xref: /openbmc/linux/drivers/gpu/drm/i915/gt/intel_reset.c (revision ae108c48)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2008-2018 Intel Corporation
4  */
5 
6 #include <linux/sched/mm.h>
7 #include <linux/stop_machine.h>
8 #include <linux/string_helpers.h>
9 
10 #include "display/intel_display.h"
11 #include "display/intel_overlay.h"
12 
13 #include "gem/i915_gem_context.h"
14 
15 #include "gt/intel_gt_regs.h"
16 
17 #include "i915_drv.h"
18 #include "i915_file_private.h"
19 #include "i915_gpu_error.h"
20 #include "i915_irq.h"
21 #include "intel_breadcrumbs.h"
22 #include "intel_engine_pm.h"
23 #include "intel_engine_regs.h"
24 #include "intel_gt.h"
25 #include "intel_gt_pm.h"
26 #include "intel_gt_requests.h"
27 #include "intel_mchbar_regs.h"
28 #include "intel_pci_config.h"
29 #include "intel_reset.h"
30 
31 #include "uc/intel_guc.h"
32 
33 #define RESET_MAX_RETRIES 3
34 
35 /* XXX How to handle concurrent GGTT updates using tiling registers? */
36 #define RESET_UNDER_STOP_MACHINE 0
37 
38 static void rmw_set_fw(struct intel_uncore *uncore, i915_reg_t reg, u32 set)
39 {
40 	intel_uncore_rmw_fw(uncore, reg, 0, set);
41 }
42 
43 static void rmw_clear_fw(struct intel_uncore *uncore, i915_reg_t reg, u32 clr)
44 {
45 	intel_uncore_rmw_fw(uncore, reg, clr, 0);
46 }
47 
48 static void client_mark_guilty(struct i915_gem_context *ctx, bool banned)
49 {
50 	struct drm_i915_file_private *file_priv = ctx->file_priv;
51 	unsigned long prev_hang;
52 	unsigned int score;
53 
54 	if (IS_ERR_OR_NULL(file_priv))
55 		return;
56 
57 	score = 0;
58 	if (banned)
59 		score = I915_CLIENT_SCORE_CONTEXT_BAN;
60 
61 	prev_hang = xchg(&file_priv->hang_timestamp, jiffies);
62 	if (time_before(jiffies, prev_hang + I915_CLIENT_FAST_HANG_JIFFIES))
63 		score += I915_CLIENT_SCORE_HANG_FAST;
64 
65 	if (score) {
66 		atomic_add(score, &file_priv->ban_score);
67 
68 		drm_dbg(&ctx->i915->drm,
69 			"client %s: gained %u ban score, now %u\n",
70 			ctx->name, score,
71 			atomic_read(&file_priv->ban_score));
72 	}
73 }
74 
75 static bool mark_guilty(struct i915_request *rq)
76 {
77 	struct i915_gem_context *ctx;
78 	unsigned long prev_hang;
79 	bool banned;
80 	int i;
81 
82 	if (intel_context_is_closed(rq->context))
83 		return true;
84 
85 	rcu_read_lock();
86 	ctx = rcu_dereference(rq->context->gem_context);
87 	if (ctx && !kref_get_unless_zero(&ctx->ref))
88 		ctx = NULL;
89 	rcu_read_unlock();
90 	if (!ctx)
91 		return intel_context_is_banned(rq->context);
92 
93 	atomic_inc(&ctx->guilty_count);
94 
95 	/* Cool contexts are too cool to be banned! (Used for reset testing.) */
96 	if (!i915_gem_context_is_bannable(ctx)) {
97 		banned = false;
98 		goto out;
99 	}
100 
101 	drm_notice(&ctx->i915->drm,
102 		   "%s context reset due to GPU hang\n",
103 		   ctx->name);
104 
105 	/* Record the timestamp for the last N hangs */
106 	prev_hang = ctx->hang_timestamp[0];
107 	for (i = 0; i < ARRAY_SIZE(ctx->hang_timestamp) - 1; i++)
108 		ctx->hang_timestamp[i] = ctx->hang_timestamp[i + 1];
109 	ctx->hang_timestamp[i] = jiffies;
110 
111 	/* If we have hung N+1 times in rapid succession, we ban the context! */
112 	banned = !i915_gem_context_is_recoverable(ctx);
113 	if (time_before(jiffies, prev_hang + CONTEXT_FAST_HANG_JIFFIES))
114 		banned = true;
115 	if (banned)
116 		drm_dbg(&ctx->i915->drm, "context %s: guilty %d, banned\n",
117 			ctx->name, atomic_read(&ctx->guilty_count));
118 
119 	client_mark_guilty(ctx, banned);
120 
121 out:
122 	i915_gem_context_put(ctx);
123 	return banned;
124 }
125 
126 static void mark_innocent(struct i915_request *rq)
127 {
128 	struct i915_gem_context *ctx;
129 
130 	rcu_read_lock();
131 	ctx = rcu_dereference(rq->context->gem_context);
132 	if (ctx)
133 		atomic_inc(&ctx->active_count);
134 	rcu_read_unlock();
135 }
136 
137 void __i915_request_reset(struct i915_request *rq, bool guilty)
138 {
139 	bool banned = false;
140 
141 	RQ_TRACE(rq, "guilty? %s\n", str_yes_no(guilty));
142 	GEM_BUG_ON(__i915_request_is_complete(rq));
143 
144 	rcu_read_lock(); /* protect the GEM context */
145 	if (guilty) {
146 		i915_request_set_error_once(rq, -EIO);
147 		__i915_request_skip(rq);
148 		banned = mark_guilty(rq);
149 	} else {
150 		i915_request_set_error_once(rq, -EAGAIN);
151 		mark_innocent(rq);
152 	}
153 	rcu_read_unlock();
154 
155 	if (banned)
156 		intel_context_ban(rq->context, rq);
157 }
158 
159 static bool i915_in_reset(struct pci_dev *pdev)
160 {
161 	u8 gdrst;
162 
163 	pci_read_config_byte(pdev, I915_GDRST, &gdrst);
164 	return gdrst & GRDOM_RESET_STATUS;
165 }
166 
167 static int i915_do_reset(struct intel_gt *gt,
168 			 intel_engine_mask_t engine_mask,
169 			 unsigned int retry)
170 {
171 	struct pci_dev *pdev = to_pci_dev(gt->i915->drm.dev);
172 	int err;
173 
174 	/* Assert reset for at least 20 usec, and wait for acknowledgement. */
175 	pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE);
176 	udelay(50);
177 	err = wait_for_atomic(i915_in_reset(pdev), 50);
178 
179 	/* Clear the reset request. */
180 	pci_write_config_byte(pdev, I915_GDRST, 0);
181 	udelay(50);
182 	if (!err)
183 		err = wait_for_atomic(!i915_in_reset(pdev), 50);
184 
185 	return err;
186 }
187 
188 static bool g4x_reset_complete(struct pci_dev *pdev)
189 {
190 	u8 gdrst;
191 
192 	pci_read_config_byte(pdev, I915_GDRST, &gdrst);
193 	return (gdrst & GRDOM_RESET_ENABLE) == 0;
194 }
195 
196 static int g33_do_reset(struct intel_gt *gt,
197 			intel_engine_mask_t engine_mask,
198 			unsigned int retry)
199 {
200 	struct pci_dev *pdev = to_pci_dev(gt->i915->drm.dev);
201 
202 	pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE);
203 	return wait_for_atomic(g4x_reset_complete(pdev), 50);
204 }
205 
206 static int g4x_do_reset(struct intel_gt *gt,
207 			intel_engine_mask_t engine_mask,
208 			unsigned int retry)
209 {
210 	struct pci_dev *pdev = to_pci_dev(gt->i915->drm.dev);
211 	struct intel_uncore *uncore = gt->uncore;
212 	int ret;
213 
214 	/* WaVcpClkGateDisableForMediaReset:ctg,elk */
215 	rmw_set_fw(uncore, VDECCLK_GATE_D, VCP_UNIT_CLOCK_GATE_DISABLE);
216 	intel_uncore_posting_read_fw(uncore, VDECCLK_GATE_D);
217 
218 	pci_write_config_byte(pdev, I915_GDRST,
