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From: Florian Weimer <fw@deneb.enyo.de>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	"H . Peter Anvin" <hpa@zytor.com>, Paul Turner <pjt@google.com>,
	linux-api@vger.kernel.org,
	Christian Brauner <christian.brauner@ubuntu.com>,
	carlos@redhat.com
Subject: Re: [RFC PATCH] rseq: x86: implement abort-at-ip extension
Date: Fri, 07 Jan 2022 20:31:24 +0100	[thread overview]
Message-ID: <87a6g7ny0j.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <20220107170302.8325-1-mathieu.desnoyers@efficios.com> (Mathieu Desnoyers's message of "Fri, 7 Jan 2022 12:03:02 -0500")

* Mathieu Desnoyers:

> Allow rseq critical section abort handlers to optionally figure out at
> which instruction pointer the rseq critical section was aborted.
>
> This allows implementing rseq critical sections containing loops, in
> which case the commit side-effect cannot be the last instruction. This
> is useful to implement adaptative mutexes aware of preemption in
> user-space. (see [1])

Could you write the program counter to the rseq area instead?  This
would avoid discussing which register to clobber.

Thanks,
Florian

  reply	other threads:[~2022-01-07 19:38 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-07 17:03 [RFC PATCH] rseq: x86: implement abort-at-ip extension Mathieu Desnoyers
2022-01-07 19:31 ` Florian Weimer [this message]
2022-01-07 19:48   ` Mathieu Desnoyers
2022-01-07 21:27     ` Mathieu Desnoyers
2022-01-07 22:27       ` David Laight
2022-01-08  1:08         ` Mathieu Desnoyers
2022-01-08  1:33           ` Mathieu Desnoyers
2022-01-08  1:33           ` Mathieu Desnoyers
2022-01-12 15:16     ` Florian Weimer
2022-01-12 15:26       ` Mathieu Desnoyers
2022-01-12 15:38       ` Peter Zijlstra
2022-01-12 16:00         ` Florian Weimer
2022-01-12 16:38           ` Mathieu Desnoyers
2022-01-12 21:00             ` Florian Weimer
2022-01-12 21:24               ` Mathieu Desnoyers

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