arch/um/kernel/um_arch.c

   1 /*
   2  * Copyright (C) 2000, 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/kernel.h"
   7 #include "linux/sched.h"
   8 #include "linux/notifier.h"
   9 #include "linux/mm.h"
  10 #include "linux/types.h"
  11 #include "linux/tty.h"
  12 #include "linux/init.h"
  13 #include "linux/bootmem.h"
  14 #include "linux/spinlock.h"
  15 #include "linux/utsname.h"
  16 #include "linux/sysrq.h"
  17 #include "linux/seq_file.h"
  18 #include "linux/delay.h"
  19 #include "linux/module.h"
  20 #include "linux/utsname.h"
  21 #include "asm/page.h"
  22 #include "asm/pgtable.h"
  23 #include "asm/ptrace.h"
  24 #include "asm/elf.h"
  25 #include "asm/user.h"
  26 #include "asm/setup.h"
  27 #include "ubd_user.h"
  28 #include "asm/current.h"
  29 #include "kern_util.h"
  30 #include "as-layout.h"
  31 #include "arch.h"
  32 #include "kern.h"
  33 #include "mem_user.h"
  34 #include "mem.h"
  35 #include "initrd.h"
  36 #include "init.h"
  37 #include "os.h"
  38 #include "choose-mode.h"
  39 #include "mode_kern.h"
  40 #include "mode.h"
  41 #ifdef UML_CONFIG_MODE_SKAS
  42 #include "skas.h"
  43 #endif
  44
  45 #define DEFAULT_COMMAND_LINE "root=98:0"
  46
  47 /* Changed in linux_main and setup_arch, which run before SMP is started */
  48 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
  49
  50 static void __init add_arg(char *arg)
  51 {
  52         if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
  53                 printf("add_arg: Too many command line arguments!\n");
  54                 exit(1);
  55         }
  56         if(strlen(command_line) > 0)
  57                 strcat(command_line, " ");
  58         strcat(command_line, arg);
  59 }
  60
  61 struct cpuinfo_um boot_cpu_data = {
  62         .loops_per_jiffy        = 0,
  63         .ipi_pipe               = { -1, -1 }
  64 };
  65
  66 unsigned long thread_saved_pc(struct task_struct *task)
  67 {
  68         return os_process_pc(CHOOSE_MODE_PROC(thread_pid_tt, thread_pid_skas,
  69                                               task));
  70 }
  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 index = 0;
  78
  79 #ifdef CONFIG_SMP
  80         index = (struct cpuinfo_um *) v - cpu_data;
  81         if (!cpu_online(index))
  82                 return 0;
  83 #endif
  84
  85         seq_printf(m, "processor\t: %d\n", index);
  86         seq_printf(m, "vendor_id\t: User Mode Linux\n");
  87         seq_printf(m, "model name\t: UML\n");
  88         seq_printf(m, "mode\t\t: %s\n", CHOOSE_MODE("tt", "skas"));
  89         seq_printf(m, "host\t\t: %s\n", host_info);
  90         seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
  91                    loops_per_jiffy/(500000/HZ),
  92                    (loops_per_jiffy/(5000/HZ)) % 100);
  93
  94         return 0;
  95 }
  96
  97 static void *c_start(struct seq_file *m, loff_t *pos)
  98 {
  99         return *pos < NR_CPUS ? cpu_data + *pos : NULL;
 100 }
 101
 102 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 103 {
 104         ++*pos;
 105         return c_start(m, pos);
 106 }
 107
 108 static void c_stop(struct seq_file *m, void *v)
 109 {
 110 }
 111
 112 const struct seq_operations cpuinfo_op = {
 113         .start  = c_start,
 114         .next   = c_next,
 115         .stop   = c_stop,
 116         .show   = show_cpuinfo,
 117 };
 118
 119 /* Set in linux_main */
 120 unsigned long host_task_size;
 121 unsigned long task_size;
 122
 123 unsigned long uml_start;
 124
 125 /* Set in early boot */
 126 unsigned long uml_physmem;
 127 unsigned long uml_reserved;
 128 unsigned long start_vm;
 129 unsigned long end_vm;
 130 int ncpus = 1;
 131
 132 #ifdef CONFIG_CMDLINE_ON_HOST
 133 /* Pointer set in linux_main, the array itself is private to each thread,
 134  * and changed at address space creation time so this poses no concurrency
 135  * problems.
 136  */
 137 static char *argv1_begin = NULL;
 138 static char *argv1_end = NULL;
 139 #endif
 140
 141 /* Set in early boot */
 142 static int have_root __initdata = 0;
 143 long long physmem_size = 32 * 1024 * 1024;
 144
 145 void set_cmdline(char *cmd)
 146 {
 147 #ifdef CONFIG_CMDLINE_ON_HOST
 148         char *umid, *ptr;
 149
 150         if(CHOOSE_MODE(honeypot, 0)) return;
 151
 152         umid = get_umid();
 153         if(*umid != '\0'){
 154                 snprintf(argv1_begin,
 155                          (argv1_end - argv1_begin) * sizeof(*ptr),
 156                          "(%s) ", umid);
 157                 ptr = &argv1_begin[strlen(argv1_begin)];
 158         }
 159         else ptr = argv1_begin;
 160
 161         snprintf(ptr, (argv1_end - ptr) * sizeof(*ptr), "[%s]", cmd);
 162         memset(argv1_begin + strlen(argv1_begin), '\0',
 163                argv1_end - argv1_begin - strlen(argv1_begin));
 164 #endif
 165 }
 166
 167 static char *usage_string =
 168 "User Mode Linux v%s\n"
 169 "       available at http://user-mode-linux.sourceforge.net/\n\n";
 170
 171 static int __init uml_version_setup(char *line, int *add)
 172 {
 173         printf("%s\n", init_utsname()->release);
 174         exit(0);
 175
 176         return 0;
 177 }
 178
 179 __uml_setup("--version", uml_version_setup,
 180 "--version\n"
 181 "    Prints the version number of the kernel.\n\n"
 182 );
 183
 184 static int __init uml_root_setup(char *line, int *add)
 185 {
 186         have_root = 1;
 187         return 0;
 188 }
 189
 190 __uml_setup("root=", uml_root_setup,
 191 "root=<file containing the root fs>\n"
 192 "    This is actually used by the generic kernel in exactly the same\n"
 193 "    way as in any other kernel. If you configure a number of block\n"
 194 "    devices and want to boot off something other than ubd0, you \n"
 195 "    would use something like:\n"
 196 "        root=/dev/ubd5\n\n"
 197 );
 198
 199 #ifndef CONFIG_MODE_TT
 200
 201 static int __init no_skas_debug_setup(char *line, int *add)
 202 {
 203         printf("'debug' is not necessary to gdb UML in skas mode - run \n");
 204         printf("'gdb linux' and disable CONFIG_CMDLINE_ON_HOST if gdb \n");
 205         printf("doesn't work as expected\n");
 206
 207         return 0;
 208 }
 209
 210 __uml_setup("debug", no_skas_debug_setup,
 211 "debug\n"
 212 "    this flag is not needed to run gdb on UML in skas mode\n\n"
 213 );
 214
 215 #endif
 216
 217 #ifdef CONFIG_SMP
 218 static int __init uml_ncpus_setup(char *line, int *add)
 219 {
 220         if (!sscanf(line, "%d", &ncpus)) {
 221                 printf("Couldn't parse [%s]\n", line);
 222                 return -1;
 223         }
 224
 225         return 0;
 226 }
 227
 228 __uml_setup("ncpus=", uml_ncpus_setup,
 229 "ncpus=<# of desired CPUs>\n"
 230 "    This tells an SMP kernel how many virtual processors to start.\n\n"
 231 );
 232 #endif
 233
 234 static int force_tt = 0;
 235
 236 #if defined(CONFIG_MODE_TT) && defined(CONFIG_MODE_SKAS)
 237 #define DEFAULT_TT 0
 238
 239 static int __init mode_tt_setup(char *line, int *add)
 240 {
 241         force_tt = 1;
 242         return 0;
 243 }
 244
 245 #else
 246 #ifdef CONFIG_MODE_SKAS
 247
 248 #define DEFAULT_TT 0
 249
 250 static int __init mode_tt_setup(char *line, int *add)
 251 {
 252         printf("CONFIG_MODE_TT disabled - 'mode=tt' ignored\n");
 253         return 0;
 254 }
 255
 256 #else
 257 #ifdef CONFIG_MODE_TT
 258
 259 #define DEFAULT_TT 1
 260
 261 static int __init mode_tt_setup(char *line, int *add)
 262 {
 263         printf("CONFIG_MODE_SKAS disabled - 'mode=tt' redundant\n");
 264         return 0;
 265 }
 266
 267 #endif
 268 #endif
 269 #endif
 270
 271 __uml_setup("mode=tt", mode_tt_setup,
 272 "mode=tt\n"
 273 "    When both CONFIG_MODE_TT and CONFIG_MODE_SKAS are enabled, this option\n"
 274 "    forces UML to run in tt (tracing thread) mode.  It is not the default\n"
 275 "    because it's slower and less secure than skas mode.\n\n"
 276 );
 277
 278 int mode_tt = DEFAULT_TT;
 279
 280 static int __init Usage(char *line, int *add)
 281 {
 282         const char **p;
 283
 284         printf(usage_string, init_utsname()->release);
 285         p = &__uml_help_start;
 286         while (p < &__uml_help_end) {
 287                 printf("%s", *p);
 288                 p++;
 289         }
 290         exit(0);
 291         return 0;
 292 }
 293
 294 __uml_setup("--help", Usage,
 295 "--help\n"
 296 "    Prints this message.\n\n"
 297 );
 298
 299 static int __init uml_checksetup(char *line, int *add)
 300 {
 301         struct uml_param *p;
 302
 303         p = &__uml_setup_start;
 304         while(p < &__uml_setup_end) {
 305                 int n;
 306
 307                 n = strlen(p->str);
 308                 if(!strncmp(line, p->str, n)){
 309                         if (p->setup_func(line + n, add)) return 1;
 310                 }
 311                 p++;
 312         }
 313         return 0;
 314 }
 315
 316 static void __init uml_postsetup(void)
 317 {
 318         initcall_t *p;
 319
 320         p = &__uml_postsetup_start;
 321         while(p < &__uml_postsetup_end){
 322                 (*p)();
 323                 p++;
 324         }
 325         return;
 326 }
 327
 328 /* Set during early boot */
 329 unsigned long brk_start;
 330 unsigned long end_iomem;
 331 EXPORT_SYMBOL(end_iomem);
 332
 333 #define MIN_VMALLOC (32 * 1024 * 1024)
 334
 335 extern char __binary_start;
 336
 337 int __init linux_main(int argc, char **argv)
 338 {
 339         unsigned long avail, diff;
 340         unsigned long virtmem_size, max_physmem;
 341         unsigned int i, add;
 342         char * mode;
 343
 344         for (i = 1; i < argc; i++){
 345                 if((i == 1) && (argv[i][0] == ' ')) continue;
 346                 add = 1;
 347                 uml_checksetup(argv[i], &add);
 348                 if (add)
 349                         add_arg(argv[i]);
 350         }
 351         if(have_root == 0)
 352                 add_arg(DEFAULT_COMMAND_LINE);
 353
 354         os_early_checks();
 355         if (force_tt)
 356                 clear_can_do_skas();
 357         mode_tt = force_tt ? 1 : !can_do_skas();
 358 #ifndef CONFIG_MODE_TT
 359         if (mode_tt) {
 360                 /*Since CONFIG_MODE_TT is #undef'ed, force_tt cannot be 1. So,
 361                  * can_do_skas() returned 0, and the message is correct. */
 362                 printf("Support for TT mode is disabled, and no SKAS support is present on the host.\n");
 363                 exit(1);
 364         }
 365 #endif
 366
 367 #ifndef CONFIG_MODE_SKAS
 368         mode = "TT";
 369 #else
 370         /* Show to the user the result of selection */
 371         if (mode_tt)
 372                 mode = "TT";
 373         else if (proc_mm && ptrace_faultinfo)
 374                 mode = "SKAS3";
 375         else
 376                 mode = "SKAS0";
 377 #endif
 378
 379         printf("UML running in %s mode\n", mode);
 380
 381         uml_start = (unsigned long) &__binary_start;
 382         host_task_size = CHOOSE_MODE_PROC(set_task_sizes_tt,
 383                                           set_task_sizes_skas, &task_size);
 384
 385         /*
 386          * Setting up handlers to 'sig_info' struct
 387          */
 388         os_fill_handlinfo(handlinfo_kern);
 389
 390         brk_start = (unsigned long) sbrk(0);
 391         CHOOSE_MODE_PROC(before_mem_tt, before_mem_skas, brk_start);
 392         /* Increase physical memory size for exec-shield users
 393         so they actually get what they asked for. This should
 394         add zero for non-exec shield users */
 395
 396         diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 397         if(diff > 1024 * 1024){
 398                 printf("Adding %ld bytes to physical memory to account for "
 399                        "exec-shield gap\n", diff);
