summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/entry.S
blob: 26c08ee877407745353e257f397a84a29bf580b2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
/* SPDX-License-Identifier: GPL-2.0 */
/*
 *    S390 low-level entry points.
 *
 *    Copyright IBM Corp. 1999, 2012
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
 *		 Hartmut Penner (hp@de.ibm.com),
 *		 Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
 */

#include <linux/export.h>
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/asm-extable.h>
#include <asm/alternative-asm.h>
#include <asm/processor.h>
#include <asm/cache.h>
#include <asm/dwarf.h>
#include <asm/errno.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>
#include <asm/unistd.h>
#include <asm/page.h>
#include <asm/sigp.h>
#include <asm/irq.h>
#include <asm/vx-insn.h>
#include <asm/setup.h>
#include <asm/nmi.h>
#include <asm/nospec-insn.h>

_LPP_OFFSET	= __LC_LPP

	.macro STBEAR address
	ALTERNATIVE "nop", ".insn s,0xb2010000,\address", 193
	.endm

	.macro LBEAR address
	ALTERNATIVE "nop", ".insn s,0xb2000000,\address", 193
	.endm

	.macro LPSWEY address,lpswe
	ALTERNATIVE "b \lpswe; nopr", ".insn siy,0xeb0000000071,\address,0", 193
	.endm

	.macro MBEAR reg
	ALTERNATIVE "brcl 0,0", __stringify(mvc __PT_LAST_BREAK(8,\reg),__LC_LAST_BREAK), 193
	.endm

	.macro	CHECK_STACK savearea
#ifdef CONFIG_CHECK_STACK
	tml	%r15,THREAD_SIZE - CONFIG_STACK_GUARD
	lghi	%r14,\savearea
	jz	stack_overflow
#endif
	.endm

	.macro	CHECK_VMAP_STACK savearea,oklabel
#ifdef CONFIG_VMAP_STACK
	lgr	%r14,%r15
	nill	%r14,0x10000 - THREAD_SIZE
	oill	%r14,STACK_INIT_OFFSET
	clg	%r14,__LC_KERNEL_STACK
	je	\oklabel
	clg	%r14,__LC_ASYNC_STACK
	je	\oklabel
	clg	%r14,__LC_MCCK_STACK
	je	\oklabel
	clg	%r14,__LC_NODAT_STACK
	je	\oklabel
	clg	%r14,__LC_RESTART_STACK
	je	\oklabel
	lghi	%r14,\savearea
	j	stack_overflow
#else
	j	\oklabel
#endif
	.endm

	/*
	 * The TSTMSK macro generates a test-under-mask instruction by
	 * calculating the memory offset for the specified mask value.
	 * Mask value can be any constant.  The macro shifts the mask
	 * value to calculate the memory offset for the test-under-mask
	 * instruction.
	 */
	.macro TSTMSK addr, mask, size=8, bytepos=0
		.if (\bytepos < \size) && (\mask >> 8)
			.if (\mask & 0xff)
				.error "Mask exceeds byte boundary"
			.endif
			TSTMSK \addr, "(\mask >> 8)", \size, "(\bytepos + 1)"
			.exitm
		.endif
		.ifeq \mask
			.error "Mask must not be zero"
		.endif
		off = \size - \bytepos - 1
		tm	off+\addr, \mask
	.endm

	.macro BPOFF
	ALTERNATIVE "nop", ".insn rrf,0xb2e80000,0,0,12,0", 82
	.endm

	.macro BPON
	ALTERNATIVE "nop", ".insn rrf,0xb2e80000,0,0,13,0", 82
	.endm

	.macro BPENTER tif_ptr,tif_mask
	ALTERNATIVE "TSTMSK \tif_ptr,\tif_mask; jz .+8; .insn rrf,0xb2e80000,0,0,13,0", \
		    "j .+12; nop; nop", 82
	.endm

	.macro BPEXIT tif_ptr,tif_mask
	TSTMSK	\tif_ptr,\tif_mask
	ALTERNATIVE "jz .+8;  .insn rrf,0xb2e80000,0,0,12,0", \
		    "jnz .+8; .insn rrf,0xb2e80000,0,0,13,0", 82
	.endm

