i386 Go programs crash on amd64

[Peter Wemm]

On 5/23/14, 3:53 PM, Peter Jeremy wrote:
> I've been playing with Go (lang/go) and found that i386 Go binaries
> segfault when run on amd64 (9.x, 10.x or HEAD).  I've narrowed it down
> to the LDT handling but am not sure whether it's on the FreeBSD or Go
> side.
>
> As far as I can see, the i386 binary is correctly calling i386_set_ldt()
> and the i386_set_ldt() emulation in the amd64 kernel matches the i386
> kernel - but the net result doesn't work.
>
> Can anyone offer any suggestions as to how to resolve this?
>
We don't emulate i386_set_ldt().

The 32 bit version of libc on amd64 has a different implementation that 
calls sysarch(I386_SET_FSBASE, ..) and friends.  Normally this is 
handled transparently by static linking, but obviously that's an issue 
for Go.

-Peter