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 | sed -e 's/i.86/i386/'),i386)
7 KBUILD_DEFCONFIG := i386_defconfig
8 else
9 KBUILD_DEFCONFIG := x86_64_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_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register)
18endif
19ifdef CONFIG_CC_IS_CLANG
20RETPOLINE_CFLAGS := -mretpoline-external-thunk
21RETPOLINE_VDSO_CFLAGS := -mretpoline
22endif
23RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch-cs-prefix)
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
308ifdef CONFIG_UNWINDER_ORC
309orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
310orc_hash_sh := $(srctree)/scripts/orc_hash.sh
311targets += $(orc_hash_h)
312quiet_cmd_orc_hash = GEN $@
313 cmd_orc_hash = mkdir -p $(dir $@); \
314 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@
315$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE
316 $(call if_changed,orc_hash)
317archprepare: $(orc_hash_h)
318endif
319
320archclean:
321 $(Q)rm -rf $(objtree)/arch/i386
322 $(Q)rm -rf $(objtree)/arch/x86_64
323
324define archhelp
325 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)'
326 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
327 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to '
328 echo ' $$(INSTALL_PATH) and run lilo'
329 echo ''
330 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
331 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
332 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
333 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
334 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
335 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:'
336 echo ' FDARGS="..." arguments for the booted kernel'
337 echo ' FDINITRD=file initrd for the booted kernel'
338 echo ''
339 echo ' kvm_guest.config - Enable Kconfig items for running this kernel as a KVM guest'
340 echo ' xen.config - Enable Kconfig items for running this kernel as a Xen guest'
341 echo ' x86_debug.config - Enable tip tree debugging options for testing'
342
343endef