linux/arch/um/kernel/um_arch.c
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   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 */
  27static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
  28
  29static 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 */
  45struct cpuinfo_um boot_cpu_data = {
  46        .loops_per_jiffy        = 0,
  47        .ipi_pipe               = { -1, -1 }
  48};
  49
  50unsigned 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 */
  57static char host_info[(__NEW_UTS_LEN + 1) * 5];
  58
  59static 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
  81static void *c_start(struct seq_file *m, loff_t *pos)
  82{
  83        return *pos < NR_CPUS ? cpu_data + *pos : NULL;
  84}
  85
  86static void *c_next(struct seq_file *m, void *v, loff_t *pos)
  87{
  88        ++*pos;
  89        return c_start(m, pos);
  90}
  91
  92static void c_stop(struct seq_file *m, void *v)
  93{
  94}
  95
  96const 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 */
 104unsigned long uml_physmem;
 105EXPORT_SYMBOL(uml_physmem);
 106
 107unsigned long uml_reserved; /* Also modified in mem_init */
 108unsigned long start_vm;
 109unsigned long end_vm;
 110
 111/* Set in uml_ncpus_setup */
 112int ncpus = 1;
 113
 114/* Set in early boot */
 115static int have_root __initdata = 0;
 116
 117/* Set in uml_mem_setup and modified in linux_main */
 118long long physmem_size = 32 * 1024 * 1024;
 119
 120static const char *usage_string =
 121"User Mode Linux v%s\n"
 122"       available at http://user-mode-linux.sourceforge.net/\n\n";
 123
 124static 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
 137static 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
 152static 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
 166static 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
 182static 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
 201static 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
 216static 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
 228static 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
 239static struct notifier_block panic_exit_notifier = {
 240        .notifier_call          = panic_exit,
 241        .next                   = NULL,
 242        .priority               = 0
 243};
 244
 245/* Set during early boot */
 246unsigned long task_size;
 247EXPORT_SYMBOL(task_size);
 248
 249unsigned long host_task_size;
 250
 251unsigned long brk_start;
 252unsigned long end_iomem;
 253EXPORT_SYMBOL(end_iomem);
 254
 255#define MIN_VMALLOC (32 * 1024 * 1024)
 256
 257extern char __binary_start;
 258
 259int __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
 376void __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
 384void __init check_bugs(void)
 385{
 386        arch_check_bugs();
 387        os_check_bugs();
 388}
 389
 390void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 391{
 392}
 393
 394#ifdef CONFIG_SMP
 395void alternatives_smp_module_add(struct module *mod, char *name,
 396                                 void *locks, void *locks_end,
 397                                 void *text,  void *text_end)
 398{
 399}
 400
 401void alternatives_smp_module_del(struct module *mod)
 402{
 403}
 404#endif
 405
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