EmbeddedPkg: Add option to disable EFI Memory Attribute Protocol

Introduce a driver that allows users to disable the EFI Memory Attribute
protocol through an HII setup option, in order to work around a broken
version of rhboot's shim used in some distros (e.g. CentOS Stream 9)
which incorrectly invokes the protocol and results in a Synchronous
Exception.

Default is enabled, which can also be overridden at build time by
changing `gEmbeddedTokenSpaceGuid.PcdMemoryAttributeEnabledDefault`.

It is only applicable to ARM64 and there isn't any other technical
reason for disabling this security feature.

See:
- https://github.com/microsoft/mu_silicon_arm_tiano/issues/124
- https://edk2.groups.io/g/devel/topic/99631663
- https://github.com/tianocore/edk2/pull/5840

Signed-off-by: Mario Bălănică <mariobalanica02@gmail.com>

EmbeddedPkg/Drivers/MemoryAttributeManagerDxe/MemoryAttributeManagerDxe.c

@@ -0,0 +1,197 @@
+/** @file
+
+  Copyright (c) 2023-2024, Mario Bălănică <mariobalanica02@gmail.com>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi.h>
+#include <Library/DebugLib.h>
+#include <Library/DevicePathLib.h>
+#include <Library/HiiLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiRuntimeServicesTableLib.h>
+
+#include "MemoryAttributeManagerDxe.h"
+
+extern UINT8  MemoryAttributeManagerDxeHiiBin[];
+extern UINT8  MemoryAttributeManagerDxeStrings[];
+
+typedef struct {
+  VENDOR_DEVICE_PATH          VendorDevicePath;
+  EFI_DEVICE_PATH_PROTOCOL    End;
+} HII_VENDOR_DEVICE_PATH;
+
+STATIC HII_VENDOR_DEVICE_PATH  mVendorDevicePath = {
+  {
+    {
+      HARDWARE_DEVICE_PATH,
+      HW_VENDOR_DP,
+      {
+        (UINT8)(sizeof (VENDOR_DEVICE_PATH)),
+        (UINT8)((sizeof (VENDOR_DEVICE_PATH)) >> 8)
+      }
+    },
+    MEMORY_ATTRIBUTE_MANAGER_FORMSET_GUID
+  },
+  {
+    END_DEVICE_PATH_TYPE,
+    END_ENTIRE_DEVICE_PATH_SUBTYPE,
+    {
+      (UINT8)(END_DEVICE_PATH_LENGTH),
+      (UINT8)((END_DEVICE_PATH_LENGTH) >> 8)
+    }
+  }
+};
+
+/**
+  Installs HII page for user configuration.
+
+  @retval EFI_SUCCESS        The operation completed successfully.
+
+**/
+STATIC
+EFI_STATUS
+EFIAPI
+InstallHiiPages (
+  VOID
+  )
+{
+  EFI_STATUS      Status;
+  EFI_HII_HANDLE  HiiHandle;
+  EFI_HANDLE      DriverHandle;
+
+  DriverHandle = NULL;
+  Status       = gBS->InstallMultipleProtocolInterfaces (
+                        &DriverHandle,
+                        &gEfiDevicePathProtocolGuid,
+                        &mVendorDevicePath,
+                        NULL
+                        );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  HiiHandle = HiiAddPackages (
+                &gMemoryAttributeManagerFormSetGuid,
+                DriverHandle,
+                MemoryAttributeManagerDxeStrings,
+                MemoryAttributeManagerDxeHiiBin,
+                NULL
+                );
+
+  if (HiiHandle == NULL) {
