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 + ~PGDIR_MASK) & PGDIR_MASK)
  37 #endif
  38
  39 #ifdef CONFIG_MMU
  40 void *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 #else /* CONFIG_MMU */
  47 void *module_alloc(unsigned long size)
  48 {
  49         return size == 0 ? NULL : vmalloc(size);
  50 }
  51 #endif /* !CONFIG_MMU */
  52
  53 void module_free(struct module *module, void *region)
  54 {
  55         vfree(region);
  56 }
  57
  58 int module_frob_arch_sections(Elf_Ehdr *hdr,
  59                               Elf_Shdr *sechdrs,
  60                               char *secstrings,
  61                               struct module *mod)
  62 {
  63         return 0;
  64 }
  65
  66 int
  67 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
  68                unsigned int relindex, struct module *module)
  69 {
  70         Elf32_Shdr *symsec = sechdrs + symindex;
  71         Elf32_Shdr *relsec = sechdrs + relindex;
  72         Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
  73         Elf32_Rel *rel = (void *)relsec->sh_addr;
  74         unsigned int i;
  75
  76         for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
  77                 unsigned long loc;
  78                 Elf32_Sym *sym;
  79                 const char *symname;
  80                 s32 offset;
  81 #ifdef CONFIG_THUMB2_KERNEL
  82                 u32 upper, lower, sign, j1, j2;
  83 #endif
  84
  85                 offset = ELF32_R_SYM(rel->r_info);
  86                 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
  87                         pr_err("%s: section %u reloc %u: bad relocation sym offset\n",
  88                                 module->name, relindex, i);
  89                         return -ENOEXEC;
  90                 }
  91
  92                 sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
  93                 symname = strtab + sym->st_name;
  94
  95                 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
  96                         pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n",
  97                                module->name, relindex, i, symname,
  98                                rel->r_offset, dstsec->sh_size);
  99                         return -ENOEXEC;
 100                 }
 101
 102                 loc = dstsec->sh_addr + rel->r_offset;
 103
 104                 switch (ELF32_R_TYPE(rel->r_info)) {
 105                 case R_ARM_NONE:
 106                         /* ignore */
 107                         break;
 108
 109                 case R_ARM_ABS32:
 110                         *(u32 *)loc += sym->st_value;
 111                         break;
 112
 113                 case R_ARM_PC24:
 114                 case R_ARM_CALL:
 115                 case R_ARM_JUMP24:
 116                         offset = (*(u32 *)loc & 0x00ffffff) << 2;
 117                         if (offset & 0x02000000)
 118                                 offset -= 0x04000000;
 119
 120                         offset += sym->st_value - loc;
 121                         if (offset & 3 ||
 122                             offset <= (s32)0xfe000000 ||
 123                             offset >= (s32)0x02000000) {
 124                                 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
 125                                        module->name, relindex, i, symname,
 126                                        ELF32_R_TYPE(rel->r_info), loc,
 127                                        sym->st_value);
 128                                 return -ENOEXEC;
 129                         }
 130
 131                         offset >>= 2;
 132
 133                         *(u32 *)loc &= 0xff000000;
 134                         *(u32 *)loc |= offset & 0x00ffffff;
 135                         break;
 136
 137                case R_ARM_V4BX:
 138                        /* Preserve Rm and the condition code. Alter
 139                         * other bits to re-code instruction as
 140                         * MOV PC,Rm.
