Enabling runtime P2V by default (Re: [PATCH 3/5] mach-u300: patch physoffset by default)

Russell King - ARM Linux linux at arm.linux.org.uk
Thu Aug 11 04:37:17 EDT 2011


On Thu, Aug 11, 2011 at 11:32:44AM +0300, Baruch Siach wrote:
> Hi Russell,
> 
> On Thu, Aug 11, 2011 at 09:24:13AM +0100, Russell King - ARM Linux wrote:
> > On Wed, Aug 10, 2011 at 10:29:55AM +0100, Russell King - ARM Linux wrote:
> > > On Wed, Aug 10, 2011 at 10:22:06AM +0100, Will Deacon wrote:
> > > > On Wed, Aug 10, 2011 at 10:16:35AM +0100, Russell King - ARM Linux wrote:
> > > > > On Tue, Aug 09, 2011 at 09:41:38PM +0200, Linus Walleij wrote:
> > > > > > From: Linus Walleij <linus.walleij at linaro.org>
> > > > > > 
> > > > > > This works like a charm so I'll just default-select it.
> > > > > 
> > > > > Well, we can remove the EXPERIMENTAL status of this option now.  This
> > > > > raises the question is whether we should now default it to 'y' - I
> > > > > think we should.  Anyone have any objections?
> > > > 
> > > > I've been running with this option enabled for the collection of ARM boards
> > > > I have and the only problem I have encountered was related to u-boot loading
> > > > at the wrong address.
> > > > 
> > > > So I'm all for enabling it by default, especially since it will force out
> > > > any remaining issues for boards where this hasn't been used extensively.
> > > 
> > > Maybe also making the option hidden depending on EXPERT, or even EMBEDDED
> > > would be a good idea too.  I think it falls into at least the same class
> > > as UID16, sysctl, hotplug, printk, etc. which are all EXPERT options.
> > 
> > Right, I'm now committing a patch to hide the option unless EMBEDDED
> > is enabled.  I think this means we should get rid of the 'select
> > ARM_PATCH_PHYS_VIRT' statements from the various platforms, so that
> > folk can optimize away that code if they know what they're doing.
> > 
> > Note: this patch will conflict with the removal of the 16-bit P2V
> > patching, so we need to sort that out.
> > 
> > 8<---------
> > From: Russell King - ARM Linux <linux at arm.linux.org.uk>
> > ARM: enable ARM_PATCH_PHYS_VIRT by default
> > 
> > Enable virtual to physical translation patching by default in all
> > kernels.  Hide the option behind EMBEDDED.
> > 
> > This can still be turned off if people desire, and they know what
> > they're doing, to shrink the size of the kernel to a minimum.
> > 
> > Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
> 
> [snip]
> 
> > +	  Only disable this option if you know what you do not require
> > +	  this feature (eg, building a kernel for a single machine) and
> > +	  you need to shrink the kernel to the minimal size.
> 
> The word 'what' in this statement looks redundant.

Should be 'that'.



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