summaryrefslogtreecommitdiff
path: root/arch/unicore32/kernel/entry.S
blob: bcdedd80890ea29e686d5397256cd1a137bac914 (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
/*
 * linux/arch/unicore32/kernel/entry.S
 *
 * Code specific to PKUnity SoC and UniCore ISA
 *
 * Copyright (C) 2001-2010 GUAN Xue-tao
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  Low-level vector interface routines
 */
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/errno.h>
#include <asm/thread_info.h>
#include <asm/memory.h>
#include <asm/unistd.h>
#include <generated/asm-offsets.h>
#include "debug-macro.S"

@
@ Most of the stack format comes from struct pt_regs, but with
@ the addition of 8 bytes for storing syscall args 5 and 6.
@
#define S_OFF		8

/*
 * The SWI code relies on the fact that R0 is at the bottom of the stack
 * (due to slow/fast restore user regs).
 */
#if S_R0 != 0
#error "Please fix"
#endif

	.macro	zero_fp
#ifdef CONFIG_FRAME_POINTER
	mov	fp, #0
#endif
	.endm

	.macro	alignment_trap, rtemp
#ifdef CONFIG_ALIGNMENT_TRAP
	ldw	\rtemp, .LCcralign
	ldw	\rtemp, [\rtemp]
	movc	p0.c1, \rtemp, #0
#endif
	.endm

	.macro	load_user_sp_lr, rd, rtemp, offset = 0
	mov	\rtemp, asr
	xor	\rtemp, \rtemp, #(PRIV_MODE ^ SUSR_MODE)
	mov.a	asr, \rtemp			@ switch to the SUSR mode

	ldw	sp, [\rd+], #\offset		@ load sp_user
	ldw	lr, [\rd+], #\offset + 4	@ load lr_user

	xor	\rtemp, \rtemp, #(PRIV_MODE ^ SUSR_MODE)
	mov.a	asr, \rtemp			@ switch back to the PRIV mode
	.endm

	.macro	priv_exit, rpsr
	mov.a	bsr, \rpsr
	ldm.w	(r0 - r15), [sp]+
	ldm.b	(r16 - pc), [sp]+		@ load r0 - pc, asr
	.endm

	.macro	restore_user_regs, fast = 0, offset = 0
	ldw	r1, [sp+], #\offset + S_PSR	@ get calling asr
	ldw	lr, [sp+], #\offset + S_PC	@ get pc
	mov.a	bsr, r1				@ save in bsr_priv
	.if	\fast
	add	sp, sp, #\offset + S_R1		@ r0 is syscall return value
	ldm.w	(r1 - r15), [sp]+		@ get calling r1 - r15
	ldur	(r16 - lr), [sp]+		@ get calling r16 - lr
	.else
	ldm.w	(r0 - r15), [sp]+		@ get calling r0 - r15
	ldur	(r16 - lr), [sp]+		@ get calling r16 - lr
	.endif
	nop
	add	sp, sp, #S_FRAME_SIZE - S_R16
	mov.a	pc, lr				@ return
						@ and move bsr_priv into asr
	.endm

	.macro	get_thread_info, rd
	mov	\rd, sp >> #13
	mov	\rd, \rd << #13
	.endm

	.macro	get_irqnr_and_base, irqnr, irqstat, base, tmp
	ldw	\base, =(PKUNITY_INTC_BASE)
	ldw	\irqstat, [\base+], #0xC	@ INTC_ICIP
	ldw	\tmp,	  [\base+], #0x4	@ INTC_ICMR
	and.a	\irqstat, \irqstat, \tmp
	beq	1001f
	cntlz	\irqnr, \irqstat
	rsub	\irqnr, \irqnr, #31
1001:	/* EQ will be set if no irqs pending */
	.endm

#ifdef CONFIG_DEBUG_LL
	.macro	printreg, reg, temp
		adr	\temp, 901f
		stm	(r0-r3), [\temp]+
		stw	lr, [\temp+], #0x10
		mov	r0, \reg
		b.l	printhex8
		mov	r0, #':'
		b.l	printch
		mov	r0, pc
		b.l	printhex8
		adr	r0, 902f
		b.l	printascii
		adr	\temp, 901f
		ldm	(r0-r3), [\temp]+
		ldw	lr, [\temp+], #0x10
		b	903f
901:	.word	0, 0, 0, 0, 0	@ r0-r3, lr
902:	.asciz	": epip4d\n"
	.align
903:
	.endm
#endif

/*
 * These are the registers used in the syscall handler, and allow us to
 * have in theory up to 7 arguments to a function - r0 to r6.
 *
 * Note that tbl == why is intentional.
 *
 * We must set at least "tsk" and "why" when calling ret_with_reschedule.
 */
scno	.req	r21		@ syscall number
tbl	.req	r22		@ syscall table pointer
why	.req	r22		@ Linux syscall (!= 0)
tsk	.req	r23		@ current thread_info

/*
 * Interrupt handling.  Preserves r17, r18, r19
 */
	.macro	intr_handler
1:	get_irqnr_and_base r0, r6, r5, lr
	beq	2f
	mov	r1, sp
	@
	@ routine called with r0 = irq number, r1 = struct pt_regs *
	@
	adr	lr, 1b
	b	asm_do_IRQ
2:
	.endm

/*
 * PRIV mode handlers
 */
	.macro	priv_entry
	sub	sp, sp, #(S_FRAME_SIZE - 4)
	stm	(r1 - r15), [sp]+
	add	r5, sp, #S_R15
	stm	(r16 - r28), [r5]+

	ldm	(r1 - r3), [r0]+
	add	r5, sp, #S_SP - 4	@ here for interlock avoidance
	mov	r4, #-1			@  ""  ""      ""       ""
	add	r0, sp, #(S_FRAME_SIZE - 4)
	stw.w	r1, [sp+], #-4		@ save the "real" r0 copied
					@ from the exception stack

	mov	r1, lr

	@
	@ We are now ready to fill in the remaining blanks on the stack:
	@
	@  r0 - sp_priv
	@  r1 - lr_priv
	@  r2 - lr_<exception>, already fixed up for correct return/restart
	@  r3 - bsr_<exception>
	@  r4 - orig_r0 (see pt_regs definition in ptrace.h)
	@
	stm	(r0 - r4), [r5]+
	.endm

/*
 * User mode handlers
 *
 */
	.macro	user_entry
	sub	sp, sp, #S_FRAME_SIZE
	stm	(r1 - r15), [sp+]
	add	r4, sp, #S_R16
	stm	(r16 - r28), [r4]+

	ldm	(r1 - r3), [r0]+
	add	r0, sp, #S_PC		@ here for interlock avoidance
	mov	r4, #-1			@  ""  ""     ""        ""

	stw	r1, [sp]		@ save the "real" r0 copied
					@ from the exception stack

	@
	@ We are now ready to fill in the remaining blanks on the stack:
	@
	@  r2 - lr_<exception>, already fixed up for correct return/restart
	@  r3 - bsr_<exception>
	@  r4 - orig_r0 (see pt_regs definition in ptrace.h)
	@
	@ Also, separately save sp_user and lr_user
	@
	stm	(r2 - r4), [r0]+
	stur	(sp, lr), [r0-]

	@
	@ Enable the alignment trap while in kernel mode
	@
	alignment_trap r0

	@
	@ Clear FP to mark the first stack frame
	@
	zero_fp
	.endm

	.text

@
@ __invalid - generic code for failed exception
@			(re-entrant version of handlers)
@
__invalid:
	sub	sp, sp, #S_FRAME_SIZE
	stm	(r1 - r15), [sp+]
	add	r1, sp, #S_R16
	stm	(r16 - r28, sp, lr), [r1]+

	zero_fp

	ldm	(r4 - r6), [r0]+
	add	r0, sp, #S_PC		@ here for interlock avoidance
	mov	r7, #-1			@  ""   ""    ""        ""
	stw	r4, [sp]		@ save preserved r0
	stm	(r5 - r7), [r0]+	@ lr_<exception>,
					@ asr_<exception>, "old_r0"

	mov	r0, sp
	mov	r1, asr
	b	bad_mode
ENDPROC(__invalid)

	.align	5
__dabt_priv:
	priv_entry

	@
	@ get ready to re-enable interrupts if appropriate
	@
	mov	r17, asr
	cand.a	r3, #PSR_I_BIT
	bne	1f
	andn	r17, r17, #PSR_I_BIT
1:

	@
	@ Call the processor-specific abort handler:
	@
	@  r2 - aborted context pc
	@  r3 - aborted context asr
	@
	@ The abort handler must return the aborted address in r0, and
	@ the fault status register in r1.
	@
	movc	r1, p0.c3, #0		@ get FSR
	movc	r0, p0.c4, #0		@ get FAR

	@
	@ set desired INTR state, then call main handler
	@
	mov.a	asr, r17
	mov	r2, sp
	b.l	do_DataAbort

	@
	@ INTRs off again before pulling preserved data off the stack
	@
	disable_irq r0

	@
	@ restore BSR and restart the instruction
	@
	ldw	r2, [sp+], #S_PSR
	priv_exit r2				@ return from exception
ENDPROC(__dabt_priv)

	.align	5
__intr_priv:
	priv_entry

	intr_handler

	mov	r0, #0				@ epip4d
	movc	p0.c5, r0, #14
	nop; nop; nop; nop; nop; nop; nop; nop

	ldw	r4, [sp+], #S_PSR		@ irqs are already disabled

	priv_exit r4				@ return from exception
ENDPROC(__intr_priv)

	.ltorg

	.align	5
__extn_priv:
	priv_entry

	mov	r0, sp				@ struct pt_regs *regs
	mov	r1, asr
	b	bad_mode			@ not supported
ENDPROC(__extn_priv)

	.align	5
__pabt_priv:
	priv_entry

	@
	@ re-enable interrupts if appropriate
	@
	mov	r17, asr
	cand.a	r3, #PSR_I_BIT
	bne	1f
	andn	r17, r17, #PSR_I_BIT
1:

	@
	@ set args, then call main handler
	@
	@  r0 - address of faulting instruction
	@  r1 - pointer to registers on stack
	@
	mov	r0, r2			@ pass address of aborted instruction
	mov	r1, #5
	mov.a	asr, r17
	mov	r2, sp			@ regs
	b.l	do_PrefetchAbort	@ call abort handler

	@
	@ INTRs off again before pulling preserved data off the stack
	@
	disable_irq r0

	@
	@ restore BSR and restart the instruction
	@
	ldw	r2, [sp+], #S_PSR
	priv_exit r2			@ return from exception
ENDPROC(__pabt_priv)

	.align	5
.LCcralign:
	.word	cr_alignment

	.align	5
__dabt_user:
	user_entry

#ifdef CONFIG_UNICORE_FPU_F64
	cff	ip, s31
	cand.a	ip, #0x08000000		@ FPU execption traps?
	beq	209f

	ldw	ip, [sp+], #S_PC
	add	ip, ip, #4
	stw	ip, [sp+], #S_PC
	@
	@ fall through to the emulation code, which returns using r19 if
	@ it has emulated the instruction, or the more conventional lr
	@ if we are to treat this as a real extended instruction
	@
	@  r0 - instruction
	@
1:	ldw.u	r0, [r2]
	adr	r19, ret_from_exception
	adr	lr, 209f
	@
	@ fallthrough to call do_uc_f64
	@
/*
 * Check whether the instruction is a co-processor instruction.
 * If yes, we need to call the relevant co-processor handler.
 *
 * Note that we don't do a full check here for the co-processor
 * instructions; all instructions with bit 27 set are well
 * defined.  The only instructions that should fault are the
 * co-processor instructions.
 *
 * Emulators may wish to make use of the following registers:
 *  r0  = instruction opcode.
 *  r2  = PC
 *  r19 = normal "successful" return address
 *  r20 = this threads thread_info structure.
 *  lr  = unrecognised instruction return address
 */
	get_thread_info r20			@ get current thread
	and	r8, r0, #0x00003c00		@ mask out CP number
	mov	r7, #1
	stb	r7, [r20+], #TI_USED_CP + 2	@ set appropriate used_cp[]

