201 lines
7.2 KiB
ArmAsm
201 lines
7.2 KiB
ArmAsm
/* $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)
|
|
stwu %r1,-48(%r1) /* 16-byte aligned stack for reg saves +
|
|
exit_proc & obj _rtld args +
|
|
backchain & lrsave stack frame */
|
|
stw %r3,16(%r1) /* argc */
|
|
stw %r4,20(%r1) /* argv */
|
|
stw %r5,24(%r1) /* envp */
|
|
/* stw %r6,28(%r1) *//* obj (always 0) */
|
|
/* stw %r7,32(%r1) *//* cleanup (always 0) */
|
|
stw %r8,36(%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.
|
|
* - sync icache to allow execution of the SVR4 ABI-specified
|
|
* blrl instruction preceding the GOT
|
|
* - Use this instruction to determine the GOT absolute address
|
|
* - read GOT[0], which is the SVR4 ABI-specified link-time
|
|
* value of _DYNAMIC. Subtract this value from the absolute
|
|
* value to determine the load address
|
|
* - call reloc_non_plt_self() to fix up ld-elf.so's relocations
|
|
*/
|
|
bl 1f
|
|
.long _DYNAMIC-.
|
|
.long _GLOBAL_OFFSET_TABLE_-. /* branch lr + 4 */
|
|
1:
|
|
mflr %r3 /* PC value at .long */
|
|
lwz %r4,4(%r3)
|
|
add %r4,%r4,%r3 /* &_GLOBAL_OFFSET_TABLE-4, blrl insn. */
|
|
dcbst %r0,%r4 /* sync i-cache with d-cache */
|
|
sync
|
|
icbi %r0,%r4
|
|
isync
|
|
|
|
lwz %r4,0(%r3) /* offset to _DYNAMIC */
|
|
add %r3,%r4,%r3 /* r3 = &_DYNAMIC, absolute value */
|
|
|
|
bl _GLOBAL_OFFSET_TABLE_@local-4
|
|
mflr %r4 /* &_GLOBAL_OFFSET_TABLE_, absolute value */
|
|
lwz %r4,0(%r4) /* linker &_DYNAMIC, from got[0] */
|
|
subf %r4,%r4,%r3 /* subtract to calculate relocbase */
|
|
|
|
bl reloc_non_plt_self@plt /* reloc_non_plt_self(&_DYNAMIC,base) */
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
lwz %r4,20(%r1) /* restore argv */
|
|
addi %r3,%r4,-4 /* locate argc ptr, &argv[-1] */
|
|
|
|
addi %r4,%r1,8 /* &exit_proc on stack */
|
|
addi %r5,%r1,12 /* &obj_main on stack */
|
|
|
|
bl _rtld@plt /* &_start = _rtld(sp, &exit_proc, &obj_main)*/
|
|
mtlr %r3
|
|
|
|
/*
|
|
* Restore args, with new obj/exit proc
|
|
*/
|
|
lwz %r3,16(%r1) /* argc */
|
|
lwz %r4,20(%r1) /* argv */
|
|
lwz %r5,24(%r1) /* envp */
|
|
lwz %r6,12(%r1) /* obj */
|
|
lwz %r7,8(%r1) /* exit proc */
|
|
lwz %r8,36(%r1) /* ps_strings */
|
|
addi %r1,%r1,48 /* restore original stackptr */
|
|
|
|
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,
|
|
* and then _rtld_powerpc_pltresolve().
|
|
* On entry, %r11 contains the index of the PLT cell, and %r12 contains
|
|
* a pointer to the ELF object for the file.
|
|
* 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)
|
|
stwu %r1,-160(%r1) # stack space for 29 regs + r0/lr/cr
|
|
stw %r0,20(%r1) # save r0
|
|
mflr %r0
|
|
stw %r0,16(%r1) # save lr
|
|
mfcr %r0
|
|
stw %r0,12(%r1) # save cr
|
|
stmw %r3,24(%r1) # save r3-r31
|
|
|
|
mr %r3,%r12 # obj
|
|
mulli %r4,%r11,12 # rela index * sizeof(Elf_Rela)
|
|
bl _rtld_bind@PLT # target addr = _rtld_bind(obj, reloff)
|
|
mtctr %r3 # move absolute target addr into ctr
|
|
|
|
lmw %r3,24(%r1) # restore r3-r31
|
|
lwz %r0,12(%r1) # restore cr
|
|
mtcr %r0
|
|
lwz %r0,16(%r1) # restore lr
|
|
mtlr %r0
|
|
lwz %r0,20(%r1) # restore r0
|
|
|
|
addi %r1,%r1,160 # restore stack
|
|
bctr # jump to target
|
|
|
|
|
|
/*
|
|
* _rtld_powerpc_pltresolve()
|
|
*
|
|
* This routine is copied into the latter part of the 72-byte reserved
|
|
* area at the start of the PLT. The absolute address of the _rtld_bind_start
|
|
* routine, and the ELF object for the loaded file, are inserted into
|
|
* the code by the reloc.c:init_pltgot() routine.
|
|
* The first time an external routine is called, the PLT slot will
|
|
* set up %r11 to the offset of the slot, and will jump to this routine.
|
|
* The ELF object is shifted into %r11, and _rtld_bind_start is called
|
|
* to complete the binding.
|
|
*/
|
|
_ENTRY(_rtld_powerpc_pltlongresolve)
|
|
lis %r12,0 # lis 12,jmptab@ha
|
|
addi %r12,%r12,0 # addi 12,12,jmptab@l
|
|
subf %r11,%r12,%r11 # reloff
|
|
li %r12,2
|
|
srw %r11,%r11,%r12 # index = reloff/sizeof(Elf_Addr)
|
|
_ENTRY(_rtld_powerpc_pltresolve)
|
|
lis %r12,0 # lis 12,_rtld_bind_start@ha
|
|
addi %r12,%r12,0 # addi 12,12,_rtld_bind_start@l
|
|
mtctr %r12
|
|
lis %r12,0 # lis 12,obj@ha
|
|
addi %r12,%r12,0 # addi 12,12,obj@l
|
|
bctr
|
|
|
|
/*
|
|
* _rtld_powerpc_pltcall()
|
|
*
|
|
* This routine is copied into the 72-byte reserved area at the
|
|
* start of the PLT. The reloc.c:init_pltgot() routine inserts
|
|
* the absolute address of the jumptable.
|
|
* Control is transferred to this routine when the binder has
|
|
* located the external routine, but determined that it is > 32Mb
|
|
* from the PLT slot. Code is inserted into the PLT slot to set up
|
|
* %r11 with the jumptable index, and jump to here, where the
|
|
* absolute address of the external routine is loaded from the
|
|
* jumptable and transferred to
|
|
*/
|
|
_ENTRY(_rtld_powerpc_pltcall)
|
|
slwi %r11,%r11,2 # jmptab offset = index * 4
|
|
addis %r11,%r11,0 # addis 11,11,jmptab@ha
|
|
lwz %r11,0(%r11) # lwz 11,jmptab@l(11)
|
|
mtctr %r11
|
|
bctr # (*jmptab[index])()
|
|
|
|
|