diff -urN linux-2.4.32-procboot/fs/proc/proc_misc.c linux-2.4.32-bootdev/fs/proc/proc_misc.c
--- linux-2.4.32-procboot/fs/proc/proc_misc.c	2004-08-08 01:26:06.000000000 +0200
+++ linux-2.4.32-bootdev/fs/proc/proc_misc.c	2005-11-22 10:17:03.000000000 +0100
@@ -457,6 +457,16 @@
 	return proc_calc_metrics(page, start, off, count, eof, len);
 }
 
+static int boot_bootdev_read_proc(char *page, char **start, off_t off,
+				 int count, int *eof, void *data)
+{
+	extern char saved_bootdev[];
+	int len = 0;
+
+	proc_sprintf(page, &off, &len, "%s\n", saved_bootdev);
+	return proc_calc_metrics(page, start, off, count, eof, len);
+}
+
 #ifdef CONFIG_SGI_DS1286
 static int ds1286_read_proc(char *page, char **start, off_t off,
 				 int count, int *eof, void *data)
@@ -627,6 +637,9 @@
 	for (p = simple_ones; p->name; p++)
 		create_proc_read_entry(p->name, 0, NULL, p->read_proc, NULL);
 
+	create_proc_read_entry("bootdev", S_IRUGO, proc_boot, \
+				boot_bootdev_read_proc, NULL);
+
 	proc_symlink("mounts", NULL, "self/mounts");
 
 	/* And now for trickier ones */
diff -urN linux-2.4.32-procboot/init/main.c linux-2.4.32-bootdev/init/main.c
--- linux-2.4.32-procboot/init/main.c	2004-11-17 12:54:22.000000000 +0100
+++ linux-2.4.32-bootdev/init/main.c	2005-11-22 10:29:35.000000000 +0100
@@ -227,6 +227,17 @@
 __setup("debug", debug_kernel);
 __setup("quiet", quiet_kernel);
 
+/* 32 chars should be enough to save a full path to a boot device */
+#define MAX_BOOTDEV_LEN 32
+char saved_bootdev[MAX_BOOTDEV_LEN] = "";
+static int __init parse_bootdev(char *str)
+{
+	strncpy(saved_bootdev, str, MAX_BOOTDEV_LEN-1);
+	saved_bootdev[MAX_BOOTDEV_LEN-1] = '\0';
+	return 1;
+}
+__setup("bootdev=", parse_bootdev);
+
 /*
  * This is a simple kernel command line parsing function: it parses
  * the command line, and fills in the arguments/environment to init