ttm_bo.h

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 27/*
 28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 29 */
 30
 31#ifndef _TTM_BO_API_H_
 32#define _TTM_BO_API_H_
 33
 34#include <drm/drm_gem.h>
 35
 36#include <linux/kref.h>
 37#include <linux/list.h>
 38
 39#include "ttm_device.h"
 40
 41/* Default number of pre-faulted pages in the TTM fault handler */
 42#define TTM_BO_VM_NUM_PREFAULT 16
 43
 44struct iosys_map;
 45
 46struct ttm_global;
 47struct ttm_device;
 48struct ttm_placement;
 49struct ttm_place;
 50struct ttm_resource;
 51struct ttm_resource_manager;
 52struct ttm_tt;
 53
 54/**
 55 * enum ttm_bo_type
 56 *
 57 * @ttm_bo_type_device:	These are 'normal' buffers that can
 58 * be mmapped by user space. Each of these bos occupy a slot in the
 59 * device address space, that can be used for normal vm operations.
 60 *
 61 * @ttm_bo_type_kernel: These buffers are like ttm_bo_type_device buffers,
 62 * but they cannot be accessed from user-space. For kernel-only use.
 63 *
 64 * @ttm_bo_type_sg: Buffer made from dmabuf sg table shared with another
 65 * driver.
 66 */
 67enum ttm_bo_type {
 68	ttm_bo_type_device,
 69	ttm_bo_type_kernel,
 70	ttm_bo_type_sg
 71};
 72
 73/**
 74 * struct ttm_buffer_object
 75 *
 76 * @base: drm_gem_object superclass data.
 77 * @bdev: Pointer to the buffer object device structure.
 78 * @type: The bo type.
 79 * @page_alignment: Page alignment.
 80 * @destroy: Destruction function. If NULL, kfree is used.
 81 * @kref: Reference count of this buffer object. When this refcount reaches
 82 * zero, the object is destroyed or put on the delayed delete list.
 83 * @resource: structure describing current placement.
 84 * @ttm: TTM structure holding system pages.
 85 * @deleted: True if the object is only a zombie and already deleted.
 86 * @bulk_move: The bulk move object.
 87 * @priority: Priority for LRU, BOs with lower priority are evicted first.
 88 * @pin_count: Pin count.
 89 *
 90 * Base class for TTM buffer object, that deals with data placement and CPU
 91 * mappings. GPU mappings are really up to the driver, but for simpler GPUs
 92 * the driver can usually use the placement offset @offset directly as the
 93 * GPU virtual address. For drivers implementing multiple
 94 * GPU memory manager contexts, the driver should manage the address space
 95 * in these contexts separately and use these objects to get the correct
 96 * placement and caching for these GPU maps. This makes it possible to use
 97 * these objects for even quite elaborate memory management schemes.
 98 * The destroy member, the API visibility of this object makes it possible
 99 * to derive driver specific types.
100 */
101struct ttm_buffer_object {
102	struct drm_gem_object base;
103
104	/*
105	 * Members constant at init.
106	 */
107	struct ttm_device *bdev;
108	enum ttm_bo_type type;
109	uint32_t page_alignment;
110	void (*destroy) (struct ttm_buffer_object *);
111
112	/*
113	* Members not needing protection.
114	*/
115	struct kref kref;
116
117	/*
118	 * Members protected by the bo::resv::reserved lock.
119	 */
120	struct ttm_resource *resource;
121	struct ttm_tt *ttm;
122	bool deleted;
123	struct ttm_lru_bulk_move *bulk_move;
124	unsigned priority;
125	unsigned pin_count;
126
127	/**
128	 * @delayed_delete: Work item used when we can't delete the BO
129	 * immediately
130	 */
131	struct work_struct delayed_delete;
132
133	/**
134	 * @sg: external source of pages and DMA addresses, protected by the
135	 * reservation lock.
136	 */
137	struct sg_table *sg;
138};
139
140#define TTM_BO_MAP_IOMEM_MASK 0x80
141
142/**
143 * struct ttm_bo_kmap_obj
144 *
145 * @virtual: The current kernel virtual address.
146 * @page: The page when kmap'ing a single page.
147 * @bo_kmap_type: Type of bo_kmap.
148 * @bo: The TTM BO.
