// SPDX-License-Identifier: GPL-2.0
/*
 *      Intel Multiprocessor Specification 1.1 and 1.4
 *      compliant MP-table parsing routines.
 *
 *      (c) 1995 Alan Cox, Building #3 <alan@lxorguk.ukuu.org.uk>
 *      (c) 1998, 1999, 2000, 2009 Ingo Molnar <mingo@redhat.com>
 *      (c) 2008 Alexey Starikovskiy <astarikovskiy@suse.de>
 */

#include <linux/mm.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/memblock.h>
#include <linux/kernel_stat.h>
#include <linux/mc146818rtc.h>
#include <linux/bitops.h>
#include <linux/acpi.h>
#include <linux/smp.h>
#include <linux/pci.h>

#include <asm/i8259.h>
#include <asm/io_apic.h>
#include <asm/acpi.h>
#include <asm/irqdomain.h>
#include <asm/mtrr.h>
#include <asm/mpspec.h>
#include <asm/proto.h>
#include <asm/bios_ebda.h>
#include <asm/e820/api.h>
#include <asm/setup.h>
#include <asm/smp.h>

#include <asm/apic.h>
/*
 * Checksum an MP configuration block.
 */

static unsigned int num_procs __initdata;

static int __init mpf_checksum(unsigned char *mp, int len)
{
        int sum = 0;

        while (len--)
                sum += *mp++;

        return sum & 0xFF;
}

static void __init MP_processor_info(struct mpc_cpu *m)
{
        char *bootup_cpu = "";

        topology_register_apic(m->apicid, CPU_ACPIID_INVALID, m->cpuflag & CPU_ENABLED);
        if (!(m->cpuflag & CPU_ENABLED))
                return;

        if (m->cpuflag & CPU_BOOTPROCESSOR)
                bootup_cpu = " (Bootup-CPU)";

        pr_info("Processor #%d%s\n", m->apicid, bootup_cpu);
        num_procs++;
}

#ifdef CONFIG_X86_IO_APIC
static void __init mpc_oem_bus_info(struct mpc_bus *m, char *str)
{
        memcpy(str, m->bustype, 6);
        str[6] = 0;
        apic_pr_verbose("Bus #%d is %s\n", m->busid, str);
}

static void __init MP_bus_info(struct mpc_bus *m)
{
        char str[7];

        mpc_oem_bus_info(m, str);

#if MAX_MP_BUSSES < 256
        if (m->busid >= MAX_MP_BUSSES) {
                pr_warn("MP table busid value (%d) for bustype %s is too large, max. supported is %d\n",
                        m->busid, str, MAX_MP_BUSSES - 1);
                return;
        }
#endif

        set_bit(m->busid, mp_bus_not_pci);
        if (strncmp(str, BUSTYPE_ISA, sizeof(BUSTYPE_ISA) - 1) == 0) {
#ifdef CONFIG_EISA
                mp_bus_id_to_type[m->busid] = MP_BUS_ISA;
#endif
        } else if (strncmp(str, BUSTYPE_PCI, sizeof(BUSTYPE_PCI) - 1) == 0) {
                clear_bit(m->busid, mp_bus_not_pci);
#ifdef CONFIG_EISA
                mp_bus_id_to_type[m->busid] = MP_BUS_PCI;
        } else if (strncmp(str, BUSTYPE_EISA, sizeof(BUSTYPE_EISA) - 1) == 0) {
                mp_bus_id_to_type[m->busid] = MP_BUS_EISA;
#endif
        } else
                pr_warn("Unknown bustype %s - ignoring\n", str);
}

static void __init MP_ioapic_info(struct mpc_ioapic *m)
{
        struct ioapic_domain_cfg cfg = {
                .type = IOAPIC_DOMAIN_LEGACY,
                .ops = &mp_ioapic_irqdomain_ops,
        };

