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1/**************************************************************************
2 *
3 * Copyright (c) 2006-2009 Vmware, Inc., Palo Alto, CA., USA
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27/*
28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
29 */
30#ifndef _TTM_BO_DRIVER_H_
31#define _TTM_BO_DRIVER_H_
32
33#include <drm/drm_mm.h>
34#include <drm/drm_vma_manager.h>
35#include <linux/workqueue.h>
36#include <linux/fs.h>
37#include <linux/spinlock.h>
38#include <linux/dma-resv.h>
39
40#include "ttm_bo_api.h"
41#include "ttm_memory.h"
42#include "ttm_module.h"
43#include "ttm_placement.h"
44#include "ttm_tt.h"
45
46#define TTM_MAX_BO_PRIORITY 4U
47
48#define TTM_MEMTYPE_FLAG_FIXED (1 << 0) /* Fixed (on-card) PCI memory */
49#define TTM_MEMTYPE_FLAG_MAPPABLE (1 << 1) /* Memory mappable */
50#define TTM_MEMTYPE_FLAG_CMA (1 << 3) /* Can't map aperture */
51
52struct ttm_mem_type_manager;
53
54struct ttm_mem_type_manager_func {
55 /**
56 * struct ttm_mem_type_manager member init
57 *
58 * @man: Pointer to a memory type manager.
59 * @p_size: Implementation dependent, but typically the size of the
60 * range to be managed in pages.
61 *
62 * Called to initialize a private range manager. The function is
63 * expected to initialize the man::priv member.
64 * Returns 0 on success, negative error code on failure.
65 */
66 int (*init)(struct ttm_mem_type_manager *man, unsigned long p_size);
67
68 /**
69 * struct ttm_mem_type_manager member takedown
70 *
71 * @man: Pointer to a memory type manager.
72 *
73 * Called to undo the setup done in init. All allocated resources
74 * should be freed.
75 */
76 int (*takedown)(struct ttm_mem_type_manager *man);
77
78 /**
79 * struct ttm_mem_type_manager member get_node
80 *
81 * @man: Pointer to a memory type manager.
82 * @bo: Pointer to the buffer object we're allocating space for.
83 * @placement: Placement details.
84 * @flags: Additional placement flags.
85 * @mem: Pointer to a struct ttm_mem_reg to be filled in.
86 *
87 * This function should allocate space in the memory type managed
88 * by @man. Placement details if
89 * applicable are given by @placement. If successful,
90 * @mem::mm_node should be set to a non-null value, and
91 * @mem::start should be set to a value identifying the beginning
92 * of the range allocated, and the function should return zero.
93 * If the memory region accommodate the buffer object, @mem::mm_node
94 * should be set to NULL, and the function should return 0.
95 * If a system error occurred, preventing the request to be fulfilled,
96 * the function should return a negative error code.
97 *
98 * Note that @mem::mm_node will only be dereferenced by
99 * struct ttm_mem_type_manager functions and optionally by the driver,
100 * which has knowledge of the underlying type.
101 *
102 * This function may not be called from within atomic context, so
103 * an implementation can and must use either a mutex or a spinlock to
104 * protect any data structures managing the space.
105 */
106 int (*get_node)(struct ttm_mem_type_manager *man,
107 struct ttm_buffer_object *bo,
108 const struct ttm_place *place,
109 struct ttm_mem_reg *mem);
110
111 /**
112 * struct ttm_mem_type_manager member put_node
113 *
114 * @man: Pointer to a memory type manager.
115 * @mem: Pointer to a struct ttm_mem_reg to be filled in.
116 *
117 * This function frees memory type resources previously allocated
118 * and that are identified by @mem::mm_node and @mem::start. May not
119 * be called from within atomic context.
120 */
121 void (*put_node)(struct ttm_mem_type_manager *man,
122 struct ttm_mem_reg *mem);
123
124 /**
125 * struct ttm_mem_type_manager member debug
126 *
127 * @man: Pointer to a memory type manager.
128 * @printer: Prefix to be used in printout to identify the caller.
