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Date: Tue, 21 May 2024 13:46:47 +0200
From: Łukasz Bartosik <ukaszb@...omium.org>
To: Jim Cromie <jim.cromie@...il.com>
Cc: jbaron@...mai.com, gregkh@...uxfoundation.org,
linux-kernel@...r.kernel.org, linux@...musvillemoes.dk, joe@...ches.com,
mcgrof@...nel.org, daniel.vetter@...ll.ch, tvrtko.ursulin@...ux.intel.com,
jani.nikula@...el.com, ville.syrjala@...ux.intel.com, seanpaul@...omium.org,
robdclark@...il.com, groeck@...gle.com, yanivt@...gle.com, bleung@...gle.com
Subject: Re: [PATCH v8-RESEND 15/33] dyndbg-API: fix DECLARE_DYNDBG_CLASSMAP
On Thu, May 16, 2024 at 7:44 PM Jim Cromie <jim.cromie@...il.com> wrote:
>
> DECLARE_DYNDBG_CLASSMAP() has a design error; its usage fails a basic
> K&R rule: "define once, refer many times".
>
> It is used across DRM core & drivers, each use re-defines the classmap
> understood by that module; and all must match for the modules to
> respond together when DRM.debug categories are enabled. This is
> brittle; a maintenance foot-gun.
>
> Worse, it causes the CONFIG_DRM_USE_DYNAMIC_DEBUG=Y regression; 1st
> drm.ko loads, and dyndbg initializes its DRM.debug callsites, then a
> drm-driver loads, but too late - it missed the DRM.debug enablement.
>
> So replace it with 2 macros:
> DYNDBG_CLASSMAP_DEFINE - invoked once from core - drm.ko
> DYNDBG_CLASSMAP_USE - from all drm drivers and helpers.
>
> DYNDBG_CLASSMAP_DEFINE: it reuses a renamed DECLARE_DYNDBG_CLASSMAP to
> construct the struct classmap variable, but it drops the static
> qualifier, and exports it instead.
>
> DYNDBG_CLASSMAP_USE: then refers to the exported var by name:
> * used from drivers, helper-mods
> * lets us drop the repetitive "classname" args
> * fixes 2nd-defn problem
> * creates a ddebug_class_user record in new __dyndbg_class_users section
> this allows ddebug_add_module(etal) to handle them per-module.
>
> DECLARE_DYNDBG_CLASSMAP is preserved temporarily, to decouple DRM
> adaptation work and avoid compile-errs before its done. IOW, DRM
> gets fixed when they commit the adopt-new-api patches.
>
> The DEFINE,USE distinction, and the separate usage record, allows
> dyndbg to initialize the drivers & helpers DRM.debug callsites
> separately after each is modprobed.
>
> Basically, the classmap init-scan repeated for classmap-users.
>
> To review, dyndbg's existing __dyndbg_classes[] section does:
>
> . catalogs the classmaps defined by a module (or builtin modules)
> . authorizes dyndbg to >control those class'd prdbgs for the module.
> . DYNDBG_CLASSMAP_DEFINE creates classmaps in this section.
>
> This patch adds __dyndbg_class_users[] section:
>
> . catalogs uses/references to the classmap definitions.
> . authorizes dyndbg to >control those class'd prdbgs in ref'g module.
> . DYNDBG_CLASSMAP_USE() creates classmap-user records in this new section.
>
> Now ddebug_add_module(etal) can handle classmap-uses similar to (and
> after) classmaps; when a dependent module is loaded, its parent's
> kernel params are scanned to find if a param is wired to dyndbg's
> param-ops, whose classmap ref is the one being looked for.
>
> To support this, theres a few data/header changes:
>
> new struct ddebug_class_user
> contains: user-module-name, &classmap-defn
> it records drm-driver's use of a classmap in the section, allowing lookup
>
> struct ddebug_info gets 2 new fields to contain the new section:
> class_users, num_class_users.
> set by dynamic_debug_init() for builtins.
> or by kernel/module/main:load_info() for loadable modules.
>
> vmlinux.lds.h: new BOUNDED_SECTION for __dyndbg_class_users
>
> dynamic_debug.c has 2 changes in ddebug_add_module(), ddebug_change():
>
> ddebug_add_module() already calls ddebug_attach_module_classes()
> to handle classmaps DEFINEd by a module, now it also calls
> ddebug_attach_user_module_classes() to handle USEd classmaps. To
> avoid this work when possible, 1st scan the module's descriptors and
> count the number of class'd pr_debugs.
