Re: [PATCH v4 00/24] ILP32 for ARM64

Catalin Marinas
2015-04-16T14:27:25Z

On Thu, Apr 16, 2015 at 01:19:14PM +0200, Dr. Philipp Tomsich wrote:
> Just for the record (and to avoid anyone wasting their time on what’s available
> today): we are migrating this over to option (a) now, even though we would
> prefer to see option (b) implemented.
>
> If we get a consensus on (b) in the next couple of days, we’ll redo things for
> option (b). If not, we will have an implementation for option (a) available that
> we can hopefully all agree on merging.

When you post, please include the libc-alpha list (I think they are fine
with cross-posting), maybe only for the cover letter as that's where the
useful discussion seems to happen.

It's interesting to re-read some older posts on x32 (it's not just
time_t affected, though probably that the most visible):

https://lwn.net/Articles/457089/
https://sourceware.org/ml/libc-alpha/2012-03/msg00487.html
https://sourceware.org/ml/libc-alpha/2012-03/msg00574.html

Basically for x32 POSIX compliance doesn't seem too critical. IIUC, the
x32 wasn't added to solve a 32-bit compatibility problem but as a
potential optimisation for specific cases.

On ARM OTOH, (one of?) the main goal for AArch64 ILP32 is to offer a
solution for 32-bit code when AArch32 is not present (and potentially
slightly more optimal than AArch32 but not necessarily when compared to
LP64).

--
Catalin