aboutsummaryrefslogtreecommitdiffstats
path: root/arch/ia64/sn/kernel/xpc_partition.c
blob: 2c3c4a8af553d181e5e772242e6df9442842f53a (plain) (blame)
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
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 2004-2005 Silicon Graphics, Inc.  All Rights Reserved.
 */


/*
 * Cross Partition Communication (XPC) partition support.
 *
 *	This is the part of XPC that detects the presence/absence of
 *	other partitions. It provides a heartbeat and monitors the
 *	heartbeats of other partitions.
 *
 */


#include <linux/kernel.h>
#include <linux/sysctl.h>
#include <linux/cache.h>
#include <linux/mmzone.h>
#include <linux/nodemask.h>
#include <asm/sn/bte.h>
#include <asm/sn/intr.h>
#include <asm/sn/sn_sal.h>
#include <asm/sn/nodepda.h>
#include <asm/sn/addrs.h>
#include "xpc.h"


/* XPC is exiting flag */
int xpc_exiting;


/* SH_IPI_ACCESS shub register value on startup */
static u64 xpc_sh1_IPI_access;
static u64 xpc_sh2_IPI_access0;
static u64 xpc_sh2_IPI_access1;
static u64 xpc_sh2_IPI_access2;
static u64 xpc_sh2_IPI_access3;


/* original protection values for each node */
u64 xpc_prot_vec[MAX_COMPACT_NODES];


/* this partition's reserved page */
struct xpc_rsvd_page *xpc_rsvd_page;

/* this partition's XPC variables (within the reserved page) */
struct xpc_vars *xpc_vars;
struct xpc_vars_part *xpc_vars_part;


/*
 * For performance reasons, each entry of xpc_partitions[] is cacheline
 * aligned. And xpc_partitions[] is padded with an additional entry at the
 * end so that the last legitimate entry doesn't share its cacheline with
 * another variable.
 */
struct xpc_partition xpc_partitions[XP_MAX_PARTITIONS + 1];


/*
 * Generic buffer used to store a local copy of the remote partitions
 * reserved page or XPC variables.
 *
 * xpc_discovery runs only once and is a seperate thread that is
 * very likely going to be processing in parallel with receiving
 * interrupts.
 */
char ____cacheline_aligned
		xpc_remote_copy_buffer[XPC_RSVD_PAGE_ALIGNED_SIZE];


/* systune related variables */
int xpc_hb_interval = XPC_HB_DEFAULT_INTERVAL;
int xpc_hb_check_interval = XPC_HB_CHECK_DEFAULT_TIMEOUT;


/*
 * Given a nasid, get the physical address of the  partition's reserved page
 * for that nasid. This function returns 0 on any error.
 */
static u64
xpc_get_rsvd_page_pa(int nasid, u64 buf, u64 buf_size)
{
	bte_result_t bte_res;
	s64 status;
	u64 cookie = 0;
	u64 rp_pa = nasid;	/* seed with nasid */
	u64 len = 0;


	while (1) {

		status = sn_partition_reserved_page_pa(buf, &cookie, &rp_pa,
								&len);

		dev_dbg(xpc_part, "SAL returned with status=%li, cookie="
			"0x%016lx, address=0x%016lx, len=0x%016lx\n",
			status, cookie, rp_pa, len);

		if (status != SALRET_MORE_PASSES) {
			break;
		}

		if (len > buf_size) {
			dev_err(xpc_part, "len (=0x%016lx) > buf_size\n", len);
			status = SALRET_ERROR;
			break;
		}

		bte_res = xp_bte_copy(rp_pa, ia64_tpa(buf), buf_size,
					(BTE_NOTIFY | BTE_WACQUIRE), NULL);
		if (bte_res != BTE_SUCCESS) {
			dev_dbg(xpc_part, "xp_bte_copy failed %i\n", bte_res);
			status = SALRET_ERROR;
			break;
		}
	}

	if (status != SALRET_OK) {
		rp_pa = 0;
	}
	dev_dbg(xpc_part, "reserved page at phys address 0x%016lx\n", rp_pa);
	return rp_pa;
}


