xref: /linux/arch/x86/Kconfig (revision 7fec07fd217800c5174f51d8869518807e9aa144)
1b2441318SGreg Kroah-Hartman# SPDX-License-Identifier: GPL-2.0
2daa93fabSSam Ravnborg# Select 32 or 64 bit
3daa93fabSSam Ravnborgconfig 64BIT
4104daea1SMasahiro Yamada	bool "64-bit kernel" if "$(ARCH)" = "x86"
5104daea1SMasahiro Yamada	default "$(ARCH)" != "i386"
6a7f7f624SMasahiro Yamada	help
7daa93fabSSam Ravnborg	  Say yes to build a 64-bit kernel - formerly known as x86_64
8daa93fabSSam Ravnborg	  Say no to build a 32-bit kernel - formerly known as i386
9daa93fabSSam Ravnborg
10daa93fabSSam Ravnborgconfig X86_32
113120e25eSJan Beulich	def_bool y
123120e25eSJan Beulich	depends on !64BIT
13341c787eSIngo Molnar	# Options that are inherently 32-bit kernel only:
14341c787eSIngo Molnar	select ARCH_WANT_IPC_PARSE_VERSION
15341c787eSIngo Molnar	select CLKSRC_I8253
16341c787eSIngo Molnar	select CLONE_BACKWARDS
17157e118bSThomas Gleixner	select GENERIC_VDSO_32
18117ed454SThomas Gleixner	select HAVE_DEBUG_STACKOVERFLOW
19157e118bSThomas Gleixner	select KMAP_LOCAL
20341c787eSIngo Molnar	select MODULES_USE_ELF_REL
21341c787eSIngo Molnar	select OLD_SIGACTION
222ca408d9SBrian Gerst	select ARCH_SPLIT_ARG64
23daa93fabSSam Ravnborg
24daa93fabSSam Ravnborgconfig X86_64
253120e25eSJan Beulich	def_bool y
263120e25eSJan Beulich	depends on 64BIT
27d94e0685SIngo Molnar	# Options that are inherently 64-bit kernel only:
284eb0716eSAlexandre Ghiti	select ARCH_HAS_GIGANTIC_PAGE
29c12d3362SArd Biesheuvel	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
300bff0aaeSSuren Baghdasaryan	select ARCH_SUPPORTS_PER_VMA_LOCK
31d94e0685SIngo Molnar	select HAVE_ARCH_SOFT_DIRTY
32d94e0685SIngo Molnar	select MODULES_USE_ELF_RELA
33f616ab59SChristoph Hellwig	select NEED_DMA_MAP_STATE
3409230cbcSChristoph Hellwig	select SWIOTLB
357facdc42SAl Viro	select ARCH_HAS_ELFCORE_COMPAT
3663703f37SKefeng Wang	select ZONE_DMA32
371032c0baSSam Ravnborg
38518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE
39518049d9SSteven Rostedt (VMware)	def_bool y
40518049d9SSteven Rostedt (VMware)	depends on X86_32
41518049d9SSteven Rostedt (VMware)	depends on FUNCTION_TRACER
42518049d9SSteven Rostedt (VMware)	select DYNAMIC_FTRACE
43518049d9SSteven Rostedt (VMware)	help
44518049d9SSteven Rostedt (VMware)	  We keep the static function tracing (!DYNAMIC_FTRACE) around
45518049d9SSteven Rostedt (VMware)	  in order to test the non static function tracing in the
46518049d9SSteven Rostedt (VMware)	  generic code, as other architectures still use it. But we
47518049d9SSteven Rostedt (VMware)	  only need to keep it around for x86_64. No need to keep it
48518049d9SSteven Rostedt (VMware)	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
49d94e0685SIngo Molnar#
50d94e0685SIngo Molnar# Arch settings
51d94e0685SIngo Molnar#
52d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be
53d94e0685SIngo Molnar#   ported to 32-bit as well. )
54d94e0685SIngo Molnar#
558d5fffb9SSam Ravnborgconfig X86
563c2362e6SHarvey Harrison	def_bool y
57c763ea26SIngo Molnar	#
58c763ea26SIngo Molnar	# Note: keep this list sorted alphabetically
59c763ea26SIngo Molnar	#
606471b825SIngo Molnar	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
616e0a0ea1SGraeme Gregory	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
62a02f66bbSJames Morse	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
63942fa985SYury Norov	select ARCH_32BIT_OFF_T			if X86_32
642a21ad57SThomas Gleixner	select ARCH_CLOCKSOURCE_INIT
651f6d3a8fSMasami Hiramatsu	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
661e866974SAnshuman Khandual	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
675c11f00bSDavid Hildenbrand	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
6891024b3cSAnshuman Khandual	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
69cebc774fSAnshuman Khandual	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
701e866974SAnshuman Khandual	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
7191dda51aSAleksey Makarov	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
72c2280be8SAnshuman Khandual	select ARCH_HAS_CACHE_LINE_SIZE
731156b441SDavidlohr Bueso	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
747c7077a7SThomas Gleixner	select ARCH_HAS_CPU_FINALIZE_INIT
758f23f5dbSJason Gunthorpe	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
762792d84eSKees Cook	select ARCH_HAS_CURRENT_STACK_POINTER
77fa5b6ec9SLaura Abbott	select ARCH_HAS_DEBUG_VIRTUAL
78399145f9SAnshuman Khandual	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
7921266be9SDan Williams	select ARCH_HAS_DEVMEM_IS_ALLOWED
80b1a57bbfSDouglas Anderson	select ARCH_HAS_EARLY_DEBUG		if KGDB
816471b825SIngo Molnar	select ARCH_HAS_ELF_RANDOMIZE
8272d93104SLinus Torvalds	select ARCH_HAS_FAST_MULTIPLIER
836974f0c4SDaniel Micay	select ARCH_HAS_FORTIFY_SOURCE
84957e3facSRiku Voipio	select ARCH_HAS_GCOV_PROFILE_ALL
85bece04b5SMarco Elver	select ARCH_HAS_KCOV			if X86_64
860c9c1d56SThiago Jung Bauermann	select ARCH_HAS_MEM_ENCRYPT
8710bcc80eSMathieu Desnoyers	select ARCH_HAS_MEMBARRIER_SYNC_CORE
8849f88c70SPaul E. McKenney	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
890ebeea8cSDaniel Borkmann	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
90c763ea26SIngo Molnar	select ARCH_HAS_PMEM_API		if X86_64
9117596731SRobin Murphy	select ARCH_HAS_PTE_DEVMAP		if X86_64
923010a5eaSLaurent Dufour	select ARCH_HAS_PTE_SPECIAL
9371ce1ab5SKinsey Ho	select ARCH_HAS_HW_PTE_YOUNG
94eed9a328SYu Zhao	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
950aed55afSDan Williams	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
96ec6347bbSDan Williams	select ARCH_HAS_COPY_MC			if X86_64
97d2852a22SDaniel Borkmann	select ARCH_HAS_SET_MEMORY
98d253ca0cSRick Edgecombe	select ARCH_HAS_SET_DIRECT_MAP
99ad21fc4fSLaura Abbott	select ARCH_HAS_STRICT_KERNEL_RWX
100ad21fc4fSLaura Abbott	select ARCH_HAS_STRICT_MODULE_RWX
101ac1ab12aSMathieu Desnoyers	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
10225c619e5SBrian Gerst	select ARCH_HAS_SYSCALL_WRAPPER
103918327e9SKees Cook	select ARCH_HAS_UBSAN
1047e01ccb4SZong Li	select ARCH_HAS_DEBUG_WX
10563703f37SKefeng Wang	select ARCH_HAS_ZONE_DMA_SET if EXPERT
1066471b825SIngo Molnar	select ARCH_HAVE_NMI_SAFE_CMPXCHG
10704d5ea46SAneesh Kumar K.V	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
1086471b825SIngo Molnar	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
10977fbbc81SMark Salter	select ARCH_MIGHT_HAVE_PC_PARPORT
1105e2c18c0SMark Salter	select ARCH_MIGHT_HAVE_PC_SERIO
1113599fe12SThomas Gleixner	select ARCH_STACKWALK
1122c870e61SArnd Bergmann	select ARCH_SUPPORTS_ACPI
1136471b825SIngo Molnar	select ARCH_SUPPORTS_ATOMIC_RMW
1145d6ad668SMike Rapoport	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
115d283d422SPasha Tatashin	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
1166471b825SIngo Molnar	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
11714df3267SThomas Gleixner	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
1183c516f89SSami Tolvanen	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
1193c516f89SSami Tolvanen	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
120583bfd48SNathan Chancellor	select ARCH_SUPPORTS_LTO_CLANG
121583bfd48SNathan Chancellor	select ARCH_SUPPORTS_LTO_CLANG_THIN
1226471b825SIngo Molnar	select ARCH_USE_BUILTIN_BSWAP
123a432b7c0SUros Bizjak	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CMPXCHG64
124dce44566SAnshuman Khandual	select ARCH_USE_MEMTEST
1256471b825SIngo Molnar	select ARCH_USE_QUEUED_RWLOCKS
1266471b825SIngo Molnar	select ARCH_USE_QUEUED_SPINLOCKS
1272ce0d7f9SMark Brown	select ARCH_USE_SYM_ANNOTATIONS
128ce4a4e56SAndy Lutomirski	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
12981c22041SDaniel Borkmann	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
130c763ea26SIngo Molnar	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
13151c2ee6dSNick Desaulniers	select ARCH_WANTS_NO_INSTR
13207431506SAnshuman Khandual	select ARCH_WANT_GENERAL_HUGETLB
1333876d4a3SAlexandre Ghiti	select ARCH_WANT_HUGE_PMD_SHARE
13459612b24SNathan Chancellor	select ARCH_WANT_LD_ORPHAN_WARN
1350b6f1582SAneesh Kumar K.V	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
1360b6f1582SAneesh Kumar K.V	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
13738d8b4e6SHuang Ying	select ARCH_WANTS_THP_SWAP		if X86_64
138b5f06f64SBalbir Singh	select ARCH_HAS_PARANOID_L1D_FLUSH
13910916706SShile Zhang	select BUILDTIME_TABLE_SORT
1406471b825SIngo Molnar	select CLKEVT_I8253
1416471b825SIngo Molnar	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
1426471b825SIngo Molnar	select CLOCKSOURCE_WATCHDOG
1437cf8f44aSAlexander Potapenko	# Word-size accesses may read uninitialized data past the trailing \0
1447cf8f44aSAlexander Potapenko	# in strings and cause false KMSAN reports.
1457cf8f44aSAlexander Potapenko	select DCACHE_WORD_ACCESS		if !KMSAN
1463aac3ebeSThomas Gleixner	select DYNAMIC_SIGFRAME
14745471cd9SLinus Torvalds	select EDAC_ATOMIC_SCRUB
14845471cd9SLinus Torvalds	select EDAC_SUPPORT
1496471b825SIngo Molnar	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
150cb81deefSThomas Gleixner	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
1516471b825SIngo Molnar	select GENERIC_CLOCKEVENTS_MIN_ADJUST
1526471b825SIngo Molnar	select GENERIC_CMOS_UPDATE
1536471b825SIngo Molnar	select GENERIC_CPU_AUTOPROBE
1545b95f94cSJames Morse	select GENERIC_CPU_DEVICES
15561dc0f55SThomas Gleixner	select GENERIC_CPU_VULNERABILITIES
1566471b825SIngo Molnar	select GENERIC_EARLY_IOREMAP
15727d6b4d1SThomas Gleixner	select GENERIC_ENTRY
1586471b825SIngo Molnar	select GENERIC_IOMAP
159c7d6c9ddSThomas Gleixner	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
1600fa115daSThomas Gleixner	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
161ad7a929fSThomas Gleixner	select GENERIC_IRQ_MIGRATION		if SMP
1626471b825SIngo Molnar	select GENERIC_IRQ_PROBE
163c201c917SThomas Gleixner	select GENERIC_IRQ_RESERVATION_MODE
1646471b825SIngo Molnar	select GENERIC_IRQ_SHOW
1656471b825SIngo Molnar	select GENERIC_PENDING_IRQ		if SMP
1662ae27137SSteven Price	select GENERIC_PTDUMP
1676471b825SIngo Molnar	select GENERIC_SMP_IDLE_THREAD
1686471b825SIngo Molnar	select GENERIC_TIME_VSYSCALL
1697ac87074SVincenzo Frascino	select GENERIC_GETTIMEOFDAY
170550a77a7SDmitry Safonov	select GENERIC_VDSO_TIME_NS
1716ca297d4SPeter Zijlstra	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
17217e5888eSHans de Goede	select HARDIRQS_SW_RESEND
1737edaeb68SThomas Gleixner	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
174fcbfe812SNiklas Schnelle	select HAS_IOPORT
1756471b825SIngo Molnar	select HAVE_ACPI_APEI			if ACPI
1766471b825SIngo Molnar	select HAVE_ACPI_APEI_NMI		if ACPI
1772a19be61SVlastimil Babka	select HAVE_ALIGNED_STRUCT_PAGE
1786471b825SIngo Molnar	select HAVE_ARCH_AUDITSYSCALL
1796471b825SIngo Molnar	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
180eed1fceeSSong Liu	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
1816471b825SIngo Molnar	select HAVE_ARCH_JUMP_LABEL
182b34006c4SArd Biesheuvel	select HAVE_ARCH_JUMP_LABEL_RELATIVE
183d17a1d97SAndrey Ryabinin	select HAVE_ARCH_KASAN			if X86_64
1840609ae01SDaniel Axtens	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
1851dc0da6eSAlexander Potapenko	select HAVE_ARCH_KFENCE
1864ca8cc8dSAlexander Potapenko	select HAVE_ARCH_KMSAN			if X86_64
1876471b825SIngo Molnar	select HAVE_ARCH_KGDB
1889e08f57dSDaniel Cashman	select HAVE_ARCH_MMAP_RND_BITS		if MMU
1899e08f57dSDaniel Cashman	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
1901b028f78SDmitry Safonov	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
191271ca788SArd Biesheuvel	select HAVE_ARCH_PREL32_RELOCATIONS
1926471b825SIngo Molnar	select HAVE_ARCH_SECCOMP_FILTER
193f7d83c1cSKees Cook	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
194afaef01cSAlexander Popov	select HAVE_ARCH_STACKLEAK
1956471b825SIngo Molnar	select HAVE_ARCH_TRACEHOOK
1966471b825SIngo Molnar	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
197a00cc7d9SMatthew Wilcox	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
198b64d8d1eSPeter Xu	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
1997677f7fdSAxel Rasmussen	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
200e37e43a4SAndy Lutomirski	select HAVE_ARCH_VMAP_STACK		if X86_64
201fe950f60SKees Cook	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
202c763ea26SIngo Molnar	select HAVE_ARCH_WITHIN_STACK_FRAMES
2032ff2b7ecSMasahiro Yamada	select HAVE_ASM_MODVERSIONS
2046471b825SIngo Molnar	select HAVE_CMPXCHG_DOUBLE
2056471b825SIngo Molnar	select HAVE_CMPXCHG_LOCAL
20624a9c541SFrederic Weisbecker	select HAVE_CONTEXT_TRACKING_USER		if X86_64
20724a9c541SFrederic Weisbecker	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
2086471b825SIngo Molnar	select HAVE_C_RECORDMCOUNT
20903f16cd0SJosh Poimboeuf	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
210280981d6SSathvika Vasireddy	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
2114ed308c4SSteven Rostedt (Google)	select HAVE_BUILDTIME_MCOUNT_SORT
2126471b825SIngo Molnar	select HAVE_DEBUG_KMEMLEAK
2139c5a3621SAkinobu Mita	select HAVE_DMA_CONTIGUOUS
214677aa9f7SSteven Rostedt	select HAVE_DYNAMIC_FTRACE
21506aeaaeaSMasami Hiramatsu	select HAVE_DYNAMIC_FTRACE_WITH_REGS
21602a474caSSteven Rostedt (VMware)	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
217562955feSSteven Rostedt (VMware)	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
218c316eb44SHeiko Carstens	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
219503e4510SHeiko Carstens	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
22003f5781bSWang YanQing	select HAVE_EBPF_JIT
22158340a07SJohannes Berg	select HAVE_EFFICIENT_UNALIGNED_ACCESS
2226630a8e5SChristoph Hellwig	select HAVE_EISA
2235f56a5dfSJiri Slaby	select HAVE_EXIT_THREAD
22467a929e0SChristoph Hellwig	select HAVE_FAST_GUP
225644e0e8dSSteven Rostedt (VMware)	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
2266471b825SIngo Molnar	select HAVE_FTRACE_MCOUNT_RECORD
227d938ba17SDonglin Peng	select HAVE_FUNCTION_GRAPH_RETVAL	if HAVE_FUNCTION_GRAPH_TRACER
2284a30e4c9SSteven Rostedt (VMware)	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
2296471b825SIngo Molnar	select HAVE_FUNCTION_TRACER
2306b90bd4bSEmese Revfy	select HAVE_GCC_PLUGINS
2310067f129SK.Prasad	select HAVE_HW_BREAKPOINT
2326471b825SIngo Molnar	select HAVE_IOREMAP_PROT
233624db9eaSThomas Gleixner	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
2346471b825SIngo Molnar	select HAVE_IRQ_TIME_ACCOUNTING
2354ab7674fSJosh Poimboeuf	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
2366471b825SIngo Molnar	select HAVE_KERNEL_BZIP2
2376471b825SIngo Molnar	select HAVE_KERNEL_GZIP
2386471b825SIngo Molnar	select HAVE_KERNEL_LZ4
2396471b825SIngo Molnar	select HAVE_KERNEL_LZMA
2406471b825SIngo Molnar	select HAVE_KERNEL_LZO
2416471b825SIngo Molnar	select HAVE_KERNEL_XZ
242fb46d057SNick Terrell	select HAVE_KERNEL_ZSTD
2436471b825SIngo Molnar	select HAVE_KPROBES
2446471b825SIngo Molnar	select HAVE_KPROBES_ON_FTRACE
245540adea3SMasami Hiramatsu	select HAVE_FUNCTION_ERROR_INJECTION
2466471b825SIngo Molnar	select HAVE_KRETPROBES
247f3a112c0SMasami Hiramatsu	select HAVE_RETHOOK
2486471b825SIngo Molnar	select HAVE_LIVEPATCH			if X86_64
2490102752eSFrederic Weisbecker	select HAVE_MIXED_BREAKPOINTS_REGS
250ee9f8fceSJosh Poimboeuf	select HAVE_MOD_ARCH_SPECIFIC
2519f132f7eSJoel Fernandes (Google)	select HAVE_MOVE_PMD
252be37c98dSKalesh Singh	select HAVE_MOVE_PUD
25322102f45SJosh Poimboeuf	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
25442a0bb3fSPetr Mladek	select HAVE_NMI
255489e355bSJosh Poimboeuf	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
25603f16cd0SJosh Poimboeuf	select HAVE_OBJTOOL			if X86_64
2576471b825SIngo Molnar	select HAVE_OPTPROBES
2585394f1e9SArnd Bergmann	select HAVE_PAGE_SIZE_4KB
2596471b825SIngo Molnar	select HAVE_PCSPKR_PLATFORM
2606471b825SIngo Molnar	select HAVE_PERF_EVENTS
261c01d4323SFrederic Weisbecker	select HAVE_PERF_EVENTS_NMI
26292e5aae4SNicholas Piggin	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
263eb01d42aSChristoph Hellwig	select HAVE_PCI
264c5e63197SJiri Olsa	select HAVE_PERF_REGS
265c5ebcedbSJiri Olsa	select HAVE_PERF_USER_STACK_DUMP
266ff2e6d72SPeter Zijlstra	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
2671e9fdf21SPeter Zijlstra	select MMU_GATHER_MERGE_VMAS
26800998085SThomas Gleixner	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
2696471b825SIngo Molnar	select HAVE_REGS_AND_STACK_ACCESS_API
27003f16cd0SJosh Poimboeuf	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
2713c88ee19SMasami Hiramatsu	select HAVE_FUNCTION_ARG_ACCESS_API
2727ecd19cfSKefeng Wang	select HAVE_SETUP_PER_CPU_AREA
273cd1a41ceSThomas Gleixner	select HAVE_SOFTIRQ_ON_OWN_STACK
274d148eac0SMasahiro Yamada	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
27503f16cd0SJosh Poimboeuf	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
276e6d6c071SJosh Poimboeuf	select HAVE_STATIC_CALL
27703f16cd0SJosh Poimboeuf	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
27899cf983cSMark Rutland	select HAVE_PREEMPT_DYNAMIC_CALL
279d6761b8fSMathieu Desnoyers	select HAVE_RSEQ
28009498135SMiguel Ojeda	select HAVE_RUST			if X86_64
2816471b825SIngo Molnar	select HAVE_SYSCALL_TRACEPOINTS
2825f3da8c0SJosh Poimboeuf	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
2836471b825SIngo Molnar	select HAVE_UNSTABLE_SCHED_CLOCK
2847c68af6eSAvi Kivity	select HAVE_USER_RETURN_NOTIFIER
2857ac87074SVincenzo Frascino	select HAVE_GENERIC_VDSO
2860c7ffa32SThomas Gleixner	select HOTPLUG_PARALLEL			if SMP && X86_64
28705736e4aSThomas Gleixner	select HOTPLUG_SMT			if SMP
2880c7ffa32SThomas Gleixner	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
289c0185808SThomas Gleixner	select IRQ_FORCED_THREADING
290c2508ec5SLinus Torvalds	select LOCK_MM_AND_FIND_VMA
2917ecd19cfSKefeng Wang	select NEED_PER_CPU_EMBED_FIRST_CHUNK
2927ecd19cfSKefeng Wang	select NEED_PER_CPU_PAGE_FIRST_CHUNK
29386596f0aSChristoph Hellwig	select NEED_SG_DMA_LENGTH
2942eac9c2dSChristoph Hellwig	select PCI_DOMAINS			if PCI
295625210cfSSinan Kaya	select PCI_LOCKLESS_CONFIG		if PCI
2966471b825SIngo Molnar	select PERF_EVENTS
2973195ef59SPrarit Bhargava	select RTC_LIB
298d6faca40SArnd Bergmann	select RTC_MC146818_LIB
2996471b825SIngo Molnar	select SPARSE_IRQ
3006471b825SIngo Molnar	select SYSCTL_EXCEPTION_TRACE
30115f4eae7SAndy Lutomirski	select THREAD_INFO_IN_TASK
3024aae683fSMasahiro Yamada	select TRACE_IRQFLAGS_SUPPORT
3034510bffbSMark Rutland	select TRACE_IRQFLAGS_NMI_SUPPORT
3046471b825SIngo Molnar	select USER_STACKTRACE_SUPPORT
3053b02a051SIngo Molnar	select HAVE_ARCH_KCSAN			if X86_64
3060c608dadSAubrey Li	select PROC_PID_ARCH_STATUS		if PROC_FS
30750468e43SJarkko Sakkinen	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
308d49a0626SPeter Zijlstra	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
309d49a0626SPeter Zijlstra	select FUNCTION_ALIGNMENT_4B
3109e2b4be3SNayna Jain	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
311ceea991aSJiri Olsa	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
3127d8330a5SBalbir Singh
313ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER
3143120e25eSJan Beulich	def_bool y
3153120e25eSJan Beulich	depends on KPROBES || PERF_EVENTS || UPROBES
316ba7e4d13SIngo Molnar
31751b26adaSLinus Torvaldsconfig OUTPUT_FORMAT
31851b26adaSLinus Torvalds	string
31951b26adaSLinus Torvalds	default "elf32-i386" if X86_32
32051b26adaSLinus Torvalds	default "elf64-x86-64" if X86_64
32151b26adaSLinus Torvalds
3228d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT
3233c2362e6SHarvey Harrison	def_bool y
3248d5fffb9SSam Ravnborg
3258d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT
3263c2362e6SHarvey Harrison	def_bool y
3278d5fffb9SSam Ravnborg
3288d5fffb9SSam Ravnborgconfig MMU
3293c2362e6SHarvey Harrison	def_bool y
3308d5fffb9SSam Ravnborg
3319e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN
3329e08f57dSDaniel Cashman	default 28 if 64BIT
3339e08f57dSDaniel Cashman	default 8
3349e08f57dSDaniel Cashman
3359e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX
3369e08f57dSDaniel Cashman	default 32 if 64BIT
3379e08f57dSDaniel Cashman	default 16
3389e08f57dSDaniel Cashman
3399e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN
3409e08f57dSDaniel Cashman	default 8
3419e08f57dSDaniel Cashman
3429e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX
3439e08f57dSDaniel Cashman	default 16
3449e08f57dSDaniel Cashman
3458d5fffb9SSam Ravnborgconfig SBUS
3468d5fffb9SSam Ravnborg	bool
3478d5fffb9SSam Ravnborg
3488d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA
3493120e25eSJan Beulich	def_bool y
3503120e25eSJan Beulich	depends on ISA_DMA_API
3518d5fffb9SSam Ravnborg
352d911c67eSAlexander Potapenkoconfig GENERIC_CSUM
353d911c67eSAlexander Potapenko	bool
354d911c67eSAlexander Potapenko	default y if KMSAN || KASAN
355d911c67eSAlexander Potapenko
3568d5fffb9SSam Ravnborgconfig GENERIC_BUG
3573c2362e6SHarvey Harrison	def_bool y
3588d5fffb9SSam Ravnborg	depends on BUG
359b93a531eSJan Beulich	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
360b93a531eSJan Beulich
361b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS
362b93a531eSJan Beulich	bool
3638d5fffb9SSam Ravnborg
3648d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC
3653120e25eSJan Beulich	def_bool y
3663120e25eSJan Beulich	depends on ISA_DMA_API
3678d5fffb9SSam Ravnborg
3681032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY
3691032c0baSSam Ravnborg	def_bool y
3701032c0baSSam Ravnborg
3719a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX
3729a0b8415Svenkatesh.pallipadi@intel.com	def_bool y
3738d5fffb9SSam Ravnborg
374801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE
375801e4062SJohannes Berg	def_bool y
376801e4062SJohannes Berg
377f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE
378f4cb5700SJohannes Berg	def_bool y
379f4cb5700SJohannes Berg
3808d5fffb9SSam Ravnborgconfig AUDIT_ARCH
381e0fd24a3SJan Beulich	def_bool y if X86_64
3828d5fffb9SSam Ravnborg
383d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET
384d6f2d75aSAndrey Ryabinin	hex
385d6f2d75aSAndrey Ryabinin	depends on KASAN
386d6f2d75aSAndrey Ryabinin	default 0xdffffc0000000000
387d6f2d75aSAndrey Ryabinin
38869575d38SShane Wangconfig HAVE_INTEL_TXT
38969575d38SShane Wang	def_bool y
3906ea30386SKees Cook	depends on INTEL_IOMMU && ACPI
39169575d38SShane Wang
3926b0c3d44SSam Ravnborgconfig X86_64_SMP
3936b0c3d44SSam Ravnborg	def_bool y
3946b0c3d44SSam Ravnborg	depends on X86_64 && SMP
3956b0c3d44SSam Ravnborg
3962b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES
3972b144498SSrikar Dronamraju	def_bool y
3982b144498SSrikar Dronamraju
399d20642f0SRob Herringconfig FIX_EARLYCON_MEM
400d20642f0SRob Herring	def_bool y
401d20642f0SRob Herring
40294d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK
40394d49eb3SKirill A. Shutemov	bool
40494d49eb3SKirill A. Shutemov
40598233368SKirill A. Shutemovconfig PGTABLE_LEVELS
40698233368SKirill A. Shutemov	int
40777ef56e4SKirill A. Shutemov	default 5 if X86_5LEVEL
40898233368SKirill A. Shutemov	default 4 if X86_64
40998233368SKirill A. Shutemov	default 3 if X86_PAE
41098233368SKirill A. Shutemov	default 2
41198233368SKirill A. Shutemov
4122a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR
4132a61f474SMasahiro Yamada	bool
4141b866781SNathan Chancellor	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
4151b866781SNathan Chancellor	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
4162a61f474SMasahiro Yamada	help
4172a61f474SMasahiro Yamada	  We have to make sure stack protector is unconditionally disabled if
4183fb0fdb3SAndy Lutomirski	  the compiler produces broken code or if it does not let us control
4193fb0fdb3SAndy Lutomirski	  the segment on 32-bit kernels.