149 *
150 * Object describing a kernel mapping. Since a TTM bo may be located
151 * in various memory types with various caching policies, the
152 * mapping can either be an ioremap, a vmap, a kmap or part of a
153 * premapped region.
154 */
155struct ttm_bo_kmap_obj {
156	void *virtual;
157	struct page *page;
158	enum {
159		ttm_bo_map_iomap        = 1 | TTM_BO_MAP_IOMEM_MASK,
160		ttm_bo_map_vmap         = 2,
161		ttm_bo_map_kmap         = 3,
162		ttm_bo_map_premapped    = 4 | TTM_BO_MAP_IOMEM_MASK,
163	} bo_kmap_type;
164	struct ttm_buffer_object *bo;
165};
166
167/**
168 * struct ttm_operation_ctx
169 *
170 * @interruptible: Sleep interruptible if sleeping.
171 * @no_wait_gpu: Return immediately if the GPU is busy.
172 * @gfp_retry_mayfail: Set the __GFP_RETRY_MAYFAIL when allocation pages.
173 * @allow_res_evict: Allow eviction of reserved BOs. Can be used when multiple
174 * BOs share the same reservation object.
175 * faults. Should only be used by TTM internally.
176 * @resv: Reservation object to allow reserved evictions with.
177 * @bytes_moved: Statistics on how many bytes have been moved.
178 *
179 * Context for TTM operations like changing buffer placement or general memory
180 * allocation.
181 */
182struct ttm_operation_ctx {
183	bool interruptible;
184	bool no_wait_gpu;
185	bool gfp_retry_mayfail;
186	bool allow_res_evict;
187	struct dma_resv *resv;
188	uint64_t bytes_moved;
189};
190
191struct ttm_lru_walk;
192
193/** struct ttm_lru_walk_ops - Operations for a LRU walk. */
194struct ttm_lru_walk_ops {
195	/**
196	 * process_bo - Process this bo.
197	 * @walk: struct ttm_lru_walk describing the walk.
198	 * @bo: A locked and referenced buffer object.
199	 *
200	 * Return: Negative error code on error, User-defined positive value
201	 * (typically, but not always, size of the processed bo) on success.
202	 * On success, the returned values are summed by the walk and the
203	 * walk exits when its target is met.
204	 * 0 also indicates success, -EBUSY means this bo was skipped.
205	 */
206	s64 (*process_bo)(struct ttm_lru_walk *walk, struct ttm_buffer_object *bo);
207};
208
209/**
210 * struct ttm_lru_walk_arg - Common part for the variants of BO LRU walk.
211 */
212struct ttm_lru_walk_arg {
213	/** @ctx: Pointer to the struct ttm_operation_ctx. */
214	struct ttm_operation_ctx *ctx;
215	/** @ticket: The struct ww_acquire_ctx if any. */
216	struct ww_acquire_ctx *ticket;
217	/** @trylock_only: Only use trylock for locking. */
218	bool trylock_only;
219};
220
221/**
222 * struct ttm_lru_walk - Structure describing a LRU walk.
223 */
224struct ttm_lru_walk {
225	/** @ops: Pointer to the ops structure. */
226	const struct ttm_lru_walk_ops *ops;
227	/** @arg: Common bo LRU walk arguments. */
228	struct ttm_lru_walk_arg arg;
229};
230
231s64 ttm_lru_walk_for_evict(struct ttm_lru_walk *walk, struct ttm_device *bdev,
232			   struct ttm_resource_manager *man, s64 target);
233
234/**
235 * struct ttm_bo_shrink_flags - flags to govern the bo shrinking behaviour
236 * @purge: Purge the content rather than backing it up.
237 * @writeback: Attempt to immediately write content to swap space.
238 * @allow_move: Allow moving to system before shrinking. This is typically
239 * not desired for zombie- or ghost objects (with zombie object meaning
240 * objects with a zero gem object refcount)
241 */
242struct ttm_bo_shrink_flags {
243	u32 purge : 1;
244	u32 writeback : 1;
245	u32 allow_move : 1;
246};
247
248long ttm_bo_shrink(struct ttm_operation_ctx *ctx, struct ttm_buffer_object *bo,
249		   const struct ttm_bo_shrink_flags flags);
250
251bool ttm_bo_shrink_suitable(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx);
252
253bool ttm_bo_shrink_avoid_wait(void);
254
255/**
256 * ttm_bo_reserve:
257 *
258 * @bo: A pointer to a struct ttm_buffer_object.