>
> ddebug_attach_user_module_classes() scans the module's class_users
> section, follows the refs to the parent's classmap, and calls
> ddebug_apply_params() on each. It also avoids work by checking the
> module's class-ct.
>
> ddebug_apply_params(new fn):
>
> It scans module's/builtin kernel-params, calls ddebug_match_apply_kparam
> for each to find the params/sysfs-nodes which may be wired to a classmap.
>
> ddebug_match_apply_kparam(new fn):
>
> 1st, it tests the kernel-param.ops is dyndbg's; this guarantees that
> the attached arg is a struct ddebug_class_param, which has a ref to
> the param's state, and to the classmap defining the param's handling.
>
> 2nd, it requires that the classmap ref'd by the kparam is the one
> we're called for; modules can use many separate classmaps (as
> test_dynamic_debug does).
>
> Then apply the "parent" kparam's setting to the dependent module,
> using ddebug_apply_class_bitmap().
>
> ddebug_change(and callees) also gets adjustments:
>
> ddebug_find_valid_class(): This does a search over the module's
> classmaps, looking for the class FOO echo'd to >control. So now it
> searches over __dyndbg_class_users[] after __dyndbg_classes[].
>
> ddebug_class_name(): return class-names for defined AND used classes.
>
> test_dynamic_debug.c, test_dynamic_debug_submod.c:
>
> This demonstrates the 2 types of classmaps & sysfs-params, following
> the 4-part recipe:
>
> 1. define an enum for the classmap: DRM.debug has DRM_UT_{CORE,KMS,...}
> multiple classes must share 0-62 classid space.
> 2. DYNDBG_CLASSMAP_DEFINE(.. DRM_UT_{CORE,KMS,...})
> 3. DYNDBG_CLASSMAP_PARAM* (classmap)
> 4. DYNDBG_CLASSMAP_USE()
> by _submod only, skipping 2,3
>
> Move all the enum declarations together, to better explain how they
> share the 0..62 class-id space available to a module (non-overlapping
> subranges).
>
> reorg macros 2,3 by name. This gives a tabular format, making it easy
> to see the pattern of repetition, and the points of change.
>
> And extend the test to replicate the 2-module (parent & dependent)
> scenario which caused the CONFIG_DRM_USE_DYNAMIC_DEBUG=y regression
> seen in drm & drivers.
>
> The _submod.c is a 2-line file: #define _SUBMOD, #include parent.
>
> This gives identical complements of prdbgs in parent & _submod, and
> thus identical print behavior when all of: >control, >params, and
> parent->_submod propagation are working correctly.
>
> It also puts all the parent/_submod declarations together in the same
> source, with the new ifdef _SUBMOD block invoking DYNDBG_CLASSMAP_USE
> for the 2 test-interfaces. I think this is clearer.
>
> These 2 modules are both tristate, allowing 3 super/sub combos: Y/Y,
> Y/M, M/M (not N/N). Y/Y testing exposed a missing __align(8) in the
> _METADATA macro, which M/M didn't see because the module-loader memory
> placement constrains it instead.
>
> DEBUG details:
>
> ``#define DEBUG`` in src enables all pr_debugs after it, including any
> class'd pr_debugs; its not necessarily all-or-nothing, unless you do
> the define in a header. Also, the only way to disable a class'd
> pr_debug is via the classmap-kparam or using "class foo" in control
> queries, to address the classes by name.
>
> NB: this patch ignores a checkpatch do-while warning; which is wrong
> for declarative macros like these:
>
> arch/powerpc/platforms/cell/spu_base.c
> 48:static DEFINE_SPINLOCK(spu_lock);
> 62:static DEFINE_SPINLOCK(spu_full_list_lock);
> 63:static DEFINE_MUTEX(spu_full_list_mutex);
>
> Fixes: aad0214f3026 ("dyndbg: add DECLARE_DYNDBG_CLASSMAP macro")
> Signed-off-by: Jim Cromie <jim.cromie@...il.com>
> ---
> v8 - split drm parts to separate commits.
> preserve DECLARE_DYNDBG_CLASSMAP to decouple DRM, no flag day.
> fixup block comment
>
> v7 - previous submission-blocking bug:
>
> missing __align(8) in DYNAMIC_DEBUG_DECLARE_METADATA on
> ddebug_class_user caused corrupt records, but only for builtin
> modules; module loader code probably pinned allocations to the right
> alignment naturally, hiding the bug for typical builds.
