root/drivers/gpu/drm/i915/gt/intel_hangcheck.c

DEFINITIONS

1. instdone_unchanged
2. subunits_stuck
3. head_stuck
4. engine_stuck
5. hangcheck_load_sample
6. hangcheck_store_sample
7. hangcheck_get_action
8. hangcheck_accumulate_sample
9. hangcheck_declare_hang
10. hangcheck_elapsed
11. intel_gt_queue_hangcheck
12. intel_engine_init_hangcheck
13. intel_gt_init_hangcheck

   1 /*
   2  * Copyright © 2016 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  */
  24 
  25 #include "i915_drv.h"
  26 #include "intel_engine.h"
  27 #include "intel_gt.h"
  28 #include "intel_reset.h"
  29 
  30 struct hangcheck {
  31         u64 acthd;
  32         u32 ring;
  33         u32 head;
  34         enum intel_engine_hangcheck_action action;
  35         unsigned long action_timestamp;
  36         int deadlock;
  37         struct intel_instdone instdone;
  38         bool wedged:1;
  39         bool stalled:1;
  40 };
  41 
  42 static bool instdone_unchanged(u32 current_instdone, u32 *old_instdone)
  43 {
  44         u32 tmp = current_instdone | *old_instdone;
  45         bool unchanged;
  46 
  47         unchanged = tmp == *old_instdone;
  48         *old_instdone |= tmp;
  49 
  50         return unchanged;
  51 }
  52 
  53 static bool subunits_stuck(struct intel_engine_cs *engine)
  54 {
  55         struct drm_i915_private *dev_priv = engine->i915;
  56         struct intel_instdone instdone;
  57         struct intel_instdone *accu_instdone = &engine->hangcheck.instdone;
  58         bool stuck;
  59         int slice;
  60         int subslice;
  61 
  62         intel_engine_get_instdone(engine, &instdone);
  63 
  64         /* There might be unstable subunit states even when
  65          * actual head is not moving. Filter out the unstable ones by
  66          * accumulating the undone -> done transitions and only
  67          * consider those as progress.
  68          */
  69         stuck = instdone_unchanged(instdone.instdone,
  70                                    &accu_instdone->instdone);
  71         stuck &= instdone_unchanged(instdone.slice_common,
  72                                     &accu_instdone->slice_common);
  73 
  74         for_each_instdone_slice_subslice(dev_priv, slice, subslice) {
  75                 stuck &= instdone_unchanged(instdone.sampler[slice][subslice],
  76                                             &accu_instdone->sampler[slice][subslice]);
  77                 stuck &= instdone_unchanged(instdone.row[slice][subslice],
  78                                             &accu_instdone->row[slice][subslice]);
  79         }
  80 
  81         return stuck;
  82 }
  83 
  84 static enum intel_engine_hangcheck_action
  85 head_stuck(struct intel_engine_cs *engine, u64 acthd)
  86 {
  87         if (acthd != engine->hangcheck.acthd) {
  88 
  89                 /* Clear subunit states on head movement */
  90                 memset(&engine->hangcheck.instdone, 0,
  91                        sizeof(engine->hangcheck.instdone));
  92 
  93                 return ENGINE_ACTIVE_HEAD;
  94         }
  95 
  96         if (!subunits_stuck(engine))
  97                 return ENGINE_ACTIVE_SUBUNITS;
  98 
  99         return ENGINE_DEAD;
 100 }
 101 
 102 static enum intel_engine_hangcheck_action
 103 engine_stuck(struct intel_engine_cs *engine, u64 acthd)
 104 {
 105         enum intel_engine_hangcheck_action ha;
 106         u32 tmp;
 107 
 108         ha = head_stuck(engine, acthd);
 109         if (ha != ENGINE_DEAD)
 110                 return ha;
 111 
 112         if (IS_GEN(engine->i915, 2))
 113                 return ENGINE_DEAD;
 114 
 115         /* Is the chip hanging on a WAIT_FOR_EVENT?
 116          * If so we can simply poke the RB_WAIT bit
 117          * and break the hang. This should work on
 118          * all but the second generation chipsets.
