[Buildroot] csky 8xx toolchain issue

[Romain Naour]

Hello Thomas,

Le 02/10/2021 à 20:25, Thomas Petazzoni a écrit :
> Hello Romain,
> 
> On Sat, 2 Oct 2021 17:58:24 +0200
> Romain Naour <romain.naour at gmail.com> wrote:
> 
>> The csky toolchain is still broken with recent host compiler and our CI will
>> switch to Debian bullseye soon.
>>
>> I tried to build with the latest upstream version of binutils, gcc and glibc and
>> nothing build.
>>
>> upstream gcc-11 doesn't support csky610 and csky860 needed for
>> qemu_csky610_virt_defconfig and qemu_csky860_virt_defconfig.
>>
>> qemu_csky807_virt_defconfig and qemu_csky810_virt_defconfig fail to build glibc
>> with the following error:
>>
>> glibc-2.34-9-g9acab0bba6a5a57323b1f94bf95b21618a9e5aa4/build/elf/librtld.os: in
>> function `__sync_fetch_and_add_2':
>>
>> build/host-gcc-initial-11.2.0/build/csky-buildroot-linux-gnuabiv2/libgcc/../../../libgcc/config/csky/linux-atomic.c:116:
>> undefined reference to `__kernel_cmpxchg'
>>
>> But even if the build succeeded there is no qemu binary to do a runtime test.
> 
> Considering these issues and the fact that there has been no updates in
> terms of C-SKY support for a long time, I think we should consider
> dropping support for the C-SKY CPU architecture.

csky860 will be supported by gcc 12:
https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=db92bd223e3957ee58b5a0c0fffd8b7766f1def3

But no sing of ck610.

This cpu architecture is really young so the toolchain support needs to be
maintained regularly. Especially since there is not upstream Qemu support to do
a runtime test.

For example, we know that ARC architecture is maintained by Synopsys because it
require a toolchain based on forked version of binutils and gcc. Also most of
the upstream work has been done over the years and backported/maintained into
Buildroot.

I don't like to have to remove csky due to toolchain build issues...

Best regards,
Romain


> 
> Best regards,
> 
> Thomas
>