genirq: Add protection against unsafe usage of generic_handle_irq()

In general calling generic_handle_irq() with interrupts disabled from non
interrupt context is harmless. For some interrupt controllers like the x86
trainwrecks this is outright dangerous as it might corrupt state if an
interrupt affinity change is pending.

Add infrastructure which allows to mark interrupts as unsafe and catch such
usage in generic_handle_irq().

Reported-by: sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lkml.kernel.org/r/20200306130623.590923677@linutronix.de

1 files changed, 8 insertions, 0 deletions

diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index c9d8eb7f5c02..5be382fc9415 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -425,6 +425,10 @@ static inline struct cpumask *irq_desc_get_pending_mask(struct irq_desc *desc)
 {
 	return desc->pending_mask;
 }
+static inline bool handle_enforce_irqctx(struct irq_data *data)
+{
+	return irqd_is_handle_enforce_irqctx(data);
+}
 bool irq_fixup_move_pending(struct irq_desc *desc, bool force_clear);
 #else /* CONFIG_GENERIC_PENDING_IRQ */
 static inline bool irq_can_move_pcntxt(struct irq_data *data)
@@ -451,6 +455,10 @@ static inline bool irq_fixup_move_pending(struct irq_desc *desc, bool fclear)
 {
 	return false;
 }
+static inline bool handle_enforce_irqctx(struct irq_data *data)
+{
+	return false;
+}
 #endif /* !CONFIG_GENERIC_PENDING_IRQ */
 
 #if !defined(CONFIG_IRQ_DOMAIN) || !defined(CONFIG_IRQ_DOMAIN_HIERARCHY)