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From: Nathan Chancellor <natechancellor@gmail.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Russell King <linux@armlinux.org.uk>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Stefan Agner <stefan@agner.ch>,
	Nicolas Pitre <nicolas.pitre@linaro.org>,
	Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH 2/2] ARM: Wrap '--pic-veneer' with ld-option
Date: Wed, 5 Dec 2018 01:06:45 -0700	[thread overview]
Message-ID: <20181205080645.GA11936@flashbox> (raw)
In-Reply-To: <CAKv+Gu-N9j5X4WoFDbQrzeOCfBaNm6ujXe_fAruusE_kWdj8iQ@mail.gmail.com>

On Wed, Dec 05, 2018 at 08:37:05AM +0100, Ard Biesheuvel wrote:
> On Wed, 5 Dec 2018 at 02:42, Nathan Chancellor <natechancellor@gmail.com> wrote:
> >
> > This flag is not supported by lld:
> >
> >     ld.lld: error: unknown argument: --pic-veneer
> >
> > Signed-off-by: Nathan Chancellor <natechancellor@gmail.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?
> 

Hi Ard,

Honestly, I'm not quite sure. I saw your commit that introduced this
flag and I wasn't quite sure what to make of it for lld. What
configuration would I use to verify and what would I check for?

Additionally, I have filed an LLVM bug for the lld developers to
check and see if this is a flag they should support:

https://bugs.llvm.org/show_bug.cgi?id=39886

Thanks for the quick reply,
Nathan

> > ---
> >  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
> >

WARNING: multiple messages have this Message-ID (diff)
From: Nathan Chancellor <natechancellor@gmail.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Russell King <linux@armlinux.org.uk>,
	Stefan Agner <stefan@agner.ch>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 2/2] ARM: Wrap '--pic-veneer' with ld-option
Date: Wed, 5 Dec 2018 01:06:45 -0700	[thread overview]
Message-ID: <20181205080645.GA11936@flashbox> (raw)
In-Reply-To: <CAKv+Gu-N9j5X4WoFDbQrzeOCfBaNm6ujXe_fAruusE_kWdj8iQ@mail.gmail.com>

On Wed, Dec 05, 2018 at 08:37:05AM +0100, Ard Biesheuvel wrote:
> On Wed, 5 Dec 2018 at 02:42, Nathan Chancellor <natechancellor@gmail.com> wrote:
> >
> > This flag is not supported by lld:
> >
> >     ld.lld: error: unknown argument: --pic-veneer
> >
> > Signed-off-by: Nathan Chancellor <natechancellor@gmail.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?
> 

Hi Ard,

Honestly, I'm not quite sure. I saw your commit that introduced this
flag and I wasn't quite sure what to make of it for lld. What
configuration would I use to verify and what would I check for?

Additionally, I have filed an LLVM bug for the lld developers to
check and see if this is a flag they should support:

https://bugs.llvm.org/show_bug.cgi?id=39886

Thanks for the quick reply,
Nathan

> > ---
> >  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
> >

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2018-12-05  8:06 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-05  1:42 [PATCH 1/2] ARM: Remove '-p' from LDFLAGS Nathan Chancellor
2018-12-05  1:42 ` Nathan Chancellor
2018-12-05  1:42 ` [PATCH 2/2] ARM: Wrap '--pic-veneer' with ld-option Nathan Chancellor
2018-12-05  1:42   ` Nathan Chancellor
2018-12-05  7:37   ` Ard Biesheuvel
2018-12-05  7:37     ` Ard Biesheuvel
2018-12-05  8:06     ` Nathan Chancellor [this message]
2018-12-05  8:06       ` Nathan Chancellor
2018-12-05  8:09       ` Ard Biesheuvel
2018-12-05  8:09         ` Ard Biesheuvel
2018-12-05 18:21         ` Nick Desaulniers
2018-12-05 18:21           ` Nick Desaulniers
2018-12-05 19:30           ` Peter Smith
2018-12-05 19:30             ` Peter Smith
2018-12-05 18:36         ` Nathan Chancellor
2018-12-05 18:36           ` Nathan Chancellor
2018-12-05 18:39           ` Ard Biesheuvel
2018-12-05 18:39             ` Ard Biesheuvel
2018-12-05 18:41             ` Nick Desaulniers
2018-12-05 18:41               ` Nick Desaulniers
2018-12-05 22:59               ` Stefan Agner
2018-12-05 22:59                 ` Stefan Agner
2018-12-05 23:19                 ` Nick Desaulniers
2018-12-05 23:19                   ` Nick Desaulniers
2018-12-05 19:45             ` Nathan Chancellor
2018-12-05 21:03               ` Ard Biesheuvel
2018-12-05 21:03                 ` Ard Biesheuvel
2018-12-29 12:27               ` Stefan Agner
2018-12-29 12:27                 ` Stefan Agner
2019-01-07 19:42                 ` Nick Desaulniers
2019-01-07 19:42                   ` Nick Desaulniers
2018-12-05 18:40           ` Nick Desaulniers
2018-12-05 18:40             ` Nick Desaulniers
2018-12-05  7:37 ` [PATCH 1/2] ARM: Remove '-p' from LDFLAGS Ard Biesheuvel
2018-12-05  7:37   ` Ard Biesheuvel
2018-12-05 16:37 ` Nicolas Pitre
2018-12-05 16:37   ` Nicolas Pitre
2018-12-05 17:47 ` Nick Desaulniers
2018-12-05 17:47   ` Nick Desaulniers
2018-12-29 12:49 ` Stefan Agner
2018-12-29 12:49   ` Stefan Agner
2018-12-31 18:12 ` [PATCH v2] " Nathan Chancellor
2018-12-31 18:12   ` Nathan Chancellor
2019-01-05 16:34   ` Nicolas Pitre
2019-01-05 16:34     ` Nicolas Pitre
2019-01-07 19:19     ` Nick Desaulniers
2019-01-07 19:19       ` Nick Desaulniers

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