// SPDX-License-Identifier: GPL-2.0

#include <linux/cpumask.h>
#include <linux/acpi.h>

#include "local.h"

int x2apic_phys;

static struct apic apic_x2apic_phys;
u32 x2apic_max_apicid __ro_after_init = UINT_MAX;

void __init x2apic_set_max_apicid(u32 apicid)
{
        x2apic_max_apicid = apicid;
        if (apic->x2apic_set_max_apicid)
                apic->max_apic_id = apicid;
}

static int __init set_x2apic_phys_mode(char *arg)
{
        x2apic_phys = 1;
        return 0;
}
early_param("x2apic_phys", set_x2apic_phys_mode);

static bool x2apic_fadt_phys(void)
{
#ifdef CONFIG_ACPI
        if ((acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID) &&
                (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL)) {
                printk(KERN_DEBUG "System requires x2apic physical mode\n");
                return true;
        }
#endif
        return false;
}

static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
{
        return x2apic_enabled() && (x2apic_phys || x2apic_fadt_phys());
}

static void x2apic_send_IPI(int cpu, int vector)
{
        u32 dest = per_cpu(x86_cpu_to_apicid, cpu);

        /* x2apic MSRs are special and need a special fence: */
        weak_wrmsr_fence();
        __x2apic_send_IPI_dest(dest, vector, APIC_DEST_PHYSICAL);
}

static void
__x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest)
{
        unsigned long query_cpu;
        unsigned long this_cpu;
        unsigned long flags;

        /* x2apic MSRs are special and need a special fence: */
        weak_wrmsr_fence();

        local_irq_save(flags);

        this_cpu = smp_processor_id();
        for_each_cpu(query_cpu, mask) {
                if (apic_dest == APIC_DEST_ALLBUT && this_cpu == query_cpu)
                        continue;
                __x2apic_send_IPI_dest(per_cpu(x86_cpu_to_apicid, query_cpu),
                                       vector, APIC_DEST_PHYSICAL);
        }
        local_irq_restore(flags);
}

static void x2apic_send_IPI_mask(const struct cpumask *mask, int vector)
{
        __x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLINC);
}

static void
 x2apic_send_IPI_mask_allbutself(const struct cpumask *mask, int vector)
{
        __x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLBUT);
}

static void __x2apic_send_IPI_shorthand(int vector, u32 which)
{
        unsigned long cfg = __prepare_ICR(which, vector, 0);

        /* x2apic MSRs are special and need a special fence: */
        weak_wrmsr_fence();
        native_x2apic_icr_write(cfg, 0);
}

void x2apic_send_IPI_allbutself(int vector)
{
        __x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLBUT);
}

void x2apic_send_IPI_all(int vector)
{
        __x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLINC);
}

void x2apic_send_IPI_self(int vector)
{
        apic_write(APIC_SELF_IPI, vector);
}

static int x2apic_phys_probe(void)
{
        if (!x2apic_mode)
                return 0;

        if (x2apic_phys || x2apic_fadt_phys())
                return 1;

        return apic == &apic_x2apic_phys;
}

u32 x2apic_get_apic_id(u32 id)
{
        return id;
}

static struct apic apic_x2apic_phys __ro_after_init = {

        .name                           = "physical x2apic",
        .probe                          = x2apic_phys_probe,
        .acpi_madt_oem_check            = x2apic_acpi_madt_oem_check,

        .dest_mode_logical              = false,

        .disable_esr                    = 0,

        .cpu_present_to_apicid          = default_cpu_present_to_apicid,

        .max_apic_id                    = UINT_MAX,
        .x2apic_set_max_apicid          = true,
        .get_apic_id                    = x2apic_get_apic_id,

        .calc_dest_apicid               = apic_default_calc_apicid,

        .send_IPI                       = x2apic_send_IPI,
        .send_IPI_mask                  = x2apic_send_IPI_mask,
        .send_IPI_mask_allbutself       = x2apic_send_IPI_mask_allbutself,
        .send_IPI_allbutself            = x2apic_send_IPI_allbutself,
        .send_IPI_all                   = x2apic_send_IPI_all,
        .send_IPI_self                  = x2apic_send_IPI_self,
        .nmi_to_offline_cpu             = true,

        .read                           = native_apic_msr_read,
        .write                          = native_apic_msr_write,
        .eoi                            = native_apic_msr_eoi,
        .icr_read                       = native_x2apic_icr_read,
        .icr_write                      = native_x2apic_icr_write,
};

apic_driver(apic_x2apic_phys);