xref: /linux/arch/s390/kernel/head64.S (revision 13abf8130139c2ccd4962a7e5a8902be5e6cb5a7)
1/*
2 *  arch/s390/kernel/head.S
3 *
4 *  S390 version
5 *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
6 *    Author(s): Hartmut Penner (hp@de.ibm.com),
7 *               Martin Schwidefsky (schwidefsky@de.ibm.com),
8 *               Rob van der Heij (rvdhei@iae.nl)
9 *
10 * There are 5 different IPL methods
11 *  1) load the image directly into ram at address 0 and do an PSW restart
12 *  2) linload will load the image from address 0x10000 to memory 0x10000
13 *     and start the code thru LPSW 0x0008000080010000 (VM only, deprecated)
14 *  3) generate the tape ipl header, store the generated image on a tape
15 *     and ipl from it
16 *     In case of SL tape you need to IPL 5 times to get past VOL1 etc
17 *  4) generate the vm reader ipl header, move the generated image to the
18 *     VM reader (use option NOH!) and do a ipl from reader (VM only)
19 *  5) direct call of start by the SALIPL loader
20 *  We use the cpuid to distinguish between VM and native ipl
21 *  params for kernel are pushed to 0x10400 (see setup.h)
22
23    Changes:
24    Okt 25 2000 <rvdheij@iae.nl>
25	added code to skip HDR and EOF to allow SL tape IPL (5 retries)
26	changed first CCW from rewind to backspace block
27
28 */
29
30#include <linux/config.h>
31#include <asm/setup.h>
32#include <asm/lowcore.h>
33#include <asm/offsets.h>
34#include <asm/thread_info.h>
35#include <asm/page.h>
36
37#ifndef CONFIG_IPL
38        .org   0
39        .long  0x00080000,0x80000000+startup   # Just a restart PSW
40#else
41#ifdef CONFIG_IPL_TAPE
42#define IPL_BS 1024
43        .org   0
44        .long  0x00080000,0x80000000+iplstart  # The first 24 bytes are loaded
45        .long  0x27000000,0x60000001           # by ipl to addresses 0-23.
46        .long  0x02000000,0x20000000+IPL_BS    # (a PSW and two CCWs).
47        .long  0x00000000,0x00000000           # external old psw
48        .long  0x00000000,0x00000000           # svc old psw
49        .long  0x00000000,0x00000000           # program check old psw
50        .long  0x00000000,0x00000000           # machine check old psw
51        .long  0x00000000,0x00000000           # io old psw
52        .long  0x00000000,0x00000000
53        .long  0x00000000,0x00000000
54        .long  0x00000000,0x00000000
55        .long  0x000a0000,0x00000058           # external new psw
56        .long  0x000a0000,0x00000060           # svc new psw
57        .long  0x000a0000,0x00000068           # program check new psw
58        .long  0x000a0000,0x00000070           # machine check new psw
59        .long  0x00080000,0x80000000+.Lioint   # io new psw
60
61        .org   0x100
62#
63# subroutine for loading from tape
64# Paramters:
65#  R1 = device number
66#  R2 = load address
67.Lloader:
68        st    %r14,.Lldret
69        la    %r3,.Lorbread                    # r3 = address of orb
70	la    %r5,.Lirb                        # r5 = address of irb
71        st    %r2,.Lccwread+4                  # initialize CCW data addresses
72        lctl  %c6,%c6,.Lcr6
73        slr   %r2,%r2
74.Lldlp:
75        la    %r6,3                            # 3 retries
76.Lssch:
77        ssch  0(%r3)                           # load chunk of IPL_BS bytes
78        bnz   .Llderr
79.Lw4end:
80        bas   %r14,.Lwait4io
81        tm    8(%r5),0x82                      # do we have a problem ?
82        bnz   .Lrecov
83        slr   %r7,%r7
84        icm   %r7,3,10(%r5)                    # get residual count
85        lcr   %r7,%r7
86        la    %r7,IPL_BS(%r7)                  # IPL_BS-residual=#bytes read
87        ar    %r2,%r7                          # add to total size
88        tm    8(%r5),0x01                      # found a tape mark ?
