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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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
hifive-unleashed-5.1
Benjamin Herrenschmidt 2017-04-05 17:54:49 +10:00 committed by Michael Ellerman
parent 14d4ae5c4c
commit a978e13965
4 changed files with 9 additions and 42 deletions
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1
arch/powerpc/include/asm/smp.h
View File

@ -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);

40
arch/powerpc/kernel/irq.c
View File

@ -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

9
arch/powerpc/kernel/smp.c
View File

@ -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;
}

1
arch/powerpc/platforms/Kconfig.cputype
View File

@ -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