Commit fe3955cb authored by David Woodhouse's avatar David Woodhouse Committed by Benjamin Herrenschmidt
Browse files

powerpc: Enable ARCH_USE_BUILTIN_BSWAP 



By using the compiler intrinsics instead of hand-crafted opaque inline
assembler for byte-swapping, we let the compiler see what's actually
happening and it gets to use lwbrx/stwbrx instructions instead of a
normal load/store coupled with a sequence of rlwimi instructions to
move bits around.

Compiled-tested only. It gave a code size reduction of almost 4% for
ext2, and more like 2.5% for ext3/ext4.

Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
Acked-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent e49f1e20

arch/powerpc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -144,6 +144,7 @@ config PPC 
	select HAVE_MOD_ARCH_SPECIFIC

	select MODULES_USE_ELF_RELA

	select CLONE_BACKWARDS

	select ARCH_USE_BUILTIN_BSWAP



config EARLY_PRINTK

	bool

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