x86/speculation/mds: Fix documentation typo

[linux/fpc-iii.git] / arch / x86 / kernel / apic / vector.c

/*
 * Local APIC related interfaces to support IOAPIC, MSI, HT_IRQ 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
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/slab.h>
#include <asm/irqdomain.h>
#include <asm/hw_irq.h>
#include <asm/apic.h>
#include <asm/i8259.h>
#include <asm/desc.h>
#include <asm/irq_remapping.h>

struct apic_chip_data {
        struct irq_cfg          cfg;
        cpumask_var_t           domain;
        cpumask_var_t           old_domain;
        u8                      move_in_progress : 1;
};

struct irq_domain *x86_vector_domain;
EXPORT_SYMBOL_GPL(x86_vector_domain);
static DEFINE_RAW_SPINLOCK(vector_lock);
static cpumask_var_t vector_cpumask, vector_searchmask, searched_cpumask;
static struct irq_chip lapic_controller;
#ifdef  CONFIG_X86_IO_APIC
static struct apic_chip_data *legacy_irq_data[NR_IRQS_LEGACY];
#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);
}

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

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

        return irq_data->chip_data;
}

struct irq_cfg *irqd_cfg(struct irq_data *irq_data)
{
        struct apic_chip_data *data = apic_chip_data(irq_data);

        return data ? &data->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 *data;

        data = kzalloc_node(sizeof(*data), GFP_KERNEL, node);
        if (!data)
                return NULL;
        if (!zalloc_cpumask_var_node(&data->domain, GFP_KERNEL, node))
                goto out_data;
        if (!zalloc_cpumask_var_node(&data->old_domain, GFP_KERNEL, node))
                goto out_domain;
        return data;
out_domain:
        free_cpumask_var(data->domain);
out_data:
        kfree(data);
        return NULL;
}

static void free_apic_chip_data(struct apic_chip_data *data)
{
        if (data) {
                free_cpumask_var(data->domain);
                free_cpumask_var(data->old_domain);
                kfree(data);
        }
}

static int __assign_irq_vector(int irq, struct apic_chip_data *d,
                               const struct cpumask *mask,
                               struct irq_data *irqdata)
{
        /*
         * NOTE! The local APIC isn't very good at handling
         * multiple interrupts at the same interrupt level.
         * As the interrupt level is determined by taking the
         * vector number and shifting that right by 4, we
         * want to spread these out a bit so that they don't
         * all fall in the same interrupt level.
         *
         * Also, we've got to be careful not to trash gate
         * 0x80, because int 0x80 is hm, kind of importantish. ;)
         */
        static int current_vector = FIRST_EXTERNAL_VECTOR + VECTOR_OFFSET_START;
        static int current_offset = VECTOR_OFFSET_START % 16;
        int cpu, vector;

        /*
         * If there is still a move in progress or the previous move has not
         * been cleaned up completely, tell the caller to come back later.
         */
        if (d->move_in_progress ||
            cpumask_intersects(d->old_domain, cpu_online_mask))
                return -EBUSY;

        /* Only try and allocate irqs on cpus that are present */
        cpumask_clear(d->old_domain);
        cpumask_clear(searched_cpumask);
        cpu = cpumask_first_and(mask, cpu_online_mask);
        while (cpu < nr_cpu_ids) {
                int new_cpu, offset;

                /* Get the possible target cpus for @mask/@cpu from the apic */
                apic->vector_allocation_domain(cpu, vector_cpumask, mask);

                /*
                 * Clear the offline cpus from @vector_cpumask for searching
                 * and verify whether the result overlaps with @mask. If true,
                 * then the call to apic->cpu_mask_to_apicid() will
                 * succeed as well. If not, no point in trying to find a
                 * vector in this mask.
                 */
                cpumask_and(vector_searchmask, vector_cpumask, cpu_online_mask);
                if (!cpumask_intersects(vector_searchmask, mask))
                        goto next_cpu;

                if (cpumask_subset(vector_cpumask, d->domain)) {
                        if (cpumask_equal(vector_cpumask, d->domain))
                                goto success;
                        /*
                         * Mark the cpus which are not longer in the mask for
                         * cleanup.
                         */
                        cpumask_andnot(d->old_domain, d->domain, vector_cpumask);
                        vector = d->cfg.vector;
                        goto update;
                }

                vector = current_vector;
                offset = current_offset;
next:
                vector += 16;
                if (vector >= FIRST_SYSTEM_VECTOR) {
                        offset = (offset + 1) % 16;
                        vector = FIRST_EXTERNAL_VECTOR + offset;
                }

