linux/drivers/gpu/drm/i915/gt/intel_reset.c
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   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
   9#include "display/intel_display_types.h"
  10#include "display/intel_overlay.h"
  11
  12#include "gem/i915_gem_context.h"
  13
  14#include "i915_drv.h"
  15#include "i915_gpu_error.h"
  16#include "i915_irq.h"
  17#include "intel_breadcrumbs.h"
  18#include "intel_engine_pm.h"
  19#include "intel_gt.h"
  20#include "intel_gt_pm.h"
  21#include "intel_gt_requests.h"
  22#include "intel_reset.h"
  23
  24#include "uc/intel_guc.h"
  25#include "uc/intel_guc_submission.h"
  26
  27#define RESET_MAX_RETRIES 3
  28
  29/* XXX How to handle concurrent GGTT updates using tiling registers? */
  30#define RESET_UNDER_STOP_MACHINE 0
  31
  32static void rmw_set_fw(struct intel_uncore *uncore, i915_reg_t reg, u32 set)
  33{
  34        intel_uncore_rmw_fw(uncore, reg, 0, set);
  35}
  36
  37static void rmw_clear_fw(struct intel_uncore *uncore, i915_reg_t reg, u32 clr)
  38{
  39        intel_uncore_rmw_fw(uncore, reg, clr, 0);
  40}
  41
  42static void skip_context(struct i915_request *rq)
  43{
  44        struct intel_context *hung_ctx = rq->context;
  45
  46        list_for_each_entry_from_rcu(rq, &hung_ctx->timeline->requests, link) {
  47                if (!i915_request_is_active(rq))
  48                        return;
  49
  50                if (rq->context == hung_ctx) {
  51                        i915_request_set_error_once(rq, -EIO);
  52                        __i915_request_skip(rq);
  53                }
  54        }
  55}
  56
  57static void client_mark_guilty(struct i915_gem_context *ctx, bool banned)
  58{
  59        struct drm_i915_file_private *file_priv = ctx->file_priv;
  60        unsigned long prev_hang;
  61        unsigned int score;
  62
  63        if (IS_ERR_OR_NULL(file_priv))
  64                return;
  65
  66        score = 0;
  67        if (banned)
  68                score = I915_CLIENT_SCORE_CONTEXT_BAN;
  69
  70        prev_hang = xchg(&file_priv->hang_timestamp, jiffies);
  71        if (time_before(jiffies, prev_hang + I915_CLIENT_FAST_HANG_JIFFIES))
  72                score += I915_CLIENT_SCORE_HANG_FAST;
  73
  74        if (score) {
  75                atomic_add(score, &file_priv->ban_score);
  76
  77                drm_dbg(&ctx->i915->drm,
  78                        "client %s: gained %u ban score, now %u\n",
  79                        ctx->name, score,
  80                        atomic_read(&file_priv->ban_score));
  81        }
  82}
  83
  84static bool mark_guilty(struct i915_request *rq)
  85{
  86        struct i915_gem_context *ctx;
  87        unsigned long prev_hang;
  88        bool banned;
  89        int i;
  90
  91        if (intel_context_is_closed(rq->context)) {
  92                intel_context_set_banned(rq->context);
  93                return true;
  94        }
  95
  96        rcu_read_lock();
  97        ctx = rcu_dereference(rq->context->gem_context);
  98        if (ctx && !kref_get_unless_zero(&ctx->ref))
  99                ctx = NULL;
 100        rcu_read_unlock();
 101        if (!ctx)
 102                return intel_context_is_banned(rq->context);
 103
 104        atomic_inc(&ctx->guilty_count);
 105
 106        /* Cool contexts are too cool to be banned! (Used for reset testing.) */
 107        if (!i915_gem_context_is_bannable(ctx)) {
 108                banned = false;
 109                goto out;
 110        }
 111
 112        drm_notice(&ctx->i915->drm,
 113                   "%s context reset due to GPU hang\n",
 114                   ctx->name);
 115
 116        /* Record the timestamp for the last N hangs */
 117        prev_hang = ctx->hang_timestamp[0];
 118        for (i = 0; i < ARRAY_SIZE(ctx->hang_timestamp) - 1; i++)
 119                ctx->hang_timestamp[i] = ctx->hang_timestamp[i + 1];
 120        ctx->hang_timestamp[i] = jiffies;
 121
 122        /* If we have hung N+1 times in rapid succession, we ban the context! */
 123        banned = !i915_gem_context_is_recoverable(ctx);
 124        if (time_before(jiffies, prev_hang + CONTEXT_FAST_HANG_JIFFIES))
 125                banned = true;
 126        if (banned) {
 127                drm_dbg(&ctx->i915->drm, "context %s: guilty %d, banned\n",
 128                        ctx->name, atomic_read(&ctx->guilty_count));
 129                intel_context_set_banned(rq->context);
 130        }
 131
 132        client_mark_guilty(ctx, banned);
 133
 134out:
 135        i915_gem_context_put(ctx);
 136        return banned;
 137}
 138
 139static void mark_innocent(struct i915_request *rq)
 140{
 141        struct i915_gem_context *ctx;
 142
 143        rcu_read_lock();
 144        ctx = rcu_dereference(rq->context->gem_context);
 145        if (ctx)
 146                atomic_inc(&ctx->active_count);
 147        rcu_read_unlock();
 148}
 149
 150void __i915_request_reset(struct i915_request *rq, bool guilty)
 151{
 152        RQ_TRACE(rq, "guilty? %s\n", yesno(guilty));
 153        GEM_BUG_ON(__i915_request_is_complete(rq));
 154
 155        rcu_read_lock(); /* protect the GEM context */
 156        if (guilty) {
 157                i915_request_set_error_once(rq, -EIO);
 158                __i915_request_skip(rq);
 159                if (mark_guilty(rq))
 160                        skip_context(rq);
 161        } else {
 162                i915_request_set_error_once(rq, -EAGAIN);
 163                mark_innocent(rq);
 164        }
 165        rcu_read_unlock();
 166}
 167
 168static bool i915_in_reset(struct pci_dev *pdev)
 169{
 170        u8 gdrst;
 171
 172        pci_read_config_byte(pdev, I915_GDRST, &gdrst);
 173        return gdrst & GRDOM_RESET_STATUS;
 174}
 175
 176static int i915_do_reset(struct intel_gt *gt,
