Subversion Repositories HelenOS-historic

#

# Copyright (C) 2005 Jakub Jermar

# 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.

# - 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 ``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 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.

#

#include <arch/asm/regname.h>

#include <arch/asm/spr.h>

.section K_TEXT_START

.global kernel_image_start

.org 0x0

/* 256 bytes of some data */

/* exception table - must use 'ba' instructions for branches,

 * because it is elsewhere than the linker thinks

 */

.space 4096

kernel_image_start:

	/* Initialize OFW, might be needed before relocate_kernel? */

	lis r4, ofw@ha

	addi r4, r4, ofw@l

	stw r5, 0(r4)

	bl ofw_init

	bl preboot_read_config

	bl relocate_kernel

__after_reloc:

	/* Set stack to some more meaningful value */

	/* TODO: This is hardcoded for PearPC, must be changed later */

	lis r1, 0x70

	b main_bsp

relocate_kernel:

	/* TODO: We _know_ that pearpc loads it to 8MB, and

	 * but it should be really generic

	 */

	lis r4, 0x80 /* r4 is where data was loaded - 8MB */

	bl to_real_mode

	/* Now we are in real mode, copy first block and jump to it,

	 * we are running in the loaded kernel now

	 * We still have in r3 physical load kernel address

	 */

	b __after_reloc /* We know in pearpc we are ok, so return,

	                 * otherwise we should relocate kernel

		         * here

	                 */

/* Turn off page translation

 * - assume that physical-loaded address is in r4

 */

to_real_mode:

	mflr r0

	lis   r5, ktext_start@ha // Expected start of kernel

	addi r5, r5, ktext_start@l

	add  r0, r4, r0  	

	sub  r0, r0, r5         // r0 now contains physical return address

	mfmsr r3

	andis. r3, r3, (~MSR_DR | MSR_IR) >> 16

	mtspr SPRN_SRR0, r0

	mtspr SPRN_SRR1, r3

	sync 			// Really needed? RFI should do it as well?

	RFI