From: Jim Cromie <jim.cromie@gmail.com>
To: jbaron@akamai.com, gregkh@linuxfoundation.org,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
amd-gfx@lists.freedesktop.org,
intel-gvt-dev@lists.freedesktop.org,
intel-gfx@lists.freedesktop.org
Cc: ukaszb@chromium.org, linux-doc@vger.kernel.org,
daniel.vetter@ffwll.ch, tvrtko.ursulin@linux.intel.com,
jani.nikula@intel.com, ville.syrjala@linux.intel.com,
seanpaul@chromium.org, robdclark@gmail.com, groeck@google.com,
yanivt@google.com, bleung@google.com,
Jim Cromie <jim.cromie@gmail.com>
Subject: [PATCH v8 20/35] dyndbg-doc: add classmap info to howto
Date: Mon, 29 Apr 2024 13:39:06 -0600 [thread overview]
Message-ID: <20240429193921.66648-1-jim.cromie@gmail.com> (raw)
Describe the 3 API macros providing dynamic_debug's classmaps
DYNDBG_CLASSMAP_DEFINE - create, exports a module's classmap
DYNDBG_CLASSMAP_USE - refer to exported map
DYNDBG_CLASSMAP_PARAM - bind control param to the classmap
DYNDBG_CLASSMAP_PARAM_REF + use module's storage - __drm_debug
cc: linux-doc@vger.kernel.org
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
v5 adjustments per Randy Dunlap
v7 checkpatch fixes
v8 more
---
.../admin-guide/dynamic-debug-howto.rst | 63 ++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst
index 6a8ce5a34382..742eb4230c6e 100644
--- a/Documentation/admin-guide/dynamic-debug-howto.rst
+++ b/Documentation/admin-guide/dynamic-debug-howto.rst
@@ -225,7 +225,6 @@ the ``p`` flag has meaning, other flags are ignored.
Note the regexp ``^[-+=][fslmpt_]+$`` matches a flags specification.
To clear all flags at once, use ``=_`` or ``-fslmpt``.
-
Debug messages during Boot Process
==================================
@@ -375,3 +374,65 @@ just a shortcut for ``print_hex_dump(KERN_DEBUG)``.
For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is
its ``prefix_str`` argument, if it is constant string; or ``hexdump``
in case ``prefix_str`` is built dynamically.
+
+Dynamic Debug classmaps
+=======================
+
+Dyndbg allows selection/grouping of *prdbg* callsites using structural
+info: module, file, function, line. Classmaps allow authors to add
+their own domain-oriented groupings using class-names. Classmaps are
+exported, so they referencable from other modules.
+
+ # enable classes individually
+ :#> ddcmd class DRM_UT_CORE +p
+ :#> ddcmd class DRM_UT_KMS +p
+ # or more selectively
+ :#> ddcmd class DRM_UT_CORE module drm +p
+
+The "class FOO" syntax protects class'd prdbgs from generic overwrite::
+
+ # IOW this doesn't wipe any DRM.debug settings
+ :#> ddcmd -p
+
+To support the DRM.debug parameter, DYNDBG_CLASSMAP_PARAM* updates all
+classes in a classmap, mapping param-bits 0..N onto the classes:
+DRM_UT_<*> for the DRM use-case.
+
+Dynamic Debug Classmap API
+==========================
+
+DYNDBG_CLASSMAP_DEFINE - modules use this to create classmaps, naming
+each of the classes (stringified enum-symbols: "DRM_UT_<*>"), and
+type, and mapping the class-names to consecutive _class_ids.
+
+By doing so, modules tell dyndbg that they have prdbgs with those
+class_ids, and they authorize dyndbg to accept "class FOO" for the
+module defining the classmap, and its contained classnames.