 119          */
 120         tmp = ENGINE_READ(engine, RING_CTL);
 121         if (tmp & RING_WAIT) {
 122                 intel_gt_handle_error(engine->gt, engine->mask, 0,
 123                                       "stuck wait on %s", engine->name);
 124                 ENGINE_WRITE(engine, RING_CTL, tmp);
 125                 return ENGINE_WAIT_KICK;
 126         }
 127 
 128         return ENGINE_DEAD;
 129 }
 130 
 131 static void hangcheck_load_sample(struct intel_engine_cs *engine,
 132                                   struct hangcheck *hc)
 133 {
 134         hc->acthd = intel_engine_get_active_head(engine);
 135         hc->ring = ENGINE_READ(engine, RING_START);
 136         hc->head = ENGINE_READ(engine, RING_HEAD);
 137 }
 138 
 139 static void hangcheck_store_sample(struct intel_engine_cs *engine,
 140                                    const struct hangcheck *hc)
 141 {
 142         engine->hangcheck.acthd = hc->acthd;
 143         engine->hangcheck.last_ring = hc->ring;
 144         engine->hangcheck.last_head = hc->head;
 145 }
 146 
 147 static enum intel_engine_hangcheck_action
 148 hangcheck_get_action(struct intel_engine_cs *engine,
 149                      const struct hangcheck *hc)
 150 {
 151         if (intel_engine_is_idle(engine))
 152                 return ENGINE_IDLE;
 153 
 154         if (engine->hangcheck.last_ring != hc->ring)
 155                 return ENGINE_ACTIVE_SEQNO;
 156 
 157         if (engine->hangcheck.last_head != hc->head)
 158                 return ENGINE_ACTIVE_SEQNO;
 159 
 160         return engine_stuck(engine, hc->acthd);
 161 }
 162 
 163 static void hangcheck_accumulate_sample(struct intel_engine_cs *engine,
 164                                         struct hangcheck *hc)
 165 {
 166         unsigned long timeout = I915_ENGINE_DEAD_TIMEOUT;
 167 
 168         hc->action = hangcheck_get_action(engine, hc);
 169 
 170         /* We always increment the progress
 171          * if the engine is busy and still processing
 172          * the same request, so that no single request
 173          * can run indefinitely (such as a chain of
 174          * batches). The only time we do not increment
 175          * the hangcheck score on this ring, if this
 176          * engine is in a legitimate wait for another
 177          * engine. In that case the waiting engine is a
 178          * victim and we want to be sure we catch the
 179          * right culprit. Then every time we do kick
 180          * the ring, make it as a progress as the seqno
 181          * advancement might ensure and if not, it
 182          * will catch the hanging engine.
 183          */
 184 
 185         switch (hc->action) {
 186         case ENGINE_IDLE:
 187         case ENGINE_ACTIVE_SEQNO:
 188                 /* Clear head and subunit states on seqno movement */
 189                 hc->acthd = 0;
 190 
 191                 memset(&engine->hangcheck.instdone, 0,
 192                        sizeof(engine->hangcheck.instdone));
 193 
 194                 /* Intentional fall through */
 195         case ENGINE_WAIT_KICK:
 196         case ENGINE_WAIT:
 197                 engine->hangcheck.action_timestamp = jiffies;
 198                 break;
 199 
 200         case ENGINE_ACTIVE_HEAD:
 201         case ENGINE_ACTIVE_SUBUNITS:
 202                 /*
 203                  * Seqno stuck with still active engine gets leeway,
 204                  * in hopes that it is just a long shader.
 205                  */
 206                 timeout = I915_SEQNO_DEAD_TIMEOUT;
 207                 break;
 208 
 209         case ENGINE_DEAD:
 210                 break;
 211 
 212         default:
 213                 MISSING_CASE(hc->action);
 214         }
 215 
 216         hc->stalled = time_after(jiffies,
 217                                  engine->hangcheck.action_timestamp + timeout);
 218         hc->wedged = time_after(jiffies,
 219                                  engine->hangcheck.action_timestamp +
 220                                  I915_ENGINE_WEDGED_TIMEOUT);
 221 }
 222 
 223 static void hangcheck_declare_hang(struct intel_gt *gt,
 224                                    intel_engine_mask_t hung,
 225                                    intel_engine_mask_t stuck)
 226 {
 227         struct intel_engine_cs *engine;
 228         intel_engine_mask_t tmp;
 229         char msg[80];
 230         int len;
 231 
 232         /* If some rings hung but others were still busy, only
 233          * blame the hanging rings in the synopsis.
 234          */
 235         if (stuck != hung)
 236                 hung &= ~stuck;
 237         len = scnprintf(msg, sizeof(msg),
 238                         "%s on ", stuck == hung ? "no progress" : "hang");
 239         for_each_engine_masked(engine, gt->i915, hung, tmp)
 240                 len += scnprintf(msg + len, sizeof(msg) - len,
 241                                  "%s, ", engine->name);
 242         msg[len-2] = '\0';
 243 
 244         return intel_gt_handle_error(gt, hung, I915_ERROR_CAPTURE, "%s", msg);
 245 }
 246 
 247 /*
 248  * This is called when the chip hasn't reported back with completed
 249  * batchbuffers in a long time. We keep track per ring seqno progress and
 250  * if there are no progress, hangcheck score for that ring is increased.
