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Commit 8ba6ebf5 authored by Bart Van Assche's avatar Bart Van Assche Committed by Greg Kroah-Hartman
Browse files

Dynamic debug: Add more flags 



Add flags that allow the user to specify via debugfs whether or not the
module name, function name, line number and/or thread ID have to be
included in the printed message.

Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Cc: Greg Banks <gnb@fmeh.org>
Cc: Konrad Rzeszutek Wilk <konrad@darnok.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 9b99b7f8

Documentation/dynamic-debug-howto.txt

+10 −2
Original line number Diff line number Diff line
@@ -205,12 +205,20 @@ of the characters: 


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



Note the regexp ^[-+=][scp]+$ matches a flags specification.

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 "-psc".

the flags at once, you need to use "-flmpt".





Debug messages during boot process

include/linux/dynamic_debug.h

+7 −1
Original line number Diff line number Diff line
@@ -31,6 +31,10 @@ struct _ddebug { 
	 * writes commands to <debugfs>/dynamic_debug/control

	 */

#define _DPRINTK_FLAGS_PRINT   (1<<0)  /* printk() a message using the format */

#define _DPRINTK_FLAGS_INCL_MODNAME	(1<<1)

#define _DPRINTK_FLAGS_INCL_FUNCNAME	(1<<2)

#define _DPRINTK_FLAGS_INCL_LINENO	(1<<3)

#define _DPRINTK_FLAGS_INCL_TID		(1<<4)

#define _DPRINTK_FLAGS_DEFAULT 0

	unsigned int flags:8;

	char enabled;
@@ -42,6 +46,8 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n, 


#if defined(CONFIG_DYNAMIC_DEBUG)

extern int ddebug_remove_module(const char *mod_name);

extern int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)

	__attribute__ ((format (printf, 2, 3)));



#define dynamic_pr_debug(fmt, ...) do {					\

	static struct _ddebug descriptor				\
@@ -50,7 +56,7 @@ extern int ddebug_remove_module(const char *mod_name); 
	{ KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__,		\

		_DPRINTK_FLAGS_DEFAULT };				\

	if (unlikely(descriptor.enabled))				\

		printk(KERN_DEBUG pr_fmt(fmt),	##__VA_ARGS__);		\

		__dynamic_pr_debug(&descriptor, pr_fmt(fmt), ##__VA_ARGS__); \

	} while (0)

lib/dynamic_debug.c

+51 −9
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
 * Copyright (C) 2008 Jason Baron <jbaron@redhat.com>

 * By Greg Banks <gnb@melbourne.sgi.com>

 * Copyright (c) 2008 Silicon Graphics Inc.  All Rights Reserved.

 * Copyright (C) 2011 Bart Van Assche.  All Rights Reserved.

 */



#include <linux/kernel.h>
@@ -27,6 +28,7 @@ 
#include <linux/debugfs.h>

#include <linux/slab.h>

#include <linux/jump_label.h>

#include <linux/hardirq.h>



extern struct _ddebug __start___verbose[];

extern struct _ddebug __stop___verbose[];
@@ -63,15 +65,25 @@ static inline const char *basename(const char *path) 
	return tail ? tail+1 : path;

}



static struct { unsigned flag:8; char opt_char; } opt_array[] = {

	{ _DPRINTK_FLAGS_PRINT, 'p' },

	{ _DPRINTK_FLAGS_INCL_MODNAME, 'm' },

	{ _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },

	{ _DPRINTK_FLAGS_INCL_LINENO, 'l' },

	{ _DPRINTK_FLAGS_INCL_TID, 't' },

};



/* format a string into buf[] which describes the _ddebug's flags */

static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,

				    size_t maxlen)

{

	char *p = buf;

	int i;



	BUG_ON(maxlen < 4);

	if (dp->flags & _DPRINTK_FLAGS_PRINT)

		*p++ = 'p';

	for (i = 0; i < ARRAY_SIZE(opt_array); ++i)

		if (dp->flags & opt_array[i].flag)

			*p++ = opt_array[i].opt_char;

	if (p == buf)

		*p++ = '-';

	*p = '\0';
@@ -343,7 +355,7 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp, 
			       unsigned int *maskp)

{

	unsigned flags = 0;

	int op = '=';

	int op = '=', i;



	switch (*str) {

	case '+':
@@ -358,14 +370,15 @@ static int ddebug_parse_flags(const char *str, unsigned int *flagsp, 
		printk(KERN_INFO "%s: op='%c'\n", __func__, op);



	for ( ; *str ; ++str) {

		switch (*str) {

		case 'p':

			flags |= _DPRINTK_FLAGS_PRINT;

		for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {

			if (*str == opt_array[i].opt_char) {

				flags |= opt_array[i].flag;

				break;

		default:

			return -EINVAL;

			}

		}

		if (i < 0)

			return -EINVAL;

	}

	if (flags == 0)

		return -EINVAL;

	if (verbose)
@@ -413,6 +426,35 @@ static int ddebug_exec_query(char *query_string) 
	return 0;

}



int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)

{

	va_list args;

	int res;



	BUG_ON(!descriptor);

	BUG_ON(!fmt);



	va_start(args, fmt);

	res = printk(KERN_DEBUG);

	if (descriptor->flags & _DPRINTK_FLAGS_INCL_TID) {

		if (in_interrupt())

			res += printk(KERN_CONT "<intr> ");

		else

			res += printk(KERN_CONT "[%d] ", task_pid_vnr(current));

	}

	if (descriptor->flags & _DPRINTK_FLAGS_INCL_MODNAME)

		res += printk(KERN_CONT "%s:", descriptor->modname);

	if (descriptor->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)

		res += printk(KERN_CONT "%s:", descriptor->function);

	if (descriptor->flags & _DPRINTK_FLAGS_INCL_LINENO)

		res += printk(KERN_CONT "%d ", descriptor->lineno);

	res += vprintk(fmt, args);

	va_end(args);



	return res;

}

EXPORT_SYMBOL(__dynamic_pr_debug);



static __initdata char ddebug_setup_string[1024];

static __init int ddebug_setup_query(char *str)

{