#if IS_ENABLED(CONFIG_KVM)
	/*
	 * The OUTSIDE macro jumps to the provided label in case the value
	 * in the provided register is outside of the provided range. The
	 * macro is useful for checking whether a PSW stored in a register
	 * pair points inside or outside of a block of instructions.
	 * @reg: register to check
	 * @start: start of the range
	 * @end: end of the range
	 * @outside_label: jump here if @reg is outside of [@start..@end)
	 */
	.macro OUTSIDE reg,start,end,outside_label
	lgr	%r14,\reg
	larl	%r13,\start
	slgr	%r14,%r13
	clgfrl	%r14,.Lrange_size\@
	jhe	\outside_label
	.section .rodata, "a"
	.balign 4
.Lrange_size\@:
	.long	\end - \start
	.previous
	.endm

	.macro SIEEXIT
	lg	%r9,__SF_SIE_CONTROL(%r15)	# get control block pointer
	ni	__SIE_PROG0C+3(%r9),0xfe	# no longer in SIE
	lctlg	%c1,%c1,__LC_KERNEL_ASCE	# load primary asce
	larl	%r9,sie_exit			# skip forward to sie_exit
	.endm
#endif

	.macro STACKLEAK_ERASE
#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
	brasl	%r14,stackleak_erase_on_task_stack
#endif
	.endm

	GEN_BR_THUNK %r14

	.section .kprobes.text, "ax"
.Ldummy:
	/*
	 * The following nop exists only in order to avoid that the next
	 * symbol starts at the beginning of the kprobes text section.
	 * In that case there would be several symbols at the same address.
	 * E.g. objdump would take an arbitrary symbol when disassembling
	 * the code.
	 * With the added nop in between this cannot happen.
	 */
	nop	0

/*
 * Scheduler resume function, called by switch_to
 *  gpr2 = (task_struct *) prev
 *  gpr3 = (task_struct *) next
 * Returns:
 *  gpr2 = prev
 */
SYM_FUNC_START(__switch_to)
	stmg	%r6,%r15,__SF_GPRS(%r15)	# store gprs of prev task
	lghi	%r4,__TASK_stack
	lghi	%r1,__TASK_thread
	llill	%r5,STACK_INIT_OFFSET
	stg	%r15,__THREAD_ksp(%r1,%r2)	# store kernel stack of prev
	lg	%r15,0(%r4,%r3)			# start of kernel stack of next
	agr	%r15,%r5			# end of kernel stack of next
	stg	%r3,__LC_CURRENT		# store task struct of next
	stg	%r15,__LC_KERNEL_STACK		# store end of kernel stack
	lg	%r15,__THREAD_ksp(%r1,%r3)	# load kernel stack of next
	aghi	%r3,__TASK_pid
	mvc	__LC_CURRENT_PID(4,%r0),0(%r3)	# store pid of next
	lmg	%r6,%r15,__SF_GPRS(%r15)	# load gprs of next task
	ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40
	BR_EX	%r14
SYM_FUNC_END(__switch_to)

