From: Kyle McMartin <kyle@infradead.org>
To: linuxppc-dev@ozlabs.org
Cc: kyle@redhat.com, aoliva@redhat.com, linux-kernel@vger.kernel.org,
roland@redhat.com
Subject: [PATCH/RFC] powerpc: avoid generating .eh_frame sections with gcc-4.4
Date: Tue, 24 Feb 2009 01:51:12 -0500 [thread overview]
Message-ID: <20090224065112.GA6690@bombadil.infradead.org> (raw)
From: Kyle McMartin <kyle@redhat.com>
On ppc64 (at least) gcc-4.4 is defaulting to generating .eh_frame
sections, which are, for the kernel, fairly pointless. Additionally, on
ppc64 this generates a relocation format which the kernel module loader
does not currently support (R_PPC64_REL32.)
Alexandre Oliva verifies that -fno-dwarf2-cfi-asm prevents this
.eh_frame section from being generated.
These seem to be used for unwinding, but it doesn't look like we
currently use them anywhere. (In fact, we explicitly dump them in the
x86_64 linker script.)
If these .eh_frame sections are eventually used, adding a per-arch
CONFIG_WANT_UNWIND check would be trivial.
(This was reported against Fedora, which appears to be the only distro
doing any building against gcc-4.4 at present: RH bz#486545.)
Signed-off-by: Kyle McMartin <kyle@redhat.com>
Cc: roland@redhat.com
Cc: aoliva@redhat.com
---
diff --git a/Makefile b/Makefile
index df6ce3e..d66a512 100644
--- a/Makefile
+++ b/Makefile
@@ -566,6 +566,11 @@ KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
# disable pointer signed / unsigned warnings in gcc 4.0
KBUILD_CFLAGS += $(call cc-option,-Wno-pointer-sign,)
+# gcc-4.4 defaults to generating .eh_frame sections, but we aren't
+# interested in those currently. additionally, it causes issues on some
+# architectures.
+KBUILD_CFLAGS += $(call cc-option,-fno-dwarf2-cfi-asm)
+
# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
# But warn user when we do so
warn-assign = \
next reply other threads:[~2009-02-24 6:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-24 6:51 Kyle McMartin [this message]
2009-02-24 8:40 ` [PATCH/RFC] powerpc: avoid generating .eh_frame sections with gcc-4.4 Sam Ravnborg
2009-02-24 11:25 ` Alexandre Oliva
2009-02-24 17:48 ` Kyle McMartin
2009-02-24 23:36 ` Roland McGrath
2009-02-25 5:47 ` Sam Ravnborg
2009-02-25 5:46 ` Kyle McMartin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20090224065112.GA6690@bombadil.infradead.org \
--to=kyle@infradead.org \
--cc=aoliva@redhat.com \
--cc=kyle@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@ozlabs.org \
--cc=roland@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).