89        bnz   .Ldone
90        l     %r0,.Lccwread+4                  # update CCW data addresses
91        ar    %r0,%r7
92        st    %r0,.Lccwread+4
93        b     .Lldlp
94.Ldone:
95        l     %r14,.Lldret
96        br    %r14                             # r2 contains the total size
97.Lrecov:
98        bas   %r14,.Lsense                     # do the sensing
99        bct   %r6,.Lssch                       # dec. retry count & branch
100        b     .Llderr
101#
102# Sense subroutine
103#
104.Lsense:
105        st    %r14,.Lsnsret
106        la    %r7,.Lorbsense
107        ssch  0(%r7)                           # start sense command
108        bnz   .Llderr
109        bas   %r14,.Lwait4io
110        l     %r14,.Lsnsret
111        tm    8(%r5),0x82                      # do we have a problem ?
112        bnz   .Llderr
113        br    %r14
114#
115# Wait for interrupt subroutine
116#
117.Lwait4io:
118        lpsw  .Lwaitpsw
119.Lioint:
120        c     %r1,0xb8                         # compare subchannel number
121        bne   .Lwait4io
122        tsch  0(%r5)
123        slr   %r0,%r0
124        tm    8(%r5),0x82                      # do we have a problem ?
125        bnz   .Lwtexit
126        tm    8(%r5),0x04                      # got device end ?
127        bz    .Lwait4io
128.Lwtexit:
129        br    %r14
130.Llderr:
131        lpsw  .Lcrash
132
133        .align 8
134.Lorbread:
135	.long  0x00000000,0x0080ff00,.Lccwread
136        .align 8
137.Lorbsense:
138        .long  0x00000000,0x0080ff00,.Lccwsense
139        .align 8
140.Lccwread:
141        .long  0x02200000+IPL_BS,0x00000000
142.Lccwsense:
143        .long  0x04200001,0x00000000
144.Lwaitpsw:
145	.long  0x020a0000,0x80000000+.Lioint
146
147.Lirb:	.long  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
148.Lcr6:  .long  0xff000000
149        .align 8
150.Lcrash:.long  0x000a0000,0x00000000
151.Lldret:.long  0
152.Lsnsret: .long 0
153#endif  /* CONFIG_IPL_TAPE */
154
155#ifdef CONFIG_IPL_VM
156#define IPL_BS 0x730
157        .org   0
158        .long  0x00080000,0x80000000+iplstart  # The first 24 bytes are loaded
159        .long  0x02000018,0x60000050           # by ipl to addresses 0-23.
160        .long  0x02000068,0x60000050           # (a PSW and two CCWs).
161        .fill  80-24,1,0x40                    # bytes 24-79 are discarded !!
162        .long  0x020000f0,0x60000050           # The next 160 byte are loaded
163        .long  0x02000140,0x60000050           # to addresses 0x18-0xb7
164        .long  0x02000190,0x60000050           # They form the continuation
165        .long  0x020001e0,0x60000050           # of the CCW program started
166        .long  0x02000230,0x60000050           # by ipl and load the range
167        .long  0x02000280,0x60000050           # 0x0f0-0x730 from the image
168        .long  0x020002d0,0x60000050           # to the range 0x0f0-0x730
169        .long  0x02000320,0x60000050           # in memory. At the end of
170        .long  0x02000370,0x60000050           # the channel program the PSW
171        .long  0x020003c0,0x60000050           # at location 0 is loaded.
172        .long  0x02000410,0x60000050           # Initial processing starts
173        .long  0x02000460,0x60000050           # at 0xf0 = iplstart.
174        .long  0x020004b0,0x60000050
175        .long  0x02000500,0x60000050
176        .long  0x02000550,0x60000050
177        .long  0x020005a0,0x60000050
178        .long  0x020005f0,0x60000050
179        .long  0x02000640,0x60000050
180        .long  0x02000690,0x60000050
181        .long  0x020006e0,0x20000050
182
183        .org   0xf0
184#
185# subroutine for loading cards from the reader
186#
187.Lloader:
188	la    %r3,.Lorb                        # r2 = address of orb into r2
189	la    %r5,.Lirb                        # r4 = address of irb
190        la    %r6,.Lccws
191        la    %r7,20
192.Linit:
193        st    %r2,4(%r6)                       # initialize CCW data addresses
194        la    %r2,0x50(%r2)
195        la    %r6,8(%r6)
196        bct   7,.Linit
197
198        lctl  %c6,%c6,.Lcr6                    # set IO subclass mask
199	slr   %r2,%r2
200.Lldlp:
201        ssch  0(%r3)                           # load chunk of 1600 bytes
202        bnz   .Llderr
203.Lwait4irq:
204        mvc   0x78(8),.Lnewpsw                 # set up IO interrupt psw
205        lpsw  .Lwaitpsw
206.Lioint:
207        c     %r1,0xb8                         # compare subchannel number
208	bne   .Lwait4irq
209	tsch  0(%r5)
210
211	slr   %r0,%r0
212	ic    %r0,8(%r5)                       # get device status
213	chi   %r0,8                            # channel end ?
