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 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 static int __init no_initrd(char *str) 24 { 25 mount_initrd = 0; 26 return 1; 27 } 28 29 __setup("noinitrd", no_initrd); 30 31 static int __init early_initrd(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 } 46 early_param("initrd", early_initrd); 47 48 static int init_linuxrc(struct subprocess_info *info, struct cred *new) 49 { 50 ksys_unshare(CLONE_FS | CLONE_FILES); 51 /* stdin/stdout/stderr for /linuxrc */ 52 ksys_open("/dev/console", O_RDWR, 0); 53 ksys_dup(0); 54 ksys_dup(0); 55 /* move initrd over / and chdir/chroot in initrd root */ 56 ksys_chdir("/root"); 57 ksys_mount(".", "/", NULL, MS_MOVE, NULL); 58 ksys_chroot("."); 59 ksys_setsid(); 60 return 0; 61 } 62 63 static void __init handle_initrd(void) 64 { 65 struct subprocess_info *info; 66 static char *argv[] = { "linuxrc", NULL, }; 67 extern char *envp_init[]; 68 int error; 69 70 real_root_dev = new_encode_dev(ROOT_DEV); 71 create_dev("/dev/root.old", Root_RAM0); 72 /* mount initrd on rootfs' /root */ 73 mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY); 74 ksys_mkdir("/old", 0700); 75 ksys_chdir("/old"); 76 77 /* 78 * In case that a resume from disk is carried out by linuxrc or one of 79 * its children, we need to tell the freezer not to wait for us. 80 */ 81 current->flags |= PF_FREEZER_SKIP; 82 83 info = call_usermodehelper_setup("/linuxrc", argv, envp_init, 84 GFP_KERNEL, init_linuxrc, NULL, NULL); 85 if (!info) 86 return; 87 call_usermodehelper_exec(info, UMH_WAIT_PROC); 88 89 current->flags &= ~PF_FREEZER_SKIP; 90 91 /* move initrd to rootfs' /old */ 92 ksys_mount("..", ".", NULL, MS_MOVE, NULL); 93 /* switch root and cwd back to / of rootfs */ 94 ksys_chroot(".."); 95 96 if (new_decode_dev(real_root_dev) == Root_RAM0) { 97 ksys_chdir("/old"); 98 return; 99 } 100 101 ksys_chdir("/"); 102 ROOT_DEV = new_decode_dev(real_root_dev); 103 mount_root(); 104 105 printk(KERN_NOTICE "Trying to move old root to /initrd ... "); 106 error = ksys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL); 107 if (!error) 108 printk("okay\n"); 109 else { 110 int fd = ksys_open("/dev/root.old", O_RDWR, 0); 111 if (error == -ENOENT) 112 printk("/initrd does not exist. Ignored.\n"); 113 else 114 printk("failed\n"); 115 printk(KERN_NOTICE "Unmounting old root\n"); 116 ksys_umount("/old", MNT_DETACH); 117 printk(KERN_NOTICE "Trying to free ramdisk memory ... "); 118 if (fd < 0) { 119 error = fd; 120 } else { 121 error = ksys_ioctl(fd, BLKFLSBUF, 0); 122 ksys_close(fd); 123 } 124 printk(!error ? "okay\n" : "failed\n"); 125 } 126 } 127 128 bool __init initrd_load(void) 129 { 130 if (mount_initrd) { 131 create_dev("/dev/ram", Root_RAM0); 132 /* 133 * Load the initrd data into /dev/ram0. Execute it as initrd 134 * unless /dev/ram0 is supposed to be our actual root device, 135 * in that case the ram disk is just set up here, and gets 136 * mounted in the normal path. 137 */ 138 if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) { 139 ksys_unlink("/initrd.image"); 140 handle_initrd(); 141 return true; 142 } 143 } 144 ksys_unlink("/initrd.image"); 145 return false; 146 } 147