This series has cleanups and refactors in preparation for an API
change needed to fix a regression in DRM when it uses dyndbg
classmaps. I split these out for easier review, and to stay under
gmail's 500/day message limit.
Whats here:
. factor ddebug_match_desc out from ddebug_change
separate selecting from altering
. add stub macro for DECLARE_DYNDBG_CLASSMAP
for cleaner patches later
. reword class unknown to class _UNKNOWN_
a more greppable error announcement
. API remove DD_CLASS_TYPE_ DISJOINT LEVEL _NAME
these are unused, just extra untested code.
. drop NUM_TYPE_ARGS - just use ~ARRAY_SIZE
. bump num tokens in a query cmd from 9 to 15
with class keyword, can have 13 words in a query
. reduce verbose debug clutter
7 log-lines to 4, with same info
. lib parser add match_wildcard_hyphen for underscore/hypen equivalence
"module kvm-intel" is same as "module kvm_intel"
. dynamic_debug use KBUILD_MODFILE for unique builtin names
disambiguate init/main from kernel/module/main
. refactor param_set_dyndbg_classes and below
improve selectivity of callchain underneath
. tighten fn sig of ddebug_apply_class_bitmap
make more args const
. replace classmap list with an array slice
section records are directly usable from the array
. macrofy a 2 index for loop pattern - DRY
. pin class param storage to u32
avoid param size ambiguity across arches
this also changes __drm_debug from long unsigned to u32.
. module make proper substructs in _ddebug_info
its just cleaner
. move mod_name down from struct ddebug_table to _ddebug_info
makes mod_name more available where its needed
. hoist classmap filter-by-modname up to ddebug_add_module
closer to where its done for pr-debug descriptors
. change __dynamic_func_call_cls macros into expressions
Xe driver uses it inside an if (cond), do-while-0 cant sit there.
"user visible" changes:
The KBUILD_MODFILE derived name appears in dynamic_debug/control, so
[main] changes to [init/main] etc. The query parser is adjusted so
that "module main" still selects all of the former [main] modules.
It is user visible, but not a behavior change.
If a coder calls __pr_debug_cls(5, "...") but does not register a
classmap for it, that callsite will display in dynamic_debug/control
as "class:_UNKNOWN_ _id:5", not "class unknown, _id:5" as previously.
This is an error case, and has never been seen in the wild.
---
Changes in v5:
moves KBUILD_MODFILE ahead of array-slice, to address sashiko
complaints which were fixed later 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.
Changes in v3:
fix some (not all) of sashiko's complaints.
Changes in v2:
https://lore.kernel.org/lkml/[email protected]/
V2 addressed most of sashiko's feedback on V1:
https://sashiko.dev/#/patchset/20260504-dd-cleanups-2-v1-0-6fdd24040642%40gmail.com
---
Jim Cromie (18):
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
Documentation/admin-guide/dynamic-debug-howto.rst | 42 +-
drivers/gpu/drm/drm_print.c | 6 +-
include/asm-generic/dyndbg.lds.h | 14 +-
include/drm/drm_print.h | 2 +-
include/linux/dynamic_debug.h | 130 +++---
include/linux/parser.h | 1 +
kernel/module/main.c | 12 +-
lib/dynamic_debug.c | 494 +++++++++++-----------
lib/parser.c | 58 ++-
lib/test_dynamic_debug.c | 28 +-
10 files changed, 397 insertions(+), 390 deletions(-)
---
base-commit: 4dcdecc52686a3fbd4545e86fc711fdcd15f09cb
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 <[email protected]>
