[MIPS] Implementation of sel_ldr for MIPS architecture.

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

Index: src/trusted/service_runtime/arch/mips/nacl_switch_to_app_mips.c
diff --git a/src/trusted/service_runtime/arch/arm/nacl_switch_to_app_arm.c b/src/trusted/service_runtime/arch/mips/nacl_switch_to_app_mips.c
similarity index 79%
copy from src/trusted/service_runtime/arch/arm/nacl_switch_to_app_arm.c
copy to src/trusted/service_runtime/arch/mips/nacl_switch_to_app_mips.c
index 9a2f913f82105af85ebe669f4d14efbe75cfe0ed..fc750fe4a20aabc823867d8569dfe04387e8d87d 100644
--- a/src/trusted/service_runtime/arch/arm/nacl_switch_to_app_arm.c
+++ b/src/trusted/service_runtime/arch/mips/nacl_switch_to_app_mips.c
@@ -9,26 +9,27 @@
  */
 
 #include "native_client/src/shared/platform/nacl_check.h"
-#include "native_client/src/trusted/service_runtime/sel_ldr.h"
-#include "native_client/src/trusted/service_runtime/arch/arm/sel_rt.h"
+#include "native_client/src/trusted/service_runtime/arch/mips/sel_rt.h"
 #include "native_client/src/trusted/service_runtime/nacl_app_thread.h"
 #include "native_client/src/trusted/service_runtime/nacl_globals.h"
 #include "native_client/src/trusted/service_runtime/nacl_switch_to_app.h"
+#include "native_client/src/trusted/service_runtime/sel_ldr.h"
 
 void NaClInitSwitchToApp(struct NaClApp *nap) {
-  /*
-   * We don't need anything here.  We might need it in future if e.g.
-   * we start letting untrusted code use NEON extensions.
-   */
+ /*
+  * We don't need anything here.
+  */
   UNREFERENCED_PARAMETER(nap);
 }
 
 NORETURN void NaClStartThreadInApp(struct NaClAppThread *natp,
                                    uint32_t             new_prog_ctr) {
+  struct NaClApp  *nap;
   struct NaClThreadContext  *context;
 
-  natp->user.trusted_stack_ptr = NaClGetStackPtr() & ~0xf;
+  natp->user.trusted_stack_ptr = (NaClGetStackPtr() & ~0xf) + 4;
 
+  nap = natp->nap;
   context = &natp->user;
   context->new_prog_ctr = new_prog_ctr;
 
@@ -41,6 +42,14 @@ NORETURN void NaClStartThreadInApp(struct NaClAppThread *natp,
    */
   context->sysret = context->stack_ptr;
 
+  /*
+   * Just to be sure that app does not spoil gp
+   */
+  context->global_ptr = NaClGetGlobalPtr();
+
+  /*
+   * context stored in $a0
+   */
   NaClSwitch(context);
 }