xref: /linux/arch/x86/Kconfig (revision 26dca6dbd62d74a5012cafab6b2d6d65a01ea69c)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	---help---
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select HAVE_DEBUG_STACKOVERFLOW
18	select MODULES_USE_ELF_REL
19	select OLD_SIGACTION
20	select GENERIC_VDSO_32
21
22config X86_64
23	def_bool y
24	depends on 64BIT
25	# Options that are inherently 64-bit kernel only:
26	select ARCH_HAS_GIGANTIC_PAGE
27	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
28	select ARCH_USE_CMPXCHG_LOCKREF
29	select HAVE_ARCH_SOFT_DIRTY
30	select MODULES_USE_ELF_RELA
31	select NEED_DMA_MAP_STATE
32	select SWIOTLB
33	select ARCH_HAS_SYSCALL_WRAPPER
34
35config FORCE_DYNAMIC_FTRACE
36	def_bool y
37	depends on X86_32
38	depends on FUNCTION_TRACER
39	select DYNAMIC_FTRACE
40	help
41	 We keep the static function tracing (!DYNAMIC_FTRACE) around
42	 in order to test the non static function tracing in the
43	 generic code, as other architectures still use it. But we
44	 only need to keep it around for x86_64. No need to keep it
45	 for x86_32. For x86_32, force DYNAMIC_FTRACE.
46#
47# Arch settings
48#
49# ( Note that options that are marked 'if X86_64' could in principle be
50#   ported to 32-bit as well. )
51#
52config X86
53	def_bool y
54	#
55	# Note: keep this list sorted alphabetically
56	#
57	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
58	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
59	select ARCH_32BIT_OFF_T			if X86_32
60	select ARCH_CLOCKSOURCE_DATA
61	select ARCH_CLOCKSOURCE_INIT
62	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
63	select ARCH_HAS_DEBUG_VIRTUAL
64	select ARCH_HAS_DEVMEM_IS_ALLOWED
65	select ARCH_HAS_ELF_RANDOMIZE
66	select ARCH_HAS_FAST_MULTIPLIER
67	select ARCH_HAS_FILTER_PGPROT
68	select ARCH_HAS_FORTIFY_SOURCE
69	select ARCH_HAS_GCOV_PROFILE_ALL
70	select ARCH_HAS_KCOV			if X86_64
71	select ARCH_HAS_MEM_ENCRYPT
72	select ARCH_HAS_MEMBARRIER_SYNC_CORE
73	select ARCH_HAS_PMEM_API		if X86_64
74	select ARCH_HAS_PTE_DEVMAP		if X86_64
75	select ARCH_HAS_PTE_SPECIAL
76	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
77	select ARCH_HAS_UACCESS_MCSAFE		if X86_64 && X86_MCE
78	select ARCH_HAS_SET_MEMORY
79	select ARCH_HAS_SET_DIRECT_MAP
80	select ARCH_HAS_STRICT_KERNEL_RWX
81	select ARCH_HAS_STRICT_MODULE_RWX
82	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
83	select ARCH_HAS_UBSAN_SANITIZE_ALL
84	select ARCH_HAVE_NMI_SAFE_CMPXCHG
85	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
86	select ARCH_MIGHT_HAVE_PC_PARPORT
87	select ARCH_MIGHT_HAVE_PC_SERIO
88	select ARCH_STACKWALK
89	select ARCH_SUPPORTS_ACPI
90	select ARCH_SUPPORTS_ATOMIC_RMW
91	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
92	select ARCH_USE_BUILTIN_BSWAP
93	select ARCH_USE_QUEUED_RWLOCKS
94	select ARCH_USE_QUEUED_SPINLOCKS
95	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
96	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
97	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
98	select ARCH_WANT_HUGE_PMD_SHARE
99	select ARCH_WANTS_THP_SWAP		if X86_64
100	select BUILDTIME_TABLE_SORT
101	select CLKEVT_I8253
102	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
103	select CLOCKSOURCE_WATCHDOG
104	select DCACHE_WORD_ACCESS
105	select EDAC_ATOMIC_SCRUB
106	select EDAC_SUPPORT
107	select GENERIC_CLOCKEVENTS
108	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
109	select GENERIC_CLOCKEVENTS_MIN_ADJUST
110	select GENERIC_CMOS_UPDATE
111	select GENERIC_CPU_AUTOPROBE
112	select GENERIC_CPU_VULNERABILITIES
113	select GENERIC_EARLY_IOREMAP
114	select GENERIC_FIND_FIRST_BIT
115	select GENERIC_IOMAP
116	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
117	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
118	select GENERIC_IRQ_MIGRATION		if SMP
119	select GENERIC_IRQ_PROBE
120	select GENERIC_IRQ_RESERVATION_MODE
121	select GENERIC_IRQ_SHOW
122	select GENERIC_PENDING_IRQ		if SMP
123	select GENERIC_SMP_IDLE_THREAD
124	select GENERIC_STRNCPY_FROM_USER
125	select GENERIC_STRNLEN_USER
126	select GENERIC_TIME_VSYSCALL
127	select GENERIC_GETTIMEOFDAY
128	select GENERIC_VDSO_TIME_NS
129	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
130	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
131	select HAVE_ACPI_APEI			if ACPI
132	select HAVE_ACPI_APEI_NMI		if ACPI
133	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
134	select HAVE_ARCH_AUDITSYSCALL
135	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
136	select HAVE_ARCH_JUMP_LABEL
137	select HAVE_ARCH_JUMP_LABEL_RELATIVE
138	select HAVE_ARCH_KASAN			if X86_64
139	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
140	select HAVE_ARCH_KGDB
141	select HAVE_ARCH_MMAP_RND_BITS		if MMU
142	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
143	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
144	select HAVE_ARCH_PREL32_RELOCATIONS
145	select HAVE_ARCH_SECCOMP_FILTER
146	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
147	select HAVE_ARCH_STACKLEAK
148	select HAVE_ARCH_TRACEHOOK
149	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
150	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
151	select HAVE_ARCH_VMAP_STACK		if X86_64
152	select HAVE_ARCH_WITHIN_STACK_FRAMES
153	select HAVE_ASM_MODVERSIONS
154	select HAVE_CMPXCHG_DOUBLE
155	select HAVE_CMPXCHG_LOCAL
156	select HAVE_CONTEXT_TRACKING		if X86_64
157	select HAVE_COPY_THREAD_TLS
158	select HAVE_C_RECORDMCOUNT
159	select HAVE_DEBUG_KMEMLEAK
160	select HAVE_DMA_CONTIGUOUS
161	select HAVE_DYNAMIC_FTRACE
162	select HAVE_DYNAMIC_FTRACE_WITH_REGS
163	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
164	select HAVE_EBPF_JIT
165	select HAVE_EFFICIENT_UNALIGNED_ACCESS
166	select HAVE_EISA
167	select HAVE_EXIT_THREAD
168	select HAVE_FAST_GUP
169	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
170	select HAVE_FTRACE_MCOUNT_RECORD
171	select HAVE_FUNCTION_GRAPH_TRACER
172	select HAVE_FUNCTION_TRACER
173	select HAVE_GCC_PLUGINS
174	select HAVE_HW_BREAKPOINT
175	select HAVE_IDE
176	select HAVE_IOREMAP_PROT
177	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
178	select HAVE_IRQ_TIME_ACCOUNTING
179	select HAVE_KERNEL_BZIP2
180	select HAVE_KERNEL_GZIP
181	select HAVE_KERNEL_LZ4
182	select HAVE_KERNEL_LZMA
183	select HAVE_KERNEL_LZO
184	select HAVE_KERNEL_XZ
185	select HAVE_KPROBES
186	select HAVE_KPROBES_ON_FTRACE
187	select HAVE_FUNCTION_ERROR_INJECTION
188	select HAVE_KRETPROBES
189	select HAVE_KVM
190	select HAVE_LIVEPATCH			if X86_64
191	select HAVE_MEMBLOCK_NODE_MAP
192	select HAVE_MIXED_BREAKPOINTS_REGS
193	select HAVE_MOD_ARCH_SPECIFIC
194	select HAVE_MOVE_PMD
195	select HAVE_NMI
196	select HAVE_OPROFILE
197	select HAVE_OPTPROBES
198	select HAVE_PCSPKR_PLATFORM
199	select HAVE_PERF_EVENTS
200	select HAVE_PERF_EVENTS_NMI
201	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
202	select HAVE_PCI
203	select HAVE_PERF_REGS
204	select HAVE_PERF_USER_STACK_DUMP
205	select HAVE_RCU_TABLE_FREE		if PARAVIRT
206	select HAVE_REGS_AND_STACK_ACCESS_API
207	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
208	select HAVE_FUNCTION_ARG_ACCESS_API
209	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
210	select HAVE_STACK_VALIDATION		if X86_64
211	select HAVE_RSEQ
212	select HAVE_SYSCALL_TRACEPOINTS
213	select HAVE_UNSTABLE_SCHED_CLOCK
214	select HAVE_USER_RETURN_NOTIFIER
215	select HAVE_GENERIC_VDSO
216	select HOTPLUG_SMT			if SMP
217	select IRQ_FORCED_THREADING
218	select NEED_SG_DMA_LENGTH
219	select PCI_DOMAINS			if PCI
220	select PCI_LOCKLESS_CONFIG		if PCI
221	select PERF_EVENTS
222	select RTC_LIB
223	select RTC_MC146818_LIB
224	select SPARSE_IRQ
225	select SRCU
226	select SYSCTL_EXCEPTION_TRACE
227	select THREAD_INFO_IN_TASK
228	select USER_STACKTRACE_SUPPORT
229	select VIRT_TO_BUS
230	select X86_FEATURE_NAMES		if PROC_FS
231	select PROC_PID_ARCH_STATUS		if PROC_FS
232
233config INSTRUCTION_DECODER
234	def_bool y
235	depends on KPROBES || PERF_EVENTS || UPROBES
236
237config OUTPUT_FORMAT
238	string
239	default "elf32-i386" if X86_32
240	default "elf64-x86-64" if X86_64
241
242config ARCH_DEFCONFIG
243	string
244	default "arch/x86/configs/i386_defconfig" if X86_32
245	default "arch/x86/configs/x86_64_defconfig" if X86_64
246
247config LOCKDEP_SUPPORT
248	def_bool y
249
250config STACKTRACE_SUPPORT
251	def_bool y
252
253config MMU
254	def_bool y
255
256config ARCH_MMAP_RND_BITS_MIN
257	default 28 if 64BIT
258	default 8
259
260config ARCH_MMAP_RND_BITS_MAX
261	default 32 if 64BIT
262	default 16
263
264config ARCH_MMAP_RND_COMPAT_BITS_MIN
265	default 8
266
267config ARCH_MMAP_RND_COMPAT_BITS_MAX
268	default 16
269
270config SBUS
271	bool
272
273config GENERIC_ISA_DMA
274	def_bool y
275	depends on ISA_DMA_API
276
277config GENERIC_BUG
278	def_bool y
279	depends on BUG
280	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
281
282config GENERIC_BUG_RELATIVE_POINTERS
283	bool
284
285config ARCH_MAY_HAVE_PC_FDC
286	def_bool y
287	depends on ISA_DMA_API
288
289config GENERIC_CALIBRATE_DELAY
290	def_bool y
291
292config ARCH_HAS_CPU_RELAX
293	def_bool y
294
295config ARCH_HAS_CACHE_LINE_SIZE
296	def_bool y
297
298config ARCH_HAS_FILTER_PGPROT
299	def_bool y
300
301config HAVE_SETUP_PER_CPU_AREA
302	def_bool y
303
304config NEED_PER_CPU_EMBED_FIRST_CHUNK
305	def_bool y
306
307config NEED_PER_CPU_PAGE_FIRST_CHUNK
308	def_bool y
309
310config ARCH_HIBERNATION_POSSIBLE
311	def_bool y
312
313config ARCH_SUSPEND_POSSIBLE
314	def_bool y
315
316config ARCH_WANT_GENERAL_HUGETLB
317	def_bool y
318
319config ZONE_DMA32
320	def_bool y if X86_64
321
322config AUDIT_ARCH
323	def_bool y if X86_64
324
325config ARCH_SUPPORTS_DEBUG_PAGEALLOC
326	def_bool y
327
328config KASAN_SHADOW_OFFSET
329	hex
330	depends on KASAN
331	default 0xdffffc0000000000
332
333config HAVE_INTEL_TXT
334	def_bool y
335	depends on INTEL_IOMMU && ACPI
336
337config X86_32_SMP
338	def_bool y
339	depends on X86_32 && SMP
340
341config X86_64_SMP
342	def_bool y
343	depends on X86_64 && SMP
344
345config X86_32_LAZY_GS
346	def_bool y
347	depends on X86_32 && !STACKPROTECTOR
348
349config ARCH_SUPPORTS_UPROBES
350	def_bool y
351
352config FIX_EARLYCON_MEM
353	def_bool y
354
355config DYNAMIC_PHYSICAL_MASK
356	bool
357
358config PGTABLE_LEVELS
359	int
360	default 5 if X86_5LEVEL
361	default 4 if X86_64
362	default 3 if X86_PAE
363	default 2
364
365config CC_HAS_SANE_STACKPROTECTOR
366	bool
367	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
368	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
369	help
370	   We have to make sure stack protector is unconditionally disabled if
371	   the compiler produces broken code.
