[mirror_ubuntu-jammy-kernel.git] / arch / x86 / kernel / setup.c

/*
 *  Copyright (C) 1995  Linus Torvalds
 *
 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 *
 *  Memory region support
 *      David Parsons <orc@pell.chi.il.us>, July-August 1999
 *
 *  Added E820 sanitization routine (removes overlapping memory regions);
 *  Brian Moyle <bmoyle@mvista.com>, February 2001
 *
 * Moved CPU detection code to cpu/${cpu}.c
 *    Patrick Mochel <mochel@osdl.org>, March 2002
 *
 *  Provisions for empty E820 memory regions (reported by certain BIOSes).
 *  Alex Achenbach <xela@slit.de>, December 2002.
 *
 */

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

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/screen_info.h>
#include <linux/ioport.h>
#include <linux/acpi.h>
#include <linux/sfi.h>
#include <linux/apm_bios.h>
#include <linux/initrd.h>
#include <linux/memblock.h>
#include <linux/seq_file.h>
#include <linux/console.h>
#include <linux/root_dev.h>
#include <linux/highmem.h>
#include <linux/export.h>
#include <linux/efi.h>
#include <linux/init.h>
#include <linux/edd.h>
#include <linux/iscsi_ibft.h>
#include <linux/nodemask.h>
#include <linux/kexec.h>
#include <linux/dmi.h>
#include <linux/pfn.h>
#include <linux/pci.h>
#include <asm/pci-direct.h>
#include <linux/init_ohci1394_dma.h>
#include <linux/kvm_para.h>
#include <linux/dma-contiguous.h>
#include <xen/xen.h>
#include <uapi/linux/mount.h>

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/delay.h>

#include <linux/kallsyms.h>
#include <linux/cpufreq.h>
#include <linux/dma-mapping.h>
#include <linux/ctype.h>
#include <linux/uaccess.h>

#include <linux/percpu.h>
#include <linux/crash_dump.h>
#include <linux/tboot.h>
#include <linux/jiffies.h>
#include <linux/mem_encrypt.h>

#include <linux/usb/xhci-dbgp.h>
#include <video/edid.h>

#include <asm/mtrr.h>
#include <asm/apic.h>
#include <asm/realmode.h>
#include <asm/e820/api.h>
#include <asm/mpspec.h>
#include <asm/setup.h>
#include <asm/efi.h>
#include <asm/timer.h>
#include <asm/i8259.h>
#include <asm/sections.h>
#include <asm/io_apic.h>
#include <asm/ist.h>
#include <asm/setup_arch.h>
#include <asm/bios_ebda.h>
#include <asm/cacheflush.h>
#include <asm/processor.h>
#include <asm/bugs.h>
#include <asm/kasan.h>

#include <asm/vsyscall.h>
#include <asm/cpu.h>
#include <asm/desc.h>
#include <asm/dma.h>
#include <asm/iommu.h>
#include <asm/gart.h>
#include <asm/mmu_context.h>
#include <asm/proto.h>

#include <asm/paravirt.h>
#include <asm/hypervisor.h>
#include <asm/olpc_ofw.h>

#include <asm/percpu.h>
#include <asm/topology.h>
#include <asm/apicdef.h>
#include <asm/amd_nb.h>
#include <asm/mce.h>
#include <asm/alternative.h>
#include <asm/prom.h>
#include <asm/microcode.h>
#include <asm/kaslr.h>
#include <asm/unwind.h>

/*
 * max_low_pfn_mapped: highest direct mapped pfn under 4GB
 * max_pfn_mapped:     highest direct mapped pfn over 4GB
 *
 * The direct mapping only covers E820_TYPE_RAM regions, so the ranges and gaps are
 * represented by pfn_mapped
 */
unsigned long max_low_pfn_mapped;
unsigned long max_pfn_mapped;

#ifdef CONFIG_DMI
RESERVE_BRK(dmi_alloc, 65536);
#endif


static __initdata unsigned long _brk_start = (unsigned long)__brk_base;
unsigned long _brk_end = (unsigned long)__brk_base;

struct boot_params boot_params;

/*
 * Machine setup..
 */
static struct resource data_resource = {
        .name   = "Kernel data",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
};

static struct resource code_resource = {
        .name   = "Kernel code",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
};

static struct resource bss_resource = {
        .name   = "Kernel bss",
        .start  = 0,
        .end    = 0,
        .flags  = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM
};


#ifdef CONFIG_X86_32
/* cpu data as detected by the assembly code in head_32.S */
struct cpuinfo_x86 new_cpu_data;

/* common cpu data for all cpus */
struct cpuinfo_x86 boot_cpu_data __read_mostly;
EXPORT_SYMBOL(boot_cpu_data);

unsigned int def_to_bigsmp;

/* for MCA, but anyone else can use it if they want */
unsigned int machine_id;
unsigned int machine_submodel_id;
unsigned int BIOS_revision;

struct apm_info apm_info;
EXPORT_SYMBOL(apm_info);

