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