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Date:   Wed, 14 Nov 2018 18:30:27 +0000
From:   Joseph Myers <joseph@codesourcery.com>
To:     Arnd Bergmann <arnd@arndb.de>
CC:     <carlos@redhat.com>, Szabolcs Nagy <Szabolcs.Nagy@arm.com>,
        Dave Martin <Dave.Martin@arm.com>, <dancol@google.com>,
        <nd@arm.com>, Florian Weimer <fweimer@redhat.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Joel Fernandes <joelaf@google.com>,
        Linux API <linux-api@vger.kernel.org>,
        Willy Tarreau <w@1wt.eu>, Vlastimil Babka <vbabka@suse.cz>,
        GNU C Library <libc-alpha@sourceware.org>,
        Firoz Khan <firoz.khan@linaro.org>
Subject: Re: Official Linux system wrapper library?
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On Wed, 14 Nov 2018, Arnd Bergmann wrote:

> Firoz Khan is in the process of doing part of this, by changing the
> in-kernel per-architecture unistd.h and syscall.S files into a
> architecture independent machine-readable format that is used to
> generate the existing files. The format will be similar to what
> we have on arm/s390/x86 in the syscall.tbl files already.

Will this also mean the following are unable to occur in future (both have 
occurred in the past):

* A syscall added to unistd.h for an architecture, but not added to the 
syscall table until sometime later?

* A syscall added to the native syscall table for some ABI (e.g. 32-bit 
x86 or arm) but not added to the corresponding compat syscall table (e.g. 
32-bit x86 binaries running on x86_64, 32-bit arm binaries running on 
arm64) until sometime later?

Avoiding both of those complications is beneficial to libc (as is a third 
thing, avoiding a syscall being added to different architectures in 
different versions).

-- 
Joseph S. Myers
joseph@codesourcery.com