1 files changed, 35 insertions, 0 deletions

diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 515bff053de8..6ab80714a916 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -204,6 +204,41 @@ static inline void user_enable_block_step(struct task_struct *task)
 }
 #endif  /* arch_has_block_step */
 
+#ifndef arch_ptrace_stop_needed
+/**
+ * arch_ptrace_stop_needed - Decide whether arch_ptrace_stop() should be called
+ * @code:       current->exit_code value ptrace will stop with
+ * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
+ *
+ * This is called with the siglock held, to decide whether or not it's
+ * necessary to release the siglock and call arch_ptrace_stop() with the
+ * same @code and @info arguments.  It can be defined to a constant if
+ * arch_ptrace_stop() is never required, or always is.  On machines where
+ * this makes sense, it should be defined to a quick test to optimize out
+ * calling arch_ptrace_stop() when it would be superfluous.  For example,
+ * if the thread has not been back to user mode since the last stop, the
+ * thread state might indicate that nothing needs to be done.
+ */
+#define arch_ptrace_stop_needed(code, info)     (0)
+#endif
+
+#ifndef arch_ptrace_stop
+/**
+ * arch_ptrace_stop - Do machine-specific work before stopping for ptrace
+ * @code:       current->exit_code value ptrace will stop with
+ * @info:       siginfo_t pointer (or %NULL) for signal ptrace will stop with
+ *
+ * This is called with no locks held when arch_ptrace_stop_needed() has
+ * just returned nonzero.  It is allowed to block, e.g. for user memory
+ * access.  The arch can have machine-specific work to be done before
+ * ptrace stops.  On ia64, register backing store gets written back to user
+ * memory here.  Since this can be costly (requires dropping the siglock),
+ * we only do it when the arch requires it for this particular stop, as
+ * indicated by arch_ptrace_stop_needed().
+ */
+#define arch_ptrace_stop(code, info)            do { } while (0)
+#endif
+
 #endif
 
 #endif