[PATCH v6 00/24] fix dynamic-debug classmaps API for DRM

[PATCH v6 00/24] fix dynamic-debug classmaps API for DRM

[Jim Cromie]

This series fixes problems which broke CONFIG_DRM_USE_DYNAMIC_DEBUG=Y.

1st chunk fixes a section misalignement on i386, when CONFIG_DRM=y and
CONFIG_DRM_USE_DYNAMIC_DEBUG=Y.  It also repairs a linkage failure
where the dyndbg sections got dropped from loadable modules in some
arches.  This chunk was reviewed by Petr Pavlu (thx).

2nd chunk is a set of cleanups, callchain refactors, struct refactors,
and internal reorgs in preparation for the API change needed to fix
the regression seen in DRM where boot-time drm.debug settings (in
core) did not propagate to drivers.

3rd is the API change itself; replacing DECLARE_DYNDBG_CLASSMAP (used
in both core and drivers, a K&R define-once-use-thereafter violation,
which caused the regression) with DYNAMIC_DEBUG_CLASSMAP_DEFINE in
core, and $1_USE in drivers and helpers.

There are 2 user-visible changes:

1. change an ERROR condition displayed in dynamic_debug/control,
from "class:unknown, _id:1" to "class:_UNKNOWN_ id:1"

This only happens if a classmap is incorrectly defined, so it should
not pass review, and should be SHOUTED about.  And since classmaps are
BROKEN for DRM (its only user), this affects no users.

2. change builtin module names, displayed in dynamic_debug/control,
from simple "[main]" to subsystem "[init/main]" etc.  This corrects an
existing naming ambiguity, which is disallowed for loadable modules by
the module loader.  To preserve legacy query behavior, "module main"
will select all of "[*/main]".

NB: the current ambiguity prevents cleanly adding classmaps to
builtins named "[main]".  Such an addition is quite unlikely, so this
change could be dropped, but it seemed proper to correct it and point
it out.

3. revert a change in classmaps-v1 (2022) which enlarged __drm_debug
from (unsigned) int to long int.  64 categories of drm-debug is well
past reasonable, the param is now a u32, for clarity.

---
this is based on v7.2-rc2
Ive trimmed the cc-list to stay under gmail's 500msgs/day

Changes in v6:

previous versions split the 1st chunk into a separate submission, in
an attempt to get past gmail's 500 msgs/day limit, and to ease review.

This complicated application; although the 2nd chunk had the b4
dependency on the 1st, this fact was missed by sashiko, which
therefore couldnt apply it.

A followon series adds compile-time and runtime checks to fail-fast if
classmaps are used incorrectly.

Changes in v5:

move KBUILD_MODFILE ahead of array-slice, to address sashiko
complaints which were fixed by later patches in V4.

Changes in v4:

Dyndbg previously used KBUILD_MODNAME to provide module-name, this
works well for loadable modules (module loader requires unique module
names), but for builtin modules, is effectively kbasename, and is not
guaranteed unique.

So we get 4 modules named "main": init/main, kernel/power/main,
kernel/base/power/main.  This ambiguity is visible in user-space since
the beginning of dyndbg.

Now suppose kernel/{,base}/power/main want to define classmaps to
categorize the various pr-debugs they have.  The current code finds a
module's classmaps by strcmp on modname, so init/main will match
against classmaps defined by both kernel/{,base}/power/main.

The current code will also map "main" classes to kernel/*/power/main,
so they will probably work at first, but 2 independent classmaps can
both use class-ids 0-N, but will conflict if they're both used by a
module.  Then we have classmap overlaps and unpredictable results.

v3:
- move #includes to top of files,
- drop redundant ALIGN(8) in dydnbg.lds.S: DYNDBG_SECTIONS macro
- add Reviewed-by tag (thx Petr)

v2:
- avoid BOUNDED_SECTION in modules, dont need _start & _end symbols.
- sets 0 address to the sections, not just whatever current is.

---
Jim Cromie (24):
      vmlinux.lds.h: refactor BOUNDED_SECTION_* macros into bounded_sections.lds.h
      vmlinux.lds.h: drop unused HEADERED_SECTION* macros
      vmlinux.lds.h: Fix ALIGN(8) omission causing NULL ptr on i386
      vmlinux.lds.h: remove redundant ALIGN(8) directives
      dyndbg.lds.S: fix lost dyndbg sections in modules
      dyndbg: factor ddebug_match_desc out from ddebug_change
      dyndbg: add stub macro for DECLARE_DYNDBG_CLASSMAP
      dyndbg: reword "class unknown," to "class:_UNKNOWN_"
      dyndbg-API: remove DD_CLASS_TYPE_(DISJOINT|LEVEL)_NAMES and code
      dyndbg: drop NUM_TYPE_ARGS
      dyndbg: bump num-tokens in a query-cmd from 9 to 15
      dyndbg: reduce verbose/debug clutter
      lib/parser: add match_wildcard_hyphen() for agnostic matching
      dyndbg: use KBUILD_MODFILE for unique builtin module names
      dyndbg: refactor param_set_dyndbg_classes and below
      dyndbg: tighten fn-sig of ddebug_apply_class_bitmap
      dyndbg: replace classmap list with an array-slice
      dyndbg: macrofy a 2-index for-loop pattern
      dyndbg: pin class param storage to u32
      dyndbg,module: make proper substructs in _ddebug_info
      dyndbg: move mod_name down from struct ddebug_table to _ddebug_info
      dyndbg: hoist classmap-filter-by-modname up to ddebug_add_module
      dyndbg: change __dynamic_func_call_cls* macros into expressions
      dyndbg-API: replace DECLARE_DYNDBG_CLASSMAP

 Documentation/admin-guide/dynamic-debug-howto.rst |  42 +-
 MAINTAINERS                                       |   1 +
 drivers/gpu/drm/drm_print.c                       |   6 +-
 include/asm-generic/bounded_sections.lds.h        |  32 ++
 include/asm-generic/dyndbg.lds.h                  |  22 +
 include/asm-generic/vmlinux.lds.h                 |  68 +--
 include/drm/drm_print.h                           |   2 +-
 include/linux/dynamic_debug.h                     | 275 +++++++---
 include/linux/parser.h                            |   1 +
 kernel/module/main.c                              |  15 +-
 lib/Kconfig.debug                                 |  24 +-
 lib/Makefile                                      |   3 +
 lib/dynamic_debug.c                               | 608 +++++++++++++---------
 lib/parser.c                                      |  58 ++-
 lib/test_dynamic_debug.c                          | 145 ++++--
 lib/test_dynamic_debug_submod.c                   |  14 +
 scripts/module.lds.S                              |   2 +
 17 files changed, 846 insertions(+), 472 deletions(-)
---
base-commit: 8cdeaa50eae8dad34885515f62559ee83e7e8dda
change-id: 20260521-dd-maint-2-76c542079420
prerequisite-change-id: 20260630-fix-align-589738662161:v4
prerequisite-patch-id: d6b2b7d254c7e8bbc0aea891d49b15dc1e71eaa4
prerequisite-patch-id: 3dffaa165e78dc58e443469755eddb07972d0ddf
prerequisite-patch-id: 2c4827d84b4159e71df89cca2a03938a534ecdb5
prerequisite-patch-id: 4599f9be1eb06c0d7f2a7c657d4940411635e94b
prerequisite-patch-id: aea9e121b30e3c7f3d76921b49f81ad421b7af51

Best regards,
-- 
Jim Cromie <jim.cromie@gmail.com>

[PATCH v6 01/24] vmlinux.lds.h: refactor BOUNDED_SECTION_* macros into bounded_sections.lds.h

[Jim Cromie]

Move BOUNDED_SECTION_* macros to a new helper file:
include/asm-generic/bounded_sections.lds.h and include it back into
vmlinux.lds.h.  This allows its reuse later to fix a failure to keep
dyndbg sections in some circumstances.

NOTES:

These macros are only for use in vmlinux.lds.h, where the _start &
_end symbols are needed.  Modules keep sections separate in ELF
sections, with their boundaries known, so the _start and _end are not
useful, and may confuse tools not expecting them.

This patch ignores a checkpatch warning, because new file is covered
by "GENERIC INCLUDE/ASM HEADER FILES" in MAINTAINERS

CC: Arnd Bergmann <arnd@arndb.de>
CC: linux-arch@vger.kernel.org
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v3: move include to top
---
 include/asm-generic/bounded_sections.lds.h | 36 ++++++++++++++++++++++++++++++
 include/asm-generic/vmlinux.lds.h          | 31 +------------------------
 2 files changed, 37 insertions(+), 30 deletions(-)

diff --git a/include/asm-generic/bounded_sections.lds.h b/include/asm-generic/bounded_sections.lds.h
new file mode 100644
index 000000000000..8c29293ca7fb
--- /dev/null
+++ b/include/asm-generic/bounded_sections.lds.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _ASM_GENERIC_BOUNDED_SECTIONS_H
+#define _ASM_GENERIC_BOUNDED_SECTIONS_H
+
+#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_)	\
+	_BEGIN_##_label_ = .;						\
+	KEEP(*(_sec_))							\
+	_END_##_label_ = .;
+
+#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_)	\
+	_label_##_BEGIN_ = .;						\
+	KEEP(*(_sec_))							\
+	_label_##_END_ = .;
+
+#define BOUNDED_SECTION_BY(_sec_, _label_)				\
+	BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop)
+
+#define BOUNDED_SECTION(_sec)	 BOUNDED_SECTION_BY(_sec, _sec)
+
+#define HEADERED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
+	_HDR_##_label_	= .;						\
+	KEEP(*(.gnu.linkonce.##_sec_))					\
+	BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_)
+
+#define HEADERED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
+	_label_##_HDR_ = .;						\
+	KEEP(*(.gnu.linkonce.##_sec_))					\
+	BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_)
+
+#define HEADERED_SECTION_BY(_sec_, _label_)				\
+	HEADERED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop)
+
+#define HEADERED_SECTION(_sec)	 HEADERED_SECTION_BY(_sec, _sec)
+
+#endif /* _ASM_GENERIC_BOUNDED_SECTIONS_H */
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 5659f4b5a125..f5ddf31b7f26 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -50,6 +50,7 @@
  *               [__nosave_begin, __nosave_end] for the nosave data
  */
 
+#include <asm-generic/bounded_sections.lds.h>
 #include <asm-generic/codetag.lds.h>
 
 #ifndef LOAD_OFFSET
@@ -211,36 +212,6 @@
 # endif
 #endif
 
-#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_)	\
-	_BEGIN_##_label_ = .;						\
-	KEEP(*(_sec_))							\
-	_END_##_label_ = .;
-
-#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_)	\
-	_label_##_BEGIN_ = .;						\
-	KEEP(*(_sec_))							\
-	_label_##_END_ = .;
-
-#define BOUNDED_SECTION_BY(_sec_, _label_)				\
-	BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop)
-
-#define BOUNDED_SECTION(_sec)	 BOUNDED_SECTION_BY(_sec, _sec)
-
-#define HEADERED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
-	_HDR_##_label_	= .;						\
-	KEEP(*(.gnu.linkonce.##_sec_))					\
-	BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_)
-
-#define HEADERED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
-	_label_##_HDR_ = .;						\
-	KEEP(*(.gnu.linkonce.##_sec_))					\
-	BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_)
-
-#define HEADERED_SECTION_BY(_sec_, _label_)				\
-	HEADERED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop)
-
-#define HEADERED_SECTION(_sec)	 HEADERED_SECTION_BY(_sec, _sec)
-
 #ifdef CONFIG_TRACE_BRANCH_PROFILING
 #define LIKELY_PROFILE()						\
 	BOUNDED_SECTION_BY(_ftrace_annotated_branch, _annotated_branch_profile)

-- 
2.55.0

[PATCH v6 02/24] vmlinux.lds.h: drop unused HEADERED_SECTION* macros

[Jim Cromie]

These macros are unused, no point in carrying them any more.

NB: these macros were just moved to bounded_sections.lds.h, from
vmlinux.lds.h, which is the known entity, and therefore more
meaningful in the 1-line summary, so thats what I used as the topic.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/asm-generic/bounded_sections.lds.h | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/include/asm-generic/bounded_sections.lds.h b/include/asm-generic/bounded_sections.lds.h
index 8c29293ca7fb..268cdc34389b 100644
--- a/include/asm-generic/bounded_sections.lds.h
+++ b/include/asm-generic/bounded_sections.lds.h
@@ -18,19 +18,4 @@
 
 #define BOUNDED_SECTION(_sec)	 BOUNDED_SECTION_BY(_sec, _sec)
 
-#define HEADERED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
-	_HDR_##_label_	= .;						\
-	KEEP(*(.gnu.linkonce.##_sec_))					\
-	BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_)
-
-#define HEADERED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_, _HDR_) \
-	_label_##_HDR_ = .;						\
-	KEEP(*(.gnu.linkonce.##_sec_))					\
-	BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_)
-
-#define HEADERED_SECTION_BY(_sec_, _label_)				\
-	HEADERED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop)
-
-#define HEADERED_SECTION(_sec)	 HEADERED_SECTION_BY(_sec, _sec)
-
 #endif /* _ASM_GENERIC_BOUNDED_SECTIONS_H */

-- 
2.55.0

[PATCH v6 03/24] vmlinux.lds.h: Fix ALIGN(8) omission causing NULL ptr on i386

[Jim Cromie]

Almost all uses of the BOUNDED_SECTION macros are ALIGN(8), either
explicitly, or by being below an aligned section containing x*8 byte
objects.  The noteworthy exception is BOUNDED_SECTION(__dyndbg), which
immediately follows BOUNDED_SECTION(__dyndbg_classes).

On i386, struct _ddebug_classmap is 28 bytes, so without an explicit
ALIGN(8) in the macro, the following __dyndbg section gets misaligned,
causing a NULL ptr deref in dynamic_debug_init().

So fix this with an explicit ALIGN(8) in the existing BOUNDED_SECTION
macros, and introduce _ALIGNED variants to handle the cases with an
explicit . = ALIGN(x)

Also add explicit alignments for: EXCEPTION_TABLE, ORC_UNWIND_TABLE,
TRACEDATA, INIT_SETUP, and NOTES.

update BOUNDED_SECTION uses inside . = ALIGN(x) stanzas to use
_ALIGNED variants, but keep the outer ALIGNs so the symbols between
them are not "re-aligned".

In particular, scripts/sorttable.c does not tolerate sloppy padding.

At the top of ORC_UNWIND_TABLE, add . = ALIGN(4) to match the struct
orc_header __align() call in the code:

commit b9f174c811e3 ("x86/unwind/orc: Add ELF section with ORC version identifier")

Suggested-by: Louis Chauvet <louis.chauvet@bootlin.com>  # _ALIGNED variants.
Link: https://lore.kernel.org/lkml/177402491426.6181.12855763650074831089.b4-review@b4/
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v3:

sashiko complained about NOTES and .BTF_ids.
gemini asserts that NOTES are natively 4-byte aligned, add comment repeating it.
.BTF_ids doesnt use BOUNDED_BY, since start/end isnt needed;
sashiko evidently got confused by immediately preceding usage.

v2:

sashiko picked up 2 cases, added to the explicit list above
https://sashiko.dev/#/patchset/20260515-asm-generic-1-v3-0-680b273666d4%40gmail.com
---
 include/asm-generic/bounded_sections.lds.h | 17 ++++++++++++++---
 include/asm-generic/vmlinux.lds.h          | 18 ++++++++++--------
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/include/asm-generic/bounded_sections.lds.h b/include/asm-generic/bounded_sections.lds.h
index 268cdc34389b..8ff3e3420f60 100644
--- a/include/asm-generic/bounded_sections.lds.h
+++ b/include/asm-generic/bounded_sections.lds.h
@@ -3,19 +3,30 @@
 #ifndef _ASM_GENERIC_BOUNDED_SECTIONS_H
 #define _ASM_GENERIC_BOUNDED_SECTIONS_H
 
-#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_)	\
+#define BOUNDED_SECTION_PRE_LABEL_ALIGNED(_sec_, _label_, _BEGIN_, _END_, _ALIGNED_) \
+	. = ALIGN(_ALIGNED_);						\
 	_BEGIN_##_label_ = .;						\
 	KEEP(*(_sec_))							\
 	_END_##_label_ = .;
 
-#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_)	\
+#define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _BEGIN_, _END_)	\
+	BOUNDED_SECTION_PRE_LABEL_ALIGNED(_sec_, _label_, _BEGIN_, _END_, 8)
+
+#define BOUNDED_SECTION_POST_LABEL_ALIGNED(_sec_, _label_, _BEGIN_, _END_, _ALIGNED_) \
+	. = ALIGN(_ALIGNED_);						\
 	_label_##_BEGIN_ = .;						\
 	KEEP(*(_sec_))							\
 	_label_##_END_ = .;
 
+#define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _BEGIN_, _END_)	\
+	BOUNDED_SECTION_POST_LABEL_ALIGNED(_sec_, _label_, _BEGIN_, _END_, 8)
+
 #define BOUNDED_SECTION_BY(_sec_, _label_)				\
 	BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, __start, __stop)
 
-#define BOUNDED_SECTION(_sec)	 BOUNDED_SECTION_BY(_sec, _sec)
+#define BOUNDED_SECTION_BY_ALIGNED(_sec_, _label_, _ALIGNED_)		\
+	BOUNDED_SECTION_PRE_LABEL_ALIGNED(_sec_, _label_, __start, __stop, _ALIGNED_)
+
+#define BOUNDED_SECTION(_sec)   BOUNDED_SECTION_BY(_sec, _sec)
 
 #endif /* _ASM_GENERIC_BOUNDED_SECTIONS_H */
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index f5ddf31b7f26..f29fc079e37e 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -640,7 +640,7 @@
 #define EXCEPTION_TABLE(align)						\
 	. = ALIGN(align);						\
 	__ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {		\
-		BOUNDED_SECTION_BY(__ex_table, ___ex_table)		\
+		BOUNDED_SECTION_BY_ALIGNED(__ex_table, ___ex_table, align) \
 	}
 
 /*
@@ -650,7 +650,7 @@
 #define BTF								\
 	. = ALIGN(PAGE_SIZE);						\
 	.BTF : AT(ADDR(.BTF) - LOAD_OFFSET) {				\
-		BOUNDED_SECTION_BY(.BTF, _BTF)				\
+		BOUNDED_SECTION_BY_ALIGNED(.BTF, _BTF, PAGE_SIZE)	\
 	}								\
 	. = ALIGN(PAGE_SIZE);						\
 	.BTF_ids : AT(ADDR(.BTF_ids) - LOAD_OFFSET) {			\
@@ -832,16 +832,17 @@
 
 #ifdef CONFIG_UNWINDER_ORC
 #define ORC_UNWIND_TABLE						\
+	. = ALIGN(4);							\
 	.orc_header : AT(ADDR(.orc_header) - LOAD_OFFSET) {		\
-		BOUNDED_SECTION_BY(.orc_header, _orc_header)		\
+		BOUNDED_SECTION_BY_ALIGNED(.orc_header, _orc_header, 4)	\
 	}								\
 	. = ALIGN(4);							\
 	.orc_unwind_ip : AT(ADDR(.orc_unwind_ip) - LOAD_OFFSET) {	\
-		BOUNDED_SECTION_BY(.orc_unwind_ip, _orc_unwind_ip)	\
+		BOUNDED_SECTION_BY_ALIGNED(.orc_unwind_ip, _orc_unwind_ip, 4)\
 	}								\
 	. = ALIGN(2);							\
 	.orc_unwind : AT(ADDR(.orc_unwind) - LOAD_OFFSET) {		\
-		BOUNDED_SECTION_BY(.orc_unwind, _orc_unwind)		\
+		BOUNDED_SECTION_BY_ALIGNED(.orc_unwind, _orc_unwind, 2)	\
 	}								\
 	text_size = _etext - _stext;					\
 	. = ALIGN(4);							\
@@ -869,7 +870,7 @@
 #define TRACEDATA							\
 	. = ALIGN(4);							\
 	.tracedata : AT(ADDR(.tracedata) - LOAD_OFFSET) {		\
-		BOUNDED_SECTION_POST_LABEL(.tracedata, __tracedata, _start, _end) \
+		BOUNDED_SECTION_POST_LABEL_ALIGNED(.tracedata, __tracedata, _start, _end, 4) \
 	}
 #else
 #define TRACEDATA
@@ -898,13 +899,14 @@
 		*(.note.gnu.property)					\
 	}								\
 	.notes : AT(ADDR(.notes) - LOAD_OFFSET) {			\
-		BOUNDED_SECTION_BY(.note.*, _notes)			\
+		/* *(.note.*) are natively 4-byte aligned */		\
+		BOUNDED_SECTION_BY_ALIGNED(.note.*, _notes, 4)		\
 	} NOTES_HEADERS							\
 	NOTES_HEADERS_RESTORE
 
 #define INIT_SETUP(initsetup_align)					\
 		. = ALIGN(initsetup_align);				\
-		BOUNDED_SECTION_POST_LABEL(.init.setup, __setup, _start, _end)
+		BOUNDED_SECTION_POST_LABEL_ALIGNED(.init.setup, __setup, _start, _end, initsetup_align)
 
 #define INIT_CALLS_LEVEL(level)						\
 		__initcall##level##_start = .;				\

-- 
2.55.0

[PATCH v6 04/24] vmlinux.lds.h: remove redundant ALIGN(8) directives

[Jim Cromie]

The BOUNDED_SECTION_PRE_LABEL and BOUNDED_SECTION_POST_LABEL macros
were recently updated to inherently enforce an 8-byte alignment. This
makes the explicit '. = ALIGN(8);' statements preceding 'naked' macro
calls in vmlinux.lds.h redundant.

