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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 | 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
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 := -std=gnu11 -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)
56ifdef CONFIG_CC_IS_CLANG
57REALMODE_CFLAGS += -Wno-gnu
58endif
59export REALMODE_CFLAGS
60
61# BITS is used as extension for files which are available in a 32 bit
62# and a 64 bit version to simplify shared Makefiles.
63# e.g.: obj-y += foo_$(BITS).o
64export BITS
65
66#
67# Prevent GCC from generating any FP code by mistake.
68#
69# This must happen before we try the -mpreferred-stack-boundary, see:
70#
71# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
72#
73KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
74KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json
75KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
76
77ifeq ($(CONFIG_X86_KERNEL_IBT),y)
78#
79# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate
80# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK
81# for jump-tables, as such, disable jump-tables for now.
82#
83# (jump-tables are implicitly disabled by RETPOLINE)
84#
85# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816
86#
87KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables)
88KBUILD_RUSTFLAGS += -Zcf-protection=branch -Zno-jump-tables
89else
90KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
91endif
92
93ifeq ($(CONFIG_X86_32),y)
94 BITS := 32
95 UTS_MACHINE := i386
96 CHECKFLAGS += -D__i386__
97
98 KBUILD_AFLAGS += -m32
99 KBUILD_CFLAGS += -m32
100
101 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
102
103 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
104 # with nonstandard options
105 KBUILD_CFLAGS += -fno-pic
106
107 # Align the stack to the register width instead of using the default
108 # alignment of 16 bytes. This reduces stack usage and the number of
109 # alignment instructions.
110 KBUILD_CFLAGS += $(cc_stack_align4)
111
112 # CPU-specific tuning. Anything which can be shared with UML should go here.
113 include $(srctree)/arch/x86/Makefile_32.cpu
114 KBUILD_CFLAGS += $(cflags-y)
115
116 # temporary until string.h is fixed
117 KBUILD_CFLAGS += -ffreestanding
118
119 ifeq ($(CONFIG_STACKPROTECTOR),y)
120 ifeq ($(CONFIG_SMP),y)
121 KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard
122 else
123 KBUILD_CFLAGS += -mstack-protector-guard=global
124 endif
125 endif
126else
127 BITS := 64
128 UTS_MACHINE := x86_64
129 CHECKFLAGS += -D__x86_64__
130
131 KBUILD_AFLAGS += -m64
132 KBUILD_CFLAGS += -m64
133
134 # Align jump targets to 1 byte, not the default 16 bytes:
135 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
136
137 # Pack loops tightly as well:
138 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
139
140 # Don't autogenerate traditional x87 instructions
141 KBUILD_CFLAGS += -mno-80387
142 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
143
144 # By default gcc and clang use a stack alignment of 16 bytes for x86.
145 # However the standard kernel entry on x86-64 leaves the stack on an
146 # 8-byte boundary. If the compiler isn't informed about the actual
147 # alignment it will generate extra alignment instructions for the
148 # default alignment which keep the stack *mis*aligned.
149 # Furthermore an alignment to the register width reduces stack usage
150 # and the number of alignment instructions.
151 KBUILD_CFLAGS += $(cc_stack_align8)
152
153 # Use -mskip-rax-setup if supported.
154 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
155
156 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
157 cflags-$(CONFIG_MK8) += -march=k8
158 cflags-$(CONFIG_MPSC) += -march=nocona
159 cflags-$(CONFIG_MCORE2) += -march=core2
160 cflags-$(CONFIG_MATOM) += -march=atom
161 cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic
162 KBUILD_CFLAGS += $(cflags-y)
163
164 rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8
165 rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona
166 rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2
167 rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom
168 rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic
169 KBUILD_RUSTFLAGS += $(rustflags-y)
170
171 KBUILD_CFLAGS += -mno-red-zone
172 KBUILD_CFLAGS += -mcmodel=kernel
173 KBUILD_RUSTFLAGS += -Cno-redzone=y
174 KBUILD_RUSTFLAGS += -Ccode-model=kernel
175endif
176
177#
178# If the function graph tracer is used with mcount instead of fentry,
179# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
180# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
181#
182ifdef CONFIG_FUNCTION_GRAPH_TRACER
183 ifndef CONFIG_HAVE_FENTRY
184 ACCUMULATE_OUTGOING_ARGS := 1
185 endif
186endif
187
188ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
189 # This compiler flag is not supported by Clang:
190 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
191endif
192
193# Workaround for a gcc prelease that unfortunately was shipped in a suse release
194KBUILD_CFLAGS += -Wno-sign-compare
195#
196KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
197
198# Avoid indirect branches in kernel to deal with Spectre
199ifdef CONFIG_MITIGATION_RETPOLINE
200 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
201 # Additionally, avoid generating expensive indirect jumps which
202 # are subject to retpolines for small number of switch cases.
