1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/module.h> 3 #include <linux/sched.h> 4 #include <linux/ctype.h> 5 #include <linux/fd.h> 6 #include <linux/tty.h> 7 #include <linux/suspend.h> 8 #include <linux/root_dev.h> 9 #include <linux/security.h> 10 #include <linux/delay.h> 11 #include <linux/mount.h> 12 #include <linux/device.h> 13 #include <linux/init.h> 14 #include <linux/fs.h> 15 #include <linux/initrd.h> 16 #include <linux/async.h> 17 #include <linux/fs_struct.h> 18 #include <linux/slab.h> 19 #include <linux/ramfs.h> 20 #include <linux/shmem_fs.h> 21 22 #include <linux/nfs_fs.h> 23 #include <linux/nfs_fs_sb.h> 24 #include <linux/nfs_mount.h> 25 #include <linux/raid/detect.h> 26 #include <uapi/linux/mount.h> 27 28 #include "do_mounts.h" 29 30 int root_mountflags = MS_RDONLY | MS_SILENT; 31 static char __initdata saved_root_name[64]; 32 static int root_wait; 33 34 dev_t ROOT_DEV; 35 36 static int __init load_ramdisk(char *str) 37 { 38 pr_warn("ignoring the deprecated load_ramdisk= option\n"); 39 return 1; 40 } 41 __setup("load_ramdisk=", load_ramdisk); 42 43 static int __init readonly(char *str) 44 { 45 if (*str) 46 return 0; 47 root_mountflags |= MS_RDONLY; 48 return 1; 49 } 50 51 static int __init readwrite(char *str) 52 { 53 if (*str) 54 return 0; 55 root_mountflags &= ~MS_RDONLY; 56 return 1; 57 } 58 59 __setup("ro", readonly); 60 __setup("rw", readwrite); 61 62 static int __init root_dev_setup(char *line) 63 { 64 strscpy(saved_root_name, line, sizeof(saved_root_name)); 65 return 1; 66 } 67 68 __setup("root=", root_dev_setup); 69 70 static int __init rootwait_setup(char *str) 71 { 72 if (*str) 73 return 0; 74 root_wait = 1; 75 return 1; 76 } 77 78 __setup("rootwait", rootwait_setup); 79 80 static char * __initdata root_mount_data; 81 static int __init root_data_setup(char *str) 82 { 83 root_mount_data = str; 84 return 1; 85 } 86 87 static char * __initdata root_fs_names; 88 static int __init fs_names_setup(char *str) 89 { 90 root_fs_names = str; 91 return 1; 92 } 93 94 static unsigned int __initdata root_delay; 95 static int __init root_delay_setup(char *str) 96 { 97 root_delay = simple_strtoul(str, NULL, 0); 98 return 1; 99 } 100 101 __setup("rootflags=", root_data_setup); 102 __setup("rootfstype=", fs_names_setup); 103 __setup("rootdelay=", root_delay_setup); 104 105 /* This can return zero length strings. Caller should check */ 106 static int __init split_fs_names(char *page, size_t size) 107 { 108 int count = 1; 109 char *p = page; 110 111 strscpy(p, root_fs_names, size); 112 while (*p++) { 113 if (p[-1] == ',') { 114 p[-1] = '\0'; 115 count++; 116 } 117 } 118 119 return count; 120 } 121 122 static int __init do_mount_root(const char *name, const char *fs, 123 const int flags, const void *data) 124 { 125 struct super_block *s; 126 struct page *p = NULL; 127 char *data_page = NULL; 128 int ret; 129 130 if (data) { 131 /* init_mount() requires a full page as fifth argument */ 132 p = alloc_page(GFP_KERNEL); 133 if (!p) 134 return -ENOMEM; 135 data_page = page_address(p); 136 /* zero-pad. init_mount() will make sure it's terminated */ 137 strncpy(data_page, data, PAGE_SIZE); 138 } 139 140 ret = init_mount(name, "/root", fs, flags, data_page); 141 if (ret) 142 goto out; 143 144 init_chdir("/root"); 145 s = current->fs->pwd.dentry->d_sb; 146 ROOT_DEV = s->s_dev; 147 printk(KERN_INFO 148 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n", 149 s->s_type->name, 150 sb_rdonly(s) ? " readonly" : "", 151 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 152 153 out: 154 if (p) 155 put_page(p); 156 return ret; 157 } 158 159 void __init mount_root_generic(char *name, char *pretty_name, int flags) 160 { 161 struct page *page = alloc_page(GFP_KERNEL); 162 char *fs_names = page_address(page); 163 char *p; 164 char b[BDEVNAME_SIZE]; 165 int num_fs, i; 166 167 scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)", 168 MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); 169 if (root_fs_names) 170 num_fs = split_fs_names(fs_names, PAGE_SIZE); 171 else 172 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE); 173 retry: 174 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) { 175 int err; 176 177 if (!