xref: /linux/arch/x86/Kconfig (revision bf00745e7791fe2ba7941aeead8528075a158bbe)
1b2441318SGreg Kroah-Hartman# SPDX-License-Identifier: GPL-2.0
2daa93fabSSam Ravnborg# Select 32 or 64 bit
3daa93fabSSam Ravnborgconfig 64BIT
4104daea1SMasahiro Yamada	bool "64-bit kernel" if "$(ARCH)" = "x86"
5104daea1SMasahiro Yamada	default "$(ARCH)" != "i386"
6a7f7f624SMasahiro Yamada	help
7daa93fabSSam Ravnborg	  Say yes to build a 64-bit kernel - formerly known as x86_64
8daa93fabSSam Ravnborg	  Say no to build a 32-bit kernel - formerly known as i386
9daa93fabSSam Ravnborg
10daa93fabSSam Ravnborgconfig X86_32
113120e25eSJan Beulich	def_bool y
123120e25eSJan Beulich	depends on !64BIT
13341c787eSIngo Molnar	# Options that are inherently 32-bit kernel only:
14341c787eSIngo Molnar	select ARCH_WANT_IPC_PARSE_VERSION
15341c787eSIngo Molnar	select CLKSRC_I8253
16341c787eSIngo Molnar	select CLONE_BACKWARDS
17157e118bSThomas Gleixner	select GENERIC_VDSO_32
18117ed454SThomas Gleixner	select HAVE_DEBUG_STACKOVERFLOW
19157e118bSThomas Gleixner	select KMAP_LOCAL
20341c787eSIngo Molnar	select MODULES_USE_ELF_REL
21341c787eSIngo Molnar	select OLD_SIGACTION
222ca408d9SBrian Gerst	select ARCH_SPLIT_ARG64
23daa93fabSSam Ravnborg
24daa93fabSSam Ravnborgconfig X86_64
253120e25eSJan Beulich	def_bool y
263120e25eSJan Beulich	depends on 64BIT
27d94e0685SIngo Molnar	# Options that are inherently 64-bit kernel only:
284eb0716eSAlexandre Ghiti	select ARCH_HAS_GIGANTIC_PAGE
29c12d3362SArd Biesheuvel	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30d94e0685SIngo Molnar	select ARCH_USE_CMPXCHG_LOCKREF
31d94e0685SIngo Molnar	select HAVE_ARCH_SOFT_DIRTY
32d94e0685SIngo Molnar	select MODULES_USE_ELF_RELA
33f616ab59SChristoph Hellwig	select NEED_DMA_MAP_STATE
3409230cbcSChristoph Hellwig	select SWIOTLB
357facdc42SAl Viro	select ARCH_HAS_ELFCORE_COMPAT
3663703f37SKefeng Wang	select ZONE_DMA32
371032c0baSSam Ravnborg
38518049d9SSteven Rostedt (VMware)config FORCE_DYNAMIC_FTRACE
39518049d9SSteven Rostedt (VMware)	def_bool y
40518049d9SSteven Rostedt (VMware)	depends on X86_32
41518049d9SSteven Rostedt (VMware)	depends on FUNCTION_TRACER
42518049d9SSteven Rostedt (VMware)	select DYNAMIC_FTRACE
43518049d9SSteven Rostedt (VMware)	help
44518049d9SSteven Rostedt (VMware)	 We keep the static function tracing (!DYNAMIC_FTRACE) around
45518049d9SSteven Rostedt (VMware)	 in order to test the non static function tracing in the
46518049d9SSteven Rostedt (VMware)	 generic code, as other architectures still use it. But we
47518049d9SSteven Rostedt (VMware)	 only need to keep it around for x86_64. No need to keep it
48518049d9SSteven Rostedt (VMware)	 for x86_32. For x86_32, force DYNAMIC_FTRACE.
49d94e0685SIngo Molnar#
50d94e0685SIngo Molnar# Arch settings
51d94e0685SIngo Molnar#
52d94e0685SIngo Molnar# ( Note that options that are marked 'if X86_64' could in principle be
53d94e0685SIngo Molnar#   ported to 32-bit as well. )
54d94e0685SIngo Molnar#
558d5fffb9SSam Ravnborgconfig X86
563c2362e6SHarvey Harrison	def_bool y
57c763ea26SIngo Molnar	#
58c763ea26SIngo Molnar	# Note: keep this list sorted alphabetically
59c763ea26SIngo Molnar	#
606471b825SIngo Molnar	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
616e0a0ea1SGraeme Gregory	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
62942fa985SYury Norov	select ARCH_32BIT_OFF_T			if X86_32
632a21ad57SThomas Gleixner	select ARCH_CLOCKSOURCE_INIT
641f6d3a8fSMasami Hiramatsu	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
651e866974SAnshuman Khandual	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
665c11f00bSDavid Hildenbrand	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
6791024b3cSAnshuman Khandual	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
68cebc774fSAnshuman Khandual	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
691e866974SAnshuman Khandual	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
7091dda51aSAleksey Makarov	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
71c2280be8SAnshuman Khandual	select ARCH_HAS_CACHE_LINE_SIZE
722792d84eSKees Cook	select ARCH_HAS_CURRENT_STACK_POINTER
73fa5b6ec9SLaura Abbott	select ARCH_HAS_DEBUG_VIRTUAL
74399145f9SAnshuman Khandual	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
7521266be9SDan Williams	select ARCH_HAS_DEVMEM_IS_ALLOWED
76b1a57bbfSDouglas Anderson	select ARCH_HAS_EARLY_DEBUG		if KGDB
776471b825SIngo Molnar	select ARCH_HAS_ELF_RANDOMIZE
7872d93104SLinus Torvalds	select ARCH_HAS_FAST_MULTIPLIER
79316d097cSDave Hansen	select ARCH_HAS_FILTER_PGPROT
806974f0c4SDaniel Micay	select ARCH_HAS_FORTIFY_SOURCE
81957e3facSRiku Voipio	select ARCH_HAS_GCOV_PROFILE_ALL
82bece04b5SMarco Elver	select ARCH_HAS_KCOV			if X86_64
830c9c1d56SThiago Jung Bauermann	select ARCH_HAS_MEM_ENCRYPT
8410bcc80eSMathieu Desnoyers	select ARCH_HAS_MEMBARRIER_SYNC_CORE
850ebeea8cSDaniel Borkmann	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
86c763ea26SIngo Molnar	select ARCH_HAS_PMEM_API		if X86_64
8717596731SRobin Murphy	select ARCH_HAS_PTE_DEVMAP		if X86_64
883010a5eaSLaurent Dufour	select ARCH_HAS_PTE_SPECIAL
890aed55afSDan Williams	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
90ec6347bbSDan Williams	select ARCH_HAS_COPY_MC			if X86_64
91d2852a22SDaniel Borkmann	select ARCH_HAS_SET_MEMORY
92d253ca0cSRick Edgecombe	select ARCH_HAS_SET_DIRECT_MAP
93ad21fc4fSLaura Abbott	select ARCH_HAS_STRICT_KERNEL_RWX
94ad21fc4fSLaura Abbott	select ARCH_HAS_STRICT_MODULE_RWX
95ac1ab12aSMathieu Desnoyers	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
9625c619e5SBrian Gerst	select ARCH_HAS_SYSCALL_WRAPPER
97c6d30853SAndrey Ryabinin	select ARCH_HAS_UBSAN_SANITIZE_ALL
987e01ccb4SZong Li	select ARCH_HAS_DEBUG_WX
9963703f37SKefeng Wang	select ARCH_HAS_ZONE_DMA_SET if EXPERT
1006471b825SIngo Molnar	select ARCH_HAVE_NMI_SAFE_CMPXCHG
1016471b825SIngo Molnar	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
10277fbbc81SMark Salter	select ARCH_MIGHT_HAVE_PC_PARPORT
1035e2c18c0SMark Salter	select ARCH_MIGHT_HAVE_PC_SERIO
1043599fe12SThomas Gleixner	select ARCH_STACKWALK
1052c870e61SArnd Bergmann	select ARCH_SUPPORTS_ACPI
1066471b825SIngo Molnar	select ARCH_SUPPORTS_ATOMIC_RMW
1075d6ad668SMike Rapoport	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
108d283d422SPasha Tatashin	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
1096471b825SIngo Molnar	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
11014df3267SThomas Gleixner	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
111583bfd48SNathan Chancellor	select ARCH_SUPPORTS_LTO_CLANG
112583bfd48SNathan Chancellor	select ARCH_SUPPORTS_LTO_CLANG_THIN
1136471b825SIngo Molnar	select ARCH_USE_BUILTIN_BSWAP
114dce44566SAnshuman Khandual	select ARCH_USE_MEMTEST
1156471b825SIngo Molnar	select ARCH_USE_QUEUED_RWLOCKS
1166471b825SIngo Molnar	select ARCH_USE_QUEUED_SPINLOCKS
1172ce0d7f9SMark Brown	select ARCH_USE_SYM_ANNOTATIONS
118ce4a4e56SAndy Lutomirski	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
11981c22041SDaniel Borkmann	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
120c763ea26SIngo Molnar	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
12151c2ee6dSNick Desaulniers	select ARCH_WANTS_NO_INSTR
12207431506SAnshuman Khandual	select ARCH_WANT_GENERAL_HUGETLB
1233876d4a3SAlexandre Ghiti	select ARCH_WANT_HUGE_PMD_SHARE
12459612b24SNathan Chancellor	select ARCH_WANT_LD_ORPHAN_WARN
12538d8b4e6SHuang Ying	select ARCH_WANTS_THP_SWAP		if X86_64
126b5f06f64SBalbir Singh	select ARCH_HAS_PARANOID_L1D_FLUSH
12710916706SShile Zhang	select BUILDTIME_TABLE_SORT
1286471b825SIngo Molnar	select CLKEVT_I8253
1296471b825SIngo Molnar	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
1306471b825SIngo Molnar	select CLOCKSOURCE_WATCHDOG
1316471b825SIngo Molnar	select DCACHE_WORD_ACCESS
1323aac3ebeSThomas Gleixner	select DYNAMIC_SIGFRAME
13345471cd9SLinus Torvalds	select EDAC_ATOMIC_SCRUB
13445471cd9SLinus Torvalds	select EDAC_SUPPORT
1356471b825SIngo Molnar	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
1366471b825SIngo Molnar	select GENERIC_CLOCKEVENTS_MIN_ADJUST
1376471b825SIngo Molnar	select GENERIC_CMOS_UPDATE
1386471b825SIngo Molnar	select GENERIC_CPU_AUTOPROBE
13961dc0f55SThomas Gleixner	select GENERIC_CPU_VULNERABILITIES
1406471b825SIngo Molnar	select GENERIC_EARLY_IOREMAP
14127d6b4d1SThomas Gleixner	select GENERIC_ENTRY
1426471b825SIngo Molnar	select GENERIC_IOMAP
143c7d6c9ddSThomas Gleixner	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
1440fa115daSThomas Gleixner	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
145ad7a929fSThomas Gleixner	select GENERIC_IRQ_MIGRATION		if SMP
1466471b825SIngo Molnar	select GENERIC_IRQ_PROBE
147c201c917SThomas Gleixner	select GENERIC_IRQ_RESERVATION_MODE
1486471b825SIngo Molnar	select GENERIC_IRQ_SHOW
1496471b825SIngo Molnar	select GENERIC_PENDING_IRQ		if SMP
1502ae27137SSteven Price	select GENERIC_PTDUMP
1516471b825SIngo Molnar	select GENERIC_SMP_IDLE_THREAD
1526471b825SIngo Molnar	select GENERIC_TIME_VSYSCALL
1537ac87074SVincenzo Frascino	select GENERIC_GETTIMEOFDAY
154550a77a7SDmitry Safonov	select GENERIC_VDSO_TIME_NS
15539656e83SChristoph Hellwig	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
15617e5888eSHans de Goede	select HARDIRQS_SW_RESEND
1577edaeb68SThomas Gleixner	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
1586471b825SIngo Molnar	select HAVE_ACPI_APEI			if ACPI
1596471b825SIngo Molnar	select HAVE_ACPI_APEI_NMI		if ACPI
1606471b825SIngo Molnar	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
1616471b825SIngo Molnar	select HAVE_ARCH_AUDITSYSCALL
1626471b825SIngo Molnar	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
163eed1fceeSSong Liu	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
1646471b825SIngo Molnar	select HAVE_ARCH_JUMP_LABEL
165b34006c4SArd Biesheuvel	select HAVE_ARCH_JUMP_LABEL_RELATIVE
166d17a1d97SAndrey Ryabinin	select HAVE_ARCH_KASAN			if X86_64
1670609ae01SDaniel Axtens	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
1681dc0da6eSAlexander Potapenko	select HAVE_ARCH_KFENCE
1696471b825SIngo Molnar	select HAVE_ARCH_KGDB
1709e08f57dSDaniel Cashman	select HAVE_ARCH_MMAP_RND_BITS		if MMU
1719e08f57dSDaniel Cashman	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
1721b028f78SDmitry Safonov	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
173271ca788SArd Biesheuvel	select HAVE_ARCH_PREL32_RELOCATIONS
1746471b825SIngo Molnar	select HAVE_ARCH_SECCOMP_FILTER
175f7d83c1cSKees Cook	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
176afaef01cSAlexander Popov	select HAVE_ARCH_STACKLEAK
1776471b825SIngo Molnar	select HAVE_ARCH_TRACEHOOK
1786471b825SIngo Molnar	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
179a00cc7d9SMatthew Wilcox	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
180b64d8d1eSPeter Xu	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
1817677f7fdSAxel Rasmussen	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
182e37e43a4SAndy Lutomirski	select HAVE_ARCH_VMAP_STACK		if X86_64
183fe950f60SKees Cook	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
184c763ea26SIngo Molnar	select HAVE_ARCH_WITHIN_STACK_FRAMES
1852ff2b7ecSMasahiro Yamada	select HAVE_ASM_MODVERSIONS
1866471b825SIngo Molnar	select HAVE_CMPXCHG_DOUBLE
1876471b825SIngo Molnar	select HAVE_CMPXCHG_LOCAL
1886471b825SIngo Molnar	select HAVE_CONTEXT_TRACKING		if X86_64
189d1f250e2SFrederic Weisbecker	select HAVE_CONTEXT_TRACKING_OFFSTACK	if HAVE_CONTEXT_TRACKING
1906471b825SIngo Molnar	select HAVE_C_RECORDMCOUNT
1916dafca97SSami Tolvanen	select HAVE_OBJTOOL_MCOUNT		if STACK_VALIDATION
1924ed308c4SSteven Rostedt (Google)	select HAVE_BUILDTIME_MCOUNT_SORT
1936471b825SIngo Molnar	select HAVE_DEBUG_KMEMLEAK
1949c5a3621SAkinobu Mita	select HAVE_DMA_CONTIGUOUS
195677aa9f7SSteven Rostedt	select HAVE_DYNAMIC_FTRACE
19606aeaaeaSMasami Hiramatsu	select HAVE_DYNAMIC_FTRACE_WITH_REGS
19702a474caSSteven Rostedt (VMware)	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
198562955feSSteven Rostedt (VMware)	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
199c316eb44SHeiko Carstens	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
200503e4510SHeiko Carstens	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
20103f5781bSWang YanQing	select HAVE_EBPF_JIT
20258340a07SJohannes Berg	select HAVE_EFFICIENT_UNALIGNED_ACCESS
2036630a8e5SChristoph Hellwig	select HAVE_EISA
2045f56a5dfSJiri Slaby	select HAVE_EXIT_THREAD
20567a929e0SChristoph Hellwig	select HAVE_FAST_GUP
206644e0e8dSSteven Rostedt (VMware)	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
2076471b825SIngo Molnar	select HAVE_FTRACE_MCOUNT_RECORD
2084a30e4c9SSteven Rostedt (VMware)	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
2096471b825SIngo Molnar	select HAVE_FUNCTION_TRACER
2106b90bd4bSEmese Revfy	select HAVE_GCC_PLUGINS
2110067f129SK.Prasad	select HAVE_HW_BREAKPOINT
2126471b825SIngo Molnar	select HAVE_IOREMAP_PROT
213624db9eaSThomas Gleixner	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
2146471b825SIngo Molnar	select HAVE_IRQ_TIME_ACCOUNTING
2156471b825SIngo Molnar	select HAVE_KERNEL_BZIP2
2166471b825SIngo Molnar	select HAVE_KERNEL_GZIP
2176471b825SIngo Molnar	select HAVE_KERNEL_LZ4
2186471b825SIngo Molnar	select HAVE_KERNEL_LZMA
2196471b825SIngo Molnar	select HAVE_KERNEL_LZO
2206471b825SIngo Molnar	select HAVE_KERNEL_XZ
221fb46d057SNick Terrell	select HAVE_KERNEL_ZSTD
2226471b825SIngo Molnar	select HAVE_KPROBES
2236471b825SIngo Molnar	select HAVE_KPROBES_ON_FTRACE
224540adea3SMasami Hiramatsu	select HAVE_FUNCTION_ERROR_INJECTION
2256471b825SIngo Molnar	select HAVE_KRETPROBES
226f3a112c0SMasami Hiramatsu	select HAVE_RETHOOK
2276471b825SIngo Molnar	select HAVE_KVM
2286471b825SIngo Molnar	select HAVE_LIVEPATCH			if X86_64
2290102752eSFrederic Weisbecker	select HAVE_MIXED_BREAKPOINTS_REGS
230ee9f8fceSJosh Poimboeuf	select HAVE_MOD_ARCH_SPECIFIC
2319f132f7eSJoel Fernandes (Google)	select HAVE_MOVE_PMD
232be37c98dSKalesh Singh	select HAVE_MOVE_PUD
23342a0bb3fSPetr Mladek	select HAVE_NMI
2346471b825SIngo Molnar	select HAVE_OPTPROBES
2356471b825SIngo Molnar	select HAVE_PCSPKR_PLATFORM
2366471b825SIngo Molnar	select HAVE_PERF_EVENTS
237c01d4323SFrederic Weisbecker	select HAVE_PERF_EVENTS_NMI
23892e5aae4SNicholas Piggin	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
239eb01d42aSChristoph Hellwig	select HAVE_PCI
240c5e63197SJiri Olsa	select HAVE_PERF_REGS
241c5ebcedbSJiri Olsa	select HAVE_PERF_USER_STACK_DUMP
242ff2e6d72SPeter Zijlstra	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
24300998085SThomas Gleixner	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
2446471b825SIngo Molnar	select HAVE_REGS_AND_STACK_ACCESS_API
2456415b38bSJiri Slaby	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
2463c88ee19SMasami Hiramatsu	select HAVE_FUNCTION_ARG_ACCESS_API
2477ecd19cfSKefeng Wang	select HAVE_SETUP_PER_CPU_AREA
248cd1a41ceSThomas Gleixner	select HAVE_SOFTIRQ_ON_OWN_STACK
249d148eac0SMasahiro Yamada	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
250c763ea26SIngo Molnar	select HAVE_STACK_VALIDATION		if X86_64
251e6d6c071SJosh Poimboeuf	select HAVE_STATIC_CALL
2521e7e4788SJosh Poimboeuf	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
25399cf983cSMark Rutland	select HAVE_PREEMPT_DYNAMIC_CALL
254d6761b8fSMathieu Desnoyers	select HAVE_RSEQ
2556471b825SIngo Molnar	select HAVE_SYSCALL_TRACEPOINTS
2566471b825SIngo Molnar	select HAVE_UNSTABLE_SCHED_CLOCK
2577c68af6eSAvi Kivity	select HAVE_USER_RETURN_NOTIFIER
2587ac87074SVincenzo Frascino	select HAVE_GENERIC_VDSO
25905736e4aSThomas Gleixner	select HOTPLUG_SMT			if SMP
260c0185808SThomas Gleixner	select IRQ_FORCED_THREADING
2617ecd19cfSKefeng Wang	select NEED_PER_CPU_EMBED_FIRST_CHUNK
2627ecd19cfSKefeng Wang	select NEED_PER_CPU_PAGE_FIRST_CHUNK
26386596f0aSChristoph Hellwig	select NEED_SG_DMA_LENGTH
2642eac9c2dSChristoph Hellwig	select PCI_DOMAINS			if PCI
265625210cfSSinan Kaya	select PCI_LOCKLESS_CONFIG		if PCI
2666471b825SIngo Molnar	select PERF_EVENTS
2673195ef59SPrarit Bhargava	select RTC_LIB
268d6faca40SArnd Bergmann	select RTC_MC146818_LIB
2696471b825SIngo Molnar	select SPARSE_IRQ
27083fe27eaSPranith Kumar	select SRCU
2711e7e4788SJosh Poimboeuf	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
2726471b825SIngo Molnar	select SYSCTL_EXCEPTION_TRACE
27315f4eae7SAndy Lutomirski	select THREAD_INFO_IN_TASK
2744aae683fSMasahiro Yamada	select TRACE_IRQFLAGS_SUPPORT
2756471b825SIngo Molnar	select USER_STACKTRACE_SUPPORT
2766471b825SIngo Molnar	select VIRT_TO_BUS
2773b02a051SIngo Molnar	select HAVE_ARCH_KCSAN			if X86_64
2786471b825SIngo Molnar	select X86_FEATURE_NAMES		if PROC_FS
2790c608dadSAubrey Li	select PROC_PID_ARCH_STATUS		if PROC_FS
28050468e43SJarkko Sakkinen	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
2819e2b4be3SNayna Jain	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
2827d8330a5SBalbir Singh
283ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER
2843120e25eSJan Beulich	def_bool y
2853120e25eSJan Beulich	depends on KPROBES || PERF_EVENTS || UPROBES
286ba7e4d13SIngo Molnar
28751b26adaSLinus Torvaldsconfig OUTPUT_FORMAT
28851b26adaSLinus Torvalds	string
28951b26adaSLinus Torvalds	default "elf32-i386" if X86_32
29051b26adaSLinus Torvalds	default "elf64-x86-64" if X86_64
29151b26adaSLinus Torvalds
2928d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT
2933c2362e6SHarvey Harrison	def_bool y
2948d5fffb9SSam Ravnborg
2958d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT
2963c2362e6SHarvey Harrison	def_bool y
2978d5fffb9SSam Ravnborg
2988d5fffb9SSam Ravnborgconfig MMU
2993c2362e6SHarvey Harrison	def_bool y
3008d5fffb9SSam Ravnborg
3019e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN
3029e08f57dSDaniel Cashman	default 28 if 64BIT
3039e08f57dSDaniel Cashman	default 8
3049e08f57dSDaniel Cashman
3059e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX
3069e08f57dSDaniel Cashman	default 32 if 64BIT
3079e08f57dSDaniel Cashman	default 16
3089e08f57dSDaniel Cashman
3099e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN
3109e08f57dSDaniel Cashman	default 8
3119e08f57dSDaniel Cashman
3129e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX
3139e08f57dSDaniel Cashman	default 16
3149e08f57dSDaniel Cashman
3158d5fffb9SSam Ravnborgconfig SBUS
3168d5fffb9SSam Ravnborg	bool
3178d5fffb9SSam Ravnborg
3188d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA
3193120e25eSJan Beulich	def_bool y
3203120e25eSJan Beulich	depends on ISA_DMA_API
3218d5fffb9SSam Ravnborg
3228d5fffb9SSam Ravnborgconfig GENERIC_BUG
3233c2362e6SHarvey Harrison	def_bool y
3248d5fffb9SSam Ravnborg	depends on BUG
325b93a531eSJan Beulich	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
326b93a531eSJan Beulich
327b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS
328b93a531eSJan Beulich	bool
3298d5fffb9SSam Ravnborg
3308d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC
3313120e25eSJan Beulich	def_bool y
3323120e25eSJan Beulich	depends on ISA_DMA_API
3338d5fffb9SSam Ravnborg
3341032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY
3351032c0baSSam Ravnborg	def_bool y
3361032c0baSSam Ravnborg
3379a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX
3389a0b8415Svenkatesh.pallipadi@intel.com	def_bool y
3398d5fffb9SSam Ravnborg
340801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE
341801e4062SJohannes Berg	def_bool y
342801e4062SJohannes Berg
343d7109fe3SAndy Shevchenkoconfig ARCH_NR_GPIO
344d7109fe3SAndy Shevchenko	int
345d7109fe3SAndy Shevchenko	default 1024 if X86_64
346d7109fe3SAndy Shevchenko	default 512
347d7109fe3SAndy Shevchenko
348f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE
349f4cb5700SJohannes Berg	def_bool y
350f4cb5700SJohannes Berg
3518d5fffb9SSam Ravnborgconfig AUDIT_ARCH
352e0fd24a3SJan Beulich	def_bool y if X86_64
3538d5fffb9SSam Ravnborg
354d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET
355d6f2d75aSAndrey Ryabinin	hex
356d6f2d75aSAndrey Ryabinin	depends on KASAN
357d6f2d75aSAndrey Ryabinin	default 0xdffffc0000000000
358d6f2d75aSAndrey Ryabinin
35969575d38SShane Wangconfig HAVE_INTEL_TXT
36069575d38SShane Wang	def_bool y
3616ea30386SKees Cook	depends on INTEL_IOMMU && ACPI
36269575d38SShane Wang
3636b0c3d44SSam Ravnborgconfig X86_32_SMP
3646b0c3d44SSam Ravnborg	def_bool y
3656b0c3d44SSam Ravnborg	depends on X86_32 && SMP
3666b0c3d44SSam Ravnborg
3676b0c3d44SSam Ravnborgconfig X86_64_SMP
3686b0c3d44SSam Ravnborg	def_bool y
3696b0c3d44SSam Ravnborg	depends on X86_64 && SMP
3706b0c3d44SSam Ravnborg
3712b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES
3722b144498SSrikar Dronamraju	def_bool y
3732b144498SSrikar Dronamraju
374d20642f0SRob Herringconfig FIX_EARLYCON_MEM
375d20642f0SRob Herring	def_bool y
376d20642f0SRob Herring
37794d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK
37894d49eb3SKirill A. Shutemov	bool
37994d49eb3SKirill A. Shutemov
38098233368SKirill A. Shutemovconfig PGTABLE_LEVELS
38198233368SKirill A. Shutemov	int
38277ef56e4SKirill A. Shutemov	default 5 if X86_5LEVEL
38398233368SKirill A. Shutemov	default 4 if X86_64
38498233368SKirill A. Shutemov	default 3 if X86_PAE
38598233368SKirill A. Shutemov	default 2
38698233368SKirill A. Shutemov
3872a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR
3882a61f474SMasahiro Yamada	bool
3892a61f474SMasahiro Yamada	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
3902a61f474SMasahiro Yamada	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
3912a61f474SMasahiro Yamada	help
3922a61f474SMasahiro Yamada	   We have to make sure stack protector is unconditionally disabled if
3933fb0fdb3SAndy Lutomirski	   the compiler produces broken code or if it does not let us control
3943fb0fdb3SAndy Lutomirski	   the segment on 32-bit kernels.
