Re: [RFC] minimum gcc version for kernel: raise to gcc-4.3 or 4.6?

Russell King - ARM Linux
2017-01-02T12:23:47Z

On Sat, Dec 17, 2016 at 12:29:50PM +0100, Sebastian Andrzej Siewior wrote:
> A new version is understandable. But why is an old version required?
> One thing is an enterprise distro that is "current" or "supported" and still
> stuck with gcc 4.1 because that is the version they decided to include in
> their release. This is sad. But you might want to ask yourself why you want
> the latest kernel but an old gcc / binutils.

To help isolate changes.

If you constantly upgrade everything, how do you bug hunt for a breakage?
How do you know whether it's created by the kernel, or by (eg) a later
version of gcc miscompiling the kernel. You have a large amount of code
to start bug hunting through.

Sticking with particular tool versions long-term means that you build up
confidence in it - yes, sure, latent bugs exist, but it's easier to
bug hunt if you aren't constantly suspecting that your tools might be
broken.

For example, I build kernels with:

gcc binutils built on
32-bit ARM 4.7.4 2.25 April/May 2015
64-bit ARM 4.9.2 2.25.51.20150219 Feb/April 2015

I'm not anticipating upgrading them for some time yet - the only one
which may get upgraded is the 64-bit binutils since later kernels now
complain about a missing errata workaround in that toolchain version.

I do still have some older toolchains around on some of my ARM boxes
though, even a GCC 3 version with ARM TLS support for faster builds!

--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.