4202a61f474SMasahiro Yamada
421506f1d07SSam Ravnborgmenu "Processor type and features"
422506f1d07SSam Ravnborg
423506f1d07SSam Ravnborgconfig SMP
424506f1d07SSam Ravnborg	bool "Symmetric multi-processing support"
425a7f7f624SMasahiro Yamada	help
426506f1d07SSam Ravnborg	  This enables support for systems with more than one CPU. If you have
4274a474157SRobert Graffham	  a system with only one CPU, say N. If you have a system with more
4284a474157SRobert Graffham	  than one CPU, say Y.
429506f1d07SSam Ravnborg
4304a474157SRobert Graffham	  If you say N here, the kernel will run on uni- and multiprocessor
431506f1d07SSam Ravnborg	  machines, but will use only one CPU of a multiprocessor machine. If
432506f1d07SSam Ravnborg	  you say Y here, the kernel will run on many, but not all,
4334a474157SRobert Graffham	  uniprocessor machines. On a uniprocessor machine, the kernel
434506f1d07SSam Ravnborg	  will run faster if you say N here.
435506f1d07SSam Ravnborg
436506f1d07SSam Ravnborg	  Note that if you say Y here and choose architecture "586" or
437506f1d07SSam Ravnborg	  "Pentium" under "Processor family", the kernel will not work on 486
438506f1d07SSam Ravnborg	  architectures. Similarly, multiprocessor kernels for the "PPro"
439506f1d07SSam Ravnborg	  architecture may not work on all Pentium based boards.
440506f1d07SSam Ravnborg
441506f1d07SSam Ravnborg	  People using multiprocessor machines who say Y here should also say
442506f1d07SSam Ravnborg	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
443506f1d07SSam Ravnborg	  Management" code will be disabled if you say Y here.
444506f1d07SSam Ravnborg
445ff61f079SJonathan Corbet	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
4464f4cfa6cSMauro Carvalho Chehab	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
447506f1d07SSam Ravnborg	  <http://www.tldp.org/docs.html#howto>.
448506f1d07SSam Ravnborg
449506f1d07SSam Ravnborg	  If you don't know what to do here, say N.
450506f1d07SSam Ravnborg
45106cd9a7dSYinghai Luconfig X86_X2APIC
45206cd9a7dSYinghai Lu	bool "Support x2apic"
45319e3d60dSJan Kiszka	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
454a7f7f624SMasahiro Yamada	help
45506cd9a7dSYinghai Lu	  This enables x2apic support on CPUs that have this feature.
45606cd9a7dSYinghai Lu
45706cd9a7dSYinghai Lu	  This allows 32-bit apic IDs (so it can support very large systems),
45806cd9a7dSYinghai Lu	  and accesses the local apic via MSRs not via mmio.
45906cd9a7dSYinghai Lu
460b8d1d163SDaniel Sneddon	  Some Intel systems circa 2022 and later are locked into x2APIC mode
461b8d1d163SDaniel Sneddon	  and can not fall back to the legacy APIC modes if SGX or TDX are
462e3998434SMateusz Jończyk	  enabled in the BIOS. They will boot with very reduced functionality
463e3998434SMateusz Jończyk	  without enabling this option.
464b8d1d163SDaniel Sneddon
46506cd9a7dSYinghai Lu	  If you don't know what to do here, say N.
46606cd9a7dSYinghai Lu
467*7fec07fdSJacob Panconfig X86_POSTED_MSI
468*7fec07fdSJacob Pan	bool "Enable MSI and MSI-x delivery by posted interrupts"
469*7fec07fdSJacob Pan	depends on X86_64 && IRQ_REMAP
470*7fec07fdSJacob Pan	help
471*7fec07fdSJacob Pan	  This enables MSIs that are under interrupt remapping to be delivered as
472*7fec07fdSJacob Pan	  posted interrupts to the host kernel. Interrupt throughput can
473*7fec07fdSJacob Pan	  potentially be improved by coalescing CPU notifications during high
474*7fec07fdSJacob Pan	  frequency bursts.
475*7fec07fdSJacob Pan
476*7fec07fdSJacob Pan	  If you don't know what to do here, say N.
477*7fec07fdSJacob Pan
4786695c85bSYinghai Luconfig X86_MPPARSE
4794590d98fSAndy Shevchenko	bool "Enable MPS table" if ACPI
4807a527688SJan Beulich	default y
4815ab74722SIngo Molnar	depends on X86_LOCAL_APIC
482a7f7f624SMasahiro Yamada	help
4836695c85bSYinghai Lu	  For old smp systems that do not have proper acpi support. Newer systems
4846695c85bSYinghai Lu	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
4856695c85bSYinghai Lu
486e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL
487e6d42931SJohannes Weiner	bool "x86 CPU resource control support"
4886fe07ce3SBabu Moger	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
48959fe5a77SThomas Gleixner	select KERNFS
490e79f15a4SChen Yu	select PROC_CPU_RESCTRL		if PROC_FS
49178e99b4aSFenghua Yu	help
492e6d42931SJohannes Weiner	  Enable x86 CPU resource control support.
4936fe07ce3SBabu Moger
4946fe07ce3SBabu Moger	  Provide support for the allocation and monitoring of system resources
4956fe07ce3SBabu Moger	  usage by the CPU.
4966fe07ce3SBabu Moger
4976fe07ce3SBabu Moger	  Intel calls this Intel Resource Director Technology
4986fe07ce3SBabu Moger	  (Intel(R) RDT). More information about RDT can be found in the
4996fe07ce3SBabu Moger	  Intel x86 Architecture Software Developer Manual.
5006fe07ce3SBabu Moger
5016fe07ce3SBabu Moger	  AMD calls this AMD Platform Quality of Service (AMD QoS).
5026fe07ce3SBabu Moger	  More information about AMD QoS can be found in the AMD64 Technology
5036fe07ce3SBabu Moger	  Platform Quality of Service Extensions manual.
50478e99b4aSFenghua Yu
50578e99b4aSFenghua Yu	  Say N if unsure.
50678e99b4aSFenghua Yu
5072cce9591SH. Peter Anvin (Intel)config X86_FRED
5082cce9591SH. Peter Anvin (Intel)	bool "Flexible Return and Event Delivery"
5092cce9591SH. Peter Anvin (Intel)	depends on X86_64
5102cce9591SH. Peter Anvin (Intel)	help
5112cce9591SH. Peter Anvin (Intel)	  When enabled, try to use Flexible Return and Event Delivery
5122cce9591SH. Peter Anvin (Intel)	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
5132cce9591SH. Peter Anvin (Intel)	  ring transitions and exception/interrupt handling if the
5142cce9591SH. Peter Anvin (Intel)	  system supports.
5152cce9591SH. Peter Anvin (Intel)
5168425091fSRavikiran G Thirumalaiif X86_32
517a0d0bb4dSRandy Dunlapconfig X86_BIGSMP
518a0d0bb4dSRandy Dunlap	bool "Support for big SMP systems with more than 8 CPUs"
519a0d0bb4dSRandy Dunlap	depends on SMP
520a7f7f624SMasahiro Yamada	help
521e133f6eaSRandy Dunlap	  This option is needed for the systems that have more than 8 CPUs.
522a0d0bb4dSRandy Dunlap
523c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM
524c5c606d9SRavikiran G Thirumalai	bool "Support for extended (non-PC) x86 platforms"
525c5c606d9SRavikiran G Thirumalai	default y
526a7f7f624SMasahiro Yamada	help
52706ac8346SIngo Molnar	  If you disable this option then the kernel will only support
52806ac8346SIngo Molnar	  standard PC platforms. (which covers the vast majority of
52906ac8346SIngo Molnar	  systems out there.)
53006ac8346SIngo Molnar
5318425091fSRavikiran G Thirumalai	  If you enable this option then you'll be able to select support
5328425091fSRavikiran G Thirumalai	  for the following (non-PC) 32 bit x86 platforms:
533cb7b8023SBen Hutchings		Goldfish (Android emulator)
5348425091fSRavikiran G Thirumalai		AMD Elan
5358425091fSRavikiran G Thirumalai		RDC R-321x SoC
5368425091fSRavikiran G Thirumalai		SGI 320/540 (Visual Workstation)
53783125a3aSAlessandro Rubini		STA2X11-based (e.g. Northville)
5383f4110a4SThomas Gleixner		Moorestown MID devices
53906ac8346SIngo Molnar
54006ac8346SIngo Molnar	  If you have one of these systems, or if you want to build a
54106ac8346SIngo Molnar	  generic distribution kernel, say Y here - otherwise say N.
542758cd94aSJuerg Haefligerendif # X86_32
54306ac8346SIngo Molnar
5448425091fSRavikiran G Thirumalaiif X86_64
5458425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM
5468425091fSRavikiran G Thirumalai	bool "Support for extended (non-PC) x86 platforms"
5478425091fSRavikiran G Thirumalai	default y
548a7f7f624SMasahiro Yamada	help
5498425091fSRavikiran G Thirumalai	  If you disable this option then the kernel will only support
5508425091fSRavikiran G Thirumalai	  standard PC platforms. (which covers the vast majority of
5518425091fSRavikiran G Thirumalai	  systems out there.)
5528425091fSRavikiran G Thirumalai
5538425091fSRavikiran G Thirumalai	  If you enable this option then you'll be able to select support
5548425091fSRavikiran G Thirumalai	  for the following (non-PC) 64 bit x86 platforms:
55544b111b5SSteffen Persvold		Numascale NumaChip
5568425091fSRavikiran G Thirumalai		ScaleMP vSMP
5578425091fSRavikiran G Thirumalai		SGI Ultraviolet
5588425091fSRavikiran G Thirumalai
5598425091fSRavikiran G Thirumalai	  If you have one of these systems, or if you want to build a
5608425091fSRavikiran G Thirumalai	  generic distribution kernel, say Y here - otherwise say N.
561758cd94aSJuerg Haefligerendif # X86_64
562c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms
563c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions
56444b111b5SSteffen Persvoldconfig X86_NUMACHIP
56544b111b5SSteffen Persvold	bool "Numascale NumaChip"
56644b111b5SSteffen Persvold	depends on X86_64
56744b111b5SSteffen Persvold	depends on X86_EXTENDED_PLATFORM
56844b111b5SSteffen Persvold	depends on NUMA
56944b111b5SSteffen Persvold	depends on SMP
57044b111b5SSteffen Persvold	depends on X86_X2APIC
571f9726bfdSDaniel J Blueman	depends on PCI_MMCONFIG
572a7f7f624SMasahiro Yamada	help
57344b111b5SSteffen Persvold	  Adds support for Numascale NumaChip large-SMP systems. Needed to
57444b111b5SSteffen Persvold	  enable more than ~168 cores.
57544b111b5SSteffen Persvold	  If you don't have one of these, you should say N here.
57603b48632SNick Piggin
5776a48565eSIngo Molnarconfig X86_VSMP
578c5c606d9SRavikiran G Thirumalai	bool "ScaleMP vSMP"
5796276a074SBorislav Petkov	select HYPERVISOR_GUEST
5806a48565eSIngo Molnar	select PARAVIRT
5816a48565eSIngo Molnar	depends on X86_64 && PCI
582c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
583ead91d4bSShai Fultheim	depends on SMP
584a7f7f624SMasahiro Yamada	help
5856a48565eSIngo Molnar	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
5866a48565eSIngo Molnar	  supposed to run on these EM64T-based machines.  Only choose this option
5876a48565eSIngo Molnar	  if you have one of these machines.
5886a48565eSIngo Molnar
589c5c606d9SRavikiran G Thirumalaiconfig X86_UV
590c5c606d9SRavikiran G Thirumalai	bool "SGI Ultraviolet"
591c5c606d9SRavikiran G Thirumalai	depends on X86_64
592c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
59354c28d29SJack Steiner	depends on NUMA
5941ecb4ae5SAndrew Morton	depends on EFI
595c2209ea5SIngo Molnar	depends on KEXEC_CORE
5969d6c26e7SSuresh Siddha	depends on X86_X2APIC
5971222e564SIngo Molnar	depends on PCI
598a7f7f624SMasahiro Yamada	help
599c5c606d9SRavikiran G Thirumalai	  This option is needed in order to support SGI Ultraviolet systems.
600c5c606d9SRavikiran G Thirumalai	  If you don't have one of these, you should say N here.
601c5c606d9SRavikiran G Thirumalai
602c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms
603c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions
604506f1d07SSam Ravnborg
605ddd70cf9SJun Nakajimaconfig X86_GOLDFISH
606ddd70cf9SJun Nakajima	bool "Goldfish (Virtual Platform)"
607cb7b8023SBen Hutchings	depends on X86_EXTENDED_PLATFORM
608a7f7f624SMasahiro Yamada	help
609ddd70cf9SJun Nakajima	  Enable support for the Goldfish virtual platform used primarily
610ddd70cf9SJun Nakajima	  for Android development. Unless you are building for the Android
611ddd70cf9SJun Nakajima	  Goldfish emulator say N here.
612ddd70cf9SJun Nakajima
613c751e17bSThomas Gleixnerconfig X86_INTEL_CE
614c751e17bSThomas Gleixner	bool "CE4100 TV platform"
615c751e17bSThomas Gleixner	depends on PCI
616c751e17bSThomas Gleixner	depends on PCI_GODIRECT
6176084a6e2SJiang Liu	depends on X86_IO_APIC
618c751e17bSThomas Gleixner	depends on X86_32
619c751e17bSThomas Gleixner	depends on X86_EXTENDED_PLATFORM
62037bc9f50SDirk Brandewie	select X86_REBOOTFIXUPS
621da6b737bSSebastian Andrzej Siewior	select OF
622da6b737bSSebastian Andrzej Siewior	select OF_EARLY_FLATTREE
623a7f7f624SMasahiro Yamada	help
624c751e17bSThomas Gleixner	  Select for the Intel CE media processor (CE4100) SOC.
625c751e17bSThomas Gleixner	  This option compiles in support for the CE4100 SOC for settop
626c751e17bSThomas Gleixner	  boxes and media devices.
627c751e17bSThomas Gleixner
6284cb9b00fSDavid Cohenconfig X86_INTEL_MID
62943605ef1SAlan Cox	bool "Intel MID platform support"
63043605ef1SAlan Cox	depends on X86_EXTENDED_PLATFORM
631edc6bc78SDavid Cohen	depends on X86_PLATFORM_DEVICES
6321ea7c673SAlan Cox	depends on PCI
6333fda5bb4SAndy Shevchenko	depends on X86_64 || (PCI_GOANY && X86_32)
6341ea7c673SAlan Cox	depends on X86_IO_APIC
6354cb9b00fSDavid Cohen	select I2C
6367c9c3a1eSAlan Cox	select DW_APB_TIMER
63754b34aa0SMika Westerberg	select INTEL_SCU_PCI
638a7f7f624SMasahiro Yamada	help
6394cb9b00fSDavid Cohen	  Select to build a kernel capable of supporting Intel MID (Mobile
6404cb9b00fSDavid Cohen	  Internet Device) platform systems which do not have the PCI legacy
6414cb9b00fSDavid Cohen	  interfaces. If you are building for a PC class system say N here.
6421ea7c673SAlan Cox
6434cb9b00fSDavid Cohen	  Intel MID platforms are based on an Intel processor and chipset which
6444cb9b00fSDavid Cohen	  consume less power than most of the x86 derivatives.
64543605ef1SAlan Cox
6468bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK
6478bbc2a13SBryan O'Donoghue	bool "Intel Quark platform support"
6488bbc2a13SBryan O'Donoghue	depends on X86_32
6498bbc2a13SBryan O'Donoghue	depends on X86_EXTENDED_PLATFORM
6508bbc2a13SBryan O'Donoghue	depends on X86_PLATFORM_DEVICES
6518bbc2a13SBryan O'Donoghue	depends on X86_TSC
6528bbc2a13SBryan O'Donoghue	depends on PCI
6538bbc2a13SBryan O'Donoghue	depends on PCI_GOANY
6548bbc2a13SBryan O'Donoghue	depends on X86_IO_APIC
6558bbc2a13SBryan O'Donoghue	select IOSF_MBI
6568bbc2a13SBryan O'Donoghue	select INTEL_IMR
6579ab6eb51SAndy Shevchenko	select COMMON_CLK
658a7f7f624SMasahiro Yamada	help
6598bbc2a13SBryan O'Donoghue	  Select to include support for Quark X1000 SoC.
6608bbc2a13SBryan O'Donoghue	  Say Y here if you have a Quark based system such as the Arduino
6618bbc2a13SBryan O'Donoghue	  compatible Intel Galileo.
6628bbc2a13SBryan O'Donoghue
6633d48aab1SMika Westerbergconfig X86_INTEL_LPSS
6643d48aab1SMika Westerberg	bool "Intel Low Power Subsystem Support"
6655962dd22SSinan Kaya	depends on X86 && ACPI && PCI
6663d48aab1SMika Westerberg	select COMMON_CLK
6670f531431SMathias Nyman	select PINCTRL
668eebb3e8dSAndy Shevchenko	select IOSF_MBI
669a7f7f624SMasahiro Yamada	help
6703d48aab1SMika Westerberg	  Select to build support for Intel Low Power Subsystem such as
6713d48aab1SMika Westerberg	  found on Intel Lynxpoint PCH. Selecting this option enables
6720f531431SMathias Nyman	  things like clock tree (common clock framework) and pincontrol
6730f531431SMathias Nyman	  which are needed by the LPSS peripheral drivers.
6743d48aab1SMika Westerberg
67592082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE
67692082a88SKen Xue	bool "AMD ACPI2Platform devices support"
67792082a88SKen Xue	depends on ACPI
67892082a88SKen Xue	select COMMON_CLK
67992082a88SKen Xue	select PINCTRL
680a7f7f624SMasahiro Yamada	help
68192082a88SKen Xue	  Select to interpret AMD specific ACPI device to platform device
68292082a88SKen Xue	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
68392082a88SKen Xue	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
68492082a88SKen Xue	  implemented under PINCTRL subsystem.
68592082a88SKen Xue
686ced3ce76SDavid E. Boxconfig IOSF_MBI
687ced3ce76SDavid E. Box	tristate "Intel SoC IOSF Sideband support for SoC platforms"
688ced3ce76SDavid E. Box	depends on PCI
689a7f7f624SMasahiro Yamada	help
690ced3ce76SDavid E. Box	  This option enables sideband register access support for Intel SoC
691ced3ce76SDavid E. Box	  platforms. On these platforms the IOSF sideband is used in lieu of
692ced3ce76SDavid E. Box	  MSR's for some register accesses, mostly but not limited to thermal
693ced3ce76SDavid E. Box	  and power. Drivers may query the availability of this device to
694ced3ce76SDavid E. Box	  determine if they need the sideband in order to work on these
695ced3ce76SDavid E. Box	  platforms. The sideband is available on the following SoC products.
696ced3ce76SDavid E. Box	  This list is not meant to be exclusive.
697ced3ce76SDavid E. Box	   - BayTrail
698ced3ce76SDavid E. Box	   - Braswell
699ced3ce76SDavid E. Box	   - Quark
700ced3ce76SDavid E. Box
701ced3ce76SDavid E. Box	  You should say Y if you are running a kernel on one of these SoC's.
702ced3ce76SDavid E. Box
703ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG
704ed2226bdSDavid E. Box	bool "Enable IOSF sideband access through debugfs"
705ed2226bdSDavid E. Box	depends on IOSF_MBI && DEBUG_FS
706a7f7f624SMasahiro Yamada	help
707ed2226bdSDavid E. Box	  Select this option to expose the IOSF sideband access registers (MCR,
708ed2226bdSDavid E. Box	  MDR, MCRX) through debugfs to write and read register information from
709ed2226bdSDavid E. Box	  different units on the SoC. This is most useful for obtaining device
710ed2226bdSDavid E. Box	  state information for debug and analysis. As this is a general access
711ed2226bdSDavid E. Box	  mechanism, users of this option would have specific knowledge of the
712ed2226bdSDavid E. Box	  device they want to access.
713ed2226bdSDavid E. Box
714ed2226bdSDavid E. Box	  If you don't require the option or are in doubt, say N.
715ed2226bdSDavid E. Box
716c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X
717c5c606d9SRavikiran G Thirumalai	bool "RDC R-321x SoC"
718506f1d07SSam Ravnborg	depends on X86_32
719c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
720c5c606d9SRavikiran G Thirumalai	select M486
721c5c606d9SRavikiran G Thirumalai	select X86_REBOOTFIXUPS
722a7f7f624SMasahiro Yamada	help
723c5c606d9SRavikiran G Thirumalai	  This option is needed for RDC R-321x system-on-chip, also known
724c5c606d9SRavikiran G Thirumalai	  as R-8610-(G).
725c5c606d9SRavikiran G Thirumalai	  If you don't have one of these chips, you should say N here.
726c5c606d9SRavikiran G Thirumalai
727e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD
7289c398017SIngo Molnar	bool "Support non-standard 32-bit SMP architectures"
7299c398017SIngo Molnar	depends on X86_32 && SMP
730c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
731a7f7f624SMasahiro Yamada	help
732b5660ba7SH. Peter Anvin	  This option compiles in the bigsmp and STA2X11 default
733b5660ba7SH. Peter Anvin	  subarchitectures.  It is intended for a generic binary
734b5660ba7SH. Peter Anvin	  kernel. If you select them all, kernel will probe it one by
735b5660ba7SH. Peter Anvin	  one and will fallback to default.
736d49c4288SYinghai Lu
737c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms
738d49c4288SYinghai Lu
739d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE
7406fc108a0SJan Beulich	def_bool y
741d949f36fSLinus Torvalds	# MCE code calls memory_failure():
742d949f36fSLinus Torvalds	depends on X86_MCE
743d949f36fSLinus Torvalds	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
744d949f36fSLinus Torvalds	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
745d949f36fSLinus Torvalds	depends on X86_64 || !SPARSEMEM
746d949f36fSLinus Torvalds	select ARCH_SUPPORTS_MEMORY_FAILURE
747d949f36fSLinus Torvalds
74883125a3aSAlessandro Rubiniconfig STA2X11
74983125a3aSAlessandro Rubini	bool "STA2X11 Companion Chip Support"
75083125a3aSAlessandro Rubini	depends on X86_32_NON_STANDARD && PCI
75183125a3aSAlessandro Rubini	select SWIOTLB
75283125a3aSAlessandro Rubini	select MFD_STA2X11
7530145071bSLinus Walleij	select GPIOLIB
754a7f7f624SMasahiro Yamada	help
75583125a3aSAlessandro Rubini	  This adds support for boards based on the STA2X11 IO-Hub,
75683125a3aSAlessandro Rubini	  a.k.a. "ConneXt". The chip is used in place of the standard
75783125a3aSAlessandro Rubini	  PC chipset, so all "standard" peripherals are missing. If this
75883125a3aSAlessandro Rubini	  option is selected the kernel will still be able to boot on
75983125a3aSAlessandro Rubini	  standard PC machines.
76083125a3aSAlessandro Rubini
76182148d1dSShérabconfig X86_32_IRIS
76282148d1dSShérab	tristate "Eurobraille/Iris poweroff module"
76382148d1dSShérab	depends on X86_32
764a7f7f624SMasahiro Yamada	help
76582148d1dSShérab	  The Iris machines from EuroBraille do not have APM or ACPI support
76682148d1dSShérab	  to shut themselves down properly.  A special I/O sequence is
76782148d1dSShérab	  needed to do so, which is what this module does at
76882148d1dSShérab	  kernel shutdown.
76982148d1dSShérab
77082148d1dSShérab	  This is only for Iris machines from EuroBraille.
77182148d1dSShérab
77282148d1dSShérab	  If unused, say N.
