xref: /openbmc/linux/arch/x86/Makefile (revision 249592bf) 
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 $(call cc-option,-fcf-protection=none)
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))
36REALMODE_CFLAGS += $(CLANG_FLAGS)
37export REALMODE_CFLAGS
38
39# BITS is used as extension for files which are available in a 32 bit
40# and a 64 bit version to simplify shared Makefiles.
41# e.g.: obj-y += foo_$(BITS).o
42export BITS
43
44#
45# Prevent GCC from generating any FP code by mistake.
46#
47# This must happen before we try the -mpreferred-stack-boundary, see:
48#
49#    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
50#
51KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
52KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
53
54# Intel CET isn't enabled in the kernel
55KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
56
57ifeq ($(CONFIG_X86_32),y)
58        BITS := 32
59        UTS_MACHINE := i386
60        CHECKFLAGS += -D__i386__
61
62        biarch := $(call cc-option,-m32)
63        KBUILD_AFLAGS += $(biarch)
64        KBUILD_CFLAGS += $(biarch)
65
66        KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
67
68        # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
69        # with nonstandard options
70        KBUILD_CFLAGS += -fno-pic
71
72        # Align the stack to the register width instead of using the default
73        # alignment of 16 bytes. This reduces stack usage and the number of
74        # alignment instructions.
75        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
76
77        # CPU-specific tuning. Anything which can be shared with UML should go here.
78        include arch/x86/Makefile_32.cpu
79        KBUILD_CFLAGS += $(cflags-y)
80
81        # temporary until string.h is fixed
82        KBUILD_CFLAGS += -ffreestanding
83
84	ifeq ($(CONFIG_STACKPROTECTOR),y)
85		ifeq ($(CONFIG_SMP),y)
86			KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard
87		else
88			KBUILD_CFLAGS += -mstack-protector-guard=global
89		endif
90	endif
91else
92        BITS := 64
93        UTS_MACHINE := x86_64
94        CHECKFLAGS += -D__x86_64__
95
96        biarch := -m64
97        KBUILD_AFLAGS += -m64
98        KBUILD_CFLAGS += -m64
99
100        # Align jump targets to 1 byte, not the default 16 bytes:
101        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
102
103        # Pack loops tightly as well:
104        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
105
106        # Don't autogenerate traditional x87 instructions
107        KBUILD_CFLAGS += $(call cc-option,-mno-80387)
108        KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
109
110        # By default gcc and clang use a stack alignment of 16 bytes for x86.
111        # However the standard kernel entry on x86-64 leaves the stack on an
112        # 8-byte boundary. If the compiler isn't informed about the actual
113        # alignment it will generate extra alignment instructions for the
114        # default alignment which keep the stack *mis*aligned.
115        # Furthermore an alignment to the register width reduces stack usage
116        # and the number of alignment instructions.
117        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
118
119	# Use -mskip-rax-setup if supported.
120	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
121
122        # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
123        cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
124        cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
125
126        cflags-$(CONFIG_MCORE2) += \
127                $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
128	cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
129		$(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
130        cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
131        KBUILD_CFLAGS += $(cflags-y)
132
133        KBUILD_CFLAGS += -mno-red-zone
134        KBUILD_CFLAGS += -mcmodel=kernel
135endif
136
137ifdef CONFIG_X86_X32
138	x32_ld_ok := $(call try-run,\
139			/bin/echo -e '1: .quad 1b' | \
140			$(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
141			$(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMP.o" && \
142			$(LD) -m elf32_x86_64 "$$TMP.o" -o "$$TMP",y,n)
143        ifeq ($(x32_ld_ok),y)
144                CONFIG_X86_X32_ABI := y
145                KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
146                KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
147        else
148                $(warning CONFIG_X86_X32 enabled but no binutils support)
149        endif
150endif
151export CONFIG_X86_X32_ABI
152
153#
154# If the function graph tracer is used with mcount instead of fentry,
155# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
156# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
157#
158ifdef CONFIG_FUNCTION_GRAPH_TRACER
159  ifndef CONFIG_HAVE_FENTRY
160	ACCUMULATE_OUTGOING_ARGS := 1
161  else
162    ifeq ($(call cc-option-yn, -mfentry), n)
163	ACCUMULATE_OUTGOING_ARGS := 1
164
165	# GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
166	# If '-Os' is enabled, disable it and print a warning.