#if defined(CONFIG_X86_SPEEDSTEP_SMI) || \
        defined(CONFIG_X86_SPEEDSTEP_SMI_MODULE)
struct ist_info ist_info;
EXPORT_SYMBOL(ist_info);
#else
struct ist_info ist_info;
#endif

#else
struct cpuinfo_x86 boot_cpu_data __read_mostly;
EXPORT_SYMBOL(boot_cpu_data);
#endif


#if !defined(CONFIG_X86_PAE) || defined(CONFIG_X86_64)
__visible unsigned long mmu_cr4_features __ro_after_init;
#else
__visible unsigned long mmu_cr4_features __ro_after_init = X86_CR4_PAE;
#endif

/* Boot loader ID and version as integers, for the benefit of proc_dointvec */
int bootloader_type, bootloader_version;

/*
 * Setup options
 */
struct screen_info screen_info;
EXPORT_SYMBOL(screen_info);
struct edid_info edid_info;
EXPORT_SYMBOL_GPL(edid_info);

extern int root_mountflags;

unsigned long saved_video_mode;

#define RAMDISK_IMAGE_START_MASK        0x07FF
#define RAMDISK_PROMPT_FLAG             0x8000
#define RAMDISK_LOAD_FLAG               0x4000

static char __initdata command_line[COMMAND_LINE_SIZE];
#ifdef CONFIG_CMDLINE_BOOL
static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
#endif

#if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
struct edd edd;
#ifdef CONFIG_EDD_MODULE
EXPORT_SYMBOL(edd);
#endif
/**
 * copy_edd() - Copy the BIOS EDD information
 *              from boot_params into a safe place.
 *
 */
static inline void __init copy_edd(void)
{
     memcpy(edd.mbr_signature, boot_params.edd_mbr_sig_buffer,
            sizeof(edd.mbr_signature));
     memcpy(edd.edd_info, boot_params.eddbuf, sizeof(edd.edd_info));
     edd.mbr_signature_nr = boot_params.edd_mbr_sig_buf_entries;
     edd.edd_info_nr = boot_params.eddbuf_entries;
}
#else
static inline void __init copy_edd(void)
{
}
#endif

void * __init extend_brk(size_t size, size_t align)
{
        size_t mask = align - 1;
        void *ret;

        BUG_ON(_brk_start == 0);
        BUG_ON(align & mask);

        _brk_end = (_brk_end + mask) & ~mask;
        BUG_ON((char *)(_brk_end + size) > __brk_limit);

        ret = (void *)_brk_end;
        _brk_end += size;

        memset(ret, 0, size);

        return ret;
}

#ifdef CONFIG_X86_32
static void __init cleanup_highmap(void)
{
}
#endif

static void __init reserve_brk(void)
{
        if (_brk_end > _brk_start)
                memblock_reserve(__pa_symbol(_brk_start),
                                 _brk_end - _brk_start);

        /* Mark brk area as locked down and no longer taking any
           new allocations */
        _brk_start = 0;
}

u64 relocated_ramdisk;

#ifdef CONFIG_BLK_DEV_INITRD

static u64 __init get_ramdisk_image(void)
{
        u64 ramdisk_image = boot_params.hdr.ramdisk_image;

        ramdisk_image |= (u64)boot_params.ext_ramdisk_image << 32;

        return ramdisk_image;
}
static u64 __init get_ramdisk_size(void)
{
        u64 ramdisk_size = boot_params.hdr.ramdisk_size;

        ramdisk_size |= (u64)boot_params.ext_ramdisk_size << 32;

        return ramdisk_size;
}

static void __init relocate_initrd(void)
{
        /* Assume only end is not page aligned */
        u64 ramdisk_image = get_ramdisk_image();
        u64 ramdisk_size  = get_ramdisk_size();
        u64 area_size     = PAGE_ALIGN(ramdisk_size);

        /* We need to move the initrd down into directly mapped mem */
        relocated_ramdisk = memblock_find_in_range(0, PFN_PHYS(max_pfn_mapped),
                                                   area_size, PAGE_SIZE);

        if (!relocated_ramdisk)
                panic("Cannot find place for new RAMDISK of size %lld\n",
                      ramdisk_size);