259 * @interruptible: Sleep interruptible if waiting.
260 * @no_wait: Don't sleep while trying to reserve, rather return -EBUSY.
261 * @ticket: ticket used to acquire the ww_mutex.
262 *
263 * Locks a buffer object for validation. (Or prevents other processes from
264 * locking it for validation), while taking a number of measures to prevent
265 * deadlocks.
266 *
267 * Returns:
268 * -EDEADLK: The reservation may cause a deadlock.
269 * Release all buffer reservations, wait for @bo to become unreserved and
270 * try again.
271 * -ERESTARTSYS: A wait for the buffer to become unreserved was interrupted by
272 * a signal. Release all buffer reservations and return to user-space.
273 * -EBUSY: The function needed to sleep, but @no_wait was true
274 * -EALREADY: Bo already reserved using @ticket. This error code will only
275 * be returned if @use_ticket is set to true.
276 */
277static inline int ttm_bo_reserve(struct ttm_buffer_object *bo,
278				 bool interruptible, bool no_wait,
279				 struct ww_acquire_ctx *ticket)
280{
281	int ret = 0;
282
283	if (no_wait) {
284		bool success;
285
286		if (WARN_ON(ticket))
287			return -EBUSY;
288
289		success = dma_resv_trylock(bo->base.resv);
290		return success ? 0 : -EBUSY;
291	}
292
293	if (interruptible)
294		ret = dma_resv_lock_interruptible(bo->base.resv, ticket);
295	else
296		ret = dma_resv_lock(bo->base.resv, ticket);
297	if (ret == -EINTR)
298		return -ERESTARTSYS;
299	return ret;
300}
301
302/**
303 * ttm_bo_reserve_slowpath:
304 * @bo: A pointer to a struct ttm_buffer_object.
305 * @interruptible: Sleep interruptible if waiting.
306 * @ticket: Ticket used to acquire the ww_mutex.
307 *
308 * This is called after ttm_bo_reserve returns -EAGAIN and we backed off
309 * from all our other reservations. Because there are no other reservations
310 * held by us, this function cannot deadlock any more.
311 */
312static inline int ttm_bo_reserve_slowpath(struct ttm_buffer_object *bo,
313					  bool interruptible,
314					  struct ww_acquire_ctx *ticket)
315{
316	if (interruptible) {
317		int ret = dma_resv_lock_slow_interruptible(bo->base.resv,
318							   ticket);
319		if (ret == -EINTR)
320			ret = -ERESTARTSYS;
321		return ret;
322	}
323	dma_resv_lock_slow(bo->base.resv, ticket);
324	return 0;
325}
326
327void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo);
328
329static inline void
330ttm_bo_move_to_lru_tail_unlocked(struct ttm_buffer_object *bo)
331{
332	spin_lock(&bo->bdev->lru_lock);
333	ttm_bo_move_to_lru_tail(bo);
334	spin_unlock(&bo->bdev->lru_lock);
335}
336
337static inline void ttm_bo_assign_mem(struct ttm_buffer_object *bo,
338				     struct ttm_resource *new_mem)
339{
340	WARN_ON(bo->resource);
341	bo->resource = new_mem;
342}
343
344/**
345 * ttm_bo_move_null - assign memory for a buffer object.
346 * @bo: The bo to assign the memory to
347 * @new_mem: The memory to be assigned.
348 *
349 * Assign the memory from new_mem to the memory of the buffer object bo.
350 */
351static inline void ttm_bo_move_null(struct ttm_buffer_object *bo,
352				    struct ttm_resource *new_mem)
353{
354	ttm_resource_free(bo, &bo->resource);
355	ttm_bo_assign_mem(bo, new_mem);
356}
357
358/**
359 * ttm_bo_unreserve
360 *
361 * @bo: A pointer to a struct ttm_buffer_object.
362 *
363 * Unreserve a previous reservation of @bo.
364 */
365static inline void ttm_bo_unreserve(struct ttm_buffer_object *bo)
366{
367	ttm_bo_move_to_lru_tail_unlocked(bo);
368	dma_resv_unlock(bo->base.resv);
369}
370
371/**
372 * ttm_kmap_obj_virtual
373 *
374 * @map: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap.
