Re: RISC-V nommu support v2

From: Christoph Hellwig
Date: Mon Jun 24 2019 - 09:17:07 EST


On Mon, Jun 24, 2019 at 02:08:50PM +0100, Vladimir Murzin wrote:
> True, yet my observation was that elf2flt utility assumes that address
> space cannot exceed 32-bit (for header and absolute relocations). So,
> from my limited point of view straightforward way to guarantee that would
> be to build incoming elf in 32-bit mode (it is why I mentioned COMPAT/ILP32).
>
> Also one of your patches expressed somewhat related idea
>
> "binfmt_flat isn't the right binary format for huge executables to
> start with"
>
> Since you said there is no support for compat/ilp32, probably I'm missing some
> toolchain magic?

There is no magic except for the tiny elf2flt patch, which for
now is just in the buildroot repo pointed to in the cover letter
(and which I plan to upstream once the kernel support has landed
in Linus' tree). We only support 32-bit code and data address spaces,
but we otherwise use the normal RISC-V ABI, that is 64-bit longs and
pointers.