Loading...
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_MITIGATION_RETHUNK
26RETHUNK_CFLAGS := -mfunction-return=thunk-extern
27RETHUNK_RUSTFLAGS := -Zfunction-return=thunk-extern
28RETPOLINE_CFLAGS += $(RETHUNK_CFLAGS)
29RETPOLINE_RUSTFLAGS += $(RETHUNK_RUSTFLAGS)
30endif
31
32export RETHUNK_CFLAGS
33export RETHUNK_RUSTFLAGS
34export RETPOLINE_CFLAGS
35export RETPOLINE_RUSTFLAGS
36export RETPOLINE_VDSO_CFLAGS
37
38# For gcc stack alignment is specified with -mpreferred-stack-boundary,
39# clang has the option -mstack-alignment for that purpose.
40ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
41 cc_stack_align4 := -mpreferred-stack-boundary=2
42 cc_stack_align8 := -mpreferred-stack-boundary=3
43else ifneq ($(call cc-option, -mstack-alignment=16),)
44 cc_stack_align4 := -mstack-alignment=4
45 cc_stack_align8 := -mstack-alignment=8
46endif
47
48# How to compile the 16-bit code. Note we always compile for -march=i386;
49# that way we can complain to the user if the CPU is insufficient.
50REALMODE_CFLAGS := -std=gnu11 -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \
51 -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
52 -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
53 -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none)
54
55REALMODE_CFLAGS += -ffreestanding
56REALMODE_CFLAGS += -fno-stack-protector
57REALMODE_CFLAGS += -Wno-address-of-packed-member
58REALMODE_CFLAGS += $(cc_stack_align4)
59REALMODE_CFLAGS += $(CLANG_FLAGS)
60ifdef CONFIG_CC_IS_CLANG
61REALMODE_CFLAGS += -Wno-gnu
62endif
63export REALMODE_CFLAGS
64
65# BITS is used as extension for files which are available in a 32 bit
66# and a 64 bit version to simplify shared Makefiles.
67# e.g.: obj-y += foo_$(BITS).o
68export BITS
69
70#
71# Prevent GCC from generating any FP code by mistake.
72#
73# This must happen before we try the -mpreferred-stack-boundary, see:
74#
75# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
76#
77KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
78KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json
79KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
80
81#
82# CFLAGS for compiling floating point code inside the kernel.
83#
84CC_FLAGS_FPU := -msse -msse2
85ifdef CONFIG_CC_IS_GCC
86# Stack alignment mismatch, proceed with caution.
87# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3
88# (8B stack alignment).
89# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
90#
91# The "-msse" in the first argument is there so that the
92# -mpreferred-stack-boundary=3 build error:
93#
94# -mpreferred-stack-boundary=3 is not between 4 and 12
95#
96# can be triggered. Otherwise gcc doesn't complain.
97CC_FLAGS_FPU += -mhard-float
98CC_FLAGS_FPU += $(call cc-option,-msse -mpreferred-stack-boundary=3,-mpreferred-stack-boundary=4)
99endif
100
101ifeq ($(CONFIG_X86_KERNEL_IBT),y)
102#
103# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate
104# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK
105# for jump-tables, as such, disable jump-tables for now.
106#
107# (jump-tables are implicitly disabled by RETPOLINE)
108#
109# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816
110#
111KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables)
112KBUILD_RUSTFLAGS += -Zcf-protection=branch -Zno-jump-tables
113else
114KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
115endif
116
117ifeq ($(CONFIG_X86_32),y)
118 BITS := 32
119 UTS_MACHINE := i386
120 CHECKFLAGS += -D__i386__
121
122 KBUILD_AFLAGS += -m32
123 KBUILD_CFLAGS += -m32
124
125 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
126
127 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
128 # with nonstandard options
129 KBUILD_CFLAGS += -fno-pic
130
131 # Align the stack to the register width instead of using the default
132 # alignment of 16 bytes. This reduces stack usage and the number of
133 # alignment instructions.
