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Diffstat (limited to 'drivers/gpu/drm/i915/intel_hangcheck.c')
-rw-r--r--drivers/gpu/drm/i915/intel_hangcheck.c450
1 files changed, 450 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_hangcheck.c b/drivers/gpu/drm/i915/intel_hangcheck.c
new file mode 100644
index 000000000000..53df5b11bff4
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_hangcheck.c
@@ -0,0 +1,450 @@
+/*
+ * 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"
+
+static bool
+ipehr_is_semaphore_wait(struct intel_engine_cs *engine, u32 ipehr)
+{
+ if (INTEL_GEN(engine->i915) >= 8) {
+ return (ipehr >> 23) == 0x1c;
+ } else {
+ ipehr &= ~MI_SEMAPHORE_SYNC_MASK;
+ return ipehr == (MI_SEMAPHORE_MBOX | MI_SEMAPHORE_COMPARE |
+ MI_SEMAPHORE_REGISTER);
+ }
+}
+
+static struct intel_engine_cs *
+semaphore_wait_to_signaller_ring(struct intel_engine_cs *engine, u32 ipehr,
+ u64 offset)
+{
+ struct drm_i915_private *dev_priv = engine->i915;
+ struct intel_engine_cs *signaller;
+ enum intel_engine_id id;
+
+ if (INTEL_GEN(dev_priv) >= 8) {
+ for_each_engine(signaller, dev_priv, id) {
+ if (engine == signaller)
+ continue;
+
+ if (offset == signaller->semaphore.signal_ggtt[engine->hw_id])
+ return signaller;
+ }
+ } else {
+ u32 sync_bits = ipehr & MI_SEMAPHORE_SYNC_MASK;
+
+ for_each_engine(signaller, dev_priv, id) {
+ if(engine == signaller)
+ continue;
+
+ if (sync_bits == signaller->semaphore.mbox.wait[engine->hw_id])
+ return signaller;
+ }
+ }
+
+ DRM_DEBUG_DRIVER("No signaller ring found for %s, ipehr 0x%08x, offset 0x%016llx\n",
+ engine->name, ipehr, offset);
+
+ return ERR_PTR(-ENODEV);
+}
+
+static struct intel_engine_cs *
+semaphore_waits_for(struct intel_engine_cs *engine, u32 *seqno)
+{
+ struct drm_i915_private *dev_priv = engine->i915;
+ void __iomem *vaddr;
+ u32 cmd, ipehr, head;
+ u64 offset = 0;
+ int i, backwards;
+
+ /*
+ * This function does not support execlist mode - any attempt to
+ * proceed further into this function will result in a kernel panic
+ * when dereferencing ring->buffer, which is not set up in execlist
+ * mode.
+ *
+ * The correct way of doing it would be to derive the currently
+ * executing ring buffer from the current context, which is derived
+ * from the currently running request. Unfortunately, to get the
+ * current request we would have to grab the struct_mutex before doing
+ * anything else, which would be ill-advised since some other thread
+ * might have grabbed it already and managed to hang itself, causing
+ * the hang checker to deadlock.
+ *
+ * Therefore, this function does not support execlist mode in its
+ * current form. Just return NULL and move on.
+ */
+ if (engine->buffer == NULL)
+ return NULL;
+
+ ipehr = I915_READ(RING_IPEHR(engine->mmio_base));
+ if (!ipehr_is_semaphore_wait(engine, ipehr))
+ return NULL;
+
+ /*
+ * HEAD is likely pointing to the dword after the actual command,
+ * so scan backwards until we find the MBOX. But limit it to just 3
+ * or 4 dwords depending on the semaphore wait command size.
+ * Note that we don't care about ACTHD here since that might
+ * point at at batch, and semaphores are always emitted into the
+ * ringbuffer itself.
+ */
+ head = I915_READ_HEAD(engine) & HEAD_ADDR;
+ backwards = (INTEL_GEN(dev_priv) >= 8) ? 5 : 4;
+ vaddr = (void __iomem *)engine->buffer->vaddr;
+
+ for (i = backwards; i; --i) {
+ /*
+ * Be paranoid and presume the hw has gone off into the wild -
+ * our ring is smaller than what the hardware (and hence
+ * HEAD_ADDR) allows. Also handles wrap-around.
