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/slab.h>
  20 #include <linux/fs.h>
  21 #include <linux/string.h>
  22
  23 #include <asm/pgtable.h>
  24 #include <asm/sections.h>
  25 #include <asm/unwind.h>
  26
  27 #ifdef CONFIG_XIP_KERNEL
  28 /*
  29  * The XIP kernel text is mapped in the module area for modules and
  30  * some other stuff to work without any indirect relocations.
  31  * MODULES_VADDR is redefined here and not in asm/memory.h to avoid
  32  * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
  33  */
  34 #undef MODULES_VADDR
  35 #define MODULES_VADDR   (((unsigned long)_etext + ~PGDIR_MASK) & PGDIR_MASK)
  36 #endif
  37
  38 #ifdef CONFIG_MMU
  39 void *module_alloc(unsigned long size)
  40 {
  41         struct vm_struct *area;
  42
  43         size = PAGE_ALIGN(size);
  44         if (!size)
  45                 return NULL;
  46
  47         area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END);
  48         if (!area)
  49                 return NULL;
  50
  51         return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL_EXEC);
  52 }
  53 #else /* CONFIG_MMU */
  54 void *module_alloc(unsigned long size)
  55 {
  56         return size == 0 ? NULL : vmalloc(size);
  57 }
  58 #endif /* !CONFIG_MMU */
  59
  60 void module_free(struct module *module, void *region)
  61 {
  62         vfree(region);
  63 }
  64
  65 int module_frob_arch_sections(Elf_Ehdr *hdr,
  66                               Elf_Shdr *sechdrs,
  67                               char *secstrings,
  68                               struct module *mod)
  69 {
  70 #ifdef CONFIG_ARM_UNWIND
  71         Elf_Shdr *s, *sechdrs_end = sechdrs + hdr->e_shnum;
  72
  73         for (s = sechdrs; s < sechdrs_end; s++) {
  74                 if (strcmp(".ARM.exidx.init.text", secstrings + s->sh_name) == 0)
  75                         mod->arch.unw_sec_init = s;
  76                 else if (strcmp(".ARM.exidx.devinit.text", secstrings + s->sh_name) == 0)
  77                         mod->arch.unw_sec_devinit = s;
  78                 else if (strcmp(".ARM.exidx", secstrings + s->sh_name) == 0)
  79                         mod->arch.unw_sec_core = s;
  80                 else if (strcmp(".init.text", secstrings + s->sh_name) == 0)
  81                         mod->arch.sec_init_text = s;
  82                 else if (strcmp(".devinit.text", secstrings + s->sh_name) == 0)
  83                         mod->arch.sec_devinit_text = s;
  84                 else if (strcmp(".text", secstrings + s->sh_name) == 0)
  85                         mod->arch.sec_core_text = s;
  86         }
  87 #endif
  88         return 0;
  89 }
  90
  91 int
  92 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
  93                unsigned int relindex, struct module *module)
  94 {
  95         Elf32_Shdr *symsec = sechdrs + symindex;
  96         Elf32_Shdr *relsec = sechdrs + relindex;
  97         Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
  98         Elf32_Rel *rel = (void *)relsec->sh_addr;
  99         unsigned int i;
 100
 101         for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
 102                 unsigned long loc;
 103                 Elf32_Sym *sym;
 104                 s32 offset;
 105
 106                 offset = ELF32_R_SYM(rel->r_info);
 107                 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
 108                         printk(KERN_ERR "%s: bad relocation, section %d reloc %d\n",
 109                                 module->name, relindex, i);
 110                         return -ENOEXEC;
 111                 }
 112
 113                 sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
 114
 115                 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
 116                         printk(KERN_ERR "%s: out of bounds relocation, "
 117                                 "section %d reloc %d offset %d size %d\n",
 118                                 module->name, relindex, i, rel->r_offset,
 119                                 dstsec->sh_size);
 120                         return -ENOEXEC;
 121                 }
 122
 123                 loc = dstsec->sh_addr + rel->r_offset;
 124
 125                 switch (ELF32_R_TYPE(rel->r_info)) {
 126                 case R_ARM_NONE:
 127                         /* ignore */
 128                         break;
 129
 130                 case R_ARM_ABS32:
 131                         *(u32 *)loc += sym->st_value;
 132                         break;
 133
 134                 case R_ARM_PC24:
 135                 case R_ARM_CALL:
 136                 case R_ARM_JUMP24:
 137                         offset = (*(u32 *)loc & 0x00ffffff) << 2;
 138                         if (offset & 0x02000000)
 139                                 offset -= 0x04000000;
 140
 141                         offset += sym->st_value - loc;
 142                         if (offset & 3 ||
 143                             offset <= (s32)0xfe000000 ||
 144                             offset >= (s32)0x02000000) {
 145                                 printk(KERN_ERR
 146                                        "%s: relocation out of range, section "
 147                                        "%d reloc %d sym '%s'\n", module->name,
 148                                        relindex, i, strtab + sym->st_name);
 149                                 return -ENOEXEC;
 150                         }
 151
 152                         offset >>= 2;
 153
 154                         *(u32 *)loc &= 0xff000000;
 155                         *(u32 *)loc |= offset & 0x00ffffff;
 156                         break;
 157
 158                case R_ARM_V4BX:
 159                        /* Preserve Rm and the condition code. Alter
 160                         * other bits to re-code instruction as
 161                         * MOV PC,Rm.
