Le 15/04/2025 à 21:54, jim.cromie@gmail.com a écrit :
> On Tue, Apr 15, 2025 at 4:04 AM Louis Chauvet <louis.chauvet@bootlin.com> wrote:
>>
>>
>>
>> Le 02/04/2025 à 19:41, Jim Cromie a écrit :
>>> Add __DYNAMIC_DEBUG_CLASSMAP_CHECK to implement the following
>>> arg-checks at compile-time:
>>>
>>> 0 <= _base < 63
>>> class_names is not empty
>>> class_names[0] is a string
>>
>> I don't see where this is checked, did I miss something?
>
> kinda/sorta ? theres no explicit check for "string".
> BUT
> this would fail, cuz 1 doesnt fit into a char* arr[0]
You are totally right, I was looking for a static_assert, but the
compiler do some checks too, sorry!
>>> +DYNDBG_CLASSMAP_DEFINE(fail_str_type, 0, 0, 1 /* not a string */);
>
> Im perhaps over-simplifying the description
>
>>
>>> (class_names.length + _base) < 63
>>>
>>> These compile-time checks will prevent several misuses; 4 such
>>> examples are added to test_dynamic_debug_submod.ko, and will fail
>>> compilation if -DDD_MACRO_ARGCHECK is added to cflags. This wouldn't
>>> be a useful CONFIG_ item, since it breaks the build.
>>>
>>> Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
>>> ---
>>> v3- $macro_name =~ s/DYNDBG/DYNAMIC_DEBUG/
>>>
>>> prev-
>>> - split static-asserts to __DYNDBG_CLASSMAP_CHECK
>>> - move __DYNDBG_CLASSMAP_CHECK above kdoc for DYNDBG_CLASSMAP_DEFINE
>>> silences kernel-doc warnings
>>> ---
>>> include/linux/dynamic_debug.h | 9 +++++++++
>>> lib/test_dynamic_debug.c | 11 +++++++++++
>>> 2 files changed, 20 insertions(+)
>>>
>>> diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
>>> index 9af825c84e70..4941ef2adb46 100644
>>> --- a/include/linux/dynamic_debug.h
>>> +++ b/include/linux/dynamic_debug.h
>>> @@ -99,6 +99,14 @@ struct _ddebug_class_map {
>>> enum ddebug_class_map_type map_type;
>>> };
>>>
>>> +#define __DYNAMIC_DEBUG_CLASSMAP_CHECK(_clnames, _base) \
>>> + static_assert(((_base) >= 0 && (_base) < _DPRINTK_CLASS_DFLT), \
>>> + "_base must be in 0..62"); \
>>> + static_assert(ARRAY_SIZE(_clnames) > 0, \
>>> + "classnames array size must be > 0"); \
>>> + static_assert((ARRAY_SIZE(_clnames) + (_base)) < _DPRINTK_CLASS_DFLT, \
>>> + "_base + classnames.length exceeds range")
>>> +
>>> /**
>>> * DYNAMIC_DEBUG_CLASSMAP_DEFINE - define debug classes used by a module.
>>> * @_var: name of the classmap, exported for other modules coordinated use.
>>> @@ -112,6 +120,7 @@ struct _ddebug_class_map {
>>> */
>>> #define DYNAMIC_DEBUG_CLASSMAP_DEFINE(_var, _mapty, _base, ...) \
>>> static const char *_var##_classnames[] = { __VA_ARGS__ }; \
>>
>> Or maybe it was already enforced by this, but in this case the commit
>> message contains too much checks.
>>
>>> + __DYNAMIC_DEBUG_CLASSMAP_CHECK(_var##_classnames, (_base)); \
>>> extern struct _ddebug_class_map _var; \
>>> struct _ddebug_class_map __aligned(8) __used \
>>> __section("__dyndbg_class_maps") _var = { \
>>> diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
>>> index e42916b08fd4..9f9e3fddd7e6 100644
>>> --- a/lib/test_dynamic_debug.c
>>> +++ b/lib/test_dynamic_debug.c
>>> @@ -146,8 +146,19 @@ DYNDBG_CLASSMAP_DEFINE(classid_range_conflict, 0, D2_CORE + 1, "D3_CORE");
>>> DYNAMIC_DEBUG_CLASSMAP_USE(map_disjoint_bits);
>>> DYNAMIC_DEBUG_CLASSMAP_USE(map_level_num);
>>>
>>> +#if defined(DD_MACRO_ARGCHECK)
>>> +/*
>>> + * Exersize compile-time arg-checks in DYNDBG_CLASSMAP_DEFINE.
>>> + * These will break compilation.
>>> + */
>>> +DYNDBG_CLASSMAP_DEFINE(fail_base_neg, 0, -1, "NEGATIVE_BASE_ARG");
>>> +DYNDBG_CLASSMAP_DEFINE(fail_base_big, 0, 100, "TOOBIG_BASE_ARG");
>>> +DYNDBG_CLASSMAP_DEFINE(fail_str_type, 0, 0, 1 /* not a string */);
>>> +DYNDBG_CLASSMAP_DEFINE(fail_emptyclass, 0, 0 /* ,empty */);
>>> #endif
>>>
>>> +#endif /* TEST_DYNAMIC_DEBUG_SUBMOD */
>>> +
>>> /* stand-in for all pr_debug etc */
>>> #define prdbg(SYM) __pr_debug_cls(SYM, #SYM " msg\n")
>>>
>>
>> --
>> Louis Chauvet, Bootlin
>> Embedded Linux and Kernel engineering
>> https://bootlin.com
>>
>>
--
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com