167        ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
168          undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
169          $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE.  Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
170        endif
171
172    endif
173  endif
174endif
175
176ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
177	# This compiler flag is not supported by Clang:
178	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
179endif
180
181ifdef CONFIG_LTO_CLANG
182KBUILD_LDFLAGS	+= -plugin-opt=-code-model=kernel \
183		   -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
184endif
185
186# Workaround for a gcc prelease that unfortunately was shipped in a suse release
187KBUILD_CFLAGS += -Wno-sign-compare
188#
189KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
190
191# Avoid indirect branches in kernel to deal with Spectre
192ifdef CONFIG_RETPOLINE
193  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
194  # Additionally, avoid generating expensive indirect jumps which
195  # are subject to retpolines for small number of switch cases.
196  # clang turns off jump table generation by default when under
197  # retpoline builds, however, gcc does not for x86. This has
198  # only been fixed starting from gcc stable version 8.4.0 and
199  # onwards, but not for older ones. See gcc bug #86952.
200  ifndef CONFIG_CC_IS_CLANG
201    KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
202  endif
203endif
204
205KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
206
207ifdef CONFIG_X86_NEED_RELOCS
208LDFLAGS_vmlinux := --emit-relocs --discard-none
209else
210LDFLAGS_vmlinux :=
211endif
212
213#
214# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
215# the linker to force 2MB page size regardless of the default page size used
216# by the linker.
217#
218ifdef CONFIG_X86_64
219LDFLAGS_vmlinux += -z max-page-size=0x200000
220endif
221
222
223archscripts: scripts_basic
224	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
225
226###
227# Syscall table generation
228
229archheaders:
230	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
231
232###
233# Kernel objects
234
235head-y := arch/x86/kernel/head_$(BITS).o
236head-y += arch/x86/kernel/head$(BITS).o
237head-y += arch/x86/kernel/ebda.o
238head-y += arch/x86/kernel/platform-quirks.o
239
240libs-y  += arch/x86/lib/
241
242# See arch/x86/Kbuild for content of core part of the kernel
243core-y += arch/x86/
244
245# drivers-y are linked after core-y
246drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
247drivers-$(CONFIG_PCI)            += arch/x86/pci/
248
249# suspend and hibernation support
250drivers-$(CONFIG_PM) += arch/x86/power/
251
252drivers-$(CONFIG_FB) += arch/x86/video/
253
254####
255# boot loader support. Several targets are kept for legacy purposes
256
257boot := arch/x86/boot
258
259BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 isoimage
260
261PHONY += bzImage $(BOOT_TARGETS)
262
263# Default kernel to build
264all: bzImage
265
266# KBUILD_IMAGE specify target image being built
267KBUILD_IMAGE := $(boot)/bzImage
268
269bzImage: vmlinux
270ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
271	$(Q)$(MAKE) $(build)=arch/x86/tools posttest
272endif
273	$(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
274	$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
275	$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
276
277$(BOOT_TARGETS): vmlinux
278	$(Q)$(MAKE) $(build)=$(boot) $@
279
280PHONY += install bzlilo
281install bzlilo:
282	$(Q)$(MAKE) $(build)=$(boot) $@
283
284PHONY += vdso_install
285vdso_install:
286	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
287
288archprepare: checkbin
289checkbin:
290ifndef CONFIG_CC_HAS_ASM_GOTO
291	@echo Compiler lacks asm-goto support.
292	@exit 1
293endif
294ifdef CONFIG_RETPOLINE
295ifeq ($(RETPOLINE_CFLAGS),)
296	@echo "You are building kernel with non-retpoline compiler." >&2
297	@echo "Please update your compiler." >&2
298	@false
299endif
300endif
301
302archclean:
303	$(Q)rm -rf $(objtree)/arch/i386
304	$(Q)rm -rf $(objtree)/arch/x86_64
305	$(Q)$(MAKE) $(clean)=$(boot)
306	$(Q)$(MAKE) $(clean)=arch/x86/tools
307
308define archhelp
309  echo  '* bzImage		- Compressed kernel image (arch/x86/boot/bzImage)'
310  echo  '  install		- Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
311  echo  '			  (distribution) /sbin/$(INSTALLKERNEL) or install to '
312  echo  '			  $$(INSTALL_PATH) and run lilo'
313  echo  ''
314  echo  '  fdimage		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
315  echo  '  fdimage144		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
316  echo  '  fdimage288		- Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
317  echo  '  isoimage		- Create a boot CD-ROM image (arch/x86/boot/image.iso)'
318  echo  '			  bzdisk/fdimage*/isoimage also accept:'
319  echo  '			  FDARGS="..."  arguments for the booted kernel'
320  echo  '                  	  FDINITRD=file initrd for the booted kernel'
321  echo  ''
322  echo  '  kvm_guest.config	- Enable Kconfig items for running this kernel as a KVM guest'
323  echo  '  xen.config		- Enable Kconfig items for running this kernel as a Xen guest'
324
325endef
326