1// SPDX-License-Identifier: MIT
2/*
3 * Copyright �� 2019 Intel Corporation
4 */
5
6#include "gem/i915_gem_context.h"
7#include "gem/i915_gem_pm.h"
8
9#include "i915_drm_client.h"
10#include "i915_drv.h"
11#include "i915_trace.h"
12
13#include "intel_context.h"
14#include "intel_engine.h"
15#include "intel_engine_pm.h"
16#include "intel_ring.h"
17
18static struct kmem_cache *slab_ce;
19
20static struct intel_context *intel_context_alloc(void)
21{
22	return kmem_cache_zalloc(slab_ce, GFP_KERNEL);
23}
24
25static void rcu_context_free(struct rcu_head *rcu)
26{
27	struct intel_context *ce = container_of(rcu, typeof(*ce), rcu);
28
29	trace_intel_context_free(ce);
30	kmem_cache_free(slab_ce, ce);
31}
32
33void intel_context_free(struct intel_context *ce)
34{
35	call_rcu(&ce->rcu, rcu_context_free);
36}
37
38struct intel_context *
39intel_context_create(struct intel_engine_cs *engine)
40{
41	struct intel_context *ce;
42
43	ce = intel_context_alloc();
44	if (!ce)
45		return ERR_PTR(-ENOMEM);
46
47	intel_context_init(ce, engine);
48	trace_intel_context_create(ce);
49	return ce;
50}
51
52int intel_context_alloc_state(struct intel_context *ce)
53{
54	struct i915_gem_context *ctx;
55	int err = 0;
56
57	if (mutex_lock_interruptible(&ce->pin_mutex))
58		return -EINTR;
59
60	if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
61		if (intel_context_is_banned(ce)) {
62			err = -EIO;
63			goto unlock;
64		}
65
66		err = ce->ops->alloc(ce);
67		if (unlikely(err))
68			goto unlock;
69
70		set_bit(CONTEXT_ALLOC_BIT, &ce->flags);
71
72		rcu_read_lock();
73		ctx = rcu_dereference(ce->gem_context);
74		if (ctx && !kref_get_unless_zero(&ctx->ref))
75			ctx = NULL;
76		rcu_read_unlock();
77		if (ctx) {
78			if (ctx->client)
79				i915_drm_client_add_context_objects(ctx->client,
80								    ce);
81			i915_gem_context_put(ctx);
82		}
83	}
84
85unlock:
86	mutex_unlock(&ce->pin_mutex);
87	return err;
88}
89
90static int intel_context_active_acquire(struct intel_context *ce)
91{
92	int err;
93
94	__i915_active_acquire(&ce->active);
95
96	if (intel_context_is_barrier(ce) || intel_engine_uses_guc(ce->engine) ||
97	    intel_context_is_parallel(ce))
98		return 0;
99
100	/* Preallocate tracking nodes */
101	err = i915_active_acquire_preallocate_barrier(&ce->active,
102						      ce->engine);
103	if (err)
104		i915_active_release(&ce->active);
105
106	return err;
107}
108
109static void intel_context_active_release(struct intel_context *ce)
110{
111	/* Nodes preallocated in intel_context_active() */
112	i915_active_acquire_barrier(&ce->active);
113	i915_active_release(&ce->active);
114}
115
116static int __context_pin_state(struct i915_vma *vma, struct i915_gem_ww_ctx *ww)
117{
118	unsigned int bias = i915_ggtt_pin_bias(vma) | PIN_OFFSET_BIAS;
119	int err;
120
121	err = i915_ggtt_pin(vma, ww, 0, bias | PIN_HIGH);
122	if (err)
123		return err;
124
125	err = i915_active_acquire(&vma->active);
126	if (err)
127		goto err_unpin;
128
129	/*
130	 * And mark it as a globally pinned object to let the shrinker know
131	 * it cannot reclaim the object until we release it.
