summaryrefslogtreecommitdiff
path: root/arch/powerpc/kernel/head_64.S
blob: ff8511d6d8eadbd03e48ce9c0b639c8d3c80e8aa (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
/*
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
 *    Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
 *  Adapted for Power Macintosh by Paul Mackerras.
 *  Low-level exception handlers and MMU support
 *  rewritten by Paul Mackerras.
 *    Copyright (C) 1996 Paul Mackerras.
 *
 *  Adapted for 64bit PowerPC by Dave Engebretsen, Peter Bergner, and
 *    Mike Corrigan {engebret|bergner|mikejc}@us.ibm.com
 *
 *  This file contains the entry point for the 64-bit kernel along
 *  with some early initialization code common to all 64-bit powerpc
 *  variants.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#include <linux/threads.h>
#include <linux/init.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/ppc_asm.h>
#include <asm/head-64.h>
#include <asm/asm-offsets.h>
#include <asm/bug.h>
#include <asm/cputable.h>
#include <asm/setup.h>
#include <asm/hvcall.h>
#include <asm/thread_info.h>
#include <asm/firmware.h>
#include <asm/page_64.h>
#include <asm/irqflags.h>
#include <asm/kvm_book3s_asm.h>
#include <asm/ptrace.h>
#include <asm/hw_irq.h>
#include <asm/cputhreads.h>
#include <asm/ppc-opcode.h>
#include <asm/export.h>

/* The physical memory is laid out such that the secondary processor
 * spin code sits at 0x0000...0x00ff. On server, the vectors follow
 * using the layout described in exceptions-64s.S
 */

/*
 * Entering into this code we make the following assumptions:
 *
 *  For pSeries or server processors:
 *   1. The MMU is off & open firmware is running in real mode.
 *   2. The kernel is entered at __start
 * -or- For OPAL entry:
 *   1. The MMU is off, processor in HV mode, primary CPU enters at 0
 *      with device-tree in gpr3. We also get OPAL base in r8 and
 *	entry in r9 for debugging purposes
 *   2. Secondary processors enter at 0x60 with PIR in gpr3
 *
 *  For Book3E processors:
 *   1. The MMU is on running in AS0 in a state defined in ePAPR
 *   2. The kernel is entered at __start
 */

OPEN_FIXED_SECTION(first_256B, 0x0, 0x100)
USE_FIXED_SECTION(first_256B)
	/*
	 * Offsets are relative from the start of fixed section, and
	 * first_256B starts at 0. Offsets are a bit easier to use here
	 * than the fixed section entry macros.
	 */
	. = 0x0
_GLOBAL(__start)
	/* NOP this out unconditionally */
BEGIN_FTR_SECTION
	FIXUP_ENDIAN
	b	__start_initialization_multiplatform
END_FTR_SECTION(0, 1)

	/* Catch branch to 0 in real mode */
	trap

	/* Secondary processors spin on this value until it becomes non-zero.
	 * When non-zero, it contains the real address of the function the cpu
	 * should jump to.
	 */
	.balign 8
	.globl  __secondary_hold_spinloop
__secondary_hold_spinloop:
	.8byte	0x0

	/* Secondary processors write this value with their cpu # */
	/* after they enter the spin loop immediately below.	  */
	.globl	__secondary_hold_acknowledge
__secondary_hold_acknowledge:
	.8byte	0x0

#ifdef CONFIG_RELOCATABLE
	/* This flag is set to 1 by a loader if the kernel should run
	 * at the loaded address instead of the linked address.  This
	 * is used by kexec-tools to keep the the kdump kernel in the
	 * crash_kernel region.  The loader is responsible for
	 * observing the alignment requirement.
	 */

#ifdef CONFIG_RELOCATABLE_TEST
#define RUN_AT_LOAD_DEFAULT 1		/* Test relocation, do not copy to 0 */
#else
#define RUN_AT_LOAD_DEFAULT 0x72756e30  /* "run0" -- relocate to 0 by default */
#endif

	/* Do not move this variable as kexec-tools knows about it. */
	. = 0x5c
	.globl	__run_at_load
__run_at_load:
DEFINE_FIXED_SYMBOL(__run_at_load)
	.long	RUN_AT_LOAD_DEFAULT
#endif

