/*
 * Common EFI (Extensible Firmware Interface) support functions
 * Based on Extensible Firmware Interface Specification version 1.0
 *
 * Copyright (C) 1999 VA Linux Systems
 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
 * Copyright (C) 1999-2002 Hewlett-Packard Co.
 *      David Mosberger-Tang <davidm@hpl.hp.com>
 *      Stephane Eranian <eranian@hpl.hp.com>
 * Copyright (C) 2005-2008 Intel Co.
 *      Fenghua Yu <fenghua.yu@intel.com>
 *      Bibo Mao <bibo.mao@intel.com>
 *      Chandramouli Narayanan <mouli@linux.intel.com>
 *      Huang Ying <ying.huang@intel.com>
 *
 * Copied from efi_32.c to eliminate the duplicated code between EFI
 * 32/64 support code. --ying 2007-10-26
 *
 * All EFI Runtime Services are not implemented yet as EFI only
 * supports physical mode addressing on SoftSDV. This is to be fixed
 * in a future version.  --drummond 1999-07-20
 *
 * Implemented EFI runtime services and virtual mode calls.  --davidm
 *
 * Goutham Rao: <goutham.rao@intel.com>
 *      Skip non-WB memory and ignore empty memory ranges.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/efi.h>
#include <linux/efi-bgrt.h>
#include <linux/export.h>
#include <linux/bootmem.h>
#include <linux/slab.h>
#include <linux/memblock.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/time.h>
#include <linux/io.h>
#include <linux/reboot.h>
#include <linux/bcd.h>

#include <asm/setup.h>
#include <asm/efi.h>
#include <asm/time.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/x86_init.h>
#include <asm/rtc.h>

#define EFI_DEBUG       1

#define EFI_MIN_RESERVE 5120

#define EFI_DUMMY_GUID \
        EFI_GUID(0x4424ac57, 0xbe4b, 0x47dd, 0x9e, 0x97, 0xed, 0x50, 0xf0, 0x9f, 0x92, 0xa9)

static efi_char16_t efi_dummy_name[6] = { 'D', 'U', 'M', 'M', 'Y', 0 };

struct efi_memory_map memmap;

static struct efi efi_phys __initdata;
static efi_system_table_t efi_systab __initdata;

unsigned long x86_efi_facility;

static __initdata efi_config_table_type_t arch_tables[] = {
#ifdef CONFIG_X86_UV
        {UV_SYSTEM_TABLE_GUID, "UVsystab", &efi.uv_systab},
#endif
        {NULL_GUID, NULL, NULL},
};

/*
 * Returns 1 if 'facility' is enabled, 0 otherwise.
 */
int efi_enabled(int facility)
{
        return test_bit(facility, &x86_efi_facility) != 0;
}
EXPORT_SYMBOL(efi_enabled);

static bool __initdata disable_runtime = false;
static int __init setup_noefi(char *arg)
{
        disable_runtime = true;
        return 0;
}
early_param("noefi", setup_noefi);

int add_efi_memmap;
EXPORT_SYMBOL(add_efi_memmap);

static int __init setup_add_efi_memmap(char *arg)
{
        add_efi_memmap = 1;
        return 0;
}
early_param("add_efi_memmap", setup_add_efi_memmap);

static bool efi_no_storage_paranoia;

static int __init setup_storage_paranoia(char *arg)
{
        efi_no_storage_paranoia = true;
        return 0;
}
early_param("efi_no_storage_paranoia", setup_storage_paranoia);


static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
{
        unsigned long flags;
        efi_status_t status;

        spin_lock_irqsave(&rtc_lock, flags);
        status = efi_call_virt2(get_time, tm, tc);
        spin_unlock_irqrestore(&rtc_lock, flags);
        return status;
}

static efi_status_t virt_efi_set_time(efi_time_t *tm)
{
        unsigned long flags;
        efi_status_t status;

