From 346e15beb5343c2eb8216d820f2ed8f150822b08 Mon Sep 17 00:00:00 2001 From: Jason Baron Date: Tue, 12 Aug 2008 16:46:19 -0400 Subject: 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, /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, /dynamic_printk/modules. This file contains a list of the modules that can be enabled. The format of the file is as follows: . . . : Name of the module in which the debug call resides : 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 " > dynamic_printk/modules Disable a module: $echo "set enabled=0 " > 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 Signed-off-by: Greg Kroah-Hartman --- include/linux/dynamic_printk.h | 93 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 include/linux/dynamic_printk.h (limited to 'include/linux/dynamic_printk.h') 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 -- cgit v1.2.3