source: mainline/boot/arch/ppc64/loader/asm.S@ fb0e6f03

#
# Copyright (C) 2006 Martin Decky
# 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 "asm.h"
#include "regname.h"

.text

.global halt
.global memcpy
.global jump_to_kernel

halt:
        b halt

memcpy:
        srwi. r7, r5, 3
        addi r6, r3, -4
        addi r4, r4, -4
        beq     2f
        
        andi. r0, r6, 3
        mtctr r7
        bne 5f
        
        1:
        
        lwz r7, 4(r4)
        lwzu r8, 8(r4)
        stw r7, 4(r6)
        stwu r8, 8(r6)
        bdnz 1b
        
        andi. r5, r5, 7
        
        2:
        
        cmplwi 0, r5, 4
        blt 3f
        
        lwzu r0, 4(r4)
        addi r5, r5, -4
        stwu r0, 4(r6)
        
        3:
        
        cmpwi 0, r5, 0
        beqlr
        mtctr r5
        addi r4, r4, 3
        addi r6, r6, 3
        
        4:
        
        lbzu r0, 1(r4)
        stbu r0, 1(r6)
        bdnz 4b
        blr
        
        5:
        
        subfic r0, r0, 4
        mtctr r0
        
        6:
        
        lbz r7, 4(r4)
        addi r4, r4, 1
        stb r7, 4(r6)
        addi r6, r6, 1
        bdnz 6b
        subf r5, r0, r5
        rlwinm. r7, r5, 32-3, 3, 31
        beq 2b
        mtctr r7
        b 1b


jump_to_kernel:
        
        # r3 = bootinfo (pa)
        # r4 = bootinfo_size
        # r5 = trans (pa)
        # r6 = bytes to copy
        # r7 = real_mode (pa)
        
        # disable interrupts
        
        mfmsr r31
        rlwinm r31, r31, 0, 17, 15
        mtmsr r31
        
        # set real_mode meeting point address
        
        mtspr srr0, r7
        
        # jumps to real_mode
        
        mfmsr r31
        lis r30, ~0@h
        ori r30, r30, ~(msr_ir | msr_dr)@l
        and r31, r31, r30
        mtspr srr1, r31
        
        sync
        isync
        rfid

.section REALMODE, "ax"
.align PAGE_WIDTH
.global real_mode

real_mode:
        
        # copy kernel to proper location
        #
        # r5 = trans (pa)
        # r6 = bytes to copy
        
        li r31, PAGE_SIZE >> 2
        li r30, 0
        
        page_copy:
                
                cmpwi r6, 0
                beq copy_end
                
                # copy page
                
                mtctr r31
                lwz r29, 0(r5)
                
                copy_loop:
                        
                        lwz r28, 0(r29)
                        stw r28, 0(r30)
                        
                        addi r29, r29, 4
                        addi r30, r30, 4
                        subi r6, r6, 4
                        
                        cmpwi r6, 0
                        beq copy_end
                        
                        bdnz copy_loop
                
                addi r5, r5, 4
                b page_copy
        
        copy_end:
        
        # initially fill segment registers

        li r31, 16
        mtctr r31
        li r31, 0
        li r30, 0x2000

        seg_fill:
        
                mtsrin r30, r31
                addi r30, r30, 0x111
                addis r31, r31, 0x1000    # move to next SR
                
                bdnz seg_fill
        
        tlbia
        tlbsync
        
        # start the kernel
        #
        # r3 = bootinfo (pa)
        
        lis r31, KERNEL_START_ADDR@ha
        addi r31, r31, KERNEL_START_ADDR@l
        
        mtspr srr0, r31
        
        mfmsr r31
        ori r31, r31, (msr_ir | msr_dr)@l
        mtspr srr1, r31
        
        sync
        isync
        rfid

.align PAGE_WIDTH
.global trans
trans:
        .space (TRANS_SIZE * TRANS_ITEM_SIZE)