From: Arnd Bergmann <arnd@arndb.de>
To: Andreas Schwab <schwab@suse.de>
Cc: linux-arm-kernel@lists.infradead.org,
        Yury Norov <ynorov@caviumnetworks.com>, pinskia@gmail.com,
        Prasun.Kapoor@caviumnetworks.com, catalin.marinas@arm.com,
        Nathan_Lynch@mentor.com, linux-kernel@vger.kernel.org, agraf@suse.de,
        klimov.linux@gmail.com,
        Andrew Pinski <Andrew.Pinski@caviumnetworks.com>, broonie@kernel.org,
        jan.dakinevich@gmail.com, Andrew Pinski <apinski@cavium.com>,
        ddaney.cavm@gmail.com, bamvor.zhangjian@huawei.com,
        philipp.tomsich@theobroma-systems.com, andrey.konovalov@linaro.org,
        christoph.muellner@theobroma-systems.com
Subject: Re: [PATCH v6 13/17] arm64:ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it
Date: Fri, 13 Nov 2015 16:34:10 +0100
Message-ID: <3810107.ZiMyX4Iloo@wuerfel>
User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; )
In-Reply-To: <mvm4mgrxrbt.fsf@hawking.suse.de>
References: <1446507046-24604-1-git-send-email-ynorov@caviumnetworks.com> <16446627.b0Lo936ZJj@wuerfel> <mvm4mgrxrbt.fsf@hawking.suse.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 7Bit
Content-Type: text/plain; charset="us-ascii"
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1155
Lines: 33

On Thursday 12 November 2015 14:47:18 Andreas Schwab wrote:
> Arnd Bergmann <arnd@arndb.de> writes:
> 
> > On Thursday 12 November 2015 10:44:55 Andreas Schwab wrote:
> >> Arnd Bergmann <arnd@arndb.de> writes:
> >> 
> >> > What do you mean with 32-bit off_t?
> >> 
> >> An ABI with 32-bit off_t, ie. all currently implemented 32-bit ABIs.
> >> 
> >> > Do you mean that glibc emulates a 32-bit off_t on top of the 64-bit
> >> > __kernel_loff_t?
> >> 
> >> Glibc is bridging the user-space ABI to the kernel ABI.
> >
> > Ok, but why?
> 
> That's how the ABI is defined right now.  I didn't make that up.

Ok, I guess it will remain a mystery then.

Should we perhaps define __ARCH_WANT_SYSCALL_OFF_T for the unistd.h
file then, so we provide both the off_t and the loff_t based syscalls?

That would avoid the extra wrapper in glibc when using a 32-bit
off_t if that is the preferred mode for user space.

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