xref: /linux/arch/s390/kernel/head64.S (revision d67b569f5f620c0fb95d5212642746b7ba9d29e4)
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	mvc   0x78(8),.Lrdrnewpsw	       # set up IO interrupt psw
349.Lwaitrdrirq:
350	lpsw  .Lrdrwaitpsw
351.Lrdrint:
352	c     %r1,0xb8			       # compare subchannel number
353	bne   .Lwaitrdrirq
354	la    %r5,.Lirb
355	tsch  0(%r5)
356.Lnoreset:
357	b     .Lnoload
358
359	.align 8
360.Lrdrnewpsw:
361	.long  0x00080000,0x80000000+.Lrdrint
362.Lrdrwaitpsw:
363	.long  0x020a0000,0x80000000+.Lrdrint
364#endif
365
366#
367# everything loaded, go for it
368#
369.Lnoload:
370        l     %r1,.Lstartup
371        br    %r1
372
373.Lstartup: .long startup
374.Lcvtab:.long  _ebcasc                         # ebcdic to ascii table
375.Lreset:.byte  0xc3,0xc8,0xc1,0xd5,0xc7,0xc5,0x40,0xd9,0xc4,0xd9,0x40
376        .byte  0xc1,0xd3,0xd3,0x40,0xd2,0xc5,0xc5,0xd7,0x40,0xd5,0xd6
377        .byte  0xc8,0xd6,0xd3,0xc4             # "change rdr all keep nohold"
378.L_eof: .long  0xc5d6c600       /* C'EOF' */
379.L_hdr: .long  0xc8c4d900       /* C'HDR' */
380#endif  /* CONFIG_IPL */
381
382#
383# SALIPL loader support. Based on a patch by Rob van der Heij.
384# This entry point is called directly from the SALIPL loader and
385# doesn't need a builtin ipl record.
386#
387        .org  0x800
388	.globl start
389start:
390	stm   %r0,%r15,0x07b0		# store registers
391	basr  %r12,%r0
392.base:
393	l     %r11,.parm
394	l     %r8,.cmd			# pointer to command buffer
395
396	ltr   %r9,%r9			# do we have SALIPL parameters?
397	bp    .sk8x8
398
399	mvc   0(64,%r8),0x00b0		# copy saved registers
400	xc    64(240-64,%r8),0(%r8)	# remainder of buffer
401	tr    0(64,%r8),.lowcase
402	b     .gotr
403.sk8x8:
404	mvc   0(240,%r8),0(%r9)		# copy iplparms into buffer
405.gotr:
406	l     %r10,.tbl			# EBCDIC to ASCII table
407	tr    0(240,%r8),0(%r10)
408	stidp __LC_CPUID		# Are we running on VM maybe
409	cli   __LC_CPUID,0xff
410	bnz   .test
411	.long 0x83300060		# diag 3,0,x'0060' - storage size
412	b     .done
413.test:
414	mvc   0x68(8),.pgmnw		# set up pgm check handler
415	l     %r2,.fourmeg
416	lr    %r3,%r2
417	bctr  %r3,%r0			# 4M-1
418.loop:  iske  %r0,%r3
419	ar    %r3,%r2
420.pgmx:
421	sr    %r3,%r2
422	la    %r3,1(%r3)
423.done:
424	l     %r1,.memsize
425	st    %r3,4(%r1)
426	slr   %r0,%r0
427	st    %r0,INITRD_SIZE+4-PARMAREA(%r11)
428	st    %r0,INITRD_START+4-PARMAREA(%r11)
429	j     startup                   # continue with startup
430.tbl:	.long _ebcasc			# translate table
431.cmd:	.long COMMAND_LINE		# address of command line buffer
432.parm:	.long PARMAREA
433.fourmeg: .long 0x00400000      	# 4M
434.pgmnw:	.long 0x00080000,.pgmx
435.memsize: .long memory_size
436.lowcase:
437	.byte 0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07
438	.byte 0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f
439	.byte 0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17
440	.byte 0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f