 177                         intel_engine_mask_t engine_mask,
 178                         unsigned int retry)
 179{
 180        struct pci_dev *pdev = to_pci_dev(gt->i915->drm.dev);
 181        int err;
 182
 183        /* Assert reset for at least 20 usec, and wait for acknowledgement. */
 184        pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE);
 185        udelay(50);
 186        err = wait_for_atomic(i915_in_reset(pdev), 50);
 187
 188        /* Clear the reset request. */
 189        pci_write_config_byte(pdev, I915_GDRST, 0);
 190        udelay(50);
 191        if (!err)
 192                err = wait_for_atomic(!i915_in_reset(pdev), 50);
 193
 194        return err;
 195}
 196
 197static bool g4x_reset_complete(struct pci_dev *pdev)
 198{
 199        u8 gdrst;
 200
 201        pci_read_config_byte(pdev, I915_GDRST, &gdrst);
 202        return (gdrst & GRDOM_RESET_ENABLE) == 0;
 203}
 204
 205static int g33_do_reset(struct intel_gt *gt,
 206                        intel_engine_mask_t engine_mask,
 207                        unsigned int retry)
 208{
 209        struct pci_dev *pdev = to_pci_dev(gt->i915->drm.dev);
 210
 211        pci_write_config_byte(pdev, I915_GDRST, GRDOM_RESET_ENABLE);
 212        return wait_for_atomic(g4x_reset_complete(pdev), 50);
 213}
 214
 215static int g4x_do_reset(struct intel_gt *gt,
 216                        intel_engine_mask_t engine_mask,
 217                        unsigned int retry)
 218{
 219        struct pci_dev *pdev = to_pci_dev(gt->i915->drm.dev);
 220        struct intel_uncore *uncore = gt->uncore;
 221        int ret;
 222
 223        /* WaVcpClkGateDisableForMediaReset:ctg,elk */
 224        rmw_set_fw(uncore, VDECCLK_GATE_D, VCP_UNIT_CLOCK_GATE_DISABLE);
 225        intel_uncore_posting_read_fw(uncore, VDECCLK_GATE_D);
 226
 227        pci_write_config_byte(pdev, I915_GDRST,
 228                              GRDOM_MEDIA | GRDOM_RESET_ENABLE);
 229        ret =  wait_for_atomic(g4x_reset_complete(pdev), 50);
 230        if (ret) {
 231                GT_TRACE(gt, "Wait for media reset failed\n");
 232                goto out;
 233        }
 234
 235        pci_write_config_byte(pdev, I915_GDRST,
 236                              GRDOM_RENDER | GRDOM_RESET_ENABLE);
 237        ret =  wait_for_atomic(g4x_reset_complete(pdev), 50);
 238        if (ret) {
 239                GT_TRACE(gt, "Wait for render reset failed\n");
 240                goto out;
 241        }
 242
 243out:
 244        pci_write_config_byte(pdev, I915_GDRST, 0);
 245
 246        rmw_clear_fw(uncore, VDECCLK_GATE_D, VCP_UNIT_CLOCK_GATE_DISABLE);
 247        intel_uncore_posting_read_fw(uncore, VDECCLK_GATE_D);
 248
 249        return ret;
 250}
 251
 252static int ilk_do_reset(struct intel_gt *gt, intel_engine_mask_t engine_mask,
 253                        unsigned int retry)
 254{
 255        struct intel_uncore *uncore = gt->uncore;
 256        int ret;
 257
 258        intel_uncore_write_fw(uncore, ILK_GDSR,
 259                              ILK_GRDOM_RENDER | ILK_GRDOM_RESET_ENABLE);
 260        ret = __intel_wait_for_register_fw(uncore, ILK_GDSR,
 261                                           ILK_GRDOM_RESET_ENABLE, 0,
 262                                           5000, 0,
 263                                           NULL);
 264        if (ret) {
 265                GT_TRACE(gt, "Wait for render reset failed\n");
 266                goto out;
 267        }
 268
 269        intel_uncore_write_fw(uncore, ILK_GDSR,
 270                              ILK_GRDOM_MEDIA | ILK_GRDOM_RESET_ENABLE);
 271        ret = __intel_wait_for_register_fw(uncore, ILK_GDSR,
 272                                           ILK_GRDOM_RESET_ENABLE, 0,
 273                                           5000, 0,
 274                                           NULL);
 275        if (ret) {
 276                GT_TRACE(gt, "Wait for media reset failed\n");
 277                goto out;
 278        }
 279
 280out:
 281        intel_uncore_write_fw(uncore, ILK_GDSR, 0);
 282        intel_uncore_posting_read_fw(uncore, ILK_GDSR);
 283        return ret;
 284}
 285
 286/* Reset the hardware domains (GENX_GRDOM_*) specified by mask */
 287static int gen6_hw_domain_reset(struct intel_gt *gt, u32 hw_domain_mask)
 288{
 289        struct intel_uncore *uncore = gt->uncore;
 290        int err;
 291
 292        /*
 293         * GEN6_GDRST is not in the gt power well, no need to check
 294         * for fifo space for the write or forcewake the chip for
 295         * the read
 296         */
 297        intel_uncore_write_fw(uncore, GEN6_GDRST, hw_domain_mask);
 298
 299        /* Wait for the device to ack the reset requests */
 300        err = __intel_wait_for_register_fw(uncore,
 301                                           GEN6_GDRST, hw_domain_mask, 0,
 302                                           500, 0,
 303                                           NULL);
 304        if (err)
 305                GT_TRACE(gt,
 306                         "Wait for 0x%08x engines reset failed\n",
 307                         hw_domain_mask);
 308
 309        return err;
 310}
 311
 312static int gen6_reset_engines(struct intel_gt *gt,
 313                              intel_engine_mask_t engine_mask,
 314                              unsigned int retry)
 315{
 316        static const u32 hw_engine_mask[] = {
 317                [RCS0]  = GEN6_GRDOM_RENDER,
 318                [BCS0]  = GEN6_GRDOM_BLT,
 319                [VCS0]  = GEN6_GRDOM_MEDIA,
 320                [VCS1]  = GEN8_GRDOM_MEDIA2,
 321                [VECS0] = GEN6_GRDOM_VECS,
 322        };
 323        struct intel_engine_cs *engine;
 324        u32 hw_mask;
 325
 326        if (engine_mask == ALL_ENGINES) {
 327                hw_mask = GEN6_GRDOM_FULL;
 328        } else {
 329                intel_engine_mask_t tmp;
