summaryrefslogtreecommitdiffstats
path: root/drivers/misc/sgi-gru/grumain.c
blob: 347004e4f591c870e404e58f3133ec44b3de1520 (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
/*
 * SN Platform GRU Driver
 *
 *            DRIVER TABLE MANAGER + GRU CONTEXT LOAD/UNLOAD
 *
 * 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) 2008 Silicon Graphics, Inc.  All Rights Reserved.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/list.h>
#include <asm/uv/uv_hub.h>
#include "gru.h"
#include "grutables.h"
#include "gruhandles.h"

unsigned long gru_options __read_mostly;

static struct device_driver gru_driver = {
	.name = "gru"
};

static struct device gru_device = {
	.init_name = "",
	.driver = &gru_driver,
};

struct device *grudev = &gru_device;

/*
 * Select a gru fault map to be used by the current cpu. Note that
 * multiple cpus may be using the same map.
 *	ZZZ should "shift" be used?? Depends on HT cpu numbering
 *	ZZZ should be inline but did not work on emulator
 */
int gru_cpu_fault_map_id(void)
{
	return uv_blade_processor_id() % GRU_NUM_TFM;
}

/*--------- ASID Management -------------------------------------------
 *
 *  Initially, assign asids sequentially from MIN_ASID .. MAX_ASID.
 *  Once MAX is reached, flush the TLB & start over. However,
 *  some asids may still be in use. There won't be many (percentage wise) still
 *  in use. Search active contexts & determine the value of the first
 *  asid in use ("x"s below). Set "limit" to this value.
 *  This defines a block of assignable asids.
 *
 *  When "limit" is reached, search forward from limit+1 and determine the
 *  next block of assignable asids.
 *
 *  Repeat until MAX_ASID is reached, then start over again.
 *
 *  Each time MAX_ASID is reached, increment the asid generation. Since
 *  the search for in-use asids only checks contexts with GRUs currently
 *  assigned, asids in some contexts will be missed. Prior to loading
 *  a context, the asid generation of the GTS asid is rechecked. If it
 *  doesn't match the current generation, a new asid will be assigned.
 *
 *   	0---------------x------------x---------------------x----|
 *	  ^-next	^-limit	   				^-MAX_ASID
 *
 * All asid manipulation & context loading/unloading is protected by the
 * gs_lock.
 */

/* Hit the asid limit. Start over */
static int gru_wrap_asid(struct gru_state *gru)
{
	gru_dbg(grudev, "gid %d\n", gru->gs_gid);
	STAT(asid_wrap);
	gru->gs_asid_gen++;
	return MIN_ASID;
}

/* Find the next chunk of unused asids */
static int gru_reset_asid_limit(struct gru_state *gru, int asid)
{
	int i, gid, inuse_asid, limit;

	gru_dbg(grudev, "gid %d, asid 0x%x\n", gru->gs_gid, asid);
	STAT(asid_next);
	limit = MAX_ASID;
	if (asid >= limit)
		asid = gru_wrap_asid(gru);
	gru_flush_all_tlb(gru);
	gid = gru->gs_gid;
again:
	for (i = 0; i < GRU_NUM_CCH; i++) {
		if (!gru->gs_gts[i] || is_kernel_context(gru->gs_gts[i]))
			continue;
		inuse_asid = gru->gs_gts[i]->ts_gms->ms_asids[gid].mt_asid;
		gru_dbg(grudev, "gid %d, gts %p, gms %p, inuse 0x%x, cxt %d\n",
			gru->gs_gid, gru->gs_gts[i], gru->gs_gts[i]->ts_gms,
			inuse_asid, i);
		if (inuse_asid == asid) {
			asid += ASID_INC;
			if (asid >= limit) {
				/*
				 * empty range: reset the range limit and
				 * start over
				 */
				limit = MAX_ASID;
				if (asid >= MAX_ASID)
					asid = gru_wrap_asid(gru);
				goto again;
			}
		}

		if ((inuse_asid > asid) && (inuse_asid < limit))
			limit = inuse_asid;
	}
	gru->gs_asid_limit = limit;
	gru->gs_asid = asid;
	gru_dbg(grudev, "gid %d, new asid 0x%x, new_limit 0x%x\n", gru->gs_gid,
					asid, limit);
	return asid;
}

/* Assign a new ASID to a thread context.  */
static int gru_assign_asid(struct gru_state *gru)
{
	int asid;

	gru->gs_asid += ASID_INC;
	asid = gru->gs_asid;
	if (asid >= gru->gs_asid_limit)
		asid = gru_reset_asid_limit(gru, asid);

	gru_dbg(grudev, "gid %d, asid 0x%x\n", gru->gs_gid, asid);
	return asid;
}

/*
 * Clear n bits in a word. Return a word indicating the bits that were cleared.
 * Optionally, build an array of chars that contain the bit numbers allocated.
 */
static unsigned long reserve_resources(unsigned long *p, int n, int mmax,
				       char *idx)
{
	unsigned long bits = 0;
	int i;

	while (n--) {
		i = find_first_bit(p, mmax);
		if (i == mmax)
			BUG();
		__clear_bit(i, p);
		__set_bit(i, &bits);
		if (idx)
			*idx++ = i;
	}
	return bits;
}

unsigned long gru_reserve_cb_resources(struct gru_state *gru, int cbr_au_count,
				       char *cbmap)
{
	return reserve_resources(&gru->gs_cbr_map, cbr_au_count, GRU_CBR_AU,
				 cbmap);
}

unsigned long gru_reserve_ds_resources(struct gru_state *gru, int dsr_au_count,
				       char *dsmap)
{
	return reserve_resources(&gru->gs_dsr_map, dsr_au_count, GRU_DSR_AU,
				 dsmap);
}

static void reserve_gru_resources(struct gru_state *gru,
				  struct gru_thread_state *gts)
{
	gru->gs_active_contexts++;
	gts->ts_cbr_map =
	    gru_reserve_cb_resources(gru, gts->ts_cbr_au_count,
				     gts->ts_cbr_idx);
	gts->ts_dsr_map =
	    gru_reserve_ds_resources(gru, gts->ts_dsr_au_count, NULL);
}

static void free_gru_resources(struct gru_state *gru,
			       struct gru_thread_state *gts)
{
	gru->gs_active_contexts--;
	gru->gs_cbr_map |= gts->ts_cbr_map;
	gru->gs_dsr_map |= gts->ts_dsr_map;
}

/*
 * Check if a GRU has sufficient free resources to satisfy an allocation
 * request. Note: GRU locks may or may not be held when this is called. If
 * not held, recheck after acquiring the appropriate locks.
 *
 * Returns 1 if sufficient resources, 0 if not
 */
static int check_gru_resources(struct gru_state *gru, int cbr_au_count,
			       int dsr_au_count, int max_active_contexts)
{
	return hweight64(gru->gs_cbr_map) >= cbr_au_count
		&& hweight64(gru->gs_dsr_map) >= dsr_au_count
		&& gru->gs_active_contexts < max_active_contexts;
}

/*
 * TLB manangment requires tracking all GRU chiplets that have loaded a GSEG
 * context.
 */
static int gru_load_mm_tracker(struct gru_state *gru,
					struct gru_thread_state *gts)
{
	struct gru_mm_struct *gms = gts->ts_gms;
	struct gru_mm_tracker *asids = &gms->ms_asids[gru->gs_gid];
	unsigned short ctxbitmap = (1 << gts->ts_ctxnum);
	int asid;

	spin_lock(&gms->ms_asid_lock);
	asid = asids->mt_asid;

	spin_lock(&gru->gs_asid_lock);
	if (asid == 0 || (asids->mt_ctxbitmap == 0 && asids->mt_asid_gen !=
			  gru->gs_asid_gen)) {
		asid = gru_assign_asid(gru);
		asids->mt_asid = asid;
		asids->mt_asid_gen = gru->gs_asid_gen;
		STAT(asid_new);
	} else {
		STAT(asid_reuse);
	}
	spin_unlock(&gru->gs_asid_lock);

