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_MODE_TT
 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 physmem_size = 32 * 1024 * 1024;
 141
 142 void set_cmdline(char *cmd)
 143 {
 144 #ifdef CONFIG_MODE_TT
 145         char *umid, *ptr;
 146
 147         if(CHOOSE_MODE(honeypot, 0)) return;
 148
 149         umid = get_umid(1);
 150         if(umid != NULL){
 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 #ifdef CONFIG_SMP
 197 static int __init uml_ncpus_setup(char *line, int *add)
 198 {
 199        if (!sscanf(line, "%d", &ncpus)) {
 200                printf("Couldn't parse [%s]\n", line);
 201                return -1;
 202        }
 203
 204        return 0;
 205 }
 206
 207 __uml_setup("ncpus=", uml_ncpus_setup,
 208 "ncpus=<# of desired CPUs>\n"
 209 "    This tells an SMP kernel how many virtual processors to start.\n\n"
 210 );
 211 #endif
 212
 213 static int force_tt = 0;
 214
 215 #if defined(CONFIG_MODE_TT) && defined(CONFIG_MODE_SKAS)
 216 #define DEFAULT_TT 0
 217
 218 static int __init mode_tt_setup(char *line, int *add)
 219 {
 220         force_tt = 1;
 221         return(0);
 222 }
 223
 224 #else
 225 #ifdef CONFIG_MODE_SKAS
 226
 227 #define DEFAULT_TT 0
 228
 229 static int __init mode_tt_setup(char *line, int *add)
 230 {
 231         printf("CONFIG_MODE_TT disabled - 'mode=tt' ignored\n");
 232         return(0);
 233 }
 234
 235 #else
 236 #ifdef CONFIG_MODE_TT
 237
 238 #define DEFAULT_TT 1
 239
 240 static int __init mode_tt_setup(char *line, int *add)
 241 {
 242         printf("CONFIG_MODE_SKAS disabled - 'mode=tt' redundant\n");
 243         return(0);
 244 }
 245
 246 #else
 247
 248 #error Either CONFIG_MODE_TT or CONFIG_MODE_SKAS must be enabled
 249
 250 #endif
 251 #endif
 252 #endif
 253
 254 __uml_setup("mode=tt", mode_tt_setup,
 255 "mode=tt\n"
 256 "    When both CONFIG_MODE_TT and CONFIG_MODE_SKAS are enabled, this option\n"
 257 "    forces UML to run in tt (tracing thread) mode.  It is not the default\n"
 258 "    because it's slower and less secure than skas mode.\n\n"
 259 );
 260
 261 int mode_tt = DEFAULT_TT;
 262
 263 static int __init Usage(char *line, int *add)
 264 {
 265         const char **p;
 266
 267         printf(usage_string, system_utsname.release);
 268         p = &__uml_help_start;
 269         while (p < &__uml_help_end) {
 270                 printf("%s", *p);
 271                 p++;
 272         }
 273         exit(0);
 274
 275         return 0;
 276 }
 277
 278 __uml_setup("--help", Usage,
 279 "--help\n"
 280 "    Prints this message.\n\n"
 281 );
 282
 283 static int __init uml_checksetup(char *line, int *add)
 284 {
 285         struct uml_param *p;
 286
 287         p = &__uml_setup_start;
 288         while(p < &__uml_setup_end) {
 289                 int n;
 290
 291                 n = strlen(p->str);
 292                 if(!strncmp(line, p->str, n)){
 293                         if (p->setup_func(line + n, add)) return 1;
 294                 }
 295                 p++;
 296         }
 297         return 0;
 298 }
 299
 300 static void __init uml_postsetup(void)
 301 {
 302         initcall_t *p;
 303
 304         p = &__uml_postsetup_start;
 305         while(p < &__uml_postsetup_end){
 306                 (*p)();
 307                 p++;
 308         }
 309         return;
 310 }
 311
 312 /* Set during early boot */
 313 unsigned long brk_start;
 314 unsigned long end_iomem;
 315 EXPORT_SYMBOL(end_iomem);
 316
 317 #define MIN_VMALLOC (32 * 1024 * 1024)
 318
 319 int linux_main(int argc, char **argv)
 320 {
 321         unsigned long avail, diff;
 322         unsigned long virtmem_size, max_physmem;
 323         unsigned int i, add;
 324         char * mode;
 325
 326         for (i = 1; i < argc; i++){
 327                 if((i == 1) && (argv[i][0] == ' ')) continue;
 328                 add = 1;
 329                 uml_checksetup(argv[i], &add);
 330                 if (add)
 331                         add_arg(argv[i]);
 332         }
 333         if(have_root == 0)
 334                 add_arg(DEFAULT_COMMAND_LINE);
 335
 336         mode_tt = force_tt ? 1 : !can_do_skas();
 337 #ifndef CONFIG_MODE_TT
 338         if (mode_tt) {
 339                 /*Since CONFIG_MODE_TT is #undef'ed, force_tt cannot be 1. So,
 340                  * can_do_skas() returned 0, and the message is correct. */
 341                 printf("Support for TT mode is disabled, and no SKAS support is present on the host.\n");
 342                 exit(1);
 343         }
 344 #endif
 345
 346 #ifndef CONFIG_MODE_SKAS
 347         mode = "TT";
 348 #else
 349         /* Show to the user the result of selection */
 350         if (mode_tt)
 351                 mode = "TT";
 352         else if (proc_mm && ptrace_faultinfo)
 353                 mode = "SKAS3";
 354         else
 355                 mode = "SKAS0";
 356 #endif
 357
 358         printf("UML running in %s mode\n", mode);
 359
 360         uml_start = CHOOSE_MODE_PROC(set_task_sizes_tt, set_task_sizes_skas, 0,
 361                                      &host_task_size, &task_size);
 362
 363         /* Need to check this early because mmapping happens before the
 364          * kernel is running.
