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 unsigned 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 uml_console_setup(char *line, int *add) 171 { 172 have_console = 1; 173 return 0; 174 } 175 176 __uml_setup("console=", uml_console_setup, 177 "console=<preferred console>\n" 178 " Specify the preferred console output driver\n\n" 179 ); 180 181 static int __init Usage(char *line, int *add) 182 { 183 const char **p; 184 185 printf(usage_string, init_utsname()->release); 186 p = &__uml_help_start; 187 /* Explicitly use printf() to show help in stdout */ 188 while (p < &__uml_help_end) { 189 printf("%s", *p); 190 p++; 191 } 192 exit(0); 193 return 0; 194 } 195 196 __uml_setup("--help", Usage, 197 "--help\n" 198 " Prints this message.\n\n" 199 ); 200 201 static void __init uml_checksetup(char *line, int *add) 202 { 203 struct uml_param *p; 204 205 p = &__uml_setup_start; 206 while (p < &__uml_setup_end) { 207 size_t n; 208 209 n = strlen(p->str); 210 if (!strncmp(line, p->str, n) && p->setup_func(line + n, add)) 211 return; 212 p++; 213 } 214 } 215 216 static void __init uml_postsetup(void) 217 { 218 initcall_t *p; 219 220 p = &__uml_postsetup_start; 221 while (p < &__uml_postsetup_end) { 222 (*p)(); 223 p++; 224 } 225 return; 226 } 227 228 static int panic_exit(struct notifier_block *self, unsigned long unused1, 229 void *unused2) 230 { 231 kmsg_dump(KMSG_DUMP_PANIC); 232 bust_spinlocks(1); 233 bust_spinlocks(0); 234 uml_exitcode = 1; 235 os_dump_core(); 236 237 return NOTIFY_DONE; 238 } 239 240 static struct notifier_block panic_exit_notifier = { 241 .notifier_call = panic_exit, 242 .priority = INT_MAX - 1, /* run as 2nd notifier, won't return */ 243 }; 244 245 void uml_finishsetup(void) 246 { 247 atomic_notifier_chain_register(&panic_notifier_list, 248 &panic_exit_notifier); 249 250 uml_postsetup(); 251 252 new_thread_handler(); 253 } 254 255 /* Set during early boot */ 256 unsigned long stub_start; 257 unsigned long task_size; 258 EXPORT_SYMBOL(task_size); 259 260 unsigned long host_task_size; 261 262 unsigned long brk_start; 263 unsigned long end_iomem; 264 EXPORT_SYMBOL(end_iomem); 265 266 #define MIN_VMALLOC (32 * 1024 * 1024) 267 268 static void parse_host_cpu_flags(char *line) 269 { 270 int i; 271 for (i = 0; i < 32*NCAPINTS; i++) { 272 if ((x86_cap_flags[i] != NULL) && strstr(line, x86_cap_flags[i])) 273 set_cpu_cap(&boot_cpu_data, i); 274 } 275 } 276 static void parse_cache_line(char *line) 277 { 278 long res; 279 char *to_parse = strstr(line, ":"); 280 if (to_parse) { 281 to_parse++; 282 while (*to_parse != 0 && isspace(*to_parse)) { 283 to_parse++; 284 } 285 if (kstrtoul(to_parse, 10, &res) == 0 && is_power_of_2(res)) 286 boot_cpu_data.cache_alignment = res; 287 else 288 boot_cpu_data.cache_alignment = L1_CACHE_BYTES; 289 } 290 } 291 292 static unsigned long get_top_address(char **envp) 293 { 294 unsigned long top_addr = (unsigned long) &top_addr; 295 int i; 296 297 /* The earliest variable should be after the program name in ELF */ 298 for (i = 0; envp[i]; i++) { 299 if ((unsigned long) envp[i] > top_addr) 300 top_addr = (unsigned long) envp[i]; 301 } 302 303 top_addr &= ~(UM_KERN_PAGE_SIZE - 1); 304 top_addr += UM_KERN_PAGE_SIZE; 305 306 return top_addr; 307 } 308 309 int __init linux_main(int argc, char **argv, char **envp) 310 { 311 unsigned long avail, diff; 312 unsigned long virtmem_size, max_physmem; 313 unsigned long stack; 314 unsigned int i; 315 int add; 316 317 for (i = 1; i < argc; i++) { 318 if ((i == 1) && (argv[i][0] == ' ')) 319 continue; 320 add = 1; 321 uml_checksetup(argv[i], &add); 322 if (add) 323 add_arg(argv[i]); 324 } 325 if (have_root == 0) 326 add_arg(DEFAULT_COMMAND_LINE_ROOT); 327 328 if (have_console == 0) 329 add_arg(DEFAULT_COMMAND_LINE_CONSOLE); 330 331 host_task_size = get_top_address(envp); 332 /* reserve a few pages for the stubs */ 333 stub_start = host_task_size - STUB_DATA_PAGES * PAGE_SIZE; 334 /* another page for the code portion */ 335 stub_start -= PAGE_SIZE; 336 host_task_size = stub_start; 337 338 /* Limit TASK_SIZE to what is addressable by the page table */ 339 task_size = host_task_size; 340 if (task_size > (unsigned long long) PTRS_PER_PGD * PGDIR_SIZE) 341 task_size = PTRS_PER_PGD * PGDIR_SIZE; 342 343 /* 344 * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps 345 * out 346 */ 347 task_size = task_size & PGDIR_MASK; 348 349 /* OS sanity checks that need to happen before the kernel runs */ 350 os_early_checks(); 351 352 get_host_cpu_features(parse_host_cpu_flags, parse_cache_line); 353 354 brk_start = (unsigned long) sbrk(0); 355 356 /* 357 * Increase physical memory size for exec-shield users 358 * so they actually get what they asked for. This should 359 * add zero for non-exec