UefiCpuPkg/MpInitLib: Disable interrupt at ExitBootServices AP Mwait

Within function ApWakeupFunction():

When source level debugger is enabled, AP interrupts will be enabled by
EnableDebugAgent(). Then the AP function will be executed by:

Procedure (Parameter);

After the AP function returns, AP interrupts will be disabled when the
APs are placed in loop mode (both HltLoop and MwaiLoop).

However, at ExitBootServices, ApWakeupFunction() is called with
'Procedure' equals to RelocateApLoop().

(ExitBootServices callback registered within InitMpGlobalData())

RelocateApLoop() never returns, so it has to disable the AP interrupts by
itself. However, we find that interrupts are only disabled for the
HltLoop case, but not for the MwaitLoop case (within file MpFuncs.nasm).

This commit adds the missing disabling of AP interrupts for MwaitLoop.

Also, for X64, this commit will disable the interrupts before switching to
32-bit mode.

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Jeff Fan <vanjeff_919@hotmail.com>

2 files changed, 5 insertions, 2 deletions

diff --git a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
index bd79be0f5e..59e88d3f8f 100644
--- a/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
+++ b/UefiCpuPkg/Library/MpInitLib/Ia32/MpFuncs.nasm
@@ -1,5 +1,5 @@
 ;------------------------------------------------------------------------------ ;

-; Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>

+; Copyright (c) 2015 - 2018, 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

@@ -239,6 +239,7 @@ AsmRelocateApLoopStart:
     cmp        cl,  1              ; Check mwait-monitor support

     jnz        HltLoop

 MwaitLoop:

+    cli

     mov        eax, esp

     xor        ecx, ecx

     xor        edx, edx

diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
index 7595988884..76f8c078ab 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
+++ b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
@@ -1,5 +1,5 @@
 ;------------------------------------------------------------------------------ ;

-; Copyright (c) 2015 - 2017, Intel Corporation. All rights reserved.<BR>

+; Copyright (c) 2015 - 2018, 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

@@ -253,6 +253,7 @@ RendezvousFunnelProcEnd:
 global ASM_PFX(AsmRelocateApLoop)

 ASM_PFX(AsmRelocateApLoop):

 AsmRelocateApLoopStart:

+    cli                          ; Disable interrupt before switching to 32-bit mode

     mov        rax, [rsp + 40]   ; CountTofinish

     lock dec   dword [rax]       ; (*CountTofinish)--

     mov        rsp, r9

@@ -288,6 +289,7 @@ PmEntry:
     jnz        HltLoop

     mov        ebx, edx           ; Save C-State to ebx

 MwaitLoop:

+    cli

     mov        eax, esp           ; Set Monitor Address

     xor        ecx, ecx           ; ecx = 0

     xor        edx, edx           ; edx = 0