	@ F64 hardware support entry point.
	@  r0  = faulted instruction
	@  r19 = return address
	@  r20 = fp_state
	enable_irq r4
	add	r20, r20, #TI_FPSTATE	@ r20 = workspace
	cff	r1, s31			@ get fpu FPSCR
	andn    r2, r1, #0x08000000
	ctf     r2, s31			@ clear 27 bit
	mov	r2, sp			@ nothing stacked - regdump is at TOS
	mov	lr, r19			@ setup for a return to the user code

	@ Now call the C code to package up the bounce to the support code
	@   r0 holds the trigger instruction
	@   r1 holds the FPSCR value
	@   r2 pointer to register dump
	b	ucf64_exchandler
209:
#endif
	@
	@ Call the processor-specific abort handler:
	@
	@  r2 - aborted context pc
	@  r3 - aborted context asr
	@
	@ The abort handler must return the aborted address in r0, and
	@ the fault status register in r1.
	@
	movc	r1, p0.c3, #0		@ get FSR
	movc	r0, p0.c4, #0		@ get FAR

	@
	@ INTRs on, then call the main handler
	@
	enable_irq r2
	mov	r2, sp
	adr	lr, ret_from_exception
	b	do_DataAbort
ENDPROC(__dabt_user)

	.align	5
__intr_user:
	user_entry

	get_thread_info tsk

	intr_handler

	mov	why, #0
	b	ret_to_user
ENDPROC(__intr_user)

	.ltorg

	.align	5
__extn_user:
	user_entry

	mov	r0, sp
	mov	r1, asr
	b	bad_mode
ENDPROC(__extn_user)

	.align	5
__pabt_user:
	user_entry

	mov	r0, r2			@ pass address of aborted instruction.
	mov	r1, #5
	enable_irq r1			@ Enable interrupts
	mov	r2, sp			@ regs
	b.l	do_PrefetchAbort	@ call abort handler
	/* fall through */
/*
 * This is the return code to user mode for abort handlers
 */
ENTRY(ret_from_exception)
	get_thread_info tsk
	mov	why, #0
	b	ret_to_user
ENDPROC(__pabt_user)
ENDPROC(ret_from_exception)

/*
 * Register switch for UniCore V2 processors
 * r0 = previous task_struct, r1 = previous thread_info, r2 = next thread_info
 * previous and next are guaranteed not to be the same.
 */
ENTRY(__switch_to)
	add	ip, r1, #TI_CPU_SAVE
	stm.w	(r4 - r15), [ip]+
	stm.w	(r16 - r27, sp, lr), [ip]+

#ifdef	CONFIG_UNICORE_FPU_F64
	add	ip, r1, #TI_FPSTATE
	sfm.w	(f0  - f7 ), [ip]+
	sfm.w	(f8  - f15), [ip]+
	sfm.w	(f16 - f23), [ip]+
	sfm.w	(f24 - f31), [ip]+
	cff	r4, s31
	stw	r4, [ip]

	add	ip, r2, #TI_FPSTATE
	lfm.w	(f0  - f7 ), [ip]+
	lfm.w	(f8  - f15), [ip]+
	lfm.w	(f16 - f23), [ip]+
	lfm.w	(f24 - f31), [ip]+
	ldw	r4, [ip]
	ctf	r4, s31
#endif
	add	ip, r2, #TI_CPU_SAVE
	ldm.w	(r4 - r15), [ip]+
	ldm	(r16 - r27, sp, pc), [ip]+	@ Load all regs saved previously
ENDPROC(__switch_to)

	.align	5
/*
 * This is the fast syscall return path.  We do as little as
 * possible here, and this includes saving r0 back into the PRIV
 * stack.
 */
ret_fast_syscall:
	disable_irq r1				@ disable interrupts
	ldw	r1, [tsk+], #TI_FLAGS
	cand.a	r1, #_TIF_WORK_MASK
	bne	fast_work_pending

