drivers/gpu/drm/i915/intel_hangcheck.c - linux - Git at Google

 /*
  * Copyright © 2016 Intel Corporation
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  * IN THE SOFTWARE.
  *
  */

 #include "i915_drv.h"
 #include "i915_reset.h"

 struct hangcheck {
 	u64 acthd;
 	u32 seqno;
 	enum intel_engine_hangcheck_action action;
 	unsigned long action_timestamp;
 	int deadlock;
 	struct intel_instdone instdone;
 	bool wedged:1;
 	bool stalled:1;
 };

 static bool instdone_unchanged(u32 current_instdone, u32 *old_instdone)
 {
 	u32 tmp = current_instdone | *old_instdone;
 	bool unchanged;

 	unchanged = tmp == *old_instdone;
 	*old_instdone |= tmp;

 	return unchanged;
 }

 static bool subunits_stuck(struct intel_engine_cs *engine)
 {
 	struct drm_i915_private *dev_priv = engine->i915;
 	struct intel_instdone instdone;
 	struct intel_instdone *accu_instdone = &engine->hangcheck.instdone;
 	bool stuck;
 	int slice;
 	int subslice;

 	if (engine->id != RCS)
 		return true;

 	intel_engine_get_instdone(engine, &instdone);

 	/* There might be unstable subunit states even when
 	 * actual head is not moving. Filter out the unstable ones by
 	 * accumulating the undone -> done transitions and only
 	 * consider those as progress.
 	 */
 	stuck = instdone_unchanged(instdone.instdone,
 				   &accu_instdone->instdone);
 	stuck &= instdone_unchanged(instdone.slice_common,
 				    &accu_instdone->slice_common);

 	for_each_instdone_slice_subslice(dev_priv, slice, subslice) {
 		stuck &= instdone_unchanged(instdone.sampler[slice][subslice],
 					    &accu_instdone->sampler[slice][subslice]);
 		stuck &= instdone_unchanged(instdone.row[slice][subslice],
 					    &accu_instdone->row[slice][subslice]);
 	}

 	return stuck;
 }

 static enum intel_engine_hangcheck_action
 head_stuck(struct intel_engine_cs *engine, u64 acthd)
 {
 	if (acthd != engine->hangcheck.acthd) {

 		/* Clear subunit states on head movement */
 		memset(&engine->hangcheck.instdone, 0,
 		       sizeof(engine->hangcheck.instdone));

 		return ENGINE_ACTIVE_HEAD;
 	}

 	if (!subunits_stuck(engine))
 		return ENGINE_ACTIVE_SUBUNITS;

 	return ENGINE_DEAD;
 }

 static enum intel_engine_hangcheck_action
 engine_stuck(struct intel_engine_cs *engine, u64 acthd)
 {
 	struct drm_i915_private *dev_priv = engine->i915;
 	enum intel_engine_hangcheck_action ha;
 	u32 tmp;

 	ha = head_stuck(engine, acthd);
 	if (ha != ENGINE_DEAD)
 		return ha;

 	if (IS_GEN(dev_priv, 2))
 		return ENGINE_DEAD;

 	/* Is the chip hanging on a WAIT_FOR_EVENT?
 	 * If so we can simply poke the RB_WAIT bit
 	 * and break the hang. This should work on
 	 * all but the second generation chipsets.
 	 */
 	tmp = I915_READ_CTL(engine);
 	if (tmp & RING_WAIT) {
 		i915_handle_error(dev_priv, BIT(engine->id), 0,
 				  "stuck wait on %s", engine->name);
 		I915_WRITE_CTL(engine, tmp);
 		return ENGINE_WAIT_KICK;
 	}

 	return ENGINE_DEAD;
 }

 static void hangcheck_load_sample(struct intel_engine_cs *engine,
 				  struct hangcheck *hc)
 {
 	hc->acthd = intel_engine_get_active_head(engine);
 	hc->seqno = intel_engine_get_seqno(engine);
 }

 static void hangcheck_store_sample(struct intel_engine_cs *engine,
 				   const struct hangcheck *hc)
 {
 	engine->hangcheck.acthd = hc->acthd;
 	engine->hangcheck.seqno = hc->seqno;
 }

