MdePkg/Library/BaseLib/SwitchStack.c

   1 /** @file
   2   Switch Stack functions.
   3
   4   Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "BaseLibInternals.h"
  16
  17 /**
  18   Transfers control to a function starting with a new stack.
  19
  20   Transfers control to the function specified by EntryPoint using the
  21   new stack specified by NewStack and passing in the parameters specified
  22   by Context1 and Context2.  Context1 and Context2 are optional and may
  23   be NULL.  The function EntryPoint must never return.  This function
  24   supports a variable number of arguments following the NewStack parameter.
  25   These additional arguments are ignored on IA-32, x64, and EBC.
  26   IPF CPUs expect one additional parameter of type VOID * that specifies
  27   the new backing store pointer.
  28
  29   If EntryPoint is NULL, then ASSERT().
  30   If NewStack is NULL, then ASSERT().
  31
  32   @param  EntryPoint  A pointer to function to call with the new stack.
  33   @param  Context1    A pointer to the context to pass into the EntryPoint
  34                       function.
  35   @param  Context2    A pointer to the context to pass into the EntryPoint
  36                       function.
  37   @param  NewStack    A pointer to the new stack to use for the EntryPoint
  38                       function.
  39   @param  ...         This variable argument list is ignored for IA32, x64, and EBC.
  40                       For IPF, this variable argument list is expected to contain
  41                       a single parameter of type VOID * that specifies the new backing
  42                       store pointer.
  43
  44
  45 **/
  46 VOID
  47 EFIAPI
  48 SwitchStack (
  49   IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
  50   IN      VOID                      *Context1,  OPTIONAL
  51   IN      VOID                      *Context2,  OPTIONAL
  52   IN      VOID                      *NewStack,
  53   ...
  54   )
  55 {
  56   VA_LIST    Marker;
  57
  58   ASSERT (EntryPoint != NULL);
  59   ASSERT (NewStack != NULL);
  60
  61   //
  62   // New stack must be aligned with CPU_STACK_ALIGNMENT
  63   //
  64   ASSERT (((UINTN)NewStack & (CPU_STACK_ALIGNMENT - 1)) == 0);
  65
  66   VA_START (Marker, NewStack);
  67
  68   InternalSwitchStack (EntryPoint, Context1, Context2, NewStack, Marker);
  69
  70   VA_END (Marker);
  71
  72   //
  73   // InternalSwitchStack () will never return
  74   //
  75   ASSERT (FALSE);
  76 }