init: bootconfig: Remove all bootconfig data when the init memory is removed

Since the bootconfig is used only in the init functions,
it doesn't need to keep the data after boot. Free it when
the init memory is removed.

Link: https://lkml.kernel.org/r/163077084958.222577.5924961258513004428.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Author: mhiramat

init/main.c

@@ -468,7 +468,12 @@ static void __init setup_boot_config(void)
 	return;
 }
 
-#else
+static void __init exit_boot_config(void)
+{
+	xbc_destroy_all();
+}
+
+#else	/* !CONFIG_BOOT_CONFIG */
 
 static void __init setup_boot_config(void)
 {
@@ -481,7 +486,11 @@ static int __init warn_bootconfig(char *str)
 	pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOT_CONFIG is not set.\n");
 	return 0;
 }
-#endif
+
+#define exit_boot_config()	do {} while (0)
+
+#endif	/* CONFIG_BOOT_CONFIG */
+
 early_param("bootconfig", warn_bootconfig);
 
 /* Change NUL term back to "=", to make "param" the whole string. */
@@ -1493,6 +1502,7 @@ static int __ref kernel_init(void *unused)
 	kprobe_free_init_mem();
 	ftrace_free_init_mem();
 	kgdb_free_init_mem();
+	exit_boot_config();
 	free_initmem();
 	mark_readonly();