xref: /openbsd/sys/dev/pci/drm/amd/amdgpu/amdgpu_vm.h (revision f005ef32)
1 /*
2  * Copyright 2016 Advanced Micro Devices, Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  *
22  * Authors: Christian König
23  */
24 #ifndef __AMDGPU_VM_H__
25 #define __AMDGPU_VM_H__
26 
27 #include <linux/idr.h>
28 #include <linux/kfifo.h>
29 #include <linux/rbtree.h>
30 #include <drm/gpu_scheduler.h>
31 #include <drm/drm_file.h>
32 #include <drm/ttm/ttm_bo.h>
33 #include <linux/sched/mm.h>
34 
35 #include "amdgpu_sync.h"
36 #include "amdgpu_ring.h"
37 #include "amdgpu_ids.h"
38 
39 struct drm_exec;
40 
41 struct amdgpu_bo_va;
42 struct amdgpu_job;
43 struct amdgpu_bo_list_entry;
44 struct amdgpu_bo_vm;
45 struct amdgpu_mem_stats;
46 
47 /*
48  * GPUVM handling
49  */
50 
51 /* Maximum number of PTEs the hardware can write with one command */
52 #define AMDGPU_VM_MAX_UPDATE_SIZE	0x3FFFF
53 
54 /* number of entries in page table */
55 #define AMDGPU_VM_PTE_COUNT(adev) (1 << (adev)->vm_manager.block_size)
56 
57 #define AMDGPU_PTE_VALID	(1ULL << 0)
58 #define AMDGPU_PTE_SYSTEM	(1ULL << 1)
59 #define AMDGPU_PTE_SNOOPED	(1ULL << 2)
60 
61 /* RV+ */
62 #define AMDGPU_PTE_TMZ		(1ULL << 3)
63 
64 /* VI only */
65 #define AMDGPU_PTE_EXECUTABLE	(1ULL << 4)
66 
67 #define AMDGPU_PTE_READABLE	(1ULL << 5)
68 #define AMDGPU_PTE_WRITEABLE	(1ULL << 6)
69 
70 #define AMDGPU_PTE_FRAG(x)	((x & 0x1fULL) << 7)
71 
72 /* TILED for VEGA10, reserved for older ASICs  */
73 #define AMDGPU_PTE_PRT		(1ULL << 51)
74 
75 /* PDE is handled as PTE for VEGA10 */
76 #define AMDGPU_PDE_PTE		(1ULL << 54)
77 
78 #define AMDGPU_PTE_LOG          (1ULL << 55)
79 
80 /* PTE is handled as PDE for VEGA10 (Translate Further) */
81 #define AMDGPU_PTE_TF		(1ULL << 56)
82 
83 /* MALL noalloc for sienna_cichlid, reserved for older ASICs  */
84 #define AMDGPU_PTE_NOALLOC	(1ULL << 58)
85 
86 /* PDE Block Fragment Size for VEGA10 */
87 #define AMDGPU_PDE_BFS(a)	((uint64_t)a << 59)
88 
89 /* Flag combination to set no-retry with TF disabled */
90 #define AMDGPU_VM_NORETRY_FLAGS	(AMDGPU_PTE_EXECUTABLE | AMDGPU_PDE_PTE | \
91 				AMDGPU_PTE_TF)
92 
93 /* Flag combination to set no-retry with TF enabled */
94 #define AMDGPU_VM_NORETRY_FLAGS_TF (AMDGPU_PTE_VALID | AMDGPU_PTE_SYSTEM | \
95 				   AMDGPU_PTE_PRT)
96 /* For GFX9 */
97 #define AMDGPU_PTE_MTYPE_VG10(a)	((uint64_t)(a) << 57)
98 #define AMDGPU_PTE_MTYPE_VG10_MASK	AMDGPU_PTE_MTYPE_VG10(3ULL)
99 
100 #define AMDGPU_MTYPE_NC 0
101 #define AMDGPU_MTYPE_CC 2
102 
103 #define AMDGPU_PTE_DEFAULT_ATC  (AMDGPU_PTE_SYSTEM      \
104                                 | AMDGPU_PTE_SNOOPED    \
105                                 | AMDGPU_PTE_EXECUTABLE \
106                                 | AMDGPU_PTE_READABLE   \
107                                 | AMDGPU_PTE_WRITEABLE  \
108                                 | AMDGPU_PTE_MTYPE_VG10(AMDGPU_MTYPE_CC))
109 
110 /* gfx10 */
111 #define AMDGPU_PTE_MTYPE_NV10(a)       ((uint64_t)(a) << 48)
112 #define AMDGPU_PTE_MTYPE_NV10_MASK     AMDGPU_PTE_MTYPE_NV10(7ULL)
113 
114 /* How to program VM fault handling */
115 #define AMDGPU_VM_FAULT_STOP_NEVER	0
116 #define AMDGPU_VM_FAULT_STOP_FIRST	1
117 #define AMDGPU_VM_FAULT_STOP_ALWAYS	2
