Well now i feel like a real goose!
I cleaned out everything and started a fresh.
| ___|
__| _ \ | _ \ __ \
\__ \ ( | | ( | ) |
____/\___/ _|\___/____/
Solo5: Memory map: 512 MB addressable:
Solo5: unused @ (0x0 - 0xfffff)
Solo5: text @ (0x100000 - 0x21efff)
Solo5: rodata @ (0x21f000 - 0x24efff)
Solo5: data @ (0x24f000 - 0x30cfff)
Solo5: heap >= 0x30d000 < stack < 0x20000000
2018-06-22 08:34:29 -00:00: INF [application] hello
2018-06-22 08:34:30 -00:00: INF [application] hello
2018-06-22 08:34:31 -00:00: INF [application] hello
2018-06-22 08:34:32 -00:00: INF [application] hello
Solo5: solo5_exit(0) called
No warning, no problems.
it was as simple as
opam install mirage -y&& \
git clone git://github.com/mirage/mirage-skeleton.git
$HOME/devl/mirage-skeleton && \
cd $HOME/devl/mirage-skeleton/tutorial/hello && \
mirage configure -t ukvm && \
gmake depends && \
gmake
and then
doas ukvm-bin hello.ukvm
There is a patch on [email protected] for Ocaml 4.06 and OPAM 2.00rc2, I think
once that goes in, it might be time to announce MirageOS on OpenBSD to
[email protected].
Sorry about wasting your time mato, i have no explanation as to why it failed
or why it worked again, the only difference was a clean out of .opam and
24-36hours.
Cheers
Adam
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On June 21, 2018 8:03 PM, Martin Lucina <[email protected]> wrote:
>
>
> On Thursday, 21.06.2018 at 07:46, Adam Steen wrote:
>
> > > > Mirage-Skeleton Hello World Tutorial, I now find this causes as "
> > > >
> > > > mprotect W^X violation" on OpenBSD.
> > >
> > > That's err, odd. Do you get a "Warning: phdr[N] requests WRITE and EXEC
> > >
> > > permissions" when running ukvm-bin?
> >
> > Yes.
>
> Right, so your ELF is requesting such a segment, in which case the failure
>
> is expected (without manually disabling W^X for the ukvm-bin).
>
> > > When you write "causes a mprotect W^X violation", how does that actually
> > >
> > > manifest itself at run-time? Does ukvm-bin get killed? Or some other way?
> >
> > ukvm-bin gets killed by the kernel.
> >
> > "ukvm-bin: hello.ukvm: Warning: phdr[0] requests WRITE and EXEC permissions"
> >
> > "ukvm-bin: hello.ukbm: Not Supported"
>
> The second error would be from the mprotect() returning ENOTSUP, which is
>
> due to the W^X policy, and ukvm-bin is correctly aborting in that case.
>
> > Looks like I will have to dig a little deeper, I do recall something like
> > this happening soon after i got things working on a custom kernel. I am
> > awol again next week, but will try to nail down exactly what caused the
> > issue.
> >
> > Thanks for the confirmation about linux and a starting point with "readelf
> > -l"
>
> As I wrote initially, this looks like something in the MirageOS build on
>
> OpenBSD is generating a segment with W & X on it. You can double-confirm by
>
> e.g. building the same unikernel on Linux and seeing if it runs on OpenBSD.
>
> If it changed recently then it's possible that either a) you were
>
> previously running a kernel that did not enforce this or b) the build
>
> toolchain changed and/or due to a) you did not notice that it's producing W
>
> & X segments in the first place.
>
> I'd ask around on the OpenBSD lists and/or check the various clang / ld
>
> manual pages for any options that might affect this.
>
> -mato
