1 # SPDX-License-Identifier: GPL-2.0
2 # Unified Makefile for i386 and x86_64
4 # select defconfig based on actual architecture
6 ifeq ($(shell uname -m | sed -e 's/i.86/i386/'),i386)
7 KBUILD_DEFCONFIG := i386_defconfig
9 KBUILD_DEFCONFIG := x86_64_defconfig
12 KBUILD_DEFCONFIG := $(ARCH)_defconfig
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)
19 ifdef CONFIG_CC_IS_CLANG
20 RETPOLINE_CFLAGS := -mretpoline-external-thunk
21 RETPOLINE_VDSO_CFLAGS := -mretpoline
23 RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch-cs-prefix)
25 ifdef CONFIG_MITIGATION_RETHUNK
26 RETHUNK_CFLAGS := -mfunction-return=thunk-extern
27 RETPOLINE_CFLAGS += $(RETHUNK_CFLAGS)
31 export RETPOLINE_CFLAGS
32 export RETPOLINE_VDSO_CFLAGS
34 # For gcc stack alignment is specified with -mpreferred-stack-boundary,
35 # clang has the option -mstack-alignment for that purpose.
36 ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
37 cc_stack_align4 := -mpreferred-stack-boundary=2
38 cc_stack_align8 := -mpreferred-stack-boundary=3
39 else ifneq ($(call cc-option, -mstack-alignment=16),)
40 cc_stack_align4 := -mstack-alignment=4
41 cc_stack_align8 := -mstack-alignment=8
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.
46 REALMODE_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)
51 REALMODE_CFLAGS += -ffreestanding
52 REALMODE_CFLAGS += -fno-stack-protector
53 REALMODE_CFLAGS += -Wno-address-of-packed-member
54 REALMODE_CFLAGS += $(cc_stack_align4)
55 REALMODE_CFLAGS += $(CLANG_FLAGS)
56 ifdef CONFIG_CC_IS_CLANG
57 REALMODE_CFLAGS += -Wno-gnu
59 export REALMODE_CFLAGS
61 # BITS is used as extension for files which are available in a 32 bit
62 # and a 64 bit version to simplify shared Makefiles.
63 # e.g.: obj-y += foo_$(BITS).o
67 # Prevent GCC from generating any FP code by mistake.
69 # This must happen before we try the -mpreferred-stack-boundary, see:
71 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
73 KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
74 KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json
75 KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
77 ifeq ($(CONFIG_X86_KERNEL_IBT),y)
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.
83 # (jump-tables are implicitly disabled by RETPOLINE)
85 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816
87 KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables)
88 KBUILD_RUSTFLAGS += -Zcf-protection=branch -Zno-jump-tables
90 KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
93 ifeq ($(CONFIG_X86_32),y)
96 CHECKFLAGS += -D__i386__
101 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
103 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built
104 # with nonstandard options
105 KBUILD_CFLAGS += -fno-pic
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)
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 += $(cflags-y)
116 # temporary until string.h is fixed
117 KBUILD_CFLAGS += -ffreestanding
119 ifeq ($(CONFIG_STACKPROTECTOR),y)
120 ifeq ($(CONFIG_SMP),y)
121 KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard
123 KBUILD_CFLAGS += -mstack-protector-guard=global
128 UTS_MACHINE := x86_64
129 CHECKFLAGS += -D__x86_64__
131 KBUILD_AFLAGS += -m64
132 KBUILD_CFLAGS += -m64
134 # Align jump targets to 1 byte, not the default 16 bytes:
135 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
137 # Pack loops tightly as well:
138 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
140 # Don't autogenerate traditional x87 instructions
141 KBUILD_CFLAGS += -mno-80387
142 KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
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)
153 # Use -mskip-rax-setup if supported.
