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