1# SPDX-License-Identifier: GPL-2.0 2# Unified Makefile for i386 and x86_64 3 4# select defconfig based on actual architecture 5ifeq ($(ARCH),x86) 6 ifeq ($(shell uname -m),x86_64) 7 KBUILD_DEFCONFIG := x86_64_defconfig 8 else 9 KBUILD_DEFCONFIG := i386_defconfig 10 endif 11else 12 KBUILD_DEFCONFIG := $(ARCH)_defconfig 13endif 14 15ifdef CONFIG_CC_IS_GCC 16RETPOLINE_CFLAGS := $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register) 17RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch-cs-prefix) 18RETPOLINE_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register) 19endif 20ifdef CONFIG_CC_IS_CLANG 21RETPOLINE_CFLAGS := -mretpoline-external-thunk 22RETPOLINE_VDSO_CFLAGS := -mretpoline 23endif 24 25ifdef CONFIG_RETHUNK 26RETHUNK_CFLAGS := -mfunction-return=thunk-extern 27RETPOLINE_CFLAGS += $(RETHUNK_CFLAGS) 28endif 29 30export RETPOLINE_CFLAGS 31export RETPOLINE_VDSO_CFLAGS 32 33# For gcc stack alignment is specified with -mpreferred-stack-boundary, 34# clang has the option -mstack-alignment for that purpose. 35ifneq ($(call cc-option, -mpreferred-stack-boundary=4),) 36 cc_stack_align4 := -mpreferred-stack-boundary=2 37 cc_stack_align8 := -mpreferred-stack-boundary=3 38else ifneq ($(call cc-option, -mstack-alignment=16),) 39 cc_stack_align4 := -mstack-alignment=4 40 cc_stack_align8 := -mstack-alignment=8 41endif 42 43# How to compile the 16-bit code. Note we always compile for -march=i386; 44# that way we can complain to the user if the CPU is insufficient. 45REALMODE_CFLAGS := -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \ 46 -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ 47 -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ 48 -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none) 49 50REALMODE_CFLAGS += -ffreestanding 51REALMODE_CFLAGS += -fno-stack-protector 52REALMODE_CFLAGS += -Wno-address-of-packed-member 53REALMODE_CFLAGS += $(cc_stack_align4) 54REALMODE_CFLAGS += $(CLANG_FLAGS) 55export REALMODE_CFLAGS 56 57# BITS is used as extension for files which are available in a 32 bit 58# and a 64 bit version to simplify shared Makefiles. 59# e.g.: obj-y += foo_$(BITS).o 60export BITS 61 62# 63# Prevent GCC from generating any FP code by mistake. 64# 65# This must happen before we try the -mpreferred-stack-boundary, see: 66# 67# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 68# 69KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx 70 71ifeq ($(CONFIG_X86_KERNEL_IBT),y) 72# 73# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate 74# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK 75# for jump-tables, as such, disable jump-tables for now. 76# 77# (jump-tables are implicitly disabled by RETPOLINE) 78# 79# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816 80# 81KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables) 82else 83KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) 84endif 85 86ifeq ($(CONFIG_X86_32),y) 87 BITS := 32 88 UTS_MACHINE := i386 89 CHECKFLAGS += -D__i386__ 90 91 KBUILD_AFLAGS += -m32 92 KBUILD_CFLAGS += -m32 93 94 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return 95 96 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built 97 # with nonstandard options 98 KBUILD_CFLAGS += -fno-pic 99 100 # Align the stack to the register width instead of using the default 101 # alignment of 16 bytes. This reduces stack usage and the number of 102 # alignment instructions. 103 KBUILD_CFLAGS += $(cc_stack_align4) 104 105 # CPU-specific tuning. Anything which can be shared with UML should go here. 106 include $(srctree)/arch/x86/Makefile_32.cpu 107 KBUILD_CFLAGS += $(cflags-y) 108 109 # temporary until string.h is fixed 110 KBUILD_CFLAGS += -ffreestanding 111 112 ifeq ($(CONFIG_STACKPROTECTOR),y) 113 ifeq ($(CONFIG_SMP),y) 114 KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard 115 else 116 KBUILD_CFLAGS += -mstack-protector-guard=global 117 endif 118 endif 119else 120 BITS := 64 121 UTS_MACHINE := x86_64 122 CHECKFLAGS += -D__x86_64__ 123 124 KBUILD_AFLAGS += -m64 125 KBUILD_CFLAGS += -m64 126 127 # Align jump targets to 1 byte, not the default 16 bytes: 128 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 129 130 # Pack loops tightly as well: 131 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 132 133 # Don't autogenerate traditional x87 instructions 134 KBUILD_CFLAGS += -mno-80387 135 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387) 136 137 # By default gcc and clang use a stack alignment of 16 bytes for x86. 138 # However the standard kernel entry on x86-64 leaves the stack on an 139 # 8-byte boundary. If the compiler isn't informed about the actual 140 # alignment it will generate extra alignment instructions for the 141 # default alignment which keep the stack *mis*aligned. 142 # Furthermore an alignment to the register width reduces stack usage 143 # and the number of alignment instructions. 144 KBUILD_CFLAGS += $(cc_stack_align8) 145 146 # Use -mskip-rax-setup if supported. 