#if IS_ENABLED(CONFIG_KVM)
/*
 * __sie64a calling convention:
 * %r2 pointer to sie control block phys
 * %r3 pointer to sie control block virt
 * %r4 guest register save area
 */
SYM_FUNC_START(__sie64a)
	stmg	%r6,%r14,__SF_GPRS(%r15)	# save kernel registers
	lg	%r12,__LC_CURRENT
	stg	%r2,__SF_SIE_CONTROL_PHYS(%r15)	# save sie block physical..
	stg	%r3,__SF_SIE_CONTROL(%r15)	# ...and virtual addresses
	stg	%r4,__SF_SIE_SAVEAREA(%r15)	# save guest register save area
	xc	__SF_SIE_REASON(8,%r15),__SF_SIE_REASON(%r15) # reason code = 0
	mvc	__SF_SIE_FLAGS(8,%r15),__TI_flags(%r12) # copy thread flags
	lmg	%r0,%r13,0(%r4)			# load guest gprs 0-13
	lg	%r14,__LC_GMAP			# get gmap pointer
	ltgr	%r14,%r14
	jz	.Lsie_gmap
	lctlg	%c1,%c1,__GMAP_ASCE(%r14)	# load primary asce
.Lsie_gmap:
	lg	%r14,__SF_SIE_CONTROL(%r15)	# get control block pointer
	oi	__SIE_PROG0C+3(%r14),1		# we are going into SIE now
	tm	__SIE_PROG20+3(%r14),3		# last exit...
	jnz	.Lsie_skip
	TSTMSK	__LC_CPU_FLAGS,_CIF_FPU
	jo	.Lsie_skip			# exit if fp/vx regs changed
	lg	%r14,__SF_SIE_CONTROL_PHYS(%r15)	# get sie block phys addr
	BPEXIT	__SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
.Lsie_entry:
	sie	0(%r14)
# Let the next instruction be NOP to avoid triggering a machine check
# and handling it in a guest as result of the instruction execution.
	nopr	7
.Lsie_leave:
	BPOFF
	BPENTER	__SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
.Lsie_skip:
	lg	%r14,__SF_SIE_CONTROL(%r15)	# get control block pointer
	ni	__SIE_PROG0C+3(%r14),0xfe	# no longer in SIE
	lctlg	%c1,%c1,__LC_KERNEL_ASCE	# load primary asce
.Lsie_done:
# some program checks are suppressing. C code (e.g. do_protection_exception)
# will rewind the PSW by the ILC, which is often 4 bytes in case of SIE. There
# are some corner cases (e.g. runtime instrumentation) where ILC is unpredictable.
# Other instructions between __sie64a and .Lsie_done should not cause program
# interrupts. So lets use 3 nops as a landing pad for all possible rewinds.
.Lrewind_pad6:
	nopr	7
.Lrewind_pad4:
	nopr	7
.Lrewind_pad2:
	nopr	7
SYM_INNER_LABEL(sie_exit, SYM_L_GLOBAL)
	lg	%r14,__SF_SIE_SAVEAREA(%r15)	# load guest register save area
	stmg	%r0,%r13,0(%r14)		# save guest gprs 0-13
	xgr	%r0,%r0				# clear guest registers to
	xgr	%r1,%r1				# prevent speculative use
	xgr	%r3,%r3
	xgr	%r4,%r4
	xgr	%r5,%r5
	lmg	%r6,%r14,__SF_GPRS(%r15)	# restore kernel registers
	lg	%r2,__SF_SIE_REASON(%r15)	# return exit reason code
	BR_EX	%r14
.Lsie_fault:
	lghi	%r14,-EFAULT
	stg	%r14,__SF_SIE_REASON(%r15)	# set exit reason code
	j	sie_exit

	EX_TABLE(.Lrewind_pad6,.Lsie_fault)
	EX_TABLE(.Lrewind_pad4,.Lsie_fault)
	EX_TABLE(.Lrewind_pad2,.Lsie_fault)
	EX_TABLE(sie_exit,.Lsie_fault)
SYM_FUNC_END(__sie64a)
EXPORT_SYMBOL(__sie64a)
EXPORT_SYMBOL(sie_exit)
#endif

/*
 * SVC interrupt handler routine. System calls are synchronous events and
 * are entered with interrupts disabled.
 */

SYM_CODE_START(system_call)
	stpt	__LC_SYS_ENTER_TIMER
	stmg	%r8,%r15,__LC_SAVE_AREA_SYNC
	BPOFF
	lghi	%r14,0
.Lsysc_per:
	STBEAR	__LC_LAST_BREAK
	lctlg	%c1,%c1,__LC_KERNEL_ASCE
	lg	%r15,__LC_KERNEL_STACK
	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
	stmg	%r0,%r7,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
	# clear user controlled register to prevent speculative use
	xgr	%r0,%r0
	xgr	%r1,%r1
	xgr	%r4,%r4
	xgr	%r5,%r5
	xgr	%r6,%r6
	xgr	%r7,%r7
	xgr	%r8,%r8
	xgr	%r9,%r9
	xgr	%r10,%r10
	xgr	%r11,%r11
	la	%r2,STACK_FRAME_OVERHEAD(%r15)	# pointer to pt_regs
	mvc	__PT_R8(64,%r2),__LC_SAVE_AREA_SYNC
	MBEAR	%r2
	lgr	%r3,%r14
	brasl	%r14,__do_syscall
	STACKLEAK_ERASE
	lctlg	%c1,%c1,__LC_USER_ASCE
	mvc	__LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
	BPON
	LBEAR	STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
	lmg	%r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
	stpt	__LC_EXIT_TIMER
	LPSWEY	__LC_RETURN_PSW,__LC_RETURN_LPSWE
SYM_CODE_END(system_call)

