xref: /openbmc/linux/arch/s390/boot/head.S (revision 801b27e8) 
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright IBM Corp. 1999, 2010
4 *
5 *    Author(s): Hartmut Penner <hp@de.ibm.com>
6 *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
7 *		 Rob van der Heij <rvdhei@iae.nl>
8 *
9 * There are 5 different IPL methods
10 *  1) load the image directly into ram at address 0 and do an PSW restart
11 *  2) linload will load the image from address 0x10000 to memory 0x10000
12 *     and start the code thru LPSW 0x0008000080010000 (VM only, deprecated)
13 *  3) generate the tape ipl header, store the generated image on a tape
14 *     and ipl from it
15 *     In case of SL tape you need to IPL 5 times to get past VOL1 etc
16 *  4) generate the vm reader ipl header, move the generated image to the
17 *     VM reader (use option NOH!) and do a ipl from reader (VM only)
18 *  5) direct call of start by the SALIPL loader
19 *  We use the cpuid to distinguish between VM and native ipl
20 *  params for kernel are pushed to 0x10400 (see setup.h)
21 *
22 */
23
24#include <linux/init.h>
25#include <linux/linkage.h>
26#include <asm/asm-offsets.h>
27#include <asm/page.h>
28#include <asm/ptrace.h>
29#include <asm/sclp.h>
30#include "boot.h"
31
32#define EP_OFFSET	0x10008
33#define EP_STRING	"S390EP"
34#define IPL_BS		0x730
35
36__HEAD
37ipl_start:
38	mvi	__LC_AR_MODE_ID,1	# set esame flag
39	slr	%r0,%r0			# set cpuid to zero
40	lhi	%r1,2			# mode 2 = esame (dump)
41	sigp	%r1,%r0,0x12		# switch to esame mode
42	sam64				# switch to 64 bit addressing mode
43	lgh	%r1,__LC_SUBCHANNEL_ID	# test if subchannel number
44	brctg	%r1,.Lnoload		#  is valid
45	llgf	%r1,__LC_SUBCHANNEL_ID	# load ipl subchannel number
46	lghi	%r2,IPL_BS		# load start address
47	bras	%r14,.Lloader		# load rest of ipl image
48	larl	%r12,parmarea		# pointer to parameter area
49	stg	%r1,IPL_DEVICE-PARMAREA(%r12) # save ipl device number
50#
51# load parameter file from ipl device
52#
53.Lagain1:
54	larl	%r2,_end		# ramdisk loc. is temp
55	bras	%r14,.Lloader		# load parameter file
56	ltgr	%r2,%r2			# got anything ?
57	jz	.Lnopf
58	lg	%r3,MAX_COMMAND_LINE_SIZE-PARMAREA(%r12)
59	aghi	%r3,-1
60	clgr	%r2,%r3
61	jl	.Lnotrunc
62	lgr	%r2,%r3
63.Lnotrunc:
64	larl	%r4,_end
65	larl	%r13,.L_hdr
66	clc	0(3,%r4),0(%r13)	# if it is HDRx
67	jz	.Lagain1		# skip dataset header
68	larl	%r13,.L_eof
69	clc	0(3,%r4),0(%r13)	# if it is EOFx
70	jz	.Lagain1		# skip data set trailer
71	lgr	%r5,%r2
72	la	%r6,COMMAND_LINE-PARMAREA(%r12)
73	lgr	%r7,%r2
74	aghi	%r7,1
75	mvcl	%r6,%r4
76.Lnopf:
77#
78# load ramdisk from ipl device
79#
80.Lagain2:
81	larl	%r2,_end		# addr of ramdisk
82	stg	%r2,INITRD_START-PARMAREA(%r12)
83	bras	%r14,.Lloader		# load ramdisk
84	stg	%r2,INITRD_SIZE-PARMAREA(%r12) # store size of rd
85	ltgr	%r2,%r2
86	jnz	.Lrdcont
87	stg	%r2,INITRD_START-PARMAREA(%r12) # no ramdisk found
88.Lrdcont:
89	larl	%r2,_end
90	larl	%r13,.L_hdr		# skip HDRx and EOFx
91	clc	0(3,%r2),0(%r13)
92	jz	.Lagain2
93	larl	%r13,.L_eof
94	clc	0(3,%r2),0(%r13)
95	jz	.Lagain2
96#
97# reset files in VM reader
98#
99	larl	%r13,.Lcpuid
100	stidp	0(%r13)			# store cpuid
101	tm	0(%r13),0xff		# running VM ?
