kernel/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, 0, 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                         if (sym->st_value & 3) {
 102                                 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (ARM -> Thumb)\n",
 103                                        module->name, relindex, i, symname);
 104                                 return -ENOEXEC;
 105                         }
 106
 107                         offset = __mem_to_opcode_arm(*(u32 *)loc);
 108                         offset = (offset & 0x00ffffff) << 2;
 109                         if (offset & 0x02000000)
 110                                 offset -= 0x04000000;
 111
 112                         offset += sym->st_value - loc;
 113                         if (offset <= (s32)0xfe000000 ||
 114                             offset >= (s32)0x02000000) {
 115                                 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
 116                                        module->name, relindex, i, symname,
 117                                        ELF32_R_TYPE(rel->r_info), loc,
 118                                        sym->st_value);
 119                                 return -ENOEXEC;
 120                         }
 121
 122                         offset >>= 2;
 123                         offset &= 0x00ffffff;
 124
 125                         *(u32 *)loc &= __opcode_to_mem_arm(0xff000000);
 126                         *(u32 *)loc |= __opcode_to_mem_arm(offset);
 127                         break;
 128
 129                case R_ARM_V4BX:
 130                        /* Preserve Rm and the condition code. Alter
 131                         * other bits to re-code instruction as
 132                         * MOV PC,Rm.
 133                         */
 134                        *(u32 *)loc &= __opcode_to_mem_arm(0xf000000f);
 135                        *(u32 *)loc |= __opcode_to_mem_arm(0x01a0f000);
 136                        break;
 137
 138                 case R_ARM_PREL31:
 139                         offset = *(u32 *)loc + sym->st_value - loc;
 140                         *(u32 *)loc = offset & 0x7fffffff;
 141                         break;
 142
 143                 case R_ARM_MOVW_ABS_NC:
 144                 case R_ARM_MOVT_ABS:
 145                         offset = tmp = __mem_to_opcode_arm(*(u32 *)loc);
 146                         offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
 147                         offset = (offset ^ 0x8000) - 0x8000;
 148
 149                         offset += sym->st_value;
 150                         if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS)
 151                                 offset >>= 16;
 152
 153                         tmp &= 0xfff0f000;
 154                         tmp |= ((offset & 0xf000) << 4) |
 155                                 (offset & 0x0fff);
 156
 157                         *(u32 *)loc = __opcode_to_mem_arm(tmp);
 158                         break;
 159
 160 #ifdef CONFIG_THUMB2_KERNEL
 161                 case R_ARM_THM_CALL:
 162                 case R_ARM_THM_JUMP24:
 163                         /*
 164                          * For function symbols, only Thumb addresses are
 165                          * allowed (no interworking).
 166                          *
 167                          * For non-function symbols, the destination
 168                          * has no specific ARM/Thumb disposition, so
 169                          * the branch is resolved under the assumption
 170                          * that interworking is not required.
 171                          */
 172                         if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
 173                             !(sym->st_value & 1)) {
 174                                 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (Thumb -> ARM)\n",
 175                                        module->name, relindex, i, symname);
 176                                 return -ENOEXEC;
 177                         }
 178
 179                         upper = __mem_to_opcode_thumb16(*(u16 *)loc);
 180                         lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
 181
 182                         /*
 183                          * 25 bit signed address range (Thumb-2 BL and B.W
 184                          * instructions):
 185                          *   S:I1:I2:imm10:imm11:0
 186                          * where:
 187                          *   S     = upper[10]   = offset[24]
 188                          *   I1    = ~(J1 ^ S)   = offset[23]
 189                          *   I2    = ~(J2 ^ S)   = offset[22]
 190                          *   imm10 = upper[9:0]  = offset[21:12]
 191                          *   imm11 = lower[10:0] = offset[11:1]
 192                          *   J1    = lower[13]
 193                          *   J2    = lower[11]
 194                          */
 195                         sign = (upper >> 10) & 1;
 196                         j1 = (lower >> 13) & 1;
 197                         j2 = (lower >> 11) & 1;
 198                         offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
 199                                 ((~(j2 ^ sign) & 1) << 22) |
 200                                 ((upper & 0x03ff) << 12) |
 201                                 ((lower & 0x07ff) << 1);
 202                         if (offset & 0x01000000)
 203                                 offset -= 0x02000000;
 204                         offset += sym->st_value - loc;
 205
 206                         if (offset <= (s32)0xff000000 ||
 207                             offset >= (s32)0x01000000) {
 208                                 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
 209                                        module->name, relindex, i, symname,
 210                                        ELF32_R_TYPE(rel->r_info), loc,
 211                                        sym->st_value);
 212                                 return -ENOEXEC;
 213                         }
 214
 215                         sign = (offset >> 24) & 1;
 216                         j1 = sign ^ (~(offset >> 23) & 1);
 217                         j2 = sign ^ (~(offset >> 22) & 1);
 218                         upper = (u16)((upper & 0xf800) | (sign << 10) |
 219                                             ((offset >> 12) & 0x03ff));
