rumpkernel and bhyve: triple faults

[Fabian Freyer]

On 10 Mar 2018, at 23:46, Martin Lucina wrote:
> On Friday, 09.03.2018 at 18:45, Fabian Freyer wrote:
>> On 6 Mar 2018, at 7:45, Fabian Freyer wrote:
>>> I’m not sure where to go from here. Is this a bug in bhyve(4), should these
>>> values be initialised somehow, or should I patch rumpkernel(7) to skip this check
>>> when running on bhyve(4)?
>
> You probably want to use a serial console rather than VGA on bhyve in any
> case, so you'll want to add the appropriate checks to hypervisor.c and
> cons.c.

I’ve started on a patch, but the check should fail if bios_crtc_base is unset
anyways.

>> A build on Linux (which boots fine) shows [bios_com1_base, bios_crtc_base] not to
>> be uninitialised:
>> 00000000003e3480 g     O .bss	0000000000000002 bios_com1_base
>> 00000000003e44a0 g     O .bss	0000000000000002 bios_crtc_base
>
> When you write "which boots fine", I presume you're referring to booting on
> bhyve?

Yes. The rumprun kernel built on Linux boots fine (including serial output by default
on Linux. The one built on FreeBSD triple faults, due to accessing 0x2.

>> Further down the rabbit hole, this goes on in rumprun.o:
>>
>> On Linux, bios_crtc_base is not a local symbol:
>> 0000000000000002       O *COM*  0000000000000002 bios_crtc_base
>> 0000000000000002       O *COM*  0000000000000002 bios_com1_base
>>
>> While on FreeBSD, they are marked as local:
>> 0000000000000002 l     O *COM*  0000000000000002 bios_crtc_base
>> 0000000000000002 l     O *COM*  0000000000000002 bios_com1_base
>
> That seems wrong. Can you try and force the toolchain to use the more
> recent GNU ld from devel/binutils and see if that fixes the problem?

I’m using GNU Binutils from devel/binutils:

pkg list binutils | grep /usr/local/bin/ld
/usr/local/bin/ld
/usr/local/bin/ld.bfd
/usr/local/bin/ld.gold

$(x86_64-rumprun-netbsd-gcc -print-prog-name=ld) -v
GNU ld (GNU Binutils) 2.30

Fabian
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