1 /** @file
2 IA-32/x64 AsmDisablePaging32()
3
4 Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
5 SPDX-License-Identifier: BSD-2-Clause-Patent
6
7 **/
8
9
10
11
12 #include "BaseLibInternals.h"
13
14 /**
15 Disables the 32-bit paging mode on the CPU.
16
17 Disables the 32-bit paging mode on the CPU and returns to 32-bit protected
18 mode. This function assumes the current execution mode is 32-paged protected
19 mode. This function is only available on IA-32. After the 32-bit paging mode
20 is disabled, control is transferred to the function specified by EntryPoint
21 using the new stack specified by NewStack and passing in the parameters
22 specified by Context1 and Context2. Context1 and Context2 are optional and
23 may be NULL. The function EntryPoint must never return.
24
25 If the current execution mode is not 32-bit paged mode, then ASSERT().
26 If EntryPoint is NULL, then ASSERT().
27 If NewStack is NULL, then ASSERT().
28
29 There are a number of constraints that must be followed before calling this
30 function:
31 1) Interrupts must be disabled.
32 2) The caller must be in 32-bit paged mode.
33 3) CR0, CR3, and CR4 must be compatible with 32-bit paged mode.
34 4) CR3 must point to valid page tables that guarantee that the pages for
35 this function and the stack are identity mapped.
36
37 @param EntryPoint A pointer to function to call with the new stack after
38 paging is disabled.
39 @param Context1 A pointer to the context to pass into the EntryPoint
40 function as the first parameter after paging is disabled.
41 @param Context2 A pointer to the context to pass into the EntryPoint
42 function as the second parameter after paging is
43 disabled.
44 @param NewStack A pointer to the new stack to use for the EntryPoint
45 function after paging is disabled.
46
47 **/
48 VOID
49 EFIAPI
AsmDisablePaging32(IN SWITCH_STACK_ENTRY_POINT EntryPoint,IN VOID * Context1,OPTIONAL IN VOID * Context2,OPTIONAL IN VOID * NewStack)50 AsmDisablePaging32 (
51 IN SWITCH_STACK_ENTRY_POINT EntryPoint,
52 IN VOID *Context1, OPTIONAL
53 IN VOID *Context2, OPTIONAL
54 IN VOID *NewStack
55 )
56 {
57 ASSERT (EntryPoint != NULL);
58 ASSERT (NewStack != NULL);
59 InternalX86DisablePaging32 (EntryPoint, Context1, Context2, NewStack);
60 }
61