/*
 * Fill the partition reserved page with the information needed by
 * other partitions to discover we are alive and establish initial
 * communications.
 */
struct xpc_rsvd_page *
xpc_rsvd_page_init(void)
{
	struct xpc_rsvd_page *rp;
	AMO_t *amos_page;
	u64 rp_pa, next_cl, nasid_array = 0;
	int i, ret;


	/* get the local reserved page's address */

	rp_pa = xpc_get_rsvd_page_pa(cnodeid_to_nasid(0),
					(u64) xpc_remote_copy_buffer,
						XPC_RSVD_PAGE_ALIGNED_SIZE);
	if (rp_pa == 0) {
		dev_err(xpc_part, "SAL failed to locate the reserved page\n");
		return NULL;
	}
	rp = (struct xpc_rsvd_page *) __va(rp_pa);

	if (rp->partid != sn_partition_id) {
		dev_err(xpc_part, "the reserved page's partid of %d should be "
			"%d\n", rp->partid, sn_partition_id);
		return NULL;
	}

	rp->version = XPC_RP_VERSION;

	/*
	 * Place the XPC variables on the cache line following the
	 * reserved page structure.
	 */
	next_cl = (u64) rp + XPC_RSVD_PAGE_ALIGNED_SIZE;
	xpc_vars = (struct xpc_vars *) next_cl;

	/*
	 * Before clearing xpc_vars, see if a page of AMOs had been previously
	 * allocated. If not we'll need to allocate one and set permissions
	 * so that cross-partition AMOs are allowed.
	 *
	 * The allocated AMO page needs MCA reporting to remain disabled after
	 * XPC has unloaded.  To make this work, we keep a copy of the pointer
	 * to this page (i.e., amos_page) in the struct xpc_vars structure,
	 * which is pointed to by the reserved page, and re-use that saved copy
	 * on subsequent loads of XPC. This AMO page is never freed, and its
	 * memory protections are never restricted.
	 */
	if ((amos_page = xpc_vars->amos_page) == NULL) {
		amos_page = (AMO_t *) mspec_kalloc_page(0);
		if (amos_page == NULL) {
			dev_err(xpc_part, "can't allocate page of AMOs\n");
			return NULL;
		}

		/*
		 * Open up AMO-R/W to cpu.  This is done for Shub 1.1 systems
		 * when xpc_allow_IPI_ops() is called via xpc_hb_init().
		 */
		if (!enable_shub_wars_1_1()) {
			ret = sn_change_memprotect(ia64_tpa((u64) amos_page),
					PAGE_SIZE, SN_MEMPROT_ACCESS_CLASS_1,
					&nasid_array);
			if (ret != 0) {
				dev_err(xpc_part, "can't change memory "
					"protections\n");
				mspec_kfree_page((unsigned long) amos_page);
				return NULL;
			}
		}
	} else if (!IS_AMO_ADDRESS((u64) amos_page)) {
		/*
		 * EFI's XPBOOT can also set amos_page in the reserved page,
		 * but it happens to leave it as an uncached physical address
		 * and we need it to be an uncached virtual, so we'll have to
		 * convert it.
		 */
		if (!IS_AMO_PHYS_ADDRESS((u64) amos_page)) {
			dev_err(xpc_part, "previously used amos_page address "
				"is bad = 0x%p\n", (void *) amos_page);
			return NULL;
		}
		amos_page = (AMO_t *) TO_AMO((u64) amos_page);
	}

	memset(xpc_vars, 0, sizeof(struct xpc_vars));

	/*
	 * Place the XPC per partition specific variables on the cache line
	 * following the XPC variables structure.
	 */
	next_cl += XPC_VARS_ALIGNED_SIZE;
	memset((u64 *) next_cl, 0, sizeof(struct xpc_vars_part) *
							XP_MAX_PARTITIONS);
	xpc_vars_part = (struct xpc_vars_part *) next_cl;
	xpc_vars->vars_part_pa = __pa(next_cl);

	xpc_vars->version = XPC_V_VERSION;
	xpc_vars->act_nasid = cpuid_to_nasid(0);
	xpc_vars->act_phys_cpuid = cpu_physical_id(0);
	xpc_vars->amos_page = amos_page;  /* save for next load of XPC */