	. = 0x60
/*
 * The following code is used to hold secondary processors
 * in a spin loop after they have entered the kernel, but
 * before the bulk of the kernel has been relocated.  This code
 * is relocated to physical address 0x60 before prom_init is run.
 * All of it must fit below the first exception vector at 0x100.
 * Use .globl here not _GLOBAL because we want __secondary_hold
 * to be the actual text address, not a descriptor.
 */
	.globl	__secondary_hold
__secondary_hold:
	FIXUP_ENDIAN
#ifndef CONFIG_PPC_BOOK3E
	mfmsr	r24
	ori	r24,r24,MSR_RI
	mtmsrd	r24			/* RI on */
#endif
	/* Grab our physical cpu number */
	mr	r24,r3
	/* stash r4 for book3e */
	mr	r25,r4

	/* Tell the master cpu we're here */
	/* Relocation is off & we are located at an address less */
	/* than 0x100, so only need to grab low order offset.    */
	std	r24,(ABS_ADDR(__secondary_hold_acknowledge))(0)
	sync

	li	r26,0
#ifdef CONFIG_PPC_BOOK3E
	tovirt(r26,r26)
#endif
	/* All secondary cpus wait here until told to start. */
100:	ld	r12,(ABS_ADDR(__secondary_hold_spinloop))(r26)
	cmpdi	0,r12,0
	beq	100b

#if defined(CONFIG_SMP) || defined(CONFIG_KEXEC_CORE)
#ifdef CONFIG_PPC_BOOK3E
	tovirt(r12,r12)
#endif
	mtctr	r12
	mr	r3,r24
	/*
	 * it may be the case that other platforms have r4 right to
	 * begin with, this gives us some safety in case it is not
	 */
#ifdef CONFIG_PPC_BOOK3E
	mr	r4,r25
#else
	li	r4,0
#endif
	/* Make sure that patched code is visible */
	isync
	bctr
#else
	BUG_OPCODE
#endif
CLOSE_FIXED_SECTION(first_256B)

/* This value is used to mark exception frames on the stack. */
	.section ".toc","aw"
exception_marker:
	.tc	ID_72656773_68657265[TC],0x7265677368657265
	.previous

/*
 * On server, we include the exception vectors code here as it
 * relies on absolute addressing which is only possible within
 * this compilation unit
 */
#ifdef CONFIG_PPC_BOOK3S
#include "exceptions-64s.S"
#else
OPEN_TEXT_SECTION(0x100)
#endif

USE_TEXT_SECTION()

#ifdef CONFIG_PPC_BOOK3E
/*
 * The booting_thread_hwid holds the thread id we want to boot in cpu
 * hotplug case. It is set by cpu hotplug code, and is invalid by default.
 * The thread id is the same as the initial value of SPRN_PIR[THREAD_ID]
 * bit field.
 */
	.globl	booting_thread_hwid
booting_thread_hwid:
	.long  INVALID_THREAD_HWID
	.align 3
/*
 * start a thread in the same core
 * input parameters:
 * r3 = the thread physical id
 * r4 = the entry point where thread starts
 */
_GLOBAL(book3e_start_thread)
	LOAD_REG_IMMEDIATE(r5, MSR_KERNEL)
	cmpwi	r3, 0
	beq	10f
	cmpwi	r3, 1
	beq	11f
	/* If the thread id is invalid, just exit. */
	b	13f
10:
	MTTMR(TMRN_IMSR0, 5)
	MTTMR(TMRN_INIA0, 4)
	b	12f
11:
	MTTMR(TMRN_IMSR1, 5)
	MTTMR(TMRN_INIA1, 4)
12:
	isync
	li	r6, 1
	sld	r6, r6, r3
	mtspr	SPRN_TENS, r6
13:
	blr

/*
 * stop a thread in the same core
 * input parameter:
 * r3 = the thread physical id
 */
_GLOBAL(book3e_stop_thread)
	cmpwi	r3, 0
	beq	10f
	cmpwi	r3, 1
	beq	10f
	/* If the thread id is invalid, just exit. */
	b	13f
10:
	li	r4, 1
	sld	r4, r4, r3
	mtspr	SPRN_TENC, r4
13:
	blr

