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module.c

#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);
}

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

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

      DEBUGP("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 *loc = (uint32_t *)(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;

            switch (ELF32_R_TYPE(rela[i].r_info)) {
            case R_H8_DIR24R8:
                  loc = (uint32_t *)((uint32_t)loc - 1);
                  *loc = (*loc & 0xff000000) | ((*loc & 0xffffff) + v);
                  break;
            case R_H8_DIR24A8:
                  if (ELF32_R_SYM(rela[i].r_info))
                        *loc += v;
                  break;
            case R_H8_DIR32:
            case R_H8_DIR32A16:
                  *loc += v;
                  break;
            case R_H8_PCREL16:
                  v -= (unsigned long)loc + 2;
                  if ((Elf32_Sword)v > 0x7fff || 
                      (Elf32_Sword)v < -(Elf32_Sword)0x8000)
                        goto overflow;
                  else 
                        *(unsigned short *)loc = v;
                  break;
            case R_H8_PCREL8:
                  v -= (unsigned long)loc + 1;
                  if ((Elf32_Sword)v > 0x7f || 
                      (Elf32_Sword)v < -(Elf32_Sword)0x80)
                        goto overflow;
                  else 
                        *(unsigned char *)loc = v;
                  break;
            default:
                  printk(KERN_ERR "module %s: Unknown relocation: %u\n",
                         me->name, ELF32_R_TYPE(rela[i].r_info));
                  return -ENOEXEC;
            }
      }
      return 0;
 overflow:
      printk(KERN_ERR "module %s: relocation offset overflow: %08x\n",
             me->name, rela[i].r_offset);
      return -ENOEXEC;
}

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

void module_arch_cleanup(struct module *mod)
{
      module_bug_cleanup(mod);
}

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