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)_exiprom + ~PMD_MASK) & PMD_MASK)
  38 #endif
  39
  40 #ifdef CONFIG_MMU
  41 void *module_alloc(unsigned long size)
  42 {
  43         gfp_t gfp_mask = GFP_KERNEL;
  44         void *p;
  45
  46         /* Silence the initial allocation */
  47         if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS))
  48                 gfp_mask |= __GFP_NOWARN;
  49
  50         p = __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
  51                                 gfp_mask, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
  52                                 __builtin_return_address(0));
  53         if (!IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || p)
  54                 return p;
  55         return __vmalloc_node_range(size, 1,  VMALLOC_START, VMALLOC_END,
  56                                 GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
  57                                 __builtin_return_address(0));
  58 }
  59 #endif
  60
  61 int
  62 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
  63                unsigned int relindex, struct module *module)
  64 {
  65         Elf32_Shdr *symsec = sechdrs + symindex;
  66         Elf32_Shdr *relsec = sechdrs + relindex;
  67         Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
  68         Elf32_Rel *rel = (void *)relsec->sh_addr;
  69         unsigned int i;
  70
  71         for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
  72                 unsigned long loc;
  73                 Elf32_Sym *sym;
  74                 const char *symname;
  75                 s32 offset;
  76                 u32 tmp;
  77 #ifdef CONFIG_THUMB2_KERNEL
  78                 u32 upper, lower, sign, j1, j2;
  79 #endif
  80
  81                 offset = ELF32_R_SYM(rel->r_info);
  82                 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
  83                         pr_err("%s: section %u reloc %u: bad relocation sym offset\n",
  84                                 module->name, relindex, i);
  85                         return -ENOEXEC;
  86                 }
  87
  88                 sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
  89                 symname = strtab + sym->st_name;
  90
  91                 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
  92                         pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n",
  93                                module->name, relindex, i, symname,
  94                                rel->r_offset, dstsec->sh_size);
  95                         return -ENOEXEC;
  96                 }
  97
  98                 loc = dstsec->sh_addr + rel->r_offset;
  99
 100                 switch (ELF32_R_TYPE(rel->r_info)) {
 101                 case R_ARM_NONE:
 102                         /* ignore */
 103                         break;
 104
 105                 case R_ARM_ABS32:
 106                 case R_ARM_TARGET1:
 107                         *(u32 *)loc += sym->st_value;
 108                         break;
 109
 110                 case R_ARM_PC24:
 111                 case R_ARM_CALL:
 112                 case R_ARM_JUMP24:
 113                         if (sym->st_value & 3) {
 114                                 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (ARM -> Thumb)\n",
 115                                        module->name, relindex, i, symname);
 116                                 return -ENOEXEC;
 117                         }
 118
 119                         offset = __mem_to_opcode_arm(*(u32 *)loc);
 120                         offset = (offset & 0x00ffffff) << 2;
 121                         if (offset & 0x02000000)
 122                                 offset -= 0x04000000;
 123
 124                         offset += sym->st_value - loc;
 125
 126                         /*
 127                          * Route through a PLT entry if 'offset' exceeds the
 128                          * supported range. Note that 'offset + loc + 8'
 129                          * contains the absolute jump target, i.e.,
 130                          * @sym + addend, corrected for the +8 PC bias.
 131                          */
 132                         if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) &&
 133                             (offset <= (s32)0xfe000000 ||
 134                              offset >= (s32)0x02000000))
 135                                 offset = get_module_plt(module, loc,
 136                                                         offset + loc + 8)
 137                                          - loc - 8;
 138
 139                         if (offset <= (s32)0xfe000000 ||
 140                             offset >= (s32)0x02000000) {
 141                                 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
 142                                        module->name, relindex, i, symname,
 143                                        ELF32_R_TYPE(rel->r_info), loc,
 144                                        sym->st_value);
 145                                 return -ENOEXEC;
 146                         }
 147
 148                         offset >>= 2;
 149                         offset &= 0x00ffffff;
 150
 151                         *(u32 *)loc &= __opcode_to_mem_arm(0xff000000);
 152                         *(u32 *)loc |= __opcode_to_mem_arm(offset);
 153                         break;
 154
 155                case R_ARM_V4BX:
 156                        /* Preserve Rm and the condition code. Alter
 157                         * other bits to re-code instruction as
 158                         * MOV PC,Rm.
