Re: [Minios-devel] [UNIKRAFT RFC PATCH 2/2] plat/common: Add a trap function to handle Arm64 irq trap

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 09/11/2018 09:02, Jianyong Wu wrote:
> From: Wei Chen <wei.chen@xxxxxxx>
>
> Change-Id: I3652599f8385fc67a29ab2d9e67861590c0f9f6c
> Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
> ---
>   plat/common/arm/traps.c   | 27 +++++++++++++++++++++++++++
>   plat/kvm/arm/exceptions.S | 10 +++++++++-
>   2 files changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/plat/common/arm/traps.c b/plat/common/arm/traps.c
> index 43235be..257106b 100644
> --- a/plat/common/arm/traps.c
> +++ b/plat/common/arm/traps.c
> @@ -23,6 +23,7 @@
>   #include <string.h>
>   #include <uk/print.h>
>   #include <uk/assert.h>
> +#include <arm/gic-v2.h>
>   
>   static const char *exception_modes[]= {
>         "Synchronous Abort",
> @@ -68,3 +69,29 @@ void trap_el1_sync(struct __regs *regs, uint64_t far)
>         dump_registers(regs, far);
>         ukplat_crash();
>   }
> +
> +void trap_el1_irq(struct __regs *regs, uint64_t far)
> +{
> +       uint32_t stat, irq;
> +
> +       do {
> +               stat = gic_ack_irq();
> +               irq = stat & GICC_IAR_INTID_MASK;
> +
> +               uk_printd(DLVL_CRIT, "Unikraft: EL1 IRQ#%d trap caught\n", irq);
> +
> +               /*
> +                * TODO: Hanle IPI&SGI interrupts here
> +                */
> +               if (irq < GIC_MAX_IRQ) {
> +                       gic_eoi_irq(stat);
> +                       isb();
> +                       _ukplat_irq_handle((unsigned long)irq);
> +                       continue;
> +               }
Looking again at this code, could you explain why you EOI the interrupt before 
handling it?
> +
> +               break;
> +       } while (1);
> +
> +       ukplat_crash();
> +}
> diff --git a/plat/kvm/arm/exceptions.S b/plat/kvm/arm/exceptions.S
> index af039d8..194cd03 100644
> --- a/plat/kvm/arm/exceptions.S
> +++ b/plat/kvm/arm/exceptions.S
> @@ -119,6 +119,14 @@ el1_sync:
>         bl trap_el1_sync
>         LEAVE_TRAP 1
>   
> +.align 6
> +el1_irq:
> +       ENTER_TRAP 1
> +       msr daifclr, #4
> +       mov x0, sp
> +       bl trap_el1_irq
> +       LEAVE_TRAP 1
> +
>   /* Bad Abort numbers */
>   #define BAD_SYNC  0
>   #define BAD_IRQ   1
> @@ -169,7 +177,7 @@ ENTRY(vector_table)
>   
>   	/* Current Exception level with SP_EL1 */
>         vector_entry el1_sync           /* Synchronous EL1h       */
> -       vector_entry el1_irq_invalid    /* IRQ EL1h               */
> +       vector_entry el1_irq            /* IRQ EL1h               */
>         vector_entry el1_fiq_invalid    /* FIQ EL1h               */
>         vector_entry el1_error_invalid  /* Error EL1h             */
>   
Cheers,

--
Julien Grall

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