1/*
  2 * SPDX-License-Identifier: MIT
  3 *
  4 * Copyright © 2019 Intel Corporation
  5 */
  6
  7#include "gem/i915_gem_context.h"
  8#include "gem/i915_gem_pm.h"
  9
 10#include "i915_drv.h"
 11#include "i915_globals.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 i915_global_context {
 19	struct i915_global base;
 20	struct kmem_cache *slab_ce;
 21} global;
 22
 23static struct intel_context *intel_context_alloc(void)
 24{
 25	return kmem_cache_zalloc(global.slab_ce, GFP_KERNEL);
 26}
 27
 28void intel_context_free(struct intel_context *ce)
 29{
 30	kmem_cache_free(global.slab_ce, ce);
 31}
 32
 33struct intel_context *
 34intel_context_create(struct intel_engine_cs *engine)
 35{
 36	struct intel_context *ce;
 37
 38	ce = intel_context_alloc();
 39	if (!ce)
 40		return ERR_PTR(-ENOMEM);
 41
 42	intel_context_init(ce, engine);
 43	return ce;
 44}
 45
 46int intel_context_alloc_state(struct intel_context *ce)
 47{
 48	int err = 0;
 49
 50	if (mutex_lock_interruptible(&ce->pin_mutex))
 51		return -EINTR;
 52
 53	if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
 54		if (intel_context_is_banned(ce)) {
 55			err = -EIO;
 56			goto unlock;
 57		}
 58
 59		err = ce->ops->alloc(ce);
 60		if (unlikely(err))
 61			goto unlock;
 62
 63		set_bit(CONTEXT_ALLOC_BIT, &ce->flags);
 64	}
 65
 66unlock:
 67	mutex_unlock(&ce->pin_mutex);
 68	return err;
 69}
 70
 71static int intel_context_active_acquire(struct intel_context *ce)
 72{
 73	int err;
 74
 75	__i915_active_acquire(&ce->active);
 76
 77	if (intel_context_is_barrier(ce))
 78		return 0;
 79
 80	/* Preallocate tracking nodes */
 81	err = i915_active_acquire_preallocate_barrier(&ce->active,
 82						      ce->engine);
 83	if (err)
 84		i915_active_release(&ce->active);
 85
 86	return err;
 87}
 88
 89static void intel_context_active_release(struct intel_context *ce)
 90{
 91	/* Nodes preallocated in intel_context_active() */
 92	i915_active_acquire_barrier(&ce->active);
 93	i915_active_release(&ce->active);
 94}
 95
 96int __intel_context_do_pin(struct intel_context *ce)
 97{
 98	int err;
 99
100	if (unlikely(!test_bit(CONTEXT_ALLOC_BIT, &ce->flags))) {
101		err = intel_context_alloc_state(ce);
102		if (err)
103			return err;
104	}
105
106	err = i915_active_acquire(&ce->active);
107	if (err)
108		return err;
109
110	if (mutex_lock_interruptible(&ce->pin_mutex)) {
111		err = -EINTR;
112		goto out_release;
113	}
114
115	if (unlikely(intel_context_is_closed(ce))) {
116		err = -ENOENT;
117		goto out_unlock;
118	}
119
120	if (likely(!atomic_add_unless(&ce->pin_count, 1, 0))) {
121		err = intel_context_active_acquire(ce);
122		if (unlikely(err))
123			goto out_unlock;
124
125		err = ce->ops->pin(ce);
126		if (unlikely(err))
127			goto err_active;
128
129		CE_TRACE(ce, "pin ring:{start:%08x, head:%04x, tail:%04x}\n",
130			 i915_ggtt_offset(ce->ring->vma),
131			 ce->ring->head, ce->ring->tail);
132
133		smp_mb__before_atomic(); /* flush pin before it is visible */
134		atomic_inc(&ce->pin_count);
135	}
136
137	GEM_BUG_ON(!intel_context_is_pinned(ce)); /* no overflow! */
138	GEM_BUG_ON(i915_active_is_idle(&ce->active));
139	goto out_unlock;
140
141err_active:
142	intel_context_active_release(ce);
143out_unlock:
144	mutex_unlock(&ce->pin_mutex);
145out_release:
146	i915_active_release(&ce->active);
147	return err;
148}
149
150void intel_context_unpin(struct intel_context *ce)
151{
152	if (!atomic_dec_and_test(&ce->pin_count))
153		return;
154
155	CE_TRACE(ce, "unpin\n");
156	ce->ops->unpin(ce);
157
158	/*
159	 * Once released, we may asynchronously drop the active reference.
160	 * As that may be the only reference keeping the context alive,
161	 * take an extra now so that it is not freed before we finish
162	 * dereferencing it.
163	 */
164	intel_context_get(ce);
165	intel_context_active_release(ce);
166	intel_context_put(ce);
167}
168
169static int __context_pin_state(struct i915_vma *vma)
170{
171	unsigned int bias = i915_ggtt_pin_bias(vma) | PIN_OFFSET_BIAS;
172	int err;
173
174	err = i915_ggtt_pin(vma, 0, bias | PIN_HIGH);
175	if (err)
176		return err;
177
178	err = i915_active_acquire(&vma->active);
179	if (err)
180		goto err_unpin;
181
182	/*
183	 * And mark it as a globally pinned object to let the shrinker know
184	 * it cannot reclaim the object until we release it.
