Hi Jiri,
On 10 April 2017 at 18:29, Jiri Slaby <jslaby@xxxxxxx> wrote:
> From: Felix Fietkau <nbd@xxxxxxxx>
>
> This patch has been added to the 3.12 stable tree. If you have any
> objections, please let us know.
>
> ===============
>
> commit 6c356eda225e3ee134ed4176b9ae3a76f793f4dd upstream.
>
> With the IRQ stack changes integrated, the XRX200 devices started
> emitting a constant stream of kernel messages like this:
>
> [ 565.415310] Spurious IRQ: CAUSE=0x1100c300
>
> This is caused by IP0 getting handled by plat_irq_dispatch() rather than
> its vectored interrupt handler, which is fixed by commit de856416e714
> ("MIPS: IRQ Stack: Fix erroneous jal to plat_irq_dispatch").
>
> Fix plat_irq_dispatch() to handle non-vectored IPI interrupts correctly
> by setting up IP2-6 as proper chained IRQ handlers and calling do_IRQ
> for all MIPS CPU interrupts.
>
> Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
> Acked-by: John Crispin <john@xxxxxxxxxxx>
> Cc: linux-mips@xxxxxxxxxxxxxx
> Patchwork: https://patchwork.linux-mips.org/patch/15077/
> [james.hogan@xxxxxxxxxx: tweaked commit message]
> Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
> Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
Just to let you know that I cherry-picked this patch from LEDE source
for 4.4 and 4.9 stable but James pointed out that this patch fixes a
Mips IRQ bug introduced in later (4.10+) kernels. So we dropped it
from 4.4 and 4.9 plan as such. Thanks.
Regards,
Amit Pundir
> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
> ---
> arch/mips/lantiq/irq.c | 38 +++++++++++++++++---------------------
> 1 file changed, 17 insertions(+), 21 deletions(-)
>
> diff --git a/arch/mips/lantiq/irq.c b/arch/mips/lantiq/irq.c
> index eb3e18659630..1637f165deab 100644
> --- a/arch/mips/lantiq/irq.c
> +++ b/arch/mips/lantiq/irq.c
> @@ -268,6 +268,11 @@ static void ltq_hw5_irqdispatch(void)
> DEFINE_HWx_IRQDISPATCH(5)
> #endif
>
> +static void ltq_hw_irq_handler(struct irq_desc *desc)
> +{
> + ltq_hw_irqdispatch(irq_desc_get_irq(desc) - 2);
> +}
> +
> #ifdef CONFIG_MIPS_MT_SMP
> void __init arch_init_ipiirq(int irq, struct irqaction *action)
> {
> @@ -312,23 +317,19 @@ static struct irqaction irq_call = {
> asmlinkage void plat_irq_dispatch(void)
> {
> unsigned int pending = read_c0_status() & read_c0_cause() & ST0_IM;
> - unsigned int i;
> -
> - if ((MIPS_CPU_TIMER_IRQ == 7) && (pending & CAUSEF_IP7)) {
> - do_IRQ(MIPS_CPU_TIMER_IRQ);
> - goto out;
> - } else {
> - for (i = 0; i < MAX_IM; i++) {
> - if (pending & (CAUSEF_IP2 << i)) {
> - ltq_hw_irqdispatch(i);
> - goto out;
> - }
> - }
> + int irq;
> +
> + if (!pending) {
> + spurious_interrupt();
> + return;
> }
> - pr_alert("Spurious IRQ: CAUSE=0x%08x\n", read_c0_status());
>
> -out:
> - return;
> + pending >>= CAUSEB_IP;
> + while (pending) {
> + irq = fls(pending) - 1;
> + do_IRQ(MIPS_CPU_IRQ_BASE + irq);
> + pending &= ~BIT(irq);
> + }
> }
>
> static int icu_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
> @@ -353,11 +354,6 @@ static const struct irq_domain_ops irq_domain_ops = {
> .map = icu_map,
> };
>
> -static struct irqaction cascade = {
> - .handler = no_action,
> - .name = "cascade",
> -};
> -
> int __init icu_of_init(struct device_node *node, struct device_node *parent)
> {
> struct device_node *eiu_node;
> @@ -413,7 +409,7 @@ int __init icu_of_init(struct device_node *node, struct device_node *parent)
> mips_cpu_irq_init();
>
> for (i = 0; i < MAX_IM; i++)
> - setup_irq(i + 2, &cascade);
> + irq_set_chained_handler(i + 2, ltq_hw_irq_handler);
>
> if (cpu_has_vint) {
> pr_info("Setting up vectored interrupts\n");
> --
> 2.12.2
>