aboutsummaryrefslogtreecommitdiffstats
path: root/arch/ppc/lib/rheap.c
blob: d40700795a9c05bc823a99378a3f6dd0885c9a39 (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
/*
 * A Remote Heap.  Remote means that we don't touch the memory that the
 * heap points to. Normal heap implementations use the memory they manage
 * to place their list. We cannot do that because the memory we manage may
 * have special properties, for example it is uncachable or of different
 * endianess.
 *
 * Author: Pantelis Antoniou <panto@intracom.gr>
 *
 * 2004 (c) INTRACOM S.A. Greece. This file is licensed under
 * the terms of the GNU General Public License version 2. This program
 * is licensed "as is" without any warranty of any kind, whether express
 * or implied.
 */
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>

#include <asm/rheap.h>

/*
 * Fixup a list_head, needed when copying lists.  If the pointers fall
 * between s and e, apply the delta.  This assumes that
 * sizeof(struct list_head *) == sizeof(unsigned long *).
 */
static inline void fixup(unsigned long s, unsigned long e, int d,
			 struct list_head *l)
{
	unsigned long *pp;

	pp = (unsigned long *)&l->next;
	if (*pp >= s && *pp < e)
		*pp += d;

	pp = (unsigned long *)&l->prev;
	if (*pp >= s && *pp < e)
		*pp += d;
}

/* Grow the allocated blocks */
static int grow(rh_info_t * info, int max_blocks)
{
	rh_block_t *block, *blk;
	int i, new_blocks;
	int delta;
	unsigned long blks, blke;

	if (max_blocks <= info->max_blocks)
		return -EINVAL;

	new_blocks = max_blocks - info->max_blocks;

	block = kmalloc(sizeof(rh_block_t) * max_blocks, GFP_KERNEL);
	if (block == NULL)
		return -ENOMEM;

	if (info->max_blocks > 0) {

		/* copy old block area */
		memcpy(block, info->block,
		       sizeof(rh_block_t) * info->max_blocks);

		delta = (char *)block - (char *)info->block;

		/* and fixup list pointers */
		blks = (unsigned long)info->block;
		blke = (unsigned long)(info->block + info->max_blocks);

		for (i = 0, blk = block; i < info->max_blocks; i++, blk++)
			fixup(blks, blke, delta, &blk->list);

		fixup(blks, blke, delta, &info->empty_list);
		fixup(blks, blke, delta, &info->free_list);
		fixup(blks, blke, delta, &info->taken_list);

		/* free the old allocated memory */
		if ((info->flags & RHIF_STATIC_BLOCK) == 0)
			kfree(info->block);
	}

	info->block = block;
	info->empty_slots += new_blocks;
	info->max_blocks = max_blocks;
	info->flags &= ~RHIF_STATIC_BLOCK;

	/* add all new blocks to the free list */
	for (i = 0, blk = block + info->max_blocks; i < new_blocks; i++, blk++)
		list_add(&blk->list, &info->empty_list);

	return 0;
}

/*
 * Assure at least the required amount of empty slots.  If this function
 * causes a grow in the block area then all pointers kept to the block
 * area are invalid!
 */
static int assure_empty(rh_info_t * info, int slots)
{
	int max_blocks;

	/* This function is not meant to be used to grow uncontrollably */
	if (slots >= 4)
		return -EINVAL;

	/* Enough space */
	if (info->empty_slots >= slots)
		return 0;

	/* Next 16 sized block */
	max_blocks = ((info->max_blocks + slots) + 15) & ~15;

	return grow(info, max_blocks);
}

static rh_block_t *get_slot(rh_info_t * info)
{
	rh_block_t *blk;

	/* If no more free slots, and failure to extend. */
	/* XXX: You should have called assure_empty before */
	if (info->empty_slots == 0) {
		printk(KERN_ERR "rh: out of slots; crash is imminent.\n");
		return NULL;
	}

	/* Get empty slot to use */
	blk = list_entry(info->empty_list.next, rh_block_t, list);
	list_del_init(&blk->list);
	info->empty_slots--;

	/* Initialize */
	blk->start = NULL;
	blk->size = 0;
	blk->owner = NULL;

	return blk;
}

static inline void release_slot(rh_info_t * info, rh_block_t * blk)
{
	list_add(&blk->list, &info->empty_list);
	info->empty_slots++;
}

static void attach_free_block(rh_info_t * info, rh_block_t * blkn)
{
	rh_block_t *blk;
	rh_block_t *before;
	rh_block_t *after;
	rh_block_t *next;
	int size;
	unsigned long s, e, bs, be;
	struct list_head *l;

