[00/11] pr_debug during module initialization

[00/11] pr_debug during module initialization

[jim.cromie]

This is 3rd revision of the dyndbg modinit patches, previously sent
Dec 11.  Patches 1-17/25 sent then were added to driver-core-next,
this set reworks the remainder.

It implements the "fake" module param approach proposed by
Thomas Renninger, back in https://lkml.org/lkml/2010/9/15/397

This set is on top of linux-next, since that includes Pawel Moll's
initcall-level params patch.  Im not using this feature, but I didnt
know that when I started.

Rusty Russell did a partial review of 2nd rev (sent off-list), here:
http://thread.gmane.org/gmane.linux.kernel/1262934
This revision incorporates my understanding of his feedback.

Core of patchset is 2 callbacks, called from parse_args:

For builtin modules, dynamic_debug_init() calls parse_args(...,
&ddebug_dyndbg_boot_param_cb) to handle dyndbg and $module.dyndbg
params.  For loadable modules, load_module() calls parse_args(...,
&ddebug_dyndbg_module_param_cb) to handle dyndbg args given by
modprobe.  Both callbacks call ddebug_exec_queries() to activate the
specified pr_debug callsites.

0001-init-trivial-tweaks-to-initcall_levels.patch
This adds pr_info for each initcall-level, yielding 7 lines in dmesg
like:
  initlevel:6=device, 172 registered initcalls

I dropped the pr_debug added in 2nd rev, which was noisy and not
useful, init_debug provides similar info and more.  This patch is
decoration only, and can be dropped.

0002-dynamic_debug-fix-leading-spaces.patch
whitespace

0003-dynamic_debug-replace-if-verbose-pr_info-with-macro-.patch
I should have done this previously.  Ive disregarded a complaint about
wrapping complex macro args in (), since theres plenty of similar code
in include/*

0004-dynamic_debug-change-ddebug_query-core-param-to-dynd.patch
Change "ddebug_query" to "dyndbg", to match new $module.dyndbg added
by this patchset.

0005-params-add-param-name-to-parse_one-s-pr_debug.patch
Current message doesnt ID the param name being handled.

0006-params-add-3rd-arg-to-option-handler-callback-signat.patch
Add "doing" to lower levels of param handling callchain, supplying it
to callback added next.

0007-dynamic_debug-make-dynamic-debug-work-during-module-.patch
main patch of set.

0008-pnp-if-CONFIG_DYNAMIC_DEBUG-use-pnp.dyndbg-instead-o.patch
Adjust pnp for CONFIG_PNP_DEBUG_MESSAGES.  Unchanged since Dec 11th

0009-dynamic_debug-add-modname-arg-to-exec_query-callchai.patch
This allows parsing $modname.dyndbg=" func foo +p ; func bar +p"
without repeating "module $modname" 2x in the value

0010-dynamic_debug-update-Documentation-Kconfig.debug.patch
This gets a checkpatch complaint because of long lines in which I
tweaked flags.  I chose to disregard this cuz the lines show real
output for ~out-of-tree code.

0011-dynamic_debug-init-with-core_initcall-not-arch_initc.patch
This works-for-me, but may be broken on some arches I dont have to
test on.  I dont know why original design used arch_initcall, perhaps
constraints have changed.  I also tested with early_initcall, that
also worked.

[PATCH 01/11] init: trivial tweaks to initcall_levels

[jim.cromie]

From: Jim Cromie <jim.cromie@gmail.com>

add a pr_info to print current level and level_name of initcall,
and number of registered initcalls at that level.  This adds 7
lines to dmesg output, like:
   initlevel:6=device, 172 registered initcalls

Drop "parameters" from initcall_level_names[], it can be added
back in the printk where it clarifies things.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 init/main.c |   25 +++++++++++++++----------
 1 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/init/main.c b/init/main.c
index d595751..deee88f 100644
--- a/init/main.c
+++ b/init/main.c
@@ -723,14 +723,14 @@ static initcall_t *initcall_levels[] __initdata = {
 };
 
 static char *initcall_level_names[] __initdata = {
-	"early parameters",
-	"core parameters",
-	"postcore parameters",
-	"arch parameters",
-	"subsys parameters",
-	"fs parameters",
-	"device parameters",
-	"late parameters",
+	"early",
+	"core",
+	"postcore",
+	"arch",
+	"subsys",
+	"fs",
+	"device",
+	"late",
 };
 
 static int __init ignore_unknown_bootoption(char *param, char *val)
@@ -748,7 +748,7 @@ static void __init do_initcall_level(int level)
 		   static_command_line, __start___param,
 		   __stop___param - __start___param,
 		   level, level,
-		   ignore_unknown_bootoption);
+		   &ignore_unknown_bootoption);
 
 	for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
 		do_one_initcall(*fn);
@@ -758,8 +758,13 @@ static void __init do_initcalls(void)
 {
 	int level;
 
-	for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
+	for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) {
+		pr_info("initlevel:%d=%s, %d registered initcalls\n",
+			level, initcall_level_names[level],
+			(int) (initcall_levels[level+1]
+				- initcall_levels[level]));
 		do_initcall_level(level);
+	}
 }
 
 /*
-- 
1.7.7.6

[PATCH 02/11] dynamic_debug: fix leading spaces

[jim.cromie]

From: Jim Cromie <jim.cromie@gmail.com>

clean up some space-before-tabs problems.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 7e3c53a..bf1b0fc 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -17,8 +17,8 @@ struct _ddebug {
 	const char *format;
 	unsigned int lineno:18;
 	/*
- 	 * The flags field controls the behaviour at the callsite.
- 	 * The bits here are changed dynamically when the user
+	 * The flags field controls the behaviour at the callsite.
+	 * The bits here are changed dynamically when the user
 	 * writes commands to <debugfs>/dynamic_debug/control
 	 */
 #define _DPRINTK_FLAGS_NONE	0
-- 
1.7.7.6

[PATCH 03/11] dynamic_debug: replace if (verbose) pr_info with macro vpr_info

[jim.cromie]

From: Jim Cromie <jim.cromie@gmail.com>

use new macro to declutter code, reduce indenting.
dont use pr_debug in lib/dynamic_debug.c, replace with vpr_info.
Disregard checkpatch warning about complex macro arg; there are
plenty of examples in include/*

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c |   79 ++++++++++++++++++++++-----------------------------
 1 files changed, 34 insertions(+), 45 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 310c753..563e5fc 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -107,20 +107,22 @@ static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
 	return buf;
 }
 
-#define vpr_info_dq(q, msg)						\
-do {									\
-	if (verbose)							\
-		/* trim last char off format print */			\
-		pr_info("%s: func=\"%s\" file=\"%s\" "			\
-			"module=\"%s\" format=\"%.*s\" "		\
-			"lineno=%u-%u",					\
-			msg,						\
-			q->function ? q->function : "",			\
-			q->filename ? q->filename : "",			\
-			q->module ? q->module : "",			\
-			(int)(q->format ? strlen(q->format) - 1 : 0),	\
-			q->format ? q->format : "",			\
-			q->first_lineno, q->last_lineno);		\
+#define vpr_info(fmt, ...) \
+	if (verbose) do { pr_info(fmt, ##__VA_ARGS__); } while (0)
+
+#define vpr_info_dq(q, msg)					\
+do {								\
+	/* trim last char off format print */			\
+	vpr_info("%s: func=\"%s\" file=\"%s\" "			\
+		"module=\"%s\" format=\"%.*s\" "		\
+		"lineno=%u-%u",					\
+		msg,						\
+		q->function ? q->function : "",			\
+		q->filename ? q->filename : "",			\
+		q->module ? q->module : "",			\
+		(int)(q->format ? strlen(q->format) - 1 : 0),	\
+		q->format ? q->format : "",			\
+		q->first_lineno, q->last_lineno);		\
 } while (0)
 