shield users 360 */ 361 362 diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end); 363 if (diff > 1024 * 1024) { 364 os_info("Adding %ld bytes to physical memory to account for " 365 "exec-shield gap\n", diff); 366 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end); 367 } 368 369 uml_physmem = (unsigned long) __binary_start & PAGE_MASK; 370 371 /* Reserve up to 4M after the current brk */ 372 uml_reserved = ROUND_4M(brk_start) + (1 << 22); 373 374 setup_machinename(init_utsname()->machine); 375 376 physmem_size = (physmem_size + PAGE_SIZE - 1) & PAGE_MASK; 377 iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK; 378 379 max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC; 380 381 if (physmem_size + iomem_size > max_physmem) { 382 physmem_size = max_physmem - iomem_size; 383 os_info("Physical memory size shrunk to %llu bytes\n", 384 physmem_size); 385 } 386 387 high_physmem = uml_physmem + physmem_size; 388 end_iomem = high_physmem + iomem_size; 389 high_memory = (void *) end_iomem; 390 391 start_vm = VMALLOC_START; 392 393 virtmem_size = physmem_size; 394 stack = (unsigned long) argv; 395 stack &= ~(1024 * 1024 - 1); 396 avail = stack - start_vm; 397 if (physmem_size > avail) 398 virtmem_size = avail; 399 end_vm = start_vm + virtmem_size; 400 401 if (virtmem_size < physmem_size) 402 os_info("Kernel virtual memory size shrunk to %lu bytes\n", 403 virtmem_size); 404 405 os_flush_stdout(); 406 407 return start_uml(); 408 } 409 410 int __init __weak read_initrd(void) 411 { 412 return 0; 413 } 414 415 void __init setup_arch(char **cmdline_p) 416 { 417 u8 rng_seed[32]; 418 419 stack_protections((unsigned long) &init_thread_info); 420 setup_physmem(uml_physmem, uml_reserved, physmem_size); 421 mem_total_pages(physmem_size, iomem_size); 422 uml_dtb_init(); 423 read_initrd(); 424 425 paging_init(); 426 strscpy(boot_command_line, command_line, COMMAND_LINE_SIZE); 427 *cmdline_p = command_line; 428 setup_hostinfo(host_info, sizeof host_info); 429 430 if (os_getrandom(rng_seed, sizeof(rng_seed), 0) == sizeof(rng_seed)) { 431 add_bootloader_randomness(rng_seed, sizeof(rng_seed)); 432 memzero_explicit(rng_seed, sizeof(rng_seed)); 433 } 434 } 435 436 void __init arch_cpu_finalize_init(void) 437 { 438 arch_check_bugs(); 439 os_check_bugs(); 440 } 441 442 void apply_seal_endbr(s32 *start, s32 *end) 443 { 444 } 445 446 void apply_retpolines(s32 *start, s32 *end) 447 { 448 } 449 450 void apply_returns(s32 *start, s32 *end) 451 { 452 } 453 454 void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline, 455 s32 *start_cfi, s32 *end_cfi) 456 { 457 } 458 459 void apply_alternatives(struct alt_instr *start, struct alt_instr *end) 460 { 461 } 462 463 void *text_poke(void *addr, const void *opcode, size_t len) 464 { 465 /* 466 * In UML, the only reference to this function is in 467 * apply_relocate_add(), which shouldn't ever actually call this 468 * because UML doesn't have live patching. 469 */ 470 WARN_ON(1); 471 472 return memcpy(addr, opcode, len); 473 } 474 475 void text_poke_sync(void) 476 { 477 } 478 479 void uml_pm_wake(void) 480 { 481 pm_system_wakeup(); 482 } 483 484 #ifdef CONFIG_PM_SLEEP 485 static int um_suspend_valid(suspend_state_t state) 486 { 487 return state == PM_SUSPEND_MEM; 488 } 489 490 static int um_suspend_prepare(void) 491 { 492 um_irqs_suspend(); 493 return 0; 494 } 495 496 static int um_suspend_enter(suspend_state_t state) 497 { 498 if (WARN_ON(state != PM_SUSPEND_MEM)) 499 return -EINVAL; 500 501 /* 502 * This is identical to the idle sleep, but we've just 503 * (during suspend) turned off all interrupt sources 504 * except for the ones we want, so now we can only wake 505 * up on something we actually want to wake up on. All 506 * timing has also been suspended. 507 */ 508 um_idle_sleep(); 509 return 0; 510 } 511 512 static void um_suspend_finish(void) 513 { 514 um_irqs_resume(); 515 } 516 517 const struct platform_suspend_ops um_suspend_ops = { 518 .valid = um_suspend_valid, 519 .prepare = um_suspend_prepare, 520 .enter = um_suspend_enter, 521 .finish = um_suspend_finish, 522 }; 523 524 static int init_pm_wake_signal(void) 525 { 526 /* 527 * In external time-travel mode we can't use signals to wake up 528 * since that would mess with the scheduling. We'll have to do 529 * some additional work to support wakeup on virtio devices or 530 * similar, perhaps implementing a fake RTC controller that can 531 * trigger wakeup (and request the appropriate scheduling from 532 * the external scheduler when going to suspend.) 533 */ 534 if (time_travel_mode != TT_MODE_EXTERNAL) 535 register_pm_wake_signal(); 536 537 suspend_set_ops(&um_suspend_ops); 538 539 return 0; 540 } 541 542 late_initcall(init_pm_wake_signal); 543 #endif 544