Re: [PATCHv3 00/24] ILP32 support in ARM64

[Andy Lutomirski]

On 02/11/2015 11:57 AM, H.J. Lu wrote:
> > > > trivially satisfied if you consider x32 and x86_64 separate
> > > > compilation environments, but it's not related to the core issue: that
> > > > the definition of timespec violates core (not obscure) requirements of
> > > > both POSIX and C11. At the time you were probably unaware of the C11
> > > > requirement. Note that it's a LOT harder to effect change in the C
> > > > standard, so even if the Austin Group would be amenable to changing
> > > > the requirement for timespec to allow something like nseconds_t,
> > > > getting WG14 to make this change to work around a Linux/glibc mistake
> > > > does not sound practical.
> > >
> > > That is very unfortunate.  I consider it is too late for x32 to change.
> >
> > Why? It's hardly an incompatible ABI change, as long as the
> > kernel/libc fills the upper bits (for old programs that read them
> > based on the old headers) when structs are read from the kernel to the
> > application, and ignores the upper bits (potentially set or left
> > uninitialized by the application) when strings are passed from
> > userspace to the kernel. Newly built apps using the struct definition
> > with 32-bit tv_nsec would need new libc to ensure that the high bits
> > aren't interpreted, but this could be handled by symbol versioning.
>
> We have considered this option.  But since kernel wouldn't change
> tv_nsec/tv_usec handling just for x32, it wasn't selected.

Did anyone *ask* the kernel people (e.g. hpa)?

--Andy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/