linux-kernel - [irqchip: irq/irqchip-next] irq: add generic_handle_arch

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Date:   Tue, 26 Oct 2021 10:16:06 -0000
From:   "irqchip-bot for Mark Rutland" <tip-bot2@...utronix.de>
To:     linux-kernel@...r.kernel.org
Cc:     Mark Rutland <mark.rutland@....com>, Marc Zyngier <maz@...nel.org>,
        Guo Ren <guoren@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: [irqchip: irq/irqchip-next] irq: add generic_handle_arch_irq()

The following commit has been merged into the irq/irqchip-next branch of irqchip:

Commit-ID:     a1b09501971435ef213251891753afb0d7f3d27a
Gitweb:        https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms/a1b09501971435ef213251891753afb0d7f3d27a
Author:        Mark Rutland <mark.rutland@....com>
AuthorDate:    Wed, 20 Oct 2021 11:24:06 +01:00
Committer:     Mark Rutland <mark.rutland@....com>
CommitterDate: Mon, 25 Oct 2021 10:05:27 +01:00

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@....com>
Reviewed-by: Marc Zyngier <maz@...nel.org>
Reviewed-by: Guo Ren <guoren@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
---
 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 c8293c8..988c225 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 221d80c..2718200 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