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/kernel.h>
  14 #include <linux/elf.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/slab.h>
  17 #include <linux/fs.h>
  18 #include <linux/string.h>
  19
  20 #include <asm/pgtable.h>
  21
  22 void *module_alloc(unsigned long size)
  23 {
  24         struct vm_struct *area;
  25         struct page **pages;
  26         unsigned int array_size, i;
  27
  28         size = PAGE_ALIGN(size);
  29         if (!size)
  30                 goto out_null;
  31
  32         area = __get_vm_area(size, VM_ALLOC, MODULE_START, MODULE_END);
  33         if (!area)
  34                 goto out_null;
  35
  36         area->nr_pages = size >> PAGE_SHIFT;
  37         array_size = area->nr_pages * sizeof(struct page *);
  38         area->pages = pages = kmalloc(array_size, GFP_KERNEL);
  39         if (!area->pages) {
  40                 remove_vm_area(area->addr);
  41                 kfree(area);
  42                 goto out_null;
  43         }
  44
  45         memset(pages, 0, array_size);
  46
  47         for (i = 0; i < area->nr_pages; i++) {
  48                 pages[i] = alloc_page(GFP_KERNEL);
  49                 if (unlikely(!pages[i])) {
  50                         area->nr_pages = i;
  51                         goto out_no_pages;
  52                 }
  53         }
  54
  55         if (map_vm_area(area, PAGE_KERNEL, &pages))
  56                 goto out_no_pages;
  57         return area->addr;
  58
  59  out_no_pages:
  60         vfree(area->addr);
  61  out_null:
  62         return NULL;
  63 }
  64
  65 void module_free(struct module *module, void *region)
  66 {
  67         vfree(region);
  68 }
  69
  70 int module_frob_arch_sections(Elf_Ehdr *hdr,
  71                               Elf_Shdr *sechdrs,
  72                               char *secstrings,
  73                               struct module *mod)
  74 {
  75         return 0;
  76 }
  77
  78 int
  79 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
  80                unsigned int relindex, struct module *module)
  81 {
  82         Elf32_Shdr *symsec = sechdrs + symindex;
  83         Elf32_Shdr *relsec = sechdrs + relindex;
  84         Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
  85         Elf32_Rel *rel = (void *)relsec->sh_addr;
  86         unsigned int i;
  87
  88         for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
  89                 unsigned long loc;
  90                 Elf32_Sym *sym;
  91                 s32 offset;
  92
  93                 offset = ELF32_R_SYM(rel->r_info);
  94                 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
  95                         printk(KERN_ERR "%s: bad relocation, section %d reloc %d\n",
  96                                 module->name, relindex, i);
  97                         return -ENOEXEC;
  98                 }
  99
 100                 sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
 101
 102                 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
 103                         printk(KERN_ERR "%s: out of bounds relocation, "
 104                                 "section %d reloc %d offset %d size %d\n",
 105                                 module->name, relindex, i, rel->r_offset,
 106                                 dstsec->sh_size);
 107                         return -ENOEXEC;
 108                 }
 109
 110                 loc = dstsec->sh_addr + rel->r_offset;
 111
 112                 switch (ELF32_R_TYPE(rel->r_info)) {
 113                 case R_ARM_ABS32:
 114                         *(u32 *)loc += sym->st_value;
 115                         break;
 116
 117                 case R_ARM_PC24:
 118                         offset = (*(u32 *)loc & 0x00ffffff) << 2;
 119                         if (offset & 0x02000000)
 120                                 offset -= 0x04000000;
 121
 122                         offset += sym->st_value - loc;
 123                         if (offset & 3 ||
 124                             offset <= (s32)0xfc000000 ||
 125                             offset >= (s32)0x04000000) {
 126                                 printk(KERN_ERR
 127                                        "%s: relocation out of range, section "
 128                                        "%d reloc %d sym '%s'\n", module->name,
 129                                        relindex, i, strtab + sym->st_name);
 130                                 return -ENOEXEC;
 131                         }
 132
 133                         offset >>= 2;
 134
 135                         *(u32 *)loc &= 0xff000000;
 136                         *(u32 *)loc |= offset & 0x00ffffff;
 137                         break;
 138
 139                 default:
 140                         printk(KERN_ERR "%s: unknown relocation: %u\n",
 141                                module->name, ELF32_R_TYPE(rel->r_info));
 142                         return -ENOEXEC;
 143                 }
 144         }
 145         return 0;
 146 }
 147
 148 int
 149 apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
 150                    unsigned int symindex, unsigned int relsec, struct module *module)
 151 {
 152         printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
 153                module->name);
 154         return -ENOEXEC;
 155 }
 156
 157 int
 158 module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
 159                 struct module *module)
 160 {
 161         return 0;
 162 }
 163
 164 void
 165 module_arch_cleanup(struct module *mod)
 166 {
 167 }