441	.byte 0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27
442	.byte 0x28,0x29,0x2a,0x2b,0x2c,0x2d,0x2e,0x2f
443	.byte 0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37
444	.byte 0x38,0x39,0x3a,0x3b,0x3c,0x3d,0x3e,0x3f
445	.byte 0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47
446	.byte 0x48,0x49,0x4a,0x4b,0x4c,0x4d,0x4e,0x4f
447	.byte 0x50,0x51,0x52,0x53,0x54,0x55,0x56,0x57
448	.byte 0x58,0x59,0x5a,0x5b,0x5c,0x5d,0x5e,0x5f
449	.byte 0x60,0x61,0x62,0x63,0x64,0x65,0x66,0x67
450	.byte 0x68,0x69,0x6a,0x6b,0x6c,0x6d,0x6e,0x6f
451	.byte 0x70,0x71,0x72,0x73,0x74,0x75,0x76,0x77
452	.byte 0x78,0x79,0x7a,0x7b,0x7c,0x7d,0x7e,0x7f
453
454	.byte 0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87
455	.byte 0x88,0x89,0x8a,0x8b,0x8c,0x8d,0x8e,0x8f
456	.byte 0x90,0x91,0x92,0x93,0x94,0x95,0x96,0x97
457	.byte 0x98,0x99,0x9a,0x9b,0x9c,0x9d,0x9e,0x9f
458	.byte 0xa0,0xa1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7
459	.byte 0xa8,0xa9,0xaa,0xab,0xac,0xad,0xae,0xaf
460	.byte 0xb0,0xb1,0xb2,0xb3,0xb4,0xb5,0xb6,0xb7
461	.byte 0xb8,0xb9,0xba,0xbb,0xbc,0xbd,0xbe,0xbf
462	.byte 0xc0,0x81,0x82,0x83,0x84,0x85,0x86,0x87	# .abcdefg
463	.byte 0x88,0x89,0xca,0xcb,0xcc,0xcd,0xce,0xcf	# hi
464	.byte 0xd0,0x91,0x92,0x93,0x94,0x95,0x96,0x97 	# .jklmnop
465	.byte 0x98,0x99,0xda,0xdb,0xdc,0xdd,0xde,0xdf	# qr
466	.byte 0xe0,0xe1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7	# ..stuvwx
467	.byte 0xa8,0xa9,0xea,0xeb,0xec,0xed,0xee,0xef	# yz
468	.byte 0xf0,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7
469	.byte 0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfe,0xff
470
471#
472# startup-code at 0x10000, running in real mode
473# this is called either by the ipl loader or directly by PSW restart
474# or linload or SALIPL
475#
476        .org  0x10000
477startup:basr  %r13,0                     # get base
478.LPG1:  sll   %r13,1                     # remove high order bit
479        srl   %r13,1
480        lhi   %r1,1                      # mode 1 = esame
481        slr   %r0,%r0                    # set cpuid to zero
482        sigp  %r1,%r0,0x12               # switch to esame mode
483	sam64				 # switch to 64 bit mode
484	lctlg %c0,%c15,.Lctl-.LPG1(%r13) # load control registers
485	larl  %r12,_pstart               # pointer to parameter area
486					 # move IPL device to lowcore
487        mvc   __LC_IPLDEV(4),IPL_DEVICE+4-PARMAREA(%r12)
488
489#
490# clear bss memory
491#
492	larl  %r2,__bss_start           # start of bss segment
493        larl  %r3,_end                  # end of bss segment
494        sgr   %r3,%r2                   # length of bss
495        sgr   %r4,%r4                   #
496        sgr   %r5,%r5                   # set src,length and pad to zero
497        mvcle %r2,%r4,0                 # clear mem
498        jo    .-4                       # branch back, if not finish
499
500	l     %r2,.Lrcp-.LPG1(%r13)	# Read SCP forced command word
501.Lservicecall:
502	stosm .Lpmask-.LPG1(%r13),0x01	# authorize ext interrupts
503
504	stctg %r0,%r0,.Lcr-.LPG1(%r13)	# get cr0
505	la    %r1,0x200			# set bit 22
506	og    %r1,.Lcr-.LPG1(%r13)	# or old cr0 with r1
507	stg   %r1,.Lcr-.LPG1(%r13)
508	lctlg %r0,%r0,.Lcr-.LPG1(%r13)	# load modified cr0
509
510	mvc   __LC_EXT_NEW_PSW(8),.Lpcmsk-.LPG1(%r13) # set postcall psw
511	larl  %r1,.Lsclph
512	stg   %r1,__LC_EXT_NEW_PSW+8	# set handler
513
514	larl  %r4,_pstart		# %r4 is our index for sccb stuff
515	la    %r1,.Lsccb-PARMAREA(%r4)	# our sccb
516	.insn rre,0xb2200000,%r2,%r1	# service call
517	ipm   %r1
518	srl   %r1,28			# get cc code
519	xr    %r3,%r3
520	chi   %r1,3
521	be    .Lfchunk-.LPG1(%r13)	# leave
522	chi   %r1,2
523	be    .Lservicecall-.LPG1(%r13)
524	lpsw  .Lwaitsclp-.LPG1(%r13)
525.Lsclph:
526	lh    %r1,.Lsccbr-PARMAREA(%r4)
527	chi   %r1,0x10			# 0x0010 is the sucess code
528	je    .Lprocsccb		# let's process the sccb
529	chi   %r1,0x1f0
530	bne   .Lfchunk-.LPG1(%r13)	# unhandled error code
531	c     %r2,.Lrcp-.LPG1(%r13)	# Did we try Read SCP forced
532	bne   .Lfchunk-.LPG1(%r13)	# if no, give up
533	l     %r2,.Lrcp2-.LPG1(%r13)	# try with Read SCP
534	b     .Lservicecall-.LPG1(%r13)
535.Lprocsccb:
536	lghi  %r1,0
537	icm   %r1,3,.Lscpincr1-PARMAREA(%r4) # use this one if != 0
538	jnz   .Lscnd
539	lg    %r1,.Lscpincr2-PARMAREA(%r4) # otherwise use this one
540.Lscnd:
541	xr    %r3,%r3			# same logic
542	ic    %r3,.Lscpa1-PARMAREA(%r4)
543	chi   %r3,0x00
544	jne   .Lcompmem
545	l     %r3,.Lscpa2-PARMAREA(%r13)
546.Lcompmem:
547	mlgr  %r2,%r1			# mem in MB on 128-bit
548	l     %r1,.Lonemb-.LPG1(%r13)
549	mlgr  %r2,%r1			# mem size in bytes in %r3
550	b     .Lfchunk-.LPG1(%r13)
551
552.Lpmask:
553	.byte 0
554	.align 8
555.Lcr:
556	.quad 0x00  # place holder for cr0
557.Lwaitsclp:
558	.long 0x020A0000
559	.quad .Lsclph
560.Lrcp:
561	.int 0x00120001 # Read SCP forced code
562.Lrcp2:
563	.int 0x00020001 # Read SCP code
564.Lonemb:
565	.int 0x100000
566
567.Lfchunk:
568					 # set program check new psw mask
569	mvc   __LC_PGM_NEW_PSW(8),.Lpcmsk-.LPG1(%r13)
570
571#
572# find memory chunks.
573#
574	lgr   %r9,%r3			 # end of mem
575	larl  %r1,.Lchkmem               # set program check address
576	stg   %r1,__LC_PGM_NEW_PSW+8
577	la    %r1,1                      # test in increments of 128KB
578	sllg  %r1,%r1,17
579	larl  %r3,memory_chunk
580	slgr  %r4,%r4                    # set start of chunk to zero
581	slgr  %r5,%r5                    # set end of chunk to zero
582	slr  %r6,%r6			 # set access code to zero
583	la    %r10,MEMORY_CHUNKS	 # number of chunks
584.Lloop:
585	tprot 0(%r5),0			 # test protection of first byte
586	ipm   %r7
587	srl   %r7,28
588	clr   %r6,%r7			 # compare cc with last access code
589	je    .Lsame
590	j     .Lchkmem
591.Lsame:
592	algr  %r5,%r1			 # add 128KB to end of chunk
593					 # no need to check here,
594	brc   12,.Lloop			 # this is the same chunk
595.Lchkmem:				 # > 16EB or tprot got a program check
596	clgr  %r4,%r5			 # chunk size > 0?