 330
 331                hw_mask = 0;
 332                for_each_engine_masked(engine, gt, engine_mask, tmp) {
 333                        GEM_BUG_ON(engine->id >= ARRAY_SIZE(hw_engine_mask));
 334                        hw_mask |= hw_engine_mask[engine->id];
 335                }
 336        }
 337
 338        return gen6_hw_domain_reset(gt, hw_mask);
 339}
 340
 341static struct intel_engine_cs *find_sfc_paired_vecs_engine(struct intel_engine_cs *engine)
 342{
 343        int vecs_id;
 344
 345        GEM_BUG_ON(engine->class != VIDEO_DECODE_CLASS);
 346
 347        vecs_id = _VECS((engine->instance) / 2);
 348
 349        return engine->gt->engine[vecs_id];
 350}
 351
 352struct sfc_lock_data {
 353        i915_reg_t lock_reg;
 354        i915_reg_t ack_reg;
 355        i915_reg_t usage_reg;
 356        u32 lock_bit;
 357        u32 ack_bit;
 358        u32 usage_bit;
 359        u32 reset_bit;
 360};
 361
 362static void get_sfc_forced_lock_data(struct intel_engine_cs *engine,
 363                                     struct sfc_lock_data *sfc_lock)
 364{
 365        switch (engine->class) {
 366        default:
 367                MISSING_CASE(engine->class);
 368                fallthrough;
 369        case VIDEO_DECODE_CLASS:
 370                sfc_lock->lock_reg = GEN11_VCS_SFC_FORCED_LOCK(engine);
 371                sfc_lock->lock_bit = GEN11_VCS_SFC_FORCED_LOCK_BIT;
 372
 373                sfc_lock->ack_reg = GEN11_VCS_SFC_LOCK_STATUS(engine);
 374                sfc_lock->ack_bit  = GEN11_VCS_SFC_LOCK_ACK_BIT;
 375
 376                sfc_lock->usage_reg = GEN11_VCS_SFC_LOCK_STATUS(engine);
 377                sfc_lock->usage_bit = GEN11_VCS_SFC_USAGE_BIT;
 378                sfc_lock->reset_bit = GEN11_VCS_SFC_RESET_BIT(engine->instance);
 379
 380                break;
 381        case VIDEO_ENHANCEMENT_CLASS:
 382                sfc_lock->lock_reg = GEN11_VECS_SFC_FORCED_LOCK(engine);
 383                sfc_lock->lock_bit = GEN11_VECS_SFC_FORCED_LOCK_BIT;
 384
 385                sfc_lock->ack_reg = GEN11_VECS_SFC_LOCK_ACK(engine);
 386                sfc_lock->ack_bit  = GEN11_VECS_SFC_LOCK_ACK_BIT;
 387
 388                sfc_lock->usage_reg = GEN11_VECS_SFC_USAGE(engine);
 389                sfc_lock->usage_bit = GEN11_VECS_SFC_USAGE_BIT;
 390                sfc_lock->reset_bit = GEN11_VECS_SFC_RESET_BIT(engine->instance);
 391
 392                break;
 393        }
 394}
 395
 396static int gen11_lock_sfc(struct intel_engine_cs *engine,
 397                          u32 *reset_mask,
 398                          u32 *unlock_mask)
 399{
 400        struct intel_uncore *uncore = engine->uncore;
 401        u8 vdbox_sfc_access = engine->gt->info.vdbox_sfc_access;
 402        struct sfc_lock_data sfc_lock;
 403        bool lock_obtained, lock_to_other = false;
 404        int ret;
 405
 406        switch (engine->class) {
 407        case VIDEO_DECODE_CLASS:
 408                if ((BIT(engine->instance) & vdbox_sfc_access) == 0)
 409                        return 0;
 410
 411                fallthrough;
 412        case VIDEO_ENHANCEMENT_CLASS:
 413                get_sfc_forced_lock_data(engine, &sfc_lock);
 414
 415                break;
 416        default:
 417                return 0;
 418        }
 419
 420        if (!(intel_uncore_read_fw(uncore, sfc_lock.usage_reg) & sfc_lock.usage_bit)) {
 421                struct intel_engine_cs *paired_vecs;
 422
 423                if (engine->class != VIDEO_DECODE_CLASS ||
 424                    GRAPHICS_VER(engine->i915) != 12)
 425                        return 0;
 426
 427                /*
 428                 * Wa_14010733141
 429                 *
 430                 * If the VCS-MFX isn't using the SFC, we also need to check
 431                 * whether VCS-HCP is using it.  If so, we need to issue a *VE*
 432                 * forced lock on the VE engine that shares the same SFC.
 433                 */
 434                if (!(intel_uncore_read_fw(uncore,
 435                                           GEN12_HCP_SFC_LOCK_STATUS(engine)) &
 436                      GEN12_HCP_SFC_USAGE_BIT))
 437                        return 0;
 438
 439                paired_vecs = find_sfc_paired_vecs_engine(engine);
 440                get_sfc_forced_lock_data(paired_vecs, &sfc_lock);
 441                lock_to_other = true;
 442                *unlock_mask |= paired_vecs->mask;
 443        } else {
 444                *unlock_mask |= engine->mask;
 445        }
 446
 447        /*
 448         * If the engine is using an SFC, tell the engine that a software reset
 449         * is going to happen. The engine will then try to force lock the SFC.
 450         * If SFC ends up being locked to the engine we want to reset, we have
 451         * to reset it as well (we will unlock it once the reset sequence is
 452         * completed).
 453         */
 454        rmw_set_fw(uncore, sfc_lock.lock_reg, sfc_lock.lock_bit);
 455
 456        ret = __intel_wait_for_register_fw(uncore,
 457                                           sfc_lock.ack_reg,
 458                                           sfc_lock.ack_bit,
 459                                           sfc_lock.ack_bit,
 460                                           1000, 0, NULL);
 461
 462        /*
 463         * Was the SFC released while we were trying to lock it?
 464         *
 465         * We should reset both the engine and the SFC if:
 466         *  - We were locking the SFC to this engine and the lock succeeded
 467         *       OR
 468         *  - We were locking the SFC to a different engine (Wa_14010733141)
 469         *    but the SFC was released before the lock was obtained.
 470         *
 471         * Otherwise we need only reset the engine by itself and we can
 472         * leave the SFC alone.
