drm/msm: devcoredump iommu fault support
authorRob Clark <robdclark@chromium.org>
Thu, 10 Jun 2021 21:44:13 +0000 (14:44 -0700)
committerRob Clark <robdclark@chromium.org>
Wed, 23 Jun 2021 14:33:55 +0000 (07:33 -0700)
Wire up support to stall the SMMU on iova fault, and collect a devcore-
dump snapshot for easier debugging of faults.

Currently this is a6xx-only, but mostly only because so far it is the
only one using adreno-smmu-priv.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Acked-by: Jordan Crouse <jordan@cosmicpenguin.net>
Link: https://lore.kernel.org/r/20210610214431.539029-6-robdclark@gmail.com
Signed-off-by: Rob Clark <robdclark@chromium.org>
drivers/gpu/drm/msm/adreno/a5xx_gpu.c
drivers/gpu/drm/msm/adreno/a6xx_gpu.c
drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c
drivers/gpu/drm/msm/adreno/adreno_gpu.c
drivers/gpu/drm/msm/msm_gem.h
drivers/gpu/drm/msm/msm_gem_submit.c
drivers/gpu/drm/msm/msm_gpu.c
drivers/gpu/drm/msm/msm_gpu.h
drivers/gpu/drm/msm/msm_gpummu.c
drivers/gpu/drm/msm/msm_iommu.c
drivers/gpu/drm/msm/msm_mmu.h

index eb030b0..7a271de 100644 (file)
@@ -1200,6 +1200,15 @@ static void a5xx_fault_detect_irq(struct msm_gpu *gpu)
        struct drm_device *dev = gpu->dev;
        struct msm_ringbuffer *ring = gpu->funcs->active_ring(gpu);
 
+       /*
+        * If stalled on SMMU fault, we could trip the GPU's hang detection,
+        * but the fault handler will trigger the devcore dump, and we want
+        * to otherwise resume normally rather than killing the submit, so
+        * just bail.
+        */
+       if (gpu_read(gpu, REG_A5XX_RBBM_STATUS3) & BIT(24))
+               return;
+
        DRM_DEV_ERROR(dev->dev, "gpu fault ring %d fence %x status %8.8X rb %4.4x/%4.4x ib1 %16.16llX/%4.4x ib2 %16.16llX/%4.4x\n",
                ring ? ring->id : -1, ring ? ring->seqno : 0,
                gpu_read(gpu, REG_A5XX_RBBM_STATUS),
@@ -1523,6 +1532,7 @@ static struct msm_gpu_state *a5xx_gpu_state_get(struct msm_gpu *gpu)
 {
        struct a5xx_gpu_state *a5xx_state = kzalloc(sizeof(*a5xx_state),
                        GFP_KERNEL);
+       bool stalled = !!(gpu_read(gpu, REG_A5XX_RBBM_STATUS3) & BIT(24));
 
        if (!a5xx_state)
                return ERR_PTR(-ENOMEM);
@@ -1535,8 +1545,13 @@ static struct msm_gpu_state *a5xx_gpu_state_get(struct msm_gpu *gpu)
 
        a5xx_state->base.rbbm_status = gpu_read(gpu, REG_A5XX_RBBM_STATUS);
 
-       /* Get the HLSQ regs with the help of the crashdumper */
-       a5xx_gpu_state_get_hlsq_regs(gpu, a5xx_state);
+       /*
+        * Get the HLSQ regs with the help of the crashdumper, but only if
+        * we are not stalled in an iommu fault (in which case the crashdumper
+        * would not have access to memory)
+        */
+       if (!stalled)
+               a5xx_gpu_state_get_hlsq_regs(gpu, a5xx_state);
 
        a5xx_set_hwcg(gpu, true);
 
index 0d39e8f..9c5e461 100644 (file)
@@ -1193,6 +1193,16 @@ static int a6xx_fault_handler(void *arg, unsigned long iova, int flags, void *da
        struct msm_gpu *gpu = arg;
        struct adreno_smmu_fault_info *info = data;
        const char *type = "UNKNOWN";
+       const char *block;
+       bool do_devcoredump = info && !READ_ONCE(gpu->crashstate);
+
+       /*
+        * If we aren't going to be resuming later from fault_worker, then do
+        * it now.
+        */
+       if (!do_devcoredump) {
+               gpu->aspace->mmu->funcs->resume_translation(gpu->aspace->mmu);
+       }
 
