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=$(objtree)/scripts/target.json 78KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2 79 80# The target.json file is not available when invoking rustc-option, so use the 81# built-in target when checking whether flags are supported instead. 82KBUILD_RUSTFLAGS_OPTION_CHKS += --target=x86_64-unknown-none 83 84# 85# CFLAGS for compiling floating point code inside the kernel. 86# 87CC_FLAGS_FPU := -msse -msse2 88ifdef CONFIG_CC_IS_GCC 89CC_FLAGS_FPU += -mhard-float 90endif 91 92ifeq ($(CONFIG_X86_KERNEL_IBT),y) 93# 94# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate 95# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK 96# for jump-tables, as such, disable jump-tables for now. 97# 98# (jump-tables are implicitly disabled by RETPOLINE) 99# 100# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816 101# 102KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables) 103KBUILD_RUSTFLAGS += -Zcf-protection=branch $(if $(call rustc-min-version,109300),-Cjump-tables=n,-Zno-jump-tables) 104else 105KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) 106endif 107 108ifeq ($(CONFIG_X86_32),y) 109 BITS := 32 110 UTS_MACHINE := i386 111 CHECKFLAGS += -D__i386__ 112 113 KBUILD_AFLAGS += -m32 114 KBUILD_CFLAGS += -m32 115 116 KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return 117 118 # Never want PIC in a 32-bit kernel, prevent breakage with GCC built 119 # with nonstandard options 120 KBUILD_CFLAGS += -fno-pic 121 122 # Align the stack to the register width instead of using the default 123 # alignment of 16 bytes. This reduces stack usage and the number of 124 # alignment instructions. 125 KBUILD_CFLAGS += $(cc_stack_align4) 126 127 # CPU-specific tuning. Anything which can be shared with UML should go here. 128 include $(srctree)/arch/x86/Makefile_32.cpu 129 KBUILD_CFLAGS += $(cflags-y) 130 131 percpu_seg := fs 132else 133 BITS := 64 134 UTS_MACHINE := x86_64 135 CHECKFLAGS += -D__x86_64__ 136 137 KBUILD_AFLAGS += -m64 138 KBUILD_CFLAGS += -m64 139 140 # Align jump targets to 1 byte, not the default 16 bytes: 141 KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) 142 143 # Pack loops tightly as well: 144 KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) 145 146 # Don't autogenerate traditional x87 instructions 147 KBUILD_CFLAGS += -mno-80387 148 KBUILD_CFLAGS += -mno-fp-ret-in-387 149 150 # By default gcc and clang use a stack alignment of 16 bytes for x86. 151 # However the standard kernel entry on x86-64 leaves the stack on an 152 # 8-byte boundary. If the compiler isn't informed about the actual 153 # alignment it will generate extra alignment instructions for the 154 # default alignment which keep the stack *mis*aligned. 155 # Furthermore an alignment to the register width reduces stack usage 156 # and the number of alignment instructions. 157 KBUILD_CFLAGS += $(cc_stack_align8) 158 159 # Use -mskip-rax-setup if supported. 160 KBUILD_CFLAGS += -mskip-rax-setup 161 162ifdef CONFIG_X86_NATIVE_CPU 163 KBUILD_CFLAGS += -march=native 164 KBUILD_RUSTFLAGS += -Ctarget-cpu=native 165else 166 KBUILD_CFLAGS += -march=x86-64 -mtune=generic 167 KBUILD_RUSTFLAGS += -Ctarget-cpu=x86-64 -Ztune-cpu=generic 168endif 169 170 KBUILD_CFLAGS += -mno-red-zone 171 KBUILD_CFLAGS += -mcmodel=kernel 172 KBUILD_RUSTFLAGS += -Cno-redzone=y 173 KBUILD_RUSTFLAGS += -Ccode-model=kernel 174 175 percpu_seg := gs 176endif 177 178ifeq ($(CONFIG_STACKPROTECTOR),y) 179 ifeq ($(CONFIG_SMP),y) 180 KBUILD_CFLAGS += -mstack-protector-guard-reg=$(percpu_seg) 181 KBUILD_CFLAGS += -mstack-protector-guard-symbol=__ref_stack_chk_guard 182 else 183 KBUILD_CFLAGS += -mstack-protector-guard=global 184 endif 185endif 186 187# 188# If the function graph tracer is used with mcount instead of fentry, 189# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 190# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 191# 192ifdef CONFIG_FUNCTION_GRAPH_TRACER 193 ifndef CONFIG_HAVE_FENTRY 194 ACCUMULATE_OUTGOING_ARGS := 1 195 endif 196endif 197 198ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 199 # This compiler flag is not supported by Clang: 200 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 201endif 202 203# Workaround for a gcc prelease that unfortunately was shipped in a suse release 204KBUILD_CFLAGS += -Wno-sign-compare 205# 206KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 207 208# Avoid indirect branches in kernel to deal with Spectre 209ifdef CONFIG_MITIGATION_RETPOLINE 210 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 211 KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS) 212 # Additionally, avoid generating expensive indirect jumps which 213 # are subject to retpolines for small number of switch cases. 