From: Florian Weimer <fweimer@redhat.com>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: carlos <carlos@redhat.com>, Peter Zijlstra <peterz@infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
paulmck <paulmck@linux.ibm.com>,
Boqun Feng <boqun.feng@gmail.com>,
"H. Peter Anvin" <hpa@zytor.com>, Paul Turner <pjt@google.com>,
linux-api <linux-api@vger.kernel.org>,
Christian Brauner <christian.brauner@ubuntu.com>
Subject: Re: [RFC PATCH 2/4] rseq: Allow extending struct rseq
Date: Wed, 15 Jul 2020 16:58:41 +0200 [thread overview]
Message-ID: <87k0z4zuxq.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <1481331967.14276.1594824846736.JavaMail.zimbra@efficios.com> (Mathieu Desnoyers's message of "Wed, 15 Jul 2020 10:54:06 -0400 (EDT)")
* Mathieu Desnoyers:
> ----- On Jul 15, 2020, at 9:42 AM, Florian Weimer fweimer@redhat.com wrote:
>> * Mathieu Desnoyers:
>>
> [...]
>>> How would this allow early-rseq-adopter libraries to interact with
>>> glibc ?
>>
>> Under all extension proposals I've seen so far, early adopters are
>> essentially incompatible with glibc rseq registration. I don't think
>> you can have it both ways.
>
> The basic question I'm not sure about is whether we are allowed to increase
> the size and alignement of __rseq_abi from e.g. glibc 2.32 to glibc 2.33.
With the current mechanism (global TLS data symbol), we can do that
using symbol versioning. That means that we can only do this on a
release boundary, and that it's incompatible with other libraries which
use an interposing unversioned symbol.
Thanks,
Florian
next prev parent reply other threads:[~2020-07-15 14:58 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-14 3:03 [RFC PATCH 0/4] rseq: Introduce extensible struct rseq Mathieu Desnoyers
2020-07-14 3:03 ` [RFC PATCH 1/4] selftests: rseq: Use fixed value as rseq_len parameter Mathieu Desnoyers
2020-07-14 3:03 ` [RFC PATCH 2/4] rseq: Allow extending struct rseq Mathieu Desnoyers
2020-07-14 9:58 ` Florian Weimer
2020-07-14 12:50 ` Mathieu Desnoyers
2020-07-14 13:00 ` Florian Weimer
2020-07-14 13:19 ` Mathieu Desnoyers
2020-07-14 21:30 ` Carlos O'Donell
2020-07-15 13:12 ` Mathieu Desnoyers
2020-07-15 13:22 ` Florian Weimer
2020-07-15 13:31 ` Mathieu Desnoyers
2020-07-15 13:42 ` Florian Weimer
2020-07-15 13:55 ` Christian Brauner
2020-07-15 14:20 ` Mathieu Desnoyers
2020-07-15 14:54 ` Mathieu Desnoyers
2020-07-15 14:58 ` Florian Weimer [this message]
2020-07-15 15:26 ` Mathieu Desnoyers
2020-07-14 17:24 ` Peter Oskolkov
2020-07-14 17:43 ` Mathieu Desnoyers
2020-07-14 18:33 ` Peter Oskolkov
2020-07-15 2:34 ` Chris Kennelly
2020-07-15 6:31 ` Florian Weimer
2020-07-15 10:59 ` Christian Brauner
2020-07-15 14:38 ` Mathieu Desnoyers
2020-07-15 14:50 ` Mathieu Desnoyers
2020-07-15 11:38 ` Christian Brauner
2020-07-15 12:33 ` Christian Brauner
2020-07-15 15:10 ` Mathieu Desnoyers
2020-07-15 15:33 ` Christian Brauner
2020-07-14 3:03 ` [RFC PATCH 3/4] selftests: rseq: define __rseq_abi with extensible size Mathieu Desnoyers
2020-07-14 3:03 ` [RFC PATCH 4/4] selftests: rseq: print rseq extensible size in basic test Mathieu Desnoyers
2020-07-14 20:55 ` [RFC PATCH 0/4] rseq: Introduce extensible struct rseq Carlos O'Donell
2020-07-15 13:02 ` Mathieu Desnoyers
2020-07-16 13:39 ` Carlos O'Donell
2020-07-16 14:45 ` Mathieu Desnoyers
2020-07-15 15:12 ` Florian Weimer
2020-07-15 15:32 ` Mathieu Desnoyers
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