219 			      GRDOM_MEDIA | GRDOM_RESET_ENABLE);
220 	ret =  wait_for_atomic(g4x_reset_complete(pdev), 50);
221 	if (ret) {
222 		GT_TRACE(gt, "Wait for media reset failed\n");
223 		goto out;
224 	}
225 
226 	pci_write_config_byte(pdev, I915_GDRST,
227 			      GRDOM_RENDER | GRDOM_RESET_ENABLE);
228 	ret =  wait_for_atomic(g4x_reset_complete(pdev), 50);
229 	if (ret) {
230 		GT_TRACE(gt, "Wait for render reset failed\n");
231 		goto out;
232 	}
233 
234 out:
235 	pci_write_config_byte(pdev, I915_GDRST, 0);
236 
237 	rmw_clear_fw(uncore, VDECCLK_GATE_D, VCP_UNIT_CLOCK_GATE_DISABLE);
238 	intel_uncore_posting_read_fw(uncore, VDECCLK_GATE_D);
239 
240 	return ret;
241 }
242 
243 static int ilk_do_reset(struct intel_gt *gt, intel_engine_mask_t engine_mask,
244 			unsigned int retry)
245 {
246 	struct intel_uncore *uncore = gt->uncore;
247 	int ret;
248 
249 	intel_uncore_write_fw(uncore, ILK_GDSR,
250 			      ILK_GRDOM_RENDER | ILK_GRDOM_RESET_ENABLE);
251 	ret = __intel_wait_for_register_fw(uncore, ILK_GDSR,
252 					   ILK_GRDOM_RESET_ENABLE, 0,
253 					   5000, 0,
254 					   NULL);
255 	if (ret) {
256 		GT_TRACE(gt, "Wait for render reset failed\n");
257 		goto out;
258 	}
259 
260 	intel_uncore_write_fw(uncore, ILK_GDSR,
261 			      ILK_GRDOM_MEDIA | ILK_GRDOM_RESET_ENABLE);
262 	ret = __intel_wait_for_register_fw(uncore, ILK_GDSR,
263 					   ILK_GRDOM_RESET_ENABLE, 0,
264 					   5000, 0,
265 					   NULL);
266 	if (ret) {
267 		GT_TRACE(gt, "Wait for media reset failed\n");
268 		goto out;
269 	}
270 
271 out:
272 	intel_uncore_write_fw(uncore, ILK_GDSR, 0);
273 	intel_uncore_posting_read_fw(uncore, ILK_GDSR);
274 	return ret;
275 }
276 
277 /* Reset the hardware domains (GENX_GRDOM_*) specified by mask */
278 static int gen6_hw_domain_reset(struct intel_gt *gt, u32 hw_domain_mask)
279 {
280 	struct intel_uncore *uncore = gt->uncore;
281 	int err;
282 
283 	/*
284 	 * GEN6_GDRST is not in the gt power well, no need to check
285 	 * for fifo space for the write or forcewake the chip for
286 	 * the read
287 	 */
288 	intel_uncore_write_fw(uncore, GEN6_GDRST, hw_domain_mask);
289 
290 	/* Wait for the device to ack the reset requests */
291 	err = __intel_wait_for_register_fw(uncore,
292 					   GEN6_GDRST, hw_domain_mask, 0,
293 					   500, 0,
294 					   NULL);
295 	if (err)
296 		GT_TRACE(gt,
297 			 "Wait for 0x%08x engines reset failed\n",
298 			 hw_domain_mask);
299 
300 	return err;
301 }
302 
303 static int __gen6_reset_engines(struct intel_gt *gt,
304 				intel_engine_mask_t engine_mask,
305 				unsigned int retry)
306 {
307 	struct intel_engine_cs *engine;
308 	u32 hw_mask;
309 
310 	if (engine_mask == ALL_ENGINES) {
311 		hw_mask = GEN6_GRDOM_FULL;
312 	} else {
313 		intel_engine_mask_t tmp;
314 
315 		hw_mask = 0;
316 		for_each_engine_masked(engine, gt, engine_mask, tmp) {
317 			hw_mask |= engine->reset_domain;
318 		}
319 	}
320 
321 	return gen6_hw_domain_reset(gt, hw_mask);
322 }
323 
324 static int gen6_reset_engines(struct intel_gt *gt,
325 			      intel_engine_mask_t engine_mask,
326 			      unsigned int retry)
327 {
328 	unsigned long flags;
329 	int ret;
330 
331 	spin_lock_irqsave(&gt->uncore->lock, flags);
332 	ret = __gen6_reset_engines(gt, engine_mask, retry);
333 	spin_unlock_irqrestore(&gt->uncore->lock, flags);
334 
335 	return ret;
336 }
337 
338 static struct intel_engine_cs *find_sfc_paired_vecs_engine(struct intel_engine_cs *engine)
339 {
340 	int vecs_id;
341 
342 	GEM_BUG_ON(engine->class != VIDEO_DECODE_CLASS);
343 
344 	vecs_id = _VECS((engine->instance) / 2);
345 
346 	return engine->gt->engine[vecs_id];
347 }
348 
349 struct sfc_lock_data {
350 	i915_reg_t lock_reg;
351 	i915_reg_t ack_reg;
352 	i915_reg_t usage_reg;
353 	u32 lock_bit;
354 	u32 ack_bit;
355 	u32 usage_bit;
356 	u32 reset_bit;
357 };
358 
359 static void get_sfc_forced_lock_data(struct intel_engine_cs *engine,
360 				     struct sfc_lock_data *sfc_lock)
361 {
362 	switch (engine->class) {
363 	default:
364 		MISSING_CASE(engine->class);
365 		fallthrough;
366 	case VIDEO_DECODE_CLASS:
367 		sfc_lock->lock_reg = GEN11_VCS_SFC_FORCED_LOCK(engine->mmio_base);
368 		sfc_lock->lock_bit = GEN11_VCS_SFC_FORCED_LOCK_BIT;
369 
370 		sfc_lock->ack_reg = GEN11_VCS_SFC_LOCK_STATUS(engine->mmio_base);
371 		sfc_lock->ack_bit  = GEN11_VCS_SFC_LOCK_ACK_BIT;
372 
373 		sfc_lock->usage_reg = GEN11_VCS_SFC_LOCK_STATUS(engine->mmio_base);
374 		sfc_lock->usage_bit = GEN11_VCS_SFC_USAGE_BIT;
375 		sfc_lock->reset_bit = GEN11_VCS_SFC_RESET_BIT(engine->instance);
376 
377 		break;
378 	case VIDEO_ENHANCEMENT_CLASS:
379 		sfc_lock->lock_reg = GEN11_VECS_SFC_FORCED_LOCK(engine->mmio_base);
380 		sfc_lock->lock_bit = GEN11_VECS_SFC_FORCED_LOCK_BIT;
381 
382 		sfc_lock->ack_reg = GEN11_VECS_SFC_LOCK_ACK(engine->mmio_base);
383 		sfc_lock->ack_bit  = GEN11_VECS_SFC_LOCK_ACK_BIT;
384 
385 		sfc_lock->usage_reg = GEN11_VECS_SFC_USAGE(engine->mmio_base);
386 		sfc_lock->usage_bit = GEN11_VECS_SFC_USAGE_BIT;
387 		sfc_lock->reset_bit = GEN11_VECS_SFC_RESET_BIT(engine->instance);
388 
389 		break;
390 	}
391 }
392 
393 static int gen11_lock_sfc(struct intel_engine_cs *engine,
394 			  u32 *reset_mask,
395 			  u32 *unlock_mask)
396 {
397 	struct intel_uncore *uncore = engine->uncore;
398 	u8 vdbox_sfc_access = engine->gt->info.vdbox_sfc_access;
399 	struct sfc_lock_data sfc_lock;
400 	bool lock_obtained, lock_to_other = false;
401 	int ret;
402 
403 	switch (engine->class) {
404 	case VIDEO_DECODE_CLASS:
405 		if ((BIT(engine->instance) & vdbox_sfc_access) == 0)
406 			return 0;
407 
408 		fallthrough;
409 	case VIDEO_ENHANCEMENT_CLASS:
410 		get_sfc_forced_lock_data(engine, &sfc_lock);
411 
412 		break;
413 	default:
414 		return 0;
415 	}
416 
417 	if (!(intel_uncore_read_fw(uncore, sfc_lock.usage_reg) & sfc_lock.usage_bit)) {
418 		struct intel_engine_cs *paired_vecs;
419 
420 		if (engine->class != VIDEO_DECODE_CLASS ||
421 		    GRAPHICS_VER(engine->i915) != 12)
422 			return 0;
423 
424 		/*
425 		 * Wa_14010733141
426 		 *
427 		 * If the VCS-MFX isn't using the SFC, we also need to check
428 		 * whether VCS-HCP is using it.  If so, we need to issue a *VE*
429 		 * forced lock on the VE engine that shares the same SFC.
