genirq: Hide irq_cpu_{on,off}line() behind a deprecated option

irq_cpu_{on,off}line() are now only used by the Octeon platform.
Make their use conditional on this plaform being enabled, and
otherwise hidden away.

Signed-off-by: Marc Zyngier <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Tested-by: Serge Semin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Marc Zyngier

include/linux/irq.h

@@ -524,9 +524,10 @@ struct irq_chip {
 	void		(*irq_bus_lock)(struct irq_data *data);
 	void		(*irq_bus_sync_unlock)(struct irq_data *data);
 
+#ifdef CONFIG_DEPRECATED_IRQ_CPU_ONOFFLINE
 	void		(*irq_cpu_online)(struct irq_data *data);
 	void		(*irq_cpu_offline)(struct irq_data *data);
-
+#endif
 	void		(*irq_suspend)(struct irq_data *data);
 	void		(*irq_resume)(struct irq_data *data);
 	void		(*irq_pm_shutdown)(struct irq_data *data);
@@ -606,8 +607,10 @@ struct irqaction;
 extern int setup_percpu_irq(unsigned int irq, struct irqaction *new);
 extern void remove_percpu_irq(unsigned int irq, struct irqaction *act);
 
+#ifdef CONFIG_DEPRECATED_IRQ_CPU_ONOFFLINE
 extern void irq_cpu_online(void);
 extern void irq_cpu_offline(void);
+#endif
 extern int irq_set_affinity_locked(struct irq_data *data,
 				   const struct cpumask *cpumask, bool force);
 extern int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info);

kernel/irq/Kconfig

@@ -144,3 +144,10 @@ config GENERIC_IRQ_MULTI_HANDLER
 	bool
 	help
 	  Allow to specify the low level IRQ handler at run time.
+
+# Cavium Octeon is the last system to use this deprecated option
+# Do not even think of enabling this on any new platform
+config DEPRECATED_IRQ_CPU_ONOFFLINE
+	bool
+	depends on CAVIUM_OCTEON_SOC
+	default CAVIUM_OCTEON_SOC

kernel/irq/chip.c

@@ -1122,6 +1122,7 @@ void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set)
 }
 EXPORT_SYMBOL_GPL(irq_modify_status);
 
+#ifdef CONFIG_DEPRECATED_IRQ_CPU_ONOFFLINE
 /**
  *	irq_cpu_online - Invoke all irq_cpu_online functions.
  *
@@ -1181,6 +1182,7 @@ void irq_cpu_offline(void)
 		raw_spin_unlock_irqrestore(&desc->lock, flags);
 	}
 }
+#endif
 
 #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY