Dynamic Debug: Introduce ddebug_query= boot parameter
Dynamic debug lacks the ability to enable debug messages at boot time.
One could patch initramfs or service startup scripts to write to
/sys/../dynamic_debug/control, but this sucks.
This patch makes it possible to pass a query in the same format one can
write to /sys/../dynamic_debug/control via boot param.
When dynamic debug gets initialized, this query will automatically be
applied.
Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: jbaron@redhat.com
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 84d103c4..44ce66b 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -450,6 +450,19 @@
return 0;
}
+static __initdata char ddebug_setup_string[1024];
+static __init int ddebug_setup_query(char *str)
+{
+ if (strlen(str) >= 1024) {
+ pr_warning("ddebug boot param string too large\n");
+ return 0;
+ }
+ strcpy(ddebug_setup_string, str);
+ return 1;
+}
+
+__setup("ddebug_query=", ddebug_setup_query);
+
/*
* File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
* command text from userspace, parses and executes it.
@@ -769,6 +782,18 @@
}
ret = ddebug_add_module(iter_start, n, modname);
}
+
+ /* ddebug_query boot param got passed -> set it up */
+ if (ddebug_setup_string[0] != '\0') {
+ ret = ddebug_exec_query(ddebug_setup_string);
+ if (ret)
+ pr_warning("Invalid ddebug boot param %s",
+ ddebug_setup_string);
+ else
+ pr_info("ddebug initialized with string %s",
+ ddebug_setup_string);
+ }
+
out_free:
if (ret) {
ddebug_remove_all_tables();