Re: [PATCH] Raise the minimum GCC version to 5.2

From: Christophe Leroy
Date: Tue May 04 2021 - 02:33:38 EST

Le 04/05/2021 à 07:30, Alexander Dahl a écrit :
Hello Arnd,

Am Mon, May 03, 2021 at 11:25:21AM +0200 schrieb Arnd Bergmann:
On Mon, May 3, 2021 at 9:35 AM Alexander Dahl <ada@xxxxxxxxxxx> wrote:

Desktops and servers are all nice, however I just want to make you
aware, there are embedded users forced to stick to older cross
toolchains for different reasons as well, e.g. in industrial
environment. :-)

This is no show stopper for us, I just wanted to let you be aware.

Can you be more specific about what scenarios you are thinking of,
what the motivations are for using an old compiler with a new kernel
on embedded systems, and what you think a realistic maximum
time would be between compiler updates?

One reason might be certification. For certain industrial applications
like support for complex field bus protocols, you need to get your
devices tested by an external partner running extensive test suites.
This is time consuming and expensive.

Changing the toolchain of your system then, would be a massive change
which would require recertification, while you could argue just
updating a single component like the kernel and building everything
again, does not require the whole testing process again.

Not sure to follow you.

Our company provides systems for Air Trafic Control, so we have the same kind of assurance quality process, but then I can't understand why you would need to upgrade your kernel at all.

Today our system is based on GCC 5 and Kernel 4.14. At the time being we are using GCC 5.5 (Latest GCC 5) and kernel 4.14.232 (Latest 4.14.y). Kernel 4.14 is maintained until 2024.

The day we do an upgrade, we upgrade everything including the tool chain then we go for another 6 years without major changes/re-qualification, because we can't afford a new qualitication every now and then.

So really, I can't see your approach.