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 percpu_seg := fs 144else 145 BITS := 64 146 UTS_MACHINE := x86_64 147 CHECKFLAGS += -D__x86_64__ 148 149 KBUILD_AFLAGS += -m64 150 KBUILD_CFLAGS += -m64 151 152 # Align jump targets to 1 byte, not the default 16 bytes: 153 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 154 155 # Pack loops tightly as well: 156 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 157 158 # Don't autogenerate traditional x87 instructions 159 KBUILD_CFLAGS += -mno-80387 160 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387) 161 162 # By default gcc and clang use a stack alignment of 16 bytes for x86. 163 # However the standard kernel entry on x86-64 leaves the stack on an 164 # 8-byte boundary. If the compiler isn't informed about the actual 165 # alignment it will generate extra alignment instructions for the 166 # default alignment which keep the stack *mis*aligned. 167 # Furthermore an alignment to the register width reduces stack usage 168 # and the number of alignment instructions. 169 KBUILD_CFLAGS += $(cc_stack_align8) 170 171 # Use -mskip-rax-setup if supported. 172 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) 173 174 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) 175 cflags-$(CONFIG_MK8) += -march=k8 176 cflags-$(CONFIG_MPSC) += -march=nocona 177 cflags-$(CONFIG_MCORE2) += -march=core2 178 cflags-$(CONFIG_MATOM) += -march=atom 179 cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic 180 KBUILD_CFLAGS += $(cflags-y) 181 182 rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8 183 rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona 184 rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2 185 rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom 186 rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic 187 KBUILD_RUSTFLAGS += $(rustflags-y) 188 189 KBUILD_CFLAGS += -mno-red-zone 190 KBUILD_CFLAGS += -mcmodel=kernel 191 KBUILD_RUSTFLAGS += -Cno-redzone=y 192 KBUILD_RUSTFLAGS += -Ccode-model=kernel 193 194 percpu_seg := gs 195endif 196 197ifeq ($(CONFIG_STACKPROTECTOR),y) 198 ifeq ($(CONFIG_SMP),y) 199 KBUILD_CFLAGS += -mstack-protector-guard-reg=$(percpu_seg) 200 KBUILD_CFLAGS += -mstack-protector-guard-symbol=__ref_stack_chk_guard 201 else 202 KBUILD_CFLAGS += -mstack-protector-guard=global 203 endif 204endif 205 206# 207# If the function graph tracer is used with mcount instead of fentry, 208# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 209# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 210# 211ifdef CONFIG_FUNCTION_GRAPH_TRACER 212 ifndef CONFIG_HAVE_FENTRY 213 ACCUMULATE_OUTGOING_ARGS := 1 214 endif 215endif 216 217ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 218 # This compiler flag is not supported by Clang: 219 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 220endif 221 222# Workaround for a gcc prelease that unfortunately was shipped in a suse release 223KBUILD_CFLAGS += -Wno-sign-compare 224# 225KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 226 227# Avoid indirect branches in kernel to deal with Spectre 228ifdef CONFIG_MITIGATION_RETPOLINE 229 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 230 KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS) 231 # Additionally, avoid generating expensive indirect jumps which 232 # are subject to retpolines for small number of switch cases. 233 # LLVM turns off jump table generation by default when under 234 # retpoline builds, however, gcc does not for x86. This has 235 # only been fixed starting from gcc stable version 8.4.0 and 236 # onwards, but not for older ones. See gcc bug #86952. 237 ifndef CONFIG_CC_IS_CLANG 238 KBUILD_CFLAGS += -fno-jump-tables 239 endif 240endif 241 242ifdef CONFIG_MITIGATION_SLS 243 KBUILD_CFLAGS += -mharden-sls=all 244endif 245 246ifdef CONFIG_CALL_PADDING 247PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 248KBUILD_CFLAGS += $(PADDING_CFLAGS) 249export PADDING_CFLAGS 250 251PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 252KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS) 253export PADDING_RUSTFLAGS 254endif 255 256KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 257 258ifdef CONFIG_X86_NEED_RELOCS 259LDFLAGS_vmlinux := --emit-relocs --discard-none 260else 261LDFLAGS_vmlinux := 262endif 263 264# 265# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 266# the linker to force 2MB page size regardless of the default page size used 267# by the linker. 268# 269ifdef CONFIG_X86_64 270LDFLAGS_vmlinux += -z max-page-size=0x200000 271endif 272 273 274archscripts: scripts_basic 275 $(Q)$(MAKE) $(build)=arch/x86/tools relocs 276 277### 278# Syscall table generation 279 280archheaders: 281 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 282 283### 284# Kernel objects 285 286libs-y += arch/x86/lib/ 287 288# drivers-y are linked after core-y 289drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 290drivers-$(CONFIG_PCI) += arch/x86/pci/ 291 292# suspend and hibernation support 293drivers-$(CONFIG_PM) += arch/x86/power/ 294 295drivers-$(CONFIG_VIDEO) += arch/x86/video/ 296 297#### 298# boot loader support. Several targets are kept for legacy purposes 299 300boot := arch/x86/boot 301 302BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 303 304PHONY += bzImage $(BOOT_TARGETS) 305 306# Default kernel to build 307all: bzImage 308 309# KBUILD_IMAGE specify target image being built 310KBUILD_IMAGE := $(boot)/bzImage 311 312bzImage: vmlinux 313ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 314 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 315endif 316 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 317 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 318 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 319 320$(BOOT_TARGETS): vmlinux 321 $(Q)$(MAKE) $(build)=$(boot) $@ 322 323PHONY += install 324install: 325 $(call cmd,install) 326 327vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg 328vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg 329vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32.so.dbg 330 331archprepare: checkbin 332checkbin: 333ifdef CONFIG_MITIGATION_RETPOLINE 334ifeq ($(RETPOLINE_CFLAGS),) 335 @echo "You are building kernel with non-retpoline compiler." >&2 336 @echo "Please update your compiler." >&2 337 @false 338endif 339endif 340 341ifdef CONFIG_UNWINDER_ORC 342orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h 343orc_hash_sh := $(srctree)/scripts/orc_hash.sh 344targets += $(orc_hash_h) 345quiet_cmd_orc_hash = GEN $@ 346 cmd_orc_hash = mkdir -p $(dir $@); \ 347 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ 348$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE 349 $(call if_changed,orc_hash) 350archprepare: $(orc_hash_h) 351endif 352 353archclean: 354 $(Q)rm -rf $(objtree)/arch/i386 355 $(Q)rm -rf $(objtree)/arch/x86_64 356 357define archhelp 358 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 359 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 360 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 361 echo ' $$(INSTALL_PATH) and run lilo' 362 echo '' 363 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 364 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 365 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 366 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 367 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 368 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 369 echo ' FDARGS="..." arguments for the booted kernel' 370 echo ' FDINITRD=file initrd for the booted kernel' 371 372endef 373