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