        /*
         * Print a default message if we couldn't get the data from the
@@ -1216,15 +1226,30 @@ static int a6xx_fault_handler(void *arg, unsigned long iova, int flags, void *da
        else if (info->fsr & ARM_SMMU_FSR_EF)
                type = "EXTERNAL";
 
+       block = a6xx_fault_block(gpu, info->fsynr1 & 0xff);
+
        pr_warn_ratelimited("*** gpu fault: ttbr0=%.16llx iova=%.16lx dir=%s type=%s source=%s (%u,%u,%u,%u)\n",
                        info->ttbr0, iova,
-                       flags & IOMMU_FAULT_WRITE ? "WRITE" : "READ", type,
-                       a6xx_fault_block(gpu, info->fsynr1 & 0xff),
+                       flags & IOMMU_FAULT_WRITE ? "WRITE" : "READ",
+                       type, block,
                        gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(4)),
                        gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(5)),
                        gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(6)),
                        gpu_read(gpu, REG_A6XX_CP_SCRATCH_REG(7)));
 
+       if (do_devcoredump) {
+               /* Turn off the hangcheck timer to keep it from bothering us */
+               del_timer(&gpu->hangcheck_timer);
+
+               gpu->fault_info.ttbr0 = info->ttbr0;
+               gpu->fault_info.iova  = iova;
+               gpu->fault_info.flags = flags;
+               gpu->fault_info.type  = type;
+               gpu->fault_info.block = block;
+
+               kthread_queue_work(gpu->worker, &gpu->fault_work);
+       }
+
        return 0;
 }
 
@@ -1276,6 +1301,15 @@ static void a6xx_fault_detect_irq(struct msm_gpu *gpu)
        struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
        struct msm_ringbuffer *ring = gpu->funcs->active_ring(gpu);
 
+       /*
+        * If stalled on SMMU fault, we could trip the GPU's hang detection,
+        * but the fault handler will trigger the devcore dump, and we want
+        * to otherwise resume normally rather than killing the submit, so
+        * just bail.
+        */
+       if (gpu_read(gpu, REG_A6XX_RBBM_STATUS3) & A6XX_RBBM_STATUS3_SMMU_STALLED_ON_FAULT)
+               return;
+
        /*
         * Force the GPU to stay on until after we finish
         * collecting information
index 21c49c5..ad4ea0e 100644 (file)
@@ -832,6 +832,20 @@ static void a6xx_get_registers(struct msm_gpu *gpu,
                a6xx_get_ahb_gpu_registers(gpu,
                                a6xx_state, &a6xx_vbif_reglist,
                                &a6xx_state->registers[index++]);
+       if (!dumper) {
+               /*
+                * We can't use the crashdumper when the SMMU is stalled,
+                * because the GPU has no memory access until we resume
+                * translation (but we don't want to do that until after
+                * we have captured as much useful GPU state as possible).
+                * So instead collect registers via the CPU:
+                */
+               for (i = 0; i < ARRAY_SIZE(a6xx_reglist); i++)
+                       a6xx_get_ahb_gpu_registers(gpu,
+                               a6xx_state, &a6xx_reglist[i],
+                               &a6xx_state->registers[index++]);
+               return;
+       }
 
        for (i = 0; i < ARRAY_SIZE(a6xx_reglist); i++)
                a6xx_get_crashdumper_registers(gpu,
@@ -905,11 +919,13 @@ static void a6xx_get_indexed_registers(struct msm_gpu *gpu,
 
