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 "asm/setup.h"
  30 #include "user_util.h"
  31 #include "kern_util.h"
  32 #include "kern.h"
  33 #include "mem_user.h"
  34 #include "mem.h"
  35 #include "umid.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
  43 #define DEFAULT_COMMAND_LINE "root=98:0"
  44
  45 /* Changed in linux_main and setup_arch, which run before SMP is started */
  46 static char command_line[COMMAND_LINE_SIZE] = { 0 };
  47
  48 static void add_arg(char *arg)
  49 {
  50         if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
  51                 printf("add_arg: Too many command line arguments!\n");
  52                 exit(1);
  53         }
  54         if(strlen(command_line) > 0)
  55                 strcat(command_line, " ");
  56         strcat(command_line, arg);
  57 }
  58
  59 struct cpuinfo_um boot_cpu_data = {
  60         .loops_per_jiffy        = 0,
  61         .ipi_pipe               = { -1, -1 }
  62 };
  63
  64 unsigned long thread_saved_pc(struct task_struct *task)
  65 {
  66         return(os_process_pc(CHOOSE_MODE_PROC(thread_pid_tt, thread_pid_skas,
  67                                               task)));
  68 }
  69
  70 static int show_cpuinfo(struct seq_file *m, void *v)
  71 {
  72         int index = 0;
  73
  74 #ifdef CONFIG_SMP
  75         index = (struct cpuinfo_um *) v - cpu_data;
  76         if (!cpu_online(index))
  77                 return 0;
  78 #endif
  79
  80         seq_printf(m, "processor\t: %d\n", index);
  81         seq_printf(m, "vendor_id\t: User Mode Linux\n");
  82         seq_printf(m, "model name\t: UML\n");
  83         seq_printf(m, "mode\t\t: %s\n", CHOOSE_MODE("tt", "skas"));
  84         seq_printf(m, "host\t\t: %s\n", host_info);
  85         seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
  86                    loops_per_jiffy/(500000/HZ),
  87                    (loops_per_jiffy/(5000/HZ)) % 100);
  88
  89         return(0);
  90 }
  91
  92 static void *c_start(struct seq_file *m, loff_t *pos)
  93 {
  94         return *pos < NR_CPUS ? cpu_data + *pos : NULL;
  95 }
  96
  97 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
  98 {
  99         ++*pos;
 100         return c_start(m, pos);
 101 }
 102
 103 static void c_stop(struct seq_file *m, void *v)
 104 {
 105 }
 106
 107 struct seq_operations cpuinfo_op = {
 108         .start  = c_start,
 109         .next   = c_next,
 110         .stop   = c_stop,
 111         .show   = show_cpuinfo,
 112 };
 113
 114 pte_t * __bad_pagetable(void)
 115 {
 116         panic("Someone should implement __bad_pagetable");
 117         return(NULL);
 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_MODE_TT
 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 physmem_size = 32 * 1024 * 1024;
 145
 146 void set_cmdline(char *cmd)
 147 {
 148 #ifdef CONFIG_MODE_TT
 149         char *umid, *ptr;
 150
 151         if(CHOOSE_MODE(honeypot, 0)) return;
 152
 153         umid = get_umid(1);
 154         if(umid != NULL){
 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", system_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 #ifdef CONFIG_SMP
 201 static int __init uml_ncpus_setup(char *line, int *add)
 202 {
 203        if (!sscanf(line, "%d", &ncpus)) {
 204                printf("Couldn't parse [%s]\n", line);
 205                return -1;
 206        }
 207
 208        return 0;
 209 }
 210
 211 __uml_setup("ncpus=", uml_ncpus_setup,
 212 "ncpus=<# of desired CPUs>\n"
 213 "    This tells an SMP kernel how many virtual processors to start.\n\n"
 214 );
 215 #endif
 216
 217 static int force_tt = 0;
 218
 219 #if defined(CONFIG_MODE_TT) && defined(CONFIG_MODE_SKAS)
 220 #define DEFAULT_TT 0
 221
 222 static int __init mode_tt_setup(char *line, int *add)
 223 {
 224         force_tt = 1;
 225         return(0);
 226 }
 227
 228 #else
 229 #ifdef CONFIG_MODE_SKAS
 230
 231 #define DEFAULT_TT 0
 232
 233 static int __init mode_tt_setup(char *line, int *add)
 234 {
 235         printf("CONFIG_MODE_TT disabled - 'mode=tt' ignored\n");
 236         return(0);
 237 }
 238
 239 #else
 240 #ifdef CONFIG_MODE_TT
 241
 242 #define DEFAULT_TT 1
 243
 244 static int __init mode_tt_setup(char *line, int *add)
 245 {
 246         printf("CONFIG_MODE_SKAS disabled - 'mode=tt' redundant\n");
 247         return(0);
 248 }
 249
 250 #else
 251
 252 #error Either CONFIG_MODE_TT or CONFIG_MODE_SKAS must be enabled
 253
 254 #endif
 255 #endif
 256 #endif
 257
 258 __uml_setup("mode=tt", mode_tt_setup,
 259 "mode=tt\n"
 260 "    When both CONFIG_MODE_TT and CONFIG_MODE_SKAS are enabled, this option\n"
 261 "    forces UML to run in tt (tracing thread) mode.  It is not the default\n"
 262 "    because it's slower and less secure than skas mode.\n\n"
 263 );
 264
 265 int mode_tt = DEFAULT_TT;
 266
 267 static int __init Usage(char *line, int *add)
 268 {
 269         const char **p;
 270
 271         printf(usage_string, system_utsname.release);
 272         p = &__uml_help_start;
 273         while (p < &__uml_help_end) {
 274                 printf("%s", *p);
 275                 p++;
 276         }
 277         exit(0);
 278
 279         return 0;
 280 }
 281
 282 __uml_setup("--help", Usage,
 283 "--help\n"
 284 "    Prints this message.\n\n"
 285 );
 286
 287 static int __init uml_checksetup(char *line, int *add)
 288 {
 289         struct uml_param *p;
 290
 291         p = &__uml_setup_start;
 292         while(p < &__uml_setup_end) {
 293                 int n;
 294
 295                 n = strlen(p->str);
 296                 if(!strncmp(line, p->str, n)){
 297                         if (p->setup_func(line + n, add)) return 1;
 298                 }
 299                 p++;
 300         }
 301         return 0;
 302 }
 303
 304 static void __init uml_postsetup(void)
 305 {
 306         initcall_t *p;
 307
 308         p = &__uml_postsetup_start;
 309         while(p < &__uml_postsetup_end){
 310                 (*p)();
 311                 p++;
 312         }
 313         return;
 314 }
 315
 316 /* Set during early boot */
 317 unsigned long brk_start;
 318 unsigned long end_iomem;
 319 EXPORT_SYMBOL(end_iomem);
 320
 321 #define MIN_VMALLOC (32 * 1024 * 1024)
 322
 323 int linux_main(int argc, char **argv)
 324 {
 325         unsigned long avail, diff;
 326         unsigned long virtmem_size, max_physmem;
 327         unsigned int i, add;
 328
 329         for (i = 1; i < argc; i++){
 330                 if((i == 1) && (argv[i][0] == ' ')) continue;
 331                 add = 1;
 332                 uml_checksetup(argv[i], &add);
 333                 if (add)
 334                         add_arg(argv[i]);
 335         }
 336         if(have_root == 0)
 337                 add_arg(DEFAULT_COMMAND_LINE);
 338
 339         mode_tt = force_tt ? 1 : !can_do_skas();
 340 #ifndef CONFIG_MODE_TT
 341         if (mode_tt) {
 342                 /*Since CONFIG_MODE_TT is #undef'ed, force_tt cannot be 1. So,
 343                  * can_do_skas() returned 0, and the message is correct. */
 344                 printf("Support for TT mode is disabled, and no SKAS support is present on the host.\n");
 345                 exit(1);
 346         }
 347 #endif
 348         uml_start = CHOOSE_MODE_PROC(set_task_sizes_tt, set_task_sizes_skas, 0,
 349                                      &host_task_size, &task_size);
 350
 351         /* Need to check this early because mmapping happens before the
 352          * kernel is running.