132	 */
133	i915_vma_make_unshrinkable(vma);
134	vma->obj->mm.dirty = true;
135
136	return 0;
137
138err_unpin:
139	i915_vma_unpin(vma);
140	return err;
141}
142
143static void __context_unpin_state(struct i915_vma *vma)
144{
145	i915_vma_make_shrinkable(vma);
146	i915_active_release(&vma->active);
147	__i915_vma_unpin(vma);
148}
149
150static int __ring_active(struct intel_ring *ring,
151			 struct i915_gem_ww_ctx *ww)
152{
153	int err;
154
155	err = intel_ring_pin(ring, ww);
156	if (err)
157		return err;
158
159	err = i915_active_acquire(&ring->vma->active);
160	if (err)
161		goto err_pin;
162
163	return 0;
164
165err_pin:
166	intel_ring_unpin(ring);
167	return err;
168}
169
170static void __ring_retire(struct intel_ring *ring)
171{
172	i915_active_release(&ring->vma->active);
173	intel_ring_unpin(ring);
174}
175
176static int intel_context_pre_pin(struct intel_context *ce,
177				 struct i915_gem_ww_ctx *ww)
178{
179	int err;
180
181	CE_TRACE(ce, "active\n");
182
183	err = __ring_active(ce->ring, ww);
184	if (err)
185		return err;
186
187	err = intel_timeline_pin(ce->timeline, ww);
188	if (err)
189		goto err_ring;
190
191	if (!ce->state)
192		return 0;
193
194	err = __context_pin_state(ce->state, ww);
195	if (err)
196		goto err_timeline;
197
198
199	return 0;
200
201err_timeline:
202	intel_timeline_unpin(ce->timeline);
203err_ring:
204	__ring_retire(ce->ring);
205	return err;
206}
207
208static void intel_context_post_unpin(struct intel_context *ce)
209{
210	if (ce->state)
211		__context_unpin_state(ce->state);
212
213	intel_timeline_unpin(ce->timeline);
214	__ring_retire(ce->ring);
215}
216
217int __intel_context_do_pin_ww(struct intel_context *ce,
218			      struct i915_gem_ww_ctx *ww)
219{
220	bool handoff = false;
221	void *vaddr;
222	int err = 0;
223
224	if (unlikely(!test_bit(CONTEXT_ALLOC_BIT, &ce->flags))) {
225		err = intel_context_alloc_state(ce);
226		if (err)
227			return err;
228	}
229
230	/*
231	 * We always pin the context/ring/timeline here, to ensure a pin
232	 * refcount for __intel_context_active(), which prevent a lock
233	 * inversion of ce->pin_mutex vs dma_resv_lock().
234	 */
235
236	err = i915_gem_object_lock(ce->timeline->hwsp_ggtt->obj, ww);
237	if (!err)
238		err = i915_gem_object_lock(ce->ring->vma->obj, ww);
239	if (!err && ce->state)
240		err = i915_gem_object_lock(ce->state->obj, ww);
241	if (!err)
242		err = intel_context_pre_pin(ce, ww);
243	if (err)
244		return err;
245
246	err = ce->ops->pre_pin(ce, ww, &vaddr);
247	if (err)
248		goto err_ctx_unpin;
249
250	err = i915_active_acquire(&ce->active);
251	if (err)
252		goto err_post_unpin;
253
254	err = mutex_lock_interruptible(&ce->pin_mutex);
255	if (err)
256		goto err_release;
257
258	intel_engine_pm_might_get(ce->engine);
259
260	if (unlikely(intel_context_is_closed(ce))) {
261		err = -ENOENT;
262		goto err_unlock;
263	}
264
265	if (likely(!atomic_add_unless(&ce->pin_count, 1, 0))) {
266		err = intel_context_active_acquire(ce);
267		if (unlikely(err))
268			goto err_unlock;
269
270		err = ce->ops->pin(ce, vaddr);
271		if (err) {
272			intel_context_active_release(ce);
273			goto err_unlock;
274		}
275
276		CE_TRACE(ce, "pin ring:{start:%08x, head:%04x, tail:%04x}\n",
277			 i915_ggtt_offset(ce->ring->vma),
278			 ce->ring->head, ce->ring->tail);
279
280		handoff = true;
281		smp_mb__before_atomic(); /* flush pin before it is visible */
282		atomic_inc(&ce->pin_count);
283	}
284
285	GEM_BUG_ON(!intel_context_is_pinned(ce)); /* no overflow! */
286
287	trace_intel_context_do_pin(ce);
288
289err_unlock:
290	mutex_unlock(&ce->pin_mutex);
291err_release:
292	i915_active_release(&ce->active);
293err_post_unpin:
294	if (!handoff)
295		ce->ops->post_unpin(ce);
296err_ctx_unpin:
297	intel_context_post_unpin(ce);
298
299	/*
300	 * Unlock the hwsp_ggtt object since it's shared.
