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Subject[PATCH] Dynamic debug: Add more flags
Date
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: Bart Van Assche <bvanassche@acm.org>
Cc: Greg Banks <gnb@sgi.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Konrad Rzeszutek Wilk <konrad@darnok.org>
---
Documentation/dynamic-debug-howto.txt | 12 +++++-
include/linux/dynamic_debug.h | 8 ++++-
lib/dynamic_debug.c | 60 ++++++++++++++++++++++++++++-----
3 files changed, 68 insertions(+), 12 deletions(-)
diff --git a/Documentation/dynamic-debug-howto.txt b/Documentation/dynamic-debug-howto.txt
index 58ea64a..e6c4b75 100644
--- a/Documentation/dynamic-debug-howto.txt
+++ b/Documentation/dynamic-debug-howto.txt
@@ -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
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 1c70028..0c9653f 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -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)


diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index b335acb..863c834 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -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 '+':
@@ -358,13 +370,14 @@ 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;
- break;
- default:
- return -EINVAL;
+ for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
+ if (*str == opt_array[i].opt_char) {
+ flags |= opt_array[i].flag;
+ break;
+ }
}
+ if (i < 0)
+ return -EINVAL;
}
if (flags == 0)
return -EINVAL;
@@ -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)
{
--
1.7.1


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