 353          */
 354         check_tmpexec();
 355
 356         brk_start = (unsigned long) sbrk(0);
 357         CHOOSE_MODE_PROC(before_mem_tt, before_mem_skas, brk_start);
 358         /* Increase physical memory size for exec-shield users
 359         so they actually get what they asked for. This should
 360         add zero for non-exec shield users */
 361
 362         diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 363         if(diff > 1024 * 1024){
 364                 printf("Adding %ld bytes to physical memory to account for "
 365                        "exec-shield gap\n", diff);
 366                 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 367         }
 368
 369         uml_physmem = uml_start;
 370
 371         /* Reserve up to 4M after the current brk */
 372         uml_reserved = ROUND_4M(brk_start) + (1 << 22);
 373
 374         setup_machinename(system_utsname.machine);
 375
 376 #ifdef CONFIG_MODE_TT
 377         argv1_begin = argv[1];
 378         argv1_end = &argv[1][strlen(argv[1])];
 379 #endif
 380
 381         highmem = 0;
 382         iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
 383         max_physmem = get_kmem_end() - uml_physmem - iomem_size - MIN_VMALLOC;
 384
 385         /* Zones have to begin on a 1 << MAX_ORDER page boundary,
 386          * so this makes sure that's true for highmem
 387          */
 388         max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
 389         if(physmem_size + iomem_size > max_physmem){
 390                 highmem = physmem_size + iomem_size - max_physmem;
 391                 physmem_size -= highmem;
 392 #ifndef CONFIG_HIGHMEM
 393                 highmem = 0;
 394                 printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
 395                        "to %ld bytes\n", physmem_size);
 396 #endif
 397         }
 398
 399         high_physmem = uml_physmem + physmem_size;
 400         end_iomem = high_physmem + iomem_size;
 401         high_memory = (void *) end_iomem;
 402
 403         start_vm = VMALLOC_START;
 404
 405         setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
 406         if(init_maps(physmem_size, iomem_size, highmem)){
 407                 printf("Failed to allocate mem_map for %ld bytes of physical "
 408                        "memory and %ld bytes of highmem\n", physmem_size,
 409                        highmem);
 410                 exit(1);
 411         }
 412
 413         virtmem_size = physmem_size;
 414         avail = get_kmem_end() - start_vm;
 415         if(physmem_size > avail) virtmem_size = avail;
 416         end_vm = start_vm + virtmem_size;
 417
 418         if(virtmem_size < physmem_size)
 419                 printf("Kernel virtual memory size shrunk to %ld bytes\n",
 420                        virtmem_size);
 421
 422         uml_postsetup();
 423
 424         task_protections((unsigned long) &init_thread_info);
 425         os_flush_stdout();
 426
 427         return(CHOOSE_MODE(start_uml_tt(), start_uml_skas()));
 428 }
 429
 430 extern int uml_exitcode;
 431
 432 static int panic_exit(struct notifier_block *self, unsigned long unused1,
 433                       void *unused2)
 434 {
 435         bust_spinlocks(1);
 436         show_regs(&(current->thread.regs));
 437         bust_spinlocks(0);
 438         uml_exitcode = 1;
 439         machine_halt();
 440         return(0);
 441 }
 442
 443 static struct notifier_block panic_exit_notifier = {
 444         .notifier_call          = panic_exit,
 445         .next                   = NULL,
 446         .priority               = 0
 447 };
 448
 449 void __init setup_arch(char **cmdline_p)
 450 {
 451         notifier_chain_register(&panic_notifier_list, &panic_exit_notifier);
 452         paging_init();
 453         strlcpy(saved_command_line, command_line, COMMAND_LINE_SIZE);
 454         *cmdline_p = command_line;
 455         setup_hostinfo();
 456 }
 457
 458 void __init check_bugs(void)
 459 {
 460         arch_check_bugs();
 461         check_ptrace();
 462         check_sigio();
 463         check_devanon();
 464 }
 465
 466 void apply_alternatives(void *start, void *end)
 467 {
 468 }