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 EXPORT_SYMBOL(uml_physmem);
 106
 107 unsigned long uml_reserved; /* Also modified in mem_init */
 108 unsigned long start_vm;
 109 unsigned long end_vm;
 110
 111 /* Set in uml_ncpus_setup */
 112 int ncpus = 1;
 113
 114 /* Set in early boot */
 115 static int have_root __initdata = 0;
 116
 117 /* Set in uml_mem_setup and modified in linux_main */
 118 long long physmem_size = 32 * 1024 * 1024;
 119
 120 static const char *usage_string =
 121 "User Mode Linux v%s\n"
 122 "       available at http://user-mode-linux.sourceforge.net/\n\n";
 123
 124 static int __init uml_version_setup(char *line, int *add)
 125 {
 126         printf("%s\n", init_utsname()->release);
 127         exit(0);
 128
 129         return 0;
 130 }
 131
 132 __uml_setup("--version", uml_version_setup,
 133 "--version\n"
 134 "    Prints the version number of the kernel.\n\n"
 135 );
 136
 137 static int __init uml_root_setup(char *line, int *add)
 138 {
 139         have_root = 1;
 140         return 0;
 141 }
 142
 143 __uml_setup("root=", uml_root_setup,
 144 "root=<file containing the root fs>\n"
 145 "    This is actually used by the generic kernel in exactly the same\n"
 146 "    way as in any other kernel. If you configure a number of block\n"
 147 "    devices and want to boot off something other than ubd0, you \n"
 148 "    would use something like:\n"
 149 "        root=/dev/ubd5\n\n"
 150 );
 151
 152 static int __init no_skas_debug_setup(char *line, int *add)
 153 {
 154         printf("'debug' is not necessary to gdb UML in skas mode - run \n");
 155         printf("'gdb linux'\n");
 156
 157         return 0;
 158 }
 159
 160 __uml_setup("debug", no_skas_debug_setup,
 161 "debug\n"
 162 "    this flag is not needed to run gdb on UML in skas mode\n\n"
 163 );
 164
 165 #ifdef CONFIG_SMP
 166 static int __init uml_ncpus_setup(char *line, int *add)
 167 {
 168         if (!sscanf(line, "%d", &ncpus)) {
 169                 printf("Couldn't parse [%s]\n", line);
 170                 return -1;
 171         }
 172
 173         return 0;
 174 }
 175
 176 __uml_setup("ncpus=", uml_ncpus_setup,
 177 "ncpus=<# of desired CPUs>\n"
 178 "    This tells an SMP kernel how many virtual processors to start.\n\n"
 179 );
 180 #endif
 181
 182 static int __init Usage(char *line, int *add)
 183 {
 184         const char **p;
 185
 186         printf(usage_string, init_utsname()->release);
 187         p = &__uml_help_start;
 188         while (p < &__uml_help_end) {
 189                 printf("%s", *p);
 190                 p++;
 191         }
 192         exit(0);
 193         return 0;
 194 }
 195
 196 __uml_setup("--help", Usage,
 197 "--help\n"
 198 "    Prints this message.\n\n"
 199 );
 200
 201 static void __init uml_checksetup(char *line, int *add)
 202 {
 203         struct uml_param *p;
 204
 205         p = &__uml_setup_start;
 206         while (p < &__uml_setup_end) {
 207                 size_t n;
 208
 209                 n = strlen(p->str);
 210                 if (!strncmp(line, p->str, n) && p->setup_func(line + n, add))
 211                         return;
 212                 p++;
 213         }
 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 static int panic_exit(struct notifier_block *self, unsigned long unused1,
 229                       void *unused2)
 230 {
 231         bust_spinlocks(1);
 232         show_regs(&(current->thread.regs));
 233         bust_spinlocks(0);
 234         uml_exitcode = 1;
 235         os_dump_core();
 236         return 0;
 237 }
 238
 239 static struct notifier_block panic_exit_notifier = {
 240         .notifier_call          = panic_exit,
 241         .next                   = NULL,
 242         .priority               = 0
 243 };
 244
 245 /* Set during early boot */
 246 unsigned long task_size;
 247 EXPORT_SYMBOL(task_size);
 248
 249 unsigned long host_task_size;
 250
 251 unsigned long brk_start;
 252 unsigned long end_iomem;
 253 EXPORT_SYMBOL(end_iomem);
 254
 255 #define MIN_VMALLOC (32 * 1024 * 1024)
 256
 257 extern char __binary_start;
 258
 259 int __init linux_main(int argc, char **argv)
 260 {
 261         unsigned long avail, diff;
 262         unsigned long virtmem_size, max_physmem;
 263         unsigned long stack;
 264         unsigned int i;
 265         int add;
 266         char * mode;
 267
 268         for (i = 1; i < argc; i++) {
 269                 if ((i == 1) && (argv[i][0] == ' '))
 270                         continue;
 271                 add = 1;
 272                 uml_checksetup(argv[i], &add);
 273                 if (add)