372
373menu "Processor type and features"
374
375config ZONE_DMA
376	bool "DMA memory allocation support" if EXPERT
377	default y
378	help
379	  DMA memory allocation support allows devices with less than 32-bit
380	  addressing to allocate within the first 16MB of address space.
381	  Disable if no such devices will be used.
382
383	  If unsure, say Y.
384
385config SMP
386	bool "Symmetric multi-processing support"
387	---help---
388	  This enables support for systems with more than one CPU. If you have
389	  a system with only one CPU, say N. If you have a system with more
390	  than one CPU, say Y.
391
392	  If you say N here, the kernel will run on uni- and multiprocessor
393	  machines, but will use only one CPU of a multiprocessor machine. If
394	  you say Y here, the kernel will run on many, but not all,
395	  uniprocessor machines. On a uniprocessor machine, the kernel
396	  will run faster if you say N here.
397
398	  Note that if you say Y here and choose architecture "586" or
399	  "Pentium" under "Processor family", the kernel will not work on 486
400	  architectures. Similarly, multiprocessor kernels for the "PPro"
401	  architecture may not work on all Pentium based boards.
402
403	  People using multiprocessor machines who say Y here should also say
404	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
405	  Management" code will be disabled if you say Y here.
406
407	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
408	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
409	  <http://www.tldp.org/docs.html#howto>.
410
411	  If you don't know what to do here, say N.
412
413config X86_FEATURE_NAMES
414	bool "Processor feature human-readable names" if EMBEDDED
415	default y
416	---help---
417	  This option compiles in a table of x86 feature bits and corresponding
418	  names.  This is required to support /proc/cpuinfo and a few kernel
419	  messages.  You can disable this to save space, at the expense of
420	  making those few kernel messages show numeric feature bits instead.
421
422	  If in doubt, say Y.
423
424config X86_X2APIC
425	bool "Support x2apic"
426	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
427	---help---
428	  This enables x2apic support on CPUs that have this feature.
429
430	  This allows 32-bit apic IDs (so it can support very large systems),
431	  and accesses the local apic via MSRs not via mmio.
432
433	  If you don't know what to do here, say N.
434
435config X86_MPPARSE
436	bool "Enable MPS table" if ACPI || SFI
437	default y
438	depends on X86_LOCAL_APIC
439	---help---
440	  For old smp systems that do not have proper acpi support. Newer systems
441	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
442
443config GOLDFISH
444	def_bool y
445	depends on X86_GOLDFISH
446
447config RETPOLINE
448	bool "Avoid speculative indirect branches in kernel"
449	default y
450	select STACK_VALIDATION if HAVE_STACK_VALIDATION
451	help
452	  Compile kernel with the retpoline compiler options to guard against
453	  kernel-to-user data leaks by avoiding speculative indirect
454	  branches. Requires a compiler with -mindirect-branch=thunk-extern
455	  support for full protection. The kernel may run slower.
456
457config X86_CPU_RESCTRL
458	bool "x86 CPU resource control support"
459	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
460	select KERNFS
461	select PROC_CPU_RESCTRL		if PROC_FS
462	help
463	  Enable x86 CPU resource control support.
464
465	  Provide support for the allocation and monitoring of system resources
466	  usage by the CPU.
467
468	  Intel calls this Intel Resource Director Technology
469	  (Intel(R) RDT). More information about RDT can be found in the
470	  Intel x86 Architecture Software Developer Manual.
471
472	  AMD calls this AMD Platform Quality of Service (AMD QoS).
473	  More information about AMD QoS can be found in the AMD64 Technology
474	  Platform Quality of Service Extensions manual.
475
476	  Say N if unsure.
477
478if X86_32
479config X86_BIGSMP
480	bool "Support for big SMP systems with more than 8 CPUs"
481	depends on SMP
482	---help---
483	  This option is needed for the systems that have more than 8 CPUs.
484
485config X86_EXTENDED_PLATFORM
486	bool "Support for extended (non-PC) x86 platforms"
487	default y
488	---help---
489	  If you disable this option then the kernel will only support
490	  standard PC platforms. (which covers the vast majority of
491	  systems out there.)
492
493	  If you enable this option then you'll be able to select support
494	  for the following (non-PC) 32 bit x86 platforms:
495		Goldfish (Android emulator)
496		AMD Elan
497		RDC R-321x SoC
498		SGI 320/540 (Visual Workstation)
499		STA2X11-based (e.g. Northville)
500		Moorestown MID devices
501
502	  If you have one of these systems, or if you want to build a
503	  generic distribution kernel, say Y here - otherwise say N.
504endif
505
506if X86_64
507config X86_EXTENDED_PLATFORM
508	bool "Support for extended (non-PC) x86 platforms"
509	default y
510	---help---
511	  If you disable this option then the kernel will only support
512	  standard PC platforms. (which covers the vast majority of
513	  systems out there.)
514
515	  If you enable this option then you'll be able to select support
516	  for the following (non-PC) 64 bit x86 platforms:
517		Numascale NumaChip
518		ScaleMP vSMP
519		SGI Ultraviolet
520
521	  If you have one of these systems, or if you want to build a
522	  generic distribution kernel, say Y here - otherwise say N.
523endif
524# This is an alphabetically sorted list of 64 bit extended platforms
525# Please maintain the alphabetic order if and when there are additions
526config X86_NUMACHIP
527	bool "Numascale NumaChip"
528	depends on X86_64
529	depends on X86_EXTENDED_PLATFORM
530	depends on NUMA
531	depends on SMP
532	depends on X86_X2APIC
533	depends on PCI_MMCONFIG
534	---help---
535	  Adds support for Numascale NumaChip large-SMP systems. Needed to
536	  enable more than ~168 cores.
537	  If you don't have one of these, you should say N here.
538
539config X86_VSMP
540	bool "ScaleMP vSMP"
541	select HYPERVISOR_GUEST
542	select PARAVIRT
543	depends on X86_64 && PCI
544	depends on X86_EXTENDED_PLATFORM
545	depends on SMP
546	---help---
547	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
548	  supposed to run on these EM64T-based machines.  Only choose this option
549	  if you have one of these machines.
550
551config X86_UV
552	bool "SGI Ultraviolet"
553	depends on X86_64
554	depends on X86_EXTENDED_PLATFORM
555	depends on NUMA
556	depends on EFI
557	depends on X86_X2APIC
558	depends on PCI
559	---help---
560	  This option is needed in order to support SGI Ultraviolet systems.
561	  If you don't have one of these, you should say N here.
562
563# Following is an alphabetically sorted list of 32 bit extended platforms
564# Please maintain the alphabetic order if and when there are additions
565
566config X86_GOLDFISH
567	bool "Goldfish (Virtual Platform)"
568	depends on X86_EXTENDED_PLATFORM
569	---help---
570	 Enable support for the Goldfish virtual platform used primarily
571	 for Android development. Unless you are building for the Android
572	 Goldfish emulator say N here.
573
574config X86_INTEL_CE
575	bool "CE4100 TV platform"
576	depends on PCI
577	depends on PCI_GODIRECT
578	depends on X86_IO_APIC
579	depends on X86_32
580	depends on X86_EXTENDED_PLATFORM
581	select X86_REBOOTFIXUPS
582	select OF
583	select OF_EARLY_FLATTREE
584	---help---
585	  Select for the Intel CE media processor (CE4100) SOC.
586	  This option compiles in support for the CE4100 SOC for settop
587	  boxes and media devices.
588
589config X86_INTEL_MID
590	bool "Intel MID platform support"
591	depends on X86_EXTENDED_PLATFORM
592	depends on X86_PLATFORM_DEVICES
593	depends on PCI
594	depends on X86_64 || (PCI_GOANY && X86_32)
595	depends on X86_IO_APIC
596	select SFI
597	select I2C
598	select DW_APB_TIMER
599	select APB_TIMER
600	select INTEL_SCU_IPC
601	select MFD_INTEL_MSIC
602	---help---
603	  Select to build a kernel capable of supporting Intel MID (Mobile
604	  Internet Device) platform systems which do not have the PCI legacy
605	  interfaces. If you are building for a PC class system say N here.
606
607	  Intel MID platforms are based on an Intel processor and chipset which
608	  consume less power than most of the x86 derivatives.
609
610config X86_INTEL_QUARK
611	bool "Intel Quark platform support"
612	depends on X86_32
613	depends on X86_EXTENDED_PLATFORM
614	depends on X86_PLATFORM_DEVICES
615	depends on X86_TSC
616	depends on PCI
617	depends on PCI_GOANY
618	depends on X86_IO_APIC
619	select IOSF_MBI
620	select INTEL_IMR
621	select COMMON_CLK
622	---help---
623	  Select to include support for Quark X1000 SoC.
624	  Say Y here if you have a Quark based system such as the Arduino
625	  compatible Intel Galileo.
626
627config X86_INTEL_LPSS
628	bool "Intel Low Power Subsystem Support"
629	depends on X86 && ACPI && PCI
630	select COMMON_CLK
631	select PINCTRL
632	select IOSF_MBI
633	---help---
634	  Select to build support for Intel Low Power Subsystem such as
635	  found on Intel Lynxpoint PCH. Selecting this option enables
636	  things like clock tree (common clock framework) and pincontrol
637	  which are needed by the LPSS peripheral drivers.
638
639config X86_AMD_PLATFORM_DEVICE
640	bool "AMD ACPI2Platform devices support"
641	depends on ACPI
642	select COMMON_CLK
643	select PINCTRL
644	---help---
645	  Select to interpret AMD specific ACPI device to platform device
646	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
647	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
648	  implemented under PINCTRL subsystem.
649
650config IOSF_MBI
651	tristate "Intel SoC IOSF Sideband support for SoC platforms"
652	depends on PCI
653	---help---
654	  This option enables sideband register access support for Intel SoC
655	  platforms. On these platforms the IOSF sideband is used in lieu of
656	  MSR's for some register accesses, mostly but not limited to thermal
657	  and power. Drivers may query the availability of this device to
658	  determine if they need the sideband in order to work on these
659	  platforms. The sideband is available on the following SoC products.
660	  This list is not meant to be exclusive.
661	   - BayTrail
662	   - Braswell
663	   - Quark
664
665	  You should say Y if you are running a kernel on one of these SoC's.
666
667config IOSF_MBI_DEBUG
668	bool "Enable IOSF sideband access through debugfs"
669	depends on IOSF_MBI && DEBUG_FS
670	---help---
671	  Select this option to expose the IOSF sideband access registers (MCR,
672	  MDR, MCRX) through debugfs to write and read register information from
673	  different units on the SoC. This is most useful for obtaining device
674	  state information for debug and analysis. As this is a general access
675	  mechanism, users of this option would have specific knowledge of the
676	  device they want to access.
677
678	  If you don't require the option or are in doubt, say N.
679
680config X86_RDC321X
681	bool "RDC R-321x SoC"
682	depends on X86_32
683	depends on X86_EXTENDED_PLATFORM
684	select M486
685	select X86_REBOOTFIXUPS
686	---help---
687	  This option is needed for RDC R-321x system-on-chip, also known
688	  as R-8610-(G).
689	  If you don't have one of these chips, you should say N here.
690
691config X86_32_NON_STANDARD
692	bool "Support non-standard 32-bit SMP architectures"
693	depends on X86_32 && SMP
694	depends on X86_EXTENDED_PLATFORM
695	---help---
696	  This option compiles in the bigsmp and STA2X11 default
697	  subarchitectures.  It is intended for a generic binary
698	  kernel. If you select them all, kernel will probe it one by
699	  one and will fallback to default.
700
701# Alphabetically sorted list of Non standard 32 bit platforms
702
703config X86_SUPPORTS_MEMORY_FAILURE
704	def_bool y
705	# MCE code calls memory_failure():
706	depends on X86_MCE
707	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
708	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
709	depends on X86_64 || !SPARSEMEM
710	select ARCH_SUPPORTS_MEMORY_FAILURE
711
712config STA2X11
713	bool "STA2X11 Companion Chip Support"
714	depends on X86_32_NON_STANDARD && PCI
715	select SWIOTLB
716	select MFD_STA2X11
717	select GPIOLIB
718	---help---
719	  This adds support for boards based on the STA2X11 IO-Hub,
720	  a.k.a. "ConneXt". The chip is used in place of the standard
721	  PC chipset, so all "standard" peripherals are missing. If this
722	  option is selected the kernel will still be able to boot on
723	  standard PC machines.
724
725config X86_32_IRIS
726	tristate "Eurobraille/Iris poweroff module"
727	depends on X86_32
728	---help---
729	  The Iris machines from EuroBraille do not have APM or ACPI support
730	  to shut themselves down properly.  A special I/O sequence is
731	  needed to do so, which is what this module does at
732	  kernel shutdown.
733
734	  This is only for Iris machines from EuroBraille.
735
736	  If unused, say N.
737
738config SCHED_OMIT_FRAME_POINTER
739	def_bool y
740	prompt "Single-depth WCHAN output"
741	depends on X86
742	---help---
743	  Calculate simpler /proc/<PID>/wchan values. If this option
744	  is disabled then wchan values will recurse back to the
745	  caller function. This provides more accurate wchan values,
746	  at the expense of slightly more scheduling overhead.
