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
  31
  32 REALMODE_CFLAGS += -ffreestanding
  33 REALMODE_CFLAGS += -fno-stack-protector
  34 REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member)
  35 REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
  36 export REALMODE_CFLAGS
  37
  38 # BITS is used as extension for files which are available in a 32 bit
  39 # and a 64 bit version to simplify shared Makefiles.
  40 # e.g.: obj-y += foo_$(BITS).o
  41 export BITS
  42
  43 #
  44 # Prevent GCC from generating any FP code by mistake.
  45 #
  46 # This must happen before we try the -mpreferred-stack-boundary, see:
  47 #
  48 #    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
  49 #
  50 KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
  51 KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
  52
  53 ifeq ($(CONFIG_X86_32),y)
  54         BITS := 32
  55         UTS_MACHINE := i386
  56         CHECKFLAGS += -D__i386__
  57
  58         biarch := $(call cc-option,-m32)
  59         KBUILD_AFLAGS += $(biarch)
  60         KBUILD_CFLAGS += $(biarch)
  61
  62         KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
  63
  64         # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
  65         # with nonstandard options
  66         KBUILD_CFLAGS += -fno-pic
  67
  68         # Align the stack to the register width instead of using the default
  69         # alignment of 16 bytes. This reduces stack usage and the number of
  70         # alignment instructions.
  71         KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
  72
  73         # CPU-specific tuning. Anything which can be shared with UML should go here.
  74         include arch/x86/Makefile_32.cpu
  75         KBUILD_CFLAGS += $(cflags-y)
  76
  77         # temporary until string.h is fixed
  78         KBUILD_CFLAGS += -ffreestanding
  79 else
  80         BITS := 64
  81         UTS_MACHINE := x86_64
  82         CHECKFLAGS += -D__x86_64__
  83
  84         biarch := -m64
  85         KBUILD_AFLAGS += -m64
  86         KBUILD_CFLAGS += -m64
  87
  88         # Align jump targets to 1 byte, not the default 16 bytes:
  89         KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
  90
  91         # Pack loops tightly as well:
  92         KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
  93
  94         # Don't autogenerate traditional x87 instructions
  95         KBUILD_CFLAGS += $(call cc-option,-mno-80387)
  96         KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
  97
  98         # By default gcc and clang use a stack alignment of 16 bytes for x86.
  99         # However the standard kernel entry on x86-64 leaves the stack on an
 100         # 8-byte boundary. If the compiler isn't informed about the actual
 101         # alignment it will generate extra alignment instructions for the
 102         # default alignment which keep the stack *mis*aligned.
 103         # Furthermore an alignment to the register width reduces stack usage
 104         # and the number of alignment instructions.
 105         KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
 106
 107         # Use -mskip-rax-setup if supported.
 108         KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
 109
 110         # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
 111         cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
 112         cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
 113
 114         cflags-$(CONFIG_MCORE2) += \
 115                 $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
 116         cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
 117                 $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
 118         cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
 119         KBUILD_CFLAGS += $(cflags-y)
 120
 121         KBUILD_CFLAGS += -mno-red-zone
 122         KBUILD_CFLAGS += -mcmodel=kernel
 123 endif
 124
 125 ifdef CONFIG_X86_X32
 126         x32_ld_ok := $(call try-run,\
 127                         /bin/echo -e '1: .quad 1b' | \
 128                         $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
 129                         $(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMPO" && \
 130                         $(LD) -m elf32_x86_64 "$$TMPO" -o "$$TMP",y,n)
 131         ifeq ($(x32_ld_ok),y)
 132                 CONFIG_X86_X32_ABI := y
 133                 KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
 134                 KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
 135         else
 136                 $(warning CONFIG_X86_X32 enabled but no binutils support)
 137         endif
 138 endif
 139 export CONFIG_X86_X32_ABI
 140
 141 #
 142 # If the function graph tracer is used with mcount instead of fentry,
 143 # '-maccumulate-outgoing-args' is needed to prevent a GCC bug
 144 # (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
 145 #
 146 ifdef CONFIG_FUNCTION_GRAPH_TRACER
 147   ifndef CONFIG_HAVE_FENTRY
 148         ACCUMULATE_OUTGOING_ARGS := 1
 149   else
 150     ifeq ($(call cc-option-yn, -mfentry), n)
 151         ACCUMULATE_OUTGOING_ARGS := 1
 152
 153         # GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
 154         # If '-Os' is enabled, disable it and print a warning.