*p) 178 continue; 179 err = do_mount_root(name, p, flags, root_mount_data); 180 switch (err) { 181 case 0: 182 goto out; 183 case -EACCES: 184 case -EINVAL: 185 continue; 186 } 187 /* 188 * Allow the user to distinguish between failed sys_open 189 * and bad superblock on root device. 190 * and give them a list of the available devices 191 */ 192 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n", 193 pretty_name, b, err); 194 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); 195 196 printk_all_partitions(); 197 panic("VFS: Unable to mount root fs on %s", b); 198 } 199 if (!(flags & SB_RDONLY)) { 200 flags |= SB_RDONLY; 201 goto retry; 202 } 203 204 printk("List of all partitions:\n"); 205 printk_all_partitions(); 206 printk("No filesystem could mount root, tried: "); 207 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) 208 printk(" %s", p); 209 printk("\n"); 210 panic("VFS: Unable to mount root fs on %s", b); 211 out: 212 put_page(page); 213 } 214 215 #ifdef CONFIG_ROOT_NFS 216 217 #define NFSROOT_TIMEOUT_MIN 5 218 #define NFSROOT_TIMEOUT_MAX 30 219 #define NFSROOT_RETRY_MAX 5 220 221 static void __init mount_nfs_root(void) 222 { 223 char *root_dev, *root_data; 224 unsigned int timeout; 225 int try; 226 227 if (nfs_root_data(&root_dev, &root_data)) 228 goto fail; 229 230 /* 231 * The server or network may not be ready, so try several 232 * times. Stop after a few tries in case the client wants 233 * to fall back to other boot methods. 234 */ 235 timeout = NFSROOT_TIMEOUT_MIN; 236 for (try = 1; ; try++) { 237 if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data)) 238 return; 239 if (try > NFSROOT_RETRY_MAX) 240 break; 241 242 /* Wait, in case the server refused us immediately */ 243 ssleep(timeout); 244 timeout <<= 1; 245 if (timeout > NFSROOT_TIMEOUT_MAX) 246 timeout = NFSROOT_TIMEOUT_MAX; 247 } 248 fail: 249 pr_err("VFS: Unable to mount root fs via NFS.\n"); 250 } 251 #else 252 static inline void mount_nfs_root(void) 253 { 254 } 255 #endif /* CONFIG_ROOT_NFS */ 256 257 #ifdef CONFIG_CIFS_ROOT 258 259 extern int cifs_root_data(char **dev, char **opts); 260 261 #define CIFSROOT_TIMEOUT_MIN 5 262 #define CIFSROOT_TIMEOUT_MAX 30 263 #define CIFSROOT_RETRY_MAX 5 264 265 static void __init mount_cifs_root(void) 266 { 267 char *root_dev, *root_data; 268 unsigned int timeout; 269 int try; 270 271 if (cifs_root_data(&root_dev, &root_data)) 272 goto fail; 273 274 timeout = CIFSROOT_TIMEOUT_MIN; 275 for (try = 1; ; try++) { 276 if (!do_mount_root(root_dev, "cifs", root_mountflags, 277 root_data)) 278 return; 279 if (try > CIFSROOT_RETRY_MAX) 280 break; 281 282 ssleep(timeout); 283 timeout <<= 1; 284 if (timeout > CIFSROOT_TIMEOUT_MAX) 285 timeout = CIFSROOT_TIMEOUT_MAX; 286 } 287 fail: 288 pr_err("VFS: Unable to mount root fs via SMB.\n"); 289 } 290 #else 291 static inline void mount_cifs_root(void) 292 { 293 } 294 #endif /* CONFIG_CIFS_ROOT */ 295 296 static bool __init fs_is_nodev(char *fstype) 297 { 298 struct file_system_type *fs = get_fs_type(fstype); 299 bool ret = false; 300 301 if (fs) { 302 ret = !(fs->fs_flags & FS_REQUIRES_DEV); 303 put_filesystem(fs); 304 } 305 306 return ret; 307 } 308 309 static int __init mount_nodev_root(char *root_device_name) 310 { 311 char *fs_names, *fstype; 312 int err = -EINVAL; 313 int num_fs, i; 314 315 fs_names = (void *)__get_free_page(GFP_KERNEL); 316 if (!fs_names) 317 return -EINVAL; 318 num_fs = split_fs_names(fs_names, PAGE_SIZE); 319 320 for (i = 0, fstype = fs_names; i < num_fs; 321 i++, fstype += strlen(fstype) + 1) { 322 if (!