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 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 := -std=gnu11 -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 += $(CLANG_FLAGS) 56ifdef CONFIG_CC_IS_CLANG 57REALMODE_CFLAGS += -Wno-gnu 58endif 59export REALMODE_CFLAGS 60 61# BITS is used as extension for files which are available in a 32 bit 62# and a 64 bit version to simplify shared Makefiles. 63# e.g.: obj-y += foo_$(BITS).o 64export BITS 65 66# 67# Prevent GCC from generating any FP code by mistake. 68# 69# This must happen before we try the -mpreferred-stack-boundary, see: 70# 71# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 72# 73KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx 74KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json 75KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2 76 77ifeq ($(CONFIG_X86_KERNEL_IBT),y) 78# 79# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate 80# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK 81# for jump-tables, as such, disable jump-tables for now. 82# 83# (jump-tables are implicitly disabled by RETPOLINE) 84# 85# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816 86# 87KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables) 88KBUILD_RUSTFLAGS += -Zcf-protection=branch -Zno-jump-tables 89else 90KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) 91endif 92 93ifeq ($(CONFIG_X86_32),y) 94 BITS := 32 95 UTS_MACHINE := i386 96 CHECKFLAGS += -D__i386__ 97 98 KBUILD_AFLAGS += -m32 99 KBUILD_CFLAGS += -m32 100 101 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return 102 103 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built 104 # with nonstandard options 105 KBUILD_CFLAGS += -fno-pic 106 107 # Align the stack to the register width instead of using the default 108 # alignment of 16 bytes. This reduces stack usage and the number of 109 # alignment instructions. 110 KBUILD_CFLAGS += $(cc_stack_align4) 111 112 # CPU-specific tuning. Anything which can be shared with UML should go here. 113 include $(srctree)/arch/x86/Makefile_32.cpu 114 KBUILD_CFLAGS += $(cflags-y) 115 116 # temporary until string.h is fixed 117 KBUILD_CFLAGS += -ffreestanding 118 119 ifeq ($(CONFIG_STACKPROTECTOR),y) 120 ifeq ($(CONFIG_SMP),y) 121 KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard 122 else 123 KBUILD_CFLAGS += -mstack-protector-guard=global 124 endif 125 endif 126else 127 BITS := 64 128 UTS_MACHINE := x86_64 129 CHECKFLAGS += -D__x86_64__ 130 131 KBUILD_AFLAGS += -m64 132 KBUILD_CFLAGS += -m64 133 134 # Align jump targets to 1 byte, not the default 16 bytes: 135 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 136 137 # Pack loops tightly as well: 138 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 139 140 # Don't autogenerate traditional x87 instructions 141 KBUILD_CFLAGS += -mno-80387 142 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387) 143 144 # By default gcc and clang use a stack alignment of 16 bytes for x86. 145 # However the standard kernel entry on x86-64 leaves the stack on an 146 # 8-byte boundary. If the compiler isn't informed about the actual 147 # alignment it will generate extra alignment instructions for the 148 # default alignment which keep the stack *mis*aligned. 149 # Furthermore an alignment to the register width reduces stack usage 150 # and the number of alignment instructions. 151 KBUILD_CFLAGS += $(cc_stack_align8) 152 153 # Use -mskip-rax-setup if supported. 154 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) 155 156 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) 157 cflags-$(CONFIG_MK8) += -march=k8 158 cflags-$(CONFIG_MPSC) += -march=nocona 159 cflags-$(CONFIG_MCORE2) += -march=core2 160 cflags-$(CONFIG_MATOM) += -march=atom 161 cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic 162 KBUILD_CFLAGS += $(cflags-y) 163 164 rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8 165 rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona 166 rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2 167 rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom 168 rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic 169 KBUILD_RUSTFLAGS += $(rustflags-y) 170 171 KBUILD_CFLAGS += -mno-red-zone 172 KBUILD_CFLAGS += -mcmodel=kernel 173 KBUILD_RUSTFLAGS += -Cno-redzone=y 174 KBUILD_RUSTFLAGS += -Ccode-model=kernel 175endif 176 177# 178# If the function graph tracer is used with mcount instead of fentry, 179# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 180# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 181# 182ifdef CONFIG_FUNCTION_GRAPH_TRACER 183 ifndef CONFIG_HAVE_FENTRY 184 ACCUMULATE_OUTGOING_ARGS := 1 185 endif 186endif 187 188ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 189 # This compiler flag is not supported by Clang: 190 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 191endif 192 193# Workaround for a gcc prelease that unfortunately was shipped in a suse release 194KBUILD_CFLAGS += -Wno-sign-compare 195# 196KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 197 198# Avoid indirect branches in kernel to deal with Spectre 199ifdef CONFIG_MITIGATION_RETPOLINE 200 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 201 # Additionally, avoid generating expensive indirect jumps which 202 # are subject to retpolines for small number of switch cases. 