1 files changed, 148 insertions, 0 deletions
diff --git a/patches/softirq__Disable_softirq_stacks_for_RT.patch b/patches/softirq__Disable_softirq_stacks_for_RT.patch
new file mode 100644
index 000000000000..653c914e2635
--- /dev/null
+++ b/patches/softirq__Disable_softirq_stacks_for_RT.patch
@@ -0,0 +1,148 @@
+Subject: softirq: Disable softirq stacks for RT
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Mon Jul 18 13:59:17 2011 +0200
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+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           | 4 ++++
+ arch/sh/kernel/irq.c                | 2 ++
+ arch/sparc/kernel/irq_64.c          | 2 ++
+ arch/x86/include/asm/irq_stack.h    | 3 +++
+ arch/x86/kernel/irq_32.c            | 2 ++
+ include/asm-generic/softirq_stack.h | 2 +-
+ 6 files changed, 14 insertions(+), 1 deletion(-)
+---
+diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
+index 72cb45393ef2..64bb1620df8c 100644
+--- a/arch/powerpc/kernel/irq.c
++++ b/arch/powerpc/kernel/irq.c
+@@ -588,6 +588,7 @@ 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. */
+@@ -606,6 +607,7 @@ 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)
+ {
+@@ -713,10 +715,12 @@ 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)
+ {
+diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
+index ef0f0827cf57..2d3eca8fee01 100644
+--- a/arch/sh/kernel/irq.c
++++ b/arch/sh/kernel/irq.c
+@@ -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)
+ {
+diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c
+index c8848bb681a1..41fa1be980a3 100644
+--- a/arch/sparc/kernel/irq_64.c
++++ b/arch/sparc/kernel/irq_64.c
+@@ -855,6 +855,7 @@ void __irq_entry handler_irq(int pil, struct pt_regs *regs)
+ 	set_irq_regs(old_regs);
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT
+ void do_softirq_own_stack(void)
+ {
+ 	void *orig_sp, *sp = softirq_stack[smp_processor_id()];
+@@ -869,6 +870,7 @@ void do_softirq_own_stack(void)
+ 	__asm__ __volatile__("mov %0, %%sp"
+ 			     : : "r" (orig_sp));
+ }
++#endif
+ 
+ #ifdef CONFIG_HOTPLUG_CPU
+ void fixup_irqs(void)
+diff --git a/arch/x86/include/asm/irq_stack.h b/arch/x86/include/asm/irq_stack.h
+index 562854c60808..ea0c5ab31da4 100644
+--- a/arch/x86/include/asm/irq_stack.h
++++ b/arch/x86/include/asm/irq_stack.h
+@@ -185,6 +185,7 @@
+ 			      IRQ_CONSTRAINTS, regs, vector);		\
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT
+ #define ASM_CALL_SOFTIRQ						\
+ 	"call %P[__func]				\n"
+ 
+@@ -201,6 +202,8 @@
+ 	__this_cpu_write(hardirq_stack_inuse, false);			\
+ }
+ 
++#endif
++
+ #else /* CONFIG_X86_64 */
+ /* System vector handlers always run on the stack they interrupted. */
+ #define run_sysvec_on_irqstack_cond(func, regs)				\
+diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
+index 044902d5a3c4..e5dd6da78713 100644
+--- a/arch/x86/kernel/irq_32.c
++++ b/arch/x86/kernel/irq_32.c
+@@ -132,6 +132,7 @@ int irq_init_percpu_irqstack(unsigned int cpu)
+ 	return 0;
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT
+ void do_softirq_own_stack(void)
+ {
+ 	struct irq_stack *irqstk;
+@@ -148,6 +149,7 @@ void do_softirq_own_stack(void)
+ 
+ 	call_on_stack(__do_softirq, isp);
+ }
++#endif
+ 
+ void __handle_irq(struct irq_desc *desc, struct pt_regs *regs)
+ {
+diff --git a/include/asm-generic/softirq_stack.h b/include/asm-generic/softirq_stack.h
+index eceeecf6a5bd..d3e2d81656e0 100644
+--- a/include/asm-generic/softirq_stack.h
++++ b/include/asm-generic/softirq_stack.h
+@@ -2,7 +2,7 @@
+ #ifndef __ASM_GENERIC_SOFTIRQ_STACK_H
+ #define __ASM_GENERIC_SOFTIRQ_STACK_H
+ 
+-#ifdef CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK
++#if defined(CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK) && !defined(CONFIG_PREEMPT_RT)
+ void do_softirq_own_stack(void);
+ #else
+ static inline void do_softirq_own_stack(void)