// SPDX-License-Identifier: GPL-2.0#include <linux/unistd.h>#include <linux/kernel.h>#include <linux/fs.h>#include <linux/minix_fs.h>#include <linux/romfs_fs.h>#include <linux/initrd.h>#include <linux/sched.h>#include <linux/freezer.h>#include <linux/kmod.h>#include <uapi/linux/mount.h> #include "do_mounts.h" unsigned long initrd_start, initrd_end;int initrd_below_start_ok;static unsigned int real_root_dev;	/* do_proc_dointvec cannot handle kdev_t */static int __initdata mount_initrd = 1; phys_addr_t phys_initrd_start __initdata;unsigned long phys_initrd_size __initdata; #ifdef CONFIG_SYSCTLstatic struct ctl_table kern_do_mounts_initrd_table[] = {	{		.procname       = "real-root-dev",		.data           = &real_root_dev,		.maxlen         = sizeof(int),		.mode           = 0644,		.proc_handler   = proc_dointvec,	},}; static __init int kernel_do_mounts_initrd_sysctls_init(void){	register_sysctl_init("kernel", kern_do_mounts_initrd_table);	return 0;}late_initcall(kernel_do_mounts_initrd_sysctls_init);#endif /* CONFIG_SYSCTL */ static int __init no_initrd(char *str){	mount_initrd = 0;	return 1;} __setup("noinitrd", no_initrd); static int __init early_initrdmem(char *p){	phys_addr_t start;	unsigned long size;	char *endp; 	start = memparse(p, &endp);	if (*endp == ',') {		size = memparse(endp + 1, NULL); 		phys_initrd_start = start;		phys_initrd_size = size;	}	return 0;}early_param("initrdmem", early_initrdmem); static int __init early_initrd(char *p){	return early_initrdmem(p);}early_param("initrd", early_initrd); static int __init init_linuxrc(struct subprocess_info *info, struct cred *new){	ksys_unshare(CLONE_FS | CLONE_FILES);	console_on_rootfs();	/* move initrd over / and chdir/chroot in initrd root */	init_chdir("/root");	init_mount(".", "/", NULL, MS_MOVE, NULL);	init_chroot(".");	ksys_setsid();	return 0;} static void __init handle_initrd(char *root_device_name){	struct subprocess_info *info;	static char *argv[] = { "linuxrc", NULL, };	extern char *envp_init[];	int error; 	pr_warn("using deprecated initrd support, will be removed in 2021.\n"); 	real_root_dev = new_encode_dev(ROOT_DEV);	create_dev("/dev/root.old", Root_RAM0);	/* mount initrd on rootfs' /root */	mount_root_generic("/dev/root.old", root_device_name,			   root_mountflags & ~MS_RDONLY);	init_mkdir("/old", 0700);	init_chdir("/old"); 	info = call_usermodehelper_setup("/linuxrc", argv, envp_init,					 GFP_KERNEL, init_linuxrc, NULL, NULL);	if (!info)		return;	call_usermodehelper_exec(info, UMH_WAIT_PROC|UMH_FREEZABLE); 	/* move initrd to rootfs' /old */	init_mount("..", ".", NULL, MS_MOVE, NULL);	/* switch root and cwd back to / of rootfs */	init_chroot(".."); 	if (new_decode_dev(real_root_dev) == Root_RAM0) {		init_chdir("/old");		return;	} 	init_chdir("/");	ROOT_DEV = new_decode_dev(real_root_dev);	mount_root(root_device_name); 	printk(KERN_NOTICE "Trying to move old root to /initrd ... ");	error = init_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);	if (!error)		printk("okay\n");	else {		if (error == -ENOENT)			printk("/initrd does not exist. Ignored.\n");		else			printk("failed\n");		printk(KERN_NOTICE "Unmounting old root\n");		init_umount("/old", MNT_DETACH);	}} bool __init initrd_load(char *root_device_name){	if (mount_initrd) {		create_dev("/dev/ram", Root_RAM0);		/*		 * Load the initrd data into /dev/ram0. Execute it as initrd		 * unless /dev/ram0 is supposed to be our actual root device,		 * in that case the ram disk is just set up here, and gets		 * mounted in the normal path.		 */		if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {			init_unlink("/initrd.image");			handle_initrd(root_device_name);			return true;		}	}	init_unlink("/initrd.image");	return false;}