xref: /openbmc/linux/arch/x86/Makefile (revision ae213c44) 
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 ($(call cc-option, -mstack-alignment=16),)
21      cc_stack_align4 := -mstack-alignment=4
22      cc_stack_align8 := -mstack-alignment=8
23endif
24
25# How to compile the 16-bit code.  Note we always compile for -march=i386;
26# that way we can complain to the user if the CPU is insufficient.
27#
28# The -m16 option is supported by GCC >= 4.9 and clang >= 3.5. For
29# older versions of GCC, include an *assembly* header to make sure that
30# gcc doesn't play any games behind our back.
31CODE16GCC_CFLAGS := -m32 -Wa,$(srctree)/arch/x86/boot/code16gcc.h
32M16_CFLAGS	 := $(call cc-option, -m16, $(CODE16GCC_CFLAGS))
33
34REALMODE_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
38
39REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -ffreestanding)
40REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -fno-stack-protector)
41REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
42export REALMODE_CFLAGS
43
44# BITS is used as extension for files which are available in a 32 bit
45# and a 64 bit version to simplify shared Makefiles.
46# e.g.: obj-y += foo_$(BITS).o
47export BITS
48
49ifdef CONFIG_X86_NEED_RELOCS
50        LDFLAGS_vmlinux := --emit-relocs --discard-none
51endif
52
53#
54# Prevent GCC from generating any FP code by mistake.
55#
56# This must happen before we try the -mpreferred-stack-boundary, see:
57#
58#    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
59#
60KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
61KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
62
63ifeq ($(CONFIG_X86_32),y)
64        BITS := 32
65        UTS_MACHINE := i386
66        CHECKFLAGS += -D__i386__
67
68        biarch := $(call cc-option,-m32)
69        KBUILD_AFLAGS += $(biarch)
70        KBUILD_CFLAGS += $(biarch)
71
72        KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
73
74        # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
75        # with nonstandard options
76        KBUILD_CFLAGS += -fno-pic
77
78        # Align the stack to the register width instead of using the default
79        # alignment of 16 bytes. This reduces stack usage and the number of
80        # alignment instructions.
81        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
82
83        # CPU-specific tuning. Anything which can be shared with UML should go here.
84        include arch/x86/Makefile_32.cpu
85        KBUILD_CFLAGS += $(cflags-y)
86
87        # temporary until string.h is fixed
88        KBUILD_CFLAGS += -ffreestanding
89else
90        BITS := 64
91        UTS_MACHINE := x86_64
92        CHECKFLAGS += -D__x86_64__
93
94        biarch := -m64
95        KBUILD_AFLAGS += -m64
96        KBUILD_CFLAGS += -m64
97
98        # Align jump targets to 1 byte, not the default 16 bytes:
99        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
100
101        # Pack loops tightly as well:
102        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
103
104        # Don't autogenerate traditional x87 instructions
105        KBUILD_CFLAGS += $(call cc-option,-mno-80387)
106        KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
107
108        # By default gcc and clang use a stack alignment of 16 bytes for x86.
109        # However the standard kernel entry on x86-64 leaves the stack on an
110        # 8-byte boundary. If the compiler isn't informed about the actual
111        # alignment it will generate extra alignment instructions for the
112        # default alignment which keep the stack *mis*aligned.
113        # Furthermore an alignment to the register width reduces stack usage
114        # and the number of alignment instructions.
115        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
116
117	# Use -mskip-rax-setup if supported.
118	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
119
120        # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
121        cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
122        cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
123
124        cflags-$(CONFIG_MCORE2) += \
125                $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
126	cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
127		$(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
128        cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
129        KBUILD_CFLAGS += $(cflags-y)
130
131        KBUILD_CFLAGS += -mno-red-zone
132        KBUILD_CFLAGS += -mcmodel=kernel
133endif
134
135ifdef CONFIG_X86_X32
136	x32_ld_ok := $(call try-run,\
137			/bin/echo -e '1: .quad 1b' | \
138			$(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
139			$(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMPO" && \
140			$(LD) -m elf32_x86_64 "$$TMPO" -o "$$TMP",y,n)
141        ifeq ($(x32_ld_ok),y)
142                CONFIG_X86_X32_ABI := y
143                KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
144                KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
145        else
146                $(warning CONFIG_X86_X32 enabled but no binutils support)
147        endif
148endif
149export CONFIG_X86_X32_ABI
150
151#
152# If the function graph tracer is used with mcount instead of fentry,
153# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
154# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
155#
156ifdef CONFIG_FUNCTION_GRAPH_TRACER
157  ifndef CONFIG_HAVE_FENTRY
158	ACCUMULATE_OUTGOING_ARGS := 1
159  else
160    ifeq ($(call cc-option-yn, -mfentry), n)
161	ACCUMULATE_OUTGOING_ARGS := 1
162
163	# GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
164	# If '-Os' is enabled, disable it and print a warning.
165        ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
166          undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
167          $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE.  Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
168        endif
169
170    endif
171  endif
172endif
173
174ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
175	# This compiler flag is not supported by Clang:
176	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
177endif
178
179# Stackpointer is addressed different for 32 bit and 64 bit x86
180sp-$(CONFIG_X86_32) := esp
181sp-$(CONFIG_X86_64) := rsp
182
183# do binutils support CFI?
