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/delay.h> 7 #include <linux/init.h> 8 #include <linux/mm.h> 9 #include <linux/module.h> 10 #include <linux/seq_file.h> 11 #include <linux/string.h> 12 #include <linux/utsname.h> 13 #include <linux/sched.h> 14 #include <linux/sched/task.h> 15 #include <linux/kmsg_dump.h> 16 17 #include <asm/processor.h> 18 #include <asm/sections.h> 19 #include <asm/setup.h> 20 #include <as-layout.h> 21 #include <arch.h> 22 #include <init.h> 23 #include <kern.h> 24 #include <kern_util.h> 25 #include <mem_user.h> 26 #include <os.h> 27 28 #define DEFAULT_COMMAND_LINE "root=98:0" 29 30 /* Changed in add_arg and setup_arch, which run before SMP is started */ 31 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 }; 32 33 static void __init add_arg(char *arg) 34 { 35 if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) { 36 os_warn("add_arg: Too many command line arguments!\n"); 37 exit(1); 38 } 39 if (strlen(command_line) > 0) 40 strcat(command_line, " "); 41 strcat(command_line, arg); 42 } 43 44 /* 45 * These fields are initialized at boot time and not changed. 46 * XXX This structure is used only in the non-SMP case. Maybe this 47 * should be moved to smp.c. 48 */ 49 struct cpuinfo_um boot_cpu_data = { 50 .loops_per_jiffy = 0, 51 .ipi_pipe = { -1, -1 } 52 }; 53 54 union thread_union cpu0_irqstack 55 __attribute__((__section__(".data..init_irqstack"))) = 56 { .thread_info = INIT_THREAD_INFO(init_task) }; 57 58 /* Changed in setup_arch, which is called in early boot */ 59 static char host_info[(__NEW_UTS_LEN + 1) * 5]; 60 61 static int show_cpuinfo(struct seq_file *m, void *v) 62 { 63 int index = 0; 64 65 seq_printf(m, "processor\t: %d\n", index); 66 seq_printf(m, "vendor_id\t: User Mode Linux\n"); 67 seq_printf(m, "model name\t: UML\n"); 68 seq_printf(m, "mode\t\t: skas\n"); 69 seq_printf(m, "host\t\t: %s\n", host_info); 70 seq_printf(m, "bogomips\t: %lu.%02lu\n\n", 71 loops_per_jiffy/(500000/HZ), 72 (loops_per_jiffy/(5000/HZ)) % 100); 73 74 return 0; 75 } 76 77 static void *c_start(struct seq_file *m, loff_t *pos) 78 { 79 return *pos < NR_CPUS ? cpu_data + *pos : NULL; 80 } 81 82 static void *c_next(struct seq_file *m, void *v, loff_t *pos) 83 { 84 ++*pos; 85 return c_start(m, pos); 86 } 87 88 static void c_stop(struct seq_file *m, void *v) 89 { 90 } 91 92 const struct seq_operations cpuinfo_op = { 93 .start = c_start, 94 .next = c_next, 95 .stop = c_stop, 96 .show = show_cpuinfo, 97 }; 98 99 /* Set in linux_main */ 100 unsigned long uml_physmem; 101 EXPORT_SYMBOL(uml_physmem); 102 103 unsigned long uml_reserved; /* Also modified in mem_init */ 104 unsigned long start_vm; 105 unsigned long end_vm; 106 107 /* Set in uml_ncpus_setup */ 108 int ncpus = 1; 109 110 /* Set in early boot */ 111 static int have_root __initdata = 0; 112 113 /* Set in uml_mem_setup and modified in linux_main */ 114 long long physmem_size = 32 * 1024 * 1024; 115 EXPORT_SYMBOL(physmem_size); 116 117 static const char *usage_string = 118 "User Mode Linux v%s\n" 119 " available at http://user-mode-linux.sourceforge.net/\n\n"; 120 121 static int __init uml_version_setup(char *line, int *add) 122 { 123 /* Explicitly use printf() to show version in stdout */ 124 printf("%s\n", init_utsname()->release); 125 exit(0); 126 127 return 0; 128 } 129 130 __uml_setup("--version", uml_version_setup, 131 "--version\n" 132 " Prints the version number of the kernel.\n\n" 133 ); 134 135 static int __init uml_root_setup(char *line, int *add) 136 { 137 have_root = 1; 138 return 0; 139 } 140 141 __uml_setup("root=", uml_root_setup, 142 "root=<file containing the root fs>\n" 143 " This is actually used by the generic kernel in exactly the same\n" 144 " way as in any other kernel. If you configure a number of block\n" 145 " devices and want to boot off something other than ubd0, you \n" 146 " would use something like:\n" 147 " root=/dev/ubd5\n\n" 148 ); 149 150 static int __init no_skas_debug_setup(char *line, int *add) 151 { 152 os_warn("'debug' is not necessary to gdb UML in skas mode - run\n"); 153 os_warn("'gdb linux'\n"); 154 155 return 0; 156 } 157 158 __uml_setup("debug", no_skas_debug_setup, 159 "debug\n" 160 " this flag is not needed to run gdb on UML in skas mode\n\n" 161 ); 162 163 static int __init Usage(char *line, int *add) 164 { 165 const char **p; 166 167 printf(usage_string, init_utsname()->release); 168 p = &__uml_help_start; 169 /* Explicitly use printf() to show help in stdout */ 170 while (p < &__uml_help_end) { 171 printf("%s", *p); 172 p++; 173 } 174 exit(0); 175 return 0; 176 } 177 178 __uml_setup("--help", Usage, 179 "--help\n" 180 " Prints this message.