[PATCH AUTOSEL 5.1 208/219] genirq: Update irq stats from NMI handlers

Sasha Levin
2019-07-15T14:16:51Z

From: Shijith Thotton <sthotton@marvell.com>

[ Upstream commit c09cb1293523dd786ae54a12fd88001542cba2f6 ]

The NMI handlers handle_percpu_devid_fasteoi_nmi() and handle_fasteoi_nmi()
do not update the interrupt counts. Due to that the NMI interrupt count
does not show up correctly in /proc/interrupts.

Add the statistics and treat the NMI handlers in the same way as per cpu
interrupts and prevent them from updating irq_desc::tot_count as this might
be corrupted due to concurrency.

[ tglx: Massaged changelog ]

Fixes: 2dcf1fbcad35 ("genirq: Provide NMI handlers")
Signed-off-by: Shijith Thotton <sthotton@marvell.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1562313336-11888-1-git-send-email-sthotton@marvell.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/irq/chip.c | 4 ++++
kernel/irq/irqdesc.c | 8 +++++++-
2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 51128bea3846..9209a60d9b85 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -748,6 +748,8 @@ void handle_fasteoi_nmi(struct irq_desc *desc)
unsigned int irq = irq_desc_get_irq(desc);
irqreturn_t res;

+ __kstat_incr_irqs_this_cpu(desc);
+
trace_irq_handler_entry(irq, action);
/*
* NMIs cannot be shared, there is only one action.
@@ -962,6 +964,8 @@ void handle_percpu_devid_fasteoi_nmi(struct irq_desc *desc)
unsigned int irq = irq_desc_get_irq(desc);
irqreturn_t res;

+ __kstat_incr_irqs_this_cpu(desc);
+
trace_irq_handler_entry(irq, action);
res = action->handler(irq, raw_cpu_ptr(action->percpu_dev_id));
trace_irq_handler_exit(irq, action, res);
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 9f8a709337cf..8a93df71673d 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -945,6 +945,11 @@ unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
*per_cpu_ptr(desc->kstat_irqs, cpu) : 0;
}

+static bool irq_is_nmi(struct irq_desc *desc)
+{
+ return desc->istate & IRQS_NMI;
+}
+
/**
* kstat_irqs - Get the statistics for an interrupt
* @irq: The interrupt number
@@ -962,7 +967,8 @@ unsigned int kstat_irqs(unsigned int irq)
if (!desc || !desc->kstat_irqs)
return 0;
if (!irq_settings_is_per_cpu_devid(desc) &&
- !irq_settings_is_per_cpu(desc))
+ !irq_settings_is_per_cpu(desc) &&
+ !irq_is_nmi(desc))
return desc->tot_count;

for_each_possible_cpu(cpu)
--
2.20.1