xref: /linux/arch/x86/Kconfig (revision d911c67e10b47eb1ace08dcf95ce98fe4d408c88)
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
796974f0c4SDaniel Micay	select ARCH_HAS_FORTIFY_SOURCE
80957e3facSRiku Voipio	select ARCH_HAS_GCOV_PROFILE_ALL
81bece04b5SMarco Elver	select ARCH_HAS_KCOV			if X86_64
820c9c1d56SThiago Jung Bauermann	select ARCH_HAS_MEM_ENCRYPT
8310bcc80eSMathieu Desnoyers	select ARCH_HAS_MEMBARRIER_SYNC_CORE
840ebeea8cSDaniel Borkmann	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
85c763ea26SIngo Molnar	select ARCH_HAS_PMEM_API		if X86_64
8617596731SRobin Murphy	select ARCH_HAS_PTE_DEVMAP		if X86_64
873010a5eaSLaurent Dufour	select ARCH_HAS_PTE_SPECIAL
88eed9a328SYu Zhao	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
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
12447010c04SMuchun Song	select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP	if X86_64
12559612b24SNathan Chancellor	select ARCH_WANT_LD_ORPHAN_WARN
12638d8b4e6SHuang Ying	select ARCH_WANTS_THP_SWAP		if X86_64
127b5f06f64SBalbir Singh	select ARCH_HAS_PARANOID_L1D_FLUSH
12810916706SShile Zhang	select BUILDTIME_TABLE_SORT
1296471b825SIngo Molnar	select CLKEVT_I8253
1306471b825SIngo Molnar	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
1316471b825SIngo Molnar	select CLOCKSOURCE_WATCHDOG
1326471b825SIngo Molnar	select DCACHE_WORD_ACCESS
1333aac3ebeSThomas Gleixner	select DYNAMIC_SIGFRAME
13445471cd9SLinus Torvalds	select EDAC_ATOMIC_SCRUB
13545471cd9SLinus Torvalds	select EDAC_SUPPORT
1366471b825SIngo Molnar	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
1376471b825SIngo Molnar	select GENERIC_CLOCKEVENTS_MIN_ADJUST
1386471b825SIngo Molnar	select GENERIC_CMOS_UPDATE
1396471b825SIngo Molnar	select GENERIC_CPU_AUTOPROBE
14061dc0f55SThomas Gleixner	select GENERIC_CPU_VULNERABILITIES
1416471b825SIngo Molnar	select GENERIC_EARLY_IOREMAP
14227d6b4d1SThomas Gleixner	select GENERIC_ENTRY
1436471b825SIngo Molnar	select GENERIC_IOMAP
144c7d6c9ddSThomas Gleixner	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
1450fa115daSThomas Gleixner	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
146ad7a929fSThomas Gleixner	select GENERIC_IRQ_MIGRATION		if SMP
1476471b825SIngo Molnar	select GENERIC_IRQ_PROBE
148c201c917SThomas Gleixner	select GENERIC_IRQ_RESERVATION_MODE
1496471b825SIngo Molnar	select GENERIC_IRQ_SHOW
1506471b825SIngo Molnar	select GENERIC_PENDING_IRQ		if SMP
1512ae27137SSteven Price	select GENERIC_PTDUMP
1526471b825SIngo Molnar	select GENERIC_SMP_IDLE_THREAD
1536471b825SIngo Molnar	select GENERIC_TIME_VSYSCALL
1547ac87074SVincenzo Frascino	select GENERIC_GETTIMEOFDAY
155550a77a7SDmitry Safonov	select GENERIC_VDSO_TIME_NS
15639656e83SChristoph Hellwig	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
15717e5888eSHans de Goede	select HARDIRQS_SW_RESEND
1587edaeb68SThomas Gleixner	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
1596471b825SIngo Molnar	select HAVE_ACPI_APEI			if ACPI
1606471b825SIngo Molnar	select HAVE_ACPI_APEI_NMI		if ACPI
1616471b825SIngo Molnar	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
1626471b825SIngo Molnar	select HAVE_ARCH_AUDITSYSCALL
1636471b825SIngo Molnar	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
164eed1fceeSSong Liu	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
1656471b825SIngo Molnar	select HAVE_ARCH_JUMP_LABEL
166b34006c4SArd Biesheuvel	select HAVE_ARCH_JUMP_LABEL_RELATIVE
167d17a1d97SAndrey Ryabinin	select HAVE_ARCH_KASAN			if X86_64
1680609ae01SDaniel Axtens	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
1691dc0da6eSAlexander Potapenko	select HAVE_ARCH_KFENCE
1706471b825SIngo Molnar	select HAVE_ARCH_KGDB
1719e08f57dSDaniel Cashman	select HAVE_ARCH_MMAP_RND_BITS		if MMU
1729e08f57dSDaniel Cashman	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
1731b028f78SDmitry Safonov	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
174271ca788SArd Biesheuvel	select HAVE_ARCH_PREL32_RELOCATIONS
1756471b825SIngo Molnar	select HAVE_ARCH_SECCOMP_FILTER
176f7d83c1cSKees Cook	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
177afaef01cSAlexander Popov	select HAVE_ARCH_STACKLEAK
1786471b825SIngo Molnar	select HAVE_ARCH_TRACEHOOK
1796471b825SIngo Molnar	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
180a00cc7d9SMatthew Wilcox	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
181b64d8d1eSPeter Xu	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
1827677f7fdSAxel Rasmussen	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
183e37e43a4SAndy Lutomirski	select HAVE_ARCH_VMAP_STACK		if X86_64
184fe950f60SKees Cook	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
185c763ea26SIngo Molnar	select HAVE_ARCH_WITHIN_STACK_FRAMES
1862ff2b7ecSMasahiro Yamada	select HAVE_ASM_MODVERSIONS
1876471b825SIngo Molnar	select HAVE_CMPXCHG_DOUBLE
1886471b825SIngo Molnar	select HAVE_CMPXCHG_LOCAL
18924a9c541SFrederic Weisbecker	select HAVE_CONTEXT_TRACKING_USER		if X86_64
19024a9c541SFrederic Weisbecker	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
1916471b825SIngo Molnar	select HAVE_C_RECORDMCOUNT
19203f16cd0SJosh Poimboeuf	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
1934ed308c4SSteven Rostedt (Google)	select HAVE_BUILDTIME_MCOUNT_SORT
1946471b825SIngo Molnar	select HAVE_DEBUG_KMEMLEAK
1959c5a3621SAkinobu Mita	select HAVE_DMA_CONTIGUOUS
196677aa9f7SSteven Rostedt	select HAVE_DYNAMIC_FTRACE
19706aeaaeaSMasami Hiramatsu	select HAVE_DYNAMIC_FTRACE_WITH_REGS
19802a474caSSteven Rostedt (VMware)	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
199562955feSSteven Rostedt (VMware)	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
200c316eb44SHeiko Carstens	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
201503e4510SHeiko Carstens	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
20203f5781bSWang YanQing	select HAVE_EBPF_JIT
20358340a07SJohannes Berg	select HAVE_EFFICIENT_UNALIGNED_ACCESS
2046630a8e5SChristoph Hellwig	select HAVE_EISA
2055f56a5dfSJiri Slaby	select HAVE_EXIT_THREAD
20667a929e0SChristoph Hellwig	select HAVE_FAST_GUP
207644e0e8dSSteven Rostedt (VMware)	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
2086471b825SIngo Molnar	select HAVE_FTRACE_MCOUNT_RECORD
2094a30e4c9SSteven Rostedt (VMware)	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
2106471b825SIngo Molnar	select HAVE_FUNCTION_TRACER
2116b90bd4bSEmese Revfy	select HAVE_GCC_PLUGINS
2120067f129SK.Prasad	select HAVE_HW_BREAKPOINT
2136471b825SIngo Molnar	select HAVE_IOREMAP_PROT
214624db9eaSThomas Gleixner	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
2156471b825SIngo Molnar	select HAVE_IRQ_TIME_ACCOUNTING
2164ab7674fSJosh Poimboeuf	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
2176471b825SIngo Molnar	select HAVE_KERNEL_BZIP2
2186471b825SIngo Molnar	select HAVE_KERNEL_GZIP
2196471b825SIngo Molnar	select HAVE_KERNEL_LZ4
2206471b825SIngo Molnar	select HAVE_KERNEL_LZMA
2216471b825SIngo Molnar	select HAVE_KERNEL_LZO
2226471b825SIngo Molnar	select HAVE_KERNEL_XZ
223fb46d057SNick Terrell	select HAVE_KERNEL_ZSTD
2246471b825SIngo Molnar	select HAVE_KPROBES
2256471b825SIngo Molnar	select HAVE_KPROBES_ON_FTRACE
226540adea3SMasami Hiramatsu	select HAVE_FUNCTION_ERROR_INJECTION
2276471b825SIngo Molnar	select HAVE_KRETPROBES
228f3a112c0SMasami Hiramatsu	select HAVE_RETHOOK
2296471b825SIngo Molnar	select HAVE_KVM
2306471b825SIngo Molnar	select HAVE_LIVEPATCH			if X86_64
2310102752eSFrederic Weisbecker	select HAVE_MIXED_BREAKPOINTS_REGS
232ee9f8fceSJosh Poimboeuf	select HAVE_MOD_ARCH_SPECIFIC
2339f132f7eSJoel Fernandes (Google)	select HAVE_MOVE_PMD
234be37c98dSKalesh Singh	select HAVE_MOVE_PUD
23522102f45SJosh Poimboeuf	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
23642a0bb3fSPetr Mladek	select HAVE_NMI
237489e355bSJosh Poimboeuf	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
23803f16cd0SJosh Poimboeuf	select HAVE_OBJTOOL			if X86_64
2396471b825SIngo Molnar	select HAVE_OPTPROBES
2406471b825SIngo Molnar	select HAVE_PCSPKR_PLATFORM
2416471b825SIngo Molnar	select HAVE_PERF_EVENTS
242c01d4323SFrederic Weisbecker	select HAVE_PERF_EVENTS_NMI
24392e5aae4SNicholas Piggin	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
244eb01d42aSChristoph Hellwig	select HAVE_PCI
245c5e63197SJiri Olsa	select HAVE_PERF_REGS
246c5ebcedbSJiri Olsa	select HAVE_PERF_USER_STACK_DUMP
247ff2e6d72SPeter Zijlstra	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
2481e9fdf21SPeter Zijlstra	select MMU_GATHER_MERGE_VMAS
24900998085SThomas Gleixner	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
2506471b825SIngo Molnar	select HAVE_REGS_AND_STACK_ACCESS_API
25103f16cd0SJosh Poimboeuf	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
2523c88ee19SMasami Hiramatsu	select HAVE_FUNCTION_ARG_ACCESS_API
2537ecd19cfSKefeng Wang	select HAVE_SETUP_PER_CPU_AREA
254cd1a41ceSThomas Gleixner	select HAVE_SOFTIRQ_ON_OWN_STACK
255d148eac0SMasahiro Yamada	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
25603f16cd0SJosh Poimboeuf	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
257e6d6c071SJosh Poimboeuf	select HAVE_STATIC_CALL
25803f16cd0SJosh Poimboeuf	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
25999cf983cSMark Rutland	select HAVE_PREEMPT_DYNAMIC_CALL
260d6761b8fSMathieu Desnoyers	select HAVE_RSEQ
2616471b825SIngo Molnar	select HAVE_SYSCALL_TRACEPOINTS
2625f3da8c0SJosh Poimboeuf	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
2636471b825SIngo Molnar	select HAVE_UNSTABLE_SCHED_CLOCK
2647c68af6eSAvi Kivity	select HAVE_USER_RETURN_NOTIFIER
2657ac87074SVincenzo Frascino	select HAVE_GENERIC_VDSO
26605736e4aSThomas Gleixner	select HOTPLUG_SMT			if SMP
267c0185808SThomas Gleixner	select IRQ_FORCED_THREADING
2687ecd19cfSKefeng Wang	select NEED_PER_CPU_EMBED_FIRST_CHUNK
2697ecd19cfSKefeng Wang	select NEED_PER_CPU_PAGE_FIRST_CHUNK
27086596f0aSChristoph Hellwig	select NEED_SG_DMA_LENGTH
2712eac9c2dSChristoph Hellwig	select PCI_DOMAINS			if PCI
272625210cfSSinan Kaya	select PCI_LOCKLESS_CONFIG		if PCI
2736471b825SIngo Molnar	select PERF_EVENTS
2743195ef59SPrarit Bhargava	select RTC_LIB
275d6faca40SArnd Bergmann	select RTC_MC146818_LIB
2766471b825SIngo Molnar	select SPARSE_IRQ
27783fe27eaSPranith Kumar	select SRCU
2786471b825SIngo Molnar	select SYSCTL_EXCEPTION_TRACE
27915f4eae7SAndy Lutomirski	select THREAD_INFO_IN_TASK
2804aae683fSMasahiro Yamada	select TRACE_IRQFLAGS_SUPPORT
2814510bffbSMark Rutland	select TRACE_IRQFLAGS_NMI_SUPPORT
2826471b825SIngo Molnar	select USER_STACKTRACE_SUPPORT
2833b02a051SIngo Molnar	select HAVE_ARCH_KCSAN			if X86_64
2846471b825SIngo Molnar	select X86_FEATURE_NAMES		if PROC_FS
2850c608dadSAubrey Li	select PROC_PID_ARCH_STATUS		if PROC_FS
28650468e43SJarkko Sakkinen	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
2879e2b4be3SNayna Jain	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
2887d8330a5SBalbir Singh
289ba7e4d13SIngo Molnarconfig INSTRUCTION_DECODER
2903120e25eSJan Beulich	def_bool y
2913120e25eSJan Beulich	depends on KPROBES || PERF_EVENTS || UPROBES
292ba7e4d13SIngo Molnar
29351b26adaSLinus Torvaldsconfig OUTPUT_FORMAT
29451b26adaSLinus Torvalds	string
29551b26adaSLinus Torvalds	default "elf32-i386" if X86_32
29651b26adaSLinus Torvalds	default "elf64-x86-64" if X86_64
29751b26adaSLinus Torvalds
2988d5fffb9SSam Ravnborgconfig LOCKDEP_SUPPORT
2993c2362e6SHarvey Harrison	def_bool y
3008d5fffb9SSam Ravnborg
3018d5fffb9SSam Ravnborgconfig STACKTRACE_SUPPORT
3023c2362e6SHarvey Harrison	def_bool y
3038d5fffb9SSam Ravnborg
3048d5fffb9SSam Ravnborgconfig MMU
3053c2362e6SHarvey Harrison	def_bool y
3068d5fffb9SSam Ravnborg
3079e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MIN
3089e08f57dSDaniel Cashman	default 28 if 64BIT
3099e08f57dSDaniel Cashman	default 8
3109e08f57dSDaniel Cashman
3119e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_BITS_MAX
3129e08f57dSDaniel Cashman	default 32 if 64BIT
3139e08f57dSDaniel Cashman	default 16
3149e08f57dSDaniel Cashman
3159e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MIN
3169e08f57dSDaniel Cashman	default 8
3179e08f57dSDaniel Cashman
3189e08f57dSDaniel Cashmanconfig ARCH_MMAP_RND_COMPAT_BITS_MAX
3199e08f57dSDaniel Cashman	default 16
3209e08f57dSDaniel Cashman
3218d5fffb9SSam Ravnborgconfig SBUS
3228d5fffb9SSam Ravnborg	bool
3238d5fffb9SSam Ravnborg
3248d5fffb9SSam Ravnborgconfig GENERIC_ISA_DMA
3253120e25eSJan Beulich	def_bool y
3263120e25eSJan Beulich	depends on ISA_DMA_API
3278d5fffb9SSam Ravnborg
328*d911c67eSAlexander Potapenkoconfig GENERIC_CSUM
329*d911c67eSAlexander Potapenko	bool
330*d911c67eSAlexander Potapenko	default y if KMSAN || KASAN
331*d911c67eSAlexander Potapenko
3328d5fffb9SSam Ravnborgconfig GENERIC_BUG
3333c2362e6SHarvey Harrison	def_bool y
3348d5fffb9SSam Ravnborg	depends on BUG
335b93a531eSJan Beulich	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
336b93a531eSJan Beulich
337b93a531eSJan Beulichconfig GENERIC_BUG_RELATIVE_POINTERS
338b93a531eSJan Beulich	bool
3398d5fffb9SSam Ravnborg
3408d5fffb9SSam Ravnborgconfig ARCH_MAY_HAVE_PC_FDC
3413120e25eSJan Beulich	def_bool y
3423120e25eSJan Beulich	depends on ISA_DMA_API
3438d5fffb9SSam Ravnborg
3441032c0baSSam Ravnborgconfig GENERIC_CALIBRATE_DELAY
3451032c0baSSam Ravnborg	def_bool y
3461032c0baSSam Ravnborg
3479a0b8415Svenkatesh.pallipadi@intel.comconfig ARCH_HAS_CPU_RELAX
3489a0b8415Svenkatesh.pallipadi@intel.com	def_bool y
3498d5fffb9SSam Ravnborg
350801e4062SJohannes Bergconfig ARCH_HIBERNATION_POSSIBLE
351801e4062SJohannes Berg	def_bool y
352801e4062SJohannes Berg
353d7109fe3SAndy Shevchenkoconfig ARCH_NR_GPIO
354d7109fe3SAndy Shevchenko	int
355d7109fe3SAndy Shevchenko	default 1024 if X86_64
356d7109fe3SAndy Shevchenko	default 512
357d7109fe3SAndy Shevchenko
358f4cb5700SJohannes Bergconfig ARCH_SUSPEND_POSSIBLE
359f4cb5700SJohannes Berg	def_bool y
360f4cb5700SJohannes Berg
3618d5fffb9SSam Ravnborgconfig AUDIT_ARCH
362e0fd24a3SJan Beulich	def_bool y if X86_64
3638d5fffb9SSam Ravnborg
364d6f2d75aSAndrey Ryabininconfig KASAN_SHADOW_OFFSET
365d6f2d75aSAndrey Ryabinin	hex
366d6f2d75aSAndrey Ryabinin	depends on KASAN
367d6f2d75aSAndrey Ryabinin	default 0xdffffc0000000000
368d6f2d75aSAndrey Ryabinin
36969575d38SShane Wangconfig HAVE_INTEL_TXT
37069575d38SShane Wang	def_bool y
3716ea30386SKees Cook	depends on INTEL_IOMMU && ACPI
37269575d38SShane Wang
3736b0c3d44SSam Ravnborgconfig X86_32_SMP
3746b0c3d44SSam Ravnborg	def_bool y
3756b0c3d44SSam Ravnborg	depends on X86_32 && SMP
3766b0c3d44SSam Ravnborg
3776b0c3d44SSam Ravnborgconfig X86_64_SMP
3786b0c3d44SSam Ravnborg	def_bool y
3796b0c3d44SSam Ravnborg	depends on X86_64 && SMP
3806b0c3d44SSam Ravnborg
3812b144498SSrikar Dronamrajuconfig ARCH_SUPPORTS_UPROBES
3822b144498SSrikar Dronamraju	def_bool y
3832b144498SSrikar Dronamraju
384d20642f0SRob Herringconfig FIX_EARLYCON_MEM
385d20642f0SRob Herring	def_bool y
386d20642f0SRob Herring
38794d49eb3SKirill A. Shutemovconfig DYNAMIC_PHYSICAL_MASK
38894d49eb3SKirill A. Shutemov	bool
38994d49eb3SKirill A. Shutemov
39098233368SKirill A. Shutemovconfig PGTABLE_LEVELS
39198233368SKirill A. Shutemov	int
39277ef56e4SKirill A. Shutemov	default 5 if X86_5LEVEL
39398233368SKirill A. Shutemov	default 4 if X86_64
39498233368SKirill A. Shutemov	default 3 if X86_PAE
39598233368SKirill A. Shutemov	default 2
39698233368SKirill A. Shutemov
3972a61f474SMasahiro Yamadaconfig CC_HAS_SANE_STACKPROTECTOR
3982a61f474SMasahiro Yamada	bool
3991b866781SNathan Chancellor	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
4001b866781SNathan Chancellor	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
4012a61f474SMasahiro Yamada	help
4022a61f474SMasahiro Yamada	  We have to make sure stack protector is unconditionally disabled if
4033fb0fdb3SAndy Lutomirski	  the compiler produces broken code or if it does not let us control
4043fb0fdb3SAndy Lutomirski	  the segment on 32-bit kernels.
4052a61f474SMasahiro Yamada
406506f1d07SSam Ravnborgmenu "Processor type and features"
407506f1d07SSam Ravnborg
408506f1d07SSam Ravnborgconfig SMP
409506f1d07SSam Ravnborg	bool "Symmetric multi-processing support"
410a7f7f624SMasahiro Yamada	help
411506f1d07SSam Ravnborg	  This enables support for systems with more than one CPU. If you have
4124a474157SRobert Graffham	  a system with only one CPU, say N. If you have a system with more
4134a474157SRobert Graffham	  than one CPU, say Y.
414506f1d07SSam Ravnborg
4154a474157SRobert Graffham	  If you say N here, the kernel will run on uni- and multiprocessor
416506f1d07SSam Ravnborg	  machines, but will use only one CPU of a multiprocessor machine. If
417506f1d07SSam Ravnborg	  you say Y here, the kernel will run on many, but not all,
4184a474157SRobert Graffham	  uniprocessor machines. On a uniprocessor machine, the kernel
419506f1d07SSam Ravnborg	  will run faster if you say N here.
420506f1d07SSam Ravnborg
421506f1d07SSam Ravnborg	  Note that if you say Y here and choose architecture "586" or
422506f1d07SSam Ravnborg	  "Pentium" under "Processor family", the kernel will not work on 486
423506f1d07SSam Ravnborg	  architectures. Similarly, multiprocessor kernels for the "PPro"
424506f1d07SSam Ravnborg	  architecture may not work on all Pentium based boards.
425506f1d07SSam Ravnborg
426506f1d07SSam Ravnborg	  People using multiprocessor machines who say Y here should also say
427506f1d07SSam Ravnborg	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
428506f1d07SSam Ravnborg	  Management" code will be disabled if you say Y here.
429506f1d07SSam Ravnborg
430cb1aaebeSMauro Carvalho Chehab	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
4314f4cfa6cSMauro Carvalho Chehab	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
432506f1d07SSam Ravnborg	  <http://www.tldp.org/docs.html#howto>.
433506f1d07SSam Ravnborg
434506f1d07SSam Ravnborg	  If you don't know what to do here, say N.
435506f1d07SSam Ravnborg
4369def39beSJosh Triplettconfig X86_FEATURE_NAMES
4379def39beSJosh Triplett	bool "Processor feature human-readable names" if EMBEDDED
4389def39beSJosh Triplett	default y
439a7f7f624SMasahiro Yamada	help
4409def39beSJosh Triplett	  This option compiles in a table of x86 feature bits and corresponding
4419def39beSJosh Triplett	  names.  This is required to support /proc/cpuinfo and a few kernel
4429def39beSJosh Triplett	  messages.  You can disable this to save space, at the expense of
4439def39beSJosh Triplett	  making those few kernel messages show numeric feature bits instead.
4449def39beSJosh Triplett
4459def39beSJosh Triplett	  If in doubt, say Y.
4469def39beSJosh Triplett
44706cd9a7dSYinghai Luconfig X86_X2APIC
44806cd9a7dSYinghai Lu	bool "Support x2apic"
44919e3d60dSJan Kiszka	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
450a7f7f624SMasahiro Yamada	help
45106cd9a7dSYinghai Lu	  This enables x2apic support on CPUs that have this feature.
45206cd9a7dSYinghai Lu
45306cd9a7dSYinghai Lu	  This allows 32-bit apic IDs (so it can support very large systems),
45406cd9a7dSYinghai Lu	  and accesses the local apic via MSRs not via mmio.
45506cd9a7dSYinghai Lu
45606cd9a7dSYinghai Lu	  If you don't know what to do here, say N.
45706cd9a7dSYinghai Lu
4586695c85bSYinghai Luconfig X86_MPPARSE
4594590d98fSAndy Shevchenko	bool "Enable MPS table" if ACPI
4607a527688SJan Beulich	default y
4615ab74722SIngo Molnar	depends on X86_LOCAL_APIC
462a7f7f624SMasahiro Yamada	help
4636695c85bSYinghai Lu	  For old smp systems that do not have proper acpi support. Newer systems
4646695c85bSYinghai Lu	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
4656695c85bSYinghai Lu
466ddd70cf9SJun Nakajimaconfig GOLDFISH
467ddd70cf9SJun Nakajima	def_bool y
468ddd70cf9SJun Nakajima	depends on X86_GOLDFISH
469ddd70cf9SJun Nakajima
470e6d42931SJohannes Weinerconfig X86_CPU_RESCTRL
471e6d42931SJohannes Weiner	bool "x86 CPU resource control support"
4726fe07ce3SBabu Moger	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
47359fe5a77SThomas Gleixner	select KERNFS
474e79f15a4SChen Yu	select PROC_CPU_RESCTRL		if PROC_FS
47578e99b4aSFenghua Yu	help
476e6d42931SJohannes Weiner	  Enable x86 CPU resource control support.
