libpayload: Add an exec() and i386_do_exec() function
Add functions for libpayload to execute other payloads in memory, and have those functions return cleanly. Signed-off-by: Jordan Crouse <jordan.crouse@amd.com> Acked-by: Uwe Hermann <uwe@hermann-uwe.de> git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3338 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
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payloads/libpayload/i386/exec.S
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99
payloads/libpayload/i386/exec.S
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/*
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* This file is part of the libpayload project.
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*
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* Copyright (C) 2008 Advanced Micro Devices, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/* calling syntax: i386_do_exec(long addr, int argc, char **argv, int *ret) */
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/* This implements the payload API detailed here:
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* http://www.coreboot.org/Payload_API
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*/
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.align 4
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.text
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.global i386_do_exec
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.type i386_do_exec,@function
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i386_do_exec:
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pushl %ebp
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movl %esp, %ebp
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pushl %eax
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/* Put the run address in %eax */
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movl 8(%ebp), %eax
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/* Save off the rest of the registers */
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pushl %esi
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pushl %ecx
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pushl %ebp
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/* Push the argc and argv pointers on to the stack */
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movl 12(%ebp), %esi
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movl 16(%ebp), %ecx
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pushl %esi
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pushl %ecx
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/* Move a "magic" number on the stack - the other
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* payload will use this as a clue that the argc
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* and argv are sane
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*/
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movl $12345678, %ecx
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pushl %ecx
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/* Jump to the code */
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call *%eax
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/* %eax has the return value */
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/* Skip over the argc/argv stuff still on the stack */
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addl $12, %esp
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/* Get back %ebp */
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popl %ebp
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/* Get the pointer to the return value
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* and save the return value in it
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*/
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movl 20(%ebp), %ecx
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movl %eax, (%eax)
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/* Get the rest of the saved registers */
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popl %ecx
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popl %esi
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popl %eax
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/* Restore the stack pointer */
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movl %ebp,%esp
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popl %ebp
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ret
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