linux-kernel - Re: [PATCH] drivers/perf: arm-pmu: Handle per-interrupt affinity mask

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20160706103951.GC17925@arm.com>
Date:	Wed, 6 Jul 2016 11:39:52 +0100
From:	Will Deacon <will.deacon@....com>
To:	Marc Zyngier <marc.zyngier@....com>
Cc:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	devicetree@...r.kernel.org, linux-rockchip@...ts.infradead.org,
	Heiko Stuebner <heiko@...ech.de>, cf@...k-chips.com,
	huangtao@...k-chips.com, jay.xu@...k-chips.com,
	Caesar Wang <wxt@...k-chips.com>,
	David Wu <david.wu@...k-chips.com>,
	Brian Norris <briannorris@...omium.org>,
	Mark Rutland <mark.rutland@....com>,
	Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH] drivers/perf: arm-pmu: Handle per-interrupt affinity mask

On Fri, Jul 01, 2016 at 02:21:31PM +0100, Marc Zyngier wrote:
> On a big-little system, PMUs can be wired to CPUs using per CPU
> interrups (PPI). In this case, it is important to make sure that
> the enable/disable do happen on the right set of CPUs.
> 
> So instead of relying on the interrupt-affinity property, we can
> use the actual percpu affinity that DT exposes as part of the
> interrupt specifier. The DT binding is also updated to reflect
> the fact that the interrupt-affinity property shouldn't be used
> in that case.

[...]

> -	/* If we didn't manage to parse anything, claim to support all CPUs */
> -	if (cpumask_weight(&pmu->supported_cpus) == 0)
> -		cpumask_setall(&pmu->supported_cpus);
> +	/* If we didn't manage to parse anything, try the interrupt affinity */
> +	if (cpumask_weight(&pmu->supported_cpus) == 0) {
> +		if (!using_spi) {
> +			/* If using PPIs, check the affinity of the partition */
> +			int irq = platform_get_irq(pdev, 0);
> +			irq_get_percpu_devid_partition(irq,
> +						       &pmu->supported_cpus);

Should we not at least propagate the failure if this returns -EINVAL?

Will