+#ifdef CONFIG_TRACING
+extern void tracing_start(void);
+extern void tracing_stop(void);
+extern void ftrace_off_permanent(void);
+
+extern void
+ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
+
+static inline void __attribute__ ((format (printf, 1, 2)))
+____trace_printk_check_format(const char *fmt, ...)
+{
+}
+#define __trace_printk_check_format(fmt, args...) \
+do { \
+ if (0) \
+ ____trace_printk_check_format(fmt, ##args); \
+} while (0)
+
+/**
+ * trace_printk - printf formatting in the ftrace buffer
+ * @fmt: the printf format for printing
+ *
+ * Note: __trace_printk is an internal function for trace_printk and
+ * the @ip is passed in via the trace_printk macro.
+ *
+ * This function allows a kernel developer to debug fast path sections
+ * that printk is not appropriate for. By scattering in various
+ * printk like tracing in the code, a developer can quickly see
+ * where problems are occurring.
+ *
+ * This is intended as a debugging tool for the developer only.
+ * Please refrain from leaving trace_printks scattered around in
+ * your code.
+ */
+
+#define trace_printk(fmt, args...) \
+do { \
+ __trace_printk_check_format(fmt, ##args); \
+ if (__builtin_constant_p(fmt)) { \
+ static const char *trace_printk_fmt \
+ __attribute__((section("__trace_printk_fmt"))) = \
+ __builtin_constant_p(fmt) ? fmt : NULL; \
+ \
+ __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
+ } else \
+ __trace_printk(_THIS_IP_, fmt, ##args); \
+} while (0)
+
+extern int
+__trace_bprintk(unsigned long ip, const char *fmt, ...)
+ __attribute__ ((format (printf, 2, 3)));
+
+extern int
+__trace_printk(unsigned long ip, const char *fmt, ...)
+ __attribute__ ((format (printf, 2, 3)));
+
+/*
+ * The double __builtin_constant_p is because gcc will give us an error
+ * if we try to allocate the static variable to fmt if it is not a
+ * constant. Even with the outer if statement.
+ */
+#define ftrace_vprintk(fmt, vargs) \
+do { \
+ if (__builtin_constant_p(fmt)) { \
+ static const char *trace_printk_fmt \
+ __attribute__((section("__trace_printk_fmt"))) = \
+ __builtin_constant_p(fmt) ? fmt : NULL; \
+ \
+ __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
+ } else \
+ __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
+} while (0)
+
+extern int
+__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
+
+extern int
+__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
+
+extern void ftrace_dump(void);
+#else
+static inline void
+ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
+static inline int
+trace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
+
+static inline void tracing_start(void) { }
+static inline void tracing_stop(void) { }
+static inline void ftrace_off_permanent(void) { }
+static inline int
+trace_printk(const char *fmt, ...)
+{
+ return 0;
+}
+static inline int
+ftrace_vprintk(const char *fmt, va_list ap)
+{
+ return 0;
+}
+static inline void ftrace_dump(void) { }
+#endif /* CONFIG_TRACING */