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 "user_util.h"
  30 #include "kern_util.h"
  31 #include "as-layout.h"
  32 #include "arch.h"
  33 #include "kern.h"
  34 #include "mem_user.h"
  35 #include "mem.h"
  36 #include "initrd.h"
  37 #include "init.h"
  38 #include "os.h"
  39 #include "choose-mode.h"
  40 #include "mode_kern.h"
  41 #include "mode.h"
  42 #ifdef UML_CONFIG_MODE_SKAS
  43 #include "skas.h"
  44 #endif
  45
  46 #define DEFAULT_COMMAND_LINE "root=98:0"
  47
  48 /* Changed in linux_main and setup_arch, which run before SMP is started */
  49 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
  50
  51 static void __init add_arg(char *arg)
  52 {
  53         if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
  54                 printf("add_arg: Too many command line arguments!\n");
  55                 exit(1);
  56         }
  57         if(strlen(command_line) > 0)
  58                 strcat(command_line, " ");
  59         strcat(command_line, arg);
  60 }
  61
  62 struct cpuinfo_um boot_cpu_data = {
  63         .loops_per_jiffy        = 0,
  64         .ipi_pipe               = { -1, -1 }
  65 };
  66
  67 unsigned long thread_saved_pc(struct task_struct *task)
  68 {
  69         return os_process_pc(CHOOSE_MODE_PROC(thread_pid_tt, thread_pid_skas,
  70                                               task));
  71 }
  72
  73 /* Changed in setup_arch, which is called in early boot */
  74 static char host_info[(__NEW_UTS_LEN + 1) * 5];
  75
  76 static int show_cpuinfo(struct seq_file *m, void *v)
  77 {
  78         int index = 0;
  79
  80 #ifdef CONFIG_SMP
  81         index = (struct cpuinfo_um *) v - cpu_data;
  82         if (!cpu_online(index))
  83                 return 0;
  84 #endif
  85
  86         seq_printf(m, "processor\t: %d\n", index);
  87         seq_printf(m, "vendor_id\t: User Mode Linux\n");
  88         seq_printf(m, "model name\t: UML\n");
  89         seq_printf(m, "mode\t\t: %s\n", CHOOSE_MODE("tt", "skas"));
  90         seq_printf(m, "host\t\t: %s\n", host_info);
  91         seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
  92                    loops_per_jiffy/(500000/HZ),
  93                    (loops_per_jiffy/(5000/HZ)) % 100);
  94
  95         return 0;
  96 }
  97
  98 static void *c_start(struct seq_file *m, loff_t *pos)
  99 {
 100         return *pos < NR_CPUS ? cpu_data + *pos : NULL;
 101 }
 102
 103 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 104 {
 105         ++*pos;
 106         return c_start(m, pos);
 107 }
 108
 109 static void c_stop(struct seq_file *m, void *v)
 110 {
 111 }
 112
 113 const struct seq_operations cpuinfo_op = {
 114         .start  = c_start,
 115         .next   = c_next,
 116         .stop   = c_stop,
 117         .show   = show_cpuinfo,
 118 };
 119
 120 /* Set in linux_main */
 121 unsigned long host_task_size;
 122 unsigned long task_size;
 123
 124 unsigned long uml_start;
 125
 126 /* Set in early boot */
 127 unsigned long uml_physmem;
 128 unsigned long uml_reserved;
 129 unsigned long start_vm;
 130 unsigned long end_vm;
 131 int ncpus = 1;
 132
 133 #ifdef CONFIG_CMDLINE_ON_HOST
 134 /* Pointer set in linux_main, the array itself is private to each thread,
 135  * and changed at address space creation time so this poses no concurrency
 136  * problems.