77382148d1dSShérab
774ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER
7753c2362e6SHarvey Harrison	def_bool y
7763c2362e6SHarvey Harrison	prompt "Single-depth WCHAN output"
777a87d0914SKen Chen	depends on X86
778a7f7f624SMasahiro Yamada	help
779506f1d07SSam Ravnborg	  Calculate simpler /proc/<PID>/wchan values. If this option
780506f1d07SSam Ravnborg	  is disabled then wchan values will recurse back to the
781506f1d07SSam Ravnborg	  caller function. This provides more accurate wchan values,
782506f1d07SSam Ravnborg	  at the expense of slightly more scheduling overhead.
783506f1d07SSam Ravnborg
784506f1d07SSam Ravnborg	  If in doubt, say "Y".
785506f1d07SSam Ravnborg
7866276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST
7876276a074SBorislav Petkov	bool "Linux guest support"
788a7f7f624SMasahiro Yamada	help
7896276a074SBorislav Petkov	  Say Y here to enable options for running Linux under various hyper-
7906276a074SBorislav Petkov	  visors. This option enables basic hypervisor detection and platform
7916276a074SBorislav Petkov	  setup.
792506f1d07SSam Ravnborg
7936276a074SBorislav Petkov	  If you say N, all options in this submenu will be skipped and
7946276a074SBorislav Petkov	  disabled, and Linux guest support won't be built in.
795506f1d07SSam Ravnborg
7966276a074SBorislav Petkovif HYPERVISOR_GUEST
797506f1d07SSam Ravnborg
798e61bd94aSEduardo Pereira Habkostconfig PARAVIRT
799e61bd94aSEduardo Pereira Habkost	bool "Enable paravirtualization code"
800a0e2bf7cSJuergen Gross	depends on HAVE_STATIC_CALL
801a7f7f624SMasahiro Yamada	help
802e61bd94aSEduardo Pereira Habkost	  This changes the kernel so it can modify itself when it is run
803e61bd94aSEduardo Pereira Habkost	  under a hypervisor, potentially improving performance significantly
804e61bd94aSEduardo Pereira Habkost	  over full virtualization.  However, when run without a hypervisor
805e61bd94aSEduardo Pereira Habkost	  the kernel is theoretically slower and slightly larger.
806e61bd94aSEduardo Pereira Habkost
807c00a280aSJuergen Grossconfig PARAVIRT_XXL
808c00a280aSJuergen Gross	bool
809c00a280aSJuergen Gross
8106276a074SBorislav Petkovconfig PARAVIRT_DEBUG
8116276a074SBorislav Petkov	bool "paravirt-ops debugging"
8126276a074SBorislav Petkov	depends on PARAVIRT && DEBUG_KERNEL
813a7f7f624SMasahiro Yamada	help
8146276a074SBorislav Petkov	  Enable to debug paravirt_ops internals.  Specifically, BUG if
8156276a074SBorislav Petkov	  a paravirt_op is missing when it is called.
8166276a074SBorislav Petkov
817b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS
818b4ecc126SJeremy Fitzhardinge	bool "Paravirtualization layer for spinlocks"
8196ea30386SKees Cook	depends on PARAVIRT && SMP
820a7f7f624SMasahiro Yamada	help
821b4ecc126SJeremy Fitzhardinge	  Paravirtualized spinlocks allow a pvops backend to replace the
822b4ecc126SJeremy Fitzhardinge	  spinlock implementation with something virtualization-friendly
823b4ecc126SJeremy Fitzhardinge	  (for example, block the virtual CPU rather than spinning).
824b4ecc126SJeremy Fitzhardinge
8254c4e4f61SRaghavendra K T	  It has a minimal impact on native kernels and gives a nice performance
8264c4e4f61SRaghavendra K T	  benefit on paravirtualized KVM / Xen kernels.
827b4ecc126SJeremy Fitzhardinge
8284c4e4f61SRaghavendra K T	  If you are unsure how to answer this question, answer Y.
829b4ecc126SJeremy Fitzhardinge
830ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR
831ecca2502SZhao Yakui	def_bool n
832ecca2502SZhao Yakui
8336276a074SBorislav Petkovsource "arch/x86/xen/Kconfig"
8346276a074SBorislav Petkov
8356276a074SBorislav Petkovconfig KVM_GUEST
8366276a074SBorislav Petkov	bool "KVM Guest support (including kvmclock)"
8376276a074SBorislav Petkov	depends on PARAVIRT
8386276a074SBorislav Petkov	select PARAVIRT_CLOCK
839a1c4423bSMarcelo Tosatti	select ARCH_CPUIDLE_HALTPOLL
840b1d40575SVitaly Kuznetsov	select X86_HV_CALLBACK_VECTOR
8416276a074SBorislav Petkov	default y
842a7f7f624SMasahiro Yamada	help
8436276a074SBorislav Petkov	  This option enables various optimizations for running under the KVM
8446276a074SBorislav Petkov	  hypervisor. It includes a paravirtualized clock, so that instead
8456276a074SBorislav Petkov	  of relying on a PIT (or probably other) emulation by the
8466276a074SBorislav Petkov	  underlying device model, the host provides the guest with
8476276a074SBorislav Petkov	  timing infrastructure such as time of day, and system time
8486276a074SBorislav Petkov
849a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL
850a1c4423bSMarcelo Tosatti	def_bool n
851a1c4423bSMarcelo Tosatti	prompt "Disable host haltpoll when loading haltpoll driver"
852a1c4423bSMarcelo Tosatti	help
853a1c4423bSMarcelo Tosatti	  If virtualized under KVM, disable host haltpoll.
854a1c4423bSMarcelo Tosatti
8557733607fSMaran Wilsonconfig PVH
8567733607fSMaran Wilson	bool "Support for running PVH guests"
857a7f7f624SMasahiro Yamada	help
8587733607fSMaran Wilson	  This option enables the PVH entry point for guest virtual machines
8597733607fSMaran Wilson	  as specified in the x86/HVM direct boot ABI.
8607733607fSMaran Wilson
8616276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING
8626276a074SBorislav Petkov	bool "Paravirtual steal time accounting"
8636276a074SBorislav Petkov	depends on PARAVIRT
864a7f7f624SMasahiro Yamada	help
8656276a074SBorislav Petkov	  Select this option to enable fine granularity task steal time
8666276a074SBorislav Petkov	  accounting. Time spent executing other tasks in parallel with
8676276a074SBorislav Petkov	  the current vCPU is discounted from the vCPU power. To account for
8686276a074SBorislav Petkov	  that, there can be a small performance impact.
8696276a074SBorislav Petkov
8706276a074SBorislav Petkov	  If in doubt, say N here.
8716276a074SBorislav Petkov
8727af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK
8737af192c9SGerd Hoffmann	bool
8747af192c9SGerd Hoffmann
8754a362601SJan Kiszkaconfig JAILHOUSE_GUEST
8764a362601SJan Kiszka	bool "Jailhouse non-root cell support"
877abde587bSArnd Bergmann	depends on X86_64 && PCI
87887e65d05SJan Kiszka	select X86_PM_TIMER
879a7f7f624SMasahiro Yamada	help
8804a362601SJan Kiszka	  This option allows to run Linux as guest in a Jailhouse non-root
8814a362601SJan Kiszka	  cell. You can leave this option disabled if you only want to start
8824a362601SJan Kiszka	  Jailhouse and run Linux afterwards in the root cell.
8834a362601SJan Kiszka
884ec7972c9SZhao Yakuiconfig ACRN_GUEST
885ec7972c9SZhao Yakui	bool "ACRN Guest support"
886ec7972c9SZhao Yakui	depends on X86_64
887498ad393SZhao Yakui	select X86_HV_CALLBACK_VECTOR
888ec7972c9SZhao Yakui	help
889ec7972c9SZhao Yakui	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
890ec7972c9SZhao Yakui	  a flexible, lightweight reference open-source hypervisor, built with
891ec7972c9SZhao Yakui	  real-time and safety-criticality in mind. It is built for embedded
892ec7972c9SZhao Yakui	  IOT with small footprint and real-time features. More details can be
893ec7972c9SZhao Yakui	  found in https://projectacrn.org/.
894ec7972c9SZhao Yakui
89559bd54a8SKuppuswamy Sathyanarayananconfig INTEL_TDX_GUEST
89659bd54a8SKuppuswamy Sathyanarayanan	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
89759bd54a8SKuppuswamy Sathyanarayanan	depends on X86_64 && CPU_SUP_INTEL
89859bd54a8SKuppuswamy Sathyanarayanan	depends on X86_X2APIC
89975d090fdSKirill A. Shutemov	depends on EFI_STUB
90041394e33SKirill A. Shutemov	select ARCH_HAS_CC_PLATFORM
901968b4931SKirill A. Shutemov	select X86_MEM_ENCRYPT
90277a512e3SSean Christopherson	select X86_MCE
90375d090fdSKirill A. Shutemov	select UNACCEPTED_MEMORY
90459bd54a8SKuppuswamy Sathyanarayanan	help
90559bd54a8SKuppuswamy Sathyanarayanan	  Support running as a guest under Intel TDX.  Without this support,
90659bd54a8SKuppuswamy Sathyanarayanan	  the guest kernel can not boot or run under TDX.
90759bd54a8SKuppuswamy Sathyanarayanan	  TDX includes memory encryption and integrity capabilities
90859bd54a8SKuppuswamy Sathyanarayanan	  which protect the confidentiality and integrity of guest
90959bd54a8SKuppuswamy Sathyanarayanan	  memory contents and CPU state. TDX guests are protected from
91059bd54a8SKuppuswamy Sathyanarayanan	  some attacks from the VMM.
91159bd54a8SKuppuswamy Sathyanarayanan
9126276a074SBorislav Petkovendif # HYPERVISOR_GUEST
91397349135SJeremy Fitzhardinge
914506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu"
915506f1d07SSam Ravnborg
916506f1d07SSam Ravnborgconfig HPET_TIMER
9173c2362e6SHarvey Harrison	def_bool X86_64
918506f1d07SSam Ravnborg	prompt "HPET Timer Support" if X86_32
919a7f7f624SMasahiro Yamada	help
920506f1d07SSam Ravnborg	  Use the IA-PC HPET (High Precision Event Timer) to manage
921506f1d07SSam Ravnborg	  time in preference to the PIT and RTC, if a HPET is
922506f1d07SSam Ravnborg	  present.
923506f1d07SSam Ravnborg	  HPET is the next generation timer replacing legacy 8254s.
924506f1d07SSam Ravnborg	  The HPET provides a stable time base on SMP
925506f1d07SSam Ravnborg	  systems, unlike the TSC, but it is more expensive to access,
9264e7f9df2SMichael S. Tsirkin	  as it is off-chip.  The interface used is documented
9274e7f9df2SMichael S. Tsirkin	  in the HPET spec, revision 1.
928506f1d07SSam Ravnborg
929506f1d07SSam Ravnborg	  You can safely choose Y here.  However, HPET will only be
930506f1d07SSam Ravnborg	  activated if the platform and the BIOS support this feature.
931506f1d07SSam Ravnborg	  Otherwise the 8254 will be used for timing services.
932506f1d07SSam Ravnborg
933506f1d07SSam Ravnborg	  Choose N to continue using the legacy 8254 timer.
934506f1d07SSam Ravnborg
935506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC
9363c2362e6SHarvey Harrison	def_bool y
9373228e1dcSAnand K Mistry	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
938506f1d07SSam Ravnborg
9396a108a14SDavid Rientjes# Mark as expert because too many people got it wrong.
940506f1d07SSam Ravnborg# The code disables itself when not needed.
9417ae9392cSThomas Petazzoniconfig DMI
9427ae9392cSThomas Petazzoni	default y
943cf074402SArd Biesheuvel	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
9446a108a14SDavid Rientjes	bool "Enable DMI scanning" if EXPERT
945a7f7f624SMasahiro Yamada	help
9467ae9392cSThomas Petazzoni	  Enabled scanning of DMI to identify machine quirks. Say Y
9477ae9392cSThomas Petazzoni	  here unless you have verified that your setup is not
9487ae9392cSThomas Petazzoni	  affected by entries in the DMI blacklist. Required by PNP
9497ae9392cSThomas Petazzoni	  BIOS code.
9507ae9392cSThomas Petazzoni
951506f1d07SSam Ravnborgconfig GART_IOMMU
95238901f1cSAndi Kleen	bool "Old AMD GART IOMMU support"
9532f9237d4SChristoph Hellwig	select DMA_OPS
954a4ce5a48SChristoph Hellwig	select IOMMU_HELPER
955506f1d07SSam Ravnborg	select SWIOTLB
95623ac4ae8SAndreas Herrmann	depends on X86_64 && PCI && AMD_NB
957a7f7f624SMasahiro Yamada	help
958ced3c42cSIngo Molnar	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
959ced3c42cSIngo Molnar	  GART based hardware IOMMUs.
960ced3c42cSIngo Molnar
961ced3c42cSIngo Molnar	  The GART supports full DMA access for devices with 32-bit access
962ced3c42cSIngo Molnar	  limitations, on systems with more than 3 GB. This is usually needed
963ced3c42cSIngo Molnar	  for USB, sound, many IDE/SATA chipsets and some other devices.
964ced3c42cSIngo Molnar
965ced3c42cSIngo Molnar	  Newer systems typically have a modern AMD IOMMU, supported via
966ced3c42cSIngo Molnar	  the CONFIG_AMD_IOMMU=y config option.
967ced3c42cSIngo Molnar
968ced3c42cSIngo Molnar	  In normal configurations this driver is only active when needed:
969ced3c42cSIngo Molnar	  there's more than 3 GB of memory and the system contains a
970ced3c42cSIngo Molnar	  32-bit limited device.
971ced3c42cSIngo Molnar
972ced3c42cSIngo Molnar	  If unsure, say Y.
973506f1d07SSam Ravnborg
9748b766b0fSMichal Suchanekconfig BOOT_VESA_SUPPORT
9758b766b0fSMichal Suchanek	bool
9768b766b0fSMichal Suchanek	help
9778b766b0fSMichal Suchanek	  If true, at least one selected framebuffer driver can take advantage
9788b766b0fSMichal Suchanek	  of VESA video modes set at an early boot stage via the vga= parameter.
9798b766b0fSMichal Suchanek
9801184dc2fSMike Travisconfig MAXSMP
981ddb0c5a6SSamuel Thibault	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
9826ea30386SKees Cook	depends on X86_64 && SMP && DEBUG_KERNEL
98336f5101aSMike Travis	select CPUMASK_OFFSTACK
984a7f7f624SMasahiro Yamada	help
985ddb0c5a6SSamuel Thibault	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
9861184dc2fSMike Travis	  If unsure, say N.
987506f1d07SSam Ravnborg
988aec6487eSIngo Molnar#
989aec6487eSIngo Molnar# The maximum number of CPUs supported:
990aec6487eSIngo Molnar#
991aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
992aec6487eSIngo Molnar# and which can be configured interactively in the
993aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
994aec6487eSIngo Molnar#
995aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on
996aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel.
997aec6487eSIngo Molnar#
998aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable
999aec6487eSIngo Molnar#   interactive configuration. )
1000aec6487eSIngo Molnar#
1001a0d0bb4dSRandy Dunlap
1002aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN
1003a0d0bb4dSRandy Dunlap	int
1004aec6487eSIngo Molnar	default NR_CPUS_RANGE_END if MAXSMP
1005a0d0bb4dSRandy Dunlap	default    1 if !SMP
1006a0d0bb4dSRandy Dunlap	default    2
1007a0d0bb4dSRandy Dunlap
1008aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END
1009a0d0bb4dSRandy Dunlap	int
1010a0d0bb4dSRandy Dunlap	depends on X86_32
1011aec6487eSIngo Molnar	default   64 if  SMP &&  X86_BIGSMP
1012aec6487eSIngo Molnar	default    8 if  SMP && !X86_BIGSMP
1013a0d0bb4dSRandy Dunlap	default    1 if !SMP
1014a0d0bb4dSRandy Dunlap
1015aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END
1016a0d0bb4dSRandy Dunlap	int
1017a0d0bb4dSRandy Dunlap	depends on X86_64
10181edae1aeSScott Wood	default 8192 if  SMP && CPUMASK_OFFSTACK
10191edae1aeSScott Wood	default  512 if  SMP && !CPUMASK_OFFSTACK
1020a0d0bb4dSRandy Dunlap	default    1 if !SMP
1021aec6487eSIngo Molnar
1022aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT
1023aec6487eSIngo Molnar	int
1024aec6487eSIngo Molnar	depends on X86_32
1025aec6487eSIngo Molnar	default   32 if  X86_BIGSMP
1026aec6487eSIngo Molnar	default    8 if  SMP
1027aec6487eSIngo Molnar	default    1 if !SMP
1028aec6487eSIngo Molnar
1029aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT
1030aec6487eSIngo Molnar	int
1031aec6487eSIngo Molnar	depends on X86_64
1032a0d0bb4dSRandy Dunlap	default 8192 if  MAXSMP
1033a0d0bb4dSRandy Dunlap	default   64 if  SMP
1034aec6487eSIngo Molnar	default    1 if !SMP
1035a0d0bb4dSRandy Dunlap
1036506f1d07SSam Ravnborgconfig NR_CPUS
103736f5101aSMike Travis	int "Maximum number of CPUs" if SMP && !MAXSMP
1038aec6487eSIngo Molnar	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1039aec6487eSIngo Molnar	default NR_CPUS_DEFAULT
1040a7f7f624SMasahiro Yamada	help
1041506f1d07SSam Ravnborg	  This allows you to specify the maximum number of CPUs which this
1042bb61ccc7SJosh Boyer	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1043cad14bb9SKirill A. Shutemov	  supported value is 8192, otherwise the maximum value is 512.  The
1044506f1d07SSam Ravnborg	  minimum value which makes sense is 2.
1045506f1d07SSam Ravnborg
1046aec6487eSIngo Molnar	  This is purely to save memory: each supported CPU adds about 8KB
1047aec6487eSIngo Molnar	  to the kernel image.
1048506f1d07SSam Ravnborg
104966558b73STim Chenconfig SCHED_CLUSTER
105066558b73STim Chen	bool "Cluster scheduler support"
105166558b73STim Chen	depends on SMP
105266558b73STim Chen	default y
105366558b73STim Chen	help
105466558b73STim Chen	  Cluster scheduler support improves the CPU scheduler's decision
105566558b73STim Chen	  making when dealing with machines that have clusters of CPUs.
105666558b73STim Chen	  Cluster usually means a couple of CPUs which are placed closely
105766558b73STim Chen	  by sharing mid-level caches, last-level cache tags or internal
105866558b73STim Chen	  busses.
105966558b73STim Chen
1060506f1d07SSam Ravnborgconfig SCHED_SMT
1061dbe73364SThomas Gleixner	def_bool y if SMP
1062506f1d07SSam Ravnborg
1063506f1d07SSam Ravnborgconfig SCHED_MC
10643c2362e6SHarvey Harrison	def_bool y
10653c2362e6SHarvey Harrison	prompt "Multi-core scheduler support"
1066c8e56d20SBorislav Petkov	depends on SMP
1067a7f7f624SMasahiro Yamada	help
1068506f1d07SSam Ravnborg	  Multi-core scheduler support improves the CPU scheduler's decision
1069506f1d07SSam Ravnborg	  making when dealing with multi-core CPU chips at a cost of slightly
1070506f1d07SSam Ravnborg	  increased overhead in some places. If unsure say N here.
1071506f1d07SSam Ravnborg
1072de966cf4STim Chenconfig SCHED_MC_PRIO
1073de966cf4STim Chen	bool "CPU core priorities scheduler support"
10743598e577SMeng Li	depends on SCHED_MC
10753598e577SMeng Li	select X86_INTEL_PSTATE if CPU_SUP_INTEL
10763598e577SMeng Li	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
10770a21fc12SIngo Molnar	select CPU_FREQ
1078de966cf4STim Chen	default y
1079a7f7f624SMasahiro Yamada	help
1080de966cf4STim Chen	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1081de966cf4STim Chen	  core ordering determined at manufacturing time, which allows
1082de966cf4STim Chen	  certain cores to reach higher turbo frequencies (when running
1083de966cf4STim Chen	  single threaded workloads) than others.
1084de966cf4STim Chen
1085de966cf4STim Chen	  Enabling this kernel feature teaches the scheduler about
1086de966cf4STim Chen	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1087de966cf4STim Chen	  scheduler's CPU selection logic accordingly, so that higher
1088de966cf4STim Chen	  overall system performance can be achieved.
1089de966cf4STim Chen
1090de966cf4STim Chen	  This feature will have no effect on CPUs without this feature.
1091de966cf4STim Chen
1092de966cf4STim Chen	  If unsure say Y here.
10935e76b2abSTim Chen
109430b8b006SThomas Gleixnerconfig UP_LATE_INIT
109530b8b006SThomas Gleixner	def_bool y
1096ba360f88SThomas Gleixner	depends on !SMP && X86_LOCAL_APIC
109730b8b006SThomas Gleixner
1098506f1d07SSam Ravnborgconfig X86_UP_APIC
109950849eefSJan Beulich	bool "Local APIC support on uniprocessors" if !PCI_MSI
110050849eefSJan Beulich	default PCI_MSI
110138a1dfdaSBryan O'Donoghue	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1102a7f7f624SMasahiro Yamada	help
1103506f1d07SSam Ravnborg	  A local APIC (Advanced Programmable Interrupt Controller) is an
1104506f1d07SSam Ravnborg	  integrated interrupt controller in the CPU. If you have a single-CPU
1105506f1d07SSam Ravnborg	  system which has a processor with a local APIC, you can say Y here to
1106506f1d07SSam Ravnborg	  enable and use it. If you say Y here even though your machine doesn't
1107506f1d07SSam Ravnborg	  have a local APIC, then the kernel will still run with no slowdown at
1108506f1d07SSam Ravnborg	  all. The local APIC supports CPU-generated self-interrupts (timer,
1109506f1d07SSam Ravnborg	  performance counters), and the NMI watchdog which detects hard
1110506f1d07SSam Ravnborg	  lockups.
1111506f1d07SSam Ravnborg
1112506f1d07SSam Ravnborgconfig X86_UP_IOAPIC
1113506f1d07SSam Ravnborg	bool "IO-APIC support on uniprocessors"
1114506f1d07SSam Ravnborg	depends on X86_UP_APIC
1115a7f7f624SMasahiro Yamada	help
1116506f1d07SSam Ravnborg	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1117506f1d07SSam Ravnborg	  SMP-capable replacement for PC-style interrupt controllers. Most
1118506f1d07SSam Ravnborg	  SMP systems and many recent uniprocessor systems have one.
1119506f1d07SSam Ravnborg
1120506f1d07SSam Ravnborg	  If you have a single-CPU system with an IO-APIC, you can say Y here
1121506f1d07SSam Ravnborg	  to use it. If you say Y here even though your machine doesn't have
1122506f1d07SSam Ravnborg	  an IO-APIC, then the kernel will still run with no slowdown at all.
1123506f1d07SSam Ravnborg
1124506f1d07SSam Ravnborgconfig X86_LOCAL_APIC
11253c2362e6SHarvey Harrison	def_bool y
11260dbc6078SThomas Petazzoni	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1127b5dc8e6cSJiang Liu	select IRQ_DOMAIN_HIERARCHY
1128506f1d07SSam Ravnborg
1129506f1d07SSam Ravnborgconfig X86_IO_APIC
1130b1da1e71SJan Beulich	def_bool y
1131b1da1e71SJan Beulich	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1132506f1d07SSam Ravnborg
113341b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS
113441b9eb26SStefan Assmann	bool "Reroute for broken boot IRQs"
113541b9eb26SStefan Assmann	depends on X86_IO_APIC
1136a7f7f624SMasahiro Yamada	help
113741b9eb26SStefan Assmann	  This option enables a workaround that fixes a source of
113841b9eb26SStefan Assmann	  spurious interrupts. This is recommended when threaded
113941b9eb26SStefan Assmann	  interrupt handling is used on systems where the generation of
114041b9eb26SStefan Assmann	  superfluous "boot interrupts" cannot be disabled.
114141b9eb26SStefan Assmann
114241b9eb26SStefan Assmann	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
114341b9eb26SStefan Assmann	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
114441b9eb26SStefan Assmann	  kernel does during interrupt handling). On chipsets where this
114541b9eb26SStefan Assmann	  boot IRQ generation cannot be disabled, this workaround keeps
114641b9eb26SStefan Assmann	  the original IRQ line masked so that only the equivalent "boot
114741b9eb26SStefan Assmann	  IRQ" is delivered to the CPUs. The workaround also tells the
114841b9eb26SStefan Assmann	  kernel to set up the IRQ handler on the boot IRQ line. In this
114941b9eb26SStefan Assmann	  way only one interrupt is delivered to the kernel. Otherwise
115041b9eb26SStefan Assmann	  the spurious second interrupt may cause the kernel to bring
115141b9eb26SStefan Assmann	  down (vital) interrupt lines.
115241b9eb26SStefan Assmann
115341b9eb26SStefan Assmann	  Only affects "broken" chipsets. Interrupt sharing may be
115441b9eb26SStefan Assmann	  increased on these systems.
115541b9eb26SStefan Assmann
1156506f1d07SSam Ravnborgconfig X86_MCE
1157bab9bc65SAndi Kleen	bool "Machine Check / overheating reporting"
1158648ed940SChen, Gong	select GENERIC_ALLOCATOR
1159e57dbaf7SBorislav Petkov	default y
1160a7f7f624SMasahiro Yamada	help
1161bab9bc65SAndi Kleen	  Machine Check support allows the processor to notify the
1162bab9bc65SAndi Kleen	  kernel if it detects a problem (e.g. overheating, data corruption).
1163506f1d07SSam Ravnborg	  The action the kernel takes depends on the severity of the problem,
1164bab9bc65SAndi Kleen	  ranging from warning messages to halting the machine.
11654efc0670SAndi Kleen
11665de97c9fSTony Luckconfig X86_MCELOG_LEGACY
11675de97c9fSTony Luck	bool "Support for deprecated /dev/mcelog character device"
11685de97c9fSTony Luck	depends on X86_MCE
1169a7f7f624SMasahiro Yamada	help
11705de97c9fSTony Luck	  Enable support for /dev/mcelog which is needed by the old mcelog
11715de97c9fSTony Luck	  userspace logging daemon. Consider switching to the new generation
11725de97c9fSTony Luck	  rasdaemon solution.