3952a61f474SMasahiro Yamada
396506f1d07SSam Ravnborgmenu "Processor type and features"
397506f1d07SSam Ravnborg
398506f1d07SSam Ravnborgconfig SMP
399506f1d07SSam Ravnborg	bool "Symmetric multi-processing support"
400a7f7f624SMasahiro Yamada	help
401506f1d07SSam Ravnborg	  This enables support for systems with more than one CPU. If you have
4024a474157SRobert Graffham	  a system with only one CPU, say N. If you have a system with more
4034a474157SRobert Graffham	  than one CPU, say Y.
404506f1d07SSam Ravnborg
4054a474157SRobert Graffham	  If you say N here, the kernel will run on uni- and multiprocessor
406506f1d07SSam Ravnborg	  machines, but will use only one CPU of a multiprocessor machine. If
407506f1d07SSam Ravnborg	  you say Y here, the kernel will run on many, but not all,
4084a474157SRobert Graffham	  uniprocessor machines. On a uniprocessor machine, the kernel
409506f1d07SSam Ravnborg	  will run faster if you say N here.
410506f1d07SSam Ravnborg
411506f1d07SSam Ravnborg	  Note that if you say Y here and choose architecture "586" or
412506f1d07SSam Ravnborg	  "Pentium" under "Processor family", the kernel will not work on 486
413506f1d07SSam Ravnborg	  architectures. Similarly, multiprocessor kernels for the "PPro"
414506f1d07SSam Ravnborg	  architecture may not work on all Pentium based boards.
415506f1d07SSam Ravnborg
416506f1d07SSam Ravnborg	  People using multiprocessor machines who say Y here should also say
417506f1d07SSam Ravnborg	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
418506f1d07SSam Ravnborg	  Management" code will be disabled if you say Y here.
419506f1d07SSam Ravnborg
420cb1aaebeSMauro Carvalho Chehab	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
4214f4cfa6cSMauro Carvalho Chehab	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
422506f1d07SSam Ravnborg	  <http://www.tldp.org/docs.html#howto>.
423506f1d07SSam Ravnborg
424506f1d07SSam Ravnborg	  If you don't know what to do here, say N.
425506f1d07SSam Ravnborg
4269def39beSJosh Triplettconfig X86_FEATURE_NAMES
4279def39beSJosh Triplett	bool "Processor feature human-readable names" if EMBEDDED
4289def39beSJosh Triplett	default y
429a7f7f624SMasahiro Yamada	help
4309def39beSJosh Triplett	  This option compiles in a table of x86 feature bits and corresponding
4319def39beSJosh Triplett	  names.  This is required to support /proc/cpuinfo and a few kernel
4329def39beSJosh Triplett	  messages.  You can disable this to save space, at the expense of
4339def39beSJosh Triplett	  making those few kernel messages show numeric feature bits instead.
4349def39beSJosh Triplett
4359def39beSJosh Triplett	  If in doubt, say Y.
4369def39beSJosh Triplett
43706cd9a7dSYinghai Luconfig X86_X2APIC
43806cd9a7dSYinghai Lu	bool "Support x2apic"
43919e3d60dSJan Kiszka	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
440a7f7f624SMasahiro Yamada	help
44106cd9a7dSYinghai Lu	  This enables x2apic support on CPUs that have this feature.
44206cd9a7dSYinghai Lu
44306cd9a7dSYinghai Lu	  This allows 32-bit apic IDs (so it can support very large systems),
44406cd9a7dSYinghai Lu	  and accesses the local apic via MSRs not via mmio.
44506cd9a7dSYinghai Lu
44606cd9a7dSYinghai Lu	  If you don't know what to do here, say N.
44706cd9a7dSYinghai Lu
4486695c85bSYinghai Luconfig X86_MPPARSE
4494590d98fSAndy Shevchenko	bool "Enable MPS table" if ACPI
4507a527688SJan Beulich	default y
4515ab74722SIngo Molnar	depends on X86_LOCAL_APIC
452a7f7f624SMasahiro Yamada	help
4536695c85bSYinghai Lu	  For old smp systems that do not have proper acpi support. Newer systems
4546695c85bSYinghai Lu	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
4556695c85bSYinghai Lu
456ddd70cf9SJun Nakajimaconfig GOLDFISH
457ddd70cf9SJun Nakajima	def_bool y
458ddd70cf9SJun Nakajima	depends on X86_GOLDFISH
459ddd70cf9SJun Nakajima
46076b04384SDavid Woodhouseconfig RETPOLINE
46176b04384SDavid Woodhouse	bool "Avoid speculative indirect branches in kernel"
46276b04384SDavid Woodhouse	default y
46376b04384SDavid Woodhouse	help
46476b04384SDavid Woodhouse	  Compile kernel with the retpoline compiler options to guard against
46576b04384SDavid Woodhouse	  kernel-to-user data leaks by avoiding speculative indirect
46676b04384SDavid Woodhouse	  branches. Requires a compiler with -mindirect-branch=thunk-extern
46776b04384SDavid Woodhouse	  support for full protection. The kernel may run slower.
46876b04384SDavid Woodhouse
469e463a09aSPeter Zijlstraconfig CC_HAS_SLS
470e463a09aSPeter Zijlstra	def_bool $(cc-option,-mharden-sls=all)
471e463a09aSPeter Zijlstra
472e463a09aSPeter Zijlstraconfig SLS
473e463a09aSPeter Zijlstra	bool "Mitigate Straight-Line-Speculation"
474e463a09aSPeter Zijlstra	depends on CC_HAS_SLS && X86_64
475e463a09aSPeter Zijlstra	default n
476e463a09aSPeter Zijlstra	help
477e463a09aSPeter Zijlstra	  Compile the kernel with straight-line-speculation options to guard
478e463a09aSPeter Zijlstra	  against straight line speculation. The kernel image might be slightly
479e463a09aSPeter Zijlstra	  larger.
480e463a09aSPeter Zijlstra
481e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL
482e6d42931SJohannes Weiner	bool "x86 CPU resource control support"
4836fe07ce3SBabu Moger	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
48459fe5a77SThomas Gleixner	select KERNFS
485e79f15a4SChen Yu	select PROC_CPU_RESCTRL		if PROC_FS
48678e99b4aSFenghua Yu	help
487e6d42931SJohannes Weiner	  Enable x86 CPU resource control support.
4886fe07ce3SBabu Moger
4896fe07ce3SBabu Moger	  Provide support for the allocation and monitoring of system resources
4906fe07ce3SBabu Moger	  usage by the CPU.
4916fe07ce3SBabu Moger
4926fe07ce3SBabu Moger	  Intel calls this Intel Resource Director Technology
4936fe07ce3SBabu Moger	  (Intel(R) RDT). More information about RDT can be found in the
4946fe07ce3SBabu Moger	  Intel x86 Architecture Software Developer Manual.
4956fe07ce3SBabu Moger
4966fe07ce3SBabu Moger	  AMD calls this AMD Platform Quality of Service (AMD QoS).
4976fe07ce3SBabu Moger	  More information about AMD QoS can be found in the AMD64 Technology
4986fe07ce3SBabu Moger	  Platform Quality of Service Extensions manual.
49978e99b4aSFenghua Yu
50078e99b4aSFenghua Yu	  Say N if unsure.
50178e99b4aSFenghua Yu
5028425091fSRavikiran G Thirumalaiif X86_32
503a0d0bb4dSRandy Dunlapconfig X86_BIGSMP
504a0d0bb4dSRandy Dunlap	bool "Support for big SMP systems with more than 8 CPUs"
505a0d0bb4dSRandy Dunlap	depends on SMP
506a7f7f624SMasahiro Yamada	help
507e133f6eaSRandy Dunlap	  This option is needed for the systems that have more than 8 CPUs.
508a0d0bb4dSRandy Dunlap
509c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM
510c5c606d9SRavikiran G Thirumalai	bool "Support for extended (non-PC) x86 platforms"
511c5c606d9SRavikiran G Thirumalai	default y
512a7f7f624SMasahiro Yamada	help
51306ac8346SIngo Molnar	  If you disable this option then the kernel will only support
51406ac8346SIngo Molnar	  standard PC platforms. (which covers the vast majority of
51506ac8346SIngo Molnar	  systems out there.)
51606ac8346SIngo Molnar
5178425091fSRavikiran G Thirumalai	  If you enable this option then you'll be able to select support
5188425091fSRavikiran G Thirumalai	  for the following (non-PC) 32 bit x86 platforms:
519cb7b8023SBen Hutchings		Goldfish (Android emulator)
5208425091fSRavikiran G Thirumalai		AMD Elan
5218425091fSRavikiran G Thirumalai		RDC R-321x SoC
5228425091fSRavikiran G Thirumalai		SGI 320/540 (Visual Workstation)
52383125a3aSAlessandro Rubini		STA2X11-based (e.g. Northville)
5243f4110a4SThomas Gleixner		Moorestown MID devices
52506ac8346SIngo Molnar
52606ac8346SIngo Molnar	  If you have one of these systems, or if you want to build a
52706ac8346SIngo Molnar	  generic distribution kernel, say Y here - otherwise say N.
5288425091fSRavikiran G Thirumalaiendif
52906ac8346SIngo Molnar
5308425091fSRavikiran G Thirumalaiif X86_64
5318425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM
5328425091fSRavikiran G Thirumalai	bool "Support for extended (non-PC) x86 platforms"
5338425091fSRavikiran G Thirumalai	default y
534a7f7f624SMasahiro Yamada	help
5358425091fSRavikiran G Thirumalai	  If you disable this option then the kernel will only support
5368425091fSRavikiran G Thirumalai	  standard PC platforms. (which covers the vast majority of
5378425091fSRavikiran G Thirumalai	  systems out there.)
5388425091fSRavikiran G Thirumalai
5398425091fSRavikiran G Thirumalai	  If you enable this option then you'll be able to select support
5408425091fSRavikiran G Thirumalai	  for the following (non-PC) 64 bit x86 platforms:
54144b111b5SSteffen Persvold		Numascale NumaChip
5428425091fSRavikiran G Thirumalai		ScaleMP vSMP
5438425091fSRavikiran G Thirumalai		SGI Ultraviolet
5448425091fSRavikiran G Thirumalai
5458425091fSRavikiran G Thirumalai	  If you have one of these systems, or if you want to build a
5468425091fSRavikiran G Thirumalai	  generic distribution kernel, say Y here - otherwise say N.
5478425091fSRavikiran G Thirumalaiendif
548c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms
549c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions
55044b111b5SSteffen Persvoldconfig X86_NUMACHIP
55144b111b5SSteffen Persvold	bool "Numascale NumaChip"
55244b111b5SSteffen Persvold	depends on X86_64
55344b111b5SSteffen Persvold	depends on X86_EXTENDED_PLATFORM
55444b111b5SSteffen Persvold	depends on NUMA
55544b111b5SSteffen Persvold	depends on SMP
55644b111b5SSteffen Persvold	depends on X86_X2APIC
557f9726bfdSDaniel J Blueman	depends on PCI_MMCONFIG
558a7f7f624SMasahiro Yamada	help
55944b111b5SSteffen Persvold	  Adds support for Numascale NumaChip large-SMP systems. Needed to
56044b111b5SSteffen Persvold	  enable more than ~168 cores.
56144b111b5SSteffen Persvold	  If you don't have one of these, you should say N here.
56203b48632SNick Piggin
5636a48565eSIngo Molnarconfig X86_VSMP
564c5c606d9SRavikiran G Thirumalai	bool "ScaleMP vSMP"
5656276a074SBorislav Petkov	select HYPERVISOR_GUEST
5666a48565eSIngo Molnar	select PARAVIRT
5676a48565eSIngo Molnar	depends on X86_64 && PCI
568c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
569ead91d4bSShai Fultheim	depends on SMP
570a7f7f624SMasahiro Yamada	help
5716a48565eSIngo Molnar	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
5726a48565eSIngo Molnar	  supposed to run on these EM64T-based machines.  Only choose this option
5736a48565eSIngo Molnar	  if you have one of these machines.
5746a48565eSIngo Molnar
575c5c606d9SRavikiran G Thirumalaiconfig X86_UV
576c5c606d9SRavikiran G Thirumalai	bool "SGI Ultraviolet"
577c5c606d9SRavikiran G Thirumalai	depends on X86_64
578c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
57954c28d29SJack Steiner	depends on NUMA
5801ecb4ae5SAndrew Morton	depends on EFI
581c2209ea5SIngo Molnar	depends on KEXEC_CORE
5829d6c26e7SSuresh Siddha	depends on X86_X2APIC
5831222e564SIngo Molnar	depends on PCI
584a7f7f624SMasahiro Yamada	help
585c5c606d9SRavikiran G Thirumalai	  This option is needed in order to support SGI Ultraviolet systems.
586c5c606d9SRavikiran G Thirumalai	  If you don't have one of these, you should say N here.
587c5c606d9SRavikiran G Thirumalai
588c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms
589c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions
590506f1d07SSam Ravnborg
591ddd70cf9SJun Nakajimaconfig X86_GOLDFISH
592ddd70cf9SJun Nakajima	bool "Goldfish (Virtual Platform)"
593cb7b8023SBen Hutchings	depends on X86_EXTENDED_PLATFORM
594a7f7f624SMasahiro Yamada	help
595ddd70cf9SJun Nakajima	 Enable support for the Goldfish virtual platform used primarily
596ddd70cf9SJun Nakajima	 for Android development. Unless you are building for the Android
597ddd70cf9SJun Nakajima	 Goldfish emulator say N here.
598ddd70cf9SJun Nakajima
599c751e17bSThomas Gleixnerconfig X86_INTEL_CE
600c751e17bSThomas Gleixner	bool "CE4100 TV platform"
601c751e17bSThomas Gleixner	depends on PCI
602c751e17bSThomas Gleixner	depends on PCI_GODIRECT
6036084a6e2SJiang Liu	depends on X86_IO_APIC
604c751e17bSThomas Gleixner	depends on X86_32
605c751e17bSThomas Gleixner	depends on X86_EXTENDED_PLATFORM
60637bc9f50SDirk Brandewie	select X86_REBOOTFIXUPS
607da6b737bSSebastian Andrzej Siewior	select OF
608da6b737bSSebastian Andrzej Siewior	select OF_EARLY_FLATTREE
609a7f7f624SMasahiro Yamada	help
610c751e17bSThomas Gleixner	  Select for the Intel CE media processor (CE4100) SOC.
611c751e17bSThomas Gleixner	  This option compiles in support for the CE4100 SOC for settop
612c751e17bSThomas Gleixner	  boxes and media devices.
613c751e17bSThomas Gleixner
6144cb9b00fSDavid Cohenconfig X86_INTEL_MID
61543605ef1SAlan Cox	bool "Intel MID platform support"
61643605ef1SAlan Cox	depends on X86_EXTENDED_PLATFORM
617edc6bc78SDavid Cohen	depends on X86_PLATFORM_DEVICES
6181ea7c673SAlan Cox	depends on PCI
6193fda5bb4SAndy Shevchenko	depends on X86_64 || (PCI_GOANY && X86_32)
6201ea7c673SAlan Cox	depends on X86_IO_APIC
6214cb9b00fSDavid Cohen	select I2C
6227c9c3a1eSAlan Cox	select DW_APB_TIMER
62354b34aa0SMika Westerberg	select INTEL_SCU_PCI
624a7f7f624SMasahiro Yamada	help
6254cb9b00fSDavid Cohen	  Select to build a kernel capable of supporting Intel MID (Mobile
6264cb9b00fSDavid Cohen	  Internet Device) platform systems which do not have the PCI legacy
6274cb9b00fSDavid Cohen	  interfaces. If you are building for a PC class system say N here.
6281ea7c673SAlan Cox
6294cb9b00fSDavid Cohen	  Intel MID platforms are based on an Intel processor and chipset which
6304cb9b00fSDavid Cohen	  consume less power than most of the x86 derivatives.
63143605ef1SAlan Cox
6328bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK
6338bbc2a13SBryan O'Donoghue	bool "Intel Quark platform support"
6348bbc2a13SBryan O'Donoghue	depends on X86_32
6358bbc2a13SBryan O'Donoghue	depends on X86_EXTENDED_PLATFORM
6368bbc2a13SBryan O'Donoghue	depends on X86_PLATFORM_DEVICES
6378bbc2a13SBryan O'Donoghue	depends on X86_TSC
6388bbc2a13SBryan O'Donoghue	depends on PCI
6398bbc2a13SBryan O'Donoghue	depends on PCI_GOANY
6408bbc2a13SBryan O'Donoghue	depends on X86_IO_APIC
6418bbc2a13SBryan O'Donoghue	select IOSF_MBI
6428bbc2a13SBryan O'Donoghue	select INTEL_IMR
6439ab6eb51SAndy Shevchenko	select COMMON_CLK
644a7f7f624SMasahiro Yamada	help
6458bbc2a13SBryan O'Donoghue	  Select to include support for Quark X1000 SoC.
6468bbc2a13SBryan O'Donoghue	  Say Y here if you have a Quark based system such as the Arduino
6478bbc2a13SBryan O'Donoghue	  compatible Intel Galileo.
6488bbc2a13SBryan O'Donoghue
6493d48aab1SMika Westerbergconfig X86_INTEL_LPSS
6503d48aab1SMika Westerberg	bool "Intel Low Power Subsystem Support"
6515962dd22SSinan Kaya	depends on X86 && ACPI && PCI
6523d48aab1SMika Westerberg	select COMMON_CLK
6530f531431SMathias Nyman	select PINCTRL
654eebb3e8dSAndy Shevchenko	select IOSF_MBI
655a7f7f624SMasahiro Yamada	help
6563d48aab1SMika Westerberg	  Select to build support for Intel Low Power Subsystem such as
6573d48aab1SMika Westerberg	  found on Intel Lynxpoint PCH. Selecting this option enables
6580f531431SMathias Nyman	  things like clock tree (common clock framework) and pincontrol
6590f531431SMathias Nyman	  which are needed by the LPSS peripheral drivers.
6603d48aab1SMika Westerberg
66192082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE
66292082a88SKen Xue	bool "AMD ACPI2Platform devices support"
66392082a88SKen Xue	depends on ACPI
66492082a88SKen Xue	select COMMON_CLK
66592082a88SKen Xue	select PINCTRL
666a7f7f624SMasahiro Yamada	help
66792082a88SKen Xue	  Select to interpret AMD specific ACPI device to platform device
66892082a88SKen Xue	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
66992082a88SKen Xue	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
67092082a88SKen Xue	  implemented under PINCTRL subsystem.
67192082a88SKen Xue
672ced3ce76SDavid E. Boxconfig IOSF_MBI
673ced3ce76SDavid E. Box	tristate "Intel SoC IOSF Sideband support for SoC platforms"
674ced3ce76SDavid E. Box	depends on PCI
675a7f7f624SMasahiro Yamada	help
676ced3ce76SDavid E. Box	  This option enables sideband register access support for Intel SoC
677ced3ce76SDavid E. Box	  platforms. On these platforms the IOSF sideband is used in lieu of
678ced3ce76SDavid E. Box	  MSR's for some register accesses, mostly but not limited to thermal
679ced3ce76SDavid E. Box	  and power. Drivers may query the availability of this device to
680ced3ce76SDavid E. Box	  determine if they need the sideband in order to work on these
681ced3ce76SDavid E. Box	  platforms. The sideband is available on the following SoC products.
682ced3ce76SDavid E. Box	  This list is not meant to be exclusive.
683ced3ce76SDavid E. Box	   - BayTrail
684ced3ce76SDavid E. Box	   - Braswell
685ced3ce76SDavid E. Box	   - Quark
686ced3ce76SDavid E. Box
687ced3ce76SDavid E. Box	  You should say Y if you are running a kernel on one of these SoC's.
688ced3ce76SDavid E. Box
689ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG
690ed2226bdSDavid E. Box	bool "Enable IOSF sideband access through debugfs"
691ed2226bdSDavid E. Box	depends on IOSF_MBI && DEBUG_FS
692a7f7f624SMasahiro Yamada	help
693ed2226bdSDavid E. Box	  Select this option to expose the IOSF sideband access registers (MCR,
694ed2226bdSDavid E. Box	  MDR, MCRX) through debugfs to write and read register information from
695ed2226bdSDavid E. Box	  different units on the SoC. This is most useful for obtaining device
696ed2226bdSDavid E. Box	  state information for debug and analysis. As this is a general access
697ed2226bdSDavid E. Box	  mechanism, users of this option would have specific knowledge of the
698ed2226bdSDavid E. Box	  device they want to access.
699ed2226bdSDavid E. Box
700ed2226bdSDavid E. Box	  If you don't require the option or are in doubt, say N.
701ed2226bdSDavid E. Box
702c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X
703c5c606d9SRavikiran G Thirumalai	bool "RDC R-321x SoC"
704506f1d07SSam Ravnborg	depends on X86_32
705c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
706c5c606d9SRavikiran G Thirumalai	select M486
707c5c606d9SRavikiran G Thirumalai	select X86_REBOOTFIXUPS
708a7f7f624SMasahiro Yamada	help
709c5c606d9SRavikiran G Thirumalai	  This option is needed for RDC R-321x system-on-chip, also known
710c5c606d9SRavikiran G Thirumalai	  as R-8610-(G).
711c5c606d9SRavikiran G Thirumalai	  If you don't have one of these chips, you should say N here.
