Implement binary patching in OcAcpiLib

Include/Library/OcAcpiLib.h

@@ -36,6 +36,9 @@ typedef struct {
 
 #pragma pack(pop)
 
+//
+// Main ACPI context describing current tableset worked on.
+//
 typedef struct {
   //
   // Pointer to original RSDP table.
@@ -50,6 +53,14 @@ typedef struct {
   //
   OC_ACPI_6_2_EXTENDED_SYSTEM_DESCRIPTION_TABLE  *Xsdt;
   //
+  // Pointer to active FADT table.
+  //
+  EFI_ACPI_6_2_FIXED_ACPI_DESCRIPTION_TABLE      *Fadt;
+  //
+  // Pointer to active DSDT table.
+  //
+  EFI_ACPI_DESCRIPTION_HEADER                    *Dsdt;
+  //
   // Current list of tables allocated from heap.
   //
   EFI_ACPI_COMMON_HEADER                         **Tables;
@@ -63,6 +74,48 @@ typedef struct {
   UINT32                                         AllocatedTables;
 } OC_ACPI_CONTEXT;
 
+//
+// ACPI patch structure.
+//
+typedef struct {
+  //
+  // Find bytes.
+  //
+  CONST UINT8  *Find;
+  //
+  // Replace bytes.
+  //
+  CONST UINT8  *Replace;
+  //
+  // Find mask or NULL.
+  //
+  CONST UINT8  *Mask;
+  //
+  // Patch size.
+  //
+  UINT32       Size;
+  //
+  // Replace count or 0 for all.
+  //
+  UINT32       Count;
+  //
+  // Skip count or 0 to start from 1 match.
+  //
+  UINT32       Skip;
+  //
+  // ACPI Table signature or 0.
+  //
+  UINT32       TableSignature;
+  //
+  // ACPI Table length or 0.
+  //
+  UINT32       TableLength;
+  //
+  // ACPI Table Id or 0.
+  //
+  UINT64       OemTableId;
+} OC_ACPI_PATCH;
+
 /** Find ACPI System Tables for later table configuration.
 
   @param Context  ACPI library context.
@@ -94,7 +147,7 @@ AcpiApplyContext (
 
 /** Drop one ACPI table.
 
-  @param Context     ACPI library context
+  @param Context     ACPI library context.
   @param Signature   Table signature or 0.
   @param Length      Table length or 0.
   @param OemTableId  Table Id or 0.
@@ -109,7 +162,7 @@ AcpiDropTable (
 
 /** Install one ACPI table. For DSDT this performs table replacement.
 
-  @param Context     ACPI library context
+  @param Context     ACPI library context.
   @param Data        Table data.
   @param Length      Table length.
 **/
@@ -122,11 +175,22 @@ AcpiInsertTable (
 
 /** Normalise ACPI headers to contain 7-bit ASCII.
 
-  @param Context     ACPI library context
+  @param Context     ACPI library context.
 **/
 VOID
 AcpiNormalizeHeaders (
   IN OUT OC_ACPI_CONTEXT  *Context
   );
 
+/** Patch ACPI tables.
+
+  @param Context     ACPI library context.
+  @param Patch       ACPI patch.
+**/
+EFI_STATUS
+AcpiApplyPatch (
+  IN OUT OC_ACPI_CONTEXT  *Context,
+  IN     OC_ACPI_PATCH    *Patch
+  );
+
 #endif // OC_ACPI_LIB_H

Include/Library/OcMiscLib.h

@@ -12,8 +12,10 @@
   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 **/
 
-#ifndef OC_MISC_LIB_H_
-#define OC_MISC_LIB_H_
+#ifndef OC_MISC_LIB_H
+#define OC_MISC_LIB_H
+
+#include <Uefi.h>
 
 // PLATFORM_DATA_HEADER
 typedef struct {
@@ -166,4 +168,26 @@ WaitForKeyPress (
   CONST CHAR16 *Message
   );
 
-#endif // OC_MISC_LIB_H_
+INT32
+FindPattern (
+  IN CONST UINT8   *Pattern,
+  IN CONST UINT8   *PatternMask OPTIONAL,
+  IN CONST UINT32  PatternSize,
+  IN CONST UINT8   *Data,
+  IN UINT32        DataSize,
+  IN INT32         DataOff
+  );
+
+UINT32
+ApplyPatch (
+  IN CONST UINT8   *Pattern,
+  IN CONST UINT8   *PatternMask OPTIONAL,
+  IN CONST UINT32  PatternSize,
+  IN CONST UINT8   *Replace,
+  IN UINT8         *Data,
+  IN UINT32        DataSize,
+  IN UINT32        Count,
+  IN UINT32        Skip
+  );
+
+#endif // OC_MISC_LIB_H

Library/OcAcpiLib/OcAcpiLib.c

@@ -19,6 +19,7 @@
 #include <Library/MemoryAllocationLib.h>
 #include <Library/UefiLib.h>
 #include <Library/UefiBootServicesTableLib.h>
+#include <Library/OcMiscLib.h>
 
 #include <IndustryStandard/AcpiAml.h>
 #include <IndustryStandard/Acpi62.h>
@@ -202,9 +203,11 @@ AcpiInitContext (
       ? Context->Xsdt->Tables[Index] : (UINT64) Context->Rsdt->Tables[Index]);
 
     //
-    // Skip NULL table entries if any.
+    // Skip NULL table entries, DSDT, and RSDP if any.
     //
-    if (Context->Tables[DstIndex] == NULL) {
+    if (Context->Tables[DstIndex] == NULL
+      || Context->Tables[DstIndex]->Signature == EFI_ACPI_6_2_DIFFERENTIATED_SYSTEM_DESCRIPTION_TABLE_SIGNATURE
+      || *(UINT64 *) Context->Tables[DstIndex] == EFI_ACPI_6_2_ROOT_SYSTEM_DESCRIPTION_POINTER_SIGNATURE) {
       continue;
     }
 
@@ -216,6 +219,16 @@ AcpiInitContext (
       Index
       ));
 
+    if (Context->Tables[DstIndex]->Signature == EFI_ACPI_6_2_FIXED_ACPI_DESCRIPTION_TABLE_SIGNATURE) {
+      Context->Fadt = (EFI_ACPI_6_2_FIXED_ACPI_DESCRIPTION_TABLE *) Context->Tables[DstIndex];
+
+      if (Context->Fadt->Header.Length >= OFFSET_OF (EFI_ACPI_6_2_FIXED_ACPI_DESCRIPTION_TABLE, XDsdt) + sizeof (Context->Fadt->XDsdt)) {
+        Context->Dsdt = (EFI_ACPI_DESCRIPTION_HEADER *)(UINTN) Context->Fadt->XDsdt;
+      } else {
+        Context->Dsdt = (EFI_ACPI_DESCRIPTION_HEADER *)(UINTN) Context->Fadt->Dsdt;
+      }
+    }
+
     ++DstIndex;
   }
 
@@ -224,6 +237,14 @@ AcpiInitContext (
     Context->NumberOfTables = DstIndex;
   }
 
+  if (Context->Fadt == NULL) {
+    DEBUG ((DEBUG_WARN, "Failed to find ACPI FADT table\n"));
+  }
+
+  if (Context->Dsdt == NULL) {
+    DEBUG ((DEBUG_WARN, "Failed to find ACPI DSDT table\n"));
+  }
+
   return EFI_SUCCESS;
 }
 
