Kconfig 93.2 KB
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# SPDX-License-Identifier: GPL-2.0
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# Select 32 or 64 bit
config 64BIT
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	bool "64-bit kernel" if "$(ARCH)" = "x86"
	default "$(ARCH)" != "i386"
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	help
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	  Say yes to build a 64-bit kernel - formerly known as x86_64
	  Say no to build a 32-bit kernel - formerly known as i386

config X86_32
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	def_bool y
	depends on !64BIT
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	# Options that are inherently 32-bit kernel only:
	select ARCH_WANT_IPC_PARSE_VERSION
	select CLKSRC_I8253
	select CLONE_BACKWARDS
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	select GENERIC_VDSO_32
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	select HAVE_DEBUG_STACKOVERFLOW
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	select KMAP_LOCAL
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	select MODULES_USE_ELF_REL
	select OLD_SIGACTION
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	select ARCH_SPLIT_ARG64
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config X86_64
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	def_bool y
	depends on 64BIT
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	# Options that are inherently 64-bit kernel only:
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	select ARCH_HAS_GIGANTIC_PAGE
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	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
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	select ARCH_USE_CMPXCHG_LOCKREF
	select HAVE_ARCH_SOFT_DIRTY
	select MODULES_USE_ELF_RELA
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	select NEED_DMA_MAP_STATE
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	select SWIOTLB
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	select ARCH_HAS_ELFCORE_COMPAT
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	select ZONE_DMA32
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config FORCE_DYNAMIC_FTRACE
	def_bool y
	depends on X86_32
	depends on FUNCTION_TRACER
	select DYNAMIC_FTRACE
	help
	 We keep the static function tracing (!DYNAMIC_FTRACE) around
	 in order to test the non static function tracing in the
	 generic code, as other architectures still use it. But we
	 only need to keep it around for x86_64. No need to keep it
	 for x86_32. For x86_32, force DYNAMIC_FTRACE. 
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#
# Arch settings
#
# ( Note that options that are marked 'if X86_64' could in principle be
#   ported to 32-bit as well. )
#
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config X86
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	def_bool y
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	#
	# Note: keep this list sorted alphabetically
	#
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	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
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	select ARCH_32BIT_OFF_T			if X86_32
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	select ARCH_CLOCKSOURCE_INIT
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	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
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	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 || (X86_32 && HIGHMEM)
	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
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	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
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	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
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	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
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	select ARCH_HAS_CACHE_LINE_SIZE
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	select ARCH_HAS_DEBUG_VIRTUAL
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	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
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	select ARCH_HAS_DEVMEM_IS_ALLOWED
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	select ARCH_HAS_EARLY_DEBUG		if KGDB
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	select ARCH_HAS_ELF_RANDOMIZE
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	select ARCH_HAS_FAST_MULTIPLIER
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	select ARCH_HAS_FILTER_PGPROT
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	select ARCH_HAS_FORTIFY_SOURCE
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	select ARCH_HAS_GCOV_PROFILE_ALL
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	select ARCH_HAS_KCOV			if X86_64 && STACK_VALIDATION
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	select ARCH_HAS_MEM_ENCRYPT
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	select ARCH_HAS_MEMBARRIER_SYNC_CORE
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	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
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	select ARCH_HAS_PMEM_API		if X86_64
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	select ARCH_HAS_PTE_DEVMAP		if X86_64
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	select ARCH_HAS_PTE_SPECIAL
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	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
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	select ARCH_HAS_COPY_MC			if X86_64
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	select ARCH_HAS_SET_MEMORY
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	select ARCH_HAS_SET_DIRECT_MAP
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	select ARCH_HAS_STRICT_KERNEL_RWX
	select ARCH_HAS_STRICT_MODULE_RWX
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	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
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	select ARCH_HAS_SYSCALL_WRAPPER
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	select ARCH_HAS_UBSAN_SANITIZE_ALL
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	select ARCH_HAS_DEBUG_WX
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	select ARCH_HAS_ZONE_DMA_SET if EXPERT
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	select ARCH_HAVE_NMI_SAFE_CMPXCHG
	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
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	select ARCH_MIGHT_HAVE_PC_PARPORT
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	select ARCH_MIGHT_HAVE_PC_SERIO
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	select ARCH_STACKWALK
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	select ARCH_SUPPORTS_ACPI
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	select ARCH_SUPPORTS_ATOMIC_RMW
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	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
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	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
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	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
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	select ARCH_SUPPORTS_LTO_CLANG
	select ARCH_SUPPORTS_LTO_CLANG_THIN
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	select ARCH_USE_BUILTIN_BSWAP
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	select ARCH_USE_MEMTEST
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	select ARCH_USE_QUEUED_RWLOCKS
	select ARCH_USE_QUEUED_SPINLOCKS
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	select ARCH_USE_SYM_ANNOTATIONS
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	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
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	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
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	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
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	select ARCH_WANTS_NO_INSTR
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	select ARCH_WANT_HUGE_PMD_SHARE
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	select ARCH_WANT_LD_ORPHAN_WARN
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	select ARCH_WANTS_THP_SWAP		if X86_64
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	select BUILDTIME_TABLE_SORT
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	select CLKEVT_I8253
	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
	select CLOCKSOURCE_WATCHDOG
	select DCACHE_WORD_ACCESS
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	select EDAC_ATOMIC_SCRUB
	select EDAC_SUPPORT
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	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
	select GENERIC_CLOCKEVENTS_MIN_ADJUST
	select GENERIC_CMOS_UPDATE
	select GENERIC_CPU_AUTOPROBE
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	select GENERIC_CPU_VULNERABILITIES
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	select GENERIC_EARLY_IOREMAP
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	select GENERIC_ENTRY
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	select GENERIC_FIND_FIRST_BIT
	select GENERIC_IOMAP
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	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
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	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
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	select GENERIC_IRQ_MIGRATION		if SMP
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	select GENERIC_IRQ_PROBE
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	select GENERIC_IRQ_RESERVATION_MODE
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	select GENERIC_IRQ_SHOW
	select GENERIC_PENDING_IRQ		if SMP
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	select GENERIC_PTDUMP
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	select GENERIC_SMP_IDLE_THREAD
	select GENERIC_STRNCPY_FROM_USER
	select GENERIC_STRNLEN_USER
	select GENERIC_TIME_VSYSCALL
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	select GENERIC_GETTIMEOFDAY
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	select GENERIC_VDSO_TIME_NS
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	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
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	select HARDIRQS_SW_RESEND
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	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
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	select HAVE_ACPI_APEI			if ACPI
	select HAVE_ACPI_APEI_NMI		if ACPI
	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
	select HAVE_ARCH_AUDITSYSCALL
	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
	select HAVE_ARCH_JUMP_LABEL
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	select HAVE_ARCH_JUMP_LABEL_RELATIVE
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	select HAVE_ARCH_KASAN			if X86_64
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	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
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	select HAVE_ARCH_KFENCE
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	select HAVE_ARCH_KGDB
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	select HAVE_ARCH_MMAP_RND_BITS		if MMU
	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
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	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
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	select HAVE_ARCH_PREL32_RELOCATIONS
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	select HAVE_ARCH_SECCOMP_FILTER
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	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
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	select HAVE_ARCH_STACKLEAK
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	select HAVE_ARCH_TRACEHOOK
	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
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	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
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	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
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	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
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	select HAVE_ARCH_VMAP_STACK		if X86_64
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	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
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	select HAVE_ARCH_WITHIN_STACK_FRAMES
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	select HAVE_ASM_MODVERSIONS
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	select HAVE_CMPXCHG_DOUBLE
	select HAVE_CMPXCHG_LOCAL
	select HAVE_CONTEXT_TRACKING		if X86_64
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	select HAVE_CONTEXT_TRACKING_OFFSTACK	if HAVE_CONTEXT_TRACKING
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	select HAVE_C_RECORDMCOUNT
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	select HAVE_OBJTOOL_MCOUNT		if STACK_VALIDATION
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	select HAVE_DEBUG_KMEMLEAK
	select HAVE_DMA_CONTIGUOUS
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	select HAVE_DYNAMIC_FTRACE
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	select HAVE_DYNAMIC_FTRACE_WITH_REGS
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	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
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	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
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	select HAVE_EBPF_JIT
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	select HAVE_EFFICIENT_UNALIGNED_ACCESS
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	select HAVE_EISA
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	select HAVE_EXIT_THREAD
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	select HAVE_FAST_GUP
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	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
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	select HAVE_FTRACE_MCOUNT_RECORD
	select HAVE_FUNCTION_GRAPH_TRACER
	select HAVE_FUNCTION_TRACER
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	select HAVE_GCC_PLUGINS
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	select HAVE_HW_BREAKPOINT
	select HAVE_IDE
	select HAVE_IOREMAP_PROT
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	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
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	select HAVE_IRQ_TIME_ACCOUNTING
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	select HAVE_KERNEL_BZIP2
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	select HAVE_KERNEL_GZIP
	select HAVE_KERNEL_LZ4
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	select HAVE_KERNEL_LZMA
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	select HAVE_KERNEL_LZO
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	select HAVE_KERNEL_XZ
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	select HAVE_KERNEL_ZSTD
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	select HAVE_KPROBES
	select HAVE_KPROBES_ON_FTRACE
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	select HAVE_FUNCTION_ERROR_INJECTION
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	select HAVE_KRETPROBES
	select HAVE_KVM
	select HAVE_LIVEPATCH			if X86_64
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	select HAVE_MIXED_BREAKPOINTS_REGS
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	select HAVE_MOD_ARCH_SPECIFIC
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	select HAVE_MOVE_PMD
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	select HAVE_MOVE_PUD
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	select HAVE_NMI
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	select HAVE_OPTPROBES
	select HAVE_PCSPKR_PLATFORM
	select HAVE_PERF_EVENTS
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	select HAVE_PERF_EVENTS_NMI
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	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
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	select HAVE_PCI
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	select HAVE_PERF_REGS
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	select HAVE_PERF_USER_STACK_DUMP
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	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
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	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
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	select HAVE_REGS_AND_STACK_ACCESS_API
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	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
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	select HAVE_FUNCTION_ARG_ACCESS_API
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	select HAVE_SOFTIRQ_ON_OWN_STACK
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	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
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	select HAVE_STACK_VALIDATION		if X86_64
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	select HAVE_STATIC_CALL
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	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
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	select HAVE_PREEMPT_DYNAMIC
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	select HAVE_RSEQ
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	select HAVE_SYSCALL_TRACEPOINTS
	select HAVE_UNSTABLE_SCHED_CLOCK
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	select HAVE_USER_RETURN_NOTIFIER
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	select HAVE_GENERIC_VDSO
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	select HOTPLUG_SMT			if SMP
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	select IRQ_FORCED_THREADING
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	select NEED_SG_DMA_LENGTH
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	select PCI_DOMAINS			if PCI
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	select PCI_LOCKLESS_CONFIG		if PCI
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	select PERF_EVENTS
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	select RTC_LIB
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	select RTC_MC146818_LIB
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	select SPARSE_IRQ
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	select SRCU
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	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
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	select SYSCTL_EXCEPTION_TRACE
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	select THREAD_INFO_IN_TASK
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	select USER_STACKTRACE_SUPPORT
	select VIRT_TO_BUS
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	select HAVE_ARCH_KCSAN			if X86_64
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	select X86_FEATURE_NAMES		if PROC_FS
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	select PROC_PID_ARCH_STATUS		if PROC_FS
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	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
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config INSTRUCTION_DECODER
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	def_bool y
	depends on KPROBES || PERF_EVENTS || UPROBES
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config OUTPUT_FORMAT
	string
	default "elf32-i386" if X86_32
	default "elf64-x86-64" if X86_64

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config LOCKDEP_SUPPORT
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	def_bool y
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config STACKTRACE_SUPPORT
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	def_bool y
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config MMU
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	def_bool y
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config ARCH_MMAP_RND_BITS_MIN
	default 28 if 64BIT
	default 8

config ARCH_MMAP_RND_BITS_MAX
	default 32 if 64BIT
	default 16

config ARCH_MMAP_RND_COMPAT_BITS_MIN
	default 8

config ARCH_MMAP_RND_COMPAT_BITS_MAX
	default 16

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config SBUS
	bool

config GENERIC_ISA_DMA
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	def_bool y
	depends on ISA_DMA_API
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config GENERIC_BUG
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	def_bool y
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	depends on BUG
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	select GENERIC_BUG_RELATIVE_POINTERS if X86_64

config GENERIC_BUG_RELATIVE_POINTERS
	bool
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config ARCH_MAY_HAVE_PC_FDC
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	def_bool y
	depends on ISA_DMA_API
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config GENERIC_CALIBRATE_DELAY
	def_bool y

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config ARCH_HAS_CPU_RELAX
	def_bool y

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config ARCH_HAS_FILTER_PGPROT
	def_bool y

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config HAVE_SETUP_PER_CPU_AREA
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	def_bool y
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config NEED_PER_CPU_EMBED_FIRST_CHUNK
	def_bool y

config NEED_PER_CPU_PAGE_FIRST_CHUNK
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	def_bool y

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config ARCH_HIBERNATION_POSSIBLE
	def_bool y

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config ARCH_SUSPEND_POSSIBLE
	def_bool y

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config ARCH_WANT_GENERAL_HUGETLB
	def_bool y

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config AUDIT_ARCH
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	def_bool y if X86_64
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config KASAN_SHADOW_OFFSET
	hex
	depends on KASAN
	default 0xdffffc0000000000

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config HAVE_INTEL_TXT
	def_bool y
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	depends on INTEL_IOMMU && ACPI
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config X86_32_SMP
	def_bool y
	depends on X86_32 && SMP

config X86_64_SMP
	def_bool y
	depends on X86_64 && SMP

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config ARCH_SUPPORTS_UPROBES
	def_bool y

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config FIX_EARLYCON_MEM
	def_bool y

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config DYNAMIC_PHYSICAL_MASK
	bool

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config PGTABLE_LEVELS
	int
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	default 5 if X86_5LEVEL
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	default 4 if X86_64
	default 3 if X86_PAE
	default 2

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config CC_HAS_SANE_STACKPROTECTOR
	bool
	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
	help
	   We have to make sure stack protector is unconditionally disabled if
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	   the compiler produces broken code or if it does not let us control
	   the segment on 32-bit kernels.
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menu "Processor type and features"

config SMP
	bool "Symmetric multi-processing support"
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	help
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	  This enables support for systems with more than one CPU. If you have
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	  a system with only one CPU, say N. If you have a system with more
	  than one CPU, say Y.
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	  If you say N here, the kernel will run on uni- and multiprocessor
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	  machines, but will use only one CPU of a multiprocessor machine. If
	  you say Y here, the kernel will run on many, but not all,
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	  uniprocessor machines. On a uniprocessor machine, the kernel
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	  will run faster if you say N here.