203 # clang turns off jump table generation by default when under
204 # retpoline builds, however, gcc does not for x86. This has
205 # only been fixed starting from gcc stable version 8.4.0 and
206 # onwards, but not for older ones. See gcc bug #86952.
207 ifndef CONFIG_CC_IS_CLANG
208 KBUILD_CFLAGS += -fno-jump-tables
209 endif
210endif
211
212ifdef CONFIG_MITIGATION_SLS
213 KBUILD_CFLAGS += -mharden-sls=all
214endif
215
216ifdef CONFIG_CALL_PADDING
217PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
218KBUILD_CFLAGS += $(PADDING_CFLAGS)
219export PADDING_CFLAGS
220endif
221
222KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
223
224ifdef CONFIG_X86_NEED_RELOCS
225LDFLAGS_vmlinux := --emit-relocs --discard-none
226else
227LDFLAGS_vmlinux :=
228endif
229
230#
231# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to
232# the linker to force 2MB page size regardless of the default page size used
233# by the linker.
234#
235ifdef CONFIG_X86_64
236LDFLAGS_vmlinux += -z max-page-size=0x200000
237endif
238
239
240archscripts: scripts_basic
241 $(Q)$(MAKE) $(build)=arch/x86/tools relocs
242
243###
244# Syscall table generation
245
246archheaders:
247 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
248
249###
250# Kernel objects
251
252libs-y += arch/x86/lib
253
254# drivers-y are linked after core-y
255drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
256drivers-$(CONFIG_PCI) += arch/x86/pci/
257
258# suspend and hibernation support
259drivers-$(CONFIG_PM) += arch/x86/power/
260
261drivers-$(CONFIG_FB_CORE) += arch/x86/video/
262
263####
264# boot loader support. Several targets are kept for legacy purposes
265
266boot := arch/x86/boot
267
268BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
269
270PHONY += bzImage $(BOOT_TARGETS)
271
272# Default kernel to build
273all: bzImage
274
275# KBUILD_IMAGE specify target image being built
276KBUILD_IMAGE := $(boot)/bzImage
277
278bzImage: vmlinux
279ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
280 $(Q)$(MAKE) $(build)=arch/x86/tools posttest
281endif
282 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
283 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
284 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
285
286$(BOOT_TARGETS): vmlinux
287 $(Q)$(MAKE) $(build)=$(boot) $@
288
289PHONY += install
290install:
291 $(call cmd,install)
292
293vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg
294vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg
295vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32.so.dbg
296
297archprepare: checkbin
298checkbin:
299ifdef CONFIG_MITIGATION_RETPOLINE
300ifeq ($(RETPOLINE_CFLAGS),)
301 @echo "You are building kernel with non-retpoline compiler." >&2
302 @echo "Please update your compiler." >&2
303 @false
304endif
305endif
306
307ifdef CONFIG_UNWINDER_ORC
308orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
309orc_hash_sh := $(srctree)/scripts/orc_hash.sh
310targets += $(orc_hash_h)
311quiet_cmd_orc_hash = GEN $@
312 cmd_orc_hash = mkdir -p $(dir $@); \
313 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@
314$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE
315 $(call if_changed,orc_hash)
316archprepare: $(orc_hash_h)
317endif
318
319archclean:
320 $(Q)rm -rf $(objtree)/arch/i386
321 $(Q)rm -rf $(objtree)/arch/x86_64
322
323define archhelp
324 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)'
325 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
326 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to '
327 echo ' $$(INSTALL_PATH) and run lilo'
328 echo ''
329 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
330 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
331 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
332 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
333 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
334 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:'
335 echo ' FDARGS="..." arguments for the booted kernel'
336 echo ' FDINITRD=file initrd for the booted kernel'
337
338endef