begin.c revision 42b2c6a5eed5e4ef35315b8cd32d1355f12a69b6 
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30
31extern unsigned __linker_init(void* raw_args);
32
33__LIBC_HIDDEN__ void _start() {
34  void (*start)(void);
35
36  void* raw_args = (void*) ((uintptr_t) __builtin_frame_address(0) + sizeof(void*));
37  start = (void(*)(void))__linker_init(raw_args);
38
39  /* linker init returns (%eax) the _entry address in the main image */
40  /* entry point expects sp to point to raw_args */
41
42  __asm__ (
43     "mov %0, %%esp\n\t"
44     "jmp *%1\n\t"
45     : : "r"(raw_args), "r"(start) :
46  );
47
48  /* Unreachable */
49}
50
51/* Since linker has its own version of crtbegin (this file) it should have */
52/* own version of __stack_chk_fail_local for the case when it's built with */
53/* stack protector feature */
54
55#include "arch-x86/bionic/__stack_chk_fail_local.h"
56