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]
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| @@ -9,7 +9,7 @@ · 8 unmodified lines | |||
| 9 | # fixdep: Used to generate dependency information during build process | 9 | # fixdep: Used to generate dependency information during build process |
| 10 | # docproc: Used in Documentation/DocBook | 10 | # docproc: Used in Documentation/DocBook |
| 11 | 11 | ||
| 12 | hostprogs-y := fixdep docproc | 12 | hostprogs-y := fixdep docproc hash |
| 13 | always := $(hostprogs-y) | 13 | always := $(hostprogs-y) |
| 14 | 14 | ||
| 15 | # fixdep is needed to compile other host programs | 15 | # fixdep is needed to compile other host programs |
| @@ -0,0 +1,64 @@ | |||
| 1 | /* | ||
| 2 | * Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com> | ||
| 3 | * | ||
| 4 | */ | ||
| 5 | |||
| 6 | #include <stdio.h> | ||
| 7 | #include <stdlib.h> | ||
| 8 | #include <string.h> | ||
| 9 | |||
| 10 | #define DYNAMIC_DEBUG_HASH_BITS 6 | ||
| 11 | |||
| 12 | static const char *program; | ||
| 13 | |||
| 14 | static void usage(void) | ||
| 15 | { | ||
| 16 | printf("Usage: %s <djb2|r5> <modname>\n", program); | ||
| 17 | exit(1); | ||
| 18 | } | ||
| 19 | |||
| 20 | /* djb2 hashing algorithm by Dan Bernstein. From: | ||
| 21 | * http://www.cse.yorku.ca/~oz/hash.html | ||
| 22 | */ | ||
| 23 | |||
| 24 | unsigned int djb2_hash(char *str) | ||
| 25 | { | ||
| 26 | unsigned long hash = 5381; | ||
| 27 | int c; | ||
| 28 | |||
| 29 | c = *str; | ||
| 30 | while (c) { | ||
| 31 | hash = ((hash << 5) + hash) + c; | ||
| 32 | c = *++str; | ||
| 33 | } | ||
| 34 | return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1)); | ||
| 35 | } | ||
| 36 | |||
| 37 | unsigned int r5_hash(char *str) | ||
| 38 | { | ||
| 39 | unsigned long hash = 0; | ||
| 40 | int c; | ||
| 41 | |||
| 42 | c = *str; | ||
| 43 | while (c) { | ||
| 44 | hash = (hash + (c << 4) + (c >> 4)) * 11; | ||
| 45 | c = *++str; | ||
| 46 | } | ||
| 47 | return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1)); | ||
| 48 | } | ||
| 49 | |||
| 50 | int main(int argc, char *argv[]) | ||
| 51 | { | ||
| 52 | program = argv[0]; | ||
| 53 | |||
| 54 | if (argc != 3) | ||
| 55 | usage(); | ||
| 56 | if (!strcmp(argv[1], "djb2")) | ||
| 57 | printf("%d\n", djb2_hash(argv[2])); | ||
| 58 | else if (!strcmp(argv[1], "r5")) | ||
| 59 | printf("%d\n", r5_hash(argv[2])); | ||
| 60 | else | ||
| 61 | usage(); | ||
| 62 | exit(0); | ||
| 63 | } | ||
| 64 | |||