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 += $(call cc-option,-mskip-rax-setup) 173 174 KBUILD_CFLAGS += -march=x86-64 -mtune=generic 175 KBUILD_RUSTFLAGS += -Ctarget-cpu=x86-64 -Ztune-cpu=generic 176 177 KBUILD_CFLAGS += -mno-red-zone 178 KBUILD_CFLAGS += -mcmodel=kernel 179 KBUILD_RUSTFLAGS += -Cno-redzone=y 180 KBUILD_RUSTFLAGS += -Ccode-model=kernel 181 182 percpu_seg := gs 183endif 184 185ifeq ($(CONFIG_STACKPROTECTOR),y) 186 ifeq ($(CONFIG_SMP),y) 187 KBUILD_CFLAGS += -mstack-protector-guard-reg=$(percpu_seg) 188 KBUILD_CFLAGS += -mstack-protector-guard-symbol=__ref_stack_chk_guard 189 else 190 KBUILD_CFLAGS += -mstack-protector-guard=global 191 endif 192endif 193 194# 195# If the function graph tracer is used with mcount instead of fentry, 196# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 197# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 198# 199ifdef CONFIG_FUNCTION_GRAPH_TRACER 200 ifndef CONFIG_HAVE_FENTRY 201 ACCUMULATE_OUTGOING_ARGS := 1 202 endif 203endif 204 205ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 206 # This compiler flag is not supported by Clang: 207 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 208endif 209 210# Workaround for a gcc prelease that unfortunately was shipped in a suse release 211KBUILD_CFLAGS += -Wno-sign-compare 212# 213KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 214 215# Avoid indirect branches in kernel to deal with Spectre 216ifdef CONFIG_MITIGATION_RETPOLINE 217 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 218 KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS) 219 # Additionally, avoid generating expensive indirect jumps which 220 # are subject to retpolines for small number of switch cases. 221 # LLVM turns off jump table generation by default when under 222 # retpoline builds, however, gcc does not for x86. This has 223 # only been fixed starting from gcc stable version 8.4.0 and 224 # onwards, but not for older ones. See gcc bug #86952. 225 ifndef CONFIG_CC_IS_CLANG 226 KBUILD_CFLAGS += -fno-jump-tables 227 endif 228endif 229 230ifdef CONFIG_MITIGATION_SLS 231 KBUILD_CFLAGS += -mharden-sls=all 232endif 233 234ifdef CONFIG_CALL_PADDING 235PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 236KBUILD_CFLAGS += $(PADDING_CFLAGS) 237export PADDING_CFLAGS 238 239PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 240KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS) 241export PADDING_RUSTFLAGS 242endif 243 244KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 245 246ifdef CONFIG_X86_NEED_RELOCS 247LDFLAGS_vmlinux := --emit-relocs --discard-none 248else 249LDFLAGS_vmlinux := 250endif 251 252# 253# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 254# the linker to force 2MB page size regardless of the default page size used 255# by the linker. 256# 257ifdef CONFIG_X86_64 258LDFLAGS_vmlinux += -z max-page-size=0x200000 259endif 260 261 262archscripts: scripts_basic 263 $(Q)$(MAKE) $(build)=arch/x86/tools relocs 264 265### 266# Syscall table generation 267 268archheaders: 269 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 270 271### 272# <asm/cpufeaturemasks.h> header generation 273 274cpufeaturemasks.hdr := arch/x86/include/generated/asm/cpufeaturemasks.h 275cpufeaturemasks.awk := $(srctree)/arch/x86/tools/cpufeaturemasks.awk 276cpufeatures_hdr := $(srctree)/arch/x86/include/asm/cpufeatures.h 277targets += $(cpufeaturemasks.hdr) 278quiet_cmd_gen_featuremasks = GEN $@ 279 cmd_gen_featuremasks = $(AWK) -f $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) > $@ 280 281$(cpufeaturemasks.hdr): $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) FORCE 282 $(shell mkdir -p $(dir $@)) 283 $(call if_changed,gen_featuremasks) 284archprepare: $(cpufeaturemasks.hdr) 285 286### 287# Kernel objects 288 289libs-y += arch/x86/lib/ 290 291# drivers-y are linked after core-y 292drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 293drivers-$(CONFIG_PCI) += arch/x86/pci/ 294 295# suspend and hibernation support 296drivers-$(CONFIG_PM) += arch/x86/power/ 297 298drivers-$(CONFIG_VIDEO) += arch/x86/video/ 299 300#### 301# boot loader support. Several targets are kept for legacy purposes 302 303boot := arch/x86/boot 304 305BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 306 307PHONY += bzImage $(BOOT_TARGETS) 308 309# Default kernel to build 310all: bzImage 311 312# KBUILD_IMAGE specify target image being built 313KBUILD_IMAGE := $(boot)/bzImage 314 315bzImage: vmlinux 316ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 317 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 318endif 319 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 320 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 321 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 322 323$(BOOT_TARGETS): vmlinux 324 $(Q)$(MAKE) $(build)=$(boot) $@ 325 326PHONY += install 327install: 328 $(call cmd,install) 329 330vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg 331vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg 332vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32.so.dbg 333 334archprepare: checkbin 335checkbin: 336ifdef CONFIG_MITIGATION_RETPOLINE 337ifeq ($(RETPOLINE_CFLAGS),) 338 @echo "You are building kernel with non-retpoline compiler." >&2 339 @echo "Please update your compiler." >&2 340 @false 341endif 342endif 343 344ifdef CONFIG_UNWINDER_ORC 345orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h 346orc_hash_sh := $(srctree)/scripts/orc_hash.sh 347targets += $(orc_hash_h) 348quiet_cmd_orc_hash = GEN $@ 349 cmd_orc_hash = mkdir -p $(dir $@); \ 350 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ 351$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE 352 $(call if_changed,orc_hash) 353archprepare: $(orc_hash_h) 354endif 355 356archclean: 357 $(Q)rm -rf $(objtree)/arch/i386 358 $(Q)rm -rf $(objtree)/arch/x86_64 359 360define archhelp 361 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 362 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 363 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 364 echo ' $$(INSTALL_PATH) and run lilo' 365 echo '' 366 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 367 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 368 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 369 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 370 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 371 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 372 echo ' FDARGS="..." arguments for the booted kernel' 373 echo ' FDINITRD=file initrd for the booted kernel' 374 375endef 376