[Buildroot] [PATCH v2 1/1] toolchain/toolchain-buildroot: PPC64(LE) support in musl requires ALTIVEC

[Romain Naour]

Hi Vincent,

Le 31/01/2020 à 16:39, Vincent Fazio a écrit :
> musl currently assumes all PPC64(LE) CPUs support ALTIVEC instructions.
> 
> However, there are exceptions (such as the e5500) for which musl builds
> ultimately generate illegal instructions for the targets.
> 
> Disable musl if the PPC64(LE) CPU does not support ALTIVEC instructions.
> 
> This patch addresses the issues seen here:
>   https://gitlab.com/kubu93/toolchains-builder/-/jobs/418092743
>   https://gitlab.com/kubu93/toolchains-builder/-/jobs/418092744

I reported this issue to the musl mailing list. I'm not sure the e5500 support
will be added in the end.

https://www.openwall.com/lists/musl/2020/02/03/10

> 
> Signed-off-by: Vincent Fazio <vfazio at xes-inc.com>
> ---
>  toolchain/toolchain-buildroot/Config.in | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/toolchain/toolchain-buildroot/Config.in b/toolchain/toolchain-buildroot/Config.in
> index a980f766ac..09a46822c9 100644
> --- a/toolchain/toolchain-buildroot/Config.in
> +++ b/toolchain/toolchain-buildroot/Config.in
> @@ -83,8 +83,10 @@ config BR2_TOOLCHAIN_BUILDROOT_MUSL
>  	bool "musl"
>  	depends on BR2_aarch64	   || BR2_arm   || BR2_armeb   || BR2_i386 || \
>  		   BR2_microblaze  || BR2_mips  || BR2_mipsel  || BR2_mips64 || \
> -		   BR2_mips64el    || BR2_or1k  || BR2_powerpc || BR2_powerpc64 || \
> -		   BR2_powerpc64le || BR2_RISCV_64 || BR2_sh   || BR2_x86_64
> +		   BR2_mips64el    || BR2_or1k  || BR2_powerpc || BR2_RISCV_64 || \
> +		   BR2_sh	   || BR2_x86_64 || \
> +		   ((BR2_powerpc64 || BR2_powerpc64le) && BR2_POWERPC_CPU_HAS_ALTIVEC)
> +		   # musl assumes all PPC64 targets support ALTIVEC instructions

Well, previously the architectures was sorted alphabetically. Please keep it.

You can add the dependency this way:

# musl assumes all PPC64 targets support ALTIVEC instructions
depends on !(BR2_powerpc64 || BR2_powerpc64le) || BR2_POWERPC_CPU_HAS_ALTIVEC

Best regards,
Romain

>  	depends on !BR2_powerpc_SPE # not supported, build breaks
>  	# sh2 nommu is supported by musl, but we don't have support
>  	# for it in Buildroot.
>