	@ fast_restore_user_regs
	restore_user_regs fast = 1, offset = S_OFF

/*
 * Ok, we need to do extra processing, enter the slow path.
 */
fast_work_pending:
	stw.w	r0, [sp+], #S_R0+S_OFF		@ returned r0
work_pending:
	cand.a	r1, #_TIF_NEED_RESCHED
	bne	work_resched
	mov	r0, sp				@ 'regs'
	mov	r2, why				@ 'syscall'
	cand.a	r1, #_TIF_SIGPENDING		@ delivering a signal?
	cmovne	why, #0				@ prevent further restarts
	b.l	do_notify_resume
	b	ret_slow_syscall		@ Check work again

work_resched:
	b.l	schedule
/*
 * "slow" syscall return path.  "why" tells us if this was a real syscall.
 */
ENTRY(ret_to_user)
ret_slow_syscall:
	disable_irq r1				@ disable interrupts
	get_thread_info tsk			@ epip4d, one path error?!
	ldw	r1, [tsk+], #TI_FLAGS
	cand.a	r1, #_TIF_WORK_MASK
	bne	work_pending
no_work_pending:
	@ slow_restore_user_regs
	restore_user_regs fast = 0, offset = 0
ENDPROC(ret_to_user)

/*
 * This is how we return from a fork.
 */
ENTRY(ret_from_fork)
	b.l	schedule_tail
	b	ret_slow_syscall
ENDPROC(ret_from_fork)

ENTRY(ret_from_kernel_thread)
	b.l	schedule_tail
	mov	r0, r5
	adr	lr, ret_slow_syscall
	mov	pc, r4
ENDPROC(ret_from_kernel_thread)

/*=============================================================================
 * SWI handler
 *-----------------------------------------------------------------------------
 */
	.align	5
ENTRY(vector_swi)
	sub	sp, sp, #S_FRAME_SIZE
	stm	(r0 - r15), [sp]+		@ Calling r0 - r15
	add	r8, sp, #S_R16
	stm	(r16 - r28), [r8]+		@ Calling r16 - r28
	add	r8, sp, #S_PC
	stur	(sp, lr), [r8-]			@ Calling sp, lr
	mov	r8, bsr				@ called from non-REAL mode
	stw	lr, [sp+], #S_PC		@ Save calling PC
	stw	r8, [sp+], #S_PSR		@ Save ASR
	stw	r0, [sp+], #S_OLD_R0		@ Save OLD_R0
	zero_fp

	/*
	 * Get the system call number.
	 */
	sub	ip, lr, #4
	ldw.u	scno, [ip]			@ get SWI instruction

#ifdef CONFIG_ALIGNMENT_TRAP
	ldw	ip, __cr_alignment
	ldw	ip, [ip]
	movc	p0.c1, ip, #0                   @ update control register
#endif
	enable_irq ip

	get_thread_info tsk
	ldw	tbl, =sys_call_table		@ load syscall table pointer

	andn	scno, scno, #0xff000000		@ mask off SWI op-code
	andn	scno, scno, #0x00ff0000		@ mask off SWI op-code

	stm.w	(r4, r5), [sp-]			@ push fifth and sixth args
	ldw	ip, [tsk+], #TI_FLAGS		@ check for syscall tracing
	cand.a	ip, #_TIF_SYSCALL_TRACE		@ are we tracing syscalls?
	bne	__sys_trace

	csub.a	scno, #__NR_syscalls		@ check upper syscall limit
	adr	lr, ret_fast_syscall		@ return address
	bea	1f
	ldw	pc, [tbl+], scno << #2		@ call sys_* routine
1:
	add	r1, sp, #S_OFF
2:	mov	why, #0				@ no longer a real syscall
	b	sys_ni_syscall			@ not private func

	/*
	 * This is the really slow path.  We're going to be doing
	 * context switches, and waiting for our parent to respond.
	 */
__sys_trace:
	mov	r2, scno
	add	r1, sp, #S_OFF
	mov	r0, #0				@ trace entry [IP = 0]
	b.l	syscall_trace

	adr	lr, __sys_trace_return		@ return address
	mov	scno, r0			@ syscall number (possibly new)
	add	r1, sp, #S_R0 + S_OFF		@ pointer to regs
	csub.a	scno, #__NR_syscalls		@ check upper syscall limit
	bea	2b
	ldm	(r0 - r3), [r1]+		@ have to reload r0 - r3
	ldw	pc, [tbl+], scno << #2		@ call sys_* routine

__sys_trace_return:
	stw.w	r0, [sp+], #S_R0 + S_OFF	@ save returned r0
	mov	r2, scno
	mov	r1, sp
	mov	r0, #1				@ trace exit [IP = 1]
	b.l	syscall_trace
	b	ret_slow_syscall