        /* Note: this includes all the mem currently occupied by
           the initrd, we rely on that fact to keep the data intact. */
        memblock_reserve(relocated_ramdisk, area_size);
        initrd_start = relocated_ramdisk + PAGE_OFFSET;
        initrd_end   = initrd_start + ramdisk_size;
        printk(KERN_INFO "Allocated new RAMDISK: [mem %#010llx-%#010llx]\n",
               relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);

        copy_from_early_mem((void *)initrd_start, ramdisk_image, ramdisk_size);

        printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
                " [mem %#010llx-%#010llx]\n",
                ramdisk_image, ramdisk_image + ramdisk_size - 1,
                relocated_ramdisk, relocated_ramdisk + ramdisk_size - 1);
}

static void __init early_reserve_initrd(void)
{
        /* Assume only end is not page aligned */
        u64 ramdisk_image = get_ramdisk_image();
        u64 ramdisk_size  = get_ramdisk_size();
        u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);

        if (!boot_params.hdr.type_of_loader ||
            !ramdisk_image || !ramdisk_size)
                return;         /* No initrd provided by bootloader */

        memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
}
static void __init reserve_initrd(void)
{
        /* Assume only end is not page aligned */
        u64 ramdisk_image = get_ramdisk_image();
        u64 ramdisk_size  = get_ramdisk_size();
        u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
        u64 mapped_size;

        if (!boot_params.hdr.type_of_loader ||
            !ramdisk_image || !ramdisk_size)
                return;         /* No initrd provided by bootloader */

        initrd_start = 0;

        mapped_size = memblock_mem_size(max_pfn_mapped);
        if (ramdisk_size >= (mapped_size>>1))
                panic("initrd too large to handle, "
                       "disabling initrd (%lld needed, %lld available)\n",
                       ramdisk_size, mapped_size>>1);

        printk(KERN_INFO "RAMDISK: [mem %#010llx-%#010llx]\n", ramdisk_image,
                        ramdisk_end - 1);

        if (pfn_range_is_mapped(PFN_DOWN(ramdisk_image),
                                PFN_DOWN(ramdisk_end))) {
                /* All are mapped, easy case */
                initrd_start = ramdisk_image + PAGE_OFFSET;
                initrd_end = initrd_start + ramdisk_size;
                return;
        }

        relocate_initrd();

        memblock_free(ramdisk_image, ramdisk_end - ramdisk_image);
}

#else
static void __init early_reserve_initrd(void)
{
}
static void __init reserve_initrd(void)
{
}
#endif /* CONFIG_BLK_DEV_INITRD */

static void __init parse_setup_data(void)
{
        struct setup_data *data;
        u64 pa_data, pa_next;

        pa_data = boot_params.hdr.setup_data;
        while (pa_data) {
                u32 data_len, data_type;

                data = early_memremap(pa_data, sizeof(*data));
                data_len = data->len + sizeof(struct setup_data);
                data_type = data->type;
                pa_next = data->next;
                early_memunmap(data, sizeof(*data));

                switch (data_type) {
                case SETUP_E820_EXT:
                        e820__memory_setup_extended(pa_data, data_len);
                        break;
                case SETUP_DTB:
                        add_dtb(pa_data);
                        break;
                case SETUP_EFI:
                        parse_efi_setup(pa_data, data_len);
                        break;
                default:
                        break;
                }
                pa_data = pa_next;
        }
}

static void __init memblock_x86_reserve_range_setup_data(void)
{
        struct setup_data *data;
        u64 pa_data;

        pa_data = boot_params.hdr.setup_data;
        while (pa_data) {
                data = early_memremap(pa_data, sizeof(*data));
                memblock_reserve(pa_data, sizeof(*data) + data->len);
                pa_data = data->next;
                early_memunmap(data, sizeof(*data));
        }
}

/*
 * --------- Crashkernel reservation ------------------------------
 */

#ifdef CONFIG_KEXEC_CORE

/* 16M alignment for crash kernel regions */
#define CRASH_ALIGN             (16 << 20)

/*
 * Keep the crash kernel below this limit.  On 32 bits earlier kernels
 * would limit the kernel to the low 512 MiB due to mapping restrictions.
 * On 64bit, old kexec-tools need to under 896MiB.
 */
#ifdef CONFIG_X86_32
# define CRASH_ADDR_LOW_MAX     (512 << 20)
# define CRASH_ADDR_HIGH_MAX    (512 << 20)
#else
# define CRASH_ADDR_LOW_MAX     (896UL << 20)
# define CRASH_ADDR_HIGH_MAX    MAXMEM
#endif

static int __init reserve_crashkernel_low(void)
{
#ifdef CONFIG_X86_64
        unsigned long long base, low_base = 0, low_size = 0;
        unsigned long total_low_mem;
        int ret;

        total_low_mem = memblock_mem_size(1UL << (32 - PAGE_SHIFT));

