[edk2-devel] [PATCH v5 16/38] MdePkg/BasePeCoffLib: Add API to keep track of relocation range
Ard Biesheuvel
ardb at kernel.org
Mon Mar 13 17:16:52 UTC 2023
Add a library call to obtain the start and end of the region covered by
relocation fixups. This will be used in a future patch to limit the
range of memory that needs to be remapped with read-write-execute
permissions at ExitBootServices() time.
Signed-off-by: Ard Biesheuvel <ardb at kernel.org>
---
MdePkg/Include/Library/PeCoffLib.h | 23 ++++++
MdePkg/Library/BasePeCoffLib/BasePeCoff.c | 82 +++++++++++++++++++-
2 files changed, 104 insertions(+), 1 deletion(-)
diff --git a/MdePkg/Include/Library/PeCoffLib.h b/MdePkg/Include/Library/PeCoffLib.h
index b45879453785..df2f7f5e5961 100644
--- a/MdePkg/Include/Library/PeCoffLib.h
+++ b/MdePkg/Include/Library/PeCoffLib.h
@@ -382,4 +382,27 @@ PeCoffLoaderUnloadImage (
IN OUT PE_COFF_LOADER_IMAGE_CONTEXT *ImageContext
);
+/**
+ Retrieve the range subject to relocation fixups from the recorded fixup data
+ of a runtime image
+
+ @param ImageBase The base address of a PE/COFF image that has been loaded
+ and relocated into system memory.
+ @param ImageSize The size, in bytes, of the PE/COFF image.
+ @param RelocationData A pointer to the relocation data that was collected when the
+ PE/COFF image was relocated using PeCoffLoaderRelocateImage().
+ @param[out] RelocationRangeMin The start of the relocated range.
+ @param[out] RelocationRangeMax The end of the relocated range.
+
+**/
+VOID
+EFIAPI
+PeCoffLoaderGetRelocationRange (
+ IN PHYSICAL_ADDRESS ImageBase,
+ IN UINTN ImageSize,
+ IN VOID *RelocationData,
+ OUT PHYSICAL_ADDRESS *RelocationRangeMin,
+ OUT PHYSICAL_ADDRESS *RelocationRangeMax
+ );
+
#endif
diff --git a/MdePkg/Library/BasePeCoffLib/BasePeCoff.c b/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
index 97a8aaf8c73d..31e1f2035963 100644
--- a/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
+++ b/MdePkg/Library/BasePeCoffLib/BasePeCoff.c
@@ -936,6 +936,8 @@ PeCoffLoaderRelocateImage (
PHYSICAL_ADDRESS BaseAddress;
UINT32 NumberOfRvaAndSizes;
UINT32 TeStrippedOffset;
+ PHYSICAL_ADDRESS *RelocRangeStart;
+ PHYSICAL_ADDRESS *RelocRangeEnd;
ASSERT (ImageContext != NULL);
@@ -1043,6 +1045,21 @@ PeCoffLoaderRelocateImage (
// Run the relocation information and apply the fixups
//
FixupData = ImageContext->FixupData;
+ if (FixupData != NULL) {
+ FixupData = ALIGN_POINTER (FixupData, sizeof (PHYSICAL_ADDRESS));
+
+ //
+ // Use the first two UINT64s in the fixup data to keep track of the start
+ // and end of the region that is subject to relocation fixups.
+ //
+ RelocRangeStart = (PHYSICAL_ADDRESS *)FixupData;
+ RelocRangeEnd = RelocRangeStart + 1;
+ FixupData += 2 * sizeof (PHYSICAL_ADDRESS);
+
+ *RelocRangeStart = MAX_UINT64;
+ *RelocRangeEnd = 0;
+ }
+
while ((UINTN)RelocBase < (UINTN)RelocBaseEnd) {
Reloc = (UINT16 *)((CHAR8 *)RelocBase + sizeof (EFI_IMAGE_BASE_RELOCATION));
//
@@ -1070,6 +1087,14 @@ PeCoffLoaderRelocateImage (
return RETURN_LOAD_ERROR;
}
+ //
+ // Capture this page in the recorded relocation range
+ //
+ if (FixupData != NULL) {
+ *RelocRangeStart = MIN (*RelocRangeStart, (UINTN)FixupBase);
+ *RelocRangeEnd = MAX (*RelocRangeEnd, (UINTN)FixupBase + SIZE_4KB);
+ }
+
//
// Run this relocation record
//
@@ -1470,6 +1495,9 @@ PeCoffLoaderLoadImage (
//
ImageContext->FixupData = NULL;
+ // Add two UINT64s at the start to carry the min/max of the relocated range
+ ImageContext->FixupDataSize += 2 * sizeof (PHYSICAL_ADDRESS);
+
//
// Load the Codeview information if present
//
@@ -1824,7 +1852,8 @@ PeCoffLoaderRelocateImageForRuntime (
// by code will not be fixed up, since that would set them back to
// defaults.
//
- FixupData = RelocationData;
+ FixupData = ALIGN_POINTER (RelocationData, sizeof (PHYSICAL_ADDRESS));
+ FixupData += 2 * sizeof (PHYSICAL_ADDRESS);
RelocBaseOrig = RelocBase;
while ((UINTN)RelocBase < (UINTN)RelocBaseEnd) {
//
@@ -1994,3 +2023,54 @@ PeCoffLoaderUnloadImage (
PeCoffLoaderUnloadImageExtraAction (ImageContext);
return RETURN_SUCCESS;
}
+
+/**
+ Retrieve the range subject to relocation fixups from the recorded fixup data
+ of a runtime image
+
+ @param ImageBase The base address of a PE/COFF image that has been loaded
+ and relocated into system memory.
+ @param ImageSize The size, in bytes, of the PE/COFF image.
+ @param RelocationData A pointer to the relocation data that was collected when the
+ PE/COFF image was relocated using PeCoffLoaderRelocateImage().
+ @param[out] RelocationRangeMin The start of the relocated range.
+ @param[out] RelocationRangeMax The end of the relocated range.
+
+**/
+VOID
+EFIAPI
+PeCoffLoaderGetRelocationRange (
+ IN PHYSICAL_ADDRESS ImageBase,
+ IN UINTN ImageSize,
+ IN VOID *RelocationData,
+ OUT PHYSICAL_ADDRESS *RelocationRangeMin,
+ OUT PHYSICAL_ADDRESS *RelocationRangeMax
+ )
+{
+ PHYSICAL_ADDRESS *FixupData;
+
+ if ((RelocationData == NULL) || (ImageBase == 0x0)) {
+ return;
+ }
+
+ FixupData = ALIGN_POINTER (RelocationData, sizeof (PHYSICAL_ADDRESS));
+
+ if ((FixupData[0] == MAX_UINT64) && (FixupData[1] == 0)) {
+ // No fixups recorded
+ *RelocationRangeMin = ImageBase;
+ *RelocationRangeMax = ImageBase;
+ return;
+ }
+
+ if ((FixupData[0] < ImageBase) ||
+ (FixupData[1] > (ImageBase + ImageSize)))
+ {
+ ASSERT (FALSE);
+ *RelocationRangeMin = ImageBase;
+ *RelocationRangeMax = ImageBase + ImageSize;
+ return;
+ }
+
+ *RelocationRangeMin = FixupData[0];
+ *RelocationRangeMax = FixupData[1];
+}
--
2.39.2
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