430 		 */
431 		if (!(intel_uncore_read_fw(uncore,
432 					   GEN12_HCP_SFC_LOCK_STATUS(engine->mmio_base)) &
433 		      GEN12_HCP_SFC_USAGE_BIT))
434 			return 0;
435 
436 		paired_vecs = find_sfc_paired_vecs_engine(engine);
437 		get_sfc_forced_lock_data(paired_vecs, &sfc_lock);
438 		lock_to_other = true;
439 		*unlock_mask |= paired_vecs->mask;
440 	} else {
441 		*unlock_mask |= engine->mask;
442 	}
443 
444 	/*
445 	 * If the engine is using an SFC, tell the engine that a software reset
446 	 * is going to happen. The engine will then try to force lock the SFC.
447 	 * If SFC ends up being locked to the engine we want to reset, we have
448 	 * to reset it as well (we will unlock it once the reset sequence is
449 	 * completed).
450 	 */
451 	rmw_set_fw(uncore, sfc_lock.lock_reg, sfc_lock.lock_bit);
452 
453 	ret = __intel_wait_for_register_fw(uncore,
454 					   sfc_lock.ack_reg,
455 					   sfc_lock.ack_bit,
456 					   sfc_lock.ack_bit,
457 					   1000, 0, NULL);
458 
459 	/*
460 	 * Was the SFC released while we were trying to lock it?
461 	 *
462 	 * We should reset both the engine and the SFC if:
463 	 *  - We were locking the SFC to this engine and the lock succeeded
464 	 *       OR
465 	 *  - We were locking the SFC to a different engine (Wa_14010733141)
466 	 *    but the SFC was released before the lock was obtained.
467 	 *
468 	 * Otherwise we need only reset the engine by itself and we can
469 	 * leave the SFC alone.
470 	 */
471 	lock_obtained = (intel_uncore_read_fw(uncore, sfc_lock.usage_reg) &
472 			sfc_lock.usage_bit) != 0;
473 	if (lock_obtained == lock_to_other)
474 		return 0;
475 
476 	if (ret) {
477 		ENGINE_TRACE(engine, "Wait for SFC forced lock ack failed\n");
478 		return ret;
479 	}
480 
481 	*reset_mask |= sfc_lock.reset_bit;
482 	return 0;
483 }
484 
485 static void gen11_unlock_sfc(struct intel_engine_cs *engine)
486 {
487 	struct intel_uncore *uncore = engine->uncore;
488 	u8 vdbox_sfc_access = engine->gt->info.vdbox_sfc_access;
489 	struct sfc_lock_data sfc_lock = {};
490 
491 	if (engine->class != VIDEO_DECODE_CLASS &&
492 	    engine->class != VIDEO_ENHANCEMENT_CLASS)
493 		return;
494 
495 	if (engine->class == VIDEO_DECODE_CLASS &&
496 	    (BIT(engine->instance) & vdbox_sfc_access) == 0)
497 		return;
498 
499 	get_sfc_forced_lock_data(engine, &sfc_lock);
500 
501 	rmw_clear_fw(uncore, sfc_lock.lock_reg, sfc_lock.lock_bit);
502 }
503 
504 static int __gen11_reset_engines(struct intel_gt *gt,
505 				 intel_engine_mask_t engine_mask,
506 				 unsigned int retry)
507 {
508 	struct intel_engine_cs *engine;
509 	intel_engine_mask_t tmp;
510 	u32 reset_mask, unlock_mask = 0;
511 	int ret;
512 
513 	if (engine_mask == ALL_ENGINES) {
514 		reset_mask = GEN11_GRDOM_FULL;
515 	} else {
516 		reset_mask = 0;
517 		for_each_engine_masked(engine, gt, engine_mask, tmp) {
518 			reset_mask |= engine->reset_domain;
519 			ret = gen11_lock_sfc(engine, &reset_mask, &unlock_mask);
520 			if (ret)
521 				goto sfc_unlock;
522 		}
523 	}
524 
525 	ret = gen6_hw_domain_reset(gt, reset_mask);
526 
527 sfc_unlock:
528 	/*
529 	 * We unlock the SFC based on the lock status and not the result of
530 	 * gen11_lock_sfc to make sure that we clean properly if something
531 	 * wrong happened during the lock (e.g. lock acquired after timeout
532 	 * expiration).
533 	 *
534 	 * Due to Wa_14010733141, we may have locked an SFC to an engine that
535 	 * wasn't being reset.  So instead of calling gen11_unlock_sfc()
536 	 * on engine_mask, we instead call it on the mask of engines that our
537 	 * gen11_lock_sfc() calls told us actually had locks attempted.
