linux/arch/x86/Makefile
Kai Huang c33621b4c5 x86/virt/tdx: Wire up basic SEAMCALL functions
Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
host and certain physical attacks.  A CPU-attested software module
called 'the TDX module' runs inside a new isolated memory range as a
trusted hypervisor to manage and run protected VMs.

TDX introduces a new CPU mode: Secure Arbitration Mode (SEAM).  This
mode runs only the TDX module itself or other code to load the TDX
module.

The host kernel communicates with SEAM software via a new SEAMCALL
instruction.  This is conceptually similar to a guest->host hypercall,
except it is made from the host to SEAM software instead.  The TDX
module establishes a new SEAMCALL ABI which allows the host to
initialize the module and to manage VMs.

The SEAMCALL ABI is very similar to the TDCALL ABI and leverages much
TDCALL infrastructure.  Wire up basic functions to make SEAMCALLs for
the basic support of running TDX guests: __seamcall(), __seamcall_ret(),
and __seamcall_saved_ret() for TDH.VP.ENTER.  All SEAMCALLs involved in
the basic TDX support don't use "callee-saved" registers as input and
output, except the TDH.VP.ENTER.

To start to support TDX, create a new arch/x86/virt/vmx/tdx/tdx.c for
TDX host kernel support.  Add a new Kconfig option CONFIG_INTEL_TDX_HOST
to opt-in TDX host kernel support (to distinguish with TDX guest kernel
support).  So far only KVM uses TDX.  Make the new config option depend
on KVM_INTEL.

Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Isaku Yamahata <isaku.yamahata@intel.com>
Link: https://lore.kernel.org/all/4db7c3fc085e6af12acc2932294254ddb3d320b3.1692096753.git.kai.huang%40intel.com
2023-09-12 16:30:27 -07:00

