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

   1/*
   2 *  linux/arch/arm/kernel/module.c
   3 *
   4 *  Copyright (C) 2002 Russell King.
   5 *  Modified for nommu by Hyok S. Choi
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 *
  11 * Module allocation method suggested by Andi Kleen.
  12 */
  13#include <linux/module.h>
  14#include <linux/moduleloader.h>
  15#include <linux/kernel.h>
  16#include <linux/mm.h>
  17#include <linux/elf.h>
  18#include <linux/vmalloc.h>
  19#include <linux/fs.h>
  20#include <linux/string.h>
  21#include <linux/gfp.h>
  22
  23#include <asm/pgtable.h>
  24#include <asm/sections.h>
  25#include <asm/smp_plat.h>
  26#include <asm/unwind.h>
  27
  28#ifdef CONFIG_XIP_KERNEL
  29/*
  30 * The XIP kernel text is mapped in the module area for modules and
  31 * some other stuff to work without any indirect relocations.
  32 * MODULES_VADDR is redefined here and not in asm/memory.h to avoid
  33 * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
  34 */
  35#undef MODULES_VADDR
  36#define MODULES_VADDR   (((unsigned long)_etext + ~PMD_MASK) & PMD_MASK)
  37#endif
  38
  39#ifdef CONFIG_MMU
  40void *module_alloc(unsigned long size)
  41{
  42        return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
  43                                GFP_KERNEL, PAGE_KERNEL_EXEC, -1,
  44                                __builtin_return_address(0));
  45}
  46#endif
  47
  48int
  49apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
  50               unsigned int relindex, struct module *module)
  51{
  52        Elf32_Shdr *symsec = sechdrs + symindex;
  53        Elf32_Shdr *relsec = sechdrs + relindex;
  54        Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
  55        Elf32_Rel *rel = (void *)relsec->sh_addr;
  56        unsigned int i;
  57
  58        for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
  59                unsigned long loc;
  60                Elf32_Sym *sym;
  61                const char *symname;
  62                s32 offset;
  63#ifdef CONFIG_THUMB2_KERNEL
  64                u32 upper, lower, sign, j1, j2;
  65#endif
  66
  67                offset = ELF32_R_SYM(rel->r_info);
  68                if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
  69                        pr_err("%s: section %u reloc %u: bad relocation sym offset\n",
  70                                module->name, relindex, i);
  71                        return -ENOEXEC;
  72                }
  73
  74                sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
  75                symname = strtab + sym->st_name;
  76
  77                if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
  78                        pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n",
  79                               module->name, relindex, i, symname,
  80                               rel->r_offset, dstsec->sh_size);
  81                        return -ENOEXEC;
  82                }
  83
  84                loc = dstsec->sh_addr + rel->r_offset;
  85
  86                switch (ELF32_R_TYPE(rel->r_info)) {
  87                case R_ARM_NONE:
  88                        /* ignore */
  89                        break;
  90
  91                case R_ARM_ABS32:
  92                        *(u32 *)loc += sym->st_value;
  93                        break;
  94
  95                case R_ARM_PC24:
  96                case R_ARM_CALL:
  97                case R_ARM_JUMP24:
  98                        offset = (*(u32 *)loc & 0x00ffffff) << 2;
  99                        if (offset & 0x02000000)
 100                                offset -= 0x04000000;
 101
 102                        offset += sym->st_value - loc;
 103                        if (offset & 3 ||
 104                            offset <= (s32)0xfe000000 ||
 105                            offset >= (s32)0x02000000) {
 106                                pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
 107                                       module->name, relindex, i, symname,
 108                                       ELF32_R_TYPE(rel->r_info), loc,
 109                                       sym->st_value);
 110                                return -ENOEXEC;
 111                        }
 112
 113                        offset >>= 2;
 114
 115                        *(u32 *)loc &= 0xff000000;
 116                        *(u32 *)loc |= offset & 0x00ffffff;
 117                        break;
 118
 119               case R_ARM_V4BX:
 120                       /* Preserve Rm and the condition code. Alter
 121                        * other bits to re-code instruction as
 122                        * MOV PC,Rm.