538 	 */
539 	for_each_engine_masked(engine, gt, unlock_mask, tmp)
540 		gen11_unlock_sfc(engine);
541 
542 	return ret;
543 }
544 
545 static int gen8_engine_reset_prepare(struct intel_engine_cs *engine)
546 {
547 	struct intel_uncore *uncore = engine->uncore;
548 	const i915_reg_t reg = RING_RESET_CTL(engine->mmio_base);
549 	u32 request, mask, ack;
550 	int ret;
551 
552 	if (I915_SELFTEST_ONLY(should_fail(&engine->reset_timeout, 1)))
553 		return -ETIMEDOUT;
554 
555 	ack = intel_uncore_read_fw(uncore, reg);
556 	if (ack & RESET_CTL_CAT_ERROR) {
557 		/*
558 		 * For catastrophic errors, ready-for-reset sequence
559 		 * needs to be bypassed: HAS#396813
560 		 */
561 		request = RESET_CTL_CAT_ERROR;
562 		mask = RESET_CTL_CAT_ERROR;
563 
564 		/* Catastrophic errors need to be cleared by HW */
565 		ack = 0;
566 	} else if (!(ack & RESET_CTL_READY_TO_RESET)) {
567 		request = RESET_CTL_REQUEST_RESET;
568 		mask = RESET_CTL_READY_TO_RESET;
569 		ack = RESET_CTL_READY_TO_RESET;
570 	} else {
571 		return 0;
572 	}
573 
574 	intel_uncore_write_fw(uncore, reg, _MASKED_BIT_ENABLE(request));
575 	ret = __intel_wait_for_register_fw(uncore, reg, mask, ack,
576 					   700, 0, NULL);
577 	if (ret)
578 		drm_err(&engine->i915->drm,
579 			"%s reset request timed out: {request: %08x, RESET_CTL: %08x}\n",
580 			engine->name, request,
581 			intel_uncore_read_fw(uncore, reg));
582 
583 	return ret;
584 }
585 
586 static void gen8_engine_reset_cancel(struct intel_engine_cs *engine)
587 {
588 	intel_uncore_write_fw(engine->uncore,
589 			      RING_RESET_CTL(engine->mmio_base),
590 			      _MASKED_BIT_DISABLE(RESET_CTL_REQUEST_RESET));
591 }
592 
593 static int gen8_reset_engines(struct intel_gt *gt,
594 			      intel_engine_mask_t engine_mask,
595 			      unsigned int retry)
596 {
597 	struct intel_engine_cs *engine;
598 	const bool reset_non_ready = retry >= 1;
599 	intel_engine_mask_t tmp;
600 	unsigned long flags;
601 	int ret;
602 
603 	spin_lock_irqsave(&gt->uncore->lock, flags);
604 
605 	for_each_engine_masked(engine, gt, engine_mask, tmp) {
606 		ret = gen8_engine_reset_prepare(engine);
607 		if (ret && !reset_non_ready)
608 			goto skip_reset;
609 
610 		/*
611 		 * If this is not the first failed attempt to prepare,
612 		 * we decide to proceed anyway.
613 		 *
614 		 * By doing so we risk context corruption and with
615 		 * some gens (kbl), possible system hang if reset
616 		 * happens during active bb execution.
617 		 *
618 		 * We rather take context corruption instead of
619 		 * failed reset with a wedged driver/gpu. And
620 		 * active bb execution case should be covered by
621 		 * stop_engines() we have before the reset.
622 		 */
623 	}
624 
625 	/*
626 	 * Wa_22011100796:dg2, whenever Full soft reset is required,
627 	 * reset all individual engines firstly, and then do a full soft reset.
628 	 *
629 	 * This is best effort, so ignore any error from the initial reset.
630 	 */
631 	if (IS_DG2(gt->i915) && engine_mask == ALL_ENGINES)
632 		__gen11_reset_engines(gt, gt->info.engine_mask, 0);
633 
634 	if (GRAPHICS_VER(gt->i915) >= 11)
635 		ret = __gen11_reset_engines(gt, engine_mask, retry);
636 	else
637 		ret = __gen6_reset_engines(gt, engine_mask, retry);
638 
639 skip_reset:
640 	for_each_engine_masked(engine, gt, engine_mask, tmp)
641 		gen8_engine_reset_cancel(engine);
642 
643 	spin_unlock_irqrestore(&gt->uncore->lock, flags);
644 
645 	return ret;
646 }
647 
648 static int mock_reset(struct intel_gt *gt,
649 		      intel_engine_mask_t mask,
650 		      unsigned int retry)
651 {
652 	return 0;
653 }
654 
655 typedef int (*reset_func)(struct intel_gt *,
656 			  intel_engine_mask_t engine_mask,
657 			  unsigned int retry);
658 
659 static reset_func intel_get_gpu_reset(const struct intel_gt *gt)
660 {
661 	struct drm_i915_private *i915 = gt->i915;
662 
663 	if (is_mock_gt(gt))
664 		return mock_reset;
665 	else if (GRAPHICS_VER(i915) >= 8)
666 		return gen8_reset_engines;
667 	else if (GRAPHICS_VER(i915) >= 6)
668 		return gen6_reset_engines;
669 	else if (GRAPHICS_VER(i915) >= 5)
670 		return ilk_do_reset;
671 	else if (IS_G4X(i915))
672 		return g4x_do_reset;
673 	else if (IS_G33(i915) || IS_PINEVIEW(i915))
674 		return g33_do_reset;
675 	else if (GRAPHICS_VER(i915) >= 3)
676 		return i915_do_reset;
677 	else
678 		return NULL;
679 }
680 
681 int __intel_gt_reset(struct intel_gt *gt, intel_engine_mask_t engine_mask)
682 {
683 	const int retries = engine_mask == ALL_ENGINES ? RESET_MAX_RETRIES : 1;
684 	reset_func reset;
685 	int ret = -ETIMEDOUT;
686 	int retry;
687 
688 	reset = intel_get_gpu_reset(gt);
689 	if (!reset)
690 		return -ENODEV;
691 
692 	/*
693 	 * If the power well sleeps during the reset, the reset
694 	 * request may be dropped and never completes (causing -EIO).
695 	 */
696 	intel_uncore_forcewake_get(gt->uncore, FORCEWAKE_ALL);
697 	for (retry = 0; ret == -ETIMEDOUT && retry < retries; retry++) {
698 		GT_TRACE(gt, "engine_mask=%x\n", engine_mask);
699 		preempt_disable();
700 		ret = reset(gt, engine_mask, retry);
701 		preempt_enable();
702 	}
703 	intel_uncore_forcewake_put(gt->uncore, FORCEWAKE_ALL);
704 
705 	return ret;
706 }
707 
708 bool intel_has_gpu_reset(const struct intel_gt *gt)
709 {
710 	if (!gt->i915->params.reset)
711 		return NULL;
712 
713 	return intel_get_gpu_reset(gt);
714 }
715 
716 bool intel_has_reset_engine(const struct intel_gt *gt)
717 {
718 	if (gt->i915->params.reset < 2)
719 		return false;
720 
721 	return INTEL_INFO(gt->i915)->has_reset_engine;
722 }
723 
724 int intel_reset_guc(struct intel_gt *gt)
725 {
726 	u32 guc_domain =
727 		GRAPHICS_VER(gt->i915) >= 11 ? GEN11_GRDOM_GUC : GEN9_GRDOM_GUC;
728 	int ret;
729 
730 	GEM_BUG_ON(!HAS_GT_UC(gt->i915));
731 
732 	intel_uncore_forcewake_get(gt->uncore, FORCEWAKE_ALL);
733 	ret = gen6_hw_domain_reset(gt, guc_domain);
734 	intel_uncore_forcewake_put(gt->uncore, FORCEWAKE_ALL);
735 
736 	return ret;
737 }
738 
739 /*
740  * Ensure irq handler finishes, and not run again.
741  * Also return the active request so that we only search for it once.
742  */
743 static void reset_prepare_engine(struct intel_engine_cs *engine)
744 {
745 	/*
746 	 * During the reset sequence, we must prevent the engine from
747 	 * entering RC6. As the context state is undefined until we restart
748 	 * the engine, if it does enter RC6 during the reset, the state
749 	 * written to the powercontext is undefined and so we may lose
750 	 * GPU state upon resume, i.e. fail to restart after a reset.
