arch/x86/kernel/apic/vector.c

root/arch/x86/kernel/apic/vector.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Local APIC related interfaces to support IOAPIC, MSI, etc.
 *
 * Copyright (C) 1997, 1998, 1999, 2000, 2009 Ingo Molnar, Hajnalka Szabo
 *      Moved from arch/x86/kernel/apic/io_apic.c.
 * Jiang Liu <jiang.liu@linux.intel.com>
 *      Enable support of hierarchical irqdomains
 */
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/slab.h>
#include <asm/irqdomain.h>
#include <asm/hw_irq.h>
#include <asm/traps.h>
#include <asm/apic.h>
#include <asm/i8259.h>
#include <asm/desc.h>
#include <asm/irq_remapping.h>

#include <asm/trace/irq_vectors.h>

struct apic_chip_data {
        struct irq_cfg          hw_irq_cfg;
        unsigned int            vector;
        unsigned int            prev_vector;
        unsigned int            cpu;
        unsigned int            prev_cpu;
        unsigned int            irq;
        struct hlist_node       clist;
        unsigned int            move_in_progress        : 1,
                                is_managed              : 1,
                                can_reserve             : 1,
                                has_reserved            : 1;
};

struct irq_domain *x86_vector_domain;
EXPORT_SYMBOL_GPL(x86_vector_domain);
static DEFINE_RAW_SPINLOCK(vector_lock);
static cpumask_var_t vector_searchmask;
static struct irq_chip lapic_controller;
static struct irq_matrix *vector_matrix;
#ifdef CONFIG_SMP

static void vector_cleanup_callback(struct timer_list *tmr);

struct vector_cleanup {
        struct hlist_head       head;
        struct timer_list       timer;
};

static DEFINE_PER_CPU(struct vector_cleanup, vector_cleanup) = {
        .head   = HLIST_HEAD_INIT,
        .timer  = __TIMER_INITIALIZER(vector_cleanup_callback, TIMER_PINNED),
};
#endif

void lock_vector_lock(void)
{
        /* Used to the online set of cpus does not change
         * during assign_irq_vector.
         */
        raw_spin_lock(&vector_lock);
}

void unlock_vector_lock(void)
{
        raw_spin_unlock(&vector_lock);
}

void init_irq_alloc_info(struct irq_alloc_info *info,
                         const struct cpumask *mask)
{
        memset(info, 0, sizeof(*info));
        info->mask = mask;
}

void copy_irq_alloc_info(struct irq_alloc_info *dst, struct irq_alloc_info *src)
{
        if (src)
                *dst = *src;
        else
                memset(dst, 0, sizeof(*dst));
}

static struct apic_chip_data *apic_chip_data(struct irq_data *irqd)
{
        if (!irqd)
                return NULL;

        while (irqd->parent_data)
                irqd = irqd->parent_data;

        return irqd->chip_data;
}

struct irq_cfg *irqd_cfg(struct irq_data *irqd)
{
        struct apic_chip_data *apicd = apic_chip_data(irqd);

        return apicd ? &apicd->hw_irq_cfg : NULL;
}
EXPORT_SYMBOL_GPL(irqd_cfg);

struct irq_cfg *irq_cfg(unsigned int irq)
{
        return irqd_cfg(irq_get_irq_data(irq));
}

static struct apic_chip_data *alloc_apic_chip_data(int node)
{
        struct apic_chip_data *apicd;

        apicd = kzalloc_node(sizeof(*apicd), GFP_KERNEL, node);
        if (apicd)
                INIT_HLIST_NODE(&apicd->clist);
        return apicd;
}

static void free_apic_chip_data(struct apic_chip_data *apicd)
{
        kfree(apicd);
}

static void apic_update_irq_cfg(struct irq_data *irqd, unsigned int vector,
                                unsigned int cpu)
{
        struct apic_chip_data *apicd = apic_chip_data(irqd);

        lockdep_assert_held(&vector_lock);

        apicd->hw_irq_cfg.vector = vector;
        apicd->hw_irq_cfg.dest_apicid = apic->calc_dest_apicid(cpu);

        apic_update_vector(cpu, vector, true);

        irq_data_update_effective_affinity(irqd, cpumask_of(cpu));
        trace_vector_config(irqd->irq, vector, cpu, apicd->hw_irq_cfg.dest_apicid);
}

static void apic_free_vector(unsigned int cpu, unsigned int vector, bool managed)
{
        apic_update_vector(cpu, vector, false);
        irq_matrix_free(vector_matrix, cpu, vector, managed);
}

static void chip_data_update(struct irq_data *irqd, unsigned int newvec, unsigned int newcpu)
{
        struct apic_chip_data *apicd = apic_chip_data(irqd);
        struct irq_desc *desc = irq_data_to_desc(irqd);
        bool managed = irqd_affinity_is_managed(irqd);

        lockdep_assert_held(&vector_lock);

        trace_vector_update(irqd->irq, newvec, newcpu, apicd->vector,
                            apicd->cpu);

        /*
         * If there is no vector associated or if the associated vector is
         * the shutdown vector, which is associated to make PCI/MSI
         * shutdown mode work, then there is nothing to release. Clear out
         * prev_vector for this and the offlined target case.
         */
        apicd->prev_vector = 0;
        if (!apicd->vector || apicd->vector == MANAGED_IRQ_SHUTDOWN_VECTOR)
                goto setnew;
        /*
         * If the target CPU of the previous vector is online, then mark
         * the vector as move in progress and store it for cleanup when the
         * first interrupt on the new vector arrives. If the target CPU is
         * offline then the regular release mechanism via the cleanup
         * vector is not possible and the vector can be immediately freed
         * in the underlying matrix allocator.
         */
        if (cpu_online(apicd->cpu)) {
                apicd->move_in_progress = true;
                apicd->prev_vector = apicd->vector;
                apicd->prev_cpu = apicd->cpu;
                WARN_ON_ONCE(apicd->cpu == newcpu);
        } else {
                apic_free_vector(apicd->cpu, apicd->vector, managed);
        }

