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_RETHUNK 26RETHUNK_CFLAGS := -mfunction-return=thunk-extern 27RETPOLINE_CFLAGS += $(RETHUNK_CFLAGS) 28endif 29 30export RETHUNK_CFLAGS 31export RETPOLINE_CFLAGS 32export RETPOLINE_VDSO_CFLAGS 33 34# For gcc stack alignment is specified with -mpreferred-stack-boundary, 35# clang has the option -mstack-alignment for that purpose. 36ifneq ($(call cc-option, -mpreferred-stack-boundary=4),) 37 cc_stack_align4 := -mpreferred-stack-boundary=2 38 cc_stack_align8 := -mpreferred-stack-boundary=3 39else ifneq ($(call cc-option, -mstack-alignment=16),) 40 cc_stack_align4 := -mstack-alignment=4 41 cc_stack_align8 := -mstack-alignment=8 42endif 43 44# How to compile the 16-bit code. Note we always compile for -march=i386; 45# that way we can complain to the user if the CPU is insufficient. 46REALMODE_CFLAGS := -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \ 47 -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ 48 -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ 49 -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none) 50 51REALMODE_CFLAGS += -ffreestanding 52REALMODE_CFLAGS += -fno-stack-protector 53REALMODE_CFLAGS += -Wno-address-of-packed-member 54REALMODE_CFLAGS += $(cc_stack_align4) 55REALMODE_CFLAGS += $(CLANG_FLAGS) 56export REALMODE_CFLAGS 57 58# BITS is used as extension for files which are available in a 32 bit 59# and a 64 bit version to simplify shared Makefiles. 60# e.g.: obj-y += foo_$(BITS).o 61export BITS 62 63# 64# Prevent GCC from generating any FP code by mistake. 65# 66# This must happen before we try the -mpreferred-stack-boundary, see: 67# 68# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 69# 70KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx 71KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2 72 73ifeq ($(CONFIG_X86_KERNEL_IBT),y) 74# 75# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate 76# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK 77# for jump-tables, as such, disable jump-tables for now. 78# 79# (jump-tables are implicitly disabled by RETPOLINE) 80# 81# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816 82# 83KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables) 84else 85KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) 86endif 87 88ifeq ($(CONFIG_X86_32),y) 89 BITS := 32 90 UTS_MACHINE := i386 91 CHECKFLAGS += -D__i386__ 92 93 KBUILD_AFLAGS += -m32 94 KBUILD_CFLAGS += -m32 95 96 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return 97 98 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built 99 # with nonstandard options 100 KBUILD_CFLAGS += -fno-pic 101 102 # Align the stack to the register width instead of using the default 103 # alignment of 16 bytes. This reduces stack usage and the number of 104 # alignment instructions. 105 KBUILD_CFLAGS += $(cc_stack_align4) 106 107 # CPU-specific tuning. Anything which can be shared with UML should go here. 108 include $(srctree)/arch/x86/Makefile_32.cpu 109 KBUILD_CFLAGS += $(cflags-y) 110 111 # temporary until string.h is fixed 112 KBUILD_CFLAGS += -ffreestanding 113 114 ifeq ($(CONFIG_STACKPROTECTOR),y) 115 ifeq ($(CONFIG_SMP),y) 116 KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard 117 else 118 KBUILD_CFLAGS += -mstack-protector-guard=global 119 endif 120 endif 121else 122 BITS := 64 123 UTS_MACHINE := x86_64 124 CHECKFLAGS += -D__x86_64__ 125 126 KBUILD_AFLAGS += -m64 127 KBUILD_CFLAGS += -m64 128 129 # Align jump targets to 1 byte, not the default 16 bytes: 130 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 131 132 # Pack loops tightly as well: 133 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 134 135 # Don't autogenerate traditional x87 instructions 136 KBUILD_CFLAGS += -mno-80387 137 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387) 138 139 # By default gcc and clang use a stack alignment of 16 bytes for x86. 140 # However the standard kernel entry on x86-64 leaves the stack on an 141 # 8-byte boundary. If the compiler isn't informed about the actual 142 # alignment it will generate extra alignment instructions for the 143 # default alignment which keep the stack *mis*aligned. 144 # Furthermore an alignment to the register width reduces stack usage 145 # and the number of alignment instructions. 146 KBUILD_CFLAGS += $(cc_stack_align8) 147 148 # Use -mskip-rax-setup if supported. 149 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) 150 151 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) 152 cflags-$(CONFIG_MK8) += -march=k8 153 cflags-$(CONFIG_MPSC) += -march=nocona 154 cflags-$(CONFIG_MCORE2) += -march=core2 155 cflags-$(CONFIG_MATOM) += -march=atom 156 cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic 157 KBUILD_CFLAGS += $(cflags-y) 158 159 rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8 160 rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona 161 rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2 162 rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom 163 rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic 164 KBUILD_RUSTFLAGS += $(rustflags-y) 165 166 KBUILD_CFLAGS += -mno-red-zone 167 KBUILD_CFLAGS += -mcmodel=kernel 