        /* crashkernel=Y,low */
        ret = parse_crashkernel_low(boot_command_line, total_low_mem, &low_size, &base);
        if (ret) {
                /*
                 * two parts from lib/swiotlb.c:
                 * -swiotlb size: user-specified with swiotlb= or default.
                 *
                 * -swiotlb overflow buffer: now hardcoded to 32k. We round it
                 * to 8M for other buffers that may need to stay low too. Also
                 * make sure we allocate enough extra low memory so that we
                 * don't run out of DMA buffers for 32-bit devices.
                 */
                low_size = max(swiotlb_size_or_default() + (8UL << 20), 256UL << 20);
        } else {
                /* passed with crashkernel=0,low ? */
                if (!low_size)
                        return 0;
        }

        low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
        if (!low_base) {
                pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
                       (unsigned long)(low_size >> 20));
                return -ENOMEM;
        }

        ret = memblock_reserve(low_base, low_size);
        if (ret) {
                pr_err("%s: Error reserving crashkernel low memblock.\n", __func__);
                return ret;
        }

        pr_info("Reserving %ldMB of low memory at %ldMB for crashkernel (System low RAM: %ldMB)\n",
                (unsigned long)(low_size >> 20),
                (unsigned long)(low_base >> 20),
                (unsigned long)(total_low_mem >> 20));

        crashk_low_res.start = low_base;
        crashk_low_res.end   = low_base + low_size - 1;
        insert_resource(&iomem_resource, &crashk_low_res);
#endif
        return 0;
}

static void __init reserve_crashkernel(void)
{
        unsigned long long crash_size, crash_base, total_mem;
        bool high = false;
        int ret;

        total_mem = memblock_phys_mem_size();

        /* crashkernel=XM */
        ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
        if (ret != 0 || crash_size <= 0) {
                /* crashkernel=X,high */
                ret = parse_crashkernel_high(boot_command_line, total_mem,
                                             &crash_size, &crash_base);
                if (ret != 0 || crash_size <= 0)
                        return;
                high = true;
        }

        if (xen_pv_domain()) {
                pr_info("Ignoring crashkernel for a Xen PV domain\n");
                return;
        }

        /* 0 means: find the address automatically */
        if (crash_base <= 0) {
                /*
                 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory,
                 * as old kexec-tools loads bzImage below that, unless
                 * "crashkernel=size[KMG],high" is specified.
                 */
                crash_base = memblock_find_in_range(CRASH_ALIGN,
                                                    high ? CRASH_ADDR_HIGH_MAX
                                                         : CRASH_ADDR_LOW_MAX,
                                                    crash_size, CRASH_ALIGN);
                if (!crash_base) {
                        pr_info("crashkernel reservation failed - No suitable area found.\n");
                        return;
                }

        } else {
                unsigned long long start;

                start = memblock_find_in_range(crash_base,
                                               crash_base + crash_size,
                                               crash_size, 1 << 20);
                if (start != crash_base) {
                        pr_info("crashkernel reservation failed - memory is in use.\n");
                        return;
                }
        }
        ret = memblock_reserve(crash_base, crash_size);
        if (ret) {
                pr_err("%s: Error reserving crashkernel memblock.\n", __func__);
                return;
        }

        if (crash_base >= (1ULL << 32) && reserve_crashkernel_low()) {
                memblock_free(crash_base, crash_size);
                return;
        }

        pr_info("Reserving %ldMB of memory at %ldMB for crashkernel (System RAM: %ldMB)\n",
                (unsigned long)(crash_size >> 20),
                (unsigned long)(crash_base >> 20),
                (unsigned long)(total_mem >> 20));

        crashk_res.start = crash_base;
        crashk_res.end   = crash_base + crash_size - 1;
        insert_resource(&iomem_resource, &crashk_res);
}
#else
static void __init reserve_crashkernel(void)
{
}
#endif

static struct resource standard_io_resources[] = {
        { .name = "dma1", .start = 0x00, .end = 0x1f,
                .flags = IORESOURCE_BUSY | IORESOURCE_IO },
        { .name = "pic1", .start = 0x20, .end = 0x21,
                .flags = IORESOURCE_BUSY | IORESOURCE_IO },
        { .name = "timer0", .start = 0x40, .end = 0x43,
                .flags = IORESOURCE_BUSY | IORESOURCE_IO },
        { .name = "timer1", .start = 0x50, .end = 0x53,
                .flags = IORESOURCE_BUSY | IORESOURCE_IO },
        { .name = "keyboard", .start = 0x60, .end = 0x60,
                .flags = IORESOURCE_BUSY | IORESOURCE_IO },
        { .name = "keyboard", .start = 0x64, .end = 0x64,
                .flags = IORESOURCE_BUSY | IORESOURCE_IO },
        { .name = "dma page reg", .start = 0x80, .end = 0x8f,
                .flags = IORESOURCE_BUSY | IORESOURCE_IO },
        { .name = "pic2", .start = 0xa0, .end = 0xa1,
                .flags = IORESOURCE_BUSY | IORESOURCE_IO },
        { .name = "dma2", .start = 0xc0, .end = 0xdf,
                .flags = IORESOURCE_BUSY | IORESOURCE_IO },
        { .name = "fpu", .start = 0xf0, .end = 0xff,
                .flags = IORESOURCE_BUSY | IORESOURCE_IO }
};

void __init reserve_standard_io_resources(void)
{
        int i;

