1 files changed, 11 insertions, 4 deletions

diff --git a/arch/sh/kernel/sh_bios.c b/arch/sh/kernel/sh_bios.c
index 29cd2526e5c4..47475cca068a 100644
--- a/arch/sh/kernel/sh_bios.c
+++ b/arch/sh/kernel/sh_bios.c
@@ -23,6 +23,8 @@
 #define BIOS_CALL_SHUTDOWN              11
 #define BIOS_CALL_GDB_DETACH            0xff
 
+void *gdb_vbr_vector = NULL;
+
 static inline long sh_bios_call(long func, long arg0, long arg1, long arg2,
                                     long arg3)
 {
@@ -32,6 +34,9 @@ static inline long sh_bios_call(long func, long arg0, long arg1, long arg2,
         register long r6 __asm__("r6") = arg2;
         register long r7 __asm__("r7") = arg3;
 
+        if (!gdb_vbr_vector)
+                return -ENOSYS;
+
         __asm__ __volatile__("trapa     #0x3f":"=z"(r0)
                              :"0"(r0), "r"(r4), "r"(r5), "r"(r6), "r"(r7)
                              :"memory");
@@ -60,8 +65,6 @@ void sh_bios_shutdown(unsigned int how)
         sh_bios_call(BIOS_CALL_SHUTDOWN, how, 0, 0, 0);
 }
 
-void *gdb_vbr_vector = NULL;
-
 /*
  * Read the old value of the VBR register to initialise the vector
  * through which debug and BIOS traps are delegated by the Linux trap
@@ -76,8 +79,12 @@ void sh_bios_vbr_init(void)
 
         __asm__ __volatile__ ("stc vbr, %0" : "=r" (vbr));
 
-        gdb_vbr_vector = (void *)(vbr + 0x100);
-        printk(KERN_NOTICE "Setting GDB trap vector to %p\n", gdb_vbr_vector);
+        if (vbr) {
+                gdb_vbr_vector = (void *)(vbr + 0x100);
+                printk(KERN_NOTICE "Setting GDB trap vector to %p\n",
+                       gdb_vbr_vector);
+        } else
+                printk(KERN_NOTICE "SH-BIOS not detected\n");
 }
 
 /**