arch/s390/kernel/head64.S

/*
 * arch/s390/kernel/head64.S
 *
 * Copyright (C) IBM Corp. 1999,2006
 *
 *   Author(s):	Hartmut Penner <hp@de.ibm.com>
 *		Martin Schwidefsky <schwidefsky@de.ibm.com>
 *		Rob van der Heij <rvdhei@iae.nl>
 *		Heiko Carstens <heiko.carstens@de.ibm.com>
 *
 */

#
# startup-code at 0x10000, running in absolute addressing mode
# this is called either by the ipl loader or directly by PSW restart
# or linload or SALIPL
#
	.org	0x10000
startup:basr	%r13,0			# get base
.LPG0:	l	%r13,0f-.LPG0(%r13)
	b	0(%r13)
0:	.long	startup_continue

#
# params at 10400 (setup.h)
#
	.org	PARMAREA
	.quad	0			# IPL_DEVICE
	.quad	0			# INITRD_START
	.quad	0			# INITRD_SIZE

	.org	COMMAND_LINE
	.byte	"root=/dev/ram0 ro"
	.byte	0

	.org	0x11000

startup_continue:
	basr	%r13,0			# get base
.LPG1:	sll	%r13,1			# remove high order bit
	srl	%r13,1
	lhi	%r1,1			# mode 1 = esame
	mvi	__LC_AR_MODE_ID,1	# set esame flag
	slr	%r0,%r0 		# set cpuid to zero
	sigp	%r1,%r0,0x12		# switch to esame mode
	sam64				# switch to 64 bit mode
	lctlg	%c0,%c15,.Lctl-.LPG1(%r13)	# load control registers
	lg	%r12,.Lparmaddr-.LPG1(%r13)	# pointer to parameter area
					# move IPL device to lowcore
	mvc	__LC_IPLDEV(4),IPL_DEVICE+4-PARMAREA(%r12)
#
# Setup stack
#
	larl	%r15,init_thread_union
	lg	%r14,__TI_task(%r15)	# cache current in lowcore
	stg	%r14,__LC_CURRENT
	aghi	%r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union + THREAD_SIZE
	stg	%r15,__LC_KERNEL_STACK	# set end of kernel stack
	aghi	%r15,-160
	xc	__SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15) # clear backchain

	brasl	%r14,ipl_save_parameters
#
# clear bss memory
#
	larl	%r2,__bss_start 	# start of bss segment
	larl	%r3,_end		# end of bss segment
	sgr	%r3,%r2 		# length of bss
	sgr	%r4,%r4 		#
	sgr	%r5,%r5 		# set src,length and pad to zero
	mvcle	%r2,%r4,0		# clear mem
	jo	.-4			# branch back, if not finish

	l	%r2,.Lrcp-.LPG1(%r13)	# Read SCP forced command word
.Lservicecall:
	stosm	.Lpmask-.LPG1(%r13),0x01	# authorize ext interrupts

	stctg	%r0,%r0,.Lcr-.LPG1(%r13)	# get cr0
	la	%r1,0x200		# set bit 22
	og	%r1,.Lcr-.LPG1(%r13)	# or old cr0 with r1
	stg	%r1,.Lcr-.LPG1(%r13)
	lctlg	%r0,%r0,.Lcr-.LPG1(%r13)	# load modified cr0

	mvc	__LC_EXT_NEW_PSW(8),.Lpcmsk-.LPG1(%r13) # set postcall psw
	larl	%r1,.Lsclph
	stg	%r1,__LC_EXT_NEW_PSW+8	# set handler

	larl	%r4,.Lsccb		# %r4 is our index for sccb stuff
	lgr	%r1,%r4			# our sccb
	.insn	rre,0xb2200000,%r2,%r1	# service call
	ipm	%r1
	srl	%r1,28			# get cc code
	xr	%r3,%r3
	chi	%r1,3
	be	.Lfchunk-.LPG1(%r13)	# leave
	chi	%r1,2
	be	.Lservicecall-.LPG1(%r13)
	lpswe	.Lwaitsclp-.LPG1(%r13)
.Lsclph:
	lh	%r1,.Lsccbr-.Lsccb(%r4)
	chi	%r1,0x10		# 0x0010 is the sucess code
	je	.Lprocsccb		# let's process the sccb
	chi	%r1,0x1f0
	bne	.Lfchunk-.LPG1(%r13)	# unhandled error code
	c	%r2,.Lrcp-.LPG1(%r13)	# Did we try Read SCP forced
	bne	.Lfchunk-.LPG1(%r13)	# if no, give up
	l	%r2,.Lrcp2-.LPG1(%r13)	# try with Read SCP
	b	.Lservicecall-.LPG1(%r13)
.Lprocsccb:
	lghi	%r1,0
	icm	%r1,3,.Lscpincr1-.Lsccb(%r4)	# use this one if != 0
	jnz	.Lscnd
	lg	%r1,.Lscpincr2-.Lsccb(%r4)	# otherwise use this one
.Lscnd:
	xr	%r3,%r3			# same logic
	ic	%r3,.Lscpa1-.Lsccb(%r4)
	chi	%r3,0x00
	jne	.Lcompmem
	l	%r3,.Lscpa2-.Lsccb(%r4)
.Lcompmem:
	mlgr	%r2,%r1			# mem in MB on 128-bit
	l	%r1,.Lonemb-.LPG1(%r13)
	mlgr	%r2,%r1			# mem size in bytes in %r3
	b	.Lfchunk-.LPG1(%r13)