301	 * In principle we can unlock all the global state locked above
302	 * since it's pinned and doesn't need fencing, and will
303	 * thus remain resident until it is explicitly unpinned.
304	 */
305	i915_gem_ww_unlock_single(ce->timeline->hwsp_ggtt->obj);
306
307	return err;
308}
309
310int __intel_context_do_pin(struct intel_context *ce)
311{
312	struct i915_gem_ww_ctx ww;
313	int err;
314
315	i915_gem_ww_ctx_init(&ww, true);
316retry:
317	err = __intel_context_do_pin_ww(ce, &ww);
318	if (err == -EDEADLK) {
319		err = i915_gem_ww_ctx_backoff(&ww);
320		if (!err)
321			goto retry;
322	}
323	i915_gem_ww_ctx_fini(&ww);
324	return err;
325}
326
327void __intel_context_do_unpin(struct intel_context *ce, int sub)
328{
329	if (!atomic_sub_and_test(sub, &ce->pin_count))
330		return;
331
332	CE_TRACE(ce, "unpin\n");
333	ce->ops->unpin(ce);
334	ce->ops->post_unpin(ce);
335
336	/*
337	 * Once released, we may asynchronously drop the active reference.
338	 * As that may be the only reference keeping the context alive,
339	 * take an extra now so that it is not freed before we finish
340	 * dereferencing it.
341	 */
342	intel_context_get(ce);
343	intel_context_active_release(ce);
344	trace_intel_context_do_unpin(ce);
345	intel_context_put(ce);
346}
347
348static void __intel_context_retire(struct i915_active *active)
349{
350	struct intel_context *ce = container_of(active, typeof(*ce), active);
351
352	CE_TRACE(ce, "retire runtime: { total:%lluns, avg:%lluns }\n",
353		 intel_context_get_total_runtime_ns(ce),
354		 intel_context_get_avg_runtime_ns(ce));
355
356	set_bit(CONTEXT_VALID_BIT, &ce->flags);
357	intel_context_post_unpin(ce);
358	intel_context_put(ce);
359}
360
361static int __intel_context_active(struct i915_active *active)
362{
363	struct intel_context *ce = container_of(active, typeof(*ce), active);
364
365	intel_context_get(ce);
366
367	/* everything should already be activated by intel_context_pre_pin() */
368	GEM_WARN_ON(!i915_active_acquire_if_busy(&ce->ring->vma->active));
369	__intel_ring_pin(ce->ring);
370
371	__intel_timeline_pin(ce->timeline);
372
373	if (ce->state) {
374		GEM_WARN_ON(!i915_active_acquire_if_busy(&ce->state->active));
375		__i915_vma_pin(ce->state);
376		i915_vma_make_unshrinkable(ce->state);
377	}
378
379	return 0;
380}
381
382static int
383sw_fence_dummy_notify(struct i915_sw_fence *sf,
384		      enum i915_sw_fence_notify state)
385{
386	return NOTIFY_DONE;
387}
388
389void
390intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
391{
392	GEM_BUG_ON(!engine->cops);
393	GEM_BUG_ON(!engine->gt->vm);
394
395	kref_init(&ce->ref);
396
397	ce->engine = engine;
398	ce->ops = engine->cops;
399	ce->sseu = engine->sseu;
400	ce->ring = NULL;
401	ce->ring_size = SZ_4K;
402
403	ewma_runtime_init(&ce->stats.runtime.avg);
404
405	ce->vm = i915_vm_get(engine->gt->vm);
406
407	/* NB ce->signal_link/lock is used under RCU */
408	spin_lock_init(&ce->signal_lock);
409	INIT_LIST_HEAD(&ce->signals);
410
411	mutex_init(&ce->pin_mutex);
412
413	spin_lock_init(&ce->guc_state.lock);
414	INIT_LIST_HEAD(&ce->guc_state.fences);
415	INIT_LIST_HEAD(&ce->guc_state.requests);
416
417	ce->guc_id.id = GUC_INVALID_CONTEXT_ID;
418	INIT_LIST_HEAD(&ce->guc_id.link);
419
420	INIT_LIST_HEAD(&ce->destroyed_link);
421
422	INIT_LIST_HEAD(&ce->parallel.child_list);
423
424	/*
425	 * Initialize fence to be complete as this is expected to be complete
426	 * unless there is a pending schedule disable outstanding.
