/*
 * Kernel module support for Nios II.
 *
 * Copyright (C) 2004 Microtronix Datacom Ltd.
 *   Written by Wentao Xu <xuwentao@microtronix.com>
 * Copyright (C) 2001, 2003 Rusty Russell
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License.  See the file COPYING in the main directory of this
 * archive for more details.
 */

#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>

#include <asm/cacheflush.h>

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

        pr_debug("Applying 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 word;
                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));
                uint32_t v = sym->st_value + rela[i].r_addend;

                pr_debug("reltype %d 0x%x name:<%s>\n",
                        ELF32_R_TYPE(rela[i].r_info),
                        rela[i].r_offset, strtab + sym->st_name);

                switch (ELF32_R_TYPE(rela[i].r_info)) {
                case R_NIOS2_NONE:
                        break;
                case R_NIOS2_BFD_RELOC_32:
                        *loc += v;
                        break;
                case R_NIOS2_PCREL16:
                        v -= (uint32_t)loc + 4;
                        if ((int32_t)v > 0x7fff ||
                                (int32_t)v < -(int32_t)0x8000) {
                                pr_err("module %s: relocation overflow\n",
                                        mod->name);
                                return -ENOEXEC;
                        }
                        word = *loc;
                        *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
                                (word & 0x3f);
                        break;
                case R_NIOS2_CALL26:
                        if (v & 3) {
                                pr_err("module %s: dangerous relocation\n",
                                        mod->name);
                                return -ENOEXEC;
                        }
                        if ((v >> 28) != ((uint32_t)loc >> 28)) {
                                pr_err("module %s: relocation overflow\n",
                                        mod->name);
                                return -ENOEXEC;
                        }
                        *loc = (*loc & 0x3f) | ((v >> 2) << 6);
                        break;
                case R_NIOS2_HI16:
                        word = *loc;
                        *loc = ((((word >> 22) << 16) |
                                ((v >> 16) & 0xffff)) << 6) | (word & 0x3f);
                        break;
                case R_NIOS2_LO16:
                        word = *loc;
                        *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
                                        (word & 0x3f);
                        break;
                case R_NIOS2_HIADJ16:
                        {
                                Elf32_Addr word2;

                                word = *loc;
                                word2 = ((v >> 16) + ((v >> 15) & 1)) & 0xffff;
                                *loc = ((((word >> 22) << 16) | word2) << 6) |
                                                (word & 0x3f);
                        }
                        break;

                default:
                        pr_err("module %s: Unknown reloc: %u\n",
                                mod->name, ELF32_R_TYPE(rela[i].r_info));
                        return -ENOEXEC;
                }
        }

        return 0;
}

int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
                        struct module *me)
{
        flush_cache_all();
        return 0;
}