StandaloneMmPkg/StandaloneMmHobLib: Remove HOB creation

According to the discussion in "StandaloneMmPkg: Fix HOB space and
heap space conflicted issue" [1], Standalone MM modules should be HOB
consumers where HOB is read-only. Therefore, this patch removes the
supported functions for HOB creation in the StandaloneMmHobLib.

[1] https://edk2.groups.io/g/devel/message/108333

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Cc: Oliver Smith-Denny <osde@linux.microsoft.com>
Signed-off-by: Nhi Pham <nhiphambka@gmail.com>

StandaloneMmPkg/Library/StandaloneMmHobLib/StandaloneMmHobLib.c

@@ -1,5 +1,5 @@
 /** @file
-  HOB Library implementation for Standalone MM Core.
+  HOB Library implementation for Standalone MM modules.
 
 Copyright (c) 2006 - 2014, Intel Corporation. All rights reserved.<BR>
 Copyright (c) 2017 - 2018, ARM Limited. All rights reserved.<BR>
@@ -250,48 +250,13 @@ GetBootModeHob (
   return HandOffHob->BootMode;
 }
 
-VOID *
-CreateHob (
-  IN  UINT16  HobType,
-  IN  UINT16  HobLength
-  )
-{
-  EFI_HOB_HANDOFF_INFO_TABLE  *HandOffHob;
-  EFI_HOB_GENERIC_HEADER      *HobEnd;
-  EFI_PHYSICAL_ADDRESS        FreeMemory;
-  VOID                        *Hob;
-
-  HandOffHob = GetHobList ();
-
-  HobLength = (UINT16)((HobLength + 0x7) & (~0x7));
-
-  FreeMemory = HandOffHob->EfiFreeMemoryTop - HandOffHob->EfiFreeMemoryBottom;
-
-  if (FreeMemory < HobLength) {
-    return NULL;
-  }
-
-  Hob                                        = (VOID *)(UINTN)HandOffHob->EfiEndOfHobList;
-  ((EFI_HOB_GENERIC_HEADER *)Hob)->HobType   = HobType;
-  ((EFI_HOB_GENERIC_HEADER *)Hob)->HobLength = HobLength;
-  ((EFI_HOB_GENERIC_HEADER *)Hob)->Reserved  = 0;
-
-  HobEnd                      = (EFI_HOB_GENERIC_HEADER *)((UINTN)Hob + HobLength);
-  HandOffHob->EfiEndOfHobList = (EFI_PHYSICAL_ADDRESS)(UINTN)HobEnd;
-
-  HobEnd->HobType   = EFI_HOB_TYPE_END_OF_HOB_LIST;
-  HobEnd->HobLength = sizeof (EFI_HOB_GENERIC_HEADER);
-  HobEnd->Reserved  = 0;
-  HobEnd++;
-  HandOffHob->EfiFreeMemoryBottom = (EFI_PHYSICAL_ADDRESS)(UINTN)HobEnd;
-
-  return Hob;
-}
-
 /**
   Builds a HOB for a loaded PE32 module.
 
   This function builds a HOB for a loaded PE32 module.
+  It can only be invoked by Standalone MM Core.
+  For Standalone MM drivers, it will ASSERT() since HOB is read only for Standalone MM drivers.
+
   If ModuleName is NULL, then ASSERT().
   If there is no additional space for HOB creation, then ASSERT().
 
@@ -310,33 +275,19 @@ BuildModuleHob (
   IN EFI_PHYSICAL_ADDRESS  EntryPoint
   )
 {
-  EFI_HOB_MEMORY_ALLOCATION_MODULE  *Hob;
-
-  ASSERT (
-    ((MemoryAllocationModule & (EFI_PAGE_SIZE - 1)) == 0) &&
-    ((ModuleLength & (EFI_PAGE_SIZE - 1)) == 0)
-    );
-
-  Hob = CreateHob (EFI_HOB_TYPE_MEMORY_ALLOCATION, sizeof (EFI_HOB_MEMORY_ALLOCATION_MODULE));
-
-  CopyGuid (&(Hob->MemoryAllocationHeader.Name), &gEfiHobMemoryAllocModuleGuid);
-  Hob->MemoryAllocationHeader.MemoryBaseAddress = MemoryAllocationModule;
-  Hob->MemoryAllocationHeader.MemoryLength      = ModuleLength;
-  Hob->MemoryAllocationHeader.MemoryType        = EfiBootServicesCode;
-
   //
-  // Zero the reserved space to match HOB spec
+  // HOB is read only for Standalone MM drivers
   //
-  ZeroMem (Hob->MemoryAllocationHeader.Reserved, sizeof (Hob->MemoryAllocationHeader.Reserved));
+  ASSERT (FALSE);
-
-  CopyGuid (&Hob->ModuleName, ModuleName);
-  Hob->EntryPoint = EntryPoint;
 }
 
 /**
   Builds a HOB that describes a chunk of system memory.
 
