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),x86_64) 7 KBUILD_DEFCONFIG := x86_64_defconfig 8 else 9 KBUILD_DEFCONFIG := i386_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_CFLAGS += $(call cc-option,-mindirect-branch-cs-prefix) 18RETPOLINE_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register) 19endif 20ifdef CONFIG_CC_IS_CLANG 21RETPOLINE_CFLAGS := -mretpoline-external-thunk 22RETPOLINE_VDSO_CFLAGS := -mretpoline 23endif 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 71 72ifeq ($(CONFIG_X86_KERNEL_IBT),y) 73# 74# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate 75# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK 76# for jump-tables, as such, disable jump-tables for now. 77# 78# (jump-tables are implicitly disabled by RETPOLINE) 79# 80# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816 81# 82KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables) 83else 84KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) 85endif 86 87ifeq ($(CONFIG_X86_32),y) 88 BITS := 32 89 UTS_MACHINE := i386 90 CHECKFLAGS += -D__i386__ 91 92 KBUILD_AFLAGS += -m32 93 KBUILD_CFLAGS += -m32 94 95 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return 96 97 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built 98 # with nonstandard options 99 KBUILD_CFLAGS += -fno-pic 100 101 # Align the stack to the register width instead of using the default 102 # alignment of 16 bytes. This reduces stack usage and the number of 103 # alignment instructions. 104 KBUILD_CFLAGS += $(cc_stack_align4) 105 106 # CPU-specific tuning. Anything which can be shared with UML should go here. 107 include $(srctree)/arch/x86/Makefile_32.cpu 108 KBUILD_CFLAGS += $(cflags-y) 109 110 # temporary until string.h is fixed 111 KBUILD_CFLAGS += -ffreestanding 112 113 ifeq ($(CONFIG_STACKPROTECTOR),y) 114 ifeq ($(CONFIG_SMP),y) 115 KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard 116 else 117 KBUILD_CFLAGS += -mstack-protector-guard=global 118 endif 119 endif 120else 121 BITS := 64 122 UTS_MACHINE := x86_64 123 CHECKFLAGS += -D__x86_64__ 124 125 KBUILD_AFLAGS += -m64 126 KBUILD_CFLAGS += -m64 127 128 # Align jump targets to 1 byte, not the default 16 bytes: 129 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 130 131 # Pack loops tightly as well: 132 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 133 134 # Don't autogenerate traditional x87 instructions 135 KBUILD_CFLAGS += -mno-80387 136 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387) 137 138 # By default gcc and clang use a stack alignment of 16 bytes for x86. 139 # However the standard kernel entry on x86-64 leaves the stack on an 140 # 8-byte boundary. If the compiler isn't informed about the actual 141 # alignment it will generate extra alignment instructions for the 142 # default alignment which keep the stack *mis*aligned. 143 # Furthermore an alignment to the register width reduces stack usage 144 # and the number of alignment instructions. 145 KBUILD_CFLAGS += $(cc_stack_align8) 146 147 # Use -mskip-rax-setup if supported. 148 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) 149 150 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) 151 cflags-$(CONFIG_MK8) += -march=k8 152 cflags-$(CONFIG_MPSC) += -march=nocona 153 cflags-$(CONFIG_MCORE2) += -march=core2 154 cflags-$(CONFIG_MATOM) += -march=atom 155 cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic 156 KBUILD_CFLAGS += $(cflags-y) 157 158 KBUILD_CFLAGS += -mno-red-zone 159 KBUILD_CFLAGS += -mcmodel=kernel 160endif 161 162# 163# If the function graph tracer is used with mcount instead of fentry, 164# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 165# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 166# 167ifdef CONFIG_FUNCTION_GRAPH_TRACER 168 ifndef CONFIG_HAVE_FENTRY 169 ACCUMULATE_OUTGOING_ARGS := 1 170 endif 171endif 172 173ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 174 # This compiler flag is not supported by Clang: 175 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 176endif 177 178# Workaround for a gcc prelease that unfortunately was shipped in a suse release 179KBUILD_CFLAGS += -Wno-sign-compare 180# 181KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 182 183# Avoid indirect branches in kernel to deal with Spectre 184ifdef CONFIG_RETPOLINE 185 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 186 # Additionally, avoid generating expensive indirect jumps which 187 # are subject to retpolines for small number of switch cases. 