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 := $(ARCH)_defconfig 13endif 14 15# For gcc stack alignment is specified with -mpreferred-stack-boundary, 16# clang has the option -mstack-alignment for that purpose. 17ifneq ($(call cc-option, -mpreferred-stack-boundary=4),) 18 cc_stack_align4 := -mpreferred-stack-boundary=2 19 cc_stack_align8 := -mpreferred-stack-boundary=3 20else ifneq ($(call cc-option, -mstack-alignment=16),) 21 cc_stack_align4 := -mstack-alignment=4 22 cc_stack_align8 := -mstack-alignment=8 23endif 24 25# How to compile the 16-bit code. Note we always compile for -march=i386; 26# that way we can complain to the user if the CPU is insufficient. 27# 28# The -m16 option is supported by GCC >= 4.9 and clang >= 3.5. For 29# older versions of GCC, include an *assembly* header to make sure that 30# gcc doesn't play any games behind our back. 31CODE16GCC_CFLAGS := -m32 -Wa,$(srctree)/arch/x86/boot/code16gcc.h 32M16_CFLAGS := $(call cc-option, -m16, $(CODE16GCC_CFLAGS)) 33 34REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \ 35 -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ 36 -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ 37 -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none) 38 39REALMODE_CFLAGS += -ffreestanding 40REALMODE_CFLAGS += -fno-stack-protector 41REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member) 42REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4)) 43REALMODE_CFLAGS += $(CLANG_FLAGS) 44export REALMODE_CFLAGS 45 46# BITS is used as extension for files which are available in a 32 bit 47# and a 64 bit version to simplify shared Makefiles. 48# e.g.: obj-y += foo_$(BITS).o 49export BITS 50 51# 52# Prevent GCC from generating any FP code by mistake. 53# 54# This must happen before we try the -mpreferred-stack-boundary, see: 55# 56# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 57# 58KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow 59KBUILD_CFLAGS += $(call cc-option,-mno-avx,) 60 61# Intel CET isn't enabled in the kernel 62KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) 63 64ifeq ($(CONFIG_X86_32),y) 65 BITS := 32 66 UTS_MACHINE := i386 67 CHECKFLAGS += -D__i386__ 68 69 biarch := $(call cc-option,-m32) 70 KBUILD_AFLAGS += $(biarch) 71 KBUILD_CFLAGS += $(biarch) 72 73 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return 74 75 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built 76 # with nonstandard options 77 KBUILD_CFLAGS += -fno-pic 78 79 # Align the stack to the register width instead of using the default 80 # alignment of 16 bytes. This reduces stack usage and the number of 81 # alignment instructions. 82 KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4)) 83 84 # CPU-specific tuning. Anything which can be shared with UML should go here. 85 include arch/x86/Makefile_32.cpu 86 KBUILD_CFLAGS += $(cflags-y) 87 88 # temporary until string.h is fixed 89 KBUILD_CFLAGS += -ffreestanding 90else 91 BITS := 64 92 UTS_MACHINE := x86_64 93 CHECKFLAGS += -D__x86_64__ 94 95 biarch := -m64 96 KBUILD_AFLAGS += -m64 97 KBUILD_CFLAGS += -m64 98 99 # Align jump targets to 1 byte, not the default 16 bytes: 100 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 101 102 # Pack loops tightly as well: 103 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 104 105 # Don't autogenerate traditional x87 instructions 106 KBUILD_CFLAGS += $(call cc-option,-mno-80387) 107 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387) 108 109 # By default gcc and clang use a stack alignment of 16 bytes for x86. 110 # However the standard kernel entry on x86-64 leaves the stack on an 111 # 8-byte boundary. If the compiler isn't informed about the actual 112 # alignment it will generate extra alignment instructions for the 113 # default alignment which keep the stack *mis*aligned. 114 # Furthermore an alignment to the register width reduces stack usage 115 # and the number of alignment instructions. 116 KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8)) 117 118 # Use -mskip-rax-setup if supported. 119 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) 120 121 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) 122 cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8) 123 cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona) 124 125 cflags-$(CONFIG_MCORE2) += \ 126 $(call cc-option,-march=core2,$(call cc-option,-mtune=generic)) 127 cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \ 128 $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic)) 129 cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic) 130 KBUILD_CFLAGS += $(cflags-y) 131 132 KBUILD_CFLAGS += -mno-red-zone 133 KBUILD_CFLAGS += -mcmodel=kernel 134endif 135 136ifdef CONFIG_X86_X32 137 x32_ld_ok := $(call try-run,\ 138 /bin/echo -e '1: .quad 1b' | \ 139 $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \ 140 $(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMPO" && \ 141 $(LD) -m elf32_x86_64 "$$TMPO" -o "$$TMP",y,n) 142 ifeq ($(x32_ld_ok),y) 143 CONFIG_X86_X32_ABI := y 144 KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI 145 KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI 146 else 147 $(warning CONFIG_X86_X32 enabled but no binutils support) 148 endif 149endif 150export CONFIG_X86_X32_ABI 151 152# 153# If the function graph tracer is used with mcount instead of fentry, 154# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 155# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 156# 157ifdef CONFIG_FUNCTION_GRAPH_TRACER 158 ifndef CONFIG_HAVE_FENTRY 159 ACCUMULATE_OUTGOING_ARGS := 1 160 else 161 ifeq ($(call cc-option-yn, -mfentry), n) 162 ACCUMULATE_OUTGOING_ARGS := 1 163 164 # GCC ignores '-maccumulate-outgoing-args' when used with '-Os'. 