Re: [RFC v2] linux-user/riscv: Add syscall riscv_hwprobe

[Richard Henderson]

On 6/3/23 08:50, Andrew Jones wrote:
> On Fri, Jun 02, 2023 at 07:58:30PM -0700, Richard Henderson wrote:
> > On 6/2/23 07:02, Andrew Jones wrote:
> > > > +struct riscv_hwprobe {
> > > > +    int64_t  key;
> > > > +    uint64_t value;
> > > > +};
> > >
> > > The above is all uapi so Linux's arch/riscv/include/uapi/asm/hwprobe.h
> > > should be picked up on Linux header update. You'll need to modify the
> > > script, scripts/update-linux-headers.sh, to do that by adding a new
> > > riscv-specific block. Hacking this by importing the header file manually
> > > is fine for an RFC, but that should be a separate patch or part of the
> > > syscall define hack patch. And hack patches should be clearly tagged as
> > > "NOT FOR MERGE".
> >
> >
> > Not true.  linux-user/ never looks at linux-headers/.
>
> Ah, thanks. I should have known better than to try and review a linux-user
> patch, since I know almost nothing about it! Is uapi like this usually
> duplicated, as was done in this patch?

Yes, because linux-headers is only for the "native" compiler, whereas linux-user requires 
the ABI of the guest.

If we were doing this all from scratch, we would mechanically parse and rewrite 
linux-headers.


r~