xref: /openbmc/linux/arch/x86/Makefile (revision 2a9eb57e) 
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
71
72ifeq ($(CONFIG_X86_KERNEL_IBT),y)
73#
74# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate
75# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK
76# for jump-tables, as such, disable jump-tables for now.
77#
78# (jump-tables are implicitly disabled by RETPOLINE)
79#
80#   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816
81#
82KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables)
83else
84KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
85endif
86
87ifeq ($(CONFIG_X86_32),y)
88        BITS := 32
89        UTS_MACHINE := i386
90        CHECKFLAGS += -D__i386__
91
92        KBUILD_AFLAGS += -m32
93        KBUILD_CFLAGS += -m32
94
95        KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
96
97        # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
98        # with nonstandard options
99        KBUILD_CFLAGS += -fno-pic
100
101        # Align the stack to the register width instead of using the default
102        # alignment of 16 bytes. This reduces stack usage and the number of
103        # alignment instructions.
104        KBUILD_CFLAGS += $(cc_stack_align4)
105
106        # CPU-specific tuning. Anything which can be shared with UML should go here.
107        include $(srctree)/arch/x86/Makefile_32.cpu
108        KBUILD_CFLAGS += $(cflags-y)
109
110        # temporary until string.h is fixed
111        KBUILD_CFLAGS += -ffreestanding
112
113	ifeq ($(CONFIG_STACKPROTECTOR),y)
114		ifeq ($(CONFIG_SMP),y)
115			KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard
116		else
117			KBUILD_CFLAGS += -mstack-protector-guard=global
118		endif
119	endif
120else
121        BITS := 64
122        UTS_MACHINE := x86_64
123        CHECKFLAGS += -D__x86_64__
124
125        KBUILD_AFLAGS += -m64
126        KBUILD_CFLAGS += -m64
127
128        # Align jump targets to 1 byte, not the default 16 bytes:
129        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
130
131        # Pack loops tightly as well:
132        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
133
134        # Don't autogenerate traditional x87 instructions
135        KBUILD_CFLAGS += -mno-80387
136        KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
137
138        # By default gcc and clang use a stack alignment of 16 bytes for x86.
139        # However the standard kernel entry on x86-64 leaves the stack on an
140        # 8-byte boundary. If the compiler isn't informed about the actual
141        # alignment it will generate extra alignment instructions for the
142        # default alignment which keep the stack *mis*aligned.
143        # Furthermore an alignment to the register width reduces stack usage
144        # and the number of alignment instructions.
145        KBUILD_CFLAGS += $(cc_stack_align8)
146
147	# Use -mskip-rax-setup if supported.
148	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
149
150        # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
151        cflags-$(CONFIG_MK8)		+= -march=k8
152        cflags-$(CONFIG_MPSC)		+= -march=nocona
153        cflags-$(CONFIG_MCORE2)		+= -march=core2
154        cflags-$(CONFIG_MATOM)		+= -march=atom
155        cflags-$(CONFIG_GENERIC_CPU)	+= -mtune=generic
156        KBUILD_CFLAGS += $(cflags-y)
157
158        KBUILD_CFLAGS += -mno-red-zone
159        KBUILD_CFLAGS += -mcmodel=kernel
160endif
161
162#
163# If the function graph tracer is used with mcount instead of fentry,
164# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
165# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
166#
167ifdef CONFIG_FUNCTION_GRAPH_TRACER
168  ifndef CONFIG_HAVE_FENTRY
169	ACCUMULATE_OUTGOING_ARGS := 1
170  endif
171endif
172
173ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
174	# This compiler flag is not supported by Clang:
175	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
176endif
177
178# Workaround for a gcc prelease that unfortunately was shipped in a suse release
179KBUILD_CFLAGS += -Wno-sign-compare
180#
181KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
182
183# Avoid indirect branches in kernel to deal with Spectre
184ifdef CONFIG_RETPOLINE
185  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
186  # Additionally, avoid generating expensive indirect jumps which
187  # are subject to retpolines for small number of switch cases.
188  # clang turns off jump table generation by default when under
189  # retpoline builds, however, gcc does not for x86. This has
190  # only been fixed starting from gcc stable version 8.4.0 and
191  # onwards, but not for older ones. See gcc bug #86952.
