xref: /linux/arch/x86/Kconfig (revision 0f1441b44e823a74f3f3780902a113e07c73fbf6)
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
17117ed454SThomas Gleixner	select HAVE_DEBUG_STACKOVERFLOW
18341c787eSIngo Molnar	select MODULES_USE_ELF_REL
19341c787eSIngo Molnar	select OLD_SIGACTION
207ac87074SVincenzo Frascino	select GENERIC_VDSO_32
21daa93fabSSam Ravnborg
22daa93fabSSam Ravnborgconfig X86_64
233120e25eSJan Beulich	def_bool y
243120e25eSJan Beulich	depends on 64BIT
25d94e0685SIngo Molnar	# Options that are inherently 64-bit kernel only:
264eb0716eSAlexandre Ghiti	select ARCH_HAS_GIGANTIC_PAGE
27c12d3362SArd Biesheuvel	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
28d94e0685SIngo Molnar	select ARCH_USE_CMPXCHG_LOCKREF
29d94e0685SIngo Molnar	select HAVE_ARCH_SOFT_DIRTY
30d94e0685SIngo Molnar	select MODULES_USE_ELF_RELA
31f616ab59SChristoph Hellwig	select NEED_DMA_MAP_STATE
3209230cbcSChristoph Hellwig	select SWIOTLB
331032c0baSSam Ravnborg
34518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE
35518049d9SSteven Rostedt (VMware)	def_bool y
36518049d9SSteven Rostedt (VMware)	depends on X86_32
37518049d9SSteven Rostedt (VMware)	depends on FUNCTION_TRACER
38518049d9SSteven Rostedt (VMware)	select DYNAMIC_FTRACE
39518049d9SSteven Rostedt (VMware)	help
40518049d9SSteven Rostedt (VMware)	 We keep the static function tracing (!DYNAMIC_FTRACE) around
41518049d9SSteven Rostedt (VMware)	 in order to test the non static function tracing in the
42518049d9SSteven Rostedt (VMware)	 generic code, as other architectures still use it. But we
43518049d9SSteven Rostedt (VMware)	 only need to keep it around for x86_64. No need to keep it
44518049d9SSteven Rostedt (VMware)	 for x86_32. For x86_32, force DYNAMIC_FTRACE.
45d94e0685SIngo Molnar#
46d94e0685SIngo Molnar# Arch settings
47d94e0685SIngo Molnar#
48d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be
49d94e0685SIngo Molnar#   ported to 32-bit as well. )
50d94e0685SIngo Molnar#
518d5fffb9SSam Ravnborgconfig X86
523c2362e6SHarvey Harrison	def_bool y
53c763ea26SIngo Molnar	#
54c763ea26SIngo Molnar	# Note: keep this list sorted alphabetically
55c763ea26SIngo Molnar	#
566471b825SIngo Molnar	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
576e0a0ea1SGraeme Gregory	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
58942fa985SYury Norov	select ARCH_32BIT_OFF_T			if X86_32
592a21ad57SThomas Gleixner	select ARCH_CLOCKSOURCE_INIT
6091dda51aSAleksey Makarov	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
61fa5b6ec9SLaura Abbott	select ARCH_HAS_DEBUG_VIRTUAL
62399145f9SAnshuman Khandual	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
6321266be9SDan Williams	select ARCH_HAS_DEVMEM_IS_ALLOWED
64b1a57bbfSDouglas Anderson	select ARCH_HAS_EARLY_DEBUG		if KGDB
656471b825SIngo Molnar	select ARCH_HAS_ELF_RANDOMIZE
6672d93104SLinus Torvalds	select ARCH_HAS_FAST_MULTIPLIER
67316d097cSDave Hansen	select ARCH_HAS_FILTER_PGPROT
686974f0c4SDaniel Micay	select ARCH_HAS_FORTIFY_SOURCE
69957e3facSRiku Voipio	select ARCH_HAS_GCOV_PROFILE_ALL
70*0f1441b4SPeter Zijlstra	select ARCH_HAS_KCOV			if X86_64 && STACK_VALIDATION
710c9c1d56SThiago Jung Bauermann	select ARCH_HAS_MEM_ENCRYPT
7210bcc80eSMathieu Desnoyers	select ARCH_HAS_MEMBARRIER_SYNC_CORE
730ebeea8cSDaniel Borkmann	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
74c763ea26SIngo Molnar	select ARCH_HAS_PMEM_API		if X86_64
7517596731SRobin Murphy	select ARCH_HAS_PTE_DEVMAP		if X86_64
763010a5eaSLaurent Dufour	select ARCH_HAS_PTE_SPECIAL
770aed55afSDan Williams	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
78092b31aaSDan Williams	select ARCH_HAS_UACCESS_MCSAFE		if X86_64 && X86_MCE
79d2852a22SDaniel Borkmann	select ARCH_HAS_SET_MEMORY
80d253ca0cSRick Edgecombe	select ARCH_HAS_SET_DIRECT_MAP
81ad21fc4fSLaura Abbott	select ARCH_HAS_STRICT_KERNEL_RWX
82ad21fc4fSLaura Abbott	select ARCH_HAS_STRICT_MODULE_RWX
83ac1ab12aSMathieu Desnoyers	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
8425c619e5SBrian Gerst	select ARCH_HAS_SYSCALL_WRAPPER
85c6d30853SAndrey Ryabinin	select ARCH_HAS_UBSAN_SANITIZE_ALL
867e01ccb4SZong Li	select ARCH_HAS_DEBUG_WX
876471b825SIngo Molnar	select ARCH_HAVE_NMI_SAFE_CMPXCHG
886471b825SIngo Molnar	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
8977fbbc81SMark Salter	select ARCH_MIGHT_HAVE_PC_PARPORT
905e2c18c0SMark Salter	select ARCH_MIGHT_HAVE_PC_SERIO
913599fe12SThomas Gleixner	select ARCH_STACKWALK
922c870e61SArnd Bergmann	select ARCH_SUPPORTS_ACPI
936471b825SIngo Molnar	select ARCH_SUPPORTS_ATOMIC_RMW
946471b825SIngo Molnar	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
956471b825SIngo Molnar	select ARCH_USE_BUILTIN_BSWAP
966471b825SIngo Molnar	select ARCH_USE_QUEUED_RWLOCKS
976471b825SIngo Molnar	select ARCH_USE_QUEUED_SPINLOCKS
982ce0d7f9SMark Brown	select ARCH_USE_SYM_ANNOTATIONS
99ce4a4e56SAndy Lutomirski	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
10081c22041SDaniel Borkmann	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
101c763ea26SIngo Molnar	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
1023876d4a3SAlexandre Ghiti	select ARCH_WANT_HUGE_PMD_SHARE
10338d8b4e6SHuang Ying	select ARCH_WANTS_THP_SWAP		if X86_64
10410916706SShile Zhang	select BUILDTIME_TABLE_SORT
1056471b825SIngo Molnar	select CLKEVT_I8253
1066471b825SIngo Molnar	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
1076471b825SIngo Molnar	select CLOCKSOURCE_WATCHDOG
1086471b825SIngo Molnar	select DCACHE_WORD_ACCESS
10945471cd9SLinus Torvalds	select EDAC_ATOMIC_SCRUB
11045471cd9SLinus Torvalds	select EDAC_SUPPORT
1116471b825SIngo Molnar	select GENERIC_CLOCKEVENTS
1126471b825SIngo Molnar	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
1136471b825SIngo Molnar	select GENERIC_CLOCKEVENTS_MIN_ADJUST
1146471b825SIngo Molnar	select GENERIC_CMOS_UPDATE
1156471b825SIngo Molnar	select GENERIC_CPU_AUTOPROBE
11661dc0f55SThomas Gleixner	select GENERIC_CPU_VULNERABILITIES
1176471b825SIngo Molnar	select GENERIC_EARLY_IOREMAP
1186471b825SIngo Molnar	select GENERIC_FIND_FIRST_BIT
1196471b825SIngo Molnar	select GENERIC_IOMAP
120c7d6c9ddSThomas Gleixner	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
1210fa115daSThomas Gleixner	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
122ad7a929fSThomas Gleixner	select GENERIC_IRQ_MIGRATION		if SMP
1236471b825SIngo Molnar	select GENERIC_IRQ_PROBE
124c201c917SThomas Gleixner	select GENERIC_IRQ_RESERVATION_MODE
1256471b825SIngo Molnar	select GENERIC_IRQ_SHOW
1266471b825SIngo Molnar	select GENERIC_PENDING_IRQ		if SMP
1272ae27137SSteven Price	select GENERIC_PTDUMP
1286471b825SIngo Molnar	select GENERIC_SMP_IDLE_THREAD
1296471b825SIngo Molnar	select GENERIC_STRNCPY_FROM_USER
1306471b825SIngo Molnar	select GENERIC_STRNLEN_USER
1316471b825SIngo Molnar	select GENERIC_TIME_VSYSCALL
1327ac87074SVincenzo Frascino	select GENERIC_GETTIMEOFDAY
133550a77a7SDmitry Safonov	select GENERIC_VDSO_TIME_NS
13439656e83SChristoph Hellwig	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
13517e5888eSHans de Goede	select HARDIRQS_SW_RESEND
1367edaeb68SThomas Gleixner	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
1376471b825SIngo Molnar	select HAVE_ACPI_APEI			if ACPI
1386471b825SIngo Molnar	select HAVE_ACPI_APEI_NMI		if ACPI
1396471b825SIngo Molnar	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
1406471b825SIngo Molnar	select HAVE_ARCH_AUDITSYSCALL
1416471b825SIngo Molnar	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
1426471b825SIngo Molnar	select HAVE_ARCH_JUMP_LABEL
143b34006c4SArd Biesheuvel	select HAVE_ARCH_JUMP_LABEL_RELATIVE
144d17a1d97SAndrey Ryabinin	select HAVE_ARCH_KASAN			if X86_64
1450609ae01SDaniel Axtens	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
1466471b825SIngo Molnar	select HAVE_ARCH_KGDB
1479e08f57dSDaniel Cashman	select HAVE_ARCH_MMAP_RND_BITS		if MMU
1489e08f57dSDaniel Cashman	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
1491b028f78SDmitry Safonov	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
150271ca788SArd Biesheuvel	select HAVE_ARCH_PREL32_RELOCATIONS
1516471b825SIngo Molnar	select HAVE_ARCH_SECCOMP_FILTER
152f7d83c1cSKees Cook	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
153afaef01cSAlexander Popov	select HAVE_ARCH_STACKLEAK
1546471b825SIngo Molnar	select HAVE_ARCH_TRACEHOOK
1556471b825SIngo Molnar	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
156a00cc7d9SMatthew Wilcox	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
157b64d8d1eSPeter Xu	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
158e37e43a4SAndy Lutomirski	select HAVE_ARCH_VMAP_STACK		if X86_64
159c763ea26SIngo Molnar	select HAVE_ARCH_WITHIN_STACK_FRAMES
1602ff2b7ecSMasahiro Yamada	select HAVE_ASM_MODVERSIONS
1616471b825SIngo Molnar	select HAVE_CMPXCHG_DOUBLE
1626471b825SIngo Molnar	select HAVE_CMPXCHG_LOCAL
1636471b825SIngo Molnar	select HAVE_CONTEXT_TRACKING		if X86_64
164c1bd55f9SJosh Triplett	select HAVE_COPY_THREAD_TLS
1656471b825SIngo Molnar	select HAVE_C_RECORDMCOUNT
1666471b825SIngo Molnar	select HAVE_DEBUG_KMEMLEAK
1679c5a3621SAkinobu Mita	select HAVE_DMA_CONTIGUOUS
168677aa9f7SSteven Rostedt	select HAVE_DYNAMIC_FTRACE
16906aeaaeaSMasami Hiramatsu	select HAVE_DYNAMIC_FTRACE_WITH_REGS
170562955feSSteven Rostedt (VMware)	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
17103f5781bSWang YanQing	select HAVE_EBPF_JIT
17258340a07SJohannes Berg	select HAVE_EFFICIENT_UNALIGNED_ACCESS
1736630a8e5SChristoph Hellwig	select HAVE_EISA
1745f56a5dfSJiri Slaby	select HAVE_EXIT_THREAD
17567a929e0SChristoph Hellwig	select HAVE_FAST_GUP
176644e0e8dSSteven Rostedt (VMware)	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
1776471b825SIngo Molnar	select HAVE_FTRACE_MCOUNT_RECORD
1786471b825SIngo Molnar	select HAVE_FUNCTION_GRAPH_TRACER
1796471b825SIngo Molnar	select HAVE_FUNCTION_TRACER
1806b90bd4bSEmese Revfy	select HAVE_GCC_PLUGINS
1810067f129SK.Prasad	select HAVE_HW_BREAKPOINT
1826471b825SIngo Molnar	select HAVE_IDE
1836471b825SIngo Molnar	select HAVE_IOREMAP_PROT
1846471b825SIngo Molnar	select HAVE_IRQ_TIME_ACCOUNTING
1856471b825SIngo Molnar	select HAVE_KERNEL_BZIP2
1866471b825SIngo Molnar	select HAVE_KERNEL_GZIP
1876471b825SIngo Molnar	select HAVE_KERNEL_LZ4
1886471b825SIngo Molnar	select HAVE_KERNEL_LZMA
1896471b825SIngo Molnar	select HAVE_KERNEL_LZO
1906471b825SIngo Molnar	select HAVE_KERNEL_XZ
1916471b825SIngo Molnar	select HAVE_KPROBES
1926471b825SIngo Molnar	select HAVE_KPROBES_ON_FTRACE
193540adea3SMasami Hiramatsu	select HAVE_FUNCTION_ERROR_INJECTION
1946471b825SIngo Molnar	select HAVE_KRETPROBES
1956471b825SIngo Molnar	select HAVE_KVM
1966471b825SIngo Molnar	select HAVE_LIVEPATCH			if X86_64
1970102752eSFrederic Weisbecker	select HAVE_MIXED_BREAKPOINTS_REGS
198ee9f8fceSJosh Poimboeuf	select HAVE_MOD_ARCH_SPECIFIC
1999f132f7eSJoel Fernandes (Google)	select HAVE_MOVE_PMD
20042a0bb3fSPetr Mladek	select HAVE_NMI
2016471b825SIngo Molnar	select HAVE_OPROFILE
2026471b825SIngo Molnar	select HAVE_OPTPROBES
2036471b825SIngo Molnar	select HAVE_PCSPKR_PLATFORM
2046471b825SIngo Molnar	select HAVE_PERF_EVENTS
205c01d4323SFrederic Weisbecker	select HAVE_PERF_EVENTS_NMI
20692e5aae4SNicholas Piggin	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
207eb01d42aSChristoph Hellwig	select HAVE_PCI
208c5e63197SJiri Olsa	select HAVE_PERF_REGS
209c5ebcedbSJiri Olsa	select HAVE_PERF_USER_STACK_DUMP
210ff2e6d72SPeter Zijlstra	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
2116471b825SIngo Molnar	select HAVE_REGS_AND_STACK_ACCESS_API
2126415b38bSJiri Slaby	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
2133c88ee19SMasami Hiramatsu	select HAVE_FUNCTION_ARG_ACCESS_API
214d148eac0SMasahiro Yamada	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
215c763ea26SIngo Molnar	select HAVE_STACK_VALIDATION		if X86_64
216d6761b8fSMathieu Desnoyers	select HAVE_RSEQ
2176471b825SIngo Molnar	select HAVE_SYSCALL_TRACEPOINTS
2186471b825SIngo Molnar	select HAVE_UNSTABLE_SCHED_CLOCK
2197c68af6eSAvi Kivity	select HAVE_USER_RETURN_NOTIFIER
2207ac87074SVincenzo Frascino	select HAVE_GENERIC_VDSO
22105736e4aSThomas Gleixner	select HOTPLUG_SMT			if SMP
222c0185808SThomas Gleixner	select IRQ_FORCED_THREADING
22386596f0aSChristoph Hellwig	select NEED_SG_DMA_LENGTH
2242eac9c2dSChristoph Hellwig	select PCI_DOMAINS			if PCI
225625210cfSSinan Kaya	select PCI_LOCKLESS_CONFIG		if PCI
2266471b825SIngo Molnar	select PERF_EVENTS
2273195ef59SPrarit Bhargava	select RTC_LIB
228d6faca40SArnd Bergmann	select RTC_MC146818_LIB
2296471b825SIngo Molnar	select SPARSE_IRQ
23083fe27eaSPranith Kumar	select SRCU
2316471b825SIngo Molnar	select SYSCTL_EXCEPTION_TRACE
23215f4eae7SAndy Lutomirski	select THREAD_INFO_IN_TASK
2336471b825SIngo Molnar	select USER_STACKTRACE_SUPPORT
2346471b825SIngo Molnar	select VIRT_TO_BUS
2353b02a051SIngo Molnar	select HAVE_ARCH_KCSAN			if X86_64
2366471b825SIngo Molnar	select X86_FEATURE_NAMES		if PROC_FS
2370c608dadSAubrey Li	select PROC_PID_ARCH_STATUS		if PROC_FS
2389e2b4be3SNayna Jain	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
2397d8330a5SBalbir Singh
240ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER
2413120e25eSJan Beulich	def_bool y
2423120e25eSJan Beulich	depends on KPROBES || PERF_EVENTS || UPROBES
243ba7e4d13SIngo Molnar
24451b26adaSLinus Torvaldsconfig OUTPUT_FORMAT
24551b26adaSLinus Torvalds	string
24651b26adaSLinus Torvalds	default "elf32-i386" if X86_32
24751b26adaSLinus Torvalds	default "elf64-x86-64" if X86_64
24851b26adaSLinus Torvalds
2498d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT
2503c2362e6SHarvey Harrison	def_bool y
2518d5fffb9SSam Ravnborg
2528d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT
2533c2362e6SHarvey Harrison	def_bool y
2548d5fffb9SSam Ravnborg
2558d5fffb9SSam Ravnborgconfig MMU
2563c2362e6SHarvey Harrison	def_bool y
2578d5fffb9SSam Ravnborg
2589e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN
2599e08f57dSDaniel Cashman	default 28 if 64BIT
2609e08f57dSDaniel Cashman	default 8
2619e08f57dSDaniel Cashman
2629e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX
2639e08f57dSDaniel Cashman	default 32 if 64BIT
2649e08f57dSDaniel Cashman	default 16
2659e08f57dSDaniel Cashman
2669e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN
2679e08f57dSDaniel Cashman	default 8
2689e08f57dSDaniel Cashman
2699e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX
2709e08f57dSDaniel Cashman	default 16
2719e08f57dSDaniel Cashman
2728d5fffb9SSam Ravnborgconfig SBUS
2738d5fffb9SSam Ravnborg	bool
2748d5fffb9SSam Ravnborg
2758d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA
2763120e25eSJan Beulich	def_bool y
2773120e25eSJan Beulich	depends on ISA_DMA_API
2788d5fffb9SSam Ravnborg
2798d5fffb9SSam Ravnborgconfig GENERIC_BUG
2803c2362e6SHarvey Harrison	def_bool y
2818d5fffb9SSam Ravnborg	depends on BUG
282b93a531eSJan Beulich	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
283b93a531eSJan Beulich
284b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS
285b93a531eSJan Beulich	bool
2868d5fffb9SSam Ravnborg
2878d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC
2883120e25eSJan Beulich	def_bool y
2893120e25eSJan Beulich	depends on ISA_DMA_API
2908d5fffb9SSam Ravnborg
2911032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY
2921032c0baSSam Ravnborg	def_bool y
2931032c0baSSam Ravnborg
2949a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX
2959a0b8415Svenkatesh.pallipadi@intel.com	def_bool y
2968d5fffb9SSam Ravnborg
2971b27d05bSPekka Enbergconfig ARCH_HAS_CACHE_LINE_SIZE
2981b27d05bSPekka Enberg	def_bool y
2991b27d05bSPekka Enberg
300316d097cSDave Hansenconfig ARCH_HAS_FILTER_PGPROT
301316d097cSDave Hansen	def_bool y
302316d097cSDave Hansen
303dd5af90aSMike Travisconfig HAVE_SETUP_PER_CPU_AREA
30489c9c4c5SBrian Gerst	def_bool y
305b32ef636Stravis@sgi.com
30608fc4580STejun Heoconfig NEED_PER_CPU_EMBED_FIRST_CHUNK
30708fc4580STejun Heo	def_bool y
30808fc4580STejun Heo
30908fc4580STejun Heoconfig NEED_PER_CPU_PAGE_FIRST_CHUNK
31011124411STejun Heo	def_bool y
31111124411STejun Heo
312801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE
313801e4062SJohannes Berg	def_bool y
314801e4062SJohannes Berg
315f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE
316f4cb5700SJohannes Berg	def_bool y
317f4cb5700SJohannes Berg
31853313b2cSSteve Capperconfig ARCH_WANT_GENERAL_HUGETLB
31953313b2cSSteve Capper	def_bool y
32053313b2cSSteve Capper
3218d5fffb9SSam Ravnborgconfig ZONE_DMA32
322e0fd24a3SJan Beulich	def_bool y if X86_64
3238d5fffb9SSam Ravnborg
3248d5fffb9SSam Ravnborgconfig AUDIT_ARCH
325e0fd24a3SJan Beulich	def_bool y if X86_64
3268d5fffb9SSam Ravnborg
3276a11f75bSAkinobu Mitaconfig ARCH_SUPPORTS_DEBUG_PAGEALLOC
3286a11f75bSAkinobu Mita	def_bool y
3296a11f75bSAkinobu Mita
330d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET
331d6f2d75aSAndrey Ryabinin	hex
332d6f2d75aSAndrey Ryabinin	depends on KASAN
333d6f2d75aSAndrey Ryabinin	default 0xdffffc0000000000
334d6f2d75aSAndrey Ryabinin
33569575d38SShane Wangconfig HAVE_INTEL_TXT
33669575d38SShane Wang	def_bool y
3376ea30386SKees Cook	depends on INTEL_IOMMU && ACPI
33869575d38SShane Wang
3396b0c3d44SSam Ravnborgconfig X86_32_SMP
3406b0c3d44SSam Ravnborg	def_bool y
3416b0c3d44SSam Ravnborg	depends on X86_32 && SMP
3426b0c3d44SSam Ravnborg
3436b0c3d44SSam Ravnborgconfig X86_64_SMP
3446b0c3d44SSam Ravnborg	def_bool y
3456b0c3d44SSam Ravnborg	depends on X86_64 && SMP
3466b0c3d44SSam Ravnborg
347ccbeed3aSTejun Heoconfig X86_32_LAZY_GS
348ccbeed3aSTejun Heo	def_bool y
3498458f8c2SMasahiro Yamada	depends on X86_32 && !STACKPROTECTOR
350ccbeed3aSTejun Heo
3512b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES
3522b144498SSrikar Dronamraju	def_bool y
3532b144498SSrikar Dronamraju
354d20642f0SRob Herringconfig FIX_EARLYCON_MEM
355d20642f0SRob Herring	def_bool y
356d20642f0SRob Herring
35794d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK
35894d49eb3SKirill A. Shutemov	bool
35994d49eb3SKirill A. Shutemov
36098233368SKirill A. Shutemovconfig PGTABLE_LEVELS
36198233368SKirill A. Shutemov	int
36277ef56e4SKirill A. Shutemov	default 5 if X86_5LEVEL
36398233368SKirill A. Shutemov	default 4 if X86_64
36498233368SKirill A. Shutemov	default 3 if X86_PAE
36598233368SKirill A. Shutemov	default 2
36698233368SKirill A. Shutemov
3672a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR
3682a61f474SMasahiro Yamada	bool
3692a61f474SMasahiro Yamada	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
3702a61f474SMasahiro Yamada	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
3712a61f474SMasahiro Yamada	help
3722a61f474SMasahiro Yamada	   We have to make sure stack protector is unconditionally disabled if
3732a61f474SMasahiro Yamada	   the compiler produces broken code.
3742a61f474SMasahiro Yamada
375506f1d07SSam Ravnborgmenu "Processor type and features"
376506f1d07SSam Ravnborg
3775ee71535SRandy Dunlapconfig ZONE_DMA
3785ee71535SRandy Dunlap	bool "DMA memory allocation support" if EXPERT
3795ee71535SRandy Dunlap	default y
3805ee71535SRandy Dunlap	help
3815ee71535SRandy Dunlap	  DMA memory allocation support allows devices with less than 32-bit
3825ee71535SRandy Dunlap	  addressing to allocate within the first 16MB of address space.