4776fe07ce3SBabu Moger
4786fe07ce3SBabu Moger	  Provide support for the allocation and monitoring of system resources
4796fe07ce3SBabu Moger	  usage by the CPU.
4806fe07ce3SBabu Moger
4816fe07ce3SBabu Moger	  Intel calls this Intel Resource Director Technology
4826fe07ce3SBabu Moger	  (Intel(R) RDT). More information about RDT can be found in the
4836fe07ce3SBabu Moger	  Intel x86 Architecture Software Developer Manual.
4846fe07ce3SBabu Moger
4856fe07ce3SBabu Moger	  AMD calls this AMD Platform Quality of Service (AMD QoS).
4866fe07ce3SBabu Moger	  More information about AMD QoS can be found in the AMD64 Technology
4876fe07ce3SBabu Moger	  Platform Quality of Service Extensions manual.
48878e99b4aSFenghua Yu
48978e99b4aSFenghua Yu	  Say N if unsure.
49078e99b4aSFenghua Yu
4918425091fSRavikiran G Thirumalaiif X86_32
492a0d0bb4dSRandy Dunlapconfig X86_BIGSMP
493a0d0bb4dSRandy Dunlap	bool "Support for big SMP systems with more than 8 CPUs"
494a0d0bb4dSRandy Dunlap	depends on SMP
495a7f7f624SMasahiro Yamada	help
496e133f6eaSRandy Dunlap	  This option is needed for the systems that have more than 8 CPUs.
497a0d0bb4dSRandy Dunlap
498c5c606d9SRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM
499c5c606d9SRavikiran G Thirumalai	bool "Support for extended (non-PC) x86 platforms"
500c5c606d9SRavikiran G Thirumalai	default y
501a7f7f624SMasahiro Yamada	help
50206ac8346SIngo Molnar	  If you disable this option then the kernel will only support
50306ac8346SIngo Molnar	  standard PC platforms. (which covers the vast majority of
50406ac8346SIngo Molnar	  systems out there.)
50506ac8346SIngo Molnar
5068425091fSRavikiran G Thirumalai	  If you enable this option then you'll be able to select support
5078425091fSRavikiran G Thirumalai	  for the following (non-PC) 32 bit x86 platforms:
508cb7b8023SBen Hutchings		Goldfish (Android emulator)
5098425091fSRavikiran G Thirumalai		AMD Elan
5108425091fSRavikiran G Thirumalai		RDC R-321x SoC
5118425091fSRavikiran G Thirumalai		SGI 320/540 (Visual Workstation)
51283125a3aSAlessandro Rubini		STA2X11-based (e.g. Northville)
5133f4110a4SThomas Gleixner		Moorestown MID devices
51406ac8346SIngo Molnar
51506ac8346SIngo Molnar	  If you have one of these systems, or if you want to build a
51606ac8346SIngo Molnar	  generic distribution kernel, say Y here - otherwise say N.
517758cd94aSJuerg Haefligerendif # X86_32
51806ac8346SIngo Molnar
5198425091fSRavikiran G Thirumalaiif X86_64
5208425091fSRavikiran G Thirumalaiconfig X86_EXTENDED_PLATFORM
5218425091fSRavikiran G Thirumalai	bool "Support for extended (non-PC) x86 platforms"
5228425091fSRavikiran G Thirumalai	default y
523a7f7f624SMasahiro Yamada	help
5248425091fSRavikiran G Thirumalai	  If you disable this option then the kernel will only support
5258425091fSRavikiran G Thirumalai	  standard PC platforms. (which covers the vast majority of
5268425091fSRavikiran G Thirumalai	  systems out there.)
5278425091fSRavikiran G Thirumalai
5288425091fSRavikiran G Thirumalai	  If you enable this option then you'll be able to select support
5298425091fSRavikiran G Thirumalai	  for the following (non-PC) 64 bit x86 platforms:
53044b111b5SSteffen Persvold		Numascale NumaChip
5318425091fSRavikiran G Thirumalai		ScaleMP vSMP
5328425091fSRavikiran G Thirumalai		SGI Ultraviolet
5338425091fSRavikiran G Thirumalai
5348425091fSRavikiran G Thirumalai	  If you have one of these systems, or if you want to build a
5358425091fSRavikiran G Thirumalai	  generic distribution kernel, say Y here - otherwise say N.
536758cd94aSJuerg Haefligerendif # X86_64
537c5c606d9SRavikiran G Thirumalai# This is an alphabetically sorted list of 64 bit extended platforms
538c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions
53944b111b5SSteffen Persvoldconfig X86_NUMACHIP
54044b111b5SSteffen Persvold	bool "Numascale NumaChip"
54144b111b5SSteffen Persvold	depends on X86_64
54244b111b5SSteffen Persvold	depends on X86_EXTENDED_PLATFORM
54344b111b5SSteffen Persvold	depends on NUMA
54444b111b5SSteffen Persvold	depends on SMP
54544b111b5SSteffen Persvold	depends on X86_X2APIC
546f9726bfdSDaniel J Blueman	depends on PCI_MMCONFIG
547a7f7f624SMasahiro Yamada	help
54844b111b5SSteffen Persvold	  Adds support for Numascale NumaChip large-SMP systems. Needed to
54944b111b5SSteffen Persvold	  enable more than ~168 cores.
55044b111b5SSteffen Persvold	  If you don't have one of these, you should say N here.
55103b48632SNick Piggin
5526a48565eSIngo Molnarconfig X86_VSMP
553c5c606d9SRavikiran G Thirumalai	bool "ScaleMP vSMP"
5546276a074SBorislav Petkov	select HYPERVISOR_GUEST
5556a48565eSIngo Molnar	select PARAVIRT
5566a48565eSIngo Molnar	depends on X86_64 && PCI
557c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
558ead91d4bSShai Fultheim	depends on SMP
559a7f7f624SMasahiro Yamada	help
5606a48565eSIngo Molnar	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
5616a48565eSIngo Molnar	  supposed to run on these EM64T-based machines.  Only choose this option
5626a48565eSIngo Molnar	  if you have one of these machines.
5636a48565eSIngo Molnar
564c5c606d9SRavikiran G Thirumalaiconfig X86_UV
565c5c606d9SRavikiran G Thirumalai	bool "SGI Ultraviolet"
566c5c606d9SRavikiran G Thirumalai	depends on X86_64
567c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
56854c28d29SJack Steiner	depends on NUMA
5691ecb4ae5SAndrew Morton	depends on EFI
570c2209ea5SIngo Molnar	depends on KEXEC_CORE
5719d6c26e7SSuresh Siddha	depends on X86_X2APIC
5721222e564SIngo Molnar	depends on PCI
573a7f7f624SMasahiro Yamada	help
574c5c606d9SRavikiran G Thirumalai	  This option is needed in order to support SGI Ultraviolet systems.
575c5c606d9SRavikiran G Thirumalai	  If you don't have one of these, you should say N here.
576c5c606d9SRavikiran G Thirumalai
577c5c606d9SRavikiran G Thirumalai# Following is an alphabetically sorted list of 32 bit extended platforms
578c5c606d9SRavikiran G Thirumalai# Please maintain the alphabetic order if and when there are additions
579506f1d07SSam Ravnborg
580ddd70cf9SJun Nakajimaconfig X86_GOLDFISH
581ddd70cf9SJun Nakajima	bool "Goldfish (Virtual Platform)"
582cb7b8023SBen Hutchings	depends on X86_EXTENDED_PLATFORM
583a7f7f624SMasahiro Yamada	help
584ddd70cf9SJun Nakajima	  Enable support for the Goldfish virtual platform used primarily
585ddd70cf9SJun Nakajima	  for Android development. Unless you are building for the Android
586ddd70cf9SJun Nakajima	  Goldfish emulator say N here.
587ddd70cf9SJun Nakajima
588c751e17bSThomas Gleixnerconfig X86_INTEL_CE
589c751e17bSThomas Gleixner	bool "CE4100 TV platform"
590c751e17bSThomas Gleixner	depends on PCI
591c751e17bSThomas Gleixner	depends on PCI_GODIRECT
5926084a6e2SJiang Liu	depends on X86_IO_APIC
593c751e17bSThomas Gleixner	depends on X86_32
594c751e17bSThomas Gleixner	depends on X86_EXTENDED_PLATFORM
59537bc9f50SDirk Brandewie	select X86_REBOOTFIXUPS
596da6b737bSSebastian Andrzej Siewior	select OF
597da6b737bSSebastian Andrzej Siewior	select OF_EARLY_FLATTREE
598a7f7f624SMasahiro Yamada	help
599c751e17bSThomas Gleixner	  Select for the Intel CE media processor (CE4100) SOC.
600c751e17bSThomas Gleixner	  This option compiles in support for the CE4100 SOC for settop
601c751e17bSThomas Gleixner	  boxes and media devices.
602c751e17bSThomas Gleixner
6034cb9b00fSDavid Cohenconfig X86_INTEL_MID
60443605ef1SAlan Cox	bool "Intel MID platform support"
60543605ef1SAlan Cox	depends on X86_EXTENDED_PLATFORM
606edc6bc78SDavid Cohen	depends on X86_PLATFORM_DEVICES
6071ea7c673SAlan Cox	depends on PCI
6083fda5bb4SAndy Shevchenko	depends on X86_64 || (PCI_GOANY && X86_32)
6091ea7c673SAlan Cox	depends on X86_IO_APIC
6104cb9b00fSDavid Cohen	select I2C
6117c9c3a1eSAlan Cox	select DW_APB_TIMER
61254b34aa0SMika Westerberg	select INTEL_SCU_PCI
613a7f7f624SMasahiro Yamada	help
6144cb9b00fSDavid Cohen	  Select to build a kernel capable of supporting Intel MID (Mobile
6154cb9b00fSDavid Cohen	  Internet Device) platform systems which do not have the PCI legacy
6164cb9b00fSDavid Cohen	  interfaces. If you are building for a PC class system say N here.
6171ea7c673SAlan Cox
6184cb9b00fSDavid Cohen	  Intel MID platforms are based on an Intel processor and chipset which
6194cb9b00fSDavid Cohen	  consume less power than most of the x86 derivatives.
62043605ef1SAlan Cox
6218bbc2a13SBryan O'Donoghueconfig X86_INTEL_QUARK
6228bbc2a13SBryan O'Donoghue	bool "Intel Quark platform support"
6238bbc2a13SBryan O'Donoghue	depends on X86_32
6248bbc2a13SBryan O'Donoghue	depends on X86_EXTENDED_PLATFORM
6258bbc2a13SBryan O'Donoghue	depends on X86_PLATFORM_DEVICES
6268bbc2a13SBryan O'Donoghue	depends on X86_TSC
6278bbc2a13SBryan O'Donoghue	depends on PCI
6288bbc2a13SBryan O'Donoghue	depends on PCI_GOANY
6298bbc2a13SBryan O'Donoghue	depends on X86_IO_APIC
6308bbc2a13SBryan O'Donoghue	select IOSF_MBI
6318bbc2a13SBryan O'Donoghue	select INTEL_IMR
6329ab6eb51SAndy Shevchenko	select COMMON_CLK
633a7f7f624SMasahiro Yamada	help
6348bbc2a13SBryan O'Donoghue	  Select to include support for Quark X1000 SoC.
6358bbc2a13SBryan O'Donoghue	  Say Y here if you have a Quark based system such as the Arduino
6368bbc2a13SBryan O'Donoghue	  compatible Intel Galileo.
6378bbc2a13SBryan O'Donoghue
6383d48aab1SMika Westerbergconfig X86_INTEL_LPSS
6393d48aab1SMika Westerberg	bool "Intel Low Power Subsystem Support"
6405962dd22SSinan Kaya	depends on X86 && ACPI && PCI
6413d48aab1SMika Westerberg	select COMMON_CLK
6420f531431SMathias Nyman	select PINCTRL
643eebb3e8dSAndy Shevchenko	select IOSF_MBI
644a7f7f624SMasahiro Yamada	help
6453d48aab1SMika Westerberg	  Select to build support for Intel Low Power Subsystem such as
6463d48aab1SMika Westerberg	  found on Intel Lynxpoint PCH. Selecting this option enables
6470f531431SMathias Nyman	  things like clock tree (common clock framework) and pincontrol
6480f531431SMathias Nyman	  which are needed by the LPSS peripheral drivers.
6493d48aab1SMika Westerberg
65092082a88SKen Xueconfig X86_AMD_PLATFORM_DEVICE
65192082a88SKen Xue	bool "AMD ACPI2Platform devices support"
65292082a88SKen Xue	depends on ACPI
65392082a88SKen Xue	select COMMON_CLK
65492082a88SKen Xue	select PINCTRL
655a7f7f624SMasahiro Yamada	help
65692082a88SKen Xue	  Select to interpret AMD specific ACPI device to platform device
65792082a88SKen Xue	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
65892082a88SKen Xue	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
65992082a88SKen Xue	  implemented under PINCTRL subsystem.
66092082a88SKen Xue
661ced3ce76SDavid E. Boxconfig IOSF_MBI
662ced3ce76SDavid E. Box	tristate "Intel SoC IOSF Sideband support for SoC platforms"
663ced3ce76SDavid E. Box	depends on PCI
664a7f7f624SMasahiro Yamada	help
665ced3ce76SDavid E. Box	  This option enables sideband register access support for Intel SoC
666ced3ce76SDavid E. Box	  platforms. On these platforms the IOSF sideband is used in lieu of
667ced3ce76SDavid E. Box	  MSR's for some register accesses, mostly but not limited to thermal
668ced3ce76SDavid E. Box	  and power. Drivers may query the availability of this device to
669ced3ce76SDavid E. Box	  determine if they need the sideband in order to work on these
670ced3ce76SDavid E. Box	  platforms. The sideband is available on the following SoC products.
671ced3ce76SDavid E. Box	  This list is not meant to be exclusive.
672ced3ce76SDavid E. Box	   - BayTrail
673ced3ce76SDavid E. Box	   - Braswell
674ced3ce76SDavid E. Box	   - Quark
675ced3ce76SDavid E. Box
676ced3ce76SDavid E. Box	  You should say Y if you are running a kernel on one of these SoC's.
677ced3ce76SDavid E. Box
678ed2226bdSDavid E. Boxconfig IOSF_MBI_DEBUG
679ed2226bdSDavid E. Box	bool "Enable IOSF sideband access through debugfs"
680ed2226bdSDavid E. Box	depends on IOSF_MBI && DEBUG_FS
681a7f7f624SMasahiro Yamada	help
682ed2226bdSDavid E. Box	  Select this option to expose the IOSF sideband access registers (MCR,
683ed2226bdSDavid E. Box	  MDR, MCRX) through debugfs to write and read register information from
684ed2226bdSDavid E. Box	  different units on the SoC. This is most useful for obtaining device
685ed2226bdSDavid E. Box	  state information for debug and analysis. As this is a general access
686ed2226bdSDavid E. Box	  mechanism, users of this option would have specific knowledge of the
687ed2226bdSDavid E. Box	  device they want to access.
688ed2226bdSDavid E. Box
689ed2226bdSDavid E. Box	  If you don't require the option or are in doubt, say N.
690ed2226bdSDavid E. Box
691c5c606d9SRavikiran G Thirumalaiconfig X86_RDC321X
692c5c606d9SRavikiran G Thirumalai	bool "RDC R-321x SoC"
693506f1d07SSam Ravnborg	depends on X86_32
694c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
695c5c606d9SRavikiran G Thirumalai	select M486
696c5c606d9SRavikiran G Thirumalai	select X86_REBOOTFIXUPS
697a7f7f624SMasahiro Yamada	help
698c5c606d9SRavikiran G Thirumalai	  This option is needed for RDC R-321x system-on-chip, also known
699c5c606d9SRavikiran G Thirumalai	  as R-8610-(G).
700c5c606d9SRavikiran G Thirumalai	  If you don't have one of these chips, you should say N here.
701c5c606d9SRavikiran G Thirumalai
702e0c7ae37SIngo Molnarconfig X86_32_NON_STANDARD
7039c398017SIngo Molnar	bool "Support non-standard 32-bit SMP architectures"
7049c398017SIngo Molnar	depends on X86_32 && SMP
705c5c606d9SRavikiran G Thirumalai	depends on X86_EXTENDED_PLATFORM
706a7f7f624SMasahiro Yamada	help
707b5660ba7SH. Peter Anvin	  This option compiles in the bigsmp and STA2X11 default
708b5660ba7SH. Peter Anvin	  subarchitectures.  It is intended for a generic binary
709b5660ba7SH. Peter Anvin	  kernel. If you select them all, kernel will probe it one by
710b5660ba7SH. Peter Anvin	  one and will fallback to default.
711d49c4288SYinghai Lu
712c5c606d9SRavikiran G Thirumalai# Alphabetically sorted list of Non standard 32 bit platforms
713d49c4288SYinghai Lu
714d949f36fSLinus Torvaldsconfig X86_SUPPORTS_MEMORY_FAILURE
7156fc108a0SJan Beulich	def_bool y
716d949f36fSLinus Torvalds	# MCE code calls memory_failure():
717d949f36fSLinus Torvalds	depends on X86_MCE
718d949f36fSLinus Torvalds	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
719d949f36fSLinus Torvalds	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
720d949f36fSLinus Torvalds	depends on X86_64 || !SPARSEMEM
721d949f36fSLinus Torvalds	select ARCH_SUPPORTS_MEMORY_FAILURE
722d949f36fSLinus Torvalds
72383125a3aSAlessandro Rubiniconfig STA2X11
72483125a3aSAlessandro Rubini	bool "STA2X11 Companion Chip Support"
72583125a3aSAlessandro Rubini	depends on X86_32_NON_STANDARD && PCI
72683125a3aSAlessandro Rubini	select SWIOTLB
72783125a3aSAlessandro Rubini	select MFD_STA2X11
7280145071bSLinus Walleij	select GPIOLIB
729a7f7f624SMasahiro Yamada	help
73083125a3aSAlessandro Rubini	  This adds support for boards based on the STA2X11 IO-Hub,
73183125a3aSAlessandro Rubini	  a.k.a. "ConneXt". The chip is used in place of the standard
73283125a3aSAlessandro Rubini	  PC chipset, so all "standard" peripherals are missing. If this
73383125a3aSAlessandro Rubini	  option is selected the kernel will still be able to boot on
73483125a3aSAlessandro Rubini	  standard PC machines.
73583125a3aSAlessandro Rubini
73682148d1dSShérabconfig X86_32_IRIS
73782148d1dSShérab	tristate "Eurobraille/Iris poweroff module"
73882148d1dSShérab	depends on X86_32
739a7f7f624SMasahiro Yamada	help
74082148d1dSShérab	  The Iris machines from EuroBraille do not have APM or ACPI support
74182148d1dSShérab	  to shut themselves down properly.  A special I/O sequence is
74282148d1dSShérab	  needed to do so, which is what this module does at
74382148d1dSShérab	  kernel shutdown.
74482148d1dSShérab
74582148d1dSShérab	  This is only for Iris machines from EuroBraille.
74682148d1dSShérab
74782148d1dSShérab	  If unused, say N.
74882148d1dSShérab
749ae1e9130SIngo Molnarconfig SCHED_OMIT_FRAME_POINTER
7503c2362e6SHarvey Harrison	def_bool y
7513c2362e6SHarvey Harrison	prompt "Single-depth WCHAN output"
752a87d0914SKen Chen	depends on X86
753a7f7f624SMasahiro Yamada	help
754506f1d07SSam Ravnborg	  Calculate simpler /proc/<PID>/wchan values. If this option
755506f1d07SSam Ravnborg	  is disabled then wchan values will recurse back to the
756506f1d07SSam Ravnborg	  caller function. This provides more accurate wchan values,
757506f1d07SSam Ravnborg	  at the expense of slightly more scheduling overhead.
758506f1d07SSam Ravnborg
759506f1d07SSam Ravnborg	  If in doubt, say "Y".
760506f1d07SSam Ravnborg
7616276a074SBorislav Petkovmenuconfig HYPERVISOR_GUEST
7626276a074SBorislav Petkov	bool "Linux guest support"
763a7f7f624SMasahiro Yamada	help
7646276a074SBorislav Petkov	  Say Y here to enable options for running Linux under various hyper-
7656276a074SBorislav Petkov	  visors. This option enables basic hypervisor detection and platform
7666276a074SBorislav Petkov	  setup.
767506f1d07SSam Ravnborg
7686276a074SBorislav Petkov	  If you say N, all options in this submenu will be skipped and
7696276a074SBorislav Petkov	  disabled, and Linux guest support won't be built in.
770506f1d07SSam Ravnborg
7716276a074SBorislav Petkovif HYPERVISOR_GUEST
772506f1d07SSam Ravnborg
773e61bd94aSEduardo Pereira Habkostconfig PARAVIRT
774e61bd94aSEduardo Pereira Habkost	bool "Enable paravirtualization code"
775a0e2bf7cSJuergen Gross	depends on HAVE_STATIC_CALL
776a7f7f624SMasahiro Yamada	help
777e61bd94aSEduardo Pereira Habkost	  This changes the kernel so it can modify itself when it is run
778e61bd94aSEduardo Pereira Habkost	  under a hypervisor, potentially improving performance significantly
779e61bd94aSEduardo Pereira Habkost	  over full virtualization.  However, when run without a hypervisor
780e61bd94aSEduardo Pereira Habkost	  the kernel is theoretically slower and slightly larger.
781e61bd94aSEduardo Pereira Habkost
782c00a280aSJuergen Grossconfig PARAVIRT_XXL
783c00a280aSJuergen Gross	bool
784c00a280aSJuergen Gross
7856276a074SBorislav Petkovconfig PARAVIRT_DEBUG
7866276a074SBorislav Petkov	bool "paravirt-ops debugging"
7876276a074SBorislav Petkov	depends on PARAVIRT && DEBUG_KERNEL
788a7f7f624SMasahiro Yamada	help
7896276a074SBorislav Petkov	  Enable to debug paravirt_ops internals.  Specifically, BUG if
7906276a074SBorislav Petkov	  a paravirt_op is missing when it is called.
7916276a074SBorislav Petkov
792b4ecc126SJeremy Fitzhardingeconfig PARAVIRT_SPINLOCKS
793b4ecc126SJeremy Fitzhardinge	bool "Paravirtualization layer for spinlocks"
7946ea30386SKees Cook	depends on PARAVIRT && SMP
795a7f7f624SMasahiro Yamada	help
796b4ecc126SJeremy Fitzhardinge	  Paravirtualized spinlocks allow a pvops backend to replace the
797b4ecc126SJeremy Fitzhardinge	  spinlock implementation with something virtualization-friendly
798b4ecc126SJeremy Fitzhardinge	  (for example, block the virtual CPU rather than spinning).
799b4ecc126SJeremy Fitzhardinge
8004c4e4f61SRaghavendra K T	  It has a minimal impact on native kernels and gives a nice performance
8014c4e4f61SRaghavendra K T	  benefit on paravirtualized KVM / Xen kernels.
802b4ecc126SJeremy Fitzhardinge
8034c4e4f61SRaghavendra K T	  If you are unsure how to answer this question, answer Y.
804b4ecc126SJeremy Fitzhardinge
805ecca2502SZhao Yakuiconfig X86_HV_CALLBACK_VECTOR
806ecca2502SZhao Yakui	def_bool n
807ecca2502SZhao Yakui
8086276a074SBorislav Petkovsource "arch/x86/xen/Kconfig"
8096276a074SBorislav Petkov
8106276a074SBorislav Petkovconfig KVM_GUEST
8116276a074SBorislav Petkov	bool "KVM Guest support (including kvmclock)"
8126276a074SBorislav Petkov	depends on PARAVIRT
8136276a074SBorislav Petkov	select PARAVIRT_CLOCK
814a1c4423bSMarcelo Tosatti	select ARCH_CPUIDLE_HALTPOLL
815b1d40575SVitaly Kuznetsov	select X86_HV_CALLBACK_VECTOR
8166276a074SBorislav Petkov	default y
817a7f7f624SMasahiro Yamada	help
8186276a074SBorislav Petkov	  This option enables various optimizations for running under the KVM
8196276a074SBorislav Petkov	  hypervisor. It includes a paravirtualized clock, so that instead
8206276a074SBorislav Petkov	  of relying on a PIT (or probably other) emulation by the
8216276a074SBorislav Petkov	  underlying device model, the host provides the guest with
8226276a074SBorislav Petkov	  timing infrastructure such as time of day, and system time
8236276a074SBorislav Petkov
824a1c4423bSMarcelo Tosatticonfig ARCH_CPUIDLE_HALTPOLL
825a1c4423bSMarcelo Tosatti	def_bool n
826a1c4423bSMarcelo Tosatti	prompt "Disable host haltpoll when loading haltpoll driver"
827a1c4423bSMarcelo Tosatti	help
828a1c4423bSMarcelo Tosatti	  If virtualized under KVM, disable host haltpoll.