	  Note that if you say Y here and choose architecture "586" or
	  "Pentium" under "Processor family", the kernel will not work on 486
	  architectures. Similarly, multiprocessor kernels for the "PPro"
	  architecture may not work on all Pentium based boards.

	  People using multiprocessor machines who say Y here should also say
	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
	  Management" code will be disabled if you say Y here.

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	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
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	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
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	  <http://www.tldp.org/docs.html#howto>.

	  If you don't know what to do here, say N.

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config X86_FEATURE_NAMES
	bool "Processor feature human-readable names" if EMBEDDED
	default y
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	help
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	  This option compiles in a table of x86 feature bits and corresponding
	  names.  This is required to support /proc/cpuinfo and a few kernel
	  messages.  You can disable this to save space, at the expense of
	  making those few kernel messages show numeric feature bits instead.

	  If in doubt, say Y.

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config X86_X2APIC
	bool "Support x2apic"
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	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
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	help
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	  This enables x2apic support on CPUs that have this feature.

	  This allows 32-bit apic IDs (so it can support very large systems),
	  and accesses the local apic via MSRs not via mmio.

	  If you don't know what to do here, say N.

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config X86_MPPARSE
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	bool "Enable MPS table" if ACPI
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	default y
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	depends on X86_LOCAL_APIC
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	help
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	  For old smp systems that do not have proper acpi support. Newer systems
	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it

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config GOLDFISH
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	def_bool y
	depends on X86_GOLDFISH
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config RETPOLINE
	bool "Avoid speculative indirect branches in kernel"
	default y
	help
	  Compile kernel with the retpoline compiler options to guard against
	  kernel-to-user data leaks by avoiding speculative indirect
	  branches. Requires a compiler with -mindirect-branch=thunk-extern
	  support for full protection. The kernel may run slower.

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config X86_CPU_RESCTRL
	bool "x86 CPU resource control support"
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	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
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	select KERNFS
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	select PROC_CPU_RESCTRL		if PROC_FS
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	help
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	  Enable x86 CPU resource control support.
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	  Provide support for the allocation and monitoring of system resources
	  usage by the CPU.

	  Intel calls this Intel Resource Director Technology
	  (Intel(R) RDT). More information about RDT can be found in the
	  Intel x86 Architecture Software Developer Manual.

	  AMD calls this AMD Platform Quality of Service (AMD QoS).
	  More information about AMD QoS can be found in the AMD64 Technology
	  Platform Quality of Service Extensions manual.
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	  Say N if unsure.

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if X86_32
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config X86_BIGSMP
	bool "Support for big SMP systems with more than 8 CPUs"
	depends on SMP
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	help
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	  This option is needed for the systems that have more than 8 CPUs.
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config X86_EXTENDED_PLATFORM
	bool "Support for extended (non-PC) x86 platforms"
	default y
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	help
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	  If you disable this option then the kernel will only support
	  standard PC platforms. (which covers the vast majority of
	  systems out there.)

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	  If you enable this option then you'll be able to select support
	  for the following (non-PC) 32 bit x86 platforms:
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		Goldfish (Android emulator)
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		AMD Elan
		RDC R-321x SoC
		SGI 320/540 (Visual Workstation)
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		STA2X11-based (e.g. Northville)
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		Moorestown MID devices
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	  If you have one of these systems, or if you want to build a
	  generic distribution kernel, say Y here - otherwise say N.
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endif
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if X86_64
config X86_EXTENDED_PLATFORM
	bool "Support for extended (non-PC) x86 platforms"
	default y
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	help
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	  If you disable this option then the kernel will only support
	  standard PC platforms. (which covers the vast majority of
	  systems out there.)

	  If you enable this option then you'll be able to select support
	  for the following (non-PC) 64 bit x86 platforms:
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Steffen Persvold 已提交
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		Numascale NumaChip
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		ScaleMP vSMP
		SGI Ultraviolet

	  If you have one of these systems, or if you want to build a
	  generic distribution kernel, say Y here - otherwise say N.
endif
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# This is an alphabetically sorted list of 64 bit extended platforms
# Please maintain the alphabetic order if and when there are additions
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config X86_NUMACHIP
	bool "Numascale NumaChip"
	depends on X86_64
	depends on X86_EXTENDED_PLATFORM
	depends on NUMA
	depends on SMP
	depends on X86_X2APIC
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	depends on PCI_MMCONFIG
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	help
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Steffen Persvold 已提交
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	  Adds support for Numascale NumaChip large-SMP systems. Needed to
	  enable more than ~168 cores.
	  If you don't have one of these, you should say N here.
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549 550
config X86_VSMP
	bool "ScaleMP vSMP"
551
	select HYPERVISOR_GUEST
552 553 554
	select PARAVIRT
	depends on X86_64 && PCI
	depends on X86_EXTENDED_PLATFORM
555
	depends on SMP
556
	help
557 558 559
	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
	  supposed to run on these EM64T-based machines.  Only choose this option
	  if you have one of these machines.
560

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config X86_UV
	bool "SGI Ultraviolet"
	depends on X86_64
564
	depends on X86_EXTENDED_PLATFORM
565
	depends on NUMA
566
	depends on EFI
567
	depends on KEXEC_CORE
568
	depends on X86_X2APIC
569
	depends on PCI
570
	help
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	  This option is needed in order to support SGI Ultraviolet systems.
	  If you don't have one of these, you should say N here.

574 575
# Following is an alphabetically sorted list of 32 bit extended platforms
# Please maintain the alphabetic order if and when there are additions
576

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config X86_GOLDFISH
578 579
	bool "Goldfish (Virtual Platform)"
	depends on X86_EXTENDED_PLATFORM
580
	help
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	 Enable support for the Goldfish virtual platform used primarily
	 for Android development. Unless you are building for the Android
	 Goldfish emulator say N here.

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config X86_INTEL_CE
	bool "CE4100 TV platform"
	depends on PCI
	depends on PCI_GODIRECT
589
	depends on X86_IO_APIC
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	depends on X86_32
	depends on X86_EXTENDED_PLATFORM
592
	select X86_REBOOTFIXUPS
593 594
	select OF
	select OF_EARLY_FLATTREE
595
	help
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	  Select for the Intel CE media processor (CE4100) SOC.
	  This option compiles in support for the CE4100 SOC for settop
	  boxes and media devices.

600
config X86_INTEL_MID
601 602
	bool "Intel MID platform support"
	depends on X86_EXTENDED_PLATFORM
603
	depends on X86_PLATFORM_DEVICES
604
	depends on PCI
605
	depends on X86_64 || (PCI_GOANY && X86_32)
606
	depends on X86_IO_APIC
607
	select I2C
608
	select DW_APB_TIMER
609
	select APB_TIMER
610
	select INTEL_SCU_PCI
611
	select MFD_INTEL_MSIC
612
	help
613 614 615
	  Select to build a kernel capable of supporting Intel MID (Mobile
	  Internet Device) platform systems which do not have the PCI legacy
	  interfaces. If you are building for a PC class system say N here.
616

617 618
	  Intel MID platforms are based on an Intel processor and chipset which
	  consume less power than most of the x86 derivatives.
619

620 621 622 623 624 625 626 627 628 629 630
config X86_INTEL_QUARK
	bool "Intel Quark platform support"
	depends on X86_32
	depends on X86_EXTENDED_PLATFORM
	depends on X86_PLATFORM_DEVICES
	depends on X86_TSC
	depends on PCI
	depends on PCI_GOANY
	depends on X86_IO_APIC
	select IOSF_MBI
	select INTEL_IMR
631
	select COMMON_CLK
632
	help
633 634 635 636
	  Select to include support for Quark X1000 SoC.
	  Say Y here if you have a Quark based system such as the Arduino
	  compatible Intel Galileo.

637 638
config X86_INTEL_LPSS
	bool "Intel Low Power Subsystem Support"
639
	depends on X86 && ACPI && PCI
640
	select COMMON_CLK
641
	select PINCTRL
642
	select IOSF_MBI
643
	help
644 645
	  Select to build support for Intel Low Power Subsystem such as
	  found on Intel Lynxpoint PCH. Selecting this option enables
646 647
	  things like clock tree (common clock framework) and pincontrol
	  which are needed by the LPSS peripheral drivers.
648

649 650 651 652 653
config X86_AMD_PLATFORM_DEVICE
	bool "AMD ACPI2Platform devices support"
	depends on ACPI
	select COMMON_CLK
	select PINCTRL
654
	help
655 656 657 658 659
	  Select to interpret AMD specific ACPI device to platform device
	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
	  implemented under PINCTRL subsystem.

660 661 662
config IOSF_MBI
	tristate "Intel SoC IOSF Sideband support for SoC platforms"
	depends on PCI
663
	help
664 665 666 667 668 669 670 671 672 673 674 675 676
	  This option enables sideband register access support for Intel SoC
	  platforms. On these platforms the IOSF sideband is used in lieu of
	  MSR's for some register accesses, mostly but not limited to thermal
	  and power. Drivers may query the availability of this device to
	  determine if they need the sideband in order to work on these
	  platforms. The sideband is available on the following SoC products.
	  This list is not meant to be exclusive.
	   - BayTrail
	   - Braswell
	   - Quark

	  You should say Y if you are running a kernel on one of these SoC's.

677 678 679
config IOSF_MBI_DEBUG
	bool "Enable IOSF sideband access through debugfs"
	depends on IOSF_MBI && DEBUG_FS
680
	help
681 682 683 684 685 686 687 688 689
	  Select this option to expose the IOSF sideband access registers (MCR,
	  MDR, MCRX) through debugfs to write and read register information from
	  different units on the SoC. This is most useful for obtaining device
	  state information for debug and analysis. As this is a general access
	  mechanism, users of this option would have specific knowledge of the
	  device they want to access.

	  If you don't require the option or are in doubt, say N.

690 691
config X86_RDC321X
	bool "RDC R-321x SoC"
692
	depends on X86_32
693 694 695
	depends on X86_EXTENDED_PLATFORM
	select M486
	select X86_REBOOTFIXUPS
696
	help
697 698 699 700
	  This option is needed for RDC R-321x system-on-chip, also known
	  as R-8610-(G).
	  If you don't have one of these chips, you should say N here.

701
config X86_32_NON_STANDARD
702 703
	bool "Support non-standard 32-bit SMP architectures"
	depends on X86_32 && SMP
704
	depends on X86_EXTENDED_PLATFORM
705
	help
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	  This option compiles in the bigsmp and STA2X11 default
	  subarchitectures.  It is intended for a generic binary
	  kernel. If you select them all, kernel will probe it one by
	  one and will fallback to default.
710

711
# Alphabetically sorted list of Non standard 32 bit platforms
712

713
config X86_SUPPORTS_MEMORY_FAILURE
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	def_bool y
715 716 717 718 719 720 721
	# MCE code calls memory_failure():
	depends on X86_MCE
	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
	depends on X86_64 || !SPARSEMEM
	select ARCH_SUPPORTS_MEMORY_FAILURE

722 723 724 725 726
config STA2X11
	bool "STA2X11 Companion Chip Support"
	depends on X86_32_NON_STANDARD && PCI
	select SWIOTLB
	select MFD_STA2X11
727
	select GPIOLIB
728
	help
729 730 731 732 733 734
	  This adds support for boards based on the STA2X11 IO-Hub,
	  a.k.a. "ConneXt". The chip is used in place of the standard
	  PC chipset, so all "standard" peripherals are missing. If this
	  option is selected the kernel will still be able to boot on
	  standard PC machines.

