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driver core: basic infrastructure for per-module dynamic debug messages

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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>
This commit is contained in:
Jason Baron 2008-08-12 16:46:19 -04:00 committed by Greg Kroah-Hartman
parent 33376c1c04
commit 346e15beb5
14 changed files with 700 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
Documentation/kernel-parameters.txt
View File

@ -1713,6 +1713,11 @@ and is between 256 and 4096 characters. It is defined in the file
autoconfiguration.
Ranges are in pairs (memory base and size).
dynamic_printk
Enables pr_debug()/dev_dbg() calls if
CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
be switched on/off via <debugfs>/dynamic_printk/modules
print-fatal-signals=
[KNL] debug: print fatal signals
print-fatal-signals=1: print segfault info to

10
include/asm-generic/vmlinux.lds.h
View File

@ -268,7 +268,15 @@
CPU_DISCARD(init.data) \
CPU_DISCARD(init.rodata) \
MEM_DISCARD(init.data) \
MEM_DISCARD(init.rodata)
MEM_DISCARD(init.rodata) \
/* implement dynamic printk debug */ \
VMLINUX_SYMBOL(__start___verbose_strings) = .; \
*(__verbose_strings) \
VMLINUX_SYMBOL(__stop___verbose_strings) = .; \
. = ALIGN(8); \
VMLINUX_SYMBOL(__start___verbose) = .; \
*(__verbose) \
VMLINUX_SYMBOL(__stop___verbose) = .;
#define INIT_TEXT \
*(.init.text) \

6
include/linux/device.h
View File

@ -550,7 +550,11 @@ extern const char *dev_driver_string(const struct device *dev);
#define dev_info(dev, format, arg...) \
dev_printk(KERN_INFO , dev , format , ## arg)
#ifdef DEBUG
#if defined(CONFIG_DYNAMIC_PRINTK_DEBUG)
#define dev_dbg(dev, format, ...) do { \
dynamic_dev_dbg(dev, format, ##__VA_ARGS__); \
} while (0)
#elif defined(DEBUG)
#define dev_dbg(dev, format, arg...) \
dev_printk(KERN_DEBUG , dev , format , ## arg)
#else

93
include/linux/dynamic_printk.h Normal file
View File

@ -0,0 +1,93 @@
#ifndef _DYNAMIC_PRINTK_H
#define _DYNAMIC_PRINTK_H
#define DYNAMIC_DEBUG_HASH_BITS 6
#define DEBUG_HASH_TABLE_SIZE (1 << DYNAMIC_DEBUG_HASH_BITS)
#define TYPE_BOOLEAN 1
#define DYNAMIC_ENABLED_ALL 0
#define DYNAMIC_ENABLED_NONE 1
#define DYNAMIC_ENABLED_SOME 2
extern int dynamic_enabled;
/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
* bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
* use independent hash functions, to reduce the chance of false positives.
*/
extern long long dynamic_printk_enabled;
extern long long dynamic_printk_enabled2;
struct mod_debug {
char *modname;
char *logical_modname;
char *flag_names;
int type;
int hash;
int hash2;
} __attribute__((aligned(8)));
int register_dynamic_debug_module(char *mod_name, int type, char *share_name,
char *flags, int hash, int hash2);
#if defined(CONFIG_DYNAMIC_PRINTK_DEBUG)
extern int unregister_dynamic_debug_module(char *mod_name);
extern int __dynamic_dbg_enabled_helper(char *modname, int type,
int value, int hash);
#define __dynamic_dbg_enabled(module, type, value, level, hash) ({ \
int __ret = 0; \
if (unlikely((dynamic_printk_enabled & (1LL << DEBUG_HASH)) && \
(dynamic_printk_enabled2 & (1LL << DEBUG_HASH2)))) \
__ret = __dynamic_dbg_enabled_helper(module, type, \
value, hash);\
__ret; })
#define dynamic_pr_debug(fmt, ...) do { \
static char mod_name[] \
__attribute__((section("__verbose_strings"))) \
= KBUILD_MODNAME; \
static struct mod_debug descriptor \
__used \
__attribute__((section("__verbose"), aligned(8))) = \
{ mod_name, mod_name, NULL, TYPE_BOOLEAN, DEBUG_HASH, DEBUG_HASH2 };\
if (__dynamic_dbg_enabled(KBUILD_MODNAME, TYPE_BOOLEAN, \
0, 0, DEBUG_HASH)) \
printk(KERN_DEBUG KBUILD_MODNAME ":" fmt, \
##__VA_ARGS__); \
} while (0)
#define dynamic_dev_dbg(dev, format, ...) do { \
static char mod_name[] \
__attribute__((section("__verbose_strings"))) \
= KBUILD_MODNAME; \
static struct mod_debug descriptor \
__used \
__attribute__((section("__verbose"), aligned(8))) = \
{ mod_name, mod_name, NULL, TYPE_BOOLEAN, DEBUG_HASH, DEBUG_HASH2 };\
if (__dynamic_dbg_enabled(KBUILD_MODNAME, TYPE_BOOLEAN, \
0, 0, DEBUG_HASH)) \
dev_printk(KERN_DEBUG, dev, \
KBUILD_MODNAME ": " format, \
##__VA_ARGS__); \
} while (0)
#else
static inline int unregister_dynamic_debug_module(const char *mod_name)
{
return 0;
}
static inline int __dynamic_dbg_enabled_helper(char *modname, int type,
int value, int hash)
{
return 0;
}
#define __dynamic_dbg_enabled(module, type, value, level, hash) ({ 0; })
#define dynamic_pr_debug(fmt, ...) do { } while (0)
#define dynamic_dev_dbg(dev, format, ...) do { } while (0)
#endif
#endif

7
include/linux/kernel.h
View File

@ -16,6 +16,7 @@
#include <linux/log2.h>
#include <linux/typecheck.h>
#include <linux/ratelimit.h>
#include <linux/dynamic_printk.h>
#include <asm/byteorder.h>
#include <asm/bug.h>
@ -303,8 +304,12 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
#define pr_info(fmt, arg...) \
printk(KERN_INFO fmt, ##arg)
#ifdef DEBUG
/* If you are writing a driver, please use dev_dbg instead */
#if defined(CONFIG_DYNAMIC_PRINTK_DEBUG)
#define pr_debug(fmt, ...) do { \
dynamic_pr_debug(fmt, ##__VA_ARGS__); \
} while (0)
#elif defined(DEBUG)
#define pr_debug(fmt, arg...) \
printk(KERN_DEBUG fmt, ##arg)
#else

1
include/linux/module.h
View File

@ -345,7 +345,6 @@ struct module
/* Reference counts */
struct module_ref ref[NR_CPUS];
#endif
};
#ifndef MODULE_ARCH_INIT
#define MODULE_ARCH_INIT {}

31
kernel/module.c
View File

@ -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;

55
lib/Kconfig.debug
View File

@ -807,6 +807,61 @@ menuconfig BUILD_DOCSRC
Say N if you are unsure.
config DYNAMIC_PRINTK_DEBUG
bool "Enable dynamic printk() call support"
default n
depends on PRINTK
select PRINTK_DEBUG
help
Compiles debug level messages into the kernel, which would not
otherwise be available at runtime. These messages can then be
enabled/disabled on a per module basis. 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%.
Usage:
Dynamic debugging is controlled by the debugfs file,
dynamic_printk/modules. This file contains a list of the modules that
can be enabled. The format of the file is the module name, followed
by a set of flags that can be enabled. The first flag is always the
'enabled' flag. For example:
<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
From a live system:
snd_hda_intel enabled=0
fixup enabled=0
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.
source "samples/Kconfig"
source "lib/Kconfig.kgdb"

2
lib/Makefile
View File

@ -81,6 +81,8 @@ obj-$(CONFIG_HAVE_LMB) += lmb.o
obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
obj-$(CONFIG_DYNAMIC_PRINTK_DEBUG) += dynamic_printk.o
hostprogs-y := gen_crc32table
clean-files := crc32table.h