 struct msm_gpu_state *a6xx_gpu_state_get(struct msm_gpu *gpu)
 {
-       struct a6xx_crashdumper dumper = { 0 };
+       struct a6xx_crashdumper _dumper = { 0 }, *dumper = NULL;
        struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
        struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
        struct a6xx_gpu_state *a6xx_state = kzalloc(sizeof(*a6xx_state),
                GFP_KERNEL);
+       bool stalled = !!(gpu_read(gpu, REG_A6XX_RBBM_STATUS3) &
+                       A6XX_RBBM_STATUS3_SMMU_STALLED_ON_FAULT);
 
        if (!a6xx_state)
                return ERR_PTR(-ENOMEM);
@@ -928,14 +944,24 @@ struct msm_gpu_state *a6xx_gpu_state_get(struct msm_gpu *gpu)
        /* Get the banks of indexed registers */
        a6xx_get_indexed_registers(gpu, a6xx_state);
 
-       /* Try to initialize the crashdumper */
-       if (!a6xx_crashdumper_init(gpu, &dumper)) {
-               a6xx_get_registers(gpu, a6xx_state, &dumper);
-               a6xx_get_shaders(gpu, a6xx_state, &dumper);
-               a6xx_get_clusters(gpu, a6xx_state, &dumper);
-               a6xx_get_dbgahb_clusters(gpu, a6xx_state, &dumper);
+       /*
+        * Try to initialize the crashdumper, if we are not dumping state
+        * with the SMMU stalled.  The crashdumper needs memory access to
+        * write out GPU state, so we need to skip this when the SMMU is
+        * stalled in response to an iova fault
+        */
+       if (!stalled && !a6xx_crashdumper_init(gpu, &_dumper)) {
+               dumper = &_dumper;
+       }
+
+       a6xx_get_registers(gpu, a6xx_state, dumper);
+
+       if (dumper) {
+               a6xx_get_shaders(gpu, a6xx_state, dumper);
+               a6xx_get_clusters(gpu, a6xx_state, dumper);
+               a6xx_get_dbgahb_clusters(gpu, a6xx_state, dumper);
 
-               msm_gem_kernel_put(dumper.bo, gpu->aspace, true);
+               msm_gem_kernel_put(dumper->bo, gpu->aspace, true);
        }
 
        if (snapshot_debugbus)
index 90bc863..9f5a302 100644 (file)
@@ -684,6 +684,21 @@ void adreno_show(struct msm_gpu *gpu, struct msm_gpu_state *state,
                        adreno_gpu->info->revn, adreno_gpu->rev.core,
                        adreno_gpu->rev.major, adreno_gpu->rev.minor,
                        adreno_gpu->rev.patchid);
+       /*
+        * If this is state collected due to iova fault, so fault related info
+        *
+        * TTBR0 would not be zero, so this is a good way to distinguish
+        */
+       if (state->fault_info.ttbr0) {
+               const struct msm_gpu_fault_info *info = &state->fault_info;
+
+               drm_puts(p, "fault-info:\n");
+               drm_printf(p, "  - ttbr0=%.16llx\n", info->ttbr0);
+               drm_printf(p, "  - iova=%.16lx\n", info->iova);
+               drm_printf(p, "  - dir=%s\n", info->flags & IOMMU_FAULT_WRITE ? "WRITE" : "READ");
+               drm_printf(p, "  - type=%s\n", info->type);
+               drm_printf(p, "  - source=%s\n", info->block);
+       }
 
        drm_printf(p, "rbbm-status: 0x%08x\n", state->rbbm_status);
 
