Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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.
27REALMODE_CFLAGS := -m16 -g -Os -DDISABLE_BRANCH_PROFILING \
28 -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
29 -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
30 -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none)
31
32REALMODE_CFLAGS += -ffreestanding
33REALMODE_CFLAGS += -fno-stack-protector
34REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member)
35REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
36REALMODE_CFLAGS += $(CLANG_FLAGS)
37export REALMODE_CFLAGS
38
39# BITS is used as extension for files which are available in a 32 bit
40# and a 64 bit version to simplify shared Makefiles.
41# e.g.: obj-y += foo_$(BITS).o
42export BITS
43
44#
45# Prevent GCC from generating any FP code by mistake.
46#
47# This must happen before we try the -mpreferred-stack-boundary, see:
48#
49# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
50#
51KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
52KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
53
54# Intel CET isn't enabled in the kernel
55KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
56
57ifeq ($(CONFIG_X86_32),y)
58 BITS := 32
59 UTS_MACHINE := i386
60 CHECKFLAGS += -D__i386__
61
62 biarch := $(call cc-option,-m32)
63 KBUILD_AFLAGS += $(biarch)
64 KBUILD_CFLAGS += $(biarch)
65
66 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
67
68 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
69 # with nonstandard options
70 KBUILD_CFLAGS += -fno-pic
71
72 # Align the stack to the register width instead of using the default
73 # alignment of 16 bytes. This reduces stack usage and the number of
74 # alignment instructions.
75 KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
76
77 # CPU-specific tuning. Anything which can be shared with UML should go here.
78 include arch/x86/Makefile_32.cpu
79 KBUILD_CFLAGS += $(cflags-y)
80
81 # temporary until string.h is fixed
82 KBUILD_CFLAGS += -ffreestanding
83
84 ifeq ($(CONFIG_STACKPROTECTOR),y)
85 ifeq ($(CONFIG_SMP),y)
86 KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard
87 else
88 KBUILD_CFLAGS += -mstack-protector-guard=global
89 endif
90 endif
91else
92 BITS := 64
93 UTS_MACHINE := x86_64
94 CHECKFLAGS += -D__x86_64__
95
96 biarch := -m64
97 KBUILD_AFLAGS += -m64
98 KBUILD_CFLAGS += -m64
99
100 # Align jump targets to 1 byte, not the default 16 bytes:
101 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
102
103 # Pack loops tightly as well:
104 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
105
106 # Don't autogenerate traditional x87 instructions
107 KBUILD_CFLAGS += $(call cc-option,-mno-80387)
108 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
109
110 # By default gcc and clang use a stack alignment of 16 bytes for x86.
111 # However the standard kernel entry on x86-64 leaves the stack on an
112 # 8-byte boundary. If the compiler isn't informed about the actual
113 # alignment it will generate extra alignment instructions for the
114 # default alignment which keep the stack *mis*aligned.
115 # Furthermore an alignment to the register width reduces stack usage
116 # and the number of alignment instructions.
117 KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
118
119 # Use -mskip-rax-setup if supported.
120 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
121
122 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
123 cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
124 cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
125
126 cflags-$(CONFIG_MCORE2) += \
127 $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
128 cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
129 $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
130 cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
131 KBUILD_CFLAGS += $(cflags-y)
132
133 KBUILD_CFLAGS += -mno-red-zone
134 KBUILD_CFLAGS += -mcmodel=kernel
135endif
136
137ifdef CONFIG_X86_X32
138 x32_ld_ok := $(call try-run,\
139 /bin/echo -e '1: .quad 1b' | \
140 $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
141 $(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMP.o" && \
142 $(LD) -m elf32_x86_64 "$$TMP.o" -o "$$TMP",y,n)
143 ifeq ($(x32_ld_ok),y)
144 CONFIG_X86_X32_ABI := y
145 KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
146 KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
147 else
148 $(warning CONFIG_X86_X32 enabled but no binutils support)
149 endif
150endif
151export CONFIG_X86_X32_ABI
152
153#
154# If the function graph tracer is used with mcount instead of fentry,
155# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
156# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
157#
158ifdef CONFIG_FUNCTION_GRAPH_TRACER
159 ifndef CONFIG_HAVE_FENTRY
160 ACCUMULATE_OUTGOING_ARGS := 1
161 else
162 ifeq ($(call cc-option-yn, -mfentry), n)
163 ACCUMULATE_OUTGOING_ARGS := 1
164
165 # GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
166 # If '-Os' is enabled, disable it and print a warning.
167 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
168 undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
169 $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE. Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
170 endif
171
172 endif
173 endif
174endif
175
176ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
177 # This compiler flag is not supported by Clang:
178 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
179endif
180
181# Workaround for a gcc prelease that unfortunately was shipped in a suse release
182KBUILD_CFLAGS += -Wno-sign-compare
183#
184KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
185
186# Avoid indirect branches in kernel to deal with Spectre
187ifdef CONFIG_RETPOLINE
188 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
189 # Additionally, avoid generating expensive indirect jumps which
190 # are subject to retpolines for small number of switch cases.
191 # clang turns off jump table generation by default when under
192 # retpoline builds, however, gcc does not for x86. This has
193 # only been fixed starting from gcc stable version 8.4.0 and
194 # onwards, but not for older ones. See gcc bug #86952.
195 ifndef CONFIG_CC_IS_CLANG
196 KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
197 endif
198endif
199
200KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
201
202ifdef CONFIG_LTO_CLANG
203ifeq ($(shell test $(CONFIG_LLD_VERSION) -lt 130000; echo $$?),0)
204KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
205endif
206endif
207
208ifdef CONFIG_X86_NEED_RELOCS
209LDFLAGS_vmlinux := --emit-relocs --discard-none
210else
211LDFLAGS_vmlinux :=
212endif
213
214#
215# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to
216# the linker to force 2MB page size regardless of the default page size used
217# by the linker.
218#
219ifdef CONFIG_X86_64
220LDFLAGS_vmlinux += -z max-page-size=0x200000
221endif
222
223
224archscripts: scripts_basic
225 $(Q)$(MAKE) $(build)=arch/x86/tools relocs
226
227###
228# Syscall table generation
229
230archheaders:
231 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
232
233###
234# Kernel objects
235
236head-y := arch/x86/kernel/head_$(BITS).o
237head-y += arch/x86/kernel/head$(BITS).o
238head-y += arch/x86/kernel/ebda.o
239head-y += arch/x86/kernel/platform-quirks.o
240
241libs-y += arch/x86/lib/
242
243# drivers-y are linked after core-y
244drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
245drivers-$(CONFIG_PCI) += arch/x86/pci/
246
247# suspend and hibernation support
248drivers-$(CONFIG_PM) += arch/x86/power/
249
250drivers-$(CONFIG_FB) += arch/x86/video/
251
252####
253# boot loader support. Several targets are kept for legacy purposes
254
255boot := arch/x86/boot
256
257BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
258
259PHONY += bzImage $(BOOT_TARGETS)
260
261# Default kernel to build
262all: bzImage
263
264# KBUILD_IMAGE specify target image being built
265KBUILD_IMAGE := $(boot)/bzImage
266
267bzImage: vmlinux
268ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
269 $(Q)$(MAKE) $(build)=arch/x86/tools posttest
270endif
271 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
272 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
273 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
274
275$(BOOT_TARGETS): vmlinux
276 $(Q)$(MAKE) $(build)=$(boot) $@
277
278PHONY += install bzlilo
279install bzlilo:
280 $(Q)$(MAKE) $(build)=$(boot) $@
281
282PHONY += vdso_install
283vdso_install:
284 $(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
285
286archprepare: checkbin
287checkbin:
288ifndef CONFIG_CC_HAS_ASM_GOTO
289 @echo Compiler lacks asm-goto support.
290 @exit 1
291endif
292ifdef CONFIG_RETPOLINE
293ifeq ($(RETPOLINE_CFLAGS),)
294 @echo "You are building kernel with non-retpoline compiler." >&2
295 @echo "Please update your compiler." >&2
296 @false
297endif
298endif
299
300archclean:
301 $(Q)rm -rf $(objtree)/arch/i386
302 $(Q)rm -rf $(objtree)/arch/x86_64
303 $(Q)$(MAKE) $(clean)=$(boot)
304 $(Q)$(MAKE) $(clean)=arch/x86/tools
305
306define archhelp
307 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)'
308 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
309 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to '
310 echo ' $$(INSTALL_PATH) and run lilo'
311 echo ''
312 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
313 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
314 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
315 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
316 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
317 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:'
318 echo ' FDARGS="..." arguments for the booted kernel'
319 echo ' FDINITRD=file initrd for the booted kernel'
320 echo ''
321 echo ' kvm_guest.config - Enable Kconfig items for running this kernel as a KVM guest'
322 echo ' xen.config - Enable Kconfig items for running this kernel as a Xen guest'
323
324endef