softirq: Move do_softirq_own_stack() to generic asm header

To avoid include recursion hell move the do_softirq_own_stack() related
content into a generic asm header and include it from all places in arch/
which need the prototype.

This allows architectures to provide an inline implementation of
do_softirq_own_stack() without introducing a lot of #ifdeffery all over the
place.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210210002513.289960691@linutronix.de

diff --git a/arch/parisc/kernel/irq.c b/arch/parisc/kernel/irq.c
index 49cd6d2..1632d52 100644
--- a/arch/parisc/kernel/irq.c
+++ b/arch/parisc/kernel/irq.c
@@ -17,6 +17,7 @@
 #include <linux/types.h>
 #include <asm/io.h>
 
+#include <asm/softirq_stack.h>
 #include <asm/smp.h>
 #include <asm/ldcw.h>
 
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 6b1eca5..96296d3 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -65,6 +65,7 @@
 #include <asm/livepatch.h>
 #include <asm/asm-prototypes.h>
 #include <asm/hw_irq.h>
+#include <asm/softirq_stack.h>
 
 #ifdef CONFIG_PPC64
 #include <asm/paca.h>
diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c
index f8a8b942..a1a2f75 100644
--- a/arch/s390/kernel/irq.c
+++ b/arch/s390/kernel/irq.c
@@ -27,6 +27,7 @@
 #include <asm/irq.h>
 #include <asm/hw_irq.h>
 #include <asm/stacktrace.h>
+#include <asm/softirq_stack.h>
 #include "entry.h"
 
 DEFINE_PER_CPU_SHARED_ALIGNED(struct irq_stat, irq_stat);
diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
index ab5f790..ef0f082 100644
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -20,6 +20,7 @@
 #include <linux/uaccess.h>
 #include <asm/thread_info.h>
 #include <cpu/mmu_context.h>
+#include <asm/softirq_stack.h>
 
 atomic_t irq_err_count;
 
diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c
index 3ec9f14..c8848bb 100644
--- a/arch/sparc/kernel/irq_64.c
+++ b/arch/sparc/kernel/irq_64.c
@@ -42,6 +42,7 @@
 #include <asm/head.h>
 #include <asm/hypervisor.h>
 #include <asm/cacheflush.h>
+#include <asm/softirq_stack.h>
 
 #include "entry.h"
 #include "cpumap.h"
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 0b79efc..044902d 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -22,6 +22,7 @@
 
 #include <asm/apic.h>
 #include <asm/nospec-branch.h>
+#include <asm/softirq_stack.h>
 
 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index b88fdb9..f335c39 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -20,6 +20,7 @@
 #include <linux/sched/task_stack.h>
 
 #include <asm/cpu_entry_area.h>
+#include <asm/softirq_stack.h>
 #include <asm/irq_stack.h>
 #include <asm/io_apic.h>
 #include <asm/apic.h>
diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild
index 267f6df..bd68418 100644
--- a/include/asm-generic/Kbuild
+++ b/include/asm-generic/Kbuild
@@ -51,6 +51,7 @@
 mandatory-y += serial.h
 mandatory-y += shmparam.h
 mandatory-y += simd.h
+mandatory-y += softirq_stack.h
 mandatory-y += switch_to.h
 mandatory-y += timex.h
 mandatory-y += tlbflush.h
diff --git a/include/asm-generic/softirq_stack.h b/include/asm-generic/softirq_stack.h
new file mode 100644
index 0000000..eceeecf
--- /dev/null
+++ b/include/asm-generic/softirq_stack.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __ASM_GENERIC_SOFTIRQ_STACK_H
+#define __ASM_GENERIC_SOFTIRQ_STACK_H
+
+#ifdef CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK
+void do_softirq_own_stack(void);
+#else
+static inline void do_softirq_own_stack(void)
+{
+	__do_softirq();
+}
+#endif
+
+#endif
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index f0b918f..967e257 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -569,15 +569,6 @@ struct softirq_action
 asmlinkage void do_softirq(void);
 asmlinkage void __do_softirq(void);
 
-#ifdef CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK
-void do_softirq_own_stack(void);
-#else
-static inline void do_softirq_own_stack(void)
-{
-	__do_softirq();
-}
-#endif
-
 extern void open_softirq(int nr, void (*action)(struct softirq_action *));
 extern void softirq_init(void);
 extern void __raise_softirq_irqoff(unsigned int nr);
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 9d71046..9908ec4a 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -26,6 +26,8 @@
 #include <linux/tick.h>
 #include <linux/irq.h>
 
+#include <asm/softirq_stack.h>
+
 #define CREATE_TRACE_POINTS
 #include <trace/events/irq.h>