102	jno	.Lnoreset
103	larl	%r2,.Lreset
104	lghi	%r3,26
105	diag	%r2,%r3,8
106	larl	%r5,.Lirb
107	stsch	0(%r5)			# check if irq is pending
108	tm	30(%r5),0x0f		# by verifying if any of the
109	jnz	.Lwaitforirq		# activity or status control
110	tm	31(%r5),0xff		# bits is set in the schib
111	jz	.Lnoreset
112.Lwaitforirq:
113	bras	%r14,.Lirqwait		# wait for IO interrupt
114	c	%r1,__LC_SUBCHANNEL_ID	# compare subchannel number
115	jne	.Lwaitforirq
116	larl	%r5,.Lirb
117	tsch	0(%r5)
118.Lnoreset:
119	j	.Lnoload
120#
121# everything loaded, go for it
122#
123.Lnoload:
124	jg	startup
125#
126# subroutine to wait for end I/O
127#
128.Lirqwait:
129	larl	%r13,.Lnewpswmask	# set up IO interrupt psw
130	mvc	__LC_IO_NEW_PSW(8),0(%r13)
131	stg	%r14,__LC_IO_NEW_PSW+8
132	larl	%r13,.Lwaitpsw
133	lpswe	0(%r13)
134.Lioint:
135#
136# subroutine for loading cards from the reader
137#
138.Lloader:
139	lgr	%r4,%r14
140	larl	%r3,.Lorb		# r2 = address of orb into r2
141	larl	%r5,.Lirb		# r4 = address of irb
142	larl	%r6,.Lccws
143	lghi	%r7,20
144.Linit:
145	st	%r2,4(%r6)		# initialize CCW data addresses
146	la	%r2,0x50(%r2)
147	la	%r6,8(%r6)
148	brctg	%r7,.Linit
149	larl	%r13,.Lcr6
150	lctlg	%c6,%c6,0(%r13)
151	xgr	%r2,%r2
152.Lldlp:
153	ssch	0(%r3)			# load chunk of 1600 bytes
154	jnz	.Llderr
155.Lwait4irq:
156	bras	%r14,.Lirqwait
157	c	%r1,__LC_SUBCHANNEL_ID	# compare subchannel number
158	jne	.Lwait4irq
159	tsch	0(%r5)
160	xgr	%r0,%r0
161	ic	%r0,8(%r5)		# get device status
162	cghi	%r0,8			# channel end ?
163	je	.Lcont
164	cghi	%r0,12			# channel end + device end ?
165	je	.Lcont
166	llgf	%r0,4(%r5)
167	sgf	%r0,8(%r3)		# r0/8 = number of ccws executed
168	mghi	%r0,10			# *10 = number of bytes in ccws
169	llgh	%r3,10(%r5)		# get residual count
170	sgr	%r0,%r3			# #ccws*80-residual=#bytes read
171	agr	%r2,%r0
172	br	%r4			# r2 contains the total size
173.Lcont:
174	aghi	%r2,0x640		# add 0x640 to total size
175	larl	%r6,.Lccws
176	lghi	%r7,20
177.Lincr:
178	l	%r0,4(%r6)		# update CCW data addresses
179	aghi	%r0,0x640
180	st	%r0,4(%r6)
181	aghi	%r6,8
182	brctg	%r7,.Lincr
183	j	.Lldlp
184.Llderr:
185	larl	%r13,.Lcrash
186	lpsw	0(%r13)
187
188	.balign	8
189.Lwaitpsw:
190	.quad	0x0202000180000000,.Lioint
191.Lnewpswmask:
192	.quad	0x0000000180000000
193	.balign	8
194.Lorb:	.long	0x00000000,0x0080ff00,.Lccws
195.Lirb:	.long	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
196	.balign	8
197.Lcr6:	.quad	0x00000000ff000000
198	.balign	8
199.Lcrash:.long	0x000a0000,0x00000000
200	.balign	8
201.Lccws: .rept	19
202	.long	0x02600050,0x00000000
203	.endr
204	.long	0x02200050,0x00000000
205.Lreset:.byte	0xc3,0xc8,0xc1,0xd5,0xc7,0xc5,0x40,0xd9,0xc4,0xd9,0x40
206	.byte	0xc1,0xd3,0xd3,0x40,0xd2,0xc5,0xc5,0xd7,0x40,0xd5,0xd6
207	.byte	0xc8,0xd6,0xd3,0xc4	# "change rdr all keep nohold"
208.L_eof: .long	0xc5d6c600	 /* C'EOF' */
209.L_hdr: .long	0xc8c4d900	 /* C'HDR' */
210	.balign	8
211.Lcpuid:.fill	8,1,0
212
213#
214# normal startup-code, running in absolute addressing mode
215# this is called either by the ipl loader or directly by PSW restart
216# or linload or SALIPL
217#
218	.org	STARTUP_NORMAL_OFFSET - IPL_START
219SYM_CODE_START(startup)
220	j	startup_normal
221	.org	EP_OFFSET - IPL_START
222#
223# This is a list of s390 kernel entry points. At address 0x1000f the number of
224# valid entry points is stored.
225#
226# IMPORTANT: Do not change this table, it is s390 kernel ABI!