3835ee71535SRandy Dunlap	  Disable if no such devices will be used.
3845ee71535SRandy Dunlap
3855ee71535SRandy Dunlap	  If unsure, say Y.
3865ee71535SRandy Dunlap
387506f1d07SSam Ravnborgconfig SMP
388506f1d07SSam Ravnborg	bool "Symmetric multi-processing support"
389a7f7f624SMasahiro Yamada	help
390506f1d07SSam Ravnborg	  This enables support for systems with more than one CPU. If you have
3914a474157SRobert Graffham	  a system with only one CPU, say N. If you have a system with more
3924a474157SRobert Graffham	  than one CPU, say Y.
393506f1d07SSam Ravnborg
3944a474157SRobert Graffham	  If you say N here, the kernel will run on uni- and multiprocessor
395506f1d07SSam Ravnborg	  machines, but will use only one CPU of a multiprocessor machine. If
396506f1d07SSam Ravnborg	  you say Y here, the kernel will run on many, but not all,
3974a474157SRobert Graffham	  uniprocessor machines. On a uniprocessor machine, the kernel
398506f1d07SSam Ravnborg	  will run faster if you say N here.
399506f1d07SSam Ravnborg
400506f1d07SSam Ravnborg	  Note that if you say Y here and choose architecture "586" or
401506f1d07SSam Ravnborg	  "Pentium" under "Processor family", the kernel will not work on 486
402506f1d07SSam Ravnborg	  architectures. Similarly, multiprocessor kernels for the "PPro"
403506f1d07SSam Ravnborg	  architecture may not work on all Pentium based boards.
404506f1d07SSam Ravnborg
405506f1d07SSam Ravnborg	  People using multiprocessor machines who say Y here should also say
406506f1d07SSam Ravnborg	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
407506f1d07SSam Ravnborg	  Management" code will be disabled if you say Y here.
408506f1d07SSam Ravnborg
409cb1aaebeSMauro Carvalho Chehab	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
4104f4cfa6cSMauro Carvalho Chehab	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
411506f1d07SSam Ravnborg	  <http://www.tldp.org/docs.html#howto>.
412506f1d07SSam Ravnborg
413506f1d07SSam Ravnborg	  If you don't know what to do here, say N.
414506f1d07SSam Ravnborg
4159def39beSJosh Triplettconfig X86_FEATURE_NAMES
4169def39beSJosh Triplett	bool "Processor feature human-readable names" if EMBEDDED
4179def39beSJosh Triplett	default y
418a7f7f624SMasahiro Yamada	help
4199def39beSJosh Triplett	  This option compiles in a table of x86 feature bits and corresponding
4209def39beSJosh Triplett	  names.  This is required to support /proc/cpuinfo and a few kernel
4219def39beSJosh Triplett	  messages.  You can disable this to save space, at the expense of
4229def39beSJosh Triplett	  making those few kernel messages show numeric feature bits instead.
4239def39beSJosh Triplett
4249def39beSJosh Triplett	  If in doubt, say Y.
4259def39beSJosh Triplett
42606cd9a7dSYinghai Luconfig X86_X2APIC
42706cd9a7dSYinghai Lu	bool "Support x2apic"
42819e3d60dSJan Kiszka	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
429a7f7f624SMasahiro Yamada	help
43006cd9a7dSYinghai Lu	  This enables x2apic support on CPUs that have this feature.
43106cd9a7dSYinghai Lu
43206cd9a7dSYinghai Lu	  This allows 32-bit apic IDs (so it can support very large systems),
43306cd9a7dSYinghai Lu	  and accesses the local apic via MSRs not via mmio.
43406cd9a7dSYinghai Lu
43506cd9a7dSYinghai Lu	  If you don't know what to do here, say N.
43606cd9a7dSYinghai Lu
4376695c85bSYinghai Luconfig X86_MPPARSE
4386e87f9b7SBin Gao	bool "Enable MPS table" if ACPI || SFI
4397a527688SJan Beulich	default y
4405ab74722SIngo Molnar	depends on X86_LOCAL_APIC
441a7f7f624SMasahiro Yamada	help
4426695c85bSYinghai Lu	  For old smp systems that do not have proper acpi support. Newer systems
4436695c85bSYinghai Lu	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
4446695c85bSYinghai Lu
445ddd70cf9SJun Nakajimaconfig GOLDFISH
446ddd70cf9SJun Nakajima	def_bool y
447ddd70cf9SJun Nakajima	depends on X86_GOLDFISH
448ddd70cf9SJun Nakajima
44976b04384SDavid Woodhouseconfig RETPOLINE
45076b04384SDavid Woodhouse	bool "Avoid speculative indirect branches in kernel"
45176b04384SDavid Woodhouse	default y
452d5028ba8SPeter Zijlstra	select STACK_VALIDATION if HAVE_STACK_VALIDATION
45376b04384SDavid Woodhouse	help
45476b04384SDavid Woodhouse	  Compile kernel with the retpoline compiler options to guard against
45576b04384SDavid Woodhouse	  kernel-to-user data leaks by avoiding speculative indirect
45676b04384SDavid Woodhouse	  branches. Requires a compiler with -mindirect-branch=thunk-extern
45776b04384SDavid Woodhouse	  support for full protection. The kernel may run slower.
45876b04384SDavid Woodhouse
459e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL
460e6d42931SJohannes Weiner	bool "x86 CPU resource control support"
4616fe07ce3SBabu Moger	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
46259fe5a77SThomas Gleixner	select KERNFS
463e79f15a4SChen Yu	select PROC_CPU_RESCTRL		if PROC_FS
46478e99b4aSFenghua Yu	help
465e6d42931SJohannes Weiner	  Enable x86 CPU resource control support.
4666fe07ce3SBabu Moger
4676fe07ce3SBabu Moger	  Provide support for the allocation and monitoring of system resources
4686fe07ce3SBabu Moger	  usage by the CPU.
4696fe07ce3SBabu Moger
4706fe07ce3SBabu Moger	  Intel calls this Intel Resource Director Technology
4716fe07ce3SBabu Moger	  (Intel(R) RDT). More information about RDT can be found in the
4726fe07ce3SBabu Moger	  Intel x86 Architecture Software Developer Manual.
4736fe07ce3SBabu Moger
4746fe07ce3SBabu Moger	  AMD calls this AMD Platform Quality of Service (AMD QoS).
4756fe07ce3SBabu Moger	  More information about AMD QoS can be found in the AMD64 Technology
4766fe07ce3SBabu Moger	  Platform Quality of Service Extensions manual.
47778e99b4aSFenghua Yu
47878e99b4aSFenghua Yu	  Say N if unsure.
47978e99b4aSFenghua Yu
4808425091fSRavikiran G Thirumalaiif X86_32
481a0d0bb4dSRandy Dunlapconfig X86_BIGSMP
482a0d0bb4dSRandy Dunlap	bool "Support for big SMP systems with more than 8 CPUs"
483a0d0bb4dSRandy Dunlap	depends on SMP
484a7f7f624SMasahiro Yamada	help
485e133f6eaSRandy Dunlap	  This option is needed for the systems that have more than 8 CPUs.
486a0d0bb4dSRandy Dunlap
487c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM
488c5c606d9SRavikiran G Thirumalai	bool "Support for extended (non-PC) x86 platforms"
489c5c606d9SRavikiran G Thirumalai	default y
490a7f7f624SMasahiro Yamada	help
49106ac8346SIngo Molnar	  If you disable this option then the kernel will only support
49206ac8346SIngo Molnar	  standard PC platforms. (which covers the vast majority of
49306ac8346SIngo Molnar	  systems out there.)
49406ac8346SIngo Molnar
4958425091fSRavikiran G Thirumalai	  If you enable this option then you'll be able to select support
4968425091fSRavikiran G Thirumalai	  for the following (non-PC) 32 bit x86 platforms:
497cb7b8023SBen Hutchings		Goldfish (Android emulator)
4988425091fSRavikiran G Thirumalai		AMD Elan
4998425091fSRavikiran G Thirumalai		RDC R-321x SoC
5008425091fSRavikiran G Thirumalai		SGI 320/540 (Visual Workstation)
50183125a3aSAlessandro Rubini		STA2X11-based (e.g. Northville)
5023f4110a4SThomas Gleixner		Moorestown MID devices
50306ac8346SIngo Molnar
50406ac8346SIngo Molnar	  If you have one of these systems, or if you want to build a
50506ac8346SIngo Molnar	  generic distribution kernel, say Y here - otherwise say N.
5068425091fSRavikiran G Thirumalaiendif
50706ac8346SIngo Molnar
5088425091fSRavikiran G Thirumalaiif X86_64
5098425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM
5108425091fSRavikiran G Thirumalai	bool "Support for extended (non-PC) x86 platforms"
5118425091fSRavikiran G Thirumalai	default y
512a7f7f624SMasahiro Yamada	help
5138425091fSRavikiran G Thirumalai	  If you disable this option then the kernel will only support
5148425091fSRavikiran G Thirumalai	  standard PC platforms. (which covers the vast majority of
5158425091fSRavikiran G Thirumalai	  systems out there.)
5168425091fSRavikiran G Thirumalai
5178425091fSRavikiran G Thirumalai	  If you enable this option then you'll be able to select support
5188425091fSRavikiran G Thirumalai	  for the following (non-PC) 64 bit x86 platforms:
51944b111b5SSteffen Persvold		Numascale NumaChip
5208425091fSRavikiran G Thirumalai		ScaleMP vSMP
5218425091fSRavikiran G Thirumalai		SGI Ultraviolet
5228425091fSRavikiran G Thirumalai
5238425091fSRavikiran G Thirumalai	  If you have one of these systems, or if you want to build a
5248425091fSRavikiran G Thirumalai	  generic distribution kernel, say Y here - otherwise say N.
5258425091fSRavikiran G Thirumalaiendif
526c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms
527c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions
52844b111b5SSteffen Persvoldconfig X86_NUMACHIP
52944b111b5SSteffen Persvold	bool "Numascale NumaChip"
53044b111b5SSteffen Persvold	depends on X86_64
53144b111b5SSteffen Persvold	depends on X86_EXTENDED_PLATFORM
53244b111b5SSteffen Persvold	depends on NUMA
53344b111b5SSteffen Persvold	depends on SMP
53444b111b5SSteffen Persvold	depends on X86_X2APIC
535f9726bfdSDaniel J Blueman	depends on PCI_MMCONFIG
536a7f7f624SMasahiro Yamada	help
53744b111b5SSteffen Persvold	  Adds support for Numascale NumaChip large-SMP systems. Needed to
53844b111b5SSteffen Persvold	  enable more than ~168 cores.
53944b111b5SSteffen Persvold	  If you don't have one of these, you should say N here.
54003b48632SNick Piggin
5416a48565eSIngo Molnarconfig X86_VSMP
542c5c606d9SRavikiran G Thirumalai	bool "ScaleMP vSMP"
5436276a074SBorislav Petkov	select HYPERVISOR_GUEST
5446a48565eSIngo Molnar	select PARAVIRT
5456a48565eSIngo Molnar	depends on X86_64 && PCI
546c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
547ead91d4bSShai Fultheim	depends on SMP
548a7f7f624SMasahiro Yamada	help
5496a48565eSIngo Molnar	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
5506a48565eSIngo Molnar	  supposed to run on these EM64T-based machines.  Only choose this option
5516a48565eSIngo Molnar	  if you have one of these machines.
5526a48565eSIngo Molnar
553c5c606d9SRavikiran G Thirumalaiconfig X86_UV
554c5c606d9SRavikiran G Thirumalai	bool "SGI Ultraviolet"
555c5c606d9SRavikiran G Thirumalai	depends on X86_64
556c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
55754c28d29SJack Steiner	depends on NUMA
5581ecb4ae5SAndrew Morton	depends on EFI
5599d6c26e7SSuresh Siddha	depends on X86_X2APIC
5601222e564SIngo Molnar	depends on PCI
561a7f7f624SMasahiro Yamada	help
562c5c606d9SRavikiran G Thirumalai	  This option is needed in order to support SGI Ultraviolet systems.
563c5c606d9SRavikiran G Thirumalai	  If you don't have one of these, you should say N here.
564c5c606d9SRavikiran G Thirumalai
565c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms
566c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions
567506f1d07SSam Ravnborg
568ddd70cf9SJun Nakajimaconfig X86_GOLDFISH
569ddd70cf9SJun Nakajima	bool "Goldfish (Virtual Platform)"
570cb7b8023SBen Hutchings	depends on X86_EXTENDED_PLATFORM
571a7f7f624SMasahiro Yamada	help
572ddd70cf9SJun Nakajima	 Enable support for the Goldfish virtual platform used primarily
573ddd70cf9SJun Nakajima	 for Android development. Unless you are building for the Android
574ddd70cf9SJun Nakajima	 Goldfish emulator say N here.
575ddd70cf9SJun Nakajima
576c751e17bSThomas Gleixnerconfig X86_INTEL_CE
577c751e17bSThomas Gleixner	bool "CE4100 TV platform"
578c751e17bSThomas Gleixner	depends on PCI
579c751e17bSThomas Gleixner	depends on PCI_GODIRECT
5806084a6e2SJiang Liu	depends on X86_IO_APIC
581c751e17bSThomas Gleixner	depends on X86_32
582c751e17bSThomas Gleixner	depends on X86_EXTENDED_PLATFORM
58337bc9f50SDirk Brandewie	select X86_REBOOTFIXUPS
584da6b737bSSebastian Andrzej Siewior	select OF
585da6b737bSSebastian Andrzej Siewior	select OF_EARLY_FLATTREE
586a7f7f624SMasahiro Yamada	help
587c751e17bSThomas Gleixner	  Select for the Intel CE media processor (CE4100) SOC.
588c751e17bSThomas Gleixner	  This option compiles in support for the CE4100 SOC for settop
589c751e17bSThomas Gleixner	  boxes and media devices.
590c751e17bSThomas Gleixner
5914cb9b00fSDavid Cohenconfig X86_INTEL_MID
59243605ef1SAlan Cox	bool "Intel MID platform support"
59343605ef1SAlan Cox	depends on X86_EXTENDED_PLATFORM
594edc6bc78SDavid Cohen	depends on X86_PLATFORM_DEVICES
5951ea7c673SAlan Cox	depends on PCI
5963fda5bb4SAndy Shevchenko	depends on X86_64 || (PCI_GOANY && X86_32)
5971ea7c673SAlan Cox	depends on X86_IO_APIC
5987c9c3a1eSAlan Cox	select SFI
5994cb9b00fSDavid Cohen	select I2C
6007c9c3a1eSAlan Cox	select DW_APB_TIMER
6011ea7c673SAlan Cox	select APB_TIMER
60254b34aa0SMika Westerberg	select INTEL_SCU_PCI
60315a713dfSMika Westerberg	select MFD_INTEL_MSIC
604a7f7f624SMasahiro Yamada	help
6054cb9b00fSDavid Cohen	  Select to build a kernel capable of supporting Intel MID (Mobile
6064cb9b00fSDavid Cohen	  Internet Device) platform systems which do not have the PCI legacy
6074cb9b00fSDavid Cohen	  interfaces. If you are building for a PC class system say N here.
6081ea7c673SAlan Cox
6094cb9b00fSDavid Cohen	  Intel MID platforms are based on an Intel processor and chipset which
6104cb9b00fSDavid Cohen	  consume less power than most of the x86 derivatives.
61143605ef1SAlan Cox
6128bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK
6138bbc2a13SBryan O'Donoghue	bool "Intel Quark platform support"
6148bbc2a13SBryan O'Donoghue	depends on X86_32
6158bbc2a13SBryan O'Donoghue	depends on X86_EXTENDED_PLATFORM
6168bbc2a13SBryan O'Donoghue	depends on X86_PLATFORM_DEVICES
6178bbc2a13SBryan O'Donoghue	depends on X86_TSC
6188bbc2a13SBryan O'Donoghue	depends on PCI
6198bbc2a13SBryan O'Donoghue	depends on PCI_GOANY
6208bbc2a13SBryan O'Donoghue	depends on X86_IO_APIC
6218bbc2a13SBryan O'Donoghue	select IOSF_MBI
6228bbc2a13SBryan O'Donoghue	select INTEL_IMR
6239ab6eb51SAndy Shevchenko	select COMMON_CLK
624a7f7f624SMasahiro Yamada	help
6258bbc2a13SBryan O'Donoghue	  Select to include support for Quark X1000 SoC.
6268bbc2a13SBryan O'Donoghue	  Say Y here if you have a Quark based system such as the Arduino
6278bbc2a13SBryan O'Donoghue	  compatible Intel Galileo.
6288bbc2a13SBryan O'Donoghue
6293d48aab1SMika Westerbergconfig X86_INTEL_LPSS
6303d48aab1SMika Westerberg	bool "Intel Low Power Subsystem Support"
6315962dd22SSinan Kaya	depends on X86 && ACPI && PCI
6323d48aab1SMika Westerberg	select COMMON_CLK
6330f531431SMathias Nyman	select PINCTRL
634eebb3e8dSAndy Shevchenko	select IOSF_MBI
635a7f7f624SMasahiro Yamada	help
6363d48aab1SMika Westerberg	  Select to build support for Intel Low Power Subsystem such as
6373d48aab1SMika Westerberg	  found on Intel Lynxpoint PCH. Selecting this option enables
6380f531431SMathias Nyman	  things like clock tree (common clock framework) and pincontrol
6390f531431SMathias Nyman	  which are needed by the LPSS peripheral drivers.
6403d48aab1SMika Westerberg
64192082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE
64292082a88SKen Xue	bool "AMD ACPI2Platform devices support"
64392082a88SKen Xue	depends on ACPI
64492082a88SKen Xue	select COMMON_CLK
64592082a88SKen Xue	select PINCTRL
646a7f7f624SMasahiro Yamada	help
64792082a88SKen Xue	  Select to interpret AMD specific ACPI device to platform device
64892082a88SKen Xue	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
64992082a88SKen Xue	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
65092082a88SKen Xue	  implemented under PINCTRL subsystem.
65192082a88SKen Xue
652ced3ce76SDavid E. Boxconfig IOSF_MBI
653ced3ce76SDavid E. Box	tristate "Intel SoC IOSF Sideband support for SoC platforms"
654ced3ce76SDavid E. Box	depends on PCI
655a7f7f624SMasahiro Yamada	help
656ced3ce76SDavid E. Box	  This option enables sideband register access support for Intel SoC
657ced3ce76SDavid E. Box	  platforms. On these platforms the IOSF sideband is used in lieu of
658ced3ce76SDavid E. Box	  MSR's for some register accesses, mostly but not limited to thermal
659ced3ce76SDavid E. Box	  and power. Drivers may query the availability of this device to
660ced3ce76SDavid E. Box	  determine if they need the sideband in order to work on these
661ced3ce76SDavid E. Box	  platforms. The sideband is available on the following SoC products.
662ced3ce76SDavid E. Box	  This list is not meant to be exclusive.
663ced3ce76SDavid E. Box	   - BayTrail
664ced3ce76SDavid E. Box	   - Braswell
665ced3ce76SDavid E. Box	   - Quark
666ced3ce76SDavid E. Box
667ced3ce76SDavid E. Box	  You should say Y if you are running a kernel on one of these SoC's.
668ced3ce76SDavid E. Box
669ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG
670ed2226bdSDavid E. Box	bool "Enable IOSF sideband access through debugfs"
671ed2226bdSDavid E. Box	depends on IOSF_MBI && DEBUG_FS
672a7f7f624SMasahiro Yamada	help
673ed2226bdSDavid E. Box	  Select this option to expose the IOSF sideband access registers (MCR,
674ed2226bdSDavid E. Box	  MDR, MCRX) through debugfs to write and read register information from
675ed2226bdSDavid E. Box	  different units on the SoC. This is most useful for obtaining device
676ed2226bdSDavid E. Box	  state information for debug and analysis. As this is a general access
677ed2226bdSDavid E. Box	  mechanism, users of this option would have specific knowledge of the
678ed2226bdSDavid E. Box	  device they want to access.
679ed2226bdSDavid E. Box
680ed2226bdSDavid E. Box	  If you don't require the option or are in doubt, say N.
681ed2226bdSDavid E. Box
682c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X
683c5c606d9SRavikiran G Thirumalai	bool "RDC R-321x SoC"
684506f1d07SSam Ravnborg	depends on X86_32
685c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
686c5c606d9SRavikiran G Thirumalai	select M486
687c5c606d9SRavikiran G Thirumalai	select X86_REBOOTFIXUPS
688a7f7f624SMasahiro Yamada	help
689c5c606d9SRavikiran G Thirumalai	  This option is needed for RDC R-321x system-on-chip, also known
690c5c606d9SRavikiran G Thirumalai	  as R-8610-(G).
691c5c606d9SRavikiran G Thirumalai	  If you don't have one of these chips, you should say N here.
692c5c606d9SRavikiran G Thirumalai
693e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD
6949c398017SIngo Molnar	bool "Support non-standard 32-bit SMP architectures"
6959c398017SIngo Molnar	depends on X86_32 && SMP
696c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
697a7f7f624SMasahiro Yamada	help
698b5660ba7SH. Peter Anvin	  This option compiles in the bigsmp and STA2X11 default
699b5660ba7SH. Peter Anvin	  subarchitectures.  It is intended for a generic binary
700b5660ba7SH. Peter Anvin	  kernel. If you select them all, kernel will probe it one by
701b5660ba7SH. Peter Anvin	  one and will fallback to default.
702d49c4288SYinghai Lu
703c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms
704d49c4288SYinghai Lu
705d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE
7066fc108a0SJan Beulich	def_bool y
707d949f36fSLinus Torvalds	# MCE code calls memory_failure():
708d949f36fSLinus Torvalds	depends on X86_MCE
709d949f36fSLinus Torvalds	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
710d949f36fSLinus Torvalds	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
711d949f36fSLinus Torvalds	depends on X86_64 || !SPARSEMEM
712d949f36fSLinus Torvalds	select ARCH_SUPPORTS_MEMORY_FAILURE
713d949f36fSLinus Torvalds
71483125a3aSAlessandro Rubiniconfig STA2X11
71583125a3aSAlessandro Rubini	bool "STA2X11 Companion Chip Support"
71683125a3aSAlessandro Rubini	depends on X86_32_NON_STANDARD && PCI
71783125a3aSAlessandro Rubini	select SWIOTLB
71883125a3aSAlessandro Rubini	select MFD_STA2X11
7190145071bSLinus Walleij	select GPIOLIB
720a7f7f624SMasahiro Yamada	help
72183125a3aSAlessandro Rubini	  This adds support for boards based on the STA2X11 IO-Hub,
72283125a3aSAlessandro Rubini	  a.k.a. "ConneXt". The chip is used in place of the standard
72383125a3aSAlessandro Rubini	  PC chipset, so all "standard" peripherals are missing. If this
72483125a3aSAlessandro Rubini	  option is selected the kernel will still be able to boot on
72583125a3aSAlessandro Rubini	  standard PC machines.
72683125a3aSAlessandro Rubini
72782148d1dSShérabconfig X86_32_IRIS
72882148d1dSShérab	tristate "Eurobraille/Iris poweroff module"
72982148d1dSShérab	depends on X86_32
730a7f7f624SMasahiro Yamada	help
73182148d1dSShérab	  The Iris machines from EuroBraille do not have APM or ACPI support
73282148d1dSShérab	  to shut themselves down properly.  A special I/O sequence is
73382148d1dSShérab	  needed to do so, which is what this module does at
73482148d1dSShérab	  kernel shutdown.
73582148d1dSShérab
73682148d1dSShérab	  This is only for Iris machines from EuroBraille.
73782148d1dSShérab
73882148d1dSShérab	  If unused, say N.
73982148d1dSShérab
740ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER
7413c2362e6SHarvey Harrison	def_bool y
7423c2362e6SHarvey Harrison	prompt "Single-depth WCHAN output"
743a87d0914SKen Chen	depends on X86
744a7f7f624SMasahiro Yamada	help
745506f1d07SSam Ravnborg	  Calculate simpler /proc/<PID>/wchan values. If this option
746506f1d07SSam Ravnborg	  is disabled then wchan values will recurse back to the
747506f1d07SSam Ravnborg	  caller function. This provides more accurate wchan values,
748506f1d07SSam Ravnborg	  at the expense of slightly more scheduling overhead.
