@@ -56,6 +56,62 @@ struct _ddebug {
#endif
} __attribute__((aligned(8)));
+enum class_map_type {
+ DD_CLASS_TYPE_DISJOINT_BITS,
+ /**
+ * DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, one per bit.
+ * expecting hex input. Built for drm.debug, basis for other types.
+ */
+ DD_CLASS_TYPE_LEVEL_NUM,
+ /**
+ * DD_CLASS_TYPE_LEVEL_NUM: input is numeric level, 0-N.
+ * N turns on just bits N-1 .. 0, so N=0 turns all bits off.
+ */
+ DD_CLASS_TYPE_DISJOINT_NAMES,
+ /**
+ * DD_CLASS_TYPE_DISJOINT_NAMES: input is a CSV of [+-]CLASS_NAMES,
+ * classes are independent, like _DISJOINT_BITS. Model user
+ * would be /sys/module/drm/parameters/debug_categories.
+ */
+ DD_CLASS_TYPE_LEVEL_NAMES,
+ /**
+ * DD_CLASS_TYPE_LEVEL_NAMES: input is a CSV of [+-]CLASS_NAMES,
+ * intended for names like: INFO,DEBUG,TRACE, with a module prefix
+ * avoid EMERG,ALERT,CRIT,ERR,WARNING: they're not debug
+ */
+};
+
+struct ddebug_class_map {
+ struct list_head link;
+ struct module *mod;
+ const char *mod_name; /* needed for builtins */
+ const char **class_names;
+ const int length;
+ const int base; /* index of 1st .class_id, allows split/shared space */
+ enum class_map_type map_type;
+};
+
+/**
+ * DECLARE_DYNDBG_CLASSMAP - declare classnames known by a module
+ * @_var: a struct ddebug_class_map, passed to module_param_cb
+ * @_type: enum class_map_type, chooses bits/verbose, numeric/symbolic
+ * @_base: offset of 1st class-name. splits .class_id space
+ * @classes: class-names used to control class'd prdbgs
+ */
+#define DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, ...) \
+ static const char *_var##_classnames[] = { __VA_ARGS__ }; \
+ static struct ddebug_class_map __aligned(8) __used \
+ __section("__dyndbg_classes") _var = { \
+ .mod = THIS_MODULE, \
+ .mod_name = KBUILD_MODNAME, \
+ .base = _base, \
+ .map_type = _maptype, \
+ .length = NUM_TYPE_ARGS(char*, __VA_ARGS__), \
+ .class_names = _var##_classnames, \
+ }
+#define NUM_TYPE_ARGS(eltype, ...) \
+ (sizeof((eltype[]){__VA_ARGS__}) / sizeof(eltype))
+
/* encapsulate linker provided built-in (or module) dyndbg data */
struct _ddebug_info {
struct _ddebug *descs;
With 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) :#> 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_id space, and only known class-names will be authorized for a manipulation. Only DRM stuff should know 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/x<y/verbosity. disjoint is basis, verbosity by overlay. - input NUMBERS vs [+-]CLASS_NAMES uints, ideally hex. vs +DRM_UT_CORE,-DRM_UT_KMS DD_CLASS_TYPE_DISJOINT_BITS: classes are separate, one per bit. expecting hex input. built for drm.debug, basis for other types. DD_CLASS_TYPE_DISJOINT_NAMES: input is a CSV of [+-]CLASS_NAMES, classes are independent, like DISJOINT DD_CLASS_TYPE_LEVEL_NUM: input is numeric level, 0-N. 0 implies silence. use printk to break that. relative levels applied on bitmaps. DD_CLASS_TYPE_LEVEL_NAMES: input is a CSV of [+-]CLASS_NAMES, names like: ERR,WARNING,NOTICE,INFO,DEBUG avoiding EMERG,ALERT,CRIT,ERR - no point. NOTES: The macro places the initialized struct ddebug_class_map into the __dyndbg_classes section. That draws a 'orphan' warning which we handle in next commit. The struct attributes are necessary: __aligned(8) stopped null-ptr derefs (why?), __used is needed by drm drivers, which declare class-maps, but don't also declare a sysfs-param, and thus dont ref the classmap; __used insures that the linkage is made, then the class-map is found at load-time. While its possible to handle both NAMES and NUMBERS in the same sys-interface, there is ambiguity to avoid, by disallowing them together. Later, if ambiguities are resolved, 2 new enums can permit both inputs, on verbose & independent types separately, and authors can select the interface they like. The plan is to implement LEVELS in the callbacks, outside of ddebug_exec_query(), which for simplicity will treat the CLASSES in the map as disjoint. The callbacks can see map-type, and apply ++/-- loops (or bitops) to force the relative meanings across the class-bitmap. RFC: That leaves 2 issues: 1. doing LEVELs in callbacks means that the native >control 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 <jim.cromie@gmail.com> --- . revised DD_CLASS_TYPE_{DISJOINT,LEVEL}_* names . reorder-enum by necessity - _NAMES feature is extra. --- include/linux/dynamic_debug.h | 56 +++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+)