[PATCH 15/15] drm/xe: Add xe_client_debugfs and introduce debug_data file

[Mika Kuoppala]

From: Christoph Manszewski <christoph.manszewski at intel.com>

Create a debug_data file for each xe file/client which is supposed to
list all mapped debug data and attempts to mimic '/proc/pid/maps'.
Each line represents a single mapping and has the following format:

  <vm id> <begin>-<end> <flags> <offset> <pathname>

Signed-off-by: Christoph Manszewski <christoph.manszewski at intel.com>
---
 drivers/gpu/drm/xe/Makefile            |   3 +-
 drivers/gpu/drm/xe/xe_client_debugfs.c | 118 +++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_client_debugfs.h |  19 ++++
 drivers/gpu/drm/xe/xe_device.c         |   3 +
 4 files changed, 142 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/xe/xe_client_debugfs.c
 create mode 100644 drivers/gpu/drm/xe/xe_client_debugfs.h

diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
index b932a9e70284..c1d8068d2a97 100644
--- a/drivers/gpu/drm/xe/Makefile
+++ b/drivers/gpu/drm/xe/Makefile
@@ -319,7 +319,8 @@ ifeq ($(CONFIG_DRM_FBDEV_EMULATION),y)
 endif
 
 ifeq ($(CONFIG_DEBUG_FS),y)
-	xe-y += xe_debugfs.o \
+	xe-y += xe_client_debugfs.o \
+		xe_debugfs.o \
 		xe_gt_debugfs.o \
 		xe_gt_sriov_vf_debugfs.o \
 		xe_gt_stats.o \
diff --git a/drivers/gpu/drm/xe/xe_client_debugfs.c b/drivers/gpu/drm/xe/xe_client_debugfs.c
new file mode 100644
index 000000000000..0b952038e698
--- /dev/null
+++ b/drivers/gpu/drm/xe/xe_client_debugfs.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#include "xe_client_debugfs.h"
+
+#include <linux/debugfs.h>
+
+#include "xe_debug_data.h"
+#include "xe_debug_data_types.h"
+#include "xe_device_types.h"
+#include "xe_vm_types.h"
+
+#define MAX_LINE_LEN (64 + PATH_MAX)
+
+static ssize_t debug_data_read(struct file *file, char __user *buf, size_t count,
+			       loff_t *ppos)
+{
+	struct xe_debug_data *dd;
+	unsigned long vm_index;
+	const char *path;
+	char *kbuf;
+	struct xe_vm *vm;
+
+	struct xe_file *xef = file->private_data;
+	ssize_t total = 0;
+	loff_t pos = 0;
+
+	if (!xef || !buf)
+		return -EINVAL;
+
+	kbuf = kmalloc(MAX_LINE_LEN, GFP_KERNEL);
+	if (!kbuf)
+		return -ENOMEM;
+
+	mutex_lock(&xef->vm.lock);
+
+	xa_for_each(&xef->vm.xa, vm_index, vm) {
+		mutex_lock(&vm->debug_data.lock);
+		list_for_each_entry(dd, &vm->debug_data.list, link) {
+			int len;
+
+			path = dd->flags & DRM_XE_VM_BIND_DEBUG_DATA_FLAG_PSEUDO ?
+				xe_debug_data_pseudo_path_to_string(dd->pseudopath) :
+				dd->pathname;
+
+			/* Format: <vm id> <begin>-<end> <flags> <offset> <pathname> */
+			len = snprintf(kbuf, MAX_LINE_LEN, "%lu 0x%llx-0x%llx 0x%llx 0x%x\t%s\n",
+				vm_index,
+				dd->addr,
+				dd->addr + dd->range,
+				dd->flags,
+				dd->offset,
+				path);
+
+			if (pos + len <= *ppos) {
+				pos += len;
+				continue;
+			}
+
+			if (pos < *ppos) {
+				const int skip = *ppos - pos;
+
+				len -= skip;
+				memmove(kbuf, kbuf + skip, len);
+				pos = *ppos;
+			}
+
+			if (total + len > count)
+				len = count - total;
+
+			if (copy_to_user(buf + total, kbuf, len)) {
+				mutex_unlock(&vm->debug_data.lock);
+				mutex_unlock(&xef->vm.lock);
+				kfree(kbuf);
+				return -EFAULT;
+			}
+
+			total += len;
+			pos += len;
+
+			if (total >= count) {
+				mutex_unlock(&vm->debug_data.lock);
+				mutex_unlock(&xef->vm.lock);
+				kfree(kbuf);
+				*ppos = pos;
+				return total;
+			}
+		}
+		mutex_unlock(&vm->debug_data.lock);
+	}
+
+	mutex_unlock(&xef->vm.lock);
+	kfree(kbuf);
+	*ppos = pos;
+	return total;
+}
+
+static int debug_data_open(struct inode *inode, struct file *file)
+{
+	struct xe_file *xef = inode->i_private;
+
+	file->private_data = xef;
+	return 0;
+}
+
+static const struct file_operations maps_fops = {
+	.owner = THIS_MODULE,
+	.open = debug_data_open,
+	.read = debug_data_read,
+	.llseek = default_llseek,
+};
+
+void xe_client_debugfs_register(struct xe_file *xef)
+{
+	debugfs_create_file("debug_data", 0444, xef->drm->debugfs_client, xef, &maps_fops);
+}
diff --git a/drivers/gpu/drm/xe/xe_client_debugfs.h b/drivers/gpu/drm/xe/xe_client_debugfs.h
new file mode 100644
index 000000000000..9eace15c0a49
--- /dev/null
+++ b/drivers/gpu/drm/xe/xe_client_debugfs.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#ifndef _XE_CLIENT_DEBUGFS_H_
+#define _XE_CLIENT_DEBUGFS_H_
+
+#include <linux/debugfs.h>
+
+struct xe_file;
+
+#ifdef CONFIG_DEBUG_FS
+void xe_client_debugfs_register(struct xe_file *xef);
+#else
+static inline void xe_client_debugfs_register(struct xe_file *xef) { }
+#endif
+
+#endif // _XE_CLIENT_DEBUGFS_H_
diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 0249fb4aa966..af9c98a4f3a3 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -24,6 +24,7 @@
 #include "regs/xe_regs.h"
 #include "xe_bo.h"
 #include "xe_bo_evict.h"
+#include "xe_client_debugfs.h"
 #include "xe_debugfs.h"
 #include "xe_devcoredump.h"
 #include "xe_device_sysfs.h"
@@ -117,6 +118,8 @@ static int xe_file_open(struct drm_device *dev, struct drm_file *file)
 		put_task_struct(task);
 	}
 
+	xe_client_debugfs_register(xef);
+
 	return 0;
 }
 
-- 
2.43.0