+    gBS->UninstallMultipleProtocolInterfaces (
+           DriverHandle,
+           &gEfiDevicePathProtocolGuid,
+           &mVendorDevicePath,
+           NULL
+           );
+    return EFI_OUT_OF_RESOURCES;
+  }
+
+  return EFI_SUCCESS;
+}
+
+/**
+  This function uninstalls the EFI_MEMORY_ATTRIBUTE_PROTOCOL
+  from CpuDxe's handle.
+**/
+STATIC
+VOID
+UninstallEfiMemoryAttributeProtocol (
+  VOID
+  )
+{
+  EFI_STATUS  Status;
+  EFI_HANDLE  Handle;
+  UINTN       Size;
+  VOID        *MemoryAttributeProtocol;
+
+  Size   = sizeof (Handle);
+  Status = gBS->LocateHandle (
+                  ByProtocol,
+                  &gEfiMemoryAttributeProtocolGuid,
+                  NULL,
+                  &Size,
+                  &Handle
+                  );
+  if (EFI_ERROR (Status)) {
+    ASSERT (Status == EFI_NOT_FOUND);
+    return;
+  }
+
+  Status = gBS->HandleProtocol (
+                  Handle,
+                  &gEfiMemoryAttributeProtocolGuid,
+                  &MemoryAttributeProtocol
+                  );
+  ASSERT_EFI_ERROR (Status);
+  if (EFI_ERROR (Status)) {
+    return;
+  }
+
+  Status = gBS->UninstallProtocolInterface (
+                  Handle,
+                  &gEfiMemoryAttributeProtocolGuid,
+                  MemoryAttributeProtocol
+                  );
+  ASSERT_EFI_ERROR (Status);
+  if (EFI_ERROR (Status)) {
+    return;
+  }
+
+  DEBUG ((
+    DEBUG_INFO,
+    "EFI Memory Attribute Protocol disabled due to user/platform preference!\n"
+    ));
+}
+
+/**
+  The entry point for MemoryAttributeManagerDxe driver.
+
+  @param[in] ImageHandle     The image handle of the driver.
+  @param[in] SystemTable     The system table.
+
+  @retval EFI_SUCCESS        The operation completed successfully.
+
+**/
+EFI_STATUS
+EFIAPI
+MemoryAttributeManagerInitialize (
+  IN  EFI_HANDLE        ImageHandle,
+  IN  EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  EFI_STATUS                              Status;
+  UINTN                                   Size;
+  MEMORY_ATTRIBUTE_MANAGER_VARSTORE_DATA  Config;
+
+  Config.Enabled = PROTOCOL_ENABLED_DEFAULT;
+
+  Size   = sizeof (MEMORY_ATTRIBUTE_MANAGER_VARSTORE_DATA);
+  Status = gRT->GetVariable (
+                  MEMORY_ATTRIBUTE_MANAGER_DATA_VAR_NAME,
+                  &gMemoryAttributeManagerFormSetGuid,
+                  NULL,
+                  &Size,
+                  &Config
+                  );
+  if (EFI_ERROR (Status)) {
+    Status = gRT->SetVariable (
+                    MEMORY_ATTRIBUTE_MANAGER_DATA_VAR_NAME,
+                    &gMemoryAttributeManagerFormSetGuid,
+                    EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS,
+                    Size,
+                    &Config
+                    );
+    ASSERT_EFI_ERROR (Status);
+  }
+
+  if (!Config.Enabled) {
+    UninstallEfiMemoryAttributeProtocol ();
+  }
+
+  return InstallHiiPages ();
+}

