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 add_arg 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 /*
  62  * These fields are initialized at boot time and not changed.
  63  * XXX This structure is used only in the non-SMP case.  Maybe this
  64  * should be moved to smp.c.
  65  */
  66 struct cpuinfo_um boot_cpu_data = {
  67         .loops_per_jiffy        = 0,
  68         .ipi_pipe               = { -1, -1 }
  69 };
  70
  71 unsigned long thread_saved_pc(struct task_struct *task)
  72 {
  73         return os_process_pc(CHOOSE_MODE_PROC(thread_pid_tt, thread_pid_skas,
  74                                               task));
  75 }
  76
  77 /* Changed in setup_arch, which is called in early boot */
  78 static char host_info[(__NEW_UTS_LEN + 1) * 5];
  79
  80 static int show_cpuinfo(struct seq_file *m, void *v)
  81 {
  82         int index = 0;
  83
  84 #ifdef CONFIG_SMP
  85         index = (struct cpuinfo_um *) v - cpu_data;
  86         if (!cpu_online(index))
  87                 return 0;
  88 #endif
  89
  90         seq_printf(m, "processor\t: %d\n", index);
  91         seq_printf(m, "vendor_id\t: User Mode Linux\n");
  92         seq_printf(m, "model name\t: UML\n");
  93         seq_printf(m, "mode\t\t: %s\n", CHOOSE_MODE("tt", "skas"));
  94         seq_printf(m, "host\t\t: %s\n", host_info);
  95         seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
  96                    loops_per_jiffy/(500000/HZ),
  97                    (loops_per_jiffy/(5000/HZ)) % 100);
  98
  99         return 0;
 100 }
 101
 102 static void *c_start(struct seq_file *m, loff_t *pos)
 103 {
 104         return *pos < NR_CPUS ? cpu_data + *pos : NULL;
 105 }
 106
 107 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 108 {
 109         ++*pos;
 110         return c_start(m, pos);
 111 }
 112
 113 static void c_stop(struct seq_file *m, void *v)
 114 {
 115 }
 116
 117 const struct seq_operations cpuinfo_op = {
 118         .start  = c_start,
 119         .next   = c_next,
 120         .stop   = c_stop,
 121         .show   = show_cpuinfo,
 122 };
 123
 124 /* Set in linux_main */
 125 unsigned long host_task_size;
 126 unsigned long task_size;
 127 unsigned long uml_physmem;
 128 unsigned long uml_reserved; /* Also modified in mem_init */
 129 unsigned long start_vm;
 130 unsigned long end_vm;
 131
 132 /* Set in uml_ncpus_setup */
 133 int ncpus = 1;
 134
 135 #ifdef CONFIG_CMDLINE_ON_HOST
 136 /* Pointer set in linux_main, the array itself is private to each thread,
 137  * and changed at address space creation time so this poses no concurrency
 138  * problems.
