arch/x86/kernel/irq.c - arm/linux - Git at Google

 /*
  * Common interrupt code for 32 and 64 bit
  */
 #include <linux/cpu.h>
 #include <linux/interrupt.h>
 #include <linux/kernel_stat.h>
 #include <linux/of.h>
 #include <linux/seq_file.h>
 #include <linux/smp.h>
 #include <linux/ftrace.h>
 #include <linux/delay.h>
 #include <linux/export.h>

 #include <asm/apic.h>
 #include <asm/io_apic.h>
 #include <asm/irq.h>
 #include <asm/mce.h>
 #include <asm/hw_irq.h>
 #include <asm/desc.h>

 #define CREATE_TRACE_POINTS
 #include <asm/trace/irq_vectors.h>

 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
 EXPORT_PER_CPU_SYMBOL(irq_stat);

 DEFINE_PER_CPU(struct pt_regs *, irq_regs);
 EXPORT_PER_CPU_SYMBOL(irq_regs);

 atomic_t irq_err_count;

 /* Function pointer for generic interrupt vector handling */
 void (*x86_platform_ipi_callback)(void) = NULL;

 /*
  * 'what should we do if we get a hw irq event on an illegal vector'.
  * each architecture has to answer this themselves.
  */
 void ack_bad_irq(unsigned int irq)
 {
 	if (printk_ratelimit())
 		pr_err("unexpected IRQ trap at vector %02x\n", irq);

 	/*
 	 * Currently unexpected vectors happen only on SMP and APIC.
 	 * We _must_ ack these because every local APIC has only N
 	 * irq slots per priority level, and a 'hanging, unacked' IRQ
 	 * holds up an irq slot - in excessive cases (when multiple
 	 * unexpected vectors occur) that might lock up the APIC
 	 * completely.
 	 * But only ack when the APIC is enabled -AK
 	 */
 	ack_APIC_irq();
 }

 #define irq_stats(x)		(&per_cpu(irq_stat, x))
 /*
  * /proc/interrupts printing for arch specific interrupts
  */
 int arch_show_interrupts(struct seq_file *p, int prec)
 {
 	int j;

 	seq_printf(p, "%*s: ", prec, "NMI");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->__nmi_count);
 	seq_puts(p, "  Non-maskable interrupts\n");
 #ifdef CONFIG_X86_LOCAL_APIC
 	seq_printf(p, "%*s: ", prec, "LOC");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->apic_timer_irqs);
 	seq_puts(p, "  Local timer interrupts\n");

 	seq_printf(p, "%*s: ", prec, "SPU");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->irq_spurious_count);
 	seq_puts(p, "  Spurious interrupts\n");
 	seq_printf(p, "%*s: ", prec, "PMI");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->apic_perf_irqs);
 	seq_puts(p, "  Performance monitoring interrupts\n");
 	seq_printf(p, "%*s: ", prec, "IWI");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->apic_irq_work_irqs);
 	seq_puts(p, "  IRQ work interrupts\n");
 	seq_printf(p, "%*s: ", prec, "RTR");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->icr_read_retry_count);
 	seq_puts(p, "  APIC ICR read retries\n");
 #endif
 	if (x86_platform_ipi_callback) {
 		seq_printf(p, "%*s: ", prec, "PLT");
 		for_each_online_cpu(j)
 			seq_printf(p, "%10u ", irq_stats(j)->x86_platform_ipis);
 		seq_puts(p, "  Platform interrupts\n");
 	}
 #ifdef CONFIG_SMP
 	seq_printf(p, "%*s: ", prec, "RES");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
 	seq_puts(p, "  Rescheduling interrupts\n");
 	seq_printf(p, "%*s: ", prec, "CAL");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->irq_call_count);
 	seq_puts(p, "  Function call interrupts\n");
 	seq_printf(p, "%*s: ", prec, "TLB");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
 	seq_puts(p, "  TLB shootdowns\n");
 #endif
 #ifdef CONFIG_X86_THERMAL_VECTOR
 	seq_printf(p, "%*s: ", prec, "TRM");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->irq_thermal_count);
 	seq_puts(p, "  Thermal event interrupts\n");
 #endif
 #ifdef CONFIG_X86_MCE_THRESHOLD
 	seq_printf(p, "%*s: ", prec, "THR");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->irq_threshold_count);
 	seq_puts(p, "  Threshold APIC interrupts\n");
 #endif
 #ifdef CONFIG_X86_MCE_AMD
 	seq_printf(p, "%*s: ", prec, "DFR");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->irq_deferred_error_count);
 	seq_puts(p, "  Deferred Error APIC interrupts\n");
 #endif
 #ifdef CONFIG_X86_MCE
 	seq_printf(p, "%*s: ", prec, "MCE");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", per_cpu(mce_exception_count, j));
 	seq_puts(p, "  Machine check exceptions\n");
 	seq_printf(p, "%*s: ", prec, "MCP");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", per_cpu(mce_poll_count, j));
 	seq_puts(p, "  Machine check polls\n");
 #endif
 #if IS_ENABLED(CONFIG_HYPERV) || defined(CONFIG_XEN)
 	if (test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors)) {
 		seq_printf(p, "%*s: ", prec, "HYP");
 		for_each_online_cpu(j)
 			seq_printf(p, "%10u ",
 				   irq_stats(j)->irq_hv_callback_count);
 		seq_puts(p, "  Hypervisor callback interrupts\n");
 	}
 #endif
 	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
 #if defined(CONFIG_X86_IO_APIC)
 	seq_printf(p, "%*s: %10u\n", prec, "MIS", atomic_read(&irq_mis_count));
 #endif
 #ifdef CONFIG_HAVE_KVM
 	seq_printf(p, "%*s: ", prec, "PIN");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->kvm_posted_intr_ipis);
 	seq_puts(p, "  Posted-interrupt notification event\n");

 	seq_printf(p, "%*s: ", prec, "PIW");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ",
 			   irq_stats(j)->kvm_posted_intr_wakeup_ipis);
 	seq_puts(p, "  Posted-interrupt wakeup event\n");
 #endif
 	return 0;
 }

 /*
  * /proc/stat helpers
  */
 u64 arch_irq_stat_cpu(unsigned int cpu)
 {
 	u64 sum = irq_stats(cpu)->__nmi_count;

 #ifdef CONFIG_X86_LOCAL_APIC
 	sum += irq_stats(cpu)->apic_timer_irqs;
 	sum += irq_stats(cpu)->irq_spurious_count;
 	sum += irq_stats(cpu)->apic_perf_irqs;
 	sum += irq_stats(cpu)->apic_irq_work_irqs;
 	sum += irq_stats(cpu)->icr_read_retry_count;
 #endif
 	if (x86_platform_ipi_callback)
 		sum += irq_stats(cpu)->x86_platform_ipis;
 #ifdef CONFIG_SMP
 	sum += irq_stats(cpu)->irq_resched_count;
 	sum += irq_stats(cpu)->irq_call_count;
 #endif
 #ifdef CONFIG_X86_THERMAL_VECTOR
 	sum += irq_stats(cpu)->irq_thermal_count;
 #endif
 #ifdef CONFIG_X86_MCE_THRESHOLD
 	sum += irq_stats(cpu)->irq_threshold_count;
 #endif
 #ifdef CONFIG_X86_MCE
 	sum += per_cpu(mce_exception_count, cpu);
 	sum += per_cpu(mce_poll_count, cpu);
 #endif
 	return sum;
 }

 u64 arch_irq_stat(void)
 {
 	u64 sum = atomic_read(&irq_err_count);
 	return sum;
 }


 /*
  * do_IRQ handles all normal device IRQ's (the special
  * SMP cross-CPU interrupts have their own specific
  * handlers).
  */
 __visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
 	struct irq_desc * desc;
 	/* high bit used in ret_from_ code  */
 	unsigned vector = ~regs->orig_ax;

 	/*
 	 * NB: Unlike exception entries, IRQ entries do not reliably
 	 * handle context tracking in the low-level entry code.  This is
 	 * because syscall entries execute briefly with IRQs on before
 	 * updating context tracking state, so we can take an IRQ from
 	 * kernel mode with CONTEXT_USER.  The low-level entry code only
 	 * updates the context if we came from user mode, so we won't
 	 * switch to CONTEXT_KERNEL.  We'll fix that once the syscall
 	 * code is cleaned up enough that we can cleanly defer enabling
 	 * IRQs.
 	 */

 	entering_irq();

 	/* entering_irq() tells RCU that we're not quiescent.  Check it. */
 	RCU_LOCKDEP_WARN(!rcu_is_watching(), "IRQ failed to wake up RCU");

 	desc = __this_cpu_read(vector_irq[vector]);

 	if (!handle_irq(desc, regs)) {
 		ack_APIC_irq();

 		if (desc != VECTOR_RETRIGGERED) {
 			pr_emerg_ratelimited("%s: %d.%d No irq handler for vector\n",
 					     __func__, smp_processor_id(),
 					     vector);
 		} else {
 			__this_cpu_write(vector_irq[vector], VECTOR_UNUSED);
 		}
 	}

 	exiting_irq();

 	set_irq_regs(old_regs);
 	return 1;
 }

 /*
  * Handler for X86_PLATFORM_IPI_VECTOR.
  */
 void __smp_x86_platform_ipi(void)
 {
 	inc_irq_stat(x86_platform_ipis);

 	if (x86_platform_ipi_callback)
 		x86_platform_ipi_callback();
 }

 __visible void __irq_entry smp_x86_platform_ipi(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);

 	entering_ack_irq();
 	__smp_x86_platform_ipi();
 	exiting_irq();
 	set_irq_regs(old_regs);
 }

 #ifdef CONFIG_HAVE_KVM
 static void dummy_handler(void) {}
 static void (*kvm_posted_intr_wakeup_handler)(void) = dummy_handler;

 void kvm_set_posted_intr_wakeup_handler(void (*handler)(void))
 {
 	if (handler)
 		kvm_posted_intr_wakeup_handler = handler;
 	else
 		kvm_posted_intr_wakeup_handler = dummy_handler;
 }
 EXPORT_SYMBOL_GPL(kvm_set_posted_intr_wakeup_handler);

 /*
  * Handler for POSTED_INTERRUPT_VECTOR.
  */
 __visible void smp_kvm_posted_intr_ipi(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);

 	entering_ack_irq();
 	inc_irq_stat(kvm_posted_intr_ipis);
 	exiting_irq();
 	set_irq_regs(old_regs);
 }

 /*
  * Handler for POSTED_INTERRUPT_WAKEUP_VECTOR.
  */
 __visible void smp_kvm_posted_intr_wakeup_ipi(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);

 	entering_ack_irq();
 	inc_irq_stat(kvm_posted_intr_wakeup_ipis);
 	kvm_posted_intr_wakeup_handler();
 	exiting_irq();
 	set_irq_regs(old_regs);
 }
 #endif

 __visible void __irq_entry smp_trace_x86_platform_ipi(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);

 	entering_ack_irq();
 	trace_x86_platform_ipi_entry(X86_PLATFORM_IPI_VECTOR);
 	__smp_x86_platform_ipi();
 	trace_x86_platform_ipi_exit(X86_PLATFORM_IPI_VECTOR);
 	exiting_irq();
 	set_irq_regs(old_regs);
 }

 EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);

 #ifdef CONFIG_HOTPLUG_CPU

 /* These two declarations are only used in check_irq_vectors_for_cpu_disable()
  * below, which is protected by stop_machine().  Putting them on the stack
  * results in a stack frame overflow.  Dynamically allocating could result in a
  * failure so declare these two cpumasks as global.
  */
 static struct cpumask affinity_new, online_new;

 /*
  * This cpu is going to be removed and its vectors migrated to the remaining
  * online cpus.  Check to see if there are enough vectors in the remaining cpus.
  * This function is protected by stop_machine().
  */
 int check_irq_vectors_for_cpu_disable(void)
 {
 	unsigned int this_cpu, vector, this_count, count;
 	struct irq_desc *desc;
 	struct irq_data *data;
 	int cpu;

 	this_cpu = smp_processor_id();
 	cpumask_copy(&online_new, cpu_online_mask);
 	cpumask_clear_cpu(this_cpu, &online_new);

 	this_count = 0;
 	for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
 		desc = __this_cpu_read(vector_irq[vector]);
 		if (IS_ERR_OR_NULL(desc))
 			continue;
 		/*
 		 * Protect against concurrent action removal, affinity
 		 * changes etc.
 		 */
 		raw_spin_lock(&desc->lock);
 		data = irq_desc_get_irq_data(desc);
 		cpumask_copy(&affinity_new,
 			     irq_data_get_affinity_mask(data));
 		cpumask_clear_cpu(this_cpu, &affinity_new);

 		/* Do not count inactive or per-cpu irqs. */
 		if (!irq_desc_has_action(desc) || irqd_is_per_cpu(data)) {
 			raw_spin_unlock(&desc->lock);
 			continue;
 		}

 		raw_spin_unlock(&desc->lock);
 		/*
 		 * A single irq may be mapped to multiple cpu's
 		 * vector_irq[] (for example IOAPIC cluster mode).  In
 		 * this case we have two possibilities:
 		 *
 		 * 1) the resulting affinity mask is empty; that is
 		 * this the down'd cpu is the last cpu in the irq's
 		 * affinity mask, or
 		 *
 		 * 2) the resulting affinity mask is no longer a
 		 * subset of the online cpus but the affinity mask is
 		 * not zero; that is the down'd cpu is the last online
 		 * cpu in a user set affinity mask.
 		 */
 		if (cpumask_empty(&affinity_new) ||
 		    !cpumask_subset(&affinity_new, &online_new))
 			this_count++;
 	}
 	/* No need to check any further. */
 	if (!this_count)
 		return 0;