829a1c4423bSMarcelo Tosatti
8307733607fSMaran Wilsonconfig PVH
8317733607fSMaran Wilson	bool "Support for running PVH guests"
832a7f7f624SMasahiro Yamada	help
8337733607fSMaran Wilson	  This option enables the PVH entry point for guest virtual machines
8347733607fSMaran Wilson	  as specified in the x86/HVM direct boot ABI.
8357733607fSMaran Wilson
8366276a074SBorislav Petkovconfig PARAVIRT_TIME_ACCOUNTING
8376276a074SBorislav Petkov	bool "Paravirtual steal time accounting"
8386276a074SBorislav Petkov	depends on PARAVIRT
839a7f7f624SMasahiro Yamada	help
8406276a074SBorislav Petkov	  Select this option to enable fine granularity task steal time
8416276a074SBorislav Petkov	  accounting. Time spent executing other tasks in parallel with
8426276a074SBorislav Petkov	  the current vCPU is discounted from the vCPU power. To account for
8436276a074SBorislav Petkov	  that, there can be a small performance impact.
8446276a074SBorislav Petkov
8456276a074SBorislav Petkov	  If in doubt, say N here.
8466276a074SBorislav Petkov
8477af192c9SGerd Hoffmannconfig PARAVIRT_CLOCK
8487af192c9SGerd Hoffmann	bool
8497af192c9SGerd Hoffmann
8504a362601SJan Kiszkaconfig JAILHOUSE_GUEST
8514a362601SJan Kiszka	bool "Jailhouse non-root cell support"
852abde587bSArnd Bergmann	depends on X86_64 && PCI
85387e65d05SJan Kiszka	select X86_PM_TIMER
854a7f7f624SMasahiro Yamada	help
8554a362601SJan Kiszka	  This option allows to run Linux as guest in a Jailhouse non-root
8564a362601SJan Kiszka	  cell. You can leave this option disabled if you only want to start
8574a362601SJan Kiszka	  Jailhouse and run Linux afterwards in the root cell.
8584a362601SJan Kiszka
859ec7972c9SZhao Yakuiconfig ACRN_GUEST
860ec7972c9SZhao Yakui	bool "ACRN Guest support"
861ec7972c9SZhao Yakui	depends on X86_64
862498ad393SZhao Yakui	select X86_HV_CALLBACK_VECTOR
863ec7972c9SZhao Yakui	help
864ec7972c9SZhao Yakui	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
865ec7972c9SZhao Yakui	  a flexible, lightweight reference open-source hypervisor, built with
866ec7972c9SZhao Yakui	  real-time and safety-criticality in mind. It is built for embedded
867ec7972c9SZhao Yakui	  IOT with small footprint and real-time features. More details can be
868ec7972c9SZhao Yakui	  found in https://projectacrn.org/.
869ec7972c9SZhao Yakui
87059bd54a8SKuppuswamy Sathyanarayananconfig INTEL_TDX_GUEST
87159bd54a8SKuppuswamy Sathyanarayanan	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
87259bd54a8SKuppuswamy Sathyanarayanan	depends on X86_64 && CPU_SUP_INTEL
87359bd54a8SKuppuswamy Sathyanarayanan	depends on X86_X2APIC
87441394e33SKirill A. Shutemov	select ARCH_HAS_CC_PLATFORM
875968b4931SKirill A. Shutemov	select X86_MEM_ENCRYPT
87677a512e3SSean Christopherson	select X86_MCE
87759bd54a8SKuppuswamy Sathyanarayanan	help
87859bd54a8SKuppuswamy Sathyanarayanan	  Support running as a guest under Intel TDX.  Without this support,
87959bd54a8SKuppuswamy Sathyanarayanan	  the guest kernel can not boot or run under TDX.
88059bd54a8SKuppuswamy Sathyanarayanan	  TDX includes memory encryption and integrity capabilities
88159bd54a8SKuppuswamy Sathyanarayanan	  which protect the confidentiality and integrity of guest
88259bd54a8SKuppuswamy Sathyanarayanan	  memory contents and CPU state. TDX guests are protected from
88359bd54a8SKuppuswamy Sathyanarayanan	  some attacks from the VMM.
88459bd54a8SKuppuswamy Sathyanarayanan
8856276a074SBorislav Petkovendif # HYPERVISOR_GUEST
88697349135SJeremy Fitzhardinge
887506f1d07SSam Ravnborgsource "arch/x86/Kconfig.cpu"
888506f1d07SSam Ravnborg
889506f1d07SSam Ravnborgconfig HPET_TIMER
8903c2362e6SHarvey Harrison	def_bool X86_64
891506f1d07SSam Ravnborg	prompt "HPET Timer Support" if X86_32
892a7f7f624SMasahiro Yamada	help
893506f1d07SSam Ravnborg	  Use the IA-PC HPET (High Precision Event Timer) to manage
894506f1d07SSam Ravnborg	  time in preference to the PIT and RTC, if a HPET is
895506f1d07SSam Ravnborg	  present.
896506f1d07SSam Ravnborg	  HPET is the next generation timer replacing legacy 8254s.
897506f1d07SSam Ravnborg	  The HPET provides a stable time base on SMP
898506f1d07SSam Ravnborg	  systems, unlike the TSC, but it is more expensive to access,
8994e7f9df2SMichael S. Tsirkin	  as it is off-chip.  The interface used is documented
9004e7f9df2SMichael S. Tsirkin	  in the HPET spec, revision 1.
901506f1d07SSam Ravnborg
902506f1d07SSam Ravnborg	  You can safely choose Y here.  However, HPET will only be
903506f1d07SSam Ravnborg	  activated if the platform and the BIOS support this feature.
904506f1d07SSam Ravnborg	  Otherwise the 8254 will be used for timing services.
905506f1d07SSam Ravnborg
906506f1d07SSam Ravnborg	  Choose N to continue using the legacy 8254 timer.
907506f1d07SSam Ravnborg
908506f1d07SSam Ravnborgconfig HPET_EMULATE_RTC
9093c2362e6SHarvey Harrison	def_bool y
9103228e1dcSAnand K Mistry	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
911506f1d07SSam Ravnborg
9126a108a14SDavid Rientjes# Mark as expert because too many people got it wrong.
913506f1d07SSam Ravnborg# The code disables itself when not needed.
9147ae9392cSThomas Petazzoniconfig DMI
9157ae9392cSThomas Petazzoni	default y
916cf074402SArd Biesheuvel	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
9176a108a14SDavid Rientjes	bool "Enable DMI scanning" if EXPERT
918a7f7f624SMasahiro Yamada	help
9197ae9392cSThomas Petazzoni	  Enabled scanning of DMI to identify machine quirks. Say Y
9207ae9392cSThomas Petazzoni	  here unless you have verified that your setup is not
9217ae9392cSThomas Petazzoni	  affected by entries in the DMI blacklist. Required by PNP
9227ae9392cSThomas Petazzoni	  BIOS code.
9237ae9392cSThomas Petazzoni
924506f1d07SSam Ravnborgconfig GART_IOMMU
92538901f1cSAndi Kleen	bool "Old AMD GART IOMMU support"
9262f9237d4SChristoph Hellwig	select DMA_OPS
927a4ce5a48SChristoph Hellwig	select IOMMU_HELPER
928506f1d07SSam Ravnborg	select SWIOTLB
92923ac4ae8SAndreas Herrmann	depends on X86_64 && PCI && AMD_NB
930a7f7f624SMasahiro Yamada	help
931ced3c42cSIngo Molnar	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
932ced3c42cSIngo Molnar	  GART based hardware IOMMUs.
933ced3c42cSIngo Molnar
934ced3c42cSIngo Molnar	  The GART supports full DMA access for devices with 32-bit access
935ced3c42cSIngo Molnar	  limitations, on systems with more than 3 GB. This is usually needed
936ced3c42cSIngo Molnar	  for USB, sound, many IDE/SATA chipsets and some other devices.
937ced3c42cSIngo Molnar
938ced3c42cSIngo Molnar	  Newer systems typically have a modern AMD IOMMU, supported via
939ced3c42cSIngo Molnar	  the CONFIG_AMD_IOMMU=y config option.
940ced3c42cSIngo Molnar
941ced3c42cSIngo Molnar	  In normal configurations this driver is only active when needed:
942ced3c42cSIngo Molnar	  there's more than 3 GB of memory and the system contains a
943ced3c42cSIngo Molnar	  32-bit limited device.
944ced3c42cSIngo Molnar
945ced3c42cSIngo Molnar	  If unsure, say Y.
946506f1d07SSam Ravnborg
9478b766b0fSMichal Suchanekconfig BOOT_VESA_SUPPORT
9488b766b0fSMichal Suchanek	bool
9498b766b0fSMichal Suchanek	help
9508b766b0fSMichal Suchanek	  If true, at least one selected framebuffer driver can take advantage
9518b766b0fSMichal Suchanek	  of VESA video modes set at an early boot stage via the vga= parameter.
9528b766b0fSMichal Suchanek
9531184dc2fSMike Travisconfig MAXSMP
954ddb0c5a6SSamuel Thibault	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
9556ea30386SKees Cook	depends on X86_64 && SMP && DEBUG_KERNEL
95636f5101aSMike Travis	select CPUMASK_OFFSTACK
957a7f7f624SMasahiro Yamada	help
958ddb0c5a6SSamuel Thibault	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
9591184dc2fSMike Travis	  If unsure, say N.
960506f1d07SSam Ravnborg
961aec6487eSIngo Molnar#
962aec6487eSIngo Molnar# The maximum number of CPUs supported:
963aec6487eSIngo Molnar#
964aec6487eSIngo Molnar# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
965aec6487eSIngo Molnar# and which can be configured interactively in the
966aec6487eSIngo Molnar# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
967aec6487eSIngo Molnar#
968aec6487eSIngo Molnar# The ranges are different on 32-bit and 64-bit kernels, depending on
969aec6487eSIngo Molnar# hardware capabilities and scalability features of the kernel.
970aec6487eSIngo Molnar#
971aec6487eSIngo Molnar# ( If MAXSMP is enabled we just use the highest possible value and disable
972aec6487eSIngo Molnar#   interactive configuration. )
973aec6487eSIngo Molnar#
974a0d0bb4dSRandy Dunlap
975aec6487eSIngo Molnarconfig NR_CPUS_RANGE_BEGIN
976a0d0bb4dSRandy Dunlap	int
977aec6487eSIngo Molnar	default NR_CPUS_RANGE_END if MAXSMP
978a0d0bb4dSRandy Dunlap	default    1 if !SMP
979a0d0bb4dSRandy Dunlap	default    2
980a0d0bb4dSRandy Dunlap
981aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END
982a0d0bb4dSRandy Dunlap	int
983a0d0bb4dSRandy Dunlap	depends on X86_32
984aec6487eSIngo Molnar	default   64 if  SMP &&  X86_BIGSMP
985aec6487eSIngo Molnar	default    8 if  SMP && !X86_BIGSMP
986a0d0bb4dSRandy Dunlap	default    1 if !SMP
987a0d0bb4dSRandy Dunlap
988aec6487eSIngo Molnarconfig NR_CPUS_RANGE_END
989a0d0bb4dSRandy Dunlap	int
990a0d0bb4dSRandy Dunlap	depends on X86_64
9911edae1aeSScott Wood	default 8192 if  SMP && CPUMASK_OFFSTACK
9921edae1aeSScott Wood	default  512 if  SMP && !CPUMASK_OFFSTACK
993a0d0bb4dSRandy Dunlap	default    1 if !SMP
994aec6487eSIngo Molnar
995aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT
996aec6487eSIngo Molnar	int
997aec6487eSIngo Molnar	depends on X86_32
998aec6487eSIngo Molnar	default   32 if  X86_BIGSMP
999aec6487eSIngo Molnar	default    8 if  SMP
1000aec6487eSIngo Molnar	default    1 if !SMP
1001aec6487eSIngo Molnar
1002aec6487eSIngo Molnarconfig NR_CPUS_DEFAULT
1003aec6487eSIngo Molnar	int
1004aec6487eSIngo Molnar	depends on X86_64
1005a0d0bb4dSRandy Dunlap	default 8192 if  MAXSMP
1006a0d0bb4dSRandy Dunlap	default   64 if  SMP
1007aec6487eSIngo Molnar	default    1 if !SMP
1008a0d0bb4dSRandy Dunlap
1009506f1d07SSam Ravnborgconfig NR_CPUS
101036f5101aSMike Travis	int "Maximum number of CPUs" if SMP && !MAXSMP
1011aec6487eSIngo Molnar	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1012aec6487eSIngo Molnar	default NR_CPUS_DEFAULT
1013a7f7f624SMasahiro Yamada	help
1014506f1d07SSam Ravnborg	  This allows you to specify the maximum number of CPUs which this
1015bb61ccc7SJosh Boyer	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1016cad14bb9SKirill A. Shutemov	  supported value is 8192, otherwise the maximum value is 512.  The
1017506f1d07SSam Ravnborg	  minimum value which makes sense is 2.
1018506f1d07SSam Ravnborg
1019aec6487eSIngo Molnar	  This is purely to save memory: each supported CPU adds about 8KB
1020aec6487eSIngo Molnar	  to the kernel image.
1021506f1d07SSam Ravnborg
102266558b73STim Chenconfig SCHED_CLUSTER
102366558b73STim Chen	bool "Cluster scheduler support"
102466558b73STim Chen	depends on SMP
102566558b73STim Chen	default y
102666558b73STim Chen	help
102766558b73STim Chen	  Cluster scheduler support improves the CPU scheduler's decision
102866558b73STim Chen	  making when dealing with machines that have clusters of CPUs.
102966558b73STim Chen	  Cluster usually means a couple of CPUs which are placed closely
103066558b73STim Chen	  by sharing mid-level caches, last-level cache tags or internal
103166558b73STim Chen	  busses.
103266558b73STim Chen
1033506f1d07SSam Ravnborgconfig SCHED_SMT
1034dbe73364SThomas Gleixner	def_bool y if SMP
1035506f1d07SSam Ravnborg
1036506f1d07SSam Ravnborgconfig SCHED_MC
10373c2362e6SHarvey Harrison	def_bool y
10383c2362e6SHarvey Harrison	prompt "Multi-core scheduler support"
1039c8e56d20SBorislav Petkov	depends on SMP
1040a7f7f624SMasahiro Yamada	help
1041506f1d07SSam Ravnborg	  Multi-core scheduler support improves the CPU scheduler's decision
1042506f1d07SSam Ravnborg	  making when dealing with multi-core CPU chips at a cost of slightly
1043506f1d07SSam Ravnborg	  increased overhead in some places. If unsure say N here.
1044506f1d07SSam Ravnborg
1045de966cf4STim Chenconfig SCHED_MC_PRIO
1046de966cf4STim Chen	bool "CPU core priorities scheduler support"
10470a21fc12SIngo Molnar	depends on SCHED_MC && CPU_SUP_INTEL
10480a21fc12SIngo Molnar	select X86_INTEL_PSTATE
10490a21fc12SIngo Molnar	select CPU_FREQ
1050de966cf4STim Chen	default y
1051a7f7f624SMasahiro Yamada	help
1052de966cf4STim Chen	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1053de966cf4STim Chen	  core ordering determined at manufacturing time, which allows
1054de966cf4STim Chen	  certain cores to reach higher turbo frequencies (when running
1055de966cf4STim Chen	  single threaded workloads) than others.
1056de966cf4STim Chen
1057de966cf4STim Chen	  Enabling this kernel feature teaches the scheduler about
1058de966cf4STim Chen	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1059de966cf4STim Chen	  scheduler's CPU selection logic accordingly, so that higher
1060de966cf4STim Chen	  overall system performance can be achieved.
1061de966cf4STim Chen
1062de966cf4STim Chen	  This feature will have no effect on CPUs without this feature.
1063de966cf4STim Chen
1064de966cf4STim Chen	  If unsure say Y here.
10655e76b2abSTim Chen
106630b8b006SThomas Gleixnerconfig UP_LATE_INIT
106730b8b006SThomas Gleixner	def_bool y
1068ba360f88SThomas Gleixner	depends on !SMP && X86_LOCAL_APIC
106930b8b006SThomas Gleixner
1070506f1d07SSam Ravnborgconfig X86_UP_APIC
107150849eefSJan Beulich	bool "Local APIC support on uniprocessors" if !PCI_MSI
107250849eefSJan Beulich	default PCI_MSI
107338a1dfdaSBryan O'Donoghue	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1074a7f7f624SMasahiro Yamada	help
1075506f1d07SSam Ravnborg	  A local APIC (Advanced Programmable Interrupt Controller) is an
1076506f1d07SSam Ravnborg	  integrated interrupt controller in the CPU. If you have a single-CPU
1077506f1d07SSam Ravnborg	  system which has a processor with a local APIC, you can say Y here to
1078506f1d07SSam Ravnborg	  enable and use it. If you say Y here even though your machine doesn't
1079506f1d07SSam Ravnborg	  have a local APIC, then the kernel will still run with no slowdown at
1080506f1d07SSam Ravnborg	  all. The local APIC supports CPU-generated self-interrupts (timer,
1081506f1d07SSam Ravnborg	  performance counters), and the NMI watchdog which detects hard
1082506f1d07SSam Ravnborg	  lockups.
1083506f1d07SSam Ravnborg
1084506f1d07SSam Ravnborgconfig X86_UP_IOAPIC
1085506f1d07SSam Ravnborg	bool "IO-APIC support on uniprocessors"
1086506f1d07SSam Ravnborg	depends on X86_UP_APIC
1087a7f7f624SMasahiro Yamada	help
1088506f1d07SSam Ravnborg	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1089506f1d07SSam Ravnborg	  SMP-capable replacement for PC-style interrupt controllers. Most
1090506f1d07SSam Ravnborg	  SMP systems and many recent uniprocessor systems have one.
1091506f1d07SSam Ravnborg
1092506f1d07SSam Ravnborg	  If you have a single-CPU system with an IO-APIC, you can say Y here
1093506f1d07SSam Ravnborg	  to use it. If you say Y here even though your machine doesn't have
1094506f1d07SSam Ravnborg	  an IO-APIC, then the kernel will still run with no slowdown at all.
1095506f1d07SSam Ravnborg
1096506f1d07SSam Ravnborgconfig X86_LOCAL_APIC
10973c2362e6SHarvey Harrison	def_bool y
10980dbc6078SThomas Petazzoni	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1099b5dc8e6cSJiang Liu	select IRQ_DOMAIN_HIERARCHY
110052f518a3SJiang Liu	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1101506f1d07SSam Ravnborg
1102506f1d07SSam Ravnborgconfig X86_IO_APIC
1103b1da1e71SJan Beulich	def_bool y
1104b1da1e71SJan Beulich	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1105506f1d07SSam Ravnborg
110641b9eb26SStefan Assmannconfig X86_REROUTE_FOR_BROKEN_BOOT_IRQS
110741b9eb26SStefan Assmann	bool "Reroute for broken boot IRQs"
110841b9eb26SStefan Assmann	depends on X86_IO_APIC
1109a7f7f624SMasahiro Yamada	help
111041b9eb26SStefan Assmann	  This option enables a workaround that fixes a source of
111141b9eb26SStefan Assmann	  spurious interrupts. This is recommended when threaded
111241b9eb26SStefan Assmann	  interrupt handling is used on systems where the generation of
111341b9eb26SStefan Assmann	  superfluous "boot interrupts" cannot be disabled.
111441b9eb26SStefan Assmann
111541b9eb26SStefan Assmann	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
111641b9eb26SStefan Assmann	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
111741b9eb26SStefan Assmann	  kernel does during interrupt handling). On chipsets where this
111841b9eb26SStefan Assmann	  boot IRQ generation cannot be disabled, this workaround keeps
111941b9eb26SStefan Assmann	  the original IRQ line masked so that only the equivalent "boot
112041b9eb26SStefan Assmann	  IRQ" is delivered to the CPUs. The workaround also tells the
112141b9eb26SStefan Assmann	  kernel to set up the IRQ handler on the boot IRQ line. In this
112241b9eb26SStefan Assmann	  way only one interrupt is delivered to the kernel. Otherwise
112341b9eb26SStefan Assmann	  the spurious second interrupt may cause the kernel to bring
112441b9eb26SStefan Assmann	  down (vital) interrupt lines.
112541b9eb26SStefan Assmann
112641b9eb26SStefan Assmann	  Only affects "broken" chipsets. Interrupt sharing may be
112741b9eb26SStefan Assmann	  increased on these systems.
112841b9eb26SStefan Assmann
1129506f1d07SSam Ravnborgconfig X86_MCE
1130bab9bc65SAndi Kleen	bool "Machine Check / overheating reporting"
1131648ed940SChen, Gong	select GENERIC_ALLOCATOR
1132e57dbaf7SBorislav Petkov	default y
1133a7f7f624SMasahiro Yamada	help
1134bab9bc65SAndi Kleen	  Machine Check support allows the processor to notify the
1135bab9bc65SAndi Kleen	  kernel if it detects a problem (e.g. overheating, data corruption).
1136506f1d07SSam Ravnborg	  The action the kernel takes depends on the severity of the problem,
1137bab9bc65SAndi Kleen	  ranging from warning messages to halting the machine.
11384efc0670SAndi Kleen
11395de97c9fSTony Luckconfig X86_MCELOG_LEGACY
11405de97c9fSTony Luck	bool "Support for deprecated /dev/mcelog character device"
11415de97c9fSTony Luck	depends on X86_MCE
1142a7f7f624SMasahiro Yamada	help
11435de97c9fSTony Luck	  Enable support for /dev/mcelog which is needed by the old mcelog
11445de97c9fSTony Luck	  userspace logging daemon. Consider switching to the new generation
11455de97c9fSTony Luck	  rasdaemon solution.
11465de97c9fSTony Luck
1147506f1d07SSam Ravnborgconfig X86_MCE_INTEL
11483c2362e6SHarvey Harrison	def_bool y
11493c2362e6SHarvey Harrison	prompt "Intel MCE features"
1150c1ebf835SAndi Kleen	depends on X86_MCE && X86_LOCAL_APIC
1151a7f7f624SMasahiro Yamada	help
1152506f1d07SSam Ravnborg	  Additional support for intel specific MCE features such as
1153506f1d07SSam Ravnborg	  the thermal monitor.
1154506f1d07SSam Ravnborg
1155506f1d07SSam Ravnborgconfig X86_MCE_AMD
11563c2362e6SHarvey Harrison	def_bool y
11573c2362e6SHarvey Harrison	prompt "AMD MCE features"
1158f5382de9SYazen Ghannam	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1159a7f7f624SMasahiro Yamada	help
1160506f1d07SSam Ravnborg	  Additional support for AMD specific MCE features such as
1161506f1d07SSam Ravnborg	  the DRAM Error Threshold.
1162506f1d07SSam Ravnborg
11634efc0670SAndi Kleenconfig X86_ANCIENT_MCE
11646fc108a0SJan Beulich	bool "Support for old Pentium 5 / WinChip machine checks"
1165c31d9633SAndi Kleen	depends on X86_32 && X86_MCE
1166a7f7f624SMasahiro Yamada	help
11674efc0670SAndi Kleen	  Include support for machine check handling on old Pentium 5 or WinChip
11685065a706SMasanari Iida	  systems. These typically need to be enabled explicitly on the command
11694efc0670SAndi Kleen	  line.
11704efc0670SAndi Kleen
1171b2762686SAndi Kleenconfig X86_MCE_THRESHOLD
1172b2762686SAndi Kleen	depends on X86_MCE_AMD || X86_MCE_INTEL
11736fc108a0SJan Beulich	def_bool y
1174b2762686SAndi Kleen
1175ea149b36SAndi Kleenconfig X86_MCE_INJECT
1176bc8e80d5SBorislav Petkov	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1177ea149b36SAndi Kleen	tristate "Machine check injector support"
1178a7f7f624SMasahiro Yamada	help
1179ea149b36SAndi Kleen	  Provide support for injecting machine checks for testing purposes.
1180ea149b36SAndi Kleen	  If you don't know what a machine check is and you don't do kernel
1181ea149b36SAndi Kleen	  QA it is safe to say n.