	.align	5
#ifdef CONFIG_ALIGNMENT_TRAP
	.type	__cr_alignment, #object
__cr_alignment:
	.word	cr_alignment
#endif
	.ltorg

ENTRY(sys_rt_sigreturn)
		add	r0, sp, #S_OFF
		mov	why, #0		@ prevent syscall restart handling
		b	__sys_rt_sigreturn
ENDPROC(sys_rt_sigreturn)

	__INIT

/*
 * Vector stubs.
 *
 * This code is copied to 0xffff0200 so we can use branches in the
 * vectors, rather than ldr's.  Note that this code must not
 * exceed 0x300 bytes.
 *
 * Common stub entry macro:
 *   Enter in INTR mode, bsr = PRIV/USER ASR, lr = PRIV/USER PC
 *
 * SP points to a minimal amount of processor-private memory, the address
 * of which is copied into r0 for the mode specific abort handler.
 */
	.macro	vector_stub, name, mode
	.align	5

vector_\name:
	@
	@ Save r0, lr_<exception> (parent PC) and bsr_<exception>
	@ (parent ASR)
	@
	stw	r0, [sp]
	stw	lr, [sp+], #4		@ save r0, lr
	mov	lr, bsr
	stw	lr, [sp+], #8		@ save bsr

	@
	@ Prepare for PRIV mode.  INTRs remain disabled.
	@
	mov	r0, asr
	xor	r0, r0, #(\mode ^ PRIV_MODE)
	mov.a	bsr, r0

	@
	@ the branch table must immediately follow this code
	@
	and	lr, lr, #0x03
	add	lr, lr, #1
	mov	r0, sp
	ldw	lr, [pc+], lr << #2
	mov.a	pc, lr			@ branch to handler in PRIV mode
ENDPROC(vector_\name)
	.align	2
	@ handler addresses follow this label
	.endm

	.globl	__stubs_start
__stubs_start:
/*
 * Interrupt dispatcher
 */
	vector_stub	intr, INTR_MODE

	.long	__intr_user			@  0  (USER)
	.long	__invalid			@  1
	.long	__invalid			@  2
	.long	__intr_priv			@  3  (PRIV)

/*
 * Data abort dispatcher
 * Enter in ABT mode, bsr = USER ASR, lr = USER PC
 */
	vector_stub	dabt, ABRT_MODE

	.long	__dabt_user			@  0  (USER)
	.long	__invalid			@  1
	.long	__invalid			@  2  (INTR)
	.long	__dabt_priv			@  3  (PRIV)

/*
 * Prefetch abort dispatcher
 * Enter in ABT mode, bsr = USER ASR, lr = USER PC
 */
	vector_stub	pabt, ABRT_MODE

	.long	__pabt_user			@  0 (USER)
	.long	__invalid			@  1
	.long	__invalid			@  2 (INTR)
	.long	__pabt_priv			@  3 (PRIV)

/*
 * Undef instr entry dispatcher
 * Enter in EXTN mode, bsr = PRIV/USER ASR, lr = PRIV/USER PC
 */
	vector_stub	extn, EXTN_MODE

	.long	__extn_user			@  0 (USER)
	.long	__invalid			@  1
	.long	__invalid			@  2 (INTR)
	.long	__extn_priv			@  3 (PRIV)

/*
 * We group all the following data together to optimise
 * for CPUs with separate I & D caches.
 */
	.align	5

.LCvswi:
	.word	vector_swi

	.globl	__stubs_end
__stubs_end:

	.equ	stubs_offset, __vectors_start + 0x200 - __stubs_start

	.globl	__vectors_start
__vectors_start:
	jepriv	SYS_ERROR0
	b	vector_extn + stubs_offset
	ldw	pc, .LCvswi + stubs_offset
	b	vector_pabt + stubs_offset
	b	vector_dabt + stubs_offset
	jepriv	SYS_ERROR0
	b	vector_intr + stubs_offset
	jepriv	SYS_ERROR0

	.globl	__vectors_end
__vectors_end:

	.data

	.globl	cr_alignment
	.globl	cr_no_alignment
cr_alignment:
	.space	4
cr_no_alignment:
	.space	4