747
748	  If in doubt, say "Y".
749
750menuconfig HYPERVISOR_GUEST
751	bool "Linux guest support"
752	---help---
753	  Say Y here to enable options for running Linux under various hyper-
754	  visors. This option enables basic hypervisor detection and platform
755	  setup.
756
757	  If you say N, all options in this submenu will be skipped and
758	  disabled, and Linux guest support won't be built in.
759
760if HYPERVISOR_GUEST
761
762config PARAVIRT
763	bool "Enable paravirtualization code"
764	---help---
765	  This changes the kernel so it can modify itself when it is run
766	  under a hypervisor, potentially improving performance significantly
767	  over full virtualization.  However, when run without a hypervisor
768	  the kernel is theoretically slower and slightly larger.
769
770config PARAVIRT_XXL
771	bool
772
773config PARAVIRT_DEBUG
774	bool "paravirt-ops debugging"
775	depends on PARAVIRT && DEBUG_KERNEL
776	---help---
777	  Enable to debug paravirt_ops internals.  Specifically, BUG if
778	  a paravirt_op is missing when it is called.
779
780config PARAVIRT_SPINLOCKS
781	bool "Paravirtualization layer for spinlocks"
782	depends on PARAVIRT && SMP
783	---help---
784	  Paravirtualized spinlocks allow a pvops backend to replace the
785	  spinlock implementation with something virtualization-friendly
786	  (for example, block the virtual CPU rather than spinning).
787
788	  It has a minimal impact on native kernels and gives a nice performance
789	  benefit on paravirtualized KVM / Xen kernels.
790
791	  If you are unsure how to answer this question, answer Y.
792
793config X86_HV_CALLBACK_VECTOR
794	def_bool n
795
796source "arch/x86/xen/Kconfig"
797
798config KVM_GUEST
799	bool "KVM Guest support (including kvmclock)"
800	depends on PARAVIRT
801	select PARAVIRT_CLOCK
802	select ARCH_CPUIDLE_HALTPOLL
803	default y
804	---help---
805	  This option enables various optimizations for running under the KVM
806	  hypervisor. It includes a paravirtualized clock, so that instead
807	  of relying on a PIT (or probably other) emulation by the
808	  underlying device model, the host provides the guest with
809	  timing infrastructure such as time of day, and system time
810
811config ARCH_CPUIDLE_HALTPOLL
812	def_bool n
813	prompt "Disable host haltpoll when loading haltpoll driver"
814	help
815	  If virtualized under KVM, disable host haltpoll.
816
817config PVH
818	bool "Support for running PVH guests"
819	---help---
820	  This option enables the PVH entry point for guest virtual machines
821	  as specified in the x86/HVM direct boot ABI.
822
823config KVM_DEBUG_FS
824	bool "Enable debug information for KVM Guests in debugfs"
825	depends on KVM_GUEST && DEBUG_FS
826	---help---
827	  This option enables collection of various statistics for KVM guest.
828	  Statistics are displayed in debugfs filesystem. Enabling this option
829	  may incur significant overhead.
830
831config PARAVIRT_TIME_ACCOUNTING
832	bool "Paravirtual steal time accounting"
833	depends on PARAVIRT
834	---help---
835	  Select this option to enable fine granularity task steal time
836	  accounting. Time spent executing other tasks in parallel with
837	  the current vCPU is discounted from the vCPU power. To account for
838	  that, there can be a small performance impact.
839
840	  If in doubt, say N here.
841
842config PARAVIRT_CLOCK
843	bool
844
845config JAILHOUSE_GUEST
846	bool "Jailhouse non-root cell support"
847	depends on X86_64 && PCI
848	select X86_PM_TIMER
849	---help---
850	  This option allows to run Linux as guest in a Jailhouse non-root
851	  cell. You can leave this option disabled if you only want to start
852	  Jailhouse and run Linux afterwards in the root cell.
853
854config ACRN_GUEST
855	bool "ACRN Guest support"
856	depends on X86_64
857	select X86_HV_CALLBACK_VECTOR
858	help
859	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
860	  a flexible, lightweight reference open-source hypervisor, built with
861	  real-time and safety-criticality in mind. It is built for embedded
862	  IOT with small footprint and real-time features. More details can be
863	  found in https://projectacrn.org/.
864
865endif #HYPERVISOR_GUEST
866
867source "arch/x86/Kconfig.cpu"
868
869config HPET_TIMER
870	def_bool X86_64
871	prompt "HPET Timer Support" if X86_32
872	---help---
873	  Use the IA-PC HPET (High Precision Event Timer) to manage
874	  time in preference to the PIT and RTC, if a HPET is
875	  present.
876	  HPET is the next generation timer replacing legacy 8254s.
877	  The HPET provides a stable time base on SMP
878	  systems, unlike the TSC, but it is more expensive to access,
879	  as it is off-chip.  The interface used is documented
880	  in the HPET spec, revision 1.
881
882	  You can safely choose Y here.  However, HPET will only be
883	  activated if the platform and the BIOS support this feature.
884	  Otherwise the 8254 will be used for timing services.
885
886	  Choose N to continue using the legacy 8254 timer.
887
888config HPET_EMULATE_RTC
889	def_bool y
890	depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
891
892config APB_TIMER
893	def_bool y if X86_INTEL_MID
894	prompt "Intel MID APB Timer Support" if X86_INTEL_MID
895	select DW_APB_TIMER
896	depends on X86_INTEL_MID && SFI
897	help
898	 APB timer is the replacement for 8254, HPET on X86 MID platforms.
899	 The APBT provides a stable time base on SMP
900	 systems, unlike the TSC, but it is more expensive to access,
901	 as it is off-chip. APB timers are always running regardless of CPU
902	 C states, they are used as per CPU clockevent device when possible.
903
904# Mark as expert because too many people got it wrong.
905# The code disables itself when not needed.
906config DMI
907	default y
908	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
909	bool "Enable DMI scanning" if EXPERT
910	---help---
911	  Enabled scanning of DMI to identify machine quirks. Say Y
912	  here unless you have verified that your setup is not
913	  affected by entries in the DMI blacklist. Required by PNP
914	  BIOS code.
915
916config GART_IOMMU
917	bool "Old AMD GART IOMMU support"
918	select IOMMU_HELPER
919	select SWIOTLB
920	depends on X86_64 && PCI && AMD_NB
921	---help---
922	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
923	  GART based hardware IOMMUs.
924
925	  The GART supports full DMA access for devices with 32-bit access
926	  limitations, on systems with more than 3 GB. This is usually needed
927	  for USB, sound, many IDE/SATA chipsets and some other devices.
928
929	  Newer systems typically have a modern AMD IOMMU, supported via
930	  the CONFIG_AMD_IOMMU=y config option.
931
932	  In normal configurations this driver is only active when needed:
933	  there's more than 3 GB of memory and the system contains a
934	  32-bit limited device.
935
936	  If unsure, say Y.
937
938config MAXSMP
939	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
940	depends on X86_64 && SMP && DEBUG_KERNEL
941	select CPUMASK_OFFSTACK
942	---help---
943	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
944	  If unsure, say N.
945
946#
947# The maximum number of CPUs supported:
948#
949# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
950# and which can be configured interactively in the
951# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
952#
953# The ranges are different on 32-bit and 64-bit kernels, depending on
954# hardware capabilities and scalability features of the kernel.
955#
956# ( If MAXSMP is enabled we just use the highest possible value and disable
957#   interactive configuration. )
958#
959
960config NR_CPUS_RANGE_BEGIN
961	int
962	default NR_CPUS_RANGE_END if MAXSMP
963	default    1 if !SMP
964	default    2
965
966config NR_CPUS_RANGE_END
967	int
968	depends on X86_32
969	default   64 if  SMP &&  X86_BIGSMP
970	default    8 if  SMP && !X86_BIGSMP
971	default    1 if !SMP
972
973config NR_CPUS_RANGE_END
974	int
975	depends on X86_64
976	default 8192 if  SMP && CPUMASK_OFFSTACK
977	default  512 if  SMP && !CPUMASK_OFFSTACK
978	default    1 if !SMP
979
980config NR_CPUS_DEFAULT
981	int
982	depends on X86_32
983	default   32 if  X86_BIGSMP
984	default    8 if  SMP
985	default    1 if !SMP
986
987config NR_CPUS_DEFAULT
988	int
989	depends on X86_64
990	default 8192 if  MAXSMP
991	default   64 if  SMP
992	default    1 if !SMP
993
994config NR_CPUS
995	int "Maximum number of CPUs" if SMP && !MAXSMP
996	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
997	default NR_CPUS_DEFAULT
998	---help---
999	  This allows you to specify the maximum number of CPUs which this
1000	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1001	  supported value is 8192, otherwise the maximum value is 512.  The
1002	  minimum value which makes sense is 2.
1003
1004	  This is purely to save memory: each supported CPU adds about 8KB
1005	  to the kernel image.
1006
1007config SCHED_SMT
1008	def_bool y if SMP
1009
1010config SCHED_MC
1011	def_bool y
1012	prompt "Multi-core scheduler support"
1013	depends on SMP
1014	---help---
1015	  Multi-core scheduler support improves the CPU scheduler's decision
1016	  making when dealing with multi-core CPU chips at a cost of slightly
1017	  increased overhead in some places. If unsure say N here.
1018
1019config SCHED_MC_PRIO
1020	bool "CPU core priorities scheduler support"
1021	depends on SCHED_MC && CPU_SUP_INTEL
1022	select X86_INTEL_PSTATE
1023	select CPU_FREQ
1024	default y
1025	---help---
1026	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1027	  core ordering determined at manufacturing time, which allows
1028	  certain cores to reach higher turbo frequencies (when running
1029	  single threaded workloads) than others.
1030
1031	  Enabling this kernel feature teaches the scheduler about
1032	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1033	  scheduler's CPU selection logic accordingly, so that higher
1034	  overall system performance can be achieved.
1035
1036	  This feature will have no effect on CPUs without this feature.
1037
1038	  If unsure say Y here.
1039
1040config UP_LATE_INIT
1041	def_bool y
1042	depends on !SMP && X86_LOCAL_APIC
1043
1044config X86_UP_APIC
1045	bool "Local APIC support on uniprocessors" if !PCI_MSI
1046	default PCI_MSI
1047	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1048	---help---
1049	  A local APIC (Advanced Programmable Interrupt Controller) is an
1050	  integrated interrupt controller in the CPU. If you have a single-CPU
1051	  system which has a processor with a local APIC, you can say Y here to
1052	  enable and use it. If you say Y here even though your machine doesn't
1053	  have a local APIC, then the kernel will still run with no slowdown at
1054	  all. The local APIC supports CPU-generated self-interrupts (timer,
1055	  performance counters), and the NMI watchdog which detects hard
1056	  lockups.
1057
1058config X86_UP_IOAPIC
1059	bool "IO-APIC support on uniprocessors"
1060	depends on X86_UP_APIC
1061	---help---
1062	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1063	  SMP-capable replacement for PC-style interrupt controllers. Most
1064	  SMP systems and many recent uniprocessor systems have one.
1065
1066	  If you have a single-CPU system with an IO-APIC, you can say Y here
1067	  to use it. If you say Y here even though your machine doesn't have
1068	  an IO-APIC, then the kernel will still run with no slowdown at all.
1069
1070config X86_LOCAL_APIC
1071	def_bool y
1072	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1073	select IRQ_DOMAIN_HIERARCHY
1074	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1075
1076config X86_IO_APIC
1077	def_bool y
1078	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1079
1080config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1081	bool "Reroute for broken boot IRQs"
1082	depends on X86_IO_APIC
1083	---help---
1084	  This option enables a workaround that fixes a source of
1085	  spurious interrupts. This is recommended when threaded
1086	  interrupt handling is used on systems where the generation of
1087	  superfluous "boot interrupts" cannot be disabled.
1088
1089	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1090	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1091	  kernel does during interrupt handling). On chipsets where this
1092	  boot IRQ generation cannot be disabled, this workaround keeps
1093	  the original IRQ line masked so that only the equivalent "boot
1094	  IRQ" is delivered to the CPUs. The workaround also tells the
1095	  kernel to set up the IRQ handler on the boot IRQ line. In this
1096	  way only one interrupt is delivered to the kernel. Otherwise
1097	  the spurious second interrupt may cause the kernel to bring
1098	  down (vital) interrupt lines.
1099
1100	  Only affects "broken" chipsets. Interrupt sharing may be
1101	  increased on these systems.
1102
1103config X86_MCE
1104	bool "Machine Check / overheating reporting"
1105	select GENERIC_ALLOCATOR
1106	default y
1107	---help---
1108	  Machine Check support allows the processor to notify the
1109	  kernel if it detects a problem (e.g. overheating, data corruption).
1110	  The action the kernel takes depends on the severity of the problem,
1111	  ranging from warning messages to halting the machine.
1112
1113config X86_MCELOG_LEGACY
1114	bool "Support for deprecated /dev/mcelog character device"
1115	depends on X86_MCE
1116	---help---
1117	  Enable support for /dev/mcelog which is needed by the old mcelog
1118	  userspace logging daemon. Consider switching to the new generation
1119	  rasdaemon solution.
