1 # SPDX-License-Identifier: GPL-2.0
2 # Unified Makefile for i386 and x86_64
4 # select defconfig based on actual architecture
6 ifeq ($(shell uname -m),x86_64)
7 KBUILD_DEFCONFIG := x86_64_defconfig
9 KBUILD_DEFCONFIG := i386_defconfig
12 KBUILD_DEFCONFIG := $(ARCH)_defconfig
15 # For gcc stack alignment is specified with -mpreferred-stack-boundary,
16 # clang has the option -mstack-alignment for that purpose.
17 ifneq ($(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 ($(call cc-option, -mstack-alignment=16),)
21 cc_stack_align4 := -mstack-alignment=4
22 cc_stack_align8 := -mstack-alignment=8
25 # How to compile the 16-bit code. Note we always compile for -march=i386;
26 # that way we can complain to the user if the CPU is insufficient.
28 # The -m16 option is supported by GCC >= 4.9 and clang >= 3.5. For
29 # older versions of GCC, include an *assembly* header to make sure that
30 # gcc doesn't play any games behind our back.
31 CODE16GCC_CFLAGS := -m32 -Wa,$(srctree)/arch/x86/boot/code16gcc.h
32 M16_CFLAGS := $(call cc-option, -m16, $(CODE16GCC_CFLAGS))
34 REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -DDISABLE_BRANCH_PROFILING \
35 -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
36 -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
37 -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none)
39 REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -ffreestanding)
40 REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -fno-stack-protector)
41 REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member)
42 REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
43 REALMODE_CFLAGS += $(CLANG_FLAGS)
44 export REALMODE_CFLAGS
46 # BITS is used as extension for files which are available in a 32 bit
47 # and a 64 bit version to simplify shared Makefiles.
48 # e.g.: obj-y += foo_$(BITS).o
51 ifdef CONFIG_X86_NEED_RELOCS
52 LDFLAGS_vmlinux := --emit-relocs --discard-none
56 # Prevent GCC from generating any FP code by mistake.
58 # This must happen before we try the -mpreferred-stack-boundary, see:
60 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
62 KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
63 KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
65 # Intel CET isn't enabled in the kernel
66 KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
68 ifeq ($(CONFIG_X86_32),y)
71 CHECKFLAGS += -D__i386__
73 biarch := $(call cc-option,-m32)
74 KBUILD_AFLAGS += $(biarch)
75 KBUILD_CFLAGS += $(biarch)
77 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
79 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
80 # with nonstandard options
81 KBUILD_CFLAGS += -fno-pic
83 # Align the stack to the register width instead of using the default
84 # alignment of 16 bytes. This reduces stack usage and the number of
85 # alignment instructions.
86 KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
88 # CPU-specific tuning. Anything which can be shared with UML should go here.
89 include arch/x86/Makefile_32.cpu
90 KBUILD_CFLAGS += $(cflags-y)
92 # temporary until string.h is fixed
93 KBUILD_CFLAGS += -ffreestanding
97 CHECKFLAGS += -D__x86_64__
100 KBUILD_AFLAGS += -m64
101 KBUILD_CFLAGS += -m64
103 # Align jump targets to 1 byte, not the default 16 bytes:
104 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
106 # Pack loops tightly as well:
107 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
109 # Don't autogenerate traditional x87 instructions
110 KBUILD_CFLAGS += $(call cc-option,-mno-80387)
111 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
113 # By default gcc and clang use a stack alignment of 16 bytes for x86.
114 # However the standard kernel entry on x86-64 leaves the stack on an
115 # 8-byte boundary. If the compiler isn't informed about the actual
116 # alignment it will generate extra alignment instructions for the
117 # default alignment which keep the stack *mis*aligned.
118 # Furthermore an alignment to the register width reduces stack usage
119 # and the number of alignment instructions.
120 KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
122 # Use -mskip-rax-setup if supported.
123 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
125 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
126 cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
127 cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
129 cflags-$(CONFIG_MCORE2) += \
130 $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
131 cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
132 $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
133 cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
134 KBUILD_CFLAGS += $(cflags-y)
136 KBUILD_CFLAGS += -mno-red-zone
137 KBUILD_CFLAGS += -mcmodel=kernel
141 x32_ld_ok := $(call try-run,\
142 /bin/echo -e '1: .quad 1b' | \
143 $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
144 $(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMPO" && \
145 $(LD) -m elf32_x86_64 "$$TMPO" -o "$$TMP",y,n)
146 ifeq ($(x32_ld_ok),y)
147 CONFIG_X86_X32_ABI := y
148 KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
149 KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
151 $(warning CONFIG_X86_X32 enabled but no binutils support)
154 export CONFIG_X86_X32_ABI
157 # If the function graph tracer is used with mcount instead of fentry,
158 # '-maccumulate-outgoing-args' is needed to prevent a GCC bug
159 # (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
161 ifdef CONFIG_FUNCTION_GRAPH_TRACER
162 ifndef CONFIG_HAVE_FENTRY
163 ACCUMULATE_OUTGOING_ARGS := 1
165 ifeq ($(call cc-option-yn, -mfentry), n)
166 ACCUMULATE_OUTGOING_ARGS := 1
168 # GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
169 # If '-Os' is enabled, disable it and print a warning.
