linux-kernel - Re: [PATCH v3 rcu 08/11] arch/s390: Add ARCH_HAS_NMI_SAFE_THIS_CPU

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 20 Oct 2022 09:23:49 +0200
From:   Heiko Carstens <hca@...ux.ibm.com>
To:     Christian Borntraeger <borntraeger@...ux.ibm.com>
Cc:     "Paul E. McKenney" <paulmck@...nel.org>, rcu@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-team@...com,
        rostedt@...dmis.org, Neeraj Upadhyay <quic_neeraju@...cinc.com>,
        Frederic Weisbecker <frederic@...nel.org>,
        Boqun Feng <boqun.feng@...il.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        John Ogness <john.ogness@...utronix.de>,
        Petr Mladek <pmladek@...e.com>, linux-s390@...r.kernel.org
Subject: Re: [PATCH v3 rcu 08/11] arch/s390: Add
 ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option

On Thu, Oct 20, 2022 at 07:16:44AM +0200, Christian Borntraeger wrote:
> 
> 
> Am 20.10.22 um 00:58 schrieb Paul E. McKenney:
> > The s390 architecture uses either a cmpxchg loop (old systems)
> > or the laa add-to-memory instruction (new systems) to implement
> > this_cpu_add(), both of which are NMI safe.  This means that the old
> > and more-efficient srcu_read_lock() may be used in NMI context, without
> > the need for srcu_read_lock_nmisafe().  Therefore, add the new Kconfig
> > option ARCH_HAS_NMI_SAFE_THIS_CPU_OPS to arch/arm64/Kconfig, which will
> 						s390 ?
> > cause NEED_SRCU_NMI_SAFE to be deselected, thus preserving the current
> > srcu_read_lock() behavior.
> > 
> > Link: https://lore.kernel.org/all/20220910221947.171557773@linutronix.de/
> > 
> > Suggested-by: Neeraj Upadhyay <quic_neeraju@...cinc.com>
> > Suggested-by: Frederic Weisbecker <frederic@...nel.org>
> > Suggested-by: Boqun Feng <boqun.feng@...il.com>
> > Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
...
> > ---
> >   arch/s390/Kconfig | 1 +
> >   1 file changed, 1 insertion(+)

Not sure what Christian was trying to say with his empty reply :)
In any case:
Acked-by: Heiko Carstens <hca@...ux.ibm.com>