427	 */
428	i915_sw_fence_init(&ce->guc_state.blocked,
429			   sw_fence_dummy_notify);
430	i915_sw_fence_commit(&ce->guc_state.blocked);
431
432	i915_active_init(&ce->active,
433			 __intel_context_active, __intel_context_retire, 0);
434}
435
436void intel_context_fini(struct intel_context *ce)
437{
438	struct intel_context *child, *next;
439
440	if (ce->timeline)
441		intel_timeline_put(ce->timeline);
442	i915_vm_put(ce->vm);
443
444	/* Need to put the creation ref for the children */
445	if (intel_context_is_parent(ce))
446		for_each_child_safe(ce, child, next)
447			intel_context_put(child);
448
449	mutex_destroy(&ce->pin_mutex);
450	i915_active_fini(&ce->active);
451	i915_sw_fence_fini(&ce->guc_state.blocked);
452}
453
454void i915_context_module_exit(void)
455{
456	kmem_cache_destroy(slab_ce);
457}
458
459int __init i915_context_module_init(void)
460{
461	slab_ce = KMEM_CACHE(intel_context, SLAB_HWCACHE_ALIGN);
462	if (!slab_ce)
463		return -ENOMEM;
464
465	return 0;
466}
467
468void intel_context_enter_engine(struct intel_context *ce)
469{
470	intel_engine_pm_get(ce->engine);
471	intel_timeline_enter(ce->timeline);
472}
473
474void intel_context_exit_engine(struct intel_context *ce)
475{
476	intel_timeline_exit(ce->timeline);
477	intel_engine_pm_put(ce->engine);
478}
479
480int intel_context_prepare_remote_request(struct intel_context *ce,
481					 struct i915_request *rq)
482{
483	struct intel_timeline *tl = ce->timeline;
484	int err;
485
486	/* Only suitable for use in remotely modifying this context */
487	GEM_BUG_ON(rq->context == ce);
488
489	if (rcu_access_pointer(rq->timeline) != tl) { /* timeline sharing! */
490		/* Queue this switch after current activity by this context. */
491		err = i915_active_fence_set(&tl->last_request, rq);
492		if (err)
493			return err;
494	}
495
496	/*
497	 * Guarantee context image and the timeline remains pinned until the
498	 * modifying request is retired by setting the ce activity tracker.
499	 *
500	 * But we only need to take one pin on the account of it. Or in other
501	 * words transfer the pinned ce object to tracked active request.
502	 */
503	GEM_BUG_ON(i915_active_is_idle(&ce->active));
504	return i915_active_add_request(&ce->active, rq);
505}
506
507struct i915_request *intel_context_create_request(struct intel_context *ce)
508{
509	struct i915_gem_ww_ctx ww;
510	struct i915_request *rq;
511	int err;
512
513	i915_gem_ww_ctx_init(&ww, true);
514retry:
515	err = intel_context_pin_ww(ce, &ww);
516	if (!err) {
517		rq = i915_request_create(ce);
518		intel_context_unpin(ce);
519	} else if (err == -EDEADLK) {
520		err = i915_gem_ww_ctx_backoff(&ww);
521		if (!err)
522			goto retry;
523		rq = ERR_PTR(err);
524	} else {
525		rq = ERR_PTR(err);
526	}
527
528	i915_gem_ww_ctx_fini(&ww);
529
530	if (IS_ERR(rq))
531		return rq;
532
533	/*
534	 * timeline->mutex should be the inner lock, but is used as outer lock.