735 736 737
config X86_32_IRIS
	tristate "Eurobraille/Iris poweroff module"
	depends on X86_32
738
	help
739 740 741 742 743 744 745 746 747
	  The Iris machines from EuroBraille do not have APM or ACPI support
	  to shut themselves down properly.  A special I/O sequence is
	  needed to do so, which is what this module does at
	  kernel shutdown.

	  This is only for Iris machines from EuroBraille.

	  If unused, say N.

748
config SCHED_OMIT_FRAME_POINTER
749 750
	def_bool y
	prompt "Single-depth WCHAN output"
751
	depends on X86
752
	help
753 754 755 756 757 758 759
	  Calculate simpler /proc/<PID>/wchan values. If this option
	  is disabled then wchan values will recurse back to the
	  caller function. This provides more accurate wchan values,
	  at the expense of slightly more scheduling overhead.

	  If in doubt, say "Y".

760 761
menuconfig HYPERVISOR_GUEST
	bool "Linux guest support"
762
	help
763 764 765
	  Say Y here to enable options for running Linux under various hyper-
	  visors. This option enables basic hypervisor detection and platform
	  setup.
766

767 768
	  If you say N, all options in this submenu will be skipped and
	  disabled, and Linux guest support won't be built in.
769

770
if HYPERVISOR_GUEST
771

772 773
config PARAVIRT
	bool "Enable paravirtualization code"
774
	depends on HAVE_STATIC_CALL
775
	help
776 777 778 779 780
	  This changes the kernel so it can modify itself when it is run
	  under a hypervisor, potentially improving performance significantly
	  over full virtualization.  However, when run without a hypervisor
	  the kernel is theoretically slower and slightly larger.

781 782 783
config PARAVIRT_XXL
	bool

784 785 786
config PARAVIRT_DEBUG
	bool "paravirt-ops debugging"
	depends on PARAVIRT && DEBUG_KERNEL
787
	help
788 789 790
	  Enable to debug paravirt_ops internals.  Specifically, BUG if
	  a paravirt_op is missing when it is called.

791 792
config PARAVIRT_SPINLOCKS
	bool "Paravirtualization layer for spinlocks"
793
	depends on PARAVIRT && SMP
794
	help
795 796 797 798
	  Paravirtualized spinlocks allow a pvops backend to replace the
	  spinlock implementation with something virtualization-friendly
	  (for example, block the virtual CPU rather than spinning).

799 800
	  It has a minimal impact on native kernels and gives a nice performance
	  benefit on paravirtualized KVM / Xen kernels.
801

802
	  If you are unsure how to answer this question, answer Y.
803

804 805 806
config X86_HV_CALLBACK_VECTOR
	def_bool n

807
source "arch/x86/xen/Kconfig"
808

809 810 811 812
config KVM_GUEST
	bool "KVM Guest support (including kvmclock)"
	depends on PARAVIRT
	select PARAVIRT_CLOCK
813
	select ARCH_CPUIDLE_HALTPOLL
814
	select X86_HV_CALLBACK_VECTOR
815
	default y
816
	help
817 818 819 820 821
	  This option enables various optimizations for running under the KVM
	  hypervisor. It includes a paravirtualized clock, so that instead
	  of relying on a PIT (or probably other) emulation by the
	  underlying device model, the host provides the guest with
	  timing infrastructure such as time of day, and system time
822

823
config ARCH_CPUIDLE_HALTPOLL
824 825 826
	def_bool n
	prompt "Disable host haltpoll when loading haltpoll driver"
	help
827 828
	  If virtualized under KVM, disable host haltpoll.

829 830
config PVH
	bool "Support for running PVH guests"
831
	help
832 833 834
	  This option enables the PVH entry point for guest virtual machines
	  as specified in the x86/HVM direct boot ABI.

835 836 837
config PARAVIRT_TIME_ACCOUNTING
	bool "Paravirtual steal time accounting"
	depends on PARAVIRT
838
	help
839 840 841 842 843 844 845 846 847
	  Select this option to enable fine granularity task steal time
	  accounting. Time spent executing other tasks in parallel with
	  the current vCPU is discounted from the vCPU power. To account for
	  that, there can be a small performance impact.

	  If in doubt, say N here.

config PARAVIRT_CLOCK
	bool
848

849 850
config JAILHOUSE_GUEST
	bool "Jailhouse non-root cell support"
851
	depends on X86_64 && PCI
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Jan Kiszka 已提交
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	select X86_PM_TIMER
853
	help
854 855 856 857
	  This option allows to run Linux as guest in a Jailhouse non-root
	  cell. You can leave this option disabled if you only want to start
	  Jailhouse and run Linux afterwards in the root cell.

858 859 860
config ACRN_GUEST
	bool "ACRN Guest support"
	depends on X86_64
861
	select X86_HV_CALLBACK_VECTOR
862 863 864 865 866 867 868
	help
	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
	  a flexible, lightweight reference open-source hypervisor, built with
	  real-time and safety-criticality in mind. It is built for embedded
	  IOT with small footprint and real-time features. More details can be
	  found in https://projectacrn.org/.

869
endif #HYPERVISOR_GUEST
870

871 872 873
source "arch/x86/Kconfig.cpu"

config HPET_TIMER
874
	def_bool X86_64
875
	prompt "HPET Timer Support" if X86_32
876
	help
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877 878 879 880 881 882
	  Use the IA-PC HPET (High Precision Event Timer) to manage
	  time in preference to the PIT and RTC, if a HPET is
	  present.
	  HPET is the next generation timer replacing legacy 8254s.
	  The HPET provides a stable time base on SMP
	  systems, unlike the TSC, but it is more expensive to access,
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	  as it is off-chip.  The interface used is documented
	  in the HPET spec, revision 1.
885

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Ingo Molnar 已提交
886 887 888
	  You can safely choose Y here.  However, HPET will only be
	  activated if the platform and the BIOS support this feature.
	  Otherwise the 8254 will be used for timing services.
889

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890
	  Choose N to continue using the legacy 8254 timer.
891 892

config HPET_EMULATE_RTC
893
	def_bool y
894
	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
895

896
# Mark as expert because too many people got it wrong.
897
# The code disables itself when not needed.
898 899
config DMI
	default y
900
	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
901
	bool "Enable DMI scanning" if EXPERT
902
	help
903 904 905 906 907
	  Enabled scanning of DMI to identify machine quirks. Say Y
	  here unless you have verified that your setup is not
	  affected by entries in the DMI blacklist. Required by PNP
	  BIOS code.

908
config GART_IOMMU
909
	bool "Old AMD GART IOMMU support"
910
	select DMA_OPS
911
	select IOMMU_HELPER
912
	select SWIOTLB
913
	depends on X86_64 && PCI && AMD_NB
914
	help
915 916 917 918 919 920 921 922 923 924 925 926 927 928 929
	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
	  GART based hardware IOMMUs.

	  The GART supports full DMA access for devices with 32-bit access
	  limitations, on systems with more than 3 GB. This is usually needed
	  for USB, sound, many IDE/SATA chipsets and some other devices.

	  Newer systems typically have a modern AMD IOMMU, supported via
	  the CONFIG_AMD_IOMMU=y config option.

	  In normal configurations this driver is only active when needed:
	  there's more than 3 GB of memory and the system contains a
	  32-bit limited device.

	  If unsure, say Y.
930

931
config MAXSMP
932
	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
933
	depends on X86_64 && SMP && DEBUG_KERNEL
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934
	select CPUMASK_OFFSTACK
935
	help
936
	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
937
	  If unsure, say N.
938

939 940 941 942 943 944 945 946 947 948 949 950 951 952 953
#
# The maximum number of CPUs supported:
#
# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
# and which can be configured interactively in the
# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
#
# The ranges are different on 32-bit and 64-bit kernels, depending on
# hardware capabilities and scalability features of the kernel.
#
# ( If MAXSMP is enabled we just use the highest possible value and disable
#   interactive configuration. )
#

config NR_CPUS_RANGE_BEGIN
954
	int
955 956 957
	default NR_CPUS_RANGE_END if MAXSMP
	default    1 if !SMP
	default    2
958

959
config NR_CPUS_RANGE_END
960
	int
961 962 963 964
	depends on X86_32
	default   64 if  SMP &&  X86_BIGSMP
	default    8 if  SMP && !X86_BIGSMP
	default    1 if !SMP
965

966
config NR_CPUS_RANGE_END
967
	int
968
	depends on X86_64
969 970
	default 8192 if  SMP && CPUMASK_OFFSTACK
	default  512 if  SMP && !CPUMASK_OFFSTACK
971
	default    1 if !SMP
972

973
config NR_CPUS_DEFAULT
974 975
	int
	depends on X86_32
976 977 978
	default   32 if  X86_BIGSMP
	default    8 if  SMP
	default    1 if !SMP
979

980
config NR_CPUS_DEFAULT
981 982
	int
	depends on X86_64
983 984 985
	default 8192 if  MAXSMP
	default   64 if  SMP
	default    1 if !SMP
986

987
config NR_CPUS
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988
	int "Maximum number of CPUs" if SMP && !MAXSMP
989 990
	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
	default NR_CPUS_DEFAULT
991
	help
992
	  This allows you to specify the maximum number of CPUs which this
J
Josh Boyer 已提交
993
	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
994
	  supported value is 8192, otherwise the maximum value is 512.  The
995 996
	  minimum value which makes sense is 2.

997 998
	  This is purely to save memory: each supported CPU adds about 8KB
	  to the kernel image.
999 1000

config SCHED_SMT
1001
	def_bool y if SMP
1002 1003

config SCHED_MC
1004 1005
	def_bool y
	prompt "Multi-core scheduler support"
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Borislav Petkov 已提交
1006
	depends on SMP
1007
	help
1008 1009 1010 1011
	  Multi-core scheduler support improves the CPU scheduler's decision
	  making when dealing with multi-core CPU chips at a cost of slightly
	  increased overhead in some places. If unsure say N here.

1012 1013
config SCHED_MC_PRIO
	bool "CPU core priorities scheduler support"
1014 1015 1016
	depends on SCHED_MC && CPU_SUP_INTEL
	select X86_INTEL_PSTATE
	select CPU_FREQ
1017
	default y
1018
	help
1019 1020 1021 1022
	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
	  core ordering determined at manufacturing time, which allows
	  certain cores to reach higher turbo frequencies (when running
	  single threaded workloads) than others.
1023

1024 1025 1026 1027
	  Enabling this kernel feature teaches the scheduler about
	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
	  scheduler's CPU selection logic accordingly, so that higher
	  overall system performance can be achieved.
1028

1029
	  This feature will have no effect on CPUs without this feature.
1030

1031
	  If unsure say Y here.
1032

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Thomas Gleixner 已提交
1033
config UP_LATE_INIT
1034 1035
	def_bool y
	depends on !SMP && X86_LOCAL_APIC
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Thomas Gleixner 已提交
1036

1037
config X86_UP_APIC
1038 1039
	bool "Local APIC support on uniprocessors" if !PCI_MSI
	default PCI_MSI
1040
	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1041
	help
1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053
	  A local APIC (Advanced Programmable Interrupt Controller) is an
	  integrated interrupt controller in the CPU. If you have a single-CPU
	  system which has a processor with a local APIC, you can say Y here to
	  enable and use it. If you say Y here even though your machine doesn't
	  have a local APIC, then the kernel will still run with no slowdown at
	  all. The local APIC supports CPU-generated self-interrupts (timer,
	  performance counters), and the NMI watchdog which detects hard
	  lockups.

config X86_UP_IOAPIC
	bool "IO-APIC support on uniprocessors"
	depends on X86_UP_APIC
1054
	help
1055 1056 1057 1058 1059 1060 1061 1062 1063
	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
	  SMP-capable replacement for PC-style interrupt controllers. Most
	  SMP systems and many recent uniprocessor systems have one.

	  If you have a single-CPU system with an IO-APIC, you can say Y here
	  to use it. If you say Y here even though your machine doesn't have
	  an IO-APIC, then the kernel will still run with no slowdown at all.

config X86_LOCAL_APIC
1064
	def_bool y
1065
	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1066
	select IRQ_DOMAIN_HIERARCHY
1067
	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1068 1069

config X86_IO_APIC
1070 1071
	def_bool y
	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1072

1073 1074 1075
config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
	bool "Reroute for broken boot IRQs"
	depends on X86_IO_APIC
1076
	help
1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095
	  This option enables a workaround that fixes a source of
	  spurious interrupts. This is recommended when threaded
	  interrupt handling is used on systems where the generation of
	  superfluous "boot interrupts" cannot be disabled.

	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
	  kernel does during interrupt handling). On chipsets where this
	  boot IRQ generation cannot be disabled, this workaround keeps
	  the original IRQ line masked so that only the equivalent "boot
	  IRQ" is delivered to the CPUs. The workaround also tells the
	  kernel to set up the IRQ handler on the boot IRQ line. In this
	  way only one interrupt is delivered to the kernel. Otherwise
	  the spurious second interrupt may cause the kernel to bring
	  down (vital) interrupt lines.

	  Only affects "broken" chipsets. Interrupt sharing may be
	  increased on these systems.

