Add CPU MP Debug Protocol

UefiCpuPkg/CpuDxe/CpuMp.c

@@ -625,7 +625,6 @@ InitializeExceptionStackSwitchHandlers (
 
   MpInitLibWhoAmI (&Index);
   SwitchStackData = (EXCEPTION_STACK_SWITCH_CONTEXT *)Buffer;
-
   //
   // This may be called twice for each Cpu. Only run InitializeSeparateExceptionStacks
   // if this is the first call or the first call failed because of size too small.
@@ -709,7 +708,6 @@ InitializeMpExceptionStackSwitchHandlers (
       ASSERT (SwitchStackData[Index].Status == EFI_SUCCESS);
     }
   }
-
   FreePool (SwitchStackData);
 }
 

UefiCpuPkg/Include/Library/MpInitLib.h

@@ -378,4 +378,25 @@ MpInitLibStartupAllCPUs (
   IN  VOID              *ProcedureArgument      OPTIONAL
   );
 
+// MU_CHANGE START: Support for protocol for reporting multi-processor debug info
+
+/**
+  Add CPU_MP_DEBUG_PROTOCOL entry to the global list
+
+  @param[in]  StackBuffer      Start of AP stack buffer
+  @param[in]  StackSize        Size of the stack
+  @param[in]  CpuNumber        AP CPU number
+  @param[in]  IsSwitchStack    If the input buffer is the CPU switch stack
+**/
+VOID
+EFIAPI
+AppendCpuMpDebugProtocolEntry (
+  UINTN    StackBuffer,
+  UINTN    StackSize,
+  UINTN    CpuNumber,
+  BOOLEAN  IsSwitchStack
+  );
+
+// MU_CHANGE END
+
 #endif

UefiCpuPkg/Include/Protocol/CpuMpDebug.h

@@ -0,0 +1,31 @@
+/** @file -- CpuMpDebug.h
+
+This protocol provides debug access to AP buffer information for validation and testing.
+
+Copyright (c) Microsoft Corporation. All rights reserved.
+SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef __CPU_MP_DEBUG_PROTOCOL__
+#define __CPU_MP_DEBUG_PROTOCOL__
+
+#define CPU_MP_DEBUG_PROTOCOL_GUID \
+  { \
+    0xce05eb65, 0x9416, 0x4197, {0x98, 0x4b, 0xa2, 0x8b, 0x62, 0x9c, 0x64, 0x4d } \
+  }
+
+#define CPU_MP_DEBUG_SIGNATURE  SIGNATURE_32 ('C','M','P','S')
+
+typedef struct _CPU_MP_DEBUG_PROTOCOL {
+  UINT32        Signature;
+  UINTN         ApStackBuffer;
+  UINTN         ApStackSize;
+  UINTN         CpuNumber;
+  BOOLEAN       IsSwitchStack;
+  LIST_ENTRY    Link;
+} CPU_MP_DEBUG_PROTOCOL;
+
+extern EFI_GUID  gCpuMpDebugProtocolGuid;
+
+#endif

UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf

@@ -61,6 +61,7 @@
 [Protocols]
   gEfiTimerArchProtocolGuid                     ## SOMETIMES_CONSUMES
   gEfiMemoryAttributeProtocolGuid               ## CONSUMES ## MU_CHANGE
+  gCpuMpDebugProtocolGuid                       ## PRODUCES ## MU_CHANGE
 
 [Guids]
   gEfiEventExitBootServicesGuid                 ## CONSUMES  ## Event

UefiCpuPkg/Library/MpInitLib/DxeMpLib.c

@@ -19,6 +19,19 @@
 #include <Protocol/Timer.h>
 
 #include <Library/DxeMemoryProtectionHobLib.h> // MU_CHANGE
+// MU_CHANGE: Add protocol for reporting multi-processor debug info
+#include <Protocol/CpuMpDebug.h>
+CPU_MP_DEBUG_PROTOCOL  mCpuMpDebugProtocol = {
+  CPU_MP_DEBUG_SIGNATURE,
+  0,
+  0,
+  0,
+  FALSE,
+  INITIALIZE_LIST_HEAD_VARIABLE (mCpuMpDebugProtocol.Link)
+};
+
+// MU_CHANGE END
+
 #define  AP_SAFE_STACK_SIZE  128
 
 CPU_MP_DATA       *mCpuMpData                  = NULL;
@@ -34,6 +47,65 @@ volatile UINT32   mNumberToFinish = 0;
 // Begin wakeup buffer allocation below 0x88000
 //
 STATIC EFI_PHYSICAL_ADDRESS  mSevEsDxeWakeupBuffer = 0x88000;
+// MU_CHANGE START: Install protocol for reporting multi-processor debug info
+
+/**
+  Add CPU_MP_DEBUG_PROTOCOL entry to the global list
+
+  @param[in]  StackBuffer      Start of AP stack buffer
+  @param[in]  StackSize        Size of the stack
+  @param[in]  CpuNumber        AP CPU number
+  @param[in]  IsSwitchStack    If the input buffer is the CPU switch stack
+**/
+VOID
+EFIAPI
+AppendCpuMpDebugProtocolEntry (
+  UINTN    StackBuffer,
+  UINTN    StackSize,
+  UINTN    CpuNumber,
+  BOOLEAN  IsSwitchStack
+  )
+{
+  CPU_MP_DEBUG_PROTOCOL  *Entry;
+
+  Entry = AllocatePool (sizeof (CPU_MP_DEBUG_PROTOCOL));
+  if (Entry == NULL) {
+    DEBUG ((DEBUG_ERROR, "%a - Failed to allocate memory!\n", __FUNCTION__));
+    return;
+  }
+
+  Entry->Signature     = CPU_MP_DEBUG_SIGNATURE;
+  Entry->ApStackBuffer = StackBuffer;
+  Entry->ApStackSize   = StackSize;
+  Entry->CpuNumber     = CpuNumber;
+  Entry->IsSwitchStack = IsSwitchStack;
+  InsertTailList (&mCpuMpDebugProtocol.Link, &Entry->Link);
+}
+
+// MU_CHANGE START: Install protocol for reporting multi-processor debug info
+
+/**
+  Install the CPU MP debug protocol
+**/
+STATIC
+VOID
+InstallCpuMpDebugProtocol (
+  VOID
+  )
+{
+  EFI_HANDLE  MpDebugHandle = NULL;
+  EFI_STATUS  Status;
+
+  Status = gBS->InstallMultipleProtocolInterfaces (
+                  &MpDebugHandle,
+                  &gCpuMpDebugProtocolGuid,
+                  &mCpuMpDebugProtocol,
+                  NULL
+                  );
+  DEBUG ((DEBUG_INFO, "Installed gCpuMpDebugProtocolGuid - Status: %r\n", Status));
+}
+
+// MU_CHANGE END
 