	/* We assume that they are aligned properly */
	size = blkn->size;
	s = (unsigned long)blkn->start;
	e = s + size;

	/* Find the blocks immediately before and after the given one
	 * (if any) */
	before = NULL;
	after = NULL;
	next = NULL;

	list_for_each(l, &info->free_list) {
		blk = list_entry(l, rh_block_t, list);

		bs = (unsigned long)blk->start;
		be = bs + blk->size;

		if (next == NULL && s >= bs)
			next = blk;

		if (be == s)
			before = blk;

		if (e == bs)
			after = blk;

		/* If both are not null, break now */
		if (before != NULL && after != NULL)
			break;
	}

	/* Now check if they are really adjacent */
	if (before != NULL && s != (unsigned long)before->start + before->size)
		before = NULL;

	if (after != NULL && e != (unsigned long)after->start)
		after = NULL;

	/* No coalescing; list insert and return */
	if (before == NULL && after == NULL) {

		if (next != NULL)
			list_add(&blkn->list, &next->list);
		else
			list_add(&blkn->list, &info->free_list);

		return;
	}

	/* We don't need it anymore */
	release_slot(info, blkn);

	/* Grow the before block */
	if (before != NULL && after == NULL) {
		before->size += size;
		return;
	}

	/* Grow the after block backwards */
	if (before == NULL && after != NULL) {
		after->start = (int8_t *)after->start - size;
		after->size += size;
		return;
	}

	/* Grow the before block, and release the after block */
	before->size += size + after->size;
	list_del(&after->list);
	release_slot(info, after);
}

static void attach_taken_block(rh_info_t * info, rh_block_t * blkn)
{
	rh_block_t *blk;
	struct list_head *l;

	/* Find the block immediately before the given one (if any) */
	list_for_each(l, &info->taken_list) {
		blk = list_entry(l, rh_block_t, list);
		if (blk->start > blkn->start) {
			list_add_tail(&blkn->list, &blk->list);
			return;
		}
	}

	list_add_tail(&blkn->list, &info->taken_list);
}

/*
 * Create a remote heap dynamically.  Note that no memory for the blocks
 * are allocated.  It will upon the first allocation
 */
rh_info_t *rh_create(unsigned int alignment)
{
	rh_info_t *info;

	/* Alignment must be a power of two */
	if ((alignment & (alignment - 1)) != 0)
		return ERR_PTR(-EINVAL);

	info = kmalloc(sizeof(*info), GFP_KERNEL);
	if (info == NULL)
		return ERR_PTR(-ENOMEM);

	info->alignment = alignment;

	/* Initially everything as empty */
	info->block = NULL;
	info->max_blocks = 0;
	info->empty_slots = 0;
	info->flags = 0;

	INIT_LIST_HEAD(&info->empty_list);
	INIT_LIST_HEAD(&info->free_list);
	INIT_LIST_HEAD(&info->taken_list);

	return info;
}

/*
 * Destroy a dynamically created remote heap.  Deallocate only if the areas
 * are not static
 */
void rh_destroy(rh_info_t * info)
{
	if ((info->flags & RHIF_STATIC_BLOCK) == 0 && info->block != NULL)
		kfree(info->block);

	if ((info->flags & RHIF_STATIC_INFO) == 0)
		kfree(info);
}

/*
 * Initialize in place a remote heap info block.  This is needed to support
 * operation very early in the startup of the kernel, when it is not yet safe
 * to call kmalloc.
 */
void rh_init(rh_info_t * info, unsigned int alignment, int max_blocks,
	     rh_block_t * block)
{
	int i;
	rh_block_t *blk;

	/* Alignment must be a power of two */
	if ((alignment & (alignment - 1)) != 0)
		return;

	info->alignment = alignment;

	/* Initially everything as empty */
	info->block = block;
	info->max_blocks = max_blocks;
	info->empty_slots = max_blocks;
	info->flags = RHIF_STATIC_INFO | RHIF_STATIC_BLOCK;

	INIT_LIST_HEAD(&info->empty_list);
	INIT_LIST_HEAD(&info->free_list);
	INIT_LIST_HEAD(&info->taken_list);

	/* Add all new blocks to the free list */
	for (i = 0, blk = block; i < max_blocks; i++, blk++)
		list_add(&blk->list, &info->empty_list);
}

/* Attach a free memory region, coalesces regions if adjuscent */
int rh_attach_region(rh_info_t * info, void *start, int size)
{
	rh_block_t *blk;
	unsigned long s, e, m;
	int r;