1096
config X86_MCE
1097
	bool "Machine Check / overheating reporting"
1098
	select GENERIC_ALLOCATOR
1099
	default y
1100
	help
1101 1102
	  Machine Check support allows the processor to notify the
	  kernel if it detects a problem (e.g. overheating, data corruption).
1103
	  The action the kernel takes depends on the severity of the problem,
1104
	  ranging from warning messages to halting the machine.
1105

1106 1107 1108
config X86_MCELOG_LEGACY
	bool "Support for deprecated /dev/mcelog character device"
	depends on X86_MCE
1109
	help
1110 1111 1112 1113
	  Enable support for /dev/mcelog which is needed by the old mcelog
	  userspace logging daemon. Consider switching to the new generation
	  rasdaemon solution.

1114
config X86_MCE_INTEL
1115 1116
	def_bool y
	prompt "Intel MCE features"
1117
	depends on X86_MCE && X86_LOCAL_APIC
1118
	help
1119 1120 1121 1122
	   Additional support for intel specific MCE features such as
	   the thermal monitor.

config X86_MCE_AMD
1123 1124
	def_bool y
	prompt "AMD MCE features"
1125
	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1126
	help
1127 1128 1129
	   Additional support for AMD specific MCE features such as
	   the DRAM Error Threshold.

1130
config X86_ANCIENT_MCE
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1131
	bool "Support for old Pentium 5 / WinChip machine checks"
1132
	depends on X86_32 && X86_MCE
1133
	help
1134
	  Include support for machine check handling on old Pentium 5 or WinChip
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1135
	  systems. These typically need to be enabled explicitly on the command
1136
	  line.
1137

1138 1139
config X86_MCE_THRESHOLD
	depends on X86_MCE_AMD || X86_MCE_INTEL
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1140
	def_bool y
1141

1142
config X86_MCE_INJECT
1143
	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1144
	tristate "Machine check injector support"
1145
	help
1146 1147 1148 1149
	  Provide support for injecting machine checks for testing purposes.
	  If you don't know what a machine check is and you don't do kernel
	  QA it is safe to say n.

1150
source "arch/x86/events/Kconfig"
1151

1152
config X86_LEGACY_VM86
1153
	bool "Legacy VM86 support"
1154
	depends on X86_32
1155
	help
1156 1157 1158 1159 1160 1161 1162 1163
	  This option allows user programs to put the CPU into V8086
	  mode, which is an 80286-era approximation of 16-bit real mode.

	  Some very old versions of X and/or vbetool require this option
	  for user mode setting.  Similarly, DOSEMU will use it if
	  available to accelerate real mode DOS programs.  However, any
	  recent version of DOSEMU, X, or vbetool should be fully
	  functional even without kernel VM86 support, as they will all
1164 1165 1166 1167
	  fall back to software emulation. Nevertheless, if you are using
	  a 16-bit DOS program where 16-bit performance matters, vm86
	  mode might be faster than emulation and you might want to
	  enable this option.
1168

1169 1170 1171 1172
	  Note that any app that works on a 64-bit kernel is unlikely to
	  need this option, as 64-bit kernels don't, and can't, support
	  V8086 mode. This option is also unrelated to 16-bit protected
	  mode and is not needed to run most 16-bit programs under Wine.
1173

1174 1175
	  Enabling this option increases the complexity of the kernel
	  and slows down exception handling a tiny bit.
1176

1177
	  If unsure, say N here.
1178 1179

config VM86
1180 1181
	bool
	default X86_LEGACY_VM86
1182 1183 1184 1185

config X86_16BIT
	bool "Enable support for 16-bit segments" if EXPERT
	default y
1186
	depends on MODIFY_LDT_SYSCALL
1187
	help
1188 1189 1190 1191 1192 1193 1194 1195
	  This option is required by programs like Wine to run 16-bit
	  protected mode legacy code on x86 processors.  Disabling
	  this option saves about 300 bytes on i386, or around 6K text
	  plus 16K runtime memory on x86-64,

config X86_ESPFIX32
	def_bool y
	depends on X86_16BIT && X86_32
1196

1197 1198
config X86_ESPFIX64
	def_bool y
1199
	depends on X86_16BIT && X86_64
1200

1201
config X86_VSYSCALL_EMULATION
1202 1203 1204
	bool "Enable vsyscall emulation" if EXPERT
	default y
	depends on X86_64
1205
	help
1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218
	 This enables emulation of the legacy vsyscall page.  Disabling
	 it is roughly equivalent to booting with vsyscall=none, except
	 that it will also disable the helpful warning if a program
	 tries to use a vsyscall.  With this option set to N, offending
	 programs will just segfault, citing addresses of the form
	 0xffffffffff600?00.

	 This option is required by many programs built before 2013, and
	 care should be used even with newer programs if set to N.

	 Disabling this option saves about 7K of kernel size and
	 possibly 4K of additional runtime pagetable memory.

1219 1220
config X86_IOPL_IOPERM
	bool "IOPERM and IOPL Emulation"
1221
	default y
1222
	help
1223 1224 1225
	  This enables the ioperm() and iopl() syscalls which are necessary
	  for legacy applications.

1226 1227 1228 1229 1230 1231 1232 1233
	  Legacy IOPL support is an overbroad mechanism which allows user
	  space aside of accessing all 65536 I/O ports also to disable
	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
	  capabilities and permission from potentially active security
	  modules.

	  The emulation restricts the functionality of the syscall to
	  only allowing the full range I/O port access, but prevents the
1234 1235
	  ability to disable interrupts from user space which would be
	  granted if the hardware IOPL mechanism would be used.
1236

1237 1238 1239
config TOSHIBA
	tristate "Toshiba Laptop support"
	depends on X86_32
1240
	help
1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253
	  This adds a driver to safely access the System Management Mode of
	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
	  not work on models with a Phoenix BIOS. The System Management Mode
	  is used to set the BIOS and power saving options on Toshiba portables.

	  For information on utilities to make use of this driver see the
	  Toshiba Linux utilities web site at:
	  <http://www.buzzard.org.uk/toshiba/>.

	  Say Y if you intend to run this kernel on a Toshiba portable.
	  Say N otherwise.

config I8K
1254
	tristate "Dell i8k legacy laptop support"
1255
	select HWMON
1256
	select SENSORS_DELL_SMM
1257
	help
1258 1259 1260 1261 1262 1263 1264 1265 1266
	  This option enables legacy /proc/i8k userspace interface in hwmon
	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
	  temperature and allows controlling fan speeds of Dell laptops via
	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
	  it reports also power and hotkey status. For fan speed control is
	  needed userspace package i8kutils.

	  Say Y if you intend to run this kernel on old Dell laptops or want to
	  use userspace package i8kutils.
1267 1268 1269
	  Say N otherwise.

config X86_REBOOTFIXUPS
1270 1271
	bool "Enable X86 board specific fixups for reboot"
	depends on X86_32
1272
	help
1273 1274 1275 1276 1277 1278 1279
	  This enables chipset and/or board specific fixups to be done
	  in order to get reboot to work correctly. This is only needed on
	  some combinations of hardware and BIOS. The symptom, for which
	  this config is intended, is when reboot ends with a stalled/hung
	  system.

	  Currently, the only fixup is for the Geode machines using
1280
	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1281 1282 1283 1284 1285 1286

	  Say Y if you want to enable the fixup. Currently, it's safe to
	  enable this option even if you don't need it.
	  Say N otherwise.

config MICROCODE
1287 1288
	bool "CPU microcode loading support"
	default y
1289
	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1290
	help
1291
	  If you say Y here, you will be able to update the microcode on
1292 1293 1294 1295 1296 1297 1298
	  Intel and AMD processors. The Intel support is for the IA32 family,
	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
	  AMD support is for families 0x10 and later. You will obviously need
	  the actual microcode binary data itself which is not shipped with
	  the Linux kernel.

	  The preferred method to load microcode from a detached initrd is described
1299
	  in Documentation/x86/microcode.rst. For that you need to enable
1300 1301 1302
	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
	  initrd for microcode blobs.

1303 1304 1305
	  In addition, you can build the microcode into the kernel. For that you
	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
	  config option.
1306

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config MICROCODE_INTEL
1308
	bool "Intel microcode loading support"
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1309 1310
	depends on MICROCODE
	default MICROCODE
1311
	help
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1312 1313 1314
	  This options enables microcode patch loading support for Intel
	  processors.

1315 1316 1317
	  For the current Intel microcode data package go to
	  <https://downloadcenter.intel.com> and search for
	  'Linux Processor Microcode Data File'.
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1318

1319
config MICROCODE_AMD
1320
	bool "AMD microcode loading support"
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1321
	depends on MICROCODE
1322
	help
I
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1323 1324
	  If you select this option, microcode patch loading support for AMD
	  processors will be enabled.
1325

I
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1326
config MICROCODE_OLD_INTERFACE
1327 1328
	bool "Ancient loading interface (DEPRECATED)"
	default n
1329
	depends on MICROCODE
1330
	help
1331 1332 1333 1334 1335
	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
	  which was used by userspace tools like iucode_tool and microcode.ctl.
	  It is inadequate because it runs too late to be able to properly
	  load microcode on a machine and it needs special tools. Instead, you
	  should've switched to the early loading method with the initrd or
1336
	  builtin microcode by now: Documentation/x86/microcode.rst
1337 1338 1339

config X86_MSR
	tristate "/dev/cpu/*/msr - Model-specific register support"
1340
	help
1341 1342 1343 1344 1345 1346 1347 1348
	  This device gives privileged processes access to the x86
	  Model-Specific Registers (MSRs).  It is a character device with
	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
	  MSR accesses are directed to a specific CPU on multi-processor
	  systems.

config X86_CPUID
	tristate "/dev/cpu/*/cpuid - CPU information support"
1349
	help
1350 1351 1352 1353 1354 1355 1356
	  This device gives processes access to the x86 CPUID instruction to
	  be executed on a specific processor.  It is a character device
	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
	  /dev/cpu/31/cpuid.

choice
	prompt "High Memory Support"
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	default HIGHMEM4G
1358 1359 1360 1361
	depends on X86_32

config NOHIGHMEM
	bool "off"
1362
	help
1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397
	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
	  However, the address space of 32-bit x86 processors is only 4
	  Gigabytes large. That means that, if you have a large amount of
	  physical memory, not all of it can be "permanently mapped" by the
	  kernel. The physical memory that's not permanently mapped is called
	  "high memory".

	  If you are compiling a kernel which will never run on a machine with
	  more than 1 Gigabyte total physical RAM, answer "off" here (default
	  choice and suitable for most users). This will result in a "3GB/1GB"
	  split: 3GB are mapped so that each process sees a 3GB virtual memory
	  space and the remaining part of the 4GB virtual memory space is used
	  by the kernel to permanently map as much physical memory as
	  possible.

	  If the machine has between 1 and 4 Gigabytes physical RAM, then
	  answer "4GB" here.

	  If more than 4 Gigabytes is used then answer "64GB" here. This
	  selection turns Intel PAE (Physical Address Extension) mode on.
	  PAE implements 3-level paging on IA32 processors. PAE is fully
	  supported by Linux, PAE mode is implemented on all recent Intel
	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
	  then the kernel will not boot on CPUs that don't support PAE!

	  The actual amount of total physical memory will either be
	  auto detected or can be forced by using a kernel command line option
	  such as "mem=256M". (Try "man bootparam" or see the documentation of
	  your boot loader (lilo or loadlin) about how to pass options to the
	  kernel at boot time.)

	  If unsure, say "off".

config HIGHMEM4G
	bool "4GB"
1398
	help
1399 1400 1401 1402 1403
	  Select this if you have a 32-bit processor and between 1 and 4
	  gigabytes of physical RAM.

config HIGHMEM64G
	bool "64GB"
1404
	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1405
	select X86_PAE
1406
	help
1407 1408 1409 1410 1411 1412
	  Select this if you have a 32-bit processor and more than 4
	  gigabytes of physical RAM.

endchoice

choice
1413
	prompt "Memory split" if EXPERT
1414 1415
	default VMSPLIT_3G
	depends on X86_32
1416
	help
1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455
	  Select the desired split between kernel and user memory.

	  If the address range available to the kernel is less than the
	  physical memory installed, the remaining memory will be available
	  as "high memory". Accessing high memory is a little more costly
	  than low memory, as it needs to be mapped into the kernel first.
	  Note that increasing the kernel address space limits the range
	  available to user programs, making the address space there
	  tighter.  Selecting anything other than the default 3G/1G split
	  will also likely make your kernel incompatible with binary-only
	  kernel modules.

	  If you are not absolutely sure what you are doing, leave this
	  option alone!

	config VMSPLIT_3G
		bool "3G/1G user/kernel split"
	config VMSPLIT_3G_OPT
		depends on !X86_PAE
		bool "3G/1G user/kernel split (for full 1G low memory)"
	config VMSPLIT_2G
		bool "2G/2G user/kernel split"
	config VMSPLIT_2G_OPT
		depends on !X86_PAE
		bool "2G/2G user/kernel split (for full 2G low memory)"
	config VMSPLIT_1G
		bool "1G/3G user/kernel split"
endchoice

config PAGE_OFFSET
	hex
	default 0xB0000000 if VMSPLIT_3G_OPT
	default 0x80000000 if VMSPLIT_2G
	default 0x78000000 if VMSPLIT_2G_OPT
	default 0x40000000 if VMSPLIT_1G
	default 0xC0000000
	depends on X86_32

config HIGHMEM
1456
	def_bool y
1457 1458 1459
	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)

config X86_PAE
1460
	bool "PAE (Physical Address Extension) Support"
1461
	depends on X86_32 && !HIGHMEM4G
1462
	select PHYS_ADDR_T_64BIT
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Christian Melki 已提交
1463
	select SWIOTLB
1464
	help
1465 1466 1467 1468 1469
	  PAE is required for NX support, and furthermore enables
	  larger swapspace support for non-overcommit purposes. It
	  has the cost of more pagetable lookup overhead, and also
	  consumes more pagetable space per process.