 /**
   Enable Debug Agent to support source debugging on AP function.
@@ -519,16 +591,35 @@ InitMpGlobalData (
                       MemDesc.Attributes | EFI_MEMORY_RP
                       );
       ASSERT_EFI_ERROR (Status);
-
+      AppendCpuMpDebugProtocolEntry (StackBase, CpuMpData->CpuApStackSize, Index, FALSE); // MU_CHANGE
       DEBUG ((
         DEBUG_INFO,
         "Stack Guard set at %lx [cpu%lu]!\n",
         (UINT64)StackBase,
         (UINT64)Index
         ));
     }
+
+    InstallCpuMpDebugProtocol (); // MU_CHANGE
+  }
+  // MU_CHANGE START: Add the Debug Protocol in the case that CpuStackGuard is not active
+  else {
+    CpuInfoInHob = (CPU_INFO_IN_HOB *)(UINTN)CpuMpData->CpuInfoInHob;
+    for (Index = 0; Index < CpuMpData->CpuCount; ++Index) {
+      if ((CpuInfoInHob != NULL) && (CpuInfoInHob[Index].ApTopOfStack != 0)) {
+        StackBase = (UINTN)CpuInfoInHob[Index].ApTopOfStack - CpuMpData->CpuApStackSize;
+      } else {
+        StackBase = CpuMpData->Buffer + Index * CpuMpData->CpuApStackSize;
+      }
+
+      AppendCpuMpDebugProtocolEntry (StackBase, CpuMpData->CpuApStackSize, Index, FALSE);
+    }
+
+    InstallCpuMpDebugProtocol ();
   }
 
+  // MU_CHANGE END
+
   //
   // Avoid APs access invalid buffer data which allocated by BootServices,
   // so we will allocate reserved data for AP loop code. We also need to

UefiCpuPkg/Library/MpInitLib/PeiMpLib.c

@@ -765,3 +765,27 @@ PlatformShadowMicrocode (
 
   return EFI_SUCCESS;
 }
+
+// MU_CHANGE START: Support for protocol for reporting multi-processor debug info
+
+/**
+  Add CPU_MP_DEBUG_PROTOCOL entry to the global list
+
+  @param[in]  StackBuffer      Start of AP stack buffer
+  @param[in]  StackSize        Size of the stack
+  @param[in]  CpuNumber        AP CPU number
+  @param[in]  IsSwitchStack    If the input buffer is the CPU switch stack
+**/
+VOID
+EFIAPI
+AppendCpuMpDebugProtocolEntry (
+  UINTN    StackBuffer,
+  UINTN    StackSize,
+  UINTN    CpuNumber,
+  BOOLEAN  IsSwitchStack
+  )
+{
+  return;
+}
+
+// MU_CHANGE END

UefiCpuPkg/UefiCpuPkg.dec

@@ -85,11 +85,17 @@
 
   ## Include/Protocol/SmMonitorInit.h
   gEfiSmMonitorInitProtocolGuid  = { 0x228f344d, 0xb3de, 0x43bb, { 0xa4, 0xd7, 0xea, 0x20, 0xb, 0x1b, 0x14, 0x82 }}
+
   #MSCHANGE - Add support for testing Smm protections
   #
   ## Include/Protocol/SmmExceptionTestProtocol.h
   gSmmExceptionTestProtocolGuid   = { 0xb76383a1, 0x0e70, 0x4a3f, { 0x86, 0xb4, 0xc6, 0x13, 0x4c, 0x8e, 0x57, 0x23 }}
 
+  # MU_CHANGE - Add protocol for reporting multi-processor debug info
+  #
+  ## Include/Protocol/CpuMpDebug.h
+  gCpuMpDebugProtocolGuid = { 0xce05eb65, 0x9416, 0x4197, {0x98, 0x4b, 0xa2, 0x8b, 0x62, 0x9c, 0x64, 0x4d }}
+
 #
 # [Error.gUefiCpuPkgTokenSpaceGuid]
 #   0x80000001 | Invalid value provided.
@@ -201,6 +207,7 @@
   ## Size of teh area of memory where the SEV-ES work area block lives.
   # @Prompt Configure the SEV-ES work area base
   gUefiCpuPkgTokenSpaceGuid.PcdSevEsWorkAreaSize|0x0|UINT32|0x30002006
+
   ## MS_CHANGE
   ## If TRUE, the default Cpu Exception Handler in SMM will reboot 
   # This handler state can be changed by using the Exception Test Protocol