Remove these redundant alignment directives to clean up the file and
clarify that the macros handle their own alignment padding.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/asm-generic/vmlinux.lds.h | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index f29fc079e37e..3758a79d0430 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -228,7 +228,6 @@
 
 #ifdef CONFIG_KPROBES
 #define KPROBE_BLACKLIST()				\
-	. = ALIGN(8);					\
 	BOUNDED_SECTION(_kprobe_blacklist)
 #else
 #define KPROBE_BLACKLIST()
@@ -244,7 +243,6 @@
 
 #ifdef CONFIG_EVENT_TRACING
 #define FTRACE_EVENTS()							\
-	. = ALIGN(8);							\
 	BOUNDED_SECTION(_ftrace_events)					\
 	BOUNDED_SECTION_BY(_ftrace_eval_map, _ftrace_eval_maps)
 #else
@@ -261,7 +259,6 @@
 
 #ifdef CONFIG_FTRACE_SYSCALLS
 #define TRACE_SYSCALLS()			\
-	. = ALIGN(8);				\
 	BOUNDED_SECTION_BY(__syscalls_metadata, _syscalls_metadata)
 #else
 #define TRACE_SYSCALLS()
@@ -276,7 +273,6 @@
 
 #ifdef CONFIG_SERIAL_EARLYCON
 #define EARLYCON_TABLE()						\
-	. = ALIGN(8);							\
 	BOUNDED_SECTION_POST_LABEL(__earlycon_table, __earlycon_table, , _end)
 #else
 #define EARLYCON_TABLE()
@@ -284,11 +280,9 @@
 
 #ifdef CONFIG_SECURITY
 #define LSM_TABLE()					\
-	. = ALIGN(8);					\
 	BOUNDED_SECTION_PRE_LABEL(.lsm_info.init, _lsm_info, __start, __end)
 
 #define EARLY_LSM_TABLE()						\
-	. = ALIGN(8);							\
 	BOUNDED_SECTION_PRE_LABEL(.early_lsm_info.init, _early_lsm_info, __start, __end)
 #else
 #define LSM_TABLE()
@@ -314,7 +308,6 @@
 
 #ifdef CONFIG_ACPI
 #define ACPI_PROBE_TABLE(name)						\
-	. = ALIGN(8);							\
 	BOUNDED_SECTION_POST_LABEL(__##name##_acpi_probe_table,		\
 				   __##name##_acpi_probe_table,, _end)
 #else
@@ -323,7 +316,6 @@
 
 #ifdef CONFIG_THERMAL
 #define THERMAL_TABLE(name)						\
-	. = ALIGN(8);							\
 	BOUNDED_SECTION_POST_LABEL(__##name##_thermal_table,		\
 				   __##name##_thermal_table,, _end)
 #else
@@ -403,12 +395,10 @@
 	__end_init_stack = .;
 
 #define JUMP_TABLE_DATA							\
-	. = ALIGN(8);							\
 	BOUNDED_SECTION_BY(__jump_table, ___jump_table)
 
 #ifdef CONFIG_HAVE_STATIC_CALL_INLINE
 #define STATIC_CALL_DATA						\
-	. = ALIGN(8);							\
 	BOUNDED_SECTION_BY(.static_call_sites, _static_call_sites)	\
 	BOUNDED_SECTION_BY(.static_call_tramp_key, _static_call_tramp_key)
 #else
@@ -453,7 +443,6 @@
 		*(.rodata) *(.rodata.*) *(.data.rel.ro*)		\
 		SCHED_DATA						\
 		RO_AFTER_INIT_DATA	/* Read only after init */	\
-		. = ALIGN(8);						\
 		BOUNDED_SECTION_BY(__tracepoints_ptrs, ___tracepoints_ptrs) \
 		*(__tracepoints_strings)/* Tracepoints: strings */	\
 	}								\
@@ -947,12 +936,10 @@
 
 /* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */
 #define KUNIT_TABLE()							\
-		. = ALIGN(8);						\
 		BOUNDED_SECTION_POST_LABEL(.kunit_test_suites, __kunit_suites, _start, _end)
 
 /* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */
 #define KUNIT_INIT_TABLE()						\
-		. = ALIGN(8);						\
 		BOUNDED_SECTION_POST_LABEL(.kunit_init_test_suites, \
 				__kunit_init_suites, _start, _end)
 

-- 
2.55.0

[PATCH v6 05/24] dyndbg.lds.S: fix lost dyndbg sections in modules

[Jim Cromie]

With CONFIG_DRM_USE_DYNAMIC_DEBUG=y, several build configs had
problems with __dyndbg* sections getting lost in drm drivers.  Fix
this by following the model demonstrated in codetag.lds.h.

Introduce include/asm-generic/dyndbg.lds.h, to bundle dynamic-debug's
multiple sections together, into 2 macros:

vmlinux.lds.h DATA_DATA: move the 2 BOUNDED_SECTION_BY(__dyndbg*)
calls into dyndbg.lds.h DYNDBG_SECTIONS(). vmlinux.lds.h now includes
the new file and calls the new macro.

MOD_DYNDBG_SECTIONS keeps the 2 sections by name, aligns them and sets
the output address to 0 when the sections are empty.

dyndbg.lds.h includes (reuses) bounded-section.lds.h

scripts/module.lds.S: now calls MOD_DYNDBG_SECTIONS right before the
CODETAG macro (consistent with their placements in vmlinux.lds.h), and
also includes dyndbg.lds.h

This isolates vmlinux.lds.h from further __dyndbg section additions.

CC: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
---
v3: move #includes to top, drop extra ALIGN(8) in DYNDBG_SECTIONS, add RvBy

v2: Address linker script review feedback for relocatable modules.

MOD_DYNDBG_SECTIONS() used the BOUNDED_SECTION_BY() macro, which
proved problematic for kernel modules for two reasons:

1. Unwanted Empty Sections:
   BOUNDED_SECTION_BY() automatically generates `__start` and `__stop`
   symbols. When applied to `MOD_DYNDBG_SECTIONS()`, the linker assumes
   the sections are populated due to the symbol definitions, forcing an
   empty `__dyndbg` and `__dyndbg_classes` output section in every
   compiled module, even those without dynamic debug configuration.
   Since the module loader uses `section_objs()` to locate data via
   ELF headers instead of relying on `__start`/`__stop` symbols, these
   assignments are completely unnecessary.

2. Non-zero Output Addresses:
   During relocatable linking (e.g., `ld.bfd -r`), omitting an explicit
   base address causes the section to inherit the current location
   counter. This results in non-zero sh_addr values in `.ko` files,
   which is confusing, degrades compressibility, and can cause issues
   with external tools parsing the ELF.

Fix both issues by dropping `BOUNDED_SECTION_BY()` in favor of a simple
`KEEP(*(...))` constraint and explicitly defining the sections with a `0`
base address: `__dyndbg 0 : ALIGN(8) { ... }`.

fixup-inc-vml
---
 MAINTAINERS                       |  1 +
 include/asm-generic/dyndbg.lds.h  | 18 ++++++++++++++++++
 include/asm-generic/vmlinux.lds.h |  6 ++----
 scripts/module.lds.S              |  2 ++
 4 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index 4a8b0fd665ce..25400fee9f32 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9178,6 +9178,7 @@ DYNAMIC DEBUG
 M:	Jason Baron <jbaron@akamai.com>
 M:	Jim Cromie <jim.cromie@gmail.com>
 S:	Maintained
+F:	include/asm-generic/dyndbg.lds.h
 F:	include/linux/dynamic_debug.h
 F:	lib/dynamic_debug.c
 F:	lib/test_dynamic_debug.c
diff --git a/include/asm-generic/dyndbg.lds.h b/include/asm-generic/dyndbg.lds.h
new file mode 100644
index 000000000000..9d8951bef688
--- /dev/null
+++ b/include/asm-generic/dyndbg.lds.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ASM_GENERIC_DYNDBG_LDS_H
+#define __ASM_GENERIC_DYNDBG_LDS_H
+
+#include <asm-generic/bounded_sections.lds.h>
+#define DYNDBG_SECTIONS()					\
+	BOUNDED_SECTION_BY(__dyndbg, ___dyndbg)			\
+	BOUNDED_SECTION_BY(__dyndbg_classes, ___dyndbg_classes)
+
+#define MOD_DYNDBG_SECTIONS()						\
+	__dyndbg 0 : ALIGN(8) {						\
+		KEEP(*(__dyndbg))					\
+	}								\
+	__dyndbg_classes 0 : ALIGN(8) {					\
+		KEEP(*(__dyndbg_classes))				\
+	}
+
+#endif /* __ASM_GENERIC_DYNDBG_LDS_H */
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 3758a79d0430..bd60f278f762 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -52,6 +52,7 @@
 
 #include <asm-generic/bounded_sections.lds.h>
 #include <asm-generic/codetag.lds.h>
+#include <asm-generic/dyndbg.lds.h>
 
 #ifndef LOAD_OFFSET
 #define LOAD_OFFSET 0
@@ -344,10 +345,7 @@
 	*(.data..do_once)						\
 	STRUCT_ALIGN();							\
 	*(__tracepoints)						\
-	/* implement dynamic printk debug */				\
-	. = ALIGN(8);							\
-	BOUNDED_SECTION_BY(__dyndbg_classes, ___dyndbg_classes)		\
-	BOUNDED_SECTION_BY(__dyndbg, ___dyndbg)				\
+	DYNDBG_SECTIONS()						\
 	CODETAG_SECTIONS()						\
 	LIKELY_PROFILE()		       				\
 	BRANCH_PROFILE()						\
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index b62683061d79..2e62dc5bd5d4 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -10,6 +10,7 @@
 #endif
 
 #include <asm-generic/codetag.lds.h>
+#include <asm-generic/dyndbg.lds.h>
 
 SECTIONS {
 	/DISCARD/ : {
@@ -61,6 +62,7 @@ SECTIONS {
 		*(.rodata..L*)
 	}
 
+	MOD_DYNDBG_SECTIONS()
 	MOD_SEPARATE_CODETAG_SECTIONS()
 }
 

-- 
2.55.0

[PATCH v6 06/24] dyndbg: factor ddebug_match_desc out from ddebug_change

[Jim Cromie]

ddebug_change() is a big (~100 lines) function with a nested for loop.

The outer loop walks the per-module ddebug_tables list, and does
module stuff: it filters on a query's "module FOO*" and "class BAR",
failures here skip the entire inner loop.

The inner loop (60 lines) scans a module's descriptors.  It starts
with a long block of filters on function, line, format, and the
validated "BAR" class (or the legacy/_DPRINTK_CLASS_DFLT).

These filters "continue" past pr_debugs that don't match the query
criteria, before it falls through the code below that counts matches,
then adjusts the flags and static-keys.  This is unnecessarily hard to
think about.

So move the per-descriptor filter-block into a boolean function:
ddebug_match_desc(desc), and change each "continue" to "return false".
This puts a clear interface in place, so any future changes are either
inside, outside, or across this interface.

also fix checkpatch complaints about spaces and braces.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
v5: check for null format in callsite. shouldnt happen, but pr_debug() isnt illegal
---
 lib/dynamic_debug.c | 87 +++++++++++++++++++++++++++++++----------------------
 1 file changed, 51 insertions(+), 36 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 18a71a9108d3..577a07916072 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -172,6 +172,56 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons
  * callsites, normally the same as number of changes.  If verbose,
  * logs the changes.  Takes ddebug_lock.
  */
+static bool ddebug_match_desc(const struct ddebug_query *query,
+			      struct _ddebug *dp,
+			      int valid_class)
+{
+	/* match site against query-class */
+	if (dp->class_id != valid_class)
+		return false;
+
+	/* match against the source filename */
+	if (query->filename &&
+	    !match_wildcard(query->filename, dp->filename) &&
+	    !match_wildcard(query->filename,
+			    kbasename(dp->filename)) &&
+	    !match_wildcard(query->filename,
+			    trim_prefix(dp->filename)))
+		return false;
+
+	/* match against the function */
+	if (query->function &&
+	    !match_wildcard(query->function, dp->function))
+		return false;
+
+	/* match against the format */
+	if (query->format) {
+		if (!dp->format) {
+			pr_info("encountered a NULL format\n");
+			return false;
+		}
+		if (*query->format == '^') {
+			char *p;
+			/* anchored search. match must be at beginning */
+			p = strstr(dp->format, query->format + 1);
+			if (p != dp->format)
+				return false;
+		} else if (!strstr(dp->format, query->format)) {
+			return false;
+		}
+	}
+
+	/* match against the line number range */
+	if (query->first_lineno &&
+	    dp->lineno < query->first_lineno)
+		return false;
+	if (query->last_lineno &&
+	    dp->lineno > query->last_lineno)
+		return false;
+
+	return true;
+}
+
 static int ddebug_change(const struct ddebug_query *query,
 			 struct flag_settings *modifiers)
 {
@@ -204,42 +254,7 @@ static int ddebug_change(const struct ddebug_query *query,
 		for (i = 0; i < dt->num_ddebugs; i++) {
 			struct _ddebug *dp = &dt->ddebugs[i];
 
-			/* match site against query-class */
-			if (dp->class_id != valid_class)
-				continue;
-
-			/* match against the source filename */
-			if (query->filename &&
-			    !match_wildcard(query->filename, dp->filename) &&
-			    !match_wildcard(query->filename,
-					   kbasename(dp->filename)) &&
-			    !match_wildcard(query->filename,
-					   trim_prefix(dp->filename)))
-				continue;
-
-			/* match against the function */
-			if (query->function &&
-			    !match_wildcard(query->function, dp->function))
-				continue;
-
-			/* match against the format */
-			if (query->format) {
-				if (*query->format == '^') {
-					char *p;
-					/* anchored search. match must be at beginning */
-					p = strstr(dp->format, query->format+1);
-					if (p != dp->format)
-						continue;
-				} else if (!strstr(dp->format, query->format))
-					continue;
-			}
-
-			/* match against the line number range */
-			if (query->first_lineno &&
-			    dp->lineno < query->first_lineno)
-				continue;
-			if (query->last_lineno &&
-			    dp->lineno > query->last_lineno)
+			if (!ddebug_match_desc(query, dp, valid_class))
 				continue;
 
 			nfound++;

-- 
2.55.0

[PATCH v6 07/24] dyndbg: add stub macro for DECLARE_DYNDBG_CLASSMAP

[Jim Cromie]

Add the stub macro for !DYNAMIC_DEBUG builds, after moving the
original macro-defn down under the big ifdef.  Do it now so future
changes have a cleaner starting point.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 include/linux/dynamic_debug.h | 43 ++++++++++++++++++++++---------------------
 1 file changed, 22 insertions(+), 21 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 05743900a116..a10adac8e8f0 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -93,27 +93,6 @@ struct ddebug_class_map {
 	enum class_map_type map_type;
 };
 
-/**
- * DECLARE_DYNDBG_CLASSMAP - declare classnames known by a module
- * @_var:   a struct ddebug_class_map, passed to module_param_cb
- * @_type:  enum class_map_type, chooses bits/verbose, numeric/symbolic
- * @_base:  offset of 1st class-name. splits .class_id space
- * @classes: class-names used to control class'd prdbgs
- */
-#define DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, ...)		\
-	static const char *_var##_classnames[] = { __VA_ARGS__ };	\
-	static struct ddebug_class_map __aligned(8) __used		\
-		__section("__dyndbg_classes") _var = {			\
-		.mod = THIS_MODULE,					\
-		.mod_name = KBUILD_MODNAME,				\
-		.base = _base,						\
-		.map_type = _maptype,					\
-		.length = NUM_TYPE_ARGS(char*, __VA_ARGS__),		\
-		.class_names = _var##_classnames,			\
-	}
-#define NUM_TYPE_ARGS(eltype, ...)				\
-        (sizeof((eltype[]){__VA_ARGS__}) / sizeof(eltype))
-
 /* encapsulate linker provided built-in (or module) dyndbg data */
 struct _ddebug_info {
 	struct _ddebug *descs;
@@ -138,6 +117,27 @@ struct ddebug_class_param {
 #if defined(CONFIG_DYNAMIC_DEBUG) || \
 	(defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
 
+/**
+ * DECLARE_DYNDBG_CLASSMAP - declare classnames known by a module
+ * @_var:   a struct ddebug_class_map, passed to module_param_cb
+ * @_type:  enum class_map_type, chooses bits/verbose, numeric/symbolic
+ * @_base:  offset of 1st class-name. splits .class_id space
+ * @classes: class-names used to control class'd prdbgs
+ */
+#define DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, ...)		\
+	static const char *_var##_classnames[] = { __VA_ARGS__ };	\
+	static struct ddebug_class_map __aligned(8) __used		\
+		__section("__dyndbg_classes") _var = {			\
+		.mod = THIS_MODULE,					\
+		.mod_name = KBUILD_MODNAME,				\
+		.base = _base,						\
+		.map_type = _maptype,					\
+		.length = NUM_TYPE_ARGS(char*, __VA_ARGS__),		\
+		.class_names = _var##_classnames,			\
+	}
+#define NUM_TYPE_ARGS(eltype, ...)				\
+	(sizeof((eltype[]) {__VA_ARGS__}) / sizeof(eltype))
+
 extern __printf(2, 3)
 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
 
@@ -314,6 +314,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 
 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)
 #define DYNAMIC_DEBUG_BRANCH(descriptor) false
+#define DECLARE_DYNDBG_CLASSMAP(...)
 
 #define dynamic_pr_debug(fmt, ...)					\
 	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)

-- 
2.55.0

[PATCH v6 08/24] dyndbg: reword "class unknown," to "class:_UNKNOWN_"

[Jim Cromie]

When a dyndbg classname is unknown to a kernel module, the callsite is
un-addressable via >control queries, and therefore uncontrollable.

The control-file displays this condition as "class unknown, _id:N"
currently.  That spelling is sub-optimal/too-generic, so change it to
"class:_UNKNOWN_ _id:N" to loudly announce the erroneous situation,
and to make it uniquely greppable.

NB: while this might be seen as a user-visible change, this shouldn't
disqualify the change:

a- it reports a classmap coding error condition, which should be
   detected in (or before) review.
b- SHOUTING the error makes it more visible, uniquely greppable.
c- the classmap feature is marked BROKEN for its only current user.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 lib/dynamic_debug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 577a07916072..a86e1d5845e6 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1170,7 +1170,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 		if (class)
 			seq_printf(m, " class:%s", class);
 		else
-			seq_printf(m, " class unknown, _id:%d", dp->class_id);
+			seq_printf(m, " class:_UNKNOWN_ _id:%d", dp->class_id);
 	}
 	seq_putc(m, '\n');
 

-- 
2.55.0

[PATCH v6 09/24] dyndbg-API: remove DD_CLASS_TYPE_(DISJOINT|LEVEL)_NAMES and code

[Jim Cromie]

Remove the DD_CLASS_TYPE_*_NAMES classmap types and code.

These 2 classmap types accept class names at the PARAM interface, for
example:

  echo +DRM_UT_CORE,-DRM_UT_KMS > /sys/module/drm/parameters/debug_names

The code works, but its only used by test-dynamic-debug, and wasn't
asked for by anyone else, so reduce LOC & test-surface; simplify things.

Also rename enum class_map_type to enum ddebug_class_map_type.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
v3:

fix name of enum in kdoc
also change name of struct (to future name)

v2:

move RvB after SoB

respect const instr in param_set_dyndbg_module_classes, return -EINVAL on classtype err.
---
 include/linux/dynamic_debug.h | 28 ++++--------
 lib/dynamic_debug.c           | 99 +++----------------------------------------
 lib/test_dynamic_debug.c      | 26 ------------
 3 files changed, 15 insertions(+), 138 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index a10adac8e8f0..9607121c3072 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -59,27 +59,17 @@ struct _ddebug {
 #endif
 } __attribute__((aligned(8)));
 
-enum class_map_type {
+enum ddebug_class_map_type {
 	DD_CLASS_TYPE_DISJOINT_BITS,
 	/**
-	 * DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, one per bit.
-	 * expecting hex input. Built for drm.debug, basis for other types.
+	 * DD_CLASS_TYPE_DISJOINT_BITS: classes are independent,
+	 * mapped to bits[0..N].  Expects hex input. Built for
+	 * drm.debug, basis for other types.
 	 */
 	DD_CLASS_TYPE_LEVEL_NUM,
 	/**
-	 * DD_CLASS_TYPE_LEVEL_NUM: input is numeric level, 0-N.
-	 * N turns on just bits N-1 .. 0, so N=0 turns all bits off.
-	 */
-	DD_CLASS_TYPE_DISJOINT_NAMES,
-	/**
-	 * DD_CLASS_TYPE_DISJOINT_NAMES: input is a CSV of [+-]CLASS_NAMES,
-	 * classes are independent, like _DISJOINT_BITS.
-	 */
-	DD_CLASS_TYPE_LEVEL_NAMES,
-	/**
-	 * DD_CLASS_TYPE_LEVEL_NAMES: input is a CSV of [+-]CLASS_NAMES,
-	 * intended for names like: INFO,DEBUG,TRACE, with a module prefix
-	 * avoid EMERG,ALERT,CRIT,ERR,WARNING: they're not debug
+	 * DD_CLASS_TYPE_LEVEL_NUM: input is numeric level, 0..N.
+	 * Input N turns on bits 0..N-1
 	 */
 };
 
@@ -90,7 +80,7 @@ struct ddebug_class_map {
 	const char **class_names;
 	const int length;
 	const int base;		/* index of 1st .class_id, allows split/shared space */
-	enum class_map_type map_type;
+	enum ddebug_class_map_type map_type;
 };
 
 /* encapsulate linker provided built-in (or module) dyndbg data */
@@ -119,8 +109,8 @@ struct ddebug_class_param {
 
 /**
  * DECLARE_DYNDBG_CLASSMAP - declare classnames known by a module
- * @_var:   a struct ddebug_class_map, passed to module_param_cb
- * @_type:  enum class_map_type, chooses bits/verbose, numeric/symbolic
+ * @_var:   a struct _ddebug_class_map, passed to module_param_cb
+ * @_maptype: enum ddebug_class_map_type, chooses bits/verbose
  * @_base:  offset of 1st class-name. splits .class_id space
  * @classes: class-names used to control class'd prdbgs
  */
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index a86e1d5845e6..cd6b6c710ee2 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -650,76 +650,6 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 
 #define CLASSMAP_BITMASK(width) ((1UL << (width)) - 1)
 
