Re: kbuild - introduce support for subdir-ccflags-y

[Kyle Moffett <kyle@moffetthome.net>]

On Sat, Apr 18, 2009 at 2:09 PM, Russell King <rmk+lkml@arm.linux.org.uk> wrote:
> On Sat, Apr 18, 2009 at 05:07:50PM +0200, Ingo Molnar wrote:
>> * Russell King <rmk+lkml@arm.linux.org.uk> wrote:
>> > On Sat, Apr 18, 2009 at 02:51:59PM +0200, Sam Ravnborg wrote:
>> > > The typical use cases are an architecture or a subsystem that
>> > > decide to cover all files with -Werror.
>> > > Today alpha, mips and sparc uses -Werror in almost all their
>> > > Makefile - with subdir-ccflag-y it is now simpler to do so
>> > > as only the top-level directories needs to be covered.
>> >
>> > Hmm, this won't make sense for ARM.  We have things like #warning
>> > and deprecated functions in machine specific headers, and adding
>> > -Werror to the whole of arch/arm/ will result in these causing
>> > builds to fail.
>>
>> This is optional - if you dont want it, you dont set it.
>
> Please read _all_ of my mail, particularly the bit where it talks about
> it being useful for a certain subset.

It's my impression that on x86 it's a config option whether or not to
build with -Werror.  You could do the exact same thing with an
internal inverted-logic CONFIG_ARM_ALLOW_WARNINGS option and make all
the boards triggering warnings "select ARM_ALLOW_WARNINGS".  Then have
a user-visible config option "ARM_USER_ALLOW_WARNINGS" which also
selects the internal option.  That adds some additional kconfig-level
documentation on which subarch combos need some love.

Cheers,
Kyle Moffett