 139  */
 140 static char *argv1_begin = NULL;
 141 static char *argv1_end = NULL;
 142 #endif
 143
 144 /* Set in early boot */
 145 static int have_root __initdata = 0;
 146
 147 /* Set in uml_mem_setup and modified in linux_main */
 148 long long physmem_size = 32 * 1024 * 1024;
 149
 150 void set_cmdline(char *cmd)
 151 {
 152 #ifdef CONFIG_CMDLINE_ON_HOST
 153         char *umid, *ptr;
 154
 155         if(CHOOSE_MODE(honeypot, 0)) return;
 156
 157         umid = get_umid();
 158         if(*umid != '\0'){
 159                 snprintf(argv1_begin,
 160                          (argv1_end - argv1_begin) * sizeof(*ptr),
 161                          "(%s) ", umid);
 162                 ptr = &argv1_begin[strlen(argv1_begin)];
 163         }
 164         else ptr = argv1_begin;
 165
 166         snprintf(ptr, (argv1_end - ptr) * sizeof(*ptr), "[%s]", cmd);
 167         memset(argv1_begin + strlen(argv1_begin), '\0',
 168                argv1_end - argv1_begin - strlen(argv1_begin));
 169 #endif
 170 }
 171
 172 static char *usage_string =
 173 "User Mode Linux v%s\n"
 174 "       available at http://user-mode-linux.sourceforge.net/\n\n";
 175
 176 static int __init uml_version_setup(char *line, int *add)
 177 {
 178         printf("%s\n", init_utsname()->release);
 179         exit(0);
 180
 181         return 0;
 182 }
 183
 184 __uml_setup("--version", uml_version_setup,
 185 "--version\n"
 186 "    Prints the version number of the kernel.\n\n"
 187 );
 188
 189 static int __init uml_root_setup(char *line, int *add)
 190 {
 191         have_root = 1;
 192         return 0;
 193 }
 194
 195 __uml_setup("root=", uml_root_setup,
 196 "root=<file containing the root fs>\n"
 197 "    This is actually used by the generic kernel in exactly the same\n"
 198 "    way as in any other kernel. If you configure a number of block\n"
 199 "    devices and want to boot off something other than ubd0, you \n"
 200 "    would use something like:\n"
 201 "        root=/dev/ubd5\n\n"
 202 );
 203
 204 #ifndef CONFIG_MODE_TT
 205
 206 static int __init no_skas_debug_setup(char *line, int *add)
 207 {
 208         printf("'debug' is not necessary to gdb UML in skas mode - run \n");
 209         printf("'gdb linux' and disable CONFIG_CMDLINE_ON_HOST if gdb \n");
 210         printf("doesn't work as expected\n");
 211
 212         return 0;
 213 }
 214
 215 __uml_setup("debug", no_skas_debug_setup,
 216 "debug\n"
 217 "    this flag is not needed to run gdb on UML in skas mode\n\n"
 218 );
 219
 220 #endif
 221
 222 #ifdef CONFIG_SMP
 223 static int __init uml_ncpus_setup(char *line, int *add)
 224 {
 225         if (!sscanf(line, "%d", &ncpus)) {
 226                 printf("Couldn't parse [%s]\n", line);
 227                 return -1;
 228         }
 229
 230         return 0;
 231 }
 232
 233 __uml_setup("ncpus=", uml_ncpus_setup,
 234 "ncpus=<# of desired CPUs>\n"
 235 "    This tells an SMP kernel how many virtual processors to start.\n\n"
 236 );
 237 #endif
 238
 239 static int force_tt = 0;
 240
 241 #if defined(CONFIG_MODE_TT) && defined(CONFIG_MODE_SKAS)
 242 #define DEFAULT_TT 0
 243
 244 static int __init mode_tt_setup(char *line, int *add)
 245 {
 246         force_tt = 1;
 247         return 0;
 248 }
 249
 250 #else
 251 #ifdef CONFIG_MODE_SKAS
 252
 253 #define DEFAULT_TT 0
 254
 255 static int __init mode_tt_setup(char *line, int *add)
 256 {
 257         printf("CONFIG_MODE_TT disabled - 'mode=tt' ignored\n");
 258         return 0;
 259 }
 260
 261 #else
 262 #ifdef CONFIG_MODE_TT
 263
 264 #define DEFAULT_TT 1
 265
 266 static int __init mode_tt_setup(char *line, int *add)
 267 {
 268         printf("CONFIG_MODE_SKAS disabled - 'mode=tt' redundant\n");
 269         return 0;
 270 }
 271
 272 #endif
 273 #endif
 274 #endif
 275
 276 __uml_setup("mode=tt", mode_tt_setup,
 277 "mode=tt\n"
 278 "    When both CONFIG_MODE_TT and CONFIG_MODE_SKAS are enabled, this option\n"
