From: Jim Cromie <[email protected]>
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
class_names.length <= 32
(class_names.length + _base) < 63
dd-map-type is known value
These compile-time checks will prevent several simple misuses, issuing
obvious errors if violated.
several bad examples are ifdef DDD_MACRO_ARGCHECK qualified, into
test_dynamic_debug_submod.ko, and will fail compilation if added to
cflags.
Signed-off-by: Jim Cromie <[email protected]>
---
v5: additional test: classes.length <= 32
old-v13
reword 2 failing tests (active only when -DDD_MACRO_ARGCHECK is
passed to cc) to better identify what error is being tested against
-v12
check map-type at compile-time
make base+len(classnames) check more explicit
dyndbg-test: add more tests of compile-time CHECKs
add 3 tests of static-asserts added to 2 macros:
DYNAMIC_DEBUG_CLASSMAP_{DEFINE,USE_}
_DEFINE():
1- validates maptype,
2- validate classmap.length + base-offset < 63
_USE_():
3- validate user-offset < 63
As before, these tests fail when activated:
make KCPPFLAGS="-DDD_MACRO_ARGCHECK" lib/test_dynamic_debug_submod.o
NOTE: _USE_() cannot test classmap.length, since its a property of
the referent, not the macro itself.
dyndbg-test: verify DYNAMIC_DEBUG_CLASSMAP_USE_() compile-time CHECK
Add another failing use-case, this time to verify that _USE properly
rejects an offset > 62. This is an incomplete test; the proper test
is: classes.length + base + offset < 63, but the macro cannot test
classes.length at compile-time.
Signed-off-by: Jim Cromie <[email protected]>
---
include/linux/dynamic_debug.h | 16 +++++++++++++++-
lib/test_dynamic_debug.c | 20 +++++++++++++++++---
2 files changed, 32 insertions(+), 4 deletions(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 17fc3a29d97b..471b9891bd83 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -197,6 +197,19 @@ struct ddebug_class_param {
* __pr_debug_cls(22, "no such class"); compiles but is not reachable
*/
+#define __DYNAMIC_DEBUG_CLASSMAP_CHECK(_clnames, _base, _mapty)
\
+ static_assert(((_base) >= 0 && (_base) < _DPRINTK_CLASS_DFLT), \
+ "_base must be in 0..62"); \
+ static_assert(__DDEBUG_ARRAY_SIZE(_clnames) > 0,
\
+ "classnames array size must be > 0"); \
+ static_assert(__DDEBUG_ARRAY_SIZE(_clnames) <= 32,
\
+ "classnames array size must be <= 32"); \
+ static_assert((__DDEBUG_ARRAY_SIZE(_clnames) + (_base)) <
_DPRINTK_CLASS_DFLT, \
+ "_base + classnames.length must be <= 62"); \
+ static_assert(((_mapty) >= DD_CLASS_TYPE_DISJOINT_BITS) && \
+ ((_mapty) <= DD_CLASS_TYPE_LEVEL_NUM), \
+ "unknown class_map_type")
+
/**
* DYNAMIC_DEBUG_CLASSMAP_DEFINE - define debug classes used by a module.
* @_var: name of the classmap, exported for other modules coordinated use.
@@ -210,6 +223,7 @@ struct ddebug_class_param {
*/
#define DYNAMIC_DEBUG_CLASSMAP_DEFINE(_var, _mapty, _base, ...)
\
static const char *_var##_classnames[] = { __VA_ARGS__ }; \
+ __DYNAMIC_DEBUG_CLASSMAP_CHECK(_var##_classnames, (_base), (_mapty)); \
extern struct ddebug_class_map _var; \
struct ddebug_class_map __aligned(8) __used \
__section("__dyndbg_class_maps") _var = { \
@@ -217,7 +231,7 @@ struct ddebug_class_param {
.mod_name = DDEBUG_MODNAME, \
.base = (_base), \
.map_type = (_mapty), \
- .length = ARRAY_SIZE(_var##_classnames), \
+ .length = __DDEBUG_ARRAY_SIZE(_var##_classnames), \
.class_names = _var##_classnames, \
}; \
EXPORT_SYMBOL(_var)
diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index 3a69cc3cae6d..01ce07001d4c 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -148,12 +148,26 @@ DYNAMIC_DEBUG_CLASSMAP_USE_(map_level_num, 7);
enum cat_level_offset { Vu1 = V1 + 7, Vu2, Vu3, Vu4, Vu5, Vu6, Vu7 };
-#endif
-
+#if defined(DD_MACRO_ARGCHECK)
/*
- * now add the sysfs-params
+ * Exersize compile-time arg-checks in DYNAMIC_DEBUG_CLASSMAP_DEFINE.
+ * These will break compilation.
*/
+DYNAMIC_DEBUG_CLASSMAP_DEFINE(fail_base_neg, 0, -1, "NEGATIVE_BASE_ARG");
+DYNAMIC_DEBUG_CLASSMAP_DEFINE(fail_base_big, 0, 100, "TOOBIG_BASE_ARG");
+DYNAMIC_DEBUG_CLASSMAP_DEFINE(fail_str_type, 0, 0, 1 /* not a string */);
+DYNAMIC_DEBUG_CLASSMAP_DEFINE(fail_emptyclass, 0, 0 /* ,empty */);
+DYNAMIC_DEBUG_CLASSMAP_DEFINE(fail_maptype, 3, 10, "no such type");
+DYNAMIC_DEBUG_CLASSMAP_DEFINE(fail_base_len, 0, 60,
+ "base", "plus", "classes", "length", "too-big");
+DYNAMIC_DEBUG_CLASSMAP_USE_(fail_offset_big, 100);
+#endif /* DD_MACRO_ARGCHECK */
+
+#endif /* TEST_DYNAMIC_DEBUG_SUBMOD */
+/*
+ * now add the sysfs-params to both sub/super-mods
+ */
DYNAMIC_DEBUG_CLASSMAP_PARAM(disjoint_bits, p);
DYNAMIC_DEBUG_CLASSMAP_PARAM(level_num, p);
--
2.55.0