134 KBUILD_CFLAGS += $(cc_stack_align4)
135
136 # CPU-specific tuning. Anything which can be shared with UML should go here.
137 include $(srctree)/arch/x86/Makefile_32.cpu
138 KBUILD_CFLAGS += $(cflags-y)
139
140 # temporary until string.h is fixed
141 KBUILD_CFLAGS += -ffreestanding
142
143 ifeq ($(CONFIG_STACKPROTECTOR),y)
144 ifeq ($(CONFIG_SMP),y)
145 KBUILD_CFLAGS += -mstack-protector-guard-reg=fs \
146 -mstack-protector-guard-symbol=__ref_stack_chk_guard
147 else
148 KBUILD_CFLAGS += -mstack-protector-guard=global
149 endif
150 endif
151else
152 BITS := 64
153 UTS_MACHINE := x86_64
154 CHECKFLAGS += -D__x86_64__
155
156 KBUILD_AFLAGS += -m64
157 KBUILD_CFLAGS += -m64
158
159 # Align jump targets to 1 byte, not the default 16 bytes:
160 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
161
162 # Pack loops tightly as well:
163 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
164
165 # Don't autogenerate traditional x87 instructions
166 KBUILD_CFLAGS += -mno-80387
167 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
168
169 # By default gcc and clang use a stack alignment of 16 bytes for x86.
170 # However the standard kernel entry on x86-64 leaves the stack on an
171 # 8-byte boundary. If the compiler isn't informed about the actual
172 # alignment it will generate extra alignment instructions for the
173 # default alignment which keep the stack *mis*aligned.
174 # Furthermore an alignment to the register width reduces stack usage
175 # and the number of alignment instructions.
176 KBUILD_CFLAGS += $(cc_stack_align8)
177
178 # Use -mskip-rax-setup if supported.
179 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
180
181 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
182 cflags-$(CONFIG_MK8) += -march=k8
183 cflags-$(CONFIG_MPSC) += -march=nocona
184 cflags-$(CONFIG_MCORE2) += -march=core2
185 cflags-$(CONFIG_MATOM) += -march=atom
186 cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic
187 KBUILD_CFLAGS += $(cflags-y)
188
189 rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8
190 rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona
191 rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2
192 rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom
193 rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic
194 KBUILD_RUSTFLAGS += $(rustflags-y)
195
196 KBUILD_CFLAGS += -mno-red-zone
197 KBUILD_CFLAGS += -mcmodel=kernel
198 KBUILD_RUSTFLAGS += -Cno-redzone=y
199 KBUILD_RUSTFLAGS += -Ccode-model=kernel
200endif
201
202#
203# If the function graph tracer is used with mcount instead of fentry,
204# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
205# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
206#
207ifdef CONFIG_FUNCTION_GRAPH_TRACER
208 ifndef CONFIG_HAVE_FENTRY
209 ACCUMULATE_OUTGOING_ARGS := 1
210 endif
211endif
212
213ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
214 # This compiler flag is not supported by Clang:
215 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
216endif
217
218# Workaround for a gcc prelease that unfortunately was shipped in a suse release
219KBUILD_CFLAGS += -Wno-sign-compare
220#
221KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
222
223# Avoid indirect branches in kernel to deal with Spectre
224ifdef CONFIG_MITIGATION_RETPOLINE
225 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
226 KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS)
227 # Additionally, avoid generating expensive indirect jumps which
228 # are subject to retpolines for small number of switch cases.
229 # LLVM turns off jump table generation by default when under
230 # retpoline builds, however, gcc does not for x86. This has
231 # only been fixed starting from gcc stable version 8.4.0 and
232 # onwards, but not for older ones. See gcc bug #86952.