setnew:
        apicd->vector = newvec;
        apicd->cpu = newcpu;
        BUG_ON(!IS_ERR_OR_NULL(per_cpu(vector_irq, newcpu)[newvec]));
        per_cpu(vector_irq, newcpu)[newvec] = desc;
        apic_update_irq_cfg(irqd, newvec, newcpu);
}

static void vector_assign_managed_shutdown(struct irq_data *irqd)
{
        unsigned int cpu = cpumask_first(cpu_online_mask);

        apic_update_irq_cfg(irqd, MANAGED_IRQ_SHUTDOWN_VECTOR, cpu);
}

static int reserve_managed_vector(struct irq_data *irqd)
{
        const struct cpumask *affmsk = irq_data_get_affinity_mask(irqd);
        struct apic_chip_data *apicd = apic_chip_data(irqd);
        unsigned long flags;
        int ret;

        raw_spin_lock_irqsave(&vector_lock, flags);
        apicd->is_managed = true;
        ret = irq_matrix_reserve_managed(vector_matrix, affmsk);
        raw_spin_unlock_irqrestore(&vector_lock, flags);
        trace_vector_reserve_managed(irqd->irq, ret);
        return ret;
}

static void reserve_irq_vector_locked(struct irq_data *irqd)
{
        struct apic_chip_data *apicd = apic_chip_data(irqd);

        irq_matrix_reserve(vector_matrix);
        apicd->can_reserve = true;
        apicd->has_reserved = true;
        irqd_set_can_reserve(irqd);
        trace_vector_reserve(irqd->irq, 0);
        vector_assign_managed_shutdown(irqd);
}

static int reserve_irq_vector(struct irq_data *irqd)
{
        unsigned long flags;

        raw_spin_lock_irqsave(&vector_lock, flags);
        reserve_irq_vector_locked(irqd);
        raw_spin_unlock_irqrestore(&vector_lock, flags);
        return 0;
}

static int
assign_vector_locked(struct irq_data *irqd, const struct cpumask *dest)
{
        struct apic_chip_data *apicd = apic_chip_data(irqd);
        bool resvd = apicd->has_reserved;
        unsigned int cpu = apicd->cpu;
        int vector = apicd->vector;

        lockdep_assert_held(&vector_lock);

        /*
         * If the current target CPU is online and in the new requested
         * affinity mask, there is no point in moving the interrupt from
         * one CPU to another.
         */
        if (vector && cpu_online(cpu) && cpumask_test_cpu(cpu, dest))
                return 0;

        /*
         * Careful here. @apicd might either have move_in_progress set or
         * be enqueued for cleanup. Assigning a new vector would either
         * leave a stale vector on some CPU around or in case of a pending
         * cleanup corrupt the hlist.
         */
        if (apicd->move_in_progress || !hlist_unhashed(&apicd->clist))
                return -EBUSY;

        vector = irq_matrix_alloc(vector_matrix, dest, resvd, &cpu);
        trace_vector_alloc(irqd->irq, vector, resvd, vector);
        if (vector < 0)
                return vector;
        chip_data_update(irqd, vector, cpu);

        return 0;
}

static int assign_irq_vector(struct irq_data *irqd, const struct cpumask *dest)
{
        unsigned long flags;
        int ret;

        raw_spin_lock_irqsave(&vector_lock, flags);
        cpumask_and(vector_searchmask, dest, cpu_online_mask);
        ret = assign_vector_locked(irqd, vector_searchmask);
        raw_spin_unlock_irqrestore(&vector_lock, flags);
        return ret;
}

static int assign_irq_vector_any_locked(struct irq_data *irqd)
{
        /* Get the affinity mask - either irq_default_affinity or (user) set */
        const struct cpumask *affmsk = irq_data_get_affinity_mask(irqd);
        int node = irq_data_get_node(irqd);

        if (node != NUMA_NO_NODE) {
                /* Try the intersection of @affmsk and node mask */
                cpumask_and(vector_searchmask, cpumask_of_node(node), affmsk);
                if (!assign_vector_locked(irqd, vector_searchmask))
                        return 0;
        }

        /* Try the full affinity mask */
        cpumask_and(vector_searchmask, affmsk, cpu_online_mask);
        if (!assign_vector_locked(irqd, vector_searchmask))
                return 0;

        if (node != NUMA_NO_NODE) {
                /* Try the node mask */
                if (!assign_vector_locked(irqd, cpumask_of_node(node)))
                        return 0;
        }

        /* Try the full online mask */
        return assign_vector_locked(irqd, cpu_online_mask);
}

static int
assign_irq_vector_policy(struct irq_data *irqd, struct irq_alloc_info *info)
{
        if (irqd_affinity_is_managed(irqd))
                return reserve_managed_vector(irqd);
        if (info->mask)
                return assign_irq_vector(irqd, info->mask);
        /*
         * Make only a global reservation with no guarantee. A real vector
         * is associated at activation time.
         */
        return reserve_irq_vector(irqd);
}

static int
assign_managed_vector(struct irq_data *irqd, const struct cpumask *dest)
{
        const struct cpumask *affmsk = irq_data_get_affinity_mask(irqd);
        struct apic_chip_data *apicd = apic_chip_data(irqd);
        int vector, cpu;

        cpumask_and(vector_searchmask, dest, affmsk);

        /* set_affinity might call here for nothing */
        if (apicd->vector && cpumask_test_cpu(apicd->cpu, vector_searchmask))
                return 0;
        vector = irq_matrix_alloc_managed(vector_matrix, vector_searchmask,
                                          &cpu);
        trace_vector_alloc_managed(irqd->irq, vector, vector);
        if (vector < 0)
                return vector;
        chip_data_update(irqd, vector, cpu);

        return 0;
}

static void clear_irq_vector(struct irq_data *irqd)
{
        struct apic_chip_data *apicd = apic_chip_data(irqd);
        bool managed = irqd_affinity_is_managed(irqd);
        unsigned int vector = apicd->vector;

        lockdep_assert_held(&vector_lock);

        if (!vector)
                return;

        trace_vector_clear(irqd->irq, vector, apicd->cpu, apicd->prev_vector,
                           apicd->prev_cpu);

        per_cpu(vector_irq, apicd->cpu)[vector] = VECTOR_SHUTDOWN;
        apic_free_vector(apicd->cpu, vector, managed);
        apicd->vector = 0;

