From b3ec0a37a7907813bb4fb85a2d94102c152470b7 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Mon, 26 Oct 2009 14:24:35 -0800 Subject: [PATCH] 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: Suresh Siddha Acked-by: Gary Hade Cc: Eric W. Biederman LKML-Reference: <20091026230001.947855317@sbs-t61.sc.intel.com> [ Marked use_eio_reg as __read_mostly, fixed small details ] Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/io_apic.c | 81 ++++++++++++++++++++++------------ 1 file changed, 54 insertions(+), 27 deletions(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 4e886efd9a15..31e9db3c12ad 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -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); - spin_lock(&ioapic_lock); - __mask_and_edge_IO_APIC_irq(cfg); - __unmask_and_level_IO_APIC_irq(cfg); - spin_unlock(&ioapic_lock); + + 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); -} - static void ir_ack_apic_edge(unsigned int irq) { ack_APIC_irq(); -- 2.30.2