                /* If the search wrapped around, try the next cpu */
                if (unlikely(current_vector == vector))
                        goto next_cpu;

                if (test_bit(vector, used_vectors))
                        goto next;

                for_each_cpu(new_cpu, vector_searchmask) {
                        if (!IS_ERR_OR_NULL(per_cpu(vector_irq, new_cpu)[vector]))
                                goto next;
                }
                /* Found one! */
                current_vector = vector;
                current_offset = offset;
                /* Schedule the old vector for cleanup on all cpus */
                if (d->cfg.vector)
                        cpumask_copy(d->old_domain, d->domain);
                for_each_cpu(new_cpu, vector_searchmask)
                        per_cpu(vector_irq, new_cpu)[vector] = irq_to_desc(irq);
                goto update;

next_cpu:
                /*
                 * We exclude the current @vector_cpumask from the requested
                 * @mask and try again with the next online cpu in the
                 * result. We cannot modify @mask, so we use @vector_cpumask
                 * as a temporary buffer here as it will be reassigned when
                 * calling apic->vector_allocation_domain() above.
                 */
                cpumask_or(searched_cpumask, searched_cpumask, vector_cpumask);
                cpumask_andnot(vector_cpumask, mask, searched_cpumask);
                cpu = cpumask_first_and(vector_cpumask, cpu_online_mask);
                continue;
        }
        return -ENOSPC;

update:
        /*
         * Exclude offline cpus from the cleanup mask and set the
         * move_in_progress flag when the result is not empty.
         */
        cpumask_and(d->old_domain, d->old_domain, cpu_online_mask);
        d->move_in_progress = !cpumask_empty(d->old_domain);
        d->cfg.old_vector = d->move_in_progress ? d->cfg.vector : 0;
        d->cfg.vector = vector;
        cpumask_copy(d->domain, vector_cpumask);
success:
        /*
         * Cache destination APIC IDs into cfg->dest_apicid. This cannot fail
         * as we already established, that mask & d->domain & cpu_online_mask
         * is not empty.
         *
         * vector_searchmask is a subset of d->domain and has the offline
         * cpus masked out.
         */
        cpumask_and(vector_searchmask, vector_searchmask, mask);
        BUG_ON(apic->cpu_mask_to_apicid(vector_searchmask, irqdata,
                                        &d->cfg.dest_apicid));
        return 0;
}

static int assign_irq_vector(int irq, struct apic_chip_data *data,
                             const struct cpumask *mask,
                             struct irq_data *irqdata)
{
        int err;
        unsigned long flags;

        raw_spin_lock_irqsave(&vector_lock, flags);
        err = __assign_irq_vector(irq, data, mask, irqdata);
        raw_spin_unlock_irqrestore(&vector_lock, flags);
        return err;
}

static int assign_irq_vector_policy(int irq, int node,
                                    struct apic_chip_data *data,
                                    struct irq_alloc_info *info,
                                    struct irq_data *irqdata)
{
        if (info && info->mask)
                return assign_irq_vector(irq, data, info->mask, irqdata);
        if (node != NUMA_NO_NODE &&
            assign_irq_vector(irq, data, cpumask_of_node(node), irqdata) == 0)
                return 0;
        return assign_irq_vector(irq, data, apic->target_cpus(), irqdata);
}

static void clear_irq_vector(int irq, struct apic_chip_data *data)
{
        struct irq_desc *desc;
        int cpu, vector;

        if (!data->cfg.vector)
                return;

        vector = data->cfg.vector;
        for_each_cpu_and(cpu, data->domain, cpu_online_mask)
                per_cpu(vector_irq, cpu)[vector] = VECTOR_UNUSED;

        data->cfg.vector = 0;
        cpumask_clear(data->domain);

        /*
         * If move is in progress or the old_domain mask is not empty,
         * i.e. the cleanup IPI has not been processed yet, we need to remove
         * the old references to desc from all cpus vector tables.
         */
        if (!data->move_in_progress && cpumask_empty(data->old_domain))
                return;

        desc = irq_to_desc(irq);
        for_each_cpu_and(cpu, data->old_domain, cpu_online_mask) {
                for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS;
                     vector++) {
                        if (per_cpu(vector_irq, cpu)[vector] != desc)
                                continue;
                        per_cpu(vector_irq, cpu)[vector] = VECTOR_UNUSED;
                        break;
                }
        }
        data->move_in_progress = 0;
}

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

        for (i = 0; i < nr_irqs; i++) {
                irq_data = irq_domain_get_irq_data(x86_vector_domain, virq + i);
                if (irq_data && irq_data->chip_data) {
                        raw_spin_lock_irqsave(&vector_lock, flags);
                        clear_irq_vector(virq + i, irq_data->chip_data);
                        apic_data = irq_data->chip_data;
                        irq_domain_reset_irq_data(irq_data);
                        raw_spin_unlock_irqrestore(&vector_lock, flags);
                        free_apic_chip_data(apic_data);
#ifdef  CONFIG_X86_IO_APIC
                        if (virq + i < nr_legacy_irqs())
                                legacy_irq_data[virq + i] = NULL;
#endif
                }
        }
}

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 *data;
        struct irq_data *irq_data;
        int i, err, node;

        if (disable_apic)
                return -ENXIO;

        /* Currently vector allocator can't guarantee contiguous allocations */
        if ((info->flags & X86_IRQ_ALLOC_CONTIGUOUS_VECTORS) && nr_irqs > 1)
                return -ENOSYS;

        for (i = 0; i < nr_irqs; i++) {
                irq_data = irq_domain_get_irq_data(domain, virq + i);
                BUG_ON(!irq_data);
                node = irq_data_get_node(irq_data);
#ifdef  CONFIG_X86_IO_APIC
                if (virq + i < nr_legacy_irqs() && legacy_irq_data[virq + i])
                        data = legacy_irq_data[virq + i];
                else
#endif
                        data = alloc_apic_chip_data(node);
                if (!data) {
                        err = -ENOMEM;
                        goto error;
                }

                irq_data->chip = &lapic_controller;
                irq_data->chip_data = data;
                irq_data->hwirq = virq + i;
                err = assign_irq_vector_policy(virq + i, node, data, info,
                                               irq_data);
                if (err) {
                        irq_data->chip_data = NULL;
                        free_apic_chip_data(data);
                        goto error;
                }
                /*
                 * If the apic destination mode is physical, then the
                 * effective affinity is restricted to a single target
                 * CPU. Mark the interrupt accordingly.
                 */
                if (!apic->irq_dest_mode)
                        irqd_set_single_target(irq_data);
        }

        return 0;

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

static const struct irq_domain_ops x86_vector_domain_ops = {
        .alloc  = x86_vector_alloc_irqs,
        .free   = x86_vector_free_irqs,
};

int __init arch_probe_nr_irqs(void)
{
        int nr;

        if (nr_irqs > (NR_VECTORS * nr_cpu_ids))
                nr_irqs = NR_VECTORS * nr_cpu_ids;

        nr = (gsi_top + nr_legacy_irqs()) + 8 * nr_cpu_ids;
#if defined(CONFIG_PCI_MSI) || defined(CONFIG_HT_IRQ)
        /*
         * 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 < nr_irqs)
                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();
}

#ifdef  CONFIG_X86_IO_APIC
static void __init init_legacy_irqs(void)
{
        int i, node = cpu_to_node(0);
        struct apic_chip_data *data;

        /*
         * For legacy IRQ's, start with assigning irq0 to irq15 to
         * ISA_IRQ_VECTOR(i) for all cpu's.
         */
        for (i = 0; i < nr_legacy_irqs(); i++) {
                data = legacy_irq_data[i] = alloc_apic_chip_data(node);
                BUG_ON(!data);

                data->cfg.vector = ISA_IRQ_VECTOR(i);
                cpumask_setall(data->domain);
                irq_set_chip_data(i, data);
        }
}
#else
static inline void init_legacy_irqs(void) { }
#endif

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

        init_legacy_irqs();

        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_domain_free_fwnode(fn);
        irq_set_default_host(x86_vector_domain);

        arch_init_msi_domain(x86_vector_domain);
        arch_init_htirq_domain(x86_vector_domain);

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

        return arch_early_ioapic_init();
}

/* Initialize vector_irq on a new cpu */
static void __setup_vector_irq(int cpu)
{
        struct apic_chip_data *data;
        struct irq_desc *desc;
        int irq, vector;

        /* Mark the inuse vectors */
        for_each_irq_desc(irq, desc) {
                struct irq_data *idata = irq_desc_get_irq_data(desc);

                data = apic_chip_data(idata);
                if (!data || !cpumask_test_cpu(cpu, data->domain))
                        continue;
                vector = data->cfg.vector;
                per_cpu(vector_irq, cpu)[vector] = desc;
        }
        /* Mark the free vectors */
        for (vector = 0; vector < NR_VECTORS; ++vector) {
                desc = per_cpu(vector_irq, cpu)[vector];
                if (IS_ERR_OR_NULL(desc))
                        continue;

                data = apic_chip_data(irq_desc_get_irq_data(desc));
                if (!cpumask_test_cpu(cpu, data->domain))
                        per_cpu(vector_irq, cpu)[vector] = VECTOR_UNUSED;
        }
}

/*
 * Setup the vector to irq mappings. Must be called with vector_lock held.
 */
void setup_vector_irq(int cpu)
{
        int irq;

        lockdep_assert_held(&vector_lock);
        /*
         * On most of the platforms, legacy PIC delivers the interrupts on the
         * boot cpu. But there are certain platforms where PIC interrupts are
         * delivered to multiple cpu's. If the legacy IRQ is handled by the
         * legacy PIC, for the new cpu that is coming online, setup the static
         * legacy vector to irq mapping:
         */
        for (irq = 0; irq < nr_legacy_irqs(); irq++)
                per_cpu(vector_irq, cpu)[ISA_IRQ_VECTOR(irq)] = irq_to_desc(irq);

        __setup_vector_irq(cpu);
}

static int apic_retrigger_irq(struct irq_data *irq_data)
{
        struct apic_chip_data *data = apic_chip_data(irq_data);
        unsigned long flags;
        int cpu;

        raw_spin_lock_irqsave(&vector_lock, flags);
        cpu = cpumask_first_and(data->domain, cpu_online_mask);
        apic->send_IPI_mask(cpumask_of(cpu), data->cfg.vector);
        raw_spin_unlock_irqrestore(&vector_lock, flags);

        return 1;
}

void apic_ack_edge(struct irq_data *data)
{
        irq_complete_move(irqd_cfg(data));
        irq_move_irq(data);
        ack_APIC_irq();
}

static int apic_set_affinity(struct irq_data *irq_data,
                             const struct cpumask *dest, bool force)
{
        struct apic_chip_data *data = irq_data->chip_data;
        int err, irq = irq_data->irq;

        if (!IS_ENABLED(CONFIG_SMP))
                return -EPERM;

        if (!cpumask_intersects(dest, cpu_online_mask))
                return -EINVAL;

        err = assign_irq_vector(irq, data, dest, irq_data);
        return err ? err : IRQ_SET_MASK_OK;
}

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

#ifdef CONFIG_SMP
static void __send_cleanup_vector(struct apic_chip_data *data)
{
        raw_spin_lock(&vector_lock);
        cpumask_and(data->old_domain, data->old_domain, cpu_online_mask);
        data->move_in_progress = 0;
        if (!cpumask_empty(data->old_domain))
                apic->send_IPI_mask(data->old_domain, IRQ_MOVE_CLEANUP_VECTOR);
        raw_spin_unlock(&vector_lock);
}

void send_cleanup_vector(struct irq_cfg *cfg)
{
        struct apic_chip_data *data;

        data = container_of(cfg, struct apic_chip_data, cfg);
        if (data->move_in_progress)
                __send_cleanup_vector(data);
}

asmlinkage __visible void __irq_entry smp_irq_move_cleanup_interrupt(void)
{
        unsigned vector, me;

        entering_ack_irq();

        /* Prevent vectors vanishing under us */
        raw_spin_lock(&vector_lock);

        me = smp_processor_id();
        for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
                struct apic_chip_data *data;
                struct irq_desc *desc;
                unsigned int irr;

        retry:
                desc = __this_cpu_read(vector_irq[vector]);
                if (IS_ERR_OR_NULL(desc))
                        continue;

                if (!raw_spin_trylock(&desc->lock)) {
                        raw_spin_unlock(&vector_lock);
                        cpu_relax();
                        raw_spin_lock(&vector_lock);
                        goto retry;
                }

                data = apic_chip_data(irq_desc_get_irq_data(desc));
                if (!data)
                        goto unlock;