 /*
@@ -180,12 +182,11 @@ static int ddebug_change(const struct ddebug_query *query,
 			if (newflags == dp->flags)
 				continue;
 			dp->flags = newflags;
-			if (verbose)
-				pr_info("changed %s:%d [%s]%s =%s\n",
-					trim_prefix(dp->filename), dp->lineno,
-					dt->mod_name, dp->function,
-					ddebug_describe_flags(dp, flagbuf,
-							sizeof(flagbuf)));
+			vpr_info("changed %s:%d [%s]%s =%s\n",
+				trim_prefix(dp->filename), dp->lineno,
+				dt->mod_name, dp->function,
+				ddebug_describe_flags(dp, flagbuf,
+						sizeof(flagbuf)));
 		}
 	}
 	mutex_unlock(&ddebug_lock);
@@ -410,8 +411,7 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
 	default:
 		return -EINVAL;
 	}
-	if (verbose)
-		pr_info("op='%c'\n", op);
+	vpr_info("op='%c'\n", op);
 
 	for ( ; *str ; ++str) {
 		for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
@@ -423,8 +423,7 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
 		if (i < 0)
 			return -EINVAL;
 	}
-	if (verbose)
-		pr_info("flags=0x%x\n", flags);
+	vpr_info("flags=0x%x\n", flags);
 
 	/* calculate final *flagsp, *maskp according to mask and op */
 	switch (op) {
@@ -441,8 +440,7 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
 		*flagsp = 0;
 		break;
 	}
-	if (verbose)
-		pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
+	vpr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
 	return 0;
 }
 
@@ -487,8 +485,7 @@ static int ddebug_exec_queries(char *query)
 		if (!query || !*query || *query == '#')
 			continue;
 
-		if (verbose)
-			pr_info("query %d: \"%s\"\n", i, query);
+		vpr_info("query %d: \"%s\"\n", i, query);
 
 		rc = ddebug_exec_query(query);
 		if (rc < 0) {
@@ -653,8 +650,7 @@ static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
 		return -EFAULT;
 	}
 	tmpbuf[len] = '\0';
-	if (verbose)
-		pr_info("read %d bytes from userspace\n", (int)len);
+	vpr_info("read %d bytes from userspace\n", (int)len);
 
 	ret = ddebug_exec_queries(tmpbuf);
 	kfree(tmpbuf);
@@ -717,8 +713,7 @@ static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
 	struct _ddebug *dp;
 	int n = *pos;
 
-	if (verbose)
-		pr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
+	vpr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
 
 	mutex_lock(&ddebug_lock);
 
@@ -742,9 +737,8 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
 	struct ddebug_iter *iter = m->private;
 	struct _ddebug *dp;
 
-	if (verbose)
-		pr_info("called m=%p p=%p *pos=%lld\n",
-			m, p, (unsigned long long)*pos);
+	vpr_info("called m=%p p=%p *pos=%lld\n",
+		m, p, (unsigned long long)*pos);
 
 	if (p == SEQ_START_TOKEN)
 		dp = ddebug_iter_first(iter);
@@ -766,8 +760,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 	struct _ddebug *dp = p;
 	char flagsbuf[10];
 
-	if (verbose)
-		pr_info("called m=%p p=%p\n", m, p);
+	vpr_info("called m=%p p=%p\n", m, p);
 
 	if (p == SEQ_START_TOKEN) {
 		seq_puts(m,
@@ -791,8 +784,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
  */
 static void ddebug_proc_stop(struct seq_file *m, void *p)
 {
-	if (verbose)
-		pr_info("called m=%p p=%p\n", m, p);
+	vpr_info("called m=%p p=%p\n", m, p);
 	mutex_unlock(&ddebug_lock);
 }
 
@@ -815,8 +807,7 @@ static int ddebug_proc_open(struct inode *inode, struct file *file)
 	struct ddebug_iter *iter;
 	int err;
 
-	if (verbose)
-		pr_info("called\n");
+	vpr_info("called\n");
 
 	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 	if (iter == NULL)
@@ -866,8 +857,7 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
 
-	if (verbose)
-		pr_info("%u debug prints in module %s\n", n, dt->mod_name);
+	vpr_info("%u debug prints in module %s\n", n, dt->mod_name);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(ddebug_add_module);
@@ -888,8 +878,7 @@ int ddebug_remove_module(const char *mod_name)
 	struct ddebug_table *dt, *nextdt;
 	int ret = -ENOENT;
 
-	if (verbose)
-		pr_info("removing module \"%s\"\n", mod_name);
+	vpr_info("removing module \"%s\"\n", mod_name);
 
 	mutex_lock(&ddebug_lock);
 	list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
-- 
1.7.7.6

[PATCH 04/11] dynamic_debug: change ddebug_query core param to dyndbg

[jim.cromie]

From: Jim Cromie <jim.cromie@gmail.com>

The "ddebug_query" boot-param allows enabling of pr_debug()s
in built-in modules.  Change it to "dyndbg" to make it
consistent with the $module.dyndbg param added soon.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 563e5fc..1435981 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -623,7 +623,7 @@ static __init int ddebug_setup_query(char *str)
 	return 1;
 }
 
-__setup("ddebug_query=", ddebug_setup_query);
+__setup("dyndbg=", ddebug_setup_query);
 
 /*
  * File_ops->write method for <debugfs>/dynamic_debug/conrol.  Gathers the
-- 
1.7.7.6

[PATCH 05/11] params: add param-name to parse_one's pr_debug()

[jim.cromie]

From: Jim Cromie <jim.cromie@gmail.com>

Current message doesnt identify the param being handled, add it.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 kernel/params.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/params.c b/kernel/params.c
index f37d826..10eb451 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -104,8 +104,8 @@ static int parse_one(char *param,
 			if (!val && params[i].ops->set != param_set_bool
 			    && params[i].ops->set != param_set_bint)
 				return -EINVAL;
-			pr_debug("They are equal!  Calling %p\n",
-			       params[i].ops->set);
+			pr_debug("handling %s with %p\n", param,
+				params[i].ops->set);
 			mutex_lock(&param_lock);
 			err = params[i].ops->set(val, &params[i]);
 			mutex_unlock(&param_lock);
-- 
1.7.7.6

[PATCH 06/11] params: add 3rd arg to option handler callback signature

[jim.cromie]

From: Jim Cromie <jim.cromie@gmail.com>

Add a 3rd arg, named "doing", to unknown_bootoption()
and other option handler callbacks.  The arg is passed as:

  "Booting kernel" from start_kernel(),
  initcall_level_names[i] from do_initcall_level(),
  mod->name from load_module(), via parse_args(), parse_one()

parse_args() already has the "name" parameter, which is also
renamed to "doing" to better reflect current uses 1,2 above.
parse_args() passes it to an altered parse_one(), which passes it
down into the unknown option handler callbacks.