712c5c606d9SRavikiran G Thirumalai
713e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD
7149c398017SIngo Molnar	bool "Support non-standard 32-bit SMP architectures"
7159c398017SIngo Molnar	depends on X86_32 && SMP
716c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
717a7f7f624SMasahiro Yamada	help
718b5660ba7SH. Peter Anvin	  This option compiles in the bigsmp and STA2X11 default
719b5660ba7SH. Peter Anvin	  subarchitectures.  It is intended for a generic binary
720b5660ba7SH. Peter Anvin	  kernel. If you select them all, kernel will probe it one by
721b5660ba7SH. Peter Anvin	  one and will fallback to default.
722d49c4288SYinghai Lu
723c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms
724d49c4288SYinghai Lu
725d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE
7266fc108a0SJan Beulich	def_bool y
727d949f36fSLinus Torvalds	# MCE code calls memory_failure():
728d949f36fSLinus Torvalds	depends on X86_MCE
729d949f36fSLinus Torvalds	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
730d949f36fSLinus Torvalds	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
731d949f36fSLinus Torvalds	depends on X86_64 || !SPARSEMEM
732d949f36fSLinus Torvalds	select ARCH_SUPPORTS_MEMORY_FAILURE
733d949f36fSLinus Torvalds
73483125a3aSAlessandro Rubiniconfig STA2X11
73583125a3aSAlessandro Rubini	bool "STA2X11 Companion Chip Support"
73683125a3aSAlessandro Rubini	depends on X86_32_NON_STANDARD && PCI
73783125a3aSAlessandro Rubini	select SWIOTLB
73883125a3aSAlessandro Rubini	select MFD_STA2X11
7390145071bSLinus Walleij	select GPIOLIB
740a7f7f624SMasahiro Yamada	help
74183125a3aSAlessandro Rubini	  This adds support for boards based on the STA2X11 IO-Hub,
74283125a3aSAlessandro Rubini	  a.k.a. "ConneXt". The chip is used in place of the standard
74383125a3aSAlessandro Rubini	  PC chipset, so all "standard" peripherals are missing. If this
74483125a3aSAlessandro Rubini	  option is selected the kernel will still be able to boot on
74583125a3aSAlessandro Rubini	  standard PC machines.
74683125a3aSAlessandro Rubini
74782148d1dSShérabconfig X86_32_IRIS
74882148d1dSShérab	tristate "Eurobraille/Iris poweroff module"
74982148d1dSShérab	depends on X86_32
750a7f7f624SMasahiro Yamada	help
75182148d1dSShérab	  The Iris machines from EuroBraille do not have APM or ACPI support
75282148d1dSShérab	  to shut themselves down properly.  A special I/O sequence is
75382148d1dSShérab	  needed to do so, which is what this module does at
75482148d1dSShérab	  kernel shutdown.
75582148d1dSShérab
75682148d1dSShérab	  This is only for Iris machines from EuroBraille.
75782148d1dSShérab
75882148d1dSShérab	  If unused, say N.
75982148d1dSShérab
760ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER
7613c2362e6SHarvey Harrison	def_bool y
7623c2362e6SHarvey Harrison	prompt "Single-depth WCHAN output"
763a87d0914SKen Chen	depends on X86
764a7f7f624SMasahiro Yamada	help
765506f1d07SSam Ravnborg	  Calculate simpler /proc/<PID>/wchan values. If this option
766506f1d07SSam Ravnborg	  is disabled then wchan values will recurse back to the
767506f1d07SSam Ravnborg	  caller function. This provides more accurate wchan values,
768506f1d07SSam Ravnborg	  at the expense of slightly more scheduling overhead.
769506f1d07SSam Ravnborg
770506f1d07SSam Ravnborg	  If in doubt, say "Y".
771506f1d07SSam Ravnborg
7726276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST
7736276a074SBorislav Petkov	bool "Linux guest support"
774a7f7f624SMasahiro Yamada	help
7756276a074SBorislav Petkov	  Say Y here to enable options for running Linux under various hyper-
7766276a074SBorislav Petkov	  visors. This option enables basic hypervisor detection and platform
7776276a074SBorislav Petkov	  setup.
778506f1d07SSam Ravnborg
7796276a074SBorislav Petkov	  If you say N, all options in this submenu will be skipped and
7806276a074SBorislav Petkov	  disabled, and Linux guest support won't be built in.
781506f1d07SSam Ravnborg
7826276a074SBorislav Petkovif HYPERVISOR_GUEST
783506f1d07SSam Ravnborg
784e61bd94aSEduardo Pereira Habkostconfig PARAVIRT
785e61bd94aSEduardo Pereira Habkost	bool "Enable paravirtualization code"
786a0e2bf7cSJuergen Gross	depends on HAVE_STATIC_CALL
787a7f7f624SMasahiro Yamada	help
788e61bd94aSEduardo Pereira Habkost	  This changes the kernel so it can modify itself when it is run
789e61bd94aSEduardo Pereira Habkost	  under a hypervisor, potentially improving performance significantly
790e61bd94aSEduardo Pereira Habkost	  over full virtualization.  However, when run without a hypervisor
791e61bd94aSEduardo Pereira Habkost	  the kernel is theoretically slower and slightly larger.
792e61bd94aSEduardo Pereira Habkost
793c00a280aSJuergen Grossconfig PARAVIRT_XXL
794c00a280aSJuergen Gross	bool
795c00a280aSJuergen Gross
7966276a074SBorislav Petkovconfig PARAVIRT_DEBUG
7976276a074SBorislav Petkov	bool "paravirt-ops debugging"
7986276a074SBorislav Petkov	depends on PARAVIRT && DEBUG_KERNEL
799a7f7f624SMasahiro Yamada	help
8006276a074SBorislav Petkov	  Enable to debug paravirt_ops internals.  Specifically, BUG if
8016276a074SBorislav Petkov	  a paravirt_op is missing when it is called.
8026276a074SBorislav Petkov
803b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS
804b4ecc126SJeremy Fitzhardinge	bool "Paravirtualization layer for spinlocks"
8056ea30386SKees Cook	depends on PARAVIRT && SMP
806a7f7f624SMasahiro Yamada	help
807b4ecc126SJeremy Fitzhardinge	  Paravirtualized spinlocks allow a pvops backend to replace the
808b4ecc126SJeremy Fitzhardinge	  spinlock implementation with something virtualization-friendly
809b4ecc126SJeremy Fitzhardinge	  (for example, block the virtual CPU rather than spinning).
810b4ecc126SJeremy Fitzhardinge
8114c4e4f61SRaghavendra K T	  It has a minimal impact on native kernels and gives a nice performance
8124c4e4f61SRaghavendra K T	  benefit on paravirtualized KVM / Xen kernels.
813b4ecc126SJeremy Fitzhardinge
8144c4e4f61SRaghavendra K T	  If you are unsure how to answer this question, answer Y.
815b4ecc126SJeremy Fitzhardinge
816ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR
817ecca2502SZhao Yakui	def_bool n
818ecca2502SZhao Yakui
8196276a074SBorislav Petkovsource "arch/x86/xen/Kconfig"
8206276a074SBorislav Petkov
8216276a074SBorislav Petkovconfig KVM_GUEST
8226276a074SBorislav Petkov	bool "KVM Guest support (including kvmclock)"
8236276a074SBorislav Petkov	depends on PARAVIRT
8246276a074SBorislav Petkov	select PARAVIRT_CLOCK
825a1c4423bSMarcelo Tosatti	select ARCH_CPUIDLE_HALTPOLL
826b1d40575SVitaly Kuznetsov	select X86_HV_CALLBACK_VECTOR
8276276a074SBorislav Petkov	default y
828a7f7f624SMasahiro Yamada	help
8296276a074SBorislav Petkov	  This option enables various optimizations for running under the KVM
8306276a074SBorislav Petkov	  hypervisor. It includes a paravirtualized clock, so that instead
8316276a074SBorislav Petkov	  of relying on a PIT (or probably other) emulation by the
8326276a074SBorislav Petkov	  underlying device model, the host provides the guest with
8336276a074SBorislav Petkov	  timing infrastructure such as time of day, and system time
8346276a074SBorislav Petkov
835a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL
836a1c4423bSMarcelo Tosatti	def_bool n
837a1c4423bSMarcelo Tosatti	prompt "Disable host haltpoll when loading haltpoll driver"
838a1c4423bSMarcelo Tosatti	help
839a1c4423bSMarcelo Tosatti	  If virtualized under KVM, disable host haltpoll.
840a1c4423bSMarcelo Tosatti
8417733607fSMaran Wilsonconfig PVH
8427733607fSMaran Wilson	bool "Support for running PVH guests"
843a7f7f624SMasahiro Yamada	help
8447733607fSMaran Wilson	  This option enables the PVH entry point for guest virtual machines
8457733607fSMaran Wilson	  as specified in the x86/HVM direct boot ABI.
8467733607fSMaran Wilson
8476276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING
8486276a074SBorislav Petkov	bool "Paravirtual steal time accounting"
8496276a074SBorislav Petkov	depends on PARAVIRT
850a7f7f624SMasahiro Yamada	help
8516276a074SBorislav Petkov	  Select this option to enable fine granularity task steal time
8526276a074SBorislav Petkov	  accounting. Time spent executing other tasks in parallel with
8536276a074SBorislav Petkov	  the current vCPU is discounted from the vCPU power. To account for
8546276a074SBorislav Petkov	  that, there can be a small performance impact.
8556276a074SBorislav Petkov
8566276a074SBorislav Petkov	  If in doubt, say N here.
8576276a074SBorislav Petkov
8587af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK
8597af192c9SGerd Hoffmann	bool
8607af192c9SGerd Hoffmann
8614a362601SJan Kiszkaconfig JAILHOUSE_GUEST
8624a362601SJan Kiszka	bool "Jailhouse non-root cell support"
863abde587bSArnd Bergmann	depends on X86_64 && PCI
86487e65d05SJan Kiszka	select X86_PM_TIMER
865a7f7f624SMasahiro Yamada	help
8664a362601SJan Kiszka	  This option allows to run Linux as guest in a Jailhouse non-root
8674a362601SJan Kiszka	  cell. You can leave this option disabled if you only want to start
8684a362601SJan Kiszka	  Jailhouse and run Linux afterwards in the root cell.
8694a362601SJan Kiszka
870ec7972c9SZhao Yakuiconfig ACRN_GUEST
871ec7972c9SZhao Yakui	bool "ACRN Guest support"
872ec7972c9SZhao Yakui	depends on X86_64
873498ad393SZhao Yakui	select X86_HV_CALLBACK_VECTOR
874ec7972c9SZhao Yakui	help
875ec7972c9SZhao Yakui	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
876ec7972c9SZhao Yakui	  a flexible, lightweight reference open-source hypervisor, built with
877ec7972c9SZhao Yakui	  real-time and safety-criticality in mind. It is built for embedded
878ec7972c9SZhao Yakui	  IOT with small footprint and real-time features. More details can be
879ec7972c9SZhao Yakui	  found in https://projectacrn.org/.
880ec7972c9SZhao Yakui
8816276a074SBorislav Petkovendif #HYPERVISOR_GUEST
88297349135SJeremy Fitzhardinge
883506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu"
884506f1d07SSam Ravnborg
885506f1d07SSam Ravnborgconfig HPET_TIMER
8863c2362e6SHarvey Harrison	def_bool X86_64
887506f1d07SSam Ravnborg	prompt "HPET Timer Support" if X86_32
888a7f7f624SMasahiro Yamada	help
889506f1d07SSam Ravnborg	  Use the IA-PC HPET (High Precision Event Timer) to manage
890506f1d07SSam Ravnborg	  time in preference to the PIT and RTC, if a HPET is
891506f1d07SSam Ravnborg	  present.
892506f1d07SSam Ravnborg	  HPET is the next generation timer replacing legacy 8254s.
893506f1d07SSam Ravnborg	  The HPET provides a stable time base on SMP
894506f1d07SSam Ravnborg	  systems, unlike the TSC, but it is more expensive to access,
8954e7f9df2SMichael S. Tsirkin	  as it is off-chip.  The interface used is documented
8964e7f9df2SMichael S. Tsirkin	  in the HPET spec, revision 1.
897506f1d07SSam Ravnborg
898506f1d07SSam Ravnborg	  You can safely choose Y here.  However, HPET will only be
899506f1d07SSam Ravnborg	  activated if the platform and the BIOS support this feature.
900506f1d07SSam Ravnborg	  Otherwise the 8254 will be used for timing services.
901506f1d07SSam Ravnborg
902506f1d07SSam Ravnborg	  Choose N to continue using the legacy 8254 timer.
903506f1d07SSam Ravnborg
904506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC
9053c2362e6SHarvey Harrison	def_bool y
9063228e1dcSAnand K Mistry	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
907506f1d07SSam Ravnborg
9086a108a14SDavid Rientjes# Mark as expert because too many people got it wrong.
909506f1d07SSam Ravnborg# The code disables itself when not needed.
9107ae9392cSThomas Petazzoniconfig DMI
9117ae9392cSThomas Petazzoni	default y
912cf074402SArd Biesheuvel	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
9136a108a14SDavid Rientjes	bool "Enable DMI scanning" if EXPERT
914a7f7f624SMasahiro Yamada	help
9157ae9392cSThomas Petazzoni	  Enabled scanning of DMI to identify machine quirks. Say Y
9167ae9392cSThomas Petazzoni	  here unless you have verified that your setup is not
9177ae9392cSThomas Petazzoni	  affected by entries in the DMI blacklist. Required by PNP
9187ae9392cSThomas Petazzoni	  BIOS code.
9197ae9392cSThomas Petazzoni
920506f1d07SSam Ravnborgconfig GART_IOMMU
92138901f1cSAndi Kleen	bool "Old AMD GART IOMMU support"
9222f9237d4SChristoph Hellwig	select DMA_OPS
923a4ce5a48SChristoph Hellwig	select IOMMU_HELPER
924506f1d07SSam Ravnborg	select SWIOTLB
92523ac4ae8SAndreas Herrmann	depends on X86_64 && PCI && AMD_NB
926a7f7f624SMasahiro Yamada	help
927ced3c42cSIngo Molnar	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
928ced3c42cSIngo Molnar	  GART based hardware IOMMUs.
929ced3c42cSIngo Molnar
930ced3c42cSIngo Molnar	  The GART supports full DMA access for devices with 32-bit access
931ced3c42cSIngo Molnar	  limitations, on systems with more than 3 GB. This is usually needed
932ced3c42cSIngo Molnar	  for USB, sound, many IDE/SATA chipsets and some other devices.
933ced3c42cSIngo Molnar
934ced3c42cSIngo Molnar	  Newer systems typically have a modern AMD IOMMU, supported via
935ced3c42cSIngo Molnar	  the CONFIG_AMD_IOMMU=y config option.
936ced3c42cSIngo Molnar
937ced3c42cSIngo Molnar	  In normal configurations this driver is only active when needed:
938ced3c42cSIngo Molnar	  there's more than 3 GB of memory and the system contains a
939ced3c42cSIngo Molnar	  32-bit limited device.
940ced3c42cSIngo Molnar
941ced3c42cSIngo Molnar	  If unsure, say Y.
942506f1d07SSam Ravnborg
9431184dc2fSMike Travisconfig MAXSMP
944ddb0c5a6SSamuel Thibault	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
9456ea30386SKees Cook	depends on X86_64 && SMP && DEBUG_KERNEL
94636f5101aSMike Travis	select CPUMASK_OFFSTACK
947a7f7f624SMasahiro Yamada	help
948ddb0c5a6SSamuel Thibault	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
9491184dc2fSMike Travis	  If unsure, say N.
950506f1d07SSam Ravnborg
951aec6487eSIngo Molnar#
952aec6487eSIngo Molnar# The maximum number of CPUs supported:
953aec6487eSIngo Molnar#
954aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
955aec6487eSIngo Molnar# and which can be configured interactively in the
956aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
957aec6487eSIngo Molnar#
958aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on
959aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel.
960aec6487eSIngo Molnar#
961aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable
962aec6487eSIngo Molnar#   interactive configuration. )
963aec6487eSIngo Molnar#
964a0d0bb4dSRandy Dunlap
965aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN
966a0d0bb4dSRandy Dunlap	int
967aec6487eSIngo Molnar	default NR_CPUS_RANGE_END if MAXSMP
968a0d0bb4dSRandy Dunlap	default    1 if !SMP
969a0d0bb4dSRandy Dunlap	default    2
970a0d0bb4dSRandy Dunlap
971aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END
972a0d0bb4dSRandy Dunlap	int
973a0d0bb4dSRandy Dunlap	depends on X86_32
974aec6487eSIngo Molnar	default   64 if  SMP &&  X86_BIGSMP
975aec6487eSIngo Molnar	default    8 if  SMP && !X86_BIGSMP
976a0d0bb4dSRandy Dunlap	default    1 if !SMP
977a0d0bb4dSRandy Dunlap
978aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END
979a0d0bb4dSRandy Dunlap	int
980a0d0bb4dSRandy Dunlap	depends on X86_64
9811edae1aeSScott Wood	default 8192 if  SMP && CPUMASK_OFFSTACK
9821edae1aeSScott Wood	default  512 if  SMP && !CPUMASK_OFFSTACK
983a0d0bb4dSRandy Dunlap	default    1 if !SMP
984aec6487eSIngo Molnar
985aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT
986aec6487eSIngo Molnar	int
987aec6487eSIngo Molnar	depends on X86_32
988aec6487eSIngo Molnar	default   32 if  X86_BIGSMP
989aec6487eSIngo Molnar	default    8 if  SMP
990aec6487eSIngo Molnar	default    1 if !SMP
991aec6487eSIngo Molnar
992aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT
993aec6487eSIngo Molnar	int
994aec6487eSIngo Molnar	depends on X86_64
995a0d0bb4dSRandy Dunlap	default 8192 if  MAXSMP
996a0d0bb4dSRandy Dunlap	default   64 if  SMP
997aec6487eSIngo Molnar	default    1 if !SMP
998a0d0bb4dSRandy Dunlap
999506f1d07SSam Ravnborgconfig NR_CPUS
100036f5101aSMike Travis	int "Maximum number of CPUs" if SMP && !MAXSMP
1001aec6487eSIngo Molnar	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1002aec6487eSIngo Molnar	default NR_CPUS_DEFAULT
1003a7f7f624SMasahiro Yamada	help
1004506f1d07SSam Ravnborg	  This allows you to specify the maximum number of CPUs which this
1005bb61ccc7SJosh Boyer	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1006cad14bb9SKirill A. Shutemov	  supported value is 8192, otherwise the maximum value is 512.  The
1007506f1d07SSam Ravnborg	  minimum value which makes sense is 2.
1008506f1d07SSam Ravnborg
1009aec6487eSIngo Molnar	  This is purely to save memory: each supported CPU adds about 8KB
1010aec6487eSIngo Molnar	  to the kernel image.
1011506f1d07SSam Ravnborg
101266558b73STim Chenconfig SCHED_CLUSTER
101366558b73STim Chen	bool "Cluster scheduler support"
101466558b73STim Chen	depends on SMP
101566558b73STim Chen	default y
101666558b73STim Chen	help
101766558b73STim Chen	  Cluster scheduler support improves the CPU scheduler's decision
101866558b73STim Chen	  making when dealing with machines that have clusters of CPUs.
101966558b73STim Chen	  Cluster usually means a couple of CPUs which are placed closely
102066558b73STim Chen	  by sharing mid-level caches, last-level cache tags or internal
102166558b73STim Chen	  busses.
102266558b73STim Chen
1023506f1d07SSam Ravnborgconfig SCHED_SMT
1024dbe73364SThomas Gleixner	def_bool y if SMP
1025506f1d07SSam Ravnborg
1026506f1d07SSam Ravnborgconfig SCHED_MC
10273c2362e6SHarvey Harrison	def_bool y
10283c2362e6SHarvey Harrison	prompt "Multi-core scheduler support"
1029c8e56d20SBorislav Petkov	depends on SMP
1030a7f7f624SMasahiro Yamada	help
1031506f1d07SSam Ravnborg	  Multi-core scheduler support improves the CPU scheduler's decision
1032506f1d07SSam Ravnborg	  making when dealing with multi-core CPU chips at a cost of slightly
1033506f1d07SSam Ravnborg	  increased overhead in some places. If unsure say N here.
1034506f1d07SSam Ravnborg
1035de966cf4STim Chenconfig SCHED_MC_PRIO
1036de966cf4STim Chen	bool "CPU core priorities scheduler support"
10370a21fc12SIngo Molnar	depends on SCHED_MC && CPU_SUP_INTEL
10380a21fc12SIngo Molnar	select X86_INTEL_PSTATE
10390a21fc12SIngo Molnar	select CPU_FREQ
1040de966cf4STim Chen	default y
1041a7f7f624SMasahiro Yamada	help
1042de966cf4STim Chen	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1043de966cf4STim Chen	  core ordering determined at manufacturing time, which allows
1044de966cf4STim Chen	  certain cores to reach higher turbo frequencies (when running
1045de966cf4STim Chen	  single threaded workloads) than others.
1046de966cf4STim Chen
1047de966cf4STim Chen	  Enabling this kernel feature teaches the scheduler about
1048de966cf4STim Chen	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1049de966cf4STim Chen	  scheduler's CPU selection logic accordingly, so that higher
1050de966cf4STim Chen	  overall system performance can be achieved.
1051de966cf4STim Chen
1052de966cf4STim Chen	  This feature will have no effect on CPUs without this feature.
1053de966cf4STim Chen
1054de966cf4STim Chen	  If unsure say Y here.
10555e76b2abSTim Chen
105630b8b006SThomas Gleixnerconfig UP_LATE_INIT
105730b8b006SThomas Gleixner	def_bool y
1058ba360f88SThomas Gleixner	depends on !SMP && X86_LOCAL_APIC
105930b8b006SThomas Gleixner
1060506f1d07SSam Ravnborgconfig X86_UP_APIC
106150849eefSJan Beulich	bool "Local APIC support on uniprocessors" if !PCI_MSI
106250849eefSJan Beulich	default PCI_MSI
106338a1dfdaSBryan O'Donoghue	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1064a7f7f624SMasahiro Yamada	help
1065506f1d07SSam Ravnborg	  A local APIC (Advanced Programmable Interrupt Controller) is an
1066506f1d07SSam Ravnborg	  integrated interrupt controller in the CPU. If you have a single-CPU
1067506f1d07SSam Ravnborg	  system which has a processor with a local APIC, you can say Y here to
1068506f1d07SSam Ravnborg	  enable and use it. If you say Y here even though your machine doesn't
1069506f1d07SSam Ravnborg	  have a local APIC, then the kernel will still run with no slowdown at
1070506f1d07SSam Ravnborg	  all. The local APIC supports CPU-generated self-interrupts (timer,
1071506f1d07SSam Ravnborg	  performance counters), and the NMI watchdog which detects hard
1072506f1d07SSam Ravnborg	  lockups.
1073506f1d07SSam Ravnborg
1074506f1d07SSam Ravnborgconfig X86_UP_IOAPIC
1075506f1d07SSam Ravnborg	bool "IO-APIC support on uniprocessors"
1076506f1d07SSam Ravnborg	depends on X86_UP_APIC
1077a7f7f624SMasahiro Yamada	help
1078506f1d07SSam Ravnborg	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1079506f1d07SSam Ravnborg	  SMP-capable replacement for PC-style interrupt controllers. Most
1080506f1d07SSam Ravnborg	  SMP systems and many recent uniprocessor systems have one.
1081506f1d07SSam Ravnborg
1082506f1d07SSam Ravnborg	  If you have a single-CPU system with an IO-APIC, you can say Y here
1083506f1d07SSam Ravnborg	  to use it. If you say Y here even though your machine doesn't have
1084506f1d07SSam Ravnborg	  an IO-APIC, then the kernel will still run with no slowdown at all.
