1 # SPDX-License-Identifier: GPL-2.0
2 # Unified Makefile for i386 and x86_64
3 
4 # select defconfig based on actual architecture
5 ifeq ($(ARCH),x86)
6   ifeq ($(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
11 else
12         KBUILD_DEFCONFIG := $(ARCH)_defconfig
13 endif
14 
15 ifdef CONFIG_CC_IS_GCC
16 RETPOLINE_CFLAGS	:= $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
17 RETPOLINE_VDSO_CFLAGS	:= $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register)
18 endif
19 ifdef CONFIG_CC_IS_CLANG
20 RETPOLINE_CFLAGS	:= -mretpoline-external-thunk
21 RETPOLINE_VDSO_CFLAGS	:= -mretpoline
22 endif
23 RETPOLINE_CFLAGS	+= $(call cc-option,-mindirect-branch-cs-prefix)
24 
25 ifdef CONFIG_MITIGATION_RETHUNK
26 RETHUNK_CFLAGS		:= -mfunction-return=thunk-extern
27 RETHUNK_RUSTFLAGS	:= -Zfunction-return=thunk-extern
28 RETPOLINE_CFLAGS	+= $(RETHUNK_CFLAGS)
29 RETPOLINE_RUSTFLAGS	+= $(RETHUNK_RUSTFLAGS)
30 endif
31 
32 export RETHUNK_CFLAGS
33 export RETHUNK_RUSTFLAGS
34 export RETPOLINE_CFLAGS
35 export RETPOLINE_RUSTFLAGS
36 export RETPOLINE_VDSO_CFLAGS
37 
38 # For gcc stack alignment is specified with -mpreferred-stack-boundary,
39 # clang has the option -mstack-alignment for that purpose.
40 ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
41       cc_stack_align4 := -mpreferred-stack-boundary=2
42       cc_stack_align8 := -mpreferred-stack-boundary=3
43 else ifneq ($(call cc-option, -mstack-alignment=16),)
44       cc_stack_align4 := -mstack-alignment=4
45       cc_stack_align8 := -mstack-alignment=8
46 endif
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.
50 REALMODE_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 
55 REALMODE_CFLAGS += -ffreestanding
56 REALMODE_CFLAGS += -fno-stack-protector
57 REALMODE_CFLAGS += -Wno-address-of-packed-member
58 REALMODE_CFLAGS += $(cc_stack_align4)
59 REALMODE_CFLAGS += $(CLANG_FLAGS)
60 ifdef CONFIG_CC_IS_CLANG
61 REALMODE_CFLAGS += -Wno-gnu
62 endif
63 export REALMODE_CFLAGS
64 
65 # BITS is used as extension for files which are available in a 32 bit
66 # and a 64 bit version to simplify shared Makefiles.
67 # e.g.: obj-y += foo_$(BITS).o
68 export 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 #
77 KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
78 KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json
79 KBUILD_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 #
84 CC_FLAGS_FPU := -msse -msse2
85 ifdef 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.
97 CC_FLAGS_FPU += -mhard-float
98 CC_FLAGS_FPU += $(call cc-option,-msse -mpreferred-stack-boundary=3,-mpreferred-stack-boundary=4)
99 endif
100 
101 ifeq ($(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 #
111 KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables)
112 KBUILD_RUSTFLAGS += -Zcf-protection=branch -Zno-jump-tables
113 else
114 KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
115 endif
116 
117 ifeq ($(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
151 else
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 += $(rustflags-y)
195 
196         KBUILD_CFLAGS += -mno-red-zone
197         KBUILD_CFLAGS += -mcmodel=kernel
198         KBUILD_RUSTFLAGS += -Cno-redzone=y
199         KBUILD_RUSTFLAGS += -Ccode-model=kernel
200 endif
201 
202 #
203 # If the function graph tracer is used with mcount instead of fentry,
204 # '-maccumulate-outgoing-args' is needed to prevent a GCC bug
205 # (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
206 #
207 ifdef CONFIG_FUNCTION_GRAPH_TRACER
208   ifndef CONFIG_HAVE_FENTRY
209 	ACCUMULATE_OUTGOING_ARGS := 1
210   endif
211 endif
212 
213 ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
214 	# This compiler flag is not supported by Clang:
215 	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
216 endif
217 
218 # Workaround for a gcc prelease that unfortunately was shipped in a suse release
219 KBUILD_CFLAGS += -Wno-sign-compare
220 #
221 KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
222 
223 # Avoid indirect branches in kernel to deal with Spectre
224 ifdef CONFIG_MITIGATION_RETPOLINE
225   KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
226   KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS)
227   # Additionally, avoid generating expensive indirect jumps which
228   # are subject to retpolines for small number of switch cases.
