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 += $(cflags-y)
139
140    ifneq ($(call clang-min-version, 160000),y)
141        # https://github.com/llvm/llvm-project/issues/53645
142        KBUILD_CFLAGS += -ffreestanding
143    endif
144
145        percpu_seg := fs
146else
147        BITS := 64
148        UTS_MACHINE := x86_64
149        CHECKFLAGS += -D__x86_64__
150
151        KBUILD_AFLAGS += -m64
152        KBUILD_CFLAGS += -m64
153
154        # Align jump targets to 1 byte, not the default 16 bytes:
155        KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
156
157        # Pack loops tightly as well:
158        KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
159
160        # Don't autogenerate traditional x87 instructions
161        KBUILD_CFLAGS += -mno-80387
162        KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
163
164        # By default gcc and clang use a stack alignment of 16 bytes for x86.
165        # However the standard kernel entry on x86-64 leaves the stack on an
166        # 8-byte boundary. If the compiler isn't informed about the actual
167        # alignment it will generate extra alignment instructions for the
168        # default alignment which keep the stack *mis*aligned.
169        # Furthermore an alignment to the register width reduces stack usage
170        # and the number of alignment instructions.
171        KBUILD_CFLAGS += $(cc_stack_align8)
172
173	# Use -mskip-rax-setup if supported.
174	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
175
176        KBUILD_CFLAGS += -march=x86-64 -mtune=generic
177        KBUILD_RUSTFLAGS += -Ctarget-cpu=x86-64 -Ztune-cpu=generic
178
179        KBUILD_CFLAGS += -mno-red-zone
180        KBUILD_CFLAGS += -mcmodel=kernel
181        KBUILD_RUSTFLAGS += -Cno-redzone=y
182        KBUILD_RUSTFLAGS += -Ccode-model=kernel
183
184        percpu_seg := gs
185endif
186
187ifeq ($(CONFIG_STACKPROTECTOR),y)
188    ifeq ($(CONFIG_SMP),y)
189	KBUILD_CFLAGS += -mstack-protector-guard-reg=$(percpu_seg)
190	KBUILD_CFLAGS += -mstack-protector-guard-symbol=__ref_stack_chk_guard
191    else
192	KBUILD_CFLAGS += -mstack-protector-guard=global
193    endif
194endif
195
196#
197# If the function graph tracer is used with mcount instead of fentry,
198# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
199# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
200#
201ifdef CONFIG_FUNCTION_GRAPH_TRACER
202  ifndef CONFIG_HAVE_FENTRY
203	ACCUMULATE_OUTGOING_ARGS := 1
204  endif
205endif
206
207ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
208	# This compiler flag is not supported by Clang:
209	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
210endif
211
212# Workaround for a gcc prelease that unfortunately was shipped in a suse release
213KBUILD_CFLAGS += -Wno-sign-compare
214#
215KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
216
217# Avoid indirect branches in kernel to deal with Spectre
218ifdef CONFIG_MITIGATION_RETPOLINE
219  KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
220  KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS)
221  # Additionally, avoid generating expensive indirect jumps which
222  # are subject to retpolines for small number of switch cases.
223  # LLVM turns off jump table generation by default when under
224  # retpoline builds, however, gcc does not for x86. This has
225  # only been fixed starting from gcc stable version 8.4.0 and
226  # onwards, but not for older ones. See gcc bug #86952.
227  ifndef CONFIG_CC_IS_CLANG
228    KBUILD_CFLAGS += -fno-jump-tables
229  endif
230endif
231
232ifdef CONFIG_MITIGATION_SLS
233  KBUILD_CFLAGS += -mharden-sls=all
234endif
235
236ifdef CONFIG_CALL_PADDING
237PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
238KBUILD_CFLAGS += $(PADDING_CFLAGS)
239export PADDING_CFLAGS
240
241PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
242KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS)
243export PADDING_RUSTFLAGS
244endif
245
246KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
247
248#
249# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
250# the linker to force 2MB page size regardless of the default page size used
251# by the linker.
