[PATCH v4 27/31] ARM: irq: Add irqstack helper

[Linus Walleij]

Add a helper to dispatch IRQ execution to the IRQ stack:
call_on_irq_stack() so we can explicitly issue handle_irq()
on the IRQ stack from a C program.

Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
 arch/arm/kernel/irq.c | 6 ++++++
 arch/arm/kernel/irq.h | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
index e1993e28a9ecfd80b55b2677253ac582467e6c14..f99d6b24d8ff56f901e4a817c61a1e57b7e532cc 100644
--- a/arch/arm/kernel/irq.c
+++ b/arch/arm/kernel/irq.c
@@ -43,6 +43,7 @@
 #include <asm/mach/irq.h>
 #include <asm/mach/time.h>
 
+#include "irq.h"
 #include "reboot.h"
 
 unsigned long irq_err_count;
@@ -71,6 +72,11 @@ static void __init init_irq_stacks(void)
 	}
 }
 
+void call_on_irq_stack(void (*fn)(void *), void *arg)
+{
+	call_with_stack(fn, arg, __this_cpu_read(irq_stack_ptr));
+}
+
 #ifdef CONFIG_SOFTIRQ_ON_OWN_STACK
 static void ____do_softirq(void *arg)
 {
diff --git a/arch/arm/kernel/irq.h b/arch/arm/kernel/irq.h
new file mode 100644
index 0000000000000000000000000000000000000000..80dd5bfe6403d68fc62fab30666d5645748d329f
--- /dev/null
+++ b/arch/arm/kernel/irq.h
@@ -0,0 +1,2 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+void call_on_irq_stack(void (*fn)(void *), void *arg);

-- 
2.48.1