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