arch/x86/Makefile

   1 # SPDX-License-Identifier: GPL-2.0
   2 # Unified Makefile for i386 and x86_64
   3
   4 # select defconfig based on actual architecture
   5 ifeq ($(ARCH),x86)
   6   ifeq ($(shell uname -m),x86_64)
   7         KBUILD_DEFCONFIG := x86_64_defconfig
   8   else
   9         KBUILD_DEFCONFIG := i386_defconfig
  10   endif
  11 else
  12         KBUILD_DEFCONFIG := $(ARCH)_defconfig
  13 endif
  14
  15 # For gcc stack alignment is specified with -mpreferred-stack-boundary,
  16 # clang has the option -mstack-alignment for that purpose.
  17 ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
  18       cc_stack_align4 := -mpreferred-stack-boundary=2
  19       cc_stack_align8 := -mpreferred-stack-boundary=3
  20 else ifneq ($(call cc-option, -mstack-alignment=16),)
  21       cc_stack_align4 := -mstack-alignment=4
  22       cc_stack_align8 := -mstack-alignment=8
  23 endif
  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 REALMODE_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
  32 REALMODE_CFLAGS += -ffreestanding
  33 REALMODE_CFLAGS += -fno-stack-protector
  34 REALMODE_CFLAGS += -Wno-address-of-packed-member
  35 REALMODE_CFLAGS += $(cc_stack_align4)
  36 REALMODE_CFLAGS += $(CLANG_FLAGS)
  37 export REALMODE_CFLAGS
  38
  39 # BITS is used as extension for files which are available in a 32 bit
  40 # and a 64 bit version to simplify shared Makefiles.
  41 # e.g.: obj-y += foo_$(BITS).o
  42 export 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 #
  51 KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
  52
  53 # Intel CET isn't enabled in the kernel
  54 KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
  55
  56 ifeq ($(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 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
  89 else
  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
 129 endif
 130
 131 ifdef 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 "$$TMP",y,n)
 137         ifeq ($(x32_ld_ok),y)
 138                 CONFIG_X86_X32_ABI := y
 139                 KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
 140                 KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
 141         else
 142                 $(warning CONFIG_X86_X32 enabled but no binutils support)
 143         endif
 144 endif
 145 export CONFIG_X86_X32_ABI
 146
 147 #
 148 # If the function graph tracer is used with mcount instead of fentry,
 149 # '-maccumulate-outgoing-args' is needed to prevent a GCC bug
 150 # (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
 151 #
 152 ifdef CONFIG_FUNCTION_GRAPH_TRACER
 153   ifndef CONFIG_HAVE_FENTRY
 154         ACCUMULATE_OUTGOING_ARGS := 1
 155   endif
 156 endif
 157
 158 ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
 159         # This compiler flag is not supported by Clang:
 160         KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
 161 endif
 162
 163 # Workaround for a gcc prelease that unfortunately was shipped in a suse release
 164 KBUILD_CFLAGS += -Wno-sign-compare
 165 #
 166 KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
 167
 168 # Avoid indirect branches in kernel to deal with Spectre
 169 ifdef CONFIG_RETPOLINE
 170   KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
 171   # Additionally, avoid generating expensive indirect jumps which
 172   # are subject to retpolines for small number of switch cases.
 173   # clang turns off jump table generation by default when under
 174   # retpoline builds, however, gcc does not for x86. This has
 175   # only been fixed starting from gcc stable version 8.4.0 and
 176   # onwards, but not for older ones. See gcc bug #86952.
