efiemu/i386/loadcore32.c

   1 /* i386 CPU-specific part of loadcore.c for 32-bit mode */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2009  Free Software Foundation, Inc.
   5  *
   6  *  GRUB is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  GRUB is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <grub/err.h>
  21 #include <grub/mm.h>
  22 #include <grub/misc.h>
  23 #include <grub/efiemu/efiemu.h>
  24 #include <grub/cpu/efiemu.h>
  25 #include <grub/elf.h>
  26
  27 /* Check if EHDR is a valid ELF header.  */
  28 int
  29 grub_arch_efiemu_check_header32 (void *ehdr)
  30 {
  31   Elf32_Ehdr *e = ehdr;
  32
  33   /* Check the magic numbers.  */
  34   return (e->e_ident[EI_CLASS] == ELFCLASS32
  35           && e->e_ident[EI_DATA] == ELFDATA2LSB
  36           && e->e_machine == EM_386);
  37 }
  38
  39 /* Relocate symbols.  */
  40 grub_err_t
  41 grub_arch_efiemu_relocate_symbols32 (grub_efiemu_segment_t segs,
  42                                      struct grub_efiemu_elf_sym *elfsyms,
  43                                      void *ehdr)
  44 {
  45   unsigned i;
  46   Elf32_Ehdr *e = ehdr;
  47   Elf32_Shdr *s;
  48   grub_err_t err;
  49
  50   grub_dprintf ("efiemu", "relocating symbols %d %d\n",
  51                 e->e_shoff, e->e_shnum);
  52
  53   for (i = 0, s = (Elf32_Shdr *) ((char *) e + e->e_shoff);
  54        i < e->e_shnum;
  55        i++, s = (Elf32_Shdr *) ((char *) s + e->e_shentsize))
  56     if (s->sh_type == SHT_REL)
  57       {
  58         grub_efiemu_segment_t seg;
  59         grub_dprintf ("efiemu", "shtrel\n");
  60
  61         /* Find the target segment.  */
  62         for (seg = segs; seg; seg = seg->next)
  63           if (seg->section == s->sh_info)
  64             break;
  65
  66         if (seg)
  67           {
  68             Elf32_Rel *rel, *max;
  69
  70             for (rel = (Elf32_Rel *) ((char *) e + s->sh_offset),
  71                    max = rel + s->sh_size / s->sh_entsize;
  72                  rel < max;
  73                  rel++)
  74               {
  75                 Elf32_Word *addr;
  76                 struct grub_efiemu_elf_sym sym;
  77                 if (seg->size < rel->r_offset)
  78                   return grub_error (GRUB_ERR_BAD_MODULE,
  79                                      "reloc offset is out of the segment");
  80
  81                 addr = (Elf32_Word *)
  82                   ((char *) grub_efiemu_mm_obtain_request (seg->handle)
  83                    + seg->off + rel->r_offset);
  84                 sym = elfsyms[ELF32_R_SYM (rel->r_info)];
  85
  86                 switch (ELF32_R_TYPE (rel->r_info))
  87                   {
  88                   case R_386_32:
  89                     if ((err = grub_efiemu_write_value
  90                          (addr, sym.off + *addr, sym.handle, 0,
  91                           seg->ptv_rel_needed, sizeof (grub_uint32_t))))
  92                       return err;
  93
  94                     break;
  95
  96                   case R_386_PC32:
  97                     if ((err = grub_efiemu_write_value
  98                          (addr, sym.off + *addr - rel->r_offset
  99                           - seg->off, sym.handle, seg->handle,
 100                           seg->ptv_rel_needed, sizeof (grub_uint32_t))))
 101                       return err;
 102                     break;
 103                   default:
 104                     return grub_error (GRUB_ERR_BAD_OS,
 105                                        "unrecognised relocation");
 106                   }
 107               }
 108           }
 109       }
 110
 111   return GRUB_ERR_NONE;
 112 }
 113
 114