 473         */
 474        lock_obtained = (intel_uncore_read_fw(uncore, sfc_lock.usage_reg) &
 475                        sfc_lock.usage_bit) != 0;
 476        if (lock_obtained == lock_to_other)
 477                return 0;
 478
 479        if (ret) {
 480                ENGINE_TRACE(engine, "Wait for SFC forced lock ack failed\n");
 481                return ret;
 482        }
 483
 484        *reset_mask |= sfc_lock.reset_bit;
 485        return 0;
 486}
 487
 488static void gen11_unlock_sfc(struct intel_engine_cs *engine)
 489{
 490        struct intel_uncore *uncore = engine->uncore;
 491        u8 vdbox_sfc_access = engine->gt->info.vdbox_sfc_access;
 492        struct sfc_lock_data sfc_lock = {};
 493
 494        if (engine->class != VIDEO_DECODE_CLASS &&
 495            engine->class != VIDEO_ENHANCEMENT_CLASS)
 496                return;
 497
 498        if (engine->class == VIDEO_DECODE_CLASS &&
 499            (BIT(engine->instance) & vdbox_sfc_access) == 0)
 500                return;
 501
 502        get_sfc_forced_lock_data(engine, &sfc_lock);
 503
 504        rmw_clear_fw(uncore, sfc_lock.lock_reg, sfc_lock.lock_bit);
 505}
 506
 507static int gen11_reset_engines(struct intel_gt *gt,
 508                               intel_engine_mask_t engine_mask,
 509                               unsigned int retry)
 510{
 511        static const u32 hw_engine_mask[] = {
 512                [RCS0]  = GEN11_GRDOM_RENDER,
 513                [BCS0]  = GEN11_GRDOM_BLT,
 514                [VCS0]  = GEN11_GRDOM_MEDIA,
 515                [VCS1]  = GEN11_GRDOM_MEDIA2,
 516                [VCS2]  = GEN11_GRDOM_MEDIA3,
 517                [VCS3]  = GEN11_GRDOM_MEDIA4,
 518                [VECS0] = GEN11_GRDOM_VECS,
 519                [VECS1] = GEN11_GRDOM_VECS2,
 520        };
 521        struct intel_engine_cs *engine;
 522        intel_engine_mask_t tmp;
 523        u32 reset_mask, unlock_mask = 0;
 524        int ret;
 525
 526        if (engine_mask == ALL_ENGINES) {
 527                reset_mask = GEN11_GRDOM_FULL;
 528        } else {
 529                reset_mask = 0;
 530                for_each_engine_masked(engine, gt, engine_mask, tmp) {
 531                        GEM_BUG_ON(engine->id >= ARRAY_SIZE(hw_engine_mask));
 532                        reset_mask |= hw_engine_mask[engine->id];
 533                        ret = gen11_lock_sfc(engine, &reset_mask, &unlock_mask);
 534                        if (ret)
 535                                goto sfc_unlock;
 536                }
 537        }
 538
 539        ret = gen6_hw_domain_reset(gt, reset_mask);
 540
 541sfc_unlock:
 542        /*
 543         * We unlock the SFC based on the lock status and not the result of
 544         * gen11_lock_sfc to make sure that we clean properly if something
 545         * wrong happened during the lock (e.g. lock acquired after timeout
 546         * expiration).
 547         *
 548         * Due to Wa_14010733141, we may have locked an SFC to an engine that
 549         * wasn't being reset.  So instead of calling gen11_unlock_sfc()
 550         * on engine_mask, we instead call it on the mask of engines that our
 551         * gen11_lock_sfc() calls told us actually had locks attempted.
 552         */
 553        for_each_engine_masked(engine, gt, unlock_mask, tmp)
 554                gen11_unlock_sfc(engine);
 555
 556        return ret;
 557}
 558
 559static int gen8_engine_reset_prepare(struct intel_engine_cs *engine)
 560{
 561        struct intel_uncore *uncore = engine->uncore;
 562        const i915_reg_t reg = RING_RESET_CTL(engine->mmio_base);
 563        u32 request, mask, ack;
 564        int ret;
 565
 566        if (I915_SELFTEST_ONLY(should_fail(&engine->reset_timeout, 1)))
 567                return -ETIMEDOUT;
 568
 569        ack = intel_uncore_read_fw(uncore, reg);
 570        if (ack & RESET_CTL_CAT_ERROR) {
 571                /*
 572                 * For catastrophic errors, ready-for-reset sequence
 573                 * needs to be bypassed: HAS#396813
 574                 */
 575                request = RESET_CTL_CAT_ERROR;
 576                mask = RESET_CTL_CAT_ERROR;
 577
 578                /* Catastrophic errors need to be cleared by HW */
 579                ack = 0;
 580        } else if (!(ack & RESET_CTL_READY_TO_RESET)) {
 581                request = RESET_CTL_REQUEST_RESET;
 582                mask = RESET_CTL_READY_TO_RESET;
 583                ack = RESET_CTL_READY_TO_RESET;
 584        } else {
 585                return 0;
 586        }
 587
 588        intel_uncore_write_fw(uncore, reg, _MASKED_BIT_ENABLE(request));
 589        ret = __intel_wait_for_register_fw(uncore, reg, mask, ack,
 590                                           700, 0, NULL);
 591        if (ret)
 592                drm_err(&engine->i915->drm,
 593                        "%s reset request timed out: {request: %08x, RESET_CTL: %08x}\n",
 594                        engine->name, request,
 595                        intel_uncore_read_fw(uncore, reg));
 596
 597        return ret;
 598}
 599
 600static void gen8_engine_reset_cancel(struct intel_engine_cs *engine)
 601{
 602        intel_uncore_write_fw(engine->uncore,
 603                              RING_RESET_CTL(engine->mmio_base),
 604                              _MASKED_BIT_DISABLE(RESET_CTL_REQUEST_RESET));
 605}
 606
 607static int gen8_reset_engines(struct intel_gt *gt,
 608                              intel_engine_mask_t engine_mask,
 609                              unsigned int retry)
 610{
 611        struct intel_engine_cs *engine;
 612        const bool reset_non_ready = retry >= 1;
 613        intel_engine_mask_t tmp;
 614        int ret;
 615
 616        for_each_engine_masked(engine, gt, engine_mask, tmp) {
 617                ret = gen8_engine_reset_prepare(engine);
 618                if (ret && !reset_non_ready)
 619                        goto skip_reset;
 620
 621                /*
 622                 * If this is not the first failed attempt to prepare,
 623                 * we decide to proceed anyway.
 624                 *
 625                 * By doing so we risk context corruption and with
 626                 * some gens (kbl), possible system hang if reset
 627                 * happens during active bb execution.
 628                 *
 629                 * We rather take context corruption instead of
 630                 * failed reset with a wedged driver/gpu. And
 631                 * active bb execution case should be covered by
 632                 * stop_engines() we have before the reset.
 633                 */
 634        }
 635
 636        if (GRAPHICS_VER(gt->i915) >= 11)
 637                ret = gen11_reset_engines(gt, engine_mask, retry);
 638        else
 639                ret = gen6_reset_engines(gt, engine_mask, retry);
 640
 641skip_reset:
 642        for_each_engine_masked(engine, gt, engine_mask, tmp)
 643                gen8_engine_reset_cancel(engine);
 644
 645        return ret;
 646}
 647
 648static int mock_reset(struct intel_gt *gt,
 649                      intel_engine_mask_t mask,
 650                      unsigned int retry)
 651{
 652        return 0;
 653}
 654
 655typedef int (*reset_func)(struct intel_gt *,
 656                          intel_engine_mask_t engine_mask,
 657                          unsigned int retry);
 658
 659static 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
 681int __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
 708bool 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
 716bool 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
 724int 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 */
 743static 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
 757static 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->ggtt_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
 788static 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_each_engine(engine, gt, id) {
 795                if (intel_engine_pm_get_if_awake(engine))
 796                        awake |= engine->mask;
 797                reset_prepare_engine(engine);
 798        }
 799
 800        intel_uc_reset_prepare(&gt->uc);
 801
 802        return awake;
 803}
 804
 805static void gt_revoke(struct intel_gt *gt)
 806{
 807        revoke_mmaps(gt);
 808}
 809
 810static int gt_reset(struct intel_gt *gt, intel_engine_mask_t stalled_mask)
 811{
 812        struct intel_engine_cs *engine;
 813        enum intel_engine_id id;
 814        int err;
 815
 816        /*
 817         * Everything depends on having the GTT running, so we need to start
 818         * there.