118 
119 /* Reserve 4MB VRAM for page tables */
120 #define AMDGPU_VM_RESERVED_VRAM		(8ULL << 20)
121 
122 /*
123  * max number of VMHUB
124  * layout: max 8 GFXHUB + 4 MMHUB0 + 1 MMHUB1
125  */
126 #define AMDGPU_MAX_VMHUBS			13
127 #define AMDGPU_GFXHUB(x)			(x)
128 #define AMDGPU_MMHUB0(x)			(8 + x)
129 #define AMDGPU_MMHUB1(x)			(8 + 4 + x)
130 
131 /* Reserve 2MB at top/bottom of address space for kernel use */
132 #define AMDGPU_VA_RESERVED_SIZE			(2ULL << 20)
133 
134 /* See vm_update_mode */
135 #define AMDGPU_VM_USE_CPU_FOR_GFX (1 << 0)
136 #define AMDGPU_VM_USE_CPU_FOR_COMPUTE (1 << 1)
137 
138 /* VMPT level enumerate, and the hiberachy is:
139  * PDB2->PDB1->PDB0->PTB
140  */
141 enum amdgpu_vm_level {
142 	AMDGPU_VM_PDB2,
143 	AMDGPU_VM_PDB1,
144 	AMDGPU_VM_PDB0,
145 	AMDGPU_VM_PTB
146 };
147 
148 /* base structure for tracking BO usage in a VM */
149 struct amdgpu_vm_bo_base {
150 	/* constant after initialization */
151 	struct amdgpu_vm		*vm;
152 	struct amdgpu_bo		*bo;
153 
154 	/* protected by bo being reserved */
155 	struct amdgpu_vm_bo_base	*next;
156 
157 	/* protected by spinlock */
158 	struct list_head		vm_status;
159 
160 	/* protected by the BO being reserved */
161 	bool				moved;
162 };
163 
164 /* provided by hw blocks that can write ptes, e.g., sdma */
165 struct amdgpu_vm_pte_funcs {
166 	/* number of dw to reserve per operation */
167 	unsigned	copy_pte_num_dw;
168 
169 	/* copy pte entries from GART */
170 	void (*copy_pte)(struct amdgpu_ib *ib,
171 			 uint64_t pe, uint64_t src,
172 			 unsigned count);
173 
174 	/* write pte one entry at a time with addr mapping */
175 	void (*write_pte)(struct amdgpu_ib *ib, uint64_t pe,
176 			  uint64_t value, unsigned count,
177 			  uint32_t incr);
178 	/* for linear pte/pde updates without addr mapping */
179 	void (*set_pte_pde)(struct amdgpu_ib *ib,
180 			    uint64_t pe,
181 			    uint64_t addr, unsigned count,
182 			    uint32_t incr, uint64_t flags);
183 };
184 
185 struct amdgpu_task_info {
186 	char	process_name[TASK_COMM_LEN];
187 	char	task_name[TASK_COMM_LEN];
188 	pid_t	pid;
189 	pid_t	tgid;
190 };
191 
192 /**
193  * struct amdgpu_vm_update_params
194  *
195  * Encapsulate some VM table update parameters to reduce
196  * the number of function parameters
197  *
198  */
199 struct amdgpu_vm_update_params {
200 
201 	/**
202 	 * @adev: amdgpu device we do this update for
203 	 */
204 	struct amdgpu_device *adev;
205 
206 	/**
207 	 * @vm: optional amdgpu_vm we do this update for
208 	 */
209 	struct amdgpu_vm *vm;
210 
211 	/**
212 	 * @immediate: if changes should be made immediately
213 	 */
214 	bool immediate;
215 
216 	/**
217 	 * @unlocked: true if the root BO is not locked
218 	 */
219 	bool unlocked;
220 
221 	/**
222 	 * @pages_addr:
223 	 *
224 	 * DMA addresses to use for mapping
225 	 */
226 	dma_addr_t *pages_addr;
227 
228 	/**
229 	 * @job: job to used for hw submission
230 	 */
231 	struct amdgpu_job *job;
232 
233 	/**
234 	 * @num_dw_left: number of dw left for the IB
235 	 */
236 	unsigned int num_dw_left;
237 
238 	/**
239 	 * @table_freed: return true if page table is freed when updating
240 	 */
241 	bool table_freed;
242 };
243 