 155         ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
 156           undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
 157           $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE.  Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
 158         endif
 159
 160     endif
 161   endif
 162 endif
 163
 164 ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
 165         # This compiler flag is not supported by Clang:
 166         KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
 167 endif
 168
 169 # Workaround for a gcc prelease that unfortunately was shipped in a suse release
 170 KBUILD_CFLAGS += -Wno-sign-compare
 171 #
 172 KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
 173
 174 # Avoid indirect branches in kernel to deal with Spectre
 175 ifdef CONFIG_RETPOLINE
 176   KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
 177   # Additionally, avoid generating expensive indirect jumps which
 178   # are subject to retpolines for small number of switch cases.
 179   # clang turns off jump table generation by default when under
 180   # retpoline builds, however, gcc does not for x86. This has
 181   # only been fixed starting from gcc stable version 8.4.0 and
 182   # onwards, but not for older ones. See gcc bug #86952.
 183   ifndef CONFIG_CC_IS_CLANG
 184     KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
 185   endif
 186 endif
 187
 188 KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
 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 # See arch/x86/Kbuild for content of core part of the kernel
 226 core-y += arch/x86/
 227
 228 # drivers-y are linked after core-y
 229 drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
 230 drivers-$(CONFIG_PCI)            += arch/x86/pci/
 231
 232 # must be linked after kernel/
 233 drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/
 234
 235 # suspend and hibernation support
 236 drivers-$(CONFIG_PM) += arch/x86/power/
 237
 238 drivers-$(CONFIG_FB) += arch/x86/video/
 239
 240 ####
 241 # boot loader support. Several targets are kept for legacy purposes
 242
 243 boot := arch/x86/boot
 244
 245 BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 isoimage
 246
 247 PHONY += bzImage $(BOOT_TARGETS)
 248
 249 # Default kernel to build
 250 all: bzImage
 251
 252 # KBUILD_IMAGE specify target image being built
 253 KBUILD_IMAGE := $(boot)/bzImage
 254
 255 bzImage: vmlinux
 256 ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
 257         $(Q)$(MAKE) $(build)=arch/x86/tools posttest
 258 endif
 259         $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
 260         $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
 261         $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
 262
 263 $(BOOT_TARGETS): vmlinux
 264         $(Q)$(MAKE) $(build)=$(boot) $@
 265
 266 PHONY += install bzlilo
 267 install bzlilo:
 268         $(Q)$(MAKE) $(build)=$(boot) $@
 269
 270 PHONY += vdso_install
 271 vdso_install:
 272         $(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
 273
 274 archprepare: checkbin
 275 checkbin:
 276 ifndef CONFIG_CC_HAS_ASM_GOTO
 277         @echo Compiler lacks asm-goto support.
 278         @exit 1
 279 endif
 280 ifdef CONFIG_RETPOLINE
 281 ifeq ($(RETPOLINE_CFLAGS),)
 282         @echo "You are building kernel with non-retpoline compiler." >&2
 283         @echo "Please update your compiler." >&2
 284         @false
 285 endif
 286 endif
 287
 288 archclean:
 289         $(Q)rm -rf $(objtree)/arch/i386
 290         $(Q)rm -rf $(objtree)/arch/x86_64
 291         $(Q)$(MAKE) $(clean)=$(boot)
 292         $(Q)$(MAKE) $(clean)=arch/x86/tools
 293
 294 define archhelp
 295   echo  '* bzImage      - Compressed kernel image (arch/x86/boot/bzImage)'
 296   echo  '  install      - Install kernel using'
 297   echo  '                  (your) ~/bin/$(INSTALLKERNEL) or'
 298   echo  '                  (distribution) /sbin/$(INSTALLKERNEL) or'
 299   echo  '                  install to $$(INSTALL_PATH) and run lilo'
 300   echo  '  fdimage      - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
 301   echo  '  fdimage144   - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
 302   echo  '  fdimage288   - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
 303   echo  '  isoimage     - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
 304   echo  '                  bzdisk/fdimage*/isoimage also accept:'
 305   echo  '                  FDARGS="..."  arguments for the booted kernel'
 306   echo  '                  FDINITRD=file initrd for the booted kernel'
 307 endef