[Buildroot] [PATCHv2] linux: may fail to boot for binutils 2.29+ even without armv7m

Arnout Vandecappelle arnout at mind.be
Mon Jun 4 22:10:30 UTC 2018



On 01-06-18 20:01, Yann E. MORIN wrote:
> Commit f13477b (linux: config.in: add comment for Arm Cortex-M) added a
> comment so that the user that the linux kernel may miscompile with
> binutils 2.29+, when the target is an armv7m CPU.
> 
> However, the real trigger is a compilation in thumb2 mode, which happens
> to be the only option for armv7m CPUs.
> 
> We can't know whether the kernel will be built in arm or thumb2 mode,
> though, because we do not have that information: it is only available in
> the Linux' .config file, which we don;t have access to at the time we
> run our menuconfig.
> 
> So, relax the conditions under which the comment is made, so that it
> appears as soon as binutils are >= 2.29 (i.e. not 2.28, which is the
> oldest we support) for ARM CPUs.
> 
> Signed-off-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
> Cc: Christophe Priouzeau <christophe.priouzeau at st.com>
> Cc: Laurent GONZALEZ <br22 at gezedo.com>
> Cc: Peter Korsgaard <peter at korsgaard.com>
> Cc: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
> Cc: Arnout Vandecappelle <arnout at mind.be>
> 
> ---
> Changes v1 -> v2:
>   - only applicable to ARM CPUs.  (Peter)
> ---
>  linux/Config.in | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/linux/Config.in b/linux/Config.in
> index bffb52fd18..c29b1f6c88 100644
> --- a/linux/Config.in
> +++ b/linux/Config.in
> @@ -9,7 +9,7 @@ config BR2_LINUX_KERNEL
>  if BR2_LINUX_KERNEL
>  
>  comment "Linux kernel may fail to boot with binutils >= 2.29"
> -	depends on BR2_ARM_CPU_ARMV7M
> +	depends on BR2_arm || BR2_armeb

 I have a bit of a problem with this patch. IMO it's rather unlikely that people
build the kernel in THUMB mode on non-M CPUs. But now we're always showing this
warning. I think it will confuse a number of people, and I don't think it's very
likely that it will actually help anyone.

 Regards,
 Arnout

>  	depends on !BR2_BINUTILS_VERSION_2_28_X
>  
>  # Packages that need to have a kernel with support for loadable modules,
> 

-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
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