aboutsummaryrefslogtreecommitdiff
path: root/arch/cris/arch-v10/kernel/entry.S
blob: 1bc44f481c345044af7ff5cbd7b5608ca0b7575f (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
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
/* $Id: entry.S,v 1.23 2004/10/19 13:07:37 starvik Exp $
 *
 *  linux/arch/cris/entry.S
 *
 *  Copyright (C) 2000, 2001, 2002 Axis Communications AB
 *
 *  Authors:	Bjorn Wesen (bjornw@axis.com)
 *
 *  $Log: entry.S,v $
 *  Revision 1.23  2004/10/19 13:07:37  starvik
 *  Merge of Linux 2.6.9
 *
 *  Revision 1.22  2004/06/21 10:29:55  starvik
 *  Merge of Linux 2.6.7
 *
 *  Revision 1.21  2004/06/09 05:30:27  starvik
 *  Clean up multiple interrupt handling.
 *    Prevent interrupts from interrupting each other.
 *    Handle all active interrupts.
 *
 *  Revision 1.20  2004/06/08 08:55:32  starvik
 *  Removed unused code
 *
 *  Revision 1.19  2004/06/04 11:56:15  starvik
 *  Implemented page table lookup for refills in assembler for improved performance.
 *
 *  Revision 1.18  2004/05/11 12:28:25  starvik
 *  Merge of Linux 2.6.6
 *
 *  Revision 1.17  2003/09/11 07:29:49  starvik
 *  Merge of Linux 2.6.0-test5
 *
 *  Revision 1.16  2003/07/04 08:27:41  starvik
 *  Merge of Linux 2.5.74
 *
 *  Revision 1.15  2003/04/09 07:32:55  starvik
 *  resume should return task_struct, not thread_info
 *
 *  Revision 1.14  2003/04/09 05:20:44  starvik
 *  Merge of Linux 2.5.67
 *
 *  Revision 1.13  2002/12/11 15:42:02  starvik
 *  Extracted v10 (ETRAX 100LX) specific stuff from arch/cris/kernel/*.c
 *
 *  Revision 1.12  2002/12/10 09:00:10  starvik
 *  Merge of Linux 2.5.51
 *
 *  Revision 1.11  2002/12/05 07:53:10  starvik
 *  Corrected constants used with btstq
 *
 *  Revision 1.10  2002/11/27 08:45:10  starvik
 *  pid is in task_struct, not thread_info
 *
 *  Revision 1.9  2002/11/26 09:52:05  starvik
 *  Added preemptive kernel scheduling (if CONFIG_PREEMPT)
 *
 *  Revision 1.8  2002/11/20 11:56:11  starvik
 *  Merge of Linux 2.5.48
 *
 *  Revision 1.7  2002/11/18 13:02:42  starvik
 *  Added fourth parameter to do_notify_resume
 *  Minor cleanup
 *
 *  Revision 1.6  2002/11/11 10:37:50  starvik
 *  Use new asm-offset defines
 *  Modified for new location of current->work etc
 *  Removed SYMBOL_NAME from syscalls
 *  Added some new syscalls
 *
 *  Revision 1.5  2002/11/05 06:45:11  starvik
 *  Merge of Linux 2.5.45
 *
 *  Revision 1.4  2002/02/05 15:41:31  bjornw
 *  Rewritten to conform better to current 2.5 code (similar to arch/i386)
 *
 *  Revision 1.3  2002/01/21 15:22:20  bjornw
 *  NICE_DOGGY fix from 2.4 arch/cris
 *
 *  Revision 1.37  2001/12/07 17:03:55  bjornw
 *  Call a c-hook called watchdog_bite_hook instead of show_registers directly
 *
 *  Revision 1.36  2001/11/22 13:36:36  bjornw
 *  * In ret_from_intr, check regs->dccr for usermode reentrance instead of
 *    DCCR explicitely (because the latter might not reflect current reality)
 *  * In mmu_bus_fault, set $r9 _after_ calling the C-code instead of before
 *    since $r9 is call-clobbered and is potentially needed afterwards
 *
 *  Revision 1.35  2001/10/30 17:10:15  bjornw
 *  Add some syscalls
 *
 *  Revision 1.34  2001/10/01 14:45:03  bjornw
 *  Removed underscores and added register prefixes
 *
 *  Revision 1.33  2001/08/21 13:48:01  jonashg
 *  Added fix by HP to avoid oops when doing a hard_reset_now.
 *
 *  Revision 1.32  2001/08/14 04:32:02  hp
 *  In _resume, add comment why R9 is saved; don't sound like it's call-saved.
 *
 *  Revision 1.31  2001/07/25 16:07:42  bjornw
 *  softirq_active/mask -> softirq_pending only
 *
 *  Revision 1.30  2001/07/05 01:03:32  hp
 *  - include asm/errno.h to get ENOSYS.
 *  - Use ENOSYS, not local constant LENOSYS; tweak comments.
 *  - Explain why .include, not #include is used.
 *  - Make oops-register-dump if watchdog bits and it's not expected.
 *  - Don't jsr, use jump _hard_reset_now, and skip spurious nop.
 *  - Use correct section attribute for section .rodata.
 *  - Adjust sys_ni_syscall fill number.
 *
 *  Revision 1.29  2001/06/25 14:07:00  hp
 *  	Fix review comment.
 *  	* head.S: Use IO_STATE, IO_FIELD and IO_MASK constructs instead of
 *  	magic numbers.  Add comment that -traditional must not be used.
 *  	* entry.S (SYMBOL_NAME): Change redefinition to use ## concatenation.
 *  	Correct and update comment.
 *  	* Makefile (.S.o): Don't use -traditional.  Add comment why the
 *  	toplevel rule can't be used (now that there's a reason).
 *
