Commit a978e139 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Michael Ellerman
Browse files

powerpc/smp: Remove migrate_irq() custom implementation 



Some powerpc platforms use this to move IRQs away from a CPU being
unplugged. This function has several bugs such as not taking the right
locks or failing to NULL check pointers.

There's a new generic function doing exactly the same thing without all
the bugs, so let's use it instead.

mpe: The obvious place for the select of GENERIC_IRQ_MIGRATION is on
HOTPLUG_CPU, but that doesn't work. On some configs PM_SLEEP_SMP will
select HOTPLUG_CPU even though its dependencies are not met, which means
the select of GENERIC_IRQ_MIGRATION doesn't happen. That leads to the
build breaking. Fix it by moving the select of GENERIC_IRQ_MIGRATION to
SMP.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 14d4ae5c

arch/powerpc/include/asm/smp.h

+0 −1
Original line number Diff line number Diff line
@@ -62,7 +62,6 @@ extern void smp_generic_take_timebase(void); 
DECLARE_PER_CPU(unsigned int, cpu_pvr);



#ifdef CONFIG_HOTPLUG_CPU

extern void migrate_irqs(void);

int generic_cpu_disable(void);

void generic_cpu_die(unsigned int cpu);

void generic_set_cpu_dead(unsigned int cpu);

arch/powerpc/kernel/irq.c

+0 −40
Original line number Diff line number Diff line
@@ -442,46 +442,6 @@ u64 arch_irq_stat_cpu(unsigned int cpu) 
	return sum;

}



#ifdef CONFIG_HOTPLUG_CPU

void migrate_irqs(void)

{

	struct irq_desc *desc;

	unsigned int irq;

	static int warned;

	cpumask_var_t mask;

	const struct cpumask *map = cpu_online_mask;



	alloc_cpumask_var(&mask, GFP_KERNEL);



	for_each_irq_desc(irq, desc) {

		struct irq_data *data;

		struct irq_chip *chip;



		data = irq_desc_get_irq_data(desc);

		if (irqd_is_per_cpu(data))

			continue;



		chip = irq_data_get_irq_chip(data);



		cpumask_and(mask, irq_data_get_affinity_mask(data), map);

		if (cpumask_any(mask) >= nr_cpu_ids) {

			pr_warn("Breaking affinity for irq %i\n", irq);

			cpumask_copy(mask, map);

		}

		if (chip->irq_set_affinity)

			chip->irq_set_affinity(data, mask, true);

		else if (desc->action && !(warned++))

			pr_err("Cannot set affinity for irq %i\n", irq);

	}



	free_cpumask_var(mask);



	local_irq_enable();

	mdelay(1);

	local_irq_disable();

}

#endif



static inline void check_stack_overflow(void)

{

#ifdef CONFIG_DEBUG_STACKOVERFLOW

arch/powerpc/kernel/smp.c

+8 −1
Original line number Diff line number Diff line
@@ -439,7 +439,14 @@ int generic_cpu_disable(void) 
#ifdef CONFIG_PPC64

	vdso_data->processorCount--;

#endif

	migrate_irqs();

	/* Update affinity of all IRQs previously aimed at this CPU */

	irq_migrate_all_off_this_cpu();



	/* Give the CPU time to drain in-flight ones */

	local_irq_enable();

	mdelay(1);

	local_irq_disable();



	return 0;

}

arch/powerpc/platforms/Kconfig.cputype

+1 −0
Original line number Diff line number Diff line
@@ -373,6 +373,7 @@ config PPC_PERF_CTRS 


config SMP

	depends on PPC_BOOK3S || PPC_BOOK3E || FSL_BOOKE || PPC_47x

	select GENERIC_IRQ_MIGRATION

	bool "Symmetric multi-processing support"

	---help---

	  This enables support for systems with more than one CPU. If you have

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