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 <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 */
  32static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };
  33
  34static 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 */
  50struct cpuinfo_um boot_cpu_data = {
  51        .loops_per_jiffy        = 0,
  52        .ipi_pipe               = { -1, -1 }
  53};
  54
  55union 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 */
  60static char host_info[(__NEW_UTS_LEN + 1) * 5];
  61
  62static 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
  78static void *c_start(struct seq_file *m, loff_t *pos)
  79{
  80        return *pos < NR_CPUS ? cpu_data + *pos : NULL;
  81}
  82
  83static void *c_next(struct seq_file *m, void *v, loff_t *pos)
  84{
  85        ++*pos;
  86        return c_start(m, pos);
  87}
  88
  89static void c_stop(struct seq_file *m, void *v)
  90{
  91}
  92
  93const 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 */
 101unsigned long uml_physmem;
 102EXPORT_SYMBOL(uml_physmem);
 103
 104unsigned long uml_reserved; /* Also modified in mem_init */
 105unsigned long start_vm;
 106unsigned long end_vm;
 107
 108/* Set in uml_ncpus_setup */
 109int ncpus = 1;
 110
 111/* Set in early boot */
 112static int have_root __initdata = 0;
 113
 114/* Set in uml_mem_setup and modified in linux_main */
 115long long physmem_size = 32 * 1024 * 1024;
 116
 117static const char *usage_string =
 118"User Mode Linux v%s\n"
 119"       available at http://user-mode-linux.sourceforge.net/\n\n";
 120
 121static 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
 135static 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
 150static 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
 163static 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
 183static 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
 198static 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
 210static 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
 221static struct notifier_block panic_exit_notifier = {
 222        .notifier_call          = panic_exit,
 223        .next                   = NULL,
 224        .priority               = 0
 225};
 226
 227void 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 */
 238unsigned long task_size;
 239EXPORT_SYMBOL(task_size);
 240
 241unsigned long host_task_size;
 242
 243unsigned long brk_start;
 244unsigned long end_iomem;
 245EXPORT_SYMBOL(end_iomem);
 246
 247#define MIN_VMALLOC (32 * 1024 * 1024)
 248
 249int __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
 337int __init __weak read_initrd(void)
 338{
 339        return 0;
 340}
 341
 342void __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
 355void __init check_bugs(void)
 356{
 357        arch_check_bugs();
 358        os_check_bugs();
 359}
 360
 361void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 362{
 363}
 364