1182ea149b36SAndi Kleen
118307dc900eSPeter Zijlstrasource "arch/x86/events/Kconfig"
1184e633c65aSKan Liang
11855aef51c3SAndy Lutomirskiconfig X86_LEGACY_VM86
11861e642812SIngo Molnar	bool "Legacy VM86 support"
1187506f1d07SSam Ravnborg	depends on X86_32
1188a7f7f624SMasahiro Yamada	help
11895aef51c3SAndy Lutomirski	  This option allows user programs to put the CPU into V8086
11905aef51c3SAndy Lutomirski	  mode, which is an 80286-era approximation of 16-bit real mode.
11915aef51c3SAndy Lutomirski
11925aef51c3SAndy Lutomirski	  Some very old versions of X and/or vbetool require this option
11935aef51c3SAndy Lutomirski	  for user mode setting.  Similarly, DOSEMU will use it if
11945aef51c3SAndy Lutomirski	  available to accelerate real mode DOS programs.  However, any
11955aef51c3SAndy Lutomirski	  recent version of DOSEMU, X, or vbetool should be fully
11965aef51c3SAndy Lutomirski	  functional even without kernel VM86 support, as they will all
11971e642812SIngo Molnar	  fall back to software emulation. Nevertheless, if you are using
11981e642812SIngo Molnar	  a 16-bit DOS program where 16-bit performance matters, vm86
11991e642812SIngo Molnar	  mode might be faster than emulation and you might want to
12001e642812SIngo Molnar	  enable this option.
12015aef51c3SAndy Lutomirski
12021e642812SIngo Molnar	  Note that any app that works on a 64-bit kernel is unlikely to
12031e642812SIngo Molnar	  need this option, as 64-bit kernels don't, and can't, support
12041e642812SIngo Molnar	  V8086 mode. This option is also unrelated to 16-bit protected
12051e642812SIngo Molnar	  mode and is not needed to run most 16-bit programs under Wine.
12065aef51c3SAndy Lutomirski
12071e642812SIngo Molnar	  Enabling this option increases the complexity of the kernel
12081e642812SIngo Molnar	  and slows down exception handling a tiny bit.
12095aef51c3SAndy Lutomirski
12101e642812SIngo Molnar	  If unsure, say N here.
12115aef51c3SAndy Lutomirski
12125aef51c3SAndy Lutomirskiconfig VM86
12135aef51c3SAndy Lutomirski	bool
12145aef51c3SAndy Lutomirski	default X86_LEGACY_VM86
121534273f41SH. Peter Anvin
121634273f41SH. Peter Anvinconfig X86_16BIT
121734273f41SH. Peter Anvin	bool "Enable support for 16-bit segments" if EXPERT
121834273f41SH. Peter Anvin	default y
1219a5b9e5a2SAndy Lutomirski	depends on MODIFY_LDT_SYSCALL
1220a7f7f624SMasahiro Yamada	help
122134273f41SH. Peter Anvin	  This option is required by programs like Wine to run 16-bit
122234273f41SH. Peter Anvin	  protected mode legacy code on x86 processors.  Disabling
122334273f41SH. Peter Anvin	  this option saves about 300 bytes on i386, or around 6K text
122434273f41SH. Peter Anvin	  plus 16K runtime memory on x86-64,
122534273f41SH. Peter Anvin
122634273f41SH. Peter Anvinconfig X86_ESPFIX32
122734273f41SH. Peter Anvin	def_bool y
122834273f41SH. Peter Anvin	depends on X86_16BIT && X86_32
1229506f1d07SSam Ravnborg
1230197725deSH. Peter Anvinconfig X86_ESPFIX64
1231197725deSH. Peter Anvin	def_bool y
123234273f41SH. Peter Anvin	depends on X86_16BIT && X86_64
1233506f1d07SSam Ravnborg
12341ad83c85SAndy Lutomirskiconfig X86_VSYSCALL_EMULATION
12351ad83c85SAndy Lutomirski	bool "Enable vsyscall emulation" if EXPERT
12361ad83c85SAndy Lutomirski	default y
12371ad83c85SAndy Lutomirski	depends on X86_64
1238a7f7f624SMasahiro Yamada	help
12391ad83c85SAndy Lutomirski	  This enables emulation of the legacy vsyscall page.  Disabling
12401ad83c85SAndy Lutomirski	  it is roughly equivalent to booting with vsyscall=none, except
12411ad83c85SAndy Lutomirski	  that it will also disable the helpful warning if a program
12421ad83c85SAndy Lutomirski	  tries to use a vsyscall.  With this option set to N, offending
12431ad83c85SAndy Lutomirski	  programs will just segfault, citing addresses of the form
12441ad83c85SAndy Lutomirski	  0xffffffffff600?00.
12451ad83c85SAndy Lutomirski
12461ad83c85SAndy Lutomirski	  This option is required by many programs built before 2013, and
12471ad83c85SAndy Lutomirski	  care should be used even with newer programs if set to N.
12481ad83c85SAndy Lutomirski
12491ad83c85SAndy Lutomirski	  Disabling this option saves about 7K of kernel size and
12501ad83c85SAndy Lutomirski	  possibly 4K of additional runtime pagetable memory.
12511ad83c85SAndy Lutomirski
1252111e7b15SThomas Gleixnerconfig X86_IOPL_IOPERM
1253111e7b15SThomas Gleixner	bool "IOPERM and IOPL Emulation"
1254a24ca997SThomas Gleixner	default y
1255a7f7f624SMasahiro Yamada	help
1256111e7b15SThomas Gleixner	  This enables the ioperm() and iopl() syscalls which are necessary
1257111e7b15SThomas Gleixner	  for legacy applications.
1258111e7b15SThomas Gleixner
1259c8137aceSThomas Gleixner	  Legacy IOPL support is an overbroad mechanism which allows user
1260c8137aceSThomas Gleixner	  space aside of accessing all 65536 I/O ports also to disable
1261c8137aceSThomas Gleixner	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1262c8137aceSThomas Gleixner	  capabilities and permission from potentially active security
1263c8137aceSThomas Gleixner	  modules.
1264c8137aceSThomas Gleixner
1265c8137aceSThomas Gleixner	  The emulation restricts the functionality of the syscall to
1266c8137aceSThomas Gleixner	  only allowing the full range I/O port access, but prevents the
1267a24ca997SThomas Gleixner	  ability to disable interrupts from user space which would be
1268a24ca997SThomas Gleixner	  granted if the hardware IOPL mechanism would be used.
1269c8137aceSThomas Gleixner
1270506f1d07SSam Ravnborgconfig TOSHIBA
1271506f1d07SSam Ravnborg	tristate "Toshiba Laptop support"
1272506f1d07SSam Ravnborg	depends on X86_32
1273a7f7f624SMasahiro Yamada	help
1274506f1d07SSam Ravnborg	  This adds a driver to safely access the System Management Mode of
1275506f1d07SSam Ravnborg	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1276506f1d07SSam Ravnborg	  not work on models with a Phoenix BIOS. The System Management Mode
1277506f1d07SSam Ravnborg	  is used to set the BIOS and power saving options on Toshiba portables.
1278506f1d07SSam Ravnborg
1279506f1d07SSam Ravnborg	  For information on utilities to make use of this driver see the
1280506f1d07SSam Ravnborg	  Toshiba Linux utilities web site at:
1281506f1d07SSam Ravnborg	  <http://www.buzzard.org.uk/toshiba/>.
1282506f1d07SSam Ravnborg
1283506f1d07SSam Ravnborg	  Say Y if you intend to run this kernel on a Toshiba portable.
1284506f1d07SSam Ravnborg	  Say N otherwise.
1285506f1d07SSam Ravnborg
1286506f1d07SSam Ravnborgconfig X86_REBOOTFIXUPS
12879ba16087SJan Beulich	bool "Enable X86 board specific fixups for reboot"
12889ba16087SJan Beulich	depends on X86_32
1289a7f7f624SMasahiro Yamada	help
1290506f1d07SSam Ravnborg	  This enables chipset and/or board specific fixups to be done
1291506f1d07SSam Ravnborg	  in order to get reboot to work correctly. This is only needed on
1292506f1d07SSam Ravnborg	  some combinations of hardware and BIOS. The symptom, for which
1293506f1d07SSam Ravnborg	  this config is intended, is when reboot ends with a stalled/hung
1294506f1d07SSam Ravnborg	  system.
1295506f1d07SSam Ravnborg
1296506f1d07SSam Ravnborg	  Currently, the only fixup is for the Geode machines using
12975e3a77e9SFlorian Fainelli	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1298506f1d07SSam Ravnborg
1299506f1d07SSam Ravnborg	  Say Y if you want to enable the fixup. Currently, it's safe to
1300506f1d07SSam Ravnborg	  enable this option even if you don't need it.
1301506f1d07SSam Ravnborg	  Say N otherwise.
1302506f1d07SSam Ravnborg
1303506f1d07SSam Ravnborgconfig MICROCODE
13049a2bc335SBorislav Petkov	bool "CPU microcode loading support"
13059a2bc335SBorislav Petkov	default y
130680030e3dSBorislav Petkov	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1307a7f7f624SMasahiro Yamada	help
1308506f1d07SSam Ravnborg	  If you say Y here, you will be able to update the microcode on
13095f9c01aaSBorislav Petkov	  Intel and AMD processors. The Intel support is for the IA32 family,
13105f9c01aaSBorislav Petkov	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
13115f9c01aaSBorislav Petkov	  AMD support is for families 0x10 and later. You will obviously need
13125f9c01aaSBorislav Petkov	  the actual microcode binary data itself which is not shipped with
13135f9c01aaSBorislav Petkov	  the Linux kernel.
1314506f1d07SSam Ravnborg
13155f9c01aaSBorislav Petkov	  The preferred method to load microcode from a detached initrd is described
1316cb1aaebeSMauro Carvalho Chehab	  in Documentation/x86/microcode.rst. For that you need to enable
13175f9c01aaSBorislav Petkov	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
13185f9c01aaSBorislav Petkov	  initrd for microcode blobs.
1319506f1d07SSam Ravnborg
1320c508c46eSBenjamin Gilbert	  In addition, you can build the microcode into the kernel. For that you
1321c508c46eSBenjamin Gilbert	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1322c508c46eSBenjamin Gilbert	  config option.
1323506f1d07SSam Ravnborg
13248d86f390SPeter Orubaconfig MICROCODE_INTEL
1325e43f6e67SBorislav Petkov	bool "Intel microcode loading support"
13269c55d99eSBorislav Petkov	depends on CPU_SUP_INTEL && MICROCODE
13278d86f390SPeter Oruba	default MICROCODE
1328a7f7f624SMasahiro Yamada	help
13298d86f390SPeter Oruba	  This options enables microcode patch loading support for Intel
13308d86f390SPeter Oruba	  processors.
13318d86f390SPeter Oruba
1332b8989db9SAlan	  For the current Intel microcode data package go to
1333b8989db9SAlan	  <https://downloadcenter.intel.com> and search for
1334b8989db9SAlan	  'Linux Processor Microcode Data File'.
13358d86f390SPeter Oruba
133680cc9f10SPeter Orubaconfig MICROCODE_AMD
1337e43f6e67SBorislav Petkov	bool "AMD microcode loading support"
13389c55d99eSBorislav Petkov	depends on CPU_SUP_AMD && MICROCODE
1339a7f7f624SMasahiro Yamada	help
134080cc9f10SPeter Oruba	  If you select this option, microcode patch loading support for AMD
134180cc9f10SPeter Oruba	  processors will be enabled.
134280cc9f10SPeter Oruba
1343a77a94f8SBorislav Petkovconfig MICROCODE_LATE_LOADING
1344a77a94f8SBorislav Petkov	bool "Late microcode loading (DANGEROUS)"
1345c02f48e0SBorislav Petkov	default n
1346506f1d07SSam Ravnborg	depends on MICROCODE
1347a7f7f624SMasahiro Yamada	help
1348a77a94f8SBorislav Petkov	  Loading microcode late, when the system is up and executing instructions
1349a77a94f8SBorislav Petkov	  is a tricky business and should be avoided if possible. Just the sequence
1350a77a94f8SBorislav Petkov	  of synchronizing all cores and SMT threads is one fragile dance which does
1351a77a94f8SBorislav Petkov	  not guarantee that cores might not softlock after the loading. Therefore,
1352a77a94f8SBorislav Petkov	  use this at your own risk. Late loading taints the kernel too.
1353506f1d07SSam Ravnborg
1354506f1d07SSam Ravnborgconfig X86_MSR
1355506f1d07SSam Ravnborg	tristate "/dev/cpu/*/msr - Model-specific register support"
1356a7f7f624SMasahiro Yamada	help
1357506f1d07SSam Ravnborg	  This device gives privileged processes access to the x86
1358506f1d07SSam Ravnborg	  Model-Specific Registers (MSRs).  It is a character device with
1359506f1d07SSam Ravnborg	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1360506f1d07SSam Ravnborg	  MSR accesses are directed to a specific CPU on multi-processor
1361506f1d07SSam Ravnborg	  systems.
1362506f1d07SSam Ravnborg
1363506f1d07SSam Ravnborgconfig X86_CPUID
1364506f1d07SSam Ravnborg	tristate "/dev/cpu/*/cpuid - CPU information support"
1365a7f7f624SMasahiro Yamada	help
1366506f1d07SSam Ravnborg	  This device gives processes access to the x86 CPUID instruction to
1367506f1d07SSam Ravnborg	  be executed on a specific processor.  It is a character device
1368506f1d07SSam Ravnborg	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1369506f1d07SSam Ravnborg	  /dev/cpu/31/cpuid.
1370506f1d07SSam Ravnborg
1371506f1d07SSam Ravnborgchoice
1372506f1d07SSam Ravnborg	prompt "High Memory Support"
13736fc108a0SJan Beulich	default HIGHMEM4G
1374506f1d07SSam Ravnborg	depends on X86_32
1375506f1d07SSam Ravnborg
1376506f1d07SSam Ravnborgconfig NOHIGHMEM
1377506f1d07SSam Ravnborg	bool "off"
1378a7f7f624SMasahiro Yamada	help
1379506f1d07SSam Ravnborg	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1380506f1d07SSam Ravnborg	  However, the address space of 32-bit x86 processors is only 4
1381506f1d07SSam Ravnborg	  Gigabytes large. That means that, if you have a large amount of
1382506f1d07SSam Ravnborg	  physical memory, not all of it can be "permanently mapped" by the
1383506f1d07SSam Ravnborg	  kernel. The physical memory that's not permanently mapped is called
1384506f1d07SSam Ravnborg	  "high memory".
1385506f1d07SSam Ravnborg
1386506f1d07SSam Ravnborg	  If you are compiling a kernel which will never run on a machine with
1387506f1d07SSam Ravnborg	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1388506f1d07SSam Ravnborg	  choice and suitable for most users). This will result in a "3GB/1GB"
1389506f1d07SSam Ravnborg	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1390506f1d07SSam Ravnborg	  space and the remaining part of the 4GB virtual memory space is used
1391506f1d07SSam Ravnborg	  by the kernel to permanently map as much physical memory as
1392506f1d07SSam Ravnborg	  possible.
1393506f1d07SSam Ravnborg
1394506f1d07SSam Ravnborg	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1395506f1d07SSam Ravnborg	  answer "4GB" here.
1396506f1d07SSam Ravnborg
1397506f1d07SSam Ravnborg	  If more than 4 Gigabytes is used then answer "64GB" here. This
1398506f1d07SSam Ravnborg	  selection turns Intel PAE (Physical Address Extension) mode on.
1399506f1d07SSam Ravnborg	  PAE implements 3-level paging on IA32 processors. PAE is fully
1400506f1d07SSam Ravnborg	  supported by Linux, PAE mode is implemented on all recent Intel
1401506f1d07SSam Ravnborg	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1402506f1d07SSam Ravnborg	  then the kernel will not boot on CPUs that don't support PAE!
1403506f1d07SSam Ravnborg
1404506f1d07SSam Ravnborg	  The actual amount of total physical memory will either be
1405506f1d07SSam Ravnborg	  auto detected or can be forced by using a kernel command line option
1406506f1d07SSam Ravnborg	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1407506f1d07SSam Ravnborg	  your boot loader (lilo or loadlin) about how to pass options to the
1408506f1d07SSam Ravnborg	  kernel at boot time.)
1409506f1d07SSam Ravnborg
1410506f1d07SSam Ravnborg	  If unsure, say "off".
1411506f1d07SSam Ravnborg
1412506f1d07SSam Ravnborgconfig HIGHMEM4G
1413506f1d07SSam Ravnborg	bool "4GB"
1414a7f7f624SMasahiro Yamada	help
1415506f1d07SSam Ravnborg	  Select this if you have a 32-bit processor and between 1 and 4
1416506f1d07SSam Ravnborg	  gigabytes of physical RAM.
1417506f1d07SSam Ravnborg
1418506f1d07SSam Ravnborgconfig HIGHMEM64G
1419506f1d07SSam Ravnborg	bool "64GB"
1420225bac2dSLukas Bulwahn	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1421506f1d07SSam Ravnborg	select X86_PAE
1422a7f7f624SMasahiro Yamada	help
1423506f1d07SSam Ravnborg	  Select this if you have a 32-bit processor and more than 4
1424506f1d07SSam Ravnborg	  gigabytes of physical RAM.
1425506f1d07SSam Ravnborg
1426506f1d07SSam Ravnborgendchoice
1427506f1d07SSam Ravnborg
1428506f1d07SSam Ravnborgchoice
14296a108a14SDavid Rientjes	prompt "Memory split" if EXPERT
1430506f1d07SSam Ravnborg	default VMSPLIT_3G
1431506f1d07SSam Ravnborg	depends on X86_32
1432a7f7f624SMasahiro Yamada	help
1433506f1d07SSam Ravnborg	  Select the desired split between kernel and user memory.
1434506f1d07SSam Ravnborg
1435506f1d07SSam Ravnborg	  If the address range available to the kernel is less than the
1436506f1d07SSam Ravnborg	  physical memory installed, the remaining memory will be available
1437506f1d07SSam Ravnborg	  as "high memory". Accessing high memory is a little more costly
1438506f1d07SSam Ravnborg	  than low memory, as it needs to be mapped into the kernel first.
1439506f1d07SSam Ravnborg	  Note that increasing the kernel address space limits the range
1440506f1d07SSam Ravnborg	  available to user programs, making the address space there
1441506f1d07SSam Ravnborg	  tighter.  Selecting anything other than the default 3G/1G split
1442506f1d07SSam Ravnborg	  will also likely make your kernel incompatible with binary-only
1443506f1d07SSam Ravnborg	  kernel modules.
1444506f1d07SSam Ravnborg
1445506f1d07SSam Ravnborg	  If you are not absolutely sure what you are doing, leave this
1446506f1d07SSam Ravnborg	  option alone!
1447506f1d07SSam Ravnborg
1448506f1d07SSam Ravnborg	config VMSPLIT_3G
1449506f1d07SSam Ravnborg		bool "3G/1G user/kernel split"
1450506f1d07SSam Ravnborg	config VMSPLIT_3G_OPT
1451506f1d07SSam Ravnborg		depends on !X86_PAE
1452506f1d07SSam Ravnborg		bool "3G/1G user/kernel split (for full 1G low memory)"
1453506f1d07SSam Ravnborg	config VMSPLIT_2G
1454506f1d07SSam Ravnborg		bool "2G/2G user/kernel split"
1455506f1d07SSam Ravnborg	config VMSPLIT_2G_OPT
1456506f1d07SSam Ravnborg		depends on !X86_PAE
1457506f1d07SSam Ravnborg		bool "2G/2G user/kernel split (for full 2G low memory)"
1458506f1d07SSam Ravnborg	config VMSPLIT_1G
1459506f1d07SSam Ravnborg		bool "1G/3G user/kernel split"
1460506f1d07SSam Ravnborgendchoice
1461506f1d07SSam Ravnborg
1462506f1d07SSam Ravnborgconfig PAGE_OFFSET
1463506f1d07SSam Ravnborg	hex
1464506f1d07SSam Ravnborg	default 0xB0000000 if VMSPLIT_3G_OPT
1465506f1d07SSam Ravnborg	default 0x80000000 if VMSPLIT_2G
1466506f1d07SSam Ravnborg	default 0x78000000 if VMSPLIT_2G_OPT
1467506f1d07SSam Ravnborg	default 0x40000000 if VMSPLIT_1G
1468506f1d07SSam Ravnborg	default 0xC0000000
1469506f1d07SSam Ravnborg	depends on X86_32
1470506f1d07SSam Ravnborg
1471506f1d07SSam Ravnborgconfig HIGHMEM
14723c2362e6SHarvey Harrison	def_bool y
1473506f1d07SSam Ravnborg	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1474506f1d07SSam Ravnborg
1475506f1d07SSam Ravnborgconfig X86_PAE
14769ba16087SJan Beulich	bool "PAE (Physical Address Extension) Support"
1477506f1d07SSam Ravnborg	depends on X86_32 && !HIGHMEM4G
1478d4a451d5SChristoph Hellwig	select PHYS_ADDR_T_64BIT
14799d99c712SChristian Melki	select SWIOTLB
1480a7f7f624SMasahiro Yamada	help
1481506f1d07SSam Ravnborg	  PAE is required for NX support, and furthermore enables
1482506f1d07SSam Ravnborg	  larger swapspace support for non-overcommit purposes. It
1483506f1d07SSam Ravnborg	  has the cost of more pagetable lookup overhead, and also
1484506f1d07SSam Ravnborg	  consumes more pagetable space per process.
1485506f1d07SSam Ravnborg
148677ef56e4SKirill A. Shutemovconfig X86_5LEVEL
148777ef56e4SKirill A. Shutemov	bool "Enable 5-level page tables support"
148818ec1eafSKirill A. Shutemov	default y
1489eedb92abSKirill A. Shutemov	select DYNAMIC_MEMORY_LAYOUT
1490162434e7SKirill A. Shutemov	select SPARSEMEM_VMEMMAP
149177ef56e4SKirill A. Shutemov	depends on X86_64
1492a7f7f624SMasahiro Yamada	help
149377ef56e4SKirill A. Shutemov	  5-level paging enables access to larger address space:
149477ef56e4SKirill A. Shutemov	  upto 128 PiB of virtual address space and 4 PiB of
149577ef56e4SKirill A. Shutemov	  physical address space.
149677ef56e4SKirill A. Shutemov
149777ef56e4SKirill A. Shutemov	  It will be supported by future Intel CPUs.
149877ef56e4SKirill A. Shutemov
14996657fca0SKirill A. Shutemov	  A kernel with the option enabled can be booted on machines that
15006657fca0SKirill A. Shutemov	  support 4- or 5-level paging.
150177ef56e4SKirill A. Shutemov
1502cb1aaebeSMauro Carvalho Chehab	  See Documentation/x86/x86_64/5level-paging.rst for more
150377ef56e4SKirill A. Shutemov	  information.
150477ef56e4SKirill A. Shutemov
150577ef56e4SKirill A. Shutemov	  Say N if unsure.
150677ef56e4SKirill A. Shutemov
150710971ab2SIngo Molnarconfig X86_DIRECT_GBPAGES
1508e5008abeSLuis R. Rodriguez	def_bool y
15092e1da13fSVlastimil Babka	depends on X86_64
1510a7f7f624SMasahiro Yamada	help
151110971ab2SIngo Molnar	  Certain kernel features effectively disable kernel
151210971ab2SIngo Molnar	  linear 1 GB mappings (even if the CPU otherwise
151310971ab2SIngo Molnar	  supports them), so don't confuse the user by printing
151410971ab2SIngo Molnar	  that we have them enabled.
15159e899816SNick Piggin
15165c280cf6SThomas Gleixnerconfig X86_CPA_STATISTICS
15175c280cf6SThomas Gleixner	bool "Enable statistic for Change Page Attribute"
15185c280cf6SThomas Gleixner	depends on DEBUG_FS
1519a7f7f624SMasahiro Yamada	help
1520b75baaf3SIngo Molnar	  Expose statistics about the Change Page Attribute mechanism, which
1521a943245aSColin Ian King	  helps to determine the effectiveness of preserving large and huge
15225c280cf6SThomas Gleixner	  page mappings when mapping protections are changed.
15235c280cf6SThomas Gleixner
152420f07a04SKirill A. Shutemovconfig X86_MEM_ENCRYPT
152520f07a04SKirill A. Shutemov	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
152620f07a04SKirill A. Shutemov	select DYNAMIC_PHYSICAL_MASK
152720f07a04SKirill A. Shutemov	def_bool n
152820f07a04SKirill A. Shutemov
15297744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT
15307744ccdbSTom Lendacky	bool "AMD Secure Memory Encryption (SME) support"
15317744ccdbSTom Lendacky	depends on X86_64 && CPU_SUP_AMD
153282fef0adSDavid Rientjes	select DMA_COHERENT_POOL
1533ce9084baSArd Biesheuvel	select ARCH_USE_MEMREMAP_PROT
1534597cfe48SJoerg Roedel	select INSTRUCTION_DECODER
1535aa5a4611STom Lendacky	select ARCH_HAS_CC_PLATFORM
153620f07a04SKirill A. Shutemov	select X86_MEM_ENCRYPT
1537a7f7f624SMasahiro Yamada	help
15387744ccdbSTom Lendacky	  Say yes to enable support for the encryption of system memory.
