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