1470 1471
config X86_5LEVEL
	bool "Enable 5-level page tables support"
1472
	default y
1473
	select DYNAMIC_MEMORY_LAYOUT
1474
	select SPARSEMEM_VMEMMAP
1475
	depends on X86_64
1476
	help
1477 1478 1479 1480 1481 1482
	  5-level paging enables access to larger address space:
	  upto 128 PiB of virtual address space and 4 PiB of
	  physical address space.

	  It will be supported by future Intel CPUs.

1483 1484
	  A kernel with the option enabled can be booted on machines that
	  support 4- or 5-level paging.
1485

1486
	  See Documentation/x86/x86_64/5level-paging.rst for more
1487 1488 1489 1490
	  information.

	  Say N if unsure.

1491
config X86_DIRECT_GBPAGES
1492
	def_bool y
1493
	depends on X86_64
1494
	help
1495 1496 1497 1498
	  Certain kernel features effectively disable kernel
	  linear 1 GB mappings (even if the CPU otherwise
	  supports them), so don't confuse the user by printing
	  that we have them enabled.
1499

1500 1501 1502
config X86_CPA_STATISTICS
	bool "Enable statistic for Change Page Attribute"
	depends on DEBUG_FS
1503
	help
1504
	  Expose statistics about the Change Page Attribute mechanism, which
1505
	  helps to determine the effectiveness of preserving large and huge
1506 1507
	  page mappings when mapping protections are changed.

1508 1509 1510
config AMD_MEM_ENCRYPT
	bool "AMD Secure Memory Encryption (SME) support"
	depends on X86_64 && CPU_SUP_AMD
1511
	select DMA_COHERENT_POOL
1512
	select DYNAMIC_PHYSICAL_MASK
1513
	select ARCH_USE_MEMREMAP_PROT
1514
	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1515
	select INSTRUCTION_DECODER
1516
	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
1517
	help
1518 1519 1520 1521 1522 1523 1524 1525
	  Say yes to enable support for the encryption of system memory.
	  This requires an AMD processor that supports Secure Memory
	  Encryption (SME).

config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
	bool "Activate AMD Secure Memory Encryption (SME) by default"
	default y
	depends on AMD_MEM_ENCRYPT
1526
	help
1527 1528 1529 1530 1531 1532 1533 1534 1535
	  Say yes to have system memory encrypted by default if running on
	  an AMD processor that supports Secure Memory Encryption (SME).

	  If set to Y, then the encryption of system memory can be
	  deactivated with the mem_encrypt=off command line option.

	  If set to N, then the encryption of system memory can be
	  activated with the mem_encrypt=on command line option.

1536 1537
# Common NUMA Features
config NUMA
1538
	bool "NUMA Memory Allocation and Scheduler Support"
1539
	depends on SMP
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H. Peter Anvin 已提交
1540 1541
	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
	default y if X86_BIGSMP
1542
	help
1543
	  Enable NUMA (Non-Uniform Memory Access) support.
1544

1545 1546 1547 1548
	  The kernel will try to allocate memory used by a CPU on the
	  local memory controller of the CPU and add some more
	  NUMA awareness to the kernel.

1549
	  For 64-bit this is recommended if the system is Intel Core i7
1550 1551
	  (or later), AMD Opteron, or EM64T NUMA.

H
H. Peter Anvin 已提交
1552
	  For 32-bit this is only needed if you boot a 32-bit
1553
	  kernel on a 64-bit NUMA platform.
1554 1555

	  Otherwise, you should say N.
1556

1557
config AMD_NUMA
1558 1559
	def_bool y
	prompt "Old style AMD Opteron NUMA detection"
1560
	depends on X86_64 && NUMA && PCI
1561
	help
1562 1563 1564 1565 1566
	  Enable AMD NUMA node topology detection.  You should say Y here if
	  you have a multi processor AMD system. This uses an old method to
	  read the NUMA configuration directly from the builtin Northbridge
	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
	  which also takes priority if both are compiled in.
1567 1568

config X86_64_ACPI_NUMA
1569 1570
	def_bool y
	prompt "ACPI NUMA detection"
1571 1572
	depends on X86_64 && NUMA && ACPI && PCI
	select ACPI_NUMA
1573
	help
1574 1575 1576 1577
	  Enable ACPI SRAT based node topology detection.

config NUMA_EMU
	bool "NUMA emulation"
1578
	depends on NUMA
1579
	help
1580 1581 1582 1583 1584
	  Enable NUMA emulation. A flat machine will be split
	  into virtual nodes when booted with "numa=fake=N", where N is the
	  number of nodes. This is only useful for debugging.

config NODES_SHIFT
1585
	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1586 1587
	range 1 10
	default "10" if MAXSMP
1588 1589
	default "6" if X86_64
	default "3"
1590
	depends on NUMA
1591
	help
1592
	  Specify the maximum number of NUMA Nodes available on the target
1593
	  system.  Increases memory reserved to accommodate various tables.
1594 1595 1596

config ARCH_FLATMEM_ENABLE
	def_bool y
1597
	depends on X86_32 && !NUMA
1598 1599 1600

config ARCH_SPARSEMEM_ENABLE
	def_bool y
1601
	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1602 1603 1604
	select SPARSEMEM_STATIC if X86_32
	select SPARSEMEM_VMEMMAP_ENABLE if X86_64

1605
config ARCH_SPARSEMEM_DEFAULT
1606
	def_bool X86_64 || (NUMA && X86_32)
1607

1608 1609
config ARCH_SELECT_MEMORY_MODEL
	def_bool y
1610
	depends on ARCH_SPARSEMEM_ENABLE
1611 1612

config ARCH_MEMORY_PROBE
1613
	bool "Enable sysfs memory/probe interface"
1614
	depends on X86_64 && MEMORY_HOTPLUG
1615 1616
	help
	  This option enables a sysfs memory/probe interface for testing.
1617
	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1618
	  If you are unsure how to answer this question, answer N.
1619

1620 1621 1622 1623
config ARCH_PROC_KCORE_TEXT
	def_bool y
	depends on X86_64 && PROC_KCORE

1624
config ILLEGAL_POINTER_VALUE
1625 1626 1627
	hex
	default 0 if X86_32
	default 0xdead000000000000 if X86_64
1628

1629 1630 1631
config X86_PMEM_LEGACY_DEVICE
	bool

1632
config X86_PMEM_LEGACY
1633
	tristate "Support non-standard NVDIMMs and ADR protected memory"
1634 1635
	depends on PHYS_ADDR_T_64BIT
	depends on BLK_DEV
1636
	select X86_PMEM_LEGACY_DEVICE
1637
	select NUMA_KEEP_MEMINFO if NUMA
1638
	select LIBNVDIMM
1639 1640 1641 1642 1643 1644 1645 1646
	help
	  Treat memory marked using the non-standard e820 type of 12 as used
	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
	  The kernel will offer these regions to the 'pmem' driver so
	  they can be used for persistent storage.

	  Say Y if unsure.

1647 1648
config HIGHPTE
	bool "Allocate 3rd-level pagetables from highmem"
J
Jan Beulich 已提交
1649
	depends on HIGHMEM
1650
	help
1651 1652 1653 1654 1655
	  The VM uses one page table entry for each page of physical memory.
	  For systems with a lot of RAM, this can be wasteful of precious
	  low memory.  Setting this option will put user-space page table
	  entries in high memory.

1656
config X86_CHECK_BIOS_CORRUPTION
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Ingo Molnar 已提交
1657
	bool "Check for low memory corruption"
1658
	help
I
Ingo Molnar 已提交
1659 1660 1661 1662 1663 1664 1665
	  Periodically check for memory corruption in low memory, which
	  is suspected to be caused by BIOS.  Even when enabled in the
	  configuration, it is disabled at runtime.  Enable it by
	  setting "memory_corruption_check=1" on the kernel command
	  line.  By default it scans the low 64k of memory every 60
	  seconds; see the memory_corruption_check_size and
	  memory_corruption_check_period parameters in
1666
	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
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Ingo Molnar 已提交
1667 1668 1669 1670 1671 1672 1673 1674 1675 1676

	  When enabled with the default parameters, this option has
	  almost no overhead, as it reserves a relatively small amount
	  of memory and scans it infrequently.  It both detects corruption
	  and prevents it from affecting the running system.

	  It is, however, intended as a diagnostic tool; if repeatable
	  BIOS-originated corruption always affects the same memory,
	  you can use memmap= to prevent the kernel from using that
	  memory.
1677

1678
config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
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Ingo Molnar 已提交
1679
	bool "Set the default setting of memory_corruption_check"
1680 1681
	depends on X86_CHECK_BIOS_CORRUPTION
	default y
1682
	help
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	  Set whether the default state of memory_corruption_check is
	  on or off.
1685

1686 1687
config MATH_EMULATION
	bool
1688
	depends on MODIFY_LDT_SYSCALL
1689
	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1690
	help
1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713
	  Linux can emulate a math coprocessor (used for floating point
	  operations) if you don't have one. 486DX and Pentium processors have
	  a math coprocessor built in, 486SX and 386 do not, unless you added
	  a 487DX or 387, respectively. (The messages during boot time can
	  give you some hints here ["man dmesg"].) Everyone needs either a
	  coprocessor or this emulation.

	  If you don't have a math coprocessor, you need to say Y here; if you
	  say Y here even though you have a coprocessor, the coprocessor will
	  be used nevertheless. (This behavior can be changed with the kernel
	  command line option "no387", which comes handy if your coprocessor
	  is broken. Try "man bootparam" or see the documentation of your boot
	  loader (lilo or loadlin) about how to pass options to the kernel at
	  boot time.) This means that it is a good idea to say Y here if you
	  intend to use this kernel on different machines.

	  More information about the internals of the Linux math coprocessor
	  emulation can be found in <file:arch/x86/math-emu/README>.

	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
	  kernel, it won't hurt.

config MTRR
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	def_bool y
1715
	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1716
	help
1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745
	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
	  the Memory Type Range Registers (MTRRs) may be used to control
	  processor access to memory ranges. This is most useful if you have
	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
	  allows bus write transfers to be combined into a larger transfer
	  before bursting over the PCI/AGP bus. This can increase performance
	  of image write operations 2.5 times or more. Saying Y here creates a
	  /proc/mtrr file which may be used to manipulate your processor's
	  MTRRs. Typically the X server should use this.

	  This code has a reasonably generic interface so that similar
	  control registers on other processors can be easily supported
	  as well:

	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
	  Registers (ARRs) which provide a similar functionality to MTRRs. For
	  these, the ARRs are used to emulate the MTRRs.
	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
	  write-combining. All of these processors are supported by this code
	  and it makes sense to say Y here if you have one of them.

	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
	  can lead to all sorts of problems, so it's good to say Y here.

	  You can safely say Y even if your machine doesn't have MTRRs, you'll
	  just add about 9 KB to your kernel.

1746
	  See <file:Documentation/x86/mtrr.rst> for more information.
1747

1748
config MTRR_SANITIZER
1749
	def_bool y
1750 1751
	prompt "MTRR cleanup support"
	depends on MTRR
1752
	help
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	  Convert MTRR layout from continuous to discrete, so X drivers can
	  add writeback entries.
1755

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	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1757
	  The largest mtrr entry size for a continuous block can be set with
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	  mtrr_chunk_size.
1759

1760
	  If unsure, say Y.
1761 1762

config MTRR_SANITIZER_ENABLE_DEFAULT
1763 1764 1765
	int "MTRR cleanup enable value (0-1)"
	range 0 1
	default "0"
1766
	depends on MTRR_SANITIZER
1767
	help
1768
	  Enable mtrr cleanup default value
1769

1770 1771 1772 1773 1774
config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
	int "MTRR cleanup spare reg num (0-7)"
	range 0 7
	default "1"
	depends on MTRR_SANITIZER
1775
	help
1776
	  mtrr cleanup spare entries default, it can be changed via
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	  mtrr_spare_reg_nr=N on the kernel command line.
1778

1779
config X86_PAT
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	def_bool y
1781
	prompt "x86 PAT support" if EXPERT
1782
	depends on MTRR
1783
	help
1784
	  Use PAT attributes to setup page level cache control.
1785

1786 1787 1788 1789
	  PATs are the modern equivalents of MTRRs and are much more
	  flexible than MTRRs.

	  Say N here if you see bootup problems (boot crash, boot hang,
1790
	  spontaneous reboots) or a non-working video driver.
1791 1792 1793

	  If unsure, say Y.

