[reactos] 09/15: [NTOS:KE] Save and restore previous mode in KiZwSystemService and fix restoring the trap frame

[Timo Kreuzer]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=3aaee3562910cd0611356…

commit 3aaee3562910cd06113569cace4eb155ee2a6050
Author:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
AuthorDate: Mon Feb 5 01:23:30 2018 +0100
Commit:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
CommitDate: Sun Sep 20 23:08:17 2020 +0200

    [NTOS:KE] Save and restore previous mode in KiZwSystemService and fix restoring the
trap frame
---
 ntoskrnl/ke/amd64/trap.S | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/ntoskrnl/ke/amd64/trap.S b/ntoskrnl/ke/amd64/trap.S
index 15f816f756b..3bcaa1684bf 100644
--- a/ntoskrnl/ke/amd64/trap.S
+++ b/ntoskrnl/ke/amd64/trap.S
@@ -835,6 +835,10 @@ FUNC KiZwSystemService
     /* Get current thread */
     mov r11, gs:[PcCurrentThread]
 
+    /* Save PreviousMode in the trap frame */
+    mov dil, byte ptr [r11 + KTHREAD_PreviousMode]
+    mov byte ptr [rbp + KTRAP_FRAME_PreviousMode], dil
+
     /* Save the old trap frame in TrapFrame.Rdx */
     mov rdi, [r11 + KTHREAD_TrapFrame]
     mov [rbp + KTRAP_FRAME_Rdx], rdi
@@ -865,9 +869,13 @@ FUNC KiZwSystemService
 
     /* Restore the old trap frame */
     mov r11, gs:[PcCurrentThread]
-    mov rsi, [rsp + KTRAP_FRAME_Rdx]
+    mov rsi, [rbp + KTRAP_FRAME_Rdx]
     mov [r11 + KTHREAD_TrapFrame], rsi
 
+    /* Restore PreviousMode from the trap frame */
+    mov dil, byte ptr [rbp + KTRAP_FRAME_PreviousMode]
+    mov byte ptr [r11 + KTHREAD_PreviousMode], dil
+
     /* Restore rdi and rsi */
     mov rsi, [rbp + KTRAP_FRAME_Rsi]
     mov rdi, [rbp + KTRAP_FRAME_Rdi]