-/* accept comma-separated-list of [+-] classnames */
-static int param_set_dyndbg_classnames(const char *instr, const struct kernel_param *kp)
-{
-	const struct ddebug_class_param *dcp = kp->arg;
-	const struct ddebug_class_map *map = dcp->map;
-	unsigned long curr_bits, old_bits;
-	char *cl_str, *p, *tmp;
-	int cls_id, totct = 0;
-	bool wanted;
-
-	cl_str = tmp = kstrdup_and_replace(instr, '\n', '\0', GFP_KERNEL);
-	if (!tmp)
-		return -ENOMEM;
-
-	/* start with previously set state-bits, then modify */
-	curr_bits = old_bits = *dcp->bits;
-	vpr_info("\"%s\" > %s:0x%lx\n", cl_str, KP_NAME(kp), curr_bits);
-
-	for (; cl_str; cl_str = p) {
-		p = strchr(cl_str, ',');
-		if (p)
-			*p++ = '\0';
-
-		if (*cl_str == '-') {
-			wanted = false;
-			cl_str++;
-		} else {
-			wanted = true;
-			if (*cl_str == '+')
-				cl_str++;
-		}
-		cls_id = match_string(map->class_names, map->length, cl_str);
-		if (cls_id < 0) {
-			pr_err("%s unknown to %s\n", cl_str, KP_NAME(kp));
-			continue;
-		}
-
-		/* have one or more valid class_ids of one *_NAMES type */
-		switch (map->map_type) {
-		case DD_CLASS_TYPE_DISJOINT_NAMES:
-			/* the +/- pertains to a single bit */
-			if (test_bit(cls_id, &curr_bits) == wanted) {
-				v3pr_info("no change on %s\n", cl_str);
-				continue;
-			}
-			curr_bits ^= BIT(cls_id);
-			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, dcp->bits);
-			*dcp->bits = curr_bits;
-			v2pr_info("%s: changed bit %d:%s\n", KP_NAME(kp), cls_id,
-				  map->class_names[cls_id]);
-			break;
-		case DD_CLASS_TYPE_LEVEL_NAMES:
-			/* cls_id = N in 0..max. wanted +/- determines N or N-1 */
-			old_bits = CLASSMAP_BITMASK(*dcp->lvl);
-			curr_bits = CLASSMAP_BITMASK(cls_id + (wanted ? 1 : 0 ));
-
-			totct += ddebug_apply_class_bitmap(dcp, &curr_bits, &old_bits);
-			*dcp->lvl = (cls_id + (wanted ? 1 : 0));
-			v2pr_info("%s: changed bit-%d: \"%s\" %lx->%lx\n", KP_NAME(kp), cls_id,
-				  map->class_names[cls_id], old_bits, curr_bits);
-			break;
-		default:
-			pr_err("illegal map-type value %d\n", map->map_type);
-		}
-	}
-	kfree(tmp);
-	vpr_info("total matches: %d\n", totct);
-	return 0;
-}
-
 /**
  * param_set_dyndbg_classes - class FOO >control
  * @instr: string echo>d to sysfs, input depends on map_type
@@ -738,28 +668,14 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 	unsigned long inrep, new_bits, old_bits;
 	int rc, totct = 0;
 
-	switch (map->map_type) {
-
-	case DD_CLASS_TYPE_DISJOINT_NAMES:
-	case DD_CLASS_TYPE_LEVEL_NAMES:
-		/* handle [+-]classnames list separately, we are done here */
-		return param_set_dyndbg_classnames(instr, kp);
-
-	case DD_CLASS_TYPE_DISJOINT_BITS:
-	case DD_CLASS_TYPE_LEVEL_NUM:
-		/* numeric input, accept and fall-thru */
-		rc = kstrtoul(instr, 0, &inrep);
-		if (rc) {
-			pr_err("expecting numeric input: %s > %s\n", instr, KP_NAME(kp));
-			return -EINVAL;
-		}
-		break;
-	default:
-		pr_err("%s: bad map type: %d\n", KP_NAME(kp), map->map_type);
+	rc = kstrtoul(instr, 0, &inrep);
+	if (rc) {
+		int len = strcspn(instr, "\n");
+		pr_err("expecting numeric input, not: %.*s > %s\n",
+		       len, instr, KP_NAME(kp));
 		return -EINVAL;
 	}
 
-	/* only _BITS,_NUM (numeric) map-types get here */
 	switch (map->map_type) {
 	case DD_CLASS_TYPE_DISJOINT_BITS:
 		/* expect bits. mask and warn if too many */
@@ -787,6 +703,7 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 		break;
 	default:
 		pr_warn("%s: bad map type: %d\n", KP_NAME(kp), map->map_type);
+		return -EINVAL;
 	}
 	vpr_info("%s: total matches: %d\n", KP_NAME(kp), totct);
 	return 0;
@@ -808,12 +725,8 @@ int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
 	const struct ddebug_class_map *map = dcp->map;
 
 	switch (map->map_type) {
-
-	case DD_CLASS_TYPE_DISJOINT_NAMES:
 	case DD_CLASS_TYPE_DISJOINT_BITS:
 		return scnprintf(buffer, PAGE_SIZE, "0x%lx\n", *dcp->bits);
-
-	case DD_CLASS_TYPE_LEVEL_NAMES:
 	case DD_CLASS_TYPE_LEVEL_NUM:
 		return scnprintf(buffer, PAGE_SIZE, "%d\n", *dcp->lvl);
 	default:
diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index 77c2a669b6af..74d183ebf3e0 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -74,13 +74,6 @@ DECLARE_DYNDBG_CLASSMAP(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS, 0,
 DD_SYS_WRAP(disjoint_bits, p);
 DD_SYS_WRAP(disjoint_bits, T);
 
-/* symbolic input, independent bits */
-enum cat_disjoint_names { LOW = 11, MID, HI };
-DECLARE_DYNDBG_CLASSMAP(map_disjoint_names, DD_CLASS_TYPE_DISJOINT_NAMES, 10,
-			"LOW", "MID", "HI");
-DD_SYS_WRAP(disjoint_names, p);
-DD_SYS_WRAP(disjoint_names, T);
-
 /* numeric verbosity, V2 > V1 related */
 enum cat_level_num { V0 = 14, V1, V2, V3, V4, V5, V6, V7 };
 DECLARE_DYNDBG_CLASSMAP(map_level_num, DD_CLASS_TYPE_LEVEL_NUM, 14,
@@ -88,13 +81,6 @@ DECLARE_DYNDBG_CLASSMAP(map_level_num, DD_CLASS_TYPE_LEVEL_NUM, 14,
 DD_SYS_WRAP(level_num, p);
 DD_SYS_WRAP(level_num, T);
 
-/* symbolic verbosity */
-enum cat_level_names { L0 = 22, L1, L2, L3, L4, L5, L6, L7 };
-DECLARE_DYNDBG_CLASSMAP(map_level_names, DD_CLASS_TYPE_LEVEL_NAMES, 22,
-			"L0", "L1", "L2", "L3", "L4", "L5", "L6", "L7");
-DD_SYS_WRAP(level_names, p);
-DD_SYS_WRAP(level_names, T);
-
 /* stand-in for all pr_debug etc */
 #define prdbg(SYM) __pr_debug_cls(SYM, #SYM " msg\n")
 
@@ -102,10 +88,6 @@ static void do_cats(void)
 {
 	pr_debug("doing categories\n");
 
-	prdbg(LOW);
-	prdbg(MID);
-	prdbg(HI);
-
 	prdbg(D2_CORE);
 	prdbg(D2_DRIVER);
 	prdbg(D2_KMS);
@@ -129,14 +111,6 @@ static void do_levels(void)
 	prdbg(V5);
 	prdbg(V6);
 	prdbg(V7);
-
-	prdbg(L1);
-	prdbg(L2);
-	prdbg(L3);
-	prdbg(L4);
-	prdbg(L5);
-	prdbg(L6);
-	prdbg(L7);
 }
 
 static void do_prints(void)

-- 
2.55.0

[PATCH v6 10/24] dyndbg: drop NUM_TYPE_ARGS

[Jim Cromie]

ARRAY_SIZE almost works here, since array decl is complete.
But define it locally, named __DDEBUG_ARRAY_SIZE, to avoid
include conflicts with  boot/<something> on some arch.

no functional change

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
v5: drop include, it causes redefined probs in /boot/* for some arch.
v2: include linux/array_size.h, correct commit subject, review after sob
---
 include/linux/dynamic_debug.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 9607121c3072..9ae1accb9bf6 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -8,6 +8,8 @@
 
 #include <linux/build_bug.h>
 
+#define __DDEBUG_ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+
 /*
  * An instance of this structure is created in a special
  * ELF section at every dynamic debug callsite.  At runtime,
@@ -122,11 +124,9 @@ struct ddebug_class_param {
 		.mod_name = KBUILD_MODNAME,				\
 		.base = _base,						\
 		.map_type = _maptype,					\
-		.length = NUM_TYPE_ARGS(char*, __VA_ARGS__),		\
+		.length = (sizeof(_var##_classnames) / sizeof(_var##_classnames[0])), \
 		.class_names = _var##_classnames,			\
 	}
-#define NUM_TYPE_ARGS(eltype, ...)				\
-	(sizeof((eltype[]) {__VA_ARGS__}) / sizeof(eltype))
 
 extern __printf(2, 3)
 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);

-- 
2.55.0

[PATCH v6 11/24] dyndbg: bump num-tokens in a query-cmd from 9 to 15

[Jim Cromie]

Current MAXWORDS in ddebug_exec_query() is too small to accept a legal
query-command using all 6 keywords.  We *need* 13, but this adds a few
extra to allow certain errors to fail on subsequent, more meaningful
grammar checks.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
 lib/dynamic_debug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index cd6b6c710ee2..efe12fac6363 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -554,7 +554,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
 {
 	struct flag_settings modifiers = {};
 	struct ddebug_query query = {};
-#define MAXWORDS 9
+#define MAXWORDS 15
 	int nwords, nfound;
 	char *words[MAXWORDS];
 

-- 
2.55.0

[PATCH v6 12/24] dyndbg: reduce verbose/debug clutter

[Jim Cromie]

currently, for verbose=3, these are logged (blank lines for clarity):

 dyndbg: query 0: "class DRM_UT_CORE +p" mod:*
 dyndbg: split into words: "class" "DRM_UT_CORE" "+p"

 dyndbg: op='+'
 dyndbg: flags=0x1
 dyndbg: *flagsp=0x1 *maskp=0xffffffff

 dyndbg: parsed: func="" file="" module="" format="" lineno=0-0 class=...
 dyndbg: no matches for query
 dyndbg: no-match: func="" file="" module="" format="" lineno=0-0 class=...
 dyndbg: processed 1 queries, with 0 matches, 0 errs

That is excessive, so this patch:
 - shrinks 3 lines of 2nd stanza to single line
 - drops 1st 2 lines of 3rd stanza
   3rd line is like 1st, with result, not procedure.
   2nd line is just status, retold in 4th, with more info.

New output:

 dyndbg: query 0: "class DRM_UT_CORE +p"
 dyndbg: split into words: "class" "DRM_UT_CORE" "+p"
 dyndbg: op='+' flags=0x1 maskp=0xffffffff
 dyndbg: processed 1 queries, with 0 matches, 0 errs

Also drop several verbose=3 messages in ddebug_add_module.  When
modprobing a module, dyndbg currently logs/says "add-module", and then
"skipping" if the module has no prdbgs.  Instead just check 1st and
return quietly.

Unmatched query diagnostics are intentionally restricted to verbose
level 3 (v3pr_info_dq) to reduce dmesg output clutter on standard
verbose levels (verbose=1 and verbose=2), aligning with the overall
de-cluttering of dynamic debug logging.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
v4: rename vpr_dq_info to v3pr_dq_info to tell its active logging level
    adjust some vX levels per doc'd intentions
v2: RvB after SoB

trivial change to verbose-debug output line to output the actual
"module" keyword rather than "mod:", and do so only when the module is
constrained by the callchain (ie as part of a modprobe).

 was:   query X: "(keyword value)* [+-=]flags" mod:*
 now:   query X: "(keyword value)* [+-=]flags"
   or   query X: module FOO "keyword value)* [+-=]flags"

IOW, adjust output to reflect the input grammar more closely.

drop-info-parsed

vinfo-applied-nomatch

dyndbg: tweak verbose-levels per doc
---
 lib/dynamic_debug.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index efe12fac6363..2e321b7eb957 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -128,7 +128,7 @@ do {								\
 #define v3pr_info(fmt, ...)	vnpr_info(3, fmt, ##__VA_ARGS__)
 #define v4pr_info(fmt, ...)	vnpr_info(4, fmt, ##__VA_ARGS__)
 
-static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
+static void v3pr_info_dq(const struct ddebug_query *query, const char *msg)
 {
 	/* trim any trailing newlines */
 	int fmtlen = 0;
@@ -280,9 +280,6 @@ static int ddebug_change(const struct ddebug_query *query,
 	}
 	mutex_unlock(&ddebug_lock);
 
-	if (!nfound && verbose)
-		pr_info("no matches for query\n");
-
 	return nfound;
 }
 
@@ -491,7 +488,6 @@ static int ddebug_parse_query(char *words[], int nwords,
 		 */
 		query->module = modname;
 
-	vpr_info_dq(query, "parsed");
 	return 0;
 }
 
@@ -515,7 +511,6 @@ static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
 		pr_err("bad flag-op %c, at start of %s\n", *str, str);
 		return -EINVAL;
 	}
-	v3pr_info("op='%c'\n", op);
 
 	for (; *str ; ++str) {
 		for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
@@ -529,7 +524,6 @@ static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
 			return -EINVAL;
 		}
 	}
-	v3pr_info("flags=0x%x\n", modifiers->flags);
 
 	/* calculate final flags, mask based upon op */
 	switch (op) {
@@ -545,7 +539,7 @@ static int ddebug_parse_flags(const char *str, struct flag_settings *modifiers)
 		modifiers->flags = 0;
 		break;
 	}
-	v3pr_info("*flagsp=0x%x *maskp=0x%x\n", modifiers->flags, modifiers->mask);
+	v3pr_info("op='%c' flags=0x%x maskp=0x%x\n", op, modifiers->flags, modifiers->mask);
 
 	return 0;
 }
@@ -574,7 +568,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
 	}
 	/* actually go and implement the change */
 	nfound = ddebug_change(&query, &modifiers);
-	vpr_info_dq(&query, nfound ? "applied" : "no-match");
+	v3pr_info_dq(&query, nfound ? "applied" : "no-match");
 
 	return nfound;
 }
@@ -597,7 +591,10 @@ static int ddebug_exec_queries(char *query, const char *modname)
 		if (!query || !*query || *query == '#')
 			continue;
 
-		vpr_info("query %d: \"%s\" mod:%s\n", i, query, modname ?: "*");
+		if (modname)
+			v2pr_info("query %d: module %s \"%s\"\n", i, modname, query);
+		else
+			v2pr_info("query %d: \"%s\"\n", i, query);
 
 		rc = ddebug_exec_query(query, modname);
 		if (rc < 0) {
@@ -1163,11 +1160,10 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 {
 	struct ddebug_table *dt;
 
-	v3pr_info("add-module: %s.%d sites\n", modname, di->num_descs);
-	if (!di->num_descs) {
-		v3pr_info(" skip %s\n", modname);
+	if (!di->num_descs)
 		return 0;
-	}
+
+	v3pr_info("add-module: %s %d sites\n", modname, di->num_descs);
 
 	dt = kzalloc_obj(*dt);
 	if (dt == NULL) {

-- 
2.55.0

[PATCH v6 13/24] lib/parser: add match_wildcard_hyphen() for agnostic matching

[Jim Cromie]

This commit introduces match_wildcard_hyphen() as a variant of the
existing match_wildcard() function. It treats hyphens and underscores
as identical characters during the matching process.

This is necessary for subsystems like dynamic_debug that need to match
module names provided by users (who often use underscores) against
names stored in the kernel (which may use hyphens, especially when
using KBUILD_MODFILE for built-ins).

To avoid code duplication, the core logic is refactored into a private
__match_wildcard() function marked as __always_inline. This allows the
compiler to generate optimized versions for both the strict and agnostic
callsites with zero runtime overhead.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v5: move ahead of array-slice patch to silence sashiko complaint about it
v4: initial version
---
 include/linux/parser.h |  1 +
 lib/parser.c           | 58 +++++++++++++++++++++++++++++++++++++-------------
 2 files changed, 44 insertions(+), 15 deletions(-)

diff --git a/include/linux/parser.h b/include/linux/parser.h
index dd79f45a37b8..a3cc7bc5fb93 100644
--- a/include/linux/parser.h
+++ b/include/linux/parser.h
@@ -34,6 +34,7 @@ int match_u64(substring_t *, u64 *result);
 int match_octal(substring_t *, int *result);
 int match_hex(substring_t *, int *result);
 bool match_wildcard(const char *pattern, const char *str);
+bool match_wildcard_hyphen(const char *pattern, const char *str);
 size_t match_strlcpy(char *, const substring_t *, size_t);
 char *match_strdup(const substring_t *);
 
diff --git a/lib/parser.c b/lib/parser.c
index 62da0ac0d438..d5be01fa9adf 100644
--- a/lib/parser.c
+++ b/lib/parser.c
@@ -268,20 +268,13 @@ int match_hex(substring_t *s, int *result)
 }
 EXPORT_SYMBOL(match_hex);
 
-/**
- * match_wildcard - parse if a string matches given wildcard pattern
- * @pattern: wildcard pattern
- * @str: the string to be parsed
- *
- * Description: Parse the string @str to check if matches wildcard
- * pattern @pattern. The pattern may contain two types of wildcards:
- *
- * * '*' - matches zero or more characters
- * * '?' - matches one character
- *
- * Return: If the @str matches the @pattern, return true, else return false.
- */
-bool match_wildcard(const char *pattern, const char *str)
+static inline char dash2underscore(char c)
+{
+	return (c == '-') ? '_' : c;
+}
+
+static __always_inline bool __match_wildcard(const char *pattern, const char *str,
+					     bool hyphen_agnostic)
 {
 	const char *s = str;
 	const char *p = pattern;
@@ -301,7 +294,9 @@ bool match_wildcard(const char *pattern, const char *str)
 			pattern = p;
 			break;
 		default:
-			if (*s == *p) {
+			if (hyphen_agnostic ?
+			    (dash2underscore(*s) == dash2underscore(*p)) :
+			    (*s == *p)) {
 				s++;
 				p++;
 			} else {
@@ -319,8 +314,41 @@ bool match_wildcard(const char *pattern, const char *str)
 		++p;
 	return !*p;
 }
+
+/**
+ * match_wildcard - parse if a string matches given wildcard pattern
+ * @pattern: wildcard pattern
+ * @str: the string to be parsed
+ *
+ * Description: Parse the string @str to check if matches wildcard
+ * pattern @pattern. The pattern may contain two types of wildcards:
+ *
+ * * '*' - matches zero or more characters
+ * * '?' - matches one character
+ *
+ * Return: If the @str matches the @pattern, return true, else return false.
+ */
+bool match_wildcard(const char *pattern, const char *str)
+{
+	return __match_wildcard(pattern, str, false);
+}
 EXPORT_SYMBOL(match_wildcard);
 
+/**
+ * match_wildcard_hyphen - parse if a string matches given wildcard pattern
+ * @pattern: wildcard pattern
+ * @str: the string to be parsed
+ *
+ * Description: Same as match_wildcard, but treats '-' and '_' as identical.
+ *
+ * Return: If the @str matches the @pattern, return true, else return false.
+ */
+bool match_wildcard_hyphen(const char *pattern, const char *str)
+{
+	return __match_wildcard(pattern, str, true);
+}
+EXPORT_SYMBOL(match_wildcard_hyphen);
+
 /**
  * match_strlcpy - Copy the characters from a substring_t to a sized buffer
  * @dest: where to copy to

-- 
2.55.0

[PATCH v6 14/24] dyndbg: use KBUILD_MODFILE for unique builtin module names

[Jim Cromie]

Historically dynamic-debug gets its module names from KBUILD_MODNAME.
This works well for loadable modules, as the module loader has always
required them to have unique names, but for builtins it is basically
kbasename(srcfile), which sadly gives us many modules named "main".

IOW, it makes this ambiguous:
  bash-5.3# echo module main +m > /proc/dynamic_debug/control

since it would affect all 4 independent modules named main:
  bash-5.3# ddgrep =m
  init/main.c:1265 [main]initcall_blacklist =m "blacklisting initcall %s\n"
  kernel/power/main.c:49 [main]pm_restore_gfp_mask =m "GFP mask restored\n"
  kernel/module/main.c:2862 [main]move_module =m "\t0x%lx 0x%.8lx %s\n"
  drivers/base/power/main.c:149 [main]device_pm_add =m "Adding info for %s:%s\n"

We can improve this by using KBUILD_MODFILE for dyndbg's modname in
builtins (which is unique), and KBUILD_MODNAME for loadables (which is
already required/guaranteed to be unique by module-loader):

The above control-file entries then become:
  init/main.c:1265 [init/main]initcall_blacklist ...
  kernel/power/main.c:49 [kernel/power/main]pm_restore_gfp_mask ...
  kernel/module/main.c:2862 [kernel/module/main]move_module ...
  drivers/base/power/main.c:149 [drivers/base/power/main]device_pm_add ...

While this is a user visible change; [params] becomes [kernel/params]
etc, it is not a behavior change; we now match the query-module
against the subsystem/module name or its kbasename (the
simple-modname), which as before, matches all 4 modules.

This allows queries to be specific when desired: "module init/main",
while preserving the existing meaning of "module main"

The deeper reason for this change is not obvious.  If any builtin
"main" module were to add a classmap, it would attach to all "main"
modules.  If 2 "main" modules defined separate classmaps, both modules
would inadvertently share both classmaps.  Since classmaps map
classnames to 0..62, and independently defined classmaps are most
likely to start at 0 (unless author is planning to share the 0..62
range with other classmaps), we have a setup for later reserved range
conflicts.  Having unique names prevents future conflicts.

This solution isn't perfect:
1. it changes displayed [params] to [kernel/params] etc
2. its mostly redundant with "filename */main.*"
3. Ideally, queries like "module power", "module module", "module
   base/power" might be better but would break old queries.

Adding classmaps to the builtins named "[main]" is unlikely, so this
change isn't absolutely necessary, but it seemed proper to at least
address the latent problem.

Adjust Documentation with "simple modname" and "subsystem modname".