	/*
	 * Initialize the activation related AMO variables.
	 */
	xpc_vars->act_amos = xpc_IPI_init(XP_MAX_PARTITIONS);
	for (i = 1; i < XP_NASID_MASK_WORDS; i++) {
		xpc_IPI_init(i + XP_MAX_PARTITIONS);
	}
	/* export AMO page's physical address to other partitions */
	xpc_vars->amos_page_pa = ia64_tpa((u64) xpc_vars->amos_page);

	/*
	 * This signifies to the remote partition that our reserved
	 * page is initialized.
	 */
	(volatile u64) rp->vars_pa = __pa(xpc_vars);

	return rp;
}


/*
 * Change protections to allow IPI operations (and AMO operations on
 * Shub 1.1 systems).
 */
void
xpc_allow_IPI_ops(void)
{
	int node;
	int nasid;


	// >>> Change SH_IPI_ACCESS code to use SAL call once it is available.

	if (is_shub2()) {
		xpc_sh2_IPI_access0 =
			(u64) HUB_L((u64 *) LOCAL_MMR_ADDR(SH2_IPI_ACCESS0));
		xpc_sh2_IPI_access1 =
			(u64) HUB_L((u64 *) LOCAL_MMR_ADDR(SH2_IPI_ACCESS1));
		xpc_sh2_IPI_access2 =
			(u64) HUB_L((u64 *) LOCAL_MMR_ADDR(SH2_IPI_ACCESS2));
		xpc_sh2_IPI_access3 =
			(u64) HUB_L((u64 *) LOCAL_MMR_ADDR(SH2_IPI_ACCESS3));

		for_each_online_node(node) {
			nasid = cnodeid_to_nasid(node);
			HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS0),
								-1UL);
			HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS1),
								-1UL);
			HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS2),
								-1UL);
			HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS3),
								-1UL);
		}

	} else {
		xpc_sh1_IPI_access =
			(u64) HUB_L((u64 *) LOCAL_MMR_ADDR(SH1_IPI_ACCESS));

		for_each_online_node(node) {
			nasid = cnodeid_to_nasid(node);
			HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH1_IPI_ACCESS),
								-1UL);

			/*
			 * Since the BIST collides with memory operations on
			 * SHUB 1.1 sn_change_memprotect() cannot be used.
			 */
			if (enable_shub_wars_1_1()) {
				/* open up everything */
				xpc_prot_vec[node] = (u64) HUB_L((u64 *)
						GLOBAL_MMR_ADDR(nasid,
						SH1_MD_DQLP_MMR_DIR_PRIVEC0));
				HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid,
						SH1_MD_DQLP_MMR_DIR_PRIVEC0),
								-1UL);
				HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid,
						SH1_MD_DQRP_MMR_DIR_PRIVEC0),
								-1UL);
			}
		}
	}
}


/*
 * Restrict protections to disallow IPI operations (and AMO operations on
 * Shub 1.1 systems).
 */
void
xpc_restrict_IPI_ops(void)
{
	int node;
	int nasid;


	// >>> Change SH_IPI_ACCESS code to use SAL call once it is available.

	if (is_shub2()) {

		for_each_online_node(node) {
			nasid = cnodeid_to_nasid(node);
			HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS0),
							xpc_sh2_IPI_access0);
			HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS1),
							xpc_sh2_IPI_access1);
			HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS2),
							xpc_sh2_IPI_access2);
			HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH2_IPI_ACCESS3),
							xpc_sh2_IPI_access3);
		}

	} else {

		for_each_online_node(node) {
			nasid = cnodeid_to_nasid(node);
			HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid, SH1_IPI_ACCESS),
							xpc_sh1_IPI_access);

			if (enable_shub_wars_1_1()) {
				HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid,
						SH1_MD_DQLP_MMR_DIR_PRIVEC0),
							xpc_prot_vec[node]);
				HUB_S((u64 *) GLOBAL_MMR_ADDR(nasid,
						SH1_MD_DQRP_MMR_DIR_PRIVEC0),
							xpc_prot_vec[node]);
			}
		}
	}
}


