ntdll: Don't restore %fs selector on nested signals.

dlls/ntdll/unix/signal_x86_64.c

@@ -1542,7 +1542,8 @@ static inline void init_handler( const ucontext_t *sigcontext )
 static inline void leave_handler( const ucontext_t *sigcontext )
 {
 #ifdef __linux__
-    if (fs32_sel) __asm__ volatile( "movw %0,%%fs" :: "r" (fs32_sel) );
+    if (fs32_sel && !is_inside_signal_stack( (void *)RSP_sig(sigcontext )))
+        __asm__ volatile( "movw %0,%%fs" :: "r" (fs32_sel) );
 #endif
 }
 
@@ -1997,7 +1998,7 @@ NTSTATUS set_thread_wow64_context( HANDLE handle, const void *ctx, ULONG size )
             memcpy( &frame->xstate.YmmContext, &xs->YmmContext, sizeof(xs->YmmContext) );
         }
         else frame->xstate.Mask &= ~XSTATE_MASK_GSSE;
-        frame->restore_flags |= CONTEXT_I386_XSTATE;
+        frame->restore_flags |= CONTEXT_XSTATE;
     }
     return STATUS_SUCCESS;
 }

dlls/ntdll/unix/unix_private.h

@@ -318,6 +318,12 @@ static inline void *get_signal_stack(void)
     return (void *)(((ULONG_PTR)NtCurrentTeb() & ~signal_stack_mask) + teb_size);
 }
 
+static inline BOOL is_inside_signal_stack( void *ptr )
+{
+    return ((char *)ptr >= (char *)get_signal_stack() &&
+            (char *)ptr < (char *)get_signal_stack() + signal_stack_size);
+}
+
 static inline void mutex_lock( pthread_mutex_t *mutex )
 {
     if (!process_exiting) pthread_mutex_lock( mutex );

dlls/ntdll/unix/virtual.c

@@ -237,12 +237,6 @@ static struct range_entry *free_ranges;
 static struct range_entry *free_ranges_end;
 
 
-static inline BOOL is_inside_signal_stack( void *ptr )
-{
-    return ((char *)ptr >= (char *)get_signal_stack() &&
-            (char *)ptr < (char *)get_signal_stack() + signal_stack_size);
-}
-
 static inline BOOL is_beyond_limit( const void *addr, size_t size, const void *limit )
 {
     return (addr >= limit || (const char *)addr + size > (const char *)limit);