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1// SPDX-License-Identifier: GPL-2.02#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;17static unsigned 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 23#ifdef CONFIG_SYSCTL24static struct ctl_table kern_do_mounts_initrd_table[] = {25 {26 .procname = "real-root-dev",27 .data = &real_root_dev,28 .maxlen = sizeof(int),29 .mode = 0644,30 .proc_handler = proc_dointvec,31 },32};33 34static __init int kernel_do_mounts_initrd_sysctls_init(void)35{36 register_sysctl_init("kernel", kern_do_mounts_initrd_table);37 return 0;38}39late_initcall(kernel_do_mounts_initrd_sysctls_init);40#endif /* CONFIG_SYSCTL */41 42static int __init no_initrd(char *str)43{44 mount_initrd = 0;45 return 1;46}47 48__setup("noinitrd", no_initrd);49 50static int __init early_initrdmem(char *p)51{52 phys_addr_t start;53 unsigned long size;54 char *endp;55 56 start = memparse(p, &endp);57 if (*endp == ',') {58 size = memparse(endp + 1, NULL);59 60 phys_initrd_start = start;61 phys_initrd_size = size;62 }63 return 0;64}65early_param("initrdmem", early_initrdmem);66 67static int __init early_initrd(char *p)68{69 return early_initrdmem(p);70}71early_param("initrd", early_initrd);72 73static int __init init_linuxrc(struct subprocess_info *info, struct cred *new)74{75 ksys_unshare(CLONE_FS | CLONE_FILES);76 console_on_rootfs();77 /* move initrd over / and chdir/chroot in initrd root */78 init_chdir("/root");79 init_mount(".", "/", NULL, MS_MOVE, NULL);80 init_chroot(".");81 ksys_setsid();82 return 0;83}84 85static HWJS_SUSPENDS void __init handle_initrd(char *root_device_name)86{87 struct subprocess_info *info;88 static char *argv[] = { "linuxrc", NULL, };89 extern char *envp_init[];90 int error;91 92 pr_warn("using deprecated initrd support, will be removed in 2021.\n");93 94 real_root_dev = new_encode_dev(ROOT_DEV);95 create_dev("/dev/root.old", Root_RAM0);96 /* mount initrd on rootfs' /root */97 mount_root_generic("/dev/root.old", root_device_name,98 root_mountflags & ~MS_RDONLY);99 init_mkdir("/old", 0700);100 init_chdir("/old");101 102 info = call_usermodehelper_setup("/linuxrc", argv, envp_init,103 GFP_KERNEL, init_linuxrc, NULL, NULL);104 if (!info)105 return;106 call_usermodehelper_exec(info, UMH_WAIT_PROC|UMH_FREEZABLE);107 108 /* move initrd to rootfs' /old */109 init_mount("..", ".", NULL, MS_MOVE, NULL);110 /* switch root and cwd back to / of rootfs */111 init_chroot("..");112 113 if (new_decode_dev(real_root_dev) == Root_RAM0) {114 init_chdir("/old");115 return;116 }117 118 init_chdir("/");119 ROOT_DEV = new_decode_dev(real_root_dev);120 mount_root(root_device_name);121 122 printk(KERN_NOTICE "Trying to move old root to /initrd ... ");123 error = init_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);124 if (!error)125 printk("okay\n");126 else {127 if (error == -ENOENT)128 printk("/initrd does not exist. Ignored.\n");129 else130 printk("failed\n");131 printk(KERN_NOTICE "Unmounting old root\n");132 init_umount("/old", MNT_DETACH);133 }134}135 136bool __init initrd_load(char *root_device_name)137{138 if (mount_initrd) {139 create_dev("/dev/ram", Root_RAM0);140 /*141 * Load the initrd data into /dev/ram0. Execute it as initrd142 * unless /dev/ram0 is supposed to be our actual root device,143 * in that case the ram disk is just set up here, and gets144 * mounted in the normal path.145 */146 if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {147 init_unlink("/initrd.image");148 handle_initrd(root_device_name);149 return true;150 }151 }152 init_unlink("/initrd.image");153 return false;154}155