[PATCH v2 07/17] irq: add generic_handle_arch_irq()

From: Mark Rutland
Date: Tue Oct 26 2021 - 05:25:51 EST


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@xxxxxxx>
Reviewed-by: Marc Zyngier <maz@xxxxxxxxxx>
Reviewed-by: Guo Ren <guoren@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
include/linux/irq.h | 1 +
kernel/irq/handle.c | 18 ++++++++++++++++++
2 files changed, 19 insertions(+)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index c8293c817646..988c225eef2d 100644
--- 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 221d80c31e94..27182003b879 100644
--- 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
--
2.11.0