751 	 */
752 	intel_uncore_forcewake_get(engine->uncore, FORCEWAKE_ALL);
753 	if (engine->reset.prepare)
754 		engine->reset.prepare(engine);
755 }
756 
757 static void revoke_mmaps(struct intel_gt *gt)
758 {
759 	int i;
760 
761 	for (i = 0; i < gt->ggtt->num_fences; i++) {
762 		struct drm_vma_offset_node *node;
763 		struct i915_vma *vma;
764 		u64 vma_offset;
765 
766 		vma = READ_ONCE(gt->ggtt->fence_regs[i].vma);
767 		if (!vma)
768 			continue;
769 
770 		if (!i915_vma_has_userfault(vma))
771 			continue;
772 
773 		GEM_BUG_ON(vma->fence != &gt->ggtt->fence_regs[i]);
774 
775 		if (!vma->mmo)
776 			continue;
777 
778 		node = &vma->mmo->vma_node;
779 		vma_offset = vma->gtt_view.partial.offset << PAGE_SHIFT;
780 
781 		unmap_mapping_range(gt->i915->drm.anon_inode->i_mapping,
782 				    drm_vma_node_offset_addr(node) + vma_offset,
783 				    vma->size,
784 				    1);
785 	}
786 }
787 
788 static intel_engine_mask_t reset_prepare(struct intel_gt *gt)
789 {
790 	struct intel_engine_cs *engine;
791 	intel_engine_mask_t awake = 0;
792 	enum intel_engine_id id;
793 
794 	/* For GuC mode, ensure submission is disabled before stopping ring */
795 	intel_uc_reset_prepare(&gt->uc);
796 
797 	for_each_engine(engine, gt, id) {
798 		if (intel_engine_pm_get_if_awake(engine))
799 			awake |= engine->mask;
800 		reset_prepare_engine(engine);
801 	}
802 
803 	return awake;
804 }
805 
806 static void gt_revoke(struct intel_gt *gt)
807 {
808 	revoke_mmaps(gt);
809 }
810 
811 static int gt_reset(struct intel_gt *gt, intel_engine_mask_t stalled_mask)
812 {
813 	struct intel_engine_cs *engine;
814 	enum intel_engine_id id;
815 	int err;
816 
817 	/*
818 	 * Everything depends on having the GTT running, so we need to start
819 	 * there.
820 	 */
821 	err = i915_ggtt_enable_hw(gt->i915);
822 	if (err)
823 		return err;
824 
825 	local_bh_disable();
826 	for_each_engine(engine, gt, id)
827 		__intel_engine_reset(engine, stalled_mask & engine->mask);
828 	local_bh_enable();
829 
830 	intel_uc_reset(&gt->uc, ALL_ENGINES);
831 
832 	intel_ggtt_restore_fences(gt->ggtt);
833 
834 	return err;
835 }
836 
837 static void reset_finish_engine(struct intel_engine_cs *engine)
838 {
839 	if (engine->reset.finish)
840 		engine->reset.finish(engine);
841 	intel_uncore_forcewake_put(engine->uncore, FORCEWAKE_ALL);
842 
843 	intel_engine_signal_breadcrumbs(engine);
844 }
845 
846 static void reset_finish(struct intel_gt *gt, intel_engine_mask_t awake)
847 {
848 	struct intel_engine_cs *engine;
849 	enum intel_engine_id id;
850 
851 	for_each_engine(engine, gt, id) {
852 		reset_finish_engine(engine);
853 		if (awake & engine->mask)
854 			intel_engine_pm_put(engine);
855 	}
856 
857 	intel_uc_reset_finish(&gt->uc);
858 }
859 
860 static void nop_submit_request(struct i915_request *request)
861 {
862 	RQ_TRACE(request, "-EIO\n");
863 
864 	request = i915_request_mark_eio(request);
865 	if (request) {
866 		i915_request_submit(request);
867 		intel_engine_signal_breadcrumbs(request->engine);
868 
869 		i915_request_put(request);
870 	}
871 }
872 
873 static void __intel_gt_set_wedged(struct intel_gt *gt)
874 {
875 	struct intel_engine_cs *engine;
876 	intel_engine_mask_t awake;
877 	enum intel_engine_id id;
878 
879 	if (test_bit(I915_WEDGED, &gt->reset.flags))
880 		return;
881 
882 	GT_TRACE(gt, "start\n");
883 
884 	/*
885 	 * First, stop submission to hw, but do not yet complete requests by
886 	 * rolling the global seqno forward (since this would complete requests
887 	 * for which we haven't set the fence error to EIO yet).
888 	 */
889 	awake = reset_prepare(gt);
890 
891 	/* Even if the GPU reset fails, it should still stop the engines */
892 	if (!INTEL_INFO(gt->i915)->gpu_reset_clobbers_display)
893 		__intel_gt_reset(gt, ALL_ENGINES);
894 
895 	for_each_engine(engine, gt, id)
896 		engine->submit_request = nop_submit_request;
897 
898 	/*
899 	 * Make sure no request can slip through without getting completed by
900 	 * either this call here to intel_engine_write_global_seqno, or the one
901 	 * in nop_submit_request.
902 	 */
903 	synchronize_rcu_expedited();
904 	set_bit(I915_WEDGED, &gt->reset.flags);
905 
906 	/* Mark all executing requests as skipped */
907 	local_bh_disable();
908 	for_each_engine(engine, gt, id)
909 		if (engine->reset.cancel)
910 			engine->reset.cancel(engine);
911 	intel_uc_cancel_requests(&gt->uc);
912 	local_bh_enable();
913 
914 	reset_finish(gt, awake);
915 
916 	GT_TRACE(gt, "end\n");
917 }
918 
919 void intel_gt_set_wedged(struct intel_gt *gt)
920 {
921 	intel_wakeref_t wakeref;
922 
923 	if (test_bit(I915_WEDGED, &gt->reset.flags))
924 		return;
925 
926 	wakeref = intel_runtime_pm_get(gt->uncore->rpm);
927 	mutex_lock(&gt->reset.mutex);
928 
929 	if (GEM_SHOW_DEBUG()) {
930 		struct drm_printer p = drm_debug_printer(__func__);
931 		struct intel_engine_cs *engine;
932 		enum intel_engine_id id;
933 
934 		drm_printf(&p, "called from %pS\n", (void *)_RET_IP_);
935 		for_each_engine(engine, gt, id) {
936 			if (intel_engine_is_idle(engine))
937 				continue;
938 
939 			intel_engine_dump(engine, &p, "%s\n", engine->name);
940 		}
941 	}
942 
943 	__intel_gt_set_wedged(gt);
944 
945 	mutex_unlock(&gt->reset.mutex);
946 	intel_runtime_pm_put(gt->uncore->rpm, wakeref);
947 }
948 
949 static bool __intel_gt_unset_wedged(struct intel_gt *gt)
950 {
951 	struct intel_gt_timelines *timelines = &gt->timelines;
952 	struct intel_timeline *tl;
953 	bool ok;
954 
955 	if (!test_bit(I915_WEDGED, &gt->reset.flags))
956 		return true;
957 
958 	/* Never fully initialised, recovery impossible */
959 	if (intel_gt_has_unrecoverable_error(gt))
960 		return false;
961 
962 	GT_TRACE(gt, "start\n");
963 
964 	/*
965 	 * Before unwedging, make sure that all pending operations
966 	 * are flushed and errored out - we may have requests waiting upon
967 	 * third party fences. We marked all inflight requests as EIO, and
968 	 * every execbuf since returned EIO, for consistency we want all
969 	 * the currently pending requests to also be marked as EIO, which
970 	 * is done inside our nop_submit_request - and so we must wait.
971 	 *
972 	 * No more can be submitted until we reset the wedged bit.