15397744ccdbSTom Lendacky	  This requires an AMD processor that supports Secure Memory
15407744ccdbSTom Lendacky	  Encryption (SME).
15417744ccdbSTom Lendacky
15427744ccdbSTom Lendackyconfig AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
15437744ccdbSTom Lendacky	bool "Activate AMD Secure Memory Encryption (SME) by default"
15447744ccdbSTom Lendacky	depends on AMD_MEM_ENCRYPT
1545a7f7f624SMasahiro Yamada	help
15467744ccdbSTom Lendacky	  Say yes to have system memory encrypted by default if running on
15477744ccdbSTom Lendacky	  an AMD processor that supports Secure Memory Encryption (SME).
15487744ccdbSTom Lendacky
15497744ccdbSTom Lendacky	  If set to Y, then the encryption of system memory can be
15507744ccdbSTom Lendacky	  deactivated with the mem_encrypt=off command line option.
15517744ccdbSTom Lendacky
15527744ccdbSTom Lendacky	  If set to N, then the encryption of system memory can be
15537744ccdbSTom Lendacky	  activated with the mem_encrypt=on command line option.
15547744ccdbSTom Lendacky
1555506f1d07SSam Ravnborg# Common NUMA Features
1556506f1d07SSam Ravnborgconfig NUMA
1557e133f6eaSRandy Dunlap	bool "NUMA Memory Allocation and Scheduler Support"
1558506f1d07SSam Ravnborg	depends on SMP
1559b5660ba7SH. Peter Anvin	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1560b5660ba7SH. Peter Anvin	default y if X86_BIGSMP
15617ecd19cfSKefeng Wang	select USE_PERCPU_NUMA_NODE_ID
1562a7f7f624SMasahiro Yamada	help
1563e133f6eaSRandy Dunlap	  Enable NUMA (Non-Uniform Memory Access) support.
1564fd51b2d7SKOSAKI Motohiro
1565506f1d07SSam Ravnborg	  The kernel will try to allocate memory used by a CPU on the
1566506f1d07SSam Ravnborg	  local memory controller of the CPU and add some more
1567506f1d07SSam Ravnborg	  NUMA awareness to the kernel.
1568506f1d07SSam Ravnborg
1569c280ea5eSIngo Molnar	  For 64-bit this is recommended if the system is Intel Core i7
1570fd51b2d7SKOSAKI Motohiro	  (or later), AMD Opteron, or EM64T NUMA.
1571fd51b2d7SKOSAKI Motohiro
1572b5660ba7SH. Peter Anvin	  For 32-bit this is only needed if you boot a 32-bit
15737cf6c945SDavid Rientjes	  kernel on a 64-bit NUMA platform.
1574fd51b2d7SKOSAKI Motohiro
1575fd51b2d7SKOSAKI Motohiro	  Otherwise, you should say N.
1576506f1d07SSam Ravnborg
1577eec1d4faSHans Rosenfeldconfig AMD_NUMA
15783c2362e6SHarvey Harrison	def_bool y
15793c2362e6SHarvey Harrison	prompt "Old style AMD Opteron NUMA detection"
15805da0ef9aSTejun Heo	depends on X86_64 && NUMA && PCI
1581a7f7f624SMasahiro Yamada	help
1582eec1d4faSHans Rosenfeld	  Enable AMD NUMA node topology detection.  You should say Y here if
1583eec1d4faSHans Rosenfeld	  you have a multi processor AMD system. This uses an old method to
1584eec1d4faSHans Rosenfeld	  read the NUMA configuration directly from the builtin Northbridge
1585eec1d4faSHans Rosenfeld	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1586eec1d4faSHans Rosenfeld	  which also takes priority if both are compiled in.
1587506f1d07SSam Ravnborg
1588506f1d07SSam Ravnborgconfig X86_64_ACPI_NUMA
15893c2362e6SHarvey Harrison	def_bool y
15903c2362e6SHarvey Harrison	prompt "ACPI NUMA detection"
1591506f1d07SSam Ravnborg	depends on X86_64 && NUMA && ACPI && PCI
1592506f1d07SSam Ravnborg	select ACPI_NUMA
1593a7f7f624SMasahiro Yamada	help
1594506f1d07SSam Ravnborg	  Enable ACPI SRAT based node topology detection.
1595506f1d07SSam Ravnborg
1596506f1d07SSam Ravnborgconfig NUMA_EMU
1597506f1d07SSam Ravnborg	bool "NUMA emulation"
15981b7e03efSTejun Heo	depends on NUMA
1599a7f7f624SMasahiro Yamada	help
1600506f1d07SSam Ravnborg	  Enable NUMA emulation. A flat machine will be split
1601506f1d07SSam Ravnborg	  into virtual nodes when booted with "numa=fake=N", where N is the
1602506f1d07SSam Ravnborg	  number of nodes. This is only useful for debugging.
1603506f1d07SSam Ravnborg
1604506f1d07SSam Ravnborgconfig NODES_SHIFT
1605d25e26b6SLinus Torvalds	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
160651591e31SDavid Rientjes	range 1 10
160751591e31SDavid Rientjes	default "10" if MAXSMP
1608506f1d07SSam Ravnborg	default "6" if X86_64
1609506f1d07SSam Ravnborg	default "3"
1610a9ee6cf5SMike Rapoport	depends on NUMA
1611a7f7f624SMasahiro Yamada	help
16121184dc2fSMike Travis	  Specify the maximum number of NUMA Nodes available on the target
1613692105b8SMatt LaPlante	  system.  Increases memory reserved to accommodate various tables.
1614506f1d07SSam Ravnborg
1615506f1d07SSam Ravnborgconfig ARCH_FLATMEM_ENABLE
1616506f1d07SSam Ravnborg	def_bool y
16173b16651fSTejun Heo	depends on X86_32 && !NUMA
1618506f1d07SSam Ravnborg
1619506f1d07SSam Ravnborgconfig ARCH_SPARSEMEM_ENABLE
1620506f1d07SSam Ravnborg	def_bool y
16216ea30386SKees Cook	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1622506f1d07SSam Ravnborg	select SPARSEMEM_STATIC if X86_32
1623506f1d07SSam Ravnborg	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1624506f1d07SSam Ravnborg
16253b16651fSTejun Heoconfig ARCH_SPARSEMEM_DEFAULT
16266ad57f7fSMike Rapoport	def_bool X86_64 || (NUMA && X86_32)
16273b16651fSTejun Heo
1628506f1d07SSam Ravnborgconfig ARCH_SELECT_MEMORY_MODEL
1629506f1d07SSam Ravnborg	def_bool y
16304eda2bc3SDavid Hildenbrand	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1631506f1d07SSam Ravnborg
1632506f1d07SSam Ravnborgconfig ARCH_MEMORY_PROBE
1633a0842b70SToshi Kani	bool "Enable sysfs memory/probe interface"
16345c11f00bSDavid Hildenbrand	depends on MEMORY_HOTPLUG
1635a0842b70SToshi Kani	help
1636a0842b70SToshi Kani	  This option enables a sysfs memory/probe interface for testing.
1637cb1aaebeSMauro Carvalho Chehab	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1638a0842b70SToshi Kani	  If you are unsure how to answer this question, answer N.
1639506f1d07SSam Ravnborg
16403b16651fSTejun Heoconfig ARCH_PROC_KCORE_TEXT
16413b16651fSTejun Heo	def_bool y
16423b16651fSTejun Heo	depends on X86_64 && PROC_KCORE
16433b16651fSTejun Heo
1644a29815a3SAvi Kivityconfig ILLEGAL_POINTER_VALUE
1645a29815a3SAvi Kivity	hex
1646a29815a3SAvi Kivity	default 0 if X86_32
1647a29815a3SAvi Kivity	default 0xdead000000000000 if X86_64
1648a29815a3SAvi Kivity
16497a67832cSDan Williamsconfig X86_PMEM_LEGACY_DEVICE
16507a67832cSDan Williams	bool
16517a67832cSDan Williams
1652ec776ef6SChristoph Hellwigconfig X86_PMEM_LEGACY
16537a67832cSDan Williams	tristate "Support non-standard NVDIMMs and ADR protected memory"
16549f53f9faSDan Williams	depends on PHYS_ADDR_T_64BIT
16559f53f9faSDan Williams	depends on BLK_DEV
16567a67832cSDan Williams	select X86_PMEM_LEGACY_DEVICE
16577b27a862SDan Williams	select NUMA_KEEP_MEMINFO if NUMA
16589f53f9faSDan Williams	select LIBNVDIMM
1659ec776ef6SChristoph Hellwig	help
1660ec776ef6SChristoph Hellwig	  Treat memory marked using the non-standard e820 type of 12 as used
1661ec776ef6SChristoph Hellwig	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1662ec776ef6SChristoph Hellwig	  The kernel will offer these regions to the 'pmem' driver so
1663ec776ef6SChristoph Hellwig	  they can be used for persistent storage.
1664ec776ef6SChristoph Hellwig
1665ec776ef6SChristoph Hellwig	  Say Y if unsure.
1666ec776ef6SChristoph Hellwig
1667506f1d07SSam Ravnborgconfig HIGHPTE
1668506f1d07SSam Ravnborg	bool "Allocate 3rd-level pagetables from highmem"
16696fc108a0SJan Beulich	depends on HIGHMEM
1670a7f7f624SMasahiro Yamada	help
1671506f1d07SSam Ravnborg	  The VM uses one page table entry for each page of physical memory.
1672506f1d07SSam Ravnborg	  For systems with a lot of RAM, this can be wasteful of precious
1673506f1d07SSam Ravnborg	  low memory.  Setting this option will put user-space page table
1674506f1d07SSam Ravnborg	  entries in high memory.
1675506f1d07SSam Ravnborg
16769f077871SJeremy Fitzhardingeconfig X86_CHECK_BIOS_CORRUPTION
16779f077871SJeremy Fitzhardinge	bool "Check for low memory corruption"
1678a7f7f624SMasahiro Yamada	help
16799f077871SJeremy Fitzhardinge	  Periodically check for memory corruption in low memory, which
16809f077871SJeremy Fitzhardinge	  is suspected to be caused by BIOS.  Even when enabled in the
16819f077871SJeremy Fitzhardinge	  configuration, it is disabled at runtime.  Enable it by
16829f077871SJeremy Fitzhardinge	  setting "memory_corruption_check=1" on the kernel command
16839f077871SJeremy Fitzhardinge	  line.  By default it scans the low 64k of memory every 60
16849f077871SJeremy Fitzhardinge	  seconds; see the memory_corruption_check_size and
16859f077871SJeremy Fitzhardinge	  memory_corruption_check_period parameters in
16868c27ceffSMauro Carvalho Chehab	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
16879f077871SJeremy Fitzhardinge
16889f077871SJeremy Fitzhardinge	  When enabled with the default parameters, this option has
16899f077871SJeremy Fitzhardinge	  almost no overhead, as it reserves a relatively small amount
16909f077871SJeremy Fitzhardinge	  of memory and scans it infrequently.  It both detects corruption
16919f077871SJeremy Fitzhardinge	  and prevents it from affecting the running system.
16929f077871SJeremy Fitzhardinge
16939f077871SJeremy Fitzhardinge	  It is, however, intended as a diagnostic tool; if repeatable
16949f077871SJeremy Fitzhardinge	  BIOS-originated corruption always affects the same memory,
16959f077871SJeremy Fitzhardinge	  you can use memmap= to prevent the kernel from using that
16969f077871SJeremy Fitzhardinge	  memory.
16979f077871SJeremy Fitzhardinge
1698c885df50SJeremy Fitzhardingeconfig X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1699c885df50SJeremy Fitzhardinge	bool "Set the default setting of memory_corruption_check"
1700c885df50SJeremy Fitzhardinge	depends on X86_CHECK_BIOS_CORRUPTION
1701c885df50SJeremy Fitzhardinge	default y
1702a7f7f624SMasahiro Yamada	help
1703c885df50SJeremy Fitzhardinge	  Set whether the default state of memory_corruption_check is
1704c885df50SJeremy Fitzhardinge	  on or off.
1705c885df50SJeremy Fitzhardinge
1706506f1d07SSam Ravnborgconfig MATH_EMULATION
1707506f1d07SSam Ravnborg	bool
1708a5b9e5a2SAndy Lutomirski	depends on MODIFY_LDT_SYSCALL
170987d6021bSArnd Bergmann	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1710a7f7f624SMasahiro Yamada	help
1711506f1d07SSam Ravnborg	  Linux can emulate a math coprocessor (used for floating point
1712506f1d07SSam Ravnborg	  operations) if you don't have one. 486DX and Pentium processors have
1713506f1d07SSam Ravnborg	  a math coprocessor built in, 486SX and 386 do not, unless you added
1714506f1d07SSam Ravnborg	  a 487DX or 387, respectively. (The messages during boot time can
1715506f1d07SSam Ravnborg	  give you some hints here ["man dmesg"].) Everyone needs either a
1716506f1d07SSam Ravnborg	  coprocessor or this emulation.
1717506f1d07SSam Ravnborg
1718506f1d07SSam Ravnborg	  If you don't have a math coprocessor, you need to say Y here; if you
1719506f1d07SSam Ravnborg	  say Y here even though you have a coprocessor, the coprocessor will
1720506f1d07SSam Ravnborg	  be used nevertheless. (This behavior can be changed with the kernel
1721506f1d07SSam Ravnborg	  command line option "no387", which comes handy if your coprocessor
1722506f1d07SSam Ravnborg	  is broken. Try "man bootparam" or see the documentation of your boot
1723506f1d07SSam Ravnborg	  loader (lilo or loadlin) about how to pass options to the kernel at
1724506f1d07SSam Ravnborg	  boot time.) This means that it is a good idea to say Y here if you
1725506f1d07SSam Ravnborg	  intend to use this kernel on different machines.
1726506f1d07SSam Ravnborg
1727506f1d07SSam Ravnborg	  More information about the internals of the Linux math coprocessor
1728506f1d07SSam Ravnborg	  emulation can be found in <file:arch/x86/math-emu/README>.
1729506f1d07SSam Ravnborg
1730506f1d07SSam Ravnborg	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1731506f1d07SSam Ravnborg	  kernel, it won't hurt.
1732506f1d07SSam Ravnborg
1733506f1d07SSam Ravnborgconfig MTRR
17346fc108a0SJan Beulich	def_bool y
17356a108a14SDavid Rientjes	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1736a7f7f624SMasahiro Yamada	help
1737506f1d07SSam Ravnborg	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1738506f1d07SSam Ravnborg	  the Memory Type Range Registers (MTRRs) may be used to control
1739506f1d07SSam Ravnborg	  processor access to memory ranges. This is most useful if you have
1740506f1d07SSam Ravnborg	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1741506f1d07SSam Ravnborg	  allows bus write transfers to be combined into a larger transfer
1742506f1d07SSam Ravnborg	  before bursting over the PCI/AGP bus. This can increase performance
1743506f1d07SSam Ravnborg	  of image write operations 2.5 times or more. Saying Y here creates a
1744506f1d07SSam Ravnborg	  /proc/mtrr file which may be used to manipulate your processor's
1745506f1d07SSam Ravnborg	  MTRRs. Typically the X server should use this.
1746506f1d07SSam Ravnborg
1747506f1d07SSam Ravnborg	  This code has a reasonably generic interface so that similar
1748506f1d07SSam Ravnborg	  control registers on other processors can be easily supported
1749506f1d07SSam Ravnborg	  as well:
1750506f1d07SSam Ravnborg
1751506f1d07SSam Ravnborg	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1752506f1d07SSam Ravnborg	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1753506f1d07SSam Ravnborg	  these, the ARRs are used to emulate the MTRRs.
1754506f1d07SSam Ravnborg	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1755506f1d07SSam Ravnborg	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1756506f1d07SSam Ravnborg	  write-combining. All of these processors are supported by this code
1757506f1d07SSam Ravnborg	  and it makes sense to say Y here if you have one of them.
1758506f1d07SSam Ravnborg
1759506f1d07SSam Ravnborg	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1760506f1d07SSam Ravnborg	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1761506f1d07SSam Ravnborg	  can lead to all sorts of problems, so it's good to say Y here.
1762506f1d07SSam Ravnborg
1763506f1d07SSam Ravnborg	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1764506f1d07SSam Ravnborg	  just add about 9 KB to your kernel.
1765506f1d07SSam Ravnborg
1766cb1aaebeSMauro Carvalho Chehab	  See <file:Documentation/x86/mtrr.rst> for more information.
1767506f1d07SSam Ravnborg
176895ffa243SYinghai Luconfig MTRR_SANITIZER
17692ffb3501SYinghai Lu	def_bool y
177095ffa243SYinghai Lu	prompt "MTRR cleanup support"
177195ffa243SYinghai Lu	depends on MTRR
1772a7f7f624SMasahiro Yamada	help
1773aba3728cSThomas Gleixner	  Convert MTRR layout from continuous to discrete, so X drivers can
1774aba3728cSThomas Gleixner	  add writeback entries.
177595ffa243SYinghai Lu
1776aba3728cSThomas Gleixner	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1777692105b8SMatt LaPlante	  The largest mtrr entry size for a continuous block can be set with
1778aba3728cSThomas Gleixner	  mtrr_chunk_size.
177995ffa243SYinghai Lu
17802ffb3501SYinghai Lu	  If unsure, say Y.
178195ffa243SYinghai Lu
178295ffa243SYinghai Luconfig MTRR_SANITIZER_ENABLE_DEFAULT
1783f5098d62SYinghai Lu	int "MTRR cleanup enable value (0-1)"
1784f5098d62SYinghai Lu	range 0 1
1785f5098d62SYinghai Lu	default "0"
178695ffa243SYinghai Lu	depends on MTRR_SANITIZER
1787a7f7f624SMasahiro Yamada	help
1788f5098d62SYinghai Lu	  Enable mtrr cleanup default value
178995ffa243SYinghai Lu
179012031a62SYinghai Luconfig MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
179112031a62SYinghai Lu	int "MTRR cleanup spare reg num (0-7)"
179212031a62SYinghai Lu	range 0 7
179312031a62SYinghai Lu	default "1"
179412031a62SYinghai Lu	depends on MTRR_SANITIZER
1795a7f7f624SMasahiro Yamada	help
179612031a62SYinghai Lu	  mtrr cleanup spare entries default, it can be changed via
1797aba3728cSThomas Gleixner	  mtrr_spare_reg_nr=N on the kernel command line.
179812031a62SYinghai Lu
17992e5d9c85Svenkatesh.pallipadi@intel.comconfig X86_PAT
18006fc108a0SJan Beulich	def_bool y
18016a108a14SDavid Rientjes	prompt "x86 PAT support" if EXPERT
18022a8a2719SIngo Molnar	depends on MTRR
1803a7f7f624SMasahiro Yamada	help
18042e5d9c85Svenkatesh.pallipadi@intel.com	  Use PAT attributes to setup page level cache control.
1805042b78e4SVenki Pallipadi
18062e5d9c85Svenkatesh.pallipadi@intel.com	  PATs are the modern equivalents of MTRRs and are much more
18072e5d9c85Svenkatesh.pallipadi@intel.com	  flexible than MTRRs.
18082e5d9c85Svenkatesh.pallipadi@intel.com
18092e5d9c85Svenkatesh.pallipadi@intel.com	  Say N here if you see bootup problems (boot crash, boot hang,
1810042b78e4SVenki Pallipadi	  spontaneous reboots) or a non-working video driver.
18112e5d9c85Svenkatesh.pallipadi@intel.com
18122e5d9c85Svenkatesh.pallipadi@intel.com	  If unsure, say Y.
18132e5d9c85Svenkatesh.pallipadi@intel.com
181446cf98cdSVenkatesh Pallipadiconfig ARCH_USES_PG_UNCACHED
181546cf98cdSVenkatesh Pallipadi	def_bool y
181646cf98cdSVenkatesh Pallipadi	depends on X86_PAT
181746cf98cdSVenkatesh Pallipadi
1818b971880fSBabu Mogerconfig X86_UMIP
1819796ebc81SRicardo Neri	def_bool y
1820b971880fSBabu Moger	prompt "User Mode Instruction Prevention" if EXPERT
1821a7f7f624SMasahiro Yamada	help
1822b971880fSBabu Moger	  User Mode Instruction Prevention (UMIP) is a security feature in
1823b971880fSBabu Moger	  some x86 processors. If enabled, a general protection fault is
1824b971880fSBabu Moger	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1825b971880fSBabu Moger	  executed in user mode. These instructions unnecessarily expose
1826b971880fSBabu Moger	  information about the hardware state.
1827796ebc81SRicardo Neri
1828796ebc81SRicardo Neri	  The vast majority of applications do not use these instructions.
1829796ebc81SRicardo Neri	  For the very few that do, software emulation is provided in
1830796ebc81SRicardo Neri	  specific cases in protected and virtual-8086 modes. Emulated
1831796ebc81SRicardo Neri	  results are dummy.
1832aa35f896SRicardo Neri
1833156ff4a5SPeter Zijlstraconfig CC_HAS_IBT
1834156ff4a5SPeter Zijlstra	# GCC >= 9 and binutils >= 2.29
1835156ff4a5SPeter Zijlstra	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1836156ff4a5SPeter Zijlstra	# Clang/LLVM >= 14
1837262448f3SNathan Chancellor	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1838262448f3SNathan Chancellor	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1839156ff4a5SPeter Zijlstra	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1840262448f3SNathan Chancellor		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1841156ff4a5SPeter Zijlstra		  $(as-instr,endbr64)
1842156ff4a5SPeter Zijlstra
1843156ff4a5SPeter Zijlstraconfig X86_KERNEL_IBT
1844156ff4a5SPeter Zijlstra	prompt "Indirect Branch Tracking"
1845156ff4a5SPeter Zijlstra	bool
184603f16cd0SJosh Poimboeuf	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1847f6a2c2b2SNathan Chancellor	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1848f6a2c2b2SNathan Chancellor	depends on !LD_IS_LLD || LLD_VERSION >= 140000
184903f16cd0SJosh Poimboeuf	select OBJTOOL
1850156ff4a5SPeter Zijlstra	help
1851156ff4a5SPeter Zijlstra	  Build the kernel with support for Indirect Branch Tracking, a
1852156ff4a5SPeter Zijlstra	  hardware support course-grain forward-edge Control Flow Integrity
1853156ff4a5SPeter Zijlstra	  protection. It enforces that all indirect calls must land on
1854156ff4a5SPeter Zijlstra	  an ENDBR instruction, as such, the compiler will instrument the
1855156ff4a5SPeter Zijlstra	  code with them to make this happen.
1856156ff4a5SPeter Zijlstra
1857ed53a0d9SPeter Zijlstra	  In addition to building the kernel with IBT, seal all functions that
18584cdfc11bSNur Hussein	  are not indirect call targets, avoiding them ever becoming one.
1859ed53a0d9SPeter Zijlstra
1860ed53a0d9SPeter Zijlstra	  This requires LTO like objtool runs and will slow down the build. It
1861ed53a0d9SPeter Zijlstra	  does significantly reduce the number of ENDBR instructions in the
1862ed53a0d9SPeter Zijlstra	  kernel image.
1863ed53a0d9SPeter Zijlstra
186435e97790SDave Hansenconfig X86_INTEL_MEMORY_PROTECTION_KEYS
186538f3e775SBabu Moger	prompt "Memory Protection Keys"
186635e97790SDave Hansen	def_bool y
1867284244a9SDave Hansen	# Note: only available in 64-bit mode
186838f3e775SBabu Moger	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
186952c8e601SIngo Molnar	select ARCH_USES_HIGH_VMA_FLAGS
187052c8e601SIngo Molnar	select ARCH_HAS_PKEYS
1871a7f7f624SMasahiro Yamada	help
1872284244a9SDave Hansen	  Memory Protection Keys provides a mechanism for enforcing
1873284244a9SDave Hansen	  page-based protections, but without requiring modification of the
1874284244a9SDave Hansen	  page tables when an application changes protection domains.
1875284244a9SDave Hansen
18761eecbcdcSMauro Carvalho Chehab	  For details, see Documentation/core-api/protection-keys.rst
1877284244a9SDave Hansen
1878284244a9SDave Hansen	  If unsure, say y.