168 KBUILD_RUSTFLAGS += -Cno-redzone=y 169 KBUILD_RUSTFLAGS += -Ccode-model=kernel 170endif 171 172# 173# If the function graph tracer is used with mcount instead of fentry, 174# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 175# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 176# 177ifdef CONFIG_FUNCTION_GRAPH_TRACER 178 ifndef CONFIG_HAVE_FENTRY 179 ACCUMULATE_OUTGOING_ARGS := 1 180 endif 181endif 182 183ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 184 # This compiler flag is not supported by Clang: 185 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 186endif 187 188# Workaround for a gcc prelease that unfortunately was shipped in a suse release 189KBUILD_CFLAGS += -Wno-sign-compare 190# 191KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 192 193# Avoid indirect branches in kernel to deal with Spectre 194ifdef CONFIG_RETPOLINE 195 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 196 # Additionally, avoid generating expensive indirect jumps which 197 # are subject to retpolines for small number of switch cases. 198 # clang turns off jump table generation by default when under 199 # retpoline builds, however, gcc does not for x86. This has 200 # only been fixed starting from gcc stable version 8.4.0 and 201 # onwards, but not for older ones. See gcc bug #86952. 202 ifndef CONFIG_CC_IS_CLANG 203 KBUILD_CFLAGS += -fno-jump-tables 204 endif 205endif 206 207ifdef CONFIG_SLS 208 KBUILD_CFLAGS += -mharden-sls=all 209endif 210 211ifdef CONFIG_CALL_PADDING 212PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 213KBUILD_CFLAGS += $(PADDING_CFLAGS) 214export PADDING_CFLAGS 215endif 216 217KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 218 219ifdef CONFIG_LTO_CLANG 220ifeq ($(call test-lt, $(CONFIG_LLD_VERSION), 130000),y) 221KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8) 222endif 223endif 224 225ifdef CONFIG_X86_NEED_RELOCS 226LDFLAGS_vmlinux := --emit-relocs --discard-none 227else 228LDFLAGS_vmlinux := 229endif 230 231# 232# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 233# the linker to force 2MB page size regardless of the default page size used 234# by the linker. 235# 236ifdef CONFIG_X86_64 237LDFLAGS_vmlinux += -z max-page-size=0x200000 238endif 239 240 241archscripts: scripts_basic 242 $(Q)$(MAKE) $(build)=arch/x86/tools relocs 243 244### 245# Syscall table generation 246 247archheaders: 248 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 249 250### 251# Kernel objects 252 253libs-y += arch/x86/lib/ 254 255# drivers-y are linked after core-y 256drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 257drivers-$(CONFIG_PCI) += arch/x86/pci/ 258 259# suspend and hibernation support 260drivers-$(CONFIG_PM) += arch/x86/power/ 261 262drivers-$(CONFIG_FB_CORE) += arch/x86/video/ 263 264#### 265# boot loader support. Several targets are kept for legacy purposes 266 267boot := arch/x86/boot 268 269BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 270 271PHONY += bzImage $(BOOT_TARGETS) 272 273# Default kernel to build 274all: bzImage 275 276# KBUILD_IMAGE specify target image being built 277KBUILD_IMAGE := $(boot)/bzImage 278 279bzImage: vmlinux 280ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 281 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 282endif 283 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 284 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 285 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 286 287$(BOOT_TARGETS): vmlinux 288 $(Q)$(MAKE) $(build)=$(boot) $@ 289 290PHONY += install 291install: 292 $(call cmd,install) 293 294PHONY += vdso_install 295vdso_install: 296 $(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@ 297 298archprepare: checkbin 299checkbin: 300ifdef CONFIG_RETPOLINE 301ifeq ($(RETPOLINE_CFLAGS),) 302 @echo "You are building kernel with non-retpoline compiler." >&2 303 @echo "Please update your compiler." >&2 304 @false 305endif 306endif 307 308ifdef CONFIG_UNWINDER_ORC 309orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h 310orc_hash_sh := $(srctree)/scripts/orc_hash.sh 311targets += $(orc_hash_h) 312quiet_cmd_orc_hash = GEN $@ 313 cmd_orc_hash = mkdir -p $(dir $@); \ 314 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ 315$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE 316 $(call if_changed,orc_hash) 317archprepare: $(orc_hash_h) 318endif 319 320archclean: 321 $(Q)rm -rf $(objtree)/arch/i386 322 $(Q)rm -rf $(objtree)/arch/x86_64 323 324define archhelp 325 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 326 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 327 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 328 echo ' $$(INSTALL_PATH) and run lilo' 329 echo '' 330 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 331 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 332 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 333 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 334 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 335 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 336 echo ' FDARGS="..." arguments for the booted kernel' 337 echo ' FDINITRD=file initrd for the booted kernel' 338 339endef 340