749506f1d07SSam Ravnborg
750506f1d07SSam Ravnborg	  If in doubt, say "Y".
751506f1d07SSam Ravnborg
7526276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST
7536276a074SBorislav Petkov	bool "Linux guest support"
754a7f7f624SMasahiro Yamada	help
7556276a074SBorislav Petkov	  Say Y here to enable options for running Linux under various hyper-
7566276a074SBorislav Petkov	  visors. This option enables basic hypervisor detection and platform
7576276a074SBorislav Petkov	  setup.
758506f1d07SSam Ravnborg
7596276a074SBorislav Petkov	  If you say N, all options in this submenu will be skipped and
7606276a074SBorislav Petkov	  disabled, and Linux guest support won't be built in.
761506f1d07SSam Ravnborg
7626276a074SBorislav Petkovif HYPERVISOR_GUEST
763506f1d07SSam Ravnborg
764e61bd94aSEduardo Pereira Habkostconfig PARAVIRT
765e61bd94aSEduardo Pereira Habkost	bool "Enable paravirtualization code"
766a7f7f624SMasahiro Yamada	help
767e61bd94aSEduardo Pereira Habkost	  This changes the kernel so it can modify itself when it is run
768e61bd94aSEduardo Pereira Habkost	  under a hypervisor, potentially improving performance significantly
769e61bd94aSEduardo Pereira Habkost	  over full virtualization.  However, when run without a hypervisor
770e61bd94aSEduardo Pereira Habkost	  the kernel is theoretically slower and slightly larger.
771e61bd94aSEduardo Pereira Habkost
772c00a280aSJuergen Grossconfig PARAVIRT_XXL
773c00a280aSJuergen Gross	bool
774c00a280aSJuergen Gross
7756276a074SBorislav Petkovconfig PARAVIRT_DEBUG
7766276a074SBorislav Petkov	bool "paravirt-ops debugging"
7776276a074SBorislav Petkov	depends on PARAVIRT && DEBUG_KERNEL
778a7f7f624SMasahiro Yamada	help
7796276a074SBorislav Petkov	  Enable to debug paravirt_ops internals.  Specifically, BUG if
7806276a074SBorislav Petkov	  a paravirt_op is missing when it is called.
7816276a074SBorislav Petkov
782b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS
783b4ecc126SJeremy Fitzhardinge	bool "Paravirtualization layer for spinlocks"
7846ea30386SKees Cook	depends on PARAVIRT && SMP
785a7f7f624SMasahiro Yamada	help
786b4ecc126SJeremy Fitzhardinge	  Paravirtualized spinlocks allow a pvops backend to replace the
787b4ecc126SJeremy Fitzhardinge	  spinlock implementation with something virtualization-friendly
788b4ecc126SJeremy Fitzhardinge	  (for example, block the virtual CPU rather than spinning).
789b4ecc126SJeremy Fitzhardinge
7904c4e4f61SRaghavendra K T	  It has a minimal impact on native kernels and gives a nice performance
7914c4e4f61SRaghavendra K T	  benefit on paravirtualized KVM / Xen kernels.
792b4ecc126SJeremy Fitzhardinge
7934c4e4f61SRaghavendra K T	  If you are unsure how to answer this question, answer Y.
794b4ecc126SJeremy Fitzhardinge
795ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR
796ecca2502SZhao Yakui	def_bool n
797ecca2502SZhao Yakui
7986276a074SBorislav Petkovsource "arch/x86/xen/Kconfig"
7996276a074SBorislav Petkov
8006276a074SBorislav Petkovconfig KVM_GUEST
8016276a074SBorislav Petkov	bool "KVM Guest support (including kvmclock)"
8026276a074SBorislav Petkov	depends on PARAVIRT
8036276a074SBorislav Petkov	select PARAVIRT_CLOCK
804a1c4423bSMarcelo Tosatti	select ARCH_CPUIDLE_HALTPOLL
8056276a074SBorislav Petkov	default y
806a7f7f624SMasahiro Yamada	help
8076276a074SBorislav Petkov	  This option enables various optimizations for running under the KVM
8086276a074SBorislav Petkov	  hypervisor. It includes a paravirtualized clock, so that instead
8096276a074SBorislav Petkov	  of relying on a PIT (or probably other) emulation by the
8106276a074SBorislav Petkov	  underlying device model, the host provides the guest with
8116276a074SBorislav Petkov	  timing infrastructure such as time of day, and system time
8126276a074SBorislav Petkov
813a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL
814a1c4423bSMarcelo Tosatti	def_bool n
815a1c4423bSMarcelo Tosatti	prompt "Disable host haltpoll when loading haltpoll driver"
816a1c4423bSMarcelo Tosatti	help
817a1c4423bSMarcelo Tosatti	  If virtualized under KVM, disable host haltpoll.
818a1c4423bSMarcelo Tosatti
8197733607fSMaran Wilsonconfig PVH
8207733607fSMaran Wilson	bool "Support for running PVH guests"
821a7f7f624SMasahiro Yamada	help
8227733607fSMaran Wilson	  This option enables the PVH entry point for guest virtual machines
8237733607fSMaran Wilson	  as specified in the x86/HVM direct boot ABI.
8247733607fSMaran Wilson
8256276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING
8266276a074SBorislav Petkov	bool "Paravirtual steal time accounting"
8276276a074SBorislav Petkov	depends on PARAVIRT
828a7f7f624SMasahiro Yamada	help
8296276a074SBorislav Petkov	  Select this option to enable fine granularity task steal time
8306276a074SBorislav Petkov	  accounting. Time spent executing other tasks in parallel with
8316276a074SBorislav Petkov	  the current vCPU is discounted from the vCPU power. To account for
8326276a074SBorislav Petkov	  that, there can be a small performance impact.
8336276a074SBorislav Petkov
8346276a074SBorislav Petkov	  If in doubt, say N here.
8356276a074SBorislav Petkov
8367af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK
8377af192c9SGerd Hoffmann	bool
8387af192c9SGerd Hoffmann
8394a362601SJan Kiszkaconfig JAILHOUSE_GUEST
8404a362601SJan Kiszka	bool "Jailhouse non-root cell support"
841abde587bSArnd Bergmann	depends on X86_64 && PCI
84287e65d05SJan Kiszka	select X86_PM_TIMER
843a7f7f624SMasahiro Yamada	help
8444a362601SJan Kiszka	  This option allows to run Linux as guest in a Jailhouse non-root
8454a362601SJan Kiszka	  cell. You can leave this option disabled if you only want to start
8464a362601SJan Kiszka	  Jailhouse and run Linux afterwards in the root cell.
8474a362601SJan Kiszka
848ec7972c9SZhao Yakuiconfig ACRN_GUEST
849ec7972c9SZhao Yakui	bool "ACRN Guest support"
850ec7972c9SZhao Yakui	depends on X86_64
851498ad393SZhao Yakui	select X86_HV_CALLBACK_VECTOR
852ec7972c9SZhao Yakui	help
853ec7972c9SZhao Yakui	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
854ec7972c9SZhao Yakui	  a flexible, lightweight reference open-source hypervisor, built with
855ec7972c9SZhao Yakui	  real-time and safety-criticality in mind. It is built for embedded
856ec7972c9SZhao Yakui	  IOT with small footprint and real-time features. More details can be
857ec7972c9SZhao Yakui	  found in https://projectacrn.org/.
858ec7972c9SZhao Yakui
8596276a074SBorislav Petkovendif #HYPERVISOR_GUEST
86097349135SJeremy Fitzhardinge
861506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu"
862506f1d07SSam Ravnborg
863506f1d07SSam Ravnborgconfig HPET_TIMER
8643c2362e6SHarvey Harrison	def_bool X86_64
865506f1d07SSam Ravnborg	prompt "HPET Timer Support" if X86_32
866a7f7f624SMasahiro Yamada	help
867506f1d07SSam Ravnborg	  Use the IA-PC HPET (High Precision Event Timer) to manage
868506f1d07SSam Ravnborg	  time in preference to the PIT and RTC, if a HPET is
869506f1d07SSam Ravnborg	  present.
870506f1d07SSam Ravnborg	  HPET is the next generation timer replacing legacy 8254s.
871506f1d07SSam Ravnborg	  The HPET provides a stable time base on SMP
872506f1d07SSam Ravnborg	  systems, unlike the TSC, but it is more expensive to access,
8734e7f9df2SMichael S. Tsirkin	  as it is off-chip.  The interface used is documented
8744e7f9df2SMichael S. Tsirkin	  in the HPET spec, revision 1.
875506f1d07SSam Ravnborg
876506f1d07SSam Ravnborg	  You can safely choose Y here.  However, HPET will only be
877506f1d07SSam Ravnborg	  activated if the platform and the BIOS support this feature.
878506f1d07SSam Ravnborg	  Otherwise the 8254 will be used for timing services.
879506f1d07SSam Ravnborg
880506f1d07SSam Ravnborg	  Choose N to continue using the legacy 8254 timer.
881506f1d07SSam Ravnborg
882506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC
8833c2362e6SHarvey Harrison	def_bool y
8849d8af78bSBernhard Walle	depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
885506f1d07SSam Ravnborg
886bb24c471SJacob Panconfig APB_TIMER
887933b9463SAlan Cox	def_bool y if X86_INTEL_MID
888933b9463SAlan Cox	prompt "Intel MID APB Timer Support" if X86_INTEL_MID
88906c3df49SJamie Iles	select DW_APB_TIMER
890a0c3832aSAlan Cox	depends on X86_INTEL_MID && SFI
891bb24c471SJacob Pan	help
892bb24c471SJacob Pan	 APB timer is the replacement for 8254, HPET on X86 MID platforms.
893bb24c471SJacob Pan	 The APBT provides a stable time base on SMP
894bb24c471SJacob Pan	 systems, unlike the TSC, but it is more expensive to access,
895bb24c471SJacob Pan	 as it is off-chip. APB timers are always running regardless of CPU
896bb24c471SJacob Pan	 C states, they are used as per CPU clockevent device when possible.
897bb24c471SJacob Pan
8986a108a14SDavid Rientjes# Mark as expert because too many people got it wrong.
899506f1d07SSam Ravnborg# The code disables itself when not needed.
9007ae9392cSThomas Petazzoniconfig DMI
9017ae9392cSThomas Petazzoni	default y
902cf074402SArd Biesheuvel	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
9036a108a14SDavid Rientjes	bool "Enable DMI scanning" if EXPERT
904a7f7f624SMasahiro Yamada	help
9057ae9392cSThomas Petazzoni	  Enabled scanning of DMI to identify machine quirks. Say Y
9067ae9392cSThomas Petazzoni	  here unless you have verified that your setup is not
9077ae9392cSThomas Petazzoni	  affected by entries in the DMI blacklist. Required by PNP
9087ae9392cSThomas Petazzoni	  BIOS code.
9097ae9392cSThomas Petazzoni
910506f1d07SSam Ravnborgconfig GART_IOMMU
91138901f1cSAndi Kleen	bool "Old AMD GART IOMMU support"
912a4ce5a48SChristoph Hellwig	select IOMMU_HELPER
913506f1d07SSam Ravnborg	select SWIOTLB
91423ac4ae8SAndreas Herrmann	depends on X86_64 && PCI && AMD_NB
915a7f7f624SMasahiro Yamada	help
916ced3c42cSIngo Molnar	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
917ced3c42cSIngo Molnar	  GART based hardware IOMMUs.
918ced3c42cSIngo Molnar
919ced3c42cSIngo Molnar	  The GART supports full DMA access for devices with 32-bit access
920ced3c42cSIngo Molnar	  limitations, on systems with more than 3 GB. This is usually needed
921ced3c42cSIngo Molnar	  for USB, sound, many IDE/SATA chipsets and some other devices.
922ced3c42cSIngo Molnar
923ced3c42cSIngo Molnar	  Newer systems typically have a modern AMD IOMMU, supported via
924ced3c42cSIngo Molnar	  the CONFIG_AMD_IOMMU=y config option.
925ced3c42cSIngo Molnar
926ced3c42cSIngo Molnar	  In normal configurations this driver is only active when needed:
927ced3c42cSIngo Molnar	  there's more than 3 GB of memory and the system contains a
928ced3c42cSIngo Molnar	  32-bit limited device.
929ced3c42cSIngo Molnar
930ced3c42cSIngo Molnar	  If unsure, say Y.
931506f1d07SSam Ravnborg
9321184dc2fSMike Travisconfig MAXSMP
933ddb0c5a6SSamuel Thibault	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
9346ea30386SKees Cook	depends on X86_64 && SMP && DEBUG_KERNEL
93536f5101aSMike Travis	select CPUMASK_OFFSTACK
936a7f7f624SMasahiro Yamada	help
937ddb0c5a6SSamuel Thibault	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
9381184dc2fSMike Travis	  If unsure, say N.
939506f1d07SSam Ravnborg
940aec6487eSIngo Molnar#
941aec6487eSIngo Molnar# The maximum number of CPUs supported:
942aec6487eSIngo Molnar#
943aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
944aec6487eSIngo Molnar# and which can be configured interactively in the
945aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
946aec6487eSIngo Molnar#
947aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on
948aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel.
949aec6487eSIngo Molnar#
950aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable
951aec6487eSIngo Molnar#   interactive configuration. )
952aec6487eSIngo Molnar#
953a0d0bb4dSRandy Dunlap
954aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN
955a0d0bb4dSRandy Dunlap	int
956aec6487eSIngo Molnar	default NR_CPUS_RANGE_END if MAXSMP
957a0d0bb4dSRandy Dunlap	default    1 if !SMP
958a0d0bb4dSRandy Dunlap	default    2
959a0d0bb4dSRandy Dunlap
960aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END
961a0d0bb4dSRandy Dunlap	int
962a0d0bb4dSRandy Dunlap	depends on X86_32
963aec6487eSIngo Molnar	default   64 if  SMP &&  X86_BIGSMP
964aec6487eSIngo Molnar	default    8 if  SMP && !X86_BIGSMP
965a0d0bb4dSRandy Dunlap	default    1 if !SMP
966a0d0bb4dSRandy Dunlap
967aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END
968a0d0bb4dSRandy Dunlap	int
969a0d0bb4dSRandy Dunlap	depends on X86_64
9701edae1aeSScott Wood	default 8192 if  SMP && CPUMASK_OFFSTACK
9711edae1aeSScott Wood	default  512 if  SMP && !CPUMASK_OFFSTACK
972a0d0bb4dSRandy Dunlap	default    1 if !SMP
973aec6487eSIngo Molnar
974aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT
975aec6487eSIngo Molnar	int
976aec6487eSIngo Molnar	depends on X86_32
977aec6487eSIngo Molnar	default   32 if  X86_BIGSMP
978aec6487eSIngo Molnar	default    8 if  SMP
979aec6487eSIngo Molnar	default    1 if !SMP
980aec6487eSIngo Molnar
981aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT
982aec6487eSIngo Molnar	int
983aec6487eSIngo Molnar	depends on X86_64
984a0d0bb4dSRandy Dunlap	default 8192 if  MAXSMP
985a0d0bb4dSRandy Dunlap	default   64 if  SMP
986aec6487eSIngo Molnar	default    1 if !SMP
987a0d0bb4dSRandy Dunlap
988506f1d07SSam Ravnborgconfig NR_CPUS
98936f5101aSMike Travis	int "Maximum number of CPUs" if SMP && !MAXSMP
990aec6487eSIngo Molnar	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
991aec6487eSIngo Molnar	default NR_CPUS_DEFAULT
992a7f7f624SMasahiro Yamada	help
993506f1d07SSam Ravnborg	  This allows you to specify the maximum number of CPUs which this
994bb61ccc7SJosh Boyer	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
995cad14bb9SKirill A. Shutemov	  supported value is 8192, otherwise the maximum value is 512.  The
996506f1d07SSam Ravnborg	  minimum value which makes sense is 2.
997506f1d07SSam Ravnborg
998aec6487eSIngo Molnar	  This is purely to save memory: each supported CPU adds about 8KB
999aec6487eSIngo Molnar	  to the kernel image.
1000506f1d07SSam Ravnborg
1001506f1d07SSam Ravnborgconfig SCHED_SMT
1002dbe73364SThomas Gleixner	def_bool y if SMP
1003506f1d07SSam Ravnborg
1004506f1d07SSam Ravnborgconfig SCHED_MC
10053c2362e6SHarvey Harrison	def_bool y
10063c2362e6SHarvey Harrison	prompt "Multi-core scheduler support"
1007c8e56d20SBorislav Petkov	depends on SMP
1008a7f7f624SMasahiro Yamada	help
1009506f1d07SSam Ravnborg	  Multi-core scheduler support improves the CPU scheduler's decision
1010506f1d07SSam Ravnborg	  making when dealing with multi-core CPU chips at a cost of slightly
1011506f1d07SSam Ravnborg	  increased overhead in some places. If unsure say N here.
1012506f1d07SSam Ravnborg
1013de966cf4STim Chenconfig SCHED_MC_PRIO
1014de966cf4STim Chen	bool "CPU core priorities scheduler support"
10150a21fc12SIngo Molnar	depends on SCHED_MC && CPU_SUP_INTEL
10160a21fc12SIngo Molnar	select X86_INTEL_PSTATE
10170a21fc12SIngo Molnar	select CPU_FREQ
1018de966cf4STim Chen	default y
1019a7f7f624SMasahiro Yamada	help
1020de966cf4STim Chen	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1021de966cf4STim Chen	  core ordering determined at manufacturing time, which allows
1022de966cf4STim Chen	  certain cores to reach higher turbo frequencies (when running
1023de966cf4STim Chen	  single threaded workloads) than others.
1024de966cf4STim Chen
1025de966cf4STim Chen	  Enabling this kernel feature teaches the scheduler about
1026de966cf4STim Chen	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1027de966cf4STim Chen	  scheduler's CPU selection logic accordingly, so that higher
1028de966cf4STim Chen	  overall system performance can be achieved.
1029de966cf4STim Chen
1030de966cf4STim Chen	  This feature will have no effect on CPUs without this feature.
1031de966cf4STim Chen
1032de966cf4STim Chen	  If unsure say Y here.
10335e76b2abSTim Chen
103430b8b006SThomas Gleixnerconfig UP_LATE_INIT
103530b8b006SThomas Gleixner	def_bool y
1036ba360f88SThomas Gleixner	depends on !SMP && X86_LOCAL_APIC
103730b8b006SThomas Gleixner
1038506f1d07SSam Ravnborgconfig X86_UP_APIC
103950849eefSJan Beulich	bool "Local APIC support on uniprocessors" if !PCI_MSI
104050849eefSJan Beulich	default PCI_MSI
104138a1dfdaSBryan O'Donoghue	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1042a7f7f624SMasahiro Yamada	help
1043506f1d07SSam Ravnborg	  A local APIC (Advanced Programmable Interrupt Controller) is an
1044506f1d07SSam Ravnborg	  integrated interrupt controller in the CPU. If you have a single-CPU
1045506f1d07SSam Ravnborg	  system which has a processor with a local APIC, you can say Y here to
1046506f1d07SSam Ravnborg	  enable and use it. If you say Y here even though your machine doesn't
1047506f1d07SSam Ravnborg	  have a local APIC, then the kernel will still run with no slowdown at
1048506f1d07SSam Ravnborg	  all. The local APIC supports CPU-generated self-interrupts (timer,
1049506f1d07SSam Ravnborg	  performance counters), and the NMI watchdog which detects hard
1050506f1d07SSam Ravnborg	  lockups.
1051506f1d07SSam Ravnborg
1052506f1d07SSam Ravnborgconfig X86_UP_IOAPIC
1053506f1d07SSam Ravnborg	bool "IO-APIC support on uniprocessors"
1054506f1d07SSam Ravnborg	depends on X86_UP_APIC
1055a7f7f624SMasahiro Yamada	help
1056506f1d07SSam Ravnborg	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1057506f1d07SSam Ravnborg	  SMP-capable replacement for PC-style interrupt controllers. Most
1058506f1d07SSam Ravnborg	  SMP systems and many recent uniprocessor systems have one.
1059506f1d07SSam Ravnborg
1060506f1d07SSam Ravnborg	  If you have a single-CPU system with an IO-APIC, you can say Y here
1061506f1d07SSam Ravnborg	  to use it. If you say Y here even though your machine doesn't have
1062506f1d07SSam Ravnborg	  an IO-APIC, then the kernel will still run with no slowdown at all.
1063506f1d07SSam Ravnborg
1064506f1d07SSam Ravnborgconfig X86_LOCAL_APIC
10653c2362e6SHarvey Harrison	def_bool y
10660dbc6078SThomas Petazzoni	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1067b5dc8e6cSJiang Liu	select IRQ_DOMAIN_HIERARCHY
106852f518a3SJiang Liu	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1069506f1d07SSam Ravnborg
1070506f1d07SSam Ravnborgconfig X86_IO_APIC
1071b1da1e71SJan Beulich	def_bool y
1072b1da1e71SJan Beulich	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1073506f1d07SSam Ravnborg
107441b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS
107541b9eb26SStefan Assmann	bool "Reroute for broken boot IRQs"
107641b9eb26SStefan Assmann	depends on X86_IO_APIC
1077a7f7f624SMasahiro Yamada	help
107841b9eb26SStefan Assmann	  This option enables a workaround that fixes a source of
107941b9eb26SStefan Assmann	  spurious interrupts. This is recommended when threaded
108041b9eb26SStefan Assmann	  interrupt handling is used on systems where the generation of
108141b9eb26SStefan Assmann	  superfluous "boot interrupts" cannot be disabled.
108241b9eb26SStefan Assmann
108341b9eb26SStefan Assmann	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
108441b9eb26SStefan Assmann	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
108541b9eb26SStefan Assmann	  kernel does during interrupt handling). On chipsets where this
108641b9eb26SStefan Assmann	  boot IRQ generation cannot be disabled, this workaround keeps
108741b9eb26SStefan Assmann	  the original IRQ line masked so that only the equivalent "boot
108841b9eb26SStefan Assmann	  IRQ" is delivered to the CPUs. The workaround also tells the
108941b9eb26SStefan Assmann	  kernel to set up the IRQ handler on the boot IRQ line. In this
109041b9eb26SStefan Assmann	  way only one interrupt is delivered to the kernel. Otherwise
109141b9eb26SStefan Assmann	  the spurious second interrupt may cause the kernel to bring
109241b9eb26SStefan Assmann	  down (vital) interrupt lines.
109341b9eb26SStefan Assmann
109441b9eb26SStefan Assmann	  Only affects "broken" chipsets. Interrupt sharing may be
109541b9eb26SStefan Assmann	  increased on these systems.
109641b9eb26SStefan Assmann
1097506f1d07SSam Ravnborgconfig X86_MCE
1098bab9bc65SAndi Kleen	bool "Machine Check / overheating reporting"
1099648ed940SChen, Gong	select GENERIC_ALLOCATOR
1100e57dbaf7SBorislav Petkov	default y
1101a7f7f624SMasahiro Yamada	help
1102bab9bc65SAndi Kleen	  Machine Check support allows the processor to notify the
1103bab9bc65SAndi Kleen	  kernel if it detects a problem (e.g. overheating, data corruption).
1104506f1d07SSam Ravnborg	  The action the kernel takes depends on the severity of the problem,
1105bab9bc65SAndi Kleen	  ranging from warning messages to halting the machine.
11064efc0670SAndi Kleen
11075de97c9fSTony Luckconfig X86_MCELOG_LEGACY
11085de97c9fSTony Luck	bool "Support for deprecated /dev/mcelog character device"
11095de97c9fSTony Luck	depends on X86_MCE
1110a7f7f624SMasahiro Yamada	help
11115de97c9fSTony Luck	  Enable support for /dev/mcelog which is needed by the old mcelog
11125de97c9fSTony Luck	  userspace logging daemon. Consider switching to the new generation
11135de97c9fSTony Luck	  rasdaemon solution.
11145de97c9fSTony Luck
1115506f1d07SSam Ravnborgconfig X86_MCE_INTEL
11163c2362e6SHarvey Harrison	def_bool y
11173c2362e6SHarvey Harrison	prompt "Intel MCE features"
1118c1ebf835SAndi Kleen	depends on X86_MCE && X86_LOCAL_APIC
1119a7f7f624SMasahiro Yamada	help
1120506f1d07SSam Ravnborg	   Additional support for intel specific MCE features such as
1121506f1d07SSam Ravnborg	   the thermal monitor.
