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1/**************************************************************************
2 *
3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
4 * Copyright 2016 Intel Corporation
5 * All Rights Reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the
9 * "Software"), to deal in the Software without restriction, including
10 * without limitation the rights to use, copy, modify, merge, publish,
11 * distribute, sub license, and/or sell copies of the Software, and to
12 * permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
14 *
15 * The above copyright notice and this permission notice (including the
16 * next paragraph) shall be included in all copies or substantial portions
17 * of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
22 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
23 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
25 * USE OR OTHER DEALINGS IN THE SOFTWARE.
26 *
27 *
28 **************************************************************************/
29
30/*
31 * Generic simple memory manager implementation. Intended to be used as a base
32 * class implementation for more advanced memory managers.
33 *
34 * Note that the algorithm used is quite simple and there might be substantial
35 * performance gains if a smarter free list is implemented. Currently it is
36 * just an unordered stack of free regions. This could easily be improved if
37 * an RB-tree is used instead. At least if we expect heavy fragmentation.
38 *
39 * Aligned allocations can also see improvement.
40 *
41 * Authors:
42 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
43 */
44
45#include <linux/export.h>
46#include <linux/interval_tree_generic.h>
47#include <linux/seq_file.h>
48#include <linux/slab.h>
49#include <linux/stacktrace.h>
50
51#include <drm/drm_mm.h>
52
53/**
54 * DOC: Overview
55 *
56 * drm_mm provides a simple range allocator. The drivers are free to use the
57 * resource allocator from the linux core if it suits them, the upside of drm_mm
58 * is that it's in the DRM core. Which means that it's easier to extend for
59 * some of the crazier special purpose needs of gpus.
60 *
61 * The main data struct is &drm_mm, allocations are tracked in &drm_mm_node.
62 * Drivers are free to embed either of them into their own suitable
63 * datastructures. drm_mm itself will not do any memory allocations of its own,
64 * so if drivers choose not to embed nodes they need to still allocate them
65 * themselves.
66 *
67 * The range allocator also supports reservation of preallocated blocks. This is
68 * useful for taking over initial mode setting configurations from the firmware,
69 * where an object needs to be created which exactly matches the firmware's
70 * scanout target. As long as the range is still free it can be inserted anytime
71 * after the allocator is initialized, which helps with avoiding looped
72 * dependencies in the driver load sequence.
73 *
74 * drm_mm maintains a stack of most recently freed holes, which of all
75 * simplistic datastructures seems to be a fairly decent approach to clustering
76 * allocations and avoiding too much fragmentation. This means free space
77 * searches are O(num_holes). Given that all the fancy features drm_mm supports
78 * something better would be fairly complex and since gfx thrashing is a fairly
79 * steep cliff not a real concern. Removing a node again is O(1).
80 *
81 * drm_mm supports a few features: Alignment and range restrictions can be
82 * supplied. Furthermore every &drm_mm_node has a color value (which is just an
83 * opaque unsigned long) which in conjunction with a driver callback can be used
84 * to implement sophisticated placement restrictions. The i915 DRM driver uses
85 * this to implement guard pages between incompatible caching domains in the
86 * graphics TT.
87 *
88 * Two behaviors are supported for searching and allocating: bottom-up and
89 * top-down. The default is bottom-up. Top-down allocation can be used if the
90 * memory area has different restrictions, or just to reduce fragmentation.
91 *
92 * Finally iteration helpers to walk all nodes and all holes are provided as are
93 * some basic allocator dumpers for debugging.
94 *
95 * Note that this range allocator is not thread-safe, drivers need to protect
96 * modifications with their own locking. The idea behind this is that for a full
97 * memory manager additional data needs to be protected anyway, hence internal
98 * locking would be fully redundant.
99 */
100
101#ifdef CONFIG_DRM_DEBUG_MM
102#include <linux/stackdepot.h>
103
104#define STACKDEPTH 32
105#define BUFSZ 4096
106
107static noinline void save_stack(struct drm_mm_node *node)
108{
109 unsigned long entries[STACKDEPTH];
110 unsigned int n;
111
112 n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
113
114 /* May be called under spinlock, so avoid sleeping */
115 node->stack = stack_depot_save(entries, n, GFP_NOWAIT);
116}
117
118static void show_leaks(struct drm_mm *mm)
119{
120 struct drm_mm_node *node;
121 unsigned long *entries;
122 unsigned int nr_entries;
123 char *buf;
124
125 buf = kmalloc(BUFSZ, GFP_KERNEL);
126 if (!buf)
127 return;
128
129 list_for_each_entry(node, drm_mm_nodes(mm), node_list) {
130 if (!node->stack) {
131 DRM_ERROR("node [%08llx + %08llx]: unknown owner\n",
132 node->start, node->size);
133 continue;
134 }
135
136 nr_entries = stack_depot_fetch(node->stack, &entries);
137 stack_trace_snprint(buf, BUFSZ, entries, nr_entries, 0);
138 DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s",
139 node->start, node->size, buf);
140 }
141
142 kfree(buf);
143}
144
145#undef STACKDEPTH
146#undef BUFSZ
147#else
148static void save_stack(struct drm_mm_node *node) { }
149static void show_leaks(struct drm_mm *mm) { }
150#endif
151
152#define START(node) ((node)->start)
153#define LAST(node) ((node)->start + (node)->size - 1)
154
155INTERVAL_TREE_DEFINE(struct drm_mm_node, rb,
156 u64, __subtree_last,
157 START, LAST, static inline, drm_mm_interval_tree)
158
159struct drm_mm_node *
160__drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last)
161{
162 return drm_mm_interval_tree_iter_first((struct rb_root_cached *)&mm->interval_tree,
163 start, last) ?: (struct drm_mm_node *)&mm->head_node;
164}
165EXPORT_SYMBOL(__drm_mm_interval_first);
166
167static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node,
168 struct drm_mm_node *node)
169{
170 struct drm_mm *mm = hole_node->mm;
171 struct rb_node **link, *rb;
172 struct drm_mm_node *parent;
173 bool leftmost;
174
175 node->__subtree_last = LAST(node);
176
177 if (drm_mm_node_allocated(hole_node)) {
178 rb = &hole_node->rb;
179 while (rb) {
180 parent = rb_entry(rb, struct drm_mm_node, rb);
181 if (parent->__subtree_last >= node->__subtree_last)
182 break;
183
184 parent->__subtree_last = node->__subtree_last;
185 rb = rb_parent(rb);
186 }
187
188 rb = &hole_node->rb;
189 link = &hole_node->rb.rb_right;
190 leftmost = false;
191 } else {
192 rb = NULL;
193 link = &mm->interval_tree.rb_root.rb_node;
194 leftmost = true;
195 }
196
197 while (*link) {
198 rb = *link;
199 parent = rb_entry(rb, struct drm_mm_node, rb);
200 if (parent->__subtree_last < node->__subtree_last)
201 parent->__subtree_last = node->__subtree_last;
202 if (node->start < parent->start) {
203 link = &parent->rb.rb_left;
204 } else {
205 link = &parent->rb.rb_right;
206 leftmost = false;
207 }
208 }
209
210 rb_link_node(&node->rb, rb, link);
211 rb_insert_augmented_cached(&node->rb, &mm->interval_tree, leftmost,
212 &drm_mm_interval_tree_augment);
213}
214
215#define HOLE_SIZE(NODE) ((NODE)->hole_size)
216#define HOLE_ADDR(NODE) (__drm_mm_hole_node_start(NODE))
217
218static u64 rb_to_hole_size(struct rb_node *rb)
219{
220 return rb_entry(rb, struct drm_mm_node, rb_hole_size)->hole_size;
221}
222
223static void insert_hole_size(struct rb_root_cached *root,
224 struct drm_mm_node *node)
225{
226 struct rb_node **link = &root->rb_root.rb_node, *rb = NULL;
227 u64 x = node->hole_size;
228 bool first = true;
229
230 while (*link) {
231 rb = *link;
232 if (x > rb_to_hole_size(rb)) {
233 link = &rb->rb_left;
234 } else {
235 link = &rb->rb_right;
