[S390] take mmap_sem when walking guest page table

[deliverable/linux.git] / arch / s390 / kernel / setup.c

/*
 *  arch/s390/kernel/setup.c
 *
 *  S390 version
 *    Copyright (C) IBM Corp. 1999,2010
 *    Author(s): Hartmut Penner (hp@de.ibm.com),
 *               Martin Schwidefsky (schwidefsky@de.ibm.com)
 *
 *  Derived from "arch/i386/kernel/setup.c"
 *    Copyright (C) 1995, Linus Torvalds
 */

/*
 * This file handles the architecture-dependent parts of initialization
 */

#define KMSG_COMPONENT "setup"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/initrd.h>
#include <linux/bootmem.h>
#include <linux/root_dev.h>
#include <linux/console.h>
#include <linux/kernel_stat.h>
#include <linux/device.h>
#include <linux/notifier.h>
#include <linux/pfn.h>
#include <linux/ctype.h>
#include <linux/reboot.h>
#include <linux/topology.h>
#include <linux/ftrace.h>
#include <linux/kexec.h>
#include <linux/crash_dump.h>
#include <linux/memory.h>

#include <asm/ipl.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/smp.h>
#include <asm/mmu_context.h>
#include <asm/cpcmd.h>
#include <asm/lowcore.h>
#include <asm/irq.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/sections.h>
#include <asm/ebcdic.h>
#include <asm/compat.h>
#include <asm/kvm_virtio.h>
#include <asm/diag.h>

long psw_kernel_bits    = PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_ASC_PRIMARY |
                          PSW_MASK_EA | PSW_MASK_BA;
long psw_user_bits      = PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT |
                          PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_MASK_MCHECK |
                          PSW_MASK_PSTATE | PSW_ASC_HOME;

/*
 * User copy operations.
 */
struct uaccess_ops uaccess;
EXPORT_SYMBOL(uaccess);

/*
 * Machine setup..
 */
unsigned int console_mode = 0;
EXPORT_SYMBOL(console_mode);

unsigned int console_devno = -1;
EXPORT_SYMBOL(console_devno);

unsigned int console_irq = -1;
EXPORT_SYMBOL(console_irq);

unsigned long elf_hwcap = 0;
char elf_platform[ELF_PLATFORM_SIZE];

struct mem_chunk __initdata memory_chunk[MEMORY_CHUNKS];

int __initdata memory_end_set;
unsigned long __initdata memory_end;

/* An array with a pointer to the lowcore of every CPU. */
struct _lowcore *lowcore_ptr[NR_CPUS];
EXPORT_SYMBOL(lowcore_ptr);

/*
 * This is set up by the setup-routine at boot-time
 * for S390 need to find out, what we have to setup
 * using address 0x10400 ...
 */

#include <asm/setup.h>

/*
 * condev= and conmode= setup parameter.
 */

static int __init condev_setup(char *str)
{
        int vdev;

        vdev = simple_strtoul(str, &str, 0);
        if (vdev >= 0 && vdev < 65536) {
                console_devno = vdev;
                console_irq = -1;
        }
        return 1;
}

__setup("condev=", condev_setup);

static void __init set_preferred_console(void)
{
        if (MACHINE_IS_KVM)
                add_preferred_console("hvc", 0, NULL);
        else if (CONSOLE_IS_3215 || CONSOLE_IS_SCLP)
                add_preferred_console("ttyS", 0, NULL);
        else if (CONSOLE_IS_3270)
                add_preferred_console("tty3270", 0, NULL);
}

static int __init conmode_setup(char *str)
{
#if defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
        if (strncmp(str, "hwc", 4) == 0 || strncmp(str, "sclp", 5) == 0)
                SET_CONSOLE_SCLP;
#endif
#if defined(CONFIG_TN3215_CONSOLE)
        if (strncmp(str, "3215", 5) == 0)
                SET_CONSOLE_3215;
#endif
#if defined(CONFIG_TN3270_CONSOLE)
        if (strncmp(str, "3270", 5) == 0)
                SET_CONSOLE_3270;
#endif
        set_preferred_console();
        return 1;
}