	/* The region must be aligned */
	s = (unsigned long)start;
	e = s + size;
	m = info->alignment - 1;

	/* Round start up */
	s = (s + m) & ~m;

	/* Round end down */
	e = e & ~m;

	/* Take final values */
	start = (void *)s;
	size = (int)(e - s);

	/* Grow the blocks, if needed */
	r = assure_empty(info, 1);
	if (r < 0)
		return r;

	blk = get_slot(info);
	blk->start = start;
	blk->size = size;
	blk->owner = NULL;

	attach_free_block(info, blk);

	return 0;
}

/* Detatch given address range, splits free block if needed. */
void *rh_detach_region(rh_info_t * info, void *start, int size)
{
	struct list_head *l;
	rh_block_t *blk, *newblk;
	unsigned long s, e, m, bs, be;

	/* Validate size */
	if (size <= 0)
		return ERR_PTR(-EINVAL);

	/* The region must be aligned */
	s = (unsigned long)start;
	e = s + size;
	m = info->alignment - 1;

	/* Round start up */
	s = (s + m) & ~m;

	/* Round end down */
	e = e & ~m;

	if (assure_empty(info, 1) < 0)
		return ERR_PTR(-ENOMEM);

	blk = NULL;
	list_for_each(l, &info->free_list) {
		blk = list_entry(l, rh_block_t, list);
		/* The range must lie entirely inside one free block */
		bs = (unsigned long)blk->start;
		be = (unsigned long)blk->start + blk->size;
		if (s >= bs && e <= be)
			break;
		blk = NULL;
	}

	if (blk == NULL)
		return ERR_PTR(-ENOMEM);

	/* Perfect fit */
	if (bs == s && be == e) {
		/* Delete from free list, release slot */
		list_del(&blk->list);
		release_slot(info, blk);
		return (void *)s;
	}

	/* blk still in free list, with updated start and/or size */
	if (bs == s || be == e) {
		if (bs == s)
			blk->start = (int8_t *)blk->start + size;
		blk->size -= size;

	} else {
		/* The front free fragment */
		blk->size = s - bs;

		/* the back free fragment */
		newblk = get_slot(info);
		newblk->start = (void *)e;
		newblk->size = be - e;

		list_add(&newblk->list, &blk->list);
	}

	return (void *)s;
}

void *rh_alloc(rh_info_t * info, int size, const char *owner)
{
	struct list_head *l;
	rh_block_t *blk;
	rh_block_t *newblk;
	void *start;

	/* Validate size */
	if (size <= 0)
		return ERR_PTR(-EINVAL);

	/* Align to configured alignment */
	size = (size + (info->alignment - 1)) & ~(info->alignment - 1);

	if (assure_empty(info, 1) < 0)
		return ERR_PTR(-ENOMEM);

	blk = NULL;
	list_for_each(l, &info->free_list) {
		blk = list_entry(l, rh_block_t, list);
		if (size <= blk->size)
			break;
		blk = NULL;
	}

	if (blk == NULL)
		return ERR_PTR(-ENOMEM);

	/* Just fits */
	if (blk->size == size) {
		/* Move from free list to taken list */
		list_del(&blk->list);
		blk->owner = owner;
		start = blk->start;

		attach_taken_block(info, blk);

		return start;
	}

	newblk = get_slot(info);
	newblk->start = blk->start;
	newblk->size = size;
	newblk->owner = owner;

	/* blk still in free list, with updated start, size */
	blk->start = (int8_t *)blk->start + size;
	blk->size -= size;

	start = newblk->start;

	attach_taken_block(info, newblk);

	return start;
}

/* allocate at precisely the given address */
void *rh_alloc_fixed(rh_info_t * info, void *start, int size, const char *owner)
{
	struct list_head *l;
	rh_block_t *blk, *newblk1, *newblk2;
	unsigned long s, e, m, bs, be;

	/* Validate size */
	if (size <= 0)
		return ERR_PTR(-EINVAL);

	/* The region must be aligned */
	s = (unsigned long)start;
	e = s + size;
	m = info->alignment - 1;

	/* Round start up */
	s = (s + m) & ~m;

	/* Round end down */
	e = e & ~m;

	if (assure_empty(info, 2) < 0)
		return ERR_PTR(-ENOMEM);

	blk = NULL;
	list_for_each(l, &info->free_list) {
		blk = list_entry(l, rh_block_t, list);
		/* The range must lie entirely inside one free block */
		bs = (unsigned long)blk->start;
		be = (unsigned long)blk->start + blk->size;
		if (s >= bs && e <= be)
			break;
	}

	if (blk == NULL)
		return ERR_PTR(-ENOMEM);

