linux/arch/mips/kernel/module.c
<<
>>
Prefs
   1/*
   2 *  This program is free software; you can redistribute it and/or modify
   3 *  it under the terms of the GNU General Public License as published by
   4 *  the Free Software Foundation; either version 2 of the License, or
   5 *  (at your option) any later version.
   6 *
   7 *  This program is distributed in the hope that it will be useful,
   8 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   9 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10 *  GNU General Public License for more details.
  11 *
  12 *  You should have received a copy of the GNU General Public License
  13 *  along with this program; if not, write to the Free Software
  14 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  15 *
  16 *  Copyright (C) 2001 Rusty Russell.
  17 *  Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
  18 *  Copyright (C) 2005 Thiemo Seufer
  19 */
  20
  21#undef DEBUG
  22
  23#include <linux/moduleloader.h>
  24#include <linux/elf.h>
  25#include <linux/mm.h>
  26#include <linux/vmalloc.h>
  27#include <linux/slab.h>
  28#include <linux/fs.h>
  29#include <linux/string.h>
  30#include <linux/kernel.h>
  31#include <linux/module.h>
  32#include <linux/spinlock.h>
  33#include <asm/pgtable.h>        /* MODULE_START */
  34
  35struct mips_hi16 {
  36        struct mips_hi16 *next;
  37        Elf_Addr *addr;
  38        Elf_Addr value;
  39};
  40
  41static struct mips_hi16 *mips_hi16_list;
  42
  43static LIST_HEAD(dbe_list);
  44static DEFINE_SPINLOCK(dbe_lock);
  45
  46void *module_alloc(unsigned long size)
  47{
  48#ifdef MODULE_START
  49        struct vm_struct *area;
  50
  51        size = PAGE_ALIGN(size);
  52        if (!size)
  53                return NULL;
  54
  55        area = __get_vm_area(size, VM_ALLOC, MODULE_START, MODULE_END);
  56        if (!area)
  57                return NULL;
  58
  59        return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL);
  60#else
  61        if (size == 0)
  62                return NULL;
  63        return vmalloc(size);
  64#endif
  65}
  66
  67/* Free memory returned from module_alloc */
  68void module_free(struct module *mod, void *module_region)
  69{
  70        vfree(module_region);
  71        /* FIXME: If module_region == mod->init_region, trim exception
  72           table entries. */
  73}
  74
  75int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
  76                              char *secstrings, struct module *mod)
  77{
  78        return 0;
  79}
  80
  81static int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v)
  82{
  83        return 0;
  84}
  85
  86static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v)
  87{
  88        *location += v;
  89
  90        return 0;
  91}
  92
  93static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v)
  94{
  95        *location = v;
  96
  97        return 0;
  98}
  99
 100static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v)
 101{
 102        if (v % 4) {
 103                printk(KERN_ERR "module %s: dangerous relocation\n", me->name);
 104                return -ENOEXEC;
 105        }
 106
 107        if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
 108                printk(KERN_ERR
 109                       "module %s: relocation overflow\n",
 110                       me->name);
 111                return -ENOEXEC;
 112        }
 113
 114        *location = (*location & ~0x03ffffff) |
 115                    ((*location + (v >> 2)) & 0x03ffffff);
 116
 117        return 0;
 118}
 119
 120static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v)
 121{
 122        if (v % 4) {
 123                printk(KERN_ERR "module %s: dangerous relocation\n", me->name);
 124                return -ENOEXEC;
 125        }
 126
 127        if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
 128                printk(KERN_ERR
 129                       "module %s: relocation overflow\n",
 130                       me->name);
 131                return -ENOEXEC;
 132        }
 133
 134        *location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff);
 135
 136        return 0;
 137}
 138
 139static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v)
 140{
 141        struct mips_hi16 *n;
 142
 143        /*
 144         * We cannot relocate this one now because we don't know the value of
 145         * the carry we need to add.  Save the information, and let LO16 do the
 146         * actual relocation.
