/* 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 .
*/
#include
#include
#include
#include
#include
#include
#include
/*
* R_ARM_ABS32
*
* Simple relocation of 32-bit value (in literal pool)
*/
grub_err_t
grub_arm_reloc_abs32 (Elf32_Word *target, Elf32_Addr sym_addr)
{
Elf32_Addr tmp;
tmp = grub_le_to_cpu32 (*target);
tmp += sym_addr;
*target = grub_cpu_to_le32 (tmp);
grub_dprintf ("dl", " %s: reloc_abs32 0x%08x => 0x%08x", __FUNCTION__,
(unsigned int) sym_addr, (unsigned int) tmp);
return GRUB_ERR_NONE;
}
/********************************************************************
* Thumb (T32) relocations: *
* *
* 32-bit Thumb instructions can be 16-bit aligned, and are fetched *
* little-endian, requiring some additional fiddling. *
********************************************************************/
/*
* R_ARM_THM_CALL/THM_JUMP24
*
* Relocate Thumb (T32) instruction set relative branches:
* B.W, BL and BLX
*/
grub_err_t
grub_arm_reloc_thm_call (grub_uint16_t *target, Elf32_Addr sym_addr)
{
grub_int32_t offset, offset_low, offset_high;
grub_uint32_t sign, j1, j2, is_blx;
grub_uint32_t insword, insmask;
/* Extract instruction word in alignment-safe manner */
insword = (grub_le_to_cpu16 (*target) << 16)
| (grub_le_to_cpu16(*(target + 1)));
insmask = 0xf800d000;
/* B.W/BL or BLX? Affects range and expected target state */
if (((insword >> 12) & 0xd) == 0xc)
is_blx = 1;
else
is_blx = 0;
/* If BLX, target symbol must be ARM (target address LSB == 0) */
if (is_blx && (sym_addr & 1))
return grub_error (GRUB_ERR_BAD_MODULE,
N_("Relocation targeting wrong execution state"));
offset_low = -16777216;
offset_high = is_blx ? 16777212 : 16777214;
/* Extract bitfields from instruction words */
sign = (insword >> 26) & 1;
j1 = (insword >> 13) & 1;
j2 = (insword >> 11) & 1;
offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
((~(j2 ^ sign) & 1) << 22) |
((insword & 0x03ff0000) >> 4) | ((insword & 0x000007ff) << 1);
/* Sign adjust and calculate offset */
if (offset & (1 << 24))
offset -= (1 << 25);
grub_dprintf ("dl", " sym_addr = 0x%08x", sym_addr);
offset += sym_addr;
#ifndef GRUB_UTIL
offset -= (grub_uint32_t) target;
#endif
grub_dprintf("dl", " %s: target=%p, sym_addr=0x%08x, offset=%d\n",
is_blx ? "BLX" : "BL", target, sym_addr, offset);
if ((offset < offset_low) || (offset > offset_high))
return grub_error (GRUB_ERR_BAD_MODULE,
N_("THM_CALL Relocation out of range."));
grub_dprintf ("dl", " relative destination = 0x%08lx",
(unsigned long)target + offset);
/* Reassemble instruction word */
sign = (offset >> 24) & 1;
j1 = sign ^ (~(offset >> 23) & 1);
j2 = sign ^ (~(offset >> 22) & 1);
insword = (insword & insmask) |
(sign << 26) |
(((offset >> 12) & 0x03ff) << 16) |
(j1 << 13) | (j2 << 11) | ((offset >> 1) & 0x07ff);
/* Write instruction word back in alignment-safe manner */
*target = grub_cpu_to_le16 ((insword >> 16) & 0xffff);
*(target + 1) = grub_cpu_to_le16 (insword & 0xffff);
grub_dprintf ("dl", " *insword = 0x%08x", insword);
return GRUB_ERR_NONE;
}
/*
* R_ARM_THM_JUMP19
*
* Relocate conditional Thumb (T32) B.W
*/
grub_err_t
grub_arm_reloc_thm_jump19 (grub_uint16_t *target, Elf32_Addr sym_addr)
{
grub_int32_t offset;
grub_uint32_t insword, insmask;
/* Extract instruction word in alignment-safe manner */
insword = grub_le_to_cpu16 ((*target)) << 16
| grub_le_to_cpu16 (*(target + 1));
insmask = 0xfbc0d000;
/* Extract and sign extend offset */
offset = ((insword >> 26) & 1) << 19
| ((insword >> 11) & 1) << 18
| ((insword >> 13) & 1) << 17
| ((insword >> 16) & 0x3f) << 11
| (insword & 0x7ff);
offset <<= 1;
if (offset & (1 << 20))
offset -= (1 << 21);
/* Adjust and re-truncate offset */
offset += sym_addr;
#ifndef GRUB_UTIL
offset -= (grub_uint32_t) target;
#endif
if ((offset > 1048574) || (offset < -1048576))
return grub_error (GRUB_ERR_BAD_MODULE,
N_("THM_JUMP19 Relocation out of range."));
offset >>= 1;
offset &= 0xfffff;
/* Reassemble instruction word and write back */
insword &= insmask;
insword |= ((offset >> 19) & 1) << 26
| ((offset >> 18) & 1) << 11
| ((offset >> 17) & 1) << 13
| ((offset >> 11) & 0x3f) << 16
| (offset & 0x7ff);
*target = grub_cpu_to_le16 (insword >> 16);
*(target + 1) = grub_cpu_to_le16 (insword & 0xffff);
return GRUB_ERR_NONE;
}
/***********************************************************
* ARM (A32) relocations: *
* *
* ARM instructions are 32-bit in size and 32-bit aligned. *
***********************************************************/
/*
* R_ARM_JUMP24
*
* Relocate ARM (A32) B
*/
grub_err_t
grub_arm_reloc_jump24 (grub_uint32_t *target, Elf32_Addr sym_addr)
{
grub_uint32_t insword;
grub_int32_t offset;
if (sym_addr & 1)
return grub_error (GRUB_ERR_BAD_MODULE,
N_("Relocation targeting wrong execution state"));
insword = grub_le_to_cpu32 (*target);
offset = (insword & 0x00ffffff) << 2;
if (offset & 0x02000000)
offset -= 0x04000000;
offset += sym_addr;
#ifndef GRUB_UTIL
offset -= (grub_uint32_t) target;
#endif
insword &= 0xff000000;
insword |= (offset >> 2) & 0x00ffffff;
*target = grub_cpu_to_le32 (insword);
return GRUB_ERR_NONE;
}