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 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 void *module_alloc(unsigned long size) 48 { 49 if (size == 0) 50 return NULL; 51 return vmalloc(size); 52 } 53 54 /* Free memory returned from module_alloc */ 55 void module_free(struct module *mod, void *module_region) 56 { 57 vfree(module_region); 58 /* FIXME: If module_region == mod->init_region, trim exception 59 table entries. */ 60 } 61 62 static void 63 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 113 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 int 177 apply_relocate(Elf_Shdr *sechdrs, const char *strtab, unsigned int symindex, 178 unsigned int relsec, struct module *me) 179 { 180 printk(KERN_ERR "module %s: RELOCATION unsupported\n", 181 me->name); 182 return -ENOEXEC; 183 } 184 185 static int 186 apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab, 187 struct module *me) 188 { 189 struct mod_arch_syminfo *info; 190 Elf_Addr loc, val; 191 int r_type, r_sym; 192 193 /* This is where to make the change */ 194 loc = base + rela->r_offset; 195 /* This is the symbol it is referring to. Note that all 196 undefined symbols have been resolved. */ 197 r_sym = ELF_R_SYM(rela->r_info); 198 r_type = ELF_R_TYPE(rela->r_info); 199 info = me->arch.syminfo + r_sym; 200 val = symtab[r_sym].st_value; 201 202 switch (r_type) { 203 case R_390_8: /* Direct 8 bit. */ 204 case R_390_12: /* Direct 12 bit. */ 205 case R_390_16: /* Direct 16 bit. */ 206 case R_390_20: /* Direct 20 bit. */ 207 case R_390_32: /* Direct 32 bit. */ 208 case R_390_64: /* Direct 64 bit. */ 209 val += rela->r_addend; 210 if (r_type == R_390_8) 211 *(unsigned char *) loc = val; 212 else if (r_type == R_390_12) 213 *(unsigned short *) loc = (val & 0xfff) | 214 (*(unsigned short *) loc & 0xf000); 215 else if (r_type == R_390_16) 216 *(unsigned short *) loc = val; 217 else if (r_type == R_390_20) 218 *(unsigned int *) loc = 219 (*(unsigned int *) loc & 0xf00000ff) | 220 (val & 0xfff) << 16 | (val & 0xff000) >> 4; 221 else if (r_type == R_390_32) 222 *(unsigned int *) loc = val; 223 else if (r_type == R_390_64) 224 *(unsigned long *) loc = val; 225 break; 226 case R_390_PC16: /* PC relative 16 bit. */ 227 case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */ 228 case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */ 229 case R_390_PC32: /* PC relative 32 bit. */ 230 case R_390_PC64: /* PC relative 64 bit. */ 231 val += rela->r_addend - loc; 232 if (r_type == R_390_PC16) 233 *(unsigned short *) loc = val; 234 else if (r_type == R_390_PC16DBL) 235 *(unsigned short *) loc = val >> 1; 236 else if (r_type == R_390_PC32DBL) 237 *(unsigned int *) loc = val >> 1; 238 else if (r_type == R_390_PC32) 239 *(unsigned int *) loc = val; 240 else if (r_type == R_390_PC64) 241 *(unsigned long *) loc = val; 242 break; 243 case R_390_GOT12: /* 12 bit GOT offset. */ 244 case R_390_GOT16: /* 16 bit GOT offset. */ 245 case R_390_GOT20: /* 20 bit GOT offset. */ 246 case R_390_GOT32: /* 32 bit GOT offset. */ 247 case R_390_GOT64: /* 64 bit GOT offset. */ 248 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */ 249 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */ 250 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */ 251 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */ 252 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */ 253 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */ 254 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */ 255 if (info->got_initialized == 0) { 256 Elf_Addr *gotent; 257 258 gotent = me->module_core + me->arch.got_offset + 259 info->got_offset; 260 *gotent = val; 261 info->got_initialized = 1; 262 } 263 val = info->got_offset + rela->r_addend; 264 if (r_type == R_390_GOT12 || 265 r_type == R_390_GOTPLT12) 266 *(unsigned short *) loc = (val & 0xfff) | 267 (*(unsigned short *) loc & 0xf000); 268 else if (r_type == R_390_GOT16 || 269 r_type == R_390_GOTPLT16) 270 *(unsigned short *) loc = val; 271 else if (r_type == R_390_GOT20 || 272 r_type == R_390_GOTPLT20) 273 *(unsigned int *) loc = 274 (*(unsigned int *) loc & 0xf00000ff) | 275 (val & 0xfff) << 16 | (val & 0xff000) >> 4; 276 else if (r_type == R_390_GOT32 || 277 r_type == R_390_GOTPLT32) 278 *(unsigned int *) loc = val; 279 else if (r_type == R_390_GOTENT || 280 r_type == R_390_GOTPLTENT) 281 *(unsigned int *) loc = 282 (val + (Elf_Addr) me->module_core - loc) >> 1; 283 else if (r_type == R_390_GOT64 || 284 r_type == R_390_GOTPLT64) 285 *(unsigned long *) loc = val; 286 break; 287 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */ 288 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */ 289 case R_390_PLT32: /* 32 bit PC relative PLT address. */ 290 case R_390_PLT64: /* 64 bit PC relative PLT address. */ 291 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */ 292 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */ 293 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */ 294 if (info->plt_initialized == 0) { 295 unsigned int *ip; 296 ip = me->module_core + me->arch.plt_offset + 297 info->plt_offset; 298 #ifndef CONFIG_64BIT 299 ip[0] = 0x0d105810; /* basr 1,0; l 1,6(1); br 1 */ 300 ip[1] = 0x100607f1; 301 ip[2] = val; 302 #else /* CONFIG_64BIT */ 303 ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */ 304 ip[1] = 0x100a0004; 305 ip[2] = 0x07f10000; 306 ip[3] = (unsigned int) (val >> 32); 307 ip[4] = (unsigned int) val; 308 #endif /* CONFIG_64BIT */ 309 info->plt_initialized = 1; 310 } 311 if (r_type == R_390_PLTOFF16 || 312 r_type == R_390_PLTOFF32 313 || r_type == R_390_PLTOFF64 314 ) 315 val = me->arch.plt_offset - me->arch.got_offset + 316 info->plt_offset + rela->r_addend; 317 else 318 val = (Elf_Addr) me->module_core + 319 me->arch.plt_offset + info->plt_offset + 320 rela->r_addend - loc; 321 if (r_type == R_390_PLT16DBL) 322 *(unsigned short *) loc = val >> 1; 323 else if (r_type == R_390_PLTOFF16) 324 *(unsigned short *) loc = val; 325 else if (r_type == R_390_PLT32DBL) 326 *(unsigned int *) loc = val >> 1; 327 else if (r_type == R_390_PLT32 || 328 r_type == R_390_PLTOFF32) 329 *(unsigned int *) loc = val; 330 else if (r_type == R_390_PLT64 || 331 r_type == R_390_PLTOFF64) 332 *(unsigned long *) loc = val; 333 break; 334 case R_390_GOTOFF16: /* 16 bit offset to GOT. */ 335 case R_390_GOTOFF32: /* 32 bit offset to GOT. */ 336 case R_390_GOTOFF64: /* 64 bit offset to GOT. */ 337 val = val + rela->r_addend - 338 ((Elf_Addr) me->module_core + me->arch.got_offset); 339 if (r_type == R_390_GOTOFF16) 340 *(unsigned short *) loc = val; 341 else if (r_type == R_390_GOTOFF32) 342 *(unsigned int *) loc = val; 343 else if (r_type == R_390_GOTOFF64) 344 *(unsigned long *) loc = val; 345 break; 346 case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */ 347 case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */ 348 val = (Elf_Addr) me->module_core + me->arch.got_offset + 349 rela->r_addend - loc; 350 if (r_type == R_390_GOTPC) 351 *(unsigned int *) loc = val; 352 else if (r_type == R_390_GOTPCDBL) 353 *(unsigned int *) loc = val >> 1; 354 break; 355 case R_390_COPY: 356 case R_390_GLOB_DAT: /* Create GOT entry. */ 357 case R_390_JMP_SLOT: /* Create PLT entry. */ 358 case R_390_RELATIVE: /* Adjust by program base. */ 359 /* Only needed if we want to support loading of 360 modules linked with -shared. */ 361 break; 362 default: 363 printk(KERN_ERR "module %s: Unknown relocation: %u\n", 364 me->name, r_type); 365 return -ENOEXEC; 366 } 367 return 0; 368 } 369 370 int 371 apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 372 unsigned int symindex, unsigned int relsec, 373 struct module *me) 374 { 375 Elf_Addr base; 376 Elf_Sym *symtab; 377 Elf_Rela *rela; 378 unsigned long i, n; 379 int rc; 380 381 DEBUGP("Applying relocate section %u to %u\n", 382 relsec, sechdrs[relsec].sh_info); 383 base = sechdrs[sechdrs[relsec].sh_info].sh_addr; 384 symtab = (Elf_Sym *) sechdrs[symindex].sh_addr; 385 rela = (Elf_Rela *) sechdrs[relsec].sh_addr; 386 n = sechdrs[relsec].sh_size / sizeof(Elf_Rela); 387 388 for (i = 0; i < n; i++, rela++) { 389 rc = apply_rela(rela, base, symtab, me); 390 if (rc) 391 return rc; 392 } 393 return 0; 394 } 395 396 int module_finalize(const Elf_Ehdr *hdr, 397 const Elf_Shdr *sechdrs, 398 struct module *me) 399 { 400 vfree(me->arch.syminfo); 401 return 0; 402 } 403 404 void module_arch_cleanup(struct module *mod) 405 { 406 } 407