185	 */
186	i915_vma_make_unshrinkable(vma);
187	vma->obj->mm.dirty = true;
188
189	return 0;
190
191err_unpin:
192	i915_vma_unpin(vma);
193	return err;
194}
195
196static void __context_unpin_state(struct i915_vma *vma)
197{
198	i915_vma_make_shrinkable(vma);
199	i915_active_release(&vma->active);
200	__i915_vma_unpin(vma);
201}
202
203static int __ring_active(struct intel_ring *ring)
204{
205	int err;
206
207	err = intel_ring_pin(ring);
208	if (err)
209		return err;
210
211	err = i915_active_acquire(&ring->vma->active);
212	if (err)
213		goto err_pin;
214
215	return 0;
216
217err_pin:
218	intel_ring_unpin(ring);
219	return err;
220}
221
222static void __ring_retire(struct intel_ring *ring)
223{
224	i915_active_release(&ring->vma->active);
225	intel_ring_unpin(ring);
226}
227
228__i915_active_call
229static void __intel_context_retire(struct i915_active *active)
230{
231	struct intel_context *ce = container_of(active, typeof(*ce), active);
232
233	CE_TRACE(ce, "retire runtime: { total:%lluns, avg:%lluns }\n",
234		 intel_context_get_total_runtime_ns(ce),
235		 intel_context_get_avg_runtime_ns(ce));
236
237	set_bit(CONTEXT_VALID_BIT, &ce->flags);
238	if (ce->state)
239		__context_unpin_state(ce->state);
240
241	intel_timeline_unpin(ce->timeline);
242	__ring_retire(ce->ring);
243
244	intel_context_put(ce);
245}
246
247static int __intel_context_active(struct i915_active *active)
248{
249	struct intel_context *ce = container_of(active, typeof(*ce), active);
250	int err;
251
252	CE_TRACE(ce, "active\n");
253
254	intel_context_get(ce);
255
256	err = __ring_active(ce->ring);
257	if (err)
258		goto err_put;
259
260	err = intel_timeline_pin(ce->timeline);
261	if (err)
262		goto err_ring;
263
264	if (!ce->state)
265		return 0;
266
267	err = __context_pin_state(ce->state);
268	if (err)
269		goto err_timeline;
270
271	return 0;
272
273err_timeline:
274	intel_timeline_unpin(ce->timeline);
275err_ring:
276	__ring_retire(ce->ring);
277err_put:
278	intel_context_put(ce);
279	return err;
280}
281
282void
283intel_context_init(struct intel_context *ce,
284		   struct intel_engine_cs *engine)
285{
286	GEM_BUG_ON(!engine->cops);
287	GEM_BUG_ON(!engine->gt->vm);
288
289	kref_init(&ce->ref);
290
291	ce->engine = engine;
292	ce->ops = engine->cops;
293	ce->sseu = engine->sseu;
294	ce->ring = __intel_context_ring_size(SZ_4K);
295
296	ewma_runtime_init(&ce->runtime.avg);
297
298	ce->vm = i915_vm_get(engine->gt->vm);
299
300	INIT_LIST_HEAD(&ce->signal_link);
301	INIT_LIST_HEAD(&ce->signals);
302
303	mutex_init(&ce->pin_mutex);
304
305	i915_active_init(&ce->active,
306			 __intel_context_active, __intel_context_retire);
307}
308
309void intel_context_fini(struct intel_context *ce)
310{
311	if (ce->timeline)
312		intel_timeline_put(ce->timeline);
313	i915_vm_put(ce->vm);
314
315	mutex_destroy(&ce->pin_mutex);
316	i915_active_fini(&ce->active);
317}
318
319static void i915_global_context_shrink(void)
320{
321	kmem_cache_shrink(global.slab_ce);
322}
323
324static void i915_global_context_exit(void)
325{
326	kmem_cache_destroy(global.slab_ce);
327}
328
329static struct i915_global_context global = { {
330	.shrink = i915_global_context_shrink,
331	.exit = i915_global_context_exit,
332} };
333
334int __init i915_global_context_init(void)
335{
336	global.slab_ce = KMEM_CACHE(intel_context, SLAB_HWCACHE_ALIGN);
337	if (!global.slab_ce)
338		return -ENOMEM;
339
340	i915_global_register(&global.base);
341	return 0;
342}
343
344void intel_context_enter_engine(struct intel_context *ce)
345{
346	intel_engine_pm_get(ce->engine);
347	intel_timeline_enter(ce->timeline);
348}
349
350void intel_context_exit_engine(struct intel_context *ce)
351{
352	intel_timeline_exit(ce->timeline);
353	intel_engine_pm_put(ce->engine);
354}
355
356int intel_context_prepare_remote_request(struct intel_context *ce,
357					 struct i915_request *rq)
358{
359	struct intel_timeline *tl = ce->timeline;
360	int err;
361
362	/* Only suitable for use in remotely modifying this context */
363	GEM_BUG_ON(rq->context == ce);
364
365	if (rcu_access_pointer(rq->timeline) != tl) { /* timeline sharing! */
366		/* Queue this switch after current activity by this context. */
367		err = i915_active_fence_set(&tl->last_request, rq);
368		if (err)
369			return err;
370	}
371
372	/*
373	 * Guarantee context image and the timeline remains pinned until the
374	 * modifying request is retired by setting the ce activity tracker.
375	 *
376	 * But we only need to take one pin on the account of it. Or in other
377	 * words transfer the pinned ce object to tracked active request.
378	 */
379	GEM_BUG_ON(i915_active_is_idle(&ce->active));
380	return i915_active_add_request(&ce->active, rq);
381}
382
383struct i915_request *intel_context_create_request(struct intel_context *ce)
384{
385	struct i915_request *rq;
386	int err;
387
388	err = intel_context_pin(ce);
389	if (unlikely(err))
390		return ERR_PTR(err);
391
392	rq = i915_request_create(ce);
393	intel_context_unpin(ce);
394
395	return rq;
396}
397
398#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
399#include "selftest_context.c"
400#endif