#
# a new process exits the kernel with ret_from_fork
#
SYM_CODE_START(ret_from_fork)
	lgr	%r3,%r11
	brasl	%r14,__ret_from_fork
	STACKLEAK_ERASE
	lctlg	%c1,%c1,__LC_USER_ASCE
	mvc	__LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
	BPON
	LBEAR	STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
	lmg	%r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
	stpt	__LC_EXIT_TIMER
	LPSWEY	__LC_RETURN_PSW,__LC_RETURN_LPSWE
SYM_CODE_END(ret_from_fork)

/*
 * Program check handler routine
 */

SYM_CODE_START(pgm_check_handler)
	stpt	__LC_SYS_ENTER_TIMER
	BPOFF
	stmg	%r8,%r15,__LC_SAVE_AREA_SYNC
	lghi	%r10,0
	lmg	%r8,%r9,__LC_PGM_OLD_PSW
	tmhh	%r8,0x0001		# coming from user space?
	jno	.Lpgm_skip_asce
	lctlg	%c1,%c1,__LC_KERNEL_ASCE
	j	3f			# -> fault in user space
.Lpgm_skip_asce:
#if IS_ENABLED(CONFIG_KVM)
	# cleanup critical section for program checks in __sie64a
	OUTSIDE	%r9,.Lsie_gmap,.Lsie_done,1f
	BPENTER	__SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
	SIEEXIT
	lghi	%r10,_PIF_GUEST_FAULT
#endif
1:	tmhh	%r8,0x4000		# PER bit set in old PSW ?
	jnz	2f			# -> enabled, can't be a double fault
	tm	__LC_PGM_ILC+3,0x80	# check for per exception
	jnz	.Lpgm_svcper		# -> single stepped svc
2:	CHECK_STACK __LC_SAVE_AREA_SYNC
	aghi	%r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
	# CHECK_VMAP_STACK branches to stack_overflow or 4f
	CHECK_VMAP_STACK __LC_SAVE_AREA_SYNC,4f
3:	lg	%r15,__LC_KERNEL_STACK
4:	la	%r11,STACK_FRAME_OVERHEAD(%r15)
	stg	%r10,__PT_FLAGS(%r11)
	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
	stmg	%r0,%r7,__PT_R0(%r11)
	mvc	__PT_R8(64,%r11),__LC_SAVE_AREA_SYNC
	mvc	__PT_LAST_BREAK(8,%r11),__LC_PGM_LAST_BREAK
	stmg	%r8,%r9,__PT_PSW(%r11)

	# clear user controlled registers to prevent speculative use
	xgr	%r0,%r0
	xgr	%r1,%r1
	xgr	%r3,%r3
	xgr	%r4,%r4
	xgr	%r5,%r5
	xgr	%r6,%r6
	xgr	%r7,%r7
	lgr	%r2,%r11
	brasl	%r14,__do_pgm_check
	tmhh	%r8,0x0001		# returning to user space?
	jno	.Lpgm_exit_kernel
	STACKLEAK_ERASE
	lctlg	%c1,%c1,__LC_USER_ASCE
	BPON
	stpt	__LC_EXIT_TIMER
.Lpgm_exit_kernel:
	mvc	__LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
	LBEAR	STACK_FRAME_OVERHEAD+__PT_LAST_BREAK(%r15)
	lmg	%r0,%r15,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
	LPSWEY	__LC_RETURN_PSW,__LC_RETURN_LPSWE

#
# single stepped system call
#
.Lpgm_svcper:
	mvc	__LC_RETURN_PSW(8),__LC_SVC_NEW_PSW
	larl	%r14,.Lsysc_per
	stg	%r14,__LC_RETURN_PSW+8
	lghi	%r14,1
	LBEAR	__LC_PGM_LAST_BREAK
	LPSWEY	__LC_RETURN_PSW,__LC_RETURN_LPSWE # branch to .Lsysc_per
SYM_CODE_END(pgm_check_handler)

