Re: [PATCH 06/11] irqchip/gic-v3: Configure SGIs as standard interrupts

Marc Zyngier
2020-05-20T10:24:50Z

Hi Sumit,

On 2020-05-20 10:52, Sumit Garg wrote:
> Hi Marc,
>
> On Tue, 19 May 2020 at 21:48, Marc Zyngier <maz@kernel.org> wrote:
>>
>> Change the way we deal with GICv3 SGIs by turning them into proper
>> IRQs, and calling into the arch code to register the interrupt range
>> instead of a callback.
>>
>> Signed-off-by: Marc Zyngier <maz@kernel.org>
>> ---
>> drivers/irqchip/irq-gic-v3.c | 91
>> +++++++++++++++++++++---------------
>> 1 file changed, 53 insertions(+), 38 deletions(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-v3.c
>> b/drivers/irqchip/irq-gic-v3.c
>> index 23d7c87da407..d57289057b75 100644
>> --- a/drivers/irqchip/irq-gic-v3.c
>> +++ b/drivers/irqchip/irq-gic-v3.c
>> @@ -36,6 +36,9 @@
>> #define FLAGS_WORKAROUND_GICR_WAKER_MSM8996 (1ULL << 0)
>> #define FLAGS_WORKAROUND_CAVIUM_ERRATUM_38539 (1ULL << 1)
>>
>> +#define GIC_IRQ_TYPE_PARTITION (GIC_IRQ_TYPE_LPI + 1)
>> +#define GIC_IRQ_TYPE_SGI (GIC_IRQ_TYPE_LPI + 2)
>> +
>> struct redist_region {
>> void __iomem *redist_base;
>> phys_addr_t phys_base;
>> @@ -657,38 +660,14 @@ static asmlinkage void __exception_irq_entry
>> gic_handle_irq(struct pt_regs *regs
>> if ((irqnr >= 1020 && irqnr <= 1023))
>> return;
>>
>> - /* Treat anything but SGIs in a uniform way */
>> - if (likely(irqnr > 15)) {
>> - int err;
>> -
>> - if (static_branch_likely(&supports_deactivate_key))
>> - gic_write_eoir(irqnr);
>> - else
>> - isb();
>> -
>> - err = handle_domain_irq(gic_data.domain, irqnr, regs);
>> - if (err) {
>> - WARN_ONCE(true, "Unexpected interrupt
>> received!\n");
>> - gic_deactivate_unhandled(irqnr);
>> - }
>> - return;
>> - }
>> - if (irqnr < 16) {
>> + if (static_branch_likely(&supports_deactivate_key))
>> gic_write_eoir(irqnr);
>> - if (static_branch_likely(&supports_deactivate_key))
>> - gic_write_dir(irqnr);
>> -#ifdef CONFIG_SMP
>> - /*
>> - * Unlike GICv2, we don't need an smp_rmb() here.
>> - * The control dependency from gic_read_iar to
>> - * the ISB in gic_write_eoir is enough to ensure
>> - * that any shared data read by handle_IPI will
>> - * be read after the ACK.
>> - */
>> - handle_IPI(irqnr, regs);
>> -#else
>> - WARN_ONCE(true, "Unexpected SGI received!\n");
>> -#endif
>> + else
>> + isb();
>> +
>> + if (handle_domain_irq(gic_data.domain, irqnr, regs)) {
>> + WARN_ONCE(true, "Unexpected interrupt received!\n");
>> + gic_deactivate_unhandled(irqnr);
>> }
>> }
>>
>> @@ -1136,11 +1115,11 @@ static void gic_send_sgi(u64 cluster_id, u16
>> tlist, unsigned int irq)
>> gic_write_sgi1r(val);
>> }
>>
>> -static void gic_raise_softirq(const struct cpumask *mask, unsigned
>> int irq)
>> +static void gic_ipi_send_mask(struct irq_data *d, const struct
>> cpumask *mask)
>> {
>> int cpu;
>>
>> - if (WARN_ON(irq >= 16))
>> + if (WARN_ON(d->hwirq >= 16))
>> return;
>>
>> /*
>> @@ -1154,7 +1133,7 @@ static void gic_raise_softirq(const struct