1085506f1d07SSam Ravnborg
1086506f1d07SSam Ravnborgconfig X86_LOCAL_APIC
10873c2362e6SHarvey Harrison	def_bool y
10880dbc6078SThomas Petazzoni	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1089b5dc8e6cSJiang Liu	select IRQ_DOMAIN_HIERARCHY
109052f518a3SJiang Liu	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1091506f1d07SSam Ravnborg
1092506f1d07SSam Ravnborgconfig X86_IO_APIC
1093b1da1e71SJan Beulich	def_bool y
1094b1da1e71SJan Beulich	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1095506f1d07SSam Ravnborg
109641b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS
109741b9eb26SStefan Assmann	bool "Reroute for broken boot IRQs"
109841b9eb26SStefan Assmann	depends on X86_IO_APIC
1099a7f7f624SMasahiro Yamada	help
110041b9eb26SStefan Assmann	  This option enables a workaround that fixes a source of
110141b9eb26SStefan Assmann	  spurious interrupts. This is recommended when threaded
110241b9eb26SStefan Assmann	  interrupt handling is used on systems where the generation of
110341b9eb26SStefan Assmann	  superfluous "boot interrupts" cannot be disabled.
110441b9eb26SStefan Assmann
110541b9eb26SStefan Assmann	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
110641b9eb26SStefan Assmann	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
110741b9eb26SStefan Assmann	  kernel does during interrupt handling). On chipsets where this
110841b9eb26SStefan Assmann	  boot IRQ generation cannot be disabled, this workaround keeps
110941b9eb26SStefan Assmann	  the original IRQ line masked so that only the equivalent "boot
111041b9eb26SStefan Assmann	  IRQ" is delivered to the CPUs. The workaround also tells the
111141b9eb26SStefan Assmann	  kernel to set up the IRQ handler on the boot IRQ line. In this
111241b9eb26SStefan Assmann	  way only one interrupt is delivered to the kernel. Otherwise
111341b9eb26SStefan Assmann	  the spurious second interrupt may cause the kernel to bring
111441b9eb26SStefan Assmann	  down (vital) interrupt lines.
111541b9eb26SStefan Assmann
111641b9eb26SStefan Assmann	  Only affects "broken" chipsets. Interrupt sharing may be
111741b9eb26SStefan Assmann	  increased on these systems.
111841b9eb26SStefan Assmann
1119506f1d07SSam Ravnborgconfig X86_MCE
1120bab9bc65SAndi Kleen	bool "Machine Check / overheating reporting"
1121648ed940SChen, Gong	select GENERIC_ALLOCATOR
1122e57dbaf7SBorislav Petkov	default y
1123a7f7f624SMasahiro Yamada	help
1124bab9bc65SAndi Kleen	  Machine Check support allows the processor to notify the
1125bab9bc65SAndi Kleen	  kernel if it detects a problem (e.g. overheating, data corruption).
1126506f1d07SSam Ravnborg	  The action the kernel takes depends on the severity of the problem,
1127bab9bc65SAndi Kleen	  ranging from warning messages to halting the machine.
11284efc0670SAndi Kleen
11295de97c9fSTony Luckconfig X86_MCELOG_LEGACY
11305de97c9fSTony Luck	bool "Support for deprecated /dev/mcelog character device"
11315de97c9fSTony Luck	depends on X86_MCE
1132a7f7f624SMasahiro Yamada	help
11335de97c9fSTony Luck	  Enable support for /dev/mcelog which is needed by the old mcelog
11345de97c9fSTony Luck	  userspace logging daemon. Consider switching to the new generation
11355de97c9fSTony Luck	  rasdaemon solution.
11365de97c9fSTony Luck
1137506f1d07SSam Ravnborgconfig X86_MCE_INTEL
11383c2362e6SHarvey Harrison	def_bool y
11393c2362e6SHarvey Harrison	prompt "Intel MCE features"
1140c1ebf835SAndi Kleen	depends on X86_MCE && X86_LOCAL_APIC
1141a7f7f624SMasahiro Yamada	help
1142506f1d07SSam Ravnborg	   Additional support for intel specific MCE features such as
1143506f1d07SSam Ravnborg	   the thermal monitor.
1144506f1d07SSam Ravnborg
1145506f1d07SSam Ravnborgconfig X86_MCE_AMD
11463c2362e6SHarvey Harrison	def_bool y
11473c2362e6SHarvey Harrison	prompt "AMD MCE features"
1148f5382de9SYazen Ghannam	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1149a7f7f624SMasahiro Yamada	help
1150506f1d07SSam Ravnborg	   Additional support for AMD specific MCE features such as
1151506f1d07SSam Ravnborg	   the DRAM Error Threshold.
1152506f1d07SSam Ravnborg
11534efc0670SAndi Kleenconfig X86_ANCIENT_MCE
11546fc108a0SJan Beulich	bool "Support for old Pentium 5 / WinChip machine checks"
1155c31d9633SAndi Kleen	depends on X86_32 && X86_MCE
1156a7f7f624SMasahiro Yamada	help
11574efc0670SAndi Kleen	  Include support for machine check handling on old Pentium 5 or WinChip
11585065a706SMasanari Iida	  systems. These typically need to be enabled explicitly on the command
11594efc0670SAndi Kleen	  line.
11604efc0670SAndi Kleen
1161b2762686SAndi Kleenconfig X86_MCE_THRESHOLD
1162b2762686SAndi Kleen	depends on X86_MCE_AMD || X86_MCE_INTEL
11636fc108a0SJan Beulich	def_bool y
1164b2762686SAndi Kleen
1165ea149b36SAndi Kleenconfig X86_MCE_INJECT
1166bc8e80d5SBorislav Petkov	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1167ea149b36SAndi Kleen	tristate "Machine check injector support"
1168a7f7f624SMasahiro Yamada	help
1169ea149b36SAndi Kleen	  Provide support for injecting machine checks for testing purposes.
1170ea149b36SAndi Kleen	  If you don't know what a machine check is and you don't do kernel
1171ea149b36SAndi Kleen	  QA it is safe to say n.
1172ea149b36SAndi Kleen
117307dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig"
1174e633c65aSKan Liang
11755aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86
11761e642812SIngo Molnar	bool "Legacy VM86 support"
1177506f1d07SSam Ravnborg	depends on X86_32
1178a7f7f624SMasahiro Yamada	help
11795aef51c3SAndy Lutomirski	  This option allows user programs to put the CPU into V8086
11805aef51c3SAndy Lutomirski	  mode, which is an 80286-era approximation of 16-bit real mode.
11815aef51c3SAndy Lutomirski
11825aef51c3SAndy Lutomirski	  Some very old versions of X and/or vbetool require this option
11835aef51c3SAndy Lutomirski	  for user mode setting.  Similarly, DOSEMU will use it if
11845aef51c3SAndy Lutomirski	  available to accelerate real mode DOS programs.  However, any
11855aef51c3SAndy Lutomirski	  recent version of DOSEMU, X, or vbetool should be fully
11865aef51c3SAndy Lutomirski	  functional even without kernel VM86 support, as they will all
11871e642812SIngo Molnar	  fall back to software emulation. Nevertheless, if you are using
11881e642812SIngo Molnar	  a 16-bit DOS program where 16-bit performance matters, vm86
11891e642812SIngo Molnar	  mode might be faster than emulation and you might want to
11901e642812SIngo Molnar	  enable this option.
11915aef51c3SAndy Lutomirski
11921e642812SIngo Molnar	  Note that any app that works on a 64-bit kernel is unlikely to
11931e642812SIngo Molnar	  need this option, as 64-bit kernels don't, and can't, support
11941e642812SIngo Molnar	  V8086 mode. This option is also unrelated to 16-bit protected
11951e642812SIngo Molnar	  mode and is not needed to run most 16-bit programs under Wine.
11965aef51c3SAndy Lutomirski
11971e642812SIngo Molnar	  Enabling this option increases the complexity of the kernel
11981e642812SIngo Molnar	  and slows down exception handling a tiny bit.
11995aef51c3SAndy Lutomirski
12001e642812SIngo Molnar	  If unsure, say N here.
12015aef51c3SAndy Lutomirski
12025aef51c3SAndy Lutomirskiconfig VM86
12035aef51c3SAndy Lutomirski	bool
12045aef51c3SAndy Lutomirski	default X86_LEGACY_VM86
120534273f41SH. Peter Anvin
120634273f41SH. Peter Anvinconfig X86_16BIT
120734273f41SH. Peter Anvin	bool "Enable support for 16-bit segments" if EXPERT
120834273f41SH. Peter Anvin	default y
1209a5b9e5a2SAndy Lutomirski	depends on MODIFY_LDT_SYSCALL
1210a7f7f624SMasahiro Yamada	help
121134273f41SH. Peter Anvin	  This option is required by programs like Wine to run 16-bit
121234273f41SH. Peter Anvin	  protected mode legacy code on x86 processors.  Disabling
121334273f41SH. Peter Anvin	  this option saves about 300 bytes on i386, or around 6K text
121434273f41SH. Peter Anvin	  plus 16K runtime memory on x86-64,
121534273f41SH. Peter Anvin
121634273f41SH. Peter Anvinconfig X86_ESPFIX32
121734273f41SH. Peter Anvin	def_bool y
121834273f41SH. Peter Anvin	depends on X86_16BIT && X86_32
1219506f1d07SSam Ravnborg
1220197725deSH. Peter Anvinconfig X86_ESPFIX64
1221197725deSH. Peter Anvin	def_bool y
122234273f41SH. Peter Anvin	depends on X86_16BIT && X86_64
1223506f1d07SSam Ravnborg
12241ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION
12251ad83c85SAndy Lutomirski	bool "Enable vsyscall emulation" if EXPERT
12261ad83c85SAndy Lutomirski	default y
12271ad83c85SAndy Lutomirski	depends on X86_64
1228a7f7f624SMasahiro Yamada	help
12291ad83c85SAndy Lutomirski	 This enables emulation of the legacy vsyscall page.  Disabling
12301ad83c85SAndy Lutomirski	 it is roughly equivalent to booting with vsyscall=none, except
12311ad83c85SAndy Lutomirski	 that it will also disable the helpful warning if a program
12321ad83c85SAndy Lutomirski	 tries to use a vsyscall.  With this option set to N, offending
12331ad83c85SAndy Lutomirski	 programs will just segfault, citing addresses of the form
12341ad83c85SAndy Lutomirski	 0xffffffffff600?00.
12351ad83c85SAndy Lutomirski
12361ad83c85SAndy Lutomirski	 This option is required by many programs built before 2013, and
12371ad83c85SAndy Lutomirski	 care should be used even with newer programs if set to N.
12381ad83c85SAndy Lutomirski
12391ad83c85SAndy Lutomirski	 Disabling this option saves about 7K of kernel size and
12401ad83c85SAndy Lutomirski	 possibly 4K of additional runtime pagetable memory.
12411ad83c85SAndy Lutomirski
1242111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM
1243111e7b15SThomas Gleixner	bool "IOPERM and IOPL Emulation"
1244a24ca997SThomas Gleixner	default y
1245a7f7f624SMasahiro Yamada	help
1246111e7b15SThomas Gleixner	  This enables the ioperm() and iopl() syscalls which are necessary
1247111e7b15SThomas Gleixner	  for legacy applications.
1248111e7b15SThomas Gleixner
1249c8137aceSThomas Gleixner	  Legacy IOPL support is an overbroad mechanism which allows user
1250c8137aceSThomas Gleixner	  space aside of accessing all 65536 I/O ports also to disable
1251c8137aceSThomas Gleixner	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1252c8137aceSThomas Gleixner	  capabilities and permission from potentially active security
1253c8137aceSThomas Gleixner	  modules.
1254c8137aceSThomas Gleixner
1255c8137aceSThomas Gleixner	  The emulation restricts the functionality of the syscall to
1256c8137aceSThomas Gleixner	  only allowing the full range I/O port access, but prevents the
1257a24ca997SThomas Gleixner	  ability to disable interrupts from user space which would be
1258a24ca997SThomas Gleixner	  granted if the hardware IOPL mechanism would be used.
1259c8137aceSThomas Gleixner
1260506f1d07SSam Ravnborgconfig TOSHIBA
1261506f1d07SSam Ravnborg	tristate "Toshiba Laptop support"
1262506f1d07SSam Ravnborg	depends on X86_32
1263a7f7f624SMasahiro Yamada	help
1264506f1d07SSam Ravnborg	  This adds a driver to safely access the System Management Mode of
1265506f1d07SSam Ravnborg	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1266506f1d07SSam Ravnborg	  not work on models with a Phoenix BIOS. The System Management Mode
1267506f1d07SSam Ravnborg	  is used to set the BIOS and power saving options on Toshiba portables.
1268506f1d07SSam Ravnborg
1269506f1d07SSam Ravnborg	  For information on utilities to make use of this driver see the
1270506f1d07SSam Ravnborg	  Toshiba Linux utilities web site at:
1271506f1d07SSam Ravnborg	  <http://www.buzzard.org.uk/toshiba/>.
1272506f1d07SSam Ravnborg
1273506f1d07SSam Ravnborg	  Say Y if you intend to run this kernel on a Toshiba portable.
1274506f1d07SSam Ravnborg	  Say N otherwise.
1275506f1d07SSam Ravnborg
1276506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS
12779ba16087SJan Beulich	bool "Enable X86 board specific fixups for reboot"
12789ba16087SJan Beulich	depends on X86_32
1279a7f7f624SMasahiro Yamada	help
1280506f1d07SSam Ravnborg	  This enables chipset and/or board specific fixups to be done
1281506f1d07SSam Ravnborg	  in order to get reboot to work correctly. This is only needed on
1282506f1d07SSam Ravnborg	  some combinations of hardware and BIOS. The symptom, for which
1283506f1d07SSam Ravnborg	  this config is intended, is when reboot ends with a stalled/hung
1284506f1d07SSam Ravnborg	  system.
1285506f1d07SSam Ravnborg
1286506f1d07SSam Ravnborg	  Currently, the only fixup is for the Geode machines using
12875e3a77e9SFlorian Fainelli	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1288506f1d07SSam Ravnborg
1289506f1d07SSam Ravnborg	  Say Y if you want to enable the fixup. Currently, it's safe to
1290506f1d07SSam Ravnborg	  enable this option even if you don't need it.
1291506f1d07SSam Ravnborg	  Say N otherwise.
1292506f1d07SSam Ravnborg
1293506f1d07SSam Ravnborgconfig MICROCODE
12949a2bc335SBorislav Petkov	bool "CPU microcode loading support"
12959a2bc335SBorislav Petkov	default y
129680030e3dSBorislav Petkov	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1297a7f7f624SMasahiro Yamada	help
1298506f1d07SSam Ravnborg	  If you say Y here, you will be able to update the microcode on
12995f9c01aaSBorislav Petkov	  Intel and AMD processors. The Intel support is for the IA32 family,
13005f9c01aaSBorislav Petkov	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
13015f9c01aaSBorislav Petkov	  AMD support is for families 0x10 and later. You will obviously need
13025f9c01aaSBorislav Petkov	  the actual microcode binary data itself which is not shipped with
13035f9c01aaSBorislav Petkov	  the Linux kernel.
1304506f1d07SSam Ravnborg
13055f9c01aaSBorislav Petkov	  The preferred method to load microcode from a detached initrd is described
1306cb1aaebeSMauro Carvalho Chehab	  in Documentation/x86/microcode.rst. For that you need to enable
13075f9c01aaSBorislav Petkov	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
13085f9c01aaSBorislav Petkov	  initrd for microcode blobs.
1309506f1d07SSam Ravnborg
1310c508c46eSBenjamin Gilbert	  In addition, you can build the microcode into the kernel. For that you
1311c508c46eSBenjamin Gilbert	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1312c508c46eSBenjamin Gilbert	  config option.
1313506f1d07SSam Ravnborg
13148d86f390SPeter Orubaconfig MICROCODE_INTEL
1315e43f6e67SBorislav Petkov	bool "Intel microcode loading support"
13168d86f390SPeter Oruba	depends on MICROCODE
13178d86f390SPeter Oruba	default MICROCODE
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
1329a7f7f624SMasahiro Yamada	help
133080cc9f10SPeter Oruba	  If you select this option, microcode patch loading support for AMD
133180cc9f10SPeter Oruba	  processors will be enabled.
133280cc9f10SPeter Oruba
1333506f1d07SSam Ravnborgconfig MICROCODE_OLD_INTERFACE
1334c02f48e0SBorislav Petkov	bool "Ancient loading interface (DEPRECATED)"
1335c02f48e0SBorislav Petkov	default n
1336506f1d07SSam Ravnborg	depends on MICROCODE
1337a7f7f624SMasahiro Yamada	help
1338c02f48e0SBorislav Petkov	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1339c02f48e0SBorislav Petkov	  which was used by userspace tools like iucode_tool and microcode.ctl.
1340c02f48e0SBorislav Petkov	  It is inadequate because it runs too late to be able to properly
1341c02f48e0SBorislav Petkov	  load microcode on a machine and it needs special tools. Instead, you
1342c02f48e0SBorislav Petkov	  should've switched to the early loading method with the initrd or
1343cb1aaebeSMauro Carvalho Chehab	  builtin microcode by now: Documentation/x86/microcode.rst
1344506f1d07SSam Ravnborg
1345506f1d07SSam Ravnborgconfig X86_MSR
1346506f1d07SSam Ravnborg	tristate "/dev/cpu/*/msr - Model-specific register support"
1347a7f7f624SMasahiro Yamada	help
1348506f1d07SSam Ravnborg	  This device gives privileged processes access to the x86
1349506f1d07SSam Ravnborg	  Model-Specific Registers (MSRs).  It is a character device with
1350506f1d07SSam Ravnborg	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1351506f1d07SSam Ravnborg	  MSR accesses are directed to a specific CPU on multi-processor
1352506f1d07SSam Ravnborg	  systems.
1353506f1d07SSam Ravnborg
1354506f1d07SSam Ravnborgconfig X86_CPUID
1355506f1d07SSam Ravnborg	tristate "/dev/cpu/*/cpuid - CPU information support"
1356a7f7f624SMasahiro Yamada	help
1357506f1d07SSam Ravnborg	  This device gives processes access to the x86 CPUID instruction to
1358506f1d07SSam Ravnborg	  be executed on a specific processor.  It is a character device
1359506f1d07SSam Ravnborg	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1360506f1d07SSam Ravnborg	  /dev/cpu/31/cpuid.
1361506f1d07SSam Ravnborg
1362506f1d07SSam Ravnborgchoice
1363506f1d07SSam Ravnborg	prompt "High Memory Support"
13646fc108a0SJan Beulich	default HIGHMEM4G
1365506f1d07SSam Ravnborg	depends on X86_32
1366506f1d07SSam Ravnborg
1367506f1d07SSam Ravnborgconfig NOHIGHMEM
1368506f1d07SSam Ravnborg	bool "off"
1369a7f7f624SMasahiro Yamada	help
1370506f1d07SSam Ravnborg	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1371506f1d07SSam Ravnborg	  However, the address space of 32-bit x86 processors is only 4
1372506f1d07SSam Ravnborg	  Gigabytes large. That means that, if you have a large amount of
1373506f1d07SSam Ravnborg	  physical memory, not all of it can be "permanently mapped" by the
1374506f1d07SSam Ravnborg	  kernel. The physical memory that's not permanently mapped is called
1375506f1d07SSam Ravnborg	  "high memory".
1376506f1d07SSam Ravnborg
1377506f1d07SSam Ravnborg	  If you are compiling a kernel which will never run on a machine with
1378506f1d07SSam Ravnborg	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1379506f1d07SSam Ravnborg	  choice and suitable for most users). This will result in a "3GB/1GB"
1380506f1d07SSam Ravnborg	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1381506f1d07SSam Ravnborg	  space and the remaining part of the 4GB virtual memory space is used
1382506f1d07SSam Ravnborg	  by the kernel to permanently map as much physical memory as
1383506f1d07SSam Ravnborg	  possible.
1384506f1d07SSam Ravnborg
1385506f1d07SSam Ravnborg	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1386506f1d07SSam Ravnborg	  answer "4GB" here.
1387506f1d07SSam Ravnborg
1388506f1d07SSam Ravnborg	  If more than 4 Gigabytes is used then answer "64GB" here. This
1389506f1d07SSam Ravnborg	  selection turns Intel PAE (Physical Address Extension) mode on.
1390506f1d07SSam Ravnborg	  PAE implements 3-level paging on IA32 processors. PAE is fully
1391506f1d07SSam Ravnborg	  supported by Linux, PAE mode is implemented on all recent Intel
1392506f1d07SSam Ravnborg	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1393506f1d07SSam Ravnborg	  then the kernel will not boot on CPUs that don't support PAE!
1394506f1d07SSam Ravnborg
1395506f1d07SSam Ravnborg	  The actual amount of total physical memory will either be
1396506f1d07SSam Ravnborg	  auto detected or can be forced by using a kernel command line option
1397506f1d07SSam Ravnborg	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1398506f1d07SSam Ravnborg	  your boot loader (lilo or loadlin) about how to pass options to the
1399506f1d07SSam Ravnborg	  kernel at boot time.)
1400506f1d07SSam Ravnborg
1401506f1d07SSam Ravnborg	  If unsure, say "off".
1402506f1d07SSam Ravnborg
1403506f1d07SSam Ravnborgconfig HIGHMEM4G
1404506f1d07SSam Ravnborg	bool "4GB"
1405a7f7f624SMasahiro Yamada	help
1406506f1d07SSam Ravnborg	  Select this if you have a 32-bit processor and between 1 and 4
1407506f1d07SSam Ravnborg	  gigabytes of physical RAM.
1408506f1d07SSam Ravnborg
1409506f1d07SSam Ravnborgconfig HIGHMEM64G
1410506f1d07SSam Ravnborg	bool "64GB"
1411225bac2dSLukas Bulwahn	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1412506f1d07SSam Ravnborg	select X86_PAE
1413a7f7f624SMasahiro Yamada	help
1414506f1d07SSam Ravnborg	  Select this if you have a 32-bit processor and more than 4
1415506f1d07SSam Ravnborg	  gigabytes of physical RAM.
1416506f1d07SSam Ravnborg
1417506f1d07SSam Ravnborgendchoice
1418506f1d07SSam Ravnborg
1419506f1d07SSam Ravnborgchoice
14206a108a14SDavid Rientjes	prompt "Memory split" if EXPERT
1421506f1d07SSam Ravnborg	default VMSPLIT_3G
1422506f1d07SSam Ravnborg	depends on X86_32
1423a7f7f624SMasahiro Yamada	help
1424506f1d07SSam Ravnborg	  Select the desired split between kernel and user memory.
1425506f1d07SSam Ravnborg
1426506f1d07SSam Ravnborg	  If the address range available to the kernel is less than the
1427506f1d07SSam Ravnborg	  physical memory installed, the remaining memory will be available
1428506f1d07SSam Ravnborg	  as "high memory". Accessing high memory is a little more costly
1429506f1d07SSam Ravnborg	  than low memory, as it needs to be mapped into the kernel first.
1430506f1d07SSam Ravnborg	  Note that increasing the kernel address space limits the range
1431506f1d07SSam Ravnborg	  available to user programs, making the address space there
1432506f1d07SSam Ravnborg	  tighter.  Selecting anything other than the default 3G/1G split
1433506f1d07SSam Ravnborg	  will also likely make your kernel incompatible with binary-only
1434506f1d07SSam Ravnborg	  kernel modules.
1435506f1d07SSam Ravnborg
1436506f1d07SSam Ravnborg	  If you are not absolutely sure what you are doing, leave this
1437506f1d07SSam Ravnborg	  option alone!
