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 := -mindirect-branch=thunk-extern -mindirect-branch-register 17RETPOLINE_VDSO_CFLAGS := -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. 40ifdef CONFIG_CC_IS_GCC 41 cc_stack_align4 := -mpreferred-stack-boundary=2 42 cc_stack_align8 := -mpreferred-stack-boundary=3 43endif 44ifdef CONFIG_CC_IS_CLANG 45 cc_stack_align4 := -mstack-alignment=4 46 cc_stack_align8 := -mstack-alignment=8 47endif 48 49# How to compile the 16-bit code. Note we always compile for -march=i386; 50# that way we can complain to the user if the CPU is insufficient. 51REALMODE_CFLAGS := $(CC_FLAGS_DIALECT) -m16 -g -Os \ 52 -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \ 53 -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ 54 -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ 55 -mno-mmx -mno-sse $(call cc-option,-fcf-protection=none) 56 57REALMODE_CFLAGS += -ffreestanding 58REALMODE_CFLAGS += -fno-stack-protector 59REALMODE_CFLAGS += -Wno-address-of-packed-member 60REALMODE_CFLAGS += $(cc_stack_align4) 61REALMODE_CFLAGS += $(CLANG_FLAGS) 62export REALMODE_CFLAGS 63 64# BITS is used as extension for files which are available in a 32 bit 65# and a 64 bit version to simplify shared Makefiles. 66# e.g.: obj-y += foo_$(BITS).o 67export BITS 68 69# 70# Prevent GCC from generating any FP code by mistake. 71# 72# This must happen before we try the -mpreferred-stack-boundary, see: 73# 74# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 75# 76KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -mno-sse4a 77KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json 78KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2 79 80# 81# CFLAGS for compiling floating point code inside the kernel. 82# 83CC_FLAGS_FPU := -msse -msse2 84ifdef CONFIG_CC_IS_GCC 85CC_FLAGS_FPU += -mhard-float 86endif 87 88ifeq ($(CONFIG_X86_KERNEL_IBT),y) 89# 90# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate 91# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK 92# for jump-tables, as such, disable jump-tables for now. 93# 94# (jump-tables are implicitly disabled by RETPOLINE) 95# 96# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816 97# 98KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables) 99KBUILD_RUSTFLAGS += -Zcf-protection=branch $(if $(call rustc-min-version,109300),-Cjump-tables=n,-Zno-jump-tables) 100else 101KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) 102endif 103 104ifeq ($(CONFIG_X86_32),y) 105 BITS := 32 106 UTS_MACHINE := i386 107 CHECKFLAGS += -D__i386__ 108 109 KBUILD_AFLAGS += -m32 110 KBUILD_CFLAGS += -m32 111 112 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return 113 114 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built 115 # with nonstandard options 116 KBUILD_CFLAGS += -fno-pic 117 118 # Align the stack to the register width instead of using the default 119 # alignment of 16 bytes. This reduces stack usage and the number of 120 # alignment instructions. 121 KBUILD_CFLAGS += $(cc_stack_align4) 122 123 # CPU-specific tuning. Anything which can be shared with UML should go here. 124 include $(srctree)/arch/x86/Makefile_32.cpu 125 KBUILD_CFLAGS += $(cflags-y) 126 127 percpu_seg := fs 128else 129 BITS := 64 130 UTS_MACHINE := x86_64 131 CHECKFLAGS += -D__x86_64__ 132 133 KBUILD_AFLAGS += -m64 134 KBUILD_CFLAGS += -m64 135 136 # Align jump targets to 1 byte, not the default 16 bytes: 137 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 138 139 # Pack loops tightly as well: 140 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 141 142 # Don't autogenerate traditional x87 instructions 143 KBUILD_CFLAGS += -mno-80387 144 KBUILD_CFLAGS += -mno-fp-ret-in-387 145 146 # By default gcc and clang use a stack alignment of 16 bytes for x86. 147 # However the standard kernel entry on x86-64 leaves the stack on an 148 # 8-byte boundary. If the compiler isn't informed about the actual 149 # alignment it will generate extra alignment instructions for the 150 # default alignment which keep the stack *mis*aligned. 151 # Furthermore an alignment to the register width reduces stack usage 152 # and the number of alignment instructions. 153 KBUILD_CFLAGS += $(cc_stack_align8) 154 155 # Use -mskip-rax-setup if supported. 156 KBUILD_CFLAGS += -mskip-rax-setup 157 158ifdef CONFIG_X86_NATIVE_CPU 159 KBUILD_CFLAGS += -march=native 160 KBUILD_RUSTFLAGS += -Ctarget-cpu=native 161else 162 KBUILD_CFLAGS += -march=x86-64 -mtune=generic 163 KBUILD_RUSTFLAGS += -Ctarget-cpu=x86-64 -Ztune-cpu=generic 164endif 165 166 KBUILD_CFLAGS += -mno-red-zone 167 KBUILD_CFLAGS += -mcmodel=kernel 168 KBUILD_RUSTFLAGS += -Cno-redzone=y 169 KBUILD_RUSTFLAGS += -Ccode-model=kernel 170 171 percpu_seg := gs 172endif 173 174ifeq ($(CONFIG_STACKPROTECTOR),y) 175 ifeq ($(CONFIG_SMP),y) 176 KBUILD_CFLAGS += -mstack-protector-guard-reg=$(percpu_seg) 177 KBUILD_CFLAGS += -mstack-protector-guard-symbol=__ref_stack_chk_guard 178 else 179 KBUILD_CFLAGS += -mstack-protector-guard=global 180 endif 181endif 182 183# 184# If the function graph tracer is used with mcount instead of fentry, 185# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 186# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 187# 188ifdef CONFIG_FUNCTION_GRAPH_TRACER 189 ifndef CONFIG_HAVE_FENTRY 190 ACCUMULATE_OUTGOING_ARGS := 1 191 endif 192endif 193 194ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 195 # This compiler flag is not supported by Clang: 196 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 197endif 198 199# Workaround for a gcc prelease that unfortunately was shipped in a suse release 200KBUILD_CFLAGS += -Wno-sign-compare 201# 202KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 203 204# Avoid indirect branches in kernel to deal with Spectre 205ifdef CONFIG_MITIGATION_RETPOLINE 206 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 207 KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS) 208 # Additionally, avoid generating expensive indirect jumps which 209 # are subject to retpolines for small number of switch cases. 