These patches create a top-level function to create a debugfs directory
for the IOMMU, under which drivers may create and populate-specific
directories for their device internals.
Patch 1: general IOMMU enablement
Patch 2: basic AMD enablement to demonstrate linkage with patch 1
Introduce a new Kconfig parameter IOMMU_DEBUG to globally allow or
disallow debugfs code to be built.
Changes since v1:
- Remove debug cruft
- Remove cruft produced by design change
- Change the lock to a mutex
- Coding style fixes
- Add a comment to document the framework
---
Gary R Hook (2):
iommu - Enable debugfs exposure of the IOMMU
iommu/amd: Add basic debugfs infrastructure for AMD IOMMU
drivers/iommu/Kconfig | 11 +++++++
drivers/iommu/Makefile | 2 +
drivers/iommu/amd_iommu_debugfs.c | 45 +++++++++++++++++++++++++++++
drivers/iommu/amd_iommu_init.c | 7 +++-
drivers/iommu/amd_iommu_proto.h | 8 ++++-
drivers/iommu/amd_iommu_types.h | 3 ++
drivers/iommu/iommu-debugfs.c | 58 +++++++++++++++++++++++++++++++++++++
include/linux/iommu.h | 4 +++
8 files changed, 135 insertions(+), 3 deletions(-)
create mode 100644 drivers/iommu/amd_iommu_debugfs.c
create mode 100644 drivers/iommu/iommu-debugfs.c
--
Signature
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 patch adds a top-level function that will create the (above)
directory, under which a driver may create a hw-specific directory for
its use. The function
iommu_debugfs_setup()
returns a pointer to the new dentry structure created for
/sys/kernel/debug/iommu, or NULL in the event of a failure. An IOMMU
driver should call this function first, and then create a directory
beneath it. A driver implementation might look something like:
static struct dentry *my_debugfs;
struct dentry *d_top;
if (!my_debugfs) {
d_top = iommu_debugfs_setup();
if (d_top)
my_debugfs = debugfs_create_dir("vendor", d_top);
}
Since the IOMMU driver can not be removed from the running system, this
patch only provides an "on" function.
Signed-off-by: Gary R Hook <[email protected]>
---
drivers/iommu/Kconfig | 11 ++++++++
drivers/iommu/Makefile | 1 +
drivers/iommu/iommu-debugfs.c | 58 +++++++++++++++++++++++++++++++++++++++++
include/linux/iommu.h | 4 +++
4 files changed, 74 insertions(+)
create mode 100644 drivers/iommu/iommu-debugfs.c
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index f3a21343e636..c1e39dabfec2 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -60,6 +60,17 @@ config IOMMU_IO_PGTABLE_ARMV7S_SELFTEST
endmenu
+config IOMMU_DEBUG
+ bool "Enable IOMMU internals in DebugFS"
+ depends on DEBUG_FS
+ default n
+ 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..5eb1121d54b9 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_DEBUG) += 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..add6f95120e4
--- /dev/null
+++ b/drivers/iommu/iommu-debugfs.c
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * IOMMU driver
+ *
+ * Copyright (C) 2018 Advanced Micro Devices, Inc.
+ *
+ * Author: Gary R Hook <[email protected]>
+ */
+
+#include <linux/pci.h>
+#include <linux/iommu.h>
+#include <linux/debugfs.h>
+
+static struct dentry *iommu_debugfs_dir;
+
+/*
+ * 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 top-level function that will create the (above) directory, under a
+ * driver may create a hw-specific directory for its use. The function
+ *
+ * iommu_debugfs_setup()
+ *
+ * returns a pointer to the new dentry structure created for
+ * /sys/kernel/debug/iommu, or NULL in the event of a failure. An IOMMU
+ * driver should call this function first, and then create a directory
+ * beneath it. A driver implementation might look something like:
+ *
+ * static struct dentry *my_debugfs;
+ *
+ * struct dentry *d_top;
+ * if (!my_debugfs) {
+ * d_top = iommu_debugfs_setup();
+ * if (d_top)
+ * my_debugfs = debugfs_create_dir("vendor", d_top);
+ * }
+ *
+ * Since the IOMMU driver can not be removed from the running system, there
+ * is no need for an "off" function.