The mod->name is needed for loadable modules, since params passed
there are not qualified (they do not have a "$modname." prefix),
and by the time the unknown-param callback is called, the module
name is not otherwize available.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/moduleparam.h |    3 ++-
 init/main.c                 |    8 +++++---
 kernel/params.c             |   23 +++++++++++++----------
 3 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index ea36486..1b14d25 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -320,7 +320,8 @@ extern int parse_args(const char *name,
 		      unsigned num,
 		      s16 level_min,
 		      s16 level_max,
-		      int (*unknown)(char *param, char *val));
+		      int (*unknown)(char *param, char *val,
+			      const char *doing));
 
 /* Called by module remove. */
 #ifdef CONFIG_SYSFS
diff --git a/init/main.c b/init/main.c
index deee88f..c2cd4d8 100644
--- a/init/main.c
+++ b/init/main.c
@@ -230,7 +230,8 @@ early_param("loglevel", loglevel);
  * Unknown boot options get handed to init, unless they look like
  * unused parameters (modprobe will find them in /proc/cmdline).
  */
-static int __init unknown_bootoption(char *param, char *val)
+static int __init unknown_bootoption(char *param, char *val,
+				const char *unused)
 {
 	/* Change NUL term back to "=", to make "param" the whole string. */
 	if (val) {
@@ -380,7 +381,7 @@ static noinline void __init_refok rest_init(void)
 }
 
 /* Check for early params. */
-static int __init do_early_param(char *param, char *val)
+static int __init do_early_param(char *param, char *val, const char *unused)
 {
 	const struct obs_kernel_param *p;
 
@@ -733,7 +734,8 @@ static char *initcall_level_names[] __initdata = {
 	"late",
 };
 
-static int __init ignore_unknown_bootoption(char *param, char *val)
+static int __init ignore_unknown_bootoption(char *param, char *val,
+					const char *doing)
 {
 	return 0;
 }
diff --git a/kernel/params.c b/kernel/params.c
index 10eb451..7f127ac 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -85,11 +85,13 @@ bool parameq(const char *a, const char *b)
 
 static int parse_one(char *param,
 		     char *val,
+		     const char *doing,
 		     const struct kernel_param *params,
 		     unsigned num_params,
 		     s16 min_level,
 		     s16 max_level,
-		     int (*handle_unknown)(char *param, char *val))
+		     int (*handle_unknown)(char *param, char *val,
+				     const char *doing))
 {
 	unsigned int i;
 	int err;
@@ -114,8 +116,9 @@ static int parse_one(char *param,
 	}
 
 	if (handle_unknown) {
-		pr_debug("Unknown argument: calling %p\n", handle_unknown);
-		return handle_unknown(param, val);
+		/* Booting kernel, early options are too early for this */
+		pr_debug("doing %s: %s = %s\n", doing, param, val);
+		return handle_unknown(param, val, doing);
 	}
 
 	pr_debug("Unknown argument `%s'\n", param);
@@ -175,17 +178,17 @@ static char *next_arg(char *args, char **param, char **val)
 }
 
 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
-int parse_args(const char *name,
+int parse_args(const char *doing,
 	       char *args,
 	       const struct kernel_param *params,
 	       unsigned num,
 	       s16 min_level,
 	       s16 max_level,
-	       int (*unknown)(char *param, char *val))
+	       int (*unknown)(char *param, char *val, const char *doing))
 {
 	char *param, *val;
 
-	pr_debug("Parsing ARGS: %s\n", args);
+	pr_debug("doing %s, parsing ARGS: %s\n", doing, args);
 
 	/* Chew leading spaces */
 	args = skip_spaces(args);
@@ -196,7 +199,7 @@ int parse_args(const char *name,
 
 		args = next_arg(args, &param, &val);
 		irq_was_disabled = irqs_disabled();
-		ret = parse_one(param, val, params, num,
+		ret = parse_one(param, val, doing, params, num,
 				min_level, max_level, unknown);
 		if (irq_was_disabled && !irqs_disabled()) {
 			printk(KERN_WARNING "parse_args(): option '%s' enabled "
@@ -205,19 +208,19 @@ int parse_args(const char *name,
 		switch (ret) {
 		case -ENOENT:
 			printk(KERN_ERR "%s: Unknown parameter `%s'\n",
-			       name, param);
+			       doing, param);
 			return ret;
 		case -ENOSPC:
 			printk(KERN_ERR
 			       "%s: `%s' too large for parameter `%s'\n",
-			       name, val ?: "", param);
+			       doing, val ?: "", param);
 			return ret;
 		case 0:
 			break;
 		default:
 			printk(KERN_ERR
 			       "%s: `%s' invalid for parameter `%s'\n",
-			       name, val ?: "", param);
+			       doing, val ?: "", param);
 			return ret;
 		}
 	}
-- 
1.7.7.6

[PATCH 07/11] dynamic_debug: make dynamic-debug work during module initialization

[jim.cromie]

From: Jim Cromie <jim.cromie@gmail.com>

This introduces a fake module param $module.dyndbg.  Its based upon
Thomas Renninger's $module.ddebug boot-time debugging patch from
https://lkml.org/lkml/2010/9/15/397

The 'fake' module parameter is provided for all modules, whether or
not they need it.  It is not explicitly added to each module, but is
implemented in 2 common callbacks invoked from parse_args.

Now dynamic_debug_init() directly calls parse_args(), which calls
ddebug_dyndbg_boot_params_cb().  This callback handles both bare and
module-prefixed dyndbg params immediately after the ddebug tables are
loaded, and ignores all other parameters. For example, the following
will enable pr_debug()s in 4 builtin modules, in the order given:

  dyndbg="module params +p; module aio +p" module.dyndbg=+p pci.dyndbg

A previous patch changed "ddebug_query" to "dyndbg"; since this new
callback handles it, we can drop the special case "ddebug_query" code.

For loadable modules, parse_args() in load_module() calls
ddebug_dyndbg_module_params_cb().  This handles bare dyndbg params as
passed from modprobe, and errors on other unknown params.

These callbacks need to know the module name, as provided by the
"doing" arg added in the previous patch.

For non CONFIG_DYNAMIC_DEBUG builds, the stub function accepts
and ignores $module.dyndbg params, other unknowns get -ENOENT.

If no param value is given (as in pci.dyndbg example above), "+p" is
assumed, which enables all pr_debug callsites in the module.