233 ifndef CONFIG_CC_IS_CLANG
234 KBUILD_CFLAGS += -fno-jump-tables
235 endif
236endif
237
238ifdef CONFIG_MITIGATION_SLS
239 KBUILD_CFLAGS += -mharden-sls=all
240endif
241
242ifdef CONFIG_CALL_PADDING
243PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
244KBUILD_CFLAGS += $(PADDING_CFLAGS)
245export PADDING_CFLAGS
246
247PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
248KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS)
249export PADDING_RUSTFLAGS
250endif
251
252KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
253
254ifdef CONFIG_X86_NEED_RELOCS
255LDFLAGS_vmlinux := --emit-relocs --discard-none
256else
257LDFLAGS_vmlinux :=
258endif
259
260#
261# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to
262# the linker to force 2MB page size regardless of the default page size used
263# by the linker.
264#
265ifdef CONFIG_X86_64
266LDFLAGS_vmlinux += -z max-page-size=0x200000
267endif
268
269
270archscripts: scripts_basic
271 $(Q)$(MAKE) $(build)=arch/x86/tools relocs
272
273###
274# Syscall table generation
275
276archheaders:
277 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
278
279###
280# Kernel objects
281
282libs-y += arch/x86/lib
283
284# drivers-y are linked after core-y
285drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
286drivers-$(CONFIG_PCI) += arch/x86/pci/
287
288# suspend and hibernation support
289drivers-$(CONFIG_PM) += arch/x86/power/
290
291drivers-$(CONFIG_VIDEO) += arch/x86/video/
292
293####
294# boot loader support. Several targets are kept for legacy purposes
295
296boot := arch/x86/boot
297
298BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
299
300PHONY += bzImage $(BOOT_TARGETS)
301
302# Default kernel to build
303all: bzImage
304
305# KBUILD_IMAGE specify target image being built
306KBUILD_IMAGE := $(boot)/bzImage
307
308bzImage: vmlinux
309ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
310 $(Q)$(MAKE) $(build)=arch/x86/tools posttest
311endif
312 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
313 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
314 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
315
316$(BOOT_TARGETS): vmlinux
317 $(Q)$(MAKE) $(build)=$(boot) $@
318
319PHONY += install
320install:
321 $(call cmd,install)
322
323vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg
324vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg
325vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32.so.dbg
326
327archprepare: checkbin
328checkbin:
329ifdef CONFIG_MITIGATION_RETPOLINE
330ifeq ($(RETPOLINE_CFLAGS),)
331 @echo "You are building kernel with non-retpoline compiler." >&2
332 @echo "Please update your compiler." >&2
333 @false
334endif
335endif
336
337ifdef CONFIG_UNWINDER_ORC
338orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
339orc_hash_sh := $(srctree)/scripts/orc_hash.sh
340targets += $(orc_hash_h)
341quiet_cmd_orc_hash = GEN $@
342 cmd_orc_hash = mkdir -p $(dir $@); \
343 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@
344$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE
345 $(call if_changed,orc_hash)
346archprepare: $(orc_hash_h)
347endif
348
349archclean:
350 $(Q)rm -rf $(objtree)/arch/i386
351 $(Q)rm -rf $(objtree)/arch/x86_64
352
353define archhelp
354 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)'
355 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
356 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to '
357 echo ' $$(INSTALL_PATH) and run lilo'
358 echo ''
359 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
360 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
361 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
362 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
363 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
364 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:'
365 echo ' FDARGS="..." arguments for the booted kernel'
366 echo ' FDINITRD=file initrd for the booted kernel'
367
368endef
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 += -ffreestanding
40REALMODE_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
50#
51# Prevent GCC from generating any FP code by mistake.
52#
53# This must happen before we try the -mpreferred-stack-boundary, see:
54#
55# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
56#
57KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
58KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
59
60ifeq ($(CONFIG_X86_32),y)
61 BITS := 32
62 UTS_MACHINE := i386
63 CHECKFLAGS += -D__i386__
64
65 biarch := $(call cc-option,-m32)
66 KBUILD_AFLAGS += $(biarch)
67 KBUILD_CFLAGS += $(biarch)
68
69 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
70
71 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
72 # with nonstandard options
73 KBUILD_CFLAGS += -fno-pic
74
75 # Align the stack to the register width instead of using the default
76 # alignment of 16 bytes. This reduces stack usage and the number of
77 # alignment instructions.
78 KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4))
79
80 # CPU-specific tuning. Anything which can be shared with UML should go here.
81 include arch/x86/Makefile_32.cpu
82 KBUILD_CFLAGS += $(cflags-y)
83
84 # temporary until string.h is fixed
85 KBUILD_CFLAGS += -ffreestanding
86else
87 BITS := 64
88 UTS_MACHINE := x86_64
89 CHECKFLAGS += -D__x86_64__
90
91 biarch := -m64
92 KBUILD_AFLAGS += -m64
93 KBUILD_CFLAGS += -m64
94
95 # Align jump targets to 1 byte, not the default 16 bytes:
96 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
97
98 # Pack loops tightly as well:
99 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
100
101 # Don't autogenerate traditional x87 instructions
102 KBUILD_CFLAGS += $(call cc-option,-mno-80387)
103 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
104
105 # By default gcc and clang use a stack alignment of 16 bytes for x86.
106 # However the standard kernel entry on x86-64 leaves the stack on an
107 # 8-byte boundary. If the compiler isn't informed about the actual
108 # alignment it will generate extra alignment instructions for the
109 # default alignment which keep the stack *mis*aligned.
110 # Furthermore an alignment to the register width reduces stack usage
111 # and the number of alignment instructions.
112 KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8))
113
114 # Use -mskip-rax-setup if supported.
115 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
116
117 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
118 cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8)
119 cflags-$(CONFIG_MPSC) += $(call cc-option,-march=nocona)
120
121 cflags-$(CONFIG_MCORE2) += \
122 $(call cc-option,-march=core2,$(call cc-option,-mtune=generic))
123 cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom) \
124 $(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
125 cflags-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=generic)
126 KBUILD_CFLAGS += $(cflags-y)
127
128 KBUILD_CFLAGS += -mno-red-zone
129 KBUILD_CFLAGS += -mcmodel=kernel
130endif
131
132ifdef CONFIG_X86_X32
133 x32_ld_ok := $(call try-run,\
134 /bin/echo -e '1: .quad 1b' | \
135 $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" - && \
136 $(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMPO" && \
137 $(LD) -m elf32_x86_64 "$$TMPO" -o "$$TMP",y,n)
138 ifeq ($(x32_ld_ok),y)
139 CONFIG_X86_X32_ABI := y
140 KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
141 KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
142 else
143 $(warning CONFIG_X86_X32 enabled but no binutils support)
144 endif
145endif
146export CONFIG_X86_X32_ABI
147
148#
149# If the function graph tracer is used with mcount instead of fentry,
150# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
151# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
152#
153ifdef CONFIG_FUNCTION_GRAPH_TRACER
154 ifndef CONFIG_HAVE_FENTRY
155 ACCUMULATE_OUTGOING_ARGS := 1
156 else
157 ifeq ($(call cc-option-yn, -mfentry), n)
158 ACCUMULATE_OUTGOING_ARGS := 1
159
160 # GCC ignores '-maccumulate-outgoing-args' when used with '-Os'.
161 # If '-Os' is enabled, disable it and print a warning.
162 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
163 undefine CONFIG_CC_OPTIMIZE_FOR_SIZE
164 $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE. Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.)
165 endif
166
167 endif
168 endif
169endif
170
171ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
172 # This compiler flag is not supported by Clang:
173 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
174endif
175
176# Workaround for a gcc prelease that unfortunately was shipped in a suse release
177KBUILD_CFLAGS += -Wno-sign-compare
178#
179KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
180
181# Avoid indirect branches in kernel to deal with Spectre
182ifdef CONFIG_RETPOLINE
183 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
184 # Additionally, avoid generating expensive indirect jumps which
185 # are subject to retpolines for small number of switch cases.