+ */
+struct dentry *iommu_debugfs_setup(void)
+{
+ if (!debugfs_initialized())
+ return NULL;
+
+ if (!iommu_debugfs_dir)
+ iommu_debugfs_dir = debugfs_create_dir("iommu", NULL);
+
+ if (iommu_debugfs_dir)
+ pr_warn("WARNING: IOMMU DEBUGFS SUPPORT HAS BEEN ENABLED IN THIS KERNEL\n");
+
+ return iommu_debugfs_dir;
+}
+EXPORT_SYMBOL_GPL(iommu_debugfs_setup);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 41b8c5757859..3dd2e73d31c4 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -412,6 +412,10 @@ void iommu_fwspec_free(struct device *dev);
int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids);
const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode);
+#ifdef CONFIG_IOMMU_DEBUG
+struct dentry *iommu_debugfs_setup(void);
+#endif
+
#else /* CONFIG_IOMMU_API */
struct iommu_ops {};
Implement a skeleton framework for debugfs support in the
AMD IOMMU.
Signed-off-by: Gary R Hook <[email protected]>
---
drivers/iommu/Makefile | 1 +
drivers/iommu/amd_iommu_debugfs.c | 45 +++++++++++++++++++++++++++++++++++++
drivers/iommu/amd_iommu_init.c | 7 ++++--
drivers/iommu/amd_iommu_proto.h | 8 ++++++-
drivers/iommu/amd_iommu_types.h | 3 ++
5 files changed, 61 insertions(+), 3 deletions(-)
create mode 100644 drivers/iommu/amd_iommu_debugfs.c
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 5eb1121d54b9..0ca250f626d9 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_IOMMU_IOVA) += iova.o
obj-$(CONFIG_OF_IOMMU) += of_iommu.o
obj-$(CONFIG_MSM_IOMMU) += msm_iommu.o
obj-$(CONFIG_AMD_IOMMU) += amd_iommu.o amd_iommu_init.o
+obj-$(CONFIG_IOMMU_DEBUG) += amd_iommu_debugfs.o
obj-$(CONFIG_AMD_IOMMU_V2) += amd_iommu_v2.o
obj-$(CONFIG_ARM_SMMU) += arm-smmu.o
obj-$(CONFIG_ARM_SMMU_V3) += arm-smmu-v3.o
diff --git a/drivers/iommu/amd_iommu_debugfs.c b/drivers/iommu/amd_iommu_debugfs.c
new file mode 100644
index 000000000000..282100a655b3
--- /dev/null
+++ b/drivers/iommu/amd_iommu_debugfs.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD IOMMU driver
+ *
+ * Copyright (C) 2018 Advanced Micro Devices, Inc.
+ *
+ * Author: Gary R Hook <[email protected]>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/iommu.h>
+#include <linux/pci.h>
+#include "amd_iommu_proto.h"
+#include "amd_iommu_types.h"
+
+static struct dentry *amd_iommu_debugfs;
+static DEFINE_MUTEX(amd_iommu_debugfs_lock);
+
+#define MAX_NAME_LEN 20
+
+void amd_iommu_debugfs_setup(struct amd_iommu *iommu)
+{
+ char name[MAX_NAME_LEN + 1];
+ struct dentry *d_top;
+
+ if (!debugfs_initialized())
+ return;
+
+ mutex_lock(&amd_iommu_debugfs_lock);
+ if (!amd_iommu_debugfs) {
+ d_top = iommu_debugfs_setup();
+ if (d_top)
+ amd_iommu_debugfs = debugfs_create_dir("amd", d_top);
+ }
+ mutex_unlock(&amd_iommu_debugfs_lock);
+ if (amd_iommu_debugfs) {
+ snprintf(name, MAX_NAME_LEN, "iommu%02d", iommu->index);
+ iommu->debugfs = debugfs_create_dir(name,
+ amd_iommu_debugfs);
+ if (!iommu->debugfs) {
+ debugfs_remove_recursive(amd_iommu_debugfs);
+ amd_iommu_debugfs = NULL;
+ }
+ }
+}
