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