 220                         lower = (u16)((lower & 0xd000) |
 221                                       (j1 << 13) | (j2 << 11) |
 222                                       ((offset >> 1) & 0x07ff));
 223
 224                         *(u16 *)loc = __opcode_to_mem_thumb16(upper);
 225                         *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
 226                         break;
 227
 228                 case R_ARM_THM_MOVW_ABS_NC:
 229                 case R_ARM_THM_MOVT_ABS:
 230                         upper = __mem_to_opcode_thumb16(*(u16 *)loc);
 231                         lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
 232
 233                         /*
 234                          * MOVT/MOVW instructions encoding in Thumb-2:
 235                          *
 236                          * i    = upper[10]
 237                          * imm4 = upper[3:0]
 238                          * imm3 = lower[14:12]
 239                          * imm8 = lower[7:0]
 240                          *
 241                          * imm16 = imm4:i:imm3:imm8
 242                          */
 243                         offset = ((upper & 0x000f) << 12) |
 244                                 ((upper & 0x0400) << 1) |
 245                                 ((lower & 0x7000) >> 4) | (lower & 0x00ff);
 246                         offset = (offset ^ 0x8000) - 0x8000;
 247                         offset += sym->st_value;
 248
 249                         if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS)
 250                                 offset >>= 16;
 251
 252                         upper = (u16)((upper & 0xfbf0) |
 253                                       ((offset & 0xf000) >> 12) |
 254                                       ((offset & 0x0800) >> 1));
 255                         lower = (u16)((lower & 0x8f00) |
 256                                       ((offset & 0x0700) << 4) |
 257                                       (offset & 0x00ff));
 258                         *(u16 *)loc = __opcode_to_mem_thumb16(upper);
 259                         *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
 260                         break;
 261 #endif
 262
 263                 default:
 264                         pr_err("%s: unknown relocation: %u\n",
 265                                module->name, ELF32_R_TYPE(rel->r_info));
 266                         return -ENOEXEC;
 267                 }
 268         }
 269         return 0;
 270 }
 271
 272 struct mod_unwind_map {
 273         const Elf_Shdr *unw_sec;
 274         const Elf_Shdr *txt_sec;
 275 };
 276
 277 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
 278         const Elf_Shdr *sechdrs, const char *name)
 279 {
 280         const Elf_Shdr *s, *se;
 281         const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 282
 283         for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
 284                 if (strcmp(name, secstrs + s->sh_name) == 0)
 285                         return s;
 286
 287         return NULL;
 288 }
 289
 290 extern void fixup_pv_table(const void *, unsigned long);
 291 extern void fixup_smp(const void *, unsigned long);
 292
 293 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 294                     struct module *mod)
 295 {
 296         const Elf_Shdr *s = NULL;
 297 #ifdef CONFIG_ARM_UNWIND
 298         const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 299         const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
 300         struct mod_unwind_map maps[ARM_SEC_MAX];
 301         int i;
 302
 303         memset(maps, 0, sizeof(maps));
 304
 305         for (s = sechdrs; s < sechdrs_end; s++) {
 306                 const char *secname = secstrs + s->sh_name;
 307
 308                 if (!(s->sh_flags & SHF_ALLOC))
 309                         continue;
 310
 311                 if (strcmp(".ARM.exidx.init.text", secname) == 0)
 312                         maps[ARM_SEC_INIT].unw_sec = s;
 313                 else if (strcmp(".ARM.exidx", secname) == 0)
 314                         maps[ARM_SEC_CORE].unw_sec = s;
 315                 else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
 316                         maps[ARM_SEC_EXIT].unw_sec = s;
 317                 else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0)
 318                         maps[ARM_SEC_UNLIKELY].unw_sec = s;
 319                 else if (strcmp(".ARM.exidx.text.hot", secname) == 0)
 320                         maps[ARM_SEC_HOT].unw_sec = s;
 321                 else if (strcmp(".init.text", secname) == 0)
 322                         maps[ARM_SEC_INIT].txt_sec = s;
 323                 else if (strcmp(".text", secname) == 0)
 324                         maps[ARM_SEC_CORE].txt_sec = s;
 325                 else if (strcmp(".exit.text", secname) == 0)
 326                         maps[ARM_SEC_EXIT].txt_sec = s;
 327                 else if (strcmp(".text.unlikely", secname) == 0)
 328                         maps[ARM_SEC_UNLIKELY].txt_sec = s;
 329                 else if (strcmp(".text.hot", secname) == 0)
 330                         maps[ARM_SEC_HOT].txt_sec = s;
 331         }
 332
 333         for (i = 0; i < ARM_SEC_MAX; i++)
 334                 if (maps[i].unw_sec && maps[i].txt_sec)
 335                         mod->arch.unwind[i] =
 336                                 unwind_table_add(maps[i].unw_sec->sh_addr,
 337                                                  maps[i].unw_sec->sh_size,
 338                                                  maps[i].txt_sec->sh_addr,
 339                                                  maps[i].txt_sec->sh_size);
 340 #endif
 341 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT
 342         s = find_mod_section(hdr, sechdrs, ".pv_table");
 343         if (s)
 344                 fixup_pv_table((void *)s->sh_addr, s->sh_size);
 345 #endif
 346         s = find_mod_section(hdr, sechdrs, ".alt.smp.init");
 347         if (s && !is_smp())
 348 #ifdef CONFIG_SMP_ON_UP
 349                 fixup_smp((void *)s->sh_addr, s->sh_size);
 350 #else
 351                 return -EINVAL;
 352 #endif
 353         return 0;
 354 }
 355
 356 void
 357 module_arch_cleanup(struct module *mod)
 358 {
 359 #ifdef CONFIG_ARM_UNWIND
 360         int i;
 361
 362         for (i = 0; i < ARM_SEC_MAX; i++)
 363                 if (mod->arch.unwind[i])
 364                         unwind_table_del(mod->arch.unwind[i]);
 365 #endif
 366 }