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 # Prevent the compiler from generating EGPR use. The kernel is 165 # not yet prepared for general in-kernel use. 166 KBUILD_CFLAGS += $(call cc-option,-mno-apx-features=egpr) 167 168 # generate_rust_target.rs handles Rust APX gating. 169 KBUILD_RUSTFLAGS += -Ctarget-cpu=native 170else 171 KBUILD_CFLAGS += -march=x86-64 -mtune=generic 172 KBUILD_RUSTFLAGS += -Ctarget-cpu=x86-64 -Ztune-cpu=generic 173endif 174 175 KBUILD_CFLAGS += -mno-red-zone 176 KBUILD_CFLAGS += -mcmodel=kernel 177 KBUILD_RUSTFLAGS += -Cno-redzone=y 178 KBUILD_RUSTFLAGS += -Ccode-model=kernel 179 180 percpu_seg := gs 181endif 182 183ifeq ($(CONFIG_STACKPROTECTOR),y) 184 ifeq ($(CONFIG_SMP),y) 185 KBUILD_CFLAGS += -mstack-protector-guard-reg=$(percpu_seg) 186 KBUILD_CFLAGS += -mstack-protector-guard-symbol=__ref_stack_chk_guard 187 else 188 KBUILD_CFLAGS += -mstack-protector-guard=global 189 endif 190endif 191 192# 193# If the function graph tracer is used with mcount instead of fentry, 194# '-maccumulate-outgoing-args' is needed to prevent a GCC bug 195# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109) 196# 197ifdef CONFIG_FUNCTION_GRAPH_TRACER 198 ifndef CONFIG_HAVE_FENTRY 199 ACCUMULATE_OUTGOING_ARGS := 1 200 endif 201endif 202 203ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1) 204 # This compiler flag is not supported by Clang: 205 KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,) 206endif 207 208# Workaround for a gcc prelease that unfortunately was shipped in a suse release 209KBUILD_CFLAGS += -Wno-sign-compare 210# 211KBUILD_CFLAGS += -fno-asynchronous-unwind-tables 212 213# Avoid indirect branches in kernel to deal with Spectre 214ifdef CONFIG_MITIGATION_RETPOLINE 215 KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) 216 KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS) 217 # Additionally, avoid generating expensive indirect jumps which 218 # are subject to retpolines for small number of switch cases. 219 # LLVM turns off jump table generation by default when under 220 # retpoline builds, however, gcc does not for x86. This has 221 # only been fixed starting from gcc stable version 8.4.0 and 222 # onwards, but not for older ones. See gcc bug #86952. 223 ifndef CONFIG_CC_IS_CLANG 224 KBUILD_CFLAGS += -fno-jump-tables 225 endif 226endif 227 228ifdef CONFIG_MITIGATION_SLS 229 KBUILD_CFLAGS += -mharden-sls=all 230endif 231 232ifdef CONFIG_CALL_PADDING 233PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 234KBUILD_CFLAGS += $(PADDING_CFLAGS) 235export PADDING_CFLAGS 236 237PADDING_RUSTFLAGS := -Zpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES) 238KBUILD_RUSTFLAGS += $(PADDING_RUSTFLAGS) 239export PADDING_RUSTFLAGS 240endif 241 242KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE) 243 244# 245# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to 246# the linker to force 2MB page size regardless of the default page size used 247# by the linker. 248# 249ifdef CONFIG_X86_64 250LDFLAGS_vmlinux += -z max-page-size=0x200000 251endif 252 253 254archscripts: scripts_basic 255 $(Q)$(MAKE) $(build)=arch/x86/tools relocs vdso2c 256 257### 258# Syscall table generation 259 260archheaders: 261 $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all 262 263### 264# <asm/cpufeaturemasks.h> header generation 265 266cpufeaturemasks.hdr := arch/x86/include/generated/asm/cpufeaturemasks.h 267cpufeaturemasks.awk := $(srctree)/arch/x86/tools/cpufeaturemasks.awk 268cpufeatures_hdr := $(srctree)/arch/x86/include/asm/cpufeatures.h 269targets += $(cpufeaturemasks.hdr) 270 filechk_gen_featuremasks = $(AWK) -f $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) 271 272$(cpufeaturemasks.hdr): $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) FORCE 273 $(shell mkdir -p $(dir $@)) 274 $(call filechk,gen_featuremasks) 275archprepare: $(cpufeaturemasks.hdr) 276 277### 278# Kernel objects 279 280libs-y += arch/x86/lib/ 281 282# drivers-y are linked after core-y 283drivers-$(CONFIG_PCI) += arch/x86/pci/ 284 285# suspend and hibernation support 286drivers-$(CONFIG_PM) += arch/x86/power/ 287 288drivers-$(CONFIG_VIDEO) += arch/x86/video/ 289 290#### 291# boot loader support. Several targets are kept for legacy purposes 292 293boot := arch/x86/boot 294 295BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage 296 297PHONY += bzImage $(BOOT_TARGETS) 298 299# Default kernel to build 300all: bzImage 301 302# KBUILD_IMAGE specify target image being built 303KBUILD_IMAGE := $(boot)/bzImage 304 305bzImage: vmlinux 306ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) 307 $(Q)$(MAKE) $(build)=arch/x86/tools posttest 308endif 309 $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) 310 $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot 311 $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ 312 313$(BOOT_TARGETS): vmlinux 314 $(Q)$(MAKE) $(build)=$(boot) $@ 315 316PHONY += install 317install: 318 $(call cmd,install) 319 320vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64/vdso64.so.dbg 321vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdso64/vdsox32.so.dbg 322vdso-install-$(CONFIG_COMPAT_32) += arch/x86/entry/vdso/vdso32/vdso32.so.dbg 323 324archprepare: checkbin 325checkbin: 326ifdef CONFIG_MITIGATION_RETPOLINE 327ifeq ($(RETPOLINE_CFLAGS),) 328 @echo "You are building kernel with non-retpoline compiler." >&2 329 @echo "Please update your compiler." >&2 330 @false 331endif 332endif 333 334ifdef CONFIG_UNWINDER_ORC 335orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h 336orc_hash_sh := $(srctree)/scripts/orc_hash.sh 337targets += $(orc_hash_h) 338quiet_cmd_orc_hash = GEN $@ 339 cmd_orc_hash = mkdir -p $(dir $@); \ 340 $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@ 341$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE 342 $(call if_changed,orc_hash) 343archprepare: $(orc_hash_h) 344endif 345 346archclean: 347 $(Q)rm -rf $(objtree)/arch/i386 348 $(Q)rm -rf $(objtree)/arch/x86_64 349 350define archhelp 351 echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)' 352 echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or' 353 echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to ' 354 echo ' $$(INSTALL_PATH) and run lilo' 355 echo '' 356 echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 357 echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)' 358 echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)' 359 echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)' 360 echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)' 361 echo ' bzdisk/fdimage*/hdimage/isoimage also accept:' 362 echo ' FDARGS="..." arguments for the booted kernel' 363 echo ' FDINITRD=file initrd for the booted kernel' 364 365endef 366