 *  Revision 1.28  2001/06/21 02:00:40  hp
 *  	* entry.S: Include asm/unistd.h.
 *  	(_sys_call_table): Use section .rodata, not .data.
 *  	(_kernel_thread): Move from...
 *  	* process.c: ... here.
 *  	* entryoffsets.c (VAL): Break out from...
 *  	(OF): Use VAL.
 *  	(LCLONE_VM): New asmified value from CLONE_VM.
 *
 *  Revision 1.27  2001/05/29 11:25:27  markusl
 *  In case of "spurious_interrupt", do hard_reset instead of hanging system in a loop...
 *
 *  Revision 1.26  2001/05/15 15:46:03  bjornw
 *  Include config.h now that we use some CONFIG_ options
 *
 *  Revision 1.25  2001/05/15 05:38:47  hp
 *  Tweaked code in _ret_from_sys_call
 *
 *  Revision 1.24  2001/05/15 05:27:49  hp
 *  Save r9 in r1 over function call rather than on stack.
 *
 *  Revision 1.23  2001/05/15 05:10:00  hp
 *  Generate entry.S structure offsets from C
 *
 *  Revision 1.22  2001/04/17 13:58:39  orjanf
 *  * Renamed CONFIG_KGDB to CONFIG_ETRAX_KGDB.
 *
 *  Revision 1.21  2001/04/17 11:33:29  orjanf
 *  Updated according to review:
 *  * Included asm/sv_addr_ag.h to get macro for internal register.
 *  * Corrected comment regarding system call argument passing.
 *  * Removed comment about instruction being in a delay slot.
 *  * Added comment about SYMBOL_NAME macro.
 *
 *  Revision 1.20  2001/04/12 08:51:07  hp
 *  - Add entry for sys_fcntl64.  In fact copy last piece from i386 including ...
 *  - .rept to fill table to safe state with sys_ni_syscall.
 *
 *  Revision 1.19  2001/04/04 09:43:32  orjanf
 *  * Moved do_sigtrap from traps.c to entry.S.
 *  * LTASK_PID need not be global anymore.
 *
 *  Revision 1.18  2001/03/26 09:25:02  markusl
 *  Updated after review, should now handle USB interrupts correctly.
 *
 *  Revision 1.17  2001/03/21 16:12:55  bjornw
 *  * Always make room for the cpu status record in the frame, in order to
 *    use the same framelength and layout for both mmu busfaults and normal
 *    irqs. No need to check for the explicit CRIS_FRAME_FIXUP type anymore.
 *  * Fixed bug with using addq for popping the stack in the epilogue - it
 *    destroyed the flag register. Use instructions that don't affect the
 *    flag register instead.
 *  * Removed write to R_PORT_PA_DATA during spurious_interrupt
 *
 *  Revision 1.16  2001/03/20 19:43:02  bjornw
 *  * Get rid of esp0 setting
 *  * Give a 7th argument to a systemcall - the stackframe
 *
 *  Revision 1.15  2001/03/05 13:14:30  bjornw
 *  Spelling fix
 *
 *  Revision 1.14  2001/02/23 08:36:36  perf
 *  New ABI; syscallnr=r9, arg5=mof, arg6=srp.
 *  Corrected tracesys call check.
 *
 *  Revision 1.13  2001/02/15 08:40:55  perf
 *  H-P by way of perf;
 *  - (_system_call): Don't read system call function address into r1.
 *  - (RBFExit): There is no such thing as a null pop.  Adjust sp by addq.
 *  - (_system_call): Don't use r10 and don't save and restore it.
 *  - (THREAD_ESP0): New constant.
 *  - (_system_call): Inline set_esp0.
 *
 *  Revision 1.12  2001/01/31 17:56:25  orjanf
 *  Added definition of LTASK_PID and made it global.
 *
 *  Revision 1.11  2001/01/10 21:13:29  bjornw
 *  SYMBOL_NAME is defined incorrectly for the compiler options we currently use
 *
 *  Revision 1.10  2000/12/18 23:47:56  bjornw
 *  * Added syscall trace support (ptrace), completely untested of course
 *  * Removed redundant check for NULL entries in syscall_table
 *
 *  Revision 1.9  2000/11/21 16:40:51  bjornw
 *  * New frame type used when an SBFS frame needs to be popped without
 *    actually restarting the instruction
 *  * Enable interrupts in signal_return (they did so in x86, I hope it's a good
 *    idea)
 *
 *  Revision 1.8  2000/11/17 16:53:35  bjornw
 *  Added detection of frame-type in Rexit, so that mmu_bus_fault can
 *  use ret_from_intr in the return-path to check for signals (like SEGV)
 *  and other foul things that might have occurred during the fault.
 *
 *  Revision 1.7  2000/10/06 15:04:28  bjornw
 *  Include mof in register savings
 *
 *  Revision 1.6  2000/09/12 16:02:44  bjornw
 *  Linux-2.4.0-test7 derived updates
 *
 *  Revision 1.5  2000/08/17 15:35:15  bjornw
 *  2.4.0-test6 changed local_irq_count and friends API
 *
 *  Revision 1.4  2000/08/02 13:59:30  bjornw
 *  Removed olduname and uname from the syscall list
 *
 *  Revision 1.3  2000/07/31 13:32:58  bjornw
 *  * Export ret_from_intr
 *  * _resume updated (prev/last tjohejsan)
 *  * timer_interrupt obsolete
 *  * SIGSEGV detection in mmu_bus_fault temporarily disabled
 *
 *
 */

