xref: /openbmc/linux/arch/x86/Makefile (revision 0a4cad9c) 
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
15ifdef CONFIG_CC_IS_GCC
16RETPOLINE_CFLAGS	:= $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
17RETPOLINE_CFLAGS	+= $(call cc-option,-mindirect-branch-cs-prefix)
18RETPOLINE_VDSO_CFLAGS	:= $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register)
19endif
20ifdef CONFIG_CC_IS_CLANG
21RETPOLINE_CFLAGS	:= -mretpoline-external-thunk
22RETPOLINE_VDSO_CFLAGS	:= -mretpoline
23endif
24export RETPOLINE_CFLAGS
25export RETPOLINE_VDSO_CFLAGS
26
27# For gcc stack alignment is specified with -mpreferred-stack-boundary,
28# clang has the option -mstack-alignment for that purpose.
29ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
30      cc_stack_align4 := -mpreferred-stack-boundary=2
31      cc_stack_align8 := -mpreferred-stack-boundary=3
32else ifneq ($(call cc-option, -mstack-alignment=16),)
33      cc_stack_align4 := -mstack-alignment=4
34      cc_stack_align8 := -mstack-alignment=8
35endif
36
37# How to compile the 16-bit code.  Note we always compile for -march=i386;
38# that way we can complain to the user if the CPU is insufficient.
39REALMODE_CFLAGS	:= -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \
40		   -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
41		   -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
42		   -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none)
43
44REALMODE_CFLAGS += -ffreestanding
45REALMODE_CFLAGS += -fno-stack-protector
46REALMODE_CFLAGS += -Wno-address-of-packed-member
47REALMODE_CFLAGS += $(cc_stack_align4)
48REALMODE_CFLAGS += $(CLANG_FLAGS)
49export REALMODE_CFLAGS
50
51# BITS is used as extension for files which are available in a 32 bit
52# and a 64 bit version to simplify shared Makefiles.
53# e.g.: obj-y += foo_$(BITS).o
54export BITS
55
56#
57# Prevent GCC from generating any FP code by mistake.
58#
59# This must happen before we try the -mpreferred-stack-boundary, see:
60#
61#    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
62#
63KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
64
65ifeq ($(CONFIG_X86_KERNEL_IBT),y)
66#
67# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate
68# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK
69# for jump-tables, as such, disable jump-tables for now.
70#
71# (jump-tables are implicitly disabled by RETPOLINE)
72#
73#   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816
74#
75KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables)
76else
77KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
78endif
79
80ifeq ($(CONFIG_X86_32),y)
81        BITS := 32
82        UTS_MACHINE := i386
83        CHECKFLAGS += -D__i386__
84
85        KBUILD_AFLAGS += -m32
86        KBUILD_CFLAGS += -m32
87
88        KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
89
90        # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
91        # with nonstandard options
92        KBUILD_CFLAGS += -fno-pic
93
94        # Align the stack to the register width instead of using the default
95        # alignment of 16 bytes. This reduces stack usage and the number of
96        # alignment instructions.
97        KBUILD_CFLAGS += $(cc_stack_align4)
98
99        # CPU-specific tuning. Anything which can be shared with UML should go here.
100        include $(srctree)/arch/x86/Makefile_32.cpu
101        KBUILD_CFLAGS += $(cflags-y)
102
103        # temporary until string.h is fixed
104        KBUILD_CFLAGS += -ffreestanding
105
106	ifeq ($(CONFIG_STACKPROTECTOR),y)
107		ifeq ($(CONFIG_SMP),y)
108			KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard
109		else
110			KBUILD_CFLAGS += -mstack-protector-guard=global
111		endif
112	endif
113else
114        BITS := 64
115        UTS_MACHINE := x86_64
116        CHECKFLAGS += -D__x86_64__
117
118        KBUILD_AFLAGS += -m64
119        KBUILD_CFLAGS += -m64
120
121        # Align jump targets to 1 byte, not the default 16 bytes:
122        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
123
124        # Pack loops tightly as well:
125        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
126
127        # Don't autogenerate traditional x87 instructions
128        KBUILD_CFLAGS += -mno-80387
129        KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
130
131        # By default gcc and clang use a stack alignment of 16 bytes for x86.
132        # However the standard kernel entry on x86-64 leaves the stack on an
133        # 8-byte boundary. If the compiler isn't informed about the actual
134        # alignment it will generate extra alignment instructions for the
135        # default alignment which keep the stack *mis*aligned.
136        # Furthermore an alignment to the register width reduces stack usage
137        # and the number of alignment instructions.
138        KBUILD_CFLAGS += $(cc_stack_align8)
139
140	# Use -mskip-rax-setup if supported.