>
> v6- get rid of WARN_ON_ONCE
> v?- fix _var expanded 2x in macro
> ---
> MAINTAINERS | 2 +-
> include/asm-generic/vmlinux.lds.h | 1 +
> include/linux/dynamic_debug.h | 62 ++++++++--
> kernel/module/main.c | 3 +
> lib/Kconfig.debug | 24 +++-
> lib/Makefile | 3 +
> lib/dynamic_debug.c | 183 ++++++++++++++++++++++++++----
> lib/test_dynamic_debug.c | 111 ++++++++++++------
> lib/test_dynamic_debug_submod.c | 10 ++
> 9 files changed, 331 insertions(+), 68 deletions(-)
> create mode 100644 lib/test_dynamic_debug_submod.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 28e20975c26f..c9ed48109ff5 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7526,7 +7526,7 @@ M: Jim Cromie <jim.cromie@...il.com>
> S: Maintained
> F: include/linux/dynamic_debug.h
> F: lib/dynamic_debug.c
> -F: lib/test_dynamic_debug.c
> +F: lib/test_dynamic_debug*.c
>
> DYNAMIC INTERRUPT MODERATION
> M: Tal Gilboa <talgi@...dia.com>
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index f7749d0f2562..f1d8e64b244c 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -365,6 +365,7 @@
> /* implement dynamic printk debug */ \
> . = ALIGN(8); \
> BOUNDED_SECTION_BY(__dyndbg_classes, ___dyndbg_classes) \
> + BOUNDED_SECTION_BY(__dyndbg_class_users, ___dyndbg_class_users) \
> BOUNDED_SECTION_BY(__dyndbg, ___dyndbg) \
> LIKELY_PROFILE() \
> BRANCH_PROFILE() \
> diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
> index dd304e231f08..2c6944c0d6cd 100644
> --- a/include/linux/dynamic_debug.h
> +++ b/include/linux/dynamic_debug.h
> @@ -72,8 +72,8 @@ enum ddebug_class_map_type {
> };
>
> struct ddebug_class_map {
> - struct module *mod;
> - const char *mod_name; /* needed for builtins */
> + const struct module *mod; /* NULL for builtins */
> + const char *mod_name;
> const char **class_names;
> const int length;
> const int base; /* index of 1st .class_id, allows split/shared space */
> @@ -81,11 +81,34 @@ struct ddebug_class_map {
> };
>
> /**
> - * 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
> + * DYNDBG_CLASSMAP_DEFINE - define a set of debug-classes used by a module.
> + * @_var: name of the classmap, exported for other modules coordinated use.
> + * @_type: enum ddebug_class_map_type, chooses bits/verbose, numeric/names.
> + * @_base: offset of 1st class-name, used to share 0..62 classid space
> + * @classes: vals are stringified enum-vals, like DRM_UT_*
> + *
Why does DYNDBG_CLASSMAP_DEFINE take "stringified" enum name-vals ?
> + * Defines and exports a struct ddebug_class_map whose @classes are
> + * used to validate a "class FOO .." >control command on the module
> + */
> +#define __DYNDBG_CLASSMAP_DEFINE(_var, _maptype, _base, ...) \
> + const char *_var##_classnames[] = { __VA_ARGS__ }; \
> + struct ddebug_class_map __aligned(8) __used \
> + __section("__dyndbg_classes") _var = { \
> + .mod = THIS_MODULE, \
> + .mod_name = KBUILD_MODNAME, \
> + .base = _base, \
> + .map_type = _maptype, \
> + .length = ARRAY_SIZE(_var##_classnames), \
> + .class_names = _var##_classnames, \
> + }
> +#define DYNDBG_CLASSMAP_DEFINE(_var, ...) \
> + __DYNDBG_CLASSMAP_DEFINE(_var, __VA_ARGS__); \
> + EXPORT_SYMBOL(_var)
> +
> +/*
> + * XXX: keep this until DRM adapts to use the DEFINE/USE api, it
> + * differs from __DYNDBG_CLASSMAP_DEFINE only in the static on the
> + * struct decl.
> */
> #define DECLARE_DYNDBG_CLASSMAP(_var, _maptype, _base, ...) \
> static const char *_var##_classnames[] = { __VA_ARGS__ }; \
> @@ -99,12 +122,37 @@ struct ddebug_class_map {
> .class_names = _var##_classnames, \
> }
>
> +struct ddebug_class_user {
> + char *user_mod_name;
> + struct ddebug_class_map *map;
> +};
> +
> +/**
> + * DYNDBG_CLASSMAP_USE - refer to a classmap, DEFINEd elsewhere.
> + * @_var: name of the exported classmap var
> + *
> + * This registers a module's use of another module's classmap defn, so
> + * dyndbg can authorize "class DRM_CORE ..." >control commands upon
> + * this module.
> + */
> +#define DYNDBG_CLASSMAP_USE(_var) \
> + DYNDBG_CLASSMAP_USE_(_var, __UNIQUE_ID(ddebug_class_user))
> +#define DYNDBG_CLASSMAP_USE_(_var, _uname) \
> + extern struct ddebug_class_map _var; \
> + static struct ddebug_class_user __aligned(8) __used \
> + __section("__dyndbg_class_users") _uname = { \
> + .user_mod_name = KBUILD_MODNAME, \
> + .map = &(_var), \
> + }
> +
> /* encapsulate linker provided built-in (or module) dyndbg data */
> struct _ddebug_info {
> struct _ddebug *descs;
> struct ddebug_class_map *classes;
> + struct ddebug_class_user *class_users;
> unsigned int num_descs;
> unsigned int num_classes;
> + unsigned int num_class_users;
> };
>
> struct ddebug_class_param {
> diff --git a/kernel/module/main.c b/kernel/module/main.c
> index e1e8a7a9d6c1..9f7ce0f0e6e5 100644
> --- a/kernel/module/main.c
> +++ b/kernel/module/main.c
> @@ -2217,6 +2217,9 @@ static int find_module_sections(struct module *mod, struct load_info *info)
> mod->dyndbg_info.classes = section_objs(info, "__dyndbg_classes",
> sizeof(*mod->dyndbg_info.classes),
> &mod->dyndbg_info.num_classes);
> + mod->dyndbg_info.class_users = section_objs(info, "__dyndbg_class_users",
> + sizeof(*mod->dyndbg_info.class_users),
> + &mod->dyndbg_info.num_class_users);
> #endif
>
> return 0;
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 291185f54ee4..7acca866bb22 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -2797,12 +2797,26 @@ config TEST_STATIC_KEYS
> If unsure, say N.
>
> config TEST_DYNAMIC_DEBUG
> - tristate "Test DYNAMIC_DEBUG"
> - depends on DYNAMIC_DEBUG
> + tristate "Build test-dynamic-debug module"
> + depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
> help
> - This module registers a tracer callback to count enabled
> - pr_debugs in a 'do_debugging' function, then alters their
> - enablements, calls the function, and compares counts.
> + This module exersizes/demonstrates dyndbg's classmap API, by
Typo exersizes -> exercises
> + creating 2 classes: a DISJOINT classmap (supporting DRM.debug)
> + and a LEVELS/VERBOSE classmap (like verbose2 > verbose1).
> +
> + If unsure, say N.
> +
> +config TEST_DYNAMIC_DEBUG_SUBMOD
> + tristate "Build test-dynamic-debug submodule"
> + default m
> + depends on DYNAMIC_DEBUG || DYNAMIC_DEBUG_CORE
> + depends on TEST_DYNAMIC_DEBUG
> + help
> + This sub-module uses a classmap defined and exported by the
> + parent module, recapitulating drm & driver's shared use of
> + drm.debug to control enabled debug-categories.
> + It is tristate, independent of parent, to allow testing all
> + proper combinations of parent=y/m submod=y/m.
>
> If unsure, say N.
