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Date: Mon, 2 Dec 2013 08:23:58 -0500
From: Prarit Bhargava <prarit@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: Prarit Bhargava <prarit@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
Michel Lespinasse <walken@...gle.com>,
Andi Kleen <ak@...ux.intel.com>,
Seiji Aguchi <seiji.aguchi@....com>,
Yang Zhang <yang.z.zhang@...el.com>,
Paul Gortmaker <paul.gortmaker@...driver.com>,
janet.morgan@...el.com, tony.luck@...el.com
Subject: [PATCH] x86, Fix do_IRQ interrupt warning for cpu hotplug retriggered irqs
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 <prarit@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: x86@...nel.org
Cc: Michel Lespinasse <walken@...gle.com>
Cc: Andi Kleen <ak@...ux.intel.com>
Cc: Seiji Aguchi <seiji.aguchi@....com>
Cc: Yang Zhang <yang.z.zhang@...el.com>
Cc: Paul Gortmaker <paul.gortmaker@...driver.com>
Cc: janet.morgan@...el.com
Cc: tony.luck@...el.com
---
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
--
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