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 
18 static struct i915_global_context {
19 	struct i915_global base;
20 	struct kmem_cache *slab_ce;
21 } global;
22 
23 static struct intel_context *intel_context_alloc(void)
24 {
25 	return kmem_cache_zalloc(global.slab_ce, GFP_KERNEL);
26 }
27 
28 void intel_context_free(struct intel_context *ce)
29 {
30 	kmem_cache_free(global.slab_ce, ce);
31 }
32 
33 struct intel_context *
34 intel_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 
46 int 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 
66 unlock:
67 	mutex_unlock(&ce->pin_mutex);
68 	return err;
69 }
70 
71 static 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 
89 static 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 
96 int __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 
141 err_active:
142 	intel_context_active_release(ce);
143 out_unlock:
144 	mutex_unlock(&ce->pin_mutex);
145 out_release:
146 	i915_active_release(&ce->active);
147 	return err;
148 }
149 
150 void 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 
169 static 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 
191 err_unpin:
192 	i915_vma_unpin(vma);
193 	return err;
194 }
195 
196 static 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 
203 static 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 
217 err_pin:
218 	intel_ring_unpin(ring);
219 	return err;
220 }
221 
222 static 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
229 static 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 
247 static 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 
273 err_timeline:
274 	intel_timeline_unpin(ce->timeline);
275 err_ring:
276 	__ring_retire(ce->ring);
277 err_put:
278 	intel_context_put(ce);
279 	return err;
280 }
281 
282 void
283 intel_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 
309 void 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 
319 static void i915_global_context_shrink(void)
320 {
321 	kmem_cache_shrink(global.slab_ce);
322 }
323 
324 static void i915_global_context_exit(void)
325 {
326 	kmem_cache_destroy(global.slab_ce);
327 }
328 
329 static struct i915_global_context global = { {
330 	.shrink = i915_global_context_shrink,
331 	.exit = i915_global_context_exit,
332 } };
333 
334 int __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 
344 void intel_context_enter_engine(struct intel_context *ce)
345 {
346 	intel_engine_pm_get(ce->engine);
347 	intel_timeline_enter(ce->timeline);
348 }
349 
350 void intel_context_exit_engine(struct intel_context *ce)
351 {
352 	intel_timeline_exit(ce->timeline);
353 	intel_engine_pm_put(ce->engine);
354 }
355 
356 int 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 
383 struct 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
401