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Re: [RFC PATCH] glibc: Perform rseq(2) registration at nptl init and thread creation
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Szabolcs Nagy <szabolcs dot nagy at arm dot com>
- Cc: Mathieu Desnoyers <mathieu dot desnoyers at efficios dot com>, Carlos O'Donell <carlos at redhat dot com>, Florian Weimer <fweimer at redhat dot com>, <nd at arm dot com>, 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>, <libc-alpha at sourceware dot org>, <linux-kernel at vger dot kernel dot org>, <linux-api at vger dot kernel dot org>
- Date: Wed, 19 Sep 2018 19:49:06 +0000
- Subject: Re: [RFC PATCH] glibc: Perform rseq(2) registration at nptl init and thread creation
- References: <20180919144438.1066-1-mathieu.desnoyers@efficios.com> <c58d4d6e-f22a-f5d9-e23a-5bd72cec1a86@arm.com>
On Wed, 19 Sep 2018, Szabolcs Nagy wrote:
> i don't think there is precedent for exposing tls symbol in glibc
> (e.g. errno is exposed via __errno_location function) so there
> might be issues with this (but i don't have immediate concerns).
There have been suggestions to expose TLS errno - but also suggestions
that use of __errno_location is more efficient, at least in terms of code
size everywhere errno is accessed (for some ABIs, anyway).
The ABI tests have code that would list .tbss symbols as "T" in ABI test
baselines, but no existing ABI baselines use that.
--
Joseph S. Myers
joseph@codesourcery.com