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102 lines
2.6 KiB
102 lines
2.6 KiB
/** @file
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Implementation of SetJump() on IA-32.
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Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
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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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**/
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#include "BaseLibInternals.h"
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/**
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Worker function that checks ASSERT condition for JumpBuffer
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Checks ASSERT condition for JumpBuffer.
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If JumpBuffer is NULL, then ASSERT().
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For IPF CPUs, if JumpBuffer is not aligned on a 16-byte boundary, then ASSERT().
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@param JumpBuffer A pointer to CPU context buffer.
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**/
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VOID
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EFIAPI
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InternalAssertJumpBuffer (
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IN BASE_LIBRARY_JUMP_BUFFER *JumpBuffer
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);
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/**
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Saves the current CPU context that can be restored with a call to LongJump()
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and returns 0.
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Saves the current CPU context in the buffer specified by JumpBuffer and
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returns 0. The initial call to SetJump() must always return 0. Subsequent
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calls to LongJump() cause a non-zero value to be returned by SetJump().
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If JumpBuffer is NULL, then ASSERT().
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For IPF CPUs, if JumpBuffer is not aligned on a 16-byte boundary, then ASSERT().
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@param JumpBuffer A pointer to CPU context buffer.
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@retval 0 Indicates a return from SetJump().
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**/
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_declspec (naked)
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RETURNS_TWICE
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UINTN
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EFIAPI
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SetJump (
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OUT BASE_LIBRARY_JUMP_BUFFER *JumpBuffer
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)
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{
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_asm {
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push [esp + 4]
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call InternalAssertJumpBuffer
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pop ecx
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pop ecx
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mov edx, [esp]
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xor eax, eax
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mov [edx + 24], eax ; save 0 to SSP
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mov eax, [PcdGet32 (PcdControlFlowEnforcementPropertyMask)]
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test eax, eax
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jz CetDone
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_emit 0x0F
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_emit 0x20
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_emit 0xE0 ; mov eax, cr4
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bt eax, 23 ; check if CET is enabled
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jnc CetDone
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mov eax, 1
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_emit 0xF3
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_emit 0x0F
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_emit 0xAE
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_emit 0xE8 ; INCSSP EAX to read original SSP
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_emit 0xF3
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_emit 0x0F
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_emit 0x1E
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_emit 0xC8 ; READSSP EAX
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mov [edx + 0x24], eax ; save SSP
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CetDone:
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mov [edx], ebx
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mov [edx + 4], esi
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mov [edx + 8], edi
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mov [edx + 12], ebp
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mov [edx + 16], esp
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mov [edx + 20], ecx
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xor eax, eax
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jmp ecx
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}
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}
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