 819         */
 820        err = i915_ggtt_enable_hw(gt->i915);
 821        if (err)
 822                return err;
 823
 824        local_bh_disable();
 825        for_each_engine(engine, gt, id)
 826                __intel_engine_reset(engine, stalled_mask & engine->mask);
 827        local_bh_enable();
 828
 829        intel_ggtt_restore_fences(gt->ggtt);
 830
 831        return err;
 832}
 833
 834static void reset_finish_engine(struct intel_engine_cs *engine)
 835{
 836        if (engine->reset.finish)
 837                engine->reset.finish(engine);
 838        intel_uncore_forcewake_put(engine->uncore, FORCEWAKE_ALL);
 839
 840        intel_engine_signal_breadcrumbs(engine);
 841}
 842
 843static void reset_finish(struct intel_gt *gt, intel_engine_mask_t awake)
 844{
 845        struct intel_engine_cs *engine;
 846        enum intel_engine_id id;
 847
 848        for_each_engine(engine, gt, id) {
 849                reset_finish_engine(engine);
 850                if (awake & engine->mask)
 851                        intel_engine_pm_put(engine);
 852        }
 853}
 854
 855static void nop_submit_request(struct i915_request *request)
 856{
 857        RQ_TRACE(request, "-EIO\n");
 858
 859        request = i915_request_mark_eio(request);
 860        if (request) {
 861                i915_request_submit(request);
 862                intel_engine_signal_breadcrumbs(request->engine);
 863
 864                i915_request_put(request);
 865        }
 866}
 867
 868static void __intel_gt_set_wedged(struct intel_gt *gt)
 869{
 870        struct intel_engine_cs *engine;
 871        intel_engine_mask_t awake;
 872        enum intel_engine_id id;
 873
 874        if (test_bit(I915_WEDGED, &gt->reset.flags))
 875                return;
 876
 877        GT_TRACE(gt, "start\n");
 878
 879        /*
 880         * First, stop submission to hw, but do not yet complete requests by
 881         * rolling the global seqno forward (since this would complete requests
 882         * for which we haven't set the fence error to EIO yet).
 883         */
 884        awake = reset_prepare(gt);
 885
 886        /* Even if the GPU reset fails, it should still stop the engines */
 887        if (!INTEL_INFO(gt->i915)->gpu_reset_clobbers_display)
 888                __intel_gt_reset(gt, ALL_ENGINES);
 889
 890        for_each_engine(engine, gt, id)
 891                engine->submit_request = nop_submit_request;
 892
 893        /*
 894         * Make sure no request can slip through without getting completed by
 895         * either this call here to intel_engine_write_global_seqno, or the one
 896         * in nop_submit_request.
 897         */
 898        synchronize_rcu_expedited();
 899        set_bit(I915_WEDGED, &gt->reset.flags);
 900
 901        /* Mark all executing requests as skipped */
 902        local_bh_disable();
 903        for_each_engine(engine, gt, id)
 904                if (engine->reset.cancel)
 905                        engine->reset.cancel(engine);
 906        local_bh_enable();
 907
 908        reset_finish(gt, awake);
 909
 910        GT_TRACE(gt, "end\n");
 911}
 912
 913void intel_gt_set_wedged(struct intel_gt *gt)
 914{
 915        intel_wakeref_t wakeref;
 916
 917        if (test_bit(I915_WEDGED, &gt->reset.flags))
 918                return;
 919
 920        wakeref = intel_runtime_pm_get(gt->uncore->rpm);
 921        mutex_lock(&gt->reset.mutex);
 922
 923        if (GEM_SHOW_DEBUG()) {
 924                struct drm_printer p = drm_debug_printer(__func__);
 925                struct intel_engine_cs *engine;
 926                enum intel_engine_id id;
 927
 928                drm_printf(&p, "called from %pS\n", (void *)_RET_IP_);
 929                for_each_engine(engine, gt, id) {
 930                        if (intel_engine_is_idle(engine))
 931                                continue;
 932
 933                        intel_engine_dump(engine, &p, "%s\n", engine->name);
 934                }
 935        }
 936
 937        __intel_gt_set_wedged(gt);
 938
 939        mutex_unlock(&gt->reset.mutex);
 940        intel_runtime_pm_put(gt->uncore->rpm, wakeref);
 941}
 942
 943static bool __intel_gt_unset_wedged(struct intel_gt *gt)
 944{
 945        struct intel_gt_timelines *timelines = &gt->timelines;
 946        struct intel_timeline *tl;
 947        bool ok;
 948
 949        if (!test_bit(I915_WEDGED, &gt->reset.flags))
 950                return true;
 951
 952        /* Never fully initialised, recovery impossible */
 953        if (intel_gt_has_unrecoverable_error(gt))
 954                return false;
 955
 956        GT_TRACE(gt, "start\n");
 957
 958        /*
 959         * Before unwedging, make sure that all pending operations
 960         * are flushed and errored out - we may have requests waiting upon
 961         * third party fences. We marked all inflight requests as EIO, and
 962         * every execbuf since returned EIO, for consistency we want all
 963         * the currently pending requests to also be marked as EIO, which
 964         * is done inside our nop_submit_request - and so we must wait.
 965         *
 966         * No more can be submitted until we reset the wedged bit.
 967         */
 968        spin_lock(&timelines->lock);
 969        list_for_each_entry(tl, &timelines->active_list, link) {
 970                struct dma_fence *fence;
 971
 972                fence = i915_active_fence_get(&tl->last_request);
 973                if (!fence)
 974                        continue;
 975
 976                spin_unlock(&timelines->lock);
 977
 978                /*
 979                 * All internal dependencies (i915_requests) will have
 980                 * been flushed by the set-wedge, but we may be stuck waiting
 981                 * for external fences. These should all be capped to 10s
 982                 * (I915_FENCE_TIMEOUT) so this wait should not be unbounded
 983                 * in the worst case.