	BUG_ON(asids->mt_ctxbitmap & ctxbitmap);
	asids->mt_ctxbitmap |= ctxbitmap;
	if (!test_bit(gru->gs_gid, gms->ms_asidmap))
		__set_bit(gru->gs_gid, gms->ms_asidmap);
	spin_unlock(&gms->ms_asid_lock);

	gru_dbg(grudev,
		"gid %d, gts %p, gms %p, ctxnum %d, asid 0x%x, asidmap 0x%lx\n",
		gru->gs_gid, gts, gms, gts->ts_ctxnum, asid,
		gms->ms_asidmap[0]);
	return asid;
}

static void gru_unload_mm_tracker(struct gru_state *gru,
					struct gru_thread_state *gts)
{
	struct gru_mm_struct *gms = gts->ts_gms;
	struct gru_mm_tracker *asids;
	unsigned short ctxbitmap;

	asids = &gms->ms_asids[gru->gs_gid];
	ctxbitmap = (1 << gts->ts_ctxnum);
	spin_lock(&gms->ms_asid_lock);
	spin_lock(&gru->gs_asid_lock);
	BUG_ON((asids->mt_ctxbitmap & ctxbitmap) != ctxbitmap);
	asids->mt_ctxbitmap ^= ctxbitmap;
	gru_dbg(grudev, "gid %d, gts %p, gms %p, ctxnum 0x%d, asidmap 0x%lx\n",
		gru->gs_gid, gts, gms, gts->ts_ctxnum, gms->ms_asidmap[0]);
	spin_unlock(&gru->gs_asid_lock);
	spin_unlock(&gms->ms_asid_lock);
}

/*
 * Decrement the reference count on a GTS structure. Free the structure
 * if the reference count goes to zero.
 */
void gts_drop(struct gru_thread_state *gts)
{
	if (gts && atomic_dec_return(&gts->ts_refcnt) == 0) {
		gru_drop_mmu_notifier(gts->ts_gms);
		kfree(gts);
		STAT(gts_free);
	}
}

/*
 * Locate the GTS structure for the current thread.
 */
static struct gru_thread_state *gru_find_current_gts_nolock(struct gru_vma_data
			    *vdata, int tsid)
{
	struct gru_thread_state *gts;

	list_for_each_entry(gts, &vdata->vd_head, ts_next)
	    if (gts->ts_tsid == tsid)
		return gts;
	return NULL;
}

/*
 * Allocate a thread state structure.
 */
struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma,
		int cbr_au_count, int dsr_au_count, int options, int tsid)
{
	struct gru_thread_state *gts;
	int bytes;

	bytes = DSR_BYTES(dsr_au_count) + CBR_BYTES(cbr_au_count);
	bytes += sizeof(struct gru_thread_state);
	gts = kmalloc(bytes, GFP_KERNEL);
	if (!gts)
		return NULL;

	STAT(gts_alloc);
	memset(gts, 0, sizeof(struct gru_thread_state)); /* zero out header */
	atomic_set(&gts->ts_refcnt, 1);
	mutex_init(&gts->ts_ctxlock);
	gts->ts_cbr_au_count = cbr_au_count;
	gts->ts_dsr_au_count = dsr_au_count;
	gts->ts_user_options = options;
	gts->ts_tsid = tsid;
	gts->ts_ctxnum = NULLCTX;
	gts->ts_tlb_int_select = -1;
	gts->ts_sizeavail = GRU_SIZEAVAIL(PAGE_SHIFT);
	if (vma) {
		gts->ts_mm = current->mm;
		gts->ts_vma = vma;
		gts->ts_gms = gru_register_mmu_notifier();
		if (!gts->ts_gms)
			goto err;
	}

	gru_dbg(grudev, "alloc gts %p\n", gts);
	return gts;

err:
	gts_drop(gts);
	return NULL;
}

/*
 * Allocate a vma private data structure.
 */
struct gru_vma_data *gru_alloc_vma_data(struct vm_area_struct *vma, int tsid)
{
	struct gru_vma_data *vdata = NULL;

	vdata = kmalloc(sizeof(*vdata), GFP_KERNEL);
	if (!vdata)
		return NULL;

	INIT_LIST_HEAD(&vdata->vd_head);
	spin_lock_init(&vdata->vd_lock);
	gru_dbg(grudev, "alloc vdata %p\n", vdata);
	return vdata;
}

/*
 * Find the thread state structure for the current thread.
 */
struct gru_thread_state *gru_find_thread_state(struct vm_area_struct *vma,
					int tsid)
{
	struct gru_vma_data *vdata = vma->vm_private_data;
	struct gru_thread_state *gts;

	spin_lock(&vdata->vd_lock);
	gts = gru_find_current_gts_nolock(vdata, tsid);
	spin_unlock(&vdata->vd_lock);
	gru_dbg(grudev, "vma %p, gts %p\n", vma, gts);
	return gts;
}

/*
 * Allocate a new thread state for a GSEG. Note that races may allow
 * another thread to race to create a gts.
 */
struct gru_thread_state *gru_alloc_thread_state(struct vm_area_struct *vma,
					int tsid)
{
	struct gru_vma_data *vdata = vma->vm_private_data;
	struct gru_thread_state *gts, *ngts;

	gts = gru_alloc_gts(vma, vdata->vd_cbr_au_count, vdata->vd_dsr_au_count,
			    vdata->vd_user_options, tsid);
	if (!gts)
		return NULL;

	spin_lock(&vdata->vd_lock);
	ngts = gru_find_current_gts_nolock(vdata, tsid);
	if (ngts) {
		gts_drop(gts);
		gts = ngts;
		STAT(gts_double_allocate);
	} else {
		list_add(&gts->ts_next, &vdata->vd_head);
	}
	spin_unlock(&vdata->vd_lock);
	gru_dbg(grudev, "vma %p, gts %p\n", vma, gts);
	return gts;
}

/*
 * Free the GRU context assigned to the thread state.
 */
static void gru_free_gru_context(struct gru_thread_state *gts)
{
	struct gru_state *gru;

	gru = gts->ts_gru;
	gru_dbg(grudev, "gts %p, gid %d\n", gts, gru->gs_gid);

	spin_lock(&gru->gs_lock);
	gru->gs_gts[gts->ts_ctxnum] = NULL;
	free_gru_resources(gru, gts);
	BUG_ON(test_bit(gts->ts_ctxnum, &gru->gs_context_map) == 0);
	__clear_bit(gts->ts_ctxnum, &gru->gs_context_map);
	gts->ts_ctxnum = NULLCTX;
	gts->ts_gru = NULL;
	gts->ts_blade = -1;
	spin_unlock(&gru->gs_lock);

	gts_drop(gts);
	STAT(free_context);
}

/*
 * Prefetching cachelines help hardware performance.
 * (Strictly a performance enhancement. Not functionally required).
 */
static void prefetch_data(void *p, int num, int stride)
{
	while (num-- > 0) {
		prefetchw(p);
		p += stride;
	}
}

static inline long gru_copy_handle(void *d, void *s)
{
	memcpy(d, s, GRU_HANDLE_BYTES);
	return GRU_HANDLE_BYTES;
}

static void gru_prefetch_context(void *gseg, void *cb, void *cbe,
				unsigned long cbrmap, unsigned long length)
{
	int i, scr;

	prefetch_data(gseg + GRU_DS_BASE, length / GRU_CACHE_LINE_BYTES,
		      GRU_CACHE_LINE_BYTES);

	for_each_cbr_in_allocation_map(i, &cbrmap, scr) {
		prefetch_data(cb, 1, GRU_CACHE_LINE_BYTES);
		prefetch_data(cbe + i * GRU_HANDLE_STRIDE, 1,
			      GRU_CACHE_LINE_BYTES);
		cb += GRU_HANDLE_STRIDE;
	}
}

