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>
This commit is contained in:
Gary R Hook 2018-06-12 16:41:21 -05:00 committed by Joerg Roedel
parent 021c91791a
commit bad614b242
5 changed files with 86 additions and 0 deletions

View file

@ -698,4 +698,11 @@ const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode)
#endif /* CONFIG_IOMMU_API */
#ifdef CONFIG_IOMMU_DEBUGFS
extern struct dentry *iommu_debugfs_dir;
void iommu_debugfs_setup(void);
#else
static inline void iommu_debugfs_setup(void) {}
#endif
#endif /* __LINUX_IOMMU_H */