Re: [PATCH v1 09/14] xen/riscv: introduce do_unexpected_trap()

[Alistair Francis <alistair23@xxxxxxxxx>]

On Sat, Jan 21, 2023 at 1:00 AM Oleksii Kurochko
<oleksii.kurochko@xxxxxxxxx> wrote:
>
> The patch introduces the function the purpose of which is to print
> a cause of an exception and call "wfi" instruction.
>
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
> ---
>  xen/arch/riscv/traps.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/xen/arch/riscv/traps.c b/xen/arch/riscv/traps.c
> index dd64f053a5..fc25138a4b 100644
> --- a/xen/arch/riscv/traps.c
> +++ b/xen/arch/riscv/traps.c
> @@ -95,7 +95,19 @@ const char *decode_cause(unsigned long cause)
>      return decode_trap_cause(cause);
>  }
>
> -void __handle_exception(struct cpu_user_regs *cpu_regs)
> +static void do_unexpected_trap(const struct cpu_user_regs *regs)
>  {
> +    unsigned long cause = csr_read(CSR_SCAUSE);
> +
> +    early_printk("Unhandled exception: ");
> +    early_printk(decode_cause(cause));
> +    early_printk("\n");
> +
> +    // kind of die...
>      wait_for_interrupt();

We could put this in a loop, to ensure we never progress

Alistair

>  }
> +
> +void __handle_exception(struct cpu_user_regs *cpu_regs)
> +{
> +    do_unexpected_trap(cpu_regs);
> +}
> --
> 2.39.0
>
>