/*
 * entry.S contains the system-call and fault low-level handling routines.
 *
 * NOTE: This code handles signal-recognition, which happens every time
 * after a timer-interrupt and after each system call.
 *
 * Stack layout in 'ret_from_system_call':
 * 	ptrace needs to have all regs on the stack.
 *	if the order here is changed, it needs to be 
 *	updated in fork.c:copy_process, signal.c:do_signal,
 *	ptrace.c and ptrace.h
 *
 */

#include <linux/config.h>
#include <linux/linkage.h>
#include <linux/sys.h>
#include <asm/unistd.h>
#include <asm/arch/sv_addr_ag.h>
#include <asm/errno.h>
#include <asm/thread_info.h>
#include <asm/arch/offset.h>
#include <asm/page.h>
#include <asm/pgtable.h>

	;; functions exported from this file
	
	.globl system_call
	.globl ret_from_intr
	.globl ret_from_fork
	.globl resume
	.globl multiple_interrupt
	.globl hwbreakpoint
	.globl IRQ1_interrupt
	.globl spurious_interrupt
	.globl hw_bp_trigs
	.globl mmu_bus_fault
	.globl do_sigtrap
	.globl gdb_handle_breakpoint
	.globl sys_call_table
	
	;; below are various parts of system_call which are not in the fast-path
	
#ifdef CONFIG_PREEMPT	
	; Check if preemptive kernel scheduling should be done
_resume_kernel:
	; Load current task struct
	movs.w	-8192, $r0	;  THREAD_SIZE = 8192
	and.d	$sp, $r0
	move.d	[$r0+TI_preempt_count], $r10	;  Preemption disabled?
	bne	_Rexit
	nop
_need_resched:
	move.d	[$r0+TI_flags], $r10
	btstq	TIF_NEED_RESCHED, $r10	; Check if need_resched is set
	bpl	_Rexit
	nop
	; Ok, lets's do some preemptive kernel scheduling
	move.d	PREEMPT_ACTIVE, $r10
	move.d	$r10, [$r0+TI_preempt_count] ; Mark as active
	ei
	jsr	schedule
	clear.d	[$r0+TI_preempt_count] ;  Mark as inactive
	di
	; Load new task struct
	movs.w	-8192, $r0	;  THREAD_SIZE = 8192
	and.d	$sp, $r0
	; One more time (with new task)
	ba	_need_resched
	nop
#else
#define _resume_kernel _Rexit
#endif	

	; Called at exit from fork. schedule_tail must be called to drop
	; spinlock if CONFIG_PREEMPT
ret_from_fork:
	jsr schedule_tail
	ba  ret_from_sys_call
	nop
		
ret_from_intr:
	;; check for resched if preemptive kernel or if we're going back to user-mode 
	;; this test matches the user_regs(regs) macro
	;; we cannot simply test $dccr, because that does not necessarily
	;; reflect what mode we'll return into.
	
	move.d	[$sp + PT_dccr], $r0; regs->dccr
	btstq	8, $r0		; U-flag
	bpl     _resume_kernel
	; Note that di below is in delay slot 
	
_resume_userspace:
	di			; so need_resched and sigpending don't change

	movs.w	-8192, $r0	; THREAD_SIZE == 8192
	and.d	$sp, $r0

	move.d	[$r0+TI_flags], $r10	; current->work
	and.d	_TIF_WORK_MASK, $r10	; is there any work to be done on return
	bne	_work_pending
	nop
	ba	_Rexit
	nop
	
	;; The system_call is called by a BREAK instruction, which works like
	;; an interrupt call but it stores the return PC in BRP instead of IRP.
	;; Since we dont really want to have two epilogues (one for system calls
	;; and one for interrupts) we push the contents of BRP instead of IRP in the
	;; system call prologue, to make it look like an ordinary interrupt on the
	;; stackframe.
	;;
	;; Since we can't have system calls inside interrupts, it should not matter
	;; that we don't stack IRP.
	;; 
	;; In r9 we have the wanted syscall number. Arguments come in r10,r11,r12,r13,mof,srp
	;;
	;; This function looks on the _surface_ like spaghetti programming, but it's
	;; really designed so that the fast-path does not force cache-loading of non-used
	;; instructions. Only the non-common cases cause the outlined code to run..

system_call:
	;; stack-frame similar to the irq heads, which is reversed in ret_from_sys_call
	move	$brp,[$sp=$sp-16]; instruction pointer and room for a fake SBFS frame
	push	$srp
	push	$dccr
	push	$mof
	subq	14*4, $sp		; make room for r0-r13
	movem	$r13, [$sp]	; push r0-r13
	push	$r10		; push orig_r10
	clear.d [$sp=$sp-4]	; frametype == 0, normal stackframe
	
	movs.w	-ENOSYS, $r0
	move.d	$r0, [$sp+PT_r10]	; put the default return value in r10 in the frame

	;; check if this process is syscall-traced

	movs.w	-8192, $r0	; THREAD_SIZE == 8192
	and.d	$sp, $r0
	
	move.d	[$r0+TI_flags], $r0
	btstq   TIF_SYSCALL_TRACE, $r0
	bmi	_syscall_trace_entry
	nop	

_syscall_traced:	

	;; check for sanity in the requested syscall number
	
	cmpu.w	NR_syscalls, $r9	
	bcc	ret_from_sys_call
	lslq	2, $r9		;  multiply by 4, in the delay slot

