[reactos] 02/02: [NTOS:KE/x64] Fix exception information on page faults

[Timo Kreuzer]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=2913ef5c9300fe1028de0…

commit 2913ef5c9300fe1028de07f238dcb2ed39174edf
Author:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
AuthorDate: Sat Sep 7 23:33:48 2024 +0300
Commit:     Timo Kreuzer <timo.kreuzer(a)reactos.org>
CommitDate: Thu Sep 12 17:07:59 2024 +0300

    [NTOS:KE/x64] Fix exception information on page faults
    
    Pass a proper write/execute flag in the ExceptionInformation[0] field of the exception
record instead of the raw fault code. This fixes comdlg:filedlg wine test, which writes to
a write protected resource section, which needs to be handled by kernel32
UnhandledExceptionFilter, which relies on this parameter to be correct.
---
 ntoskrnl/ke/amd64/trap.S | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/ntoskrnl/ke/amd64/trap.S b/ntoskrnl/ke/amd64/trap.S
index 03e71bf9bc3..34b7c906104 100644
--- a/ntoskrnl/ke/amd64/trap.S
+++ b/ntoskrnl/ke/amd64/trap.S
@@ -461,8 +461,11 @@ IntsDisabled:
 
 PageFaultError:
 
-    /* Set parameter 1 to error code */
+    /* Set parameter 1 to write/execute flag.
+       See
https://learn.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-exceptio… */
     mov r9d, [rbp + KTRAP_FRAME_ErrorCode]
+    shr r9d, 1
+    and r9d, 9
 
     /* Set parameter 2 to faulting address */
     mov r10, cr2  // Param2 = faulting address