>
> diff --git a/lib/Makefile b/lib/Makefile
> index ffc6b2341b45..d3e6a48f202b 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -82,6 +82,7 @@ obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o
> obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
> obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
> obj-$(CONFIG_TEST_DYNAMIC_DEBUG) += test_dynamic_debug.o
> +obj-$(CONFIG_TEST_DYNAMIC_DEBUG_SUBMOD) += test_dynamic_debug_submod.o
> obj-$(CONFIG_TEST_PRINTF) += test_printf.o
> obj-$(CONFIG_TEST_SCANF) += test_scanf.o
>
> @@ -240,6 +241,8 @@ obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
> obj-$(CONFIG_DYNAMIC_DEBUG_CORE) += dynamic_debug.o
> #ensure exported functions have prototypes
> CFLAGS_dynamic_debug.o := -DDYNAMIC_DEBUG_MODULE
> +CFLAGS_test_dynamic_debug.o := -DDYNAMIC_DEBUG_MODULE
> +CFLAGS_test_dynamic_debug_submod.o := -DDYNAMIC_DEBUG_MODULE
>
> obj-$(CONFIG_SYMBOLIC_ERRNAME) += errname.o
>
> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> index d5701207febc..f0a274a3cc9e 100644
> --- a/lib/dynamic_debug.c
> +++ b/lib/dynamic_debug.c
> @@ -43,13 +43,16 @@ extern struct _ddebug __start___dyndbg[];
> extern struct _ddebug __stop___dyndbg[];
> extern struct ddebug_class_map __start___dyndbg_classes[];
> extern struct ddebug_class_map __stop___dyndbg_classes[];
> +extern struct ddebug_class_user __start___dyndbg_class_users[];
> +extern struct ddebug_class_user __stop___dyndbg_class_users[];
>
> struct ddebug_table {
> struct list_head link;
> const char *mod_name;
> struct _ddebug *ddebugs;
> struct ddebug_class_map *classes;
> - unsigned int num_ddebugs, num_classes;
> + struct ddebug_class_user *class_users;
> + unsigned int num_ddebugs, num_classes, num_class_users;
> };
>
> struct ddebug_query {
> @@ -148,21 +151,39 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
> query->first_lineno, query->last_lineno, query->class_string);
> }
>
> +#define vpr_dt_info(dt_p, msg_p, ...) ({ \
> + struct ddebug_table const *_dt = dt_p; \
> + v2pr_info(msg_p " module:%s nd:%d nc:%d nu:%d\n", ##__VA_ARGS__, \
> + _dt->mod_name, _dt->num_ddebugs, _dt->num_classes, \
> + _dt->num_class_users); \
> + })
> +
> #define __outvar /* filled by callee */
> static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt,
> const char *class_string,
> __outvar int *class_id)
> {
> struct ddebug_class_map *map;
> + struct ddebug_class_user *cli;
> int i, idx;
>
> - for (map = dt->classes, i = 0; i < dt->num_classes; i++, map++) {
> + for (i = 0, map = dt->classes; i < dt->num_classes; i++, map++) {
> idx = match_string(map->class_names, map->length, class_string);
> if (idx >= 0) {
> *class_id = idx + map->base;
> + vpr_dt_info(dt, "good-class: %s.%s ", map->mod_name, class_string);
> return map;
> }
> }
> + for (i = 0, cli = dt->class_users; i < dt->num_class_users; i++, cli++) {
> + idx = match_string(cli->map->class_names, cli->map->length, class_string);
> + if (idx >= 0) {
> + *class_id = idx + cli->map->base;
> + vpr_dt_info(dt, "class-ref: %s.%s ",
> + cli->user_mod_name, class_string);
> + return cli->map;
> + }
> + }
> *class_id = -ENOENT;
> return NULL;
> }
> @@ -559,7 +580,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
>
> /* handle multiple queries in query string, continue on error, return
> last error or number of matching callsites. Module name is either
> - in param (for boot arg) or perhaps in query string.
> + in the modname arg (for boot args) or perhaps in query string.
> */
> static int ddebug_exec_queries(char *query, const char *modname)
> {
> @@ -688,12 +709,12 @@ static int param_set_dyndbg_module_classes(const char *instr,
> }
>
> /**
> - * param_set_dyndbg_classes - class FOO >control
> + * param_set_dyndbg_classes - set all classes in a classmap
> * @instr: string echo>d to sysfs, input depends on map_type
> - * @kp: kp->arg has state: bits/lvl, map, map_type
> + * @kp: kp->arg has state: bits/lvl, classmap, map_type
> *
> - * Enable/disable prdbgs by their class, as given in the arguments to
> - * DECLARE_DYNDBG_CLASSMAP. For LEVEL map-types, enforce relative
> + * For all classes in the classmap, enable/disable them per the input
> + * (depending on map_type). For LEVEL map-types, enforce relative
> * levels by bitpos.
> *
> * Returns: 0 or <0 if error.