 137  */
 138 static char *argv1_begin = NULL;
 139 static char *argv1_end = NULL;
 140 #endif
 141
 142 /* Set in early boot */
 143 static int have_root __initdata = 0;
 144 long long physmem_size = 32 * 1024 * 1024;
 145
 146 void set_cmdline(char *cmd)
 147 {
 148 #ifdef CONFIG_CMDLINE_ON_HOST
 149         char *umid, *ptr;
 150
 151         if(CHOOSE_MODE(honeypot, 0)) return;
 152
 153         umid = get_umid();
 154         if(*umid != '\0'){
 155                 snprintf(argv1_begin,
 156                          (argv1_end - argv1_begin) * sizeof(*ptr),
 157                          "(%s) ", umid);
 158                 ptr = &argv1_begin[strlen(argv1_begin)];
 159         }
 160         else ptr = argv1_begin;
 161
 162         snprintf(ptr, (argv1_end - ptr) * sizeof(*ptr), "[%s]", cmd);
 163         memset(argv1_begin + strlen(argv1_begin), '\0',
 164                argv1_end - argv1_begin - strlen(argv1_begin));
 165 #endif
 166 }
 167
 168 static char *usage_string =
 169 "User Mode Linux v%s\n"
 170 "       available at http://user-mode-linux.sourceforge.net/\n\n";
 171
 172 static int __init uml_version_setup(char *line, int *add)
 173 {
 174         printf("%s\n", init_utsname()->release);
 175         exit(0);
 176
 177         return 0;
 178 }
 179
 180 __uml_setup("--version", uml_version_setup,
 181 "--version\n"
 182 "    Prints the version number of the kernel.\n\n"
 183 );
 184
 185 static int __init uml_root_setup(char *line, int *add)
 186 {
 187         have_root = 1;
 188         return 0;
 189 }
 190
 191 __uml_setup("root=", uml_root_setup,
 192 "root=<file containing the root fs>\n"
 193 "    This is actually used by the generic kernel in exactly the same\n"
 194 "    way as in any other kernel. If you configure a number of block\n"
 195 "    devices and want to boot off something other than ubd0, you \n"
 196 "    would use something like:\n"
 197 "        root=/dev/ubd5\n\n"
 198 );
 199
 200 #ifndef CONFIG_MODE_TT
 201
 202 static int __init no_skas_debug_setup(char *line, int *add)
 203 {
 204         printf("'debug' is not necessary to gdb UML in skas mode - run \n");
 205         printf("'gdb linux' and disable CONFIG_CMDLINE_ON_HOST if gdb \n");
 206         printf("doesn't work as expected\n");
 207
 208         return 0;
 209 }
 210
 211 __uml_setup("debug", no_skas_debug_setup,
 212 "debug\n"
 213 "    this flag is not needed to run gdb on UML in skas mode\n\n"
 214 );
 215
 216 #endif
 217
 218 #ifdef CONFIG_SMP
 219 static int __init uml_ncpus_setup(char *line, int *add)
 220 {
 221         if (!sscanf(line, "%d", &ncpus)) {
 222                 printf("Couldn't parse [%s]\n", line);
 223                 return -1;
 224         }
 225
 226         return 0;
 227 }
 228
 229 __uml_setup("ncpus=", uml_ncpus_setup,
 230 "ncpus=<# of desired CPUs>\n"
 231 "    This tells an SMP kernel how many virtual processors to start.\n\n"
 232 );
 233 #endif
 234
 235 static int force_tt = 0;
 236
 237 #if defined(CONFIG_MODE_TT) && defined(CONFIG_MODE_SKAS)
 238 #define DEFAULT_TT 0
 239
 240 static int __init mode_tt_setup(char *line, int *add)
 241 {
 242         force_tt = 1;
 243         return 0;
 244 }
 245
 246 #else
 247 #ifdef CONFIG_MODE_SKAS
 248
 249 #define DEFAULT_TT 0
 250
 251 static int __init mode_tt_setup(char *line, int *add)
 252 {
 253         printf("CONFIG_MODE_TT disabled - 'mode=tt' ignored\n");
 254         return 0;
 255 }
 256
 257 #else
 258 #ifdef CONFIG_MODE_TT
 259
 260 #define DEFAULT_TT 1
 261
 262 static int __init mode_tt_setup(char *line, int *add)
 263 {
 264         printf("CONFIG_MODE_SKAS disabled - 'mode=tt' redundant\n");
 265         return 0;
 266 }
 267
 268 #endif
 269 #endif
 270 #endif
 271
 272 __uml_setup("mode=tt", mode_tt_setup,
 273 "mode=tt\n"
 274 "    When both CONFIG_MODE_TT and CONFIG_MODE_SKAS are enabled, this option\n"
 275 "    forces UML to run in tt (tracing thread) mode.  It is not the default\n"
