LXR linux/arch/i386/kernel/module.c

   1/*  Kernel module help for i386.
   2    Copyright (C) 2001 Rusty Russell.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17*/
  18#include <linux/moduleloader.h>
  19#include <linux/elf.h>
  20#include <linux/vmalloc.h>
  21#include <linux/fs.h>
  22#include <linux/string.h>
  23#include <linux/kernel.h>
  24#include <linux/bug.h>
  25
  26#if 0
  27#define DEBUGP printk
  28#else
  29#define DEBUGP(fmt...)
  30#endif
  31
  32void *module_alloc(unsigned long size)
  33{
  34        if (size == 0)
  35                return NULL;
  36        return vmalloc_exec(size);
  37}
  38
  39
  40/* Free memory returned from module_alloc */
  41void module_free(struct module *mod, void *module_region)
  42{
  43        vfree(module_region);
  44        /* FIXME: If module_region == mod->init_region, trim exception
  45           table entries. */
  46}
  47
  48/* We don't need anything special. */
  49int module_frob_arch_sections(Elf_Ehdr *hdr,
  50                              Elf_Shdr *sechdrs,
  51                              char *secstrings,
  52                              struct module *mod)
  53{
  54        return 0;
  55}
  56
  57int apply_relocate(Elf32_Shdr *sechdrs,
  58                   const char *strtab,
  59                   unsigned int symindex,
  60                   unsigned int relsec,
  61                   struct module *me)
  62{
  63        unsigned int i;
  64        Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
  65        Elf32_Sym *sym;
  66        uint32_t *location;
  67
  68        DEBUGP("Applying relocate section %u to %u\n", relsec,
  69               sechdrs[relsec].sh_info);
  70        for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  71                /* This is where to make the change */
  72                location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  73                        + rel[i].r_offset;
  74                /* This is the symbol it is referring to.  Note that all
  75                   undefined symbols have been resolved.  */
  76                sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
  77                        + ELF32_R_SYM(rel[i].r_info);
  78
  79                switch (ELF32_R_TYPE(rel[i].r_info)) {
  80                case R_386_32:
  81                        /* We add the value into the location given */
  82                        *location += sym->st_value;
  83                        break;
  84                case R_386_PC32:
  85                        /* Add the value, subtract its postition */
  86                        *location += sym->st_value - (uint32_t)location;
  87                        break;
  88                default:
  89                        printk(KERN_ERR "module %s: Unknown relocation: %u\n",
  90                               me->name, ELF32_R_TYPE(rel[i].r_info));
  91                        return -ENOEXEC;
  92                }
  93        }
  94        return 0;
  95}
  96
  97int apply_relocate_add(Elf32_Shdr *sechdrs,
  98                       const char *strtab,
  99                       unsigned int symindex,
 100                       unsigned int relsec,
 101                       struct module *me)
 102{
 103        printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
 104               me->name);
 105        return -ENOEXEC;
 106}
 107
 108int module_finalize(const Elf_Ehdr *hdr,
 109                    const Elf_Shdr *sechdrs,
 110                    struct module *me)
 111{
 112        const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
 113                *para = NULL;
 114        char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 115
 116        for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { 
 117                if (!strcmp(".text", secstrings + s->sh_name))
 118                        text = s;
 119                if (!strcmp(".altinstructions", secstrings + s->sh_name))
 120                        alt = s;
 121                if (!strcmp(".smp_locks", secstrings + s->sh_name))
 122                        locks= s;
 123                if (!strcmp(".parainstructions", secstrings + s->sh_name))
 124                        para = s;
 125        }
 126
 127        if (alt) {
 128                /* patch .altinstructions */
 129                void *aseg = (void *)alt->sh_addr;
 130                apply_alternatives(aseg, aseg + alt->sh_size);
 131        }
 132        if (locks && text) {
 133                void *lseg = (void *)locks->sh_addr;
 134                void *tseg = (void *)text->sh_addr;
 135                alternatives_smp_module_add(me, me->name,
 136                                            lseg, lseg + locks->sh_size,
 137                                            tseg, tseg + text->sh_size);
 138        }
 139
 140        if (para) {
 141                void *pseg = (void *)para->sh_addr;
 142                apply_paravirt(pseg, pseg + para->sh_size);
 143        }
 144
 145        return module_bug_finalize(hdr, sechdrs, me);
 146}
 147
 148void module_arch_cleanup(struct module *mod)
 149{
 150        alternatives_smp_module_del(mod);
 151        module_bug_cleanup(mod);
 152}
 153