> @@ -1038,12 +1059,17 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
> static const char *ddebug_class_name(struct ddebug_table *dt, struct _ddebug *dp)
> {
> struct ddebug_class_map *map = dt->classes;
> + struct ddebug_class_user *cli = dt->class_users;
> int i;
>
> for (i = 0; i < dt->num_classes; i++, map++)
> if (class_in_range(dp->class_id, map))
> return map->class_names[dp->class_id - map->base];
>
> + for (i = 0; i < dt->num_class_users; i++, cli++)
> + if (class_in_range(dp->class_id, cli->map))
> + return cli->map->class_names[dp->class_id - cli->map->base];
> +
> return NULL;
> }
>
> @@ -1124,31 +1150,133 @@ static const struct proc_ops proc_fops = {
> .proc_write = ddebug_proc_write
> };
>
> +static const char * const ddebug_classmap_typenames[] = {
> + "DISJOINT_BITS", "LEVEL_NUM"
> +};
> +
> +#define vpr_cm_info(cm_p, msg_p, ...) ({ \
> + struct ddebug_class_map const *_cm = cm_p; \
> + v2pr_info(msg_p " module:%s base:%d len:%d type:%s\n", ##__VA_ARGS__, \
> + _cm->mod_name, _cm->base, _cm->length, \
> + ddebug_classmap_typenames[_cm->map_type]); \
> + })
> +
> +static void ddebug_sync_classbits(const struct ddebug_class_param *dcp, const char *modname)
> +{
> + /* clamp initial bitvec, mask off hi-bits */
> + if (*dcp->bits & ~CLASSMAP_BITMASK(dcp->map->length)) {
> + *dcp->bits &= CLASSMAP_BITMASK(dcp->map->length);
> + v2pr_info("preset classbits: %lx\n", *dcp->bits);
> + }
> + /* force class'd prdbgs (in USEr module) to match (DEFINEr module) class-param */
> + ddebug_apply_class_bitmap(dcp, dcp->bits, ~0, modname);
> + ddebug_apply_class_bitmap(dcp, dcp->bits, 0, modname);
> +}
> +
> +static void ddebug_match_apply_kparam(const struct kernel_param *kp,
> + const struct ddebug_class_map *map,
> + const char *modnm)
> +{
> + struct ddebug_class_param *dcp;
> +
> + if (kp->ops != ¶m_ops_dyndbg_classes)
> + return;
> +
> + dcp = (struct ddebug_class_param *)kp->arg;
> +
> + if (map == dcp->map) {
> + v2pr_info("found kp:%s =0x%lx", kp->name, *dcp->bits);
> + vpr_cm_info(map, "mapped to:");
> + ddebug_sync_classbits(dcp, modnm);
> + }
> +}
> +
> +static void ddebug_apply_params(const struct ddebug_class_map *cm, const char *modnm)
> +{
> + const struct kernel_param *kp;
> +#if IS_ENABLED(CONFIG_MODULES)
Instead of the above maybe use "if (IS_ENABLED(CONFIG_MODULES)) {" ?
This will allow to get rid of #if and #endif which make code less readable.
> + int i;
> +
> + if (cm->mod) {
> + vpr_cm_info(cm, "loaded class:");
> + for (i = 0, kp = cm->mod->kp; i < cm->mod->num_kp; i++, kp++)
> + ddebug_match_apply_kparam(kp, cm, modnm);
> + }
> +#endif
> + if (!cm->mod) {
> + vpr_cm_info(cm, "builtin class:");
> + for (kp = __start___param; kp < __stop___param; kp++)
> + ddebug_match_apply_kparam(kp, cm, modnm);
> + }
> +}
> +
> +/*
> + * Find this module's classmaps in a sub/whole-range of the builtin/
> + * modular classmap vector/section. Save the start and length of the
> + * subrange at its edges.
> + */
> static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug_info *di)
> {
> struct ddebug_class_map *cm;
> int i, nc = 0;
>
> - /*
> - * Find this module's classmaps in a subrange/wholerange of
> - * the builtin/modular classmap vector/section. Save the start
> - * and length of the subrange at its edges.
> - */
> - for (cm = di->classes, i = 0; i < di->num_classes; i++, cm++) {
> + for (i = 0, cm = di->classes; i < di->num_classes; i++, cm++) {
>
> if (!strcmp(cm->mod_name, dt->mod_name)) {
> - if (!nc) {
> - v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n",
> - i, cm->mod_name, cm->base, cm->length, cm->map_type);
> + vpr_cm_info(cm, "classes[%d]:", i);
> + if (!nc++)
> dt->classes = cm;
> - }
> - nc++;
> }
> }
> - if (nc) {
> - dt->num_classes = nc;
> - vpr_info("module:%s attached %d classes\n", dt->mod_name, nc);
> + if (!nc)
> + return;
> +
> + vpr_info("module:%s attached %d classes\n", dt->mod_name, nc);
> + dt->num_classes = nc;
> +
> + for (i = 0, cm = dt->classes; i < dt->num_classes; i++, cm++)
> + ddebug_apply_params(cm, cm->mod_name);
> +}
> +
> +/*
> + * propagates class-params thru their classmaps to class-users. this
> + * means a query against the dt/module, which means it must be on the
> + * list to be seen by ddebug_change.