535	 * Hack around this to shut up lockdep in selftests..
536	 */
537	lockdep_unpin_lock(&ce->timeline->mutex, rq->cookie);
538	mutex_release(&ce->timeline->mutex.dep_map, _RET_IP_);
539	mutex_acquire(&ce->timeline->mutex.dep_map, SINGLE_DEPTH_NESTING, 0, _RET_IP_);
540	rq->cookie = lockdep_pin_lock(&ce->timeline->mutex);
541
542	return rq;
543}
544
545struct i915_request *intel_context_get_active_request(struct intel_context *ce)
546{
547	struct intel_context *parent = intel_context_to_parent(ce);
548	struct i915_request *rq, *active = NULL;
549	unsigned long flags;
550
551	GEM_BUG_ON(!intel_engine_uses_guc(ce->engine));
552
553	/*
554	 * We search the parent list to find an active request on the submitted
555	 * context. The parent list contains the requests for all the contexts
556	 * in the relationship so we have to do a compare of each request's
557	 * context.
558	 */
559	spin_lock_irqsave(&parent->guc_state.lock, flags);
560	list_for_each_entry_reverse(rq, &parent->guc_state.requests,
561				    sched.link) {
562		if (rq->context != ce)
563			continue;
564		if (i915_request_completed(rq))
565			break;
566
567		active = rq;
568	}
569	if (active)
570		active = i915_request_get_rcu(active);
571	spin_unlock_irqrestore(&parent->guc_state.lock, flags);
572
573	return active;
574}
575
576void intel_context_bind_parent_child(struct intel_context *parent,
577				     struct intel_context *child)
578{
579	/*
580	 * Callers responsibility to validate that this function is used
581	 * correctly but we use GEM_BUG_ON here ensure that they do.
582	 */
583	GEM_BUG_ON(intel_context_is_pinned(parent));
584	GEM_BUG_ON(intel_context_is_child(parent));
585	GEM_BUG_ON(intel_context_is_pinned(child));
586	GEM_BUG_ON(intel_context_is_child(child));
587	GEM_BUG_ON(intel_context_is_parent(child));
588
589	parent->parallel.child_index = parent->parallel.number_children++;
590	list_add_tail(&child->parallel.child_link,
591		      &parent->parallel.child_list);
592	child->parallel.parent = parent;
593}
594
595u64 intel_context_get_total_runtime_ns(struct intel_context *ce)
596{
597	u64 total, active;
598
599	if (ce->ops->update_stats)
600		ce->ops->update_stats(ce);
601
602	total = ce->stats.runtime.total;
603	if (ce->ops->flags & COPS_RUNTIME_CYCLES)
604		total *= ce->engine->gt->clock_period_ns;
605
606	active = READ_ONCE(ce->stats.active);
607	if (active)
608		active = intel_context_clock() - active;
609
610	return total + active;
611}
612
613u64 intel_context_get_avg_runtime_ns(struct intel_context *ce)
614{
615	u64 avg = ewma_runtime_read(&ce->stats.runtime.avg);
616
617	if (ce->ops->flags & COPS_RUNTIME_CYCLES)
618		avg *= ce->engine->gt->clock_period_ns;
619
620	return avg;
621}
622
623bool intel_context_ban(struct intel_context *ce, struct i915_request *rq)
624{
625	bool ret = intel_context_set_banned(ce);
626
627	trace_intel_context_ban(ce);
628
629	if (ce->ops->revoke)
630		ce->ops->revoke(ce, rq,
631				INTEL_CONTEXT_BANNED_PREEMPT_TIMEOUT_MS);
632
633	return ret;
634}
635
636bool intel_context_revoke(struct intel_context *ce)
637{
638	bool ret = intel_context_set_exiting(ce);
639
640	if (ce->ops->revoke)
641		ce->ops->revoke(ce, NULL, ce->engine->props.preempt_timeout_ms);
642
643	return ret;
644}
645
646#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
647#include "selftest_context.c"
648#endif
649