[PATCHv2 3/5] kernel/irq: make irq_{enter, exit}() in handle_domain_irq() arch optional

[Pingfan Liu]

handle_domain_irq() contains two major parts:
  -1. irq_enter()/irq_exit(), which serves as hooks for rcu and trace etc.
  -2. irq mapping and dispatching

After the introduction of irqentry_enter()/irqentry_exit() and arch
specific counterpart (e.g. arm64), roughly speaking, rcu_irq_enter() has
already been called.  Hence here comes requirement to move
irq_enter/irq_exit out of handle_domain_irq(). And arches should handle
about irq_enter_rcu()/irq_exit_rcu() by themself.

Since there is still arches, which does not adopt irqentry_enter(), let
irq_enter()/irq_exit() arch optional in handle_domain_irq().

Signed-off-by: Pingfan Liu <kernelfans at gmail.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Marc Zyngier <maz at kernel.org>
Cc: Joey Gouly <joey.gouly at arm.com>
Cc: Sami Tolvanen <samitolvanen at google.com>
Cc: Julien Thierry <julien.thierry at arm.com>
Cc: Yuichi Ito <ito-yuichi at fujitsu.com>
Cc: linux-arm-kernel at lists.infradead.org
To: linux-kernel at vger.kernel.org
---
 kernel/irq/Kconfig   | 3 +++
 kernel/irq/irqdesc.c | 4 ++++
 2 files changed, 7 insertions(+)

diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index fbc54c2a7f23..defa1db2d664 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -100,6 +100,9 @@ config IRQ_MSI_IOMMU
 config HANDLE_DOMAIN_IRQ
 	bool
 
+config HAVE_ARCH_IRQENTRY
+	bool
+
 config IRQ_TIMINGS
 	bool
 
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 4e3c29bb603c..fd5dd9d278b5 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -693,7 +693,9 @@ int handle_domain_irq(struct irq_domain *domain,
 	struct irq_desc *desc;
 	int ret = 0;
 
+#ifndef CONFIG_HAVE_ARCH_IRQENTRY
 	irq_enter();
+#endif
 
 	/* The irqdomain code provides boundary checks */
 	desc = irq_resolve_mapping(domain, hwirq);
@@ -702,7 +704,9 @@ int handle_domain_irq(struct irq_domain *domain,
 	else
 		ret = -EINVAL;
 
+#ifndef CONFIG_HAVE_ARCH_IRQENTRY
 	irq_exit();
+#endif
 	set_irq_regs(old_regs);
 	return ret;
 }
-- 
2.31.1