 276 "    because it's slower and less secure than skas mode.\n\n"
 277 );
 278
 279 int mode_tt = DEFAULT_TT;
 280
 281 static int __init Usage(char *line, int *add)
 282 {
 283         const char **p;
 284
 285         printf(usage_string, init_utsname()->release);
 286         p = &__uml_help_start;
 287         while (p < &__uml_help_end) {
 288                 printf("%s", *p);
 289                 p++;
 290         }
 291         exit(0);
 292         return 0;
 293 }
 294
 295 __uml_setup("--help", Usage,
 296 "--help\n"
 297 "    Prints this message.\n\n"
 298 );
 299
 300 static int __init uml_checksetup(char *line, int *add)
 301 {
 302         struct uml_param *p;
 303
 304         p = &__uml_setup_start;
 305         while(p < &__uml_setup_end) {
 306                 int n;
 307
 308                 n = strlen(p->str);
 309                 if(!strncmp(line, p->str, n)){
 310                         if (p->setup_func(line + n, add)) return 1;
 311                 }
 312                 p++;
 313         }
 314         return 0;
 315 }
 316
 317 static void __init uml_postsetup(void)
 318 {
 319         initcall_t *p;
 320
 321         p = &__uml_postsetup_start;
 322         while(p < &__uml_postsetup_end){
 323                 (*p)();
 324                 p++;
 325         }
 326         return;
 327 }
 328
 329 /* Set during early boot */
 330 unsigned long brk_start;
 331 unsigned long end_iomem;
 332 EXPORT_SYMBOL(end_iomem);
 333
 334 #define MIN_VMALLOC (32 * 1024 * 1024)
 335
 336 extern char __binary_start;
 337
 338 int __init linux_main(int argc, char **argv)
 339 {
 340         unsigned long avail, diff;
 341         unsigned long virtmem_size, max_physmem;
 342         unsigned int i, add;
 343         char * mode;
 344
 345         for (i = 1; i < argc; i++){
 346                 if((i == 1) && (argv[i][0] == ' ')) continue;
 347                 add = 1;
 348                 uml_checksetup(argv[i], &add);
 349                 if (add)
 350                         add_arg(argv[i]);
 351         }
 352         if(have_root == 0)
 353                 add_arg(DEFAULT_COMMAND_LINE);
 354
 355         os_early_checks();
 356         if (force_tt)
 357                 clear_can_do_skas();
 358         mode_tt = force_tt ? 1 : !can_do_skas();
 359 #ifndef CONFIG_MODE_TT
 360         if (mode_tt) {
 361                 /*Since CONFIG_MODE_TT is #undef'ed, force_tt cannot be 1. So,
 362                  * can_do_skas() returned 0, and the message is correct. */
 363                 printf("Support for TT mode is disabled, and no SKAS support is present on the host.\n");
 364                 exit(1);
 365         }
 366 #endif
 367
 368 #ifndef CONFIG_MODE_SKAS
 369         mode = "TT";
 370 #else
 371         /* Show to the user the result of selection */
 372         if (mode_tt)
 373                 mode = "TT";
 374         else if (proc_mm && ptrace_faultinfo)
 375                 mode = "SKAS3";
 376         else
 377                 mode = "SKAS0";
 378 #endif
 379
 380         printf("UML running in %s mode\n", mode);
 381
 382         uml_start = (unsigned long) &__binary_start;
 383         host_task_size = CHOOSE_MODE_PROC(set_task_sizes_tt,
 384                                           set_task_sizes_skas, &task_size);
 385
 386         /*
 387          * Setting up handlers to 'sig_info' struct
 388          */
 389         os_fill_handlinfo(handlinfo_kern);
 390
 391         brk_start = (unsigned long) sbrk(0);
 392         CHOOSE_MODE_PROC(before_mem_tt, before_mem_skas, brk_start);
 393         /* Increase physical memory size for exec-shield users
 394         so they actually get what they asked for. This should
 395         add zero for non-exec shield users */
 396
 397         diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 398         if(diff > 1024 * 1024){
 399                 printf("Adding %ld bytes to physical memory to account for "
 400                        "exec-shield gap\n", diff);