203 # clang turns off jump table generation by default when under 204 # retpoline builds, however, gcc does not for x86. This has 205 # only been fixed starting from gcc stable version 8.4.0 and 206 # onwards, but not for older ones. See gcc bug #86952. 207 ifndef CONFIG_CC_IS_CLANG 208 KBUILD_CFLAGS += -fno-jump-tables 209 endif 210endif 211 212ifdef CONFIG_MITIGATION_SLS 213 KBUILD_CFLAGS += -mharden-sls=all 214endif 215 216ifdef CONFIG_CALL_PADDING 217PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 218KBUILD_CFLAGS += $(PADDING_CFLAGS) 219export PADDING_CFLAGS 220endif 221 222KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 223 224ifdef CONFIG_X86_NEED_RELOCS 225LDFLAGS_vmlinux := --emit-relocs --discard-none 226else 227LDFLAGS_vmlinux := 228endif 229 230# 231# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 232# the linker to force 2MB page size regardless of the default page size used 233# by the linker. 234# 235ifdef CONFIG_X86_64 236LDFLAGS_vmlinux += -z max-page-size=0x200000 237endif 238 239 240archscripts: scripts_basic 241 $(Q)$(MAKE) $(build)=arch/x86/tools relocs 242 243### 244# Syscall table generation 245 246archheaders: 247 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 248 249### 250# Kernel objects 251 252libs-y += arch/x86/lib/ 253 254# drivers-y are linked after core-y 255drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 256drivers-$(CONFIG_PCI) += arch/x86/pci/ 257 258# suspend and hibernation support 259drivers-$(CONFIG_PM) += arch/x86/power/ 260 261drivers-$(CONFIG_FB_CORE) += arch/x86/video/ 262 263#### 264# boot loader support. Several targets are kept for legacy purposes 265 266boot := arch/x86/boot 267 268BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 269 270PHONY += bzImage $(BOOT_TARGETS) 271 272# Default kernel to build 273all: bzImage 274 275# KBUILD_IMAGE specify target image being built 276KBUILD_IMAGE := $(boot)/bzImage 277 278bzImage: vmlinux 279ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 280 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 281endif 282 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 283 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 284 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 285 286$(BOOT_TARGETS): vmlinux 287 $(Q)$(MAKE) $(build)=$(boot) $@ 288 289PHONY += install 290install: 291 $(call cmd,install) 292 293vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg 294vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg 295vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32.so.dbg 296 297archprepare: checkbin 298checkbin: 299ifdef CONFIG_MITIGATION_RETPOLINE 300ifeq ($(RETPOLINE_CFLAGS),) 301 @echo "You are building kernel with non-retpoline compiler." >&2 302 @echo "Please update your compiler." >&2 303 @false 304endif 305endif 306 307ifdef CONFIG_UNWINDER_ORC 308orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h 309orc_hash_sh := $(srctree)/scripts/orc_hash.sh 310targets += $(orc_hash_h) 311quiet_cmd_orc_hash = GEN $@ 312 cmd_orc_hash = mkdir -p $(dir $@); \ 313 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ 314$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE 315 $(call if_changed,orc_hash) 316archprepare: $(orc_hash_h) 317endif 318 319archclean: 320 $(Q)rm -rf $(objtree)/arch/i386 321 $(Q)rm -rf $(objtree)/arch/x86_64 322 323define archhelp 324 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 325 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 326 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 327 echo ' $$(INSTALL_PATH) and run lilo' 328 echo '' 329 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 330 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 331 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 332 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 333 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 334 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 335 echo ' FDARGS="..." arguments for the booted kernel' 336 echo ' FDINITRD=file initrd for the booted kernel' 337 338endef 339