418
lib/dynamic_printk.c Normal file
View File

@ -0,0 +1,418 @@
/*
* lib/dynamic_printk.c
*
* make pr_debug()/dev_dbg() calls runtime configurable based upon their
* their source module.
*
* Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/fs.h>
extern struct mod_debug __start___verbose[];
extern struct mod_debug __stop___verbose[];
struct debug_name {
struct hlist_node hlist;
struct hlist_node hlist2;
int hash1;
int hash2;
char *name;
int enable;
int type;
};
static int nr_entries;
static int num_enabled;
int dynamic_enabled = DYNAMIC_ENABLED_NONE;
static struct hlist_head module_table[DEBUG_HASH_TABLE_SIZE] =
{ [0 ... DEBUG_HASH_TABLE_SIZE-1] = HLIST_HEAD_INIT };
static struct hlist_head module_table2[DEBUG_HASH_TABLE_SIZE] =
{ [0 ... DEBUG_HASH_TABLE_SIZE-1] = HLIST_HEAD_INIT };
static DECLARE_MUTEX(debug_list_mutex);
/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
* bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
* use independent hash functions, to reduce the chance of false positives.
*/
long long dynamic_printk_enabled;
EXPORT_SYMBOL_GPL(dynamic_printk_enabled);
long long dynamic_printk_enabled2;
EXPORT_SYMBOL_GPL(dynamic_printk_enabled2);
/* returns the debug module pointer. */
static struct debug_name *find_debug_module(char *module_name)
{
int i;
struct hlist_head *head;
struct hlist_node *node;
struct debug_name *element;
element = NULL;
for (i = 0; i < DEBUG_HASH_TABLE_SIZE; i++) {
head = &module_table[i];
hlist_for_each_entry_rcu(element, node, head, hlist)
if (!strcmp(element->name, module_name))
return element;
}
return NULL;
}
/* returns the debug module pointer. */
static struct debug_name *find_debug_module_hash(char *module_name, int hash)
{
struct hlist_head *head;
struct hlist_node *node;
struct debug_name *element;
element = NULL;
head = &module_table[hash];
hlist_for_each_entry_rcu(element, node, head, hlist)
if (!strcmp(element->name, module_name))
return element;
return NULL;
}
/* caller must hold mutex*/
static int __add_debug_module(char *mod_name, int hash, int hash2)
{
struct debug_name *new;
char *module_name;
int ret = 0;
if (find_debug_module(mod_name)) {
ret = -EINVAL;
goto out;
}
module_name = kmalloc(strlen(mod_name) + 1, GFP_KERNEL);
if (!module_name) {
ret = -ENOMEM;
goto out;
}
module_name = strcpy(module_name, mod_name);
module_name[strlen(mod_name)] = '\0';
new = kzalloc(sizeof(struct debug_name), GFP_KERNEL);
if (!new) {
kfree(module_name);
ret = -ENOMEM;
goto out;
}
INIT_HLIST_NODE(&new->hlist);
INIT_HLIST_NODE(&new->hlist2);
new->name = module_name;
new->hash1 = hash;
new->hash2 = hash2;
hlist_add_head_rcu(&new->hlist, &module_table[hash]);
hlist_add_head_rcu(&new->hlist2, &module_table2[hash2]);
nr_entries++;
out:
return ret;
}
int unregister_dynamic_debug_module(char *mod_name)
{
struct debug_name *element;
int ret = 0;
down(&debug_list_mutex);
element = find_debug_module(mod_name);
if (!element) {
ret = -EINVAL;
goto out;
}
hlist_del_rcu(&element->hlist);
hlist_del_rcu(&element->hlist2);
synchronize_rcu();
kfree(element->name);
if (element->enable)
num_enabled--;
kfree(element);
nr_entries--;
out:
up(&debug_list_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(unregister_dynamic_debug_module);
int register_dynamic_debug_module(char *mod_name, int type, char *share_name,
char *flags, int hash, int hash2)
{
struct debug_name *elem;
int ret = 0;
down(&debug_list_mutex);
elem = find_debug_module(mod_name);
if (!elem) {
if (__add_debug_module(mod_name, hash, hash2))
goto out;
elem = find_debug_module(mod_name);
if (dynamic_enabled == DYNAMIC_ENABLED_ALL &&
!strcmp(mod_name, share_name)) {
elem->enable = true;
num_enabled++;
}
}
elem->type |= type;
out:
up(&debug_list_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(register_dynamic_debug_module);
int __dynamic_dbg_enabled_helper(char *mod_name, int type, int value, int hash)
{
struct debug_name *elem;
int ret = 0;
if (dynamic_enabled == DYNAMIC_ENABLED_ALL)
return 1;
rcu_read_lock();
elem = find_debug_module_hash(mod_name, hash);
if (elem && elem->enable)
ret = 1;
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(__dynamic_dbg_enabled_helper);
static void set_all(bool enable)
{
struct debug_name *e;
struct hlist_node *node;
int i;
long long enable_mask;
for (i = 0; i < DEBUG_HASH_TABLE_SIZE; i++) {
if (module_table[i].first != NULL) {
hlist_for_each_entry(e, node, &module_table[i], hlist) {
e->enable = enable;
}
}
}
if (enable)
enable_mask = ULLONG_MAX;
else
enable_mask = 0;