165 # If '-Os' is enabled, disable it and print a warning. 166 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE 167 undefine CONFIG_CC_OPTIMIZE_FOR_SIZE 168 $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE. Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.) 169 endif 170 171 endif 172 endif 173endif 174 175ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 176 # This compiler flag is not supported by Clang: 177 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 178endif 179 180# Workaround for a gcc prelease that unfortunately was shipped in a suse release 181KBUILD_CFLAGS += -Wno-sign-compare 182# 183KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 184 185# Avoid indirect branches in kernel to deal with Spectre 186ifdef CONFIG_RETPOLINE 187 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 188 # Additionally, avoid generating expensive indirect jumps which 189 # are subject to retpolines for small number of switch cases. 190 # clang turns off jump table generation by default when under 191 # retpoline builds, however, gcc does not for x86. This has 192 # only been fixed starting from gcc stable version 8.4.0 and 193 # onwards, but not for older ones. See gcc bug #86952. 194 ifndef CONFIG_CC_IS_CLANG 195 KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables) 196 endif 197endif 198 199ifdef CONFIG_SLS 200 KBUILD_CFLAGS += -mharden-sls=all 201endif 202 203KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 204 205ifdef CONFIG_X86_NEED_RELOCS 206LDFLAGS_vmlinux := --emit-relocs --discard-none 207else 208LDFLAGS_vmlinux := 209endif 210 211# 212# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 213# the linker to force 2MB page size regardless of the default page size used 214# by the linker. 215# 216ifdef CONFIG_X86_64 217LDFLAGS_vmlinux += -z max-page-size=0x200000 218endif 219 220 221archscripts: scripts_basic 222 $(Q)$(MAKE) $(build)=arch/x86/tools relocs 223 224### 225# Syscall table generation 226 227archheaders: 228 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 229 230### 231# Kernel objects 232 233head-y := arch/x86/kernel/head_$(BITS).o 234head-y += arch/x86/kernel/head$(BITS).o 235head-y += arch/x86/kernel/ebda.o 236head-y += arch/x86/kernel/platform-quirks.o 237 238libs-y += arch/x86/lib/ 239 240# See arch/x86/Kbuild for content of core part of the kernel 241core-y += arch/x86/ 242 243# drivers-y are linked after core-y 244drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 245drivers-$(CONFIG_PCI) += arch/x86/pci/ 246 247# must be linked after kernel/ 248drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/ 249 250# suspend and hibernation support 251drivers-$(CONFIG_PM) += arch/x86/power/ 252 253drivers-$(CONFIG_FB) += arch/x86/video/ 254 255#### 256# boot loader support. Several targets are kept for legacy purposes 257 258boot := arch/x86/boot 259 260BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 isoimage 261 262PHONY += bzImage $(BOOT_TARGETS) 263 264# Default kernel to build 265all: bzImage 266 267# KBUILD_IMAGE specify target image being built 268KBUILD_IMAGE := $(boot)/bzImage 269 270bzImage: vmlinux 271ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 272 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 273endif 274 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 275 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 276 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 277 278$(BOOT_TARGETS): vmlinux 279 $(Q)$(MAKE) $(build)=$(boot) $@ 280 281PHONY += install bzlilo 282install bzlilo: 283 $(Q)$(MAKE) $(build)=$(boot) $@ 284 285PHONY += vdso_install 286vdso_install: 287 $(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@ 288 289archprepare: checkbin 290checkbin: 291ifndef CONFIG_CC_HAS_ASM_GOTO 292 @echo Compiler lacks asm-goto support. 293 @exit 1 294endif 295ifdef CONFIG_RETPOLINE 296ifeq ($(RETPOLINE_CFLAGS),) 297 @echo "You are building kernel with non-retpoline compiler." >&2 298 @echo "Please update your compiler." >&2 299 @false 300endif 301endif 302 303archclean: 304 $(Q)rm -rf $(objtree)/arch/i386 305 $(Q)rm -rf $(objtree)/arch/x86_64 306 $(Q)$(MAKE) $(clean)=$(boot) 307 $(Q)$(MAKE) $(clean)=arch/x86/tools 308 309define archhelp 310 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 311 echo ' install - Install kernel using' 312 echo ' (your) ~/bin/$(INSTALLKERNEL) or' 313 echo ' (distribution) /sbin/$(INSTALLKERNEL) or' 314 echo ' install to $$(INSTALL_PATH) and run lilo' 315 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 316 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 317 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 318 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 319 echo ' bzdisk/fdimage*/isoimage also accept:' 320 echo ' FDARGS="..." arguments for the booted kernel' 321 echo ' FDINITRD=file initrd for the booted kernel' 322endef 323