__setup("conmode=", conmode_setup);

static void __init conmode_default(void)
{
        char query_buffer[1024];
        char *ptr;

        if (MACHINE_IS_VM) {
                cpcmd("QUERY CONSOLE", query_buffer, 1024, NULL);
                console_devno = simple_strtoul(query_buffer + 5, NULL, 16);
                ptr = strstr(query_buffer, "SUBCHANNEL =");
                console_irq = simple_strtoul(ptr + 13, NULL, 16);
                cpcmd("QUERY TERM", query_buffer, 1024, NULL);
                ptr = strstr(query_buffer, "CONMODE");
                /*
                 * Set the conmode to 3215 so that the device recognition 
                 * will set the cu_type of the console to 3215. If the
                 * conmode is 3270 and we don't set it back then both
                 * 3215 and the 3270 driver will try to access the console
                 * device (3215 as console and 3270 as normal tty).
                 */
                cpcmd("TERM CONMODE 3215", NULL, 0, NULL);
                if (ptr == NULL) {
#if defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
                        SET_CONSOLE_SCLP;
#endif
                        return;
                }
                if (strncmp(ptr + 8, "3270", 4) == 0) {
#if defined(CONFIG_TN3270_CONSOLE)
                        SET_CONSOLE_3270;
#elif defined(CONFIG_TN3215_CONSOLE)
                        SET_CONSOLE_3215;
#elif defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
                        SET_CONSOLE_SCLP;
#endif
                } else if (strncmp(ptr + 8, "3215", 4) == 0) {
#if defined(CONFIG_TN3215_CONSOLE)
                        SET_CONSOLE_3215;
#elif defined(CONFIG_TN3270_CONSOLE)
                        SET_CONSOLE_3270;
#elif defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
                        SET_CONSOLE_SCLP;
#endif
                }
        } else {
#if defined(CONFIG_SCLP_CONSOLE) || defined(CONFIG_SCLP_VT220_CONSOLE)
                SET_CONSOLE_SCLP;
#endif
        }
}

#ifdef CONFIG_ZFCPDUMP
static void __init setup_zfcpdump(unsigned int console_devno)
{
        static char str[41];

        if (ipl_info.type != IPL_TYPE_FCP_DUMP)
                return;
        if (console_devno != -1)
                sprintf(str, " cio_ignore=all,!0.0.%04x,!0.0.%04x",
                        ipl_info.data.fcp.dev_id.devno, console_devno);
        else
                sprintf(str, " cio_ignore=all,!0.0.%04x",
                        ipl_info.data.fcp.dev_id.devno);
        strcat(boot_command_line, str);
        console_loglevel = 2;
}
#else
static inline void setup_zfcpdump(unsigned int console_devno) {}
#endif /* CONFIG_ZFCPDUMP */

 /*
 * Reboot, halt and power_off stubs. They just call _machine_restart,
 * _machine_halt or _machine_power_off. 
 */

void machine_restart(char *command)
{
        if ((!in_interrupt() && !in_atomic()) || oops_in_progress)
                /*
                 * Only unblank the console if we are called in enabled
                 * context or a bust_spinlocks cleared the way for us.
                 */
                console_unblank();
        _machine_restart(command);
}

void machine_halt(void)
{
        if (!in_interrupt() || oops_in_progress)
                /*
                 * Only unblank the console if we are called in enabled
                 * context or a bust_spinlocks cleared the way for us.
                 */
                console_unblank();
        _machine_halt();
}

void machine_power_off(void)
{
        if (!in_interrupt() || oops_in_progress)
                /*
                 * Only unblank the console if we are called in enabled
                 * context or a bust_spinlocks cleared the way for us.
                 */
                console_unblank();
        _machine_power_off();
}

/*
 * Dummy power off function.
 */
void (*pm_power_off)(void) = machine_power_off;

static int __init early_parse_mem(char *p)
{
        memory_end = memparse(p, &p);
        memory_end_set = 1;
        return 0;
}
early_param("mem", early_parse_mem);

unsigned int user_mode = HOME_SPACE_MODE;
EXPORT_SYMBOL_GPL(user_mode);

static int set_amode_primary(void)
{
        psw_kernel_bits = (psw_kernel_bits & ~PSW_MASK_ASC) | PSW_ASC_HOME;
        psw_user_bits = (psw_user_bits & ~PSW_MASK_ASC) | PSW_ASC_PRIMARY;
#ifdef CONFIG_COMPAT
        psw32_user_bits =
                (psw32_user_bits & ~PSW32_MASK_ASC) | PSW32_ASC_PRIMARY;
#endif

        if (MACHINE_HAS_MVCOS) {
                memcpy(&uaccess, &uaccess_mvcos_switch, sizeof(uaccess));
                return 1;
        } else {
                memcpy(&uaccess, &uaccess_pt, sizeof(uaccess));
                return 0;
        }
}

