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. 27REALMODE_CFLAGS := -m16 -g -Os -DDISABLE_BRANCH_PROFILING \ 28 -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ 29 -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ 30 -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none) 31 32REALMODE_CFLAGS += -ffreestanding 33REALMODE_CFLAGS += -fno-stack-protector 34REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member) 35REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4)) 36REALMODE_CFLAGS += $(CLANG_FLAGS) 37export REALMODE_CFLAGS 38 39# BITS is used as extension for files which are available in a 32 bit 40# and a 64 bit version to simplify shared Makefiles. 41# e.g.: obj-y += foo_$(BITS).o 42export BITS 43 44# 45# Prevent GCC from generating any FP code by mistake. 46# 47# This must happen before we try the -mpreferred-stack-boundary, see: 48# 49# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 50# 51KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow 52KBUILD_CFLAGS += $(call cc-option,-mno-avx,) 53 54# Intel CET isn't enabled in the kernel 55KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) 56 57ifeq ($(CONFIG_X86_32),y) 58 BITS := 32 59 UTS_MACHINE := i386 60 CHECKFLAGS += -D__i386__ 61 62 biarch := $(call cc-option,-m32) 63 KBUILD_AFLAGS += $(biarch) 64 KBUILD_CFLAGS += $(biarch) 65 66 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return 67 68 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built 69 # with nonstandard options 70 KBUILD_CFLAGS += -fno-pic 71 72 # Align the stack to the register width instead of using the default 73 # alignment of 16 bytes. This reduces stack usage and the number of 74 # alignment instructions. 75 KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4)) 76 77 # CPU-specific tuning. Anything which can be shared with UML should go here. 78 include $(srctree)/arch/x86/Makefile_32.cpu 79 KBUILD_CFLAGS += $(cflags-y) 80 81 # temporary until string.h is fixed 82 KBUILD_CFLAGS += -ffreestanding 83 84 ifeq ($(CONFIG_STACKPROTECTOR),y) 85 ifeq ($(CONFIG_SMP),y) 86 KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard 87 else 88 KBUILD_CFLAGS += -mstack-protector-guard=global 89 endif 90 endif 91else 92 BITS := 64 93 UTS_MACHINE := x86_64 94 CHECKFLAGS += -D__x86_64__ 95 96 biarch := -m64 97 KBUILD_AFLAGS += -m64 98 KBUILD_CFLAGS += -m64 99 100 # Align jump targets to 1 byte, not the default 16 bytes: 101 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 102 103 # Pack loops tightly as well: 104 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 105 106 # Don't autogenerate traditional x87 instructions 107 KBUILD_CFLAGS += $(call cc-option,-mno-80387) 108 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387) 109 110 # By default gcc and clang use a stack alignment of 16 bytes for x86. 111 # However the standard kernel entry on x86-64 leaves the stack on an 112 # 8-byte boundary. If the compiler isn't informed about the actual 113 # alignment it will generate extra alignment instructions for the 114 # default alignment which keep the stack *mis*aligned. 115 # Furthermore an alignment to the register width reduces stack usage 116 # and the number of alignment instructions. 117 KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8)) 118 119 # Use -mskip-rax-setup if supported. 120 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) 121 122 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu) 123 cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8) 124 cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona) 125 126 cflags-$(CONFIG_MCORE2) += \ 127 $(call cc-option,-march=core2,$(call cc-option,-mtune=generic)) 128 cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \ 129 $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic)) 130 cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic) 131 KBUILD_CFLAGS += $(cflags-y) 132 133 KBUILD_CFLAGS += -mno-red-zone 134 KBUILD_CFLAGS += -mcmodel=kernel 135endif 136 137ifdef CONFIG_X86_X32 138 x32_ld_ok := $(call try-run,\ 139 /bin/echo -e '1: .quad 1b' | \ 140 $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \ 141 $(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMP.o" && \ 142 $(LD) -m elf32_x86_64 "$$TMP.o" -o "$$TMP",y,n) 143 ifeq ($(x32_ld_ok),y) 144 CONFIG_X86_X32_ABI := y 145 KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI 146 KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI 147 else 148 $(warning CONFIG_X86_X32 enabled but no binutils support) 149 endif 150endif 151export CONFIG_X86_X32_ABI 152 153# 154# If the function graph tracer is used with mcount instead of fentry, 155# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 156# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 157# 158ifdef CONFIG_FUNCTION_GRAPH_TRACER 159 ifndef CONFIG_HAVE_FENTRY 160 ACCUMULATE_OUTGOING_ARGS := 1 161 else 162 ifeq ($(call cc-option-yn, -mfentry), n) 163 ACCUMULATE_OUTGOING_ARGS := 1 164 165 # GCC ignores '-maccumulate-outgoing-args' when used with '-Os'. 