xref: /openbmc/linux/arch/x86/Makefile (revision 31e67366) 
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
31
32REALMODE_CFLAGS += -ffreestanding
33REALMODE_CFLAGS += -fno-stack-protector
34REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member)
35REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
36export REALMODE_CFLAGS
37
38# BITS is used as extension for files which are available in a 32 bit
39# and a 64 bit version to simplify shared Makefiles.
40# e.g.: obj-y += foo_$(BITS).o
41export 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#
50KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
51KBUILD_CFLAGS += $(call cc-option,-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        biarch := $(call cc-option,-m32)
62        KBUILD_AFLAGS += $(biarch)
63        KBUILD_CFLAGS += $(biarch)
64
65        KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
66
67        # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
68        # with nonstandard options
69        KBUILD_CFLAGS += -fno-pic
70
71        # Align the stack to the register width instead of using the default
72        # alignment of 16 bytes. This reduces stack usage and the number of
73        # alignment instructions.
74        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
75
76        # CPU-specific tuning. Anything which can be shared with UML should go here.
77        include arch/x86/Makefile_32.cpu
78        KBUILD_CFLAGS += $(cflags-y)
79
80        # temporary until string.h is fixed
81        KBUILD_CFLAGS += -ffreestanding
82else
83        BITS := 64
84        UTS_MACHINE := x86_64
85        CHECKFLAGS += -D__x86_64__
86
87        biarch := -m64
88        KBUILD_AFLAGS += -m64
89        KBUILD_CFLAGS += -m64
90
91        # Align jump targets to 1 byte, not the default 16 bytes:
92        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
93
94        # Pack loops tightly as well:
95        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
96
97        # Don't autogenerate traditional x87 instructions
98        KBUILD_CFLAGS += $(call cc-option,-mno-80387)
99        KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
100
101        # By default gcc and clang use a stack alignment of 16 bytes for x86.
102        # However the standard kernel entry on x86-64 leaves the stack on an
103        # 8-byte boundary. If the compiler isn't informed about the actual
104        # alignment it will generate extra alignment instructions for the
105        # default alignment which keep the stack *mis*aligned.
106        # Furthermore an alignment to the register width reduces stack usage
107        # and the number of alignment instructions.
108        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
109
110	# Use -mskip-rax-setup if supported.
111	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
112
113        # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
114        cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
115        cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
116
117        cflags-$(CONFIG_MCORE2) += \
118                $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
119	cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
120		$(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
121        cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
122        KBUILD_CFLAGS += $(cflags-y)
123
124        KBUILD_CFLAGS += -mno-red-zone
125        KBUILD_CFLAGS += -mcmodel=kernel
126endif
127
128ifdef CONFIG_X86_X32
129	x32_ld_ok := $(call try-run,\
130			/bin/echo -e '1: .quad 1b' | \
131			$(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
132			$(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMPO" && \
133			$(LD) -m elf32_x86_64 "$$TMPO" -o "$$TMP",y,n)
134        ifeq ($(x32_ld_ok),y)
135                CONFIG_X86_X32_ABI := y
136                KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
137                KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
138        else
139                $(warning CONFIG_X86_X32 enabled but no binutils support)
140        endif
141endif
142export CONFIG_X86_X32_ABI
143
144#
145# If the function graph tracer is used with mcount instead of fentry,
146# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
147# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
148#
149ifdef CONFIG_FUNCTION_GRAPH_TRACER
150  ifndef CONFIG_HAVE_FENTRY
151	ACCUMULATE_OUTGOING_ARGS := 1
152  else
153    ifeq ($(call cc-option-yn, -mfentry), n)
154	ACCUMULATE_OUTGOING_ARGS := 1
155
156	# GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
157	# If '-Os' is enabled, disable it and print a warning.
158        ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
159          undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
160          $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE.  Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
161        endif
162
163    endif
164  endif
165endif
166
167ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
168	# This compiler flag is not supported by Clang:
169	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
170endif
171
172ifdef CONFIG_LTO_CLANG
173KBUILD_LDFLAGS	+= -plugin-opt=-code-model=kernel \
174		   -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
175endif
176
177# Workaround for a gcc prelease that unfortunately was shipped in a suse release
178KBUILD_CFLAGS += -Wno-sign-compare
179#
180KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
181
182# Avoid indirect branches in kernel to deal with Spectre
183ifdef CONFIG_RETPOLINE
184  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
185  # Additionally, avoid generating expensive indirect jumps which
186  # are subject to retpolines for small number of switch cases.