/*
 * Switch kernel/user addressing modes?
 */
static int __init early_parse_switch_amode(char *p)
{
        user_mode = PRIMARY_SPACE_MODE;
        return 0;
}
early_param("switch_amode", early_parse_switch_amode);

static int __init early_parse_user_mode(char *p)
{
        if (p && strcmp(p, "primary") == 0)
                user_mode = PRIMARY_SPACE_MODE;
        else if (!p || strcmp(p, "home") == 0)
                user_mode = HOME_SPACE_MODE;
        else
                return 1;
        return 0;
}
early_param("user_mode", early_parse_user_mode);

static void setup_addressing_mode(void)
{
        if (user_mode == PRIMARY_SPACE_MODE) {
                if (set_amode_primary())
                        pr_info("Address spaces switched, "
                                "mvcos available\n");
                else
                        pr_info("Address spaces switched, "
                                "mvcos not available\n");
        }
}

static void __init
setup_lowcore(void)
{
        struct _lowcore *lc;

        /*
         * Setup lowcore for boot cpu
         */
        BUILD_BUG_ON(sizeof(struct _lowcore) != LC_PAGES * 4096);
        lc = __alloc_bootmem_low(LC_PAGES * PAGE_SIZE, LC_PAGES * PAGE_SIZE, 0);
        lc->restart_psw.mask = psw_kernel_bits;
        lc->restart_psw.addr =
                PSW_ADDR_AMODE | (unsigned long) psw_restart_int_handler;
        lc->external_new_psw.mask = psw_kernel_bits |
                PSW_MASK_DAT | PSW_MASK_MCHECK;
        lc->external_new_psw.addr =
                PSW_ADDR_AMODE | (unsigned long) ext_int_handler;
        lc->svc_new_psw.mask = psw_kernel_bits |
                PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
        lc->svc_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) system_call;
        lc->program_new_psw.mask = psw_kernel_bits |
                PSW_MASK_DAT | PSW_MASK_MCHECK;
        lc->program_new_psw.addr =
                PSW_ADDR_AMODE | (unsigned long) pgm_check_handler;
        lc->mcck_new_psw.mask = psw_kernel_bits;
        lc->mcck_new_psw.addr =
                PSW_ADDR_AMODE | (unsigned long) mcck_int_handler;
        lc->io_new_psw.mask = psw_kernel_bits |
                PSW_MASK_DAT | PSW_MASK_MCHECK;
        lc->io_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) io_int_handler;
        lc->clock_comparator = -1ULL;
        lc->kernel_stack = ((unsigned long) &init_thread_union) + THREAD_SIZE;
        lc->async_stack = (unsigned long)
                __alloc_bootmem(ASYNC_SIZE, ASYNC_SIZE, 0) + ASYNC_SIZE;
        lc->panic_stack = (unsigned long)
                __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0) + PAGE_SIZE;
        lc->current_task = (unsigned long) init_thread_union.thread_info.task;
        lc->thread_info = (unsigned long) &init_thread_union;
        lc->machine_flags = S390_lowcore.machine_flags;
        lc->stfl_fac_list = S390_lowcore.stfl_fac_list;
        memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
               MAX_FACILITY_BIT/8);
#ifndef CONFIG_64BIT
        if (MACHINE_HAS_IEEE) {
                lc->extended_save_area_addr = (__u32)
                        __alloc_bootmem_low(PAGE_SIZE, PAGE_SIZE, 0);
                /* enable extended save area */
                __ctl_set_bit(14, 29);
        }
#else
        lc->cmf_hpp = -1ULL;
        lc->vdso_per_cpu_data = (unsigned long) &lc->paste[0];
#endif
        lc->sync_enter_timer = S390_lowcore.sync_enter_timer;
        lc->async_enter_timer = S390_lowcore.async_enter_timer;
        lc->exit_timer = S390_lowcore.exit_timer;
        lc->user_timer = S390_lowcore.user_timer;
        lc->system_timer = S390_lowcore.system_timer;
        lc->steal_timer = S390_lowcore.steal_timer;
        lc->last_update_timer = S390_lowcore.last_update_timer;
        lc->last_update_clock = S390_lowcore.last_update_clock;
        lc->ftrace_func = S390_lowcore.ftrace_func;
        set_prefix((u32)(unsigned long) lc);
        lowcore_ptr[0] = lc;
}

static struct resource code_resource = {
        .name  = "Kernel code",
        .flags = IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource data_resource = {
        .name = "Kernel data",
        .flags = IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource bss_resource = {
        .name = "Kernel bss",
        .flags = IORESOURCE_BUSY | IORESOURCE_MEM,
};

