On Mon, Apr 30, 2018 at 02:58:49PM -0500, Gary R Hook wrote:
> 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()
That function should be called in iommu core-code, in case we want to
export some generic information from there.
Each driver then calls a separate function like
dentry = iommu_debugfs_driver_dir("amd_iommu");
to create a driver-specific directory.
> +config IOMMU_DEBUGFS
> + bool "Enable IOMMU internals in DebugFS"
s/Enable/Export/
> + * static struct dentry *my_debugfs;
> + *
> + * struct dentry *d_top;
Missing newline
> + * 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 (!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");
This warning needs to be a lot bigger. See the trace_printk() warning
for an example of what I have in mind.
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