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 phys_addr_t phys_initrd_start __initdata;
21 unsigned long phys_initrd_size __initdata;
23 static int __init no_initrd(char *str)
29 __setup("noinitrd", no_initrd);
31 static int __init early_initrdmem(char *p)
37 start = memparse(p, &endp);
39 size = memparse(endp + 1, NULL);
41 phys_initrd_start = start;
42 phys_initrd_size = size;
46 early_param("initrdmem", early_initrdmem);
49 * This is here as the initrd keyword has been in use since 11/2018
50 * on ARM, PowerPC, and MIPS.
51 * It should not be; it is reserved for bootloaders.
53 static int __init early_initrd(char *p)
55 return early_initrdmem(p);
57 early_param("initrd", early_initrd);
59 static int init_linuxrc(struct subprocess_info *info, struct cred *new)
61 ksys_unshare(CLONE_FS | CLONE_FILES);
63 /* move initrd over / and chdir/chroot in initrd root */
65 do_mount(".", "/", NULL, MS_MOVE, NULL);
71 static void __init handle_initrd(void)
73 struct subprocess_info *info;
74 static char *argv[] = { "linuxrc", NULL, };
75 extern char *envp_init[];
78 real_root_dev = new_encode_dev(ROOT_DEV);
79 create_dev("/dev/root.old", Root_RAM0);
80 /* mount initrd on rootfs' /root */
81 mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
82 ksys_mkdir("/old", 0700);
86 * In case that a resume from disk is carried out by linuxrc or one of
87 * its children, we need to tell the freezer not to wait for us.
89 current->flags |= PF_FREEZER_SKIP;
91 info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
92 GFP_KERNEL, init_linuxrc, NULL, NULL);
95 call_usermodehelper_exec(info, UMH_WAIT_PROC);
97 current->flags &= ~PF_FREEZER_SKIP;
99 /* move initrd to rootfs' /old */
100 do_mount("..", ".", NULL, MS_MOVE, NULL);
101 /* switch root and cwd back to / of rootfs */
104 if (new_decode_dev(real_root_dev) == Root_RAM0) {
110 ROOT_DEV = new_decode_dev(real_root_dev);
113 printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
114 error = do_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
118 int fd = ksys_open("/dev/root.old", O_RDWR, 0);
119 if (error == -ENOENT)
120 printk("/initrd does not exist. Ignored.\n");
123 printk(KERN_NOTICE "Unmounting old root\n");
124 ksys_umount("/old", MNT_DETACH);
125 printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
129 error = ksys_ioctl(fd, BLKFLSBUF, 0);
132 printk(!error ? "okay\n" : "failed\n");
136 bool __init initrd_load(void)
139 create_dev("/dev/ram", Root_RAM0);
141 * Load the initrd data into /dev/ram0. Execute it as initrd
142 * unless /dev/ram0 is supposed to be our actual root device,
143 * in that case the ram disk is just set up here, and gets
144 * mounted in the normal path.
146 if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
147 ksys_unlink("/initrd.image");
152 ksys_unlink("/initrd.image");