184cfi := $(call as-instr,.cfi_startproc\n.cfi_rel_offset $(sp-y)$(comma)0\n.cfi_endproc,-DCONFIG_AS_CFI=1)
185# is .cfi_signal_frame supported too?
186cfi-sigframe := $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1)
187cfi-sections := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTIONS=1)
188
189# does binutils support specific instructions?
190asinstr += $(call as-instr,pshufb %xmm0$(comma)%xmm0,-DCONFIG_AS_SSSE3=1)
191avx_instr := $(call as-instr,vxorps %ymm0$(comma)%ymm1$(comma)%ymm2,-DCONFIG_AS_AVX=1)
192avx2_instr :=$(call as-instr,vpbroadcastb %xmm0$(comma)%ymm1,-DCONFIG_AS_AVX2=1)
193avx512_instr :=$(call as-instr,vpmovm2b %k1$(comma)%zmm5,-DCONFIG_AS_AVX512=1)
194sha1_ni_instr :=$(call as-instr,sha1msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA1_NI=1)
195sha256_ni_instr :=$(call as-instr,sha256msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA256_NI=1)
196
197KBUILD_AFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr)
198KBUILD_CFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr)
199
200KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
201
202#
203# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
204# the linker to force 2MB page size regardless of the default page size used
205# by the linker.
206#
207ifdef CONFIG_X86_64
208KBUILD_LDFLAGS += $(call ld-option, -z max-page-size=0x200000)
209endif
210
211# Workaround for a gcc prelease that unfortunately was shipped in a suse release
212KBUILD_CFLAGS += -Wno-sign-compare
213#
214KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
215
216# Avoid indirect branches in kernel to deal with Spectre
217ifdef CONFIG_RETPOLINE
218  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
219  # Additionally, avoid generating expensive indirect jumps which
220  # are subject to retpolines for small number of switch cases.
221  # clang turns off jump table generation by default when under
222  # retpoline builds, however, gcc does not for x86. This has
223  # only been fixed starting from gcc stable version 8.4.0 and
224  # onwards, but not for older ones. See gcc bug #86952.
225  ifndef CONFIG_CC_IS_CLANG
226    KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
227  endif
228endif
229
230archscripts: scripts_basic
231	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
232
233###
234# Syscall table generation
235
236archheaders:
237	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
238
239###
240# Kernel objects
241
242head-y := arch/x86/kernel/head_$(BITS).o
243head-y += arch/x86/kernel/head$(BITS).o
244head-y += arch/x86/kernel/ebda.o
245head-y += arch/x86/kernel/platform-quirks.o
246
247libs-y  += arch/x86/lib/
248
249# See arch/x86/Kbuild for content of core part of the kernel
250core-y += arch/x86/
251
252# drivers-y are linked after core-y
253drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
254drivers-$(CONFIG_PCI)            += arch/x86/pci/
255
256# must be linked after kernel/
257drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/
258
259# suspend and hibernation support
260drivers-$(CONFIG_PM) += arch/x86/power/
261
262drivers-$(CONFIG_FB) += arch/x86/video/
263
264####
265# boot loader support. Several targets are kept for legacy purposes
266
267boot := arch/x86/boot
268
269BOOT_TARGETS = bzlilo bzdisk fdimage fdimage144 fdimage288 isoimage
270
271PHONY += bzImage $(BOOT_TARGETS)
272
273# Default kernel to build
274all: bzImage
275
276# KBUILD_IMAGE specify target image being built
277KBUILD_IMAGE := $(boot)/bzImage
278
279bzImage: vmlinux
280ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
281	$(Q)$(MAKE) $(build)=arch/x86/tools posttest
282endif
283	$(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
284	$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
285	$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
286
287$(BOOT_TARGETS): vmlinux
288	$(Q)$(MAKE) $(build)=$(boot) $@
289
290PHONY += install
291install:
292	$(Q)$(MAKE) $(build)=$(boot) $@
293
294PHONY += vdso_install
295vdso_install:
296	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
297
298archprepare: checkbin
299checkbin:
300ifndef CONFIG_CC_HAS_ASM_GOTO
301	@echo Compiler lacks asm-goto support.
302	@exit 1
303endif
304ifdef CONFIG_RETPOLINE
305ifeq ($(RETPOLINE_CFLAGS),)
306	@echo "You are building kernel with non-retpoline compiler." >&2
307	@echo "Please update your compiler." >&2
308	@false
309endif
310endif
311
312archclean:
313	$(Q)rm -rf $(objtree)/arch/i386
314	$(Q)rm -rf $(objtree)/arch/x86_64
315	$(Q)$(MAKE) $(clean)=$(boot)
316	$(Q)$(MAKE) $(clean)=arch/x86/tools
317
318define archhelp
319  echo  '* bzImage      - Compressed kernel image (arch/x86/boot/bzImage)'
320  echo  '  install      - Install kernel using'
321  echo  '                  (your) ~/bin/$(INSTALLKERNEL) or'
322  echo  '                  (distribution) /sbin/$(INSTALLKERNEL) or'
323  echo  '                  install to $$(INSTALL_PATH) and run lilo'
324  echo  '  fdimage      - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
325  echo  '  fdimage144   - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
326  echo  '  fdimage288   - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
327  echo  '  isoimage     - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
328  echo  '                  bzdisk/fdimage*/isoimage also accept:'
329  echo  '                  FDARGS="..."  arguments for the booted kernel'
330  echo  '                  FDINITRD=file initrd for the booted kernel'
331endef
332