On 12/03/2021 10:32, Michael Ellerman wrote:
Alan Modra <amo...@gmail.com> writes:
On Wed, Mar 10, 2021 at 01:44:57PM +0100, Christophe Leroy wrote:
Le 10/03/2021 à 13:25, Alan Modra a écrit :
On Wed, Mar 10, 2021 at 08:33:37PM +1100, Alexey Kardashevskiy wrote:
One more question - the older version had a construct "DEFINED (.TOC.) ?
.TOC. : ..." in case .TOC. is not defined (too old ld? too old gcc?) but the
newer patch seems assuming it is always defined, when was it added? I have
the same check in SLOF, for example, do I still need it?
.TOC. symbol support was first added 2012-11-06, so you need
binutils-2.24 or later to use .TOC. as a symbol.
As of today, minimum requirement to build kernel is binutils 2.23, see
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.kernel.org_doc_html_latest_process_changes.html-23current-2Dminimal-2Drequirements&d=DwIDAw&c=jf_iaSHvJObTbx-siA1ZOg&r=uzpscot8Q8p-51o1Gp1vnzKV94bfny2qmUdVe821lv0&m=SYi605mn0I1hf1QoHuvHXtS_Z-R6JJHbzS34cEtV2Tk&s=47ckf3yxVcP6RwRb8D9viYOQSWpf6rXrnWj4YM4OTJ0&e=
Yes, and arch/powerpc/Makefile complains about 2.24. So for powerpc
that means you need to go to at least 2.25.
Not quite. It only complains for little endian builds, and only if you
have stock 2.24, it will allow a 2.24.<something>.
I do most of my builds with 2.34, so I have no issue with newer
binutils. But we try not to increase the minimum version too rapidly to
accommodate folks using older and/or "Enterprise" distros that are stuck
on old toolchains.
I think we are within our rights to increase the minimum requirement for
powerpc builds, if it brings advantages we can identify.
The way to do that would be to add a new check in our arch Makefile that
rejects the older versions.
The upstream llvm just learnt to handle the .TOC. symbol in linker
scripts so we may delay the future for a bit longer :) @dja wanted
upstream llvm anyway and the currently supported llvm 10.xx is not much
value for our experiments.
https://github.com/llvm/llvm-project/commit/e4f385d89448393b4d213339bbbbbbaa42b49489
--
Alexey
