mirror of
https://sourceware.org/git/glibc.git
synced 2025-10-30 10:45:40 +03:00
104 lines
3.5 KiB
ArmAsm
104 lines
3.5 KiB
ArmAsm
/* Machine-dependent ELF startup code. PowerPC version.
|
|
Copyright (C) 1995-2012 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <sysdep.h>
|
|
|
|
/* Initial entry point code for the dynamic linker.
|
|
The C function `_dl_start' is the real entry point;
|
|
its return value is the user program's entry point. */
|
|
ENTRY(_start)
|
|
/* We start with the following on the stack, from top:
|
|
argc (4 bytes);
|
|
arguments for program (terminated by NULL);
|
|
environment variables (terminated by NULL);
|
|
arguments for the program loader. */
|
|
|
|
/* Call _dl_start with one parameter pointing at argc */
|
|
mr r3,r1
|
|
/* (we have to frob the stack pointer a bit to allow room for
|
|
_dl_start to save the link register). */
|
|
li r4,0
|
|
addi r1,r1,-16
|
|
stw r4,0(r1)
|
|
bl _dl_start@local
|
|
|
|
/* FALLTHRU */
|
|
_dl_start_user:
|
|
/* Now, we do our main work of calling initialisation procedures.
|
|
The ELF ABI doesn't say anything about parameters for these,
|
|
so we just pass argc, argv, and the environment.
|
|
Changing these is strongly discouraged (not least because argc is
|
|
passed by value!). */
|
|
|
|
/* Put our GOT pointer in r31, */
|
|
SETUP_GOT_ACCESS(r31,got_label)
|
|
addis r31,r31,_GLOBAL_OFFSET_TABLE_-got_label@ha
|
|
addi r31,r31,_GLOBAL_OFFSET_TABLE_-got_label@l
|
|
/* the address of _start in r30, */
|
|
mr r30,r3
|
|
/* &_dl_argc in 29, &_dl_argv in 27, and _dl_loaded in 28. */
|
|
lwz r28,_rtld_local@got(r31)
|
|
lwz r29,_dl_argc@got(r31)
|
|
lwz r27,INTUSE(_dl_argv)@got(r31)
|
|
|
|
/* Call _dl_init (_dl_loaded, _dl_argc, _dl_argv, _dl_argv+_dl_argc+1). */
|
|
lwz r3,0(r28)
|
|
lwz r4,0(r29)
|
|
lwz r5,0(r27)
|
|
slwi r6,r4,2
|
|
add r6,r5,r6
|
|
addi r6,r6,4
|
|
bl _dl_init_internal@local
|
|
|
|
/* Now, to conform to the ELF ABI, we have to: */
|
|
/* Pass argc (actually _dl_argc) in r3; */
|
|
lwz r3,0(r29)
|
|
/* pass argv (actually _dl_argv) in r4; */
|
|
lwz r4,0(r27)
|
|
/* pass envp (actually _dl_argv+_dl_argc+1) in r5; */
|
|
slwi r5,r3,2
|
|
add r6,r4,r5
|
|
addi r5,r6,4
|
|
/* pass the auxilary vector in r6. This is passed to us just after _envp. */
|
|
2: lwzu r0,4(r6)
|
|
cmpwi r0,0
|
|
bne 2b
|
|
addi r6,r6,4
|
|
/* Pass a termination function pointer (in this case _dl_fini) in r7. */
|
|
lwz r7,_dl_fini@got(r31)
|
|
/* Now, call the start function in r30... */
|
|
mtctr r30
|
|
/* Pass the stack pointer in r1 (so far so good), pointing to a NULL value.
|
|
(This lets our startup code distinguish between a program linked statically,
|
|
which linux will call with argc on top of the stack which will hopefully
|
|
never be zero, and a dynamically linked program which will always have
|
|
a NULL on the top of the stack).
|
|
Take the opportunity to clear LR, so anyone who accidentally returns
|
|
from _start gets SEGV. Also clear the next few words of the stack. */
|
|
|
|
_dl_main_dispatch:
|
|
li r31,0
|
|
stw r31,0(r1)
|
|
mtlr r31
|
|
stw r31,4(r1)
|
|
stw r31,8(r1)
|
|
stw r31,12(r1)
|
|
/* Go do it! */
|
|
bctr
|
|
END(_start)
|