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