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 
17 static struct i915_global_context {
18 	struct i915_global base;
19 	struct kmem_cache *slab_ce;
20 } global;
21 
22 static struct intel_context *intel_context_alloc(void)
23 {
24 	return kmem_cache_zalloc(global.slab_ce, GFP_KERNEL);
25 }
26 
27 void intel_context_free(struct intel_context *ce)
28 {
29 	kmem_cache_free(global.slab_ce, ce);
30 }
31 
32 struct intel_context *
33 intel_context_create(struct i915_gem_context *ctx,
34 		     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, ctx, engine);
43 	return ce;
44 }
45 
46 int __intel_context_do_pin(struct intel_context *ce)
47 {
48 	int err;
49 
50 	if (mutex_lock_interruptible(&ce->pin_mutex))
51 		return -EINTR;
52 
53 	if (likely(!atomic_read(&ce->pin_count))) {
54 		intel_wakeref_t wakeref;
55 
56 		if (unlikely(!test_bit(CONTEXT_ALLOC_BIT, &ce->flags))) {
57 			err = ce->ops->alloc(ce);
58 			if (unlikely(err))
59 				goto err;
60 
61 			__set_bit(CONTEXT_ALLOC_BIT, &ce->flags);
62 		}
63 
64 		err = 0;
65 		with_intel_runtime_pm(&ce->engine->i915->runtime_pm, wakeref)
66 			err = ce->ops->pin(ce);
67 		if (err)
68 			goto err;
69 
70 		GEM_TRACE("%s context:%llx pin ring:{head:%04x, tail:%04x}\n",
71 			  ce->engine->name, ce->timeline->fence_context,
72 			  ce->ring->head, ce->ring->tail);
73 
74 		i915_gem_context_get(ce->gem_context); /* for ctx->ppgtt */
75 
76 		smp_mb__before_atomic(); /* flush pin before it is visible */
77 	}
78 
79 	atomic_inc(&ce->pin_count);
80 	GEM_BUG_ON(!intel_context_is_pinned(ce)); /* no overflow! */
81 
82 	mutex_unlock(&ce->pin_mutex);
83 	return 0;
84 
85 err:
86 	mutex_unlock(&ce->pin_mutex);
87 	return err;
88 }
89 
90 void intel_context_unpin(struct intel_context *ce)
91 {
92 	if (likely(atomic_add_unless(&ce->pin_count, -1, 1)))
93 		return;
94 
95 	/* We may be called from inside intel_context_pin() to evict another */
96 	intel_context_get(ce);
97 	mutex_lock_nested(&ce->pin_mutex, SINGLE_DEPTH_NESTING);
98 
99 	if (likely(atomic_dec_and_test(&ce->pin_count))) {
100 		GEM_TRACE("%s context:%llx retire\n",
101 			  ce->engine->name, ce->timeline->fence_context);
102 
103 		ce->ops->unpin(ce);
104 
105 		i915_gem_context_put(ce->gem_context);
106 		intel_context_active_release(ce);
107 	}
108 
109 	mutex_unlock(&ce->pin_mutex);
110 	intel_context_put(ce);
111 }
112 
113 static int __context_pin_state(struct i915_vma *vma)
114 {
115 	u64 flags;
116 	int err;
117 
118 	flags = i915_ggtt_pin_bias(vma) | PIN_OFFSET_BIAS;
119 	flags |= PIN_HIGH | PIN_GLOBAL;
120 
121 	err = i915_vma_pin(vma, 0, 0, flags);
122 	if (err)
123 		return err;
124 
125 	/*
126 	 * And mark it as a globally pinned object to let the shrinker know
127 	 * it cannot reclaim the object until we release it.
