um_arch.c

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

#include <linux/delay.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/utsname.h>
#include <linux/sched.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/setup.h>
#include <as-layout.h>
#include <arch.h>
#include <init.h>
#include <kern.h>
#include <kern_util.h>
#include <mem_user.h>
#include <os.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 }
};

union thread_union cpu0_irqstack
    __attribute__((__section__(".data..init_irqstack"))) =
        { INIT_THREAD_INFO(init_task) };

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 uml_physmem;
EXPORT_SYMBOL(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 const 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'\n");

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

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

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

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

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

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
};

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

unsigned long host_task_size;

unsigned long brk_start;
unsigned long end_iomem;
EXPORT_SYMBOL(end_iomem);

#define MIN_VMALLOC (32 * 1024 * 1024)

extern char __binary_start;

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

    host_task_size = os_get_top_address();
    /*
     * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps
     * out
     */
    task_size = host_task_size & PGDIR_MASK;

    /* 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);

    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 = TASK_SIZE - 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;
    stack = (unsigned long) argv;
    stack &= ~(1024 * 1024 - 1);
    avail = stack - 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);

    atomic_notifier_chain_register(&panic_notifier_list,
                       &panic_exit_notifier);

    uml_postsetup();

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

    return start_uml();
}

void __init setup_arch(char **cmdline_p)
{
    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