214 # LLVM turns off jump table generation by default when under 215 # retpoline builds, however, gcc does not for x86. This has 216 # only been fixed starting from gcc stable version 8.4.0 and 217 # onwards, but not for older ones. See gcc bug #86952. 218 ifndef CONFIG_CC_IS_CLANG 219 KBUILD_CFLAGS += -fno-jump-tables 220 endif 221endif 222 223ifdef CONFIG_MITIGATION_SLS 224 KBUILD_CFLAGS += -mharden-sls=all 225endif 226 227ifdef CONFIG_CALL_PADDING 228PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 229KBUILD_CFLAGS += $(PADDING_CFLAGS) 230export PADDING_CFLAGS 231 232PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 233KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS) 234export PADDING_RUSTFLAGS 235endif 236 237KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 238 239# 240# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 241# the linker to force 2MB page size regardless of the default page size used 242# by the linker. 243# 244ifdef CONFIG_X86_64 245LDFLAGS_vmlinux += -z max-page-size=0x200000 246endif 247 248 249archscripts: scripts_basic 250 $(Q)$(MAKE) $(build)=arch/x86/tools relocs vdso2c 251 252### 253# Syscall table generation 254 255archheaders: 256 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 257 258### 259# <asm/cpufeaturemasks.h> header generation 260 261cpufeaturemasks.hdr := arch/x86/include/generated/asm/cpufeaturemasks.h 262cpufeaturemasks.awk := $(srctree)/arch/x86/tools/cpufeaturemasks.awk 263cpufeatures_hdr := $(srctree)/arch/x86/include/asm/cpufeatures.h 264targets += $(cpufeaturemasks.hdr) 265 filechk_gen_featuremasks = $(AWK) -f $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) 266 267$(cpufeaturemasks.hdr): $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) FORCE 268 $(shell mkdir -p $(dir $@)) 269 $(call filechk,gen_featuremasks) 270archprepare: $(cpufeaturemasks.hdr) 271 272### 273# Kernel objects 274 275libs-y += arch/x86/lib/ 276 277# drivers-y are linked after core-y 278drivers-$(CONFIG_PCI) += arch/x86/pci/ 279 280# suspend and hibernation support 281drivers-$(CONFIG_PM) += arch/x86/power/ 282 283drivers-$(CONFIG_VIDEO) += arch/x86/video/ 284 285#### 286# boot loader support. Several targets are kept for legacy purposes 287 288boot := arch/x86/boot 289 290BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 291 292PHONY += bzImage $(BOOT_TARGETS) 293 294# Default kernel to build 295all: bzImage 296 297# KBUILD_IMAGE specify target image being built 298KBUILD_IMAGE := $(boot)/bzImage 299 300bzImage: vmlinux 301ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 302 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 303endif 304 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 305 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 306 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 307 308$(BOOT_TARGETS): vmlinux 309 $(Q)$(MAKE) $(build)=$(boot) $@ 310 311PHONY += install 312install: 313 $(call cmd,install) 314 315vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64/vdso64.so.dbg 316vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdso64/vdsox32.so.dbg 317vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32/vdso32.so.dbg 318 319archprepare: checkbin 320checkbin: 321ifdef CONFIG_MITIGATION_RETPOLINE 322ifeq ($(RETPOLINE_CFLAGS),) 323 @echo "You are building kernel with non-retpoline compiler." >&2 324 @echo "Please update your compiler." >&2 325 @false 326endif 327endif 328 329ifdef CONFIG_UNWINDER_ORC 330orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h 331orc_hash_sh := $(srctree)/scripts/orc_hash.sh 332targets += $(orc_hash_h) 333quiet_cmd_orc_hash = GEN $@ 334 cmd_orc_hash = mkdir -p $(dir $@); \ 335 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ 336$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE 337 $(call if_changed,orc_hash) 338archprepare: $(orc_hash_h) 339endif 340 341archclean: 342 $(Q)rm -rf $(objtree)/arch/i386 343 $(Q)rm -rf $(objtree)/arch/x86_64 344 345define archhelp 346 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 347 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 348 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 349 echo ' $$(INSTALL_PATH) and run lilo' 350 echo '' 351 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 352 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 353 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 354 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 355 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 356 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 357 echo ' FDARGS="..." arguments for the booted kernel' 358 echo ' FDINITRD=file initrd for the booted kernel' 359 360endef 361