        /* request I/O space for devices used on all i[345]86 PCs */
        for (i = 0; i < ARRAY_SIZE(standard_io_resources); i++)
                request_resource(&ioport_resource, &standard_io_resources[i]);

}

static __init void reserve_ibft_region(void)
{
        unsigned long addr, size = 0;

        addr = find_ibft_region(&size);

        if (size)
                memblock_reserve(addr, size);
}

static bool __init snb_gfx_workaround_needed(void)
{
#ifdef CONFIG_PCI
        int i;
        u16 vendor, devid;
        static const __initconst u16 snb_ids[] = {
                0x0102,
                0x0112,
                0x0122,
                0x0106,
                0x0116,
                0x0126,
                0x010a,
        };

        /* Assume no if something weird is going on with PCI */
        if (!early_pci_allowed())
                return false;

        vendor = read_pci_config_16(0, 2, 0, PCI_VENDOR_ID);
        if (vendor != 0x8086)
                return false;

        devid = read_pci_config_16(0, 2, 0, PCI_DEVICE_ID);
        for (i = 0; i < ARRAY_SIZE(snb_ids); i++)
                if (devid == snb_ids[i])
                        return true;
#endif

        return false;
}

/*
 * Sandy Bridge graphics has trouble with certain ranges, exclude
 * them from allocation.
 */
static void __init trim_snb_memory(void)
{
        static const __initconst unsigned long bad_pages[] = {
                0x20050000,
                0x20110000,
                0x20130000,
                0x20138000,
                0x40004000,
        };
        int i;

        if (!snb_gfx_workaround_needed())
                return;

        printk(KERN_DEBUG "reserving inaccessible SNB gfx pages\n");

        /*
         * Reserve all memory below the 1 MB mark that has not
         * already been reserved.
         */
        memblock_reserve(0, 1<<20);
        
        for (i = 0; i < ARRAY_SIZE(bad_pages); i++) {
                if (memblock_reserve(bad_pages[i], PAGE_SIZE))
                        printk(KERN_WARNING "failed to reserve 0x%08lx\n",
                               bad_pages[i]);
        }
}

/*
 * Here we put platform-specific memory range workarounds, i.e.
 * memory known to be corrupt or otherwise in need to be reserved on
 * specific platforms.
 *
 * If this gets used more widely it could use a real dispatch mechanism.
 */
static void __init trim_platform_memory_ranges(void)
{
        trim_snb_memory();
}

static void __init trim_bios_range(void)
{
        /*
         * A special case is the first 4Kb of memory;
         * This is a BIOS owned area, not kernel ram, but generally
         * not listed as such in the E820 table.
         *
         * This typically reserves additional memory (64KiB by default)
         * since some BIOSes are known to corrupt low memory.  See the
         * Kconfig help text for X86_RESERVE_LOW.
         */
        e820__range_update(0, PAGE_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED);

        /*
         * special case: Some BIOSen report the PC BIOS
         * area (640->1Mb) as ram even though it is not.
         * take them out.
         */
        e820__range_remove(BIOS_BEGIN, BIOS_END - BIOS_BEGIN, E820_TYPE_RAM, 1);

        e820__update_table(e820_table);
}

/* called before trim_bios_range() to spare extra sanitize */
static void __init e820_add_kernel_range(void)
{
        u64 start = __pa_symbol(_text);
        u64 size = __pa_symbol(_end) - start;

        /*
         * Complain if .text .data and .bss are not marked as E820_TYPE_RAM and
         * attempt to fix it by adding the range. We may have a confused BIOS,
         * or the user may have used memmap=exactmap or memmap=xxM$yyM to
         * exclude kernel range. If we really are running on top non-RAM,
         * we will crash later anyways.
         */
        if (e820__mapped_all(start, start + size, E820_TYPE_RAM))
                return;

        pr_warn(".text .data .bss are not marked as E820_TYPE_RAM!\n");
        e820__range_remove(start, size, E820_TYPE_RAM, 0);
        e820__range_add(start, size, E820_TYPE_RAM);
}

static unsigned reserve_low = CONFIG_X86_RESERVE_LOW << 10;

static int __init parse_reservelow(char *p)
{
        unsigned long long size;

        if (!p)
                return -EINVAL;

        size = memparse(p, &p);

        if (size < 4096)
                size = 4096;

        if (size > 640*1024)
                size = 640*1024;

        reserve_low = size;

        return 0;
}

early_param("reservelow", parse_reservelow);

static void __init trim_low_memory_range(void)
{
        memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE));
}
        