 159                         */
 160                        *(u32 *)loc &= __opcode_to_mem_arm(0xf000000f);
 161                        *(u32 *)loc |= __opcode_to_mem_arm(0x01a0f000);
 162                        break;
 163
 164                 case R_ARM_PREL31:
 165                         offset = (*(s32 *)loc << 1) >> 1; /* sign extend */
 166                         offset += sym->st_value - loc;
 167                         if (offset >= 0x40000000 || offset < -0x40000000) {
 168                                 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
 169                                        module->name, relindex, i, symname,
 170                                        ELF32_R_TYPE(rel->r_info), loc,
 171                                        sym->st_value);
 172                                 return -ENOEXEC;
 173                         }
 174                         *(u32 *)loc &= 0x80000000;
 175                         *(u32 *)loc |= offset & 0x7fffffff;
 176                         break;
 177
 178                 case R_ARM_MOVW_ABS_NC:
 179                 case R_ARM_MOVT_ABS:
 180                         offset = tmp = __mem_to_opcode_arm(*(u32 *)loc);
 181                         offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
 182                         offset = (offset ^ 0x8000) - 0x8000;
 183
 184                         offset += sym->st_value;
 185                         if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS)
 186                                 offset >>= 16;
 187
 188                         tmp &= 0xfff0f000;
 189                         tmp |= ((offset & 0xf000) << 4) |
 190                                 (offset & 0x0fff);
 191
 192                         *(u32 *)loc = __opcode_to_mem_arm(tmp);
 193                         break;
 194
 195 #ifdef CONFIG_THUMB2_KERNEL
 196                 case R_ARM_THM_CALL:
 197                 case R_ARM_THM_JUMP24:
 198                         /*
 199                          * For function symbols, only Thumb addresses are
 200                          * allowed (no interworking).
 201                          *
 202                          * For non-function symbols, the destination
 203                          * has no specific ARM/Thumb disposition, so
 204                          * the branch is resolved under the assumption
 205                          * that interworking is not required.
 206                          */
 207                         if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
 208                             !(sym->st_value & 1)) {
 209                                 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (Thumb -> ARM)\n",
 210                                        module->name, relindex, i, symname);
 211                                 return -ENOEXEC;
 212                         }
 213
 214                         upper = __mem_to_opcode_thumb16(*(u16 *)loc);
 215                         lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
 216
 217                         /*
 218                          * 25 bit signed address range (Thumb-2 BL and B.W
 219                          * instructions):
 220                          *   S:I1:I2:imm10:imm11:0
 221                          * where:
 222                          *   S     = upper[10]   = offset[24]
 223                          *   I1    = ~(J1 ^ S)   = offset[23]
 224                          *   I2    = ~(J2 ^ S)   = offset[22]
 225                          *   imm10 = upper[9:0]  = offset[21:12]
 226                          *   imm11 = lower[10:0] = offset[11:1]
 227                          *   J1    = lower[13]
 228                          *   J2    = lower[11]
 229                          */
 230                         sign = (upper >> 10) & 1;
 231                         j1 = (lower >> 13) & 1;
 232                         j2 = (lower >> 11) & 1;
 233                         offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
 234                                 ((~(j2 ^ sign) & 1) << 22) |
 235                                 ((upper & 0x03ff) << 12) |
 236                                 ((lower & 0x07ff) << 1);
 237                         if (offset & 0x01000000)
 238                                 offset -= 0x02000000;
 239                         offset += sym->st_value - loc;
 240
 241                         /*
 242                          * Route through a PLT entry if 'offset' exceeds the
 243                          * supported range.
 244                          */
 245                         if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) &&
 246                             (offset <= (s32)0xff000000 ||
 247                              offset >= (s32)0x01000000))
 248                                 offset = get_module_plt(module, loc,
 249                                                         offset + loc + 4)
 250                                          - loc - 4;
 251
 252                         if (offset <= (s32)0xff000000 ||
 253                             offset >= (s32)0x01000000) {
 254                                 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
 255                                        module->name, relindex, i, symname,
 256                                        ELF32_R_TYPE(rel->r_info), loc,
 257                                        sym->st_value);
 258                                 return -ENOEXEC;
 259                         }
 260
 261                         sign = (offset >> 24) & 1;
 262                         j1 = sign ^ (~(offset >> 23) & 1);
 263                         j2 = sign ^ (~(offset >> 22) & 1);
 264                         upper = (u16)((upper & 0xf800) | (sign << 10) |
 265                                             ((offset >> 12) & 0x03ff));
 266                         lower = (u16)((lower & 0xd000) |
 267                                       (j1 << 13) | (j2 << 11) |
 268                                       ((offset >> 1) & 0x07ff));
 269
 270                         *(u16 *)loc = __opcode_to_mem_thumb16(upper);