+ */
+ head &= engine->buffer->size - 1;
+
+ /* This here seems to blow up */
+ cmd = ioread32(vaddr + head);
+ if (cmd == ipehr)
+ break;
+
+ head -= 4;
+ }
+
+ if (!i)
+ return NULL;
+
+ *seqno = ioread32(vaddr + head + 4) + 1;
+ if (INTEL_GEN(dev_priv) >= 8) {
+ offset = ioread32(vaddr + head + 12);
+ offset <<= 32;
+ offset |= ioread32(vaddr + head + 8);
+ }
+ return semaphore_wait_to_signaller_ring(engine, ipehr, offset);
+}
+
+static int semaphore_passed(struct intel_engine_cs *engine)
+{
+ struct drm_i915_private *dev_priv = engine->i915;
+ struct intel_engine_cs *signaller;
+ u32 seqno;
+
+ engine->hangcheck.deadlock++;
+
+ signaller = semaphore_waits_for(engine, &seqno);
+ if (signaller == NULL)
+ return -1;
+
+ if (IS_ERR(signaller))
+ return 0;
+
+ /* Prevent pathological recursion due to driver bugs */
+ if (signaller->hangcheck.deadlock >= I915_NUM_ENGINES)
+ return -1;
+
+ if (i915_seqno_passed(intel_engine_get_seqno(signaller), seqno))
+ return 1;
+
+ /* cursory check for an unkickable deadlock */
+ if (I915_READ_CTL(signaller) & RING_WAIT_SEMAPHORE &&
+ semaphore_passed(signaller) < 0)
+ return -1;
+
+ return 0;
+}
+
+static void semaphore_clear_deadlocks(struct drm_i915_private *dev_priv)
+{
+ struct intel_engine_cs *engine;
+ enum intel_engine_id id;
+
+ for_each_engine(engine, dev_priv, id)
+ engine->hangcheck.deadlock = 0;
+}
+
+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 HANGCHECK_ACTIVE;
+ }
+
+ if (!subunits_stuck(engine))
+ return HANGCHECK_ACTIVE;
+
+ return HANGCHECK_HUNG;
+}
+
+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 != HANGCHECK_HUNG)
+ return ha;
+
+ if (IS_GEN2(dev_priv))
+ return HANGCHECK_HUNG;
+
+ /* 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, 0,
+ "Kicking stuck wait on %s",
+ engine->name);
+ I915_WRITE_CTL(engine, tmp);
+ return HANGCHECK_KICK;
+ }
+
+ if (INTEL_GEN(dev_priv) >= 6 && tmp & RING_WAIT_SEMAPHORE) {
+ switch (semaphore_passed(engine)) {
+ default:
+ return HANGCHECK_HUNG;
+ case 1:
+ i915_handle_error(dev_priv, 0,
+ "Kicking stuck semaphore on %s",
+ engine->name);
+ I915_WRITE_CTL(engine, tmp);
+ return HANGCHECK_KICK;
+ case 0:
+ return HANGCHECK_WAIT;
+ }
+ }
+
+ return HANGCHECK_HUNG;
+}
+
+/*
+ * 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;
+ int busy_count = 0;
+#define BUSY 1
+#define KICK 5
+#define HUNG 20
+#define ACTIVE_DECAY 15
+
+ if (!i915.enable_hangcheck)
+ return;
+
+ if (!READ_ONCE(dev_priv->gt.awake))
+ 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) {
+ bool busy = intel_engine_has_waiter(engine);
+ u64 acthd;
+ u32 seqno;
+ u32 submit;
+
+ semaphore_clear_deadlocks(dev_priv);
+
+ /* We don't strictly need an irq-barrier here, as we are not
+ * serving an interrupt request, be paranoid in case the
+ * barrier has side-effects (such as preventing a broken
+ * cacheline snoop) and so be sure that we can see the seqno
+ * advance. If the seqno should stick, due to a stale
+ * cacheline, we would erroneously declare the GPU hung.
+ */
+ if (engine->irq_seqno_barrier)
+ engine->irq_seqno_barrier(engine);
+
+ acthd = intel_engine_get_active_head(engine);
+ seqno = intel_engine_get_seqno(engine);
+ submit = intel_engine_last_submit(engine);
+
+ if (engine->hangcheck.seqno == seqno) {
+ if (i915_seqno_passed(seqno, submit)) {
+ engine->hangcheck.action = HANGCHECK_IDLE;
+ } else {
+ /* We always increment the hangcheck score
+ * 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, add a small increment to the
+ * score so that we can catch a batch that is
+ * being repeatedly kicked and so responsible
+ * for stalling the machine.
+ */
+ engine->hangcheck.action =
+ engine_stuck(engine, acthd);
+
+ switch (engine->hangcheck.action) {
+ case HANGCHECK_IDLE:
+ case HANGCHECK_WAIT:
+ break;
+ case HANGCHECK_ACTIVE:
+ engine->hangcheck.score += BUSY;
+ break;
+ case HANGCHECK_KICK:
+ engine->hangcheck.score += KICK;
+ break;
+ case HANGCHECK_HUNG:
+ engine->hangcheck.score += HUNG;
+ break;
+ }
+ }
+
+ if (engine->hangcheck.score >= HANGCHECK_SCORE_RING_HUNG) {
+ hung |= intel_engine_flag(engine);
+ if (engine->hangcheck.action != HANGCHECK_HUNG)
+ stuck |= intel_engine_flag(engine);
+ }
+ } else {
+ engine->hangcheck.action = HANGCHECK_ACTIVE;
+
+ /* Gradually reduce the count so that we catch DoS
+ * attempts across multiple batches.
+ */
+ if (engine->hangcheck.score > 0)
+ engine->hangcheck.score -= ACTIVE_DECAY;
+ if (engine->hangcheck.score < 0)
+ engine->hangcheck.score = 0;
+
+ /* Clear head and subunit states on seqno movement */
+ acthd = 0;
+
+ memset(&engine->hangcheck.instdone, 0,
+ sizeof(engine->hangcheck.instdone));
+ }
+
+ engine->hangcheck.seqno = seqno;
+ engine->hangcheck.acthd = acthd;
+ busy_count += busy;
+ }
+
+ if (hung) {
+ 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, dev_priv, hung, tmp)
+ len += scnprintf(msg + len, sizeof(msg) - len,
+ "%s, ", engine->name);
+ msg[len-2] = '\0';
+
+ return i915_handle_error(dev_priv, hung, msg);
+ }
+
+ /* Reset timer in case GPU hangs without another request being added */
+ if (busy_count)
+ i915_queue_hangcheck(dev_priv);
+}
+
+void intel_engine_init_hangcheck(struct intel_engine_cs *engine)
+{
+ memset(&engine->hangcheck, 0, sizeof(engine->hangcheck));
+}
+
+void intel_hangcheck_init(struct drm_i915_private *i915)
+{
+ INIT_DELAYED_WORK(&i915->gpu_error.hangcheck_work,
+ i915_hangcheck_elapsed);
+}
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