[PATCH v4 15/21] dyndbg-API: promote DYNDBG_CLASSMAP_PARAM to API

From: Jim Cromie
Date: Thu Jul 13 2023 - 12:39:01 EST

move macro from test-dynamic-debug.c into header, and refine it.

Distinguish the 2 use cases of DYNDBG_CLASSMAP_PARAM*

1.DYNDBG_CLASSMAP_PARAM_REF
for DRM, to pass in extern __drm_debug by name.
dyndbg keeps bits in it, so drm can still use it as before/remaining.

2.DYNDBG_CLASSMAP_PARAM
new user (test_dynamic_debug) doesnt need to share state,
decls,inits a static long unsigned int to store the bitvec.

__DYNDBG_CLASSMAP_PARAM
bottom layer - allocate,init a ddebug-class-param, module-param-cb.

1. doesnt initialize bits properly.
macro seems to lose type of previously decl'd extern,
then whines about type mistmatch
punt now - following commit trys to fix it, draws warning.

2. init seems to work
maybe masked by sync-bits
not validated

Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx>
---
drivers/gpu/drm/drm_print.c | 8 ++-----
include/drm/drm_print.h | 6 ++++--
include/linux/dynamic_debug.h | 39 +++++++++++++++++++++++++++++++++--
lib/test_dynamic_debug.c | 22 +++-----------------
4 files changed, 46 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
index dabcfa0dd279..8f4b609353a5 100644
--- a/drivers/gpu/drm/drm_print.c
+++ b/drivers/gpu/drm/drm_print.c
@@ -69,12 +69,8 @@ DRM_CLASSMAP_DEFINE(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS,
"DRM_UT_DP",
"DRM_UT_DRMRES");

-static struct ddebug_class_param drm_debug_bitmap = {
- .bits = &__drm_debug,
- .flags = "p",
- .map = &drm_debug_classes,
-};
-module_param_cb(debug, &param_ops_dyndbg_classes, &drm_debug_bitmap, 0600);
+DRM_CLASSMAP_PARAM_REF(debug, __drm_debug, drm_debug_classes, p);
+
#endif

void __drm_puts_coredump(struct drm_printer *p, const char *str)
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
index 706afc97c79c..94d4f5500030 100644
--- a/include/drm/drm_print.h
+++ b/include/drm/drm_print.h
@@ -322,11 +322,13 @@ enum drm_debug_category {
};

#ifdef CONFIG_DRM_USE_DYNAMIC_DEBUG
-#define DRM_CLASSMAP_DEFINE(...) DYNDBG_CLASSMAP_DEFINE(__VA_ARGS__)
-#define DRM_CLASSMAP_USE(name) DYNDBG_CLASSMAP_USE(name)
+#define DRM_CLASSMAP_DEFINE(...) DYNDBG_CLASSMAP_DEFINE(__VA_ARGS__)
+#define DRM_CLASSMAP_USE(name) DYNDBG_CLASSMAP_USE(name)
+#define DRM_CLASSMAP_PARAM_REF(...) DYNDBG_CLASSMAP_PARAM_REF(__VA_ARGS__)
#else
#define DRM_CLASSMAP_DEFINE(...)
#define DRM_CLASSMAP_USE(name)
+#define DRM_CLASSMAP_PARAM_REF(...)
#endif

static inline bool drm_debug_enabled_raw(enum drm_debug_category category)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 2604fda3abe3..95a6b3882b76 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -90,7 +90,7 @@ struct ddebug_class_map {
* module, and to validate inputs to DD_CLASS_TYPE_*_NAMES typed params.
*/
#define DYNDBG_CLASSMAP_DEFINE(_var, _maptype, _base, ...) \
- const char *_var##_classnames[] = { __VA_ARGS__ }; \
+ static const char *_var##_classnames[] = { __VA_ARGS__ }; \
struct ddebug_class_map __aligned(8) __used \
__section("__dyndbg_classes") _var = { \
.mod = THIS_MODULE, \
@@ -118,7 +118,7 @@ struct ddebug_class_user {
DYNDBG_CLASSMAP_USE_(_var, __UNIQUE_ID(ddebug_class_user))
#define DYNDBG_CLASSMAP_USE_(_var, _uname) \
extern struct ddebug_class_map _var; \
- struct ddebug_class_user __used \
+ static struct ddebug_class_user __used \
__section("__dyndbg_class_users") _uname = { \
.user_mod_name = KBUILD_MODNAME, \
.map = &_var, \
@@ -143,6 +143,41 @@ struct ddebug_class_param {
const struct ddebug_class_map *map;
};

