From: "Suzuki K. Poulose" <Suzuki.Poulose@arm.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, marc.zyngier@arm.com,
linux-kernel@vger.kernel.org, will.deacon@arm.com,
catalin.marinas@arm.com
Subject: Re: [PATCH v2 2/6] arm64: Move kill_cpu_early to smp.c
Date: Tue, 1 Dec 2015 17:38:54 +0000 [thread overview]
Message-ID: <565DDB2E.2010308@arm.com> (raw)
In-Reply-To: <20151201163138.GA29045@leverpostej>
On 01/12/15 16:31, Mark Rutland wrote:
> For PSCI 0.2+ we can query AFFINITY_INFO to discover whether a CPU is
> whether or not it is in the firmware (i.e. whether or not it is
> potentially in the kernel), so we can certainly query this in some
> cases.
>
> We already do this in the usual hotplug-off case; see cpu_kill.
OK, good to know.
>> Correct, I didn't think about kexec. May be we could indicate the result
>> back (that we are looping in kernel) in secondary_data and that could solve
>> the synchronisation part ?
>
> I think we need to have two flags, a cpu-must-die flag in secondary
> data, and a global stuck-in-the-kernel flag.
>
> The CPU wanting to die could set its cpu-must-die flag, signal the
> completion, then cpu_die(). The CPU awaiting the completion would then
> check cpu-must-die, and if so, cpu_kill() that CPU. If not set, we had a
> successful onlining.
Correct.
>
> We need stuck-in-the-kernel flag to account for CPUs which didn't manage
> to turn the MMU on (which are either in the spin-table, or failed when
> they were individually onlined).
Did you mean to say "turn the MMU off" ?
Cheers
Suzuki
next prev parent reply other threads:[~2015-12-01 17:38 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-01 15:12 [PATCH v2 0/6] arm64: cpufeature: Add sanity check for ASIDBits Suzuki K. Poulose
2015-12-01 15:12 ` [PATCH v2 1/6] arm64: Introduce kill_cpu_early Suzuki K. Poulose
2015-12-01 15:12 ` [PATCH v2 2/6] arm64: Move kill_cpu_early to smp.c Suzuki K. Poulose
2015-12-01 15:28 ` Mark Rutland
2015-12-01 16:07 ` Suzuki K. Poulose
2015-12-01 16:31 ` Mark Rutland
2015-12-01 17:38 ` Suzuki K. Poulose [this message]
2015-12-01 17:52 ` Mark Rutland
2015-12-01 18:10 ` Suzuki K. Poulose
2015-12-01 18:50 ` Mark Rutland
2015-12-03 16:36 ` Suzuki K. Poulose
2015-12-03 17:08 ` Mark Rutland
2015-12-01 15:12 ` [PATCH v2 3/6] arm64: Enable CPU capability verification for !CONFIG_HOTPLUG_CPU Suzuki K. Poulose
2015-12-01 15:12 ` [PATCH v2 4/6] arm64: Add hook for checking early CPU features Suzuki K. Poulose
2015-12-01 15:12 ` [PATCH v2 5/6] arm64: Add helper for extracting ASIDBits Suzuki K. Poulose
2015-12-01 15:12 ` [PATCH v2 6/6] arm64: Ensure the secondary CPUs have safe ASIDBits size Suzuki K. Poulose
2015-12-01 15:15 ` [PATCH v2 0/6] arm64: cpufeature: Add sanity check for ASIDBits Suzuki K. Poulose
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