irq: remove handle_domain_{irq,nmi}()

Now that entry code handles IRQ entry (including setting the IRQ regs)
before calling irqchip code, irqchip code can safely call
generic_handle_domain_irq(), and there's no functional reason for it to
call handle_domain_irq().

Let's cement this split of responsibility and remove handle_domain_irq()
entirely, updating irqchip drivers to call generic_handle_domain_irq().

For consistency, handle_domain_nmi() is similarly removed and replaced
with a generic_handle_domain_nmi() function which also does not perform
any entry logic.

Previously handle_domain_{irq,nmi}() had a WARN_ON() which would fire
when they were called in an inappropriate context. So that we can
identify similar issues going forward, similar WARN_ON_ONCE() logic is
added to the generic_handle_*() functions, and comments are updated for
clarity and consistency.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 17 insertions, 58 deletions

diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 897dfc552bb061..1b41078222f393 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -97,13 +97,6 @@ config GENERIC_MSI_IRQ_DOMAIN
 config IRQ_MSI_IOMMU
 	bool
 
-config HANDLE_DOMAIN_IRQ
-	bool
-
-# Legacy behaviour; architectures should call irq_{enter,exit}() themselves
-config HANDLE_DOMAIN_IRQ_IRQENTRY
-	bool
-
 config IRQ_TIMINGS
 	bool
 
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 7041698a7bffc4..2267e6527db3c2 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -651,7 +651,11 @@ int handle_irq_desc(struct irq_desc *desc)
  * generic_handle_irq - Invoke the handler for a particular irq
  * @irq:	The irq number to handle
  *
- */
+ * Returns:	0 on success, or -EINVAL if conversion has failed
+ *
+ * 		This function must be called from an IRQ context with irq regs
+ * 		initialized.
+  */
 int generic_handle_irq(unsigned int irq)
 {
 	return handle_irq_desc(irq_to_desc(irq));
@@ -661,77 +665,39 @@ EXPORT_SYMBOL_GPL(generic_handle_irq);
 #ifdef CONFIG_IRQ_DOMAIN
 /**
  * generic_handle_domain_irq - Invoke the handler for a HW irq belonging
- *                             to a domain, usually for a non-root interrupt
- *                             controller
+ *                             to a domain.
  * @domain:	The domain where to perform the lookup
  * @hwirq:	The HW irq number to convert to a logical one
  *
  * Returns:	0 on success, or -EINVAL if conversion has failed
  *
+ * 		This function must be called from an IRQ context with irq regs
+ * 		initialized.
  */
 int generic_handle_domain_irq(struct irq_domain *domain, unsigned int hwirq)
 {
+	WARN_ON_ONCE(!in_irq());
 	return handle_irq_desc(irq_resolve_mapping(domain, hwirq));
 }
 EXPORT_SYMBOL_GPL(generic_handle_domain_irq);
 
-#ifdef CONFIG_HANDLE_DOMAIN_IRQ
 /**
- * handle_domain_irq - Invoke the handler for a HW irq belonging to a domain,
- *                     usually for a root interrupt controller
+ * generic_handle_domain_nmi - Invoke the handler for a HW nmi belonging
+ *                             to a domain.
  * @domain:	The domain where to perform the lookup
  * @hwirq:	The HW irq number to convert to a logical one
- * @regs:	Register file coming from the low-level handling code
- *
- * 		This function must be called from an IRQ context.
  *
  * Returns:	0 on success, or -EINVAL if conversion has failed
- */
-int handle_domain_irq(struct irq_domain *domain,
-		      unsigned int hwirq, struct pt_regs *regs)
-{
-	struct pt_regs *old_regs = set_irq_regs(regs);
-	int ret;
-
-	/*
-	 * IRQ context needs to be setup earlier.
-	 */
-	WARN_ON(!in_irq());
-
-	ret = generic_handle_domain_irq(domain, hwirq);
-
-	set_irq_regs(old_regs);
-	return ret;
-}
-
-/**
- * handle_domain_nmi - Invoke the handler for a HW irq belonging to a domain
- * @domain:	The domain where to perform the lookup
- * @hwirq:	The HW irq number to convert to a logical one
- * @regs:	Register file coming from the low-level handling code
- *
- *		This function must be called from an NMI context.
  *
- * Returns:	0 on success, or -EINVAL if conversion has failed
- */
-int handle_domain_nmi(struct irq_domain *domain, unsigned int hwirq,
-		      struct pt_regs *regs)
+ * 		This function must be called from an NMI context with irq regs
+ * 		initialized.
+ **/
+int generic_handle_domain_nmi(struct irq_domain *domain, unsigned int hwirq)
 {
-	struct pt_regs *old_regs = set_irq_regs(regs);
-	int ret;
-
-	/*
-	 * NMI context needs to be setup earlier in order to deal with tracing.
-	 */
-	WARN_ON(!in_nmi());
-
-	ret = generic_handle_domain_irq(domain, hwirq);
-
-	set_irq_regs(old_regs);
-	return ret;
+	WARN_ON_ONCE(!in_nmi());
+	return handle_irq_desc(irq_resolve_mapping(domain, hwirq));
 }
 #endif
-#endif
 
 /* Dynamic interrupt handling */