1122506f1d07SSam Ravnborg
1123506f1d07SSam Ravnborgconfig X86_MCE_AMD
11243c2362e6SHarvey Harrison	def_bool y
11253c2362e6SHarvey Harrison	prompt "AMD MCE features"
1126f5382de9SYazen Ghannam	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1127a7f7f624SMasahiro Yamada	help
1128506f1d07SSam Ravnborg	   Additional support for AMD specific MCE features such as
1129506f1d07SSam Ravnborg	   the DRAM Error Threshold.
1130506f1d07SSam Ravnborg
11314efc0670SAndi Kleenconfig X86_ANCIENT_MCE
11326fc108a0SJan Beulich	bool "Support for old Pentium 5 / WinChip machine checks"
1133c31d9633SAndi Kleen	depends on X86_32 && X86_MCE
1134a7f7f624SMasahiro Yamada	help
11354efc0670SAndi Kleen	  Include support for machine check handling on old Pentium 5 or WinChip
11365065a706SMasanari Iida	  systems. These typically need to be enabled explicitly on the command
11374efc0670SAndi Kleen	  line.
11384efc0670SAndi Kleen
1139b2762686SAndi Kleenconfig X86_MCE_THRESHOLD
1140b2762686SAndi Kleen	depends on X86_MCE_AMD || X86_MCE_INTEL
11416fc108a0SJan Beulich	def_bool y
1142b2762686SAndi Kleen
1143ea149b36SAndi Kleenconfig X86_MCE_INJECT
1144bc8e80d5SBorislav Petkov	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1145ea149b36SAndi Kleen	tristate "Machine check injector support"
1146a7f7f624SMasahiro Yamada	help
1147ea149b36SAndi Kleen	  Provide support for injecting machine checks for testing purposes.
1148ea149b36SAndi Kleen	  If you don't know what a machine check is and you don't do kernel
1149ea149b36SAndi Kleen	  QA it is safe to say n.
1150ea149b36SAndi Kleen
11514efc0670SAndi Kleenconfig X86_THERMAL_VECTOR
11524efc0670SAndi Kleen	def_bool y
11535bb38adcSAndi Kleen	depends on X86_MCE_INTEL
11544efc0670SAndi Kleen
115507dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig"
1156e633c65aSKan Liang
11575aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86
11581e642812SIngo Molnar	bool "Legacy VM86 support"
1159506f1d07SSam Ravnborg	depends on X86_32
1160a7f7f624SMasahiro Yamada	help
11615aef51c3SAndy Lutomirski	  This option allows user programs to put the CPU into V8086
11625aef51c3SAndy Lutomirski	  mode, which is an 80286-era approximation of 16-bit real mode.
11635aef51c3SAndy Lutomirski
11645aef51c3SAndy Lutomirski	  Some very old versions of X and/or vbetool require this option
11655aef51c3SAndy Lutomirski	  for user mode setting.  Similarly, DOSEMU will use it if
11665aef51c3SAndy Lutomirski	  available to accelerate real mode DOS programs.  However, any
11675aef51c3SAndy Lutomirski	  recent version of DOSEMU, X, or vbetool should be fully
11685aef51c3SAndy Lutomirski	  functional even without kernel VM86 support, as they will all
11691e642812SIngo Molnar	  fall back to software emulation. Nevertheless, if you are using
11701e642812SIngo Molnar	  a 16-bit DOS program where 16-bit performance matters, vm86
11711e642812SIngo Molnar	  mode might be faster than emulation and you might want to
11721e642812SIngo Molnar	  enable this option.
11735aef51c3SAndy Lutomirski
11741e642812SIngo Molnar	  Note that any app that works on a 64-bit kernel is unlikely to
11751e642812SIngo Molnar	  need this option, as 64-bit kernels don't, and can't, support
11761e642812SIngo Molnar	  V8086 mode. This option is also unrelated to 16-bit protected
11771e642812SIngo Molnar	  mode and is not needed to run most 16-bit programs under Wine.
11785aef51c3SAndy Lutomirski
11791e642812SIngo Molnar	  Enabling this option increases the complexity of the kernel
11801e642812SIngo Molnar	  and slows down exception handling a tiny bit.
11815aef51c3SAndy Lutomirski
11821e642812SIngo Molnar	  If unsure, say N here.
11835aef51c3SAndy Lutomirski
11845aef51c3SAndy Lutomirskiconfig VM86
11855aef51c3SAndy Lutomirski	bool
11865aef51c3SAndy Lutomirski	default X86_LEGACY_VM86
118734273f41SH. Peter Anvin
118834273f41SH. Peter Anvinconfig X86_16BIT
118934273f41SH. Peter Anvin	bool "Enable support for 16-bit segments" if EXPERT
119034273f41SH. Peter Anvin	default y
1191a5b9e5a2SAndy Lutomirski	depends on MODIFY_LDT_SYSCALL
1192a7f7f624SMasahiro Yamada	help
119334273f41SH. Peter Anvin	  This option is required by programs like Wine to run 16-bit
119434273f41SH. Peter Anvin	  protected mode legacy code on x86 processors.  Disabling
119534273f41SH. Peter Anvin	  this option saves about 300 bytes on i386, or around 6K text
119634273f41SH. Peter Anvin	  plus 16K runtime memory on x86-64,
119734273f41SH. Peter Anvin
119834273f41SH. Peter Anvinconfig X86_ESPFIX32
119934273f41SH. Peter Anvin	def_bool y
120034273f41SH. Peter Anvin	depends on X86_16BIT && X86_32
1201506f1d07SSam Ravnborg
1202197725deSH. Peter Anvinconfig X86_ESPFIX64
1203197725deSH. Peter Anvin	def_bool y
120434273f41SH. Peter Anvin	depends on X86_16BIT && X86_64
1205506f1d07SSam Ravnborg
12061ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION
12071ad83c85SAndy Lutomirski	bool "Enable vsyscall emulation" if EXPERT
12081ad83c85SAndy Lutomirski	default y
12091ad83c85SAndy Lutomirski	depends on X86_64
1210a7f7f624SMasahiro Yamada	help
12111ad83c85SAndy Lutomirski	 This enables emulation of the legacy vsyscall page.  Disabling
12121ad83c85SAndy Lutomirski	 it is roughly equivalent to booting with vsyscall=none, except
12131ad83c85SAndy Lutomirski	 that it will also disable the helpful warning if a program
12141ad83c85SAndy Lutomirski	 tries to use a vsyscall.  With this option set to N, offending
12151ad83c85SAndy Lutomirski	 programs will just segfault, citing addresses of the form
12161ad83c85SAndy Lutomirski	 0xffffffffff600?00.
12171ad83c85SAndy Lutomirski
12181ad83c85SAndy Lutomirski	 This option is required by many programs built before 2013, and
12191ad83c85SAndy Lutomirski	 care should be used even with newer programs if set to N.
12201ad83c85SAndy Lutomirski
12211ad83c85SAndy Lutomirski	 Disabling this option saves about 7K of kernel size and
12221ad83c85SAndy Lutomirski	 possibly 4K of additional runtime pagetable memory.
12231ad83c85SAndy Lutomirski
1224111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM
1225111e7b15SThomas Gleixner	bool "IOPERM and IOPL Emulation"
1226a24ca997SThomas Gleixner	default y
1227a7f7f624SMasahiro Yamada	help
1228111e7b15SThomas Gleixner	  This enables the ioperm() and iopl() syscalls which are necessary
1229111e7b15SThomas Gleixner	  for legacy applications.
1230111e7b15SThomas Gleixner
1231c8137aceSThomas Gleixner	  Legacy IOPL support is an overbroad mechanism which allows user
1232c8137aceSThomas Gleixner	  space aside of accessing all 65536 I/O ports also to disable
1233c8137aceSThomas Gleixner	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1234c8137aceSThomas Gleixner	  capabilities and permission from potentially active security
1235c8137aceSThomas Gleixner	  modules.
1236c8137aceSThomas Gleixner
1237c8137aceSThomas Gleixner	  The emulation restricts the functionality of the syscall to
1238c8137aceSThomas Gleixner	  only allowing the full range I/O port access, but prevents the
1239a24ca997SThomas Gleixner	  ability to disable interrupts from user space which would be
1240a24ca997SThomas Gleixner	  granted if the hardware IOPL mechanism would be used.
1241c8137aceSThomas Gleixner
1242506f1d07SSam Ravnborgconfig TOSHIBA
1243506f1d07SSam Ravnborg	tristate "Toshiba Laptop support"
1244506f1d07SSam Ravnborg	depends on X86_32
1245a7f7f624SMasahiro Yamada	help
1246506f1d07SSam Ravnborg	  This adds a driver to safely access the System Management Mode of
1247506f1d07SSam Ravnborg	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1248506f1d07SSam Ravnborg	  not work on models with a Phoenix BIOS. The System Management Mode
1249506f1d07SSam Ravnborg	  is used to set the BIOS and power saving options on Toshiba portables.
1250506f1d07SSam Ravnborg
1251506f1d07SSam Ravnborg	  For information on utilities to make use of this driver see the
1252506f1d07SSam Ravnborg	  Toshiba Linux utilities web site at:
1253506f1d07SSam Ravnborg	  <http://www.buzzard.org.uk/toshiba/>.
1254506f1d07SSam Ravnborg
1255506f1d07SSam Ravnborg	  Say Y if you intend to run this kernel on a Toshiba portable.
1256506f1d07SSam Ravnborg	  Say N otherwise.
1257506f1d07SSam Ravnborg
1258506f1d07SSam Ravnborgconfig I8K
1259039ae585SPali Rohár	tristate "Dell i8k legacy laptop support"
1260949a9d70SJean Delvare	select HWMON
1261039ae585SPali Rohár	select SENSORS_DELL_SMM
1262a7f7f624SMasahiro Yamada	help
1263039ae585SPali Rohár	  This option enables legacy /proc/i8k userspace interface in hwmon
1264039ae585SPali Rohár	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1265039ae585SPali Rohár	  temperature and allows controlling fan speeds of Dell laptops via
1266039ae585SPali Rohár	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1267039ae585SPali Rohár	  it reports also power and hotkey status. For fan speed control is
1268039ae585SPali Rohár	  needed userspace package i8kutils.
1269506f1d07SSam Ravnborg
1270039ae585SPali Rohár	  Say Y if you intend to run this kernel on old Dell laptops or want to
1271039ae585SPali Rohár	  use userspace package i8kutils.
1272506f1d07SSam Ravnborg	  Say N otherwise.
1273506f1d07SSam Ravnborg
1274506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS
12759ba16087SJan Beulich	bool "Enable X86 board specific fixups for reboot"
12769ba16087SJan Beulich	depends on X86_32
1277a7f7f624SMasahiro Yamada	help
1278506f1d07SSam Ravnborg	  This enables chipset and/or board specific fixups to be done
1279506f1d07SSam Ravnborg	  in order to get reboot to work correctly. This is only needed on
1280506f1d07SSam Ravnborg	  some combinations of hardware and BIOS. The symptom, for which
1281506f1d07SSam Ravnborg	  this config is intended, is when reboot ends with a stalled/hung
1282506f1d07SSam Ravnborg	  system.
1283506f1d07SSam Ravnborg
1284506f1d07SSam Ravnborg	  Currently, the only fixup is for the Geode machines using
12855e3a77e9SFlorian Fainelli	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1286506f1d07SSam Ravnborg
1287506f1d07SSam Ravnborg	  Say Y if you want to enable the fixup. Currently, it's safe to
1288506f1d07SSam Ravnborg	  enable this option even if you don't need it.
1289506f1d07SSam Ravnborg	  Say N otherwise.
1290506f1d07SSam Ravnborg
1291506f1d07SSam Ravnborgconfig MICROCODE
12929a2bc335SBorislav Petkov	bool "CPU microcode loading support"
12939a2bc335SBorislav Petkov	default y
129480030e3dSBorislav Petkov	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1295506f1d07SSam Ravnborg	select FW_LOADER
1296a7f7f624SMasahiro Yamada	help
1297506f1d07SSam Ravnborg	  If you say Y here, you will be able to update the microcode on
12985f9c01aaSBorislav Petkov	  Intel and AMD processors. The Intel support is for the IA32 family,
12995f9c01aaSBorislav Petkov	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
13005f9c01aaSBorislav Petkov	  AMD support is for families 0x10 and later. You will obviously need
13015f9c01aaSBorislav Petkov	  the actual microcode binary data itself which is not shipped with
13025f9c01aaSBorislav Petkov	  the Linux kernel.
1303506f1d07SSam Ravnborg
13045f9c01aaSBorislav Petkov	  The preferred method to load microcode from a detached initrd is described
1305cb1aaebeSMauro Carvalho Chehab	  in Documentation/x86/microcode.rst. For that you need to enable
13065f9c01aaSBorislav Petkov	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
13075f9c01aaSBorislav Petkov	  initrd for microcode blobs.
1308506f1d07SSam Ravnborg
1309c508c46eSBenjamin Gilbert	  In addition, you can build the microcode into the kernel. For that you
1310c508c46eSBenjamin Gilbert	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1311c508c46eSBenjamin Gilbert	  config option.
1312506f1d07SSam Ravnborg
13138d86f390SPeter Orubaconfig MICROCODE_INTEL
1314e43f6e67SBorislav Petkov	bool "Intel microcode loading support"
13158d86f390SPeter Oruba	depends on MICROCODE
13168d86f390SPeter Oruba	default MICROCODE
13178d86f390SPeter Oruba	select FW_LOADER
1318a7f7f624SMasahiro Yamada	help
13198d86f390SPeter Oruba	  This options enables microcode patch loading support for Intel
13208d86f390SPeter Oruba	  processors.
13218d86f390SPeter Oruba
1322b8989db9SAlan	  For the current Intel microcode data package go to
1323b8989db9SAlan	  <https://downloadcenter.intel.com> and search for
1324b8989db9SAlan	  'Linux Processor Microcode Data File'.
13258d86f390SPeter Oruba
132680cc9f10SPeter Orubaconfig MICROCODE_AMD
1327e43f6e67SBorislav Petkov	bool "AMD microcode loading support"
132880cc9f10SPeter Oruba	depends on MICROCODE
132980cc9f10SPeter Oruba	select FW_LOADER
1330a7f7f624SMasahiro Yamada	help
133180cc9f10SPeter Oruba	  If you select this option, microcode patch loading support for AMD
133280cc9f10SPeter Oruba	  processors will be enabled.
133380cc9f10SPeter Oruba
1334506f1d07SSam Ravnborgconfig MICROCODE_OLD_INTERFACE
1335c02f48e0SBorislav Petkov	bool "Ancient loading interface (DEPRECATED)"
1336c02f48e0SBorislav Petkov	default n
1337506f1d07SSam Ravnborg	depends on MICROCODE
1338a7f7f624SMasahiro Yamada	help
1339c02f48e0SBorislav Petkov	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1340c02f48e0SBorislav Petkov	  which was used by userspace tools like iucode_tool and microcode.ctl.
1341c02f48e0SBorislav Petkov	  It is inadequate because it runs too late to be able to properly
1342c02f48e0SBorislav Petkov	  load microcode on a machine and it needs special tools. Instead, you
1343c02f48e0SBorislav Petkov	  should've switched to the early loading method with the initrd or
1344cb1aaebeSMauro Carvalho Chehab	  builtin microcode by now: Documentation/x86/microcode.rst
1345506f1d07SSam Ravnborg
1346506f1d07SSam Ravnborgconfig X86_MSR
1347506f1d07SSam Ravnborg	tristate "/dev/cpu/*/msr - Model-specific register support"
1348a7f7f624SMasahiro Yamada	help
1349506f1d07SSam Ravnborg	  This device gives privileged processes access to the x86
1350506f1d07SSam Ravnborg	  Model-Specific Registers (MSRs).  It is a character device with
1351506f1d07SSam Ravnborg	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1352506f1d07SSam Ravnborg	  MSR accesses are directed to a specific CPU on multi-processor
1353506f1d07SSam Ravnborg	  systems.
1354506f1d07SSam Ravnborg
1355506f1d07SSam Ravnborgconfig X86_CPUID
1356506f1d07SSam Ravnborg	tristate "/dev/cpu/*/cpuid - CPU information support"
1357a7f7f624SMasahiro Yamada	help
1358506f1d07SSam Ravnborg	  This device gives processes access to the x86 CPUID instruction to
1359506f1d07SSam Ravnborg	  be executed on a specific processor.  It is a character device
1360506f1d07SSam Ravnborg	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1361506f1d07SSam Ravnborg	  /dev/cpu/31/cpuid.
1362506f1d07SSam Ravnborg
1363506f1d07SSam Ravnborgchoice
1364506f1d07SSam Ravnborg	prompt "High Memory Support"
13656fc108a0SJan Beulich	default HIGHMEM4G
1366506f1d07SSam Ravnborg	depends on X86_32
1367506f1d07SSam Ravnborg
1368506f1d07SSam Ravnborgconfig NOHIGHMEM
1369506f1d07SSam Ravnborg	bool "off"
1370a7f7f624SMasahiro Yamada	help
1371506f1d07SSam Ravnborg	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1372506f1d07SSam Ravnborg	  However, the address space of 32-bit x86 processors is only 4
1373506f1d07SSam Ravnborg	  Gigabytes large. That means that, if you have a large amount of
1374506f1d07SSam Ravnborg	  physical memory, not all of it can be "permanently mapped" by the
1375506f1d07SSam Ravnborg	  kernel. The physical memory that's not permanently mapped is called
1376506f1d07SSam Ravnborg	  "high memory".
1377506f1d07SSam Ravnborg
1378506f1d07SSam Ravnborg	  If you are compiling a kernel which will never run on a machine with
1379506f1d07SSam Ravnborg	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1380506f1d07SSam Ravnborg	  choice and suitable for most users). This will result in a "3GB/1GB"
1381506f1d07SSam Ravnborg	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1382506f1d07SSam Ravnborg	  space and the remaining part of the 4GB virtual memory space is used
1383506f1d07SSam Ravnborg	  by the kernel to permanently map as much physical memory as
1384506f1d07SSam Ravnborg	  possible.
1385506f1d07SSam Ravnborg
1386506f1d07SSam Ravnborg	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1387506f1d07SSam Ravnborg	  answer "4GB" here.
1388506f1d07SSam Ravnborg
1389506f1d07SSam Ravnborg	  If more than 4 Gigabytes is used then answer "64GB" here. This
1390506f1d07SSam Ravnborg	  selection turns Intel PAE (Physical Address Extension) mode on.
1391506f1d07SSam Ravnborg	  PAE implements 3-level paging on IA32 processors. PAE is fully
1392506f1d07SSam Ravnborg	  supported by Linux, PAE mode is implemented on all recent Intel
1393506f1d07SSam Ravnborg	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1394506f1d07SSam Ravnborg	  then the kernel will not boot on CPUs that don't support PAE!
1395506f1d07SSam Ravnborg
1396506f1d07SSam Ravnborg	  The actual amount of total physical memory will either be
1397506f1d07SSam Ravnborg	  auto detected or can be forced by using a kernel command line option
1398506f1d07SSam Ravnborg	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1399506f1d07SSam Ravnborg	  your boot loader (lilo or loadlin) about how to pass options to the
1400506f1d07SSam Ravnborg	  kernel at boot time.)
1401506f1d07SSam Ravnborg
1402506f1d07SSam Ravnborg	  If unsure, say "off".
1403506f1d07SSam Ravnborg
1404506f1d07SSam Ravnborgconfig HIGHMEM4G
1405506f1d07SSam Ravnborg	bool "4GB"
1406a7f7f624SMasahiro Yamada	help
1407506f1d07SSam Ravnborg	  Select this if you have a 32-bit processor and between 1 and 4
1408506f1d07SSam Ravnborg	  gigabytes of physical RAM.
1409506f1d07SSam Ravnborg
1410506f1d07SSam Ravnborgconfig HIGHMEM64G
1411506f1d07SSam Ravnborg	bool "64GB"
141269b8d3fcSMatthew Whitehead	depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1413506f1d07SSam Ravnborg	select X86_PAE
1414a7f7f624SMasahiro Yamada	help
1415506f1d07SSam Ravnborg	  Select this if you have a 32-bit processor and more than 4
1416506f1d07SSam Ravnborg	  gigabytes of physical RAM.
1417506f1d07SSam Ravnborg
1418506f1d07SSam Ravnborgendchoice
1419506f1d07SSam Ravnborg
1420506f1d07SSam Ravnborgchoice
14216a108a14SDavid Rientjes	prompt "Memory split" if EXPERT
1422506f1d07SSam Ravnborg	default VMSPLIT_3G
1423506f1d07SSam Ravnborg	depends on X86_32
1424a7f7f624SMasahiro Yamada	help
1425506f1d07SSam Ravnborg	  Select the desired split between kernel and user memory.
1426506f1d07SSam Ravnborg
1427506f1d07SSam Ravnborg	  If the address range available to the kernel is less than the
1428506f1d07SSam Ravnborg	  physical memory installed, the remaining memory will be available
1429506f1d07SSam Ravnborg	  as "high memory". Accessing high memory is a little more costly
1430506f1d07SSam Ravnborg	  than low memory, as it needs to be mapped into the kernel first.
1431506f1d07SSam Ravnborg	  Note that increasing the kernel address space limits the range
1432506f1d07SSam Ravnborg	  available to user programs, making the address space there
1433506f1d07SSam Ravnborg	  tighter.  Selecting anything other than the default 3G/1G split
1434506f1d07SSam Ravnborg	  will also likely make your kernel incompatible with binary-only
1435506f1d07SSam Ravnborg	  kernel modules.
1436506f1d07SSam Ravnborg
1437506f1d07SSam Ravnborg	  If you are not absolutely sure what you are doing, leave this
1438506f1d07SSam Ravnborg	  option alone!
1439506f1d07SSam Ravnborg
1440506f1d07SSam Ravnborg	config VMSPLIT_3G
1441506f1d07SSam Ravnborg		bool "3G/1G user/kernel split"
1442506f1d07SSam Ravnborg	config VMSPLIT_3G_OPT
1443506f1d07SSam Ravnborg		depends on !X86_PAE
1444506f1d07SSam Ravnborg		bool "3G/1G user/kernel split (for full 1G low memory)"
1445506f1d07SSam Ravnborg	config VMSPLIT_2G
1446506f1d07SSam Ravnborg		bool "2G/2G user/kernel split"
1447506f1d07SSam Ravnborg	config VMSPLIT_2G_OPT
1448506f1d07SSam Ravnborg		depends on !X86_PAE
1449506f1d07SSam Ravnborg		bool "2G/2G user/kernel split (for full 2G low memory)"
1450506f1d07SSam Ravnborg	config VMSPLIT_1G
1451506f1d07SSam Ravnborg		bool "1G/3G user/kernel split"
1452506f1d07SSam Ravnborgendchoice
1453506f1d07SSam Ravnborg
1454506f1d07SSam Ravnborgconfig PAGE_OFFSET
1455506f1d07SSam Ravnborg	hex
1456506f1d07SSam Ravnborg	default 0xB0000000 if VMSPLIT_3G_OPT
1457506f1d07SSam Ravnborg	default 0x80000000 if VMSPLIT_2G
1458506f1d07SSam Ravnborg	default 0x78000000 if VMSPLIT_2G_OPT
1459506f1d07SSam Ravnborg	default 0x40000000 if VMSPLIT_1G
1460506f1d07SSam Ravnborg	default 0xC0000000
1461506f1d07SSam Ravnborg	depends on X86_32
1462506f1d07SSam Ravnborg
1463506f1d07SSam Ravnborgconfig HIGHMEM
14643c2362e6SHarvey Harrison	def_bool y
1465506f1d07SSam Ravnborg	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1466506f1d07SSam Ravnborg
1467506f1d07SSam Ravnborgconfig X86_PAE
14689ba16087SJan Beulich	bool "PAE (Physical Address Extension) Support"
1469506f1d07SSam Ravnborg	depends on X86_32 && !HIGHMEM4G
1470d4a451d5SChristoph Hellwig	select PHYS_ADDR_T_64BIT
14719d99c712SChristian Melki	select SWIOTLB
1472a7f7f624SMasahiro Yamada	help
1473506f1d07SSam Ravnborg	  PAE is required for NX support, and furthermore enables
1474506f1d07SSam Ravnborg	  larger swapspace support for non-overcommit purposes. It
1475506f1d07SSam Ravnborg	  has the cost of more pagetable lookup overhead, and also
1476506f1d07SSam Ravnborg	  consumes more pagetable space per process.
