[edk2-devel] [PATCH v3 1/2] ArmPkg/ArmMmuLib AARCH64: rewrite page table code
Ard Biesheuvel
ard.biesheuvel at linaro.org
Fri Mar 6 16:12:45 UTC 2020
Replace the slightly overcomplicated page table management code with
a simplified, recursive implementation that should be far easier to
reason about.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
---
ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c | 332 +++++++-------------
1 file changed, 108 insertions(+), 224 deletions(-)
diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
index 204e33c75f95..e36594fea3ad 100644
--- a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
+++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
@@ -121,14 +121,16 @@ GetRootTranslationTableInfo (
STATIC
VOID
-ReplaceLiveEntry (
+ReplaceTableEntry (
IN UINT64 *Entry,
IN UINT64 Value,
- IN UINT64 RegionStart
+ IN UINT64 RegionStart,
+ IN BOOLEAN IsLiveBlockMapping
)
{
- if (!ArmMmuEnabled ()) {
+ if (!ArmMmuEnabled () || !IsLiveBlockMapping) {
*Entry = Value;
+ ArmUpdateTranslationTableEntry (Entry, (VOID *)(UINTN)RegionStart);
} else {
ArmReplaceLiveTranslationEntry (Entry, Value, RegionStart);
}
@@ -165,229 +167,132 @@ LookupAddresstoRootTable (
}
STATIC
-UINT64*
-GetBlockEntryListFromAddress (
- IN UINT64 *RootTable,
- IN UINT64 RegionStart,
- OUT UINTN *TableLevel,
- IN OUT UINT64 *BlockEntrySize,
- OUT UINT64 **LastBlockEntry
+EFI_STATUS
+UpdateRegionMappingRec (
+ IN UINT64 RegionStart,
+ IN UINT64 RegionEnd,
+ IN UINT64 AttributeSetMask,
+ IN UINT64 AttributeClearMask,
+ IN UINT64 *PageTable,
+ IN UINTN Level
)
{
- UINTN RootTableLevel;
- UINTN RootTableEntryCount;
- UINT64 *TranslationTable;
- UINT64 *BlockEntry;
- UINT64 *SubTableBlockEntry;
- UINT64 BlockEntryAddress;
- UINTN BaseAddressAlignment;
- UINTN PageLevel;
- UINTN Index;
- UINTN IndexLevel;
- UINTN T0SZ;
- UINT64 Attributes;
- UINT64 TableAttributes;
-
- // Initialize variable
- BlockEntry = NULL;
-
- // Ensure the parameters are valid
- if (!(TableLevel && BlockEntrySize && LastBlockEntry)) {
- ASSERT_EFI_ERROR (EFI_INVALID_PARAMETER);
- return NULL;
- }
-
- // Ensure the Region is aligned on 4KB boundary
- if ((RegionStart & (SIZE_4KB - 1)) != 0) {
- ASSERT_EFI_ERROR (EFI_INVALID_PARAMETER);
- return NULL;
- }
-
- // Ensure the required size is aligned on 4KB boundary and not 0
- if ((*BlockEntrySize & (SIZE_4KB - 1)) != 0 || *BlockEntrySize == 0) {
- ASSERT_EFI_ERROR (EFI_INVALID_PARAMETER);
- return NULL;
- }
-
- T0SZ = ArmGetTCR () & TCR_T0SZ_MASK;
- // Get the Table info from T0SZ
- GetRootTranslationTableInfo (T0SZ, &RootTableLevel, &RootTableEntryCount);
-
- // If the start address is 0x0 then we use the size of the region to identify the alignment
- if (RegionStart == 0) {
- // Identify the highest possible alignment for the Region Size
- BaseAddressAlignment = LowBitSet64 (*BlockEntrySize);
- } else {
- // Identify the highest possible alignment for the Base Address
- BaseAddressAlignment = LowBitSet64 (RegionStart);
- }
-
- // Identify the Page Level the RegionStart must belong to. Note that PageLevel
- // should be at least 1 since block translations are not supported at level 0
- PageLevel = MAX (3 - ((BaseAddressAlignment - 12) / 9), 1);
-
- // If the required size is smaller than the current block size then we need to go to the page below.