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Makefile

# SPDX-License-Identifier: GPL-2.0
# Unified Makefile for i386 and x86_64
# select defconfig based on actual architecture
ifeq ($(ARCH),x86)
ifeq ($(shell uname -m | sed -e 's/i.86/i386/'),i386)
KBUILD_DEFCONFIG := i386_defconfig
else
KBUILD_DEFCONFIG := x86_64_defconfig
endif
else
KBUILD_DEFCONFIG := $(ARCH)_defconfig
endif
ifdef CONFIG_CC_IS_GCC
RETPOLINE_CFLAGS := $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
RETPOLINE_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register)
endif
ifdef CONFIG_CC_IS_CLANG
RETPOLINE_CFLAGS := -mretpoline-external-thunk
RETPOLINE_VDSO_CFLAGS := -mretpoline
endif
RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch-cs-prefix)
ifdef CONFIG_RETHUNK
RETHUNK_CFLAGS := -mfunction-return=thunk-extern
RETPOLINE_CFLAGS += $(RETHUNK_CFLAGS)
endif
export RETHUNK_CFLAGS
export RETPOLINE_CFLAGS
export RETPOLINE_VDSO_CFLAGS
# For gcc stack alignment is specified with -mpreferred-stack-boundary,
# clang has the option -mstack-alignment for that purpose.
ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
cc_stack_align4 := -mpreferred-stack-boundary=2
cc_stack_align8 := -mpreferred-stack-boundary=3
else ifneq ($(call cc-option, -mstack-alignment=16),)
cc_stack_align4 := -mstack-alignment=4
cc_stack_align8 := -mstack-alignment=8
endif
# How to compile the 16-bit code. Note we always compile for -march=i386;
# that way we can complain to the user if the CPU is insufficient.
REALMODE_CFLAGS := -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS \
-Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
-fno-strict-aliasing -fomit-frame-pointer -fno-pic \
-mno-mmx -mno-sse $(call cc-option,-fcf-protection=none)
REALMODE_CFLAGS += -ffreestanding
REALMODE_CFLAGS += -fno-stack-protector
REALMODE_CFLAGS += -Wno-address-of-packed-member
REALMODE_CFLAGS += $(cc_stack_align4)
REALMODE_CFLAGS += $(CLANG_FLAGS)
export REALMODE_CFLAGS
# BITS is used as extension for files which are available in a 32 bit
# and a 64 bit version to simplify shared Makefiles.
# e.g.: obj-y += foo_$(BITS).o
export BITS
#
# Prevent GCC from generating any FP code by mistake.
#
# This must happen before we try the -mpreferred-stack-boundary, see:
#
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
#
KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
ifeq ($(CONFIG_X86_KERNEL_IBT),y)
#
# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate
# NOTRACK prefixes. Current generation compilers unconditionally employ NOTRACK
# for jump-tables, as such, disable jump-tables for now.
#
# (jump-tables are implicitly disabled by RETPOLINE)
#
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104816
#
KBUILD_CFLAGS += $(call cc-option,-fcf-protection=branch -fno-jump-tables)
else
KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
endif
ifeq ($(CONFIG_X86_32),y)
BITS := 32
UTS_MACHINE := i386
CHECKFLAGS += -D__i386__
KBUILD_AFLAGS += -m32
KBUILD_CFLAGS += -m32
KBUILD_CFLAGS += -msoft-float -mregparm=3 -freg-struct-return
# Never want PIC in a 32-bit kernel, prevent breakage with GCC built
# with nonstandard options
KBUILD_CFLAGS += -fno-pic
# Align the stack to the register width instead of using the default
# alignment of 16 bytes. This reduces stack usage and the number of
# alignment instructions.
KBUILD_CFLAGS += $(cc_stack_align4)
# CPU-specific tuning. Anything which can be shared with UML should go here.
include $(srctree)/arch/x86/Makefile_32.cpu
KBUILD_CFLAGS += $(cflags-y)
# temporary until string.h is fixed
KBUILD_CFLAGS += -ffreestanding
ifeq ($(CONFIG_STACKPROTECTOR),y)
ifeq ($(CONFIG_SMP),y)
KBUILD_CFLAGS += -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard
else
KBUILD_CFLAGS += -mstack-protector-guard=global
endif
endif
else
BITS := 64
UTS_MACHINE := x86_64
CHECKFLAGS += -D__x86_64__
KBUILD_AFLAGS += -m64
KBUILD_CFLAGS += -m64
# Align jump targets to 1 byte, not the default 16 bytes:
KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1)
# Pack loops tightly as well:
KBUILD_CFLAGS += $(call cc-option,-falign-loops=1)
# Don't autogenerate traditional x87 instructions
KBUILD_CFLAGS += -mno-80387
KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
# By default gcc and clang use a stack alignment of 16 bytes for x86.
# However the standard kernel entry on x86-64 leaves the stack on an
# 8-byte boundary. If the compiler isn't informed about the actual
# alignment it will generate extra alignment instructions for the
# default alignment which keep the stack *mis*aligned.
# Furthermore an alignment to the register width reduces stack usage
# and the number of alignment instructions.
KBUILD_CFLAGS += $(cc_stack_align8)
# Use -mskip-rax-setup if supported.
KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
# FIXME - should be integrated in Makefile.cpu (Makefile_32.cpu)
cflags-$(CONFIG_MK8) += -march=k8
cflags-$(CONFIG_MPSC) += -march=nocona
cflags-$(CONFIG_MCORE2) += -march=core2
cflags-$(CONFIG_MATOM) += -march=atom
cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic
KBUILD_CFLAGS += $(cflags-y)
rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8
rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona
rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2
rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom
rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic
KBUILD_RUSTFLAGS += $(rustflags-y)
KBUILD_CFLAGS += -mno-red-zone
KBUILD_CFLAGS += -mcmodel=kernel
KBUILD_RUSTFLAGS += -Cno-redzone=y
KBUILD_RUSTFLAGS += -Ccode-model=kernel
endif
#
# If the function graph tracer is used with mcount instead of fentry,
# '-maccumulate-outgoing-args' is needed to prevent a GCC bug
# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109)
#
ifdef CONFIG_FUNCTION_GRAPH_TRACER
ifndef CONFIG_HAVE_FENTRY
ACCUMULATE_OUTGOING_ARGS := 1
endif
endif
ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
# This compiler flag is not supported by Clang:
KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
endif
# Workaround for a gcc prelease that unfortunately was shipped in a suse release
KBUILD_CFLAGS += -Wno-sign-compare
#
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
# Avoid indirect branches in kernel to deal with Spectre
ifdef CONFIG_RETPOLINE
KBUILD_CFLAGS += $(RETPOLINE_CFLAGS)
# Additionally, avoid generating expensive indirect jumps which
# are subject to retpolines for small number of switch cases.
# clang turns off jump table generation by default when under
# retpoline builds, however, gcc does not for x86. This has
# only been fixed starting from gcc stable version 8.4.0 and
# onwards, but not for older ones. See gcc bug #86952.
ifndef CONFIG_CC_IS_CLANG
KBUILD_CFLAGS += -fno-jump-tables
endif
endif
ifdef CONFIG_SLS
KBUILD_CFLAGS += -mharden-sls=all
endif
ifdef CONFIG_CALL_PADDING
PADDING_CFLAGS := -fpatchable-function-entry=$(CONFIG_FUNCTION_PADDING_BYTES),$(CONFIG_FUNCTION_PADDING_BYTES)
KBUILD_CFLAGS += $(PADDING_CFLAGS)
export PADDING_CFLAGS
endif
KBUILD_LDFLAGS += -m elf_$(UTS_MACHINE)
ifdef CONFIG_LTO_CLANG
ifeq ($(call test-lt, $(CONFIG_LLD_VERSION), 130000),y)
KBUILD_LDFLAGS += -plugin-opt=-stack-alignment=$(if $(CONFIG_X86_32),4,8)
endif
endif
ifdef CONFIG_X86_NEED_RELOCS
LDFLAGS_vmlinux := --emit-relocs --discard-none
else
LDFLAGS_vmlinux :=
endif
#
# The 64-bit kernel must be aligned to 2MB. Pass -z max-page-size=0x200000 to
# the linker to force 2MB page size regardless of the default page size used
# by the linker.
#
ifdef CONFIG_X86_64
LDFLAGS_vmlinux += -z max-page-size=0x200000
endif
archscripts: scripts_basic
$(Q)$(MAKE) $(build)=arch/x86/tools relocs
###
# Syscall table generation
archheaders:
$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
###
# Kernel objects
libs-y += arch/x86/lib/
core-y += arch/x86/virt/
# drivers-y are linked after core-y
drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
drivers-$(CONFIG_PCI) += arch/x86/pci/
# suspend and hibernation support
drivers-$(CONFIG_PM) += arch/x86/power/
drivers-$(CONFIG_FB_CORE) += arch/x86/video/
####
# boot loader support. Several targets are kept for legacy purposes
boot := arch/x86/boot
BOOT_TARGETS = bzdisk fdimage fdimage144 fdimage288 hdimage isoimage
PHONY += bzImage $(BOOT_TARGETS)
# Default kernel to build
all: bzImage
# KBUILD_IMAGE specify target image being built
KBUILD_IMAGE := $(boot)/bzImage
bzImage: vmlinux
ifeq ($(CONFIG_X86_DECODER_SELFTEST),y)
$(Q)$(MAKE) $(build)=arch/x86/tools posttest
endif
$(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE)
$(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot
$(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@
$(BOOT_TARGETS): vmlinux
$(Q)$(MAKE) $(build)=$(boot) $@
PHONY += install
install:
$(call cmd,install)
PHONY += vdso_install
vdso_install:
$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
archprepare: checkbin
checkbin:
ifdef CONFIG_RETPOLINE
ifeq ($(RETPOLINE_CFLAGS),)
@echo "You are building kernel with non-retpoline compiler." >&2
@echo "Please update your compiler." >&2
@false
endif
endif
ifdef CONFIG_UNWINDER_ORC
orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
orc_hash_sh := $(srctree)/scripts/orc_hash.sh
targets += $(orc_hash_h)
quiet_cmd_orc_hash = GEN $@
cmd_orc_hash = mkdir -p $(dir $@); \
$(CONFIG_SHELL) $(orc_hash_sh) < $< > $@
$(orc_hash_h): $(srctree)/arch/x86/include/asm/orc_types.h $(orc_hash_sh) FORCE
$(call if_changed,orc_hash)
archprepare: $(orc_hash_h)
endif
archclean:
$(Q)rm -rf $(objtree)/arch/i386
$(Q)rm -rf $(objtree)/arch/x86_64
define archhelp
echo '* bzImage - Compressed kernel image (arch/x86/boot/bzImage)'
echo ' install - Install kernel using (your) ~/bin/$(INSTALLKERNEL) or'
echo ' (distribution) /sbin/$(INSTALLKERNEL) or install to '
echo ' $$(INSTALL_PATH) and run lilo'
echo ''
echo ' fdimage - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
echo ' fdimage144 - Create 1.4MB boot floppy image (arch/x86/boot/fdimage)'
echo ' fdimage288 - Create 2.8MB boot floppy image (arch/x86/boot/fdimage)'
echo ' hdimage - Create a BIOS/EFI hard disk image (arch/x86/boot/hdimage)'
echo ' isoimage - Create a boot CD-ROM image (arch/x86/boot/image.iso)'
echo ' bzdisk/fdimage*/hdimage/isoimage also accept:'
echo ' FDARGS="..." arguments for the booted kernel'
echo ' FDINITRD=file initrd for the booted kernel'
endef