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 /* Changed in setup_arch, which is called in early boot */
  60 static char host_info[(__NEW_UTS_LEN + 1) * 5];
  61
  62 static int show_cpuinfo(struct seq_file *m, void *v)
  63 {
  64         int index = 0;
  65
  66         seq_printf(m, "processor\t: %d\n", index);
  67         seq_printf(m, "vendor_id\t: User Mode Linux\n");
  68         seq_printf(m, "model name\t: UML\n");
  69         seq_printf(m, "mode\t\t: skas\n");
  70         seq_printf(m, "host\t\t: %s\n", host_info);
  71         seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
  72                    loops_per_jiffy/(500000/HZ),
  73                    (loops_per_jiffy/(5000/HZ)) % 100);
  74
  75         return 0;
  76 }
  77
  78 static void *c_start(struct seq_file *m, loff_t *pos)
  79 {
  80         return *pos < NR_CPUS ? cpu_data + *pos : NULL;
  81 }
  82
  83 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
  84 {
  85         ++*pos;
  86         return c_start(m, pos);
  87 }
  88
  89 static void c_stop(struct seq_file *m, void *v)
  90 {
  91 }
  92
  93 const struct seq_operations cpuinfo_op = {
  94         .start  = c_start,
  95         .next   = c_next,
  96         .stop   = c_stop,
  97         .show   = show_cpuinfo,
  98 };
  99
 100 /* Set in linux_main */
 101 unsigned long uml_physmem;
 102 EXPORT_SYMBOL(uml_physmem);
 103
 104 unsigned long uml_reserved; /* Also modified in mem_init */
 105 unsigned long start_vm;
 106 unsigned long end_vm;
 107
 108 /* Set in uml_ncpus_setup */
 109 int ncpus = 1;
 110
 111 /* Set in early boot */
 112 static int have_root __initdata = 0;
 113
 114 /* Set in uml_mem_setup and modified in linux_main */
 115 long long physmem_size = 32 * 1024 * 1024;
 116
 117 static const char *usage_string =
 118 "User Mode Linux v%s\n"
 119 "       available at http://user-mode-linux.sourceforge.net/\n\n";
 120
 121 static int __init uml_version_setup(char *line, int *add)
 122 {
 123         /* Explicitly use printf() to show version in stdout */
 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         os_warn("'debug' is not necessary to gdb UML in skas mode - run\n");
 153         os_warn("'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 static int __init Usage(char *line, int *add)
 164 {
 165         const char **p;
 166
 167         printf(usage_string, init_utsname()->release);
 168         p = &__uml_help_start;
 169         /* Explicitly use printf() to show help in stdout */
 170         while (p < &__uml_help_end) {
 171                 printf("%s", *p);
 172                 p++;
 173         }
 174         exit(0);
 175         return 0;
 176 }
 177
 178 __uml_setup("--help", Usage,
 179 "--help\n"
 180 "    Prints this message.\n\n"
 181 );
 182
 183 static void __init uml_checksetup(char *line, int *add)
 184 {
 185         struct uml_param *p;
 186
 187         p = &__uml_setup_start;
 188         while (p < &__uml_setup_end) {
 189                 size_t n;
 190
 191                 n = strlen(p->str);
 192                 if (!strncmp(line, p->str, n) && p->setup_func(line + n, add))
 193                         return;
 194                 p++;
 195         }
 196 }
 197
 198 static void __init uml_postsetup(void)
 199 {
 200         initcall_t *p;
 201
 202         p = &__uml_postsetup_start;
 203         while (p < &__uml_postsetup_end) {
 204                 (*p)();
 205                 p++;
 206         }
 207         return;
 208 }
 209
 210 static int panic_exit(struct notifier_block *self, unsigned long unused1,
 211                       void *unused2)
 212 {
 213         kmsg_dump(KMSG_DUMP_PANIC);
 214         bust_spinlocks(1);
 215         bust_spinlocks(0);
 216         uml_exitcode = 1;
 217         os_dump_core();
 218         return 0;
 219 }
 220
 221 static struct notifier_block panic_exit_notifier = {
 222         .notifier_call          = panic_exit,
 223         .next                   = NULL,
 224         .priority               = 0
 225 };
 226
 227 void uml_finishsetup(void)
 228 {
 229         atomic_notifier_chain_register(&panic_notifier_list,
 230                                        &panic_exit_notifier);
 231
 232         uml_postsetup();
 233
 234         new_thread_handler();