 162                         */
 163                        *(u32 *)loc &= 0xf000000f;
 164                        *(u32 *)loc |= 0x01a0f000;
 165                        break;
 166
 167                 case R_ARM_PREL31:
 168                         offset = *(u32 *)loc + sym->st_value - loc;
 169                         *(u32 *)loc = offset & 0x7fffffff;
 170                         break;
 171
 172                 case R_ARM_MOVW_ABS_NC:
 173                 case R_ARM_MOVT_ABS:
 174                         offset = *(u32 *)loc;
 175                         offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
 176                         offset = (offset ^ 0x8000) - 0x8000;
 177
 178                         offset += sym->st_value;
 179                         if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS)
 180                                 offset >>= 16;
 181
 182                         *(u32 *)loc &= 0xfff0f000;
 183                         *(u32 *)loc |= ((offset & 0xf000) << 4) |
 184                                         (offset & 0x0fff);
 185                         break;
 186
 187                 default:
 188                         printk(KERN_ERR "%s: unknown relocation: %u\n",
 189                                module->name, ELF32_R_TYPE(rel->r_info));
 190                         return -ENOEXEC;
 191                 }
 192         }
 193         return 0;
 194 }
 195
 196 int
 197 apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
 198                    unsigned int symindex, unsigned int relsec, struct module *module)
 199 {
 200         printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
 201                module->name);
 202         return -ENOEXEC;
 203 }
 204
 205 #ifdef CONFIG_ARM_UNWIND
 206 static void register_unwind_tables(struct module *mod)
 207 {
 208         if (mod->arch.unw_sec_init && mod->arch.sec_init_text)
 209                 mod->arch.unwind_init =
 210                         unwind_table_add(mod->arch.unw_sec_init->sh_addr,
 211                                          mod->arch.unw_sec_init->sh_size,
 212                                          mod->arch.sec_init_text->sh_addr,
 213                                          mod->arch.sec_init_text->sh_size);
 214         if (mod->arch.unw_sec_devinit && mod->arch.sec_devinit_text)
 215                 mod->arch.unwind_devinit =
 216                         unwind_table_add(mod->arch.unw_sec_devinit->sh_addr,
 217                                          mod->arch.unw_sec_devinit->sh_size,
 218                                          mod->arch.sec_devinit_text->sh_addr,
 219                                          mod->arch.sec_devinit_text->sh_size);
 220         if (mod->arch.unw_sec_core && mod->arch.sec_core_text)
 221                 mod->arch.unwind_core =
 222                         unwind_table_add(mod->arch.unw_sec_core->sh_addr,
 223                                          mod->arch.unw_sec_core->sh_size,
 224                                          mod->arch.sec_core_text->sh_addr,
 225                                          mod->arch.sec_core_text->sh_size);
 226 }
 227
 228 static void unregister_unwind_tables(struct module *mod)
 229 {
 230         unwind_table_del(mod->arch.unwind_init);
 231         unwind_table_del(mod->arch.unwind_devinit);
 232         unwind_table_del(mod->arch.unwind_core);
 233 }
 234 #else
 235 static inline void register_unwind_tables(struct module *mod) { }
 236 static inline void unregister_unwind_tables(struct module *mod) { }
 237 #endif
 238
 239 int
 240 module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 241                 struct module *module)
 242 {
 243         register_unwind_tables(module);
 244         return 0;
 245 }
 246
 247 void
 248 module_arch_cleanup(struct module *mod)
 249 {
 250         unregister_unwind_tables(mod);
 251 }