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 static 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
;
24 static struct ctl_table kern_do_mounts_initrd_table
[] = {
26 .procname
= "real-root-dev",
27 .data
= &real_root_dev
,
28 .maxlen
= sizeof(int),
30 .proc_handler
= proc_dointvec
,
35 static __init
int kernel_do_mounts_initrd_sysctls_init(void)
37 register_sysctl_init("kernel", kern_do_mounts_initrd_table
);
40 late_initcall(kernel_do_mounts_initrd_sysctls_init
);
41 #endif /* CONFIG_SYSCTL */
43 static int __init
no_initrd(char *str
)
49 __setup("noinitrd", no_initrd
);
51 static int __init
early_initrdmem(char *p
)
57 start
= memparse(p
, &endp
);
59 size
= memparse(endp
+ 1, NULL
);
61 phys_initrd_start
= start
;
62 phys_initrd_size
= size
;
66 early_param("initrdmem", early_initrdmem
);
68 static int __init
early_initrd(char *p
)
70 return early_initrdmem(p
);
72 early_param("initrd", early_initrd
);
74 static int __init
init_linuxrc(struct subprocess_info
*info
, struct cred
*new)
76 ksys_unshare(CLONE_FS
| CLONE_FILES
);
78 /* move initrd over / and chdir/chroot in initrd root */
80 init_mount(".", "/", NULL
, MS_MOVE
, NULL
);
86 static void __init
handle_initrd(void)
88 struct subprocess_info
*info
;
89 static char *argv
[] = { "linuxrc", NULL
, };
90 extern char *envp_init
[];
93 pr_warn("using deprecated initrd support, will be removed in 2021.\n");
95 real_root_dev
= new_encode_dev(ROOT_DEV
);
96 create_dev("/dev/root.old", Root_RAM0
);
97 /* mount initrd on rootfs' /root */
98 mount_block_root("/dev/root.old", root_mountflags
& ~MS_RDONLY
);
99 init_mkdir("/old", 0700);
103 * In case that a resume from disk is carried out by linuxrc or one of
104 * its children, we need to tell the freezer not to wait for us.
106 current
->flags
|= PF_FREEZER_SKIP
;
108 info
= call_usermodehelper_setup("/linuxrc", argv
, envp_init
,
109 GFP_KERNEL
, init_linuxrc
, NULL
, NULL
);
112 call_usermodehelper_exec(info
, UMH_WAIT_PROC
);
114 current
->flags
&= ~PF_FREEZER_SKIP
;
116 /* move initrd to rootfs' /old */
117 init_mount("..", ".", NULL
, MS_MOVE
, NULL
);
118 /* switch root and cwd back to / of rootfs */
121 if (new_decode_dev(real_root_dev
) == Root_RAM0
) {
127 ROOT_DEV
= new_decode_dev(real_root_dev
);
130 printk(KERN_NOTICE
"Trying to move old root to /initrd ... ");
131 error
= init_mount("/old", "/root/initrd", NULL
, MS_MOVE
, NULL
);
135 if (error
== -ENOENT
)
136 printk("/initrd does not exist. Ignored.\n");
139 printk(KERN_NOTICE
"Unmounting old root\n");
140 init_umount("/old", MNT_DETACH
);
144 bool __init
initrd_load(void)
147 create_dev("/dev/ram", Root_RAM0
);
149 * Load the initrd data into /dev/ram0. Execute it as initrd
150 * unless /dev/ram0 is supposed to be our actual root device,
151 * in that case the ram disk is just set up here, and gets
152 * mounted in the normal path.
154 if (rd_load_image("/initrd.image") && ROOT_DEV
!= Root_RAM0
) {
155 init_unlink("/initrd.image");
160 init_unlink("/initrd.image");