head.S

/*
 * Copyright IBM Corp. 1999, 2010
 *
 *    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>
 *
 * There are 5 different IPL methods
 *  1) load the image directly into ram at address 0 and do an PSW restart
 *  2) linload will load the image from address 0x10000 to memory 0x10000
 *     and start the code thru LPSW 0x0008000080010000 (VM only, deprecated)
 *  3) generate the tape ipl header, store the generated image on a tape
 *     and ipl from it
 *     In case of SL tape you need to IPL 5 times to get past VOL1 etc
 *  4) generate the vm reader ipl header, move the generated image to the
 *     VM reader (use option NOH!) and do a ipl from reader (VM only)
 *  5) direct call of start by the SALIPL loader
 *  We use the cpuid to distinguish between VM and native ipl
 *  params for kernel are pushed to 0x10400 (see setup.h)
 *
 */

#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/page.h>

#ifdef CONFIG_64BIT
#define ARCH_OFFSET	4
#else
#define ARCH_OFFSET	0
#endif

__HEAD

#define IPL_BS	0x730
	.org	0
	.long	0x00080000,0x80000000+iplstart	# The first 24 bytes are loaded
	.long	0x02000018,0x60000050		# by ipl to addresses 0-23.
	.long	0x02000068,0x60000050		# (a PSW and two CCWs).
	.fill	80-24,1,0x40			# bytes 24-79 are discarded !!
	.long	0x020000f0,0x60000050		# The next 160 byte are loaded
	.long	0x02000140,0x60000050		# to addresses 0x18-0xb7
	.long	0x02000190,0x60000050		# They form the continuation
	.long	0x020001e0,0x60000050		# of the CCW program started
	.long	0x02000230,0x60000050		# by ipl and load the range
	.long	0x02000280,0x60000050		# 0x0f0-0x730 from the image
	.long	0x020002d0,0x60000050		# to the range 0x0f0-0x730
	.long	0x02000320,0x60000050		# in memory. At the end of
	.long	0x02000370,0x60000050		# the channel program the PSW
	.long	0x020003c0,0x60000050		# at location 0 is loaded.
	.long	0x02000410,0x60000050		# Initial processing starts
	.long	0x02000460,0x60000050		# at 0x200 = iplstart.
	.long	0x020004b0,0x60000050
	.long	0x02000500,0x60000050
	.long	0x02000550,0x60000050
	.long	0x020005a0,0x60000050
	.long	0x020005f0,0x60000050
	.long	0x02000640,0x60000050
	.long	0x02000690,0x60000050
	.long	0x020006e0,0x20000050

	.org	0x200
#
# subroutine to set architecture mode
#
.Lsetmode:
#ifdef CONFIG_64BIT
	mvi	__LC_AR_MODE_ID,1	# set esame flag
	slr	%r0,%r0 		# set cpuid to zero
	lhi	%r1,2			# mode 2 = esame (dump)
	sigp	%r1,%r0,0x12		# switch to esame mode
	bras	%r13,0f
	.fill	16,4,0x0
0:	lmh	%r0,%r15,0(%r13)	# clear high-order half of gprs
	sam31				# switch to 31 bit addressing mode
#else
	mvi	__LC_AR_MODE_ID,0	# set ESA flag (mode 0)
#endif
	br	%r14

#
# subroutine to wait for end I/O
#
.Lirqwait:
#ifdef CONFIG_64BIT
	mvc	0x1f0(16),.Lnewpsw	# set up IO interrupt psw
	lpsw	.Lwaitpsw
.Lioint:
	br	%r14
	.align	8
.Lnewpsw:
	.quad	0x0000000080000000,.Lioint
#else
	mvc	0x78(8),.Lnewpsw	# set up IO interrupt psw
	lpsw	.Lwaitpsw
.Lioint:
	br	%r14
	.align	8
.Lnewpsw:
	.long	0x00080000,0x80000000+.Lioint
#endif
.Lwaitpsw:
	.long	0x020a0000,0x80000000+.Lioint

#
# subroutine for loading cards from the reader
#
.Lloader:
	la	%r4,0(%r14)
	la	%r3,.Lorb		# r2 = address of orb into r2
	la	%r5,.Lirb		# r4 = address of irb
	la	%r6,.Lccws
	la	%r7,20
.Linit:
	st	%r2,4(%r6)		# initialize CCW data addresses
	la	%r2,0x50(%r2)
	la	%r6,8(%r6)
	bct	7,.Linit

	lctl	%c6,%c6,.Lcr6		# set IO subclass mask
	slr	%r2,%r2
.Lldlp:
	ssch	0(%r3)			# load chunk of 1600 bytes
	bnz	.Llderr
.Lwait4irq:
	bas	%r14,.Lirqwait
	c	%r1,0xb8		# compare subchannel number
	bne	.Lwait4irq
	tsch	0(%r5)

