[PATCH v2 1/6] MdePkg/Base: introduce MAX_ALLOC_ADDRESS

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On some architectures, the maximum representable address deviates from
the virtual address range that is accessible by the firmware at boot
time. For instance, on AArch64, UEFI mandates a 4 KB page size, which
limits the address space to 48 bits, while more than that may be
populated on a particular platform, for use by the OS.

So introduce a new macro MAX_ALLOC_ADDRESS, which represent the maximum
address the firmware should take into account when allocating memory
ranges that need to be accessible by the CPU at boot time.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 MdePkg/Include/AArch64/ProcessorBind.h | 5 +++++
 MdePkg/Include/Arm/ProcessorBind.h     | 5 +++++
 MdePkg/Include/Ebc/ProcessorBind.h     | 5 +++++
 MdePkg/Include/Ia32/ProcessorBind.h    | 5 +++++
 MdePkg/Include/X64/ProcessorBind.h     | 5 +++++
 5 files changed, 25 insertions(+)

diff --git a/MdePkg/Include/AArch64/ProcessorBind.h b/MdePkg/Include/AArch64/ProcessorBind.h
index 968c18f915ae..f4a544b34d78 100644
--- a/MdePkg/Include/AArch64/ProcessorBind.h
+++ b/MdePkg/Include/AArch64/ProcessorBind.h
@@ -142,6 +142,11 @@ typedef INT64   INTN;
 ///
 #define MAX_ADDRESS   0xFFFFFFFFFFFFFFFFULL
 
+///
+/// Maximum usable address at boot time (48 bits using 4 KB pages)
+///
+#define MAX_ALLOC_ADDRESS   0xFFFFFFFFFFFFULL
+
 ///
 /// Maximum legal AArch64 INTN and UINTN values.
 ///
diff --git a/MdePkg/Include/Arm/ProcessorBind.h b/MdePkg/Include/Arm/ProcessorBind.h
index 8cca0f3bb050..16a61fc7a325 100644
--- a/MdePkg/Include/Arm/ProcessorBind.h
+++ b/MdePkg/Include/Arm/ProcessorBind.h
@@ -148,6 +148,11 @@ typedef INT32   INTN;
 ///
 #define MAX_ADDRESS  0xFFFFFFFF
 
+///
+/// Maximum usable address at boot time
+///
+#define MAX_ALLOC_ADDRESS   MAX_ADDRESS
+
 ///
 /// Maximum legal ARM INTN and UINTN values.
 ///
diff --git a/MdePkg/Include/Ebc/ProcessorBind.h b/MdePkg/Include/Ebc/ProcessorBind.h
index 5217cfd97eac..45beb7572817 100644
--- a/MdePkg/Include/Ebc/ProcessorBind.h
+++ b/MdePkg/Include/Ebc/ProcessorBind.h
@@ -103,6 +103,11 @@ typedef unsigned long         UINTN;
 ///
 #define MAX_ADDRESS   ((UINTN)(~0ULL >> (64 - sizeof (INTN) * 8)))
 
+///
+/// Maximum usable address at boot time (48 bits using 4 KB pages)
+///
+#define MAX_ALLOC_ADDRESS   MAX_ADDRESS
+
 ///
 /// Maximum legal EBC INTN and UINTN values.
 ///
diff --git a/MdePkg/Include/Ia32/ProcessorBind.h b/MdePkg/Include/Ia32/ProcessorBind.h
index 8e4de7029cfc..71d53e2543bb 100644
--- a/MdePkg/Include/Ia32/ProcessorBind.h
+++ b/MdePkg/Include/Ia32/ProcessorBind.h
@@ -246,6 +246,11 @@ typedef INT32   INTN;
 ///
 #define MAX_ADDRESS   0xFFFFFFFF
 
+///
+/// Maximum usable address at boot time
+///
+#define MAX_ALLOC_ADDRESS   MAX_ADDRESS
+
 ///
 /// Maximum legal IA-32 INTN and UINTN values.
 ///
diff --git a/MdePkg/Include/X64/ProcessorBind.h b/MdePkg/Include/X64/ProcessorBind.h
index e4254285877b..1c04090c7d03 100644
--- a/MdePkg/Include/X64/ProcessorBind.h
+++ b/MdePkg/Include/X64/ProcessorBind.h
@@ -260,6 +260,11 @@ typedef INT64   INTN;
 ///
 #define MAX_ADDRESS   0xFFFFFFFFFFFFFFFFULL
 
+///
+/// Maximum usable address at boot time
+///
+#define MAX_ALLOC_ADDRESS   MAX_ADDRESS
+
 ///
 /// Maximum legal x64 INTN and UINTN values.
 ///
-- 
2.19.2