drm/msm: split rd debugfs file

Split into two instances, the existing $debugfs/rd which continues to
dump all submits, and $debugfs/hangrd which will be used to dump just
submits that cause gpu hangs (and eventually faults, but that will
require some iommu framework enhancements).

Signed-off-by: Rob Clark <robdclark@gmail.com>

diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index 666fce6..b01bd7f 100644 (file)
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -108,7 +108,8 @@ struct msm_drm_private {
 
        struct drm_fb_helper *fbdev;
 
-       struct msm_rd_state *rd;
+       struct msm_rd_state *rd;       /* debugfs to dump all submits */
+       struct msm_rd_state *hangrd;   /* debugfs to dump hanging submits */
        struct msm_perf_state *perf;
 
        /* list of GEM objects: */
@@ -298,7 +299,7 @@ void msm_framebuffer_describe(struct drm_framebuffer *fb, struct seq_file *m);
 int msm_debugfs_late_init(struct drm_device *dev);
 int msm_rd_debugfs_init(struct drm_minor *minor);
 void msm_rd_debugfs_cleanup(struct msm_drm_private *priv);
-void msm_rd_dump_submit(struct msm_gem_submit *submit);
+void msm_rd_dump_submit(struct msm_rd_state *rd, struct msm_gem_submit *submit);
 int msm_perf_debugfs_init(struct drm_minor *minor);
 void msm_perf_debugfs_cleanup(struct msm_drm_private *priv);
 #else

diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index 8481014..7fc6f68 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -557,7 +557,7 @@ void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit,
 
        list_add_tail(&submit->node, &ring->submits);
 
-       msm_rd_dump_submit(submit);
+       msm_rd_dump_submit(priv->rd, submit);
 
        update_sw_cntrs(gpu);
 

diff --git a/drivers/gpu/drm/msm/msm_rd.c b/drivers/gpu/drm/msm/msm_rd.c
index 47c0c78..0fac6ea 100644 (file)
--- a/drivers/gpu/drm/msm/msm_rd.c
+++ b/drivers/gpu/drm/msm/msm_rd.c
@@ -19,11 +19,17 @@
  *
  *   tail -f /sys/kernel/debug/dri/<minor>/rd > logfile.rd
  *
- * To log the cmdstream in a format that is understood by freedreno/cffdump
+ * to log the cmdstream in a format that is understood by freedreno/cffdump
  * utility.  By comparing the last successfully completed fence #, to the
  * cmdstream for the next fence, you can narrow down which process and submit
  * caused the gpu crash/lockup.
  *
+ * Additionally:
+ *
+ *   tail -f /sys/kernel/debug/dri/<minor>/hangrd > logfile.rd
+ *
+ * will capture just the cmdstream from submits which triggered a GPU hang.
+ *
  * This bypasses drm_debugfs_create_files() mainly because we need to use
  * our own fops for a bit more control.  In particular, we don't want to
  * do anything if userspace doesn't have the debugfs file open.
@@ -212,53 +218,89 @@ static const struct file_operations rd_debugfs_fops = {
        .release = rd_release,
 };
 
-int msm_rd_debugfs_init(struct drm_minor *minor)
+
+static void rd_cleanup(struct msm_rd_state *rd)
+{
+       if (!rd)
+               return;
+
+       mutex_destroy(&rd->read_lock);
+       kfree(rd);
+}
+
+static struct msm_rd_state *rd_init(struct drm_minor *minor, const char *name)
 {
-       struct msm_drm_private *priv = minor->dev->dev_private;
        struct msm_rd_state *rd;
        struct dentry *ent;
-
-       /* only create on first minor: */
-       if (priv->rd)
-               return 0;
+       int ret = 0;
 
        rd = kzalloc(sizeof(*rd), GFP_KERNEL);
        if (!rd)
-               return -ENOMEM;
+               return ERR_PTR(-ENOMEM);
 
        rd->dev = minor->dev;
        rd->fifo.buf = rd->buf;
 
        mutex_init(&rd->read_lock);
-       priv->rd = rd;
 
        init_waitqueue_head(&rd->fifo_event);
 
-       ent = debugfs_create_file("rd", S_IFREG | S_IRUGO,
+       ent = debugfs_create_file(name, S_IFREG | S_IRUGO,
                        minor->debugfs_root, rd, &rd_debugfs_fops);
        if (!ent) {
-               DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/rd\n",
-                               minor->debugfs_root);
+               DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/%s\n",
+                               minor->debugfs_root, name);
+               ret = -ENOMEM;
                goto fail;
        }
 
+       return rd;
+
+fail:
+       rd_cleanup(rd);
+       return ERR_PTR(ret);
+}
+
+int msm_rd_debugfs_init(struct drm_minor *minor)
+{
+       struct msm_drm_private *priv = minor->dev->dev_private;
+       struct msm_rd_state *rd;
+       int ret;
+
+       /* only create on first minor: */
+       if (priv->rd)
+               return 0;
+
+       rd = rd_init(minor, "rd");
+       if (IS_ERR(rd)) {
+               ret = PTR_ERR(rd);
+               goto fail;
+       }
+
+       priv->rd = rd;
+
+       rd = rd_init(minor, "hangrd");
+       if (IS_ERR(rd)) {
+               ret = PTR_ERR(rd);
+               goto fail;
+       }
+
+       priv->hangrd = rd;
+
        return 0;
 
 fail:
        msm_rd_debugfs_cleanup(priv);
-       return -1;
+       return ret;
 }
 
 void msm_rd_debugfs_cleanup(struct msm_drm_private *priv)
 {
-       struct msm_rd_state *rd = priv->rd;
-
-       if (!rd)
-               return;
-
+       rd_cleanup(priv->rd);
        priv->rd = NULL;
-       mutex_destroy(&rd->read_lock);
-       kfree(rd);
+
+       rd_cleanup(priv->hangrd);
+       priv->hangrd = NULL;
 }
 
 static void snapshot_buf(struct msm_rd_state *rd,
@@ -296,11 +338,10 @@ static void snapshot_buf(struct msm_rd_state *rd,
 }
 
 /* called under struct_mutex */
-void msm_rd_dump_submit(struct msm_gem_submit *submit)
+void msm_rd_dump_submit(struct msm_rd_state *rd, struct msm_gem_submit *submit)
 {
        struct drm_device *dev = submit->dev;
-       struct msm_drm_private *priv = dev->dev_private;
-       struct msm_rd_state *rd = priv->rd;
+       struct task_struct *task;
        char msg[128];
        int i, n;
 
@@ -312,9 +353,17 @@ void msm_rd_dump_submit(struct msm_gem_submit *submit)
         */
        WARN_ON(!mutex_is_locked(&dev->struct_mutex));
 
-       n = snprintf(msg, sizeof(msg), "%.*s/%d: fence=%u",
-                       TASK_COMM_LEN, current->comm, task_pid_nr(current),
-                       submit->fence->seqno);
+       rcu_read_lock();
+       task = pid_task(submit->pid, PIDTYPE_PID);
+       if (task) {
+               n = snprintf(msg, sizeof(msg), "%.*s/%d: fence=%u",
+                               TASK_COMM_LEN, task->comm,
+                               pid_nr(submit->pid), submit->seqno);
+       } else {
+               n = snprintf(msg, sizeof(msg), "???/%d: fence=%u",
+                               pid_nr(submit->pid), submit->seqno);
+       }
+       rcu_read_unlock();
 
        rd_write_section(rd, RD_CMD, msg, ALIGN(n, 4));