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 := -mindirect-branch=thunk-extern -mindirect-branch-register 17RETPOLINE_VDSO_CFLAGS := -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. 40ifdef CONFIG_CC_IS_GCC 41 cc_stack_align4 := -mpreferred-stack-boundary=2 42 cc_stack_align8 := -mpreferred-stack-boundary=3 43endif 44ifdef CONFIG_CC_IS_CLANG 45 cc_stack_align4 := -mstack-alignment=4 46 cc_stack_align8 := -mstack-alignment=8 47endif 48 49# How to compile the 16-bit code. Note we always compile for -march=i386; 50# that way we can complain to the user if the CPU is insufficient. 51REALMODE_CFLAGS := $(CC_FLAGS_DIALECT) -m16 -g -Os \ 52 -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \ 53 -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ 54 -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ 55 -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none) 56 57REALMODE_CFLAGS += -ffreestanding 58REALMODE_CFLAGS += -fno-stack-protector 59REALMODE_CFLAGS += -Wno-address-of-packed-member 60REALMODE_CFLAGS += $(cc_stack_align4) 61REALMODE_CFLAGS += $(CLANG_FLAGS) 62export REALMODE_CFLAGS 63 64# BITS is used as extension for files which are available in a 32 bit 65# and a 64 bit version to simplify shared Makefiles. 66# e.g.: obj-y += foo_$(BITS).o 67export BITS 68 69# 70# Prevent GCC from generating any FP code by mistake. 71# 72# This must happen before we try the -mpreferred-stack-boundary, see: 73# 74# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 75# 76KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -mno-sse4a 77KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json 78KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2 79 80# 81# CFLAGS for compiling floating point code inside the kernel. 82# 83CC_FLAGS_FPU := -msse -msse2 84ifdef CONFIG_CC_IS_GCC 85CC_FLAGS_FPU += -mhard-float 86endif 87 88ifeq ($(CONFIG_X86_KERNEL_IBT),y) 89# 90# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate 91# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK 92# for jump-tables, as such, disable jump-tables for now. 93# 94# (jump-tables are implicitly disabled by RETPOLINE) 95# 96# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816 97# 98KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables) 99KBUILD_RUSTFLAGS += -Zcf-protection=branch $(if $(call rustc-min-version,109300),-Cjump-tables=n,-Zno-jump-tables) 100else 101KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) 102endif 103 104ifeq ($(CONFIG_X86_32),y) 105 BITS := 32 106 UTS_MACHINE := i386 107 CHECKFLAGS += -D__i386__ 108 109 KBUILD_AFLAGS += -m32 110 KBUILD_CFLAGS += -m32 111 112 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return 113 114 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built 115 # with nonstandard options 116 KBUILD_CFLAGS += -fno-pic 117 118 # Align the stack to the register width instead of using the default 119 # alignment of 16 bytes. This reduces stack usage and the number of 120 # alignment instructions. 121 KBUILD_CFLAGS += $(cc_stack_align4) 122 123 # CPU-specific tuning. Anything which can be shared with UML should go here. 124 include $(srctree)/arch/x86/Makefile_32.cpu 125 KBUILD_CFLAGS += $(cflags-y) 126 127 ifneq ($(call clang-min-version, 160000),y) 128 # https://github.com/llvm/llvm-project/issues/53645 129 KBUILD_CFLAGS += -ffreestanding 130 endif 131 132 percpu_seg := fs 133else 134 BITS := 64 135 UTS_MACHINE := x86_64 136 CHECKFLAGS += -D__x86_64__ 137 138 KBUILD_AFLAGS += -m64 139 KBUILD_CFLAGS += -m64 140 141 # Align jump targets to 1 byte, not the default 16 bytes: 142 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 143 144 # Pack loops tightly as well: 145 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 146 147 # Don't autogenerate traditional x87 instructions 148 KBUILD_CFLAGS += -mno-80387 149 KBUILD_CFLAGS += -mno-fp-ret-in-387 150 151 # By default gcc and clang use a stack alignment of 16 bytes for x86. 152 # However the standard kernel entry on x86-64 leaves the stack on an 153 # 8-byte boundary. If the compiler isn't informed about the actual 154 # alignment it will generate extra alignment instructions for the 155 # default alignment which keep the stack *mis*aligned. 156 # Furthermore an alignment to the register width reduces stack usage 157 # and the number of alignment instructions. 158 KBUILD_CFLAGS += $(cc_stack_align8) 159 160 # Use -mskip-rax-setup if supported. 161 KBUILD_CFLAGS += -mskip-rax-setup 162 163ifdef CONFIG_X86_NATIVE_CPU 164 KBUILD_CFLAGS += -march=native 165 KBUILD_RUSTFLAGS += -Ctarget-cpu=native 166else 167 KBUILD_CFLAGS += -march=x86-64 -mtune=generic 168 KBUILD_RUSTFLAGS += -Ctarget-cpu=x86-64 -Ztune-cpu=generic 169endif 170 171 KBUILD_CFLAGS += -mno-red-zone 172 KBUILD_CFLAGS += -mcmodel=kernel 173 KBUILD_RUSTFLAGS += -Cno-redzone=y 174 KBUILD_RUSTFLAGS += -Ccode-model=kernel 175 176 percpu_seg := gs 177endif 178 179ifeq ($(CONFIG_STACKPROTECTOR),y) 180 ifeq ($(CONFIG_SMP),y) 181 KBUILD_CFLAGS += -mstack-protector-guard-reg=$(percpu_seg) 182 KBUILD_CFLAGS += -mstack-protector-guard-symbol=__ref_stack_chk_guard 183 else 184 KBUILD_CFLAGS += -mstack-protector-guard=global 185 endif 186endif 187 188# 189# If the function graph tracer is used with mcount instead of fentry, 190# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 191# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 192# 193ifdef CONFIG_FUNCTION_GRAPH_TRACER 194 ifndef CONFIG_HAVE_FENTRY 195 ACCUMULATE_OUTGOING_ARGS := 1 196 endif 197endif 198 199ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 200 # This compiler flag is not supported by Clang: 201 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 202endif 203 204# Workaround for a gcc prelease that unfortunately was shipped in a suse release 205KBUILD_CFLAGS += -Wno-sign-compare 206# 207KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 208 209# Avoid indirect branches in kernel to deal with Spectre 210ifdef CONFIG_MITIGATION_RETPOLINE 211 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 212 KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS) 213 # Additionally, avoid generating expensive indirect jumps which 214 # are subject to retpolines for small number of switch cases. 