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/* $NetBSD: rtld_start.S,v 1.4 2001/09/26 04:06:43 mycroft Exp $ */
/*-
* Copyright (C) 1998 Tsubai Masanari
* All rights reserved.
*
* 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
* $FreeBSD$
*/
#include <machine/asm.h>
.extern _GLOBAL_OFFSET_TABLE_
.extern _DYNAMIC
_ENTRY(_rtld_start)
stdu %r1,-144(%r1) /* 16-byte aligned stack for reg saves +
exit_proc & obj _rtld args +
backchain & lrsave stack frame */
std %r3,96(%r1) /* argc */
std %r4,104(%r1) /* argv */
std %r5,112(%r1) /* envp */
/* std %r6,120(%r1) *//* obj (always 0) */
/* std %r7,128(%r1) *//* cleanup (always 0) */
std %r8,136(%r1) /* ps_strings */
/*
* Perform initial relocation of ld-elf.so. Not as easy as it
* sounds.
* - perform small forward branch to put PC into link reg
* - use link-time constants to determine offset to the
* _DYNAMIC section and the GOT. Add these to the PC to
* convert to absolute addresses.
* - call reloc_non_plt_self() to fix up ld-elf.so's relocations
*/
bl 1f
.llong _DYNAMIC-.
1:
mflr %r3 /* PC value at .llong */
ld %r4,0(%r3) /* offset to _DYNAMIC */
add %r3,%r4,%r3 /* r3 = &_DYNAMIC, absolute value */
ld %r4,-0x8000(%r2) /* First TOC entry is TOC base */
subf %r4,%r4,%r2 /* Subtract from real TOC base to get base */
bl reloc_non_plt_self /* reloc_non_plt_self(&_DYNAMIC,base) */
nop
/*
* The _rtld() function likes to see a stack layout containing
* { argc, argv[0], argv[1] ... argv[N], 0, env[0], ... , env[N] }
* Since the PowerPC stack was 16-byte aligned at exec time, the
* original stack layout has to be found by moving back a word
* from the argv pointer.
*/
ld %r4,104(%r1)
addi %r3,%r4,-8 /* locate argc ptr, &argv[-1] */
addi %r4,%r1,128 /* &exit_proc on stack */
addi %r5,%r1,120 /* &obj_main on stack */
bl _rtld /* &_start = _rtld(sp, &exit_proc, &obj_main)*/
nop
#if !defined(_CALL_ELF) || _CALL_ELF == 1
ld %r2,8(%r3)
ld %r11,16(%r3)
ld %r3,0(%r3)
#else
mr %r12,%r3
#endif
mtlr %r3
/*
* Restore args, with new obj/exit proc
*/
ld %r3,96(%r1) /* argc */
ld %r4,104(%r1) /* argv */
ld %r5,112(%r1) /* envp */
ld %r6,120(%r1) /* obj */
ld %r7,128(%r1) /* exit proc */
ld %r8,136(%r1) /* ps_strings */
blrl /* _start(argc, argv, envp, obj, cleanup, ps_strings) */
li %r0,1 /* _exit() */
sc
/*
* _rtld_bind_start()
*
* Call into the MI binder. This routine is reached via the PLT call cell
*
* On entry, %r11 contains an object pointer and %r0 contains the PLT index.
*
* Save all registers, call into the binder to resolve and fixup the external
* routine, and then transfer to the external routine on return.
*/
.globl _rtld_bind
_ENTRY(_rtld_bind_start)
mr %r12,%r0 # save r0 (index) immediately to r12
mflr %r0
std %r0,16(%r1) # save lr
mfcr %r0
std %r0,8(%r1) # save cr
stdu %r1,-48-12*8(%r1) # stack space for 8 regs + header
# + 2 save regs
std %r3,64+0*8(%r1) # save r3-r10 (arguments)
std %r4,64+1*8(%r1)
std %r5,64+2*8(%r1)
std %r6,64+3*8(%r1)
std %r7,64+4*8(%r1)
std %r8,64+5*8(%r1)
std %r9,64+6*8(%r1)
std %r10,64+7*8(%r1)
mr %r3,%r11
mulli %r4,%r12,24 # Multiply index by sizeof(Elf_Rela)
bl _rtld_bind # target addr = _rtld_bind(obj, reloff)
nop
#if !defined(_CALL_ELF) || _CALL_ELF == 1
ld %r2,8(%r3)
ld %r11,16(%r3)
ld %r3,0(%r3)
#else
mr %r12,%r3
#endif
mtctr %r3 # move absolute target addr into ctr
ld %r3,64+0*8(%r1) # restore r3-r10
ld %r4,64+1*8(%r1)
ld %r5,64+2*8(%r1)
ld %r6,64+3*8(%r1)
ld %r7,64+4*8(%r1)
ld %r8,64+5*8(%r1)
ld %r9,64+6*8(%r1)
ld %r10,64+7*8(%r1)
ld %r1,0(%r1) # restore stack
ld %r0,8(%r1) # restore cr
mtcr %r0
ld %r0,16(%r1) # restore lr
mtlr %r0
bctr # jump to target
.section .note.GNU-stack,"",%progbits
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