_GLOBAL(fsl_secondary_thread_init)
	mfspr	r4,SPRN_BUCSR

	/* Enable branch prediction */
	lis     r3,BUCSR_INIT@h
	ori     r3,r3,BUCSR_INIT@l
	mtspr   SPRN_BUCSR,r3
	isync

	/*
	 * Fix PIR to match the linear numbering in the device tree.
	 *
	 * On e6500, the reset value of PIR uses the low three bits for
	 * the thread within a core, and the upper bits for the core
	 * number.  There are two threads per core, so shift everything
	 * but the low bit right by two bits so that the cpu numbering is
	 * continuous.
	 *
	 * If the old value of BUCSR is non-zero, this thread has run
	 * before.  Thus, we assume we are coming from kexec or a similar
	 * scenario, and PIR is already set to the correct value.  This
	 * is a bit of a hack, but there are limited opportunities for
	 * getting information into the thread and the alternatives
	 * seemed like they'd be overkill.  We can't tell just by looking
	 * at the old PIR value which state it's in, since the same value
	 * could be valid for one thread out of reset and for a different
	 * thread in Linux.
	 */

	mfspr	r3, SPRN_PIR
	cmpwi	r4,0
	bne	1f
	rlwimi	r3, r3, 30, 2, 30
	mtspr	SPRN_PIR, r3
1:
#endif

_GLOBAL(generic_secondary_thread_init)
	mr	r24,r3

	/* turn on 64-bit mode */
	bl	enable_64b_mode

	/* get a valid TOC pointer, wherever we're mapped at */
	bl	relative_toc
	tovirt(r2,r2)

#ifdef CONFIG_PPC_BOOK3E
	/* Book3E initialization */
	mr	r3,r24
	bl	book3e_secondary_thread_init
#endif
	b	generic_secondary_common_init

/*
 * On pSeries and most other platforms, secondary processors spin
 * in the following code.
 * At entry, r3 = this processor's number (physical cpu id)
 *
 * On Book3E, r4 = 1 to indicate that the initial TLB entry for
 * this core already exists (setup via some other mechanism such
 * as SCOM before entry).
 */
_GLOBAL(generic_secondary_smp_init)
	FIXUP_ENDIAN
	mr	r24,r3
	mr	r25,r4

	/* turn on 64-bit mode */
	bl	enable_64b_mode

	/* get a valid TOC pointer, wherever we're mapped at */
	bl	relative_toc
	tovirt(r2,r2)

#ifdef CONFIG_PPC_BOOK3E
	/* Book3E initialization */
	mr	r3,r24
	mr	r4,r25
	bl	book3e_secondary_core_init

/*
 * After common core init has finished, check if the current thread is the
 * one we wanted to boot. If not, start the specified thread and stop the
 * current thread.
 */
	LOAD_REG_ADDR(r4, booting_thread_hwid)
	lwz     r3, 0(r4)
	li	r5, INVALID_THREAD_HWID
	cmpw	r3, r5
	beq	20f

	/*
	 * The value of booting_thread_hwid has been stored in r3,
	 * so make it invalid.
	 */
	stw	r5, 0(r4)

	/*
	 * Get the current thread id and check if it is the one we wanted.
	 * If not, start the one specified in booting_thread_hwid and stop
	 * the current thread.
	 */
	mfspr	r8, SPRN_TIR
	cmpw	r3, r8
	beq	20f

	/* start the specified thread */
	LOAD_REG_ADDR(r5, fsl_secondary_thread_init)
	ld	r4, 0(r5)
	bl	book3e_start_thread

	/* stop the current thread */
	mr	r3, r8
	bl	book3e_stop_thread
10:
	b	10b
20:
#endif

