[PATCH v3 2/2] rseq/selftests: Add support for RISC-V

[Vincent Chen]

On Fri, Mar 4, 2022 at 5:50 AM Mathieu Desnoyers
<mathieu.desnoyers at efficios.com> wrote:
>
> ----- On Mar 3, 2022, at 2:16 AM, Vincent Chen vincent.chen at sifive.com wrote:
>
> > On Thu, Mar 3, 2022 at 12:38 AM Mathieu Desnoyers
> > <mathieu.desnoyers at efficios.com> wrote:
> >>
> [...]
>
> >> > +#if __ORDER_LITTLE_ENDIAN__ == 1234
> >>
> >> I think we'll want to standardize on this for endianness checking (same as
> >> the updated uapi rseq.h):
> >>
> >> #if defined(__BYTE_ORDER) ? (__BYTE_ORDER == __LITTLE_ENDIAN) :
> >> defined(__LITTLE_ENDIAN)
> >>
> >> We may have to change rseq-mips.h in the rseq selftests to do the same as well
> >> rather than
> >> using "# ifdef __BIG_ENDIAN".
> >>
> >
> > OK, I can follow it. However, I found the endianness checking in
> > include/uapi/linux/rseq.h is
> > #if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) ||
> > defined(__BIG_ENDIAN)
> >
> > It is a little different than what you mentioned early. Should I
> > follow the format in include/uapi/linux/rseq.h? or both formats are
> > OK?
> >
>
> The form "#if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || defined(__BIG_ENDIAN)
> is completely buggy. Don't use that.
>
> I've sent the fix to Peter to remove the offending #if here:
>
> https://lore.kernel.org/lkml/1445357149.71067.1643137248305.JavaMail.zimbra@efficios.com/T/#mbbad3961494feefb98cb6d092879e3ea41b33df8
>
> Please use the correct non-bogus form instead:
>
> #if defined(__BYTE_ORDER) ? (__BYTE_ORDER == __LITTLE_ENDIAN) : defined(__LITTLE_ENDIAN)
>
> Thanks,
>
> Mathieu
>

I understood. By the way, IIUC, the __BYTE_ORDER and __LITTLE_ENDIAN
are defined in the glibc endian.h. However, I find that no file in the
rseq folder includes the endian.h. Does it means I should include
<endian.h> in the rseq-riscv.h?

Thanks,
Vincent
>
> --
> Mathieu Desnoyers
> EfficiOS Inc.
> http://www.efficios.com