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_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 } 46 early_param("initrdmem", early_initrdmem); 47 48 /* 49 * This is here as the initrd keyword has been in use since 11/2018 50 * on ARM, PowerPC, and MIPS. 51 * It should not be; it is reserved for bootloaders. 52 */ 53 static int __init early_initrd(char *p) 54 { 55 return early_initrdmem(p); 56 } 57 early_param("initrd", early_initrd); 58 59 static int init_linuxrc(struct subprocess_info *info, struct cred *new) 60 { 61 ksys_unshare(CLONE_FS | CLONE_FILES); 62 console_on_rootfs(); 63 /* move initrd over / and chdir/chroot in initrd root */ 64 ksys_chdir("/root"); 65 do_mount(".", "/", NULL, MS_MOVE, NULL); 66 ksys_chroot("."); 67 ksys_setsid(); 68 return 0; 69 } 70 71 static void __init handle_initrd(void) 72 { 73 struct subprocess_info *info; 74 static char *argv[] = { "linuxrc", NULL, }; 75 extern char *envp_init[]; 76 int error; 77 78 real_root_dev = new_encode_dev(ROOT_DEV); 79 create_dev("/dev/root.old", Root_RAM0); 80 /* mount initrd on rootfs' /root */ 81 mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY); 82 ksys_mkdir("/old", 0700); 83 ksys_chdir("/old"); 84 85 /* 86 * In case that a resume from disk is carried out by linuxrc or one of 87 * its children, we need to tell the freezer not to wait for us. 88 */ 89 current->flags |= PF_FREEZER_SKIP; 90 91 info = call_usermodehelper_setup("/linuxrc", argv, envp_init, 92 GFP_KERNEL, init_linuxrc, NULL, NULL); 93 if (!info) 94 return; 95 call_usermodehelper_exec(info, UMH_WAIT_PROC); 96 97 current->flags &= ~PF_FREEZER_SKIP; 98 99 /* move initrd to rootfs' /old */ 100 do_mount("..", ".", NULL, MS_MOVE, NULL); 101 /* switch root and cwd back to / of rootfs */ 102 ksys_chroot(".."); 103 104 if (new_decode_dev(real_root_dev) == Root_RAM0) { 105 ksys_chdir("/old"); 106 return; 107 } 108 109 ksys_chdir("/"); 110 ROOT_DEV = new_decode_dev(real_root_dev); 111 mount_root(); 112 113 printk(KERN_NOTICE "Trying to move old root to /initrd ... "); 114 error = do_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL); 115 if (!error) 116 printk("okay\n"); 117 else { 118 int fd = ksys_open("/dev/root.old", O_RDWR, 0); 119 if (error == -ENOENT) 120 printk("/initrd does not exist. Ignored.\n"); 121 else 122 printk("failed\n"); 123 printk(KERN_NOTICE "Unmounting old root\n"); 124 ksys_umount("/old", MNT_DETACH); 125 printk(KERN_NOTICE "Trying to free ramdisk memory ... "); 126 if (fd < 0) { 127 error = fd; 128 } else { 129 error = ksys_ioctl(fd, BLKFLSBUF, 0); 130 ksys_close(fd); 131 } 132 printk(!error ? "okay\n" : "failed\n"); 133 } 134 } 135 136 bool __init initrd_load(void) 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 ksys_unlink("/initrd.image"); 148 handle_initrd(); 149 return true; 150 } 151 } 152 ksys_unlink("/initrd.image"); 153 return false; 154 } 155