11735de97c9fSTony Luck
1174506f1d07SSam Ravnborgconfig X86_MCE_INTEL
11753c2362e6SHarvey Harrison	def_bool y
11763c2362e6SHarvey Harrison	prompt "Intel MCE features"
1177c1ebf835SAndi Kleen	depends on X86_MCE && X86_LOCAL_APIC
1178a7f7f624SMasahiro Yamada	help
1179506f1d07SSam Ravnborg	  Additional support for intel specific MCE features such as
1180506f1d07SSam Ravnborg	  the thermal monitor.
1181506f1d07SSam Ravnborg
1182506f1d07SSam Ravnborgconfig X86_MCE_AMD
11833c2362e6SHarvey Harrison	def_bool y
11843c2362e6SHarvey Harrison	prompt "AMD MCE features"
1185f5382de9SYazen Ghannam	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1186a7f7f624SMasahiro Yamada	help
1187506f1d07SSam Ravnborg	  Additional support for AMD specific MCE features such as
1188506f1d07SSam Ravnborg	  the DRAM Error Threshold.
1189506f1d07SSam Ravnborg
11904efc0670SAndi Kleenconfig X86_ANCIENT_MCE
11916fc108a0SJan Beulich	bool "Support for old Pentium 5 / WinChip machine checks"
1192c31d9633SAndi Kleen	depends on X86_32 && X86_MCE
1193a7f7f624SMasahiro Yamada	help
11944efc0670SAndi Kleen	  Include support for machine check handling on old Pentium 5 or WinChip
11955065a706SMasanari Iida	  systems. These typically need to be enabled explicitly on the command
11964efc0670SAndi Kleen	  line.
11974efc0670SAndi Kleen
1198b2762686SAndi Kleenconfig X86_MCE_THRESHOLD
1199b2762686SAndi Kleen	depends on X86_MCE_AMD || X86_MCE_INTEL
12006fc108a0SJan Beulich	def_bool y
1201b2762686SAndi Kleen
1202ea149b36SAndi Kleenconfig X86_MCE_INJECT
1203bc8e80d5SBorislav Petkov	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1204ea149b36SAndi Kleen	tristate "Machine check injector support"
1205a7f7f624SMasahiro Yamada	help
1206ea149b36SAndi Kleen	  Provide support for injecting machine checks for testing purposes.
1207ea149b36SAndi Kleen	  If you don't know what a machine check is and you don't do kernel
1208ea149b36SAndi Kleen	  QA it is safe to say n.
1209ea149b36SAndi Kleen
121007dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig"
1211e633c65aSKan Liang
12125aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86
12131e642812SIngo Molnar	bool "Legacy VM86 support"
1214506f1d07SSam Ravnborg	depends on X86_32
1215a7f7f624SMasahiro Yamada	help
12165aef51c3SAndy Lutomirski	  This option allows user programs to put the CPU into V8086
12175aef51c3SAndy Lutomirski	  mode, which is an 80286-era approximation of 16-bit real mode.
12185aef51c3SAndy Lutomirski
12195aef51c3SAndy Lutomirski	  Some very old versions of X and/or vbetool require this option
12205aef51c3SAndy Lutomirski	  for user mode setting.  Similarly, DOSEMU will use it if
12215aef51c3SAndy Lutomirski	  available to accelerate real mode DOS programs.  However, any
12225aef51c3SAndy Lutomirski	  recent version of DOSEMU, X, or vbetool should be fully
12235aef51c3SAndy Lutomirski	  functional even without kernel VM86 support, as they will all
12241e642812SIngo Molnar	  fall back to software emulation. Nevertheless, if you are using
12251e642812SIngo Molnar	  a 16-bit DOS program where 16-bit performance matters, vm86
12261e642812SIngo Molnar	  mode might be faster than emulation and you might want to
12271e642812SIngo Molnar	  enable this option.
12285aef51c3SAndy Lutomirski
12291e642812SIngo Molnar	  Note that any app that works on a 64-bit kernel is unlikely to
12301e642812SIngo Molnar	  need this option, as 64-bit kernels don't, and can't, support
12311e642812SIngo Molnar	  V8086 mode. This option is also unrelated to 16-bit protected
12321e642812SIngo Molnar	  mode and is not needed to run most 16-bit programs under Wine.
12335aef51c3SAndy Lutomirski
12341e642812SIngo Molnar	  Enabling this option increases the complexity of the kernel
12351e642812SIngo Molnar	  and slows down exception handling a tiny bit.
12365aef51c3SAndy Lutomirski
12371e642812SIngo Molnar	  If unsure, say N here.
12385aef51c3SAndy Lutomirski
12395aef51c3SAndy Lutomirskiconfig VM86
12405aef51c3SAndy Lutomirski	bool
12415aef51c3SAndy Lutomirski	default X86_LEGACY_VM86
124234273f41SH. Peter Anvin
124334273f41SH. Peter Anvinconfig X86_16BIT
124434273f41SH. Peter Anvin	bool "Enable support for 16-bit segments" if EXPERT
124534273f41SH. Peter Anvin	default y
1246a5b9e5a2SAndy Lutomirski	depends on MODIFY_LDT_SYSCALL
1247a7f7f624SMasahiro Yamada	help
124834273f41SH. Peter Anvin	  This option is required by programs like Wine to run 16-bit
124934273f41SH. Peter Anvin	  protected mode legacy code on x86 processors.  Disabling
125034273f41SH. Peter Anvin	  this option saves about 300 bytes on i386, or around 6K text
125134273f41SH. Peter Anvin	  plus 16K runtime memory on x86-64,
125234273f41SH. Peter Anvin
125334273f41SH. Peter Anvinconfig X86_ESPFIX32
125434273f41SH. Peter Anvin	def_bool y
125534273f41SH. Peter Anvin	depends on X86_16BIT && X86_32
1256506f1d07SSam Ravnborg
1257197725deSH. Peter Anvinconfig X86_ESPFIX64
1258197725deSH. Peter Anvin	def_bool y
125934273f41SH. Peter Anvin	depends on X86_16BIT && X86_64
1260506f1d07SSam Ravnborg
12611ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION
12621ad83c85SAndy Lutomirski	bool "Enable vsyscall emulation" if EXPERT
12631ad83c85SAndy Lutomirski	default y
12641ad83c85SAndy Lutomirski	depends on X86_64
1265a7f7f624SMasahiro Yamada	help
12661ad83c85SAndy Lutomirski	  This enables emulation of the legacy vsyscall page.  Disabling
12671ad83c85SAndy Lutomirski	  it is roughly equivalent to booting with vsyscall=none, except
12681ad83c85SAndy Lutomirski	  that it will also disable the helpful warning if a program
12691ad83c85SAndy Lutomirski	  tries to use a vsyscall.  With this option set to N, offending
12701ad83c85SAndy Lutomirski	  programs will just segfault, citing addresses of the form
12711ad83c85SAndy Lutomirski	  0xffffffffff600?00.
12721ad83c85SAndy Lutomirski
12731ad83c85SAndy Lutomirski	  This option is required by many programs built before 2013, and
12741ad83c85SAndy Lutomirski	  care should be used even with newer programs if set to N.
12751ad83c85SAndy Lutomirski
12761ad83c85SAndy Lutomirski	  Disabling this option saves about 7K of kernel size and
12771ad83c85SAndy Lutomirski	  possibly 4K of additional runtime pagetable memory.
12781ad83c85SAndy Lutomirski
1279111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM
1280111e7b15SThomas Gleixner	bool "IOPERM and IOPL Emulation"
1281a24ca997SThomas Gleixner	default y
1282a7f7f624SMasahiro Yamada	help
1283111e7b15SThomas Gleixner	  This enables the ioperm() and iopl() syscalls which are necessary
1284111e7b15SThomas Gleixner	  for legacy applications.
1285111e7b15SThomas Gleixner
1286c8137aceSThomas Gleixner	  Legacy IOPL support is an overbroad mechanism which allows user
1287c8137aceSThomas Gleixner	  space aside of accessing all 65536 I/O ports also to disable
1288c8137aceSThomas Gleixner	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1289c8137aceSThomas Gleixner	  capabilities and permission from potentially active security
1290c8137aceSThomas Gleixner	  modules.
1291c8137aceSThomas Gleixner
1292c8137aceSThomas Gleixner	  The emulation restricts the functionality of the syscall to
1293c8137aceSThomas Gleixner	  only allowing the full range I/O port access, but prevents the
1294a24ca997SThomas Gleixner	  ability to disable interrupts from user space which would be
1295a24ca997SThomas Gleixner	  granted if the hardware IOPL mechanism would be used.
1296c8137aceSThomas Gleixner
1297506f1d07SSam Ravnborgconfig TOSHIBA
1298506f1d07SSam Ravnborg	tristate "Toshiba Laptop support"
1299506f1d07SSam Ravnborg	depends on X86_32
1300a7f7f624SMasahiro Yamada	help
1301506f1d07SSam Ravnborg	  This adds a driver to safely access the System Management Mode of
1302506f1d07SSam Ravnborg	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1303506f1d07SSam Ravnborg	  not work on models with a Phoenix BIOS. The System Management Mode
1304506f1d07SSam Ravnborg	  is used to set the BIOS and power saving options on Toshiba portables.
1305506f1d07SSam Ravnborg
1306506f1d07SSam Ravnborg	  For information on utilities to make use of this driver see the
1307506f1d07SSam Ravnborg	  Toshiba Linux utilities web site at:
1308506f1d07SSam Ravnborg	  <http://www.buzzard.org.uk/toshiba/>.
1309506f1d07SSam Ravnborg
1310506f1d07SSam Ravnborg	  Say Y if you intend to run this kernel on a Toshiba portable.
1311506f1d07SSam Ravnborg	  Say N otherwise.
1312506f1d07SSam Ravnborg
1313506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS
13149ba16087SJan Beulich	bool "Enable X86 board specific fixups for reboot"
13159ba16087SJan Beulich	depends on X86_32
1316a7f7f624SMasahiro Yamada	help
1317506f1d07SSam Ravnborg	  This enables chipset and/or board specific fixups to be done
1318506f1d07SSam Ravnborg	  in order to get reboot to work correctly. This is only needed on
1319506f1d07SSam Ravnborg	  some combinations of hardware and BIOS. The symptom, for which
1320506f1d07SSam Ravnborg	  this config is intended, is when reboot ends with a stalled/hung
1321506f1d07SSam Ravnborg	  system.
1322506f1d07SSam Ravnborg
1323506f1d07SSam Ravnborg	  Currently, the only fixup is for the Geode machines using
13245e3a77e9SFlorian Fainelli	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1325506f1d07SSam Ravnborg
1326506f1d07SSam Ravnborg	  Say Y if you want to enable the fixup. Currently, it's safe to
1327506f1d07SSam Ravnborg	  enable this option even if you don't need it.
1328506f1d07SSam Ravnborg	  Say N otherwise.
1329506f1d07SSam Ravnborg
1330506f1d07SSam Ravnborgconfig MICROCODE
1331e6bcfdd7SThomas Gleixner	def_bool y
133280030e3dSBorislav Petkov	depends on CPU_SUP_AMD || CPU_SUP_INTEL
133380cc9f10SPeter Oruba
1334fdbd4381SThomas Gleixnerconfig MICROCODE_INITRD32
1335fdbd4381SThomas Gleixner	def_bool y
1336fdbd4381SThomas Gleixner	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1337fdbd4381SThomas Gleixner
1338a77a94f8SBorislav Petkovconfig MICROCODE_LATE_LOADING
1339a77a94f8SBorislav Petkov	bool "Late microcode loading (DANGEROUS)"
1340c02f48e0SBorislav Petkov	default n
1341634ac23aSThomas Gleixner	depends on MICROCODE && SMP
1342a7f7f624SMasahiro Yamada	help
1343a77a94f8SBorislav Petkov	  Loading microcode late, when the system is up and executing instructions
1344a77a94f8SBorislav Petkov	  is a tricky business and should be avoided if possible. Just the sequence
1345a77a94f8SBorislav Petkov	  of synchronizing all cores and SMT threads is one fragile dance which does
1346a77a94f8SBorislav Petkov	  not guarantee that cores might not softlock after the loading. Therefore,
13479407bda8SThomas Gleixner	  use this at your own risk. Late loading taints the kernel unless the
13489407bda8SThomas Gleixner	  microcode header indicates that it is safe for late loading via the
13499407bda8SThomas Gleixner	  minimal revision check. This minimal revision check can be enforced on
13509407bda8SThomas Gleixner	  the kernel command line with "microcode.minrev=Y".
13519407bda8SThomas Gleixner
13529407bda8SThomas Gleixnerconfig MICROCODE_LATE_FORCE_MINREV
13539407bda8SThomas Gleixner	bool "Enforce late microcode loading minimal revision check"
13549407bda8SThomas Gleixner	default n
13559407bda8SThomas Gleixner	depends on MICROCODE_LATE_LOADING
13569407bda8SThomas Gleixner	help
13579407bda8SThomas Gleixner	  To prevent that users load microcode late which modifies already
13589407bda8SThomas Gleixner	  in use features, newer microcode patches have a minimum revision field
13599407bda8SThomas Gleixner	  in the microcode header, which tells the kernel which minimum
13609407bda8SThomas Gleixner	  revision must be active in the CPU to safely load that new microcode
13619407bda8SThomas Gleixner	  late into the running system. If disabled the check will not
13629407bda8SThomas Gleixner	  be enforced but the kernel will be tainted when the minimal
13639407bda8SThomas Gleixner	  revision check fails.
13649407bda8SThomas Gleixner
13659407bda8SThomas Gleixner	  This minimal revision check can also be controlled via the
13669407bda8SThomas Gleixner	  "microcode.minrev" parameter on the kernel command line.
13679407bda8SThomas Gleixner
13689407bda8SThomas Gleixner	  If unsure say Y.
1369506f1d07SSam Ravnborg
1370506f1d07SSam Ravnborgconfig X86_MSR
1371506f1d07SSam Ravnborg	tristate "/dev/cpu/*/msr - Model-specific register support"
1372a7f7f624SMasahiro Yamada	help
1373506f1d07SSam Ravnborg	  This device gives privileged processes access to the x86
1374506f1d07SSam Ravnborg	  Model-Specific Registers (MSRs).  It is a character device with
1375506f1d07SSam Ravnborg	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1376506f1d07SSam Ravnborg	  MSR accesses are directed to a specific CPU on multi-processor
1377506f1d07SSam Ravnborg	  systems.
1378506f1d07SSam Ravnborg
1379506f1d07SSam Ravnborgconfig X86_CPUID
1380506f1d07SSam Ravnborg	tristate "/dev/cpu/*/cpuid - CPU information support"
1381a7f7f624SMasahiro Yamada	help
1382506f1d07SSam Ravnborg	  This device gives processes access to the x86 CPUID instruction to
1383506f1d07SSam Ravnborg	  be executed on a specific processor.  It is a character device
1384506f1d07SSam Ravnborg	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1385506f1d07SSam Ravnborg	  /dev/cpu/31/cpuid.
1386506f1d07SSam Ravnborg
1387506f1d07SSam Ravnborgchoice
1388506f1d07SSam Ravnborg	prompt "High Memory Support"
13896fc108a0SJan Beulich	default HIGHMEM4G
1390506f1d07SSam Ravnborg	depends on X86_32
1391506f1d07SSam Ravnborg
1392506f1d07SSam Ravnborgconfig NOHIGHMEM
1393506f1d07SSam Ravnborg	bool "off"
1394a7f7f624SMasahiro Yamada	help
1395506f1d07SSam Ravnborg	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1396506f1d07SSam Ravnborg	  However, the address space of 32-bit x86 processors is only 4
1397506f1d07SSam Ravnborg	  Gigabytes large. That means that, if you have a large amount of
1398506f1d07SSam Ravnborg	  physical memory, not all of it can be "permanently mapped" by the
1399506f1d07SSam Ravnborg	  kernel. The physical memory that's not permanently mapped is called
1400506f1d07SSam Ravnborg	  "high memory".
1401506f1d07SSam Ravnborg
1402506f1d07SSam Ravnborg	  If you are compiling a kernel which will never run on a machine with
1403506f1d07SSam Ravnborg	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1404506f1d07SSam Ravnborg	  choice and suitable for most users). This will result in a "3GB/1GB"
1405506f1d07SSam Ravnborg	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1406506f1d07SSam Ravnborg	  space and the remaining part of the 4GB virtual memory space is used
1407506f1d07SSam Ravnborg	  by the kernel to permanently map as much physical memory as
1408506f1d07SSam Ravnborg	  possible.
1409506f1d07SSam Ravnborg
1410506f1d07SSam Ravnborg	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1411506f1d07SSam Ravnborg	  answer "4GB" here.
1412506f1d07SSam Ravnborg
1413506f1d07SSam Ravnborg	  If more than 4 Gigabytes is used then answer "64GB" here. This
1414506f1d07SSam Ravnborg	  selection turns Intel PAE (Physical Address Extension) mode on.
1415506f1d07SSam Ravnborg	  PAE implements 3-level paging on IA32 processors. PAE is fully
1416506f1d07SSam Ravnborg	  supported by Linux, PAE mode is implemented on all recent Intel
1417506f1d07SSam Ravnborg	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1418506f1d07SSam Ravnborg	  then the kernel will not boot on CPUs that don't support PAE!
1419506f1d07SSam Ravnborg
1420506f1d07SSam Ravnborg	  The actual amount of total physical memory will either be
1421506f1d07SSam Ravnborg	  auto detected or can be forced by using a kernel command line option
1422506f1d07SSam Ravnborg	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1423506f1d07SSam Ravnborg	  your boot loader (lilo or loadlin) about how to pass options to the
1424506f1d07SSam Ravnborg	  kernel at boot time.)
1425506f1d07SSam Ravnborg
1426506f1d07SSam Ravnborg	  If unsure, say "off".
1427506f1d07SSam Ravnborg
1428506f1d07SSam Ravnborgconfig HIGHMEM4G
1429506f1d07SSam Ravnborg	bool "4GB"
1430a7f7f624SMasahiro Yamada	help
1431506f1d07SSam Ravnborg	  Select this if you have a 32-bit processor and between 1 and 4
1432506f1d07SSam Ravnborg	  gigabytes of physical RAM.
1433506f1d07SSam Ravnborg
1434506f1d07SSam Ravnborgconfig HIGHMEM64G
1435506f1d07SSam Ravnborg	bool "64GB"
143688a2b4edSArnd Bergmann	depends on X86_HAVE_PAE
1437506f1d07SSam Ravnborg	select X86_PAE
1438a7f7f624SMasahiro Yamada	help
1439506f1d07SSam Ravnborg	  Select this if you have a 32-bit processor and more than 4
1440506f1d07SSam Ravnborg	  gigabytes of physical RAM.
1441506f1d07SSam Ravnborg
1442506f1d07SSam Ravnborgendchoice
1443506f1d07SSam Ravnborg
1444506f1d07SSam Ravnborgchoice
14456a108a14SDavid Rientjes	prompt "Memory split" if EXPERT
1446506f1d07SSam Ravnborg	default VMSPLIT_3G
1447506f1d07SSam Ravnborg	depends on X86_32
1448a7f7f624SMasahiro Yamada	help
1449506f1d07SSam Ravnborg	  Select the desired split between kernel and user memory.
1450506f1d07SSam Ravnborg
1451506f1d07SSam Ravnborg	  If the address range available to the kernel is less than the
1452506f1d07SSam Ravnborg	  physical memory installed, the remaining memory will be available
1453506f1d07SSam Ravnborg	  as "high memory". Accessing high memory is a little more costly
1454506f1d07SSam Ravnborg	  than low memory, as it needs to be mapped into the kernel first.
1455506f1d07SSam Ravnborg	  Note that increasing the kernel address space limits the range
1456506f1d07SSam Ravnborg	  available to user programs, making the address space there
1457506f1d07SSam Ravnborg	  tighter.  Selecting anything other than the default 3G/1G split
1458506f1d07SSam Ravnborg	  will also likely make your kernel incompatible with binary-only
1459506f1d07SSam Ravnborg	  kernel modules.
1460506f1d07SSam Ravnborg
1461506f1d07SSam Ravnborg	  If you are not absolutely sure what you are doing, leave this
1462506f1d07SSam Ravnborg	  option alone!
1463506f1d07SSam Ravnborg
1464506f1d07SSam Ravnborg	config VMSPLIT_3G
1465506f1d07SSam Ravnborg		bool "3G/1G user/kernel split"
1466506f1d07SSam Ravnborg	config VMSPLIT_3G_OPT
1467506f1d07SSam Ravnborg		depends on !X86_PAE
1468506f1d07SSam Ravnborg		bool "3G/1G user/kernel split (for full 1G low memory)"
1469506f1d07SSam Ravnborg	config VMSPLIT_2G
1470506f1d07SSam Ravnborg		bool "2G/2G user/kernel split"
1471506f1d07SSam Ravnborg	config VMSPLIT_2G_OPT
1472506f1d07SSam Ravnborg		depends on !X86_PAE
1473506f1d07SSam Ravnborg		bool "2G/2G user/kernel split (for full 2G low memory)"
1474506f1d07SSam Ravnborg	config VMSPLIT_1G
1475506f1d07SSam Ravnborg		bool "1G/3G user/kernel split"
1476506f1d07SSam Ravnborgendchoice
1477506f1d07SSam Ravnborg
1478506f1d07SSam Ravnborgconfig PAGE_OFFSET
1479506f1d07SSam Ravnborg	hex
1480506f1d07SSam Ravnborg	default 0xB0000000 if VMSPLIT_3G_OPT
1481506f1d07SSam Ravnborg	default 0x80000000 if VMSPLIT_2G
1482506f1d07SSam Ravnborg	default 0x78000000 if VMSPLIT_2G_OPT
1483506f1d07SSam Ravnborg	default 0x40000000 if VMSPLIT_1G
1484506f1d07SSam Ravnborg	default 0xC0000000
1485506f1d07SSam Ravnborg	depends on X86_32
1486506f1d07SSam Ravnborg
1487506f1d07SSam Ravnborgconfig HIGHMEM
14883c2362e6SHarvey Harrison	def_bool y
1489506f1d07SSam Ravnborg	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1490506f1d07SSam Ravnborg
1491506f1d07SSam Ravnborgconfig X86_PAE
14929ba16087SJan Beulich	bool "PAE (Physical Address Extension) Support"
149388a2b4edSArnd Bergmann	depends on X86_32 && X86_HAVE_PAE
1494d4a451d5SChristoph Hellwig	select PHYS_ADDR_T_64BIT
14959d99c712SChristian Melki	select SWIOTLB
1496a7f7f624SMasahiro Yamada	help
1497506f1d07SSam Ravnborg	  PAE is required for NX support, and furthermore enables
1498506f1d07SSam Ravnborg	  larger swapspace support for non-overcommit purposes. It
1499506f1d07SSam Ravnborg	  has the cost of more pagetable lookup overhead, and also
1500506f1d07SSam Ravnborg	  consumes more pagetable space per process.
1501506f1d07SSam Ravnborg
150277ef56e4SKirill A. Shutemovconfig X86_5LEVEL
150377ef56e4SKirill A. Shutemov	bool "Enable 5-level page tables support"
150418ec1eafSKirill A. Shutemov	default y
1505eedb92abSKirill A. Shutemov	select DYNAMIC_MEMORY_LAYOUT
1506162434e7SKirill A. Shutemov	select SPARSEMEM_VMEMMAP
150777ef56e4SKirill A. Shutemov	depends on X86_64
1508a7f7f624SMasahiro Yamada	help
150977ef56e4SKirill A. Shutemov	  5-level paging enables access to larger address space:
151077ef56e4SKirill A. Shutemov	  up to 128 PiB of virtual address space and 4 PiB of
151177ef56e4SKirill A. Shutemov	  physical address space.
151277ef56e4SKirill A. Shutemov
151377ef56e4SKirill A. Shutemov	  It will be supported by future Intel CPUs.
151477ef56e4SKirill A. Shutemov
15156657fca0SKirill A. Shutemov	  A kernel with the option enabled can be booted on machines that
15166657fca0SKirill A. Shutemov	  support 4- or 5-level paging.
151777ef56e4SKirill A. Shutemov
1518ff61f079SJonathan Corbet	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
151977ef56e4SKirill A. Shutemov	  information.
152077ef56e4SKirill A. Shutemov
152177ef56e4SKirill A. Shutemov	  Say N if unsure.
152277ef56e4SKirill A. Shutemov
152310971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES
1524e5008abeSLuis R. Rodriguez	def_bool y
15252e1da13fSVlastimil Babka	depends on X86_64
1526a7f7f624SMasahiro Yamada	help
152710971ab2SIngo Molnar	  Certain kernel features effectively disable kernel
152810971ab2SIngo Molnar	  linear 1 GB mappings (even if the CPU otherwise
152910971ab2SIngo Molnar	  supports them), so don't confuse the user by printing
153010971ab2SIngo Molnar	  that we have them enabled.
15319e899816SNick Piggin
15325c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS
15335c280cf6SThomas Gleixner	bool "Enable statistic for Change Page Attribute"
15345c280cf6SThomas Gleixner	depends on DEBUG_FS
1535a7f7f624SMasahiro Yamada	help
1536b75baaf3SIngo Molnar	  Expose statistics about the Change Page Attribute mechanism, which
1537a943245aSColin Ian King	  helps to determine the effectiveness of preserving large and huge
15385c280cf6SThomas Gleixner	  page mappings when mapping protections are changed.