252#
253ifdef CONFIG_X86_64
254LDFLAGS_vmlinux += -z max-page-size=0x200000
255endif
256
257
258archscripts: scripts_basic
259	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
260
261###
262# Syscall table generation
263
264archheaders:
265	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
266
267###
268# <asm/cpufeaturemasks.h> header generation
269
270cpufeaturemasks.hdr := arch/x86/include/generated/asm/cpufeaturemasks.h
271cpufeaturemasks.awk := $(srctree)/arch/x86/tools/cpufeaturemasks.awk
272cpufeatures_hdr := $(srctree)/arch/x86/include/asm/cpufeatures.h
273targets += $(cpufeaturemasks.hdr)
274      filechk_gen_featuremasks = $(AWK) -f $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG)
275
276$(cpufeaturemasks.hdr): $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) FORCE
277	$(shell mkdir -p $(dir $@))
278	$(call filechk,gen_featuremasks)
279archprepare: $(cpufeaturemasks.hdr)
280
281###
282# Kernel objects
283
284libs-y  += arch/x86/lib/
285
286# drivers-y are linked after core-y
287drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
288drivers-$(CONFIG_PCI)            += arch/x86/pci/
289
290# suspend and hibernation support
291drivers-$(CONFIG_PM) += arch/x86/power/
292
293drivers-$(CONFIG_VIDEO) += arch/x86/video/
294
295####
296# boot loader support. Several targets are kept for legacy purposes
297
298boot := arch/x86/boot
299
300BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
301
302PHONY += bzImage $(BOOT_TARGETS)
303
304# Default kernel to build
305all: bzImage
306
307# KBUILD_IMAGE specify target image being built
308KBUILD_IMAGE := $(boot)/bzImage
309
310bzImage: vmlinux
311ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
312	$(Q)$(MAKE) $(build)=arch/x86/tools posttest
313endif
314	$(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
315	$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
316	$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
317
318$(BOOT_TARGETS): vmlinux
319	$(Q)$(MAKE) $(build)=$(boot) $@
320
321PHONY += install
322install:
323	$(call cmd,install)
324
325vdso-install-$(CONFIG_X86_64)		+= arch/x86/entry/vdso/vdso64.so.dbg
326vdso-install-$(CONFIG_X86_X32_ABI)	+= arch/x86/entry/vdso/vdsox32.so.dbg
327vdso-install-$(CONFIG_COMPAT_32)	+= arch/x86/entry/vdso/vdso32.so.dbg
328
329archprepare: checkbin
330checkbin:
331ifdef CONFIG_MITIGATION_RETPOLINE
332ifeq ($(RETPOLINE_CFLAGS),)
333	@echo "You are building kernel with non-retpoline compiler." >&2
334	@echo "Please update your compiler." >&2
335	@false
336endif
337endif
338
339ifdef CONFIG_UNWINDER_ORC
340orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
341orc_hash_sh := $(srctree)/scripts/orc_hash.sh
342targets += $(orc_hash_h)
343quiet_cmd_orc_hash = GEN     $@
344      cmd_orc_hash = mkdir -p $(dir $@); \
345		     $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@
346$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE
347	$(call if_changed,orc_hash)
348archprepare: $(orc_hash_h)
349endif
350
351archclean:
352	$(Q)rm -rf $(objtree)/arch/i386
353	$(Q)rm -rf $(objtree)/arch/x86_64
354
355define archhelp
356  echo  '* bzImage		- Compressed kernel image (arch/x86/boot/bzImage)'
357  echo  '  install		- Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
358  echo  '			  (distribution) /sbin/$(INSTALLKERNEL) or install to '
359  echo  '			  $$(INSTALL_PATH) and run lilo'
360  echo  ''
361  echo  '  fdimage		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
362  echo  '  fdimage144		- Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
363  echo  '  fdimage288		- Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
364  echo  '  hdimage		- Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
365  echo  '  isoimage		- Create a boot CD-ROM image (arch/x86/boot/image.iso)'
366  echo  '			  bzdisk/fdimage*/hdimage/isoimage also accept:'
367  echo  '			  FDARGS="..."  arguments for the booted kernel'
368  echo  '			  FDINITRD=file initrd for the booted kernel'
369
370endef
371