static void gru_load_context_data(void *save, void *grubase, int ctxnum,
				  unsigned long cbrmap, unsigned long dsrmap,
				  int data_valid)
{
	void *gseg, *cb, *cbe;
	unsigned long length;
	int i, scr;

	gseg = grubase + ctxnum * GRU_GSEG_STRIDE;
	cb = gseg + GRU_CB_BASE;
	cbe = grubase + GRU_CBE_BASE;
	length = hweight64(dsrmap) * GRU_DSR_AU_BYTES;
	gru_prefetch_context(gseg, cb, cbe, cbrmap, length);

	for_each_cbr_in_allocation_map(i, &cbrmap, scr) {
		if (data_valid) {
			save += gru_copy_handle(cb, save);
			save += gru_copy_handle(cbe + i * GRU_HANDLE_STRIDE,
						save);
		} else {
			memset(cb, 0, GRU_CACHE_LINE_BYTES);
			memset(cbe + i * GRU_HANDLE_STRIDE, 0,
						GRU_CACHE_LINE_BYTES);
		}
		cb += GRU_HANDLE_STRIDE;
	}

	if (data_valid)
		memcpy(gseg + GRU_DS_BASE, save, length);
	else
		memset(gseg + GRU_DS_BASE, 0, length);
}

static void gru_unload_context_data(void *save, void *grubase, int ctxnum,
				    unsigned long cbrmap, unsigned long dsrmap)
{
	void *gseg, *cb, *cbe;
	unsigned long length;
	int i, scr;

	gseg = grubase + ctxnum * GRU_GSEG_STRIDE;
	cb = gseg + GRU_CB_BASE;
	cbe = grubase + GRU_CBE_BASE;
	length = hweight64(dsrmap) * GRU_DSR_AU_BYTES;
	gru_prefetch_context(gseg, cb, cbe, cbrmap, length);

	for_each_cbr_in_allocation_map(i, &cbrmap, scr) {
		save += gru_copy_handle(save, cb);
		save += gru_copy_handle(save, cbe + i * GRU_HANDLE_STRIDE);
		cb += GRU_HANDLE_STRIDE;
	}
	memcpy(save, gseg + GRU_DS_BASE, length);
}

void gru_unload_context(struct gru_thread_state *gts, int savestate)
{
	struct gru_state *gru = gts->ts_gru;
	struct gru_context_configuration_handle *cch;
	int ctxnum = gts->ts_ctxnum;

	if (!is_kernel_context(gts))
		zap_vma_ptes(gts->ts_vma, UGRUADDR(gts), GRU_GSEG_PAGESIZE);
	cch = get_cch(gru->gs_gru_base_vaddr, ctxnum);

	gru_dbg(grudev, "gts %p\n", gts);
	lock_cch_handle(cch);
	if (cch_interrupt_sync(cch))
		BUG();

	if (!is_kernel_context(gts))
		gru_unload_mm_tracker(gru, gts);
	if (savestate) {
		gru_unload_context_data(gts->ts_gdata, gru->gs_gru_base_vaddr,
					ctxnum, gts->ts_cbr_map,
					gts->ts_dsr_map);
		gts->ts_data_valid = 1;
	}

	if (cch_deallocate(cch))
		BUG();
	gts->ts_force_unload = 0;	/* ts_force_unload locked by CCH lock */
	unlock_cch_handle(cch);

	gru_free_gru_context(gts);
}

/*
 * Load a GRU context by copying it from the thread data structure in memory
 * to the GRU.
 */
void gru_load_context(struct gru_thread_state *gts)
{
	struct gru_state *gru = gts->ts_gru;
	struct gru_context_configuration_handle *cch;
	int i, err, asid, ctxnum = gts->ts_ctxnum;

	gru_dbg(grudev, "gts %p\n", gts);
	cch = get_cch(gru->gs_gru_base_vaddr, ctxnum);

