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 early boot */ 130 static int have_root __initdata; 131 static int have_console __initdata; 132 133 /* Set in uml_mem_setup and modified in linux_main */ 134 long long physmem_size = 64 * 1024 * 1024; 135 EXPORT_SYMBOL(physmem_size); 136 137 static const char *usage_string = 138 "User Mode Linux v%s\n" 139 " available at http://user-mode-linux.sourceforge.net/\n\n"; 140 141 static int __init uml_version_setup(char *line, int *add) 142 { 143 /* Explicitly use printf() to show version in stdout */ 144 printf("%s\n", init_utsname()->release); 145 exit(0); 146 147 return 0; 148 } 149 150 __uml_setup("--version", uml_version_setup, 151 "--version\n" 152 " Prints the version number of the kernel.\n\n" 153 ); 154 155 static int __init uml_root_setup(char *line, int *add) 156 { 157 have_root = 1; 158 return 0; 159 } 160 161 __uml_setup("root=", uml_root_setup, 162 "root=<file containing the root fs>\n" 163 " This is actually used by the generic kernel in exactly the same\n" 164 " way as in any other kernel. If you configure a number of block\n" 165 " devices and want to boot off something other than ubd0, you \n" 166 " would use something like:\n" 167 " root=/dev/ubd5\n\n" 168 ); 169 170 static int __init no_skas_debug_setup(char *line, int *add) 171 { 172 os_warn("'debug' is not necessary to gdb UML in skas mode - run\n"); 173 os_warn("'gdb linux'\n"); 174 175 return 0; 176 } 177 178 __uml_setup("debug", no_skas_debug_setup, 179 "debug\n" 180 " this flag is not needed to run gdb on UML in skas mode\n\n" 181 ); 182 183 static int __init uml_console_setup(char *line, int *add) 184 { 185 have_console = 1; 186 return 0; 187 } 188 189 __uml_setup("console=", uml_console_setup, 190 "console=<preferred console>\n" 191 " Specify the preferred console output driver\n\n" 192 ); 193 194 static int __init Usage(char *line, int *add) 195 { 196 const char **p; 197 198 printf(usage_string, init_utsname()->release); 199 p = &__uml_help_start; 200 /* Explicitly use printf() to show help in stdout */ 201 while (p < &__uml_help_end) { 202 printf("%s", *p); 203 p++; 204 } 205 exit(0); 206 return 0; 207 } 208 209 __uml_setup("--help", Usage, 210 "--help\n" 211 " Prints this message.\n\n" 212 ); 213 214 static void __init uml_checksetup(char *line, int *add) 215 { 216 struct uml_param *p; 217 218 p = &__uml_setup_start; 219 while (p < &__uml_setup_end) { 220 size_t n; 221 222 n = strlen(p->str); 223 if (!strncmp(line, p->str, n) && p->setup_func(line + n, add)) 224 return; 225 p++; 226 } 227 } 228 229 static void __init uml_postsetup(void) 230 { 231 initcall_t *p; 232 233 p = &__uml_postsetup_start; 234 while (p < &__uml_postsetup_end) { 235 (*p)(); 236 p++; 237 } 238 return; 239 } 240 241 static int panic_exit(struct notifier_block *self, unsigned long unused1, 242 void *unused2) 243 { 244 kmsg_dump(KMSG_DUMP_PANIC); 245 bust_spinlocks(1); 246 bust_spinlocks(0); 247 uml_exitcode = 1; 248 os_dump_core(); 249 250 return NOTIFY_DONE; 251 } 252 253 static struct notifier_block panic_exit_notifier = { 254 .notifier_call = panic_exit, 255 .priority = INT_MAX - 1, /* run as 2nd notifier, won't return */ 256 }; 257 258 void uml_finishsetup(void) 259 { 260 atomic_notifier_chain_register(&panic_notifier_list, 261 &panic_exit_notifier); 262 263 uml_postsetup(); 264 265 new_thread_handler(); 266 } 267 268 /* Set during early boot */ 269 unsigned long stub_start; 270 unsigned long task_size; 271 EXPORT_SYMBOL(task_size); 272 273 unsigned long host_task_size; 274 275 unsigned long brk_start; 276 unsigned long end_iomem; 277 EXPORT_SYMBOL(end_iomem); 278 279 #define MIN_VMALLOC (32 * 1024 * 1024) 280 281 static void parse_host_cpu_flags(char *line) 282 { 283 int i; 284 for (i = 0; i < 32*NCAPINTS; i++) { 285 if ((x86_cap_flags[i] != NULL) && strstr(line, x86_cap_flags[i])) 286 set_cpu_cap(&boot_cpu_data, i); 287 } 288 } 289 static void parse_cache_line(char *line) 290 { 291 long res; 292 char *to_parse = strstr(line, ":"); 293 if (to_parse) { 294 to_parse++; 295 while (*to_parse != 0 && isspace(*to_parse)) { 296 to_parse++; 297 } 298 if (kstrtoul(to_parse, 10, &res) == 0 && is_power_of_2(res)) 299 boot_cpu_data.cache_alignment = res; 300 else 301 boot_cpu_data.cache_alignment = L1_CACHE_BYTES; 302 } 303 } 304 305 int __init linux_main(int argc, char **argv) 306 { 307 unsigned long avail, diff; 308 unsigned long virtmem_size, max_physmem; 309 unsigned long stack; 310 unsigned int i; 311 int add; 312 313 for (i = 1; i < argc; i++) { 314 if ((i == 1) && (argv[i][0] == ' ')) 315 continue; 316 add = 1; 317 uml_checksetup(argv[i], &add); 318 if (add) 319 add_arg(argv[i]); 320 } 321 if (have_root == 0) 322 add_arg(DEFAULT_COMMAND_LINE_ROOT); 323 324 if (have_console == 0) 325 add_arg(DEFAULT_COMMAND_LINE_CONSOLE); 326 327 host_task_size = os_get_top_address(); 328 /* reserve a few pages for the stubs (taking care of data alignment) */ 329 /* align the data portion */ 330 BUILD_BUG_ON(!is_power_of_2(STUB_DATA_PAGES)); 331 stub_start = (host_task_size - 1) & ~(STUB_DATA_PAGES * PAGE_SIZE - 1); 332 /* another page for the code portion */ 333 stub_start -= PAGE_SIZE; 334 host_task_size = stub_start; 335 336 /* 337 * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps 338 * out 339 */ 340 task_size = host_task_size & PGDIR_MASK; 341 342 /* OS sanity checks that need to happen before the kernel runs */ 343 os_early_checks(); 344 345 get_host_cpu_features(parse_host_cpu_flags, parse_cache_line); 346 347 brk_start = (unsigned long) sbrk(0); 348 349 /* 350 * Increase physical memory size for exec-shield users 351 * so they actually get what they asked for. This should 352 * add zero for non-exec shield users 353 */ 354 355 diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end); 356 if (diff > 1024 * 1024) { 357 os_info("Adding %ld bytes to physical memory to account for " 358 "exec-shield gap\n", diff); 359 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end); 360 } 361 362 uml_physmem = (unsigned long) __binary_start & PAGE_MASK; 363 364 /* Reserve up to 4M after the current brk */ 365 uml_reserved = ROUND_4M(brk_start) + (1 << 22); 366 367 setup_machinename(init_utsname()->machine); 368 369 highmem = 0; 370 iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK; 371 max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC; 372 373 /* 374 * Zones have to begin on a 1 << MAX_PAGE_ORDER page boundary, 375 * so this makes sure that's true for highmem 376 */ 377 max_physmem &= ~((1 << (PAGE_SHIFT + MAX_PAGE_ORDER)) - 1); 378 if (physmem_size + iomem_size > max_physmem) { 379 highmem = physmem_size + iomem_size - max_physmem; 380 physmem_size -= highmem; 381 } 382 383 high_physmem = uml_physmem + physmem_size; 384 end_iomem = high_physmem + iomem_size; 385 high_memory = (void *) end_iomem; 386 387 start_vm = VMALLOC_START; 388 389 virtmem_size = physmem_size; 390 stack = (unsigned long) argv; 391 stack &= ~(1024 * 1024 - 1); 392 avail = stack - start_vm; 393 if (physmem_size > avail) 394 virtmem_size = avail; 395 end_vm = start_vm + virtmem_size; 396 397 if (virtmem_size < physmem_size) 398 os_info("Kernel virtual memory size shrunk to %lu bytes\n", 399 virtmem_size); 400 401 os_flush_stdout(); 402 403 return start_uml(); 404 } 405 406 int __init __weak read_initrd(void) 407 { 408 return 0; 409 } 410 411 void __init setup_arch(char **cmdline_p) 412 { 413 u8 rng_seed[32]; 414 415 stack_protections((unsigned long) &init_thread_info); 416 setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem); 417 mem_total_pages(physmem_size, iomem_size, highmem); 418 uml_dtb_init(); 419 read_initrd(); 420 421 paging_init(); 422 strscpy(boot_command_line, command_line, COMMAND_LINE_SIZE); 423 *cmdline_p = command_line; 424 setup_hostinfo(host_info, sizeof host_info); 425 426 if (os_getrandom(rng_seed, sizeof(rng_seed), 0) == sizeof(rng_seed)) { 427 add_bootloader_randomness(rng_seed, sizeof(rng_seed)); 428 memzero_explicit(rng_seed, sizeof(rng_seed)); 429 } 430 } 431 432 void __init arch_cpu_finalize_init(void) 433 { 434 arch_check_bugs(); 435 os_check_bugs(); 436 } 437 438 void apply_seal_endbr(s32 *start, s32 *end) 439 { 440 } 441 442 void apply_retpolines(s32 *start, s32 *end) 443 { 444 } 445 446 void apply_returns(s32 *start, s32 *end) 447 { 448 } 449 450 void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline, 451 s32 *start_cfi, s32 *end_cfi) 452 { 453 } 454 455 void apply_alternatives(struct alt_instr *start, struct alt_instr *end) 456 { 457 } 458 459 void *text_poke(void *addr, const void *opcode, size_t len) 460 { 461 /* 462 * In UML, the only reference to this function is in 463 * apply_relocate_add(), which shouldn't ever actually call this 464 * because UML doesn't have live patching. 465 */ 466 WARN_ON(1); 467 468 return memcpy(addr, opcode, len); 469 } 470 471 void text_poke_sync(void) 472 { 473 } 474 475 void uml_pm_wake(void) 476 { 477 pm_system_wakeup(); 478 } 479 480 #ifdef CONFIG_PM_SLEEP 481 static int um_suspend_valid(suspend_state_t state) 482 { 483 return state == PM_SUSPEND_MEM; 484 } 485 486 static int um_suspend_prepare(void) 487 { 488 um_irqs_suspend(); 489 return 0; 490 } 491 492 static int um_suspend_enter(suspend_state_t state) 493 { 494 if (WARN_ON(state != PM_SUSPEND_MEM)) 495 return -EINVAL; 496 497 /* 498 * This is identical to the idle sleep, but we've just 499 * (during suspend) turned off all interrupt sources 500 * except for the ones we want, so now we can only wake 501 * up on something we actually want to wake up on. All 502 * timing has also been suspended. 503 */ 504 um_idle_sleep(); 505 return 0; 506 } 507 508 static void um_suspend_finish(void) 509 { 510 um_irqs_resume(); 511 } 512 513 const struct platform_suspend_ops um_suspend_ops = { 514 .valid = um_suspend_valid, 515 .prepare = um_suspend_prepare, 516 .enter = um_suspend_enter, 517 .finish = um_suspend_finish, 518 }; 519 520 static int init_pm_wake_signal(void) 521 { 522 /* 523 * In external time-travel mode we can't use signals to wake up 524 * since that would mess with the scheduling. We'll have to do 525 * some additional work to support wakeup on virtio devices or 526 * similar, perhaps implementing a fake RTC controller that can 527 * trigger wakeup (and request the appropriate scheduling from 528 * the external scheduler when going to suspend.) 529 */ 530 if (time_travel_mode != TT_MODE_EXTERNAL) 531 register_pm_wake_signal(); 532 533 suspend_set_ops(&um_suspend_ops); 534 535 return 0; 536 } 537 538 late_initcall(init_pm_wake_signal); 539 #endif 540