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/*
* relocate - common relocation function for ARM U-Boot
*
* Copyright (c) 2013 Albert ARIBAUD <albert.u.boot@aribaud.net>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program 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 2 of
* the License, or (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <linux/linkage.h>
/*
* void relocate_code(addr_moni)
*
* This function relocates the monitor code.
*
* NOTE:
* To prevent the code below from containing references with an R_ARM_ABS32
* relocation record type, we never refer to linker-defined symbols directly.
* Instead, we declare literals which contain their relative location with
* respect to relocate_code, and at run time, add relocate_code back to them.
*/
ENTRY(relocate_code)
mov r6, r0 /* save addr of destination */
ldr r0, =_start /* r0 <- SRC &_start */
subs r9, r6, r0 /* r9 <- relocation offset */
beq relocate_done /* skip relocation */
mov r1, r6 /* r1 <- scratch for copy loop */
adr r7, relocate_code /* r7 <- SRC &relocate_code */
ldr r3, _image_copy_end_ofs /* r3 <- __image_copy_end local ofs */
add r2, r7, r3 /* r2 <- SRC &__image_copy_end */
copy_loop:
ldmia r0!, {r10-r11} /* copy from source address [r0] */
stmia r1!, {r10-r11} /* copy to target address [r1] */
cmp r0, r2 /* until source end address [r2] */
blo copy_loop
/*
* fix .rel.dyn relocations
*/
ldr r10, _dynsym_start_ofs /* r10 <- __dynsym_start local ofs */
add r10, r10, r7 /* r10 <- SRC &__dynsym_start */
ldr r2, _rel_dyn_start_ofs /* r2 <- __rel_dyn_start local ofs */
add r2, r2, r7 /* r2 <- SRC &__rel_dyn_start */
ldr r3, _rel_dyn_end_ofs /* r3 <- __rel_dyn_end local ofs */
add r3, r3, r7 /* r3 <- SRC &__rel_dyn_end */
fixloop:
ldr r0, [r2] /* r0 <- SRC location to fix up */
add r0, r0, r9 /* r0 <- DST location to fix up */
ldr r1, [r2, #4]
and r7, r1, #0xff
cmp r7, #23 /* relative fixup? */
beq fixrel
cmp r7, #2 /* absolute fixup? */
beq fixabs
/* ignore unknown type of fixup */
b fixnext
fixabs:
/* absolute fix: set location to (offset) symbol value */
mov r1, r1, LSR #4 /* r1 <- symbol index in .dynsym */
add r1, r10, r1 /* r1 <- address of symbol in table */
ldr r1, [r1, #4] /* r1 <- symbol value */
add r1, r1, r9 /* r1 <- relocated sym addr */
b fixnext
fixrel:
/* relative fix: increase location by offset */
ldr r1, [r0]
add r1, r1, r9
fixnext:
str r1, [r0]
add r2, r2, #8 /* each rel.dyn entry is 8 bytes */
cmp r2, r3
blo fixloop
relocate_done:
/* ARMv4- don't know bx lr but the assembler fails to see that */
#ifdef __ARM_ARCH_4__
mov pc, lr
#else
bx lr
#endif
_image_copy_end_ofs:
.word __image_copy_end - relocate_code
_rel_dyn_start_ofs:
.word __rel_dyn_start - relocate_code
_rel_dyn_end_ofs:
.word __rel_dyn_end - relocate_code
_dynsym_start_ofs:
.word __dynsym_start - relocate_code
ENDPROC(relocate_code)
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