1120
1121config X86_MCE_INTEL
1122	def_bool y
1123	prompt "Intel MCE features"
1124	depends on X86_MCE && X86_LOCAL_APIC
1125	---help---
1126	   Additional support for intel specific MCE features such as
1127	   the thermal monitor.
1128
1129config X86_MCE_AMD
1130	def_bool y
1131	prompt "AMD MCE features"
1132	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1133	---help---
1134	   Additional support for AMD specific MCE features such as
1135	   the DRAM Error Threshold.
1136
1137config X86_ANCIENT_MCE
1138	bool "Support for old Pentium 5 / WinChip machine checks"
1139	depends on X86_32 && X86_MCE
1140	---help---
1141	  Include support for machine check handling on old Pentium 5 or WinChip
1142	  systems. These typically need to be enabled explicitly on the command
1143	  line.
1144
1145config X86_MCE_THRESHOLD
1146	depends on X86_MCE_AMD || X86_MCE_INTEL
1147	def_bool y
1148
1149config X86_MCE_INJECT
1150	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1151	tristate "Machine check injector support"
1152	---help---
1153	  Provide support for injecting machine checks for testing purposes.
1154	  If you don't know what a machine check is and you don't do kernel
1155	  QA it is safe to say n.
1156
1157config X86_THERMAL_VECTOR
1158	def_bool y
1159	depends on X86_MCE_INTEL
1160
1161source "arch/x86/events/Kconfig"
1162
1163config X86_LEGACY_VM86
1164	bool "Legacy VM86 support"
1165	depends on X86_32
1166	---help---
1167	  This option allows user programs to put the CPU into V8086
1168	  mode, which is an 80286-era approximation of 16-bit real mode.
1169
1170	  Some very old versions of X and/or vbetool require this option
1171	  for user mode setting.  Similarly, DOSEMU will use it if
1172	  available to accelerate real mode DOS programs.  However, any
1173	  recent version of DOSEMU, X, or vbetool should be fully
1174	  functional even without kernel VM86 support, as they will all
1175	  fall back to software emulation. Nevertheless, if you are using
1176	  a 16-bit DOS program where 16-bit performance matters, vm86
1177	  mode might be faster than emulation and you might want to
1178	  enable this option.
1179
1180	  Note that any app that works on a 64-bit kernel is unlikely to
1181	  need this option, as 64-bit kernels don't, and can't, support
1182	  V8086 mode. This option is also unrelated to 16-bit protected
1183	  mode and is not needed to run most 16-bit programs under Wine.
1184
1185	  Enabling this option increases the complexity of the kernel
1186	  and slows down exception handling a tiny bit.
1187
1188	  If unsure, say N here.
1189
1190config VM86
1191	bool
1192	default X86_LEGACY_VM86
1193
1194config X86_16BIT
1195	bool "Enable support for 16-bit segments" if EXPERT
1196	default y
1197	depends on MODIFY_LDT_SYSCALL
1198	---help---
1199	  This option is required by programs like Wine to run 16-bit
1200	  protected mode legacy code on x86 processors.  Disabling
1201	  this option saves about 300 bytes on i386, or around 6K text
1202	  plus 16K runtime memory on x86-64,
1203
1204config X86_ESPFIX32
1205	def_bool y
1206	depends on X86_16BIT && X86_32
1207
1208config X86_ESPFIX64
1209	def_bool y
1210	depends on X86_16BIT && X86_64
1211
1212config X86_VSYSCALL_EMULATION
1213	bool "Enable vsyscall emulation" if EXPERT
1214	default y
1215	depends on X86_64
1216	---help---
1217	 This enables emulation of the legacy vsyscall page.  Disabling
1218	 it is roughly equivalent to booting with vsyscall=none, except
1219	 that it will also disable the helpful warning if a program
1220	 tries to use a vsyscall.  With this option set to N, offending
1221	 programs will just segfault, citing addresses of the form
1222	 0xffffffffff600?00.
1223
1224	 This option is required by many programs built before 2013, and
1225	 care should be used even with newer programs if set to N.
1226
1227	 Disabling this option saves about 7K of kernel size and
1228	 possibly 4K of additional runtime pagetable memory.
1229
1230config X86_IOPL_IOPERM
1231	bool "IOPERM and IOPL Emulation"
1232	default y
1233	---help---
1234	  This enables the ioperm() and iopl() syscalls which are necessary
1235	  for legacy applications.
1236
1237	  Legacy IOPL support is an overbroad mechanism which allows user
1238	  space aside of accessing all 65536 I/O ports also to disable
1239	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1240	  capabilities and permission from potentially active security
1241	  modules.
1242
1243	  The emulation restricts the functionality of the syscall to
1244	  only allowing the full range I/O port access, but prevents the
1245	  ability to disable interrupts from user space which would be
1246	  granted if the hardware IOPL mechanism would be used.
1247
1248config TOSHIBA
1249	tristate "Toshiba Laptop support"
1250	depends on X86_32
1251	---help---
1252	  This adds a driver to safely access the System Management Mode of
1253	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1254	  not work on models with a Phoenix BIOS. The System Management Mode
1255	  is used to set the BIOS and power saving options on Toshiba portables.
1256
1257	  For information on utilities to make use of this driver see the
1258	  Toshiba Linux utilities web site at:
1259	  <http://www.buzzard.org.uk/toshiba/>.
1260
1261	  Say Y if you intend to run this kernel on a Toshiba portable.
1262	  Say N otherwise.
1263
1264config I8K
1265	tristate "Dell i8k legacy laptop support"
1266	select HWMON
1267	select SENSORS_DELL_SMM
1268	---help---
1269	  This option enables legacy /proc/i8k userspace interface in hwmon
1270	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1271	  temperature and allows controlling fan speeds of Dell laptops via
1272	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1273	  it reports also power and hotkey status. For fan speed control is
1274	  needed userspace package i8kutils.
1275
1276	  Say Y if you intend to run this kernel on old Dell laptops or want to
1277	  use userspace package i8kutils.
1278	  Say N otherwise.
1279
1280config X86_REBOOTFIXUPS
1281	bool "Enable X86 board specific fixups for reboot"
1282	depends on X86_32
1283	---help---
1284	  This enables chipset and/or board specific fixups to be done
1285	  in order to get reboot to work correctly. This is only needed on
1286	  some combinations of hardware and BIOS. The symptom, for which
1287	  this config is intended, is when reboot ends with a stalled/hung
1288	  system.
1289
1290	  Currently, the only fixup is for the Geode machines using
1291	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1292
1293	  Say Y if you want to enable the fixup. Currently, it's safe to
1294	  enable this option even if you don't need it.
1295	  Say N otherwise.
1296
1297config MICROCODE
1298	bool "CPU microcode loading support"
1299	default y
1300	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1301	select FW_LOADER
1302	---help---
1303	  If you say Y here, you will be able to update the microcode on
1304	  Intel and AMD processors. The Intel support is for the IA32 family,
1305	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1306	  AMD support is for families 0x10 and later. You will obviously need
1307	  the actual microcode binary data itself which is not shipped with
1308	  the Linux kernel.
1309
1310	  The preferred method to load microcode from a detached initrd is described
1311	  in Documentation/x86/microcode.rst. For that you need to enable
1312	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1313	  initrd for microcode blobs.
1314
1315	  In addition, you can build the microcode into the kernel. For that you
1316	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1317	  config option.
1318
1319config MICROCODE_INTEL
1320	bool "Intel microcode loading support"
1321	depends on MICROCODE
1322	default MICROCODE
1323	select FW_LOADER
1324	---help---
1325	  This options enables microcode patch loading support for Intel
1326	  processors.
1327
1328	  For the current Intel microcode data package go to
1329	  <https://downloadcenter.intel.com> and search for
1330	  'Linux Processor Microcode Data File'.
1331
1332config MICROCODE_AMD
1333	bool "AMD microcode loading support"
1334	depends on MICROCODE
1335	select FW_LOADER
1336	---help---
1337	  If you select this option, microcode patch loading support for AMD
1338	  processors will be enabled.
1339
1340config MICROCODE_OLD_INTERFACE
1341	bool "Ancient loading interface (DEPRECATED)"
1342	default n
1343	depends on MICROCODE
1344	---help---
1345	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1346	  which was used by userspace tools like iucode_tool and microcode.ctl.
1347	  It is inadequate because it runs too late to be able to properly
1348	  load microcode on a machine and it needs special tools. Instead, you
1349	  should've switched to the early loading method with the initrd or
1350	  builtin microcode by now: Documentation/x86/microcode.rst
1351
1352config X86_MSR
1353	tristate "/dev/cpu/*/msr - Model-specific register support"
1354	---help---
1355	  This device gives privileged processes access to the x86
1356	  Model-Specific Registers (MSRs).  It is a character device with
1357	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1358	  MSR accesses are directed to a specific CPU on multi-processor
1359	  systems.
1360
1361config X86_CPUID
1362	tristate "/dev/cpu/*/cpuid - CPU information support"
1363	---help---
1364	  This device gives processes access to the x86 CPUID instruction to
1365	  be executed on a specific processor.  It is a character device
1366	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1367	  /dev/cpu/31/cpuid.
1368
1369choice
1370	prompt "High Memory Support"
1371	default HIGHMEM4G
1372	depends on X86_32
1373
1374config NOHIGHMEM
1375	bool "off"
1376	---help---
1377	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1378	  However, the address space of 32-bit x86 processors is only 4
1379	  Gigabytes large. That means that, if you have a large amount of
1380	  physical memory, not all of it can be "permanently mapped" by the
1381	  kernel. The physical memory that's not permanently mapped is called
1382	  "high memory".
1383
1384	  If you are compiling a kernel which will never run on a machine with
1385	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1386	  choice and suitable for most users). This will result in a "3GB/1GB"
1387	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1388	  space and the remaining part of the 4GB virtual memory space is used
1389	  by the kernel to permanently map as much physical memory as
1390	  possible.
1391
1392	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1393	  answer "4GB" here.
1394
1395	  If more than 4 Gigabytes is used then answer "64GB" here. This
1396	  selection turns Intel PAE (Physical Address Extension) mode on.
1397	  PAE implements 3-level paging on IA32 processors. PAE is fully
1398	  supported by Linux, PAE mode is implemented on all recent Intel
1399	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1400	  then the kernel will not boot on CPUs that don't support PAE!
1401
1402	  The actual amount of total physical memory will either be
1403	  auto detected or can be forced by using a kernel command line option
1404	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1405	  your boot loader (lilo or loadlin) about how to pass options to the
1406	  kernel at boot time.)
1407
1408	  If unsure, say "off".
1409
1410config HIGHMEM4G
1411	bool "4GB"
1412	---help---
1413	  Select this if you have a 32-bit processor and between 1 and 4
1414	  gigabytes of physical RAM.
1415
1416config HIGHMEM64G
1417	bool "64GB"
1418	depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1419	select X86_PAE
1420	---help---
1421	  Select this if you have a 32-bit processor and more than 4
1422	  gigabytes of physical RAM.
1423
1424endchoice
1425
1426choice
1427	prompt "Memory split" if EXPERT
1428	default VMSPLIT_3G
1429	depends on X86_32
1430	---help---
1431	  Select the desired split between kernel and user memory.
1432
1433	  If the address range available to the kernel is less than the
1434	  physical memory installed, the remaining memory will be available
1435	  as "high memory". Accessing high memory is a little more costly
1436	  than low memory, as it needs to be mapped into the kernel first.
1437	  Note that increasing the kernel address space limits the range
1438	  available to user programs, making the address space there
1439	  tighter.  Selecting anything other than the default 3G/1G split
1440	  will also likely make your kernel incompatible with binary-only
1441	  kernel modules.
1442
1443	  If you are not absolutely sure what you are doing, leave this
1444	  option alone!
1445
1446	config VMSPLIT_3G
1447		bool "3G/1G user/kernel split"
1448	config VMSPLIT_3G_OPT
1449		depends on !X86_PAE
1450		bool "3G/1G user/kernel split (for full 1G low memory)"
1451	config VMSPLIT_2G
1452		bool "2G/2G user/kernel split"
1453	config VMSPLIT_2G_OPT
1454		depends on !X86_PAE
1455		bool "2G/2G user/kernel split (for full 2G low memory)"
1456	config VMSPLIT_1G
1457		bool "1G/3G user/kernel split"
1458endchoice
1459
1460config PAGE_OFFSET
1461	hex
1462	default 0xB0000000 if VMSPLIT_3G_OPT
1463	default 0x80000000 if VMSPLIT_2G
1464	default 0x78000000 if VMSPLIT_2G_OPT
1465	default 0x40000000 if VMSPLIT_1G
1466	default 0xC0000000
1467	depends on X86_32
1468
1469config HIGHMEM
1470	def_bool y
1471	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1472
1473config X86_PAE
1474	bool "PAE (Physical Address Extension) Support"
1475	depends on X86_32 && !HIGHMEM4G
1476	select PHYS_ADDR_T_64BIT
1477	select SWIOTLB
1478	---help---
1479	  PAE is required for NX support, and furthermore enables
1480	  larger swapspace support for non-overcommit purposes. It
1481	  has the cost of more pagetable lookup overhead, and also
1482	  consumes more pagetable space per process.