The dyndbg fake parameter is not shown in /sys/module/*/parameters,
thus it does not use any resources.  Changes to it are made via the
control file.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
CC: Thomas Renninger <trenn@suse.de>
CC: Rusty Russell <rusty@rustcorp.com.au>
---
 include/linux/dynamic_debug.h |   17 +++++++++++++
 kernel/module.c               |    2 +-
 lib/dynamic_debug.c           |   53 +++++++++++++++++++++++++++++++---------
 3 files changed, 59 insertions(+), 13 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index bf1b0fc..4697e4b 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -44,6 +44,9 @@ extern int ddebug_remove_module(const char *mod_name);
 extern __printf(2, 3)
 int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
 
+extern int ddebug_dyndbg_module_param_cb(char *param, char *val,
+					const char *modname);
+
 struct device;
 
 extern __printf(3, 4)
@@ -94,11 +97,25 @@ do {								\
 
 #else
 
+#include <linux/string.h>
+#include <linux/errno.h>
+
 static inline int ddebug_remove_module(const char *mod)
 {
 	return 0;
 }
 
+static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
+						const char *modname)
+{
+	if (strstr(param, "dyndbg")) {
+		pr_warn("dyndbg supported only in "
+			"CONFIG_DYNAMIC_DEBUG builds\n");
+		return 0; /* allow and ignore */
+	}
+	return -EINVAL;
+}
+
 #define dynamic_pr_debug(fmt, ...)					\
 	do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0)
 #define dynamic_dev_dbg(dev, fmt, ...)					\
diff --git a/kernel/module.c b/kernel/module.c
index 78ac6ec..a4e6097 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2953,7 +2953,7 @@ static struct module *load_module(void __user *umod,
 
 	/* Module is ready to execute: parsing args may do that. */
 	err = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
-			 -32768, 32767, NULL);
+			 -32768, 32767, &ddebug_dyndbg_module_param_cb);
 	if (err < 0)
 		goto unlink;
 
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 1435981..662204a 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -862,6 +862,41 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 }
 EXPORT_SYMBOL_GPL(ddebug_add_module);
 
+/* handle both dyndbg=".." and $module.dyndbg=".." params at boot */
+static int ddebug_dyndbg_boot_param_cb(char *param, char *val,
+				const char *unused)
+{
+	const char *modname = NULL;
+	char *sep;
+
+	sep = strchr(param, '.');
+	if (sep) {
+		*sep = '\0';
+		modname = param;
+		param = sep + 1;
+	}
+	if (strcmp(param, "dyndbg"))
+		return 0; /* skip all other params w/o error */
+
+	vpr_info("module: %s %s=\"%s\"\n", modname, param, val);
+
+	ddebug_exec_queries(val ? val : "+p");
+	return 0; /* query failure shouldnt stop module load */
+}
+
+/* handle dyndbg args to modprobe */
+int ddebug_dyndbg_module_param_cb(char *param, char *val, const char *doing)
+{
+	if (strcmp(param, "dyndbg"))
+		return -ENOENT;
+
+	vpr_info("module: %s %s=\"%s\"\n", doing, param, val);
+
+	ddebug_exec_queries((val ? val : "+p"), doing);
+
+	return 0; /* query failure shouldnt stop module load */
+}
+
 static void ddebug_table_free(struct ddebug_table *dt)
 {
 	list_del_init(&dt->link);
@@ -929,6 +964,7 @@ static int __init dynamic_debug_init(void)
 {
 	struct _ddebug *iter, *iter_start;
 	const char *modname = NULL;
+	char *cmdline;
 	int ret = 0;
 	int n = 0;
 
@@ -955,18 +991,10 @@ static int __init dynamic_debug_init(void)
 	if (ret)
 		goto out_free;
 
-	/* ddebug_query boot param got passed -> set it up */
-	if (ddebug_setup_string[0] != '\0') {
-		ret = ddebug_exec_queries(ddebug_setup_string);
-		if (ret < 0)
-			pr_warn("Invalid ddebug boot param %s",
-				ddebug_setup_string);
-		else
-			pr_info("%d changes by ddebug_query\n", ret);
-
-		/* keep tables even on ddebug_query parse error */
-		ret = 0;
-	}
+	cmdline = kstrdup(saved_command_line, GFP_KERNEL);
+	parse_args("dyndbg params", cmdline, NULL,
+		   0, 0, 0, &ddebug_dyndbg_boot_param_cb);
+	kfree(cmdline);
 
 out_free:
 	if (ret)
@@ -977,5 +1005,6 @@ out_free:
 }
 /* Allow early initialization for boot messages via boot param */
 arch_initcall(dynamic_debug_init);
+
 /* Debugfs setup must be done later */
 module_init(dynamic_debug_init_debugfs);
-- 
1.7.7.6

[PATCH 08/11] pnp: if CONFIG_DYNAMIC_DEBUG, use pnp.dyndbg instead of pnp.debug

[jim.cromie]

From: Jim Cromie <jim.cromie@gmail.com>

based upon https://lkml.org/lkml/2010/9/15/398

This patch splits control of pnp debug messages for 2 configs:

CONFIG_DYNAMIC_DEBUG:
  use pnp.dyndbg, using pnp.debug will warn
!CONFIG_DYNAMIC_DEBUG:
  use pnp.debug, using pnp.dyndbg will warn

2 separate boot options is perhaps suboptimal, but dyndbg is a 'fake'
parameter, and is special enough that adapting one to another is both
more suboptimal and harder to explain succinctly.

Thomas' original comments, still pertinent:

I wonder whether CONFIG_PNP_DEBUG_MESSAGES can vanish totally with
this or at some time. Only advantage having it is: If you are
restricted and your kernel must not exceed X bytes, you cannot compile
in PNP debug messages only, but you have to compile in all debug
messages.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
CC: Thomas Renninger <trenn@suse.de>
CC: Bjorn Helgaas <bhelgaas@google.com>
---
 Documentation/kernel-parameters.txt |   14 ++++++++------
 drivers/pnp/base.h                  |    8 ++++++--
 drivers/pnp/core.c                  |   12 ++++++++++++
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 82aa8ba..eb7d6c3 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2194,12 +2194,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			Override pmtimer IOPort with a hex value.
 			e.g. pmtmr=0x508
 
-	pnp.debug=1	[PNP]
-			Enable PNP debug messages (depends on the
-			CONFIG_PNP_DEBUG_MESSAGES option).  Change at run-time
-			via /sys/module/pnp/parameters/debug.  We always show
-			current resource usage; turning this on also shows
-			possible settings and some assignment information.
+	pnp.debug=1	[PNP] Enable PNP debug messages
+		        (depends on CONFIG_PNP_DEBUG_MESSAGES and
+			!CONFIG_DYNAMIC_DEBUG options.  If latter, use
+			pnp.dyndbg instead).  Change at run-time via
+			/sys/module/pnp/parameters/debug.  We always
+			show current resource usage; turning this on
+			also shows possible settings and some
+			assignment information.
 
 	pnpacpi=	[ACPI]
 			{ off }
diff --git a/drivers/pnp/base.h b/drivers/pnp/base.h
index fa4e0a5..28e98aa 100644
--- a/drivers/pnp/base.h
+++ b/drivers/pnp/base.h
@@ -173,12 +173,16 @@ struct pnp_resource *pnp_add_bus_resource(struct pnp_dev *dev,
 					  resource_size_t start,
 					  resource_size_t end);
 
-extern int pnp_debug;
-
+#if defined(CONFIG_DYNAMIC_DEBUG)
+#define pnp_dbg(dev, format, arg...)					\
+	({ dev_dbg(dev, format, ## arg); 0; })
+#else
 #if defined(CONFIG_PNP_DEBUG_MESSAGES)
+extern int pnp_debug;
 #define pnp_dbg(dev, format, arg...)					\
 	({ if (pnp_debug) dev_printk(KERN_DEBUG, dev, format, ## arg); 0; })
 #else
 #define pnp_dbg(dev, format, arg...)					\
 	({ if (0) dev_printk(KERN_DEBUG, dev, format, ## arg); 0; })
 #endif
+#endif
diff --git a/drivers/pnp/core.c b/drivers/pnp/core.c
index cb6ce42..838d82c 100644
--- a/drivers/pnp/core.c
+++ b/drivers/pnp/core.c
@@ -219,6 +219,18 @@ subsys_initcall(pnp_init);
 
 int pnp_debug;
 