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v5: move ahead of array-slice patch to silence sashiko complaint about it
v4: call match_wildcard_hyphen() to allow dash vs underscore modname equivalence
v3: use KBUILD_MODFILE to give unique modnames for builtins
---
 Documentation/admin-guide/dynamic-debug-howto.rst | 42 +++++++++++++----------
 include/linux/dynamic_debug.h                     | 15 ++++++--
 lib/dynamic_debug.c                               |  3 +-
 3 files changed, 38 insertions(+), 22 deletions(-)

diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 9c2f096ed1d8..99bbae37d34e 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -38,12 +38,12 @@ You can view the currently configured behaviour in the *prdbg* catalog::
 
   :#> head -n7 /proc/dynamic_debug/control
   # filename:lineno [module]function flags format
-  init/main.c:1179 [main]initcall_blacklist =_ "blacklisting initcall %s\n"
-  init/main.c:1218 [main]initcall_blacklisted =_ "initcall %s blacklisted\n"
-  init/main.c:1424 [main]run_init_process =_ "  with arguments:\n"
-  init/main.c:1426 [main]run_init_process =_ "    %s\n"
-  init/main.c:1427 [main]run_init_process =_ "  with environment:\n"
-  init/main.c:1429 [main]run_init_process =_ "    %s\n"
+  init/main.c:1179 [init/main]initcall_blacklist =_ "blacklisting initcall %s\n"
+  init/main.c:1218 [init/main]initcall_blacklisted =_ "initcall %s blacklisted\n"
+  init/main.c:1424 [init/main]run_init_process =_ "  with arguments:\n"
+  init/main.c:1426 [init/main]run_init_process =_ "    %s\n"
+  init/main.c:1427 [init/main]run_init_process =_ "  with environment:\n"
+  init/main.c:1429 [init/main]run_init_process =_ "    %s\n"
 
 The 3rd space-delimited column shows the current flags, preceded by
 a ``=`` for easy use with grep/cut. ``=p`` shows enabled callsites.
@@ -59,10 +59,10 @@ query/commands to the control file.  Example::
 
   :#> ddcmd '-p; module main func run* +p'
   :#> grep =p /proc/dynamic_debug/control
-  init/main.c:1424 [main]run_init_process =p "  with arguments:\n"
-  init/main.c:1426 [main]run_init_process =p "    %s\n"
-  init/main.c:1427 [main]run_init_process =p "  with environment:\n"
-  init/main.c:1429 [main]run_init_process =p "    %s\n"
+  init/main.c:1424 [init/main]run_init_process =p "  with arguments:\n"
+  init/main.c:1426 [init/main]run_init_process =p "    %s\n"
+  init/main.c:1427 [init/main]run_init_process =p "  with environment:\n"
+  init/main.c:1429 [init/main]run_init_process =p "    %s\n"
 
 Error messages go to console/syslog::
 
@@ -161,17 +161,21 @@ file
 	file kernel/freezer.c	# ie column 1 of control file
 	file drivers/usb/*	# all callsites under it
 	file inode.c:start_*	# parse :tail as a func (above)
-	file inode.c:1-100	# parse :tail as a line-range (above)
+	file inode.c:1-100	# parse :tail as a line-range (below)
 
 module
-    The given string is compared against the module name
-    of each callsite.  The module name is the string as
-    seen in ``lsmod``, i.e. without the directory or the ``.ko``
-    suffix and with ``-`` changed to ``_``.  Examples::
-
-	module sunrpc
-	module nfsd
-	module drm*	# both drm, drm_kms_helper
+    The query string is compared against the subsystem module name of
+    each callsite, as shown in the control file, or its simple name.
+    The simple module name is the string as seen in ``lsmod``,
+    i.e. without the directory or the ``.ko`` suffix and with ``-``
+    changed to ``_``.
+    Examples::
+
+        module nfsd        # simple modname (as from lsmod)
+	module init/main   # subsystem modname (as in control file)
+	module */main	   # any subsystem ending in main
+        module main	   # simple modname, selects same as above
+	module drm*	   # both drm, drm_kms_helper
 
 format
     The given string is searched for in the dynamic debug format
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 9ae1accb9bf6..da9e5c35bc43 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -10,6 +10,17 @@
 
 #define __DDEBUG_ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 
+/*
+ * Pick the best name for the module:
+ * KBUILD_MODFILE includes the path (e.g., drivers/usb/core/usbcore) for built-ins.
+ * Fall back to KBUILD_MODNAME for modules (loader requires unique names).
+ */
+#ifdef KBUILD_MODFILE
+# define DDEBUG_MODNAME KBUILD_MODFILE
+#else
+# define DDEBUG_MODNAME KBUILD_MODNAME
+#endif
+
 /*
  * An instance of this structure is created in a special
  * ELF section at every dynamic debug callsite.  At runtime,
@@ -121,7 +132,7 @@ struct ddebug_class_param {
 	static struct ddebug_class_map __aligned(8) __used		\
 		__section("__dyndbg_classes") _var = {			\
 		.mod = THIS_MODULE,					\
-		.mod_name = KBUILD_MODNAME,				\
+		.mod_name = DDEBUG_MODNAME,				\
 		.base = _base,						\
 		.map_type = _maptype,					\
 		.length = (sizeof(_var##_classnames) / sizeof(_var##_classnames[0])), \
@@ -160,7 +171,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 #define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt)	\
 	static struct _ddebug  __aligned(8)			\
 	__section("__dyndbg") name = {				\
-		.modname = KBUILD_MODNAME,			\
+		.modname = DDEBUG_MODNAME,			\
 		.function = __func__,				\
 		.filename = __FILE__,				\
 		.format = (fmt),				\
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 2e321b7eb957..ce42e03f1600 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -239,7 +239,8 @@ static int ddebug_change(const struct ddebug_query *query,
 
 		/* match against the module name */
 		if (query->module &&
-		    !match_wildcard(query->module, dt->mod_name))
+		    !match_wildcard_hyphen(query->module, dt->mod_name) &&
+		    !match_wildcard_hyphen(query->module, kbasename(dt->mod_name)))
 			continue;
 
 		if (query->class_string) {

-- 
2.55.0

[PATCH v6 15/24] dyndbg: refactor param_set_dyndbg_classes and below

[Jim Cromie]

Refactor the callchain below param_set_dyndbg_classes(1) to allow
mod-name specific settings.  Split (1) into upper/lower fns, adding
modname param to lower, and passing NULL in from upper.  Below that,
add the same param to ddebug_apply_class_bitmap(), and pass it thru to
_ddebug_queries(), replacing NULL with the param.

This allows the callchain to update the classmap in just one module,
vs just all as currently done.  While the sysfs param is unlikely to
ever update just one module, the callchain will be used for modprobe
handling, which should update only that just-probed module.

In ddebug_apply_class_bitmap(), also check for actual changes to the
bits before announcing them, to declutter logs.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
v2: move RvB after SoB
---
 lib/dynamic_debug.c | 51 +++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 39 insertions(+), 12 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index ce42e03f1600..0fc9cd14e2d2 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -615,9 +615,10 @@ static int ddebug_exec_queries(char *query, const char *modname)
 	return nfound;
 }
 
-/* apply a new bitmap to the sys-knob's current bit-state */
+/* apply a new class-param setting */
 static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
-				     unsigned long *new_bits, unsigned long *old_bits)
+				     unsigned long *new_bits, unsigned long *old_bits,
+				     const char *query_modname)
 {
 #define QUERY_SIZE 128
 	char query[QUERY_SIZE];
@@ -625,7 +626,9 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 	int matches = 0;
 	int bi, ct;
 
-	v2pr_info("apply: 0x%lx to: 0x%lx\n", *new_bits, *old_bits);
+	if (*new_bits != *old_bits)
+		v2pr_info("apply bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
+			  *old_bits, query_modname ?: "'*'");
 
 	for (bi = 0; bi < map->length; bi++) {
 		if (test_bit(bi, new_bits) == test_bit(bi, old_bits))
@@ -634,12 +637,16 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 		snprintf(query, QUERY_SIZE, "class %s %c%s", map->class_names[bi],
 			 test_bit(bi, new_bits) ? '+' : '-', dcp->flags);
 
-		ct = ddebug_exec_queries(query, NULL);
+		ct = ddebug_exec_queries(query, query_modname);
 		matches += ct;
 
 		v2pr_info("bit_%d: %d matches on class: %s -> 0x%lx\n", bi,
 			  ct, map->class_names[bi], *new_bits);
 	}
+	if (*new_bits != *old_bits)
+		v2pr_info("applied bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
+			  *old_bits, query_modname ?: "'*'");
+
 	return matches;
 }
 
@@ -652,6 +659,7 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
  * param_set_dyndbg_classes - class FOO >control
  * @instr: string echo>d to sysfs, input depends on map_type
  * @kp:    kp->arg has state: bits/lvl, map, map_type
+ * @mod_name: module name or null for all modules with the classes
  *
  * Enable/disable prdbgs by their class, as given in the arguments to
  * DECLARE_DYNDBG_CLASSMAP.  For LEVEL map-types, enforce relative
@@ -659,7 +667,9 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
  *
  * Returns: 0 or <0 if error.
  */
-int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
+static int param_set_dyndbg_module_classes(const char *instr,
+					   const struct kernel_param *kp,
+					   const char *mod_name)
 {
 	const struct ddebug_class_param *dcp = kp->arg;
 	const struct ddebug_class_map *map = dcp->map;
@@ -682,8 +692,8 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 				KP_NAME(kp), inrep, CLASSMAP_BITMASK(map->length));
 			inrep &= CLASSMAP_BITMASK(map->length);
 		}
-		v2pr_info("bits:%lx > %s\n", inrep, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits);
+		v2pr_info("bits:0x%lx > %s.%s\n", inrep, mod_name ?: "*", KP_NAME(kp));
+		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits, mod_name);
 		*dcp->bits = inrep;
 		break;
 	case DD_CLASS_TYPE_LEVEL_NUM:
@@ -696,7 +706,7 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 		old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 		new_bits = CLASSMAP_BITMASK(inrep);
 		v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits);
+		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits, mod_name);
 		*dcp->lvl = inrep;
 		break;
 	default:
@@ -706,16 +716,33 @@ int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
 	vpr_info("%s: total matches: %d\n", KP_NAME(kp), totct);
 	return 0;
 }
+
+/**
+ * param_set_dyndbg_classes - classmap kparam setter
+ * @instr: string echo>d to sysfs, input depends on map_type
+ * @kp:    kp->arg has state: bits/lvl, map, map_type
+ *
+ * enable/disable all class'd pr_debugs in the classmap. For LEVEL
+ * map-types, enforce * relative levels by bitpos.
+ *
+ * Returns: 0 or <0 if error.
+ */
+int param_set_dyndbg_classes(const char *instr, const struct kernel_param *kp)
+{
+	return param_set_dyndbg_module_classes(instr, kp, NULL);
+}
 EXPORT_SYMBOL(param_set_dyndbg_classes);
 
 /**
- * param_get_dyndbg_classes - classes reader
+ * param_get_dyndbg_classes - classmap kparam getter
  * @buffer: string description of controlled bits -> classes
  * @kp:     kp->arg has state: bits, map
  *
- * Reads last written state, underlying prdbg state may have been
- * altered by direct >control.  Displays 0x for DISJOINT, 0-N for
- * LEVEL Returns: #chars written or <0 on error
+ * Reads last written state, underlying pr_debug states may have been
+ * altered by direct >control.  Displays 0x for DISJOINT classmap
+ * types, 0-N for LEVEL types.
+ *
+ * Returns: ct of chars written or <0 on error
  */
 int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
 {

-- 
2.55.0

[PATCH v6 16/24] dyndbg: tighten fn-sig of ddebug_apply_class_bitmap

[Jim Cromie]

old_bits arg is currently a pointer to the input bits, but this could
allow inadvertent changes to the input by the fn.  Disallow this.
And constify new_bits while here.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
v2: move RvB after SoB
---
 lib/dynamic_debug.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 0fc9cd14e2d2..8c3b29904346 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -617,7 +617,8 @@ static int ddebug_exec_queries(char *query, const char *modname)
 
 /* apply a new class-param setting */
 static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
-				     unsigned long *new_bits, unsigned long *old_bits,
+				     const unsigned long *new_bits,
+				     const unsigned long old_bits,
 				     const char *query_modname)
 {
 #define QUERY_SIZE 128
@@ -626,12 +627,12 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 	int matches = 0;
 	int bi, ct;
 
-	if (*new_bits != *old_bits)
+	if (*new_bits != old_bits)
 		v2pr_info("apply bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
-			  *old_bits, query_modname ?: "'*'");
+			  old_bits, query_modname ?: "'*'");
 
 	for (bi = 0; bi < map->length; bi++) {
-		if (test_bit(bi, new_bits) == test_bit(bi, old_bits))
+		if (test_bit(bi, new_bits) == test_bit(bi, &old_bits))
 			continue;
 
 		snprintf(query, QUERY_SIZE, "class %s %c%s", map->class_names[bi],
@@ -643,9 +644,9 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 		v2pr_info("bit_%d: %d matches on class: %s -> 0x%lx\n", bi,
 			  ct, map->class_names[bi], *new_bits);
 	}
-	if (*new_bits != *old_bits)
+	if (*new_bits != old_bits)
 		v2pr_info("applied bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
-			  *old_bits, query_modname ?: "'*'");
+			  old_bits, query_modname ?: "'*'");
 
 	return matches;
 }
@@ -693,7 +694,7 @@ static int param_set_dyndbg_module_classes(const char *instr,
 			inrep &= CLASSMAP_BITMASK(map->length);
 		}
 		v2pr_info("bits:0x%lx > %s.%s\n", inrep, mod_name ?: "*", KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &inrep, dcp->bits, mod_name);
+		totct += ddebug_apply_class_bitmap(dcp, &inrep, *dcp->bits, mod_name);
 		*dcp->bits = inrep;
 		break;
 	case DD_CLASS_TYPE_LEVEL_NUM:
@@ -706,7 +707,7 @@ static int param_set_dyndbg_module_classes(const char *instr,
 		old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 		new_bits = CLASSMAP_BITMASK(inrep);
 		v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp));
-		totct += ddebug_apply_class_bitmap(dcp, &new_bits, &old_bits, mod_name);
+		totct += ddebug_apply_class_bitmap(dcp, &new_bits, old_bits, mod_name);
 		*dcp->lvl = inrep;
 		break;
 	default:

-- 
2.55.0

[PATCH v6 17/24] dyndbg: replace classmap list with an array-slice

[Jim Cromie]

Classmaps are stored in an elf section/array, but currently are
individually list-linked onto dyndbg's per-module ddebug_table for
operation. This is unnecessary.

Just like dyndbg's descriptors, classmaps are packed in compile order;
so even with many builtin modules employing multiple classmaps, each
modules' maps are packed contiguously, and can be treated as a
array-start-address & array-length.

So this drops the whole list building operation done in
ddebug_attach_module_classes(), and removes the list-head members of
the classmap structs.  The "select-by-modname" condition is reused to
find the start,end of the subrange of classmaps belonging to the module.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
v2: RvB after SoB
---
 include/linux/dynamic_debug.h |  1 -
 lib/dynamic_debug.c           | 65 +++++++++++++++++++++++--------------------
 2 files changed, 35 insertions(+), 31 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index da9e5c35bc43..d164a24dece1 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -87,7 +87,6 @@ enum ddebug_class_map_type {
 };
 
 struct ddebug_class_map {
-	struct list_head link;
 	struct module *mod;
 	const char *mod_name;	/* needed for builtins */
 	const char **class_names;
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 8c3b29904346..6b699ed23d26 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -45,10 +45,11 @@ extern struct ddebug_class_map __start___dyndbg_classes[];
 extern struct ddebug_class_map __stop___dyndbg_classes[];
 
 struct ddebug_table {
-	struct list_head link, maps;
+	struct list_head link;
 	const char *mod_name;
-	unsigned int num_ddebugs;
 	struct _ddebug *ddebugs;
+	struct ddebug_class_map *classes;
+	unsigned int num_ddebugs, num_classes;
 };
 
 struct ddebug_query {
@@ -149,12 +150,13 @@ static void v3pr_info_dq(const struct ddebug_query *query, const char *msg)
 }
 
 static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
-							  const char *class_string, int *class_id)
+							const char *class_string,
+							int *class_id)
 {
 	struct ddebug_class_map *map;
-	int idx;
+	int i, idx;
 
-	list_for_each_entry(map, &dt->maps, link) {
+	for (map = dt->classes, i = 0; i < dt->num_classes; i++, map++) {
 		idx = match_string(map->class_names, map->length, class_string);
 		if (idx >= 0) {
 			*class_id = idx + map->base;
@@ -165,7 +167,6 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons
 	return NULL;
 }
 
-#define __outvar /* filled by callee */
 /*
  * Search the tables for _ddebug's which match the given `query' and
  * apply the `flags' and `mask' to them.  Returns number of matching
@@ -231,7 +232,7 @@ static int ddebug_change(const struct ddebug_query *query,
 	unsigned int nfound = 0;
 	struct flagsbuf fbuf, nbuf;
 	struct ddebug_class_map *map = NULL;
-	int __outvar valid_class;
+	int valid_class;
 
 	/* search for matching ddebugs */
 	mutex_lock(&ddebug_lock);
@@ -1069,9 +1070,10 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
 
 static const char *ddebug_class_name(struct ddebug_iter *iter, struct _ddebug *dp)
 {
-	struct ddebug_class_map *map;
+	struct ddebug_class_map *map = iter->table->classes;
+	int i, nc = iter->table->num_classes;
 
-	list_for_each_entry(map, &iter->table->maps, link)
+	for (i = 0; i < nc; i++, map++)
 		if (class_in_range(dp->class_id, map))
 			return map->class_names[dp->class_id - map->base];
 
@@ -1155,30 +1157,34 @@ static const struct proc_ops proc_fops = {
 	.proc_write = ddebug_proc_write
 };
 
-static void ddebug_attach_module_classes(struct ddebug_table *dt,
-					 struct ddebug_class_map *classes,
-					 int num_classes)
+static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug_info *di)
 {
 	struct ddebug_class_map *cm;
-	int i, j, ct = 0;
+	int i, nc = 0;
 
-	for (cm = classes, i = 0; i < num_classes; i++, cm++) {
+	/*
+	 * Find this module's classmaps in a subrange/wholerange of
+	 * the builtin/modular classmap vector/section.  Save the start
+	 * and length of the subrange at its edges.
+	 */
+	for (cm = di->classes, i = 0; i < di->num_classes; i++, cm++) {
 
 		if (!strcmp(cm->mod_name, dt->mod_name)) {
-
-			v2pr_info("class[%d]: module:%s base:%d len:%d ty:%d\n", i,
-				  cm->mod_name, cm->base, cm->length, cm->map_type);
-
-			for (j = 0; j < cm->length; j++)
-				v3pr_info(" %d: %d %s\n", j + cm->base, j,
-					  cm->class_names[j]);
-
-			list_add(&cm->link, &dt->maps);
-			ct++;
+			if (!nc) {
+				v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n",
+					  i, cm->mod_name, cm->base, cm->length, cm->map_type);
+				dt->classes = cm;
+			}
+			nc++;
+		} else if (nc) {
+			/* end of matching classmaps */
+			break;
 		}
 	}
-	if (ct)
-		vpr_info("module:%s attached %d classes\n", dt->mod_name, ct);
+	if (nc) {
+		dt->num_classes = nc;
+		vpr_info("module:%s attached %d classes\n", dt->mod_name, nc);
+	}
 }
 
 /*
@@ -1210,10 +1216,9 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 	dt->num_ddebugs = di->num_descs;
 
 	INIT_LIST_HEAD(&dt->link);
-	INIT_LIST_HEAD(&dt->maps);
 
 	if (di->classes && di->num_classes)
-		ddebug_attach_module_classes(dt, di->classes, di->num_classes);
+		ddebug_attach_module_classes(dt, di);
 
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
@@ -1326,8 +1331,8 @@ static void ddebug_remove_all_tables(void)
 	mutex_lock(&ddebug_lock);
 	while (!list_empty(&ddebug_tables)) {
 		struct ddebug_table *dt = list_entry(ddebug_tables.next,
-						      struct ddebug_table,
-						      link);
+						     struct ddebug_table,
+						     link);
 		ddebug_table_free(dt);
 	}
 	mutex_unlock(&ddebug_lock);

-- 
2.55.0

[PATCH v6 18/24] dyndbg: macrofy a 2-index for-loop pattern

[Jim Cromie]

dynamic-debug currently has 2 __sections (__dyndbg, __dyndb_classes),
struct _ddebug_info keeps track of them both, with 2 members each:
_vec and _vec#_len.

We need to loop over these sections, with index and record pointer,
making ref to both _vec and _vec_len.  This is already fiddly and
error-prone, and will get worse as we add a 3rd section.

Lets instead embed/abstract the fiddly-ness in the `for_subvec()`
macro, and avoid repeating it going forward.

This is a for-loop macro expander, so it syntactically expects to
precede either a single statement or a { block } of them, and the
usual typeof or do-while-0 tricks are unavailable to fix the
multiple-expansion warning.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
v2: move RvB after SoB
---
 lib/dynamic_debug.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 6b699ed23d26..d99c69b9ad12 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -149,6 +149,20 @@ static void v3pr_info_dq(const struct ddebug_query *query, const char *msg)
 		  query->first_lineno, query->last_lineno, query->class_string);
 }
 
+/*
+ * simplify a repeated for-loop pattern walking N steps in a T _vec
+ * member inside a struct _box.  It expects int i and T *_sp to be
+ * declared in the caller.
+ * @_i:  caller provided counter.
+ * @_sp: cursor into _vec, to examine each item.
+ * @_box: ptr to a struct containing @_vec member
+ * @_vec: name of a member in @_box
+ */
+#define for_subvec(_i, _sp, _box, _vec)			\
+	for ((_i) = 0, (_sp) = (_box)->_vec;		\
+	     (_i) < (_box)->num_##_vec;			\
+	     (_i)++, (_sp)++)		/* { block } */
+
 static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
 							const char *class_string,
 							int *class_id)
@@ -156,7 +170,7 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons
 	struct ddebug_class_map *map;
 	int i, idx;
 
-	for (map = dt->classes, i = 0; i < dt->num_classes; i++, map++) {
+	for_subvec(i, map, dt, classes) {
 		idx = match_string(map->class_names, map->length, class_string);
 		if (idx >= 0) {
 			*class_id = idx + map->base;
@@ -1167,8 +1181,7 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
 	 * the builtin/modular classmap vector/section.  Save the start
 	 * and length of the subrange at its edges.
 	 */
-	for (cm = di->classes, i = 0; i < di->num_classes; i++, cm++) {
-
+	for_subvec(i, cm, di, classes) {
 		if (!strcmp(cm->mod_name, dt->mod_name)) {
 			if (!nc) {
 				v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n",

-- 
2.55.0

[PATCH v6 19/24] dyndbg: pin class param storage to u32

[Jim Cromie]

Currently, `struct ddebug_class_param` uses pointers to `unsigned
long` values which store the state of `bits` and `lvl`, so it changes
sizes depending upon the architecture.  Make it always u32 for
consistency.