166 # If '-Os' is enabled, disable it and print a warning. 167 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE 168 undefine CONFIG_CC_OPTIMIZE_FOR_SIZE 169 $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE. Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.) 170 endif 171 172 endif 173 endif 174endif 175 176ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 177 # This compiler flag is not supported by Clang: 178 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 179endif 180 181# Workaround for a gcc prelease that unfortunately was shipped in a suse release 182KBUILD_CFLAGS += -Wno-sign-compare 183# 184KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 185 186# Avoid indirect branches in kernel to deal with Spectre 187ifdef CONFIG_RETPOLINE 188 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 189 # Additionally, avoid generating expensive indirect jumps which 190 # are subject to retpolines for small number of switch cases. 191 # clang turns off jump table generation by default when under 192 # retpoline builds, however, gcc does not for x86. This has 193 # only been fixed starting from gcc stable version 8.4.0 and 194 # onwards, but not for older ones. See gcc bug #86952. 195 ifndef CONFIG_CC_IS_CLANG 196 KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables) 197 endif 198endif 199 200KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 201 202ifdef CONFIG_LTO_CLANG 203ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0) 204KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8) 205endif 206endif 207 208ifdef CONFIG_X86_NEED_RELOCS 209LDFLAGS_vmlinux := --emit-relocs --discard-none 210else 211LDFLAGS_vmlinux := 212endif 213 214# 215# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 216# the linker to force 2MB page size regardless of the default page size used 217# by the linker. 218# 219ifdef CONFIG_X86_64 220LDFLAGS_vmlinux += -z max-page-size=0x200000 221endif 222 223 224archscripts: scripts_basic 225 $(Q)$(MAKE) $(build)=arch/x86/tools relocs 226 227### 228# Syscall table generation 229 230archheaders: 231 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 232 233### 234# Kernel objects 235 236head-y := arch/x86/kernel/head_$(BITS).o 237head-y += arch/x86/kernel/head$(BITS).o 238head-y += arch/x86/kernel/ebda.o 239head-y += arch/x86/kernel/platform-quirks.o 240 241libs-y += arch/x86/lib/ 242 243# drivers-y are linked after core-y 244drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 245drivers-$(CONFIG_PCI) += arch/x86/pci/ 246 247# suspend and hibernation support 248drivers-$(CONFIG_PM) += arch/x86/power/ 249 250drivers-$(CONFIG_FB) += arch/x86/video/ 251 252#### 253# boot loader support. Several targets are kept for legacy purposes 254 255boot := arch/x86/boot 256 257BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 258 259PHONY += bzImage $(BOOT_TARGETS) 260 261# Default kernel to build 262all: bzImage 263 264# KBUILD_IMAGE specify target image being built 265KBUILD_IMAGE := $(boot)/bzImage 266 267bzImage: vmlinux 268ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 269 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 270endif 271 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 272 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 273 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 274 275$(BOOT_TARGETS): vmlinux 276 $(Q)$(MAKE) $(build)=$(boot) $@ 277 278PHONY += install bzlilo 279install bzlilo: 280 $(Q)$(MAKE) $(build)=$(boot) $@ 281 282PHONY += vdso_install 283vdso_install: 284 $(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@ 285 286archprepare: checkbin 287checkbin: 288ifndef CONFIG_CC_HAS_ASM_GOTO 289 @echo Compiler lacks asm-goto support. 290 @exit 1 291endif 292ifdef CONFIG_RETPOLINE 293ifeq ($(RETPOLINE_CFLAGS),) 294 @echo "You are building kernel with non-retpoline compiler." >&2 295 @echo "Please update your compiler." >&2 296 @false 297endif 298endif 299 300archclean: 301 $(Q)rm -rf $(objtree)/arch/i386 302 $(Q)rm -rf $(objtree)/arch/x86_64 303 $(Q)$(MAKE) $(clean)=$(boot) 304 $(Q)$(MAKE) $(clean)=arch/x86/tools 305 306define archhelp 307 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 308 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 309 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 310 echo ' $$(INSTALL_PATH) and run lilo' 311 echo '' 312 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 313 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 314 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 315 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 316 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 317 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 318 echo ' FDARGS="..." arguments for the booted kernel' 319 echo ' FDINITRD=file initrd for the booted kernel' 320 echo '' 321 echo ' kvm_guest.config - Enable Kconfig items for running this kernel as a KVM guest' 322 echo ' xen.config - Enable Kconfig items for running this kernel as a Xen guest' 323 324endef 325