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 69 /* Changed in setup_arch, which is called in early boot */ 70 static char host_info[(__NEW_UTS_LEN + 1) * 5]; 71 72 static int show_cpuinfo(struct seq_file *m, void *v) 73 { 74 int i = 0; 75 76 seq_printf(m, "processor\t: %d\n", i); 77 seq_printf(m, "vendor_id\t: User Mode Linux\n"); 78 seq_printf(m, "model name\t: UML\n"); 79 seq_printf(m, "mode\t\t: skas\n"); 80 seq_printf(m, "host\t\t: %s\n", host_info); 81 seq_printf(m, "fpu\t\t: %s\n", cpu_has(&boot_cpu_data, X86_FEATURE_FPU) ? "yes" : "no"); 82 seq_printf(m, "flags\t\t:"); 83 for (i = 0; i < 32*NCAPINTS; i++) 84 if (cpu_has(&boot_cpu_data, i) && (x86_cap_flags[i] != NULL)) 85 seq_printf(m, " %s", x86_cap_flags[i]); 86 seq_printf(m, "\n"); 87 seq_printf(m, "cache_alignment\t: %d\n", boot_cpu_data.cache_alignment); 88 seq_printf(m, "bogomips\t: %lu.%02lu\n", 89 loops_per_jiffy/(500000/HZ), 90 (loops_per_jiffy/(5000/HZ)) % 100); 91 92 93 return 0; 94 } 95 96 static void *c_start(struct seq_file *m, loff_t *pos) 97 { 98 return *pos < nr_cpu_ids ? &boot_cpu_data + *pos : NULL; 99 } 100 101 static void *c_next(struct seq_file *m, void *v, loff_t *pos) 102 { 103 ++*pos; 104 return c_start(m, pos); 105 } 106 107 static void c_stop(struct seq_file *m, void *v) 108 { 109 } 110 111 const struct seq_operations cpuinfo_op = { 112 .start = c_start, 113 .next = c_next, 114 .stop = c_stop, 115 .show = show_cpuinfo, 116 }; 117 118 /* Set in linux_main */ 119 unsigned long uml_physmem; 120 EXPORT_SYMBOL(uml_physmem); 121 122 unsigned long uml_reserved; /* Also modified in mem_init */ 123 unsigned long start_vm; 124 unsigned long end_vm; 125 126 /* Set in early boot */ 127 static int have_root __initdata; 128 static int have_console __initdata; 129 130 /* Set in uml_mem_setup and modified in linux_main */ 131 unsigned long long physmem_size = 64 * 1024 * 1024; 132 EXPORT_SYMBOL(physmem_size); 133 134 static const char *usage_string = 135 "User Mode Linux v%s\n" 136 " available at http://user-mode-linux.sourceforge.net/\n\n"; 137 138 static int __init uml_version_setup(char *line, int *add) 139 { 140 /* Explicitly use printf() to show version in stdout */ 141 printf("%s\n", init_utsname()->release); 142 exit(0); 143 144 return 0; 145 } 146 147 __uml_setup("--version", uml_version_setup, 148 "--version\n" 149 " Prints the version number of the kernel.\n\n" 150 ); 151 152 static int __init uml_root_setup(char *line, int *add) 153 { 154 have_root = 1; 155 return 0; 156 } 157 158 __uml_setup("root=", uml_root_setup, 159 "root=<file containing the root fs>\n" 160 " This is actually used by the generic kernel in exactly the same\n" 161 " way as in any other kernel. If you configure a number of block\n" 162 " devices and want to boot off something other than ubd0, you \n" 163 " would use something like:\n" 164 " root=/dev/ubd5\n\n" 165 ); 166 167 static int __init uml_console_setup(char *line, int *add) 168 { 169 have_console = 1; 170 return 0; 171 } 172 173 __uml_setup("console=", uml_console_setup, 174 "console=<preferred console>\n" 175 " Specify the preferred console output driver\n\n" 176 ); 177 178 static int __init Usage(char *line, int *add) 179 { 180 const char **p; 181 182 printf(usage_string, init_utsname()->release); 183 p = &__uml_help_start; 184 /* Explicitly use printf() to show help in stdout */ 185 while (p < &__uml_help_end) { 186 printf("%s", *p); 187 p++; 188 } 189 exit(0); 190 return 0; 191 } 192 193 __uml_setup("--help", Usage, 194 "--help\n" 195 " Prints this message.