bionic/linker/arch/x86/begin.c

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/*
* Copyright (C) 2012 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*/
extern unsigned __linker_init(unsigned int *elfdata);
__attribute__((visibility("hidden")))
void _start() {
void *elfdata;
void (*start)(void);
elfdata = __builtin_frame_address(0) + sizeof(void *);
start = (void(*)(void))__linker_init(elfdata);
/* linker init returns (%eax) the _entry address in the main image */
/* entry point expects sp to point to elfdata */
__asm__ (
"mov %0, %%esp\n\t"
"jmp *%1\n\t"
: : "r"(elfdata), "r"(start) :
);
/* Unreachable */
}
/* Since linker has its own version of crtbegin (this file) it should have */
/* own version of __stack_chk_fail_local for the case when it's built with */
/* stack protector feature */
#include "arch-x86/bionic/__stack_chk_fail_local.h"