kgdb,sh: update superh kgdb exception handling

Implement kgdb_arch_pc() which adjusts the pc if it needs to be
adjusted after a software breakpoint trap.

Implement kgdb_arch_set_pc() which is a new required function in the
kgdb debug core.

When processing a single step return zero in the error exception field
so that the debug core can distinguish between a single step trap and
a breakpoint trap generically.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Acked-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/kernel/kgdb.c

@@ -237,6 +237,18 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
 	return -1;
 }
 
+unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+	if (exception == 60)
+		return instruction_pointer(regs) - 2;
+	return instruction_pointer(regs);
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+	regs->pc = ip;
+}
+
 /*
  * The primary entry points for the kgdb debug trap table entries.
  */
@@ -247,7 +259,7 @@ BUILD_TRAP_HANDLER(singlestep)
 
 	local_irq_save(flags);
 	regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
-	kgdb_handle_exception(vec >> 2, SIGTRAP, 0, regs);
+	kgdb_handle_exception(0, SIGTRAP, 0, regs);
 	local_irq_restore(flags);
 }