Re: [PATCH v2 1/7] ia64: add __NR_old_getpagesize macro

[Arnd Bergmann <arnd@arndb.de>]

On Mon, Oct 1, 2018 at 4:18 PM Firoz Khan <firoz.khan@linaro.org> wrote:
>
> Hi Arnd,
>
> On Fri, 28 Sep 2018 at 17:41, Arnd Bergmann <arnd@arndb.de> wrote:
> >
> > On Thu, Sep 27, 2018 at 4:16 PM Firoz Khan <firoz.khan@linaro.org> wrote:
> > >
> > > Add __NR_old_getpagesize in order to not break old user space
> > > as it is reserved for backwards compatibility with old __NR_
> > > getpagesize.
> >
> > That description doesn't really make sense here.
>
> Sure I'll some more details. But rest of the patch looks good?
> This is some I was bit confused! In header there is no entry, but
> in system call table has the entry for the system call.

I think adding some macro for it makes sense, and the
__NR_old_getpagesize name you picked is fine for that.

I think generally speaking we want the unistd.h macros to
match up with the system call entry points, and there are
currently multiple ways they diverge:

- System calls have been removed from the kernels, and the
  macros in unistd.h are still there on some architectures but not
  others. This is something we should clean up /after/ you are
  done.

- System calls have a number but are not implemented on all
  architectures because they don't make sense (e.g. pk pkey_add).
  These should probably have an entry in kernel/sys_ni.c if they
  don't already have one.

- System calls have an entry but no macro, like the ia64
  old_getpagesize. I think if you encounter one of these,
  we need to fix them up before your series so we can
  complete the conversion to generated tables.

        Arnd