index 03e2cc2..405f841 100644 (file)
@@ -328,6 +328,7 @@ struct msm_gem_submit {
        struct dma_fence *fence;
        struct msm_gpu_submitqueue *queue;
        struct pid *pid;    /* submitting process */
+       bool fault_dumped;  /* Limit devcoredump dumping to one per submit */
        bool valid;         /* true if no cmdstream patching needed */
        bool in_rb;         /* "sudo" mode, copy cmds into RB */
        struct msm_ringbuffer *ring;
index 5480852..44f84bf 100644 (file)
@@ -50,6 +50,7 @@ static struct msm_gem_submit *submit_create(struct drm_device *dev,
        submit->cmd = (void *)&submit->bos[nr_bos];
        submit->queue = queue;
        submit->ring = gpu->rb[queue->prio];
+       submit->fault_dumped = false;
 
        /* initially, until copy_from_user() and bo lookup succeeds: */
        submit->nr_bos = 0;
index 4ee8ba0..0ebf7bc 100644 (file)
@@ -387,6 +387,7 @@ static void msm_gpu_crashstate_capture(struct msm_gpu *gpu,
        /* Fill in the additional crash state information */
        state->comm = kstrdup(comm, GFP_KERNEL);
        state->cmd = kstrdup(cmd, GFP_KERNEL);
+       state->fault_info = gpu->fault_info;
 
        if (submit) {
                int i, nr = 0;
@@ -559,6 +560,52 @@ static void recover_worker(struct kthread_work *work)
        msm_gpu_retire(gpu);
 }
 
+static void fault_worker(struct kthread_work *work)
+{
+       struct msm_gpu *gpu = container_of(work, struct msm_gpu, fault_work);
+       struct drm_device *dev = gpu->dev;
+       struct msm_gem_submit *submit;
+       struct msm_ringbuffer *cur_ring = gpu->funcs->active_ring(gpu);
+       char *comm = NULL, *cmd = NULL;
+
+       mutex_lock(&dev->struct_mutex);
+
+       submit = find_submit(cur_ring, cur_ring->memptrs->fence + 1);
+       if (submit && submit->fault_dumped)
+               goto resume_smmu;
+
+       if (submit) {
+               struct task_struct *task;
+
+               task = get_pid_task(submit->pid, PIDTYPE_PID);
+               if (task) {
+                       comm = kstrdup(task->comm, GFP_KERNEL);
+                       cmd = kstrdup_quotable_cmdline(task, GFP_KERNEL);
+                       put_task_struct(task);
+               }
+
+               /*
+                * When we get GPU iova faults, we can get 1000s of them,
+                * but we really only want to log the first one.
+                */
+               submit->fault_dumped = true;
+       }
+
+       /* Record the crash state */
+       pm_runtime_get_sync(&gpu->pdev->dev);
+       msm_gpu_crashstate_capture(gpu, submit, comm, cmd);
+       pm_runtime_put_sync(&gpu->pdev->dev);
+
+       kfree(cmd);
+       kfree(comm);
+
+resume_smmu:
+       memset(&gpu->fault_info, 0, sizeof(gpu->fault_info));
+       gpu->aspace->mmu->funcs->resume_translation(gpu->aspace->mmu);
+
+       mutex_unlock(&dev->struct_mutex);
+}
+
 static void hangcheck_timer_reset(struct msm_gpu *gpu)
 {
        struct msm_drm_private *priv = gpu->dev->dev_private;
@@ -923,6 +970,7 @@ int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev,
        INIT_LIST_HEAD(&gpu->active_list);
        kthread_init_work(&gpu->retire_work, retire_worker);
        kthread_init_work(&gpu->recover_work, recover_worker);
+       kthread_init_work(&gpu->fault_work, fault_worker);
 
        timer_setup(&gpu->hangcheck_timer, hangcheck_handler, 0);
 
index fdc5851..ef41ec0 100644 (file)
@@ -71,6 +71,15 @@ struct msm_gpu_funcs {
        uint32_t (*get_rptr)(struct msm_gpu *gpu, struct msm_ringbuffer *ring);
 };
 