        if (m->flags & MPC_APIC_USABLE)
                mp_register_ioapic(m->apicid, m->apicaddr, gsi_top, &cfg);
}

static void __init print_mp_irq_info(struct mpc_intsrc *mp_irq)
{
        apic_printk(APIC_VERBOSE,
                "Int: type %d, pol %d, trig %d, bus %02x, IRQ %02x, APIC ID %x, APIC INT %02x\n",
                mp_irq->irqtype, mp_irq->irqflag & 3,
                (mp_irq->irqflag >> 2) & 3, mp_irq->srcbus,
                mp_irq->srcbusirq, mp_irq->dstapic, mp_irq->dstirq);
}

#else /* CONFIG_X86_IO_APIC */
static inline void __init MP_bus_info(struct mpc_bus *m) {}
static inline void __init MP_ioapic_info(struct mpc_ioapic *m) {}
#endif /* CONFIG_X86_IO_APIC */

static void __init MP_lintsrc_info(struct mpc_lintsrc *m)
{
        apic_printk(APIC_VERBOSE,
                "Lint: type %d, pol %d, trig %d, bus %02x, IRQ %02x, APIC ID %x, APIC LINT %02x\n",
                m->irqtype, m->irqflag & 3, (m->irqflag >> 2) & 3, m->srcbusid,
                m->srcbusirq, m->destapic, m->destapiclint);
}

/*
 * Read/parse the MPC
 */
static int __init smp_check_mpc(struct mpc_table *mpc, char *oem, char *str)
{

        if (memcmp(mpc->signature, MPC_SIGNATURE, 4)) {
                pr_err("MPTABLE: bad signature [%c%c%c%c]!\n",
                       mpc->signature[0], mpc->signature[1],
                       mpc->signature[2], mpc->signature[3]);
                return 0;
        }
        if (mpf_checksum((unsigned char *)mpc, mpc->length)) {
                pr_err("MPTABLE: checksum error!\n");
                return 0;
        }
        if (mpc->spec != 0x01 && mpc->spec != 0x04) {
                pr_err("MPTABLE: bad table version (%d)!!\n", mpc->spec);
                return 0;
        }
        if (!mpc->lapic) {
                pr_err("MPTABLE: null local APIC address!\n");
                return 0;
        }
        memcpy(oem, mpc->oem, 8);
        oem[8] = 0;
        pr_info("MPTABLE: OEM ID: %s\n", oem);

        memcpy(str, mpc->productid, 12);
        str[12] = 0;

        pr_info("MPTABLE: Product ID: %s\n", str);

        pr_info("MPTABLE: APIC at: 0x%X\n", mpc->lapic);

        return 1;
}

static void skip_entry(unsigned char **ptr, int *count, int size)
{
        *ptr += size;
        *count += size;
}

static void __init smp_dump_mptable(struct mpc_table *mpc, unsigned char *mpt)
{
        pr_err("Your mptable is wrong, contact your HW vendor!\n");
        pr_cont("type %x\n", *mpt);
        print_hex_dump(KERN_ERR, "  ", DUMP_PREFIX_ADDRESS, 16,
                        1, mpc, mpc->length, 1);
}

static int __init smp_read_mpc(struct mpc_table *mpc, unsigned early)
{
        char str[16];
        char oem[10];

        int count = sizeof(*mpc);
        unsigned char *mpt = ((unsigned char *)mpc) + count;

        if (!smp_check_mpc(mpc, oem, str))
                return 0;

        if (early) {
                /* Initialize the lapic mapping */
                if (!acpi_lapic)
                        register_lapic_address(mpc->lapic);
                return 1;
        }

