irq: add generic_handle_arch_irq()

Several architectures select GENERIC_IRQ_MULTI_HANDLER and branch to
handle_arch_irq() without performing any entry accounting.

Add a generic wrapper to handle the common irqentry work when invoking
handle_arch_irq(). Where an architecture needs to perform some entry
accounting itself, it will need to invoke handle_arch_irq() itself.

In subsequent patches it will become the responsibilty of the entry code
to set the irq regs when entering an IRQ (rather than deferring this to
an irqchip handler), so generic_handle_arch_irq() is made to set the irq
regs now. This can be redundant in some cases, but is never harmful as
saving/restoring the old regs nests safely.

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

diff --git a/include/linux/irq.h b/include/linux/irq.h
index c8293c8..988c225 100644 (file)
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -1261,6 +1261,7 @@ int __init set_handle_irq(void (*handle_irq)(struct pt_regs *));
  * top-level IRQ handler.
  */
 extern void (*handle_arch_irq)(struct pt_regs *) __ro_after_init;
+asmlinkage void generic_handle_arch_irq(struct pt_regs *regs);
 #else
 #ifndef set_handle_irq
 #define set_handle_irq(handle_irq)             \

diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 221d80c..2718200 100644 (file)
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -14,6 +14,8 @@
 #include <linux/interrupt.h>
 #include <linux/kernel_stat.h>
 
+#include <asm/irq_regs.h>
+
 #include <trace/events/irq.h>
 
 #include "internals.h"
@@ -226,4 +228,20 @@ int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
        handle_arch_irq = handle_irq;
        return 0;
 }
+
+/**
+ * generic_handle_arch_irq - root irq handler for architectures which do no
+ *                           entry accounting themselves
+ * @regs:      Register file coming from the low-level handling code
+ */
+asmlinkage void noinstr generic_handle_arch_irq(struct pt_regs *regs)
+{
+       struct pt_regs *old_regs;
+
+       irq_enter();
+       old_regs = set_irq_regs(regs);
+       handle_arch_irq(regs);
+       set_irq_regs(old_regs);
+       irq_exit();
+}
 #endif