 147         */
 148        n = kmalloc(sizeof *n, GFP_KERNEL);
 149        if (!n)
 150                return -ENOMEM;
 151
 152        n->addr = (Elf_Addr *)location;
 153        n->value = v;
 154        n->next = mips_hi16_list;
 155        mips_hi16_list = n;
 156
 157        return 0;
 158}
 159
 160static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v)
 161{
 162        *location = (*location & 0xffff0000) |
 163                    ((((long long) v + 0x8000LL) >> 16) & 0xffff);
 164
 165        return 0;
 166}
 167
 168static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v)
 169{
 170        unsigned long insnlo = *location;
 171        Elf_Addr val, vallo;
 172
 173        /* Sign extend the addend we extract from the lo insn.  */
 174        vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
 175
 176        if (mips_hi16_list != NULL) {
 177                struct mips_hi16 *l;
 178
 179                l = mips_hi16_list;
 180                while (l != NULL) {
 181                        struct mips_hi16 *next;
 182                        unsigned long insn;
 183
 184                        /*
 185                         * The value for the HI16 had best be the same.
 186                         */
 187                        if (v != l->value)
 188                                goto out_danger;
 189
 190                        /*
 191                         * Do the HI16 relocation.  Note that we actually don't
 192                         * need to know anything about the LO16 itself, except
 193                         * where to find the low 16 bits of the addend needed
 194                         * by the LO16.
 195                         */
 196                        insn = *l->addr;
 197                        val = ((insn & 0xffff) << 16) + vallo;
 198                        val += v;
 199
 200                        /*
 201                         * Account for the sign extension that will happen in
 202                         * the low bits.
 203                         */
 204                        val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
 205
 206                        insn = (insn & ~0xffff) | val;
 207                        *l->addr = insn;
 208
 209                        next = l->next;
 210                        kfree(l);
 211                        l = next;
 212                }
 213
 214                mips_hi16_list = NULL;
 215        }
 216
 217        /*
 218         * Ok, we're done with the HI16 relocs.  Now deal with the LO16.
 219         */
 220        val = v + vallo;
 221        insnlo = (insnlo & ~0xffff) | (val & 0xffff);
 222        *location = insnlo;
 223
 224        return 0;
 225
 226out_danger:
 227        printk(KERN_ERR "module %s: dangerous " "relocation\n", me->name);
 228
 229        return -ENOEXEC;
 230}
 231
 232static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v)
 233{
 234        *location = (*location & 0xffff0000) | (v & 0xffff);
 235
 236        return 0;
 237}
 238
 239static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v)
 240{
 241        *(Elf_Addr *)location = v;
 242
 243        return 0;
 244}
 245
 246static int apply_r_mips_higher_rela(struct module *me, u32 *location,
 247                                    Elf_Addr v)
 248{
 249        *location = (*location & 0xffff0000) |
 250                    ((((long long) v + 0x80008000LL) >> 32) & 0xffff);
 251
 252        return 0;
 253}
 254
 255static int apply_r_mips_highest_rela(struct module *me, u32 *location,
 256                                     Elf_Addr v)
 257{
 258        *location = (*location & 0xffff0000) |
 259                    ((((long long) v + 0x800080008000LL) >> 48) & 0xffff);
 260
 261        return 0;
 262}
 263
 264static int (*reloc_handlers_rel[]) (struct module *me, u32 *location,
 265                                Elf_Addr v) = {
 266        [R_MIPS_NONE]           = apply_r_mips_none,
 267        [R_MIPS_32]             = apply_r_mips_32_rel,
 268        [R_MIPS_26]             = apply_r_mips_26_rel,
 269        [R_MIPS_HI16]           = apply_r_mips_hi16_rel,
 270        [R_MIPS_LO16]           = apply_r_mips_lo16_rel
 271};
 272
 273static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
 274                                Elf_Addr v) = {
 275        [R_MIPS_NONE]           = apply_r_mips_none,
 276        [R_MIPS_32]             = apply_r_mips_32_rela,
 277        [R_MIPS_26]             = apply_r_mips_26_rela,
 278        [R_MIPS_HI16]           = apply_r_mips_hi16_rela,
 279        [R_MIPS_LO16]           = apply_r_mips_lo16_rela,
 280        [R_MIPS_64]             = apply_r_mips_64_rela,
 281        [R_MIPS_HIGHER]         = apply_r_mips_higher_rela,
 282        [R_MIPS_HIGHEST]        = apply_r_mips_highest_rela
 283};
 284
 285int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
 286                   unsigned int symindex, unsigned int relsec,