1794 1795 1796 1797
config ARCH_USES_PG_UNCACHED
	def_bool y
	depends on X86_PAT

1798 1799 1800
config ARCH_RANDOM
	def_bool y
	prompt "x86 architectural random number generator" if EXPERT
1801
	help
1802 1803 1804 1805 1806
	  Enable the x86 architectural RDRAND instruction
	  (Intel Bull Mountain technology) to generate random numbers.
	  If supported, this is a high bandwidth, cryptographically
	  secure hardware random number generator.

1807 1808 1809
config X86_SMAP
	def_bool y
	prompt "Supervisor Mode Access Prevention" if EXPERT
1810
	help
1811 1812 1813 1814 1815 1816 1817
	  Supervisor Mode Access Prevention (SMAP) is a security
	  feature in newer Intel processors.  There is a small
	  performance cost if this enabled and turned on; there is
	  also a small increase in the kernel size if this is enabled.

	  If unsure, say Y.

1818
config X86_UMIP
1819
	def_bool y
1820
	prompt "User Mode Instruction Prevention" if EXPERT
1821
	help
1822 1823 1824 1825 1826
	  User Mode Instruction Prevention (UMIP) is a security feature in
	  some x86 processors. If enabled, a general protection fault is
	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
	  executed in user mode. These instructions unnecessarily expose
	  information about the hardware state.
1827 1828 1829 1830 1831

	  The vast majority of applications do not use these instructions.
	  For the very few that do, software emulation is provided in
	  specific cases in protected and virtual-8086 modes. Emulated
	  results are dummy.
1832

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config X86_INTEL_MEMORY_PROTECTION_KEYS
1834
	prompt "Memory Protection Keys"
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1835
	def_bool y
1836
	# Note: only available in 64-bit mode
1837
	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1838 1839
	select ARCH_USES_HIGH_VMA_FLAGS
	select ARCH_HAS_PKEYS
1840
	help
1841 1842 1843 1844
	  Memory Protection Keys provides a mechanism for enforcing
	  page-based protections, but without requiring modification of the
	  page tables when an application changes protection domains.

1845
	  For details, see Documentation/core-api/protection-keys.rst
1846 1847

	  If unsure, say y.
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1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893
choice
	prompt "TSX enable mode"
	depends on CPU_SUP_INTEL
	default X86_INTEL_TSX_MODE_OFF
	help
	  Intel's TSX (Transactional Synchronization Extensions) feature
	  allows to optimize locking protocols through lock elision which
	  can lead to a noticeable performance boost.

	  On the other hand it has been shown that TSX can be exploited
	  to form side channel attacks (e.g. TAA) and chances are there
	  will be more of those attacks discovered in the future.

	  Therefore TSX is not enabled by default (aka tsx=off). An admin
	  might override this decision by tsx=on the command line parameter.
	  Even with TSX enabled, the kernel will attempt to enable the best
	  possible TAA mitigation setting depending on the microcode available
	  for the particular machine.

	  This option allows to set the default tsx mode between tsx=on, =off
	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
	  details.

	  Say off if not sure, auto if TSX is in use but it should be used on safe
	  platforms or on if TSX is in use and the security aspect of tsx is not
	  relevant.

config X86_INTEL_TSX_MODE_OFF
	bool "off"
	help
	  TSX is disabled if possible - equals to tsx=off command line parameter.

config X86_INTEL_TSX_MODE_ON
	bool "on"
	help
	  TSX is always enabled on TSX capable HW - equals the tsx=on command
	  line parameter.

config X86_INTEL_TSX_MODE_AUTO
	bool "auto"
	help
	  TSX is enabled on TSX capable HW that is believed to be safe against
	  side channel attacks- equals the tsx=auto command line parameter.
endchoice

1894 1895 1896 1897 1898 1899 1900
config X86_SGX
	bool "Software Guard eXtensions (SGX)"
	depends on X86_64 && CPU_SUP_INTEL
	depends on CRYPTO=y
	depends on CRYPTO_SHA256=y
	select SRCU
	select MMU_NOTIFIER
1901
	select NUMA_KEEP_MEMINFO if NUMA
1902 1903 1904 1905 1906 1907 1908 1909 1910 1911
	help
	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
	  that can be used by applications to set aside private regions of code
	  and data, referred to as enclaves. An enclave's private memory can
	  only be accessed by code running within the enclave. Accesses from
	  outside the enclave, including other enclaves, are disallowed by
	  hardware.

	  If unsure, say N.

1912
config EFI
1913
	bool "EFI runtime service support"
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	depends on ACPI
1915
	select UCS2_STRING
1916
	select EFI_RUNTIME_WRAPPERS
1917
	help
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	  This enables the kernel to use EFI runtime services that are
	  available (such as the EFI variable services).
1920

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	  This option is only useful on systems that have EFI firmware.
	  In addition, you should use the latest ELILO loader available
	  at <http://elilo.sourceforge.net> in order to take advantage
	  of EFI runtime services. However, even with this option, the
	  resultant kernel should continue to boot on existing non-EFI
	  platforms.
1927

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config EFI_STUB
1929 1930 1931 1932
	bool "EFI stub support"
	depends on EFI && !X86_USE_3DNOW
	depends on $(cc-option,-mabi=ms) || X86_32
	select RELOCATABLE
1933
	help
1934
	  This kernel feature allows a bzImage to be loaded directly
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	  by EFI firmware without the use of a bootloader.

1937
	  See Documentation/admin-guide/efi-stub.rst for more information.
1938

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config EFI_MIXED
	bool "EFI mixed-mode support"
	depends on EFI_STUB && X86_64
1942
	help
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1943 1944 1945 1946 1947 1948 1949 1950 1951 1952
	   Enabling this feature allows a 64-bit kernel to be booted
	   on a 32-bit firmware, provided that your CPU supports 64-bit
	   mode.

	   Note that it is not possible to boot a mixed-mode enabled
	   kernel via the EFI boot stub - a bootloader that supports
	   the EFI handover protocol must be used.

	   If unsure, say N.

1953
source "kernel/Kconfig.hz"
1954 1955 1956

config KEXEC
	bool "kexec system call"
1957
	select KEXEC_CORE
1958
	help
1959 1960 1961 1962 1963 1964 1965 1966 1967
	  kexec is a system call that implements the ability to shutdown your
	  current kernel, and to start another kernel.  It is like a reboot
	  but it is independent of the system firmware.   And like a reboot
	  you can start any kernel with it, not just Linux.

	  The name comes from the similarity to the exec system call.

	  It is an ongoing process to be certain the hardware in a machine
	  is properly shutdown, so do not be surprised if this code does not
1968 1969 1970
	  initially work for you.  As of this writing the exact hardware
	  interface is strongly in flux, so no good recommendation can be
	  made.
1971

1972 1973
config KEXEC_FILE
	bool "kexec file based system call"
1974
	select KEXEC_CORE
1975 1976 1977 1978
	select BUILD_BIN2C
	depends on X86_64
	depends on CRYPTO=y
	depends on CRYPTO_SHA256=y
1979
	help
1980 1981 1982 1983 1984
	  This is new version of kexec system call. This system call is
	  file based and takes file descriptors as system call argument
	  for kernel and initramfs as opposed to list of segments as
	  accepted by previous system call.

1985 1986 1987
config ARCH_HAS_KEXEC_PURGATORY
	def_bool KEXEC_FILE

1988
config KEXEC_SIG
1989
	bool "Verify kernel signature during kexec_file_load() syscall"
1990
	depends on KEXEC_FILE
1991
	help
1992

1993 1994 1995 1996 1997 1998
	  This option makes the kexec_file_load() syscall check for a valid
	  signature of the kernel image.  The image can still be loaded without
	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
	  there's a signature that we can check, then it must be valid.

	  In addition to this option, you need to enable signature
1999 2000
	  verification for the corresponding kernel image type being
	  loaded in order for this to work.
2001

2002 2003 2004
config KEXEC_SIG_FORCE
	bool "Require a valid signature in kexec_file_load() syscall"
	depends on KEXEC_SIG
2005
	help
2006 2007 2008
	  This option makes kernel signature verification mandatory for
	  the kexec_file_load() syscall.

2009 2010
config KEXEC_BZIMAGE_VERIFY_SIG
	bool "Enable bzImage signature verification support"
2011
	depends on KEXEC_SIG
2012 2013
	depends on SIGNED_PE_FILE_VERIFICATION
	select SYSTEM_TRUSTED_KEYRING
2014
	help
2015 2016
	  Enable bzImage signature verification support.

2017
config CRASH_DUMP
2018
	bool "kernel crash dumps"
2019
	depends on X86_64 || (X86_32 && HIGHMEM)
2020
	help
2021 2022 2023 2024 2025 2026 2027 2028
	  Generate crash dump after being started by kexec.
	  This should be normally only set in special crash dump kernels
	  which are loaded in the main kernel with kexec-tools into
	  a specially reserved region and then later executed after
	  a crash by kdump/kexec. The crash dump kernel must be compiled
	  to a memory address not used by the main kernel or BIOS using
	  PHYSICAL_START, or it must be built as a relocatable image
	  (CONFIG_RELOCATABLE=y).
2029
	  For more details see Documentation/admin-guide/kdump/kdump.rst
2030

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2031
config KEXEC_JUMP
2032
	bool "kexec jump"
2033
	depends on KEXEC && HIBERNATION
2034
	help
2035 2036
	  Jump between original kernel and kexeced kernel and invoke
	  code in physical address mode via KEXEC
H
Huang Ying 已提交
2037

2038
config PHYSICAL_START
2039
	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2040
	default "0x1000000"
2041
	help
2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058
	  This gives the physical address where the kernel is loaded.

	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
	  bzImage will decompress itself to above physical address and
	  run from there. Otherwise, bzImage will run from the address where
	  it has been loaded by the boot loader and will ignore above physical
	  address.

	  In normal kdump cases one does not have to set/change this option
	  as now bzImage can be compiled as a completely relocatable image
	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
	  address. This option is mainly useful for the folks who don't want
	  to use a bzImage for capturing the crash dump and want to use a
	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
	  to be specifically compiled to run from a specific memory area
	  (normally a reserved region) and this option comes handy.

2059 2060 2061 2062 2063 2064 2065
	  So if you are using bzImage for capturing the crash dump,
	  leave the value here unchanged to 0x1000000 and set
	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
	  for capturing the crash dump change this value to start of
	  the reserved region.  In other words, it can be set based on
	  the "X" value as specified in the "crashkernel=YM@XM"
	  command line boot parameter passed to the panic-ed
2066
	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2067
	  for more details about crash dumps.
2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079

	  Usage of bzImage for capturing the crash dump is recommended as
	  one does not have to build two kernels. Same kernel can be used
	  as production kernel and capture kernel. Above option should have
	  gone away after relocatable bzImage support is introduced. But it
	  is present because there are users out there who continue to use
	  vmlinux for dump capture. This option should go away down the
	  line.

	  Don't change this unless you know what you are doing.

config RELOCATABLE
2080 2081
	bool "Build a relocatable kernel"
	default y
2082
	help
2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093
	  This builds a kernel image that retains relocation information
	  so it can be loaded someplace besides the default 1MB.
	  The relocations tend to make the kernel binary about 10% larger,
	  but are discarded at runtime.

	  One use is for the kexec on panic case where the recovery kernel
	  must live at a different physical address than the primary
	  kernel.

	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
	  it has been loaded at and the compile time physical address
2094
	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2095

2096
config RANDOMIZE_BASE
2097
	bool "Randomize the address of the kernel image (KASLR)"
2098
	depends on RELOCATABLE
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	default y
2100
	help
2101 2102 2103 2104 2105 2106 2107
	  In support of Kernel Address Space Layout Randomization (KASLR),
	  this randomizes the physical address at which the kernel image
	  is decompressed and the virtual address where the kernel
	  image is mapped, as a security feature that deters exploit
	  attempts relying on knowledge of the location of kernel
	  code internals.

2108 2109 2110 2111 2112 2113 2114 2115 2116 2117
	  On 64-bit, the kernel physical and virtual addresses are
	  randomized separately. The physical address will be anywhere
	  between 16MB and the top of physical memory (up to 64TB). The
	  virtual address will be randomized from 16MB up to 1GB (9 bits
	  of entropy). Note that this also reduces the memory space
	  available to kernel modules from 1.5GB to 1GB.

	  On 32-bit, the kernel physical and virtual addresses are
	  randomized together. They will be randomized from 16MB up to
	  512MB (8 bits of entropy).
2118 2119 2120 2121

	  Entropy is generated using the RDRAND instruction if it is
	  supported. If RDTSC is supported, its value is mixed into
	  the entropy pool as well. If neither RDRAND nor RDTSC are
2122 2123 2124 2125 2126 2127
	  supported, then entropy is read from the i8254 timer. The
	  usable entropy is limited by the kernel being built using
	  2GB addressing, and that PHYSICAL_ALIGN must be at a
	  minimum of 2MB. As a result, only 10 bits of entropy are
	  theoretically possible, but the implementations are further
	  limited due to memory layouts.
2128

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2129
	  If unsure, say Y.
2130 2131

# Relocation on x86 needs some additional build support
2132 2133
config X86_NEED_RELOCS
	def_bool y
2134
	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2135

2136
config PHYSICAL_ALIGN
2137
	hex "Alignment value to which kernel should be aligned"
2138
	default "0x200000"
2139 2140
	range 0x2000 0x1000000 if X86_32
	range 0x200000 0x1000000 if X86_64
2141
	help
2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157
	  This value puts the alignment restrictions on physical address
	  where kernel is loaded and run from. Kernel is compiled for an
	  address which meets above alignment restriction.