141	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
142
143        # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
144        cflags-$(CONFIG_MK8)		+= -march=k8
145        cflags-$(CONFIG_MPSC)		+= -march=nocona
146        cflags-$(CONFIG_MCORE2)		+= -march=core2
147        cflags-$(CONFIG_MATOM)		+= -march=atom
148        cflags-$(CONFIG_GENERIC_CPU)	+= -mtune=generic
149        KBUILD_CFLAGS += $(cflags-y)
150
151        KBUILD_CFLAGS += -mno-red-zone
152        KBUILD_CFLAGS += -mcmodel=kernel
153endif
154
155#
156# If the function graph tracer is used with mcount instead of fentry,
157# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
158# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
159#
160ifdef CONFIG_FUNCTION_GRAPH_TRACER
161  ifndef CONFIG_HAVE_FENTRY
162	ACCUMULATE_OUTGOING_ARGS := 1
163  endif
164endif
165
166ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
167	# This compiler flag is not supported by Clang:
168	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
169endif
170
171# Workaround for a gcc prelease that unfortunately was shipped in a suse release
172KBUILD_CFLAGS += -Wno-sign-compare
173#
174KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
175
176# Avoid indirect branches in kernel to deal with Spectre
177ifdef CONFIG_RETPOLINE
178  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
179  # Additionally, avoid generating expensive indirect jumps which
180  # are subject to retpolines for small number of switch cases.
181  # clang turns off jump table generation by default when under
182  # retpoline builds, however, gcc does not for x86. This has
183  # only been fixed starting from gcc stable version 8.4.0 and
184  # onwards, but not for older ones. See gcc bug #86952.
185  ifndef CONFIG_CC_IS_CLANG
186    KBUILD_CFLAGS += -fno-jump-tables
187  endif
188endif
189
190ifdef CONFIG_SLS
191  KBUILD_CFLAGS += -mharden-sls=all
192endif
193
194KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
195
196ifdef CONFIG_LTO_CLANG
197ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
198KBUILD_LDFLAGS	+= -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
199endif
200endif
201
202ifdef CONFIG_X86_NEED_RELOCS
203LDFLAGS_vmlinux := --emit-relocs --discard-none
204else
205LDFLAGS_vmlinux :=
206endif
207
208#
209# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
210# the linker to force 2MB page size regardless of the default page size used
211# by the linker.
212#
213ifdef CONFIG_X86_64
214LDFLAGS_vmlinux += -z max-page-size=0x200000
215endif
216
217
218archscripts: scripts_basic
219	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
220
221###
222# Syscall table generation
223
224archheaders:
225	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
226
227###
228# Kernel objects
229
230head-y := arch/x86/kernel/head_$(BITS).o
231head-y += arch/x86/kernel/head$(BITS).o
232head-y += arch/x86/kernel/ebda.o
233head-y += arch/x86/kernel/platform-quirks.o
234
235libs-y  += arch/x86/lib/
236
237# drivers-y are linked after core-y
238drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
239drivers-$(CONFIG_PCI)            += arch/x86/pci/
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 hdimage 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
273install:
274	$(CONFIG_SHELL) $(srctree)/$(boot)/install.sh $(KERNELRELEASE) \
275		$(KBUILD_IMAGE) System.map "$(INSTALL_PATH)"
276
277PHONY += vdso_install
278vdso_install:
279	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
280
281archprepare: checkbin
282checkbin:
283ifndef CONFIG_CC_HAS_ASM_GOTO
284	@echo Compiler lacks asm-goto support.
285	@exit 1
286endif
287ifdef CONFIG_RETPOLINE
288ifeq ($(RETPOLINE_CFLAGS),)
289	@echo "You are building kernel with non-retpoline compiler." >&2
290	@echo "Please update your compiler." >&2
291	@false
292endif
293endif
294
295archclean:
296	$(Q)rm -rf $(objtree)/arch/i386
297	$(Q)rm -rf $(objtree)/arch/x86_64
298
299define archhelp
300  echo  '* bzImage		- Compressed kernel image (arch/x86/boot/bzImage)'
301  echo  '  install		- Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
302  echo  '			  (distribution) /sbin/$(INSTALLKERNEL) or install to '
303  echo  '			  $$(INSTALL_PATH) and run lilo'
304  echo  ''
305  echo  '  fdimage		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
306  echo  '  fdimage144		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
307  echo  '  fdimage288		- Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
308  echo  '  hdimage		- Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
309  echo  '  isoimage		- Create a boot CD-ROM image (arch/x86/boot/image.iso)'
310  echo  '			  bzdisk/fdimage*/hdimage/isoimage also accept:'
311  echo  '			  FDARGS="..."  arguments for the booted kernel'
312  echo  '			  FDINITRD=file initrd for the booted kernel'
313  echo  ''
314  echo  '  kvm_guest.config	- Enable Kconfig items for running this kernel as a KVM guest'
315  echo  '  xen.config		- Enable Kconfig items for running this kernel as a Xen guest'
316
317endef
318