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Provide base enablement for using debugfs to expose internal data of an IOMMU driver. When called, create the /sys/kernel/debug/iommu directory. Emit a strong warning at boot time to indicate that this feature is enabled. This function is called from iommu_init, and creates the initial DebugFS directory. Drivers may then call iommu_debugfs_new_driver_dir() to instantiate a device-specific directory to expose internal data. It will return a pointer to the new dentry structure created in /sys/kernel/debug/iommu, or NULL in the event of a failure. Since the IOMMU driver can not be removed from the running system, there is no need for an "off" function. Signed-off-by: Gary R Hook <gary.hook@amd.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
66 lines
2.5 KiB
C
66 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* IOMMU debugfs core infrastructure
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*
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* Copyright (C) 2018 Advanced Micro Devices, Inc.
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*
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* Author: Gary R Hook <gary.hook@amd.com>
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*/
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#include <linux/pci.h>
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#include <linux/iommu.h>
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#include <linux/debugfs.h>
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struct dentry *iommu_debugfs_dir;
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/**
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* iommu_debugfs_setup - create the top-level iommu directory in debugfs
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*
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* Provide base enablement for using debugfs to expose internal data of an
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* IOMMU driver. When called, this function creates the
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* /sys/kernel/debug/iommu directory.
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*
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* Emit a strong warning at boot time to indicate that this feature is
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* enabled.
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*
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* This function is called from iommu_init; drivers may then call
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* iommu_debugfs_new_driver_dir() to instantiate a vendor-specific
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* directory to be used to expose internal data.
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*/
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void iommu_debugfs_setup(void)
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{
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if (!iommu_debugfs_dir) {
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iommu_debugfs_dir = debugfs_create_dir("iommu", NULL);
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pr_warn("\n");
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pr_warn("*************************************************************\n");
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pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
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pr_warn("** **\n");
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pr_warn("** IOMMU DebugFS SUPPORT HAS BEEN ENABLED IN THIS KERNEL **\n");
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pr_warn("** **\n");
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pr_warn("** This means that this kernel is built to expose internal **\n");
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pr_warn("** IOMMU data structures, which may compromise security on **\n");
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pr_warn("** your system. **\n");
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pr_warn("** **\n");
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pr_warn("** If you see this message and you are not debugging the **\n");
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pr_warn("** kernel, report this immediately to your vendor! **\n");
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pr_warn("** **\n");
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pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
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pr_warn("*************************************************************\n");
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}
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}
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/**
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* iommu_debugfs_new_driver_dir - create a vendor directory under debugfs/iommu
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* @vendor: name of the vendor-specific subdirectory to create
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*
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* This function is called by an IOMMU driver to create the top-level debugfs
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* directory for that driver.
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*
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* Return: upon success, a pointer to the dentry for the new directory.
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* NULL in case of failure.
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*/
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struct dentry *iommu_debugfs_new_driver_dir(const char *vendor)
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{
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return debugfs_create_dir(vendor, iommu_debugfs_dir);
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}
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EXPORT_SYMBOL_GPL(iommu_debugfs_new_driver_dir);
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