diff options
Diffstat (limited to 'EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/x86EnablePaging32.c')
-rw-r--r-- | EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/x86EnablePaging32.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/x86EnablePaging32.c b/EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/x86EnablePaging32.c new file mode 100644 index 0000000..44b0ee4 --- /dev/null +++ b/EDK/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); +} |