Missing file /usr/riscv64-linux-gnu/include/gnu/stubs-lp64.h

[Heinrich Schuchardt]

When trying to build EDK II with -mabi=lp64 on riscv64 we are hitting missing include /usr/riscv64-linux-gnu/include/gnu/stubs-lp64.h.

[Heinrich Schuchardt (xypron)]

The RISC-V architecture uses different privilege levels (M-mode, S-mode, U-mode). Depending on the mode different extensions of the instruction set are available. See the RISC-V profile specification in https://github.com/riscv/riscv-profiles/blob/main/profiles.adoc.

As in S-mode no floating point extensions are available floats and doubles have to be passed in integer registers. This is the lp64 ABI. Currently we lack a toolchain for softfloat (__riscv_float_abi_soft) RISC-V binaries.

[Akeo (pbatard)]

Please bear in mind that simply symlinking/copying /usr/riscv64-linux-gnu/include/gnu/stubs-lp64d.h as /usr/riscv64-linux-gnu/include/gnu/stubs-lp64.h does solve the compilation issues.

Right now, and for the past couple of years, people compiling EDK2 projects for RISC-V on Ubuntu (which includes anybody using GitHub Actions) will face an error unless they manually duplicate/symlink stubs-lp64d.h as stubs-lp64.h (See for instance the extra step needed in https://github.com/pbatard/EfiFs/blob/d77c3ab5f4ad990d5a685f9f11c6d5fac54b5ed1/.github/workflows/linux_gcc_edk2.yml#L64-L66), so I believe that the header should be added to the package installation regardless, especially as all it seems to do is provide empty stub definitions...

[Heinrich Schuchardt (xypron)]

EDK II and SCT for riscv64 build just fine without creating a stubs-lp64.h symlink.

See https://github.com/xypron/sct_release_test/blob/main/build_sct_riscv64/Dockerfile

Best regards

Heinrich