\n\n" 181 ); 182 183 static void __init uml_checksetup(char *line, int *add) 184 { 185 struct uml_param *p; 186 187 p = &__uml_setup_start; 188 while (p < &__uml_setup_end) { 189 size_t n; 190 191 n = strlen(p->str); 192 if (!strncmp(line, p->str, n) && p->setup_func(line + n, add)) 193 return; 194 p++; 195 } 196 } 197 198 static void __init uml_postsetup(void) 199 { 200 initcall_t *p; 201 202 p = &__uml_postsetup_start; 203 while (p < &__uml_postsetup_end) { 204 (*p)(); 205 p++; 206 } 207 return; 208 } 209 210 static int panic_exit(struct notifier_block *self, unsigned long unused1, 211 void *unused2) 212 { 213 kmsg_dump(KMSG_DUMP_PANIC); 214 bust_spinlocks(1); 215 bust_spinlocks(0); 216 uml_exitcode = 1; 217 os_dump_core(); 218 return 0; 219 } 220 221 static struct notifier_block panic_exit_notifier = { 222 .notifier_call = panic_exit, 223 .next = NULL, 224 .priority = 0 225 }; 226 227 void uml_finishsetup(void) 228 { 229 atomic_notifier_chain_register(&panic_notifier_list, 230 &panic_exit_notifier); 231 232 uml_postsetup(); 233 234 new_thread_handler(); 235 } 236 237 /* Set during early boot */ 238 unsigned long task_size; 239 EXPORT_SYMBOL(task_size); 240 241 unsigned long host_task_size; 242 243 unsigned long brk_start; 244 unsigned long end_iomem; 245 EXPORT_SYMBOL(end_iomem); 246 247 #define MIN_VMALLOC (32 * 1024 * 1024) 248 249 int __init linux_main(int argc, char **argv) 250 { 251 unsigned long avail, diff; 252 unsigned long virtmem_size, max_physmem; 253 unsigned long stack; 254 unsigned int i; 255 int add; 256 257 for (i = 1; i < argc; i++) { 258 if ((i == 1) && (argv[i][0] == ' ')) 259 continue; 260 add = 1; 261 uml_checksetup(argv[i], &add); 262 if (add) 263 add_arg(argv[i]); 264 } 265 if (have_root == 0) 266 add_arg(DEFAULT_COMMAND_LINE); 267 268 host_task_size = os_get_top_address(); 269 /* 270 * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps 271 * out 272 */ 273 task_size = host_task_size & PGDIR_MASK; 274 275 /* OS sanity checks that need to happen before the kernel runs */ 276 os_early_checks(); 277 278 brk_start = (unsigned long) sbrk(0); 279 280 /* 281 * Increase physical memory size for exec-shield users 282 * so they actually get what they asked for. This should 283 * add zero for non-exec shield users 284 */ 285 286 diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end); 287 if (diff > 1024 * 1024) { 288 os_info("Adding %ld bytes to physical memory to account for " 289 "exec-shield gap\n", diff); 290 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end); 291 } 292 293 uml_physmem = (unsigned long) __binary_start & PAGE_MASK; 294 295 /* Reserve up to 4M after the current brk */ 296 uml_reserved = ROUND_4M(brk_start) + (1 << 22); 297 298 setup_machinename(init_utsname()->machine); 299 300 highmem = 0; 301 iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK; 302 max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC; 303 304 /* 305 * Zones have to begin on a 1 << MAX_ORDER page boundary, 306 * so this makes sure that's true for highmem 307 */ 308 max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1); 309 if (physmem_size + iomem_size > max_physmem) { 310 highmem = physmem_size + iomem_size - max_physmem; 311 physmem_size -= highmem; 312 } 313 314 high_physmem = uml_physmem + physmem_size; 315 end_iomem = high_physmem + iomem_size; 316 high_memory = (void *) end_iomem; 317 318 start_vm = VMALLOC_START; 319 320 virtmem_size = physmem_size; 321 stack = (unsigned long) argv; 322 stack &= ~(1024 * 1024 - 1); 323 avail = stack - start_vm; 324 if (physmem_size > avail) 325 virtmem_size = avail; 326 end_vm = start_vm + virtmem_size; 327 328 if (virtmem_size < physmem_size) 329 os_info("Kernel virtual memory size shrunk to %lu bytes\n", 330 virtmem_size); 331 332 os_flush_stdout(); 333 334 return start_uml(); 335 } 336 337 int __init __weak read_initrd(void) 338 { 339 return 0; 340 } 341 342 void __init setup_arch(char **cmdline_p) 343 { 344 stack_protections((unsigned long) &init_thread_info); 345 setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem); 346 mem_total_pages(physmem_size, iomem_size, highmem); 347 read_initrd(); 348 349 paging_init(); 350 strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE); 351 *cmdline_p = command_line; 352 setup_hostinfo(host_info, sizeof host_info); 353 } 354 355 void __init check_bugs(void) 356 { 357 arch_check_bugs(); 358 os_check_bugs(); 359 } 360 361 void apply_alternatives(struct alt_instr *start, struct alt_instr *end) 362 { 363 } 364 365 void *text_poke(void *addr, const void *opcode, size_t len) 366 { 367 /* 368 * In UML, the only reference to this function is in 369 * apply_relocate_add(), which shouldn't ever actually call this 370 * because UML doesn't have live patching. 371 */ 372 WARN_ON(1); 373 374 return memcpy(addr, opcode, len); 375 } 376 377 void text_poke_sync(void) 378 { 379 } 380