This patch avoids the need to read the GIC_SH_MASK* registers when decoding shared interrupts by setting & clearing the interrupt's bit in the appropriate CPU's pcpu_masks entry when masking or unmasking the interrupt. This effectively means that whilst an interrupt is masked we clear its bit in all pcpu_masks, which causes gic_handle_shared_int() to ignore it on all CPUs without needing to check GIC_SH_MASK*. In essence, we add a little overhead to masking or unmasking interrupts but in return reduce the overhead of the far more common task of decoding interrupts. Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx> Cc: Jason Cooper <jason@xxxxxxxxxxxxxx> Cc: Marc Zyngier <marc.zyngier@xxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxx --- Changes in v2: - Split pcpu_masks bit setting out of gic_setup_pcpu_masks() & rename to gic_clear_pcpu_masks(), avoiding confusing use of NR_CPUS. drivers/irqchip/irq-mips-gic.c | 52 +++++++++++++++++++++++++----------------- 1 file changed, 31 insertions(+), 21 deletions(-) diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c index 00153231376a..e2ab0cee9ff2 100644 --- a/drivers/irqchip/irq-mips-gic.c +++ b/drivers/irqchip/irq-mips-gic.c @@ -55,6 +55,15 @@ static struct irq_chip gic_level_irq_controller, gic_edge_irq_controller; DECLARE_BITMAP(ipi_resrv, GIC_MAX_INTRS); DECLARE_BITMAP(ipi_available, GIC_MAX_INTRS); +static void gic_clear_pcpu_masks(unsigned int intr) +{ + unsigned int i; + + /* Clear the interrupt's bit in all pcpu_masks */ + for_each_possible_cpu(i) + clear_bit(intr, per_cpu_ptr(pcpu_masks, i)); +} + static bool gic_local_irq_is_routable(int intr) { u32 vpe_ctl; @@ -133,24 +142,17 @@ static void gic_handle_shared_int(bool chained) unsigned int intr, virq; unsigned long *pcpu_mask; DECLARE_BITMAP(pending, GIC_MAX_INTRS); - DECLARE_BITMAP(intrmask, GIC_MAX_INTRS); /* Get per-cpu bitmaps */ pcpu_mask = this_cpu_ptr(pcpu_masks); - if (mips_cm_is64) { + if (mips_cm_is64) __ioread64_copy(pending, addr_gic_pend(), DIV_ROUND_UP(gic_shared_intrs, 64)); - __ioread64_copy(intrmask, addr_gic_mask(), - DIV_ROUND_UP(gic_shared_intrs, 64)); - } else { + else __ioread32_copy(pending, addr_gic_pend(), DIV_ROUND_UP(gic_shared_intrs, 32)); - __ioread32_copy(intrmask, addr_gic_mask(), - DIV_ROUND_UP(gic_shared_intrs, 32)); - } - bitmap_and(pending, pending, intrmask, gic_shared_intrs); bitmap_and(pending, pending, pcpu_mask, gic_shared_intrs); for_each_set_bit(intr, pending, gic_shared_intrs) { @@ -165,12 +167,23 @@ static void gic_handle_shared_int(bool chained) static void gic_mask_irq(struct irq_data *d) { - write_gic_rmask(BIT(GIC_HWIRQ_TO_SHARED(d->hwirq))); + unsigned int intr = GIC_HWIRQ_TO_SHARED(d->hwirq); + + write_gic_rmask(BIT(intr)); + gic_clear_pcpu_masks(intr); } static void gic_unmask_irq(struct irq_data *d) { - write_gic_smask(BIT(GIC_HWIRQ_TO_SHARED(d->hwirq))); + struct cpumask *affinity = irq_data_get_affinity_mask(d); + unsigned int intr = GIC_HWIRQ_TO_SHARED(d->hwirq); + unsigned int cpu; + + write_gic_smask(BIT(intr)); + + gic_clear_pcpu_masks(intr); + cpu = cpumask_first_and(affinity, cpu_online_mask); + set_bit(intr, per_cpu_ptr(pcpu_masks, cpu)); } static void gic_ack_irq(struct irq_data *d) @@ -239,7 +252,6 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *cpumask, unsigned int irq = GIC_HWIRQ_TO_SHARED(d->hwirq); cpumask_t tmp = CPU_MASK_NONE; unsigned long flags; - int i; cpumask_and(&tmp, cpumask, cpu_online_mask); if (cpumask_empty(&tmp)) @@ -252,9 +264,9 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *cpumask, write_gic_map_vp(irq, BIT(mips_cm_vp_id(cpumask_first(&tmp)))); /* Update the pcpu_masks */ - for (i = 0; i < min(gic_vpes, NR_CPUS); i++) - clear_bit(irq, per_cpu_ptr(pcpu_masks, i)); - set_bit(irq, per_cpu_ptr(pcpu_masks, cpumask_first(&tmp))); + gic_clear_pcpu_masks(irq); + if (read_gic_mask(irq)) + set_bit(irq, per_cpu_ptr(pcpu_masks, cpumask_first(&tmp))); cpumask_copy(irq_data_get_affinity_mask(d), cpumask); spin_unlock_irqrestore(&gic_lock, flags); @@ -405,18 +417,16 @@ static int gic_local_irq_domain_map(struct irq_domain *d, unsigned int virq, } static int gic_shared_irq_domain_map(struct irq_domain *d, unsigned int virq, - irq_hw_number_t hw, unsigned int vpe) + irq_hw_number_t hw, unsigned int cpu) { int intr = GIC_HWIRQ_TO_SHARED(hw); unsigned long flags; - int i; 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(vpe))); - for (i = 0; i < min(gic_vpes, NR_CPUS); i++) - clear_bit(intr, per_cpu_ptr(pcpu_masks, i)); - set_bit(intr, per_cpu_ptr(pcpu_masks, vpe)); + 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)); spin_unlock_irqrestore(&gic_lock, flags); return 0; -- 2.14.1