597	je    .Lchkloop
598	stg   %r4,0(%r3)		 # store start address of chunk
599	lgr   %r0,%r5
600	slgr  %r0,%r4
601	stg   %r0,8(%r3)		 # store size of chunk
602	st    %r6,20(%r3)		 # store type of chunk
603	la    %r3,24(%r3)
604	larl  %r8,memory_size
605	stg   %r5,0(%r8)                 # store memory size
606	ahi   %r10,-1			 # update chunk number
607.Lchkloop:
608	lr    %r6,%r7			 # set access code to last cc
609	# we got an exception or we're starting a new
610	# chunk , we must check if we should
611	# still try to find valid memory (if we detected
612	# the amount of available storage), and if we
613	# have chunks left
614	lghi  %r4,1
615	sllg  %r4,%r4,31
616	clgr  %r5,%r4
617	je    .Lhsaskip
618	xr    %r0, %r0
619	clgr  %r0, %r9			 # did we detect memory?
620	je    .Ldonemem			 # if not, leave
621	chi   %r10, 0			 # do we have chunks left?
622	je    .Ldonemem
623.Lhsaskip:
624	algr  %r5,%r1			 # add 128KB to end of chunk
625	lgr   %r4,%r5			 # potential new chunk
626	clgr  %r5,%r9			 # should we go on?
627	jl    .Lloop
628.Ldonemem:
629
630	larl  %r12,machine_flags
631#
632# find out if we are running under VM
633#
634        stidp  __LC_CPUID               # store cpuid
635	tm     __LC_CPUID,0xff          # running under VM ?
636	bno    0f-.LPG1(%r13)
637        oi     7(%r12),1                # set VM flag
6380:      lh     %r0,__LC_CPUID+4         # get cpu version
639        chi    %r0,0x7490               # running on a P/390 ?
640        bne    1f-.LPG1(%r13)
641        oi     7(%r12),4                # set P/390 flag
6421:
643
644#
645# find out if we have the MVPG instruction
646#
647	la     %r1,0f-.LPG1(%r13)       # set program check address
648	stg    %r1,__LC_PGM_NEW_PSW+8
649	sgr    %r0,%r0
650	lghi   %r1,0
651	lghi   %r2,0
652	mvpg   %r1,%r2                  # test MVPG instruction
653	oi     7(%r12),16               # set MVPG flag
6540:
655
656#
657# find out if the diag 0x44 works in 64 bit mode
658#
659	la     %r1,0f-.LPG1(%r13)	# set program check address
660	stg    %r1,__LC_PGM_NEW_PSW+8
661	mvc    __LC_DIAG44_OPCODE(8),.Lnop-.LPG1(%r13)
662	diag   0,0,0x44			# test diag 0x44
663	oi     7(%r12),32		# set diag44 flag
664	mvc    __LC_DIAG44_OPCODE(8),.Ldiag44-.LPG1(%r13)
6650:
666
667#
668# find out if we have the IDTE instruction
669#
670	la     %r1,0f-.LPG1(%r13)	# set program check address
671	stg    %r1,__LC_PGM_NEW_PSW+8
672	.long	0xb2b10000		# store facility list
673	tm	0xc8,0x08		# check bit for clearing-by-ASCE
674	bno	0f-.LPG1(%r13)
675	lhi	%r1,2094
676	lhi	%r2,0
677	.long	0xb98e2001
678	oi	7(%r12),0x80		# set IDTE flag
6790:
680
681        lpswe .Lentry-.LPG1(13)         # jump to _stext in primary-space,
682                                        # virtual and never return ...