244 struct amdgpu_vm_update_funcs {
245 	int (*map_table)(struct amdgpu_bo_vm *bo);
246 	int (*prepare)(struct amdgpu_vm_update_params *p, struct dma_resv *resv,
247 		       enum amdgpu_sync_mode sync_mode);
248 	int (*update)(struct amdgpu_vm_update_params *p,
249 		      struct amdgpu_bo_vm *bo, uint64_t pe, uint64_t addr,
250 		      unsigned count, uint32_t incr, uint64_t flags);
251 	int (*commit)(struct amdgpu_vm_update_params *p,
252 		      struct dma_fence **fence);
253 };
254 
255 struct amdgpu_vm_fault {
256 	SIMPLEQ_ENTRY(amdgpu_vm_fault)	vm_fault_entry;
257 	uint64_t			val;
258 };
259 SIMPLEQ_HEAD(amdgpu_vm_faults, amdgpu_vm_fault);
260 
261 struct amdgpu_vm {
262 	/* tree of virtual addresses mapped */
263 	struct rb_root_cached	va;
264 
265 	/* Lock to prevent eviction while we are updating page tables
266 	 * use vm_eviction_lock/unlock(vm)
267 	 */
268 	struct rwlock		eviction_lock;
269 	bool			evicting;
270 	unsigned int		saved_flags;
271 
272 	/* Lock to protect vm_bo add/del/move on all lists of vm */
273 	spinlock_t		status_lock;
274 
275 	/* BOs who needs a validation */
276 	struct list_head	evicted;
277 
278 	/* PT BOs which relocated and their parent need an update */
279 	struct list_head	relocated;
280 
281 	/* per VM BOs moved, but not yet updated in the PT */
282 	struct list_head	moved;
283 
284 	/* All BOs of this VM not currently in the state machine */
285 	struct list_head	idle;
286 
287 	/* regular invalidated BOs, but not yet updated in the PT */
288 	struct list_head	invalidated;
289 
290 	/* BO mappings freed, but not yet updated in the PT */
291 	struct list_head	freed;
292 
293 	/* BOs which are invalidated, has been updated in the PTs */
294 	struct list_head        done;
295 
296 	/* PT BOs scheduled to free and fill with zero if vm_resv is not hold */
297 	struct list_head	pt_freed;
298 	struct work_struct	pt_free_work;
299 
300 	/* contains the page directory */
301 	struct amdgpu_vm_bo_base     root;
302 	struct dma_fence	*last_update;
303 
304 	/* Scheduler entities for page table updates */
305 	struct drm_sched_entity	immediate;
306 	struct drm_sched_entity	delayed;
307 
308 	/* Last finished delayed update */
309 	atomic64_t		tlb_seq;
310 	struct dma_fence	*last_tlb_flush;
311 
312 	/* How many times we had to re-generate the page tables */
313 	uint64_t		generation;
314 
315 	/* Last unlocked submission to the scheduler entities */
316 	struct dma_fence	*last_unlocked;
317 
318 	unsigned int		pasid;
319 	bool			reserved_vmid[AMDGPU_MAX_VMHUBS];
320 
321 	/* Flag to indicate if VM tables are updated by CPU or GPU (SDMA) */
322 	bool					use_cpu_for_update;
323 
324 	/* Functions to use for VM table updates */
325 	const struct amdgpu_vm_update_funcs	*update_funcs;
326 
327 	/* Flag to indicate ATS support from PTE for GFX9 */
328 	bool			pte_support_ats;
329 
330 #ifdef __linux__
331 	/* Up to 128 pending retry page faults */
332 	DECLARE_KFIFO(faults, u64, 128);
333 #else
334 	struct amdgpu_vm_faults faults;
335 #endif
336 
337 	/* Points to the KFD process VM info */
338 	struct amdkfd_process_info *process_info;
339 
340 	/* List node in amdkfd_process_info.vm_list_head */
341 	struct list_head	vm_list_node;
342 
