[ARM] ptrace: clean up single stepping support

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/ptrace.h b/arch/arm/kernel/ptrace.h
index f7cad13..def3b61 100644
--- a/arch/arm/kernel/ptrace.h
+++ b/arch/arm/kernel/ptrace.h
@@ -7,6 +7,45 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
+#include <linux/ptrace.h>
+
 extern void ptrace_cancel_bpt(struct task_struct *);
 extern void ptrace_set_bpt(struct task_struct *);
 extern void ptrace_break(struct task_struct *, struct pt_regs *);
+
+/*
+ * make sure single-step breakpoint is gone.
+ */
+static inline void single_step_disable(struct task_struct *task)
+{
+	task->ptrace &= ~PT_SINGLESTEP;
+	ptrace_cancel_bpt(task);
+}
+
+static inline void single_step_enable(struct task_struct *task)
+{
+	task->ptrace |= PT_SINGLESTEP;
+}
+
+/*
+ * Send SIGTRAP if we're single-stepping
+ */
+static inline void single_step_trap(struct task_struct *task)
+{
+	if (task->ptrace & PT_SINGLESTEP) {
+		ptrace_cancel_bpt(task);
+		send_sig(SIGTRAP, task, 1);
+	}
+}
+
+static inline void single_step_clear(struct task_struct *task)
+{
+	if (task->ptrace & PT_SINGLESTEP)
+		ptrace_cancel_bpt(task);
+}
+
+static inline void single_step_set(struct task_struct *task)
+{
+	if (task->ptrace & PT_SINGLESTEP)
+		ptrace_set_bpt(task);
+}