	lock_cch_handle(cch);
	cch->tfm_fault_bit_enable =
	    (gts->ts_user_options == GRU_OPT_MISS_FMM_POLL
	     || gts->ts_user_options == GRU_OPT_MISS_FMM_INTR);
	cch->tlb_int_enable = (gts->ts_user_options == GRU_OPT_MISS_FMM_INTR);
	if (cch->tlb_int_enable) {
		gts->ts_tlb_int_select = gru_cpu_fault_map_id();
		cch->tlb_int_select = gts->ts_tlb_int_select;
	}
	cch->tfm_done_bit_enable = 0;
	cch->dsr_allocation_map = gts->ts_dsr_map;
	cch->cbr_allocation_map = gts->ts_cbr_map;

	if (is_kernel_context(gts)) {
		cch->unmap_enable = 1;
		cch->tfm_done_bit_enable = 1;
		cch->cb_int_enable = 1;
	} else {
		cch->unmap_enable = 0;
		cch->tfm_done_bit_enable = 0;
		cch->cb_int_enable = 0;
		asid = gru_load_mm_tracker(gru, gts);
		for (i = 0; i < 8; i++) {
			cch->asid[i] = asid + i;
			cch->sizeavail[i] = gts->ts_sizeavail;
		}
	}

	err = cch_allocate(cch);
	if (err) {
		gru_dbg(grudev,
			"err %d: cch %p, gts %p, cbr 0x%lx, dsr 0x%lx\n",
			err, cch, gts, gts->ts_cbr_map, gts->ts_dsr_map);
		BUG();
	}

	gru_load_context_data(gts->ts_gdata, gru->gs_gru_base_vaddr, ctxnum,
			gts->ts_cbr_map, gts->ts_dsr_map, gts->ts_data_valid);

	if (cch_start(cch))
		BUG();
	unlock_cch_handle(cch);
}

/*
 * Update fields in an active CCH:
 * 	- retarget interrupts on local blade
 * 	- update sizeavail mask
 * 	- force a delayed context unload by clearing the CCH asids. This
 * 	  forces TLB misses for new GRU instructions. The context is unloaded
 * 	  when the next TLB miss occurs.
 */
int gru_update_cch(struct gru_thread_state *gts, int force_unload)
{
	struct gru_context_configuration_handle *cch;
	struct gru_state *gru = gts->ts_gru;
	int i, ctxnum = gts->ts_ctxnum, ret = 0;

	cch = get_cch(gru->gs_gru_base_vaddr, ctxnum);

	lock_cch_handle(cch);
	if (cch->state == CCHSTATE_ACTIVE) {
		if (gru->gs_gts[gts->ts_ctxnum] != gts)
			goto exit;
		if (cch_interrupt(cch))
			BUG();
		if (!force_unload) {
			for (i = 0; i < 8; i++)
				cch->sizeavail[i] = gts->ts_sizeavail;
			gts->ts_tlb_int_select = gru_cpu_fault_map_id();
			cch->tlb_int_select = gru_cpu_fault_map_id();
			cch->tfm_fault_bit_enable =
			  (gts->ts_user_options == GRU_OPT_MISS_FMM_POLL
			    || gts->ts_user_options == GRU_OPT_MISS_FMM_INTR);
		} else {
			for (i = 0; i < 8; i++)
				cch->asid[i] = 0;
			cch->tfm_fault_bit_enable = 0;
			cch->tlb_int_enable = 0;
			gts->ts_force_unload = 1;
		}
		if (cch_start(cch))
			BUG();
		ret = 1;
	}
exit:
	unlock_cch_handle(cch);
	return ret;
}

/*
 * Update CCH tlb interrupt select. Required when all the following is true:
 * 	- task's GRU context is loaded into a GRU
 * 	- task is using interrupt notification for TLB faults
 * 	- task has migrated to a different cpu on the same blade where
 * 	  it was previously running.
 */
static int gru_retarget_intr(struct gru_thread_state *gts)
{
	if (gts->ts_tlb_int_select < 0
	    || gts->ts_tlb_int_select == gru_cpu_fault_map_id())
		return 0;

	gru_dbg(grudev, "retarget from %d to %d\n", gts->ts_tlb_int_select,
		gru_cpu_fault_map_id());
	return gru_update_cch(gts, 0);
}


