kernel/linux.git/include/linux/dynamic_debug.h, branch v6.6.132

dyndbg: add source filename to prefix

2023-08-04T13:28:41+00:00

Printing the line number without the file is of limited usefulness. Knowing the filename also makes it also easier to relate the logged information to the controlfile. Example: # modprobe test_dynamic_debug # echo 'file test_dynamic_debug.c =pfsl' > /proc/dynamic_debug/control # echo 1 > /sys/module/test_dynamic_debug/parameters/do_prints # dmesg | tail -2 [ 71.802212] do_cats:lib/test_dynamic_debug.c:103: test_dd: doing categories [ 71.802227] do_levels:lib/test_dynamic_debug.c:123: test_dd: doing levels Signed-off-by: Thomas Weißschuh Acked-by: Jim Cromie Acked-by: Jason Baron Reviewed-by: Luis Chamberlain Link: https://lore.kernel.org/r/20230709-dyndbg-filename-v2-3-fd83beef0925@weissschuh.net Signed-off-by: Greg Kroah-Hartman

dyndbg: cleanup dynamic usage in ib_srp.c

2023-03-19T20:25:20+00:00

Currently, in dynamic_debug.h we only provide DEFINE_DYNAMIC_DEBUG_METADATA() and DYNAMIC_DEBUG_BRANCH() definitions if CONFIG_DYNAMIC_CORE is enabled. Thus, drivers such as infiniband srp (see: drivers/infiniband/ulp/srp/ib_srp.c) must provide their own definitions for !CONFIG_DYNAMIC_CORE. Thus, let's move this !CONFIG_DYNAMIC_CORE case into dynamic_debug.h. However, the dynamic debug interfaces should really only be defined if CONFIG_DYNAMIC_DEBUG is set or CONFIG_DYNAMIC_CORE is set along with DYNAMIC_DEBUG_MODULE, (see: Documentation/admin-guide/dynamic-debug-howto.rst). Thus, the undefined case becomes: !((CONFIG_DYNAMIC_DEBUG || (CONFIG_DYNAMIC_CORE && DYNAMIC_DEBUG_MODULE)). With those changes in place, we can remove the !CONFIG_DYNAMIC_CORE case from ib_srp.c This change was prompted by a build breakeage in ib_srp.c stemming from the inclusion of dynamic_debug.h unconditionally in module.h, due to commit 7deabd674988 ("dyndbg: use the module notifier callbacks"). In that case, if we have CONFIG_DYNAMIC_CORE=y and CONFIG_DYNAMIC_DEBUG=n then the definitions for DEFINE_DYNAMIC_DEBUG_METADATA() and DYNAMIC_DEBUG_BRANCH() are defined once in ib_srp.c and then again in the dynamic_debug.h. This had been working prior to the above referenced commit because dynamic_debug.h was only pulled into ib_srp.c conditinally via printk.h if CONFIG_DYNAMIC_DEBUG was set. Also, the exported functions in lib/dynamic_debug.c itself may not have a prototype if CONFIG_DYNAMIC_DEBUG=n and CONFIG_DYNAMIC_CORE=y. This would trigger the -Wmissing-prototypes warning. The exported functions are behind (include/linux/dynamic_debug.h): if defined(CONFIG_DYNAMIC_DEBUG) || \ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) Thus, by adding -DDYNAMIC_CONFIG_MODULE to the lib/Makefile we can ensure that the exported functions have a prototype in all cases, since lib/dynamic_debug.c is built whenever CONFIG_DYNAMIC_DEBUG_CORE=y. Fixes: 7deabd674988 ("dyndbg: use the module notifier callbacks") Reported-by: kernel test robot Link: https://lore.kernel.org/oe-kbuild-all/202303071444.sIbZTDCy-lkp@intel.com/ Signed-off-by: Jason Baron [mcgrof: adjust commit log, and remove urldefense from URL] Signed-off-by: Luis Chamberlain