 251  * Further, acthd is inspected to see if the ring is stuck. On stuck case
 252  * we kick the ring. If we see no progress on three subsequent calls
 253  * we assume chip is wedged and try to fix it by resetting the chip.
 254  */
 255 static void hangcheck_elapsed(struct work_struct *work)
 256 {
 257         struct intel_gt *gt =
 258                 container_of(work, typeof(*gt), hangcheck.work.work);
 259         intel_engine_mask_t hung = 0, stuck = 0, wedged = 0;
 260         struct intel_engine_cs *engine;
 261         enum intel_engine_id id;
 262         intel_wakeref_t wakeref;
 263 
 264         if (!i915_modparams.enable_hangcheck)
 265                 return;
 266 
 267         if (!READ_ONCE(gt->awake))
 268                 return;
 269 
 270         if (intel_gt_is_wedged(gt))
 271                 return;
 272 
 273         wakeref = intel_runtime_pm_get_if_in_use(&gt->i915->runtime_pm);
 274         if (!wakeref)
 275                 return;
 276 
 277         /* As enabling the GPU requires fairly extensive mmio access,
 278          * periodically arm the mmio checker to see if we are triggering
 279          * any invalid access.
 280          */
 281         intel_uncore_arm_unclaimed_mmio_detection(gt->uncore);
 282 
 283         for_each_engine(engine, gt->i915, id) {
 284                 struct hangcheck hc;
 285 
 286                 intel_engine_signal_breadcrumbs(engine);
 287 
 288                 hangcheck_load_sample(engine, &hc);
 289                 hangcheck_accumulate_sample(engine, &hc);
 290                 hangcheck_store_sample(engine, &hc);
 291 
 292                 if (hc.stalled) {
 293                         hung |= engine->mask;
 294                         if (hc.action != ENGINE_DEAD)
 295                                 stuck |= engine->mask;
 296                 }
 297 
 298                 if (hc.wedged)
 299                         wedged |= engine->mask;
 300         }
 301 
 302         if (GEM_SHOW_DEBUG() && (hung | stuck)) {
 303                 struct drm_printer p = drm_debug_printer("hangcheck");
 304 
 305                 for_each_engine(engine, gt->i915, id) {
 306                         if (intel_engine_is_idle(engine))
 307                                 continue;
 308 
 309                         intel_engine_dump(engine, &p, "%s\n", engine->name);
 310                 }
 311         }
 312 
 313         if (wedged) {
 314                 dev_err(gt->i915->drm.dev,
 315                         "GPU recovery timed out,"
 316                         " cancelling all in-flight rendering.\n");
 317                 GEM_TRACE_DUMP();
 318                 intel_gt_set_wedged(gt);
 319         }
 320 
 321         if (hung)
 322                 hangcheck_declare_hang(gt, hung, stuck);
 323 
 324         intel_runtime_pm_put(&gt->i915->runtime_pm, wakeref);
 325 
 326         /* Reset timer in case GPU hangs without another request being added */
 327         intel_gt_queue_hangcheck(gt);
 328 }
 329 
 330 void intel_gt_queue_hangcheck(struct intel_gt *gt)
 331 {
 332         unsigned long delay;
 333 
 334         if (unlikely(!i915_modparams.enable_hangcheck))
 335                 return;
 336 
 337         /*
 338          * Don't continually defer the hangcheck so that it is always run at
 339          * least once after work has been scheduled on any ring. Otherwise,
 340          * we will ignore a hung ring if a second ring is kept busy.
 341          */
 342 
 343         delay = round_jiffies_up_relative(DRM_I915_HANGCHECK_JIFFIES);
 344         queue_delayed_work(system_long_wq, &gt->hangcheck.work, delay);
 345 }
 346 
 347 void intel_engine_init_hangcheck(struct intel_engine_cs *engine)
 348 {
 349         memset(&engine->hangcheck, 0, sizeof(engine->hangcheck));
 350         engine->hangcheck.action_timestamp = jiffies;
 351 }
 352 
 353 void intel_gt_init_hangcheck(struct intel_gt *gt)
 354 {
 355         INIT_DELAYED_WORK(&gt->hangcheck.work, hangcheck_elapsed);
 356 }
 357 
 358 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 359 #include "selftest_hangcheck.c"
 360 #endif