From ed725c78b5deb6c482a60ac26eda5f5d58ab531c Mon Sep 17 00:00:00 2001
From: Paul Gofman <pgofman@codeweavers.com>
Date: Tue, 26 Oct 2021 19:07:26 +0300
Subject: [PATCH] ntdll: Don't use Wine frames during exception processing on
 x64.

CW-Bug-ID: #19570
---
 dlls/ntdll/signal_x86_64.c | 65 +++++++++++++++++++++++++++-----------
 1 file changed, 46 insertions(+), 19 deletions(-)

diff --git a/dlls/ntdll/signal_x86_64.c b/dlls/ntdll/signal_x86_64.c
index ac543338893..f2c7cad5675 100644
--- a/dlls/ntdll/signal_x86_64.c
+++ b/dlls/ntdll/signal_x86_64.c
@@ -348,15 +348,32 @@ __ASM_GLOBAL_FUNC( RtlCaptureContext,
                    "fxsave 0x100(%rcx)\n\t"         /* context->FltSave */
                    "ret" );
 
-static DWORD __cdecl nested_exception_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
+DWORD __cdecl nested_exception_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
                                                CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher )
 {
+    TRACE( "exception flags %#x.\n", rec->ExceptionFlags );
+
     if (!(rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND)))
-        rec->ExceptionFlags |= EH_NESTED_CALL;
+        return ExceptionNestedException;
 
     return ExceptionContinueSearch;
 }
 
+/***********************************************************************
+ *		exception_handler_call_wrapper
+ */
+DWORD exception_handler_call_wrapper( EXCEPTION_RECORD *rec, void *frame,
+                                      CONTEXT *context, DISPATCHER_CONTEXT *dispatch );
+__ASM_GLOBAL_FUNC( exception_handler_call_wrapper,
+                   __ASM_SEH(".seh_endprologue\n\t")
+                   "subq $0x28, %rsp\n\t"
+                   __ASM_SEH(".seh_stackalloc 0x28\n\t")
+                   __ASM_SEH(".seh_handler nested_exception_handler, @except\n\t")
+                   "callq *0x30(%r9)\n\t"            /* dispatch->LanguageHandler */
+                   "nop\n\t"
+                   "addq $0x28, %rsp\n\t"
+                   "ret" );
+
 /**********************************************************************
  *           call_handler
  *
@@ -365,19 +382,19 @@ static DWORD __cdecl nested_exception_handler( EXCEPTION_RECORD *rec, EXCEPTION_
  */
 static DWORD call_handler( EXCEPTION_RECORD *rec, CONTEXT *context, DISPATCHER_CONTEXT *dispatch )
 {
-    EXCEPTION_REGISTRATION_RECORD frame;
     DWORD res;
 
-    frame.Handler = nested_exception_handler;
-    __wine_push_frame( &frame );
-
     TRACE_(seh)( "calling handler %p (rec=%p, frame=%p context=%p, dispatch=%p)\n",
                  dispatch->LanguageHandler, rec, (void *)dispatch->EstablisherFrame, dispatch->ContextRecord, dispatch );
-    res = dispatch->LanguageHandler( rec, (void *)dispatch->EstablisherFrame, context, dispatch );
+    res = exception_handler_call_wrapper( rec, (void *)dispatch->EstablisherFrame, context, dispatch );
     TRACE_(seh)( "handler at %p returned %lu\n", dispatch->LanguageHandler, res );
 
     rec->ExceptionFlags &= EH_NONCONTINUABLE;
-    __wine_pop_frame( &frame );
+    if (res == ExceptionNestedException)
+    {
+        rec->ExceptionFlags |= EH_NESTED_CALL;
+        res = ExceptionContinueSearch;
+    }
     return res;
 }
 
@@ -992,7 +1009,8 @@ PVOID WINAPI RtlVirtualUnwind( ULONG type, ULONG64 base, ULONG64 pc,
 
 struct unwind_exception_frame
 {
-    EXCEPTION_REGISTRATION_RECORD frame;
+    BYTE dummy[0x28];
+    void *rip;
     DISPATCHER_CONTEXT *dispatch;
 };
 
@@ -1001,7 +1019,7 @@ struct unwind_exception_frame
  *
  * Handler for exceptions happening while calling an unwind handler.
  */
-static DWORD __cdecl unwind_exception_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
+DWORD __cdecl unwind_exception_handler( EXCEPTION_RECORD *rec, EXCEPTION_REGISTRATION_RECORD *frame,
                                                CONTEXT *context, EXCEPTION_REGISTRATION_RECORD **dispatcher )
 {
     struct unwind_exception_frame *unwind_frame = (struct unwind_exception_frame *)frame;
@@ -1021,27 +1039,36 @@ static DWORD __cdecl unwind_exception_handler( EXCEPTION_RECORD *rec, EXCEPTION_
     return ExceptionCollidedUnwind;
 }
 
+/***********************************************************************
+ *		exception_handler_call_wrapper
+ */
+DWORD unwind_handler_call_wrapper( EXCEPTION_RECORD *rec, void *frame,
+                                      CONTEXT *context, DISPATCHER_CONTEXT *dispatch );
+__ASM_GLOBAL_FUNC( unwind_handler_call_wrapper,
+                   __ASM_SEH(".seh_endprologue\n\t")
+                   "movq %r9, 0x8(%rsp)\n\t"
+                   "subq $0x28, %rsp\n\t"
+                   __ASM_SEH(".seh_stackalloc 0x28\n\t")
+                   __ASM_SEH(".seh_handler unwind_exception_handler, @except, @unwind\n\t")
+                   "callq *0x30(%r9)\n\t"            /* dispatch->LanguageHandler */
+                   "nop\n\t"
+                   "addq $0x28, %rsp\n\t"
+                   "ret" );
+
 /**********************************************************************
  *           call_unwind_handler
  *
  * Call a single unwind handler.
  */
-static DWORD call_unwind_handler( EXCEPTION_RECORD *rec, DISPATCHER_CONTEXT *dispatch )
+DWORD call_unwind_handler( EXCEPTION_RECORD *rec, DISPATCHER_CONTEXT *dispatch )
 {
-    struct unwind_exception_frame frame;
     DWORD res;
 
-    frame.frame.Handler = unwind_exception_handler;
-    frame.dispatch = dispatch;
-    __wine_push_frame( &frame.frame );
-
     TRACE( "calling handler %p (rec=%p, frame=%p context=%p, dispatch=%p)\n",
            dispatch->LanguageHandler, rec, (void *)dispatch->EstablisherFrame, dispatch->ContextRecord, dispatch );
-    res = dispatch->LanguageHandler( rec, (void *)dispatch->EstablisherFrame, dispatch->ContextRecord, dispatch );
+    res = unwind_handler_call_wrapper( rec, (void *)dispatch->EstablisherFrame, dispatch->ContextRecord, dispatch );
     TRACE( "handler %p returned %lx\n", dispatch->LanguageHandler, res );
 
-    __wine_pop_frame( &frame.frame );
-
     switch (res)
     {
     case ExceptionContinueSearch:
-- 
2.38.1