1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/unistd.h>
3 #include <linux/kernel.h>
5 #include <linux/minix_fs.h>
6 #include <linux/romfs_fs.h>
7 #include <linux/initrd.h>
8 #include <linux/sched.h>
9 #include <linux/freezer.h>
10 #include <linux/kmod.h>
11 #include <uapi/linux/mount.h>
13 #include "do_mounts.h"
15 unsigned long initrd_start, initrd_end;
16 int initrd_below_start_ok;
17 unsigned int real_root_dev; /* do_proc_dointvec cannot handle kdev_t */
18 static int __initdata mount_initrd = 1;
20 static int __init no_initrd(char *str)
26 __setup("noinitrd", no_initrd);
28 static int init_linuxrc(struct subprocess_info *info, struct cred *new)
30 ksys_unshare(CLONE_FS | CLONE_FILES);
31 /* stdin/stdout/stderr for /linuxrc */
32 ksys_open("/dev/console", O_RDWR, 0);
35 /* move initrd over / and chdir/chroot in initrd root */
37 ksys_mount(".", "/", NULL, MS_MOVE, NULL);
43 static void __init handle_initrd(void)
45 struct subprocess_info *info;
46 static char *argv[] = { "linuxrc", NULL, };
47 extern char *envp_init[];
50 real_root_dev = new_encode_dev(ROOT_DEV);
51 create_dev("/dev/root.old", Root_RAM0);
52 /* mount initrd on rootfs' /root */
53 mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
54 ksys_mkdir("/old", 0700);
57 /* try loading default modules from initrd */
58 load_default_modules();
61 * In case that a resume from disk is carried out by linuxrc or one of
62 * its children, we need to tell the freezer not to wait for us.
64 current->flags |= PF_FREEZER_SKIP;
66 info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
67 GFP_KERNEL, init_linuxrc, NULL, NULL);
70 call_usermodehelper_exec(info, UMH_WAIT_PROC);
72 current->flags &= ~PF_FREEZER_SKIP;
74 /* move initrd to rootfs' /old */
75 ksys_mount("..", ".", NULL, MS_MOVE, NULL);
76 /* switch root and cwd back to / of rootfs */
79 if (new_decode_dev(real_root_dev) == Root_RAM0) {
85 ROOT_DEV = new_decode_dev(real_root_dev);
88 printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
89 error = ksys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
93 int fd = ksys_open("/dev/root.old", O_RDWR, 0);
95 printk("/initrd does not exist. Ignored.\n");
98 printk(KERN_NOTICE "Unmounting old root\n");
99 ksys_umount("/old", MNT_DETACH);
100 printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
104 error = ksys_ioctl(fd, BLKFLSBUF, 0);
107 printk(!error ? "okay\n" : "failed\n");
111 bool __init initrd_load(void)
114 create_dev("/dev/ram", Root_RAM0);
116 * Load the initrd data into /dev/ram0. Execute it as initrd
117 * unless /dev/ram0 is supposed to be our actual root device,
118 * in that case the ram disk is just set up here, and gets
119 * mounted in the normal path.
121 if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
122 ksys_unlink("/initrd.image");
127 ksys_unlink("/initrd.image");