	;; as a bonus 7th parameter, we give the location on the stack
	;; of the register structure itself. some syscalls need this.

	push	$sp
	
	;; the parameter carrying registers r10, r11, r12 and 13 are intact.
	;; the fifth and sixth parameters (if any) was in mof and srp 
	;; respectively, and we need to put them on the stack.

	push	$srp
	push	$mof
	
	jsr	[$r9+sys_call_table]	; actually do the system call
	addq	3*4, $sp		; pop the mof, srp and regs parameters
	move.d	$r10, [$sp+PT_r10]	; save the return value

	moveq	1, $r9		; "parameter" to ret_from_sys_call to show it was a sys call
	
	;; fall through into ret_from_sys_call to return
	
ret_from_sys_call:
	;; r9 is a parameter - if >=1 we came from a syscall, if 0, from an irq
		
	;; get the current task-struct pointer (see top for defs)

	movs.w	-8192, $r0	; THREAD_SIZE == 8192 
	and.d	$sp, $r0

	di			; make sure need_resched and sigpending don't change
	move.d	[$r0+TI_flags],$r1
	and.d	_TIF_ALLWORK_MASK, $r1
	bne	_syscall_exit_work
	nop

_Rexit:
	;; this epilogue MUST match the prologues in multiple_interrupt, irq.h and ptregs.h
	pop	$r10		; frametype
	bne	_RBFexit	; was not CRIS_FRAME_NORMAL, handle otherwise
	addq	4, $sp		; skip orig_r10, in delayslot
	movem	[$sp+], $r13	; registers r0-r13
	pop	$mof		; multiply overflow register 
	pop	$dccr		; condition codes
	pop	$srp		; subroutine return pointer
	;; now we have a 4-word SBFS frame which we do not want to restore
	;; using RBF since it was not stacked with SBFS. instead we would like to
	;; just get the PC value to restart it with, and skip the rest of
	;; the frame.
	;; Also notice that it's important to use instructions here that
	;; keep the interrupts disabled (since we've already popped DCCR)
	move	[$sp=$sp+16], $p8; pop the SBFS frame from the sp
	jmpu	[$sp-16]	; return through the irp field in the sbfs frame

_RBFexit:
	movem	[$sp+], $r13	; registers r0-r13, in delay slot
	pop	$mof		; multiply overflow register 
	pop	$dccr		; condition codes
	pop	$srp		; subroutine return pointer
	rbf	[$sp+]		; return by popping the CPU status

	;; We get here after doing a syscall if extra work might need to be done
	;; perform syscall exit tracing if needed
	
_syscall_exit_work:
	;; $r0 contains current at this point and irq's are disabled

	move.d  [$r0+TI_flags], $r1
	btstq	TIF_SYSCALL_TRACE, $r1
	bpl	_work_pending
	nop
	
	ei

	move.d	$r9, $r1	; preserve r9
	jsr	do_syscall_trace
	move.d	$r1, $r9
	
	ba	_resume_userspace
	nop
	
_work_pending:
	move.d  [$r0+TI_flags], $r1
	btstq   TIF_NEED_RESCHED, $r1
	bpl	_work_notifysig	; was neither trace nor sched, must be signal/notify
	nop
	
_work_resched:
	move.d	$r9, $r1	; preserve r9
	jsr	schedule
	move.d	$r1, $r9
	di

	move.d	[$r0+TI_flags], $r1
	and.d	_TIF_WORK_MASK, $r1; ignore the syscall trace counter
	beq	_Rexit
	nop
	btstq	TIF_NEED_RESCHED, $r1
	bmi	_work_resched	; current->work.need_resched
	nop

_work_notifysig:
	;; deal with pending signals and notify-resume requests

	move.d	$r9, $r10	; do_notify_resume syscall/irq param
	moveq	0, $r11		; oldset param - 0 in this case
	move.d	$sp, $r12	; the regs param
	move.d  $r1, $r13	; the thread_info_flags parameter
	jsr	do_notify_resume
	
	ba _Rexit
	nop

	;; We get here as a sidetrack when we've entered a syscall with the
	;; trace-bit set. We need to call do_syscall_trace and then continue
	;; with the call.
	
_syscall_trace_entry:
	;; PT_r10 in the frame contains -ENOSYS as required, at this point
	
	jsr	do_syscall_trace

	;; now re-enter the syscall code to do the syscall itself
	;; we need to restore $r9 here to contain the wanted syscall, and
	;; the other parameter-bearing registers

	move.d	[$sp+PT_r9], $r9
	move.d	[$sp+PT_orig_r10], $r10  ; PT_r10 is already filled with -ENOSYS.
	move.d	[$sp+PT_r11],      $r11
	move.d	[$sp+PT_r12],      $r12
	move.d	[$sp+PT_r13],      $r13
	move	[$sp+PT_mof],      $mof
	move	[$sp+PT_srp],      $srp
	
	ba	_syscall_traced
	nop
	
	;; resume performs the actual task-switching, by switching stack pointers
	;; input arguments: r10 = prev, r11 = next, r12 = thread offset in task struct
	;; returns old current in r10
	;;
	;; TODO:  see the i386 version. The switch_to which calls resume in our version
	;;        could really be an inline asm of this.

resume:	
	push	$srp		         ; we keep the old/new PC on the stack 
	add.d	$r12, $r10		 ; r10 = current tasks tss
	move	$dccr, [$r10+THREAD_dccr]; save irq enable state
	di

	move	$usp, [$r10+ THREAD_usp] ; save user-mode stackpointer
	
	;; See copy_thread for the reason why register R9 is saved.
	subq	10*4, $sp
	movem	$r9, [$sp]		 ; save non-scratch registers and R9.
	