1483
1484config X86_5LEVEL
1485	bool "Enable 5-level page tables support"
1486	default y
1487	select DYNAMIC_MEMORY_LAYOUT
1488	select SPARSEMEM_VMEMMAP
1489	depends on X86_64
1490	---help---
1491	  5-level paging enables access to larger address space:
1492	  upto 128 PiB of virtual address space and 4 PiB of
1493	  physical address space.
1494
1495	  It will be supported by future Intel CPUs.
1496
1497	  A kernel with the option enabled can be booted on machines that
1498	  support 4- or 5-level paging.
1499
1500	  See Documentation/x86/x86_64/5level-paging.rst for more
1501	  information.
1502
1503	  Say N if unsure.
1504
1505config X86_DIRECT_GBPAGES
1506	def_bool y
1507	depends on X86_64
1508	---help---
1509	  Certain kernel features effectively disable kernel
1510	  linear 1 GB mappings (even if the CPU otherwise
1511	  supports them), so don't confuse the user by printing
1512	  that we have them enabled.
1513
1514config X86_CPA_STATISTICS
1515	bool "Enable statistic for Change Page Attribute"
1516	depends on DEBUG_FS
1517	---help---
1518	  Expose statistics about the Change Page Attribute mechanism, which
1519	  helps to determine the effectiveness of preserving large and huge
1520	  page mappings when mapping protections are changed.
1521
1522config AMD_MEM_ENCRYPT
1523	bool "AMD Secure Memory Encryption (SME) support"
1524	depends on X86_64 && CPU_SUP_AMD
1525	select DYNAMIC_PHYSICAL_MASK
1526	select ARCH_USE_MEMREMAP_PROT
1527	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1528	---help---
1529	  Say yes to enable support for the encryption of system memory.
1530	  This requires an AMD processor that supports Secure Memory
1531	  Encryption (SME).
1532
1533config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1534	bool "Activate AMD Secure Memory Encryption (SME) by default"
1535	default y
1536	depends on AMD_MEM_ENCRYPT
1537	---help---
1538	  Say yes to have system memory encrypted by default if running on
1539	  an AMD processor that supports Secure Memory Encryption (SME).
1540
1541	  If set to Y, then the encryption of system memory can be
1542	  deactivated with the mem_encrypt=off command line option.
1543
1544	  If set to N, then the encryption of system memory can be
1545	  activated with the mem_encrypt=on command line option.
1546
1547# Common NUMA Features
1548config NUMA
1549	bool "NUMA Memory Allocation and Scheduler Support"
1550	depends on SMP
1551	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1552	default y if X86_BIGSMP
1553	---help---
1554	  Enable NUMA (Non-Uniform Memory Access) support.
1555
1556	  The kernel will try to allocate memory used by a CPU on the
1557	  local memory controller of the CPU and add some more
1558	  NUMA awareness to the kernel.
1559
1560	  For 64-bit this is recommended if the system is Intel Core i7
1561	  (or later), AMD Opteron, or EM64T NUMA.
1562
1563	  For 32-bit this is only needed if you boot a 32-bit
1564	  kernel on a 64-bit NUMA platform.
1565
1566	  Otherwise, you should say N.
1567
1568config AMD_NUMA
1569	def_bool y
1570	prompt "Old style AMD Opteron NUMA detection"
1571	depends on X86_64 && NUMA && PCI
1572	---help---
1573	  Enable AMD NUMA node topology detection.  You should say Y here if
1574	  you have a multi processor AMD system. This uses an old method to
1575	  read the NUMA configuration directly from the builtin Northbridge
1576	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1577	  which also takes priority if both are compiled in.
1578
1579config X86_64_ACPI_NUMA
1580	def_bool y
1581	prompt "ACPI NUMA detection"
1582	depends on X86_64 && NUMA && ACPI && PCI
1583	select ACPI_NUMA
1584	---help---
1585	  Enable ACPI SRAT based node topology detection.
1586
1587# Some NUMA nodes have memory ranges that span
1588# other nodes.  Even though a pfn is valid and
1589# between a node's start and end pfns, it may not
1590# reside on that node.  See memmap_init_zone()
1591# for details.
1592config NODES_SPAN_OTHER_NODES
1593	def_bool y
1594	depends on X86_64_ACPI_NUMA
1595
1596config NUMA_EMU
1597	bool "NUMA emulation"
1598	depends on NUMA
1599	---help---
1600	  Enable NUMA emulation. A flat machine will be split
1601	  into virtual nodes when booted with "numa=fake=N", where N is the
1602	  number of nodes. This is only useful for debugging.
1603
1604config NODES_SHIFT
1605	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1606	range 1 10
1607	default "10" if MAXSMP
1608	default "6" if X86_64
1609	default "3"
1610	depends on NEED_MULTIPLE_NODES
1611	---help---
1612	  Specify the maximum number of NUMA Nodes available on the target
1613	  system.  Increases memory reserved to accommodate various tables.
1614
1615config ARCH_HAVE_MEMORY_PRESENT
1616	def_bool y
1617	depends on X86_32 && DISCONTIGMEM
1618
1619config ARCH_FLATMEM_ENABLE
1620	def_bool y
1621	depends on X86_32 && !NUMA
1622
1623config ARCH_DISCONTIGMEM_ENABLE
1624	def_bool n
1625	depends on NUMA && X86_32
1626	depends on BROKEN
1627
1628config ARCH_SPARSEMEM_ENABLE
1629	def_bool y
1630	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1631	select SPARSEMEM_STATIC if X86_32
1632	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1633
1634config ARCH_SPARSEMEM_DEFAULT
1635	def_bool X86_64 || (NUMA && X86_32)
1636
1637config ARCH_SELECT_MEMORY_MODEL
1638	def_bool y
1639	depends on ARCH_SPARSEMEM_ENABLE
1640
1641config ARCH_MEMORY_PROBE
1642	bool "Enable sysfs memory/probe interface"
1643	depends on X86_64 && MEMORY_HOTPLUG
1644	help
1645	  This option enables a sysfs memory/probe interface for testing.
1646	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1647	  If you are unsure how to answer this question, answer N.
1648
1649config ARCH_PROC_KCORE_TEXT
1650	def_bool y
1651	depends on X86_64 && PROC_KCORE
1652
1653config ILLEGAL_POINTER_VALUE
1654	hex
1655	default 0 if X86_32
1656	default 0xdead000000000000 if X86_64
1657
1658config X86_PMEM_LEGACY_DEVICE
1659	bool
1660
1661config X86_PMEM_LEGACY
1662	tristate "Support non-standard NVDIMMs and ADR protected memory"
1663	depends on PHYS_ADDR_T_64BIT
1664	depends on BLK_DEV
1665	select X86_PMEM_LEGACY_DEVICE
1666	select LIBNVDIMM
1667	help
1668	  Treat memory marked using the non-standard e820 type of 12 as used
1669	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1670	  The kernel will offer these regions to the 'pmem' driver so
1671	  they can be used for persistent storage.
1672
1673	  Say Y if unsure.
1674
1675config HIGHPTE
1676	bool "Allocate 3rd-level pagetables from highmem"
1677	depends on HIGHMEM
1678	---help---
1679	  The VM uses one page table entry for each page of physical memory.
1680	  For systems with a lot of RAM, this can be wasteful of precious
1681	  low memory.  Setting this option will put user-space page table
1682	  entries in high memory.
1683
1684config X86_CHECK_BIOS_CORRUPTION
1685	bool "Check for low memory corruption"
1686	---help---
1687	  Periodically check for memory corruption in low memory, which
1688	  is suspected to be caused by BIOS.  Even when enabled in the
1689	  configuration, it is disabled at runtime.  Enable it by
1690	  setting "memory_corruption_check=1" on the kernel command
1691	  line.  By default it scans the low 64k of memory every 60
1692	  seconds; see the memory_corruption_check_size and
1693	  memory_corruption_check_period parameters in
1694	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1695
1696	  When enabled with the default parameters, this option has
1697	  almost no overhead, as it reserves a relatively small amount
1698	  of memory and scans it infrequently.  It both detects corruption
1699	  and prevents it from affecting the running system.
1700
1701	  It is, however, intended as a diagnostic tool; if repeatable
1702	  BIOS-originated corruption always affects the same memory,
1703	  you can use memmap= to prevent the kernel from using that
1704	  memory.
1705
1706config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1707	bool "Set the default setting of memory_corruption_check"
1708	depends on X86_CHECK_BIOS_CORRUPTION
1709	default y
1710	---help---
1711	  Set whether the default state of memory_corruption_check is
1712	  on or off.
1713
1714config X86_RESERVE_LOW
1715	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1716	default 64
1717	range 4 640
1718	---help---
1719	  Specify the amount of low memory to reserve for the BIOS.
1720
1721	  The first page contains BIOS data structures that the kernel
1722	  must not use, so that page must always be reserved.
1723
1724	  By default we reserve the first 64K of physical RAM, as a
1725	  number of BIOSes are known to corrupt that memory range
1726	  during events such as suspend/resume or monitor cable
1727	  insertion, so it must not be used by the kernel.
1728
1729	  You can set this to 4 if you are absolutely sure that you
1730	  trust the BIOS to get all its memory reservations and usages
1731	  right.  If you know your BIOS have problems beyond the
1732	  default 64K area, you can set this to 640 to avoid using the
1733	  entire low memory range.
1734
1735	  If you have doubts about the BIOS (e.g. suspend/resume does
1736	  not work or there's kernel crashes after certain hardware
1737	  hotplug events) then you might want to enable
1738	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1739	  typical corruption patterns.
1740
1741	  Leave this to the default value of 64 if you are unsure.
1742
1743config MATH_EMULATION
1744	bool
1745	depends on MODIFY_LDT_SYSCALL
1746	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1747	---help---
1748	  Linux can emulate a math coprocessor (used for floating point
1749	  operations) if you don't have one. 486DX and Pentium processors have
1750	  a math coprocessor built in, 486SX and 386 do not, unless you added
1751	  a 487DX or 387, respectively. (The messages during boot time can
1752	  give you some hints here ["man dmesg"].) Everyone needs either a
1753	  coprocessor or this emulation.
1754
1755	  If you don't have a math coprocessor, you need to say Y here; if you
1756	  say Y here even though you have a coprocessor, the coprocessor will
1757	  be used nevertheless. (This behavior can be changed with the kernel
1758	  command line option "no387", which comes handy if your coprocessor
1759	  is broken. Try "man bootparam" or see the documentation of your boot
1760	  loader (lilo or loadlin) about how to pass options to the kernel at
1761	  boot time.) This means that it is a good idea to say Y here if you
1762	  intend to use this kernel on different machines.
1763
1764	  More information about the internals of the Linux math coprocessor
1765	  emulation can be found in <file:arch/x86/math-emu/README>.
1766
1767	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1768	  kernel, it won't hurt.
1769
1770config MTRR
1771	def_bool y
1772	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1773	---help---
1774	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1775	  the Memory Type Range Registers (MTRRs) may be used to control
1776	  processor access to memory ranges. This is most useful if you have
1777	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1778	  allows bus write transfers to be combined into a larger transfer
1779	  before bursting over the PCI/AGP bus. This can increase performance
1780	  of image write operations 2.5 times or more. Saying Y here creates a
1781	  /proc/mtrr file which may be used to manipulate your processor's
1782	  MTRRs. Typically the X server should use this.
1783
1784	  This code has a reasonably generic interface so that similar
1785	  control registers on other processors can be easily supported
1786	  as well:
1787
1788	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1789	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1790	  these, the ARRs are used to emulate the MTRRs.
1791	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1792	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1793	  write-combining. All of these processors are supported by this code
1794	  and it makes sense to say Y here if you have one of them.
1795
1796	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1797	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1798	  can lead to all sorts of problems, so it's good to say Y here.
1799
1800	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1801	  just add about 9 KB to your kernel.
1802
1803	  See <file:Documentation/x86/mtrr.rst> for more information.
1804
1805config MTRR_SANITIZER
1806	def_bool y
1807	prompt "MTRR cleanup support"
1808	depends on MTRR
1809	---help---
1810	  Convert MTRR layout from continuous to discrete, so X drivers can
1811	  add writeback entries.
1812
1813	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1814	  The largest mtrr entry size for a continuous block can be set with
1815	  mtrr_chunk_size.
1816
1817	  If unsure, say Y.
1818
1819config MTRR_SANITIZER_ENABLE_DEFAULT
1820	int "MTRR cleanup enable value (0-1)"
1821	range 0 1
1822	default "0"
1823	depends on MTRR_SANITIZER
1824	---help---
1825	  Enable mtrr cleanup default value
1826
1827config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1828	int "MTRR cleanup spare reg num (0-7)"
1829	range 0 7
1830	default "1"
1831	depends on MTRR_SANITIZER
1832	---help---
1833	  mtrr cleanup spare entries default, it can be changed via
1834	  mtrr_spare_reg_nr=N on the kernel command line.
1835
1836config X86_PAT
1837	def_bool y
1838	prompt "x86 PAT support" if EXPERT
1839	depends on MTRR
1840	---help---
1841	  Use PAT attributes to setup page level cache control.
1842
1843	  PATs are the modern equivalents of MTRRs and are much more
1844	  flexible than MTRRs.
1845
1846	  Say N here if you see bootup problems (boot crash, boot hang,
1847	  spontaneous reboots) or a non-working video driver.