683        .align 16
684.Lentry:.quad  0x0000000180000000,_stext
685.Lctl:  .quad  0x04b50002               # cr0: various things
686        .quad  0                        # cr1: primary space segment table
687        .quad  .Lduct                   # cr2: dispatchable unit control table
688        .quad  0                        # cr3: instruction authorization
689        .quad  0                        # cr4: instruction authorization
690        .quad  0xffffffffffffffff       # cr5: primary-aste origin
691        .quad  0                        # cr6:  I/O interrupts
692        .quad  0                        # cr7:  secondary space segment table
693        .quad  0                        # cr8:  access registers translation
694        .quad  0                        # cr9:  tracing off
695        .quad  0                        # cr10: tracing off
696        .quad  0                        # cr11: tracing off
697        .quad  0                        # cr12: tracing off
698        .quad  0                        # cr13: home space segment table
699        .quad  0xc0000000               # cr14: machine check handling off
700        .quad  0                        # cr15: linkage stack operations
701.Lpcmsk:.quad  0x0000000180000000
702.L4malign:.quad 0xffffffffffc00000
703.Lscan2g:.quad 0x80000000 + 0x20000 - 8 # 2GB + 128K - 8
704.Lnop:	.long  0x07000700
705.Ldiag44:.long 0x83000044
706
707	.org PARMAREA-64
708.Lduct:	.long 0,0,0,0,0,0,0,0
709	.long 0,0,0,0,0,0,0,0
710
711#
712# params at 10400 (setup.h)
713#
714	.org   PARMAREA
715	.global _pstart
716_pstart:
717	.quad  0                        # IPL_DEVICE
718        .quad  RAMDISK_ORIGIN           # INITRD_START
719        .quad  RAMDISK_SIZE             # INITRD_SIZE
720
721        .org   COMMAND_LINE
722    	.byte  "root=/dev/ram0 ro"
723        .byte  0
724	.org   0x11000
725.Lsccb:
726	.hword 0x1000			# length, one page
727	.byte 0x00,0x00,0x00
728	.byte 0x80			# variable response bit set
729.Lsccbr:
730	.hword 0x00			# response code
731.Lscpincr1:
732	.hword 0x00
733.Lscpa1:
734	.byte 0x00
735	.fill 89,1,0
736.Lscpa2:
737	.int 0x00
738.Lscpincr2:
739	.quad 0x00
740	.fill 3984,1,0
741	.org 0x12000
742	.global _pend
743_pend:
744
745#ifdef CONFIG_SHARED_KERNEL
746	.org   0x100000
747#endif
748
749#
750# startup-code, running in virtual mode
751#
752        .globl _stext
753_stext:	basr  %r13,0                    # get base
754.LPG2:
755#
756# Setup stack
757#
758	larl  %r15,init_thread_union
759	lg    %r14,__TI_task(%r15)      # cache current in lowcore
760	stg   %r14,__LC_CURRENT
761        aghi  %r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union + THREAD_SIZE
762        stg   %r15,__LC_KERNEL_STACK    # set end of kernel stack
763        aghi  %r15,-160
764        xc    __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15) # clear backchain
765
766# check control registers
767        stctg  %c0,%c15,0(%r15)
768	oi     6(%r15),0x20             # enable sigp external interrupts
769	oi     4(%r15),0x10             # switch on low address proctection
770        lctlg  %c0,%c15,0(%r15)
771
772#
773        lam    0,15,.Laregs-.LPG2(%r13) # load access regs needed by uaccess
774        brasl  %r14,start_kernel        # go to C code
775#
776# We returned from start_kernel ?!? PANIK
777#
778        basr  %r13,0
779	lpswe .Ldw-.(%r13)           # load disabled wait psw
780#
781            .align 8
782.Ldw:       .quad  0x0002000180000000,0x0000000000000000
783.Laregs:    .long  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
784
785