diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 3d5cd7a09b2..d2f0c67ba1f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1174,6 +1174,11 @@ running once the system is up.
 			New name for the ramdisk parameter.
 			See Documentation/ramdisk.txt.
 
+	rdinit=		[KNL]
+			Format: <full_path>
+			Run specified binary instead of /init from the ramdisk,
+			used for early userspace startup. See initrd.
+
 	reboot=		[BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
 			Format: <reboot_mode>[,<reboot_mode2>[,...]]
 			See arch/*/kernel/reboot.c.
diff --git a/init/main.c b/init/main.c
index e4dbcbcd26c..f142d403534 100644
--- a/init/main.c
+++ b/init/main.c
@@ -123,6 +123,7 @@ extern void softirq_init(void);
 char saved_command_line[COMMAND_LINE_SIZE];
 
 static char *execute_command;
+static char *ramdisk_execute_command;
 
 /* Setup configured maximum number of CPUs to activate */
 static unsigned int max_cpus = NR_CPUS;
@@ -297,6 +298,18 @@ static int __init init_setup(char *str)
 }
 __setup("init=", init_setup);
 
+static int __init rdinit_setup(char *str)
+{
+	unsigned int i;
+
+	ramdisk_execute_command = str;
+	/* See "auto" comment in init_setup */
+	for (i = 1; i < MAX_INIT_ARGS; i++)
+		argv_init[i] = NULL;
+	return 1;
+}
+__setup("rdinit=", rdinit_setup);
+
 extern void setup_arch(char **);
 
 #ifndef CONFIG_SMP
@@ -681,10 +694,14 @@ static int init(void * unused)
 	 * check if there is an early userspace init.  If yes, let it do all
 	 * the work
 	 */
-	if (sys_access((const char __user *) "/init", 0) == 0)
-		execute_command = "/init";
-	else
+
+	if (!ramdisk_execute_command)
+		ramdisk_execute_command = "/init";
+
+	if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
+		ramdisk_execute_command = NULL;
 		prepare_namespace();
+	}
 
 	/*
 	 * Ok, we have completed the initial bootup, and
@@ -701,7 +718,13 @@ static int init(void * unused)
 
 	(void) sys_dup(0);
 	(void) sys_dup(0);
-	
+
+	if (ramdisk_execute_command) {
+		run_init_process(ramdisk_execute_command);
+		printk(KERN_WARNING "Failed to execute %s\n",
+				ramdisk_execute_command);
+	}
+
 	/*
 	 * We try each of these until one succeeds.
 	 *