+#if defined(CONFIG_DYNAMIC_DEBUG)
+static int __init pnp_debug_setup(char *__unused)
+{
+	pr_info("DYNAMIC_DEBUG enabled, use pnp.dyndbg instead\n");
+	return 1;
+}
+__setup("pnp.debug", pnp_debug_setup);
+
+#else
+
 #if defined(CONFIG_PNP_DEBUG_MESSAGES)
 module_param_named(debug, pnp_debug, int, 0644);
 #endif
+
+#endif
-- 
1.7.7.6

[PATCH 09/11] dynamic_debug: add modname arg to exec_query callchain

[jim.cromie]

From: Jim Cromie <jim.cromie@gmail.com>

Pass module name into ddebug_exec_queries(), ddebug_exec_query(), and
ddebug_parse_query() as separate parameter.  In ddebug_parse_query(),
the module name is added into the query struct before the query-string
is parsed.  This allows the query-string to be shorter:

instead of:
   $modname.dyndbg="module $modname +fp"
do this:
   $modname.dyndbg="+fp"

Omitting "module $modname" from the query string is actually required
for $modname.dyndbg rules; the set-only-once check added in a previous
patch will throw an error if its added again.  ddebug_query="..." has
no $modname associated with it, so the query string may include it.

This also fixes redundant "module $modname" otherwise needed to handle
multiple queries per string:

   $modname.dyndbg="func foo +fp; func bar +fp"

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c |   19 ++++++++++++-------
 1 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 662204a..8fcead5 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -338,7 +338,7 @@ static int check_set(const char **dest, char *src, char *name)
  * Returns 0 on success, <0 on error.
  */
 static int ddebug_parse_query(char *words[], int nwords,
-			       struct ddebug_query *query)
+			struct ddebug_query *query, const char *modname)
 {
 	unsigned int i;
 	int rc;
@@ -348,6 +348,10 @@ static int ddebug_parse_query(char *words[], int nwords,
 		return -EINVAL;
 	memset(query, 0, sizeof(*query));
 
+	if (modname)
+		/* support $modname.dyndbg=<multiple queries> */
+		query->module = modname;
+
 	for (i = 0 ; i < nwords ; i += 2) {
 		if (!strcmp(words[i], "func"))
 			rc = check_set(&query->function, words[i+1], "func");
@@ -444,7 +448,7 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
 	return 0;
 }
 
-static int ddebug_exec_query(char *query_string)
+static int ddebug_exec_query(char *query_string, const char *modname)
 {
 	unsigned int flags = 0, mask = 0;
 	struct ddebug_query query;
@@ -455,7 +459,7 @@ static int ddebug_exec_query(char *query_string)
 	nwords = ddebug_tokenize(query_string, words, MAXWORDS);
 	if (nwords <= 0)
 		return -EINVAL;
-	if (ddebug_parse_query(words, nwords-1, &query))
+	if (ddebug_parse_query(words, nwords-1, &query, modname))
 		return -EINVAL;
 	if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
 		return -EINVAL;
@@ -471,7 +475,7 @@ static int ddebug_exec_query(char *query_string)
    last error or number of matching callsites.  Module name is either
    in param (for boot arg) or perhaps in query string.
 */
-static int ddebug_exec_queries(char *query)
+static int ddebug_exec_queries(char *query, const char *modname)
 {
 	char *split;
 	int i, errs = 0, exitcode = 0, rc, nfound = 0;
@@ -487,7 +491,7 @@ static int ddebug_exec_queries(char *query)
 
 		vpr_info("query %d: \"%s\"\n", i, query);
 
-		rc = ddebug_exec_query(query);
+		rc = ddebug_exec_query(query, modname);
 		if (rc < 0) {
 			errs++;
 			exitcode = rc;
@@ -652,7 +656,7 @@ static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
 	tmpbuf[len] = '\0';
 	vpr_info("read %d bytes from userspace\n", (int)len);
 
-	ret = ddebug_exec_queries(tmpbuf);
+	ret = ddebug_exec_queries(tmpbuf, NULL);
 	kfree(tmpbuf);
 	if (ret < 0)
 		return ret;
@@ -880,7 +884,8 @@ static int ddebug_dyndbg_boot_param_cb(char *param, char *val,
 
 	vpr_info("module: %s %s=\"%s\"\n", modname, param, val);
 
-	ddebug_exec_queries(val ? val : "+p");
+	ddebug_exec_queries((val ? val : "+p"), modname);
+
 	return 0; /* query failure shouldnt stop module load */
 }
 
-- 
1.7.7.6

[PATCH 10/11] dynamic_debug: update Documentation/*, Kconfig.debug

[jim.cromie]

From: Jim Cromie <jim.cromie@gmail.com>

In dynamic-debug-howto.txt:

- add section: Debug Messages at Module Initialization Time
- update flags indicators in example outputs, from '-' to '=_'.
- make flags descriptions tabular
- add item on '_' flag-char
- add dyndbg, boot-args examples
- rewrap some paragraphs with long lines

In Kconfig.debug, note that compiling with -DDEBUG enables all
pr_debug()s in that code.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 Documentation/dynamic-debug-howto.txt |  155 ++++++++++++++++++++-------------
 lib/Kconfig.debug                     |   17 +++--
 2 files changed, 107 insertions(+), 65 deletions(-)

diff --git a/Documentation/dynamic-debug-howto.txt b/Documentation/dynamic-debug-howto.txt
index 74e6c77..235d963 100644
--- a/Documentation/dynamic-debug-howto.txt
+++ b/Documentation/dynamic-debug-howto.txt
@@ -2,17 +2,17 @@
 Introduction
 ============
 
-This document describes how to use the dynamic debug (ddebug) feature.
+This document describes how to use the dynamic debug (dyndbg) feature.
 
-Dynamic debug is designed to allow you to dynamically enable/disable kernel
-code to obtain additional kernel information. Currently, if
-CONFIG_DYNAMIC_DEBUG is set, then all pr_debug()/dev_dbg() calls can be
-dynamically enabled per-callsite.
+Dynamic debug is designed to allow you to dynamically enable/disable
+kernel code to obtain additional kernel information.  Currently, if
+CONFIG_DYNAMIC_DEBUG is set, then all pr_debug()/dev_dbg() calls can
+be dynamically enabled per-callsite.
 