1477506f1d07SSam Ravnborg
147877ef56e4SKirill A. Shutemovconfig X86_5LEVEL
147977ef56e4SKirill A. Shutemov	bool "Enable 5-level page tables support"
148018ec1eafSKirill A. Shutemov	default y
1481eedb92abSKirill A. Shutemov	select DYNAMIC_MEMORY_LAYOUT
1482162434e7SKirill A. Shutemov	select SPARSEMEM_VMEMMAP
148377ef56e4SKirill A. Shutemov	depends on X86_64
1484a7f7f624SMasahiro Yamada	help
148577ef56e4SKirill A. Shutemov	  5-level paging enables access to larger address space:
148677ef56e4SKirill A. Shutemov	  upto 128 PiB of virtual address space and 4 PiB of
148777ef56e4SKirill A. Shutemov	  physical address space.
148877ef56e4SKirill A. Shutemov
148977ef56e4SKirill A. Shutemov	  It will be supported by future Intel CPUs.
149077ef56e4SKirill A. Shutemov
14916657fca0SKirill A. Shutemov	  A kernel with the option enabled can be booted on machines that
14926657fca0SKirill A. Shutemov	  support 4- or 5-level paging.
149377ef56e4SKirill A. Shutemov
1494cb1aaebeSMauro Carvalho Chehab	  See Documentation/x86/x86_64/5level-paging.rst for more
149577ef56e4SKirill A. Shutemov	  information.
149677ef56e4SKirill A. Shutemov
149777ef56e4SKirill A. Shutemov	  Say N if unsure.
149877ef56e4SKirill A. Shutemov
149910971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES
1500e5008abeSLuis R. Rodriguez	def_bool y
15012e1da13fSVlastimil Babka	depends on X86_64
1502a7f7f624SMasahiro Yamada	help
150310971ab2SIngo Molnar	  Certain kernel features effectively disable kernel
150410971ab2SIngo Molnar	  linear 1 GB mappings (even if the CPU otherwise
150510971ab2SIngo Molnar	  supports them), so don't confuse the user by printing
150610971ab2SIngo Molnar	  that we have them enabled.
15079e899816SNick Piggin
15085c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS
15095c280cf6SThomas Gleixner	bool "Enable statistic for Change Page Attribute"
15105c280cf6SThomas Gleixner	depends on DEBUG_FS
1511a7f7f624SMasahiro Yamada	help
1512b75baaf3SIngo Molnar	  Expose statistics about the Change Page Attribute mechanism, which
1513a943245aSColin Ian King	  helps to determine the effectiveness of preserving large and huge
15145c280cf6SThomas Gleixner	  page mappings when mapping protections are changed.
15155c280cf6SThomas Gleixner
15167744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT
15177744ccdbSTom Lendacky	bool "AMD Secure Memory Encryption (SME) support"
15187744ccdbSTom Lendacky	depends on X86_64 && CPU_SUP_AMD
151982fef0adSDavid Rientjes	select DMA_COHERENT_POOL
152094d49eb3SKirill A. Shutemov	select DYNAMIC_PHYSICAL_MASK
1521ce9084baSArd Biesheuvel	select ARCH_USE_MEMREMAP_PROT
15229087c375STom Lendacky	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1523a7f7f624SMasahiro Yamada	help
15247744ccdbSTom Lendacky	  Say yes to enable support for the encryption of system memory.
15257744ccdbSTom Lendacky	  This requires an AMD processor that supports Secure Memory
15267744ccdbSTom Lendacky	  Encryption (SME).
15277744ccdbSTom Lendacky
15287744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
15297744ccdbSTom Lendacky	bool "Activate AMD Secure Memory Encryption (SME) by default"
15307744ccdbSTom Lendacky	default y
15317744ccdbSTom Lendacky	depends on AMD_MEM_ENCRYPT
1532a7f7f624SMasahiro Yamada	help
15337744ccdbSTom Lendacky	  Say yes to have system memory encrypted by default if running on
15347744ccdbSTom Lendacky	  an AMD processor that supports Secure Memory Encryption (SME).
15357744ccdbSTom Lendacky
15367744ccdbSTom Lendacky	  If set to Y, then the encryption of system memory can be
15377744ccdbSTom Lendacky	  deactivated with the mem_encrypt=off command line option.
15387744ccdbSTom Lendacky
15397744ccdbSTom Lendacky	  If set to N, then the encryption of system memory can be
15407744ccdbSTom Lendacky	  activated with the mem_encrypt=on command line option.
15417744ccdbSTom Lendacky
1542506f1d07SSam Ravnborg# Common NUMA Features
1543506f1d07SSam Ravnborgconfig NUMA
1544e133f6eaSRandy Dunlap	bool "NUMA Memory Allocation and Scheduler Support"
1545506f1d07SSam Ravnborg	depends on SMP
1546b5660ba7SH. Peter Anvin	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1547b5660ba7SH. Peter Anvin	default y if X86_BIGSMP
1548a7f7f624SMasahiro Yamada	help
1549e133f6eaSRandy Dunlap	  Enable NUMA (Non-Uniform Memory Access) support.
1550fd51b2d7SKOSAKI Motohiro
1551506f1d07SSam Ravnborg	  The kernel will try to allocate memory used by a CPU on the
1552506f1d07SSam Ravnborg	  local memory controller of the CPU and add some more
1553506f1d07SSam Ravnborg	  NUMA awareness to the kernel.
1554506f1d07SSam Ravnborg
1555c280ea5eSIngo Molnar	  For 64-bit this is recommended if the system is Intel Core i7
1556fd51b2d7SKOSAKI Motohiro	  (or later), AMD Opteron, or EM64T NUMA.
1557fd51b2d7SKOSAKI Motohiro
1558b5660ba7SH. Peter Anvin	  For 32-bit this is only needed if you boot a 32-bit
15597cf6c945SDavid Rientjes	  kernel on a 64-bit NUMA platform.
1560fd51b2d7SKOSAKI Motohiro
1561fd51b2d7SKOSAKI Motohiro	  Otherwise, you should say N.
1562506f1d07SSam Ravnborg
1563eec1d4faSHans Rosenfeldconfig AMD_NUMA
15643c2362e6SHarvey Harrison	def_bool y
15653c2362e6SHarvey Harrison	prompt "Old style AMD Opteron NUMA detection"
15665da0ef9aSTejun Heo	depends on X86_64 && NUMA && PCI
1567a7f7f624SMasahiro Yamada	help
1568eec1d4faSHans Rosenfeld	  Enable AMD NUMA node topology detection.  You should say Y here if
1569eec1d4faSHans Rosenfeld	  you have a multi processor AMD system. This uses an old method to
1570eec1d4faSHans Rosenfeld	  read the NUMA configuration directly from the builtin Northbridge
1571eec1d4faSHans Rosenfeld	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1572eec1d4faSHans Rosenfeld	  which also takes priority if both are compiled in.
1573506f1d07SSam Ravnborg
1574506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA
15753c2362e6SHarvey Harrison	def_bool y
15763c2362e6SHarvey Harrison	prompt "ACPI NUMA detection"
1577506f1d07SSam Ravnborg	depends on X86_64 && NUMA && ACPI && PCI
1578506f1d07SSam Ravnborg	select ACPI_NUMA
1579a7f7f624SMasahiro Yamada	help
1580506f1d07SSam Ravnborg	  Enable ACPI SRAT based node topology detection.
1581506f1d07SSam Ravnborg
1582506f1d07SSam Ravnborgconfig NUMA_EMU
1583506f1d07SSam Ravnborg	bool "NUMA emulation"
15841b7e03efSTejun Heo	depends on NUMA
1585a7f7f624SMasahiro Yamada	help
1586506f1d07SSam Ravnborg	  Enable NUMA emulation. A flat machine will be split
1587506f1d07SSam Ravnborg	  into virtual nodes when booted with "numa=fake=N", where N is the
1588506f1d07SSam Ravnborg	  number of nodes. This is only useful for debugging.
1589506f1d07SSam Ravnborg
1590506f1d07SSam Ravnborgconfig NODES_SHIFT
1591d25e26b6SLinus Torvalds	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
159251591e31SDavid Rientjes	range 1 10
159351591e31SDavid Rientjes	default "10" if MAXSMP
1594506f1d07SSam Ravnborg	default "6" if X86_64
1595506f1d07SSam Ravnborg	default "3"
1596506f1d07SSam Ravnborg	depends on NEED_MULTIPLE_NODES
1597a7f7f624SMasahiro Yamada	help
15981184dc2fSMike Travis	  Specify the maximum number of NUMA Nodes available on the target
1599692105b8SMatt LaPlante	  system.  Increases memory reserved to accommodate various tables.
1600506f1d07SSam Ravnborg
1601506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE
1602506f1d07SSam Ravnborg	def_bool y
16033b16651fSTejun Heo	depends on X86_32 && !NUMA
1604506f1d07SSam Ravnborg
1605506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE
1606506f1d07SSam Ravnborg	def_bool y
16076ea30386SKees Cook	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1608506f1d07SSam Ravnborg	select SPARSEMEM_STATIC if X86_32
1609506f1d07SSam Ravnborg	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1610506f1d07SSam Ravnborg
16113b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT
16126ad57f7fSMike Rapoport	def_bool X86_64 || (NUMA && X86_32)
16133b16651fSTejun Heo
1614506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL
1615506f1d07SSam Ravnborg	def_bool y
1616b263295dSChristoph Lameter	depends on ARCH_SPARSEMEM_ENABLE
1617506f1d07SSam Ravnborg
1618506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE
1619a0842b70SToshi Kani	bool "Enable sysfs memory/probe interface"
16203120e25eSJan Beulich	depends on X86_64 && MEMORY_HOTPLUG
1621a0842b70SToshi Kani	help
1622a0842b70SToshi Kani	  This option enables a sysfs memory/probe interface for testing.
1623cb1aaebeSMauro Carvalho Chehab	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1624a0842b70SToshi Kani	  If you are unsure how to answer this question, answer N.
1625506f1d07SSam Ravnborg
16263b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT
16273b16651fSTejun Heo	def_bool y
16283b16651fSTejun Heo	depends on X86_64 && PROC_KCORE
16293b16651fSTejun Heo
1630a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE
1631a29815a3SAvi Kivity	hex
1632a29815a3SAvi Kivity	default 0 if X86_32
1633a29815a3SAvi Kivity	default 0xdead000000000000 if X86_64
1634a29815a3SAvi Kivity
16357a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE
16367a67832cSDan Williams	bool
16377a67832cSDan Williams
1638ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY
16397a67832cSDan Williams	tristate "Support non-standard NVDIMMs and ADR protected memory"
16409f53f9faSDan Williams	depends on PHYS_ADDR_T_64BIT
16419f53f9faSDan Williams	depends on BLK_DEV
16427a67832cSDan Williams	select X86_PMEM_LEGACY_DEVICE
16437b27a862SDan Williams	select NUMA_KEEP_MEMINFO if NUMA
16449f53f9faSDan Williams	select LIBNVDIMM
1645ec776ef6SChristoph Hellwig	help
1646ec776ef6SChristoph Hellwig	  Treat memory marked using the non-standard e820 type of 12 as used
1647ec776ef6SChristoph Hellwig	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1648ec776ef6SChristoph Hellwig	  The kernel will offer these regions to the 'pmem' driver so
1649ec776ef6SChristoph Hellwig	  they can be used for persistent storage.
1650ec776ef6SChristoph Hellwig
1651ec776ef6SChristoph Hellwig	  Say Y if unsure.
1652ec776ef6SChristoph Hellwig
1653506f1d07SSam Ravnborgconfig HIGHPTE
1654506f1d07SSam Ravnborg	bool "Allocate 3rd-level pagetables from highmem"
16556fc108a0SJan Beulich	depends on HIGHMEM
1656a7f7f624SMasahiro Yamada	help
1657506f1d07SSam Ravnborg	  The VM uses one page table entry for each page of physical memory.
1658506f1d07SSam Ravnborg	  For systems with a lot of RAM, this can be wasteful of precious
1659506f1d07SSam Ravnborg	  low memory.  Setting this option will put user-space page table
1660506f1d07SSam Ravnborg	  entries in high memory.
1661506f1d07SSam Ravnborg
16629f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION
16639f077871SJeremy Fitzhardinge	bool "Check for low memory corruption"
1664a7f7f624SMasahiro Yamada	help
16659f077871SJeremy Fitzhardinge	  Periodically check for memory corruption in low memory, which
16669f077871SJeremy Fitzhardinge	  is suspected to be caused by BIOS.  Even when enabled in the
16679f077871SJeremy Fitzhardinge	  configuration, it is disabled at runtime.  Enable it by
16689f077871SJeremy Fitzhardinge	  setting "memory_corruption_check=1" on the kernel command
16699f077871SJeremy Fitzhardinge	  line.  By default it scans the low 64k of memory every 60
16709f077871SJeremy Fitzhardinge	  seconds; see the memory_corruption_check_size and
16719f077871SJeremy Fitzhardinge	  memory_corruption_check_period parameters in
16728c27ceffSMauro Carvalho Chehab	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
16739f077871SJeremy Fitzhardinge
16749f077871SJeremy Fitzhardinge	  When enabled with the default parameters, this option has
16759f077871SJeremy Fitzhardinge	  almost no overhead, as it reserves a relatively small amount
16769f077871SJeremy Fitzhardinge	  of memory and scans it infrequently.  It both detects corruption
16779f077871SJeremy Fitzhardinge	  and prevents it from affecting the running system.
16789f077871SJeremy Fitzhardinge
16799f077871SJeremy Fitzhardinge	  It is, however, intended as a diagnostic tool; if repeatable
16809f077871SJeremy Fitzhardinge	  BIOS-originated corruption always affects the same memory,
16819f077871SJeremy Fitzhardinge	  you can use memmap= to prevent the kernel from using that
16829f077871SJeremy Fitzhardinge	  memory.
16839f077871SJeremy Fitzhardinge
1684c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1685c885df50SJeremy Fitzhardinge	bool "Set the default setting of memory_corruption_check"
1686c885df50SJeremy Fitzhardinge	depends on X86_CHECK_BIOS_CORRUPTION
1687c885df50SJeremy Fitzhardinge	default y
1688a7f7f624SMasahiro Yamada	help
1689c885df50SJeremy Fitzhardinge	  Set whether the default state of memory_corruption_check is
1690c885df50SJeremy Fitzhardinge	  on or off.
1691c885df50SJeremy Fitzhardinge
16929ea77bdbSH. Peter Anvinconfig X86_RESERVE_LOW
1693d0cd7425SH. Peter Anvin	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1694d0cd7425SH. Peter Anvin	default 64
1695d0cd7425SH. Peter Anvin	range 4 640
1696a7f7f624SMasahiro Yamada	help
1697d0cd7425SH. Peter Anvin	  Specify the amount of low memory to reserve for the BIOS.
1698fc381519SIngo Molnar
1699d0cd7425SH. Peter Anvin	  The first page contains BIOS data structures that the kernel
1700d0cd7425SH. Peter Anvin	  must not use, so that page must always be reserved.
1701fc381519SIngo Molnar
1702d0cd7425SH. Peter Anvin	  By default we reserve the first 64K of physical RAM, as a
1703d0cd7425SH. Peter Anvin	  number of BIOSes are known to corrupt that memory range
1704d0cd7425SH. Peter Anvin	  during events such as suspend/resume or monitor cable
1705d0cd7425SH. Peter Anvin	  insertion, so it must not be used by the kernel.
1706fc381519SIngo Molnar
1707d0cd7425SH. Peter Anvin	  You can set this to 4 if you are absolutely sure that you
1708d0cd7425SH. Peter Anvin	  trust the BIOS to get all its memory reservations and usages
1709d0cd7425SH. Peter Anvin	  right.  If you know your BIOS have problems beyond the
1710d0cd7425SH. Peter Anvin	  default 64K area, you can set this to 640 to avoid using the
1711d0cd7425SH. Peter Anvin	  entire low memory range.
1712d0cd7425SH. Peter Anvin
1713d0cd7425SH. Peter Anvin	  If you have doubts about the BIOS (e.g. suspend/resume does
1714d0cd7425SH. Peter Anvin	  not work or there's kernel crashes after certain hardware
1715d0cd7425SH. Peter Anvin	  hotplug events) then you might want to enable
1716d0cd7425SH. Peter Anvin	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1717d0cd7425SH. Peter Anvin	  typical corruption patterns.
1718d0cd7425SH. Peter Anvin
1719d0cd7425SH. Peter Anvin	  Leave this to the default value of 64 if you are unsure.
1720fc381519SIngo Molnar
1721506f1d07SSam Ravnborgconfig MATH_EMULATION
1722506f1d07SSam Ravnborg	bool
1723a5b9e5a2SAndy Lutomirski	depends on MODIFY_LDT_SYSCALL
172487d6021bSArnd Bergmann	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1725a7f7f624SMasahiro Yamada	help
1726506f1d07SSam Ravnborg	  Linux can emulate a math coprocessor (used for floating point
1727506f1d07SSam Ravnborg	  operations) if you don't have one. 486DX and Pentium processors have
1728506f1d07SSam Ravnborg	  a math coprocessor built in, 486SX and 386 do not, unless you added
1729506f1d07SSam Ravnborg	  a 487DX or 387, respectively. (The messages during boot time can
1730506f1d07SSam Ravnborg	  give you some hints here ["man dmesg"].) Everyone needs either a
1731506f1d07SSam Ravnborg	  coprocessor or this emulation.
1732506f1d07SSam Ravnborg
1733506f1d07SSam Ravnborg	  If you don't have a math coprocessor, you need to say Y here; if you
1734506f1d07SSam Ravnborg	  say Y here even though you have a coprocessor, the coprocessor will
1735506f1d07SSam Ravnborg	  be used nevertheless. (This behavior can be changed with the kernel
1736506f1d07SSam Ravnborg	  command line option "no387", which comes handy if your coprocessor
1737506f1d07SSam Ravnborg	  is broken. Try "man bootparam" or see the documentation of your boot
1738506f1d07SSam Ravnborg	  loader (lilo or loadlin) about how to pass options to the kernel at
1739506f1d07SSam Ravnborg	  boot time.) This means that it is a good idea to say Y here if you
1740506f1d07SSam Ravnborg	  intend to use this kernel on different machines.
1741506f1d07SSam Ravnborg
1742506f1d07SSam Ravnborg	  More information about the internals of the Linux math coprocessor
1743506f1d07SSam Ravnborg	  emulation can be found in <file:arch/x86/math-emu/README>.
1744506f1d07SSam Ravnborg
1745506f1d07SSam Ravnborg	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1746506f1d07SSam Ravnborg	  kernel, it won't hurt.
1747506f1d07SSam Ravnborg
1748506f1d07SSam Ravnborgconfig MTRR
17496fc108a0SJan Beulich	def_bool y
17506a108a14SDavid Rientjes	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1751a7f7f624SMasahiro Yamada	help
1752506f1d07SSam Ravnborg	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1753506f1d07SSam Ravnborg	  the Memory Type Range Registers (MTRRs) may be used to control
1754506f1d07SSam Ravnborg	  processor access to memory ranges. This is most useful if you have
1755506f1d07SSam Ravnborg	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1756506f1d07SSam Ravnborg	  allows bus write transfers to be combined into a larger transfer
1757506f1d07SSam Ravnborg	  before bursting over the PCI/AGP bus. This can increase performance
1758506f1d07SSam Ravnborg	  of image write operations 2.5 times or more. Saying Y here creates a
1759506f1d07SSam Ravnborg	  /proc/mtrr file which may be used to manipulate your processor's
1760506f1d07SSam Ravnborg	  MTRRs. Typically the X server should use this.
1761506f1d07SSam Ravnborg
1762506f1d07SSam Ravnborg	  This code has a reasonably generic interface so that similar
1763506f1d07SSam Ravnborg	  control registers on other processors can be easily supported
1764506f1d07SSam Ravnborg	  as well:
1765506f1d07SSam Ravnborg
1766506f1d07SSam Ravnborg	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1767506f1d07SSam Ravnborg	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1768506f1d07SSam Ravnborg	  these, the ARRs are used to emulate the MTRRs.
1769506f1d07SSam Ravnborg	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1770506f1d07SSam Ravnborg	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1771506f1d07SSam Ravnborg	  write-combining. All of these processors are supported by this code
1772506f1d07SSam Ravnborg	  and it makes sense to say Y here if you have one of them.
1773506f1d07SSam Ravnborg
1774506f1d07SSam Ravnborg	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1775506f1d07SSam Ravnborg	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1776506f1d07SSam Ravnborg	  can lead to all sorts of problems, so it's good to say Y here.
1777506f1d07SSam Ravnborg
1778506f1d07SSam Ravnborg	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1779506f1d07SSam Ravnborg	  just add about 9 KB to your kernel.
1780506f1d07SSam Ravnborg
1781cb1aaebeSMauro Carvalho Chehab	  See <file:Documentation/x86/mtrr.rst> for more information.
1782506f1d07SSam Ravnborg
178395ffa243SYinghai Luconfig MTRR_SANITIZER
17842ffb3501SYinghai Lu	def_bool y
178595ffa243SYinghai Lu	prompt "MTRR cleanup support"
178695ffa243SYinghai Lu	depends on MTRR
1787a7f7f624SMasahiro Yamada	help
1788aba3728cSThomas Gleixner	  Convert MTRR layout from continuous to discrete, so X drivers can
1789aba3728cSThomas Gleixner	  add writeback entries.
179095ffa243SYinghai Lu
1791aba3728cSThomas Gleixner	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1792692105b8SMatt LaPlante	  The largest mtrr entry size for a continuous block can be set with
1793aba3728cSThomas Gleixner	  mtrr_chunk_size.
179495ffa243SYinghai Lu
17952ffb3501SYinghai Lu	  If unsure, say Y.
179695ffa243SYinghai Lu
179795ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT
1798f5098d62SYinghai Lu	int "MTRR cleanup enable value (0-1)"
1799f5098d62SYinghai Lu	range 0 1
1800f5098d62SYinghai Lu	default "0"
180195ffa243SYinghai Lu	depends on MTRR_SANITIZER
1802a7f7f624SMasahiro Yamada	help
1803f5098d62SYinghai Lu	  Enable mtrr cleanup default value
180495ffa243SYinghai Lu
180512031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
180612031a62SYinghai Lu	int "MTRR cleanup spare reg num (0-7)"
180712031a62SYinghai Lu	range 0 7
180812031a62SYinghai Lu	default "1"
180912031a62SYinghai Lu	depends on MTRR_SANITIZER
1810a7f7f624SMasahiro Yamada	help
181112031a62SYinghai Lu	  mtrr cleanup spare entries default, it can be changed via
1812aba3728cSThomas Gleixner	  mtrr_spare_reg_nr=N on the kernel command line.
181312031a62SYinghai Lu
18142e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT
18156fc108a0SJan Beulich	def_bool y
18166a108a14SDavid Rientjes	prompt "x86 PAT support" if EXPERT
18172a8a2719SIngo Molnar	depends on MTRR
1818a7f7f624SMasahiro Yamada	help
18192e5d9c85Svenkatesh.pallipadi@intel.com	  Use PAT attributes to setup page level cache control.
1820042b78e4SVenki Pallipadi
18212e5d9c85Svenkatesh.pallipadi@intel.com	  PATs are the modern equivalents of MTRRs and are much more
18222e5d9c85Svenkatesh.pallipadi@intel.com	  flexible than MTRRs.
18232e5d9c85Svenkatesh.pallipadi@intel.com
18242e5d9c85Svenkatesh.pallipadi@intel.com	  Say N here if you see bootup problems (boot crash, boot hang,
1825042b78e4SVenki Pallipadi	  spontaneous reboots) or a non-working video driver.
18262e5d9c85Svenkatesh.pallipadi@intel.com
18272e5d9c85Svenkatesh.pallipadi@intel.com	  If unsure, say Y.
18282e5d9c85Svenkatesh.pallipadi@intel.com
182946cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED
183046cf98cdSVenkatesh Pallipadi	def_bool y
183146cf98cdSVenkatesh Pallipadi	depends on X86_PAT
183246cf98cdSVenkatesh Pallipadi
1833628c6246SH. Peter Anvinconfig ARCH_RANDOM
1834628c6246SH. Peter Anvin	def_bool y
1835628c6246SH. Peter Anvin	prompt "x86 architectural random number generator" if EXPERT
1836a7f7f624SMasahiro Yamada	help
1837628c6246SH. Peter Anvin	  Enable the x86 architectural RDRAND instruction
1838628c6246SH. Peter Anvin	  (Intel Bull Mountain technology) to generate random numbers.
