MdePkg: Replace BSD License with BSD+Patent License

[mirror_edk2.git] / MdePkg / Library / BaseLib / Ia32 / EnablePaging32.c

diff --git a/MdePkg/Library/BaseLib/Ia32/EnablePaging32.c b/MdePkg/Library/BaseLib/Ia32/EnablePaging32.c
index e4765a7f2864f17a9d0405edccff524a88a6d294..ce0c71067db19bf5f7b3331fffb19f2044056aab 100644 (file)
--- a/MdePkg/Library/BaseLib/Ia32/EnablePaging32.c
+++ b/MdePkg/Library/BaseLib/Ia32/EnablePaging32.c
@@ -1,22 +1,46 @@
 /** @file\r
   AsmEnablePaging32 function\r
 \r
-  Copyright (c) 2006 - 2007, 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
+  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>\r
+  SPDX-License-Identifier: BSD-2-Clause-Patent\r
 \r
 **/\r
 \r
-//\r
-// Include common header file for this module.\r
-//\r
-#include "CommonHeader.h"\r
+#include "BaseLibInternals.h"\r
+\r
+/**\r
+  Enables the 32-bit paging mode on the CPU.\r
+\r
+  Enables the 32-bit paging mode on the CPU. CR0, CR3, CR4, and the page tables\r
+  must be properly initialized prior to calling this service. This function\r
+  assumes the current execution mode is 32-bit protected mode. This function is\r
+  only available on IA-32. After the 32-bit paging mode is enabled, control is\r
+  transferred to the function specified by EntryPoint using the new stack\r
+  specified by NewStack and passing in the parameters specified by Context1 and\r
+  Context2. Context1 and Context2 are optional and may be NULL. The function\r
+  EntryPoint must never return.\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 protected mode with flat descriptors. This\r
+      means all descriptors must have a base of 0 and a limit of 4GB.\r
+  3)  CR0 and CR4 must be compatible with 32-bit protected mode with flat\r
+      descriptors.\r
+  4)  CR3 must point to valid page tables that will be used once the transition\r
+      is complete, and those page tables must guarantee that the pages for this\r
+      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 enabled.\r
+  @param  Context1    A pointer to the context to pass into the EntryPoint\r
+                      function as the first parameter after paging is enabled.\r
+  @param  Context2    A pointer to the context to pass into the EntryPoint\r
+                      function as the second parameter after paging is enabled.\r
+  @param  NewStack    A pointer to the new stack to use for the EntryPoint\r
+                      function after paging is enabled.\r
+\r
+**/\r
 __declspec (naked)\r
 VOID\r
 EFIAPI\r