This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: [RFC PATCH glibc 1/4] glibc: Perform rseq(2) registration at C startup and thread creation (v6)
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Mathieu Desnoyers <mathieu dot desnoyers at efficios dot com>
- Cc: carlos <carlos at redhat dot com>, Florian Weimer <fweimer at redhat dot com>, Szabolcs Nagy <szabolcs dot nagy at arm dot com>, libc-alpha <libc-alpha at sourceware dot org>, Thomas Gleixner <tglx at linutronix dot de>, Ben Maurer <bmaurer at fb dot com>, Peter Zijlstra <peterz at infradead dot org>, "Paul E. McKenney" <paulmck at linux dot vnet dot ibm dot com>, Boqun Feng <boqun dot feng at gmail dot com>, Will Deacon <will dot deacon at arm dot com>, Dave Watson <davejwatson at fb dot com>, Paul Turner <pjt at google dot com>, Rich Felker <dalias at libc dot org>, linux-kernel <linux-kernel at vger dot kernel dot org>, linux-api <linux-api at vger dot kernel dot org>
- Date: Wed, 30 Jan 2019 21:10:07 +0000
- Subject: Re: [RFC PATCH glibc 1/4] glibc: Perform rseq(2) registration at C startup and thread creation (v6)
- References: <20190121213530.23803-1-mathieu.desnoyers@efficios.com> <632671842.3079.1548781059601.JavaMail.zimbra@efficios.com> <alpine.DEB.2.21.1901292153190.24454@digraph.polyomino.org.uk> <596949707.3888.1548812359874.JavaMail.zimbra@efficios.com> <alpine.DEB.2.21.1901300231210.24454@digraph.polyomino.org.uk> <1832200535.4162.1548871426959.JavaMail.zimbra@efficios.com>
On Wed, 30 Jan 2019, Mathieu Desnoyers wrote:
> #if defined (__NR_rseq) && !defined (RSEQ_SIG)
> # error "UAPI headers support rseq system call, but glibc does not define RSEQ_SIG."
> #endif
>
> Would that take care of your concerns ?
That would of course need appropriate conditionals based on the most
recent kernel version for which a given glibc version has been updated, so
that using new kernel headers with an existing glibc release does not make
the build fail (cf. the test of syscall-names.list). And being able to
write such a test only solves one half of the problem - it needs to be
easy to determine what value to put in that header in glibc for an
architecture that's newly gained support in the kernel, *without* needing
any architecture expertise.
--
Joseph S. Myers
joseph@codesourcery.com