diff options
author | Gary R Hook <gary.hook@amd.com> | 2018-06-12 16:41:21 -0500 |
---|---|---|
committer | Joerg Roedel <jroedel@suse.de> | 2018-07-06 14:06:30 +0200 |
commit | bad614b24293ae463e74d2465685f0e4e229baca (patch) | |
tree | 5548eef5b84284b0621f60ffdde93c75e92a6241 /drivers | |
parent | 021c91791a5e7e85c567452f1be3e4c2c6cb6063 (diff) |
iommu: Enable debugfs exposure of IOMMU driver internals
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>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/iommu/Kconfig | 10 | ||||
-rw-r--r-- | drivers/iommu/Makefile | 1 | ||||
-rw-r--r-- | drivers/iommu/iommu-debugfs.c | 66 | ||||
-rw-r--r-- | drivers/iommu/iommu.c | 2 |
4 files changed, 79 insertions, 0 deletions
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index e055d228bfb9..ab9181d8af3b 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -60,6 +60,16 @@ config IOMMU_IO_PGTABLE_ARMV7S_SELFTEST endmenu +config IOMMU_DEBUGFS + bool "Export IOMMU internals in DebugFS" + depends on DEBUG_FS + help + Allows exposure of IOMMU device internals. This option enables + the use of debugfs by IOMMU drivers as required. Devices can, + at initialization time, cause the IOMMU code to create a top-level + debug/iommu directory, and then populate a subdirectory with + entries as required. + config IOMMU_IOVA tristate diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile index 1fb695854809..74cfbc392862 100644 --- a/drivers/iommu/Makefile +++ b/drivers/iommu/Makefile @@ -2,6 +2,7 @@ obj-$(CONFIG_IOMMU_API) += iommu.o obj-$(CONFIG_IOMMU_API) += iommu-traces.o obj-$(CONFIG_IOMMU_API) += iommu-sysfs.o +obj-$(CONFIG_IOMMU_DEBUGFS) += iommu-debugfs.o obj-$(CONFIG_IOMMU_DMA) += dma-iommu.o obj-$(CONFIG_IOMMU_IO_PGTABLE) += io-pgtable.o obj-$(CONFIG_IOMMU_IO_PGTABLE_ARMV7S) += io-pgtable-arm-v7s.o diff --git a/drivers/iommu/iommu-debugfs.c b/drivers/iommu/iommu-debugfs.c new file mode 100644 index 000000000000..3b1bf88fd1b0 --- /dev/null +++ b/drivers/iommu/iommu-debugfs.c @@ -0,0 +1,66 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * IOMMU debugfs core infrastructure + * + * Copyright (C) 2018 Advanced Micro Devices, Inc. + * + * Author: Gary R Hook <gary.hook@amd.com> + */ + +#include <linux/pci.h> +#include <linux/iommu.h> +#include <linux/debugfs.h> + +struct dentry *iommu_debugfs_dir; + +/** + * iommu_debugfs_setup - create the top-level iommu directory in debugfs + * + * Provide base enablement for using debugfs to expose internal data of an + * IOMMU driver. When called, this function creates 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; drivers may then call + * iommu_debugfs_new_driver_dir() to instantiate a vendor-specific + * directory to be used to expose internal data. + */ +void iommu_debugfs_setup(void) +{ + if (!iommu_debugfs_dir) { + iommu_debugfs_dir = debugfs_create_dir("iommu", NULL); + pr_warn("\n"); + pr_warn("*************************************************************\n"); + pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); + pr_warn("** **\n"); + pr_warn("** IOMMU DebugFS SUPPORT HAS BEEN ENABLED IN THIS KERNEL **\n"); + pr_warn("** **\n"); + pr_warn("** This means that this kernel is built to expose internal **\n"); + pr_warn("** IOMMU data structures, which may compromise security on **\n"); + pr_warn("** your system. **\n"); + pr_warn("** **\n"); + pr_warn("** If you see this message and you are not debugging the **\n"); + pr_warn("** kernel, report this immediately to your vendor! **\n"); + pr_warn("** **\n"); + pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); + pr_warn("*************************************************************\n"); + } +} + +/** + * iommu_debugfs_new_driver_dir - create a vendor directory under debugfs/iommu + * @vendor: name of the vendor-specific subdirectory to create + * + * This function is called by an IOMMU driver to create the top-level debugfs + * directory for that driver. + * + * Return: upon success, a pointer to the dentry for the new directory. + * NULL in case of failure. + */ +struct dentry *iommu_debugfs_new_driver_dir(const char *vendor) +{ + return debugfs_create_dir(vendor, iommu_debugfs_dir); +} +EXPORT_SYMBOL_GPL(iommu_debugfs_new_driver_dir); diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 63b37563db7e..d227b864a109 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -1748,6 +1748,8 @@ static int __init iommu_init(void) NULL, kernel_kobj); BUG_ON(!iommu_group_kset); + iommu_debugfs_setup(); + return 0; } core_initcall(iommu_init); |