http://www.mail-archive.com/armedslack@lists.armedslack.org/msg00212.html From d0679c730395d0bde9a46939e7ba255b4ba7dd7c Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 2 Feb 2010 14:40:02 -0800 Subject: [PATCH] kbuild: move -fno-dwarf2-cfi-asm to powerpc only Better dwarf2 unwind information is a good thing, it allows better debugging with kgdb and crash and helps systemtap. Commit 003086497f07f7f1e67c0c295e261740f822b377 ("Build with -fno-dwarf2-cfi-asm") disabled some CFI information globally to work around a module loader bug on powerpc. But this disables the better unwind tables for all architectures, not just powerpc. Move the workaround to powerpc and also add a suitable comment that's it really a workaround. This improves dwarf2 unwind tables on x86 at least. Signed-off-by: Andi Kleen Cc: Kyle McMartin Signed-off-by: Andrew Morton Acked-by: Benjamin Herrenschmidt Signed-off-by: Michal Marek --- Makefile | 3 --- arch/powerpc/Makefile | 5 +++++ 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/Makefile b/Makefile index 03053c6..2e74a68 100644 --- a/Makefile +++ b/Makefile @@ -579,6 +579,9 @@ KBUILD_CFLAGS += $(call cc-option,-Wno-pointer-sign,) # disable invalid "can't wrap" optimizations for signed / pointers KBUILD_CFLAGS += $(call cc-option,-fno-strict-overflow) +# revert to pre-gcc-4.4 behaviour of .eh_frame +KBUILD_CFLAGS += $(call cc-option,-fno-dwarf2-cfi-asm) + # conserve stack if available KBUILD_CFLAGS += $(call cc-option,-fconserve-stack) diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 1a54a3b..42dcd3f 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -112,11 +112,6 @@ KBUILD_CFLAGS += $(call cc-option,-mspe=no) # kernel considerably. KBUILD_CFLAGS += $(call cc-option,-funit-at-a-time) -# FIXME: the module load should be taught about the additional relocs -# generated by this. -# revert to pre-gcc-4.4 behaviour of .eh_frame -KBUILD_CFLAGS += $(call cc-option,-fno-dwarf2-cfi-asm) - # Never use string load/store instructions as they are # often slow when they are implemented at all KBUILD_CFLAGS += -mno-string -- 1.7.3.1