[patch V5 07/38] x86/entry/64: Move do_softirq_own_stack() to C

Thomas Gleixner
2020-05-12T22:25:06Z

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@linutronix.de>
---
V5: Convert to the new helpers
---
arch/x86/entry/entry_64.S | 13 -------------
arch/x86/kernel/irq_64.c | 9 +++++++++
2 files changed, 9 insertions(+), 13 deletions(-)

--- 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.
--- 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 in
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);
+}