64-bit time_t on 32-bit powerpc

[Mark Millard]

On 2017-Jun-5, at 1:54 PM, Justin Hibbits <jhibbits at freebsd.org> wrote:

> On Fri, Jun 2, 2017 at 11:45 PM, Justin Hibbits <jhibbits at freebsd.org> wrote:
>> Calling all powerpc(32) users,
>> 
>> Attached is a patch which changes the size of time_t from 32-bit to 64-bit
>> on powerpc.  ARM and MIPS already use 64-bit time_t, the only other holdout
>> is i386, which cannot be changed.  I want to get this in soon so there's
>> plenty of soak time before 12 is branched.  It works well enough for my
>> cases, but I want others to poke, prod, and try to break it.  Especially try
>> your favorite ports builds, and make sure things still a) build, and b) work
>> as expected.
>> 
>> Almost forgot, too... With powerpc64 users, the compat32 has been updated as
>> well, obviously.  So, some testing of that is needed, too.
>> 
>> - Justin
> 
> I was just informed I forgot a very crucial part of the patch -- the
> update to UPDATING:
> 
> 20170612:
>        The FreeBSD/powerpc platform now uses a 64-bit type for time_t.  This is
>        a very major incompatible change, so users of FreeBSD/powerpc must be
>        careful when performing source upgrades.  It is best to run 'make
>        installworld' from an alternate root system, either a live CD/memory
>        stick, or a temporary root partition.  Additionally, all ports must be
>        recompiled.
> 
> In short: Do _not_ try to reboot to the new kernel with existing
> userland.  Boot to an alternate userland and install from there.

What timing as far as live-update contexts go. . .

ino64 requires a new kernel boot with an old world still
in use: world must not have been updated first.

So it appears one should not try to jump from pre-ino64
to post-powerpc-64-bit-time_t in one step via a
live-system update sequence.

> Also, shortly after I sent out the patch, I realized I hadn't tested
> with TARGET_ARCH=powerpc64, which broke.  I'll send out an updated
> patch later tonight.


===
Mark Millard
markmi at dsl-only.net