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/*
* This file is part of the libpayload project.
*
* Copyright (C) 2008 Advanced Micro Devices, Inc.
*
* 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 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 AUTHOR 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.
*/
/* calling syntax: i386_do_exec(long addr, int argc, char **argv, int *ret) */
/* This implements the payload API detailed here:
* https://www.coreboot.org/Payload_API
*/
.align 4
.text
.global i386_do_exec
.type i386_do_exec,@function
i386_do_exec:
pushl %ebp
movl %esp, %ebp
/* Save the remaining callee preserved registers */
pushl %ebx
pushl %esi
pushl %edi
/* Push argc and argv on to the stack.
*
* We need to put a dummy value inbetween, as argc should be at offset
* 0x10, according to the payload API.
*/
pushl 12(%ebp)
pushl $0
pushl 16(%ebp)
/* Push a "magic" number on the stack - the other payload will use this
* as a clue that the argc and argv values on the stack are sane.
*/
pushl $0x12345678
/* Jump to the code */
call *8(%ebp)
/* %eax has the return value */
/* Skip over the argc/argv stuff still on the stack.
* Don't assume %ebp is sane, here. Restore it from the stack.
*/
addl $0x10, %esp
/* Restore the saved registers */
popl %edi
popl %esi
popl %ebx
popl %ebp
/* Get pointer to return value and save the return value in it. */
movl 16(%esp), %ecx
movl %eax, (%ecx)
ret
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