*fstype) 323 continue; 324 if (!fs_is_nodev(fstype)) 325 continue; 326 err = do_mount_root(root_device_name, fstype, root_mountflags, 327 root_mount_data); 328 if (!err) 329 break; 330 } 331 332 free_page((unsigned long)fs_names); 333 return err; 334 } 335 336 #ifdef CONFIG_BLOCK 337 static void __init mount_block_root(char *root_device_name) 338 { 339 int err = create_dev("/dev/root", ROOT_DEV); 340 341 if (err < 0) 342 pr_emerg("Failed to create /dev/root: %d\n", err); 343 mount_root_generic("/dev/root", root_device_name, root_mountflags); 344 } 345 #else 346 static inline void mount_block_root(char *root_device_name) 347 { 348 } 349 #endif /* CONFIG_BLOCK */ 350 351 void __init mount_root(char *root_device_name) 352 { 353 switch (ROOT_DEV) { 354 case Root_NFS: 355 mount_nfs_root(); 356 break; 357 case Root_CIFS: 358 mount_cifs_root(); 359 break; 360 case Root_Generic: 361 mount_root_generic(root_device_name, root_device_name, 362 root_mountflags); 363 break; 364 case 0: 365 if (root_device_name && root_fs_names && 366 mount_nodev_root(root_device_name) == 0) 367 break; 368 fallthrough; 369 default: 370 mount_block_root(root_device_name); 371 break; 372 } 373 } 374 375 /* wait for any asynchronous scanning to complete */ 376 static void __init wait_for_root(char *root_device_name) 377 { 378 if (ROOT_DEV != 0) 379 return; 380 381 pr_info("Waiting for root device %s...\n", root_device_name); 382 383 while (!driver_probe_done() || 384 early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) 385 msleep(5); 386 async_synchronize_full(); 387 388 } 389 390 static dev_t __init parse_root_device(char *root_device_name) 391 { 392 int error; 393 dev_t dev; 394 395 if (!strncmp(root_device_name, "mtd", 3) || 396 !strncmp(root_device_name, "ubi", 3)) 397 return Root_Generic; 398 if (strcmp(root_device_name, "/dev/nfs") == 0) 399 return Root_NFS; 400 if (strcmp(root_device_name, "/dev/cifs") == 0) 401 return Root_CIFS; 402 if (strcmp(root_device_name, "/dev/ram") == 0) 403 return Root_RAM0; 404 405 error = early_lookup_bdev(root_device_name, &dev); 406 if (error) { 407 if (error == -EINVAL && root_wait) { 408 pr_err("Disabling rootwait; root= is invalid.\n"); 409 root_wait = 0; 410 } 411 return 0; 412 } 413 return dev; 414 } 415 416 /* 417 * Prepare the namespace - decide what/where to mount, load ramdisks, etc. 418 */ 419 void __init prepare_namespace(void) 420 { 421 if (root_delay) { 422 printk(KERN_INFO "Waiting %d sec before mounting root device...\n", 423 root_delay); 424 ssleep(root_delay); 425 } 426 427 /* 428 * wait for the known devices to complete their probing 429 * 430 * Note: this is a potential source of long boot delays. 431 * For example, it is not atypical to wait 5 seconds here 432 * for the touchpad of a laptop to initialize. 433 */ 434 wait_for_device_probe(); 435 436 md_run_setup(); 437 438 if (saved_root_name[0]) 439 ROOT_DEV = parse_root_device(saved_root_name); 440 441 if (initrd_load(saved_root_name)) 442 goto out; 443 444 if (root_wait) 445 wait_for_root(saved_root_name); 446 mount_root(saved_root_name); 447 out: 448 devtmpfs_mount(); 449 init_mount(".", "/", NULL, MS_MOVE, NULL); 450 init_chroot("."); 451 } 452 453 static bool is_tmpfs; 454 static int rootfs_init_fs_context(struct fs_context *fc) 455 { 456 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) 457 return shmem_init_fs_context(fc); 458 459 return ramfs_init_fs_context(fc); 460 } 461 462 struct file_system_type rootfs_fs_type = { 463 .name = "rootfs", 464 .init_fs_context = rootfs_init_fs_context, 465 .kill_sb = kill_litter_super, 466 }; 467 468 void __init init_rootfs(void) 469 { 470 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] && 471 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) 472 is_tmpfs = true; 473 } 474