linux-kernel - Re: [PATCH 2/2] ARM: Wrap '--pic-veneer' with ld-option

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Message-ID: <CAKv+Gu-N9j5X4WoFDbQrzeOCfBaNm6ujXe_fAruusE_kWdj8iQ@mail.gmail.com>
Date:   Wed, 5 Dec 2018 08:37:05 +0100
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Nathan Chancellor <natechancellor@...il.com>
Cc:     Russell King <linux@...linux.org.uk>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Stefan Agner <stefan@...er.ch>,
        Nicolas Pitre <nicolas.pitre@...aro.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Subject: Re: [PATCH 2/2] ARM: Wrap '--pic-veneer' with ld-option

On Wed, 5 Dec 2018 at 02:42, Nathan Chancellor <natechancellor@...il.com> wrote:
>
> This flag is not supported by lld:
>
>     ld.lld: error: unknown argument: --pic-veneer
>
> Signed-off-by: Nathan Chancellor <natechancellor@...il.com>

Hi Nate,

Does this mean ld.lld is guaranteed to produce position independent
veneers if you build kernels that are bigger than the typical range of
a relative branch?

> ---
>  arch/arm/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> index e2a0baf36766..4fab2aa29570 100644
> --- a/arch/arm/Makefile
> +++ b/arch/arm/Makefile
> @@ -10,7 +10,7 @@
>  #
>  # Copyright (C) 1995-2001 by Russell King
>
> -LDFLAGS_vmlinux        := --no-undefined -X --pic-veneer
> +LDFLAGS_vmlinux        := --no-undefined -X $(call ld-option,--pic-veneer)
>  ifeq ($(CONFIG_CPU_ENDIAN_BE8),y)
>  LDFLAGS_vmlinux        += --be8
>  KBUILD_LDFLAGS_MODULE  += --be8
> --
> 2.20.0.rc1
>