linux-kernel - Re: [RFC] tty/serial/kgdboc: Add and wire up clear

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]

Date:	Wed, 12 Sep 2012 10:44:20 +0100
From:	Alan Cox <alan@...ux.intel.com>
To:	Anton Vorontsov <anton.vorontsov@...aro.org>
Cc:	Colin Cross <ccross@...roid.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Russell King <linux@....linux.org.uk>,
	Jason Wessel <jason.wessel@...driver.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Arve Hjønnevåg <arve@...roid.com>,
	Brian Swetland <swetland@...gle.com>,
	John Stultz <john.stultz@...aro.org>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linaro-kernel@...ts.linaro.org, patches@...aro.org,
	kernel-team@...roid.com, kgdb-bugreport@...ts.sourceforge.net,
	linux-serial@...r.kernel.org
Subject: Re: [RFC] tty/serial/kgdboc: Add and wire up clear_irqs callback

> Of course, if Alan is OK with this, I'm more than OK too. :-)

It may well be better.

> (But the polling routines would need to clear all interrupts, not
> just rx/tx. For example, if the controller indicated some error, and
> nobody clears it, then we'll start reentering infinitely.)

For a lot of devices and platforms you'd probably mask them instead ?

> 
> > If you use a clear_irqs callback, you can drop characters if
> > one arrives between the last character buffer read and calling
> > clear_irqs.
> 
> Only if we call clear_irqs() after reading the characters, but we do
> it before. So if new characters are available, we will reenter NMI,
> which is OK.

Recursively or not... again you get platform specific magic in places
we don't want.

In the driver poll method for most uarts is going to be at least buried
in what is usually arch specific uarts.

--
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/