 Dynamic debug has even more useful features:
 
- * Simple query language allows turning on and off debugging statements by
-   matching any combination of 0 or 1 of:
+ * Simple query language allows turning on and off debugging
+   statements by matching any combination of 0 or 1 of:
 
    - source filename
    - function name
@@ -20,17 +20,19 @@ Dynamic debug has even more useful features:
    - module name
    - format string
 
- * Provides a debugfs control file: <debugfs>/dynamic_debug/control which can be
-   read to display the complete list of known debug statements, to help guide you
+ * Provides a debugfs control file: <debugfs>/dynamic_debug/control
+   which can be read to display the complete list of known debug
+   statements, to help guide you
 
 Controlling dynamic debug Behaviour
 ===================================
 
 The behaviour of pr_debug()/dev_dbg()s are controlled via writing to a
-control file in the 'debugfs' filesystem. Thus, you must first mount the debugfs
-filesystem, in order to make use of this feature. Subsequently, we refer to the
-control file as: <debugfs>/dynamic_debug/control. For example, if you want to
-enable printing from source file 'svcsock.c', line 1603 you simply do:
+control file in the 'debugfs' filesystem. Thus, you must first mount
+the debugfs filesystem, in order to make use of this feature.
+Subsequently, we refer to the control file as:
+<debugfs>/dynamic_debug/control. For example, if you want to enable
+printing from source file 'svcsock.c', line 1603 you simply do:
 
 nullarbor:~ # echo 'file svcsock.c line 1603 +p' >
 				<debugfs>/dynamic_debug/control
@@ -44,15 +46,15 @@ nullarbor:~ # echo 'file svcsock.c wtf 1 +p' >
 Viewing Dynamic Debug Behaviour
 ===========================
 
-You can view the currently configured behaviour of all the debug statements
-via:
+You can view the currently configured behaviour of all the debug
+statements via:
 
 nullarbor:~ # cat <debugfs>/dynamic_debug/control
 # filename:lineno [module]function flags format
-/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup - "SVCRDMA Module Removed, deregister RPC RDMA transport\012"
-/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init - "\011max_inline       : %d\012"
-/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init - "\011sq_depth         : %d\012"
-/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init - "\011max_requests     : %d\012"
+/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup =_ "SVCRDMA Module Removed, deregister RPC RDMA transport\012"
+/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init =_ "\011max_inline       : %d\012"
+/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init =_ "\011sq_depth         : %d\012"
+/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init =_ "\011max_requests     : %d\012"
 ...
 
 
@@ -65,12 +67,12 @@ nullarbor:~ # grep -i rdma <debugfs>/dynamic_debug/control  | wc -l
 nullarbor:~ # grep -i tcp <debugfs>/dynamic_debug/control | wc -l
 42
 
-Note in particular that the third column shows the enabled behaviour
-flags for each debug statement callsite (see below for definitions of the
-flags).  The default value, no extra behaviour enabled, is "-".  So
-you can view all the debug statement callsites with any non-default flags:
+The third column shows the currently enabled flags for each debug
+statement callsite (see below for definitions of the flags).  The
+default value, with no flags enabled, is "=_".  So you can view all
+the debug statement callsites with any non-default flags:
 
-nullarbor:~ # awk '$3 != "-"' <debugfs>/dynamic_debug/control
+nullarbor:~ # awk '$3 != "=_"' <debugfs>/dynamic_debug/control
 # filename:lineno [module]function flags format
 /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process: st_sendto returned %d\012"
 
@@ -103,15 +105,14 @@ specifications, followed by a flags change specification.
 
 command ::= match-spec* flags-spec
 
-The match-spec's are used to choose a subset of the known dprintk()
+The match-spec's are used to choose a subset of the known pr_debug()
 callsites to which to apply the flags-spec.  Think of them as a query
 with implicit ANDs between each pair.  Note that an empty list of
-match-specs is possible, but is not very useful because it will not
-match any debug statement callsites.
+match-specs will select all debug statement callsites.
 
-A match specification comprises a keyword, which controls the attribute
-of the callsite to be compared, and a value to compare against.  Possible
-keywords are:
+A match specification comprises a keyword, which controls the
+attribute of the callsite to be compared, and a value to compare
+against.  Possible keywords are:
 
 match-spec ::= 'func' string |
 	       'file' string |
@@ -164,15 +165,15 @@ format
     characters (") or single quote characters (').
     Examples:
 
-    format svcrdma:	    // many of the NFS/RDMA server dprintks
-    format readahead	    // some dprintks in the readahead cache
+    format svcrdma:	    // many of the NFS/RDMA server pr_debugs
+    format readahead	    // some pr_debugs in the readahead cache
     format nfsd:\040SETATTR // one way to match a format with whitespace
     format "nfsd: SETATTR"  // a neater way to match a format with whitespace
     format 'nfsd: SETATTR'  // yet another way to match a format with whitespace
 
 line
     The given line number or range of line numbers is compared
-    against the line number of each dprintk() callsite.  A single
+    against the line number of each pr_debug() callsite.  A single
     line number matches the callsite line number exactly.  A
     range of line numbers matches any callsite between the first
     and last line number inclusive.  An empty first number means
@@ -188,52 +189,76 @@ The flags specification comprises a change operation followed
 by one or more flag characters.  The change operation is one
 of the characters:
 
--
-    remove the given flags
-
-+
-    add the given flags
-
-=
-    set the flags to the given flags
+  -    remove the given flags
+  +    add the given flags
+  =    set the flags to the given flags
 
 The flags are:
 
-f
-    Include the function name in the printed message
-l
-    Include line number in the printed message
-m
-    Include module name in the printed message
-p
-    Causes a printk() message to be emitted to dmesg
-t
-    Include thread ID in messages not generated from interrupt context
+  p    enables the pr_debug() callsite.
+  f    Include the function name in the printed message
+  l    Include line number in the printed message
+  m    Include module name in the printed message
+  t    Include thread ID in messages not generated from interrupt context
+  _    No flags are set. (Or'd with others on input)
 
-Note the regexp ^[-+=][flmpt]+$ matches a flags specification.
-Note also that there is no convenient syntax to remove all
-the flags at once, you need to use "-flmpt".
+For display, the flags are preceded by '='
+(mnemonic: what the flags are currently equal to).
 
+Note the regexp ^[-+=][flmpt_]+$ matches a flags specification.
+To clear all flags at once, use "=_" or "-flmpt".
 
-Debug messages during boot process
+
+Debug messages during Boot Process
 ==================================
 
-To be able to activate debug messages during the boot process,
-even before userspace and debugfs exists, use the boot parameter:
-ddebug_query="QUERY"
+To activate debug messages for core code and built-in modules during
+the boot process, even before userspace and debugfs exists, use the
+boot parameter: dyndbg="QUERY".
 
 QUERY follows the syntax described above, but must not exceed 1023
 characters. The enablement of debug messages is done as an arch_initcall.
 Thus you can enable debug messages in all code processed after this
 arch_initcall via this boot parameter.
+
 On an x86 system for example ACPI enablement is a subsys_initcall and
-ddebug_query="file ec.c +p"
+   dyndbg="file ec.c +p"
 will show early Embedded Controller transactions during ACPI setup if
 your machine (typically a laptop) has an Embedded Controller.
 PCI (or other devices) initialization also is a hot candidate for using
 this boot parameter for debugging purposes.
 
