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 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; 19 20 phys_addr_t phys_initrd_start __initdata; 21 unsigned long phys_initrd_size __initdata; 22 23 #ifdef CONFIG_SYSCTL 24 static 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 34 static __init int kernel_do_mounts_initrd_sysctls_init(void) 35 { 36 register_sysctl_init("kernel", kern_do_mounts_initrd_table); 37 return 0; 38 } 39 late_initcall(kernel_do_mounts_initrd_sysctls_init); 40 #endif /* CONFIG_SYSCTL */ 41 42 static int __init no_initrd(char *str) 43 { 44 mount_initrd = 0; 45 return 1; 46 } 47 48 __setup("noinitrd", no_initrd); 49 50 static 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 } 65 early_param("initrdmem", early_initrdmem); 66 67 static int __init early_initrd(char *p) 68 { 69 return early_initrdmem(p); 70 } 71 early_param("initrd", early_initrd); 72 73 static 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 85 static 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 else 130 printk("failed\n"); 131 printk(KERN_NOTICE "Unmounting old root\n"); 132 init_umount("/old", MNT_DETACH); 133 } 134 } 135 136 bool __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 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. 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