Various panics while using HWPMC on ARM64

[Ed Maste]

On 8 December 2015 at 14:34, Zbigniew Bodek <zbb at semihalf.com> wrote:
> Hello,
>
> I encountered some problems with FreeBSD on ARM64 while using hwpmc.
> Some of the errors that I found are listed below:
>
> * panic: Unknown kernel exception 0 esr_el1 2000000
> * panic: data abort in critical section or under mutex
> * panic: VFP exception in the kernel
> * panic: Unknown kernel exception 21 esr_el1 86000006

Can you add these notes to PR 204686? I think there are SMP issues in
arm64 hwpmc that need to be resolved.