 287                   struct module *me)
 288{
 289        Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr;
 290        Elf_Sym *sym;
 291        u32 *location;
 292        unsigned int i;
 293        Elf_Addr v;
 294        int res;
 295
 296        pr_debug("Applying relocate section %u to %u\n", relsec,
 297               sechdrs[relsec].sh_info);
 298
 299        for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 300                /* This is where to make the change */
 301                location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 302                        + rel[i].r_offset;
 303                /* This is the symbol it is referring to */
 304                sym = (Elf_Sym *)sechdrs[symindex].sh_addr
 305                        + ELF_MIPS_R_SYM(rel[i]);
 306                if (!sym->st_value) {
 307                        /* Ignore unresolved weak symbol */
 308                        if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
 309                                continue;
 310                        printk(KERN_WARNING "%s: Unknown symbol %s\n",
 311                               me->name, strtab + sym->st_name);
 312                        return -ENOENT;
 313                }
 314
 315                v = sym->st_value;
 316
 317                res = reloc_handlers_rel[ELF_MIPS_R_TYPE(rel[i])](me, location, v);
 318                if (res)
 319                        return res;
 320        }
 321
 322        return 0;
 323}
 324
 325int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
 326                       unsigned int symindex, unsigned int relsec,
 327                       struct module *me)
 328{
 329        Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr;
 330        Elf_Sym *sym;
 331        u32 *location;
 332        unsigned int i;
 333        Elf_Addr v;
 334        int res;
 335
 336        pr_debug("Applying relocate section %u to %u\n", relsec,
 337               sechdrs[relsec].sh_info);
 338
 339        for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 340                /* This is where to make the change */
 341                location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 342                        + rel[i].r_offset;
 343                /* This is the symbol it is referring to */
 344                sym = (Elf_Sym *)sechdrs[symindex].sh_addr
 345                        + ELF_MIPS_R_SYM(rel[i]);
 346                if (!sym->st_value) {
 347                        /* Ignore unresolved weak symbol */
 348                        if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
 349                                continue;
 350                        printk(KERN_WARNING "%s: Unknown symbol %s\n",
 351                               me->name, strtab + sym->st_name);
 352                        return -ENOENT;
 353                }
 354
 355                v = sym->st_value + rel[i].r_addend;
 356
 357                res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v);
 358                if (res)
 359                        return res;
 360        }
 361
 362        return 0;
 363}
 364
 365/* Given an address, look for it in the module exception tables. */
 366const struct exception_table_entry *search_module_dbetables(unsigned long addr)
 367{
 368        unsigned long flags;
 369        const struct exception_table_entry *e = NULL;
 370        struct mod_arch_specific *dbe;
 371
 372        spin_lock_irqsave(&dbe_lock, flags);
 373        list_for_each_entry(dbe, &dbe_list, dbe_list) {
 374                e = search_extable(dbe->dbe_start, dbe->dbe_end - 1, addr);
 375                if (e)
 376                        break;
 377        }
 378        spin_unlock_irqrestore(&dbe_lock, flags);
 379
 380        /* Now, if we found one, we are running inside it now, hence
 381           we cannot unload the module, hence no refcnt needed. */
 382        return e;
 383}
 384
 385/* Put in dbe list if necessary. */
 386int module_finalize(const Elf_Ehdr *hdr,
 387                    const Elf_Shdr *sechdrs,
 388                    struct module *me)
 389{
 390        const Elf_Shdr *s;
 391        char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 392
 393        INIT_LIST_HEAD(&me->arch.dbe_list);
 394        for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
 395                if (strcmp("__dbe_table", secstrings + s->sh_name) != 0)
 396                        continue;
 397                me->arch.dbe_start = (void *)s->sh_addr;
 398                me->arch.dbe_end = (void *)s->sh_addr + s->sh_size;
 399                spin_lock_irq(&dbe_lock);
 400                list_add(&me->arch.dbe_list, &dbe_list);
 401                spin_unlock_irq(&dbe_lock);
 402        }
 403        return 0;
 404}
 405
 406void module_arch_cleanup(struct module *mod)
 407{
 408        spin_lock_irq(&dbe_lock);
 409        list_del(&mod->arch.dbe_list);
 410        spin_unlock_irq(&dbe_lock);
 411}
 412