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Re: [PATCHv3 00/24] ILP32 support in ARM64
- From: Rich Felker <dalias at libc dot org>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: Catalin Marinas <catalin dot marinas at arm dot com>, Andrew Pinski <apinski at cavium dot com>, linux-arm-kernel at lists dot infradead dot org, LKML <linux-kernel at vger dot kernel dot org>, Andrew Pinski <pinskia at gmail dot com>, musl at lists dot openwall dot com, GNU C Library <libc-alpha at sourceware dot org>
- Date: Wed, 11 Feb 2015 14:25:58 -0500
- Subject: Re: [PATCHv3 00/24] ILP32 support in ARM64
- Authentication-results: sourceware.org; auth=none
- References: <20141002155217 dot GH32147 at e104818-lin dot cambridge dot arm dot com> <20150210181302 dot GA23886 at brightrain dot aerifal dot cx> <CAMe9rOqX-VpjZ+E-JCusk+e4Kpw1V1tsFq1Kjtai5DR9saKLaA at mail dot gmail dot com> <20150211190252 dot GB23507 at brightrain dot aerifal dot cx> <CAMe9rOoME1fct=Dk1YFeoJbayvhdsaCUBZCY2YD6jK58J7=MkA at mail dot gmail dot com>
On Wed, Feb 11, 2015 at 11:16:58AM -0800, H.J. Lu wrote:
> >> > I don't know if this has been discussed on libc-alpha yet or not, but
> >> > I think we need to open a discussion of how it relates to open glibc
> >> > bug #16437, which presently applies only to x32 (ILP32 ABI on x86_64):
> >> >
> >> > https://sourceware.org/bugzilla/show_bug.cgi?id=16437
> >>
> >> Please leave x32 out of this discussion. I have resolved this bug
> >> as WONTFIX.
> >
> > From the glibc side, I thought things went by a consensus process
> > these days, not the old WONTFIX regime of he who shall not be named.
> > If this is not fixed for x32, then x32 cannot provide a conforming C
> > environment and thus it's rather a toy target. But I think we should
> > discuss this on libc-alpha. In the mean time please leave it REOPENED.
>
> As I said in PR, the issue has been raised in Mar, 2012 when the
> x32 port was submitted. It has been decided that x32 won't conform
> to tv_nsec, blksize_t, and suseconds_t as long. I don't believe we
> will change them to conform to POSIX.
I briefly reviewed that discussion and I think the decision made was
about an obscure POSIX requirement about supporting at least one
compilation environment where certain types have rank <= long. This is
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.
Rich