1 files changed, 88 insertions, 0 deletions
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
new file mode 100644
index 000000000000..baabf33be244
--- /dev/null
+++ b/include/linux/dynamic_debug.h
@@ -0,0 +1,88 @@
+#ifndef _DYNAMIC_DEBUG_H
+#define _DYNAMIC_DEBUG_H
+
+/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
+ * bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
+ * use independent hash functions, to reduce the chance of false positives.
+ */
+extern long long dynamic_debug_enabled;
+extern long long dynamic_debug_enabled2;
+
+/*
+ * An instance of this structure is created in a special
+ * ELF section at every dynamic debug callsite.  At runtime,
+ * the special section is treated as an array of these.
+ */
+struct _ddebug {
+	/*
+	 * These fields are used to drive the user interface
+	 * for selecting and displaying debug callsites.
+	 */
+	const char *modname;
+	const char *function;
+	const char *filename;
+	const char *format;
+	char primary_hash;
+	char secondary_hash;
+	unsigned int lineno:24;
+	/*
+ 	 * The flags field controls the behaviour at the callsite.
+ 	 * The bits here are changed dynamically when the user
+ 	 * writes commands to <debugfs>/dynamic_debug/ddebug
+	 */
+#define _DPRINTK_FLAGS_PRINT   (1<<0)  /* printk() a message using the format */
+#define _DPRINTK_FLAGS_DEFAULT 0
+	unsigned int flags:8;
+} __attribute__((aligned(8)));
+
+
+int ddebug_add_module(struct _ddebug *tab, unsigned int n,
+				const char *modname);
+
+#if defined(CONFIG_DYNAMIC_DEBUG)
+extern int ddebug_remove_module(char *mod_name);
+
+#define __dynamic_dbg_enabled(dd)  ({	     \
+	int __ret = 0;							     \
+	if (unlikely((dynamic_debug_enabled & (1LL << DEBUG_HASH)) &&	     \
+			(dynamic_debug_enabled2 & (1LL << DEBUG_HASH2))))   \
+				if (unlikely(dd.flags))			     \
+					__ret = 1;			     \
+	__ret; })
+
+#define dynamic_pr_debug(fmt, ...) do {					\
+	static struct _ddebug descriptor				\
+	__used								\
+	__attribute__((section("__verbose"), aligned(8))) =		\
+	{ KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH,	\
+		DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT };	\
+	if (__dynamic_dbg_enabled(descriptor))				\
+		printk(KERN_DEBUG KBUILD_MODNAME ":" pr_fmt(fmt),	\
+				##__VA_ARGS__);				\
+	} while (0)
+
+
+#define dynamic_dev_dbg(dev, fmt, ...) do {				\
+	static struct _ddebug descriptor				\
+	__used								\
+	__attribute__((section("__verbose"), aligned(8))) =		\
+	{ KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH,	\
+		DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT };	\
+	if (__dynamic_dbg_enabled(descriptor))				\
+			dev_printk(KERN_DEBUG, dev,			\
+					KBUILD_MODNAME ": " pr_fmt(fmt),\
+					##__VA_ARGS__);			\
+	} while (0)
+
+#else
+
+static inline int ddebug_remove_module(char *mod)
+{
+	return 0;
+}
+
+#define dynamic_pr_debug(fmt, ...)  do { } while (0)
+#define dynamic_dev_dbg(dev, format, ...)  do { } while (0)
+#endif
+
+#endif