214	be    .Lcont
215	chi   %r0,12                           # channel end + device end ?
216	be    .Lcont
217
218        l     %r0,4(%r5)
219        s     %r0,8(%r3)                       # r0/8 = number of ccws executed
220        mhi   %r0,10                           # *10 = number of bytes in ccws
221        lh    %r3,10(%r5)                      # get residual count
222        sr    %r0,%r3                          # #ccws*80-residual=#bytes read
223	ar    %r2,%r0
224
225        br    %r14                             # r2 contains the total size
226
227.Lcont:
228	ahi   %r2,0x640                        # add 0x640 to total size
229        la    %r6,.Lccws
230        la    %r7,20
231.Lincr:
232        l     %r0,4(%r6)                       # update CCW data addresses
233        ahi   %r0,0x640
234        st    %r0,4(%r6)
235        ahi   %r6,8
236        bct   7,.Lincr
237
238        b     .Lldlp
239.Llderr:
240        lpsw  .Lcrash
241
242        .align 8
243.Lorb:	.long  0x00000000,0x0080ff00,.Lccws
244.Lirb:	.long  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
245.Lcr6:  .long  0xff000000
246.Lloadp:.long  0,0
247        .align 8
248.Lcrash:.long  0x000a0000,0x00000000
249.Lnewpsw:
250        .long  0x00080000,0x80000000+.Lioint
251.Lwaitpsw:
252        .long  0x020a0000,0x80000000+.Lioint
253
254        .align 8
255.Lccws: .rept  19
256        .long  0x02600050,0x00000000
257        .endr
258        .long  0x02200050,0x00000000
259#endif  /* CONFIG_IPL_VM */
260
261iplstart:
262        lh    %r1,0xb8                         # test if subchannel number
263        bct   %r1,.Lnoload                     #  is valid
264	l     %r1,0xb8                         # load ipl subchannel number
265        la    %r2,IPL_BS                       # load start address
266        bas   %r14,.Lloader                    # load rest of ipl image
267        larl  %r12,_pstart                     # pointer to parameter area
268        st    %r1,IPL_DEVICE+4-PARMAREA(%r12)  # store ipl device number
269
270#
271# load parameter file from ipl device
272#
273.Lagain1:
274 	l     %r2,INITRD_START+4-PARMAREA(%r12)# use ramdisk location as temp
275        bas   %r14,.Lloader                    # load parameter file
276        ltr   %r2,%r2                          # got anything ?
277        bz    .Lnopf
278	chi   %r2,895
279	bnh   .Lnotrunc
280	la    %r2,895
281.Lnotrunc:
282	l     %r4,INITRD_START+4-PARMAREA(%r12)
283 	clc   0(3,%r4),.L_hdr		       # if it is HDRx
284 	bz    .Lagain1			       # skip dataset header
285 	clc   0(3,%r4),.L_eof		       # if it is EOFx
286 	bz    .Lagain1			       # skip dateset trailer
287        la    %r5,0(%r4,%r2)
288        lr    %r3,%r2
289.Lidebc:
290        tm    0(%r5),0x80                      # high order bit set ?
291        bo    .Ldocv                           #  yes -> convert from EBCDIC
292        ahi   %r5,-1
293        bct   %r3,.Lidebc
294        b     .Lnocv
295.Ldocv:
296        l     %r3,.Lcvtab
297        tr    0(256,%r4),0(%r3)                # convert parameters to ascii
298        tr    256(256,%r4),0(%r3)
299        tr    512(256,%r4),0(%r3)
300        tr    768(122,%r4),0(%r3)
301.Lnocv: la    %r3,COMMAND_LINE-PARMAREA(%r12)  # load adr. of command line
302	mvc   0(256,%r3),0(%r4)
303	mvc   256(256,%r3),256(%r4)
304	mvc   512(256,%r3),512(%r4)
305	mvc   768(122,%r3),768(%r4)
306        slr   %r0,%r0
307        b     .Lcntlp
308.Ldelspc:
309        ic    %r0,0(%r2,%r3)
310        chi   %r0,0x20                         # is it a space ?
