From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Russell King" <linux@arm.linux.org.uk>,
"Jason Wessel" <jason.wessel@windriver.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Alan Cox" <alan@linux.intel.com>,
"Arve Hjønnevåg" <arve@android.com>,
"Colin Cross" <ccross@android.com>,
"Brian Swetland" <swetland@google.com>,
"John Stultz" <john.stultz@linaro.org>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linaro-kernel@lists.linaro.org, patches@linaro.org,
kernel-team@android.com, kgdb-bugreport@lists.sourceforge.net,
linux-serial@vger.kernel.org
Subject: Re: [PATCH 08/14] tty/serial/kgdboc: Add and wire up clear_irqs callback
Date: Mon, 10 Sep 2012 20:19:18 +0100 [thread overview]
Message-ID: <20120910201918.1e3c8fd0@pyramind.ukuu.org.uk> (raw)
In-Reply-To: <20120910175704.GA11392@lizard>
On Mon, 10 Sep 2012 10:57:04 -0700
Anton Vorontsov <anton.vorontsov@linaro.org> wrote:
> On Mon, Sep 10, 2012 at 12:16:24PM +0100, Alan Cox wrote:
> > > serial port, the CPU receives NMI exception, and we fall into KDB
> > > shell. So, it is our "debug console", and it is able to interrupt
> > > (and thus debug) even IRQ handlers themselves.
> >
> > You seem to have an assumption of single core here. What happens if
> > the NMI hits CPU #0 and the serial IRQ hits CPU #1 simultaneously ?
>
> If you can't redirect all serial IRQs to NMI context, e.g. sometimes you get
> NMIs, sometimes IRQs, then your NMI handling is not deterministic, and surely
> this is not supported.
This seems like arch specific magic leaking into the tty code. Surely
this should be buried in the depths of the platform IRQ code ?
Alan
next prev parent reply other threads:[~2012-09-10 19:14 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-10 4:08 [PATCH v5 0/14] KGDB/KDB FIQ (NMI) debugger Anton Vorontsov
2012-09-10 4:11 ` [PATCH 01/14] serial/amba-pl011: fix ages old copy-paste errors Anton Vorontsov
2012-09-10 4:12 ` [PATCH 02/14] drivers/tty/serial/amba-pl0{10,11}.c: use clk_prepare_enable and clk_disable_unprepare Anton Vorontsov
2012-09-10 4:12 ` [PATCH 03/14] kernel/debug: Mask KGDB NMI upon entry Anton Vorontsov
2012-09-10 4:13 ` [PATCH 04/14] kdb: Implement disable_nmi command Anton Vorontsov
2012-09-10 4:13 ` [PATCH 05/14] kdb: Turn KGDB_KDB=n stubs into static inlines Anton Vorontsov
2012-09-10 4:13 ` [PATCH 06/14] tty/serial/core: Introduce poll_init callback Anton Vorontsov
2012-09-10 11:13 ` Alan Cox
2012-09-10 17:57 ` Anton Vorontsov
2012-09-10 19:18 ` Alan Cox
2012-09-10 4:13 ` [PATCH 07/14] tty/serial/amba-pl011: Implement " Anton Vorontsov
2012-09-10 4:13 ` [PATCH 08/14] tty/serial/kgdboc: Add and wire up clear_irqs callback Anton Vorontsov
2012-09-10 11:16 ` Alan Cox
2012-09-10 17:57 ` Anton Vorontsov
2012-09-10 19:19 ` Alan Cox [this message]
2012-09-10 20:13 ` Anton Vorontsov
2012-09-10 4:14 ` [PATCH 09/14] tty/serial/amba-pl011: Implement " Anton Vorontsov
2012-09-10 11:17 ` Alan Cox
2012-09-10 17:56 ` Anton Vorontsov
2012-09-10 4:14 ` [PATCH 10/14] tty/serial: Add kgdb_nmi driver Anton Vorontsov
2012-09-10 11:11 ` Alan Cox
2012-09-10 17:54 ` Anton Vorontsov
2012-09-10 4:14 ` [PATCH 11/14] ARM: Move some macros from entry-armv to entry-header Anton Vorontsov
2012-09-10 4:14 ` [PATCH 12/14] ARM: Add KGDB/KDB FIQ debugger generic code Anton Vorontsov
2012-09-10 4:14 ` [PATCH 13/14] ARM: VIC: Add a couple of low-level FIQ management helpers Anton Vorontsov
2012-09-10 4:14 ` [PATCH 14/14] ARM: versatile: Make able to use UART ports for KGDB FIQ debugger Anton Vorontsov
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