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Date: Wed, 10 Aug 2016 00:36:58 +1000
From: Nicholas Piggin <npiggin@gmail.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: <linuxppc-dev@ozlabs.org>, Anton Blanchard <anton@samba.org>,
 <imunsie@au.ibm.com>
Subject: Re: [PATCH] powerpc/Makefile: Use cflags-y/aflags-y for setting
 endian options
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On Tue,  9 Aug 2016 22:43:46 +1000
Michael Ellerman <mpe@ellerman.id.au> wrote:

> When we introduced the little endian support, we added the endian flags
> to CC directly using override. I don't know the history of why we did
> that, I suspect no one does.
> 
> Although this mostly works, it has one bug, which is that CROSS32CC
> doesn't get -mbig-endian. That means when the compiler is little endian
> by default and the user is building big endian, vdso32 is incorrectly
> compiled as little endian and the kernel fails to build.
> 
> Instead we can add the endian flags to cflags-y/aflags-y, and then
> append those to KBUILD_CFLAGS/KBUILD_AFLAGS.
> 
> This has the advantage of being 1) less ugly, 2) the documented way of
> adding flags in the arch Makefile and 3) it fixes building vdso32 with a
> LE toolchain.

This seems okay to me.

> 
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> ---
>  arch/powerpc/Makefile | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index ca254546cd05..1934707bf321 100644
> --- a/arch/powerpc/Makefile
> +++ b/arch/powerpc/Makefile
> @@ -66,29 +66,28 @@ endif
>  UTS_MACHINE := $(OLDARCH)
>  
>  ifeq ($(CONFIG_CPU_LITTLE_ENDIAN),y)
> -override CC	+= -mlittle-endian
> -ifneq ($(cc-name),clang)
> -override CC	+= -mno-strict-align
> -endif
> -override AS	+= -mlittle-endian
>  override LD	+= -EL
> -override CROSS32CC += -mlittle-endian
>  override CROSS32AS += -mlittle-endian

Can't we get rid of CROSS32AS? If not, then should it get the
-mbig-endian override?

Thanks,
Nick