From: nyushchenko@dev.rtsoft.ru (Nikita Yushchenko)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case
Date: Tue, 24 Nov 2015 18:05:37 +0300 [thread overview]
Message-ID: <56547CC1.6000009@dev.rtsoft.ru> (raw)
In-Reply-To: <5654799E.5080903@dev.rtsoft.ru>
> I'm still trying to understand what is going on, and my printk()s show
> that this is not entirely true.
>
> When smp_init() is entered on mainline om imx6s, cpu_possible_mask and
> cpu_present_mask both contain two cpus. These get initialized in
> arm_dt_init_cpu_maps() and stay unmodified since then.
>
> But cpu_online() returns 1 for cpu0 and 0 from cpu1 - thus it is
> cpu_online() check, not possible_mask or present_mask, that prevents
> cpu1 initialization attempt.
Sorry was too quick to type.
cpu_online(0) is true and cpu_online(1) is false.
It is natural, since cpu0 is already running.
Thus cpu_up(1) is entered!
WARNING: multiple messages have this Message-ID (diff)
From: Nikita Yushchenko <nyushchenko@dev.rtsoft.ru>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>,
kuznetsovg@dev.rtsoft.ru, Ian Campbell <ian.campbell@citrix.com>,
Mason <slash.tmp@free.fr>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Will Deacon <will.deacon@arm.com>,
Paul Kocialkowski <contact@paulk.fr>,
linux-kernel@vger.kernel.org, Pavel Machek <pavel@ucw.cz>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case
Date: Tue, 24 Nov 2015 18:05:37 +0300 [thread overview]
Message-ID: <56547CC1.6000009@dev.rtsoft.ru> (raw)
In-Reply-To: <5654799E.5080903@dev.rtsoft.ru>
> I'm still trying to understand what is going on, and my printk()s show
> that this is not entirely true.
>
> When smp_init() is entered on mainline om imx6s, cpu_possible_mask and
> cpu_present_mask both contain two cpus. These get initialized in
> arm_dt_init_cpu_maps() and stay unmodified since then.
>
> But cpu_online() returns 1 for cpu0 and 0 from cpu1 - thus it is
> cpu_online() check, not possible_mask or present_mask, that prevents
> cpu1 initialization attempt.
Sorry was too quick to type.
cpu_online(0) is true and cpu_online(1) is false.
It is natural, since cpu0 is already running.
Thus cpu_up(1) is entered!
next prev parent reply other threads:[~2015-11-24 15:05 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-23 11:59 [RFC/PATCH] arm: do not skip SMP init calls on SMP_ON_UP case nyushchenko at dev.rtsoft.ru
2015-11-23 11:59 ` nyushchenko
2015-11-23 12:03 ` Russell King - ARM Linux
2015-11-23 12:03 ` Russell King - ARM Linux
2015-11-23 12:06 ` Nikita Yushchenko
2015-11-23 12:06 ` Nikita Yushchenko
2015-11-23 12:12 ` Russell King - ARM Linux
2015-11-23 12:12 ` Russell King - ARM Linux
2015-11-23 12:19 ` Russell King - ARM Linux
2015-11-23 12:19 ` Russell King - ARM Linux
2015-11-23 12:46 ` Nikita Yushchenko
2015-11-23 12:46 ` Nikita Yushchenko
2015-11-23 12:32 ` Vladimir Murzin
2015-11-23 12:32 ` Vladimir Murzin
2015-11-23 12:42 ` Nikita Yushchenko
2015-11-23 12:42 ` Nikita Yushchenko
2015-11-23 12:47 ` Nikita Yushchenko
2015-11-23 12:47 ` Nikita Yushchenko
2015-11-23 13:04 ` Russell King - ARM Linux
2015-11-23 13:04 ` Russell King - ARM Linux
2015-11-24 14:52 ` Nikita Yushchenko
2015-11-24 14:52 ` Nikita Yushchenko
2015-11-24 15:05 ` Nikita Yushchenko [this message]
2015-11-24 15:05 ` Nikita Yushchenko
2015-11-24 15:28 ` Nikita Yushchenko
2015-11-24 15:28 ` Nikita Yushchenko
2015-11-24 15:33 ` Russell King - ARM Linux
2015-11-24 15:33 ` Russell King - ARM Linux
2015-11-28 11:13 ` Nikita Yushchenko
2015-11-28 11:13 ` Nikita Yushchenko
2015-11-30 8:25 ` Nikita Yushchenko
2015-11-30 8:25 ` Nikita Yushchenko
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