        spin_lock_irqsave(&rtc_lock, flags);
        status = efi_call_virt1(set_time, tm);
        spin_unlock_irqrestore(&rtc_lock, flags);
        return status;
}

static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled,
                                             efi_bool_t *pending,
                                             efi_time_t *tm)
{
        unsigned long flags;
        efi_status_t status;

        spin_lock_irqsave(&rtc_lock, flags);
        status = efi_call_virt3(get_wakeup_time,
                                enabled, pending, tm);
        spin_unlock_irqrestore(&rtc_lock, flags);
        return status;
}

static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
{
        unsigned long flags;
        efi_status_t status;

        spin_lock_irqsave(&rtc_lock, flags);
        status = efi_call_virt2(set_wakeup_time,
                                enabled, tm);
        spin_unlock_irqrestore(&rtc_lock, flags);
        return status;
}

static efi_status_t virt_efi_get_variable(efi_char16_t *name,
                                          efi_guid_t *vendor,
                                          u32 *attr,
                                          unsigned long *data_size,
                                          void *data)
{
        return efi_call_virt5(get_variable,
                              name, vendor, attr,
                              data_size, data);
}

static efi_status_t virt_efi_get_next_variable(unsigned long *name_size,
                                               efi_char16_t *name,
                                               efi_guid_t *vendor)
{
        return efi_call_virt3(get_next_variable,
                              name_size, name, vendor);
}

static efi_status_t virt_efi_set_variable(efi_char16_t *name,
                                          efi_guid_t *vendor,
                                          u32 attr,
                                          unsigned long data_size,
                                          void *data)
{
        return efi_call_virt5(set_variable,
                              name, vendor, attr,
                              data_size, data);
}

static efi_status_t virt_efi_query_variable_info(u32 attr,
                                                 u64 *storage_space,
                                                 u64 *remaining_space,
                                                 u64 *max_variable_size)
{
        if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
                return EFI_UNSUPPORTED;

        return efi_call_virt4(query_variable_info, attr, storage_space,
                              remaining_space, max_variable_size);
}

static efi_status_t virt_efi_get_next_high_mono_count(u32 *count)
{
        return efi_call_virt1(get_next_high_mono_count, count);
}

static void virt_efi_reset_system(int reset_type,
                                  efi_status_t status,
                                  unsigned long data_size,
                                  efi_char16_t *data)
{
        efi_call_virt4(reset_system, reset_type, status,
                       data_size, data);
}

static efi_status_t virt_efi_update_capsule(efi_capsule_header_t **capsules,
                                            unsigned long count,
                                            unsigned long sg_list)
{
        if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
                return EFI_UNSUPPORTED;

        return efi_call_virt3(update_capsule, capsules, count, sg_list);
}

static efi_status_t virt_efi_query_capsule_caps(efi_capsule_header_t **capsules,
                                                unsigned long count,
                                                u64 *max_size,
                                                int *reset_type)
{
        if (efi.runtime_version < EFI_2_00_SYSTEM_TABLE_REVISION)
                return EFI_UNSUPPORTED;

        return efi_call_virt4(query_capsule_caps, capsules, count, max_size,
                              reset_type);
}

static efi_status_t __init phys_efi_set_virtual_address_map(
        unsigned long memory_map_size,
        unsigned long descriptor_size,
        u32 descriptor_version,
        efi_memory_desc_t *virtual_map)
{
        efi_status_t status;

        efi_call_phys_prelog();
        status = efi_call_phys4(efi_phys.set_virtual_address_map,
                                memory_map_size, descriptor_size,
                                descriptor_version, virtual_map);
        efi_call_phys_epilog();
        return status;
}

static efi_status_t __init phys_efi_get_time(efi_time_t *tm,
                                             efi_time_cap_t *tc)
{
        unsigned long flags;
        efi_status_t status;

