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