        /* Now process the configuration blocks. */
        while (count < mpc->length) {
                switch (*mpt) {
                case MP_PROCESSOR:
                        /* ACPI may have already provided this data */
                        if (!acpi_lapic)
                                MP_processor_info((struct mpc_cpu *)mpt);
                        skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
                        break;
                case MP_BUS:
                        MP_bus_info((struct mpc_bus *)mpt);
                        skip_entry(&mpt, &count, sizeof(struct mpc_bus));
                        break;
                case MP_IOAPIC:
                        MP_ioapic_info((struct mpc_ioapic *)mpt);
                        skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
                        break;
                case MP_INTSRC:
                        mp_save_irq((struct mpc_intsrc *)mpt);
                        skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
                        break;
                case MP_LINTSRC:
                        MP_lintsrc_info((struct mpc_lintsrc *)mpt);
                        skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
                        break;
                default:
                        /* wrong mptable */
                        smp_dump_mptable(mpc, mpt);
                        count = mpc->length;
                        break;
                }
        }

        if (!num_procs && !acpi_lapic)
                pr_err("MPTABLE: no processors registered!\n");
        return num_procs || acpi_lapic;
}

#ifdef CONFIG_X86_IO_APIC

static int __init ELCR_trigger(unsigned int irq)
{
        unsigned int port;

        port = PIC_ELCR1 + (irq >> 3);
        return (inb(port) >> (irq & 7)) & 1;
}

static void __init construct_default_ioirq_mptable(int mpc_default_type)
{
        struct mpc_intsrc intsrc;
        int i;
        int ELCR_fallback = 0;

        intsrc.type = MP_INTSRC;
        intsrc.irqflag = MP_IRQTRIG_DEFAULT | MP_IRQPOL_DEFAULT;
        intsrc.srcbus = 0;
        intsrc.dstapic = mpc_ioapic_id(0);

        intsrc.irqtype = mp_INT;

        /*
         *  If true, we have an ISA/PCI system with no IRQ entries
         *  in the MP table. To prevent the PCI interrupts from being set up
         *  incorrectly, we try to use the ELCR. The sanity check to see if
         *  there is good ELCR data is very simple - IRQ0, 1, 2 and 13 can
         *  never be level sensitive, so we simply see if the ELCR agrees.
         *  If it does, we assume it's valid.
         */
        if (mpc_default_type == 5) {
                pr_info("ISA/PCI bus type with no IRQ information... falling back to ELCR\n");

                if (ELCR_trigger(0) || ELCR_trigger(1) || ELCR_trigger(2) ||
                    ELCR_trigger(13))
                        pr_err("ELCR contains invalid data... not using ELCR\n");
                else {
                        pr_info("Using ELCR to identify PCI interrupts\n");
                        ELCR_fallback = 1;
                }
        }

        for (i = 0; i < 16; i++) {
                switch (mpc_default_type) {
                case 2:
                        if (i == 0 || i == 13)
                                continue;       /* IRQ0 & IRQ13 not connected */
                        fallthrough;
                default:
                        if (i == 2)
                                continue;       /* IRQ2 is never connected */
                }

                if (ELCR_fallback) {
                        /*
                         *  If the ELCR indicates a level-sensitive interrupt, we
                         *  copy that information over to the MP table in the
                         *  irqflag field (level sensitive, active high polarity).
                         */
                        if (ELCR_trigger(i)) {
                                intsrc.irqflag = MP_IRQTRIG_LEVEL |
                                                 MP_IRQPOL_ACTIVE_HIGH;
                        } else {
                                intsrc.irqflag = MP_IRQTRIG_DEFAULT |
                                                 MP_IRQPOL_DEFAULT;
                        }
                }

                intsrc.srcbusirq = i;
                intsrc.dstirq = i ? i : 2;      /* IRQ0 to INTIN2 */
                mp_save_irq(&intsrc);
        }

        intsrc.irqtype = mp_ExtINT;
        intsrc.srcbusirq = 0;
        intsrc.dstirq = 0;      /* 8259A to INTIN0 */
        mp_save_irq(&intsrc);
}


static void __init construct_ioapic_table(int mpc_default_type)
{
        struct mpc_ioapic ioapic;
        struct mpc_bus bus;

