1 files changed, 65 insertions, 0 deletions
diff --git a/roms/edk2/MdePkg/Library/BaseLib/AArch64/SwitchStack.S b/roms/edk2/MdePkg/Library/BaseLib/AArch64/SwitchStack.S
new file mode 100644
index 000000000..f3bce6a09
--- /dev/null
+++ b/roms/edk2/MdePkg/Library/BaseLib/AArch64/SwitchStack.S
@@ -0,0 +1,65 @@
+#------------------------------------------------------------------------------
+#
+# Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
+# Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
+# Portions copyright (c) 2011 - 2013, ARM Limited. All rights reserved.<BR>
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#------------------------------------------------------------------------------
+
+.text
+.align 5
+
+GCC_ASM_EXPORT(InternalSwitchStackAsm)
+GCC_ASM_EXPORT(CpuPause)
+
+#/**
+#
+#  This allows the caller to switch the stack and goes to the new entry point
+#
+# @param      EntryPoint   The pointer to the location to enter
+# @param      Context      Parameter to pass in
+# @param      Context2     Parameter2 to pass in
+# @param      NewStack     New Location of the stack
+#
+# @return     Nothing. Goes to the Entry Point passing in the new parameters
+#
+#**/
+#VOID
+#EFIAPI
+#InternalSwitchStackAsm (
+#  SWITCH_STACK_ENTRY_POINT EntryPoint,
+#  VOID  *Context,
+#  VOID  *Context2,
+#  VOID  *NewStack
+#  );
+#
+ASM_PFX(InternalSwitchStackAsm):
+    mov   x29, #0
+    mov   x30, x0
+    mov   sp, x3
+    mov   x0, x1
+    mov   x1, x2
+    ret
+
+#/**
+#
+#  Requests CPU to pause for a short period of time.
+#
+#  Requests CPU to pause for a short period of time. Typically used in MP
+#  systems to prevent memory starvation while waiting for a spin lock.
+#
+#**/
+#VOID
+#EFIAPI
+#CpuPause (
+#  VOID
+#  )
+#
+ASM_PFX(CpuPause):
+    nop
+    nop
+    nop
+    nop
+    nop
+    ret