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author | Jason Baron <jbaron@redhat.com> | 2008-08-12 16:46:19 -0400 |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-10-16 09:24:47 -0700 |
commit | 346e15beb5343c2eb8216d820f2ed8f150822b08 (patch) | |
tree | 6433cf2980bbfbed4a9482c5edb156fc8371e071 /scripts/basic | |
parent | 33376c1c043c05077b4ac79c33804266f6c45e49 (diff) | |
download | linux-346e15beb5343c2eb8216d820f2ed8f150822b08.tar.gz |
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 'scripts/basic')
-rw-r--r-- | scripts/basic/Makefile | 2 | ||||
-rw-r--r-- | scripts/basic/hash.c | 64 |
2 files changed, 65 insertions, 1 deletions
diff --git a/scripts/basic/Makefile b/scripts/basic/Makefile index 4c324a1f1e0e..09559951df12 100644 --- a/scripts/basic/Makefile +++ b/scripts/basic/Makefile @@ -9,7 +9,7 @@ # fixdep: Used to generate dependency information during build process # docproc: Used in Documentation/DocBook -hostprogs-y := fixdep docproc +hostprogs-y := fixdep docproc hash always := $(hostprogs-y) # fixdep is needed to compile other host programs diff --git a/scripts/basic/hash.c b/scripts/basic/hash.c new file mode 100644 index 000000000000..3299ad7fc8c0 --- /dev/null +++ b/scripts/basic/hash.c @@ -0,0 +1,64 @@ +/* + * Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com> + * + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#define DYNAMIC_DEBUG_HASH_BITS 6 + +static const char *program; + +static void usage(void) +{ + printf("Usage: %s <djb2|r5> <modname>\n", program); + exit(1); +} + +/* djb2 hashing algorithm by Dan Bernstein. From: + * http://www.cse.yorku.ca/~oz/hash.html + */ + +unsigned int djb2_hash(char *str) +{ + unsigned long hash = 5381; + int c; + + c = *str; + while (c) { + hash = ((hash << 5) + hash) + c; + c = *++str; + } + return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1)); +} + +unsigned int r5_hash(char *str) +{ + unsigned long hash = 0; + int c; + + c = *str; + while (c) { + hash = (hash + (c << 4) + (c >> 4)) * 11; + c = *++str; + } + return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1)); +} + +int main(int argc, char *argv[]) +{ + program = argv[0]; + + if (argc != 3) + usage(); + if (!strcmp(argv[1], "djb2")) + printf("%d\n", djb2_hash(argv[2])); + else if (!strcmp(argv[1], "r5")) + printf("%d\n", r5_hash(argv[2])); + else + usage(); + exit(0); +} + |