static struct resource __initdata *standard_resources[] = {
        &code_resource,
        &data_resource,
        &bss_resource,
};

static void __init setup_resources(void)
{
        struct resource *res, *std_res, *sub_res;
        int i, j;

        code_resource.start = (unsigned long) &_text;
        code_resource.end = (unsigned long) &_etext - 1;
        data_resource.start = (unsigned long) &_etext;
        data_resource.end = (unsigned long) &_edata - 1;
        bss_resource.start = (unsigned long) &__bss_start;
        bss_resource.end = (unsigned long) &__bss_stop - 1;

        for (i = 0; i < MEMORY_CHUNKS; i++) {
                if (!memory_chunk[i].size)
                        continue;
                if (memory_chunk[i].type == CHUNK_OLDMEM ||
                    memory_chunk[i].type == CHUNK_CRASHK)
                        continue;
                res = alloc_bootmem_low(sizeof(*res));
                res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
                switch (memory_chunk[i].type) {
                case CHUNK_READ_WRITE:
                case CHUNK_CRASHK:
                        res->name = "System RAM";
                        break;
                case CHUNK_READ_ONLY:
                        res->name = "System ROM";
                        res->flags |= IORESOURCE_READONLY;
                        break;
                default:
                        res->name = "reserved";
                }
                res->start = memory_chunk[i].addr;
                res->end = res->start + memory_chunk[i].size - 1;
                request_resource(&iomem_resource, res);

                for (j = 0; j < ARRAY_SIZE(standard_resources); j++) {
                        std_res = standard_resources[j];
                        if (std_res->start < res->start ||
                            std_res->start > res->end)
                                continue;
                        if (std_res->end > res->end) {
                                sub_res = alloc_bootmem_low(sizeof(*sub_res));
                                *sub_res = *std_res;
                                sub_res->end = res->end;
                                std_res->start = res->end + 1;
                                request_resource(res, sub_res);
                        } else {
                                request_resource(res, std_res);
                        }
                }
        }
}

unsigned long real_memory_size;
EXPORT_SYMBOL_GPL(real_memory_size);

static void __init setup_memory_end(void)
{
        unsigned long memory_size;
        unsigned long max_mem;
        int i;


#ifdef CONFIG_ZFCPDUMP
        if (ipl_info.type == IPL_TYPE_FCP_DUMP) {
                memory_end = ZFCPDUMP_HSA_SIZE;
                memory_end_set = 1;
        }
#endif
        memory_size = 0;
        memory_end &= PAGE_MASK;

        max_mem = memory_end ? min(VMEM_MAX_PHYS, memory_end) : VMEM_MAX_PHYS;
        memory_end = min(max_mem, memory_end);

        /*
         * Make sure all chunks are MAX_ORDER aligned so we don't need the
         * extra checks that HOLES_IN_ZONE would require.
         */
        for (i = 0; i < MEMORY_CHUNKS; i++) {
                unsigned long start, end;
                struct mem_chunk *chunk;
                unsigned long align;

                chunk = &memory_chunk[i];
                align = 1UL << (MAX_ORDER + PAGE_SHIFT - 1);
                start = (chunk->addr + align - 1) & ~(align - 1);
                end = (chunk->addr + chunk->size) & ~(align - 1);
                if (start >= end)
                        memset(chunk, 0, sizeof(*chunk));
                else {
                        chunk->addr = start;
                        chunk->size = end - start;
                }
        }

        for (i = 0; i < MEMORY_CHUNKS; i++) {
                struct mem_chunk *chunk = &memory_chunk[i];

                real_memory_size = max(real_memory_size,
                                       chunk->addr + chunk->size);
                if (chunk->addr >= max_mem) {
                        memset(chunk, 0, sizeof(*chunk));
                        continue;
                }
                if (chunk->addr + chunk->size > max_mem)
                        chunk->size = max_mem - chunk->addr;
                memory_size = max(memory_size, chunk->addr + chunk->size);
        }
        if (!memory_end)
                memory_end = memory_size;
}

void *restart_stack __attribute__((__section__(".data")));

/*
 * Setup new PSW and allocate stack for PSW restart interrupt
 */
static void __init setup_restart_psw(void)
{
        psw_t psw;

        restart_stack = __alloc_bootmem(ASYNC_SIZE, ASYNC_SIZE, 0);
        restart_stack += ASYNC_SIZE;

