LXR linux/drivers/iommu/iommu-debugfs.c

   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