>> cpumask *mask, unsigned int irq)
>> u16 tlist;
>>
>> tlist = gic_compute_target_list(&cpu, mask,
>> cluster_id);
>> - gic_send_sgi(cluster_id, tlist, irq);
>> + gic_send_sgi(cluster_id, tlist, d->hwirq);
>> }
>>
>> /* Force the above writes to ICC_SGI1R_EL1 to be executed */
>> @@ -1163,10 +1142,36 @@ static void gic_raise_softirq(const struct
>> cpumask *mask, unsigned int irq)
>>
>> static void gic_smp_init(void)
>> {
>> - set_smp_cross_call(gic_raise_softirq);
>> + struct irq_fwspec sgi_fwspec = {
>> + .fwnode = gic_data.fwnode,
>> + };
>> + int base_sgi;
>> +
>> cpuhp_setup_state_nocalls(CPUHP_AP_IRQ_GIC_STARTING,
>> "irqchip/arm/gicv3:starting",
>> gic_starting_cpu, NULL);
>> +
>> + if (is_of_node(gic_data.fwnode)) {
>> + /* DT */
>> + sgi_fwspec.param_count = 3;
>> + sgi_fwspec.param[0] = GIC_IRQ_TYPE_SGI;
>> + sgi_fwspec.param[1] = 0;
>> + sgi_fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
>> + } else {
>> + /* ACPI */
>> + sgi_fwspec.param_count = 2;
>> + sgi_fwspec.param[0] = 0;
>> + sgi_fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
>> + }
>> +
>> + /* Register all 8 non-secure SGIs */
>> + base_sgi = __irq_domain_alloc_irqs(gic_data.domain, -1, 8,
>> + NUMA_NO_NODE, &sgi_fwspec,
>> + false, NULL);
>> + if (WARN_ON(base_sgi <= 0))
>> + return;
>> +
>> + set_smp_ipi_range(base_sgi, 8);
>> }
>>
>> static int gic_set_affinity(struct irq_data *d, const struct cpumask
>> *mask_val,
>> @@ -1215,6 +1220,7 @@ static int gic_set_affinity(struct irq_data *d,
>> const struct cpumask *mask_val,
>> }
>> #else
>> #define gic_set_affinity NULL
>> +#define gic_ipi_send_mask NULL
>> #define gic_smp_init() do { } while(0)
>> #endif
>>
>> @@ -1257,6 +1263,7 @@ static struct irq_chip gic_chip = {
>> .irq_set_irqchip_state = gic_irq_set_irqchip_state,
>> .irq_nmi_setup = gic_irq_nmi_setup,
>> .irq_nmi_teardown = gic_irq_nmi_teardown,
>> + .ipi_send_mask = gic_ipi_send_mask,
>> .flags = IRQCHIP_SET_TYPE_MASKED |
>> IRQCHIP_SKIP_SET_WAKE |
>> IRQCHIP_MASK_ON_SUSPEND,
>
> It looks like you missed to update "struct irq_chip gic_eoimode1_chip"
> with similar change as follows:
>
> diff --git a/drivers/irqchip/irq-gic-v3.c
> b/drivers/irqchip/irq-gic-v3.c
> index 2a09634..ceef63b 100644
> --- a/drivers/irqchip/irq-gic-v3.c
> +++ b/drivers/irqchip/irq-gic-v3.c
> @@ -1291,6 +1291,7 @@ static struct irq_chip gic_eoimode1_chip = {
> .irq_set_vcpu_affinity = gic_irq_set_vcpu_affinity,
> .irq_nmi_setup = gic_irq_nmi_setup,
> .irq_nmi_teardown = gic_irq_nmi_teardown,
> + .ipi_send_mask = gic_ipi_send_mask,
> .flags = IRQCHIP_SET_TYPE_MASKED |
> IRQCHIP_SKIP_SET_WAKE |
> IRQCHIP_MASK_ON_SUSPEND,
>
> After incorporating this change, your patch-set works fine on my
> Developerbox machine.

Huh, well spotted. As I said, it has only been tested as guests,
hence not hitting this path. Time to throw it at the bigger stuff.

Thanks,

M.
--
Jazz is not dead. It just smells funny...