From: David Woodhouse Date: Wed, 19 Dec 2012 15:14:17 +0000 (+0000) Subject: powerpc: Enable ARCH_USE_BUILTIN_BSWAP X-Git-Tag: Ubuntu-5.2.0-15.16~16241^2~75 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=fe3955cb297290b0d5dedf5d2694a7cef455010e;p=mirror_ubuntu-eoan-kernel.git 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: David Woodhouse Acked-by: H. Peter Anvin Signed-off-by: Benjamin Herrenschmidt --- diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 17903f1f356b..684fa6456797 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -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