ntdll: Add a helper function to retrieve the CPU area context on the Unix side.

dlls/ntdll/unix/signal_arm.c

@@ -921,11 +921,7 @@ void DECLSPEC_HIDDEN call_init_thunk( LPTHREAD_START_ROUTINE entry, void *arg, B
     context.Sp = (DWORD)teb->Tib.StackBase;
     context.Pc = (DWORD)pRtlUserThreadStart;
     if (context.Pc & 1) context.Cpsr |= 0x20; /* thumb mode */
-    if (NtCurrentTeb64())
-    {
-        WOW64_CPURESERVED *cpu = ULongToPtr( NtCurrentTeb64()->TlsSlots[WOW64_TLS_CPURESERVED] );
-        memcpy( cpu + 1, &context, sizeof(context) );
-    }
+    if ((ctx = get_cpu_area( IMAGE_FILE_MACHINE_ARMNT ))) *ctx = context;
 
     if (suspend) wait_suspend( &context );
 

dlls/ntdll/unix/signal_i386.c

@@ -2337,11 +2337,7 @@ void DECLSPEC_HIDDEN call_init_thunk( LPTHREAD_START_ROUTINE entry, void *arg, B
     context.FloatSave.ControlWord = 0x27f;
     ((XSAVE_FORMAT *)context.ExtendedRegisters)->ControlWord = 0x27f;
     ((XSAVE_FORMAT *)context.ExtendedRegisters)->MxCsr = 0x1f80;
-    if (NtCurrentTeb64())
-    {
-        WOW64_CPURESERVED *cpu = ULongToPtr( NtCurrentTeb64()->TlsSlots[WOW64_TLS_CPURESERVED] );
-        memcpy( cpu + 1, &context, sizeof(context) );
-    }
+    if ((ctx = get_cpu_area( IMAGE_FILE_MACHINE_I386 ))) *ctx = context;
 
     if (suspend) wait_suspend( &context );
 

dlls/ntdll/unix/thread.c

@@ -1098,6 +1098,35 @@ static SIZE_T get_machine_context_size( USHORT machine )
 
 
 /***********************************************************************
+ *           get_cpu_area
+ *
+ * cf. RtlWow64GetCurrentCpuArea
+ */
+void *get_cpu_area( USHORT machine )
+{
+    WOW64_CPURESERVED *cpu;
+    ULONG align;
+
+    if (!NtCurrentTeb()->WowTebOffset) return NULL;
+#ifdef _WIN64
+    cpu = NtCurrentTeb()->TlsSlots[WOW64_TLS_CPURESERVED];
+#else
+    cpu = ULongToPtr( NtCurrentTeb64()->TlsSlots[WOW64_TLS_CPURESERVED] );
+#endif
+    if (cpu->Machine != machine) return NULL;
+    switch (cpu->Machine)
+    {
+    case IMAGE_FILE_MACHINE_I386: align = TYPE_ALIGNMENT(I386_CONTEXT); break;
+    case IMAGE_FILE_MACHINE_AMD64: align = TYPE_ALIGNMENT(ARM_CONTEXT); break;
+    case IMAGE_FILE_MACHINE_ARMNT: align = TYPE_ALIGNMENT(AMD64_CONTEXT); break;
+    case IMAGE_FILE_MACHINE_ARM64: align = TYPE_ALIGNMENT(ARM64_NT_CONTEXT); break;
+    default: return NULL;
+    }
+    return (void *)(((ULONG_PTR)(cpu + 1) + align - 1) & ~(align - 1));
+}
+
+
+/***********************************************************************
  *           set_thread_id
  */
 void set_thread_id( TEB *teb, DWORD pid, DWORD tid )

dlls/ntdll/unix/unix_private.h

@@ -181,6 +181,7 @@ extern int server_pipe( int fd[2] ) DECLSPEC_HIDDEN;
 
 extern void fpux_to_fpu( I386_FLOATING_SAVE_AREA *fpu, const XSAVE_FORMAT *fpux ) DECLSPEC_HIDDEN;
 extern void fpu_to_fpux( XSAVE_FORMAT *fpux, const I386_FLOATING_SAVE_AREA *fpu ) DECLSPEC_HIDDEN;
+extern void *get_cpu_area( USHORT machine ) DECLSPEC_HIDDEN;
 extern void set_thread_id( TEB *teb, DWORD pid, DWORD tid ) DECLSPEC_HIDDEN;
 extern NTSTATUS init_thread_stack( TEB *teb, ULONG_PTR zero_bits, SIZE_T reserve_size, SIZE_T commit_size ) DECLSPEC_HIDDEN;
 extern void DECLSPEC_NORETURN abort_thread( int status ) DECLSPEC_HIDDEN;