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