236 first = false;
237 }
238 }
239
240 rb_link_node(&node->rb_hole_size, rb, link);
241 rb_insert_color_cached(&node->rb_hole_size, root, first);
242}
243
244RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,
245 struct drm_mm_node, rb_hole_addr,
246 u64, subtree_max_hole, HOLE_SIZE)
247
248static void insert_hole_addr(struct rb_root *root, struct drm_mm_node *node)
249{
250 struct rb_node **link = &root->rb_node, *rb_parent = NULL;
251 u64 start = HOLE_ADDR(node), subtree_max_hole = node->subtree_max_hole;
252 struct drm_mm_node *parent;
253
254 while (*link) {
255 rb_parent = *link;
256 parent = rb_entry(rb_parent, struct drm_mm_node, rb_hole_addr);
257 if (parent->subtree_max_hole < subtree_max_hole)
258 parent->subtree_max_hole = subtree_max_hole;
259 if (start < HOLE_ADDR(parent))
260 link = &parent->rb_hole_addr.rb_left;
261 else
262 link = &parent->rb_hole_addr.rb_right;
263 }
264
265 rb_link_node(&node->rb_hole_addr, rb_parent, link);
266 rb_insert_augmented(&node->rb_hole_addr, root, &augment_callbacks);
267}
268
269static void add_hole(struct drm_mm_node *node)
270{
271 struct drm_mm *mm = node->mm;
272
273 node->hole_size =
274 __drm_mm_hole_node_end(node) - __drm_mm_hole_node_start(node);
275 node->subtree_max_hole = node->hole_size;
276 DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
277
278 insert_hole_size(&mm->holes_size, node);
279 insert_hole_addr(&mm->holes_addr, node);
280
281 list_add(&node->hole_stack, &mm->hole_stack);
282}
283
284static void rm_hole(struct drm_mm_node *node)
285{
286 DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
287
288 list_del(&node->hole_stack);
289 rb_erase_cached(&node->rb_hole_size, &node->mm->holes_size);
290 rb_erase_augmented(&node->rb_hole_addr, &node->mm->holes_addr,
291 &augment_callbacks);
292 node->hole_size = 0;
293 node->subtree_max_hole = 0;
294
295 DRM_MM_BUG_ON(drm_mm_hole_follows(node));
296}
297
298static inline struct drm_mm_node *rb_hole_size_to_node(struct rb_node *rb)
299{
300 return rb_entry_safe(rb, struct drm_mm_node, rb_hole_size);
301}
302
303static inline struct drm_mm_node *rb_hole_addr_to_node(struct rb_node *rb)
304{
305 return rb_entry_safe(rb, struct drm_mm_node, rb_hole_addr);
306}
307
308static struct drm_mm_node *best_hole(struct drm_mm *mm, u64 size)
309{
310 struct rb_node *rb = mm->holes_size.rb_root.rb_node;
311 struct drm_mm_node *best = NULL;
312
313 do {
314 struct drm_mm_node *node =
315 rb_entry(rb, struct drm_mm_node, rb_hole_size);
316
317 if (size <= node->hole_size) {
318 best = node;
319 rb = rb->rb_right;
320 } else {
321 rb = rb->rb_left;
322 }
323 } while (rb);
324
325 return best;
326}
327
328static bool usable_hole_addr(struct rb_node *rb, u64 size)
329{
330 return rb && rb_hole_addr_to_node(rb)->subtree_max_hole >= size;
331}
332
333static struct drm_mm_node *find_hole_addr(struct drm_mm *mm, u64 addr, u64 size)
334{
335 struct rb_node *rb = mm->holes_addr.rb_node;
336 struct drm_mm_node *node = NULL;
337
338 while (rb) {
339 u64 hole_start;
340
341 if (!usable_hole_addr(rb, size))
342 break;
343
344 node = rb_hole_addr_to_node(rb);
345 hole_start = __drm_mm_hole_node_start(node);
346
347 if (addr < hole_start)
348 rb = node->rb_hole_addr.rb_left;
349 else if (addr > hole_start + node->hole_size)
350 rb = node->rb_hole_addr.rb_right;
351 else
352 break;
353 }
354
355 return node;
356}
357
358static struct drm_mm_node *
359first_hole(struct drm_mm *mm,
360 u64 start, u64 end, u64 size,
361 enum drm_mm_insert_mode mode)
362{
363 switch (mode) {
364 default:
365 case DRM_MM_INSERT_BEST:
366 return best_hole(mm, size);
367
368 case DRM_MM_INSERT_LOW:
369 return find_hole_addr(mm, start, size);
370
371 case DRM_MM_INSERT_HIGH:
372 return find_hole_addr(mm, end, size);
373
374 case DRM_MM_INSERT_EVICT:
375 return list_first_entry_or_null(&mm->hole_stack,
376 struct drm_mm_node,
377 hole_stack);
378 }
379}
380
381/**
382 * DECLARE_NEXT_HOLE_ADDR - macro to declare next hole functions
383 * @name: name of function to declare
384 * @first: first rb member to traverse (either rb_left or rb_right).
385 * @last: last rb member to traverse (either rb_right or rb_left).
386 *
387 * This macro declares a function to return the next hole of the addr rb tree.
388 * While traversing the tree we take the searched size into account and only
389 * visit branches with potential big enough holes.
390 */
391
392#define DECLARE_NEXT_HOLE_ADDR(name, first, last) \
393static struct drm_mm_node *name(struct drm_mm_node *entry, u64 size) \
394{ \
395 struct rb_node *parent, *node = &entry->rb_hole_addr; \
396 \
397 if (!entry || RB_EMPTY_NODE(node)) \
398 return NULL; \
399 \
400 if (usable_hole_addr(node->first, size)) { \
401 node = node->first; \
402 while (usable_hole_addr(node->last, size)) \
403 node = node->last; \
404 return rb_hole_addr_to_node(node); \
405 } \
406 \
407 while ((parent = rb_parent(node)) && node == parent->first) \
408 node = parent; \
409 \
410 return rb_hole_addr_to_node(parent); \
411}
412
413DECLARE_NEXT_HOLE_ADDR(next_hole_high_addr, rb_left, rb_right)
414DECLARE_NEXT_HOLE_ADDR(next_hole_low_addr, rb_right, rb_left)
415
416static struct drm_mm_node *
417next_hole(struct drm_mm *mm,
418 struct drm_mm_node *node,
419 u64 size,
420 enum drm_mm_insert_mode mode)
421{
422 switch (mode) {
423 default:
424 case DRM_MM_INSERT_BEST:
425 return rb_hole_size_to_node(rb_prev(&node->rb_hole_size));
426
427 case DRM_MM_INSERT_LOW:
428 return next_hole_low_addr(node, size);
429
430 case DRM_MM_INSERT_HIGH:
431 return next_hole_high_addr(node, size);
432
433 case DRM_MM_INSERT_EVICT:
434 node = list_next_entry(node, hole_stack);
435 return &node->hole_stack == &mm->hole_stack ? NULL : node;
436 }
437}
438
439/**
440 * drm_mm_reserve_node - insert an pre-initialized node
441 * @mm: drm_mm allocator to insert @node into
442 * @node: drm_mm_node to insert
443 *
444 * This functions inserts an already set-up &drm_mm_node into the allocator,
445 * meaning that start, size and color must be set by the caller. All other
446 * fields must be cleared to 0. This is useful to initialize the allocator with
447 * preallocated objects which must be set-up before the range allocator can be
448 * set-up, e.g. when taking over a firmware framebuffer.
449 *
450 * Returns:
451 * 0 on success, -ENOSPC if there's no hole where @node is.
452 */
453int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
454{
455 struct drm_mm_node *hole;
456 u64 hole_start, hole_end;
457 u64 adj_start, adj_end;
458 u64 end;
459
460 end = node->start + node->size;
461 if (unlikely(end <= node->start))
462 return -ENOSPC;
463
464 /* Find the relevant hole to add our node to */
465 hole = find_hole_addr(mm, node->start, 0);
466 if (!hole)
467 return -ENOSPC;
468
469 adj_start = hole_start = __drm_mm_hole_node_start(hole);
470 adj_end = hole_end = hole_start + hole->hole_size;
471
472 if (mm->color_adjust)
473 mm->color_adjust(hole, node->color, &adj_start, &adj_end);
474
475 if (adj_start > node->start || adj_end < end)
476 return -ENOSPC;
477
478 node->mm = mm;
479
480 __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
481 list_add(&node->node_list, &hole->node_list);
482 drm_mm_interval_tree_add_node(hole, node);
483 node->hole_size = 0;
484
485 rm_hole(hole);
486 if (node->start > hole_start)
487 add_hole(hole);
488 if (end < hole_end)
489 add_hole(node);
490
491 save_stack(node);
492 return 0;
493}
494EXPORT_SYMBOL(drm_mm_reserve_node);
495
496static u64 rb_to_hole_size_or_zero(struct rb_node *rb)
497{
498 return rb ? rb_to_hole_size(rb) : 0;
499}
500
501/**
502 * drm_mm_insert_node_in_range - ranged search for space and insert @node
503 * @mm: drm_mm to allocate from
504 * @node: preallocate node to insert
505 * @size: size of the allocation
506 * @alignment: alignment of the allocation
507 * @color: opaque tag value to use for this node
508 * @range_start: start of the allowed range for this node
509 * @range_end: end of the allowed range for this node
510 * @mode: fine-tune the allocation search and placement
511 *
512 * The preallocated @node must be cleared to 0.
513 *
514 * Returns:
515 * 0 on success, -ENOSPC if there's no suitable hole.
