diff options
author | Jason Baron <jbaron@redhat.com> | 2008-08-12 20:46:19 (GMT) |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-10-16 16:24:47 (GMT) |
commit | 346e15beb5343c2eb8216d820f2ed8f150822b08 (patch) | |
tree | 6433cf2980bbfbed4a9482c5edb156fc8371e071 /kernel | |
parent | 33376c1c043c05077b4ac79c33804266f6c45e49 (diff) | |
download | linux-346e15beb5343c2eb8216d820f2ed8f150822b08.tar.xz |
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 'kernel')
-rw-r--r-- | kernel/module.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/kernel/module.c b/kernel/module.c index d5fcd24..c527006 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -784,6 +784,7 @@ sys_delete_module(const char __user *name_user, unsigned int flags) mutex_lock(&module_mutex); /* Store the name of the last unloaded module for diagnostic purposes */ strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module)); + unregister_dynamic_debug_module(mod->name); free_module(mod); out: @@ -1783,6 +1784,33 @@ static inline void add_kallsyms(struct module *mod, } #endif /* CONFIG_KALLSYMS */ +#ifdef CONFIG_DYNAMIC_PRINTK_DEBUG +static void dynamic_printk_setup(Elf_Shdr *sechdrs, unsigned int verboseindex) +{ + struct mod_debug *debug_info; + unsigned long pos, end; + unsigned int num_verbose; + + pos = sechdrs[verboseindex].sh_addr; + num_verbose = sechdrs[verboseindex].sh_size / + sizeof(struct mod_debug); + end = pos + (num_verbose * sizeof(struct mod_debug)); + + for (; pos < end; pos += sizeof(struct mod_debug)) { + debug_info = (struct mod_debug *)pos; + register_dynamic_debug_module(debug_info->modname, + debug_info->type, debug_info->logical_modname, + debug_info->flag_names, debug_info->hash, + debug_info->hash2); + } +} +#else +static inline void dynamic_printk_setup(Elf_Shdr *sechdrs, + unsigned int verboseindex) +{ +} +#endif /* CONFIG_DYNAMIC_PRINTK_DEBUG */ + static void *module_alloc_update_bounds(unsigned long size) { void *ret = module_alloc(size); @@ -1831,6 +1859,7 @@ static noinline struct module *load_module(void __user *umod, #endif unsigned int markersindex; unsigned int markersstringsindex; + unsigned int verboseindex; struct module *mod; long err = 0; void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */ @@ -2117,6 +2146,7 @@ static noinline struct module *load_module(void __user *umod, markersindex = find_sec(hdr, sechdrs, secstrings, "__markers"); markersstringsindex = find_sec(hdr, sechdrs, secstrings, "__markers_strings"); + verboseindex = find_sec(hdr, sechdrs, secstrings, "__verbose"); /* Now do relocations. */ for (i = 1; i < hdr->e_shnum; i++) { @@ -2167,6 +2197,7 @@ static noinline struct module *load_module(void __user *umod, marker_update_probe_range(mod->markers, mod->markers + mod->num_markers); #endif + dynamic_printk_setup(sechdrs, verboseindex); err = module_finalize(hdr, sechdrs, mod); if (err < 0) goto cleanup; |