	move.d	$sp, [$r10+THREAD_ksp]	 ; save the kernel stack pointer for the old task
	move.d	$sp, $r10		 ; return last running task in r10
	and.d   -8192, $r10	         ; get thread_info from stackpointer
	move.d  [$r10+TI_task], $r10     ; get task  
	add.d	$r12, $r11		 ; find the new tasks tss
	move.d	[$r11+THREAD_ksp], $sp	 ; switch into the new stackframe by restoring kernel sp

	movem	[$sp+], $r9		 ; restore non-scratch registers and R9.

	move	[$r11+THREAD_usp], $usp ; restore user-mode stackpointer
	
	move	[$r11+THREAD_dccr], $dccr ; restore irq enable status
	jump	[$sp+]		         ; restore PC

	;; This is the MMU bus fault handler.
	;; It needs to stack the CPU status and overall is different
	;; from the other interrupt handlers.

mmu_bus_fault:
	;; For refills we try to do a quick page table lookup. If it is
	;; a real fault we let the mm subsystem handle it.

	;; the first longword in the sbfs frame was the interrupted PC
	;; which fits nicely with the "IRP" slot in pt_regs normally used to
	;; contain the return address. used by Oops to print kernel errors.
	sbfs	[$sp=$sp-16]	; push the internal CPU status
	push	$dccr
	di
	subq	2*4, $sp
	movem	$r1, [$sp]
	move.d  [R_MMU_CAUSE], $r1
	;; ETRAX 100LX TR89 bugfix: if the second half of an unaligned
	;; write causes a MMU-fault, it will not be restarted correctly.
	;; This could happen if a write crosses a page-boundary and the
	;; second page is not yet COW'ed or even loaded. The workaround
	;; is to clear the unaligned bit in the CPU status record, so
	;; that the CPU will rerun both the first and second halves of
	;; the instruction. This will not have any sideeffects unless
	;; the first half goes to any device or memory that can't be
	;; written twice, and which is mapped through the MMU.
	;;
	;; We only need to do this for writes.
	btstq	8, $r1		   ; Write access?
	bpl	1f
	nop
	move.d	[$sp+16], $r0	   ; Clear unaligned bit in csrinstr
	and.d	~(1<<5), $r0
	move.d	$r0, [$sp+16]
1:	btstq	12, $r1		   ; Refill?
	bpl	2f
	lsrq	PMD_SHIFT, $r1     ; Get PMD index into PGD (bit 24-31)
	move.d  [current_pgd], $r0 ; PGD for the current process
	move.d	[$r0+$r1.d], $r0   ; Get PMD
	beq	2f
	nop
	and.w	PAGE_MASK, $r0	   ; Remove PMD flags
	move.d  [R_MMU_CAUSE], $r1
	lsrq	PAGE_SHIFT, $r1
	and.d	0x7ff, $r1         ; Get PTE index into PMD (bit 13-24)
	move.d	[$r0+$r1.d], $r1   ; Get PTE
	beq	2f
	nop
	;; Store in TLB
	move.d  $r1, [R_TLB_LO]
	;; Return
	movem	[$sp+], $r1
	pop	$dccr
	rbf	[$sp+]		; return by popping the CPU status

2:	; PMD or PTE missing, let the mm subsystem fix it up.
	movem	[$sp+], $r1
	pop	$dccr

	; Ok, not that easy, pass it on to the mm subsystem
	; The MMU status record is now on the stack
	push	$srp		; make a stackframe similar to pt_regs
	push	$dccr
	push	$mof
	di
	subq	14*4, $sp
	movem	$r13, [$sp]
	push	$r10		; dummy orig_r10
	moveq	1, $r10
	push	$r10		; frametype == 1, BUSFAULT frame type

	move.d	$sp, $r10	; pt_regs argument to handle_mmu_bus_fault
		
	jsr	handle_mmu_bus_fault  ; in arch/cris/arch-v10/mm/fault.c

	;; now we need to return through the normal path, we cannot just
	;; do the RBFexit since we might have killed off the running
	;; process due to a SEGV, scheduled due to a page blocking or
	;; whatever.

	moveq	0, $r9		; busfault is equivalent to an irq
		
	ba	ret_from_intr
	nop
		
	;; special handlers for breakpoint and NMI
hwbreakpoint:
	push	$dccr
	di
	push	$r10
	push	$r11
	move.d	[hw_bp_trig_ptr],$r10
	move	$brp,$r11
	move.d	$r11,[$r10+]
	move.d	$r10,[hw_bp_trig_ptr]
1:	pop	$r11
	pop	$r10
	pop	$dccr
	retb
	nop
	
IRQ1_interrupt:

#if defined(CONFIG_ETRAX_WATCHDOG) && !defined(CONFIG_SVINTO_SIM)
;; If we receive a watchdog interrupt while it is not expected, then set
;; up a canonical frame and dump register contents before dying.

	;; this prologue MUST match the one in irq.h and the struct in ptregs.h!!!
	move	$brp,[$sp=$sp-16]; instruction pointer and room for a fake SBFS frame
	push	$srp
	push	$dccr
	push	$mof
	di
	subq	14*4, $sp
	movem	$r13, [$sp]
	push	$r10		; push orig_r10
	clear.d [$sp=$sp-4]	; frametype == 0, normal frame

;; We don't check that we actually were bit by the watchdog as opposed to
;; an external NMI, since there is currently no handler for external NMI.

