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From: Arnd Bergmann <arnd@arndb.de>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>,
	Mikael Pettersson <mikpelinux@gmail.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@redhat.com>,
	Darren Hart <dvhart@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Dave Martin <Dave.Martin@arm.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 2/2] ARM: futex: make futex_detect_cmpxchg more reliable
Date: Mon, 11 Mar 2019 17:29:56 +0100	[thread overview]
Message-ID: <CAK8P3a0QCgLbXpztUQXAhWLp=ArJUqmtcuXNZUeXZBH+N1QeaA@mail.gmail.com> (raw)
In-Reply-To: <CAKv+Gu8qgsnPV=uWR2jkJ5bsYihekkEvWNuw4whLdLrbBa7gnA@mail.gmail.com>

On Mon, Mar 11, 2019 at 3:36 PM Ard Biesheuvel
<ard.biesheuvel@linaro.org> wrote:
> On Mon, 11 Mar 2019 at 15:34, Arnd Bergmann <arnd@arndb.de> wrote:
> > On Fri, Mar 8, 2019 at 12:56 PM Ard Biesheuvel
> > <ard.biesheuvel@linaro.org> wrote:
> > > On Fri, 8 Mar 2019 at 11:58, Russell King - ARM Linux admin <linux@armlinux.org.uk> wrote:
> > > > On Fri, Mar 08, 2019 at 11:45:21AM +0100, Ard Biesheuvel wrote:
> >
> > My first attempt (before finding the original patch from Mikael Pettersson)
> > was to change the probe to pass '1' as the value instead of '0', that
> > worked fine.
> >
>
> Which probe is that?

diff --git a/kernel/futex.c b/kernel/futex.c
index c3b73b0311bc..19615ad3c4f7 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -3864,7 +3864,7 @@ static void __init futex_detect_cmpxchg(void)
         * implementation, the non-functional ones will return
         * -ENOSYS.
         */
-       if (cmpxchg_futex_value_locked(&curval, NULL, 0, 0) == -EFAULT)
+       if (cmpxchg_futex_value_locked(&curval, NULL, 1, 1) == -EFAULT)
                futex_cmpxchg_enabled = 1;
 #endif
 }

      Arnd

  reply	other threads:[~2019-03-11 16:30 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-07  9:14 [PATCH 1/2] futex: mark futex_detect_cmpxchg() as 'noinline' Arnd Bergmann
2019-03-07  9:14 ` [PATCH 2/2] ARM: futex: make futex_detect_cmpxchg more reliable Arnd Bergmann
2019-03-07 19:39   ` Nick Desaulniers
2019-03-07 23:48     ` Russell King - ARM Linux admin
2019-03-08  0:04       ` Nick Desaulniers
2019-03-08  9:54         ` Russell King - ARM Linux admin
2019-03-08  8:57       ` Ard Biesheuvel
2019-03-08  9:53         ` Russell King - ARM Linux admin
2019-03-08 10:08           ` Ard Biesheuvel
2019-03-08 10:16             ` Ard Biesheuvel
2019-03-08 10:56               ` Russell King - ARM Linux admin
2019-03-08 10:34             ` Russell King - ARM Linux admin
2019-03-08 10:45               ` Ard Biesheuvel
2019-03-08 10:58                 ` Russell King - ARM Linux admin
2019-03-08 11:55                   ` Ard Biesheuvel
2019-03-11 14:34                     ` Arnd Bergmann
2019-03-11 14:36                       ` Ard Biesheuvel
2019-03-11 16:29                         ` Arnd Bergmann [this message]
2019-03-11 16:36                           ` Ard Biesheuvel
2019-03-11 20:58                             ` Arnd Bergmann
2019-03-08 11:55                 ` Dave Martin
2019-03-07 17:19 ` [PATCH 1/2] futex: mark futex_detect_cmpxchg() as 'noinline' Joe Perches
2019-03-07 17:25   ` Russell King - ARM Linux admin
2019-03-07 17:42     ` Joe Perches
2019-03-07 18:07       ` Russell King - ARM Linux admin
2019-03-07 18:12 ` Nick Desaulniers
2019-03-07 18:21   ` Nathan Chancellor
2019-03-07 22:24     ` Arnd Bergmann
2020-12-12 12:26 ` Marco Elver
2020-12-12 20:01   ` Thomas Gleixner
2020-12-14 10:22     ` Marco Elver
2020-12-14 13:15     ` Arnd Bergmann
2020-12-15  6:09       ` Guo Ren
2020-12-15 11:26         ` Arnd Bergmann
2020-12-15 19:38           ` Sam Ravnborg
2020-12-15 23:24             ` Arnd Bergmann
2020-12-17 15:32               ` Andreas Larsson
2020-12-17 16:43                 ` Arnd Bergmann
2020-12-18 11:08                   ` Andreas Larsson
2020-12-17 20:03               ` Sam Ravnborg
2020-12-16 10:07             ` David Laight
2020-12-16 11:40           ` Peter Zijlstra
2020-12-20 15:44           ` Guo Ren
2020-12-20 17:49             ` Arnd Bergmann
2020-12-21  2:58               ` Guo Ren
2021-07-22 20:05     ` Nathan Chancellor
2021-10-25 13:52       ` Arnd Bergmann

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