188 # clang turns off jump table generation by default when under 189 # retpoline builds, however, gcc does not for x86. This has 190 # only been fixed starting from gcc stable version 8.4.0 and 191 # onwards, but not for older ones. See gcc bug #86952. 192 ifndef CONFIG_CC_IS_CLANG 193 KBUILD_CFLAGS += -fno-jump-tables 194 endif 195endif 196 197ifdef CONFIG_SLS 198 KBUILD_CFLAGS += -mharden-sls=all 199endif 200 201KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 202 203ifdef CONFIG_LTO_CLANG 204ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0) 205KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8) 206endif 207endif 208 209ifdef CONFIG_X86_NEED_RELOCS 210LDFLAGS_vmlinux := --emit-relocs --discard-none 211else 212LDFLAGS_vmlinux := 213endif 214 215# 216# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 217# the linker to force 2MB page size regardless of the default page size used 218# by the linker. 219# 220ifdef CONFIG_X86_64 221LDFLAGS_vmlinux += -z max-page-size=0x200000 222endif 223 224 225archscripts: scripts_basic 226 $(Q)$(MAKE) $(build)=arch/x86/tools relocs 227 228### 229# Syscall table generation 230 231archheaders: 232 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 233 234### 235# Kernel objects 236 237head-y := arch/x86/kernel/head_$(BITS).o 238head-y += arch/x86/kernel/head$(BITS).o 239head-y += arch/x86/kernel/ebda.o 240head-y += arch/x86/kernel/platform-quirks.o 241 242libs-y += arch/x86/lib/ 243 244# drivers-y are linked after core-y 245drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 246drivers-$(CONFIG_PCI) += arch/x86/pci/ 247 248# suspend and hibernation support 249drivers-$(CONFIG_PM) += arch/x86/power/ 250 251drivers-$(CONFIG_FB) += arch/x86/video/ 252 253#### 254# boot loader support. Several targets are kept for legacy purposes 255 256boot := arch/x86/boot 257 258BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 259 260PHONY += bzImage $(BOOT_TARGETS) 261 262# Default kernel to build 263all: bzImage 264 265# KBUILD_IMAGE specify target image being built 266KBUILD_IMAGE := $(boot)/bzImage 267 268bzImage: vmlinux 269ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 270 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 271endif 272 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 273 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 274 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 275 276$(BOOT_TARGETS): vmlinux 277 $(Q)$(MAKE) $(build)=$(boot) $@ 278 279PHONY += install 280install: 281 $(call cmd,install) 282 283PHONY += vdso_install 284vdso_install: 285 $(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@ 286 287archprepare: checkbin 288checkbin: 289ifdef CONFIG_RETPOLINE 290ifeq ($(RETPOLINE_CFLAGS),) 291 @echo "You are building kernel with non-retpoline compiler." >&2 292 @echo "Please update your compiler." >&2 293 @false 294endif 295endif 296 297archclean: 298 $(Q)rm -rf $(objtree)/arch/i386 299 $(Q)rm -rf $(objtree)/arch/x86_64 300 301define archhelp 302 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 303 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 304 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 305 echo ' $$(INSTALL_PATH) and run lilo' 306 echo '' 307 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 308 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 309 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 310 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 311 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 312 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 313 echo ' FDARGS="..." arguments for the booted kernel' 314 echo ' FDINITRD=file initrd for the booted kernel' 315 echo '' 316 echo ' kvm_guest.config - Enable Kconfig items for running this kernel as a KVM guest' 317 echo ' xen.config - Enable Kconfig items for running this kernel as a Xen guest' 318 echo ' x86_debug.config - Enable tip tree debugging options for testing' 319 320endef 321