The Standalone MM environment runs in S-EL0 in AArch64 on ARM Standard
Platforms. Privileged firmware e.g. ARM Trusted Firmware sets up its
architectural context including the initial translation tables for the
S-EL1/EL0 translation regime. The MM environment could still request ARM
TF to change the memory attributes of memory regions during
initialization.

This patch adds a simple MMU library suitable for execution in S-EL0 and
requesting operations from higher exception levels.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Achin Gupta <achin.gu...@arm.com>
Signed-off-by: Supreeth Venkatesh <supreeth.venkat...@arm.com>
---
 ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuSecLib.c | 146 ++++++++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100644 ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuSecLib.c

diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuSecLib.c 
b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuSecLib.c
new file mode 100644
index 0000000000..56969e31d1
--- /dev/null
+++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuSecLib.c
@@ -0,0 +1,146 @@
+/** @file
+*  File managing the MMU for ARMv8 architecture in S-EL0
+*
+*  Copyright (c) 2017, ARM Limited. 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 <Uefi.h>
+#include <Chipset/AArch64.h>
+#include <IndustryStandard/ArmMmSvc.h>
+
+#include <Library/ArmLib.h>
+#include <Library/ArmMmuLib.h>
+#include <Library/ArmSvcLib.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+
+EFI_STATUS
+RequestMemoryPermissionChange(
+  IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
+  IN  UINT64                    Length,
+  IN  UINTN                     Permissions
+  )
+{
+  EFI_STATUS    Status;
+  ARM_SVC_ARGS  ChangeMemoryPermissionsSvcArgs = {0};
+
+  ChangeMemoryPermissionsSvcArgs.Arg0 = 
ARM_SVC_ID_SP_SET_MEM_ATTRIBUTES_AARCH64;
+  ChangeMemoryPermissionsSvcArgs.Arg1 = BaseAddress;
+  ChangeMemoryPermissionsSvcArgs.Arg2 = (Length >= EFI_PAGE_SIZE) ? \
+                                         Length >> EFI_PAGE_SHIFT : 1;
+  ChangeMemoryPermissionsSvcArgs.Arg3 = Permissions;
+
+  ArmCallSvc(&ChangeMemoryPermissionsSvcArgs);
+
+  Status = ChangeMemoryPermissionsSvcArgs.Arg0;
+
+  switch (Status) {
+  case ARM_SVC_SPM_RET_SUCCESS:
+    Status = EFI_SUCCESS;
+    break;
+
+  case ARM_SVC_SPM_RET_NOT_SUPPORTED:
+    Status = EFI_UNSUPPORTED;
+    break;
+
+  case ARM_SVC_SPM_RET_INVALID_PARAMS:
+    Status = EFI_INVALID_PARAMETER;
+    break;
+
+  case ARM_SVC_SPM_RET_DENIED:
+    Status = EFI_ACCESS_DENIED;
+    break;
+
+  case ARM_SVC_SPM_RET_NO_MEMORY:
+    Status = EFI_BAD_BUFFER_SIZE;
+    break;
+
+  default:
+    Status = EFI_ACCESS_DENIED;
+    ASSERT (0);
+  }
+
+  return Status;
+}
+
+EFI_STATUS
+ArmSetMemoryRegionNoExec (
+  IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
+  IN  UINT64                    Length
+  )
+{
+  return RequestMemoryPermissionChange(BaseAddress,
+                                       Length,
+                                       SET_MEM_ATTR_MAKE_PERM_REQUEST( \
+                                         SET_MEM_ATTR_DATA_PERM_RO, \
+                                         SET_MEM_ATTR_CODE_PERM_XN));
+}
+
+EFI_STATUS
+ArmClearMemoryRegionNoExec (
+  IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
+  IN  UINT64                    Length
+  )
+{
+  return RequestMemoryPermissionChange(BaseAddress,
+                                       Length,
+                                       SET_MEM_ATTR_MAKE_PERM_REQUEST( \
+                                         SET_MEM_ATTR_DATA_PERM_RO, \
+                                         SET_MEM_ATTR_CODE_PERM_X));
+}
+
+EFI_STATUS
+ArmSetMemoryRegionReadOnly (
+  IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
+  IN  UINT64                    Length
+  )
+{
+  return RequestMemoryPermissionChange(BaseAddress,
+                                       Length,
+                                       SET_MEM_ATTR_MAKE_PERM_REQUEST( \
+                                         SET_MEM_ATTR_DATA_PERM_RO, \
+                                         SET_MEM_ATTR_CODE_PERM_XN));
+}
+
+EFI_STATUS
+ArmClearMemoryRegionReadOnly (
+  IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
+  IN  UINT64                    Length
+  )
+{
+  return RequestMemoryPermissionChange(BaseAddress,
+                                       Length,
+                                       SET_MEM_ATTR_MAKE_PERM_REQUEST( \
+                                         SET_MEM_ATTR_DATA_PERM_RW, \
+                                         SET_MEM_ATTR_CODE_PERM_XN));
+}
+
+EFI_STATUS
+EFIAPI
+ArmConfigureMmu (
+  IN  ARM_MEMORY_REGION_DESCRIPTOR  *MemoryTable,
+  OUT VOID                          **TranslationTableBase OPTIONAL,
+  OUT UINTN                         *TranslationTableSize OPTIONAL
+  )
+{
+  return EFI_UNSUPPORTED;
+}
+
+EFI_STATUS
+EFIAPI
+ArmMmuSecLibConstructor (
+  IN EFI_HANDLE            ImageHandle,
+  IN EFI_MM_SYSTEM_TABLE   *MmSystemTable
+  )
+{
+  return EFI_SUCCESS;
+}
-- 
2.16.2

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