	  If bootloader loads the kernel at a non-aligned address and
	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
	  address aligned to above value and run from there.

	  If bootloader loads the kernel at a non-aligned address and
	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
	  load address and decompress itself to the address it has been
	  compiled for and run from there. The address for which kernel is
	  compiled already meets above alignment restrictions. Hence the
	  end result is that kernel runs from a physical address meeting
	  above alignment restrictions.

2158 2159 2160
	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
	  this value must be a multiple of 0x200000.

2161 2162
	  Don't change this unless you know what you are doing.

2163 2164
config DYNAMIC_MEMORY_LAYOUT
	bool
2165
	help
2166 2167 2168
	  This option makes base addresses of vmalloc and vmemmap as well as
	  __PAGE_OFFSET movable during boot.

2169 2170 2171 2172
config RANDOMIZE_MEMORY
	bool "Randomize the kernel memory sections"
	depends on X86_64
	depends on RANDOMIZE_BASE
2173
	select DYNAMIC_MEMORY_LAYOUT
2174
	default RANDOMIZE_BASE
2175
	help
2176 2177 2178 2179 2180 2181 2182 2183 2184
	   Randomizes the base virtual address of kernel memory sections
	   (physical memory mapping, vmalloc & vmemmap). This security feature
	   makes exploits relying on predictable memory locations less reliable.

	   The order of allocations remains unchanged. Entropy is generated in
	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
	   configuration have in average 30,000 different possible virtual
	   addresses for each memory section.

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	   If unsure, say Y.
2186

2187 2188 2189 2190 2191 2192 2193
config RANDOMIZE_MEMORY_PHYSICAL_PADDING
	hex "Physical memory mapping padding" if EXPERT
	depends on RANDOMIZE_MEMORY
	default "0xa" if MEMORY_HOTPLUG
	default "0x0"
	range 0x1 0x40 if MEMORY_HOTPLUG
	range 0x0 0x40
2194
	help
2195 2196 2197 2198 2199 2200 2201
	   Define the padding in terabytes added to the existing physical
	   memory size during kernel memory randomization. It is useful
	   for memory hotplug support but reduces the entropy available for
	   address randomization.

	   If unsure, leave at the default value.

2202
config HOTPLUG_CPU
2203
	def_bool y
2204
	depends on SMP
2205

2206 2207
config BOOTPARAM_HOTPLUG_CPU0
	bool "Set default setting of cpu0_hotpluggable"
2208
	depends on HOTPLUG_CPU
2209
	help
2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233
	  Set whether default state of cpu0_hotpluggable is on or off.

	  Say Y here to enable CPU0 hotplug by default. If this switch
	  is turned on, there is no need to give cpu0_hotplug kernel
	  parameter and the CPU0 hotplug feature is enabled by default.

	  Please note: there are two known CPU0 dependencies if you want
	  to enable the CPU0 hotplug feature either by this switch or by
	  cpu0_hotplug kernel parameter.

	  First, resume from hibernate or suspend always starts from CPU0.
	  So hibernate and suspend are prevented if CPU0 is offline.

	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
	  offline if any interrupt can not migrate out of CPU0. There may
	  be other CPU0 dependencies.

	  Please make sure the dependencies are under your control before
	  you enable this feature.

	  Say N if you don't want to enable CPU0 hotplug feature by default.
	  You still can enable the CPU0 hotplug feature at boot by kernel
	  parameter cpu0_hotplug.

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config DEBUG_HOTPLUG_CPU0
	def_bool n
	prompt "Debug CPU0 hotplug"
2237
	depends on HOTPLUG_CPU
2238
	help
F
Fenghua Yu 已提交
2239 2240 2241 2242 2243 2244 2245 2246 2247 2248
	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
	  soon as possible and boots up userspace with CPU0 offlined. User
	  can online CPU0 back after boot time.

	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
	  compilation or giving cpu0_hotplug kernel parameter at boot.

	  If unsure, say N.

2249
config COMPAT_VDSO
2250 2251
	def_bool n
	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2252
	depends on COMPAT_32
2253
	help
2254 2255 2256
	  Certain buggy versions of glibc will crash if they are
	  presented with a 32-bit vDSO that is not mapped at the address
	  indicated in its segment table.
R
Randy Dunlap 已提交
2257

2258 2259 2260 2261 2262
	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
	  the only released version with the bug, but OpenSUSE 9
	  contains a buggy "glibc 2.3.2".
2263

2264 2265 2266 2267 2268 2269 2270 2271 2272
	  The symptom of the bug is that everything crashes on startup, saying:
	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!

	  Saying Y here changes the default value of the vdso32 boot
	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
	  This works around the glibc bug but hurts performance.

	  If unsure, say N: if you are compiling your own kernel, you
	  are unlikely to be using a buggy version of glibc.
2273

2274 2275 2276
choice
	prompt "vsyscall table for legacy applications"
	depends on X86_64
2277
	default LEGACY_VSYSCALL_XONLY
2278 2279 2280 2281 2282 2283 2284
	help
	  Legacy user code that does not know how to find the vDSO expects
	  to be able to issue three syscalls by calling fixed addresses in
	  kernel space. Since this location is not randomized with ASLR,
	  it can be used to assist security vulnerability exploitation.

	  This setting can be changed at boot time via the kernel command
2285
	  line parameter vsyscall=[emulate|xonly|none].
2286 2287 2288 2289 2290

	  On a system with recent enough glibc (2.14 or newer) and no
	  static binaries, you can say None without a performance penalty
	  to improve security.

2291
	  If unsure, select "Emulate execution only".
2292 2293

	config LEGACY_VSYSCALL_EMULATE
2294
		bool "Full emulation"
2295
		help
2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316
		  The kernel traps and emulates calls into the fixed vsyscall
		  address mapping. This makes the mapping non-executable, but
		  it still contains readable known contents, which could be
		  used in certain rare security vulnerability exploits. This
		  configuration is recommended when using legacy userspace
		  that still uses vsyscalls along with legacy binary
		  instrumentation tools that require code to be readable.

		  An example of this type of legacy userspace is running
		  Pin on an old binary that still uses vsyscalls.

	config LEGACY_VSYSCALL_XONLY
		bool "Emulate execution only"
		help
		  The kernel traps and emulates calls into the fixed vsyscall
		  address mapping and does not allow reads.  This
		  configuration is recommended when userspace might use the
		  legacy vsyscall area but support for legacy binary
		  instrumentation of legacy code is not needed.  It mitigates
		  certain uses of the vsyscall area as an ASLR-bypassing
		  buffer.
2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328

	config LEGACY_VSYSCALL_NONE
		bool "None"
		help
		  There will be no vsyscall mapping at all. This will
		  eliminate any risk of ASLR bypass due to the vsyscall
		  fixed address mapping. Attempts to use the vsyscalls
		  will be reported to dmesg, so that either old or
		  malicious userspace programs can be identified.

endchoice

2329 2330
config CMDLINE_BOOL
	bool "Built-in kernel command line"
2331
	help
2332 2333 2334 2335 2336 2337 2338 2339
	  Allow for specifying boot arguments to the kernel at
	  build time.  On some systems (e.g. embedded ones), it is
	  necessary or convenient to provide some or all of the
	  kernel boot arguments with the kernel itself (that is,
	  to not rely on the boot loader to provide them.)

	  To compile command line arguments into the kernel,
	  set this option to 'Y', then fill in the
2340
	  boot arguments in CONFIG_CMDLINE.
2341 2342 2343 2344 2345 2346 2347 2348

	  Systems with fully functional boot loaders (i.e. non-embedded)
	  should leave this option set to 'N'.

config CMDLINE
	string "Built-in kernel command string"
	depends on CMDLINE_BOOL
	default ""
2349
	help
2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363
	  Enter arguments here that should be compiled into the kernel
	  image and used at boot time.  If the boot loader provides a
	  command line at boot time, it is appended to this string to
	  form the full kernel command line, when the system boots.

	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
	  change this behavior.

	  In most cases, the command line (whether built-in or provided
	  by the boot loader) should specify the device for the root
	  file system.

config CMDLINE_OVERRIDE
	bool "Built-in command line overrides boot loader arguments"
2364
	depends on CMDLINE_BOOL && CMDLINE != ""
2365
	help
2366 2367 2368 2369 2370 2371
	  Set this option to 'Y' to have the kernel ignore the boot loader
	  command line, and use ONLY the built-in command line.

	  This is used to work around broken boot loaders.  This should
	  be set to 'N' under normal conditions.

2372 2373 2374
config MODIFY_LDT_SYSCALL
	bool "Enable the LDT (local descriptor table)" if EXPERT
	default y
2375
	help
2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387
	  Linux can allow user programs to install a per-process x86
	  Local Descriptor Table (LDT) using the modify_ldt(2) system
	  call.  This is required to run 16-bit or segmented code such as
	  DOSEMU or some Wine programs.  It is also used by some very old
	  threading libraries.

	  Enabling this feature adds a small amount of overhead to
	  context switches and increases the low-level kernel attack
	  surface.  Disabling it removes the modify_ldt(2) system call.

	  Saying 'N' here may make sense for embedded or server kernels.

2388 2389
source "kernel/livepatch/Kconfig"

2390 2391
endmenu

2392 2393 2394 2395
config ARCH_HAS_ADD_PAGES
	def_bool y
	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG

2396 2397 2398
config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
	def_bool y

2399
config USE_PERCPU_NUMA_NODE_ID
2400
	def_bool y
2401 2402
	depends on NUMA

2403
menu "Power management and ACPI options"
2404 2405

config ARCH_HIBERNATION_HEADER
2406
	def_bool y
2407
	depends on HIBERNATION
2408 2409 2410 2411 2412

source "kernel/power/Kconfig"

source "drivers/acpi/Kconfig"

2413
config X86_APM_BOOT
J
Jan Beulich 已提交
2414
	def_bool y
2415
	depends on APM
2416

2417 2418
menuconfig APM
	tristate "APM (Advanced Power Management) BIOS support"
2419
	depends on X86_32 && PM_SLEEP
2420
	help
2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434
	  APM is a BIOS specification for saving power using several different
	  techniques. This is mostly useful for battery powered laptops with
	  APM compliant BIOSes. If you say Y here, the system time will be
	  reset after a RESUME operation, the /proc/apm device will provide
	  battery status information, and user-space programs will receive
	  notification of APM "events" (e.g. battery status change).

	  If you select "Y" here, you can disable actual use of the APM
	  BIOS by passing the "apm=off" option to the kernel at boot time.

	  Note that the APM support is almost completely disabled for
	  machines with more than one CPU.

	  In order to use APM, you will need supporting software. For location
2435
	  and more information, read <file:Documentation/power/apm-acpi.rst>
2436
	  and the Battery Powered Linux mini-HOWTO, available from
2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479
	  <http://www.tldp.org/docs.html#howto>.

	  This driver does not spin down disk drives (see the hdparm(8)
	  manpage ("man 8 hdparm") for that), and it doesn't turn off
	  VESA-compliant "green" monitors.

	  This driver does not support the TI 4000M TravelMate and the ACER
	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
	  desktop machines also don't have compliant BIOSes, and this driver
	  may cause those machines to panic during the boot phase.

	  Generally, if you don't have a battery in your machine, there isn't
	  much point in using this driver and you should say N. If you get
	  random kernel OOPSes or reboots that don't seem to be related to
	  anything, try disabling/enabling this option (or disabling/enabling
	  APM in your BIOS).

	  Some other things you should try when experiencing seemingly random,
	  "weird" problems:

	  1) make sure that you have enough swap space and that it is
	  enabled.
	  2) pass the "no-hlt" option to the kernel
	  3) switch on floating point emulation in the kernel and pass
	  the "no387" option to the kernel
	  4) pass the "floppy=nodma" option to the kernel
	  5) pass the "mem=4M" option to the kernel (thereby disabling
	  all but the first 4 MB of RAM)
	  6) make sure that the CPU is not over clocked.
	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
	  8) disable the cache from your BIOS settings
	  9) install a fan for the video card or exchange video RAM
	  10) install a better fan for the CPU
	  11) exchange RAM chips
	  12) exchange the motherboard.

