Re: [Buildroot] [PATCH] arch/xtensa: xtensa little endian target requires an overlay file

From: "Yann E. MORIN" <yann.morin.1998@free.fr>
To: Romain Naour <romain.naour@gmail.com>
Cc: buildroot@buildroot.org
Subject: Re: [Buildroot] [PATCH] arch/xtensa: xtensa little endian target requires an overlay file
Date: Tue, 6 Sep 2022 17:56:56 +0200	[thread overview]
Message-ID: <20220906155656.GG1585594@scaer> (raw)
In-Reply-To: <20220904200409.3153993-1-romain.naour@gmail.com>

Romain, All,

On 2022-09-04 22:04 +0200, Romain Naour spake thusly:
> Using a custom Xtensa processor configuration select little endian
> by default. But xtensa for little endian requires an xtensa overlay
> file containing a version of xtensa-config.h header for gcc setting
> XCHAL_HAVE_BE to 0.
> 
> When BR2_XTENSA_LITTLE_ENDIAN is selected, we have to check if
> an overlay file is provided. Error out if BR2_XTENSA_OVERLAY_FILE
> is empty.

Well, why don't we always check for an overlay when BR2_XTENSA_CUSTOM=y?

Indeed, whether big or little endian, if the user selects a custom
xtensa configuration, they better provide the overlay for that
configuration, otherwise that does not make sense, and they should be
using BR2_xtensa_fsf=y instead.

So, maybe just this

    diff --git a/arch/arch.mk.xtensa b/arch/arch.mk.xtensa
    index fd410f6bfa..9cf6f45678 100644
    --- a/arch/arch.mk.xtensa
    +++ b/arch/arch.mk.xtensa
    @@ -10,6 +10,9 @@
     #   endif
     ################################################################################
     BR_ARCH_XTENSA_OVERLAY_FILE = $(call qstrip,$(BR2_XTENSA_OVERLAY_FILE))
    +ifeq ($(BR_BUILDING)$(BR2_XTENSA_CUSTOM):$(BR_ARCH_XTENSA_OVERLAY_FILE),yy:)
    +$(error No xtensa overlay file provided. Check your BR2_XTENSA_OVERLAY_FILE setting)
    +endif
     ifneq ($(filter http://% https://% ftp://% scp://%,$(BR_ARCH_XTENSA_OVERLAY_FILE)),)
     ARCH_XTENSA_OVERLAY_URL = $(BR_ARCH_XTENSA_OVERLAY_FILE)
     ARCH_XTENSA_OVERLAY_FILE = $($(PKG)_DL_DIR)/$(notdir $(BR_ARCH_XTENSA_OVERLAY_FILE))

Thoughts?

Regards,
Yann E. MORIN.

> Fixes:
> http://autobuild.buildroot.org/results/f0b/f0ba47d2534aeb3cc2921124aa639ae3aa072b9b
> 
> xtensa-buildroot-linux-uclibc/bin/ld: ldso/ldso/ld-uClibc_so.a(ldso.oS): compiled for a big endian system and target is little endian
> 
> [1] https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=include/xtensa-config.h;hb=2ee5e4300186a92ad73f1a1a64cb918dc76c8d67#l28
> 
> Signed-off-by: Romain Naour <romain.naour@gmail.com>
> Cc: Max Filippov <jcmvbkbc@gmail.com>
> ---
>  arch/arch.mk.xtensa | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/arch.mk.xtensa b/arch/arch.mk.xtensa
> index fd410f6bfa..516d77bf91 100644
> --- a/arch/arch.mk.xtensa
> +++ b/arch/arch.mk.xtensa
> @@ -34,3 +34,11 @@ define arch-xtensa-overlay-extract
>  		$(ARCH_XTENSA_OVERLAY_FILE) | \
>  	$(TAR) --strip-components=1 -C $(1) $(TAR_OPTIONS) - $(2)
>  endef
> +
> +# By default GCC build xtensa for Big Endian. To build for Little Endian a
> +# Xtensa overlay file must be provided.
> +ifeq ($(BR2_XTENSA_LITTLE_ENDIAN),y)
> +ifeq ($(call qstrip,$(BR2_XTENSA_OVERLAY_FILE)),)
> +$(error No xtensa overlay file provided. Check your BR2_XTENSA_OVERLAY_FILE setting)
> +endif
> +endif
> -- 
> 2.34.3
> 
> _______________________________________________
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> buildroot@buildroot.org
> https://lists.buildroot.org/mailman/listinfo/buildroot

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