[PATCH] iommu/io-pgtable-arm: Add built time dependency

[Jean Delvare]

Hi Will,

On Fri, 20 Feb 2015 19:19:43 +0000, Will Deacon wrote:
> On Fri, Feb 20, 2015 at 06:44:45PM +0000, Jean Delvare wrote:
> > If io-pgtable-arm is an ARM-specific driver then configuration option
> > IOMMU_IO_PGTABLE_LPAE should not be presented to the user by default
> > for non-ARM kernels.
> > 
> > Signed-off-by: Jean Delvare <jdelvare at suse.de>
> > Cc: Will Deacon <will.deacon at arm.com>
> > Cc: Joerg Roedel <joro at 8bytes.org>
> > ---
> >  drivers/iommu/Kconfig |    1 +
> >  1 file changed, 1 insertion(+)
> > 
> > --- linux-3.20-rc0.orig/drivers/iommu/Kconfig	2015-02-20 17:24:46.838955014 +0100
> > +++ linux-3.20-rc0/drivers/iommu/Kconfig	2015-02-20 19:38:45.804582668 +0100
> > @@ -23,6 +23,7 @@ config IOMMU_IO_PGTABLE
> >  config IOMMU_IO_PGTABLE_LPAE
> >  	bool "ARMv7/v8 Long Descriptor Format"
> >  	select IOMMU_IO_PGTABLE
> > +	depends on ARM || COMPILE_TEST
> >  	help
> >  	  Enable support for the ARM long descriptor pagetable format.
> >  	  This allocator supports 4K/2M/1G, 16K/32M and 64K/512M page
> 
> So this code doesn't actually *depend* on any arch code at all. In fact,
> having it built and booted on x86 revealed a couple of bugs that I've
> since fixed. I'd rather let this run everywhere, but if people insist on
> the false dependency, so be it but we should add ARM64 to the mix too.

Oh, I'm not insisting on anything ;-) If the code is useful on other
architectures then just ignore this patch. But if the only point of
using it on other architectures is to reveal bugs which would not have
triggered otherwise, then that's what COMPILE_TEST is there for.

From the option description and help text, it really looks
ARM-specific, so if it is not, the help text at least should be
improved.

Thanks,
-- 
Jean Delvare
SUSE L3 Support