minix/libexec/ld.elf_so/arch/arm/rtld_start.S

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/* $NetBSD: rtld_start.S,v 1.11 2012/08/13 02:53:25 matt Exp $ */
/*-
* Copyright (c) 1998, 2002 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas and by Charles M. Hannum.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <machine/asm.h>
RCSID("$NetBSD: rtld_start.S,v 1.11 2012/08/13 02:53:25 matt Exp $")
.text
.align 0
.globl _rtld_start
.type _rtld_start,%function
_rtld_start:
sub sp, sp, #8 /* make room for obj_main & exit proc */
mov r4, r0 /* save ps_strings */
ldr sl, .L2
ldr r5, .L2+4
ldr r0, .L2+8
.L1:
add sl, pc, sl
ldr r5, [sl, r5]
ldr r0, [sl, r0]
sub r1, sl, r5 /* relocbase */
add r0, r1, r0 /* &_DYNAMIC */
bl _rtld_relocate_nonplt_self
sub r1, sl, r5 /* relocbase */
mov r0, sp /* sp */
bl _rtld /* call the shared loader */
mov r3, r0 /* save entry point */
ldr r2, [sp], #4 /* pop r2 = cleanup */
ldr r1, [sp], #4 /* pop r1 = obj_main */
mov r0, r4 /* restore ps_strings */
#ifdef _ARM_ARCH_4T
bx r3 /* jump to the entry point */
#else
mov pc, r3 /* jump to the entry point */
#endif
.L2:
.word _GLOBAL_OFFSET_TABLE_ - (.L1+8)
.word _GLOBAL_OFFSET_TABLE_(GOT)
.word _DYNAMIC(GOT)
.align 0
.globl _rtld_bind_start
.type _rtld_bind_start,%function
/*
* stack[0] = RA
* ip = &GOT[n+3]
* lr = &GOT[2]
*/
_rtld_bind_start:
stmdb sp!,{r0-r4,sl,fp} /* 8 byte aligned (lr already saved) */
sub r1, ip, lr /* r1 = 4 * (n + 1) */
sub r1, r1, #4 /* r1 = 4 * n */
add r1, r1, r1 /* r1 = 8 * n */
ldr r0, [lr, #-4] /* get obj ptr from GOT[1] */
mov r4, ip /* save GOT location */
bl _rtld_bind /* Call the binder */
str r0, [r4] /* save address in GOT */
mov ip, r0 /* save new address */
ldmia sp!,{r0-r4,sl,fp,lr} /* restore the stack */
#ifdef _ARM_ARCH_4T
bx ip /* jump to the new address */
#else
mov pc, ip /* jump to the new address */
#endif