192  ifndef CONFIG_CC_IS_CLANG
193    KBUILD_CFLAGS += -fno-jump-tables
194  endif
195endif
196
197ifdef CONFIG_SLS
198  KBUILD_CFLAGS += -mharden-sls=all
199endif
200
201KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
202
203ifdef CONFIG_LTO_CLANG
204ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
205KBUILD_LDFLAGS	+= -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
206endif
207endif
208
209ifdef CONFIG_X86_NEED_RELOCS
210LDFLAGS_vmlinux := --emit-relocs --discard-none
211else
212LDFLAGS_vmlinux :=
213endif
214
215#
216# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
217# the linker to force 2MB page size regardless of the default page size used
218# by the linker.
219#
220ifdef CONFIG_X86_64
221LDFLAGS_vmlinux += -z max-page-size=0x200000
222endif
223
224
225archscripts: scripts_basic
226	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
227
228###
229# Syscall table generation
230
231archheaders:
232	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
233
234###
235# Kernel objects
236
237head-y := arch/x86/kernel/head_$(BITS).o
238head-y += arch/x86/kernel/head$(BITS).o
239head-y += arch/x86/kernel/ebda.o
240head-y += arch/x86/kernel/platform-quirks.o
241
242libs-y  += arch/x86/lib/
243
244# drivers-y are linked after core-y
245drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
246drivers-$(CONFIG_PCI)            += arch/x86/pci/
247
248# suspend and hibernation support
249drivers-$(CONFIG_PM) += arch/x86/power/
250
251drivers-$(CONFIG_FB) += arch/x86/video/
252
253####
254# boot loader support. Several targets are kept for legacy purposes
255
256boot := arch/x86/boot
257
258BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
259
260PHONY += bzImage $(BOOT_TARGETS)
261
262# Default kernel to build
263all: bzImage
264
265# KBUILD_IMAGE specify target image being built
266KBUILD_IMAGE := $(boot)/bzImage
267
268bzImage: vmlinux
269ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
270	$(Q)$(MAKE) $(build)=arch/x86/tools posttest
271endif
272	$(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
273	$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
274	$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
275
276$(BOOT_TARGETS): vmlinux
277	$(Q)$(MAKE) $(build)=$(boot) $@
278
279PHONY += install
280install:
281	$(call cmd,install)
282
283PHONY += vdso_install
284vdso_install:
285	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
286
287archprepare: checkbin
288checkbin:
289ifndef CONFIG_CC_HAS_ASM_GOTO
290	@echo Compiler lacks asm-goto support.
291	@exit 1
292endif
293ifdef CONFIG_RETPOLINE
294ifeq ($(RETPOLINE_CFLAGS),)
295	@echo "You are building kernel with non-retpoline compiler." >&2
296	@echo "Please update your compiler." >&2
297	@false
298endif
299endif
300
301archclean:
302	$(Q)rm -rf $(objtree)/arch/i386
303	$(Q)rm -rf $(objtree)/arch/x86_64
304
305define archhelp
306  echo  '* bzImage		- Compressed kernel image (arch/x86/boot/bzImage)'
307  echo  '  install		- Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
308  echo  '			  (distribution) /sbin/$(INSTALLKERNEL) or install to '
309  echo  '			  $$(INSTALL_PATH) and run lilo'
310  echo  ''
311  echo  '  fdimage		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
312  echo  '  fdimage144		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
313  echo  '  fdimage288		- Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
314  echo  '  hdimage		- Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
315  echo  '  isoimage		- Create a boot CD-ROM image (arch/x86/boot/image.iso)'
316  echo  '			  bzdisk/fdimage*/hdimage/isoimage also accept:'
317  echo  '			  FDARGS="..."  arguments for the booted kernel'
318  echo  '			  FDINITRD=file initrd for the booted kernel'
319  echo  ''
320  echo  '  kvm_guest.config	- Enable Kconfig items for running this kernel as a KVM guest'
321  echo  '  xen.config		- Enable Kconfig items for running this kernel as a Xen guest'
322  echo  '  x86_debug.config	- Enable tip tree debugging options for testing'
323
324endef
325