1438506f1d07SSam Ravnborg
1439506f1d07SSam Ravnborg	config VMSPLIT_3G
1440506f1d07SSam Ravnborg		bool "3G/1G user/kernel split"
1441506f1d07SSam Ravnborg	config VMSPLIT_3G_OPT
1442506f1d07SSam Ravnborg		depends on !X86_PAE
1443506f1d07SSam Ravnborg		bool "3G/1G user/kernel split (for full 1G low memory)"
1444506f1d07SSam Ravnborg	config VMSPLIT_2G
1445506f1d07SSam Ravnborg		bool "2G/2G user/kernel split"
1446506f1d07SSam Ravnborg	config VMSPLIT_2G_OPT
1447506f1d07SSam Ravnborg		depends on !X86_PAE
1448506f1d07SSam Ravnborg		bool "2G/2G user/kernel split (for full 2G low memory)"
1449506f1d07SSam Ravnborg	config VMSPLIT_1G
1450506f1d07SSam Ravnborg		bool "1G/3G user/kernel split"
1451506f1d07SSam Ravnborgendchoice
1452506f1d07SSam Ravnborg
1453506f1d07SSam Ravnborgconfig PAGE_OFFSET
1454506f1d07SSam Ravnborg	hex
1455506f1d07SSam Ravnborg	default 0xB0000000 if VMSPLIT_3G_OPT
1456506f1d07SSam Ravnborg	default 0x80000000 if VMSPLIT_2G
1457506f1d07SSam Ravnborg	default 0x78000000 if VMSPLIT_2G_OPT
1458506f1d07SSam Ravnborg	default 0x40000000 if VMSPLIT_1G
1459506f1d07SSam Ravnborg	default 0xC0000000
1460506f1d07SSam Ravnborg	depends on X86_32
1461506f1d07SSam Ravnborg
1462506f1d07SSam Ravnborgconfig HIGHMEM
14633c2362e6SHarvey Harrison	def_bool y
1464506f1d07SSam Ravnborg	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1465506f1d07SSam Ravnborg
1466506f1d07SSam Ravnborgconfig X86_PAE
14679ba16087SJan Beulich	bool "PAE (Physical Address Extension) Support"
1468506f1d07SSam Ravnborg	depends on X86_32 && !HIGHMEM4G
1469d4a451d5SChristoph Hellwig	select PHYS_ADDR_T_64BIT
14709d99c712SChristian Melki	select SWIOTLB
1471a7f7f624SMasahiro Yamada	help
1472506f1d07SSam Ravnborg	  PAE is required for NX support, and furthermore enables
1473506f1d07SSam Ravnborg	  larger swapspace support for non-overcommit purposes. It
1474506f1d07SSam Ravnborg	  has the cost of more pagetable lookup overhead, and also
1475506f1d07SSam Ravnborg	  consumes more pagetable space per process.
1476506f1d07SSam Ravnborg
147777ef56e4SKirill A. Shutemovconfig X86_5LEVEL
147877ef56e4SKirill A. Shutemov	bool "Enable 5-level page tables support"
147918ec1eafSKirill A. Shutemov	default y
1480eedb92abSKirill A. Shutemov	select DYNAMIC_MEMORY_LAYOUT
1481162434e7SKirill A. Shutemov	select SPARSEMEM_VMEMMAP
148277ef56e4SKirill A. Shutemov	depends on X86_64
1483a7f7f624SMasahiro Yamada	help
148477ef56e4SKirill A. Shutemov	  5-level paging enables access to larger address space:
148577ef56e4SKirill A. Shutemov	  upto 128 PiB of virtual address space and 4 PiB of
148677ef56e4SKirill A. Shutemov	  physical address space.
148777ef56e4SKirill A. Shutemov
148877ef56e4SKirill A. Shutemov	  It will be supported by future Intel CPUs.
148977ef56e4SKirill A. Shutemov
14906657fca0SKirill A. Shutemov	  A kernel with the option enabled can be booted on machines that
14916657fca0SKirill A. Shutemov	  support 4- or 5-level paging.
149277ef56e4SKirill A. Shutemov
1493cb1aaebeSMauro Carvalho Chehab	  See Documentation/x86/x86_64/5level-paging.rst for more
149477ef56e4SKirill A. Shutemov	  information.
149577ef56e4SKirill A. Shutemov
149677ef56e4SKirill A. Shutemov	  Say N if unsure.
149777ef56e4SKirill A. Shutemov
149810971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES
1499e5008abeSLuis R. Rodriguez	def_bool y
15002e1da13fSVlastimil Babka	depends on X86_64
1501a7f7f624SMasahiro Yamada	help
150210971ab2SIngo Molnar	  Certain kernel features effectively disable kernel
150310971ab2SIngo Molnar	  linear 1 GB mappings (even if the CPU otherwise
150410971ab2SIngo Molnar	  supports them), so don't confuse the user by printing
150510971ab2SIngo Molnar	  that we have them enabled.
15069e899816SNick Piggin
15075c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS
15085c280cf6SThomas Gleixner	bool "Enable statistic for Change Page Attribute"
15095c280cf6SThomas Gleixner	depends on DEBUG_FS
1510a7f7f624SMasahiro Yamada	help
1511b75baaf3SIngo Molnar	  Expose statistics about the Change Page Attribute mechanism, which
1512a943245aSColin Ian King	  helps to determine the effectiveness of preserving large and huge
15135c280cf6SThomas Gleixner	  page mappings when mapping protections are changed.
15145c280cf6SThomas Gleixner
151520f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT
151620f07a04SKirill A. Shutemov	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
151720f07a04SKirill A. Shutemov	select DYNAMIC_PHYSICAL_MASK
151820f07a04SKirill A. Shutemov	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
151920f07a04SKirill A. Shutemov	def_bool n
152020f07a04SKirill A. Shutemov
15217744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT
15227744ccdbSTom Lendacky	bool "AMD Secure Memory Encryption (SME) support"
15237744ccdbSTom Lendacky	depends on X86_64 && CPU_SUP_AMD
152482fef0adSDavid Rientjes	select DMA_COHERENT_POOL
1525ce9084baSArd Biesheuvel	select ARCH_USE_MEMREMAP_PROT
1526597cfe48SJoerg Roedel	select INSTRUCTION_DECODER
1527aa5a4611STom Lendacky	select ARCH_HAS_CC_PLATFORM
152820f07a04SKirill A. Shutemov	select X86_MEM_ENCRYPT
1529a7f7f624SMasahiro Yamada	help
15307744ccdbSTom Lendacky	  Say yes to enable support for the encryption of system memory.
15317744ccdbSTom Lendacky	  This requires an AMD processor that supports Secure Memory
15327744ccdbSTom Lendacky	  Encryption (SME).
15337744ccdbSTom Lendacky
15347744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
15357744ccdbSTom Lendacky	bool "Activate AMD Secure Memory Encryption (SME) by default"
15367744ccdbSTom Lendacky	depends on AMD_MEM_ENCRYPT
1537a7f7f624SMasahiro Yamada	help
15387744ccdbSTom Lendacky	  Say yes to have system memory encrypted by default if running on
15397744ccdbSTom Lendacky	  an AMD processor that supports Secure Memory Encryption (SME).
15407744ccdbSTom Lendacky
15417744ccdbSTom Lendacky	  If set to Y, then the encryption of system memory can be
15427744ccdbSTom Lendacky	  deactivated with the mem_encrypt=off command line option.
15437744ccdbSTom Lendacky
15447744ccdbSTom Lendacky	  If set to N, then the encryption of system memory can be
15457744ccdbSTom Lendacky	  activated with the mem_encrypt=on command line option.
15467744ccdbSTom Lendacky
1547506f1d07SSam Ravnborg# Common NUMA Features
1548506f1d07SSam Ravnborgconfig NUMA
1549e133f6eaSRandy Dunlap	bool "NUMA Memory Allocation and Scheduler Support"
1550506f1d07SSam Ravnborg	depends on SMP
1551b5660ba7SH. Peter Anvin	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1552b5660ba7SH. Peter Anvin	default y if X86_BIGSMP
15537ecd19cfSKefeng Wang	select USE_PERCPU_NUMA_NODE_ID
1554a7f7f624SMasahiro Yamada	help
1555e133f6eaSRandy Dunlap	  Enable NUMA (Non-Uniform Memory Access) support.
1556fd51b2d7SKOSAKI Motohiro
1557506f1d07SSam Ravnborg	  The kernel will try to allocate memory used by a CPU on the
1558506f1d07SSam Ravnborg	  local memory controller of the CPU and add some more
1559506f1d07SSam Ravnborg	  NUMA awareness to the kernel.
1560506f1d07SSam Ravnborg
1561c280ea5eSIngo Molnar	  For 64-bit this is recommended if the system is Intel Core i7
1562fd51b2d7SKOSAKI Motohiro	  (or later), AMD Opteron, or EM64T NUMA.
1563fd51b2d7SKOSAKI Motohiro
1564b5660ba7SH. Peter Anvin	  For 32-bit this is only needed if you boot a 32-bit
15657cf6c945SDavid Rientjes	  kernel on a 64-bit NUMA platform.
1566fd51b2d7SKOSAKI Motohiro
1567fd51b2d7SKOSAKI Motohiro	  Otherwise, you should say N.
1568506f1d07SSam Ravnborg
1569eec1d4faSHans Rosenfeldconfig AMD_NUMA
15703c2362e6SHarvey Harrison	def_bool y
15713c2362e6SHarvey Harrison	prompt "Old style AMD Opteron NUMA detection"
15725da0ef9aSTejun Heo	depends on X86_64 && NUMA && PCI
1573a7f7f624SMasahiro Yamada	help
1574eec1d4faSHans Rosenfeld	  Enable AMD NUMA node topology detection.  You should say Y here if
1575eec1d4faSHans Rosenfeld	  you have a multi processor AMD system. This uses an old method to
1576eec1d4faSHans Rosenfeld	  read the NUMA configuration directly from the builtin Northbridge
1577eec1d4faSHans Rosenfeld	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1578eec1d4faSHans Rosenfeld	  which also takes priority if both are compiled in.
1579506f1d07SSam Ravnborg
1580506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA
15813c2362e6SHarvey Harrison	def_bool y
15823c2362e6SHarvey Harrison	prompt "ACPI NUMA detection"
1583506f1d07SSam Ravnborg	depends on X86_64 && NUMA && ACPI && PCI
1584506f1d07SSam Ravnborg	select ACPI_NUMA
1585a7f7f624SMasahiro Yamada	help
1586506f1d07SSam Ravnborg	  Enable ACPI SRAT based node topology detection.
1587506f1d07SSam Ravnborg
1588506f1d07SSam Ravnborgconfig NUMA_EMU
1589506f1d07SSam Ravnborg	bool "NUMA emulation"
15901b7e03efSTejun Heo	depends on NUMA
1591a7f7f624SMasahiro Yamada	help
1592506f1d07SSam Ravnborg	  Enable NUMA emulation. A flat machine will be split
1593506f1d07SSam Ravnborg	  into virtual nodes when booted with "numa=fake=N", where N is the
1594506f1d07SSam Ravnborg	  number of nodes. This is only useful for debugging.
1595506f1d07SSam Ravnborg
1596506f1d07SSam Ravnborgconfig NODES_SHIFT
1597d25e26b6SLinus Torvalds	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
159851591e31SDavid Rientjes	range 1 10
159951591e31SDavid Rientjes	default "10" if MAXSMP
1600506f1d07SSam Ravnborg	default "6" if X86_64
1601506f1d07SSam Ravnborg	default "3"
1602a9ee6cf5SMike Rapoport	depends on NUMA
1603a7f7f624SMasahiro Yamada	help
16041184dc2fSMike Travis	  Specify the maximum number of NUMA Nodes available on the target
1605692105b8SMatt LaPlante	  system.  Increases memory reserved to accommodate various tables.
1606506f1d07SSam Ravnborg
1607506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE
1608506f1d07SSam Ravnborg	def_bool y
16093b16651fSTejun Heo	depends on X86_32 && !NUMA
1610506f1d07SSam Ravnborg
1611506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE
1612506f1d07SSam Ravnborg	def_bool y
16136ea30386SKees Cook	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1614506f1d07SSam Ravnborg	select SPARSEMEM_STATIC if X86_32
1615506f1d07SSam Ravnborg	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1616506f1d07SSam Ravnborg
16173b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT
16186ad57f7fSMike Rapoport	def_bool X86_64 || (NUMA && X86_32)
16193b16651fSTejun Heo
1620506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL
1621506f1d07SSam Ravnborg	def_bool y
16224eda2bc3SDavid Hildenbrand	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1623506f1d07SSam Ravnborg
1624506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE
1625a0842b70SToshi Kani	bool "Enable sysfs memory/probe interface"
16265c11f00bSDavid Hildenbrand	depends on MEMORY_HOTPLUG
1627a0842b70SToshi Kani	help
1628a0842b70SToshi Kani	  This option enables a sysfs memory/probe interface for testing.
1629cb1aaebeSMauro Carvalho Chehab	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1630a0842b70SToshi Kani	  If you are unsure how to answer this question, answer N.
1631506f1d07SSam Ravnborg
16323b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT
16333b16651fSTejun Heo	def_bool y
16343b16651fSTejun Heo	depends on X86_64 && PROC_KCORE
16353b16651fSTejun Heo
1636a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE
1637a29815a3SAvi Kivity	hex
1638a29815a3SAvi Kivity	default 0 if X86_32
1639a29815a3SAvi Kivity	default 0xdead000000000000 if X86_64
1640a29815a3SAvi Kivity
16417a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE
16427a67832cSDan Williams	bool
16437a67832cSDan Williams
1644ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY
16457a67832cSDan Williams	tristate "Support non-standard NVDIMMs and ADR protected memory"
16469f53f9faSDan Williams	depends on PHYS_ADDR_T_64BIT
16479f53f9faSDan Williams	depends on BLK_DEV
16487a67832cSDan Williams	select X86_PMEM_LEGACY_DEVICE
16497b27a862SDan Williams	select NUMA_KEEP_MEMINFO if NUMA
16509f53f9faSDan Williams	select LIBNVDIMM
1651ec776ef6SChristoph Hellwig	help
1652ec776ef6SChristoph Hellwig	  Treat memory marked using the non-standard e820 type of 12 as used
1653ec776ef6SChristoph Hellwig	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1654ec776ef6SChristoph Hellwig	  The kernel will offer these regions to the 'pmem' driver so
1655ec776ef6SChristoph Hellwig	  they can be used for persistent storage.
1656ec776ef6SChristoph Hellwig
1657ec776ef6SChristoph Hellwig	  Say Y if unsure.
1658ec776ef6SChristoph Hellwig
1659506f1d07SSam Ravnborgconfig HIGHPTE
1660506f1d07SSam Ravnborg	bool "Allocate 3rd-level pagetables from highmem"
16616fc108a0SJan Beulich	depends on HIGHMEM
1662a7f7f624SMasahiro Yamada	help
1663506f1d07SSam Ravnborg	  The VM uses one page table entry for each page of physical memory.
1664506f1d07SSam Ravnborg	  For systems with a lot of RAM, this can be wasteful of precious
1665506f1d07SSam Ravnborg	  low memory.  Setting this option will put user-space page table
1666506f1d07SSam Ravnborg	  entries in high memory.
1667506f1d07SSam Ravnborg
16689f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION
16699f077871SJeremy Fitzhardinge	bool "Check for low memory corruption"
1670a7f7f624SMasahiro Yamada	help
16719f077871SJeremy Fitzhardinge	  Periodically check for memory corruption in low memory, which
16729f077871SJeremy Fitzhardinge	  is suspected to be caused by BIOS.  Even when enabled in the
16739f077871SJeremy Fitzhardinge	  configuration, it is disabled at runtime.  Enable it by
16749f077871SJeremy Fitzhardinge	  setting "memory_corruption_check=1" on the kernel command
16759f077871SJeremy Fitzhardinge	  line.  By default it scans the low 64k of memory every 60
16769f077871SJeremy Fitzhardinge	  seconds; see the memory_corruption_check_size and
16779f077871SJeremy Fitzhardinge	  memory_corruption_check_period parameters in
16788c27ceffSMauro Carvalho Chehab	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
16799f077871SJeremy Fitzhardinge
16809f077871SJeremy Fitzhardinge	  When enabled with the default parameters, this option has
16819f077871SJeremy Fitzhardinge	  almost no overhead, as it reserves a relatively small amount
16829f077871SJeremy Fitzhardinge	  of memory and scans it infrequently.  It both detects corruption
16839f077871SJeremy Fitzhardinge	  and prevents it from affecting the running system.
16849f077871SJeremy Fitzhardinge
16859f077871SJeremy Fitzhardinge	  It is, however, intended as a diagnostic tool; if repeatable
16869f077871SJeremy Fitzhardinge	  BIOS-originated corruption always affects the same memory,
16879f077871SJeremy Fitzhardinge	  you can use memmap= to prevent the kernel from using that
16889f077871SJeremy Fitzhardinge	  memory.
16899f077871SJeremy Fitzhardinge
1690c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1691c885df50SJeremy Fitzhardinge	bool "Set the default setting of memory_corruption_check"
1692c885df50SJeremy Fitzhardinge	depends on X86_CHECK_BIOS_CORRUPTION
1693c885df50SJeremy Fitzhardinge	default y
1694a7f7f624SMasahiro Yamada	help
1695c885df50SJeremy Fitzhardinge	  Set whether the default state of memory_corruption_check is
1696c885df50SJeremy Fitzhardinge	  on or off.
1697c885df50SJeremy Fitzhardinge
1698506f1d07SSam Ravnborgconfig MATH_EMULATION
1699506f1d07SSam Ravnborg	bool
1700a5b9e5a2SAndy Lutomirski	depends on MODIFY_LDT_SYSCALL
170187d6021bSArnd Bergmann	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1702a7f7f624SMasahiro Yamada	help
1703506f1d07SSam Ravnborg	  Linux can emulate a math coprocessor (used for floating point
1704506f1d07SSam Ravnborg	  operations) if you don't have one. 486DX and Pentium processors have
1705506f1d07SSam Ravnborg	  a math coprocessor built in, 486SX and 386 do not, unless you added
1706506f1d07SSam Ravnborg	  a 487DX or 387, respectively. (The messages during boot time can
1707506f1d07SSam Ravnborg	  give you some hints here ["man dmesg"].) Everyone needs either a
1708506f1d07SSam Ravnborg	  coprocessor or this emulation.
1709506f1d07SSam Ravnborg
1710506f1d07SSam Ravnborg	  If you don't have a math coprocessor, you need to say Y here; if you
1711506f1d07SSam Ravnborg	  say Y here even though you have a coprocessor, the coprocessor will
1712506f1d07SSam Ravnborg	  be used nevertheless. (This behavior can be changed with the kernel
1713506f1d07SSam Ravnborg	  command line option "no387", which comes handy if your coprocessor
1714506f1d07SSam Ravnborg	  is broken. Try "man bootparam" or see the documentation of your boot
1715506f1d07SSam Ravnborg	  loader (lilo or loadlin) about how to pass options to the kernel at
1716506f1d07SSam Ravnborg	  boot time.) This means that it is a good idea to say Y here if you
1717506f1d07SSam Ravnborg	  intend to use this kernel on different machines.
1718506f1d07SSam Ravnborg
1719506f1d07SSam Ravnborg	  More information about the internals of the Linux math coprocessor
1720506f1d07SSam Ravnborg	  emulation can be found in <file:arch/x86/math-emu/README>.
1721506f1d07SSam Ravnborg
1722506f1d07SSam Ravnborg	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1723506f1d07SSam Ravnborg	  kernel, it won't hurt.
1724506f1d07SSam Ravnborg
1725506f1d07SSam Ravnborgconfig MTRR
17266fc108a0SJan Beulich	def_bool y
17276a108a14SDavid Rientjes	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1728a7f7f624SMasahiro Yamada	help
1729506f1d07SSam Ravnborg	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1730506f1d07SSam Ravnborg	  the Memory Type Range Registers (MTRRs) may be used to control
1731506f1d07SSam Ravnborg	  processor access to memory ranges. This is most useful if you have
1732506f1d07SSam Ravnborg	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1733506f1d07SSam Ravnborg	  allows bus write transfers to be combined into a larger transfer
1734506f1d07SSam Ravnborg	  before bursting over the PCI/AGP bus. This can increase performance
1735506f1d07SSam Ravnborg	  of image write operations 2.5 times or more. Saying Y here creates a
1736506f1d07SSam Ravnborg	  /proc/mtrr file which may be used to manipulate your processor's
1737506f1d07SSam Ravnborg	  MTRRs. Typically the X server should use this.
1738506f1d07SSam Ravnborg
1739506f1d07SSam Ravnborg	  This code has a reasonably generic interface so that similar
1740506f1d07SSam Ravnborg	  control registers on other processors can be easily supported
1741506f1d07SSam Ravnborg	  as well:
1742506f1d07SSam Ravnborg
1743506f1d07SSam Ravnborg	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1744506f1d07SSam Ravnborg	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1745506f1d07SSam Ravnborg	  these, the ARRs are used to emulate the MTRRs.
1746506f1d07SSam Ravnborg	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1747506f1d07SSam Ravnborg	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1748506f1d07SSam Ravnborg	  write-combining. All of these processors are supported by this code
1749506f1d07SSam Ravnborg	  and it makes sense to say Y here if you have one of them.
1750506f1d07SSam Ravnborg
1751506f1d07SSam Ravnborg	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1752506f1d07SSam Ravnborg	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1753506f1d07SSam Ravnborg	  can lead to all sorts of problems, so it's good to say Y here.
1754506f1d07SSam Ravnborg
1755506f1d07SSam Ravnborg	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1756506f1d07SSam Ravnborg	  just add about 9 KB to your kernel.
1757506f1d07SSam Ravnborg
1758cb1aaebeSMauro Carvalho Chehab	  See <file:Documentation/x86/mtrr.rst> for more information.
1759506f1d07SSam Ravnborg
176095ffa243SYinghai Luconfig MTRR_SANITIZER
17612ffb3501SYinghai Lu	def_bool y
176295ffa243SYinghai Lu	prompt "MTRR cleanup support"
176395ffa243SYinghai Lu	depends on MTRR
1764a7f7f624SMasahiro Yamada	help
1765aba3728cSThomas Gleixner	  Convert MTRR layout from continuous to discrete, so X drivers can
1766aba3728cSThomas Gleixner	  add writeback entries.
176795ffa243SYinghai Lu
1768aba3728cSThomas Gleixner	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1769692105b8SMatt LaPlante	  The largest mtrr entry size for a continuous block can be set with
1770aba3728cSThomas Gleixner	  mtrr_chunk_size.
177195ffa243SYinghai Lu
17722ffb3501SYinghai Lu	  If unsure, say Y.
177395ffa243SYinghai Lu
177495ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT
1775f5098d62SYinghai Lu	int "MTRR cleanup enable value (0-1)"
1776f5098d62SYinghai Lu	range 0 1
1777f5098d62SYinghai Lu	default "0"
177895ffa243SYinghai Lu	depends on MTRR_SANITIZER
1779a7f7f624SMasahiro Yamada	help
1780f5098d62SYinghai Lu	  Enable mtrr cleanup default value
178195ffa243SYinghai Lu
178212031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
178312031a62SYinghai Lu	int "MTRR cleanup spare reg num (0-7)"
178412031a62SYinghai Lu	range 0 7
178512031a62SYinghai Lu	default "1"
178612031a62SYinghai Lu	depends on MTRR_SANITIZER
1787a7f7f624SMasahiro Yamada	help
178812031a62SYinghai Lu	  mtrr cleanup spare entries default, it can be changed via
1789aba3728cSThomas Gleixner	  mtrr_spare_reg_nr=N on the kernel command line.
179012031a62SYinghai Lu
17912e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT
17926fc108a0SJan Beulich	def_bool y
17936a108a14SDavid Rientjes	prompt "x86 PAT support" if EXPERT
17942a8a2719SIngo Molnar	depends on MTRR
1795a7f7f624SMasahiro Yamada	help
17962e5d9c85Svenkatesh.pallipadi@intel.com	  Use PAT attributes to setup page level cache control.
1797042b78e4SVenki Pallipadi
17982e5d9c85Svenkatesh.pallipadi@intel.com	  PATs are the modern equivalents of MTRRs and are much more
17992e5d9c85Svenkatesh.pallipadi@intel.com	  flexible than MTRRs.
18002e5d9c85Svenkatesh.pallipadi@intel.com
18012e5d9c85Svenkatesh.pallipadi@intel.com	  Say N here if you see bootup problems (boot crash, boot hang,
1802042b78e4SVenki Pallipadi	  spontaneous reboots) or a non-working video driver.
18032e5d9c85Svenkatesh.pallipadi@intel.com
18042e5d9c85Svenkatesh.pallipadi@intel.com	  If unsure, say Y.
