module.c

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/*
 * linux/arch/unicore32/kernel/module.c
 *
 * Code specific to PKUnity SoC and UniCore ISA
 *
 * Copyright (C) 2001-2010 GUAN Xue-tao
 *
 * 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/mm.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/gfp.h>

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

void *module_alloc(unsigned long size)
{
    struct vm_struct *area;

    size = PAGE_ALIGN(size);
    if (!size)
        return NULL;

    area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END);
    if (!area)
        return NULL;

    return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL_EXEC);
}

int
apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
           unsigned int relindex, struct module *module)
{
    Elf32_Shdr *symsec = sechdrs + symindex;
    Elf32_Shdr *relsec = sechdrs + relindex;
    Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
    Elf32_Rel *rel = (void *)relsec->sh_addr;
    unsigned int i;

    for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
        unsigned long loc;
        Elf32_Sym *sym;
        s32 offset;

        offset = ELF32_R_SYM(rel->r_info);
        if (offset < 0 || offset >
                (symsec->sh_size / sizeof(Elf32_Sym))) {
            printk(KERN_ERR "%s: bad relocation, "
                    "section %d reloc %d\n",
                    module->name, relindex, i);
            return -ENOEXEC;
        }

        sym = ((Elf32_Sym *)symsec->sh_addr) + offset;

        if (rel->r_offset < 0 || rel->r_offset >
                dstsec->sh_size - sizeof(u32)) {
            printk(KERN_ERR "%s: out of bounds relocation, "
                "section %d reloc %d offset %d size %d\n",
                module->name, relindex, i, rel->r_offset,
                dstsec->sh_size);
            return -ENOEXEC;
        }

        loc = dstsec->sh_addr + rel->r_offset;

        switch (ELF32_R_TYPE(rel->r_info)) {
        case R_UNICORE_NONE:
            /* ignore */
            break;

        case R_UNICORE_ABS32:
            *(u32 *)loc += sym->st_value;
            break;

        case R_UNICORE_PC24:
        case R_UNICORE_CALL:
        case R_UNICORE_JUMP24:
            offset = (*(u32 *)loc & 0x00ffffff) << 2;
            if (offset & 0x02000000)
                offset -= 0x04000000;

            offset += sym->st_value - loc;
            if (offset & 3 ||
                offset <= (s32)0xfe000000 ||
                offset >= (s32)0x02000000) {
                printk(KERN_ERR
                       "%s: relocation out of range, section "
                       "%d reloc %d sym '%s'\n", module->name,
                       relindex, i, strtab + sym->st_name);
                return -ENOEXEC;
            }

            offset >>= 2;

            *(u32 *)loc &= 0xff000000;
            *(u32 *)loc |= offset & 0x00ffffff;
            break;

        default:
            printk(KERN_ERR "%s: unknown relocation: %u\n",
                   module->name, ELF32_R_TYPE(rel->r_info));
            return -ENOEXEC;
        }
    }
    return 0;
}