;; Check if we're waiting for reset to happen, as signalled by
;; hard_reset_now setting cause_of_death to a magic value.  If so, just
;; get stuck until reset happens.
	.comm	cause_of_death, 4	;; Don't declare this anywhere.
	move.d	[cause_of_death], $r10
	cmp.d	0xbedead, $r10
_killed_by_death:
	beq	_killed_by_death
	nop

;; We'll see this in ksymoops dumps.
Watchdog_bite:

#ifdef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
       ;; We just restart the watchdog here to be sure we dont get
       ;; hit while printing the watchdogmsg below
       ;; This restart is compatible with the rest of the C-code, so
       ;; the C-code can keep restarting the watchdog after this point.
       ;; The non-NICE_DOGGY code below though, disables the possibility
       ;; to restart since it changes the watchdog key, to avoid any
       ;; buggy loops etc. keeping the watchdog alive after this.
       jsr     reset_watchdog
#else

;; We need to extend the 3.3ms after the NMI at watchdog bite, so we have
;; time for an oops-dump over a 115k2 serial wire.  Another 100ms should do.

;; Change the watchdog key to an arbitrary 3-bit value and restart the
;; watchdog.
#define WD_INIT 2
	moveq	  IO_FIELD (R_WATCHDOG, key, WD_INIT), $r10
	move.d	R_WATCHDOG, $r11

	move.d	$r10, [$r11]
	moveq	  IO_FIELD (R_WATCHDOG, key,				\
			    IO_EXTRACT (R_WATCHDOG, key,		\
					IO_MASK (R_WATCHDOG, key))	\
			    ^ WD_INIT)					\
		| IO_STATE (R_WATCHDOG, enable, start), $r10
	move.d	$r10, [$r11]

#endif
	
;; Note that we don't do "setf m" here (or after two necessary NOPs),
;; since *not* doing that saves us from re-entrancy checks.  We don't want
;; to get here again due to possible subsequent NMIs; we want the watchdog
;; to reset us.

	move.d	_watchdogmsg,$r10
	jsr	printk

	move.d	$sp, $r10
	jsr	watchdog_bite_hook

;; This nop is here so we see the "Watchdog_bite" label in ksymoops dumps
;; rather than "spurious_interrupt".
	nop
;; At this point we drop down into spurious_interrupt, which will do a
;; hard reset.

	.section .rodata,"a"
_watchdogmsg:
	.ascii	"Oops: bitten by watchdog\n\0"
	.previous

#endif /* CONFIG_ETRAX_WATCHDOG and not CONFIG_SVINTO_SIM */

spurious_interrupt:	
	di
	jump hard_reset_now

	;; this handles the case when multiple interrupts arrive at the same time
	;; we jump to the first set interrupt bit in a priority fashion
	;; the hardware will call the unserved interrupts after the handler finishes
	
multiple_interrupt:
	;; this prologue MUST match the one in irq.h and the struct in ptregs.h!!!
	move	$irp,[$sp=$sp-16]; instruction pointer and room for a fake SBFS frame
	push	$srp
	push	$dccr
	push	$mof
	di
	subq	14*4, $sp
	movem	$r13, [$sp]
	push	$r10		; push orig_r10
	clear.d [$sp=$sp-4]	; frametype == 0, normal frame
	
	moveq	2, $r2		; first bit we care about is the timer0 irq
	move.d	[R_VECT_MASK_RD], $r0; read the irq bits that triggered the multiple irq
	move.d	$r0, [R_VECT_MASK_CLR] ; Block all active IRQs
1:	
	btst	$r2, $r0	; check for the irq given by bit r2
	bpl	2f
	move.d  $r2, $r10	; First argument to do_IRQ
	move.d  $sp, $r11	; second argument to do_IRQ
	jsr	do_IRQ
2:
	addq	1, $r2		; next vector bit
	cmp.b	32, $r2
	bne	1b	; process all irq's up to and including number 31
	moveq	0, $r9  ; make ret_from_intr realise we came from an ir
	
	move.d	$r0, [R_VECT_MASK_SET] ;  Unblock all the IRQs
	jump    ret_from_intr

do_sigtrap:
	;; 
	;; SIGTRAP the process that executed the break instruction.
	;; Make a frame that Rexit in entry.S expects.
	;;
	move	$brp, [$sp=$sp-16]	; Push BRP while faking a cpu status record.
	push	$srp			; Push subroutine return pointer.
	push	$dccr			; Push condition codes.
	push	$mof			; Push multiply overflow reg.
	di				; Need to disable irq's at this point.
	subq	14*4, $sp		; Make room for r0-r13.
	movem	$r13, [$sp]		; Push the r0-r13 registers.
	push	$r10			; Push orig_r10.
	clear.d	[$sp=$sp-4]		; Frametype - this is a normal stackframe.

	movs.w	-8192,$r9		; THREAD_SIZE == 8192
	and.d	$sp, $r9
	move.d  [$r9+TI_task], $r10
	move.d  [$r10+TASK_pid], $r10	; current->pid as arg1. 
	moveq	5, $r11			; SIGTRAP as arg2.
	jsr	sys_kill       
	jump	ret_from_intr		; Use the return routine for interrupts.

gdb_handle_breakpoint:	
	push	$dccr
	push	$r0
#ifdef CONFIG_ETRAX_KGDB
	move	$dccr, $r0		; U-flag not affected by previous insns. 
	btstq	8, $r0			; Test the U-flag.
	bmi	_ugdb_handle_breakpoint	; Go to user mode debugging. 
	nop				; Empty delay slot (cannot pop r0 here). 
	pop	$r0			; Restore r0.
	ba	kgdb_handle_breakpoint	; Go to kernel debugging. 
	pop	$dccr			; Restore dccr in delay slot.
#endif
	
_ugdb_handle_breakpoint:	
	move	$brp, $r0		; Use r0 temporarily for calculation.
	subq	2, $r0			; Set to address of previous instruction.
	move	$r0, $brp
	pop	$r0			; Restore r0. 
	ba	do_sigtrap		; SIGTRAP the offending process. 
	pop	$dccr			; Restore dccr in delay slot.
	