        /*
         * Setup restart PSW for absolute zero lowcore. This is necesary
         * if PSW restart is done on an offline CPU that has lowcore zero
         */
        psw.mask = PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_MASK_EA | PSW_MASK_BA;
        psw.addr = PSW_ADDR_AMODE | (unsigned long) psw_restart_int_handler;
        copy_to_absolute_zero(&S390_lowcore.restart_psw, &psw, sizeof(psw));
}

static void __init setup_vmcoreinfo(void)
{
#ifdef CONFIG_KEXEC
        unsigned long ptr = paddr_vmcoreinfo_note();

        copy_to_absolute_zero(&S390_lowcore.vmcore_info, &ptr, sizeof(ptr));
#endif
}

#ifdef CONFIG_CRASH_DUMP

/*
 * Find suitable location for crashkernel memory
 */
static unsigned long __init find_crash_base(unsigned long crash_size,
                                            char **msg)
{
        unsigned long crash_base;
        struct mem_chunk *chunk;
        int i;

        if (memory_chunk[0].size < crash_size) {
                *msg = "first memory chunk must be at least crashkernel size";
                return 0;
        }
        if (is_kdump_kernel() && (crash_size == OLDMEM_SIZE))
                return OLDMEM_BASE;

        for (i = MEMORY_CHUNKS - 1; i >= 0; i--) {
                chunk = &memory_chunk[i];
                if (chunk->size == 0)
                        continue;
                if (chunk->type != CHUNK_READ_WRITE)
                        continue;
                if (chunk->size < crash_size)
                        continue;
                crash_base = (chunk->addr + chunk->size) - crash_size;
                if (crash_base < crash_size)
                        continue;
                if (crash_base < ZFCPDUMP_HSA_SIZE_MAX)
                        continue;
                if (crash_base < (unsigned long) INITRD_START + INITRD_SIZE)
                        continue;
                return crash_base;
        }
        *msg = "no suitable area found";
        return 0;
}

/*
 * Check if crash_base and crash_size is valid
 */
static int __init verify_crash_base(unsigned long crash_base,
                                    unsigned long crash_size,
                                    char **msg)
{
        struct mem_chunk *chunk;
        int i;

        /*
         * Because we do the swap to zero, we must have at least 'crash_size'
         * bytes free space before crash_base
         */
        if (crash_size > crash_base) {
                *msg = "crashkernel offset must be greater than size";
                return -EINVAL;
        }

        /* First memory chunk must be at least crash_size */
        if (memory_chunk[0].size < crash_size) {
                *msg = "first memory chunk must be at least crashkernel size";
                return -EINVAL;
        }
        /* Check if we fit into the respective memory chunk */
        for (i = 0; i < MEMORY_CHUNKS; i++) {
                chunk = &memory_chunk[i];
                if (chunk->size == 0)
                        continue;
                if (crash_base < chunk->addr)
                        continue;
                if (crash_base >= chunk->addr + chunk->size)
                        continue;
                /* we have found the memory chunk */
                if (crash_base + crash_size > chunk->addr + chunk->size) {
                        *msg = "selected memory chunk is too small for "
                                "crashkernel memory";
                        return -EINVAL;
                }
                return 0;
        }
        *msg = "invalid memory range specified";
        return -EINVAL;
}

/*
 * Reserve kdump memory by creating a memory hole in the mem_chunk array
 */
static void __init reserve_kdump_bootmem(unsigned long addr, unsigned long size,
                                         int type)
{

        create_mem_hole(memory_chunk, addr, size, type);
}

/*
 * When kdump is enabled, we have to ensure that no memory from
 * the area [0 - crashkernel memory size] and
 * [crashk_res.start - crashk_res.end] is set offline.
 */
static int kdump_mem_notifier(struct notifier_block *nb,
                              unsigned long action, void *data)
{
        struct memory_notify *arg = data;

        if (arg->start_pfn < PFN_DOWN(resource_size(&crashk_res)))
                return NOTIFY_BAD;
        if (arg->start_pfn > PFN_DOWN(crashk_res.end))
                return NOTIFY_OK;
        if (arg->start_pfn + arg->nr_pages - 1 < PFN_DOWN(crashk_res.start))
                return NOTIFY_OK;
        return NOTIFY_BAD;
}

static struct notifier_block kdump_mem_nb = {
        .notifier_call = kdump_mem_notifier,
};

