diff options
author | Guo Mang <mang.guo@intel.com> | 2016-12-22 15:57:14 +0800 |
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committer | Guo Mang <mang.guo@intel.com> | 2016-12-26 19:14:41 +0800 |
commit | 1760cf81e4b1847c6823ea3514a78dd120e19b6e (patch) | |
tree | 64a874b14050fe24d3bbc1bc13cd293abf8ae018 /Core/MdePkg/Library/BaseLib/Ia32/EnablePaging32.c | |
parent | 7f05fa00f73038b425002566d3afe6c3ade2ccdb (diff) | |
download | edk2-platforms-1760cf81e4b1847c6823ea3514a78dd120e19b6e.tar.xz |
MdePkg: Move to new location
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Guo Mang <mang.guo@intel.com>
Diffstat (limited to 'Core/MdePkg/Library/BaseLib/Ia32/EnablePaging32.c')
-rw-r--r-- | Core/MdePkg/Library/BaseLib/Ia32/EnablePaging32.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/Core/MdePkg/Library/BaseLib/Ia32/EnablePaging32.c b/Core/MdePkg/Library/BaseLib/Ia32/EnablePaging32.c new file mode 100644 index 0000000000..d0c2e9471f --- /dev/null +++ b/Core/MdePkg/Library/BaseLib/Ia32/EnablePaging32.c @@ -0,0 +1,81 @@ +/** @file
+ AsmEnablePaging32 function
+
+ Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
+ 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.
+
+**/
+
+#include "BaseLibInternals.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.
+
+ 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.
+
+**/
+__declspec (naked)
+VOID
+EFIAPI
+InternalX86EnablePaging32 (
+ IN SWITCH_STACK_ENTRY_POINT EntryPoint,
+ IN VOID *Context1, OPTIONAL
+ IN VOID *Context2, OPTIONAL
+ IN VOID *NewStack
+ )
+{
+ _asm {
+ push ebp
+ mov ebp, esp
+ mov ebx, EntryPoint
+ mov ecx, Context1
+ mov edx, Context2
+ pushfd
+ pop edi
+ cli
+ mov eax, cr0
+ bts eax, 31
+ mov esp, NewStack
+ mov cr0, eax
+ push edi
+ popfd
+ push edx
+ push ecx
+ call ebx
+ jmp $
+ }
+}
+
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