 271                         *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
 272                         break;
 273
 274                 case R_ARM_THM_MOVW_ABS_NC:
 275                 case R_ARM_THM_MOVT_ABS:
 276                         upper = __mem_to_opcode_thumb16(*(u16 *)loc);
 277                         lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
 278
 279                         /*
 280                          * MOVT/MOVW instructions encoding in Thumb-2:
 281                          *
 282                          * i    = upper[10]
 283                          * imm4 = upper[3:0]
 284                          * imm3 = lower[14:12]
 285                          * imm8 = lower[7:0]
 286                          *
 287                          * imm16 = imm4:i:imm3:imm8
 288                          */
 289                         offset = ((upper & 0x000f) << 12) |
 290                                 ((upper & 0x0400) << 1) |
 291                                 ((lower & 0x7000) >> 4) | (lower & 0x00ff);
 292                         offset = (offset ^ 0x8000) - 0x8000;
 293                         offset += sym->st_value;
 294
 295                         if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS)
 296                                 offset >>= 16;
 297
 298                         upper = (u16)((upper & 0xfbf0) |
 299                                       ((offset & 0xf000) >> 12) |
 300                                       ((offset & 0x0800) >> 1));
 301                         lower = (u16)((lower & 0x8f00) |
 302                                       ((offset & 0x0700) << 4) |
 303                                       (offset & 0x00ff));
 304                         *(u16 *)loc = __opcode_to_mem_thumb16(upper);
 305                         *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
 306                         break;
 307 #endif
 308
 309                 default:
 310                         pr_err("%s: unknown relocation: %u\n",
 311                                module->name, ELF32_R_TYPE(rel->r_info));
 312                         return -ENOEXEC;
 313                 }
 314         }
 315         return 0;
 316 }
 317
 318 struct mod_unwind_map {
 319         const Elf_Shdr *unw_sec;
 320         const Elf_Shdr *txt_sec;
 321 };
 322
 323 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
 324         const Elf_Shdr *sechdrs, const char *name)
 325 {
 326         const Elf_Shdr *s, *se;
 327         const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 328
 329         for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
 330                 if (strcmp(name, secstrs + s->sh_name) == 0)
 331                         return s;
 332
 333         return NULL;
 334 }
 335
 336 extern void fixup_pv_table(const void *, unsigned long);
 337 extern void fixup_smp(const void *, unsigned long);
 338
 339 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 340                     struct module *mod)
 341 {
 342         const Elf_Shdr *s = NULL;
 343 #ifdef CONFIG_ARM_UNWIND
 344         const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 345         const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
 346         struct mod_unwind_map maps[ARM_SEC_MAX];
 347         int i;
 348
 349         memset(maps, 0, sizeof(maps));
 350
 351         for (s = sechdrs; s < sechdrs_end; s++) {
 352                 const char *secname = secstrs + s->sh_name;
 353
 354                 if (!(s->sh_flags & SHF_ALLOC))
 355                         continue;
 356
 357                 if (strcmp(".ARM.exidx.init.text", secname) == 0)
 358                         maps[ARM_SEC_INIT].unw_sec = s;
 359                 else if (strcmp(".ARM.exidx", secname) == 0)
 360                         maps[ARM_SEC_CORE].unw_sec = s;
 361                 else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
 362                         maps[ARM_SEC_EXIT].unw_sec = s;
 363                 else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0)
 364                         maps[ARM_SEC_UNLIKELY].unw_sec = s;
 365                 else if (strcmp(".ARM.exidx.text.hot", secname) == 0)
 366                         maps[ARM_SEC_HOT].unw_sec = s;
 367                 else if (strcmp(".init.text", secname) == 0)
 368                         maps[ARM_SEC_INIT].txt_sec = s;
 369                 else if (strcmp(".text", secname) == 0)
 370                         maps[ARM_SEC_CORE].txt_sec = s;
 371                 else if (strcmp(".exit.text", secname) == 0)
 372                         maps[ARM_SEC_EXIT].txt_sec = s;
 373                 else if (strcmp(".text.unlikely", secname) == 0)
 374                         maps[ARM_SEC_UNLIKELY].txt_sec = s;
 375                 else if (strcmp(".text.hot", secname) == 0)
 376                         maps[ARM_SEC_HOT].txt_sec = s;
 377         }
 378
 379         for (i = 0; i < ARM_SEC_MAX; i++)
 380                 if (maps[i].unw_sec && maps[i].txt_sec)
 381                         mod->arch.unwind[i] =
 382                                 unwind_table_add(maps[i].unw_sec->sh_addr,
 383                                                  maps[i].unw_sec->sh_size,
 384                                                  maps[i].txt_sec->sh_addr,
 385                                                  maps[i].txt_sec->sh_size);
 386 #endif
 387 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT
 388         s = find_mod_section(hdr, sechdrs, ".pv_table");
 389         if (s)
 390                 fixup_pv_table((void *)s->sh_addr, s->sh_size);
 391 #endif
 392         s = find_mod_section(hdr, sechdrs, ".alt.smp.init");
 393         if (s && !is_smp())
 394 #ifdef CONFIG_SMP_ON_UP
 395                 fixup_smp((void *)s->sh_addr, s->sh_size);
 396 #else
 397                 return -EINVAL;
 398 #endif
 399         return 0;
 400 }
 401
 402 void
 403 module_arch_cleanup(struct module *mod)
 404 {
 405 #ifdef CONFIG_ARM_UNWIND
 406         int i;
 407
 408         for (i = 0; i < ARM_SEC_MAX; i++)
 409                 if (mod->arch.unwind[i])
 410                         unwind_table_del(mod->arch.unwind[i]);
 411 #endif
 412 }