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#define DEBUGP(fmt , ...) 37 38#ifndef CONFIG_64BIT 39#define PLT_ENTRY_SIZE 12 40#else /* CONFIG_64BIT */ 41#define PLT_ENTRY_SIZE 20 42#endif /* CONFIG_64BIT */ 43 44void *module_alloc(unsigned long size) 45{ 46 if (size == 0) 47 return NULL; 48 return vmalloc(size); 49} 50 51/* Free memory returned from module_alloc */ 52void module_free(struct module *mod, void *module_region) 53{ 54 if (mod) { 55 vfree(mod->arch.syminfo); 56 mod->arch.syminfo = NULL; 57 } 58 vfree(module_region); 59} 60 61static void 62check_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 */ 111int 112module_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_size = ALIGN(me->core_size, 4); 168 me->arch.got_offset = me->core_size; 169 me->core_size += me->arch.got_size; 170 me->arch.plt_offset = me->core_size; 171 me->core_size += me->arch.plt_size; 172 return 0; 173} 174 175int 176apply_relocate(Elf_Shdr *sechdrs, const char *strtab, unsigned int symindex, 177 unsigned int relsec, struct module *me) 178{ 179 printk(KERN_ERR "module %s: RELOCATION unsupported\n", 180 me->name); 181 return -ENOEXEC; 182} 183 184static int 185apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab, 186 struct module *me) 187{ 188 struct mod_arch_syminfo *info; 189 Elf_Addr loc, val; 190 int r_type, r_sym; 191 192 /* This is where to make the change */ 193 loc = base + rela->r_offset; 194 /* This is the symbol it is referring to. Note that all 195 undefined symbols have been resolved. */ 196 r_sym = ELF_R_SYM(rela->r_info); 197 r_type = ELF_R_TYPE(rela->r_info); 198 info = me->arch.syminfo + r_sym; 199 val = symtab[r_sym].st_value; 200 201 switch (r_type) { 202 case R_390_8: /* Direct 8 bit. */ 203 case R_390_12: /* Direct 12 bit. */ 204 case R_390_16: /* Direct 16 bit. */ 205 case R_390_20: /* Direct 20 bit. */ 206 case R_390_32: /* Direct 32 bit. */ 207 case R_390_64: /* Direct 64 bit. */ 208 val += rela->r_addend; 209 if (r_type == R_390_8) 210 *(unsigned char *) loc = val; 211 else if (r_type == R_390_12) 212 *(unsigned short *) loc = (val & 0xfff) | 213 (*(unsigned short *) loc & 0xf000); 214 else if (r_type == R_390_16) 215 *(unsigned short *) loc = val; 216 else if (r_type == R_390_20) 217 *(unsigned int *) loc = 218 (*(unsigned int *) loc & 0xf00000ff) | 219 (val & 0xfff) << 16 | (val & 0xff000) >> 4; 220 else if (r_type == R_390_32) 221 *(unsigned int *) loc = val; 222 else if (r_type == R_390_64) 223 *(unsigned long *) loc = val; 224 break; 225 case R_390_PC16: /* PC relative 16 bit. */ 226 case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */ 227 case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */ 228 case R_390_PC32: /* PC relative 32 bit. */ 229 case R_390_PC64: /* PC relative 64 bit. */ 230 val += rela->r_addend - loc; 231 if (r_type == R_390_PC16) 232 *(unsigned short *) loc = val; 233 else if (r_type == R_390_PC16DBL) 234 *(unsigned short *) loc = val >> 1; 235 else if (r_type == R_390_PC32DBL) 236 *(unsigned int *) loc = val >> 1; 237 else if (r_type == R_390_PC32) 238 *(unsigned int *) loc = val; 239 else if (r_type == R_390_PC64) 240 *(unsigned long *) loc = val; 241 break; 242 case R_390_GOT12: /* 12 bit GOT offset. */ 243 case R_390_GOT16: /* 16 bit GOT offset. */ 244 case R_390_GOT20: /* 20 bit GOT offset. */ 245 case R_390_GOT32: /* 32 bit GOT offset. */ 246 case R_390_GOT64: /* 64 bit GOT offset. */ 247 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */ 248 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */ 249 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */ 250 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */ 251 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */ 252 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */ 253 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */ 254 if (info->got_initialized == 0) { 255 Elf_Addr *gotent; 256 257 gotent = me->module_core + me->arch.got_offset + 258 info->got_offset; 259 *gotent = val; 260 info->got_initialized = 1; 261 } 262 val = info->got_offset + rela->r_addend; 263 if (r_type == R_390_GOT12 || 264 r_type == R_390_GOTPLT12) 265 *(unsigned short *) loc = (val & 0xfff) | 266 (*(unsigned short *) loc & 0xf000); 267 else if (r_type == R_390_GOT16 || 268 r_type == R_390_GOTPLT16) 269 *(unsigned short *) loc = val; 270 else if (r_type == R_390_GOT20 || 271 r_type == R_390_GOTPLT20) 272 *(unsigned int *) loc = 273 (*(unsigned int *) loc & 0xf00000ff) | 274 (val & 0xfff) << 16 | (val & 0xff000) >> 4; 275 else if (r_type == R_390_GOT32 || 276 r_type == R_390_GOTPLT32) 277 *(unsigned int *) loc = val; 278 else if (r_type == R_390_GOTENT || 279 r_type == R_390_GOTPLTENT) 280 *(unsigned int *) loc = 281 (val + (Elf_Addr) me->module_core - loc) >> 1; 282 else if (r_type == R_390_GOT64 || 283 r_type == R_390_GOTPLT64) 284 *(unsigned long *) loc = val; 285 break; 286 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */ 287 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */ 288 case R_390_PLT32: /* 32 bit PC relative PLT address. */ 289 case R_390_PLT64: /* 64 bit PC relative PLT address. */ 290 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */ 291 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */ 292 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */ 293 if (info->plt_initialized == 0) { 294 unsigned int *ip; 295 ip = me->module_core + me->arch.plt_offset + 296 info->plt_offset; 297#ifndef CONFIG_64BIT 298 ip[0] = 0x0d105810; /* basr 1,0; l 1,6(1); br 1 */ 299 ip[1] = 0x100607f1; 300 ip[2] = val; 301#else /* CONFIG_64BIT */ 302 ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */ 303 ip[1] = 0x100a0004; 304 ip[2] = 0x07f10000; 305 ip[3] = (unsigned int) (val >> 32); 306 ip[4] = (unsigned int) val; 307#endif /* CONFIG_64BIT */ 308 info->plt_initialized = 1; 309 } 310 if (r_type == R_390_PLTOFF16 || 311 r_type == R_390_PLTOFF32 || 312 r_type == R_390_PLTOFF64) 313 val = me->arch.plt_offset - me->arch.got_offset + 314 info->plt_offset + rela->r_addend; 315 else { 316 if (!((r_type == R_390_PLT16DBL && 317 val - loc + 0xffffUL < 0x1ffffeUL) || 318 (r_type == R_390_PLT32DBL && 319 val - loc + 0xffffffffULL < 0x1fffffffeULL))) 320 val = (Elf_Addr) me->module_core + 321 me->arch.plt_offset + 322 info->plt_offset; 323 val += rela->r_addend - loc; 324 } 325 if (r_type == R_390_PLT16DBL) 326 *(unsigned short *) loc = val >> 1; 327 else if (r_type == R_390_PLTOFF16) 328 *(unsigned short *) loc = val; 329 else if (r_type == R_390_PLT32DBL) 330 *(unsigned int *) loc = val >> 1; 331 else if (r_type == R_390_PLT32 || 332 r_type == R_390_PLTOFF32) 333 *(unsigned int *) loc = val; 334 else if (r_type == R_390_PLT64 || 335 r_type == R_390_PLTOFF64) 336 *(unsigned long *) loc = val; 337 break; 338 case R_390_GOTOFF16: /* 16 bit offset to GOT. */ 339 case R_390_GOTOFF32: /* 32 bit offset to GOT. */ 340 case R_390_GOTOFF64: /* 64 bit offset to GOT. */ 341 val = val + rela->r_addend - 342 ((Elf_Addr) me->module_core + me->arch.got_offset); 343 if (r_type == R_390_GOTOFF16) 344 *(unsigned short *) loc = val; 345 else if (r_type == R_390_GOTOFF32) 346 *(unsigned int *) loc = val; 347 else if (r_type == R_390_GOTOFF64) 348 *(unsigned long *) loc = val; 349 break; 350 case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */ 351 case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */ 352 val = (Elf_Addr) me->module_core + me->arch.got_offset + 353 rela->r_addend - loc; 354 if (r_type == R_390_GOTPC) 355 *(unsigned int *) loc = val; 356 else if (r_type == R_390_GOTPCDBL) 357 *(unsigned int *) loc = val >> 1; 358 break; 359 case R_390_COPY: 360 case R_390_GLOB_DAT: /* Create GOT entry. */ 361 case R_390_JMP_SLOT: /* Create PLT entry. */ 362 case R_390_RELATIVE: /* Adjust by program base. */ 363 /* Only needed if we want to support loading of 364 modules linked with -shared. */ 365 break; 366 default: 367 printk(KERN_ERR "module %s: Unknown relocation: %u\n", 368 me->name, r_type); 369 return -ENOEXEC; 370 } 371 return 0; 372} 373 374int 375apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, 376 unsigned int symindex, unsigned int relsec, 377 struct module *me) 378{ 379 Elf_Addr base; 380 Elf_Sym *symtab; 381 Elf_Rela *rela; 382 unsigned long i, n; 383 int rc; 384 385 DEBUGP("Applying relocate section %u to %u\n", 386 relsec, sechdrs[relsec].sh_info); 387 base = sechdrs[sechdrs[relsec].sh_info].sh_addr; 388 symtab = (Elf_Sym *) sechdrs[symindex].sh_addr; 389 rela = (Elf_Rela *) sechdrs[relsec].sh_addr; 390 n = sechdrs[relsec].sh_size / sizeof(Elf_Rela); 391 392 for (i = 0; i < n; i++, rela++) { 393 rc = apply_rela(rela, base, symtab, me); 394 if (rc) 395 return rc; 396 } 397 return 0; 398} 399 400int module_finalize(const Elf_Ehdr *hdr, 401 const Elf_Shdr *sechdrs, 402 struct module *me) 403{ 404 vfree(me->arch.syminfo); 405 me->arch.syminfo = NULL; 406 return 0; 407} 408 409void module_arch_cleanup(struct module *mod) 410{ 411} 412