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 | sed -e 's/i.86/i386/'),i386) 7 KBUILD_DEFCONFIG := i386_defconfig 8 else 9 KBUILD_DEFCONFIG := x86_64_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_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register) 18endif 19ifdef CONFIG_CC_IS_CLANG 20RETPOLINE_CFLAGS := -mretpoline-external-thunk 21RETPOLINE_VDSO_CFLAGS := -mretpoline 22endif 23RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch-cs-prefix) 24 25ifdef CONFIG_MITIGATION_RETHUNK 26RETHUNK_CFLAGS := -mfunction-return=thunk-extern 27RETPOLINE_CFLAGS += $(RETHUNK_CFLAGS) 28endif 29 30export RETHUNK_CFLAGS 31export RETPOLINE_CFLAGS 32export RETPOLINE_VDSO_CFLAGS 33 34# For gcc stack alignment is specified with -mpreferred-stack-boundary, 35# clang has the option -mstack-alignment for that purpose. 36ifneq ($(call cc-option, -mpreferred-stack-boundary=4),) 37 cc_stack_align4 := -mpreferred-stack-boundary=2 38 cc_stack_align8 := -mpreferred-stack-boundary=3 39else ifneq ($(call cc-option, -mstack-alignment=16),) 40 cc_stack_align4 := -mstack-alignment=4 41 cc_stack_align8 := -mstack-alignment=8 42endif 43 44# How to compile the 16-bit code. Note we always compile for -march=i386; 45# that way we can complain to the user if the CPU is insufficient. 46REALMODE_CFLAGS := -std=gnu11 -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \ 47 -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ 48 -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ 49 -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none) 50 51REALMODE_CFLAGS += -ffreestanding 52REALMODE_CFLAGS += -fno-stack-protector 53REALMODE_CFLAGS += -Wno-address-of-packed-member 54REALMODE_CFLAGS += $(cc_stack_align4) 55REALMODE_CFLAGS += $(CLANG_FLAGS) 56ifdef CONFIG_CC_IS_CLANG 57REALMODE_CFLAGS += -Wno-gnu 58endif 59export REALMODE_CFLAGS 60 61# BITS is used as extension for files which are available in a 32 bit 62# and a 64 bit version to simplify shared Makefiles. 63# e.g.: obj-y += foo_$(BITS).o 64export BITS 65 66# 67# Prevent GCC from generating any FP code by mistake. 68# 69# This must happen before we try the -mpreferred-stack-boundary, see: 70# 71# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 72# 73KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx 74KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json 75KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2 76 77# 78# CFLAGS for compiling floating point code inside the kernel. 79# 80CC_FLAGS_FPU := -msse -msse2 81ifdef CONFIG_CC_IS_GCC 82# Stack alignment mismatch, proceed with caution. 83# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3 84# (8B stack alignment). 85# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 86# 87# The "-msse" in the first argument is there so that the 88# -mpreferred-stack-boundary=3 build error: 89# 90# -mpreferred-stack-boundary=3 is not between 4 and 12 91# 92# can be triggered. Otherwise gcc doesn't complain. 93CC_FLAGS_FPU += -mhard-float 94CC_FLAGS_FPU += $(call cc-option,-msse -mpreferred-stack-boundary=3,-mpreferred-stack-boundary=4) 95endif 96 97ifeq ($(CONFIG_X86_KERNEL_IBT),y) 98# 99# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate 100# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK 101# for jump-tables, as such, disable jump-tables for now. 102# 103# (jump-tables are implicitly disabled by RETPOLINE) 104# 105# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816 106# 107KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables) 108KBUILD_RUSTFLAGS += -Zcf-protection=branch -Zno-jump-tables 109else 110KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) 111endif 112 113ifeq ($(CONFIG_X86_32),y) 114 BITS := 32 115 UTS_MACHINE := i386 116 CHECKFLAGS += -D__i386__ 117 118 KBUILD_AFLAGS += -m32 119 KBUILD_CFLAGS += -m32 120 121 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return 122 123 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built 124 # with nonstandard options 125 KBUILD_CFLAGS += -fno-pic 126 127 # Align the stack to the register width instead of using the default 128 # alignment of 16 bytes. This reduces stack usage and the number of 129 # alignment instructions. 130 KBUILD_CFLAGS += $(cc_stack_align4) 131 132 # CPU-specific tuning. Anything which can be shared with UML should go here. 133 include $(srctree)/arch/x86/Makefile_32.cpu 134 KBUILD_CFLAGS += $(cflags-y) 135 136 # temporary until string.h is fixed 137 KBUILD_CFLAGS += -ffreestanding 138 139 ifeq ($(CONFIG_STACKPROTECTOR),y) 140 ifeq ($(CONFIG_SMP),y) 141 KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard 142 else 143 KBUILD_CFLAGS += -mstack-protector-guard=global 144 endif 145 endif 146else 147 BITS := 64 148 UTS_MACHINE := x86_64 149 CHECKFLAGS += -D__x86_64__ 150 151 KBUILD_AFLAGS += -m64 152 KBUILD_CFLAGS += -m64 153 154 # Align jump targets to 1 byte, not the default 16 bytes: 155 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 156 157 # Pack loops tightly as well: 158 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 159 160 # Don't autogenerate traditional x87 instructions 161 KBUILD_CFLAGS += -mno-80387 162 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387) 163 164 # By default gcc and clang use a stack alignment of 16 bytes for x86. 165 # However the standard kernel entry on x86-64 leaves the stack on an 166 # 8-byte boundary. If the compiler isn't informed about the actual 167 # alignment it will generate extra alignment instructions for the 168 # default alignment which keep the stack *mis*aligned. 169 # Furthermore an alignment to the register width reduces stack usage 170 # and the number of alignment instructions. 171 KBUILD_CFLAGS += $(cc_stack_align8) 172 173 # Use -mskip-rax-setup if supported. 