        /* Clean up move in progress */
        vector = apicd->prev_vector;
        if (!vector)
                return;

        per_cpu(vector_irq, apicd->prev_cpu)[vector] = VECTOR_SHUTDOWN;
        apic_free_vector(apicd->prev_cpu, vector, managed);
        apicd->prev_vector = 0;
        apicd->move_in_progress = 0;
        hlist_del_init(&apicd->clist);
}

static void x86_vector_deactivate(struct irq_domain *dom, struct irq_data *irqd)
{
        struct apic_chip_data *apicd = apic_chip_data(irqd);
        unsigned long flags;

        trace_vector_deactivate(irqd->irq, apicd->is_managed,
                                apicd->can_reserve, false);

        /* Regular fixed assigned interrupt */
        if (!apicd->is_managed && !apicd->can_reserve)
                return;
        /* If the interrupt has a global reservation, nothing to do */
        if (apicd->has_reserved)
                return;

        raw_spin_lock_irqsave(&vector_lock, flags);
        clear_irq_vector(irqd);
        if (apicd->can_reserve)
                reserve_irq_vector_locked(irqd);
        else
                vector_assign_managed_shutdown(irqd);
        raw_spin_unlock_irqrestore(&vector_lock, flags);
}

static int activate_reserved(struct irq_data *irqd)
{
        struct apic_chip_data *apicd = apic_chip_data(irqd);
        int ret;

        ret = assign_irq_vector_any_locked(irqd);
        if (!ret) {
                apicd->has_reserved = false;
                /*
                 * Core might have disabled reservation mode after
                 * allocating the irq descriptor. Ideally this should
                 * happen before allocation time, but that would require
                 * completely convoluted ways of transporting that
                 * information.
                 */
                if (!irqd_can_reserve(irqd))
                        apicd->can_reserve = false;
        }

        /*
         * Check to ensure that the effective affinity mask is a subset
         * the user supplied affinity mask, and warn the user if it is not
         */
        if (!cpumask_subset(irq_data_get_effective_affinity_mask(irqd),
                            irq_data_get_affinity_mask(irqd))) {
                pr_warn("irq %u: Affinity broken due to vector space exhaustion.\n",
                        irqd->irq);
        }

        return ret;
}

static int activate_managed(struct irq_data *irqd)
{
        const struct cpumask *dest = irq_data_get_affinity_mask(irqd);
        int ret;

        cpumask_and(vector_searchmask, dest, cpu_online_mask);
        if (WARN_ON_ONCE(cpumask_empty(vector_searchmask))) {
                /* Something in the core code broke! Survive gracefully */
                pr_err("Managed startup for irq %u, but no CPU\n", irqd->irq);
                return -EINVAL;
        }

        ret = assign_managed_vector(irqd, vector_searchmask);
        /*
         * This should not happen. The vector reservation got buggered.  Handle
         * it gracefully.
         */
        if (WARN_ON_ONCE(ret < 0)) {
                pr_err("Managed startup irq %u, no vector available\n",
                       irqd->irq);
        }
        return ret;
}

static int x86_vector_activate(struct irq_domain *dom, struct irq_data *irqd,
                               bool reserve)
{
        struct apic_chip_data *apicd = apic_chip_data(irqd);
        unsigned long flags;
        int ret = 0;

        trace_vector_activate(irqd->irq, apicd->is_managed,
                              apicd->can_reserve, reserve);

        raw_spin_lock_irqsave(&vector_lock, flags);
        if (!apicd->can_reserve && !apicd->is_managed)
                assign_irq_vector_any_locked(irqd);
        else if (reserve || irqd_is_managed_and_shutdown(irqd))
                vector_assign_managed_shutdown(irqd);
        else if (apicd->is_managed)
                ret = activate_managed(irqd);
        else if (apicd->has_reserved)
                ret = activate_reserved(irqd);
        raw_spin_unlock_irqrestore(&vector_lock, flags);
        return ret;
}

static void vector_free_reserved_and_managed(struct irq_data *irqd)
{
        const struct cpumask *dest = irq_data_get_affinity_mask(irqd);
        struct apic_chip_data *apicd = apic_chip_data(irqd);

        trace_vector_teardown(irqd->irq, apicd->is_managed,
                              apicd->has_reserved);

        if (apicd->has_reserved)
                irq_matrix_remove_reserved(vector_matrix);
        if (apicd->is_managed)
                irq_matrix_remove_managed(vector_matrix, dest);
}

static void x86_vector_free_irqs(struct irq_domain *domain,
                                 unsigned int virq, unsigned int nr_irqs)
{
        struct apic_chip_data *apicd;
        struct irq_data *irqd;
        unsigned long flags;
        int i;

        for (i = 0; i < nr_irqs; i++) {
                irqd = irq_domain_get_irq_data(x86_vector_domain, virq + i);
                if (irqd && irqd->chip_data) {
                        raw_spin_lock_irqsave(&vector_lock, flags);
                        clear_irq_vector(irqd);
                        vector_free_reserved_and_managed(irqd);
                        apicd = irqd->chip_data;
                        irq_domain_reset_irq_data(irqd);
                        raw_spin_unlock_irqrestore(&vector_lock, flags);
                        free_apic_chip_data(apicd);
                }
        }
}

static bool vector_configure_legacy(unsigned int virq, struct irq_data *irqd,
                                    struct apic_chip_data *apicd)
{
        unsigned long flags;
        bool realloc = false;