15395c280cf6SThomas Gleixner
154020f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT
154120f07a04SKirill A. Shutemov	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
154220f07a04SKirill A. Shutemov	select DYNAMIC_PHYSICAL_MASK
154320f07a04SKirill A. Shutemov	def_bool n
154420f07a04SKirill A. Shutemov
15457744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT
15467744ccdbSTom Lendacky	bool "AMD Secure Memory Encryption (SME) support"
15477744ccdbSTom Lendacky	depends on X86_64 && CPU_SUP_AMD
15486c321179STom Lendacky	depends on EFI_STUB
154982fef0adSDavid Rientjes	select DMA_COHERENT_POOL
1550ce9084baSArd Biesheuvel	select ARCH_USE_MEMREMAP_PROT
1551597cfe48SJoerg Roedel	select INSTRUCTION_DECODER
1552aa5a4611STom Lendacky	select ARCH_HAS_CC_PLATFORM
155320f07a04SKirill A. Shutemov	select X86_MEM_ENCRYPT
15546c321179STom Lendacky	select UNACCEPTED_MEMORY
1555a7f7f624SMasahiro Yamada	help
15567744ccdbSTom Lendacky	  Say yes to enable support for the encryption of system memory.
15577744ccdbSTom Lendacky	  This requires an AMD processor that supports Secure Memory
15587744ccdbSTom Lendacky	  Encryption (SME).
15597744ccdbSTom Lendacky
1560506f1d07SSam Ravnborg# Common NUMA Features
1561506f1d07SSam Ravnborgconfig NUMA
1562e133f6eaSRandy Dunlap	bool "NUMA Memory Allocation and Scheduler Support"
1563506f1d07SSam Ravnborg	depends on SMP
1564b5660ba7SH. Peter Anvin	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1565b5660ba7SH. Peter Anvin	default y if X86_BIGSMP
15667ecd19cfSKefeng Wang	select USE_PERCPU_NUMA_NODE_ID
15670c436a58SSaurabh Sengar	select OF_NUMA if OF
1568a7f7f624SMasahiro Yamada	help
1569e133f6eaSRandy Dunlap	  Enable NUMA (Non-Uniform Memory Access) support.
1570fd51b2d7SKOSAKI Motohiro
1571506f1d07SSam Ravnborg	  The kernel will try to allocate memory used by a CPU on the
1572506f1d07SSam Ravnborg	  local memory controller of the CPU and add some more
1573506f1d07SSam Ravnborg	  NUMA awareness to the kernel.
1574506f1d07SSam Ravnborg
1575c280ea5eSIngo Molnar	  For 64-bit this is recommended if the system is Intel Core i7
1576fd51b2d7SKOSAKI Motohiro	  (or later), AMD Opteron, or EM64T NUMA.
1577fd51b2d7SKOSAKI Motohiro
1578b5660ba7SH. Peter Anvin	  For 32-bit this is only needed if you boot a 32-bit
15797cf6c945SDavid Rientjes	  kernel on a 64-bit NUMA platform.
1580fd51b2d7SKOSAKI Motohiro
1581fd51b2d7SKOSAKI Motohiro	  Otherwise, you should say N.
1582506f1d07SSam Ravnborg
1583eec1d4faSHans Rosenfeldconfig AMD_NUMA
15843c2362e6SHarvey Harrison	def_bool y
15853c2362e6SHarvey Harrison	prompt "Old style AMD Opteron NUMA detection"
15865da0ef9aSTejun Heo	depends on X86_64 && NUMA && PCI
1587a7f7f624SMasahiro Yamada	help
1588eec1d4faSHans Rosenfeld	  Enable AMD NUMA node topology detection.  You should say Y here if
1589eec1d4faSHans Rosenfeld	  you have a multi processor AMD system. This uses an old method to
1590eec1d4faSHans Rosenfeld	  read the NUMA configuration directly from the builtin Northbridge
1591eec1d4faSHans Rosenfeld	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1592eec1d4faSHans Rosenfeld	  which also takes priority if both are compiled in.
1593506f1d07SSam Ravnborg
1594506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA
15953c2362e6SHarvey Harrison	def_bool y
15963c2362e6SHarvey Harrison	prompt "ACPI NUMA detection"
1597506f1d07SSam Ravnborg	depends on X86_64 && NUMA && ACPI && PCI
1598506f1d07SSam Ravnborg	select ACPI_NUMA
1599a7f7f624SMasahiro Yamada	help
1600506f1d07SSam Ravnborg	  Enable ACPI SRAT based node topology detection.
1601506f1d07SSam Ravnborg
1602506f1d07SSam Ravnborgconfig NUMA_EMU
1603506f1d07SSam Ravnborg	bool "NUMA emulation"
16041b7e03efSTejun Heo	depends on NUMA
1605a7f7f624SMasahiro Yamada	help
1606506f1d07SSam Ravnborg	  Enable NUMA emulation. A flat machine will be split
1607506f1d07SSam Ravnborg	  into virtual nodes when booted with "numa=fake=N", where N is the
1608506f1d07SSam Ravnborg	  number of nodes. This is only useful for debugging.
1609506f1d07SSam Ravnborg
1610506f1d07SSam Ravnborgconfig NODES_SHIFT
1611d25e26b6SLinus Torvalds	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
161251591e31SDavid Rientjes	range 1 10
161351591e31SDavid Rientjes	default "10" if MAXSMP
1614506f1d07SSam Ravnborg	default "6" if X86_64
1615506f1d07SSam Ravnborg	default "3"
1616a9ee6cf5SMike Rapoport	depends on NUMA
1617a7f7f624SMasahiro Yamada	help
16181184dc2fSMike Travis	  Specify the maximum number of NUMA Nodes available on the target
1619692105b8SMatt LaPlante	  system.  Increases memory reserved to accommodate various tables.
1620506f1d07SSam Ravnborg
1621506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE
1622506f1d07SSam Ravnborg	def_bool y
16233b16651fSTejun Heo	depends on X86_32 && !NUMA
1624506f1d07SSam Ravnborg
1625506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE
1626506f1d07SSam Ravnborg	def_bool y
16276ea30386SKees Cook	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1628506f1d07SSam Ravnborg	select SPARSEMEM_STATIC if X86_32
1629506f1d07SSam Ravnborg	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1630506f1d07SSam Ravnborg
16313b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT
16326ad57f7fSMike Rapoport	def_bool X86_64 || (NUMA && X86_32)
16333b16651fSTejun Heo
1634506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL
1635506f1d07SSam Ravnborg	def_bool y
16364eda2bc3SDavid Hildenbrand	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1637506f1d07SSam Ravnborg
1638506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE
1639a0842b70SToshi Kani	bool "Enable sysfs memory/probe interface"
16405c11f00bSDavid Hildenbrand	depends on MEMORY_HOTPLUG
1641a0842b70SToshi Kani	help
1642a0842b70SToshi Kani	  This option enables a sysfs memory/probe interface for testing.
1643cb1aaebeSMauro Carvalho Chehab	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1644a0842b70SToshi Kani	  If you are unsure how to answer this question, answer N.
1645506f1d07SSam Ravnborg
16463b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT
16473b16651fSTejun Heo	def_bool y
16483b16651fSTejun Heo	depends on X86_64 && PROC_KCORE
16493b16651fSTejun Heo
1650a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE
1651a29815a3SAvi Kivity	hex
1652a29815a3SAvi Kivity	default 0 if X86_32
1653a29815a3SAvi Kivity	default 0xdead000000000000 if X86_64
1654a29815a3SAvi Kivity
16557a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE
16567a67832cSDan Williams	bool
16577a67832cSDan Williams
1658ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY
16597a67832cSDan Williams	tristate "Support non-standard NVDIMMs and ADR protected memory"
16609f53f9faSDan Williams	depends on PHYS_ADDR_T_64BIT
16619f53f9faSDan Williams	depends on BLK_DEV
16627a67832cSDan Williams	select X86_PMEM_LEGACY_DEVICE
16637b27a862SDan Williams	select NUMA_KEEP_MEMINFO if NUMA
16649f53f9faSDan Williams	select LIBNVDIMM
1665ec776ef6SChristoph Hellwig	help
1666ec776ef6SChristoph Hellwig	  Treat memory marked using the non-standard e820 type of 12 as used
1667ec776ef6SChristoph Hellwig	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1668ec776ef6SChristoph Hellwig	  The kernel will offer these regions to the 'pmem' driver so
1669ec776ef6SChristoph Hellwig	  they can be used for persistent storage.
1670ec776ef6SChristoph Hellwig
1671ec776ef6SChristoph Hellwig	  Say Y if unsure.
1672ec776ef6SChristoph Hellwig
1673506f1d07SSam Ravnborgconfig HIGHPTE
1674506f1d07SSam Ravnborg	bool "Allocate 3rd-level pagetables from highmem"
16756fc108a0SJan Beulich	depends on HIGHMEM
1676a7f7f624SMasahiro Yamada	help
1677506f1d07SSam Ravnborg	  The VM uses one page table entry for each page of physical memory.
1678506f1d07SSam Ravnborg	  For systems with a lot of RAM, this can be wasteful of precious
1679506f1d07SSam Ravnborg	  low memory.  Setting this option will put user-space page table
1680506f1d07SSam Ravnborg	  entries in high memory.
1681506f1d07SSam Ravnborg
16829f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION
16839f077871SJeremy Fitzhardinge	bool "Check for low memory corruption"
1684a7f7f624SMasahiro Yamada	help
16859f077871SJeremy Fitzhardinge	  Periodically check for memory corruption in low memory, which
16869f077871SJeremy Fitzhardinge	  is suspected to be caused by BIOS.  Even when enabled in the
16879f077871SJeremy Fitzhardinge	  configuration, it is disabled at runtime.  Enable it by
16889f077871SJeremy Fitzhardinge	  setting "memory_corruption_check=1" on the kernel command
16899f077871SJeremy Fitzhardinge	  line.  By default it scans the low 64k of memory every 60
16909f077871SJeremy Fitzhardinge	  seconds; see the memory_corruption_check_size and
16919f077871SJeremy Fitzhardinge	  memory_corruption_check_period parameters in
16928c27ceffSMauro Carvalho Chehab	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
16939f077871SJeremy Fitzhardinge
16949f077871SJeremy Fitzhardinge	  When enabled with the default parameters, this option has
16959f077871SJeremy Fitzhardinge	  almost no overhead, as it reserves a relatively small amount
16969f077871SJeremy Fitzhardinge	  of memory and scans it infrequently.  It both detects corruption
16979f077871SJeremy Fitzhardinge	  and prevents it from affecting the running system.
16989f077871SJeremy Fitzhardinge
16999f077871SJeremy Fitzhardinge	  It is, however, intended as a diagnostic tool; if repeatable
17009f077871SJeremy Fitzhardinge	  BIOS-originated corruption always affects the same memory,
17019f077871SJeremy Fitzhardinge	  you can use memmap= to prevent the kernel from using that
17029f077871SJeremy Fitzhardinge	  memory.
17039f077871SJeremy Fitzhardinge
1704c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1705c885df50SJeremy Fitzhardinge	bool "Set the default setting of memory_corruption_check"
1706c885df50SJeremy Fitzhardinge	depends on X86_CHECK_BIOS_CORRUPTION
1707c885df50SJeremy Fitzhardinge	default y
1708a7f7f624SMasahiro Yamada	help
1709c885df50SJeremy Fitzhardinge	  Set whether the default state of memory_corruption_check is
1710c885df50SJeremy Fitzhardinge	  on or off.
1711c885df50SJeremy Fitzhardinge
1712506f1d07SSam Ravnborgconfig MATH_EMULATION
1713506f1d07SSam Ravnborg	bool
1714a5b9e5a2SAndy Lutomirski	depends on MODIFY_LDT_SYSCALL
171587d6021bSArnd Bergmann	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1716a7f7f624SMasahiro Yamada	help
1717506f1d07SSam Ravnborg	  Linux can emulate a math coprocessor (used for floating point
1718506f1d07SSam Ravnborg	  operations) if you don't have one. 486DX and Pentium processors have
1719506f1d07SSam Ravnborg	  a math coprocessor built in, 486SX and 386 do not, unless you added
1720506f1d07SSam Ravnborg	  a 487DX or 387, respectively. (The messages during boot time can
1721506f1d07SSam Ravnborg	  give you some hints here ["man dmesg"].) Everyone needs either a
1722506f1d07SSam Ravnborg	  coprocessor or this emulation.
1723506f1d07SSam Ravnborg
1724506f1d07SSam Ravnborg	  If you don't have a math coprocessor, you need to say Y here; if you
1725506f1d07SSam Ravnborg	  say Y here even though you have a coprocessor, the coprocessor will
1726506f1d07SSam Ravnborg	  be used nevertheless. (This behavior can be changed with the kernel
1727506f1d07SSam Ravnborg	  command line option "no387", which comes handy if your coprocessor
1728506f1d07SSam Ravnborg	  is broken. Try "man bootparam" or see the documentation of your boot
1729506f1d07SSam Ravnborg	  loader (lilo or loadlin) about how to pass options to the kernel at
1730506f1d07SSam Ravnborg	  boot time.) This means that it is a good idea to say Y here if you
1731506f1d07SSam Ravnborg	  intend to use this kernel on different machines.
1732506f1d07SSam Ravnborg
1733506f1d07SSam Ravnborg	  More information about the internals of the Linux math coprocessor
1734506f1d07SSam Ravnborg	  emulation can be found in <file:arch/x86/math-emu/README>.
1735506f1d07SSam Ravnborg
1736506f1d07SSam Ravnborg	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1737506f1d07SSam Ravnborg	  kernel, it won't hurt.
1738506f1d07SSam Ravnborg
1739506f1d07SSam Ravnborgconfig MTRR
17406fc108a0SJan Beulich	def_bool y
17416a108a14SDavid Rientjes	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1742a7f7f624SMasahiro Yamada	help
1743506f1d07SSam Ravnborg	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1744506f1d07SSam Ravnborg	  the Memory Type Range Registers (MTRRs) may be used to control
1745506f1d07SSam Ravnborg	  processor access to memory ranges. This is most useful if you have
1746506f1d07SSam Ravnborg	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1747506f1d07SSam Ravnborg	  allows bus write transfers to be combined into a larger transfer
1748506f1d07SSam Ravnborg	  before bursting over the PCI/AGP bus. This can increase performance
1749506f1d07SSam Ravnborg	  of image write operations 2.5 times or more. Saying Y here creates a
1750506f1d07SSam Ravnborg	  /proc/mtrr file which may be used to manipulate your processor's
1751506f1d07SSam Ravnborg	  MTRRs. Typically the X server should use this.
1752506f1d07SSam Ravnborg
1753506f1d07SSam Ravnborg	  This code has a reasonably generic interface so that similar
1754506f1d07SSam Ravnborg	  control registers on other processors can be easily supported
1755506f1d07SSam Ravnborg	  as well:
1756506f1d07SSam Ravnborg
1757506f1d07SSam Ravnborg	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1758506f1d07SSam Ravnborg	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1759506f1d07SSam Ravnborg	  these, the ARRs are used to emulate the MTRRs.
1760506f1d07SSam Ravnborg	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1761506f1d07SSam Ravnborg	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1762506f1d07SSam Ravnborg	  write-combining. All of these processors are supported by this code
1763506f1d07SSam Ravnborg	  and it makes sense to say Y here if you have one of them.
1764506f1d07SSam Ravnborg
1765506f1d07SSam Ravnborg	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1766506f1d07SSam Ravnborg	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1767506f1d07SSam Ravnborg	  can lead to all sorts of problems, so it's good to say Y here.
1768506f1d07SSam Ravnborg
1769506f1d07SSam Ravnborg	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1770506f1d07SSam Ravnborg	  just add about 9 KB to your kernel.
1771506f1d07SSam Ravnborg
1772ff61f079SJonathan Corbet	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1773506f1d07SSam Ravnborg
177495ffa243SYinghai Luconfig MTRR_SANITIZER
17752ffb3501SYinghai Lu	def_bool y
177695ffa243SYinghai Lu	prompt "MTRR cleanup support"
177795ffa243SYinghai Lu	depends on MTRR
1778a7f7f624SMasahiro Yamada	help
1779aba3728cSThomas Gleixner	  Convert MTRR layout from continuous to discrete, so X drivers can
1780aba3728cSThomas Gleixner	  add writeback entries.
178195ffa243SYinghai Lu
1782aba3728cSThomas Gleixner	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1783692105b8SMatt LaPlante	  The largest mtrr entry size for a continuous block can be set with
1784aba3728cSThomas Gleixner	  mtrr_chunk_size.
178595ffa243SYinghai Lu
17862ffb3501SYinghai Lu	  If unsure, say Y.
178795ffa243SYinghai Lu
178895ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT
1789f5098d62SYinghai Lu	int "MTRR cleanup enable value (0-1)"
1790f5098d62SYinghai Lu	range 0 1
1791f5098d62SYinghai Lu	default "0"
179295ffa243SYinghai Lu	depends on MTRR_SANITIZER
1793a7f7f624SMasahiro Yamada	help
1794f5098d62SYinghai Lu	  Enable mtrr cleanup default value
179595ffa243SYinghai Lu
179612031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
179712031a62SYinghai Lu	int "MTRR cleanup spare reg num (0-7)"
179812031a62SYinghai Lu	range 0 7
179912031a62SYinghai Lu	default "1"
180012031a62SYinghai Lu	depends on MTRR_SANITIZER
1801a7f7f624SMasahiro Yamada	help
180212031a62SYinghai Lu	  mtrr cleanup spare entries default, it can be changed via
1803aba3728cSThomas Gleixner	  mtrr_spare_reg_nr=N on the kernel command line.
180412031a62SYinghai Lu
18052e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT
18066fc108a0SJan Beulich	def_bool y
18076a108a14SDavid Rientjes	prompt "x86 PAT support" if EXPERT
18082a8a2719SIngo Molnar	depends on MTRR
1809a7f7f624SMasahiro Yamada	help
18102e5d9c85Svenkatesh.pallipadi@intel.com	  Use PAT attributes to setup page level cache control.
1811042b78e4SVenki Pallipadi
18122e5d9c85Svenkatesh.pallipadi@intel.com	  PATs are the modern equivalents of MTRRs and are much more
18132e5d9c85Svenkatesh.pallipadi@intel.com	  flexible than MTRRs.
18142e5d9c85Svenkatesh.pallipadi@intel.com
18152e5d9c85Svenkatesh.pallipadi@intel.com	  Say N here if you see bootup problems (boot crash, boot hang,
1816042b78e4SVenki Pallipadi	  spontaneous reboots) or a non-working video driver.
18172e5d9c85Svenkatesh.pallipadi@intel.com
18182e5d9c85Svenkatesh.pallipadi@intel.com	  If unsure, say Y.
18192e5d9c85Svenkatesh.pallipadi@intel.com
182046cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED
182146cf98cdSVenkatesh Pallipadi	def_bool y
182246cf98cdSVenkatesh Pallipadi	depends on X86_PAT
182346cf98cdSVenkatesh Pallipadi
1824b971880fSBabu Mogerconfig X86_UMIP
1825796ebc81SRicardo Neri	def_bool y
1826b971880fSBabu Moger	prompt "User Mode Instruction Prevention" if EXPERT
1827a7f7f624SMasahiro Yamada	help
1828b971880fSBabu Moger	  User Mode Instruction Prevention (UMIP) is a security feature in
1829b971880fSBabu Moger	  some x86 processors. If enabled, a general protection fault is
1830b971880fSBabu Moger	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1831b971880fSBabu Moger	  executed in user mode. These instructions unnecessarily expose
1832b971880fSBabu Moger	  information about the hardware state.
1833796ebc81SRicardo Neri
1834796ebc81SRicardo Neri	  The vast majority of applications do not use these instructions.
1835796ebc81SRicardo Neri	  For the very few that do, software emulation is provided in
1836796ebc81SRicardo Neri	  specific cases in protected and virtual-8086 modes. Emulated
1837796ebc81SRicardo Neri	  results are dummy.
1838aa35f896SRicardo Neri
1839156ff4a5SPeter Zijlstraconfig CC_HAS_IBT
1840156ff4a5SPeter Zijlstra	# GCC >= 9 and binutils >= 2.29
1841156ff4a5SPeter Zijlstra	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1842156ff4a5SPeter Zijlstra	# Clang/LLVM >= 14
1843262448f3SNathan Chancellor	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1844262448f3SNathan Chancellor	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1845156ff4a5SPeter Zijlstra	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1846262448f3SNathan Chancellor		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1847156ff4a5SPeter Zijlstra		  $(as-instr,endbr64)
1848156ff4a5SPeter Zijlstra
184918e66b69SRick Edgecombeconfig X86_CET
185018e66b69SRick Edgecombe	def_bool n
185118e66b69SRick Edgecombe	help
185218e66b69SRick Edgecombe	  CET features configured (Shadow stack or IBT)
185318e66b69SRick Edgecombe
1854156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT
1855156ff4a5SPeter Zijlstra	prompt "Indirect Branch Tracking"
18564fd5f70cSKees Cook	def_bool y
185703f16cd0SJosh Poimboeuf	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1858f6a2c2b2SNathan Chancellor	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1859f6a2c2b2SNathan Chancellor	depends on !LD_IS_LLD || LLD_VERSION >= 140000
186003f16cd0SJosh Poimboeuf	select OBJTOOL
186118e66b69SRick Edgecombe	select X86_CET
1862156ff4a5SPeter Zijlstra	help
1863156ff4a5SPeter Zijlstra	  Build the kernel with support for Indirect Branch Tracking, a
1864156ff4a5SPeter Zijlstra	  hardware support course-grain forward-edge Control Flow Integrity
1865156ff4a5SPeter Zijlstra	  protection. It enforces that all indirect calls must land on
1866156ff4a5SPeter Zijlstra	  an ENDBR instruction, as such, the compiler will instrument the
1867156ff4a5SPeter Zijlstra	  code with them to make this happen.
1868156ff4a5SPeter Zijlstra
1869ed53a0d9SPeter Zijlstra	  In addition to building the kernel with IBT, seal all functions that
18704cdfc11bSNur Hussein	  are not indirect call targets, avoiding them ever becoming one.
1871ed53a0d9SPeter Zijlstra
1872ed53a0d9SPeter Zijlstra	  This requires LTO like objtool runs and will slow down the build. It
1873ed53a0d9SPeter Zijlstra	  does significantly reduce the number of ENDBR instructions in the
1874ed53a0d9SPeter Zijlstra	  kernel image.
1875ed53a0d9SPeter Zijlstra
187635e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS
187738f3e775SBabu Moger	prompt "Memory Protection Keys"
187835e97790SDave Hansen	def_bool y
1879284244a9SDave Hansen	# Note: only available in 64-bit mode
188038f3e775SBabu Moger	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
188152c8e601SIngo Molnar	select ARCH_USES_HIGH_VMA_FLAGS
188252c8e601SIngo Molnar	select ARCH_HAS_PKEYS
1883a7f7f624SMasahiro Yamada	help
1884284244a9SDave Hansen	  Memory Protection Keys provides a mechanism for enforcing
1885284244a9SDave Hansen	  page-based protections, but without requiring modification of the
1886284244a9SDave Hansen	  page tables when an application changes protection domains.
1887284244a9SDave Hansen
18881eecbcdcSMauro Carvalho Chehab	  For details, see Documentation/core-api/protection-keys.rst
1889284244a9SDave Hansen
1890284244a9SDave Hansen	  If unsure, say y.
189135e97790SDave Hansen
1892db616173SMichal Hockochoice
1893db616173SMichal Hocko	prompt "TSX enable mode"
1894db616173SMichal Hocko	depends on CPU_SUP_INTEL
1895db616173SMichal Hocko	default X86_INTEL_TSX_MODE_OFF
1896db616173SMichal Hocko	help
1897db616173SMichal Hocko	  Intel's TSX (Transactional Synchronization Extensions) feature
1898db616173SMichal Hocko	  allows to optimize locking protocols through lock elision which
1899db616173SMichal Hocko	  can lead to a noticeable performance boost.
1900db616173SMichal Hocko
1901db616173SMichal Hocko	  On the other hand it has been shown that TSX can be exploited
1902db616173SMichal Hocko	  to form side channel attacks (e.g. TAA) and chances are there
1903db616173SMichal Hocko	  will be more of those attacks discovered in the future.
1904db616173SMichal Hocko
1905db616173SMichal Hocko	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1906db616173SMichal Hocko	  might override this decision by tsx=on the command line parameter.
1907db616173SMichal Hocko	  Even with TSX enabled, the kernel will attempt to enable the best
1908db616173SMichal Hocko	  possible TAA mitigation setting depending on the microcode available
1909db616173SMichal Hocko	  for the particular machine.
1910db616173SMichal Hocko
1911db616173SMichal Hocko	  This option allows to set the default tsx mode between tsx=on, =off
1912db616173SMichal Hocko	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1913db616173SMichal Hocko	  details.
1914db616173SMichal Hocko
1915db616173SMichal Hocko	  Say off if not sure, auto if TSX is in use but it should be used on safe
1916db616173SMichal Hocko	  platforms or on if TSX is in use and the security aspect of tsx is not
1917db616173SMichal Hocko	  relevant.
1918db616173SMichal Hocko
1919db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF
1920db616173SMichal Hocko	bool "off"
1921db616173SMichal Hocko	help
1922db616173SMichal Hocko	  TSX is disabled if possible - equals to tsx=off command line parameter.
1923db616173SMichal Hocko
1924db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON
1925db616173SMichal Hocko	bool "on"
1926db616173SMichal Hocko	help
1927db616173SMichal Hocko	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1928db616173SMichal Hocko	  line parameter.
1929db616173SMichal Hocko
1930db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO
1931db616173SMichal Hocko	bool "auto"
1932db616173SMichal Hocko	help
1933db616173SMichal Hocko	  TSX is enabled on TSX capable HW that is believed to be safe against
1934db616173SMichal Hocko	  side channel attacks- equals the tsx=auto command line parameter.
1935db616173SMichal Hockoendchoice
1936db616173SMichal Hocko
1937e7e05452SSean Christophersonconfig X86_SGX
1938e7e05452SSean Christopherson	bool "Software Guard eXtensions (SGX)"
1939b8d1d163SDaniel Sneddon	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1940e7e05452SSean Christopherson	depends on CRYPTO=y
1941e7e05452SSean Christopherson	depends on CRYPTO_SHA256=y
1942e7e05452SSean Christopherson	select MMU_NOTIFIER
1943901ddbb9SJarkko Sakkinen	select NUMA_KEEP_MEMINFO if NUMA
194440e0e784STony Luck	select XARRAY_MULTI
1945e7e05452SSean Christopherson	help
1946e7e05452SSean Christopherson	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1947e7e05452SSean Christopherson	  that can be used by applications to set aside private regions of code
1948e7e05452SSean Christopherson	  and data, referred to as enclaves. An enclave's private memory can
1949e7e05452SSean Christopherson	  only be accessed by code running within the enclave. Accesses from
1950e7e05452SSean Christopherson	  outside the enclave, including other enclaves, are disallowed by
1951e7e05452SSean Christopherson	  hardware.
