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346e15beb5
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>
94 lines
2.9 KiB
C
94 lines
2.9 KiB
C
#ifndef _DYNAMIC_PRINTK_H
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#define _DYNAMIC_PRINTK_H
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#define DYNAMIC_DEBUG_HASH_BITS 6
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#define DEBUG_HASH_TABLE_SIZE (1 << DYNAMIC_DEBUG_HASH_BITS)
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#define TYPE_BOOLEAN 1
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#define DYNAMIC_ENABLED_ALL 0
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#define DYNAMIC_ENABLED_NONE 1
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#define DYNAMIC_ENABLED_SOME 2
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extern int dynamic_enabled;
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/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
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* bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
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* use independent hash functions, to reduce the chance of false positives.
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*/
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extern long long dynamic_printk_enabled;
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extern long long dynamic_printk_enabled2;
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struct mod_debug {
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char *modname;
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char *logical_modname;
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char *flag_names;
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int type;
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int hash;
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int hash2;
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} __attribute__((aligned(8)));
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int register_dynamic_debug_module(char *mod_name, int type, char *share_name,
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char *flags, int hash, int hash2);
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#if defined(CONFIG_DYNAMIC_PRINTK_DEBUG)
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extern int unregister_dynamic_debug_module(char *mod_name);
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extern int __dynamic_dbg_enabled_helper(char *modname, int type,
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int value, int hash);
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#define __dynamic_dbg_enabled(module, type, value, level, hash) ({ \
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int __ret = 0; \
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if (unlikely((dynamic_printk_enabled & (1LL << DEBUG_HASH)) && \
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(dynamic_printk_enabled2 & (1LL << DEBUG_HASH2)))) \
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__ret = __dynamic_dbg_enabled_helper(module, type, \
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value, hash);\
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__ret; })
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#define dynamic_pr_debug(fmt, ...) do { \
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static char mod_name[] \
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__attribute__((section("__verbose_strings"))) \
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= KBUILD_MODNAME; \
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static struct mod_debug descriptor \
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__used \
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__attribute__((section("__verbose"), aligned(8))) = \
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{ mod_name, mod_name, NULL, TYPE_BOOLEAN, DEBUG_HASH, DEBUG_HASH2 };\
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if (__dynamic_dbg_enabled(KBUILD_MODNAME, TYPE_BOOLEAN, \
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0, 0, DEBUG_HASH)) \
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printk(KERN_DEBUG KBUILD_MODNAME ":" fmt, \
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##__VA_ARGS__); \
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} while (0)
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#define dynamic_dev_dbg(dev, format, ...) do { \
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static char mod_name[] \
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__attribute__((section("__verbose_strings"))) \
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= KBUILD_MODNAME; \
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static struct mod_debug descriptor \
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__used \
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__attribute__((section("__verbose"), aligned(8))) = \
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{ mod_name, mod_name, NULL, TYPE_BOOLEAN, DEBUG_HASH, DEBUG_HASH2 };\
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if (__dynamic_dbg_enabled(KBUILD_MODNAME, TYPE_BOOLEAN, \
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0, 0, DEBUG_HASH)) \
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dev_printk(KERN_DEBUG, dev, \
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KBUILD_MODNAME ": " format, \
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##__VA_ARGS__); \
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} while (0)
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#else
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static inline int unregister_dynamic_debug_module(const char *mod_name)
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{
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return 0;
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}
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static inline int __dynamic_dbg_enabled_helper(char *modname, int type,
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int value, int hash)
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{
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return 0;
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}
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#define __dynamic_dbg_enabled(module, type, value, level, hash) ({ 0; })
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#define dynamic_pr_debug(fmt, ...) do { } while (0)
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#define dynamic_dev_dbg(dev, format, ...) do { } while (0)
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#endif
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#endif
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