/*
 * Insufficient GRU resources available on the local blade. Steal a context from
 * a process. This is a hack until a _real_ resource scheduler is written....
 */
#define next_ctxnum(n)	((n) <  GRU_NUM_CCH - 2 ? (n) + 1 : 0)
#define next_gru(b, g)	(((g) < &(b)->bs_grus[GRU_CHIPLETS_PER_BLADE - 1]) ?  \
				 ((g)+1) : &(b)->bs_grus[0])

static int is_gts_stealable(struct gru_thread_state *gts,
		struct gru_blade_state *bs)
{
	if (is_kernel_context(gts))
		return down_write_trylock(&bs->bs_kgts_sema);
	else
		return mutex_trylock(&gts->ts_ctxlock);
}

static void gts_stolen(struct gru_thread_state *gts,
		struct gru_blade_state *bs)
{
	if (is_kernel_context(gts)) {
		up_write(&bs->bs_kgts_sema);
		STAT(steal_kernel_context);
	} else {
		mutex_unlock(&gts->ts_ctxlock);
		STAT(steal_user_context);
	}
}

void gru_steal_context(struct gru_thread_state *gts, int blade_id)
{
	struct gru_blade_state *blade;
	struct gru_state *gru, *gru0;
	struct gru_thread_state *ngts = NULL;
	int ctxnum, ctxnum0, flag = 0, cbr, dsr;

	cbr = gts->ts_cbr_au_count;
	dsr = gts->ts_dsr_au_count;

	blade = gru_base[blade_id];
	spin_lock(&blade->bs_lock);

	ctxnum = next_ctxnum(blade->bs_lru_ctxnum);
	gru = blade->bs_lru_gru;
	if (ctxnum == 0)
		gru = next_gru(blade, gru);
	ctxnum0 = ctxnum;
	gru0 = gru;
	while (1) {
		if (check_gru_resources(gru, cbr, dsr, GRU_NUM_CCH))
			break;
		spin_lock(&gru->gs_lock);
		for (; ctxnum < GRU_NUM_CCH; ctxnum++) {
			if (flag && gru == gru0 && ctxnum == ctxnum0)
				break;
			ngts = gru->gs_gts[ctxnum];
			/*
			 * We are grabbing locks out of order, so trylock is
			 * needed. GTSs are usually not locked, so the odds of
			 * success are high. If trylock fails, try to steal a
			 * different GSEG.
			 */
			if (ngts && is_gts_stealable(ngts, blade))
				break;
			ngts = NULL;
			flag = 1;
		}
		spin_unlock(&gru->gs_lock);
		if (ngts || (flag && gru == gru0 && ctxnum == ctxnum0))
			break;
		ctxnum = 0;
		gru = next_gru(blade, gru);
	}
	blade->bs_lru_gru = gru;
	blade->bs_lru_ctxnum = ctxnum;
	spin_unlock(&blade->bs_lock);

	if (ngts) {
		gts->ustats.context_stolen++;
		ngts->ts_steal_jiffies = jiffies;
		gru_unload_context(ngts, is_kernel_context(ngts) ? 0 : 1);
		gts_stolen(ngts, blade);
	} else {
		STAT(steal_context_failed);
	}
	gru_dbg(grudev,
		"stole gid %d, ctxnum %d from gts %p. Need cb %d, ds %d;"
		" avail cb %ld, ds %ld\n",
		gru->gs_gid, ctxnum, ngts, cbr, dsr, hweight64(gru->gs_cbr_map),
		hweight64(gru->gs_dsr_map));
}