@@ -444,3 +465,111 @@ AcpiNormalizeHeaders (
     }
   }
 }
+
+EFI_STATUS
+AcpiApplyPatch (
+  IN OUT OC_ACPI_CONTEXT  *Context,
+  IN     OC_ACPI_PATCH    *Patch
+  )
+{
+  UINT32  Index;
+  UINT64  CurrOemTableId;
+  UINT32  ReplaceCount;
+
+  DEBUG ((DEBUG_INFO, "Applying %u byte ACPI patch skip %u, count %u\n", Patch->Size, Patch->Skip, Patch->Count));
+
+  if (Context->Dsdt != NULL
+    && (Patch->TableSignature == 0 || Patch->TableSignature == EFI_ACPI_6_2_DIFFERENTIATED_SYSTEM_DESCRIPTION_TABLE_SIGNATURE)
+    && (Patch->TableLength == 0 || Context->Dsdt->Length == Patch->TableLength)
+    && (Patch->OemTableId == 0 || Context->Dsdt->OemTableId == Patch->OemTableId)) {
+    DEBUG ((
+      DEBUG_INFO,
+      "Patching DSDT of %u bytes with %016Lx ID\n",
+      Patch->TableLength,
+      Patch->OemTableId
+      ));
+
+    ReplaceCount = ApplyPatch (
+      Patch->Find,
+      Patch->Mask,
+      Patch->Size,
+      Patch->Replace,
+      (UINT8 *) Context->Dsdt,
+      Context->Dsdt->Length,
+      Patch->Count,
+      Patch->Skip
+      );
+
+    (VOID) ReplaceCount;
+    DEBUG ((DEBUG_INFO, "Replaced %u matches out of requested %u in DSDT\n", ReplaceCount, Patch->Count));
+
+    if (ReplaceCount > 0) {
+      Context->Dsdt->Checksum = 0;
+      Context->Dsdt->Checksum = CalculateCheckSum8 (
+        (UINT8 *) Context->Dsdt,
+        Context->Dsdt->Length
+        );
+
+      DEBUG ((
+        DEBUG_INFO,
+        "Refreshed DSDT checksum to %02x\n",
+        Context->Dsdt->Checksum
+        ));
+    }
+  }
+
+  for (Index = 0; Index < Context->NumberOfTables; ++Index) {
+    if ((Patch->TableSignature == 0 || Context->Tables[Index]->Signature == Patch->TableSignature)
+      && (Patch->TableLength == 0 || Context->Tables[Index]->Length == Patch->TableLength)) {
+
+      if (Context->Tables[Index]->Length >= sizeof (EFI_ACPI_DESCRIPTION_HEADER)) {
+        CurrOemTableId = ((EFI_ACPI_DESCRIPTION_HEADER *) Context->Tables[Index])->OemTableId;
+      } else {
+        CurrOemTableId = 0;
+      }
+
+      if (Patch->OemTableId != 0 && CurrOemTableId != Patch->OemTableId) {
+        continue;
+      }
+
+      DEBUG ((
+        DEBUG_INFO,
+        "Patching table %08x of %u bytes with %016Lx ID at index %u\n",
+        Context->Tables[Index]->Signature,
+        Context->Tables[Index]->Length,
+        CurrOemTableId,
+        Index
+        ));
+
+      ReplaceCount = ApplyPatch (
+        Patch->Find,
+        Patch->Mask,
+        Patch->Size,
+        Patch->Replace,
+        (UINT8 *) Context->Tables[Index],
+        Context->Tables[Index]->Length,
+        Patch->Count,
+        Patch->Skip
+        );
+
+      (VOID) ReplaceCount;
+      DEBUG ((DEBUG_INFO, "Replaced %u matches out of requested %u\n", ReplaceCount, Patch->Count));
+
+      if (ReplaceCount > 0 && Context->Tables[Index]->Length >= sizeof (EFI_ACPI_DESCRIPTION_HEADER)) {
+        ((EFI_ACPI_DESCRIPTION_HEADER *)Context->Tables[Index])->Checksum = 0;
+        ((EFI_ACPI_DESCRIPTION_HEADER *)Context->Tables[Index])->Checksum = CalculateCheckSum8 (
+          (UINT8 *) Context->Tables[Index],
+          Context->Tables[Index]->Length
+          );
+
+        DEBUG ((
+          DEBUG_INFO,
+          "Refreshed checksum to %02x\n",
+          ((EFI_ACPI_DESCRIPTION_HEADER *)Context->Tables[Index])->Checksum
+          ));
+      }
+    }
+  }
+
+  return EFI_UNSUPPORTED;
+}

