diff options
Diffstat (limited to 'EdkCompatibilityPkg/Foundation/Library/EdkIIGlueLib/Library/BaseLib/x86EnablePaging32.c')
-rw-r--r-- | EdkCompatibilityPkg/Foundation/Library/EdkIIGlueLib/Library/BaseLib/x86EnablePaging32.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/EdkCompatibilityPkg/Foundation/Library/EdkIIGlueLib/Library/BaseLib/x86EnablePaging32.c b/EdkCompatibilityPkg/Foundation/Library/EdkIIGlueLib/Library/BaseLib/x86EnablePaging32.c new file mode 100644 index 0000000000..33622a5a44 --- /dev/null +++ b/EdkCompatibilityPkg/Foundation/Library/EdkIIGlueLib/Library/BaseLib/x86EnablePaging32.c @@ -0,0 +1,74 @@ +/*++
+
+Copyright (c) 2004 - 2006, Intel Corporation
+All rights reserved. This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution. The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+
+Module Name:
+
+ x86EnablePaging32.c
+
+Abstract:
+
+ IA-32/x64 specific functions.
+
+--*/
+
+#include "BaseLibInternal.h"
+
+/**
+ Enables the 32-bit paging mode on the CPU.
+
+ Enables the 32-bit paging mode on the CPU. CR0, CR3, CR4, and the page tables
+ must be properly initialized prior to calling this service. This function
+ assumes the current execution mode is 32-bit protected mode. This function is
+ only available on IA-32. After the 32-bit paging mode is enabled, control is
+ transferred to the function specified by EntryPoint using the new stack
+ specified by NewStack and passing in the parameters specified by Context1 and
+ Context2. Context1 and Context2 are optional and may be NULL. The function
+ EntryPoint must never return.
+
+ If the current execution mode is not 32-bit protected mode, then ASSERT().
+ If EntryPoint is NULL, then ASSERT().
+ If NewStack is NULL, then ASSERT().
+
+ There are a number of constraints that must be followed before calling this
+ function:
+ 1) Interrupts must be disabled.
+ 2) The caller must be in 32-bit protected mode with flat descriptors. This
+ means all descriptors must have a base of 0 and a limit of 4GB.
+ 3) CR0 and CR4 must be compatible with 32-bit protected mode with flat
+ descriptors.
+ 4) CR3 must point to valid page tables that will be used once the transition
+ is complete, and those page tables must guarantee that the pages for this
+ function and the stack are identity mapped.
+
+ @param EntryPoint A pointer to function to call with the new stack after
+ paging is enabled.
+ @param Context1 A pointer to the context to pass into the EntryPoint
+ function as the first parameter after paging is enabled.
+ @param Context2 A pointer to the context to pass into the EntryPoint
+ function as the second parameter after paging is enabled.
+ @param NewStack A pointer to the new stack to use for the EntryPoint
+ function after paging is enabled.
+
+**/
+VOID
+EFIAPI
+AsmEnablePaging32 (
+ IN SWITCH_STACK_ENTRY_POINT EntryPoint,
+ IN VOID *Context1, OPTIONAL
+ IN VOID *Context2, OPTIONAL
+ IN VOID *NewStack
+ )
+{
+ ASSERT (EntryPoint != NULL);
+ ASSERT (NewStack != NULL);
+ InternalX86EnablePaging32 (EntryPoint, Context1, Context2, NewStack);
+}
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