InOsEmuPkg/Unix/Sec/Ia32/SwitchStack.c

   1 /*++
   2
   3 Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
   4 Portions copyright (c) 2008 - 2009, Apple Inc. 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
  16 #include "SecMain.h"
  17
  18
  19 /**
  20   Transfers control to a function starting with a new stack.
  21
  22   Transfers control to the function specified by EntryPoint using the new stack
  23   specified by NewStack and passing in the parameters specified by Context1 and
  24   Context2. Context1 and Context2 are optional and may be NULL. The function
  25   EntryPoint must never return.
  26
  27   If EntryPoint is NULL, then ASSERT().
  28   If NewStack is NULL, then ASSERT().
  29
  30   @param  EntryPoint  A pointer to function to call with the new stack.
  31   @param  Context1    A pointer to the context to pass into the EntryPoint
  32                       function.
  33   @param  Context2    A pointer to the context to pass into the EntryPoint
  34                       function.
  35   @param  NewStack    A pointer to the new stack to use for the EntryPoint
  36                       function.
  37
  38 **/
  39 VOID
  40 EFIAPI
  41 PeiSwitchStacks (
  42   IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
  43   IN      VOID                      *Context1,  OPTIONAL
  44   IN      VOID                      *Context2,  OPTIONAL
  45   IN      VOID                      *NewStack
  46   )
  47 {
  48   BASE_LIBRARY_JUMP_BUFFER  JumpBuffer;
  49
  50   ASSERT (EntryPoint != NULL);
  51   ASSERT (NewStack != NULL);
  52
  53   //
  54   // Stack should be aligned with CPU_STACK_ALIGNMENT
  55   //
  56   ASSERT (((UINTN)NewStack & (CPU_STACK_ALIGNMENT - 1)) == 0);
  57
  58   JumpBuffer.Eip = (UINTN)EntryPoint;
  59   JumpBuffer.Esp = (UINTN)NewStack - sizeof (VOID*);
  60   JumpBuffer.Esp -= sizeof (Context1) + sizeof (Context2);
  61   ((VOID**)JumpBuffer.Esp)[1] = Context1;
  62   ((VOID**)JumpBuffer.Esp)[2] = Context2;
  63
  64   LongJump (&JumpBuffer, (UINTN)-1);
  65
  66
  67   //
  68   // PeiSwitchStacks () will never return
  69   //
  70   ASSERT (FALSE);
  71 }
  72
  73
  74