 static enum intel_engine_hangcheck_action
 hangcheck_get_action(struct intel_engine_cs *engine,
 		     const struct hangcheck *hc)
 {
 	if (engine->hangcheck.seqno != hc->seqno)
 		return ENGINE_ACTIVE_SEQNO;

 	if (intel_engine_is_idle(engine))
 		return ENGINE_IDLE;

 	return engine_stuck(engine, hc->acthd);
 }

 static void hangcheck_accumulate_sample(struct intel_engine_cs *engine,
 					struct hangcheck *hc)
 {
 	unsigned long timeout = I915_ENGINE_DEAD_TIMEOUT;

 	hc->action = hangcheck_get_action(engine, hc);

 	/* We always increment the progress
 	 * if the engine is busy and still processing
 	 * the same request, so that no single request
 	 * can run indefinitely (such as a chain of
 	 * batches). The only time we do not increment
 	 * the hangcheck score on this ring, if this
 	 * engine is in a legitimate wait for another
 	 * engine. In that case the waiting engine is a
 	 * victim and we want to be sure we catch the
 	 * right culprit. Then every time we do kick
 	 * the ring, make it as a progress as the seqno
 	 * advancement might ensure and if not, it
 	 * will catch the hanging engine.
 	 */

 	switch (hc->action) {
 	case ENGINE_IDLE:
 	case ENGINE_ACTIVE_SEQNO:
 		/* Clear head and subunit states on seqno movement */
 		hc->acthd = 0;

 		memset(&engine->hangcheck.instdone, 0,
 		       sizeof(engine->hangcheck.instdone));

 		/* Intentional fall through */
 	case ENGINE_WAIT_KICK:
 	case ENGINE_WAIT:
 		engine->hangcheck.action_timestamp = jiffies;
 		break;

 	case ENGINE_ACTIVE_HEAD:
 	case ENGINE_ACTIVE_SUBUNITS:
 		/*
 		 * Seqno stuck with still active engine gets leeway,
 		 * in hopes that it is just a long shader.
 		 */
 		timeout = I915_SEQNO_DEAD_TIMEOUT;
 		break;

 	case ENGINE_DEAD:
 		break;

 	default:
 		MISSING_CASE(hc->action);
 	}

 	hc->stalled = time_after(jiffies,
 				 engine->hangcheck.action_timestamp + timeout);
 	hc->wedged = time_after(jiffies,
 				 engine->hangcheck.action_timestamp +
 				 I915_ENGINE_WEDGED_TIMEOUT);
 }

 static void hangcheck_declare_hang(struct drm_i915_private *i915,
 				   unsigned int hung,
 				   unsigned int stuck)
 {
 	struct intel_engine_cs *engine;
 	char msg[80];
 	unsigned int tmp;
 	int len;

 	/* If some rings hung but others were still busy, only
 	 * blame the hanging rings in the synopsis.
 	 */
 	if (stuck != hung)
 		hung &= ~stuck;
 	len = scnprintf(msg, sizeof(msg),
 			"%s on ", stuck == hung ? "no progress" : "hang");
 	for_each_engine_masked(engine, i915, hung, tmp)
 		len += scnprintf(msg + len, sizeof(msg) - len,
 				 "%s, ", engine->name);
 	msg[len-2] = '\0';

 	return i915_handle_error(i915, hung, I915_ERROR_CAPTURE, "%s", msg);
 }

 /*
  * This is called when the chip hasn't reported back with completed
  * batchbuffers in a long time. We keep track per ring seqno progress and
  * if there are no progress, hangcheck score for that ring is increased.
  * Further, acthd is inspected to see if the ring is stuck. On stuck case
  * we kick the ring. If we see no progress on three subsequent calls
  * we assume chip is wedged and try to fix it by resetting the chip.
  */
 static void i915_hangcheck_elapsed(struct work_struct *work)
 {
 	struct drm_i915_private *dev_priv =
 		container_of(work, typeof(*dev_priv),
 			     gpu_error.hangcheck_work.work);
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
 	unsigned int hung = 0, stuck = 0, wedged = 0;

 	if (!i915_modparams.enable_hangcheck)
 		return;

 	if (!READ_ONCE(dev_priv->gt.awake))
 		return;

 	if (i915_terminally_wedged(&dev_priv->gpu_error))
 		return;