129 *
130 * This function is called to print out the state of the memory
131 * type manager to aid debugging of out-of-memory conditions.
132 * It may not be called from within atomic context.
133 */
134 void (*debug)(struct ttm_mem_type_manager *man,
135 struct drm_printer *printer);
136};
137
138/**
139 * struct ttm_mem_type_manager
140 *
141 * @has_type: The memory type has been initialized.
142 * @use_type: The memory type is enabled.
143 * @flags: TTM_MEMTYPE_XX flags identifying the traits of the memory
144 * managed by this memory type.
145 * @gpu_offset: If used, the GPU offset of the first managed page of
146 * fixed memory or the first managed location in an aperture.
147 * @size: Size of the managed region.
148 * @available_caching: A mask of available caching types, TTM_PL_FLAG_XX,
149 * as defined in ttm_placement_common.h
150 * @default_caching: The default caching policy used for a buffer object
151 * placed in this memory type if the user doesn't provide one.
152 * @func: structure pointer implementing the range manager. See above
153 * @priv: Driver private closure for @func.
154 * @io_reserve_mutex: Mutex optionally protecting shared io_reserve structures
155 * @use_io_reserve_lru: Use an lru list to try to unreserve io_mem_regions
156 * reserved by the TTM vm system.
157 * @io_reserve_lru: Optional lru list for unreserving io mem regions.
158 * @io_reserve_fastpath: Only use bdev::driver::io_mem_reserve to obtain
159 * @move_lock: lock for move fence
160 * static information. bdev::driver::io_mem_free is never used.
161 * @lru: The lru list for this memory type.
162 * @move: The fence of the last pipelined move operation.
163 *
164 * This structure is used to identify and manage memory types for a device.
165 * It's set up by the ttm_bo_driver::init_mem_type method.
166 */
167
168
169
170struct ttm_mem_type_manager {
171 struct ttm_bo_device *bdev;
172
173 /*
174 * No protection. Constant from start.
175 */
176
177 bool has_type;
178 bool use_type;
179 uint32_t flags;
180 uint64_t gpu_offset; /* GPU address space is independent of CPU word size */
181 uint64_t size;
182 uint32_t available_caching;
183 uint32_t default_caching;
184 const struct ttm_mem_type_manager_func *func;
185 void *priv;
186 struct mutex io_reserve_mutex;
187 bool use_io_reserve_lru;
188 bool io_reserve_fastpath;
189 spinlock_t move_lock;
190
191 /*
192 * Protected by @io_reserve_mutex:
193 */
194
195 struct list_head io_reserve_lru;
196
197 /*
198 * Protected by the global->lru_lock.
199 */
200
201 struct list_head lru[TTM_MAX_BO_PRIORITY];
202
203 /*
204 * Protected by @move_lock.
205 */
206 struct dma_fence *move;
207};
208
209/**
210 * struct ttm_bo_driver
211 *
212 * @create_ttm_backend_entry: Callback to create a struct ttm_backend.
213 * @invalidate_caches: Callback to invalidate read caches when a buffer object
214 * has been evicted.
215 * @init_mem_type: Callback to initialize a struct ttm_mem_type_manager
216 * structure.
217 * @evict_flags: Callback to obtain placement flags when a buffer is evicted.
218 * @move: Callback for a driver to hook in accelerated functions to
219 * move a buffer.
220 * If set to NULL, a potentially slow memcpy() move is used.
221 */
222
223struct ttm_bo_driver {
224 /**
225 * ttm_tt_create
226 *
227 * @bo: The buffer object to create the ttm for.
228 * @page_flags: Page flags as identified by TTM_PAGE_FLAG_XX flags.
229 *
230 * Create a struct ttm_tt to back data with system memory pages.
231 * No pages are actually allocated.
232 * Returns:
233 * NULL: Out of memory.
234 */
235 struct ttm_tt *(*ttm_tt_create)(struct ttm_buffer_object *bo,
236 uint32_t page_flags);
237
238 /**
239 * ttm_tt_populate
240 *
241 * @ttm: The struct ttm_tt to contain the backing pages.