 141                         */
 142                        *(u32 *)loc &= 0xf000000f;
 143                        *(u32 *)loc |= 0x01a0f000;
 144                        break;
 145
 146                 case R_ARM_PREL31:
 147                         offset = *(u32 *)loc + sym->st_value - loc;
 148                         *(u32 *)loc = offset & 0x7fffffff;
 149                         break;
 150
 151                 case R_ARM_MOVW_ABS_NC:
 152                 case R_ARM_MOVT_ABS:
 153                         offset = *(u32 *)loc;
 154                         offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
 155                         offset = (offset ^ 0x8000) - 0x8000;
 156
 157                         offset += sym->st_value;
 158                         if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS)
 159                                 offset >>= 16;
 160
 161                         *(u32 *)loc &= 0xfff0f000;
 162                         *(u32 *)loc |= ((offset & 0xf000) << 4) |
 163                                         (offset & 0x0fff);
 164                         break;
 165
 166 #ifdef CONFIG_THUMB2_KERNEL
 167                 case R_ARM_THM_CALL:
 168                 case R_ARM_THM_JUMP24:
 169                         upper = *(u16 *)loc;
 170                         lower = *(u16 *)(loc + 2);
 171
 172                         /*
 173                          * 25 bit signed address range (Thumb-2 BL and B.W
 174                          * instructions):
 175                          *   S:I1:I2:imm10:imm11:0
 176                          * where:
 177                          *   S     = upper[10]   = offset[24]
 178                          *   I1    = ~(J1 ^ S)   = offset[23]
 179                          *   I2    = ~(J2 ^ S)   = offset[22]
 180                          *   imm10 = upper[9:0]  = offset[21:12]
 181                          *   imm11 = lower[10:0] = offset[11:1]
 182                          *   J1    = lower[13]
 183                          *   J2    = lower[11]
 184                          */
 185                         sign = (upper >> 10) & 1;
 186                         j1 = (lower >> 13) & 1;
 187                         j2 = (lower >> 11) & 1;
 188                         offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
 189                                 ((~(j2 ^ sign) & 1) << 22) |
 190                                 ((upper & 0x03ff) << 12) |
 191                                 ((lower & 0x07ff) << 1);
 192                         if (offset & 0x01000000)
 193                                 offset -= 0x02000000;
 194                         offset += sym->st_value - loc;
 195
 196                         /*
 197                          * For function symbols, only Thumb addresses are
 198                          * allowed (no interworking).
 199                          *
 200                          * For non-function symbols, the destination
 201                          * has no specific ARM/Thumb disposition, so
 202                          * the branch is resolved under the assumption
 203                          * that interworking is not required.
 204                          */
 205                         if ((ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
 206                                 !(offset & 1)) ||
 207                             offset <= (s32)0xff000000 ||
 208                             offset >= (s32)0x01000000) {
 209                                 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
 210                                        module->name, relindex, i, symname,
 211                                        ELF32_R_TYPE(rel->r_info), loc,
 212                                        sym->st_value);
 213                                 return -ENOEXEC;
 214                         }
 215
 216                         sign = (offset >> 24) & 1;
 217                         j1 = sign ^ (~(offset >> 23) & 1);
 218                         j2 = sign ^ (~(offset >> 22) & 1);
 219                         *(u16 *)loc = (u16)((upper & 0xf800) | (sign << 10) |
 220                                             ((offset >> 12) & 0x03ff));
 221                         *(u16 *)(loc + 2) = (u16)((lower & 0xd000) |
 222                                                   (j1 << 13) | (j2 << 11) |
 223                                                   ((offset >> 1) & 0x07ff));
 224                         break;
 225
 226                 case R_ARM_THM_MOVW_ABS_NC:
 227                 case R_ARM_THM_MOVT_ABS:
 228                         upper = *(u16 *)loc;
 229                         lower = *(u16 *)(loc + 2);
 230
 231                         /*
 232                          * MOVT/MOVW instructions encoding in Thumb-2:
 233                          *
 234                          * i    = upper[10]
 235                          * imm4 = upper[3:0]
 236                          * imm3 = lower[14:12]
 237                          * imm8 = lower[7:0]
 238                          *
 239                          * imm16 = imm4:i:imm3:imm8
 240                          */
 241                         offset = ((upper & 0x000f) << 12) |
 242                                 ((upper & 0x0400) << 1) |
 243                                 ((lower & 0x7000) >> 4) | (lower & 0x00ff);
