EmulatorPkg/Unix/Host/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 SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7
   8 --*/
   9
  10 #include "Host.h"
  11
  12
  13 /**
  14   Transfers control to a function starting with a new stack.
  15
  16   Transfers control to the function specified by EntryPoint using the new stack
  17   specified by NewStack and passing in the parameters specified by Context1 and
  18   Context2. Context1 and Context2 are optional and may be NULL. The function
  19   EntryPoint must never return.
  20
  21   If EntryPoint is NULL, then ASSERT().
  22   If NewStack is NULL, then ASSERT().
  23
  24   @param  EntryPoint  A pointer to function to call with the new stack.
  25   @param  Context1    A pointer to the context to pass into the EntryPoint
  26                       function.
  27   @param  Context2    A pointer to the context to pass into the EntryPoint
  28                       function.
  29   @param  NewStack    A pointer to the new stack to use for the EntryPoint
  30                       function.
  31
  32 **/
  33 VOID
  34 EFIAPI
  35 PeiSwitchStacks (
  36   IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
  37   IN      VOID                      *Context1   OPTIONAL,
  38   IN      VOID                      *Context2   OPTIONAL,
  39   IN      VOID                      *NewStack
  40   )
  41 {
  42   BASE_LIBRARY_JUMP_BUFFER  JumpBuffer;
  43
  44   ASSERT (EntryPoint != NULL);
  45   ASSERT (NewStack != NULL);
  46
  47   //
  48   // Stack should be aligned with CPU_STACK_ALIGNMENT
  49   //
  50   ASSERT (((UINTN)NewStack & (CPU_STACK_ALIGNMENT - 1)) == 0);
  51
  52   JumpBuffer.Eip = (UINTN)EntryPoint;
  53   JumpBuffer.Esp = (UINTN)NewStack - sizeof (VOID*);
  54   JumpBuffer.Esp -= sizeof (Context1) + sizeof (Context2);
  55   ((VOID**)JumpBuffer.Esp)[1] = Context1;
  56   ((VOID**)JumpBuffer.Esp)[2] = Context2;
  57
  58   LongJump (&JumpBuffer, (UINTN)-1);
  59
  60
  61   //
  62   // PeiSwitchStacks () will never return
  63   //
  64   ASSERT (FALSE);
  65 }