#endif

/*
 * Make sure that oldmem, where the dump is stored, is protected
 */
static void reserve_oldmem(void)
{
#ifdef CONFIG_CRASH_DUMP
        if (!OLDMEM_BASE)
                return;

        reserve_kdump_bootmem(OLDMEM_BASE, OLDMEM_SIZE, CHUNK_OLDMEM);
        reserve_kdump_bootmem(OLDMEM_SIZE, memory_end - OLDMEM_SIZE,
                              CHUNK_OLDMEM);
        if (OLDMEM_BASE + OLDMEM_SIZE == real_memory_size)
                saved_max_pfn = PFN_DOWN(OLDMEM_BASE) - 1;
        else
                saved_max_pfn = PFN_DOWN(real_memory_size) - 1;
#endif
}

/*
 * Reserve memory for kdump kernel to be loaded with kexec
 */
static void __init reserve_crashkernel(void)
{
#ifdef CONFIG_CRASH_DUMP
        unsigned long long crash_base, crash_size;
        char *msg;
        int rc;

        rc = parse_crashkernel(boot_command_line, memory_end, &crash_size,
                               &crash_base);
        if (rc || crash_size == 0)
                return;
        crash_base = ALIGN(crash_base, KEXEC_CRASH_MEM_ALIGN);
        crash_size = ALIGN(crash_size, KEXEC_CRASH_MEM_ALIGN);
        if (register_memory_notifier(&kdump_mem_nb))
                return;
        if (!crash_base)
                crash_base = find_crash_base(crash_size, &msg);
        if (!crash_base) {
                pr_info("crashkernel reservation failed: %s\n", msg);
                unregister_memory_notifier(&kdump_mem_nb);
                return;
        }
        if (verify_crash_base(crash_base, crash_size, &msg)) {
                pr_info("crashkernel reservation failed: %s\n", msg);
                unregister_memory_notifier(&kdump_mem_nb);
                return;
        }
        if (!OLDMEM_BASE && MACHINE_IS_VM)
                diag10_range(PFN_DOWN(crash_base), PFN_DOWN(crash_size));
        crashk_res.start = crash_base;
        crashk_res.end = crash_base + crash_size - 1;
        insert_resource(&iomem_resource, &crashk_res);
        reserve_kdump_bootmem(crash_base, crash_size, CHUNK_CRASHK);
        pr_info("Reserving %lluMB of memory at %lluMB "
                "for crashkernel (System RAM: %luMB)\n",
                crash_size >> 20, crash_base >> 20, memory_end >> 20);
#endif
}

static void __init
setup_memory(void)
{
        unsigned long bootmap_size;
        unsigned long start_pfn, end_pfn;
        int i;

        /*
         * partially used pages are not usable - thus
         * we are rounding upwards:
         */
        start_pfn = PFN_UP(__pa(&_end));
        end_pfn = max_pfn = PFN_DOWN(memory_end);

#ifdef CONFIG_BLK_DEV_INITRD
        /*
         * Move the initrd in case the bitmap of the bootmem allocater
         * would overwrite it.
         */

        if (INITRD_START && INITRD_SIZE) {
                unsigned long bmap_size;
                unsigned long start;

                bmap_size = bootmem_bootmap_pages(end_pfn - start_pfn + 1);
                bmap_size = PFN_PHYS(bmap_size);

                if (PFN_PHYS(start_pfn) + bmap_size > INITRD_START) {
                        start = PFN_PHYS(start_pfn) + bmap_size + PAGE_SIZE;

#ifdef CONFIG_CRASH_DUMP
                        if (OLDMEM_BASE) {
                                /* Move initrd behind kdump oldmem */
                                if (start + INITRD_SIZE > OLDMEM_BASE &&
                                    start < OLDMEM_BASE + OLDMEM_SIZE)
                                        start = OLDMEM_BASE + OLDMEM_SIZE;
                        }
#endif
                        if (start + INITRD_SIZE > memory_end) {
                                pr_err("initrd extends beyond end of "
                                       "memory (0x%08lx > 0x%08lx) "
                                       "disabling initrd\n",
                                       start + INITRD_SIZE, memory_end);
                                INITRD_START = INITRD_SIZE = 0;
                        } else {
                                pr_info("Moving initrd (0x%08lx -> "
                                        "0x%08lx, size: %ld)\n",
                                        INITRD_START, start, INITRD_SIZE);
                                memmove((void *) start, (void *) INITRD_START,
                                        INITRD_SIZE);
                                INITRD_START = start;
                        }
                }
        }
#endif

        /*
         * Initialize the boot-time allocator
         */
        bootmap_size = init_bootmem(start_pfn, end_pfn);