        apicd->vector = ISA_IRQ_VECTOR(virq);
        apicd->cpu = 0;

        raw_spin_lock_irqsave(&vector_lock, flags);
        /*
         * If the interrupt is activated, then it must stay at this vector
         * position. That's usually the timer interrupt (0).
         */
        if (irqd_is_activated(irqd)) {
                trace_vector_setup(virq, true, 0);
                apic_update_irq_cfg(irqd, apicd->vector, apicd->cpu);
        } else {
                /* Release the vector */
                apicd->can_reserve = true;
                irqd_set_can_reserve(irqd);
                clear_irq_vector(irqd);
                realloc = true;
        }
        raw_spin_unlock_irqrestore(&vector_lock, flags);
        return realloc;
}

static int x86_vector_alloc_irqs(struct irq_domain *domain, unsigned int virq,
                                 unsigned int nr_irqs, void *arg)
{
        struct irq_alloc_info *info = arg;
        struct apic_chip_data *apicd;
        struct irq_data *irqd;
        int i, err, node;

        if (apic_is_disabled)
                return -ENXIO;

        /*
         * Catch any attempt to touch the cascade interrupt on a PIC
         * equipped system.
         */
        if (WARN_ON_ONCE(info->flags & X86_IRQ_ALLOC_LEGACY &&
                         virq == PIC_CASCADE_IR))
                return -EINVAL;

        for (i = 0; i < nr_irqs; i++) {
                irqd = irq_domain_get_irq_data(domain, virq + i);
                BUG_ON(!irqd);
                node = irq_data_get_node(irqd);
                WARN_ON_ONCE(irqd->chip_data);
                apicd = alloc_apic_chip_data(node);
                if (!apicd) {
                        err = -ENOMEM;
                        goto error;
                }

                apicd->irq = virq + i;
                irqd->chip = &lapic_controller;
                irqd->chip_data = apicd;
                irqd->hwirq = virq + i;
                irqd_set_single_target(irqd);
                /*
                 * Prevent that any of these interrupts is invoked in
                 * non interrupt context via e.g. generic_handle_irq()
                 * as that can corrupt the affinity move state.
                 */
                irqd_set_handle_enforce_irqctx(irqd);

                /* Don't invoke affinity setter on deactivated interrupts */
                irqd_set_affinity_on_activate(irqd);

                /*
                 * Legacy vectors are already assigned when the IOAPIC
                 * takes them over. They stay on the same vector. This is
                 * required for check_timer() to work correctly as it might
                 * switch back to legacy mode. Only update the hardware
                 * config.
                 */
                if (info->flags & X86_IRQ_ALLOC_LEGACY) {
                        if (!vector_configure_legacy(virq + i, irqd, apicd))
                                continue;
                }

                err = assign_irq_vector_policy(irqd, info);
                trace_vector_setup(virq + i, false, err);
                if (err) {
                        irqd->chip_data = NULL;
                        free_apic_chip_data(apicd);
                        goto error;
                }
        }

        return 0;

error:
        x86_vector_free_irqs(domain, virq, i);
        return err;
}

#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
static void x86_vector_debug_show(struct seq_file *m, struct irq_domain *d,
                                  struct irq_data *irqd, int ind)
{
        struct apic_chip_data apicd;
        unsigned long flags;
        int irq;

        if (!irqd) {
                irq_matrix_debug_show(m, vector_matrix, ind);
                return;
        }

        irq = irqd->irq;
        if (irq < nr_legacy_irqs() && !test_bit(irq, &io_apic_irqs)) {
                seq_printf(m, "%*sVector: %5d\n", ind, "", ISA_IRQ_VECTOR(irq));
                seq_printf(m, "%*sTarget: Legacy PIC all CPUs\n", ind, "");
                return;
        }

        if (!irqd->chip_data) {
                seq_printf(m, "%*sVector: Not assigned\n", ind, "");
                return;
        }

        raw_spin_lock_irqsave(&vector_lock, flags);
        memcpy(&apicd, irqd->chip_data, sizeof(apicd));
        raw_spin_unlock_irqrestore(&vector_lock, flags);

        seq_printf(m, "%*sVector: %5u\n", ind, "", apicd.vector);
        seq_printf(m, "%*sTarget: %5u\n", ind, "", apicd.cpu);
        if (apicd.prev_vector) {
                seq_printf(m, "%*sPrevious vector: %5u\n", ind, "", apicd.prev_vector);
                seq_printf(m, "%*sPrevious target: %5u\n", ind, "", apicd.prev_cpu);
        }
        seq_printf(m, "%*smove_in_progress: %u\n", ind, "", apicd.move_in_progress ? 1 : 0);
        seq_printf(m, "%*sis_managed:       %u\n", ind, "", apicd.is_managed ? 1 : 0);
        seq_printf(m, "%*scan_reserve:      %u\n", ind, "", apicd.can_reserve ? 1 : 0);
        seq_printf(m, "%*shas_reserved:     %u\n", ind, "", apicd.has_reserved ? 1 : 0);
        seq_printf(m, "%*scleanup_pending:  %u\n", ind, "", !hlist_unhashed(&apicd.clist));
}
#endif

int x86_fwspec_is_ioapic(struct irq_fwspec *fwspec)
{
        if (fwspec->param_count != 1)
                return 0;

        if (is_fwnode_irqchip(fwspec->fwnode)) {
                const char *fwname = fwnode_get_name(fwspec->fwnode);
                return fwname && !strncmp(fwname, "IO-APIC-", 8) &&
                        simple_strtol(fwname+8, NULL, 10) == fwspec->param[0];
        }
        return to_of_node(fwspec->fwnode) &&
                of_device_is_compatible(to_of_node(fwspec->fwnode),
                                        "intel,ce4100-ioapic");
}

int x86_fwspec_is_hpet(struct irq_fwspec *fwspec)
{
        if (fwspec->param_count != 1)
                return 0;

