arch/um/kernel/um_arch.c

   1 /*
   2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/delay.h>
   7 #include <linux/init.h>
   8 #include <linux/mm.h>
   9 #include <linux/module.h>
  10 #include <linux/seq_file.h>
  11 #include <linux/string.h>
  12 #include <linux/utsname.h>
  13 #include <linux/sched.h>
  14 #include <asm/pgtable.h>
  15 #include <asm/processor.h>
  16 #include <asm/setup.h>
  17 #include <as-layout.h>
  18 #include <arch.h>
  19 #include <init.h>
  20 #include <kern.h>
  21 #include <kern_util.h>
  22 #include <mem_user.h>
  23 #include <os.h>
  24
  25 #define DEFAULT_COMMAND_LINE "root=98:0"
  26
  27 /* Changed in add_arg and setup_arch, which run before SMP is started */
  28 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
  29
  30 static void __init add_arg(char *arg)
  31 {
  32         if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
  33                 printf("add_arg: Too many command line arguments!\n");
  34                 exit(1);
  35         }
  36         if (strlen(command_line) > 0)
  37                 strcat(command_line, " ");
  38         strcat(command_line, arg);
  39 }
  40
  41 /*
  42  * These fields are initialized at boot time and not changed.
  43  * XXX This structure is used only in the non-SMP case.  Maybe this
  44  * should be moved to smp.c.
  45  */
  46 struct cpuinfo_um boot_cpu_data = {
  47         .loops_per_jiffy        = 0,
  48         .ipi_pipe               = { -1, -1 }
  49 };
  50
  51 union thread_union cpu0_irqstack
  52         __attribute__((__section__(".data..init_irqstack"))) =
  53                 { INIT_THREAD_INFO(init_task) };
  54
  55 unsigned long thread_saved_pc(struct task_struct *task)
  56 {
  57         /* FIXME: Need to look up userspace_pid by cpu */
  58         return os_process_pc(userspace_pid[0]);
  59 }
  60
  61 /* Changed in setup_arch, which is called in early boot */
  62 static char host_info[(__NEW_UTS_LEN + 1) * 5];
  63
  64 static int show_cpuinfo(struct seq_file *m, void *v)
  65 {
  66         int index = 0;
  67
  68 #ifdef CONFIG_SMP
  69         index = (struct cpuinfo_um *) v - cpu_data;
  70         if (!cpu_online(index))
  71                 return 0;
  72 #endif
  73
  74         seq_printf(m, "processor\t: %d\n", index);
  75         seq_printf(m, "vendor_id\t: User Mode Linux\n");
  76         seq_printf(m, "model name\t: UML\n");
  77         seq_printf(m, "mode\t\t: skas\n");
  78         seq_printf(m, "host\t\t: %s\n", host_info);
  79         seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
  80                    loops_per_jiffy/(500000/HZ),
  81                    (loops_per_jiffy/(5000/HZ)) % 100);
  82
  83         return 0;
  84 }
  85
  86 static void *c_start(struct seq_file *m, loff_t *pos)
  87 {
  88         return *pos < NR_CPUS ? cpu_data + *pos : NULL;
  89 }
  90
  91 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
  92 {
  93         ++*pos;
  94         return c_start(m, pos);
  95 }
  96
  97 static void c_stop(struct seq_file *m, void *v)
  98 {
  99 }
 100
 101 const struct seq_operations cpuinfo_op = {
 102         .start  = c_start,
 103         .next   = c_next,
 104         .stop   = c_stop,
 105         .show   = show_cpuinfo,
 106 };
 107
 108 /* Set in linux_main */
 109 unsigned long uml_physmem;
 110 EXPORT_SYMBOL(uml_physmem);
 111
 112 unsigned long uml_reserved; /* Also modified in mem_init */
 113 unsigned long start_vm;
 114 unsigned long end_vm;
 115
 116 /* Set in uml_ncpus_setup */
 117 int ncpus = 1;
 118
 119 /* Set in early boot */
 120 static int have_root __initdata = 0;
 121
 122 /* Set in uml_mem_setup and modified in linux_main */
 123 long long physmem_size = 32 * 1024 * 1024;
 124
 125 static const char *usage_string =
 126 "User Mode Linux v%s\n"
 127 "       available at http://user-mode-linux.sourceforge.net/\n\n";
 128
 129 static int __init uml_version_setup(char *line, int *add)
 130 {
 131         printf("%s\n", init_utsname()->release);
 132         exit(0);
 133
 134         return 0;
 135 }
 136
 137 __uml_setup("--version", uml_version_setup,
 138 "--version\n"
 139 "    Prints the version number of the kernel.\n\n"
 140 );
 141
 142 static int __init uml_root_setup(char *line, int *add)