1839628c6246SH. Peter Anvin	  If supported, this is a high bandwidth, cryptographically
1840628c6246SH. Peter Anvin	  secure hardware random number generator.
1841628c6246SH. Peter Anvin
184251ae4a2dSH. Peter Anvinconfig X86_SMAP
184351ae4a2dSH. Peter Anvin	def_bool y
184451ae4a2dSH. Peter Anvin	prompt "Supervisor Mode Access Prevention" if EXPERT
1845a7f7f624SMasahiro Yamada	help
184651ae4a2dSH. Peter Anvin	  Supervisor Mode Access Prevention (SMAP) is a security
184751ae4a2dSH. Peter Anvin	  feature in newer Intel processors.  There is a small
184851ae4a2dSH. Peter Anvin	  performance cost if this enabled and turned on; there is
184951ae4a2dSH. Peter Anvin	  also a small increase in the kernel size if this is enabled.
185051ae4a2dSH. Peter Anvin
185151ae4a2dSH. Peter Anvin	  If unsure, say Y.
185251ae4a2dSH. Peter Anvin
1853b971880fSBabu Mogerconfig X86_UMIP
1854796ebc81SRicardo Neri	def_bool y
1855b971880fSBabu Moger	prompt "User Mode Instruction Prevention" if EXPERT
1856a7f7f624SMasahiro Yamada	help
1857b971880fSBabu Moger	  User Mode Instruction Prevention (UMIP) is a security feature in
1858b971880fSBabu Moger	  some x86 processors. If enabled, a general protection fault is
1859b971880fSBabu Moger	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1860b971880fSBabu Moger	  executed in user mode. These instructions unnecessarily expose
1861b971880fSBabu Moger	  information about the hardware state.
1862796ebc81SRicardo Neri
1863796ebc81SRicardo Neri	  The vast majority of applications do not use these instructions.
1864796ebc81SRicardo Neri	  For the very few that do, software emulation is provided in
1865796ebc81SRicardo Neri	  specific cases in protected and virtual-8086 modes. Emulated
1866796ebc81SRicardo Neri	  results are dummy.
1867aa35f896SRicardo Neri
186835e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS
186938f3e775SBabu Moger	prompt "Memory Protection Keys"
187035e97790SDave Hansen	def_bool y
1871284244a9SDave Hansen	# Note: only available in 64-bit mode
187238f3e775SBabu Moger	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
187352c8e601SIngo Molnar	select ARCH_USES_HIGH_VMA_FLAGS
187452c8e601SIngo Molnar	select ARCH_HAS_PKEYS
1875a7f7f624SMasahiro Yamada	help
1876284244a9SDave Hansen	  Memory Protection Keys provides a mechanism for enforcing
1877284244a9SDave Hansen	  page-based protections, but without requiring modification of the
1878284244a9SDave Hansen	  page tables when an application changes protection domains.
1879284244a9SDave Hansen
18801eecbcdcSMauro Carvalho Chehab	  For details, see Documentation/core-api/protection-keys.rst
1881284244a9SDave Hansen
1882284244a9SDave Hansen	  If unsure, say y.
188335e97790SDave Hansen
1884db616173SMichal Hockochoice
1885db616173SMichal Hocko	prompt "TSX enable mode"
1886db616173SMichal Hocko	depends on CPU_SUP_INTEL
1887db616173SMichal Hocko	default X86_INTEL_TSX_MODE_OFF
1888db616173SMichal Hocko	help
1889db616173SMichal Hocko	  Intel's TSX (Transactional Synchronization Extensions) feature
1890db616173SMichal Hocko	  allows to optimize locking protocols through lock elision which
1891db616173SMichal Hocko	  can lead to a noticeable performance boost.
1892db616173SMichal Hocko
1893db616173SMichal Hocko	  On the other hand it has been shown that TSX can be exploited
1894db616173SMichal Hocko	  to form side channel attacks (e.g. TAA) and chances are there
1895db616173SMichal Hocko	  will be more of those attacks discovered in the future.
1896db616173SMichal Hocko
1897db616173SMichal Hocko	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1898db616173SMichal Hocko	  might override this decision by tsx=on the command line parameter.
1899db616173SMichal Hocko	  Even with TSX enabled, the kernel will attempt to enable the best
1900db616173SMichal Hocko	  possible TAA mitigation setting depending on the microcode available
1901db616173SMichal Hocko	  for the particular machine.
1902db616173SMichal Hocko
1903db616173SMichal Hocko	  This option allows to set the default tsx mode between tsx=on, =off
1904db616173SMichal Hocko	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1905db616173SMichal Hocko	  details.
1906db616173SMichal Hocko
1907db616173SMichal Hocko	  Say off if not sure, auto if TSX is in use but it should be used on safe
1908db616173SMichal Hocko	  platforms or on if TSX is in use and the security aspect of tsx is not
1909db616173SMichal Hocko	  relevant.
1910db616173SMichal Hocko
1911db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF
1912db616173SMichal Hocko	bool "off"
1913db616173SMichal Hocko	help
1914db616173SMichal Hocko	  TSX is disabled if possible - equals to tsx=off command line parameter.
1915db616173SMichal Hocko
1916db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON
1917db616173SMichal Hocko	bool "on"
1918db616173SMichal Hocko	help
1919db616173SMichal Hocko	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1920db616173SMichal Hocko	  line parameter.
1921db616173SMichal Hocko
1922db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO
1923db616173SMichal Hocko	bool "auto"
1924db616173SMichal Hocko	help
1925db616173SMichal Hocko	  TSX is enabled on TSX capable HW that is believed to be safe against
1926db616173SMichal Hocko	  side channel attacks- equals the tsx=auto command line parameter.
1927db616173SMichal Hockoendchoice
1928db616173SMichal Hocko
1929506f1d07SSam Ravnborgconfig EFI
19309ba16087SJan Beulich	bool "EFI runtime service support"
19315b83683fSHuang, Ying	depends on ACPI
1932f6ce5002SSergey Vlasov	select UCS2_STRING
1933022ee6c5SArd Biesheuvel	select EFI_RUNTIME_WRAPPERS
1934a7f7f624SMasahiro Yamada	help
19358b2cb7a8SHuang, Ying	  This enables the kernel to use EFI runtime services that are
1936506f1d07SSam Ravnborg	  available (such as the EFI variable services).
1937506f1d07SSam Ravnborg
19388b2cb7a8SHuang, Ying	  This option is only useful on systems that have EFI firmware.
19398b2cb7a8SHuang, Ying	  In addition, you should use the latest ELILO loader available
19408b2cb7a8SHuang, Ying	  at <http://elilo.sourceforge.net> in order to take advantage
19418b2cb7a8SHuang, Ying	  of EFI runtime services. However, even with this option, the
19428b2cb7a8SHuang, Ying	  resultant kernel should continue to boot on existing non-EFI
19438b2cb7a8SHuang, Ying	  platforms.
1944506f1d07SSam Ravnborg
1945291f3632SMatt Flemingconfig EFI_STUB
1946291f3632SMatt Fleming	bool "EFI stub support"
1947b16d8c23SMatt Fleming	depends on EFI && !X86_USE_3DNOW
19488f24f8c2SArd Biesheuvel	depends on $(cc-option,-mabi=ms) || X86_32
19497b2a583aSMatt Fleming	select RELOCATABLE
1950a7f7f624SMasahiro Yamada	help
1951291f3632SMatt Fleming	  This kernel feature allows a bzImage to be loaded directly
1952291f3632SMatt Fleming	  by EFI firmware without the use of a bootloader.
1953291f3632SMatt Fleming
19544f4cfa6cSMauro Carvalho Chehab	  See Documentation/admin-guide/efi-stub.rst for more information.
19550c759662SMatt Fleming
19567d453eeeSMatt Flemingconfig EFI_MIXED
19577d453eeeSMatt Fleming	bool "EFI mixed-mode support"
19587d453eeeSMatt Fleming	depends on EFI_STUB && X86_64
1959a7f7f624SMasahiro Yamada	help
19607d453eeeSMatt Fleming	   Enabling this feature allows a 64-bit kernel to be booted
19617d453eeeSMatt Fleming	   on a 32-bit firmware, provided that your CPU supports 64-bit
19627d453eeeSMatt Fleming	   mode.
19637d453eeeSMatt Fleming
19647d453eeeSMatt Fleming	   Note that it is not possible to boot a mixed-mode enabled
19657d453eeeSMatt Fleming	   kernel via the EFI boot stub - a bootloader that supports
19667d453eeeSMatt Fleming	   the EFI handover protocol must be used.
19677d453eeeSMatt Fleming
19687d453eeeSMatt Fleming	   If unsure, say N.
19697d453eeeSMatt Fleming
1970506f1d07SSam Ravnborgconfig SECCOMP
19713c2362e6SHarvey Harrison	def_bool y
19723c2362e6SHarvey Harrison	prompt "Enable seccomp to safely compute untrusted bytecode"
1973a7f7f624SMasahiro Yamada	help
1974506f1d07SSam Ravnborg	  This kernel feature is useful for number crunching applications
1975506f1d07SSam Ravnborg	  that may need to compute untrusted bytecode during their
1976506f1d07SSam Ravnborg	  execution. By using pipes or other transports made available to
1977506f1d07SSam Ravnborg	  the process as file descriptors supporting the read/write
1978506f1d07SSam Ravnborg	  syscalls, it's possible to isolate those applications in
1979506f1d07SSam Ravnborg	  their own address space using seccomp. Once seccomp is
19809c0bbee8SAlexey Dobriyan	  enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1981506f1d07SSam Ravnborg	  and the task is only allowed to execute a few safe syscalls
1982506f1d07SSam Ravnborg	  defined by each seccomp mode.
1983506f1d07SSam Ravnborg
1984506f1d07SSam Ravnborg	  If unsure, say Y. Only embedded should say N here.
1985506f1d07SSam Ravnborg
19868636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz"
1987506f1d07SSam Ravnborg
1988506f1d07SSam Ravnborgconfig KEXEC
1989506f1d07SSam Ravnborg	bool "kexec system call"
19902965faa5SDave Young	select KEXEC_CORE
1991a7f7f624SMasahiro Yamada	help
1992506f1d07SSam Ravnborg	  kexec is a system call that implements the ability to shutdown your
1993506f1d07SSam Ravnborg	  current kernel, and to start another kernel.  It is like a reboot
1994506f1d07SSam Ravnborg	  but it is independent of the system firmware.   And like a reboot
1995506f1d07SSam Ravnborg	  you can start any kernel with it, not just Linux.
1996506f1d07SSam Ravnborg
1997506f1d07SSam Ravnborg	  The name comes from the similarity to the exec system call.
1998506f1d07SSam Ravnborg
1999506f1d07SSam Ravnborg	  It is an ongoing process to be certain the hardware in a machine
2000506f1d07SSam Ravnborg	  is properly shutdown, so do not be surprised if this code does not
2001bf220695SGeert Uytterhoeven	  initially work for you.  As of this writing the exact hardware
2002bf220695SGeert Uytterhoeven	  interface is strongly in flux, so no good recommendation can be
2003bf220695SGeert Uytterhoeven	  made.
2004506f1d07SSam Ravnborg
200574ca317cSVivek Goyalconfig KEXEC_FILE
200674ca317cSVivek Goyal	bool "kexec file based system call"
20072965faa5SDave Young	select KEXEC_CORE
200874ca317cSVivek Goyal	select BUILD_BIN2C
200974ca317cSVivek Goyal	depends on X86_64
201074ca317cSVivek Goyal	depends on CRYPTO=y
201174ca317cSVivek Goyal	depends on CRYPTO_SHA256=y
2012a7f7f624SMasahiro Yamada	help
201374ca317cSVivek Goyal	  This is new version of kexec system call. This system call is
201474ca317cSVivek Goyal	  file based and takes file descriptors as system call argument
201574ca317cSVivek Goyal	  for kernel and initramfs as opposed to list of segments as
201674ca317cSVivek Goyal	  accepted by previous system call.
201774ca317cSVivek Goyal
2018b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY
2019b799a09fSAKASHI Takahiro	def_bool KEXEC_FILE
2020b799a09fSAKASHI Takahiro
202199d5cadfSJiri Bohacconfig KEXEC_SIG
20228e7d8381SVivek Goyal	bool "Verify kernel signature during kexec_file_load() syscall"
202374ca317cSVivek Goyal	depends on KEXEC_FILE
2024a7f7f624SMasahiro Yamada	help
202599d5cadfSJiri Bohac
202699d5cadfSJiri Bohac	  This option makes the kexec_file_load() syscall check for a valid
202799d5cadfSJiri Bohac	  signature of the kernel image.  The image can still be loaded without
202899d5cadfSJiri Bohac	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
202999d5cadfSJiri Bohac	  there's a signature that we can check, then it must be valid.
203099d5cadfSJiri Bohac
203199d5cadfSJiri Bohac	  In addition to this option, you need to enable signature
203299d5cadfSJiri Bohac	  verification for the corresponding kernel image type being
203399d5cadfSJiri Bohac	  loaded in order for this to work.
203499d5cadfSJiri Bohac
203599d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE
203699d5cadfSJiri Bohac	bool "Require a valid signature in kexec_file_load() syscall"
203799d5cadfSJiri Bohac	depends on KEXEC_SIG
2038a7f7f624SMasahiro Yamada	help
20398e7d8381SVivek Goyal	  This option makes kernel signature verification mandatory for
2040d8eb8940SBorislav Petkov	  the kexec_file_load() syscall.
20418e7d8381SVivek Goyal
20428e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG
20438e7d8381SVivek Goyal	bool "Enable bzImage signature verification support"
204499d5cadfSJiri Bohac	depends on KEXEC_SIG
20458e7d8381SVivek Goyal	depends on SIGNED_PE_FILE_VERIFICATION
20468e7d8381SVivek Goyal	select SYSTEM_TRUSTED_KEYRING
2047a7f7f624SMasahiro Yamada	help
20488e7d8381SVivek Goyal	  Enable bzImage signature verification support.
20498e7d8381SVivek Goyal
2050506f1d07SSam Ravnborgconfig CRASH_DUMP
205104b69447SPavel Machek	bool "kernel crash dumps"
2052506f1d07SSam Ravnborg	depends on X86_64 || (X86_32 && HIGHMEM)
2053a7f7f624SMasahiro Yamada	help
2054506f1d07SSam Ravnborg	  Generate crash dump after being started by kexec.
2055506f1d07SSam Ravnborg	  This should be normally only set in special crash dump kernels
2056506f1d07SSam Ravnborg	  which are loaded in the main kernel with kexec-tools into
2057506f1d07SSam Ravnborg	  a specially reserved region and then later executed after
2058506f1d07SSam Ravnborg	  a crash by kdump/kexec. The crash dump kernel must be compiled
2059506f1d07SSam Ravnborg	  to a memory address not used by the main kernel or BIOS using
2060506f1d07SSam Ravnborg	  PHYSICAL_START, or it must be built as a relocatable image
2061506f1d07SSam Ravnborg	  (CONFIG_RELOCATABLE=y).
2062330d4810SMauro Carvalho Chehab	  For more details see Documentation/admin-guide/kdump/kdump.rst
2063506f1d07SSam Ravnborg
20643ab83521SHuang Yingconfig KEXEC_JUMP
20656ea30386SKees Cook	bool "kexec jump"
2066fee7b0d8SHuang Ying	depends on KEXEC && HIBERNATION
2067a7f7f624SMasahiro Yamada	help
206889081d17SHuang Ying	  Jump between original kernel and kexeced kernel and invoke
206989081d17SHuang Ying	  code in physical address mode via KEXEC
20703ab83521SHuang Ying
2071506f1d07SSam Ravnborgconfig PHYSICAL_START
20726a108a14SDavid Rientjes	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2073ceefccc9SH. Peter Anvin	default "0x1000000"
2074a7f7f624SMasahiro Yamada	help
2075506f1d07SSam Ravnborg	  This gives the physical address where the kernel is loaded.
2076506f1d07SSam Ravnborg
2077506f1d07SSam Ravnborg	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2078506f1d07SSam Ravnborg	  bzImage will decompress itself to above physical address and
2079506f1d07SSam Ravnborg	  run from there. Otherwise, bzImage will run from the address where
2080506f1d07SSam Ravnborg	  it has been loaded by the boot loader and will ignore above physical
2081506f1d07SSam Ravnborg	  address.
2082506f1d07SSam Ravnborg
2083506f1d07SSam Ravnborg	  In normal kdump cases one does not have to set/change this option
2084506f1d07SSam Ravnborg	  as now bzImage can be compiled as a completely relocatable image
2085506f1d07SSam Ravnborg	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2086506f1d07SSam Ravnborg	  address. This option is mainly useful for the folks who don't want
2087506f1d07SSam Ravnborg	  to use a bzImage for capturing the crash dump and want to use a
2088506f1d07SSam Ravnborg	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2089506f1d07SSam Ravnborg	  to be specifically compiled to run from a specific memory area
2090506f1d07SSam Ravnborg	  (normally a reserved region) and this option comes handy.
2091506f1d07SSam Ravnborg
2092ceefccc9SH. Peter Anvin	  So if you are using bzImage for capturing the crash dump,
2093ceefccc9SH. Peter Anvin	  leave the value here unchanged to 0x1000000 and set
2094ceefccc9SH. Peter Anvin	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2095ceefccc9SH. Peter Anvin	  for capturing the crash dump change this value to start of
2096ceefccc9SH. Peter Anvin	  the reserved region.  In other words, it can be set based on
2097ceefccc9SH. Peter Anvin	  the "X" value as specified in the "crashkernel=YM@XM"
2098ceefccc9SH. Peter Anvin	  command line boot parameter passed to the panic-ed
2099330d4810SMauro Carvalho Chehab	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2100ceefccc9SH. Peter Anvin	  for more details about crash dumps.
2101506f1d07SSam Ravnborg
2102506f1d07SSam Ravnborg	  Usage of bzImage for capturing the crash dump is recommended as
2103506f1d07SSam Ravnborg	  one does not have to build two kernels. Same kernel can be used
2104506f1d07SSam Ravnborg	  as production kernel and capture kernel. Above option should have
2105506f1d07SSam Ravnborg	  gone away after relocatable bzImage support is introduced. But it
2106506f1d07SSam Ravnborg	  is present because there are users out there who continue to use
2107506f1d07SSam Ravnborg	  vmlinux for dump capture. This option should go away down the
2108506f1d07SSam Ravnborg	  line.
2109506f1d07SSam Ravnborg
2110506f1d07SSam Ravnborg	  Don't change this unless you know what you are doing.
2111506f1d07SSam Ravnborg
2112506f1d07SSam Ravnborgconfig RELOCATABLE
211326717808SH. Peter Anvin	bool "Build a relocatable kernel"
211426717808SH. Peter Anvin	default y
2115a7f7f624SMasahiro Yamada	help
2116506f1d07SSam Ravnborg	  This builds a kernel image that retains relocation information
2117506f1d07SSam Ravnborg	  so it can be loaded someplace besides the default 1MB.
2118506f1d07SSam Ravnborg	  The relocations tend to make the kernel binary about 10% larger,
2119506f1d07SSam Ravnborg	  but are discarded at runtime.
2120506f1d07SSam Ravnborg
2121506f1d07SSam Ravnborg	  One use is for the kexec on panic case where the recovery kernel
2122506f1d07SSam Ravnborg	  must live at a different physical address than the primary
2123506f1d07SSam Ravnborg	  kernel.
2124506f1d07SSam Ravnborg
2125506f1d07SSam Ravnborg	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2126506f1d07SSam Ravnborg	  it has been loaded at and the compile time physical address
21278ab3820fSKees Cook	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2128506f1d07SSam Ravnborg
21298ab3820fSKees Cookconfig RANDOMIZE_BASE
2130e8581e3dSBaoquan He	bool "Randomize the address of the kernel image (KASLR)"
21318ab3820fSKees Cook	depends on RELOCATABLE
21326807c846SIngo Molnar	default y
2133a7f7f624SMasahiro Yamada	help
2134e8581e3dSBaoquan He	  In support of Kernel Address Space Layout Randomization (KASLR),
2135e8581e3dSBaoquan He	  this randomizes the physical address at which the kernel image
2136e8581e3dSBaoquan He	  is decompressed and the virtual address where the kernel
2137e8581e3dSBaoquan He	  image is mapped, as a security feature that deters exploit
2138e8581e3dSBaoquan He	  attempts relying on knowledge of the location of kernel
2139e8581e3dSBaoquan He	  code internals.
2140e8581e3dSBaoquan He
2141ed9f007eSKees Cook	  On 64-bit, the kernel physical and virtual addresses are
2142ed9f007eSKees Cook	  randomized separately. The physical address will be anywhere
2143ed9f007eSKees Cook	  between 16MB and the top of physical memory (up to 64TB). The
2144ed9f007eSKees Cook	  virtual address will be randomized from 16MB up to 1GB (9 bits
2145ed9f007eSKees Cook	  of entropy). Note that this also reduces the memory space
2146ed9f007eSKees Cook	  available to kernel modules from 1.5GB to 1GB.
2147ed9f007eSKees Cook
2148ed9f007eSKees Cook	  On 32-bit, the kernel physical and virtual addresses are
2149ed9f007eSKees Cook	  randomized together. They will be randomized from 16MB up to
2150ed9f007eSKees Cook	  512MB (8 bits of entropy).
21518ab3820fSKees Cook
2152a653f356SKees Cook	  Entropy is generated using the RDRAND instruction if it is
2153e8581e3dSBaoquan He	  supported. If RDTSC is supported, its value is mixed into
2154e8581e3dSBaoquan He	  the entropy pool as well. If neither RDRAND nor RDTSC are
2155ed9f007eSKees Cook	  supported, then entropy is read from the i8254 timer. The
2156ed9f007eSKees Cook	  usable entropy is limited by the kernel being built using
2157ed9f007eSKees Cook	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2158ed9f007eSKees Cook	  minimum of 2MB. As a result, only 10 bits of entropy are
2159ed9f007eSKees Cook	  theoretically possible, but the implementations are further
2160ed9f007eSKees Cook	  limited due to memory layouts.
2161e8581e3dSBaoquan He
21626807c846SIngo Molnar	  If unsure, say Y.
2163da2b6fb9SKees Cook
21648ab3820fSKees Cook# Relocation on x86 needs some additional build support
2165845adf72SH. Peter Anvinconfig X86_NEED_RELOCS
2166845adf72SH. Peter Anvin	def_bool y
21678ab3820fSKees Cook	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2168845adf72SH. Peter Anvin
2169506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN
2170a0215061SKees Cook	hex "Alignment value to which kernel should be aligned"
21718ab3820fSKees Cook	default "0x200000"
2172a0215061SKees Cook	range 0x2000 0x1000000 if X86_32
2173a0215061SKees Cook	range 0x200000 0x1000000 if X86_64
2174a7f7f624SMasahiro Yamada	help
2175506f1d07SSam Ravnborg	  This value puts the alignment restrictions on physical address
2176506f1d07SSam Ravnborg	  where kernel is loaded and run from. Kernel is compiled for an
2177506f1d07SSam Ravnborg	  address which meets above alignment restriction.
2178506f1d07SSam Ravnborg
2179506f1d07SSam Ravnborg	  If bootloader loads the kernel at a non-aligned address and
2180506f1d07SSam Ravnborg	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2181506f1d07SSam Ravnborg	  address aligned to above value and run from there.
2182506f1d07SSam Ravnborg
2183506f1d07SSam Ravnborg	  If bootloader loads the kernel at a non-aligned address and
2184506f1d07SSam Ravnborg	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2185506f1d07SSam Ravnborg	  load address and decompress itself to the address it has been
2186506f1d07SSam Ravnborg	  compiled for and run from there. The address for which kernel is
2187506f1d07SSam Ravnborg	  compiled already meets above alignment restrictions. Hence the
2188506f1d07SSam Ravnborg	  end result is that kernel runs from a physical address meeting
2189506f1d07SSam Ravnborg	  above alignment restrictions.
2190506f1d07SSam Ravnborg
2191a0215061SKees Cook	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2192a0215061SKees Cook	  this value must be a multiple of 0x200000.
2193a0215061SKees Cook
2194506f1d07SSam Ravnborg	  Don't change this unless you know what you are doing.
