xref: /openbmc/linux/arch/x86/Makefile (revision be2b81b5) 
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
24
25ifdef CONFIG_RETHUNK
26RETHUNK_CFLAGS		:= -mfunction-return=thunk-extern
27RETPOLINE_CFLAGS	+= $(RETHUNK_CFLAGS)
28endif
29
30export RETHUNK_CFLAGS
31export RETPOLINE_CFLAGS
32export RETPOLINE_VDSO_CFLAGS
33
34# For gcc stack alignment is specified with -mpreferred-stack-boundary,
35# clang has the option -mstack-alignment for that purpose.
36ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
37      cc_stack_align4 := -mpreferred-stack-boundary=2
38      cc_stack_align8 := -mpreferred-stack-boundary=3
39else ifneq ($(call cc-option, -mstack-alignment=16),)
40      cc_stack_align4 := -mstack-alignment=4
41      cc_stack_align8 := -mstack-alignment=8
42endif
43
44# How to compile the 16-bit code.  Note we always compile for -march=i386;
45# that way we can complain to the user if the CPU is insufficient.
46REALMODE_CFLAGS	:= -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \
47		   -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
48		   -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
49		   -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none)
50
51REALMODE_CFLAGS += -ffreestanding
52REALMODE_CFLAGS += -fno-stack-protector
53REALMODE_CFLAGS += -Wno-address-of-packed-member
54REALMODE_CFLAGS += $(cc_stack_align4)
55REALMODE_CFLAGS += $(CLANG_FLAGS)
56export REALMODE_CFLAGS
57
58# BITS is used as extension for files which are available in a 32 bit
59# and a 64 bit version to simplify shared Makefiles.
60# e.g.: obj-y += foo_$(BITS).o
61export BITS
62
63#
64# Prevent GCC from generating any FP code by mistake.
65#
66# This must happen before we try the -mpreferred-stack-boundary, see:
67#
68#    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
69#
70KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
71KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
72
73ifeq ($(CONFIG_X86_KERNEL_IBT),y)
74#
75# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate
76# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK
77# for jump-tables, as such, disable jump-tables for now.
78#
79# (jump-tables are implicitly disabled by RETPOLINE)
80#
81#   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816
82#
83KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables)
84else
85KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
86endif
87
88ifeq ($(CONFIG_X86_32),y)
89        BITS := 32
90        UTS_MACHINE := i386
91        CHECKFLAGS += -D__i386__
92
93        KBUILD_AFLAGS += -m32
94        KBUILD_CFLAGS += -m32
95
96        KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
97
98        # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
99        # with nonstandard options
100        KBUILD_CFLAGS += -fno-pic
101
102        # Align the stack to the register width instead of using the default
103        # alignment of 16 bytes. This reduces stack usage and the number of
104        # alignment instructions.
105        KBUILD_CFLAGS += $(cc_stack_align4)
106
107        # CPU-specific tuning. Anything which can be shared with UML should go here.
108        include $(srctree)/arch/x86/Makefile_32.cpu
109        KBUILD_CFLAGS += $(cflags-y)
110
111        # temporary until string.h is fixed
112        KBUILD_CFLAGS += -ffreestanding
113
114	ifeq ($(CONFIG_STACKPROTECTOR),y)
115		ifeq ($(CONFIG_SMP),y)
116			KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard
117		else
118			KBUILD_CFLAGS += -mstack-protector-guard=global
119		endif
120	endif
121else
122        BITS := 64
123        UTS_MACHINE := x86_64
124        CHECKFLAGS += -D__x86_64__
125
126        KBUILD_AFLAGS += -m64
127        KBUILD_CFLAGS += -m64
128
129        # Align jump targets to 1 byte, not the default 16 bytes:
130        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
131
132        # Pack loops tightly as well:
133        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
134
135        # Don't autogenerate traditional x87 instructions
136        KBUILD_CFLAGS += -mno-80387
137        KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
138
139        # By default gcc and clang use a stack alignment of 16 bytes for x86.
140        # However the standard kernel entry on x86-64 leaves the stack on an
141        # 8-byte boundary. If the compiler isn't informed about the actual
142        # alignment it will generate extra alignment instructions for the
143        # default alignment which keep the stack *mis*aligned.
144        # Furthermore an alignment to the register width reduces stack usage
145        # and the number of alignment instructions.
146        KBUILD_CFLAGS += $(cc_stack_align8)
147
148	# Use -mskip-rax-setup if supported.
