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/kmsg_dump.h>
  15 #include <asm/pgtable.h>
  16 #include <asm/processor.h>
  17 #include <asm/sections.h>
  18 #include <asm/setup.h>
  19 #include <as-layout.h>
  20 #include <arch.h>
  21 #include <init.h>
  22 #include <kern.h>
  23 #include <kern_util.h>
  24 #include <mem_user.h>
  25 #include <os.h>
  26
  27 #define DEFAULT_COMMAND_LINE "root=98:0"
  28
  29 /* Changed in add_arg and setup_arch, which run before SMP is started */
  30 static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
  31
  32 static void __init add_arg(char *arg)
  33 {
  34         if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
  35                 printf("add_arg: Too many command line arguments!\n");
  36                 exit(1);
  37         }
  38         if (strlen(command_line) > 0)
  39                 strcat(command_line, " ");
  40         strcat(command_line, arg);
  41 }
  42
  43 /*
  44  * These fields are initialized at boot time and not changed.
  45  * XXX This structure is used only in the non-SMP case.  Maybe this
  46  * should be moved to smp.c.
  47  */
  48 struct cpuinfo_um boot_cpu_data = {
  49         .loops_per_jiffy        = 0,
  50         .ipi_pipe               = { -1, -1 }
  51 };
  52
  53 union thread_union cpu0_irqstack
  54         __attribute__((__section__(".data..init_irqstack"))) =
  55                 { INIT_THREAD_INFO(init_task) };
  56
  57 unsigned long thread_saved_pc(struct task_struct *task)
  58 {
  59         /* FIXME: Need to look up userspace_pid by cpu */
  60         return os_process_pc(userspace_pid[0]);
  61 }
  62
  63 /* Changed in setup_arch, which is called in early boot */
  64 static char host_info[(__NEW_UTS_LEN + 1) * 5];
  65
  66 static int show_cpuinfo(struct seq_file *m, void *v)
  67 {
  68         int index = 0;
  69
  70         seq_printf(m, "processor\t: %d\n", index);
  71         seq_printf(m, "vendor_id\t: User Mode Linux\n");
  72         seq_printf(m, "model name\t: UML\n");
  73         seq_printf(m, "mode\t\t: skas\n");
  74         seq_printf(m, "host\t\t: %s\n", host_info);
  75         seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
  76                    loops_per_jiffy/(500000/HZ),
  77                    (loops_per_jiffy/(5000/HZ)) % 100);
  78
  79         return 0;
  80 }
  81
  82 static void *c_start(struct seq_file *m, loff_t *pos)
  83 {
  84         return *pos < NR_CPUS ? cpu_data + *pos : NULL;
  85 }
  86
  87 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
  88 {
  89         ++*pos;
  90         return c_start(m, pos);
  91 }
  92
  93 static void c_stop(struct seq_file *m, void *v)
  94 {
  95 }
  96
  97 const struct seq_operations cpuinfo_op = {
  98         .start  = c_start,
  99         .next   = c_next,
 100         .stop   = c_stop,
 101         .show   = show_cpuinfo,
 102 };
 103
 104 /* Set in linux_main */
 105 unsigned long uml_physmem;
 106 EXPORT_SYMBOL(uml_physmem);
 107
 108 unsigned long uml_reserved; /* Also modified in mem_init */
 109 unsigned long start_vm;
 110 unsigned long end_vm;
 111
 112 /* Set in uml_ncpus_setup */
 113 int ncpus = 1;
 114
 115 /* Set in early boot */
 116 static int have_root __initdata = 0;
 117
 118 /* Set in uml_mem_setup and modified in linux_main */
 119 long long physmem_size = 32 * 1024 * 1024;
 120
 121 static const char *usage_string =
 122 "User Mode Linux v%s\n"
 123 "       available at http://user-mode-linux.sourceforge.net/\n\n";
 124
 125 static int __init uml_version_setup(char *line, int *add)
 126 {
 127         printf("%s\n", init_utsname()->release);
 128         exit(0);
 129
 130         return 0;
 131 }
 132
 133 __uml_setup("--version", uml_version_setup,
 134 "--version\n"
 135 "    Prints the version number of the kernel.\n\n"
 136 );
 137
 138 static int __init uml_root_setup(char *line, int *add)
 139 {
 140         have_root = 1;
 141         return 0;
 142 }
 143
 144 __uml_setup("root=", uml_root_setup,
 145 "root=<file containing the root fs>\n"
 146 "    This is actually used by the generic kernel in exactly the same\n"
 147 "    way as in any other kernel. If you configure a number of block\n"
 148 "    devices and want to boot off something other than ubd0, you \n"
 149 "    would use something like:\n"
 150 "        root=/dev/ubd5\n\n"
 151 );
 152
 153 static int __init no_skas_debug_setup(char *line, int *add)
 154 {
 155         printf("'debug' is not necessary to gdb UML in skas mode - run \n");
 156         printf("'gdb linux'\n");
 157
 158         return 0;
 159 }
 160
 161 __uml_setup("debug", no_skas_debug_setup,
 162 "debug\n"
 163 "    this flag is not needed to run gdb on UML in skas mode\n\n"
 164 );
 165
 166 static int __init Usage(char *line, int *add)
 167 {
 168         const char **p;
 169
 170         printf(usage_string, init_utsname()->release);
 171         p = &__uml_help_start;
 172         while (p < &__uml_help_end) {
 173                 printf("%s", *p);
 174                 p++;
 175         }
 176         exit(0);
 177         return 0;
 178 }
 179
 180 __uml_setup("--help", Usage,
 181 "--help\n"
 182 "    Prints this message.\n\n"
 183 );
 184
 185 static void __init uml_checksetup(char *line, int *add)
 186 {
 187         struct uml_param *p;
 188
 189         p = &__uml_setup_start;
 190         while (p < &__uml_setup_end) {
