163 lines
4.9 KiB
ArmAsm
163 lines
4.9 KiB
ArmAsm
/* $NetBSD: rtld_start.S,v 1.4 2001/09/26 04:06:43 mycroft Exp $ */
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/*-
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* Copyright (C) 1998 Tsubai Masanari
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <machine/asm.h>
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.extern _GLOBAL_OFFSET_TABLE_
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.extern _DYNAMIC
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_ENTRY(_rtld_start)
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stdu %r1,-144(%r1) /* 16-byte aligned stack for reg saves +
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exit_proc & obj _rtld args +
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backchain & lrsave stack frame */
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std %r3,96(%r1) /* argc */
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std %r4,104(%r1) /* argv */
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std %r5,112(%r1) /* envp */
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/* std %r6,120(%r1) *//* obj (always 0) */
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/* std %r7,128(%r1) *//* cleanup (always 0) */
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std %r8,136(%r1) /* ps_strings */
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/*
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* Perform initial relocation of ld-elf.so. Not as easy as it
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* sounds.
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* - perform small forward branch to put PC into link reg
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* - use link-time constants to determine offset to the
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* _DYNAMIC section and the GOT. Add these to the PC to
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* convert to absolute addresses.
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* - call reloc_non_plt_self() to fix up ld-elf.so's relocations
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*/
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bl 1f
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.llong _DYNAMIC-.
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1:
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mflr %r3 /* PC value at .llong */
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ld %r4,0(%r3) /* offset to _DYNAMIC */
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add %r3,%r4,%r3 /* r3 = &_DYNAMIC, absolute value */
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ld %r4,-0x8000(%r2) /* First TOC entry is TOC base */
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subf %r4,%r4,%r2 /* Subtract from real TOC base to get base */
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bl reloc_non_plt_self /* reloc_non_plt_self(&_DYNAMIC,base) */
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nop
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/*
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* The _rtld() function likes to see a stack layout containing
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* { argc, argv[0], argv[1] ... argv[N], 0, env[0], ... , env[N] }
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* Since the PowerPC stack was 16-byte aligned at exec time, the
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* original stack layout has to be found by moving back a word
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* from the argv pointer.
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*/
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ld %r4,104(%r1)
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addi %r3,%r4,-8 /* locate argc ptr, &argv[-1] */
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addi %r4,%r1,128 /* &exit_proc on stack */
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addi %r5,%r1,120 /* &obj_main on stack */
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bl _rtld /* &_start = _rtld(sp, &exit_proc, &obj_main)*/
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nop
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ld %r2,8(%r3)
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ld %r11,16(%r3)
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ld %r3,0(%r3)
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mtlr %r3
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/*
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* Restore args, with new obj/exit proc
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*/
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ld %r3,96(%r1) /* argc */
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ld %r4,104(%r1) /* argv */
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ld %r5,112(%r1) /* envp */
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ld %r6,120(%r1) /* obj */
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ld %r7,128(%r1) /* exit proc */
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ld %r8,136(%r1) /* ps_strings */
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blrl /* _start(argc, argv, envp, obj, cleanup, ps_strings) */
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li %r0,1 /* _exit() */
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sc
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/*
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* _rtld_bind_start()
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*
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* Call into the MI binder. This routine is reached via the PLT call cell
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* On entry, %r11 contains a pointer to the (object, relocation) tuple.
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*
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* Save all registers, call into the binder to resolve and fixup the external
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* routine, and then transfer to the external routine on return.
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*/
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.globl _rtld_bind
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_ENTRY(_rtld_bind_start)
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mflr %r0
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std %r0,16(%r1) # save lr
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mfcr %r0
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std %r0,8(%r1) # save cr
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stdu %r1,-48-12*8(%r1) # stack space for 8 regs + header
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# + 2 save regs
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std %r3,64+0*8(%r1) # save r3-r31
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std %r4,64+1*8(%r1)
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std %r5,64+2*8(%r1)
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std %r6,64+3*8(%r1)
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std %r7,64+4*8(%r1)
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std %r8,64+5*8(%r1)
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std %r9,64+6*8(%r1)
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std %r10,64+7*8(%r1)
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std %r12,64+8*8(%r1)
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ld %r3,0(%r11)
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ld %r4,8(%r11)
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bl _rtld_bind # target addr = _rtld_bind(obj, reloff)
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nop
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ld %r2,8(%r3)
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ld %r11,16(%r3)
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ld %r3,0(%r3)
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mtctr %r3 # move absolute target addr into ctr
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ld %r3,64+0*8(%r1) # restore r3-r31
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ld %r4,64+1*8(%r1)
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ld %r5,64+2*8(%r1)
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ld %r6,64+3*8(%r1)
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ld %r7,64+4*8(%r1)
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ld %r8,64+5*8(%r1)
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ld %r9,64+6*8(%r1)
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ld %r10,64+7*8(%r1)
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ld %r12,64+8*8(%r1)
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ld %r1,0(%r1) # restore stack
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ld %r0,8(%r1) # restore cr
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mtcr %r0
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ld %r0,16(%r1) # restore lr
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mtlr %r0
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bctr # jump to target
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.section .note.GNU-stack,"",%progbits
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