229   # LLVM turns off jump table generation by default when under
230   # retpoline builds, however, gcc does not for x86. This has
231   # only been fixed starting from gcc stable version 8.4.0 and
232   # onwards, but not for older ones. See gcc bug #86952.
233   ifndef CONFIG_CC_IS_CLANG
234     KBUILD_CFLAGS += -fno-jump-tables
235   endif
236 endif
237 
238 ifdef CONFIG_MITIGATION_SLS
239   KBUILD_CFLAGS += -mharden-sls=all
240 endif
241 
242 ifdef CONFIG_CALL_PADDING
243 PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
244 KBUILD_CFLAGS += $(PADDING_CFLAGS)
245 export PADDING_CFLAGS
246 
247 PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
248 KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS)
249 export PADDING_RUSTFLAGS
250 endif
251 
252 KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
253 
254 ifdef CONFIG_X86_NEED_RELOCS
255 LDFLAGS_vmlinux := --emit-relocs --discard-none
256 else
257 LDFLAGS_vmlinux :=
258 endif
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 #
265 ifdef CONFIG_X86_64
266 LDFLAGS_vmlinux += -z max-page-size=0x200000
267 endif
268 
269 
270 archscripts: scripts_basic
271 	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
272 
273 ###
274 # Syscall table generation
275 
276 archheaders:
277 	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
278 
279 ###
280 # Kernel objects
281 
282 libs-y  += arch/x86/lib/
283 
284 # drivers-y are linked after core-y
285 drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
286 drivers-$(CONFIG_PCI)            += arch/x86/pci/
287 
288 # suspend and hibernation support
289 drivers-$(CONFIG_PM) += arch/x86/power/
290 
291 drivers-$(CONFIG_VIDEO) += arch/x86/video/
292 
293 ####
294 # boot loader support. Several targets are kept for legacy purposes
295 
296 boot := arch/x86/boot
297 
298 BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
299 
300 PHONY += bzImage $(BOOT_TARGETS)
301 
302 # Default kernel to build
303 all: bzImage
304 
305 # KBUILD_IMAGE specify target image being built
306 KBUILD_IMAGE := $(boot)/bzImage
307 
308 bzImage: vmlinux
309 ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
310 	$(Q)$(MAKE) $(build)=arch/x86/tools posttest
311 endif
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 
319 PHONY += install
320 install:
321 	$(call cmd,install)
322 
323 vdso-install-$(CONFIG_X86_64)		+= arch/x86/entry/vdso/vdso64.so.dbg
324 vdso-install-$(CONFIG_X86_X32_ABI)	+= arch/x86/entry/vdso/vdsox32.so.dbg
325 vdso-install-$(CONFIG_COMPAT_32)	+= arch/x86/entry/vdso/vdso32.so.dbg
326 
327 archprepare: checkbin
328 checkbin:
329 ifdef CONFIG_MITIGATION_RETPOLINE
330 ifeq ($(RETPOLINE_CFLAGS),)
331 	@echo "You are building kernel with non-retpoline compiler." >&2
332 	@echo "Please update your compiler." >&2
333 	@false
334 endif
335 endif
336 
337 ifdef CONFIG_UNWINDER_ORC
338 orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
339 orc_hash_sh := $(srctree)/scripts/orc_hash.sh
340 targets += $(orc_hash_h)
341 quiet_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)
346 archprepare: $(orc_hash_h)
347 endif
348 
349 archclean:
350 	$(Q)rm -rf $(objtree)/arch/i386
351 	$(Q)rm -rf $(objtree)/arch/x86_64
352 
353 define archhelp
354   echo  '* bzImage		- Compressed kernel image (arch/x86/boot/bzImage)'
355   echo  '  install		- Install kernel using (your) ~/bin/$(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 
368 endef
369