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 6fe2d0346073..43856c7f4ea1 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -89,6 +89,7 @@
#define ACPI_DEVFLAG_ATSDIS 0x10000000
#define LOOP_TIMEOUT 100000
+
/*
* ACPI table definitions
*
@@ -2720,6 +2721,7 @@ int __init amd_iommu_enable_faulting(void)
*/
static int __init amd_iommu_init(void)
{
+ struct amd_iommu *iommu;
int ret;
ret = iommu_go_to_state(IOMMU_INITIALIZED);
@@ -2729,14 +2731,15 @@ static int __init amd_iommu_init(void)
disable_iommus();
free_iommu_resources();
} else {
- struct amd_iommu *iommu;
-
uninit_device_table_dma();
for_each_iommu(iommu)
iommu_flush_all_caches(iommu);
}
}
+ for_each_iommu(iommu)
+ amd_iommu_debugfs_setup(iommu);
+
return ret;
}
diff --git a/drivers/iommu/amd_iommu_proto.h b/drivers/iommu/amd_iommu_proto.h
index 640c286a0ab9..1cfaae28c2cd 100644
--- a/drivers/iommu/amd_iommu_proto.h
+++ b/drivers/iommu/amd_iommu_proto.h
@@ -33,6 +33,12 @@ extern void amd_iommu_uninit_devices(void);
extern void amd_iommu_init_notifier(void);
extern int amd_iommu_init_api(void);
+#ifdef CONFIG_IOMMU_DEBUG
+void amd_iommu_debugfs_setup(struct amd_iommu *iommu);
+#else
+static inline void amd_iommu_debugfs_setup(struct amd_iommu *iommu) {}
+#endif
+
/* Needed for interrupt remapping */
extern int amd_iommu_prepare(void);
extern int amd_iommu_enable(void);
@@ -58,7 +64,7 @@ extern int amd_iommu_domain_clear_gcr3(struct iommu_domain *dom, int pasid);
extern struct iommu_domain *amd_iommu_get_v2_domain(struct pci_dev *pdev);
#ifdef CONFIG_IRQ_REMAP
-extern int amd_iommu_create_irq_domain(struct amd_iommu *iommu);
+int amd_iommu_create_irq_domain(struct amd_iommu *iommu);
#else
static inline int amd_iommu_create_irq_domain(struct amd_iommu *iommu)
{
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index f6b24c7d8b70..43c52797810e 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -591,6 +591,9 @@ struct amd_iommu {
u32 flags;
volatile u64 __aligned(8) cmd_sem;
+
+ /* DebugFS Info */
+ struct dentry *debugfs;
};
static inline struct amd_iommu *dev_to_amd_iommu(struct device *dev)
Hi Gary,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on iommu/next]
[also build test ERROR on v4.16 next-20180404]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Gary-R-Hook/iommu-Enable-debugfs-exposure-of-the-IOMMU/20180405-151608
base: https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next
config: x86_64-randconfig-x002-201813 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All error/warnings (new ones prefixed by >>):
drivers//iommu/amd_iommu_debugfs.c: In function 'amd_iommu_debugfs_setup':
>> drivers//iommu/amd_iommu_debugfs.c:31:11: error: implicit declaration of function 'iommu_debugfs_setup'; did you mean 'amd_iommu_debugfs_setup'? [-Werror=implicit-function-declaration]
d_top = iommu_debugfs_setup();
^~~~~~~~~~~~~~~~~~~
amd_iommu_debugfs_setup
>> drivers//iommu/amd_iommu_debugfs.c:31:9: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
d_top = iommu_debugfs_setup();
^
cc1: some warnings being treated as errors
vim +31 drivers//iommu/amd_iommu_debugfs.c
20