242 *
243 * Allocate all backing pages
244 * Returns:
245 * -ENOMEM: Out of memory.
246 */
247 int (*ttm_tt_populate)(struct ttm_tt *ttm,
248 struct ttm_operation_ctx *ctx);
249
250 /**
251 * ttm_tt_unpopulate
252 *
253 * @ttm: The struct ttm_tt to contain the backing pages.
254 *
255 * Free all backing page
256 */
257 void (*ttm_tt_unpopulate)(struct ttm_tt *ttm);
258
259 /**
260 * struct ttm_bo_driver member invalidate_caches
261 *
262 * @bdev: the buffer object device.
263 * @flags: new placement of the rebound buffer object.
264 *
265 * A previosly evicted buffer has been rebound in a
266 * potentially new location. Tell the driver that it might
267 * consider invalidating read (texture) caches on the next command
268 * submission as a consequence.
269 */
270
271 int (*invalidate_caches)(struct ttm_bo_device *bdev, uint32_t flags);
272 int (*init_mem_type)(struct ttm_bo_device *bdev, uint32_t type,
273 struct ttm_mem_type_manager *man);
274
275 /**
276 * struct ttm_bo_driver member eviction_valuable
277 *
278 * @bo: the buffer object to be evicted
279 * @place: placement we need room for
280 *
281 * Check with the driver if it is valuable to evict a BO to make room
282 * for a certain placement.
283 */
284 bool (*eviction_valuable)(struct ttm_buffer_object *bo,
285 const struct ttm_place *place);
286 /**
287 * struct ttm_bo_driver member evict_flags:
288 *
289 * @bo: the buffer object to be evicted
290 *
291 * Return the bo flags for a buffer which is not mapped to the hardware.
292 * These will be placed in proposed_flags so that when the move is
293 * finished, they'll end up in bo->mem.flags
294 */
295
296 void (*evict_flags)(struct ttm_buffer_object *bo,
297 struct ttm_placement *placement);
298
299 /**
300 * struct ttm_bo_driver member move:
301 *
302 * @bo: the buffer to move
303 * @evict: whether this motion is evicting the buffer from
304 * the graphics address space
305 * @ctx: context for this move with parameters
306 * @new_mem: the new memory region receiving the buffer
307 *
308 * Move a buffer between two memory regions.
309 */
310 int (*move)(struct ttm_buffer_object *bo, bool evict,
311 struct ttm_operation_ctx *ctx,
312 struct ttm_mem_reg *new_mem);
313
314 /**
315 * struct ttm_bo_driver_member verify_access
316 *
317 * @bo: Pointer to a buffer object.
318 * @filp: Pointer to a struct file trying to access the object.
319 *
320 * Called from the map / write / read methods to verify that the
321 * caller is permitted to access the buffer object.
322 * This member may be set to NULL, which will refuse this kind of
323 * access for all buffer objects.
324 * This function should return 0 if access is granted, -EPERM otherwise.
325 */
326 int (*verify_access)(struct ttm_buffer_object *bo,
327 struct file *filp);
328
329 /**
330 * Hook to notify driver about a driver move so it
331 * can do tiling things and book-keeping.
332 *
333 * @evict: whether this move is evicting the buffer from the graphics
334 * address space
335 */
336 void (*move_notify)(struct ttm_buffer_object *bo,
337 bool evict,
338 struct ttm_mem_reg *new_mem);
339 /* notify the driver we are taking a fault on this BO
340 * and have reserved it */
341 int (*fault_reserve_notify)(struct ttm_buffer_object *bo);
342
343 /**
344 * notify the driver that we're about to swap out this bo
345 */
346 void (*swap_notify)(struct ttm_buffer_object *bo);
347
348 /**
349 * Driver callback on when mapping io memory (for bo_move_memcpy
350 * for instance). TTM will take care to call io_mem_free whenever
351 * the mapping is not use anymore. io_mem_reserve & io_mem_free
352 * are balanced.
