drm/i915: Copy user requested buffers into the error state

Introduce a new execobject.flag (EXEC_OBJECT_CAPTURE) that userspace may
use to indicate that it wants the contents of this buffer preserved in
the error state (/sys/class/drm/cardN/error) following a GPU hang
involving this batch.

Use this at your discretion, the contents of the error state. although
compressed, are allocated with GFP_ATOMIC (i.e. limited) and kept for all
eternity (until the error state is destroyed).

Based on an earlier patch by Ben Widawsky <ben@bwidawsk.net>
Testcase: igt/gem_exec_capture
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Matt Turner <mattst88@gmail.com>
Acked-by: Ben Widawsky <ben@bwidawsk.net>
Acked-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170415093902.22581-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index bd85e3826b72b318987d03ff9cebbbeff3480f33..cc7393e65e9959d66d22441397800d490d40e716 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -350,6 +350,7 @@ static int i915_getparam(struct drm_device *dev, void *data,
        case I915_PARAM_HAS_EXEC_SOFTPIN:
        case I915_PARAM_HAS_EXEC_ASYNC:
        case I915_PARAM_HAS_EXEC_FENCE:
+       case I915_PARAM_HAS_EXEC_CAPTURE:
                /* For the time being all of these are always true;
                 * if some supported hardware does not have one of these
                 * features this value needs to be provided from

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1af4e6f5410ceeefc3dcc75ea28f5c883a60f925..ed21f0afaaec790756f24bb745f77050b403f986 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1025,6 +1025,9 @@ struct i915_gpu_state {
                        u32 *pages[0];
                } *ringbuffer, *batchbuffer, *wa_batchbuffer, *ctx, *hws_page;
 
+               struct drm_i915_error_object **user_bo;
+               long user_bo_count;
+
                struct drm_i915_error_object *wa_ctx;
 
                struct drm_i915_error_request {

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index a3e59c8ef27baf4f3584ff5016635d8005735af6..af1965774e7b7f4408c75e39081097e60b483d3a 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1114,6 +1114,18 @@ i915_gem_execbuffer_move_to_gpu(struct drm_i915_gem_request *req,
        list_for_each_entry(vma, vmas, exec_list) {
                struct drm_i915_gem_object *obj = vma->obj;
 
+               if (vma->exec_entry->flags & EXEC_OBJECT_CAPTURE) {
+                       struct i915_gem_capture_list *capture;
+
+                       capture = kmalloc(sizeof(*capture), GFP_KERNEL);
+                       if (unlikely(!capture))
+                               return -ENOMEM;
+
+                       capture->next = req->capture_list;
+                       capture->vma = vma;
+                       req->capture_list = capture;
+               }
+
                if (vma->exec_entry->flags & EXEC_OBJECT_ASYNC)
                        continue;
 

diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index 313cdff7c6dd6e92d62179f6c751378afe8ca7d0..095cccc2e8b27e6bf4c5778db048bf297508ca30 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -292,6 +292,19 @@ static void advance_ring(struct drm_i915_gem_request *request)
        request->ring->head = tail;
 }
 
+static void free_capture_list(struct drm_i915_gem_request *request)
+{
+       struct i915_gem_capture_list *capture;
+
+       capture = request->capture_list;
+       while (capture) {
+               struct i915_gem_capture_list *next = capture->next;
+
+               kfree(capture);
+               capture = next;
+       }
+}
+
 static void i915_gem_request_retire(struct drm_i915_gem_request *request)
 {
        struct intel_engine_cs *engine = request->engine;
@@ -317,6 +330,8 @@ static void i915_gem_request_retire(struct drm_i915_gem_request *request)
        unreserve_seqno(request->engine);
        advance_ring(request);
 
+       free_capture_list(request);
+
        /* Walk through the active list, calling retire on each. This allows
         * objects to track their GPU activity and mark themselves as idle
         * when their *last* active request is completed (updating state
@@ -615,6 +630,7 @@ i915_gem_request_alloc(struct intel_engine_cs *engine,
        req->global_seqno = 0;
        req->file_priv = NULL;
        req->batch = NULL;
+       req->capture_list = NULL;
 
        /*
         * Reserve space in the ring buffer for all the commands required to

diff --git a/drivers/gpu/drm/i915/i915_gem_request.h b/drivers/gpu/drm/i915/i915_gem_request.h
index a211c53c813f75d9e38274643bfc73031eeafa5a..4ccab5affd3c22bdc4e6c7890b0df6f5636ac86d 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_request.h
+++ b/drivers/gpu/drm/i915/i915_gem_request.h
@@ -73,6 +73,11 @@ struct i915_priotree {
 #define I915_PRIORITY_MIN (-I915_PRIORITY_MAX)
 };
 
+struct i915_gem_capture_list {
+       struct i915_gem_capture_list *next;
+       struct i915_vma *vma;
+};
+
 /**
  * Request queue structure.
  *
@@ -167,6 +172,12 @@ struct drm_i915_gem_request {
         * error state dump only).
         */
        struct i915_vma *batch;
+       /** Additional buffers requested by userspace to be captured upon
+        * a GPU hang. The vma/obj on this list are protected by their
+        * active reference - all objects on this list must also be
+        * on the active_list (of their final request).
+        */
+       struct i915_gem_capture_list *capture_list;
        struct list_head active_list;
 
        /** Time at which this request was emitted, in jiffies. */

diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index 8effc59f5cb572651bd7f98fba747821bef0dcc8..4b247b050dcd9e019e3ea8c4e561ef11ed6d4a79 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -712,6 +712,10 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
                        print_error_obj(m, dev_priv->engine[i], NULL, obj);
                }
 
+               for (j = 0; j < ee->user_bo_count; j++)
+                       print_error_obj(m, dev_priv->engine[i],
+                                       "user", ee->user_bo[j]);
+
                if (ee->num_requests) {
                        err_printf(m, "%s --- %d requests\n",
                                   dev_priv->engine[i]->name,
@@ -825,11 +829,15 @@ void __i915_gpu_state_free(struct kref *error_ref)
 {
        struct i915_gpu_state *error =
                container_of(error_ref, typeof(*error), ref);
-       int i;
+       long i, j;
 
        for (i = 0; i < ARRAY_SIZE(error->engine); i++) {
                struct drm_i915_error_engine *ee = &error->engine[i];
 
+               for (j = 0; j < ee->user_bo_count; j++)
+                       i915_error_object_free(ee->user_bo[j]);
+               kfree(ee->user_bo);
+
                i915_error_object_free(ee->batchbuffer);
                i915_error_object_free(ee->wa_batchbuffer);
                i915_error_object_free(ee->ringbuffer);
@@ -1346,6 +1354,35 @@ static void record_context(struct drm_i915_error_context *e,
        e->active = ctx->active_count;
 }
 
+static void request_record_user_bo(struct drm_i915_gem_request *request,
+                                  struct drm_i915_error_engine *ee)
+{
+       struct i915_gem_capture_list *c;
+       struct drm_i915_error_object **bo;
+       long count;
+
+       count = 0;
+       for (c = request->capture_list; c; c = c->next)
+               count++;
+
+       bo = NULL;
+       if (count)
+               bo = kcalloc(count, sizeof(*bo), GFP_ATOMIC);
+       if (!bo)
+               return;
+
+       count = 0;
+       for (c = request->capture_list; c; c = c->next) {
+               bo[count] = i915_error_object_create(request->i915, c->vma);
+               if (!bo[count])
+                       break;
+               count++;
+       }
+
+       ee->user_bo = bo;
+       ee->user_bo_count = count;
+}
+
 static void i915_gem_record_rings(struct drm_i915_private *dev_priv,
                                  struct i915_gpu_state *error)
 {
@@ -1392,6 +1429,7 @@ static void i915_gem_record_rings(struct drm_i915_private *dev_priv,
                                ee->wa_batchbuffer =
                                        i915_error_object_create(dev_priv,
                                                                 engine->scratch);
+                       request_record_user_bo(request, ee);
 
                        ee->ctx =
                                i915_error_object_create(dev_priv,

diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 9ee06ec8a2d6b430deead76159a5adfd0bf62cc4..f24a80d2d42e0ebe9cb5d033706521430325b318 100644 (file)
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -412,6 +412,12 @@ typedef struct drm_i915_irq_wait {
  */
 #define I915_PARAM_HAS_EXEC_FENCE       44
 
+/* Query whether DRM_I915_GEM_EXECBUFFER2 supports the ability to capture
+ * user specified bufffers for post-mortem debugging of GPU hangs. See
+ * EXEC_OBJECT_CAPTURE.
+ */
+#define I915_PARAM_HAS_EXEC_CAPTURE     45
+
 typedef struct drm_i915_getparam {
        __s32 param;
        /*
@@ -775,8 +781,15 @@ struct drm_i915_gem_exec_object2 {
  * I915_PARAM_HAS_EXEC_FENCE to order execbufs and execute them asynchronously.
  */
 #define EXEC_OBJECT_ASYNC              (1<<6)
+/* Request that the contents of this execobject be copied into the error
+ * state upon a GPU hang involving this batch for post-mortem debugging.
+ * These buffers are recorded in no particular order as "user" in
+ * /sys/class/drm/cardN/error. Query I915_PARAM_HAS_EXEC_CAPTURE to see
+ * if the kernel supports this flag.
+ */
+#define EXEC_OBJECT_CAPTURE            (1<<7)
 /* All remaining bits are MBZ and RESERVED FOR FUTURE USE */
-#define __EXEC_OBJECT_UNKNOWN_FLAGS -(EXEC_OBJECT_ASYNC<<1)
+#define __EXEC_OBJECT_UNKNOWN_FLAGS -(EXEC_OBJECT_CAPTURE<<1)
        __u64 flags;
 
        union {