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um_arch.c

/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include "linux/delay.h"
#include "linux/mm.h"
#include "linux/module.h"
#include "linux/seq_file.h"
#include "linux/string.h"
#include "linux/utsname.h"
#include "asm/pgtable.h"
#include "asm/processor.h"
#include "asm/setup.h"
#include "arch.h"
#include "as-layout.h"
#include "init.h"
#include "kern.h"
#include "mem_user.h"
#include "os.h"
#include "skas.h"

#define DEFAULT_COMMAND_LINE "root=98:0"

/* Changed in add_arg and setup_arch, which run before SMP is started */
static char __initdata command_line[COMMAND_LINE_SIZE] = { 0 };

static void __init add_arg(char *arg)
{
      if (strlen(command_line) + strlen(arg) + 1 > COMMAND_LINE_SIZE) {
            printf("add_arg: Too many command line arguments!\n");
            exit(1);
      }
      if (strlen(command_line) > 0)
            strcat(command_line, " ");
      strcat(command_line, arg);
}

/*
 * These fields are initialized at boot time and not changed.
 * XXX This structure is used only in the non-SMP case.  Maybe this
 * should be moved to smp.c.
 */
struct cpuinfo_um boot_cpu_data = {
      .loops_per_jiffy  = 0,
      .ipi_pipe         = { -1, -1 }
};

unsigned long thread_saved_pc(struct task_struct *task)
{
      /* FIXME: Need to look up userspace_pid by cpu */
      return os_process_pc(userspace_pid[0]);
}

/* Changed in setup_arch, which is called in early boot */
static char host_info[(__NEW_UTS_LEN + 1) * 5];

static int show_cpuinfo(struct seq_file *m, void *v)
{
      int index = 0;

#ifdef CONFIG_SMP
      index = (struct cpuinfo_um *) v - cpu_data;
      if (!cpu_online(index))
            return 0;
#endif

      seq_printf(m, "processor\t: %d\n", index);
      seq_printf(m, "vendor_id\t: User Mode Linux\n");
      seq_printf(m, "model name\t: UML\n");
      seq_printf(m, "mode\t\t: skas\n");
      seq_printf(m, "host\t\t: %s\n", host_info);
      seq_printf(m, "bogomips\t: %lu.%02lu\n\n",
               loops_per_jiffy/(500000/HZ),
               (loops_per_jiffy/(5000/HZ)) % 100);

      return 0;
}

static void *c_start(struct seq_file *m, loff_t *pos)
{
      return *pos < NR_CPUS ? cpu_data + *pos : NULL;
}

static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
      ++*pos;
      return c_start(m, pos);
}

static void c_stop(struct seq_file *m, void *v)
{
}

const struct seq_operations cpuinfo_op = {
      .start      = c_start,
      .next = c_next,
      .stop = c_stop,
      .show = show_cpuinfo,
};

/* Set in linux_main */
unsigned long host_task_size;
unsigned long task_size;
unsigned long uml_physmem;
unsigned long uml_reserved; /* Also modified in mem_init */
unsigned long start_vm;
unsigned long end_vm;

/* Set in uml_ncpus_setup */
int ncpus = 1;

/* Set in early boot */
static int have_root __initdata = 0;

/* Set in uml_mem_setup and modified in linux_main */
long long physmem_size = 32 * 1024 * 1024;

static char *usage_string =
"User Mode Linux v%s\n"
"     available at http://user-mode-linux.sourceforge.net/\n\n";

static int __init uml_version_setup(char *line, int *add)
{
      printf("%s\n", init_utsname()->release);
      exit(0);

      return 0;
}

__uml_setup("--version", uml_version_setup,
"--version\n"
"    Prints the version number of the kernel.\n\n"
);

static int __init uml_root_setup(char *line, int *add)
{
      have_root = 1;
      return 0;
}

__uml_setup("root=", uml_root_setup,
"root=<file containing the root fs>\n"
"    This is actually used by the generic kernel in exactly the same\n"
"    way as in any other kernel. If you configure a number of block\n"
"    devices and want to boot off something other than ubd0, you \n"
"    would use something like:\n"
"        root=/dev/ubd5\n\n"
);

static int __init no_skas_debug_setup(char *line, int *add)
{
      printf("'debug' is not necessary to gdb UML in skas mode - run \n");
      printf("'gdb linux'");

      return 0;
}

__uml_setup("debug", no_skas_debug_setup,
"debug\n"
"    this flag is not needed to run gdb on UML in skas mode\n\n"
);

#ifdef CONFIG_SMP
static int __init uml_ncpus_setup(char *line, int *add)
{
      if (!sscanf(line, "%d", &ncpus)) {
            printf("Couldn't parse [%s]\n", line);
            return -1;
      }

      return 0;
}

__uml_setup("ncpus=", uml_ncpus_setup,
"ncpus=<# of desired CPUs>\n"
"    This tells an SMP kernel how many virtual processors to start.\n\n"
);
#endif

static int __init Usage(char *line, int *add)
{
      const char **p;

      printf(usage_string, init_utsname()->release);
      p = &__uml_help_start;
      while (p < &__uml_help_end) {
            printf("%s", *p);
            p++;
      }
      exit(0);
      return 0;
}

