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 += $(cflags-y) 139 140 ifneq ($(call clang-min-version, 160000),y) 141 # https://github.com/llvm/llvm-project/issues/53645 142 KBUILD_CFLAGS += -ffreestanding 143 endif 144 145 percpu_seg := fs 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 += $(call cc-option,-mskip-rax-setup) 175 176ifdef CONFIG_X86_NATIVE_CPU 177 KBUILD_CFLAGS += -march=native 178 KBUILD_RUSTFLAGS += -Ctarget-cpu=native 179else 180 KBUILD_CFLAGS += -march=x86-64 -mtune=generic 181 KBUILD_RUSTFLAGS += -Ctarget-cpu=x86-64 -Ztune-cpu=generic 182endif 183 184 KBUILD_CFLAGS += -mno-red-zone 185 KBUILD_CFLAGS += -mcmodel=kernel 186 KBUILD_RUSTFLAGS += -Cno-redzone=y 187 KBUILD_RUSTFLAGS += -Ccode-model=kernel 188 189 percpu_seg := gs 190endif 191 192ifeq ($(CONFIG_STACKPROTECTOR),y) 193 ifeq ($(CONFIG_SMP),y) 194 KBUILD_CFLAGS += -mstack-protector-guard-reg=$(percpu_seg) 195 KBUILD_CFLAGS += -mstack-protector-guard-symbol=__ref_stack_chk_guard 196 else 197 KBUILD_CFLAGS += -mstack-protector-guard=global 198 endif 199endif 200 201# 202# If the function graph tracer is used with mcount instead of fentry, 203# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 204# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 205# 206ifdef CONFIG_FUNCTION_GRAPH_TRACER 207 ifndef CONFIG_HAVE_FENTRY 208 ACCUMULATE_OUTGOING_ARGS := 1 209 endif 210endif 211 212ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 213 # This compiler flag is not supported by Clang: 214 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 215endif 216 217# Workaround for a gcc prelease that unfortunately was shipped in a suse release 218KBUILD_CFLAGS += -Wno-sign-compare 219# 220KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 221 222# Avoid indirect branches in kernel to deal with Spectre 223ifdef CONFIG_MITIGATION_RETPOLINE 224 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 225 KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS) 226 # Additionally, avoid generating expensive indirect jumps which 227 # are subject to retpolines for small number of switch cases. 228 # LLVM turns off jump table generation by default when under 229 # retpoline builds, however, gcc does not for x86. This has 230 # only been fixed starting from gcc stable version 8.4.0 and 231 # onwards, but not for older ones. See gcc bug #86952. 232 ifndef CONFIG_CC_IS_CLANG 233 KBUILD_CFLAGS += -fno-jump-tables 234 endif 235endif 236 237ifdef CONFIG_MITIGATION_SLS 238 KBUILD_CFLAGS += -mharden-sls=all 239endif 240 241ifdef CONFIG_CALL_PADDING 242PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 243KBUILD_CFLAGS += $(PADDING_CFLAGS) 244export PADDING_CFLAGS 245 246PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 247KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS) 248export PADDING_RUSTFLAGS 249endif 250 251KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 252 253# 254# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 255# the linker to force 2MB page size regardless of the default page size used 256# by the linker. 257# 258ifdef CONFIG_X86_64 259LDFLAGS_vmlinux += -z max-page-size=0x200000 260endif 261 262 263archscripts: scripts_basic 264 $(Q)$(MAKE) $(build)=arch/x86/tools relocs 265 266### 267# Syscall table generation 268 269archheaders: 270 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 271 272### 273# <asm/cpufeaturemasks.h> header generation 274 275cpufeaturemasks.hdr := arch/x86/include/generated/asm/cpufeaturemasks.h 276cpufeaturemasks.awk := $(srctree)/arch/x86/tools/cpufeaturemasks.awk 277cpufeatures_hdr := $(srctree)/arch/x86/include/asm/cpufeatures.h 278targets += $(cpufeaturemasks.hdr) 279 filechk_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 filechk,gen_featuremasks) 284archprepare: $(cpufeaturemasks.hdr) 285 286### 287# Kernel objects 288 289core-y += arch/x86/boot/startup/ 290libs-y += arch/x86/lib/ 291 292# drivers-y are linked after core-y 293drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 294drivers-$(CONFIG_PCI) += arch/x86/pci/ 295 296# suspend and hibernation support 297drivers-$(CONFIG_PM) += arch/x86/power/ 298 299drivers-$(CONFIG_VIDEO) += arch/x86/video/ 300 301#### 302# boot loader support. Several targets are kept for legacy purposes 303 304boot := arch/x86/boot 305 306BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 307 308PHONY += bzImage $(BOOT_TARGETS) 309 310# Default kernel to build 311all: bzImage 312 313# KBUILD_IMAGE specify target image being built 314KBUILD_IMAGE := $(boot)/bzImage 315 316bzImage: vmlinux 317ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 318 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 319endif 320 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 321 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 322 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 323 324$(BOOT_TARGETS): vmlinux 325 $(Q)$(MAKE) $(build)=$(boot) $@ 326 327PHONY += install 328install: 329 $(call cmd,install) 330 331vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg 332vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg 333vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32.so.dbg 334 335archprepare: checkbin 336checkbin: 337ifdef CONFIG_MITIGATION_RETPOLINE 338ifeq ($(RETPOLINE_CFLAGS),) 339 @echo "You are building kernel with non-retpoline compiler." >&2 340 @echo "Please update your compiler." >&2 341 @false 342endif 343endif 344 345ifdef CONFIG_UNWINDER_ORC 346orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h 347orc_hash_sh := $(srctree)/scripts/orc_hash.sh 348targets += $(orc_hash_h) 349quiet_cmd_orc_hash = GEN $@ 350 cmd_orc_hash = mkdir -p $(dir $@); \ 351 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ 352$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE 353 $(call if_changed,orc_hash) 354archprepare: $(orc_hash_h) 355endif 356 357archclean: 358 $(Q)rm -rf $(objtree)/arch/i386 359 $(Q)rm -rf $(objtree)/arch/x86_64 360 361define archhelp 362 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 363 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 364 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 365 echo ' $$(INSTALL_PATH) and run lilo' 366 echo '' 367 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 368 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 369 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 370 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 371 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 372 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 373 echo ' FDARGS="..." arguments for the booted kernel' 374 echo ' FDINITRD=file initrd for the booted kernel' 375 376endef 377