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From: Thomas Gleixner <tglx@linutronix.de>
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To: ysionneau@kalrayinc.com, linux-kernel@vger.kernel.org, Peter Zijlstra
 <peterz@infradead.org>
Cc: Jonathan Borne <jborne@kalrayinc.com>, Julian Vetter
 <jvetter@kalrayinc.com>, Yann Sionneau <ysionneau@kalrayinc.com>, Clement
 Leger <clement@clement-leger.fr>, Julien Hascoet <jhascoet@kalrayinc.com>,
 Louis Morhet <lmorhet@kalrayinc.com>, Luc Michel <luc@lmichel.fr>, Marius
 Gligor <mgligor@kalrayinc.com>, bpf@vger.kernel.org
Subject: Re: [RFC PATCH v3 30/37] kvx: Add multi-processor (SMP) support
In-Reply-To: <20240722094226.21602-31-ysionneau@kalrayinc.com>
References: <20240722094226.21602-1-ysionneau@kalrayinc.com>
 <20240722094226.21602-31-ysionneau@kalrayinc.com>
Date: Sat, 27 Jul 2024 16:22:40 +0200
Message-ID: <87ikwqud73.ffs@tglx>
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On Mon, Jul 22 2024 at 11:41, ysionneau@kalrayinc.com wrote:
> +
> +int __cpu_up(unsigned int cpu, struct task_struct *tidle)
> +{
> +	int ret;
> +
> +	__cpu_up_stack_pointer[cpu] = task_stack_page(tidle) + THREAD_SIZE;
> +	__cpu_up_task_pointer[cpu] = tidle;
> +	/* We need to be sure writes are committed */
> +	smp_mb();
> +
> +	if (!smp_ops.smp_boot_secondary) {
> +		pr_err_once("No smp_ops registered: could not bring up secondary CPUs\n");
> +		return -ENOSYS;
> +	}
> +
> +	ret = smp_ops.smp_boot_secondary(cpu);
> +	if (ret == 0) {
> +		/* CPU was successfully started */
> +		while (!cpu_online(cpu))
> +			cpu_relax();

Please use the generic CPU hotplug synchronization mechanisms CONFIG_HOTPLUG_*_SYNC

Thanks,

        tglx