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