        bus.type = MP_BUS;
        bus.busid = 0;
        switch (mpc_default_type) {
        default:
                pr_err("???\nUnknown standard configuration %d\n",
                       mpc_default_type);
                fallthrough;
        case 1:
        case 5:
                memcpy(bus.bustype, "ISA   ", 6);
                break;
        case 2:
        case 6:
        case 3:
                memcpy(bus.bustype, "EISA  ", 6);
                break;
        }
        MP_bus_info(&bus);
        if (mpc_default_type > 4) {
                bus.busid = 1;
                memcpy(bus.bustype, "PCI   ", 6);
                MP_bus_info(&bus);
        }

        ioapic.type     = MP_IOAPIC;
        ioapic.apicid   = 2;
        ioapic.apicver  = mpc_default_type > 4 ? 0x10 : 0x01;
        ioapic.flags    = MPC_APIC_USABLE;
        ioapic.apicaddr = IO_APIC_DEFAULT_PHYS_BASE;
        MP_ioapic_info(&ioapic);

        /*
         * We set up most of the low 16 IO-APIC pins according to MPS rules.
         */
        construct_default_ioirq_mptable(mpc_default_type);
}
#else
static inline void __init construct_ioapic_table(int mpc_default_type) { }
#endif

static inline void __init construct_default_ISA_mptable(int mpc_default_type)
{
        struct mpc_cpu processor;
        struct mpc_lintsrc lintsrc;
        int linttypes[2] = { mp_ExtINT, mp_NMI };
        int i;

        /*
         * 2 CPUs, numbered 0 & 1.
         */
        processor.type = MP_PROCESSOR;
        /* Either an integrated APIC or a discrete 82489DX. */
        processor.apicver = mpc_default_type > 4 ? 0x10 : 0x01;
        processor.cpuflag = CPU_ENABLED;
        processor.cpufeature = (boot_cpu_data.x86 << 8) |
            (boot_cpu_data.x86_model << 4) | boot_cpu_data.x86_stepping;
        processor.featureflag = boot_cpu_data.x86_capability[CPUID_1_EDX];
        processor.reserved[0] = 0;
        processor.reserved[1] = 0;
        for (i = 0; i < 2; i++) {
                processor.apicid = i;
                MP_processor_info(&processor);
        }

        construct_ioapic_table(mpc_default_type);

        lintsrc.type = MP_LINTSRC;
        lintsrc.irqflag = MP_IRQTRIG_DEFAULT | MP_IRQPOL_DEFAULT;
        lintsrc.srcbusid = 0;
        lintsrc.srcbusirq = 0;
        lintsrc.destapic = MP_APIC_ALL;
        for (i = 0; i < 2; i++) {
                lintsrc.irqtype = linttypes[i];
                lintsrc.destapiclint = i;
                MP_lintsrc_info(&lintsrc);
        }
}

static unsigned long mpf_base;
static bool mpf_found;

static unsigned long __init get_mpc_size(unsigned long physptr)
{
        struct mpc_table *mpc;
        unsigned long size;

        mpc = early_memremap(physptr, PAGE_SIZE);
        size = mpc->length;
        early_memunmap(mpc, PAGE_SIZE);
        apic_pr_verbose("  mpc: %lx-%lx\n", physptr, physptr + size);

        return size;
}

static int __init check_physptr(struct mpf_intel *mpf, unsigned int early)
{
        struct mpc_table *mpc;
        unsigned long size;

        size = get_mpc_size(mpf->physptr);
        mpc = early_memremap(mpf->physptr, size);

        /*
         * Read the physical hardware table.  Anything here will
         * override the defaults.
         */
        if (!smp_read_mpc(mpc, early)) {
#ifdef CONFIG_X86_LOCAL_APIC
                smp_found_config = 0;
#endif
                pr_err("BIOS bug, MP table errors detected!...\n");
                pr_cont("... disabling SMP support. (tell your hw vendor)\n");
                early_memunmap(mpc, size);
                return -1;
        }
        early_memunmap(mpc, size);

        if (early)
                return -1;