\n\n" 196 ); 197 198 static void __init uml_checksetup(char *line, int *add) 199 { 200 struct uml_param *p; 201 202 p = &__uml_setup_start; 203 while (p < &__uml_setup_end) { 204 size_t n; 205 206 n = strlen(p->str); 207 if (!strncmp(line, p->str, n) && p->setup_func(line + n, add)) 208 return; 209 p++; 210 } 211 } 212 213 static void __init uml_postsetup(void) 214 { 215 initcall_t *p; 216 217 p = &__uml_postsetup_start; 218 while (p < &__uml_postsetup_end) { 219 (*p)(); 220 p++; 221 } 222 return; 223 } 224 225 static int panic_exit(struct notifier_block *self, unsigned long unused1, 226 void *unused2) 227 { 228 kmsg_dump(KMSG_DUMP_PANIC); 229 bust_spinlocks(1); 230 bust_spinlocks(0); 231 uml_exitcode = 1; 232 os_dump_core(); 233 234 return NOTIFY_DONE; 235 } 236 237 static struct notifier_block panic_exit_notifier = { 238 .notifier_call = panic_exit, 239 .priority = INT_MAX - 1, /* run as 2nd notifier, won't return */ 240 }; 241 242 void uml_finishsetup(void) 243 { 244 cpu_tasks[0] = &init_task; 245 246 atomic_notifier_chain_register(&panic_notifier_list, 247 &panic_exit_notifier); 248 249 uml_postsetup(); 250 251 new_thread_handler(); 252 } 253 254 /* Set during early boot */ 255 unsigned long stub_start; 256 unsigned long task_size; 257 EXPORT_SYMBOL(task_size); 258 259 unsigned long host_task_size; 260 261 unsigned long brk_start; 262 unsigned long end_iomem; 263 EXPORT_SYMBOL(end_iomem); 264 265 #define MIN_VMALLOC (32 * 1024 * 1024) 266 267 static void parse_host_cpu_flags(char *line) 268 { 269 int i; 270 for (i = 0; i < 32*NCAPINTS; i++) { 271 if ((x86_cap_flags[i] != NULL) && strstr(line, x86_cap_flags[i])) 272 set_cpu_cap(&boot_cpu_data, i); 273 } 274 } 275 static void parse_cache_line(char *line) 276 { 277 long res; 278 char *to_parse = strstr(line, ":"); 279 if (to_parse) { 280 to_parse++; 281 while (*to_parse != 0 && isspace(*to_parse)) { 282 to_parse++; 283 } 284 if (kstrtoul(to_parse, 10, &res) == 0 && is_power_of_2(res)) 285 boot_cpu_data.cache_alignment = res; 286 else 287 boot_cpu_data.cache_alignment = L1_CACHE_BYTES; 288 } 289 } 290 291 static unsigned long get_top_address(char **envp) 292 { 293 unsigned long top_addr = (unsigned long) &top_addr; 294 int i; 295 296 /* The earliest variable should be after the program name in ELF */ 297 for (i = 0; envp[i]; i++) { 298 if ((unsigned long) envp[i] > top_addr) 299 top_addr = (unsigned long) envp[i]; 300 } 301 302 top_addr &= ~(UM_KERN_PAGE_SIZE - 1); 303 top_addr += UM_KERN_PAGE_SIZE; 304 305 return top_addr; 306 } 307 308 int __init linux_main(int argc, char **argv, char **envp) 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 = get_top_address(envp); 331 /* reserve a few pages for the stubs */ 332 stub_start = host_task_size - STUB_DATA_PAGES * PAGE_SIZE; 333 /* another page for the code portion */ 334 stub_start -= PAGE_SIZE; 335 host_task_size = stub_start; 336 337 /* Limit TASK_SIZE to what is addressable by the page table */ 338 task_size = host_task_size; 339 if (task_size > (unsigned long long) PTRS_PER_PGD * PGDIR_SIZE) 340 task_size = PTRS_PER_PGD * PGDIR_SIZE; 341 342 /* 343 * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps 344 * out 345 */ 346 task_size = task_size & PGDIR_MASK; 347 348 /* OS sanity checks that need to happen before the kernel runs */ 349 os_early_checks(); 350 351 get_host_cpu_features(parse_host_cpu_flags, parse_cache_line); 352 353 brk_start = (unsigned long) sbrk(0); 354 355 /* 356 * Increase physical memory size for exec-shield users 357 * so they actually get what they asked for. This should 358 * add zero for non-exec shield users 359 */ 360 361 diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end); 362 if (diff > 1024 * 1024) { 363 os_info("Adding %ld bytes to physical memory to account for " 364 "exec-shield gap\n", diff); 365 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end); 366 } 367 368 uml_physmem = (unsigned long) __binary_start & PAGE_MASK; 369 370 /* Reserve up to 4M after the current brk */ 371 uml_reserved = ROUND_4M(brk_start) + (1 << 22); 372 373 setup_machinename(init_utsname()->machine); 374 375 physmem_size = (physmem_size + PAGE_SIZE - 1) & PAGE_MASK; 376 iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK; 377 378 