1 files changed, 76 insertions, 0 deletions
diff --git a/UnixPkg/Library/UnixBaseLib/SwitchStack.c b/UnixPkg/Library/UnixBaseLib/SwitchStack.c
new file mode 100644
index 0000000000..36811175af
--- /dev/null
+++ b/UnixPkg/Library/UnixBaseLib/SwitchStack.c
@@ -0,0 +1,76 @@
+/** @file
+  Switch Stack functions.
+
+  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
+  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 "BaseLibInternals.h"
+
+/**
+  Transfers control to a function starting with a new stack.
+
+  Transfers control to the function specified by EntryPoint using the
+  new stack specified by NewStack and passing in the parameters specified
+  by Context1 and Context2.  Context1 and Context2 are optional and may
+  be NULL.  The function EntryPoint must never return.  This function
+  supports a variable number of arguments following the NewStack parameter.
+  These additional arguments are ignored on IA-32, x64, and EBC.
+  IPF CPUs expect one additional parameter of type VOID * that specifies
+  the new backing store pointer.
+
+  If EntryPoint is NULL, then ASSERT().
+  If NewStack is NULL, then ASSERT().
+
+  @param  EntryPoint  A pointer to function to call with the new stack.
+  @param  Context1    A pointer to the context to pass into the EntryPoint
+                      function.
+  @param  Context2    A pointer to the context to pass into the EntryPoint
+                      function.
+  @param  NewStack    A pointer to the new stack to use for the EntryPoint
+                      function.
+  @param  ...         This variable argument list is ignored for IA32, x64, and EBC.  
+                      For IPF, this variable argument list is expected to contain 
+                      a single parameter of type VOID * that specifies the new backing 
+                      store pointer.
+
+
+**/
+VOID
+EFIAPI
+SwitchStack (
+  IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
+  IN      VOID                      *Context1,  OPTIONAL
+  IN      VOID                      *Context2,  OPTIONAL
+  IN      VOID                      *NewStack,
+  ...
+  )
+{
+  VA_LIST    Marker;
+
+  ASSERT (EntryPoint != NULL);
+  ASSERT (NewStack != NULL);
+
+  //
+  // New stack must be aligned with CPU_STACK_ALIGNMENT
+  //
+  ASSERT (((UINTN)NewStack & (CPU_STACK_ALIGNMENT - 1)) == 0);
+
+  VA_START (Marker, NewStack);
+
+  InternalSwitchStack (EntryPoint, Context1, Context2, NewStack, Marker);
+
+  VA_END (Marker);
+
+  //
+  // InternalSwitchStack () will never return
+  //
+  ASSERT (FALSE);
+}