#ifdef CONFIG_X86_IO_APIC
        /*
         * If there are no explicit MP IRQ entries, then we are
         * broken.  We set up most of the low 16 IO-APIC pins to
         * ISA defaults and hope it will work.
         */
        if (!mp_irq_entries) {
                struct mpc_bus bus;

                pr_err("BIOS bug, no explicit IRQ entries, using default mptable. (tell your hw vendor)\n");

                bus.type = MP_BUS;
                bus.busid = 0;
                memcpy(bus.bustype, "ISA   ", 6);
                MP_bus_info(&bus);

                construct_default_ioirq_mptable(0);
        }
#endif

        return 0;
}

/*
 * Scan the memory blocks for an SMP configuration block.
 */
static __init void mpparse_get_smp_config(unsigned int early)
{
        struct mpf_intel *mpf;

        if (!smp_found_config)
                return;

        if (!mpf_found)
                return;

        if (acpi_lapic && early)
                return;

        /*
         * MPS doesn't support hyperthreading, aka only have
         * thread 0 apic id in MPS table
         */
        if (acpi_lapic && acpi_ioapic)
                return;

        mpf = early_memremap(mpf_base, sizeof(*mpf));
        if (!mpf) {
                pr_err("MPTABLE: error mapping MP table\n");
                return;
        }

        pr_info("Intel MultiProcessor Specification v1.%d\n",
                mpf->specification);
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_32)
        if (mpf->feature2 & (1 << 7)) {
                pr_info("    IMCR and PIC compatibility mode.\n");
                pic_mode = 1;
        } else {
                pr_info("    Virtual Wire compatibility mode.\n");
                pic_mode = 0;
        }
#endif
        /*
         * Now see if we need to read further.
         */
        if (mpf->feature1) {
                if (early) {
                        /* Local APIC has default address */
                        register_lapic_address(APIC_DEFAULT_PHYS_BASE);
                        goto out;
                }

                pr_info("Default MP configuration #%d\n", mpf->feature1);
                construct_default_ISA_mptable(mpf->feature1);

        } else if (mpf->physptr) {
                if (check_physptr(mpf, early))
                        goto out;
        } else
                BUG();

        if (!early && !acpi_lapic)
                pr_info("Processors: %d\n", num_procs);
        /*
         * Only use the first configuration found.
         */
out:
        early_memunmap(mpf, sizeof(*mpf));
}

void __init mpparse_parse_early_smp_config(void)
{
        mpparse_get_smp_config(true);
}

void __init mpparse_parse_smp_config(void)
{
        mpparse_get_smp_config(false);
}

static void __init smp_reserve_memory(struct mpf_intel *mpf)
{
        memblock_reserve(mpf->physptr, get_mpc_size(mpf->physptr));
}

static int __init smp_scan_config(unsigned long base, unsigned long length)
{
        unsigned int *bp;
        struct mpf_intel *mpf;
        int ret = 0;

        apic_pr_verbose("Scan for SMP in [mem %#010lx-%#010lx]\n", base, base + length - 1);
        BUILD_BUG_ON(sizeof(*mpf) != 16);

        while (length > 0) {
                bp = early_memremap(base, length);
                mpf = (struct mpf_intel *)bp;
                if ((*bp == SMP_MAGIC_IDENT) &&
                    (mpf->length == 1) &&
                    !mpf_checksum((unsigned char *)bp, 16) &&
                    ((mpf->specification == 1)
                     || (mpf->specification == 4))) {
#ifdef CONFIG_X86_LOCAL_APIC
                        smp_found_config = 1;
#endif
                        mpf_base = base;
                        mpf_found = true;