1952e7e05452SSean Christopherson
1953e7e05452SSean Christopherson	  If unsure, say N.
1954e7e05452SSean Christopherson
195518e66b69SRick Edgecombeconfig X86_USER_SHADOW_STACK
195618e66b69SRick Edgecombe	bool "X86 userspace shadow stack"
195718e66b69SRick Edgecombe	depends on AS_WRUSS
195818e66b69SRick Edgecombe	depends on X86_64
195918e66b69SRick Edgecombe	select ARCH_USES_HIGH_VMA_FLAGS
196018e66b69SRick Edgecombe	select X86_CET
196118e66b69SRick Edgecombe	help
196218e66b69SRick Edgecombe	  Shadow stack protection is a hardware feature that detects function
196318e66b69SRick Edgecombe	  return address corruption.  This helps mitigate ROP attacks.
196418e66b69SRick Edgecombe	  Applications must be enabled to use it, and old userspace does not
196518e66b69SRick Edgecombe	  get protection "for free".
196618e66b69SRick Edgecombe
196718e66b69SRick Edgecombe	  CPUs supporting shadow stacks were first released in 2020.
196818e66b69SRick Edgecombe
196954acee60SDave Hansen	  See Documentation/arch/x86/shstk.rst for more information.
197018e66b69SRick Edgecombe
197118e66b69SRick Edgecombe	  If unsure, say N.
197218e66b69SRick Edgecombe
1973c33621b4SKai Huangconfig INTEL_TDX_HOST
1974c33621b4SKai Huang	bool "Intel Trust Domain Extensions (TDX) host support"
1975c33621b4SKai Huang	depends on CPU_SUP_INTEL
1976c33621b4SKai Huang	depends on X86_64
1977c33621b4SKai Huang	depends on KVM_INTEL
19783115cabdSKai Huang	depends on X86_X2APIC
1979abe8dbabSKai Huang	select ARCH_KEEP_MEMBLOCK
1980ac3a2208SKai Huang	depends on CONTIG_ALLOC
1981cb8eb06dSDave Hansen	depends on !KEXEC_CORE
198283e1bdc9SKai Huang	depends on X86_MCE
1983c33621b4SKai Huang	help
1984c33621b4SKai Huang	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1985c33621b4SKai Huang	  host and certain physical attacks.  This option enables necessary TDX
1986c33621b4SKai Huang	  support in the host kernel to run confidential VMs.
1987c33621b4SKai Huang
1988c33621b4SKai Huang	  If unsure, say N.
1989c33621b4SKai Huang
1990506f1d07SSam Ravnborgconfig EFI
19919ba16087SJan Beulich	bool "EFI runtime service support"
19925b83683fSHuang, Ying	depends on ACPI
1993f6ce5002SSergey Vlasov	select UCS2_STRING
1994022ee6c5SArd Biesheuvel	select EFI_RUNTIME_WRAPPERS
19951ff2fc02STom Lendacky	select ARCH_USE_MEMREMAP_PROT
1996aba7e066SArd Biesheuvel	select EFI_RUNTIME_MAP if KEXEC_CORE
1997a7f7f624SMasahiro Yamada	help
19988b2cb7a8SHuang, Ying	  This enables the kernel to use EFI runtime services that are
1999506f1d07SSam Ravnborg	  available (such as the EFI variable services).
2000506f1d07SSam Ravnborg
20018b2cb7a8SHuang, Ying	  This option is only useful on systems that have EFI firmware.
20028b2cb7a8SHuang, Ying	  In addition, you should use the latest ELILO loader available
20038b2cb7a8SHuang, Ying	  at <http://elilo.sourceforge.net> in order to take advantage
20048b2cb7a8SHuang, Ying	  of EFI runtime services. However, even with this option, the
20058b2cb7a8SHuang, Ying	  resultant kernel should continue to boot on existing non-EFI
20068b2cb7a8SHuang, Ying	  platforms.
2007506f1d07SSam Ravnborg
2008291f3632SMatt Flemingconfig EFI_STUB
2009291f3632SMatt Fleming	bool "EFI stub support"
2010c6dbd3e5SPeter Zijlstra	depends on EFI
20117b2a583aSMatt Fleming	select RELOCATABLE
2012a7f7f624SMasahiro Yamada	help
2013291f3632SMatt Fleming	  This kernel feature allows a bzImage to be loaded directly
2014291f3632SMatt Fleming	  by EFI firmware without the use of a bootloader.
2015291f3632SMatt Fleming
20164f4cfa6cSMauro Carvalho Chehab	  See Documentation/admin-guide/efi-stub.rst for more information.
20170c759662SMatt Fleming
2018cc3fdda2SArd Biesheuvelconfig EFI_HANDOVER_PROTOCOL
2019cc3fdda2SArd Biesheuvel	bool "EFI handover protocol (DEPRECATED)"
2020cc3fdda2SArd Biesheuvel	depends on EFI_STUB
2021cc3fdda2SArd Biesheuvel	default y
2022cc3fdda2SArd Biesheuvel	help
2023cc3fdda2SArd Biesheuvel	  Select this in order to include support for the deprecated EFI
2024cc3fdda2SArd Biesheuvel	  handover protocol, which defines alternative entry points into the
2025cc3fdda2SArd Biesheuvel	  EFI stub.  This is a practice that has no basis in the UEFI
2026cc3fdda2SArd Biesheuvel	  specification, and requires a priori knowledge on the part of the
2027cc3fdda2SArd Biesheuvel	  bootloader about Linux/x86 specific ways of passing the command line
2028cc3fdda2SArd Biesheuvel	  and initrd, and where in memory those assets may be loaded.
2029cc3fdda2SArd Biesheuvel
2030cc3fdda2SArd Biesheuvel	  If in doubt, say Y. Even though the corresponding support is not
2031cc3fdda2SArd Biesheuvel	  present in upstream GRUB or other bootloaders, most distros build
2032cc3fdda2SArd Biesheuvel	  GRUB with numerous downstream patches applied, and may rely on the
2033cc3fdda2SArd Biesheuvel	  handover protocol as as result.
2034cc3fdda2SArd Biesheuvel
20357d453eeeSMatt Flemingconfig EFI_MIXED
20367d453eeeSMatt Fleming	bool "EFI mixed-mode support"
20377d453eeeSMatt Fleming	depends on EFI_STUB && X86_64
2038a7f7f624SMasahiro Yamada	help
20397d453eeeSMatt Fleming	  Enabling this feature allows a 64-bit kernel to be booted
20407d453eeeSMatt Fleming	  on a 32-bit firmware, provided that your CPU supports 64-bit
20417d453eeeSMatt Fleming	  mode.
20427d453eeeSMatt Fleming
20437d453eeeSMatt Fleming	  Note that it is not possible to boot a mixed-mode enabled
20447d453eeeSMatt Fleming	  kernel via the EFI boot stub - a bootloader that supports
20457d453eeeSMatt Fleming	  the EFI handover protocol must be used.
20467d453eeeSMatt Fleming
20477d453eeeSMatt Fleming	  If unsure, say N.
20487d453eeeSMatt Fleming
20494059ba65SArd Biesheuvelconfig EFI_FAKE_MEMMAP
20504059ba65SArd Biesheuvel	bool "Enable EFI fake memory map"
20514059ba65SArd Biesheuvel	depends on EFI
20524059ba65SArd Biesheuvel	help
20534059ba65SArd Biesheuvel	  Saying Y here will enable "efi_fake_mem" boot option.  By specifying
20544059ba65SArd Biesheuvel	  this parameter, you can add arbitrary attribute to specific memory
20554059ba65SArd Biesheuvel	  range by updating original (firmware provided) EFI memmap.  This is
20564059ba65SArd Biesheuvel	  useful for debugging of EFI memmap related feature, e.g., Address
20574059ba65SArd Biesheuvel	  Range Mirroring feature.
20584059ba65SArd Biesheuvel
20594059ba65SArd Biesheuvelconfig EFI_MAX_FAKE_MEM
20604059ba65SArd Biesheuvel	int "maximum allowable number of ranges in efi_fake_mem boot option"
20614059ba65SArd Biesheuvel	depends on EFI_FAKE_MEMMAP
20624059ba65SArd Biesheuvel	range 1 128
20634059ba65SArd Biesheuvel	default 8
20644059ba65SArd Biesheuvel	help
20654059ba65SArd Biesheuvel	  Maximum allowable number of ranges in efi_fake_mem boot option.
20664059ba65SArd Biesheuvel	  Ranges can be set up to this value using comma-separated list.
20674059ba65SArd Biesheuvel	  The default value is 8.
20684059ba65SArd Biesheuvel
20691fff234dSArd Biesheuvelconfig EFI_RUNTIME_MAP
20701fff234dSArd Biesheuvel	bool "Export EFI runtime maps to sysfs" if EXPERT
20711fff234dSArd Biesheuvel	depends on EFI
20721fff234dSArd Biesheuvel	help
20731fff234dSArd Biesheuvel	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
20741fff234dSArd Biesheuvel	  That memory map is required by the 2nd kernel to set up EFI virtual
20751fff234dSArd Biesheuvel	  mappings after kexec, but can also be used for debugging purposes.
20761fff234dSArd Biesheuvel
20771fff234dSArd Biesheuvel	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
20781fff234dSArd Biesheuvel
20798636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz"
2080506f1d07SSam Ravnborg
20816af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC
20826af51380SEric DeVolder	def_bool y
2083506f1d07SSam Ravnborg
20846af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_FILE
2085c1ad12eeSArnd Bergmann	def_bool X86_64
2086506f1d07SSam Ravnborg
20876af51380SEric DeVolderconfig ARCH_SELECTS_KEXEC_FILE
20886af51380SEric DeVolder	def_bool y
20896af51380SEric DeVolder	depends on KEXEC_FILE
2090b69a2afdSJonathan McDowell	select HAVE_IMA_KEXEC if IMA
209174ca317cSVivek Goyal
2092e6265fe7SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_PURGATORY
2093c1ad12eeSArnd Bergmann	def_bool y
2094b799a09fSAKASHI Takahiro
20956af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_SIG
20966af51380SEric DeVolder	def_bool y
209799d5cadfSJiri Bohac
20986af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_SIG_FORCE
20996af51380SEric DeVolder	def_bool y
210099d5cadfSJiri Bohac
21016af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
21026af51380SEric DeVolder	def_bool y
210399d5cadfSJiri Bohac
21046af51380SEric DeVolderconfig ARCH_SUPPORTS_KEXEC_JUMP
21056af51380SEric DeVolder	def_bool y
21068e7d8381SVivek Goyal
21076af51380SEric DeVolderconfig ARCH_SUPPORTS_CRASH_DUMP
21086af51380SEric DeVolder	def_bool X86_64 || (X86_32 && HIGHMEM)
21098e7d8381SVivek Goyal
2110ea53ad9cSEric DeVolderconfig ARCH_SUPPORTS_CRASH_HOTPLUG
2111ea53ad9cSEric DeVolder	def_bool y
21123ab83521SHuang Ying
21139c08a2a1SBaoquan Heconfig ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
211485fcde40SBaoquan He	def_bool CRASH_RESERVE
21159c08a2a1SBaoquan He
2116506f1d07SSam Ravnborgconfig PHYSICAL_START
21176a108a14SDavid Rientjes	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2118ceefccc9SH. Peter Anvin	default "0x1000000"
2119a7f7f624SMasahiro Yamada	help
2120506f1d07SSam Ravnborg	  This gives the physical address where the kernel is loaded.
2121506f1d07SSam Ravnborg
212243b1d3e6SChris Koch	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
212343b1d3e6SChris Koch	  will decompress itself to above physical address and run from there.
212443b1d3e6SChris Koch	  Otherwise, bzImage will run from the address where it has been loaded
212543b1d3e6SChris Koch	  by the boot loader. The only exception is if it is loaded below the
212643b1d3e6SChris Koch	  above physical address, in which case it will relocate itself there.
2127506f1d07SSam Ravnborg
2128506f1d07SSam Ravnborg	  In normal kdump cases one does not have to set/change this option
2129506f1d07SSam Ravnborg	  as now bzImage can be compiled as a completely relocatable image
2130506f1d07SSam Ravnborg	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2131506f1d07SSam Ravnborg	  address. This option is mainly useful for the folks who don't want
2132506f1d07SSam Ravnborg	  to use a bzImage for capturing the crash dump and want to use a
2133506f1d07SSam Ravnborg	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2134506f1d07SSam Ravnborg	  to be specifically compiled to run from a specific memory area
2135506f1d07SSam Ravnborg	  (normally a reserved region) and this option comes handy.
2136506f1d07SSam Ravnborg
2137ceefccc9SH. Peter Anvin	  So if you are using bzImage for capturing the crash dump,
2138ceefccc9SH. Peter Anvin	  leave the value here unchanged to 0x1000000 and set
2139ceefccc9SH. Peter Anvin	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2140ceefccc9SH. Peter Anvin	  for capturing the crash dump change this value to start of
2141ceefccc9SH. Peter Anvin	  the reserved region.  In other words, it can be set based on
2142ceefccc9SH. Peter Anvin	  the "X" value as specified in the "crashkernel=YM@XM"
2143ceefccc9SH. Peter Anvin	  command line boot parameter passed to the panic-ed
2144330d4810SMauro Carvalho Chehab	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2145ceefccc9SH. Peter Anvin	  for more details about crash dumps.
2146506f1d07SSam Ravnborg
2147506f1d07SSam Ravnborg	  Usage of bzImage for capturing the crash dump is recommended as
2148506f1d07SSam Ravnborg	  one does not have to build two kernels. Same kernel can be used
2149506f1d07SSam Ravnborg	  as production kernel and capture kernel. Above option should have
2150506f1d07SSam Ravnborg	  gone away after relocatable bzImage support is introduced. But it
2151506f1d07SSam Ravnborg	  is present because there are users out there who continue to use
2152506f1d07SSam Ravnborg	  vmlinux for dump capture. This option should go away down the
2153506f1d07SSam Ravnborg	  line.
2154506f1d07SSam Ravnborg
2155506f1d07SSam Ravnborg	  Don't change this unless you know what you are doing.
2156506f1d07SSam Ravnborg
2157506f1d07SSam Ravnborgconfig RELOCATABLE
215826717808SH. Peter Anvin	bool "Build a relocatable kernel"
215926717808SH. Peter Anvin	default y
2160a7f7f624SMasahiro Yamada	help
2161506f1d07SSam Ravnborg	  This builds a kernel image that retains relocation information
2162506f1d07SSam Ravnborg	  so it can be loaded someplace besides the default 1MB.
2163506f1d07SSam Ravnborg	  The relocations tend to make the kernel binary about 10% larger,
2164506f1d07SSam Ravnborg	  but are discarded at runtime.
2165506f1d07SSam Ravnborg
2166506f1d07SSam Ravnborg	  One use is for the kexec on panic case where the recovery kernel
2167506f1d07SSam Ravnborg	  must live at a different physical address than the primary
2168506f1d07SSam Ravnborg	  kernel.
2169506f1d07SSam Ravnborg
2170506f1d07SSam Ravnborg	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2171506f1d07SSam Ravnborg	  it has been loaded at and the compile time physical address
21728ab3820fSKees Cook	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2173506f1d07SSam Ravnborg
21748ab3820fSKees Cookconfig RANDOMIZE_BASE
2175e8581e3dSBaoquan He	bool "Randomize the address of the kernel image (KASLR)"
21768ab3820fSKees Cook	depends on RELOCATABLE
21776807c846SIngo Molnar	default y
2178a7f7f624SMasahiro Yamada	help
2179e8581e3dSBaoquan He	  In support of Kernel Address Space Layout Randomization (KASLR),
2180e8581e3dSBaoquan He	  this randomizes the physical address at which the kernel image
2181e8581e3dSBaoquan He	  is decompressed and the virtual address where the kernel
2182e8581e3dSBaoquan He	  image is mapped, as a security feature that deters exploit
2183e8581e3dSBaoquan He	  attempts relying on knowledge of the location of kernel
2184e8581e3dSBaoquan He	  code internals.
2185e8581e3dSBaoquan He
2186ed9f007eSKees Cook	  On 64-bit, the kernel physical and virtual addresses are
2187ed9f007eSKees Cook	  randomized separately. The physical address will be anywhere
2188ed9f007eSKees Cook	  between 16MB and the top of physical memory (up to 64TB). The
2189ed9f007eSKees Cook	  virtual address will be randomized from 16MB up to 1GB (9 bits
2190ed9f007eSKees Cook	  of entropy). Note that this also reduces the memory space
2191ed9f007eSKees Cook	  available to kernel modules from 1.5GB to 1GB.
2192ed9f007eSKees Cook
2193ed9f007eSKees Cook	  On 32-bit, the kernel physical and virtual addresses are
2194ed9f007eSKees Cook	  randomized together. They will be randomized from 16MB up to
2195ed9f007eSKees Cook	  512MB (8 bits of entropy).
21968ab3820fSKees Cook
2197a653f356SKees Cook	  Entropy is generated using the RDRAND instruction if it is
2198e8581e3dSBaoquan He	  supported. If RDTSC is supported, its value is mixed into
2199e8581e3dSBaoquan He	  the entropy pool as well. If neither RDRAND nor RDTSC are
2200ed9f007eSKees Cook	  supported, then entropy is read from the i8254 timer. The
2201ed9f007eSKees Cook	  usable entropy is limited by the kernel being built using
2202ed9f007eSKees Cook	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2203ed9f007eSKees Cook	  minimum of 2MB. As a result, only 10 bits of entropy are
2204ed9f007eSKees Cook	  theoretically possible, but the implementations are further
2205ed9f007eSKees Cook	  limited due to memory layouts.
2206e8581e3dSBaoquan He
22076807c846SIngo Molnar	  If unsure, say Y.
2208da2b6fb9SKees Cook
22098ab3820fSKees Cook# Relocation on x86 needs some additional build support
2210845adf72SH. Peter Anvinconfig X86_NEED_RELOCS
2211845adf72SH. Peter Anvin	def_bool y
22128ab3820fSKees Cook	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2213845adf72SH. Peter Anvin
2214506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN
2215a0215061SKees Cook	hex "Alignment value to which kernel should be aligned"
22168ab3820fSKees Cook	default "0x200000"
2217a0215061SKees Cook	range 0x2000 0x1000000 if X86_32
2218a0215061SKees Cook	range 0x200000 0x1000000 if X86_64
2219a7f7f624SMasahiro Yamada	help
2220506f1d07SSam Ravnborg	  This value puts the alignment restrictions on physical address
2221506f1d07SSam Ravnborg	  where kernel is loaded and run from. Kernel is compiled for an
2222506f1d07SSam Ravnborg	  address which meets above alignment restriction.
2223506f1d07SSam Ravnborg
2224506f1d07SSam Ravnborg	  If bootloader loads the kernel at a non-aligned address and
2225506f1d07SSam Ravnborg	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2226506f1d07SSam Ravnborg	  address aligned to above value and run from there.
2227506f1d07SSam Ravnborg
2228506f1d07SSam Ravnborg	  If bootloader loads the kernel at a non-aligned address and
2229506f1d07SSam Ravnborg	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2230506f1d07SSam Ravnborg	  load address and decompress itself to the address it has been
2231506f1d07SSam Ravnborg	  compiled for and run from there. The address for which kernel is
2232506f1d07SSam Ravnborg	  compiled already meets above alignment restrictions. Hence the
2233506f1d07SSam Ravnborg	  end result is that kernel runs from a physical address meeting
2234506f1d07SSam Ravnborg	  above alignment restrictions.
2235506f1d07SSam Ravnborg
2236a0215061SKees Cook	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2237a0215061SKees Cook	  this value must be a multiple of 0x200000.
2238a0215061SKees Cook
2239506f1d07SSam Ravnborg	  Don't change this unless you know what you are doing.
2240506f1d07SSam Ravnborg
2241eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT
2242eedb92abSKirill A. Shutemov	bool
2243a7f7f624SMasahiro Yamada	help
2244eedb92abSKirill A. Shutemov	  This option makes base addresses of vmalloc and vmemmap as well as
2245eedb92abSKirill A. Shutemov	  __PAGE_OFFSET movable during boot.
2246eedb92abSKirill A. Shutemov
22470483e1faSThomas Garnierconfig RANDOMIZE_MEMORY
22480483e1faSThomas Garnier	bool "Randomize the kernel memory sections"
22490483e1faSThomas Garnier	depends on X86_64
22500483e1faSThomas Garnier	depends on RANDOMIZE_BASE
2251eedb92abSKirill A. Shutemov	select DYNAMIC_MEMORY_LAYOUT
22520483e1faSThomas Garnier	default RANDOMIZE_BASE
2253a7f7f624SMasahiro Yamada	help
22540483e1faSThomas Garnier	  Randomizes the base virtual address of kernel memory sections
22550483e1faSThomas Garnier	  (physical memory mapping, vmalloc & vmemmap). This security feature
22560483e1faSThomas Garnier	  makes exploits relying on predictable memory locations less reliable.
22570483e1faSThomas Garnier
22580483e1faSThomas Garnier	  The order of allocations remains unchanged. Entropy is generated in
22590483e1faSThomas Garnier	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
22600483e1faSThomas Garnier	  configuration have in average 30,000 different possible virtual
22610483e1faSThomas Garnier	  addresses for each memory section.
22620483e1faSThomas Garnier
22636807c846SIngo Molnar	  If unsure, say Y.
22640483e1faSThomas Garnier
226590397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING
226690397a41SThomas Garnier	hex "Physical memory mapping padding" if EXPERT
226790397a41SThomas Garnier	depends on RANDOMIZE_MEMORY
226890397a41SThomas Garnier	default "0xa" if MEMORY_HOTPLUG
226990397a41SThomas Garnier	default "0x0"
227090397a41SThomas Garnier	range 0x1 0x40 if MEMORY_HOTPLUG
227190397a41SThomas Garnier	range 0x0 0x40
2272a7f7f624SMasahiro Yamada	help
227390397a41SThomas Garnier	  Define the padding in terabytes added to the existing physical
227490397a41SThomas Garnier	  memory size during kernel memory randomization. It is useful
227590397a41SThomas Garnier	  for memory hotplug support but reduces the entropy available for
227690397a41SThomas Garnier	  address randomization.
227790397a41SThomas Garnier
227890397a41SThomas Garnier	  If unsure, leave at the default value.
227990397a41SThomas Garnier
22806449dcb0SKirill A. Shutemovconfig ADDRESS_MASKING
22816449dcb0SKirill A. Shutemov	bool "Linear Address Masking support"
22826449dcb0SKirill A. Shutemov	depends on X86_64
22836449dcb0SKirill A. Shutemov	help
22846449dcb0SKirill A. Shutemov	  Linear Address Masking (LAM) modifies the checking that is applied
22856449dcb0SKirill A. Shutemov	  to 64-bit linear addresses, allowing software to use of the
22866449dcb0SKirill A. Shutemov	  untranslated address bits for metadata.
22876449dcb0SKirill A. Shutemov
22886449dcb0SKirill A. Shutemov	  The capability can be used for efficient address sanitizers (ASAN)
22896449dcb0SKirill A. Shutemov	  implementation and for optimizations in JITs.
22906449dcb0SKirill A. Shutemov
2291506f1d07SSam Ravnborgconfig HOTPLUG_CPU
2292bebd024eSThomas Gleixner	def_bool y
229340b31360SStephen Rothwell	depends on SMP
2294506f1d07SSam Ravnborg
2295506f1d07SSam Ravnborgconfig COMPAT_VDSO
2296b0b49f26SAndy Lutomirski	def_bool n
2297b0b49f26SAndy Lutomirski	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2298953fee1dSIngo Molnar	depends on COMPAT_32
2299a7f7f624SMasahiro Yamada	help
2300b0b49f26SAndy Lutomirski	  Certain buggy versions of glibc will crash if they are
2301b0b49f26SAndy Lutomirski	  presented with a 32-bit vDSO that is not mapped at the address
2302b0b49f26SAndy Lutomirski	  indicated in its segment table.
2303e84446deSRandy Dunlap
2304b0b49f26SAndy Lutomirski	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2305b0b49f26SAndy Lutomirski	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2306b0b49f26SAndy Lutomirski	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2307b0b49f26SAndy Lutomirski	  the only released version with the bug, but OpenSUSE 9
2308b0b49f26SAndy Lutomirski	  contains a buggy "glibc 2.3.2".
2309506f1d07SSam Ravnborg
2310b0b49f26SAndy Lutomirski	  The symptom of the bug is that everything crashes on startup, saying:
2311b0b49f26SAndy Lutomirski	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2312b0b49f26SAndy Lutomirski
2313b0b49f26SAndy Lutomirski	  Saying Y here changes the default value of the vdso32 boot
2314b0b49f26SAndy Lutomirski	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2315b0b49f26SAndy Lutomirski	  This works around the glibc bug but hurts performance.
2316b0b49f26SAndy Lutomirski
2317b0b49f26SAndy Lutomirski	  If unsure, say N: if you are compiling your own kernel, you
2318b0b49f26SAndy Lutomirski	  are unlikely to be using a buggy version of glibc.
2319506f1d07SSam Ravnborg
23203dc33bd3SKees Cookchoice
23213dc33bd3SKees Cook	prompt "vsyscall table for legacy applications"
23223dc33bd3SKees Cook	depends on X86_64
2323625b7b7fSAndy Lutomirski	default LEGACY_VSYSCALL_XONLY
23243dc33bd3SKees Cook	help
23253dc33bd3SKees Cook	  Legacy user code that does not know how to find the vDSO expects
23263dc33bd3SKees Cook	  to be able to issue three syscalls by calling fixed addresses in
23273dc33bd3SKees Cook	  kernel space. Since this location is not randomized with ASLR,
23283dc33bd3SKees Cook	  it can be used to assist security vulnerability exploitation.
