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/*
* Architecture specific code used by dl-startup.c
* Copyright (C) 2016 Waldemar Brodkorb <wbx@uclibc-ng.org>
* Copyright (C) 2018 Kalray Inc.
*
* Ported from GNU libc
* Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
*/
/* Copyright (C) 1995-2016 Free Software Foundation, Inc.
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 <features.h>
/* This is the first bit of code, ever, executed in user space of a dynamically
* linked ELF.
* The kernel jumps on this with the following stack layout:
* argc argument counter (integer)
* argv[0] program name (pointer)
* argv[1..argc-1] program args (pointers)
* NULL
* env[0...N] environment variables (pointers)
* NULL
* auxvt[0...N] Auxiliary Vector Table elements (mixed types)
*
* We should call _dl_start($sp) (the argument should point to the previously
* described memory layout).
*
* Next we should skip N arguments (N == _dl_skip_args).
* Those correspond to the arguments which are consumed by the dynamic loader
* if it is called directly as a program, which is possible when
* __LDSO_STANDALONE_SUPPORT__ is defined.
*
* We eventually end up calling the main executable's _start (from ctr1.S).
* The address of this _start is returned by _dl_start (in $r0).
*
* We should call this with one argument (in $r0): the address of _dl_fini()
*/
__asm__("\
.text \n\
.globl _start \n\
.type _start, %function \n\
_start: \n\
copyd $r0 = $sp \n\
copyd $r18 = $sp \n\
andd $sp = $sp, -32 \n\
call _dl_start \n\
;; \n\
.globl _dl_start_user \n\
.type _dl_start_user, %function \n\
_dl_start_user: \n\
pcrel $r1 = @gotaddr() \n\
copyd $r5 = $r0 \n\
copyd $sp = $r18 \n\
;; \n\
ld $r2 = @gotoff(_dl_skip_args)[$r1] \n\
addd $r0 = $r1, @gotoff(_dl_fini) \n\
;; \n\
lwz $r3 = 0[$sp] \n\
;; \n\
sbfw $r4 = $r2, $r3 \n\
addx8d $sp = $r2, $sp \n\
;; \n\
sd 0[$sp] = $r4 \n\
icall $r5 \n\
;; \n\
");
/* Get a pointer to the argv array. On many platforms this can be just
* the address of the first argument, on other platforms we need to
* do something a little more subtle here. */
#define GET_ARGV(ARGVP, ARGS) ARGVP = (((unsigned long*)ARGS)+1)
/* Handle relocation of the symbols in the dynamic loader. */
static __always_inline
void PERFORM_BOOTSTRAP_RELOC(ELF_RELOC *rpnt, ElfW(Addr) *reloc_addr,
ElfW(Addr) symbol_addr, ElfW(Addr) load_addr, ElfW(Sym) *sym)
{
switch (ELF_R_TYPE(rpnt->r_info)) {
case R_KVX_NONE:
break;
case R_KVX_JMP_SLOT:
*reloc_addr = symbol_addr + rpnt->r_addend;
break;
case R_KVX_RELATIVE:
*reloc_addr = load_addr + rpnt->r_addend;
break;
default:
_dl_exit(1);
}
}
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