irq: arc: avoid CONFIG_HANDLE_DOMAIN_IRQ

In preparation for removing HANDLE_DOMAIN_IRQ, have arch/arc perform all
the necessary IRQ entry accounting in its entry code.

There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineet Gupta <vgupta@kernel.org>

arch/arc/Kconfig

@@ -40,7 +40,6 @@ config ARC
 	select HAVE_KRETPROBES
 	select HAVE_MOD_ARCH_SPECIFIC
 	select HAVE_PERF_EVENTS
-	select HANDLE_DOMAIN_IRQ
 	select IRQ_DOMAIN
 	select MODULES_USE_ELF_RELA
 	select OF

arch/arc/kernel/irq.c

@@ -6,6 +6,8 @@
 #include <linux/interrupt.h>
 #include <linux/irqchip.h>
 #include <asm/mach_desc.h>
+
+#include <asm/irq_regs.h>
 #include <asm/smp.h>
 
 /*
@@ -39,5 +41,11 @@ void __init init_IRQ(void)
  */
 void arch_do_IRQ(unsigned int hwirq, struct pt_regs *regs)
 {
-	handle_domain_irq(NULL, hwirq, regs);
+	struct pt_regs *old_regs;
+
+	irq_enter();
+	old_regs = set_irq_regs(regs);
+	generic_handle_domain_irq(NULL, hwirq);
+	set_irq_regs(old_regs);
+	irq_exit();
 }