[Buildroot] [PATCH v2 4/4] linux: config.in: add comment for Arm Cortex-M

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello,

On Thu, 31 May 2018 12:36:06 +0000, Christophe PRIOUZEAU wrote:
> On 05/31/2018 02:20 PM, Thomas Petazzoni wrote:
> > Hello Christophe,
> >
> > Thanks for coming up with a patch series for this issue.
> >
> > On Thu, 31 May 2018 12:09:42 +0000, Christophe PRIOUZEAU wrote:  
> >> When binutils > 2.28 are selected on Arm Cortex-M cpu,
> >> linux kernel does not boot due to a new implementation
> >> of 'adr pseudo instruction' on binutils.
> >>
> >> Bugzilla thread: https://bugs.busybox.net/show_bug.cgi?id=11051
> >>
> >> Signed-off-by: Christophe Priouzeau <christophe.priouzeau@st.com>
> >> ---
> >> Changes v1 -> v2
> >>   - correct depends on for comment
> >>
> >>   linux/Config.in | 4 ++++
> >>   1 file changed, 4 insertions(+)
> >>
> >> diff --git a/linux/Config.in b/linux/Config.in
> >> index 73a3299..04d4548 100644
> >> --- a/linux/Config.in
> >> +++ b/linux/Config.in
> >> @@ -8,6 +8,10 @@ config BR2_LINUX_KERNEL
> >>   
> >>   if BR2_LINUX_KERNEL
> >>   
> >> +comment "Linux kernel will not boot with binutils >= 2.29"
> >> +	depends on !BR2_ARMV7M  
> > So this comment will never appear on ARMv7M, which is exactly the
> > opposite of what we want. Did you test this ? Did you verify that the
> > comment actually appears when expected ?  
> Ok, I have made a bad copy/paste from the proposition of Arnoult and is
> why the depends of !BR2_ARMV7M are always true (it's not defined), the 
> correct
> tag are "BR2_ARM_CPU_ARMV7M".
> Sorry, I started to send a new series.

This was indeed one problem. But the other problem is that the
condition is inverted, it should be:

	depends on <we are on ARMv7M>

and not:

	depends on !<we are on ARMv7M>

Indeed, we want the comment to be visible when we are on ARMv7M, and
invisible in all other cases.

Please test your change by running menuconfig and making sure that the
comment is visible vs. invisible as expected.

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com