Commit b8d490c3 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

Merge branch 'irq/core-v6' of... 

Merge branch 'irq/core-v6' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into irq/core

Pull hardirq and softirq nesting updates from Frederic Weisbecker,
which fix nesting related stack overruns such as:

  http://lkml.kernel.org/r/1378330796.4321.50.camel%40pasglop



Beyond being a fix, this series also optimizes and reorganizes arch
hardirq/softirq stack processing to be faster and more robust.

Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parents 8a60d42d 62d26c82

arch/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -390,6 +390,16 @@ config HAVE_UNDERSCORE_SYMBOL_PREFIX 
	  Some architectures generate an _ in front of C symbols; things like

	  module loading and assembly files need to know about this.



config HAVE_IRQ_EXIT_ON_IRQ_STACK

	bool

	help

	  Architecture doesn't only execute the irq handler on the irq stack

	  but also irq_exit(). This way we can process softirqs on this irq

	  stack instead of switching to a new one when we call __do_softirq()

	  in the end of an hardirq.

	  This spares a stack switch and improves cache usage on softirq

	  processing.



#

# ABI hall of shame

#

arch/metag/kernel/irq.c

+19 −33
Original line number Diff line number Diff line
@@ -159,19 +159,12 @@ void irq_ctx_exit(int cpu) 


extern asmlinkage void __do_softirq(void);



asmlinkage void do_softirq(void)

void do_softirq_own_stack(void)

{

	unsigned long flags;

	struct thread_info *curctx;

	union irq_ctx *irqctx;

	u32 *isp;



	if (in_interrupt())

		return;



	local_irq_save(flags);



	if (local_softirq_pending()) {

	curctx = current_thread_info();

	irqctx = softirq_ctx[smp_processor_id()];

	irqctx->tinfo.task = curctx->task;
@@ -190,13 +183,6 @@ asmlinkage void do_softirq(void) 
		  "D1Ar5", "D0Ar6", "D0Re0", "D1Re0", "D0.4", "D1RtP",

		  "D0.5"

		);

		/*

		 * Shouldn't happen, we returned above if in_interrupt():

		 */

		WARN_ON_ONCE(softirq_count());

	}



	local_irq_restore(flags);

}

#endif

arch/parisc/kernel/irq.c

+2 −15
Original line number Diff line number Diff line
@@ -499,22 +499,9 @@ static void execute_on_irq_stack(void *func, unsigned long param1) 
	*irq_stack_in_use = 1;

}



asmlinkage void do_softirq(void)

void do_softirq_own_stack(void)

{

	__u32 pending;

	unsigned long flags;



	if (in_interrupt())

		return;



	local_irq_save(flags);



	pending = local_softirq_pending();



	if (pending)

	execute_on_irq_stack(__do_softirq, 0);



	local_irq_restore(flags);

}

#endif /* CONFIG_IRQSTACKS */

arch/powerpc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -138,6 +138,7 @@ config PPC 
	select OLD_SIGSUSPEND

	select OLD_SIGACTION if PPC32

	select HAVE_DEBUG_STACKOVERFLOW

	select HAVE_IRQ_EXIT_ON_IRQ_STACK



config EARLY_PRINTK

	bool

arch/powerpc/kernel/irq.c

+1 −16
Original line number Diff line number Diff line
@@ -593,7 +593,7 @@ void irq_ctx_init(void) 
	}

}



static inline void do_softirq_onstack(void)

void do_softirq_own_stack(void)

{

	struct thread_info *curtp, *irqtp;
@@ -611,21 +611,6 @@ static inline void do_softirq_onstack(void) 
		set_bits(irqtp->flags, &curtp->flags);

}



void do_softirq(void)

{

	unsigned long flags;



	if (in_interrupt())

		return;



	local_irq_save(flags);



	if (local_softirq_pending())

		do_softirq_onstack();



	local_irq_restore(flags);

}



irq_hw_number_t virq_to_hw(unsigned int virq)

{

	struct irq_data *irq_data = irq_get_irq_data(virq);

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