From 786ae7688414d58a14ef68b023af4b040f37323e Mon Sep 17 00:00:00 2001
From: Hongbin1 Zhang <hongbin1.zhang@intel.com>
Date: Mon, 3 Mar 2025 13:06:26 +0800
Subject: [PATCH] IntelFsp2WrapperPkg: Bootloader need to recover fs and gs

When enter FSP, bootloader need to save fs and gs, when back
to bootloader, bootloader need to restore fs and gs, so it
could avoid bootloader access wrong data segment when usging
fs and gs.

Signed-off-by: Hongbin1 Zhang <hongbin1.zhang@intel.com>
Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Duggapu Chinni B <chinni.b.duggapu@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Ted Kuo <ted.kuo@intel.com>
Cc: Ashraf Ali S <ashraf.ali.s@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
---
 .../Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm     | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm b/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm
index db8e62ebc5..a65bb103b1 100644
--- a/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm
+++ b/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm
@@ -110,9 +110,11 @@ ASM_PFX(AsmExecute32BitCode):
     retf
 
 Compatible:
-    ; reload DS/ES/SS to make sure they are correct referred to current GDT
+    ; reload DS/ES/FS/GS/SS to make sure they are correct referred to current GDT
     mov     ds, ax
     mov     es, ax
+    mov     fs, ax
+    mov     gs, ax
     mov     ss, ax
 
     ;
@@ -208,11 +210,13 @@ ReloadCS:
     retf
 .0:
     ;
-    ; Reload original DS/ES/SS
+    ; Reload original DS/ES/FS/GS/SS
     ;
     pop     rcx
     mov     ds, rcx
     mov     es, rcx
+    mov     fs, rcx
+    mov     gs, rcx
     mov     ss, rcx
 
     ;