343 	/* Valid while the PD is reserved or fenced */
344 	uint64_t		pd_phys_addr;
345 
346 	/* Some basic info about the task */
347 	struct amdgpu_task_info task_info;
348 
349 	/* Store positions of group of BOs */
350 	struct ttm_lru_bulk_move lru_bulk_move;
351 	/* Flag to indicate if VM is used for compute */
352 	bool			is_compute_context;
353 
354 	/* Memory partition number, -1 means any partition */
355 	int8_t			mem_id;
356 };
357 
358 struct amdgpu_vm_manager {
359 	/* Handling of VMIDs */
360 	struct amdgpu_vmid_mgr			id_mgr[AMDGPU_MAX_VMHUBS];
361 	unsigned int				first_kfd_vmid;
362 	bool					concurrent_flush;
363 
364 	/* Handling of VM fences */
365 	u64					fence_context;
366 	unsigned				seqno[AMDGPU_MAX_RINGS];
367 
368 	uint64_t				max_pfn;
369 	uint32_t				num_level;
370 	uint32_t				block_size;
371 	uint32_t				fragment_size;
372 	enum amdgpu_vm_level			root_level;
373 	/* vram base address for page table entry  */
374 	u64					vram_base_offset;
375 	/* vm pte handling */
376 	const struct amdgpu_vm_pte_funcs	*vm_pte_funcs;
377 	struct drm_gpu_scheduler		*vm_pte_scheds[AMDGPU_MAX_RINGS];
378 	unsigned				vm_pte_num_scheds;
379 	struct amdgpu_ring			*page_fault;
380 
381 	/* partial resident texture handling */
382 	spinlock_t				prt_lock;
383 	atomic_t				num_prt_users;
384 
385 	/* controls how VM page tables are updated for Graphics and Compute.
386 	 * BIT0[= 0] Graphics updated by SDMA [= 1] by CPU
387 	 * BIT1[= 0] Compute updated by SDMA [= 1] by CPU
388 	 */
389 	int					vm_update_mode;
390 
391 	/* PASID to VM mapping, will be used in interrupt context to
392 	 * look up VM of a page fault
393 	 */
394 	struct xarray				pasids;
395 };
396 
397 struct amdgpu_bo_va_mapping;
398 
399 #define amdgpu_vm_copy_pte(adev, ib, pe, src, count) ((adev)->vm_manager.vm_pte_funcs->copy_pte((ib), (pe), (src), (count)))
400 #define amdgpu_vm_write_pte(adev, ib, pe, value, count, incr) ((adev)->vm_manager.vm_pte_funcs->write_pte((ib), (pe), (value), (count), (incr)))
401 #define amdgpu_vm_set_pte_pde(adev, ib, pe, addr, count, incr, flags) ((adev)->vm_manager.vm_pte_funcs->set_pte_pde((ib), (pe), (addr), (count), (incr), (flags)))
402 
403 extern const struct amdgpu_vm_update_funcs amdgpu_vm_cpu_funcs;
404 extern const struct amdgpu_vm_update_funcs amdgpu_vm_sdma_funcs;
405 
406 void amdgpu_vm_manager_init(struct amdgpu_device *adev);
407 void amdgpu_vm_manager_fini(struct amdgpu_device *adev);
408 
409 int amdgpu_vm_set_pasid(struct amdgpu_device *adev, struct amdgpu_vm *vm,
410 			u32 pasid);
411 
412 long amdgpu_vm_wait_idle(struct amdgpu_vm *vm, long timeout);
413 int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm, int32_t xcp_id);
414 int amdgpu_vm_make_compute(struct amdgpu_device *adev, struct amdgpu_vm *vm);
415 void amdgpu_vm_release_compute(struct amdgpu_device *adev, struct amdgpu_vm *vm);
416 void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm);
417 int amdgpu_vm_lock_pd(struct amdgpu_vm *vm, struct drm_exec *exec,
418 		      unsigned int num_fences);
419 bool amdgpu_vm_ready(struct amdgpu_vm *vm);
420 uint64_t amdgpu_vm_generation(struct amdgpu_device *adev, struct amdgpu_vm *vm);
421 int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