 244                         offset = (offset ^ 0x8000) - 0x8000;
 245                         offset += sym->st_value;
 246
 247                         if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS)
 248                                 offset >>= 16;
 249
 250                         *(u16 *)loc = (u16)((upper & 0xfbf0) |
 251                                             ((offset & 0xf000) >> 12) |
 252                                             ((offset & 0x0800) >> 1));
 253                         *(u16 *)(loc + 2) = (u16)((lower & 0x8f00) |
 254                                                   ((offset & 0x0700) << 4) |
 255                                                   (offset & 0x00ff));
 256                         break;
 257 #endif
 258
 259                 default:
 260                         printk(KERN_ERR "%s: unknown relocation: %u\n",
 261                                module->name, ELF32_R_TYPE(rel->r_info));
 262                         return -ENOEXEC;
 263                 }
 264         }
 265         return 0;
 266 }
 267
 268 int
 269 apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
 270                    unsigned int symindex, unsigned int relsec, struct module *module)
 271 {
 272         printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
 273                module->name);
 274         return -ENOEXEC;
 275 }
 276
 277 struct mod_unwind_map {
 278         const Elf_Shdr *unw_sec;
 279         const Elf_Shdr *txt_sec;
 280 };
 281
 282 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
 283         const Elf_Shdr *sechdrs, const char *name)
 284 {
 285         const Elf_Shdr *s, *se;
 286         const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 287
 288         for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
 289                 if (strcmp(name, secstrs + s->sh_name) == 0)
 290                         return s;
 291
 292         return NULL;
 293 }
 294
 295 extern void fixup_pv_table(const void *, unsigned long);
 296 extern void fixup_smp(const void *, unsigned long);
 297
 298 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 299                     struct module *mod)
 300 {
 301         const Elf_Shdr *s = NULL;
 302 #ifdef CONFIG_ARM_UNWIND
 303         const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 304         const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
 305         struct mod_unwind_map maps[ARM_SEC_MAX];
 306         int i;
 307
 308         memset(maps, 0, sizeof(maps));
 309
 310         for (s = sechdrs; s < sechdrs_end; s++) {
 311                 const char *secname = secstrs + s->sh_name;
 312
 313                 if (!(s->sh_flags & SHF_ALLOC))
 314                         continue;
 315
 316                 if (strcmp(".ARM.exidx.init.text", secname) == 0)
 317                         maps[ARM_SEC_INIT].unw_sec = s;
 318                 else if (strcmp(".ARM.exidx.devinit.text", secname) == 0)
 319                         maps[ARM_SEC_DEVINIT].unw_sec = s;
 320                 else if (strcmp(".ARM.exidx", secname) == 0)
 321                         maps[ARM_SEC_CORE].unw_sec = s;
 322                 else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
 323                         maps[ARM_SEC_EXIT].unw_sec = s;
 324                 else if (strcmp(".ARM.exidx.devexit.text", secname) == 0)
 325                         maps[ARM_SEC_DEVEXIT].unw_sec = s;
 326                 else if (strcmp(".init.text", secname) == 0)
 327                         maps[ARM_SEC_INIT].txt_sec = s;
 328                 else if (strcmp(".devinit.text", secname) == 0)
 329                         maps[ARM_SEC_DEVINIT].txt_sec = s;
 330                 else if (strcmp(".text", secname) == 0)
 331                         maps[ARM_SEC_CORE].txt_sec = s;
 332                 else if (strcmp(".exit.text", secname) == 0)
 333                         maps[ARM_SEC_EXIT].txt_sec = s;
 334                 else if (strcmp(".devexit.text", secname) == 0)
 335                         maps[ARM_SEC_DEVEXIT].txt_sec = s;
 336         }
 337
 338         for (i = 0; i < ARM_SEC_MAX; i++)
 339                 if (maps[i].unw_sec && maps[i].txt_sec)
 340                         mod->arch.unwind[i] =
 341                                 unwind_table_add(maps[i].unw_sec->sh_addr,
 342                                                  maps[i].unw_sec->sh_size,
 343                                                  maps[i].txt_sec->sh_addr,
 344                                                  maps[i].txt_sec->sh_size);
 345 #endif
 346 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT
 347         s = find_mod_section(hdr, sechdrs, ".pv_table");
 348         if (s)
 349                 fixup_pv_table((void *)s->sh_addr, s->sh_size);
 350 #endif
 351         s = find_mod_section(hdr, sechdrs, ".alt.smp.init");
 352         if (s && !is_smp())
 353                 fixup_smp((void *)s->sh_addr, s->sh_size);
 354         return 0;
 355 }
 356
 357 void
 358 module_arch_cleanup(struct module *mod)
 359 {
 360 #ifdef CONFIG_ARM_UNWIND
 361         int i;
 362
 363         for (i = 0; i < ARM_SEC_MAX; i++)
 364                 if (mod->arch.unwind[i])
 365                         unwind_table_del(mod->arch.unwind[i]);
 366 #endif
 367 }