        spin_lock_irqsave(&rtc_lock, flags);
        efi_call_phys_prelog();
        status = efi_call_phys2(efi_phys.get_time, virt_to_phys(tm),
                                virt_to_phys(tc));
        efi_call_phys_epilog();
        spin_unlock_irqrestore(&rtc_lock, flags);
        return status;
}

int efi_set_rtc_mmss(const struct timespec *now)
{
        unsigned long nowtime = now->tv_sec;
        efi_status_t    status;
        efi_time_t      eft;
        efi_time_cap_t  cap;
        struct rtc_time tm;

        status = efi.get_time(&eft, &cap);
        if (status != EFI_SUCCESS) {
                pr_err("Oops: efitime: can't read time!\n");
                return -1;
        }

        rtc_time_to_tm(nowtime, &tm);
        if (!rtc_valid_tm(&tm)) {
                eft.year = tm.tm_year + 1900;
                eft.month = tm.tm_mon + 1;
                eft.day = tm.tm_mday;
                eft.minute = tm.tm_min;
                eft.second = tm.tm_sec;
                eft.nanosecond = 0;
        } else {
                printk(KERN_ERR
                       "%s: Invalid EFI RTC value: write of %lx to EFI RTC failed\n",
                       __FUNCTION__, nowtime);
                return -1;
        }

        status = efi.set_time(&eft);
        if (status != EFI_SUCCESS) {
                pr_err("Oops: efitime: can't write time!\n");
                return -1;
        }
        return 0;
}

void efi_get_time(struct timespec *now)
{
        efi_status_t status;
        efi_time_t eft;
        efi_time_cap_t cap;

        status = efi.get_time(&eft, &cap);
        if (status != EFI_SUCCESS)
                pr_err("Oops: efitime: can't read time!\n");

        now->tv_sec = mktime(eft.year, eft.month, eft.day, eft.hour,
                             eft.minute, eft.second);
        now->tv_nsec = 0;
}

/*
 * Tell the kernel about the EFI memory map.  This might include
 * more than the max 128 entries that can fit in the e820 legacy
 * (zeropage) memory map.
 */

static void __init do_add_efi_memmap(void)
{
        void *p;

        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
                efi_memory_desc_t *md = p;
                unsigned long long start = md->phys_addr;
                unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
                int e820_type;

                switch (md->type) {
                case EFI_LOADER_CODE:
                case EFI_LOADER_DATA:
                case EFI_BOOT_SERVICES_CODE:
                case EFI_BOOT_SERVICES_DATA:
                case EFI_CONVENTIONAL_MEMORY:
                        if (md->attribute & EFI_MEMORY_WB)
                                e820_type = E820_RAM;
                        else
                                e820_type = E820_RESERVED;
                        break;
                case EFI_ACPI_RECLAIM_MEMORY:
                        e820_type = E820_ACPI;
                        break;
                case EFI_ACPI_MEMORY_NVS:
                        e820_type = E820_NVS;
                        break;
                case EFI_UNUSABLE_MEMORY:
                        e820_type = E820_UNUSABLE;
                        break;
                default:
                        /*
                         * EFI_RESERVED_TYPE EFI_RUNTIME_SERVICES_CODE
                         * EFI_RUNTIME_SERVICES_DATA EFI_MEMORY_MAPPED_IO
                         * EFI_MEMORY_MAPPED_IO_PORT_SPACE EFI_PAL_CODE
                         */
                        e820_type = E820_RESERVED;
                        break;
                }
                e820_add_region(start, size, e820_type);
        }
        sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
}

int __init efi_memblock_x86_reserve_range(void)
{
        struct efi_info *e = &boot_params.efi_info;
        unsigned long pmap;

