The patch titled
Subject: dynamic_debug: add an option to enable dynamic debug for modules only
has been added to the -mm tree. Its filename is
dynamic_debug-add-an-option-to-enable-dynamic-debug-for-modules-only.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/dynamic_debug-add-an-option-to-enable-dynamic-debug-for-modules-only.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/dynamic_debug-add-an-option-to-enable-dynamic-debug-for-modules-only.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Orson Zhai <orson.zhai@xxxxxxxxxx>
Subject: dynamic_debug: add an option to enable dynamic debug for modules only
Instead of enabling dynamic debug globally with CONFIG_DYNAMIC_DEBUG,
CONFIG_DYNAMIC_DEBUG_CORE will only enable core function of dynamic debug.
With the DEBUG_MODULE defined for any modules, dynamic debug will be tied
to them.
This is useful for people who only want to enable dynamic debug for kernel
modules without worrying about kernel image size and memory consumption
increasing too much.
Link: http://lkml.kernel.org/r/1586521984-5890-1-git-send-email-orson.unisoc@xxxxxxxxx
Signed-off-by: Orson Zhai <orson.zhai@xxxxxxxxxx>
Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Jason Baron <jbaron@xxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/dynamic-debug-howto.rst | 7 ++++--
include/linux/dev_printk.h | 6 +++--
include/linux/dynamic_debug.h | 2 -
include/linux/printk.h | 14 +++++++-----
lib/Kconfig.debug | 12 ++++++++++
lib/Makefile | 2 -
lib/dynamic_debug.c | 9 ++++++-
7 files changed, 39 insertions(+), 13 deletions(-)
--- a/Documentation/admin-guide/dynamic-debug-howto.rst~dynamic_debug-add-an-option-to-enable-dynamic-debug-for-modules-only
+++ a/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -13,8 +13,11 @@ kernel code to obtain additional kernel
``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically
enabled per-callsite.
-If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just
-shortcut for ``print_hex_dump(KERN_DEBUG)``.
+If ``CONFIG_DYNAMIC_DEBUG_CORE`` is set, only the modules with ``DEBUG_MODULE``
+defined will be tied into dynamic debug.
+
+If ``CONFIG_DYNAMIC_DEBUG`` or ``CONFIG_DYNAMIC_DEBUG_CORE`` is not set,
+``print_hex_dump_debug()`` is just shortcut for ``print_hex_dump(KERN_DEBUG)``.
For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
its ``prefix_str`` argument, if it is constant string; or ``hexdump``
--- a/include/linux/dev_printk.h~dynamic_debug-add-an-option-to-enable-dynamic-debug-for-modules-only
+++ a/include/linux/dev_printk.h
@@ -109,7 +109,8 @@ void _dev_info(const struct device *dev,
#define dev_info(dev, fmt, ...) \
_dev_info(dev, dev_fmt(fmt), ##__VA_ARGS__)
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DEBUG_MODULE))
#define dev_dbg(dev, fmt, ...) \
dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
#elif defined(DEBUG)
@@ -181,7 +182,8 @@ do { \
dev_level_ratelimited(dev_notice, dev, fmt, ##__VA_ARGS__)
#define dev_info_ratelimited(dev, fmt, ...) \
dev_level_ratelimited(dev_info, dev, fmt, ##__VA_ARGS__)
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DEBUG_MODULE))
/* descriptor check is first to prevent flooding with "callbacks suppressed" */
#define dev_dbg_ratelimited(dev, fmt, ...) \
do { \
--- a/include/linux/dynamic_debug.h~dynamic_debug-add-an-option-to-enable-dynamic-debug-for-modules-only
+++ a/include/linux/dynamic_debug.h
@@ -48,7 +48,7 @@ struct _ddebug {
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
int ddebug_add_module(struct _ddebug *tab, unsigned int n,
const char *modname);
extern int ddebug_remove_module(const char *mod_name);
--- a/include/linux/printk.h~dynamic_debug-add-an-option-to-enable-dynamic-debug-for-modules-only
+++ a/include/linux/printk.h
@@ -286,8 +286,9 @@ extern int kptr_restrict;
/*
* These can be used to print at the various log levels.
