linux-kernel - Re: [PATCH 1/2] PRUSS UIO driver support

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: <alpine.LFD.2.00.1102181713480.2701@localhost6.localdomain6>
Date:	Fri, 18 Feb 2011 17:15:09 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Arnd Bergmann <arnd@...db.de>
cc:	linux-arm-kernel@...ts.infradead.org,
	Pratheesh Gangadhar <pratheesh@...com>,
	davinci-linux-open-source@...ux.davincidsp.com, gregkh@...e.de,
	amit.chatterjee@...com, "Hans J. Koch" <hjk@...sjkoch.de>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] PRUSS UIO driver support

On Fri, 18 Feb 2011, Arnd Bergmann wrote:
> On Friday 18 February 2011, Pratheesh Gangadhar wrote:
> > Signed-off-by: Pratheesh Gangadhar <pratheesh@...com>
> > +static irqreturn_t pruss_handler(int irq, struct uio_info *dev_info)
> > +{
> > +	return IRQ_HANDLED;
> > +}
> 
> An empty interrupt handler is rather pointless. I guess you really
> notify user space when the interrupt handler gets called, as this
> is the main point of a UIO driver as far as I understand it.

The UIO core code does this for you when the driver handler returns
IRQ_HANDLED, but the empty handler raises a different questions:

Is the interrupt edge triggerd or how do you avoid an irq storm here?
Usually UIO drivers are requested to mask the interrupt in the device
itself.

Thanks,

	tglx

--
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/