xref: /openbmc/linux/arch/x86/Makefile (revision f97769fd) 
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 += -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), $(cc_stack_align4))
43export REALMODE_CFLAGS
44
45# BITS is used as extension for files which are available in a 32 bit
46# and a 64 bit version to simplify shared Makefiles.
47# e.g.: obj-y += foo_$(BITS).o
48export BITS
49
50#
51# Prevent GCC from generating any FP code by mistake.
52#
53# This must happen before we try the -mpreferred-stack-boundary, see:
54#
55#    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
56#
57KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
58KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
59
60ifeq ($(CONFIG_X86_32),y)
61        BITS := 32
62        UTS_MACHINE := i386
63        CHECKFLAGS += -D__i386__
64
65        biarch := $(call cc-option,-m32)
66        KBUILD_AFLAGS += $(biarch)
67        KBUILD_CFLAGS += $(biarch)
68
69        KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
70
71        # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
72        # with nonstandard options
73        KBUILD_CFLAGS += -fno-pic
74
75        # Align the stack to the register width instead of using the default
76        # alignment of 16 bytes. This reduces stack usage and the number of
77        # alignment instructions.
78        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
79
80        # CPU-specific tuning. Anything which can be shared with UML should go here.
81        include arch/x86/Makefile_32.cpu
82        KBUILD_CFLAGS += $(cflags-y)
83
84        # temporary until string.h is fixed
85        KBUILD_CFLAGS += -ffreestanding
86else
87        BITS := 64
88        UTS_MACHINE := x86_64
89        CHECKFLAGS += -D__x86_64__
90
91        biarch := -m64
92        KBUILD_AFLAGS += -m64
93        KBUILD_CFLAGS += -m64
94
95        # Align jump targets to 1 byte, not the default 16 bytes:
96        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
97
98        # Pack loops tightly as well:
99        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
100
101        # Don't autogenerate traditional x87 instructions
102        KBUILD_CFLAGS += $(call cc-option,-mno-80387)
103        KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
104
105        # By default gcc and clang use a stack alignment of 16 bytes for x86.
106        # However the standard kernel entry on x86-64 leaves the stack on an
107        # 8-byte boundary. If the compiler isn't informed about the actual
108        # alignment it will generate extra alignment instructions for the
109        # default alignment which keep the stack *mis*aligned.
110        # Furthermore an alignment to the register width reduces stack usage
111        # and the number of alignment instructions.
112        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
113
114	# Use -mskip-rax-setup if supported.
115	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
116
117        # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
118        cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
119        cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
120
121        cflags-$(CONFIG_MCORE2) += \
122                $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
123	cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
124		$(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
125        cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
126        KBUILD_CFLAGS += $(cflags-y)
127
128        KBUILD_CFLAGS += -mno-red-zone
129        KBUILD_CFLAGS += -mcmodel=kernel
130endif
131
132ifdef CONFIG_X86_X32
133	x32_ld_ok := $(call try-run,\
134			/bin/echo -e '1: .quad 1b' | \
135			$(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
136			$(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMPO" && \
137			$(LD) -m elf32_x86_64 "$$TMPO" -o "$$TMP",y,n)
138        ifeq ($(x32_ld_ok),y)
139                CONFIG_X86_X32_ABI := y
140                KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
141                KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
142        else
143                $(warning CONFIG_X86_X32 enabled but no binutils support)
144        endif
145endif
146export CONFIG_X86_X32_ABI
147
148#
149# If the function graph tracer is used with mcount instead of fentry,
150# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
151# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
152#
153ifdef CONFIG_FUNCTION_GRAPH_TRACER
154  ifndef CONFIG_HAVE_FENTRY
155	ACCUMULATE_OUTGOING_ARGS := 1
156  else
157    ifeq ($(call cc-option-yn, -mfentry), n)
158	ACCUMULATE_OUTGOING_ARGS := 1
159
160	# GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
161	# If '-Os' is enabled, disable it and print a warning.
162        ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
163          undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
164          $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE.  Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
165        endif
166
167    endif
168  endif
169endif
170
171ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
172	# This compiler flag is not supported by Clang:
173	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
174endif
175
176# Workaround for a gcc prelease that unfortunately was shipped in a suse release
177KBUILD_CFLAGS += -Wno-sign-compare
178#
179KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
180
181# Avoid indirect branches in kernel to deal with Spectre
182ifdef CONFIG_RETPOLINE
183  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
184  # Additionally, avoid generating expensive indirect jumps which
185  # are subject to retpolines for small number of switch cases.