	slr	%r0,%r0
	ic	%r0,8(%r5)		# get device status
	chi	%r0,8			# channel end ?
	be	.Lcont
	chi	%r0,12			# channel end + device end ?
	be	.Lcont

	l	%r0,4(%r5)
	s	%r0,8(%r3)		# r0/8 = number of ccws executed
	mhi	%r0,10			# *10 = number of bytes in ccws
	lh	%r3,10(%r5)		# get residual count
	sr	%r0,%r3 		# #ccws*80-residual=#bytes read
	ar	%r2,%r0

	br	%r4			# r2 contains the total size

.Lcont:
	ahi	%r2,0x640		# add 0x640 to total size
	la	%r6,.Lccws
	la	%r7,20
.Lincr:
	l	%r0,4(%r6)		# update CCW data addresses
	ahi	%r0,0x640
	st	%r0,4(%r6)
	ahi	%r6,8
	bct	7,.Lincr

	b	.Lldlp
.Llderr:
	lpsw	.Lcrash

	.align	8
.Lorb:	.long	0x00000000,0x0080ff00,.Lccws
.Lirb:	.long	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.Lcr6:	.long	0xff000000
.Lloadp:.long	0,0
	.align	8
.Lcrash:.long	0x000a0000,0x00000000

	.align	8
.Lccws: .rept	19
	.long	0x02600050,0x00000000
	.endr
	.long	0x02200050,0x00000000

iplstart:
	bas	%r14,.Lsetmode		# Immediately switch to 64 bit mode
	lh	%r1,0xb8		# test if subchannel number
	bct	%r1,.Lnoload		#  is valid
	l	%r1,0xb8		# load ipl subchannel number
	la	%r2,IPL_BS		# load start address
	bas	%r14,.Lloader		# load rest of ipl image
	l	%r12,.Lparm		# pointer to parameter area
	st	%r1,IPL_DEVICE+ARCH_OFFSET-PARMAREA(%r12) # save ipl device number

#
# load parameter file from ipl device
#
.Lagain1:
	l	%r2,.Linitrd		# ramdisk loc. is temp
	bas	%r14,.Lloader		# load parameter file
	ltr	%r2,%r2 		# got anything ?
	bz	.Lnopf
	chi	%r2,895
	bnh	.Lnotrunc
	la	%r2,895
.Lnotrunc:
	l	%r4,.Linitrd
	clc	0(3,%r4),.L_hdr		# if it is HDRx
	bz	.Lagain1		# skip dataset header
	clc	0(3,%r4),.L_eof		# if it is EOFx
	bz	.Lagain1		# skip dateset trailer
	la	%r5,0(%r4,%r2)
	lr	%r3,%r2
	la	%r3,COMMAND_LINE-PARMAREA(%r12) # load adr. of command line
	mvc	0(256,%r3),0(%r4)
	mvc	256(256,%r3),256(%r4)
	mvc	512(256,%r3),512(%r4)
	mvc	768(122,%r3),768(%r4)
	slr	%r0,%r0
	b	.Lcntlp
.Ldelspc:
	ic	%r0,0(%r2,%r3)
	chi	%r0,0x20		# is it a space ?
	be	.Lcntlp
	ahi	%r2,1
	b	.Leolp
.Lcntlp:
	brct	%r2,.Ldelspc
.Leolp:
	slr	%r0,%r0
	stc	%r0,0(%r2,%r3)		# terminate buffer
.Lnopf:

#
# load ramdisk from ipl device
#
.Lagain2:
	l	%r2,.Linitrd		# addr of ramdisk
	st	%r2,INITRD_START+ARCH_OFFSET-PARMAREA(%r12)
	bas	%r14,.Lloader		# load ramdisk
	st	%r2,INITRD_SIZE+ARCH_OFFSET-PARMAREA(%r12) # store size of rd
	ltr	%r2,%r2
	bnz	.Lrdcont
	st	%r2,INITRD_START+ARCH_OFFSET-PARMAREA(%r12) # no ramdisk found
.Lrdcont:
	l	%r2,.Linitrd

	clc	0(3,%r2),.L_hdr		# skip HDRx and EOFx
	bz	.Lagain2
	clc	0(3,%r2),.L_eof
	bz	.Lagain2

#
# reset files in VM reader
#
	stidp	.Lcpuid			# store cpuid
	tm	.Lcpuid,0xff		# running VM ?
	bno	.Lnoreset
	la	%r2,.Lreset
	lhi	%r3,26
	diag	%r2,%r3,8
	la	%r5,.Lirb
	stsch	0(%r5)			# check if irq is pending
	tm	30(%r5),0x0f		# by verifying if any of the
	bnz	.Lwaitforirq		# activity or status control
	tm	31(%r5),0xff		# bits is set in the schib
	bz	.Lnoreset
.Lwaitforirq:
	bas	%r14,.Lirqwait		# wait for IO interrupt
	c	%r1,0xb8		# compare subchannel number
	bne	.Lwaitforirq
	la	%r5,.Lirb
	tsch	0(%r5)
.Lnoreset:
	b	.Lnoload

