Comment 1:

Labels changed: added os-openbsd, removed priority-triage.

Comment 2:

It is possible that the new "use the host linker" support will take care of this
automatically. 
Too bad we can't light a fire under the OpenBSD guys to bring their operating system
into the 21st century.

Comment 3:

It is possible to tell whether tcp_fixup has run already. Check whether the first word
of the TCP points at itself.
Before tcp_fixup, it does. Afterward, it does not. The signal handler can use this to
decide whether there is a valid m and g worth loading. The new "run Go on C threads"
code can do the same.
That should eliminate the need for the pthread_create hook hack. Let's do that anyway.
I've never felt completely comfortable trying to replace pthread_create.

Comment 4:

Also, this is probably a mistake: 
    // The main thread TCB is a static allocation - do not try to free it.
    if(!mainthread)
        free(oldtcb);
The pointer I was talking about that points at itself is the first word of the main tcb.
In the copy, it still points at the old tcb. Freeing the old tcb creates a dangling
pointer. I don't know what looks at it, but probably something does. Or if nothing does,
we could set that word to something faulty like 1 to mark that it is a "Go" tcb.

Comment 5:

Hi Russ,
    amd64 and i386 port of OpenBSD use the large variant of TCB which has the self pointer
you described
(http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/i386/include/tcb.h?rev=HEAD;content-type=text%2Fplain
and
http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/amd64/include/tcb.h?rev=HEAD;content-type=text%2Fplain)
    however arm uses the small tls (http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/arm/include/tcb.h?rev=HEAD;content-type=text%2Fplain).
See here for definition of tcb:
http://www.openbsd.org/cgi-bin/cvsweb/src/lib/librthread/tcb.h?rev=HEAD;content-type=text%2Fplain
i searched /usr/src for __tcb_self, and i don't find any explicit references to it in
the code,
@jsing, do you agree with the plan to use a bad __tcb_self to signify a Go tcb?

Comment 6:

Issue #4957 has been merged into this issue.

Comment 7:

This issue was closed by revision 960d708.

Status changed to Fixed.