                        pr_info("found SMP MP-table at [mem %#010lx-%#010lx]\n",
                                base, base + sizeof(*mpf) - 1);

                        memblock_reserve(base, sizeof(*mpf));
                        if (mpf->physptr)
                                smp_reserve_memory(mpf);

                        ret = 1;
                }
                early_memunmap(bp, length);

                if (ret)
                        break;

                base += 16;
                length -= 16;
        }
        return ret;
}

void __init mpparse_find_mptable(void)
{
        unsigned int address;

        /*
         * FIXME: Linux assumes you have 640K of base ram..
         * this continues the error...
         *
         * 1) Scan the bottom 1K for a signature
         * 2) Scan the top 1K of base RAM
         * 3) Scan the 64K of bios
         */
        if (smp_scan_config(0x0, 0x400) ||
            smp_scan_config(639 * 0x400, 0x400) ||
            smp_scan_config(0xF0000, 0x10000))
                return;
        /*
         * If it is an SMP machine we should know now, unless the
         * configuration is in an EISA bus machine with an
         * extended bios data area.
         *
         * there is a real-mode segmented pointer pointing to the
         * 4K EBDA area at 0x40E, calculate and scan it here.
         *
         * NOTE! There are Linux loaders that will corrupt the EBDA
         * area, and as such this kind of SMP config may be less
         * trustworthy, simply because the SMP table may have been
         * stomped on during early boot. These loaders are buggy and
         * should be fixed.
         *
         * MP1.4 SPEC states to only scan first 1K of 4K EBDA.
         */

        address = get_bios_ebda();
        if (address)
                smp_scan_config(address, 0x400);
}

#ifdef CONFIG_X86_IO_APIC
static u8 __initdata irq_used[MAX_IRQ_SOURCES];

static int  __init get_MP_intsrc_index(struct mpc_intsrc *m)
{
        int i;

        if (m->irqtype != mp_INT)
                return 0;

        if (m->irqflag != (MP_IRQTRIG_LEVEL | MP_IRQPOL_ACTIVE_LOW))
                return 0;

        /* not legacy */

        for (i = 0; i < mp_irq_entries; i++) {
                if (mp_irqs[i].irqtype != mp_INT)
                        continue;

                if (mp_irqs[i].irqflag != (MP_IRQTRIG_LEVEL |
                                           MP_IRQPOL_ACTIVE_LOW))
                        continue;

                if (mp_irqs[i].srcbus != m->srcbus)
                        continue;
                if (mp_irqs[i].srcbusirq != m->srcbusirq)
                        continue;
                if (irq_used[i]) {
                        /* already claimed */
                        return -2;
                }
                irq_used[i] = 1;
                return i;
        }

        /* not found */
        return -1;
}

#define SPARE_SLOT_NUM 20

static struct mpc_intsrc __initdata *m_spare[SPARE_SLOT_NUM];

static void __init check_irq_src(struct mpc_intsrc *m, int *nr_m_spare)
{
        int i;

        apic_pr_verbose("OLD ");
        print_mp_irq_info(m);

        i = get_MP_intsrc_index(m);
        if (i > 0) {
                memcpy(m, &mp_irqs[i], sizeof(*m));
                apic_pr_verbose("NEW ");
                print_mp_irq_info(&mp_irqs[i]);
                return;
        }
        if (!i) {
                /* legacy, do nothing */
                return;
        }
        if (*nr_m_spare < SPARE_SLOT_NUM) {
                /*
                 * not found (-1), or duplicated (-2) are invalid entries,
                 * we need to use the slot later
                 */
                m_spare[*nr_m_spare] = m;
                *nr_m_spare += 1;
        }
}

static int __init
check_slot(unsigned long mpc_new_phys, unsigned long mpc_new_length, int count)
{
        if (!mpc_new_phys || count <= mpc_new_length) {
                WARN(1, "update_mptable: No spare slots (length: %x)\n", count);
                return -1;
        }

