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