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rtld_start.S revision 1.14 
      1 /*	$NetBSD: rtld_start.S,v 1.14 2011/01/16 01:22:29 matt Exp $	*/
      2 
      3 /*-
      4  * Copyright (C) 1998	Tsubai Masanari
      5  * Portions copyright 2002 Charles M. Hannum <root (at) ihack.net>
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. The name of the author may not be used to endorse or promote products
     17  *    derived from this software without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include <machine/asm.h>
     32 
     33 	.globl	_rtld_start
     34 	.globl	_rtld
     35 
     36 	.text
     37 
     38 _rtld_start:
     39 	stwu	%r1,-48(%r1)
     40 	stw	%r3,12(%r1)		# argc
     41 	stw	%r4,16(%r1)		# argv
     42 	stw	%r5,20(%r1)		# envp
     43 /*	stw	%r6,24(%r1)		# obj		(always 0) */
     44 /*	stw	%r7,28(%r1)		# cleanup	(always 0) */
     45 	stw	%r8,32(%r1)		# ps_strings
     46 
     47 	bcl	20,31,1f
     48 1:	mflr	%r30
     49 	mr	%r3,%r30		# save for _DYNAMIC
     50 	addis	%r30,%r30,_GLOBAL_OFFSET_TABLE_-1b@ha
     51 	addi	%r30,%r30,_GLOBAL_OFFSET_TABLE_-1b@l
     52 	addis	%r3,%r3,_DYNAMIC-1b@ha	# get _DYNAMIC actual address
     53 	addi	%r3,%r3,_DYNAMIC-1b@l
     54 	lwz	%r28,0(%r30)		# get base-relative &_DYNAMIC
     55 	sub	%r28,%r3,%r28		# r28 = relocbase
     56 	mr	%r4,%r28		# r4 = relocbase
     57 	bl	_rtld_relocate_nonplt_self
     58 
     59 	lwz	%r3,16(%r1)
     60 	addi	%r3,%r3,-12		# sp = &argv[-3]	/* XXX */
     61 	mr	%r4,%r28		# r4 = relocbase
     62 	bl	_rtld			# _start = _rtld(sp, relocbase)
     63 	mtlr	%r3
     64 
     65 	lwz	%r3,12(%r1)		# argc
     66 	lwz	%r4,16(%r1)		# argv
     67 	lwz	%r5,20(%r1)		# envp
     68 	lwz	%r6,-8(%r4)		# obj = sp[1] (== argv[-2])
     69 	lwz	%r7,-12(%r4)		# cleanup = sp[0] (== argv[-3])
     70 	lwz	%r8,32(%r1)		# ps_strings
     71 
     72 	addi	%r1,%r1,48
     73 	blrl		# _start(argc, argv, envp, obj, cleanup, ps_strings)
     74 
     75 	li	%r0,1			# _exit()
     76 	sc
     77 
     78 END(_rtld_start)
     79 
     80 	.globl	_rtld_bind
     81 
     82 /*
     83  * secure-plt expects %r11 to be the offset to the rela entry.
     84  * bss-plt expects %r11 to be index of the rela entry.
     85  * So for bss-plt, we multiply the index by 12 to get the offset.
     86  */
     87 ENTRY_NOPROFILE(_rtld_bind_bssplt_start)
     88 	slwi	%r11,%r11,2
     89 	add	%r0,%r11,%r11
     90 	add	%r11,%r11,%r0
     91 ENTRY_NOPROFILE(_rtld_bind_secureplt_start)
     92 	stwu	%r1,-160(%r1)
     93 
     94 	stw	%r0,20(%r1)
     95 	mflr	%r0
     96 	stw	%r0,16(%r1)		# save lr
     97 	mfcr	%r0
     98 	stw	%r0,12(%r1)		# save cr
     99 	stmw	%r3,24(%r1)		# save r3-r31
    100 
    101 	mr	%r3,%r12		# obj
    102 	mr	%r4,%r11		# reloff
    103 	bl	_rtld_bind		# _rtld_bind(obj, reloff)
    104 	mtctr	%r3
    105 
    106 	lmw	%r3,24(%r1)		# load r3-r31
    107 	lwz	%r0,12(%r1)		# restore cr
    108 	mtcr	%r0
    109 	lwz	%r0,16(%r1)		# restore lr
    110 	mtlr	%r0
    111 	lwz	%r0,20(%r1)
    112 
    113 	addi	%r1,%r1,160
    114 	bctr
    115 END(_rtld_bind_start)
    116 
    117 	.globl	_rtld_powerpc_pltcall
    118 	.globl	_rtld_powerpc_pltresolve
    119 
    120 _rtld_powerpc_pltcall:
    121 	slwi	%r11,%r11,2
    122 	addis	%r11,%r11,0		# addis	11,11,jmptab@ha
    123 	lwz	%r11,0(%r11)		# lwz	11,jmptab@l(11)
    124 	mtctr	%r11
    125 	bctr
    126 
    127 _rtld_powerpc_pltresolve:
    128 	lis	%r12,0			# lis	12,_rtld_bind_bssplt_start@ha
    129 	addi	%r12,%r12,0		# addi	12,12,_rtld_bind_bssplt_start@l
    130 	mtctr	%r12
    131 	lis	%r12,0			# lis	12,obj@ha
    132 	addi	%r12,%r12,0		# addi	12,12,obj@l
    133 	bctr
    134