1848
1849	  If unsure, say Y.
1850
1851config ARCH_USES_PG_UNCACHED
1852	def_bool y
1853	depends on X86_PAT
1854
1855config ARCH_RANDOM
1856	def_bool y
1857	prompt "x86 architectural random number generator" if EXPERT
1858	---help---
1859	  Enable the x86 architectural RDRAND instruction
1860	  (Intel Bull Mountain technology) to generate random numbers.
1861	  If supported, this is a high bandwidth, cryptographically
1862	  secure hardware random number generator.
1863
1864config X86_SMAP
1865	def_bool y
1866	prompt "Supervisor Mode Access Prevention" if EXPERT
1867	---help---
1868	  Supervisor Mode Access Prevention (SMAP) is a security
1869	  feature in newer Intel processors.  There is a small
1870	  performance cost if this enabled and turned on; there is
1871	  also a small increase in the kernel size if this is enabled.
1872
1873	  If unsure, say Y.
1874
1875config X86_UMIP
1876	def_bool y
1877	depends on CPU_SUP_INTEL || CPU_SUP_AMD
1878	prompt "User Mode Instruction Prevention" if EXPERT
1879	---help---
1880	  User Mode Instruction Prevention (UMIP) is a security feature in
1881	  some x86 processors. If enabled, a general protection fault is
1882	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1883	  executed in user mode. These instructions unnecessarily expose
1884	  information about the hardware state.
1885
1886	  The vast majority of applications do not use these instructions.
1887	  For the very few that do, software emulation is provided in
1888	  specific cases in protected and virtual-8086 modes. Emulated
1889	  results are dummy.
1890
1891config X86_INTEL_MEMORY_PROTECTION_KEYS
1892	prompt "Intel Memory Protection Keys"
1893	def_bool y
1894	# Note: only available in 64-bit mode
1895	depends on CPU_SUP_INTEL && X86_64
1896	select ARCH_USES_HIGH_VMA_FLAGS
1897	select ARCH_HAS_PKEYS
1898	---help---
1899	  Memory Protection Keys provides a mechanism for enforcing
1900	  page-based protections, but without requiring modification of the
1901	  page tables when an application changes protection domains.
1902
1903	  For details, see Documentation/core-api/protection-keys.rst
1904
1905	  If unsure, say y.
1906
1907choice
1908	prompt "TSX enable mode"
1909	depends on CPU_SUP_INTEL
1910	default X86_INTEL_TSX_MODE_OFF
1911	help
1912	  Intel's TSX (Transactional Synchronization Extensions) feature
1913	  allows to optimize locking protocols through lock elision which
1914	  can lead to a noticeable performance boost.
1915
1916	  On the other hand it has been shown that TSX can be exploited
1917	  to form side channel attacks (e.g. TAA) and chances are there
1918	  will be more of those attacks discovered in the future.
1919
1920	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1921	  might override this decision by tsx=on the command line parameter.
1922	  Even with TSX enabled, the kernel will attempt to enable the best
1923	  possible TAA mitigation setting depending on the microcode available
1924	  for the particular machine.
1925
1926	  This option allows to set the default tsx mode between tsx=on, =off
1927	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1928	  details.
1929
1930	  Say off if not sure, auto if TSX is in use but it should be used on safe
1931	  platforms or on if TSX is in use and the security aspect of tsx is not
1932	  relevant.
1933
1934config X86_INTEL_TSX_MODE_OFF
1935	bool "off"
1936	help
1937	  TSX is disabled if possible - equals to tsx=off command line parameter.
1938
1939config X86_INTEL_TSX_MODE_ON
1940	bool "on"
1941	help
1942	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1943	  line parameter.
1944
1945config X86_INTEL_TSX_MODE_AUTO
1946	bool "auto"
1947	help
1948	  TSX is enabled on TSX capable HW that is believed to be safe against
1949	  side channel attacks- equals the tsx=auto command line parameter.
1950endchoice
1951
1952config EFI
1953	bool "EFI runtime service support"
1954	depends on ACPI
1955	select UCS2_STRING
1956	select EFI_RUNTIME_WRAPPERS
1957	---help---
1958	  This enables the kernel to use EFI runtime services that are
1959	  available (such as the EFI variable services).
1960
1961	  This option is only useful on systems that have EFI firmware.
1962	  In addition, you should use the latest ELILO loader available
1963	  at <http://elilo.sourceforge.net> in order to take advantage
1964	  of EFI runtime services. However, even with this option, the
1965	  resultant kernel should continue to boot on existing non-EFI
1966	  platforms.
1967
1968config EFI_STUB
1969	bool "EFI stub support"
1970	depends on EFI && !X86_USE_3DNOW
1971	depends on $(cc-option,-mabi=ms) || X86_32
1972	select RELOCATABLE
1973	---help---
1974	  This kernel feature allows a bzImage to be loaded directly
1975	  by EFI firmware without the use of a bootloader.
1976
1977	  See Documentation/admin-guide/efi-stub.rst for more information.
1978
1979config EFI_MIXED
1980	bool "EFI mixed-mode support"
1981	depends on EFI_STUB && X86_64
1982	---help---
1983	   Enabling this feature allows a 64-bit kernel to be booted
1984	   on a 32-bit firmware, provided that your CPU supports 64-bit
1985	   mode.
1986
1987	   Note that it is not possible to boot a mixed-mode enabled
1988	   kernel via the EFI boot stub - a bootloader that supports
1989	   the EFI handover protocol must be used.
1990
1991	   If unsure, say N.
1992
1993config SECCOMP
1994	def_bool y
1995	prompt "Enable seccomp to safely compute untrusted bytecode"
1996	---help---
1997	  This kernel feature is useful for number crunching applications
1998	  that may need to compute untrusted bytecode during their
1999	  execution. By using pipes or other transports made available to
2000	  the process as file descriptors supporting the read/write
2001	  syscalls, it's possible to isolate those applications in
2002	  their own address space using seccomp. Once seccomp is
2003	  enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
2004	  and the task is only allowed to execute a few safe syscalls
2005	  defined by each seccomp mode.
2006
2007	  If unsure, say Y. Only embedded should say N here.
2008
2009source "kernel/Kconfig.hz"
2010
2011config KEXEC
2012	bool "kexec system call"
2013	select KEXEC_CORE
2014	---help---
2015	  kexec is a system call that implements the ability to shutdown your
2016	  current kernel, and to start another kernel.  It is like a reboot
2017	  but it is independent of the system firmware.   And like a reboot
2018	  you can start any kernel with it, not just Linux.
2019
2020	  The name comes from the similarity to the exec system call.
2021
2022	  It is an ongoing process to be certain the hardware in a machine
2023	  is properly shutdown, so do not be surprised if this code does not
2024	  initially work for you.  As of this writing the exact hardware
2025	  interface is strongly in flux, so no good recommendation can be
2026	  made.
2027
2028config KEXEC_FILE
2029	bool "kexec file based system call"
2030	select KEXEC_CORE
2031	select BUILD_BIN2C
2032	depends on X86_64
2033	depends on CRYPTO=y
2034	depends on CRYPTO_SHA256=y
2035	---help---
2036	  This is new version of kexec system call. This system call is
2037	  file based and takes file descriptors as system call argument
2038	  for kernel and initramfs as opposed to list of segments as
2039	  accepted by previous system call.
2040
2041config ARCH_HAS_KEXEC_PURGATORY
2042	def_bool KEXEC_FILE
2043
2044config KEXEC_SIG
2045	bool "Verify kernel signature during kexec_file_load() syscall"
2046	depends on KEXEC_FILE
2047	---help---
2048
2049	  This option makes the kexec_file_load() syscall check for a valid
2050	  signature of the kernel image.  The image can still be loaded without
2051	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2052	  there's a signature that we can check, then it must be valid.
2053
2054	  In addition to this option, you need to enable signature
2055	  verification for the corresponding kernel image type being
2056	  loaded in order for this to work.
2057
2058config KEXEC_SIG_FORCE
2059	bool "Require a valid signature in kexec_file_load() syscall"
2060	depends on KEXEC_SIG
2061	---help---
2062	  This option makes kernel signature verification mandatory for
2063	  the kexec_file_load() syscall.
2064
2065config KEXEC_BZIMAGE_VERIFY_SIG
2066	bool "Enable bzImage signature verification support"
2067	depends on KEXEC_SIG
2068	depends on SIGNED_PE_FILE_VERIFICATION
2069	select SYSTEM_TRUSTED_KEYRING
2070	---help---
2071	  Enable bzImage signature verification support.
2072
2073config CRASH_DUMP
2074	bool "kernel crash dumps"
2075	depends on X86_64 || (X86_32 && HIGHMEM)
2076	---help---
2077	  Generate crash dump after being started by kexec.
2078	  This should be normally only set in special crash dump kernels
2079	  which are loaded in the main kernel with kexec-tools into
2080	  a specially reserved region and then later executed after
2081	  a crash by kdump/kexec. The crash dump kernel must be compiled
2082	  to a memory address not used by the main kernel or BIOS using
2083	  PHYSICAL_START, or it must be built as a relocatable image
2084	  (CONFIG_RELOCATABLE=y).
2085	  For more details see Documentation/admin-guide/kdump/kdump.rst
2086
2087config KEXEC_JUMP
2088	bool "kexec jump"
2089	depends on KEXEC && HIBERNATION
2090	---help---
2091	  Jump between original kernel and kexeced kernel and invoke
2092	  code in physical address mode via KEXEC
2093
2094config PHYSICAL_START
2095	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2096	default "0x1000000"
2097	---help---
2098	  This gives the physical address where the kernel is loaded.
2099
2100	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2101	  bzImage will decompress itself to above physical address and
2102	  run from there. Otherwise, bzImage will run from the address where
2103	  it has been loaded by the boot loader and will ignore above physical
2104	  address.
2105
2106	  In normal kdump cases one does not have to set/change this option
2107	  as now bzImage can be compiled as a completely relocatable image
2108	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2109	  address. This option is mainly useful for the folks who don't want
2110	  to use a bzImage for capturing the crash dump and want to use a
2111	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2112	  to be specifically compiled to run from a specific memory area
2113	  (normally a reserved region) and this option comes handy.
2114
2115	  So if you are using bzImage for capturing the crash dump,
2116	  leave the value here unchanged to 0x1000000 and set
2117	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2118	  for capturing the crash dump change this value to start of
2119	  the reserved region.  In other words, it can be set based on
2120	  the "X" value as specified in the "crashkernel=YM@XM"
2121	  command line boot parameter passed to the panic-ed
2122	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2123	  for more details about crash dumps.
2124
2125	  Usage of bzImage for capturing the crash dump is recommended as
2126	  one does not have to build two kernels. Same kernel can be used
2127	  as production kernel and capture kernel. Above option should have
2128	  gone away after relocatable bzImage support is introduced. But it
2129	  is present because there are users out there who continue to use
2130	  vmlinux for dump capture. This option should go away down the
2131	  line.
2132
2133	  Don't change this unless you know what you are doing.
2134
2135config RELOCATABLE
2136	bool "Build a relocatable kernel"
2137	default y
2138	---help---
2139	  This builds a kernel image that retains relocation information
2140	  so it can be loaded someplace besides the default 1MB.
2141	  The relocations tend to make the kernel binary about 10% larger,
2142	  but are discarded at runtime.
2143
2144	  One use is for the kexec on panic case where the recovery kernel
2145	  must live at a different physical address than the primary
2146	  kernel.
2147
2148	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2149	  it has been loaded at and the compile time physical address
2150	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2151
2152config RANDOMIZE_BASE
2153	bool "Randomize the address of the kernel image (KASLR)"
2154	depends on RELOCATABLE
2155	default y
2156	---help---
2157	  In support of Kernel Address Space Layout Randomization (KASLR),
2158	  this randomizes the physical address at which the kernel image
2159	  is decompressed and the virtual address where the kernel
2160	  image is mapped, as a security feature that deters exploit
2161	  attempts relying on knowledge of the location of kernel
2162	  code internals.
2163
2164	  On 64-bit, the kernel physical and virtual addresses are
2165	  randomized separately. The physical address will be anywhere
2166	  between 16MB and the top of physical memory (up to 64TB). The
2167	  virtual address will be randomized from 16MB up to 1GB (9 bits
2168	  of entropy). Note that this also reduces the memory space
2169	  available to kernel modules from 1.5GB to 1GB.
2170
2171	  On 32-bit, the kernel physical and virtual addresses are
2172	  randomized together. They will be randomized from 16MB up to
2173	  512MB (8 bits of entropy).
2174
2175	  Entropy is generated using the RDRAND instruction if it is
2176	  supported. If RDTSC is supported, its value is mixed into
2177	  the entropy pool as well. If neither RDRAND nor RDTSC are
2178	  supported, then entropy is read from the i8254 timer. The
2179	  usable entropy is limited by the kernel being built using
2180	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2181	  minimum of 2MB. As a result, only 10 bits of entropy are
2182	  theoretically possible, but the implementations are further
2183	  limited due to memory layouts.