/*
 * Dump out kernel offset information on panic.
 */
static int
dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
{
        if (kaslr_enabled()) {
                pr_emerg("Kernel Offset: 0x%lx from 0x%lx (relocation range: 0x%lx-0x%lx)\n",
                         kaslr_offset(),
                         __START_KERNEL,
                         __START_KERNEL_map,
                         MODULES_VADDR-1);
        } else {
                pr_emerg("Kernel Offset: disabled\n");
        }

        return 0;
}

/*
 * Determine if we were loaded by an EFI loader.  If so, then we have also been
 * passed the efi memmap, systab, etc., so we should use these data structures
 * for initialization.  Note, the efi init code path is determined by the
 * global efi_enabled. This allows the same kernel image to be used on existing
 * systems (with a traditional BIOS) as well as on EFI systems.
 */
/*
 * setup_arch - architecture-specific boot-time initializations
 *
 * Note: On x86_64, fixmaps are ready for use even before this is called.
 */

void __init setup_arch(char **cmdline_p)
{
        memblock_reserve(__pa_symbol(_text),
                         (unsigned long)__bss_stop - (unsigned long)_text);

        /*
         * Make sure page 0 is always reserved because on systems with
         * L1TF its contents can be leaked to user processes.
         */
        memblock_reserve(0, PAGE_SIZE);

        early_reserve_initrd();

        /*
         * At this point everything still needed from the boot loader
         * or BIOS or kernel text should be early reserved or marked not
         * RAM in e820. All other memory is free game.
         */

#ifdef CONFIG_X86_32
        memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));

        /*
         * copy kernel address range established so far and switch
         * to the proper swapper page table
         */
        clone_pgd_range(swapper_pg_dir     + KERNEL_PGD_BOUNDARY,
                        initial_page_table + KERNEL_PGD_BOUNDARY,
                        KERNEL_PGD_PTRS);

        load_cr3(swapper_pg_dir);
        /*
         * Note: Quark X1000 CPUs advertise PGE incorrectly and require
         * a cr3 based tlb flush, so the following __flush_tlb_all()
         * will not flush anything because the cpu quirk which clears
         * X86_FEATURE_PGE has not been invoked yet. Though due to the
         * load_cr3() above the TLB has been flushed already. The
         * quirk is invoked before subsequent calls to __flush_tlb_all()
         * so proper operation is guaranteed.
         */
        __flush_tlb_all();
#else
        printk(KERN_INFO "Command line: %s\n", boot_command_line);
        boot_cpu_data.x86_phys_bits = MAX_PHYSMEM_BITS;
#endif

        /*
         * If we have OLPC OFW, we might end up relocating the fixmap due to
         * reserve_top(), so do this before touching the ioremap area.
         */
        olpc_ofw_detect();

        idt_setup_early_traps();
        early_cpu_init();
        arch_init_ideal_nops();
        jump_label_init();
        early_ioremap_init();

        setup_olpc_ofw_pgd();

        ROOT_DEV = old_decode_dev(boot_params.hdr.root_dev);
        screen_info = boot_params.screen_info;
        edid_info = boot_params.edid_info;
#ifdef CONFIG_X86_32
        apm_info.bios = boot_params.apm_bios_info;
        ist_info = boot_params.ist_info;
#endif
        saved_video_mode = boot_params.hdr.vid_mode;
        bootloader_type = boot_params.hdr.type_of_loader;
        if ((bootloader_type >> 4) == 0xe) {
                bootloader_type &= 0xf;
                bootloader_type |= (boot_params.hdr.ext_loader_type+0x10) << 4;
        }
        bootloader_version  = bootloader_type & 0xf;
        bootloader_version |= boot_params.hdr.ext_loader_ver << 4;

#ifdef CONFIG_BLK_DEV_RAM
        rd_image_start = boot_params.hdr.ram_size & RAMDISK_IMAGE_START_MASK;
        rd_prompt = ((boot_params.hdr.ram_size & RAMDISK_PROMPT_FLAG) != 0);
        rd_doload = ((boot_params.hdr.ram_size & RAMDISK_LOAD_FLAG) != 0);
#endif
#ifdef CONFIG_EFI
        if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
                     EFI32_LOADER_SIGNATURE, 4)) {
                set_bit(EFI_BOOT, &efi.flags);
        } else if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
                     EFI64_LOADER_SIGNATURE, 4)) {
                set_bit(EFI_BOOT, &efi.flags);
                set_bit(EFI_64BIT, &efi.flags);
        }
#endif

        x86_init.oem.arch_setup();

        iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1;
        e820__memory_setup();
        parse_setup_data();

        copy_edd();

        if (!boot_params.hdr.root_flags)
                root_mountflags &= ~MS_RDONLY;
        init_mm.start_code = (unsigned long) _text;
        init_mm.end_code = (unsigned long) _etext;
        init_mm.end_data = (unsigned long) _edata;
        init_mm.brk = _brk_end;

        mpx_mm_init(&init_mm);

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

#ifdef CONFIG_CMDLINE_BOOL
#ifdef CONFIG_CMDLINE_OVERRIDE
        strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
#else
        if (builtin_cmdline[0]) {
                /* append boot loader cmdline to builtin */
                strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
                strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
                strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
        }
#endif
#endif

        strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
        *cmdline_p = command_line;