The bits field references __drm_debug, which was unsigned int, before
commit f158936b60a7 ("drm: POC drm on dyndbg - use in core, 2 helpers, 3 drivers.")
changed it to unsigned long.  This patch changes it back.

That enlargement was a thinko; although modules can have up to 63
classes, and *could* have all those classes in a single classmap, the
real reason is to support multiple classmaps (with non-overlapping
class-id ranges).

32 bits is a practical limit for a class-param's usability since all
classes are set together with a single write of a hex value; 16 would
be a realistic limit, drm.debug has ~12 classes.

  #> echo 0x0fff > /sys/module/drm/parameters/debug

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v5: u32 for all arches
v4: undo change struct ddebug_class_param to _ddebug_class_param

v3:
fix undefd behavior when classmaps is all 64 bits.
change module_param_named( type-arg from ulong to ullong)
change struct ddebug_class_param to _ddebug_class_param

in drivers/gpu/drm/drm_print.{c,h}
api change later

v2:

patch was "make bits & lvl same size"
but that size was unsigned long, only 32 bits on i386 etc
use u64 for all bits, and %llu %llx

u64-fix

u64-drm-dbg
---
 drivers/gpu/drm/drm_print.c   |  4 ++--
 include/drm/drm_print.h       |  2 +-
 include/linux/dynamic_debug.h |  4 ++--
 lib/dynamic_debug.c           | 35 +++++++++++++++++++----------------
 lib/test_dynamic_debug.c      |  2 +-
 5 files changed, 25 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index ded9461df5f2..711ae6606c6e 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -40,7 +40,7 @@
  * __drm_debug: Enable debug output.
  * Bitmask of DRM_UT_x. See include/drm/drm_print.h for details.
  */
-unsigned long __drm_debug;
+u32 __drm_debug;
 EXPORT_SYMBOL(__drm_debug);
 
 MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n"
@@ -54,7 +54,7 @@ MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug cat
 "\t\tBit 8 (0x100) will enable DP messages (displayport code)");
 
 #if !defined(CONFIG_DRM_USE_DYNAMIC_DEBUG)
-module_param_named(debug, __drm_debug, ulong, 0600);
+module_param_named(debug, __drm_debug, uint, 0600);
 #else
 /* classnames must match vals of enum drm_debug_category */
 DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index ab017b05e175..ed7ce7d7b74c 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -39,7 +39,7 @@ struct drm_device;
 struct seq_file;
 
 /* Do *not* use outside of drm_print.[ch]! */
-extern unsigned long __drm_debug;
+extern u32 __drm_debug;
 
 /**
  * DOC: print
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index d164a24dece1..250b8391cb14 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -105,8 +105,8 @@ struct _ddebug_info {
 
 struct ddebug_class_param {
 	union {
-		unsigned long *bits;
-		unsigned int *lvl;
+		u32 *bits;
+		u32 *lvl;
 	};
 	char flags[8];
 	const struct ddebug_class_map *map;
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index d99c69b9ad12..af05f4ae3b55 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -582,6 +582,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
 		pr_err("query parse failed\n");
 		return -EINVAL;
 	}
+
 	/* actually go and implement the change */
 	nfound = ddebug_change(&query, &modifiers);
 	v3pr_info_dq(&query, nfound ? "applied" : "no-match");
@@ -632,8 +633,7 @@ static int ddebug_exec_queries(char *query, const char *modname)
 
 /* apply a new class-param setting */
 static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
-				     const unsigned long *new_bits,
-				     const unsigned long old_bits,
+				     const u32 *new_bits, const u32 old_bits,
 				     const char *query_modname)
 {
 #define QUERY_SIZE 128
@@ -643,24 +643,27 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 	int bi, ct;
 
 	if (*new_bits != old_bits)
-		v2pr_info("apply bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
+		v2pr_info("apply bitmap: 0x%x to: 0x%x for %s\n", *new_bits,
 			  old_bits, query_modname ?: "'*'");
 
 	for (bi = 0; bi < map->length; bi++) {
-		if (test_bit(bi, new_bits) == test_bit(bi, &old_bits))
+		bool new_b = !!(*new_bits & BIT(bi));
+		bool old_b = !!(old_bits & BIT(bi));
+
+		if (new_b == old_b)
 			continue;
 
 		snprintf(query, QUERY_SIZE, "class %s %c%s", map->class_names[bi],
-			 test_bit(bi, new_bits) ? '+' : '-', dcp->flags);
+			 new_b ? '+' : '-', dcp->flags);
 
 		ct = ddebug_exec_queries(query, query_modname);
 		matches += ct;
 
-		v2pr_info("bit_%d: %d matches on class: %s -> 0x%lx\n", bi,
+		v2pr_info("bit_%d: %d matches on class: %s -> 0x%x\n", bi,
 			  ct, map->class_names[bi], *new_bits);
 	}
 	if (*new_bits != old_bits)
-		v2pr_info("applied bitmap: 0x%lx to: 0x%lx for %s\n", *new_bits,
+		v2pr_info("applied bitmap: 0x%x to: 0x%x for %s\n", *new_bits,
 			  old_bits, query_modname ?: "'*'");
 
 	return matches;
@@ -669,7 +672,7 @@ static int ddebug_apply_class_bitmap(const struct ddebug_class_param *dcp,
 /* stub to later conditionally add "$module." prefix where not already done */
 #define KP_NAME(kp)	kp->name
 
-#define CLASSMAP_BITMASK(width) ((1UL << (width)) - 1)
+#define CLASSMAP_BITMASK(width) ((width) >= 32 ? ~0U : (1U << (width)) - 1)
 
 /**
  * param_set_dyndbg_classes - class FOO >control
@@ -689,10 +692,10 @@ static int param_set_dyndbg_module_classes(const char *instr,
 {
 	const struct ddebug_class_param *dcp = kp->arg;
 	const struct ddebug_class_map *map = dcp->map;
-	unsigned long inrep, new_bits, old_bits;
+	u32 inrep, new_bits, old_bits;
 	int rc, totct = 0;
 
-	rc = kstrtoul(instr, 0, &inrep);
+	rc = kstrtou32(instr, 0, &inrep);
 	if (rc) {
 		int len = strcspn(instr, "\n");
 		pr_err("expecting numeric input, not: %.*s > %s\n",
@@ -704,24 +707,24 @@ static int param_set_dyndbg_module_classes(const char *instr,
 	case DD_CLASS_TYPE_DISJOINT_BITS:
 		/* expect bits. mask and warn if too many */
 		if (inrep & ~CLASSMAP_BITMASK(map->length)) {
-			pr_warn("%s: input: 0x%lx exceeds mask: 0x%lx, masking\n",
+			pr_warn("%s: input: 0x%x exceeds mask: 0x%x, masking\n",
 				KP_NAME(kp), inrep, CLASSMAP_BITMASK(map->length));
 			inrep &= CLASSMAP_BITMASK(map->length);
 		}
-		v2pr_info("bits:0x%lx > %s.%s\n", inrep, mod_name ?: "*", KP_NAME(kp));
+		v2pr_info("bits:0x%x > %s.%s\n", inrep, mod_name ?: "*", KP_NAME(kp));
 		totct += ddebug_apply_class_bitmap(dcp, &inrep, *dcp->bits, mod_name);
 		*dcp->bits = inrep;
 		break;
 	case DD_CLASS_TYPE_LEVEL_NUM:
 		/* input is bitpos, of highest verbosity to be enabled */
 		if (inrep > map->length) {
-			pr_warn("%s: level:%ld exceeds max:%d, clamping\n",
+			pr_warn("%s: level:%u exceeds max:%d, clamping\n",
 				KP_NAME(kp), inrep, map->length);
 			inrep = map->length;
 		}
 		old_bits = CLASSMAP_BITMASK(*dcp->lvl);
 		new_bits = CLASSMAP_BITMASK(inrep);
-		v2pr_info("lvl:%ld bits:0x%lx > %s\n", inrep, new_bits, KP_NAME(kp));
+		v2pr_info("lvl:%u bits:0x%x > %s\n", inrep, new_bits, KP_NAME(kp));
 		totct += ddebug_apply_class_bitmap(dcp, &new_bits, old_bits, mod_name);
 		*dcp->lvl = inrep;
 		break;
@@ -767,9 +770,9 @@ int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
 
 	switch (map->map_type) {
 	case DD_CLASS_TYPE_DISJOINT_BITS:
-		return scnprintf(buffer, PAGE_SIZE, "0x%lx\n", *dcp->bits);
+		return scnprintf(buffer, PAGE_SIZE, "0x%x\n", *dcp->bits);
 	case DD_CLASS_TYPE_LEVEL_NUM:
-		return scnprintf(buffer, PAGE_SIZE, "%d\n", *dcp->lvl);
+		return scnprintf(buffer, PAGE_SIZE, "%u\n", *dcp->lvl);
 	default:
 		return -1;
 	}
diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index 74d183ebf3e0..9e8e028461ad 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -40,7 +40,7 @@ module_param_cb(do_prints, &param_ops_do_prints, NULL, 0600);
  * - tie together sysname, mapname, bitsname, flagsname
  */
 #define DD_SYS_WRAP(_model, _flags)					\
-	static unsigned long bits_##_model;				\
+	static u32 bits_##_model;					\
 	static struct ddebug_class_param _flags##_model = {		\
 		.bits = &bits_##_model,					\
 		.flags = #_flags,					\

-- 
2.55.0

[PATCH v6 20/24] dyndbg,module: make proper substructs in _ddebug_info

[Jim Cromie]

recompose struct _ddebug_info, inserting proper sub-structs.

The struct _ddebug_info has 2 pairs of _vec, num_##_vec fields, for
descs and classes respectively.  for_subvec() makes walking these
vectors less cumbersome, now lets move those field pairs into their
own "vec" structs: _ddebug_descs & _ddebug_class_maps, and re-compose
struct _ddebug_info to contain them cleanly.  This also lets us get
rid of for_subvec()'s num_##_vec paste-up.

Also recompose struct ddebug_table to contain a _ddebug_info.  This
reinforces _ddebug_info's use as a cursor into relevant data for a
builtin module, and access to the full _ddebug state for modules.

NOTES:

Change section names together, for more obvious name pairing.

Invariant: These vectors ref a contiguous subrange of __section memory
in builtin/DATA or in loadable modules via mod->dyndbg_info; with
guaranteed life-time for us.

struct module contains a _ddebug_info field and module/main.c sets it
up, so that gets adjusted rather obviously.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---

v3: squash in section name changes.

v2:

Move RvB after SoB
In structs _ddebug_descs & _ddebug_class_maps, change int length to unsigned int
No use of <0 vals is contemplated.

dyndbg: improve section names

change __dyndbg to __dyndbg_descs
change __dyndbg_classes to __dyndbg_class_maps

this sets up for adding __dyndbg_class_users
---
 drivers/gpu/drm/drm_print.c      |  2 +-
 include/asm-generic/dyndbg.lds.h | 14 +++---
 include/linux/dynamic_debug.h    | 34 +++++++++-----
 kernel/module/main.c             | 12 ++---
 lib/dynamic_debug.c              | 98 ++++++++++++++++++++--------------------
 5 files changed, 86 insertions(+), 74 deletions(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index 711ae6606c6e..da2171186c6b 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -69,7 +69,7 @@ DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
 			"DRM_UT_DP",
 			"DRM_UT_DRMRES");
 
-static struct ddebug_class_param drm_debug_bitmap = {
+static struct _ddebug_class_param drm_debug_bitmap = {
 	.bits = &__drm_debug,
 	.flags = "p",
 	.map = &drm_debug_classes,
diff --git a/include/asm-generic/dyndbg.lds.h b/include/asm-generic/dyndbg.lds.h
index 9d8951bef688..ec661f9f3793 100644
--- a/include/asm-generic/dyndbg.lds.h
+++ b/include/asm-generic/dyndbg.lds.h
@@ -3,16 +3,16 @@
 #define __ASM_GENERIC_DYNDBG_LDS_H
 
 #include <asm-generic/bounded_sections.lds.h>
-#define DYNDBG_SECTIONS()					\
-	BOUNDED_SECTION_BY(__dyndbg, ___dyndbg)			\
-	BOUNDED_SECTION_BY(__dyndbg_classes, ___dyndbg_classes)
+#define DYNDBG_SECTIONS()						\
+	BOUNDED_SECTION_BY(__dyndbg_descs, ___dyndbg_descs)		\
+	BOUNDED_SECTION_BY(__dyndbg_class_maps, ___dyndbg_class_maps)
 
 #define MOD_DYNDBG_SECTIONS()						\
-	__dyndbg 0 : ALIGN(8) {						\
-		KEEP(*(__dyndbg))					\
+	__dyndbg_descs 0 : ALIGN(8) {					\
+		KEEP(*(__dyndbg_descs))					\
 	}								\
-	__dyndbg_classes 0 : ALIGN(8) {					\
-		KEEP(*(__dyndbg_classes))				\
+	__dyndbg_class_maps 0 : ALIGN(8) {				\
+		KEEP(*(__dyndbg_class_maps))				\
 	}
 
 #endif /* __ASM_GENERIC_DYNDBG_LDS_H */
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 250b8391cb14..ca27bdd92693 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -87,7 +87,7 @@ enum ddebug_class_map_type {
 };
 
 struct ddebug_class_map {
-	struct module *mod;
+	struct module *mod;	/* NULL for builtins */
 	const char *mod_name;	/* needed for builtins */
 	const char **class_names;
 	const int length;
@@ -95,12 +95,24 @@ struct ddebug_class_map {
 	enum ddebug_class_map_type map_type;
 };
 
-/* encapsulate linker provided built-in (or module) dyndbg data */
+/*
+ * @_ddebug_info: gathers module/builtin dyndbg_* __sections together.
+ * For builtins, it is used as a cursor, with the inner structs
+ * marking sub-vectors of the builtin __sections in DATA.
+ */
+struct _ddebug_descs {
+	struct _ddebug *start;
+	unsigned int len;
+};
+
+struct _ddebug_class_maps {
+	struct ddebug_class_map *start;
+	unsigned int len;
+};
+
 struct _ddebug_info {
-	struct _ddebug *descs;
-	struct ddebug_class_map *classes;
-	unsigned int num_descs;
-	unsigned int num_classes;
+	struct _ddebug_descs descs;
+	struct _ddebug_class_maps maps;
 };
 
 struct ddebug_class_param {
@@ -121,7 +133,7 @@ struct ddebug_class_param {
 
 /**
  * DECLARE_DYNDBG_CLASSMAP - declare classnames known by a module
- * @_var:   a struct _ddebug_class_map, passed to module_param_cb
+ * @_var:   a struct ddebug_class_map, passed to module_param_cb
  * @_maptype: enum ddebug_class_map_type, chooses bits/verbose
  * @_base:  offset of 1st class-name. splits .class_id space
  * @classes: class-names used to control class'd prdbgs
@@ -129,7 +141,7 @@ struct ddebug_class_param {
 #define DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, ...)		\
 	static const char *_var##_classnames[] = { __VA_ARGS__ };	\
 	static struct ddebug_class_map __aligned(8) __used		\
-		__section("__dyndbg_classes") _var = {			\
+		__section("__dyndbg_class_maps") _var = {			\
 		.mod = THIS_MODULE,					\
 		.mod_name = DDEBUG_MODNAME,				\
 		.base = _base,						\
@@ -169,7 +181,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 
 #define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt)	\
 	static struct _ddebug  __aligned(8)			\
-	__section("__dyndbg") name = {				\
+	__section("__dyndbg_descs") name = {			\
 		.modname = DDEBUG_MODNAME,			\
 		.function = __func__,				\
 		.filename = __FILE__,				\
@@ -256,7 +268,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
  * macro.
  */
 #define _dynamic_func_call_cls(cls, fmt, func, ...)			\
-	__dynamic_func_call_cls(__UNIQUE_ID(ddebug), cls, fmt, func, ##__VA_ARGS__)
+	__dynamic_func_call_cls(__UNIQUE_ID(_ddebug), cls, fmt, func, ##__VA_ARGS__)
 #define _dynamic_func_call(fmt, func, ...)				\
 	_dynamic_func_call_cls(_DPRINTK_CLASS_DFLT, fmt, func, ##__VA_ARGS__)
 
@@ -266,7 +278,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
  * 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,	\
+	__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_cls_no_desc(_DPRINTK_CLASS_DFLT, fmt,	\
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 46dd8d25a605..bd7899a91755 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2774,12 +2774,12 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 		pr_warn("%s: Ignoring obsolete parameters\n", mod->name);
 
 #ifdef CONFIG_DYNAMIC_DEBUG_CORE
-	mod->dyndbg_info.descs = section_objs(info, "__dyndbg",
-					      sizeof(*mod->dyndbg_info.descs),
-					      &mod->dyndbg_info.num_descs);
-	mod->dyndbg_info.classes = section_objs(info, "__dyndbg_classes",
-						sizeof(*mod->dyndbg_info.classes),
-						&mod->dyndbg_info.num_classes);
+	mod->dyndbg_info.descs.start = section_objs(info, "__dyndbg_descs",
+						    sizeof(*mod->dyndbg_info.descs.start),
+						    &mod->dyndbg_info.descs.len);
+	mod->dyndbg_info.maps.start = section_objs(info, "__dyndbg_class_maps",
+						   sizeof(*mod->dyndbg_info.maps.start),
+						   &mod->dyndbg_info.maps.len);
 #endif
 
 	return 0;
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index af05f4ae3b55..5a884cbd6294 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -39,17 +39,15 @@
 
 #include <rdma/ib_verbs.h>
 
-extern struct _ddebug __start___dyndbg[];
-extern struct _ddebug __stop___dyndbg[];
-extern struct ddebug_class_map __start___dyndbg_classes[];
-extern struct ddebug_class_map __stop___dyndbg_classes[];
+extern struct _ddebug __start___dyndbg_descs[];
+extern struct _ddebug __stop___dyndbg_descs[];
+extern struct ddebug_class_map __start___dyndbg_class_maps[];
+extern struct ddebug_class_map __stop___dyndbg_class_maps[];
 
 struct ddebug_table {
 	struct list_head link;
 	const char *mod_name;
-	struct _ddebug *ddebugs;
-	struct ddebug_class_map *classes;
-	unsigned int num_ddebugs, num_classes;
+	struct _ddebug_info info;
 };
 
 struct ddebug_query {
@@ -159,18 +157,18 @@ static void v3pr_info_dq(const struct ddebug_query *query, const char *msg)
  * @_vec: name of a member in @_box
  */
 #define for_subvec(_i, _sp, _box, _vec)			\
-	for ((_i) = 0, (_sp) = (_box)->_vec;		\
-	     (_i) < (_box)->num_##_vec;			\
+	for ((_i) = 0, (_sp) = (_box)->_vec.start;	\
+	     (_i) < (_box)->_vec.len;			\
 	     (_i)++, (_sp)++)		/* { block } */
 
 static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
-							const char *class_string,
-							int *class_id)
+							 const char *class_string,
+							 int *class_id)
 {
 	struct ddebug_class_map *map;
 	int i, idx;
 
-	for_subvec(i, map, dt, classes) {
+	for_subvec(i, map, &dt->info, maps) {
 		idx = match_string(map->class_names, map->length, class_string);
 		if (idx >= 0) {
 			*class_id = idx + map->base;
@@ -267,8 +265,8 @@ static int ddebug_change(const struct ddebug_query *query,
 			valid_class = _DPRINTK_CLASS_DFLT;
 		}
 
-		for (i = 0; i < dt->num_ddebugs; i++) {
-			struct _ddebug *dp = &dt->ddebugs[i];
+		for (i = 0; i < dt->info.descs.len; i++) {
+			struct _ddebug *dp = &dt->info.descs.start[i];
 
 			if (!ddebug_match_desc(query, dp, valid_class))
 				continue;
@@ -1013,8 +1011,8 @@ static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
 	}
 	iter->table = list_entry(ddebug_tables.next,
 				 struct ddebug_table, link);
-	iter->idx = iter->table->num_ddebugs;
-	return &iter->table->ddebugs[--iter->idx];
+	iter->idx = iter->table->info.descs.len;
+	return &iter->table->info.descs.start[--iter->idx];
 }
 
 /*
@@ -1035,10 +1033,10 @@ static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
 		}
 		iter->table = list_entry(iter->table->link.next,
 					 struct ddebug_table, link);
-		iter->idx = iter->table->num_ddebugs;
+		iter->idx = iter->table->info.descs.len;
 		--iter->idx;
 	}
-	return &iter->table->ddebugs[iter->idx];
+	return &iter->table->info.descs.start[iter->idx];
 }
 
 /*
@@ -1082,16 +1080,19 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
 	return dp;
 }
 
-#define class_in_range(class_id, map)					\
-	(class_id >= map->base && class_id < map->base + map->length)
+static bool ddebug_class_in_range(const int class_id, const struct ddebug_class_map *map)
+{
+	return (class_id >= map->base &&
+		class_id < map->base + map->length);
+}
 
-static const char *ddebug_class_name(struct ddebug_iter *iter, struct _ddebug *dp)
+static const char *ddebug_class_name(struct ddebug_table *dt, struct _ddebug *dp)
 {
-	struct ddebug_class_map *map = iter->table->classes;
-	int i, nc = iter->table->num_classes;
+	struct ddebug_class_map *map;
+	int i;
 
-	for (i = 0; i < nc; i++, map++)
-		if (class_in_range(dp->class_id, map))
+	for_subvec(i, map, &dt->info, maps)
+		if (ddebug_class_in_range(dp->class_id, map))
 			return map->class_names[dp->class_id - map->base];
 
 	return NULL;
@@ -1124,7 +1125,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 	seq_putc(m, '"');
 
 	if (dp->class_id != _DPRINTK_CLASS_DFLT) {
-		class = ddebug_class_name(iter, dp);
+		class = ddebug_class_name(iter->table, dp);
 		if (class)
 			seq_printf(m, " class:%s", class);
 		else
@@ -1184,12 +1185,12 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
 	 * the builtin/modular classmap vector/section.  Save the start
 	 * and length of the subrange at its edges.
 	 */
-	for_subvec(i, cm, di, classes) {
+	for_subvec(i, cm, di, maps) {
 		if (!strcmp(cm->mod_name, dt->mod_name)) {
 			if (!nc) {
 				v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n",
 					  i, cm->mod_name, cm->base, cm->length, cm->map_type);
-				dt->classes = cm;
+				dt->info.maps.start = cm;
 			}
 			nc++;
 		} else if (nc) {
@@ -1198,7 +1199,7 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
 		}
 	}
 	if (nc) {
-		dt->num_classes = nc;
+		dt->info.maps.len = nc;
 		vpr_info("module:%s attached %d classes\n", dt->mod_name, nc);
 	}
 }
@@ -1211,10 +1212,10 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 {
 	struct ddebug_table *dt;
 
-	if (!di->num_descs)
+	if (!di->descs.len)
 		return 0;
 
-	v3pr_info("add-module: %s %d sites\n", modname, di->num_descs);
+	v3pr_info("add-module: %s %d sites\n", modname, di->descs.len);
 
 	dt = kzalloc_obj(*dt);
 	if (dt == NULL) {
@@ -1228,19 +1229,18 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 	 * this struct ddebug_table.
 	 */
 	dt->mod_name = modname;
-	dt->ddebugs = di->descs;
-	dt->num_ddebugs = di->num_descs;
+	dt->info = *di;
 
 	INIT_LIST_HEAD(&dt->link);
 
-	if (di->classes && di->num_classes)
+	if (di->maps.len)
 		ddebug_attach_module_classes(dt, di);
 
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
 
-	vpr_info("%3u debug prints in module %s\n", di->num_descs, modname);
+	vpr_info("%3u debug prints in module %s\n", di->descs.len, modname);
 	return 0;
 }
 
@@ -1387,10 +1387,10 @@ static int __init dynamic_debug_init(void)
 	char *cmdline;
 
 	struct _ddebug_info di = {
-		.descs = __start___dyndbg,
-		.classes = __start___dyndbg_classes,
-		.num_descs = __stop___dyndbg - __start___dyndbg,
-		.num_classes = __stop___dyndbg_classes - __start___dyndbg_classes,
+		.descs.start = __start___dyndbg_descs,
+		.maps.start  = __start___dyndbg_class_maps,
+		.descs.len = __stop___dyndbg_descs - __start___dyndbg_descs,
+		.maps.len  = __stop___dyndbg_class_maps - __start___dyndbg_class_maps,
 	};
 
 #ifdef CONFIG_MODULES
@@ -1401,7 +1401,7 @@ static int __init dynamic_debug_init(void)
 	}
 #endif /* CONFIG_MODULES */
 
-	if (&__start___dyndbg == &__stop___dyndbg) {
+	if (&__start___dyndbg_descs == &__stop___dyndbg_descs) {
 		if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
 			pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
 			return 1;
@@ -1411,16 +1411,16 @@ static int __init dynamic_debug_init(void)
 		return 0;
 	}
 
-	iter = iter_mod_start = __start___dyndbg;
+	iter = iter_mod_start = __start___dyndbg_descs;
 	modname = iter->modname;
 	i = mod_sites = mod_ct = 0;
 
-	for (; iter < __stop___dyndbg; iter++, i++, mod_sites++) {
+	for (; iter < __stop___dyndbg_descs; iter++, i++, mod_sites++) {
 
 		if (strcmp(modname, iter->modname)) {
 			mod_ct++;
-			di.num_descs = mod_sites;
-			di.descs = iter_mod_start;
+			di.descs.len = mod_sites;
+			di.descs.start = iter_mod_start;
 			ret = ddebug_add_module(&di, modname);
 			if (ret)
 				goto out_err;
@@ -1430,19 +1430,19 @@ static int __init dynamic_debug_init(void)
 			iter_mod_start = iter;
 		}
 	}
-	di.num_descs = mod_sites;
-	di.descs = iter_mod_start;
+	di.descs.len = mod_sites;
+	di.descs.start = iter_mod_start;
 	ret = ddebug_add_module(&di, modname);
 	if (ret)
 		goto out_err;
 
 	ddebug_init_success = 1;
-	vpr_info("%d prdebugs in %d modules, %d KiB in ddebug tables, %d kiB in __dyndbg section\n",
+	vpr_info("%d prdebugs in %d modules, %d KiB in ddebug tables, %d kiB in __dyndbg_descs section\n",
 		 i, mod_ct, (int)((mod_ct * sizeof(struct ddebug_table)) >> 10),
 		 (int)((i * sizeof(struct _ddebug)) >> 10));
 
-	if (di.num_classes)
-		v2pr_info("  %d builtin ddebug class-maps\n", di.num_classes);
+	if (di.maps.len)
+		v2pr_info("  %d builtin ddebug class-maps\n", di.maps.len);
 
 	/* now that ddebug tables are loaded, process all boot args
 	 * again to find and activate queries given in dyndbg params.

-- 
2.55.0

[PATCH v6 21/24] dyndbg: move mod_name down from struct ddebug_table to _ddebug_info

[Jim Cromie]

struct _ddebug_info already has most of dyndbg's info for a module;
push debug_table.mod_name down into it, finishing the encapsulation.

This allows refactoring several callchains, passing &_ddebug_info
instead of &ddebug_table, and hoisting the "&dt->info" deref up
instead of repeating it thru the callchans

ddebug_table contains a _ddebug_info member, so code with a ptr to a
ddebug_table still have access to mod_name, just now with "->info."
added in.

In static ddebug_add_module(&di), reinforce the cursor-model by
dropping the modname arg, and setting di->mod_name at each caller.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
v2: move RvB after SoB

old-v12
. moved up 1 position in series, ahead of hoist...
---
 include/linux/dynamic_debug.h |  1 +
 lib/dynamic_debug.c           | 52 ++++++++++++++++++++++---------------------
 2 files changed, 28 insertions(+), 25 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index ca27bdd92693..355f2cb11733 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -111,6 +111,7 @@ struct _ddebug_class_maps {
 };
 
 struct _ddebug_info {
+	const char *mod_name;
 	struct _ddebug_descs descs;
 	struct _ddebug_class_maps maps;
 };
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 5a884cbd6294..a9965ec1807a 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -46,7 +46,6 @@ extern struct ddebug_class_map __stop___dyndbg_class_maps[];
 
 struct ddebug_table {
 	struct list_head link;
-	const char *mod_name;
 	struct _ddebug_info info;
 };
 
@@ -249,11 +248,12 @@ static int ddebug_change(const struct ddebug_query *query,
 	/* search for matching ddebugs */
 	mutex_lock(&ddebug_lock);
 	list_for_each_entry(dt, &ddebug_tables, link) {
+		struct _ddebug_info *di = &dt->info;
 
 		/* match against the module name */
 		if (query->module &&
-		    !match_wildcard_hyphen(query->module, dt->mod_name) &&
-		    !match_wildcard_hyphen(query->module, kbasename(dt->mod_name)))
+		    !match_wildcard_hyphen(query->module, di->mod_name) &&
+		    !match_wildcard_hyphen(query->module, kbasename(di->mod_name)))
 			continue;
 
 		if (query->class_string) {
@@ -265,8 +265,8 @@ static int ddebug_change(const struct ddebug_query *query,
 			valid_class = _DPRINTK_CLASS_DFLT;
 		}
 
-		for (i = 0; i < dt->info.descs.len; i++) {
-			struct _ddebug *dp = &dt->info.descs.start[i];
+		for (i = 0; i < di->descs.len; i++) {
+			struct _ddebug *dp = &di->descs.start[i];
 
 			if (!ddebug_match_desc(query, dp, valid_class))
 				continue;
@@ -286,7 +286,7 @@ static int ddebug_change(const struct ddebug_query *query,
 #endif
 			v4pr_info("changed %s:%d [%s]%s %s => %s\n",
 				  trim_prefix(dp->filename), dp->lineno,
-				  dt->mod_name, dp->function,
+				  di->mod_name, dp->function,
 				  ddebug_describe_flags(dp->flags, &fbuf),
 				  ddebug_describe_flags(newflags, &nbuf));
 			dp->flags = newflags;
@@ -1086,12 +1086,12 @@ static bool ddebug_class_in_range(const int class_id, const struct ddebug_class_
 		class_id < map->base + map->length);
 }
 
-static const char *ddebug_class_name(struct ddebug_table *dt, struct _ddebug *dp)
+static const char *ddebug_class_name(struct _ddebug_info *di, struct _ddebug *dp)
 {
 	struct ddebug_class_map *map;
 	int i;
 
-	for_subvec(i, map, &dt->info, maps)
+	for_subvec(i, map, di, maps)
 		if (ddebug_class_in_range(dp->class_id, map))
 			return map->class_names[dp->class_id - map->base];
 
@@ -1119,13 +1119,13 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 
 	seq_printf(m, "%s:%u [%s]%s =%s \"",
 		   trim_prefix(dp->filename), dp->lineno,
-		   iter->table->mod_name, dp->function,
+		   iter->table->info.mod_name, dp->function,
 		   ddebug_describe_flags(dp->flags, &flags));
 	seq_escape_str(m, dp->format, ESCAPE_SPACE, "\t\r\n\"");
 	seq_putc(m, '"');
 
 	if (dp->class_id != _DPRINTK_CLASS_DFLT) {
-		class = ddebug_class_name(iter->table, dp);
+		class = ddebug_class_name(&iter->table->info, dp);
 		if (class)
 			seq_printf(m, " class:%s", class);
 		else
@@ -1186,7 +1186,7 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
 	 * and length of the subrange at its edges.
 	 */
 	for_subvec(i, cm, di, maps) {
-		if (!strcmp(cm->mod_name, dt->mod_name)) {
+		if (!strcmp(cm->mod_name, dt->info.mod_name)) {
 			if (!nc) {
 				v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n",
 					  i, cm->mod_name, cm->base, cm->length, cm->map_type);
@@ -1200,7 +1200,7 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
 	}
 	if (nc) {
 		dt->info.maps.len = nc;
-		vpr_info("module:%s attached %d classes\n", dt->mod_name, nc);
+		vpr_info("module:%s attached %d classes\n", dt->info.mod_name, nc);
 	}
 }
 
@@ -1208,27 +1208,26 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
  * Allocate a new ddebug_table for the given module
  * and add it to the global list.
  */
-static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
+static int ddebug_add_module(struct _ddebug_info *di)
 {
 	struct ddebug_table *dt;
 
 	if (!di->descs.len)
 		return 0;
 
-	v3pr_info("add-module: %s %d sites\n", modname, di->descs.len);
+	v3pr_info("add-module: %s %d sites\n", di->mod_name, di->descs.len);
 
 	dt = kzalloc_obj(*dt);
 	if (dt == NULL) {
-		pr_err("error adding module: %s\n", modname);
+		pr_err("error adding module: %s\n", di->mod_name);
 		return -ENOMEM;
 	}
 	/*
-	 * For built-in modules, name lives in .rodata and is
-	 * immortal. For loaded modules, name points at the name[]
-	 * member of struct module, which lives at least as long as
-	 * this struct ddebug_table.
+	 * For built-in modules, name (as supplied in di by its
+	 * callers) lives in .rodata and is immortal. For loaded
+	 * modules, name points at the name[] member of struct module,
+	 * which lives at least as long as this struct ddebug_table.
 	 */
-	dt->mod_name = modname;
 	dt->info = *di;
 
 	INIT_LIST_HEAD(&dt->link);
@@ -1240,7 +1239,7 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
 	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
 
-	vpr_info("%3u debug prints in module %s\n", di->descs.len, modname);
+	vpr_info("%3u debug prints in module %s\n", di->descs.len, di->mod_name);
 	return 0;
 }
 
@@ -1303,7 +1302,7 @@ static int ddebug_remove_module(const char *mod_name)
 
 	mutex_lock(&ddebug_lock);
 	list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
-		if (dt->mod_name == mod_name) {
+		if (dt->info.mod_name == mod_name) {
 			ddebug_table_free(dt);
 			ret = 0;
 			break;
@@ -1323,7 +1322,8 @@ static int ddebug_module_notify(struct notifier_block *self, unsigned long val,
 
 	switch (val) {
 	case MODULE_STATE_COMING:
-		ret = ddebug_add_module(&mod->dyndbg_info, mod->name);
+		mod->dyndbg_info.mod_name = mod->name;
+		ret = ddebug_add_module(&mod->dyndbg_info);
 		if (ret)
 			WARN(1, "Failed to allocate memory: dyndbg may not work properly.\n");
 		break;
@@ -1421,7 +1421,8 @@ static int __init dynamic_debug_init(void)
 			mod_ct++;
 			di.descs.len = mod_sites;
 			di.descs.start = iter_mod_start;
-			ret = ddebug_add_module(&di, modname);
+			di.mod_name = modname;
+			ret = ddebug_add_module(&di);
 			if (ret)
 				goto out_err;
 
@@ -1432,7 +1433,8 @@ static int __init dynamic_debug_init(void)
 	}
 	di.descs.len = mod_sites;
 	di.descs.start = iter_mod_start;
-	ret = ddebug_add_module(&di, modname);
+	di.mod_name = modname;
+	ret = ddebug_add_module(&di);
 	if (ret)
 		goto out_err;
 

-- 
2.55.0

[PATCH v6 22/24] dyndbg: hoist classmap-filter-by-modname up to ddebug_add_module

[Jim Cromie]

The body of ddebug_attach_module_classes() is just a code-block that
finds the contiguous subrange of classmaps matching on modname, and
saves it into the ddebug_table's info record.

Implement this block in a macro to accommodate different component
vectors in the "box" (as named in the for_subvec macro).  We will
reuse this macro shortly.

And hoist its invocation out of ddebug_attach_module_classes() up into
ddebug_add_module().  This moves the filtering step up closer to
dynamic_debug_init(), which already segments the builtin pr_debug
descriptors on their mod_name boundaries.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
v3: expand block-comment in ddebug_add_module

v2: move RvB after SoB

finish hoist - drop old fn - ddebug_attach_module_classes

the v1 rev left the old ddebug_attach_module_classes in place, but it
is completely redundant now, since it already lost the list-linking
job it was doing.

It was being cut out later in the patchset (in the unsent API
adaptation phase), but for cleaner review, lets excise it now.

OLD all-in-1-series (pre split into reviewable chunks)

v10?- reordered params to match kdoc

v12- refactor/rename: s/dd_mark_vector_subrange/dd_set_module_subrange/

1. Renamed the macro from dd_mark_vector_subrange to
   dd_set_module_subrange to better reflect its purpose of narrowing a
   vector to a module-specific subrange.

2. Simplified the arguments by removing the redundant _dst, as the _di
   pointer already provides access to the target _ddebug_info struct.

3. Refactored for Clarity: Instead of overwriting the struct's start
   pointer while the for_subvec loop is using it to iterate, I
   introduced a temporary __start variable. This avoids the "subtle"
   side effect and makes the logic easier to follow.

4. Updated Documentation: Improved the comment block to explicitly
   state that the macro scans for the first match and counts
   contiguous elements.

fiuxp
---
 lib/dynamic_debug.c | 80 ++++++++++++++++++++++++++++-------------------------
 1 file changed, 43 insertions(+), 37 deletions(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index a9965ec1807a..1d5b9f68791a 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1175,34 +1175,34 @@ static const struct proc_ops proc_fops = {
 	.proc_write = ddebug_proc_write
 };
 
-static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug_info *di)
-{
-	struct ddebug_class_map *cm;
-	int i, nc = 0;
-
-	/*
-	 * Find this module's classmaps in a subrange/wholerange of
-	 * the builtin/modular classmap vector/section.  Save the start
-	 * and length of the subrange at its edges.
-	 */
-	for_subvec(i, cm, di, maps) {
-		if (!strcmp(cm->mod_name, dt->info.mod_name)) {
-			if (!nc) {
-				v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n",
-					  i, cm->mod_name, cm->base, cm->length, cm->map_type);
-				dt->info.maps.start = cm;
-			}
-			nc++;
-		} else if (nc) {
-			/* end of matching classmaps */
-			break;
-		}
-	}
-	if (nc) {
-		dt->info.maps.len = nc;
-		vpr_info("module:%s attached %d classes\n", dt->info.mod_name, nc);
-	}
-}
+/*
+ * dd_set_module_subrange - find matching subrange of classmaps
+ * @_i:   caller-provided index var
+ * @_sp:  cursor into @_vec
+ * @_di:  pointer to the struct _ddebug_info to be narrowed
+ * @_vec: name of the vector member (must have .start and .len)
+ *
+ * Narrow a _ddebug_info's vector (@_vec) of classmaps to the
+ * contiguous subrange of elements where ->mod_name matches
+ * @__di->mod_name.  This is primarily for builtins, loadable modules
+ * have only their classmaps, and dont need this sub-selection.
+ */
+#define dd_set_module_subrange(_i, _sp, _di, _vec) ({			\
+	struct _ddebug_info *__di = (_di);				\
+	typeof(__di->_vec.start) __start = NULL;			\
+	int __nc = 0;							\
+	for_subvec(_i, _sp, __di, _vec) {				\
+		if (!strcmp((_sp)->mod_name, __di->mod_name)) {		\
+			if (!__nc++)					\
+				__start = (_sp);			\
+		} else if (__nc) {					\
+			break; /* end of consecutive matches */		\
+		}							\
+	}								\
+	if (__nc)							\
+		__di->_vec.start = __start;				\
+	__di->_vec.len = __nc;						\
+})
 
 /*
  * Allocate a new ddebug_table for the given module
@@ -1211,6 +1211,8 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
 static int ddebug_add_module(struct _ddebug_info *di)
 {
 	struct ddebug_table *dt;
+	struct ddebug_class_map *cm;
+	int i;
 
 	if (!di->descs.len)
 		return 0;
@@ -1223,17 +1225,21 @@ static int ddebug_add_module(struct _ddebug_info *di)
 		return -ENOMEM;
 	}
 	/*
-	 * For built-in modules, name (as supplied in di by its
-	 * callers) lives in .rodata and is immortal. For loaded
-	 * modules, name points at the name[] member of struct module,
-	 * which lives at least as long as this struct ddebug_table.
+	 * For built-in modules, di is a partial cursor into the
+	 * builtin dyndbg data; the descriptors are the subrange
+	 * matching the modname, but the classmaps are the full set.
+	 * We find and set the relevant subrange of classmaps here.
+	 *
+	 * The modname string is in .rodata, the descriptors and
+	 * classmaps are in writable .data. All are immortal.
+	 *
+	 * For loaded modules, mod_name points at the name[] member
+	 * of struct module, and the descriptors and classmaps point
+	 * at the module's ELF sections; all have lifetimes matching
+	 * the module's presence.
 	 */
 	dt->info = *di;
-
-	INIT_LIST_HEAD(&dt->link);
-
-	if (di->maps.len)
-		ddebug_attach_module_classes(dt, di);
+	dd_set_module_subrange(i, cm, &dt->info, maps);
 
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);

-- 
2.55.0

[PATCH v6 23/24] dyndbg: change __dynamic_func_call_cls* macros into expressions

[Jim Cromie]

The Xe driver's XE_IOCTL_DBG macro calls drm_dbg() from inside an if
(expression).  This breaks when CONFIG_DRM_USE_DYNAMIC_DEBUG=y because
the invoked macro has a do-while-0 wrapper, and is not an expression.

   if (cond && (drm_dbg("expr-form"),1)) {
      ... do some more stuff
   }

Fix for this usage by changing __dynamic_func_call_cls{,_no_desc}
macros into expressions, by replacing the do-while-0s with a ({ })
wrapper.  In the common usage, the trailing ';' converts the
expression into a statement.

   drm_dbg("statement form");

Additionally, change the dynamic_hex_dump() fallback macro (used when
CONFIG_DYNAMIC_DEBUG is disabled) from a do-while-0 statement into a
statement expression returning 0.  This ensures that the fallback form
of dynamic_hex_dump() behaves consistently with its enabled form, and
makes it safe for use in conditional expression contexts.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---

v5: also convert dynamic_hex_dump() stub

v2:

fix statement-expressions to return 0 (not void) like their respective fallbacks

   1. Add 0; to __dynamic_func_call_cls
   2. Add 0; to __dynamic_func_call_cls_no_desc
   3. Convert the disabled fallback of dynamic_hex_dump from do { ... } while(0) to ({ ... 0; })

move RvB after SoB
---
 include/linux/dynamic_debug.h | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 355f2cb11733..8822f9a3605f 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -238,24 +238,26 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
  * (|_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_func_call_cls(id, cls, fmt, func, ...) ({	\
 	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);	\
 	if (DYNAMIC_DEBUG_BRANCH(id)) {				\
 		func(&id, ##__VA_ARGS__);			\
 		__dynamic_dump_stack(id);			\
 	}							\
-} while (0)
+	0; /* match no_printk return value */			\
+})
 #define __dynamic_func_call(id, fmt, func, ...)				\
 	__dynamic_func_call_cls(id, _DPRINTK_CLASS_DFLT, fmt,		\
 				func, ##__VA_ARGS__)
 
-#define __dynamic_func_call_cls_no_desc(id, cls, fmt, func, ...) do {	\
+#define __dynamic_func_call_cls_no_desc(id, cls, fmt, func, ...) ({	\
 	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);		\
 	if (DYNAMIC_DEBUG_BRANCH(id)) {					\
 		func(__VA_ARGS__);					\
 		__dynamic_dump_stack(id);				\
 	}								\
-} while (0)
+	0; /* match no_printk return value */				\
+})
 #define __dynamic_func_call_no_desc(id, fmt, func, ...)			\
 	__dynamic_func_call_cls_no_desc(id, _DPRINTK_CLASS_DFLT,	\
 					fmt, func, ##__VA_ARGS__)
@@ -335,10 +337,12 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 	dev_no_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__)
 #define dynamic_hex_dump(prefix_str, prefix_type, rowsize,		\
 			 groupsize, buf, len, ascii)			\
-	do { if (0)							\
+({									\
+	if (0)								\
 		print_hex_dump(KERN_DEBUG, prefix_str, prefix_type,	\
-				rowsize, groupsize, buf, len, ascii);	\
-	} while (0)
+			       rowsize, groupsize, buf, len, ascii);	\
+	0;								\
+})
 
 #endif /* CONFIG_DYNAMIC_DEBUG || (CONFIG_DYNAMIC_DEBUG_CORE && DYNAMIC_DEBUG_MODULE) */
 

-- 
2.55.0

[PATCH v6 24/24] dyndbg-API: replace DECLARE_DYNDBG_CLASSMAP

[Jim Cromie]

commit aad0214f3026 ("dyndbg: add DECLARE_DYNDBG_CLASSMAP macro")

DECLARE_DYNDBG_CLASSMAP() has a design error; its usage fails a
basic K&R rule: "define once, refer many times".

