From: Daniel Axtens <dja@axtens.net>
To: Bill Wendling <morbo@google.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
clang-built-linux@googlegroups.com
Cc: Bill Wendling <morbo@google.com>
Subject: Re: [PATCH] ppc: add "-z notext" flag to disable diagnostic
Date: Sat, 14 Aug 2021 00:13:11 +1000 [thread overview]
Message-ID: <87sfzde8lk.fsf@linkitivity.dja.id.au> (raw)
In-Reply-To: <20210812204951.1551782-1-morbo@google.com>
Bill Wendling <morbo@google.com> writes:
> The "-z notext" flag disables reporting an error if DT_TEXTREL is set on
> PPC with CONFIG=kdump:
>
> ld.lld: error: can't create dynamic relocation R_PPC64_ADDR64 against
> local symbol in readonly segment; recompile object files with -fPIC
> or pass '-Wl,-z,notext' to allow text relocations in the output
> >>> defined in built-in.a(arch/powerpc/kernel/misc.o)
> >>> referenced by arch/powerpc/kernel/misc.o:(.text+0x20) in archive
> built-in.a
>
> The BFD linker disables this by default (though it's configurable in
> current versions). LLD enables this by default. So we add the flag to
> keep LLD from emitting the error.
You didn't provide a huge amount of context but I was able to reproduce
a similar set of errors with pseries_le_defconfig and
make ARCH=powerpc CROSS_COMPILE=powerpc64-linux-gnu- CC="ccache clang-11" LD=ld.lld-11 AR=llvm-ar-11 -j4 vmlinux
I also checked the manpage, and indeed the system ld does not issue this
warning/error by default.
> ---
> arch/powerpc/Makefile | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index 6505d66f1193..17a9fbf9b789 100644
> --- a/arch/powerpc/Makefile
> +++ b/arch/powerpc/Makefile
> @@ -122,6 +122,7 @@ endif
>
> LDFLAGS_vmlinux-y := -Bstatic
> LDFLAGS_vmlinux-$(CONFIG_RELOCATABLE) := -pie
> +LDFLAGS_vmlinux-$(CONFIG_RELOCATABLE) += -z notext
Is there any reason this should be gated on CONFIG_RELOCATABLE? (I tried
without it and got different but possibly related linker errors...)
Also, is this behaviour new?
Kind regards,
Daniel
> LDFLAGS_vmlinux := $(LDFLAGS_vmlinux-y)
>
> ifdef CONFIG_PPC64
> --
> 2.33.0.rc1.237.g0d66db33f3-goog
next prev parent reply other threads:[~2021-08-13 14:14 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-12 20:49 [PATCH] ppc: add "-z notext" flag to disable diagnostic Bill Wendling
2021-08-12 20:53 ` Nick Desaulniers
2021-08-13 14:13 ` Daniel Axtens [this message]
2021-08-13 18:24 ` Bill Wendling
2021-08-13 18:59 ` Nick Desaulniers
2021-08-14 11:01 ` Segher Boessenkool
2021-08-14 11:59 ` Michael Ellerman
2021-08-13 20:05 ` Fangrui Song
2021-08-14 12:58 ` Segher Boessenkool
2021-08-14 19:34 ` Fāng-ruì Sòng
2021-08-27 14:40 ` Segher Boessenkool
2021-08-13 20:05 ` [PATCH v2] " Bill Wendling
2021-08-27 13:15 ` Michael Ellerman
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