        /*
         * x86_configure_nx() is called before parse_early_param() to detect
         * whether hardware doesn't support NX (so that the early EHCI debug
         * console setup can safely call set_fixmap()). It may then be called
         * again from within noexec_setup() during parsing early parameters
         * to honor the respective command line option.
         */
        x86_configure_nx();

        parse_early_param();

        if (efi_enabled(EFI_BOOT))
                efi_memblock_x86_reserve_range();
#ifdef CONFIG_MEMORY_HOTPLUG
        /*
         * Memory used by the kernel cannot be hot-removed because Linux
         * cannot migrate the kernel pages. When memory hotplug is
         * enabled, we should prevent memblock from allocating memory
         * for the kernel.
         *
         * ACPI SRAT records all hotpluggable memory ranges. But before
         * SRAT is parsed, we don't know about it.
         *
         * The kernel image is loaded into memory at very early time. We
         * cannot prevent this anyway. So on NUMA system, we set any
         * node the kernel resides in as un-hotpluggable.
         *
         * Since on modern servers, one node could have double-digit
         * gigabytes memory, we can assume the memory around the kernel
         * image is also un-hotpluggable. So before SRAT is parsed, just
         * allocate memory near the kernel image to try the best to keep
         * the kernel away from hotpluggable memory.
         */
        if (movable_node_is_enabled())
                memblock_set_bottom_up(true);
#endif

        x86_report_nx();

        /* after early param, so could get panic from serial */
        memblock_x86_reserve_range_setup_data();

        if (acpi_mps_check()) {
#ifdef CONFIG_X86_LOCAL_APIC
                disable_apic = 1;
#endif
                setup_clear_cpu_cap(X86_FEATURE_APIC);
        }

        e820__reserve_setup_data();
        e820__finish_early_params();

        if (efi_enabled(EFI_BOOT))
                efi_init();

        dmi_scan_machine();
        dmi_memdev_walk();
        dmi_set_dump_stack_arch_desc();

        /*
         * VMware detection requires dmi to be available, so this
         * needs to be done after dmi_scan_machine(), for the boot CPU.
         */
        init_hypervisor_platform();

        tsc_early_init();
        x86_init.resources.probe_roms();

        /* after parse_early_param, so could debug it */
        insert_resource(&iomem_resource, &code_resource);
        insert_resource(&iomem_resource, &data_resource);
        insert_resource(&iomem_resource, &bss_resource);

        e820_add_kernel_range();
        trim_bios_range();
#ifdef CONFIG_X86_32
        if (ppro_with_ram_bug()) {
                e820__range_update(0x70000000ULL, 0x40000ULL, E820_TYPE_RAM,
                                  E820_TYPE_RESERVED);
                e820__update_table(e820_table);
                printk(KERN_INFO "fixed physical RAM map:\n");
                e820__print_table("bad_ppro");
        }
#else
        early_gart_iommu_check();
#endif

        /*
         * partially used pages are not usable - thus
         * we are rounding upwards:
         */
        max_pfn = e820__end_of_ram_pfn();

        /* update e820 for memory not covered by WB MTRRs */
        mtrr_bp_init();
        if (mtrr_trim_uncached_memory(max_pfn))
                max_pfn = e820__end_of_ram_pfn();

        max_possible_pfn = max_pfn;

        /*
         * This call is required when the CPU does not support PAT. If
         * mtrr_bp_init() invoked it already via pat_init() the call has no
         * effect.
         */
        init_cache_modes();

        /*
         * Define random base addresses for memory sections after max_pfn is
         * defined and before each memory section base is used.
         */
        kernel_randomize_memory();

#ifdef CONFIG_X86_32
        /* max_low_pfn get updated here */
        find_low_pfn_range();
#else
        check_x2apic();

        /* How many end-of-memory variables you have, grandma! */
        /* need this before calling reserve_initrd */
        if (max_pfn > (1UL<<(32 - PAGE_SHIFT)))
                max_low_pfn = e820__end_of_low_ram_pfn();
        else
                max_low_pfn = max_pfn;

        high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
#endif

        /*
         * Find and reserve possible boot-time SMP configuration:
         */
        find_smp_config();

        reserve_ibft_region();

        early_alloc_pgt_buf();

        /*
         * Need to conclude brk, before e820__memblock_setup()
         *  it could use memblock_find_in_range, could overlap with
         *  brk area.
         */
        reserve_brk();

        cleanup_highmap();

        memblock_set_current_limit(ISA_END_ADDRESS);
        e820__memblock_setup();

        reserve_bios_regions();

        if (efi_enabled(EFI_MEMMAP)) {
                efi_fake_memmap();
                efi_find_mirror();
                efi_esrt_init();

                /*
                 * The EFI specification says that boot service code won't be
                 * called after ExitBootServices(). This is, in fact, a lie.
                 */
                efi_reserve_boot_services();
        }