210 # LLVM turns off jump table generation by default when under 211 # retpoline builds, however, gcc does not for x86. This has 212 # only been fixed starting from gcc stable version 8.4.0 and 213 # onwards, but not for older ones. See gcc bug #86952. 214 ifndef CONFIG_CC_IS_CLANG 215 KBUILD_CFLAGS += -fno-jump-tables 216 endif 217endif 218 219ifdef CONFIG_MITIGATION_SLS 220 KBUILD_CFLAGS += -mharden-sls=all 221endif 222 223ifdef CONFIG_CALL_PADDING 224PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 225KBUILD_CFLAGS += $(PADDING_CFLAGS) 226export PADDING_CFLAGS 227 228PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 229KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS) 230export PADDING_RUSTFLAGS 231endif 232 233KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 234 235# 236# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 237# the linker to force 2MB page size regardless of the default page size used 238# by the linker. 239# 240ifdef CONFIG_X86_64 241LDFLAGS_vmlinux += -z max-page-size=0x200000 242endif 243 244 245archscripts: scripts_basic 246 $(Q)$(MAKE) $(build)=arch/x86/tools relocs vdso2c 247 248### 249# Syscall table generation 250 251archheaders: 252 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 253 254### 255# <asm/cpufeaturemasks.h> header generation 256 257cpufeaturemasks.hdr := arch/x86/include/generated/asm/cpufeaturemasks.h 258cpufeaturemasks.awk := $(srctree)/arch/x86/tools/cpufeaturemasks.awk 259cpufeatures_hdr := $(srctree)/arch/x86/include/asm/cpufeatures.h 260targets += $(cpufeaturemasks.hdr) 261 filechk_gen_featuremasks = $(AWK) -f $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) 262 263$(cpufeaturemasks.hdr): $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) FORCE 264 $(shell mkdir -p $(dir $@)) 265 $(call filechk,gen_featuremasks) 266archprepare: $(cpufeaturemasks.hdr) 267 268### 269# Kernel objects 270 271libs-y += arch/x86/lib/ 272 273# drivers-y are linked after core-y 274drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/ 275drivers-$(CONFIG_PCI) += arch/x86/pci/ 276 277# suspend and hibernation support 278drivers-$(CONFIG_PM) += arch/x86/power/ 279 280drivers-$(CONFIG_VIDEO) += arch/x86/video/ 281 282#### 283# boot loader support. Several targets are kept for legacy purposes 284 285boot := arch/x86/boot 286 287BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 288 289PHONY += bzImage $(BOOT_TARGETS) 290 291# Default kernel to build 292all: bzImage 293 294# KBUILD_IMAGE specify target image being built 295KBUILD_IMAGE := $(boot)/bzImage 296 297bzImage: vmlinux 298ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 299 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 300endif 301 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 302 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 303 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 304 305$(BOOT_TARGETS): vmlinux 306 $(Q)$(MAKE) $(build)=$(boot) $@ 307 308PHONY += install 309install: 310 $(call cmd,install) 311 312vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64/vdso64.so.dbg 313vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdso64/vdsox32.so.dbg 314vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32/vdso32.so.dbg 315 316archprepare: checkbin 317checkbin: 318ifdef CONFIG_MITIGATION_RETPOLINE 319ifeq ($(RETPOLINE_CFLAGS),) 320 @echo "You are building kernel with non-retpoline compiler." >&2 321 @echo "Please update your compiler." >&2 322 @false 323endif 324endif 325 326ifdef CONFIG_UNWINDER_ORC 327orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h 328orc_hash_sh := $(srctree)/scripts/orc_hash.sh 329targets += $(orc_hash_h) 330quiet_cmd_orc_hash = GEN $@ 331 cmd_orc_hash = mkdir -p $(dir $@); \ 332 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ 333$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE 334 $(call if_changed,orc_hash) 335archprepare: $(orc_hash_h) 336endif 337 338archclean: 339 $(Q)rm -rf $(objtree)/arch/i386 340 $(Q)rm -rf $(objtree)/arch/x86_64 341 342define archhelp 343 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 344 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 345 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 346 echo ' $$(INSTALL_PATH) and run lilo' 347 echo '' 348 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 349 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 350 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 351 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 352 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 353 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 354 echo ' FDARGS="..." arguments for the booted kernel' 355 echo ' FDINITRD=file initrd for the booted kernel' 356 357endef 358