RTEMS ARM Toolchain: armv8.0-m and armv8.1-m arch support

[Tigran Tadevosyan]

Dear RTMES OS devel team,

The RTEMS ARM latest toolchain (based on v5.1 release) supports cortex-m7 which is using armv7-m architecture.

Are you planning to upgrade your toolchain version and add support for cortex-m33 and cortex-m55 CPUs which are using armv8.0-m and armv8.1-m architectures ?

Thank you.

Best Regards,
Tigran

[Joel Sherrill]

If you need a newer toolchain, you should use rtems6 (e.g. git master). It is using gcc 10.

We tend to not update the toolchains for release branches. And newer architecture versions would also be added to master, not the release branch.

Are there specific deficiencies on the master and its tool chain?

[Tigran Tadevosyan]

Hi Joel,

Thank you very much for your response.

As far as I understand “git master” contains only RTMES kernel source code, but not a toolchain. (please correct me if I wrong)

Would you please clarify where from can I get the newer RTEMS GCC 10 based toolchain ?
For example, for release 5.1.0 I have used RTEMS v5 RSB to build the toolchain.
How can I build newer GCC 10 based toolchain without having corresponding RTEMS v6 RSB ?
(As I know RTEMS using customised version of toolchain based on GCC and I have to compile RTEMS kernel using RTEMS toolchain).

Would you please advise ? Thank you.

Best Regards,
Tigran

[Joel Sherrill]

There is no GCC 10 RSB recipe for RTEMS 5. You could modify the arm gcc version in your local 5 branch based on what is in 6. You will need to keep the newlib version the same, but the gcc should be able to be changed.

I don't know what it would be called but a more bleeding edge gcc might be nice for a release branch. For rtems master, we refer to that as rtems7.

For sure, updating GCC past 7 on rtems5 will break some BSPs. At least some PowerPC BSPs need SPE support which was dropped after 7 and I think the ARM changed some compiler flags. But, in theory, there isn't anything wrong with having a newer GCC as an alternative. But it would have to be disclaimed that all testing for the release was done with GCC 7 and anything newer would be at some risk of breakage. And I don't know what the toolchain would be called. It isn't 6 and isn't 5.

[Tigran Tadevosyan]

Hi Joel,

Thanks a lot. I will change the GCC version in rtems-source-builder-5.1 to gcc 10.x and will try to build the new toolchain. After that will try to compile the latest "git master".

May I ask you please to clarity the sentence: "You could modify the arm gcc version in your local 5 branch based on what is in 6." ?

Best Regards,
Tigran

[Chris Johns]

Please reopen if this is an issue or please ask on the users list if help is needed.