* All of these will print unconditionally, although note that pr_debug()
- * and other debug macros are compiled out unless either DEBUG is defined
- * or CONFIG_DYNAMIC_DEBUG is set.
+ * and other debug macros are compiled out unless either DEBUG is defined,
+ * CONFIG_DYNAMIC_DEBUG is set, or CONFIG_DYNAMIC_DEBUG_CORE is set when
+ * DEBUG_MODULE being defined for any modules.
*/
#define pr_emerg(fmt, ...) \
printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
@@ -322,7 +323,8 @@ extern int kptr_restrict;
/* If you are writing a driver, please use dev_dbg instead */
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DEBUG_MODULE))
#include <linux/dynamic_debug.h>
/* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
@@ -448,7 +450,8 @@ extern int kptr_restrict;
#endif
/* If you are writing a driver, please use dev_dbg instead */
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DEBUG_MODULE))
/* descriptor check is first to prevent flooding with "callbacks suppressed" */
#define pr_debug_ratelimited(fmt, ...) \
do { \
@@ -495,7 +498,8 @@ static inline void print_hex_dump_bytes(
#endif
-#if defined(CONFIG_DYNAMIC_DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG) || \
+ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DEBUG_MODULE))
#define print_hex_dump_debug(prefix_str, prefix_type, rowsize, \
groupsize, buf, len, ascii) \
dynamic_hex_dump(prefix_str, prefix_type, rowsize, \
--- a/lib/dynamic_debug.c~dynamic_debug-add-an-option-to-enable-dynamic-debug-for-modules-only
+++ a/lib/dynamic_debug.c
@@ -1032,8 +1032,13 @@ static int __init dynamic_debug_init(voi
int verbose_bytes = 0;
if (&__start___verbose == &__stop___verbose) {
- pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
- return 1;
+ if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
+ pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
+ return 1;
+ }
+ pr_info("Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build\n");
+ ddebug_init_success = 1;
+ return 0;
}
iter = __start___verbose;
modname = iter->modname;
--- a/lib/Kconfig.debug~dynamic_debug-add-an-option-to-enable-dynamic-debug-for-modules-only
+++ a/lib/Kconfig.debug
@@ -99,6 +99,7 @@ config DYNAMIC_DEBUG
default n
depends on PRINTK
depends on (DEBUG_FS || PROC_FS)
+ select DYNAMIC_DEBUG_CORE
help
Compiles debug level messages into the kernel, which would not
@@ -165,6 +166,17 @@ config DYNAMIC_DEBUG
See Documentation/admin-guide/dynamic-debug-howto.rst for additional
information.
+config DYNAMIC_DEBUG_CORE
+ bool "Enable core function of dynamic debug support"
+ depends on PRINTK
+ depends on (DEBUG_FS || PROC_FS)
+ help
+ Enable core functional support of dynamic debug. It is useful
+ when you want to tie dynamic debug to your kernel modules with
+ DEBUG_MODULE defined for each of them, especially for the case
+ of embedded system where the kernel image size is sensitive for
+ people.
+
config SYMBOLIC_ERRNAME
bool "Support symbolic error names in printf"
default y if PRINTK
--- a/lib/Makefile~dynamic_debug-add-an-option-to-enable-dynamic-debug-for-modules-only
+++ a/lib/Makefile
@@ -186,7 +186,7 @@ lib-$(CONFIG_GENERIC_BUG) += bug.o
obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
-obj-$(CONFIG_DYNAMIC_DEBUG) += dynamic_debug.o
+obj-$(CONFIG_DYNAMIC_DEBUG_CORE) += dynamic_debug.o
obj-$(CONFIG_SYMBOLIC_ERRNAME) += errname.o
obj-$(CONFIG_NLATTR) += nlattr.o
_
Patches currently in -mm which might be from orson.zhai@xxxxxxxxxx are
dynamic_debug-add-an-option-to-enable-dynamic-debug-for-modules-only.patch