/*
 * At periodic intervals, scan through all active partitions and ensure
 * their heartbeat is still active.  If not, the partition is deactivated.
 */
void
xpc_check_remote_hb(void)
{
	struct xpc_vars *remote_vars;
	struct xpc_partition *part;
	partid_t partid;
	bte_result_t bres;


	remote_vars = (struct xpc_vars *) xpc_remote_copy_buffer;

	for (partid = 1; partid < XP_MAX_PARTITIONS; partid++) {
		if (partid == sn_partition_id) {
			continue;
		}

		part = &xpc_partitions[partid];

		if (part->act_state == XPC_P_INACTIVE ||
				part->act_state == XPC_P_DEACTIVATING) {
			continue;
		}

		/* pull the remote_hb cache line */
		bres = xp_bte_copy(part->remote_vars_pa,
					ia64_tpa((u64) remote_vars),
					XPC_VARS_ALIGNED_SIZE,
					(BTE_NOTIFY | BTE_WACQUIRE), NULL);
		if (bres != BTE_SUCCESS) {
			XPC_DEACTIVATE_PARTITION(part,
						xpc_map_bte_errors(bres));
			continue;
		}

		dev_dbg(xpc_part, "partid = %d, heartbeat = %ld, last_heartbeat"
			" = %ld, kdb_status = %ld, HB_mask = 0x%lx\n", partid,
			remote_vars->heartbeat, part->last_heartbeat,
			remote_vars->kdb_status,
			remote_vars->heartbeating_to_mask);

		if (((remote_vars->heartbeat == part->last_heartbeat) &&
			(remote_vars->kdb_status == 0)) ||
			     !XPC_HB_ALLOWED(sn_partition_id, remote_vars)) {

			XPC_DEACTIVATE_PARTITION(part, xpcNoHeartbeat);
			continue;
		}

		part->last_heartbeat = remote_vars->heartbeat;
	}
}


/*
 * Get a copy of the remote partition's rsvd page.
 *
 * remote_rp points to a buffer that is cacheline aligned for BTE copies and
 * assumed to be of size XPC_RSVD_PAGE_ALIGNED_SIZE.
 */
static enum xpc_retval
xpc_get_remote_rp(int nasid, u64 *discovered_nasids,
		struct xpc_rsvd_page *remote_rp, u64 *remote_rsvd_page_pa)
{
	int bres, i;


	/* get the reserved page's physical address */

	*remote_rsvd_page_pa = xpc_get_rsvd_page_pa(nasid, (u64) remote_rp,
						XPC_RSVD_PAGE_ALIGNED_SIZE);
	if (*remote_rsvd_page_pa == 0) {
		return xpcNoRsvdPageAddr;
	}


	/* pull over the reserved page structure */

	bres = xp_bte_copy(*remote_rsvd_page_pa, ia64_tpa((u64) remote_rp),
				XPC_RSVD_PAGE_ALIGNED_SIZE,
				(BTE_NOTIFY | BTE_WACQUIRE), NULL);
	if (bres != BTE_SUCCESS) {
		return xpc_map_bte_errors(bres);
	}


	if (discovered_nasids != NULL) {
		for (i = 0; i < XP_NASID_MASK_WORDS; i++) {
			discovered_nasids[i] |= remote_rp->part_nasids[i];
		}
	}