170 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
171 undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
172 $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE. Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
179 ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
180 # This compiler flag is not supported by Clang:
181 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
184 # Stackpointer is addressed different for 32 bit and 64 bit x86
185 sp-$(CONFIG_X86_32) := esp
186 sp-$(CONFIG_X86_64) := rsp
188 # do binutils support CFI?
189 cfi := $(call as-instr,.cfi_startproc\n.cfi_rel_offset $(sp-y)$(comma)0\n.cfi_endproc,-DCONFIG_AS_CFI=1)
190 # is .cfi_signal_frame supported too?
191 cfi-sigframe := $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1)
192 cfi-sections := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTIONS=1)
194 # does binutils support specific instructions?
195 asinstr += $(call as-instr,pshufb %xmm0$(comma)%xmm0,-DCONFIG_AS_SSSE3=1)
196 avx_instr := $(call as-instr,vxorps %ymm0$(comma)%ymm1$(comma)%ymm2,-DCONFIG_AS_AVX=1)
197 avx2_instr :=$(call as-instr,vpbroadcastb %xmm0$(comma)%ymm1,-DCONFIG_AS_AVX2=1)
198 avx512_instr :=$(call as-instr,vpmovm2b %k1$(comma)%zmm5,-DCONFIG_AS_AVX512=1)
199 sha1_ni_instr :=$(call as-instr,sha1msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA1_NI=1)
200 sha256_ni_instr :=$(call as-instr,sha256msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA256_NI=1)
202 KBUILD_AFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr)
203 KBUILD_CFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr)
205 KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
208 # The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to
209 # the linker to force 2MB page size regardless of the default page size used
213 KBUILD_LDFLAGS += $(call ld-option, -z max-page-size=0x200000)
216 # Workaround for a gcc prelease that unfortunately was shipped in a suse release
217 KBUILD_CFLAGS += -Wno-sign-compare
219 KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
221 # Avoid indirect branches in kernel to deal with Spectre
222 ifdef CONFIG_RETPOLINE
223 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
224 # Additionally, avoid generating expensive indirect jumps which
225 # are subject to retpolines for small number of switch cases.
226 # clang turns off jump table generation by default when under
227 # retpoline builds, however, gcc does not for x86. This has
228 # only been fixed starting from gcc stable version 8.4.0 and
229 # onwards, but not for older ones. See gcc bug #86952.
230 ifndef CONFIG_CC_IS_CLANG
231 KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
235 archscripts: scripts_basic
236 $(Q)$(MAKE) $(build)=arch/x86/tools relocs
239 # Syscall table generation
242 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
247 head-y := arch/x86/kernel/head_$(BITS).o
248 head-y += arch/x86/kernel/head$(BITS).o
249 head-y += arch/x86/kernel/ebda.o
250 head-y += arch/x86/kernel/platform-quirks.o
252 libs-y += arch/x86/lib/
254 # See arch/x86/Kbuild for content of core part of the kernel
257 # drivers-y are linked after core-y
258 drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
259 drivers-$(CONFIG_PCI) += arch/x86/pci/
261 # must be linked after kernel/
262 drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/
264 # suspend and hibernation support
265 drivers-$(CONFIG_PM) += arch/x86/power/
267 drivers-$(CONFIG_FB) += arch/x86/video/
270 # boot loader support. Several targets are kept for legacy purposes
272 boot := arch/x86/boot
274 BOOT_TARGETS = bzlilo bzdisk fdimage fdimage144 fdimage288 isoimage
276 PHONY += bzImage $(BOOT_TARGETS)
278 # Default kernel to build
281 # KBUILD_IMAGE specify target image being built
282 KBUILD_IMAGE := $(boot)/bzImage
285 ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
286 $(Q)$(MAKE) $(build)=arch/x86/tools posttest
288 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
289 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
290 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
292 $(BOOT_TARGETS): vmlinux
293 $(Q)$(MAKE) $(build)=$(boot) $@
297 $(Q)$(MAKE) $(build)=$(boot) $@
299 PHONY += vdso_install
301 $(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
303 archprepare: checkbin
305 ifndef CONFIG_CC_HAS_ASM_GOTO
306 @echo Compiler lacks asm-goto support.
309 ifdef CONFIG_RETPOLINE
310 ifeq ($(RETPOLINE_CFLAGS),)
311 @echo "You are building kernel with non-retpoline compiler." >&2
312 @echo "Please update your compiler." >&2
318 $(Q)rm -rf $(objtree)/arch/i386
319 $(Q)rm -rf $(objtree)/arch/x86_64
320 $(Q)$(MAKE) $(clean)=$(boot)
321 $(Q)$(MAKE) $(clean)=arch/x86/tools
324 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)'
325 echo ' install - Install kernel using'
326 echo ' (your) ~/bin/$(INSTALLKERNEL) or'
327 echo ' (distribution) /sbin/$(INSTALLKERNEL) or'
328 echo ' install to $$(INSTALL_PATH) and run lilo'
329 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
330 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
331 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
332 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
333 echo ' bzdisk/fdimage*/isoimage also accept:'
334 echo ' FDARGS="..." arguments for the booted kernel'
335 echo ' FDINITRD=file initrd for the booted kernel'