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#
# kexec: Linux boots Linux
#
# Copyright (C) 2004 - 2005, Milton D Miller II, IBM Corporation
# Copyright (C) 2006, Mohan Kumar M (mohan@in.ibm.com), IBM Corporation
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation (version 2 of the License).
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
# v2wrap.S
# a wrapper to call purgatory code to backup first
# 32kB of first kernel into the backup region
# reserved by kexec-tools.
# Invokes powerpc kernel with the expected arguments
# of kernel(device-tree, phys-offset, 0)
#
# calling convention:
# r3 = physical number of this cpu (all cpus)
# r4 = address of this chunk (master only)
# master enters at purgatory_start (aka first byte of this chunk)
# slaves (additional cpus), if any, enter a copy of the
# first 0x100 bytes of this code relocated to 0x0
#
# in other words,
# a copy of the first 0x100 bytes of this code is copied to 0
# and the slaves are sent to address 0x60
# with r3 = their physical cpu number.
.globl purgatory_start
purgatory_start: b master
.org purgatory_start + 0x60 # ABI: slaves start at 60 with r3=phys
slave: b $
.org purgatory_start + 0x100 # ABI: end of copied region
.size purgatory_start, . - purgatory_start
#
# The above 0x100 bytes at purgatory_start are replaced with the
# code from the kernel (or next stage) by kexec/arch/powerpc/kexec-powerpc.c
#
master:
or 1,1,1 # low priority to let other threads catchup
isync
mr 17,3 # save cpu id to r17
mr 15,4 # save physical address in reg15
lis 6,my_thread_ptr@h
ori 6,6,my_thread_ptr@l
lwz 2,0(6) # setup ThreadPointer(TP)
lis 6,stack@h
ori 6,6,stack@l
lwz 1,0(6) #setup stack
subi 1,1,112
bl purgatory
nop
or 3,3,3 # ok now to high priority, lets boot
lis 6,0x1
mtctr 6 # delay a bit for slaves to catch up
83: bdnz 83b # before we overwrite 0-100 again
lis 6,dt_offset@h
ori 6,6,dt_offset@l
lwz 3,0(6) # load device-tree address
lwz 6,20(3) # fetch version number
cmpwi 0,6,2 # v2 ?
blt 80f
stw 17,28(3) # save my cpu number as boot_cpu_phys
80:
lis 6,kernel@h
ori 6,6,kernel@l
lwz 4,0(6) # load the kernel address
li 5,0 # r5 will be 0 for kernel
li 6,0 # clear r6 for good measure
mtctr 4 # prepare branch too
lwz 8,0(4) # get the first instruction that we stole
stw 8,0(0) # and put it in the slave loop at 0
# skip cache flush, do we care?
bctr # start kernel
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