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