        if (is_fwnode_irqchip(fwspec->fwnode)) {
                const char *fwname = fwnode_get_name(fwspec->fwnode);
                return fwname && !strncmp(fwname, "HPET-MSI-", 9) &&
                        simple_strtol(fwname+9, NULL, 10) == fwspec->param[0];
        }
        return 0;
}

static int x86_vector_select(struct irq_domain *d, struct irq_fwspec *fwspec,
                             enum irq_domain_bus_token bus_token)
{
        /*
         * HPET and I/OAPIC cannot be parented in the vector domain
         * if IRQ remapping is enabled. APIC IDs above 15 bits are
         * only permitted if IRQ remapping is enabled, so check that.
         */
        if (apic_id_valid(32768))
                return 0;

        return x86_fwspec_is_ioapic(fwspec) || x86_fwspec_is_hpet(fwspec);
}

static const struct irq_domain_ops x86_vector_domain_ops = {
        .select         = x86_vector_select,
        .alloc          = x86_vector_alloc_irqs,
        .free           = x86_vector_free_irqs,
        .activate       = x86_vector_activate,
        .deactivate     = x86_vector_deactivate,
#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
        .debug_show     = x86_vector_debug_show,
#endif
};

int __init arch_probe_nr_irqs(void)
{
        int nr;

        if (irq_get_nr_irqs() > NR_VECTORS * nr_cpu_ids)
                irq_set_nr_irqs(NR_VECTORS * nr_cpu_ids);

        nr = (gsi_top + nr_legacy_irqs()) + 8 * nr_cpu_ids;
#if defined(CONFIG_PCI_MSI)
        /*
         * for MSI and HT dyn irq
         */
        if (gsi_top <= NR_IRQS_LEGACY)
                nr +=  8 * nr_cpu_ids;
        else
                nr += gsi_top * 16;
#endif
        if (nr < irq_get_nr_irqs())
                irq_set_nr_irqs(nr);

        /*
         * We don't know if PIC is present at this point so we need to do
         * probe() to get the right number of legacy IRQs.
         */
        return legacy_pic->probe();
}

void lapic_assign_legacy_vector(unsigned int irq, bool replace)
{
        /*
         * Use assign system here so it won't get accounted as allocated
         * and movable in the cpu hotplug check and it prevents managed
         * irq reservation from touching it.
         */
        irq_matrix_assign_system(vector_matrix, ISA_IRQ_VECTOR(irq), replace);
}

void __init lapic_update_legacy_vectors(void)
{
        unsigned int i;

        if (IS_ENABLED(CONFIG_X86_IO_APIC) && nr_ioapics > 0)
                return;

        /*
         * If the IO/APIC is disabled via config, kernel command line or
         * lack of enumeration then all legacy interrupts are routed
         * through the PIC. Make sure that they are marked as legacy
         * vectors. PIC_CASCADE_IRQ has already been marked in
         * lapic_assign_system_vectors().
         */
        for (i = 0; i < nr_legacy_irqs(); i++) {
                if (i != PIC_CASCADE_IR)
                        lapic_assign_legacy_vector(i, true);
        }
}

void __init lapic_assign_system_vectors(void)
{
        unsigned int i, vector;

        for_each_set_bit(vector, system_vectors, NR_VECTORS)
                irq_matrix_assign_system(vector_matrix, vector, false);

        if (nr_legacy_irqs() > 1)
                lapic_assign_legacy_vector(PIC_CASCADE_IR, false);

        /* System vectors are reserved, online it */
        irq_matrix_online(vector_matrix);

        /* Mark the preallocated legacy interrupts */
        for (i = 0; i < nr_legacy_irqs(); i++) {
                /*
                 * Don't touch the cascade interrupt. It's unusable
                 * on PIC equipped machines. See the large comment
                 * in the IO/APIC code.
                 */
                if (i != PIC_CASCADE_IR)
                        irq_matrix_assign(vector_matrix, ISA_IRQ_VECTOR(i));
        }
}

int __init arch_early_irq_init(void)
{
        struct fwnode_handle *fn;

        fn = irq_domain_alloc_named_fwnode("VECTOR");
        BUG_ON(!fn);
        x86_vector_domain = irq_domain_create_tree(fn, &x86_vector_domain_ops,
                                                   NULL);
        BUG_ON(x86_vector_domain == NULL);
        irq_set_default_domain(x86_vector_domain);

        BUG_ON(!alloc_cpumask_var(&vector_searchmask, GFP_KERNEL));

        /*
         * Allocate the vector matrix allocator data structure and limit the
         * search area.
         */
        vector_matrix = irq_alloc_matrix(NR_VECTORS, FIRST_EXTERNAL_VECTOR,
                                         FIRST_SYSTEM_VECTOR);
        BUG_ON(!vector_matrix);

        return arch_early_ioapic_init();
}

#ifdef CONFIG_SMP

static struct irq_desc *__setup_vector_irq(int vector)
{
        int isairq = vector - ISA_IRQ_VECTOR(0);

        /* Check whether the irq is in the legacy space */
        if (isairq < 0 || isairq >= nr_legacy_irqs())
                return VECTOR_UNUSED;
        /* Check whether the irq is handled by the IOAPIC */
        if (test_bit(isairq, &io_apic_irqs))
                return VECTOR_UNUSED;
        return irq_to_desc(isairq);
}

/* Online the local APIC infrastructure and initialize the vectors */
void lapic_online(void)
{
        unsigned int vector;

        lockdep_assert_held(&vector_lock);

        /* Online the vector matrix array for this CPU */
        irq_matrix_online(vector_matrix);

        /*
         * The interrupt affinity logic never targets interrupts to offline
         * CPUs. The exception are the legacy PIC interrupts. In general
         * they are only targeted to CPU0, but depending on the platform
         * they can be distributed to any online CPU in hardware. The
         * kernel has no influence on that. So all active legacy vectors
         * must be installed on all CPUs. All non legacy interrupts can be
         * cleared.
         */
        for (vector = 0; vector < NR_VECTORS; vector++)
                this_cpu_write(vector_irq[vector], __setup_vector_irq(vector));
}

static void __vector_cleanup(struct vector_cleanup *cl, bool check_irr);

void lapic_offline(void)
{
        struct vector_cleanup *cl = this_cpu_ptr(&vector_cleanup);

        lock_vector_lock();

