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