xref: /openbmc/linux/arch/x86/Makefile (revision 7d94ab16) 
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
180# Stackpointer is addressed different for 32 bit and 64 bit x86
181sp-$(CONFIG_X86_32) := esp
182sp-$(CONFIG_X86_64) := rsp
183
184# do binutils support CFI?
185cfi := $(call as-instr,.cfi_startproc\n.cfi_rel_offset $(sp-y)$(comma)0\n.cfi_endproc,-DCONFIG_AS_CFI=1)
186# is .cfi_signal_frame supported too?
187cfi-sigframe := $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1)
188cfi-sections := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTIONS=1)
189
190# does binutils support specific instructions?
191asinstr += $(call as-instr,pshufb %xmm0$(comma)%xmm0,-DCONFIG_AS_SSSE3=1)
192avx_instr := $(call as-instr,vxorps %ymm0$(comma)%ymm1$(comma)%ymm2,-DCONFIG_AS_AVX=1)
193avx2_instr :=$(call as-instr,vpbroadcastb %xmm0$(comma)%ymm1,-DCONFIG_AS_AVX2=1)
194avx512_instr :=$(call as-instr,vpmovm2b %k1$(comma)%zmm5,-DCONFIG_AS_AVX512=1)
195sha1_ni_instr :=$(call as-instr,sha1msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA1_NI=1)
196sha256_ni_instr :=$(call as-instr,sha256msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA256_NI=1)
197
198KBUILD_AFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr)
199KBUILD_CFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr)
200
201KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
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
209KBUILD_LDFLAGS += $(call ld-option, -z max-page-size=0x200000)
210endif
211
212# Workaround for a gcc prelease that unfortunately was shipped in a suse release
213KBUILD_CFLAGS += -Wno-sign-compare
214#
215KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
216
217# Avoid indirect branches in kernel to deal with Spectre
218ifdef CONFIG_RETPOLINE
219  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
220  # Additionally, avoid generating expensive indirect jumps which
221  # are subject to retpolines for small number of switch cases.
222  # clang turns off jump table generation by default when under
223  # retpoline builds, however, gcc does not for x86. This has
224  # only been fixed starting from gcc stable version 8.4.0 and
225  # onwards, but not for older ones. See gcc bug #86952.
226  ifndef CONFIG_CC_IS_CLANG
227    KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
228  endif
229endif
230
231archscripts: scripts_basic
232	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
233
234###
235# Syscall table generation
236
237archheaders:
238	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
239
240###
241# Kernel objects
242
243head-y := arch/x86/kernel/head_$(BITS).o
244head-y += arch/x86/kernel/head$(BITS).o
245head-y += arch/x86/kernel/ebda.o
246head-y += arch/x86/kernel/platform-quirks.o
247
248libs-y  += arch/x86/lib/
249
250# See arch/x86/Kbuild for content of core part of the kernel
251core-y += arch/x86/
252
253# drivers-y are linked after core-y
254drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
255drivers-$(CONFIG_PCI)            += arch/x86/pci/
256
257# must be linked after kernel/
258drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/
259
260# suspend and hibernation support
261drivers-$(CONFIG_PM) += arch/x86/power/
262
263drivers-$(CONFIG_FB) += arch/x86/video/
264
265####
266# boot loader support. Several targets are kept for legacy purposes
267
268boot := arch/x86/boot
269
270BOOT_TARGETS = bzlilo bzdisk fdimage fdimage144 fdimage288 isoimage
271
272PHONY += bzImage $(BOOT_TARGETS)
273
274# Default kernel to build
275all: bzImage
276
277# KBUILD_IMAGE specify target image being built
278KBUILD_IMAGE := $(boot)/bzImage
279
280bzImage: vmlinux
281ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
282	$(Q)$(MAKE) $(build)=arch/x86/tools posttest
283endif
284	$(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
285	$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
286	$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
287
288$(BOOT_TARGETS): vmlinux
289	$(Q)$(MAKE) $(build)=$(boot) $@
290
291PHONY += install
292install:
293	$(Q)$(MAKE) $(build)=$(boot) $@
294
295PHONY += vdso_install
296vdso_install:
297	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
298
299archprepare: checkbin
300checkbin:
301ifndef CONFIG_CC_HAS_ASM_GOTO
302	@echo Compiler lacks asm-goto support.
303	@exit 1
304endif
305ifdef CONFIG_RETPOLINE
306ifeq ($(RETPOLINE_CFLAGS),)
307	@echo "You are building kernel with non-retpoline compiler." >&2
308	@echo "Please update your compiler." >&2
309	@false
310endif
311endif
312
313archclean:
314	$(Q)rm -rf $(objtree)/arch/i386
315	$(Q)rm -rf $(objtree)/arch/x86_64
316	$(Q)$(MAKE) $(clean)=$(boot)
317	$(Q)$(MAKE) $(clean)=arch/x86/tools
318
319define archhelp
320  echo  '* bzImage      - Compressed kernel image (arch/x86/boot/bzImage)'
321  echo  '  install      - Install kernel using'
322  echo  '                  (your) ~/bin/$(INSTALLKERNEL) or'
323  echo  '                  (distribution) /sbin/$(INSTALLKERNEL) or'
324  echo  '                  install to $$(INSTALL_PATH) and run lilo'
325  echo  '  fdimage      - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
326  echo  '  fdimage144   - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
327  echo  '  fdimage288   - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
328  echo  '  isoimage     - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
329  echo  '                  bzdisk/fdimage*/isoimage also accept:'
330  echo  '                  FDARGS="..."  arguments for the booted kernel'
331  echo  '                  FDINITRD=file initrd for the booted kernel'
332endef
333