2195506f1d07SSam Ravnborg
2196eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT
2197eedb92abSKirill A. Shutemov	bool
2198a7f7f624SMasahiro Yamada	help
2199eedb92abSKirill A. Shutemov	  This option makes base addresses of vmalloc and vmemmap as well as
2200eedb92abSKirill A. Shutemov	  __PAGE_OFFSET movable during boot.
2201eedb92abSKirill A. Shutemov
22020483e1faSThomas Garnierconfig RANDOMIZE_MEMORY
22030483e1faSThomas Garnier	bool "Randomize the kernel memory sections"
22040483e1faSThomas Garnier	depends on X86_64
22050483e1faSThomas Garnier	depends on RANDOMIZE_BASE
2206eedb92abSKirill A. Shutemov	select DYNAMIC_MEMORY_LAYOUT
22070483e1faSThomas Garnier	default RANDOMIZE_BASE
2208a7f7f624SMasahiro Yamada	help
22090483e1faSThomas Garnier	   Randomizes the base virtual address of kernel memory sections
22100483e1faSThomas Garnier	   (physical memory mapping, vmalloc & vmemmap). This security feature
22110483e1faSThomas Garnier	   makes exploits relying on predictable memory locations less reliable.
22120483e1faSThomas Garnier
22130483e1faSThomas Garnier	   The order of allocations remains unchanged. Entropy is generated in
22140483e1faSThomas Garnier	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
22150483e1faSThomas Garnier	   configuration have in average 30,000 different possible virtual
22160483e1faSThomas Garnier	   addresses for each memory section.
22170483e1faSThomas Garnier
22186807c846SIngo Molnar	   If unsure, say Y.
22190483e1faSThomas Garnier
222090397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING
222190397a41SThomas Garnier	hex "Physical memory mapping padding" if EXPERT
222290397a41SThomas Garnier	depends on RANDOMIZE_MEMORY
222390397a41SThomas Garnier	default "0xa" if MEMORY_HOTPLUG
222490397a41SThomas Garnier	default "0x0"
222590397a41SThomas Garnier	range 0x1 0x40 if MEMORY_HOTPLUG
222690397a41SThomas Garnier	range 0x0 0x40
2227a7f7f624SMasahiro Yamada	help
222890397a41SThomas Garnier	   Define the padding in terabytes added to the existing physical
222990397a41SThomas Garnier	   memory size during kernel memory randomization. It is useful
223090397a41SThomas Garnier	   for memory hotplug support but reduces the entropy available for
223190397a41SThomas Garnier	   address randomization.
223290397a41SThomas Garnier
223390397a41SThomas Garnier	   If unsure, leave at the default value.
223490397a41SThomas Garnier
2235506f1d07SSam Ravnborgconfig HOTPLUG_CPU
2236bebd024eSThomas Gleixner	def_bool y
223740b31360SStephen Rothwell	depends on SMP
2238506f1d07SSam Ravnborg
223980aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0
224080aa1dffSFenghua Yu	bool "Set default setting of cpu0_hotpluggable"
22412c922cd0SKees Cook	depends on HOTPLUG_CPU
2242a7f7f624SMasahiro Yamada	help
224380aa1dffSFenghua Yu	  Set whether default state of cpu0_hotpluggable is on or off.
224480aa1dffSFenghua Yu
224580aa1dffSFenghua Yu	  Say Y here to enable CPU0 hotplug by default. If this switch
224680aa1dffSFenghua Yu	  is turned on, there is no need to give cpu0_hotplug kernel
224780aa1dffSFenghua Yu	  parameter and the CPU0 hotplug feature is enabled by default.
224880aa1dffSFenghua Yu
224980aa1dffSFenghua Yu	  Please note: there are two known CPU0 dependencies if you want
225080aa1dffSFenghua Yu	  to enable the CPU0 hotplug feature either by this switch or by
225180aa1dffSFenghua Yu	  cpu0_hotplug kernel parameter.
225280aa1dffSFenghua Yu
225380aa1dffSFenghua Yu	  First, resume from hibernate or suspend always starts from CPU0.
225480aa1dffSFenghua Yu	  So hibernate and suspend are prevented if CPU0 is offline.
225580aa1dffSFenghua Yu
225680aa1dffSFenghua Yu	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
225780aa1dffSFenghua Yu	  offline if any interrupt can not migrate out of CPU0. There may
225880aa1dffSFenghua Yu	  be other CPU0 dependencies.
225980aa1dffSFenghua Yu
226080aa1dffSFenghua Yu	  Please make sure the dependencies are under your control before
226180aa1dffSFenghua Yu	  you enable this feature.
226280aa1dffSFenghua Yu
226380aa1dffSFenghua Yu	  Say N if you don't want to enable CPU0 hotplug feature by default.
226480aa1dffSFenghua Yu	  You still can enable the CPU0 hotplug feature at boot by kernel
226580aa1dffSFenghua Yu	  parameter cpu0_hotplug.
226680aa1dffSFenghua Yu
2267a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0
2268a71c8bc5SFenghua Yu	def_bool n
2269a71c8bc5SFenghua Yu	prompt "Debug CPU0 hotplug"
22702c922cd0SKees Cook	depends on HOTPLUG_CPU
2271a7f7f624SMasahiro Yamada	help
2272a71c8bc5SFenghua Yu	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2273a71c8bc5SFenghua Yu	  soon as possible and boots up userspace with CPU0 offlined. User
2274a71c8bc5SFenghua Yu	  can online CPU0 back after boot time.
2275a71c8bc5SFenghua Yu
2276a71c8bc5SFenghua Yu	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2277a71c8bc5SFenghua Yu	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2278a71c8bc5SFenghua Yu	  compilation or giving cpu0_hotplug kernel parameter at boot.
2279a71c8bc5SFenghua Yu
2280a71c8bc5SFenghua Yu	  If unsure, say N.
2281a71c8bc5SFenghua Yu
2282506f1d07SSam Ravnborgconfig COMPAT_VDSO
2283b0b49f26SAndy Lutomirski	def_bool n
2284b0b49f26SAndy Lutomirski	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2285953fee1dSIngo Molnar	depends on COMPAT_32
2286a7f7f624SMasahiro Yamada	help
2287b0b49f26SAndy Lutomirski	  Certain buggy versions of glibc will crash if they are
2288b0b49f26SAndy Lutomirski	  presented with a 32-bit vDSO that is not mapped at the address
2289b0b49f26SAndy Lutomirski	  indicated in its segment table.
2290e84446deSRandy Dunlap
2291b0b49f26SAndy Lutomirski	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2292b0b49f26SAndy Lutomirski	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2293b0b49f26SAndy Lutomirski	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2294b0b49f26SAndy Lutomirski	  the only released version with the bug, but OpenSUSE 9
2295b0b49f26SAndy Lutomirski	  contains a buggy "glibc 2.3.2".
2296506f1d07SSam Ravnborg
2297b0b49f26SAndy Lutomirski	  The symptom of the bug is that everything crashes on startup, saying:
2298b0b49f26SAndy Lutomirski	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2299b0b49f26SAndy Lutomirski
2300b0b49f26SAndy Lutomirski	  Saying Y here changes the default value of the vdso32 boot
2301b0b49f26SAndy Lutomirski	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2302b0b49f26SAndy Lutomirski	  This works around the glibc bug but hurts performance.
2303b0b49f26SAndy Lutomirski
2304b0b49f26SAndy Lutomirski	  If unsure, say N: if you are compiling your own kernel, you
2305b0b49f26SAndy Lutomirski	  are unlikely to be using a buggy version of glibc.
2306506f1d07SSam Ravnborg
23073dc33bd3SKees Cookchoice
23083dc33bd3SKees Cook	prompt "vsyscall table for legacy applications"
23093dc33bd3SKees Cook	depends on X86_64
2310625b7b7fSAndy Lutomirski	default LEGACY_VSYSCALL_XONLY
23113dc33bd3SKees Cook	help
23123dc33bd3SKees Cook	  Legacy user code that does not know how to find the vDSO expects
23133dc33bd3SKees Cook	  to be able to issue three syscalls by calling fixed addresses in
23143dc33bd3SKees Cook	  kernel space. Since this location is not randomized with ASLR,
23153dc33bd3SKees Cook	  it can be used to assist security vulnerability exploitation.
23163dc33bd3SKees Cook
23173dc33bd3SKees Cook	  This setting can be changed at boot time via the kernel command
2318bd49e16eSAndy Lutomirski	  line parameter vsyscall=[emulate|xonly|none].
23193dc33bd3SKees Cook
23203dc33bd3SKees Cook	  On a system with recent enough glibc (2.14 or newer) and no
23213dc33bd3SKees Cook	  static binaries, you can say None without a performance penalty
23223dc33bd3SKees Cook	  to improve security.
23233dc33bd3SKees Cook
2324bd49e16eSAndy Lutomirski	  If unsure, select "Emulate execution only".
23253dc33bd3SKees Cook
23263dc33bd3SKees Cook	config LEGACY_VSYSCALL_EMULATE
2327bd49e16eSAndy Lutomirski		bool "Full emulation"
23283dc33bd3SKees Cook		help
2329bd49e16eSAndy Lutomirski		  The kernel traps and emulates calls into the fixed vsyscall
2330bd49e16eSAndy Lutomirski		  address mapping. This makes the mapping non-executable, but
2331bd49e16eSAndy Lutomirski		  it still contains readable known contents, which could be
2332bd49e16eSAndy Lutomirski		  used in certain rare security vulnerability exploits. This
2333bd49e16eSAndy Lutomirski		  configuration is recommended when using legacy userspace
2334bd49e16eSAndy Lutomirski		  that still uses vsyscalls along with legacy binary
2335bd49e16eSAndy Lutomirski		  instrumentation tools that require code to be readable.
2336bd49e16eSAndy Lutomirski
2337bd49e16eSAndy Lutomirski		  An example of this type of legacy userspace is running
2338bd49e16eSAndy Lutomirski		  Pin on an old binary that still uses vsyscalls.
2339bd49e16eSAndy Lutomirski
2340bd49e16eSAndy Lutomirski	config LEGACY_VSYSCALL_XONLY
2341bd49e16eSAndy Lutomirski		bool "Emulate execution only"
2342bd49e16eSAndy Lutomirski		help
2343bd49e16eSAndy Lutomirski		  The kernel traps and emulates calls into the fixed vsyscall
2344bd49e16eSAndy Lutomirski		  address mapping and does not allow reads.  This
2345bd49e16eSAndy Lutomirski		  configuration is recommended when userspace might use the
2346bd49e16eSAndy Lutomirski		  legacy vsyscall area but support for legacy binary
2347bd49e16eSAndy Lutomirski		  instrumentation of legacy code is not needed.  It mitigates
2348bd49e16eSAndy Lutomirski		  certain uses of the vsyscall area as an ASLR-bypassing
2349bd49e16eSAndy Lutomirski		  buffer.
23503dc33bd3SKees Cook
23513dc33bd3SKees Cook	config LEGACY_VSYSCALL_NONE
23523dc33bd3SKees Cook		bool "None"
23533dc33bd3SKees Cook		help
23543dc33bd3SKees Cook		  There will be no vsyscall mapping at all. This will
23553dc33bd3SKees Cook		  eliminate any risk of ASLR bypass due to the vsyscall
23563dc33bd3SKees Cook		  fixed address mapping. Attempts to use the vsyscalls
23573dc33bd3SKees Cook		  will be reported to dmesg, so that either old or
23583dc33bd3SKees Cook		  malicious userspace programs can be identified.
23593dc33bd3SKees Cook
23603dc33bd3SKees Cookendchoice
23613dc33bd3SKees Cook
2362516cbf37STim Birdconfig CMDLINE_BOOL
2363516cbf37STim Bird	bool "Built-in kernel command line"
2364a7f7f624SMasahiro Yamada	help
2365516cbf37STim Bird	  Allow for specifying boot arguments to the kernel at
2366516cbf37STim Bird	  build time.  On some systems (e.g. embedded ones), it is
2367516cbf37STim Bird	  necessary or convenient to provide some or all of the
2368516cbf37STim Bird	  kernel boot arguments with the kernel itself (that is,
2369516cbf37STim Bird	  to not rely on the boot loader to provide them.)
2370516cbf37STim Bird
2371516cbf37STim Bird	  To compile command line arguments into the kernel,
2372516cbf37STim Bird	  set this option to 'Y', then fill in the
237369711ca1SSébastien Hinderer	  boot arguments in CONFIG_CMDLINE.
2374516cbf37STim Bird
2375516cbf37STim Bird	  Systems with fully functional boot loaders (i.e. non-embedded)
2376516cbf37STim Bird	  should leave this option set to 'N'.
2377516cbf37STim Bird
2378516cbf37STim Birdconfig CMDLINE
2379516cbf37STim Bird	string "Built-in kernel command string"
2380516cbf37STim Bird	depends on CMDLINE_BOOL
2381516cbf37STim Bird	default ""
2382a7f7f624SMasahiro Yamada	help
2383516cbf37STim Bird	  Enter arguments here that should be compiled into the kernel
2384516cbf37STim Bird	  image and used at boot time.  If the boot loader provides a
2385516cbf37STim Bird	  command line at boot time, it is appended to this string to
2386516cbf37STim Bird	  form the full kernel command line, when the system boots.
2387516cbf37STim Bird
2388516cbf37STim Bird	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2389516cbf37STim Bird	  change this behavior.
2390516cbf37STim Bird
2391516cbf37STim Bird	  In most cases, the command line (whether built-in or provided
2392516cbf37STim Bird	  by the boot loader) should specify the device for the root
2393516cbf37STim Bird	  file system.
2394516cbf37STim Bird
2395516cbf37STim Birdconfig CMDLINE_OVERRIDE
2396516cbf37STim Bird	bool "Built-in command line overrides boot loader arguments"
2397645e6466SAnders Roxell	depends on CMDLINE_BOOL && CMDLINE != ""
2398a7f7f624SMasahiro Yamada	help
2399516cbf37STim Bird	  Set this option to 'Y' to have the kernel ignore the boot loader
2400516cbf37STim Bird	  command line, and use ONLY the built-in command line.
2401516cbf37STim Bird
2402516cbf37STim Bird	  This is used to work around broken boot loaders.  This should
2403516cbf37STim Bird	  be set to 'N' under normal conditions.
2404516cbf37STim Bird
2405a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL
2406a5b9e5a2SAndy Lutomirski	bool "Enable the LDT (local descriptor table)" if EXPERT
2407a5b9e5a2SAndy Lutomirski	default y
2408a7f7f624SMasahiro Yamada	help
2409a5b9e5a2SAndy Lutomirski	  Linux can allow user programs to install a per-process x86
2410a5b9e5a2SAndy Lutomirski	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2411a5b9e5a2SAndy Lutomirski	  call.  This is required to run 16-bit or segmented code such as
2412a5b9e5a2SAndy Lutomirski	  DOSEMU or some Wine programs.  It is also used by some very old
2413a5b9e5a2SAndy Lutomirski	  threading libraries.
2414a5b9e5a2SAndy Lutomirski
2415a5b9e5a2SAndy Lutomirski	  Enabling this feature adds a small amount of overhead to
2416a5b9e5a2SAndy Lutomirski	  context switches and increases the low-level kernel attack
2417a5b9e5a2SAndy Lutomirski	  surface.  Disabling it removes the modify_ldt(2) system call.
2418a5b9e5a2SAndy Lutomirski
2419a5b9e5a2SAndy Lutomirski	  Saying 'N' here may make sense for embedded or server kernels.
2420a5b9e5a2SAndy Lutomirski
2421b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig"
2422b700e7f0SSeth Jennings
2423506f1d07SSam Ravnborgendmenu
2424506f1d07SSam Ravnborg
24253072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES
24263072e413SMichal Hocko	def_bool y
24273072e413SMichal Hocko	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
24283072e413SMichal Hocko
2429506f1d07SSam Ravnborgconfig ARCH_ENABLE_MEMORY_HOTPLUG
2430506f1d07SSam Ravnborg	def_bool y
2431506f1d07SSam Ravnborg	depends on X86_64 || (X86_32 && HIGHMEM)
2432506f1d07SSam Ravnborg
243335551053SGary Hadeconfig ARCH_ENABLE_MEMORY_HOTREMOVE
243435551053SGary Hade	def_bool y
243535551053SGary Hade	depends on MEMORY_HOTPLUG
243635551053SGary Hade
2437e534c7c5SLee Schermerhornconfig USE_PERCPU_NUMA_NODE_ID
2438645a7919STejun Heo	def_bool y
2439e534c7c5SLee Schermerhorn	depends on NUMA
2440e534c7c5SLee Schermerhorn
24419491846fSKirill A. Shutemovconfig ARCH_ENABLE_SPLIT_PMD_PTLOCK
24429491846fSKirill A. Shutemov	def_bool y
24439491846fSKirill A. Shutemov	depends on X86_64 || X86_PAE
24449491846fSKirill A. Shutemov
2445c177c81eSNaoya Horiguchiconfig ARCH_ENABLE_HUGEPAGE_MIGRATION
2446c177c81eSNaoya Horiguchi	def_bool y
2447c177c81eSNaoya Horiguchi	depends on X86_64 && HUGETLB_PAGE && MIGRATION
2448c177c81eSNaoya Horiguchi
24499c670ea3SNaoya Horiguchiconfig ARCH_ENABLE_THP_MIGRATION
24509c670ea3SNaoya Horiguchi	def_bool y
24519c670ea3SNaoya Horiguchi	depends on X86_64 && TRANSPARENT_HUGEPAGE
24529c670ea3SNaoya Horiguchi
2453da85f865SBjorn Helgaasmenu "Power management and ACPI options"
2454e279b6c1SSam Ravnborg
2455e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER
24563c2362e6SHarvey Harrison	def_bool y
245744556530SZhimin Gu	depends on HIBERNATION
2458e279b6c1SSam Ravnborg
2459e279b6c1SSam Ravnborgsource "kernel/power/Kconfig"
2460e279b6c1SSam Ravnborg
2461e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig"
2462e279b6c1SSam Ravnborg
2463efafc8b2SFeng Tangsource "drivers/sfi/Kconfig"
2464efafc8b2SFeng Tang
2465a6b68076SAndi Kleenconfig X86_APM_BOOT
24666fc108a0SJan Beulich	def_bool y
2467282e5aabSPaul Bolle	depends on APM
2468a6b68076SAndi Kleen
2469e279b6c1SSam Ravnborgmenuconfig APM
2470e279b6c1SSam Ravnborg	tristate "APM (Advanced Power Management) BIOS support"
2471efefa6f6SIngo Molnar	depends on X86_32 && PM_SLEEP
2472a7f7f624SMasahiro Yamada	help
2473e279b6c1SSam Ravnborg	  APM is a BIOS specification for saving power using several different
2474e279b6c1SSam Ravnborg	  techniques. This is mostly useful for battery powered laptops with
2475e279b6c1SSam Ravnborg	  APM compliant BIOSes. If you say Y here, the system time will be
2476e279b6c1SSam Ravnborg	  reset after a RESUME operation, the /proc/apm device will provide
2477e279b6c1SSam Ravnborg	  battery status information, and user-space programs will receive
2478e279b6c1SSam Ravnborg	  notification of APM "events" (e.g. battery status change).
2479e279b6c1SSam Ravnborg
2480e279b6c1SSam Ravnborg	  If you select "Y" here, you can disable actual use of the APM
2481e279b6c1SSam Ravnborg	  BIOS by passing the "apm=off" option to the kernel at boot time.
2482e279b6c1SSam Ravnborg
2483e279b6c1SSam Ravnborg	  Note that the APM support is almost completely disabled for
2484e279b6c1SSam Ravnborg	  machines with more than one CPU.
2485e279b6c1SSam Ravnborg
2486e279b6c1SSam Ravnborg	  In order to use APM, you will need supporting software. For location
2487151f4e2bSMauro Carvalho Chehab	  and more information, read <file:Documentation/power/apm-acpi.rst>
24882dc98fd3SMichael Witten	  and the Battery Powered Linux mini-HOWTO, available from
2489e279b6c1SSam Ravnborg	  <http://www.tldp.org/docs.html#howto>.
2490e279b6c1SSam Ravnborg
2491e279b6c1SSam Ravnborg	  This driver does not spin down disk drives (see the hdparm(8)
2492e279b6c1SSam Ravnborg	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2493e279b6c1SSam Ravnborg	  VESA-compliant "green" monitors.
2494e279b6c1SSam Ravnborg
2495e279b6c1SSam Ravnborg	  This driver does not support the TI 4000M TravelMate and the ACER
2496e279b6c1SSam Ravnborg	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2497e279b6c1SSam Ravnborg	  desktop machines also don't have compliant BIOSes, and this driver
2498e279b6c1SSam Ravnborg	  may cause those machines to panic during the boot phase.
2499e279b6c1SSam Ravnborg
2500e279b6c1SSam Ravnborg	  Generally, if you don't have a battery in your machine, there isn't
2501e279b6c1SSam Ravnborg	  much point in using this driver and you should say N. If you get
2502e279b6c1SSam Ravnborg	  random kernel OOPSes or reboots that don't seem to be related to
2503e279b6c1SSam Ravnborg	  anything, try disabling/enabling this option (or disabling/enabling
2504e279b6c1SSam Ravnborg	  APM in your BIOS).
2505e279b6c1SSam Ravnborg
2506e279b6c1SSam Ravnborg	  Some other things you should try when experiencing seemingly random,
2507e279b6c1SSam Ravnborg	  "weird" problems:
2508e279b6c1SSam Ravnborg
2509e279b6c1SSam Ravnborg	  1) make sure that you have enough swap space and that it is
2510e279b6c1SSam Ravnborg	  enabled.
2511e279b6c1SSam Ravnborg	  2) pass the "no-hlt" option to the kernel
2512e279b6c1SSam Ravnborg	  3) switch on floating point emulation in the kernel and pass
2513e279b6c1SSam Ravnborg	  the "no387" option to the kernel
2514e279b6c1SSam Ravnborg	  4) pass the "floppy=nodma" option to the kernel
2515e279b6c1SSam Ravnborg	  5) pass the "mem=4M" option to the kernel (thereby disabling
2516e279b6c1SSam Ravnborg	  all but the first 4 MB of RAM)
2517e279b6c1SSam Ravnborg	  6) make sure that the CPU is not over clocked.
2518e279b6c1SSam Ravnborg	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2519e279b6c1SSam Ravnborg	  8) disable the cache from your BIOS settings
2520e279b6c1SSam Ravnborg	  9) install a fan for the video card or exchange video RAM
2521e279b6c1SSam Ravnborg	  10) install a better fan for the CPU
2522e279b6c1SSam Ravnborg	  11) exchange RAM chips
2523e279b6c1SSam Ravnborg	  12) exchange the motherboard.
2524e279b6c1SSam Ravnborg
2525e279b6c1SSam Ravnborg	  To compile this driver as a module, choose M here: the
2526e279b6c1SSam Ravnborg	  module will be called apm.
2527e279b6c1SSam Ravnborg
2528e279b6c1SSam Ravnborgif APM
2529e279b6c1SSam Ravnborg
2530e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND
2531e279b6c1SSam Ravnborg	bool "Ignore USER SUSPEND"
2532a7f7f624SMasahiro Yamada	help
2533e279b6c1SSam Ravnborg	  This option will ignore USER SUSPEND requests. On machines with a
2534e279b6c1SSam Ravnborg	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2535e279b6c1SSam Ravnborg	  series notebooks, it is necessary to say Y because of a BIOS bug.
2536e279b6c1SSam Ravnborg
2537e279b6c1SSam Ravnborgconfig APM_DO_ENABLE
2538e279b6c1SSam Ravnborg	bool "Enable PM at boot time"
2539a7f7f624SMasahiro Yamada	help
2540e279b6c1SSam Ravnborg	  Enable APM features at boot time. From page 36 of the APM BIOS
2541e279b6c1SSam Ravnborg	  specification: "When disabled, the APM BIOS does not automatically
2542e279b6c1SSam Ravnborg	  power manage devices, enter the Standby State, enter the Suspend
2543e279b6c1SSam Ravnborg	  State, or take power saving steps in response to CPU Idle calls."