/*
 * Interrupt handler macro used for external and IO interrupts.
 */
.macro INT_HANDLER name,lc_old_psw,handler
SYM_CODE_START(\name)
	stckf	__LC_INT_CLOCK
	stpt	__LC_SYS_ENTER_TIMER
	STBEAR	__LC_LAST_BREAK
	BPOFF
	stmg	%r8,%r15,__LC_SAVE_AREA_ASYNC
	lmg	%r8,%r9,\lc_old_psw
	tmhh	%r8,0x0001			# interrupting from user ?
	jnz	1f
#if IS_ENABLED(CONFIG_KVM)
	OUTSIDE	%r9,.Lsie_gmap,.Lsie_done,0f
	BPENTER	__SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
	SIEEXIT
#endif
0:	CHECK_STACK __LC_SAVE_AREA_ASYNC
	aghi	%r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
	j	2f
1:	lctlg	%c1,%c1,__LC_KERNEL_ASCE
	lg	%r15,__LC_KERNEL_STACK
2:	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
	la	%r11,STACK_FRAME_OVERHEAD(%r15)
	stmg	%r0,%r7,__PT_R0(%r11)
	# clear user controlled registers to prevent speculative use
	xgr	%r0,%r0
	xgr	%r1,%r1
	xgr	%r3,%r3
	xgr	%r4,%r4
	xgr	%r5,%r5
	xgr	%r6,%r6
	xgr	%r7,%r7
	xgr	%r10,%r10
	xc	__PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
	mvc	__PT_R8(64,%r11),__LC_SAVE_AREA_ASYNC
	MBEAR	%r11
	stmg	%r8,%r9,__PT_PSW(%r11)
	lgr	%r2,%r11		# pass pointer to pt_regs
	brasl	%r14,\handler
	mvc	__LC_RETURN_PSW(16),__PT_PSW(%r11)
	tmhh	%r8,0x0001		# returning to user ?
	jno	2f
	STACKLEAK_ERASE
	lctlg	%c1,%c1,__LC_USER_ASCE
	BPON
	stpt	__LC_EXIT_TIMER
2:	LBEAR	__PT_LAST_BREAK(%r11)
	lmg	%r0,%r15,__PT_R0(%r11)
	LPSWEY	__LC_RETURN_PSW,__LC_RETURN_LPSWE
SYM_CODE_END(\name)
.endm

INT_HANDLER ext_int_handler,__LC_EXT_OLD_PSW,do_ext_irq
INT_HANDLER io_int_handler,__LC_IO_OLD_PSW,do_io_irq

/*
 * Load idle PSW.
 */
SYM_FUNC_START(psw_idle)
	stg	%r14,(__SF_GPRS+8*8)(%r15)
	stg	%r3,__SF_EMPTY(%r15)
	larl	%r1,psw_idle_exit
	stg	%r1,__SF_EMPTY+8(%r15)
	larl	%r1,smp_cpu_mtid
	llgf	%r1,0(%r1)
	ltgr	%r1,%r1
	jz	.Lpsw_idle_stcctm
	.insn	rsy,0xeb0000000017,%r1,5,__MT_CYCLES_ENTER(%r2)
.Lpsw_idle_stcctm:
	oi	__LC_CPU_FLAGS+7,_CIF_ENABLED_WAIT
	BPON
	stckf	__CLOCK_IDLE_ENTER(%r2)
	stpt	__TIMER_IDLE_ENTER(%r2)
	lpswe	__SF_EMPTY(%r15)
SYM_INNER_LABEL(psw_idle_exit, SYM_L_GLOBAL)
	BR_EX	%r14
SYM_FUNC_END(psw_idle)