516 */
517int drm_mm_insert_node_in_range(struct drm_mm * const mm,
518 struct drm_mm_node * const node,
519 u64 size, u64 alignment,
520 unsigned long color,
521 u64 range_start, u64 range_end,
522 enum drm_mm_insert_mode mode)
523{
524 struct drm_mm_node *hole;
525 u64 remainder_mask;
526 bool once;
527
528 DRM_MM_BUG_ON(range_start > range_end);
529
530 if (unlikely(size == 0 || range_end - range_start < size))
531 return -ENOSPC;
532
533 if (rb_to_hole_size_or_zero(rb_first_cached(&mm->holes_size)) < size)
534 return -ENOSPC;
535
536 if (alignment <= 1)
537 alignment = 0;
538
539 once = mode & DRM_MM_INSERT_ONCE;
540 mode &= ~DRM_MM_INSERT_ONCE;
541
542 remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
543 for (hole = first_hole(mm, range_start, range_end, size, mode);
544 hole;
545 hole = once ? NULL : next_hole(mm, hole, size, mode)) {
546 u64 hole_start = __drm_mm_hole_node_start(hole);
547 u64 hole_end = hole_start + hole->hole_size;
548 u64 adj_start, adj_end;
549 u64 col_start, col_end;
550
551 if (mode == DRM_MM_INSERT_LOW && hole_start >= range_end)
552 break;
553
554 if (mode == DRM_MM_INSERT_HIGH && hole_end <= range_start)
555 break;
556
557 col_start = hole_start;
558 col_end = hole_end;
559 if (mm->color_adjust)
560 mm->color_adjust(hole, color, &col_start, &col_end);
561
562 adj_start = max(col_start, range_start);
563 adj_end = min(col_end, range_end);
564
565 if (adj_end <= adj_start || adj_end - adj_start < size)
566 continue;
567
568 if (mode == DRM_MM_INSERT_HIGH)
569 adj_start = adj_end - size;
570
571 if (alignment) {
572 u64 rem;
573
574 if (likely(remainder_mask))
575 rem = adj_start & remainder_mask;
576 else
577 div64_u64_rem(adj_start, alignment, &rem);
578 if (rem) {
579 adj_start -= rem;
580 if (mode != DRM_MM_INSERT_HIGH)
581 adj_start += alignment;
582
583 if (adj_start < max(col_start, range_start) ||
584 min(col_end, range_end) - adj_start < size)
585 continue;
586
587 if (adj_end <= adj_start ||
588 adj_end - adj_start < size)
589 continue;
590 }
591 }
592
593 node->mm = mm;
594 node->size = size;
595 node->start = adj_start;
596 node->color = color;
597 node->hole_size = 0;
598
599 __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
600 list_add(&node->node_list, &hole->node_list);
601 drm_mm_interval_tree_add_node(hole, node);
602
603 rm_hole(hole);
604 if (adj_start > hole_start)
605 add_hole(hole);
606 if (adj_start + size < hole_end)
607 add_hole(node);
608
609 save_stack(node);
610 return 0;
611 }
612
613 return -ENOSPC;
614}
615EXPORT_SYMBOL(drm_mm_insert_node_in_range);
616
617static inline bool drm_mm_node_scanned_block(const struct drm_mm_node *node)
618{
619 return test_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
620}
621
622/**
623 * drm_mm_remove_node - Remove a memory node from the allocator.
624 * @node: drm_mm_node to remove
625 *
626 * This just removes a node from its drm_mm allocator. The node does not need to
627 * be cleared again before it can be re-inserted into this or any other drm_mm
628 * allocator. It is a bug to call this function on a unallocated node.
629 */
630void drm_mm_remove_node(struct drm_mm_node *node)
631{
632 struct drm_mm *mm = node->mm;
633 struct drm_mm_node *prev_node;
634
635 DRM_MM_BUG_ON(!drm_mm_node_allocated(node));
636 DRM_MM_BUG_ON(drm_mm_node_scanned_block(node));
637
638 prev_node = list_prev_entry(node, node_list);
639
640 if (drm_mm_hole_follows(node))
641 rm_hole(node);
642
643 drm_mm_interval_tree_remove(node, &mm->interval_tree);
644 list_del(&node->node_list);
645
646 if (drm_mm_hole_follows(prev_node))
647 rm_hole(prev_node);
648 add_hole(prev_node);
649
650 clear_bit_unlock(DRM_MM_NODE_ALLOCATED_BIT, &node->flags);
651}
652EXPORT_SYMBOL(drm_mm_remove_node);
653
654/**
655 * drm_mm_replace_node - move an allocation from @old to @new
656 * @old: drm_mm_node to remove from the allocator
657 * @new: drm_mm_node which should inherit @old's allocation
658 *
659 * This is useful for when drivers embed the drm_mm_node structure and hence
660 * can't move allocations by reassigning pointers. It's a combination of remove
661 * and insert with the guarantee that the allocation start will match.
662 */
663void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
664{
665 struct drm_mm *mm = old->mm;
666
667 DRM_MM_BUG_ON(!drm_mm_node_allocated(old));
668
669 *new = *old;
670
671 __set_bit(DRM_MM_NODE_ALLOCATED_BIT, &new->flags);
672 list_replace(&old->node_list, &new->node_list);
673 rb_replace_node_cached(&old->rb, &new->rb, &mm->interval_tree);
674
675 if (drm_mm_hole_follows(old)) {
676 list_replace(&old->hole_stack, &new->hole_stack);
677 rb_replace_node_cached(&old->rb_hole_size,
678 &new->rb_hole_size,
679 &mm->holes_size);
680 rb_replace_node(&old->rb_hole_addr,
681 &new->rb_hole_addr,
682 &mm->holes_addr);
683 }
684
685 clear_bit_unlock(DRM_MM_NODE_ALLOCATED_BIT, &old->flags);
686}
687EXPORT_SYMBOL(drm_mm_replace_node);
688
689/**
690 * DOC: lru scan roster
691 *
692 * Very often GPUs need to have continuous allocations for a given object. When
693 * evicting objects to make space for a new one it is therefore not most
694 * efficient when we simply start to select all objects from the tail of an LRU
695 * until there's a suitable hole: Especially for big objects or nodes that
696 * otherwise have special allocation constraints there's a good chance we evict
697 * lots of (smaller) objects unnecessarily.
698 *
699 * The DRM range allocator supports this use-case through the scanning
700 * interfaces. First a scan operation needs to be initialized with
701 * drm_mm_scan_init() or drm_mm_scan_init_with_range(). The driver adds
702 * objects to the roster, probably by walking an LRU list, but this can be
703 * freely implemented. Eviction candiates are added using
704 * drm_mm_scan_add_block() until a suitable hole is found or there are no
705 * further evictable objects. Eviction roster metadata is tracked in &struct
706 * drm_mm_scan.
707 *
708 * The driver must walk through all objects again in exactly the reverse
709 * order to restore the allocator state. Note that while the allocator is used
710 * in the scan mode no other operation is allowed.
711 *
712 * Finally the driver evicts all objects selected (drm_mm_scan_remove_block()
713 * reported true) in the scan, and any overlapping nodes after color adjustment
714 * (drm_mm_scan_color_evict()). Adding and removing an object is O(1), and
715 * since freeing a node is also O(1) the overall complexity is
716 * O(scanned_objects). So like the free stack which needs to be walked before a
717 * scan operation even begins this is linear in the number of objects. It
718 * doesn't seem to hurt too badly.
719 */
720
721/**
722 * drm_mm_scan_init_with_range - initialize range-restricted lru scanning
723 * @scan: scan state
724 * @mm: drm_mm to scan
725 * @size: size of the allocation
726 * @alignment: alignment of the allocation
727 * @color: opaque tag value to use for the allocation
728 * @start: start of the allowed range for the allocation
729 * @end: end of the allowed range for the allocation
730 * @mode: fine-tune the allocation search and placement
731 *
732 * This simply sets up the scanning routines with the parameters for the desired
733 * hole.
734 *
735 * Warning:
736 * As long as the scan list is non-empty, no other operations than
737 * adding/removing nodes to/from the scan list are allowed.
738 */
739void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
740 struct drm_mm *mm,
741 u64 size,
742 u64 alignment,
743 unsigned long color,
744 u64 start,
745 u64 end,
746 enum drm_mm_insert_mode mode)
747{
748 DRM_MM_BUG_ON(start >= end);
749 DRM_MM_BUG_ON(!size || size > end - start);
750 DRM_MM_BUG_ON(mm->scan_active);
751
752 scan->mm = mm;
753
754 if (alignment <= 1)
755 alignment = 0;
756
757 scan->color = color;
758 scan->alignment = alignment;
759 scan->remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
760 scan->size = size;
761 scan->mode = mode;
762
763 DRM_MM_BUG_ON(end <= start);
764 scan->range_start = start;
765 scan->range_end = end;
766
767 scan->hit_start = U64_MAX;
768 scan->hit_end = 0;
769}
770EXPORT_SYMBOL(drm_mm_scan_init_with_range);
771
772/**
773 * drm_mm_scan_add_block - add a node to the scan list
774 * @scan: the active drm_mm scanner
775 * @node: drm_mm_node to add
776 *
777 * Add a node to the scan list that might be freed to make space for the desired
778 * hole.