 279 "    forces UML to run in tt (tracing thread) mode.  It is not the default\n"
 280 "    because it's slower and less secure than skas mode.\n\n"
 281 );
 282
 283 int mode_tt = DEFAULT_TT;
 284
 285 static int __init Usage(char *line, int *add)
 286 {
 287         const char **p;
 288
 289         printf(usage_string, init_utsname()->release);
 290         p = &__uml_help_start;
 291         while (p < &__uml_help_end) {
 292                 printf("%s", *p);
 293                 p++;
 294         }
 295         exit(0);
 296         return 0;
 297 }
 298
 299 __uml_setup("--help", Usage,
 300 "--help\n"
 301 "    Prints this message.\n\n"
 302 );
 303
 304 static int __init uml_checksetup(char *line, int *add)
 305 {
 306         struct uml_param *p;
 307
 308         p = &__uml_setup_start;
 309         while(p < &__uml_setup_end) {
 310                 int n;
 311
 312                 n = strlen(p->str);
 313                 if(!strncmp(line, p->str, n)){
 314                         if (p->setup_func(line + n, add)) return 1;
 315                 }
 316                 p++;
 317         }
 318         return 0;
 319 }
 320
 321 static void __init uml_postsetup(void)
 322 {
 323         initcall_t *p;
 324
 325         p = &__uml_postsetup_start;
 326         while(p < &__uml_postsetup_end){
 327                 (*p)();
 328                 p++;
 329         }
 330         return;
 331 }
 332
 333 /* Set during early boot */
 334 unsigned long brk_start;
 335 unsigned long end_iomem;
 336 EXPORT_SYMBOL(end_iomem);
 337
 338 #define MIN_VMALLOC (32 * 1024 * 1024)
 339
 340 extern char __binary_start;
 341
 342 int __init linux_main(int argc, char **argv)
 343 {
 344         unsigned long avail, diff;
 345         unsigned long virtmem_size, max_physmem;
 346         unsigned int i, add;
 347         char * mode;
 348
 349         for (i = 1; i < argc; i++){
 350                 if((i == 1) && (argv[i][0] == ' ')) continue;
 351                 add = 1;
 352                 uml_checksetup(argv[i], &add);
 353                 if (add)
 354                         add_arg(argv[i]);
 355         }
 356         if(have_root == 0)
 357                 add_arg(DEFAULT_COMMAND_LINE);
 358
 359         os_early_checks();
 360         if (force_tt)
 361                 clear_can_do_skas();
 362         mode_tt = force_tt ? 1 : !can_do_skas();
 363 #ifndef CONFIG_MODE_TT
 364         if (mode_tt) {
 365                 /*Since CONFIG_MODE_TT is #undef'ed, force_tt cannot be 1. So,
 366                  * can_do_skas() returned 0, and the message is correct. */
 367                 printf("Support for TT mode is disabled, and no SKAS support is present on the host.\n");
 368                 exit(1);
 369         }
 370 #endif
 371
 372 #ifndef CONFIG_MODE_SKAS
 373         mode = "TT";
 374 #else
 375         /* Show to the user the result of selection */
 376         if (mode_tt)
 377                 mode = "TT";
 378         else if (proc_mm && ptrace_faultinfo)
 379                 mode = "SKAS3";
 380         else
 381                 mode = "SKAS0";
 382 #endif
 383
 384         printf("UML running in %s mode\n", mode);
 385
 386         host_task_size = CHOOSE_MODE_PROC(set_task_sizes_tt,
 387                                           set_task_sizes_skas, &task_size);
 388
 389         /*
 390          * Setting up handlers to 'sig_info' struct
 391          */
 392         os_fill_handlinfo(handlinfo_kern);
 393
 394         brk_start = (unsigned long) sbrk(0);
 395         CHOOSE_MODE_PROC(before_mem_tt, before_mem_skas, brk_start);
 396         /* Increase physical memory size for exec-shield users
 397         so they actually get what they asked for. This should
 398         add zero for non-exec shield users */
 399
 400         diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 401         if(diff > 1024 * 1024){
 402                 printf("Adding %ld bytes to physical memory to account for "
 403                        "exec-shield gap\n", diff);