generic_secondary_common_init:
	/* Set up a paca value for this processor. Since we have the
	 * physical cpu id in r24, we need to search the pacas to find
	 * which logical id maps to our physical one.
	 */
	LOAD_REG_ADDR(r13, paca)	/* Load paca pointer		 */
	ld	r13,0(r13)		/* Get base vaddr of paca array	 */
#ifndef CONFIG_SMP
	addi	r13,r13,PACA_SIZE	/* know r13 if used accidentally */
	b	kexec_wait		/* wait for next kernel if !SMP	 */
#else
	LOAD_REG_ADDR(r7, nr_cpu_ids)	/* Load nr_cpu_ids address       */
	lwz	r7,0(r7)		/* also the max paca allocated 	 */
	li	r5,0			/* logical cpu id                */
1:	lhz	r6,PACAHWCPUID(r13)	/* Load HW procid from paca      */
	cmpw	r6,r24			/* Compare to our id             */
	beq	2f
	addi	r13,r13,PACA_SIZE	/* Loop to next PACA on miss     */
	addi	r5,r5,1
	cmpw	r5,r7			/* Check if more pacas exist     */
	blt	1b

	mr	r3,r24			/* not found, copy phys to r3	 */
	b	kexec_wait		/* next kernel might do better	 */

2:	SET_PACA(r13)
#ifdef CONFIG_PPC_BOOK3E
	addi	r12,r13,PACA_EXTLB	/* and TLB exc frame in another  */
	mtspr	SPRN_SPRG_TLB_EXFRAME,r12
#endif

	/* From now on, r24 is expected to be logical cpuid */
	mr	r24,r5

	/* See if we need to call a cpu state restore handler */
	LOAD_REG_ADDR(r23, cur_cpu_spec)
	ld	r23,0(r23)
	ld	r12,CPU_SPEC_RESTORE(r23)
	cmpdi	0,r12,0
	beq	3f
#ifdef PPC64_ELF_ABI_v1
	ld	r12,0(r12)
#endif
	mtctr	r12
	bctrl

3:	LOAD_REG_ADDR(r3, spinning_secondaries) /* Decrement spinning_secondaries */
	lwarx	r4,0,r3
	subi	r4,r4,1
	stwcx.	r4,0,r3
	bne	3b
	isync

4:	HMT_LOW
	lbz	r23,PACAPROCSTART(r13)	/* Test if this processor should */
					/* start.			 */
	cmpwi	0,r23,0
	beq	4b			/* Loop until told to go	 */

	sync				/* order paca.run and cur_cpu_spec */
	isync				/* In case code patching happened */

	/* Create a temp kernel stack for use before relocation is on.	*/
	ld	r1,PACAEMERGSP(r13)
	subi	r1,r1,STACK_FRAME_OVERHEAD

	b	__secondary_start
#endif /* SMP */

/*
 * Turn the MMU off.
 * Assumes we're mapped EA == RA if the MMU is on.
 */
#ifdef CONFIG_PPC_BOOK3S
__mmu_off:
	mfmsr	r3
	andi.	r0,r3,MSR_IR|MSR_DR
	beqlr
	mflr	r4
	andc	r3,r3,r0
	mtspr	SPRN_SRR0,r4
	mtspr	SPRN_SRR1,r3
	sync
	rfid
	b	.	/* prevent speculative execution */
#endif


/*
 * Here is our main kernel entry point. We support currently 2 kind of entries
 * depending on the value of r5.
 *
 *   r5 != NULL -> OF entry, we go to prom_init, "legacy" parameter content
 *                 in r3...r7
 *   
 *   r5 == NULL -> kexec style entry. r3 is a physical pointer to the
 *                 DT block, r4 is a physical pointer to the kernel itself
 *
 */
__start_initialization_multiplatform:
	/* Make sure we are running in 64 bits mode */
	bl	enable_64b_mode

	/* Get TOC pointer (current runtime address) */
	bl	relative_toc

	/* find out where we are now */
	bcl	20,31,$+4
0:	mflr	r26			/* r26 = runtime addr here */
	addis	r26,r26,(_stext - 0b)@ha
	addi	r26,r26,(_stext - 0b)@l	/* current runtime base addr */

	/*
	 * Are we booted from a PROM Of-type client-interface ?
	 */
	cmpldi	cr0,r5,0
	beq	1f
	b	__boot_from_prom		/* yes -> prom */
1:
	/* Save parameters */
	mr	r31,r3
	mr	r30,r4
#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL
	/* Save OPAL entry */
	mr	r28,r8
	mr	r29,r9
#endif

