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| author | Jeff Dike <jdike@addtoit.com> | 2008-08-05 16:14:10 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-08-20 11:15:41 -0700 |
| commit | 54b3dcdfaa010e60a5657d6eea5672d930e575cc (patch) | |
| tree | 240c2ea5cadb242ea30018dcf442964754df03c9 | |
| parent | ec70bce783891791930988bbd137c74dc8b416fc (diff) | |
| download | lwn-54b3dcdfaa010e60a5657d6eea5672d930e575cc.tar.gz lwn-54b3dcdfaa010e60a5657d6eea5672d930e575cc.zip | |
uml: fix gcc ICEs and unresolved externs
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>
| -rw-r--r-- | arch/um/Makefile | 1 | ||||
| -rw-r--r-- | arch/um/Makefile-i386 | 7 | ||||
| -rw-r--r-- | arch/um/Makefile-x86_64 | 3 |
3 files changed, 10 insertions, 1 deletions
diff --git a/arch/um/Makefile b/arch/um/Makefile index dbeab15e7bb7..ca40397017b9 100644 --- a/arch/um/Makefile +++ b/arch/um/Makefile @@ -77,7 +77,6 @@ include $(srctree)/$(ARCH_DIR)/Makefile-os-$(OS) 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 diff --git a/arch/um/Makefile-i386 b/arch/um/Makefile-i386 index 561e373bd850..302cbe504543 100644 --- a/arch/um/Makefile-i386 +++ b/arch/um/Makefile-i386 @@ -32,4 +32,11 @@ cflags-y += $(call cc-option,-mpreferred-stack-boundary=2) # 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 += $(cflags-y) diff --git a/arch/um/Makefile-x86_64 b/arch/um/Makefile-x86_64 index 8ed362f93582..a9cd7e77a7ab 100644 --- a/arch/um/Makefile-x86_64 +++ b/arch/um/Makefile-x86_64 @@ -21,3 +21,6 @@ HEADER_ARCH := x86 LINK-$(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) |