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/config.h>
  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 void *module_alloc(unsigned long size)
  37 {
  38         struct vm_struct *area;
  39
  40         size = PAGE_ALIGN(size);
  41         if (!size)
  42                 return NULL;
  43
  44         area = __get_vm_area(size, VM_ALLOC, MODULE_START, MODULE_END);
  45         if (!area)
  46                 return NULL;
  47
  48         return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL);
  49 }
  50
  51 void module_free(struct module *module, void *region)
  52 {
  53         vfree(region);
  54 }
  55
  56 int module_frob_arch_sections(Elf_Ehdr *hdr,
  57                               Elf_Shdr *sechdrs,
  58                               char *secstrings,
  59                               struct module *mod)
  60 {
  61         return 0;
  62 }
  63
  64 int
  65 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
  66                unsigned int relindex, struct module *module)
  67 {
  68         Elf32_Shdr *symsec = sechdrs + symindex;
  69         Elf32_Shdr *relsec = sechdrs + relindex;
  70         Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
  71         Elf32_Rel *rel = (void *)relsec->sh_addr;
  72         unsigned int i;
  73
  74         for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
  75                 unsigned long loc;
  76                 Elf32_Sym *sym;
  77                 s32 offset;
  78
  79                 offset = ELF32_R_SYM(rel->r_info);
  80                 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
  81                         printk(KERN_ERR "%s: bad relocation, section %d reloc %d\n",
  82                                 module->name, relindex, i);
  83                         return -ENOEXEC;
  84                 }
  85
  86                 sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
  87
  88                 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
  89                         printk(KERN_ERR "%s: out of bounds relocation, "
  90                                 "section %d reloc %d offset %d size %d\n",
  91                                 module->name, relindex, i, rel->r_offset,
  92                                 dstsec->sh_size);
  93                         return -ENOEXEC;
  94                 }
  95
  96                 loc = dstsec->sh_addr + rel->r_offset;
  97
  98                 switch (ELF32_R_TYPE(rel->r_info)) {
  99                 case R_ARM_ABS32:
 100                         *(u32 *)loc += sym->st_value;
 101                         break;
 102
 103                 case R_ARM_PC24:
 104                 case R_ARM_CALL:
 105                 case R_ARM_JUMP24:
 106                         offset = (*(u32 *)loc & 0x00ffffff) << 2;
 107                         if (offset & 0x02000000)
 108                                 offset -= 0x04000000;
 109
 110                         offset += sym->st_value - loc;
 111                         if (offset & 3 ||
 112                             offset <= (s32)0xfc000000 ||
 113                             offset >= (s32)0x04000000) {
 114                                 printk(KERN_ERR
 115                                        "%s: relocation out of range, section "
 116                                        "%d reloc %d sym '%s'\n", module->name,
 117                                        relindex, i, strtab + sym->st_name);
 118                                 return -ENOEXEC;
 119                         }
 120
 121                         offset >>= 2;
 122
 123                         *(u32 *)loc &= 0xff000000;
 124                         *(u32 *)loc |= offset & 0x00ffffff;
 125                         break;
 126
 127                 default:
 128                         printk(KERN_ERR "%s: unknown relocation: %u\n",
 129                                module->name, ELF32_R_TYPE(rel->r_info));
 130                         return -ENOEXEC;
 131                 }
 132         }
 133         return 0;
 134 }
 135
 136 int
 137 apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
 138                    unsigned int symindex, unsigned int relsec, struct module *module)
 139 {
 140         printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
 141                module->name);
 142         return -ENOEXEC;
 143 }
 144
 145 int
 146 module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 147                 struct module *module)
 148 {
 149         return 0;
 150 }
 151
 152 void
 153 module_arch_cleanup(struct module *mod)
 154 {
 155 }