xref: /openbmc/linux/arch/x86/Makefile (revision add48ba4) 
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 \
35		   -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
36		   -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
37		   -mno-mmx -mno-sse
38
39REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -ffreestanding)
40REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_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), $(cc_stack_align4))
43export REALMODE_CFLAGS
44
45# BITS is used as extension for files which are available in a 32 bit
46# and a 64 bit version to simplify shared Makefiles.
47# e.g.: obj-y += foo_$(BITS).o
48export BITS
49
50ifdef CONFIG_X86_NEED_RELOCS
51        LDFLAGS_vmlinux := --emit-relocs --discard-none
52endif
53
54#
55# Prevent GCC from generating any FP code by mistake.
56#
57# This must happen before we try the -mpreferred-stack-boundary, see:
58#
59#    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
60#
61KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
62KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
63
64ifeq ($(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
180KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
181
182#
183# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
184# the linker to force 2MB page size regardless of the default page size used
185# by the linker.
186#
187ifdef CONFIG_X86_64
188KBUILD_LDFLAGS += $(call ld-option, -z max-page-size=0x200000)
189endif
190
191# Workaround for a gcc prelease that unfortunately was shipped in a suse release
192KBUILD_CFLAGS += -Wno-sign-compare
193#
194KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
195
196# Avoid indirect branches in kernel to deal with Spectre
197ifdef CONFIG_RETPOLINE
198  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
199  # Additionally, avoid generating expensive indirect jumps which
200  # are subject to retpolines for small number of switch cases.
201  # clang turns off jump table generation by default when under
202  # retpoline builds, however, gcc does not for x86. This has
203  # only been fixed starting from gcc stable version 8.4.0 and
204  # onwards, but not for older ones. See gcc bug #86952.
205  ifndef CONFIG_CC_IS_CLANG
206    KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
207  endif
208endif
209
210archscripts: scripts_basic
211	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
212
213###
214# Syscall table generation
215
216archheaders:
217	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
218
219###
220# Kernel objects
221
222head-y := arch/x86/kernel/head_$(BITS).o
223head-y += arch/x86/kernel/head$(BITS).o
224head-y += arch/x86/kernel/ebda.o
225head-y += arch/x86/kernel/platform-quirks.o
226
227libs-y  += arch/x86/lib/
228
229# See arch/x86/Kbuild for content of core part of the kernel
230core-y += arch/x86/
231
232# drivers-y are linked after core-y
233drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
234drivers-$(CONFIG_PCI)            += arch/x86/pci/
235
236# must be linked after kernel/
237drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/
238
239# suspend and hibernation support
240drivers-$(CONFIG_PM) += arch/x86/power/
241
242drivers-$(CONFIG_FB) += arch/x86/video/
243
244####
245# boot loader support. Several targets are kept for legacy purposes
246
247boot := arch/x86/boot
248
249BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 isoimage
250
251PHONY += bzImage $(BOOT_TARGETS)
252
253# Default kernel to build
254all: bzImage
255
256# KBUILD_IMAGE specify target image being built
257KBUILD_IMAGE := $(boot)/bzImage
258
259bzImage: vmlinux
260ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
261	$(Q)$(MAKE) $(build)=arch/x86/tools posttest
262endif
263	$(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
264	$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
265	$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
266
267$(BOOT_TARGETS): vmlinux
268	$(Q)$(MAKE) $(build)=$(boot) $@
269
270PHONY += install bzlilo
271install bzlilo:
272	$(Q)$(MAKE) $(build)=$(boot) $@
273
274PHONY += vdso_install
275vdso_install:
276	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
277
278archprepare: checkbin
279checkbin:
280ifndef CONFIG_CC_HAS_ASM_GOTO
281	@echo Compiler lacks asm-goto support.
282	@exit 1
283endif
284ifdef CONFIG_RETPOLINE
285ifeq ($(RETPOLINE_CFLAGS),)
286	@echo "You are building kernel with non-retpoline compiler." >&2
287	@echo "Please update your compiler." >&2
288	@false
289endif
290endif
291
292archclean:
293	$(Q)rm -rf $(objtree)/arch/i386
294	$(Q)rm -rf $(objtree)/arch/x86_64
295	$(Q)$(MAKE) $(clean)=$(boot)
296	$(Q)$(MAKE) $(clean)=arch/x86/tools
297
298define archhelp
299  echo  '* bzImage      - Compressed kernel image (arch/x86/boot/bzImage)'
300  echo  '  install      - Install kernel using'
301  echo  '                  (your) ~/bin/$(INSTALLKERNEL) or'
302  echo  '                  (distribution) /sbin/$(INSTALLKERNEL) or'
303  echo  '                  install to $$(INSTALL_PATH) and run lilo'
304  echo  '  fdimage      - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
305  echo  '  fdimage144   - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
306  echo  '  fdimage288   - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
307  echo  '  isoimage     - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
308  echo  '                  bzdisk/fdimage*/isoimage also accept:'
309  echo  '                  FDARGS="..."  arguments for the booted kernel'
310  echo  '                  FDINITRD=file initrd for the booted kernel'
311endef
312