#ifdef CONFIG_X86_32
        /* Can't handle data above 4GB at this time */
        if (e->efi_memmap_hi) {
                pr_err("Memory map is above 4GB, disabling EFI.\n");
                return -EINVAL;
        }
        pmap =  e->efi_memmap;
#else
        pmap = (e->efi_memmap | ((__u64)e->efi_memmap_hi << 32));
#endif
        memmap.phys_map         = (void *)pmap;
        memmap.nr_map           = e->efi_memmap_size /
                                  e->efi_memdesc_size;
        memmap.desc_size        = e->efi_memdesc_size;
        memmap.desc_version     = e->efi_memdesc_version;

        memblock_reserve(pmap, memmap.nr_map * memmap.desc_size);

        efi.memmap = &memmap;

        return 0;
}

#if EFI_DEBUG
static void __init print_efi_memmap(void)
{
        efi_memory_desc_t *md;
        void *p;
        int i;

        for (p = memmap.map, i = 0;
             p < memmap.map_end;
             p += memmap.desc_size, i++) {
                md = p;
                pr_info("mem%02u: type=%u, attr=0x%llx, "
                        "range=[0x%016llx-0x%016llx) (%lluMB)\n",
                        i, md->type, md->attribute, md->phys_addr,
                        md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT),
                        (md->num_pages >> (20 - EFI_PAGE_SHIFT)));
        }
}
#endif  /*  EFI_DEBUG  */

void __init efi_reserve_boot_services(void)
{
        void *p;

        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
                efi_memory_desc_t *md = p;
                u64 start = md->phys_addr;
                u64 size = md->num_pages << EFI_PAGE_SHIFT;

                if (md->type != EFI_BOOT_SERVICES_CODE &&
                    md->type != EFI_BOOT_SERVICES_DATA)
                        continue;
                /* Only reserve where possible:
                 * - Not within any already allocated areas
                 * - Not over any memory area (really needed, if above?)
                 * - Not within any part of the kernel
                 * - Not the bios reserved area
                */
                if ((start+size >= __pa_symbol(_text)
                                && start <= __pa_symbol(_end)) ||
                        !e820_all_mapped(start, start+size, E820_RAM) ||
                        memblock_is_region_reserved(start, size)) {
                        /* Could not reserve, skip it */
                        md->num_pages = 0;
                        memblock_dbg("Could not reserve boot range "
                                        "[0x%010llx-0x%010llx]\n",
                                                start, start+size-1);
                } else
                        memblock_reserve(start, size);
        }
}

void __init efi_unmap_memmap(void)
{
        clear_bit(EFI_MEMMAP, &x86_efi_facility);
        if (memmap.map) {
                early_iounmap(memmap.map, memmap.nr_map * memmap.desc_size);
                memmap.map = NULL;
        }
}

void __init efi_free_boot_services(void)
{
        void *p;

        if (!efi_is_native())
                return;

        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
                efi_memory_desc_t *md = p;
                unsigned long long start = md->phys_addr;
                unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;

                if (md->type != EFI_BOOT_SERVICES_CODE &&
                    md->type != EFI_BOOT_SERVICES_DATA)
                        continue;

                /* Could not reserve boot area */
                if (!size)
                        continue;

                free_bootmem_late(start, size);
        }

        efi_unmap_memmap();
}

static int __init efi_systab_init(void *phys)
{
        if (efi_enabled(EFI_64BIT)) {
                efi_system_table_64_t *systab64;
                u64 tmp = 0;

                systab64 = early_ioremap((unsigned long)phys,
                                         sizeof(*systab64));
                if (systab64 == NULL) {
                        pr_err("Couldn't map the system table!\n");
                        return -ENOMEM;
                }

