105 lines
2.8 KiB
ArmAsm
105 lines
2.8 KiB
ArmAsm
/*
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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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.code32
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.global _entry, _leave
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.text
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.align 4
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/*
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* Our entry point - assume that the CPU is in 32 bit protected mode and
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* all segments are in a flat model. That's our operating mode, so we won't
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* change anything.
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*/
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_entry:
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jmp _init
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.align 4
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#define MB_MAGIC 0x1BADB002
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#define MB_FLAGS 0x00010003
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mb_header:
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.long MB_MAGIC
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.long MB_FLAGS
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.long -(MB_MAGIC + MB_FLAGS)
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.long mb_header
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.long _start
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.long _edata
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.long _end
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.long _init
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/*
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* This function saves off the previous stack and switches us to our
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* own execution environment.
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*/
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_init:
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/* No interrupts, please. */
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cli
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/* There is a bunch of stuff missing here to take arguments on the stack
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* See http://www.coreboot.org/Payload_API and exec.S.
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*/
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/* Store current stack pointer. */
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movl %esp, %esi
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/* Store EAX and EBX */
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movl %eax,loader_eax
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movl %ebx,loader_ebx
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/* Clear the bss */
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cld
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movl $.bss, %edi
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movl $_end, %ecx
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subl %edi, %ecx
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xor %ax, %ax
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rep stosb
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/* Setup new stack. */
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movl $_stack, %ebx
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movl %ebx, %esp
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/* Save old stack pointer. */
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pushl %esi
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/* Let's rock. */
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call start_main
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/* %eax has the return value - pass it on unmolested */
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_leave:
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/* Get old stack pointer. */
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popl %ebx
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/* Restore old stack. */
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movl %ebx, %esp
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/* Return to the original context. */
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ret
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