311        be    .Lcntlp
312        ahi   %r2,1
313        b     .Leolp
314.Lcntlp:
315        brct  %r2,.Ldelspc
316.Leolp:
317        slr   %r0,%r0
318        stc   %r0,0(%r2,%r3)                   # terminate buffer
319.Lnopf:
320
321#
322# load ramdisk from ipl device
323#
324.Lagain2:
325 	l     %r2,INITRD_START+4-PARMAREA(%r12)# load adr. of ramdisk
326        bas   %r14,.Lloader                    # load ramdisk
327 	st    %r2,INITRD_SIZE+4-PARMAREA(%r12) # store size of ramdisk
328        ltr   %r2,%r2
329        bnz   .Lrdcont
330        st    %r2,INITRD_START+4-PARMAREA(%r12)# no ramdisk found, null it
331.Lrdcont:
332	l     %r2,INITRD_START+4-PARMAREA(%r12)
333	clc   0(3,%r2),.L_hdr		       # skip HDRx and EOFx
334	bz    .Lagain2
335	clc   0(3,%r2),.L_eof
336	bz    .Lagain2
337
338#ifdef CONFIG_IPL_VM
339#
340# reset files in VM reader
341#
342        stidp __LC_CPUID                       # store cpuid
343	tm    __LC_CPUID,0xff                  # running VM ?
344	bno   .Lnoreset
345        la    %r2,.Lreset
346        lhi   %r3,26
347	diag  %r2,%r3,8
348	la    %r5,.Lirb
349	stsch 0(%r5)			       # check if irq is pending
350	tm    30(%r5),0x0f		       # by verifying if any of the
351	bnz   .Lwaitforirq		       # activity or status control
352	tm    31(%r5),0xff		       # bits is set in the schib
353	bz    .Lnoreset
354.Lwaitforirq:
355	mvc   0x78(8),.Lrdrnewpsw	       # set up IO interrupt psw
356.Lwaitrdrirq:
357	lpsw  .Lrdrwaitpsw
358.Lrdrint:
359	c     %r1,0xb8			       # compare subchannel number
360	bne   .Lwaitrdrirq
361	la    %r5,.Lirb
362	tsch  0(%r5)
363.Lnoreset:
364	b     .Lnoload
365
366	.align 8
367.Lrdrnewpsw:
368	.long  0x00080000,0x80000000+.Lrdrint
369.Lrdrwaitpsw:
370	.long  0x020a0000,0x80000000+.Lrdrint
371#endif
372
373#
374# everything loaded, go for it
375#
376.Lnoload:
377        l     %r1,.Lstartup
378        br    %r1
379
380.Lstartup: .long startup
381.Lcvtab:.long  _ebcasc                         # ebcdic to ascii table
382.Lreset:.byte  0xc3,0xc8,0xc1,0xd5,0xc7,0xc5,0x40,0xd9,0xc4,0xd9,0x40
383        .byte  0xc1,0xd3,0xd3,0x40,0xd2,0xc5,0xc5,0xd7,0x40,0xd5,0xd6
384        .byte  0xc8,0xd6,0xd3,0xc4             # "change rdr all keep nohold"
385.L_eof: .long  0xc5d6c600       /* C'EOF' */
386.L_hdr: .long  0xc8c4d900       /* C'HDR' */
387#endif  /* CONFIG_IPL */
388
389#
390# SALIPL loader support. Based on a patch by Rob van der Heij.
391# This entry point is called directly from the SALIPL loader and
392# doesn't need a builtin ipl record.
393#
394        .org  0x800
395	.globl start
396start:
397	stm   %r0,%r15,0x07b0		# store registers
398	basr  %r12,%r0
399.base:
400	l     %r11,.parm
401	l     %r8,.cmd			# pointer to command buffer
402
403	ltr   %r9,%r9			# do we have SALIPL parameters?