dyndbg: use the module notifier callbacks

2023-03-09T20:58:36+00:00

Bring dynamic debug in line with other subsystems by using the module notifier callbacks. This results in a net decrease in core module code. Additionally, Jim Cromie has a new dynamic debug classmap feature, which requires that jump labels be initialized prior to dynamic debug. Specifically, the new feature toggles a jump label from the existing dynamic_debug_setup() function. However, this does not currently work properly, because jump labels are initialized via the 'module_notify_list' notifier chain, which is invoked after the current call to dynamic_debug_setup(). Thus, this patch ensures that jump labels are initialized prior to dynamic debug by setting the dynamic debug notifier priority to 0, while jump labels have the higher priority of 1. Tested by Jim using his new test case, and I've verfied the correct printing via: # modprobe test_dynamic_debug dyndbg. Link: https://lore.kernel.org/lkml/20230113193016.749791-21-jim.cromie@gmail.com/ Reported-by: kernel test robot Link: https://lore.kernel.org/oe-kbuild-all/202302190427.9iIK2NfJ-lkp@intel.com/ Tested-by: Jim Cromie Reviewed-by: Vincenzo Palazzo Cc: Peter Zijlstra CC: Jim Cromie Cc: Luis Chamberlain Cc: Greg Kroah-Hartman Signed-off-by: Jason Baron Signed-off-by: Luis Chamberlain

dyndbg: add drm.debug style (drm/parameters/debug) bitmap support

2022-09-07T15:04:49+00:00

Add kernel_param_ops and callbacks to use a class-map to validate and apply input to a sysfs-node, which allows users to control classes defined in that class-map. This supports uses like: echo 0x3 > /sys/module/drm/parameters/debug IE add these: - int param_set_dyndbg_classes() - int param_get_dyndbg_classes() - struct kernel_param_ops param_ops_dyndbg_classes Following the model of kernel/params.c STANDARD_PARAM_DEFS, these are non-static and exported. This might be unnecessary here. get/set use an augmented kernel_param; the arg refs a new struct ddebug_class_param, which contains: - A ptr to user's state-store; a union of &ulong for drm.debug, &int for nouveau level debug. By ref'g the client's bit-state _var, code coordinates with existing code (like drm_debug_enabled) which uses it, so existing/remaining calls can work unchanged. Changing drm.debug to a ulong allows use of BIT() etc. - FLAGS: dyndbg.flags toggled by changes to bitmap. Usually just "p". - MAP: a pointer to struct ddebug_classes_map, which maps those class-names to .class_ids 0..N that the module is using. This class-map is declared & initialized by DECLARE_DYNDBG_CLASSMAP. - map-type: 4 enums DD_CLASS_TYPE_* select 2 input forms and 2 meanings. numeric input: DD_CLASS_TYPE_DISJOINT_BITS integer input, independent bits. ie: drm.debug DD_CLASS_TYPE_LEVEL_NUM integer input, 0..N levels classnames-list (comma separated) input: DD_CLASS_TYPE_DISJOINT_NAMES each name affects a bit, others preserved DD_CLASS_TYPE_LEVEL_NAMES names have level meanings, like kern_levels.h _NAMES - comma-separated classnames (with optional +-) _NUM - numeric input, 0-N expected _BITS - numeric input, 0x1F bitmap form expected _DISJOINT - bits are independent _LEVEL - (x /sys/module/drm/parameters/debug_catnames A naive _LEVEL_NAMES use, with one class, that sets all in the class-map according to (x /sys/module/test_dynamic_debug/parameters/p_level_names : problem solved echo -L1 > /sys/module/test_dynamic_debug/parameters/p_level_names Note this artifact: : this is same as prev cmd (due to +/-) echo L0 > /sys/module/test_dynamic_debug/parameters/p_level_names : this is "even-more" off, but same wo __pr_debug_class(L0, ".."). echo -L0 > /sys/module/test_dynamic_debug/parameters/p_level_names A stress-test/make-work usage (kid toggling a light switch): echo +L7,L0,L7,L0,L7,L0,L7,L0,L7,L0,L7,L0,L7 \ > /sys/module/test_dynamic_debug/parameters/p_level_names ddebug_apply_class_bitmap(): inside-fn, works on bitmaps, receives new-bits, finds diffs vs client-bitvector holding "current" state, and issues exec_query to commit the adjustment. param_set_dyndbg_classes(): interface fn, sends _NAMES to param_set_dyndbg_classnames() and returns, falls thru to handle _BITS, _NUM internally, and calls ddebug_apply_class_bitmap(). Finishes by updating state. param_set_dyndbg_classnames(): handles classnames-list in loop, calls ddebug_apply_class_bitmap for each, then updates state. NOTES: _LEVEL_ is overlay on _DISJOINT_; inputs are converted to a bitmask, by the callbacks. IOW this is possible, and possibly confusing: echo class V3 +p > control echo class V1 -p > control IMO thats ok, relative verbosity is an interface property. _LEVEL_NUM maps still need class-names, even though the names are not usable at the sysfs interface (unlike with _NAMES style). The names are the only way to >control the classes. - It must have a "V0" name, something below "V1" to turn "V1" off. __pr_debug_cls(V0,..) is printk, don't do that. - "class names" is required at the >control interface. - relative levels are not enforced at >control _LEVEL_NAMES bear +/- signs, which alters the on-bit-pos by 1. IOW, +L2 means L0,L1,L2, and -L2 means just L0,L1. This kinda spoils the readback fidelity, since the L0 bit gets turned on by any use of any L*, except "-L0". All the interface uncertainty here pertains to the _NAMES features. Nobody has actually asked for this, so its practical (if a little tedious) to split it out. Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-21-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman

kernel/module: add __dyndbg_classes section

2022-09-07T15:04:49+00:00

Add __dyndbg_classes section, using __dyndbg as a model. Use it: vmlinux.lds.h: KEEP the new section, which also silences orphan section warning on loadable modules. Add (__start_/__stop_)__dyndbg_classes linker symbols for the c externs (below). kernel/module/main.c: - fill new fields in find_module_sections(), using section_objs() - extend callchain prototypes to pass classes, length load_module(): pass new info to dynamic_debug_setup() dynamic_debug_setup(): new params, pass through to ddebug_add_module() dynamic_debug.c: - add externs to the linker symbols. ddebug_add_module(): - It currently builds a debug_table, and *will* find and attach classes. dynamic_debug_init(): - add class fields to the _ddebug_info cursor var: di. Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-16-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman

dyndbg: add DECLARE_DYNDBG_CLASSMAP macro

2022-09-07T15:04:49+00:00

Using DECLARE_DYNDBG_CLASSMAP, modules can declare up to 31 classnames. By doing so, they authorize dyndbg to manipulate class'd prdbgs (ie: __pr_debug_cls, and soon drm_*dbg), ala:: :#> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control The macro declares and initializes a static struct ddebug_class_map:: - maps approved class-names to class_ids used in module, by array order. forex: DRM_UT_* - class-name vals allow validation of "class FOO" queries using macro is opt-in - enum class_map_type - determines interface, behavior Each module has its own class-type and class_id space, and only known class-names will be authorized for a manipulation. Only DRM modules should know and respont to this: :#> echo class DRM_UT_CORE +p > control # across all modules pr_debugs (with default class_id) are still controllable as before. DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, classes...) is:: _var: name of the static struct var. user passes to module_param_cb() if they want a sysfs node. _maptype: this is hard-coded to DD_CLASS_TYPE_DISJOINT_BITS for now. _base: usually 0, it allows splitting 31 classes into subranges, so that multiple classes / sysfs-nodes can share the module's class-id space. classes: list of class_name strings, these are mapped to class-ids starting at _base. This class-names list must have a corresponding ENUM, with SYMBOLS that match the literals, and 1st enum val = _base. enum class_map_type has 4 values, on 2 factors:: - classes are disjoint/independent vs relative/xcontrol interface doesn't enforce the LEVELS relationship, so you could confusingly have V3 enabled, but V1 disabled. OTOH, the control iface already allows infinite tweaking of the underlying callsites; sysfs node readback can only tell the user what they previously wrote. 2. All dyndbg >control reduces to a query/command, includes +/-, which is at-root a kernel patching operation with +/- semantics. And the _NAMES handling exposes it to the user, making it API-adjacent. And its not just >control where +/- gets used (which is settled), the new place is with sysfs-nodes exposing _*_NAMES classes, and here its subtly different. _DISJOINT_NAMES: is simple, independent _LEVEL_NAMES: masks-on bits 0 .. N-1, N..max off # turn on L3,L2,L1 others off echo +L3 > /sys/module/test_dynamic_debug/parameters/p_level_names # turn on L2,L1 others off echo -L3 > /sys/module/test_dynamic_debug/parameters/p_level_names IOW, the - changes the threshold-on bitpos by 1. Alternatively, we could treat the +/- as half-duplex, where -L3 turns off L>2 (and ignores L1), and +L2 would turn on L<=2 (and ignore others). Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-15-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman

dyndbg: add __pr_debug_cls for testing

2022-09-07T15:04:49+00:00

For selftest purposes, add __pr_debug_cls(class, fmt, ...) I didn't think we'd need to define this, since DRM effectively has it already in drm_dbg, drm_devdbg. But test_dynamic_debug needs it in order to demonstrate all the moving parts. Note the __ prefix; its not intended for general use, at least until a need emerges. ISTM the drm.debug model (macro wrappers inserting enum const 1st arg) is the baseline approach. That said, nouveau might want it for easy use in its debug macros. TBD. NB: it does require a builtin-constant class, __pr_debug_cls(i++, ...) is disallowed by compiler. Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-14-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman

dyndbg: add class_id to pr_debug callsites

2022-09-07T15:04:48+00:00

DRM issues ~10 exclusive categories of debug messages; to represent this directly in dyndbg, add a new 6-bit field: struct _ddebug.class_id. This gives us 64 classes, which should be more than enough. #> echo 0x012345678 > /sys/module/drm/parameters/debug All existing callsites are initialized with _DPRINTK_CLASS_DFLT, which is 2^6-1. This reserves 0-62 for use in new categorized/class'd pr_debugs, which fits perfectly with natural enums (ints: 0..N). Thats done by extending the init macro: DEFINE_DYNAMIC_DEBUG_METADATA() with _CLS(cls, ...) suffix, and redefing old name using extended name. Then extend the factory macro callchain with _cls() versions to provide the callsite.class_id, with old-names passing _DPRINTK_CLASS_DFLT. This sets us up to create class'd prdebug callsites (class'd callsites are those with .class_id != _DPRINTK_CLASS_DFLT). No behavior change. cc: Rasmus Villemoes Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-13-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman

dyndbg: gather __dyndbg[] state into struct _ddebug_info

2022-09-07T15:04:48+00:00

This new struct composes the linker provided (vector,len) section, and provides a place to add other __dyndbg[] state-data later: descs - the vector of descriptors in __dyndbg section. num_descs - length of the data/section. Use it, in several different ways, as follows: In lib/dynamic_debug.c: ddebug_add_module(): Alter params-list, replacing 2 args (array,index) with a struct _ddebug_info * containing them both, with room for expansion. This helps future-proof the function prototype against the looming addition of class-map info into the dyndbg-state, by providing a place to add more member fields later. NB: later add static struct _ddebug_info builtins_state declaration, not needed yet. ddebug_add_module() is called in 2 contexts: In dynamic_debug_init(), declare, init a struct _ddebug_info di auto-var to use as a cursor. Then iterate over the prdbg blocks of the builtin modules, and update the di cursor before calling _add_module for each. Its called from kernel/module/main.c:load_info() for each loaded module: In internal.h, alter struct load_info, replacing the dyndbg array,len fields with an embedded _ddebug_info containing them both; and populate its members in find_module_sections(). The 2 calling contexts differ in that _init deals with contiguous subranges of __dyndbgs[] section, packed together, while loadable modules are added one at a time. So rename ddebug_add_module() into outer/__inner fns, call __inner from _init, and provide the offset into the builtin __dyndbgs[] where the module's prdbgs reside. The cursor provides start, len of the subrange for each. The offset will be used later to pack the results of builtin __dyndbg_sites[] de-duplication, and is 0 and unneeded for loadable modules, Note: kernel/module/main.c includes for struct _ddeubg_info. This might be prone to include loops, since its also included by printk.h. Nothing has broken in robot-land on this. cc: Luis Chamberlain Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-12-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman

dyndbg: drop EXPORTed dynamic_debug_exec_queries

2022-09-07T14:58:23+00:00

This exported fn is unused, and will not be needed. Lets dump it. The export was added to let drm control pr_debugs, as part of using them to avoid drm_debug_enabled overheads. But its better to just implement the drm.debug bitmap interface, then its available for everyone. Fixes: a2d375eda771 ("dyndbg: refine export, rename to dynamic_debug_exec_queries()") Fixes: 4c0d77828d4f ("dyndbg: export ddebug_exec_queries") Acked-by: Jason Baron Acked-by: Daniel Vetter Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-10-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman