Second try at this ....
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=64831 When downing a cpu it is possible that there are unhandled irqs left in the APIC IRR register. fixup_irqs() goes through the IRR and retriggers the IRQs left in the APIC IRR. After this, the vector for the irq is set to -1. There is a possibility here, however, that the CPU does handle an irq in the IRR and then calls the vector. When this happens, do_IRQ() spits out a warning like kernel: [ 612.014573] do_IRQ: 56.134 No irq handler for vector (irq -1) I added a debug printk to output which CPU & vector was retriggered and discovered that that we are getting bogus events. This patchset resolves this by adding definitions for VECTOR_UNDEFINED(-1) and VECTOR_RETRIGGERED(-2) and modifying the code to use them. Signed-off-by: Prarit Bhargava <pra...@redhat.com> Cc: x...@kernel.org --- arch/x86/include/asm/hw_irq.h | 2 ++ arch/x86/kernel/apic/io_apic.c | 13 +++++++------ arch/x86/kernel/irq.c | 17 +++++++++++------ arch/x86/kernel/irqinit.c | 4 ++-- 4 files changed, 22 insertions(+), 14 deletions(-) diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h index 92b3bae..22c425e 100644 --- a/arch/x86/include/asm/hw_irq.h +++ b/arch/x86/include/asm/hw_irq.h @@ -188,6 +188,8 @@ extern __visible void smp_invalidate_interrupt(struct pt_regs *); extern void (*__initconst interrupt[NR_VECTORS-FIRST_EXTERNAL_VECTOR])(void); +#define VECTOR_UNDEFINED -1 +#define VECTOR_RETRIGGERED -2 typedef int vector_irq_t[NR_VECTORS]; DECLARE_PER_CPU(vector_irq_t, vector_irq); extern void setup_vector_irq(int cpu); diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index e63a5bd..6e1541c 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1143,7 +1143,8 @@ next: goto next; for_each_cpu_and(new_cpu, tmp_mask, cpu_online_mask) - if (per_cpu(vector_irq, new_cpu)[vector] != -1) + if (per_cpu(vector_irq, new_cpu)[vector] > + VECTOR_UNDEFINED) goto next; /* Found one! */ current_vector = vector; @@ -1183,7 +1184,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg) vector = cfg->vector; for_each_cpu_and(cpu, cfg->domain, cpu_online_mask) - per_cpu(vector_irq, cpu)[vector] = -1; + per_cpu(vector_irq, cpu)[vector] = VECTOR_UNDEFINED; cfg->vector = 0; cpumask_clear(cfg->domain); @@ -1195,7 +1196,7 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg) vector++) { if (per_cpu(vector_irq, cpu)[vector] != irq) continue; - per_cpu(vector_irq, cpu)[vector] = -1; + per_cpu(vector_irq, cpu)[vector] = VECTOR_UNDEFINED; break; } } @@ -1228,12 +1229,12 @@ void __setup_vector_irq(int cpu) /* Mark the free vectors */ for (vector = 0; vector < NR_VECTORS; ++vector) { irq = per_cpu(vector_irq, cpu)[vector]; - if (irq < 0) + if (irq <= VECTOR_UNDEFINED) continue; cfg = irq_cfg(irq); if (!cpumask_test_cpu(cpu, cfg->domain)) - per_cpu(vector_irq, cpu)[vector] = -1; + per_cpu(vector_irq, cpu)[vector] = VECTOR_UNDEFINED; } raw_spin_unlock(&vector_lock); } @@ -2208,7 +2209,7 @@ asmlinkage void smp_irq_move_cleanup_interrupt(void) struct irq_cfg *cfg; irq = __this_cpu_read(vector_irq[vector]); - if (irq == -1) + if (irq <= VECTOR_UNDEFINED) continue; desc = irq_to_desc(irq); diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 22d0687..030f0e2 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -193,9 +193,10 @@ __visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs) if (!handle_irq(irq, regs)) { ack_APIC_irq(); - if (printk_ratelimit()) - pr_emerg("%s: %d.%d No irq handler for vector (irq %d)\n", - __func__, smp_processor_id(), vector, irq); + if (irq != VECTOR_RETRIGGERED) + pr_emerg_ratelimited("%s: %d.%d No irq handler for vector (irq %d)\n", + __func__, smp_processor_id(), + vector, irq); } irq_exit(); @@ -344,7 +345,7 @@ void fixup_irqs(void) for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) { unsigned int irr; - if (__this_cpu_read(vector_irq[vector]) < 0) + if (__this_cpu_read(vector_irq[vector]) <= VECTOR_UNDEFINED) continue; irr = apic_read(APIC_IRR + (vector / 32 * 0x10)); @@ -355,11 +356,15 @@ void fixup_irqs(void) data = irq_desc_get_irq_data(desc); chip = irq_data_get_irq_chip(data); raw_spin_lock(&desc->lock); - if (chip->irq_retrigger) + if (chip->irq_retrigger) { chip->irq_retrigger(data); + __this_cpu_write(vector_irq[vector], + VECTOR_RETRIGGERED); + } raw_spin_unlock(&desc->lock); } - __this_cpu_write(vector_irq[vector], -1); + if (__this_cpu_read(vector_irq[vector]) != VECTOR_RETRIGGERED) + __this_cpu_write(vector_irq[vector], VECTOR_UNDEFINED); } } #endif diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c index a2a1fbc..7f50156 100644 --- a/arch/x86/kernel/irqinit.c +++ b/arch/x86/kernel/irqinit.c @@ -52,7 +52,7 @@ static struct irqaction irq2 = { }; DEFINE_PER_CPU(vector_irq_t, vector_irq) = { - [0 ... NR_VECTORS - 1] = -1, + [0 ... NR_VECTORS - 1] = VECTOR_UNDEFINED, }; int vector_used_by_percpu_irq(unsigned int vector) @@ -60,7 +60,7 @@ int vector_used_by_percpu_irq(unsigned int vector) int cpu; for_each_online_cpu(cpu) { - if (per_cpu(vector_irq, cpu)[vector] != -1) + if (per_cpu(vector_irq, cpu)[vector] > VECTOR_UNDEFINED) return 1; } -- 1.7.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