779 *
780 * Returns:
781 * True if a hole has been found, false otherwise.
782 */
783bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
784 struct drm_mm_node *node)
785{
786 struct drm_mm *mm = scan->mm;
787 struct drm_mm_node *hole;
788 u64 hole_start, hole_end;
789 u64 col_start, col_end;
790 u64 adj_start, adj_end;
791
792 DRM_MM_BUG_ON(node->mm != mm);
793 DRM_MM_BUG_ON(!drm_mm_node_allocated(node));
794 DRM_MM_BUG_ON(drm_mm_node_scanned_block(node));
795 __set_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
796 mm->scan_active++;
797
798 /* Remove this block from the node_list so that we enlarge the hole
799 * (distance between the end of our previous node and the start of
800 * or next), without poisoning the link so that we can restore it
801 * later in drm_mm_scan_remove_block().
802 */
803 hole = list_prev_entry(node, node_list);
804 DRM_MM_BUG_ON(list_next_entry(hole, node_list) != node);
805 __list_del_entry(&node->node_list);
806
807 hole_start = __drm_mm_hole_node_start(hole);
808 hole_end = __drm_mm_hole_node_end(hole);
809
810 col_start = hole_start;
811 col_end = hole_end;
812 if (mm->color_adjust)
813 mm->color_adjust(hole, scan->color, &col_start, &col_end);
814
815 adj_start = max(col_start, scan->range_start);
816 adj_end = min(col_end, scan->range_end);
817 if (adj_end <= adj_start || adj_end - adj_start < scan->size)
818 return false;
819
820 if (scan->mode == DRM_MM_INSERT_HIGH)
821 adj_start = adj_end - scan->size;
822
823 if (scan->alignment) {
824 u64 rem;
825
826 if (likely(scan->remainder_mask))
827 rem = adj_start & scan->remainder_mask;
828 else
829 div64_u64_rem(adj_start, scan->alignment, &rem);
830 if (rem) {
831 adj_start -= rem;
832 if (scan->mode != DRM_MM_INSERT_HIGH)
833 adj_start += scan->alignment;
834 if (adj_start < max(col_start, scan->range_start) ||
835 min(col_end, scan->range_end) - adj_start < scan->size)
836 return false;
837
838 if (adj_end <= adj_start ||
839 adj_end - adj_start < scan->size)
840 return false;
841 }
842 }
843
844 scan->hit_start = adj_start;
845 scan->hit_end = adj_start + scan->size;
846
847 DRM_MM_BUG_ON(scan->hit_start >= scan->hit_end);
848 DRM_MM_BUG_ON(scan->hit_start < hole_start);
849 DRM_MM_BUG_ON(scan->hit_end > hole_end);
850
851 return true;
852}
853EXPORT_SYMBOL(drm_mm_scan_add_block);
854
855/**
856 * drm_mm_scan_remove_block - remove a node from the scan list
857 * @scan: the active drm_mm scanner
858 * @node: drm_mm_node to remove
859 *
860 * Nodes **must** be removed in exactly the reverse order from the scan list as
861 * they have been added (e.g. using list_add() as they are added and then
862 * list_for_each() over that eviction list to remove), otherwise the internal
863 * state of the memory manager will be corrupted.
864 *
865 * When the scan list is empty, the selected memory nodes can be freed. An
866 * immediately following drm_mm_insert_node_in_range_generic() or one of the
867 * simpler versions of that function with !DRM_MM_SEARCH_BEST will then return
868 * the just freed block (because it's at the top of the free_stack list).
869 *
870 * Returns:
871 * True if this block should be evicted, false otherwise. Will always
872 * return false when no hole has been found.
873 */
874bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,
875 struct drm_mm_node *node)
876{
877 struct drm_mm_node *prev_node;
878
879 DRM_MM_BUG_ON(node->mm != scan->mm);
880 DRM_MM_BUG_ON(!drm_mm_node_scanned_block(node));
881 __clear_bit(DRM_MM_NODE_SCANNED_BIT, &node->flags);
882
883 DRM_MM_BUG_ON(!node->mm->scan_active);
884 node->mm->scan_active--;
885
886 /* During drm_mm_scan_add_block() we decoupled this node leaving
887 * its pointers intact. Now that the caller is walking back along
888 * the eviction list we can restore this block into its rightful
889 * place on the full node_list. To confirm that the caller is walking
890 * backwards correctly we check that prev_node->next == node->next,
891 * i.e. both believe the same node should be on the other side of the
892 * hole.
893 */
894 prev_node = list_prev_entry(node, node_list);
895 DRM_MM_BUG_ON(list_next_entry(prev_node, node_list) !=
896 list_next_entry(node, node_list));
897 list_add(&node->node_list, &prev_node->node_list);
898
899 return (node->start + node->size > scan->hit_start &&
900 node->start < scan->hit_end);
901}
902EXPORT_SYMBOL(drm_mm_scan_remove_block);
903
904/**
905 * drm_mm_scan_color_evict - evict overlapping nodes on either side of hole
906 * @scan: drm_mm scan with target hole
907 *
908 * After completing an eviction scan and removing the selected nodes, we may
909 * need to remove a few more nodes from either side of the target hole if
910 * mm.color_adjust is being used.
911 *
912 * Returns:
913 * A node to evict, or NULL if there are no overlapping nodes.
914 */
915struct drm_mm_node *drm_mm_scan_color_evict(struct drm_mm_scan *scan)
916{
917 struct drm_mm *mm = scan->mm;
918 struct drm_mm_node *hole;
919 u64 hole_start, hole_end;
920
921 DRM_MM_BUG_ON(list_empty(&mm->hole_stack));
922
923 if (!mm->color_adjust)
924 return NULL;
925
926 /*
927 * The hole found during scanning should ideally be the first element
928 * in the hole_stack list, but due to side-effects in the driver it
929 * may not be.
930 */
931 list_for_each_entry(hole, &mm->hole_stack, hole_stack) {
932 hole_start = __drm_mm_hole_node_start(hole);
933 hole_end = hole_start + hole->hole_size;
934
935 if (hole_start <= scan->hit_start &&
936 hole_end >= scan->hit_end)
937 break;
938 }
939
940 /* We should only be called after we found the hole previously */
941 DRM_MM_BUG_ON(&hole->hole_stack == &mm->hole_stack);
942 if (unlikely(&hole->hole_stack == &mm->hole_stack))
943 return NULL;
944
945 DRM_MM_BUG_ON(hole_start > scan->hit_start);
946 DRM_MM_BUG_ON(hole_end < scan->hit_end);
947
948 mm->color_adjust(hole, scan->color, &hole_start, &hole_end);
949 if (hole_start > scan->hit_start)
950 return hole;
951 if (hole_end < scan->hit_end)
952 return list_next_entry(hole, node_list);
953
954 return NULL;
955}
956EXPORT_SYMBOL(drm_mm_scan_color_evict);
957
958/**
959 * drm_mm_init - initialize a drm-mm allocator
960 * @mm: the drm_mm structure to initialize
961 * @start: start of the range managed by @mm
962 * @size: end of the range managed by @mm
963 *
964 * Note that @mm must be cleared to 0 before calling this function.
965 */
966void drm_mm_init(struct drm_mm *mm, u64 start, u64 size)
967{
968 DRM_MM_BUG_ON(start + size <= start);
969
970 mm->color_adjust = NULL;
971
972 INIT_LIST_HEAD(&mm->hole_stack);
973 mm->interval_tree = RB_ROOT_CACHED;
974 mm->holes_size = RB_ROOT_CACHED;
975 mm->holes_addr = RB_ROOT;
976
977 /* Clever trick to avoid a special case in the free hole tracking. */
978 INIT_LIST_HEAD(&mm->head_node.node_list);
979 mm->head_node.flags = 0;
980 mm->head_node.mm = mm;
981 mm->head_node.start = start + size;
982 mm->head_node.size = -size;
983 add_hole(&mm->head_node);
984
985 mm->scan_active = 0;
986}
987EXPORT_SYMBOL(drm_mm_init);
988
989/**
990 * drm_mm_takedown - clean up a drm_mm allocator
991 * @mm: drm_mm allocator to clean up
992 *
993 * Note that it is a bug to call this function on an allocator which is not
994 * clean.
