module.c

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/*  Kernel module help for i386.
    Copyright (C) 2001 Rusty Russell.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/slab.h>

#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt , ...)
#endif

#ifdef CONFIG_ETRAX_KMALLOCED_MODULES
void *module_alloc(unsigned long size)
{
    if (size == 0)
        return NULL;
    return kmalloc(size, GFP_KERNEL);
}

/* Free memory returned from module_alloc */
void module_free(struct module *mod, void *module_region)
{
    kfree(module_region);
}
#endif

int apply_relocate_add(Elf32_Shdr *sechdrs,
               const char *strtab,
               unsigned int symindex,
               unsigned int relsec,
               struct module *me)
{
    unsigned int i;
    Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;

    DEBUGP ("Applying add relocate section %u to %u\n", relsec,
        sechdrs[relsec].sh_info);

    for (i = 0; i < sechdrs[relsec].sh_size / sizeof (*rela); i++) {
        /* This is where to make the change */
        uint32_t *loc
            = ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
               + rela[i].r_offset);
        /* This is the symbol it is referring to.  Note that all
           undefined symbols have been resolved.  */
        Elf32_Sym *sym
            = ((Elf32_Sym *)sechdrs[symindex].sh_addr
               + ELF32_R_SYM (rela[i].r_info));
        switch (ELF32_R_TYPE(rela[i].r_info)) {
        case R_CRIS_32:
            *loc = sym->st_value + rela[i].r_addend;
            break;
        case R_CRIS_32_PCREL:
            *loc = sym->st_value - (unsigned)loc + rela[i].r_addend - 4;
             break;
        default:
            printk(KERN_ERR "module %s: Unknown relocation: %u\n",
                   me->name, ELF32_R_TYPE(rela[i].r_info));
            return -ENOEXEC;
        }
    }

    return 0;
}