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From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 6/6] arm/imx6q: add suspend/resume support
Date: Fri, 9 Sep 2011 09:15:20 +0100	[thread overview]
Message-ID: <20110909081520.GE14953@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20110909073247.GD31581@S2100-06.ap.freescale.net>

On Fri, Sep 09, 2011 at 03:32:48PM +0800, Shawn Guo wrote:
> > Now to the physical act of enabling the L2 cache.  The L2 cache control
> > registers are subject to security restrictions when running in non-secure
> > mode, needing platform specific SMC calls to reprogram the cache.  Generic
> > code is unable to do this.
>
> I could be very possibly wrong here.  But isn't the core in secure mode
> upon reset?  Do we really have to reprogram L2 through SMC calls there?

It probably will be, but the core won't be running the resume function
directly on reset.  (No ARM CPU does this - not even the pre-security
ones.  They've traditionally run the boot loader first.)

Take a moment to think about this in terms of security of data stored on
the secure side (where there maybe private keys stored.)

The kernel runs in the non-secure side of the partition.  If it were to be
entered on resume in secure mode, it could access those keys.  That would
be a really great security hole, which would make the whole thing pointless.

What would happen is the secure monitor ROM code gets control first, just
like it does at normal boot time on secure devices.  Eventually, the kernel
will gain control but only after the secure monitor has switched to
non-secure mode.

  reply	other threads:[~2011-09-09  8:15 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-06  9:58 [PATCH 0/6] add initial imx6q support Shawn Guo
2011-09-06  9:58 ` [PATCH 1/6] arm/imx6q: add device tree source Shawn Guo
2011-09-06 18:31   ` Arnd Bergmann
2011-09-07 11:16     ` Shawn Guo
2011-09-06  9:58 ` [PATCH 2/6] arm/imx6q: add core definitions and low-level debug uart Shawn Guo
2011-09-06 18:39   ` Arnd Bergmann
2011-09-07  8:50     ` Shawn Guo
2011-09-06 20:25   ` Uwe Kleine-König
2011-09-07 11:00     ` Shawn Guo
2011-09-07 12:36       ` Uwe Kleine-König
2011-09-07 14:23         ` Russell King - ARM Linux
2011-09-07 15:36           ` Nicolas Pitre
2011-09-08 14:56             ` Arnd Bergmann
2011-09-09 17:28               ` Tony Lindgren
2011-09-12  2:30         ` Shawn Guo
2011-09-12  7:41           ` Uwe Kleine-König
2011-09-12  8:43             ` Shawn Guo
2011-09-12  8:44       ` Sascha Hauer
2011-09-12 11:36         ` Shawn Guo
2011-09-12 14:14         ` Russell King - ARM Linux
2011-09-17 11:59           ` Russell King - ARM Linux
2011-09-15  1:24     ` Shawn Guo
2011-09-06  9:58 ` [PATCH 3/6] arm/imx6q: add core drivers clock, gpc, mmdc and src Shawn Guo
2011-09-06 19:14   ` Arnd Bergmann
2011-09-07  6:05     ` Shawn Guo
2011-09-07  7:56       ` Arnd Bergmann
2011-09-12 16:12         ` Shawn Guo
2011-09-12 19:40           ` Grant Likely
2011-09-12 20:28             ` Arnd Bergmann
2011-09-12 21:04               ` Grant Likely
2011-09-13  0:07             ` Shawn Guo
2011-09-07 12:43       ` Barry Song
2011-09-08  6:48         ` Shawn Guo
2011-09-11  2:28           ` Barry Song
2011-09-12 19:16           ` Grant Likely
2011-09-12  9:46   ` Sascha Hauer
2011-09-12 11:49     ` Shawn Guo
2011-09-12 12:36       ` Uwe Kleine-König
2011-09-12 12:40         ` Arnd Bergmann
2011-09-12 14:27           ` Shawn Guo
2011-09-15  1:26             ` Shawn Guo
2011-09-06  9:58 ` [PATCH 4/6] arm/imx6q: add smp and cpu hotplug support Shawn Guo
2011-09-06 18:53   ` Arnd Bergmann
2011-09-07  4:41     ` Shawn Guo
2011-09-07  5:08       ` Shilimkar, Santosh
2011-09-07  7:46         ` Shawn Guo
2011-09-06  9:58 ` [PATCH 5/6] arm/imx6q: add device tree machine support Shawn Guo
2011-09-06 18:55   ` Arnd Bergmann
2011-09-07  3:07     ` Shawn Guo
2011-09-07  7:26       ` Arnd Bergmann
2011-09-06  9:58 ` [PATCH 6/6] arm/imx6q: add suspend/resume support Shawn Guo
2011-09-06 18:56   ` Arnd Bergmann
2011-09-07 13:50   ` Barry Song
2011-09-08  6:23     ` Shawn Guo
2011-09-08  7:47       ` Russell King - ARM Linux
2011-09-08 15:22         ` Shawn Guo
2011-09-08 16:24           ` Russell King - ARM Linux
2011-09-08 17:09             ` Lorenzo Pieralisi
2011-09-09  7:40               ` Shawn Guo
2011-09-09  6:31             ` Barry Song
2011-09-09  7:32             ` Shawn Guo
2011-09-09  8:15               ` Russell King - ARM Linux [this message]
2011-09-09 10:15                 ` Shawn Guo
2011-09-09 18:47                   ` Russell King - ARM Linux
2011-09-06 18:28 ` [PATCH 0/6] add initial imx6q support Arnd Bergmann
2011-09-06 19:42   ` Uwe Kleine-König
2011-09-07  2:55     ` Shawn Guo
2011-09-07  9:39       ` Arnd Bergmann
2011-09-07  2:51   ` Shawn Guo

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