995 */
996void drm_mm_takedown(struct drm_mm *mm)
997{
998 if (WARN(!drm_mm_clean(mm),
999 "Memory manager not clean during takedown.\n"))
1000 show_leaks(mm);
1001}
1002EXPORT_SYMBOL(drm_mm_takedown);
1003
1004static u64 drm_mm_dump_hole(struct drm_printer *p, const struct drm_mm_node *entry)
1005{
1006 u64 start, size;
1007
1008 size = entry->hole_size;
1009 if (size) {
1010 start = drm_mm_hole_node_start(entry);
1011 drm_printf(p, "%#018llx-%#018llx: %llu: free\n",
1012 start, start + size, size);
1013 }
1014
1015 return size;
1016}
1017/**
1018 * drm_mm_print - print allocator state
1019 * @mm: drm_mm allocator to print
1020 * @p: DRM printer to use
1021 */
1022void drm_mm_print(const struct drm_mm *mm, struct drm_printer *p)
1023{
1024 const struct drm_mm_node *entry;
1025 u64 total_used = 0, total_free = 0, total = 0;
1026
1027 total_free += drm_mm_dump_hole(p, &mm->head_node);
1028
1029 drm_mm_for_each_node(entry, mm) {
1030 drm_printf(p, "%#018llx-%#018llx: %llu: used\n", entry->start,
1031 entry->start + entry->size, entry->size);
1032 total_used += entry->size;
1033 total_free += drm_mm_dump_hole(p, entry);
1034 }
1035 total = total_free + total_used;
1036
1037 drm_printf(p, "total: %llu, used %llu free %llu\n", total,
1038 total_used, total_free);
1039}
1040EXPORT_SYMBOL(drm_mm_print);
1/**************************************************************************
2 *
3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
4 * Copyright 2016 Intel Corporation
5 * All Rights Reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the
9 * "Software"), to deal in the Software without restriction, including
10 * without limitation the rights to use, copy, modify, merge, publish,
11 * distribute, sub license, and/or sell copies of the Software, and to
12 * permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
14 *
15 * The above copyright notice and this permission notice (including the
16 * next paragraph) shall be included in all copies or substantial portions
17 * of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
22 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
23 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
25 * USE OR OTHER DEALINGS IN THE SOFTWARE.
26 *
27 *
28 **************************************************************************/
29
30/*
31 * Generic simple memory manager implementation. Intended to be used as a base
32 * class implementation for more advanced memory managers.
33 *
34 * Note that the algorithm used is quite simple and there might be substantial
35 * performance gains if a smarter free list is implemented. Currently it is
36 * just an unordered stack of free regions. This could easily be improved if
37 * an RB-tree is used instead. At least if we expect heavy fragmentation.
38 *
39 * Aligned allocations can also see improvement.
40 *
41 * Authors:
42 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
43 */
44
45#include <drm/drmP.h>
46#include <drm/drm_mm.h>
47#include <linux/slab.h>
48#include <linux/seq_file.h>
49#include <linux/export.h>
50#include <linux/interval_tree_generic.h>
51
52/**
53 * DOC: Overview
54 *
55 * drm_mm provides a simple range allocator. The drivers are free to use the
56 * resource allocator from the linux core if it suits them, the upside of drm_mm
57 * is that it's in the DRM core. Which means that it's easier to extend for
58 * some of the crazier special purpose needs of gpus.
59 *
60 * The main data struct is &drm_mm, allocations are tracked in &drm_mm_node.
61 * Drivers are free to embed either of them into their own suitable
62 * datastructures. drm_mm itself will not do any memory allocations of its own,
63 * so if drivers choose not to embed nodes they need to still allocate them
64 * themselves.
65 *
66 * The range allocator also supports reservation of preallocated blocks. This is
67 * useful for taking over initial mode setting configurations from the firmware,
68 * where an object needs to be created which exactly matches the firmware's
69 * scanout target. As long as the range is still free it can be inserted anytime
70 * after the allocator is initialized, which helps with avoiding looped
71 * dependencies in the driver load sequence.
72 *
73 * drm_mm maintains a stack of most recently freed holes, which of all
74 * simplistic datastructures seems to be a fairly decent approach to clustering
75 * allocations and avoiding too much fragmentation. This means free space
76 * searches are O(num_holes). Given that all the fancy features drm_mm supports
77 * something better would be fairly complex and since gfx thrashing is a fairly
78 * steep cliff not a real concern. Removing a node again is O(1).
79 *
80 * drm_mm supports a few features: Alignment and range restrictions can be
81 * supplied. Furthermore every &drm_mm_node has a color value (which is just an
82 * opaque unsigned long) which in conjunction with a driver callback can be used
83 * to implement sophisticated placement restrictions. The i915 DRM driver uses
84 * this to implement guard pages between incompatible caching domains in the
85 * graphics TT.
86 *
87 * Two behaviors are supported for searching and allocating: bottom-up and
88 * top-down. The default is bottom-up. Top-down allocation can be used if the
89 * memory area has different restrictions, or just to reduce fragmentation.
90 *
91 * Finally iteration helpers to walk all nodes and all holes are provided as are
92 * some basic allocator dumpers for debugging.
93 *
94 * Note that this range allocator is not thread-safe, drivers need to protect
95 * modifications with their own locking. The idea behind this is that for a full
96 * memory manager additional data needs to be protected anyway, hence internal
97 * locking would be fully redundant.
98 */
99
100#ifdef CONFIG_DRM_DEBUG_MM
101#include <linux/stackdepot.h>
102
103#define STACKDEPTH 32
104#define BUFSZ 4096
105
106static noinline void save_stack(struct drm_mm_node *node)
107{
108 unsigned long entries[STACKDEPTH];
109 struct stack_trace trace = {
110 .entries = entries,
111 .max_entries = STACKDEPTH,
112 .skip = 1
113 };
114
115 save_stack_trace(&trace);
116 if (trace.nr_entries != 0 &&
117 trace.entries[trace.nr_entries-1] == ULONG_MAX)
118 trace.nr_entries--;
119
120 /* May be called under spinlock, so avoid sleeping */
121 node->stack = depot_save_stack(&trace, GFP_NOWAIT);
122}
123
124static void show_leaks(struct drm_mm *mm)
125{
126 struct drm_mm_node *node;
127 unsigned long entries[STACKDEPTH];
128 char *buf;
129
130 buf = kmalloc(BUFSZ, GFP_KERNEL);
131 if (!buf)
132 return;
133
134 list_for_each_entry(node, drm_mm_nodes(mm), node_list) {
135 struct stack_trace trace = {
136 .entries = entries,
137 .max_entries = STACKDEPTH
138 };
139
140 if (!node->stack) {
141 DRM_ERROR("node [%08llx + %08llx]: unknown owner\n",
142 node->start, node->size);
143 continue;
144 }
145
146 depot_fetch_stack(node->stack, &trace);
147 snprint_stack_trace(buf, BUFSZ, &trace, 0);
148 DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s",
149 node->start, node->size, buf);
150 }
151
152 kfree(buf);
153}
154
155#undef STACKDEPTH
156#undef BUFSZ
157#else
158static void save_stack(struct drm_mm_node *node) { }
159static void show_leaks(struct drm_mm *mm) { }
160#endif
161
162#define START(node) ((node)->start)
163#define LAST(node) ((node)->start + (node)->size - 1)
164
165INTERVAL_TREE_DEFINE(struct drm_mm_node, rb,
166 u64, __subtree_last,
167 START, LAST, static inline, drm_mm_interval_tree)
168
169struct drm_mm_node *
170__drm_mm_interval_first(const struct drm_mm *mm, u64 start, u64 last)