187935e97790SDave Hansen
1880db616173SMichal Hockochoice
1881db616173SMichal Hocko	prompt "TSX enable mode"
1882db616173SMichal Hocko	depends on CPU_SUP_INTEL
1883db616173SMichal Hocko	default X86_INTEL_TSX_MODE_OFF
1884db616173SMichal Hocko	help
1885db616173SMichal Hocko	  Intel's TSX (Transactional Synchronization Extensions) feature
1886db616173SMichal Hocko	  allows to optimize locking protocols through lock elision which
1887db616173SMichal Hocko	  can lead to a noticeable performance boost.
1888db616173SMichal Hocko
1889db616173SMichal Hocko	  On the other hand it has been shown that TSX can be exploited
1890db616173SMichal Hocko	  to form side channel attacks (e.g. TAA) and chances are there
1891db616173SMichal Hocko	  will be more of those attacks discovered in the future.
1892db616173SMichal Hocko
1893db616173SMichal Hocko	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1894db616173SMichal Hocko	  might override this decision by tsx=on the command line parameter.
1895db616173SMichal Hocko	  Even with TSX enabled, the kernel will attempt to enable the best
1896db616173SMichal Hocko	  possible TAA mitigation setting depending on the microcode available
1897db616173SMichal Hocko	  for the particular machine.
1898db616173SMichal Hocko
1899db616173SMichal Hocko	  This option allows to set the default tsx mode between tsx=on, =off
1900db616173SMichal Hocko	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1901db616173SMichal Hocko	  details.
1902db616173SMichal Hocko
1903db616173SMichal Hocko	  Say off if not sure, auto if TSX is in use but it should be used on safe
1904db616173SMichal Hocko	  platforms or on if TSX is in use and the security aspect of tsx is not
1905db616173SMichal Hocko	  relevant.
1906db616173SMichal Hocko
1907db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_OFF
1908db616173SMichal Hocko	bool "off"
1909db616173SMichal Hocko	help
1910db616173SMichal Hocko	  TSX is disabled if possible - equals to tsx=off command line parameter.
1911db616173SMichal Hocko
1912db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_ON
1913db616173SMichal Hocko	bool "on"
1914db616173SMichal Hocko	help
1915db616173SMichal Hocko	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1916db616173SMichal Hocko	  line parameter.
1917db616173SMichal Hocko
1918db616173SMichal Hockoconfig X86_INTEL_TSX_MODE_AUTO
1919db616173SMichal Hocko	bool "auto"
1920db616173SMichal Hocko	help
1921db616173SMichal Hocko	  TSX is enabled on TSX capable HW that is believed to be safe against
1922db616173SMichal Hocko	  side channel attacks- equals the tsx=auto command line parameter.
1923db616173SMichal Hockoendchoice
1924db616173SMichal Hocko
1925e7e05452SSean Christophersonconfig X86_SGX
1926e7e05452SSean Christopherson	bool "Software Guard eXtensions (SGX)"
1927e7e05452SSean Christopherson	depends on X86_64 && CPU_SUP_INTEL
1928e7e05452SSean Christopherson	depends on CRYPTO=y
1929e7e05452SSean Christopherson	depends on CRYPTO_SHA256=y
1930e7e05452SSean Christopherson	select SRCU
1931e7e05452SSean Christopherson	select MMU_NOTIFIER
1932901ddbb9SJarkko Sakkinen	select NUMA_KEEP_MEMINFO if NUMA
193340e0e784STony Luck	select XARRAY_MULTI
1934e7e05452SSean Christopherson	help
1935e7e05452SSean Christopherson	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1936e7e05452SSean Christopherson	  that can be used by applications to set aside private regions of code
1937e7e05452SSean Christopherson	  and data, referred to as enclaves. An enclave's private memory can
1938e7e05452SSean Christopherson	  only be accessed by code running within the enclave. Accesses from
1939e7e05452SSean Christopherson	  outside the enclave, including other enclaves, are disallowed by
1940e7e05452SSean Christopherson	  hardware.
1941e7e05452SSean Christopherson
1942e7e05452SSean Christopherson	  If unsure, say N.
1943e7e05452SSean Christopherson
1944506f1d07SSam Ravnborgconfig EFI
19459ba16087SJan Beulich	bool "EFI runtime service support"
19465b83683fSHuang, Ying	depends on ACPI
1947f6ce5002SSergey Vlasov	select UCS2_STRING
1948022ee6c5SArd Biesheuvel	select EFI_RUNTIME_WRAPPERS
19491ff2fc02STom Lendacky	select ARCH_USE_MEMREMAP_PROT
1950a7f7f624SMasahiro Yamada	help
19518b2cb7a8SHuang, Ying	  This enables the kernel to use EFI runtime services that are
1952506f1d07SSam Ravnborg	  available (such as the EFI variable services).
1953506f1d07SSam Ravnborg
19548b2cb7a8SHuang, Ying	  This option is only useful on systems that have EFI firmware.
19558b2cb7a8SHuang, Ying	  In addition, you should use the latest ELILO loader available
19568b2cb7a8SHuang, Ying	  at <http://elilo.sourceforge.net> in order to take advantage
19578b2cb7a8SHuang, Ying	  of EFI runtime services. However, even with this option, the
19588b2cb7a8SHuang, Ying	  resultant kernel should continue to boot on existing non-EFI
19598b2cb7a8SHuang, Ying	  platforms.
1960506f1d07SSam Ravnborg
1961291f3632SMatt Flemingconfig EFI_STUB
1962291f3632SMatt Fleming	bool "EFI stub support"
1963c6dbd3e5SPeter Zijlstra	depends on EFI
19648f24f8c2SArd Biesheuvel	depends on $(cc-option,-mabi=ms) || X86_32
19657b2a583aSMatt Fleming	select RELOCATABLE
1966a7f7f624SMasahiro Yamada	help
1967291f3632SMatt Fleming	  This kernel feature allows a bzImage to be loaded directly
1968291f3632SMatt Fleming	  by EFI firmware without the use of a bootloader.
1969291f3632SMatt Fleming
19704f4cfa6cSMauro Carvalho Chehab	  See Documentation/admin-guide/efi-stub.rst for more information.
19710c759662SMatt Fleming
19727d453eeeSMatt Flemingconfig EFI_MIXED
19737d453eeeSMatt Fleming	bool "EFI mixed-mode support"
19747d453eeeSMatt Fleming	depends on EFI_STUB && X86_64
1975a7f7f624SMasahiro Yamada	help
19767d453eeeSMatt Fleming	  Enabling this feature allows a 64-bit kernel to be booted
19777d453eeeSMatt Fleming	  on a 32-bit firmware, provided that your CPU supports 64-bit
19787d453eeeSMatt Fleming	  mode.
19797d453eeeSMatt Fleming
19807d453eeeSMatt Fleming	  Note that it is not possible to boot a mixed-mode enabled
19817d453eeeSMatt Fleming	  kernel via the EFI boot stub - a bootloader that supports
19827d453eeeSMatt Fleming	  the EFI handover protocol must be used.
19837d453eeeSMatt Fleming
19847d453eeeSMatt Fleming	  If unsure, say N.
19857d453eeeSMatt Fleming
19868636a1f9SMasahiro Yamadasource "kernel/Kconfig.hz"
1987506f1d07SSam Ravnborg
1988506f1d07SSam Ravnborgconfig KEXEC
1989506f1d07SSam Ravnborg	bool "kexec system call"
19902965faa5SDave Young	select KEXEC_CORE
1991a7f7f624SMasahiro Yamada	help
1992506f1d07SSam Ravnborg	  kexec is a system call that implements the ability to shutdown your
1993506f1d07SSam Ravnborg	  current kernel, and to start another kernel.  It is like a reboot
1994506f1d07SSam Ravnborg	  but it is independent of the system firmware.   And like a reboot
1995506f1d07SSam Ravnborg	  you can start any kernel with it, not just Linux.
1996506f1d07SSam Ravnborg
1997506f1d07SSam Ravnborg	  The name comes from the similarity to the exec system call.
1998506f1d07SSam Ravnborg
1999506f1d07SSam Ravnborg	  It is an ongoing process to be certain the hardware in a machine
2000506f1d07SSam Ravnborg	  is properly shutdown, so do not be surprised if this code does not
2001bf220695SGeert Uytterhoeven	  initially work for you.  As of this writing the exact hardware
2002bf220695SGeert Uytterhoeven	  interface is strongly in flux, so no good recommendation can be
2003bf220695SGeert Uytterhoeven	  made.
2004506f1d07SSam Ravnborg
200574ca317cSVivek Goyalconfig KEXEC_FILE
200674ca317cSVivek Goyal	bool "kexec file based system call"
20072965faa5SDave Young	select KEXEC_CORE
2008b69a2afdSJonathan McDowell	select HAVE_IMA_KEXEC if IMA
200974ca317cSVivek Goyal	depends on X86_64
201074ca317cSVivek Goyal	depends on CRYPTO=y
201174ca317cSVivek Goyal	depends on CRYPTO_SHA256=y
2012a7f7f624SMasahiro Yamada	help
201374ca317cSVivek Goyal	  This is new version of kexec system call. This system call is
201474ca317cSVivek Goyal	  file based and takes file descriptors as system call argument
201574ca317cSVivek Goyal	  for kernel and initramfs as opposed to list of segments as
201674ca317cSVivek Goyal	  accepted by previous system call.
201774ca317cSVivek Goyal
2018b799a09fSAKASHI Takahiroconfig ARCH_HAS_KEXEC_PURGATORY
2019b799a09fSAKASHI Takahiro	def_bool KEXEC_FILE
2020b799a09fSAKASHI Takahiro
202199d5cadfSJiri Bohacconfig KEXEC_SIG
20228e7d8381SVivek Goyal	bool "Verify kernel signature during kexec_file_load() syscall"
202374ca317cSVivek Goyal	depends on KEXEC_FILE
2024a7f7f624SMasahiro Yamada	help
202599d5cadfSJiri Bohac
202699d5cadfSJiri Bohac	  This option makes the kexec_file_load() syscall check for a valid
202799d5cadfSJiri Bohac	  signature of the kernel image.  The image can still be loaded without
202899d5cadfSJiri Bohac	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
202999d5cadfSJiri Bohac	  there's a signature that we can check, then it must be valid.
203099d5cadfSJiri Bohac
203199d5cadfSJiri Bohac	  In addition to this option, you need to enable signature
203299d5cadfSJiri Bohac	  verification for the corresponding kernel image type being
203399d5cadfSJiri Bohac	  loaded in order for this to work.
203499d5cadfSJiri Bohac
203599d5cadfSJiri Bohacconfig KEXEC_SIG_FORCE
203699d5cadfSJiri Bohac	bool "Require a valid signature in kexec_file_load() syscall"
203799d5cadfSJiri Bohac	depends on KEXEC_SIG
2038a7f7f624SMasahiro Yamada	help
20398e7d8381SVivek Goyal	  This option makes kernel signature verification mandatory for
2040d8eb8940SBorislav Petkov	  the kexec_file_load() syscall.
20418e7d8381SVivek Goyal
20428e7d8381SVivek Goyalconfig KEXEC_BZIMAGE_VERIFY_SIG
20438e7d8381SVivek Goyal	bool "Enable bzImage signature verification support"
204499d5cadfSJiri Bohac	depends on KEXEC_SIG
20458e7d8381SVivek Goyal	depends on SIGNED_PE_FILE_VERIFICATION
20468e7d8381SVivek Goyal	select SYSTEM_TRUSTED_KEYRING
2047a7f7f624SMasahiro Yamada	help
20488e7d8381SVivek Goyal	  Enable bzImage signature verification support.
20498e7d8381SVivek Goyal
2050506f1d07SSam Ravnborgconfig CRASH_DUMP
205104b69447SPavel Machek	bool "kernel crash dumps"
2052506f1d07SSam Ravnborg	depends on X86_64 || (X86_32 && HIGHMEM)
2053a7f7f624SMasahiro Yamada	help
2054506f1d07SSam Ravnborg	  Generate crash dump after being started by kexec.
2055506f1d07SSam Ravnborg	  This should be normally only set in special crash dump kernels
2056506f1d07SSam Ravnborg	  which are loaded in the main kernel with kexec-tools into
2057506f1d07SSam Ravnborg	  a specially reserved region and then later executed after
2058506f1d07SSam Ravnborg	  a crash by kdump/kexec. The crash dump kernel must be compiled
2059506f1d07SSam Ravnborg	  to a memory address not used by the main kernel or BIOS using
2060506f1d07SSam Ravnborg	  PHYSICAL_START, or it must be built as a relocatable image
2061506f1d07SSam Ravnborg	  (CONFIG_RELOCATABLE=y).
2062330d4810SMauro Carvalho Chehab	  For more details see Documentation/admin-guide/kdump/kdump.rst
2063506f1d07SSam Ravnborg
20643ab83521SHuang Yingconfig KEXEC_JUMP
20656ea30386SKees Cook	bool "kexec jump"
2066fee7b0d8SHuang Ying	depends on KEXEC && HIBERNATION
2067a7f7f624SMasahiro Yamada	help
206889081d17SHuang Ying	  Jump between original kernel and kexeced kernel and invoke
206989081d17SHuang Ying	  code in physical address mode via KEXEC
20703ab83521SHuang Ying
2071506f1d07SSam Ravnborgconfig PHYSICAL_START
20726a108a14SDavid Rientjes	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2073ceefccc9SH. Peter Anvin	default "0x1000000"
2074a7f7f624SMasahiro Yamada	help
2075506f1d07SSam Ravnborg	  This gives the physical address where the kernel is loaded.
2076506f1d07SSam Ravnborg
2077506f1d07SSam Ravnborg	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2078506f1d07SSam Ravnborg	  bzImage will decompress itself to above physical address and
2079506f1d07SSam Ravnborg	  run from there. Otherwise, bzImage will run from the address where
2080506f1d07SSam Ravnborg	  it has been loaded by the boot loader and will ignore above physical
2081506f1d07SSam Ravnborg	  address.
2082506f1d07SSam Ravnborg
2083506f1d07SSam Ravnborg	  In normal kdump cases one does not have to set/change this option
2084506f1d07SSam Ravnborg	  as now bzImage can be compiled as a completely relocatable image
2085506f1d07SSam Ravnborg	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2086506f1d07SSam Ravnborg	  address. This option is mainly useful for the folks who don't want
2087506f1d07SSam Ravnborg	  to use a bzImage for capturing the crash dump and want to use a
2088506f1d07SSam Ravnborg	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2089506f1d07SSam Ravnborg	  to be specifically compiled to run from a specific memory area
2090506f1d07SSam Ravnborg	  (normally a reserved region) and this option comes handy.
2091506f1d07SSam Ravnborg
2092ceefccc9SH. Peter Anvin	  So if you are using bzImage for capturing the crash dump,
2093ceefccc9SH. Peter Anvin	  leave the value here unchanged to 0x1000000 and set
2094ceefccc9SH. Peter Anvin	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2095ceefccc9SH. Peter Anvin	  for capturing the crash dump change this value to start of
2096ceefccc9SH. Peter Anvin	  the reserved region.  In other words, it can be set based on
2097ceefccc9SH. Peter Anvin	  the "X" value as specified in the "crashkernel=YM@XM"
2098ceefccc9SH. Peter Anvin	  command line boot parameter passed to the panic-ed
2099330d4810SMauro Carvalho Chehab	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2100ceefccc9SH. Peter Anvin	  for more details about crash dumps.
2101506f1d07SSam Ravnborg
2102506f1d07SSam Ravnborg	  Usage of bzImage for capturing the crash dump is recommended as
2103506f1d07SSam Ravnborg	  one does not have to build two kernels. Same kernel can be used
2104506f1d07SSam Ravnborg	  as production kernel and capture kernel. Above option should have
2105506f1d07SSam Ravnborg	  gone away after relocatable bzImage support is introduced. But it
2106506f1d07SSam Ravnborg	  is present because there are users out there who continue to use
2107506f1d07SSam Ravnborg	  vmlinux for dump capture. This option should go away down the
2108506f1d07SSam Ravnborg	  line.
2109506f1d07SSam Ravnborg
2110506f1d07SSam Ravnborg	  Don't change this unless you know what you are doing.
2111506f1d07SSam Ravnborg
2112506f1d07SSam Ravnborgconfig RELOCATABLE
211326717808SH. Peter Anvin	bool "Build a relocatable kernel"
211426717808SH. Peter Anvin	default y
2115a7f7f624SMasahiro Yamada	help
2116506f1d07SSam Ravnborg	  This builds a kernel image that retains relocation information
2117506f1d07SSam Ravnborg	  so it can be loaded someplace besides the default 1MB.
2118506f1d07SSam Ravnborg	  The relocations tend to make the kernel binary about 10% larger,
2119506f1d07SSam Ravnborg	  but are discarded at runtime.
2120506f1d07SSam Ravnborg
2121506f1d07SSam Ravnborg	  One use is for the kexec on panic case where the recovery kernel
2122506f1d07SSam Ravnborg	  must live at a different physical address than the primary
2123506f1d07SSam Ravnborg	  kernel.
2124506f1d07SSam Ravnborg
2125506f1d07SSam Ravnborg	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2126506f1d07SSam Ravnborg	  it has been loaded at and the compile time physical address
21278ab3820fSKees Cook	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2128506f1d07SSam Ravnborg
21298ab3820fSKees Cookconfig RANDOMIZE_BASE
2130e8581e3dSBaoquan He	bool "Randomize the address of the kernel image (KASLR)"
21318ab3820fSKees Cook	depends on RELOCATABLE
21326807c846SIngo Molnar	default y
2133a7f7f624SMasahiro Yamada	help
2134e8581e3dSBaoquan He	  In support of Kernel Address Space Layout Randomization (KASLR),
2135e8581e3dSBaoquan He	  this randomizes the physical address at which the kernel image
2136e8581e3dSBaoquan He	  is decompressed and the virtual address where the kernel
2137e8581e3dSBaoquan He	  image is mapped, as a security feature that deters exploit
2138e8581e3dSBaoquan He	  attempts relying on knowledge of the location of kernel
2139e8581e3dSBaoquan He	  code internals.
2140e8581e3dSBaoquan He
2141ed9f007eSKees Cook	  On 64-bit, the kernel physical and virtual addresses are
2142ed9f007eSKees Cook	  randomized separately. The physical address will be anywhere
2143ed9f007eSKees Cook	  between 16MB and the top of physical memory (up to 64TB). The
2144ed9f007eSKees Cook	  virtual address will be randomized from 16MB up to 1GB (9 bits
2145ed9f007eSKees Cook	  of entropy). Note that this also reduces the memory space
2146ed9f007eSKees Cook	  available to kernel modules from 1.5GB to 1GB.
2147ed9f007eSKees Cook
2148ed9f007eSKees Cook	  On 32-bit, the kernel physical and virtual addresses are
2149ed9f007eSKees Cook	  randomized together. They will be randomized from 16MB up to
2150ed9f007eSKees Cook	  512MB (8 bits of entropy).
21518ab3820fSKees Cook
2152a653f356SKees Cook	  Entropy is generated using the RDRAND instruction if it is
2153e8581e3dSBaoquan He	  supported. If RDTSC is supported, its value is mixed into
2154e8581e3dSBaoquan He	  the entropy pool as well. If neither RDRAND nor RDTSC are
2155ed9f007eSKees Cook	  supported, then entropy is read from the i8254 timer. The
2156ed9f007eSKees Cook	  usable entropy is limited by the kernel being built using
2157ed9f007eSKees Cook	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2158ed9f007eSKees Cook	  minimum of 2MB. As a result, only 10 bits of entropy are
2159ed9f007eSKees Cook	  theoretically possible, but the implementations are further
2160ed9f007eSKees Cook	  limited due to memory layouts.
2161e8581e3dSBaoquan He
21626807c846SIngo Molnar	  If unsure, say Y.
2163da2b6fb9SKees Cook
21648ab3820fSKees Cook# Relocation on x86 needs some additional build support
2165845adf72SH. Peter Anvinconfig X86_NEED_RELOCS
2166845adf72SH. Peter Anvin	def_bool y
21678ab3820fSKees Cook	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2168845adf72SH. Peter Anvin
2169506f1d07SSam Ravnborgconfig PHYSICAL_ALIGN
2170a0215061SKees Cook	hex "Alignment value to which kernel should be aligned"
21718ab3820fSKees Cook	default "0x200000"
2172a0215061SKees Cook	range 0x2000 0x1000000 if X86_32
2173a0215061SKees Cook	range 0x200000 0x1000000 if X86_64
2174a7f7f624SMasahiro Yamada	help
2175506f1d07SSam Ravnborg	  This value puts the alignment restrictions on physical address
2176506f1d07SSam Ravnborg	  where kernel is loaded and run from. Kernel is compiled for an
2177506f1d07SSam Ravnborg	  address which meets above alignment restriction.
2178506f1d07SSam Ravnborg
2179506f1d07SSam Ravnborg	  If bootloader loads the kernel at a non-aligned address and
2180506f1d07SSam Ravnborg	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2181506f1d07SSam Ravnborg	  address aligned to above value and run from there.
2182506f1d07SSam Ravnborg
2183506f1d07SSam Ravnborg	  If bootloader loads the kernel at a non-aligned address and
2184506f1d07SSam Ravnborg	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2185506f1d07SSam Ravnborg	  load address and decompress itself to the address it has been
2186506f1d07SSam Ravnborg	  compiled for and run from there. The address for which kernel is
2187506f1d07SSam Ravnborg	  compiled already meets above alignment restrictions. Hence the
2188506f1d07SSam Ravnborg	  end result is that kernel runs from a physical address meeting
2189506f1d07SSam Ravnborg	  above alignment restrictions.
2190506f1d07SSam Ravnborg
2191a0215061SKees Cook	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2192a0215061SKees Cook	  this value must be a multiple of 0x200000.
2193a0215061SKees Cook
2194506f1d07SSam Ravnborg	  Don't change this unless you know what you are doing.
2195506f1d07SSam Ravnborg
2196eedb92abSKirill A. Shutemovconfig DYNAMIC_MEMORY_LAYOUT
2197eedb92abSKirill A. Shutemov	bool
2198a7f7f624SMasahiro Yamada	help
2199eedb92abSKirill A. Shutemov	  This option makes base addresses of vmalloc and vmemmap as well as
2200eedb92abSKirill A. Shutemov	  __PAGE_OFFSET movable during boot.
2201eedb92abSKirill A. Shutemov
22020483e1faSThomas Garnierconfig RANDOMIZE_MEMORY
22030483e1faSThomas Garnier	bool "Randomize the kernel memory sections"
22040483e1faSThomas Garnier	depends on X86_64
22050483e1faSThomas Garnier	depends on RANDOMIZE_BASE
2206eedb92abSKirill A. Shutemov	select DYNAMIC_MEMORY_LAYOUT
22070483e1faSThomas Garnier	default RANDOMIZE_BASE
2208a7f7f624SMasahiro Yamada	help
22090483e1faSThomas Garnier	  Randomizes the base virtual address of kernel memory sections
22100483e1faSThomas Garnier	  (physical memory mapping, vmalloc & vmemmap). This security feature
22110483e1faSThomas Garnier	  makes exploits relying on predictable memory locations less reliable.
22120483e1faSThomas Garnier
22130483e1faSThomas Garnier	  The order of allocations remains unchanged. Entropy is generated in
22140483e1faSThomas Garnier	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
22150483e1faSThomas Garnier	  configuration have in average 30,000 different possible virtual
22160483e1faSThomas Garnier	  addresses for each memory section.
22170483e1faSThomas Garnier
22186807c846SIngo Molnar	  If unsure, say Y.
22190483e1faSThomas Garnier
222090397a41SThomas Garnierconfig RANDOMIZE_MEMORY_PHYSICAL_PADDING
222190397a41SThomas Garnier	hex "Physical memory mapping padding" if EXPERT
222290397a41SThomas Garnier	depends on RANDOMIZE_MEMORY
222390397a41SThomas Garnier	default "0xa" if MEMORY_HOTPLUG
222490397a41SThomas Garnier	default "0x0"
222590397a41SThomas Garnier	range 0x1 0x40 if MEMORY_HOTPLUG
222690397a41SThomas Garnier	range 0x0 0x40
2227a7f7f624SMasahiro Yamada	help
222890397a41SThomas Garnier	  Define the padding in terabytes added to the existing physical
222990397a41SThomas Garnier	  memory size during kernel memory randomization. It is useful
223090397a41SThomas Garnier	  for memory hotplug support but reduces the entropy available for
223190397a41SThomas Garnier	  address randomization.
223290397a41SThomas Garnier
223390397a41SThomas Garnier	  If unsure, leave at the default value.