                efi_systab.hdr = systab64->hdr;
                efi_systab.fw_vendor = systab64->fw_vendor;
                tmp |= systab64->fw_vendor;
                efi_systab.fw_revision = systab64->fw_revision;
                efi_systab.con_in_handle = systab64->con_in_handle;
                tmp |= systab64->con_in_handle;
                efi_systab.con_in = systab64->con_in;
                tmp |= systab64->con_in;
                efi_systab.con_out_handle = systab64->con_out_handle;
                tmp |= systab64->con_out_handle;
                efi_systab.con_out = systab64->con_out;
                tmp |= systab64->con_out;
                efi_systab.stderr_handle = systab64->stderr_handle;
                tmp |= systab64->stderr_handle;
                efi_systab.stderr = systab64->stderr;
                tmp |= systab64->stderr;
                efi_systab.runtime = (void *)(unsigned long)systab64->runtime;
                tmp |= systab64->runtime;
                efi_systab.boottime = (void *)(unsigned long)systab64->boottime;
                tmp |= systab64->boottime;
                efi_systab.nr_tables = systab64->nr_tables;
                efi_systab.tables = systab64->tables;
                tmp |= systab64->tables;

                early_iounmap(systab64, sizeof(*systab64));
#ifdef CONFIG_X86_32
                if (tmp >> 32) {
                        pr_err("EFI data located above 4GB, disabling EFI.\n");
                        return -EINVAL;
                }
#endif
        } else {
                efi_system_table_32_t *systab32;

                systab32 = early_ioremap((unsigned long)phys,
                                         sizeof(*systab32));
                if (systab32 == NULL) {
                        pr_err("Couldn't map the system table!\n");
                        return -ENOMEM;
                }

                efi_systab.hdr = systab32->hdr;
                efi_systab.fw_vendor = systab32->fw_vendor;
                efi_systab.fw_revision = systab32->fw_revision;
                efi_systab.con_in_handle = systab32->con_in_handle;
                efi_systab.con_in = systab32->con_in;
                efi_systab.con_out_handle = systab32->con_out_handle;
                efi_systab.con_out = systab32->con_out;
                efi_systab.stderr_handle = systab32->stderr_handle;
                efi_systab.stderr = systab32->stderr;
                efi_systab.runtime = (void *)(unsigned long)systab32->runtime;
                efi_systab.boottime = (void *)(unsigned long)systab32->boottime;
                efi_systab.nr_tables = systab32->nr_tables;
                efi_systab.tables = systab32->tables;

                early_iounmap(systab32, sizeof(*systab32));
        }

        efi.systab = &efi_systab;

        /*
         * Verify the EFI Table
         */
        if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
                pr_err("System table signature incorrect!\n");
                return -EINVAL;
        }
        if ((efi.systab->hdr.revision >> 16) == 0)
                pr_err("Warning: System table version "
                       "%d.%02d, expected 1.00 or greater!\n",
                       efi.systab->hdr.revision >> 16,
                       efi.systab->hdr.revision & 0xffff);

        return 0;
}

static int __init efi_runtime_init(void)
{
        efi_runtime_services_t *runtime;

        /*
         * Check out the runtime services table. We need to map
         * the runtime services table so that we can grab the physical
         * address of several of the EFI runtime functions, needed to
         * set the firmware into virtual mode.
         */
        runtime = early_ioremap((unsigned long)efi.systab->runtime,
                                sizeof(efi_runtime_services_t));
        if (!runtime) {
                pr_err("Could not map the runtime service table!\n");
                return -ENOMEM;
        }
        /*
         * We will only need *early* access to the following
         * two EFI runtime services before set_virtual_address_map
         * is invoked.
         */
        efi_phys.get_time = (efi_get_time_t *)runtime->get_time;
        efi_phys.set_virtual_address_map =
                (efi_set_virtual_address_map_t *)
                runtime->set_virtual_address_map;
        /*
         * Make efi_get_time can be called before entering
         * virtual mode.
         */
        efi.get_time = phys_efi_get_time;
        early_iounmap(runtime, sizeof(efi_runtime_services_t));

        return 0;
}

static int __init efi_memmap_init(void)
{
        /* Map the EFI memory map */
        memmap.map = early_ioremap((unsigned long)memmap.phys_map,
                                   memmap.nr_map * memmap.desc_size);
        if (memmap.map == NULL) {
                pr_err("Could not map the memory map!\n");
                return -ENOMEM;
        }
        memmap.map_end = memmap.map + (memmap.nr_map * memmap.desc_size);

        if (add_efi_memmap)
                do_add_efi_memmap();

        return 0;
}

void __init efi_init(void)
{
        efi_char16_t *c16;
        char vendor[100] = "unknown";
        int i = 0;
        void *tmp;