 984                 */
 985                dma_fence_default_wait(fence, false, MAX_SCHEDULE_TIMEOUT);
 986                dma_fence_put(fence);
 987
 988                /* Restart iteration after droping lock */
 989                spin_lock(&timelines->lock);
 990                tl = list_entry(&timelines->active_list, typeof(*tl), link);
 991        }
 992        spin_unlock(&timelines->lock);
 993
 994        /* We must reset pending GPU events before restoring our submission */
 995        ok = !HAS_EXECLISTS(gt->i915); /* XXX better agnosticism desired */
 996        if (!INTEL_INFO(gt->i915)->gpu_reset_clobbers_display)
 997                ok = __intel_gt_reset(gt, ALL_ENGINES) == 0;
 998        if (!ok) {
 999                /*
1000                 * Warn CI about the unrecoverable wedged condition.
1001                 * Time for a reboot.
1002                 */
1003                add_taint_for_CI(gt->i915, TAINT_WARN);
1004                return false;
1005        }
1006
1007        /*
1008         * Undo nop_submit_request. We prevent all new i915 requests from
1009         * being queued (by disallowing execbuf whilst wedged) so having
1010         * waited for all active requests above, we know the system is idle
1011         * and do not have to worry about a thread being inside
1012         * engine->submit_request() as we swap over. So unlike installing
1013         * the nop_submit_request on reset, we can do this from normal
1014         * context and do not require stop_machine().
1015         */
1016        intel_engines_reset_default_submission(gt);
1017
1018        GT_TRACE(gt, "end\n");
1019
1020        smp_mb__before_atomic(); /* complete takeover before enabling execbuf */
1021        clear_bit(I915_WEDGED, &gt->reset.flags);
1022
1023        return true;
1024}
1025
1026bool intel_gt_unset_wedged(struct intel_gt *gt)
1027{
1028        bool result;
1029
1030        mutex_lock(&gt->reset.mutex);
1031        result = __intel_gt_unset_wedged(gt);
1032        mutex_unlock(&gt->reset.mutex);
1033
1034        return result;
1035}
1036
1037static int do_reset(struct intel_gt *gt, intel_engine_mask_t stalled_mask)
1038{
1039        int err, i;
1040
1041        err = __intel_gt_reset(gt, ALL_ENGINES);
1042        for (i = 0; err && i < RESET_MAX_RETRIES; i++) {
1043                msleep(10 * (i + 1));
1044                err = __intel_gt_reset(gt, ALL_ENGINES);
1045        }
1046        if (err)
1047                return err;
1048
1049        return gt_reset(gt, stalled_mask);
1050}
1051
1052static int resume(struct intel_gt *gt)
1053{
1054        struct intel_engine_cs *engine;
1055        enum intel_engine_id id;
1056        int ret;
1057
1058        for_each_engine(engine, gt, id) {
1059                ret = intel_engine_resume(engine);
1060                if (ret)
1061                        return ret;
1062        }
1063
1064        return 0;
1065}
1066
1067/**
1068 * intel_gt_reset - reset chip after a hang
1069 * @gt: #intel_gt to reset
1070 * @stalled_mask: mask of the stalled engines with the guilty requests
1071 * @reason: user error message for why we are resetting
1072 *
1073 * Reset the chip.  Useful if a hang is detected. Marks the device as wedged
1074 * on failure.
1075 *
1076 * Procedure is fairly simple:
1077 *   - reset the chip using the reset reg
1078 *   - re-init context state
1079 *   - re-init hardware status page
1080 *   - re-init ring buffer
1081 *   - re-init interrupt state
1082 *   - re-init display
1083 */
1084void intel_gt_reset(struct intel_gt *gt,
1085                    intel_engine_mask_t stalled_mask,
1086                    const char *reason)
1087{
1088        intel_engine_mask_t awake;
1089        int ret;
1090
1091        GT_TRACE(gt, "flags=%lx\n", gt->reset.flags);
1092
1093        might_sleep();
1094        GEM_BUG_ON(!test_bit(I915_RESET_BACKOFF, &gt->reset.flags));
1095
1096        /*
1097         * FIXME: Revoking cpu mmap ptes cannot be done from a dma_fence
1098         * critical section like gpu reset.
1099         */
1100        gt_revoke(gt);
1101
1102        mutex_lock(&gt->reset.mutex);
1103
1104        /* Clear any previous failed attempts at recovery. Time to try again. */
1105        if (!__intel_gt_unset_wedged(gt))
1106                goto unlock;
1107
1108        if (reason)
1109                drm_notice(&gt->i915->drm,
1110                           "Resetting chip for %s\n", reason);
1111        atomic_inc(&gt->i915->gpu_error.reset_count);
1112
1113        awake = reset_prepare(gt);
1114
1115        if (!intel_has_gpu_reset(gt)) {
1116                if (gt->i915->params.reset)
1117                        drm_err(&gt->i915->drm, "GPU reset not supported\n");
1118                else
1119                        drm_dbg(&gt->i915->drm, "GPU reset disabled\n");
1120                goto error;
1121        }
1122
1123        if (INTEL_INFO(gt->i915)->gpu_reset_clobbers_display)
1124                intel_runtime_pm_disable_interrupts(gt->i915);
1125
1126        if (do_reset(gt, stalled_mask)) {
1127                drm_err(&gt->i915->drm, "Failed to reset chip\n");
1128                goto taint;
1129        }
1130
1131        if (INTEL_INFO(gt->i915)->gpu_reset_clobbers_display)
1132                intel_runtime_pm_enable_interrupts(gt->i915);
1133
1134        intel_overlay_reset(gt->i915);
1135
1136        /*
1137         * Next we need to restore the context, but we don't use those
1138         * yet either...
1139         *
1140         * Ring buffer needs to be re-initialized in the KMS case, or if X
1141         * was running at the time of the reset (i.e. we weren't VT
1142         * switched away).
1143         */
1144        ret = intel_gt_init_hw(gt);
1145        if (ret) {
1146                drm_err(&gt->i915->drm,
1147                        "Failed to initialise HW following reset (%d)\n",
1148                        ret);
1149                goto taint;
1150        }
1151
1152        ret = resume(gt);
1153        if (ret)
1154                goto taint;
1155
1156finish:
1157        reset_finish(gt, awake);
1158unlock:
1159        mutex_unlock(&gt->reset.mutex);
1160        return;
1161
1162taint:
1163        /*
1164         * History tells us that if we cannot reset the GPU now, we
1165         * never will. This then impacts everything that is run
1166         * subsequently. On failing the reset, we mark the driver
1167         * as wedged, preventing further execution on the GPU.
1168         * We also want to go one step further and add a taint to the
1169         * kernel so that any subsequent faults can be traced back to
1170         * this failure. This is important for CI, where if the
1171         * GPU/driver fails we would like to reboot and restart testing
1172         * rather than continue on into oblivion. For everyone else,
1173         * the system should still plod along, but they have been warned!
