mirror of https://github.com/acidanthera/audk.git
66 lines
2.7 KiB
C
66 lines
2.7 KiB
C
/** @file
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IA-32/x64 AsmDisablePaging32()
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Copyright (c) 2006, Intel Corporation<BR>
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All rights reserved. This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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Module Name: x86DisablePaging32.c
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**/
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#include "BaseLibInternals.h"
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/**
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Disables the 32-bit paging mode on the CPU.
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Disables the 32-bit paging mode on the CPU and returns to 32-bit protected
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mode. This function assumes the current execution mode is 32-paged protected
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mode. This function is only available on IA-32. After the 32-bit paging mode
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is disabled, control is transferred to the function specified by EntryPoint
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using the new stack specified by NewStack and passing in the parameters
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specified by Context1 and Context2. Context1 and Context2 are optional and
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may be NULL. The function EntryPoint must never return.
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If the current execution mode is not 32-bit paged mode, then ASSERT().
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If EntryPoint is NULL, then ASSERT().
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If NewStack is NULL, then ASSERT().
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There are a number of constraints that must be followed before calling this
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function:
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1) Interrupts must be disabled.
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2) The caller must be in 32-bit paged mode.
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3) CR0, CR3, and CR4 must be compatible with 32-bit paged mode.
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4) CR3 must point to valid page tables that guarantee that the pages for
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this function and the stack are identity mapped.
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@param EntryPoint A pointer to function to call with the new stack after
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paging is disabled.
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@param Context1 A pointer to the context to pass into the EntryPoint
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function as the first parameter after paging is disabled.
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@param Context2 A pointer to the context to pass into the EntryPoint
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function as the second parameter after paging is
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disabled.
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@param NewStack A pointer to the new stack to use for the EntryPoint
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function after paging is disabled.
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**/
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VOID
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EFIAPI
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AsmDisablePaging32 (
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IN SWITCH_STACK_ENTRY_POINT EntryPoint,
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IN VOID *Context1, OPTIONAL
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IN VOID *Context2, OPTIONAL
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IN VOID *NewStack
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)
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{
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ASSERT (EntryPoint != NULL);
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ASSERT (NewStack != NULL);
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InternalX86DisablePaging32 (EntryPoint, Context1, Context2, NewStack);
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}
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