#ifdef CONFIG_PPC_BOOK3E
	bl	start_initialization_book3e
	b	__after_prom_start
#else
	/* Setup some critical 970 SPRs before switching MMU off */
	mfspr	r0,SPRN_PVR
	srwi	r0,r0,16
	cmpwi	r0,0x39		/* 970 */
	beq	1f
	cmpwi	r0,0x3c		/* 970FX */
	beq	1f
	cmpwi	r0,0x44		/* 970MP */
	beq	1f
	cmpwi	r0,0x45		/* 970GX */
	bne	2f
1:	bl	__cpu_preinit_ppc970
2:

	/* Switch off MMU if not already off */
	bl	__mmu_off
	b	__after_prom_start
#endif /* CONFIG_PPC_BOOK3E */

__boot_from_prom:
#ifdef CONFIG_PPC_OF_BOOT_TRAMPOLINE
	/* Save parameters */
	mr	r31,r3
	mr	r30,r4
	mr	r29,r5
	mr	r28,r6
	mr	r27,r7

	/*
	 * Align the stack to 16-byte boundary
	 * Depending on the size and layout of the ELF sections in the initial
	 * boot binary, the stack pointer may be unaligned on PowerMac
	 */
	rldicr	r1,r1,0,59

#ifdef CONFIG_RELOCATABLE
	/* Relocate code for where we are now */
	mr	r3,r26
	bl	relocate
#endif

	/* Restore parameters */
	mr	r3,r31
	mr	r4,r30
	mr	r5,r29
	mr	r6,r28
	mr	r7,r27

	/* Do all of the interaction with OF client interface */
	mr	r8,r26
	bl	prom_init
#endif /* #CONFIG_PPC_OF_BOOT_TRAMPOLINE */

	/* We never return. We also hit that trap if trying to boot
	 * from OF while CONFIG_PPC_OF_BOOT_TRAMPOLINE isn't selected */
	trap

__after_prom_start:
#ifdef CONFIG_RELOCATABLE
	/* process relocations for the final address of the kernel */
	lis	r25,PAGE_OFFSET@highest	/* compute virtual base of kernel */
	sldi	r25,r25,32
#if defined(CONFIG_PPC_BOOK3E)
	tovirt(r26,r26)		/* on booke, we already run at PAGE_OFFSET */
#endif
	lwz	r7,(FIXED_SYMBOL_ABS_ADDR(__run_at_load))(r26)
#if defined(CONFIG_PPC_BOOK3E)
	tophys(r26,r26)
#endif
	cmplwi	cr0,r7,1	/* flagged to stay where we are ? */
	bne	1f
	add	r25,r25,r26
1:	mr	r3,r25
	bl	relocate
#if defined(CONFIG_PPC_BOOK3E)
	/* IVPR needs to be set after relocation. */
	bl	init_core_book3e
#endif
#endif

/*
 * We need to run with _stext at physical address PHYSICAL_START.
 * This will leave some code in the first 256B of
 * real memory, which are reserved for software use.
 *
 * Note: This process overwrites the OF exception vectors.
 */
	li	r3,0			/* target addr */
#ifdef CONFIG_PPC_BOOK3E
	tovirt(r3,r3)		/* on booke, we already run at PAGE_OFFSET */
#endif
	mr.	r4,r26			/* In some cases the loader may  */
#if defined(CONFIG_PPC_BOOK3E)
	tovirt(r4,r4)
#endif
	beq	9f			/* have already put us at zero */
	li	r6,0x100		/* Start offset, the first 0x100 */
					/* bytes were copied earlier.	 */

#ifdef CONFIG_RELOCATABLE
/*
 * Check if the kernel has to be running as relocatable kernel based on the
 * variable __run_at_load, if it is set the kernel is treated as relocatable
 * kernel, otherwise it will be moved to PHYSICAL_START
 */
#if defined(CONFIG_PPC_BOOK3E)
	tovirt(r26,r26)		/* on booke, we already run at PAGE_OFFSET */
#endif
	lwz	r7,(FIXED_SYMBOL_ABS_ADDR(__run_at_load))(r26)
	cmplwi	cr0,r7,1
	bne	3f