128 	 */
129 	i915_vma_make_unshrinkable(vma);
130 	vma->obj->mm.dirty = true;
131 
132 	return 0;
133 }
134 
135 static void __context_unpin_state(struct i915_vma *vma)
136 {
137 	__i915_vma_unpin(vma);
138 	i915_vma_make_shrinkable(vma);
139 }
140 
141 static void __intel_context_retire(struct i915_active *active)
142 {
143 	struct intel_context *ce = container_of(active, typeof(*ce), active);
144 
145 	GEM_TRACE("%s context:%llx retire\n",
146 		  ce->engine->name, ce->timeline->fence_context);
147 
148 	if (ce->state)
149 		__context_unpin_state(ce->state);
150 
151 	intel_timeline_unpin(ce->timeline);
152 	intel_ring_unpin(ce->ring);
153 	intel_context_put(ce);
154 }
155 
156 static int __intel_context_active(struct i915_active *active)
157 {
158 	struct intel_context *ce = container_of(active, typeof(*ce), active);
159 	int err;
160 
161 	intel_context_get(ce);
162 
163 	err = intel_ring_pin(ce->ring);
164 	if (err)
165 		goto err_put;
166 
167 	err = intel_timeline_pin(ce->timeline);
168 	if (err)
169 		goto err_ring;
170 
171 	if (!ce->state)
172 		return 0;
173 
174 	err = __context_pin_state(ce->state);
175 	if (err)
176 		goto err_timeline;
177 
178 	return 0;
179 
180 err_timeline:
181 	intel_timeline_unpin(ce->timeline);
182 err_ring:
183 	intel_ring_unpin(ce->ring);
184 err_put:
185 	intel_context_put(ce);
186 	return err;
187 }
188 
189 int intel_context_active_acquire(struct intel_context *ce)
190 {
191 	int err;
192 
193 	err = i915_active_acquire(&ce->active);
194 	if (err)
195 		return err;
196 
197 	/* Preallocate tracking nodes */
198 	if (!i915_gem_context_is_kernel(ce->gem_context)) {
199 		err = i915_active_acquire_preallocate_barrier(&ce->active,
200 							      ce->engine);
201 		if (err) {
202 			i915_active_release(&ce->active);
203 			return err;
204 		}
205 	}
206 
207 	return 0;
208 }
209 
210 void intel_context_active_release(struct intel_context *ce)
211 {
212 	/* Nodes preallocated in intel_context_active() */
213 	i915_active_acquire_barrier(&ce->active);
214 	i915_active_release(&ce->active);
215 }
216 
217 void
218 intel_context_init(struct intel_context *ce,
219 		   struct i915_gem_context *ctx,
220 		   struct intel_engine_cs *engine)
221 {
222 	GEM_BUG_ON(!engine->cops);
223 
224 	kref_init(&ce->ref);
225 
226 	ce->gem_context = ctx;
227 	ce->vm = i915_vm_get(ctx->vm ?: &engine->gt->ggtt->vm);
228 	if (ctx->timeline)
229 		ce->timeline = intel_timeline_get(ctx->timeline);
230 
231 	ce->engine = engine;
232 	ce->ops = engine->cops;
233 	ce->sseu = engine->sseu;
234 	ce->ring = __intel_context_ring_size(SZ_16K);
235 
236 	INIT_LIST_HEAD(&ce->signal_link);
237 	INIT_LIST_HEAD(&ce->signals);
238 
239 	mutex_init(&ce->pin_mutex);
240 
241 	i915_active_init(ctx->i915, &ce->active,
242 			 __intel_context_active, __intel_context_retire);
243 }
244 
245 void intel_context_fini(struct intel_context *ce)
246 {
247 	if (ce->timeline)
248 		intel_timeline_put(ce->timeline);
249 	i915_vm_put(ce->vm);
250 
251 	mutex_destroy(&ce->pin_mutex);
252 	i915_active_fini(&ce->active);
253 }
254 
255 static void i915_global_context_shrink(void)
256 {
257 	kmem_cache_shrink(global.slab_ce);
258 }
259 
260 static void i915_global_context_exit(void)
261 {
262 	kmem_cache_destroy(global.slab_ce);
263 }
264 
265 static struct i915_global_context global = { {
266 	.shrink = i915_global_context_shrink,
267 	.exit = i915_global_context_exit,
268 } };
269 
270 int __init i915_global_context_init(void)
271 {
272 	global.slab_ce = KMEM_CACHE(intel_context, SLAB_HWCACHE_ALIGN);
273 	if (!global.slab_ce)
274 		return -ENOMEM;
275 
276 	i915_global_register(&global.base);
277 	return 0;
278 }
279 
280 void intel_context_enter_engine(struct intel_context *ce)
281 {
282 	intel_engine_pm_get(ce->engine);
283 	intel_timeline_enter(ce->timeline);
284 }
285 
286 void intel_context_exit_engine(struct intel_context *ce)
287 {
288 	intel_timeline_exit(ce->timeline);
289 	intel_engine_pm_put(ce->engine);
290 }
291 
292 int intel_context_prepare_remote_request(struct intel_context *ce,
293 					 struct i915_request *rq)
294 {
295 	struct intel_timeline *tl = ce->timeline;
296 	int err;
297 
298 	/* Only suitable for use in remotely modifying this context */
299 	GEM_BUG_ON(rq->hw_context == ce);
300 
301 	if (rq->timeline != tl) { /* beware timeline sharing */
302 		err = mutex_lock_interruptible_nested(&tl->mutex,
303 						      SINGLE_DEPTH_NESTING);
304 		if (err)
305 			return err;
306 
307 		/* Queue this switch after current activity by this context. */
308 		err = i915_active_request_set(&tl->last_request, rq);
309 		mutex_unlock(&tl->mutex);
310 		if (err)
311 			return err;
312 	}
313 
314 	/*
315 	 * Guarantee context image and the timeline remains pinned until the
316 	 * modifying request is retired by setting the ce activity tracker.
317 	 *
318 	 * But we only need to take one pin on the account of it. Or in other
319 	 * words transfer the pinned ce object to tracked active request.
320 	 */
321 	GEM_BUG_ON(i915_active_is_idle(&ce->active));
322 	return i915_active_ref(&ce->active, rq->timeline, rq);
323 }
324 
325 struct i915_request *intel_context_create_request(struct intel_context *ce)
326 {
327 	struct i915_request *rq;
328 	int err;
329 
330 	err = intel_context_pin(ce);
331 	if (unlikely(err))
332 		return ERR_PTR(err);
333 
334 	rq = i915_request_create(ce);
335 	intel_context_unpin(ce);
336 
337 	return rq;
338 }
339 
340 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
341 #include "selftest_context.c"
342 #endif
343