1// SPDX-License-Identifier: GPL-2.0
2/*
3 * IOMMU debugfs core infrastructure
4 *
5 * Copyright (C) 2018 Advanced Micro Devices, Inc.
6 *
7 * Author: Gary R Hook <gary.hook@amd.com>
8 */
9
10#include <linux/pci.h>
11#include <linux/iommu.h>
12#include <linux/debugfs.h>
13
14struct dentry *iommu_debugfs_dir;
15EXPORT_SYMBOL_GPL(iommu_debugfs_dir);
16
17/**
18 * iommu_debugfs_setup - create the top-level iommu directory in debugfs
19 *
20 * Provide base enablement for using debugfs to expose internal data of an
21 * IOMMU driver. When called, this function creates the
22 * /sys/kernel/debug/iommu directory.
23 *
24 * Emit a strong warning at boot time to indicate that this feature is
25 * enabled.
26 *
27 * This function is called from iommu_init; drivers may then use
28 * iommu_debugfs_dir to instantiate a vendor-specific directory to be used
29 * to expose internal data.
30 */
31void iommu_debugfs_setup(void)
32{
33	if (!iommu_debugfs_dir) {
34		iommu_debugfs_dir = debugfs_create_dir("iommu", NULL);
35		pr_warn("\n");
36		pr_warn("*************************************************************\n");
37		pr_warn("**     NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE    **\n");
38		pr_warn("**                                                         **\n");
39		pr_warn("**  IOMMU DebugFS SUPPORT HAS BEEN ENABLED IN THIS KERNEL  **\n");
40		pr_warn("**                                                         **\n");
41		pr_warn("** This means that this kernel is built to expose internal **\n");
42		pr_warn("** IOMMU data structures, which may compromise security on **\n");
43		pr_warn("** your system.                                            **\n");
44		pr_warn("**                                                         **\n");
45		pr_warn("** If you see this message and you are not debugging the   **\n");
46		pr_warn("** kernel, report this immediately to your vendor!         **\n");
47		pr_warn("**                                                         **\n");
48		pr_warn("**     NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE    **\n");
49		pr_warn("*************************************************************\n");
50	}
51}
52