iommu/io-pgtable-arm: Add read_and_clear_dirty() support

.read_and_clear_dirty() IOMMU domain op takes care of reading the dirty
bits (i.e. PTE has DBM set and AP[2] clear) and marshalling into a
bitmap of a given page size.

While reading the dirty bits we also set the PTE AP[2] bit to mark it
as writeable-clean depending on read_and_clear_dirty() flags.

PTE states with respect to DBM bit:

                       DBM bit        AP[2]("RDONLY" bit)
1. writable_clean        1                 1
2. writable_dirty        1                 0
3. read-only             0                 1

Reviewed-by: Ryan Roberts <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Signed-off-by: Shameer Kolothum <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

0 files changed, 0 insertions, 0 deletions