227#
228	.ascii	EP_STRING
229	.byte	0x00,0x01
230#
231# kdump startup-code, running in 64 bit absolute addressing mode
232#
233	.org	STARTUP_KDUMP_OFFSET - IPL_START
234	j	startup_kdump
235SYM_CODE_END(startup)
236SYM_CODE_START_LOCAL(startup_normal)
237	mvi	__LC_AR_MODE_ID,1	# set esame flag
238	slr	%r0,%r0 		# set cpuid to zero
239	lhi	%r1,2			# mode 2 = esame (dump)
240	sigp	%r1,%r0,0x12		# switch to esame mode
241	bras	%r13,0f
242	.fill	16,4,0x0
2430:	lmh	%r0,%r15,0(%r13)	# clear high-order half of gprs
244	sam64				# switch to 64 bit addressing mode
245	larl	%r13,.Lext_new_psw
246	mvc	__LC_EXT_NEW_PSW(16),0(%r13)
247	larl	%r13,.Lpgm_new_psw
248	mvc	__LC_PGM_NEW_PSW(16),0(%r13)
249	larl	%r13,.Lio_new_psw
250	mvc	__LC_IO_NEW_PSW(16),0(%r13)
251	xc	0x200(256),0x200	# partially clear lowcore
252	xc	0x300(256),0x300
253	xc	0xe00(256),0xe00
254	xc	0xf00(256),0xf00
255	larl	%r13,.Lctl
256	lctlg	%c0,%c15,0(%r13)	# load control registers
257	stcke	__LC_BOOT_CLOCK
258	mvc	__LC_LAST_UPDATE_CLOCK(8),__LC_BOOT_CLOCK+1
259	larl	%r13,6f
260	spt	0(%r13)
261	mvc	__LC_LAST_UPDATE_TIMER(8),0(%r13)
262	larl	%r15,_stack_end-STACK_FRAME_OVERHEAD
263	brasl	%r14,sclp_early_setup_buffer
264	brasl	%r14,verify_facilities
265	brasl	%r14,startup_kernel
266SYM_CODE_END(startup_normal)
267
268	.balign	8
2696:	.long	0x7fffffff,0xffffffff
270.Lext_new_psw:
271	.quad	0x0002000180000000,0x1b0	# disabled wait
272.Lpgm_new_psw:
273	.quad	0x0000000180000000,startup_pgm_check_handler
274.Lio_new_psw:
275	.quad	0x0002000180000000,0x1f0	# disabled wait
276.Lctl:	.quad	0x04040000		# cr0: AFP registers & secondary space
277	.quad	0			# cr1: primary space segment table
278	.quad	0			# cr2: dispatchable unit control table
279	.quad	0			# cr3: instruction authorization
280	.quad	0xffff			# cr4: instruction authorization
281	.quad	0			# cr5: primary-aste origin
282	.quad	0			# cr6:	I/O interrupts
283	.quad	0			# cr7:	secondary space segment table
284	.quad	0x0000000000008000	# cr8:	access registers translation
285	.quad	0			# cr9:	tracing off
286	.quad	0			# cr10: tracing off
287	.quad	0			# cr11: tracing off
288	.quad	0			# cr12: tracing off
289	.quad	0			# cr13: home space segment table
290	.quad	0xc0000000		# cr14: machine check handling off
291	.quad	0			# cr15: linkage stack operations
292
293#include "head_kdump.S"
294
295#
296# This program check is active immediately after kernel start
297# and until early_pgm_check_handler is set in kernel/early.c
298# It simply saves general/control registers and psw in
299# the save area and does disabled wait with a faulty address.
300#
301SYM_CODE_START_LOCAL(startup_pgm_check_handler)
302	stmg	%r8,%r15,__LC_SAVE_AREA_SYNC
303	la	%r8,4095
304	stctg	%c0,%c15,__LC_CREGS_SAVE_AREA-4095(%r8)
305	stmg	%r0,%r7,__LC_GPREGS_SAVE_AREA-4095(%r8)
306	mvc	__LC_GPREGS_SAVE_AREA-4095+64(64,%r8),__LC_SAVE_AREA_SYNC
307	mvc	__LC_PSW_SAVE_AREA-4095(16,%r8),__LC_PGM_OLD_PSW
308	mvc	__LC_RETURN_PSW(16),__LC_PGM_OLD_PSW
309	ni	__LC_RETURN_PSW,0xfc	# remove IO and EX bits
310	ni	__LC_RETURN_PSW+1,0xfb	# remove MCHK bit
311	oi	__LC_RETURN_PSW+1,0x2	# set wait state bit
312	larl	%r9,.Lold_psw_disabled_wait
313	stg	%r9,__LC_PGM_NEW_PSW+8
314	larl	%r15,_dump_info_stack_end-STACK_FRAME_OVERHEAD
315	brasl	%r14,print_pgm_check_info
316.Lold_psw_disabled_wait:
317	la	%r8,4095
318	lmg	%r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r8)
319	lpswe	__LC_RETURN_PSW		# disabled wait
320SYM_CODE_END(startup_pgm_check_handler)
321