On 3/29/2018 5:54 PM, Gary R Hook wrote:
> Provide base enablement for using debugfs to expose internal data of
> an IOMMU driver. When enabled, create the /sys/kernel/debug/iommu
So this can't actually create anything yet since nothing invokes the
function. Maybe describe how it should be used by other drivers (and
probably include that description as a commment for the function) to
create the directory.
> directory. Emit a strong warning at boot time to indicate that this
> feature is enabled.
>
> Signed-off-by: Gary R Hook <gary.h...@amd.com>
> ---
> drivers/iommu/Kconfig | 11 +++++++++++
> drivers/iommu/Makefile | 2 ++
> drivers/iommu/amd_iommu_init.c | 2 ++
> drivers/iommu/iommu-debugfs.c | 32 ++++++++++++++++++++++++++++++++
> include/linux/iommu.h | 4 ++++
> 5 files changed, 51 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..5e5c3339681d 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-$(CONFIG_IOMMU_IO_PGTABLE_ARMV7S) += io-pgtable-arm-v7s.o
> @@ -10,6 +11,7 @@ obj-$(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_AMD_IOMMU_DEBUG) += amd_iommu_debugfs.o
Where is this CONFIG defined?
> 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_init.c b/drivers/iommu/amd_iommu_init.c
> index 6fe2d0346073..99d48c42a12f 100644
> --- a/drivers/iommu/amd_iommu_init.c
> +++ b/drivers/iommu/amd_iommu_init.c
> @@ -2783,6 +2783,8 @@ int __init amd_iommu_detect(void)
> iommu_detected = 1;
> x86_init.iommu.iommu_init = amd_iommu_init;
>
> +dump_stack();
> +
This definitely shouldn't be here.
> return 1;
> }
>
> diff --git a/drivers/iommu/iommu-debugfs.c b/drivers/iommu/iommu-debugfs.c
> new file mode 100644
> index 000000000000..94c9acc63b65
> --- /dev/null
> +++ b/drivers/iommu/iommu-debugfs.c
> @@ -0,0 +1,32 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * AMD IOMMU driver
This isn't the AMD IOMMU driver.
> + *
> + * Copyright (C) 2018 Advanced Micro Devices, Inc.
> + *
> + * Author: Gary R Hook <gary.h...@amd.com>
> + */
> +
> +#include <linux/pci.h>
> +#include <linux/iommu.h>
> +#include <linux/debugfs.h>
> +
> +static struct dentry *iommu_debugfs_dir;
> +
> +#define MAX_NAME_LEN 20
This isn't used anywhere.
> +
> +/* Return a zero on failure; 1 on successful setup */
Return NULL on failure, pointer to IOMMU debugfs dentry on success.
> +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..cb2957dac43b 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -696,6 +696,10 @@ const struct iommu_ops *iommu_ops_from_fwnode(struct
> fwnode_handle *fwnode)
> return NULL;
> }
>
> +#ifdef CONFIG_IOMMU_DEBUG
Should be a space between the #ifdef and the CONFIG_..., not a tab.
Thanks,
Tom
> +struct dentry *iommu_debugfs_setup(void);
> +#endif
> +
> #endif /* CONFIG_IOMMU_API */
>
> #endif /* __LINUX_IOMMU_H */
>
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