        /*
         * Register RAM areas with the bootmem allocator.
         */

        for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
                unsigned long start_chunk, end_chunk, pfn;

                if (memory_chunk[i].type != CHUNK_READ_WRITE &&
                    memory_chunk[i].type != CHUNK_CRASHK)
                        continue;
                start_chunk = PFN_DOWN(memory_chunk[i].addr);
                end_chunk = start_chunk + PFN_DOWN(memory_chunk[i].size);
                end_chunk = min(end_chunk, end_pfn);
                if (start_chunk >= end_chunk)
                        continue;
                add_active_range(0, start_chunk, end_chunk);
                pfn = max(start_chunk, start_pfn);
                for (; pfn < end_chunk; pfn++)
                        page_set_storage_key(PFN_PHYS(pfn),
                                             PAGE_DEFAULT_KEY, 0);
        }

        psw_set_key(PAGE_DEFAULT_KEY);

        free_bootmem_with_active_regions(0, max_pfn);

        /*
         * Reserve memory used for lowcore/command line/kernel image.
         */
        reserve_bootmem(0, (unsigned long)_ehead, BOOTMEM_DEFAULT);
        reserve_bootmem((unsigned long)_stext,
                        PFN_PHYS(start_pfn) - (unsigned long)_stext,
                        BOOTMEM_DEFAULT);
        /*
         * Reserve the bootmem bitmap itself as well. We do this in two
         * steps (first step was init_bootmem()) because this catches
         * the (very unlikely) case of us accidentally initializing the
         * bootmem allocator with an invalid RAM area.
         */
        reserve_bootmem(start_pfn << PAGE_SHIFT, bootmap_size,
                        BOOTMEM_DEFAULT);

#ifdef CONFIG_CRASH_DUMP
        if (crashk_res.start)
                reserve_bootmem(crashk_res.start,
                                crashk_res.end - crashk_res.start + 1,
                                BOOTMEM_DEFAULT);
        if (is_kdump_kernel())
                reserve_bootmem(elfcorehdr_addr - OLDMEM_BASE,
                                PAGE_ALIGN(elfcorehdr_size), BOOTMEM_DEFAULT);
#endif
#ifdef CONFIG_BLK_DEV_INITRD
        if (INITRD_START && INITRD_SIZE) {
                if (INITRD_START + INITRD_SIZE <= memory_end) {
                        reserve_bootmem(INITRD_START, INITRD_SIZE,
                                        BOOTMEM_DEFAULT);
                        initrd_start = INITRD_START;
                        initrd_end = initrd_start + INITRD_SIZE;
                } else {
                        pr_err("initrd extends beyond end of "
                               "memory (0x%08lx > 0x%08lx) "
                               "disabling initrd\n",
                               initrd_start + INITRD_SIZE, memory_end);
                        initrd_start = initrd_end = 0;
                }
        }
#endif
}

/*
 * Setup hardware capabilities.
 */
static void __init setup_hwcaps(void)
{
        static const int stfl_bits[6] = { 0, 2, 7, 17, 19, 21 };
        struct cpuid cpu_id;
        int i;

        /*
         * The store facility list bits numbers as found in the principles
         * of operation are numbered with bit 1UL<<31 as number 0 to
         * bit 1UL<<0 as number 31.
         *   Bit 0: instructions named N3, "backported" to esa-mode
         *   Bit 2: z/Architecture mode is active
         *   Bit 7: the store-facility-list-extended facility is installed
         *   Bit 17: the message-security assist is installed
         *   Bit 19: the long-displacement facility is installed
         *   Bit 21: the extended-immediate facility is installed
         *   Bit 22: extended-translation facility 3 is installed
         *   Bit 30: extended-translation facility 3 enhancement facility
         * These get translated to:
         *   HWCAP_S390_ESAN3 bit 0, HWCAP_S390_ZARCH bit 1,
         *   HWCAP_S390_STFLE bit 2, HWCAP_S390_MSA bit 3,
         *   HWCAP_S390_LDISP bit 4, HWCAP_S390_EIMM bit 5 and
         *   HWCAP_S390_ETF3EH bit 8 (22 && 30).
         */
        for (i = 0; i < 6; i++)
                if (test_facility(stfl_bits[i]))
                        elf_hwcap |= 1UL << i;

        if (test_facility(22) && test_facility(30))
                elf_hwcap |= HWCAP_S390_ETF3EH;