2544e279b6c1SSam Ravnborg	  This driver will make CPU Idle calls when Linux is idle (unless this
2545e279b6c1SSam Ravnborg	  feature is turned off -- see "Do CPU IDLE calls", below). This
2546e279b6c1SSam Ravnborg	  should always save battery power, but more complicated APM features
2547e279b6c1SSam Ravnborg	  will be dependent on your BIOS implementation. You may need to turn
2548e279b6c1SSam Ravnborg	  this option off if your computer hangs at boot time when using APM
2549e279b6c1SSam Ravnborg	  support, or if it beeps continuously instead of suspending. Turn
2550e279b6c1SSam Ravnborg	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2551e279b6c1SSam Ravnborg	  T400CDT. This is off by default since most machines do fine without
2552e279b6c1SSam Ravnborg	  this feature.
2553e279b6c1SSam Ravnborg
2554e279b6c1SSam Ravnborgconfig APM_CPU_IDLE
2555dd8af076SLen Brown	depends on CPU_IDLE
2556e279b6c1SSam Ravnborg	bool "Make CPU Idle calls when idle"
2557a7f7f624SMasahiro Yamada	help
2558e279b6c1SSam Ravnborg	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2559e279b6c1SSam Ravnborg	  On some machines, this can activate improved power savings, such as
2560e279b6c1SSam Ravnborg	  a slowed CPU clock rate, when the machine is idle. These idle calls
2561e279b6c1SSam Ravnborg	  are made after the idle loop has run for some length of time (e.g.,
2562e279b6c1SSam Ravnborg	  333 mS). On some machines, this will cause a hang at boot time or
2563e279b6c1SSam Ravnborg	  whenever the CPU becomes idle. (On machines with more than one CPU,
2564e279b6c1SSam Ravnborg	  this option does nothing.)
2565e279b6c1SSam Ravnborg
2566e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK
2567e279b6c1SSam Ravnborg	bool "Enable console blanking using APM"
2568a7f7f624SMasahiro Yamada	help
2569e279b6c1SSam Ravnborg	  Enable console blanking using the APM. Some laptops can use this to
2570e279b6c1SSam Ravnborg	  turn off the LCD backlight when the screen blanker of the Linux
2571e279b6c1SSam Ravnborg	  virtual console blanks the screen. Note that this is only used by
2572e279b6c1SSam Ravnborg	  the virtual console screen blanker, and won't turn off the backlight
2573e279b6c1SSam Ravnborg	  when using the X Window system. This also doesn't have anything to
2574e279b6c1SSam Ravnborg	  do with your VESA-compliant power-saving monitor. Further, this
2575e279b6c1SSam Ravnborg	  option doesn't work for all laptops -- it might not turn off your
2576e279b6c1SSam Ravnborg	  backlight at all, or it might print a lot of errors to the console,
2577e279b6c1SSam Ravnborg	  especially if you are using gpm.
2578e279b6c1SSam Ravnborg
2579e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS
2580e279b6c1SSam Ravnborg	bool "Allow interrupts during APM BIOS calls"
2581a7f7f624SMasahiro Yamada	help
2582e279b6c1SSam Ravnborg	  Normally we disable external interrupts while we are making calls to
2583e279b6c1SSam Ravnborg	  the APM BIOS as a measure to lessen the effects of a badly behaving
2584e279b6c1SSam Ravnborg	  BIOS implementation.  The BIOS should reenable interrupts if it
2585e279b6c1SSam Ravnborg	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2586e279b6c1SSam Ravnborg	  many of the newer IBM Thinkpads.  If you experience hangs when you
2587e279b6c1SSam Ravnborg	  suspend, try setting this to Y.  Otherwise, say N.
2588e279b6c1SSam Ravnborg
2589e279b6c1SSam Ravnborgendif # APM
2590e279b6c1SSam Ravnborg
2591bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig"
2592e279b6c1SSam Ravnborg
2593e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig"
2594e279b6c1SSam Ravnborg
259527471fdbSAndy Henroidsource "drivers/idle/Kconfig"
259627471fdbSAndy Henroid
2597e279b6c1SSam Ravnborgendmenu
2598e279b6c1SSam Ravnborg
2599e279b6c1SSam Ravnborg
2600e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)"
2601e279b6c1SSam Ravnborg
2602e279b6c1SSam Ravnborgchoice
2603e279b6c1SSam Ravnborg	prompt "PCI access mode"
2604efefa6f6SIngo Molnar	depends on X86_32 && PCI
2605e279b6c1SSam Ravnborg	default PCI_GOANY
2606a7f7f624SMasahiro Yamada	help
2607e279b6c1SSam Ravnborg	  On PCI systems, the BIOS can be used to detect the PCI devices and
2608e279b6c1SSam Ravnborg	  determine their configuration. However, some old PCI motherboards
2609e279b6c1SSam Ravnborg	  have BIOS bugs and may crash if this is done. Also, some embedded
2610e279b6c1SSam Ravnborg	  PCI-based systems don't have any BIOS at all. Linux can also try to
2611e279b6c1SSam Ravnborg	  detect the PCI hardware directly without using the BIOS.
2612e279b6c1SSam Ravnborg
2613e279b6c1SSam Ravnborg	  With this option, you can specify how Linux should detect the
2614e279b6c1SSam Ravnborg	  PCI devices. If you choose "BIOS", the BIOS will be used,
2615e279b6c1SSam Ravnborg	  if you choose "Direct", the BIOS won't be used, and if you
2616e279b6c1SSam Ravnborg	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2617e279b6c1SSam Ravnborg	  If you choose "Any", the kernel will try MMCONFIG, then the
2618e279b6c1SSam Ravnborg	  direct access method and falls back to the BIOS if that doesn't
2619e279b6c1SSam Ravnborg	  work. If unsure, go with the default, which is "Any".
2620e279b6c1SSam Ravnborg
2621e279b6c1SSam Ravnborgconfig PCI_GOBIOS
2622e279b6c1SSam Ravnborg	bool "BIOS"
2623e279b6c1SSam Ravnborg
2624e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG
2625e279b6c1SSam Ravnborg	bool "MMConfig"
2626e279b6c1SSam Ravnborg
2627e279b6c1SSam Ravnborgconfig PCI_GODIRECT
2628e279b6c1SSam Ravnborg	bool "Direct"
2629e279b6c1SSam Ravnborg
26303ef0e1f8SAndres Salomonconfig PCI_GOOLPC
263176fb6570SDaniel Drake	bool "OLPC XO-1"
26323ef0e1f8SAndres Salomon	depends on OLPC
26333ef0e1f8SAndres Salomon
26342bdd1b03SAndres Salomonconfig PCI_GOANY
26352bdd1b03SAndres Salomon	bool "Any"
26362bdd1b03SAndres Salomon
2637e279b6c1SSam Ravnborgendchoice
2638e279b6c1SSam Ravnborg
2639e279b6c1SSam Ravnborgconfig PCI_BIOS
26403c2362e6SHarvey Harrison	def_bool y
2641efefa6f6SIngo Molnar	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2642e279b6c1SSam Ravnborg
2643e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2644e279b6c1SSam Ravnborgconfig PCI_DIRECT
26453c2362e6SHarvey Harrison	def_bool y
26460aba496fSShaohua Li	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2647e279b6c1SSam Ravnborg
2648e279b6c1SSam Ravnborgconfig PCI_MMCONFIG
2649b45c9f36SJan Kiszka	bool "Support mmconfig PCI config space access" if X86_64
2650b45c9f36SJan Kiszka	default y
26518364e1f8SJan Kiszka	depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2652b45c9f36SJan Kiszka	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2653e279b6c1SSam Ravnborg
26543ef0e1f8SAndres Salomonconfig PCI_OLPC
26552bdd1b03SAndres Salomon	def_bool y
26562bdd1b03SAndres Salomon	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
26573ef0e1f8SAndres Salomon
2658b5401a96SAlex Nixonconfig PCI_XEN
2659b5401a96SAlex Nixon	def_bool y
2660b5401a96SAlex Nixon	depends on PCI && XEN
2661b5401a96SAlex Nixon	select SWIOTLB_XEN
2662b5401a96SAlex Nixon
26638364e1f8SJan Kiszkaconfig MMCONF_FAM10H
26648364e1f8SJan Kiszka	def_bool y
26658364e1f8SJan Kiszka	depends on X86_64 && PCI_MMCONFIG && ACPI
2666e279b6c1SSam Ravnborg
26673f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK
26686a108a14SDavid Rientjes	bool "Read CNB20LE Host Bridge Windows" if EXPERT
26696ea30386SKees Cook	depends on PCI
26703f6ea84aSIra W. Snyder	help
26713f6ea84aSIra W. Snyder	  Read the PCI windows out of the CNB20LE host bridge. This allows
26723f6ea84aSIra W. Snyder	  PCI hotplug to work on systems with the CNB20LE chipset which do
26733f6ea84aSIra W. Snyder	  not have ACPI.
26743f6ea84aSIra W. Snyder
267564a5fed6SBjorn Helgaas	  There's no public spec for this chipset, and this functionality
267664a5fed6SBjorn Helgaas	  is known to be incomplete.
267764a5fed6SBjorn Helgaas
267864a5fed6SBjorn Helgaas	  You should say N unless you know you need this.
267964a5fed6SBjorn Helgaas
26803a495511SWilliam Breathitt Grayconfig ISA_BUS
268117a2a129SWilliam Breathitt Gray	bool "ISA bus support on modern systems" if EXPERT
26823a495511SWilliam Breathitt Gray	help
268317a2a129SWilliam Breathitt Gray	  Expose ISA bus device drivers and options available for selection and
268417a2a129SWilliam Breathitt Gray	  configuration. Enable this option if your target machine has an ISA
268517a2a129SWilliam Breathitt Gray	  bus. ISA is an older system, displaced by PCI and newer bus
268617a2a129SWilliam Breathitt Gray	  architectures -- if your target machine is modern, it probably does
268717a2a129SWilliam Breathitt Gray	  not have an ISA bus.
26883a495511SWilliam Breathitt Gray
26893a495511SWilliam Breathitt Gray	  If unsure, say N.
26903a495511SWilliam Breathitt Gray
26911c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA.
2692e279b6c1SSam Ravnborgconfig ISA_DMA_API
26931c00f016SDavid Rientjes	bool "ISA-style DMA support" if (X86_64 && EXPERT)
26941c00f016SDavid Rientjes	default y
26951c00f016SDavid Rientjes	help
26961c00f016SDavid Rientjes	  Enables ISA-style DMA support for devices requiring such controllers.
26971c00f016SDavid Rientjes	  If unsure, say Y.
2698e279b6c1SSam Ravnborg
269951e68d05SLinus Torvaldsif X86_32
270051e68d05SLinus Torvalds
2701e279b6c1SSam Ravnborgconfig ISA
2702e279b6c1SSam Ravnborg	bool "ISA support"
2703a7f7f624SMasahiro Yamada	help
2704e279b6c1SSam Ravnborg	  Find out whether you have ISA slots on your motherboard.  ISA is the
2705e279b6c1SSam Ravnborg	  name of a bus system, i.e. the way the CPU talks to the other stuff
2706e279b6c1SSam Ravnborg	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2707e279b6c1SSam Ravnborg	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2708e279b6c1SSam Ravnborg	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2709e279b6c1SSam Ravnborg
2710e279b6c1SSam Ravnborgconfig SCx200
2711e279b6c1SSam Ravnborg	tristate "NatSemi SCx200 support"
2712a7f7f624SMasahiro Yamada	help
2713e279b6c1SSam Ravnborg	  This provides basic support for National Semiconductor's
2714e279b6c1SSam Ravnborg	  (now AMD's) Geode processors.  The driver probes for the
2715e279b6c1SSam Ravnborg	  PCI-IDs of several on-chip devices, so its a good dependency
2716e279b6c1SSam Ravnborg	  for other scx200_* drivers.
2717e279b6c1SSam Ravnborg
2718e279b6c1SSam Ravnborg	  If compiled as a module, the driver is named scx200.
2719e279b6c1SSam Ravnborg
2720e279b6c1SSam Ravnborgconfig SCx200HR_TIMER
2721e279b6c1SSam Ravnborg	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2722592913ecSJohn Stultz	depends on SCx200
2723e279b6c1SSam Ravnborg	default y
2724a7f7f624SMasahiro Yamada	help
2725e279b6c1SSam Ravnborg	  This driver provides a clocksource built upon the on-chip
2726e279b6c1SSam Ravnborg	  27MHz high-resolution timer.  Its also a workaround for
2727e279b6c1SSam Ravnborg	  NSC Geode SC-1100's buggy TSC, which loses time when the
2728e279b6c1SSam Ravnborg	  processor goes idle (as is done by the scheduler).  The
2729e279b6c1SSam Ravnborg	  other workaround is idle=poll boot option.
2730e279b6c1SSam Ravnborg
27313ef0e1f8SAndres Salomonconfig OLPC
27323ef0e1f8SAndres Salomon	bool "One Laptop Per Child support"
273354008979SThomas Gleixner	depends on !X86_PAE
27343c554946SAndres Salomon	select GPIOLIB
2735dc3119e7SThomas Gleixner	select OF
273645bb1674SDaniel Drake	select OF_PROMTREE
2737b4e51854SGrant Likely	select IRQ_DOMAIN
27380c3d931bSLubomir Rintel	select OLPC_EC
2739a7f7f624SMasahiro Yamada	help
27403ef0e1f8SAndres Salomon	  Add support for detecting the unique features of the OLPC
27413ef0e1f8SAndres Salomon	  XO hardware.
27423ef0e1f8SAndres Salomon
2743a3128588SDaniel Drakeconfig OLPC_XO1_PM
2744a3128588SDaniel Drake	bool "OLPC XO-1 Power Management"
2745fa112cf1SBorislav Petkov	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2746a7f7f624SMasahiro Yamada	help
274797c4cb71SDaniel Drake	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2748bf1ebf00SDaniel Drake
2749cfee9597SDaniel Drakeconfig OLPC_XO1_RTC
2750cfee9597SDaniel Drake	bool "OLPC XO-1 Real Time Clock"
2751cfee9597SDaniel Drake	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2752a7f7f624SMasahiro Yamada	help
2753cfee9597SDaniel Drake	  Add support for the XO-1 real time clock, which can be used as a
2754cfee9597SDaniel Drake	  programmable wakeup source.
2755cfee9597SDaniel Drake
27567feda8e9SDaniel Drakeconfig OLPC_XO1_SCI
27577feda8e9SDaniel Drake	bool "OLPC XO-1 SCI extras"
275892e830f2SArnd Bergmann	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2759ed8e47feSRandy Dunlap	depends on INPUT=y
2760d8d01a63SDaniel Drake	select POWER_SUPPLY
2761a7f7f624SMasahiro Yamada	help
27627feda8e9SDaniel Drake	  Add support for SCI-based features of the OLPC XO-1 laptop:
27637bc74b3dSDaniel Drake	   - EC-driven system wakeups
27647feda8e9SDaniel Drake	   - Power button
27657bc74b3dSDaniel Drake	   - Ebook switch
27662cf2baeaSDaniel Drake	   - Lid switch
2767e1040ac6SDaniel Drake	   - AC adapter status updates
2768e1040ac6SDaniel Drake	   - Battery status updates
27697feda8e9SDaniel Drake
2770a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI
2771a0f30f59SDaniel Drake	bool "OLPC XO-1.5 SCI extras"
2772d8d01a63SDaniel Drake	depends on OLPC && ACPI
2773d8d01a63SDaniel Drake	select POWER_SUPPLY
2774a7f7f624SMasahiro Yamada	help
2775a0f30f59SDaniel Drake	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2776a0f30f59SDaniel Drake	   - EC-driven system wakeups
2777a0f30f59SDaniel Drake	   - AC adapter status updates
2778a0f30f59SDaniel Drake	   - Battery status updates
2779e279b6c1SSam Ravnborg
2780d4f3e350SEd Wildgooseconfig ALIX
2781d4f3e350SEd Wildgoose	bool "PCEngines ALIX System Support (LED setup)"
2782d4f3e350SEd Wildgoose	select GPIOLIB
2783a7f7f624SMasahiro Yamada	help
2784d4f3e350SEd Wildgoose	  This option enables system support for the PCEngines ALIX.
2785d4f3e350SEd Wildgoose	  At present this just sets up LEDs for GPIO control on
2786d4f3e350SEd Wildgoose	  ALIX2/3/6 boards.  However, other system specific setup should
2787d4f3e350SEd Wildgoose	  get added here.
2788d4f3e350SEd Wildgoose
2789d4f3e350SEd Wildgoose	  Note: You must still enable the drivers for GPIO and LED support
2790d4f3e350SEd Wildgoose	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2791d4f3e350SEd Wildgoose
2792d4f3e350SEd Wildgoose	  Note: You have to set alix.force=1 for boards with Award BIOS.
2793d4f3e350SEd Wildgoose
2794da4e3302SPhilip Prindevilleconfig NET5501
2795da4e3302SPhilip Prindeville	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2796da4e3302SPhilip Prindeville	select GPIOLIB
2797a7f7f624SMasahiro Yamada	help
2798da4e3302SPhilip Prindeville	  This option enables system support for the Soekris Engineering net5501.
2799da4e3302SPhilip Prindeville
28003197059aSPhilip A. Prindevilleconfig GEOS
28013197059aSPhilip A. Prindeville	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
28023197059aSPhilip A. Prindeville	select GPIOLIB
28033197059aSPhilip A. Prindeville	depends on DMI
2804a7f7f624SMasahiro Yamada	help
28053197059aSPhilip A. Prindeville	  This option enables system support for the Traverse Technologies GEOS.
28063197059aSPhilip A. Prindeville
28077d029125SVivien Didelotconfig TS5500
28087d029125SVivien Didelot	bool "Technologic Systems TS-5500 platform support"
28097d029125SVivien Didelot	depends on MELAN
28107d029125SVivien Didelot	select CHECK_SIGNATURE
28117d029125SVivien Didelot	select NEW_LEDS
28127d029125SVivien Didelot	select LEDS_CLASS
2813a7f7f624SMasahiro Yamada	help
28147d029125SVivien Didelot	  This option enables system support for the Technologic Systems TS-5500.
28157d029125SVivien Didelot
2816e279b6c1SSam Ravnborgendif # X86_32
2817e279b6c1SSam Ravnborg
281823ac4ae8SAndreas Herrmannconfig AMD_NB
2819e279b6c1SSam Ravnborg	def_bool y
28200e152cd7SBorislav Petkov	depends on CPU_SUP_AMD && PCI
2821e279b6c1SSam Ravnborg
2822e3263ab3SDavid Herrmannconfig X86_SYSFB
2823e3263ab3SDavid Herrmann	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2824e3263ab3SDavid Herrmann	help
2825e3263ab3SDavid Herrmann	  Firmwares often provide initial graphics framebuffers so the BIOS,
2826e3263ab3SDavid Herrmann	  bootloader or kernel can show basic video-output during boot for
2827e3263ab3SDavid Herrmann	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2828e3263ab3SDavid Herrmann	  Extensions and EFI-framebuffers for this, which are mostly limited
2829e3263ab3SDavid Herrmann	  to x86.
2830e3263ab3SDavid Herrmann	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2831e3263ab3SDavid Herrmann	  framebuffers so the new generic system-framebuffer drivers can be
2832e3263ab3SDavid Herrmann	  used on x86. If the framebuffer is not compatible with the generic
2833e3a5dc08SNikolas Nyby	  modes, it is advertised as fallback platform framebuffer so legacy
2834e3263ab3SDavid Herrmann	  drivers like efifb, vesafb and uvesafb can pick it up.
2835e3263ab3SDavid Herrmann	  If this option is not selected, all system framebuffers are always
2836e3263ab3SDavid Herrmann	  marked as fallback platform framebuffers as usual.
2837e3263ab3SDavid Herrmann
2838e3263ab3SDavid Herrmann	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2839e3263ab3SDavid Herrmann	  not be able to pick up generic system framebuffers if this option
2840e3263ab3SDavid Herrmann	  is selected. You are highly encouraged to enable simplefb as
2841e3263ab3SDavid Herrmann	  replacement if you select this option. simplefb can correctly deal
2842e3263ab3SDavid Herrmann	  with generic system framebuffers. But you should still keep vesafb
2843e3263ab3SDavid Herrmann	  and others enabled as fallback if a system framebuffer is
2844e3263ab3SDavid Herrmann	  incompatible with simplefb.
2845e3263ab3SDavid Herrmann
2846e3263ab3SDavid Herrmann	  If unsure, say Y.
2847e3263ab3SDavid Herrmann
2848e279b6c1SSam Ravnborgendmenu
2849e279b6c1SSam Ravnborg
2850e279b6c1SSam Ravnborg
28511572497cSChristoph Hellwigmenu "Binary Emulations"
2852e279b6c1SSam Ravnborg
2853e279b6c1SSam Ravnborgconfig IA32_EMULATION
2854e279b6c1SSam Ravnborg	bool "IA32 Emulation"
2855e279b6c1SSam Ravnborg	depends on X86_64
285639f88911SIngo Molnar	select ARCH_WANT_OLD_COMPAT_IPC
2857d1603990SRandy Dunlap	select BINFMT_ELF
2858a97f52e6SRoland McGrath	select COMPAT_BINFMT_ELF
285939f88911SIngo Molnar	select COMPAT_OLD_SIGACTION
2860a7f7f624SMasahiro Yamada	help
28615fd92e65SH. J. Lu	  Include code to run legacy 32-bit programs under a
28625fd92e65SH. J. Lu	  64-bit kernel. You should likely turn this on, unless you're
28635fd92e65SH. J. Lu	  100% sure that you don't have any 32-bit programs left.
2864e279b6c1SSam Ravnborg
2865e279b6c1SSam Ravnborgconfig IA32_AOUT
2866e279b6c1SSam Ravnborg	tristate "IA32 a.out support"
28676b213e1bSDavid Woodhouse	depends on IA32_EMULATION
2868eac61655SBorislav Petkov	depends on BROKEN
2869a7f7f624SMasahiro Yamada	help
2870e279b6c1SSam Ravnborg	  Support old a.out binaries in the 32bit emulation.
2871e279b6c1SSam Ravnborg
28720bf62763SH. Peter Anvinconfig X86_X32
28736ea30386SKees Cook	bool "x32 ABI for 64-bit mode"
28749b54050bSBrian Gerst	depends on X86_64
2875a7f7f624SMasahiro Yamada	help
28765fd92e65SH. J. Lu	  Include code to run binaries for the x32 native 32-bit ABI
28775fd92e65SH. J. Lu	  for 64-bit processors.  An x32 process gets access to the
28785fd92e65SH. J. Lu	  full 64-bit register file and wide data path while leaving
28795fd92e65SH. J. Lu	  pointers at 32 bits for smaller memory footprint.
28805fd92e65SH. J. Lu
28815fd92e65SH. J. Lu	  You will need a recent binutils (2.22 or later) with
28825fd92e65SH. J. Lu	  elf32_x86_64 support enabled to compile a kernel with this
28835fd92e65SH. J. Lu	  option set.
28845fd92e65SH. J. Lu
2885953fee1dSIngo Molnarconfig COMPAT_32
2886953fee1dSIngo Molnar	def_bool y
2887953fee1dSIngo Molnar	depends on IA32_EMULATION || X86_32
2888953fee1dSIngo Molnar	select HAVE_UID16
2889953fee1dSIngo Molnar	select OLD_SIGSUSPEND3
2890953fee1dSIngo Molnar
2891e279b6c1SSam Ravnborgconfig COMPAT
28923c2362e6SHarvey Harrison	def_bool y
28930bf62763SH. Peter Anvin	depends on IA32_EMULATION || X86_X32
2894e279b6c1SSam Ravnborg
28953120e25eSJan Beulichif COMPAT
2896e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT
28973120e25eSJan Beulich	def_bool y
2898e279b6c1SSam Ravnborg
2899e279b6c1SSam Ravnborgconfig SYSVIPC_COMPAT
29003c2362e6SHarvey Harrison	def_bool y
29013120e25eSJan Beulich	depends on SYSVIPC
29023120e25eSJan Beulichendif
2903ee009e4aSDavid Howells
2904e279b6c1SSam Ravnborgendmenu
2905e279b6c1SSam Ravnborg
2906e279b6c1SSam Ravnborg
2907e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP
2908e5beae16SKeith Packard	def_bool y
2909e5beae16SKeith Packard	depends on X86_32
2910e5beae16SKeith Packard
2911e279b6c1SSam Ravnborgsource "drivers/firmware/Kconfig"
2912e279b6c1SSam Ravnborg
2913edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig"
29145e8ebd84SJason A. Donenfeld
29155e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler"
2916