__uml_setup("--help", Usage,
"--help\n"
"    Prints this message.\n\n"
);

static int __init uml_checksetup(char *line, int *add)
{
      struct uml_param *p;

      p = &__uml_setup_start;
      while(p < &__uml_setup_end) {
            int n;

            n = strlen(p->str);
            if (!strncmp(line, p->str, n) && p->setup_func(line + n, add))
                  return 1;
            p++;
      }
      return 0;
}

static void __init uml_postsetup(void)
{
      initcall_t *p;

      p = &__uml_postsetup_start;
      while(p < &__uml_postsetup_end) {
            (*p)();
            p++;
      }
      return;
}

/* Set during early boot */
unsigned long brk_start;
unsigned long end_iomem;
EXPORT_SYMBOL(end_iomem);

#define MIN_VMALLOC (32 * 1024 * 1024)

extern char __binary_start;

static unsigned long set_task_sizes_skas(unsigned long *task_size_out)
{
      /* Round up to the nearest 4M */
      unsigned long host_task_size = ROUND_4M((unsigned long)
                                    &host_task_size);

      if (!skas_needs_stub)
            *task_size_out = host_task_size;
      else
            *task_size_out = STUB_START & PGDIR_MASK;

      return host_task_size;
}

int __init linux_main(int argc, char **argv)
{
      unsigned long avail, diff;
      unsigned long virtmem_size, max_physmem;
      unsigned int i, add;
      char * mode;

      for (i = 1; i < argc; i++) {
            if ((i == 1) && (argv[i][0] == ' '))
                  continue;
            add = 1;
            uml_checksetup(argv[i], &add);
            if (add)
                  add_arg(argv[i]);
      }
      if (have_root == 0)
            add_arg(DEFAULT_COMMAND_LINE);

      /* OS sanity checks that need to happen before the kernel runs */
      os_early_checks();

      can_do_skas();

      if (proc_mm && ptrace_faultinfo)
            mode = "SKAS3";
      else
            mode = "SKAS0";

      printf("UML running in %s mode\n", mode);

      host_task_size = set_task_sizes_skas(&task_size);

      /*
       * Setting up handlers to 'sig_info' struct
       */
      os_fill_handlinfo(handlinfo_kern);

      brk_start = (unsigned long) sbrk(0);

      /*
       * Increase physical memory size for exec-shield users
       * so they actually get what they asked for. This should
       * add zero for non-exec shield users
       */

      diff = UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
      if (diff > 1024 * 1024) {
            printf("Adding %ld bytes to physical memory to account for "
                   "exec-shield gap\n", diff);
            physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
      }

      uml_physmem = (unsigned long) &__binary_start & PAGE_MASK;

      /* Reserve up to 4M after the current brk */
      uml_reserved = ROUND_4M(brk_start) + (1 << 22);

      setup_machinename(init_utsname()->machine);

      highmem = 0;
      iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
      max_physmem = get_kmem_end() - uml_physmem - iomem_size - MIN_VMALLOC;

      /*
       * Zones have to begin on a 1 << MAX_ORDER page boundary,
       * so this makes sure that's true for highmem
       */
      max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
      if (physmem_size + iomem_size > max_physmem) {
            highmem = physmem_size + iomem_size - max_physmem;
            physmem_size -= highmem;
#ifndef CONFIG_HIGHMEM
            highmem = 0;
            printf("CONFIG_HIGHMEM not enabled - physical memory shrunk "
                   "to %Lu bytes\n", physmem_size);
#endif
      }

      high_physmem = uml_physmem + physmem_size;
      end_iomem = high_physmem + iomem_size;
      high_memory = (void *) end_iomem;

      start_vm = VMALLOC_START;

      setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
      if (init_maps(physmem_size, iomem_size, highmem)) {
            printf("Failed to allocate mem_map for %Lu bytes of physical "
                   "memory and %Lu bytes of highmem\n", physmem_size,
                   highmem);
            exit(1);
      }

      virtmem_size = physmem_size;
      avail = get_kmem_end() - start_vm;
      if (physmem_size > avail)
            virtmem_size = avail;
      end_vm = start_vm + virtmem_size;

      if (virtmem_size < physmem_size)
            printf("Kernel virtual memory size shrunk to %lu bytes\n",
                   virtmem_size);

      uml_postsetup();

      stack_protections((unsigned long) &init_thread_info);
      os_flush_stdout();

      return start_uml();
}

extern int uml_exitcode;

static int panic_exit(struct notifier_block *self, unsigned long unused1,
                  void *unused2)
{
      bust_spinlocks(1);
      show_regs(&(current->thread.regs));
      bust_spinlocks(0);
      uml_exitcode = 1;
      os_dump_core();
      return 0;
}

static struct notifier_block panic_exit_notifier = {
      .notifier_call          = panic_exit,
      .next                   = NULL,
      .priority         = 0
};

void __init setup_arch(char **cmdline_p)
{
      atomic_notifier_chain_register(&panic_notifier_list,
                  &panic_exit_notifier);
      paging_init();
      strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
      *cmdline_p = command_line;
      setup_hostinfo(host_info, sizeof host_info);
}

void __init check_bugs(void)
{
      arch_check_bugs();
      os_check_bugs();
}

void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
{
}

#ifdef CONFIG_SMP
void alternatives_smp_module_add(struct module *mod, char *name,
                         void *locks, void *locks_end,
                         void *text,  void *text_end)
{
}

void alternatives_smp_module_del(struct module *mod)
{
}
#endif

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