linux-kernel - Re: [PATCH] arm: irq: Allow for specification of no preallocated irqs

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] [day] [month] [year] [list]

Date:	Fri, 20 Jan 2012 09:15:57 -0700
From:	Grant Likely <grant.likely@...retlab.ca>
To:	Michael Bohan <mbohan@...eaurora.org>
Cc:	Rob Herring <robherring2@...il.com>, tglx@...utronix.de,
	Russell King <linux@....linux.org.uk>,
	linux-arm-msm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arm: irq: Allow for specification of no preallocated irqs

On Thu, Jan 19, 2012 at 04:29:43PM -0800, Michael Bohan wrote:
> On 1/19/2012 3:04 PM, Rob Herring wrote:
> >No doubt that arch_probe_nr_irqs is doing the wrong thing on ARM, but no
> >pre-allocation is not what we want either. We ultimately want
> >arch_probe_nr_irqs to return NR_IRQS_LEGACY (16) to reserve IRQ0 (aka
> >NO_IRQ) and legacy ISA IRQs. With my series, NR_IRQS is set to
> >NR_IRQS_LEGACY for SPARSE_IRQ. You can accomplish the same thing without
> >that series by setting .nr_irqs to NR_IRQS for non-DT and to
> >NR_IRQS_LEGACY for DT. For platforms to work in single kernel builds,
> >they will need to select SPARSE_IRQ.
> 
> One issue here is that IRQ_BITMAP_BITS is defined as a function of
> NR_IRQS. Currently, there's a hack in place that arbitrarily tacks
> on 8196 bits to the end, giving the max virq supported as 8212 with
> your patches. Unfortunately, the system I'm running on will require
> higher values than that, so this actually breaks me.

Are that many irqs actually going to be in-use at one time?  If not, then the driver should use the irq_domain radix tree reverse map anyway.

g.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/