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module.c

/*  Kernel module help for M32R.

    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>

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

void *module_alloc(unsigned long size)
{
      if (size == 0)
            return NULL;
#ifdef CONFIG_MMU
      return vmalloc_exec(size);
#else
      return vmalloc(size);
#endif
}


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

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

#define COPY_UNALIGNED_WORD(sw, tw, align) \
{ \
      void *__s = &(sw), *__t = &(tw); \
      unsigned short *__s2 = __s, *__t2 =__t; \
      unsigned char *__s1 = __s, *__t1 =__t; \
      switch ((align)) \
      { \
      case 0: \
            *(unsigned long *) __t = *(unsigned long *) __s; \
            break; \
      case 2: \
            *__t2++ = *__s2++; \
            *__t2 = *__s2; \
            break; \
      default: \
            *__t1++ = *__s1++; \
            *__t1++ = *__s1++; \
            *__t1++ = *__s1++; \
            *__t1 = *__s1; \
            break; \
      } \
}

#define COPY_UNALIGNED_HWORD(sw, tw, align) \
  { \
    void *__s = &(sw), *__t = &(tw); \
    unsigned short *__s2 = __s, *__t2 =__t; \
    unsigned char *__s1 = __s, *__t1 =__t; \
    switch ((align)) \
    { \
    case 0: \
      *__t2 = *__s2; \
      break; \
    default: \
      *__t1++ = *__s1++; \
      *__t1 = *__s1; \
      break; \
    } \
  }

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;
      uint32_t value;
      unsigned short *hlocation;
      unsigned short hvalue;
      int svalue;
      int align;

      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;

            switch (ELF32_R_TYPE(rel[i].r_info)) {
            case R_M32R_32_RELA:
                  COPY_UNALIGNED_WORD (*location, value, align);
                  value += relocation;
                  COPY_UNALIGNED_WORD (value, *location, align);
                  break;
            case R_M32R_HI16_ULO_RELA:
                  COPY_UNALIGNED_WORD (*location, value, align);
                        relocation = (relocation >>16) & 0xffff;
                  /* RELA must has 0 at relocation field. */
                  value += relocation;
                  COPY_UNALIGNED_WORD (value, *location, align);
                  break;
            case R_M32R_HI16_SLO_RELA:
                  COPY_UNALIGNED_WORD (*location, value, align);
                  if (relocation & 0x8000) relocation += 0x10000;
                        relocation = (relocation >>16) & 0xffff;
                  /* RELA must has 0 at relocation field. */
                  value += relocation;
                  COPY_UNALIGNED_WORD (value, *location, align);
                  break;
            case R_M32R_16_RELA:
                  hlocation = (unsigned short *)location;
                        relocation = relocation & 0xffff;
                  /* RELA must has 0 at relocation field. */
                  hvalue = relocation;
                  COPY_UNALIGNED_WORD (hvalue, *hlocation, align);
                  break;
            case R_M32R_SDA16_RELA:
            case R_M32R_LO16_RELA:
                  COPY_UNALIGNED_WORD (*location, value, align);
                        relocation = relocation & 0xffff;
                  /* RELA must has 0 at relocation field. */
                  value += relocation;
                  COPY_UNALIGNED_WORD (value, *location, align);
                  break;
            case R_M32R_24_RELA:
                  COPY_UNALIGNED_WORD (*location, value, align);
                        relocation = relocation & 0xffffff;
                  /* RELA must has 0 at relocation field. */
                  value += relocation;
                  COPY_UNALIGNED_WORD (value, *location, align);
                  break;
            case R_M32R_18_PCREL_RELA:
                  relocation = (relocation - (Elf32_Addr) location);
                  if (relocation < -0x20000 || 0x1fffc < relocation)
                        {
                              printk(KERN_ERR "module %s: relocation overflow: %u\n",
                              me->name, relocation);
                              return -ENOEXEC;
                        }
                  COPY_UNALIGNED_WORD (*location, value, align);
                  if (value & 0xffff)
                        {
                              /* RELA must has 0 at relocation field. */
                              printk(KERN_ERR "module %s: illegal relocation field: %u\n",
                              me->name, value);
                              return -ENOEXEC;
                        }
                        relocation = (relocation >> 2) & 0xffff;
                  value += relocation;
                  COPY_UNALIGNED_WORD (value, *location, align);
                  break;
            case R_M32R_10_PCREL_RELA:
                  hlocation = (unsigned short *)location;
                  relocation = (relocation - (Elf32_Addr) location);
                  COPY_UNALIGNED_HWORD (*hlocation, hvalue, align);
                  svalue = (int)hvalue;
                  svalue = (signed char)svalue << 2;
                  relocation += svalue;
                        relocation = (relocation >> 2) & 0xff;
                  hvalue = hvalue & 0xff00;
                  hvalue += relocation;
                  COPY_UNALIGNED_HWORD (hvalue, *hlocation, align);
                  break;
            case R_M32R_26_PCREL_RELA:
                  relocation = (relocation - (Elf32_Addr) location);
                  if (relocation < -0x2000000 || 0x1fffffc < relocation)
                        {
                              printk(KERN_ERR "module %s: relocation overflow: %u\n",
                              me->name, relocation);
                              return -ENOEXEC;
                        }
                  COPY_UNALIGNED_WORD (*location, value, align);
                  if (value & 0xffffff)
                        {
                              /* RELA must has 0 at relocation field. */
                              printk(KERN_ERR "module %s: illegal relocation field: %u\n",
                              me->name, value);
                              return -ENOEXEC;
                        }
                        relocation = (relocation >> 2) & 0xffffff;
                  value += relocation;
                  COPY_UNALIGNED_WORD (value, *location, align);
                  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)
{
#if 0
      printk(KERN_ERR "module %s: REL RELOCATION unsupported\n",
             me->name);
      return -ENOEXEC;
#endif
      return 0;

}

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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