973 	 */
974 	spin_lock(&timelines->lock);
975 	list_for_each_entry(tl, &timelines->active_list, link) {
976 		struct dma_fence *fence;
977 
978 		fence = i915_active_fence_get(&tl->last_request);
979 		if (!fence)
980 			continue;
981 
982 		spin_unlock(&timelines->lock);
983 
984 		/*
985 		 * All internal dependencies (i915_requests) will have
986 		 * been flushed by the set-wedge, but we may be stuck waiting
987 		 * for external fences. These should all be capped to 10s
988 		 * (I915_FENCE_TIMEOUT) so this wait should not be unbounded
989 		 * in the worst case.
990 		 */
991 		dma_fence_default_wait(fence, false, MAX_SCHEDULE_TIMEOUT);
992 		dma_fence_put(fence);
993 
994 		/* Restart iteration after droping lock */
995 		spin_lock(&timelines->lock);
996 		tl = list_entry(&timelines->active_list, typeof(*tl), link);
997 	}
998 	spin_unlock(&timelines->lock);
999 
1000 	/* We must reset pending GPU events before restoring our submission */
1001 	ok = !HAS_EXECLISTS(gt->i915); /* XXX better agnosticism desired */
1002 	if (!INTEL_INFO(gt->i915)->gpu_reset_clobbers_display)
1003 		ok = __intel_gt_reset(gt, ALL_ENGINES) == 0;
1004 	if (!ok) {
1005 		/*
1006 		 * Warn CI about the unrecoverable wedged condition.
1007 		 * Time for a reboot.
1008 		 */
1009 		add_taint_for_CI(gt->i915, TAINT_WARN);
1010 		return false;
1011 	}
1012 
1013 	/*
1014 	 * Undo nop_submit_request. We prevent all new i915 requests from
1015 	 * being queued (by disallowing execbuf whilst wedged) so having
1016 	 * waited for all active requests above, we know the system is idle
1017 	 * and do not have to worry about a thread being inside
1018 	 * engine->submit_request() as we swap over. So unlike installing
1019 	 * the nop_submit_request on reset, we can do this from normal
1020 	 * context and do not require stop_machine().
1021 	 */
1022 	intel_engines_reset_default_submission(gt);
1023 
1024 	GT_TRACE(gt, "end\n");
1025 
1026 	smp_mb__before_atomic(); /* complete takeover before enabling execbuf */
1027 	clear_bit(I915_WEDGED, &gt->reset.flags);
1028 
1029 	return true;
1030 }
1031 
1032 bool intel_gt_unset_wedged(struct intel_gt *gt)
1033 {
1034 	bool result;
1035 
1036 	mutex_lock(&gt->reset.mutex);
1037 	result = __intel_gt_unset_wedged(gt);
1038 	mutex_unlock(&gt->reset.mutex);
1039 
1040 	return result;
1041 }
1042 
1043 static int do_reset(struct intel_gt *gt, intel_engine_mask_t stalled_mask)
1044 {
1045 	int err, i;
1046 
1047 	err = __intel_gt_reset(gt, ALL_ENGINES);
1048 	for (i = 0; err && i < RESET_MAX_RETRIES; i++) {
1049 		msleep(10 * (i + 1));
1050 		err = __intel_gt_reset(gt, ALL_ENGINES);
1051 	}
1052 	if (err)
1053 		return err;
1054 
1055 	return gt_reset(gt, stalled_mask);
1056 }
1057 
1058 static int resume(struct intel_gt *gt)
1059 {
1060 	struct intel_engine_cs *engine;
1061 	enum intel_engine_id id;
1062 	int ret;
1063 
1064 	for_each_engine(engine, gt, id) {
1065 		ret = intel_engine_resume(engine);
1066 		if (ret)
1067 			return ret;
1068 	}
1069 
1070 	return 0;
1071 }
1072 
1073 /**
1074  * intel_gt_reset - reset chip after a hang
1075  * @gt: #intel_gt to reset
1076  * @stalled_mask: mask of the stalled engines with the guilty requests
1077  * @reason: user error message for why we are resetting
1078  *
1079  * Reset the chip.  Useful if a hang is detected. Marks the device as wedged
1080  * on failure.
1081  *
1082  * Procedure is fairly simple:
1083  *   - reset the chip using the reset reg
1084  *   - re-init context state
1085  *   - re-init hardware status page
1086  *   - re-init ring buffer
1087  *   - re-init interrupt state
1088  *   - re-init display
1089  */
1090 void intel_gt_reset(struct intel_gt *gt,
1091 		    intel_engine_mask_t stalled_mask,
1092 		    const char *reason)
1093 {
1094 	intel_engine_mask_t awake;
1095 	int ret;
1096 
1097 	GT_TRACE(gt, "flags=%lx\n", gt->reset.flags);
1098 
1099 	might_sleep();
1100 	GEM_BUG_ON(!test_bit(I915_RESET_BACKOFF, &gt->reset.flags));
1101 
1102 	/*
1103 	 * FIXME: Revoking cpu mmap ptes cannot be done from a dma_fence
1104 	 * critical section like gpu reset.
1105 	 */
1106 	gt_revoke(gt);
1107 
1108 	mutex_lock(&gt->reset.mutex);
1109 
1110 	/* Clear any previous failed attempts at recovery. Time to try again. */
1111 	if (!__intel_gt_unset_wedged(gt))
1112 		goto unlock;
1113 
1114 	if (reason)
1115 		drm_notice(&gt->i915->drm,
1116 			   "Resetting chip for %s\n", reason);
1117 	atomic_inc(&gt->i915->gpu_error.reset_count);
1118 
1119 	awake = reset_prepare(gt);
1120 
1121 	if (!intel_has_gpu_reset(gt)) {
1122 		if (gt->i915->params.reset)
1123 			drm_err(&gt->i915->drm, "GPU reset not supported\n");
1124 		else
1125 			drm_dbg(&gt->i915->drm, "GPU reset disabled\n");
1126 		goto error;
1127 	}
1128 
1129 	if (INTEL_INFO(gt->i915)->gpu_reset_clobbers_display)
1130 		intel_runtime_pm_disable_interrupts(gt->i915);
1131 
1132 	if (do_reset(gt, stalled_mask)) {
1133 		drm_err(&gt->i915->drm, "Failed to reset chip\n");
1134 		goto taint;
1135 	}
1136 
1137 	if (INTEL_INFO(gt->i915)->gpu_reset_clobbers_display)
1138 		intel_runtime_pm_enable_interrupts(gt->i915);
1139 
1140 	intel_overlay_reset(gt->i915);
1141 
1142 	/*
1143 	 * Next we need to restore the context, but we don't use those
1144 	 * yet either...
1145 	 *
1146 	 * Ring buffer needs to be re-initialized in the KMS case, or if X
1147 	 * was running at the time of the reset (i.e. we weren't VT
1148 	 * switched away).
1149 	 */
1150 	ret = intel_gt_init_hw(gt);
1151 	if (ret) {
1152 		drm_err(&gt->i915->drm,
1153 			"Failed to initialise HW following reset (%d)\n",
1154 			ret);
1155 		goto taint;
1156 	}
1157 
1158 	ret = resume(gt);
1159 	if (ret)
1160 		goto taint;
1161 
1162 finish:
1163 	reset_finish(gt, awake);
1164 unlock:
1165 	mutex_unlock(&gt->reset.mutex);
1166 	return;
1167 
1168 taint:
1169 	/*
1170 	 * History tells us that if we cannot reset the GPU now, we
1171 	 * never will. This then impacts everything that is run
1172 	 * subsequently. On failing the reset, we mark the driver
1173 	 * as wedged, preventing further execution on the GPU.
