Re: [PATCH V8 2/2] irqchip/loongarch-avec: Add AVEC irqchip support

[Huacai Chen]

Hi, Tianyang,

On Thu, Aug 8, 2024 at 2:52 PM Tianyang Zhang <zhangtianyang@xxxxxxxxxxx> wrote:
>
> Hi, Thomas
>
> Thank you for your feedback.
>
> 在 2024/8/8 上午6:01, Thomas Gleixner 写道:
>
> >> +    guard(raw_spinlock_irqsave)(&loongarch_avec.lock);
> >> +
> >> +    for (i = 0; i < nr_irqs; i++) {
> >> +            d = irq_domain_get_irq_data(domain, virq + i);
> >> +            if (d) {
> >> +                    clear_free_vector(d);
> >> +                    irq_domain_reset_irq_data(d);
> >> +
> > Stray newline, but the more important question is what kfree()'s 'd'?
> >
> > AFAICT, nothing. So that's a memory leak, no?
> With my understand , 'd' as 'struct irq_data' can be free at public
> irqdomain process, and really miss a kfree targeting 'struct chip_data'
> >
> >> +static int __init avecintc_init(struct irq_domain *parent)
> >> +{
> >> +    parent_irq = irq_create_mapping(parent, INT_AVEC);
> >> +    if (!parent_irq) {
> >> +            pr_err("Failed to mapping hwirq\n");
> >> +            ret = -EINVAL;
> >> +            goto out_remove_domain;
> >> +    }
> >> +    irq_set_chained_handler_and_data(parent_irq, avecintc_irq_dispatch, NULL);
> >> +
> >> +    ret = irq_matrix_init();
> >> +    if (ret < 0) {
> >> +            pr_err("Failed to init irq matrix\n");
> >> +            goto out_remove_domain;
> > Which still leaves the disfunct chained handler installed and the
> > mapping intact.
>
> There is indeed a problem here, but we have not found a similar approach
> for reference.
>
> Is it reasonable to replace here with handle_bad_irq in case of failure?
> or is there any other more suitable way. We hope you can give us some
> suggestions, thank you very much
Maybe we can move irq_set_chained_handler_and_data(parent_irq,
avecintc_irq_dispatch, NULL) after the checking of irq_matrix_init().

Huacai

>
> >> +#endif
> >> +    value = iocsr_read64(LOONGARCH_IOCSR_MISC_FUNC);
> >> +    value |= IOCSR_MISC_FUNC_AVEC_EN;
> >> +    iocsr_write64(value, LOONGARCH_IOCSR_MISC_FUNC);
> >> +
> >> +    return ret;
> >> +
> >> +out_remove_domain:
> >> +    irq_domain_remove(loongarch_avec.domain);
> >> +out_free_handle:
> >> +    irq_domain_free_fwnode(loongarch_avec.fwnode);
> >> +out:
> >> +    return ret;
> >> +}
> >> +
> >> +static int __init pch_msi_parse_madt(union acpi_subtable_headers *header,
> >> +                                 const unsigned long end)
> >> +{
> >> +    struct acpi_madt_msi_pic *pchmsi_entry = (struct acpi_madt_msi_pic *)header;
> >> +
> >> +    msi_base_addr = pchmsi_entry->msg_address - AVEC_MSG_OFFSET;
> > What validates that msi_base_addr has none of the lower 16 bits set, as
> > they are required to be zero to make MSI message composing work, right?
>
> This operation originates from some hardware designs.
>
> In 3C6000, either eiointc or avecintc can be the parent controller for
> MSI interrupts and these two controllers have different MSI msg address.
>
> In our platform design scheme, we fix avec-msg-address to the address of
> (eiointc-msg-address - 0x100000). Therefore, here we need to subtract
> AVEC_MSG_OFFSET from the msg_address obtained by MCFG
>
> The main purpose of the design that users of 3C6000 can freely choose
> the version of the Linux kernel that supports loongarch (regardless of
> whether AVEC is supported or not) without having to change the firmware
>
>
> Thanks again
>
> Tianyang
>