Makefile.um
# SPDX-License-Identifier: GPL-2.0
core-y += arch/x86/crypto/
#
# Disable SSE and other FP/SIMD instructions to match normal x86
#
KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
ifeq ($(CONFIG_X86_32),y)
START := 0x8048000
KBUILD_LDFLAGS += -m elf_i386
ELF_ARCH := i386
ELF_FORMAT := elf32-i386
CHECKFLAGS += -D__i386__
KBUILD_CFLAGS += $(call cc-option,-m32)
KBUILD_AFLAGS += $(call cc-option,-m32)
LINK-y += $(call cc-option,-m32)
LDS_EXTRA := -Ui386
export LDS_EXTRA
# First of all, tune CFLAGS for the specific CPU. This actually sets cflags-y.
include $(srctree)/arch/x86/Makefile_32.cpu
# prevent gcc from keeping the stack 16 byte aligned. Taken from i386.
cflags-y += $(call cc-option,-mpreferred-stack-boundary=2)
# Prevent sprintf in nfsd from being converted to strcpy and resulting in
# an unresolved reference.
cflags-y += -ffreestanding
KBUILD_CFLAGS += $(cflags-y)
else
START := 0x60000000
KBUILD_CFLAGS += -fno-builtin -m64
CHECKFLAGS += -m64 -D__x86_64__
KBUILD_AFLAGS += -m64
KBUILD_LDFLAGS += -m elf_x86_64
KBUILD_CPPFLAGS += -m64
ELF_ARCH := i386:x86-64
ELF_FORMAT := elf64-x86-64
# Not on all 64-bit distros /lib is a symlink to /lib64. PLD is an example.
LINK-$(CONFIG_LD_SCRIPT_DYN_RPATH) += -Wl,-rpath,/lib64
LINK-y += -m64
endif