1174         */
1175        add_taint_for_CI(gt->i915, TAINT_WARN);
1176error:
1177        __intel_gt_set_wedged(gt);
1178        goto finish;
1179}
1180
1181static int intel_gt_reset_engine(struct intel_engine_cs *engine)
1182{
1183        return __intel_gt_reset(engine->gt, engine->mask);
1184}
1185
1186int __intel_engine_reset_bh(struct intel_engine_cs *engine, const char *msg)
1187{
1188        struct intel_gt *gt = engine->gt;
1189        int ret;
1190
1191        ENGINE_TRACE(engine, "flags=%lx\n", gt->reset.flags);
1192        GEM_BUG_ON(!test_bit(I915_RESET_ENGINE + engine->id, &gt->reset.flags));
1193
1194        if (!intel_engine_pm_get_if_awake(engine))
1195                return 0;
1196
1197        reset_prepare_engine(engine);
1198
1199        if (msg)
1200                drm_notice(&engine->i915->drm,
1201                           "Resetting %s for %s\n", engine->name, msg);
1202        atomic_inc(&engine->i915->gpu_error.reset_engine_count[engine->uabi_class]);
1203
1204        if (intel_engine_uses_guc(engine))
1205                ret = intel_guc_reset_engine(&engine->gt->uc.guc, engine);
1206        else
1207                ret = intel_gt_reset_engine(engine);
1208        if (ret) {
1209                /* If we fail here, we expect to fallback to a global reset */
1210                ENGINE_TRACE(engine, "Failed to reset, err: %d\n", ret);
1211                goto out;
1212        }
1213
1214        /*
1215         * The request that caused the hang is stuck on elsp, we know the
1216         * active request and can drop it, adjust head to skip the offending
1217         * request to resume executing remaining requests in the queue.
1218         */
1219        __intel_engine_reset(engine, true);
1220
1221        /*
1222         * The engine and its registers (and workarounds in case of render)
1223         * have been reset to their default values. Follow the init_ring
1224         * process to program RING_MODE, HWSP and re-enable submission.
1225         */
1226        ret = intel_engine_resume(engine);
1227
1228out:
1229        intel_engine_cancel_stop_cs(engine);
1230        reset_finish_engine(engine);
1231        intel_engine_pm_put_async(engine);
1232        return ret;
1233}
1234
1235/**
1236 * intel_engine_reset - reset GPU engine to recover from a hang
1237 * @engine: engine to reset
1238 * @msg: reason for GPU reset; or NULL for no drm_notice()
1239 *
1240 * Reset a specific GPU engine. Useful if a hang is detected.
1241 * Returns zero on successful reset or otherwise an error code.
1242 *
1243 * Procedure is:
1244 *  - identifies the request that caused the hang and it is dropped
1245 *  - reset engine (which will force the engine to idle)
1246 *  - re-init/configure engine
1247 */
1248int intel_engine_reset(struct intel_engine_cs *engine, const char *msg)
1249{
1250        int err;
1251
1252        local_bh_disable();
1253        err = __intel_engine_reset_bh(engine, msg);
1254        local_bh_enable();
1255
1256        return err;
1257}
1258
1259static void intel_gt_reset_global(struct intel_gt *gt,
1260                                  u32 engine_mask,
1261                                  const char *reason)
1262{
1263        struct kobject *kobj = &gt->i915->drm.primary->kdev->kobj;
1264        char *error_event[] = { I915_ERROR_UEVENT "=1", NULL };
1265        char *reset_event[] = { I915_RESET_UEVENT "=1", NULL };
1266        char *reset_done_event[] = { I915_ERROR_UEVENT "=0", NULL };
1267        struct intel_wedge_me w;
1268
1269        kobject_uevent_env(kobj, KOBJ_CHANGE, error_event);
1270
1271        GT_TRACE(gt, "resetting chip, engines=%x\n", engine_mask);
1272        kobject_uevent_env(kobj, KOBJ_CHANGE, reset_event);
1273
1274        /* Use a watchdog to ensure that our reset completes */
1275        intel_wedge_on_timeout(&w, gt, 5 * HZ) {
1276                intel_display_prepare_reset(gt->i915);
1277
1278                /* Flush everyone using a resource about to be clobbered */
1279                synchronize_srcu_expedited(&gt->reset.backoff_srcu);
1280
1281                intel_gt_reset(gt, engine_mask, reason);
1282
1283                intel_display_finish_reset(gt->i915);
1284        }
1285
1286        if (!test_bit(I915_WEDGED, &gt->reset.flags))
1287                kobject_uevent_env(kobj, KOBJ_CHANGE, reset_done_event);
1288}
1289
1290/**
1291 * intel_gt_handle_error - handle a gpu error
1292 * @gt: the intel_gt
1293 * @engine_mask: mask representing engines that are hung
1294 * @flags: control flags
1295 * @fmt: Error message format string
1296 *
1297 * Do some basic checking of register state at error time and
1298 * dump it to the syslog.  Also call i915_capture_error_state() to make
1299 * sure we get a record and make it available in debugfs.  Fire a uevent
1300 * so userspace knows something bad happened (should trigger collection
1301 * of a ring dump etc.).
1302 */
1303void intel_gt_handle_error(struct intel_gt *gt,
1304                           intel_engine_mask_t engine_mask,
1305                           unsigned long flags,
1306                           const char *fmt, ...)
1307{
1308        struct intel_engine_cs *engine;
1309        intel_wakeref_t wakeref;
1310        intel_engine_mask_t tmp;
1311        char error_msg[80];
1312        char *msg = NULL;
1313
1314        if (fmt) {
1315                va_list args;
1316
1317                va_start(args, fmt);
1318                vscnprintf(error_msg, sizeof(error_msg), fmt, args);
1319                va_end(args);
1320
1321                msg = error_msg;
1322        }
1323
1324        /*
1325         * In most cases it's guaranteed that we get here with an RPM
1326         * reference held, for example because there is a pending GPU
1327         * request that won't finish until the reset is done. This
1328         * isn't the case at least when we get here by doing a
1329         * simulated reset via debugfs, so get an RPM reference.
1330         */
1331        wakeref = intel_runtime_pm_get(gt->uncore->rpm);
1332
1333        engine_mask &= gt->info.engine_mask;
1334
1335        if (flags & I915_ERROR_CAPTURE) {
1336                i915_capture_error_state(gt, engine_mask);
1337                intel_gt_clear_error_registers(gt, engine_mask);
1338        }
1339
1340        /*
1341         * Try engine reset when available. We fall back to full reset if
1342         * single reset fails.
