linux/arch/x86/Makefile
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   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        $(Q)$(MAKE) $(clean)=$(boot)
 287        $(Q)$(MAKE) $(clean)=arch/x86/tools
 288
 289define archhelp
 290  echo  '* bzImage              - Compressed kernel image (arch/x86/boot/bzImage)'
 291  echo  '  install              - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
 292  echo  '                         (distribution) /sbin/$(INSTALLKERNEL) or install to '
 293  echo  '                         $$(INSTALL_PATH) and run lilo'
 294  echo  ''
 295  echo  '  fdimage              - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
 296  echo  '  fdimage144           - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
 297  echo  '  fdimage288           - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
 298  echo  '  hdimage              - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
 299  echo  '  isoimage             - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
 300  echo  '                         bzdisk/fdimage*/hdimage/isoimage also accept:'
 301  echo  '                         FDARGS="..."  arguments for the booted kernel'
 302  echo  '                         FDINITRD=file initrd for the booted kernel'
 303  echo  ''
 304  echo  '  kvm_guest.config     - Enable Kconfig items for running this kernel as a KVM guest'
 305  echo  '  xen.config           - Enable Kconfig items for running this kernel as a Xen guest'
 306
 307endef
 308