dynamic_printk_enabled = enable_mask;
dynamic_printk_enabled2 = enable_mask;
}
static int disabled_hash(int i, bool first_table)
{
struct debug_name *e;
struct hlist_node *node;
if (first_table) {
hlist_for_each_entry(e, node, &module_table[i], hlist) {
if (e->enable)
return 0;
}
} else {
hlist_for_each_entry(e, node, &module_table2[i], hlist2) {
if (e->enable)
return 0;
}
}
return 1;
}
static ssize_t pr_debug_write(struct file *file, const char __user *buf,
size_t length, loff_t *ppos)
{
char *buffer, *s, *value_str, *setting_str;
int err, value;
struct debug_name *elem = NULL;
int all = 0;
if (length > PAGE_SIZE || length < 0)
return -EINVAL;
buffer = (char *)__get_free_page(GFP_KERNEL);
if (!buffer)
return -ENOMEM;
err = -EFAULT;
if (copy_from_user(buffer, buf, length))
goto out;
err = -EINVAL;
if (length < PAGE_SIZE)
buffer[length] = '\0';
else if (buffer[PAGE_SIZE-1])
goto out;
err = -EINVAL;
down(&debug_list_mutex);
if (strncmp("set", buffer, 3))
goto out_up;
s = buffer + 3;
setting_str = strsep(&s, "=");
if (s == NULL)
goto out_up;
setting_str = strstrip(setting_str);
value_str = strsep(&s, " ");
if (s == NULL)
goto out_up;
s = strstrip(s);
if (!strncmp(s, "all", 3))
all = 1;
else
elem = find_debug_module(s);
if (!strncmp(setting_str, "enable", 6)) {
value = !!simple_strtol(value_str, NULL, 10);
if (all) {
if (value) {
set_all(true);
num_enabled = nr_entries;
dynamic_enabled = DYNAMIC_ENABLED_ALL;
} else {
set_all(false);
num_enabled = 0;
dynamic_enabled = DYNAMIC_ENABLED_NONE;
}
err = 0;
} else {
if (elem) {
if (value && (elem->enable == 0)) {
dynamic_printk_enabled |=
(1LL << elem->hash1);
dynamic_printk_enabled2 |=
(1LL << elem->hash2);
elem->enable = 1;
num_enabled++;
dynamic_enabled = DYNAMIC_ENABLED_SOME;
err = 0;
printk(KERN_DEBUG
"debugging enabled for module %s",
elem->name);
} else if (!value && (elem->enable == 1)) {
elem->enable = 0;
num_enabled--;
if (disabled_hash(elem->hash1, true))
dynamic_printk_enabled &=
~(1LL << elem->hash1);
if (disabled_hash(elem->hash2, false))
dynamic_printk_enabled2 &=
~(1LL << elem->hash2);
if (num_enabled)
dynamic_enabled =
DYNAMIC_ENABLED_SOME;
else
dynamic_enabled =
DYNAMIC_ENABLED_NONE;
err = 0;
printk(KERN_DEBUG
"debugging disabled for module "
"%s", elem->name);
}
}
}
}
if (!err)
err = length;
out_up:
up(&debug_list_mutex);
out:
free_page((unsigned long)buffer);
return err;
}
static void *pr_debug_seq_start(struct seq_file *f, loff_t *pos)
{
return (*pos < DEBUG_HASH_TABLE_SIZE) ? pos : NULL;
}
static void *pr_debug_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
(*pos)++;
if (*pos >= DEBUG_HASH_TABLE_SIZE)
return NULL;
return pos;
}
static void pr_debug_seq_stop(struct seq_file *s, void *v)
{
/* Nothing to do */
}
static int pr_debug_seq_show(struct seq_file *s, void *v)
{
struct hlist_head *head;
struct hlist_node *node;
struct debug_name *elem;
unsigned int i = *(loff_t *) v;
rcu_read_lock();
head = &module_table[i];
hlist_for_each_entry_rcu(elem, node, head, hlist) {
seq_printf(s, "%s enabled=%d", elem->name, elem->enable);
seq_printf(s, "\n");
}
rcu_read_unlock();
return 0;
}
static struct seq_operations pr_debug_seq_ops = {
.start = pr_debug_seq_start,
.next = pr_debug_seq_next,
.stop = pr_debug_seq_stop,
.show = pr_debug_seq_show
};
static int pr_debug_open(struct inode *inode, struct file *filp)
{
return seq_open(filp, &pr_debug_seq_ops);
}
static const struct file_operations pr_debug_operations = {
.open = pr_debug_open,
.read = seq_read,
.write = pr_debug_write,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init dynamic_printk_init(void)
{
struct dentry *dir, *file;
struct mod_debug *iter;
unsigned long value;
dir = debugfs_create_dir("dynamic_printk", NULL);
if (!dir)
return -ENOMEM;
file = debugfs_create_file("modules", 0644, dir, NULL,
&pr_debug_operations);
if (!file) {
debugfs_remove(dir);
return -ENOMEM;
}
for (value = (unsigned long)__start___verbose;
value < (unsigned long)__stop___verbose;
value += sizeof(struct mod_debug)) {
iter = (struct mod_debug *)value;
register_dynamic_debug_module(iter->modname,
iter->type,
iter->logical_modname,
iter->flag_names, iter->hash, iter->hash2);
}
return 0;
}
module_init(dynamic_printk_init);
/* may want to move this earlier so we can get traces as early as possible */
static int __init dynamic_printk_setup(char *str)
{
if (str)
return -ENOENT;
set_all(true);
return 0;
}
/* Use early_param(), so we can get debug output as early as possible */
early_param("dynamic_printk", dynamic_printk_setup);

