From patchwork Fri Oct 13 22:48:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jim Cromie X-Patchwork-Id: 13421846 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 17FBDCDB485 for ; Fri, 13 Oct 2023 22:49:36 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9376E10E68C; Fri, 13 Oct 2023 22:48:59 +0000 (UTC) Received: from mail-il1-x12f.google.com (mail-il1-x12f.google.com [IPv6:2607:f8b0:4864:20::12f]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8F4F510E67B; Fri, 13 Oct 2023 22:48:52 +0000 (UTC) Received: by mail-il1-x12f.google.com with SMTP id e9e14a558f8ab-3512efed950so9927265ab.2; Fri, 13 Oct 2023 15:48:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1697237332; x=1697842132; darn=lists.freedesktop.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Xt5GYS9mXBsgXWCKjkvZOfiO8j43yK6Z0bFknFJi+ls=; b=QpNd1UDX2oHF5jBE43mEFmPBNnYQxAuITgVTwd1BlP+ZCDAgSnyyMC9vl7nHqTXW0u JnIQegLpDslkuFozQsAZNV6TwdrGbnVgBu0kknL3q8dwH2cAYfJHe2EdYy5KaGX+cryY nrrQNoV3Rx6UEXouL7qjlabqcq9SPjeII1JzdL7INCHXMuEzR+iSSxFV0y/pRn5AnGtY hNgTuG+LEOfqD6bO9JZWrfRvJ8Cs7vMLxKIzfUb7OT/eB/f4fnMk3GeV2CbWzUCs8VEi c1Pof2YFptDqOoVod7UxKfNfL+wLCTq7h31Pem+E0jfCquKbmITPZ3VYVf2ifL9E5rhA nWFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697237332; x=1697842132; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Xt5GYS9mXBsgXWCKjkvZOfiO8j43yK6Z0bFknFJi+ls=; b=mmMoSUw6ZsOYaafIEBPWK4hhM9uOOr4/6Mn9n0qA2kOwXByQWL1xQDtCMHJmI6UjRI 6bSYLJ3aIGk0EMW8ZYVYMyv1mc2aNa4WLR5OZHC8m7DlNnJ/KKCnPKr+/7/ySxM7v9RQ jDvqlFbP9k8+FN7LuAYRydJxj2xUyvZQ+irBm8ns4CNDJvPNhQgv3EAiEyfb5aMvUCmz Js0GrY2v0Hno9zXMyGcqdf82+fv6unrywTB+KDc4CBFCwtNZn+ej2/1M2OTadnle2F1P nuxRd3MRLrfylX49OVSKQwjggSixG8lJJ0JnQ6ipLNHzZIToCBAO6J+64I9J1cVJk8gy IqgQ== X-Gm-Message-State: AOJu0Yy0WhbnPvcH4FKhRBzTXbhyBY2dsU58Jh1eO8PW8pvwFZxqfxQk 5HlVZmmO3NR3pXXsIEvTkU4= X-Google-Smtp-Source: AGHT+IGqQ1iwV3rhmpHdu75VZNFfcZihQtqNSLpY33tZ2e3fX8O3LgvYIt+m1LEyZYRdn0zTAq8rIA== X-Received: by 2002:a92:cdac:0:b0:357:4a69:60d8 with SMTP id g12-20020a92cdac000000b003574a6960d8mr10470030ild.4.1697237331792; Fri, 13 Oct 2023 15:48:51 -0700 (PDT) Received: from frodo.. (c-73-78-62-130.hsd1.co.comcast.net. [73.78.62.130]) by smtp.googlemail.com with ESMTPSA id t10-20020a92dc0a000000b003512c3e8809sm1683071iln.71.2023.10.13.15.48.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Oct 2023 15:48:51 -0700 (PDT) From: Jim Cromie To: linux-kernel@vger.kernel.org, jbaron@akamai.com, gregkh@linuxfoundation.org, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Date: Fri, 13 Oct 2023 16:48:10 -0600 Message-ID: <20231013224818.3456409-19-jim.cromie@gmail.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231013224818.3456409-1-jim.cromie@gmail.com> References: <20231013224818.3456409-1-jim.cromie@gmail.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v7b 18/25] dyndbg-doc: add classmap info to howto X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: lb@semihalf.com, groeck@google.com, linux-doc@vger.kernel.org, jani.nikula@intel.com, daniel.vetter@ffwll.ch, linux@rasmusvillemoes.dk, Jim Cromie , mcgrof@kernel.org, seanpaul@chromium.org, joe@perches.com, bleung@google.com, yanivt@google.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Add some basic info on classmap usage and api cc: linux-doc@vger.kernel.org Signed-off-by: Jim Cromie --- v5- adjustments per Randy Dunlap, me v7b- checkpatch fixes --- .../admin-guide/dynamic-debug-howto.rst | 60 ++++++++++++++++++- 1 file changed, 59 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst index 0b3d39c610d9..028c2cb5b4c5 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 +374,62 @@ 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 are have prdbgs with those +class_ids, and they authorize dyndbg to accept "class FOO" for the +module defining that classname. + +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 - refers to a DEFINEd classmap, exposing the set +of defined classes to manipulation as a group. This interface +enforces the relatedness of classes of DD_CLASS_TYPE_LEVEL_NUM typed +classmaps; all classes are independent in the >control parser itself. + +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. + +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 pr_debug callsites can be toggled into agreement with the +param.