 
+Debug Messages at Module Initialization Time
+============================================
+
+For dynamically loaded modules, dyndbg given via modprobe enables
+its callsites before module initialization:
+
+1. # the parameter can be given permanently via /etc/modprobe.d/*.conf
+   options $module dyndbg=+pmflt
+   options $module dyndbg # defaults to +p
+
+2. # as an ordinary module parameter via modprobe
+   modprobe $module dyndbg=+pmfl
+
+Dyndbg flag settings are applied in the order given above, with last
+having final say.  This lets modprobe args (2) either supplement
+(dyndbg=+tfl) or override (dyndbg="=p_") flags in (1).
+
+The boot parameter form: $modname.dyndbg="value" must exclude "module
+$modname", as the $modname is taken from the param-name, and only 1
+spec of each type is allowed.
+
+The dyndbg option is not implemented as an ordinary module parameter
+and thus will not show up in /sys/module/$module_name/parameters/dyndbg
+
+For CONFIG_DYNAMIC_DEBUG kernels, any settings given at boot-time (or
+by -DDEBUG flag during compilation) can be disabled later via the
+sysfs interface if the debug messages are no longer needed:
+
+   echo "module module_name -p" > <debugfs>/dynamic_debug/control
+
 Examples
 ========
 
@@ -260,3 +285,15 @@ nullarbor:~ # echo -n 'func svc_process -p' >
 // enable messages for NFS calls READ, READLINK, READDIR and READDIR+.
 nullarbor:~ # echo -n 'format "nfsd: READ" +p' >
 				<debugfs>/dynamic_debug/control
+
+// enable all messages
+nullarbor:~ # echo -n '+p' > <debugfs>/dynamic_debug/control
+
+// add module, function to all enabled messages
+nullarbor:~ # echo -n '+mf' > <debugfs>/dynamic_debug/control
+
+// boot-args example, with newlines and comments for readability
+Kernel command line: ...
+  dyndbg="func i2c_del_adapter +p; func tboot_probe +p"
+  dynamic_debug.verbose=1	# see whats going on
+  nouveau.dyndbg		# implicit =+p
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index f7af95d..ed27521 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1204,8 +1204,13 @@ config DYNAMIC_DEBUG
 	  otherwise be available at runtime. These messages can then be
 	  enabled/disabled based on various levels of scope - per source file,
 	  function, module, format string, and line number. This mechanism
-	  implicitly enables all pr_debug() and dev_dbg() calls. The impact of
-	  this compile option is a larger kernel text size of about 2%.
+	  implicitly compiles in all pr_debug() and dev_dbg() calls, which
+	  enlarges the kernel text size by about 2%.
+
+	  If a source file is compiled with DEBUG flag set, any
+	  pr_debug() calls in it are enabled by default, but can be
+	  disabled at runtime as below.  Note that DEBUG flag is
+	  turned on by many CONFIG_*DEBUG* options.
 
 	  Usage:
 
@@ -1222,16 +1227,16 @@ config DYNAMIC_DEBUG
 	  lineno : line number of the debug statement
 	  module : module that contains the debug statement
 	  function : function that contains the debug statement
-          flags : 'p' means the line is turned 'on' for printing
+          flags : '=p' means the line is turned 'on' for printing
           format : the format used for the debug statement
 
 	  From a live system:
 
 		nullarbor:~ # cat <debugfs>/dynamic_debug/control
 		# filename:lineno [module]function flags format
-		fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
-		fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
-		fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
+		fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
+		fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
+		fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
 
 	  Example usage:
 
-- 
1.7.7.6

[PATCH 11/11] dynamic_debug: init with core_initcall, not arch_initcall

[jim.cromie]

From: Jim Cromie <jim.cromie@gmail.com>

Initializing dynamic_debug earlier makes pr_debug useful earlier
in boot process.  For example:

    dyndbg=" module params +p"

will enable parameter processing for initcall levels after core.
Note that this is too late to enable params processing for builtin
modules, which is a significant limitation, but its still
potentially useful.

RFC: This works for me on a 64 bit desktop and i586 SBC, but is
untested on other arches.  I presume there is or was a reason
it was done with arch_initcall, maybe the constraints have changed.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 8fcead5..747245d 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1009,7 +1009,7 @@ out_free:
 	return 0;
 }
 /* Allow early initialization for boot messages via boot param */
-arch_initcall(dynamic_debug_init);
+core_initcall(dynamic_debug_init);
 
 /* Debugfs setup must be done later */
 module_init(dynamic_debug_init_debugfs);
-- 
1.7.7.6

Re: [00/11] pr_debug during module initialization

[Rusty Russell]

On Wed, 14 Mar 2012 17:01:55 -0600, jim.cromie@gmail.com wrote:
> 
> This is 3rd revision of the dyndbg modinit patches, previously sent
> Dec 11.  Patches 1-17/25 sent then were added to driver-core-next,
> this set reworks the remainder.
> 
> It implements the "fake" module param approach proposed by
> Thomas Renninger, back in https://lkml.org/lkml/2010/9/15/397
> 
> This set is on top of linux-next, since that includes Pawel Moll's
> initcall-level params patch.  Im not using this feature, but I didnt
> know that when I started.
> 
> Rusty Russell did a partial review of 2nd rev (sent off-list), here:
> http://thread.gmane.org/gmane.linux.kernel/1262934
> This revision incorporates my understanding of his feedback.

The module parts seem fine.  The re-parsing of the commandline seems
weird:  I'd really rather see something in unknown_bootoption(), like:

	/* Unused module parameter. */
	if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
+               /* Check for <module>.dyndebug fake param */
+               dyndebug_parse(param, val);
		return 0;
        }

(Note that param will be the whole line here, eg "foo.dyndebug=+p", with
 val pointing just past the "=" (if any)).

Of course, that means the parsing happens at that "parse_args("Booting
kernel"...)" point in init/main.c, which may not suit.

Otherwise, all looks good!

Acked-by: Rusty Russell <rusty@rustcorp.com.au>

Cheers,
Rusty.
-- 
  How could I marry someone with more hair than me?  http://baldalex.org

Re: [00/11] pr_debug during module initialization

[Jim Cromie]

On Sun, Mar 18, 2012 at 8:04 PM, Rusty Russell <rusty@rustcorp.com.au> wrote:
> On Wed, 14 Mar 2012 17:01:55 -0600, jim.cromie@gmail.com wrote:
>>
>> This is 3rd revision of the dyndbg modinit patches, previously sent
>> Dec 11.  Patches 1-17/25 sent then were added to driver-core-next,
>> this set reworks the remainder.
>>
>> It implements the "fake" module param approach proposed by
>> Thomas Renninger, back in https://lkml.org/lkml/2010/9/15/397
>>
>> This set is on top of linux-next, since that includes Pawel Moll's
>> initcall-level params patch.  Im not using this feature, but I didnt
>> know that when I started.
>>
>> Rusty Russell did a partial review of 2nd rev (sent off-list), here:
>> http://thread.gmane.org/gmane.linux.kernel/1262934
>> This revision incorporates my understanding of his feedback.
>
> The module parts seem fine.  The re-parsing of the commandline seems
> weird:  I'd really rather see something in unknown_bootoption(), like:
>
>        /* Unused module parameter. */
>        if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
> +               /* Check for <module>.dyndebug fake param */
> +               dyndebug_parse(param, val);
>                return 0;
>        }
>
> (Note that param will be the whole line here, eg "foo.dyndebug=+p", with
>  val pointing just past the "=" (if any)).
>
> Of course, that means the parsing happens at that "parse_args("Booting
> kernel"...)" point in init/main.c, which may not suit.
>

That is too early - the dyndbg rules cant be activated
until dynamic_debug_init() runs, which is currently an
arch_initcall(dynamic_debug_init);

Patch 11 makes it core-initcall, (which Im not sure is ok
for all cases, but works for me), I also tried it with
early_initcall (and that worked too)
but I think thats still after the Booting kernel parse.

I *could* capture the dyndbg options during Booting kernel
parse, and activate them once the tables are loaded,
but this seems convoluted.

