Files
system76-edk2/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
Jian J Wang f32bfe6d06 UefiCpuPkg/MpInitLib: split wake up buffer into two parts
If PcdDxeNxMemoryProtectionPolicy is set to enable protection for memory
of EfiBootServicesCode, EfiConventionalMemory, the BIOS will hang at a page
fault exception during MP initialization.

The root cause is that the AP wake up buffer, which is below 1MB and used
to hold both AP init code and data, is type of EfiConventionalMemory (not
really allocated because of potential conflict with legacy code), and is
marked as non-executable. During the transition from real address mode
to long mode, the AP init code has to enable paging which will then cause
itself a page fault exception because it's just running in non-executable
memory.

The solution is splitting AP wake up buffer into two part: lower part is
still below 1MB and shared with legacy system, higher part is really
allocated memory of BootServicesCode type. The init code in the memory
below 1MB will not enable paging but just switch to protected mode and
jump to higher memory, in which the init code will enable paging and
switch to long mode.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
2018-01-18 17:03:22 +08:00

49 lines
2.3 KiB
PHP

;------------------------------------------------------------------------------ ;
; Copyright (c) 2015 - 2017, 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.
;
; Module Name:
;
; MpEqu.inc
;
; Abstract:
;
; This is the equates file for Multiple Processor support
;
;-------------------------------------------------------------------------------
VacantFlag equ 00h
NotVacantFlag equ 0ffh
CPU_SWITCH_STATE_IDLE equ 0
CPU_SWITCH_STATE_STORED equ 1
CPU_SWITCH_STATE_LOADED equ 2
LockLocation equ (RendezvousFunnelProcEnd - RendezvousFunnelProcStart)
StackStartAddressLocation equ LockLocation + 08h
StackSizeLocation equ LockLocation + 10h
ApProcedureLocation equ LockLocation + 18h
GdtrLocation equ LockLocation + 20h
IdtrLocation equ LockLocation + 2Ah
BufferStartLocation equ LockLocation + 34h
ModeOffsetLocation equ LockLocation + 3Ch
ApIndexLocation equ LockLocation + 44h
CodeSegmentLocation equ LockLocation + 4Ch
DataSegmentLocation equ LockLocation + 54h
EnableExecuteDisableLocation equ LockLocation + 5Ch
Cr3Location equ LockLocation + 64h
InitFlagLocation equ LockLocation + 6Ch
CpuInfoLocation equ LockLocation + 74h
NumApsExecutingLocation equ LockLocation + 7Ch
InitializeFloatingPointUnitsAddress equ LockLocation + 8Ch
ModeTransitionMemoryLocation equ LockLocation + 94h
ModeTransitionSegmentLocation equ LockLocation + 98h
ModeHighMemoryLocation equ LockLocation + 9Ah
ModeHighSegmentLocation equ LockLocation + 9Eh