#ifdef CONFIG_X86_32
        if (boot_params.efi_info.efi_systab_hi ||
            boot_params.efi_info.efi_memmap_hi) {
                pr_info("Table located above 4GB, disabling EFI.\n");
                return;
        }
        efi_phys.systab = (efi_system_table_t *)boot_params.efi_info.efi_systab;
#else
        efi_phys.systab = (efi_system_table_t *)
                          (boot_params.efi_info.efi_systab |
                          ((__u64)boot_params.efi_info.efi_systab_hi<<32));
#endif

        if (efi_systab_init(efi_phys.systab))
                return;

        set_bit(EFI_SYSTEM_TABLES, &x86_efi_facility);

        /*
         * Show what we know for posterity
         */
        c16 = tmp = early_ioremap(efi.systab->fw_vendor, 2);
        if (c16) {
                for (i = 0; i < sizeof(vendor) - 1 && *c16; ++i)
                        vendor[i] = *c16++;
                vendor[i] = '\0';
        } else
                pr_err("Could not map the firmware vendor!\n");
        early_iounmap(tmp, 2);

        pr_info("EFI v%u.%.02u by %s\n",
                efi.systab->hdr.revision >> 16,
                efi.systab->hdr.revision & 0xffff, vendor);

        if (efi_config_init(arch_tables))
                return;

        set_bit(EFI_CONFIG_TABLES, &x86_efi_facility);

        /*
         * Note: We currently don't support runtime services on an EFI
         * that doesn't match the kernel 32/64-bit mode.
         */

        if (!efi_is_native())
                pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n");
        else {
                if (disable_runtime || efi_runtime_init())
                        return;
                set_bit(EFI_RUNTIME_SERVICES, &x86_efi_facility);
        }

        if (efi_memmap_init())
                return;

        set_bit(EFI_MEMMAP, &x86_efi_facility);

#if EFI_DEBUG
        print_efi_memmap();
#endif
}

void __init efi_late_init(void)
{
        efi_bgrt_init();
}

void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
{
        u64 addr, npages;

        addr = md->virt_addr;
        npages = md->num_pages;

        memrange_efi_to_native(&addr, &npages);

        if (executable)
                set_memory_x(addr, npages);
        else
                set_memory_nx(addr, npages);
}

static void __init runtime_code_page_mkexec(void)
{
        efi_memory_desc_t *md;
        void *p;

        /* Make EFI runtime service code area executable */
        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
                md = p;

                if (md->type != EFI_RUNTIME_SERVICES_CODE)
                        continue;

                efi_set_executable(md, true);
        }
}

void efi_memory_uc(u64 addr, unsigned long size)
{
        unsigned long page_shift = 1UL << EFI_PAGE_SHIFT;
        u64 npages;

        npages = round_up(size, page_shift) / page_shift;
        memrange_efi_to_native(&addr, &npages);
        set_memory_uc(addr, npages);
}

/*
 * This function will switch the EFI runtime services to virtual mode.
 * Essentially, look through the EFI memmap and map every region that
 * has the runtime attribute bit set in its memory descriptor and update
 * that memory descriptor with the virtual address obtained from ioremap().
 * This enables the runtime services to be called without having to
 * thunk back into physical mode for every invocation.
 */
void __init efi_enter_virtual_mode(void)
{
        efi_memory_desc_t *md, *prev_md = NULL;
        efi_status_t status;
        unsigned long size;
        u64 end, systab, start_pfn, end_pfn;
        void *p, *va, *new_memmap = NULL;
        int count = 0;

        efi.systab = NULL;

