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authorJason Baron <jbaron@redhat.com>2008-08-12 16:46:19 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2008-10-16 09:24:47 -0700
commit346e15beb5343c2eb8216d820f2ed8f150822b08 (patch)
tree6433cf2980bbfbed4a9482c5edb156fc8371e071 /include/linux/dynamic_printk.h
parent33376c1c043c05077b4ac79c33804266f6c45e49 (diff)
driver core: basic infrastructure for per-module dynamic debug messages
Base infrastructure to enable per-module debug messages. I've introduced CONFIG_DYNAMIC_PRINTK_DEBUG, which when enabled centralizes control of debugging statements on a per-module basis in one /proc file, currently, <debugfs>/dynamic_printk/modules. When, CONFIG_DYNAMIC_PRINTK_DEBUG, is not set, debugging statements can still be enabled as before, often by defining 'DEBUG' for the proper compilation unit. Thus, this patch set has no affect when CONFIG_DYNAMIC_PRINTK_DEBUG is not set. The infrastructure currently ties into all pr_debug() and dev_dbg() calls. That is, if CONFIG_DYNAMIC_PRINTK_DEBUG is set, all pr_debug() and dev_dbg() calls can be dynamically enabled/disabled on a per-module basis. Future plans include extending this functionality to subsystems, that define their own debug levels and flags. Usage: Dynamic debugging is controlled by the debugfs file, <debugfs>/dynamic_printk/modules. This file contains a list of the modules that can be enabled. The format of the file is as follows: <module_name> <enabled=0/1> . . . <module_name> : Name of the module in which the debug call resides <enabled=0/1> : whether the messages are enabled or not For example: snd_hda_intel enabled=0 fixup enabled=1 driver enabled=0 Enable a module: $echo "set enabled=1 <module_name>" > dynamic_printk/modules Disable a module: $echo "set enabled=0 <module_name>" > dynamic_printk/modules Enable all modules: $echo "set enabled=1 all" > dynamic_printk/modules Disable all modules: $echo "set enabled=0 all" > dynamic_printk/modules Finally, passing "dynamic_printk" at the command line enables debugging for all modules. This mode can be turned off via the above disable command. [gkh: minor cleanups and tweaks to make the build work quietly] Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'include/linux/dynamic_printk.h')
-rw-r--r--include/linux/dynamic_printk.h93
1 files changed, 93 insertions, 0 deletions
diff --git a/include/linux/dynamic_printk.h b/include/linux/dynamic_printk.h
new file mode 100644
index 00000000000..2d528d00907
--- /dev/null
+++ b/include/linux/dynamic_printk.h
@@ -0,0 +1,93 @@
+#ifndef _DYNAMIC_PRINTK_H
+#define _DYNAMIC_PRINTK_H
+
+#define DYNAMIC_DEBUG_HASH_BITS 6
+#define DEBUG_HASH_TABLE_SIZE (1 << DYNAMIC_DEBUG_HASH_BITS)
+
+#define TYPE_BOOLEAN 1
+
+#define DYNAMIC_ENABLED_ALL 0
+#define DYNAMIC_ENABLED_NONE 1
+#define DYNAMIC_ENABLED_SOME 2
+
+extern int dynamic_enabled;
+
+/* 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_printk_enabled;
+extern long long dynamic_printk_enabled2;
+
+struct mod_debug {
+ char *modname;
+ char *logical_modname;
+ char *flag_names;
+ int type;
+ int hash;
+ int hash2;
+} __attribute__((aligned(8)));
+
+int register_dynamic_debug_module(char *mod_name, int type, char *share_name,
+ char *flags, int hash, int hash2);
+
+#if defined(CONFIG_DYNAMIC_PRINTK_DEBUG)
+extern int unregister_dynamic_debug_module(char *mod_name);
+extern int __dynamic_dbg_enabled_helper(char *modname, int type,
+ int value, int hash);
+
+#define __dynamic_dbg_enabled(module, type, value, level, hash) ({ \
+ int __ret = 0; \
+ if (unlikely((dynamic_printk_enabled & (1LL << DEBUG_HASH)) && \
+ (dynamic_printk_enabled2 & (1LL << DEBUG_HASH2)))) \
+ __ret = __dynamic_dbg_enabled_helper(module, type, \
+ value, hash);\
+ __ret; })
+
+#define dynamic_pr_debug(fmt, ...) do { \
+ static char mod_name[] \
+ __attribute__((section("__verbose_strings"))) \
+ = KBUILD_MODNAME; \
+ static struct mod_debug descriptor \
+ __used \
+ __attribute__((section("__verbose"), aligned(8))) = \
+ { mod_name, mod_name, NULL, TYPE_BOOLEAN, DEBUG_HASH, DEBUG_HASH2 };\
+ if (__dynamic_dbg_enabled(KBUILD_MODNAME, TYPE_BOOLEAN, \
+ 0, 0, DEBUG_HASH)) \
+ printk(KERN_DEBUG KBUILD_MODNAME ":" fmt, \
+ ##__VA_ARGS__); \
+ } while (0)
+
+#define dynamic_dev_dbg(dev, format, ...) do { \
+ static char mod_name[] \
+ __attribute__((section("__verbose_strings"))) \
+ = KBUILD_MODNAME; \
+ static struct mod_debug descriptor \
+ __used \
+ __attribute__((section("__verbose"), aligned(8))) = \
+ { mod_name, mod_name, NULL, TYPE_BOOLEAN, DEBUG_HASH, DEBUG_HASH2 };\
+ if (__dynamic_dbg_enabled(KBUILD_MODNAME, TYPE_BOOLEAN, \
+ 0, 0, DEBUG_HASH)) \
+ dev_printk(KERN_DEBUG, dev, \
+ KBUILD_MODNAME ": " format, \
+ ##__VA_ARGS__); \
+ } while (0)
+
+#else
+
+static inline int unregister_dynamic_debug_module(const char *mod_name)
+{
+ return 0;
+}
+static inline int __dynamic_dbg_enabled_helper(char *modname, int type,
+ int value, int hash)
+{
+ return 0;
+}
+
+#define __dynamic_dbg_enabled(module, type, value, level, hash) ({ 0; })
+#define dynamic_pr_debug(fmt, ...) do { } while (0)
+#define dynamic_dev_dbg(dev, format, ...) do { } while (0)
+#endif
+
+#endif