174 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) 175 176 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) 177 cflags-$(CONFIG_MK8) += -march=k8 178 cflags-$(CONFIG_MPSC) += -march=nocona 179 cflags-$(CONFIG_MCORE2) += -march=core2 180 cflags-$(CONFIG_MATOM) += -march=atom 181 cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic 182 KBUILD_CFLAGS += $(cflags-y) 183 184 rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8 185 rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona 186 rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2 187 rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom 188 rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic 189 KBUILD_RUSTFLAGS += $(rustflags-y) 190 191 KBUILD_CFLAGS += -mno-red-zone 192 KBUILD_CFLAGS += -mcmodel=kernel 193 KBUILD_RUSTFLAGS += -Cno-redzone=y 194 KBUILD_RUSTFLAGS += -Ccode-model=kernel 195endif 196 197# 198# If the function graph tracer is used with mcount instead of fentry, 199# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 200# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 201# 202ifdef CONFIG_FUNCTION_GRAPH_TRACER 203 ifndef CONFIG_HAVE_FENTRY 204 ACCUMULATE_OUTGOING_ARGS := 1 205 endif 206endif 207 208ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 209 # This compiler flag is not supported by Clang: 210 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 211endif 212 213# Workaround for a gcc prelease that unfortunately was shipped in a suse release 214KBUILD_CFLAGS += -Wno-sign-compare 215# 216KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 217 218# Avoid indirect branches in kernel to deal with Spectre 219ifdef CONFIG_MITIGATION_RETPOLINE 220 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 221 # Additionally, avoid generating expensive indirect jumps which 222 # are subject to retpolines for small number of switch cases. 223 # clang turns off jump table generation by default when under 224 # retpoline builds, however, gcc does not for x86. This has 225 # only been fixed starting from gcc stable version 8.4.0 and 226 # onwards, but not for older ones. See gcc bug #86952. 227 ifndef CONFIG_CC_IS_CLANG 228 KBUILD_CFLAGS += -fno-jump-tables 229 endif 230endif 231 232ifdef CONFIG_MITIGATION_SLS 233 KBUILD_CFLAGS += -mharden-sls=all 234endif 235 236ifdef CONFIG_CALL_PADDING 237PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 238KBUILD_CFLAGS += $(PADDING_CFLAGS) 239export PADDING_CFLAGS 240endif 241 242KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 243 244ifdef CONFIG_X86_NEED_RELOCS 245LDFLAGS_vmlinux := --emit-relocs --discard-none 246else 247LDFLAGS_vmlinux := 248endif 249 250# 251# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 252# the linker to force 2MB page size regardless of the default page size used 253# by the linker. 254# 255ifdef CONFIG_X86_64 256LDFLAGS_vmlinux += -z max-page-size=0x200000 257endif 258 259 260archscripts: scripts_basic 261 $(Q)$(MAKE) $(build)=arch/x86/tools relocs 262 263### 264# Syscall table generation 265 266archheaders: 267 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 268 269### 270# Kernel objects 271 272libs-y += arch/x86/lib/ 273 274# drivers-y are linked after core-y 275drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 276drivers-$(CONFIG_PCI) += arch/x86/pci/ 277 278# suspend and hibernation support 279drivers-$(CONFIG_PM) += arch/x86/power/ 280 281drivers-$(CONFIG_VIDEO) += arch/x86/video/ 282 283#### 284# boot loader support. Several targets are kept for legacy purposes 285 286boot := arch/x86/boot 287 288BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 289 290PHONY += bzImage $(BOOT_TARGETS) 291 292# Default kernel to build 293all: bzImage 294 295# KBUILD_IMAGE specify target image being built 296KBUILD_IMAGE := $(boot)/bzImage 297 298bzImage: vmlinux 299ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 300 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 301endif 302 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 303 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 304 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 305 306$(BOOT_TARGETS): vmlinux 307 $(Q)$(MAKE) $(build)=$(boot) $@ 308 309PHONY += install 310install: 311 $(call cmd,install) 312 313vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg 314vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg 315vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32.so.dbg 316 317archprepare: checkbin 318checkbin: 319ifdef CONFIG_MITIGATION_RETPOLINE 320ifeq ($(RETPOLINE_CFLAGS),) 321 @echo "You are building kernel with non-retpoline compiler." >&2 322 @echo "Please update your compiler." >&2 323 @false 324endif 325endif 326 327ifdef CONFIG_UNWINDER_ORC 328orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h 329orc_hash_sh := $(srctree)/scripts/orc_hash.sh 330targets += $(orc_hash_h) 331quiet_cmd_orc_hash = GEN $@ 332 cmd_orc_hash = mkdir -p $(dir $@); \ 333 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ 334$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE 335 $(call if_changed,orc_hash) 336archprepare: $(orc_hash_h) 337endif 338 339archclean: 340 $(Q)rm -rf $(objtree)/arch/i386 341 $(Q)rm -rf $(objtree)/arch/x86_64 342 343define archhelp 344 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 345 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 346 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 347 echo ' $$(INSTALL_PATH) and run lilo' 348 echo '' 349 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 350 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 351 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 352 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 353 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 354 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 355 echo ' FDARGS="..." arguments for the booted kernel' 356 echo ' FDINITRD=file initrd for the booted kernel' 357 358endef 359