Building binaries without instruction compression

[galsanka]

Hello all,

I have been trying to build OpenTitan software from C sources using this tutorial: https://docs.opentitan.org/doc/ug/getting_started_sw/.

I want to generate the binaries without instruction compression. I built the riscv toolchain without the C extension (i.e. by using all the recommended flags except for --with-arch=rv32im when building). After that, I added and modified the toolchain configuration file to replace the default toolchain with the one I built. I also modified meson-init.sh to point to that configuration file.

Unfortunately, the build's compiler settings only change after adding the -f flag to ./meson-init.sh -r, which removes the previously working binaries built with the original working compiler. I don't want to happen, because compiling all the other binaries without compression doesn't work.

So my question is: is there a way to compile new c binaries without compressed instructions while keeping the original working binaries (e.g. boot_rom) for the rest of the system? Meson is not cooperating and only changes after deleting all other working files, even after adding an -r flag to reconfigure. Should I just compile them using my own build system instead of relying on OpenTitan's?

Thank you,
Georges

[imphil]

@silvestrst

[silvestrst]

Hi Georges, Thank you for your question. Am I understanding it correctly that you are trying to selectively compile some of the binaries without the `C` extension, whilst keeping all the rest built with the provided toolchain? If my above conclusion is correct, then I think that the project as is doesn't support this option. Moreover I think meason doesn't support mixing and matching of different toolchains - you can have "build" (usually x86 machine), host (rv32xx). There is this meason merged PR <mesonbuild/meson#5083> that allows to overlay cross files, but I have never tried it, and not sure whether it allows to override toolchain completely or just some options. A non ideal alternative <mesonbuild/meson#5125 (comment)> - the use-case is slightly different, here someone needs to build for N targets at the same time. I think I would look into the "--cross-file" overlay, if that is not helpful, then you would need to have a custom solution for your problem. @luís Marques <[email protected]> Adding Luis who has worked on the toolchains infrastructure for OpenTitan, just to double-check the above. P.S. Please let us know if you have further questions, and also it would be interesting to know what you went for in the end. Regards, Silvestrs

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On Tue, Mar 9, 2021 at 1:39 AM Georges Alsankary ***@***.***> wrote: Hello all, I have been trying to build OpenTitan software from C sources using this tutorial: https://docs.opentitan.org/doc/ug/getting_started_sw/. I want to generate the binaries without instruction compression. I built the riscv toolchain without the C extension (i.e. by using all the recommended flags except for --with-arch=rv32im <https://docs.opentitan.org/doc/ug/install_instructions/#compiler-toolchain> when building). After that, I added and modified the toolchain configuration file to replace the default toolchain with the one I built. I also modified meson-init.sh to point to that configuration file. Unfortunately, the build's compiler settings only change after adding the -f flag to ./meson-init.sh -r, which removes the previously working binaries built with the original working compiler. I don't want to happen, because compiling all the other binaries without compression doesn't work. So my question is: is there a way to compile new c binaries without compressed instructions while keeping the original working binaries (e.g. boot_rom) for the rest of the system? Meson is not cooperating and only changes after deleting all other working files, even after adding an -r flag to reconfigure. Should I just compile them using my own build system instead of relying on OpenTitan's? Thank you, Georges — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#5509>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ANWSLWUSYSHB54KLNCFRJV3TCV34HANCNFSM4Y2QFLWQ> .

[galsanka]

Thank you, @silvestrst!

There might have been a misunderstanding. What I wanted to know was whether we can create executables without instruction compression, and whether they'd run on OpenTitan if compiled.

Thanks again,

Georges

[silvestrst]

Hi Georges, I don't see why this would be an issue? Have you tried building without instruction compression and encountered any issues? Thanks, Silvestrs

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On Wed, Mar 10, 2021 at 5:54 PM Georges Alsankary ***@***.***> wrote: Thank you, @silvestrst <https://github.com/silvestrst>! There might have been a misunderstanding. What I wanted to know was whether we can create executables without instruction compression, and whether they'd run on OpenTitan if compiled. Thanks again, Georges — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#5509 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ANWSLWTB4SXARXRBVISWX33TC6P3XANCNFSM4Y2QFLWQ> .

[imphil]

Please reopen if this problem persists.