+
+DYNDBG_CLASSMAP_USE - drm drivers invoke this to ref the CLASSMAP that
+drm DEFINEs. This shares the classmap definition, and authorizes
+dyndbg to apply changes to the user module's class'd pr_debugs. It
+also tells dyndbg how to initialize the user's prdbgs at modprobe,
+based upon the current setting of the parent's controlling param.
+
+There are 2 types of classmaps:
+
+ DD_CLASS_TYPE_DISJOINT_BITS: classes are independent, like DRM.debug
+ DD_CLASS_TYPE_LEVEL_NUM: classes are relative, ordered (V3 > V2)
+
+DYNDBG_CLASSMAP_PARAM - modelled after module_param_cb, it refers to a
+DEFINEd classmap, and associates it to the param's data-store. This
+state is then applied to DEFINEr and USEr modules when they're modprobed.
+
+This interface also enforces the DD_CLASS_TYPE_LEVEL_NUM relation
+amongst the contained classnames; all classes are independent in the
+control parser itself.
+
+Modules or module-groups (drm & drivers) can define multiple
+classmaps, as long as they share the limited 0..62 per-module-group
+_class_id range, without overlap.
+
+``#define DEBUG`` will enable all pr_debugs in scope, including any
+class'd ones. This won't be reflected in the PARAM readback value,
+but the class'd pr_debug callsites can be forced off by toggling the
+classmap-kparam all-on then all-off.
--
2.44.0
next reply other threads:[~2024-04-29 19:39 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-29 19:39 Jim Cromie [this message]
2024-04-29 19:39 ` [PATCH v8 21/35] dyndbg: treat comma as a token separator Jim Cromie
2024-04-29 19:39 ` [PATCH v8 22/35] selftests-dyndbg: add comma_terminator_tests Jim Cromie
2024-04-29 19:39 ` [PATCH v8 23/35] dyndbg: split multi-query strings with % Jim Cromie
2024-04-29 19:39 ` [PATCH v8 24/35] selftests-dyndbg: test_percent_splitting multi-cmds on module classes Jim Cromie
2024-04-29 19:39 ` [PATCH v8 25/35] docs/dyndbg: explain new delimiters: comma, percent Jim Cromie
2024-04-29 19:39 ` [PATCH v8 26/35] selftests-dyndbg: add test_mod_submod Jim Cromie
2024-04-29 19:39 ` [PATCH v8 27/35] selftests-dyndbg: test dyndbg-to-tracefs Jim Cromie
2024-04-29 19:39 ` [PATCH v8 28/35] dyndbg-doc: explain flags parse 1st Jim Cromie
2024-04-29 19:39 ` [PATCH v8 29/35] dyndbg: add __counted_by annotations Jim Cromie
2024-04-30 18:49 ` jim.cromie
2024-04-29 19:39 ` [PATCH v8 30/35] drm+drivers: adapt to use DYNDBG_CLASSMAP_{DEFINE, USE} Jim Cromie
2024-04-29 19:39 ` [PATCH v8 31/35] drm-dyndbg: adapt to use DYNDBG_CLASSMAP_PARAM Jim Cromie
2024-04-29 19:39 ` [PATCH v8 32/35] drm: use correct ccflags-y spelling Jim Cromie
2024-04-29 19:39 ` [PATCH v8 33/35] drm-drivers: DRM_CLASSMAP_USE in 2nd batch of drivers, helpers Jim Cromie
2024-04-29 19:39 ` [PATCH v8 34/35] drm: restore CONFIG_DRM_USE_DYNAMIC_DEBUG un-BROKEN Jim Cromie
2024-04-29 19:39 ` [PATCH v8 35/35] drm-print: workaround compiler meh Jim Cromie
-- strict thread matches above, loose matches on Subject: below --
2024-04-29 19:31 [PATCH v8 00/35] fix CONFIG_DRM_USE_DYNAMIC_DEBUG=y regression Jim Cromie
2024-04-29 19:31 ` [PATCH v8 20/35] dyndbg-doc: add classmap info to howto Jim Cromie
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