   This function builds a HOB that describes a chunk of system memory.
+  It can only be invoked by Standalone MM Core.
+  For Standalone MM drivers, it will ASSERT() since HOB is read only for Standalone MM drivers.
+
   If there is no additional space for HOB creation, then ASSERT().
 
   @param  ResourceType        The type of resource described by this HOB.
@@ -354,15 +305,10 @@ BuildResourceDescriptorHob (
   IN UINT64                       NumberOfBytes
   )
 {
-  EFI_HOB_RESOURCE_DESCRIPTOR  *Hob;
+  //
-
+  // HOB is read only for Standalone MM drivers
-  Hob = CreateHob (EFI_HOB_TYPE_RESOURCE_DESCRIPTOR, sizeof (EFI_HOB_RESOURCE_DESCRIPTOR));
+  //
-  ASSERT (Hob != NULL);
+  ASSERT (FALSE);
-
-  Hob->ResourceType      = ResourceType;
-  Hob->ResourceAttribute = ResourceAttribute;
-  Hob->PhysicalStart     = PhysicalStart;
-  Hob->ResourceLength    = NumberOfBytes;
 }
 
 /**
@@ -371,6 +317,9 @@ BuildResourceDescriptorHob (
   This function builds a customized HOB tagged with a GUID for identification
   and returns the start address of GUID HOB data so that caller can fill the customized data.
   The HOB Header and Name field is already stripped.
+  It can only be invoked by Standalone MM Core.
+  For Standalone MM drivers, it will ASSERT() since HOB is read only for Standalone MM drivers.
+
   If Guid is NULL, then ASSERT().
   If there is no additional space for HOB creation, then ASSERT().
   If DataLength >= (0x10000 - sizeof (EFI_HOB_GUID_TYPE)), then ASSERT().
@@ -388,16 +337,11 @@ BuildGuidHob (
   IN UINTN           DataLength
   )
 {
-  EFI_HOB_GUID_TYPE  *Hob;
-
   //
-  // Make sure that data length is not too long.
+  // HOB is read only for Standalone MM drivers
   //
-  ASSERT (DataLength <= (0xffff - sizeof (EFI_HOB_GUID_TYPE)));
+  ASSERT (FALSE);
-
+  return NULL;
-  Hob = CreateHob (EFI_HOB_TYPE_GUID_EXTENSION, (UINT16)(sizeof (EFI_HOB_GUID_TYPE) + DataLength));
-  CopyGuid (&Hob->Name, Guid);
-  return Hob + 1;
 }
 
 /**
@@ -406,6 +350,9 @@ BuildGuidHob (
   This function builds a customized HOB tagged with a GUID for identification,
   copies the input data to the HOB data field and returns the start address of the GUID HOB data.
   The HOB Header and Name field is already stripped.
+  It can only be invoked by Standalone MM Core.
+  For Standalone MM drivers, it will ASSERT() since HOB is read only for Standalone MM drivers.
+
   If Guid is NULL, then ASSERT().
   If Data is NULL and DataLength > 0, then ASSERT().
   If there is no additional space for HOB creation, then ASSERT().
@@ -426,19 +373,20 @@ BuildGuidDataHob (
   IN UINTN           DataLength
   )
 {
-  VOID  *HobData;
+  //
-
+  // HOB is read only for Standalone MM drivers
-  ASSERT (Data != NULL || DataLength == 0);
+  //
-
+  ASSERT (FALSE);
-  HobData = BuildGuidHob (Guid, DataLength);
+  return NULL;
-
-  return CopyMem (HobData, Data, DataLength);
 }
 
 /**
   Builds a Firmware Volume HOB.
 
   This function builds a Firmware Volume HOB.
+  It can only be invoked by Standalone MM Core.
+  For Standalone MM drivers, it will ASSERT() since HOB is read only for Standalone MM drivers.
+
   If there is no additional space for HOB creation, then ASSERT().
 