1343         */
1344        if (intel_has_reset_engine(gt) && !intel_gt_is_wedged(gt)) {
1345                local_bh_disable();
1346                for_each_engine_masked(engine, gt, engine_mask, tmp) {
1347                        BUILD_BUG_ON(I915_RESET_MODESET >= I915_RESET_ENGINE);
1348                        if (test_and_set_bit(I915_RESET_ENGINE + engine->id,
1349                                             &gt->reset.flags))
1350                                continue;
1351
1352                        if (__intel_engine_reset_bh(engine, msg) == 0)
1353                                engine_mask &= ~engine->mask;
1354
1355                        clear_and_wake_up_bit(I915_RESET_ENGINE + engine->id,
1356                                              &gt->reset.flags);
1357                }
1358                local_bh_enable();
1359        }
1360
1361        if (!engine_mask)
1362                goto out;
1363
1364        /* Full reset needs the mutex, stop any other user trying to do so. */
1365        if (test_and_set_bit(I915_RESET_BACKOFF, &gt->reset.flags)) {
1366                wait_event(gt->reset.queue,
1367                           !test_bit(I915_RESET_BACKOFF, &gt->reset.flags));
1368                goto out; /* piggy-back on the other reset */
1369        }
1370
1371        /* Make sure i915_reset_trylock() sees the I915_RESET_BACKOFF */
1372        synchronize_rcu_expedited();
1373
1374        /* Prevent any other reset-engine attempt. */
1375        for_each_engine(engine, gt, tmp) {
1376                while (test_and_set_bit(I915_RESET_ENGINE + engine->id,
1377                                        &gt->reset.flags))
1378                        wait_on_bit(&gt->reset.flags,
1379                                    I915_RESET_ENGINE + engine->id,
1380                                    TASK_UNINTERRUPTIBLE);
1381        }
1382
1383        intel_gt_reset_global(gt, engine_mask, msg);
1384
1385        for_each_engine(engine, gt, tmp)
1386                clear_bit_unlock(I915_RESET_ENGINE + engine->id,
1387                                 &gt->reset.flags);
1388        clear_bit_unlock(I915_RESET_BACKOFF, &gt->reset.flags);
1389        smp_mb__after_atomic();
1390        wake_up_all(&gt->reset.queue);
1391
1392out:
1393        intel_runtime_pm_put(gt->uncore->rpm, wakeref);
1394}
1395
1396int intel_gt_reset_trylock(struct intel_gt *gt, int *srcu)
1397{
1398        might_lock(&gt->reset.backoff_srcu);
1399        might_sleep();
1400
1401        rcu_read_lock();
1402        while (test_bit(I915_RESET_BACKOFF, &gt->reset.flags)) {
1403                rcu_read_unlock();
1404
1405                if (wait_event_interruptible(gt->reset.queue,
1406                                             !test_bit(I915_RESET_BACKOFF,
1407                                                       &gt->reset.flags)))
1408                        return -EINTR;
1409
1410                rcu_read_lock();
1411        }
1412        *srcu = srcu_read_lock(&gt->reset.backoff_srcu);
1413        rcu_read_unlock();
1414
1415        return 0;
1416}
1417
1418void intel_gt_reset_unlock(struct intel_gt *gt, int tag)
1419__releases(&gt->reset.backoff_srcu)
1420{
1421        srcu_read_unlock(&gt->reset.backoff_srcu, tag);
1422}
1423
1424int intel_gt_terminally_wedged(struct intel_gt *gt)
1425{
1426        might_sleep();
1427
1428        if (!intel_gt_is_wedged(gt))
1429                return 0;
1430
1431        if (intel_gt_has_unrecoverable_error(gt))
1432                return -EIO;
1433
1434        /* Reset still in progress? Maybe we will recover? */
1435        if (wait_event_interruptible(gt->reset.queue,
1436                                     !test_bit(I915_RESET_BACKOFF,
1437                                               &gt->reset.flags)))
1438                return -EINTR;
1439
1440        return intel_gt_is_wedged(gt) ? -EIO : 0;
1441}
1442
1443void intel_gt_set_wedged_on_init(struct intel_gt *gt)
1444{
1445        BUILD_BUG_ON(I915_RESET_ENGINE + I915_NUM_ENGINES >
1446                     I915_WEDGED_ON_INIT);
1447        intel_gt_set_wedged(gt);
1448        set_bit(I915_WEDGED_ON_INIT, &gt->reset.flags);
1449
1450        /* Wedged on init is non-recoverable */
1451        add_taint_for_CI(gt->i915, TAINT_WARN);
1452}
1453
1454void intel_gt_set_wedged_on_fini(struct intel_gt *gt)
1455{
1456        intel_gt_set_wedged(gt);
1457        set_bit(I915_WEDGED_ON_FINI, &gt->reset.flags);
1458        intel_gt_retire_requests(gt); /* cleanup any wedged requests */
1459}
1460
1461void intel_gt_init_reset(struct intel_gt *gt)
1462{
1463        init_waitqueue_head(&gt->reset.queue);
1464        mutex_init(&gt->reset.mutex);
1465        init_srcu_struct(&gt->reset.backoff_srcu);
1466
1467        /*
1468         * While undesirable to wait inside the shrinker, complain anyway.
1469         *
1470         * If we have to wait during shrinking, we guarantee forward progress
1471         * by forcing the reset. Therefore during the reset we must not
1472         * re-enter the shrinker. By declaring that we take the reset mutex
1473         * within the shrinker, we forbid ourselves from performing any
1474         * fs-reclaim or taking related locks during reset.
1475         */
1476        i915_gem_shrinker_taints_mutex(gt->i915, &gt->reset.mutex);
1477
1478        /* no GPU until we are ready! */
1479        __set_bit(I915_WEDGED, &gt->reset.flags);
1480}
1481
1482void intel_gt_fini_reset(struct intel_gt *gt)
1483{
1484        cleanup_srcu_struct(&gt->reset.backoff_srcu);
1485}
1486
1487static void intel_wedge_me(struct work_struct *work)
1488{
1489        struct intel_wedge_me *w = container_of(work, typeof(*w), work.work);
1490
1491        drm_err(&w->gt->i915->drm,
1492                "%s timed out, cancelling all in-flight rendering.\n",
1493                w->name);
1494        intel_gt_set_wedged(w->gt);
1495}
1496
1497void __intel_init_wedge(struct intel_wedge_me *w,
1498                        struct intel_gt *gt,
1499                        long timeout,
1500                        const char *name)
1501{
1502        w->gt = gt;
1503        w->name = name;
1504
1505        INIT_DELAYED_WORK_ONSTACK(&w->work, intel_wedge_me);
1506        schedule_delayed_work(&w->work, timeout);
1507}
1508
1509void __intel_fini_wedge(struct intel_wedge_me *w)
1510{
1511        cancel_delayed_work_sync(&w->work);
1512        destroy_delayed_work_on_stack(&w->work);
1513        w->gt = NULL;
1514}
1515
1516#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
1517#include "selftest_reset.c"
1518#include "selftest_hangcheck.c"
1519#endif
1520