1 files changed, 347 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_hangcheck.c b/drivers/gpu/drm/i915/gt/intel_hangcheck.c
new file mode 100644
index 000000000000..6bcfa6456c45
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_hangcheck.c
@@ -0,0 +1,347 @@
+/*
+ * 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 "intel_reset.h"
+#include "i915_drv.h"
+
+struct hangcheck {
+	u64 acthd;
+	u32 ring;
+	u32 head;
+	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 != RCS0)
+		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 = ENGINE_READ(engine, RING_CTL);
+	if (tmp & RING_WAIT) {
+		i915_handle_error(dev_priv, engine->mask, 0,
+				  "stuck wait on %s", engine->name);
+		ENGINE_WRITE(engine, RING_CTL, 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->ring = ENGINE_READ(engine, RING_START);
+	hc->head = ENGINE_READ(engine, RING_HEAD);
+}
+
+static void hangcheck_store_sample(struct intel_engine_cs *engine,
+				   const struct hangcheck *hc)
+{
+	engine->hangcheck.acthd = hc->acthd;
+	engine->hangcheck.last_ring = hc->ring;
+	engine->hangcheck.last_head = hc->head;
+}
+
+static enum intel_engine_hangcheck_action
+hangcheck_get_action(struct intel_engine_cs *engine,
+		     const struct hangcheck *hc)
+{
+	if (intel_engine_is_idle(engine))
+		return ENGINE_IDLE;
+
+	if (engine->hangcheck.last_ring != hc->ring)
+		return ENGINE_ACTIVE_SEQNO;
+
+	if (engine->hangcheck.last_head != hc->head)
+		return ENGINE_ACTIVE_SEQNO;
+
+	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,
+				   intel_engine_mask_t hung,
+				   intel_engine_mask_t stuck)
+{
+	struct intel_engine_cs *engine;
+	intel_engine_mask_t tmp;
+	char msg[80];
+	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);
+	intel_engine_mask_t hung = 0, stuck = 0, wedged = 0;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	intel_wakeref_t wakeref;
+
+	if (!i915_modparams.enable_hangcheck)
+		return;
+
+	if (!READ_ONCE(dev_priv->gt.awake))
+		return;
+
+	if (i915_terminally_wedged(dev_priv))
+		return;
+
+	wakeref = intel_runtime_pm_get_if_in_use(&dev_priv->runtime_pm);
+	if (!wakeref)
+		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->uncore);
+
+	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 |= engine->mask;
+			if (hc.action != ENGINE_DEAD)
+				stuck |= engine->mask;
+		}
+
+		if (hc.wedged)
+			wedged |= engine->mask;
+	}
+
+	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);
+
+	intel_runtime_pm_put(&dev_priv->runtime_pm, wakeref);
+
+	/* 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 "selftest_hangcheck.c"
+#endif