1174 	 * We also want to go one step further and add a taint to the
1175 	 * kernel so that any subsequent faults can be traced back to
1176 	 * this failure. This is important for CI, where if the
1177 	 * GPU/driver fails we would like to reboot and restart testing
1178 	 * rather than continue on into oblivion. For everyone else,
1179 	 * the system should still plod along, but they have been warned!
1180 	 */
1181 	add_taint_for_CI(gt->i915, TAINT_WARN);
1182 error:
1183 	__intel_gt_set_wedged(gt);
1184 	goto finish;
1185 }
1186 
1187 static int intel_gt_reset_engine(struct intel_engine_cs *engine)
1188 {
1189 	return __intel_gt_reset(engine->gt, engine->mask);
1190 }
1191 
1192 int __intel_engine_reset_bh(struct intel_engine_cs *engine, const char *msg)
1193 {
1194 	struct intel_gt *gt = engine->gt;
1195 	int ret;
1196 
1197 	ENGINE_TRACE(engine, "flags=%lx\n", gt->reset.flags);
1198 	GEM_BUG_ON(!test_bit(I915_RESET_ENGINE + engine->id, &gt->reset.flags));
1199 
1200 	if (intel_engine_uses_guc(engine))
1201 		return -ENODEV;
1202 
1203 	if (!intel_engine_pm_get_if_awake(engine))
1204 		return 0;
1205 
1206 	reset_prepare_engine(engine);
1207 
1208 	if (msg)
1209 		drm_notice(&engine->i915->drm,
1210 			   "Resetting %s for %s\n", engine->name, msg);
1211 	atomic_inc(&engine->i915->gpu_error.reset_engine_count[engine->uabi_class]);
1212 
1213 	ret = intel_gt_reset_engine(engine);
1214 	if (ret) {
1215 		/* If we fail here, we expect to fallback to a global reset */
1216 		ENGINE_TRACE(engine, "Failed to reset %s, err: %d\n", engine->name, ret);
1217 		goto out;
1218 	}
1219 
1220 	/*
1221 	 * The request that caused the hang is stuck on elsp, we know the
1222 	 * active request and can drop it, adjust head to skip the offending
1223 	 * request to resume executing remaining requests in the queue.
1224 	 */
1225 	__intel_engine_reset(engine, true);
1226 
1227 	/*
1228 	 * The engine and its registers (and workarounds in case of render)
1229 	 * have been reset to their default values. Follow the init_ring
1230 	 * process to program RING_MODE, HWSP and re-enable submission.
1231 	 */
1232 	ret = intel_engine_resume(engine);
1233 
1234 out:
1235 	intel_engine_cancel_stop_cs(engine);
1236 	reset_finish_engine(engine);
1237 	intel_engine_pm_put_async(engine);
1238 	return ret;
1239 }
1240 
1241 /**
1242  * intel_engine_reset - reset GPU engine to recover from a hang
1243  * @engine: engine to reset
1244  * @msg: reason for GPU reset; or NULL for no drm_notice()
1245  *
1246  * Reset a specific GPU engine. Useful if a hang is detected.
1247  * Returns zero on successful reset or otherwise an error code.
1248  *
1249  * Procedure is:
1250  *  - identifies the request that caused the hang and it is dropped
1251  *  - reset engine (which will force the engine to idle)
1252  *  - re-init/configure engine
1253  */
1254 int intel_engine_reset(struct intel_engine_cs *engine, const char *msg)
1255 {
1256 	int err;
1257 
1258 	local_bh_disable();
1259 	err = __intel_engine_reset_bh(engine, msg);
1260 	local_bh_enable();
1261 
1262 	return err;
1263 }
1264 
1265 static void intel_gt_reset_global(struct intel_gt *gt,
1266 				  u32 engine_mask,
1267 				  const char *reason)
1268 {
1269 	struct kobject *kobj = &gt->i915->drm.primary->kdev->kobj;
1270 	char *error_event[] = { I915_ERROR_UEVENT "=1", NULL };
1271 	char *reset_event[] = { I915_RESET_UEVENT "=1", NULL };
1272 	char *reset_done_event[] = { I915_ERROR_UEVENT "=0", NULL };
1273 	struct intel_wedge_me w;
1274 
1275 	kobject_uevent_env(kobj, KOBJ_CHANGE, error_event);
1276 
1277 	GT_TRACE(gt, "resetting chip, engines=%x\n", engine_mask);
1278 	kobject_uevent_env(kobj, KOBJ_CHANGE, reset_event);
1279 
1280 	/* Use a watchdog to ensure that our reset completes */
1281 	intel_wedge_on_timeout(&w, gt, 5 * HZ) {
1282 		intel_display_prepare_reset(gt->i915);
1283 
1284 		intel_gt_reset(gt, engine_mask, reason);
1285 
1286 		intel_display_finish_reset(gt->i915);
1287 	}
1288 
1289 	if (!test_bit(I915_WEDGED, &gt->reset.flags))
1290 		kobject_uevent_env(kobj, KOBJ_CHANGE, reset_done_event);
1291 }
1292 
1293 /**
1294  * intel_gt_handle_error - handle a gpu error
1295  * @gt: the intel_gt
1296  * @engine_mask: mask representing engines that are hung
1297  * @flags: control flags
1298  * @fmt: Error message format string
1299  *
1300  * Do some basic checking of register state at error time and
1301  * dump it to the syslog.  Also call i915_capture_error_state() to make
1302  * sure we get a record and make it available in debugfs.  Fire a uevent
1303  * so userspace knows something bad happened (should trigger collection
1304  * of a ring dump etc.).
1305  */
1306 void intel_gt_handle_error(struct intel_gt *gt,
1307 			   intel_engine_mask_t engine_mask,
1308 			   unsigned long flags,
1309 			   const char *fmt, ...)
1310 {
1311 	struct intel_engine_cs *engine;
1312 	intel_wakeref_t wakeref;
1313 	intel_engine_mask_t tmp;
1314 	char error_msg[80];
1315 	char *msg = NULL;
1316 
1317 	if (fmt) {
1318 		va_list args;
1319 
1320 		va_start(args, fmt);
1321 		vscnprintf(error_msg, sizeof(error_msg), fmt, args);
1322 		va_end(args);
1323 
1324 		msg = error_msg;
1325 	}
1326 
1327 	/*
1328 	 * In most cases it's guaranteed that we get here with an RPM
1329 	 * reference held, for example because there is a pending GPU
1330 	 * request that won't finish until the reset is done. This
1331 	 * isn't the case at least when we get here by doing a
1332 	 * simulated reset via debugfs, so get an RPM reference.
1333 	 */
1334 	wakeref = intel_runtime_pm_get(gt->uncore->rpm);
1335 
1336 	engine_mask &= gt->info.engine_mask;
1337 
1338 	if (flags & I915_ERROR_CAPTURE) {
1339 		i915_capture_error_state(gt, engine_mask, CORE_DUMP_FLAG_NONE);
1340 		intel_gt_clear_error_registers(gt, engine_mask);
1341 	}
1342 
1343 	/*
1344 	 * Try engine reset when available. We fall back to full reset if
1345 	 * single reset fails.
