dyndbg: 1st port of bitmap-to-query code

broken still, needs fixup on undefined format_class_prefixes, which
could become a declarative interface; an ordered list of string
prefixes maps bits 0...N-1.  So it needs sorting.

lib/dynamic_debug.c

@@ -1150,3 +1150,50 @@ early_initcall(dynamic_debug_init);
 
 /* Debugfs setup must be done later */
 fs_initcall(dynamic_debug_init_control);
+
+static int param_set_dyndbg(const char *instr, const struct kernel_param *kp)
+{
+	unsigned int val;
+	unsigned long changes, result;
+	int rc, chgct = 0, totct = 0, bitpos;
+	char query[OUR_QUERY_SIZE];
+
+	rc = kstrtouint(instr, 0, &val);
+	if (rc) {
+		pr_err("%s: failed\n", __func__);
+		return -EINVAL;
+	}
+	result = val;
+	// changes = result ^ __drm_debug;
+
+	pr_debug("changes:0x%lx from result:0x%lx\n", changes, result);
+
+	for_each_set_bit(bitpos, &changes, ARRAY_SIZE(format_class_prefixes)) {
+
+		sprintf(query, "format '^%s' %cp", format_class_prefixes[bitpos],
+			test_bit(bitpos, &result) ? '+' : '-');
+
+		chgct = dynamic_debug_exec_queries(query, "drm*");
+		if (chgct < 0) {
+			pr_err("%s: exec err:%d on: %s\n", __func__, chgct, query);
+			continue;
+		}
+		pr_debug("change ct:%d on %s\n", chgct, query);
+		totct += chgct;
+	}
+	pr_debug("total changes: %d\n", totct);
+	//__drm_debug = result;
+	return 0;
+}
+
+static int param_get_dyndbg(char *buffer, const struct kernel_param *kp)
+{
+	pr_debug("debug-val:0x%x\n", //__drm_debug
+		 *((unsigned int *)kp->arg));
+	return scnprintf(buffer, PAGE_SIZE, "%u\n",
+			 *((unsigned int *)kp->arg));
+}
+static const struct kernel_param_ops param_ops_debug = {
+	.set = param_set_dyndbg,
+	.get = param_get_dyndbg,
+};