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[67.165.245.5]) by smtp.googlemail.com with ESMTPSA id e9e14a558f8ab-3d5d5af8369sm33439725ab.71.2025.04.02.10.42.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Apr 2025 10:42:40 -0700 (PDT) From: Jim Cromie To: jbaron@akamai.com, gregkh@linuxfoundation.org, ukaszb@chromium.org, louis.chauvet@bootlin.com, linux-kernel@vger.kernel.org Cc: dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, daniel.vetter@ffwll.ch, tvrtko.ursulin@linux.intel.com, jani.nikula@intel.com, ville.syrjala@linux.intel.com, Jim Cromie Subject: [PATCH v3 27/54] dyndbg: drop "protection" of class'd pr_debugs from legacy queries Date: Wed, 2 Apr 2025 11:41:29 -0600 Message-ID: <20250402174156.1246171-28-jim.cromie@gmail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250402174156.1246171-1-jim.cromie@gmail.com> References: <20250402174156.1246171-1-jim.cromie@gmail.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Current classmap code protects class'd pr_debugs from unintended changes by "legacy" unclassed queries: # this doesn't disable all of DRM_UT_* categories echo "-p" > /proc/dynamic_debug/control # name the class to change it - protective but tedious echo "class DRM_UT_CORE +p" > /proc/dynamic_debug/control # or do it the (old school) subsystem way echo 1 > /sys/module/drm/parameters/debug This "name the class to change it" behavior gave a modicum of protection to classmap users (ie DRM) so their debug settings aren't trivially and unintentionally altered underneath them. And by "symmetry", if they're not picked by "class FOO", then they're excluded from adjustment. This allowed all previously conceived queries to work the way they always had; ie select the same set of pr_debugs, despite the inclusion of whole new classes of pr_debugs. That had 2 downsides: 1. "name the class to change it" means that every class must be individually modified, quickly becoming long-winded and tedious to adjust all the classes in a map via >control. 2. It made the class keyword special in some sense; the other keywords skip only on explicit mismatch, otherwise the code falls thru to adjust the pr-debug site. So this patch reverts to the traditional view, it drops protection of classes from default/legacy queries. But it also refactors the skip/continue choice to allow the module defining the classmap to protect its classes from unintended alterations by legacy/class-less queries. Next: Author choice: use of DYNAMIC_DEBUG_CLASSMAP_PARAM() means they want the drm.debug style control point. We should presume they want it to reflect whats set underneath, with only "class FOO" qualified queries changing the callsites beneath. CC: jbaron@akamai.com Signed-off-by: Jim Cromie --- v3- s/slctd_/selected_/ pitch the PARAM control of protection. --- lib/dynamic_debug.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 7a60088a1b5c..54f462cf41b0 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -197,6 +197,17 @@ ddebug_find_valid_class(struct _ddebug_info const *di, const char *query_class, return NULL; } +/* + * classmaps-v1 protected classes from changes by legacy commands + * (those selecting _DPRINTK_CLASS_DFLT by omission), v2 undoes that + * special treatment. State so explicitly. Later we could give + * modules the choice to protect their classes or to keep v2 behavior. + */ +static inline bool ddebug_client_module_protects_classes(const struct ddebug_table *dt) +{ + return false; +} + /* * Search the tables for _ddebug's which match the given `query' and * apply the `flags' and `mask' to them. Returns number of matching @@ -211,7 +222,7 @@ static int ddebug_change(const struct ddebug_query *query, struct flag_settings unsigned int nfound = 0; struct flagsbuf fbuf, nbuf; struct _ddebug_class_map *map = NULL; - int valid_class; + int selected_class; /* search for matching ddebugs */ mutex_lock(&ddebug_lock); @@ -224,21 +235,25 @@ static int ddebug_change(const struct ddebug_query *query, struct flag_settings if (query->class_string) { map = ddebug_find_valid_class(&dt->info, query->class_string, - &valid_class); + &selected_class); if (!map) continue; } else { - /* constrain query, do not touch class'd callsites */ - valid_class = _DPRINTK_CLASS_DFLT; + selected_class = _DPRINTK_CLASS_DFLT; } for (i = 0; i < dt->info.descs.len; i++) { struct _ddebug *dp = &dt->info.descs.start[i]; - /* match site against query-class */ - if (dp->class_id != valid_class) - continue; - + if (dp->class_id != selected_class) { + if (query->class_string) + /* site.class != given class */ + continue; + /* legacy query, class'd site */ + else if (ddebug_client_module_protects_classes(dt)) + continue; + /* allow change on class'd pr_debug */ + } /* match against the source filename */ if (query->filename && !match_wildcard(query->filename, dp->filename) &&