147 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) 148 149 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) 150 cflags-$(CONFIG_MK8) += -march=k8 151 cflags-$(CONFIG_MPSC) += -march=nocona 152 cflags-$(CONFIG_MCORE2) += -march=core2 153 cflags-$(CONFIG_MATOM) += -march=atom 154 cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic 155 KBUILD_CFLAGS += $(cflags-y) 156 157 KBUILD_CFLAGS += -mno-red-zone 158 KBUILD_CFLAGS += -mcmodel=kernel 159endif 160 161# 162# If the function graph tracer is used with mcount instead of fentry, 163# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 164# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 165# 166ifdef CONFIG_FUNCTION_GRAPH_TRACER 167 ifndef CONFIG_HAVE_FENTRY 168 ACCUMULATE_OUTGOING_ARGS := 1 169 endif 170endif 171 172ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 173 # This compiler flag is not supported by Clang: 174 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 175endif 176 177# Workaround for a gcc prelease that unfortunately was shipped in a suse release 178KBUILD_CFLAGS += -Wno-sign-compare 179# 180KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 181 182# Avoid indirect branches in kernel to deal with Spectre 183ifdef CONFIG_RETPOLINE 184 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 185 # Additionally, avoid generating expensive indirect jumps which 186 # are subject to retpolines for small number of switch cases. 187 # clang turns off jump table generation by default when under 188 # retpoline builds, however, gcc does not for x86. This has 189 # only been fixed starting from gcc stable version 8.4.0 and 190 # onwards, but not for older ones. See gcc bug #86952. 191 ifndef CONFIG_CC_IS_CLANG 192 KBUILD_CFLAGS += -fno-jump-tables 193 endif 194endif 195 196ifdef CONFIG_SLS 197 KBUILD_CFLAGS += -mharden-sls=all 198endif 199 200KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 201 202ifdef CONFIG_LTO_CLANG 203ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0) 204KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8) 205endif 206endif 207 208ifdef CONFIG_X86_NEED_RELOCS 209LDFLAGS_vmlinux := --emit-relocs --discard-none 210else 211LDFLAGS_vmlinux := 212endif 213 214# 215# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 216# the linker to force 2MB page size regardless of the default page size used 217# by the linker. 218# 219ifdef CONFIG_X86_64 220LDFLAGS_vmlinux += -z max-page-size=0x200000 221endif 222 223 224archscripts: scripts_basic 225 $(Q)$(MAKE) $(build)=arch/x86/tools relocs 226 227### 228# Syscall table generation 229 230archheaders: 231 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 232 233### 234# Kernel objects 235 236head-y := arch/x86/kernel/head_$(BITS).o 237head-y += arch/x86/kernel/head$(BITS).o 238head-y += arch/x86/kernel/ebda.o 239head-y += arch/x86/kernel/platform-quirks.o 240 241libs-y += arch/x86/lib/ 242 243# drivers-y are linked after core-y 244drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 245drivers-$(CONFIG_PCI) += arch/x86/pci/ 246 247# suspend and hibernation support 248drivers-$(CONFIG_PM) += arch/x86/power/ 249 250drivers-$(CONFIG_FB) += arch/x86/video/ 251 252#### 253# boot loader support. Several targets are kept for legacy purposes 254 255boot := arch/x86/boot 256 257BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 258 259PHONY += bzImage $(BOOT_TARGETS) 260 261# Default kernel to build 262all: bzImage 263 264# KBUILD_IMAGE specify target image being built 265KBUILD_IMAGE := $(boot)/bzImage 266 267bzImage: vmlinux 268ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 269 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 270endif 271 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 272 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 273 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 274 275$(BOOT_TARGETS): vmlinux 276 $(Q)$(MAKE) $(build)=$(boot) $@ 277 278PHONY += install 279install: 280 $(call cmd,install) 281 282PHONY += vdso_install 283vdso_install: 284 $(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@ 285 286archprepare: checkbin 287checkbin: 288ifndef CONFIG_CC_HAS_ASM_GOTO 289 @echo Compiler lacks asm-goto support. 290 @exit 1 291endif 292ifdef CONFIG_RETPOLINE 293ifeq ($(RETPOLINE_CFLAGS),) 294 @echo "You are building kernel with non-retpoline compiler." >&2 295 @echo "Please update your compiler." >&2 296 @false 297endif 298endif 299 300archclean: 301 $(Q)rm -rf $(objtree)/arch/i386 302 $(Q)rm -rf $(objtree)/arch/x86_64 303 304define archhelp 305 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 306 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 307 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 308 echo ' $$(INSTALL_PATH) and run lilo' 309 echo '' 310 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 311 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 312 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 313 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 314 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 315 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 316 echo ' FDARGS="..." arguments for the booted kernel' 317 echo ' FDINITRD=file initrd for the booted kernel' 318 echo '' 319 echo ' kvm_guest.config - Enable Kconfig items for running this kernel as a KVM guest' 320 echo ' xen.config - Enable Kconfig items for running this kernel as a Xen guest' 321 echo ' x86_debug.config - Enable tip tree debugging options for testing' 322 323endef 324