	/* Perfect fit */
	if (bs == s && be == e) {
		/* Move from free list to taken list */
		list_del(&blk->list);
		blk->owner = owner;

		start = blk->start;
		attach_taken_block(info, blk);

		return start;

	}

	/* blk still in free list, with updated start and/or size */
	if (bs == s || be == e) {
		if (bs == s)
			blk->start = (int8_t *)blk->start + size;
		blk->size -= size;

	} else {
		/* The front free fragment */
		blk->size = s - bs;

		/* The back free fragment */
		newblk2 = get_slot(info);
		newblk2->start = (void *)e;
		newblk2->size = be - e;

		list_add(&newblk2->list, &blk->list);
	}

	newblk1 = get_slot(info);
	newblk1->start = (void *)s;
	newblk1->size = e - s;
	newblk1->owner = owner;

	start = newblk1->start;
	attach_taken_block(info, newblk1);

	return start;
}

int rh_free(rh_info_t * info, void *start)
{
	rh_block_t *blk, *blk2;
	struct list_head *l;
	int size;

	/* Linear search for block */
	blk = NULL;
	list_for_each(l, &info->taken_list) {
		blk2 = list_entry(l, rh_block_t, list);
		if (start < blk2->start)
			break;
		blk = blk2;
	}

	if (blk == NULL || start > (blk->start + blk->size))
		return -EINVAL;

	/* Remove from taken list */
	list_del(&blk->list);

	/* Get size of freed block */
	size = blk->size;
	attach_free_block(info, blk);

	return size;
}

int rh_get_stats(rh_info_t * info, int what, int max_stats, rh_stats_t * stats)
{
	rh_block_t *blk;
	struct list_head *l;
	struct list_head *h;
	int nr;

	switch (what) {

	case RHGS_FREE:
		h = &info->free_list;
		break;

	case RHGS_TAKEN:
		h = &info->taken_list;
		break;

	default:
		return -EINVAL;
	}

	/* Linear search for block */
	nr = 0;
	list_for_each(l, h) {
		blk = list_entry(l, rh_block_t, list);
		if (stats != NULL && nr < max_stats) {
			stats->start = blk->start;
			stats->size = blk->size;
			stats->owner = blk->owner;
			stats++;
		}
		nr++;
	}

	return nr;
}

int rh_set_owner(rh_info_t * info, void *start, const char *owner)
{
	rh_block_t *blk, *blk2;
	struct list_head *l;
	int size;

	/* Linear search for block */
	blk = NULL;
	list_for_each(l, &info->taken_list) {
		blk2 = list_entry(l, rh_block_t, list);
		if (start < blk2->start)
			break;
		blk = blk2;
	}

	if (blk == NULL || start > (blk->start + blk->size))
		return -EINVAL;

	blk->owner = owner;
	size = blk->size;

	return size;
}

void rh_dump(rh_info_t * info)
{
	static rh_stats_t st[32];	/* XXX maximum 32 blocks */
	int maxnr;
	int i, nr;

	maxnr = ARRAY_SIZE(st);

	printk(KERN_INFO
	       "info @0x%p (%d slots empty / %d max)\n",
	       info, info->empty_slots, info->max_blocks);

	printk(KERN_INFO "  Free:\n");
	nr = rh_get_stats(info, RHGS_FREE, maxnr, st);
	if (nr > maxnr)
		nr = maxnr;
	for (i = 0; i < nr; i++)
		printk(KERN_INFO
		       "    0x%p-0x%p (%u)\n",
		       st[i].start, (int8_t *) st[i].start + st[i].size,
		       st[i].size);
	printk(KERN_INFO "\n");

	printk(KERN_INFO "  Taken:\n");
	nr = rh_get_stats(info, RHGS_TAKEN, maxnr, st);
	if (nr > maxnr)
		nr = maxnr;
	for (i = 0; i < nr; i++)
		printk(KERN_INFO
		       "    0x%p-0x%p (%u) %s\n",
		       st[i].start, (int8_t *) st[i].start + st[i].size,
		       st[i].size, st[i].owner != NULL ? st[i].owner : "");
	printk(KERN_INFO "\n");
}

void rh_dump_blk(rh_info_t * info, rh_block_t * blk)
{
	printk(KERN_INFO
	       "blk @0x%p: 0x%p-0x%p (%u)\n",
	       blk, blk->start, (int8_t *) blk->start + blk->size, blk->size);
}