 401                 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 402         }
 403
 404         uml_physmem = uml_start & PAGE_MASK;
 405
 406         /* Reserve up to 4M after the current brk */
 407         uml_reserved = ROUND_4M(brk_start) + (1 << 22);
 408
 409         setup_machinename(init_utsname()->machine);
 410
 411 #ifdef CONFIG_CMDLINE_ON_HOST
 412         argv1_begin = argv[1];
 413         argv1_end = &argv[1][strlen(argv[1])];
 414 #endif
 415
 416         highmem = 0;
 417         iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
 418         max_physmem = get_kmem_end() - uml_physmem - iomem_size - MIN_VMALLOC;
 419
 420         /* Zones have to begin on a 1 << MAX_ORDER page boundary,
 421          * so this makes sure that's true for highmem
 422          */
 423         max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
 424         if(physmem_size + iomem_size > max_physmem){
 425                 highmem = physmem_size + iomem_size - max_physmem;
 426                 physmem_size -= highmem;
 427 #ifndef CONFIG_HIGHMEM
 428                 highmem = 0;
 429                 printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
 430                        "to %Lu bytes\n", physmem_size);
 431 #endif
 432         }
 433
 434         high_physmem = uml_physmem + physmem_size;
 435         end_iomem = high_physmem + iomem_size;
 436         high_memory = (void *) end_iomem;
 437
 438         start_vm = VMALLOC_START;
 439
 440         setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
 441         if(init_maps(physmem_size, iomem_size, highmem)){
 442                 printf("Failed to allocate mem_map for %Lu bytes of physical "
 443                        "memory and %Lu bytes of highmem\n", physmem_size,
 444                        highmem);
 445                 exit(1);
 446         }
 447
 448         virtmem_size = physmem_size;
 449         avail = get_kmem_end() - start_vm;
 450         if(physmem_size > avail) virtmem_size = avail;
 451         end_vm = start_vm + virtmem_size;
 452
 453         if(virtmem_size < physmem_size)
 454                 printf("Kernel virtual memory size shrunk to %lu bytes\n",
 455                        virtmem_size);
 456
 457         uml_postsetup();
 458
 459         task_protections((unsigned long) &init_thread_info);
 460         os_flush_stdout();
 461
 462         return CHOOSE_MODE(start_uml_tt(), start_uml_skas());
 463 }
 464
 465 extern int uml_exitcode;
 466
 467 static int panic_exit(struct notifier_block *self, unsigned long unused1,
 468                       void *unused2)
 469 {
 470         bust_spinlocks(1);
 471         show_regs(&(current->thread.regs));
 472         bust_spinlocks(0);
 473         uml_exitcode = 1;
 474         machine_halt();
 475         return 0;
 476 }
 477
 478 static struct notifier_block panic_exit_notifier = {
 479         .notifier_call          = panic_exit,
 480         .next                   = NULL,
 481         .priority               = 0
 482 };
 483
 484 void __init setup_arch(char **cmdline_p)
 485 {
 486         atomic_notifier_chain_register(&panic_notifier_list,
 487                         &panic_exit_notifier);
 488         paging_init();
 489         strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 490         *cmdline_p = command_line;
 491         setup_hostinfo(host_info, sizeof host_info);
 492 }
 493
 494 void __init check_bugs(void)
 495 {
 496         arch_check_bugs();
 497         os_check_bugs();
 498 }
 499
 500 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 501 {
 502 }
 503
 504 #ifdef CONFIG_SMP
 505 void alternatives_smp_module_add(struct module *mod, char *name,
 506                                  void *locks, void *locks_end,
 507                                  void *text,  void *text_end)
 508 {
 509 }
 510
 511 void alternatives_smp_module_del(struct module *mod)
 512 {
 513 }
 514 #endif