From: Florian Weimer <fweimer@redhat.com>
To: Chris Kennelly <ckennelly@google.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Paul Turner <pjt@google.com>, Peter Oskolkov <posk@posk.io>,
libc-alpha@sourceware.org <libc-alpha@sourceware.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: Aligning tcmalloc with glibc 2.35 rseq ABI
Date: Tue, 01 Feb 2022 21:39:16 +0100 [thread overview]
Message-ID: <87mtja1fuz.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <CAEE+ybn_Cp1-T=2uB7xJqU2gEU-PxzsaV5jqCOupNp2cx_bK-Q@mail.gmail.com> (Chris Kennelly's message of "Tue, 1 Feb 2022 15:33:15 -0500")
* Chris Kennelly:
> Thanks for the heads up.
>
> I did have a question about whether the new protocol would introduce
> an extra memory reference while initializing a critical section.
>
> * With initial-exec TLS, I can directly reference __rseq_abi.
> * With the new ABI, I might need to ask glibc for the address of the
> registered rseq structure in its thread data.
You can write __rseq_offset to a static/hidden variable in an ELF
constructor, and then use pretty much the same assembler sequences as
for initial-exec TLS on most architectures.
Thanks,
Florian
next prev parent reply other threads:[~2022-02-01 20:39 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-01 14:58 Mathieu Desnoyers
2022-02-01 20:33 ` Chris Kennelly
2022-02-01 20:39 ` Florian Weimer [this message]
2022-02-02 8:41 ` Florian Weimer
2022-02-02 11:36 ` Mathieu Desnoyers
2022-02-02 13:08 ` Mathieu Desnoyers
2022-02-02 15:01 ` Florian Weimer
2022-02-02 17:31 ` Carlos O'Donell
2022-02-02 22:28 ` Carlos O'Donell
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