From: "H.J. Lu" <hjl.tools@gmail.com>
To: Rich Felker <dalias@libc.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Andrew Pinski <apinski@cavium.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Pinski <pinskia@gmail.com>,
musl@lists.openwall.com,
GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCHv3 00/24] ILP32 support in ARM64
Date: Wed, 11 Feb 2015 11:57:59 -0800 [thread overview]
Message-ID: <CAMe9rOrVGFcQN3J1-pkXWd9j4MaQv2QxPrA5cTtLPBPaQ2-zfw@mail.gmail.com> (raw)
In-Reply-To: <20150211194741.GI23507@brightrain.aerifal.cx>
>> > 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.
--
H.J.
next prev parent reply other threads:[~2015-02-11 19:57 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20141002155217.GH32147@e104818-lin.cambridge.arm.com>
2015-02-10 18:13 ` Rich Felker
2015-02-11 17:39 ` Catalin Marinas
2015-02-11 19:05 ` Szabolcs Nagy
2015-02-11 19:22 ` [musl] " H.J. Lu
2015-02-11 19:50 ` arnd
2015-02-11 20:12 ` Rich Felker
2015-02-11 20:47 ` Jens Gustedt
2015-02-11 21:02 ` arnd
2015-02-11 21:09 ` arnd
2015-02-11 21:37 ` [musl] " Rich Felker
2015-02-16 17:20 ` Arnd Bergmann
2015-02-16 17:51 ` [musl] " Rich Felker
2015-02-16 19:38 ` Arnd Bergmann
2015-02-12 8:12 ` Szabolcs Nagy
2015-02-12 17:07 ` Catalin Marinas
2015-02-11 19:21 ` Rich Felker
2015-02-12 18:17 ` Catalin Marinas
2015-02-12 18:59 ` arnd
2015-02-13 13:33 ` Catalin Marinas
2015-02-13 16:30 ` Rich Felker
2015-02-13 17:33 ` Catalin Marinas
2015-02-13 18:37 ` Rich Felker
2015-02-16 14:40 ` Arnd Bergmann
2015-02-16 15:38 ` Rich Felker
2015-02-16 16:54 ` Arnd Bergmann
2015-02-11 18:33 ` H.J. Lu
2015-02-11 19:02 ` Rich Felker
2015-02-11 19:16 ` H.J. Lu
2015-02-11 19:25 ` Rich Felker
2015-02-11 19:34 ` H.J. Lu
2015-02-11 19:47 ` Rich Felker
2015-02-11 19:57 ` H.J. Lu [this message]
2015-02-11 20:15 ` Andy Lutomirski
2015-02-12 15:50 ` Catalin Marinas
2015-02-12 16:13 ` Rich Felker
2015-02-12 16:30 ` H.J. Lu
2015-02-12 17:00 ` Rich Felker
2015-02-11 21:41 ` Joseph Myers
2015-02-11 19:04 ` Josiah Worcester
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