404	bp    .sk8x8
405
406	mvc   0(64,%r8),0x00b0		# copy saved registers
407	xc    64(240-64,%r8),0(%r8)	# remainder of buffer
408	tr    0(64,%r8),.lowcase
409	b     .gotr
410.sk8x8:
411	mvc   0(240,%r8),0(%r9)		# copy iplparms into buffer
412.gotr:
413	l     %r10,.tbl			# EBCDIC to ASCII table
414	tr    0(240,%r8),0(%r10)
415	stidp __LC_CPUID		# Are we running on VM maybe
416	cli   __LC_CPUID,0xff
417	bnz   .test
418	.long 0x83300060		# diag 3,0,x'0060' - storage size
419	b     .done
420.test:
421	mvc   0x68(8),.pgmnw		# set up pgm check handler
422	l     %r2,.fourmeg
423	lr    %r3,%r2
424	bctr  %r3,%r0			# 4M-1
425.loop:  iske  %r0,%r3
426	ar    %r3,%r2
427.pgmx:
428	sr    %r3,%r2
429	la    %r3,1(%r3)
430.done:
431	l     %r1,.memsize
432	st    %r3,4(%r1)
433	slr   %r0,%r0
434	st    %r0,INITRD_SIZE+4-PARMAREA(%r11)
435	st    %r0,INITRD_START+4-PARMAREA(%r11)
436	j     startup                   # continue with startup
437.tbl:	.long _ebcasc			# translate table
438.cmd:	.long COMMAND_LINE		# address of command line buffer
439.parm:	.long PARMAREA
440.fourmeg: .long 0x00400000      	# 4M
441.pgmnw:	.long 0x00080000,.pgmx
442.memsize: .long memory_size
443.lowcase:
444	.byte 0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07
445	.byte 0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f
446	.byte 0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17
447	.byte 0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f
448	.byte 0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27
449	.byte 0x28,0x29,0x2a,0x2b,0x2c,0x2d,0x2e,0x2f
450	.byte 0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37
451	.byte 0x38,0x39,0x3a,0x3b,0x3c,0x3d,0x3e,0x3f
452	.byte 0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47
453	.byte 0x48,0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f
454	.byte 0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57
455	.byte 0x58,0x59,0x5a,0x5b,0x5c,0x5d,0x5e,0x5f
456	.byte 0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67
457	.byte 0x68,0x69,0x6a,0x6b,0x6c,0x6d,0x6e,0x6f
458	.byte 0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77
459	.byte 0x78,0x79,0x7a,0x7b,0x7c,0x7d,0x7e,0x7f
460
461	.byte 0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87
462	.byte 0x88,0x89,0x8a,0x8b,0x8c,0x8d,0x8e,0x8f
463	.byte 0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97
464	.byte 0x98,0x99,0x9a,0x9b,0x9c,0x9d,0x9e,0x9f
465	.byte 0xa0,0xa1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7
466	.byte 0xa8,0xa9,0xaa,0xab,0xac,0xad,0xae,0xaf
467	.byte 0xb0,0xb1,0xb2,0xb3,0xb4,0xb5,0xb6,0xb7
468	.byte 0xb8,0xb9,0xba,0xbb,0xbc,0xbd,0xbe,0xbf
469	.byte 0xc0,0x81,0x82,0x83,0x84,0x85,0x86,0x87	# .abcdefg
470	.byte 0x88,0x89,0xca,0xcb,0xcc,0xcd,0xce,0xcf	# hi
471	.byte 0xd0,0x91,0x92,0x93,0x94,0x95,0x96,0x97 	# .jklmnop
472	.byte 0x98,0x99,0xda,0xdb,0xdc,0xdd,0xde,0xdf	# qr
473	.byte 0xe0,0xe1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7	# ..stuvwx
474	.byte 0xa8,0xa9,0xea,0xeb,0xec,0xed,0xee,0xef	# yz
475	.byte 0xf0,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7
476	.byte 0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfe,0xff
477
478#
479# startup-code at 0x10000, running in real mode
480# this is called either by the ipl loader or directly by PSW restart
481# or linload or SALIPL
