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Subject: softirq: Disable softirq stacks for RT
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 18 Jul 2011 13:59:17 +0200
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.21-rt34.tar.xz
Disable extra stacks for softirqs. We want to preempt softirqs and
having them on special IRQ-stack does not make this easier.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/powerpc/kernel/irq.c | 2 ++
arch/powerpc/kernel/misc_32.S | 2 ++
arch/powerpc/kernel/misc_64.S | 2 ++
arch/sh/kernel/irq.c | 2 ++
arch/sparc/kernel/irq_64.c | 2 ++
arch/x86/kernel/irq_32.c | 2 ++
arch/x86/kernel/irq_64.c | 2 ++
include/linux/interrupt.h | 2 +-
8 files changed, 15 insertions(+), 1 deletion(-)
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -753,10 +753,12 @@ void *mcheckirq_ctx[NR_CPUS] __read_most
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)
{
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -31,6 +31,7 @@
* We store the saved ksp_limit in the unused part
* of the STACK_FRAME_OVERHEAD
*/
+#ifndef CONFIG_PREEMPT_RT
_GLOBAL(call_do_softirq)
mflr r0
stw r0,4(r1)
@@ -46,6 +47,7 @@
stw r10,THREAD+KSP_LIMIT(r2)
mtlr r0
blr
+#endif
/*
* void call_do_irq(struct pt_regs *regs, void *sp);
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -27,6 +27,7 @@
.text
+#ifndef CONFIG_PREEMPT_RT
_GLOBAL(call_do_softirq)
mflr r0
std r0,16(r1)
@@ -37,6 +38,7 @@
ld r0,16(r1)
mtlr r0
blr
+#endif
_GLOBAL(call_do_irq)
mflr r0
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -148,6 +148,7 @@ void irq_ctx_exit(int cpu)
hardirq_ctx[cpu] = NULL;
}
+#ifndef CONFIG_PREEMPT_RT
void do_softirq_own_stack(void)
{
struct thread_info *curctx;
@@ -175,6 +176,7 @@ 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)
{
--- a/arch/sparc/kernel/irq_64.c
+++ b/arch/sparc/kernel/irq_64.c
@@ -854,6 +854,7 @@ void __irq_entry handler_irq(int pil, st
set_irq_regs(old_regs);
}
+#ifndef CONFIG_PREEMPT_RT
void do_softirq_own_stack(void)
{
void *orig_sp, *sp = softirq_stack[smp_processor_id()];
@@ -868,6 +869,7 @@ void do_softirq_own_stack(void)
__asm__ __volatile__("mov %0, %%sp"
: : "r" (orig_sp));
}
+#endif
#ifdef CONFIG_HOTPLUG_CPU
void fixup_irqs(void)
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -131,6 +131,7 @@ int irq_init_percpu_irqstack(unsigned in
return 0;
}
+#ifndef CONFIG_PREEMPT_RT
void do_softirq_own_stack(void)
{
struct irq_stack *irqstk;
@@ -147,6 +148,7 @@ void do_softirq_own_stack(void)
call_on_stack(__do_softirq, isp);
}
+#endif
void __handle_irq(struct irq_desc *desc, struct pt_regs *regs)
{
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -72,7 +72,9 @@ int irq_init_percpu_irqstack(unsigned in
return map_irq_stack(cpu);
}
+#ifndef CONFIG_PREEMPT_RT
void do_softirq_own_stack(void)
{
run_on_irqstack_cond(__do_softirq, NULL);
}
+#endif
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -560,7 +560,7 @@ struct softirq_action
asmlinkage void do_softirq(void);
asmlinkage void __do_softirq(void);
-#ifdef __ARCH_HAS_DO_SOFTIRQ
+#if defined(__ARCH_HAS_DO_SOFTIRQ) && !defined(CONFIG_PREEMPT_RT)
void do_softirq_own_stack(void);
#else
static inline void do_softirq_own_stack(void)
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