        /*
         * Check for additional facilities with store-facility-list-extended.
         * stfle stores doublewords (8 byte) with bit 1ULL<<63 as bit 0
         * and 1ULL<<0 as bit 63. Bits 0-31 contain the same information
         * as stored by stfl, bits 32-xxx contain additional facilities.
         * How many facility words are stored depends on the number of
         * doublewords passed to the instruction. The additional facilities
         * are:
         *   Bit 42: decimal floating point facility is installed
         *   Bit 44: perform floating point operation facility is installed
         * translated to:
         *   HWCAP_S390_DFP bit 6 (42 && 44).
         */
        if ((elf_hwcap & (1UL << 2)) && test_facility(42) && test_facility(44))
                elf_hwcap |= HWCAP_S390_DFP;

        /*
         * Huge page support HWCAP_S390_HPAGE is bit 7.
         */
        if (MACHINE_HAS_HPAGE)
                elf_hwcap |= HWCAP_S390_HPAGE;

        /*
         * 64-bit register support for 31-bit processes
         * HWCAP_S390_HIGH_GPRS is bit 9.
         */
        elf_hwcap |= HWCAP_S390_HIGH_GPRS;

        get_cpu_id(&cpu_id);
        switch (cpu_id.machine) {
        case 0x9672:
#if !defined(CONFIG_64BIT)
        default:        /* Use "g5" as default for 31 bit kernels. */
#endif
                strcpy(elf_platform, "g5");
                break;
        case 0x2064:
        case 0x2066:
#if defined(CONFIG_64BIT)
        default:        /* Use "z900" as default for 64 bit kernels. */
#endif
                strcpy(elf_platform, "z900");
                break;
        case 0x2084:
        case 0x2086:
                strcpy(elf_platform, "z990");
                break;
        case 0x2094:
        case 0x2096:
                strcpy(elf_platform, "z9-109");
                break;
        case 0x2097:
        case 0x2098:
                strcpy(elf_platform, "z10");
                break;
        case 0x2817:
        case 0x2818:
                strcpy(elf_platform, "z196");
                break;
        }
}

/*
 * Setup function called from init/main.c just after the banner
 * was printed.
 */

void __init
setup_arch(char **cmdline_p)
{
        /*
         * print what head.S has found out about the machine
         */
#ifndef CONFIG_64BIT
        if (MACHINE_IS_VM)
                pr_info("Linux is running as a z/VM "
                        "guest operating system in 31-bit mode\n");
        else if (MACHINE_IS_LPAR)
                pr_info("Linux is running natively in 31-bit mode\n");
        if (MACHINE_HAS_IEEE)
                pr_info("The hardware system has IEEE compatible "
                        "floating point units\n");
        else
                pr_info("The hardware system has no IEEE compatible "
                        "floating point units\n");
#else /* CONFIG_64BIT */
        if (MACHINE_IS_VM)
                pr_info("Linux is running as a z/VM "
                        "guest operating system in 64-bit mode\n");
        else if (MACHINE_IS_KVM)
                pr_info("Linux is running under KVM in 64-bit mode\n");
        else if (MACHINE_IS_LPAR)
                pr_info("Linux is running natively in 64-bit mode\n");
#endif /* CONFIG_64BIT */

        /* Have one command line that is parsed and saved in /proc/cmdline */
        /* boot_command_line has been already set up in early.c */
        *cmdline_p = boot_command_line;

        ROOT_DEV = Root_RAM0;

        init_mm.start_code = PAGE_OFFSET;
        init_mm.end_code = (unsigned long) &_etext;
        init_mm.end_data = (unsigned long) &_edata;
        init_mm.brk = (unsigned long) &_end;

        if (MACHINE_HAS_MVCOS)
                memcpy(&uaccess, &uaccess_mvcos, sizeof(uaccess));
        else
                memcpy(&uaccess, &uaccess_std, sizeof(uaccess));

        parse_early_param();

        setup_ipl();
        setup_memory_end();
        setup_addressing_mode();
        reserve_oldmem();
        reserve_crashkernel();
        setup_memory();
        setup_resources();
        setup_vmcoreinfo();
        setup_restart_psw();
        setup_lowcore();

        cpu_init();
        s390_init_cpu_topology();

        /*
         * Setup capabilities (ELF_HWCAP & ELF_PLATFORM).
         */
        setup_hwcaps();

        /*
         * Create kernel page tables and switch to virtual addressing.
         */
        paging_init();

        /* Setup default console */
        conmode_default();
        set_preferred_console();

        /* Setup zfcpdump support */
        setup_zfcpdump(console_devno);
}