 	/* As enabling the GPU requires fairly extensive mmio access,
 	 * periodically arm the mmio checker to see if we are triggering
 	 * any invalid access.
 	 */
 	intel_uncore_arm_unclaimed_mmio_detection(dev_priv);

 	for_each_engine(engine, dev_priv, id) {
 		struct hangcheck hc;

 		intel_engine_signal_breadcrumbs(engine);

 		hangcheck_load_sample(engine, &hc);
 		hangcheck_accumulate_sample(engine, &hc);
 		hangcheck_store_sample(engine, &hc);

 		if (hc.stalled) {
 			hung |= intel_engine_flag(engine);
 			if (hc.action != ENGINE_DEAD)
 				stuck |= intel_engine_flag(engine);
 		}

 		if (hc.wedged)
 			wedged |= intel_engine_flag(engine);
 	}

 	if (GEM_SHOW_DEBUG() && (hung | stuck)) {
 		struct drm_printer p = drm_debug_printer("hangcheck");

 		for_each_engine(engine, dev_priv, id) {
 			if (intel_engine_is_idle(engine))
 				continue;

 			intel_engine_dump(engine, &p, "%s\n", engine->name);
 		}
 	}

 	if (wedged) {
 		dev_err(dev_priv->drm.dev,
 			"GPU recovery timed out,"
 			" cancelling all in-flight rendering.\n");
 		GEM_TRACE_DUMP();
 		i915_gem_set_wedged(dev_priv);
 	}

 	if (hung)
 		hangcheck_declare_hang(dev_priv, hung, stuck);

 	/* Reset timer in case GPU hangs without another request being added */
 	i915_queue_hangcheck(dev_priv);
 }

 void intel_engine_init_hangcheck(struct intel_engine_cs *engine)
 {
 	memset(&engine->hangcheck, 0, sizeof(engine->hangcheck));
 	engine->hangcheck.action_timestamp = jiffies;
 }

 void intel_hangcheck_init(struct drm_i915_private *i915)
 {
 	INIT_DELAYED_WORK(&i915->gpu_error.hangcheck_work,
 			  i915_hangcheck_elapsed);
 }

 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftests/intel_hangcheck.c"
 #endif
	/*
	* Copyright © 2016 Intel Corporation
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
	* IN THE SOFTWARE.
	*
	*/

	#include "i915_drv.h"
	#include "i915_reset.h"

	struct hangcheck {
	u64 acthd;
	u32 seqno;
	enum intel_engine_hangcheck_action action;
	unsigned long action_timestamp;
	int deadlock;
	struct intel_instdone instdone;
	bool wedged:1;
	bool stalled:1;
	};

	static bool instdone_unchanged(u32 current_instdone, u32 *old_instdone)
	{
	u32 tmp = current_instdone \| *old_instdone;
	bool unchanged;

	unchanged = tmp == *old_instdone;
	*old_instdone \|= tmp;

	return unchanged;
	}

	static bool subunits_stuck(struct intel_engine_cs *engine)
	{
	struct drm_i915_private *dev_priv = engine->i915;
	struct intel_instdone instdone;
	struct intel_instdone *accu_instdone = &engine->hangcheck.instdone;
	bool stuck;
	int slice;
	int subslice;

	if (engine->id != RCS)
	return true;

	intel_engine_get_instdone(engine, &instdone);

	/* There might be unstable subunit states even when
	* actual head is not moving. Filter out the unstable ones by
	* accumulating the undone -> done transitions and only
	* consider those as progress.
	*/
	stuck = instdone_unchanged(instdone.instdone,
	&accu_instdone->instdone);
	stuck &= instdone_unchanged(instdone.slice_common,
	&accu_instdone->slice_common);

	for_each_instdone_slice_subslice(dev_priv, slice, subslice) {
	stuck &= instdone_unchanged(instdone.sampler[slice][subslice],
	&accu_instdone->sampler[slice][subslice]);
	stuck &= instdone_unchanged(instdone.row[slice][subslice],
	&accu_instdone->row[slice][subslice]);
	}

	return stuck;
	}

	static enum intel_engine_hangcheck_action
	head_stuck(struct intel_engine_cs *engine, u64 acthd)
	{
	if (acthd != engine->hangcheck.acthd) {

