OvmfPkg/Sec/Ia32/SwitchStack.c

   1 /** @file
   2   Switch Stack functions.
   3
   4   Copyright (c) 2006 - 2007, 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 //
  16 // Include common header file for this module.
  17 //
  18
  19
  20 #include <Library/BaseLib.h>
  21 #include <Library/BaseMemoryLib.h>
  22 #include <Library/DebugLib.h>
  23 #include <Library/PeiServicesLib.h>
  24
  25 /**
  26   Transfers control to a function starting with a new stack.
  27
  28   Transfers control to the function specified by EntryPoint using the new stack
  29   specified by NewStack and passing in the parameters specified by Context1 and
  30   Context2. Context1 and Context2 are optional and may be NULL. The function
  31   EntryPoint must never return.
  32
  33   If EntryPoint is NULL, then ASSERT().
  34   If NewStack is NULL, then ASSERT().
  35
  36   @param  EntryPoint  A pointer to function to call with the new stack.
  37   @param  Context1    A pointer to the context to pass into the EntryPoint
  38                       function.
  39   @param  Context2    A pointer to the context to pass into the EntryPoint
  40                       function.
  41   @param  NewStack    A pointer to the new stack to use for the EntryPoint
  42                       function.
  43   @param  NewBsp      A pointer to the new BSP for the EntryPoint on IPF. It's
  44                       Reserved on other architectures.
  45
  46 **/
  47 VOID
  48 EFIAPI
  49 PeiSwitchStacks (
  50   IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,
  51   IN      VOID                      *Context1,  OPTIONAL
  52   IN      VOID                      *Context2,  OPTIONAL
  53   IN      VOID                      *Context3,  OPTIONAL
  54   IN      VOID                      *OldTopOfStack,
  55   IN      VOID                      *NewStack
  56   )
  57 {
  58   BASE_LIBRARY_JUMP_BUFFER  JumpBuffer;
  59
  60   ASSERT (EntryPoint != NULL);
  61   ASSERT (NewStack != NULL);
  62
  63   //
  64   // Stack should be aligned with CPU_STACK_ALIGNMENT
  65   //
  66   ASSERT (((UINTN)NewStack & (CPU_STACK_ALIGNMENT - 1)) == 0);
  67
  68   JumpBuffer.Eip = (UINTN)EntryPoint;
  69   JumpBuffer.Esp = (UINTN)NewStack - sizeof (VOID*);
  70   JumpBuffer.Esp -= sizeof (Context1) + sizeof (Context2) + sizeof(Context3);
  71   ((VOID**)JumpBuffer.Esp)[1] = Context1;
  72   ((VOID**)JumpBuffer.Esp)[2] = Context2;
  73   ((VOID**)JumpBuffer.Esp)[3] = Context3;
  74
  75   LongJump (&JumpBuffer, (UINTN)-1);
  76
  77   //
  78   // InternalSwitchStack () will never return
  79   //
  80   ASSERT (FALSE);
  81 }
  82
  83 /**
  84   Transfers control to a function starting with a new stack.
  85
  86   Transfers control to the function specified by EntryPoint using the new stack
  87   specified by NewStack and passing in the parameters specified by Context1 and
  88   Context2. Context1 and Context2 are optional and may be NULL. The function
  89   EntryPoint must never return.
  90
  91   If EntryPoint is NULL, then ASSERT().
  92   If NewStack is NULL, then ASSERT().
  93
  94   @param  EntryPoint  A pointer to function to call with the new stack.
  95   @param  Context1    A pointer to the context to pass into the EntryPoint
  96                       function.
  97   @param  Context2    A pointer to the context to pass into the EntryPoint
  98                       function.
  99   @param  NewStack    A pointer to the new stack to use for the EntryPoint
 100                       function.
 101   @param  NewBsp      A pointer to the new BSP for the EntryPoint on IPF. It's
 102                       Reserved on other architectures.
 103
 104 **/
 105 VOID
 106 EFIAPI
 107 SecSwitchStack (
 108   IN UINTN   TemporaryMemoryBase,
 109   IN UINTN   PermanentMemoryBase,
 110   IN UINTN   CopySize
 111   )
 112 {
 113   BASE_LIBRARY_JUMP_BUFFER  JumpBuffer;
 114   UINTN                     SetJumpFlag;
 115
 116   ASSERT ((VOID*)TemporaryMemoryBase != NULL);
 117   ASSERT ((VOID*)PermanentMemoryBase != NULL);
 118
 119   SetJumpFlag = SetJump (&JumpBuffer);
 120   //
 121   // The initial call to SetJump() must always return 0.
 122   // Subsequent calls to LongJump() may cause a non-zero value to be returned by SetJump().
 123   //
 124   if (SetJumpFlag == 0) {
 125     DEBUG ((EFI_D_ERROR, "SecSwitchStack+%d: Esp: 0x%xL\n", __LINE__, JumpBuffer.Esp));
 126     JumpBuffer.Esp =
 127       (INTN)JumpBuffer.Esp -
 128       (INTN)TemporaryMemoryBase +
 129       (INTN)PermanentMemoryBase;
 130     MemoryFence ();
 131     CopyMem((VOID*)PermanentMemoryBase, (VOID*)TemporaryMemoryBase, CopySize);
 132     LongJump (&JumpBuffer, (UINTN)-1);
 133   }
 134
 135 }
 136