LXR linux/arch/s390/kernel/module.c

   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
  48void *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 */
  56void 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
  65static void
  66check_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 */
 115int
 116module_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
 179int
 180apply_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
 188static int
 189apply_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
 378int
 379apply_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
 404int 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
 413void module_arch_cleanup(struct module *mod)
 414{
 415}
 416