	.data

hw_bp_trigs:
	.space 64*4
hw_bp_trig_ptr:
	.dword hw_bp_trigs

	.section .rodata,"a"
sys_call_table:	
	.long sys_restart_syscall	/* 0 - old "setup()" system call, used for restarting */
	.long sys_exit
	.long sys_fork
	.long sys_read
	.long sys_write
	.long sys_open		/* 5 */
	.long sys_close
	.long sys_waitpid
	.long sys_creat
	.long sys_link
	.long sys_unlink	/* 10 */
	.long sys_execve
	.long sys_chdir
	.long sys_time
	.long sys_mknod
	.long sys_chmod		/* 15 */
	.long sys_lchown16
	.long sys_ni_syscall	/* old break syscall holder */
	.long sys_stat
	.long sys_lseek
	.long sys_getpid	/* 20 */
	.long sys_mount
	.long sys_oldumount
	.long sys_setuid16
	.long sys_getuid16
	.long sys_stime		/* 25 */
	.long sys_ptrace
	.long sys_alarm
	.long sys_fstat
	.long sys_pause
	.long sys_utime		/* 30 */
	.long sys_ni_syscall	/* old stty syscall holder */
	.long sys_ni_syscall	/* old gtty syscall holder */
	.long sys_access
	.long sys_nice
	.long sys_ni_syscall	/* 35  old ftime syscall holder */
	.long sys_sync
	.long sys_kill
	.long sys_rename
	.long sys_mkdir
	.long sys_rmdir		/* 40 */
	.long sys_dup
	.long sys_pipe
	.long sys_times
	.long sys_ni_syscall	/* old prof syscall holder */
	.long sys_brk		/* 45 */
	.long sys_setgid16
	.long sys_getgid16
	.long sys_signal
	.long sys_geteuid16
	.long sys_getegid16	/* 50 */
	.long sys_acct
	.long sys_umount	/* recycled never used phys( */
	.long sys_ni_syscall	/* old lock syscall holder */
	.long sys_ioctl
	.long sys_fcntl		/* 55 */
	.long sys_ni_syscall	/* old mpx syscall holder */
	.long sys_setpgid
	.long sys_ni_syscall	/* old ulimit syscall holder */
	.long sys_ni_syscall	/* old sys_olduname holder */
	.long sys_umask		/* 60 */
	.long sys_chroot
	.long sys_ustat
	.long sys_dup2
	.long sys_getppid
	.long sys_getpgrp	/* 65 */
	.long sys_setsid
	.long sys_sigaction
	.long sys_sgetmask
	.long sys_ssetmask
	.long sys_setreuid16	/* 70 */
	.long sys_setregid16
	.long sys_sigsuspend
	.long sys_sigpending
	.long sys_sethostname
	.long sys_setrlimit	/* 75 */
	.long sys_old_getrlimit
	.long sys_getrusage
	.long sys_gettimeofday
	.long sys_settimeofday
	.long sys_getgroups16	/* 80 */
	.long sys_setgroups16
	.long sys_select	/* was old_select in Linux/E100 */
	.long sys_symlink
	.long sys_lstat
	.long sys_readlink	/* 85 */
	.long sys_uselib
	.long sys_swapon
	.long sys_reboot
	.long old_readdir
	.long old_mmap		/* 90 */
	.long sys_munmap
	.long sys_truncate
	.long sys_ftruncate
	.long sys_fchmod
	.long sys_fchown16	/* 95 */
	.long sys_getpriority
	.long sys_setpriority
	.long sys_ni_syscall	/* old profil syscall holder */
	.long sys_statfs
	.long sys_fstatfs	/* 100 */
	.long sys_ni_syscall	/* sys_ioperm in i386 */
	.long sys_socketcall
	.long sys_syslog
	.long sys_setitimer
	.long sys_getitimer	/* 105 */
	.long sys_newstat
	.long sys_newlstat
	.long sys_newfstat
	.long sys_ni_syscall	/* old sys_uname holder */
	.long sys_ni_syscall	/* sys_iopl in i386 */
	.long sys_vhangup
	.long sys_ni_syscall	/* old "idle" system call */
	.long sys_ni_syscall	/* vm86old in i386 */
	.long sys_wait4
	.long sys_swapoff	/* 115 */
	.long sys_sysinfo
	.long sys_ipc
	.long sys_fsync
	.long sys_sigreturn
	.long sys_clone		/* 120 */
	.long sys_setdomainname
	.long sys_newuname
	.long sys_ni_syscall	/* sys_modify_ldt */
	.long sys_adjtimex
	.long sys_mprotect	/* 125 */
	.long sys_sigprocmask
	.long sys_ni_syscall	/* old "create_module" */ 
	.long sys_init_module
	.long sys_delete_module
	.long sys_ni_syscall	/* 130:	old "get_kernel_syms" */
	.long sys_quotactl
	.long sys_getpgid
	.long sys_fchdir
	.long sys_bdflush
	.long sys_sysfs		/* 135 */
	.long sys_personality
	.long sys_ni_syscall	/* for afs_syscall */
	.long sys_setfsuid16
	.long sys_setfsgid16
	.long sys_llseek	/* 140 */
	.long sys_getdents
	.long sys_select
	.long sys_flock
	.long sys_msync
	.long sys_readv		/* 145 */
	.long sys_writev
	.long sys_getsid
