arch/arm/kernel/module.c

   1 /*
   2  *  linux/arch/arm/kernel/module.c
   3  *
   4  *  Copyright (C) 2002 Russell King.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Module allocation method suggested by Andi Kleen.
  11  */
  12 #include <linux/module.h>
  13 #include <linux/moduleloader.h>
  14 #include <linux/kernel.h>
  15 #include <linux/elf.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/slab.h>
  18 #include <linux/fs.h>
  19 #include <linux/string.h>
  20
  21 #include <asm/pgtable.h>
  22
  23 #ifdef CONFIG_XIP_KERNEL
  24 /*
  25  * The XIP kernel text is mapped in the module area for modules and
  26  * some other stuff to work without any indirect relocations.
  27  * MODULE_START is redefined here and not in asm/memory.h to avoid
  28  * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
  29  */
  30 extern void _etext;
  31 #undef MODULE_START
  32 #define MODULE_START    (((unsigned long)&_etext + ~PGDIR_MASK) & PGDIR_MASK)
  33 #endif
  34
  35 void *module_alloc(unsigned long size)
  36 {
  37         struct vm_struct *area;
  38
  39         size = PAGE_ALIGN(size);
  40         if (!size)
  41                 return NULL;
  42
  43         area = __get_vm_area(size, VM_ALLOC, MODULE_START, MODULE_END);
  44         if (!area)
  45                 return NULL;
  46
  47         return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL);
  48 }
  49
  50 void module_free(struct module *module, void *region)
  51 {
  52         vfree(region);
  53 }
  54
  55 int module_frob_arch_sections(Elf_Ehdr *hdr,
  56                               Elf_Shdr *sechdrs,
  57                               char *secstrings,
  58                               struct module *mod)
  59 {
  60         return 0;
  61 }
  62
  63 int
  64 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
  65                unsigned int relindex, struct module *module)
  66 {
  67         Elf32_Shdr *symsec = sechdrs + symindex;
  68         Elf32_Shdr *relsec = sechdrs + relindex;
  69         Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
  70         Elf32_Rel *rel = (void *)relsec->sh_addr;
  71         unsigned int i;
  72
  73         for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
  74                 unsigned long loc;
  75                 Elf32_Sym *sym;
  76                 s32 offset;
  77
  78                 offset = ELF32_R_SYM(rel->r_info);
  79                 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
  80                         printk(KERN_ERR "%s: bad relocation, section %d reloc %d\n",
  81                                 module->name, relindex, i);
  82                         return -ENOEXEC;
  83                 }
  84
  85                 sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
  86
  87                 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
  88                         printk(KERN_ERR "%s: out of bounds relocation, "
  89                                 "section %d reloc %d offset %d size %d\n",
  90                                 module->name, relindex, i, rel->r_offset,
  91                                 dstsec->sh_size);
  92                         return -ENOEXEC;
  93                 }
  94
  95                 loc = dstsec->sh_addr + rel->r_offset;
  96
  97                 switch (ELF32_R_TYPE(rel->r_info)) {
  98                 case R_ARM_ABS32:
  99                         *(u32 *)loc += sym->st_value;
 100                         break;
 101
 102                 case R_ARM_PC24:
 103                 case R_ARM_CALL:
 104                 case R_ARM_JUMP24:
 105                         offset = (*(u32 *)loc & 0x00ffffff) << 2;
 106                         if (offset & 0x02000000)
 107                                 offset -= 0x04000000;
 108
 109                         offset += sym->st_value - loc;
 110                         if (offset & 3 ||
 111                             offset <= (s32)0xfc000000 ||
 112                             offset >= (s32)0x04000000) {
 113                                 printk(KERN_ERR
 114                                        "%s: relocation out of range, section "
 115                                        "%d reloc %d sym '%s'\n", module->name,
 116                                        relindex, i, strtab + sym->st_name);
 117                                 return -ENOEXEC;
 118                         }
 119
 120                         offset >>= 2;
 121
 122                         *(u32 *)loc &= 0xff000000;
 123                         *(u32 *)loc |= offset & 0x00ffffff;
 124                         break;
 125
 126                 default:
 127                         printk(KERN_ERR "%s: unknown relocation: %u\n",
 128                                module->name, ELF32_R_TYPE(rel->r_info));
 129                         return -ENOEXEC;
 130                 }
 131         }
 132         return 0;
 133 }
 134
 135 int
 136 apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
 137                    unsigned int symindex, unsigned int relsec, struct module *module)
 138 {
 139         printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
 140                module->name);
 141         return -ENOEXEC;
 142 }
 143
 144 int
 145 module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 146                 struct module *module)
 147 {
 148         return 0;
 149 }
 150
 151 void
 152 module_arch_cleanup(struct module *mod)
 153 {
 154 }