	  To compile this driver as a module, choose M here: the
	  module will be called apm.

if APM

config APM_IGNORE_USER_SUSPEND
	bool "Ignore USER SUSPEND"
2480
	help
2481 2482 2483 2484 2485 2486
	  This option will ignore USER SUSPEND requests. On machines with a
	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
	  series notebooks, it is necessary to say Y because of a BIOS bug.

config APM_DO_ENABLE
	bool "Enable PM at boot time"
2487
	help
2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502
	  Enable APM features at boot time. From page 36 of the APM BIOS
	  specification: "When disabled, the APM BIOS does not automatically
	  power manage devices, enter the Standby State, enter the Suspend
	  State, or take power saving steps in response to CPU Idle calls."
	  This driver will make CPU Idle calls when Linux is idle (unless this
	  feature is turned off -- see "Do CPU IDLE calls", below). This
	  should always save battery power, but more complicated APM features
	  will be dependent on your BIOS implementation. You may need to turn
	  this option off if your computer hangs at boot time when using APM
	  support, or if it beeps continuously instead of suspending. Turn
	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
	  T400CDT. This is off by default since most machines do fine without
	  this feature.

config APM_CPU_IDLE
2503
	depends on CPU_IDLE
2504
	bool "Make CPU Idle calls when idle"
2505
	help
2506 2507 2508 2509 2510 2511 2512 2513 2514 2515
	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
	  On some machines, this can activate improved power savings, such as
	  a slowed CPU clock rate, when the machine is idle. These idle calls
	  are made after the idle loop has run for some length of time (e.g.,
	  333 mS). On some machines, this will cause a hang at boot time or
	  whenever the CPU becomes idle. (On machines with more than one CPU,
	  this option does nothing.)

config APM_DISPLAY_BLANK
	bool "Enable console blanking using APM"
2516
	help
2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528
	  Enable console blanking using the APM. Some laptops can use this to
	  turn off the LCD backlight when the screen blanker of the Linux
	  virtual console blanks the screen. Note that this is only used by
	  the virtual console screen blanker, and won't turn off the backlight
	  when using the X Window system. This also doesn't have anything to
	  do with your VESA-compliant power-saving monitor. Further, this
	  option doesn't work for all laptops -- it might not turn off your
	  backlight at all, or it might print a lot of errors to the console,
	  especially if you are using gpm.

config APM_ALLOW_INTS
	bool "Allow interrupts during APM BIOS calls"
2529
	help
2530 2531 2532 2533 2534 2535 2536 2537 2538
	  Normally we disable external interrupts while we are making calls to
	  the APM BIOS as a measure to lessen the effects of a badly behaving
	  BIOS implementation.  The BIOS should reenable interrupts if it
	  needs to.  Unfortunately, some BIOSes do not -- especially those in
	  many of the newer IBM Thinkpads.  If you experience hangs when you
	  suspend, try setting this to Y.  Otherwise, say N.

endif # APM

2539
source "drivers/cpufreq/Kconfig"
2540 2541 2542

source "drivers/cpuidle/Kconfig"

A
Andy Henroid 已提交
2543 2544
source "drivers/idle/Kconfig"

2545 2546 2547 2548 2549 2550 2551
endmenu


menu "Bus options (PCI etc.)"

choice
	prompt "PCI access mode"
2552
	depends on X86_32 && PCI
2553
	default PCI_GOANY
2554
	help
2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577
	  On PCI systems, the BIOS can be used to detect the PCI devices and
	  determine their configuration. However, some old PCI motherboards
	  have BIOS bugs and may crash if this is done. Also, some embedded
	  PCI-based systems don't have any BIOS at all. Linux can also try to
	  detect the PCI hardware directly without using the BIOS.

	  With this option, you can specify how Linux should detect the
	  PCI devices. If you choose "BIOS", the BIOS will be used,
	  if you choose "Direct", the BIOS won't be used, and if you
	  choose "MMConfig", then PCI Express MMCONFIG will be used.
	  If you choose "Any", the kernel will try MMCONFIG, then the
	  direct access method and falls back to the BIOS if that doesn't
	  work. If unsure, go with the default, which is "Any".

config PCI_GOBIOS
	bool "BIOS"

config PCI_GOMMCONFIG
	bool "MMConfig"

config PCI_GODIRECT
	bool "Direct"

2578
config PCI_GOOLPC
2579
	bool "OLPC XO-1"
2580 2581
	depends on OLPC

2582 2583 2584
config PCI_GOANY
	bool "Any"

2585 2586 2587
endchoice

config PCI_BIOS
2588
	def_bool y
2589
	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2590 2591 2592

# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
config PCI_DIRECT
2593
	def_bool y
2594
	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2595 2596

config PCI_MMCONFIG
2597 2598
	bool "Support mmconfig PCI config space access" if X86_64
	default y
2599
	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2600
	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2601

2602
config PCI_OLPC
2603 2604
	def_bool y
	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2605

2606 2607 2608 2609 2610
config PCI_XEN
	def_bool y
	depends on PCI && XEN
	select SWIOTLB_XEN

2611 2612 2613
config MMCONF_FAM10H
	def_bool y
	depends on X86_64 && PCI_MMCONFIG && ACPI
2614

2615
config PCI_CNB20LE_QUIRK
2616
	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2617
	depends on PCI
2618 2619 2620 2621 2622
	help
	  Read the PCI windows out of the CNB20LE host bridge. This allows
	  PCI hotplug to work on systems with the CNB20LE chipset which do
	  not have ACPI.

2623 2624 2625 2626 2627
	  There's no public spec for this chipset, and this functionality
	  is known to be incomplete.

	  You should say N unless you know you need this.

2628
config ISA_BUS
2629
	bool "ISA bus support on modern systems" if EXPERT
2630
	help
2631 2632 2633 2634 2635
	  Expose ISA bus device drivers and options available for selection and
	  configuration. Enable this option if your target machine has an ISA
	  bus. ISA is an older system, displaced by PCI and newer bus
	  architectures -- if your target machine is modern, it probably does
	  not have an ISA bus.
2636 2637 2638

	  If unsure, say N.

2639
# x86_64 have no ISA slots, but can have ISA-style DMA.
2640
config ISA_DMA_API
2641 2642 2643 2644 2645
	bool "ISA-style DMA support" if (X86_64 && EXPERT)
	default y
	help
	  Enables ISA-style DMA support for devices requiring such controllers.
	  If unsure, say Y.
2646

2647 2648
if X86_32

2649 2650
config ISA
	bool "ISA support"
2651
	help
2652 2653 2654 2655 2656 2657 2658 2659
	  Find out whether you have ISA slots on your motherboard.  ISA is the
	  name of a bus system, i.e. the way the CPU talks to the other stuff
	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
	  newer boards don't support it.  If you have ISA, say Y, otherwise N.

config SCx200
	tristate "NatSemi SCx200 support"
2660
	help
2661 2662 2663 2664 2665 2666 2667 2668 2669
	  This provides basic support for National Semiconductor's
	  (now AMD's) Geode processors.  The driver probes for the
	  PCI-IDs of several on-chip devices, so its a good dependency
	  for other scx200_* drivers.

	  If compiled as a module, the driver is named scx200.

config SCx200HR_TIMER
	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
J
John Stultz 已提交
2670
	depends on SCx200
2671
	default y
2672
	help
2673 2674 2675 2676 2677 2678
	  This driver provides a clocksource built upon the on-chip
	  27MHz high-resolution timer.  Its also a workaround for
	  NSC Geode SC-1100's buggy TSC, which loses time when the
	  processor goes idle (as is done by the scheduler).  The
	  other workaround is idle=poll boot option.

2679 2680
config OLPC
	bool "One Laptop Per Child support"
2681
	depends on !X86_PAE
2682
	select GPIOLIB
2683
	select OF
2684
	select OF_PROMTREE
2685
	select IRQ_DOMAIN
2686
	select OLPC_EC
2687
	help
2688 2689 2690
	  Add support for detecting the unique features of the OLPC
	  XO hardware.

2691 2692
config OLPC_XO1_PM
	bool "OLPC XO-1 Power Management"
2693
	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2694
	help
2695
	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2696

D
Daniel Drake 已提交
2697 2698 2699
config OLPC_XO1_RTC
	bool "OLPC XO-1 Real Time Clock"
	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2700
	help
D
Daniel Drake 已提交
2701 2702 2703
	  Add support for the XO-1 real time clock, which can be used as a
	  programmable wakeup source.

2704 2705
config OLPC_XO1_SCI
	bool "OLPC XO-1 SCI extras"
2706
	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2707
	depends on INPUT=y
2708
	select POWER_SUPPLY
2709
	help
2710
	  Add support for SCI-based features of the OLPC XO-1 laptop:
2711
	   - EC-driven system wakeups
2712
	   - Power button
2713
	   - Ebook switch
2714
	   - Lid switch
2715 2716
	   - AC adapter status updates
	   - Battery status updates
2717

D
Daniel Drake 已提交
2718 2719
config OLPC_XO15_SCI
	bool "OLPC XO-1.5 SCI extras"
2720 2721
	depends on OLPC && ACPI
	select POWER_SUPPLY
2722
	help
D
Daniel Drake 已提交
2723 2724 2725 2726
	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
	   - EC-driven system wakeups
	   - AC adapter status updates
	   - Battery status updates
2727

2728 2729 2730
config ALIX
	bool "PCEngines ALIX System Support (LED setup)"
	select GPIOLIB
2731
	help
2732 2733 2734 2735 2736 2737 2738 2739 2740 2741
	  This option enables system support for the PCEngines ALIX.
	  At present this just sets up LEDs for GPIO control on
	  ALIX2/3/6 boards.  However, other system specific setup should
	  get added here.

	  Note: You must still enable the drivers for GPIO and LED support
	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs

	  Note: You have to set alix.force=1 for boards with Award BIOS.

2742 2743 2744
config NET5501
	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
	select GPIOLIB
2745
	help
2746 2747
	  This option enables system support for the Soekris Engineering net5501.

2748 2749 2750 2751
config GEOS
	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
	select GPIOLIB
	depends on DMI
2752
	help
2753 2754
	  This option enables system support for the Traverse Technologies GEOS.

2755 2756 2757 2758 2759 2760
config TS5500
	bool "Technologic Systems TS-5500 platform support"
	depends on MELAN
	select CHECK_SIGNATURE
	select NEW_LEDS
	select LEDS_CLASS
2761
	help
2762 2763
	  This option enables system support for the Technologic Systems TS-5500.

2764 2765
endif # X86_32

2766
config AMD_NB
2767
	def_bool y
2768
	depends on CPU_SUP_AMD && PCI
2769

2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780
config X86_SYSFB
	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
	help
	  Firmwares often provide initial graphics framebuffers so the BIOS,
	  bootloader or kernel can show basic video-output during boot for
	  user-guidance and debugging. Historically, x86 used the VESA BIOS
	  Extensions and EFI-framebuffers for this, which are mostly limited
	  to x86.
	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
	  framebuffers so the new generic system-framebuffer drivers can be
	  used on x86. If the framebuffer is not compatible with the generic
N
Nikolas Nyby 已提交
2781
	  modes, it is advertised as fallback platform framebuffer so legacy
2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795
	  drivers like efifb, vesafb and uvesafb can pick it up.
	  If this option is not selected, all system framebuffers are always
	  marked as fallback platform framebuffers as usual.

	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
	  not be able to pick up generic system framebuffers if this option
	  is selected. You are highly encouraged to enable simplefb as
	  replacement if you select this option. simplefb can correctly deal
	  with generic system framebuffers. But you should still keep vesafb
	  and others enabled as fallback if a system framebuffer is
	  incompatible with simplefb.

	  If unsure, say Y.

2796 2797 2798
endmenu


2799
menu "Binary Emulations"
2800 2801 2802 2803

config IA32_EMULATION
	bool "IA32 Emulation"
	depends on X86_64
2804
	select ARCH_WANT_OLD_COMPAT_IPC
2805
	select BINFMT_ELF
2806
	select COMPAT_OLD_SIGACTION
2807
	help
H
H. J. Lu 已提交
2808 2809 2810
	  Include code to run legacy 32-bit programs under a
	  64-bit kernel. You should likely turn this on, unless you're
	  100% sure that you don't have any 32-bit programs left.
2811 2812

config IA32_AOUT
I
Ingo Molnar 已提交
2813 2814
	tristate "IA32 a.out support"
	depends on IA32_EMULATION
B
Borislav Petkov 已提交
2815
	depends on BROKEN
2816
	help
I
Ingo Molnar 已提交
2817
	  Support old a.out binaries in the 32bit emulation.
2818

2819
config X86_X32
2820
	bool "x32 ABI for 64-bit mode"
2821
	depends on X86_64
2822
	help
H
H. J. Lu 已提交
2823 2824 2825 2826 2827 2828 2829 2830 2831
	  Include code to run binaries for the x32 native 32-bit ABI
	  for 64-bit processors.  An x32 process gets access to the
	  full 64-bit register file and wide data path while leaving
	  pointers at 32 bits for smaller memory footprint.

	  You will need a recent binutils (2.22 or later) with
	  elf32_x86_64 support enabled to compile a kernel with this
	  option set.

2832 2833 2834 2835 2836 2837
config COMPAT_32
	def_bool y
	depends on IA32_EMULATION || X86_32
	select HAVE_UID16
	select OLD_SIGSUSPEND3

2838
config COMPAT
2839
	def_bool y
2840
	depends on IA32_EMULATION || X86_X32
2841

2842
if COMPAT
2843
config COMPAT_FOR_U64_ALIGNMENT
2844
	def_bool y
2845 2846

config SYSVIPC_COMPAT
2847
	def_bool y
2848 2849
	depends on SYSVIPC
endif
2850

2851 2852 2853
endmenu


K
Keith Packard 已提交
2854 2855 2856 2857
config HAVE_ATOMIC_IOMAP
	def_bool y
	depends on X86_32

2858 2859
source "drivers/firmware/Kconfig"

2860
source "arch/x86/kvm/Kconfig"
2861 2862

source "arch/x86/Kconfig.assembler"