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
339