   @param  BaseAddress   The base address of the Firmware Volume.
@@ -452,18 +400,19 @@ BuildFvHob (
   IN UINT64                Length
   )
 {
-  EFI_HOB_FIRMWARE_VOLUME  *Hob;
+  //
-
+  // HOB is read only for Standalone MM drivers
-  Hob = CreateHob (EFI_HOB_TYPE_FV, sizeof (EFI_HOB_FIRMWARE_VOLUME));
+  //
-
+  ASSERT (FALSE);
-  Hob->BaseAddress = BaseAddress;
-  Hob->Length      = Length;
 }
 
 /**
   Builds a EFI_HOB_TYPE_FV2 HOB.
 
   This function builds a EFI_HOB_TYPE_FV2 HOB.
+  It can only be invoked by Standalone MM Core.
+  For Standalone MM drivers, it will ASSERT() since HOB is read only for Standalone MM drivers.
+
   If there is no additional space for HOB creation, then ASSERT().
 
   @param  BaseAddress   The base address of the Firmware Volume.
@@ -481,20 +430,19 @@ BuildFv2Hob (
   IN CONST    EFI_GUID              *FileName
   )
 {
-  EFI_HOB_FIRMWARE_VOLUME2  *Hob;
+  //
-
+  // HOB is read only for Standalone MM drivers
-  Hob = CreateHob (EFI_HOB_TYPE_FV2, sizeof (EFI_HOB_FIRMWARE_VOLUME2));
+  //
-
+  ASSERT (FALSE);
-  Hob->BaseAddress = BaseAddress;
-  Hob->Length      = Length;
-  CopyGuid (&Hob->FvName, FvName);
-  CopyGuid (&Hob->FileName, FileName);
 }
 
 /**
   Builds a HOB for the CPU.
 
   This function builds a HOB for the CPU.
+  It can only be invoked by Standalone MM Core.
+  For Standalone MM drivers, it will ASSERT() since HOB is read only for Standalone MM drivers.
+
   If there is no additional space for HOB creation, then ASSERT().
 
   @param  SizeOfMemorySpace   The maximum physical memory addressability of the processor.
@@ -508,23 +456,19 @@ BuildCpuHob (
   IN UINT8  SizeOfIoSpace
   )
 {
-  EFI_HOB_CPU  *Hob;
-
-  Hob = CreateHob (EFI_HOB_TYPE_CPU, sizeof (EFI_HOB_CPU));
-
-  Hob->SizeOfMemorySpace = SizeOfMemorySpace;
-  Hob->SizeOfIoSpace     = SizeOfIoSpace;
-
   //
-  // Zero the reserved space to match HOB spec
+  // HOB is read only for Standalone MM drivers
   //
-  ZeroMem (Hob->Reserved, sizeof (Hob->Reserved));
+  ASSERT (FALSE);
 }
 
 /**
   Builds a HOB for the memory allocation.
 
   This function builds a HOB for the memory allocation.
+  It can only be invoked by Standalone MM Core.
+  For Standalone MM drivers, it will ASSERT() since HOB is read only for Standalone MM drivers.
+
   If there is no additional space for HOB creation, then ASSERT().
 
   @param  BaseAddress   The 64 bit physical address of the memory.
@@ -540,23 +484,10 @@ BuildMemoryAllocationHob (
   IN EFI_MEMORY_TYPE       MemoryType
   )
 {
-  EFI_HOB_MEMORY_ALLOCATION  *Hob;
-
-  ASSERT (
-    ((BaseAddress & (EFI_PAGE_SIZE - 1)) == 0) &&
-    ((Length & (EFI_PAGE_SIZE - 1)) == 0)
-    );
-
-  Hob = CreateHob (EFI_HOB_TYPE_MEMORY_ALLOCATION, sizeof (EFI_HOB_MEMORY_ALLOCATION));
-
-  ZeroMem (&(Hob->AllocDescriptor.Name), sizeof (EFI_GUID));
-  Hob->AllocDescriptor.MemoryBaseAddress = BaseAddress;
-  Hob->AllocDescriptor.MemoryLength      = Length;
-  Hob->AllocDescriptor.MemoryType        = MemoryType;
   //
-  // Zero the reserved space to match HOB spec
+  // HOB is read only for Standalone MM drivers
   //
-  ZeroMem (Hob->AllocDescriptor.Reserved, sizeof (Hob->AllocDescriptor.Reserved));
+  ASSERT (FALSE);
 }
 
 /**