Thomas' original approach (iirc, Id have to dig for the patches)
was to reuse parse_one after filtering for dyndbg params in
a "private" parse-args. After your earlier suggestion to use a
callback, it occurred to me that just reusing parse_args would
work, be fairly minimal (only 2 lines in dynamic_debug_init())
and its already called a bunch of times; Booting kernel,
module-load, and do-initcall-level (in Pawel's patch).
Pawels patch doesnt do anything to avoid reparsing
boot-time params.

Does this change your weirdness assessment ?

BTW, I think I can now drop ddebug_setup_string, ddebug_setup_query,
and __setup("ddebug_query="...)



Lastly, my earlier rev handled  foo.dyndbg params
for loadable modules.  I took that out cuz
Documentation/kernel-parameters.txt says thats
for builtins (only, as I read it), and treating foo.dyndbg
differently should be done w/o discussion.

Is there a reason why foo.knownparam=val is not handled ?
When I had it in, it was processed before modprobe args
IIRC, it was /etc/modprobe.d/*, foo.dyndbg in boot-args,
then modprobe args, which seemed correct - it let each override the
previous settings.


> Otherwise, all looks good!
>
> Acked-by: Rusty Russell <rusty@rustcorp.com.au>

thanks.  I guess the Ack (vs SOB) means that Jason should
forward it on to Greg as a single set ?
(subject to his Ack of course)

>
> Cheers,
> Rusty.
> --
>  How could I marry someone with more hair than me?  http://baldalex.org

Re: [00/11] pr_debug during module initialization

[Rusty Russell]

On Mon, 19 Mar 2012 00:17:29 -0600, Jim Cromie <jim.cromie@gmail.com> wrote:
> On Sun, Mar 18, 2012 at 8:04 PM, Rusty Russell <rusty@rustcorp.com.au> wrote:
> > The module parts seem fine.  The re-parsing of the commandline seems
> > weird:  I'd really rather see something in unknown_bootoption(), like:
> >
> >        /* Unused module parameter. */
> >        if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
> > +               /* Check for <module>.dyndebug fake param */
> > +               dyndebug_parse(param, val);
> >                return 0;
> >        }
> 
> That is too early - the dyndbg rules cant be activated
> until dynamic_debug_init() runs, which is currently an
> arch_initcall(dynamic_debug_init);
> 
> Patch 11 makes it core-initcall, (which Im not sure is ok
> for all cases, but works for me), I also tried it with
> early_initcall (and that worked too)
> but I think thats still after the Booting kernel parse.

Indeed.  OK, that's fine then.

> I *could* capture the dyndbg options during Booting kernel
> parse, and activate them once the tables are loaded,
> but this seems convoluted.

Agreed.

> a "private" parse-args. After your earlier suggestion to use a
> callback, it occurred to me that just reusing parse_args would
> work, be fairly minimal (only 2 lines in dynamic_debug_init())
> and its already called a bunch of times; Booting kernel,
> module-load, and do-initcall-level (in Pawel's patch).
> Pawels patch doesnt do anything to avoid reparsing
> boot-time params.
> 
> Does this change your weirdness assessment ?

It's still weird to re-parse, but with a comment explaining that we
need to do it again after dynamic_debug_init().  Unless we can call
that explicitly before parse_args().
> Lastly, my earlier rev handled  foo.dyndbg params
> for loadable modules.  I took that out cuz
> Documentation/kernel-parameters.txt says thats
> for builtins (only, as I read it), and treating foo.dyndbg
> differently should be done w/o discussion.

Yes, when a module 'foo' declares it has a parameter 'bar', it becomes
'foo.bar' if the module is built-in, and just 'bar' if the module is
loaded.

Furthermore, modprobe reads /proc/cmdline when loading foo, looking for
"foo.*" to add to the modprobe arguments.

> > Otherwise, all looks good!
> >
> > Acked-by: Rusty Russell <rusty@rustcorp.com.au>
> 
> thanks.  I guess the Ack (vs SOB) means that Jason should
> forward it on to Greg as a single set ?
> (subject to his Ack of course)

I assumed it would go via Jason.  Otherwise, get his ack and resend to
me.

Thanks,
Rusty.
-- 
  How could I marry someone with more hair than me?  http://baldalex.org

Re: [00/11] pr_debug during module initialization

[Jason Baron]

On Wed, Mar 14, 2012 at 05:01:55PM -0600, jim.cromie@gmail.com wrote:
> This is 3rd revision of the dyndbg modinit patches, previously sent
> Dec 11.  Patches 1-17/25 sent then were added to driver-core-next,
> this set reworks the remainder.
> 
> It implements the "fake" module param approach proposed by
> Thomas Renninger, back in https://lkml.org/lkml/2010/9/15/397
> 

Hi,

I'm wondering, if we leave the cmdline parameter: 'ddebug_query=' around
for a bit before removing it, so it doesn't get dropped too suddenly.
Perhaps, we add a warning msg, for people that are still using it
for a few releases warning that it is deprecated, before dropping it.

Also, let's add the 'dyndbg=' syntax to Documentation/kernel-parameters.txt.

A previous version had a build-time error if a module used 'dyndbg' as a
module param - why did that get dropped?

Thanks!

-Jason

Re: [00/11] pr_debug during module initialization

[Jim Cromie]

On Fri, Mar 23, 2012 at 2:27 PM, Jason Baron <jbaron@redhat.com> wrote:
> On Wed, Mar 14, 2012 at 05:01:55PM -0600, jim.cromie@gmail.com wrote:
>> This is 3rd revision of the dyndbg modinit patches, previously sent
>> Dec 11.  Patches 1-17/25 sent then were added to driver-core-next,
>> this set reworks the remainder.
>>
>> It implements the "fake" module param approach proposed by
>> Thomas Renninger, back in https://lkml.org/lkml/2010/9/15/397
>>
>
> Hi,
>
> I'm wondering, if we leave the cmdline parameter: 'ddebug_query=' around
> for a bit before removing it, so it doesn't get dropped too suddenly.
> Perhaps, we add a warning msg, for people that are still using it
> for a few releases warning that it is deprecated, before dropping it.
>

OK, thats reasonable.  I'll explicitly deprecate it in
Doc/feature-removal-schedule.  What is the default
deprecation time, 2 releases ?

Assuming this patchset is for 3.4, I'll say 3.6 unless someone disagrees.

> Also, let's add the 'dyndbg=' syntax to Documentation/kernel-parameters.txt.
>

oops.  that got dropped accidentally.

> A previous version had a build-time error if a module used 'dyndbg' as a
> module param - why did that get dropped?

Rusty expressed view that if developers add it, they meant it.
He also said the macro was redundant with another,
but I didnt look further cuz of the 1st point.


>
> Thanks!
>
> -Jason

Re: [00/11] pr_debug during module initialization

[Rusty Russell]

On Fri, 23 Mar 2012 18:12:51 -0600, Jim Cromie <jim.cromie@gmail.com> wrote:
> > A previous version had a build-time error if a module used 'dyndbg' as a
> > module param - why did that get dropped?
> 
> Rusty expressed view that if developers add it, they meant it.
> He also said the macro was redundant with another,
> but I didnt look further cuz of the 1st point.

Yeah, it was ugly overkill.  I can't see someone accidently overriding
dyndbg, and let's assume that they know what they're doing (who knows,
they might want to enhance the parsing before calling the real dyndbg
parser).

Cheers,
Rusty.
-- 
  How could I marry someone with more hair than me?  http://baldalex.org