[PATCH v3 2/3] ArmPkg/ArmMmuLib AARCH64: use helpers to determine table entry types


Ard Biesheuvel
 

Given how the meaning of the attribute bits for page table entry types
is slightly awkward, and changes between levels, add some helpers to
abstract from this.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
---
ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c | 40 +++++++++++++++++---
1 file changed, 35 insertions(+), 5 deletions(-)

diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
index d78918cf7ba8..0680ba36d907 100644
--- a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
+++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
@@ -162,6 +162,36 @@ FreePageTablesRecursive (
FreePages (TranslationTable, 1);
}

+STATIC
+BOOLEAN
+IsBlockEntry (
+ IN UINT64 Entry,
+ IN UINTN Level
+ )
+{
+ if (Level == 3) {
+ return (Entry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY_LEVEL3;
+ }
+ return (Entry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY;
+}
+
+STATIC
+BOOLEAN
+IsTableEntry (
+ IN UINT64 Entry,
+ IN UINTN Level
+ )
+{
+ if (Level == 3) {
+ //
+ // TT_TYPE_TABLE_ENTRY aliases TT_TYPE_BLOCK_ENTRY_LEVEL3
+ // so we need to take the level into account as well.
+ //
+ return FALSE;
+ }
+ return (Entry & TT_TYPE_MASK) == TT_TYPE_TABLE_ENTRY;
+}
+
STATIC
EFI_STATUS
UpdateRegionMappingRecursive (
@@ -203,7 +233,7 @@ UpdateRegionMappingRecursive (
if (Level == 0 || ((RegionStart | BlockEnd) & BlockMask) != 0) {
ASSERT (Level < 3);

- if ((*Entry & TT_TYPE_MASK) != TT_TYPE_TABLE_ENTRY) {
+ if (!IsTableEntry (*Entry, Level)) {
//
// No table entry exists yet, so we need to allocate a page table
// for the next level.
@@ -221,7 +251,7 @@ UpdateRegionMappingRecursive (
InvalidateDataCacheRange (TranslationTable, EFI_PAGE_SIZE);
}

- if ((*Entry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY) {
+ if (IsBlockEntry (*Entry, Level)) {
//
// We are splitting an existing block entry, so we have to populate
// the new table with the attributes of the block entry it replaces.
@@ -252,7 +282,7 @@ UpdateRegionMappingRecursive (
AttributeSetMask, AttributeClearMask, TranslationTable,
Level + 1);
if (EFI_ERROR (Status)) {
- if ((*Entry & TT_TYPE_MASK) != TT_TYPE_TABLE_ENTRY) {
+ if (!IsTableEntry (*Entry, Level)) {
//
// We are creating a new table entry, so on failure, we can free all
// allocations we made recursively, given that the whole subhierarchy
@@ -265,10 +295,10 @@ UpdateRegionMappingRecursive (
return Status;
}

- if ((*Entry & TT_TYPE_MASK) != TT_TYPE_TABLE_ENTRY) {
+ if (!IsTableEntry (*Entry, Level)) {
EntryValue = (UINTN)TranslationTable | TT_TYPE_TABLE_ENTRY;
ReplaceTableEntry (Entry, EntryValue, RegionStart,
- (*Entry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY);
+ IsBlockEntry (*Entry, Level));
}
} else {
EntryValue = (*Entry & AttributeClearMask) | AttributeSetMask;
--
2.17.1

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