- // The PageLevel was calculated on the Base Address alignment but did not take in account the alignment
- // of the allocation size
- while (*BlockEntrySize < TT_BLOCK_ENTRY_SIZE_AT_LEVEL (PageLevel)) {
- // It does not fit so we need to go a page level above
- PageLevel++;
- }
-
- //
- // Get the Table Descriptor for the corresponding PageLevel. We need to decompose RegionStart to get appropriate entries
- //
-
- TranslationTable = RootTable;
- for (IndexLevel = RootTableLevel; IndexLevel <= PageLevel; IndexLevel++) {
- BlockEntry = (UINT64*)TT_GET_ENTRY_FOR_ADDRESS (TranslationTable, IndexLevel, RegionStart);
-
- if ((IndexLevel != 3) && ((*BlockEntry & TT_TYPE_MASK) == TT_TYPE_TABLE_ENTRY)) {
- // Go to the next table
- TranslationTable = (UINT64*)(*BlockEntry & TT_ADDRESS_MASK_DESCRIPTION_TABLE);
-
- // If we are at the last level then update the last level to next level
- if (IndexLevel == PageLevel) {
- // Enter the next level
- PageLevel++;
- }
- } else if ((*BlockEntry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY) {
- // If we are not at the last level then we need to split this BlockEntry
- if (IndexLevel != PageLevel) {
- // Retrieve the attributes from the block entry
- Attributes = *BlockEntry & TT_ATTRIBUTES_MASK;
-
- // Convert the block entry attributes into Table descriptor attributes
- TableAttributes = TT_TABLE_AP_NO_PERMISSION;
- if (Attributes & TT_NS) {
- TableAttributes = TT_TABLE_NS;
+ UINTN BlockShift;
+ UINT64 BlockMask;
+ UINT64 BlockEnd;
+ UINT64 *Entry;
+ UINT64 EntryValue;
+ VOID *TranslationTable;
+ EFI_STATUS Status;
+
+ ASSERT (((RegionStart | RegionEnd) & EFI_PAGE_MASK) == 0);
+
+ BlockShift = (Level + 1) * BITS_PER_LEVEL + MIN_T0SZ;
+ BlockMask = MAX_UINT64 >> BlockShift;
+
+ DEBUG ((DEBUG_VERBOSE, "%a(%d): %llx - %llx set %lx clr %lx\n", __FUNCTION__,
+ Level, RegionStart, RegionEnd, AttributeSetMask, AttributeClearMask));
+
+ for (; RegionStart < RegionEnd; RegionStart = BlockEnd) {
+ BlockEnd = MIN (RegionEnd, (RegionStart | BlockMask) + 1);
+ Entry = &PageTable[(RegionStart >> (64 - BlockShift)) & (TT_ENTRY_COUNT - 1)];
+
+ //
+ // If RegionStart or BlockEnd is not aligned to the block size at this
+ // level, we will have to create a table mapping in order to map less
+ // than a block, and recurse to create the block or page entries at
+ // the next level. No block mappings are allowed at all at level 0,
+ // so in that case, we have to recurse unconditionally.
+ //
+ if (Level == 0 || ((RegionStart | BlockEnd) & BlockMask) != 0) {
+ ASSERT (Level < 3);
+
+ if ((*Entry & TT_TYPE_MASK) != TT_TYPE_TABLE_ENTRY) {
+ //
+ // No table entry exists yet, so we need to allocate a page table
+ // for the next level.
+ //
+ TranslationTable = AllocatePages (1);
+ if (TranslationTable == NULL) {
+ return EFI_OUT_OF_RESOURCES;
}
- // Get the address corresponding at this entry
- BlockEntryAddress = RegionStart;
- BlockEntryAddress = BlockEntryAddress >> TT_ADDRESS_OFFSET_AT_LEVEL(IndexLevel);
- // Shift back to right to set zero before the effective address
- BlockEntryAddress = BlockEntryAddress << TT_ADDRESS_OFFSET_AT_LEVEL(IndexLevel);
-
- // Set the correct entry type for the next page level
- if ((IndexLevel + 1) == 3) {
- Attributes |= TT_TYPE_BLOCK_ENTRY_LEVEL3;
+ if ((*Entry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY) {
+ //
+ // We are splitting an existing block entry, so we have to populate
+ // the new table with the attributes of the block entry it replaces.
+ //
+ Status = UpdateRegionMappingRec (
+ RegionStart & ~BlockMask,
+ (RegionStart | BlockMask) + 1,
+ *Entry & TT_ATTRIBUTES_MASK,
+ 0,
+ TranslationTable,
+ Level + 1);
+ if (EFI_ERROR (Status)) {
+ return Status;
+ }
} else {
- Attributes |= TT_TYPE_BLOCK_ENTRY;
+ ZeroMem (TranslationTable, EFI_PAGE_SIZE);
}
+ } else {
+ TranslationTable = (VOID *)(UINTN)(*Entry & TT_ADDRESS_MASK_BLOCK_ENTRY);
+ }
- // Create a new translation table
- TranslationTable = AllocatePages (1);
- if (TranslationTable == NULL) {
- return NULL;
- }
-
- // Populate the newly created lower level table
- SubTableBlockEntry = TranslationTable;
- for (Index = 0; Index < TT_ENTRY_COUNT; Index++) {
- *SubTableBlockEntry = Attributes | (BlockEntryAddress + (Index << TT_ADDRESS_OFFSET_AT_LEVEL(IndexLevel + 1)));
- SubTableBlockEntry++;
- }
+ //
+ // Recurse to the next level
+ //
+ Status = UpdateRegionMappingRec (
+ RegionStart,
+ BlockEnd,
+ AttributeSetMask,
+ AttributeClearMask,
+ TranslationTable,
+ Level + 1);
+ if (EFI_ERROR (Status)) {
+ return Status;
+ }
- // Fill the BlockEntry with the new TranslationTable
- ReplaceLiveEntry (BlockEntry,
- (UINTN)TranslationTable | TableAttributes | TT_TYPE_TABLE_ENTRY,
- RegionStart);
+ if ((*Entry & TT_TYPE_MASK) != TT_TYPE_TABLE_ENTRY) {
+ ReplaceTableEntry (Entry,
+ (UINT64)TranslationTable | TT_TYPE_TABLE_ENTRY,
+ RegionStart,
+ (*Entry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY);
}
} else {
- if (IndexLevel != PageLevel) {
- //
- // Case when we have an Invalid Entry and we are at a page level above of the one targetted.
- //
+ EntryValue = (*Entry & AttributeClearMask) | AttributeSetMask;
+ EntryValue |= RegionStart;
+ EntryValue |= (Level == 3) ? TT_TYPE_BLOCK_ENTRY_LEVEL3
+ : TT_TYPE_BLOCK_ENTRY;
- // Create a new translation table
- TranslationTable = AllocatePages (1);
- if (TranslationTable == NULL) {
- return NULL;
- }
-
- ZeroMem (TranslationTable, TT_ENTRY_COUNT * sizeof(UINT64));
-
- // Fill the new BlockEntry with the TranslationTable
- *BlockEntry = ((UINTN)TranslationTable & TT_ADDRESS_MASK_DESCRIPTION_TABLE) | TT_TYPE_TABLE_ENTRY;
- }
+ ReplaceTableEntry (Entry, EntryValue, RegionStart, FALSE);
}
}
-
- // Expose the found PageLevel to the caller
- *TableLevel = PageLevel;
-
- // Now, we have the Table Level we can get the Block Size associated to this table
- *BlockEntrySize = TT_BLOCK_ENTRY_SIZE_AT_LEVEL (PageLevel);
-
- // The last block of the root table depends on the number of entry in this table,
- // otherwise it is always the (TT_ENTRY_COUNT - 1)th entry in the table.
