MdePkg/Library/BaseLib/Ia32/InternalSwitchStack.c

   1 /** @file
   2   SwitchStack() function for IA-32.
   3
   4   Copyright (c) 2006 - 2007, Intel Corporation<BR>
   5   All rights reserved. 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   Module Name:  InternalSwitchStack.c
  14
  15 **/
  16
  17 //
  18 // Include common header file for this module.
  19 //
  20 #include <BaseLibInternals.h>
  21
  22
  23 /**
  24   Transfers control to a function starting with a new stack.
  25
  26   Transfers control to the function specified by EntryPoint using the
  27   new stack specified by NewStack and passing in the parameters specified
  28   by Context1 and Context2.  Context1 and Context2 are optional and may
  29   be NULL.  The function EntryPoint must never return.
  30   Marker will be ignored on IA-32, x64, and EBC.
  31   IPF CPUs expect one additional parameter of type VOID * that specifies
  32   the new backing store pointer.
  33
  34   If EntryPoint is NULL, then ASSERT().
  35   If NewStack is NULL, then ASSERT().
  36
  37   @param  EntryPoint  A pointer to function to call with the new stack.
  38   @param  Context1    A pointer to the context to pass into the EntryPoint
  39                       function.
  40   @param  Context2    A pointer to the context to pass into the EntryPoint
  41                       function.
  42   @param  NewStack    A pointer to the new stack to use for the EntryPoint
  43                       function.
  44   @param  Marker      VA_LIST marker for the variable argument list.
  45
  46 **/
  47 VOID
  48 EFIAPI
  49 InternalSwitchStack (
  50   IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
  51   IN      VOID                      *Context1,   OPTIONAL
  52   IN      VOID                      *Context2,   OPTIONAL
  53   IN      VOID                      *NewStack,
  54   IN      VA_LIST                   Marker
  55   )
  56 {
  57   BASE_LIBRARY_JUMP_BUFFER  JumpBuffer;
  58
  59   //
  60   // Stack should be aligned with CPU_STACK_ALIGNMENT
  61   //
  62   ASSERT (((UINTN)NewStack & (CPU_STACK_ALIGNMENT - 1)) == 0);
  63
  64   JumpBuffer.Eip = (UINTN)EntryPoint;
  65   JumpBuffer.Esp = (UINTN)NewStack - sizeof (VOID*);
  66   JumpBuffer.Esp -= sizeof (Context1) + sizeof (Context2);
  67   ((VOID**)JumpBuffer.Esp)[1] = Context1;
  68   ((VOID**)JumpBuffer.Esp)[2] = Context2;
  69
  70   LongJump (&JumpBuffer, (UINTN)-1);
  71 }