186  # clang turns off jump table generation by default when under
187  # retpoline builds, however, gcc does not for x86. This has
188  # only been fixed starting from gcc stable version 8.4.0 and
189  # onwards, but not for older ones. See gcc bug #86952.
190  ifndef CONFIG_CC_IS_CLANG
191    KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
192  endif
193endif
194
195KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
196
197ifdef CONFIG_X86_NEED_RELOCS
198LDFLAGS_vmlinux := --emit-relocs --discard-none
199else
200LDFLAGS_vmlinux :=
201endif
202
203#
204# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
205# the linker to force 2MB page size regardless of the default page size used
206# by the linker.
207#
208ifdef CONFIG_X86_64
209LDFLAGS_vmlinux += -z max-page-size=0x200000
210endif
211
212archscripts: scripts_basic
213	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
214
215###
216# Syscall table generation
217
218archheaders:
219	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
220
221###
222# Kernel objects
223
224head-y := arch/x86/kernel/head_$(BITS).o
225head-y += arch/x86/kernel/head$(BITS).o
226head-y += arch/x86/kernel/ebda.o
227head-y += arch/x86/kernel/platform-quirks.o
228
229libs-y  += arch/x86/lib/
230
231# See arch/x86/Kbuild for content of core part of the kernel
232core-y += arch/x86/
233
234# drivers-y are linked after core-y
235drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
236drivers-$(CONFIG_PCI)            += arch/x86/pci/
237
238# must be linked after kernel/
239drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/
240
241# suspend and hibernation support
242drivers-$(CONFIG_PM) += arch/x86/power/
243
244drivers-$(CONFIG_FB) += arch/x86/video/
245
246####
247# boot loader support. Several targets are kept for legacy purposes
248
249boot := arch/x86/boot
250
251BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 isoimage
252
253PHONY += bzImage $(BOOT_TARGETS)
254
255# Default kernel to build
256all: bzImage
257
258# KBUILD_IMAGE specify target image being built
259KBUILD_IMAGE := $(boot)/bzImage
260
261bzImage: vmlinux
262ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
263	$(Q)$(MAKE) $(build)=arch/x86/tools posttest
264endif
265	$(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
266	$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
267	$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
268
269$(BOOT_TARGETS): vmlinux
270	$(Q)$(MAKE) $(build)=$(boot) $@
271
272PHONY += install bzlilo
273install bzlilo:
274	$(Q)$(MAKE) $(build)=$(boot) $@
275
276PHONY += vdso_install
277vdso_install:
278	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
279
280archprepare: checkbin
281checkbin:
282ifndef CONFIG_CC_HAS_ASM_GOTO
283	@echo Compiler lacks asm-goto support.
284	@exit 1
285endif
286ifdef CONFIG_RETPOLINE
287ifeq ($(RETPOLINE_CFLAGS),)
288	@echo "You are building kernel with non-retpoline compiler." >&2
289	@echo "Please update your compiler." >&2
290	@false
291endif
292endif
293
294archclean:
295	$(Q)rm -rf $(objtree)/arch/i386
296	$(Q)rm -rf $(objtree)/arch/x86_64
297	$(Q)$(MAKE) $(clean)=$(boot)
298	$(Q)$(MAKE) $(clean)=arch/x86/tools
299
300define archhelp
301  echo  '* bzImage      - Compressed kernel image (arch/x86/boot/bzImage)'
302  echo  '  install      - Install kernel using'
303  echo  '                  (your) ~/bin/$(INSTALLKERNEL) or'
304  echo  '                  (distribution) /sbin/$(INSTALLKERNEL) or'
305  echo  '                  install to $$(INSTALL_PATH) and run lilo'
306  echo  '  fdimage      - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
307  echo  '  fdimage144   - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
308  echo  '  fdimage288   - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
309  echo  '  isoimage     - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
310  echo  '                  bzdisk/fdimage*/isoimage also accept:'
311  echo  '                  FDARGS="..."  arguments for the booted kernel'
312  echo  '                  FDINITRD=file initrd for the booted kernel'
313endef
314