223490397a41SThomas Garnier
2235506f1d07SSam Ravnborgconfig HOTPLUG_CPU
2236bebd024eSThomas Gleixner	def_bool y
223740b31360SStephen Rothwell	depends on SMP
2238506f1d07SSam Ravnborg
223980aa1dffSFenghua Yuconfig BOOTPARAM_HOTPLUG_CPU0
224080aa1dffSFenghua Yu	bool "Set default setting of cpu0_hotpluggable"
22412c922cd0SKees Cook	depends on HOTPLUG_CPU
2242a7f7f624SMasahiro Yamada	help
224380aa1dffSFenghua Yu	  Set whether default state of cpu0_hotpluggable is on or off.
224480aa1dffSFenghua Yu
224580aa1dffSFenghua Yu	  Say Y here to enable CPU0 hotplug by default. If this switch
224680aa1dffSFenghua Yu	  is turned on, there is no need to give cpu0_hotplug kernel
224780aa1dffSFenghua Yu	  parameter and the CPU0 hotplug feature is enabled by default.
224880aa1dffSFenghua Yu
224980aa1dffSFenghua Yu	  Please note: there are two known CPU0 dependencies if you want
225080aa1dffSFenghua Yu	  to enable the CPU0 hotplug feature either by this switch or by
225180aa1dffSFenghua Yu	  cpu0_hotplug kernel parameter.
225280aa1dffSFenghua Yu
225380aa1dffSFenghua Yu	  First, resume from hibernate or suspend always starts from CPU0.
225480aa1dffSFenghua Yu	  So hibernate and suspend are prevented if CPU0 is offline.
225580aa1dffSFenghua Yu
225680aa1dffSFenghua Yu	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
225780aa1dffSFenghua Yu	  offline if any interrupt can not migrate out of CPU0. There may
225880aa1dffSFenghua Yu	  be other CPU0 dependencies.
225980aa1dffSFenghua Yu
226080aa1dffSFenghua Yu	  Please make sure the dependencies are under your control before
226180aa1dffSFenghua Yu	  you enable this feature.
226280aa1dffSFenghua Yu
226380aa1dffSFenghua Yu	  Say N if you don't want to enable CPU0 hotplug feature by default.
226480aa1dffSFenghua Yu	  You still can enable the CPU0 hotplug feature at boot by kernel
226580aa1dffSFenghua Yu	  parameter cpu0_hotplug.
226680aa1dffSFenghua Yu
2267a71c8bc5SFenghua Yuconfig DEBUG_HOTPLUG_CPU0
2268a71c8bc5SFenghua Yu	def_bool n
2269a71c8bc5SFenghua Yu	prompt "Debug CPU0 hotplug"
22702c922cd0SKees Cook	depends on HOTPLUG_CPU
2271a7f7f624SMasahiro Yamada	help
2272a71c8bc5SFenghua Yu	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2273a71c8bc5SFenghua Yu	  soon as possible and boots up userspace with CPU0 offlined. User
2274a71c8bc5SFenghua Yu	  can online CPU0 back after boot time.
2275a71c8bc5SFenghua Yu
2276a71c8bc5SFenghua Yu	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2277a71c8bc5SFenghua Yu	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2278a71c8bc5SFenghua Yu	  compilation or giving cpu0_hotplug kernel parameter at boot.
2279a71c8bc5SFenghua Yu
2280a71c8bc5SFenghua Yu	  If unsure, say N.
2281a71c8bc5SFenghua Yu
2282506f1d07SSam Ravnborgconfig COMPAT_VDSO
2283b0b49f26SAndy Lutomirski	def_bool n
2284b0b49f26SAndy Lutomirski	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2285953fee1dSIngo Molnar	depends on COMPAT_32
2286a7f7f624SMasahiro Yamada	help
2287b0b49f26SAndy Lutomirski	  Certain buggy versions of glibc will crash if they are
2288b0b49f26SAndy Lutomirski	  presented with a 32-bit vDSO that is not mapped at the address
2289b0b49f26SAndy Lutomirski	  indicated in its segment table.
2290e84446deSRandy Dunlap
2291b0b49f26SAndy Lutomirski	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2292b0b49f26SAndy Lutomirski	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2293b0b49f26SAndy Lutomirski	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2294b0b49f26SAndy Lutomirski	  the only released version with the bug, but OpenSUSE 9
2295b0b49f26SAndy Lutomirski	  contains a buggy "glibc 2.3.2".
2296506f1d07SSam Ravnborg
2297b0b49f26SAndy Lutomirski	  The symptom of the bug is that everything crashes on startup, saying:
2298b0b49f26SAndy Lutomirski	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2299b0b49f26SAndy Lutomirski
2300b0b49f26SAndy Lutomirski	  Saying Y here changes the default value of the vdso32 boot
2301b0b49f26SAndy Lutomirski	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2302b0b49f26SAndy Lutomirski	  This works around the glibc bug but hurts performance.
2303b0b49f26SAndy Lutomirski
2304b0b49f26SAndy Lutomirski	  If unsure, say N: if you are compiling your own kernel, you
2305b0b49f26SAndy Lutomirski	  are unlikely to be using a buggy version of glibc.
2306506f1d07SSam Ravnborg
23073dc33bd3SKees Cookchoice
23083dc33bd3SKees Cook	prompt "vsyscall table for legacy applications"
23093dc33bd3SKees Cook	depends on X86_64
2310625b7b7fSAndy Lutomirski	default LEGACY_VSYSCALL_XONLY
23113dc33bd3SKees Cook	help
23123dc33bd3SKees Cook	  Legacy user code that does not know how to find the vDSO expects
23133dc33bd3SKees Cook	  to be able to issue three syscalls by calling fixed addresses in
23143dc33bd3SKees Cook	  kernel space. Since this location is not randomized with ASLR,
23153dc33bd3SKees Cook	  it can be used to assist security vulnerability exploitation.
23163dc33bd3SKees Cook
23173dc33bd3SKees Cook	  This setting can be changed at boot time via the kernel command
2318bf00745eSAndy Lutomirski	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2319bf00745eSAndy Lutomirski	  is deprecated and can only be enabled using the kernel command
2320bf00745eSAndy Lutomirski	  line.
23213dc33bd3SKees Cook
23223dc33bd3SKees Cook	  On a system with recent enough glibc (2.14 or newer) and no
23233dc33bd3SKees Cook	  static binaries, you can say None without a performance penalty
23243dc33bd3SKees Cook	  to improve security.
23253dc33bd3SKees Cook
2326bd49e16eSAndy Lutomirski	  If unsure, select "Emulate execution only".
23273dc33bd3SKees Cook
2328bd49e16eSAndy Lutomirski	config LEGACY_VSYSCALL_XONLY
2329bd49e16eSAndy Lutomirski		bool "Emulate execution only"
2330bd49e16eSAndy Lutomirski		help
2331bd49e16eSAndy Lutomirski		  The kernel traps and emulates calls into the fixed vsyscall
2332bd49e16eSAndy Lutomirski		  address mapping and does not allow reads.  This
2333bd49e16eSAndy Lutomirski		  configuration is recommended when userspace might use the
2334bd49e16eSAndy Lutomirski		  legacy vsyscall area but support for legacy binary
2335bd49e16eSAndy Lutomirski		  instrumentation of legacy code is not needed.  It mitigates
2336bd49e16eSAndy Lutomirski		  certain uses of the vsyscall area as an ASLR-bypassing
2337bd49e16eSAndy Lutomirski		  buffer.
23383dc33bd3SKees Cook
23393dc33bd3SKees Cook	config LEGACY_VSYSCALL_NONE
23403dc33bd3SKees Cook		bool "None"
23413dc33bd3SKees Cook		help
23423dc33bd3SKees Cook		  There will be no vsyscall mapping at all. This will
23433dc33bd3SKees Cook		  eliminate any risk of ASLR bypass due to the vsyscall
23443dc33bd3SKees Cook		  fixed address mapping. Attempts to use the vsyscalls
23453dc33bd3SKees Cook		  will be reported to dmesg, so that either old or
23463dc33bd3SKees Cook		  malicious userspace programs can be identified.
23473dc33bd3SKees Cook
23483dc33bd3SKees Cookendchoice
23493dc33bd3SKees Cook
2350516cbf37STim Birdconfig CMDLINE_BOOL
2351516cbf37STim Bird	bool "Built-in kernel command line"
2352a7f7f624SMasahiro Yamada	help
2353516cbf37STim Bird	  Allow for specifying boot arguments to the kernel at
2354516cbf37STim Bird	  build time.  On some systems (e.g. embedded ones), it is
2355516cbf37STim Bird	  necessary or convenient to provide some or all of the
2356516cbf37STim Bird	  kernel boot arguments with the kernel itself (that is,
2357516cbf37STim Bird	  to not rely on the boot loader to provide them.)
2358516cbf37STim Bird
2359516cbf37STim Bird	  To compile command line arguments into the kernel,
2360516cbf37STim Bird	  set this option to 'Y', then fill in the
236169711ca1SSébastien Hinderer	  boot arguments in CONFIG_CMDLINE.
2362516cbf37STim Bird
2363516cbf37STim Bird	  Systems with fully functional boot loaders (i.e. non-embedded)
2364516cbf37STim Bird	  should leave this option set to 'N'.
2365516cbf37STim Bird
2366516cbf37STim Birdconfig CMDLINE
2367516cbf37STim Bird	string "Built-in kernel command string"
2368516cbf37STim Bird	depends on CMDLINE_BOOL
2369516cbf37STim Bird	default ""
2370a7f7f624SMasahiro Yamada	help
2371516cbf37STim Bird	  Enter arguments here that should be compiled into the kernel
2372516cbf37STim Bird	  image and used at boot time.  If the boot loader provides a
2373516cbf37STim Bird	  command line at boot time, it is appended to this string to
2374516cbf37STim Bird	  form the full kernel command line, when the system boots.
2375516cbf37STim Bird
2376516cbf37STim Bird	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2377516cbf37STim Bird	  change this behavior.
2378516cbf37STim Bird
2379516cbf37STim Bird	  In most cases, the command line (whether built-in or provided
2380516cbf37STim Bird	  by the boot loader) should specify the device for the root
2381516cbf37STim Bird	  file system.
2382516cbf37STim Bird
2383516cbf37STim Birdconfig CMDLINE_OVERRIDE
2384516cbf37STim Bird	bool "Built-in command line overrides boot loader arguments"
2385645e6466SAnders Roxell	depends on CMDLINE_BOOL && CMDLINE != ""
2386a7f7f624SMasahiro Yamada	help
2387516cbf37STim Bird	  Set this option to 'Y' to have the kernel ignore the boot loader
2388516cbf37STim Bird	  command line, and use ONLY the built-in command line.
2389516cbf37STim Bird
2390516cbf37STim Bird	  This is used to work around broken boot loaders.  This should
2391516cbf37STim Bird	  be set to 'N' under normal conditions.
2392516cbf37STim Bird
2393a5b9e5a2SAndy Lutomirskiconfig MODIFY_LDT_SYSCALL
2394a5b9e5a2SAndy Lutomirski	bool "Enable the LDT (local descriptor table)" if EXPERT
2395a5b9e5a2SAndy Lutomirski	default y
2396a7f7f624SMasahiro Yamada	help
2397a5b9e5a2SAndy Lutomirski	  Linux can allow user programs to install a per-process x86
2398a5b9e5a2SAndy Lutomirski	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2399a5b9e5a2SAndy Lutomirski	  call.  This is required to run 16-bit or segmented code such as
2400a5b9e5a2SAndy Lutomirski	  DOSEMU or some Wine programs.  It is also used by some very old
2401a5b9e5a2SAndy Lutomirski	  threading libraries.
2402a5b9e5a2SAndy Lutomirski
2403a5b9e5a2SAndy Lutomirski	  Enabling this feature adds a small amount of overhead to
2404a5b9e5a2SAndy Lutomirski	  context switches and increases the low-level kernel attack
2405a5b9e5a2SAndy Lutomirski	  surface.  Disabling it removes the modify_ldt(2) system call.
2406a5b9e5a2SAndy Lutomirski
2407a5b9e5a2SAndy Lutomirski	  Saying 'N' here may make sense for embedded or server kernels.
2408a5b9e5a2SAndy Lutomirski
24093aac3ebeSThomas Gleixnerconfig STRICT_SIGALTSTACK_SIZE
24103aac3ebeSThomas Gleixner	bool "Enforce strict size checking for sigaltstack"
24113aac3ebeSThomas Gleixner	depends on DYNAMIC_SIGFRAME
24123aac3ebeSThomas Gleixner	help
24133aac3ebeSThomas Gleixner	  For historical reasons MINSIGSTKSZ is a constant which became
24143aac3ebeSThomas Gleixner	  already too small with AVX512 support. Add a mechanism to
24153aac3ebeSThomas Gleixner	  enforce strict checking of the sigaltstack size against the
24163aac3ebeSThomas Gleixner	  real size of the FPU frame. This option enables the check
24173aac3ebeSThomas Gleixner	  by default. It can also be controlled via the kernel command
24183aac3ebeSThomas Gleixner	  line option 'strict_sas_size' independent of this config
24193aac3ebeSThomas Gleixner	  switch. Enabling it might break existing applications which
24203aac3ebeSThomas Gleixner	  allocate a too small sigaltstack but 'work' because they
24213aac3ebeSThomas Gleixner	  never get a signal delivered.
24223aac3ebeSThomas Gleixner
24233aac3ebeSThomas Gleixner	  Say 'N' unless you want to really enforce this check.
24243aac3ebeSThomas Gleixner
2425b700e7f0SSeth Jenningssource "kernel/livepatch/Kconfig"
2426b700e7f0SSeth Jennings
2427506f1d07SSam Ravnborgendmenu
2428506f1d07SSam Ravnborg
2429f43b9876SPeter Zijlstraconfig CC_HAS_SLS
2430f43b9876SPeter Zijlstra	def_bool $(cc-option,-mharden-sls=all)
2431f43b9876SPeter Zijlstra
2432f43b9876SPeter Zijlstraconfig CC_HAS_RETURN_THUNK
2433f43b9876SPeter Zijlstra	def_bool $(cc-option,-mfunction-return=thunk-extern)
2434f43b9876SPeter Zijlstra
2435f43b9876SPeter Zijlstramenuconfig SPECULATION_MITIGATIONS
2436f43b9876SPeter Zijlstra	bool "Mitigations for speculative execution vulnerabilities"
2437f43b9876SPeter Zijlstra	default y
2438f43b9876SPeter Zijlstra	help
2439f43b9876SPeter Zijlstra	  Say Y here to enable options which enable mitigations for
2440f43b9876SPeter Zijlstra	  speculative execution hardware vulnerabilities.
2441f43b9876SPeter Zijlstra
2442f43b9876SPeter Zijlstra	  If you say N, all mitigations will be disabled. You really
2443f43b9876SPeter Zijlstra	  should know what you are doing to say so.
2444f43b9876SPeter Zijlstra
2445f43b9876SPeter Zijlstraif SPECULATION_MITIGATIONS
2446f43b9876SPeter Zijlstra
2447f43b9876SPeter Zijlstraconfig PAGE_TABLE_ISOLATION
2448f43b9876SPeter Zijlstra	bool "Remove the kernel mapping in user mode"
2449f43b9876SPeter Zijlstra	default y
2450f43b9876SPeter Zijlstra	depends on (X86_64 || X86_PAE)
2451f43b9876SPeter Zijlstra	help
2452f43b9876SPeter Zijlstra	  This feature reduces the number of hardware side channels by
2453f43b9876SPeter Zijlstra	  ensuring that the majority of kernel addresses are not mapped
2454f43b9876SPeter Zijlstra	  into userspace.
2455f43b9876SPeter Zijlstra
2456f43b9876SPeter Zijlstra	  See Documentation/x86/pti.rst for more details.
2457f43b9876SPeter Zijlstra
2458f43b9876SPeter Zijlstraconfig RETPOLINE
2459f43b9876SPeter Zijlstra	bool "Avoid speculative indirect branches in kernel"
2460f43b9876SPeter Zijlstra	select OBJTOOL if HAVE_OBJTOOL
2461f43b9876SPeter Zijlstra	default y
2462f43b9876SPeter Zijlstra	help
2463f43b9876SPeter Zijlstra	  Compile kernel with the retpoline compiler options to guard against
2464f43b9876SPeter Zijlstra	  kernel-to-user data leaks by avoiding speculative indirect
2465f43b9876SPeter Zijlstra	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2466f43b9876SPeter Zijlstra	  support for full protection. The kernel may run slower.
2467f43b9876SPeter Zijlstra
2468f43b9876SPeter Zijlstraconfig RETHUNK
2469f43b9876SPeter Zijlstra	bool "Enable return-thunks"
2470f43b9876SPeter Zijlstra	depends on RETPOLINE && CC_HAS_RETURN_THUNK
2471f43b9876SPeter Zijlstra	select OBJTOOL if HAVE_OBJTOOL
2472b648ab48SBen Hutchings	default y if X86_64
2473f43b9876SPeter Zijlstra	help
2474f43b9876SPeter Zijlstra	  Compile the kernel with the return-thunks compiler option to guard
2475f43b9876SPeter Zijlstra	  against kernel-to-user data leaks by avoiding return speculation.
2476f43b9876SPeter Zijlstra	  Requires a compiler with -mfunction-return=thunk-extern
2477f43b9876SPeter Zijlstra	  support for full protection. The kernel may run slower.
2478f43b9876SPeter Zijlstra
2479f43b9876SPeter Zijlstraconfig CPU_UNRET_ENTRY
2480f43b9876SPeter Zijlstra	bool "Enable UNRET on kernel entry"
2481b648ab48SBen Hutchings	depends on CPU_SUP_AMD && RETHUNK && X86_64
2482f43b9876SPeter Zijlstra	default y
2483f43b9876SPeter Zijlstra	help
2484f43b9876SPeter Zijlstra	  Compile the kernel with support for the retbleed=unret mitigation.
2485f43b9876SPeter Zijlstra
2486f43b9876SPeter Zijlstraconfig CPU_IBPB_ENTRY
2487f43b9876SPeter Zijlstra	bool "Enable IBPB on kernel entry"
2488b648ab48SBen Hutchings	depends on CPU_SUP_AMD && X86_64
2489f43b9876SPeter Zijlstra	default y
2490f43b9876SPeter Zijlstra	help
2491f43b9876SPeter Zijlstra	  Compile the kernel with support for the retbleed=ibpb mitigation.
2492f43b9876SPeter Zijlstra
2493f43b9876SPeter Zijlstraconfig CPU_IBRS_ENTRY
2494f43b9876SPeter Zijlstra	bool "Enable IBRS on kernel entry"
2495b648ab48SBen Hutchings	depends on CPU_SUP_INTEL && X86_64
2496f43b9876SPeter Zijlstra	default y
2497f43b9876SPeter Zijlstra	help
2498f43b9876SPeter Zijlstra	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2499f43b9876SPeter Zijlstra	  This mitigates both spectre_v2 and retbleed at great cost to
2500f43b9876SPeter Zijlstra	  performance.
2501f43b9876SPeter Zijlstra
2502f43b9876SPeter Zijlstraconfig SLS
2503f43b9876SPeter Zijlstra	bool "Mitigate Straight-Line-Speculation"
2504f43b9876SPeter Zijlstra	depends on CC_HAS_SLS && X86_64
2505f43b9876SPeter Zijlstra	select OBJTOOL if HAVE_OBJTOOL
2506f43b9876SPeter Zijlstra	default n
2507f43b9876SPeter Zijlstra	help
2508f43b9876SPeter Zijlstra	  Compile the kernel with straight-line-speculation options to guard
2509f43b9876SPeter Zijlstra	  against straight line speculation. The kernel image might be slightly
2510f43b9876SPeter Zijlstra	  larger.
2511f43b9876SPeter Zijlstra
2512f43b9876SPeter Zijlstraendif
2513f43b9876SPeter Zijlstra
25143072e413SMichal Hockoconfig ARCH_HAS_ADD_PAGES
25153072e413SMichal Hocko	def_bool y
25165c11f00bSDavid Hildenbrand	depends on ARCH_ENABLE_MEMORY_HOTPLUG
25173072e413SMichal Hocko
2518f91ef222SOscar Salvadorconfig ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2519f91ef222SOscar Salvador	def_bool y
2520f91ef222SOscar Salvador
2521da85f865SBjorn Helgaasmenu "Power management and ACPI options"
2522e279b6c1SSam Ravnborg
2523e279b6c1SSam Ravnborgconfig ARCH_HIBERNATION_HEADER
25243c2362e6SHarvey Harrison	def_bool y
252544556530SZhimin Gu	depends on HIBERNATION
2526e279b6c1SSam Ravnborg
2527e279b6c1SSam Ravnborgsource "kernel/power/Kconfig"
2528e279b6c1SSam Ravnborg
2529e279b6c1SSam Ravnborgsource "drivers/acpi/Kconfig"
2530e279b6c1SSam Ravnborg
2531a6b68076SAndi Kleenconfig X86_APM_BOOT
25326fc108a0SJan Beulich	def_bool y
2533282e5aabSPaul Bolle	depends on APM
2534a6b68076SAndi Kleen
2535e279b6c1SSam Ravnborgmenuconfig APM
2536e279b6c1SSam Ravnborg	tristate "APM (Advanced Power Management) BIOS support"
2537efefa6f6SIngo Molnar	depends on X86_32 && PM_SLEEP
2538a7f7f624SMasahiro Yamada	help
2539e279b6c1SSam Ravnborg	  APM is a BIOS specification for saving power using several different
2540e279b6c1SSam Ravnborg	  techniques. This is mostly useful for battery powered laptops with
2541e279b6c1SSam Ravnborg	  APM compliant BIOSes. If you say Y here, the system time will be
2542e279b6c1SSam Ravnborg	  reset after a RESUME operation, the /proc/apm device will provide
2543e279b6c1SSam Ravnborg	  battery status information, and user-space programs will receive
2544e279b6c1SSam Ravnborg	  notification of APM "events" (e.g. battery status change).
2545e279b6c1SSam Ravnborg
2546e279b6c1SSam Ravnborg	  If you select "Y" here, you can disable actual use of the APM
2547e279b6c1SSam Ravnborg	  BIOS by passing the "apm=off" option to the kernel at boot time.
2548e279b6c1SSam Ravnborg
2549e279b6c1SSam Ravnborg	  Note that the APM support is almost completely disabled for
2550e279b6c1SSam Ravnborg	  machines with more than one CPU.
2551e279b6c1SSam Ravnborg
2552e279b6c1SSam Ravnborg	  In order to use APM, you will need supporting software. For location
2553151f4e2bSMauro Carvalho Chehab	  and more information, read <file:Documentation/power/apm-acpi.rst>
25542dc98fd3SMichael Witten	  and the Battery Powered Linux mini-HOWTO, available from
2555e279b6c1SSam Ravnborg	  <http://www.tldp.org/docs.html#howto>.
2556e279b6c1SSam Ravnborg
2557e279b6c1SSam Ravnborg	  This driver does not spin down disk drives (see the hdparm(8)
2558e279b6c1SSam Ravnborg	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2559e279b6c1SSam Ravnborg	  VESA-compliant "green" monitors.
2560e279b6c1SSam Ravnborg
2561e279b6c1SSam Ravnborg	  This driver does not support the TI 4000M TravelMate and the ACER
2562e279b6c1SSam Ravnborg	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2563e279b6c1SSam Ravnborg	  desktop machines also don't have compliant BIOSes, and this driver
2564e279b6c1SSam Ravnborg	  may cause those machines to panic during the boot phase.
2565e279b6c1SSam Ravnborg
2566e279b6c1SSam Ravnborg	  Generally, if you don't have a battery in your machine, there isn't
2567e279b6c1SSam Ravnborg	  much point in using this driver and you should say N. If you get
2568e279b6c1SSam Ravnborg	  random kernel OOPSes or reboots that don't seem to be related to
2569e279b6c1SSam Ravnborg	  anything, try disabling/enabling this option (or disabling/enabling
2570e279b6c1SSam Ravnborg	  APM in your BIOS).
2571e279b6c1SSam Ravnborg
2572e279b6c1SSam Ravnborg	  Some other things you should try when experiencing seemingly random,
2573e279b6c1SSam Ravnborg	  "weird" problems:
2574e279b6c1SSam Ravnborg
2575e279b6c1SSam Ravnborg	  1) make sure that you have enough swap space and that it is
2576e279b6c1SSam Ravnborg	  enabled.
2577e279b6c1SSam Ravnborg	  2) pass the "no-hlt" option to the kernel
2578e279b6c1SSam Ravnborg	  3) switch on floating point emulation in the kernel and pass
2579e279b6c1SSam Ravnborg	  the "no387" option to the kernel
2580e279b6c1SSam Ravnborg	  4) pass the "floppy=nodma" option to the kernel
2581e279b6c1SSam Ravnborg	  5) pass the "mem=4M" option to the kernel (thereby disabling
2582e279b6c1SSam Ravnborg	  all but the first 4 MB of RAM)
2583e279b6c1SSam Ravnborg	  6) make sure that the CPU is not over clocked.