	.align	4
.Lpmask:
	.byte	0
	.align	8
.Lcr:
	.quad	0x00  # place holder for cr0
.Lwaitsclp:
	.quad	0x0102000180000000,.Lsclph
.Lrcp:
	.int	0x00120001 # Read SCP forced code
.Lrcp2:
	.int	0x00020001 # Read SCP code
.Lonemb:
	.int	0x100000

.Lfchunk:
					# set program check new psw mask
	mvc	__LC_PGM_NEW_PSW(8),.Lpcmsk-.LPG1(%r13)

#
# find memory chunks.
#
	lgr	%r9,%r3			# end of mem
	larl	%r1,.Lchkmem		# set program check address
	stg	%r1,__LC_PGM_NEW_PSW+8
	la	%r1,1			# test in increments of 128KB
	sllg	%r1,%r1,17
	larl	%r3,memory_chunk
	slgr	%r4,%r4 		# set start of chunk to zero
	slgr	%r5,%r5 		# set end of chunk to zero
	slr	%r6,%r6			# set access code to zero
	la	%r10,MEMORY_CHUNKS	# number of chunks
.Lloop:
	tprot	0(%r5),0		# test protection of first byte
	ipm	%r7
	srl	%r7,28
	clr	%r6,%r7			# compare cc with last access code
	je	.Lsame
	j	.Lchkmem
.Lsame:
	algr	%r5,%r1			# add 128KB to end of chunk
					# no need to check here,
	brc	12,.Lloop		# this is the same chunk
.Lchkmem:				# > 16EB or tprot got a program check
	clgr	%r4,%r5			# chunk size > 0?
	je	.Lchkloop
	stg	%r4,0(%r3)		# store start address of chunk
	lgr	%r0,%r5
	slgr	%r0,%r4
	stg	%r0,8(%r3)		# store size of chunk
	st	%r6,20(%r3)		# store type of chunk
	la	%r3,24(%r3)
	larl	%r8,memory_size
	stg	%r5,0(%r8)		# store memory size
	ahi	%r10,-1			# update chunk number
.Lchkloop:
	lr	%r6,%r7			# set access code to last cc
	# we got an exception or we're starting a new
	# chunk , we must check if we should
	# still try to find valid memory (if we detected
	# the amount of available storage), and if we
	# have chunks left
	lghi	%r4,1
	sllg	%r4,%r4,31
	clgr	%r5,%r4
	je	.Lhsaskip
	xr	%r0, %r0
	clgr	%r0, %r9		# did we detect memory?
	je	.Ldonemem		# if not, leave
	chi	%r10, 0			# do we have chunks left?
	je	.Ldonemem
.Lhsaskip:
	algr	%r5,%r1			# add 128KB to end of chunk
	lgr	%r4,%r5			# potential new chunk
	clgr	%r5,%r9			# should we go on?
	jl	.Lloop
.Ldonemem:

	larl	%r12,machine_flags
#
# find out if we are running under VM
#
	stidp	__LC_CPUID		# store cpuid
	tm	__LC_CPUID,0xff 	# running under VM ?
	bno	0f-.LPG1(%r13)
	oi	7(%r12),1		# set VM flag
0:	lh	%r0,__LC_CPUID+4	# get cpu version
	chi	%r0,0x7490		# running on a P/390 ?
	bne	1f-.LPG1(%r13)
	oi	7(%r12),4		# set P/390 flag
1:

#
# find out if we have the MVPG instruction
#
	la	%r1,0f-.LPG1(%r13)	# set program check address
	stg	%r1,__LC_PGM_NEW_PSW+8
	sgr	%r0,%r0
	lghi	%r1,0
	lghi	%r2,0
	mvpg	%r1,%r2 		# test MVPG instruction
	oi	7(%r12),16		# set MVPG flag
0:

#
# find out if the diag 0x44 works in 64 bit mode
#
	la	%r1,0f-.LPG1(%r13)	# set program check address
	stg	%r1,__LC_PGM_NEW_PSW+8
	diag	0,0,0x44		# test diag 0x44
	oi	7(%r12),32		# set diag44 flag
0:

#
# find out if we have the IDTE instruction
#
	la	%r1,0f-.LPG1(%r13)	# set program check address
	stg	%r1,__LC_PGM_NEW_PSW+8
	.long	0xb2b10000		# store facility list
	tm	0xc8,0x08		# check bit for clearing-by-ASCE
	bno	0f-.LPG1(%r13)
	lhi	%r1,2094
	lhi	%r2,0
	.long	0xb98e2001
	oi	7(%r12),0x80		# set IDTE flag
0:

#
# find out if the diag 0x9c is available
#
	la     %r1,0f-.LPG1(%r13)	# set program check address
	stg    %r1,__LC_PGM_NEW_PSW+8
	stap   __LC_CPUID+4		# store cpu address
	lh     %r1,__LC_CPUID+4
	diag   %r1,0,0x9c		# test diag 0x9c
	oi     6(%r12),1		# set diag9c flag
0:

#
# find out if we have the MVCOS instruction
#
	la	%r1,0f-.LPG1(%r13)	# set program check address
	stg	%r1,__LC_PGM_NEW_PSW+8
	.short	0xc800			# mvcos 0(%r0),0(%r0),%r0
	.short	0x0000
	.short	0x0000
0:	tm	0x8f,0x13		# special-operation exception?
	bno	1f-.LPG1(%r13)		# if yes, MVCOS is present
	oi	6(%r12),2		# set MVCOS flag
1:

	lpswe	.Lentry-.LPG1(13)	# jump to _stext in primary-space,
					# virtual and never return ...
	.align	16
.Lentry:.quad	0x0000000180000000,_stext
.Lctl:	.quad	0x04b50002		# cr0: various things
	.quad	0			# cr1: primary space segment table
	.quad	.Lduct			# cr2: dispatchable unit control table
	.quad	0			# cr3: instruction authorization
	.quad	0			# cr4: instruction authorization
	.quad	0xffffffffffffffff	# cr5: primary-aste origin
	.quad	0			# cr6:	I/O interrupts
	.quad	0			# cr7:	secondary space segment table
	.quad	0			# cr8:	access registers translation
	.quad	0			# cr9:	tracing off
	.quad	0			# cr10: tracing off
	.quad	0			# cr11: tracing off
	.quad	0			# cr12: tracing off
	.quad	0			# cr13: home space segment table
	.quad	0xc0000000		# cr14: machine check handling off
	.quad	0			# cr15: linkage stack operations
.Lduct: .long	0,0,0,0,0,0,0,0
	.long	0,0,0,0,0,0,0,0
.Lpcmsk:.quad	0x0000000180000000
.L4malign:.quad 0xffffffffffc00000
.Lscan2g:.quad	0x80000000 + 0x20000 - 8	# 2GB + 128K - 8
.Lnop:	.long	0x07000700
.Lparmaddr:
	.quad	PARMAREA

	.globl	ipl_schib
ipl_schib:
	.rept 13
	.long 0
	.endr

	.globl	ipl_flags
ipl_flags:
	.long	0
	.globl	ipl_devno
ipl_devno:
	.word 0

	.org	0x12000
.globl s390_readinfo_sccb
s390_readinfo_sccb:
.Lsccb:
	.hword	0x1000			# length, one page
	.byte	0x00,0x00,0x00
	.byte	0x80			# variable response bit set
.Lsccbr:
	.hword	0x00			# response code
.Lscpincr1:
	.hword	0x00
.Lscpa1:
	.byte	0x00
	.fill	89,1,0
.Lscpa2:
	.int	0x00
.Lscpincr2:
	.quad	0x00
	.fill	3984,1,0
	.org	0x13000

#ifdef CONFIG_SHARED_KERNEL
	.org	0x100000
#endif

#
# startup-code, running in absolute addressing mode
#
	.globl	_stext
_stext:	basr	%r13,0			# get base
.LPG3:
# check control registers
	stctg	%c0,%c15,0(%r15)
	oi	6(%r15),0x40		# enable sigp emergency signal
	oi	4(%r15),0x10		# switch on low address proctection
	lctlg	%c0,%c15,0(%r15)

	lam	0,15,.Laregs-.LPG3(%r13)	# load acrs needed by uaccess
	brasl	%r14,start_kernel	# go to C code
#
# We returned from start_kernel ?!? PANIK
#
	basr	%r13,0
	lpswe	.Ldw-.(%r13)		# load disabled wait psw

	.align	8
.Ldw:	.quad	0x0002000180000000,0x0000000000000000
.Laregs:.long	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0