+/**
+ * DYNDBG_CLASSMAP_PARAM - wrap a dyndbg-classmap with a controlling sys-param
+ * @_name sysfs node name
+ * @_var name of the struct classmap var defining the controlled classes
+ * @_flags flags to be toggled, typically just 'p'
+ *
+ * Creates a sysfs-param to control the classes defined by the
+ * classmap. Keeps bits in a private/static
+ */
+#define DYNDBG_CLASSMAP_PARAM(_name, _var, _flags) \
+ static unsigned long _name##_bvec; \
+ __DYNDBG_CLASSMAP_PARAM(_name, _name##_bvec, _var, _flags)
+
+/**
+ * DYNDBG_CLASSMAP_PARAM_REF - wrap a dyndbg-classmap with a controlling sys-param
+ * @_name sysfs node name
+ * @_bits name of the module's unsigned long bit-vector, ex: __drm_debug
+ * @_var name of the struct classmap var defining the controlled classes
+ * @_flags flags to be toggled, typically just 'p'
+ *
+ * Creates a sysfs-param to control the classmap, keeping bitvec in user @_bits.
+ * This lets drm use __drm_debug elsewhere too.
+ */
+#define DYNDBG_CLASSMAP_PARAM_REF(_name, _bits, _var, _flags) \
+ __DYNDBG_CLASSMAP_PARAM(_name, _bits, _var, _flags)
+
+#define __DYNDBG_CLASSMAP_PARAM(_name, _bits, _var, _flags) \
+ static struct ddebug_class_param _name##_##_flags = { \
+ .bits = &_bits, \
+ .flags = #_flags, \
+ .map = &_var, \
+ }; \
+ module_param_cb(_name, &param_ops_dyndbg_classes, \
+ &_name##_##_flags, 0600)
+
/*
* pr_debug() and friends are globally enabled or modules have selectively
* enabled them.
diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index 23967071b60f..df41963d9faf 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -35,22 +35,6 @@ module_param_cb(do_prints, &param_ops_do_prints, NULL, 0600);

#define CLASSMAP_BITMASK(width, base) (((1UL << (width)) - 1) << base)

-/* sysfs param wrapper, proto-API */
-#define DYNDBG_CLASSMAP_PARAM_(_model, _flags, _init) \
- static unsigned long bits_##_model = _init; \
- static struct ddebug_class_param _flags##_##_model = { \
- .bits = &bits_##_model, \
- .flags = #_flags, \
- .map = &map_##_model, \
- }; \
- module_param_cb(_flags##_##_model, &param_ops_dyndbg_classes, \
- &_flags##_##_model, 0600)
-#ifdef DEBUG
-#define DYNDBG_CLASSMAP_PARAM(_model, _flags) DYNDBG_CLASSMAP_PARAM_(_model, _flags, ~0)
-#else
-#define DYNDBG_CLASSMAP_PARAM(_model, _flags) DYNDBG_CLASSMAP_PARAM_(_model, _flags, 0)
-#endif
-
/*
* Demonstrate/test all 4 class-typed classmaps with a sys-param.
*
@@ -113,11 +97,11 @@ DYNDBG_CLASSMAP_DEFINE(map_level_num, DD_CLASS_TYPE_LEVEL_NUM,
V0, "V0", "V1", "V2", "V3", "V4", "V5", "V6", "V7");

/*
- * now add the sysfs-params
+ * now add the sysfs-params: name, classmap, flags-toggled
*/

-DYNDBG_CLASSMAP_PARAM(disjoint_bits, p);
-DYNDBG_CLASSMAP_PARAM(level_num, p);
+DYNDBG_CLASSMAP_PARAM(p_disjoint_bits, map_disjoint_bits, p);
+DYNDBG_CLASSMAP_PARAM(p_level_num, map_level_num, p);

#else /* TEST_DYNAMIC_DEBUG_SUBMOD */

--
2.41.0