[tip: irq/core] genirq: Provide generic_handle_domain_irq_safe().

[tip-bot2 for Sebastian Andrzej Siewior]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     6a164c646999847b843e651f71c53dfaceb2c2b4
Gitweb:        https://git.kernel.org/tip/6a164c646999847b843e651f71c53dfaceb2c2b4
Author:        Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate:    Mon, 09 May 2022 16:04:08 +02:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Mon, 19 Sep 2022 15:08:38 +02:00

genirq: Provide generic_handle_domain_irq_safe().

commit 509853f9e1e7b ("genirq: Provide generic_handle_irq_safe()")
addressed the problem of demultiplexing interrupt handlers which are force
threaded on PREEMPT_RT enabled kernels which means that the demultiplexed
handler is invoked with interrupts enabled which triggers a lockdep
warning due to a non-irq safe lock acquisition.

The same problem exists for the irq domain based interrupt handling via
generic_handle_domain_irq() which has been reported against the AMD
pin-ctrl driver.

Provide generic_handle_domain_irq_safe() which can used from any context.

[ tglx: Split the usage sites out and massaged changelog ]

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/YnkfWFzvusFFktSt@xxxxxxxxxxxxx
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215954
---
 include/linux/irqdesc.h |  1 +
 kernel/irq/irqdesc.c    | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index 1cd4e36..844a8e3 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -169,6 +169,7 @@ int generic_handle_irq_safe(unsigned int irq);
  * conversion failed.
  */
 int generic_handle_domain_irq(struct irq_domain *domain, unsigned int hwirq);
+int generic_handle_domain_irq_safe(struct irq_domain *domain, unsigned int hwirq);
 int generic_handle_domain_nmi(struct irq_domain *domain, unsigned int hwirq);
 #endif
 
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 5db0230..a91f900 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -705,6 +705,30 @@ int generic_handle_domain_irq(struct irq_domain *domain, unsigned int hwirq)
 }
 EXPORT_SYMBOL_GPL(generic_handle_domain_irq);
 
+ /**
+ * generic_handle_irq_safe - Invoke the handler for a HW irq belonging
+ *			     to a domain from any context.
+ * @domain:	The domain where to perform the lookup
+ * @hwirq:	The HW irq number to convert to a logical one
+ *
+ * Returns:	0 on success, a negative value on error.
+ *
+ * This function can be called from any context (IRQ or process
+ * context). If the interrupt is marked as 'enforce IRQ-context only' then
+ * the function must be invoked from hard interrupt context.
+ */
+int generic_handle_domain_irq_safe(struct irq_domain *domain, unsigned int hwirq)
+{
+	unsigned long flags;
+	int ret;
+
+	local_irq_save(flags);
+	ret = handle_irq_desc(irq_resolve_mapping(domain, hwirq));
+	local_irq_restore(flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(generic_handle_domain_irq_safe);
+
 /**
  * generic_handle_domain_nmi - Invoke the handler for a HW nmi belonging
  *                             to a domain.