xref: /openbmc/linux/arch/x86/Makefile (revision dfe94d40) 
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 += $(call cc-option,-mno-avx,)
52
53ifeq ($(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
79else
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
123endif
124
125ifdef 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
138endif
139export 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#
146ifdef 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
162endif
163
164ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
165	# This compiler flag is not supported by Clang:
166	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
167endif
168
169# Workaround for a gcc prelease that unfortunately was shipped in a suse release
170KBUILD_CFLAGS += -Wno-sign-compare
171#
172KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
173
174# Avoid indirect branches in kernel to deal with Spectre
175ifdef 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
186endif
187
188KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
189
190ifdef CONFIG_X86_NEED_RELOCS
191LDFLAGS_vmlinux := --emit-relocs --discard-none
192else
193LDFLAGS_vmlinux :=
194endif
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#
201ifdef CONFIG_X86_64
202LDFLAGS_vmlinux += -z max-page-size=0x200000
203endif
204
205
206archscripts: scripts_basic
207	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
208
209###
210# Syscall table generation
211
212archheaders:
213	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
214
215###
216# Kernel objects
217
218head-y := arch/x86/kernel/head_$(BITS).o
219head-y += arch/x86/kernel/head$(BITS).o
220head-y += arch/x86/kernel/ebda.o
221head-y += arch/x86/kernel/platform-quirks.o
222
223libs-y  += arch/x86/lib/
224
225# See arch/x86/Kbuild for content of core part of the kernel
226core-y += arch/x86/
227
228# drivers-y are linked after core-y
229drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
230drivers-$(CONFIG_PCI)            += arch/x86/pci/
231
232# must be linked after kernel/
233drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/
234
235# suspend and hibernation support
236drivers-$(CONFIG_PM) += arch/x86/power/
237
238drivers-$(CONFIG_FB) += arch/x86/video/
239
240####
241# boot loader support. Several targets are kept for legacy purposes
242
243boot := arch/x86/boot
244
245BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 isoimage
246
247PHONY += bzImage $(BOOT_TARGETS)
248
249# Default kernel to build
250all: bzImage
251
252# KBUILD_IMAGE specify target image being built
253KBUILD_IMAGE := $(boot)/bzImage
254
255bzImage: vmlinux
256ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
257	$(Q)$(MAKE) $(build)=arch/x86/tools posttest
258endif
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
266PHONY += install bzlilo
267install bzlilo:
268	$(Q)$(MAKE) $(build)=$(boot) $@
269
270PHONY += vdso_install
271vdso_install:
272	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
273
274archprepare: checkbin
275checkbin:
276ifndef CONFIG_CC_HAS_ASM_GOTO
277	@echo Compiler lacks asm-goto support.
278	@exit 1
279endif
280ifdef CONFIG_RETPOLINE
281ifeq ($(RETPOLINE_CFLAGS),)
282	@echo "You are building kernel with non-retpoline compiler." >&2
283	@echo "Please update your compiler." >&2
284	@false
285endif
286endif
287
288archclean:
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
294define 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'
307endef
308