From 1c38976334c0efce1b285369a6037f205e196299 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 28 May 2018 06:08:34 +0000 Subject: [PATCH] powerpc/Makefile: set -mcpu=860 flag for the 8xx When compiled with GCC 8.1, vmlinux is significantly bigger than with GCC 4.8. When looking at the generated code with objdump, we notice that all functions and loops when a 16 bytes alignment. This significantly increases the size of the kernel. It is pointless and even counterproductive as on the 8xx 'nop' also consumes one clock cycle. Size of vmlinux with GCC 4.8: text data bss dec hex filename 5801948 1626076 457796 7885820 7853fc vmlinux Size of vmlinux with GCC 8.1: text data bss dec hex filename 6764592 1630652 456476 8851720 871108 vmlinux Size of vmlinux with GCC 8.1 and this patch: text data bss dec hex filename 6331544 1631756 456476 8419776 8079c0 vmlinux Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman --- arch/powerpc/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 6faf1d6..9b52e42 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -181,6 +181,7 @@ CFLAGS-$(CONFIG_POWER6_CPU) += $(call cc-option,-mcpu=power6) CFLAGS-$(CONFIG_POWER7_CPU) += $(call cc-option,-mcpu=power7) CFLAGS-$(CONFIG_POWER8_CPU) += $(call cc-option,-mcpu=power8) CFLAGS-$(CONFIG_POWER9_CPU) += $(call cc-option,-mcpu=power9) +CFLAGS-$(CONFIG_PPC_8xx) += $(call cc-option,-mcpu=860) # Altivec option not allowed with e500mc64 in GCC. ifeq ($(CONFIG_ALTIVEC),y) -- 2.7.4