> + */
> +static void ddebug_attach_user_module_classes(struct ddebug_table *dt,
> + const struct _ddebug_info *di)
> +{
> + struct ddebug_class_user *cli;
> + int i, nc = 0;
> +
> + /*
> + * For builtins: scan the array, find start/length of this
> + * module's refs, save to dt. For loadables, this is the
> + * whole array.
> + */
> + for (i = 0, cli = di->class_users; i < di->num_class_users; i++, cli++) {
> +
> + if (WARN_ON_ONCE(!cli || !cli->map || !cli->user_mod_name))
> + continue;
> +
> + if (!strcmp(cli->user_mod_name, dt->mod_name)) {
> +
> + vpr_cm_info(cli->map, "class_ref[%d] %s -> %s", i,
> + cli->user_mod_name, cli->map->mod_name);
> + if (!nc++)
> + dt->class_users = cli;
> + }
> }
> + if (!nc)
> + return;
> +
> + dt->num_class_users = nc;
> +
> + /* now iterate dt */
> + for (i = 0, cli = dt->class_users; i < dt->num_class_users; i++, cli++)
> + ddebug_apply_params(cli->map, cli->user_mod_name);
> +
> + vpr_dt_info(dt, "attach-client-module: ");
> }
>
> /*
> @@ -1158,6 +1286,8 @@ static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug
> static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
> {
> struct ddebug_table *dt;
> + struct _ddebug *iter;
> + int i, class_ct = 0;
>
> if (!di->num_descs)
> return 0;
> @@ -1181,13 +1311,20 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname)
>
> INIT_LIST_HEAD(&dt->link);
>
> - if (di->classes && di->num_classes)
> + for (i = 0, iter = di->descs; i < di->num_descs; i++, iter++)
> + if (iter->class_id != _DPRINTK_CLASS_DFLT)
> + class_ct++;
> +
> + if (class_ct && di->num_classes)
> ddebug_attach_module_classes(dt, di);
>
> mutex_lock(&ddebug_lock);
> list_add_tail(&dt->link, &ddebug_tables);
> mutex_unlock(&ddebug_lock);
>
> + if (class_ct && di->num_class_users)
> + ddebug_attach_user_module_classes(dt, di);
> +
> vpr_info("%3u debug prints in module %s\n", di->num_descs, modname);
> return 0;
> }
> @@ -1337,8 +1474,10 @@ static int __init dynamic_debug_init(void)
> struct _ddebug_info di = {
> .descs = __start___dyndbg,
> .classes = __start___dyndbg_classes,
> + .class_users = __start___dyndbg_class_users,
> .num_descs = __stop___dyndbg - __start___dyndbg,
> .num_classes = __stop___dyndbg_classes - __start___dyndbg_classes,
> + .num_class_users = __stop___dyndbg_class_users - __start___dyndbg_class_users,
> };
>
> #ifdef CONFIG_MODULES
> diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
> index 9e950a911b6c..ff9b879286d5 100644
> --- a/lib/test_dynamic_debug.c
> +++ b/lib/test_dynamic_debug.c
> @@ -6,11 +6,15 @@
> * Jim Cromie <jim.cromie@...il.com>
> */
>
> -#define pr_fmt(fmt) "test_dd: " fmt
> +#if defined(TEST_DYNAMIC_DEBUG_SUBMOD)
> + #define pr_fmt(fmt) "test_dd_submod: " fmt
> +#else
> + #define pr_fmt(fmt) "test_dd: " fmt
> +#endif
>
> #include <linux/module.h>
>
> -/* run tests by reading or writing sysfs node: do_prints */
> +/* re-gen output by reading or writing sysfs node: do_prints */
>
> static void do_prints(void); /* device under test */
> static int param_set_do_prints(const char *instr, const struct kernel_param *kp)
> @@ -29,24 +33,39 @@ static const struct kernel_param_ops param_ops_do_prints = {
> };
> module_param_cb(do_prints, ¶m_ops_do_prints, NULL, 0600);
>
> -/*
> - * Using the CLASSMAP api:
> - * - classmaps must have corresponding enum
> - * - enum symbols must match/correlate with class-name strings in the map.
> - * - base must equal enum's 1st value
> - * - multiple maps must set their base to share the 0-30 class_id space !!
