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?
(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.cro...@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