	/* check that the partid is for another partition */

	if (remote_rp->partid < 1 ||
				remote_rp->partid > (XP_MAX_PARTITIONS - 1)) {
		return xpcInvalidPartid;
	}

	if (remote_rp->partid == sn_partition_id) {
		return xpcLocalPartid;
	}


	if (XPC_VERSION_MAJOR(remote_rp->version) !=
					XPC_VERSION_MAJOR(XPC_RP_VERSION)) {
		return xpcBadVersion;
	}

	return xpcSuccess;
}


/*
 * Get a copy of the remote partition's XPC variables.
 *
 * remote_vars points to a buffer that is cacheline aligned for BTE copies and
 * assumed to be of size XPC_VARS_ALIGNED_SIZE.
 */
static enum xpc_retval
xpc_get_remote_vars(u64 remote_vars_pa, struct xpc_vars *remote_vars)
{
	int bres;


	if (remote_vars_pa == 0) {
		return xpcVarsNotSet;
	}


	/* pull over the cross partition variables */

	bres = xp_bte_copy(remote_vars_pa, ia64_tpa((u64) remote_vars),
				XPC_VARS_ALIGNED_SIZE,
				(BTE_NOTIFY | BTE_WACQUIRE), NULL);
	if (bres != BTE_SUCCESS) {
		return xpc_map_bte_errors(bres);
	}

	if (XPC_VERSION_MAJOR(remote_vars->version) !=
					XPC_VERSION_MAJOR(XPC_V_VERSION)) {
		return xpcBadVersion;
	}

	return xpcSuccess;
}


/*
 * Prior code has determine the nasid which generated an IPI.  Inspect
 * that nasid to determine if its partition needs to be activated or
 * deactivated.
 *
 * A partition is consider "awaiting activation" if our partition
 * flags indicate it is not active and it has a heartbeat.  A
 * partition is considered "awaiting deactivation" if our partition
 * flags indicate it is active but it has no heartbeat or it is not
 * sending its heartbeat to us.
 *
 * To determine the heartbeat, the remote nasid must have a properly
 * initialized reserved page.
 */
static void
xpc_identify_act_IRQ_req(int nasid)
{
	struct xpc_rsvd_page *remote_rp;
	struct xpc_vars *remote_vars;
	u64 remote_rsvd_page_pa;
	u64 remote_vars_pa;
	partid_t partid;
	struct xpc_partition *part;
	enum xpc_retval ret;


	/* pull over the reserved page structure */

	remote_rp = (struct xpc_rsvd_page *) xpc_remote_copy_buffer;

	ret = xpc_get_remote_rp(nasid, NULL, remote_rp, &remote_rsvd_page_pa);
	if (ret != xpcSuccess) {
		dev_warn(xpc_part, "unable to get reserved page from nasid %d, "
			"which sent interrupt, reason=%d\n", nasid, ret);
		return;
	}

	remote_vars_pa = remote_rp->vars_pa;
	partid = remote_rp->partid;
	part = &xpc_partitions[partid];


	/* pull over the cross partition variables */

	remote_vars = (struct xpc_vars *) xpc_remote_copy_buffer;

	ret = xpc_get_remote_vars(remote_vars_pa, remote_vars);
	if (ret != xpcSuccess) {

		dev_warn(xpc_part, "unable to get XPC variables from nasid %d, "
			"which sent interrupt, reason=%d\n", nasid, ret);

		XPC_DEACTIVATE_PARTITION(part, ret);
		return;
	}


	part->act_IRQ_rcvd++;

	dev_dbg(xpc_part, "partid for nasid %d is %d; IRQs = %d; HB = "
		"%ld:0x%lx\n", (int) nasid, (int) partid, part->act_IRQ_rcvd,
		remote_vars->heartbeat, remote_vars->heartbeating_to_mask);


	if (part->act_state == XPC_P_INACTIVE) {

		part->remote_rp_pa = remote_rsvd_page_pa;
		dev_dbg(xpc_part, "  remote_rp_pa = 0x%016lx\n",
			part->remote_rp_pa);

		part->remote_vars_pa = remote_vars_pa;
		dev_dbg(xpc_part, "  remote_vars_pa = 0x%016lx\n",
			part->remote_vars_pa);

		part->last_heartbeat = remote_vars->heartbeat;
		dev_dbg(xpc_part, "  last_heartbeat = 0x%016lx\n",
			part->last_heartbeat);

		part->remote_vars_part_pa = remote_vars->vars_part_pa;
		dev_dbg(xpc_part, "  remote_vars_part_pa = 0x%016lx\n",
			part->remote_vars_part_pa);

		part->remote_act_nasid = remote_vars->act_nasid;
		dev_dbg(xpc_part, "  remote_act_nasid = 0x%x\n",
			part->remote_act_nasid);

		part->remote_act_phys_cpuid = remote_vars->act_phys_cpuid;
		dev_dbg(xpc_part, "  remote_act_phys_cpuid = 0x%x\n",
			part->remote_act_phys_cpuid);

		part->remote_amos_page_pa = remote_vars->amos_page_pa;
		dev_dbg(xpc_part, "  remote_amos_page_pa = 0x%lx\n",
			part->remote_amos_page_pa);

		xpc_activate_partition(part);

	} else if (part->remote_amos_page_pa != remote_vars->amos_page_pa ||
			!XPC_HB_ALLOWED(sn_partition_id, remote_vars)) {

		part->reactivate_nasid = nasid;
		XPC_DEACTIVATE_PARTITION(part, xpcReactivating);
	}
}


/*
 * Loop through the activation AMO variables and process any bits
 * which are set.  Each bit indicates a nasid sending a partition
 * activation or deactivation request.
 *
 * Return #of IRQs detected.
 */
int
xpc_identify_act_IRQ_sender(void)
{
	int word, bit;
	u64 nasid_mask;
	u64 nasid;			/* remote nasid */
	int n_IRQs_detected = 0;
	AMO_t *act_amos;
	struct xpc_rsvd_page *rp = (struct xpc_rsvd_page *) xpc_rsvd_page;


	act_amos = xpc_vars->act_amos;


	/* scan through act AMO variable looking for non-zero entries */
	for (word = 0; word < XP_NASID_MASK_WORDS; word++) {

		nasid_mask = xpc_IPI_receive(&act_amos[word]);
		if (nasid_mask == 0) {
			/* no IRQs from nasids in this variable */
			continue;
		}

		dev_dbg(xpc_part, "AMO[%d] gave back 0x%lx\n", word,
			nasid_mask);


		/*
		 * If this nasid has been added to the machine since
		 * our partition was reset, this will retain the
		 * remote nasid in our reserved pages machine mask.
		 * This is used in the event of module reload.
		 */
		rp->mach_nasids[word] |= nasid_mask;


		/* locate the nasid(s) which sent interrupts */

		for (bit = 0; bit < (8 * sizeof(u64)); bit++) {
			if (nasid_mask & (1UL << bit)) {
				n_IRQs_detected++;
				nasid = XPC_NASID_FROM_W_B(word, bit);
				dev_dbg(xpc_part, "interrupt from nasid %ld\n",
					nasid);
				xpc_identify_act_IRQ_req(nasid);
			}
		}
	}
	return n_IRQs_detected;
}


/*
 * Mark specified partition as active.
 */
enum xpc_retval
xpc_mark_partition_active(struct xpc_partition *part)
{
	unsigned long irq_flags;
	enum xpc_retval ret;


	dev_dbg(xpc_part, "setting partition %d to ACTIVE\n", XPC_PARTID(part));

	spin_lock_irqsave(&part->act_lock, irq_flags);
	if (part->act_state == XPC_P_ACTIVATING) {
		part->act_state = XPC_P_ACTIVE;
		ret = xpcSuccess;
	} else {
		DBUG_ON(part->reason == xpcSuccess);
		ret = part->reason;
	}
	spin_unlock_irqrestore(&part->act_lock, irq_flags);

	return ret;
}


/*
 * Notify XPC that the partition is down.
 */
void
xpc_deactivate_partition(const int line, struct xpc_partition *part,
				enum xpc_retval reason)
{
	unsigned long irq_flags;
	partid_t partid = XPC_PARTID(part);


	spin_lock_irqsave(&part->act_lock, irq_flags);

