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

[Vincent Chen]

On Fri, Mar 4, 2022 at 2:50 PM Vincent Chen <vincent.chen at sifive.com> wrote:
>
> 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?

After tracing the hierarchy of include files, I found that endian.h is
included by pthread.h, and pthread.h is included by param_test.c.
Therefore, rseq-riscv.h can exclude endian.h. I will follow your
suggestions to modify my next version patch. Thank you.

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