[patch V6 08/37] x86/entry/64: Move do_softirq_own_stack() to C

[Thomas Gleixner]

The first step to get rid of the ENTER/LEAVE_IRQ_STACK ASM macro maze.  Use
the new C code helpers to move do_softirq_own_stack() out of ASM code.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 3b8da9f09297..bdf8391b2f95 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1145,19 +1145,6 @@ SYM_FUNC_START(asm_call_on_stack)
 	ret
 SYM_FUNC_END(asm_call_on_stack)
 
-/* Call softirq on interrupt stack. Interrupts are off. */
-.pushsection .text, "ax"
-SYM_FUNC_START(do_softirq_own_stack)
-	pushq	%rbp
-	mov	%rsp, %rbp
-	ENTER_IRQ_STACK regs=0 old_rsp=%r11
-	call	__do_softirq
-	LEAVE_IRQ_STACK regs=0
-	leaveq
-	ret
-SYM_FUNC_END(do_softirq_own_stack)
-.popsection
-
 #ifdef CONFIG_XEN_PV
 /*
  * A note on the "critical region" in our callback handler.
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 12df3a4abfdd..62cff52e03c5 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/irq_stack.h>
 #include <asm/io_apic.h>
 #include <asm/apic.h>
 
@@ -70,3 +71,11 @@ int irq_init_percpu_irqstack(unsigned int cpu)
 		return 0;
 	return map_irq_stack(cpu);
 }
+
+void do_softirq_own_stack(void)
+{
+	if (irqstack_active())
+		__do_softirq();
+	else
+		run_on_irqstack(__do_softirq, NULL);
+}