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 27RETHUNK_RUSTFLAGS := -Zfunction-return=thunk-extern 28RETPOLINE_CFLAGS += $(RETHUNK_CFLAGS) 29RETPOLINE_RUSTFLAGS += $(RETHUNK_RUSTFLAGS) 30endif 31 32export RETHUNK_CFLAGS 33export RETHUNK_RUSTFLAGS 34export RETPOLINE_CFLAGS 35export RETPOLINE_RUSTFLAGS 36export RETPOLINE_VDSO_CFLAGS 37 38# For gcc stack alignment is specified with -mpreferred-stack-boundary, 39# clang has the option -mstack-alignment for that purpose. 40ifneq ($(call cc-option, -mpreferred-stack-boundary=4),) 41 cc_stack_align4 := -mpreferred-stack-boundary=2 42 cc_stack_align8 := -mpreferred-stack-boundary=3 43else ifneq ($(call cc-option, -mstack-alignment=16),) 44 cc_stack_align4 := -mstack-alignment=4 45 cc_stack_align8 := -mstack-alignment=8 46endif 47 48# How to compile the 16-bit code. Note we always compile for -march=i386; 49# that way we can complain to the user if the CPU is insufficient. 50REALMODE_CFLAGS := -std=gnu11 -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \ 51 -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ 52 -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ 53 -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none) 54 55REALMODE_CFLAGS += -ffreestanding 56REALMODE_CFLAGS += -fno-stack-protector 57REALMODE_CFLAGS += -Wno-address-of-packed-member 58REALMODE_CFLAGS += $(cc_stack_align4) 59REALMODE_CFLAGS += $(CLANG_FLAGS) 60ifdef CONFIG_CC_IS_CLANG 61REALMODE_CFLAGS += -Wno-gnu 62endif 63export REALMODE_CFLAGS 64 65# BITS is used as extension for files which are available in a 32 bit 66# and a 64 bit version to simplify shared Makefiles. 67# e.g.: obj-y += foo_$(BITS).o 68export BITS 69 70# 71# Prevent GCC from generating any FP code by mistake. 72# 73# This must happen before we try the -mpreferred-stack-boundary, see: 74# 75# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 76# 77KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx 78KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json 79KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2 80 81# 82# CFLAGS for compiling floating point code inside the kernel. 83# 84CC_FLAGS_FPU := -msse -msse2 85ifdef CONFIG_CC_IS_GCC 86# Stack alignment mismatch, proceed with caution. 87# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3 88# (8B stack alignment). 89# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 90# 91# The "-msse" in the first argument is there so that the 92# -mpreferred-stack-boundary=3 build error: 93# 94# -mpreferred-stack-boundary=3 is not between 4 and 12 95# 96# can be triggered. Otherwise gcc doesn't complain. 97CC_FLAGS_FPU += -mhard-float 98CC_FLAGS_FPU += $(call cc-option,-msse -mpreferred-stack-boundary=3,-mpreferred-stack-boundary=4) 99endif 100 101ifeq ($(CONFIG_X86_KERNEL_IBT),y) 102# 103# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate 104# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK 105# for jump-tables, as such, disable jump-tables for now. 106# 107# (jump-tables are implicitly disabled by RETPOLINE) 108# 109# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816 110# 111KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables) 112KBUILD_RUSTFLAGS += -Zcf-protection=branch -Zno-jump-tables 113else 114KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) 115endif 116 117ifeq ($(CONFIG_X86_32),y) 118 BITS := 32 119 UTS_MACHINE := i386 120 CHECKFLAGS += -D__i386__ 121 122 KBUILD_AFLAGS += -m32 123 KBUILD_CFLAGS += -m32 124 125 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return 126 127 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built 128 # with nonstandard options 129 KBUILD_CFLAGS += -fno-pic 130 131 # Align the stack to the register width instead of using the default 132 # alignment of 16 bytes. This reduces stack usage and the number of 133 # alignment instructions. 134 KBUILD_CFLAGS += $(cc_stack_align4) 135 136 # CPU-specific tuning. Anything which can be shared with UML should go here. 137 include $(srctree)/arch/x86/Makefile_32.cpu 138 KBUILD_CFLAGS += $(cflags-y) 139 140 # temporary until string.h is fixed 141 KBUILD_CFLAGS += -ffreestanding 142 143 ifeq ($(CONFIG_STACKPROTECTOR),y) 144 ifeq ($(CONFIG_SMP),y) 145 KBUILD_CFLAGS += -mstack-protector-guard-reg=fs \ 146 -mstack-protector-guard-symbol=__ref_stack_chk_guard 147 else 148 KBUILD_CFLAGS += -mstack-protector-guard=global 149 endif 150 endif 151else 152 BITS := 64 153 UTS_MACHINE := x86_64 154 CHECKFLAGS += -D__x86_64__ 155 156 KBUILD_AFLAGS += -m64 157 KBUILD_CFLAGS += -m64 158 159 # Align jump targets to 1 byte, not the default 16 bytes: 160 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 161 162 # Pack loops tightly as well: 163 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 164 165 # Don't autogenerate traditional x87 instructions 166 KBUILD_CFLAGS += -mno-80387 167 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387) 168 169 # By default gcc and clang use a stack alignment of 16 bytes for x86. 170 # However the standard kernel entry on x86-64 leaves the stack on an 171 # 8-byte boundary. If the compiler isn't informed about the actual 172 # alignment it will generate extra alignment instructions for the 173 # default alignment which keep the stack *mis*aligned. 174 # Furthermore an alignment to the register width reduces stack usage 175 # and the number of alignment instructions. 176 KBUILD_CFLAGS += $(cc_stack_align8) 177 178 # Use -mskip-rax-setup if supported. 