#ifdef CONFIG_PPC_BOOK3E
	LOAD_REG_ADDR(r5, __end_interrupts)
	LOAD_REG_ADDR(r11, _stext)
	sub	r5,r5,r11
#else
	/* just copy interrupts */
	LOAD_REG_IMMEDIATE(r5, FIXED_SYMBOL_ABS_ADDR(__end_interrupts))
#endif
	b	5f
3:
#endif
	/* # bytes of memory to copy */
	lis	r5,(ABS_ADDR(copy_to_here))@ha
	addi	r5,r5,(ABS_ADDR(copy_to_here))@l

	bl	copy_and_flush		/* copy the first n bytes	 */
					/* this includes the code being	 */
					/* executed here.		 */
	/* Jump to the copy of this code that we just made */
	addis	r8,r3,(ABS_ADDR(4f))@ha
	addi	r12,r8,(ABS_ADDR(4f))@l
	mtctr	r12
	bctr

.balign 8
p_end: .8byte _end - copy_to_here

4:
	/*
	 * Now copy the rest of the kernel up to _end, add
	 * _end - copy_to_here to the copy limit and run again.
	 */
	addis   r8,r26,(ABS_ADDR(p_end))@ha
	ld      r8,(ABS_ADDR(p_end))@l(r8)
	add	r5,r5,r8
5:	bl	copy_and_flush		/* copy the rest */

9:	b	start_here_multiplatform

/*
 * Copy routine used to copy the kernel to start at physical address 0
 * and flush and invalidate the caches as needed.
 * r3 = dest addr, r4 = source addr, r5 = copy limit, r6 = start offset
 * on exit, r3, r4, r5 are unchanged, r6 is updated to be >= r5.
 *
 * Note: this routine *only* clobbers r0, r6 and lr
 */
_GLOBAL(copy_and_flush)
	addi	r5,r5,-8
	addi	r6,r6,-8
4:	li	r0,8			/* Use the smallest common	*/
					/* denominator cache line	*/
					/* size.  This results in	*/
					/* extra cache line flushes	*/
					/* but operation is correct.	*/
					/* Can't get cache line size	*/
					/* from NACA as it is being	*/
					/* moved too.			*/

	mtctr	r0			/* put # words/line in ctr	*/
3:	addi	r6,r6,8			/* copy a cache line		*/
	ldx	r0,r6,r4
	stdx	r0,r6,r3
	bdnz	3b
	dcbst	r6,r3			/* write it to memory		*/
	sync
	icbi	r6,r3			/* flush the icache line	*/
	cmpld	0,r6,r5
	blt	4b
	sync
	addi	r5,r5,8
	addi	r6,r6,8
	isync
	blr

.align 8
copy_to_here:

#ifdef CONFIG_SMP
#ifdef CONFIG_PPC_PMAC
/*
 * On PowerMac, secondary processors starts from the reset vector, which
 * is temporarily turned into a call to one of the functions below.
 */
	.section ".text";
	.align 2 ;

	.globl	__secondary_start_pmac_0
__secondary_start_pmac_0:
	/* NB the entries for cpus 0, 1, 2 must each occupy 8 bytes. */
	li	r24,0
	b	1f
	li	r24,1
	b	1f
	li	r24,2
	b	1f
	li	r24,3
1:
	
_GLOBAL(pmac_secondary_start)
	/* turn on 64-bit mode */
	bl	enable_64b_mode

	li	r0,0
	mfspr	r3,SPRN_HID4
	rldimi	r3,r0,40,23	/* clear bit 23 (rm_ci) */
	sync
	mtspr	SPRN_HID4,r3
	isync
	sync
	slbia

	/* get TOC pointer (real address) */
	bl	relative_toc
	tovirt(r2,r2)

	/* Copy some CPU settings from CPU 0 */
	bl	__restore_cpu_ppc970

	/* pSeries do that early though I don't think we really need it */
	mfmsr	r3
	ori	r3,r3,MSR_RI
	mtmsrd	r3			/* RI on */

	/* Set up a paca value for this processor. */
	LOAD_REG_ADDR(r4,paca)		/* Load paca pointer		*/
	ld	r4,0(r4)		/* Get base vaddr of paca array	*/
	mulli	r13,r24,PACA_SIZE	/* Calculate vaddr of right paca */
	add	r13,r13,r4		/* for this processor.		*/
	SET_PACA(r13)			/* Save vaddr of paca in an SPRG*/

