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authorJason Baron <jbaron@redhat.com>2008-08-12 22:46:19 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2008-10-16 18:24:47 +0200
commit346e15beb5343c2eb8216d820f2ed8f150822b08 (patch)
tree6433cf2980bbfbed4a9482c5edb156fc8371e071 /kernel/module.c
parentusb gadget: link fixes for network gadget (diff)
downloadlinux-346e15beb5343c2eb8216d820f2ed8f150822b08.tar.xz
linux-346e15beb5343c2eb8216d820f2ed8f150822b08.zip
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/module.c')
-rw-r--r--kernel/module.c31
1 files changed, 31 insertions, 0 deletions
diff --git a/kernel/module.c b/kernel/module.c
index d5fcd24e5aff..c52700667292 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;