2184
2185	  If unsure, say Y.
2186
2187# Relocation on x86 needs some additional build support
2188config X86_NEED_RELOCS
2189	def_bool y
2190	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2191
2192config PHYSICAL_ALIGN
2193	hex "Alignment value to which kernel should be aligned"
2194	default "0x200000"
2195	range 0x2000 0x1000000 if X86_32
2196	range 0x200000 0x1000000 if X86_64
2197	---help---
2198	  This value puts the alignment restrictions on physical address
2199	  where kernel is loaded and run from. Kernel is compiled for an
2200	  address which meets above alignment restriction.
2201
2202	  If bootloader loads the kernel at a non-aligned address and
2203	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2204	  address aligned to above value and run from there.
2205
2206	  If bootloader loads the kernel at a non-aligned address and
2207	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2208	  load address and decompress itself to the address it has been
2209	  compiled for and run from there. The address for which kernel is
2210	  compiled already meets above alignment restrictions. Hence the
2211	  end result is that kernel runs from a physical address meeting
2212	  above alignment restrictions.
2213
2214	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2215	  this value must be a multiple of 0x200000.
2216
2217	  Don't change this unless you know what you are doing.
2218
2219config DYNAMIC_MEMORY_LAYOUT
2220	bool
2221	---help---
2222	  This option makes base addresses of vmalloc and vmemmap as well as
2223	  __PAGE_OFFSET movable during boot.
2224
2225config RANDOMIZE_MEMORY
2226	bool "Randomize the kernel memory sections"
2227	depends on X86_64
2228	depends on RANDOMIZE_BASE
2229	select DYNAMIC_MEMORY_LAYOUT
2230	default RANDOMIZE_BASE
2231	---help---
2232	   Randomizes the base virtual address of kernel memory sections
2233	   (physical memory mapping, vmalloc & vmemmap). This security feature
2234	   makes exploits relying on predictable memory locations less reliable.
2235
2236	   The order of allocations remains unchanged. Entropy is generated in
2237	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2238	   configuration have in average 30,000 different possible virtual
2239	   addresses for each memory section.
2240
2241	   If unsure, say Y.
2242
2243config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2244	hex "Physical memory mapping padding" if EXPERT
2245	depends on RANDOMIZE_MEMORY
2246	default "0xa" if MEMORY_HOTPLUG
2247	default "0x0"
2248	range 0x1 0x40 if MEMORY_HOTPLUG
2249	range 0x0 0x40
2250	---help---
2251	   Define the padding in terabytes added to the existing physical
2252	   memory size during kernel memory randomization. It is useful
2253	   for memory hotplug support but reduces the entropy available for
2254	   address randomization.
2255
2256	   If unsure, leave at the default value.
2257
2258config HOTPLUG_CPU
2259	def_bool y
2260	depends on SMP
2261
2262config BOOTPARAM_HOTPLUG_CPU0
2263	bool "Set default setting of cpu0_hotpluggable"
2264	depends on HOTPLUG_CPU
2265	---help---
2266	  Set whether default state of cpu0_hotpluggable is on or off.
2267
2268	  Say Y here to enable CPU0 hotplug by default. If this switch
2269	  is turned on, there is no need to give cpu0_hotplug kernel
2270	  parameter and the CPU0 hotplug feature is enabled by default.
2271
2272	  Please note: there are two known CPU0 dependencies if you want
2273	  to enable the CPU0 hotplug feature either by this switch or by
2274	  cpu0_hotplug kernel parameter.
2275
2276	  First, resume from hibernate or suspend always starts from CPU0.
2277	  So hibernate and suspend are prevented if CPU0 is offline.
2278
2279	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2280	  offline if any interrupt can not migrate out of CPU0. There may
2281	  be other CPU0 dependencies.
2282
2283	  Please make sure the dependencies are under your control before
2284	  you enable this feature.
2285
2286	  Say N if you don't want to enable CPU0 hotplug feature by default.
2287	  You still can enable the CPU0 hotplug feature at boot by kernel
2288	  parameter cpu0_hotplug.
2289
2290config DEBUG_HOTPLUG_CPU0
2291	def_bool n
2292	prompt "Debug CPU0 hotplug"
2293	depends on HOTPLUG_CPU
2294	---help---
2295	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2296	  soon as possible and boots up userspace with CPU0 offlined. User
2297	  can online CPU0 back after boot time.
2298
2299	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2300	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2301	  compilation or giving cpu0_hotplug kernel parameter at boot.
2302
2303	  If unsure, say N.
2304
2305config COMPAT_VDSO
2306	def_bool n
2307	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2308	depends on COMPAT_32
2309	---help---
2310	  Certain buggy versions of glibc will crash if they are
2311	  presented with a 32-bit vDSO that is not mapped at the address
2312	  indicated in its segment table.
2313
2314	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2315	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2316	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2317	  the only released version with the bug, but OpenSUSE 9
2318	  contains a buggy "glibc 2.3.2".
2319
2320	  The symptom of the bug is that everything crashes on startup, saying:
2321	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2322
2323	  Saying Y here changes the default value of the vdso32 boot
2324	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2325	  This works around the glibc bug but hurts performance.
2326
2327	  If unsure, say N: if you are compiling your own kernel, you
2328	  are unlikely to be using a buggy version of glibc.
2329
2330choice
2331	prompt "vsyscall table for legacy applications"
2332	depends on X86_64
2333	default LEGACY_VSYSCALL_XONLY
2334	help
2335	  Legacy user code that does not know how to find the vDSO expects
2336	  to be able to issue three syscalls by calling fixed addresses in
2337	  kernel space. Since this location is not randomized with ASLR,
2338	  it can be used to assist security vulnerability exploitation.
2339
2340	  This setting can be changed at boot time via the kernel command
2341	  line parameter vsyscall=[emulate|xonly|none].
2342
2343	  On a system with recent enough glibc (2.14 or newer) and no
2344	  static binaries, you can say None without a performance penalty
2345	  to improve security.
2346
2347	  If unsure, select "Emulate execution only".
2348
2349	config LEGACY_VSYSCALL_EMULATE
2350		bool "Full emulation"
2351		help
2352		  The kernel traps and emulates calls into the fixed vsyscall
2353		  address mapping. This makes the mapping non-executable, but
2354		  it still contains readable known contents, which could be
2355		  used in certain rare security vulnerability exploits. This
2356		  configuration is recommended when using legacy userspace
2357		  that still uses vsyscalls along with legacy binary
2358		  instrumentation tools that require code to be readable.
2359
2360		  An example of this type of legacy userspace is running
2361		  Pin on an old binary that still uses vsyscalls.
2362
2363	config LEGACY_VSYSCALL_XONLY
2364		bool "Emulate execution only"
2365		help
2366		  The kernel traps and emulates calls into the fixed vsyscall
2367		  address mapping and does not allow reads.  This
2368		  configuration is recommended when userspace might use the
2369		  legacy vsyscall area but support for legacy binary
2370		  instrumentation of legacy code is not needed.  It mitigates
2371		  certain uses of the vsyscall area as an ASLR-bypassing
2372		  buffer.
2373
2374	config LEGACY_VSYSCALL_NONE
2375		bool "None"
2376		help
2377		  There will be no vsyscall mapping at all. This will
2378		  eliminate any risk of ASLR bypass due to the vsyscall
2379		  fixed address mapping. Attempts to use the vsyscalls
2380		  will be reported to dmesg, so that either old or
2381		  malicious userspace programs can be identified.
2382
2383endchoice
2384
2385config CMDLINE_BOOL
2386	bool "Built-in kernel command line"
2387	---help---
2388	  Allow for specifying boot arguments to the kernel at
2389	  build time.  On some systems (e.g. embedded ones), it is
2390	  necessary or convenient to provide some or all of the
2391	  kernel boot arguments with the kernel itself (that is,
2392	  to not rely on the boot loader to provide them.)
2393
2394	  To compile command line arguments into the kernel,
2395	  set this option to 'Y', then fill in the
2396	  boot arguments in CONFIG_CMDLINE.
2397
2398	  Systems with fully functional boot loaders (i.e. non-embedded)
2399	  should leave this option set to 'N'.
2400
2401config CMDLINE
2402	string "Built-in kernel command string"
2403	depends on CMDLINE_BOOL
2404	default ""
2405	---help---
2406	  Enter arguments here that should be compiled into the kernel
2407	  image and used at boot time.  If the boot loader provides a
2408	  command line at boot time, it is appended to this string to
2409	  form the full kernel command line, when the system boots.
2410
2411	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2412	  change this behavior.
2413
2414	  In most cases, the command line (whether built-in or provided
2415	  by the boot loader) should specify the device for the root
2416	  file system.
2417
2418config CMDLINE_OVERRIDE
2419	bool "Built-in command line overrides boot loader arguments"
2420	depends on CMDLINE_BOOL
2421	---help---
2422	  Set this option to 'Y' to have the kernel ignore the boot loader
2423	  command line, and use ONLY the built-in command line.
2424
2425	  This is used to work around broken boot loaders.  This should
2426	  be set to 'N' under normal conditions.
2427
2428config MODIFY_LDT_SYSCALL
2429	bool "Enable the LDT (local descriptor table)" if EXPERT
2430	default y
2431	---help---
2432	  Linux can allow user programs to install a per-process x86
2433	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2434	  call.  This is required to run 16-bit or segmented code such as
2435	  DOSEMU or some Wine programs.  It is also used by some very old
2436	  threading libraries.
2437
2438	  Enabling this feature adds a small amount of overhead to
2439	  context switches and increases the low-level kernel attack
2440	  surface.  Disabling it removes the modify_ldt(2) system call.
2441
2442	  Saying 'N' here may make sense for embedded or server kernels.
2443
2444source "kernel/livepatch/Kconfig"
2445
2446endmenu
2447
2448config ARCH_HAS_ADD_PAGES
2449	def_bool y
2450	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2451
2452config ARCH_ENABLE_MEMORY_HOTPLUG
2453	def_bool y
2454	depends on X86_64 || (X86_32 && HIGHMEM)
2455
2456config ARCH_ENABLE_MEMORY_HOTREMOVE
2457	def_bool y
2458	depends on MEMORY_HOTPLUG
2459
2460config USE_PERCPU_NUMA_NODE_ID
2461	def_bool y
2462	depends on NUMA
2463
2464config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2465	def_bool y
2466	depends on X86_64 || X86_PAE
2467
2468config ARCH_ENABLE_HUGEPAGE_MIGRATION
2469	def_bool y
2470	depends on X86_64 && HUGETLB_PAGE && MIGRATION
2471
2472config ARCH_ENABLE_THP_MIGRATION
2473	def_bool y
2474	depends on X86_64 && TRANSPARENT_HUGEPAGE
2475
2476menu "Power management and ACPI options"
2477
2478config ARCH_HIBERNATION_HEADER
2479	def_bool y
2480	depends on HIBERNATION
2481
2482source "kernel/power/Kconfig"
2483
2484source "drivers/acpi/Kconfig"
2485
2486source "drivers/sfi/Kconfig"
2487
2488config X86_APM_BOOT
2489	def_bool y
2490	depends on APM
2491
2492menuconfig APM
2493	tristate "APM (Advanced Power Management) BIOS support"
2494	depends on X86_32 && PM_SLEEP
2495	---help---
2496	  APM is a BIOS specification for saving power using several different
2497	  techniques. This is mostly useful for battery powered laptops with
2498	  APM compliant BIOSes. If you say Y here, the system time will be
2499	  reset after a RESUME operation, the /proc/apm device will provide
2500	  battery status information, and user-space programs will receive
2501	  notification of APM "events" (e.g. battery status change).
2502
2503	  If you select "Y" here, you can disable actual use of the APM
2504	  BIOS by passing the "apm=off" option to the kernel at boot time.
2505
2506	  Note that the APM support is almost completely disabled for
2507	  machines with more than one CPU.
2508
2509	  In order to use APM, you will need supporting software. For location
2510	  and more information, read <file:Documentation/power/apm-acpi.rst>
2511	  and the Battery Powered Linux mini-HOWTO, available from
2512	  <http://www.tldp.org/docs.html#howto>.
2513
2514	  This driver does not spin down disk drives (see the hdparm(8)
2515	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2516	  VESA-compliant "green" monitors.
2517
2518	  This driver does not support the TI 4000M TravelMate and the ACER
2519	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2520	  desktop machines also don't have compliant BIOSes, and this driver
2521	  may cause those machines to panic during the boot phase.
2522
2523	  Generally, if you don't have a battery in your machine, there isn't
2524	  much point in using this driver and you should say N. If you get
2525	  random kernel OOPSes or reboots that don't seem to be related to
2526	  anything, try disabling/enabling this option (or disabling/enabling
2527	  APM in your BIOS).
2528
2529	  Some other things you should try when experiencing seemingly random,
2530	  "weird" problems:
2531
2532	  1) make sure that you have enough swap space and that it is
2533	  enabled.
2534	  2) pass the "no-hlt" option to the kernel
2535	  3) switch on floating point emulation in the kernel and pass
2536	  the "no387" option to the kernel
2537	  4) pass the "floppy=nodma" option to the kernel
2538	  5) pass the "mem=4M" option to the kernel (thereby disabling
2539	  all but the first 4 MB of RAM)
2540	  6) make sure that the CPU is not over clocked.
2541	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2542	  8) disable the cache from your BIOS settings
2543	  9) install a fan for the video card or exchange video RAM
2544	  10) install a better fan for the CPU
2545	  11) exchange RAM chips
2546	  12) exchange the motherboard.