        return 0;
}
#else /* CONFIG_X86_IO_APIC */
static
inline void __init check_irq_src(struct mpc_intsrc *m, int *nr_m_spare) {}
#endif /* CONFIG_X86_IO_APIC */

static int  __init replace_intsrc_all(struct mpc_table *mpc,
                                        unsigned long mpc_new_phys,
                                        unsigned long mpc_new_length)
{
#ifdef CONFIG_X86_IO_APIC
        int i;
#endif
        int count = sizeof(*mpc);
        int nr_m_spare = 0;
        unsigned char *mpt = ((unsigned char *)mpc) + count;

        pr_info("mpc_length %x\n", mpc->length);
        while (count < mpc->length) {
                switch (*mpt) {
                case MP_PROCESSOR:
                        skip_entry(&mpt, &count, sizeof(struct mpc_cpu));
                        break;
                case MP_BUS:
                        skip_entry(&mpt, &count, sizeof(struct mpc_bus));
                        break;
                case MP_IOAPIC:
                        skip_entry(&mpt, &count, sizeof(struct mpc_ioapic));
                        break;
                case MP_INTSRC:
                        check_irq_src((struct mpc_intsrc *)mpt, &nr_m_spare);
                        skip_entry(&mpt, &count, sizeof(struct mpc_intsrc));
                        break;
                case MP_LINTSRC:
                        skip_entry(&mpt, &count, sizeof(struct mpc_lintsrc));
                        break;
                default:
                        /* wrong mptable */
                        smp_dump_mptable(mpc, mpt);
                        goto out;
                }
        }

#ifdef CONFIG_X86_IO_APIC
        for (i = 0; i < mp_irq_entries; i++) {
                if (irq_used[i])
                        continue;

                if (mp_irqs[i].irqtype != mp_INT)
                        continue;

                if (mp_irqs[i].irqflag != (MP_IRQTRIG_LEVEL |
                                           MP_IRQPOL_ACTIVE_LOW))
                        continue;

                if (nr_m_spare > 0) {
                        apic_pr_verbose("*NEW* found\n");
                        nr_m_spare--;
                        memcpy(m_spare[nr_m_spare], &mp_irqs[i], sizeof(mp_irqs[i]));
                        m_spare[nr_m_spare] = NULL;
                } else {
                        struct mpc_intsrc *m = (struct mpc_intsrc *)mpt;
                        count += sizeof(struct mpc_intsrc);
                        if (check_slot(mpc_new_phys, mpc_new_length, count) < 0)
                                goto out;
                        memcpy(m, &mp_irqs[i], sizeof(*m));
                        mpc->length = count;
                        mpt += sizeof(struct mpc_intsrc);
                }
                print_mp_irq_info(&mp_irqs[i]);
        }
#endif
out:
        /* update checksum */
        mpc->checksum = 0;
        mpc->checksum -= mpf_checksum((unsigned char *)mpc, mpc->length);

        return 0;
}

int enable_update_mptable;

static int __init update_mptable_setup(char *str)
{
        enable_update_mptable = 1;
#ifdef CONFIG_PCI
        pci_routeirq = 1;
#endif
        return 0;
}
early_param("update_mptable", update_mptable_setup);

static unsigned long __initdata mpc_new_phys;
static unsigned long mpc_new_length __initdata = 4096;

