Introduce an Alternate Toolchain option with gcc and binutils #3564
Conversation
klauskiwi
commented
Apr 15, 2020
•
klauskiwi
commented
- Introduces an "Alternate Toolchain" concept, where an alternate version of gcc and binutils can be defined (separate from buildroot's Toolchain)
- Make use of it on Hostboot, Hostboot-P8 and OCC-P8, which are packages that are known to not work with more recent GCC versions
- Move configurations to use the default buildroot GCC version (7.x at the time of this writing)
There was a problem hiding this comment.
Is this intended for just POWER8 or also POWER9?
This patch itself does it for the POWER9 hostboot, not the POWER8 one.
It's also a pretty terrible ugly hack to build YET ANOTHER toolchain (what are we up to now? PORE, PPE, 405, and the dual BE/LE ppc64). So, we're already at five, and this is a sixth. (or 4 then 5 if you want to argue the dual BE/LE is actually one).
What does this add to the build time? Can it be brought into the buildroot toolchain building target so I can stop needlessly building 101 toolchains every time I want to build a new op-build?
There was a problem hiding this comment.
I very strongly disagree with the first fragment of the commit message "In the ideal buildroot world".
It should read "In an ideal world, Hostboot would be a maintained piece of software." Because that is fundamentally what this is working around - that nobody is maintaining the versions of hostboot that anybody uses.
I enabled the alternate gcc for hostboot-p8, occ-p8 and hostboot which were the packages I couldn't build using gcc7. I created this draft PR to get comments and use the CI to exercise more configurations that I may not have tested locally.
I agree
It will probably add some time. I'll investigate a bit more if adding this as part of the SDK is possible, but I don't think that's trivial. i.e., I don't think ppe or pore are doing that |
There's actually another reason for this: This is necessary for long-term downstream releases where we need to keep hostboot and the such exactly the same, while rebasing the skiroot environment with a newer release (i.e., because the kernel or some other component is out of service) |
We are happy to take a set of pull requests for the master-p8 branch from the community to make it work on both the current and the newer GCC levels if that is something that the community thinks is important. |
I like this suggestion. Here's a hostboot pull request: open-power/hostboot#193 With these changes I was able to build master for P8 with GCC 8 when I tested in January. |
|
Please note that modernizing Hostboot et al to use more modern compiler is definitely critical, but not the main objective of carrying around an "alternate toolchain". We need to have the ability to rebase "only" the Skiroot environment without invalidating tests done to Hostboot, Skiboot and such. The move to the default gcc7 compiler was a way to exercise this, not exactly the end goal. |
Fix the ci/build-all-defconfigs.sh to consider SDK versions with GCC 6, 7 or 8. Signed-off-by: Klaus Heinrich Kiwi <[email protected]>
In the ideal buildroot world, there is one definition of a Toolchain
that will be used to build the entire set of packages used in a
distribution.
However, in the OpenPower world, this rule is not completely true, due
to:
1) The need to build for two different target architectures at once
(ppc64le and ppe42) - this is already addressed by the ppe42-gcc
and ppe42-binutils packages
2) The fact that some of the legacy packages are not actively
maintained, but still needed (such as Hostboot-P8), while other
packages are actively updated and could benefit using newer
compilers (Linux Kernel, Skiboot etc).
Considering that (1) is already solved, and that (2) is desirable, this
patch reuses the mechanism used by (1) but to create an "Alternate"
Toolchain (initially composed of gcc and binutils) that could be used by
packages that are not willing or able to move towards newer compilers.
Once in use by a subset of packages, this also may allow for downstream
branches to keep using an older toolchain, while buildroot is re-based,
without necessarily moving the snapshot where those packages were
tested. This could be useful, for example, for upgrading Skiroot
environment completely without touching Hostboot, OCC, HCODE or even
Skiboot for that matter.
Signed-off-by: Klaus Heinrich Kiwi <[email protected]>
Enable Hostboot-P8 to optionally use an Alternate Toolchain Signed-off-by: Klaus Heinrich Kiwi <[email protected]>
Enable OCC-P8 to optionally use an Alternate Toolchain Signed-off-by: Klaus Heinrich Kiwi <[email protected]>
Enable Hostboot to optionally use an Alternate Toolchain Signed-off-by: Klaus Heinrich Kiwi <[email protected]>
Enable OCC to optionally use an Alternate Toolchain Signed-off-by: Klaus Heinrich Kiwi <[email protected]>
In order to exercise the Alternate Toolchain mechanism, unset BR2_GCC_VERSION_6_X in order to use buildroot's default GCC 7, while also enabling the Alternate GCC for all OCC and Hostboot packages. Signed-off-by: Klaus Heinrich Kiwi <[email protected]>
|
Re-cycled into a new PR #4063 |