482#
483        .org  0x10000
484startup:basr  %r13,0                     # get base
485.LPG1:  sll   %r13,1                     # remove high order bit
486        srl   %r13,1
487        lhi   %r1,1                      # mode 1 = esame
488        slr   %r0,%r0                    # set cpuid to zero
489        sigp  %r1,%r0,0x12               # switch to esame mode
490	sam64				 # switch to 64 bit mode
491	lctlg %c0,%c15,.Lctl-.LPG1(%r13) # load control registers
492	larl  %r12,_pstart               # pointer to parameter area
493					 # move IPL device to lowcore
494        mvc   __LC_IPLDEV(4),IPL_DEVICE+4-PARMAREA(%r12)
495
496#
497# clear bss memory
498#
499	larl  %r2,__bss_start           # start of bss segment
500        larl  %r3,_end                  # end of bss segment
501        sgr   %r3,%r2                   # length of bss
502        sgr   %r4,%r4                   #
503        sgr   %r5,%r5                   # set src,length and pad to zero
504        mvcle %r2,%r4,0                 # clear mem
505        jo    .-4                       # branch back, if not finish
506
507	l     %r2,.Lrcp-.LPG1(%r13)	# Read SCP forced command word
508.Lservicecall:
509	stosm .Lpmask-.LPG1(%r13),0x01	# authorize ext interrupts
510
511	stctg %r0,%r0,.Lcr-.LPG1(%r13)	# get cr0
512	la    %r1,0x200			# set bit 22
513	og    %r1,.Lcr-.LPG1(%r13)	# or old cr0 with r1
514	stg   %r1,.Lcr-.LPG1(%r13)
515	lctlg %r0,%r0,.Lcr-.LPG1(%r13)	# load modified cr0
516
517	mvc   __LC_EXT_NEW_PSW(8),.Lpcmsk-.LPG1(%r13) # set postcall psw
518	larl  %r1,.Lsclph
519	stg   %r1,__LC_EXT_NEW_PSW+8	# set handler
520
521	larl  %r4,_pstart		# %r4 is our index for sccb stuff
522	la    %r1,.Lsccb-PARMAREA(%r4)	# our sccb
523	.insn rre,0xb2200000,%r2,%r1	# service call
524	ipm   %r1
525	srl   %r1,28			# get cc code
526	xr    %r3,%r3
527	chi   %r1,3
528	be    .Lfchunk-.LPG1(%r13)	# leave
529	chi   %r1,2
530	be    .Lservicecall-.LPG1(%r13)
531	lpsw  .Lwaitsclp-.LPG1(%r13)
532.Lsclph:
533	lh    %r1,.Lsccbr-PARMAREA(%r4)
534	chi   %r1,0x10			# 0x0010 is the sucess code
535	je    .Lprocsccb		# let's process the sccb
536	chi   %r1,0x1f0
537	bne   .Lfchunk-.LPG1(%r13)	# unhandled error code
538	c     %r2,.Lrcp-.LPG1(%r13)	# Did we try Read SCP forced
539	bne   .Lfchunk-.LPG1(%r13)	# if no, give up
540	l     %r2,.Lrcp2-.LPG1(%r13)	# try with Read SCP
541	b     .Lservicecall-.LPG1(%r13)
542.Lprocsccb:
543	lghi  %r1,0
544	icm   %r1,3,.Lscpincr1-PARMAREA(%r4) # use this one if != 0
545	jnz   .Lscnd
546	lg    %r1,.Lscpincr2-PARMAREA(%r4) # otherwise use this one
547.Lscnd:
548	xr    %r3,%r3			# same logic
549	ic    %r3,.Lscpa1-PARMAREA(%r4)
550	chi   %r3,0x00
551	jne   .Lcompmem
552	l     %r3,.Lscpa2-PARMAREA(%r13)
553.Lcompmem:
554	mlgr  %r2,%r1			# mem in MB on 128-bit
555	l     %r1,.Lonemb-.LPG1(%r13)
556	mlgr  %r2,%r1			# mem size in bytes in %r3
557	b     .Lfchunk-.LPG1(%r13)
558
559.Lpmask:
560	.byte 0
561	.align 8
562.Lcr:
563	.quad 0x00  # place holder for cr0
564.Lwaitsclp:
565	.long 0x020A0000
566	.quad .Lsclph
567.Lrcp:
568	.int 0x00120001 # Read SCP forced code
569.Lrcp2:
570	.int 0x00020001 # Read SCP code
571.Lonemb:
572	.int 0x100000
573
574.Lfchunk:
575					 # set program check new psw mask
576	mvc   __LC_PGM_NEW_PSW(8),.Lpcmsk-.LPG1(%r13)
577
578#
579# find memory chunks.
580#
581	lgr   %r9,%r3			 # end of mem
582	larl  %r1,.Lchkmem               # set program check address
583	stg   %r1,__LC_PGM_NEW_PSW+8
584	la    %r1,1                      # test in increments of 128KB
585	sllg  %r1,%r1,17
586	larl  %r3,memory_chunk
587	slgr  %r4,%r4                    # set start of chunk to zero
588	slgr  %r5,%r5                    # set end of chunk to zero
589	slr  %r6,%r6			 # set access code to zero
590	la    %r10,MEMORY_CHUNKS	 # number of chunks
591.Lloop:
592	tprot 0(%r5),0			 # test protection of first byte
593	ipm   %r7
594	srl   %r7,28
595	clr   %r6,%r7			 # compare cc with last access code
596	je    .Lsame
597	j     .Lchkmem
598.Lsame:
599	algr  %r5,%r1			 # add 128KB to end of chunk
600					 # no need to check here,
601	brc   12,.Lloop			 # this is the same chunk
602.Lchkmem:				 # > 16EB or tprot got a program check
603	clgr  %r4,%r5			 # chunk size > 0?
604	je    .Lchkloop
605	stg   %r4,0(%r3)		 # store start address of chunk
606	lgr   %r0,%r5
607	slgr  %r0,%r4
608	stg   %r0,8(%r3)		 # store size of chunk
609	st    %r6,20(%r3)		 # store type of chunk
610	la    %r3,24(%r3)
611	larl  %r8,memory_size
612	stg   %r5,0(%r8)                 # store memory size
613	ahi   %r10,-1			 # update chunk number
614.Lchkloop:
615	lr    %r6,%r7			 # set access code to last cc
616	# we got an exception or we're starting a new
617	# chunk , we must check if we should
618	# still try to find valid memory (if we detected
619	# the amount of available storage), and if we
620	# have chunks left
621	lghi  %r4,1
622	sllg  %r4,%r4,31
623	clgr  %r5,%r4
624	je    .Lhsaskip
625	xr    %r0, %r0
626	clgr  %r0, %r9			 # did we detect memory?
627	je    .Ldonemem			 # if not, leave
628	chi   %r10, 0			 # do we have chunks left?
629	je    .Ldonemem
630.Lhsaskip:
631	algr  %r5,%r1			 # add 128KB to end of chunk
632	lgr   %r4,%r5			 # potential new chunk
633	clgr  %r5,%r9			 # should we go on?
634	jl    .Lloop
635.Ldonemem:
636
637	larl  %r12,machine_flags
638#
639# find out if we are running under VM
640#
641        stidp  __LC_CPUID               # store cpuid
642	tm     __LC_CPUID,0xff          # running under VM ?
643	bno    0f-.LPG1(%r13)
644        oi     7(%r12),1                # set VM flag
6450:      lh     %r0,__LC_CPUID+4         # get cpu version
646        chi    %r0,0x7490               # running on a P/390 ?
647        bne    1f-.LPG1(%r13)
648        oi     7(%r12),4                # set P/390 flag
6491:
650
651#
652# find out if we have the MVPG instruction
653#
654	la     %r1,0f-.LPG1(%r13)       # set program check address
655	stg    %r1,__LC_PGM_NEW_PSW+8
656	sgr    %r0,%r0
657	lghi   %r1,0
658	lghi   %r2,0
659	mvpg   %r1,%r2                  # test MVPG instruction
660	oi     7(%r12),16               # set MVPG flag
6610:
662
663#
664# find out if the diag 0x44 works in 64 bit mode
665#
666	la     %r1,0f-.LPG1(%r13)	# set program check address
667	stg    %r1,__LC_PGM_NEW_PSW+8
668	diag   0,0,0x44			# test diag 0x44
669	oi     7(%r12),32		# set diag44 flag
6700:
671
672#
673# find out if we have the IDTE instruction
674#
675	la     %r1,0f-.LPG1(%r13)	# set program check address
676	stg    %r1,__LC_PGM_NEW_PSW+8
677	.long	0xb2b10000		# store facility list
678	tm	0xc8,0x08		# check bit for clearing-by-ASCE
679	bno	0f-.LPG1(%r13)
680	lhi	%r1,2094
681	lhi	%r2,0
682	.long	0xb98e2001
683	oi	7(%r12),0x80		# set IDTE flag
6840:
685
686        lpswe .Lentry-.LPG1(13)         # jump to _stext in primary-space,
687                                        # virtual and never return ...