> - * (build-bug-on tips welcome)
> - * Additionally, here:
> - * - tie together sysname, mapname, bitsname, flagsname
> - */
> -#define DD_SYS_WRAP(_model, _flags) \
> - static unsigned long bits_##_model; \
> - static struct ddebug_class_param _flags##_model = { \
> +#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, ¶m_ops_dyndbg_classes, &_flags##_model, 0600)
> + module_param_cb(_flags##_##_model, ¶m_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.
> + *
> + * Each is 3 part: client-enum decl, _DEFINE, _PARAM.
> + * Declare them in blocks to show patterns of use (repetitions and
> + * changes) within each.
> + *
> + * 1st, dyndbg expects a client-provided enum-type as source of
> + * category/classid truth. DRM has DRM_UT_<CORE,DRIVER,KMS,etc>.
> + *
> + * Modules with multiple CLASSMAPS must have enums with distinct
> + * value-ranges, arranged below with explicit enum_sym = X inits.
> + *
> + * Declare all 4 enums now, for different types
> + */
>
> /* numeric input, independent bits */
> enum cat_disjoint_bits {
> @@ -60,26 +79,51 @@ enum cat_disjoint_bits {
> D2_LEASE,
> D2_DP,
> D2_DRMRES };
> -DECLARE_DYNDBG_CLASSMAP(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS, 0,
> - "D2_CORE",
> - "D2_DRIVER",
> - "D2_KMS",
> - "D2_PRIME",
> - "D2_ATOMIC",
> - "D2_VBL",
> - "D2_STATE",
> - "D2_LEASE",
> - "D2_DP",
> - "D2_DRMRES");
> -DD_SYS_WRAP(disjoint_bits, p);
> -DD_SYS_WRAP(disjoint_bits, T);
>
> /* numeric verbosity, V2 > V1 related */
> enum cat_level_num { V0 = 14, V1, V2, V3, V4, V5, V6, V7 };
> -DECLARE_DYNDBG_CLASSMAP(map_level_num, DD_CLASS_TYPE_LEVEL_NUM, 14,
> - "V0", "V1", "V2", "V3", "V4", "V5", "V6", "V7");
> -DD_SYS_WRAP(level_num, p);
> -DD_SYS_WRAP(level_num, T);
> +
> +/* recapitulate DRM's parent(drm.ko) <-- _submod(drivers,helpers) */
> +#if !defined(TEST_DYNAMIC_DEBUG_SUBMOD)
> +/*
> + * In single user, or parent / coordinator (drm.ko) modules, define
> + * classmaps on the client enums above, and then declares the PARAMS
> + * ref'g the classmaps. Each is exported.
> + */
> +DYNDBG_CLASSMAP_DEFINE(map_disjoint_bits, DD_CLASS_TYPE_DISJOINT_BITS,
> + D2_CORE,
> + "D2_CORE",
> + "D2_DRIVER",
> + "D2_KMS",
> + "D2_PRIME",
> + "D2_ATOMIC",
> + "D2_VBL",
> + "D2_STATE",
> + "D2_LEASE",
> + "D2_DP",
> + "D2_DRMRES");
> +
> +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
> + */
> +
> +DYNDBG_CLASSMAP_PARAM(disjoint_bits, p);
> +DYNDBG_CLASSMAP_PARAM(level_num, p);
> +
> +#else /* TEST_DYNAMIC_DEBUG_SUBMOD */
> +
> +/*
> + * in submod/drm-drivers, use the classmaps defined in top/parent
> + * module above.
> + */
> +
> +DYNDBG_CLASSMAP_USE(map_disjoint_bits);
> +DYNDBG_CLASSMAP_USE(map_level_num);
> +
> +#endif
>
> /* stand-in for all pr_debug etc */
> #define prdbg(SYM) __pr_debug_cls(SYM, #SYM " msg\n")
> @@ -115,6 +159,7 @@ static void do_levels(void)
>
> static void do_prints(void)
> {
> + pr_debug("do_prints:\n");
> do_cats();
> do_levels();
> }
> diff --git a/lib/test_dynamic_debug_submod.c b/lib/test_dynamic_debug_submod.c
> new file mode 100644
> index 000000000000..9a893402ce1a
> --- /dev/null
> +++ b/lib/test_dynamic_debug_submod.c
> @@ -0,0 +1,10 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Kernel module for testing dynamic_debug
> + *
> + * Authors:
> + * Jim Cromie <jim.cromie@...il.com>
> + */
> +
> +#define TEST_DYNAMIC_DEBUG_SUBMOD
> +#include "test_dynamic_debug.c"
> --
> 2.45.0
>
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