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 #include <asm/opcodes.h>
  28
  29 #ifdef CONFIG_XIP_KERNEL
  30 /*
  31  * The XIP kernel text is mapped in the module area for modules and
  32  * some other stuff to work without any indirect relocations.
  33  * MODULES_VADDR is redefined here and not in asm/memory.h to avoid
  34  * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
  35  */
  36 #undef MODULES_VADDR
  37 #define MODULES_VADDR   (((unsigned long)_etext + ~PMD_MASK) & PMD_MASK)
  38 #endif
  39
  40 #ifdef CONFIG_MMU
  41 void *module_alloc(unsigned long size)
  42 {
  43         return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
  44                                 GFP_KERNEL, PAGE_KERNEL_EXEC, NUMA_NO_NODE,
  45                                 __builtin_return_address(0));
  46 }
  47 #endif
  48
  49 int
  50 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
  51                unsigned int relindex, struct module *module)
  52 {
  53         Elf32_Shdr *symsec = sechdrs + symindex;
  54         Elf32_Shdr *relsec = sechdrs + relindex;
  55         Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
  56         Elf32_Rel *rel = (void *)relsec->sh_addr;
  57         unsigned int i;
  58
  59         for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
  60                 unsigned long loc;
  61                 Elf32_Sym *sym;
  62                 const char *symname;
  63                 s32 offset;
  64                 u32 tmp;
  65 #ifdef CONFIG_THUMB2_KERNEL
  66                 u32 upper, lower, sign, j1, j2;
  67 #endif
  68
  69                 offset = ELF32_R_SYM(rel->r_info);
  70                 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
  71                         pr_err("%s: section %u reloc %u: bad relocation sym offset\n",
  72                                 module->name, relindex, i);
  73                         return -ENOEXEC;
  74                 }
  75
  76                 sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
  77                 symname = strtab + sym->st_name;
  78
  79                 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
  80                         pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n",
  81                                module->name, relindex, i, symname,
  82                                rel->r_offset, dstsec->sh_size);
  83                         return -ENOEXEC;
  84                 }
  85
  86                 loc = dstsec->sh_addr + rel->r_offset;
  87
  88                 switch (ELF32_R_TYPE(rel->r_info)) {
  89                 case R_ARM_NONE:
  90                         /* ignore */
  91                         break;
  92
  93                 case R_ARM_ABS32:
  94                 case R_ARM_TARGET1:
  95                         *(u32 *)loc += sym->st_value;
  96                         break;
  97
  98                 case R_ARM_PC24:
  99                 case R_ARM_CALL:
 100                 case R_ARM_JUMP24:
 101                         offset = __mem_to_opcode_arm(*(u32 *)loc);
 102                         offset = (offset & 0x00ffffff) << 2;
 103                         if (offset & 0x02000000)
 104                                 offset -= 0x04000000;
 105
 106                         offset += sym->st_value - loc;
 107                         if (offset & 3 ||
 108                             offset <= (s32)0xfe000000 ||
 109                             offset >= (s32)0x02000000) {
 110                                 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
 111                                        module->name, relindex, i, symname,
 112                                        ELF32_R_TYPE(rel->r_info), loc,
 113                                        sym->st_value);
 114                                 return -ENOEXEC;
 115                         }
 116
 117                         offset >>= 2;
 118                         offset &= 0x00ffffff;
 119
 120                         *(u32 *)loc &= __opcode_to_mem_arm(0xff000000);
 121                         *(u32 *)loc |= __opcode_to_mem_arm(offset);
 122                         break;
 123
 124                case R_ARM_V4BX:
 125                        /* Preserve Rm and the condition code. Alter
 126                         * other bits to re-code instruction as
 127                         * MOV PC,Rm.
 128                         */
 129                        *(u32 *)loc &= __opcode_to_mem_arm(0xf000000f);
 130                        *(u32 *)loc |= __opcode_to_mem_arm(0x01a0f000);
 131                        break;
 132
 133                 case R_ARM_PREL31:
 134                         offset = *(u32 *)loc + sym->st_value - loc;
 135                         *(u32 *)loc = offset & 0x7fffffff;
 136                         break;
 137
 138                 case R_ARM_MOVW_ABS_NC:
 139                 case R_ARM_MOVT_ABS:
 140                         offset = tmp = __mem_to_opcode_arm(*(u32 *)loc);
 141                         offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
 142                         offset = (offset ^ 0x8000) - 0x8000;
 143
 144                         offset += sym->st_value;
 145                         if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS)
 146                                 offset >>= 16;
 147
 148                         tmp &= 0xfff0f000;
 149                         tmp |= ((offset & 0xf000) << 4) |
 150                                 (offset & 0x0fff);
 151
 152                         *(u32 *)loc = __opcode_to_mem_arm(tmp);
 153                         break;
 154
 155 #ifdef CONFIG_THUMB2_KERNEL
 156                 case R_ARM_THM_CALL:
 157                 case R_ARM_THM_JUMP24:
 158                         upper = __mem_to_opcode_thumb16(*(u16 *)loc);
 159                         lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
 160
 161                         /*
 162                          * 25 bit signed address range (Thumb-2 BL and B.W
 163                          * instructions):
 164                          *   S:I1:I2:imm10:imm11:0
 165                          * where:
 166                          *   S     = upper[10]   = offset[24]
 167                          *   I1    = ~(J1 ^ S)   = offset[23]
 168                          *   I2    = ~(J2 ^ S)   = offset[22]
 169                          *   imm10 = upper[9:0]  = offset[21:12]
 170                          *   imm11 = lower[10:0] = offset[11:1]
 171                          *   J1    = lower[13]
 172                          *   J2    = lower[11]
 173                          */
 174                         sign = (upper >> 10) & 1;
 175                         j1 = (lower >> 13) & 1;
 176                         j2 = (lower >> 11) & 1;
 177                         offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
 178                                 ((~(j2 ^ sign) & 1) << 22) |
 179                                 ((upper & 0x03ff) << 12) |
 180                                 ((lower & 0x07ff) << 1);
 181                         if (offset & 0x01000000)
 182                                 offset -= 0x02000000;
 183                         offset += sym->st_value - loc;
 184
 185                         /*
 186                          * For function symbols, only Thumb addresses are
 187                          * allowed (no interworking).
 188                          *
 189                          * For non-function symbols, the destination
 190                          * has no specific ARM/Thumb disposition, so
 191                          * the branch is resolved under the assumption
 192                          * that interworking is not required.
 193                          */
 194                         if ((ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
 195                                 !(offset & 1)) ||
 196                             offset <= (s32)0xff000000 ||
 197                             offset >= (s32)0x01000000) {
 198                                 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
 199                                        module->name, relindex, i, symname,
 200                                        ELF32_R_TYPE(rel->r_info), loc,
 201                                        sym->st_value);
 202                                 return -ENOEXEC;
 203                         }
 204
 205                         sign = (offset >> 24) & 1;
 206                         j1 = sign ^ (~(offset >> 23) & 1);
 207                         j2 = sign ^ (~(offset >> 22) & 1);
 208                         upper = (u16)((upper & 0xf800) | (sign << 10) |
 209                                             ((offset >> 12) & 0x03ff));
 210                         lower = (u16)((lower & 0xd000) |
 211                                       (j1 << 13) | (j2 << 11) |
 212                                       ((offset >> 1) & 0x07ff));
 213
 214                         *(u16 *)loc = __opcode_to_mem_thumb16(upper);
 215                         *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
 216                         break;
 217
 218                 case R_ARM_THM_MOVW_ABS_NC:
 219                 case R_ARM_THM_MOVT_ABS:
 220                         upper = __mem_to_opcode_thumb16(*(u16 *)loc);
 221                         lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
 222
 223                         /*
 224                          * MOVT/MOVW instructions encoding in Thumb-2:
 225                          *
 226                          * i    = upper[10]
 227                          * imm4 = upper[3:0]
 228                          * imm3 = lower[14:12]
 229                          * imm8 = lower[7:0]
 230                          *
 231                          * imm16 = imm4:i:imm3:imm8
 232                          */
 233                         offset = ((upper & 0x000f) << 12) |
 234                                 ((upper & 0x0400) << 1) |
 235                                 ((lower & 0x7000) >> 4) | (lower & 0x00ff);
 236                         offset = (offset ^ 0x8000) - 0x8000;
 237                         offset += sym->st_value;
 238
 239                         if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS)
 240                                 offset >>= 16;
 241
 242                         upper = (u16)((upper & 0xfbf0) |
 243                                       ((offset & 0xf000) >> 12) |
 244                                       ((offset & 0x0800) >> 1));
 245                         lower = (u16)((lower & 0x8f00) |
 246                                       ((offset & 0x0700) << 4) |
 247                                       (offset & 0x00ff));
 248                         *(u16 *)loc = __opcode_to_mem_thumb16(upper);
 249                         *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
 250                         break;
 251 #endif
 252
 253                 default:
 254                         printk(KERN_ERR "%s: unknown relocation: %u\n",
 255                                module->name, ELF32_R_TYPE(rel->r_info));
 256                         return -ENOEXEC;
 257                 }
 258         }
 259         return 0;
 260 }
 261
 262 struct mod_unwind_map {
 263         const Elf_Shdr *unw_sec;
 264         const Elf_Shdr *txt_sec;
 265 };
 266
 267 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
 268         const Elf_Shdr *sechdrs, const char *name)
 269 {
 270         const Elf_Shdr *s, *se;
 271         const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 272
 273         for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
 274                 if (strcmp(name, secstrs + s->sh_name) == 0)
 275                         return s;
 276
 277         return NULL;
 278 }
 279
 280 extern void fixup_pv_table(const void *, unsigned long);
 281 extern void fixup_smp(const void *, unsigned long);
 282
 283 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 284                     struct module *mod)
 285 {
 286         const Elf_Shdr *s = NULL;
 287 #ifdef CONFIG_ARM_UNWIND
 288         const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 289         const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
 290         struct mod_unwind_map maps[ARM_SEC_MAX];
 291         int i;
 292
 293         memset(maps, 0, sizeof(maps));
 294
 295         for (s = sechdrs; s < sechdrs_end; s++) {
 296                 const char *secname = secstrs + s->sh_name;
 297
 298                 if (!(s->sh_flags & SHF_ALLOC))
 299                         continue;
 300
 301                 if (strcmp(".ARM.exidx.init.text", secname) == 0)
 302                         maps[ARM_SEC_INIT].unw_sec = s;
 303                 else if (strcmp(".ARM.exidx", secname) == 0)
 304                         maps[ARM_SEC_CORE].unw_sec = s;
 305                 else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
 306                         maps[ARM_SEC_EXIT].unw_sec = s;
 307                 else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0)
 308                         maps[ARM_SEC_UNLIKELY].unw_sec = s;
 309                 else if (strcmp(".ARM.exidx.text.hot", secname) == 0)
 310                         maps[ARM_SEC_HOT].unw_sec = s;
 311                 else if (strcmp(".init.text", secname) == 0)
 312                         maps[ARM_SEC_INIT].txt_sec = s;
 313                 else if (strcmp(".text", secname) == 0)
 314                         maps[ARM_SEC_CORE].txt_sec = s;
 315                 else if (strcmp(".exit.text", secname) == 0)
 316                         maps[ARM_SEC_EXIT].txt_sec = s;
 317                 else if (strcmp(".text.unlikely", secname) == 0)
 318                         maps[ARM_SEC_UNLIKELY].txt_sec = s;
 319                 else if (strcmp(".text.hot", secname) == 0)
 320                         maps[ARM_SEC_HOT].txt_sec = s;
 321         }
 322
 323         for (i = 0; i < ARM_SEC_MAX; i++)
 324                 if (maps[i].unw_sec && maps[i].txt_sec)
 325                         mod->arch.unwind[i] =
 326                                 unwind_table_add(maps[i].unw_sec->sh_addr,
 327                                                  maps[i].unw_sec->sh_size,
 328                                                  maps[i].txt_sec->sh_addr,
 329                                                  maps[i].txt_sec->sh_size);
 330 #endif
 331 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT
 332         s = find_mod_section(hdr, sechdrs, ".pv_table");
 333         if (s)
 334                 fixup_pv_table((void *)s->sh_addr, s->sh_size);
 335 #endif
 336         s = find_mod_section(hdr, sechdrs, ".alt.smp.init");
 337         if (s && !is_smp())
 338 #ifdef CONFIG_SMP_ON_UP
 339                 fixup_smp((void *)s->sh_addr, s->sh_size);
 340 #else
 341                 return -EINVAL;
 342 #endif
 343         return 0;
 344 }
 345
 346 void
 347 module_arch_cleanup(struct module *mod)
 348 {
 349 #ifdef CONFIG_ARM_UNWIND
 350         int i;
 351
 352         for (i = 0; i < ARM_SEC_MAX; i++)
 353                 if (mod->arch.unwind[i])
 354                         unwind_table_del(mod->arch.unwind[i]);
 355 #endif
 356 }