Commit f2c50921 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Arnd Bergmann
Browse files

arch/*: Disable softirq stacks on PREEMPT_RT. 



PREEMPT_RT preempts softirqs and the current implementation avoids
do_softirq_own_stack() and only uses __do_softirq().

Disable the unused softirqs stacks on PREEMPT_RT to save some memory and
ensure that do_softirq_own_stack() is not used bwcause it is not expected.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
parent b13baccc

arch/arm/kernel/irq.c

+2 −1
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ static void __init init_irq_stacks(void) 
	}

}



#ifndef CONFIG_PREEMPT_RT

static void ____do_softirq(void *arg)

{

	__do_softirq();
@@ -80,7 +81,7 @@ void do_softirq_own_stack(void) 
	call_with_stack(____do_softirq, NULL,

			__this_cpu_read(irq_stack_ptr));

}



#endif

#endif



int arch_show_interrupts(struct seq_file *p, int prec)

arch/parisc/kernel/irq.c

+2 −0
Original line number Diff line number Diff line
@@ -480,10 +480,12 @@ static void execute_on_irq_stack(void *func, unsigned long param1) 
	*irq_stack_in_use = 1;

}



#ifndef CONFIG_PREEMPT_RT

void do_softirq_own_stack(void)

{

	execute_on_irq_stack(__do_softirq, 0);

}

#endif

#endif /* CONFIG_IRQSTACKS */



/* ONLY called from entry.S:intr_extint() */

arch/powerpc/kernel/irq.c

+4 −0
Original line number Diff line number Diff line
@@ -611,6 +611,7 @@ static inline void check_stack_overflow(void) 
	}

}



#ifndef CONFIG_PREEMPT_RT

static __always_inline void call_do_softirq(const void *sp)

{

	/* Temporarily switch r1 to sp, call __do_softirq() then restore r1. */
@@ -629,6 +630,7 @@ static __always_inline void call_do_softirq(const void *sp) 
		   "r11", "r12"

	);

}

#endif



static __always_inline void call_do_irq(struct pt_regs *regs, void *sp)

{
@@ -747,10 +749,12 @@ void *mcheckirq_ctx[NR_CPUS] __read_mostly; 
void *softirq_ctx[NR_CPUS] __read_mostly;

void *hardirq_ctx[NR_CPUS] __read_mostly;



#ifndef CONFIG_PREEMPT_RT

void do_softirq_own_stack(void)

{

	call_do_softirq(softirq_ctx[smp_processor_id()]);

}

#endif



irq_hw_number_t virq_to_hw(unsigned int virq)

{

arch/s390/include/asm/softirq_stack.h

+2 −1
Original line number Diff line number Diff line
@@ -5,9 +5,10 @@ 
#include <asm/lowcore.h>

#include <asm/stacktrace.h>



#ifndef CONFIG_PREEMPT_RT

static inline void do_softirq_own_stack(void)

{

	call_on_stack(0, S390_lowcore.async_stack, void, __do_softirq);

}



#endif

#endif /* __ASM_S390_SOFTIRQ_STACK_H */

arch/sh/kernel/irq.c

+2 −0
Original line number Diff line number Diff line
@@ -149,6 +149,7 @@ void irq_ctx_exit(int cpu) 
	hardirq_ctx[cpu] = NULL;

}



#ifndef CONFIG_PREEMPT_RT

void do_softirq_own_stack(void)

{

	struct thread_info *curctx;
@@ -176,6 +177,7 @@ void do_softirq_own_stack(void) 
		  "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"

	);

}

#endif

#else

static inline void handle_one_irq(unsigned int irq)

{