422 			      int (*callback)(void *p, struct amdgpu_bo *bo),
423 			      void *param);
424 int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job, bool need_pipe_sync);
425 int amdgpu_vm_update_pdes(struct amdgpu_device *adev,
426 			  struct amdgpu_vm *vm, bool immediate);
427 int amdgpu_vm_clear_freed(struct amdgpu_device *adev,
428 			  struct amdgpu_vm *vm,
429 			  struct dma_fence **fence);
430 int amdgpu_vm_handle_moved(struct amdgpu_device *adev,
431 			   struct amdgpu_vm *vm);
432 void amdgpu_vm_bo_base_init(struct amdgpu_vm_bo_base *base,
433 			    struct amdgpu_vm *vm, struct amdgpu_bo *bo);
434 int amdgpu_vm_update_range(struct amdgpu_device *adev, struct amdgpu_vm *vm,
435 			   bool immediate, bool unlocked, bool flush_tlb,
436 			   struct dma_resv *resv, uint64_t start, uint64_t last,
437 			   uint64_t flags, uint64_t offset, uint64_t vram_base,
438 			   struct ttm_resource *res, dma_addr_t *pages_addr,
439 			   struct dma_fence **fence);
440 int amdgpu_vm_bo_update(struct amdgpu_device *adev,
441 			struct amdgpu_bo_va *bo_va,
442 			bool clear);
443 bool amdgpu_vm_evictable(struct amdgpu_bo *bo);
444 void amdgpu_vm_bo_invalidate(struct amdgpu_device *adev,
445 			     struct amdgpu_bo *bo, bool evicted);
446 uint64_t amdgpu_vm_map_gart(const dma_addr_t *pages_addr, uint64_t addr);
447 struct amdgpu_bo_va *amdgpu_vm_bo_find(struct amdgpu_vm *vm,
448 				       struct amdgpu_bo *bo);
449 struct amdgpu_bo_va *amdgpu_vm_bo_add(struct amdgpu_device *adev,
450 				      struct amdgpu_vm *vm,
451 				      struct amdgpu_bo *bo);
452 int amdgpu_vm_bo_map(struct amdgpu_device *adev,
453 		     struct amdgpu_bo_va *bo_va,
454 		     uint64_t addr, uint64_t offset,
455 		     uint64_t size, uint64_t flags);
456 int amdgpu_vm_bo_replace_map(struct amdgpu_device *adev,
457 			     struct amdgpu_bo_va *bo_va,
458 			     uint64_t addr, uint64_t offset,
459 			     uint64_t size, uint64_t flags);
460 int amdgpu_vm_bo_unmap(struct amdgpu_device *adev,
461 		       struct amdgpu_bo_va *bo_va,
462 		       uint64_t addr);
463 int amdgpu_vm_bo_clear_mappings(struct amdgpu_device *adev,
464 				struct amdgpu_vm *vm,
465 				uint64_t saddr, uint64_t size);
466 struct amdgpu_bo_va_mapping *amdgpu_vm_bo_lookup_mapping(struct amdgpu_vm *vm,
467 							 uint64_t addr);
468 void amdgpu_vm_bo_trace_cs(struct amdgpu_vm *vm, struct ww_acquire_ctx *ticket);
469 void amdgpu_vm_bo_del(struct amdgpu_device *adev,
470 		      struct amdgpu_bo_va *bo_va);
471 void amdgpu_vm_adjust_size(struct amdgpu_device *adev, uint32_t min_vm_size,
472 			   uint32_t fragment_size_default, unsigned max_level,
473 			   unsigned max_bits);
474 int amdgpu_vm_ioctl(struct drm_device *dev, void *data, struct drm_file *filp);
475 bool amdgpu_vm_need_pipeline_sync(struct amdgpu_ring *ring,
476 				  struct amdgpu_job *job);
477 void amdgpu_vm_check_compute_bug(struct amdgpu_device *adev);
478 
479 void amdgpu_vm_get_task_info(struct amdgpu_device *adev, u32 pasid,
480 			     struct amdgpu_task_info *task_info);
481 bool amdgpu_vm_handle_fault(struct amdgpu_device *adev, u32 pasid,
482 			    u32 vmid, u32 node_id, uint64_t addr,
483 			    bool write_fault);
484 
485 void amdgpu_vm_set_task_info(struct amdgpu_vm *vm);
486 
487 void amdgpu_vm_move_to_lru_tail(struct amdgpu_device *adev,
488 				struct amdgpu_vm *vm);
489 void amdgpu_vm_get_memory(struct amdgpu_vm *vm,
490 			  struct amdgpu_mem_stats *stats);
491 
492 int amdgpu_vm_pt_clear(struct amdgpu_device *adev, struct amdgpu_vm *vm,
493 		       struct amdgpu_bo_vm *vmbo, bool immediate);
494 int amdgpu_vm_pt_create(struct amdgpu_device *adev, struct amdgpu_vm *vm,
495 			int level, bool immediate, struct amdgpu_bo_vm **vmbo,
496 			int32_t xcp_id);
497 void amdgpu_vm_pt_free_root(struct amdgpu_device *adev, struct amdgpu_vm *vm);
498 bool amdgpu_vm_pt_is_root_clean(struct amdgpu_device *adev,
499 				struct amdgpu_vm *vm);
500 
501 int amdgpu_vm_pde_update(struct amdgpu_vm_update_params *params,
502 			 struct amdgpu_vm_bo_base *entry);
503 int amdgpu_vm_ptes_update(struct amdgpu_vm_update_params *params,
504 			  uint64_t start, uint64_t end,
505 			  uint64_t dst, uint64_t flags);
506 void amdgpu_vm_pt_free_work(struct work_struct *work);
507 
508 #if defined(CONFIG_DEBUG_FS)
509 void amdgpu_debugfs_vm_bo_info(struct amdgpu_vm *vm, struct seq_file *m);
510 #endif
511 
512 int amdgpu_vm_pt_map_tables(struct amdgpu_device *adev, struct amdgpu_vm *vm);
513 
514 /**
515  * amdgpu_vm_tlb_seq - return tlb flush sequence number
516  * @vm: the amdgpu_vm structure to query
517  *
518  * Returns the tlb flush sequence number which indicates that the VM TLBs needs
519  * to be invalidated whenever the sequence number change.
520  */
amdgpu_vm_tlb_seq(struct amdgpu_vm * vm)521 static inline uint64_t amdgpu_vm_tlb_seq(struct amdgpu_vm *vm)
522 {
523 	unsigned long flags;
524 	spinlock_t *lock;
525 
526 	/*
527 	 * Workaround to stop racing between the fence signaling and handling
528 	 * the cb. The lock is static after initially setting it up, just make
529 	 * sure that the dma_fence structure isn't freed up.
530 	 */
531 	rcu_read_lock();
532 	lock = vm->last_tlb_flush->lock;
533 	rcu_read_unlock();
534 
535 	spin_lock_irqsave(lock, flags);
536 	spin_unlock_irqrestore(lock, flags);
537 
538 	return atomic64_read(&vm->tlb_seq);
539 }
540 
541 /*
542  * vm eviction_lock can be taken in MMU notifiers. Make sure no reclaim-FS
543  * happens while holding this lock anywhere to prevent deadlocks when
544  * an MMU notifier runs in reclaim-FS context.
545  */
amdgpu_vm_eviction_lock(struct amdgpu_vm * vm)546 static inline void amdgpu_vm_eviction_lock(struct amdgpu_vm *vm)
547 {
548 	mutex_lock(&vm->eviction_lock);
549 #ifdef notyet
550 	vm->saved_flags = memalloc_noreclaim_save();
551 #endif
552 }
553 
amdgpu_vm_eviction_trylock(struct amdgpu_vm * vm)554 static inline bool amdgpu_vm_eviction_trylock(struct amdgpu_vm *vm)
555 {
556 	if (mutex_trylock(&vm->eviction_lock)) {
557 #ifdef notyet
558 		vm->saved_flags = memalloc_noreclaim_save();
559 #endif
560 		return true;
561 	}
562 	return false;
563 }
564 
amdgpu_vm_eviction_unlock(struct amdgpu_vm * vm)565 static inline void amdgpu_vm_eviction_unlock(struct amdgpu_vm *vm)
566 {
567 #ifdef notyet
568 	memalloc_noreclaim_restore(vm->saved_flags);
569 #endif
570 	mutex_unlock(&vm->eviction_lock);
571 }
572 
573 #endif
574