- *LastBlockEntry = TT_LAST_BLOCK_ADDRESS(TranslationTable,
- (PageLevel == RootTableLevel) ? RootTableEntryCount : TT_ENTRY_COUNT);
-
- return BlockEntry;
+ return EFI_SUCCESS;
}
STATIC
EFI_STATUS
UpdateRegionMapping (
- IN UINT64 *RootTable,
- IN UINT64 RegionStart,
- IN UINT64 RegionLength,
- IN UINT64 Attributes,
- IN UINT64 BlockEntryMask
+ IN UINT64 RegionStart,
+ IN UINT64 RegionSize,
+ IN UINT64 AttributeSetMask,
+ IN UINT64 AttributeClearMask
)
{
- UINT32 Type;
- UINT64 *BlockEntry;
- UINT64 *LastBlockEntry;
- UINT64 BlockEntrySize;
- UINTN TableLevel;
+ UINTN RootTableLevel;
+ UINTN T0SZ;
- // Ensure the Length is aligned on 4KB boundary
- if ((RegionLength == 0) || ((RegionLength & (SIZE_4KB - 1)) != 0)) {
- ASSERT_EFI_ERROR (EFI_INVALID_PARAMETER);
+ if ((RegionStart & EFI_PAGE_MASK) != 0 || (RegionSize & EFI_PAGE_MASK) != 0) {
return EFI_INVALID_PARAMETER;
}
- do {
- // Get the first Block Entry that matches the Virtual Address and also the information on the Table Descriptor
- // such as the size of the Block Entry and the address of the last BlockEntry of the Table Descriptor
- BlockEntrySize = RegionLength;
- BlockEntry = GetBlockEntryListFromAddress (RootTable, RegionStart, &TableLevel, &BlockEntrySize, &LastBlockEntry);
- if (BlockEntry == NULL) {
- // GetBlockEntryListFromAddress() return NULL when it fails to allocate new pages from the Translation Tables
- return EFI_OUT_OF_RESOURCES;
- }
+ T0SZ = ArmGetTCR () & TCR_T0SZ_MASK;
+ GetRootTranslationTableInfo (T0SZ, &RootTableLevel, NULL);
- if (TableLevel != 3) {
- Type = TT_TYPE_BLOCK_ENTRY;
- } else {
- Type = TT_TYPE_BLOCK_ENTRY_LEVEL3;
- }
-
- do {
- // Fill the Block Entry with attribute and output block address
- *BlockEntry &= BlockEntryMask;
- *BlockEntry |= (RegionStart & TT_ADDRESS_MASK_BLOCK_ENTRY) | Attributes | Type;
-
- ArmUpdateTranslationTableEntry (BlockEntry, (VOID *)RegionStart);
-
- // Go to the next BlockEntry
- RegionStart += BlockEntrySize;
- RegionLength -= BlockEntrySize;
- BlockEntry++;
-
- // Break the inner loop when next block is a table
- // Rerun GetBlockEntryListFromAddress to avoid page table memory leak
- if (TableLevel != 3 && BlockEntry <= LastBlockEntry &&
- (*BlockEntry & TT_TYPE_MASK) == TT_TYPE_TABLE_ENTRY) {
- break;
- }
- } while ((RegionLength >= BlockEntrySize) && (BlockEntry <= LastBlockEntry));
- } while (RegionLength != 0);
-
- return EFI_SUCCESS;
+ return UpdateRegionMappingRec (RegionStart, RegionStart + RegionSize,
+ AttributeSetMask, AttributeClearMask, ArmGetTTBR0BaseAddress (),
+ RootTableLevel);
}
STATIC
@@ -398,7 +303,6 @@ FillTranslationTable (
)
{
return UpdateRegionMapping (
- RootTable,
MemoryRegion->VirtualBase,
MemoryRegion->Length,
ArmMemoryAttributeToPageAttribute (MemoryRegion->Attributes) | TT_AF,
@@ -455,8 +359,6 @@ ArmSetMemoryAttributes (
IN UINT64 Attributes
)
{
- EFI_STATUS Status;
- UINT64 *TranslationTable;
UINT64 PageAttributes;
UINT64 PageAttributeMask;
@@ -473,19 +375,11 @@ ArmSetMemoryAttributes (
TT_PXN_MASK | TT_XN_MASK);
}
- TranslationTable = ArmGetTTBR0BaseAddress ();
-
- Status = UpdateRegionMapping (
- TranslationTable,
+ return UpdateRegionMapping (
BaseAddress,
Length,
PageAttributes,
PageAttributeMask);
- if (EFI_ERROR (Status)) {
- return Status;
- }
-
- return EFI_SUCCESS;
}
STATIC
@@ -497,17 +391,7 @@ SetMemoryRegionAttribute (
IN UINT64 BlockEntryMask
)
{
- EFI_STATUS Status;
- UINT64 *RootTable;
-
- RootTable = ArmGetTTBR0BaseAddress ();
-
- Status = UpdateRegionMapping (RootTable, BaseAddress, Length, Attributes, BlockEntryMask);
- if (EFI_ERROR (Status)) {
- return Status;
- }
-
- return EFI_SUCCESS;
+ return UpdateRegionMapping (BaseAddress, Length, Attributes, BlockEntryMask);
}
EFI_STATUS
--
2.17.1
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