	.long sys_fdatasync
	.long sys_sysctl
	.long sys_mlock		/* 150 */
	.long sys_munlock
	.long sys_mlockall
	.long sys_munlockall
	.long sys_sched_setparam
	.long sys_sched_getparam	/* 155 */
	.long sys_sched_setscheduler
	.long sys_sched_getscheduler
	.long sys_sched_yield
	.long sys_sched_get_priority_max
	.long sys_sched_get_priority_min	/* 160 */
	.long sys_sched_rr_get_interval
	.long sys_nanosleep
	.long sys_mremap
	.long sys_setresuid16
	.long sys_getresuid16	/* 165 */
	.long sys_ni_syscall	/* sys_vm86 */
	.long sys_ni_syscall	/* Old sys_query_module */
	.long sys_poll
	.long sys_nfsservctl
	.long sys_setresgid16	/* 170 */
	.long sys_getresgid16
	.long sys_prctl
	.long sys_rt_sigreturn
	.long sys_rt_sigaction
	.long sys_rt_sigprocmask	/* 175 */
	.long sys_rt_sigpending
	.long sys_rt_sigtimedwait
	.long sys_rt_sigqueueinfo
	.long sys_rt_sigsuspend
	.long sys_pread64	/* 180 */
	.long sys_pwrite64
	.long sys_chown16
	.long sys_getcwd
	.long sys_capget
	.long sys_capset	/* 185 */
	.long sys_sigaltstack
	.long sys_sendfile
	.long sys_ni_syscall	/* streams1 */
	.long sys_ni_syscall	/* streams2 */
	.long sys_vfork		/* 190 */
	.long sys_getrlimit
	.long sys_mmap2
	.long sys_truncate64
	.long sys_ftruncate64
	.long sys_stat64	/* 195 */
	.long sys_lstat64
	.long sys_fstat64
	.long sys_lchown
	.long sys_getuid
	.long sys_getgid	/* 200 */
	.long sys_geteuid
	.long sys_getegid
	.long sys_setreuid
	.long sys_setregid
	.long sys_getgroups	/* 205 */
	.long sys_setgroups
	.long sys_fchown
	.long sys_setresuid
	.long sys_getresuid
	.long sys_setresgid	/* 210 */
	.long sys_getresgid
	.long sys_chown
	.long sys_setuid
	.long sys_setgid
	.long sys_setfsuid	/* 215 */
	.long sys_setfsgid
	.long sys_pivot_root
	.long sys_mincore
	.long sys_madvise
	.long sys_getdents64	/* 220 */
	.long sys_fcntl64
	.long sys_ni_syscall	/* reserved for TUX */
	.long sys_ni_syscall
	.long sys_gettid
	.long sys_readahead	/* 225 */
	.long sys_setxattr
	.long sys_lsetxattr
	.long sys_fsetxattr
	.long sys_getxattr
	.long sys_lgetxattr	/* 230 */
	.long sys_fgetxattr
	.long sys_listxattr
	.long sys_llistxattr
	.long sys_flistxattr
	.long sys_removexattr	/* 235 */
	.long sys_lremovexattr
	.long sys_fremovexattr
	.long sys_tkill
	.long sys_sendfile64
	.long sys_futex		/* 240 */
	.long sys_sched_setaffinity
	.long sys_sched_getaffinity
	.long sys_ni_syscall	/* sys_set_thread_area */
	.long sys_ni_syscall	/* sys_get_thread_area */
	.long sys_io_setup	/* 245 */
	.long sys_io_destroy
	.long sys_io_getevents
	.long sys_io_submit
	.long sys_io_cancel
	.long sys_fadvise64	/* 250 */
	.long sys_ni_syscall
	.long sys_exit_group
	.long sys_lookup_dcookie
	.long sys_epoll_create
	.long sys_epoll_ctl	/* 255 */
	.long sys_epoll_wait
	.long sys_remap_file_pages
 	.long sys_set_tid_address
 	.long sys_timer_create
 	.long sys_timer_settime		/* 260 */
 	.long sys_timer_gettime
 	.long sys_timer_getoverrun
 	.long sys_timer_delete
 	.long sys_clock_settime
 	.long sys_clock_gettime		/* 265 */
 	.long sys_clock_getres
 	.long sys_clock_nanosleep
	.long sys_statfs64
	.long sys_fstatfs64	
	.long sys_tgkill	/* 270 */
	.long sys_utimes
 	.long sys_fadvise64_64
	.long sys_ni_syscall	/* sys_vserver */
	.long sys_ni_syscall	/* sys_mbind */
	.long sys_ni_syscall	/* 275 sys_get_mempolicy */
	.long sys_ni_syscall	/* sys_set_mempolicy */
	.long sys_mq_open
	.long sys_mq_unlink
	.long sys_mq_timedsend
	.long sys_mq_timedreceive	/* 280 */
	.long sys_mq_notify
	.long sys_mq_getsetattr
	.long sys_ni_syscall		/* reserved for kexec */
	.long sys_waitid

        /*
         * NOTE!! This doesn't have to be exact - we just have
         * to make sure we have _enough_ of the "sys_ni_syscall"
         * entries. Don't panic if you notice that this hasn't
         * been shrunk every time we add a new system call.
         */

	.rept NR_syscalls-(.-sys_call_table)/4
		.long sys_ni_syscall
	.endr