1346 	 */
1347 	if (!intel_uc_uses_guc_submission(&gt->uc) &&
1348 	    intel_has_reset_engine(gt) && !intel_gt_is_wedged(gt)) {
1349 		local_bh_disable();
1350 		for_each_engine_masked(engine, gt, engine_mask, tmp) {
1351 			BUILD_BUG_ON(I915_RESET_MODESET >= I915_RESET_ENGINE);
1352 			if (test_and_set_bit(I915_RESET_ENGINE + engine->id,
1353 					     &gt->reset.flags))
1354 				continue;
1355 
1356 			if (__intel_engine_reset_bh(engine, msg) == 0)
1357 				engine_mask &= ~engine->mask;
1358 
1359 			clear_and_wake_up_bit(I915_RESET_ENGINE + engine->id,
1360 					      &gt->reset.flags);
1361 		}
1362 		local_bh_enable();
1363 	}
1364 
1365 	if (!engine_mask)
1366 		goto out;
1367 
1368 	/* Full reset needs the mutex, stop any other user trying to do so. */
1369 	if (test_and_set_bit(I915_RESET_BACKOFF, &gt->reset.flags)) {
1370 		wait_event(gt->reset.queue,
1371 			   !test_bit(I915_RESET_BACKOFF, &gt->reset.flags));
1372 		goto out; /* piggy-back on the other reset */
1373 	}
1374 
1375 	/* Make sure i915_reset_trylock() sees the I915_RESET_BACKOFF */
1376 	synchronize_rcu_expedited();
1377 
1378 	/*
1379 	 * Prevent any other reset-engine attempt. We don't do this for GuC
1380 	 * submission the GuC owns the per-engine reset, not the i915.
1381 	 */
1382 	if (!intel_uc_uses_guc_submission(&gt->uc)) {
1383 		for_each_engine(engine, gt, tmp) {
1384 			while (test_and_set_bit(I915_RESET_ENGINE + engine->id,
1385 						&gt->reset.flags))
1386 				wait_on_bit(&gt->reset.flags,
1387 					    I915_RESET_ENGINE + engine->id,
1388 					    TASK_UNINTERRUPTIBLE);
1389 		}
1390 	}
1391 
1392 	/* Flush everyone using a resource about to be clobbered */
1393 	synchronize_srcu_expedited(&gt->reset.backoff_srcu);
1394 
1395 	intel_gt_reset_global(gt, engine_mask, msg);
1396 
1397 	if (!intel_uc_uses_guc_submission(&gt->uc)) {
1398 		for_each_engine(engine, gt, tmp)
1399 			clear_bit_unlock(I915_RESET_ENGINE + engine->id,
1400 					 &gt->reset.flags);
1401 	}
1402 	clear_bit_unlock(I915_RESET_BACKOFF, &gt->reset.flags);
1403 	smp_mb__after_atomic();
1404 	wake_up_all(&gt->reset.queue);
1405 
1406 out:
1407 	intel_runtime_pm_put(gt->uncore->rpm, wakeref);
1408 }
1409 
1410 int intel_gt_reset_trylock(struct intel_gt *gt, int *srcu)
1411 {
1412 	might_lock(&gt->reset.backoff_srcu);
1413 	might_sleep();
1414 
1415 	rcu_read_lock();
1416 	while (test_bit(I915_RESET_BACKOFF, &gt->reset.flags)) {
1417 		rcu_read_unlock();
1418 
1419 		if (wait_event_interruptible(gt->reset.queue,
1420 					     !test_bit(I915_RESET_BACKOFF,
1421 						       &gt->reset.flags)))
1422 			return -EINTR;
1423 
1424 		rcu_read_lock();
1425 	}
1426 	*srcu = srcu_read_lock(&gt->reset.backoff_srcu);
1427 	rcu_read_unlock();
1428 
1429 	return 0;
1430 }
1431 
1432 void intel_gt_reset_unlock(struct intel_gt *gt, int tag)
1433 __releases(&gt->reset.backoff_srcu)
1434 {
1435 	srcu_read_unlock(&gt->reset.backoff_srcu, tag);
1436 }
1437 
1438 int intel_gt_terminally_wedged(struct intel_gt *gt)
1439 {
1440 	might_sleep();
1441 
1442 	if (!intel_gt_is_wedged(gt))
1443 		return 0;
1444 
1445 	if (intel_gt_has_unrecoverable_error(gt))
1446 		return -EIO;
1447 
1448 	/* Reset still in progress? Maybe we will recover? */
1449 	if (wait_event_interruptible(gt->reset.queue,
1450 				     !test_bit(I915_RESET_BACKOFF,
1451 					       &gt->reset.flags)))
1452 		return -EINTR;
1453 
1454 	return intel_gt_is_wedged(gt) ? -EIO : 0;
1455 }
1456 
1457 void intel_gt_set_wedged_on_init(struct intel_gt *gt)
1458 {
1459 	BUILD_BUG_ON(I915_RESET_ENGINE + I915_NUM_ENGINES >
1460 		     I915_WEDGED_ON_INIT);
1461 	intel_gt_set_wedged(gt);
1462 	i915_disable_error_state(gt->i915, -ENODEV);
1463 	set_bit(I915_WEDGED_ON_INIT, &gt->reset.flags);
1464 
1465 	/* Wedged on init is non-recoverable */
1466 	add_taint_for_CI(gt->i915, TAINT_WARN);
1467 }
1468 
1469 void intel_gt_set_wedged_on_fini(struct intel_gt *gt)
1470 {
1471 	intel_gt_set_wedged(gt);
1472 	i915_disable_error_state(gt->i915, -ENODEV);
1473 	set_bit(I915_WEDGED_ON_FINI, &gt->reset.flags);
1474 	intel_gt_retire_requests(gt); /* cleanup any wedged requests */
1475 }
1476 
1477 void intel_gt_init_reset(struct intel_gt *gt)
1478 {
1479 	init_waitqueue_head(&gt->reset.queue);
1480 	mutex_init(&gt->reset.mutex);
1481 	init_srcu_struct(&gt->reset.backoff_srcu);
1482 
1483 	/*
1484 	 * While undesirable to wait inside the shrinker, complain anyway.
1485 	 *
1486 	 * If we have to wait during shrinking, we guarantee forward progress
1487 	 * by forcing the reset. Therefore during the reset we must not
1488 	 * re-enter the shrinker. By declaring that we take the reset mutex
1489 	 * within the shrinker, we forbid ourselves from performing any
1490 	 * fs-reclaim or taking related locks during reset.
1491 	 */
1492 	i915_gem_shrinker_taints_mutex(gt->i915, &gt->reset.mutex);
1493 
1494 	/* no GPU until we are ready! */
1495 	__set_bit(I915_WEDGED, &gt->reset.flags);
1496 }
1497 
1498 void intel_gt_fini_reset(struct intel_gt *gt)
1499 {
1500 	cleanup_srcu_struct(&gt->reset.backoff_srcu);
1501 }
1502 
1503 static void intel_wedge_me(struct work_struct *work)
1504 {
1505 	struct intel_wedge_me *w = container_of(work, typeof(*w), work.work);
1506 
1507 	drm_err(&w->gt->i915->drm,
1508 		"%s timed out, cancelling all in-flight rendering.\n",
1509 		w->name);
1510 	intel_gt_set_wedged(w->gt);
1511 }
1512 
1513 void __intel_init_wedge(struct intel_wedge_me *w,
1514 			struct intel_gt *gt,
1515 			long timeout,
1516 			const char *name)
1517 {
1518 	w->gt = gt;
1519 	w->name = name;
1520 
1521 	INIT_DELAYED_WORK_ONSTACK(&w->work, intel_wedge_me);
1522 	schedule_delayed_work(&w->work, timeout);
1523 }
1524 
1525 void __intel_fini_wedge(struct intel_wedge_me *w)
1526 {
1527 	cancel_delayed_work_sync(&w->work);
1528 	destroy_delayed_work_on_stack(&w->work);
1529 	w->gt = NULL;
1530 }
1531 
1532 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
1533 #include "selftest_reset.c"
1534 #include "selftest_hangcheck.c"
1535 #endif
1536