[MIPS] Restore the trusted stack in NaClSyscallSeg.

src/trusted/service_runtime/arch/mips/sel_rt.c

Index: src/trusted/service_runtime/arch/mips/sel_rt.c
diff --git a/src/trusted/service_runtime/arch/mips/sel_rt.c b/src/trusted/service_runtime/arch/mips/sel_rt.c
index 37e0d7e68eb46e79c57e08746e9b5102a5c4a69d..f2cd8327501310313fc7a645384f2c3357f6dca6 100644
--- a/src/trusted/service_runtime/arch/mips/sel_rt.c
+++ b/src/trusted/service_runtime/arch/mips/sel_rt.c
@@ -1,7 +1,7 @@
 /*
- * Copyright 2012 The Native Client Authors. All rights reserved.
- * Use of this source code is governed by a BSD-style license that can
- * be found in the LICENSE file.
+ * Copyright (c) 2012 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
  */
 
 /*
@@ -90,7 +90,7 @@ void NaClThreadContextToSignalContext(const struct NaClThreadContext *th_ctx,
   sig_ctx->t9          = 0;
   sig_ctx->k0          = 0;
   sig_ctx->k1          = 0;
-  sig_ctx->global_ptr  = th_ctx->global_ptr;
+  sig_ctx->global_ptr  = 0;
   sig_ctx->stack_ptr   = th_ctx->stack_ptr;
   sig_ctx->frame_ptr   = th_ctx->frame_ptr;
   sig_ctx->return_addr = th_ctx->prog_ctr;