222 lines
6.3 KiB
C
222 lines
6.3 KiB
C
/* dl.c - arch-dependent part of loadable module support */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2013 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/dl.h>
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#include <grub/elf.h>
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#include <grub/misc.h>
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#include <grub/err.h>
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#include <grub/mm.h>
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#include <grub/i18n.h>
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#include <grub/arm/reloc.h>
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/*
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* R_ARM_ABS32
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*
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* Simple relocation of 32-bit value (in literal pool)
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*/
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grub_err_t
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grub_arm_reloc_abs32 (Elf32_Word *target, Elf32_Addr sym_addr)
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{
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Elf32_Addr tmp;
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tmp = grub_le_to_cpu32 (*target);
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tmp += sym_addr;
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*target = grub_cpu_to_le32 (tmp);
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grub_dprintf ("dl", " %s: reloc_abs32 0x%08x => 0x%08x", __FUNCTION__,
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(unsigned int) sym_addr, (unsigned int) tmp);
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return GRUB_ERR_NONE;
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}
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/********************************************************************
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* Thumb (T32) relocations: *
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* *
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* 32-bit Thumb instructions can be 16-bit aligned, and are fetched *
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* little-endian, requiring some additional fiddling. *
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********************************************************************/
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/*
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* R_ARM_THM_CALL/THM_JUMP24
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*
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* Relocate Thumb (T32) instruction set relative branches:
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* B.W, BL and BLX
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*/
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grub_err_t
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grub_arm_reloc_thm_call (grub_uint16_t *target, Elf32_Addr sym_addr)
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{
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grub_int32_t offset, offset_low, offset_high;
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grub_uint32_t sign, j1, j2, is_blx;
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grub_uint32_t insword, insmask;
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/* Extract instruction word in alignment-safe manner */
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insword = (grub_le_to_cpu16 (*target) << 16)
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| (grub_le_to_cpu16(*(target + 1)));
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insmask = 0xf800d000;
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/* B.W/BL or BLX? Affects range and expected target state */
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if (((insword >> 12) & 0xd) == 0xc)
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is_blx = 1;
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else
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is_blx = 0;
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/* If BLX, target symbol must be ARM (target address LSB == 0) */
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if (is_blx && (sym_addr & 1))
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return grub_error (GRUB_ERR_BAD_MODULE,
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N_("Relocation targeting wrong execution state"));
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offset_low = -16777216;
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offset_high = is_blx ? 16777212 : 16777214;
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/* Extract bitfields from instruction words */
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sign = (insword >> 26) & 1;
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j1 = (insword >> 13) & 1;
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j2 = (insword >> 11) & 1;
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offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
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((~(j2 ^ sign) & 1) << 22) |
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((insword & 0x03ff0000) >> 4) | ((insword & 0x000007ff) << 1);
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/* Sign adjust and calculate offset */
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if (offset & (1 << 24))
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offset -= (1 << 25);
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grub_dprintf ("dl", " sym_addr = 0x%08x", sym_addr);
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offset += sym_addr;
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#ifndef GRUB_UTIL
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offset -= (grub_uint32_t) target;
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#endif
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grub_dprintf("dl", " %s: target=%p, sym_addr=0x%08x, offset=%d\n",
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is_blx ? "BLX" : "BL", target, sym_addr, offset);
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if ((offset < offset_low) || (offset > offset_high))
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return grub_error (GRUB_ERR_BAD_MODULE,
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N_("THM_CALL Relocation out of range."));
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grub_dprintf ("dl", " relative destination = 0x%08lx",
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(unsigned long)target + offset);
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/* Reassemble instruction word */
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sign = (offset >> 24) & 1;
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j1 = sign ^ (~(offset >> 23) & 1);
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j2 = sign ^ (~(offset >> 22) & 1);
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insword = (insword & insmask) |
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(sign << 26) |
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(((offset >> 12) & 0x03ff) << 16) |
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(j1 << 13) | (j2 << 11) | ((offset >> 1) & 0x07ff);
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/* Write instruction word back in alignment-safe manner */
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*target = grub_cpu_to_le16 ((insword >> 16) & 0xffff);
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*(target + 1) = grub_cpu_to_le16 (insword & 0xffff);
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grub_dprintf ("dl", " *insword = 0x%08x", insword);
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return GRUB_ERR_NONE;
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}
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/*
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* R_ARM_THM_JUMP19
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*
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* Relocate conditional Thumb (T32) B<c>.W
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*/
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grub_err_t
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grub_arm_reloc_thm_jump19 (grub_uint16_t *target, Elf32_Addr sym_addr)
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{
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grub_int32_t offset;
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grub_uint32_t insword, insmask;
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/* Extract instruction word in alignment-safe manner */
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insword = grub_le_to_cpu16 ((*target)) << 16
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| grub_le_to_cpu16 (*(target + 1));
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insmask = 0xfbc0d000;
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/* Extract and sign extend offset */
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offset = ((insword >> 26) & 1) << 19
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| ((insword >> 11) & 1) << 18
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| ((insword >> 13) & 1) << 17
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| ((insword >> 16) & 0x3f) << 11
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| (insword & 0x7ff);
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offset <<= 1;
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if (offset & (1 << 20))
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offset -= (1 << 21);
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/* Adjust and re-truncate offset */
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offset += sym_addr;
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#ifndef GRUB_UTIL
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offset -= (grub_uint32_t) target;
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#endif
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if ((offset > 1048574) || (offset < -1048576))
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return grub_error (GRUB_ERR_BAD_MODULE,
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N_("THM_JUMP19 Relocation out of range."));
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offset >>= 1;
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offset &= 0xfffff;
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/* Reassemble instruction word and write back */
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insword &= insmask;
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insword |= ((offset >> 19) & 1) << 26
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| ((offset >> 18) & 1) << 11
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| ((offset >> 17) & 1) << 13
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| ((offset >> 11) & 0x3f) << 16
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| (offset & 0x7ff);
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*target = grub_cpu_to_le16 (insword >> 16);
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*(target + 1) = grub_cpu_to_le16 (insword & 0xffff);
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return GRUB_ERR_NONE;
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}
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/***********************************************************
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* ARM (A32) relocations: *
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* *
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* ARM instructions are 32-bit in size and 32-bit aligned. *
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***********************************************************/
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/*
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* R_ARM_JUMP24
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*
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* Relocate ARM (A32) B
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*/
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grub_err_t
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grub_arm_reloc_jump24 (grub_uint32_t *target, Elf32_Addr sym_addr)
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{
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grub_uint32_t insword;
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grub_int32_t offset;
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if (sym_addr & 1)
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return grub_error (GRUB_ERR_BAD_MODULE,
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N_("Relocation targeting wrong execution state"));
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insword = grub_le_to_cpu32 (*target);
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offset = (insword & 0x00ffffff) << 2;
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if (offset & 0x02000000)
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offset -= 0x04000000;
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offset += sym_addr;
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#ifndef GRUB_UTIL
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offset -= (grub_uint32_t) target;
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#endif
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insword &= 0xff000000;
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insword |= (offset >> 2) & 0x00ffffff;
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*target = grub_cpu_to_le32 (insword);
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return GRUB_ERR_NONE;
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}
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