Moved the MdePkg to OldMdePkg so that new code in MdePkg does not break existing...

[mirror_edk2.git] / OldMdePkg / Library / BaseLib / x86DisablePaging32.c

diff --git a/OldMdePkg/Library/BaseLib/x86DisablePaging32.c b/OldMdePkg/Library/BaseLib/x86DisablePaging32.c
new file mode 100644 (file)
index 0000000..417a779
--- /dev/null
+++ b/OldMdePkg/Library/BaseLib/x86DisablePaging32.c
@@ -0,0 +1,65 @@
+/** @file\r
+  IA-32/x64 AsmDisablePaging32()\r
+\r
+  Copyright (c) 2006, Intel Corporation<BR>\r
+  All rights reserved. This program and the accompanying materials\r
+  are licensed and made available under the terms and conditions of the BSD License\r
+  which accompanies this distribution.  The full text of the license may be found at\r
+  http://opensource.org/licenses/bsd-license.php\r
+\r
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+\r
+  Module Name:  x86DisablePaging32.c\r
+\r
+**/\r
+\r
+#include "BaseLibInternals.h"\r
+\r
+/**\r
+  Disables the 32-bit paging mode on the CPU.\r
+\r
+  Disables the 32-bit paging mode on the CPU and returns to 32-bit protected\r
+  mode. This function assumes the current execution mode is 32-paged protected\r
+  mode. This function is only available on IA-32. After the 32-bit paging mode\r
+  is disabled, control is transferred to the function specified by EntryPoint\r
+  using the new stack specified by NewStack and passing in the parameters\r
+  specified by Context1 and Context2. Context1 and Context2 are optional and\r
+  may be NULL. The function EntryPoint must never return.\r
+\r
+  If the current execution mode is not 32-bit paged mode, then ASSERT().\r
+  If EntryPoint is NULL, then ASSERT().\r
+  If NewStack is NULL, then ASSERT().\r
+\r
+  There are a number of constraints that must be followed before calling this\r
+  function:\r
+  1)  Interrupts must be disabled.\r
+  2)  The caller must be in 32-bit paged mode.\r
+  3)  CR0, CR3, and CR4 must be compatible with 32-bit paged mode.\r
+  4)  CR3 must point to valid page tables that guarantee that the pages for\r
+      this function and the stack are identity mapped.\r
+\r
+  @param  EntryPoint  A pointer to function to call with the new stack after\r
+                      paging is disabled.\r
+  @param  Context1    A pointer to the context to pass into the EntryPoint\r
+                      function as the first parameter after paging is disabled.\r
+  @param  Context2    A pointer to the context to pass into the EntryPoint\r
+                      function as the second parameter after paging is\r
+                      disabled.\r
+  @param  NewStack    A pointer to the new stack to use for the EntryPoint\r
+                      function after paging is disabled.\r
+\r
+**/\r
+VOID\r
+EFIAPI\r
+AsmDisablePaging32 (\r
+  IN      SWITCH_STACK_ENTRY_POINT  EntryPoint,\r
+  IN      VOID                      *Context1,  OPTIONAL\r
+  IN      VOID                      *Context2,  OPTIONAL\r
+  IN      VOID                      *NewStack\r
+  )\r
+{\r
+  ASSERT (EntryPoint != NULL);\r
+  ASSERT (NewStack != NULL);\r
+  InternalX86DisablePaging32 (EntryPoint, Context1, Context2, NewStack);\r
+}\r