353 */
354 int (*io_mem_reserve)(struct ttm_bo_device *bdev,
355 struct ttm_mem_reg *mem);
356 void (*io_mem_free)(struct ttm_bo_device *bdev,
357 struct ttm_mem_reg *mem);
358
359 /**
360 * Return the pfn for a given page_offset inside the BO.
361 *
362 * @bo: the BO to look up the pfn for
363 * @page_offset: the offset to look up
364 */
365 unsigned long (*io_mem_pfn)(struct ttm_buffer_object *bo,
366 unsigned long page_offset);
367
368 /**
369 * Read/write memory buffers for ptrace access
370 *
371 * @bo: the BO to access
372 * @offset: the offset from the start of the BO
373 * @buf: pointer to source/destination buffer
374 * @len: number of bytes to copy
375 * @write: whether to read (0) from or write (non-0) to BO
376 *
377 * If successful, this function should return the number of
378 * bytes copied, -EIO otherwise. If the number of bytes
379 * returned is < len, the function may be called again with
380 * the remainder of the buffer to copy.
381 */
382 int (*access_memory)(struct ttm_buffer_object *bo, unsigned long offset,
383 void *buf, int len, int write);
384
385 /**
386 * struct ttm_bo_driver member del_from_lru_notify
387 *
388 * @bo: the buffer object deleted from lru
389 *
390 * notify driver that a BO was deleted from LRU.
391 */
392 void (*del_from_lru_notify)(struct ttm_buffer_object *bo);
393
394 /**
395 * Notify the driver that we're about to release a BO
396 *
397 * @bo: BO that is about to be released
398 *
399 * Gives the driver a chance to do any cleanup, including
400 * adding fences that may force a delayed delete
401 */
402 void (*release_notify)(struct ttm_buffer_object *bo);
403};
404
405/**
406 * struct ttm_bo_global - Buffer object driver global data.
407 *
408 * @mem_glob: Pointer to a struct ttm_mem_global object for accounting.
409 * @dummy_read_page: Pointer to a dummy page used for mapping requests
410 * of unpopulated pages.
411 * @shrink: A shrink callback object used for buffer object swap.
412 * @device_list_mutex: Mutex protecting the device list.
413 * This mutex is held while traversing the device list for pm options.
414 * @lru_lock: Spinlock protecting the bo subsystem lru lists.
415 * @device_list: List of buffer object devices.
416 * @swap_lru: Lru list of buffer objects used for swapping.
417 */
418
419extern struct ttm_bo_global {
420
421 /**
422 * Constant after init.
423 */
424
425 struct kobject kobj;
426 struct ttm_mem_global *mem_glob;
427 struct page *dummy_read_page;
428 spinlock_t lru_lock;
429
430 /**
431 * Protected by ttm_global_mutex.
432 */
433 struct list_head device_list;
434
435 /**
436 * Protected by the lru_lock.
437 */
438 struct list_head swap_lru[TTM_MAX_BO_PRIORITY];
439
440 /**
441 * Internal protection.
442 */
443 atomic_t bo_count;
444} ttm_bo_glob;
445
446
447#define TTM_NUM_MEM_TYPES 8
448
449/**
450 * struct ttm_bo_device - Buffer object driver device-specific data.
451 *
452 * @driver: Pointer to a struct ttm_bo_driver struct setup by the driver.
453 * @man: An array of mem_type_managers.
454 * @vma_manager: Address space manager
455 * lru_lock: Spinlock that protects the buffer+device lru lists and
456 * ddestroy lists.
457 * @dev_mapping: A pointer to the struct address_space representing the
458 * device address space.
459 * @wq: Work queue structure for the delayed delete workqueue.
460 * @no_retry: Don't retry allocation if it fails
461 *
462 */
463
464struct ttm_bo_device {
465
466 /*
467 * Constant after bo device init / atomic.
468 */
469 struct list_head device_list;
470 struct ttm_bo_global *glob;
471 struct ttm_bo_driver *driver;
472 struct ttm_mem_type_manager man[TTM_NUM_MEM_TYPES];
473
474 /*
475 * Protected by internal locks.
476 */
477 struct drm_vma_offset_manager vma_manager;
478
479 /*
480 * Protected by the global:lru lock.