/*
 * Machine check handler routines
 */
SYM_CODE_START(mcck_int_handler)
	BPOFF
	la	%r1,4095		# validate r1
	spt	__LC_CPU_TIMER_SAVE_AREA-4095(%r1)	# validate cpu timer
	LBEAR	__LC_LAST_BREAK_SAVE_AREA-4095(%r1)		# validate bear
	lmg	%r0,%r15,__LC_GPREGS_SAVE_AREA		# validate gprs
	lmg	%r8,%r9,__LC_MCK_OLD_PSW
	TSTMSK	__LC_MCCK_CODE,MCCK_CODE_SYSTEM_DAMAGE
	jo	.Lmcck_panic		# yes -> rest of mcck code invalid
	TSTMSK	__LC_MCCK_CODE,MCCK_CODE_CR_VALID
	jno	.Lmcck_panic		# control registers invalid -> panic
	lctlg	%c0,%c15,__LC_CREGS_SAVE_AREA		# validate ctl regs
	ptlb
	lghi	%r14,__LC_CPU_TIMER_SAVE_AREA
	mvc	__LC_MCCK_ENTER_TIMER(8),0(%r14)
	TSTMSK	__LC_MCCK_CODE,MCCK_CODE_CPU_TIMER_VALID
	jo	3f
	la	%r14,__LC_SYS_ENTER_TIMER
	clc	0(8,%r14),__LC_EXIT_TIMER
	jl	1f
	la	%r14,__LC_EXIT_TIMER
1:	clc	0(8,%r14),__LC_LAST_UPDATE_TIMER
	jl	2f
	la	%r14,__LC_LAST_UPDATE_TIMER
2:	spt	0(%r14)
	mvc	__LC_MCCK_ENTER_TIMER(8),0(%r14)
3:	TSTMSK	__LC_MCCK_CODE,MCCK_CODE_PSW_MWP_VALID
	jno	.Lmcck_panic
	tmhh	%r8,0x0001		# interrupting from user ?
	jnz	.Lmcck_user
	TSTMSK	__LC_MCCK_CODE,MCCK_CODE_PSW_IA_VALID
	jno	.Lmcck_panic
#if IS_ENABLED(CONFIG_KVM)
	OUTSIDE	%r9,.Lsie_gmap,.Lsie_done,.Lmcck_user
	OUTSIDE	%r9,.Lsie_entry,.Lsie_leave,4f
	oi	__LC_CPU_FLAGS+7, _CIF_MCCK_GUEST
4:	BPENTER	__SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
	SIEEXIT
#endif
.Lmcck_user:
	lg	%r15,__LC_MCCK_STACK
	la	%r11,STACK_FRAME_OVERHEAD(%r15)
	stctg	%c1,%c1,__PT_CR1(%r11)
	lctlg	%c1,%c1,__LC_KERNEL_ASCE
	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
	lghi	%r14,__LC_GPREGS_SAVE_AREA+64
	stmg	%r0,%r7,__PT_R0(%r11)
	# clear user controlled registers to prevent speculative use
	xgr	%r0,%r0
	xgr	%r1,%r1
	xgr	%r3,%r3
	xgr	%r4,%r4
	xgr	%r5,%r5
	xgr	%r6,%r6
	xgr	%r7,%r7
	xgr	%r10,%r10
	mvc	__PT_R8(64,%r11),0(%r14)
	stmg	%r8,%r9,__PT_PSW(%r11)
	xc	__PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
	lgr	%r2,%r11		# pass pointer to pt_regs
	brasl	%r14,s390_do_machine_check
	lctlg	%c1,%c1,__PT_CR1(%r11)
	lmg	%r0,%r10,__PT_R0(%r11)
	mvc	__LC_RETURN_MCCK_PSW(16),__PT_PSW(%r11) # move return PSW
	tm	__LC_RETURN_MCCK_PSW+1,0x01 # returning to user ?
	jno	0f
	BPON
	stpt	__LC_EXIT_TIMER
0:	ALTERNATIVE "nop", __stringify(lghi %r12,__LC_LAST_BREAK_SAVE_AREA),193
	LBEAR	0(%r12)
	lmg	%r11,%r15,__PT_R11(%r11)
	LPSWEY	__LC_RETURN_MCCK_PSW,__LC_RETURN_MCCK_LPSWE

.Lmcck_panic:
	/*
	 * Iterate over all possible CPU addresses in the range 0..0xffff
	 * and stop each CPU using signal processor. Use compare and swap
	 * to allow just one CPU-stopper and prevent concurrent CPUs from
	 * stopping each other while leaving the others running.
	 */
	lhi	%r5,0
	lhi	%r6,1
	larl	%r7,stop_lock
	cs	%r5,%r6,0(%r7)		# single CPU-stopper only
	jnz	4f
	larl	%r7,this_cpu
	stap	0(%r7)			# this CPU address
	lh	%r4,0(%r7)
	nilh	%r4,0
	lhi	%r0,1
	sll	%r0,16			# CPU counter
	lhi	%r3,0			# next CPU address
0:	cr	%r3,%r4
	je	2f
1:	sigp	%r1,%r3,SIGP_STOP	# stop next CPU
	brc	SIGP_CC_BUSY,1b
2:	ahi	%r3,1
	brct	%r0,0b
3:	sigp	%r1,%r4,SIGP_STOP	# stop this CPU
	brc	SIGP_CC_BUSY,3b
4:	j	4b
SYM_CODE_END(mcck_int_handler)

