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-rw-r--r--include/linux/dynamic_debug.h88
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..07781aaa1164
--- /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 ":" 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 ": " 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

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