[PATCH v5 3/3] ntdll: Handle invalid FP state in usr1_handler() on i386.

[Paul Gofman]

From: Paul Gofman

---
 dlls/ntdll/unix/signal_i386.c | 73 +++++++++++++++++++++++++++++++----
 1 file changed, 66 insertions(+), 7 deletions(-)

diff --git a/dlls/ntdll/unix/signal_i386.c b/dlls/ntdll/unix/signal_i386.c
index 92a01bb37cb..d4fac225430 100644
--- a/dlls/ntdll/unix/signal_i386.c
+++ b/dlls/ntdll/unix/signal_i386.c
@@ -505,6 +505,8 @@ struct syscall_frame

C_ASSERT( sizeof(struct syscall_frame) == 0x280 );

+#define RESTORE_FLAGS_INCOMPLETE_FRAME_CONTEXT 0x00008000
+
 struct x86_thread_data
 {
     UINT               fs;            /* 1d4 TEB selector */
@@ -716,7 +718,7 @@ static inline void *init_handler( const ucontext_t *sigcontext )
  *
  * Save the thread FPU context.
  */
-static inline void save_fpu( CONTEXT *context )
+static inline void save_fpu( I386_FLOATING_SAVE_AREA *fsave )
 {
     struct
     {
@@ -730,11 +732,10 @@ static inline void save_fpu( CONTEXT *context )
     }
     float_status;

-    context->ContextFlags |= CONTEXT_FLOATING_POINT;
-    __asm__ __volatile__( "fnsave %0; fwait" : "=m" (context->FloatSave) );
+    __asm__ __volatile__( "fnsave %0; fwait" : "=m" (*fsave) );

/* Reset unmasked exceptions status to avoid firing an exception. */
-    memcpy(&float_status, &context->FloatSave, sizeof(float_status));
+    memcpy(&float_status, fsave, sizeof(float_status));
     float_status.StatusWord &= float_status.ControlWord | 0xffffff80;

__asm__ __volatile__( "fldenv %0" : : "m" (float_status) );
@@ -805,7 +806,58 @@ static inline void save_context( struct xcontext *xcontext, const ucontext_t *si
         if (!fpu) fpux_to_fpu( &context->FloatSave, fpux );
         if (xstate_extended_features && (xs = XState_sig(fpux))) context_init_xstate( context, xs );
     }
-    if (!fpu && !fpux) save_fpu( context );
+    if (!fpu && !fpux)
+    {
+        save_fpu( &context->FloatSave );
+        context->ContextFlags |= CONTEXT_FLOATING_POINT;
+    }
+}
+
+
+/***********************************************************************
+ *           fixup_frame_fpu_state
+ *
+ * Set FP frame state not saved in __wine_unix_call_dispatcher from sigcontext.
+ */
+static void fixup_frame_fpu_state( struct syscall_frame *frame, const ucontext_t *sigcontext )
+{
+    memset( &frame->xstate, 0, sizeof(frame->xstate) );
+    if (user_shared_data->XState.CompactionEnabled)
+        frame->xstate.CompactionMask = 0x8000000000000000 | user_shared_data->XState.EnabledFeatures;
+    if (FPUX_sig(sigcontext))
+    {
+        if (user_shared_data->ProcessorFeatures[PF_XMMI_INSTRUCTIONS_AVAILABLE])
+            frame->u.xsave = *FPUX_sig(sigcontext);
+        else
+            fpux_to_fpu( &frame->u.fsave, FPUX_sig(sigcontext) );
+        frame->xstate.Mask = XSTATE_MASK_LEGACY;
+    }
+    else
+    {
+        I386_FLOATING_SAVE_AREA *fsave, fsave_buf;
+
+        if (FPU_sig(sigcontext)) fsave = FPU_sig(sigcontext);
+        else
+        {
+            save_fpu( &fsave_buf );
+            fsave = &fsave_buf;
+        }
+        if (user_shared_data->ProcessorFeatures[PF_XMMI_INSTRUCTIONS_AVAILABLE])
+            fpu_to_fpux( &frame->u.xsave, fsave );
+        else
+            frame->u.fsave = *fsave;
+    }
+    /* Clear register stack. */
+    if (user_shared_data->ProcessorFeatures[PF_XMMI_INSTRUCTIONS_AVAILABLE])
+    {
+        frame->u.xsave.TagWord = 0;
+        frame->u.xsave.StatusWord = 0;
+    }
+    else
+    {
+        frame->u.fsave.TagWord = 0xffffffff;
+        frame->u.fsave.StatusWord = 0xffff0000;
+    }
 }

@@ -1865,6 +1917,7 @@ static BOOL handle_syscall_trap( ucontext_t *sigcontext, siginfo_t *siginfo )
         extern void __wine_unix_call_dispatcher_prolog_end(void);

EIP_sig( sigcontext ) = (ULONG)__wine_unix_call_dispatcher_prolog_end;
+        fixup_frame_fpu_state( frame, sigcontext );
     }
     else if (siginfo->si_code == 4 /* TRAP_HWBKPT */ && is_inside_syscall( ESP_sig(sigcontext) ))
     {
@@ -2135,6 +2188,12 @@ static void usr1_handler( int signal, siginfo_t *siginfo, void *sigcontext )
             return;
         }
         context->c.ContextFlags = CONTEXT_FULL | CONTEXT_EXCEPTION_REQUEST;
+        if (frame->restore_flags & RESTORE_FLAGS_INCOMPLETE_FRAME_CONTEXT)
+        {
+            frame->restore_flags &= ~RESTORE_FLAGS_INCOMPLETE_FRAME_CONTEXT;
+            frame->eflags = 0x202;
+            fixup_frame_fpu_state( frame, ucontext );
+        }
         NtGetContextThread( GetCurrentThread(), &context->c );
         if (xstate_extended_features)
         {
@@ -2697,7 +2756,7 @@ __ASM_GLOBAL_FUNC( __wine_syscall_dispatcher_return,
  */
 __ASM_GLOBAL_FUNC( __wine_unix_call_dispatcher,
                    "movl %fs:0x218,%ecx\n\t"   /* thread_data->syscall_frame */
-                   "movl $0,(%ecx)\n\t"        /* frame->restore_flags */
+                   "movl $0x8000,(%ecx)\n\t"   /* frame->restore_flags <- RESTORE_FLAGS_INCOMPLETE_FRAME_CONTEXT */
                    "popl 0x08(%ecx)\n\t"       /* frame->eip */
                    __ASM_CFI(".cfi_adjust_cfa_offset -4\n\t")
                    __ASM_CFI_REG_IS_AT1(eip, ecx, 0x08)
@@ -2734,7 +2793,7 @@ __ASM_GLOBAL_FUNC( __wine_unix_call_dispatcher,
                    __ASM_CFI(".cfi_offset %edi,-20\n\t")
                    "call *(%eax,%edx,4)\n\t"
                    "leal 16(%esp),%esp\n\t"
-                   "testl $0xffff,(%esp)\n\t"  /* frame->restore_flags */
+                   "testl $0x7fff,(%esp)\n\t"  /* frame->restore_flags */
                    "jnz " __ASM_LOCAL_LABEL("__wine_syscall_dispatcher_return") "\n\t"
                    "movl 0x08(%esp),%ecx\n\t"  /* frame->eip */
                    /* switch to user stack */