SYM_CODE_START(restart_int_handler)
	ALTERNATIVE "nop", "lpp _LPP_OFFSET", 40
	stg	%r15,__LC_SAVE_AREA_RESTART
	TSTMSK	__LC_RESTART_FLAGS,RESTART_FLAG_CTLREGS,4
	jz	0f
	lctlg	%c0,%c15,__LC_CREGS_SAVE_AREA
0:	larl	%r15,daton_psw
	lpswe	0(%r15)				# turn dat on, keep irqs off
.Ldaton:
	lg	%r15,__LC_RESTART_STACK
	xc	STACK_FRAME_OVERHEAD(__PT_SIZE,%r15),STACK_FRAME_OVERHEAD(%r15)
	stmg	%r0,%r14,STACK_FRAME_OVERHEAD+__PT_R0(%r15)
	mvc	STACK_FRAME_OVERHEAD+__PT_R15(8,%r15),__LC_SAVE_AREA_RESTART
	mvc	STACK_FRAME_OVERHEAD+__PT_PSW(16,%r15),__LC_RST_OLD_PSW
	xc	0(STACK_FRAME_OVERHEAD,%r15),0(%r15)
	lg	%r1,__LC_RESTART_FN		# load fn, parm & source cpu
	lg	%r2,__LC_RESTART_DATA
	lgf	%r3,__LC_RESTART_SOURCE
	ltgr	%r3,%r3				# test source cpu address
	jm	1f				# negative -> skip source stop
0:	sigp	%r4,%r3,SIGP_SENSE		# sigp sense to source cpu
	brc	10,0b				# wait for status stored
1:	basr	%r14,%r1			# call function
	stap	__SF_EMPTY(%r15)		# store cpu address
	llgh	%r3,__SF_EMPTY(%r15)
2:	sigp	%r4,%r3,SIGP_STOP		# sigp stop to current cpu
	brc	2,2b
3:	j	3b
SYM_CODE_END(restart_int_handler)

	.section .kprobes.text, "ax"

#if defined(CONFIG_CHECK_STACK) || defined(CONFIG_VMAP_STACK)
/*
 * The synchronous or the asynchronous stack overflowed. We are dead.
 * No need to properly save the registers, we are going to panic anyway.
 * Setup a pt_regs so that show_trace can provide a good call trace.
 */
SYM_CODE_START(stack_overflow)
	lg	%r15,__LC_NODAT_STACK	# change to panic stack
	la	%r11,STACK_FRAME_OVERHEAD(%r15)
	stmg	%r0,%r7,__PT_R0(%r11)
	stmg	%r8,%r9,__PT_PSW(%r11)
	mvc	__PT_R8(64,%r11),0(%r14)
	stg	%r10,__PT_ORIG_GPR2(%r11) # store last break to orig_gpr2
	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
	lgr	%r2,%r11		# pass pointer to pt_regs
	jg	kernel_stack_overflow
SYM_CODE_END(stack_overflow)
#endif

	.section .data, "aw"
	.balign	4
SYM_DATA_LOCAL(stop_lock,	.long 0)
SYM_DATA_LOCAL(this_cpu,	.short 0)
	.balign	8
SYM_DATA_START_LOCAL(daton_psw)
	.quad	PSW_KERNEL_BITS
	.quad	.Ldaton
SYM_DATA_END(daton_psw)

	.section .rodata, "a"
	.balign	8
#define SYSCALL(esame,emu)	.quad __s390x_ ## esame
SYM_DATA_START(sys_call_table)
#include "asm/syscall_table.h"
SYM_DATA_END(sys_call_table)
#undef SYSCALL

#ifdef CONFIG_COMPAT

#define SYSCALL(esame,emu)	.quad __s390_ ## emu
SYM_DATA_START(sys_call_table_emu)
#include "asm/syscall_table.h"
SYM_DATA_END(sys_call_table_emu)
#undef SYSCALL
#endif