 365          */
 366         check_tmpexec();
 367
 368         brk_start = (unsigned long) sbrk(0);
 369         CHOOSE_MODE_PROC(before_mem_tt, before_mem_skas, brk_start);
 370         /* Increase physical memory size for exec-shield users
 371         so they actually get what they asked for. This should
 372         add zero for non-exec shield users */
 373
 374         diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 375         if(diff > 1024 * 1024){
 376                 printf("Adding %ld bytes to physical memory to account for "
 377                        "exec-shield gap\n", diff);
 378                 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 379         }
 380
 381         uml_physmem = uml_start;
 382
 383         /* Reserve up to 4M after the current brk */
 384         uml_reserved = ROUND_4M(brk_start) + (1 << 22);
 385
 386         setup_machinename(system_utsname.machine);
 387
 388 #ifdef CONFIG_MODE_TT
 389         argv1_begin = argv[1];
 390         argv1_end = &argv[1][strlen(argv[1])];
 391 #endif
 392
 393         highmem = 0;
 394         iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
 395         max_physmem = get_kmem_end() - uml_physmem - iomem_size - MIN_VMALLOC;
 396
 397         /* Zones have to begin on a 1 << MAX_ORDER page boundary,
 398          * so this makes sure that's true for highmem
 399          */
 400         max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
 401         if(physmem_size + iomem_size > max_physmem){
 402                 highmem = physmem_size + iomem_size - max_physmem;
 403                 physmem_size -= highmem;
 404 #ifndef CONFIG_HIGHMEM
 405                 highmem = 0;
 406                 printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
 407                        "to %ld bytes\n", physmem_size);
 408 #endif
 409         }
 410
 411         high_physmem = uml_physmem + physmem_size;
 412         end_iomem = high_physmem + iomem_size;
 413         high_memory = (void *) end_iomem;
 414
 415         start_vm = VMALLOC_START;
 416
 417         setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
 418         if(init_maps(physmem_size, iomem_size, highmem)){
 419                 printf("Failed to allocate mem_map for %ld bytes of physical "
 420                        "memory and %ld bytes of highmem\n", physmem_size,
 421                        highmem);
 422                 exit(1);
 423         }
 424
 425         virtmem_size = physmem_size;
 426         avail = get_kmem_end() - start_vm;
 427         if(physmem_size > avail) virtmem_size = avail;
 428         end_vm = start_vm + virtmem_size;
 429
 430         if(virtmem_size < physmem_size)
 431                 printf("Kernel virtual memory size shrunk to %ld bytes\n",
 432                        virtmem_size);
 433
 434         uml_postsetup();
 435
 436         task_protections((unsigned long) &init_thread_info);
 437         os_flush_stdout();
 438
 439         return(CHOOSE_MODE(start_uml_tt(), start_uml_skas()));
 440 }
 441
 442 extern int uml_exitcode;
 443
 444 static int panic_exit(struct notifier_block *self, unsigned long unused1,
 445                       void *unused2)
 446 {
 447         bust_spinlocks(1);
 448         show_regs(&(current->thread.regs));
 449         bust_spinlocks(0);
 450         uml_exitcode = 1;
 451         machine_halt();
 452         return(0);
 453 }
 454
 455 static struct notifier_block panic_exit_notifier = {
 456         .notifier_call          = panic_exit,
 457         .next                   = NULL,
 458         .priority               = 0
 459 };
 460
 461 void __init setup_arch(char **cmdline_p)
 462 {
 463         notifier_chain_register(&panic_notifier_list, &panic_exit_notifier);
 464         paging_init();
 465         strlcpy(saved_command_line, command_line, COMMAND_LINE_SIZE);
 466         *cmdline_p = command_line;
 467         setup_hostinfo();
 468 }
 469
 470 void __init check_bugs(void)
 471 {
 472         arch_check_bugs();
 473         check_ptrace();
 474         check_sigio();
 475         check_devanon();
 476 }
 477
 478 void apply_alternatives(void *start, void *end)
 479 {
 480 }