/* alloc_mptable or alloc_mptable=4k */
static int __initdata alloc_mptable;
static int __init parse_alloc_mptable_opt(char *p)
{
        enable_update_mptable = 1;
#ifdef CONFIG_PCI
        pci_routeirq = 1;
#endif
        alloc_mptable = 1;
        if (!p)
                return 0;
        mpc_new_length = memparse(p, &p);
        return 0;
}
early_param("alloc_mptable", parse_alloc_mptable_opt);

void __init e820__memblock_alloc_reserved_mpc_new(void)
{
        if (enable_update_mptable && alloc_mptable)
                mpc_new_phys = e820__memblock_alloc_reserved(mpc_new_length, 4);
}

static int __init update_mp_table(void)
{
        char str[16];
        char oem[10];
        struct mpf_intel *mpf;
        struct mpc_table *mpc, *mpc_new;
        unsigned long size;

        if (!enable_update_mptable)
                return 0;

        if (!mpf_found)
                return 0;

        mpf = early_memremap(mpf_base, sizeof(*mpf));
        if (!mpf) {
                pr_err("MPTABLE: mpf early_memremap() failed\n");
                return 0;
        }

        /*
         * Now see if we need to go further.
         */
        if (mpf->feature1)
                goto do_unmap_mpf;

        if (!mpf->physptr)
                goto do_unmap_mpf;

        size = get_mpc_size(mpf->physptr);
        mpc = early_memremap(mpf->physptr, size);
        if (!mpc) {
                pr_err("MPTABLE: mpc early_memremap() failed\n");
                goto do_unmap_mpf;
        }

        if (!smp_check_mpc(mpc, oem, str))
                goto do_unmap_mpc;

        pr_info("mpf: %llx\n", (u64)mpf_base);
        pr_info("physptr: %x\n", mpf->physptr);

        if (mpc_new_phys && mpc->length > mpc_new_length) {
                mpc_new_phys = 0;
                pr_info("mpc_new_length is %ld, please use alloc_mptable=8k\n",
                        mpc_new_length);
        }

        if (!mpc_new_phys) {
                unsigned char old, new;
                /* check if we can change the position */
                mpc->checksum = 0;
                old = mpf_checksum((unsigned char *)mpc, mpc->length);
                mpc->checksum = 0xff;
                new = mpf_checksum((unsigned char *)mpc, mpc->length);
                if (old == new) {
                        pr_info("mpc is readonly, please try alloc_mptable instead\n");
                        goto do_unmap_mpc;
                }
                pr_info("use in-position replacing\n");
        } else {
                mpc_new = early_memremap(mpc_new_phys, mpc_new_length);
                if (!mpc_new) {
                        pr_err("MPTABLE: new mpc early_memremap() failed\n");
                        goto do_unmap_mpc;
                }
                mpf->physptr = mpc_new_phys;
                memcpy(mpc_new, mpc, mpc->length);
                early_memunmap(mpc, size);
                mpc = mpc_new;
                size = mpc_new_length;
                /* check if we can modify that */
                if (mpc_new_phys - mpf->physptr) {
                        struct mpf_intel *mpf_new;
                        /* steal 16 bytes from [0, 1k) */
                        mpf_new = early_memremap(0x400 - 16, sizeof(*mpf_new));
                        if (!mpf_new) {
                                pr_err("MPTABLE: new mpf early_memremap() failed\n");
                                goto do_unmap_mpc;
                        }
                        pr_info("mpf new: %x\n", 0x400 - 16);
                        memcpy(mpf_new, mpf, 16);
                        early_memunmap(mpf, sizeof(*mpf));
                        mpf = mpf_new;
                        mpf->physptr = mpc_new_phys;
                }
                mpf->checksum = 0;
                mpf->checksum -= mpf_checksum((unsigned char *)mpf, 16);
                pr_info("physptr new: %x\n", mpf->physptr);
        }

        /*
         * only replace the one with mp_INT and
         *       MP_IRQ_TRIGGER_LEVEL|MP_IRQ_POLARITY_LOW,
         * already in mp_irqs , stored by ... and mp_config_acpi_gsi,
         * may need pci=routeirq for all coverage
         */
        replace_intsrc_all(mpc, mpc_new_phys, mpc_new_length);

do_unmap_mpc:
        early_memunmap(mpc, size);

do_unmap_mpf:
        early_memunmap(mpf, sizeof(*mpf));

        return 0;
}

late_initcall(update_mp_table);