On Fri, May 15, 2020 at 5:10 PM Thomas Gleixner <[email protected]> wrote: > > > 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 <[email protected]> > > 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); > +}
See my comment in patch 8. I see no great reason that this should open-code the conditional, except maybe that we don't have pt_regs here so the condition needs to be a bit different.
