sparc: Add kgdb support.

Current limitations:

1) On SMP single stepping has some fundamental issues,
   shared with other sw single-step architectures such
   as mips and arm.

2) On 32-bit sparc we don't support SMP kgdb yet.  That
   requires some reworking of the IPI mechanisms and
   infrastructure on that platform.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/asm-sparc64/ttable.h b/include/asm-sparc64/ttable.h
index d3cc4ef..1b55538 100644
--- a/include/asm-sparc64/ttable.h
+++ b/include/asm-sparc64/ttable.h
@@ -175,6 +175,12 @@
 #define KPROBES_TRAP(lvl) TRAP_ARG(bad_trap, lvl)
 #endif
 
+#ifdef CONFIG_KGDB
+#define KGDB_TRAP(lvl) TRAP_IRQ(kgdb_trap, lvl)
+#else
+#define KGDB_TRAP(lvl) TRAP_ARG(bad_trap, lvl)
+#endif
+
 #define SUN4V_ITSB_MISS					\
 	ldxa	[%g0] ASI_SCRATCHPAD, %g2;		\
 	ldx	[%g2 + HV_FAULT_I_ADDR_OFFSET], %g4;	\