	if (part->act_state == XPC_P_INACTIVE) {
		XPC_SET_REASON(part, reason, line);
		spin_unlock_irqrestore(&part->act_lock, irq_flags);
		if (reason == xpcReactivating) {
			/* we interrupt ourselves to reactivate partition */
			xpc_IPI_send_reactivate(part);
		}
		return;
	}
	if (part->act_state == XPC_P_DEACTIVATING) {
		if ((part->reason == xpcUnloading && reason != xpcUnloading) ||
					reason == xpcReactivating) {
			XPC_SET_REASON(part, reason, line);
		}
		spin_unlock_irqrestore(&part->act_lock, irq_flags);
		return;
	}

	part->act_state = XPC_P_DEACTIVATING;
	XPC_SET_REASON(part, reason, line);

	spin_unlock_irqrestore(&part->act_lock, irq_flags);

	XPC_DISALLOW_HB(partid, xpc_vars);

	dev_dbg(xpc_part, "bringing partition %d down, reason = %d\n", partid,
		reason);

	xpc_partition_down(part, reason);
}


/*
 * Mark specified partition as active.
 */
void
xpc_mark_partition_inactive(struct xpc_partition *part)
{
	unsigned long irq_flags;


	dev_dbg(xpc_part, "setting partition %d to INACTIVE\n",
		XPC_PARTID(part));

	spin_lock_irqsave(&part->act_lock, irq_flags);
	part->act_state = XPC_P_INACTIVE;
	spin_unlock_irqrestore(&part->act_lock, irq_flags);
	part->remote_rp_pa = 0;
}


/*
 * SAL has provided a partition and machine mask.  The partition mask
 * contains a bit for each even nasid in our partition.  The machine
 * mask contains a bit for each even nasid in the entire machine.
 *
 * Using those two bit arrays, we can determine which nasids are
 * known in the machine.  Each should also have a reserved page
 * initialized if they are available for partitioning.
 */
void
xpc_discovery(void)
{
	void *remote_rp_base;
	struct xpc_rsvd_page *remote_rp;
	struct xpc_vars *remote_vars;
	u64 remote_rsvd_page_pa;
	u64 remote_vars_pa;
	int region;
	int max_regions;
	int nasid;
	struct xpc_rsvd_page *rp;
	partid_t partid;
	struct xpc_partition *part;
	u64 *discovered_nasids;
	enum xpc_retval ret;


	remote_rp = xpc_kmalloc_cacheline_aligned(XPC_RSVD_PAGE_ALIGNED_SIZE,
						GFP_KERNEL, &remote_rp_base);
	if (remote_rp == NULL) {
		return;
	}
	remote_vars = (struct xpc_vars *) remote_rp;


	discovered_nasids = kmalloc(sizeof(u64) * XP_NASID_MASK_WORDS,
							GFP_KERNEL);
	if (discovered_nasids == NULL) {
		kfree(remote_rp_base);
		return;
	}
	memset(discovered_nasids, 0, sizeof(u64) * XP_NASID_MASK_WORDS);

	rp = (struct xpc_rsvd_page *) xpc_rsvd_page;

	/*
	 * The term 'region' in this context refers to the minimum number of
	 * nodes that can comprise an access protection grouping. The access
	 * protection is in regards to memory, IOI and IPI.
	 */
//>>> move the next two #defines into either include/asm-ia64/sn/arch.h or
//>>> include/asm-ia64/sn/addrs.h
#define SH1_MAX_REGIONS		64
#define SH2_MAX_REGIONS		256
	max_regions = is_shub2() ? SH2_MAX_REGIONS : SH1_MAX_REGIONS;

	for (region = 0; region < max_regions; region++) {

		if ((volatile int) xpc_exiting) {
			break;
		}

		dev_dbg(xpc_part, "searching region %d\n", region);

		for (nasid = (region * sn_region_size * 2);
		     nasid < ((region + 1) * sn_region_size * 2);
		     nasid += 2) {

			if ((volatile int) xpc_exiting) {
				break;
			}

			dev_dbg(xpc_part, "checking nasid %d\n", nasid);


			if (XPC_NASID_IN_ARRAY(nasid, rp->part_nasids)) {
				dev_dbg(xpc_part, "PROM indicates Nasid %d is "
					"part of the local partition; skipping "
					"region\n", nasid);
				break;
			}

			if (!(XPC_NASID_IN_ARRAY(nasid, rp->mach_nasids))) {
				dev_dbg(xpc_part, "PROM indicates Nasid %d was "
					"not on Numa-Link network at reset\n",
					nasid);
				continue;
			}

			if (XPC_NASID_IN_ARRAY(nasid, discovered_nasids)) {
				dev_dbg(xpc_part, "Nasid %d is part of a "
					"partition which was previously "
					"discovered\n", nasid);
				continue;
			}