/*
 * Scan the GRUs on the local blade & assign a GRU context.
 */
struct gru_state *gru_assign_gru_context(struct gru_thread_state *gts,
						int blade)
{
	struct gru_state *gru, *grux;
	int i, max_active_contexts;


again:
	gru = NULL;
	max_active_contexts = GRU_NUM_CCH;
	for_each_gru_on_blade(grux, blade, i) {
		if (check_gru_resources(grux, gts->ts_cbr_au_count,
					gts->ts_dsr_au_count,
					max_active_contexts)) {
			gru = grux;
			max_active_contexts = grux->gs_active_contexts;
			if (max_active_contexts == 0)
				break;
		}
	}

	if (gru) {
		spin_lock(&gru->gs_lock);
		if (!check_gru_resources(gru, gts->ts_cbr_au_count,
					 gts->ts_dsr_au_count, GRU_NUM_CCH)) {
			spin_unlock(&gru->gs_lock);
			goto again;
		}
		reserve_gru_resources(gru, gts);
		gts->ts_gru = gru;
		gts->ts_blade = gru->gs_blade_id;
		gts->ts_ctxnum =
		    find_first_zero_bit(&gru->gs_context_map, GRU_NUM_CCH);
		BUG_ON(gts->ts_ctxnum == GRU_NUM_CCH);
		atomic_inc(&gts->ts_refcnt);
		gru->gs_gts[gts->ts_ctxnum] = gts;
		__set_bit(gts->ts_ctxnum, &gru->gs_context_map);
		spin_unlock(&gru->gs_lock);

		STAT(assign_context);
		gru_dbg(grudev,
			"gseg %p, gts %p, gid %d, ctx %d, cbr %d, dsr %d\n",
			gseg_virtual_address(gts->ts_gru, gts->ts_ctxnum), gts,
			gts->ts_gru->gs_gid, gts->ts_ctxnum,
			gts->ts_cbr_au_count, gts->ts_dsr_au_count);
	} else {
		gru_dbg(grudev, "failed to allocate a GTS %s\n", "");
		STAT(assign_context_failed);
	}

	return gru;
}

/*
 * gru_nopage
 *
 * Map the user's GRU segment
 *
 * 	Note: gru segments alway mmaped on GRU_GSEG_PAGESIZE boundaries.
 */
int gru_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct gru_thread_state *gts;
	unsigned long paddr, vaddr;
	int blade_id;

	vaddr = (unsigned long)vmf->virtual_address;
	gru_dbg(grudev, "vma %p, vaddr 0x%lx (0x%lx)\n",
		vma, vaddr, GSEG_BASE(vaddr));
	STAT(nopfn);

	/* The following check ensures vaddr is a valid address in the VMA */
	gts = gru_find_thread_state(vma, TSID(vaddr, vma));
	if (!gts)
		return VM_FAULT_SIGBUS;

again:
	mutex_lock(&gts->ts_ctxlock);
	preempt_disable();
	blade_id = uv_numa_blade_id();

	if (gts->ts_gru) {
		if (gts->ts_gru->gs_blade_id != blade_id) {
			STAT(migrated_nopfn_unload);
			gru_unload_context(gts, 1);
		} else {
			if (gru_retarget_intr(gts))
				STAT(migrated_nopfn_retarget);
		}
	}

	if (!gts->ts_gru) {
		STAT(load_user_context);
		if (!gru_assign_gru_context(gts, blade_id)) {
			preempt_enable();
			mutex_unlock(&gts->ts_ctxlock);
			set_current_state(TASK_INTERRUPTIBLE);
			schedule_timeout(GRU_ASSIGN_DELAY);  /* true hack ZZZ */
			blade_id = uv_numa_blade_id();
			if (gts->ts_steal_jiffies + GRU_STEAL_DELAY < jiffies)
				gru_steal_context(gts, blade_id);
			goto again;
		}
		gru_load_context(gts);
		paddr = gseg_physical_address(gts->ts_gru, gts->ts_ctxnum);
		remap_pfn_range(vma, vaddr & ~(GRU_GSEG_PAGESIZE - 1),
				paddr >> PAGE_SHIFT, GRU_GSEG_PAGESIZE,
				vma->vm_page_prot);
	}

	preempt_enable();
	mutex_unlock(&gts->ts_ctxlock);

	return VM_FAULT_NOPAGE;
}

OpenPOWER on IntegriCloud