375 * @is_iomem: Pointer to an integer that on return indicates 1 if the
376 * virtual map is io memory, 0 if normal memory.
377 *
378 * Returns the virtual address of a buffer object area mapped by ttm_bo_kmap.
379 * If *is_iomem is 1 on return, the virtual address points to an io memory area,
380 * that should strictly be accessed by the iowriteXX() and similar functions.
381 */
382static inline void *ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj *map,
383					 bool *is_iomem)
384{
385	*is_iomem = !!(map->bo_kmap_type & TTM_BO_MAP_IOMEM_MASK);
386	return map->virtual;
387}
388
389int ttm_bo_wait_ctx(struct ttm_buffer_object *bo,
390		    struct ttm_operation_ctx *ctx);
391int ttm_bo_validate(struct ttm_buffer_object *bo,
392		    struct ttm_placement *placement,
393		    struct ttm_operation_ctx *ctx);
394void ttm_bo_fini(struct ttm_buffer_object *bo);
395void ttm_bo_set_bulk_move(struct ttm_buffer_object *bo,
396			  struct ttm_lru_bulk_move *bulk);
397bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
398			      const struct ttm_place *place);
399int ttm_bo_init_reserved(struct ttm_device *bdev, struct ttm_buffer_object *bo,
400			 enum ttm_bo_type type, struct ttm_placement *placement,
401			 uint32_t alignment, struct ttm_operation_ctx *ctx,
402			 struct sg_table *sg, struct dma_resv *resv,
403			 void (*destroy)(struct ttm_buffer_object *));
404int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo,
405			 enum ttm_bo_type type, struct ttm_placement *placement,
406			 uint32_t alignment, bool interruptible,
407			 struct sg_table *sg, struct dma_resv *resv,
408			 void (*destroy)(struct ttm_buffer_object *));
409int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
410		unsigned long num_pages, struct ttm_bo_kmap_obj *map);
411void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
412void *ttm_bo_kmap_try_from_panic(struct ttm_buffer_object *bo, unsigned long page);
413int ttm_bo_vmap(struct ttm_buffer_object *bo, struct iosys_map *map);
414void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct iosys_map *map);
415int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo);
416s64 ttm_bo_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
417		   struct ttm_resource_manager *man, gfp_t gfp_flags,
418		   s64 target);
419void ttm_bo_pin(struct ttm_buffer_object *bo);
420void ttm_bo_unpin(struct ttm_buffer_object *bo);
421int ttm_bo_evict_first(struct ttm_device *bdev,
422		       struct ttm_resource_manager *man,
423		       struct ttm_operation_ctx *ctx);
424int ttm_bo_access(struct ttm_buffer_object *bo, unsigned long offset,
425		  void *buf, int len, int write);
426vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo,
427			     struct vm_fault *vmf);
428vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
429				    pgprot_t prot,
430				    pgoff_t num_prefault);
431vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf);
432void ttm_bo_vm_open(struct vm_area_struct *vma);
433void ttm_bo_vm_close(struct vm_area_struct *vma);
434int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
435		     void *buf, int len, int write);
436vm_fault_t ttm_bo_vm_dummy_page(struct vm_fault *vmf, pgprot_t prot);
437
438int ttm_bo_mem_space(struct ttm_buffer_object *bo,
439		     struct ttm_placement *placement,
440		     struct ttm_resource **mem,
441		     struct ttm_operation_ctx *ctx);
442
443void ttm_bo_unmap_virtual(struct ttm_buffer_object *bo);
444/*
445 * ttm_bo_util.c
446 */
447int ttm_mem_io_reserve(struct ttm_device *bdev,
448		       struct ttm_resource *mem);
449void ttm_mem_io_free(struct ttm_device *bdev,
450		     struct ttm_resource *mem);
451void ttm_move_memcpy(bool clear, u32 num_pages,
452		     struct ttm_kmap_iter *dst_iter,
453		     struct ttm_kmap_iter *src_iter);
454int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
455		       struct ttm_operation_ctx *ctx,
456		       struct ttm_resource *new_mem);
457int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
458			      struct dma_fence *fence, bool evict,
459			      bool pipeline,
460			      struct ttm_resource *new_mem);
461void ttm_bo_move_sync_cleanup(struct ttm_buffer_object *bo,
462			      struct ttm_resource *new_mem);
463int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo);
464pgprot_t ttm_io_prot(struct ttm_buffer_object *bo, struct ttm_resource *res,
465		     pgprot_t tmp);
466void ttm_bo_tt_destroy(struct ttm_buffer_object *bo);
467int ttm_bo_populate(struct ttm_buffer_object *bo,
468		    struct ttm_operation_ctx *ctx);
469int ttm_bo_setup_export(struct ttm_buffer_object *bo,
470			struct ttm_operation_ctx *ctx);
471
472/* Driver LRU walk helpers initially targeted for shrinking. */
473
474/**
475 * struct ttm_bo_lru_cursor - Iterator cursor for TTM LRU list looping
476 */
477struct ttm_bo_lru_cursor {
478	/** @res_curs: Embedded struct ttm_resource_cursor. */
479	struct ttm_resource_cursor res_curs;
480	/**
481	 * @bo: Buffer object pointer if a buffer object is refcounted,
482	 * NULL otherwise.