        /* preallocate 4k for mptable mpc */
        e820__memblock_alloc_reserved_mpc_new();

#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
        setup_bios_corruption_check();
#endif

#ifdef CONFIG_X86_32
        printk(KERN_DEBUG "initial memory mapped: [mem 0x00000000-%#010lx]\n",
                        (max_pfn_mapped<<PAGE_SHIFT) - 1);
#endif

        reserve_real_mode();

        trim_platform_memory_ranges();
        trim_low_memory_range();

        init_mem_mapping();

        idt_setup_early_pf();

        /*
         * Update mmu_cr4_features (and, indirectly, trampoline_cr4_features)
         * with the current CR4 value.  This may not be necessary, but
         * auditing all the early-boot CR4 manipulation would be needed to
         * rule it out.
         *
         * Mask off features that don't work outside long mode (just
         * PCIDE for now).
         */
        mmu_cr4_features = __read_cr4() & ~X86_CR4_PCIDE;

        memblock_set_current_limit(get_max_mapped());

        /*
         * NOTE: On x86-32, only from this point on, fixmaps are ready for use.
         */

#ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
        if (init_ohci1394_dma_early)
                init_ohci1394_dma_on_all_controllers();
#endif
        /* Allocate bigger log buffer */
        setup_log_buf(1);

        if (efi_enabled(EFI_BOOT)) {
                switch (boot_params.secure_boot) {
                case efi_secureboot_mode_disabled:
                        pr_info("Secure boot disabled\n");
                        break;
                case efi_secureboot_mode_enabled:
                        pr_info("Secure boot enabled\n");
                        break;
                default:
                        pr_info("Secure boot could not be determined\n");
                        break;
                }
        }

        reserve_initrd();

        acpi_table_upgrade();

        vsmp_init();

        io_delay_init();

        early_platform_quirks();

        /*
         * Parse the ACPI tables for possible boot-time SMP configuration.
         */
        acpi_boot_table_init();

        early_acpi_boot_init();

        initmem_init();
        dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);

        /*
         * Reserve memory for crash kernel after SRAT is parsed so that it
         * won't consume hotpluggable memory.
         */
        reserve_crashkernel();

        memblock_find_dma_reserve();

        if (!early_xdbc_setup_hardware())
                early_xdbc_register_console();

        x86_init.paging.pagetable_init();

        kasan_init();

        /*
         * Sync back kernel address range.
         *
         * FIXME: Can the later sync in setup_cpu_entry_areas() replace
         * this call?
         */
        sync_initial_page_table();

        tboot_probe();

        map_vsyscall();

        generic_apic_probe();

        early_quirks();

        /*
         * Read APIC and some other early information from ACPI tables.
         */
        acpi_boot_init();
        sfi_init();
        x86_dtb_init();

        /*
         * get boot-time SMP configuration:
         */
        get_smp_config();

        /*
         * Systems w/o ACPI and mptables might not have it mapped the local
         * APIC yet, but prefill_possible_map() might need to access it.
         */
        init_apic_mappings();

        prefill_possible_map();

        init_cpu_to_node();

        io_apic_init_mappings();

        x86_init.hyper.guest_late_init();

        e820__reserve_resources();
        e820__register_nosave_regions(max_pfn);

        x86_init.resources.reserve_resources();

        e820__setup_pci_gap();

#ifdef CONFIG_VT
#if defined(CONFIG_VGA_CONSOLE)
        if (!efi_enabled(EFI_BOOT) || (efi_mem_type(0xa0000) != EFI_CONVENTIONAL_MEMORY))
                conswitchp = &vga_con;
#elif defined(CONFIG_DUMMY_CONSOLE)
        conswitchp = &dummy_con;
#endif
#endif
        x86_init.oem.banner();

        x86_init.timers.wallclock_init();

        mcheck_init();

        register_refined_jiffies(CLOCK_TICK_RATE);

#ifdef CONFIG_EFI
        if (efi_enabled(EFI_BOOT))
                efi_apply_memmap_quirks();
#endif

        unwind_init();
}

#ifdef CONFIG_X86_32

static struct resource video_ram_resource = {
        .name   = "Video RAM area",
        .start  = 0xa0000,
        .end    = 0xbffff,
        .flags  = IORESOURCE_BUSY | IORESOURCE_MEM
};

void __init i386_reserve_resources(void)
{
        request_resource(&iomem_resource, &video_ram_resource);
        reserve_standard_io_resources();
}

#endif /* CONFIG_X86_32 */

static struct notifier_block kernel_offset_notifier = {
        .notifier_call = dump_kernel_offset
};

static int __init register_kernel_offset_dumper(void)
{
        atomic_notifier_chain_register(&panic_notifier_list,
                                        &kernel_offset_notifier);
        return 0;
}
__initcall(register_kernel_offset_dumper);