171{
172 return drm_mm_interval_tree_iter_first((struct rb_root_cached *)&mm->interval_tree,
173 start, last) ?: (struct drm_mm_node *)&mm->head_node;
174}
175EXPORT_SYMBOL(__drm_mm_interval_first);
176
177static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node,
178 struct drm_mm_node *node)
179{
180 struct drm_mm *mm = hole_node->mm;
181 struct rb_node **link, *rb;
182 struct drm_mm_node *parent;
183 bool leftmost;
184
185 node->__subtree_last = LAST(node);
186
187 if (hole_node->allocated) {
188 rb = &hole_node->rb;
189 while (rb) {
190 parent = rb_entry(rb, struct drm_mm_node, rb);
191 if (parent->__subtree_last >= node->__subtree_last)
192 break;
193
194 parent->__subtree_last = node->__subtree_last;
195 rb = rb_parent(rb);
196 }
197
198 rb = &hole_node->rb;
199 link = &hole_node->rb.rb_right;
200 leftmost = false;
201 } else {
202 rb = NULL;
203 link = &mm->interval_tree.rb_root.rb_node;
204 leftmost = true;
205 }
206
207 while (*link) {
208 rb = *link;
209 parent = rb_entry(rb, struct drm_mm_node, rb);
210 if (parent->__subtree_last < node->__subtree_last)
211 parent->__subtree_last = node->__subtree_last;
212 if (node->start < parent->start) {
213 link = &parent->rb.rb_left;
214 } else {
215 link = &parent->rb.rb_right;
216 leftmost = false;
217 }
218 }
219
220 rb_link_node(&node->rb, rb, link);
221 rb_insert_augmented_cached(&node->rb, &mm->interval_tree, leftmost,
222 &drm_mm_interval_tree_augment);
223}
224
225#define RB_INSERT(root, member, expr) do { \
226 struct rb_node **link = &root.rb_node, *rb = NULL; \
227 u64 x = expr(node); \
228 while (*link) { \
229 rb = *link; \
230 if (x < expr(rb_entry(rb, struct drm_mm_node, member))) \
231 link = &rb->rb_left; \
232 else \
233 link = &rb->rb_right; \
234 } \
235 rb_link_node(&node->member, rb, link); \
236 rb_insert_color(&node->member, &root); \
237} while (0)
238
239#define HOLE_SIZE(NODE) ((NODE)->hole_size)
240#define HOLE_ADDR(NODE) (__drm_mm_hole_node_start(NODE))
241
242static void add_hole(struct drm_mm_node *node)
243{
244 struct drm_mm *mm = node->mm;
245
246 node->hole_size =
247 __drm_mm_hole_node_end(node) - __drm_mm_hole_node_start(node);
248 DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
249
250 RB_INSERT(mm->holes_size, rb_hole_size, HOLE_SIZE);
251 RB_INSERT(mm->holes_addr, rb_hole_addr, HOLE_ADDR);
252
253 list_add(&node->hole_stack, &mm->hole_stack);
254}
255
256static void rm_hole(struct drm_mm_node *node)
257{
258 DRM_MM_BUG_ON(!drm_mm_hole_follows(node));
259
260 list_del(&node->hole_stack);
261 rb_erase(&node->rb_hole_size, &node->mm->holes_size);
262 rb_erase(&node->rb_hole_addr, &node->mm->holes_addr);
263 node->hole_size = 0;
264
265 DRM_MM_BUG_ON(drm_mm_hole_follows(node));
266}
267
268static inline struct drm_mm_node *rb_hole_size_to_node(struct rb_node *rb)
269{
270 return rb_entry_safe(rb, struct drm_mm_node, rb_hole_size);
271}
272
273static inline struct drm_mm_node *rb_hole_addr_to_node(struct rb_node *rb)
274{
275 return rb_entry_safe(rb, struct drm_mm_node, rb_hole_addr);
276}
277
278static inline u64 rb_hole_size(struct rb_node *rb)
279{
280 return rb_entry(rb, struct drm_mm_node, rb_hole_size)->hole_size;
281}
282
283static struct drm_mm_node *best_hole(struct drm_mm *mm, u64 size)
284{
285 struct rb_node *best = NULL;
286 struct rb_node **link = &mm->holes_size.rb_node;
287
288 while (*link) {
289 struct rb_node *rb = *link;
290
291 if (size <= rb_hole_size(rb)) {
292 link = &rb->rb_left;
293 best = rb;
294 } else {
295 link = &rb->rb_right;
296 }
297 }
298
299 return rb_hole_size_to_node(best);
300}
301
302static struct drm_mm_node *find_hole(struct drm_mm *mm, u64 addr)
303{
304 struct drm_mm_node *node = NULL;
305 struct rb_node **link = &mm->holes_addr.rb_node;
306
307 while (*link) {
308 u64 hole_start;
309
310 node = rb_hole_addr_to_node(*link);
311 hole_start = __drm_mm_hole_node_start(node);
312
313 if (addr < hole_start)
314 link = &node->rb_hole_addr.rb_left;
315 else if (addr > hole_start + node->hole_size)
316 link = &node->rb_hole_addr.rb_right;
317 else
318 break;
319 }
320
321 return node;
322}
323
324static struct drm_mm_node *
325first_hole(struct drm_mm *mm,
326 u64 start, u64 end, u64 size,
327 enum drm_mm_insert_mode mode)
328{
329 if (RB_EMPTY_ROOT(&mm->holes_size))
330 return NULL;
331
332 switch (mode) {
333 default:
334 case DRM_MM_INSERT_BEST:
335 return best_hole(mm, size);
336
337 case DRM_MM_INSERT_LOW:
338 return find_hole(mm, start);
339
340 case DRM_MM_INSERT_HIGH:
341 return find_hole(mm, end);
342
343 case DRM_MM_INSERT_EVICT:
344 return list_first_entry_or_null(&mm->hole_stack,
345 struct drm_mm_node,
346 hole_stack);
347 }
348}
349
350static struct drm_mm_node *
351next_hole(struct drm_mm *mm,
352 struct drm_mm_node *node,
353 enum drm_mm_insert_mode mode)
354{
355 switch (mode) {
356 default:
357 case DRM_MM_INSERT_BEST:
358 return rb_hole_size_to_node(rb_next(&node->rb_hole_size));
359
360 case DRM_MM_INSERT_LOW:
361 return rb_hole_addr_to_node(rb_next(&node->rb_hole_addr));
362
363 case DRM_MM_INSERT_HIGH:
364 return rb_hole_addr_to_node(rb_prev(&node->rb_hole_addr));
365
366 case DRM_MM_INSERT_EVICT:
367 node = list_next_entry(node, hole_stack);
368 return &node->hole_stack == &mm->hole_stack ? NULL : node;
369 }
370}
371
372/**
373 * drm_mm_reserve_node - insert an pre-initialized node
374 * @mm: drm_mm allocator to insert @node into
375 * @node: drm_mm_node to insert
376 *
377 * This functions inserts an already set-up &drm_mm_node into the allocator,
378 * meaning that start, size and color must be set by the caller. All other
379 * fields must be cleared to 0. This is useful to initialize the allocator with
380 * preallocated objects which must be set-up before the range allocator can be
381 * set-up, e.g. when taking over a firmware framebuffer.
382 *
383 * Returns:
384 * 0 on success, -ENOSPC if there's no hole where @node is.
385 */
386int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
387{
388 u64 end = node->start + node->size;
389 struct drm_mm_node *hole;
390 u64 hole_start, hole_end;
391 u64 adj_start, adj_end;
392
393 end = node->start + node->size;
394 if (unlikely(end <= node->start))
395 return -ENOSPC;
396
397 /* Find the relevant hole to add our node to */
398 hole = find_hole(mm, node->start);
399 if (!hole)
400 return -ENOSPC;
401
402 adj_start = hole_start = __drm_mm_hole_node_start(hole);
403 adj_end = hole_end = hole_start + hole->hole_size;
404
405 if (mm->color_adjust)
406 mm->color_adjust(hole, node->color, &adj_start, &adj_end);
407
408 if (adj_start > node->start || adj_end < end)
409 return -ENOSPC;
410
411 node->mm = mm;
412
413 list_add(&node->node_list, &hole->node_list);
414 drm_mm_interval_tree_add_node(hole, node);
415 node->allocated = true;
416 node->hole_size = 0;
417
418 rm_hole(hole);
419 if (node->start > hole_start)
420 add_hole(hole);
421 if (end < hole_end)
422 add_hole(node);
423
424 save_stack(node);
425 return 0;
426}
427EXPORT_SYMBOL(drm_mm_reserve_node);
428
429/**
430 * drm_mm_insert_node_in_range - ranged search for space and insert @node
431 * @mm: drm_mm to allocate from
432 * @node: preallocate node to insert
433 * @size: size of the allocation
434 * @alignment: alignment of the allocation
435 * @color: opaque tag value to use for this node
436 * @range_start: start of the allowed range for this node
437 * @range_end: end of the allowed range for this node
438 * @mode: fine-tune the allocation search and placement
439 *
440 * The preallocated @node must be cleared to 0.
441 *
442 * Returns:
443 * 0 on success, -ENOSPC if there's no suitable hole.
