1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 4 */ 5 6 #include <linux/cpu.h> 7 #include <linux/delay.h> 8 #include <linux/init.h> 9 #include <linux/mm.h> 10 #include <linux/ctype.h> 11 #include <linux/module.h> 12 #include <linux/panic_notifier.h> 13 #include <linux/seq_file.h> 14 #include <linux/string.h> 15 #include <linux/utsname.h> 16 #include <linux/sched.h> 17 #include <linux/sched/task.h> 18 #include <linux/kmsg_dump.h> 19 #include <linux/suspend.h> 20 #include <linux/random.h> 21 22 #include <asm/processor.h> 23 #include <asm/cpufeature.h> 24 #include <asm/sections.h> 25 #include <asm/setup.h> 26 #include <asm/text-patching.h> 27 #include <as-layout.h> 28 #include <arch.h> 29 #include <init.h> 30 #include <kern.h> 31 #include <kern_util.h> 32 #include <mem_user.h> 33 #include <os.h> 34 35 #include "um_arch.h" 36 37 #define DEFAULT_COMMAND_LINE_ROOT "root=98:0" 38 #define DEFAULT_COMMAND_LINE_CONSOLE "console=tty0" 39 40 /* Changed in add_arg and setup_arch, which run before SMP is started */ 41 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 }; 42 43 static void __init add_arg(char *arg) 44 { 45 if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) { 46 os_warn("add_arg: Too many command line arguments!\n"); 47 exit(1); 48 } 49 if (strlen(command_line) > 0) 50 strcat(command_line, " "); 51 strcat(command_line, arg); 52 } 53 54 /* 55 * These fields are initialized at boot time and not changed. 56 * XXX This structure is used only in the non-SMP case. Maybe this 57 * should be moved to smp.c. 58 */ 59 struct cpuinfo_um boot_cpu_data = { 60 .loops_per_jiffy = 0, 61 .ipi_pipe = { -1, -1 }, 62 .cache_alignment = L1_CACHE_BYTES, 63 .x86_capability = { 0 } 64 }; 65 66 EXPORT_SYMBOL(boot_cpu_data); 67 68 union thread_union cpu0_irqstack 69 __section(".data..init_irqstack") = 70 { .thread_info = INIT_THREAD_INFO(init_task) }; 71 72 /* Changed in setup_arch, which is called in early boot */ 73 static char host_info[(__NEW_UTS_LEN + 1) * 5]; 74 75 static int show_cpuinfo(struct seq_file *m, void *v) 76 { 77 int i = 0; 78 79 seq_printf(m, "processor\t: %d\n", i); 80 seq_printf(m, "vendor_id\t: User Mode Linux\n"); 81 seq_printf(m, "model name\t: UML\n"); 82 seq_printf(m, "mode\t\t: skas\n"); 83 seq_printf(m, "host\t\t: %s\n", host_info); 84 seq_printf(m, "fpu\t\t: %s\n", cpu_has(&boot_cpu_data, X86_FEATURE_FPU) ? "yes" : "no"); 85 seq_printf(m, "flags\t\t:"); 86 for (i = 0; i < 32*NCAPINTS; i++) 87 if (cpu_has(&boot_cpu_data, i) && (x86_cap_flags[i] != NULL)) 88 seq_printf(m, " %s", x86_cap_flags[i]); 89 seq_printf(m, "\n"); 90 seq_printf(m, "cache_alignment\t: %d\n", boot_cpu_data.cache_alignment); 91 seq_printf(m, "bogomips\t: %lu.%02lu\n", 92 loops_per_jiffy/(500000/HZ), 93 (loops_per_jiffy/(5000/HZ)) % 100); 94 95 96 return 0; 97 } 98 99 static void *c_start(struct seq_file *m, loff_t *pos) 100 { 101 return *pos < nr_cpu_ids ? &boot_cpu_data + *pos : NULL; 102 } 103 104 static void *c_next(struct seq_file *m, void *v, loff_t *pos) 105 { 106 ++*pos; 107 return c_start(m, pos); 108 } 109 110 static void c_stop(struct seq_file *m, void *v) 111 { 112 } 113 114 const struct seq_operations cpuinfo_op = { 115 .start = c_start, 116 .next = c_next, 117 .stop = c_stop, 118 .show = show_cpuinfo, 119 }; 120 121 /* Set in linux_main */ 122 unsigned long uml_physmem; 123 EXPORT_SYMBOL(uml_physmem); 124 125 unsigned long uml_reserved; /* Also modified in mem_init */ 126 unsigned long start_vm; 127 unsigned long end_vm; 128 129 /* Set in uml_ncpus_setup */ 130 int ncpus = 1; 131 132 /* Set in early boot */ 133 static int have_root __initdata; 134 static int have_console __initdata; 135 136 /* Set in uml_mem_setup and modified in linux_main */ 137 long long physmem_size = 64 * 1024 * 1024; 138 EXPORT_SYMBOL(physmem_size); 139 140 static const char *usage_string = 141 "User Mode Linux v%s\n" 142 " available at http://user-mode-linux.sourceforge.net/\n\n"; 143 144 static int __init uml_version_setup(char *line, int *add) 145 { 146 /* Explicitly use printf() to show version in stdout */ 147 printf("%s\n", init_utsname()->release); 148 exit(0); 149 150 return 0; 151 } 152 153 __uml_setup("--version", uml_version_setup, 154 "--version\n" 155 " Prints the version number of the kernel.\n\n" 156 ); 157 158 static int __init uml_root_setup(char *line, int *add) 159 { 160 have_root = 1; 161 return 0; 162 } 163 164 __uml_setup("root=", uml_root_setup, 165 "root=<file containing the root fs>\n" 166 " This is actually used by the generic kernel in exactly the same\n" 167 " way as in any other kernel. If you configure a number of block\n" 168 " devices and want to boot off something other than ubd0, you \n" 169 " would use something like:\n" 170 " root=/dev/ubd5\n\n" 171 ); 172 173 static int __init no_skas_debug_setup(char *line, int *add) 174 { 175 os_warn("'debug' is not necessary to gdb UML in skas mode - run\n"); 176 os_warn("'gdb linux'\n"); 177 178 return 0; 179 } 180 181 __uml_setup("debug", no_skas_debug_setup, 182 "debug\n" 183 " this flag is not needed to run gdb on UML in skas mode\n\n" 184 ); 185 186 static int __init uml_console_setup(char *line, int *add) 187 { 188 have_console = 1; 189 return 0; 190 } 191 192 __uml_setup("console=", uml_console_setup, 193 "console=<preferred console>\n" 194 " Specify the preferred console output driver\n\n" 195 ); 196 197 static int __init Usage(char *line, int *add) 198 { 199 const char **p; 200 201 printf(usage_string, init_utsname()->release); 202 p = &__uml_help_start; 203 /* Explicitly use printf() to show help in stdout */ 204 while (p < &__uml_help_end) { 205 printf("%s", *p); 206 p++; 207 } 208 exit(0); 209 return 0; 210 } 211 212 __uml_setup("--help", Usage, 213 "--help\n" 214 " Prints this message.\n\n" 215 ); 216 217 static void __init uml_checksetup(char *line, int *add) 218 { 219 struct uml_param *p; 220 221 p = &__uml_setup_start; 222 while (p < &__uml_setup_end) { 223 size_t n; 224 225 n = strlen(p->str); 226 if (!strncmp(line, p->str, n) && p->setup_func(line + n, add)) 227 return; 228 p++; 229 } 230 } 231 232 static void __init uml_postsetup(void) 233 { 234 initcall_t *p; 235 236 p = &__uml_postsetup_start; 237 while (p < &__uml_postsetup_end) { 238 (*p)(); 239 p++; 240 } 241 return; 242 } 243 244 static int panic_exit(struct notifier_block *self, unsigned long unused1, 245 void *unused2) 246 { 247 kmsg_dump(KMSG_DUMP_PANIC); 248 bust_spinlocks(1); 249 bust_spinlocks(0); 250 uml_exitcode = 1; 251 os_dump_core(); 252 253 return NOTIFY_DONE; 254 } 255 256 static struct notifier_block panic_exit_notifier = { 257 .notifier_call = panic_exit, 258 .priority = INT_MAX - 1, /* run as 2nd notifier, won't return */ 259 }; 260 261 void uml_finishsetup(void) 262 { 263 atomic_notifier_chain_register(&panic_notifier_list, 264 &panic_exit_notifier); 265 266 uml_postsetup(); 267 268 new_thread_handler(); 269 } 270 271 /* Set during early boot */ 272 unsigned long stub_start; 273 unsigned long task_size; 274 EXPORT_SYMBOL(task_size); 275 276 unsigned long