grub/grub-core/kern/arm64/dl.c

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2013-11-16 19:52:55 +00:00
/* dl.c - arch-dependent part of loadable module support */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2013 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>
#include <grub/mm.h>
#include <grub/i18n.h>
#include <grub/cpu/reloc.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] != ELFCLASS64
|| e->e_ident[EI_DATA] != ELFDATA2LSB || e->e_machine != EM_AARCH64)
return grub_error (GRUB_ERR_BAD_OS,
N_("invalid arch-dependent ELF magic"));
return GRUB_ERR_NONE;
}
/*
* Unified function for both REL and RELA
*/
static grub_err_t
do_relX (Elf_Shdr * relhdr, Elf_Ehdr * e, grub_dl_t mod)
{
grub_err_t retval;
grub_dl_segment_t segment;
Elf_Rel *rel;
Elf_Rela *rela;
Elf_Sym *symbol;
int i, entnum;
unsigned long long entsize;
/* Find the target segment for this relocation section. */
for (segment = mod->segment ; segment != 0 ; segment = segment->next)
if (segment->section == relhdr->sh_info)
break;
if (!segment)
return grub_error (GRUB_ERR_EOF, N_("relocation segment not found"));
rel = (Elf_Rel *) ((grub_addr_t) e + relhdr->sh_offset);
rela = (Elf_Rela *) rel;
if (relhdr->sh_type == SHT_RELA)
entsize = sizeof (Elf_Rela);
else
entsize = sizeof (Elf_Rel);
entnum = relhdr->sh_size / entsize;
retval = GRUB_ERR_NONE;
grub_dprintf("dl", "Processing %d relocation entries.\n", entnum);
/* Step through all relocations */
for (i = 0, symbol = mod->symtab; i < entnum; i++)
{
void *place;
grub_uint64_t sym_addr, symidx, reltype;
if (rel->r_offset >= segment->size)
return grub_error (GRUB_ERR_BAD_MODULE,
"reloc offset is out of the segment");
symidx = ELF_R_SYM (rel->r_info);
reltype = ELF_R_TYPE (rel->r_info);
sym_addr = symbol[symidx].st_value;
if (relhdr->sh_type == SHT_RELA)
sym_addr += rela->r_addend;
place = (void *) ((grub_addr_t) segment->addr + rel->r_offset);
switch (reltype)
{
case R_AARCH64_ABS64:
{
grub_uint64_t *abs_place = place;
grub_dprintf ("dl", " reloc_abs64 %p => 0x%016llx\n",
place, (unsigned long long) sym_addr);
*abs_place = (grub_uint64_t) sym_addr;
}
break;
case R_AARCH64_CALL26:
case R_AARCH64_JUMP26:
retval = grub_arm64_reloc_xxxx26 (place, sym_addr);
break;
default:
return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
N_("relocation 0x%x is not implemented yet"),
reltype);
}
if (retval != GRUB_ERR_NONE)
break;
rel = (Elf_Rel *) ((grub_addr_t) rel + entsize);
rela++;
}
return retval;
}
/*
* Verify that provided ELF header contains reference to a symbol table
*/
static int
has_symtab (Elf_Ehdr * e)
{
int i;
Elf_Shdr *s;
for (i = 0, s = (Elf_Shdr *) ((grub_addr_t) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf_Shdr *) ((grub_addr_t) s + e->e_shentsize))
if (s->sh_type == SHT_SYMTAB)
return 1;
return 0;
}
/*
* grub_arch_dl_relocate_symbols():
* Locates the relocations section of the ELF object, and calls
* do_relX() to deal with it.
*/
grub_err_t
grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr)
{
Elf_Ehdr *e = ehdr;
Elf_Shdr *s;
unsigned i;
if (!has_symtab (e))
return grub_error (GRUB_ERR_BAD_MODULE, N_("no symbol table"));
#define FIRST_SHDR(x) ((Elf_Shdr *) ((grub_addr_t)(x) + (x)->e_shoff))
#define NEXT_SHDR(x, y) ((Elf_Shdr *) ((grub_addr_t)(y) + (x)->e_shentsize))
for (i = 0, s = FIRST_SHDR (e); i < e->e_shnum; i++, s = NEXT_SHDR (e, s))
{
grub_err_t ret;
switch (s->sh_type)
{
case SHT_REL:
case SHT_RELA:
{
ret = do_relX (s, e, mod);
if (ret != GRUB_ERR_NONE)
return ret;
}
break;
case SHT_ARM_ATTRIBUTES:
case SHT_NOBITS:
case SHT_NULL:
case SHT_PROGBITS:
case SHT_SYMTAB:
case SHT_STRTAB:
break;
default:
{
grub_dprintf ("dl", "unhandled section_type: %d (0x%08x)\n",
s->sh_type, s->sh_type);
return GRUB_ERR_NOT_IMPLEMENTED_YET;
};
}
}
#undef FIRST_SHDR
#undef NEXT_SHDR
return GRUB_ERR_NONE;
}