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/elf.h>
  17 #include <linux/vmalloc.h>
  18 #include <linux/slab.h>
  19 #include <linux/fs.h>
  20 #include <linux/string.h>
  21
  22 #include <asm/pgtable.h>
  23
  24 #ifdef CONFIG_XIP_KERNEL
  25 /*
  26  * The XIP kernel text is mapped in the module area for modules and
  27  * some other stuff to work without any indirect relocations.
  28  * MODULE_START is redefined here and not in asm/memory.h to avoid
  29  * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
  30  */
  31 extern void _etext;
  32 #undef MODULE_START
  33 #define MODULE_START    (((unsigned long)&_etext + ~PGDIR_MASK) & PGDIR_MASK)
  34 #endif
  35
  36 #ifdef CONFIG_MMU
  37 void *module_alloc(unsigned long size)
  38 {
  39         struct vm_struct *area;
  40
  41         size = PAGE_ALIGN(size);
  42         if (!size)
  43                 return NULL;
  44
  45         area = __get_vm_area(size, VM_ALLOC, MODULE_START, MODULE_END);
  46         if (!area)
  47                 return NULL;
  48
  49         return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL);
  50 }
  51 #else /* CONFIG_MMU */
  52 void *module_alloc(unsigned long size)
  53 {
  54         return size == 0 ? NULL : vmalloc(size);
  55 }
  56 #endif /* !CONFIG_MMU */
  57
  58 void module_free(struct module *module, void *region)
  59 {
  60         vfree(region);
  61 }
  62
  63 int module_frob_arch_sections(Elf_Ehdr *hdr,
  64                               Elf_Shdr *sechdrs,
  65                               char *secstrings,
  66                               struct module *mod)
  67 {
  68         return 0;
  69 }
  70
  71 int
  72 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
  73                unsigned int relindex, struct module *module)
  74 {
  75         Elf32_Shdr *symsec = sechdrs + symindex;
  76         Elf32_Shdr *relsec = sechdrs + relindex;
  77         Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
  78         Elf32_Rel *rel = (void *)relsec->sh_addr;
  79         unsigned int i;
  80
  81         for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
  82                 unsigned long loc;
  83                 Elf32_Sym *sym;
  84                 s32 offset;
  85
  86                 offset = ELF32_R_SYM(rel->r_info);
  87                 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
  88                         printk(KERN_ERR "%s: bad relocation, section %d reloc %d\n",
  89                                 module->name, relindex, i);
  90                         return -ENOEXEC;
  91                 }
  92
  93                 sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
  94
  95                 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
  96                         printk(KERN_ERR "%s: out of bounds relocation, "
  97                                 "section %d reloc %d offset %d size %d\n",
  98                                 module->name, relindex, i, rel->r_offset,
  99                                 dstsec->sh_size);
 100                         return -ENOEXEC;
 101                 }
 102
 103                 loc = dstsec->sh_addr + rel->r_offset;
 104
 105                 switch (ELF32_R_TYPE(rel->r_info)) {
 106                 case R_ARM_ABS32:
 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                         offset = (*(u32 *)loc & 0x00ffffff) << 2;
 114                         if (offset & 0x02000000)
 115                                 offset -= 0x04000000;
 116
 117                         offset += sym->st_value - loc;
 118                         if (offset & 3 ||
 119                             offset <= (s32)0xfe000000 ||
 120                             offset >= (s32)0x02000000) {
 121                                 printk(KERN_ERR
 122                                        "%s: relocation out of range, section "
 123                                        "%d reloc %d sym '%s'\n", module->name,
 124                                        relindex, i, strtab + sym->st_name);
 125                                 return -ENOEXEC;
 126                         }
 127
 128                         offset >>= 2;
 129
 130                         *(u32 *)loc &= 0xff000000;
 131                         *(u32 *)loc |= offset & 0x00ffffff;
 132                         break;
 133
 134                 default:
 135                         printk(KERN_ERR "%s: unknown relocation: %u\n",
 136                                module->name, ELF32_R_TYPE(rel->r_info));
 137                         return -ENOEXEC;
 138                 }
 139         }
 140         return 0;
 141 }
 142
 143 int
 144 apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
 145                    unsigned int symindex, unsigned int relsec, struct module *module)
 146 {
 147         printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
 148                module->name);
 149         return -ENOEXEC;
 150 }
 151
 152 int
 153 module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 154                 struct module *module)
 155 {
 156         return 0;
 157 }
 158
 159 void
 160 module_arch_cleanup(struct module *mod)
 161 {
 162 }