2
net/netfilter/nf_conntrack_pptp.c
View File

@ -65,7 +65,7 @@ void
struct nf_conntrack_expect *exp) __read_mostly;
EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_expectfn);
#ifdef DEBUG
#if defined(DEBUG) || defined(CONFIG_DYNAMIC_PRINTK_DEBUG)
/* PptpControlMessageType names */
const char *const pptp_msg_name[] = {
"UNKNOWN_MESSAGE",

11
scripts/Makefile.lib
View File

@ -96,6 +96,14 @@ basename_flags = -D"KBUILD_BASENAME=KBUILD_STR($(call name-fix,$(basetarget)))"
modname_flags = $(if $(filter 1,$(words $(modname))),\
-D"KBUILD_MODNAME=KBUILD_STR($(call name-fix,$(modname)))")
#hash values
ifdef CONFIG_DYNAMIC_PRINTK_DEBUG
debug_flags = -D"DEBUG_HASH=$(shell ./scripts/basic/hash djb2 $(@D)$(modname))"\
-D"DEBUG_HASH2=$(shell ./scripts/basic/hash r5 $(@D)$(modname))"
else
debug_flags =
endif
orig_c_flags = $(KBUILD_CFLAGS) $(ccflags-y) $(CFLAGS_$(basetarget).o)
_c_flags = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags))
_a_flags = $(KBUILD_AFLAGS) $(asflags-y) $(AFLAGS_$(basetarget).o)
@ -121,7 +129,8 @@ endif
c_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(KBUILD_CPPFLAGS) \
$(__c_flags) $(modkern_cflags) \
-D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags)
-D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags) \
$(debug_flags)
a_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(KBUILD_CPPFLAGS) \
$(__a_flags) $(modkern_aflags)

2
scripts/basic/Makefile
View File

@ -9,7 +9,7 @@
# fixdep: Used to generate dependency information during build process
# docproc: Used in Documentation/DocBook
hostprogs-y := fixdep docproc
hostprogs-y := fixdep docproc hash
always := $(hostprogs-y)
# fixdep is needed to compile other host programs

64
scripts/basic/hash.c Normal file
View File

@ -0,0 +1,64 @@
/*
* Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com>
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define DYNAMIC_DEBUG_HASH_BITS 6
static const char *program;
static void usage(void)
{
printf("Usage: %s <djb2|r5> <modname>\n", program);
exit(1);
}
/* djb2 hashing algorithm by Dan Bernstein. From:
* http://www.cse.yorku.ca/~oz/hash.html
*/
unsigned int djb2_hash(char *str)
{
unsigned long hash = 5381;
int c;
c = *str;
while (c) {
hash = ((hash << 5) + hash) + c;
c = *++str;
}
return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1));
}
unsigned int r5_hash(char *str)
{
unsigned long hash = 0;
int c;
c = *str;
while (c) {
hash = (hash + (c << 4) + (c >> 4)) * 11;
c = *++str;
}
return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1));
}
int main(int argc, char *argv[])
{
program = argv[0];
if (argc != 3)
usage();
if (!strcmp(argv[1], "djb2"))
printf("%d\n", djb2_hash(argv[2]));
else if (!strcmp(argv[1], "r5"))
printf("%d\n", r5_hash(argv[2]));
else
usage();
exit(0);
}