186 # clang turns off jump table generation by default when under
187 # retpoline builds, however, gcc does not for x86. This has
188 # only been fixed starting from gcc stable version 8.4.0 and
189 # onwards, but not for older ones. See gcc bug #86952.
190 ifndef CONFIG_CC_IS_CLANG
191 KBUILD_CFLAGS += $(call cc-option,-fno-jump-tables)
192 endif
193endif
194
195KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
196
197ifdef CONFIG_X86_NEED_RELOCS
198LDFLAGS_vmlinux := --emit-relocs --discard-none
199else
200LDFLAGS_vmlinux :=
201endif
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
209LDFLAGS_vmlinux += -z max-page-size=0x200000
210endif
211
212archscripts: scripts_basic
213 $(Q)$(MAKE) $(build)=arch/x86/tools relocs
214
215###
216# Syscall table generation
217
218archheaders:
219 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
220
221###
222# Kernel objects
223
224head-y := arch/x86/kernel/head_$(BITS).o
225head-y += arch/x86/kernel/head$(BITS).o
226head-y += arch/x86/kernel/ebda.o
227head-y += arch/x86/kernel/platform-quirks.o
228
229libs-y += arch/x86/lib
230
231# See arch/x86/Kbuild for content of core part of the kernel
232core-y += arch/x86/
233
234# drivers-y are linked after core-y
235drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
236drivers-$(CONFIG_PCI) += arch/x86/pci/
237
238# must be linked after kernel
239drivers-$(CONFIG_OPROFILE) += arch/x86/oprofile/
240
241# suspend and hibernation support
242drivers-$(CONFIG_PM) += arch/x86/power/
243
244drivers-$(CONFIG_FB) += arch/x86/video/
245
246####
247# boot loader support. Several targets are kept for legacy purposes
248
249boot := arch/x86/boot
250
251BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 isoimage
252
253PHONY += bzImage $(BOOT_TARGETS)
254
255# Default kernel to build
256all: bzImage
257
258# KBUILD_IMAGE specify target image being built
259KBUILD_IMAGE := $(boot)/bzImage
260
261bzImage: vmlinux
262ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
263 $(Q)$(MAKE) $(build)=arch/x86/tools posttest
264endif
265 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
266 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
267 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
268
269$(BOOT_TARGETS): vmlinux
270 $(Q)$(MAKE) $(build)=$(boot) $@
271
272PHONY += install bzlilo
273install bzlilo:
274 $(Q)$(MAKE) $(build)=$(boot) $@
275
276PHONY += vdso_install
277vdso_install:
278 $(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
279
280archprepare: checkbin
281checkbin:
282ifndef CONFIG_CC_HAS_ASM_GOTO
283 @echo Compiler lacks asm-goto support.
284 @exit 1
285endif
286ifdef CONFIG_RETPOLINE
287ifeq ($(RETPOLINE_CFLAGS),)
288 @echo "You are building kernel with non-retpoline compiler." >&2
289 @echo "Please update your compiler." >&2
290 @false
291endif
292endif
293
294archclean:
295 $(Q)rm -rf $(objtree)/arch/i386
296 $(Q)rm -rf $(objtree)/arch/x86_64
297 $(Q)$(MAKE) $(clean)=$(boot)
298 $(Q)$(MAKE) $(clean)=arch/x86/tools
299
300define archhelp
301 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)'
302 echo ' install - Install kernel using'
303 echo ' (your) ~/bin/$(INSTALLKERNEL) or'
304 echo ' (distribution) /sbin/$(INSTALLKERNEL) or'
305 echo ' install to $$(INSTALL_PATH) and run lilo'
306 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
307 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
308 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
309 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
310 echo ' bzdisk/fdimage*/isoimage also accept:'
311 echo ' FDARGS="..." arguments for the booted kernel'
312 echo ' FDINITRD=file initrd for the booted kernel'
313endef