 	count = 0;
 	for_each_online_cpu(cpu) {
 		if (cpu == this_cpu)
 			continue;
 		/*
 		 * We scan from FIRST_EXTERNAL_VECTOR to first system
 		 * vector. If the vector is marked in the used vectors
 		 * bitmap or an irq is assigned to it, we don't count
 		 * it as available.
 		 *
 		 * As this is an inaccurate snapshot anyway, we can do
 		 * this w/o holding vector_lock.
 		 */
 		for (vector = FIRST_EXTERNAL_VECTOR;
 		     vector < first_system_vector; vector++) {
 			if (!test_bit(vector, used_vectors) &&
 			    IS_ERR_OR_NULL(per_cpu(vector_irq, cpu)[vector])) {
 				if (++count == this_count)
 					return 0;
 			}
 		}
 	}

 	if (count < this_count) {
 		pr_warn("CPU %d disable failed: CPU has %u vectors assigned and there are only %u available.\n",
 			this_cpu, this_count, count);
 		return -ERANGE;
 	}
 	return 0;
 }

 /* A cpu has been removed from cpu_online_mask.  Reset irq affinities. */
 void fixup_irqs(void)
 {
 	unsigned int irq, vector;
 	static int warned;
 	struct irq_desc *desc;
 	struct irq_data *data;
 	struct irq_chip *chip;
 	int ret;

 	for_each_irq_desc(irq, desc) {
 		int break_affinity = 0;
 		int set_affinity = 1;
 		const struct cpumask *affinity;

 		if (!desc)
 			continue;
 		if (irq == 2)
 			continue;

 		/* interrupt's are disabled at this point */
 		raw_spin_lock(&desc->lock);

 		data = irq_desc_get_irq_data(desc);
 		affinity = irq_data_get_affinity_mask(data);
 		if (!irq_has_action(irq) || irqd_is_per_cpu(data) ||
 		    cpumask_subset(affinity, cpu_online_mask)) {
 			raw_spin_unlock(&desc->lock);
 			continue;
 		}

 		/*
 		 * Complete the irq move. This cpu is going down and for
 		 * non intr-remapping case, we can't wait till this interrupt
 		 * arrives at this cpu before completing the irq move.
 		 */
 		irq_force_complete_move(desc);

 		if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
 			break_affinity = 1;
 			affinity = cpu_online_mask;
 		}

 		chip = irq_data_get_irq_chip(data);
 		/*
 		 * The interrupt descriptor might have been cleaned up
 		 * already, but it is not yet removed from the radix tree
 		 */
 		if (!chip) {
 			raw_spin_unlock(&desc->lock);
 			continue;
 		}

 		if (!irqd_can_move_in_process_context(data) && chip->irq_mask)
 			chip->irq_mask(data);

 		if (chip->irq_set_affinity) {
 			ret = chip->irq_set_affinity(data, affinity, true);
 			if (ret == -ENOSPC)
 				pr_crit("IRQ %d set affinity failed because there are no available vectors.  The device assigned to this IRQ is unstable.\n", irq);
 		} else {
 			if (!(warned++))
 				set_affinity = 0;
 		}

 		/*
 		 * We unmask if the irq was not marked masked by the
 		 * core code. That respects the lazy irq disable
 		 * behaviour.
 		 */
 		if (!irqd_can_move_in_process_context(data) &&
 		    !irqd_irq_masked(data) && chip->irq_unmask)
 			chip->irq_unmask(data);

 		raw_spin_unlock(&desc->lock);

 		if (break_affinity && set_affinity)
 			pr_notice("Broke affinity for irq %i\n", irq);
 		else if (!set_affinity)
 			pr_notice("Cannot set affinity for irq %i\n", irq);
 	}

 	/*
 	 * We can remove mdelay() and then send spuriuous interrupts to
 	 * new cpu targets for all the irqs that were handled previously by
 	 * this cpu. While it works, I have seen spurious interrupt messages
 	 * (nothing wrong but still...).
 	 *
 	 * So for now, retain mdelay(1) and check the IRR and then send those
 	 * interrupts to new targets as this cpu is already offlined...
 	 */
 	mdelay(1);

 	/*
 	 * We can walk the vector array of this cpu without holding
 	 * vector_lock because the cpu is already marked !online, so
 	 * nothing else will touch it.
 	 */
 	for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
 		unsigned int irr;

 		if (IS_ERR_OR_NULL(__this_cpu_read(vector_irq[vector])))
 			continue;

 		irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
 		if (irr  & (1 << (vector % 32))) {
 			desc = __this_cpu_read(vector_irq[vector]);

 			raw_spin_lock(&desc->lock);
 			data = irq_desc_get_irq_data(desc);
 			chip = irq_data_get_irq_chip(data);
 			if (chip->irq_retrigger) {
 				chip->irq_retrigger(data);
 				__this_cpu_write(vector_irq[vector], VECTOR_RETRIGGERED);
 			}
 			raw_spin_unlock(&desc->lock);
 		}
 		if (__this_cpu_read(vector_irq[vector]) != VECTOR_RETRIGGERED)
 			__this_cpu_write(vector_irq[vector], VECTOR_UNUSED);
 	}
 }
 #endif
	/*
	* Common interrupt code for 32 and 64 bit
	*/
	#include <linux/cpu.h>
	#include <linux/interrupt.h>
	#include <linux/kernel_stat.h>
	#include <linux/of.h>
	#include <linux/seq_file.h>
	#include <linux/smp.h>
	#include <linux/ftrace.h>
	#include <linux/delay.h>
	#include <linux/export.h>

	#include <asm/apic.h>
	#include <asm/io_apic.h>
	#include <asm/irq.h>
	#include <asm/mce.h>
	#include <asm/hw_irq.h>
	#include <asm/desc.h>

	#define CREATE_TRACE_POINTS
	#include <asm/trace/irq_vectors.h>

	DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
	EXPORT_PER_CPU_SYMBOL(irq_stat);

	DEFINE_PER_CPU(struct pt_regs *, irq_regs);
	EXPORT_PER_CPU_SYMBOL(irq_regs);

	atomic_t irq_err_count;

	/* Function pointer for generic interrupt vector handling */
	void (*x86_platform_ipi_callback)(void) = NULL;

	/*
	* 'what should we do if we get a hw irq event on an illegal vector'.
	* each architecture has to answer this themselves.
	*/
	void ack_bad_irq(unsigned int irq)
	{
	if (printk_ratelimit())
	pr_err("unexpected IRQ trap at vector %02x\n", irq);

	/*
	* Currently unexpected vectors happen only on SMP and APIC.
	* We _must_ ack these because every local APIC has only N
	* irq slots per priority level, and a 'hanging, unacked' IRQ
	* holds up an irq slot - in excessive cases (when multiple
	* unexpected vectors occur) that might lock up the APIC
	* completely.
	* But only ack when the APIC is enabled -AK
	*/
	ack_APIC_irq();
	}

	#define irq_stats(x) (&per_cpu(irq_stat, x))
	/*
	* /proc/interrupts printing for arch specific interrupts
	*/
	int arch_show_interrupts(struct seq_file *p, int prec)
	{
	int j;

	seq_printf(p, "%*s: ", prec, "NMI");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->__nmi_count);
	seq_puts(p, " Non-maskable interrupts\n");
	#ifdef CONFIG_X86_LOCAL_APIC
	seq_printf(p, "%*s: ", prec, "LOC");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->apic_timer_irqs);
	seq_puts(p, " Local timer interrupts\n");

	seq_printf(p, "%*s: ", prec, "SPU");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->irq_spurious_count);
	seq_puts(p, " Spurious interrupts\n");
	seq_printf(p, "%*s: ", prec, "PMI");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->apic_perf_irqs);
	seq_puts(p, " Performance monitoring interrupts\n");
	seq_printf(p, "%*s: ", prec, "IWI");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->apic_irq_work_irqs);
	seq_puts(p, " IRQ work interrupts\n");
	seq_printf(p, "%*s: ", prec, "RTR");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->icr_read_retry_count);
	seq_puts(p, " APIC ICR read retries\n");
	#endif
	if (x86_platform_ipi_callback) {
	seq_printf(p, "%*s: ", prec, "PLT");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->x86_platform_ipis);
	seq_puts(p, " Platform interrupts\n");
	}
	#ifdef CONFIG_SMP
	seq_printf(p, "%*s: ", prec, "RES");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
	seq_puts(p, " Rescheduling interrupts\n");
	seq_printf(p, "%*s: ", prec, "CAL");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->irq_call_count);
	seq_puts(p, " Function call interrupts\n");
	seq_printf(p, "%*s: ", prec, "TLB");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
	seq_puts(p, " TLB shootdowns\n");
	#endif
	#ifdef CONFIG_X86_THERMAL_VECTOR
	seq_printf(p, "%*s: ", prec, "TRM");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->irq_thermal_count);
	seq_puts(p, " Thermal event interrupts\n");
	#endif
	#ifdef CONFIG_X86_MCE_THRESHOLD
	seq_printf(p, "%*s: ", prec, "THR");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->irq_threshold_count);
	seq_puts(p, " Threshold APIC interrupts\n");
	#endif
	#ifdef CONFIG_X86_MCE_AMD
	seq_printf(p, "%*s: ", prec, "DFR");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->irq_deferred_error_count);
	seq_puts(p, " Deferred Error APIC interrupts\n");
	#endif
	#ifdef CONFIG_X86_MCE
	seq_printf(p, "%*s: ", prec, "MCE");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", per_cpu(mce_exception_count, j));
	seq_puts(p, " Machine check exceptions\n");
	seq_printf(p, "%*s: ", prec, "MCP");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", per_cpu(mce_poll_count, j));
	seq_puts(p, " Machine check polls\n");
	#endif
	#if IS_ENABLED(CONFIG_HYPERV) \|\| defined(CONFIG_XEN)
	if (test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors)) {
	seq_printf(p, "%*s: ", prec, "HYP");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ",
	irq_stats(j)->irq_hv_callback_count);
	seq_puts(p, " Hypervisor callback interrupts\n");
	}
	#endif
	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
	#if defined(CONFIG_X86_IO_APIC)
	seq_printf(p, "%*s: %10u\n", prec, "MIS", atomic_read(&irq_mis_count));
	#endif
	#ifdef CONFIG_HAVE_KVM
	seq_printf(p, "%*s: ", prec, "PIN");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ", irq_stats(j)->kvm_posted_intr_ipis);
	seq_puts(p, " Posted-interrupt notification event\n");

	seq_printf(p, "%*s: ", prec, "PIW");
	for_each_online_cpu(j)
	seq_printf(p, "%10u ",
	irq_stats(j)->kvm_posted_intr_wakeup_ipis);
	seq_puts(p, " Posted-interrupt wakeup event\n");
	#endif
	return 0;
	}

	/*
	* /proc/stat helpers
	*/
	u64 arch_irq_stat_cpu(unsigned int cpu)
	{
	u64 sum = irq_stats(cpu)->__nmi_count;

	#ifdef CONFIG_X86_LOCAL_APIC
	sum += irq_stats(cpu)->apic_timer_irqs;
	sum += irq_stats(cpu)->irq_spurious_count;
	sum += irq_stats(cpu)->apic_perf_irqs;
	sum += irq_stats(cpu)->apic_irq_work_irqs;
	sum += irq_stats(cpu)->icr_read_retry_count;
	#endif
	if (x86_platform_ipi_callback)
	sum += irq_stats(cpu)->x86_platform_ipis;
	#ifdef CONFIG_SMP
	sum += irq_stats(cpu)->irq_resched_count;
	sum += irq_stats(cpu)->irq_call_count;
	#endif
	#ifdef CONFIG_X86_THERMAL_VECTOR
	sum += irq_stats(cpu)->irq_thermal_count;
	#endif
	#ifdef CONFIG_X86_MCE_THRESHOLD
	sum += irq_stats(cpu)->irq_threshold_count;
	#endif
	#ifdef CONFIG_X86_MCE
	sum += per_cpu(mce_exception_count, cpu);
	sum += per_cpu(mce_poll_count, cpu);
	#endif
	return sum;
	}

	u64 arch_irq_stat(void)
	{
	u64 sum = atomic_read(&irq_err_count);
	return sum;
	}


	/*
	* do_IRQ handles all normal device IRQ's (the special
	* SMP cross-CPU interrupts have their own specific
	* handlers).
	*/
	__visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
	{
	struct pt_regs *old_regs = set_irq_regs(regs);
	struct irq_desc * desc;
	/* high bit used in ret_from_ code */
	unsigned vector = ~regs->orig_ax;

	/*
	* NB: Unlike exception entries, IRQ entries do not reliably
	* handle context tracking in the low-level entry code. This is
	* because syscall entries execute briefly with IRQs on before
	* updating context tracking state, so we can take an IRQ from
	* kernel mode with CONTEXT_USER. The low-level entry code only
	* updates the context if we came from user mode, so we won't
	* switch to CONTEXT_KERNEL. We'll fix that once the syscall
	* code is cleaned up enough that we can cleanly defer enabling
	* IRQs.
	*/

	entering_irq();

	/* entering_irq() tells RCU that we're not quiescent. Check it. */
	RCU_LOCKDEP_WARN(!rcu_is_watching(), "IRQ failed to wake up RCU");

	desc = __this_cpu_read(vector_irq[vector]);

	if (!handle_irq(desc, regs)) {
	ack_APIC_irq();

	if (desc != VECTOR_RETRIGGERED) {
	pr_emerg_ratelimited("%s: %d.%d No irq handler for vector\n",
	__func__, smp_processor_id(),
	vector);
	} else {
	__this_cpu_write(vector_irq[vector], VECTOR_UNUSED);
	}
	}

	exiting_irq();

	set_irq_regs(old_regs);
	return 1;
	}

	/*
	* Handler for X86_PLATFORM_IPI_VECTOR.
	*/
	void __smp_x86_platform_ipi(void)
	{
	inc_irq_stat(x86_platform_ipis);

	if (x86_platform_ipi_callback)
	x86_platform_ipi_callback();
	}

	__visible void __irq_entry smp_x86_platform_ipi(struct pt_regs *regs)
	{
	struct pt_regs *old_regs = set_irq_regs(regs);

	entering_ack_irq();
	__smp_x86_platform_ipi();
	exiting_irq();
	set_irq_regs(old_regs);
	}

	#ifdef CONFIG_HAVE_KVM
	static void dummy_handler(void) {}
	static void (*kvm_posted_intr_wakeup_handler)(void) = dummy_handler;

	void kvm_set_posted_intr_wakeup_handler(void (*handler)(void))
	{
	if (handler)
	kvm_posted_intr_wakeup_handler = handler;
	else
	kvm_posted_intr_wakeup_handler = dummy_handler;
	}
	EXPORT_SYMBOL_GPL(kvm_set_posted_intr_wakeup_handler);

	/*
	* Handler for POSTED_INTERRUPT_VECTOR.
	*/
	__visible void smp_kvm_posted_intr_ipi(struct pt_regs *regs)
	{
	struct pt_regs *old_regs = set_irq_regs(regs);

	entering_ack_irq();
	inc_irq_stat(kvm_posted_intr_ipis);
	exiting_irq();
	set_irq_regs(old_regs);
	}

	/*
	* Handler for POSTED_INTERRUPT_WAKEUP_VECTOR.
	*/
	__visible void smp_kvm_posted_intr_wakeup_ipi(struct pt_regs *regs)
	{
	struct pt_regs *old_regs = set_irq_regs(regs);

	entering_ack_irq();
	inc_irq_stat(kvm_posted_intr_wakeup_ipis);
	kvm_posted_intr_wakeup_handler();
	exiting_irq();
	set_irq_regs(old_regs);
	}
	#endif

	__visible void __irq_entry smp_trace_x86_platform_ipi(struct pt_regs *regs)
	{
	struct pt_regs *old_regs = set_irq_regs(regs);

	entering_ack_irq();
	trace_x86_platform_ipi_entry(X86_PLATFORM_IPI_VECTOR);
	__smp_x86_platform_ipi();
	trace_x86_platform_ipi_exit(X86_PLATFORM_IPI_VECTOR);
	exiting_irq();
	set_irq_regs(old_regs);
	}

	EXPORT_SYMBOL_GPL(vector_used_by_percpu_irq);

	#ifdef CONFIG_HOTPLUG_CPU

	/* These two declarations are only used in check_irq_vectors_for_cpu_disable()
	* below, which is protected by stop_machine(). Putting them on the stack
	* results in a stack frame overflow. Dynamically allocating could result in a
	* failure so declare these two cpumasks as global.
	*/
	static struct cpumask affinity_new, online_new;

	/*
	* This cpu is going to be removed and its vectors migrated to the remaining
	* online cpus. Check to see if there are enough vectors in the remaining cpus.
	* This function is protected by stop_machine().
	*/
	int check_irq_vectors_for_cpu_disable(void)
	{
	unsigned int this_cpu, vector, this_count, count;
	struct irq_desc *desc;
	struct irq_data *data;
	int cpu;

	this_cpu = smp_processor_id();
	cpumask_copy(&online_new, cpu_online_mask);
	cpumask_clear_cpu(this_cpu, &online_new);

	this_count = 0;
	for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
	desc = __this_cpu_read(vector_irq[vector]);
	if (IS_ERR_OR_NULL(desc))
	continue;
	/*
	* Protect against concurrent action removal, affinity
	* changes etc.
	*/
	raw_spin_lock(&desc->lock);
	data = irq_desc_get_irq_data(desc);
	cpumask_copy(&affinity_new,
	irq_data_get_affinity_mask(data));
	cpumask_clear_cpu(this_cpu, &affinity_new);

	/* Do not count inactive or per-cpu irqs. */
	if (!irq_desc_has_action(desc) \|\| irqd_is_per_cpu(data)) {
	raw_spin_unlock(&desc->lock);
	continue;
	}

	raw_spin_unlock(&desc->lock);
	/*
	* A single irq may be mapped to multiple cpu's
	* vector_irq[] (for example IOAPIC cluster mode). In
	* this case we have two possibilities:
	*
	* 1) the resulting affinity mask is empty; that is
	* this the down'd cpu is the last cpu in the irq's
	* affinity mask, or
	*
	* 2) the resulting affinity mask is no longer a
	* subset of the online cpus but the affinity mask is
	* not zero; that is the down'd cpu is the last online
	* cpu in a user set affinity mask.
	*/
	if (cpumask_empty(&affinity_new) \|\|
	!cpumask_subset(&affinity_new, &online_new))
	this_count++;
	}
	/* No need to check any further. */
	if (!this_count)
	return 0;

	count = 0;
	for_each_online_cpu(cpu) {
	if (cpu == this_cpu)
	continue;
	/*
	* We scan from FIRST_EXTERNAL_VECTOR to first system
	* vector. If the vector is marked in the used vectors
	* bitmap or an irq is assigned to it, we don't count
	* it as available.
	*
	* As this is an inaccurate snapshot anyway, we can do
	* this w/o holding vector_lock.
	*/
	for (vector = FIRST_EXTERNAL_VECTOR;
	vector < first_system_vector; vector++) {
	if (!test_bit(vector, used_vectors) &&
	IS_ERR_OR_NULL(per_cpu(vector_irq, cpu)[vector])) {
	if (++count == this_count)
	return 0;
	}
	}
	}

	if (count < this_count) {
	pr_warn("CPU %d disable failed: CPU has %u vectors assigned and there are only %u available.\n",
	this_cpu, this_count, count);
	return -ERANGE;
	}
	return 0;
	}

	/* A cpu has been removed from cpu_online_mask. Reset irq affinities. */
	void fixup_irqs(void)
	{
	unsigned int irq, vector;
	static int warned;
	struct irq_desc *desc;
	struct irq_data *data;
	struct irq_chip *chip;
	int ret;

	for_each_irq_desc(irq, desc) {
	int break_affinity = 0;
	int set_affinity = 1;
	const struct cpumask *affinity;

	if (!desc)
	continue;
	if (irq == 2)
	continue;

	/* interrupt's are disabled at this point */
	raw_spin_lock(&desc->lock);

	data = irq_desc_get_irq_data(desc);
	affinity = irq_data_get_affinity_mask(data);
	if (!irq_has_action(irq) \|\| irqd_is_per_cpu(data) \|\|
	cpumask_subset(affinity, cpu_online_mask)) {
	raw_spin_unlock(&desc->lock);
	continue;
	}

	/*
	* Complete the irq move. This cpu is going down and for
	* non intr-remapping case, we can't wait till this interrupt
	* arrives at this cpu before completing the irq move.
	*/
	irq_force_complete_move(desc);

	if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
	break_affinity = 1;
	affinity = cpu_online_mask;
	}

	chip = irq_data_get_irq_chip(data);
	/*
	* The interrupt descriptor might have been cleaned up
	* already, but it is not yet removed from the radix tree
	*/
	if (!chip) {
	raw_spin_unlock(&desc->lock);
	continue;
	}

	if (!irqd_can_move_in_process_context(data) && chip->irq_mask)
	chip->irq_mask(data);

	if (chip->irq_set_affinity) {
	ret = chip->irq_set_affinity(data, affinity, true);
	if (ret == -ENOSPC)
	pr_crit("IRQ %d set affinity failed because there are no available vectors. The device assigned to this IRQ is unstable.\n", irq);
	} else {
	if (!(warned++))
	set_affinity = 0;
	}

	/*
	* We unmask if the irq was not marked masked by the
	* core code. That respects the lazy irq disable
	* behaviour.
	*/
	if (!irqd_can_move_in_process_context(data) &&
	!irqd_irq_masked(data) && chip->irq_unmask)
	chip->irq_unmask(data);

	raw_spin_unlock(&desc->lock);

	if (break_affinity && set_affinity)
	pr_notice("Broke affinity for irq %i\n", irq);
	else if (!set_affinity)
	pr_notice("Cannot set affinity for irq %i\n", irq);
	}

	/*
	* We can remove mdelay() and then send spuriuous interrupts to
	* new cpu targets for all the irqs that were handled previously by
	* this cpu. While it works, I have seen spurious interrupt messages
	* (nothing wrong but still...).
	*
	* So for now, retain mdelay(1) and check the IRR and then send those
	* interrupts to new targets as this cpu is already offlined...
	*/
	mdelay(1);

	/*
	* We can walk the vector array of this cpu without holding
	* vector_lock because the cpu is already marked !online, so
	* nothing else will touch it.
	*/
	for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
	unsigned int irr;

	if (IS_ERR_OR_NULL(__this_cpu_read(vector_irq[vector])))
	continue;

	irr = apic_read(APIC_IRR + (vector / 32 * 0x10));
	if (irr & (1 << (vector % 32))) {
	desc = __this_cpu_read(vector_irq[vector]);

	raw_spin_lock(&desc->lock);
	data = irq_desc_get_irq_data(desc);
	chip = irq_data_get_irq_chip(data);
	if (chip->irq_retrigger) {
	chip->irq_retrigger(data);
	__this_cpu_write(vector_irq[vector], VECTOR_RETRIGGERED);
	}
	raw_spin_unlock(&desc->lock);
	}
	if (__this_cpu_read(vector_irq[vector]) != VECTOR_RETRIGGERED)
	__this_cpu_write(vector_irq[vector], VECTOR_UNUSED);
	}
	}
	#endif