        /* In case the vector cleanup timer has not expired */
        __vector_cleanup(cl, false);

        irq_matrix_offline(vector_matrix);
        WARN_ON_ONCE(timer_delete_sync_try(&cl->timer) < 0);
        WARN_ON_ONCE(!hlist_empty(&cl->head));

        unlock_vector_lock();
}

static int apic_set_affinity(struct irq_data *irqd,
                             const struct cpumask *dest, bool force)
{
        int err;

        if (WARN_ON_ONCE(!irqd_is_activated(irqd)))
                return -EIO;

        raw_spin_lock(&vector_lock);
        cpumask_and(vector_searchmask, dest, cpu_online_mask);
        if (irqd_affinity_is_managed(irqd))
                err = assign_managed_vector(irqd, vector_searchmask);
        else
                err = assign_vector_locked(irqd, vector_searchmask);
        raw_spin_unlock(&vector_lock);
        return err ? err : IRQ_SET_MASK_OK;
}

static void free_moved_vector(struct apic_chip_data *apicd)
{
        unsigned int vector = apicd->prev_vector;
        unsigned int cpu = apicd->prev_cpu;
        bool managed = apicd->is_managed;

        /*
         * Managed interrupts are usually not migrated away
         * from an online CPU, but CPU isolation 'managed_irq'
         * can make that happen.
         * 1) Activation does not take the isolation into account
         *    to keep the code simple
         * 2) Migration away from an isolated CPU can happen when
         *    a non-isolated CPU which is in the calculated
         *    affinity mask comes online.
         */
        trace_vector_free_moved(apicd->irq, cpu, vector, managed);
        apic_free_vector(cpu, vector, managed);
        per_cpu(vector_irq, cpu)[vector] = VECTOR_UNUSED;
        hlist_del_init(&apicd->clist);
        apicd->prev_vector = 0;
        apicd->move_in_progress = 0;
}

/*
 * Called from fixup_irqs() with @desc->lock held and interrupts disabled.
 */
static void apic_force_complete_move(struct irq_data *irqd)
{
        unsigned int cpu = smp_processor_id();
        struct apic_chip_data *apicd;
        unsigned int vector;

        guard(raw_spinlock)(&vector_lock);
        apicd = apic_chip_data(irqd);
        if (!apicd)
                return;

        /*
         * If prev_vector is empty or the descriptor is neither currently
         * nor previously on the outgoing CPU no action required.
         */
        vector = apicd->prev_vector;
        if (!vector || (apicd->cpu != cpu && apicd->prev_cpu != cpu))
                return;

        /*
         * This is tricky. If the cleanup of the old vector has not been
         * done yet, then the following setaffinity call will fail with
         * -EBUSY. This can leave the interrupt in a stale state.
         *
         * All CPUs are stuck in stop machine with interrupts disabled so
         * calling __irq_complete_move() would be completely pointless.
         *
         * 1) The interrupt is in move_in_progress state. That means that we
         *    have not seen an interrupt since the io_apic was reprogrammed to
         *    the new vector.
         *
         * 2) The interrupt has fired on the new vector, but the cleanup IPIs
         *    have not been processed yet.
         */
        if (apicd->move_in_progress) {
                /*
                 * In theory there is a race:
                 *
                 * set_ioapic(new_vector) <-- Interrupt is raised before update
                 *                            is effective, i.e. it's raised on
                 *                            the old vector.
                 *
                 * So if the target cpu cannot handle that interrupt before
                 * the old vector is cleaned up, we get a spurious interrupt
                 * and in the worst case the ioapic irq line becomes stale.
                 *
                 * But in case of cpu hotplug this should be a non issue
                 * because if the affinity update happens right before all
                 * cpus rendezvous in stop machine, there is no way that the
                 * interrupt can be blocked on the target cpu because all cpus
                 * loops first with interrupts enabled in stop machine, so the
                 * old vector is not yet cleaned up when the interrupt fires.
                 *
                 * So the only way to run into this issue is if the delivery
                 * of the interrupt on the apic/system bus would be delayed
                 * beyond the point where the target cpu disables interrupts
                 * in stop machine. I doubt that it can happen, but at least
                 * there is a theoretical chance. Virtualization might be
                 * able to expose this, but AFAICT the IOAPIC emulation is not
                 * as stupid as the real hardware.
                 *
                 * Anyway, there is nothing we can do about that at this point
                 * w/o refactoring the whole fixup_irq() business completely.
                 * We print at least the irq number and the old vector number,
                 * so we have the necessary information when a problem in that
                 * area arises.
                 */
                pr_warn("IRQ fixup: irq %d move in progress, old vector %d\n",
                        irqd->irq, vector);
        }
        free_moved_vector(apicd);
}

#else
# define apic_set_affinity              NULL
# define apic_force_complete_move       NULL
#endif

static int apic_retrigger_irq(struct irq_data *irqd)
{
        struct apic_chip_data *apicd = apic_chip_data(irqd);
        unsigned long flags;

        raw_spin_lock_irqsave(&vector_lock, flags);
        __apic_send_IPI(apicd->cpu, apicd->vector);
        raw_spin_unlock_irqrestore(&vector_lock, flags);

        return 1;
}

void apic_ack_irq(struct irq_data *irqd)
{
        irq_move_irq(irqd);
        apic_eoi();
}

void apic_ack_edge(struct irq_data *irqd)
{
        irq_complete_move(irqd_cfg(irqd));
        apic_ack_irq(irqd);
}

static void x86_vector_msi_compose_msg(struct irq_data *data,
                                       struct msi_msg *msg)
{
       __irq_msi_compose_msg(irqd_cfg(data), msg, false);
}

static struct irq_chip lapic_controller = {
        .name                           = "APIC",
        .irq_ack                        = apic_ack_edge,
        .irq_set_affinity               = apic_set_affinity,
        .irq_compose_msi_msg            = x86_vector_msi_compose_msg,
        .irq_force_complete_move        = apic_force_complete_move,
        .irq_retrigger                  = apic_retrigger_irq,
};

