ArmPkg/ArmMmuLib ARM: split ArmMmuLibCore.c into core and update code

Unlike the AArch64 implementation of ArmMmuLib, which combines the
initial page table population code with the code that runs at later
stages to manage permission attributes in the page tables, ARM uses
two completely separate sets of routines for this.

Since ArmMmuLib is a static library, we can prevent duplication of
this code between different users, which usually only need one or
the other. (Note that LTO should also achieve the same.)

This also makes it easier to reason about modifying the cache
maintenance handling, and replace the set/way ops with by-VA
ops, since the code that performs the set/way ops only executes
when the MMU is still off.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>

ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibConvert.c

@@ -0,0 +1,32 @@
+/** @file
+*  File managing the MMU for ARMv7 architecture
+*
+*  Copyright (c) 2011-2016, ARM Limited. All rights reserved.
+*
+*  SPDX-License-Identifier: BSD-2-Clause-Patent
+*
+**/
+
+#include <Uefi.h>
+
+#include <Library/ArmLib.h>
+
+#include <Chipset/ArmV7.h>
+
+UINT32
+ConvertSectionAttributesToPageAttributes (
+  IN UINT32   SectionAttributes,
+  IN BOOLEAN  IsLargePage
+  )
+{
+  UINT32 PageAttributes;
+
+  PageAttributes = 0;
+  PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_CACHE_POLICY (SectionAttributes, IsLargePage);
+  PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_AP (SectionAttributes);
+  PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_XN (SectionAttributes, IsLargePage);
+  PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_NG (SectionAttributes);
+  PageAttributes |= TT_DESCRIPTOR_CONVERT_TO_PAGE_S (SectionAttributes);
+
+  return PageAttributes;
+}