Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756603AbYGGRik (ORCPT ); Mon, 7 Jul 2008 13:38:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753969AbYGGRib (ORCPT ); Mon, 7 Jul 2008 13:38:31 -0400 Received: from [198.99.130.12] ([198.99.130.12]:56433 "EHLO saraswathi.solana.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754213AbYGGRia (ORCPT ); Mon, 7 Jul 2008 13:38:30 -0400 Date: Mon, 7 Jul 2008 13:36:56 -0400 From: Jeff Dike To: Linus Torvalds , LKML , uml-devel Cc: Benny Halevy , Adrian Bunk , Ingo Molnar , Ulrich Drepper Subject: [PATCH] UML - fix gcc ICEs and unresolved externs Message-ID: <20080707173656.GB7747@c2.user-mode-linux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3218 Lines: 71 [ This patch needs to get into 2.6.26 ] There are various constraints on the use of unit-at-a-time: i386 uses no-unit-at-a-time for pre-4.0 (not 4.3) x86_64 uses unit-at-a-time always Uli reported a crash on x86_64 with gcc 4.1.2 with unit-at-a-time, resulting in commit c0a18111e571138747a98af18b3a2124df56a0d1 Ingo reported a gcc internal error with gcc 4.3 with no-unit-at-a-timem, resulting in 22eecde2f9034764a3fd095eecfa3adfb8ec9a98 Benny Halevy is seeing extern inlines not resolved with gcc 4.3 with no-unit-at-a-time This patch reintroduces unit-at-a-time for gcc >= 4.0, bringing back the possibility of Uli's crash. If that happens, we'll debug it. I started seeing both the internal compiler errors and unresolved inlines on Fedora 9. This patch fixes both problems, without so far reintroducing the crash reported by Uli. Signed-off-by: Jeff Dike --- arch/um/Makefile | 1 - arch/um/Makefile-i386 | 7 +++++++ arch/um/Makefile-x86_64 | 3 +++ 3 files changed, 10 insertions(+), 1 deletion(-) Index: linux-2.6.22/arch/um/Makefile-i386 =================================================================== --- linux-2.6.22.orig/arch/um/Makefile-i386 2008-05-29 11:21:25.000000000 -0400 +++ linux-2.6.22/arch/um/Makefile-i386 2008-07-07 13:11:10.000000000 -0400 @@ -32,4 +32,11 @@ cflags-y += $(call cc-option,-mpreferred # an unresolved reference. cflags-y += -ffreestanding +# Disable unit-at-a-time mode on pre-gcc-4.0 compilers, it makes gcc use +# a lot more stack due to the lack of sharing of stacklots. Also, gcc +# 4.3.0 needs -funit-at-a-time for extern inline functions. +KBUILD_CFLAGS += $(shell if [ $(call cc-version) -lt 0400 ] ; then \ + echo $(call cc-option,-fno-unit-at-a-time); \ + else echo $(call cc-option,-funit-at-a-time); fi ;) + KBUILD_CFLAGS += $(cflags-y) Index: linux-2.6.22/arch/um/Makefile-x86_64 =================================================================== --- linux-2.6.22.orig/arch/um/Makefile-x86_64 2008-05-29 11:21:25.000000000 -0400 +++ linux-2.6.22/arch/um/Makefile-x86_64 2008-06-30 12:21:01.000000000 -0400 @@ -21,3 +21,6 @@ HEADER_ARCH := x86 LINK-$(CONFIG_LD_SCRIPT_DYN) += -Wl,-rpath,/lib64 LINK-y += -m64 + +# Do unit-at-a-time unconditionally on x86_64, following the host +KBUILD_CFLAGS += $(call cc-option,-funit-at-a-time) Index: linux-2.6.22/arch/um/Makefile =================================================================== --- linux-2.6.22.orig/arch/um/Makefile 2008-06-10 11:35:40.000000000 -0400 +++ linux-2.6.22/arch/um/Makefile 2008-07-07 12:54:13.000000000 -0400 @@ -77,7 +77,6 @@ include $(srctree)/$(ARCH_DIR)/Makefile- KERNEL_DEFINES = $(strip -Derrno=kernel_errno -Dsigprocmask=kernel_sigprocmask \ -Dmktime=kernel_mktime $(ARCH_KERNEL_DEFINES)) KBUILD_CFLAGS += $(KERNEL_DEFINES) -KBUILD_CFLAGS += $(call cc-option,-fno-unit-at-a-time,) PHONY += linux -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/