	/* Clear subunit states on head movement */
	memset(&engine->hangcheck.instdone, 0,
	sizeof(engine->hangcheck.instdone));

	return ENGINE_ACTIVE_HEAD;
	}

	if (!subunits_stuck(engine))
	return ENGINE_ACTIVE_SUBUNITS;

	return ENGINE_DEAD;
	}

	static enum intel_engine_hangcheck_action
	engine_stuck(struct intel_engine_cs *engine, u64 acthd)
	{
	struct drm_i915_private *dev_priv = engine->i915;
	enum intel_engine_hangcheck_action ha;
	u32 tmp;

	ha = head_stuck(engine, acthd);
	if (ha != ENGINE_DEAD)
	return ha;

	if (IS_GEN(dev_priv, 2))
	return ENGINE_DEAD;

	/* Is the chip hanging on a WAIT_FOR_EVENT?
	* If so we can simply poke the RB_WAIT bit
	* and break the hang. This should work on
	* all but the second generation chipsets.
	*/
	tmp = I915_READ_CTL(engine);
	if (tmp & RING_WAIT) {
	i915_handle_error(dev_priv, BIT(engine->id), 0,
	"stuck wait on %s", engine->name);
	I915_WRITE_CTL(engine, tmp);
	return ENGINE_WAIT_KICK;
	}

	return ENGINE_DEAD;
	}

	static void hangcheck_load_sample(struct intel_engine_cs *engine,
	struct hangcheck *hc)
	{
	hc->acthd = intel_engine_get_active_head(engine);
	hc->seqno = intel_engine_get_seqno(engine);
	}

	static void hangcheck_store_sample(struct intel_engine_cs *engine,
	const struct hangcheck *hc)
	{
	engine->hangcheck.acthd = hc->acthd;
	engine->hangcheck.seqno = hc->seqno;
	}

	static enum intel_engine_hangcheck_action
	hangcheck_get_action(struct intel_engine_cs *engine,
	const struct hangcheck *hc)
	{
	if (engine->hangcheck.seqno != hc->seqno)
	return ENGINE_ACTIVE_SEQNO;

	if (intel_engine_is_idle(engine))
	return ENGINE_IDLE;

	return engine_stuck(engine, hc->acthd);
	}

	static void hangcheck_accumulate_sample(struct intel_engine_cs *engine,
	struct hangcheck *hc)
	{
	unsigned long timeout = I915_ENGINE_DEAD_TIMEOUT;

	hc->action = hangcheck_get_action(engine, hc);

	/* We always increment the progress
	* if the engine is busy and still processing
	* the same request, so that no single request
	* can run indefinitely (such as a chain of
	* batches). The only time we do not increment
	* the hangcheck score on this ring, if this
	* engine is in a legitimate wait for another
	* engine. In that case the waiting engine is a
	* victim and we want to be sure we catch the
	* right culprit. Then every time we do kick
	* the ring, make it as a progress as the seqno
	* advancement might ensure and if not, it
	* will catch the hanging engine.
	*/

	switch (hc->action) {
	case ENGINE_IDLE:
	case ENGINE_ACTIVE_SEQNO:
	/* Clear head and subunit states on seqno movement */
	hc->acthd = 0;

	memset(&engine->hangcheck.instdone, 0,
	sizeof(engine->hangcheck.instdone));

	/* Intentional fall through */
	case ENGINE_WAIT_KICK:
	case ENGINE_WAIT:
	engine->hangcheck.action_timestamp = jiffies;
	break;

	case ENGINE_ACTIVE_HEAD:
	case ENGINE_ACTIVE_SUBUNITS:
	/*
	* Seqno stuck with still active engine gets leeway,
	* in hopes that it is just a long shader.
	*/
	timeout = I915_SEQNO_DEAD_TIMEOUT;
	break;

	case ENGINE_DEAD:
	break;

	default:
	MISSING_CASE(hc->action);
	}

	hc->stalled = time_after(jiffies,
	engine->hangcheck.action_timestamp + timeout);
	hc->wedged = time_after(jiffies,
	engine->hangcheck.action_timestamp +
	I915_ENGINE_WEDGED_TIMEOUT);
	}

	static void hangcheck_declare_hang(struct drm_i915_private *i915,
	unsigned int hung,
	unsigned int stuck)
	{
	struct intel_engine_cs *engine;
	char msg[80];
	unsigned int tmp;
	int len;