+/* Additional state for iommu faults: */
+struct msm_gpu_fault_info {
+       u64 ttbr0;
+       unsigned long iova;
+       int flags;
+       const char *type;
+       const char *block;
+};
+
 struct msm_gpu {
        const char *name;
        struct drm_device *dev;
@@ -125,6 +134,12 @@ struct msm_gpu {
 #define DRM_MSM_HANGCHECK_DEFAULT_PERIOD 500 /* in ms */
        struct timer_list hangcheck_timer;
 
+       /* Fault info for most recent iova fault: */
+       struct msm_gpu_fault_info fault_info;
+
+       /* work for handling GPU ioval faults: */
+       struct kthread_work fault_work;
+
        /* work for handling GPU recovery: */
        struct kthread_work recover_work;
 
@@ -232,6 +247,8 @@ struct msm_gpu_state {
        char *comm;
        char *cmd;
 
+       struct msm_gpu_fault_info fault_info;
+
        int nr_bos;
        struct msm_gpu_state_bo *bos;
 };
index 3794961..f7d1945 100644 (file)
@@ -68,6 +68,10 @@ static int msm_gpummu_unmap(struct msm_mmu *mmu, uint64_t iova, size_t len)
        return 0;
 }
 
+static void msm_gpummu_resume_translation(struct msm_mmu *mmu)
+{
+}
+
 static void msm_gpummu_destroy(struct msm_mmu *mmu)
 {
        struct msm_gpummu *gpummu = to_msm_gpummu(mmu);
@@ -83,6 +87,7 @@ static const struct msm_mmu_funcs funcs = {
                .map = msm_gpummu_map,
                .unmap = msm_gpummu_unmap,
                .destroy = msm_gpummu_destroy,
+               .resume_translation = msm_gpummu_resume_translation,
 };
 
 struct msm_mmu *msm_gpummu_new(struct device *dev, struct msm_gpu *gpu)
index 6975b95..eed2a76 100644 (file)
@@ -184,6 +184,9 @@ struct msm_mmu *msm_iommu_pagetable_create(struct msm_mmu *parent)
         * the arm-smmu driver as a trigger to set up TTBR0
         */
        if (atomic_inc_return(&iommu->pagetables) == 1) {
+               /* Enable stall on iommu fault: */
+               adreno_smmu->set_stall(adreno_smmu->cookie, true);
+
                ret = adreno_smmu->set_ttbr0_cfg(adreno_smmu->cookie, &ttbr0_cfg);
                if (ret) {
                        free_io_pgtable_ops(pagetable->pgtbl_ops);
@@ -226,6 +229,13 @@ static int msm_fault_handler(struct iommu_domain *domain, struct device *dev,
        return 0;
 }
 
+static void msm_iommu_resume_translation(struct msm_mmu *mmu)
+{
+       struct adreno_smmu_priv *adreno_smmu = dev_get_drvdata(mmu->dev);
+
+       adreno_smmu->resume_translation(adreno_smmu->cookie, true);
+}
+
 static void msm_iommu_detach(struct msm_mmu *mmu)
 {
        struct msm_iommu *iommu = to_msm_iommu(mmu);
@@ -273,6 +283,7 @@ static const struct msm_mmu_funcs funcs = {
                .map = msm_iommu_map,
                .unmap = msm_iommu_unmap,
                .destroy = msm_iommu_destroy,
+               .resume_translation = msm_iommu_resume_translation,
 };
 
 struct msm_mmu *msm_iommu_new(struct device *dev, struct iommu_domain *domain)
index a88f44c..de158e1 100644 (file)
@@ -15,6 +15,7 @@ struct msm_mmu_funcs {
                        size_t len, int prot);
        int (*unmap)(struct msm_mmu *mmu, uint64_t iova, size_t len);
        void (*destroy)(struct msm_mmu *mmu);
+       void (*resume_translation)(struct msm_mmu *mmu);
 };
 
 enum msm_mmu_type {