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Subject[PATCH] Move -fno-dwarf2-cfi-asm to powerpc only
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 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 <>

Makefile | 3 ---
arch/powerpc/Makefile | 5 +++++
2 files changed, 5 insertions(+), 3 deletions(-)

Index: linux-2.6.33-rc1-ak/Makefile
--- linux-2.6.33-rc1-ak.orig/Makefile
+++ linux-2.6.33-rc1-ak/Makefile
@@ -570,9 +570,6 @@ KBUILD_CFLAGS += $(call cc-option,-Wno-p
# 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)

Index: linux-2.6.33-rc1-ak/arch/powerpc/Makefile
--- linux-2.6.33-rc1-ak.orig/arch/powerpc/Makefile
+++ linux-2.6.33-rc1-ak/arch/powerpc/Makefile
@@ -112,6 +112,11 @@ KBUILD_CFLAGS += $(call cc-option,-mspe=
# 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

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