        /*
         * We don't do virtual mode, since we don't do runtime services, on
         * non-native EFI
         */

        if (!efi_is_native()) {
                efi_unmap_memmap();
                return;
        }

        /* Merge contiguous regions of the same type and attribute */
        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
                u64 prev_size;
                md = p;

                if (!prev_md) {
                        prev_md = md;
                        continue;
                }

                if (prev_md->type != md->type ||
                    prev_md->attribute != md->attribute) {
                        prev_md = md;
                        continue;
                }

                prev_size = prev_md->num_pages << EFI_PAGE_SHIFT;

                if (md->phys_addr == (prev_md->phys_addr + prev_size)) {
                        prev_md->num_pages += md->num_pages;
                        md->type = EFI_RESERVED_TYPE;
                        md->attribute = 0;
                        continue;
                }
                prev_md = md;
        }

        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
                md = p;
                if (!(md->attribute & EFI_MEMORY_RUNTIME)) {
#ifdef CONFIG_X86_64
                        if (md->type != EFI_BOOT_SERVICES_CODE &&
                            md->type != EFI_BOOT_SERVICES_DATA)
#endif
                                continue;
                }

                size = md->num_pages << EFI_PAGE_SHIFT;
                end = md->phys_addr + size;

                start_pfn = PFN_DOWN(md->phys_addr);
                end_pfn = PFN_UP(end);
                if (pfn_range_is_mapped(start_pfn, end_pfn)) {
                        va = __va(md->phys_addr);

                        if (!(md->attribute & EFI_MEMORY_WB))
                                efi_memory_uc((u64)(unsigned long)va, size);
                } else
                        va = efi_ioremap(md->phys_addr, size,
                                         md->type, md->attribute);

                md->virt_addr = (u64) (unsigned long) va;

                if (!va) {
                        pr_err("ioremap of 0x%llX failed!\n",
                               (unsigned long long)md->phys_addr);
                        continue;
                }

                systab = (u64) (unsigned long) efi_phys.systab;
                if (md->phys_addr <= systab && systab < end) {
                        systab += md->virt_addr - md->phys_addr;
                        efi.systab = (efi_system_table_t *) (unsigned long) systab;
                }
                new_memmap = krealloc(new_memmap,
                                      (count + 1) * memmap.desc_size,
                                      GFP_KERNEL);
                memcpy(new_memmap + (count * memmap.desc_size), md,
                       memmap.desc_size);
                count++;
        }

        BUG_ON(!efi.systab);

        status = phys_efi_set_virtual_address_map(
                memmap.desc_size * count,
                memmap.desc_size,
                memmap.desc_version,
                (efi_memory_desc_t *)__pa(new_memmap));

        if (status != EFI_SUCCESS) {
                pr_alert("Unable to switch EFI into virtual mode "
                         "(status=%lx)!\n", status);
                panic("EFI call to SetVirtualAddressMap() failed!");
        }

        /*
         * Now that EFI is in virtual mode, update the function
         * pointers in the runtime service table to the new virtual addresses.
         *
         * Call EFI services through wrapper functions.
         */
        efi.runtime_version = efi_systab.hdr.revision;
        efi.get_time = virt_efi_get_time;
        efi.set_time = virt_efi_set_time;
        efi.get_wakeup_time = virt_efi_get_wakeup_time;
        efi.set_wakeup_time = virt_efi_set_wakeup_time;
        efi.get_variable = virt_efi_get_variable;
        efi.get_next_variable = virt_efi_get_next_variable;
        efi.set_variable = virt_efi_set_variable;
        efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count;
        efi.reset_system = virt_efi_reset_system;
        efi.set_virtual_address_map = NULL;
        efi.query_variable_info = virt_efi_query_variable_info;
        efi.update_capsule = virt_efi_update_capsule;
        efi.query_capsule_caps = virt_efi_query_capsule_caps;
        if (__supported_pte_mask & _PAGE_NX)
                runtime_code_page_mkexec();

        kfree(new_memmap);

