From 8b3b005d675726e38bc504d2e35a991e55819155 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Mon, 9 Dec 2013 15:43:38 -0800 Subject: [PATCH] x86, build: Pass in additional -mno-mmx, -mno-sse options In checkin 5551a34e5aea x86-64, build: Always pass in -mno-sse we unconditionally added -mno-sse to the main build, to keep newer compilers from generating SSE instructions from autovectorization. However, this did not extend to the special environments (arch/x86/boot, arch/x86/boot/compressed, and arch/x86/realmode/rm). Add -mno-sse to the compiler command line for these environments, and add -mno-mmx to all the environments as well, as we don't want a compiler to generate MMX code either. This patch also removes a $(cc-option) call for -m32, since we have long since stopped supporting compilers too old for the -m32 option, and in fact hardcode it in other places in the Makefiles. Reported-by: Kevin B. Smith Cc: Sunil K. Pandey Signed-off-by: H. Peter Anvin Cc: H. J. Lu Link: http://lkml.kernel.org/n/tip-j21wzqv790q834n7yc6g80j1@git.kernel.org Cc: # build fix only --- arch/x86/Makefile | 8 ++++---- arch/x86/boot/Makefile | 6 +++--- arch/x86/boot/compressed/Makefile | 1 + arch/x86/realmode/rm/Makefile | 3 ++- 4 files changed, 10 insertions(+), 8 deletions(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index eda00f9be0cf..57d021507120 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -31,8 +31,8 @@ ifeq ($(CONFIG_X86_32),y) KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return - # Don't autogenerate SSE instructions - KBUILD_CFLAGS += -mno-sse + # Don't autogenerate MMX or SSE instructions + KBUILD_CFLAGS += -mno-mmx -mno-sse # Never want PIC in a 32-bit kernel, prevent breakage with GCC built # with nonstandard options @@ -60,8 +60,8 @@ else KBUILD_AFLAGS += -m64 KBUILD_CFLAGS += -m64 - # Don't autogenerate SSE instructions - KBUILD_CFLAGS += -mno-sse + # Don't autogenerate MMX or SSE instructions + KBUILD_CFLAGS += -mno-mmx -mno-sse # Use -mpreferred-stack-boundary=3 if supported. KBUILD_CFLAGS += $(call cc-option,-mpreferred-stack-boundary=3) diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index dce69a256896..d9c11956fce0 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -53,18 +53,18 @@ $(obj)/cpustr.h: $(obj)/mkcpustr FORCE # How to compile the 16-bit code. Note we always compile for -march=i386, # that way we can complain to the user if the CPU is insufficient. -KBUILD_CFLAGS := $(USERINCLUDE) -g -Os -D_SETUP -D__KERNEL__ \ +KBUILD_CFLAGS := $(USERINCLUDE) -m32 -g -Os -D_SETUP -D__KERNEL__ \ -DDISABLE_BRANCH_PROFILING \ -Wall -Wstrict-prototypes \ -march=i386 -mregparm=3 \ -include $(srctree)/$(src)/code16gcc.h \ -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ + -mno-mmx -mno-sse \ $(call cc-option, -ffreestanding) \ $(call cc-option, -fno-toplevel-reorder,\ - $(call cc-option, -fno-unit-at-a-time)) \ + $(call cc-option, -fno-unit-at-a-time)) \ $(call cc-option, -fno-stack-protector) \ $(call cc-option, -mpreferred-stack-boundary=2) -KBUILD_CFLAGS += $(call cc-option, -m32) KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ GCOV_PROFILE := n diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index dcd90df10ab4..c8a6792e7842 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -13,6 +13,7 @@ KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING cflags-$(CONFIG_X86_32) := -march=i386 cflags-$(CONFIG_X86_64) := -mcmodel=small KBUILD_CFLAGS += $(cflags-y) +KBUILD_CFLAGS += -mno-mmx -mno-sse KBUILD_CFLAGS += $(call cc-option,-ffreestanding) KBUILD_CFLAGS += $(call cc-option,-fno-stack-protector) diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile index 88692871823f..9cac82588cbc 100644 --- a/arch/x86/realmode/rm/Makefile +++ b/arch/x86/realmode/rm/Makefile @@ -73,9 +73,10 @@ KBUILD_CFLAGS := $(LINUXINCLUDE) -m32 -g -Os -D_SETUP -D__KERNEL__ -D_WAKEUP \ -march=i386 -mregparm=3 \ -include $(srctree)/$(src)/../../boot/code16gcc.h \ -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ + -mno-mmx -mno-sse \ $(call cc-option, -ffreestanding) \ $(call cc-option, -fno-toplevel-reorder,\ - $(call cc-option, -fno-unit-at-a-time)) \ + $(call cc-option, -fno-unit-at-a-time)) \ $(call cc-option, -fno-stack-protector) \ $(call cc-option, -mpreferred-stack-boundary=2) KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ -- 2.34.1