149	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
150
151        # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
152        cflags-$(CONFIG_MK8)		+= -march=k8
153        cflags-$(CONFIG_MPSC)		+= -march=nocona
154        cflags-$(CONFIG_MCORE2)		+= -march=core2
155        cflags-$(CONFIG_MATOM)		+= -march=atom
156        cflags-$(CONFIG_GENERIC_CPU)	+= -mtune=generic
157        KBUILD_CFLAGS += $(cflags-y)
158
159        rustflags-$(CONFIG_MK8)		+= -Ctarget-cpu=k8
160        rustflags-$(CONFIG_MPSC)	+= -Ctarget-cpu=nocona
161        rustflags-$(CONFIG_MCORE2)	+= -Ctarget-cpu=core2
162        rustflags-$(CONFIG_MATOM)	+= -Ctarget-cpu=atom
163        rustflags-$(CONFIG_GENERIC_CPU)	+= -Ztune-cpu=generic
164        KBUILD_RUSTFLAGS += $(rustflags-y)
165
166        KBUILD_CFLAGS += -mno-red-zone
167        KBUILD_CFLAGS += -mcmodel=kernel
168        KBUILD_RUSTFLAGS += -Cno-redzone=y
169        KBUILD_RUSTFLAGS += -Ccode-model=kernel
170endif
171
172#
173# If the function graph tracer is used with mcount instead of fentry,
174# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
175# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
176#
177ifdef CONFIG_FUNCTION_GRAPH_TRACER
178  ifndef CONFIG_HAVE_FENTRY
179	ACCUMULATE_OUTGOING_ARGS := 1
180  endif
181endif
182
183ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
184	# This compiler flag is not supported by Clang:
185	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
186endif
187
188# Workaround for a gcc prelease that unfortunately was shipped in a suse release
189KBUILD_CFLAGS += -Wno-sign-compare
190#
191KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
192
193# Avoid indirect branches in kernel to deal with Spectre
194ifdef CONFIG_RETPOLINE
195  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
196  # Additionally, avoid generating expensive indirect jumps which
197  # are subject to retpolines for small number of switch cases.
198  # clang turns off jump table generation by default when under
199  # retpoline builds, however, gcc does not for x86. This has
200  # only been fixed starting from gcc stable version 8.4.0 and
201  # onwards, but not for older ones. See gcc bug #86952.
202  ifndef CONFIG_CC_IS_CLANG
203    KBUILD_CFLAGS += -fno-jump-tables
204  endif
205endif
206
207ifdef CONFIG_SLS
208  KBUILD_CFLAGS += -mharden-sls=all
209endif
210
211ifdef CONFIG_CALL_PADDING
212PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
213KBUILD_CFLAGS += $(PADDING_CFLAGS)
214export PADDING_CFLAGS
215endif
216
217KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
218
219ifdef CONFIG_LTO_CLANG
220ifeq ($(call test-lt, $(CONFIG_LLD_VERSION), 130000),y)
221KBUILD_LDFLAGS	+= -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
222endif
223endif
224
225ifdef CONFIG_X86_NEED_RELOCS
226LDFLAGS_vmlinux := --emit-relocs --discard-none
227else
228LDFLAGS_vmlinux :=
229endif
230
231#
232# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
233# the linker to force 2MB page size regardless of the default page size used
234# by the linker.
235#
236ifdef CONFIG_X86_64
237LDFLAGS_vmlinux += -z max-page-size=0x200000
238endif
239
240
241archscripts: scripts_basic
242	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
243
244###
245# Syscall table generation
246
247archheaders:
248	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
249
250###
251# Kernel objects
252
253libs-y  += arch/x86/lib/
254
255# drivers-y are linked after core-y
256drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
257drivers-$(CONFIG_PCI)            += arch/x86/pci/
258
259# suspend and hibernation support
260drivers-$(CONFIG_PM) += arch/x86/power/
261
262drivers-$(CONFIG_FB) += arch/x86/video/
263
264####
265# boot loader support. Several targets are kept for legacy purposes
266
267boot := arch/x86/boot
268
269BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
270
271PHONY += bzImage $(BOOT_TARGETS)
272
273# Default kernel to build
274all: bzImage
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
291install:
292	$(call cmd,install)
293
294PHONY += vdso_install
295vdso_install:
296	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
297
298archprepare: checkbin
299checkbin:
300ifdef CONFIG_RETPOLINE
301ifeq ($(RETPOLINE_CFLAGS),)
302	@echo "You are building kernel with non-retpoline compiler." >&2
303	@echo "Please update your compiler." >&2
304	@false
305endif
306endif
307
308archclean:
309	$(Q)rm -rf $(objtree)/arch/i386
310	$(Q)rm -rf $(objtree)/arch/x86_64
311
312define archhelp
313  echo  '* bzImage		- Compressed kernel image (arch/x86/boot/bzImage)'
314  echo  '  install		- Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
315  echo  '			  (distribution) /sbin/$(INSTALLKERNEL) or install to '
316  echo  '			  $$(INSTALL_PATH) and run lilo'
317  echo  ''
318  echo  '  fdimage		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
319  echo  '  fdimage144		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
320  echo  '  fdimage288		- Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
321  echo  '  hdimage		- Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
322  echo  '  isoimage		- Create a boot CD-ROM image (arch/x86/boot/image.iso)'
323  echo  '			  bzdisk/fdimage*/hdimage/isoimage also accept:'
324  echo  '			  FDARGS="..."  arguments for the booted kernel'
325  echo  '			  FDINITRD=file initrd for the booted kernel'
326  echo  ''
327  echo  '  kvm_guest.config	- Enable Kconfig items for running this kernel as a KVM guest'
328  echo  '  xen.config		- Enable Kconfig items for running this kernel as a Xen guest'
329  echo  '  x86_debug.config	- Enable tip tree debugging options for testing'
330
331endef
332