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module.c

/*  Kernel module help for sh64.

    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

    Copyright 2004 SuperH (UK) Ltd
    Author: Richard Curnow

    Based on the sh version, and on code from the sh64-specific parts of
    modutils, originally written by Richard Curnow and Ben Gaster.

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

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

void *module_alloc(unsigned long size)
{
      if (size == 0)
            return NULL;
      return vmalloc(size);
}


/* Free memory returned from module_alloc */
void module_free(struct module *mod, void *module_region)
{
      vfree(module_region);
      /* FIXME: If module_region == mod->init_region, trim exception
           table entries. */
}

/* We don't need anything special. */
int module_frob_arch_sections(Elf_Ehdr *hdr,
                        Elf_Shdr *sechdrs,
                        char *secstrings,
                        struct module *mod)
{
      return 0;
}

int apply_relocate_add(Elf32_Shdr *sechdrs,
               const char *strtab,
               unsigned int symindex,
               unsigned int relsec,
               struct module *me)
{
      unsigned int i;
      Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
      Elf32_Sym *sym;
      Elf32_Addr relocation;
      uint32_t *location;
      int align;
      int is_shmedia;

      DEBUGP("Applying relocate section %u to %u\n", relsec,
             sechdrs[relsec].sh_info);
      for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
            /* This is where to make the change */
            location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
                  + rel[i].r_offset;
            /* This is the symbol it is referring to.  Note that all
               undefined symbols have been resolved.  */
            sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
                  + ELF32_R_SYM(rel[i].r_info);
            relocation = sym->st_value + rel[i].r_addend;
            align = (int)location & 3;

            /* For text addresses, bit2 of the st_other field indicates
             * whether the symbol is SHmedia (1) or SHcompact (0).  If
             * SHmedia, the LSB of the symbol needs to be asserted
             * for the CPU to be in SHmedia mode when it starts executing
             * the branch target. */
            is_shmedia = (sym->st_other & 4) ? 1 : 0;
            if (is_shmedia) {
                  relocation |= 1;
            }

            switch (ELF32_R_TYPE(rel[i].r_info)) {
            case R_SH_DIR32:
                  DEBUGP("R_SH_DIR32 @%08lx = %08lx\n", (unsigned long) location, (unsigned long) relocation);
                  *location += relocation;
                  break;
            case R_SH_REL32:
                  DEBUGP("R_SH_REL32 @%08lx = %08lx\n", (unsigned long) location, (unsigned long) relocation);
                  relocation -= (Elf32_Addr) location;
                  *location += relocation;
                  break;
            case R_SH_IMM_LOW16:
                  DEBUGP("R_SH_IMM_LOW16 @%08lx = %08lx\n", (unsigned long) location, (unsigned long) relocation);
                  *location = (*location & ~0x3fffc00) |
                        ((relocation & 0xffff) << 10);
                  break;
            case R_SH_IMM_MEDLOW16:
                  DEBUGP("R_SH_IMM_MEDLOW16 @%08lx = %08lx\n", (unsigned long) location, (unsigned long) relocation);
                  *location = (*location & ~0x3fffc00) |
                        (((relocation >> 16) & 0xffff) << 10);
                  break;
            case R_SH_IMM_LOW16_PCREL:
                  DEBUGP("R_SH_IMM_LOW16_PCREL @%08lx = %08lx\n", (unsigned long) location, (unsigned long) relocation);
                  relocation -= (Elf32_Addr) location;
                  *location = (*location & ~0x3fffc00) |
                        ((relocation & 0xffff) << 10);
                  break;
            case R_SH_IMM_MEDLOW16_PCREL:
                  DEBUGP("R_SH_IMM_MEDLOW16_PCREL @%08lx = %08lx\n", (unsigned long) location, (unsigned long) relocation);
                  relocation -= (Elf32_Addr) location;
                  *location = (*location & ~0x3fffc00) |
                        (((relocation >> 16) & 0xffff) << 10);
                  break;
            default:
                  printk(KERN_ERR "module %s: Unknown relocation: %u\n",
                         me->name, ELF32_R_TYPE(rel[i].r_info));
                  return -ENOEXEC;
            }
      }
      return 0;
}

int apply_relocate(Elf32_Shdr *sechdrs,
                   const char *strtab,
                   unsigned int symindex,
                   unsigned int relsec,
                   struct module *me)
{
      printk(KERN_ERR "module %s: REL RELOCATION unsupported\n",
             me->name);
      return -ENOEXEC;
}

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

void module_arch_cleanup(struct module *mod)
{
}


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