1// SPDX-License-Identifier: GPL-2.0
2#include <linux/unistd.h>
3#include <linux/kernel.h>
4#include <linux/fs.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>
12
13#include "do_mounts.h"
14
15unsigned long initrd_start, initrd_end;
16int initrd_below_start_ok;
17unsigned int real_root_dev;	/* do_proc_dointvec cannot handle kdev_t */
18static int __initdata mount_initrd = 1;
19
20phys_addr_t phys_initrd_start __initdata;
21unsigned long phys_initrd_size __initdata;
22
23static int __init no_initrd(char *str)
24{
25	mount_initrd = 0;
26	return 1;
27}
28
29__setup("noinitrd", no_initrd);
30
31static int __init early_initrdmem(char *p)
32{
33	phys_addr_t start;
34	unsigned long size;
35	char *endp;
36
37	start = memparse(p, &endp);
38	if (*endp == ',') {
39		size = memparse(endp + 1, NULL);
40
41		phys_initrd_start = start;
42		phys_initrd_size = size;
43	}
44	return 0;
45}
46early_param("initrdmem", early_initrdmem);
47
48static int __init early_initrd(char *p)
49{
50	return early_initrdmem(p);
51}
52early_param("initrd", early_initrd);
53
54static int __init init_linuxrc(struct subprocess_info *info, struct cred *new)
55{
56	ksys_unshare(CLONE_FS | CLONE_FILES);
57	console_on_rootfs();
58	/* move initrd over / and chdir/chroot in initrd root */
59	init_chdir("/root");
60	init_mount(".", "/", NULL, MS_MOVE, NULL);
61	init_chroot(".");
62	ksys_setsid();
63	return 0;
64}
65
66static void __init handle_initrd(void)
67{
68	struct subprocess_info *info;
69	static char *argv[] = { "linuxrc", NULL, };
70	extern char *envp_init[];
71	int error;
72
73	pr_warn("using deprecated initrd support, will be removed in 2021.\n");
74
75	real_root_dev = new_encode_dev(ROOT_DEV);
76	create_dev("/dev/root.old", Root_RAM0);
77	/* mount initrd on rootfs' /root */
78	mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
79	init_mkdir("/old", 0700);
80	init_chdir("/old");
81
82	/*
83	 * In case that a resume from disk is carried out by linuxrc or one of
84	 * its children, we need to tell the freezer not to wait for us.
85	 */
86	current->flags |= PF_FREEZER_SKIP;
87
88	info = call_usermodehelper_setup("/linuxrc", argv, envp_init,
89					 GFP_KERNEL, init_linuxrc, NULL, NULL);
90	if (!info)
91		return;
92	call_usermodehelper_exec(info, UMH_WAIT_PROC);
93
94	current->flags &= ~PF_FREEZER_SKIP;
95
96	/* move initrd to rootfs' /old */
97	init_mount("..", ".", NULL, MS_MOVE, NULL);
98	/* switch root and cwd back to / of rootfs */
99	init_chroot("..");
100
101	if (new_decode_dev(real_root_dev) == Root_RAM0) {
102		init_chdir("/old");
103		return;
104	}
105
106	init_chdir("/");
107	ROOT_DEV = new_decode_dev(real_root_dev);
108	mount_root();
109
110	printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
111	error = init_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
112	if (!error)
113		printk("okay\n");
114	else {
115		if (error == -ENOENT)
116			printk("/initrd does not exist. Ignored.\n");
117		else
118			printk("failed\n");
119		printk(KERN_NOTICE "Unmounting old root\n");
120		init_umount("/old", MNT_DETACH);
121	}
122}
123
124bool __init initrd_load(void)
125{
126	if (mount_initrd) {
127		create_dev("/dev/ram", Root_RAM0);
128		/*
129		 * Load the initrd data into /dev/ram0. Execute it as initrd
130		 * unless /dev/ram0 is supposed to be our actual root device,
131		 * in that case the ram disk is just set up here, and gets
132		 * mounted in the normal path.
133		 */
134		if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
135			init_unlink("/initrd.image");
136			handle_initrd();
137			return true;
138		}
139	}
140	init_unlink("/initrd.image");
141	return false;
142}
143