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