#
# everything loaded, go for it
#
.Lnoload:
	l	%r1,.Lstartup
	br	%r1

.Linitrd:.long _end			# default address of initrd
.Lparm:	.long  PARMAREA
.Lstartup: .long startup
.Lreset:.byte	0xc3,0xc8,0xc1,0xd5,0xc7,0xc5,0x40,0xd9,0xc4,0xd9,0x40
	.byte	0xc1,0xd3,0xd3,0x40,0xd2,0xc5,0xc5,0xd7,0x40,0xd5,0xd6
	.byte	0xc8,0xd6,0xd3,0xc4	# "change rdr all keep nohold"
.L_eof: .long	0xc5d6c600	 /* C'EOF' */
.L_hdr: .long	0xc8c4d900	 /* C'HDR' */
	.align	8
.Lcpuid:.fill	8,1,0

#
# SALIPL loader support. Based on a patch by Rob van der Heij.
# This entry point is called directly from the SALIPL loader and
# doesn't need a builtin ipl record.
#
	.org	0x800
ENTRY(start)
	stm	%r0,%r15,0x07b0		# store registers
	bas	%r14,.Lsetmode		# Immediately switch to 64 bit mode
	basr	%r12,%r0
.base:
	l	%r11,.parm
	l	%r8,.cmd		# pointer to command buffer

	ltr	%r9,%r9			# do we have SALIPL parameters?
	bp	.sk8x8

	mvc	0(64,%r8),0x00b0	# copy saved registers
	xc	64(240-64,%r8),0(%r8)	# remainder of buffer
	tr	0(64,%r8),.lowcase
	b	.gotr
.sk8x8:
	mvc	0(240,%r8),0(%r9)	# copy iplparms into buffer
.gotr:
	slr	%r0,%r0
	st	%r0,INITRD_SIZE+ARCH_OFFSET-PARMAREA(%r11)
	st	%r0,INITRD_START+ARCH_OFFSET-PARMAREA(%r11)
	j	startup 		# continue with startup
.cmd:	.long	COMMAND_LINE		# address of command line buffer
.parm:	.long	PARMAREA
.lowcase:
	.byte 0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07
	.byte 0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f
	.byte 0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17
	.byte 0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f
	.byte 0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27
	.byte 0x28,0x29,0x2a,0x2b,0x2c,0x2d,0x2e,0x2f
	.byte 0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37
	.byte 0x38,0x39,0x3a,0x3b,0x3c,0x3d,0x3e,0x3f
	.byte 0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47
	.byte 0x48,0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f
	.byte 0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57
	.byte 0x58,0x59,0x5a,0x5b,0x5c,0x5d,0x5e,0x5f
	.byte 0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67
	.byte 0x68,0x69,0x6a,0x6b,0x6c,0x6d,0x6e,0x6f
	.byte 0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77
	.byte 0x78,0x79,0x7a,0x7b,0x7c,0x7d,0x7e,0x7f

	.byte 0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87
	.byte 0x88,0x89,0x8a,0x8b,0x8c,0x8d,0x8e,0x8f
	.byte 0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97
	.byte 0x98,0x99,0x9a,0x9b,0x9c,0x9d,0x9e,0x9f
	.byte 0xa0,0xa1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7
	.byte 0xa8,0xa9,0xaa,0xab,0xac,0xad,0xae,0xaf
	.byte 0xb0,0xb1,0xb2,0xb3,0xb4,0xb5,0xb6,0xb7
	.byte 0xb8,0xb9,0xba,0xbb,0xbc,0xbd,0xbe,0xbf
	.byte 0xc0,0x81,0x82,0x83,0x84,0x85,0x86,0x87	# .abcdefg
	.byte 0x88,0x89,0xca,0xcb,0xcc,0xcd,0xce,0xcf	# hi
	.byte 0xd0,0x91,0x92,0x93,0x94,0x95,0x96,0x97	# .jklmnop
	.byte 0x98,0x99,0xda,0xdb,0xdc,0xdd,0xde,0xdf	# qr
	.byte 0xe0,0xe1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7	# ..stuvwx
	.byte 0xa8,0xa9,0xea,0xeb,0xec,0xed,0xee,0xef	# yz
	.byte 0xf0,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7
	.byte 0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfe,0xff

