1 files changed, 27 insertions, 13 deletions

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 7742798c9208..1daca3b062bb 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -452,32 +452,46 @@ do {									\
 
 #define trace_printk(fmt, args...)                                      \
 do {                                                                    \
-        static const char *trace_printk_fmt                             \
-        __attribute__((section("__trace_printk_fmt")));                 \
-                                                                        \
-        if (!trace_printk_fmt)                                          \
-                trace_printk_fmt = fmt;                                 \
-                                                                        \
         __trace_printk_check_format(fmt, ##args);                       \
-        __trace_printk(_THIS_IP_, trace_printk_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 {                                                                    \
-        static const char *trace_printk_fmt                             \
-        __attribute__((section("__trace_printk_fmt")));                 \
-                                                                        \
-        if (!trace_printk_fmt)                                          \
-                trace_printk_fmt = fmt;                                 \
+        if (__builtin_constant_p(fmt)) {                                \
+                static const char *trace_printk_fmt                     \
+                  __attribute__((section("__trace_printk_fmt"))) =      \
+                        __builtin_constant_p(fmt) ? fmt : NULL;         \
                                                                         \
-        __ftrace_vprintk(_THIS_IP_, trace_printk_fmt, vargs);           \
+                __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);