23293dc33bd3SKees Cook
23303dc33bd3SKees Cook	  This setting can be changed at boot time via the kernel command
2331bf00745eSAndy Lutomirski	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2332bf00745eSAndy Lutomirski	  is deprecated and can only be enabled using the kernel command
2333bf00745eSAndy Lutomirski	  line.
23343dc33bd3SKees Cook
23353dc33bd3SKees Cook	  On a system with recent enough glibc (2.14 or newer) and no
23363dc33bd3SKees Cook	  static binaries, you can say None without a performance penalty
23373dc33bd3SKees Cook	  to improve security.
23383dc33bd3SKees Cook
2339bd49e16eSAndy Lutomirski	  If unsure, select "Emulate execution only".
23403dc33bd3SKees Cook
2341bd49e16eSAndy Lutomirski	config LEGACY_VSYSCALL_XONLY
2342bd49e16eSAndy Lutomirski		bool "Emulate execution only"
2343bd49e16eSAndy Lutomirski		help
2344bd49e16eSAndy Lutomirski		  The kernel traps and emulates calls into the fixed vsyscall
2345bd49e16eSAndy Lutomirski		  address mapping and does not allow reads.  This
2346bd49e16eSAndy Lutomirski		  configuration is recommended when userspace might use the
2347bd49e16eSAndy Lutomirski		  legacy vsyscall area but support for legacy binary
2348bd49e16eSAndy Lutomirski		  instrumentation of legacy code is not needed.  It mitigates
2349bd49e16eSAndy Lutomirski		  certain uses of the vsyscall area as an ASLR-bypassing
2350bd49e16eSAndy Lutomirski		  buffer.
23513dc33bd3SKees Cook
23523dc33bd3SKees Cook	config LEGACY_VSYSCALL_NONE
23533dc33bd3SKees Cook		bool "None"
23543dc33bd3SKees Cook		help
23553dc33bd3SKees Cook		  There will be no vsyscall mapping at all. This will
23563dc33bd3SKees Cook		  eliminate any risk of ASLR bypass due to the vsyscall
23573dc33bd3SKees Cook		  fixed address mapping. Attempts to use the vsyscalls
23583dc33bd3SKees Cook		  will be reported to dmesg, so that either old or
23593dc33bd3SKees Cook		  malicious userspace programs can be identified.
23603dc33bd3SKees Cook
23613dc33bd3SKees Cookendchoice
23623dc33bd3SKees Cook
2363516cbf37STim Birdconfig CMDLINE_BOOL
2364516cbf37STim Bird	bool "Built-in kernel command line"
2365a7f7f624SMasahiro Yamada	help
2366516cbf37STim Bird	  Allow for specifying boot arguments to the kernel at
2367516cbf37STim Bird	  build time.  On some systems (e.g. embedded ones), it is
2368516cbf37STim Bird	  necessary or convenient to provide some or all of the
2369516cbf37STim Bird	  kernel boot arguments with the kernel itself (that is,
2370516cbf37STim Bird	  to not rely on the boot loader to provide them.)
2371516cbf37STim Bird
2372516cbf37STim Bird	  To compile command line arguments into the kernel,
2373516cbf37STim Bird	  set this option to 'Y', then fill in the
237469711ca1SSébastien Hinderer	  boot arguments in CONFIG_CMDLINE.
2375516cbf37STim Bird
2376516cbf37STim Bird	  Systems with fully functional boot loaders (i.e. non-embedded)
2377516cbf37STim Bird	  should leave this option set to 'N'.
2378516cbf37STim Bird
2379516cbf37STim Birdconfig CMDLINE
2380516cbf37STim Bird	string "Built-in kernel command string"
2381516cbf37STim Bird	depends on CMDLINE_BOOL
2382516cbf37STim Bird	default ""
2383a7f7f624SMasahiro Yamada	help
2384516cbf37STim Bird	  Enter arguments here that should be compiled into the kernel
2385516cbf37STim Bird	  image and used at boot time.  If the boot loader provides a
2386516cbf37STim Bird	  command line at boot time, it is appended to this string to
2387516cbf37STim Bird	  form the full kernel command line, when the system boots.
2388516cbf37STim Bird
2389516cbf37STim Bird	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2390516cbf37STim Bird	  change this behavior.
2391516cbf37STim Bird
2392516cbf37STim Bird	  In most cases, the command line (whether built-in or provided
2393516cbf37STim Bird	  by the boot loader) should specify the device for the root
2394516cbf37STim Bird	  file system.
2395516cbf37STim Bird
2396516cbf37STim Birdconfig CMDLINE_OVERRIDE
2397516cbf37STim Bird	bool "Built-in command line overrides boot loader arguments"
2398645e6466SAnders Roxell	depends on CMDLINE_BOOL && CMDLINE != ""
2399a7f7f624SMasahiro Yamada	help
2400516cbf37STim Bird	  Set this option to 'Y' to have the kernel ignore the boot loader
2401516cbf37STim Bird	  command line, and use ONLY the built-in command line.
2402516cbf37STim Bird
2403516cbf37STim Bird	  This is used to work around broken boot loaders.  This should
2404516cbf37STim Bird	  be set to 'N' under normal conditions.
2405516cbf37STim Bird
2406a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL
2407a5b9e5a2SAndy Lutomirski	bool "Enable the LDT (local descriptor table)" if EXPERT
2408a5b9e5a2SAndy Lutomirski	default y
2409a7f7f624SMasahiro Yamada	help
2410a5b9e5a2SAndy Lutomirski	  Linux can allow user programs to install a per-process x86
2411a5b9e5a2SAndy Lutomirski	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2412a5b9e5a2SAndy Lutomirski	  call.  This is required to run 16-bit or segmented code such as
2413a5b9e5a2SAndy Lutomirski	  DOSEMU or some Wine programs.  It is also used by some very old
2414a5b9e5a2SAndy Lutomirski	  threading libraries.
2415a5b9e5a2SAndy Lutomirski
2416a5b9e5a2SAndy Lutomirski	  Enabling this feature adds a small amount of overhead to
2417a5b9e5a2SAndy Lutomirski	  context switches and increases the low-level kernel attack
2418a5b9e5a2SAndy Lutomirski	  surface.  Disabling it removes the modify_ldt(2) system call.
2419a5b9e5a2SAndy Lutomirski
2420a5b9e5a2SAndy Lutomirski	  Saying 'N' here may make sense for embedded or server kernels.
2421a5b9e5a2SAndy Lutomirski
24223aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE
24233aac3ebeSThomas Gleixner	bool "Enforce strict size checking for sigaltstack"
24243aac3ebeSThomas Gleixner	depends on DYNAMIC_SIGFRAME
24253aac3ebeSThomas Gleixner	help
24263aac3ebeSThomas Gleixner	  For historical reasons MINSIGSTKSZ is a constant which became
24273aac3ebeSThomas Gleixner	  already too small with AVX512 support. Add a mechanism to
24283aac3ebeSThomas Gleixner	  enforce strict checking of the sigaltstack size against the
24293aac3ebeSThomas Gleixner	  real size of the FPU frame. This option enables the check
24303aac3ebeSThomas Gleixner	  by default. It can also be controlled via the kernel command
24313aac3ebeSThomas Gleixner	  line option 'strict_sas_size' independent of this config
24323aac3ebeSThomas Gleixner	  switch. Enabling it might break existing applications which
24333aac3ebeSThomas Gleixner	  allocate a too small sigaltstack but 'work' because they
24343aac3ebeSThomas Gleixner	  never get a signal delivered.
24353aac3ebeSThomas Gleixner
24363aac3ebeSThomas Gleixner	  Say 'N' unless you want to really enforce this check.
24373aac3ebeSThomas Gleixner
2438b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig"
2439b700e7f0SSeth Jennings
2440506f1d07SSam Ravnborgendmenu
2441506f1d07SSam Ravnborg
24421ca3683cSUros Bizjakconfig CC_HAS_NAMED_AS
24431ca3683cSUros Bizjak	def_bool CC_IS_GCC && GCC_VERSION >= 120100
24441ca3683cSUros Bizjak
24451ca3683cSUros Bizjakconfig USE_X86_SEG_SUPPORT
24461ca3683cSUros Bizjak	def_bool y
2447e29aad08SUros Bizjak	depends on CC_HAS_NAMED_AS
2448e29aad08SUros Bizjak	#
2449e29aad08SUros Bizjak	# -fsanitize=kernel-address (KASAN) is at the moment incompatible
2450e29aad08SUros Bizjak	# with named address spaces - see GCC PR sanitizer/111736.
2451e29aad08SUros Bizjak	#
2452e29aad08SUros Bizjak	depends on !KASAN
2453b6540de9SUros Bizjak	# -fsanitize=thread (KCSAN) is also incompatible.
2454b6540de9SUros Bizjak	depends on !KCSAN
24551ca3683cSUros Bizjak
2456f43b9876SPeter Zijlstraconfig CC_HAS_SLS
2457f43b9876SPeter Zijlstra	def_bool $(cc-option,-mharden-sls=all)
2458f43b9876SPeter Zijlstra
2459f43b9876SPeter Zijlstraconfig CC_HAS_RETURN_THUNK
2460f43b9876SPeter Zijlstra	def_bool $(cc-option,-mfunction-return=thunk-extern)
2461f43b9876SPeter Zijlstra
2462bea75b33SThomas Gleixnerconfig CC_HAS_ENTRY_PADDING
2463bea75b33SThomas Gleixner	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2464bea75b33SThomas Gleixner
2465bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_CFI
2466bea75b33SThomas Gleixner	int
2467bea75b33SThomas Gleixner	default 59 if FUNCTION_ALIGNMENT_64B
2468bea75b33SThomas Gleixner	default 27 if FUNCTION_ALIGNMENT_32B
2469bea75b33SThomas Gleixner	default 11 if FUNCTION_ALIGNMENT_16B
2470bea75b33SThomas Gleixner	default  3 if FUNCTION_ALIGNMENT_8B
2471bea75b33SThomas Gleixner	default  0
2472bea75b33SThomas Gleixner
2473bea75b33SThomas Gleixner# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2474bea75b33SThomas Gleixner# except Kconfig can't do arithmetic :/
2475bea75b33SThomas Gleixnerconfig FUNCTION_PADDING_BYTES
2476bea75b33SThomas Gleixner	int
2477bea75b33SThomas Gleixner	default FUNCTION_PADDING_CFI if CFI_CLANG
2478bea75b33SThomas Gleixner	default FUNCTION_ALIGNMENT
2479bea75b33SThomas Gleixner
2480931ab636SPeter Zijlstraconfig CALL_PADDING
2481931ab636SPeter Zijlstra	def_bool n
2482931ab636SPeter Zijlstra	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2483931ab636SPeter Zijlstra	select FUNCTION_ALIGNMENT_16B
2484931ab636SPeter Zijlstra
2485931ab636SPeter Zijlstraconfig FINEIBT
2486931ab636SPeter Zijlstra	def_bool y
2487aefb2f2eSBreno Leitao	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
2488931ab636SPeter Zijlstra	select CALL_PADDING
2489931ab636SPeter Zijlstra
24908f7c0d8bSThomas Gleixnerconfig HAVE_CALL_THUNKS
24918f7c0d8bSThomas Gleixner	def_bool y
24920911b8c5SBreno Leitao	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
24938f7c0d8bSThomas Gleixner
24948f7c0d8bSThomas Gleixnerconfig CALL_THUNKS
24958f7c0d8bSThomas Gleixner	def_bool n
2496931ab636SPeter Zijlstra	select CALL_PADDING
24978f7c0d8bSThomas Gleixner
2498b341b20dSPeter Zijlstraconfig PREFIX_SYMBOLS
2499b341b20dSPeter Zijlstra	def_bool y
2500931ab636SPeter Zijlstra	depends on CALL_PADDING && !CFI_CLANG
2501b341b20dSPeter Zijlstra
2502f43b9876SPeter Zijlstramenuconfig SPECULATION_MITIGATIONS
2503f43b9876SPeter Zijlstra	bool "Mitigations for speculative execution vulnerabilities"
2504f43b9876SPeter Zijlstra	default y
2505f43b9876SPeter Zijlstra	help
2506f43b9876SPeter Zijlstra	  Say Y here to enable options which enable mitigations for
2507f43b9876SPeter Zijlstra	  speculative execution hardware vulnerabilities.
2508f43b9876SPeter Zijlstra
2509f43b9876SPeter Zijlstra	  If you say N, all mitigations will be disabled. You really
2510f43b9876SPeter Zijlstra	  should know what you are doing to say so.
2511f43b9876SPeter Zijlstra
2512f43b9876SPeter Zijlstraif SPECULATION_MITIGATIONS
2513f43b9876SPeter Zijlstra
2514ea4654e0SBreno Leitaoconfig MITIGATION_PAGE_TABLE_ISOLATION
2515f43b9876SPeter Zijlstra	bool "Remove the kernel mapping in user mode"
2516f43b9876SPeter Zijlstra	default y
2517f43b9876SPeter Zijlstra	depends on (X86_64 || X86_PAE)
2518f43b9876SPeter Zijlstra	help
2519f43b9876SPeter Zijlstra	  This feature reduces the number of hardware side channels by
2520f43b9876SPeter Zijlstra	  ensuring that the majority of kernel addresses are not mapped
2521f43b9876SPeter Zijlstra	  into userspace.
2522f43b9876SPeter Zijlstra
2523ff61f079SJonathan Corbet	  See Documentation/arch/x86/pti.rst for more details.
2524f43b9876SPeter Zijlstra
2525aefb2f2eSBreno Leitaoconfig MITIGATION_RETPOLINE
2526f43b9876SPeter Zijlstra	bool "Avoid speculative indirect branches in kernel"
2527f43b9876SPeter Zijlstra	select OBJTOOL if HAVE_OBJTOOL
2528f43b9876SPeter Zijlstra	default y
2529f43b9876SPeter Zijlstra	help
2530f43b9876SPeter Zijlstra	  Compile kernel with the retpoline compiler options to guard against
2531f43b9876SPeter Zijlstra	  kernel-to-user data leaks by avoiding speculative indirect
2532f43b9876SPeter Zijlstra	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2533f43b9876SPeter Zijlstra	  support for full protection. The kernel may run slower.
2534f43b9876SPeter Zijlstra
25350911b8c5SBreno Leitaoconfig MITIGATION_RETHUNK
2536f43b9876SPeter Zijlstra	bool "Enable return-thunks"
2537aefb2f2eSBreno Leitao	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2538f43b9876SPeter Zijlstra	select OBJTOOL if HAVE_OBJTOOL
2539b648ab48SBen Hutchings	default y if X86_64
2540f43b9876SPeter Zijlstra	help
2541f43b9876SPeter Zijlstra	  Compile the kernel with the return-thunks compiler option to guard
2542f43b9876SPeter Zijlstra	  against kernel-to-user data leaks by avoiding return speculation.
2543f43b9876SPeter Zijlstra	  Requires a compiler with -mfunction-return=thunk-extern
2544f43b9876SPeter Zijlstra	  support for full protection. The kernel may run slower.
2545f43b9876SPeter Zijlstra
2546ac61d439SBreno Leitaoconfig MITIGATION_UNRET_ENTRY
2547f43b9876SPeter Zijlstra	bool "Enable UNRET on kernel entry"
25480911b8c5SBreno Leitao	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2549f43b9876SPeter Zijlstra	default y
2550f43b9876SPeter Zijlstra	help
2551f43b9876SPeter Zijlstra	  Compile the kernel with support for the retbleed=unret mitigation.
2552f43b9876SPeter Zijlstra
25535fa31af3SBreno Leitaoconfig MITIGATION_CALL_DEPTH_TRACKING
255480e4c1cdSThomas Gleixner	bool "Mitigate RSB underflow with call depth tracking"
255580e4c1cdSThomas Gleixner	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
255680e4c1cdSThomas Gleixner	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
255780e4c1cdSThomas Gleixner	select CALL_THUNKS
255880e4c1cdSThomas Gleixner	default y
255980e4c1cdSThomas Gleixner	help
256080e4c1cdSThomas Gleixner	  Compile the kernel with call depth tracking to mitigate the Intel
256180e4c1cdSThomas Gleixner	  SKL Return-Speculation-Buffer (RSB) underflow issue. The
256280e4c1cdSThomas Gleixner	  mitigation is off by default and needs to be enabled on the
256380e4c1cdSThomas Gleixner	  kernel command line via the retbleed=stuff option. For
256480e4c1cdSThomas Gleixner	  non-affected systems the overhead of this option is marginal as
256580e4c1cdSThomas Gleixner	  the call depth tracking is using run-time generated call thunks
256680e4c1cdSThomas Gleixner	  in a compiler generated padding area and call patching. This
256780e4c1cdSThomas Gleixner	  increases text size by ~5%. For non affected systems this space
256880e4c1cdSThomas Gleixner	  is unused. On affected SKL systems this results in a significant
256980e4c1cdSThomas Gleixner	  performance gain over the IBRS mitigation.
257080e4c1cdSThomas Gleixner
2571e81dc127SThomas Gleixnerconfig CALL_THUNKS_DEBUG
2572e81dc127SThomas Gleixner	bool "Enable call thunks and call depth tracking debugging"
25735fa31af3SBreno Leitao	depends on MITIGATION_CALL_DEPTH_TRACKING
2574e81dc127SThomas Gleixner	select FUNCTION_ALIGNMENT_32B
2575e81dc127SThomas Gleixner	default n
2576e81dc127SThomas Gleixner	help
2577e81dc127SThomas Gleixner	  Enable call/ret counters for imbalance detection and build in
2578e81dc127SThomas Gleixner	  a noisy dmesg about callthunks generation and call patching for
2579e81dc127SThomas Gleixner	  trouble shooting. The debug prints need to be enabled on the
2580e81dc127SThomas Gleixner	  kernel command line with 'debug-callthunks'.
258154628de6SRandy Dunlap	  Only enable this when you are debugging call thunks as this
258254628de6SRandy Dunlap	  creates a noticeable runtime overhead. If unsure say N.
258380e4c1cdSThomas Gleixner
2584e0b8fcfaSBreno Leitaoconfig MITIGATION_IBPB_ENTRY
2585f43b9876SPeter Zijlstra	bool "Enable IBPB on kernel entry"
2586b648ab48SBen Hutchings	depends on CPU_SUP_AMD && X86_64
2587f43b9876SPeter Zijlstra	default y
2588f43b9876SPeter Zijlstra	help
2589f43b9876SPeter Zijlstra	  Compile the kernel with support for the retbleed=ibpb mitigation.
2590f43b9876SPeter Zijlstra
25911da8d217SBreno Leitaoconfig MITIGATION_IBRS_ENTRY
2592f43b9876SPeter Zijlstra	bool "Enable IBRS on kernel entry"
2593b648ab48SBen Hutchings	depends on CPU_SUP_INTEL && X86_64
2594f43b9876SPeter Zijlstra	default y
2595f43b9876SPeter Zijlstra	help
2596f43b9876SPeter Zijlstra	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2597f43b9876SPeter Zijlstra	  This mitigates both spectre_v2 and retbleed at great cost to
2598f43b9876SPeter Zijlstra	  performance.
2599f43b9876SPeter Zijlstra
2600a033eec9SBreno Leitaoconfig MITIGATION_SRSO
2601fb3bd914SBorislav Petkov (AMD)	bool "Mitigate speculative RAS overflow on AMD"
26020911b8c5SBreno Leitao	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2603fb3bd914SBorislav Petkov (AMD)	default y
2604fb3bd914SBorislav Petkov (AMD)	help
2605fb3bd914SBorislav Petkov (AMD)	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2606fb3bd914SBorislav Petkov (AMD)
26077b75782fSBreno Leitaoconfig MITIGATION_SLS
2608f43b9876SPeter Zijlstra	bool "Mitigate Straight-Line-Speculation"
2609f43b9876SPeter Zijlstra	depends on CC_HAS_SLS && X86_64
2610f43b9876SPeter Zijlstra	select OBJTOOL if HAVE_OBJTOOL
2611f43b9876SPeter Zijlstra	default n
2612f43b9876SPeter Zijlstra	help
2613f43b9876SPeter Zijlstra	  Compile the kernel with straight-line-speculation options to guard
2614f43b9876SPeter Zijlstra	  against straight line speculation. The kernel image might be slightly
2615f43b9876SPeter Zijlstra	  larger.
2616f43b9876SPeter Zijlstra
2617be83e809SBreno Leitaoconfig MITIGATION_GDS_FORCE
261853cf5797SDaniel Sneddon	bool "Force GDS Mitigation"
261953cf5797SDaniel Sneddon	depends on CPU_SUP_INTEL
262053cf5797SDaniel Sneddon	default n
262153cf5797SDaniel Sneddon	help
262253cf5797SDaniel Sneddon	  Gather Data Sampling (GDS) is a hardware vulnerability which allows
262353cf5797SDaniel Sneddon	  unprivileged speculative access to data which was previously stored in
262453cf5797SDaniel Sneddon	  vector registers.
262553cf5797SDaniel Sneddon
262653cf5797SDaniel Sneddon	  This option is equivalent to setting gather_data_sampling=force on the
262753cf5797SDaniel Sneddon	  command line. The microcode mitigation is used if present, otherwise
262853cf5797SDaniel Sneddon	  AVX is disabled as a mitigation. On affected systems that are missing
262953cf5797SDaniel Sneddon	  the microcode any userspace code that unconditionally uses AVX will
263053cf5797SDaniel Sneddon	  break with this option set.
263153cf5797SDaniel Sneddon
263253cf5797SDaniel Sneddon	  Setting this option on systems not vulnerable to GDS has no effect.
263353cf5797SDaniel Sneddon
263453cf5797SDaniel Sneddon	  If in doubt, say N.
263553cf5797SDaniel Sneddon
26368076fcdeSPawan Guptaconfig MITIGATION_RFDS
26378076fcdeSPawan Gupta	bool "RFDS Mitigation"
26388076fcdeSPawan Gupta	depends on CPU_SUP_INTEL
26398076fcdeSPawan Gupta	default y
26408076fcdeSPawan Gupta	help
26418076fcdeSPawan Gupta	  Enable mitigation for Register File Data Sampling (RFDS) by default.
26428076fcdeSPawan Gupta	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
26438076fcdeSPawan Gupta	  allows unprivileged speculative access to stale data previously
26448076fcdeSPawan Gupta	  stored in floating point, vector and integer registers.
26458076fcdeSPawan Gupta	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
26468076fcdeSPawan Gupta
26474f511739SJosh Poimboeufconfig MITIGATION_SPECTRE_BHI
26484f511739SJosh Poimboeuf	bool "Mitigate Spectre-BHB (Branch History Injection)"
2649ec9404e4SPawan Gupta	depends on CPU_SUP_INTEL
26504f511739SJosh Poimboeuf	default y
2651ec9404e4SPawan Gupta	help
2652ec9404e4SPawan Gupta	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2653ec9404e4SPawan Gupta	  where the branch history buffer is poisoned to speculatively steer
2654ec9404e4SPawan Gupta	  indirect branches.
2655ec9404e4SPawan Gupta	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2656ec9404e4SPawan Gupta
2657f43b9876SPeter Zijlstraendif
2658f43b9876SPeter Zijlstra
26593072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES
26603072e413SMichal Hocko	def_bool y
26615c11f00bSDavid Hildenbrand	depends on ARCH_ENABLE_MEMORY_HOTPLUG
26623072e413SMichal Hocko
2663da85f865SBjorn Helgaasmenu "Power management and ACPI options"
2664e279b6c1SSam Ravnborg
2665e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER
26663c2362e6SHarvey Harrison	def_bool y
266744556530SZhimin Gu	depends on HIBERNATION
2668e279b6c1SSam Ravnborg
2669e279b6c1SSam Ravnborgsource "kernel/power/Kconfig"
2670e279b6c1SSam Ravnborg
2671e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig"
2672e279b6c1SSam Ravnborg
2673a6b68076SAndi Kleenconfig X86_APM_BOOT
26746fc108a0SJan Beulich	def_bool y
2675282e5aabSPaul Bolle	depends on APM
2676a6b68076SAndi Kleen
2677e279b6c1SSam Ravnborgmenuconfig APM
2678e279b6c1SSam Ravnborg	tristate "APM (Advanced Power Management) BIOS support"
2679efefa6f6SIngo Molnar	depends on X86_32 && PM_SLEEP
2680a7f7f624SMasahiro Yamada	help
2681e279b6c1SSam Ravnborg	  APM is a BIOS specification for saving power using several different
2682e279b6c1SSam Ravnborg	  techniques. This is mostly useful for battery powered laptops with
2683e279b6c1SSam Ravnborg	  APM compliant BIOSes. If you say Y here, the system time will be
2684e279b6c1SSam Ravnborg	  reset after a RESUME operation, the /proc/apm device will provide
2685e279b6c1SSam Ravnborg	  battery status information, and user-space programs will receive
2686e279b6c1SSam Ravnborg	  notification of APM "events" (e.g. battery status change).
2687e279b6c1SSam Ravnborg
2688e279b6c1SSam Ravnborg	  If you select "Y" here, you can disable actual use of the APM
2689e279b6c1SSam Ravnborg	  BIOS by passing the "apm=off" option to the kernel at boot time.
2690e279b6c1SSam Ravnborg
2691e279b6c1SSam Ravnborg	  Note that the APM support is almost completely disabled for
2692e279b6c1SSam Ravnborg	  machines with more than one CPU.
2693e279b6c1SSam Ravnborg
2694e279b6c1SSam Ravnborg	  In order to use APM, you will need supporting software. For location
2695151f4e2bSMauro Carvalho Chehab	  and more information, read <file:Documentation/power/apm-acpi.rst>
26962dc98fd3SMichael Witten	  and the Battery Powered Linux mini-HOWTO, available from
2697e279b6c1SSam Ravnborg	  <http://www.tldp.org/docs.html#howto>.
2698e279b6c1SSam Ravnborg
2699e279b6c1SSam Ravnborg	  This driver does not spin down disk drives (see the hdparm(8)
2700e279b6c1SSam Ravnborg	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2701e279b6c1SSam Ravnborg	  VESA-compliant "green" monitors.