When CONFIG_DRM_USE_DYNAMIC_DEBUG=y, it is used across DRM core &
drivers; each invocation allocates/inits the classmap understood by
that module.  They *all* must match for the DRM modules to respond
consistently when drm.debug categories are enabled.  This is at least
a maintenance hassle.

Worse, its the root cause of the CONFIG_DRM_USE_DYNAMIC_DEBUG=Y
regression; its use in both core & drivers obfuscates the 2 roles,
muddling the design, yielding an incomplete initialization when
modprobing drivers:

1st drm.ko loads, and dyndbg initializes its drm.debug callsites, then
a drm-driver loads, but too late for the drm.debug enablement.

And that led to:
commit bb2ff6c27bc9 ("drm: Disable dynamic debug as broken")

So retire it, replace with 2 macros:
  DYNAMIC_DEBUG_CLASSMAP_DEFINE - invoked once from core - drm.ko
  DYNAMIC_DEBUG_CLASSMAP_USE*   - from all drm drivers and helpers.
  NB: name-space de-noise

DYNAMIC_DEBUG_CLASSMAP_DEFINE: this reworks DECLARE_DYNDBG_CLASSMAP,
basically by dropping the static qualifier on the classmap, and
exporting it instead.

DYNAMIC_DEBUG_CLASSMAP_USE: then refers to the exported var by name:
  used from drivers, helper-mods
  lets us drop the repetitive "classname" declarations
  fixes 2nd-defn problem
  creates a ddebug_class_user record in new __dyndbg_class_users section
  new section is scanned similarly

DECLARE_DYNDBG_CLASSMAP is preserved temporarily, to decouple DRM
adaptation work and avoid compile errs before its done.

The DEFINE,USE distinction, and the separate classmap-use record,
allows dyndbg to initialize the driver's & helper's drm.debug
callsites separately after each is modprobed.  Basically, the classmap
initial scan is repeated for classmap-users.

Data Structure and Header Changes:
  - Introduce 'struct ddebug_class_user':
    Contains the user-module-name and a pointer to the classmap definition.
    It records a drm-driver's use of a classmap in a new section,
    allowing runtime lookup.
  - Update 'struct ddebug_info' with two new fields:
    'class_users' and 'num_class_users'. These are initialized by
    dynamic_debug_init() for built-ins, and by load_info() in
    kernel/module/main.c for loadable modules.
  - Update 'vmlinux.lds.h':
    Add a new BOUNDED_SECTION for '__dyndbg_class_users' to define
    __start and __stop C symbols for the section.
  - Rename the '__dyndbg_classes' section to '__dyndbg_class_maps'.

Execution Engine Changes:
  - ddebug_add_module():
    Refactor and split ddebug_attach_module_classes() into
    debug_apply_class_maps() and ddebug_apply_class_users(), both of
    which call ddebug_apply_params().
  - ddebug_apply_params():
    Scans a module's or built-in's kernel-parameters, calling
    ddebug_match_apply_kparam() for each to locate parameters wired
    to a classmap.
  - ddebug_match_apply_kparam():
    Verifies that the kernel-parameter ops belong to dyndbg, ensuring
    the target parameter is valid.

Fixes: aad0214f3026 ("dyndbg: add DECLARE_DYNDBG_CLASSMAP macro")
cc: linux-doc@vger.kernel.org
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
v5:

old, overwrought commit-msg:

dyndbg's existing __dyndbg_classes[] section does:

. catalogs the module's classmaps
. tells dyndbg about them, allowing >control
. DYNAMIC_DEBUG_CLASSMAP_DEFINE creates section records.
. we rename it to: __dyndbg_class_maps[]

this patch adds __dyndbg_class_users[] section:

. catalogs users of classmap definitions from elsewhere
. authorizes dyndbg to >control user's class'd prdbgs
. DYNAMIC_DEBUG_CLASSMAP_USE() creates section records.

Now ddebug_add_module(etal) can handle classmap-uses similar to (and
after) classmaps; when a dependent module is loaded, if it has
classmap-uses (to a classmap-def in another module), that module's
kernel params are scanned to find if it has a kparam that is wired to
dyndbg's param-ops, and whose classmap is the one being ref'd.

To support this, there are a few data/header changes:

new struct ddebug_class_user
  contains: user-module-name, &classmap-defn
  it records drm-driver's use of a classmap in the section, allowing lookup

struct ddebug_info gets 2 new fields for the new sections:
  class_users, num_class_users.
  set by dynamic_debug_init() for builtins.
  or by kernel/module/main:load_info() for loadable modules.

vmlinux.lds.h: Add a new BOUNDED_SECTION for __dyndbg_class_users.
this creates start,stop C symbol-names for the section.

Callchain Details:

dynamic_debug.c: 2 changes from ddebug_add_module() & ddebug_change():

ddebug_add_module():

ddebug_attach_module_classes() is reworked/renamed/split into
debug_apply_class_maps(), ddebug_apply_class_users(), which both call
ddebug_apply_params().

ddebug_apply_params(new fn):

It scans module's/builtin kernel-params, calls ddebug_match_apply_kparam
for each to find any params/sysfs-nodes which may be wired to a classmap.

ddebug_match_apply_kparam(new fn):

1st, it tests the kernel-param.ops is dyndbg's; this guarantees that
the attached arg is a struct ddebug_class_param, which has a ref to
the param's state, and to the classmap defining the param's handling.

2nd, it requires that the classmap ref'd by the kparam is the one
we've been called for; modules can use many separate classmaps (as
test_dynamic_debug does).

Then apply the "parent" kparam's setting to the dependent module,
using ddebug_apply_class_bitmap().

ddebug_change(and callees) also gets adjustments:

ddebug_find_valid_class(): This does a search over the module's
classmaps, looking for the class FOO echo'd to >control.  So now it
searches over __dyndbg_class_users[] after __dyndbg_classes[].

ddebug_class_name(): return class-names for defined OR used classes.

test_dynamic_debug.c, test_dynamic_debug_submod.c:

This demonstrates the 2 types of classmaps & sysfs-params, following
the 4-part recipe:

0. define an enum for the classmap's class_ids
   drm.debug gives us DRM_UT_<*> (aka <T>)
   multiple classmaps in a module(s) must share 0-62 classid space.

1. DYNAMIC_DEBUG_CLASSMAP_DEFINE(classmap_name, .. "<T>")
   names the classes, maps them to consecutive class-ids.
   convention here is stringified ENUM_SYMBOLS
   these become API/ABI if 2 is done.

2. DYNAMIC_DEBUG_CLASSMAP_PARAM* (classmap_name)
   adds a controlling kparam to the class

3. DYNAMIC_DEBUG_CLASSMAP_USE(classmap_name)
   for subsystem/group/drivers to use extern created by 1.

Move all the enum declarations together, to better explain how they
share the 0..62 class-id space available to a module (non-overlapping
subranges).

reorg macros 2,3 by name.  This gives a tabular format, making it easy
to see the pattern of repetition, and the points of change.

And extend the test to replicate the 2-module (parent & dependent)
scenario which caused the CONFIG_DRM_USE_DYNAMIC_DEBUG=y regression
seen in drm & drivers.

The _submod.c is a 2-line file: #define _SUBMOD, #include parent.

This gives identical complements of prdbgs in parent & _submod, and
thus identical print behavior when all of: >control, >params, and
parent->_submod propagation are working correctly.

It also puts all the parent/_submod declarations together in the same
source; the new ifdef _SUBMOD block invokes DYNAMIC_DEBUG_CLASSMAP_USE
for the 2 test-interfaces.  I think this is clearer.

These 2 modules are both tristate, allowing 3 super/sub combos: Y/Y,
Y/M, M/M (not N/Y, since this is disallowed by dependence).

Y/Y, Y/M testing once exposed a missing __align(8) in the _METADATA
macro, which M/M didn't see, probably because the module-loader memory
placement constrained it from misalignment.

---
v2: RvB after SoB

old-v?
replace di with &dt->info, since di becomes stale
fix dd_mark_vector_subrange macro param ordering to match kdoc
s/base/offset/ in _ddebug_class_user, to reduce later churn

-v12 - squash in _USE_ and refinements.

A: dyndbg: add DYNAMIC_DEBUG_CLASSMAP_USE_(dd_class_name, offset)

Allow a module to use 2 classmaps together that would otherwise have a
class_id range conflict.

Suppose a drm-driver does:

  DYNAMIC_DEBUG_CLASSMAP_USE(drm_debug_classes);
  DYNAMIC_DEBUG_CLASSMAP_USE(drm_accel_xfer_debug);

If (for some reason) drm-accel cannot define their constants to avoid
DRM's drm_debug_category 0..10 reservations, we would have a conflict
with reserved-ids.

In this case a driver needing to use both would _USE_ one of them with
an offset to avoid the conflict.  This will handle most forseeable
cases; perhaps a 3-X-3 of classmap-defns X classmap-users would get
too awkward and fiddly.

B: dyndbg: refine DYNAMIC_DEBUG_CLASSMAP_USE_ macro

The struct _ddebug_class_user _varname construct is needlessly
permissive; it has a static qualifier, and a unique name.  Together,
these allow a module to have 2 or more _USE(foo)s, which is contrary
to its purpose, and therefore potentially confusing.

So drop the unique name, and the static qualifier, and replace it with
an extern pre-declaration.  Construct the name by pasting together the
_var (which is the name of the exported ddebug_class_map), and
__KBUILD_MODNAME (which is the user module name).  This allows only a
single USE() reference to the exported record, which is all that is
required.
---
 include/asm-generic/dyndbg.lds.h |   6 +-
 include/linux/dynamic_debug.h    | 165 +++++++++++++++++++++++++++++++++++----
 kernel/module/main.c             |   3 +
 lib/Kconfig.debug                |  24 ++++--
 lib/Makefile                     |   3 +
 lib/dynamic_debug.c              | 140 ++++++++++++++++++++++++++++++---
 lib/test_dynamic_debug.c         | 119 ++++++++++++++++++++++------
 lib/test_dynamic_debug_submod.c  |  14 ++++
 8 files changed, 415 insertions(+), 59 deletions(-)

diff --git a/include/asm-generic/dyndbg.lds.h b/include/asm-generic/dyndbg.lds.h
index ec661f9f3793..0ffc9cde4377 100644
--- a/include/asm-generic/dyndbg.lds.h
+++ b/include/asm-generic/dyndbg.lds.h
@@ -5,7 +5,8 @@
 #include <asm-generic/bounded_sections.lds.h>
 #define DYNDBG_SECTIONS()						\
 	BOUNDED_SECTION_BY(__dyndbg_descs, ___dyndbg_descs)		\
-	BOUNDED_SECTION_BY(__dyndbg_class_maps, ___dyndbg_class_maps)
+	BOUNDED_SECTION_BY(__dyndbg_class_maps, ___dyndbg_class_maps)	\
+	BOUNDED_SECTION_BY(__dyndbg_class_users, ___dyndbg_class_users)
 
 #define MOD_DYNDBG_SECTIONS()						\
 	__dyndbg_descs 0 : ALIGN(8) {					\
@@ -13,6 +14,9 @@
 	}								\
 	__dyndbg_class_maps 0 : ALIGN(8) {				\
 		KEEP(*(__dyndbg_class_maps))				\
+	}								\
+	__dyndbg_class_users 0 : ALIGN(8) {				\
+		KEEP(*(__dyndbg_class_users))				\
 	}
 
 #endif /* __ASM_GENERIC_DYNDBG_LDS_H */
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 8822f9a3605f..48a8e6145d51 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -86,19 +86,30 @@ enum ddebug_class_map_type {
 	 */
 };
 
+/*
+ * map @class_names 0..N to consecutive constants starting at @base.
+ */
 struct ddebug_class_map {
-	struct module *mod;	/* NULL for builtins */
-	const char *mod_name;	/* needed for builtins */
+	const struct module *mod;	/* NULL for builtins */
+	const char *mod_name;		/* needed for builtins */
 	const char **class_names;
 	const int length;
 	const int base;		/* index of 1st .class_id, allows split/shared space */
 	enum ddebug_class_map_type map_type;
-};
+} __aligned(8);
+
+struct ddebug_class_user {
+	char *mod_name;
+	struct ddebug_class_map *map;
+	const int offset;	/* offset from map->base */
+} __aligned(8);
 
 /*
- * @_ddebug_info: gathers module/builtin dyndbg_* __sections together.
+ * @_ddebug_info: gathers module/builtin __dyndbg_<T> __sections
+ * together, each is a vec_<T>: a struct { struct T start[], int len }.
+ *
  * For builtins, it is used as a cursor, with the inner structs
- * marking sub-vectors of the builtin __sections in DATA.
+ * marking sub-vectors of the builtin __sections in DATA_DATA
  */
 struct _ddebug_descs {
 	struct _ddebug *start;
@@ -110,10 +121,16 @@ struct _ddebug_class_maps {
 	unsigned int len;
 };
 
+struct _ddebug_class_users {
+	struct ddebug_class_user *start;
+	int len;
+};
+
 struct _ddebug_info {
 	const char *mod_name;
 	struct _ddebug_descs descs;
 	struct _ddebug_class_maps maps;
+	struct _ddebug_class_users users;
 };
 
 struct ddebug_class_param {
@@ -132,25 +149,132 @@ struct ddebug_class_param {
 #if defined(CONFIG_DYNAMIC_DEBUG) || \
 	(defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
 
+/*
+ * dyndbg classmaps is modelled closely upon drm.debug:
+ *
+ *  1. run-time control via sysfs node (api/abi)
+ *  2. each bit 0..N controls a single "category"
+ *  3. a pr_debug can have only 1 category, not several.
+ *  4. "kind" is a compile-time constant: 0..N or BIT() thereof
+ *  5. macro impls - give compile-time resolution or fail.
+ *
+ * dyndbg classmaps design axioms/constraints:
+ *
+ *  . optimizing compilers use 1-5 above, so preserve them.
+ *  . classmaps.class_id *is* the category.
+ *  . classmap definers/users are modules.
+ *  . every user wants 0..N
+ *  . 0..N exposes as ABI
+ *  . no 1 use-case wants N > 32, 16 is more usable
+ *  . N <= 64 in *all* cases
+ *  . modules/subsystems make category/classmap decisions
+ *  . ie an enum: DRM has DRM_UT_CORE..DRM_UT_DRMRES
+ *  . some categories are exposed to user: ABI
+ *  . making modules change their numbering is bogus, avoid if possible
+ *
+ * We can solve for all these at once:
+ *  A: map class-names to a .class_id range at compile-time
+ *  B: allow only "class NAME" changes to class'd callsites at run-time
+ *  C: users/modules must manage 0..62 hardcoded .class_id range limit.
+ *  D: existing pr_debugs get CLASS_DFLT=63
+ *
+ * By mapping class-names at >control to class-ids underneath, and
+ * responding only to class-names DEFINEd or USEd by the module, we
+ * can private-ize the class-id, and adjust class'd pr_debugs only by
+ * their names.
+ *
+ * This give us:
+ *  E: class_ids without classnames are unreachable
+ *  F: user modules opt-in by DEFINEing a classmap and/or USEing another
+ *
+ * Multi-classmap modules/groups are supported, if the classmaps share
+ * the class_id space [0..62] without overlap/conflict.
+ *
+ * NOTE: Due to the integer class_id, this api cannot disallow these:
+ * __pr_debug_cls(0, "fake CORE msg");  works only if a classmap maps 0.
+ * __pr_debug_cls(22, "no such class"); compiles but is not reachable
+ */
+
 /**
- * DECLARE_DYNDBG_CLASSMAP - declare classnames known by a module
- * @_var:   a struct ddebug_class_map, passed to module_param_cb
- * @_maptype: enum ddebug_class_map_type, chooses bits/verbose
- * @_base:  offset of 1st class-name. splits .class_id space
- * @classes: class-names used to control class'd prdbgs
+ * DYNAMIC_DEBUG_CLASSMAP_DEFINE - define debug classes used by a module.
+ * @_var:   name of the classmap, exported for other modules coordinated use.
+ * @_mapty: enum ddebug_class_map_type: 0:DISJOINT - independent, 1:LEVEL - v2>v1
+ * @_base:  reserve N classids starting at _base, to split 0..62 classid space
+ * @classes: names of the N classes.
+ *
+ * This tells dyndbg what class_ids the module is using: _base..+N, by
+ * mapping names onto them.  This qualifies "class NAME" >controls on
+ * the defining module, ignoring unknown names.
+ */
+#define DYNAMIC_DEBUG_CLASSMAP_DEFINE(_var, _mapty, _base, ...)		\
+	static const char *_var##_classnames[] = { __VA_ARGS__ };	\
+	extern struct ddebug_class_map _var;				\
+	struct ddebug_class_map __aligned(8) __used			\
+		__section("__dyndbg_class_maps") _var = {		\
+		.mod = THIS_MODULE,					\
+		.mod_name = DDEBUG_MODNAME,				\
+		.base = (_base),					\
+		.map_type = (_mapty),					\
+		.length = ARRAY_SIZE(_var##_classnames),		\
+		.class_names = _var##_classnames,			\
+	};								\
+	EXPORT_SYMBOL(_var)
+
+/*
+ * XXX: keep this until DRM adapts to use the DEFINE/USE api, it
+ * differs from DYNAMIC_DEBUG_CLASSMAP_DEFINE by the lack of the
+ * extern/EXPORT on the struct init, and cascading thinkos.
  */
 #define DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, ...)		\
 	static const char *_var##_classnames[] = { __VA_ARGS__ };	\
 	static struct ddebug_class_map __aligned(8) __used		\
-		__section("__dyndbg_class_maps") _var = {			\
+		__section("__dyndbg_class_maps") _var = {		\
 		.mod = THIS_MODULE,					\
 		.mod_name = DDEBUG_MODNAME,				\
 		.base = _base,						\
 		.map_type = _maptype,					\
-		.length = (sizeof(_var##_classnames) / sizeof(_var##_classnames[0])), \
+		.length = __DDEBUG_ARRAY_SIZE(_var##_classnames),	\
 		.class_names = _var##_classnames,			\
 	}
 
+/**
+ * DYNAMIC_DEBUG_CLASSMAP_USE - refer to a classmap, DEFINEd elsewhere.
+ * @_var: name of the exported classmap var
+ *
+ * This tells dyndbg that the module has prdbgs with classids defined
+ * in the named classmap.  This qualifies "class NAME" >controls on
+ * the user module, and ignores unknown names. This is a wrapper for
+ * DYNAMIC_DEBUG_CLASSMAP_USE_() with a base offset of 0.
+ */
+#define DYNAMIC_DEBUG_CLASSMAP_USE(_var) \
+	DYNAMIC_DEBUG_CLASSMAP_USE_(_var, 0)
+
+/**
+ * DYNAMIC_DEBUG_CLASSMAP_USE_ - refer to a classmap with a manual offset.
+ * @_var:   name of the exported classmap var to use.
+ * @_offset:  an integer offset to add to the class IDs of the used map.
+ *
+ * This is an extended version of DYNAMIC_DEBUG_CLASSMAP_USE(). It should
+ * only be used to resolve class ID conflicts when a module uses multiple
+ * classmaps that have overlapping ID ranges.
+ *
+ * The final class IDs for the used map will be calculated as:
+ * original_map_base + class_index + @_offset.
+ */
+#define DYNAMIC_DEBUG_CLASSMAP_USE_(_var, _offset)			\
+	extern struct ddebug_class_map _var;				\
+	static_assert((_offset) >= 0 && (_offset) < _DPRINTK_CLASS_DFLT, \
+		      "classmap use offset must be in 0..62");          \
+	extern struct ddebug_class_user __aligned(8)			\
+		__PASTE(_var ## _, __KBUILD_MODNAME);			\
+	struct ddebug_class_user __aligned(8) __used			\
+		__section("__dyndbg_class_users")			\
+		__PASTE(_var ## _, __KBUILD_MODNAME) = {		\
+		.mod_name = DDEBUG_MODNAME,				\
+		.map = &(_var),						\
+		.offset = _offset					\
+	}
+
 extern __printf(2, 3)
 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...);
 
@@ -314,12 +438,18 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 				   KERN_DEBUG, prefix_str, prefix_type,	\
 				   rowsize, groupsize, buf, len, ascii)
 
-/* for test only, generally expect drm.debug style macro wrappers */
-#define __pr_debug_cls(cls, fmt, ...) do {			\
+/*
+ * This is the "model" class variant of pr_debug.  It is not really
+ * intended for direct use; I'd encourage DRM-style drm_dbg_<T>
+ * macros for the interface, along with an enum for the <T>
+ *
+ * __printf(2, 3) would apply.
+ */
+#define __pr_debug_cls(cls, fmt, ...) ({			\
 	BUILD_BUG_ON_MSG(!__builtin_constant_p(cls),		\
 			 "expecting constant class int/enum");	\
 	dynamic_pr_debug_cls(cls, fmt, ##__VA_ARGS__);		\
-	} while (0)
+})
 
 #else /* !(CONFIG_DYNAMIC_DEBUG || (CONFIG_DYNAMIC_DEBUG_CORE && DYNAMIC_DEBUG_MODULE)) */
 
@@ -327,6 +457,8 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 #include <linux/errno.h>
 #include <linux/printk.h>
 
+#define DYNAMIC_DEBUG_CLASSMAP_DEFINE(_var, _mapty, _base, ...)
+#define DYNAMIC_DEBUG_CLASSMAP_USE(_var)
 #define DEFINE_DYNAMIC_DEBUG_METADATA(name, fmt)
 #define DYNAMIC_DEBUG_BRANCH(descriptor) false
 #define DECLARE_DYNDBG_CLASSMAP(...)
@@ -375,8 +507,7 @@ static inline int param_set_dyndbg_classes(const char *instr, const struct kerne
 static inline int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
 { return 0; }
 
-#endif
-
+#endif /* !CONFIG_DYNAMIC_DEBUG_CORE */
 
 extern const struct kernel_param_ops param_ops_dyndbg_classes;
 
diff --git a/kernel/module/main.c b/kernel/module/main.c
index bd7899a91755..6414608b5c3c 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2780,6 +2780,9 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 	mod->dyndbg_info.maps.start = section_objs(info, "__dyndbg_class_maps",
 						   sizeof(*mod->dyndbg_info.maps.start),
 						   &mod->dyndbg_info.maps.len);
+	mod->dyndbg_info.users.start = section_objs(info, "__dyndbg_class_users",
+						   sizeof(*mod->dyndbg_info.users.start),
+						   &mod->dyndbg_info.users.len);
 #endif
 
 	return 0;
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1244dcac2294..1bcce12cd875 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -3152,12 +3152,26 @@ config TEST_STATIC_KEYS
 	  If unsure, say N.
 
 config TEST_DYNAMIC_DEBUG
-	tristate "Test DYNAMIC_DEBUG"
-	depends on DYNAMIC_DEBUG
+	tristate "Build test-dynamic-debug module"
+	depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
 	help
-	  This module registers a tracer callback to count enabled
-	  pr_debugs in a 'do_debugging' function, then alters their
-	  enablements, calls the function, and compares counts.
+	  This module exercises/demonstrates dyndbg's classmap API, by
+	  creating 2 classes: a DISJOINT classmap (supporting DRM.debug)
+	  and a LEVELS/VERBOSE classmap (like verbose2 > verbose1).
+
+	  If unsure, say N.
+
+config TEST_DYNAMIC_DEBUG_SUBMOD
+	tristate "Build test-dynamic-debug submodule"
+	default m
+	depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
+	depends on TEST_DYNAMIC_DEBUG
+	help
+	  This sub-module uses a classmap defined and exported by the
+	  parent module, recapitulating drm & driver's shared use of
+	  drm.debug to control enabled debug-categories.
+	  It is tristate, independent of parent, to allow testing all
+	  proper combinations of parent=y/m submod=y/m.
 