			/* pull over the reserved page structure */

			ret = xpc_get_remote_rp(nasid, discovered_nasids,
					      remote_rp, &remote_rsvd_page_pa);
			if (ret != xpcSuccess) {
				dev_dbg(xpc_part, "unable to get reserved page "
					"from nasid %d, reason=%d\n", nasid,
					ret);

				if (ret == xpcLocalPartid) {
					break;
				}
				continue;
			}

			remote_vars_pa = remote_rp->vars_pa;

			partid = remote_rp->partid;
			part = &xpc_partitions[partid];


			/* pull over the cross partition variables */

			ret = xpc_get_remote_vars(remote_vars_pa, remote_vars);
			if (ret != xpcSuccess) {
				dev_dbg(xpc_part, "unable to get XPC variables "
					"from nasid %d, reason=%d\n", nasid,
					ret);

				XPC_DEACTIVATE_PARTITION(part, ret);
				continue;
			}

			if (part->act_state != XPC_P_INACTIVE) {
				dev_dbg(xpc_part, "partition %d on nasid %d is "
					"already activating\n", partid, nasid);
				break;
			}

			/*
			 * Register the remote partition's AMOs with SAL so it
			 * can handle and cleanup errors within that address
			 * range should the remote partition go down. We don't
			 * unregister this range because it is difficult to
			 * tell when outstanding writes to the remote partition
			 * are finished and thus when it is thus safe to
			 * unregister. This should not result in wasted space
			 * in the SAL xp_addr_region table because we should
			 * get the same page for remote_act_amos_pa after
			 * module reloads and system reboots.
			 */
			if (sn_register_xp_addr_region(
					    remote_vars->amos_page_pa,
							PAGE_SIZE, 1) < 0) {
				dev_dbg(xpc_part, "partition %d failed to "
					"register xp_addr region 0x%016lx\n",
					partid, remote_vars->amos_page_pa);

				XPC_SET_REASON(part, xpcPhysAddrRegFailed,
						__LINE__);
				break;
			}

			/*
			 * The remote nasid is valid and available.
			 * Send an interrupt to that nasid to notify
			 * it that we are ready to begin activation.
			 */
			dev_dbg(xpc_part, "sending an interrupt to AMO 0x%lx, "
				"nasid %d, phys_cpuid 0x%x\n",
				remote_vars->amos_page_pa,
				remote_vars->act_nasid,
				remote_vars->act_phys_cpuid);

			xpc_IPI_send_activate(remote_vars);
		}
	}

	kfree(discovered_nasids);
	kfree(remote_rp_base);
}


/*
 * Given a partid, get the nasids owned by that partition from the
 * remote partition's reserved page.
 */
enum xpc_retval
xpc_initiate_partid_to_nasids(partid_t partid, void *nasid_mask)
{
	struct xpc_partition *part;
	u64 part_nasid_pa;
	int bte_res;


	part = &xpc_partitions[partid];
	if (part->remote_rp_pa == 0) {
		return xpcPartitionDown;
	}

	part_nasid_pa = part->remote_rp_pa +
		(u64) &((struct xpc_rsvd_page *) 0)->part_nasids;

	bte_res = xp_bte_copy(part_nasid_pa, ia64_tpa((u64) nasid_mask),
				L1_CACHE_ALIGN(XP_NASID_MASK_BYTES),
				(BTE_NOTIFY | BTE_WACQUIRE), NULL);

	return xpc_map_bte_errors(bte_res);
}