#ifdef CONFIG_SMP

static void __vector_cleanup(struct vector_cleanup *cl, bool check_irr)
{
        struct apic_chip_data *apicd;
        struct hlist_node *tmp;
        bool rearm = false;

        lockdep_assert_held(&vector_lock);

        hlist_for_each_entry_safe(apicd, tmp, &cl->head, clist) {
                unsigned int vector = apicd->prev_vector;

                /*
                 * Paranoia: Check if the vector that needs to be cleaned
                 * up is registered at the APICs IRR. That's clearly a
                 * hardware issue if the vector arrived on the old target
                 * _after_ interrupts were disabled above. Keep @apicd
                 * on the list and schedule the timer again to give the CPU
                 * a chance to handle the pending interrupt.
                 *
                 * Do not check IRR when called from lapic_offline(), because
                 * fixup_irqs() was just called to scan IRR for set bits and
                 * forward them to new destination CPUs via IPIs.
                 */
                if (check_irr && is_vector_pending(vector)) {
                        pr_warn_once("Moved interrupt pending in old target APIC %u\n", apicd->irq);
                        rearm = true;
                        continue;
                }
                free_moved_vector(apicd);
        }

        /*
         * Must happen under vector_lock to make the timer_pending() check
         * in __vector_schedule_cleanup() race free against the rearm here.
         */
        if (rearm)
                mod_timer(&cl->timer, jiffies + 1);
}

static void vector_cleanup_callback(struct timer_list *tmr)
{
        struct vector_cleanup *cl = container_of(tmr, typeof(*cl), timer);

        /* Prevent vectors vanishing under us */
        raw_spin_lock_irq(&vector_lock);
        __vector_cleanup(cl, true);
        raw_spin_unlock_irq(&vector_lock);
}

static void __vector_schedule_cleanup(struct apic_chip_data *apicd)
{
        unsigned int cpu = apicd->prev_cpu;

        raw_spin_lock(&vector_lock);
        apicd->move_in_progress = 0;
        if (cpu_online(cpu)) {
                struct vector_cleanup *cl = per_cpu_ptr(&vector_cleanup, cpu);

                hlist_add_head(&apicd->clist, &cl->head);

                /*
                 * The lockless timer_pending() check is safe here. If it
                 * returns true, then the callback will observe this new
                 * apic data in the hlist as everything is serialized by
                 * vector lock.
                 *
                 * If it returns false then the timer is either not armed
                 * or the other CPU executes the callback, which again
                 * would be blocked on vector lock. Rearming it in the
                 * latter case makes it fire for nothing.
                 *
                 * This is also safe against the callback rearming the timer
                 * because that's serialized via vector lock too.
                 */
                if (!timer_pending(&cl->timer)) {
                        cl->timer.expires = jiffies + 1;
                        add_timer_on(&cl->timer, cpu);
                }
        } else {
                pr_warn("IRQ %u schedule cleanup for offline CPU %u\n", apicd->irq, cpu);
                free_moved_vector(apicd);
        }
        raw_spin_unlock(&vector_lock);
}

void vector_schedule_cleanup(struct irq_cfg *cfg)
{
        struct apic_chip_data *apicd;

        apicd = container_of(cfg, struct apic_chip_data, hw_irq_cfg);
        if (apicd->move_in_progress)
                __vector_schedule_cleanup(apicd);
}

void irq_complete_move(struct irq_cfg *cfg)
{
        struct apic_chip_data *apicd;

        apicd = container_of(cfg, struct apic_chip_data, hw_irq_cfg);
        if (likely(!apicd->move_in_progress))
                return;

        /*
         * If the interrupt arrived on the new target CPU, cleanup the
         * vector on the old target CPU. A vector check is not required
         * because an interrupt can never move from one vector to another
         * on the same CPU.
         */
        if (apicd->cpu == smp_processor_id())
                __vector_schedule_cleanup(apicd);
}

#ifdef CONFIG_HOTPLUG_CPU
/*
 * Note, this is not accurate accounting, but at least good enough to
 * prevent that the actual interrupt move will run out of vectors.
 */
int lapic_can_unplug_cpu(void)
{
        unsigned int rsvd, avl, tomove, cpu = smp_processor_id();
        int ret = 0;

        raw_spin_lock(&vector_lock);
        tomove = irq_matrix_allocated(vector_matrix);
        avl = irq_matrix_available(vector_matrix, true);
        if (avl < tomove) {
                pr_warn("CPU %u has %u vectors, %u available. Cannot disable CPU\n",
                        cpu, tomove, avl);
                ret = -ENOSPC;
                goto out;
        }
        rsvd = irq_matrix_reserved(vector_matrix);
        if (avl < rsvd) {
                pr_warn("Reserved vectors %u > available %u. IRQ request may fail\n",
                        rsvd, avl);
        }
out:
        raw_spin_unlock(&vector_lock);
        return ret;
}
#endif /* HOTPLUG_CPU */
#endif /* SMP */

static void __init print_APIC_field(int base)
{
        int i;

        printk(KERN_DEBUG);

        for (i = 0; i < 8; i++)
                pr_cont("%08x", apic_read(base + i*0x10));

        pr_cont("\n");
}

static void __init print_local_APIC(void *dummy)
{
        unsigned int i, v, ver, maxlvt;
        u64 icr;

        pr_debug("printing local APIC contents on CPU#%d/%d:\n",
                 smp_processor_id(), read_apic_id());
        v = apic_read(APIC_ID);
        pr_info("... APIC ID:      %08x (%01x)\n", v, read_apic_id());
        v = apic_read(APIC_LVR);
        pr_info("... APIC VERSION: %08x\n", v);
        ver = GET_APIC_VERSION(v);
        maxlvt = lapic_get_maxlvt();

        v = apic_read(APIC_TASKPRI);
        pr_debug("... APIC TASKPRI: %08x (%02x)\n", v, v & APIC_TPRI_MASK);