 400                 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 401         }
 402
 403         uml_physmem = uml_start & PAGE_MASK;
 404
 405         /* Reserve up to 4M after the current brk */
 406         uml_reserved = ROUND_4M(brk_start) + (1 << 22);
 407
 408         setup_machinename(init_utsname()->machine);
 409
 410 #ifdef CONFIG_CMDLINE_ON_HOST
 411         argv1_begin = argv[1];
 412         argv1_end = &argv[1][strlen(argv[1])];
 413 #endif
 414
 415         highmem = 0;
 416         iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
 417         max_physmem = get_kmem_end() - uml_physmem - iomem_size - MIN_VMALLOC;
 418
 419         /* Zones have to begin on a 1 << MAX_ORDER page boundary,
 420          * so this makes sure that's true for highmem
 421          */
 422         max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
 423         if(physmem_size + iomem_size > max_physmem){
 424                 highmem = physmem_size + iomem_size - max_physmem;
 425                 physmem_size -= highmem;
 426 #ifndef CONFIG_HIGHMEM
 427                 highmem = 0;
 428                 printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
 429                        "to %Lu bytes\n", physmem_size);
 430 #endif
 431         }
 432
 433         high_physmem = uml_physmem + physmem_size;
 434         end_iomem = high_physmem + iomem_size;
 435         high_memory = (void *) end_iomem;
 436
 437         start_vm = VMALLOC_START;
 438
 439         setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
 440         if(init_maps(physmem_size, iomem_size, highmem)){
 441                 printf("Failed to allocate mem_map for %Lu bytes of physical "
 442                        "memory and %Lu bytes of highmem\n", physmem_size,
 443                        highmem);
 444                 exit(1);
 445         }
 446
 447         virtmem_size = physmem_size;
 448         avail = get_kmem_end() - start_vm;
 449         if(physmem_size > avail) virtmem_size = avail;
 450         end_vm = start_vm + virtmem_size;
 451
 452         if(virtmem_size < physmem_size)
 453                 printf("Kernel virtual memory size shrunk to %lu bytes\n",
 454                        virtmem_size);
 455
 456         uml_postsetup();
 457
 458         task_protections((unsigned long) &init_thread_info);
 459         os_flush_stdout();
 460
 461         return CHOOSE_MODE(start_uml_tt(), start_uml_skas());
 462 }
 463
 464 extern int uml_exitcode;
 465
 466 static int panic_exit(struct notifier_block *self, unsigned long unused1,
 467                       void *unused2)
 468 {
 469         bust_spinlocks(1);
 470         show_regs(&(current->thread.regs));
 471         bust_spinlocks(0);
 472         uml_exitcode = 1;
 473         machine_halt();
 474         return 0;
 475 }
 476
 477 static struct notifier_block panic_exit_notifier = {
 478         .notifier_call          = panic_exit,
 479         .next                   = NULL,
 480         .priority               = 0
 481 };
 482
 483 void __init setup_arch(char **cmdline_p)
 484 {
 485         atomic_notifier_chain_register(&panic_notifier_list,
 486                         &panic_exit_notifier);
 487         paging_init();
 488         strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 489         *cmdline_p = command_line;
 490         setup_hostinfo(host_info, sizeof host_info);
 491 }
 492
 493 void __init check_bugs(void)
 494 {
 495         arch_check_bugs();
 496         os_check_bugs();
 497 }
 498
 499 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 500 {
 501 }
 502
 503 #ifdef CONFIG_SMP
 504 void alternatives_smp_module_add(struct module *mod, char *name,
 505                                  void *locks, void *locks_end,
 506                                  void *text,  void *text_end)
 507 {
 508 }
 509
 510 void alternatives_smp_module_del(struct module *mod)
 511 {
 512 }
 513 #endif