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