179 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) 180 181 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) 182 cflags-$(CONFIG_MK8) += -march=k8 183 cflags-$(CONFIG_MPSC) += -march=nocona 184 cflags-$(CONFIG_MCORE2) += -march=core2 185 cflags-$(CONFIG_MATOM) += -march=atom 186 cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic 187 KBUILD_CFLAGS += $(cflags-y) 188 189 rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8 190 rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona 191 rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2 192 rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom 193 rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic 194 KBUILD_RUSTFLAGS += $(rustflags-y) 195 196 KBUILD_CFLAGS += -mno-red-zone 197 KBUILD_CFLAGS += -mcmodel=kernel 198 KBUILD_RUSTFLAGS += -Cno-redzone=y 199 KBUILD_RUSTFLAGS += -Ccode-model=kernel 200endif 201 202# 203# If the function graph tracer is used with mcount instead of fentry, 204# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 205# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 206# 207ifdef CONFIG_FUNCTION_GRAPH_TRACER 208 ifndef CONFIG_HAVE_FENTRY 209 ACCUMULATE_OUTGOING_ARGS := 1 210 endif 211endif 212 213ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 214 # This compiler flag is not supported by Clang: 215 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 216endif 217 218# Workaround for a gcc prelease that unfortunately was shipped in a suse release 219KBUILD_CFLAGS += -Wno-sign-compare 220# 221KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 222 223# Avoid indirect branches in kernel to deal with Spectre 224ifdef CONFIG_MITIGATION_RETPOLINE 225 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 226 KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS) 227 # Additionally, avoid generating expensive indirect jumps which 228 # are subject to retpolines for small number of switch cases. 229 # LLVM turns off jump table generation by default when under 230 # retpoline builds, however, gcc does not for x86. This has 231 # only been fixed starting from gcc stable version 8.4.0 and 232 # onwards, but not for older ones. See gcc bug #86952. 233 ifndef CONFIG_CC_IS_CLANG 234 KBUILD_CFLAGS += -fno-jump-tables 235 endif 236endif 237 238ifdef CONFIG_MITIGATION_SLS 239 KBUILD_CFLAGS += -mharden-sls=all 240endif 241 242ifdef CONFIG_CALL_PADDING 243PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 244KBUILD_CFLAGS += $(PADDING_CFLAGS) 245export PADDING_CFLAGS 246 247PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 248KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS) 249export PADDING_RUSTFLAGS 250endif 251 252KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 253 254ifdef CONFIG_X86_NEED_RELOCS 255LDFLAGS_vmlinux := --emit-relocs --discard-none 256else 257LDFLAGS_vmlinux := 258endif 259 260# 261# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 262# the linker to force 2MB page size regardless of the default page size used 263# by the linker. 264# 265ifdef CONFIG_X86_64 266LDFLAGS_vmlinux += -z max-page-size=0x200000 267endif 268 269 270archscripts: scripts_basic 271 $(Q)$(MAKE) $(build)=arch/x86/tools relocs 272 273### 274# Syscall table generation 275 276archheaders: 277 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 278 279### 280# Kernel objects 281 282libs-y += arch/x86/lib/ 283 284# drivers-y are linked after core-y 285drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 286drivers-$(CONFIG_PCI) += arch/x86/pci/ 287 288# suspend and hibernation support 289drivers-$(CONFIG_PM) += arch/x86/power/ 290 291drivers-$(CONFIG_VIDEO) += arch/x86/video/ 292 293#### 294# boot loader support. Several targets are kept for legacy purposes 295 296boot := arch/x86/boot 297 298BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 299 300PHONY += bzImage $(BOOT_TARGETS) 301 302# Default kernel to build 303all: bzImage 304 305# KBUILD_IMAGE specify target image being built 306KBUILD_IMAGE := $(boot)/bzImage 307 308bzImage: vmlinux 309ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 310 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 311endif 312 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 313 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 314 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 315 316$(BOOT_TARGETS): vmlinux 317 $(Q)$(MAKE) $(build)=$(boot) $@ 318 319PHONY += install 320install: 321 $(call cmd,install) 322 323vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg 324vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg 325vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32.so.dbg 326 327archprepare: checkbin 328checkbin: 329ifdef CONFIG_MITIGATION_RETPOLINE 330ifeq ($(RETPOLINE_CFLAGS),) 331 @echo "You are building kernel with non-retpoline compiler." >&2 332 @echo "Please update your compiler." >&2 333 @false 334endif 335endif 336 337ifdef CONFIG_UNWINDER_ORC 338orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h 339orc_hash_sh := $(srctree)/scripts/orc_hash.sh 340targets += $(orc_hash_h) 341quiet_cmd_orc_hash = GEN $@ 342 cmd_orc_hash = mkdir -p $(dir $@); \ 343 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ 344$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE 345 $(call if_changed,orc_hash) 346archprepare: $(orc_hash_h) 347endif 348 349archclean: 350 $(Q)rm -rf $(objtree)/arch/i386 351 $(Q)rm -rf $(objtree)/arch/x86_64 352 353define archhelp 354 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 355 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 356 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 357 echo ' $$(INSTALL_PATH) and run lilo' 358 echo '' 359 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 360 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 361 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 362 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 363 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 364 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 365 echo ' FDARGS="..." arguments for the booted kernel' 366 echo ' FDINITRD=file initrd for the booted kernel' 367 368endef 369