freebsd-dev/libexec/rtld-elf/arm/rtld_start.S
Konstantin Belousov 96cdb0ab9d Annotate arm userspace assembler sources stating their tolerance to
the non-executable stack.

Reviewed by:	andrew
Sponsored by:	The FreeBSD Foundation
2015-09-29 16:09:58 +00:00

101 lines
3.2 KiB
ArmAsm

/* $NetBSD: rtld_start.S,v 1.7 2002/09/12 17:18:38 mycroft 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>
__FBSDID("$FreeBSD$");
.text
.align 0
.globl .rtld_start
.type .rtld_start,%function
.rtld_start:
mov r6, sp /* save the stack pointer */
bic sp, sp, #7 /* align the stack pointer */
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
mov r1, sp
add r2, sp, #4
mov r0, r6 /* load the sp the kernel gave us */
bl _rtld /* call the shared loader */
mov r3, r0 /* save entry point */
ldr r2, [sp, #0] /* r2 = cleanup */
ldr r1, [sp, #4] /* r1 = obj_main */
mov sp, r6 /* restore stack */
mov r0, r4 /* restore ps_strings */
mov pc, r3 /* jump to the entry point */
.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-r5,sl,fp}
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 */
mov r5, sp /* Save the stack pointer */
bic sp, sp, #7 /* Align the stack pointer */
bl _rtld_bind /* Call the binder */
mov sp, r5 /* Restore the old stack pointer */
str r0, [r4] /* save address in GOT */
mov ip, r0 /* save new address */
ldmia sp!,{r0-r5,sl,fp,lr} /* restore the stack */
mov pc, ip /* jump to the new address */
.section .note.GNU-stack,"",%progbits