module.c

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/*
 * Copyright (C) 2007-2009 Michal Simek <[email protected]>
 * Copyright (C) 2007-2009 PetaLogix
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/moduleloader.h>
#include <linux/kernel.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/string.h>

#include <asm/pgtable.h>
#include <asm/cacheflush.h>

int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
    unsigned int symindex, unsigned int relsec, struct module *module)
{

    unsigned int i;
    Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
    Elf32_Sym *sym;
    unsigned long int *location;
    unsigned long int value;
#if __GNUC__ < 4
    unsigned long int old_value;
#endif

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

    for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {

        location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr +
                rela[i].r_offset;
        sym = (Elf32_Sym *)sechdrs[symindex].sh_addr +
            ELF32_R_SYM(rela[i].r_info);
        value = sym->st_value + rela[i].r_addend;

        switch (ELF32_R_TYPE(rela[i].r_info)) {

        /*
         * Be careful! mb-gcc / mb-ld splits the relocs between the
         * text and the reloc table. In general this means we must
         * read the current contents of (*location), add any offset
         * then store the result back in
         */

        case R_MICROBLAZE_32:
#if __GNUC__ < 4
            old_value = *location;
            *location = value + old_value;

            pr_debug("R_MICROBLAZE_32 (%08lx->%08lx)\n",
                old_value, value);
#else
            *location = value;
#endif
            break;

        case R_MICROBLAZE_64:
#if __GNUC__ < 4
            /* Split relocs only required/used pre gcc4.1.1 */
            old_value = ((location[0] & 0x0000FFFF) << 16) |
                    (location[1] & 0x0000FFFF);
            value += old_value;
#endif
            location[0] = (location[0] & 0xFFFF0000) |
                    (value >> 16);
            location[1] = (location[1] & 0xFFFF0000) |
                    (value & 0xFFFF);
#if __GNUC__ < 4
            pr_debug("R_MICROBLAZE_64 (%08lx->%08lx)\n",
                old_value, value);
#endif
            break;

        case R_MICROBLAZE_64_PCREL:
#if __GNUC__ < 4
            old_value = (location[0] & 0xFFFF) << 16 |
                (location[1] & 0xFFFF);
            value -= old_value;
#endif
            value -= (unsigned long int)(location) + 4;
            location[0] = (location[0] & 0xFFFF0000) |
                    (value >> 16);
            location[1] = (location[1] & 0xFFFF0000) |
                    (value & 0xFFFF);
            pr_debug("R_MICROBLAZE_64_PCREL (%08lx)\n",
                value);
            break;

        case R_MICROBLAZE_32_PCREL_LO:
            pr_debug("R_MICROBLAZE_32_PCREL_LO\n");
            break;

        case R_MICROBLAZE_64_NONE:
            pr_debug("R_MICROBLAZE_64_NONE\n");
            break;

        case R_MICROBLAZE_NONE:
            pr_debug("R_MICROBLAZE_NONE\n");
            break;

        default:
            printk(KERN_ERR "module %s: "
                "Unknown relocation: %u\n",
                module->name,
                ELF32_R_TYPE(rela[i].r_info));
            return -ENOEXEC;
        }
    }
    return 0;
}

int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
        struct module *module)
{
    flush_dcache();
    return 0;
}