Library/OcAcpiLib/OcAcpiLib.inf

@@ -35,6 +35,7 @@
 
 [LibraryClasses]
   BaseLib
+  OcMiscLib
 
 [Guids]
   gEfiAcpi10TableGuid

Library/OcMiscLib/DataPatcher.c

+/** @file
+  Copyright (C) 2019, vit9696. All rights reserved.
+
+  All rights reserved.
+
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+
+#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
+#include <Library/DebugLib.h>
+#include <Library/OcMiscLib.h>
+
+INT32
+FindPattern (
+  IN CONST UINT8   *Pattern,
+  IN CONST UINT8   *PatternMask OPTIONAL,
+  IN CONST UINT32  PatternSize,
+  IN CONST UINT8   *Data,
+  IN UINT32        DataSize,
+  IN INT32         DataOff
+  )
+{
+  BOOLEAN  Matches;
+  UINT32   Index;
+
+  if (PatternSize == 0 || DataSize == 0 || DataOff >= DataSize || DataSize - DataOff < PatternSize) {
+    return -1;
+  }
+
+  while (DataOff + PatternSize < DataSize) {
+    Matches = TRUE;
+    for (Index = 0; Index < PatternSize; ++Index) {
+      if ((PatternMask == NULL && Data[DataOff + Index] != Pattern[Index])
+      || (PatternMask != NULL && (Data[DataOff + Index] & PatternMask[Index]) != Pattern[Index])) {
+        Matches = FALSE;
+        break;
+      }
+    }
+
+    if (Matches) {
+      return DataOff;
+    }
+    ++DataOff;
+  }
+
+  return -1;
+}
+
+UINT32
+ApplyPatch (
+  IN CONST UINT8   *Pattern,
+  IN CONST UINT8   *PatternMask OPTIONAL,
+  IN CONST UINT32  PatternSize,
+  IN CONST UINT8   *Replace,
+  IN UINT8         *Data,
+  IN UINT32        DataSize,
+  IN UINT32        Count,
+  IN UINT32        Skip
+  )
+{
+  UINT32  ReplaceCount;
+  INT32   DataOff;
+
+  ReplaceCount = 0;
+  DataOff = 0;
+
+  do {
+    DataOff = FindPattern (Pattern, PatternMask, PatternSize, Data, DataSize, DataOff);
+
+    if (DataOff >= 0) {
+      //
+      // Skip this finding if requested.
+      //
+      if (Skip > 0) {
+        --Skip;
+        DataOff += PatternSize;
+        continue;
+      }
+
+      //
+      // Perform replacement.
+      //
+      CopyMem (&Data[DataOff], Replace, PatternSize);
+      ++ReplaceCount;
+      DataOff += PatternSize;
+
+      //
+      // Check replace count if requested.
+      //
+      if (Count > 0) {
+        --Count;
+        if (Count == 0) {
+          break;
+        }
+      }
+    }
+
+  } while (DataOff >= 0);
+
+  return ReplaceCount;
+}

Library/OcMiscLib/OcMiscLib.inf

@@ -48,6 +48,7 @@
 [Sources]
   Base64Decode.c
   ConvertDataToString.c
+  DataPatcher.c
   DebugHelp.c
   LegacyRegionLock.c
   LegacyRegionUnLock.c

Tests/AcpiTest/AcpiTest.c

@@ -65,6 +65,28 @@ UINT8 PatchedSsdt8[] = {
   0x47, 0x50, 0x45, 0x0A, 0x17
 };
 
+STATIC UINT8 HpetPatchFind[] = {'H', 'P', 'E', 'T'};
+STATIC UINT8 HpetPatchReplace[] = {'X', 'P', 'E', 'T'};
+STATIC UINT8 HpetPatchMask[] = {0xFF, 0xFF, 0xFF, 0xFF};
+STATIC
+OC_ACPI_PATCH
+HpetPatch = {
+  .Find    = HpetPatchFind,
+  .Replace = HpetPatchReplace,
+  .Mask    = HpetPatchMask,
+  .Size    = sizeof (HpetPatchFind),
+  //
+  // Replace only once.
+  //
+  .Count   = 1,
+  .Skip    = 0,
+  //
+  // Only patch DSDT.
+  //
+  .TableSignature = EFI_ACPI_6_2_DIFFERENTIATED_SYSTEM_DESCRIPTION_TABLE_SIGNATURE,
+  .TableLength = 0,
+  .OemTableId = 0
+};
 
 EFI_STATUS
 EFIAPI
@@ -85,6 +107,8 @@ TestAcpi (
 
     AcpiInsertTable (&Context, PatchedSsdt8, sizeof (PatchedSsdt8));
 
+    AcpiApplyPatch (&Context, &HpetPatch);
+
     AcpiApplyContext (&Context);
 
     AcpiFreeContext (&Context);