linux-kernel - [PATCH v6 16/57] dyndbg: add ddebug_attach_module

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Message-Id: <20220904214134.408619-17-jim.cromie@gmail.com>
Date:   Sun,  4 Sep 2022 15:40:53 -0600
From:   Jim Cromie <jim.cromie@...il.com>
To:     jbaron@...mai.com, gregkh@...uxfoundation.org,
        dri-devel@...ts.freedesktop.org, amd-gfx@...ts.freedesktop.org,
        intel-gvt-dev@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Cc:     daniel.vetter@...ll.ch, seanpaul@...omium.org, robdclark@...il.com,
        linux@...musvillemoes.dk, joe@...ches.com,
        Jim Cromie <jim.cromie@...il.com>
Subject: [PATCH v6 16/57] dyndbg: add ddebug_attach_module_classes

Add ddebug_attach_module_classes(), call it from ddebug_add_module().
It scans the classes/section its given, finds records where the
module-name matches the module being added, and adds them to the
module's maps list.  No locking here, since the record
isn't yet linked into the ddebug_tables list.

It is called indirectly from 2 sources:

 - from load_module(), where it scans the module's __dyndbg_classes
   section, which contains DYNAMIC_DEBUG_CLASSES definitions from just
   the module.

 - from dynamic_debug_init(), where all DYNAMIC_DEBUG_CLASSES
   definitions of each builtin module have been packed together.
   This is why ddebug_attach_module_classes() checks module-name.

NOTES

Its (highly) likely that builtin classes will be ordered by module
name (just like prdbg descriptors are in the __dyndbg section).  So
the list can be replaced by a vector (ptr + length), which will work
for loaded modules too.  This would imitate whats currently done for
the _ddebug descriptors.

That said, converting to vector,len is close to pointless; a small
minority of modules will ever define a class-map, and almost all of
them will have only 1 or 2 class-maps, so theres only a couple dozen
pointers to save.  TODO: re-evaluate for lines removable.

Signed-off-by: Jim Cromie <jim.cromie@...il.com>
---
v6
. fix compile err due to reorderd commits, and missed lkp report.
. init dt->maps in ddebug_add_module, prior to ddebug_attach_module_classes
---
 lib/dynamic_debug.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index fb31a1a2fc3f..b71efd0b491d 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -45,7 +45,7 @@ extern struct ddebug_class_map __start___dyndbg_classes[];
 extern struct ddebug_class_map __stop___dyndbg_classes[];
 
 struct ddebug_table {
-	struct list_head link;
+	struct list_head link, maps;
 	const char *mod_name;
 	unsigned int num_ddebugs;
 	struct _ddebug *ddebugs;
@@ -921,6 +921,32 @@ static const struct proc_ops proc_fops = {
 	.proc_write = ddebug_proc_write
 };
 
+static void ddebug_attach_module_classes(struct ddebug_table *dt,
+					 struct ddebug_class_map *classes,
+					 int num_classes)
+{
+	struct ddebug_class_map *cm;
+	int i, j, ct = 0;
+
+	for (cm = classes, i = 0; i < num_classes; i++, cm++) {
+
+		if (!strcmp(cm->mod_name, dt->mod_name)) {
+
+			v2pr_info("class[%d]: module:%s base:%d len:%d ty:%d\n", i,
+				  cm->mod_name, cm->base, cm->length, cm->map_type);
+
+			for (j = 0; j < cm->length; j++)
+				v3pr_info(" %d: %d %s\n", j + cm->base, j,
+					  cm->class_names[j]);
+
+			list_add(&cm->link, &dt->maps);
+			ct++;
+		}
+	}
+	if (ct)
+		vpr_info("module:%s attached %d classes\n", dt->mod_name, ct);
+}
+
 /*
  * Allocate a new ddebug_table for the given module
  * and add it to the global list.
@@ -952,6 +978,10 @@ static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base,
 	dt->num_ddebugs = di->num_descs;
 
 	INIT_LIST_HEAD(&dt->link);
+	INIT_LIST_HEAD(&dt->maps);
+
+	if (di->classes && di->num_classes)
+		ddebug_attach_module_classes(dt, di->classes, di->num_classes);
 
 	mutex_lock(&ddebug_lock);
 	list_add_tail(&dt->link, &ddebug_tables);
-- 
2.37.2