	/* If some rings hung but others were still busy, only
	* blame the hanging rings in the synopsis.
	*/
	if (stuck != hung)
	hung &= ~stuck;
	len = scnprintf(msg, sizeof(msg),
	"%s on ", stuck == hung ? "no progress" : "hang");
	for_each_engine_masked(engine, i915, hung, tmp)
	len += scnprintf(msg + len, sizeof(msg) - len,
	"%s, ", engine->name);
	msg[len-2] = '\0';

	return i915_handle_error(i915, hung, I915_ERROR_CAPTURE, "%s", msg);
	}

	/*
	* This is called when the chip hasn't reported back with completed
	* batchbuffers in a long time. We keep track per ring seqno progress and
	* if there are no progress, hangcheck score for that ring is increased.
	* Further, acthd is inspected to see if the ring is stuck. On stuck case
	* we kick the ring. If we see no progress on three subsequent calls
	* we assume chip is wedged and try to fix it by resetting the chip.
	*/
	static void i915_hangcheck_elapsed(struct work_struct *work)
	{
	struct drm_i915_private *dev_priv =
	container_of(work, typeof(*dev_priv),
	gpu_error.hangcheck_work.work);
	struct intel_engine_cs *engine;
	enum intel_engine_id id;
	unsigned int hung = 0, stuck = 0, wedged = 0;

	if (!i915_modparams.enable_hangcheck)
	return;

	if (!READ_ONCE(dev_priv->gt.awake))
	return;

	if (i915_terminally_wedged(&dev_priv->gpu_error))
	return;

	/* As enabling the GPU requires fairly extensive mmio access,
	* periodically arm the mmio checker to see if we are triggering
	* any invalid access.
	*/
	intel_uncore_arm_unclaimed_mmio_detection(dev_priv);

	for_each_engine(engine, dev_priv, id) {
	struct hangcheck hc;

	intel_engine_signal_breadcrumbs(engine);

	hangcheck_load_sample(engine, &hc);
	hangcheck_accumulate_sample(engine, &hc);
	hangcheck_store_sample(engine, &hc);

	if (hc.stalled) {
	hung \|= intel_engine_flag(engine);
	if (hc.action != ENGINE_DEAD)
	stuck \|= intel_engine_flag(engine);
	}

	if (hc.wedged)
	wedged \|= intel_engine_flag(engine);
	}

	if (GEM_SHOW_DEBUG() && (hung \| stuck)) {
	struct drm_printer p = drm_debug_printer("hangcheck");

	for_each_engine(engine, dev_priv, id) {
	if (intel_engine_is_idle(engine))
	continue;

	intel_engine_dump(engine, &p, "%s\n", engine->name);
	}
	}

	if (wedged) {
	dev_err(dev_priv->drm.dev,
	"GPU recovery timed out,"
	" cancelling all in-flight rendering.\n");
	GEM_TRACE_DUMP();
	i915_gem_set_wedged(dev_priv);
	}

	if (hung)
	hangcheck_declare_hang(dev_priv, hung, stuck);

	/* Reset timer in case GPU hangs without another request being added */
	i915_queue_hangcheck(dev_priv);
	}

	void intel_engine_init_hangcheck(struct intel_engine_cs *engine)
	{
	memset(&engine->hangcheck, 0, sizeof(engine->hangcheck));
	engine->hangcheck.action_timestamp = jiffies;
	}

	void intel_hangcheck_init(struct drm_i915_private *i915)
	{
	INIT_DELAYED_WORK(&i915->gpu_error.hangcheck_work,
	i915_hangcheck_elapsed);
	}

	#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
	#include "selftests/intel_hangcheck.c"
	#endif