == R_390_GOT16 || 297 r_type == R_390_GOTPLT16) 298 rc = apply_rela_bits(loc, val, 0, 16, 0); 299 else if (r_type == R_390_GOT20 || 300 r_type == R_390_GOTPLT20) 301 rc = apply_rela_bits(loc, val, 1, 20, 0); 302 else if (r_type == R_390_GOT32 || 303 r_type == R_390_GOTPLT32) 304 rc = apply_rela_bits(loc, val, 0, 32, 0); 305 else if (r_type == R_390_GOT64 || 306 r_type == R_390_GOTPLT64) 307 rc = apply_rela_bits(loc, val, 0, 64, 0); 308 else if (r_type == R_390_GOTENT || 309 r_type == R_390_GOTPLTENT) { 310 val += (Elf_Addr) me->core_layout.base - loc; 311 rc = apply_rela_bits(loc, val, 1, 32, 1); 312 } 313 break; 314 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */ 315 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */ 316 case R_390_PLT32: /* 32 bit PC relative PLT address. */ 317 case R_390_PLT64: /* 64 bit PC relative PLT address. */ 318 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */ 319 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */ 320 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */ 321 if (info->plt_initialized == 0) { 322 unsigned int *ip; 323 ip = me->core_layout.base + me->arch.plt_offset + 324 info->plt_offset; 325 ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */ 326 ip[1] = 0x100a0004; 327 ip[2] = 0x07f10000; 328 ip[3] = (unsigned int) (val >> 32); 329 ip[4] = (unsigned int) val; 330 info->plt_initialized = 1; 331 } 332 if (r_type == R_390_PLTOFF16 || 333 r_type == R_390_PLTOFF32 || 334 r_type == R_390_PLTOFF64) 335 val = me->arch.plt_offset - me->arch.got_offset + 336 info->plt_offset + rela->r_addend; 337 else { 338 if (!((r_type == R_390_PLT16DBL && 339 val - loc + 0xffffUL < 0x1ffffeUL) || 340 (r_type == R_390_PLT32DBL && 341 val - loc + 0xffffffffULL < 0x1fffffffeULL))) 342 val = (Elf_Addr) me->core_layout.base + 343 me->arch.plt_offset + 344 info->plt_offset; 345 val += rela->r_addend - loc; 346 } 347 if (r_type == R_390_PLT16DBL) 348 rc = apply_rela_bits(loc, val, 1, 16, 1); 349 else if (r_type == R_390_PLTOFF16) 350 rc = apply_rela_bits(loc, val, 0, 16, 0); 351 else if (r_type == R_390_PLT32DBL) 352 rc = apply_rela_bits(loc, val, 1, 32, 1); 353 else if (r_type == R_390_PLT32 || 354 r_type == R_390_PLTOFF32) 355 rc = apply_rela_bits(loc, val, 0, 32, 0); 356 else if (r_type == R_390_PLT64 || 357 r_type == R_390_PLTOFF64) 358 rc = apply_rela_bits(loc, val, 0, 64, 0); 359 break; 360 case R_390_GOTOFF16: /* 16 bit offset to GOT. */ 361 case R_390_GOTOFF32: /* 32 bit offset to GOT. */ 362 case R_390_GOTOFF64: /* 64 bit offset to GOT. */ 363 val = val + rela->r_addend - 364 ((Elf_Addr) me->core_layout.base + me->arch.got_offset); 365 if (r_type == R_390_GOTOFF16) 366 rc = apply_rela_bits(loc, val, 0, 16, 0); 367 else if (r_type == R_390_GOTOFF32) 368 rc = apply_rela_bits(loc, val, 0, 32, 0); 369 else if (r_type == R_390_GOTOFF64) 370 rc = apply_rela_bits(loc, val, 0, 64, 0); 371 break; 372 case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */ 373 case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */ 374 val = (Elf_Addr) me->core_layout.base + me->arch.got_offset + 375 rela->r_addend - loc; 376 if (r_type == R_390_GOTPC) 377 rc = apply_rela_bits(loc, val, 1, 32, 0); 378 else if (r_type == R_390_GOTPCDBL) 379 rc = apply_rela_bits(loc, val, 1, 32, 1); 380 break; 381 case R_390_COPY: 382 case R_390_GLOB_DAT: /* Create GOT entry. */ 383 case R_390_JMP_SLOT: /* Create PLT entry. */ 384 case R_390_RELATIVE: /* Adjust by program base. */ 385 /* Only needed if we want to support loading of 386 modules linked with -shared. */ 387 return -ENOEXEC; 388 default: 389 printk(KERN_ERR "module %s: unknown relocation: %u\n", 390 me->name, r_type); 391 return -ENOEXEC; 392 } 393 if (rc) { 394 printk(KERN_ERR "module %s: relocation error for symbol %s " 395 "(r_type %i, value 0x%lx)\n", 396 me->name, strtab + symtab[r_sym].st_name, 397 r_type, (unsigned long) val); 398 return rc; 399 } 400 return 0; 401 } 402 403 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 404 unsigned int symindex, unsigned int relsec, 405 struct module *me) 406 { 407 Elf_Addr base; 408 Elf_Sym *symtab; 409 Elf_Rela *rela; 410 unsigned long i, n; 411 int rc; 412 413 DEBUGP("Applying relocate section %u to %u\n", 414 relsec, sechdrs[relsec].sh_info); 415 base = sechdrs[sechdrs[relsec].sh_info].sh_addr; 416 symtab = (Elf_Sym *) sechdrs[symindex].sh_addr; 417 rela = (Elf_Rela *) sechdrs[relsec].sh_addr; 418 n = sechdrs[relsec].sh_size / sizeof(Elf_Rela); 419 420 for (i = 0; i < n; i++, rela++) { 421 rc = apply_rela(rela, base, symtab, strtab, me); 422 if (rc) 423 return rc; 424 } 425 return 0; 426 } 427 428 int module_finalize(const Elf_Ehdr *hdr, 429 const Elf_Shdr *sechdrs, 430 struct module *me) 431 { 432 jump_label_apply_nops(me); 433 return 0; 434 } 435