 274                         add_arg(argv[i]);
 275         }
 276         if (have_root == 0)
 277                 add_arg(DEFAULT_COMMAND_LINE);
 278
 279         host_task_size = os_get_top_address();
 280         /*
 281          * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps
 282          * out
 283          */
 284         task_size = host_task_size & PGDIR_MASK;
 285
 286         /* OS sanity checks that need to happen before the kernel runs */
 287         os_early_checks();
 288
 289         can_do_skas();
 290
 291         if (proc_mm && ptrace_faultinfo)
 292                 mode = "SKAS3";
 293         else
 294                 mode = "SKAS0";
 295
 296         printf("UML running in %s mode\n", mode);
 297
 298         brk_start = (unsigned long) sbrk(0);
 299
 300         /*
 301          * Increase physical memory size for exec-shield users
 302          * so they actually get what they asked for. This should
 303          * add zero for non-exec shield users
 304          */
 305
 306         diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 307         if (diff > 1024 * 1024) {
 308                 printf("Adding %ld bytes to physical memory to account for "
 309                        "exec-shield gap\n", diff);
 310                 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 311         }
 312
 313         uml_physmem = (unsigned long) &__binary_start & PAGE_MASK;
 314
 315         /* Reserve up to 4M after the current brk */
 316         uml_reserved = ROUND_4M(brk_start) + (1 << 22);
 317
 318         setup_machinename(init_utsname()->machine);
 319
 320         highmem = 0;
 321         iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
 322         max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
 323
 324         /*
 325          * Zones have to begin on a 1 << MAX_ORDER page boundary,
 326          * so this makes sure that's true for highmem
 327          */
 328         max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
 329         if (physmem_size + iomem_size > max_physmem) {
 330                 highmem = physmem_size + iomem_size - max_physmem;
 331                 physmem_size -= highmem;
 332 #ifndef CONFIG_HIGHMEM
 333                 highmem = 0;
 334                 printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
 335                        "to %Lu bytes\n", physmem_size);
 336 #endif
 337         }
 338
 339         high_physmem = uml_physmem + physmem_size;
 340         end_iomem = high_physmem + iomem_size;
 341         high_memory = (void *) end_iomem;
 342
 343         start_vm = VMALLOC_START;
 344
 345         setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
 346         if (init_maps(physmem_size, iomem_size, highmem)) {
 347                 printf("Failed to allocate mem_map for %Lu bytes of physical "
 348                        "memory and %Lu bytes of highmem\n", physmem_size,
 349                        highmem);
 350                 exit(1);
 351         }
 352
 353         virtmem_size = physmem_size;
 354         stack = (unsigned long) argv;
 355         stack &= ~(1024 * 1024 - 1);
 356         avail = stack - start_vm;
 357         if (physmem_size > avail)
 358                 virtmem_size = avail;
 359         end_vm = start_vm + virtmem_size;
 360
 361         if (virtmem_size < physmem_size)
 362                 printf("Kernel virtual memory size shrunk to %lu bytes\n",
 363                        virtmem_size);
 364
 365         atomic_notifier_chain_register(&panic_notifier_list,
 366                                        &panic_exit_notifier);
 367
 368         uml_postsetup();
 369
 370         stack_protections((unsigned long) &init_thread_info);
 371         os_flush_stdout();
 372
 373         return start_uml();
 374 }
 375
 376 void __init setup_arch(char **cmdline_p)
 377 {
 378         paging_init();
 379         strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 380         *cmdline_p = command_line;
 381         setup_hostinfo(host_info, sizeof host_info);
 382 }
 383
 384 void __init check_bugs(void)
 385 {
 386         arch_check_bugs();
 387         os_check_bugs();
 388 }
 389
 390 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 391 {
 392 }
 393
 394 #ifdef CONFIG_SMP
 395 void alternatives_smp_module_add(struct module *mod, char *name,
 396                                  void *locks, void *locks_end,
 397                                  void *text,  void *text_end)
 398 {
 399 }
 400
 401 void alternatives_smp_module_del(struct module *mod)
 402 {
 403 }
 404 #endif