688        .align 16
689.Lentry:.quad  0x0000000180000000,_stext
690.Lctl:  .quad  0x04b50002               # cr0: various things
691        .quad  0                        # cr1: primary space segment table
692        .quad  .Lduct                   # cr2: dispatchable unit control table
693        .quad  0                        # cr3: instruction authorization
694        .quad  0                        # cr4: instruction authorization
695        .quad  0xffffffffffffffff       # cr5: primary-aste origin
696        .quad  0                        # cr6:  I/O interrupts
697        .quad  0                        # cr7:  secondary space segment table
698        .quad  0                        # cr8:  access registers translation
699        .quad  0                        # cr9:  tracing off
700        .quad  0                        # cr10: tracing off
701        .quad  0                        # cr11: tracing off
702        .quad  0                        # cr12: tracing off
703        .quad  0                        # cr13: home space segment table
704        .quad  0xc0000000               # cr14: machine check handling off
705        .quad  0                        # cr15: linkage stack operations
706.Lpcmsk:.quad  0x0000000180000000
707.L4malign:.quad 0xffffffffffc00000
708.Lscan2g:.quad 0x80000000 + 0x20000 - 8 # 2GB + 128K - 8
709.Lnop:	.long  0x07000700
710
711	.org PARMAREA-64
712.Lduct:	.long 0,0,0,0,0,0,0,0
713	.long 0,0,0,0,0,0,0,0
714
715#
716# params at 10400 (setup.h)
717#
718	.org   PARMAREA
719	.global _pstart
720_pstart:
721	.quad  0                        # IPL_DEVICE
722        .quad  RAMDISK_ORIGIN           # INITRD_START
723        .quad  RAMDISK_SIZE             # INITRD_SIZE
724
725        .org   COMMAND_LINE
726    	.byte  "root=/dev/ram0 ro"
727        .byte  0
728	.org   0x11000
729.Lsccb:
730	.hword 0x1000			# length, one page
731	.byte 0x00,0x00,0x00
732	.byte 0x80			# variable response bit set
733.Lsccbr:
734	.hword 0x00			# response code
735.Lscpincr1:
736	.hword 0x00
737.Lscpa1:
738	.byte 0x00
739	.fill 89,1,0
740.Lscpa2:
741	.int 0x00
742.Lscpincr2:
743	.quad 0x00
744	.fill 3984,1,0
745	.org 0x12000
746	.global _pend
747_pend:
748
749#ifdef CONFIG_SHARED_KERNEL
750	.org   0x100000
751#endif
752
753#
754# startup-code, running in virtual mode
755#
756        .globl _stext
757_stext:	basr  %r13,0                    # get base
758.LPG2:
759#
760# Setup stack
761#
762	larl  %r15,init_thread_union
763	lg    %r14,__TI_task(%r15)      # cache current in lowcore
764	stg   %r14,__LC_CURRENT
765        aghi  %r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union + THREAD_SIZE
766        stg   %r15,__LC_KERNEL_STACK    # set end of kernel stack
767        aghi  %r15,-160
768        xc    __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15) # clear backchain
769
770# check control registers
771        stctg  %c0,%c15,0(%r15)
772	oi     6(%r15),0x40             # enable sigp emergency signal
773	oi     4(%r15),0x10             # switch on low address proctection
774        lctlg  %c0,%c15,0(%r15)
775
776#
777        lam    0,15,.Laregs-.LPG2(%r13) # load access regs needed by uaccess
778        brasl  %r14,start_kernel        # go to C code
779#
780# We returned from start_kernel ?!? PANIK
781#
782        basr  %r13,0
783	lpswe .Ldw-.(%r13)           # load disabled wait psw
784#
785            .align 8
786.Ldw:       .quad  0x0002000180000000,0x0000000000000000
787.Laregs:    .long  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
788
789