 235 }
 236
 237 /* Set during early boot */
 238 unsigned long task_size;
 239 EXPORT_SYMBOL(task_size);
 240
 241 unsigned long host_task_size;
 242
 243 unsigned long brk_start;
 244 unsigned long end_iomem;
 245 EXPORT_SYMBOL(end_iomem);
 246
 247 #define MIN_VMALLOC (32 * 1024 * 1024)
 248
 249 int __init linux_main(int argc, char **argv)
 250 {
 251         unsigned long avail, diff;
 252         unsigned long virtmem_size, max_physmem;
 253         unsigned long stack;
 254         unsigned int i;
 255         int add;
 256
 257         for (i = 1; i < argc; i++) {
 258                 if ((i == 1) && (argv[i][0] == ' '))
 259                         continue;
 260                 add = 1;
 261                 uml_checksetup(argv[i], &add);
 262                 if (add)
 263                         add_arg(argv[i]);
 264         }
 265         if (have_root == 0)
 266                 add_arg(DEFAULT_COMMAND_LINE);
 267
 268         host_task_size = os_get_top_address();
 269         /*
 270          * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps
 271          * out
 272          */
 273         task_size = host_task_size & PGDIR_MASK;
 274
 275         /* OS sanity checks that need to happen before the kernel runs */
 276         os_early_checks();
 277
 278         brk_start = (unsigned long) sbrk(0);
 279
 280         /*
 281          * Increase physical memory size for exec-shield users
 282          * so they actually get what they asked for. This should
 283          * add zero for non-exec shield users
 284          */
 285
 286         diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 287         if (diff > 1024 * 1024) {
 288                 os_info("Adding %ld bytes to physical memory to account for "
 289                         "exec-shield gap\n", diff);
 290                 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 291         }
 292
 293         uml_physmem = (unsigned long) __binary_start & PAGE_MASK;
 294
 295         /* Reserve up to 4M after the current brk */
 296         uml_reserved = ROUND_4M(brk_start) + (1 << 22);
 297
 298         setup_machinename(init_utsname()->machine);
 299
 300         highmem = 0;
 301         iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
 302         max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
 303
 304         /*
 305          * Zones have to begin on a 1 << MAX_ORDER page boundary,
 306          * so this makes sure that's true for highmem
 307          */
 308         max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
 309         if (physmem_size + iomem_size > max_physmem) {
 310                 highmem = physmem_size + iomem_size - max_physmem;
 311                 physmem_size -= highmem;
 312         }
 313
 314         high_physmem = uml_physmem + physmem_size;
 315         end_iomem = high_physmem + iomem_size;
 316         high_memory = (void *) end_iomem;
 317
 318         start_vm = VMALLOC_START;
 319
 320         virtmem_size = physmem_size;
 321         stack = (unsigned long) argv;
 322         stack &= ~(1024 * 1024 - 1);
 323         avail = stack - start_vm;
 324         if (physmem_size > avail)
 325                 virtmem_size = avail;
 326         end_vm = start_vm + virtmem_size;
 327
 328         if (virtmem_size < physmem_size)
 329                 os_info("Kernel virtual memory size shrunk to %lu bytes\n",
 330                         virtmem_size);
 331
 332         os_flush_stdout();
 333
 334         return start_uml();
 335 }
 336
 337 int __init __weak read_initrd(void)
 338 {
 339         return 0;
 340 }
 341
 342 void __init setup_arch(char **cmdline_p)
 343 {
 344         stack_protections((unsigned long) &init_thread_info);
 345         setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
 346         mem_total_pages(physmem_size, iomem_size, highmem);
 347         read_initrd();
 348
 349         paging_init();
 350         strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 351         *cmdline_p = command_line;
 352         setup_hostinfo(host_info, sizeof host_info);
 353 }
 354
 355 void __init check_bugs(void)
 356 {
 357         arch_check_bugs();
 358         os_check_bugs();
 359 }
 360
 361 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 362 {
 363 }