 123                        */
 124                       *(u32 *)loc &= 0xf000000f;
 125                       *(u32 *)loc |= 0x01a0f000;
 126                       break;
 127
 128                case R_ARM_PREL31:
 129                        offset = *(u32 *)loc + sym->st_value - loc;
 130                        *(u32 *)loc = offset & 0x7fffffff;
 131                        break;
 132
 133                case R_ARM_MOVW_ABS_NC:
 134                case R_ARM_MOVT_ABS:
 135                        offset = *(u32 *)loc;
 136                        offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
 137                        offset = (offset ^ 0x8000) - 0x8000;
 138
 139                        offset += sym->st_value;
 140                        if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS)
 141                                offset >>= 16;
 142
 143                        *(u32 *)loc &= 0xfff0f000;
 144                        *(u32 *)loc |= ((offset & 0xf000) << 4) |
 145                                        (offset & 0x0fff);
 146                        break;
 147
 148#ifdef CONFIG_THUMB2_KERNEL
 149                case R_ARM_THM_CALL:
 150                case R_ARM_THM_JUMP24:
 151                        upper = *(u16 *)loc;
 152                        lower = *(u16 *)(loc + 2);
 153
 154                        /*
 155                         * 25 bit signed address range (Thumb-2 BL and B.W
 156                         * instructions):
 157                         *   S:I1:I2:imm10:imm11:0
 158                         * where:
 159                         *   S     = upper[10]   = offset[24]
 160                         *   I1    = ~(J1 ^ S)   = offset[23]
 161                         *   I2    = ~(J2 ^ S)   = offset[22]
 162                         *   imm10 = upper[9:0]  = offset[21:12]
 163                         *   imm11 = lower[10:0] = offset[11:1]
 164                         *   J1    = lower[13]
 165                         *   J2    = lower[11]
 166                         */
 167                        sign = (upper >> 10) & 1;
 168                        j1 = (lower >> 13) & 1;
 169                        j2 = (lower >> 11) & 1;
 170                        offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
 171                                ((~(j2 ^ sign) & 1) << 22) |
 172                                ((upper & 0x03ff) << 12) |
 173                                ((lower & 0x07ff) << 1);
 174                        if (offset & 0x01000000)
 175                                offset -= 0x02000000;
 176                        offset += sym->st_value - loc;
 177
 178                        /*
 179                         * For function symbols, only Thumb addresses are
 180                         * allowed (no interworking).
 181                         *
 182                         * For non-function symbols, the destination
 183                         * has no specific ARM/Thumb disposition, so
 184                         * the branch is resolved under the assumption
 185                         * that interworking is not required.
 186                         */
 187                        if ((ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
 188                                !(offset & 1)) ||
 189                            offset <= (s32)0xff000000 ||
 190                            offset >= (s32)0x01000000) {
 191                                pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
 192                                       module->name, relindex, i, symname,
 193                                       ELF32_R_TYPE(rel->r_info), loc,
 194                                       sym->st_value);
 195                                return -ENOEXEC;
 196                        }
 197
 198                        sign = (offset >> 24) & 1;
 199                        j1 = sign ^ (~(offset >> 23) & 1);
 200                        j2 = sign ^ (~(offset >> 22) & 1);
 201                        *(u16 *)loc = (u16)((upper & 0xf800) | (sign << 10) |
 202                                            ((offset >> 12) & 0x03ff));
 203                        *(u16 *)(loc + 2) = (u16)((lower & 0xd000) |
 204                                                  (j1 << 13) | (j2 << 11) |
 205                                                  ((offset >> 1) & 0x07ff));
 206                        break;
 207
 208                case R_ARM_THM_MOVW_ABS_NC:
 209                case R_ARM_THM_MOVT_ABS:
 210                        upper = *(u16 *)loc;
 211                        lower = *(u16 *)(loc + 2);
 212
 213                        /*
 214                         * MOVT/MOVW instructions encoding in Thumb-2:
 215                         *
 216                         * i    = upper[10]
 217                         * imm4 = upper[3:0]
 218                         * imm3 = lower[14:12]
 219                         * imm8 = lower[7:0]
 220                         *
 221                         * imm16 = imm4:i:imm3:imm8
 222                         */
 223                        offset = ((upper & 0x000f) << 12) |
