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Re: [RFC PATCH] AARCH64/ILP32: introduce kernel time types
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Szabolcs Nagy <szabolcs dot nagy at arm dot com>
- Cc: Yury Norov <ynorov at caviumnetworks dot com>, Andreas Schwab <schwab at suse dot de>, <nd at arm dot com>, <libc-alpha at sourceware dot org>, <arnd at arndb dot de>, <vapier at gentoo dot org>, <cmetcalf at tilera dot com>, <pinskia at gmail dot com>, <cmetcalf at mellanox dot com>, <bamvor dot zhangjian at huawei dot com>, <catalin dot marinas at arm dot com>, <fweimer at redhat dot com>, <Prasun dot Kapoor at cavium dot com>, <maxim dot kuvyrkov at linaro dot org>
- Date: Tue, 28 Jun 2016 11:55:29 +0000
- Subject: Re: [RFC PATCH] AARCH64/ILP32: introduce kernel time types
- Authentication-results: sourceware.org; auth=none
- References: <1467103498-24243-1-git-send-email-ynorov at caviumnetworks dot com> <mvmshvxk4n6 dot fsf at hawking dot suse dot de> <20160628102000 dot GA24779 at yury-N73SV> <mvmk2h9k3qh dot fsf at hawking dot suse dot de> <20160628104105 dot GD24025 at yury-N73SV> <57725DE8 dot 80708 at arm dot com>
On Tue, 28 Jun 2016, Szabolcs Nagy wrote:
> i agree with andreas.
>
> i don't think kernel names should be involved here.
I also agree. The types in utmp have *nothing* to do with the kernel.
Kernel time types should not appear in any public glibc interfaces at all,
only in code translating between kernel and glibc interfaces.
> (ideally the on-disk format would be the same on all
> abis not just on the ilp32 and lp64 abi of the same arch,
> since the same rootfs may be mounted on different hosts
> with a proper multiarch setup.. and ideally the public
> struct types would not need any changes to make this work,
> they could be serialized into a portable format.)
Yes (subject to a question of whether we actually care about
endianness-independence of the on-disk format, or only about such cases as
AArch32 / AArch64 ILP32 / AArch64 LP64 all of same endianness). I think
the goal should be that the struct types in the headers are
POSIX-conforming on all architectures, with translation for file input /
output as needed so that applications with 32-bit and 64-bit time_t, and
applications for different ABI variants, can access the same files, those
files always storing 64-bit time values. So if any changes to utmp
structures are being made, let's make them in that direction.
--
Joseph S. Myers
joseph@codesourcery.com