	/* Mark interrupts soft and hard disabled (they might be enabled
	 * in the PACA when doing hotplug)
	 */
	li	r0,0
	stb	r0,PACASOFTIRQEN(r13)
	li	r0,PACA_IRQ_HARD_DIS
	stb	r0,PACAIRQHAPPENED(r13)

	/* Create a temp kernel stack for use before relocation is on.	*/
	ld	r1,PACAEMERGSP(r13)
	subi	r1,r1,STACK_FRAME_OVERHEAD

	b	__secondary_start

#endif /* CONFIG_PPC_PMAC */

/*
 * This function is called after the master CPU has released the
 * secondary processors.  The execution environment is relocation off.
 * The paca for this processor has the following fields initialized at
 * this point:
 *   1. Processor number
 *   2. Segment table pointer (virtual address)
 * On entry the following are set:
 *   r1	       = stack pointer (real addr of temp stack)
 *   r24       = cpu# (in Linux terms)
 *   r13       = paca virtual address
 *   SPRG_PACA = paca virtual address
 */
	.section ".text";
	.align 2 ;

	.globl	__secondary_start
__secondary_start:
	/* Set thread priority to MEDIUM */
	HMT_MEDIUM

	/* Initialize the kernel stack */
	LOAD_REG_ADDR(r3, current_set)
	sldi	r28,r24,3		/* get current_set[cpu#]	 */
	ldx	r14,r3,r28
	addi	r14,r14,THREAD_SIZE-STACK_FRAME_OVERHEAD
	std	r14,PACAKSAVE(r13)

	/* Do early setup for that CPU (SLB and hash table pointer) */
	bl	early_setup_secondary

	/*
	 * setup the new stack pointer, but *don't* use this until
	 * translation is on.
	 */
	mr	r1, r14

	/* Clear backchain so we get nice backtraces */
	li	r7,0
	mtlr	r7

	/* Mark interrupts soft and hard disabled (they might be enabled
	 * in the PACA when doing hotplug)
	 */
	stb	r7,PACASOFTIRQEN(r13)
	li	r0,PACA_IRQ_HARD_DIS
	stb	r0,PACAIRQHAPPENED(r13)

	/* enable MMU and jump to start_secondary */
	LOAD_REG_ADDR(r3, start_secondary_prolog)
	LOAD_REG_IMMEDIATE(r4, MSR_KERNEL)

	mtspr	SPRN_SRR0,r3
	mtspr	SPRN_SRR1,r4
	RFI
	b	.	/* prevent speculative execution */

/* 
 * Running with relocation on at this point.  All we want to do is
 * zero the stack back-chain pointer and get the TOC virtual address
 * before going into C code.
 */
start_secondary_prolog:
	ld	r2,PACATOC(r13)
	li	r3,0
	std	r3,0(r1)		/* Zero the stack frame pointer	*/
	bl	start_secondary
	b	.
/*
 * Reset stack pointer and call start_secondary
 * to continue with online operation when woken up
 * from cede in cpu offline.
 */
_GLOBAL(start_secondary_resume)
	ld	r1,PACAKSAVE(r13)	/* Reload kernel stack pointer */
	li	r3,0
	std	r3,0(r1)		/* Zero the stack frame pointer	*/
	bl	start_secondary
	b	.
#endif

/*
 * This subroutine clobbers r11 and r12
 */
enable_64b_mode:
	mfmsr	r11			/* grab the current MSR */
#ifdef CONFIG_PPC_BOOK3E
	oris	r11,r11,0x8000		/* CM bit set, we'll set ICM later */
	mtmsr	r11
#else /* CONFIG_PPC_BOOK3E */
	li	r12,(MSR_64BIT | MSR_ISF)@highest
	sldi	r12,r12,48
	or	r11,r11,r12
	mtmsrd	r11
	isync
#endif
	blr

/*
 * This puts the TOC pointer into r2, offset by 0x8000 (as expected
 * by the toolchain).  It computes the correct value for wherever we
 * are running at the moment, using position-independent code.
 *
 * Note: The compiler constructs pointers using offsets from the
 * TOC in -mcmodel=medium mode. After we relocate to 0 but before
 * the MMU is on we need our TOC to be a virtual address otherwise
 * these pointers will be real addresses which may get stored and
 * accessed later with the MMU on. We use tovirt() at the call
 * sites to handle this.
 */
_GLOBAL(relative_toc)
	mflr	r0
	bcl	20,31,$+4
0:	mflr	r11
	ld	r2,(p_toc - 0b)(r11)
	add	r2,r2,r11
	mtlr	r0
	blr