 143 {
 144         have_root = 1;
 145         return 0;
 146 }
 147
 148 __uml_setup("root=", uml_root_setup,
 149 "root=<file containing the root fs>\n"
 150 "    This is actually used by the generic kernel in exactly the same\n"
 151 "    way as in any other kernel. If you configure a number of block\n"
 152 "    devices and want to boot off something other than ubd0, you \n"
 153 "    would use something like:\n"
 154 "        root=/dev/ubd5\n\n"
 155 );
 156
 157 static int __init no_skas_debug_setup(char *line, int *add)
 158 {
 159         printf("'debug' is not necessary to gdb UML in skas mode - run \n");
 160         printf("'gdb linux'\n");
 161
 162         return 0;
 163 }
 164
 165 __uml_setup("debug", no_skas_debug_setup,
 166 "debug\n"
 167 "    this flag is not needed to run gdb on UML in skas mode\n\n"
 168 );
 169
 170 #ifdef CONFIG_SMP
 171 static int __init uml_ncpus_setup(char *line, int *add)
 172 {
 173         if (!sscanf(line, "%d", &ncpus)) {
 174                 printf("Couldn't parse [%s]\n", line);
 175                 return -1;
 176         }
 177
 178         return 0;
 179 }
 180
 181 __uml_setup("ncpus=", uml_ncpus_setup,
 182 "ncpus=<# of desired CPUs>\n"
 183 "    This tells an SMP kernel how many virtual processors to start.\n\n"
 184 );
 185 #endif
 186
 187 static int __init Usage(char *line, int *add)
 188 {
 189         const char **p;
 190
 191         printf(usage_string, init_utsname()->release);
 192         p = &__uml_help_start;
 193         while (p < &__uml_help_end) {
 194                 printf("%s", *p);
 195                 p++;
 196         }
 197         exit(0);
 198         return 0;
 199 }
 200
 201 __uml_setup("--help", Usage,
 202 "--help\n"
 203 "    Prints this message.\n\n"
 204 );
 205
 206 static void __init uml_checksetup(char *line, int *add)
 207 {
 208         struct uml_param *p;
 209
 210         p = &__uml_setup_start;
 211         while (p < &__uml_setup_end) {
 212                 size_t n;
 213
 214                 n = strlen(p->str);
 215                 if (!strncmp(line, p->str, n) && p->setup_func(line + n, add))
 216                         return;
 217                 p++;
 218         }
 219 }
 220
 221 static void __init uml_postsetup(void)
 222 {
 223         initcall_t *p;
 224
 225         p = &__uml_postsetup_start;
 226         while (p < &__uml_postsetup_end) {
 227                 (*p)();
 228                 p++;
 229         }
 230         return;
 231 }
 232
 233 static int panic_exit(struct notifier_block *self, unsigned long unused1,
 234                       void *unused2)
 235 {
 236         bust_spinlocks(1);
 237         show_regs(&(current->thread.regs));
 238         bust_spinlocks(0);
 239         uml_exitcode = 1;
 240         os_dump_core();
 241         return 0;
 242 }
 243
 244 static struct notifier_block panic_exit_notifier = {
 245         .notifier_call          = panic_exit,
 246         .next                   = NULL,
 247         .priority               = 0
 248 };
 249
 250 /* Set during early boot */
 251 unsigned long task_size;
 252 EXPORT_SYMBOL(task_size);
 253
 254 unsigned long host_task_size;
 255
 256 unsigned long brk_start;
 257 unsigned long end_iomem;
 258 EXPORT_SYMBOL(end_iomem);
 259
 260 #define MIN_VMALLOC (32 * 1024 * 1024)
 261
 262 extern char __binary_start;
 263
 264 int __init linux_main(int argc, char **argv)
 265 {
 266         unsigned long avail, diff;
 267         unsigned long virtmem_size, max_physmem;
 268         unsigned long stack;
 269         unsigned int i;
 270         int add;
 271         char * mode;
 272
 273         for (i = 1; i < argc; i++) {
 274                 if ((i == 1) && (argv[i][0] == ' '))
 275                         continue;
 276                 add = 1;
 277                 uml_checksetup(argv[i], &add);
 278                 if (add)
 279                         add_arg(argv[i]);
 280         }
 281         if (have_root == 0)
 282                 add_arg(DEFAULT_COMMAND_LINE);
 283
 284         host_task_size = os_get_top_address();
 285         /*
 286          * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps
 287          * out
 288          */
