Now that we have a sane API to set and clear memory permissions that
works the same on ARM and AArch64, we no longer have a need for the
individual set/clear no-access/read-only/no-exec helpers so let's drop
them.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Currently, ArmSetMemoryAttributes () takes a combination of
EFI_MEMORY_xx constants describing the memory type and permission
attributes that should be set on a region of memory. In cases where the
memory type is omitted, we assume that the memory permissions being set
are final, and that existing memory permissions can be discarded.
This is problematic, because we aim to map memory non-executable
(EFI_MEMORY_XP) by default, and only relax this requirement for code
regions that are mapped read-only (EFI_MEMORY_RO). Currently, setting
one permission clears the other, and so code managing these permissions
has to be aware of the existing permissions in order to be able to
preserve them, and this is not always tractable (e.g., the UEFI memory
attribute protocol implements an abstraction that promises to preserve
memory permissions that it is not operating on explicitly).
So let's add an AttributeMask parameter to ArmSetMemoryAttributes(),
which is permitted to be non-zero if no memory type is being provided,
in which case only memory permission attributes covered in the mask will
be affected by the update.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Oliver Smith-Denny <osde@linux.microsoft.com>
Reviewed-by: Michael Kubacki <michael.kubacki@microsoft.com>
Currently, the ARM MMU page table logic will break down any block entry
that overlaps with the region being mapped, even if the block entry in
question is using the same attributes as the new region.
This means that creating a non-executable mapping inside a region that
is already mapped non-executable at a coarser granularity may trigger a
call to AllocatePages (), which may recurse back into the page table
code to update the attributes on the newly allocated page tables.
Let's avoid this, by preserving the block entry if it already covers the
region being mapped with the correct attributes.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Implement support for read-protected memory by wiring it up to the
access flag in the page table descriptor. The resulting mapping is
implicitly non-writable and non-executable as well, but this is good
enough for implementing this attribute, as we never rely on write or
execute permissions without read permissions.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Currently, the MMU code that is supposed to clear the RO or XP
attributes from a region just clears both unconditionally. This
approximates the desired behavior to some extent, but it does mean that
setting the RO bit first on a code region, and then clearing the XP bit
results both RO and XP being cleared, and we end up with writable code,
and avoiding that is the point of all these protections.
Once we introduce RP support, this will only get worse, so let's fix
this up, by reshuffling the attribute update code to take the entry mask
from the caller, and use the mask to preserve other attributes when
clearing RO or XP.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Split the ARM permission fields in the short descriptors into an access
flag and AP[2:1] as per the recommendation in the ARM ARM. This makes
the access flag available separately, which allows us to implement
EFI_MEMORY_RP memory analogous to how it will be implemented for
AArch64.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
With large page support out of the picture, we can treat bits 1 and 0 of
the page descriptor as individual valid and XN bits, instead of treating
XN as a page type. Doing so aligns the handling of the attribute with
the section descriptor layout, as well as the XN handling on AArch64,
and this is beneficial for maintainability.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Large page support on 32-bit ARM is essentially a glorified contiguous
bit where 16 consecutive entries describing a contiguous range with the
same attributes are presented in a way that permits the TLB to cache its
translation with a single entry.
This was never wired up completely, and does not add a lot of value in
EFI, where the page granularity is 4k and we expect to be able to set RO
and XP permissions on individual pages.
Given that large page support complicates the handling of the XN bit at
the page level (which is in a different place depending on whether the
page is small or large), let's just rip it out.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3737
Apply uncrustify changes to .c/.h files in the ArmPkg package
Cc: Andrew Fish <afish@apple.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Andrew Fish <afish@apple.com>
The 'cspell' CI test detected some small typos in ArmPkg.
Correct them.
Cc: Bret Barkelew <bret.barkelew@microsoft.com>
Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
This patch fixes the following Ecc reported error:
There should be no initialization of a variable as
part of its declaration
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
This patch fixes the following Ecc reported error:
Non-Boolean comparisons should use a compare operator
(==, !=, >, < >=, <=)
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2835
There's several occurrences of a UINT64 or an EFI_PHYSICAL_ADDRESS
being assigned to a UINT32 value in ArmMmuLib. These result in
warning C4244 in VS2019:
warning C4244: '=': conversion from 'UINT64' to 'UINT32', possible
loss of data
warning C4244: '=': conversion from 'EFI_PHYSICAL_ADDRESS' to
'UINT32', possible loss of data
This change explicitly casts the values to UINT32.
These can be reproduced with the following build command:
build -b DEBUG -a ARM -t VS2019 -p ArmPkg/ArmPkg.dsc
-m ArmPkg/Library/ArmMmuLib/ArmMmuBaseLib.inf
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Unlike the AArch64 implementation of ArmMmuLib, which combines the
initial page table population code with the code that runs at later
stages to manage permission attributes in the page tables, ARM uses
two completely separate sets of routines for this.
Since ArmMmuLib is a static library, we can prevent duplication of
this code between different users, which usually only need one or
the other. (Note that LTO should also achieve the same.)
This also makes it easier to reason about modifying the cache
maintenance handling, and replace the set/way ops with by-VA
ops, since the code that performs the set/way ops only executes
when the MMU is still off.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
Ard Biesheuvel
Michael Kubacki
Pierre Gondois
Ard Biesheuvel