[ARM] ptrace: clean up single stepping support

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 48 insertions, 28 deletions

diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index 9254ba2f46fc..e594b84cca83 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -457,13 +457,10 @@ void ptrace_cancel_bpt(struct task_struct *child)
 
 /*
  * Called by kernel/ptrace.c when detaching..
- *
- * Make sure the single step bit is not set.
  */
 void ptrace_disable(struct task_struct *child)
 {
-        child->ptrace &= ~PT_SINGLESTEP;
-        ptrace_cancel_bpt(child);
+        single_step_disable(child);
 }
 
 /*
@@ -712,9 +709,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                         else
                                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
                         child->exit_code = data;
-                        /* make sure single-step breakpoint is gone. */
-                        child->ptrace &= ~PT_SINGLESTEP;
-                        ptrace_cancel_bpt(child);
+                        single_step_disable(child);
                         wake_up_process(child);
                         ret = 0;
                         break;
@@ -725,9 +720,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                  * exit.
                  */
                 case PTRACE_KILL:
-                        /* make sure single-step breakpoint is gone. */
-                        child->ptrace &= ~PT_SINGLESTEP;
-                        ptrace_cancel_bpt(child);
+                        single_step_disable(child);
                         if (child->exit_state != EXIT_ZOMBIE) {
                                 child->exit_code = SIGKILL;
                                 wake_up_process(child);
@@ -742,7 +735,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
                         ret = -EIO;
                         if (!valid_signal(data))
                                 break;
-                        child->ptrace |= PT_SINGLESTEP;
+                        single_step_enable(child);
                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
                         child->exit_code = data;
                         /* give it a chance to run. */
diff --git a/arch/arm/kernel/ptrace.h b/arch/arm/kernel/ptrace.h
index f7cad13a22e9..def3b6184a79 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);
+}
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 3843d3bab2dd..54cdf1aeefc3 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -9,7 +9,6 @@
  */
 #include <linux/errno.h>
 #include <linux/signal.h>
-#include <linux/ptrace.h>
 #include <linux/personality.h>
 #include <linux/freezer.h>
 
@@ -285,11 +284,7 @@ asmlinkage int sys_sigreturn(struct pt_regs *regs)
         if (restore_sigframe(regs, frame))
                 goto badframe;
 
-        /* Send SIGTRAP if we're single-stepping */
-        if (current->ptrace & PT_SINGLESTEP) {
-                ptrace_cancel_bpt(current);
-                send_sig(SIGTRAP, current, 1);
-        }
+        single_step_trap(current);
 
         return regs->ARM_r0;
 
@@ -324,11 +319,7 @@ asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
         if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
                 goto badframe;
 
-        /* Send SIGTRAP if we're single-stepping */
-        if (current->ptrace & PT_SINGLESTEP) {
-                ptrace_cancel_bpt(current);
-                send_sig(SIGTRAP, current, 1);
-        }
+        single_step_trap(current);
 
         return regs->ARM_r0;
 
@@ -644,14 +635,12 @@ static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
         if (try_to_freeze())
                 goto no_signal;
 
-        if (current->ptrace & PT_SINGLESTEP)
-                ptrace_cancel_bpt(current);
+        single_step_clear(current);
 
         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
         if (signr > 0) {
                 handle_signal(signr, &ka, &info, oldset, regs, syscall);
-                if (current->ptrace & PT_SINGLESTEP)
-                        ptrace_set_bpt(current);
+                single_step_set(current);
                 return 1;
         }
 
@@ -705,8 +694,7 @@ static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
                         restart_syscall(regs);
                 }
         }
-        if (current->ptrace & PT_SINGLESTEP)
-                ptrace_set_bpt(current);
+        single_step_set(current);
         return 0;
 }