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 += -Wno-address-of-packed-member
35REALMODE_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 -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        KBUILD_AFLAGS += -m32
62        KBUILD_CFLAGS += -m32
63
64        KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
65
66        # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
67        # with nonstandard options
68        KBUILD_CFLAGS += -fno-pic
69
70        # Align the stack to the register width instead of using the default
71        # alignment of 16 bytes. This reduces stack usage and the number of
72        # alignment instructions.
73        KBUILD_CFLAGS += $(cc_stack_align4)
74
75        # CPU-specific tuning. Anything which can be shared with UML should go here.
76        include $(srctree)/arch/x86/Makefile_32.cpu
77        KBUILD_CFLAGS += $(cflags-y)
78
79        # temporary until string.h is fixed
80        KBUILD_CFLAGS += -ffreestanding
81
82	ifeq ($(CONFIG_STACKPROTECTOR),y)
83		ifeq ($(CONFIG_SMP),y)
84			KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard
85		else
86			KBUILD_CFLAGS += -mstack-protector-guard=global
87		endif
88	endif
89else
90        BITS := 64
91        UTS_MACHINE := x86_64
92        CHECKFLAGS += -D__x86_64__
93
94        KBUILD_AFLAGS += -m64
95        KBUILD_CFLAGS += -m64
96
97        # Align jump targets to 1 byte, not the default 16 bytes:
98        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
99
100        # Pack loops tightly as well:
101        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
102
103        # Don't autogenerate traditional x87 instructions
104        KBUILD_CFLAGS += -mno-80387
105        KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
106
107        # By default gcc and clang use a stack alignment of 16 bytes for x86.
108        # However the standard kernel entry on x86-64 leaves the stack on an
109        # 8-byte boundary. If the compiler isn't informed about the actual
110        # alignment it will generate extra alignment instructions for the
111        # default alignment which keep the stack *mis*aligned.
112        # Furthermore an alignment to the register width reduces stack usage
113        # and the number of alignment instructions.
114        KBUILD_CFLAGS += $(cc_stack_align8)
115
116	# Use -mskip-rax-setup if supported.
117	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
118
119        # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
120        cflags-$(CONFIG_MK8)		+= -march=k8
121        cflags-$(CONFIG_MPSC)		+= -march=nocona
122        cflags-$(CONFIG_MCORE2)		+= -march=core2
123        cflags-$(CONFIG_MATOM)		+= -march=atom
124        cflags-$(CONFIG_GENERIC_CPU)	+= -mtune=generic
125        KBUILD_CFLAGS += $(cflags-y)
126
127        KBUILD_CFLAGS += -mno-red-zone
128        KBUILD_CFLAGS += -mcmodel=kernel
129endif
130
131ifdef CONFIG_X86_X32
132	x32_ld_ok := $(call try-run,\
133			/bin/echo -e '1: .quad 1b' | \
134			$(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
135			$(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMP.o" && \
136			$(LD) -m elf32_x86_64 "$$TMP.o" -o "$$TMP",y,n)
137        ifeq ($(x32_ld_ok),y)
138                CONFIG_X86_X32_ABI := y
139                KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
140                KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
141        else
142                $(warning CONFIG_X86_X32 enabled but no binutils support)
143        endif
144endif
145export CONFIG_X86_X32_ABI
146
147#
148# If the function graph tracer is used with mcount instead of fentry,
149# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
150# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
151#
152ifdef CONFIG_FUNCTION_GRAPH_TRACER
153  ifndef CONFIG_HAVE_FENTRY
154	ACCUMULATE_OUTGOING_ARGS := 1
155  endif
156endif
157
158ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
159	# This compiler flag is not supported by Clang:
160	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
161endif
162
163# Workaround for a gcc prelease that unfortunately was shipped in a suse release
164KBUILD_CFLAGS += -Wno-sign-compare
165#
166KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
167
168# Avoid indirect branches in kernel to deal with Spectre
169ifdef CONFIG_RETPOLINE
170  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
171  # Additionally, avoid generating expensive indirect jumps which
172  # are subject to retpolines for small number of switch cases.
173  # clang turns off jump table generation by default when under
174  # retpoline builds, however, gcc does not for x86. This has
175  # only been fixed starting from gcc stable version 8.4.0 and
176  # onwards, but not for older ones. See gcc bug #86952.
177  ifndef CONFIG_CC_IS_CLANG
178    KBUILD_CFLAGS += -fno-jump-tables
179  endif
180endif
181
182KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
183
184ifdef CONFIG_LTO_CLANG
185ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
186KBUILD_LDFLAGS	+= -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
187endif
188endif
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$(BITS).o
220head-y += arch/x86/kernel/ebda.o
221head-y += arch/x86/kernel/platform-quirks.o
222
223libs-y  += arch/x86/lib/
224
225# drivers-y are linked after core-y
226drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
227drivers-$(CONFIG_PCI)            += arch/x86/pci/
228
229# suspend and hibernation support
230drivers-$(CONFIG_PM) += arch/x86/power/
231
232drivers-$(CONFIG_FB) += arch/x86/video/
233
234####
235# boot loader support. Several targets are kept for legacy purposes
236
237boot := arch/x86/boot
238
239BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
240
241PHONY += bzImage $(BOOT_TARGETS)
242
243# Default kernel to build
244all: bzImage
245
246# KBUILD_IMAGE specify target image being built
247KBUILD_IMAGE := $(boot)/bzImage
248
249bzImage: vmlinux
250ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
251	$(Q)$(MAKE) $(build)=arch/x86/tools posttest
252endif
253	$(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
254	$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
255	$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
256
257$(BOOT_TARGETS): vmlinux
258	$(Q)$(MAKE) $(build)=$(boot) $@
259
260PHONY += install
261install:
262	$(CONFIG_SHELL) $(srctree)/$(boot)/install.sh $(KERNELRELEASE) \
263		$(KBUILD_IMAGE) System.map "$(INSTALL_PATH)"
264
265PHONY += vdso_install
266vdso_install:
267	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
268
269archprepare: checkbin
270checkbin:
271ifndef CONFIG_CC_HAS_ASM_GOTO
272	@echo Compiler lacks asm-goto support.
273	@exit 1
274endif
275ifdef CONFIG_RETPOLINE
276ifeq ($(RETPOLINE_CFLAGS),)
277	@echo "You are building kernel with non-retpoline compiler." >&2
278	@echo "Please update your compiler." >&2
279	@false
280endif
281endif
282
283archclean:
284	$(Q)rm -rf $(objtree)/arch/i386
285	$(Q)rm -rf $(objtree)/arch/x86_64
286
287define archhelp
288  echo  '* bzImage		- Compressed kernel image (arch/x86/boot/bzImage)'
289  echo  '  install		- Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
290  echo  '			  (distribution) /sbin/$(INSTALLKERNEL) or install to '
291  echo  '			  $$(INSTALL_PATH) and run lilo'
292  echo  ''
293  echo  '  fdimage		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
294  echo  '  fdimage144		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
295  echo  '  fdimage288		- Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
296  echo  '  hdimage		- Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
297  echo  '  isoimage		- Create a boot CD-ROM image (arch/x86/boot/image.iso)'
298  echo  '			  bzdisk/fdimage*/hdimage/isoimage also accept:'
299  echo  '			  FDARGS="..."  arguments for the booted kernel'
300  echo  '			  FDINITRD=file initrd for the booted kernel'
301  echo  ''
302  echo  '  kvm_guest.config	- Enable Kconfig items for running this kernel as a KVM guest'
303  echo  '  xen.config		- Enable Kconfig items for running this kernel as a Xen guest'
304
305endef
306