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irqchip/mips-gic: Use effective affinity to unmask 

Commit 7778c4b27c ("irqchip: mips-gic: Use pcpu_masks to avoid reading
GIC_SH_MASK*") adjusted the way we handle masking interrupts to set &
clear the interrupt's bit in each pcpu_mask. This allows us to avoid
needing to read the GIC mask registers and perform a bitwise and of
their values with the pending & pcpu_masks.

Unfortunately this didn't quite work for IPIs, which were mapped to a
particular CPU/VP during initialisation but never set the affinity or
effective_affinity fields of their struct irq_desc. This led to them
losing their affinity when gic_unmask_irq() was called for them, and
they'd all become affine to cpu0.

Fix this by:

 1) Setting the effective affinity of interrupts in
    gic_shared_irq_domain_map(), which is where we actually map an
    interrupt to a CPU/VP. This ensures that the effective affinity mask
    is always valid, not just after explicitly setting affinity.

 2) Using an interrupt's effective affinity when unmasking it, which
    prevents gic_unmask_irq() from unintentionally changing which
    pcpu_mask includes an interrupt.


Fixes: 7778c4b27c ("irqchip: mips-gic: Use pcpu_masks to avoid reading GIC_SH_MASK*")
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: https://lkml.kernel.org/r/20170922062440.23701-3-paul.burton@imgtec.com
zero-colors
Paul Burton 2017-09-21 23:24:40 -07:00 committed by Thomas Gleixner
parent a08588ea48
commit d9f82930a5
1 changed files with 5 additions and 2 deletions
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7
drivers/irqchip/irq-mips-gic.c
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@ -175,14 +175,13 @@ static void gic_mask_irq(struct irq_data *d)
static void gic_unmask_irq(struct irq_data *d)
{
struct cpumask *affinity = irq_data_get_affinity_mask(d);
unsigned int intr = GIC_HWIRQ_TO_SHARED(d->hwirq);
unsigned int cpu;
write_gic_smask(intr);
gic_clear_pcpu_masks(intr);
cpu = cpumask_first_and(affinity, cpu_online_mask);
cpu = cpumask_first(irq_data_get_effective_affinity_mask(d));
set_bit(intr, per_cpu_ptr(pcpu_masks, cpu));
}
@ -420,13 +419,17 @@ static int gic_shared_irq_domain_map(struct irq_domain *d, unsigned int virq,
irq_hw_number_t hw, unsigned int cpu)
{
int intr = GIC_HWIRQ_TO_SHARED(hw);
struct irq_data *data;
unsigned long flags;
data = irq_get_irq_data(virq);
spin_lock_irqsave(&gic_lock, flags);
write_gic_map_pin(intr, GIC_MAP_PIN_MAP_TO_PIN | gic_cpu_pin);
write_gic_map_vp(intr, BIT(mips_cm_vp_id(cpu)));
gic_clear_pcpu_masks(intr);
set_bit(intr, per_cpu_ptr(pcpu_masks, cpu));
irq_data_update_effective_affinity(data, cpumask_of(cpu));
spin_unlock_irqrestore(&gic_lock, flags);
return 0;