481 */
482 struct list_head ddestroy;
483
484 /*
485 * Protected by load / firstopen / lastclose /unload sync.
486 */
487
488 struct address_space *dev_mapping;
489
490 /*
491 * Internal protection.
492 */
493
494 struct delayed_work wq;
495
496 bool need_dma32;
497
498 bool no_retry;
499};
500
501/**
502 * struct ttm_lru_bulk_move_pos
503 *
504 * @first: first BO in the bulk move range
505 * @last: last BO in the bulk move range
506 *
507 * Positions for a lru bulk move.
508 */
509struct ttm_lru_bulk_move_pos {
510 struct ttm_buffer_object *first;
511 struct ttm_buffer_object *last;
512};
513
514/**
515 * struct ttm_lru_bulk_move
516 *
517 * @tt: first/last lru entry for BOs in the TT domain
518 * @vram: first/last lru entry for BOs in the VRAM domain
519 * @swap: first/last lru entry for BOs on the swap list
520 *
521 * Helper structure for bulk moves on the LRU list.
522 */
523struct ttm_lru_bulk_move {
524 struct ttm_lru_bulk_move_pos tt[TTM_MAX_BO_PRIORITY];
525 struct ttm_lru_bulk_move_pos vram[TTM_MAX_BO_PRIORITY];
526 struct ttm_lru_bulk_move_pos swap[TTM_MAX_BO_PRIORITY];
527};
528
529/**
530 * ttm_flag_masked
531 *
532 * @old: Pointer to the result and original value.
533 * @new: New value of bits.
534 * @mask: Mask of bits to change.
535 *
536 * Convenience function to change a number of bits identified by a mask.
537 */
538
539static inline uint32_t
540ttm_flag_masked(uint32_t *old, uint32_t new, uint32_t mask)
541{
542 *old ^= (*old ^ new) & mask;
543 return *old;
544}
545
546/*
547 * ttm_bo.c
548 */
549
550/**
551 * ttm_mem_reg_is_pci
552 *
553 * @bdev: Pointer to a struct ttm_bo_device.
554 * @mem: A valid struct ttm_mem_reg.
555 *
556 * Returns true if the memory described by @mem is PCI memory,
557 * false otherwise.
558 */
559bool ttm_mem_reg_is_pci(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem);
560
561/**
562 * ttm_bo_mem_space
563 *
564 * @bo: Pointer to a struct ttm_buffer_object. the data of which
565 * we want to allocate space for.
566 * @proposed_placement: Proposed new placement for the buffer object.
567 * @mem: A struct ttm_mem_reg.
568 * @interruptible: Sleep interruptible when sliping.
569 * @no_wait_gpu: Return immediately if the GPU is busy.
570 *
571 * Allocate memory space for the buffer object pointed to by @bo, using
572 * the placement flags in @mem, potentially evicting other idle buffer objects.
573 * This function may sleep while waiting for space to become available.
574 * Returns:
575 * -EBUSY: No space available (only if no_wait == 1).
576 * -ENOMEM: Could not allocate memory for the buffer object, either due to
577 * fragmentation or concurrent allocators.
578 * -ERESTARTSYS: An interruptible sleep was interrupted by a signal.
579 */
580int ttm_bo_mem_space(struct ttm_buffer_object *bo,
581 struct ttm_placement *placement,
582 struct ttm_mem_reg *mem,
583 struct ttm_operation_ctx *ctx);
584
585void ttm_bo_mem_put(struct ttm_buffer_object *bo, struct ttm_mem_reg *mem);
586void ttm_bo_mem_put_locked(struct ttm_buffer_object *bo,
587 struct ttm_mem_reg *mem);
588
589int ttm_bo_device_release(struct ttm_bo_device *bdev);
590
591/**
592 * ttm_bo_device_init
593 *
594 * @bdev: A pointer to a struct ttm_bo_device to initialize.
595 * @glob: A pointer to an initialized struct ttm_bo_global.
596 * @driver: A pointer to a struct ttm_bo_driver set up by the caller.
597 * @mapping: The address space to use for this bo.
598 * @file_page_offset: Offset into the device address space that is available
599 * for buffer data. This ensures compatibility with other users of the
600 * address space.
601 *
602 * Initializes a struct ttm_bo_device:
603 * Returns:
604 * !0: Failure.
605 */
606int ttm_bo_device_init(struct ttm_bo_device *bdev,
607 struct ttm_bo_driver *driver,
608 struct address_space *mapping,
609 bool need_dma32);
610
611/**
612 * ttm_bo_unmap_virtual
613 *
614 * @bo: tear down the virtual mappings for this BO
615 */
616void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo);
617
618/**
619 * ttm_bo_unmap_virtual
620 *
621 * @bo: tear down the virtual mappings for this BO
622 *
623 * The caller must take ttm_mem_io_lock before calling this function.
624 */
625void ttm_bo_unmap_virtual_locked(struct ttm_buffer_object *bo);
626
627int ttm_mem_io_reserve_vm(struct ttm_buffer_object *bo);
628void ttm_mem_io_free_vm(struct ttm_buffer_object *bo);
629int ttm_mem_io_lock(struct ttm_mem_type_manager *man, bool interruptible);
630void ttm_mem_io_unlock(struct ttm_mem_type_manager *man);
631
632void ttm_bo_del_sub_from_lru(struct ttm_buffer_object *bo);
633void ttm_bo_add_to_lru(struct ttm_buffer_object *bo);
634
635/**
636 * __ttm_bo_reserve:
637 *
638 * @bo: A pointer to a struct ttm_buffer_object.
639 * @interruptible: Sleep interruptible if waiting.
640 * @no_wait: Don't sleep while trying to reserve, rather return -EBUSY.
641 * @ticket: ticket used to acquire the ww_mutex.
642 *
643 * Will not remove reserved buffers from the lru lists.
644 * Otherwise identical to ttm_bo_reserve.
645 *
646 * Returns:
647 * -EDEADLK: The reservation may cause a deadlock.
648 * Release all buffer reservations, wait for @bo to become unreserved and
649 * try again. (only if use_sequence == 1).
650 * -ERESTARTSYS: A wait for the buffer to become unreserved was interrupted by
651 * a signal. Release all buffer reservations and return to user-space.
652 * -EBUSY: The function needed to sleep, but @no_wait was true
653 * -EALREADY: Bo already reserved using @ticket. This error code will only
654 * be returned if @use_ticket is set to true.
655 */
656static inline int __ttm_bo_reserve(struct ttm_buffer_object *bo,
657 bool interruptible, bool no_wait,
658 struct ww_acquire_ctx *ticket)
659{
660 int ret = 0;
661
662 if (no_wait) {
663 bool success;
664 if (WARN_ON(ticket))
665 return -EBUSY;
666
667 success = dma_resv_trylock(bo->base.resv);
668 return success ? 0 : -EBUSY;
669 }
670
671 if (interruptible)
672 ret = dma_resv_lock_interruptible(bo->base.resv, ticket);
673 else
674 ret = dma_resv_lock(bo->base.resv, ticket);
675 if (ret == -EINTR)
676 return -ERESTARTSYS;
677 return ret;
678}
679
680/**
681 * ttm_bo_reserve:
682 *
683 * @bo: A pointer to a struct ttm_buffer_object.
684 * @interruptible: Sleep interruptible if waiting.
685 * @no_wait: Don't sleep while trying to reserve, rather return -EBUSY.
686 * @ticket: ticket used to acquire the ww_mutex.
687 *
688 * Locks a buffer object for validation. (Or prevents other processes from
689 * locking it for validation) and removes it from lru lists, while taking
690 * a number of measures to prevent deadlocks.