2584e279b6c1SSam Ravnborg	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2585e279b6c1SSam Ravnborg	  8) disable the cache from your BIOS settings
2586e279b6c1SSam Ravnborg	  9) install a fan for the video card or exchange video RAM
2587e279b6c1SSam Ravnborg	  10) install a better fan for the CPU
2588e279b6c1SSam Ravnborg	  11) exchange RAM chips
2589e279b6c1SSam Ravnborg	  12) exchange the motherboard.
2590e279b6c1SSam Ravnborg
2591e279b6c1SSam Ravnborg	  To compile this driver as a module, choose M here: the
2592e279b6c1SSam Ravnborg	  module will be called apm.
2593e279b6c1SSam Ravnborg
2594e279b6c1SSam Ravnborgif APM
2595e279b6c1SSam Ravnborg
2596e279b6c1SSam Ravnborgconfig APM_IGNORE_USER_SUSPEND
2597e279b6c1SSam Ravnborg	bool "Ignore USER SUSPEND"
2598a7f7f624SMasahiro Yamada	help
2599e279b6c1SSam Ravnborg	  This option will ignore USER SUSPEND requests. On machines with a
2600e279b6c1SSam Ravnborg	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2601e279b6c1SSam Ravnborg	  series notebooks, it is necessary to say Y because of a BIOS bug.
2602e279b6c1SSam Ravnborg
2603e279b6c1SSam Ravnborgconfig APM_DO_ENABLE
2604e279b6c1SSam Ravnborg	bool "Enable PM at boot time"
2605a7f7f624SMasahiro Yamada	help
2606e279b6c1SSam Ravnborg	  Enable APM features at boot time. From page 36 of the APM BIOS
2607e279b6c1SSam Ravnborg	  specification: "When disabled, the APM BIOS does not automatically
2608e279b6c1SSam Ravnborg	  power manage devices, enter the Standby State, enter the Suspend
2609e279b6c1SSam Ravnborg	  State, or take power saving steps in response to CPU Idle calls."
2610e279b6c1SSam Ravnborg	  This driver will make CPU Idle calls when Linux is idle (unless this
2611e279b6c1SSam Ravnborg	  feature is turned off -- see "Do CPU IDLE calls", below). This
2612e279b6c1SSam Ravnborg	  should always save battery power, but more complicated APM features
2613e279b6c1SSam Ravnborg	  will be dependent on your BIOS implementation. You may need to turn
2614e279b6c1SSam Ravnborg	  this option off if your computer hangs at boot time when using APM
2615e279b6c1SSam Ravnborg	  support, or if it beeps continuously instead of suspending. Turn
2616e279b6c1SSam Ravnborg	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2617e279b6c1SSam Ravnborg	  T400CDT. This is off by default since most machines do fine without
2618e279b6c1SSam Ravnborg	  this feature.
2619e279b6c1SSam Ravnborg
2620e279b6c1SSam Ravnborgconfig APM_CPU_IDLE
2621dd8af076SLen Brown	depends on CPU_IDLE
2622e279b6c1SSam Ravnborg	bool "Make CPU Idle calls when idle"
2623a7f7f624SMasahiro Yamada	help
2624e279b6c1SSam Ravnborg	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2625e279b6c1SSam Ravnborg	  On some machines, this can activate improved power savings, such as
2626e279b6c1SSam Ravnborg	  a slowed CPU clock rate, when the machine is idle. These idle calls
2627e279b6c1SSam Ravnborg	  are made after the idle loop has run for some length of time (e.g.,
2628e279b6c1SSam Ravnborg	  333 mS). On some machines, this will cause a hang at boot time or
2629e279b6c1SSam Ravnborg	  whenever the CPU becomes idle. (On machines with more than one CPU,
2630e279b6c1SSam Ravnborg	  this option does nothing.)
2631e279b6c1SSam Ravnborg
2632e279b6c1SSam Ravnborgconfig APM_DISPLAY_BLANK
2633e279b6c1SSam Ravnborg	bool "Enable console blanking using APM"
2634a7f7f624SMasahiro Yamada	help
2635e279b6c1SSam Ravnborg	  Enable console blanking using the APM. Some laptops can use this to
2636e279b6c1SSam Ravnborg	  turn off the LCD backlight when the screen blanker of the Linux
2637e279b6c1SSam Ravnborg	  virtual console blanks the screen. Note that this is only used by
2638e279b6c1SSam Ravnborg	  the virtual console screen blanker, and won't turn off the backlight
2639e279b6c1SSam Ravnborg	  when using the X Window system. This also doesn't have anything to
2640e279b6c1SSam Ravnborg	  do with your VESA-compliant power-saving monitor. Further, this
2641e279b6c1SSam Ravnborg	  option doesn't work for all laptops -- it might not turn off your
2642e279b6c1SSam Ravnborg	  backlight at all, or it might print a lot of errors to the console,
2643e279b6c1SSam Ravnborg	  especially if you are using gpm.
2644e279b6c1SSam Ravnborg
2645e279b6c1SSam Ravnborgconfig APM_ALLOW_INTS
2646e279b6c1SSam Ravnborg	bool "Allow interrupts during APM BIOS calls"
2647a7f7f624SMasahiro Yamada	help
2648e279b6c1SSam Ravnborg	  Normally we disable external interrupts while we are making calls to
2649e279b6c1SSam Ravnborg	  the APM BIOS as a measure to lessen the effects of a badly behaving
2650e279b6c1SSam Ravnborg	  BIOS implementation.  The BIOS should reenable interrupts if it
2651e279b6c1SSam Ravnborg	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2652e279b6c1SSam Ravnborg	  many of the newer IBM Thinkpads.  If you experience hangs when you
2653e279b6c1SSam Ravnborg	  suspend, try setting this to Y.  Otherwise, say N.
2654e279b6c1SSam Ravnborg
2655e279b6c1SSam Ravnborgendif # APM
2656e279b6c1SSam Ravnborg
2657bb0a56ecSDave Jonessource "drivers/cpufreq/Kconfig"
2658e279b6c1SSam Ravnborg
2659e279b6c1SSam Ravnborgsource "drivers/cpuidle/Kconfig"
2660e279b6c1SSam Ravnborg
266127471fdbSAndy Henroidsource "drivers/idle/Kconfig"
266227471fdbSAndy Henroid
2663e279b6c1SSam Ravnborgendmenu
2664e279b6c1SSam Ravnborg
2665e279b6c1SSam Ravnborgmenu "Bus options (PCI etc.)"
2666e279b6c1SSam Ravnborg
2667e279b6c1SSam Ravnborgchoice
2668e279b6c1SSam Ravnborg	prompt "PCI access mode"
2669efefa6f6SIngo Molnar	depends on X86_32 && PCI
2670e279b6c1SSam Ravnborg	default PCI_GOANY
2671a7f7f624SMasahiro Yamada	help
2672e279b6c1SSam Ravnborg	  On PCI systems, the BIOS can be used to detect the PCI devices and
2673e279b6c1SSam Ravnborg	  determine their configuration. However, some old PCI motherboards
2674e279b6c1SSam Ravnborg	  have BIOS bugs and may crash if this is done. Also, some embedded
2675e279b6c1SSam Ravnborg	  PCI-based systems don't have any BIOS at all. Linux can also try to
2676e279b6c1SSam Ravnborg	  detect the PCI hardware directly without using the BIOS.
2677e279b6c1SSam Ravnborg
2678e279b6c1SSam Ravnborg	  With this option, you can specify how Linux should detect the
2679e279b6c1SSam Ravnborg	  PCI devices. If you choose "BIOS", the BIOS will be used,
2680e279b6c1SSam Ravnborg	  if you choose "Direct", the BIOS won't be used, and if you
2681e279b6c1SSam Ravnborg	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2682e279b6c1SSam Ravnborg	  If you choose "Any", the kernel will try MMCONFIG, then the
2683e279b6c1SSam Ravnborg	  direct access method and falls back to the BIOS if that doesn't
2684e279b6c1SSam Ravnborg	  work. If unsure, go with the default, which is "Any".
2685e279b6c1SSam Ravnborg
2686e279b6c1SSam Ravnborgconfig PCI_GOBIOS
2687e279b6c1SSam Ravnborg	bool "BIOS"
2688e279b6c1SSam Ravnborg
2689e279b6c1SSam Ravnborgconfig PCI_GOMMCONFIG
2690e279b6c1SSam Ravnborg	bool "MMConfig"
2691e279b6c1SSam Ravnborg
2692e279b6c1SSam Ravnborgconfig PCI_GODIRECT
2693e279b6c1SSam Ravnborg	bool "Direct"
2694e279b6c1SSam Ravnborg
26953ef0e1f8SAndres Salomonconfig PCI_GOOLPC
269676fb6570SDaniel Drake	bool "OLPC XO-1"
26973ef0e1f8SAndres Salomon	depends on OLPC
26983ef0e1f8SAndres Salomon
26992bdd1b03SAndres Salomonconfig PCI_GOANY
27002bdd1b03SAndres Salomon	bool "Any"
27012bdd1b03SAndres Salomon
2702e279b6c1SSam Ravnborgendchoice
2703e279b6c1SSam Ravnborg
2704e279b6c1SSam Ravnborgconfig PCI_BIOS
27053c2362e6SHarvey Harrison	def_bool y
2706efefa6f6SIngo Molnar	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2707e279b6c1SSam Ravnborg
2708e279b6c1SSam Ravnborg# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2709e279b6c1SSam Ravnborgconfig PCI_DIRECT
27103c2362e6SHarvey Harrison	def_bool y
27110aba496fSShaohua Li	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2712e279b6c1SSam Ravnborg
2713e279b6c1SSam Ravnborgconfig PCI_MMCONFIG
2714b45c9f36SJan Kiszka	bool "Support mmconfig PCI config space access" if X86_64
2715b45c9f36SJan Kiszka	default y
27164590d98fSAndy Shevchenko	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2717b45c9f36SJan Kiszka	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2718e279b6c1SSam Ravnborg
27193ef0e1f8SAndres Salomonconfig PCI_OLPC
27202bdd1b03SAndres Salomon	def_bool y
27212bdd1b03SAndres Salomon	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
27223ef0e1f8SAndres Salomon
2723b5401a96SAlex Nixonconfig PCI_XEN
2724b5401a96SAlex Nixon	def_bool y
2725b5401a96SAlex Nixon	depends on PCI && XEN
2726b5401a96SAlex Nixon
27278364e1f8SJan Kiszkaconfig MMCONF_FAM10H
27288364e1f8SJan Kiszka	def_bool y
27298364e1f8SJan Kiszka	depends on X86_64 && PCI_MMCONFIG && ACPI
2730e279b6c1SSam Ravnborg
27313f6ea84aSIra W. Snyderconfig PCI_CNB20LE_QUIRK
27326a108a14SDavid Rientjes	bool "Read CNB20LE Host Bridge Windows" if EXPERT
27336ea30386SKees Cook	depends on PCI
27343f6ea84aSIra W. Snyder	help
27353f6ea84aSIra W. Snyder	  Read the PCI windows out of the CNB20LE host bridge. This allows
27363f6ea84aSIra W. Snyder	  PCI hotplug to work on systems with the CNB20LE chipset which do
27373f6ea84aSIra W. Snyder	  not have ACPI.
27383f6ea84aSIra W. Snyder
273964a5fed6SBjorn Helgaas	  There's no public spec for this chipset, and this functionality
274064a5fed6SBjorn Helgaas	  is known to be incomplete.
274164a5fed6SBjorn Helgaas
274264a5fed6SBjorn Helgaas	  You should say N unless you know you need this.
274364a5fed6SBjorn Helgaas
27443a495511SWilliam Breathitt Grayconfig ISA_BUS
274517a2a129SWilliam Breathitt Gray	bool "ISA bus support on modern systems" if EXPERT
27463a495511SWilliam Breathitt Gray	help
274717a2a129SWilliam Breathitt Gray	  Expose ISA bus device drivers and options available for selection and
274817a2a129SWilliam Breathitt Gray	  configuration. Enable this option if your target machine has an ISA
274917a2a129SWilliam Breathitt Gray	  bus. ISA is an older system, displaced by PCI and newer bus
275017a2a129SWilliam Breathitt Gray	  architectures -- if your target machine is modern, it probably does
275117a2a129SWilliam Breathitt Gray	  not have an ISA bus.
27523a495511SWilliam Breathitt Gray
27533a495511SWilliam Breathitt Gray	  If unsure, say N.
27543a495511SWilliam Breathitt Gray
27551c00f016SDavid Rientjes# x86_64 have no ISA slots, but can have ISA-style DMA.
2756e279b6c1SSam Ravnborgconfig ISA_DMA_API
27571c00f016SDavid Rientjes	bool "ISA-style DMA support" if (X86_64 && EXPERT)
27581c00f016SDavid Rientjes	default y
27591c00f016SDavid Rientjes	help
27601c00f016SDavid Rientjes	  Enables ISA-style DMA support for devices requiring such controllers.
27611c00f016SDavid Rientjes	  If unsure, say Y.
2762e279b6c1SSam Ravnborg
276351e68d05SLinus Torvaldsif X86_32
276451e68d05SLinus Torvalds
2765e279b6c1SSam Ravnborgconfig ISA
2766e279b6c1SSam Ravnborg	bool "ISA support"
2767a7f7f624SMasahiro Yamada	help
2768e279b6c1SSam Ravnborg	  Find out whether you have ISA slots on your motherboard.  ISA is the
2769e279b6c1SSam Ravnborg	  name of a bus system, i.e. the way the CPU talks to the other stuff
2770e279b6c1SSam Ravnborg	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2771e279b6c1SSam Ravnborg	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2772e279b6c1SSam Ravnborg	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2773e279b6c1SSam Ravnborg
2774e279b6c1SSam Ravnborgconfig SCx200
2775e279b6c1SSam Ravnborg	tristate "NatSemi SCx200 support"
2776a7f7f624SMasahiro Yamada	help
2777e279b6c1SSam Ravnborg	  This provides basic support for National Semiconductor's
2778e279b6c1SSam Ravnborg	  (now AMD's) Geode processors.  The driver probes for the
2779e279b6c1SSam Ravnborg	  PCI-IDs of several on-chip devices, so its a good dependency
2780e279b6c1SSam Ravnborg	  for other scx200_* drivers.
2781e279b6c1SSam Ravnborg
2782e279b6c1SSam Ravnborg	  If compiled as a module, the driver is named scx200.
2783e279b6c1SSam Ravnborg
2784e279b6c1SSam Ravnborgconfig SCx200HR_TIMER
2785e279b6c1SSam Ravnborg	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2786592913ecSJohn Stultz	depends on SCx200
2787e279b6c1SSam Ravnborg	default y
2788a7f7f624SMasahiro Yamada	help
2789e279b6c1SSam Ravnborg	  This driver provides a clocksource built upon the on-chip
2790e279b6c1SSam Ravnborg	  27MHz high-resolution timer.  Its also a workaround for
2791e279b6c1SSam Ravnborg	  NSC Geode SC-1100's buggy TSC, which loses time when the
2792e279b6c1SSam Ravnborg	  processor goes idle (as is done by the scheduler).  The
2793e279b6c1SSam Ravnborg	  other workaround is idle=poll boot option.
2794e279b6c1SSam Ravnborg
27953ef0e1f8SAndres Salomonconfig OLPC
27963ef0e1f8SAndres Salomon	bool "One Laptop Per Child support"
279754008979SThomas Gleixner	depends on !X86_PAE
27983c554946SAndres Salomon	select GPIOLIB
2799dc3119e7SThomas Gleixner	select OF
280045bb1674SDaniel Drake	select OF_PROMTREE
2801b4e51854SGrant Likely	select IRQ_DOMAIN
28020c3d931bSLubomir Rintel	select OLPC_EC
2803a7f7f624SMasahiro Yamada	help
28043ef0e1f8SAndres Salomon	  Add support for detecting the unique features of the OLPC
28053ef0e1f8SAndres Salomon	  XO hardware.
28063ef0e1f8SAndres Salomon
2807a3128588SDaniel Drakeconfig OLPC_XO1_PM
2808a3128588SDaniel Drake	bool "OLPC XO-1 Power Management"
2809fa112cf1SBorislav Petkov	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2810a7f7f624SMasahiro Yamada	help
281197c4cb71SDaniel Drake	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2812bf1ebf00SDaniel Drake
2813cfee9597SDaniel Drakeconfig OLPC_XO1_RTC
2814cfee9597SDaniel Drake	bool "OLPC XO-1 Real Time Clock"
2815cfee9597SDaniel Drake	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2816a7f7f624SMasahiro Yamada	help
2817cfee9597SDaniel Drake	  Add support for the XO-1 real time clock, which can be used as a
2818cfee9597SDaniel Drake	  programmable wakeup source.
2819cfee9597SDaniel Drake
28207feda8e9SDaniel Drakeconfig OLPC_XO1_SCI
28217feda8e9SDaniel Drake	bool "OLPC XO-1 SCI extras"
282292e830f2SArnd Bergmann	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2823ed8e47feSRandy Dunlap	depends on INPUT=y
2824d8d01a63SDaniel Drake	select POWER_SUPPLY
2825a7f7f624SMasahiro Yamada	help
28267feda8e9SDaniel Drake	  Add support for SCI-based features of the OLPC XO-1 laptop:
28277bc74b3dSDaniel Drake	   - EC-driven system wakeups
28287feda8e9SDaniel Drake	   - Power button
28297bc74b3dSDaniel Drake	   - Ebook switch
28302cf2baeaSDaniel Drake	   - Lid switch
2831e1040ac6SDaniel Drake	   - AC adapter status updates
2832e1040ac6SDaniel Drake	   - Battery status updates
28337feda8e9SDaniel Drake
2834a0f30f59SDaniel Drakeconfig OLPC_XO15_SCI
2835a0f30f59SDaniel Drake	bool "OLPC XO-1.5 SCI extras"
2836d8d01a63SDaniel Drake	depends on OLPC && ACPI
2837d8d01a63SDaniel Drake	select POWER_SUPPLY
2838a7f7f624SMasahiro Yamada	help
2839a0f30f59SDaniel Drake	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2840a0f30f59SDaniel Drake	   - EC-driven system wakeups
2841a0f30f59SDaniel Drake	   - AC adapter status updates
2842a0f30f59SDaniel Drake	   - Battery status updates
2843e279b6c1SSam Ravnborg
2844d4f3e350SEd Wildgooseconfig ALIX
2845d4f3e350SEd Wildgoose	bool "PCEngines ALIX System Support (LED setup)"
2846d4f3e350SEd Wildgoose	select GPIOLIB
2847a7f7f624SMasahiro Yamada	help
2848d4f3e350SEd Wildgoose	  This option enables system support for the PCEngines ALIX.
2849d4f3e350SEd Wildgoose	  At present this just sets up LEDs for GPIO control on
2850d4f3e350SEd Wildgoose	  ALIX2/3/6 boards.  However, other system specific setup should
2851d4f3e350SEd Wildgoose	  get added here.
2852d4f3e350SEd Wildgoose
2853d4f3e350SEd Wildgoose	  Note: You must still enable the drivers for GPIO and LED support
2854d4f3e350SEd Wildgoose	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2855d4f3e350SEd Wildgoose
2856d4f3e350SEd Wildgoose	  Note: You have to set alix.force=1 for boards with Award BIOS.
2857d4f3e350SEd Wildgoose
2858da4e3302SPhilip Prindevilleconfig NET5501
2859da4e3302SPhilip Prindeville	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2860da4e3302SPhilip Prindeville	select GPIOLIB
2861a7f7f624SMasahiro Yamada	help
2862da4e3302SPhilip Prindeville	  This option enables system support for the Soekris Engineering net5501.
2863da4e3302SPhilip Prindeville
28643197059aSPhilip A. Prindevilleconfig GEOS
28653197059aSPhilip A. Prindeville	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
28663197059aSPhilip A. Prindeville	select GPIOLIB
28673197059aSPhilip A. Prindeville	depends on DMI
2868a7f7f624SMasahiro Yamada	help
28693197059aSPhilip A. Prindeville	  This option enables system support for the Traverse Technologies GEOS.
28703197059aSPhilip A. Prindeville
28717d029125SVivien Didelotconfig TS5500
28727d029125SVivien Didelot	bool "Technologic Systems TS-5500 platform support"
28737d029125SVivien Didelot	depends on MELAN
28747d029125SVivien Didelot	select CHECK_SIGNATURE
28757d029125SVivien Didelot	select NEW_LEDS
28767d029125SVivien Didelot	select LEDS_CLASS
2877a7f7f624SMasahiro Yamada	help
28787d029125SVivien Didelot	  This option enables system support for the Technologic Systems TS-5500.
28797d029125SVivien Didelot
2880e279b6c1SSam Ravnborgendif # X86_32
2881e279b6c1SSam Ravnborg
288223ac4ae8SAndreas Herrmannconfig AMD_NB
2883e279b6c1SSam Ravnborg	def_bool y
28840e152cd7SBorislav Petkov	depends on CPU_SUP_AMD && PCI
2885e279b6c1SSam Ravnborg
2886e279b6c1SSam Ravnborgendmenu
2887e279b6c1SSam Ravnborg
28881572497cSChristoph Hellwigmenu "Binary Emulations"
2889e279b6c1SSam Ravnborg
2890e279b6c1SSam Ravnborgconfig IA32_EMULATION
2891e279b6c1SSam Ravnborg	bool "IA32 Emulation"
2892e279b6c1SSam Ravnborg	depends on X86_64
289339f88911SIngo Molnar	select ARCH_WANT_OLD_COMPAT_IPC
2894d1603990SRandy Dunlap	select BINFMT_ELF
289539f88911SIngo Molnar	select COMPAT_OLD_SIGACTION
2896a7f7f624SMasahiro Yamada	help
28975fd92e65SH. J. Lu	  Include code to run legacy 32-bit programs under a
28985fd92e65SH. J. Lu	  64-bit kernel. You should likely turn this on, unless you're
28995fd92e65SH. J. Lu	  100% sure that you don't have any 32-bit programs left.
2900e279b6c1SSam Ravnborg
290183a44a4fSMasahiro Yamadaconfig X86_X32_ABI
29026ea30386SKees Cook	bool "x32 ABI for 64-bit mode"
29039b54050bSBrian Gerst	depends on X86_64
2904aaeed6ecSNathan Chancellor	# llvm-objcopy does not convert x86_64 .note.gnu.property or
2905aaeed6ecSNathan Chancellor	# compressed debug sections to x86_x32 properly:
2906aaeed6ecSNathan Chancellor	# https://github.com/ClangBuiltLinux/linux/issues/514
2907aaeed6ecSNathan Chancellor	# https://github.com/ClangBuiltLinux/linux/issues/1141
2908aaeed6ecSNathan Chancellor	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
2909a7f7f624SMasahiro Yamada	help
29105fd92e65SH. J. Lu	  Include code to run binaries for the x32 native 32-bit ABI
29115fd92e65SH. J. Lu	  for 64-bit processors.  An x32 process gets access to the
29125fd92e65SH. J. Lu	  full 64-bit register file and wide data path while leaving
29135fd92e65SH. J. Lu	  pointers at 32 bits for smaller memory footprint.
29145fd92e65SH. J. Lu
2915953fee1dSIngo Molnarconfig COMPAT_32
2916953fee1dSIngo Molnar	def_bool y
2917953fee1dSIngo Molnar	depends on IA32_EMULATION || X86_32
2918953fee1dSIngo Molnar	select HAVE_UID16
2919953fee1dSIngo Molnar	select OLD_SIGSUSPEND3
2920953fee1dSIngo Molnar
2921e279b6c1SSam Ravnborgconfig COMPAT
29223c2362e6SHarvey Harrison	def_bool y
292383a44a4fSMasahiro Yamada	depends on IA32_EMULATION || X86_X32_ABI
2924e279b6c1SSam Ravnborg
2925e279b6c1SSam Ravnborgconfig COMPAT_FOR_U64_ALIGNMENT
29263120e25eSJan Beulich	def_bool y
2927a9251280SLinus Torvalds	depends on COMPAT
2928ee009e4aSDavid Howells
2929e279b6c1SSam Ravnborgendmenu
2930e279b6c1SSam Ravnborg
2931e5beae16SKeith Packardconfig HAVE_ATOMIC_IOMAP
2932e5beae16SKeith Packard	def_bool y
2933e5beae16SKeith Packard	depends on X86_32
2934e5beae16SKeith Packard
2935edf88417SAvi Kivitysource "arch/x86/kvm/Kconfig"
29365e8ebd84SJason A. Donenfeld
29375e8ebd84SJason A. Donenfeldsource "arch/x86/Kconfig.assembler"
2938