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