Messages in this thread | | | Subject | Re: [RFC PATCH] dynamic_debug: Add config option of DYNAMIC_DEBUG_CORE | From | Jason Baron <> | Date | Wed, 18 Mar 2020 17:18:43 -0400 |
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On 3/18/20 3:03 PM, Orson Zhai wrote: > There is the requirement from new Android that kernel image (GKI) and > kernel modules are supposed to be built at differnet places. Some people > want to enable dynamic debug for kernel modules only but not for kernel > image itself with the consideration of binary size increased or more > memory being used. > > By this patch, dynamic debug is divided into core part (the defination of > functions) and macro replacement part. We can only have the core part to > be built-in and do not have to activate the debug output from kenrel image. > > Signed-off-by: Orson Zhai <orson.unisoc@gmail.com>
Hi Orson,
I think this is a nice feature. Is the idea then that driver can do something like:
#if defined(CONFIG_DRIVER_FOO_DEBUG) #define driver_foo_debug(fmt, ...) \ dynamic_pr_debug(fmt, ##__VA_ARGS__) #else no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__) #enif
And then the Kconfig:
config DYNAMIC_DRIVER_FOO_DEBUG bool "Enable dynamic driver foo printk() support" select DYNAMIC_DEBUG_CORE
Or did you have something else in mind? Do you have an example code for the drivers that you mention?
Thanks,
-Jason
> --- > include/linux/dynamic_debug.h | 2 +- > lib/Kconfig.debug | 18 ++++++++++++++++-- > lib/Makefile | 2 +- > 3 files changed, 18 insertions(+), 4 deletions(-) > > diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h > index 4cf02ec..abcd5fd 100644 > --- a/include/linux/dynamic_debug.h > +++ b/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); > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 69def4a..78a7256 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -97,8 +97,7 @@ config BOOT_PRINTK_DELAY > config DYNAMIC_DEBUG > bool "Enable dynamic printk() support" > default n > - depends on PRINTK > - depends on DEBUG_FS > + select DYNAMIC_DEBUG_CORE > help > > Compiles debug level messages into the kernel, which would not > @@ -164,6 +163,21 @@ config DYNAMIC_DEBUG > See Documentation/admin-guide/dynamic-debug-howto.rst for additional > information. > > +config DYNAMIC_DEBUG_CORE > + bool "Enable core functions of dynamic debug support" > + depends on PRINTK > + depends on DEBUG_FS > + help > + Enable this option to build ddebug_* and __dynamic_* routines > + into kernel. If you want enable whole dynamic debug features, > + select CONFIG_DYNAMIC_DEBUG directly and this option will be > + automatically selected. > + > + This option is selected when you want to enable dynamic debug > + for kernel modules only but not for the kernel base. Especailly > + in the case that kernel modules are built out of the place where > + kernel base is built. > + > config SYMBOLIC_ERRNAME > bool "Support symbolic error names in printf" > default y if PRINTK > diff --git a/lib/Makefile b/lib/Makefile > index 611872c..2096d83 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -183,7 +183,7 @@ 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 >
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