215 # LLVM turns off jump table generation by default when under 216 # retpoline builds, however, gcc does not for x86. This has 217 # only been fixed starting from gcc stable version 8.4.0 and 218 # onwards, but not for older ones. See gcc bug #86952. 219 ifndef CONFIG_CC_IS_CLANG 220 KBUILD_CFLAGS += -fno-jump-tables 221 endif 222endif 223 224ifdef CONFIG_MITIGATION_SLS 225 KBUILD_CFLAGS += -mharden-sls=all 226endif 227 228ifdef CONFIG_CALL_PADDING 229PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 230KBUILD_CFLAGS += $(PADDING_CFLAGS) 231export PADDING_CFLAGS 232 233PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 234KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS) 235export PADDING_RUSTFLAGS 236endif 237 238KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 239 240# 241# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 242# the linker to force 2MB page size regardless of the default page size used 243# by the linker. 244# 245ifdef CONFIG_X86_64 246LDFLAGS_vmlinux += -z max-page-size=0x200000 247endif 248 249 250archscripts: scripts_basic 251 $(Q)$(MAKE) $(build)=arch/x86/tools relocs vdso2c 252 253### 254# Syscall table generation 255 256archheaders: 257 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 258 259### 260# <asm/cpufeaturemasks.h> header generation 261 262cpufeaturemasks.hdr := arch/x86/include/generated/asm/cpufeaturemasks.h 263cpufeaturemasks.awk := $(srctree)/arch/x86/tools/cpufeaturemasks.awk 264cpufeatures_hdr := $(srctree)/arch/x86/include/asm/cpufeatures.h 265targets += $(cpufeaturemasks.hdr) 266 filechk_gen_featuremasks = $(AWK) -f $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) 267 268$(cpufeaturemasks.hdr): $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) FORCE 269 $(shell mkdir -p $(dir $@)) 270 $(call filechk,gen_featuremasks) 271archprepare: $(cpufeaturemasks.hdr) 272 273### 274# Kernel objects 275 276libs-y += arch/x86/lib/ 277 278# drivers-y are linked after core-y 279drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 280drivers-$(CONFIG_PCI) += arch/x86/pci/ 281 282# suspend and hibernation support 283drivers-$(CONFIG_PM) += arch/x86/power/ 284 285drivers-$(CONFIG_VIDEO) += arch/x86/video/ 286 287#### 288# boot loader support. Several targets are kept for legacy purposes 289 290boot := arch/x86/boot 291 292BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 293 294PHONY += bzImage $(BOOT_TARGETS) 295 296# Default kernel to build 297all: bzImage 298 299# KBUILD_IMAGE specify target image being built 300KBUILD_IMAGE := $(boot)/bzImage 301 302bzImage: vmlinux 303ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 304 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 305endif 306 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 307 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 308 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 309 310$(BOOT_TARGETS): vmlinux 311 $(Q)$(MAKE) $(build)=$(boot) $@ 312 313PHONY += install 314install: 315 $(call cmd,install) 316 317vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64/vdso64.so.dbg 318vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdso64/vdsox32.so.dbg 319vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32/vdso32.so.dbg 320 321archprepare: checkbin 322checkbin: 323ifdef CONFIG_MITIGATION_RETPOLINE 324ifeq ($(RETPOLINE_CFLAGS),) 325 @echo "You are building kernel with non-retpoline compiler." >&2 326 @echo "Please update your compiler." >&2 327 @false 328endif 329endif 330 331ifdef CONFIG_UNWINDER_ORC 332orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h 333orc_hash_sh := $(srctree)/scripts/orc_hash.sh 334targets += $(orc_hash_h) 335quiet_cmd_orc_hash = GEN $@ 336 cmd_orc_hash = mkdir -p $(dir $@); \ 337 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ 338$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE 339 $(call if_changed,orc_hash) 340archprepare: $(orc_hash_h) 341endif 342 343archclean: 344 $(Q)rm -rf $(objtree)/arch/i386 345 $(Q)rm -rf $(objtree)/arch/x86_64 346 347define archhelp 348 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 349 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 350 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 351 echo ' $$(INSTALL_PATH) and run lilo' 352 echo '' 353 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 354 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 355 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 356 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 357 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 358 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 359 echo ' FDARGS="..." arguments for the booted kernel' 360 echo ' FDINITRD=file initrd for the booted kernel' 361 362endef 363