max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC; 379 380 if (physmem_size + iomem_size > max_physmem) { 381 physmem_size = max_physmem - iomem_size; 382 os_info("Physical memory size shrunk to %llu bytes\n", 383 physmem_size); 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 arch_task_struct_size = sizeof(struct task_struct) + host_fp_size; 405 406 os_flush_stdout(); 407 408 return start_uml(); 409 } 410 411 int __init __weak read_initrd(void) 412 { 413 return 0; 414 } 415 416 void __init setup_arch(char **cmdline_p) 417 { 418 u8 rng_seed[32]; 419 420 stack_protections((unsigned long) init_task.stack); 421 setup_physmem(uml_physmem, uml_reserved, physmem_size); 422 mem_total_pages(physmem_size, iomem_size); 423 uml_dtb_init(); 424 read_initrd(); 425 426 paging_init(); 427 strscpy(boot_command_line, command_line, COMMAND_LINE_SIZE); 428 *cmdline_p = command_line; 429 setup_hostinfo(host_info, sizeof host_info); 430 431 if (os_getrandom(rng_seed, sizeof(rng_seed), 0) == sizeof(rng_seed)) { 432 add_bootloader_randomness(rng_seed, sizeof(rng_seed)); 433 memzero_explicit(rng_seed, sizeof(rng_seed)); 434 } 435 } 436 437 void __init arch_cpu_finalize_init(void) 438 { 439 arch_check_bugs(); 440 os_check_bugs(); 441 } 442 443 void apply_seal_endbr(s32 *start, s32 *end, struct module *mod) 444 { 445 } 446 447 void apply_retpolines(s32 *start, s32 *end, struct module *mod) 448 { 449 } 450 451 void apply_returns(s32 *start, s32 *end, struct module *mod) 452 { 453 } 454 455 void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline, 456 s32 *start_cfi, s32 *end_cfi, struct module *mod) 457 { 458 } 459 460 void apply_alternatives(struct alt_instr *start, struct alt_instr *end, 461 struct module *mod) 462 { 463 } 464 465 void *text_poke(void *addr, const void *opcode, size_t len) 466 { 467 /* 468 * In UML, the only reference to this function is in 469 * apply_relocate_add(), which shouldn't ever actually call this 470 * because UML doesn't have live patching. 471 */ 472 WARN_ON(1); 473 474 return memcpy(addr, opcode, len); 475 } 476 477 void *text_poke_copy(void *addr, const void *opcode, size_t len) 478 { 479 return text_poke(addr, opcode, len); 480 } 481 482 void text_poke_sync(void) 483 { 484 } 485 486 void uml_pm_wake(void) 487 { 488 pm_system_wakeup(); 489 } 490 491 #ifdef CONFIG_PM_SLEEP 492 static int um_suspend_valid(suspend_state_t state) 493 { 494 return state == PM_SUSPEND_MEM; 495 } 496 497 static int um_suspend_prepare(void) 498 { 499 um_irqs_suspend(); 500 return 0; 501 } 502 503 static int um_suspend_enter(suspend_state_t state) 504 { 505 if (WARN_ON(state != PM_SUSPEND_MEM)) 506 return -EINVAL; 507 508 /* 509 * This is identical to the idle sleep, but we've just 510 * (during suspend) turned off all interrupt sources 511 * except for the ones we want, so now we can only wake 512 * up on something we actually want to wake up on. All 513 * timing has also been suspended. 514 */ 515 um_idle_sleep(); 516 return 0; 517 } 518 519 static void um_suspend_finish(void) 520 { 521 um_irqs_resume(); 522 } 523 524 const struct platform_suspend_ops um_suspend_ops = { 525 .valid = um_suspend_valid, 526 .prepare = um_suspend_prepare, 527 .enter = um_suspend_enter, 528 .finish = um_suspend_finish, 529 }; 530 531 static int init_pm_wake_signal(void) 532 { 533 /* 534 * In external time-travel mode we can't use signals to wake up 535 * since that would mess with the scheduling. We'll have to do 536 * some additional work to support wakeup on virtio devices or 537 * similar, perhaps implementing a fake RTC controller that can 538 * trigger wakeup (and request the appropriate scheduling from 539 * the external scheduler when going to suspend.) 540 */ 541 if (time_travel_mode != TT_MODE_EXTERNAL) 542 register_pm_wake_signal(); 543 544 suspend_set_ops(&um_suspend_ops); 545 546 return 0; 547 } 548 549 late_initcall(init_pm_wake_signal); 550 #endif 551