[PATCH V6 16/20] riscv: compat: vdso: Add rv32 VDSO base code implementation

[Arnd Bergmann]

On Thu, Feb 24, 2022 at 9:54 AM <guoren at kernel.org> wrote:
>
> From: Guo Ren <guoren at linux.alibaba.com>
>
> There is no vgettimeofday supported in rv32 that makes simple to
> generate rv32 vdso code which only needs riscv64 compiler. Other
> architectures need change compiler or -m (machine parameter) to
> support vdso32 compiling. If rv32 support vgettimeofday (which
> cause C compile) in future, we would add CROSS_COMPILE to support
> that makes more requirement on compiler enviornment.

I think it's just a bug that rv32 doesn't have the vdso version of the
time syscalls. Fixing that is of course independent of the compat support,
but I think you need that anyway, and it would be better to start
out by building the compat vdso with the correct
architecture level.

At least this should be a lot easier than on arch/arm64 because you
can assume that an rv64 compiler is able to also build rv32 output.

        Arnd