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Commit b3ec0a37 authored by Suresh Siddha's avatar Suresh Siddha Committed by Ingo Molnar
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x86: Use EOI register in io-apic on intel platforms 



IO-APIC's in intel chipsets support EOI register starting from
IO-APIC version 2. Use that when ever we need to clear the
IO-APIC RTE's RemoteIRR bit explicitly.

Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Acked-by: default avatarGary Hade <garyhade@us.ibm.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <20091026230001.947855317@sbs-t61.sc.intel.com>
[ Marked use_eio_reg as __read_mostly, fixed small details ]
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a5e74b84

arch/x86/kernel/apic/io_apic.c

+54 −27
Original line number Diff line number Diff line
@@ -2492,6 +2492,51 @@ static void ack_apic_edge(unsigned int irq) 


atomic_t irq_mis_count;



static int use_eoi_reg __read_mostly;



static void __eoi_ioapic_irq(unsigned int irq, struct irq_cfg *cfg)

{

	struct irq_pin_list *entry;



	for_each_irq_pin(entry, cfg->irq_2_pin) {

		if (irq_remapped(irq))

			io_apic_eoi(entry->apic, entry->pin);

		else

			io_apic_eoi(entry->apic, cfg->vector);

	}

}



static void eoi_ioapic_irq(struct irq_desc *desc)

{

	struct irq_cfg *cfg;

	unsigned long flags;

	unsigned int irq;



	irq = desc->irq;

	cfg = desc->chip_data;



	spin_lock_irqsave(&ioapic_lock, flags);

	__eoi_ioapic_irq(irq, cfg);

	spin_unlock_irqrestore(&ioapic_lock, flags);

}



static int ioapic_supports_eoi(void)

{

	struct pci_dev *root;



	root = pci_get_bus_and_slot(0, PCI_DEVFN(0, 0));

	if (root && root->vendor == PCI_VENDOR_ID_INTEL &&

	    mp_ioapics[0].apicver >= 0x2) {

		use_eoi_reg = 1;

		printk(KERN_INFO "IO-APIC supports EOI register\n");

	} else

		printk(KERN_INFO "IO-APIC doesn't support EOI\n");



	return 0;

}



fs_initcall(ioapic_supports_eoi);



static void ack_apic_level(unsigned int irq)

{

	struct irq_desc *desc = irq_to_desc(irq);
@@ -2575,37 +2620,19 @@ static void ack_apic_level(unsigned int irq) 
	/* Tail end of version 0x11 I/O APIC bug workaround */

	if (!(v & (1 << (i & 0x1f)))) {

		atomic_inc(&irq_mis_count);



		if (use_eoi_reg)

			eoi_ioapic_irq(desc);

		else {

			spin_lock(&ioapic_lock);

			__mask_and_edge_IO_APIC_irq(cfg);

			__unmask_and_level_IO_APIC_irq(cfg);

			spin_unlock(&ioapic_lock);

		}

	}



#ifdef CONFIG_INTR_REMAP

static void __eoi_ioapic_irq(unsigned int irq, struct irq_cfg *cfg)

{

	struct irq_pin_list *entry;



	for_each_irq_pin(entry, cfg->irq_2_pin)

		io_apic_eoi(entry->apic, entry->pin);

}



static void

eoi_ioapic_irq(struct irq_desc *desc)

{

	struct irq_cfg *cfg;

	unsigned long flags;

	unsigned int irq;



	irq = desc->irq;

	cfg = desc->chip_data;



	spin_lock_irqsave(&ioapic_lock, flags);

	__eoi_ioapic_irq(irq, cfg);

	spin_unlock_irqrestore(&ioapic_lock, flags);

}



#ifdef CONFIG_INTR_REMAP

static void ir_ack_apic_edge(unsigned int irq)

{

	ack_APIC_irq();