 224                                ((upper & 0x0400) << 1) |
 225                                ((lower & 0x7000) >> 4) | (lower & 0x00ff);
 226                        offset = (offset ^ 0x8000) - 0x8000;
 227                        offset += sym->st_value;
 228
 229                        if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS)
 230                                offset >>= 16;
 231
 232                        *(u16 *)loc = (u16)((upper & 0xfbf0) |
 233                                            ((offset & 0xf000) >> 12) |
 234                                            ((offset & 0x0800) >> 1));
 235                        *(u16 *)(loc + 2) = (u16)((lower & 0x8f00) |
 236                                                  ((offset & 0x0700) << 4) |
 237                                                  (offset & 0x00ff));
 238                        break;
 239#endif
 240
 241                default:
 242                        printk(KERN_ERR "%s: unknown relocation: %u\n",
 243                               module->name, ELF32_R_TYPE(rel->r_info));
 244                        return -ENOEXEC;
 245                }
 246        }
 247        return 0;
 248}
 249
 250struct mod_unwind_map {
 251        const Elf_Shdr *unw_sec;
 252        const Elf_Shdr *txt_sec;
 253};
 254
 255static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
 256        const Elf_Shdr *sechdrs, const char *name)
 257{
 258        const Elf_Shdr *s, *se;
 259        const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 260
 261        for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
 262                if (strcmp(name, secstrs + s->sh_name) == 0)
 263                        return s;
 264
 265        return NULL;
 266}
 267
 268extern void fixup_pv_table(const void *, unsigned long);
 269extern void fixup_smp(const void *, unsigned long);
 270
 271int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 272                    struct module *mod)
 273{
 274        const Elf_Shdr *s = NULL;
 275#ifdef CONFIG_ARM_UNWIND
 276        const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 277        const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
 278        struct mod_unwind_map maps[ARM_SEC_MAX];
 279        int i;
 280
 281        memset(maps, 0, sizeof(maps));
 282
 283        for (s = sechdrs; s < sechdrs_end; s++) {
 284                const char *secname = secstrs + s->sh_name;
 285
 286                if (!(s->sh_flags & SHF_ALLOC))
 287                        continue;
 288
 289                if (strcmp(".ARM.exidx.init.text", secname) == 0)
 290                        maps[ARM_SEC_INIT].unw_sec = s;
 291                else if (strcmp(".ARM.exidx.devinit.text", secname) == 0)
 292                        maps[ARM_SEC_DEVINIT].unw_sec = s;
 293                else if (strcmp(".ARM.exidx", secname) == 0)
 294                        maps[ARM_SEC_CORE].unw_sec = s;
 295                else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
 296                        maps[ARM_SEC_EXIT].unw_sec = s;
 297                else if (strcmp(".ARM.exidx.devexit.text", secname) == 0)
 298                        maps[ARM_SEC_DEVEXIT].unw_sec = s;
 299                else if (strcmp(".init.text", secname) == 0)
 300                        maps[ARM_SEC_INIT].txt_sec = s;
 301                else if (strcmp(".devinit.text", secname) == 0)
 302                        maps[ARM_SEC_DEVINIT].txt_sec = s;
 303                else if (strcmp(".text", secname) == 0)
 304                        maps[ARM_SEC_CORE].txt_sec = s;
 305                else if (strcmp(".exit.text", secname) == 0)
 306                        maps[ARM_SEC_EXIT].txt_sec = s;
 307                else if (strcmp(".devexit.text", secname) == 0)
 308                        maps[ARM_SEC_DEVEXIT].txt_sec = s;
 309        }
 310
 311        for (i = 0; i < ARM_SEC_MAX; i++)
 312                if (maps[i].unw_sec && maps[i].txt_sec)
 313                        mod->arch.unwind[i] =
 314                                unwind_table_add(maps[i].unw_sec->sh_addr,
 315                                                 maps[i].unw_sec->sh_size,
 316                                                 maps[i].txt_sec->sh_addr,
 317                                                 maps[i].txt_sec->sh_size);
 318#endif
 319#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
 320        s = find_mod_section(hdr, sechdrs, ".pv_table");
 321        if (s)
 322                fixup_pv_table((void *)s->sh_addr, s->sh_size);
 323#endif
 324        s = find_mod_section(hdr, sechdrs, ".alt.smp.init");
 325        if (s && !is_smp())
 326#ifdef CONFIG_SMP_ON_UP
 327                fixup_smp((void *)s->sh_addr, s->sh_size);
 328#else
 329                return -EINVAL;
 330#endif
 331        return 0;
 332}
 333
 334void
 335module_arch_cleanup(struct module *mod)
 336{
 337#ifdef CONFIG_ARM_UNWIND
 338        int i;
 339
 340        for (i = 0; i < ARM_SEC_MAX; i++)
 341                if (mod->arch.unwind[i])
 342                        unwind_table_del(mod->arch.unwind[i]);
 343#endif
 344}
 345