21 void amd_iommu_debugfs_setup(struct amd_iommu *iommu)
22 {
23 char name[MAX_NAME_LEN + 1];
24 struct dentry *d_top;
25
26 if (!debugfs_initialized())
27 return;
28
29 mutex_lock(&amd_iommu_debugfs_lock);
30 if (!amd_iommu_debugfs) {
> 31 d_top = iommu_debugfs_setup();
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Hi Gary,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on iommu/next]
[also build test ERROR on v4.16 next-20180405]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Gary-R-Hook/iommu-Enable-debugfs-exposure-of-the-IOMMU/20180405-151608
base: https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next
config: x86_64-randconfig-s2-04060234 (attached as .config)
compiler: gcc-6 (Debian 6.4.0-9) 6.4.0 20171026
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All errors (new ones prefixed by >>):
drivers//iommu/amd_iommu_debugfs.c: In function 'amd_iommu_debugfs_setup':
>> drivers//iommu/amd_iommu_debugfs.c:31:11: error: implicit declaration of function 'iommu_debugfs_setup' [-Werror=implicit-function-declaration]
d_top = iommu_debugfs_setup();
^~~~~~~~~~~~~~~~~~~
drivers//iommu/amd_iommu_debugfs.c:31:9: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
d_top = iommu_debugfs_setup();
^
cc1: some warnings being treated as errors
vim +/iommu_debugfs_setup +31 drivers//iommu/amd_iommu_debugfs.c
20
21 void amd_iommu_debugfs_setup(struct amd_iommu *iommu)
22 {
23 char name[MAX_NAME_LEN + 1];
24 struct dentry *d_top;
25
26 if (!debugfs_initialized())
27 return;
28
29 mutex_lock(&amd_iommu_debugfs_lock);
30 if (!amd_iommu_debugfs) {
> 31 d_top = iommu_debugfs_setup();
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
On 4/4/2018 1:55 PM, Gary R Hook wrote:
> Implement a skeleton framework for debugfs support in the
> AMD IOMMU.
>
>
> Signed-off-by: Gary R Hook <[email protected]>
> ---
> drivers/iommu/Makefile | 1 +
> drivers/iommu/amd_iommu_debugfs.c | 45 +++++++++++++++++++++++++++++++++++++
> drivers/iommu/amd_iommu_init.c | 7 ++++--
> drivers/iommu/amd_iommu_proto.h | 8 ++++++-
> drivers/iommu/amd_iommu_types.h | 3 ++
> 5 files changed, 61 insertions(+), 3 deletions(-)
> create mode 100644 drivers/iommu/amd_iommu_debugfs.c
>
> diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
> index 5eb1121d54b9..0ca250f626d9 100644
> --- a/drivers/iommu/Makefile
> +++ b/drivers/iommu/Makefile
> @@ -11,6 +11,7 @@ obj-$(CONFIG_IOMMU_IOVA) += iova.o
> obj-$(CONFIG_OF_IOMMU) += of_iommu.o
> obj-$(CONFIG_MSM_IOMMU) += msm_iommu.o
> obj-$(CONFIG_AMD_IOMMU) += amd_iommu.o amd_iommu_init.o
> +obj-$(CONFIG_IOMMU_DEBUG) += amd_iommu_debugfs.o
> obj-$(CONFIG_AMD_IOMMU_V2) += amd_iommu_v2.o
> obj-$(CONFIG_ARM_SMMU) += arm-smmu.o
> obj-$(CONFIG_ARM_SMMU_V3) += arm-smmu-v3.o
> diff --git a/drivers/iommu/amd_iommu_debugfs.c b/drivers/iommu/amd_iommu_debugfs.c
> new file mode 100644
> index 000000000000..282100a655b3
> --- /dev/null
> +++ b/drivers/iommu/amd_iommu_debugfs.c
> @@ -0,0 +1,45 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * AMD IOMMU driver
> + *
> + * Copyright (C) 2018 Advanced Micro Devices, Inc.
