1 files changed, 59 insertions, 2 deletions

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 98115d9d04da..935e30cfaf3c 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -59,8 +59,65 @@ extern void __chk_io_ptr(const volatile void __iomem *);
  * specific implementations come from the above header files
  */
 
-#define likely(x)       __builtin_expect(!!(x), 1)
-#define unlikely(x)     __builtin_expect(!!(x), 0)
+#ifdef CONFIG_TRACE_UNLIKELY_PROFILE
+struct ftrace_likely_data {
+        const char *func;
+        const char *file;
+        unsigned line;
+        unsigned long correct;
+        unsigned long incorrect;
+};
+void ftrace_likely_update(struct ftrace_likely_data *f, int val, int expect);
+
+#define likely_notrace(x)       __builtin_expect(!!(x), 1)
+#define unlikely_notrace(x)     __builtin_expect(!!(x), 0)
+
+#define likely_check(x) ({                                              \
+                        int ______r;                                    \
+                        static struct ftrace_likely_data                \
+                                __attribute__((__aligned__(4)))         \
+                                __attribute__((section("_ftrace_likely"))) \
+                                ______f = {                             \
+                                .func = __func__,                       \
+                                .file = __FILE__,                       \
+                                .line = __LINE__,                       \
+                        };                                              \
+                        ______f.line = __LINE__;                        \
+                        ______r = likely_notrace(x);                    \
+                        ftrace_likely_update(&______f, ______r, 1);     \
+                        ______r;                                        \
+                })
+#define unlikely_check(x) ({                                            \
+                        int ______r;                                    \
+                        static struct ftrace_likely_data                \
+                                __attribute__((__aligned__(4)))         \
+                                __attribute__((section("_ftrace_unlikely"))) \
+                                ______f = {                             \
+                                .func = __func__,                       \
+                                .file = __FILE__,                       \
+                                .line = __LINE__,                       \
+                        };                                              \
+                        ______f.line = __LINE__;                        \
+                        ______r = unlikely_notrace(x);                  \
+                        ftrace_likely_update(&______f, ______r, 0);     \
+                        ______r;                                        \
+                })
+
+/*
+ * Using __builtin_constant_p(x) to ignore cases where the return
+ * value is always the same.  This idea is taken from a similar patch
+ * written by Daniel Walker.
+ */
+# ifndef likely
+#  define likely(x)     (__builtin_constant_p(x) ? !!(x) : likely_check(x))
+# endif
+# ifndef unlikely
+#  define unlikely(x)   (__builtin_constant_p(x) ? !!(x) : unlikely_check(x))
+# endif
+#else
+# define likely(x)      __builtin_expect(!!(x), 1)
+# define unlikely(x)    __builtin_expect(!!(x), 0)
+#endif
 
 /* Optimization barrier */
 #ifndef barrier