#
# 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
ENTRY(startup)
	j	.Lep_startup_normal
	.org	0x10008
#
# This is a list of s390 kernel entry points. At address 0x1000f the number of
# valid entry points is stored.
#
# IMPORTANT: Do not change this table, it is s390 kernel ABI!
#
	.ascii	"S390EP"
	.byte	0x00,0x01
#
# kdump startup-code at 0x10010, running in 64 bit absolute addressing mode
#
	.org	0x10010
ENTRY(startup_kdump)
	j	.Lep_startup_kdump
.Lep_startup_normal:
#ifdef CONFIG_64BIT
	mvi	__LC_AR_MODE_ID,1	# set esame flag
	slr	%r0,%r0 		# set cpuid to zero
	lhi	%r1,2			# mode 2 = esame (dump)
	sigp	%r1,%r0,0x12		# switch to esame mode
	bras	%r13,0f
	.fill	16,4,0x0
0:	lmh	%r0,%r15,0(%r13)	# clear high-order half of gprs
	sam31				# switch to 31 bit addressing mode
#else
	mvi	__LC_AR_MODE_ID,0	# set ESA flag (mode 0)
#endif
	basr	%r13,0			# get base
.LPG0:
	xc	0x200(256),0x200	# partially clear lowcore
	xc	0x300(256),0x300
	xc	0xe00(256),0xe00
	stck	__LC_LAST_UPDATE_CLOCK
	spt	5f-.LPG0(%r13)
	mvc	__LC_LAST_UPDATE_TIMER(8),5f-.LPG0(%r13)
	xc	__LC_STFL_FAC_LIST(8),__LC_STFL_FAC_LIST
#ifndef CONFIG_MARCH_G5
	# check capabilities against MARCH_{G5,Z900,Z990,Z9_109,Z10}
	.insn	s,0xb2b10000,__LC_STFL_FAC_LIST	# store facility list
	tm	__LC_STFL_FAC_LIST,0x01	# stfle available ?
	jz	0f
	la	%r0,0
	.insn	s,0xb2b00000,__LC_STFL_FAC_LIST	# store facility list extended
0:	l	%r0,__LC_STFL_FAC_LIST
	n	%r0,2f+8-.LPG0(%r13)
	cl	%r0,2f+8-.LPG0(%r13)
	jne	1f
	l	%r0,__LC_STFL_FAC_LIST+4
	n	%r0,2f+12-.LPG0(%r13)
	cl	%r0,2f+12-.LPG0(%r13)
	je	3f
1:	l	%r15,.Lstack-.LPG0(%r13)
	ahi	%r15,-96
	la	%r2,.Lals_string-.LPG0(%r13)
	l	%r3,.Lsclp_print-.LPG0(%r13)
	basr	%r14,%r3
	lpsw	2f-.LPG0(%r13)		# machine type not good enough, crash
.Lals_string:
	.asciz	"The Linux kernel requires more recent processor hardware"
.Lsclp_print:
	.long	_sclp_print_early
.Lstack:
	.long	0x8000 + (1<<(PAGE_SHIFT+THREAD_ORDER))
	.align 16
2:	.long	0x000a0000,0x8badcccc
#if defined(CONFIG_64BIT)
#if defined(CONFIG_MARCH_Z196)
	.long 0xc100efe3, 0xf46c0000
#elif defined(CONFIG_MARCH_Z10)
	.long 0xc100efe3, 0xf0680000
#elif defined(CONFIG_MARCH_Z9_109)
	.long 0xc100efc3, 0x00000000
#elif defined(CONFIG_MARCH_Z990)
	.long 0xc0002000, 0x00000000
#elif defined(CONFIG_MARCH_Z900)
	.long 0xc0000000, 0x00000000
#endif
#else
#if defined(CONFIG_MARCH_Z196)
	.long 0x8100c880, 0x00000000
#elif defined(CONFIG_MARCH_Z10)
	.long 0x8100c880, 0x00000000
#elif defined(CONFIG_MARCH_Z9_109)
	.long 0x8100c880, 0x00000000
#elif defined(CONFIG_MARCH_Z990)
	.long 0x80002000, 0x00000000
#elif defined(CONFIG_MARCH_Z900)
	.long 0x80000000, 0x00000000
#endif
#endif
3:
#endif

#ifdef CONFIG_64BIT
	/* Continue with 64bit startup code in head64.S */
	sam64				# switch to 64 bit mode
	jg	startup_continue
#else
	/* Continue with 31bit startup code in head31.S */
	l	%r13,4f-.LPG0(%r13)
	b	0(%r13)
	.align	8
4:	.long	startup_continue
#endif

	.align	8
5:	.long	0x7fffffff,0xffffffff

#include "head_kdump.S"

#
# params at 10400 (setup.h)
#
	.org	PARMAREA
	.long	0,0			# IPL_DEVICE
	.long	0,0			# INITRD_START
	.long	0,0			# INITRD_SIZE
	.long	0,0			# OLDMEM_BASE
	.long	0,0			# OLDMEM_SIZE

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

	.org	0x11000