 	  If unsure, say N.
 
diff --git a/lib/Makefile b/lib/Makefile
index 7f75cc6edf94..75d4c5e596e9 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -84,6 +84,7 @@ obj-$(CONFIG_TEST_RHASHTABLE) += test_rhashtable.o
 obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
 obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
 obj-$(CONFIG_TEST_DYNAMIC_DEBUG) += test_dynamic_debug.o
+obj-$(CONFIG_TEST_DYNAMIC_DEBUG_SUBMOD) += test_dynamic_debug_submod.o
 
 obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
 ifeq ($(CONFIG_CC_IS_CLANG)$(CONFIG_KASAN),yy)
@@ -206,6 +207,8 @@ obj-$(CONFIG_ARCH_NEED_CMPXCHG_1_EMU) += cmpxchg-emu.o
 obj-$(CONFIG_DYNAMIC_DEBUG_CORE) += dynamic_debug.o
 #ensure exported functions have prototypes
 CFLAGS_dynamic_debug.o := -DDYNAMIC_DEBUG_MODULE
+CFLAGS_test_dynamic_debug.o := -DDYNAMIC_DEBUG_MODULE
+CFLAGS_test_dynamic_debug_submod.o := -DDYNAMIC_DEBUG_MODULE
 
 obj-$(CONFIG_SYMBOLIC_ERRNAME) += errname.o
 
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 1d5b9f68791a..358e603a3173 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -29,6 +29,7 @@
 #include <linux/string_helpers.h>
 #include <linux/uaccess.h>
 #include <linux/dynamic_debug.h>
+
 #include <linux/debugfs.h>
 #include <linux/slab.h>
 #include <linux/jump_label.h>
@@ -43,6 +44,8 @@ extern struct _ddebug __start___dyndbg_descs[];
 extern struct _ddebug __stop___dyndbg_descs[];
 extern struct ddebug_class_map __start___dyndbg_class_maps[];
 extern struct ddebug_class_map __stop___dyndbg_class_maps[];
+extern struct ddebug_class_user __start___dyndbg_class_users[];
+extern struct ddebug_class_user __stop___dyndbg_class_users[];
 
 struct ddebug_table {
 	struct list_head link;
@@ -160,20 +163,39 @@ static void v3pr_info_dq(const struct ddebug_query *query, const char *msg)
 	     (_i) < (_box)->_vec.len;			\
 	     (_i)++, (_sp)++)		/* { block } */
 
-static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
-							 const char *class_string,
+#define v2pr_di_info(di_p, msg_p, ...)					\
+({									\
+	struct _ddebug_info const *_di = di_p;				\
+	v2pr_info(msg_p "module:%s nd:%d nc:%d nu:%d\n", ##__VA_ARGS__, \
+		  _di->mod_name, _di->descs.len, _di->maps.len,         \
+		  _di->users.len);                                      \
+})
+
+static struct ddebug_class_map *ddebug_find_valid_class(struct _ddebug_info const *di,
+							 const char *query_class,
 							 int *class_id)
 {
 	struct ddebug_class_map *map;
+	struct ddebug_class_user *cli;
 	int i, idx;
 
-	for_subvec(i, map, &dt->info, maps) {
-		idx = match_string(map->class_names, map->length, class_string);
+	for_subvec(i, map, di, maps) {
+		idx = match_string(map->class_names, map->length, query_class);
 		if (idx >= 0) {
+			v2pr_di_info(di, "good-class: %s.%s ", map->mod_name, query_class);
 			*class_id = idx + map->base;
 			return map;
 		}
 	}
+	for_subvec(i, cli, di, users) {
+		idx = match_string(cli->map->class_names, cli->map->length, query_class);
+		if (idx >= 0) {
+			v2pr_di_info(di, "class-ref: %s -> %s.%s ",
+				    cli->mod_name, cli->map->mod_name, query_class);
+			*class_id = idx + cli->map->base - cli->offset;
+			return cli->map;
+		}
+	}
 	*class_id = -ENOENT;
 	return NULL;
 }
@@ -234,8 +256,7 @@ static bool ddebug_match_desc(const struct ddebug_query *query,
 	return true;
 }
 
-static int ddebug_change(const struct ddebug_query *query,
-			 struct flag_settings *modifiers)
+static int ddebug_change(const struct ddebug_query *query, struct flag_settings *modifiers)
 {
 	int i;
 	struct ddebug_table *dt;
@@ -257,7 +278,8 @@ static int ddebug_change(const struct ddebug_query *query,
 			continue;
 
 		if (query->class_string) {
-			map = ddebug_find_valid_class(dt, query->class_string, &valid_class);
+			map = ddebug_find_valid_class(&dt->info, query->class_string,
+						      &valid_class);
 			if (!map)
 				continue;
 		} else {
@@ -590,7 +612,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
 
 /* handle multiple queries in query string, continue on error, return
    last error or number of matching callsites.  Module name is either
-   in param (for boot arg) or perhaps in query string.
+   in the modname arg (for boot args) or perhaps in query string.
 */
 static int ddebug_exec_queries(char *query, const char *modname)
 {
@@ -737,7 +759,7 @@ static int param_set_dyndbg_module_classes(const char *instr,
 /**
  * param_set_dyndbg_classes - classmap kparam setter
  * @instr: string echo>d to sysfs, input depends on map_type
- * @kp:    kp->arg has state: bits/lvl, map, map_type
+ * @kp:    kp->arg has state: bits/lvl, classmap, map_type
  *
  * enable/disable all class'd pr_debugs in the classmap. For LEVEL
  * map-types, enforce * relative levels by bitpos.
@@ -774,6 +796,7 @@ int param_get_dyndbg_classes(char *buffer, const struct kernel_param *kp)
 	default:
 		return -1;
 	}
+	return 0;
 }
 EXPORT_SYMBOL(param_get_dyndbg_classes);
 
@@ -1089,12 +1112,17 @@ static bool ddebug_class_in_range(const int class_id, const struct ddebug_class_
 static const char *ddebug_class_name(struct _ddebug_info *di, struct _ddebug *dp)
 {
 	struct ddebug_class_map *map;
+	struct ddebug_class_user *cli;
 	int i;
 
 	for_subvec(i, map, di, maps)
 		if (ddebug_class_in_range(dp->class_id, map))
 			return map->class_names[dp->class_id - map->base];
 
+	for_subvec(i, cli, di, users)
+		if (ddebug_class_in_range(dp->class_id, cli->map))
+			return cli->map->class_names[dp->class_id - cli->map->base - cli->offset];
+
 	return NULL;
 }
 
@@ -1175,6 +1203,87 @@ static const struct proc_ops proc_fops = {
 	.proc_write = ddebug_proc_write
 };
 
+#define vpr_cm_info(cm_p, msg_fmt, ...) ({				\
+	struct ddebug_class_map const *_cm = cm_p;			\
+	v2pr_info(msg_fmt "%s [%d..%d] %s..%s\n", ##__VA_ARGS__,	\
+		  _cm->mod_name, _cm->base, _cm->base + _cm->length,	\
+		  _cm->class_names[0], _cm->class_names[_cm->length - 1]); \
+	})
+
+static void ddebug_sync_classbits(const struct kernel_param *kp, const char *modname)
+{
+	const struct ddebug_class_param *dcp = kp->arg;
+
+	/* clamp initial bitvec, mask off hi-bits */
+	if (*dcp->bits & ~CLASSMAP_BITMASK(dcp->map->length)) {
+		*dcp->bits &= CLASSMAP_BITMASK(dcp->map->length);
+		v2pr_info("preset classbits: %x\n", *dcp->bits);
+	}
+	/* force class'd prdbgs (in USEr module) to match (DEFINEr module) class-param */
+	ddebug_apply_class_bitmap(dcp, dcp->bits, ~0, modname);
+	ddebug_apply_class_bitmap(dcp, dcp->bits, 0, modname);
+}
+
+static void ddebug_match_apply_kparam(const struct kernel_param *kp,
+				      const struct ddebug_class_map *map,
+				      const char *mod_name)
+{
+	struct ddebug_class_param *dcp;
+
+	if (kp->ops != &param_ops_dyndbg_classes)
+		return;
+
+	dcp = (struct ddebug_class_param *)kp->arg;
+
+	if (dcp) {
+		v2pr_info(" kp:%s.%s =0x%x", mod_name, kp->name, *dcp->bits);
+		vpr_cm_info(map, " %s maps ", mod_name);
+		ddebug_sync_classbits(kp, mod_name);
+	}
+}
+
+static void ddebug_apply_params(const struct ddebug_class_map *cm, const char *mod_name)
+{
+	const struct kernel_param *kp;
+#if IS_ENABLED(CONFIG_MODULES)
+	int i;
+
+	if (cm->mod) {
+		vpr_cm_info(cm, "loaded classmap: %s ", mod_name);
+		/* ifdef protects the cm->mod->kp deref */
+		for (i = 0, kp = cm->mod->kp; i < cm->mod->num_kp; i++, kp++)
+			ddebug_match_apply_kparam(kp, cm, mod_name);
+	}
+#endif
+	if (!cm->mod) {
+		vpr_cm_info(cm, "builtin classmap: %s ", mod_name);
+		for (kp = __start___param; kp < __stop___param; kp++)
+			ddebug_match_apply_kparam(kp, cm, mod_name);
+	}
+}
+
+static void ddebug_apply_class_maps(const struct _ddebug_info *di)
+{
+	struct ddebug_class_map *cm;
+	int i;
+
+	for_subvec(i, cm, di, maps)
+		ddebug_apply_params(cm, cm->mod_name);
+
+	v2pr_di_info(di, "attached %d class-maps to ", i);
+}
+
+static void ddebug_apply_class_users(const struct _ddebug_info *di)
+{
+	struct ddebug_class_user *cli;
+	int i;
+
+	for_subvec(i, cli, di, users)
+		ddebug_apply_params(cli->map, cli->mod_name);
+
+	v2pr_di_info(di, "attached %d class-users to ", i);
+}
+
 /*
  * dd_set_module_subrange - find matching subrange of classmaps
  * @_i:   caller-provided index var
@@ -1212,6 +1321,7 @@ static int ddebug_add_module(struct _ddebug_info *di)
 {
 	struct ddebug_table *dt;
 	struct ddebug_class_map *cm;
+	struct ddebug_class_user *cli;
 	int i;
 
 	if (!di->descs.len)
@@ -1224,6 +1334,7 @@ static int ddebug_add_module(struct _ddebug_info *di)
 		pr_err("error adding module: %s\n", di->mod_name);
 		return -ENOMEM;
 	}
+	INIT_LIST_HEAD(&dt->link);
 	/*
 	 * For built-in modules, di is a partial cursor into the
 	 * builtin dyndbg data; the descriptors are the subrange
@@ -1240,12 +1351,19 @@ static int ddebug_add_module(struct _ddebug_info *di)
 	 */
 	dt->info = *di;
 	dd_set_module_subrange(i, cm, &dt->info, maps);
+	dd_set_module_subrange(i, cli, &dt->info, users);
+
+	if (dt->info.maps.len)
+		ddebug_apply_class_maps(&dt->info);
+	if (dt->info.users.len)
+		ddebug_apply_class_users(&dt->info);
 
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
 
-	vpr_info("%3u debug prints in module %s\n", di->descs.len, di->mod_name);
+	vpr_info("%3u debug prints in module %s\n",
+		 dt->info.descs.len, dt->info.mod_name);
 	return 0;
 }
 
@@ -1395,8 +1513,10 @@ static int __init dynamic_debug_init(void)
 	struct _ddebug_info di = {
 		.descs.start = __start___dyndbg_descs,
 		.maps.start  = __start___dyndbg_class_maps,
+		.users.start = __start___dyndbg_class_users,
 		.descs.len = __stop___dyndbg_descs - __start___dyndbg_descs,
 		.maps.len  = __stop___dyndbg_class_maps - __start___dyndbg_class_maps,
+		.users.len = __stop___dyndbg_class_users - __start___dyndbg_class_users,
 	};
 
 #ifdef CONFIG_MODULES
diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index 9e8e028461ad..512bac3179ad 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -6,11 +6,30 @@
  *      Jim Cromie	<jim.cromie@gmail.com>
  */
 
-#define pr_fmt(fmt) "test_dd: " fmt
+/*
+ * This file is built 2x, also making test_dynamic_debug_submod.ko,
+ * whose 2-line src file #includes this file.  This gives us a _submod
+ * clone with identical pr_debugs, without further maintenance.
+ *
+ * If things are working properly, they should operate identically
+ * when printed or adjusted by >control.  This eases visual perusal of
+ * the logs, and simplifies testing, by easing the proper accounting
+ * of expectations.
+ *
+ * It also puts both halves of the subsystem _DEFINE & _USE use case
+ * together, and integrates the common ENUM providing both class_ids
+ * and class-names to both _DEFINErs and _USERs.  I think this makes
+ * the usage clearer.
+ */
+#if defined(TEST_DYNAMIC_DEBUG_SUBMOD)
+  #define pr_fmt(fmt) "test_dd_submod: " fmt
+#else
+  #define pr_fmt(fmt) "test_dd: " fmt
+#endif
 
 #include <linux/module.h>
 
-/* run tests by reading or writing sysfs node: do_prints */
+/* re-gen output by reading or writing sysfs node: do_prints */
 
 static void do_prints(void); /* device under test */
 static int param_set_do_prints(const char *instr, const struct kernel_param *kp)
@@ -39,14 +58,36 @@ module_param_cb(do_prints, &param_ops_do_prints, NULL, 0600);
  * Additionally, here:
  * - tie together sysname, mapname, bitsname, flagsname
  */
-#define DD_SYS_WRAP(_model, _flags)					\
-	static u32 bits_##_model;					\
-	static struct ddebug_class_param _flags##_model = {		\
+#define DYNAMIC_DEBUG_CLASSMAP_PARAM_(_model, _flags, _init)		\
+	static u32 bits_##_model = _init;				\
+	static struct ddebug_class_param _flags##_##_model = {		\
 		.bits = &bits_##_model,					\
 		.flags = #_flags,					\
 		.map = &map_##_model,					\
 	};								\
-	module_param_cb(_flags##_##_model, &param_ops_dyndbg_classes, &_flags##_model, 0600)
+	module_param_cb(_flags##_##_model, &param_ops_dyndbg_classes,	\
+			&_flags##_##_model, 0600)
+#ifdef DEBUG
+#define DYNAMIC_DEBUG_CLASSMAP_PARAM(_model, _flags)		\
+	DYNAMIC_DEBUG_CLASSMAP_PARAM_(_model, _flags, ~0)
+#else
+#define DYNAMIC_DEBUG_CLASSMAP_PARAM(_model, _flags)		\
+	DYNAMIC_DEBUG_CLASSMAP_PARAM_(_model, _flags, 0)
+#endif
+
+/*
+ * Demonstrate/test DISJOINT & LEVEL typed classmaps with a sys-param.
+ *
+ * To comport with DRM debug-category (an int), classmaps map names to
+ * ids (also an int).  So a classmap starts with an enum; DRM has enum
+ * debug_category: with DRM_UT_<CORE,DRIVER,KMS,etc>.  We use the enum
+ * values as class-ids, and stringified enum-symbols as classnames.
+ *
+ * Modules with multiple CLASSMAPS must have enums with distinct
+ * value-ranges, as arranged below with explicit enum_sym = X inits.
+ * To clarify this sharing, declare the 2 enums now, for the 2
+ * different classmap types
+ */
 
 /* numeric input, independent bits */
 enum cat_disjoint_bits {
@@ -60,26 +101,51 @@ enum cat_disjoint_bits {
 	D2_LEASE,
 	D2_DP,
 	D2_DRMRES };
-DECLARE_DYNDBG_CLASSMAP(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS, 0,
-			"D2_CORE",
-			"D2_DRIVER",
-			"D2_KMS",
-			"D2_PRIME",
-			"D2_ATOMIC",
-			"D2_VBL",
-			"D2_STATE",
-			"D2_LEASE",
-			"D2_DP",
-			"D2_DRMRES");
-DD_SYS_WRAP(disjoint_bits, p);
-DD_SYS_WRAP(disjoint_bits, T);
-
-/* numeric verbosity, V2 > V1 related */
-enum cat_level_num { V0 = 14, V1, V2, V3, V4, V5, V6, V7 };
-DECLARE_DYNDBG_CLASSMAP(map_level_num, DD_CLASS_TYPE_LEVEL_NUM, 14,
-		       "V0", "V1", "V2", "V3", "V4", "V5", "V6", "V7");
-DD_SYS_WRAP(level_num, p);
-DD_SYS_WRAP(level_num, T);
+
+/* numeric verbosity, V2 > V1 related.  V0 is > D2_DRMRES */
+enum cat_level_num { V0 = 16, V1, V2, V3, V4, V5, V6, V7 };
+
+/* recapitulate DRM's multi-classmap setup */
+#if !defined(TEST_DYNAMIC_DEBUG_SUBMOD)
+/*
+ * In single user, or parent / coordinator (drm.ko) modules, define
+ * classmaps on the client enums above, and then declares the PARAMS
+ * ref'g the classmaps.  Each is exported.
+ */
+DYNAMIC_DEBUG_CLASSMAP_DEFINE(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS,
+			      D2_CORE,
+			      "D2_CORE",
+			      "D2_DRIVER",
+			      "D2_KMS",
+			      "D2_PRIME",
+			      "D2_ATOMIC",
+			      "D2_VBL",
+			      "D2_STATE",
+			      "D2_LEASE",
+			      "D2_DP",
+			      "D2_DRMRES");
+
+DYNAMIC_DEBUG_CLASSMAP_DEFINE(map_level_num, DD_CLASS_TYPE_LEVEL_NUM,
+			      V0, "V0", "V1", "V2", "V3", "V4", "V5", "V6", "V7");
+
+/*
+ * now add the sysfs-params
+ */
+
+DYNAMIC_DEBUG_CLASSMAP_PARAM(disjoint_bits, p);
+DYNAMIC_DEBUG_CLASSMAP_PARAM(level_num, p);
+
+#else /* TEST_DYNAMIC_DEBUG_SUBMOD */
+
+/*
+ * in submod/drm-drivers, use the classmaps defined in top/parent
+ * module above.
+ */
+
+DYNAMIC_DEBUG_CLASSMAP_USE(map_disjoint_bits);
+DYNAMIC_DEBUG_CLASSMAP_USE(map_level_num);
+
+#endif
 
 /* stand-in for all pr_debug etc */
 #define prdbg(SYM) __pr_debug_cls(SYM, #SYM " msg\n")
@@ -115,6 +181,7 @@ static void do_levels(void)
 
 static void do_prints(void)
 {
+	pr_debug("do_prints:\n");
 	do_cats();
 	do_levels();
 }
diff --git a/lib/test_dynamic_debug_submod.c b/lib/test_dynamic_debug_submod.c
new file mode 100644
index 000000000000..672aabf40160
--- /dev/null
+++ b/lib/test_dynamic_debug_submod.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Kernel module for testing dynamic_debug
+ *
+ * Authors:
+ *      Jim Cromie	<jim.cromie@gmail.com>
+ */
+
+/*
+ * clone the parent, inherit all the properties, for consistency and
+ * simpler accounting in test expectations.
+ */
+#define TEST_DYNAMIC_DEBUG_SUBMOD
+#include "test_dynamic_debug.c"

-- 
2.55.0