powerpc: Suppress .eh_frame generation

GCC v8 defaults to enabling -fasynchronous-unwind-tables due to
https://gcc.gnu.org/r259298, which results in .eh_frame section being
generated. This results in additional disk usage by the build, as well
as the kernel modules. Since the kernel has no use for this, this
section is discarded.

Add -fno-asynchronous-unwind-tables to KBUILD_CFLAGS to suppress
generation of .eh_frame section. Note that our VDSOs need .eh_frame, but
are not affected by this change since our VDSO code are all in assembly.

Reported-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1ed7cd84a7d1a3180b30c0c60e70eed8bb8b40c3.1583415544.git.naveen.n.rao@linux.vnet.ibm.com
This commit is contained in:
Naveen N. Rao 2020-03-05 20:05:30 +05:30 committed by Michael Ellerman
parent c04868df38
commit ba96301ce9
1 changed files with 3 additions and 0 deletions

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@ -239,6 +239,9 @@ KBUILD_CFLAGS += $(call cc-option,-mno-vsx)
KBUILD_CFLAGS += $(call cc-option,-mno-spe)
KBUILD_CFLAGS += $(call cc-option,-mspe=no)
# Don't emit .eh_frame since we have no use for it
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
# Never use string load/store instructions as they are
# often slow when they are implemented at all
KBUILD_CFLAGS += $(call cc-option,-mno-string)