From: David Laight <David.Laight@ACULAB.COM>
To: 'Mathieu Desnoyers' <mathieu.desnoyers@efficios.com>,
Christian Brauner <christian.brauner@ubuntu.com>
Cc: Christian Brauner <brauner@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
paulmck <paulmck@kernel.org>, Boqun Feng <boqun.feng@gmail.com>,
"H. Peter Anvin" <hpa@zytor.com>, Paul Turner <pjt@google.com>,
linux-api <linux-api@vger.kernel.org>,
Florian Weimer <fw@deneb.enyo.de>, carlos <carlos@redhat.com>
Subject: RE: [RFC PATCH v2 1/2] rseq: x86: implement abort-at-ip extension
Date: Wed, 12 Jan 2022 14:58:14 +0000 [thread overview]
Message-ID: <71e7d09733df4a899d12b7ef25198bbc@AcuMS.aculab.com> (raw)
In-Reply-To: <1475639366.24565.1641998849957.JavaMail.zimbra@efficios.com>
> * [*] The openrisc, powerpc64 and x86-64 architectures define a "redzone" as a
> * stack area beyond the stack pointer which can be used by the compiler
> * to store local variables in leaf functions.
I wonder if that is really worth the trouble it causes!
By the time a function is spilling values to stack the cost
of a %sp update is almost certainly noise.
Someone clearly thought it was a 'good idea (tm)'.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2022-01-12 14:58 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-10 17:16 [RFC PATCH v2 1/2] rseq: x86: implement abort-at-ip extension Mathieu Desnoyers
2022-01-10 17:16 ` [RFC PATCH v2 2/2] selftests: rseq: test abort-at-ip extension on x86 Mathieu Desnoyers
2022-01-11 11:05 ` [RFC PATCH v2 1/2] rseq: x86: implement abort-at-ip extension Christian Brauner
2022-01-11 17:43 ` Mathieu Desnoyers
2022-01-12 8:46 ` Christian Brauner
2022-01-12 14:47 ` Mathieu Desnoyers
2022-01-12 14:55 ` Christian Brauner
2022-01-12 14:58 ` David Laight [this message]
2022-01-12 15:05 ` Mathieu Desnoyers
2022-01-12 15:15 ` David Laight
2022-01-12 15:24 ` Mathieu Desnoyers
2022-01-12 15:34 ` Peter Zijlstra
2022-01-12 15:53 ` David Laight
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