18052e5d9c85Svenkatesh.pallipadi@intel.com
180646cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED
180746cf98cdSVenkatesh Pallipadi	def_bool y
180846cf98cdSVenkatesh Pallipadi	depends on X86_PAT
180946cf98cdSVenkatesh Pallipadi
1810628c6246SH. Peter Anvinconfig ARCH_RANDOM
1811628c6246SH. Peter Anvin	def_bool y
1812628c6246SH. Peter Anvin	prompt "x86 architectural random number generator" if EXPERT
1813a7f7f624SMasahiro Yamada	help
1814628c6246SH. Peter Anvin	  Enable the x86 architectural RDRAND instruction
1815628c6246SH. Peter Anvin	  (Intel Bull Mountain technology) to generate random numbers.
1816628c6246SH. Peter Anvin	  If supported, this is a high bandwidth, cryptographically
1817628c6246SH. Peter Anvin	  secure hardware random number generator.
1818628c6246SH. Peter Anvin
181951ae4a2dSH. Peter Anvinconfig X86_SMAP
182051ae4a2dSH. Peter Anvin	def_bool y
182151ae4a2dSH. Peter Anvin	prompt "Supervisor Mode Access Prevention" if EXPERT
1822a7f7f624SMasahiro Yamada	help
182351ae4a2dSH. Peter Anvin	  Supervisor Mode Access Prevention (SMAP) is a security
182451ae4a2dSH. Peter Anvin	  feature in newer Intel processors.  There is a small
182551ae4a2dSH. Peter Anvin	  performance cost if this enabled and turned on; there is
182651ae4a2dSH. Peter Anvin	  also a small increase in the kernel size if this is enabled.
182751ae4a2dSH. Peter Anvin
182851ae4a2dSH. Peter Anvin	  If unsure, say Y.
182951ae4a2dSH. Peter Anvin
1830b971880fSBabu Mogerconfig X86_UMIP
1831796ebc81SRicardo Neri	def_bool y
1832b971880fSBabu Moger	prompt "User Mode Instruction Prevention" if EXPERT
1833a7f7f624SMasahiro Yamada	help
1834b971880fSBabu Moger	  User Mode Instruction Prevention (UMIP) is a security feature in
1835b971880fSBabu Moger	  some x86 processors. If enabled, a general protection fault is
1836b971880fSBabu Moger	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1837b971880fSBabu Moger	  executed in user mode. These instructions unnecessarily expose
1838b971880fSBabu Moger	  information about the hardware state.
1839796ebc81SRicardo Neri
1840796ebc81SRicardo Neri	  The vast majority of applications do not use these instructions.
1841796ebc81SRicardo Neri	  For the very few that do, software emulation is provided in
1842796ebc81SRicardo Neri	  specific cases in protected and virtual-8086 modes. Emulated
1843796ebc81SRicardo Neri	  results are dummy.
1844aa35f896SRicardo Neri
1845156ff4a5SPeter Zijlstraconfig CC_HAS_IBT
1846156ff4a5SPeter Zijlstra	# GCC >= 9 and binutils >= 2.29
1847156ff4a5SPeter Zijlstra	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1848156ff4a5SPeter Zijlstra	# Clang/LLVM >= 14
1849262448f3SNathan Chancellor	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1850262448f3SNathan Chancellor	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1851156ff4a5SPeter Zijlstra	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1852262448f3SNathan Chancellor		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1853156ff4a5SPeter Zijlstra		  $(as-instr,endbr64)
1854156ff4a5SPeter Zijlstra
1855156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT
1856156ff4a5SPeter Zijlstra	prompt "Indirect Branch Tracking"
1857156ff4a5SPeter Zijlstra	bool
1858ed53a0d9SPeter Zijlstra	depends on X86_64 && CC_HAS_IBT && STACK_VALIDATION
1859f6a2c2b2SNathan Chancellor	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1860f6a2c2b2SNathan Chancellor	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1861156ff4a5SPeter Zijlstra	help
1862156ff4a5SPeter Zijlstra	  Build the kernel with support for Indirect Branch Tracking, a
1863156ff4a5SPeter Zijlstra	  hardware support course-grain forward-edge Control Flow Integrity
1864156ff4a5SPeter Zijlstra	  protection. It enforces that all indirect calls must land on
1865156ff4a5SPeter Zijlstra	  an ENDBR instruction, as such, the compiler will instrument the
1866156ff4a5SPeter Zijlstra	  code with them to make this happen.
1867156ff4a5SPeter Zijlstra
1868ed53a0d9SPeter Zijlstra	  In addition to building the kernel with IBT, seal all functions that
18694cdfc11bSNur Hussein	  are not indirect call targets, avoiding them ever becoming one.
1870ed53a0d9SPeter Zijlstra
1871ed53a0d9SPeter Zijlstra	  This requires LTO like objtool runs and will slow down the build. It
1872ed53a0d9SPeter Zijlstra	  does significantly reduce the number of ENDBR instructions in the
1873ed53a0d9SPeter Zijlstra	  kernel image.
1874ed53a0d9SPeter Zijlstra
187535e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS
187638f3e775SBabu Moger	prompt "Memory Protection Keys"
187735e97790SDave Hansen	def_bool y
1878284244a9SDave Hansen	# Note: only available in 64-bit mode
187938f3e775SBabu Moger	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
188052c8e601SIngo Molnar	select ARCH_USES_HIGH_VMA_FLAGS
188152c8e601SIngo Molnar	select ARCH_HAS_PKEYS
1882a7f7f624SMasahiro Yamada	help
1883284244a9SDave Hansen	  Memory Protection Keys provides a mechanism for enforcing
1884284244a9SDave Hansen	  page-based protections, but without requiring modification of the
1885284244a9SDave Hansen	  page tables when an application changes protection domains.
1886284244a9SDave Hansen
18871eecbcdcSMauro Carvalho Chehab	  For details, see Documentation/core-api/protection-keys.rst
1888284244a9SDave Hansen
1889284244a9SDave Hansen	  If unsure, say y.
189035e97790SDave Hansen
1891db616173SMichal Hockochoice
1892db616173SMichal Hocko	prompt "TSX enable mode"
1893db616173SMichal Hocko	depends on CPU_SUP_INTEL
1894db616173SMichal Hocko	default X86_INTEL_TSX_MODE_OFF
1895db616173SMichal Hocko	help
1896db616173SMichal Hocko	  Intel's TSX (Transactional Synchronization Extensions) feature
1897db616173SMichal Hocko	  allows to optimize locking protocols through lock elision which
1898db616173SMichal Hocko	  can lead to a noticeable performance boost.
1899db616173SMichal Hocko
1900db616173SMichal Hocko	  On the other hand it has been shown that TSX can be exploited
1901db616173SMichal Hocko	  to form side channel attacks (e.g. TAA) and chances are there
1902db616173SMichal Hocko	  will be more of those attacks discovered in the future.
1903db616173SMichal Hocko
1904db616173SMichal Hocko	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1905db616173SMichal Hocko	  might override this decision by tsx=on the command line parameter.
1906db616173SMichal Hocko	  Even with TSX enabled, the kernel will attempt to enable the best
1907db616173SMichal Hocko	  possible TAA mitigation setting depending on the microcode available
1908db616173SMichal Hocko	  for the particular machine.
1909db616173SMichal Hocko
1910db616173SMichal Hocko	  This option allows to set the default tsx mode between tsx=on, =off
1911db616173SMichal Hocko	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1912db616173SMichal Hocko	  details.
1913db616173SMichal Hocko
1914db616173SMichal Hocko	  Say off if not sure, auto if TSX is in use but it should be used on safe
1915db616173SMichal Hocko	  platforms or on if TSX is in use and the security aspect of tsx is not
1916db616173SMichal Hocko	  relevant.
1917db616173SMichal Hocko
1918db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF
1919db616173SMichal Hocko	bool "off"
1920db616173SMichal Hocko	help
1921db616173SMichal Hocko	  TSX is disabled if possible - equals to tsx=off command line parameter.
1922db616173SMichal Hocko
1923db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON
1924db616173SMichal Hocko	bool "on"
1925db616173SMichal Hocko	help
1926db616173SMichal Hocko	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1927db616173SMichal Hocko	  line parameter.
1928db616173SMichal Hocko
1929db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO
1930db616173SMichal Hocko	bool "auto"
1931db616173SMichal Hocko	help
1932db616173SMichal Hocko	  TSX is enabled on TSX capable HW that is believed to be safe against
1933db616173SMichal Hocko	  side channel attacks- equals the tsx=auto command line parameter.
1934db616173SMichal Hockoendchoice
1935db616173SMichal Hocko
1936e7e05452SSean Christophersonconfig X86_SGX
1937e7e05452SSean Christopherson	bool "Software Guard eXtensions (SGX)"
1938e7e05452SSean Christopherson	depends on X86_64 && CPU_SUP_INTEL
1939e7e05452SSean Christopherson	depends on CRYPTO=y
1940e7e05452SSean Christopherson	depends on CRYPTO_SHA256=y
1941e7e05452SSean Christopherson	select SRCU
1942e7e05452SSean Christopherson	select MMU_NOTIFIER
1943901ddbb9SJarkko Sakkinen	select NUMA_KEEP_MEMINFO if NUMA
194440e0e784STony Luck	select XARRAY_MULTI
1945e7e05452SSean Christopherson	help
1946e7e05452SSean Christopherson	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1947e7e05452SSean Christopherson	  that can be used by applications to set aside private regions of code
1948e7e05452SSean Christopherson	  and data, referred to as enclaves. An enclave's private memory can
1949e7e05452SSean Christopherson	  only be accessed by code running within the enclave. Accesses from
1950e7e05452SSean Christopherson	  outside the enclave, including other enclaves, are disallowed by
1951e7e05452SSean Christopherson	  hardware.
1952e7e05452SSean Christopherson
1953e7e05452SSean Christopherson	  If unsure, say N.
1954e7e05452SSean Christopherson
1955506f1d07SSam Ravnborgconfig EFI
19569ba16087SJan Beulich	bool "EFI runtime service support"
19575b83683fSHuang, Ying	depends on ACPI
1958f6ce5002SSergey Vlasov	select UCS2_STRING
1959022ee6c5SArd Biesheuvel	select EFI_RUNTIME_WRAPPERS
19601ff2fc02STom Lendacky	select ARCH_USE_MEMREMAP_PROT
1961a7f7f624SMasahiro Yamada	help
19628b2cb7a8SHuang, Ying	  This enables the kernel to use EFI runtime services that are
1963506f1d07SSam Ravnborg	  available (such as the EFI variable services).
1964506f1d07SSam Ravnborg
19658b2cb7a8SHuang, Ying	  This option is only useful on systems that have EFI firmware.
19668b2cb7a8SHuang, Ying	  In addition, you should use the latest ELILO loader available
19678b2cb7a8SHuang, Ying	  at <http://elilo.sourceforge.net> in order to take advantage
19688b2cb7a8SHuang, Ying	  of EFI runtime services. However, even with this option, the
19698b2cb7a8SHuang, Ying	  resultant kernel should continue to boot on existing non-EFI
19708b2cb7a8SHuang, Ying	  platforms.
1971506f1d07SSam Ravnborg
1972291f3632SMatt Flemingconfig EFI_STUB
1973291f3632SMatt Fleming	bool "EFI stub support"
1974c6dbd3e5SPeter Zijlstra	depends on EFI
19758f24f8c2SArd Biesheuvel	depends on $(cc-option,-mabi=ms) || X86_32
19767b2a583aSMatt Fleming	select RELOCATABLE
1977a7f7f624SMasahiro Yamada	help
1978291f3632SMatt Fleming	  This kernel feature allows a bzImage to be loaded directly
1979291f3632SMatt Fleming	  by EFI firmware without the use of a bootloader.
1980291f3632SMatt Fleming
19814f4cfa6cSMauro Carvalho Chehab	  See Documentation/admin-guide/efi-stub.rst for more information.
19820c759662SMatt Fleming
19837d453eeeSMatt Flemingconfig EFI_MIXED
19847d453eeeSMatt Fleming	bool "EFI mixed-mode support"
19857d453eeeSMatt Fleming	depends on EFI_STUB && X86_64
1986a7f7f624SMasahiro Yamada	help
19877d453eeeSMatt Fleming	   Enabling this feature allows a 64-bit kernel to be booted
19887d453eeeSMatt Fleming	   on a 32-bit firmware, provided that your CPU supports 64-bit
19897d453eeeSMatt Fleming	   mode.
19907d453eeeSMatt Fleming
19917d453eeeSMatt Fleming	   Note that it is not possible to boot a mixed-mode enabled
19927d453eeeSMatt Fleming	   kernel via the EFI boot stub - a bootloader that supports
19937d453eeeSMatt Fleming	   the EFI handover protocol must be used.
19947d453eeeSMatt Fleming
19957d453eeeSMatt Fleming	   If unsure, say N.
19967d453eeeSMatt Fleming
19978636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz"
1998506f1d07SSam Ravnborg
1999506f1d07SSam Ravnborgconfig KEXEC
2000506f1d07SSam Ravnborg	bool "kexec system call"
20012965faa5SDave Young	select KEXEC_CORE
2002a7f7f624SMasahiro Yamada	help
2003506f1d07SSam Ravnborg	  kexec is a system call that implements the ability to shutdown your
2004506f1d07SSam Ravnborg	  current kernel, and to start another kernel.  It is like a reboot
2005506f1d07SSam Ravnborg	  but it is independent of the system firmware.   And like a reboot
2006506f1d07SSam Ravnborg	  you can start any kernel with it, not just Linux.
2007506f1d07SSam Ravnborg
2008506f1d07SSam Ravnborg	  The name comes from the similarity to the exec system call.
2009506f1d07SSam Ravnborg
2010506f1d07SSam Ravnborg	  It is an ongoing process to be certain the hardware in a machine
2011506f1d07SSam Ravnborg	  is properly shutdown, so do not be surprised if this code does not
2012bf220695SGeert Uytterhoeven	  initially work for you.  As of this writing the exact hardware
2013bf220695SGeert Uytterhoeven	  interface is strongly in flux, so no good recommendation can be
2014bf220695SGeert Uytterhoeven	  made.
2015506f1d07SSam Ravnborg
201674ca317cSVivek Goyalconfig KEXEC_FILE
201774ca317cSVivek Goyal	bool "kexec file based system call"
20182965faa5SDave Young	select KEXEC_CORE
201974ca317cSVivek Goyal	select BUILD_BIN2C
202074ca317cSVivek Goyal	depends on X86_64
202174ca317cSVivek Goyal	depends on CRYPTO=y
202274ca317cSVivek Goyal	depends on CRYPTO_SHA256=y
2023a7f7f624SMasahiro Yamada	help
202474ca317cSVivek Goyal	  This is new version of kexec system call. This system call is
202574ca317cSVivek Goyal	  file based and takes file descriptors as system call argument
202674ca317cSVivek Goyal	  for kernel and initramfs as opposed to list of segments as
202774ca317cSVivek Goyal	  accepted by previous system call.
202874ca317cSVivek Goyal
2029b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY
2030b799a09fSAKASHI Takahiro	def_bool KEXEC_FILE
2031b799a09fSAKASHI Takahiro
203299d5cadfSJiri Bohacconfig KEXEC_SIG
20338e7d8381SVivek Goyal	bool "Verify kernel signature during kexec_file_load() syscall"
203474ca317cSVivek Goyal	depends on KEXEC_FILE
2035a7f7f624SMasahiro Yamada	help
203699d5cadfSJiri Bohac
203799d5cadfSJiri Bohac	  This option makes the kexec_file_load() syscall check for a valid
203899d5cadfSJiri Bohac	  signature of the kernel image.  The image can still be loaded without
203999d5cadfSJiri Bohac	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
204099d5cadfSJiri Bohac	  there's a signature that we can check, then it must be valid.
204199d5cadfSJiri Bohac
204299d5cadfSJiri Bohac	  In addition to this option, you need to enable signature
204399d5cadfSJiri Bohac	  verification for the corresponding kernel image type being
204499d5cadfSJiri Bohac	  loaded in order for this to work.
204599d5cadfSJiri Bohac
204699d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE
204799d5cadfSJiri Bohac	bool "Require a valid signature in kexec_file_load() syscall"
204899d5cadfSJiri Bohac	depends on KEXEC_SIG
2049a7f7f624SMasahiro Yamada	help
20508e7d8381SVivek Goyal	  This option makes kernel signature verification mandatory for
2051d8eb8940SBorislav Petkov	  the kexec_file_load() syscall.
20528e7d8381SVivek Goyal
20538e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG
20548e7d8381SVivek Goyal	bool "Enable bzImage signature verification support"
205599d5cadfSJiri Bohac	depends on KEXEC_SIG
20568e7d8381SVivek Goyal	depends on SIGNED_PE_FILE_VERIFICATION
20578e7d8381SVivek Goyal	select SYSTEM_TRUSTED_KEYRING
2058a7f7f624SMasahiro Yamada	help
20598e7d8381SVivek Goyal	  Enable bzImage signature verification support.
20608e7d8381SVivek Goyal
2061506f1d07SSam Ravnborgconfig CRASH_DUMP
206204b69447SPavel Machek	bool "kernel crash dumps"
2063506f1d07SSam Ravnborg	depends on X86_64 || (X86_32 && HIGHMEM)
2064a7f7f624SMasahiro Yamada	help
2065506f1d07SSam Ravnborg	  Generate crash dump after being started by kexec.
2066506f1d07SSam Ravnborg	  This should be normally only set in special crash dump kernels
2067506f1d07SSam Ravnborg	  which are loaded in the main kernel with kexec-tools into
2068506f1d07SSam Ravnborg	  a specially reserved region and then later executed after
2069506f1d07SSam Ravnborg	  a crash by kdump/kexec. The crash dump kernel must be compiled
2070506f1d07SSam Ravnborg	  to a memory address not used by the main kernel or BIOS using
2071506f1d07SSam Ravnborg	  PHYSICAL_START, or it must be built as a relocatable image
2072506f1d07SSam Ravnborg	  (CONFIG_RELOCATABLE=y).
2073330d4810SMauro Carvalho Chehab	  For more details see Documentation/admin-guide/kdump/kdump.rst
2074506f1d07SSam Ravnborg
20753ab83521SHuang Yingconfig KEXEC_JUMP
20766ea30386SKees Cook	bool "kexec jump"
2077fee7b0d8SHuang Ying	depends on KEXEC && HIBERNATION
2078a7f7f624SMasahiro Yamada	help
207989081d17SHuang Ying	  Jump between original kernel and kexeced kernel and invoke
208089081d17SHuang Ying	  code in physical address mode via KEXEC
20813ab83521SHuang Ying
2082506f1d07SSam Ravnborgconfig PHYSICAL_START
20836a108a14SDavid Rientjes	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2084ceefccc9SH. Peter Anvin	default "0x1000000"
2085a7f7f624SMasahiro Yamada	help
2086506f1d07SSam Ravnborg	  This gives the physical address where the kernel is loaded.
2087506f1d07SSam Ravnborg
2088506f1d07SSam Ravnborg	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2089506f1d07SSam Ravnborg	  bzImage will decompress itself to above physical address and
2090506f1d07SSam Ravnborg	  run from there. Otherwise, bzImage will run from the address where
2091506f1d07SSam Ravnborg	  it has been loaded by the boot loader and will ignore above physical
2092506f1d07SSam Ravnborg	  address.
2093506f1d07SSam Ravnborg
2094506f1d07SSam Ravnborg	  In normal kdump cases one does not have to set/change this option
2095506f1d07SSam Ravnborg	  as now bzImage can be compiled as a completely relocatable image
2096506f1d07SSam Ravnborg	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2097506f1d07SSam Ravnborg	  address. This option is mainly useful for the folks who don't want
2098506f1d07SSam Ravnborg	  to use a bzImage for capturing the crash dump and want to use a
2099506f1d07SSam Ravnborg	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2100506f1d07SSam Ravnborg	  to be specifically compiled to run from a specific memory area
2101506f1d07SSam Ravnborg	  (normally a reserved region) and this option comes handy.
2102506f1d07SSam Ravnborg
2103ceefccc9SH. Peter Anvin	  So if you are using bzImage for capturing the crash dump,
2104ceefccc9SH. Peter Anvin	  leave the value here unchanged to 0x1000000 and set
2105ceefccc9SH. Peter Anvin	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2106ceefccc9SH. Peter Anvin	  for capturing the crash dump change this value to start of
2107ceefccc9SH. Peter Anvin	  the reserved region.  In other words, it can be set based on
2108ceefccc9SH. Peter Anvin	  the "X" value as specified in the "crashkernel=YM@XM"
2109ceefccc9SH. Peter Anvin	  command line boot parameter passed to the panic-ed
2110330d4810SMauro Carvalho Chehab	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2111ceefccc9SH. Peter Anvin	  for more details about crash dumps.
2112506f1d07SSam Ravnborg
2113506f1d07SSam Ravnborg	  Usage of bzImage for capturing the crash dump is recommended as
2114506f1d07SSam Ravnborg	  one does not have to build two kernels. Same kernel can be used
2115506f1d07SSam Ravnborg	  as production kernel and capture kernel. Above option should have
2116506f1d07SSam Ravnborg	  gone away after relocatable bzImage support is introduced. But it
2117506f1d07SSam Ravnborg	  is present because there are users out there who continue to use
2118506f1d07SSam Ravnborg	  vmlinux for dump capture. This option should go away down the
2119506f1d07SSam Ravnborg	  line.
2120506f1d07SSam Ravnborg
2121506f1d07SSam Ravnborg	  Don't change this unless you know what you are doing.
2122506f1d07SSam Ravnborg
2123506f1d07SSam Ravnborgconfig RELOCATABLE
212426717808SH. Peter Anvin	bool "Build a relocatable kernel"
212526717808SH. Peter Anvin	default y
2126a7f7f624SMasahiro Yamada	help
2127506f1d07SSam Ravnborg	  This builds a kernel image that retains relocation information
2128506f1d07SSam Ravnborg	  so it can be loaded someplace besides the default 1MB.
2129506f1d07SSam Ravnborg	  The relocations tend to make the kernel binary about 10% larger,
2130506f1d07SSam Ravnborg	  but are discarded at runtime.
2131506f1d07SSam Ravnborg
2132506f1d07SSam Ravnborg	  One use is for the kexec on panic case where the recovery kernel
2133506f1d07SSam Ravnborg	  must live at a different physical address than the primary
2134506f1d07SSam Ravnborg	  kernel.
2135506f1d07SSam Ravnborg
2136506f1d07SSam Ravnborg	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2137506f1d07SSam Ravnborg	  it has been loaded at and the compile time physical address
21388ab3820fSKees Cook	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2139506f1d07SSam Ravnborg
21408ab3820fSKees Cookconfig RANDOMIZE_BASE
2141e8581e3dSBaoquan He	bool "Randomize the address of the kernel image (KASLR)"
21428ab3820fSKees Cook	depends on RELOCATABLE
21436807c846SIngo Molnar	default y
2144a7f7f624SMasahiro Yamada	help
2145e8581e3dSBaoquan He	  In support of Kernel Address Space Layout Randomization (KASLR),
2146e8581e3dSBaoquan He	  this randomizes the physical address at which the kernel image
2147e8581e3dSBaoquan He	  is decompressed and the virtual address where the kernel
2148e8581e3dSBaoquan He	  image is mapped, as a security feature that deters exploit
2149e8581e3dSBaoquan He	  attempts relying on knowledge of the location of kernel
2150e8581e3dSBaoquan He	  code internals.
2151e8581e3dSBaoquan He
2152ed9f007eSKees Cook	  On 64-bit, the kernel physical and virtual addresses are
2153ed9f007eSKees Cook	  randomized separately. The physical address will be anywhere
2154ed9f007eSKees Cook	  between 16MB and the top of physical memory (up to 64TB). The
2155ed9f007eSKees Cook	  virtual address will be randomized from 16MB up to 1GB (9 bits
2156ed9f007eSKees Cook	  of entropy). Note that this also reduces the memory space
2157ed9f007eSKees Cook	  available to kernel modules from 1.5GB to 1GB.
2158ed9f007eSKees Cook
2159ed9f007eSKees Cook	  On 32-bit, the kernel physical and virtual addresses are
2160ed9f007eSKees Cook	  randomized together. They will be randomized from 16MB up to
2161ed9f007eSKees Cook	  512MB (8 bits of entropy).