 289         task_size = host_task_size & PGDIR_MASK;
 290
 291         /* OS sanity checks that need to happen before the kernel runs */
 292         os_early_checks();
 293
 294         can_do_skas();
 295
 296         if (proc_mm && ptrace_faultinfo)
 297                 mode = "SKAS3";
 298         else
 299                 mode = "SKAS0";
 300
 301         printf("UML running in %s mode\n", mode);
 302
 303         brk_start = (unsigned long) sbrk(0);
 304
 305         /*
 306          * Increase physical memory size for exec-shield users
 307          * so they actually get what they asked for. This should
 308          * add zero for non-exec shield users
 309          */
 310
 311         diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 312         if (diff > 1024 * 1024) {
 313                 printf("Adding %ld bytes to physical memory to account for "
 314                        "exec-shield gap\n", diff);
 315                 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 316         }
 317
 318         uml_physmem = (unsigned long) &__binary_start & PAGE_MASK;
 319
 320         /* Reserve up to 4M after the current brk */
 321         uml_reserved = ROUND_4M(brk_start) + (1 << 22);
 322
 323         setup_machinename(init_utsname()->machine);
 324
 325         highmem = 0;
 326         iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
 327         max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
 328
 329         /*
 330          * Zones have to begin on a 1 << MAX_ORDER page boundary,
 331          * so this makes sure that's true for highmem
 332          */
 333         max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
 334         if (physmem_size + iomem_size > max_physmem) {
 335                 highmem = physmem_size + iomem_size - max_physmem;
 336                 physmem_size -= highmem;
 337 #ifndef CONFIG_HIGHMEM
 338                 highmem = 0;
 339                 printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
 340                        "to %Lu bytes\n", physmem_size);
 341 #endif
 342         }
 343
 344         high_physmem = uml_physmem + physmem_size;
 345         end_iomem = high_physmem + iomem_size;
 346         high_memory = (void *) end_iomem;
 347
 348         start_vm = VMALLOC_START;
 349
 350         setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
 351         if (init_maps(physmem_size, iomem_size, highmem)) {
 352                 printf("Failed to allocate mem_map for %Lu bytes of physical "
 353                        "memory and %Lu bytes of highmem\n", physmem_size,
 354                        highmem);
 355                 exit(1);
 356         }
 357
 358         virtmem_size = physmem_size;
 359         stack = (unsigned long) argv;
 360         stack &= ~(1024 * 1024 - 1);
 361         avail = stack - start_vm;
 362         if (physmem_size > avail)
 363                 virtmem_size = avail;
 364         end_vm = start_vm + virtmem_size;
 365
 366         if (virtmem_size < physmem_size)
 367                 printf("Kernel virtual memory size shrunk to %lu bytes\n",
 368                        virtmem_size);
 369
 370         atomic_notifier_chain_register(&panic_notifier_list,
 371                                        &panic_exit_notifier);
 372
 373         uml_postsetup();
 374
 375         stack_protections((unsigned long) &init_thread_info);
 376         os_flush_stdout();
 377
 378         return start_uml();
 379 }
 380
 381 void __init setup_arch(char **cmdline_p)
 382 {
 383         paging_init();
 384         strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 385         *cmdline_p = command_line;
 386         setup_hostinfo(host_info, sizeof host_info);
 387 }
 388
 389 void __init check_bugs(void)
 390 {
 391         arch_check_bugs();
 392         os_check_bugs();
 393 }
 394
 395 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 396 {
 397 }
 398
 399 #ifdef CONFIG_SMP
 400 void alternatives_smp_module_add(struct module *mod, char *name,
 401                                  void *locks, void *locks_end,
 402                                  void *text,  void *text_end)
 403 {
 404 }
 405
 406 void alternatives_smp_module_del(struct module *mod)
 407 {
 408 }
 409 #endif