[PATCH] drm/amdgpu: Add autodump debugfs node for gpu reset v3

Christian König ckoenig.leichtzumerken at gmail.com
Fri Apr 24 11:47:34 UTC 2020


From: Jiange Zhao <Jiange.Zhao at amd.com>

When GPU got timeout, it would notify an interested part
of an opportunity to dump info before actual GPU reset.

A usermode app would open 'autodump' node under debugfs system
and poll() for readable/writable. When a GPU reset is due,
amdgpu would notify usermode app through wait_queue_head and give
it 10 minutes to dump info.

After usermode app has done its work, this 'autodump' node is closed.
On node closure, amdgpu gets to know the dump is done through
the completion that is triggered in release().

There is no write or read callback because necessary info can be
obtained through dmesg and umr. Messages back and forth between
usermode app and amdgpu are unnecessary.

v2: (1) changed 'registered' to 'app_listening'
    (2) add a mutex in open() to prevent race condition

v3 (chk): grab the reset lock to avoid race in autodump_open,
	  rename debugfs file to amdgpu_autodump,
	  provide autodump_read as well,
	  style and code cleanups

Signed-off-by: Jiange Zhao <Jiange.Zhao at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h         |  2 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 92 ++++++++++++++++++++-
 drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h |  6 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c  |  2 +
 4 files changed, 101 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index bc1e0fd71a09..6f8ef98c4b97 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -990,6 +990,8 @@ struct amdgpu_device {
 	char				product_number[16];
 	char				product_name[32];
 	char				serial[16];
+
+	struct amdgpu_autodump		autodump;
 };
 
 static inline struct amdgpu_device *amdgpu_ttm_adev(struct ttm_bo_device *bdev)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
index 1a4894fa3693..b1029d12a971 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
@@ -27,7 +27,7 @@
 #include <linux/pci.h>
 #include <linux/uaccess.h>
 #include <linux/pm_runtime.h>
-
+#include <linux/poll.h>
 #include <drm/drm_debugfs.h>
 
 #include "amdgpu.h"
@@ -74,8 +74,96 @@ int amdgpu_debugfs_add_files(struct amdgpu_device *adev,
 	return 0;
 }
 
+int amdgpu_debugfs_wait_dump(struct amdgpu_device *adev)
+{
+#if defined(CONFIG_DEBUG_FS)
+	const unsigned long timeout = 600 * HZ;
+	int ret;
+
+	wake_up_interruptible(&adev->autodump.gpu_hang);
+
+	ret = wait_for_completion_interruptible_timeout(&adev->autodump.dumping,
+							timeout);
+	if (ret == 0) {
+		pr_err("autodump: timeout, move on to gpu recovery\n");
+		return -ETIMEDOUT;
+	}
+#endif
+	return 0;
+}
+
 #if defined(CONFIG_DEBUG_FS)
 
+static int amdgpu_debugfs_autodump_open(struct inode *inode, struct file *file)
+{
+	struct amdgpu_device *adev = inode->i_private;
+	int ret;
+
+	file->private_data = adev;
+
+	mutex_lock(&adev->lock_reset);
+	if (adev->autodump.dumping.done) {
+		reinit_completion(&adev->autodump.dumping);
+		ret = 0;
+	} else {
+		ret = -EBUSY;
+	}
+	mutex_unlock(&adev->lock_reset);
+
+	return ret;
+}
+
+static int amdgpu_debugfs_autodump_release(struct inode *inode,
+					   struct file *file)
+{
+	struct amdgpu_device *adev = file->private_data;
+
+	complete(&adev->autodump.dumping);
+	return 0;
+}
+
+static ssize_t amdgpu_debugfs_autodump_read(struct file *file, char __user *buf,
+					    size_t size, loff_t *pos)
+{
+	struct amdgpu_device *adev = file->private_data;
+
+	wait_event_interruptible(adev->autodump.gpu_hang, adev->in_gpu_reset);
+	return 0;
+}
+
+unsigned int amdgpu_debugfs_autodump_poll(struct file *file,
+					  struct poll_table_struct *poll_table)
+{
+	struct amdgpu_device *adev = file->private_data;
+
+	poll_wait(file, &adev->autodump.gpu_hang, poll_table);
+
+	if (adev->in_gpu_reset)
+		return POLLIN | POLLRDNORM | POLLWRNORM;
+
+	return 0;
+}
+
+static const struct file_operations autodump_debug_fops = {
+	.owner = THIS_MODULE,
+	.open = amdgpu_debugfs_autodump_open,
+	.read = amdgpu_debugfs_autodump_read,
+	.poll = amdgpu_debugfs_autodump_poll,
+	.release = amdgpu_debugfs_autodump_release,
+};
+
+static void amdgpu_debugfs_autodump_init(struct amdgpu_device *adev)
+{
+	init_completion(&adev->autodump.dumping);
+	init_waitqueue_head(&adev->autodump.gpu_hang);
+
+	complete(&adev->autodump.dumping);
+
+	debugfs_create_file("amdgpu_autodump", 0600,
+			    adev->ddev->primary->debugfs_root,
+			    adev, &autodump_debug_fops);
+}
+
 /**
  * amdgpu_debugfs_process_reg_op - Handle MMIO register reads/writes
  *
@@ -1434,6 +1522,8 @@ int amdgpu_debugfs_init(struct amdgpu_device *adev)
 
 	amdgpu_ras_debugfs_create_all(adev);
 
+	amdgpu_debugfs_autodump_init(adev);
+
 	return amdgpu_debugfs_add_files(adev, amdgpu_debugfs_list,
 					ARRAY_SIZE(amdgpu_debugfs_list));
 }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
index de12d1101526..3504c48e1564 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.h
@@ -31,6 +31,11 @@ struct amdgpu_debugfs {
 	unsigned		num_files;
 };
 
+struct amdgpu_autodump {
+	struct completion	dumping;
+	struct wait_queue_head	gpu_hang;
+};
+
 int amdgpu_debugfs_regs_init(struct amdgpu_device *adev);
 int amdgpu_debugfs_init(struct amdgpu_device *adev);
 void amdgpu_debugfs_fini(struct amdgpu_device *adev);
@@ -40,3 +45,4 @@ int amdgpu_debugfs_add_files(struct amdgpu_device *adev,
 int amdgpu_debugfs_fence_init(struct amdgpu_device *adev);
 int amdgpu_debugfs_firmware_init(struct amdgpu_device *adev);
 int amdgpu_debugfs_gem_init(struct amdgpu_device *adev);
+int amdgpu_debugfs_wait_dump(struct amdgpu_device *adev);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 3d601d5dd5af..44e54ea7af0f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3915,6 +3915,8 @@ static int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev,
 	int i, r = 0;
 	bool need_full_reset  = *need_full_reset_arg;
 
+	amdgpu_debugfs_wait_dump(adev);
+
 	/* block all schedulers and reset given job's ring */
 	for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
 		struct amdgpu_ring *ring = adev->rings[i];
-- 
2.17.1



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