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From: mark.rutland@arm.com (Mark Rutland)
To: linux-arm-kernel@lists.infradead.org
Subject: BUG?: kernel does not (re)set irq smp_affinity to reboot_cpu
Date: Mon, 27 Jun 2016 15:54:46 +0100	[thread overview]
Message-ID: <20160627145445.GA29321@leverpostej> (raw)
In-Reply-To: <842a453d-3295-ffbd-f3dd-67baba1692d2@redhat.com>

On Mon, Jun 27, 2016 at 02:53:16PM +0200, Hans de Goede wrote:
> Note this does not mean that all pm_power_off implementations
> are going to be happy with machine_power_off leaving irqs
> enabled, I would esp. expect the efi and psci implementations
> to potentially be unhappy about this. See below for a proposal
> to deal with this.

Neither PSCI nor EFI care either way about interrupts.

PSCI makes synchronous HVC/SMC calls to a higher exception level, and
can be safely called with interrupts enabled or disabled.

EFI's ResetSystem (which backs pm_power_off) can be called with
interrupts enabled or disabled, so long as there is not a clashing call
in progress already (see 7.1 "Runtime Services Rules and Restrictions")
in the EFI 2.6 spec.

Thanks,
Mark.

WARNING: multiple messages have this Message-ID (diff)
From: Mark Rutland <mark.rutland@arm.com>
To: Hans de Goede <hdegoede@redhat.com>
Cc: Russell King - ARM Linux <linux@armlinux.org.uk>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Chen-Yu Tsai <wens@csie.org>,
	Maxime Ripard <maxime.ripard@free-electrons.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: BUG?: kernel does not (re)set irq smp_affinity to reboot_cpu
Date: Mon, 27 Jun 2016 15:54:46 +0100	[thread overview]
Message-ID: <20160627145445.GA29321@leverpostej> (raw)
In-Reply-To: <842a453d-3295-ffbd-f3dd-67baba1692d2@redhat.com>

On Mon, Jun 27, 2016 at 02:53:16PM +0200, Hans de Goede wrote:
> Note this does not mean that all pm_power_off implementations
> are going to be happy with machine_power_off leaving irqs
> enabled, I would esp. expect the efi and psci implementations
> to potentially be unhappy about this. See below for a proposal
> to deal with this.

Neither PSCI nor EFI care either way about interrupts.

PSCI makes synchronous HVC/SMC calls to a higher exception level, and
can be safely called with interrupts enabled or disabled.

EFI's ResetSystem (which backs pm_power_off) can be called with
interrupts enabled or disabled, so long as there is not a clashing call
in progress already (see 7.1 "Runtime Services Rules and Restrictions")
in the EFI 2.6 spec.

Thanks,
Mark.

  parent reply	other threads:[~2016-06-27 14:54 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-26 16:00 BUG?: kernel does not (re)set irq smp_affinity to reboot_cpu Hans de Goede
2016-06-26 16:00 ` Hans de Goede
2016-06-27  9:13 ` Marc Zyngier
2016-06-27  9:13   ` Marc Zyngier
2016-06-27  9:45   ` Russell King - ARM Linux
2016-06-27  9:45     ` Russell King - ARM Linux
2016-06-27 10:55     ` Hans de Goede
2016-06-27 10:55       ` Hans de Goede
2016-06-27 11:31       ` Russell King - ARM Linux
2016-06-27 11:31         ` Russell King - ARM Linux
2016-06-27 11:46         ` Russell King - ARM Linux
2016-06-27 11:46           ` Russell King - ARM Linux
2016-06-27 12:53         ` Hans de Goede
2016-06-27 12:53           ` Hans de Goede
2016-06-27 13:57           ` Russell King - ARM Linux
2016-06-27 13:57             ` Russell King - ARM Linux
2016-06-27 14:37             ` Hans de Goede
2016-06-27 14:37               ` Hans de Goede
2016-06-27 14:54           ` Mark Rutland [this message]
2016-06-27 14:54             ` Mark Rutland

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