EmbeddedPkg/Drivers/MemoryAttributeManagerDxe/MemoryAttributeManagerDxe.h

@@ -0,0 +1,22 @@
+/** @file
+
+  Copyright (c) 2023-2024, Mario Bălănică <mariobalanica02@gmail.com>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef MEMORY_ATTRIBUTE_MANAGER_DXE_H_
+#define MEMORY_ATTRIBUTE_MANAGER_DXE_H_
+
+#include <Guid/MemoryAttributeManagerFormSet.h>
+
+#define PROTOCOL_ENABLED_DEFAULT  FixedPcdGetBool(PcdMemoryAttributeEnabledDefault)
+
+#define MEMORY_ATTRIBUTE_MANAGER_DATA_VAR_NAME  L"MemoryAttributeManagerData"
+
+typedef struct {
+  BOOLEAN    Enabled;
+} MEMORY_ATTRIBUTE_MANAGER_VARSTORE_DATA;
+
+#endif // __MEMORY_ATTRIBUTE_MANAGER_DXE_H__

EmbeddedPkg/Drivers/MemoryAttributeManagerDxe/MemoryAttributeManagerDxe.inf

@@ -0,0 +1,62 @@
+## @file
+#  EFI Memory Attribute Protocol state manager
+#
+#  This driver allows users to disable the EFI Memory Attribute protocol
+#  through an HII setup option, in order to work around a broken version
+#  of rhboot's shim used in some distros (e.g. CentOS Stream 9) which
+#  incorrectly invokes the protocol and results in a Synchronous Exception.
+#
+#  It is only applicable to ARM64 and there isn't any other technical
+#  reason for disabling this security feature.
+#
+#  See:
+#    - https://github.com/microsoft/mu_silicon_arm_tiano/issues/124
+#    - https://edk2.groups.io/g/devel/topic/99631663
+#    - https://github.com/tianocore/edk2/pull/5840
+#
+#  Copyright (c) 2023-2024, Mario Bălănică <mariobalanica02@gmail.com>
+#
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001001B
+  BASE_NAME                      = MemoryAttributeManagerDxe
+  FILE_GUID                      = 5319346b-66ad-433a-9a91-f7fc286bc9a1
+  MODULE_TYPE                    = DXE_DRIVER
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = MemoryAttributeManagerInitialize
+
+[Sources]
+  MemoryAttributeManagerDxe.c
+  MemoryAttributeManagerDxe.h
+  MemoryAttributeManagerDxeHii.uni
+  MemoryAttributeManagerDxeHii.vfr
+
+[Packages]
+  EmbeddedPkg/EmbeddedPkg.dec
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+
+[LibraryClasses]
+  DebugLib
+  DevicePathLib
+  HiiLib
+  UefiBootServicesTableLib
+  UefiRuntimeServicesTableLib
+  UefiDriverEntryPoint
+
+[Guids]
+  gMemoryAttributeManagerFormSetGuid
+
+[Protocols]
+  gEfiMemoryAttributeProtocolGuid
+
+[Pcd]
+  gEmbeddedTokenSpaceGuid.PcdMemoryAttributeEnabledDefault
+
+[Depex]
+  gEfiVariableArchProtocolGuid        AND
+  gEfiVariableWriteArchProtocolGuid   AND
+  gEfiMemoryAttributeProtocolGuid

EmbeddedPkg/Drivers/MemoryAttributeManagerDxe/MemoryAttributeManagerDxeHii.uni

@@ -0,0 +1,17 @@
+/** @file
+
+  Copyright (c) 2023-2024, Mario Bălănică <mariobalanica02@gmail.com>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#langdef en-US  "English"
+
+#string STR_NULL_STRING                                    #language en-US ""
+
+#string STR_FORM_SET_TITLE                                 #language en-US "EFI Memory Attribute Protocol"
+#string STR_FORM_SET_TITLE_HELP                            #language en-US "Configure the state of the EFI Memory Attribute Protocol.\n\n"
+                                                                           "Some old OS loader versions (e.g. as found in CentOS Stream 9) do not properly support the protocol and may cause a Synchronous Exception. This security feature can be disabled to work around the issue; otherwise it should be kept enabled."
+
+#string STR_ENABLE_PROTOCOL_PROMPT                         #language en-US "Enable Protocol"