                /*
                 * Nothing to cleanup if irq migration is in progress
                 * or this cpu is not set in the cleanup mask.
                 */
                if (data->move_in_progress ||
                    !cpumask_test_cpu(me, data->old_domain))
                        goto unlock;

                /*
                 * We have two cases to handle here:
                 * 1) vector is unchanged but the target mask got reduced
                 * 2) vector and the target mask has changed
                 *
                 * #1 is obvious, but in #2 we have two vectors with the same
                 * irq descriptor: the old and the new vector. So we need to
                 * make sure that we only cleanup the old vector. The new
                 * vector has the current @vector number in the config and
                 * this cpu is part of the target mask. We better leave that
                 * one alone.
                 */
                if (vector == data->cfg.vector &&
                    cpumask_test_cpu(me, data->domain))
                        goto unlock;

                irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
                /*
                 * Check if the vector that needs to be cleanedup is
                 * registered at the cpu's IRR. If so, then this is not
                 * the best time to clean it up. Lets clean it up in the
                 * next attempt by sending another IRQ_MOVE_CLEANUP_VECTOR
                 * to myself.
                 */
                if (irr  & (1 << (vector % 32))) {
                        apic->send_IPI_self(IRQ_MOVE_CLEANUP_VECTOR);
                        goto unlock;
                }
                __this_cpu_write(vector_irq[vector], VECTOR_UNUSED);
                cpumask_clear_cpu(me, data->old_domain);
unlock:
                raw_spin_unlock(&desc->lock);
        }

        raw_spin_unlock(&vector_lock);

        exiting_irq();
}

static void __irq_complete_move(struct irq_cfg *cfg, unsigned vector)
{
        unsigned me;
        struct apic_chip_data *data;

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

        me = smp_processor_id();
        if (vector == data->cfg.vector && cpumask_test_cpu(me, data->domain))
                __send_cleanup_vector(data);
}

void irq_complete_move(struct irq_cfg *cfg)
{
        __irq_complete_move(cfg, ~get_irq_regs()->orig_ax);
}

/*
 * Called from fixup_irqs() with @desc->lock held and interrupts disabled.
 */
void irq_force_complete_move(struct irq_desc *desc)
{
        struct irq_data *irqdata;
        struct apic_chip_data *data;
        struct irq_cfg *cfg;
        unsigned int cpu;

        /*
         * The function is called for all descriptors regardless of which
         * irqdomain they belong to. For example if an IRQ is provided by
         * an irq_chip as part of a GPIO driver, the chip data for that
         * descriptor is specific to the irq_chip in question.
         *
         * Check first that the chip_data is what we expect
         * (apic_chip_data) before touching it any further.
         */
        irqdata = irq_domain_get_irq_data(x86_vector_domain,
                                          irq_desc_get_irq(desc));
        if (!irqdata)
                return;

        data = apic_chip_data(irqdata);
        cfg = data ? &data->cfg : NULL;

        if (!cfg)
                return;

        /*
         * This is tricky. If the cleanup of @data->old_domain 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.
         */
        raw_spin_lock(&vector_lock);
        /*
         * Clean out all offline cpus (including the outgoing one) from the
         * old_domain mask.
         */
        cpumask_and(data->old_domain, data->old_domain, cpu_online_mask);

        /*
         * If move_in_progress is cleared and the old_domain mask is empty,
         * then there is nothing to cleanup. fixup_irqs() will take care of
         * the stale vectors on the outgoing cpu.
         */
        if (!data->move_in_progress && cpumask_empty(data->old_domain)) {
                raw_spin_unlock(&vector_lock);
                return;
        }

        /*
         * 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 (data->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 rendevouz 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 theroretical 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",
                        irqdata->irq, cfg->old_vector);
        }
        /*
         * If old_domain is not empty, then other cpus still have the irq
         * descriptor set in their vector array. Clean it up.
         */
        for_each_cpu(cpu, data->old_domain)
                per_cpu(vector_irq, cpu)[cfg->old_vector] = VECTOR_UNUSED;

        /* Cleanup the left overs of the (half finished) move */
        cpumask_clear(data->old_domain);
        data->move_in_progress = 0;
        raw_spin_unlock(&vector_lock);
}
#endif

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(), hard_smp_processor_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(0x4d1) << 8 | inb(0x4d0);
        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);