444 */
445int drm_mm_insert_node_in_range(struct drm_mm * const mm,
446 struct drm_mm_node * const node,
447 u64 size, u64 alignment,
448 unsigned long color,
449 u64 range_start, u64 range_end,
450 enum drm_mm_insert_mode mode)
451{
452 struct drm_mm_node *hole;
453 u64 remainder_mask;
454
455 DRM_MM_BUG_ON(range_start >= range_end);
456
457 if (unlikely(size == 0 || range_end - range_start < size))
458 return -ENOSPC;
459
460 if (alignment <= 1)
461 alignment = 0;
462
463 remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
464 for (hole = first_hole(mm, range_start, range_end, size, mode); hole;
465 hole = next_hole(mm, hole, mode)) {
466 u64 hole_start = __drm_mm_hole_node_start(hole);
467 u64 hole_end = hole_start + hole->hole_size;
468 u64 adj_start, adj_end;
469 u64 col_start, col_end;
470
471 if (mode == DRM_MM_INSERT_LOW && hole_start >= range_end)
472 break;
473
474 if (mode == DRM_MM_INSERT_HIGH && hole_end <= range_start)
475 break;
476
477 col_start = hole_start;
478 col_end = hole_end;
479 if (mm->color_adjust)
480 mm->color_adjust(hole, color, &col_start, &col_end);
481
482 adj_start = max(col_start, range_start);
483 adj_end = min(col_end, range_end);
484
485 if (adj_end <= adj_start || adj_end - adj_start < size)
486 continue;
487
488 if (mode == DRM_MM_INSERT_HIGH)
489 adj_start = adj_end - size;
490
491 if (alignment) {
492 u64 rem;
493
494 if (likely(remainder_mask))
495 rem = adj_start & remainder_mask;
496 else
497 div64_u64_rem(adj_start, alignment, &rem);
498 if (rem) {
499 adj_start -= rem;
500 if (mode != DRM_MM_INSERT_HIGH)
501 adj_start += alignment;
502
503 if (adj_start < max(col_start, range_start) ||
504 min(col_end, range_end) - adj_start < size)
505 continue;
506
507 if (adj_end <= adj_start ||
508 adj_end - adj_start < size)
509 continue;
510 }
511 }
512
513 node->mm = mm;
514 node->size = size;
515 node->start = adj_start;
516 node->color = color;
517 node->hole_size = 0;
518
519 list_add(&node->node_list, &hole->node_list);
520 drm_mm_interval_tree_add_node(hole, node);
521 node->allocated = true;
522
523 rm_hole(hole);
524 if (adj_start > hole_start)
525 add_hole(hole);
526 if (adj_start + size < hole_end)
527 add_hole(node);
528
529 save_stack(node);
530 return 0;
531 }
532
533 return -ENOSPC;
534}
535EXPORT_SYMBOL(drm_mm_insert_node_in_range);
536
537/**
538 * drm_mm_remove_node - Remove a memory node from the allocator.
539 * @node: drm_mm_node to remove
540 *
541 * This just removes a node from its drm_mm allocator. The node does not need to
542 * be cleared again before it can be re-inserted into this or any other drm_mm
543 * allocator. It is a bug to call this function on a unallocated node.
544 */
545void drm_mm_remove_node(struct drm_mm_node *node)
546{
547 struct drm_mm *mm = node->mm;
548 struct drm_mm_node *prev_node;
549
550 DRM_MM_BUG_ON(!node->allocated);
551 DRM_MM_BUG_ON(node->scanned_block);
552
553 prev_node = list_prev_entry(node, node_list);
554
555 if (drm_mm_hole_follows(node))
556 rm_hole(node);
557
558 drm_mm_interval_tree_remove(node, &mm->interval_tree);
559 list_del(&node->node_list);
560 node->allocated = false;
561
562 if (drm_mm_hole_follows(prev_node))
563 rm_hole(prev_node);
564 add_hole(prev_node);
565}
566EXPORT_SYMBOL(drm_mm_remove_node);
567
568/**
569 * drm_mm_replace_node - move an allocation from @old to @new
570 * @old: drm_mm_node to remove from the allocator
571 * @new: drm_mm_node which should inherit @old's allocation
572 *
573 * This is useful for when drivers embed the drm_mm_node structure and hence
574 * can't move allocations by reassigning pointers. It's a combination of remove
575 * and insert with the guarantee that the allocation start will match.
576 */
577void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
578{
579 struct drm_mm *mm = old->mm;
580
581 DRM_MM_BUG_ON(!old->allocated);
582
583 *new = *old;
584
585 list_replace(&old->node_list, &new->node_list);
586 rb_replace_node_cached(&old->rb, &new->rb, &mm->interval_tree);
587
588 if (drm_mm_hole_follows(old)) {
589 list_replace(&old->hole_stack, &new->hole_stack);
590 rb_replace_node(&old->rb_hole_size,
591 &new->rb_hole_size,
592 &mm->holes_size);
593 rb_replace_node(&old->rb_hole_addr,
594 &new->rb_hole_addr,
595 &mm->holes_addr);
596 }
597
598 old->allocated = false;
599 new->allocated = true;
600}
601EXPORT_SYMBOL(drm_mm_replace_node);
602
603/**
604 * DOC: lru scan roster
605 *
606 * Very often GPUs need to have continuous allocations for a given object. When
607 * evicting objects to make space for a new one it is therefore not most
608 * efficient when we simply start to select all objects from the tail of an LRU
609 * until there's a suitable hole: Especially for big objects or nodes that
610 * otherwise have special allocation constraints there's a good chance we evict
611 * lots of (smaller) objects unnecessarily.
612 *
613 * The DRM range allocator supports this use-case through the scanning
614 * interfaces. First a scan operation needs to be initialized with
615 * drm_mm_scan_init() or drm_mm_scan_init_with_range(). The driver adds
616 * objects to the roster, probably by walking an LRU list, but this can be
617 * freely implemented. Eviction candiates are added using
618 * drm_mm_scan_add_block() until a suitable hole is found or there are no
619 * further evictable objects. Eviction roster metadata is tracked in &struct
620 * drm_mm_scan.
621 *
622 * The driver must walk through all objects again in exactly the reverse
623 * order to restore the allocator state. Note that while the allocator is used
624 * in the scan mode no other operation is allowed.
625 *
626 * Finally the driver evicts all objects selected (drm_mm_scan_remove_block()
627 * reported true) in the scan, and any overlapping nodes after color adjustment
628 * (drm_mm_scan_color_evict()). Adding and removing an object is O(1), and
629 * since freeing a node is also O(1) the overall complexity is
630 * O(scanned_objects). So like the free stack which needs to be walked before a
631 * scan operation even begins this is linear in the number of objects. It
632 * doesn't seem to hurt too badly.
633 */
634
635/**
636 * drm_mm_scan_init_with_range - initialize range-restricted lru scanning
637 * @scan: scan state
638 * @mm: drm_mm to scan
639 * @size: size of the allocation
640 * @alignment: alignment of the allocation
641 * @color: opaque tag value to use for the allocation
642 * @start: start of the allowed range for the allocation
643 * @end: end of the allowed range for the allocation
644 * @mode: fine-tune the allocation search and placement
645 *
646 * This simply sets up the scanning routines with the parameters for the desired
647 * hole.
648 *
649 * Warning:
650 * As long as the scan list is non-empty, no other operations than
651 * adding/removing nodes to/from the scan list are allowed.
652 */
653void drm_mm_scan_init_with_range(struct drm_mm_scan *scan,
654 struct drm_mm *mm,
655 u64 size,
656 u64 alignment,
657 unsigned long color,
658 u64 start,
659 u64 end,
660 enum drm_mm_insert_mode mode)
661{
662 DRM_MM_BUG_ON(start >= end);
663 DRM_MM_BUG_ON(!size || size > end - start);
664 DRM_MM_BUG_ON(mm->scan_active);
665
666 scan->mm = mm;
667
668 if (alignment <= 1)
669 alignment = 0;
670
671 scan->color = color;
672 scan->alignment = alignment;
673 scan->remainder_mask = is_power_of_2(alignment) ? alignment - 1 : 0;
674 scan->size = size;
675 scan->mode = mode;
676
677 DRM_MM_BUG_ON(end <= start);
678 scan->range_start = start;
679 scan->range_end = end;
680
681 scan->hit_start = U64_MAX;
682 scan->hit_end = 0;
683}
684EXPORT_SYMBOL(drm_mm_scan_init_with_range);
685
686/**
687 * drm_mm_scan_add_block - add a node to the scan list
688 * @scan: the active drm_mm scanner
689 * @node: drm_mm_node to add
690 *
691 * Add a node to the scan list that might be freed to make space for the desired
692 * hole.
693 *
694 * Returns:
695 * True if a hole has been found, false otherwise.
696 */
697bool drm_mm_scan_add_block(struct drm_mm_scan *scan,
698 struct drm_mm_node *node)
699{
700 struct drm_mm *mm = scan->mm;
701 struct drm_mm_node *hole;
702 u64 hole_start, hole_end;
703 u64 col_start, col_end;
704 u64 adj_start, adj_end;
705
706 DRM_MM_BUG_ON(node->mm != mm);
707 DRM_MM_BUG_ON(!node->allocated);
708 DRM_MM_BUG_ON(node->scanned_block);
709 node->scanned_block = true;
710 mm->scan_active++;
711
712 /* Remove this block from the node_list so that we enlarge the hole
713 * (distance between the end of our previous node and the start of
714 * or next), without poisoning the link so that we can restore it
715 * later in drm_mm_scan_remove_block().
