Messages in this thread Patch in this message | | | Date | Mon, 18 Aug 2008 12:20:41 -0700 | From | Greg KH <> | Subject | [patch 38/49] uml: fix gcc ICEs and unresolved externs |
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2.6.25-stable review patch. If anyone has any objections, please let us know.
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From: Jeff Dike <jdike@addtoit.com>
commit 4f81c5350b44bcc501ab6f8a089b16d064b4d2f6 upstream
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 <jdike@linux.intel.com> Cc: Benny Halevy <bhalevy@panasas.com> Cc: Adrian Bunk <bunk@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/um/Makefile | 1 - arch/um/Makefile-i386 | 7 +++++++ arch/um/Makefile-x86_64 | 3 +++ 3 files changed, 10 insertions(+), 1 deletion(-)
--- a/arch/um/Makefile +++ b/arch/um/Makefile @@ -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 --- a/arch/um/Makefile-i386 +++ b/arch/um/Makefile-i386 @@ -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 += $(cflags-y) --- a/arch/um/Makefile-x86_64 +++ b/arch/um/Makefile-x86_64 @@ -21,3 +21,6 @@ HEADER_ARCH := x86 LINK-$(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) --
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