        /* clean DUMMY object */
        efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
                         EFI_VARIABLE_NON_VOLATILE |
                         EFI_VARIABLE_BOOTSERVICE_ACCESS |
                         EFI_VARIABLE_RUNTIME_ACCESS,
                         0, NULL);
}

/*
 * Convenience functions to obtain memory types and attributes
 */
u32 efi_mem_type(unsigned long phys_addr)
{
        efi_memory_desc_t *md;
        void *p;

        if (!efi_enabled(EFI_MEMMAP))
                return 0;

        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
                md = p;
                if ((md->phys_addr <= phys_addr) &&
                    (phys_addr < (md->phys_addr +
                                  (md->num_pages << EFI_PAGE_SHIFT))))
                        return md->type;
        }
        return 0;
}

u64 efi_mem_attributes(unsigned long phys_addr)
{
        efi_memory_desc_t *md;
        void *p;

        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
                md = p;
                if ((md->phys_addr <= phys_addr) &&
                    (phys_addr < (md->phys_addr +
                                  (md->num_pages << EFI_PAGE_SHIFT))))
                        return md->attribute;
        }
        return 0;
}

/*
 * Some firmware has serious problems when using more than 50% of the EFI
 * variable store, i.e. it triggers bugs that can brick machines. Ensure that
 * we never use more than this safe limit.
 *
 * Return EFI_SUCCESS if it is safe to write 'size' bytes to the variable
 * store.
 */
efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
{
        efi_status_t status;
        u64 storage_size, remaining_size, max_size;

        if (!(attributes & EFI_VARIABLE_NON_VOLATILE))
                return 0;

        status = efi.query_variable_info(attributes, &storage_size,
                                         &remaining_size, &max_size);
        if (status != EFI_SUCCESS)
                return status;

        /*
         * Some firmware implementations refuse to boot if there's insufficient
         * space in the variable store. We account for that by refusing the
         * write if permitting it would reduce the available space to under
         * 5KB. This figure was provided by Samsung, so should be safe.
         */
        if ((remaining_size - size < EFI_MIN_RESERVE) &&
                !efi_no_storage_paranoia) {

                /*
                 * Triggering garbage collection may require that the firmware
                 * generate a real EFI_OUT_OF_RESOURCES error. We can force
                 * that by attempting to use more space than is available.
                 */
                unsigned long dummy_size = remaining_size + 1024;
                void *dummy = kzalloc(dummy_size, GFP_ATOMIC);

                if (!dummy)
                        return EFI_OUT_OF_RESOURCES;

                status = efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
                                          EFI_VARIABLE_NON_VOLATILE |
                                          EFI_VARIABLE_BOOTSERVICE_ACCESS |
                                          EFI_VARIABLE_RUNTIME_ACCESS,
                                          dummy_size, dummy);

                if (status == EFI_SUCCESS) {
                        /*
                         * This should have failed, so if it didn't make sure
                         * that we delete it...
                         */
                        efi.set_variable(efi_dummy_name, &EFI_DUMMY_GUID,
                                         EFI_VARIABLE_NON_VOLATILE |
                                         EFI_VARIABLE_BOOTSERVICE_ACCESS |
                                         EFI_VARIABLE_RUNTIME_ACCESS,
                                         0, dummy);
                }

                kfree(dummy);

                /*
                 * The runtime code may now have triggered a garbage collection
                 * run, so check the variable info again
                 */
                status = efi.query_variable_info(attributes, &storage_size,
                                                 &remaining_size, &max_size);

                if (status != EFI_SUCCESS)
                        return status;

                /*
                 * There still isn't enough room, so return an error

                 */
                if (remaining_size - size < EFI_MIN_RESERVE)
                        return EFI_OUT_OF_RESOURCES;
        }

        return EFI_SUCCESS;
}
EXPORT_SYMBOL_GPL(efi_query_variable_store);