716 */
717 hole = list_prev_entry(node, node_list);
718 DRM_MM_BUG_ON(list_next_entry(hole, node_list) != node);
719 __list_del_entry(&node->node_list);
720
721 hole_start = __drm_mm_hole_node_start(hole);
722 hole_end = __drm_mm_hole_node_end(hole);
723
724 col_start = hole_start;
725 col_end = hole_end;
726 if (mm->color_adjust)
727 mm->color_adjust(hole, scan->color, &col_start, &col_end);
728
729 adj_start = max(col_start, scan->range_start);
730 adj_end = min(col_end, scan->range_end);
731 if (adj_end <= adj_start || adj_end - adj_start < scan->size)
732 return false;
733
734 if (scan->mode == DRM_MM_INSERT_HIGH)
735 adj_start = adj_end - scan->size;
736
737 if (scan->alignment) {
738 u64 rem;
739
740 if (likely(scan->remainder_mask))
741 rem = adj_start & scan->remainder_mask;
742 else
743 div64_u64_rem(adj_start, scan->alignment, &rem);
744 if (rem) {
745 adj_start -= rem;
746 if (scan->mode != DRM_MM_INSERT_HIGH)
747 adj_start += scan->alignment;
748 if (adj_start < max(col_start, scan->range_start) ||
749 min(col_end, scan->range_end) - adj_start < scan->size)
750 return false;
751
752 if (adj_end <= adj_start ||
753 adj_end - adj_start < scan->size)
754 return false;
755 }
756 }
757
758 scan->hit_start = adj_start;
759 scan->hit_end = adj_start + scan->size;
760
761 DRM_MM_BUG_ON(scan->hit_start >= scan->hit_end);
762 DRM_MM_BUG_ON(scan->hit_start < hole_start);
763 DRM_MM_BUG_ON(scan->hit_end > hole_end);
764
765 return true;
766}
767EXPORT_SYMBOL(drm_mm_scan_add_block);
768
769/**
770 * drm_mm_scan_remove_block - remove a node from the scan list
771 * @scan: the active drm_mm scanner
772 * @node: drm_mm_node to remove
773 *
774 * Nodes **must** be removed in exactly the reverse order from the scan list as
775 * they have been added (e.g. using list_add() as they are added and then
776 * list_for_each() over that eviction list to remove), otherwise the internal
777 * state of the memory manager will be corrupted.
778 *
779 * When the scan list is empty, the selected memory nodes can be freed. An
780 * immediately following drm_mm_insert_node_in_range_generic() or one of the
781 * simpler versions of that function with !DRM_MM_SEARCH_BEST will then return
782 * the just freed block (because its at the top of the free_stack list).
783 *
784 * Returns:
785 * True if this block should be evicted, false otherwise. Will always
786 * return false when no hole has been found.
787 */
788bool drm_mm_scan_remove_block(struct drm_mm_scan *scan,
789 struct drm_mm_node *node)
790{
791 struct drm_mm_node *prev_node;
792
793 DRM_MM_BUG_ON(node->mm != scan->mm);
794 DRM_MM_BUG_ON(!node->scanned_block);
795 node->scanned_block = false;
796
797 DRM_MM_BUG_ON(!node->mm->scan_active);
798 node->mm->scan_active--;
799
800 /* During drm_mm_scan_add_block() we decoupled this node leaving
801 * its pointers intact. Now that the caller is walking back along
802 * the eviction list we can restore this block into its rightful
803 * place on the full node_list. To confirm that the caller is walking
804 * backwards correctly we check that prev_node->next == node->next,
805 * i.e. both believe the same node should be on the other side of the
806 * hole.
807 */
808 prev_node = list_prev_entry(node, node_list);
809 DRM_MM_BUG_ON(list_next_entry(prev_node, node_list) !=
810 list_next_entry(node, node_list));
811 list_add(&node->node_list, &prev_node->node_list);
812
813 return (node->start + node->size > scan->hit_start &&
814 node->start < scan->hit_end);
815}
816EXPORT_SYMBOL(drm_mm_scan_remove_block);
817
818/**
819 * drm_mm_scan_color_evict - evict overlapping nodes on either side of hole
820 * @scan: drm_mm scan with target hole
821 *
822 * After completing an eviction scan and removing the selected nodes, we may
823 * need to remove a few more nodes from either side of the target hole if
824 * mm.color_adjust is being used.
825 *
826 * Returns:
827 * A node to evict, or NULL if there are no overlapping nodes.
828 */
829struct drm_mm_node *drm_mm_scan_color_evict(struct drm_mm_scan *scan)
830{
831 struct drm_mm *mm = scan->mm;
832 struct drm_mm_node *hole;
833 u64 hole_start, hole_end;
834
835 DRM_MM_BUG_ON(list_empty(&mm->hole_stack));
836
837 if (!mm->color_adjust)
838 return NULL;
839
840 /*
841 * The hole found during scanning should ideally be the first element
842 * in the hole_stack list, but due to side-effects in the driver it
843 * may not be.
844 */
845 list_for_each_entry(hole, &mm->hole_stack, hole_stack) {
846 hole_start = __drm_mm_hole_node_start(hole);
847 hole_end = hole_start + hole->hole_size;
848
849 if (hole_start <= scan->hit_start &&
850 hole_end >= scan->hit_end)
851 break;
852 }
853
854 /* We should only be called after we found the hole previously */
855 DRM_MM_BUG_ON(&hole->hole_stack == &mm->hole_stack);
856 if (unlikely(&hole->hole_stack == &mm->hole_stack))
857 return NULL;
858
859 DRM_MM_BUG_ON(hole_start > scan->hit_start);
860 DRM_MM_BUG_ON(hole_end < scan->hit_end);
861
862 mm->color_adjust(hole, scan->color, &hole_start, &hole_end);
863 if (hole_start > scan->hit_start)
864 return hole;
865 if (hole_end < scan->hit_end)
866 return list_next_entry(hole, node_list);
867
868 return NULL;
869}
870EXPORT_SYMBOL(drm_mm_scan_color_evict);
871
872/**
873 * drm_mm_init - initialize a drm-mm allocator
874 * @mm: the drm_mm structure to initialize
875 * @start: start of the range managed by @mm
876 * @size: end of the range managed by @mm
877 *
878 * Note that @mm must be cleared to 0 before calling this function.
879 */
880void drm_mm_init(struct drm_mm *mm, u64 start, u64 size)
881{
882 DRM_MM_BUG_ON(start + size <= start);
883
884 mm->color_adjust = NULL;
885
886 INIT_LIST_HEAD(&mm->hole_stack);
887 mm->interval_tree = RB_ROOT_CACHED;
888 mm->holes_size = RB_ROOT;
889 mm->holes_addr = RB_ROOT;
890
891 /* Clever trick to avoid a special case in the free hole tracking. */
892 INIT_LIST_HEAD(&mm->head_node.node_list);
893 mm->head_node.allocated = false;
894 mm->head_node.mm = mm;
895 mm->head_node.start = start + size;
896 mm->head_node.size = -size;
897 add_hole(&mm->head_node);
898
899 mm->scan_active = 0;
900}
901EXPORT_SYMBOL(drm_mm_init);
902
903/**
904 * drm_mm_takedown - clean up a drm_mm allocator
905 * @mm: drm_mm allocator to clean up
906 *
907 * Note that it is a bug to call this function on an allocator which is not
908 * clean.
909 */
910void drm_mm_takedown(struct drm_mm *mm)
911{
912 if (WARN(!drm_mm_clean(mm),
913 "Memory manager not clean during takedown.\n"))
914 show_leaks(mm);
915}
916EXPORT_SYMBOL(drm_mm_takedown);
917
918static u64 drm_mm_dump_hole(struct drm_printer *p, const struct drm_mm_node *entry)
919{
920 u64 start, size;
921
922 size = entry->hole_size;
923 if (size) {
924 start = drm_mm_hole_node_start(entry);
925 drm_printf(p, "%#018llx-%#018llx: %llu: free\n",
926 start, start + size, size);
927 }
928
929 return size;
930}
931/**
932 * drm_mm_print - print allocator state
933 * @mm: drm_mm allocator to print
934 * @p: DRM printer to use
935 */
936void drm_mm_print(const struct drm_mm *mm, struct drm_printer *p)
937{
938 const struct drm_mm_node *entry;
939 u64 total_used = 0, total_free = 0, total = 0;
940
941 total_free += drm_mm_dump_hole(p, &mm->head_node);
942
943 drm_mm_for_each_node(entry, mm) {
944 drm_printf(p, "%#018llx-%#018llx: %llu: used\n", entry->start,
945 entry->start + entry->size, entry->size);
946 total_used += entry->size;
947 total_free += drm_mm_dump_hole(p, entry);
948 }
949 total = total_free + total_used;
950
951 drm_printf(p, "total: %llu, used %llu free %llu\n", total,
952 total_used, total_free);
953}
954EXPORT_SYMBOL(drm_mm_print);