Commit ca90fca7 authored by Jim Cromie's avatar Jim Cromie Committed by Greg Kroah-Hartman
Browse files

dyndbg: add class_id to pr_debug callsites 



DRM issues ~10 exclusive categories of debug messages; to represent
this directly in dyndbg, add a new 6-bit field: struct _ddebug.class_id.
This gives us 64 classes, which should be more than enough.

  #> echo 0x012345678 > /sys/module/drm/parameters/debug

All existing callsites are initialized with _DPRINTK_CLASS_DFLT, which
is 2^6-1.  This reserves 0-62 for use in new categorized/class'd
pr_debugs, which fits perfectly with natural enums (ints: 0..N).

Thats done by extending the init macro: DEFINE_DYNAMIC_DEBUG_METADATA()
with _CLS(cls, ...) suffix, and redefing old name using extended name.

Then extend the factory macro callchain with _cls() versions to provide
the callsite.class_id, with old-names passing _DPRINTK_CLASS_DFLT.

This sets us up to create class'd prdebug callsites (class'd callsites
are those with .class_id != _DPRINTK_CLASS_DFLT).

No behavior change.

cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: default avatarJim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20220904214134.408619-13-jim.cromie@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b7b4eebd

include/linux/dynamic_debug.h

+55 −16
Original line number Diff line number Diff line
@@ -6,6 +6,8 @@ 
#include <linux/jump_label.h>

#endif



#include <linux/build_bug.h>



/*

 * An instance of this structure is created in a special

 * ELF section at every dynamic debug callsite.  At runtime,
@@ -21,6 +23,9 @@ struct _ddebug { 
	const char *filename;

	const char *format;

	unsigned int lineno:18;

#define CLS_BITS 6

	unsigned int class_id:CLS_BITS;

#define _DPRINTK_CLASS_DFLT		((1 << CLS_BITS) - 1)

	/*

	 * The flags field controls the behaviour at the callsite.

	 * The bits here are changed dynamically when the user
@@ -88,7 +93,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, 
			 const struct ib_device *ibdev,

			 const char *fmt, ...);



#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)		\

#define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt)	\

	static struct _ddebug  __aligned(8)			\

	__section("__dyndbg") name = {				\

		.modname = KBUILD_MODNAME,			\
@@ -97,8 +102,14 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, 
		.format = (fmt),				\

		.lineno = __LINE__,				\

		.flags = _DPRINTK_FLAGS_DEFAULT,		\

		.class_id = cls,				\

		_DPRINTK_KEY_INIT				\

	}

	};							\

	BUILD_BUG_ON_MSG(cls > _DPRINTK_CLASS_DFLT,		\

			 "classid value overflow")



#define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)		\

	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, _DPRINTK_CLASS_DFLT, fmt)



#ifdef CONFIG_JUMP_LABEL
@@ -129,17 +140,34 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, 


#endif /* CONFIG_JUMP_LABEL */



#define __dynamic_func_call(id, fmt, func, ...) do {	\

	DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt);		\

/*

 * Factory macros: ($prefix)dynamic_func_call($suffix)

 *

 * Lower layer (with __ prefix) gets the callsite metadata, and wraps

 * the func inside a debug-branch/static-key construct.  Upper layer

 * (with _ prefix) does the UNIQUE_ID once, so that lower can ref the

 * name/label multiple times, and tie the elements together.

 * Multiple flavors:

 * (|_cls):	adds in _DPRINT_CLASS_DFLT as needed

 * (|_no_desc):	former gets callsite descriptor as 1st arg (for prdbgs)

 */

#define __dynamic_func_call_cls(id, cls, fmt, func, ...) do {	\

	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);	\

	if (DYNAMIC_DEBUG_BRANCH(id))				\

		func(&id, ##__VA_ARGS__);			\

} while (0)

#define __dynamic_func_call(id, fmt, func, ...)				\

	__dynamic_func_call_cls(id, _DPRINTK_CLASS_DFLT, fmt,		\

				func, ##__VA_ARGS__)



#define __dynamic_func_call_no_desc(id, fmt, func, ...) do {	\

	DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt);			\

#define __dynamic_func_call_cls_no_desc(id, cls, fmt, func, ...) do {	\

	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);		\

	if (DYNAMIC_DEBUG_BRANCH(id))					\

		func(__VA_ARGS__);					\

} while (0)

#define __dynamic_func_call_no_desc(id, fmt, func, ...)			\

	__dynamic_func_call_cls_no_desc(id, _DPRINTK_CLASS_DFLT,	\

					fmt, func, ##__VA_ARGS__)



/*

 * "Factory macro" for generating a call to func, guarded by a
@@ -149,15 +177,26 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, 
 * the varargs. Note that fmt is repeated in invocations of this

 * macro.

 */

#define _dynamic_func_call_cls(cls, fmt, func, ...)			\

	__dynamic_func_call_cls(__UNIQUE_ID(ddebug), cls, fmt, func, ##__VA_ARGS__)

#define _dynamic_func_call(fmt, func, ...)				\

	__dynamic_func_call(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)

	_dynamic_func_call_cls(_DPRINTK_CLASS_DFLT, fmt, func, ##__VA_ARGS__)



/*

 * A variant that does the same, except that the descriptor is not

 * passed as the first argument to the function; it is only called

 * with precisely the macro's varargs.

 */

#define _dynamic_func_call_cls_no_desc(cls, fmt, func, ...)		\

	__dynamic_func_call_cls_no_desc(__UNIQUE_ID(ddebug), cls, fmt,	\

					func, ##__VA_ARGS__)

#define _dynamic_func_call_no_desc(fmt, func, ...)			\

	__dynamic_func_call_no_desc(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)

	_dynamic_func_call_cls_no_desc(_DPRINTK_CLASS_DFLT, fmt,	\

				       func, ##__VA_ARGS__)



#define dynamic_pr_debug_cls(cls, fmt, ...)				\

	_dynamic_func_call_cls(cls, fmt, __dynamic_pr_debug,		\

			   pr_fmt(fmt), ##__VA_ARGS__)



#define dynamic_pr_debug(fmt, ...)				\

	_dynamic_func_call(fmt, __dynamic_pr_debug,		\