.balign 8
p_toc:	.8byte	__toc_start + 0x8000 - 0b

/*
 * This is where the main kernel code starts.
 */
start_here_multiplatform:
	/* set up the TOC */
	bl      relative_toc
	tovirt(r2,r2)

	/* Clear out the BSS. It may have been done in prom_init,
	 * already but that's irrelevant since prom_init will soon
	 * be detached from the kernel completely. Besides, we need
	 * to clear it now for kexec-style entry.
	 */
	LOAD_REG_ADDR(r11,__bss_stop)
	LOAD_REG_ADDR(r8,__bss_start)
	sub	r11,r11,r8		/* bss size			*/
	addi	r11,r11,7		/* round up to an even double word */
	srdi.	r11,r11,3		/* shift right by 3		*/
	beq	4f
	addi	r8,r8,-8
	li	r0,0
	mtctr	r11			/* zero this many doublewords	*/
3:	stdu	r0,8(r8)
	bdnz	3b
4:

#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL
	/* Setup OPAL entry */
	LOAD_REG_ADDR(r11, opal)
	std	r28,0(r11);
	std	r29,8(r11);
#endif

#ifndef CONFIG_PPC_BOOK3E
	mfmsr	r6
	ori	r6,r6,MSR_RI
	mtmsrd	r6			/* RI on */
#endif

#ifdef CONFIG_RELOCATABLE
	/* Save the physical address we're running at in kernstart_addr */
	LOAD_REG_ADDR(r4, kernstart_addr)
	clrldi	r0,r25,2
	std	r0,0(r4)
#endif

	/* The following gets the stack set up with the regs */
	/* pointing to the real addr of the kernel stack.  This is   */
	/* all done to support the C function call below which sets  */
	/* up the htab.  This is done because we have relocated the  */
	/* kernel but are still running in real mode. */

	LOAD_REG_ADDR(r3,init_thread_union)

	/* set up a stack pointer */
	LOAD_REG_IMMEDIATE(r1,THREAD_SIZE)
	add	r1,r3,r1
	li	r0,0
	stdu	r0,-STACK_FRAME_OVERHEAD(r1)

	/*
	 * Do very early kernel initializations, including initial hash table
	 * and SLB setup before we turn on relocation.
	 */

	/* Restore parameters passed from prom_init/kexec */
	mr	r3,r31
	bl	early_setup		/* also sets r13 and SPRG_PACA */

	LOAD_REG_ADDR(r3, start_here_common)
	ld	r4,PACAKMSR(r13)
	mtspr	SPRN_SRR0,r3
	mtspr	SPRN_SRR1,r4
	RFI
	b	.	/* prevent speculative execution */

	/* This is where all platforms converge execution */

start_here_common:
	/* relocation is on at this point */
	std	r1,PACAKSAVE(r13)

	/* Load the TOC (virtual address) */
	ld	r2,PACATOC(r13)

	/* Mark interrupts soft and hard disabled (they might be enabled
	 * in the PACA when doing hotplug)
	 */
	li	r0,0
	stb	r0,PACASOFTIRQEN(r13)
	li	r0,PACA_IRQ_HARD_DIS
	stb	r0,PACAIRQHAPPENED(r13)

	/* Generic kernel entry */
	bl	start_kernel

	/* Not reached */
	BUG_OPCODE

/*
 * We put a few things here that have to be page-aligned.
 * This stuff goes at the beginning of the bss, which is page-aligned.
 */
	.section ".bss"
/*
 * pgd dir should be aligned to PGD_TABLE_SIZE which is 64K.
 * We will need to find a better way to fix this
 */
	.align	16

	.globl	swapper_pg_dir
swapper_pg_dir:
	.space	PGD_TABLE_SIZE

	.globl	empty_zero_page
empty_zero_page:
	.space	PAGE_SIZE
EXPORT_SYMBOL(empty_zero_page)