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ArmPkg/CpuDxe AARCH64: Report Memory Protection Attributes To GCD 

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4463

When the AARCH64 CpuDxe attempts to SyncCacheConfig() with the GCD, it
collects the page attributes as:

  EntryAttribute = Entry & TT_ATTR_INDX_MASK

However, TT_ATTR_INDX_MASK only masks the cacheability attributes and
drops the memory protections attributes. Importantly, it also drops the
TT_AF (access flag) which is now wired up in EDK2 to represent
EFI_MEMORY_RP, so by default all SystemMem pages will report as
EFI_MEMORY_RP to the GCD. The GCD currently drops that silently, because
the Capabilities field in the GCD does not support EFI_MEMORY_RP by
default.

However, some ranges may support EFI_MEMORY_RP and incorrectly mark
those ranges as read protected. In conjunction with another change on
the mailing list (see: https://edk2.groups.io/g/devel/topic/98505340),
this causes an access flag fault incorrectly. See the linked BZ below
for full details.

This patch exposes all memory protections attributes to the GCD layer so
it can correctly set pages as EFI_MEMORY[RP|XP|RO] when it initially
syncs.

Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Cc: Taylor Beebe <t@taylorbeebe.com>
Cc: Sean Brogan <sean.brogan@microsoft.com>
Signed-off-by: Oliver Smith-Denny <osde@linux.microsoft.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Michael Kubacki <michael.kubacki@microsoft.com>
This commit is contained in:
Oliver Smith-Denny 2023-05-23 13:36:23 -07:00 committed by mergify[bot]
parent 04c5b3023e
commit 647cd40cf6
1 changed files with 2 additions and 2 deletions
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4
ArmPkg/Drivers/CpuDxe/AArch64/Mmu.c
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@ -120,7 +120,7 @@ GetFirstPageAttribute (
} else if (((FirstEntry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY) ||
((TableLevel == 3) && ((FirstEntry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY_LEVEL3)))
{
return FirstEntry & TT_ATTR_INDX_MASK;
return FirstEntry & TT_ATTRIBUTES_MASK;
} else {
return INVALID_ENTRY;
}
@ -158,7 +158,7 @@ GetNextEntryAttribute (
for (Index = 0; Index < EntryCount; Index++) {
Entry = TableAddress[Index];
EntryType = Entry & TT_TYPE_MASK;
EntryAttribute = Entry & TT_ATTR_INDX_MASK;
EntryAttribute = Entry & TT_ATTRIBUTES_MASK;
// If Entry is a Table Descriptor type entry then go through the sub-level table
if ((EntryType == TT_TYPE_BLOCK_ENTRY) ||