From: Segher Boessenkool <segher@kernel.crashing.org>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: eh_frame confusion
Date: Mon, 2 Mar 2020 06:44:42 -0600 [thread overview]
Message-ID: <20200302124442.GI22482@gate.crashing.org> (raw)
In-Reply-To: <3b00b45f-74b5-13e3-9a98-c3d6b3bb7286@rasmusvillemoes.dk>
On Mon, Mar 02, 2020 at 11:56:05AM +0100, Rasmus Villemoes wrote:
> I'm building a ppc32 kernel, and noticed that after upgrading from gcc-7
> to gcc-8 all object files now end up having .eh_frame section.
Since GCC 8, we enable -fasynchronous-unwind-tables by default for
PowerPC. See https://gcc.gnu.org/r259298 .
> For
> vmlinux, that's not a problem, because they all get discarded in
> arch/powerpc/kernel/vmlinux.lds.S . However, they stick around in
> modules, which doesn't seem to be useful - given that everything worked
> just fine with gcc-7, and I don't see anything in the module loader that
> handles .eh_frame.
It is useful for debugging. Not many people debug the kernel like this,
of course.
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>
Subject: Re: eh_frame confusion
Date: Mon, 2 Mar 2020 06:44:42 -0600 [thread overview]
Message-ID: <20200302124442.GI22482@gate.crashing.org> (raw)
In-Reply-To: <3b00b45f-74b5-13e3-9a98-c3d6b3bb7286@rasmusvillemoes.dk>
On Mon, Mar 02, 2020 at 11:56:05AM +0100, Rasmus Villemoes wrote:
> I'm building a ppc32 kernel, and noticed that after upgrading from gcc-7
> to gcc-8 all object files now end up having .eh_frame section.
Since GCC 8, we enable -fasynchronous-unwind-tables by default for
PowerPC. See https://gcc.gnu.org/r259298 .
> For
> vmlinux, that's not a problem, because they all get discarded in
> arch/powerpc/kernel/vmlinux.lds.S . However, they stick around in
> modules, which doesn't seem to be useful - given that everything worked
> just fine with gcc-7, and I don't see anything in the module loader that
> handles .eh_frame.
It is useful for debugging. Not many people debug the kernel like this,
of course.
Segher
next prev parent reply other threads:[~2020-03-02 12:44 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-02 10:56 eh_frame confusion Rasmus Villemoes
2020-03-02 12:44 ` Segher Boessenkool [this message]
2020-03-02 12:44 ` Segher Boessenkool
2020-03-02 17:17 ` Naveen N. Rao
2020-03-02 17:17 ` Naveen N. Rao
2020-03-02 17:09 ` Naveen N. Rao
2020-03-02 17:32 ` Naveen N. Rao
2020-03-03 9:50 ` Rasmus Villemoes
2020-03-05 12:47 ` Naveen N. Rao
2020-03-05 12:47 ` Naveen N. Rao
2020-03-03 10:28 ` Michael Ellerman
2020-03-03 10:28 ` Michael Ellerman
2020-03-05 12:41 ` Naveen N. Rao
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