483	 */
484	struct ttm_buffer_object *bo;
485	/**
486	 * @needs_unlock: Valid iff @bo != NULL. The bo resv needs
487	 * unlock before the next iteration or after loop exit.
488	 */
489	bool needs_unlock;
490	/** @arg: Pointer to common BO LRU walk arguments. */
491	struct ttm_lru_walk_arg *arg;
492};
493
494void ttm_bo_lru_cursor_fini(struct ttm_bo_lru_cursor *curs);
495
496struct ttm_bo_lru_cursor *
497ttm_bo_lru_cursor_init(struct ttm_bo_lru_cursor *curs,
498		       struct ttm_resource_manager *man,
499		       struct ttm_lru_walk_arg *arg);
500
501struct ttm_buffer_object *ttm_bo_lru_cursor_first(struct ttm_bo_lru_cursor *curs);
502
503struct ttm_buffer_object *ttm_bo_lru_cursor_next(struct ttm_bo_lru_cursor *curs);
504
505/*
506 * Defines needed to use autocleanup (linux/cleanup.h) with struct ttm_bo_lru_cursor.
507 */
508DEFINE_CLASS(ttm_bo_lru_cursor, struct ttm_bo_lru_cursor *,
509	     if (_T) {ttm_bo_lru_cursor_fini(_T); },
510	     ttm_bo_lru_cursor_init(curs, man, arg),
511	     struct ttm_bo_lru_cursor *curs, struct ttm_resource_manager *man,
512	     struct ttm_lru_walk_arg *arg);
513static inline void *
514class_ttm_bo_lru_cursor_lock_ptr(class_ttm_bo_lru_cursor_t *_T)
515{ return *_T; }
516#define class_ttm_bo_lru_cursor_is_conditional false
517
518/**
519 * ttm_bo_lru_for_each_reserved_guarded() - Iterate over buffer objects owning
520 * resources on LRU lists.
521 * @_cursor: struct ttm_bo_lru_cursor to use for the iteration.
522 * @_man: The resource manager whose LRU lists to iterate over.
523 * @_arg: The struct ttm_lru_walk_arg to govern the LRU walk.
524 * @_bo: The struct ttm_buffer_object pointer pointing to the buffer object
525 * for the current iteration.
526 *
527 * Iterate over all resources of @_man and for each resource, attempt to
528 * reference and lock (using the locking mode detailed in @_ctx) the buffer
529 * object it points to. If successful, assign @_bo to the address of the
530 * buffer object and update @_cursor. The iteration is guarded in the
531 * sense that @_cursor will be initialized before looping start and cleaned
532 * up at looping termination, even if terminated prematurely by, for
533 * example a return or break statement. Exiting the loop will also unlock
534 * (if needed) and unreference @_bo.
535 *
536 * Return: If locking of a bo returns an error, then iteration is terminated
537 * and @_bo is set to a corresponding error pointer. It's illegal to
538 * dereference @_bo after loop exit.
539 */
540#define ttm_bo_lru_for_each_reserved_guarded(_cursor, _man, _arg, _bo)	\
541	scoped_guard(ttm_bo_lru_cursor, _cursor, _man, _arg)		\
542		for ((_bo) = ttm_bo_lru_cursor_first(_cursor);		\
543		       !IS_ERR_OR_NULL(_bo);				\
544		       (_bo) = ttm_bo_lru_cursor_next(_cursor))
545
546#endif