691 *
692 * Deadlocks may occur when two processes try to reserve multiple buffers in
693 * different order, either by will or as a result of a buffer being evicted
694 * to make room for a buffer already reserved. (Buffers are reserved before
695 * they are evicted). The following algorithm prevents such deadlocks from
696 * occurring:
697 * Processes attempting to reserve multiple buffers other than for eviction,
698 * (typically execbuf), should first obtain a unique 32-bit
699 * validation sequence number,
700 * and call this function with @use_ticket == 1 and @ticket->stamp == the unique
701 * sequence number. If upon call of this function, the buffer object is already
702 * reserved, the validation sequence is checked against the validation
703 * sequence of the process currently reserving the buffer,
704 * and if the current validation sequence is greater than that of the process
705 * holding the reservation, the function returns -EDEADLK. Otherwise it sleeps
706 * waiting for the buffer to become unreserved, after which it retries
707 * reserving.
708 * The caller should, when receiving an -EDEADLK error
709 * release all its buffer reservations, wait for @bo to become unreserved, and
710 * then rerun the validation with the same validation sequence. This procedure
711 * will always guarantee that the process with the lowest validation sequence
712 * will eventually succeed, preventing both deadlocks and starvation.
713 *
714 * Returns:
715 * -EDEADLK: The reservation may cause a deadlock.
716 * Release all buffer reservations, wait for @bo to become unreserved and
717 * try again. (only if use_sequence == 1).
718 * -ERESTARTSYS: A wait for the buffer to become unreserved was interrupted by
719 * a signal. Release all buffer reservations and return to user-space.
720 * -EBUSY: The function needed to sleep, but @no_wait was true
721 * -EALREADY: Bo already reserved using @ticket. This error code will only
722 * be returned if @use_ticket is set to true.
723 */
724static inline int ttm_bo_reserve(struct ttm_buffer_object *bo,
725 bool interruptible, bool no_wait,
726 struct ww_acquire_ctx *ticket)
727{
728 int ret;
729
730 WARN_ON(!kref_read(&bo->kref));
731
732 ret = __ttm_bo_reserve(bo, interruptible, no_wait, ticket);
733 if (likely(ret == 0))
734 ttm_bo_del_sub_from_lru(bo);
735
736 return ret;
737}
738
739/**
740 * ttm_bo_reserve_slowpath:
741 * @bo: A pointer to a struct ttm_buffer_object.
742 * @interruptible: Sleep interruptible if waiting.
743 * @sequence: Set (@bo)->sequence to this value after lock
744 *
745 * This is called after ttm_bo_reserve returns -EAGAIN and we backed off
746 * from all our other reservations. Because there are no other reservations
747 * held by us, this function cannot deadlock any more.
748 */
749static inline int ttm_bo_reserve_slowpath(struct ttm_buffer_object *bo,
750 bool interruptible,
751 struct ww_acquire_ctx *ticket)
752{
753 int ret = 0;
754
755 WARN_ON(!kref_read(&bo->kref));
756
757 if (interruptible)
758 ret = dma_resv_lock_slow_interruptible(bo->base.resv,
759 ticket);
760 else
761 dma_resv_lock_slow(bo->base.resv, ticket);
762
763 if (likely(ret == 0))
764 ttm_bo_del_sub_from_lru(bo);
765 else if (ret == -EINTR)
766 ret = -ERESTARTSYS;
767
768 return ret;
769}
770
771/**
772 * ttm_bo_unreserve
773 *
774 * @bo: A pointer to a struct ttm_buffer_object.
775 *
776 * Unreserve a previous reservation of @bo.
777 */
778static inline void ttm_bo_unreserve(struct ttm_buffer_object *bo)
779{
780 spin_lock(&bo->bdev->glob->lru_lock);
781 if (list_empty(&bo->lru))
782 ttm_bo_add_to_lru(bo);
783 else
784 ttm_bo_move_to_lru_tail(bo, NULL);
785 spin_unlock(&bo->bdev->glob->lru_lock);
786 dma_resv_unlock(bo->base.resv);
787}
788
789/*
790 * ttm_bo_util.c
791 */
792
793int ttm_mem_io_reserve(struct ttm_bo_device *bdev,
794 struct ttm_mem_reg *mem);
795void ttm_mem_io_free(struct ttm_bo_device *bdev,
796 struct ttm_mem_reg *mem);
797/**
798 * ttm_bo_move_ttm
799 *
800 * @bo: A pointer to a struct ttm_buffer_object.