21628ab3820fSKees Cook
2163a653f356SKees Cook	  Entropy is generated using the RDRAND instruction if it is
2164e8581e3dSBaoquan He	  supported. If RDTSC is supported, its value is mixed into
2165e8581e3dSBaoquan He	  the entropy pool as well. If neither RDRAND nor RDTSC are
2166ed9f007eSKees Cook	  supported, then entropy is read from the i8254 timer. The
2167ed9f007eSKees Cook	  usable entropy is limited by the kernel being built using
2168ed9f007eSKees Cook	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2169ed9f007eSKees Cook	  minimum of 2MB. As a result, only 10 bits of entropy are
2170ed9f007eSKees Cook	  theoretically possible, but the implementations are further
2171ed9f007eSKees Cook	  limited due to memory layouts.
2172e8581e3dSBaoquan He
21736807c846SIngo Molnar	  If unsure, say Y.
2174da2b6fb9SKees Cook
21758ab3820fSKees Cook# Relocation on x86 needs some additional build support
2176845adf72SH. Peter Anvinconfig X86_NEED_RELOCS
2177845adf72SH. Peter Anvin	def_bool y
21788ab3820fSKees Cook	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2179845adf72SH. Peter Anvin
2180506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN
2181a0215061SKees Cook	hex "Alignment value to which kernel should be aligned"
21828ab3820fSKees Cook	default "0x200000"
2183a0215061SKees Cook	range 0x2000 0x1000000 if X86_32
2184a0215061SKees Cook	range 0x200000 0x1000000 if X86_64
2185a7f7f624SMasahiro Yamada	help
2186506f1d07SSam Ravnborg	  This value puts the alignment restrictions on physical address
2187506f1d07SSam Ravnborg	  where kernel is loaded and run from. Kernel is compiled for an
2188506f1d07SSam Ravnborg	  address which meets above alignment restriction.
2189506f1d07SSam Ravnborg
2190506f1d07SSam Ravnborg	  If bootloader loads the kernel at a non-aligned address and
2191506f1d07SSam Ravnborg	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2192506f1d07SSam Ravnborg	  address aligned to above value and run from there.
2193506f1d07SSam Ravnborg
2194506f1d07SSam Ravnborg	  If bootloader loads the kernel at a non-aligned address and
2195506f1d07SSam Ravnborg	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2196506f1d07SSam Ravnborg	  load address and decompress itself to the address it has been
2197506f1d07SSam Ravnborg	  compiled for and run from there. The address for which kernel is
2198506f1d07SSam Ravnborg	  compiled already meets above alignment restrictions. Hence the
2199506f1d07SSam Ravnborg	  end result is that kernel runs from a physical address meeting
2200506f1d07SSam Ravnborg	  above alignment restrictions.
2201506f1d07SSam Ravnborg
2202a0215061SKees Cook	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2203a0215061SKees Cook	  this value must be a multiple of 0x200000.
2204a0215061SKees Cook
2205506f1d07SSam Ravnborg	  Don't change this unless you know what you are doing.
2206506f1d07SSam Ravnborg
2207eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT
2208eedb92abSKirill A. Shutemov	bool
2209a7f7f624SMasahiro Yamada	help
2210eedb92abSKirill A. Shutemov	  This option makes base addresses of vmalloc and vmemmap as well as
2211eedb92abSKirill A. Shutemov	  __PAGE_OFFSET movable during boot.
2212eedb92abSKirill A. Shutemov
22130483e1faSThomas Garnierconfig RANDOMIZE_MEMORY
22140483e1faSThomas Garnier	bool "Randomize the kernel memory sections"
22150483e1faSThomas Garnier	depends on X86_64
22160483e1faSThomas Garnier	depends on RANDOMIZE_BASE
2217eedb92abSKirill A. Shutemov	select DYNAMIC_MEMORY_LAYOUT
22180483e1faSThomas Garnier	default RANDOMIZE_BASE
2219a7f7f624SMasahiro Yamada	help
22200483e1faSThomas Garnier	   Randomizes the base virtual address of kernel memory sections
22210483e1faSThomas Garnier	   (physical memory mapping, vmalloc & vmemmap). This security feature
22220483e1faSThomas Garnier	   makes exploits relying on predictable memory locations less reliable.
22230483e1faSThomas Garnier
22240483e1faSThomas Garnier	   The order of allocations remains unchanged. Entropy is generated in
22250483e1faSThomas Garnier	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
22260483e1faSThomas Garnier	   configuration have in average 30,000 different possible virtual
22270483e1faSThomas Garnier	   addresses for each memory section.
22280483e1faSThomas Garnier
22296807c846SIngo Molnar	   If unsure, say Y.
22300483e1faSThomas Garnier
223190397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING
223290397a41SThomas Garnier	hex "Physical memory mapping padding" if EXPERT
223390397a41SThomas Garnier	depends on RANDOMIZE_MEMORY
223490397a41SThomas Garnier	default "0xa" if MEMORY_HOTPLUG
223590397a41SThomas Garnier	default "0x0"
223690397a41SThomas Garnier	range 0x1 0x40 if MEMORY_HOTPLUG
223790397a41SThomas Garnier	range 0x0 0x40
2238a7f7f624SMasahiro Yamada	help
223990397a41SThomas Garnier	   Define the padding in terabytes added to the existing physical
224090397a41SThomas Garnier	   memory size during kernel memory randomization. It is useful
224190397a41SThomas Garnier	   for memory hotplug support but reduces the entropy available for
224290397a41SThomas Garnier	   address randomization.
224390397a41SThomas Garnier
224490397a41SThomas Garnier	   If unsure, leave at the default value.
224590397a41SThomas Garnier
2246506f1d07SSam Ravnborgconfig HOTPLUG_CPU
2247bebd024eSThomas Gleixner	def_bool y
224840b31360SStephen Rothwell	depends on SMP
2249506f1d07SSam Ravnborg
225080aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0
225180aa1dffSFenghua Yu	bool "Set default setting of cpu0_hotpluggable"
22522c922cd0SKees Cook	depends on HOTPLUG_CPU
2253a7f7f624SMasahiro Yamada	help
225480aa1dffSFenghua Yu	  Set whether default state of cpu0_hotpluggable is on or off.
225580aa1dffSFenghua Yu
225680aa1dffSFenghua Yu	  Say Y here to enable CPU0 hotplug by default. If this switch
225780aa1dffSFenghua Yu	  is turned on, there is no need to give cpu0_hotplug kernel
225880aa1dffSFenghua Yu	  parameter and the CPU0 hotplug feature is enabled by default.
225980aa1dffSFenghua Yu
226080aa1dffSFenghua Yu	  Please note: there are two known CPU0 dependencies if you want
226180aa1dffSFenghua Yu	  to enable the CPU0 hotplug feature either by this switch or by
226280aa1dffSFenghua Yu	  cpu0_hotplug kernel parameter.
226380aa1dffSFenghua Yu
226480aa1dffSFenghua Yu	  First, resume from hibernate or suspend always starts from CPU0.
226580aa1dffSFenghua Yu	  So hibernate and suspend are prevented if CPU0 is offline.
226680aa1dffSFenghua Yu
226780aa1dffSFenghua Yu	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
226880aa1dffSFenghua Yu	  offline if any interrupt can not migrate out of CPU0. There may
226980aa1dffSFenghua Yu	  be other CPU0 dependencies.
227080aa1dffSFenghua Yu
227180aa1dffSFenghua Yu	  Please make sure the dependencies are under your control before
227280aa1dffSFenghua Yu	  you enable this feature.
227380aa1dffSFenghua Yu
227480aa1dffSFenghua Yu	  Say N if you don't want to enable CPU0 hotplug feature by default.
227580aa1dffSFenghua Yu	  You still can enable the CPU0 hotplug feature at boot by kernel
227680aa1dffSFenghua Yu	  parameter cpu0_hotplug.
227780aa1dffSFenghua Yu
2278a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0
2279a71c8bc5SFenghua Yu	def_bool n
2280a71c8bc5SFenghua Yu	prompt "Debug CPU0 hotplug"
22812c922cd0SKees Cook	depends on HOTPLUG_CPU
2282a7f7f624SMasahiro Yamada	help
2283a71c8bc5SFenghua Yu	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2284a71c8bc5SFenghua Yu	  soon as possible and boots up userspace with CPU0 offlined. User
2285a71c8bc5SFenghua Yu	  can online CPU0 back after boot time.
2286a71c8bc5SFenghua Yu
2287a71c8bc5SFenghua Yu	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2288a71c8bc5SFenghua Yu	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2289a71c8bc5SFenghua Yu	  compilation or giving cpu0_hotplug kernel parameter at boot.
2290a71c8bc5SFenghua Yu
2291a71c8bc5SFenghua Yu	  If unsure, say N.
2292a71c8bc5SFenghua Yu
2293506f1d07SSam Ravnborgconfig COMPAT_VDSO
2294b0b49f26SAndy Lutomirski	def_bool n
2295b0b49f26SAndy Lutomirski	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2296953fee1dSIngo Molnar	depends on COMPAT_32
2297a7f7f624SMasahiro Yamada	help
2298b0b49f26SAndy Lutomirski	  Certain buggy versions of glibc will crash if they are
2299b0b49f26SAndy Lutomirski	  presented with a 32-bit vDSO that is not mapped at the address
2300b0b49f26SAndy Lutomirski	  indicated in its segment table.
2301e84446deSRandy Dunlap
2302b0b49f26SAndy Lutomirski	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2303b0b49f26SAndy Lutomirski	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2304b0b49f26SAndy Lutomirski	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2305b0b49f26SAndy Lutomirski	  the only released version with the bug, but OpenSUSE 9
2306b0b49f26SAndy Lutomirski	  contains a buggy "glibc 2.3.2".
2307506f1d07SSam Ravnborg
2308b0b49f26SAndy Lutomirski	  The symptom of the bug is that everything crashes on startup, saying:
2309b0b49f26SAndy Lutomirski	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2310b0b49f26SAndy Lutomirski
2311b0b49f26SAndy Lutomirski	  Saying Y here changes the default value of the vdso32 boot
2312b0b49f26SAndy Lutomirski	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2313b0b49f26SAndy Lutomirski	  This works around the glibc bug but hurts performance.
2314b0b49f26SAndy Lutomirski
2315b0b49f26SAndy Lutomirski	  If unsure, say N: if you are compiling your own kernel, you
2316b0b49f26SAndy Lutomirski	  are unlikely to be using a buggy version of glibc.
2317506f1d07SSam Ravnborg
23183dc33bd3SKees Cookchoice
23193dc33bd3SKees Cook	prompt "vsyscall table for legacy applications"
23203dc33bd3SKees Cook	depends on X86_64
2321625b7b7fSAndy Lutomirski	default LEGACY_VSYSCALL_XONLY
23223dc33bd3SKees Cook	help
23233dc33bd3SKees Cook	  Legacy user code that does not know how to find the vDSO expects
23243dc33bd3SKees Cook	  to be able to issue three syscalls by calling fixed addresses in
23253dc33bd3SKees Cook	  kernel space. Since this location is not randomized with ASLR,
23263dc33bd3SKees Cook	  it can be used to assist security vulnerability exploitation.
23273dc33bd3SKees Cook
23283dc33bd3SKees Cook	  This setting can be changed at boot time via the kernel command
2329*bf00745eSAndy Lutomirski	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2330*bf00745eSAndy Lutomirski	  is deprecated and can only be enabled using the kernel command
2331*bf00745eSAndy Lutomirski	  line.
23323dc33bd3SKees Cook
23333dc33bd3SKees Cook	  On a system with recent enough glibc (2.14 or newer) and no
23343dc33bd3SKees Cook	  static binaries, you can say None without a performance penalty
23353dc33bd3SKees Cook	  to improve security.
23363dc33bd3SKees Cook
2337bd49e16eSAndy Lutomirski	  If unsure, select "Emulate execution only".
23383dc33bd3SKees Cook
2339bd49e16eSAndy Lutomirski	config LEGACY_VSYSCALL_XONLY
2340bd49e16eSAndy Lutomirski		bool "Emulate execution only"
2341bd49e16eSAndy Lutomirski		help
2342bd49e16eSAndy Lutomirski		  The kernel traps and emulates calls into the fixed vsyscall
2343bd49e16eSAndy Lutomirski		  address mapping and does not allow reads.  This
2344bd49e16eSAndy Lutomirski		  configuration is recommended when userspace might use the
2345bd49e16eSAndy Lutomirski		  legacy vsyscall area but support for legacy binary
2346bd49e16eSAndy Lutomirski		  instrumentation of legacy code is not needed.  It mitigates
2347bd49e16eSAndy Lutomirski		  certain uses of the vsyscall area as an ASLR-bypassing
2348bd49e16eSAndy Lutomirski		  buffer.
23493dc33bd3SKees Cook
23503dc33bd3SKees Cook	config LEGACY_VSYSCALL_NONE
23513dc33bd3SKees Cook		bool "None"
23523dc33bd3SKees Cook		help
23533dc33bd3SKees Cook		  There will be no vsyscall mapping at all. This will
23543dc33bd3SKees Cook		  eliminate any risk of ASLR bypass due to the vsyscall
23553dc33bd3SKees Cook		  fixed address mapping. Attempts to use the vsyscalls
23563dc33bd3SKees Cook		  will be reported to dmesg, so that either old or
23573dc33bd3SKees Cook		  malicious userspace programs can be identified.
23583dc33bd3SKees Cook
23593dc33bd3SKees Cookendchoice
23603dc33bd3SKees Cook
2361516cbf37STim Birdconfig CMDLINE_BOOL
2362516cbf37STim Bird	bool "Built-in kernel command line"
2363a7f7f624SMasahiro Yamada	help
2364516cbf37STim Bird	  Allow for specifying boot arguments to the kernel at
2365516cbf37STim Bird	  build time.  On some systems (e.g. embedded ones), it is
2366516cbf37STim Bird	  necessary or convenient to provide some or all of the
2367516cbf37STim Bird	  kernel boot arguments with the kernel itself (that is,
2368516cbf37STim Bird	  to not rely on the boot loader to provide them.)
2369516cbf37STim Bird
2370516cbf37STim Bird	  To compile command line arguments into the kernel,
2371516cbf37STim Bird	  set this option to 'Y', then fill in the
237269711ca1SSébastien Hinderer	  boot arguments in CONFIG_CMDLINE.
2373516cbf37STim Bird
2374516cbf37STim Bird	  Systems with fully functional boot loaders (i.e. non-embedded)
2375516cbf37STim Bird	  should leave this option set to 'N'.
2376516cbf37STim Bird
2377516cbf37STim Birdconfig CMDLINE
2378516cbf37STim Bird	string "Built-in kernel command string"
2379516cbf37STim Bird	depends on CMDLINE_BOOL
2380516cbf37STim Bird	default ""
2381a7f7f624SMasahiro Yamada	help
2382516cbf37STim Bird	  Enter arguments here that should be compiled into the kernel
2383516cbf37STim Bird	  image and used at boot time.  If the boot loader provides a
2384516cbf37STim Bird	  command line at boot time, it is appended to this string to
2385516cbf37STim Bird	  form the full kernel command line, when the system boots.
2386516cbf37STim Bird
2387516cbf37STim Bird	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2388516cbf37STim Bird	  change this behavior.
2389516cbf37STim Bird
2390516cbf37STim Bird	  In most cases, the command line (whether built-in or provided
2391516cbf37STim Bird	  by the boot loader) should specify the device for the root
2392516cbf37STim Bird	  file system.
2393516cbf37STim Bird
2394516cbf37STim Birdconfig CMDLINE_OVERRIDE
2395516cbf37STim Bird	bool "Built-in command line overrides boot loader arguments"
2396645e6466SAnders Roxell	depends on CMDLINE_BOOL && CMDLINE != ""
2397a7f7f624SMasahiro Yamada	help
2398516cbf37STim Bird	  Set this option to 'Y' to have the kernel ignore the boot loader
2399516cbf37STim Bird	  command line, and use ONLY the built-in command line.
2400516cbf37STim Bird
2401516cbf37STim Bird	  This is used to work around broken boot loaders.  This should
2402516cbf37STim Bird	  be set to 'N' under normal conditions.
2403516cbf37STim Bird
2404a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL
2405a5b9e5a2SAndy Lutomirski	bool "Enable the LDT (local descriptor table)" if EXPERT
2406a5b9e5a2SAndy Lutomirski	default y
2407a7f7f624SMasahiro Yamada	help
2408a5b9e5a2SAndy Lutomirski	  Linux can allow user programs to install a per-process x86
2409a5b9e5a2SAndy Lutomirski	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2410a5b9e5a2SAndy Lutomirski	  call.  This is required to run 16-bit or segmented code such as
2411a5b9e5a2SAndy Lutomirski	  DOSEMU or some Wine programs.  It is also used by some very old
2412a5b9e5a2SAndy Lutomirski	  threading libraries.
2413a5b9e5a2SAndy Lutomirski
2414a5b9e5a2SAndy Lutomirski	  Enabling this feature adds a small amount of overhead to
2415a5b9e5a2SAndy Lutomirski	  context switches and increases the low-level kernel attack
2416a5b9e5a2SAndy Lutomirski	  surface.  Disabling it removes the modify_ldt(2) system call.
2417a5b9e5a2SAndy Lutomirski
2418a5b9e5a2SAndy Lutomirski	  Saying 'N' here may make sense for embedded or server kernels.
2419a5b9e5a2SAndy Lutomirski
24203aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE
24213aac3ebeSThomas Gleixner	bool "Enforce strict size checking for sigaltstack"
24223aac3ebeSThomas Gleixner	depends on DYNAMIC_SIGFRAME
24233aac3ebeSThomas Gleixner	help
24243aac3ebeSThomas Gleixner	  For historical reasons MINSIGSTKSZ is a constant which became
24253aac3ebeSThomas Gleixner	  already too small with AVX512 support. Add a mechanism to
24263aac3ebeSThomas Gleixner	  enforce strict checking of the sigaltstack size against the
24273aac3ebeSThomas Gleixner	  real size of the FPU frame. This option enables the check
24283aac3ebeSThomas Gleixner	  by default. It can also be controlled via the kernel command
24293aac3ebeSThomas Gleixner	  line option 'strict_sas_size' independent of this config
24303aac3ebeSThomas Gleixner	  switch. Enabling it might break existing applications which
24313aac3ebeSThomas Gleixner	  allocate a too small sigaltstack but 'work' because they
24323aac3ebeSThomas Gleixner	  never get a signal delivered.
24333aac3ebeSThomas Gleixner
24343aac3ebeSThomas Gleixner	  Say 'N' unless you want to really enforce this check.
24353aac3ebeSThomas Gleixner
2436b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig"
2437b700e7f0SSeth Jennings
2438506f1d07SSam Ravnborgendmenu
2439506f1d07SSam Ravnborg
24403072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES
24413072e413SMichal Hocko	def_bool y
24425c11f00bSDavid Hildenbrand	depends on ARCH_ENABLE_MEMORY_HOTPLUG
24433072e413SMichal Hocko
2444f91ef222SOscar Salvadorconfig ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2445f91ef222SOscar Salvador	def_bool y
2446f91ef222SOscar Salvador
2447da85f865SBjorn Helgaasmenu "Power management and ACPI options"
2448e279b6c1SSam Ravnborg
2449e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER
24503c2362e6SHarvey Harrison	def_bool y
245144556530SZhimin Gu	depends on HIBERNATION
2452e279b6c1SSam Ravnborg
2453e279b6c1SSam Ravnborgsource "kernel/power/Kconfig"
2454e279b6c1SSam Ravnborg
2455e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig"
2456e279b6c1SSam Ravnborg
2457a6b68076SAndi Kleenconfig X86_APM_BOOT
24586fc108a0SJan Beulich	def_bool y
2459282e5aabSPaul Bolle	depends on APM
2460a6b68076SAndi Kleen
2461e279b6c1SSam Ravnborgmenuconfig APM
2462e279b6c1SSam Ravnborg	tristate "APM (Advanced Power Management) BIOS support"
2463efefa6f6SIngo Molnar	depends on X86_32 && PM_SLEEP
2464a7f7f624SMasahiro Yamada	help
2465e279b6c1SSam Ravnborg	  APM is a BIOS specification for saving power using several different
2466e279b6c1SSam Ravnborg	  techniques. This is mostly useful for battery powered laptops with
2467e279b6c1SSam Ravnborg	  APM compliant BIOSes. If you say Y here, the system time will be
2468e279b6c1SSam Ravnborg	  reset after a RESUME operation, the /proc/apm device will provide
2469e279b6c1SSam Ravnborg	  battery status information, and user-space programs will receive
2470e279b6c1SSam Ravnborg	  notification of APM "events" (e.g. battery status change).
2471e279b6c1SSam Ravnborg
2472e279b6c1SSam Ravnborg	  If you select "Y" here, you can disable actual use of the APM
2473e279b6c1SSam Ravnborg	  BIOS by passing the "apm=off" option to the kernel at boot time.
2474e279b6c1SSam Ravnborg
2475e279b6c1SSam Ravnborg	  Note that the APM support is almost completely disabled for
2476e279b6c1SSam Ravnborg	  machines with more than one CPU.
2477e279b6c1SSam Ravnborg
2478e279b6c1SSam Ravnborg	  In order to use APM, you will need supporting software. For location
2479151f4e2bSMauro Carvalho Chehab	  and more information, read <file:Documentation/power/apm-acpi.rst>
24802dc98fd3SMichael Witten	  and the Battery Powered Linux mini-HOWTO, available from
2481e279b6c1SSam Ravnborg	  <http://www.tldp.org/docs.html#howto>.
2482e279b6c1SSam Ravnborg
2483e279b6c1SSam Ravnborg	  This driver does not spin down disk drives (see the hdparm(8)
2484e279b6c1SSam Ravnborg	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2485e279b6c1SSam Ravnborg	  VESA-compliant "green" monitors.
2486e279b6c1SSam Ravnborg
2487e279b6c1SSam Ravnborg	  This driver does not support the TI 4000M TravelMate and the ACER
2488e279b6c1SSam Ravnborg	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2489e279b6c1SSam Ravnborg	  desktop machines also don't have compliant BIOSes, and this driver
2490e279b6c1SSam Ravnborg	  may cause those machines to panic during the boot phase.
2491e279b6c1SSam Ravnborg
2492e279b6c1SSam Ravnborg	  Generally, if you don't have a battery in your machine, there isn't
2493e279b6c1SSam Ravnborg	  much point in using this driver and you should say N. If you get
2494e279b6c1SSam Ravnborg	  random kernel OOPSes or reboots that don't seem to be related to
2495e279b6c1SSam Ravnborg	  anything, try disabling/enabling this option (or disabling/enabling
2496e279b6c1SSam Ravnborg	  APM in your BIOS).
2497e279b6c1SSam Ravnborg
2498e279b6c1SSam Ravnborg	  Some other things you should try when experiencing seemingly random,
2499e279b6c1SSam Ravnborg	  "weird" problems:
2500e279b6c1SSam Ravnborg
2501e279b6c1SSam Ravnborg	  1) make sure that you have enough swap space and that it is
2502e279b6c1SSam Ravnborg	  enabled.
2503e279b6c1SSam Ravnborg	  2) pass the "no-hlt" option to the kernel
2504e279b6c1SSam Ravnborg	  3) switch on floating point emulation in the kernel and pass
2505e279b6c1SSam Ravnborg	  the "no387" option to the kernel
2506e279b6c1SSam Ravnborg	  4) pass the "floppy=nodma" option to the kernel
2507e279b6c1SSam Ravnborg	  5) pass the "mem=4M" option to the kernel (thereby disabling
2508e279b6c1SSam Ravnborg	  all but the first 4 MB of RAM)
2509e279b6c1SSam Ravnborg	  6) make sure that the CPU is not over clocked.
2510e279b6c1SSam Ravnborg	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2511e279b6c1SSam Ravnborg	  8) disable the cache from your BIOS settings
2512e279b6c1SSam Ravnborg	  9) install a fan for the video card or exchange video RAM
2513e279b6c1SSam Ravnborg	  10) install a better fan for the CPU
2514e279b6c1SSam Ravnborg	  11) exchange RAM chips
2515e279b6c1SSam Ravnborg	  12) exchange the motherboard.