187  # clang turns off jump table generation by default when under
188  # retpoline builds, however, gcc does not for x86. This has
189  # only been fixed starting from gcc stable version 8.4.0 and
190  # onwards, but not for older ones. See gcc bug #86952.
191  ifndef CONFIG_CC_IS_CLANG
192    KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
193  endif
194endif
195
196KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
197
198ifdef CONFIG_X86_NEED_RELOCS
199LDFLAGS_vmlinux := --emit-relocs --discard-none
200else
201LDFLAGS_vmlinux :=
202endif
203
204#
205# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
206# the linker to force 2MB page size regardless of the default page size used
207# by the linker.
208#
209ifdef CONFIG_X86_64
210LDFLAGS_vmlinux += -z max-page-size=0x200000
211endif
212
213
214archscripts: scripts_basic
215	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
216
217###
218# Syscall table generation
219
220archheaders:
221	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
222
223###
224# Kernel objects
225
226head-y := arch/x86/kernel/head_$(BITS).o
227head-y += arch/x86/kernel/head$(BITS).o
228head-y += arch/x86/kernel/ebda.o
229head-y += arch/x86/kernel/platform-quirks.o
230
231libs-y  += arch/x86/lib/
232
233# See arch/x86/Kbuild for content of core part of the kernel
234core-y += arch/x86/
235
236# drivers-y are linked after core-y
237drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
238drivers-$(CONFIG_PCI)            += arch/x86/pci/
239
240# suspend and hibernation support
241drivers-$(CONFIG_PM) += arch/x86/power/
242
243drivers-$(CONFIG_FB) += arch/x86/video/
244
245####
246# boot loader support. Several targets are kept for legacy purposes
247
248boot := arch/x86/boot
249
250BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 isoimage
251
252PHONY += bzImage $(BOOT_TARGETS)
253
254# Default kernel to build
255all: bzImage
256
257# KBUILD_IMAGE specify target image being built
258KBUILD_IMAGE := $(boot)/bzImage
259
260bzImage: vmlinux
261ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
262	$(Q)$(MAKE) $(build)=arch/x86/tools posttest
263endif
264	$(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
265	$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
266	$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
267
268$(BOOT_TARGETS): vmlinux
269	$(Q)$(MAKE) $(build)=$(boot) $@
270
271PHONY += install bzlilo
272install bzlilo:
273	$(Q)$(MAKE) $(build)=$(boot) $@
274
275PHONY += vdso_install
276vdso_install:
277	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
278
279archprepare: checkbin
280checkbin:
281ifndef CONFIG_CC_HAS_ASM_GOTO
282	@echo Compiler lacks asm-goto support.
283	@exit 1
284endif
285ifdef CONFIG_RETPOLINE
286ifeq ($(RETPOLINE_CFLAGS),)
287	@echo "You are building kernel with non-retpoline compiler." >&2
288	@echo "Please update your compiler." >&2
289	@false
290endif
291endif
292
293archclean:
294	$(Q)rm -rf $(objtree)/arch/i386
295	$(Q)rm -rf $(objtree)/arch/x86_64
296	$(Q)$(MAKE) $(clean)=$(boot)
297	$(Q)$(MAKE) $(clean)=arch/x86/tools
298
299define archhelp
300  echo  '* bzImage		- Compressed kernel image (arch/x86/boot/bzImage)'
301  echo  '  install		- Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
302  echo  '			  (distribution) /sbin/$(INSTALLKERNEL) or install to '
303  echo  '			  $$(INSTALL_PATH) and run lilo'
304  echo  ''
305  echo  '  fdimage		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
306  echo  '  fdimage144		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
307  echo  '  fdimage288		- Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
308  echo  '  isoimage		- Create a boot CD-ROM image (arch/x86/boot/image.iso)'
309  echo  '			  bzdisk/fdimage*/isoimage also accept:'
310  echo  '			  FDARGS="..."  arguments for the booted kernel'
311  echo  '                  	  FDINITRD=file initrd for the booted kernel'
312  echo  ''
313  echo  '  kvm_guest.config	- Enable Kconfig items for running this kernel as a KVM guest'
314  echo  '  xen.config		- Enable Kconfig items for running this kernel as a Xen guest'
315
316endef
317