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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 -D__DISABLE_EXPORTS \
35		   -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
36		   -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
37		   -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none)
38
39REALMODE_CFLAGS += -ffreestanding
40REALMODE_CFLAGS += -fno-stack-protector
41REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member)
42REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
43REALMODE_CFLAGS += $(CLANG_FLAGS)
44export REALMODE_CFLAGS
45
46# BITS is used as extension for files which are available in a 32 bit
47# and a 64 bit version to simplify shared Makefiles.
48# e.g.: obj-y += foo_$(BITS).o
49export BITS
50
51#
52# Prevent GCC from generating any FP code by mistake.
53#
54# This must happen before we try the -mpreferred-stack-boundary, see:
55#
56#    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
57#
58KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
59KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
60
61# Intel CET isn't enabled in the kernel
62KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
63
64ifeq ($(CONFIG_X86_32),y)
65        BITS := 32
66        UTS_MACHINE := i386
67        CHECKFLAGS += -D__i386__
68
69        biarch := $(call cc-option,-m32)
70        KBUILD_AFLAGS += $(biarch)
71        KBUILD_CFLAGS += $(biarch)
72
73        KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
74
75        # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
76        # with nonstandard options
77        KBUILD_CFLAGS += -fno-pic
78
79        # Align the stack to the register width instead of using the default
80        # alignment of 16 bytes. This reduces stack usage and the number of
81        # alignment instructions.
82        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
83
84        # CPU-specific tuning. Anything which can be shared with UML should go here.
85        include arch/x86/Makefile_32.cpu
86        KBUILD_CFLAGS += $(cflags-y)
87
88        # temporary until string.h is fixed
89        KBUILD_CFLAGS += -ffreestanding
90else
91        BITS := 64
92        UTS_MACHINE := x86_64
93        CHECKFLAGS += -D__x86_64__
94
95        biarch := -m64
96        KBUILD_AFLAGS += -m64
97        KBUILD_CFLAGS += -m64
98
99        # Align jump targets to 1 byte, not the default 16 bytes:
100        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
101
102        # Pack loops tightly as well:
103        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
104
105        # Don't autogenerate traditional x87 instructions
106        KBUILD_CFLAGS += $(call cc-option,-mno-80387)
107        KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
108
109        # By default gcc and clang use a stack alignment of 16 bytes for x86.
110        # However the standard kernel entry on x86-64 leaves the stack on an
111        # 8-byte boundary. If the compiler isn't informed about the actual
112        # alignment it will generate extra alignment instructions for the
113        # default alignment which keep the stack *mis*aligned.
114        # Furthermore an alignment to the register width reduces stack usage
115        # and the number of alignment instructions.
116        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
117
118	# Use -mskip-rax-setup if supported.
119	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
120
121        # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
122        cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
123        cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
124
125        cflags-$(CONFIG_MCORE2) += \
126                $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
127	cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
128		$(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
129        cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
130        KBUILD_CFLAGS += $(cflags-y)
131
132        KBUILD_CFLAGS += -mno-red-zone
133        KBUILD_CFLAGS += -mcmodel=kernel
134endif
135
136ifdef CONFIG_X86_X32
137	x32_ld_ok := $(call try-run,\
138			/bin/echo -e '1: .quad 1b' | \
139			$(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
140			$(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMPO" && \
141			$(LD) -m elf32_x86_64 "$$TMPO" -o "$$TMP",y,n)
142        ifeq ($(x32_ld_ok),y)
143                CONFIG_X86_X32_ABI := y
144                KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
145                KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
146        else
147                $(warning CONFIG_X86_X32 enabled but no binutils support)
148        endif
149endif
150export CONFIG_X86_X32_ABI
151
152#
153# If the function graph tracer is used with mcount instead of fentry,
154# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
155# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
156#
157ifdef CONFIG_FUNCTION_GRAPH_TRACER
158  ifndef CONFIG_HAVE_FENTRY
159	ACCUMULATE_OUTGOING_ARGS := 1
160  else
161    ifeq ($(call cc-option-yn, -mfentry), n)
162	ACCUMULATE_OUTGOING_ARGS := 1
163
164	# GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
165	# If '-Os' is enabled, disable it and print a warning.
166        ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
167          undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
168          $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE.  Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
169        endif
170
171    endif
172  endif
173endif
174
175ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
176	# This compiler flag is not supported by Clang:
177	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
178endif
179
180# Workaround for a gcc prelease that unfortunately was shipped in a suse release
181KBUILD_CFLAGS += -Wno-sign-compare
182#
183KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
184
185# Avoid indirect branches in kernel to deal with Spectre
186ifdef CONFIG_RETPOLINE
187  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
188  # Additionally, avoid generating expensive indirect jumps which
189  # are subject to retpolines for small number of switch cases.
190  # clang turns off jump table generation by default when under
191  # retpoline builds, however, gcc does not for x86. This has
192  # only been fixed starting from gcc stable version 8.4.0 and
193  # onwards, but not for older ones. See gcc bug #86952.
194  ifndef CONFIG_CC_IS_CLANG
195    KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
196  endif
197endif
198
199ifdef CONFIG_SLS
200  KBUILD_CFLAGS += -mharden-sls=all
201endif
202
203KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
204
205ifdef CONFIG_LTO_CLANG
206ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
207KBUILD_LDFLAGS	+= -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
208endif
209endif
210
211ifdef CONFIG_X86_NEED_RELOCS
212LDFLAGS_vmlinux := --emit-relocs --discard-none
213else
214LDFLAGS_vmlinux :=
215endif
216
217#
218# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
219# the linker to force 2MB page size regardless of the default page size used
220# by the linker.
221#
222ifdef CONFIG_X86_64
223LDFLAGS_vmlinux += -z max-page-size=0x200000
224endif
225
226
227archscripts: scripts_basic
228	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
229
230###
231# Syscall table generation
232
233archheaders:
234	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
235
236###
237# Kernel objects
238
239head-y := arch/x86/kernel/head_$(BITS).o
240head-y += arch/x86/kernel/head$(BITS).o
241head-y += arch/x86/kernel/ebda.o
242head-y += arch/x86/kernel/platform-quirks.o
243
244libs-y  += arch/x86/lib/
245
246# See arch/x86/Kbuild for content of core part of the kernel
247core-y += arch/x86/
248
249# drivers-y are linked after core-y
250drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
251drivers-$(CONFIG_PCI)            += arch/x86/pci/
252
253# must be linked after kernel/
254drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/
255
256# suspend and hibernation support
257drivers-$(CONFIG_PM) += arch/x86/power/
258
259drivers-$(CONFIG_FB) += arch/x86/video/
260
261####
262# boot loader support. Several targets are kept for legacy purposes
263
264boot := arch/x86/boot
265
266BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 isoimage
267
268PHONY += bzImage $(BOOT_TARGETS)
269
270# Don't compile Image in mixed build with "all" target
271ifndef KBUILD_MIXED_TREE
272# Default kernel to build
273all: bzImage
274endif
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 bzlilo
291install bzlilo:
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