On 02/26/2018 09:00 AM, Arnd Bergmann wrote:
On Sun, Feb 25, 2018 at 4:43 PM, Philipp Wagner
<lists@xxxxxxxxxxxxxxxxxx> wrote:
Am 22.02.2018 um 16:45 schrieb Arnd Bergmann:
While building the cross-toolchains, I noticed that overall, we can build almost
all linux target architectures with upstream binutils and gcc these days,
however there are still some exceptions, and I'd like to find out if anyone
has objections to removing the ones that do not have upstream support.
This are the four architectures I found:
[...]
* OpenRISC is a RISC architecture with a free license and an
active community. It seems to have lost a bit of steam after RISC-V
is rapidly taking over that niche, but there are chips out there and
the design isn't going away. Listing it here for completeness only
because there is no upstream gcc port yet, but this will hopefully
change in the future based on
https://lists.librecores.org/pipermail/openrisc/2018-January/000958.html
and I had no problems locating the gcc-7.x tree for building my
toolchains. The port is actively being maintained.
It's mostly mentioned in the mailing list thread you linked to, but just
for completeness in this thread:
The OpenRISC GCC port is maintained and regularly updated to newer GCC
versions. It is not, however, upstreamed to the FSF due to a single
missing FSF copyright assignment from a developer who has written large
parts of the initial port. All code which has copyright assignments in
place (binutils, GDB, etc.) has been upstreamed lately.
For GCC, Stafford Horne is actively working on rewriting the parts which
we don't have the FSF copyright assignment for (and unless something
very surprising happens, won't get). [If anyone wants to help, there's
GSoC project for it as well:
https://fossi-foundation.org/gsoc18-ideas#openrisc-gcc-port]
So I'd be very sad if the openrisc port gets dropped from Linux upstream.
Yes, definitely. What I was really trying to say here is I consider openrisc
an obvious exception to the 'no more ports without upstream gcc' rule
because of the above.
On a related note, has anyone successfully built an openrisc kernel with
llvm/clang? As we discussed for arch/hexagon/, that architecture is unlikely
to ever get an upstream gcc port, but like openrisc does have an upstream
llvm port and they actually use that.
Actually the LLVM port of or1k isn't upstream either. CCing whitequark,
who might know more about the (non-)plans of getting the backend
upstream. I also don't know of anyone having tried to build the openrisc
kernel with LLVM, would certainly be an interesting thing to try.
I know that x86 and arm64 mostly work with llvm, arm32 works in some of
the more common configurations at least (not big-endian or older CPUs
though) and some others probably work as well. I have already build both
gcc-5.5 and gcc-7.3 for openrisc and uploaded those to
https://www.kernel.org/pub/tools/crosstool/files/bin/, but if llvm works as
well, that could be one more reason to try to build a working set of
clang based cross toolchains.
Philipp