 177   ifndef CONFIG_CC_IS_CLANG
 178     KBUILD_CFLAGS += -fno-jump-tables
 179   endif
 180 endif
 181
 182 KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
 183
 184 ifdef CONFIG_LTO_CLANG
 185 ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
 186 KBUILD_LDFLAGS  += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
 187 endif
 188 endif
 189
 190 ifdef CONFIG_X86_NEED_RELOCS
 191 LDFLAGS_vmlinux := --emit-relocs --discard-none
 192 else
 193 LDFLAGS_vmlinux :=
 194 endif
 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 #
 201 ifdef CONFIG_X86_64
 202 LDFLAGS_vmlinux += -z max-page-size=0x200000
 203 endif
 204
 205
 206 archscripts: scripts_basic
 207         $(Q)$(MAKE) $(build)=arch/x86/tools relocs
 208
 209 ###
 210 # Syscall table generation
 211
 212 archheaders:
 213         $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
 214
 215 ###
 216 # Kernel objects
 217
 218 head-y := arch/x86/kernel/head_$(BITS).o
 219 head-y += arch/x86/kernel/head$(BITS).o
 220 head-y += arch/x86/kernel/ebda.o
 221 head-y += arch/x86/kernel/platform-quirks.o
 222
 223 libs-y  += arch/x86/lib/
 224
 225 # drivers-y are linked after core-y
 226 drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
 227 drivers-$(CONFIG_PCI)            += arch/x86/pci/
 228
 229 # suspend and hibernation support
 230 drivers-$(CONFIG_PM) += arch/x86/power/
 231
 232 drivers-$(CONFIG_FB) += arch/x86/video/
 233
 234 ####
 235 # boot loader support. Several targets are kept for legacy purposes
 236
 237 boot := arch/x86/boot
 238
 239 BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
 240
 241 PHONY += bzImage $(BOOT_TARGETS)
 242
 243 # Default kernel to build
 244 all: bzImage
 245
 246 # KBUILD_IMAGE specify target image being built
 247 KBUILD_IMAGE := $(boot)/bzImage
 248
 249 bzImage: vmlinux
 250 ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
 251         $(Q)$(MAKE) $(build)=arch/x86/tools posttest
 252 endif
 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
 260 PHONY += install
 261 install:
 262         $(Q)$(MAKE) $(build)=$(boot) $@
 263
 264 PHONY += vdso_install
 265 vdso_install:
 266         $(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
 267
 268 archprepare: checkbin
 269 checkbin:
 270 ifndef CONFIG_CC_HAS_ASM_GOTO
 271         @echo Compiler lacks asm-goto support.
 272         @exit 1
 273 endif
 274 ifdef CONFIG_RETPOLINE
 275 ifeq ($(RETPOLINE_CFLAGS),)
 276         @echo "You are building kernel with non-retpoline compiler." >&2
 277         @echo "Please update your compiler." >&2
 278         @false
 279 endif
 280 endif
 281
 282 archclean:
 283         $(Q)rm -rf $(objtree)/arch/i386
 284         $(Q)rm -rf $(objtree)/arch/x86_64
 285         $(Q)$(MAKE) $(clean)=$(boot)
 286         $(Q)$(MAKE) $(clean)=arch/x86/tools
 287
 288 define archhelp
 289   echo  '* bzImage              - Compressed kernel image (arch/x86/boot/bzImage)'
 290   echo  '  install              - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
 291   echo  '                         (distribution) /sbin/$(INSTALLKERNEL) or install to '
 292   echo  '                         $$(INSTALL_PATH) and run lilo'
 293   echo  ''
 294   echo  '  fdimage              - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
 295   echo  '  fdimage144           - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
 296   echo  '  fdimage288           - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
 297   echo  '  hdimage              - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
 298   echo  '  isoimage             - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
 299   echo  '                         bzdisk/fdimage*/hdimage/isoimage also accept:'
 300   echo  '                         FDARGS="..."  arguments for the booted kernel'
 301   echo  '                         FDINITRD=file initrd for the booted kernel'
 302   echo  ''
 303   echo  '  kvm_guest.config     - Enable Kconfig items for running this kernel as a KVM guest'
 304   echo  '  xen.config           - Enable Kconfig items for running this kernel as a Xen guest'
 305
 306 endef