 404                 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 405         }
 406
 407         uml_physmem = (unsigned long) &__binary_start & PAGE_MASK;
 408
 409         /* Reserve up to 4M after the current brk */
 410         uml_reserved = ROUND_4M(brk_start) + (1 << 22);
 411
 412         setup_machinename(init_utsname()->machine);
 413
 414 #ifdef CONFIG_CMDLINE_ON_HOST
 415         argv1_begin = argv[1];
 416         argv1_end = &argv[1][strlen(argv[1])];
 417 #endif
 418
 419         highmem = 0;
 420         iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
 421         max_physmem = get_kmem_end() - uml_physmem - iomem_size - MIN_VMALLOC;
 422
 423         /* Zones have to begin on a 1 << MAX_ORDER page boundary,
 424          * so this makes sure that's true for highmem
 425          */
 426         max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
 427         if(physmem_size + iomem_size > max_physmem){
 428                 highmem = physmem_size + iomem_size - max_physmem;
 429                 physmem_size -= highmem;
 430 #ifndef CONFIG_HIGHMEM
 431                 highmem = 0;
 432                 printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
 433                        "to %Lu bytes\n", physmem_size);
 434 #endif
 435         }
 436
 437         high_physmem = uml_physmem + physmem_size;
 438         end_iomem = high_physmem + iomem_size;
 439         high_memory = (void *) end_iomem;
 440
 441         start_vm = VMALLOC_START;
 442
 443         setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
 444         if(init_maps(physmem_size, iomem_size, highmem)){
 445                 printf("Failed to allocate mem_map for %Lu bytes of physical "
 446                        "memory and %Lu bytes of highmem\n", physmem_size,
 447                        highmem);
 448                 exit(1);
 449         }
 450
 451         virtmem_size = physmem_size;
 452         avail = get_kmem_end() - start_vm;
 453         if(physmem_size > avail) virtmem_size = avail;
 454         end_vm = start_vm + virtmem_size;
 455
 456         if(virtmem_size < physmem_size)
 457                 printf("Kernel virtual memory size shrunk to %lu bytes\n",
 458                        virtmem_size);
 459
 460         uml_postsetup();
 461
 462         stack_protections((unsigned long) &init_thread_info);
 463         os_flush_stdout();
 464
 465         return CHOOSE_MODE(start_uml_tt(), start_uml_skas());
 466 }
 467
 468 extern int uml_exitcode;
 469
 470 static int panic_exit(struct notifier_block *self, unsigned long unused1,
 471                       void *unused2)
 472 {
 473         bust_spinlocks(1);
 474         show_regs(&(current->thread.regs));
 475         bust_spinlocks(0);
 476         uml_exitcode = 1;
 477         os_dump_core();
 478         return 0;
 479 }
 480
 481 static struct notifier_block panic_exit_notifier = {
 482         .notifier_call          = panic_exit,
 483         .next                   = NULL,
 484         .priority               = 0
 485 };
 486
 487 void __init setup_arch(char **cmdline_p)
 488 {
 489         atomic_notifier_chain_register(&panic_notifier_list,
 490                         &panic_exit_notifier);
 491         paging_init();
 492         strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 493         *cmdline_p = command_line;
 494         setup_hostinfo(host_info, sizeof host_info);
 495 }
 496
 497 void __init check_bugs(void)
 498 {
 499         arch_check_bugs();
 500         os_check_bugs();
 501 }
 502
 503 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 504 {
 505 }
 506
 507 #ifdef CONFIG_SMP
 508 void alternatives_smp_module_add(struct module *mod, char *name,
 509                                  void *locks, void *locks_end,
 510                                  void *text,  void *text_end)
 511 {
 512 }
 513
 514 void alternatives_smp_module_del(struct module *mod)
 515 {
 516 }
 517 #endif