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From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/2] ARM: cache-l2x0: remove __init annotation from initialization functions
Date: Thu, 15 Sep 2011 09:32:48 +0100	[thread overview]
Message-ID: <20110915083248.GG6267@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20110915013937.GE1488@S2100-06.ap.freescale.net>

On Thu, Sep 15, 2011 at 09:39:39AM +0800, Shawn Guo wrote:
> On Wed, Sep 14, 2011 at 09:42:38AM +0100, Russell King - ARM Linux wrote:
> > I'm unconvinced about the wise-ness of this.  We read-modify-write the
> > auxillary control register, which means some bits are preserved from
> > the initial boot.  If the boot loader sets the L2 cache up for normal
> > boot and not for resume, we'll end up with different L2 cache settings.
> > 
> > We've historically seen this kind of thing with boot loaders over the
> > years, to the point where systems boot at one CPU clock rate but resume
> > at some other CPU clock rate.
> > 
> I would think this is a problem in the kernel.  Kernel initialization
> code should put all these stuff into a known state to ensure boot and
> resume of the kernel do not result in a different state, shouldn't it?

grep the kernel for l2x0_init() and look at the mask and value registers.
Note that any bit set in the mask is preserved from boot time.

  reply	other threads:[~2011-09-15  8:32 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-06  5:48 [PATCH v2 0/2] make reinitialization of ARM core components possible Shawn Guo
2011-09-06  5:48 ` [PATCH v2 1/2] ARM: cache-l2x0: remove __init annotation from initialization functions Shawn Guo
2011-09-06  7:19   ` Linus Walleij
2011-09-12  5:27     ` Shawn Guo
2011-09-14  8:42   ` Russell King - ARM Linux
2011-09-14  8:53     ` Santosh
2011-09-14 19:05       ` Russell King - ARM Linux
2011-09-14  9:59     ` Barry Song
2011-09-15  1:39     ` Shawn Guo
2011-09-15  8:32       ` Russell King - ARM Linux [this message]
2011-09-16  3:24         ` Barry Song
2011-09-17 10:45           ` Russell King - ARM Linux
2011-09-17 14:41             ` Barry Song
2011-09-17 14:56               ` Russell King - ARM Linux
2011-09-19  3:36                 ` Barry Song
2011-09-19  5:33                 ` Barry Song
2011-09-23 20:55                   ` Russell King - ARM Linux
2011-09-26  2:43                     ` Barry Song
2011-09-17 15:14             ` Shawn Guo
2011-09-06  5:48 ` [PATCH v2 2/2] ARM: smp_scu: remove __init annotation from scu_enable() Shawn Guo
2011-09-17  8:32   ` Shawn Guo
2011-09-22 15:04     ` Shawn Guo
2011-09-23 20:49       ` Russell King - ARM Linux
2011-09-24 10:39         ` Shawn Guo
2011-09-24 10:38           ` Russell King - ARM Linux
2011-09-06  6:01 ` [PATCH v2 0/2] make reinitialization of ARM core components possible Santosh
2011-09-06  7:02   ` Santosh
2011-09-12  5:41   ` Shawn Guo
2011-09-14 19:07     ` Russell King - ARM Linux
2011-09-15  1:53       ` Shawn Guo
2011-09-15  8:43         ` Russell King - ARM Linux

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