2516e279b6c1SSam Ravnborg
2517e279b6c1SSam Ravnborg	  To compile this driver as a module, choose M here: the
2518e279b6c1SSam Ravnborg	  module will be called apm.
2519e279b6c1SSam Ravnborg
2520e279b6c1SSam Ravnborgif APM
2521e279b6c1SSam Ravnborg
2522e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND
2523e279b6c1SSam Ravnborg	bool "Ignore USER SUSPEND"
2524a7f7f624SMasahiro Yamada	help
2525e279b6c1SSam Ravnborg	  This option will ignore USER SUSPEND requests. On machines with a
2526e279b6c1SSam Ravnborg	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2527e279b6c1SSam Ravnborg	  series notebooks, it is necessary to say Y because of a BIOS bug.
2528e279b6c1SSam Ravnborg
2529e279b6c1SSam Ravnborgconfig APM_DO_ENABLE
2530e279b6c1SSam Ravnborg	bool "Enable PM at boot time"
2531a7f7f624SMasahiro Yamada	help
2532e279b6c1SSam Ravnborg	  Enable APM features at boot time. From page 36 of the APM BIOS
2533e279b6c1SSam Ravnborg	  specification: "When disabled, the APM BIOS does not automatically
2534e279b6c1SSam Ravnborg	  power manage devices, enter the Standby State, enter the Suspend
2535e279b6c1SSam Ravnborg	  State, or take power saving steps in response to CPU Idle calls."
2536e279b6c1SSam Ravnborg	  This driver will make CPU Idle calls when Linux is idle (unless this
2537e279b6c1SSam Ravnborg	  feature is turned off -- see "Do CPU IDLE calls", below). This
2538e279b6c1SSam Ravnborg	  should always save battery power, but more complicated APM features
2539e279b6c1SSam Ravnborg	  will be dependent on your BIOS implementation. You may need to turn
2540e279b6c1SSam Ravnborg	  this option off if your computer hangs at boot time when using APM
2541e279b6c1SSam Ravnborg	  support, or if it beeps continuously instead of suspending. Turn
2542e279b6c1SSam Ravnborg	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2543e279b6c1SSam Ravnborg	  T400CDT. This is off by default since most machines do fine without
2544e279b6c1SSam Ravnborg	  this feature.
2545e279b6c1SSam Ravnborg
2546e279b6c1SSam Ravnborgconfig APM_CPU_IDLE
2547dd8af076SLen Brown	depends on CPU_IDLE
2548e279b6c1SSam Ravnborg	bool "Make CPU Idle calls when idle"
2549a7f7f624SMasahiro Yamada	help
2550e279b6c1SSam Ravnborg	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2551e279b6c1SSam Ravnborg	  On some machines, this can activate improved power savings, such as
2552e279b6c1SSam Ravnborg	  a slowed CPU clock rate, when the machine is idle. These idle calls
2553e279b6c1SSam Ravnborg	  are made after the idle loop has run for some length of time (e.g.,
2554e279b6c1SSam Ravnborg	  333 mS). On some machines, this will cause a hang at boot time or
2555e279b6c1SSam Ravnborg	  whenever the CPU becomes idle. (On machines with more than one CPU,
2556e279b6c1SSam Ravnborg	  this option does nothing.)
2557e279b6c1SSam Ravnborg
2558e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK
2559e279b6c1SSam Ravnborg	bool "Enable console blanking using APM"
2560a7f7f624SMasahiro Yamada	help
2561e279b6c1SSam Ravnborg	  Enable console blanking using the APM. Some laptops can use this to
2562e279b6c1SSam Ravnborg	  turn off the LCD backlight when the screen blanker of the Linux
2563e279b6c1SSam Ravnborg	  virtual console blanks the screen. Note that this is only used by
2564e279b6c1SSam Ravnborg	  the virtual console screen blanker, and won't turn off the backlight
2565e279b6c1SSam Ravnborg	  when using the X Window system. This also doesn't have anything to
2566e279b6c1SSam Ravnborg	  do with your VESA-compliant power-saving monitor. Further, this
2567e279b6c1SSam Ravnborg	  option doesn't work for all laptops -- it might not turn off your
2568e279b6c1SSam Ravnborg	  backlight at all, or it might print a lot of errors to the console,
2569e279b6c1SSam Ravnborg	  especially if you are using gpm.
2570e279b6c1SSam Ravnborg
2571e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS
2572e279b6c1SSam Ravnborg	bool "Allow interrupts during APM BIOS calls"
2573a7f7f624SMasahiro Yamada	help
2574e279b6c1SSam Ravnborg	  Normally we disable external interrupts while we are making calls to
2575e279b6c1SSam Ravnborg	  the APM BIOS as a measure to lessen the effects of a badly behaving
2576e279b6c1SSam Ravnborg	  BIOS implementation.  The BIOS should reenable interrupts if it
2577e279b6c1SSam Ravnborg	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2578e279b6c1SSam Ravnborg	  many of the newer IBM Thinkpads.  If you experience hangs when you
2579e279b6c1SSam Ravnborg	  suspend, try setting this to Y.  Otherwise, say N.
2580e279b6c1SSam Ravnborg
2581e279b6c1SSam Ravnborgendif # APM
2582e279b6c1SSam Ravnborg
2583bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig"
2584e279b6c1SSam Ravnborg
2585e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig"
2586e279b6c1SSam Ravnborg
258727471fdbSAndy Henroidsource "drivers/idle/Kconfig"
258827471fdbSAndy Henroid
2589e279b6c1SSam Ravnborgendmenu
2590e279b6c1SSam Ravnborg
2591e279b6c1SSam Ravnborg
2592e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)"
2593e279b6c1SSam Ravnborg
2594e279b6c1SSam Ravnborgchoice
2595e279b6c1SSam Ravnborg	prompt "PCI access mode"
2596efefa6f6SIngo Molnar	depends on X86_32 && PCI
2597e279b6c1SSam Ravnborg	default PCI_GOANY
2598a7f7f624SMasahiro Yamada	help
2599e279b6c1SSam Ravnborg	  On PCI systems, the BIOS can be used to detect the PCI devices and
2600e279b6c1SSam Ravnborg	  determine their configuration. However, some old PCI motherboards
2601e279b6c1SSam Ravnborg	  have BIOS bugs and may crash if this is done. Also, some embedded
2602e279b6c1SSam Ravnborg	  PCI-based systems don't have any BIOS at all. Linux can also try to
2603e279b6c1SSam Ravnborg	  detect the PCI hardware directly without using the BIOS.
2604e279b6c1SSam Ravnborg
2605e279b6c1SSam Ravnborg	  With this option, you can specify how Linux should detect the
2606e279b6c1SSam Ravnborg	  PCI devices. If you choose "BIOS", the BIOS will be used,
2607e279b6c1SSam Ravnborg	  if you choose "Direct", the BIOS won't be used, and if you
2608e279b6c1SSam Ravnborg	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2609e279b6c1SSam Ravnborg	  If you choose "Any", the kernel will try MMCONFIG, then the
2610e279b6c1SSam Ravnborg	  direct access method and falls back to the BIOS if that doesn't
2611e279b6c1SSam Ravnborg	  work. If unsure, go with the default, which is "Any".
2612e279b6c1SSam Ravnborg
2613e279b6c1SSam Ravnborgconfig PCI_GOBIOS
2614e279b6c1SSam Ravnborg	bool "BIOS"
2615e279b6c1SSam Ravnborg
2616e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG
2617e279b6c1SSam Ravnborg	bool "MMConfig"
2618e279b6c1SSam Ravnborg
2619e279b6c1SSam Ravnborgconfig PCI_GODIRECT
2620e279b6c1SSam Ravnborg	bool "Direct"
2621e279b6c1SSam Ravnborg
26223ef0e1f8SAndres Salomonconfig PCI_GOOLPC
262376fb6570SDaniel Drake	bool "OLPC XO-1"
26243ef0e1f8SAndres Salomon	depends on OLPC
26253ef0e1f8SAndres Salomon
26262bdd1b03SAndres Salomonconfig PCI_GOANY
26272bdd1b03SAndres Salomon	bool "Any"
26282bdd1b03SAndres Salomon
2629e279b6c1SSam Ravnborgendchoice
2630e279b6c1SSam Ravnborg
2631e279b6c1SSam Ravnborgconfig PCI_BIOS
26323c2362e6SHarvey Harrison	def_bool y
2633efefa6f6SIngo Molnar	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2634e279b6c1SSam Ravnborg
2635e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2636e279b6c1SSam Ravnborgconfig PCI_DIRECT
26373c2362e6SHarvey Harrison	def_bool y
26380aba496fSShaohua Li	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2639e279b6c1SSam Ravnborg
2640e279b6c1SSam Ravnborgconfig PCI_MMCONFIG
2641b45c9f36SJan Kiszka	bool "Support mmconfig PCI config space access" if X86_64
2642b45c9f36SJan Kiszka	default y
26434590d98fSAndy Shevchenko	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2644b45c9f36SJan Kiszka	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2645e279b6c1SSam Ravnborg
26463ef0e1f8SAndres Salomonconfig PCI_OLPC
26472bdd1b03SAndres Salomon	def_bool y
26482bdd1b03SAndres Salomon	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
26493ef0e1f8SAndres Salomon
2650b5401a96SAlex Nixonconfig PCI_XEN
2651b5401a96SAlex Nixon	def_bool y
2652b5401a96SAlex Nixon	depends on PCI && XEN
2653b5401a96SAlex Nixon
26548364e1f8SJan Kiszkaconfig MMCONF_FAM10H
26558364e1f8SJan Kiszka	def_bool y
26568364e1f8SJan Kiszka	depends on X86_64 && PCI_MMCONFIG && ACPI
2657e279b6c1SSam Ravnborg
26583f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK
26596a108a14SDavid Rientjes	bool "Read CNB20LE Host Bridge Windows" if EXPERT
26606ea30386SKees Cook	depends on PCI
26613f6ea84aSIra W. Snyder	help
26623f6ea84aSIra W. Snyder	  Read the PCI windows out of the CNB20LE host bridge. This allows
26633f6ea84aSIra W. Snyder	  PCI hotplug to work on systems with the CNB20LE chipset which do
26643f6ea84aSIra W. Snyder	  not have ACPI.
26653f6ea84aSIra W. Snyder
266664a5fed6SBjorn Helgaas	  There's no public spec for this chipset, and this functionality
266764a5fed6SBjorn Helgaas	  is known to be incomplete.
266864a5fed6SBjorn Helgaas
266964a5fed6SBjorn Helgaas	  You should say N unless you know you need this.
267064a5fed6SBjorn Helgaas
26713a495511SWilliam Breathitt Grayconfig ISA_BUS
267217a2a129SWilliam Breathitt Gray	bool "ISA bus support on modern systems" if EXPERT
26733a495511SWilliam Breathitt Gray	help
267417a2a129SWilliam Breathitt Gray	  Expose ISA bus device drivers and options available for selection and
267517a2a129SWilliam Breathitt Gray	  configuration. Enable this option if your target machine has an ISA
267617a2a129SWilliam Breathitt Gray	  bus. ISA is an older system, displaced by PCI and newer bus
267717a2a129SWilliam Breathitt Gray	  architectures -- if your target machine is modern, it probably does
267817a2a129SWilliam Breathitt Gray	  not have an ISA bus.
26793a495511SWilliam Breathitt Gray
26803a495511SWilliam Breathitt Gray	  If unsure, say N.
26813a495511SWilliam Breathitt Gray
26821c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA.
2683e279b6c1SSam Ravnborgconfig ISA_DMA_API
26841c00f016SDavid Rientjes	bool "ISA-style DMA support" if (X86_64 && EXPERT)
26851c00f016SDavid Rientjes	default y
26861c00f016SDavid Rientjes	help
26871c00f016SDavid Rientjes	  Enables ISA-style DMA support for devices requiring such controllers.
26881c00f016SDavid Rientjes	  If unsure, say Y.
2689e279b6c1SSam Ravnborg
269051e68d05SLinus Torvaldsif X86_32
269151e68d05SLinus Torvalds
2692e279b6c1SSam Ravnborgconfig ISA
2693e279b6c1SSam Ravnborg	bool "ISA support"
2694a7f7f624SMasahiro Yamada	help
2695e279b6c1SSam Ravnborg	  Find out whether you have ISA slots on your motherboard.  ISA is the
2696e279b6c1SSam Ravnborg	  name of a bus system, i.e. the way the CPU talks to the other stuff
2697e279b6c1SSam Ravnborg	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2698e279b6c1SSam Ravnborg	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2699e279b6c1SSam Ravnborg	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2700e279b6c1SSam Ravnborg
2701e279b6c1SSam Ravnborgconfig SCx200
2702e279b6c1SSam Ravnborg	tristate "NatSemi SCx200 support"
2703a7f7f624SMasahiro Yamada	help
2704e279b6c1SSam Ravnborg	  This provides basic support for National Semiconductor's
2705e279b6c1SSam Ravnborg	  (now AMD's) Geode processors.  The driver probes for the
2706e279b6c1SSam Ravnborg	  PCI-IDs of several on-chip devices, so its a good dependency
2707e279b6c1SSam Ravnborg	  for other scx200_* drivers.
2708e279b6c1SSam Ravnborg
2709e279b6c1SSam Ravnborg	  If compiled as a module, the driver is named scx200.
2710e279b6c1SSam Ravnborg
2711e279b6c1SSam Ravnborgconfig SCx200HR_TIMER
2712e279b6c1SSam Ravnborg	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2713592913ecSJohn Stultz	depends on SCx200
2714e279b6c1SSam Ravnborg	default y
2715a7f7f624SMasahiro Yamada	help
2716e279b6c1SSam Ravnborg	  This driver provides a clocksource built upon the on-chip
2717e279b6c1SSam Ravnborg	  27MHz high-resolution timer.  Its also a workaround for
2718e279b6c1SSam Ravnborg	  NSC Geode SC-1100's buggy TSC, which loses time when the
2719e279b6c1SSam Ravnborg	  processor goes idle (as is done by the scheduler).  The
2720e279b6c1SSam Ravnborg	  other workaround is idle=poll boot option.
2721e279b6c1SSam Ravnborg
27223ef0e1f8SAndres Salomonconfig OLPC
27233ef0e1f8SAndres Salomon	bool "One Laptop Per Child support"
272454008979SThomas Gleixner	depends on !X86_PAE
27253c554946SAndres Salomon	select GPIOLIB
2726dc3119e7SThomas Gleixner	select OF
272745bb1674SDaniel Drake	select OF_PROMTREE
2728b4e51854SGrant Likely	select IRQ_DOMAIN
27290c3d931bSLubomir Rintel	select OLPC_EC
2730a7f7f624SMasahiro Yamada	help
27313ef0e1f8SAndres Salomon	  Add support for detecting the unique features of the OLPC
27323ef0e1f8SAndres Salomon	  XO hardware.
27333ef0e1f8SAndres Salomon
2734a3128588SDaniel Drakeconfig OLPC_XO1_PM
2735a3128588SDaniel Drake	bool "OLPC XO-1 Power Management"
2736fa112cf1SBorislav Petkov	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2737a7f7f624SMasahiro Yamada	help
273897c4cb71SDaniel Drake	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2739bf1ebf00SDaniel Drake
2740cfee9597SDaniel Drakeconfig OLPC_XO1_RTC
2741cfee9597SDaniel Drake	bool "OLPC XO-1 Real Time Clock"
2742cfee9597SDaniel Drake	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2743a7f7f624SMasahiro Yamada	help
2744cfee9597SDaniel Drake	  Add support for the XO-1 real time clock, which can be used as a
2745cfee9597SDaniel Drake	  programmable wakeup source.
2746cfee9597SDaniel Drake
27477feda8e9SDaniel Drakeconfig OLPC_XO1_SCI
27487feda8e9SDaniel Drake	bool "OLPC XO-1 SCI extras"
274992e830f2SArnd Bergmann	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2750ed8e47feSRandy Dunlap	depends on INPUT=y
2751d8d01a63SDaniel Drake	select POWER_SUPPLY
2752a7f7f624SMasahiro Yamada	help
27537feda8e9SDaniel Drake	  Add support for SCI-based features of the OLPC XO-1 laptop:
27547bc74b3dSDaniel Drake	   - EC-driven system wakeups
27557feda8e9SDaniel Drake	   - Power button
27567bc74b3dSDaniel Drake	   - Ebook switch
27572cf2baeaSDaniel Drake	   - Lid switch
2758e1040ac6SDaniel Drake	   - AC adapter status updates
2759e1040ac6SDaniel Drake	   - Battery status updates
27607feda8e9SDaniel Drake
2761a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI
2762a0f30f59SDaniel Drake	bool "OLPC XO-1.5 SCI extras"
2763d8d01a63SDaniel Drake	depends on OLPC && ACPI
2764d8d01a63SDaniel Drake	select POWER_SUPPLY
2765a7f7f624SMasahiro Yamada	help
2766a0f30f59SDaniel Drake	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2767a0f30f59SDaniel Drake	   - EC-driven system wakeups
2768a0f30f59SDaniel Drake	   - AC adapter status updates
2769a0f30f59SDaniel Drake	   - Battery status updates
2770e279b6c1SSam Ravnborg
2771d4f3e350SEd Wildgooseconfig ALIX
2772d4f3e350SEd Wildgoose	bool "PCEngines ALIX System Support (LED setup)"
2773d4f3e350SEd Wildgoose	select GPIOLIB
2774a7f7f624SMasahiro Yamada	help
2775d4f3e350SEd Wildgoose	  This option enables system support for the PCEngines ALIX.
2776d4f3e350SEd Wildgoose	  At present this just sets up LEDs for GPIO control on
2777d4f3e350SEd Wildgoose	  ALIX2/3/6 boards.  However, other system specific setup should
2778d4f3e350SEd Wildgoose	  get added here.
2779d4f3e350SEd Wildgoose
2780d4f3e350SEd Wildgoose	  Note: You must still enable the drivers for GPIO and LED support
2781d4f3e350SEd Wildgoose	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2782d4f3e350SEd Wildgoose
2783d4f3e350SEd Wildgoose	  Note: You have to set alix.force=1 for boards with Award BIOS.
2784d4f3e350SEd Wildgoose
2785da4e3302SPhilip Prindevilleconfig NET5501
2786da4e3302SPhilip Prindeville	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2787da4e3302SPhilip Prindeville	select GPIOLIB
2788a7f7f624SMasahiro Yamada	help
2789da4e3302SPhilip Prindeville	  This option enables system support for the Soekris Engineering net5501.
2790da4e3302SPhilip Prindeville
27913197059aSPhilip A. Prindevilleconfig GEOS
27923197059aSPhilip A. Prindeville	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
27933197059aSPhilip A. Prindeville	select GPIOLIB
27943197059aSPhilip A. Prindeville	depends on DMI
2795a7f7f624SMasahiro Yamada	help
27963197059aSPhilip A. Prindeville	  This option enables system support for the Traverse Technologies GEOS.
27973197059aSPhilip A. Prindeville
27987d029125SVivien Didelotconfig TS5500
27997d029125SVivien Didelot	bool "Technologic Systems TS-5500 platform support"
28007d029125SVivien Didelot	depends on MELAN
28017d029125SVivien Didelot	select CHECK_SIGNATURE
28027d029125SVivien Didelot	select NEW_LEDS
28037d029125SVivien Didelot	select LEDS_CLASS
2804a7f7f624SMasahiro Yamada	help
28057d029125SVivien Didelot	  This option enables system support for the Technologic Systems TS-5500.
28067d029125SVivien Didelot
2807e279b6c1SSam Ravnborgendif # X86_32
2808e279b6c1SSam Ravnborg
280923ac4ae8SAndreas Herrmannconfig AMD_NB
2810e279b6c1SSam Ravnborg	def_bool y
28110e152cd7SBorislav Petkov	depends on CPU_SUP_AMD && PCI
2812e279b6c1SSam Ravnborg
2813e279b6c1SSam Ravnborgendmenu
2814e279b6c1SSam Ravnborg
2815e279b6c1SSam Ravnborg
28161572497cSChristoph Hellwigmenu "Binary Emulations"
2817e279b6c1SSam Ravnborg
2818e279b6c1SSam Ravnborgconfig IA32_EMULATION
2819e279b6c1SSam Ravnborg	bool "IA32 Emulation"
2820e279b6c1SSam Ravnborg	depends on X86_64
282139f88911SIngo Molnar	select ARCH_WANT_OLD_COMPAT_IPC
2822d1603990SRandy Dunlap	select BINFMT_ELF
282339f88911SIngo Molnar	select COMPAT_OLD_SIGACTION
2824a7f7f624SMasahiro Yamada	help
28255fd92e65SH. J. Lu	  Include code to run legacy 32-bit programs under a
28265fd92e65SH. J. Lu	  64-bit kernel. You should likely turn this on, unless you're
28275fd92e65SH. J. Lu	  100% sure that you don't have any 32-bit programs left.
2828e279b6c1SSam Ravnborg
2829e279b6c1SSam Ravnborgconfig IA32_AOUT
2830e279b6c1SSam Ravnborg	tristate "IA32 a.out support"
28316b213e1bSDavid Woodhouse	depends on IA32_EMULATION
2832eac61655SBorislav Petkov	depends on BROKEN
2833a7f7f624SMasahiro Yamada	help
2834e279b6c1SSam Ravnborg	  Support old a.out binaries in the 32bit emulation.
2835e279b6c1SSam Ravnborg
283683a44a4fSMasahiro Yamadaconfig X86_X32_ABI
28376ea30386SKees Cook	bool "x32 ABI for 64-bit mode"
28389b54050bSBrian Gerst	depends on X86_64
2839aaeed6ecSNathan Chancellor	# llvm-objcopy does not convert x86_64 .note.gnu.property or
2840aaeed6ecSNathan Chancellor	# compressed debug sections to x86_x32 properly:
2841aaeed6ecSNathan Chancellor	# https://github.com/ClangBuiltLinux/linux/issues/514
2842aaeed6ecSNathan Chancellor	# https://github.com/ClangBuiltLinux/linux/issues/1141
2843aaeed6ecSNathan Chancellor	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
2844a7f7f624SMasahiro Yamada	help
28455fd92e65SH. J. Lu	  Include code to run binaries for the x32 native 32-bit ABI
28465fd92e65SH. J. Lu	  for 64-bit processors.  An x32 process gets access to the
28475fd92e65SH. J. Lu	  full 64-bit register file and wide data path while leaving
28485fd92e65SH. J. Lu	  pointers at 32 bits for smaller memory footprint.
28495fd92e65SH. J. Lu
2850953fee1dSIngo Molnarconfig COMPAT_32
2851953fee1dSIngo Molnar	def_bool y
2852953fee1dSIngo Molnar	depends on IA32_EMULATION || X86_32
2853953fee1dSIngo Molnar	select HAVE_UID16
2854953fee1dSIngo Molnar	select OLD_SIGSUSPEND3
2855953fee1dSIngo Molnar
2856e279b6c1SSam Ravnborgconfig COMPAT
28573c2362e6SHarvey Harrison	def_bool y
285883a44a4fSMasahiro Yamada	depends on IA32_EMULATION || X86_X32_ABI
2859e279b6c1SSam Ravnborg
28603120e25eSJan Beulichif COMPAT
2861e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT
28623120e25eSJan Beulich	def_bool y
2863e279b6c1SSam Ravnborg
2864e279b6c1SSam Ravnborgconfig SYSVIPC_COMPAT
28653c2362e6SHarvey Harrison	def_bool y
28663120e25eSJan Beulich	depends on SYSVIPC
28673120e25eSJan Beulichendif
2868ee009e4aSDavid Howells
2869e279b6c1SSam Ravnborgendmenu
2870e279b6c1SSam Ravnborg
2871e279b6c1SSam Ravnborg
2872e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP
2873e5beae16SKeith Packard	def_bool y
2874e5beae16SKeith Packard	depends on X86_32
2875e5beae16SKeith Packard
2876edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig"
28775e8ebd84SJason A. Donenfeld
28785e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler"
2879