154 KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
156 # FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
157 cflags-$(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 += $(cflags-y)
164 rustflags-$(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 += $(rustflags-y)
171 KBUILD_CFLAGS += -mno-red-zone
172 KBUILD_CFLAGS += -mcmodel=kernel
173 KBUILD_RUSTFLAGS += -Cno-redzone=y
174 KBUILD_RUSTFLAGS += -Ccode-model=kernel
178 # If the function graph tracer is used with mcount instead of fentry,
179 # '-maccumulate-outgoing-args' is needed to prevent a GCC bug
180 # (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
182 ifdef CONFIG_FUNCTION_GRAPH_TRACER
183 ifndef CONFIG_HAVE_FENTRY
184 ACCUMULATE_OUTGOING_ARGS := 1
188 ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
189 # This compiler flag is not supported by Clang:
190 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
193 # Workaround for a gcc prelease that unfortunately was shipped in a suse release
194 KBUILD_CFLAGS += -Wno-sign-compare
196 KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
198 # Avoid indirect branches in kernel to deal with Spectre
199 ifdef CONFIG_MITIGATION_RETPOLINE
200 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
201 # Additionally, avoid generating expensive indirect jumps which
202 # are subject to retpolines for small number of switch cases.
203 # clang turns off jump table generation by default when under
204 # retpoline builds, however, gcc does not for x86. This has
205 # only been fixed starting from gcc stable version 8.4.0 and
206 # onwards, but not for older ones. See gcc bug #86952.
207 ifndef CONFIG_CC_IS_CLANG
208 KBUILD_CFLAGS += -fno-jump-tables
212 ifdef CONFIG_MITIGATION_SLS
213 KBUILD_CFLAGS += -mharden-sls=all
216 ifdef CONFIG_CALL_PADDING
217 PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
218 KBUILD_CFLAGS += $(PADDING_CFLAGS)
219 export PADDING_CFLAGS
222 KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
224 ifdef CONFIG_X86_NEED_RELOCS
225 LDFLAGS_vmlinux := --emit-relocs --discard-none
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
236 LDFLAGS_vmlinux += -z max-page-size=0x200000
240 archscripts: scripts_basic
241 $(Q)$(MAKE) $(build)=arch/x86/tools relocs
244 # Syscall table generation
247 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
252 libs-y += arch/x86/lib/
254 core-y += arch/x86/virt/
256 # drivers-y are linked after core-y
257 drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
258 drivers-$(CONFIG_PCI) += arch/x86/pci/
260 # suspend and hibernation support
261 drivers-$(CONFIG_PM) += arch/x86/power/
263 drivers-$(CONFIG_FB_CORE) += arch/x86/video/
266 # boot loader support. Several targets are kept for legacy purposes
268 boot := arch/x86/boot
270 BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
272 PHONY += bzImage $(BOOT_TARGETS)
274 # Default kernel to build
277 # KBUILD_IMAGE specify target image being built
278 KBUILD_IMAGE := $(boot)/bzImage
281 ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
282 $(Q)$(MAKE) $(build)=arch/x86/tools posttest
284 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
285 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
286 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
288 $(BOOT_TARGETS): vmlinux
289 $(Q)$(MAKE) $(build)=$(boot) $@
295 vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg
296 vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg
297 vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32.so.dbg
299 archprepare: checkbin
301 ifdef CONFIG_MITIGATION_RETPOLINE
302 ifeq ($(RETPOLINE_CFLAGS),)
303 @echo "You are building kernel with non-retpoline compiler." >&2
304 @echo "Please update your compiler." >&2
309 ifdef CONFIG_UNWINDER_ORC
310 orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
311 orc_hash_sh := $(srctree)/scripts/orc_hash.sh
312 targets += $(orc_hash_h)
313 quiet_cmd_orc_hash = GEN $@
314 cmd_orc_hash = mkdir -p $(dir $@); \
315 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@
316 $(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE
317 $(call if_changed,orc_hash)
318 archprepare: $(orc_hash_h)
322 $(Q)rm -rf $(objtree)/arch/i386
323 $(Q)rm -rf $(objtree)/arch/x86_64
326 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)'
327 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
328 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to '
329 echo ' $$(INSTALL_PATH) and run lilo'
331 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
332 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
333 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
334 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
335 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
336 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:'
337 echo ' FDARGS="..." arguments for the booted kernel'
338 echo ' FDINITRD=file initrd for the booted kernel'