1 files changed, 49 insertions, 0 deletions

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 8675717c0f16..8fba40179305 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -862,6 +862,41 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 }
 EXPORT_SYMBOL_GPL(ddebug_add_module);
 
+/* handle both dyndbg=".." and $module.dyndbg=".." params at boot */
+static int ddebug_dyndbg_boot_param_cb(char *param, char *val,
+				const char *unused)
+{
+	const char *modname = NULL;
+	char *sep;
+
+	sep = strchr(param, '.');
+	if (sep) {
+		*sep = '\0';
+		modname = param;
+		param = sep + 1;
+	}
+	if (strcmp(param, "dyndbg"))
+		return 0; /* skip all other params w/o error */
+
+	vpr_info("module: %s %s=\"%s\"\n", modname, param, val);
+
+	ddebug_exec_queries(val ? val : "+p");
+	return 0; /* query failure shouldnt stop module load */
+}
+
+/* handle dyndbg args to modprobe */
+int ddebug_dyndbg_module_param_cb(char *param, char *val, const char *doing)
+{
+	if (strcmp(param, "dyndbg"))
+		return -ENOENT;
+
+	vpr_info("module: %s %s=\"%s\"\n", doing, param, val);
+
+	ddebug_exec_queries((val ? val : "+p"));
+
+	return 0; /* query failure shouldnt stop module load */
+}
+
 static void ddebug_table_free(struct ddebug_table *dt)
 {
 	list_del_init(&dt->link);
@@ -929,6 +964,7 @@ static int __init dynamic_debug_init(void)
 {
 	struct _ddebug *iter, *iter_start;
 	const char *modname = NULL;
+	char *cmdline;
 	int ret = 0;
 	int n = 0;
 
@@ -967,6 +1003,18 @@ static int __init dynamic_debug_init(void)
 		/* keep tables even on ddebug_query parse error */
 		ret = 0;
 	}
+	/* now that ddebug tables are loaded, process all boot args
+	 * again to find and activate queries given in dyndbg params.
+	 * While this has already been done for known boot params, it
+	 * ignored the unknown ones (dyndbg in particular).  Reusing
+	 * parse_args avoids ad-hoc parsing.  This will also attempt
+	 * to activate queries for not-yet-loaded modules, which is
+	 * slightly noisy if verbose, but harmless.
+	 */
+	cmdline = kstrdup(saved_command_line, GFP_KERNEL);
+	parse_args("dyndbg params", cmdline, NULL,
+		   0, 0, 0, &ddebug_dyndbg_boot_param_cb);
+	kfree(cmdline);
 
 out_free:
 	if (ret)
@@ -977,5 +1025,6 @@ out_free:
 }
 /* Allow early initialization for boot messages via boot param */
 arch_initcall(dynamic_debug_init);
+
 /* Debugfs setup must be done later */
 module_init(dynamic_debug_init_debugfs);