[PATCH v1 01/11] ShellPkg: acpiview: FADT: Validate global pointers before use

["Krzysztof Koch" <krzysztof.koch@arm.com>]

1. Check if the global pointer have been successfully updated before
they are later used to control the parsing logic in the FADT acpiview
parser.

2. Remove redundant forward function declarations by repositioning
blocks of code.

3. Allow silencing ACPI table content validation errors which do not
cause table parsing to fail.

Signed-off-by: Krzysztof Koch <krzysztof.koch@arm.com>
---

Changes can be seen at: https://github.com/KrzysztofKoch1/edk2/commit/49cc41430775fb93205e302590a7d31f080c3952

Notes:
    v1:
    - improve the logic in the parser [Krzysztof]

 ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.c | 131 ++++++++------------
 1 file changed, 51 insertions(+), 80 deletions(-)

diff --git a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.c b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.c
index cee7ee0770433da96d6042d2f5d687903f4b5495..600d3b16d7b22b61c1a1fd21ecb93f16c7f8fa1a 100644
--- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.c
+++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.c
@@ -1,7 +1,7 @@
 /** @file
   FADT table parser
 
-  Copyright (c) 2016 - 2018, ARM Limited. All rights reserved.
+  Copyright (c) 2016 - 2019, ARM Limited. All rights reserved.
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
   @par Reference(s):
@@ -12,6 +12,7 @@
 #include <Library/UefiLib.h>
 #include "AcpiParser.h"
 #include "AcpiTableParser.h"
+#include "AcpiView.h"
 
 // Local variables
 STATIC CONST UINT32* DsdtAddress;
@@ -46,7 +47,17 @@ EFIAPI
 ValidateFirmwareCtrl (
   IN UINT8* Ptr,
   IN VOID*  Context
-  );
+)
+{
+#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
+  if (*(UINT32*)Ptr != 0) {
+    IncrementErrorCount ();
+    Print (
+      L"\nERROR: Firmware Control must be zero for ARM platforms."
+    );
+  }
+#endif
+}
 
 /**
   This function validates the X_Firmware Control Field.
@@ -61,7 +72,17 @@ EFIAPI
 ValidateXFirmwareCtrl (
   IN UINT8* Ptr,
   IN VOID*  Context
-  );
+)
+{
+#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
+  if (*(UINT64*)Ptr != 0) {
+    IncrementErrorCount ();
+    Print (
+      L"\nERROR: X Firmware Control must be zero for ARM platforms."
+    );
+  }
+#endif
+}
 
 /**
   This function validates the flags.
@@ -76,7 +97,17 @@ EFIAPI
 ValidateFlags (
   IN UINT8* Ptr,
   IN VOID*  Context
-  );
+)
+{
+#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
+  if (((*(UINT32*)Ptr) & HW_REDUCED_ACPI) == 0) {
+    IncrementErrorCount ();
+    Print (
+      L"\nERROR: HW_REDUCED_ACPI flag must be set for ARM platforms."
+    );
+  }
+#endif
+}
 
 /**
   An ACPI_PARSER array describing the ACPI FADT Table.
@@ -142,81 +173,6 @@ STATIC CONST ACPI_PARSER FadtParser[] = {
   {L"Hypervisor VendorIdentity", 8, 268, L"%lx", NULL, NULL, NULL, NULL}
 };
 
-/**
-  This function validates the Firmware Control Field.
-
-  @param [in] Ptr     Pointer to the start of the field data.
-  @param [in] Context Pointer to context specific information e.g. this
-                      could be a pointer to the ACPI table header.
-**/
-STATIC
-VOID
-EFIAPI
-ValidateFirmwareCtrl (
-  IN UINT8* Ptr,
-  IN VOID*  Context
-)
-{
-#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
-  if (*(UINT32*)Ptr != 0) {
-    IncrementErrorCount ();
-    Print (
-      L"\nERROR: Firmware Control must be zero for ARM platforms."
-    );
-  }
-#endif
-}
-
-/**
-  This function validates the X_Firmware Control Field.
-
-  @param [in] Ptr     Pointer to the start of the field data.
-  @param [in] Context Pointer to context specific information e.g. this
-                      could be a pointer to the ACPI table header.
-**/
-STATIC
-VOID
-EFIAPI
-ValidateXFirmwareCtrl (
-  IN UINT8* Ptr,
-  IN VOID*  Context
-)
-{
-#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
-  if (*(UINT64*)Ptr != 0) {
-    IncrementErrorCount ();
-    Print (
-      L"\nERROR: X Firmware Control must be zero for ARM platforms."
-    );
-  }
-#endif
-}
-
-/**
-  This function validates the flags.
-
-  @param [in] Ptr     Pointer to the start of the field data.
-  @param [in] Context Pointer to context specific information e.g. this
-                      could be a pointer to the ACPI table header.
-**/
-STATIC
-VOID
-EFIAPI
-ValidateFlags (
-  IN UINT8* Ptr,
-  IN VOID*  Context
-)
-{
-#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
-  if (((*(UINT32*)Ptr) & HW_REDUCED_ACPI) == 0) {
-    IncrementErrorCount ();
-    Print (
-      L"\nERROR: HW_REDUCED_ACPI flag must be set for ARM platforms."
-    );
-  }
-#endif
-}
-
 /**
   This function parses the ACPI FADT table.
   This function parses the FADT table and optionally traces the ACPI table fields.
@@ -248,12 +204,27 @@ ParseAcpiFadt (
     PARSER_PARAMS (FadtParser)
     );
 
+  // Check if the values used to control the parsing logic have been
+  // successfully read.
+  if ((DsdtAddress == NULL)       ||
+      (FadtMinorRevision == NULL) ||
+      (X_DsdtAddress == NULL)) {
+    IncrementErrorCount ();
+    Print (
+      L"ERROR: Insufficient table length. AcpiTableLength = %d. " \
+        L"FADT parsing aborted.\n",
+      AcpiTableLength
+      );
+    return;
+  }
+
   if (Trace) {
     Print (L"\nSummary:\n");
     PrintFieldName (2, L"FADT Version");
     Print (L"%d.%d\n",  *AcpiHdrInfo.Revision, *FadtMinorRevision);
 
-    if (*GetAcpiXsdtHeaderInfo ()->OemTableId != *AcpiHdrInfo.OemTableId) {
+    if (GetConsistencyChecking () &&
+        (*GetAcpiXsdtHeaderInfo ()->OemTableId != *AcpiHdrInfo.OemTableId)) {
       IncrementErrorCount ();
       Print (L"ERROR: OEM Table Id does not match with RSDT/XSDT.\n");
     }
--
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'