2702e279b6c1SSam Ravnborg
2703e279b6c1SSam Ravnborg	  This driver does not support the TI 4000M TravelMate and the ACER
2704e279b6c1SSam Ravnborg	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2705e279b6c1SSam Ravnborg	  desktop machines also don't have compliant BIOSes, and this driver
2706e279b6c1SSam Ravnborg	  may cause those machines to panic during the boot phase.
2707e279b6c1SSam Ravnborg
2708e279b6c1SSam Ravnborg	  Generally, if you don't have a battery in your machine, there isn't
2709e279b6c1SSam Ravnborg	  much point in using this driver and you should say N. If you get
2710e279b6c1SSam Ravnborg	  random kernel OOPSes or reboots that don't seem to be related to
2711e279b6c1SSam Ravnborg	  anything, try disabling/enabling this option (or disabling/enabling
2712e279b6c1SSam Ravnborg	  APM in your BIOS).
2713e279b6c1SSam Ravnborg
2714e279b6c1SSam Ravnborg	  Some other things you should try when experiencing seemingly random,
2715e279b6c1SSam Ravnborg	  "weird" problems:
2716e279b6c1SSam Ravnborg
2717e279b6c1SSam Ravnborg	  1) make sure that you have enough swap space and that it is
2718e279b6c1SSam Ravnborg	  enabled.
27197987448fSStephen Kitt	  2) pass the "idle=poll" option to the kernel
2720e279b6c1SSam Ravnborg	  3) switch on floating point emulation in the kernel and pass
2721e279b6c1SSam Ravnborg	  the "no387" option to the kernel
2722e279b6c1SSam Ravnborg	  4) pass the "floppy=nodma" option to the kernel
2723e279b6c1SSam Ravnborg	  5) pass the "mem=4M" option to the kernel (thereby disabling
2724e279b6c1SSam Ravnborg	  all but the first 4 MB of RAM)
2725e279b6c1SSam Ravnborg	  6) make sure that the CPU is not over clocked.
2726e279b6c1SSam Ravnborg	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2727e279b6c1SSam Ravnborg	  8) disable the cache from your BIOS settings
2728e279b6c1SSam Ravnborg	  9) install a fan for the video card or exchange video RAM
2729e279b6c1SSam Ravnborg	  10) install a better fan for the CPU
2730e279b6c1SSam Ravnborg	  11) exchange RAM chips
2731e279b6c1SSam Ravnborg	  12) exchange the motherboard.
2732e279b6c1SSam Ravnborg
2733e279b6c1SSam Ravnborg	  To compile this driver as a module, choose M here: the
2734e279b6c1SSam Ravnborg	  module will be called apm.
2735e279b6c1SSam Ravnborg
2736e279b6c1SSam Ravnborgif APM
2737e279b6c1SSam Ravnborg
2738e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND
2739e279b6c1SSam Ravnborg	bool "Ignore USER SUSPEND"
2740a7f7f624SMasahiro Yamada	help
2741e279b6c1SSam Ravnborg	  This option will ignore USER SUSPEND requests. On machines with a
2742e279b6c1SSam Ravnborg	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2743e279b6c1SSam Ravnborg	  series notebooks, it is necessary to say Y because of a BIOS bug.
2744e279b6c1SSam Ravnborg
2745e279b6c1SSam Ravnborgconfig APM_DO_ENABLE
2746e279b6c1SSam Ravnborg	bool "Enable PM at boot time"
2747a7f7f624SMasahiro Yamada	help
2748e279b6c1SSam Ravnborg	  Enable APM features at boot time. From page 36 of the APM BIOS
2749e279b6c1SSam Ravnborg	  specification: "When disabled, the APM BIOS does not automatically
2750e279b6c1SSam Ravnborg	  power manage devices, enter the Standby State, enter the Suspend
2751e279b6c1SSam Ravnborg	  State, or take power saving steps in response to CPU Idle calls."
2752e279b6c1SSam Ravnborg	  This driver will make CPU Idle calls when Linux is idle (unless this
2753e279b6c1SSam Ravnborg	  feature is turned off -- see "Do CPU IDLE calls", below). This
2754e279b6c1SSam Ravnborg	  should always save battery power, but more complicated APM features
2755e279b6c1SSam Ravnborg	  will be dependent on your BIOS implementation. You may need to turn
2756e279b6c1SSam Ravnborg	  this option off if your computer hangs at boot time when using APM
2757e279b6c1SSam Ravnborg	  support, or if it beeps continuously instead of suspending. Turn
2758e279b6c1SSam Ravnborg	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2759e279b6c1SSam Ravnborg	  T400CDT. This is off by default since most machines do fine without
2760e279b6c1SSam Ravnborg	  this feature.
2761e279b6c1SSam Ravnborg
2762e279b6c1SSam Ravnborgconfig APM_CPU_IDLE
2763dd8af076SLen Brown	depends on CPU_IDLE
2764e279b6c1SSam Ravnborg	bool "Make CPU Idle calls when idle"
2765a7f7f624SMasahiro Yamada	help
2766e279b6c1SSam Ravnborg	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2767e279b6c1SSam Ravnborg	  On some machines, this can activate improved power savings, such as
2768e279b6c1SSam Ravnborg	  a slowed CPU clock rate, when the machine is idle. These idle calls
2769e279b6c1SSam Ravnborg	  are made after the idle loop has run for some length of time (e.g.,
2770e279b6c1SSam Ravnborg	  333 mS). On some machines, this will cause a hang at boot time or
2771e279b6c1SSam Ravnborg	  whenever the CPU becomes idle. (On machines with more than one CPU,
2772e279b6c1SSam Ravnborg	  this option does nothing.)
2773e279b6c1SSam Ravnborg
2774e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK
2775e279b6c1SSam Ravnborg	bool "Enable console blanking using APM"
2776a7f7f624SMasahiro Yamada	help
2777e279b6c1SSam Ravnborg	  Enable console blanking using the APM. Some laptops can use this to
2778e279b6c1SSam Ravnborg	  turn off the LCD backlight when the screen blanker of the Linux
2779e279b6c1SSam Ravnborg	  virtual console blanks the screen. Note that this is only used by
2780e279b6c1SSam Ravnborg	  the virtual console screen blanker, and won't turn off the backlight
2781e279b6c1SSam Ravnborg	  when using the X Window system. This also doesn't have anything to
2782e279b6c1SSam Ravnborg	  do with your VESA-compliant power-saving monitor. Further, this
2783e279b6c1SSam Ravnborg	  option doesn't work for all laptops -- it might not turn off your
2784e279b6c1SSam Ravnborg	  backlight at all, or it might print a lot of errors to the console,
2785e279b6c1SSam Ravnborg	  especially if you are using gpm.
2786e279b6c1SSam Ravnborg
2787e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS
2788e279b6c1SSam Ravnborg	bool "Allow interrupts during APM BIOS calls"
2789a7f7f624SMasahiro Yamada	help
2790e279b6c1SSam Ravnborg	  Normally we disable external interrupts while we are making calls to
2791e279b6c1SSam Ravnborg	  the APM BIOS as a measure to lessen the effects of a badly behaving
2792e279b6c1SSam Ravnborg	  BIOS implementation.  The BIOS should reenable interrupts if it
2793e279b6c1SSam Ravnborg	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2794e279b6c1SSam Ravnborg	  many of the newer IBM Thinkpads.  If you experience hangs when you
2795e279b6c1SSam Ravnborg	  suspend, try setting this to Y.  Otherwise, say N.
2796e279b6c1SSam Ravnborg
2797e279b6c1SSam Ravnborgendif # APM
2798e279b6c1SSam Ravnborg
2799bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig"
2800e279b6c1SSam Ravnborg
2801e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig"
2802e279b6c1SSam Ravnborg
280327471fdbSAndy Henroidsource "drivers/idle/Kconfig"
280427471fdbSAndy Henroid
2805e279b6c1SSam Ravnborgendmenu
2806e279b6c1SSam Ravnborg
2807e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)"
2808e279b6c1SSam Ravnborg
2809e279b6c1SSam Ravnborgchoice
2810e279b6c1SSam Ravnborg	prompt "PCI access mode"
2811efefa6f6SIngo Molnar	depends on X86_32 && PCI
2812e279b6c1SSam Ravnborg	default PCI_GOANY
2813a7f7f624SMasahiro Yamada	help
2814e279b6c1SSam Ravnborg	  On PCI systems, the BIOS can be used to detect the PCI devices and
2815e279b6c1SSam Ravnborg	  determine their configuration. However, some old PCI motherboards
2816e279b6c1SSam Ravnborg	  have BIOS bugs and may crash if this is done. Also, some embedded
2817e279b6c1SSam Ravnborg	  PCI-based systems don't have any BIOS at all. Linux can also try to
2818e279b6c1SSam Ravnborg	  detect the PCI hardware directly without using the BIOS.
2819e279b6c1SSam Ravnborg
2820e279b6c1SSam Ravnborg	  With this option, you can specify how Linux should detect the
2821e279b6c1SSam Ravnborg	  PCI devices. If you choose "BIOS", the BIOS will be used,
2822e279b6c1SSam Ravnborg	  if you choose "Direct", the BIOS won't be used, and if you
2823e279b6c1SSam Ravnborg	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2824e279b6c1SSam Ravnborg	  If you choose "Any", the kernel will try MMCONFIG, then the
2825e279b6c1SSam Ravnborg	  direct access method and falls back to the BIOS if that doesn't
2826e279b6c1SSam Ravnborg	  work. If unsure, go with the default, which is "Any".
2827e279b6c1SSam Ravnborg
2828e279b6c1SSam Ravnborgconfig PCI_GOBIOS
2829e279b6c1SSam Ravnborg	bool "BIOS"
2830e279b6c1SSam Ravnborg
2831e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG
2832e279b6c1SSam Ravnborg	bool "MMConfig"
2833e279b6c1SSam Ravnborg
2834e279b6c1SSam Ravnborgconfig PCI_GODIRECT
2835e279b6c1SSam Ravnborg	bool "Direct"
2836e279b6c1SSam Ravnborg
28373ef0e1f8SAndres Salomonconfig PCI_GOOLPC
283876fb6570SDaniel Drake	bool "OLPC XO-1"
28393ef0e1f8SAndres Salomon	depends on OLPC
28403ef0e1f8SAndres Salomon
28412bdd1b03SAndres Salomonconfig PCI_GOANY
28422bdd1b03SAndres Salomon	bool "Any"
28432bdd1b03SAndres Salomon
2844e279b6c1SSam Ravnborgendchoice
2845e279b6c1SSam Ravnborg
2846e279b6c1SSam Ravnborgconfig PCI_BIOS
28473c2362e6SHarvey Harrison	def_bool y
2848efefa6f6SIngo Molnar	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2849e279b6c1SSam Ravnborg
2850e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2851e279b6c1SSam Ravnborgconfig PCI_DIRECT
28523c2362e6SHarvey Harrison	def_bool y
28530aba496fSShaohua Li	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2854e279b6c1SSam Ravnborg
2855e279b6c1SSam Ravnborgconfig PCI_MMCONFIG
2856b45c9f36SJan Kiszka	bool "Support mmconfig PCI config space access" if X86_64
2857b45c9f36SJan Kiszka	default y
28584590d98fSAndy Shevchenko	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2859b45c9f36SJan Kiszka	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2860e279b6c1SSam Ravnborg
28613ef0e1f8SAndres Salomonconfig PCI_OLPC
28622bdd1b03SAndres Salomon	def_bool y
28632bdd1b03SAndres Salomon	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
28643ef0e1f8SAndres Salomon
2865b5401a96SAlex Nixonconfig PCI_XEN
2866b5401a96SAlex Nixon	def_bool y
2867b5401a96SAlex Nixon	depends on PCI && XEN
2868b5401a96SAlex Nixon
28698364e1f8SJan Kiszkaconfig MMCONF_FAM10H
28708364e1f8SJan Kiszka	def_bool y
28718364e1f8SJan Kiszka	depends on X86_64 && PCI_MMCONFIG && ACPI
2872e279b6c1SSam Ravnborg
28733f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK
28746a108a14SDavid Rientjes	bool "Read CNB20LE Host Bridge Windows" if EXPERT
28756ea30386SKees Cook	depends on PCI
28763f6ea84aSIra W. Snyder	help
28773f6ea84aSIra W. Snyder	  Read the PCI windows out of the CNB20LE host bridge. This allows
28783f6ea84aSIra W. Snyder	  PCI hotplug to work on systems with the CNB20LE chipset which do
28793f6ea84aSIra W. Snyder	  not have ACPI.
28803f6ea84aSIra W. Snyder
288164a5fed6SBjorn Helgaas	  There's no public spec for this chipset, and this functionality
288264a5fed6SBjorn Helgaas	  is known to be incomplete.
288364a5fed6SBjorn Helgaas
288464a5fed6SBjorn Helgaas	  You should say N unless you know you need this.
288564a5fed6SBjorn Helgaas
28863a495511SWilliam Breathitt Grayconfig ISA_BUS
288717a2a129SWilliam Breathitt Gray	bool "ISA bus support on modern systems" if EXPERT
28883a495511SWilliam Breathitt Gray	help
288917a2a129SWilliam Breathitt Gray	  Expose ISA bus device drivers and options available for selection and
289017a2a129SWilliam Breathitt Gray	  configuration. Enable this option if your target machine has an ISA
289117a2a129SWilliam Breathitt Gray	  bus. ISA is an older system, displaced by PCI and newer bus
289217a2a129SWilliam Breathitt Gray	  architectures -- if your target machine is modern, it probably does
289317a2a129SWilliam Breathitt Gray	  not have an ISA bus.
28943a495511SWilliam Breathitt Gray
28953a495511SWilliam Breathitt Gray	  If unsure, say N.
28963a495511SWilliam Breathitt Gray
28971c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA.
2898e279b6c1SSam Ravnborgconfig ISA_DMA_API
28991c00f016SDavid Rientjes	bool "ISA-style DMA support" if (X86_64 && EXPERT)
29001c00f016SDavid Rientjes	default y
29011c00f016SDavid Rientjes	help
29021c00f016SDavid Rientjes	  Enables ISA-style DMA support for devices requiring such controllers.
29031c00f016SDavid Rientjes	  If unsure, say Y.
2904e279b6c1SSam Ravnborg
290551e68d05SLinus Torvaldsif X86_32
290651e68d05SLinus Torvalds
2907e279b6c1SSam Ravnborgconfig ISA
2908e279b6c1SSam Ravnborg	bool "ISA support"
2909a7f7f624SMasahiro Yamada	help
2910e279b6c1SSam Ravnborg	  Find out whether you have ISA slots on your motherboard.  ISA is the
2911e279b6c1SSam Ravnborg	  name of a bus system, i.e. the way the CPU talks to the other stuff
2912e279b6c1SSam Ravnborg	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2913e279b6c1SSam Ravnborg	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2914e279b6c1SSam Ravnborg	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2915e279b6c1SSam Ravnborg
2916e279b6c1SSam Ravnborgconfig SCx200
2917e279b6c1SSam Ravnborg	tristate "NatSemi SCx200 support"
2918a7f7f624SMasahiro Yamada	help
2919e279b6c1SSam Ravnborg	  This provides basic support for National Semiconductor's
2920e279b6c1SSam Ravnborg	  (now AMD's) Geode processors.  The driver probes for the
2921e279b6c1SSam Ravnborg	  PCI-IDs of several on-chip devices, so its a good dependency
2922e279b6c1SSam Ravnborg	  for other scx200_* drivers.
2923e279b6c1SSam Ravnborg
2924e279b6c1SSam Ravnborg	  If compiled as a module, the driver is named scx200.
2925e279b6c1SSam Ravnborg
2926e279b6c1SSam Ravnborgconfig SCx200HR_TIMER
2927e279b6c1SSam Ravnborg	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2928592913ecSJohn Stultz	depends on SCx200
2929e279b6c1SSam Ravnborg	default y
2930a7f7f624SMasahiro Yamada	help
2931e279b6c1SSam Ravnborg	  This driver provides a clocksource built upon the on-chip
2932e279b6c1SSam Ravnborg	  27MHz high-resolution timer.  Its also a workaround for
2933e279b6c1SSam Ravnborg	  NSC Geode SC-1100's buggy TSC, which loses time when the
2934e279b6c1SSam Ravnborg	  processor goes idle (as is done by the scheduler).  The
2935e279b6c1SSam Ravnborg	  other workaround is idle=poll boot option.
2936e279b6c1SSam Ravnborg
29373ef0e1f8SAndres Salomonconfig OLPC
29383ef0e1f8SAndres Salomon	bool "One Laptop Per Child support"
293954008979SThomas Gleixner	depends on !X86_PAE
29403c554946SAndres Salomon	select GPIOLIB
2941dc3119e7SThomas Gleixner	select OF
294245bb1674SDaniel Drake	select OF_PROMTREE
2943b4e51854SGrant Likely	select IRQ_DOMAIN
29440c3d931bSLubomir Rintel	select OLPC_EC
2945a7f7f624SMasahiro Yamada	help
29463ef0e1f8SAndres Salomon	  Add support for detecting the unique features of the OLPC
29473ef0e1f8SAndres Salomon	  XO hardware.
29483ef0e1f8SAndres Salomon
2949a3128588SDaniel Drakeconfig OLPC_XO1_PM
2950a3128588SDaniel Drake	bool "OLPC XO-1 Power Management"
2951fa112cf1SBorislav Petkov	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2952a7f7f624SMasahiro Yamada	help
295397c4cb71SDaniel Drake	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2954bf1ebf00SDaniel Drake
2955cfee9597SDaniel Drakeconfig OLPC_XO1_RTC
2956cfee9597SDaniel Drake	bool "OLPC XO-1 Real Time Clock"
2957cfee9597SDaniel Drake	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2958a7f7f624SMasahiro Yamada	help
2959cfee9597SDaniel Drake	  Add support for the XO-1 real time clock, which can be used as a
2960cfee9597SDaniel Drake	  programmable wakeup source.
2961cfee9597SDaniel Drake
29627feda8e9SDaniel Drakeconfig OLPC_XO1_SCI
29637feda8e9SDaniel Drake	bool "OLPC XO-1 SCI extras"
296492e830f2SArnd Bergmann	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2965ed8e47feSRandy Dunlap	depends on INPUT=y
2966d8d01a63SDaniel Drake	select POWER_SUPPLY
2967a7f7f624SMasahiro Yamada	help
29687feda8e9SDaniel Drake	  Add support for SCI-based features of the OLPC XO-1 laptop:
29697bc74b3dSDaniel Drake	   - EC-driven system wakeups
29707feda8e9SDaniel Drake	   - Power button
29717bc74b3dSDaniel Drake	   - Ebook switch
29722cf2baeaSDaniel Drake	   - Lid switch
2973e1040ac6SDaniel Drake	   - AC adapter status updates
2974e1040ac6SDaniel Drake	   - Battery status updates
29757feda8e9SDaniel Drake
2976a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI
2977a0f30f59SDaniel Drake	bool "OLPC XO-1.5 SCI extras"
2978d8d01a63SDaniel Drake	depends on OLPC && ACPI
2979d8d01a63SDaniel Drake	select POWER_SUPPLY
2980a7f7f624SMasahiro Yamada	help
2981a0f30f59SDaniel Drake	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2982a0f30f59SDaniel Drake	   - EC-driven system wakeups
2983a0f30f59SDaniel Drake	   - AC adapter status updates
2984a0f30f59SDaniel Drake	   - Battery status updates
2985e279b6c1SSam Ravnborg
2986d4f3e350SEd Wildgooseconfig ALIX
2987d4f3e350SEd Wildgoose	bool "PCEngines ALIX System Support (LED setup)"
2988d4f3e350SEd Wildgoose	select GPIOLIB
2989a7f7f624SMasahiro Yamada	help
2990d4f3e350SEd Wildgoose	  This option enables system support for the PCEngines ALIX.
2991d4f3e350SEd Wildgoose	  At present this just sets up LEDs for GPIO control on
2992d4f3e350SEd Wildgoose	  ALIX2/3/6 boards.  However, other system specific setup should
2993d4f3e350SEd Wildgoose	  get added here.
2994d4f3e350SEd Wildgoose
2995d4f3e350SEd Wildgoose	  Note: You must still enable the drivers for GPIO and LED support
2996d4f3e350SEd Wildgoose	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2997d4f3e350SEd Wildgoose
2998d4f3e350SEd Wildgoose	  Note: You have to set alix.force=1 for boards with Award BIOS.
2999d4f3e350SEd Wildgoose
3000da4e3302SPhilip Prindevilleconfig NET5501
3001da4e3302SPhilip Prindeville	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3002da4e3302SPhilip Prindeville	select GPIOLIB
3003a7f7f624SMasahiro Yamada	help
3004da4e3302SPhilip Prindeville	  This option enables system support for the Soekris Engineering net5501.
3005da4e3302SPhilip Prindeville
30063197059aSPhilip A. Prindevilleconfig GEOS
30073197059aSPhilip A. Prindeville	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
30083197059aSPhilip A. Prindeville	select GPIOLIB
30093197059aSPhilip A. Prindeville	depends on DMI
3010a7f7f624SMasahiro Yamada	help
30113197059aSPhilip A. Prindeville	  This option enables system support for the Traverse Technologies GEOS.
30123197059aSPhilip A. Prindeville
30137d029125SVivien Didelotconfig TS5500
30147d029125SVivien Didelot	bool "Technologic Systems TS-5500 platform support"
30157d029125SVivien Didelot	depends on MELAN
30167d029125SVivien Didelot	select CHECK_SIGNATURE
30177d029125SVivien Didelot	select NEW_LEDS
30187d029125SVivien Didelot	select LEDS_CLASS
3019a7f7f624SMasahiro Yamada	help
30207d029125SVivien Didelot	  This option enables system support for the Technologic Systems TS-5500.
30217d029125SVivien Didelot
3022e279b6c1SSam Ravnborgendif # X86_32
3023e279b6c1SSam Ravnborg
302423ac4ae8SAndreas Herrmannconfig AMD_NB
3025e279b6c1SSam Ravnborg	def_bool y
30260e152cd7SBorislav Petkov	depends on CPU_SUP_AMD && PCI
3027e279b6c1SSam Ravnborg
3028e279b6c1SSam Ravnborgendmenu
3029e279b6c1SSam Ravnborg
30301572497cSChristoph Hellwigmenu "Binary Emulations"
3031e279b6c1SSam Ravnborg
3032e279b6c1SSam Ravnborgconfig IA32_EMULATION
3033e279b6c1SSam Ravnborg	bool "IA32 Emulation"
3034e279b6c1SSam Ravnborg	depends on X86_64
303539f88911SIngo Molnar	select ARCH_WANT_OLD_COMPAT_IPC
3036d1603990SRandy Dunlap	select BINFMT_ELF
303739f88911SIngo Molnar	select COMPAT_OLD_SIGACTION
3038a7f7f624SMasahiro Yamada	help
30395fd92e65SH. J. Lu	  Include code to run legacy 32-bit programs under a
30405fd92e65SH. J. Lu	  64-bit kernel. You should likely turn this on, unless you're
30415fd92e65SH. J. Lu	  100% sure that you don't have any 32-bit programs left.
3042e279b6c1SSam Ravnborg
3043a11e0975SNikolay Borisovconfig IA32_EMULATION_DEFAULT_DISABLED
3044a11e0975SNikolay Borisov	bool "IA32 emulation disabled by default"
3045a11e0975SNikolay Borisov	default n
3046a11e0975SNikolay Borisov	depends on IA32_EMULATION
3047a11e0975SNikolay Borisov	help
3048a11e0975SNikolay Borisov	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3049a11e0975SNikolay Borisov	  processes and access to 32-bit syscalls. If unsure, leave it to its
3050a11e0975SNikolay Borisov	  default value.
3051a11e0975SNikolay Borisov
305283a44a4fSMasahiro Yamadaconfig X86_X32_ABI
30536ea30386SKees Cook	bool "x32 ABI for 64-bit mode"
30549b54050bSBrian Gerst	depends on X86_64
3055aaeed6ecSNathan Chancellor	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3056aaeed6ecSNathan Chancellor	# compressed debug sections to x86_x32 properly:
3057aaeed6ecSNathan Chancellor	# https://github.com/ClangBuiltLinux/linux/issues/514
3058aaeed6ecSNathan Chancellor	# https://github.com/ClangBuiltLinux/linux/issues/1141
3059aaeed6ecSNathan Chancellor	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3060a7f7f624SMasahiro Yamada	help
30615fd92e65SH. J. Lu	  Include code to run binaries for the x32 native 32-bit ABI
30625fd92e65SH. J. Lu	  for 64-bit processors.  An x32 process gets access to the
30635fd92e65SH. J. Lu	  full 64-bit register file and wide data path while leaving
30645fd92e65SH. J. Lu	  pointers at 32 bits for smaller memory footprint.
30655fd92e65SH. J. Lu
3066953fee1dSIngo Molnarconfig COMPAT_32
3067953fee1dSIngo Molnar	def_bool y
3068953fee1dSIngo Molnar	depends on IA32_EMULATION || X86_32
3069953fee1dSIngo Molnar	select HAVE_UID16
3070953fee1dSIngo Molnar	select OLD_SIGSUSPEND3
3071953fee1dSIngo Molnar
3072e279b6c1SSam Ravnborgconfig COMPAT
30733c2362e6SHarvey Harrison	def_bool y
307483a44a4fSMasahiro Yamada	depends on IA32_EMULATION || X86_X32_ABI
3075e279b6c1SSam Ravnborg
3076e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT
30773120e25eSJan Beulich	def_bool y
3078a9251280SLinus Torvalds	depends on COMPAT
3079ee009e4aSDavid Howells
3080e279b6c1SSam Ravnborgendmenu
3081e279b6c1SSam Ravnborg
3082e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP
3083e5beae16SKeith Packard	def_bool y
3084e5beae16SKeith Packard	depends on X86_32
3085e5beae16SKeith Packard
3086edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig"
30875e8ebd84SJason A. Donenfeld
30885e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler"
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