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/* dl.c - arch-dependent part of loadable module support */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2002,2004,2005,2007 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/dl.h>
#include <grub/elf.h>
#include <grub/misc.h>
#include <grub/err.h>
/* Check if EHDR is a valid ELF header. */
grub_err_t
grub_arch_dl_check_header (void *ehdr)
{
Elf_Ehdr *e = ehdr;
/* Check the magic numbers. */
if (e->e_ident[EI_CLASS] != ELFCLASS32
|| e->e_ident[EI_DATA] != ELFDATA2MSB
|| e->e_machine != EM_PPC)
return grub_error (GRUB_ERR_BAD_OS, "invalid arch specific ELF magic");
return GRUB_ERR_NONE;
}
/* Relocate symbols. */
grub_err_t
grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr)
{
Elf_Ehdr *e = ehdr;
Elf_Shdr *s;
Elf_Word entsize;
unsigned i;
/* Find a symbol table. */
for (i = 0, s = (Elf_Shdr *) ((char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf_Shdr *) ((char *) s + e->e_shentsize))
if (s->sh_type == SHT_SYMTAB)
break;
if (i == e->e_shnum)
return grub_error (GRUB_ERR_BAD_MODULE, "no symtab found");
entsize = s->sh_entsize;
for (i = 0, s = (Elf_Shdr *) ((char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf_Shdr *) ((char *) s + e->e_shentsize))
if (s->sh_type == SHT_RELA)
{
grub_dl_segment_t seg;
/* Find the target segment. */
for (seg = mod->segment; seg; seg = seg->next)
if (seg->section == s->sh_info)
break;
if (seg)
{
Elf_Rela *rel, *max;
for (rel = (Elf_Rela *) ((char *) e + s->sh_offset),
max = rel + s->sh_size / s->sh_entsize;
rel < max;
rel++)
{
Elf_Word *addr;
Elf_Sym *sym;
grub_uint32_t value;
if (seg->size < rel->r_offset)
return grub_error (GRUB_ERR_BAD_MODULE,
"reloc offset is out of the segment");
addr = (Elf_Word *) ((char *) seg->addr + rel->r_offset);
sym = (Elf_Sym *) ((char *) mod->symtab
+ entsize * ELF_R_SYM (rel->r_info));
/* On the PPC the value does not have an explicit
addend, add it. */
value = sym->st_value + rel->r_addend;
switch (ELF_R_TYPE (rel->r_info))
{
case R_PPC_ADDR16_LO:
*(Elf_Half *) addr = value;
break;
case R_PPC_REL24:
{
Elf_Sword delta = value - (Elf_Word) addr;
if (delta << 6 >> 6 != delta)
return grub_error (GRUB_ERR_BAD_MODULE, "Relocation overflow");
*addr = (*addr & 0xfc000003) | (delta & 0x3fffffc);
break;
}
case R_PPC_ADDR16_HA:
*(Elf_Half *) addr = (value + 0x8000) >> 16;
break;
case R_PPC_ADDR32:
*addr = value;
break;
case R_PPC_REL32:
*addr = value - (Elf_Word) addr;
break;
default:
return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
"This relocation (%d) is not implemented yet",
ELF_R_TYPE (rel->r_info));
}
}
}
}
return GRUB_ERR_NONE;
}
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