On Sat, Mar 07, 2020 at 14:34:13 +0100, Ard Biesheuvel wrote: > Last one, I promise :-) > > The new ArmMmuLib code is easier to reason about, so that is what I did: > currently, when we create mappings that cover existing table entries, we > may end up overwriting those with block entries without taking the mapping > attributes of the original table entries into account. So let's fix this. > > I honestly don't know whether the original code was better at dealing with > this: I do remember some changes from Heyi that may have been related, but > the old code is not easy to follow. In any case, I didn't manage to hit this > case in practice, given that we typically start out with large mappings, and > break them down later (to set permissions), rather than the other way around. > > Patch #1 adds some helpers to hide the insane way the type bits change > meaning when you change to level 3. > > Patch #2 ensures that we only replace (and free) table entries with block > entries if it is guaranteed that doing so will not lose any attribute > information.
For the series: Reviewed-by: Leif Lindholm <l...@nuviainc.com> Thanks! > Ard Biesheuvel (2): > ArmPkg/ArmMmuLib AARCH64: use helpers to determine table entry types > ArmPkg/ArmMmuLib AARCH64: preserve attributes when replacing a table > entry > > .../Library/ArmMmuLib/AArch64/ArmMmuLibCore.c | 61 ++++++++++++++++--- > 1 file changed, 54 insertions(+), 7 deletions(-) > > -- > 2.17.1 > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#55688): https://edk2.groups.io/g/devel/message/55688 Mute This Topic: https://groups.io/mt/71795102/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