host_task_size; 277 278 unsigned long brk_start; 279 unsigned long end_iomem; 280 EXPORT_SYMBOL(end_iomem); 281 282 #define MIN_VMALLOC (32 * 1024 * 1024) 283 284 static void parse_host_cpu_flags(char *line) 285 { 286 int i; 287 for (i = 0; i < 32*NCAPINTS; i++) { 288 if ((x86_cap_flags[i] != NULL) && strstr(line, x86_cap_flags[i])) 289 set_cpu_cap(&boot_cpu_data, i); 290 } 291 } 292 static void parse_cache_line(char *line) 293 { 294 long res; 295 char *to_parse = strstr(line, ":"); 296 if (to_parse) { 297 to_parse++; 298 while (*to_parse != 0 && isspace(*to_parse)) { 299 to_parse++; 300 } 301 if (kstrtoul(to_parse, 10, &res) == 0 && is_power_of_2(res)) 302 boot_cpu_data.cache_alignment = res; 303 else 304 boot_cpu_data.cache_alignment = L1_CACHE_BYTES; 305 } 306 } 307 308 int __init linux_main(int argc, char **argv) 309 { 310 unsigned long avail, diff; 311 unsigned long virtmem_size, max_physmem; 312 unsigned long stack; 313 unsigned int i; 314 int add; 315 316 for (i = 1; i < argc; i++) { 317 if ((i == 1) && (argv[i][0] == ' ')) 318 continue; 319 add = 1; 320 uml_checksetup(argv[i], &add); 321 if (add) 322 add_arg(argv[i]); 323 } 324 if (have_root == 0) 325 add_arg(DEFAULT_COMMAND_LINE_ROOT); 326 327 if (have_console == 0) 328 add_arg(DEFAULT_COMMAND_LINE_CONSOLE); 329 330 host_task_size = os_get_top_address(); 331 /* reserve a few pages for the stubs (taking care of data alignment) */ 332 /* align the data portion */ 333 BUILD_BUG_ON(!is_power_of_2(STUB_DATA_PAGES)); 334 stub_start = (host_task_size - 1) & ~(STUB_DATA_PAGES * PAGE_SIZE - 1); 335 /* another page for the code portion */ 336 stub_start -= PAGE_SIZE; 337 host_task_size = stub_start; 338 339 /* 340 * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps 341 * out 342 */ 343 task_size = host_task_size & PGDIR_MASK; 344 345 /* OS sanity checks that need to happen before the kernel runs */ 346 os_early_checks(); 347 348 get_host_cpu_features(parse_host_cpu_flags, parse_cache_line); 349 350 brk_start = (unsigned long) sbrk(0); 351 352 /* 353 * Increase physical memory size for exec-shield users 354 * so they actually get what they asked for. This should 355 * add zero for non-exec shield users 356 */ 357 358 diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end); 359 if (diff > 1024 * 1024) { 360 os_info("Adding %ld bytes to physical memory to account for " 361 "exec-shield gap\n", diff); 362 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end); 363 } 364 365 uml_physmem = (unsigned long) __binary_start & PAGE_MASK; 366 367 /* Reserve up to 4M after the current brk */ 368 uml_reserved = ROUND_4M(brk_start) + (1 << 22); 369 370 setup_machinename(init_utsname()->machine); 371 372 highmem = 0; 373 iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK; 374 max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC; 375 376 /* 377 * Zones have to begin on a 1 << MAX_PAGE_ORDER page boundary, 378 * so this makes sure that's true for highmem 379 */ 380 max_physmem &= ~((1 << (PAGE_SHIFT + MAX_PAGE_ORDER)) - 1); 381 if (physmem_size + iomem_size > max_physmem) { 382 highmem = physmem_size + iomem_size - max_physmem; 383 physmem_size -= highmem; 384 } 385 386 high_physmem = uml_physmem + physmem_size; 387 end_iomem = high_physmem + iomem_size; 388 high_memory = (void *) end_iomem; 389 390 start_vm = VMALLOC_START; 391 392 virtmem_size = physmem_size; 393 stack = (unsigned long) argv; 394 stack &= ~(1024 * 1024 - 1); 395 avail = stack - start_vm; 396 if (physmem_size > avail) 397 virtmem_size = avail; 398 end_vm = start_vm + virtmem_size; 399 400 if (virtmem_size < physmem_size) 401 os_info("Kernel virtual memory size shrunk to %lu bytes\n", 402 virtmem_size); 403 404 os_flush_stdout(); 405 406 return start_uml(); 407 } 408 409 int __init __weak read_initrd(void) 410 { 411 return 0; 412 } 413 414 void __init setup_arch(char **cmdline_p) 415 { 416 u8 rng_seed[32]; 417 418 stack_protections((unsigned long) &init_thread_info); 419 setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem); 420 mem_total_pages(physmem_size, iomem_size, highmem); 421 uml_dtb_init(); 422 read_initrd(); 423 424 paging_init(); 425 strscpy(boot_command_line, command_line, COMMAND_LINE_SIZE); 426 *cmdline_p = command_line; 427 setup_hostinfo(host_info, sizeof host_info); 428 429 if (os_getrandom(rng_seed, sizeof(rng_seed), 0) == sizeof(rng_seed)) { 430 add_bootloader_randomness(rng_seed, sizeof(rng_seed)); 431 memzero_explicit(rng_seed, sizeof(rng_seed)); 432 } 433 } 434 435 void __init arch_cpu_finalize_init(void) 436 { 437 arch_check_bugs(); 438 os_check_bugs(); 439 } 440 441 void apply_seal_endbr(s32 *start, s32 *end) 442 { 443 } 444 445 void apply_retpolines(s32 *start, s32 *end) 446 { 447 } 448 449 void apply_returns(s32 *start, s32 *end) 450 { 451 } 452 453 void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline, 454 s32 *start_cfi, s32 *end_cfi) 455 { 456 } 457 458 void apply_alternatives(struct alt_instr *start, struct alt_instr *end) 459 { 460 } 461 462 void *text_poke(void *addr, const void *opcode, size_t len) 463 { 464 /* 465 * In UML, the only reference to this function is in 466 * apply_relocate_add(), which shouldn't ever actually call this 467 * because UML doesn't have live patching. 468 */ 469 WARN_ON(1); 470 471 return memcpy(addr, opcode, len); 472 } 473 474 void text_poke_sync(void) 475 { 476 } 477 478 void uml_pm_wake(void) 479 { 480 pm_system_wakeup(); 481 } 482 483 #ifdef CONFIG_PM_SLEEP 484 static int um_suspend_valid(suspend_state_t state) 485 { 486 return state == PM_SUSPEND_MEM; 487 } 488 489 static int um_suspend_prepare(void) 490 { 491 um_irqs_suspend(); 492 return 0; 493 } 494 495 static int um_suspend_enter(suspend_state_t state) 496 { 497 if (WARN_ON(state != PM_SUSPEND_MEM)) 498 return -EINVAL; 499 500 /* 501 * This is identical to the idle sleep, but we've just 502 * (during suspend) turned off all interrupt sources 503 * except for the ones we want, so now we can only wake 504 * up on something we actually want to wake up on. All 505 * timing has also been suspended. 506 */ 507 um_idle_sleep(); 508 return 0; 509 } 510 511 static void um_suspend_finish(void) 512 { 513 um_irqs_resume(); 514 } 515 516 const struct platform_suspend_ops um_suspend_ops = { 517 .valid = um_suspend_valid, 518 .prepare = um_suspend_prepare, 519 .enter = um_suspend_enter, 520 .finish = um_suspend_finish, 521 }; 522 523 static int init_pm_wake_signal(void) 524 { 525 /* 526 * In external time-travel mode we can't use signals to wake up 527 * since that would mess with the scheduling. We'll have to do 528 * some additional work to support wakeup on virtio devices or 529 * similar, perhaps implementing a fake RTC controller that can 530 * trigger wakeup (and request the appropriate scheduling from 531 * the external scheduler when going to suspend.) 532 */ 533 if (time_travel_mode != TT_MODE_EXTERNAL) 534 register_pm_wake_signal(); 535 536 suspend_set_ops(&um_suspend_ops); 537 538 return 0; 539 } 540 541 late_initcall(init_pm_wake_signal); 542 #endif 543