2547
2548	  To compile this driver as a module, choose M here: the
2549	  module will be called apm.
2550
2551if APM
2552
2553config APM_IGNORE_USER_SUSPEND
2554	bool "Ignore USER SUSPEND"
2555	---help---
2556	  This option will ignore USER SUSPEND requests. On machines with a
2557	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2558	  series notebooks, it is necessary to say Y because of a BIOS bug.
2559
2560config APM_DO_ENABLE
2561	bool "Enable PM at boot time"
2562	---help---
2563	  Enable APM features at boot time. From page 36 of the APM BIOS
2564	  specification: "When disabled, the APM BIOS does not automatically
2565	  power manage devices, enter the Standby State, enter the Suspend
2566	  State, or take power saving steps in response to CPU Idle calls."
2567	  This driver will make CPU Idle calls when Linux is idle (unless this
2568	  feature is turned off -- see "Do CPU IDLE calls", below). This
2569	  should always save battery power, but more complicated APM features
2570	  will be dependent on your BIOS implementation. You may need to turn
2571	  this option off if your computer hangs at boot time when using APM
2572	  support, or if it beeps continuously instead of suspending. Turn
2573	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2574	  T400CDT. This is off by default since most machines do fine without
2575	  this feature.
2576
2577config APM_CPU_IDLE
2578	depends on CPU_IDLE
2579	bool "Make CPU Idle calls when idle"
2580	---help---
2581	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2582	  On some machines, this can activate improved power savings, such as
2583	  a slowed CPU clock rate, when the machine is idle. These idle calls
2584	  are made after the idle loop has run for some length of time (e.g.,
2585	  333 mS). On some machines, this will cause a hang at boot time or
2586	  whenever the CPU becomes idle. (On machines with more than one CPU,
2587	  this option does nothing.)
2588
2589config APM_DISPLAY_BLANK
2590	bool "Enable console blanking using APM"
2591	---help---
2592	  Enable console blanking using the APM. Some laptops can use this to
2593	  turn off the LCD backlight when the screen blanker of the Linux
2594	  virtual console blanks the screen. Note that this is only used by
2595	  the virtual console screen blanker, and won't turn off the backlight
2596	  when using the X Window system. This also doesn't have anything to
2597	  do with your VESA-compliant power-saving monitor. Further, this
2598	  option doesn't work for all laptops -- it might not turn off your
2599	  backlight at all, or it might print a lot of errors to the console,
2600	  especially if you are using gpm.
2601
2602config APM_ALLOW_INTS
2603	bool "Allow interrupts during APM BIOS calls"
2604	---help---
2605	  Normally we disable external interrupts while we are making calls to
2606	  the APM BIOS as a measure to lessen the effects of a badly behaving
2607	  BIOS implementation.  The BIOS should reenable interrupts if it
2608	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2609	  many of the newer IBM Thinkpads.  If you experience hangs when you
2610	  suspend, try setting this to Y.  Otherwise, say N.
2611
2612endif # APM
2613
2614source "drivers/cpufreq/Kconfig"
2615
2616source "drivers/cpuidle/Kconfig"
2617
2618source "drivers/idle/Kconfig"
2619
2620endmenu
2621
2622
2623menu "Bus options (PCI etc.)"
2624
2625choice
2626	prompt "PCI access mode"
2627	depends on X86_32 && PCI
2628	default PCI_GOANY
2629	---help---
2630	  On PCI systems, the BIOS can be used to detect the PCI devices and
2631	  determine their configuration. However, some old PCI motherboards
2632	  have BIOS bugs and may crash if this is done. Also, some embedded
2633	  PCI-based systems don't have any BIOS at all. Linux can also try to
2634	  detect the PCI hardware directly without using the BIOS.
2635
2636	  With this option, you can specify how Linux should detect the
2637	  PCI devices. If you choose "BIOS", the BIOS will be used,
2638	  if you choose "Direct", the BIOS won't be used, and if you
2639	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2640	  If you choose "Any", the kernel will try MMCONFIG, then the
2641	  direct access method and falls back to the BIOS if that doesn't
2642	  work. If unsure, go with the default, which is "Any".
2643
2644config PCI_GOBIOS
2645	bool "BIOS"
2646
2647config PCI_GOMMCONFIG
2648	bool "MMConfig"
2649
2650config PCI_GODIRECT
2651	bool "Direct"
2652
2653config PCI_GOOLPC
2654	bool "OLPC XO-1"
2655	depends on OLPC
2656
2657config PCI_GOANY
2658	bool "Any"
2659
2660endchoice
2661
2662config PCI_BIOS
2663	def_bool y
2664	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2665
2666# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2667config PCI_DIRECT
2668	def_bool y
2669	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2670
2671config PCI_MMCONFIG
2672	bool "Support mmconfig PCI config space access" if X86_64
2673	default y
2674	depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2675	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2676
2677config PCI_OLPC
2678	def_bool y
2679	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2680
2681config PCI_XEN
2682	def_bool y
2683	depends on PCI && XEN
2684	select SWIOTLB_XEN
2685
2686config MMCONF_FAM10H
2687	def_bool y
2688	depends on X86_64 && PCI_MMCONFIG && ACPI
2689
2690config PCI_CNB20LE_QUIRK
2691	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2692	depends on PCI
2693	help
2694	  Read the PCI windows out of the CNB20LE host bridge. This allows
2695	  PCI hotplug to work on systems with the CNB20LE chipset which do
2696	  not have ACPI.
2697
2698	  There's no public spec for this chipset, and this functionality
2699	  is known to be incomplete.
2700
2701	  You should say N unless you know you need this.
2702
2703config ISA_BUS
2704	bool "ISA bus support on modern systems" if EXPERT
2705	help
2706	  Expose ISA bus device drivers and options available for selection and
2707	  configuration. Enable this option if your target machine has an ISA
2708	  bus. ISA is an older system, displaced by PCI and newer bus
2709	  architectures -- if your target machine is modern, it probably does
2710	  not have an ISA bus.
2711
2712	  If unsure, say N.
2713
2714# x86_64 have no ISA slots, but can have ISA-style DMA.
2715config ISA_DMA_API
2716	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2717	default y
2718	help
2719	  Enables ISA-style DMA support for devices requiring such controllers.
2720	  If unsure, say Y.
2721
2722if X86_32
2723
2724config ISA
2725	bool "ISA support"
2726	---help---
2727	  Find out whether you have ISA slots on your motherboard.  ISA is the
2728	  name of a bus system, i.e. the way the CPU talks to the other stuff
2729	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2730	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2731	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2732
2733config SCx200
2734	tristate "NatSemi SCx200 support"
2735	---help---
2736	  This provides basic support for National Semiconductor's
2737	  (now AMD's) Geode processors.  The driver probes for the
2738	  PCI-IDs of several on-chip devices, so its a good dependency
2739	  for other scx200_* drivers.
2740
2741	  If compiled as a module, the driver is named scx200.
2742
2743config SCx200HR_TIMER
2744	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2745	depends on SCx200
2746	default y
2747	---help---
2748	  This driver provides a clocksource built upon the on-chip
2749	  27MHz high-resolution timer.  Its also a workaround for
2750	  NSC Geode SC-1100's buggy TSC, which loses time when the
2751	  processor goes idle (as is done by the scheduler).  The
2752	  other workaround is idle=poll boot option.
2753
2754config OLPC
2755	bool "One Laptop Per Child support"
2756	depends on !X86_PAE
2757	select GPIOLIB
2758	select OF
2759	select OF_PROMTREE
2760	select IRQ_DOMAIN
2761	select OLPC_EC
2762	---help---
2763	  Add support for detecting the unique features of the OLPC
2764	  XO hardware.
2765
2766config OLPC_XO1_PM
2767	bool "OLPC XO-1 Power Management"
2768	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2769	---help---
2770	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2771
2772config OLPC_XO1_RTC
2773	bool "OLPC XO-1 Real Time Clock"
2774	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2775	---help---
2776	  Add support for the XO-1 real time clock, which can be used as a
2777	  programmable wakeup source.
2778
2779config OLPC_XO1_SCI
2780	bool "OLPC XO-1 SCI extras"
2781	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2782	depends on INPUT=y
2783	select POWER_SUPPLY
2784	---help---
2785	  Add support for SCI-based features of the OLPC XO-1 laptop:
2786	   - EC-driven system wakeups
2787	   - Power button
2788	   - Ebook switch
2789	   - Lid switch
2790	   - AC adapter status updates
2791	   - Battery status updates
2792
2793config OLPC_XO15_SCI
2794	bool "OLPC XO-1.5 SCI extras"
2795	depends on OLPC && ACPI
2796	select POWER_SUPPLY
2797	---help---
2798	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2799	   - EC-driven system wakeups
2800	   - AC adapter status updates
2801	   - Battery status updates
2802
2803config ALIX
2804	bool "PCEngines ALIX System Support (LED setup)"
2805	select GPIOLIB
2806	---help---
2807	  This option enables system support for the PCEngines ALIX.
2808	  At present this just sets up LEDs for GPIO control on
2809	  ALIX2/3/6 boards.  However, other system specific setup should
2810	  get added here.
2811
2812	  Note: You must still enable the drivers for GPIO and LED support
2813	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2814
2815	  Note: You have to set alix.force=1 for boards with Award BIOS.
2816
2817config NET5501
2818	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2819	select GPIOLIB
2820	---help---
2821	  This option enables system support for the Soekris Engineering net5501.
2822
2823config GEOS
2824	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2825	select GPIOLIB
2826	depends on DMI
2827	---help---
2828	  This option enables system support for the Traverse Technologies GEOS.
2829
2830config TS5500
2831	bool "Technologic Systems TS-5500 platform support"
2832	depends on MELAN
2833	select CHECK_SIGNATURE
2834	select NEW_LEDS
2835	select LEDS_CLASS
2836	---help---
2837	  This option enables system support for the Technologic Systems TS-5500.
2838
2839endif # X86_32
2840
2841config AMD_NB
2842	def_bool y
2843	depends on CPU_SUP_AMD && PCI
2844
2845config X86_SYSFB
2846	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2847	help
2848	  Firmwares often provide initial graphics framebuffers so the BIOS,
2849	  bootloader or kernel can show basic video-output during boot for
2850	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2851	  Extensions and EFI-framebuffers for this, which are mostly limited
2852	  to x86.
2853	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2854	  framebuffers so the new generic system-framebuffer drivers can be
2855	  used on x86. If the framebuffer is not compatible with the generic
2856	  modes, it is advertised as fallback platform framebuffer so legacy
2857	  drivers like efifb, vesafb and uvesafb can pick it up.
2858	  If this option is not selected, all system framebuffers are always
2859	  marked as fallback platform framebuffers as usual.
2860
2861	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2862	  not be able to pick up generic system framebuffers if this option
2863	  is selected. You are highly encouraged to enable simplefb as
2864	  replacement if you select this option. simplefb can correctly deal
2865	  with generic system framebuffers. But you should still keep vesafb
2866	  and others enabled as fallback if a system framebuffer is
2867	  incompatible with simplefb.
2868
2869	  If unsure, say Y.
2870
2871endmenu
2872
2873
2874menu "Binary Emulations"
2875
2876config IA32_EMULATION
2877	bool "IA32 Emulation"
2878	depends on X86_64
2879	select ARCH_WANT_OLD_COMPAT_IPC
2880	select BINFMT_ELF
2881	select COMPAT_BINFMT_ELF
2882	select COMPAT_OLD_SIGACTION
2883	---help---
2884	  Include code to run legacy 32-bit programs under a
2885	  64-bit kernel. You should likely turn this on, unless you're
2886	  100% sure that you don't have any 32-bit programs left.
2887
2888config IA32_AOUT
2889	tristate "IA32 a.out support"
2890	depends on IA32_EMULATION
2891	depends on BROKEN
2892	---help---
2893	  Support old a.out binaries in the 32bit emulation.
2894
2895config X86_X32
2896	bool "x32 ABI for 64-bit mode"
2897	depends on X86_64
2898	---help---
2899	  Include code to run binaries for the x32 native 32-bit ABI
2900	  for 64-bit processors.  An x32 process gets access to the
2901	  full 64-bit register file and wide data path while leaving
2902	  pointers at 32 bits for smaller memory footprint.
2903
2904	  You will need a recent binutils (2.22 or later) with
2905	  elf32_x86_64 support enabled to compile a kernel with this
2906	  option set.
2907
2908config COMPAT_32
2909	def_bool y
2910	depends on IA32_EMULATION || X86_32
2911	select HAVE_UID16
2912	select OLD_SIGSUSPEND3
2913
2914config COMPAT
2915	def_bool y
2916	depends on IA32_EMULATION || X86_X32
2917
2918if COMPAT
2919config COMPAT_FOR_U64_ALIGNMENT
2920	def_bool y
2921
2922config SYSVIPC_COMPAT
2923	def_bool y
2924	depends on SYSVIPC
2925endif
2926
2927endmenu
2928
2929
2930config HAVE_ATOMIC_IOMAP
2931	def_bool y
2932	depends on X86_32
2933
2934source "drivers/firmware/Kconfig"
2935
2936source "arch/x86/kvm/Kconfig"
2937