 191                 size_t n;
 192
 193                 n = strlen(p->str);
 194                 if (!strncmp(line, p->str, n) && p->setup_func(line + n, add))
 195                         return;
 196                 p++;
 197         }
 198 }
 199
 200 static void __init uml_postsetup(void)
 201 {
 202         initcall_t *p;
 203
 204         p = &__uml_postsetup_start;
 205         while (p < &__uml_postsetup_end) {
 206                 (*p)();
 207                 p++;
 208         }
 209         return;
 210 }
 211
 212 static int panic_exit(struct notifier_block *self, unsigned long unused1,
 213                       void *unused2)
 214 {
 215         kmsg_dump(KMSG_DUMP_PANIC);
 216         bust_spinlocks(1);
 217         bust_spinlocks(0);
 218         uml_exitcode = 1;
 219         os_dump_core();
 220         return 0;
 221 }
 222
 223 static struct notifier_block panic_exit_notifier = {
 224         .notifier_call          = panic_exit,
 225         .next                   = NULL,
 226         .priority               = 0
 227 };
 228
 229 void uml_finishsetup(void)
 230 {
 231         atomic_notifier_chain_register(&panic_notifier_list,
 232                                        &panic_exit_notifier);
 233
 234         uml_postsetup();
 235
 236         new_thread_handler();
 237 }
 238
 239 /* Set during early boot */
 240 unsigned long task_size;
 241 EXPORT_SYMBOL(task_size);
 242
 243 unsigned long host_task_size;
 244
 245 unsigned long brk_start;
 246 unsigned long end_iomem;
 247 EXPORT_SYMBOL(end_iomem);
 248
 249 #define MIN_VMALLOC (32 * 1024 * 1024)
 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 long stack;
 256         unsigned int i;
 257         int add;
 258
 259         for (i = 1; i < argc; i++) {
 260                 if ((i == 1) && (argv[i][0] == ' '))
 261                         continue;
 262                 add = 1;
 263                 uml_checksetup(argv[i], &add);
 264                 if (add)
 265                         add_arg(argv[i]);
 266         }
 267         if (have_root == 0)
 268                 add_arg(DEFAULT_COMMAND_LINE);
 269
 270         host_task_size = os_get_top_address();
 271         /*
 272          * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps
 273          * out
 274          */
 275         task_size = host_task_size & PGDIR_MASK;
 276
 277         /* OS sanity checks that need to happen before the kernel runs */
 278         os_early_checks();
 279
 280         brk_start = (unsigned long) sbrk(0);
 281
 282         /*
 283          * Increase physical memory size for exec-shield users
 284          * so they actually get what they asked for. This should
 285          * add zero for non-exec shield users
 286          */
 287
 288         diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 289         if (diff > 1024 * 1024) {
 290                 printf("Adding %ld bytes to physical memory to account for "
 291                        "exec-shield gap\n", diff);
 292                 physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 293         }
 294
 295         uml_physmem = (unsigned long) __binary_start & PAGE_MASK;
 296
 297         /* Reserve up to 4M after the current brk */
 298         uml_reserved = ROUND_4M(brk_start) + (1 << 22);
 299
 300         setup_machinename(init_utsname()->machine);
 301
 302         highmem = 0;
 303         iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
 304         max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
 305
 306         /*
 307          * Zones have to begin on a 1 << MAX_ORDER page boundary,
 308          * so this makes sure that's true for highmem
 309          */
 310         max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
 311         if (physmem_size + iomem_size > max_physmem) {
 312                 highmem = physmem_size + iomem_size - max_physmem;
 313                 physmem_size -= highmem;
 314         }
 315
 316         high_physmem = uml_physmem + physmem_size;
 317         end_iomem = high_physmem + iomem_size;
 318         high_memory = (void *) end_iomem;
 319
 320         start_vm = VMALLOC_START;
 321
 322         virtmem_size = physmem_size;
 323         stack = (unsigned long) argv;
 324         stack &= ~(1024 * 1024 - 1);
 325         avail = stack - start_vm;
 326         if (physmem_size > avail)
 327                 virtmem_size = avail;
 328         end_vm = start_vm + virtmem_size;
 329
 330         if (virtmem_size < physmem_size)
 331                 printf("Kernel virtual memory size shrunk to %lu bytes\n",
 332                        virtmem_size);
 333
 334         os_flush_stdout();
 335
 336         return start_uml();
 337 }
 338
 339 void __init setup_arch(char **cmdline_p)
 340 {
 341         stack_protections((unsigned long) &init_thread_info);
 342         setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
 343         mem_total_pages(physmem_size, iomem_size, highmem);
 344
 345         paging_init();
 346         strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 347         *cmdline_p = command_line;
 348         setup_hostinfo(host_info, sizeof host_info);
 349 }
 350
 351 void __init check_bugs(void)
 352 {
 353         arch_check_bugs();
 354         os_check_bugs();
 355 }
 356
 357 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 358 {
 359 }