Re: [Qemu-devel] [PATCH 1/7] target-arm: use correct do_interrupt handler for AArch64 user mode

[Peter Maydell]

On 5 May 2014 17:00, Rob Herring <address@hidden> wrote:
> From: Rob Herring <address@hidden>
>
> User mode emulation should never get interrupts and thus should not
> use the system emulation exception handler function.

This is true, but arm_cpu_do_interrupt() is also a system
emulation exception handler function, so it's no better.

I assume we're doing this because we're about to add
code to aarch64_cpu_do_interrupt() which doesn't compile
in user mode, though you don't mention this in the commit
message.

> @@ -187,7 +187,11 @@ static void aarch64_cpu_class_init(ObjectClass *oc, void 
> *data)
>  {
>      CPUClass *cc = CPU_CLASS(oc);
>
> +#if defined(CONFIG_USER_ONLY)
> +    cc->do_interrupt = arm_cpu_do_interrupt;
> +#else
>      cc->do_interrupt = aarch64_cpu_do_interrupt;
> +#endif

I think you can simply only do the assignment ifndef
CONFIG_USER_ONLY (which will leave the pointer NULL
for user-mode) -- it will never be called (and if it does
it'll be easier to find the bug if it's a segfault than if it
tries to execute the 32 bit system mode interrupt code...)

thanks
-- PMM