> + *
> + * Author: Gary R Hook <[email protected]>
> + */
> +
> +#include <linux/debugfs.h>
> +#include <linux/iommu.h>
> +#include <linux/pci.h>
> +#include "amd_iommu_proto.h"
> +#include "amd_iommu_types.h"
> +
> +static struct dentry *amd_iommu_debugfs;
> +static DEFINE_MUTEX(amd_iommu_debugfs_lock);
> +
> +#define MAX_NAME_LEN 20
> +
> +void amd_iommu_debugfs_setup(struct amd_iommu *iommu)
> +{
> + char name[MAX_NAME_LEN + 1];
> + struct dentry *d_top;
> +
> + if (!debugfs_initialized())
> + return;
> +
> + mutex_lock(&amd_iommu_debugfs_lock);
> + if (!amd_iommu_debugfs) {
> + d_top = iommu_debugfs_setup();
> + if (d_top)
> + amd_iommu_debugfs = debugfs_create_dir("amd", d_top);
> + }
> + mutex_unlock(&amd_iommu_debugfs_lock);
> + if (amd_iommu_debugfs) {
> + snprintf(name, MAX_NAME_LEN, "iommu%02d", iommu->index);
> + iommu->debugfs = debugfs_create_dir(name,
> + amd_iommu_debugfs);
> + if (!iommu->debugfs) {
> + debugfs_remove_recursive(amd_iommu_debugfs);
> + amd_iommu_debugfs = NULL;
> + }
> + }
> +}
> diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
> index 6fe2d0346073..43856c7f4ea1 100644
> --- a/drivers/iommu/amd_iommu_init.c
> +++ b/drivers/iommu/amd_iommu_init.c
> @@ -89,6 +89,7 @@
> #define ACPI_DEVFLAG_ATSDIS 0x10000000
>
> #define LOOP_TIMEOUT 100000
> +
Spurious new line.
> /*
> * ACPI table definitions
> *
> @@ -2720,6 +2721,7 @@ int __init amd_iommu_enable_faulting(void)
> */
> static int __init amd_iommu_init(void)
> {
> + struct amd_iommu *iommu;
> int ret;
>
> ret = iommu_go_to_state(IOMMU_INITIALIZED);
> @@ -2729,14 +2731,15 @@ static int __init amd_iommu_init(void)
> disable_iommus();
> free_iommu_resources();
> } else {
> - struct amd_iommu *iommu;
> -
> uninit_device_table_dma();
> for_each_iommu(iommu)
> iommu_flush_all_caches(iommu);
> }
> }
>
> + for_each_iommu(iommu)
> + amd_iommu_debugfs_setup(iommu);
> +
> return ret;
> }
>
> diff --git a/drivers/iommu/amd_iommu_proto.h b/drivers/iommu/amd_iommu_proto.h
> index 640c286a0ab9..1cfaae28c2cd 100644
> --- a/drivers/iommu/amd_iommu_proto.h
> +++ b/drivers/iommu/amd_iommu_proto.h
> @@ -33,6 +33,12 @@ extern void amd_iommu_uninit_devices(void);
> extern void amd_iommu_init_notifier(void);
> extern int amd_iommu_init_api(void);
>
> +#ifdef CONFIG_IOMMU_DEBUG
> +void amd_iommu_debugfs_setup(struct amd_iommu *iommu);
> +#else
> +static inline void amd_iommu_debugfs_setup(struct amd_iommu *iommu) {}
> +#endif
> +
> /* Needed for interrupt remapping */
> extern int amd_iommu_prepare(void);
> extern int amd_iommu_enable(void);
> @@ -58,7 +64,7 @@ extern int amd_iommu_domain_clear_gcr3(struct iommu_domain *dom, int pasid);
> extern struct iommu_domain *amd_iommu_get_v2_domain(struct pci_dev *pdev);
>
> #ifdef CONFIG_IRQ_REMAP
> -extern int amd_iommu_create_irq_domain(struct amd_iommu *iommu);
> +int amd_iommu_create_irq_domain(struct amd_iommu *iommu);
I don't think this change is required for the debugfs support.
Thanks,
Tom
> #else
> static inline int amd_iommu_create_irq_domain(struct amd_iommu *iommu)
> {
> diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
> index f6b24c7d8b70..43c52797810e 100644
> --- a/drivers/iommu/amd_iommu_types.h
> +++ b/drivers/iommu/amd_iommu_types.h
> @@ -591,6 +591,9 @@ struct amd_iommu {
>
> u32 flags;
> volatile u64 __aligned(8) cmd_sem;
> +
> + /* DebugFS Info */
> + struct dentry *debugfs;
> };
>
> static inline struct amd_iommu *dev_to_amd_iommu(struct device *dev)
>