        /* !82489DX */
        if (APIC_INTEGRATED(ver)) {
                if (!APIC_XAPIC(ver)) {
                        v = apic_read(APIC_ARBPRI);
                        pr_debug("... APIC ARBPRI: %08x (%02x)\n",
                                 v, v & APIC_ARBPRI_MASK);
                }
                v = apic_read(APIC_PROCPRI);
                pr_debug("... APIC PROCPRI: %08x\n", v);
        }

        /*
         * Remote read supported only in the 82489DX and local APIC for
         * Pentium processors.
         */
        if (!APIC_INTEGRATED(ver) || maxlvt == 3) {
                v = apic_read(APIC_RRR);
                pr_debug("... APIC RRR: %08x\n", v);
        }

        v = apic_read(APIC_LDR);
        pr_debug("... APIC LDR: %08x\n", v);
        if (!x2apic_enabled()) {
                v = apic_read(APIC_DFR);
                pr_debug("... APIC DFR: %08x\n", v);
        }
        v = apic_read(APIC_SPIV);
        pr_debug("... APIC SPIV: %08x\n", v);

        pr_debug("... APIC ISR field:\n");
        print_APIC_field(APIC_ISR);
        pr_debug("... APIC TMR field:\n");
        print_APIC_field(APIC_TMR);
        pr_debug("... APIC IRR field:\n");
        print_APIC_field(APIC_IRR);

        /* !82489DX */
        if (APIC_INTEGRATED(ver)) {
                /* Due to the Pentium erratum 3AP. */
                if (maxlvt > 3)
                        apic_write(APIC_ESR, 0);

                v = apic_read(APIC_ESR);
                pr_debug("... APIC ESR: %08x\n", v);
        }

        icr = apic_icr_read();
        pr_debug("... APIC ICR: %08x\n", (u32)icr);
        pr_debug("... APIC ICR2: %08x\n", (u32)(icr >> 32));

        v = apic_read(APIC_LVTT);
        pr_debug("... APIC LVTT: %08x\n", v);

        if (maxlvt > 3) {
                /* PC is LVT#4. */
                v = apic_read(APIC_LVTPC);
                pr_debug("... APIC LVTPC: %08x\n", v);
        }
        v = apic_read(APIC_LVT0);
        pr_debug("... APIC LVT0: %08x\n", v);
        v = apic_read(APIC_LVT1);
        pr_debug("... APIC LVT1: %08x\n", v);

        if (maxlvt > 2) {
                /* ERR is LVT#3. */
                v = apic_read(APIC_LVTERR);
                pr_debug("... APIC LVTERR: %08x\n", v);
        }

        v = apic_read(APIC_TMICT);
        pr_debug("... APIC TMICT: %08x\n", v);
        v = apic_read(APIC_TMCCT);
        pr_debug("... APIC TMCCT: %08x\n", v);
        v = apic_read(APIC_TDCR);
        pr_debug("... APIC TDCR: %08x\n", v);

        if (boot_cpu_has(X86_FEATURE_EXTAPIC)) {
                v = apic_read(APIC_EFEAT);
                maxlvt = (v >> 16) & 0xff;
                pr_debug("... APIC EFEAT: %08x\n", v);
                v = apic_read(APIC_ECTRL);
                pr_debug("... APIC ECTRL: %08x\n", v);
                for (i = 0; i < maxlvt; i++) {
                        v = apic_read(APIC_EILVTn(i));
                        pr_debug("... APIC EILVT%d: %08x\n", i, v);
                }
        }
        pr_cont("\n");
}

static void __init print_local_APICs(int maxcpu)
{
        int cpu;

        if (!maxcpu)
                return;

        preempt_disable();
        for_each_online_cpu(cpu) {
                if (cpu >= maxcpu)
                        break;
                smp_call_function_single(cpu, print_local_APIC, NULL, 1);
        }
        preempt_enable();
}

static void __init print_PIC(void)
{
        unsigned int v;
        unsigned long flags;

        if (!nr_legacy_irqs())
                return;

        pr_debug("\nprinting PIC contents\n");

        raw_spin_lock_irqsave(&i8259A_lock, flags);

        v = inb(0xa1) << 8 | inb(0x21);
        pr_debug("... PIC  IMR: %04x\n", v);

        v = inb(0xa0) << 8 | inb(0x20);
        pr_debug("... PIC  IRR: %04x\n", v);

        outb(0x0b, 0xa0);
        outb(0x0b, 0x20);
        v = inb(0xa0) << 8 | inb(0x20);
        outb(0x0a, 0xa0);
        outb(0x0a, 0x20);

        raw_spin_unlock_irqrestore(&i8259A_lock, flags);

        pr_debug("... PIC  ISR: %04x\n", v);

        v = inb(PIC_ELCR2) << 8 | inb(PIC_ELCR1);
        pr_debug("... PIC ELCR: %04x\n", v);
}

static int show_lapic __initdata = 1;
static __init int setup_show_lapic(char *arg)
{
        int num = -1;

        if (strcmp(arg, "all") == 0) {
                show_lapic = CONFIG_NR_CPUS;
        } else {
                get_option(&arg, &num);
                if (num >= 0)
                        show_lapic = num;
        }

        return 1;
}
__setup("show_lapic=", setup_show_lapic);

static int __init print_ICs(void)
{
        if (apic_verbosity == APIC_QUIET)
                return 0;

        print_PIC();

        /* don't print out if apic is not there */
        if (!boot_cpu_has(X86_FEATURE_APIC) && !apic_from_smp_config())
                return 0;

        print_local_APICs(show_lapic);
        print_IO_APICs();

        return 0;
}

late_initcall(print_ICs);
Linux
