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