801 * @interruptible: Sleep interruptible if waiting.
802 * @no_wait_gpu: Return immediately if the GPU is busy.
803 * @new_mem: struct ttm_mem_reg indicating where to move.
804 *
805 * Optimized move function for a buffer object with both old and
806 * new placement backed by a TTM. The function will, if successful,
807 * free any old aperture space, and set (@new_mem)->mm_node to NULL,
808 * and update the (@bo)->mem placement flags. If unsuccessful, the old
809 * data remains untouched, and it's up to the caller to free the
810 * memory space indicated by @new_mem.
811 * Returns:
812 * !0: Failure.
813 */
814
815int ttm_bo_move_ttm(struct ttm_buffer_object *bo,
816 struct ttm_operation_ctx *ctx,
817 struct ttm_mem_reg *new_mem);
818
819/**
820 * ttm_bo_move_memcpy
821 *
822 * @bo: A pointer to a struct ttm_buffer_object.
823 * @interruptible: Sleep interruptible if waiting.
824 * @no_wait_gpu: Return immediately if the GPU is busy.
825 * @new_mem: struct ttm_mem_reg indicating where to move.
826 *
827 * Fallback move function for a mappable buffer object in mappable memory.
828 * The function will, if successful,
829 * free any old aperture space, and set (@new_mem)->mm_node to NULL,
830 * and update the (@bo)->mem placement flags. If unsuccessful, the old
831 * data remains untouched, and it's up to the caller to free the
832 * memory space indicated by @new_mem.
833 * Returns:
834 * !0: Failure.
835 */
836
837int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
838 struct ttm_operation_ctx *ctx,
839 struct ttm_mem_reg *new_mem);
840
841/**
842 * ttm_bo_free_old_node
843 *
844 * @bo: A pointer to a struct ttm_buffer_object.
845 *
846 * Utility function to free an old placement after a successful move.
847 */
848void ttm_bo_free_old_node(struct ttm_buffer_object *bo);
849
850/**
851 * ttm_bo_move_accel_cleanup.
852 *
853 * @bo: A pointer to a struct ttm_buffer_object.
854 * @fence: A fence object that signals when moving is complete.
855 * @evict: This is an evict move. Don't return until the buffer is idle.
856 * @new_mem: struct ttm_mem_reg indicating where to move.
857 *
858 * Accelerated move function to be called when an accelerated move
859 * has been scheduled. The function will create a new temporary buffer object
860 * representing the old placement, and put the sync object on both buffer
861 * objects. After that the newly created buffer object is unref'd to be
862 * destroyed when the move is complete. This will help pipeline
863 * buffer moves.
864 */
865int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
866 struct dma_fence *fence, bool evict,
867 struct ttm_mem_reg *new_mem);
868
869/**
870 * ttm_bo_pipeline_move.
871 *
872 * @bo: A pointer to a struct ttm_buffer_object.
873 * @fence: A fence object that signals when moving is complete.
874 * @evict: This is an evict move. Don't return until the buffer is idle.
875 * @new_mem: struct ttm_mem_reg indicating where to move.
876 *
877 * Function for pipelining accelerated moves. Either free the memory
878 * immediately or hang it on a temporary buffer object.
879 */
880int ttm_bo_pipeline_move(struct ttm_buffer_object *bo,
881 struct dma_fence *fence, bool evict,
882 struct ttm_mem_reg *new_mem);
883
884/**
885 * ttm_bo_pipeline_gutting.
886 *
887 * @bo: A pointer to a struct ttm_buffer_object.
888 *
889 * Pipelined gutting a BO of its backing store.
890 */
891int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo);
892
893/**
894 * ttm_io_prot
895 *
896 * @c_state: Caching state.
897 * @tmp: Page protection flag for a normal, cached mapping.
898 *
899 * Utility function that returns the pgprot_t that should be used for
900 * setting up a PTE with the caching model indicated by @c_state.
901 */
902pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp);
903
904extern const struct ttm_mem_type_manager_func ttm_bo_manager_func;
905
906#endif