EmbeddedPkg/Drivers/MemoryAttributeManagerDxe/MemoryAttributeManagerDxeHii.vfr

@@ -0,0 +1,35 @@
+/** @file
+
+  Copyright (c) 2023-2024, Mario Bălănică <mariobalanica02@gmail.com>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi/UefiMultiPhase.h>
+#include <Guid/HiiPlatformSetupFormset.h>
+
+#include "MemoryAttributeManagerDxe.h"
+
+formset
+  guid      = MEMORY_ATTRIBUTE_MANAGER_FORMSET_GUID,
+  title     = STRING_TOKEN(STR_FORM_SET_TITLE),
+  help      = STRING_TOKEN(STR_FORM_SET_TITLE_HELP),
+  classguid = EFI_HII_PLATFORM_SETUP_FORMSET_GUID,
+
+  efivarstore MEMORY_ATTRIBUTE_MANAGER_VARSTORE_DATA,
+  attribute = EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_NON_VOLATILE,
+  name  = MemoryAttributeManagerData,
+  guid  = MEMORY_ATTRIBUTE_MANAGER_FORMSET_GUID;
+
+  form formid = 1,
+    title  = STRING_TOKEN(STR_FORM_SET_TITLE);
+
+    checkbox varid = MemoryAttributeManagerData.Enabled,
+      prompt      = STRING_TOKEN(STR_ENABLE_PROTOCOL_PROMPT),
+      help        = STRING_TOKEN(STR_NULL_STRING),
+      flags       = CHECKBOX_DEFAULT | CHECKBOX_DEFAULT_MFG | RESET_REQUIRED,
+      default     = PROTOCOL_ENABLED_DEFAULT,
+    endcheckbox;
+  endform;
+endformset;

EmbeddedPkg/EmbeddedPkg.dec

@@ -73,6 +73,9 @@
   ## Include/Guid/NvVarStoreFormatted.h
   gEdkiiNvVarStoreFormattedGuid = { 0xd1a86e3f, 0x0707, 0x4c35, { 0x83, 0xcd, 0xdc, 0x2c, 0x29, 0xc8, 0x91, 0xa3 } }
 
+  # Include/Guid/MemoryAttributeManagerFormSet.h
+  gMemoryAttributeManagerFormSetGuid = { 0xefab3427, 0x4793, 0x4e9e, { 0xaa, 0x29, 0x88, 0x0c, 0x9a, 0x77, 0x5b, 0x5f } }
+
 [Protocols.common]
   gHardwareInterruptProtocolGuid =  { 0x2890B3EA, 0x053D, 0x1643, { 0xAD, 0x0C, 0xD6, 0x48, 0x08, 0xDA, 0x3F, 0xF1 } }
   gHardwareInterrupt2ProtocolGuid = { 0x32898322, 0x2da1, 0x474a, { 0xba, 0xaa, 0xf3, 0xf7, 0xcf, 0x56, 0x94, 0x70 } }
@@ -192,3 +195,8 @@
   # Expected Overflow Android Kernel Command Line Characters
   #
   gEmbeddedTokenSpaceGuid.PcdAndroidKernelCommandLineOverflow|0|UINT32|0x000005C
+
+  #
+  # EFI Memory Attribute Protocol default enable state
+  #
+  gEmbeddedTokenSpaceGuid.PcdMemoryAttributeEnabledDefault|TRUE|BOOLEAN|0x00000060

EmbeddedPkg/EmbeddedPkg.dsc

@@ -239,6 +239,8 @@
   EmbeddedPkg/Drivers/DtPlatformDxe/DtPlatformDxe.inf
   EmbeddedPkg/Drivers/FdtClientDxe/FdtClientDxe.inf
 
+  EmbeddedPkg/Drivers/MemoryAttributeManagerDxe/MemoryAttributeManagerDxe.inf
+
   EmbeddedPkg/Drivers/NonCoherentIoMmuDxe/NonCoherentIoMmuDxe.inf {
     <LibraryClasses>
       DmaLib|EmbeddedPkg/Library/NonCoherentDmaLib/NonCoherentDmaLib.inf

EmbeddedPkg/Include/Guid/MemoryAttributeManagerFormSet.h

@@ -0,0 +1,17 @@
+/** @file
+
+  Copyright (c) 2023-2024, Mario Bălănică <mariobalanica02@gmail.com>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef MEMORY_ATTRIBUTE_MANAGER_FORMSET_H_
+#define MEMORY_ATTRIBUTE_MANAGER_FORMSET_H_
+
+#define MEMORY_ATTRIBUTE_MANAGER_FORMSET_GUID \
+  { 0xefab3427, 0x4793, 0x4e9e, { 0xaa, 0x29, 0x88, 0x0c, 0x9a, 0x77, 0x5b, 0x5f } }
+
+extern EFI_GUID  gMemoryAttributeManagerFormSetGuid;
+
+#endif // __MEMORY_ATTRIBUTE_MANAGER_FORMSET_H__