xref: /openbmc/linux/arch/x86/Kconfig (revision 4a3fad70)
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_AOUT
18	select HAVE_GENERIC_DMA_COHERENT
19	select MODULES_USE_ELF_REL
20	select OLD_SIGACTION
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 if (MEMORY_ISOLATION && COMPACTION) || CMA
27	select ARCH_SUPPORTS_INT128
28	select ARCH_USE_CMPXCHG_LOCKREF
29	select HAVE_ARCH_SOFT_DIRTY
30	select MODULES_USE_ELF_RELA
31	select X86_DEV_DMA_OPS
32
33#
34# Arch settings
35#
36# ( Note that options that are marked 'if X86_64' could in principle be
37#   ported to 32-bit as well. )
38#
39config X86
40	def_bool y
41	#
42	# Note: keep this list sorted alphabetically
43	#
44	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
45	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
46	select ANON_INODES
47	select ARCH_CLOCKSOURCE_DATA
48	select ARCH_DISCARD_MEMBLOCK
49	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
50	select ARCH_HAS_DEBUG_VIRTUAL
51	select ARCH_HAS_DEVMEM_IS_ALLOWED
52	select ARCH_HAS_ELF_RANDOMIZE
53	select ARCH_HAS_FAST_MULTIPLIER
54	select ARCH_HAS_FORTIFY_SOURCE
55	select ARCH_HAS_GCOV_PROFILE_ALL
56	select ARCH_HAS_KCOV			if X86_64
57	select ARCH_HAS_PMEM_API		if X86_64
58	# Causing hangs/crashes, see the commit that added this change for details.
59	select ARCH_HAS_REFCOUNT
60	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
61	select ARCH_HAS_SET_MEMORY
62	select ARCH_HAS_SG_CHAIN
63	select ARCH_HAS_STRICT_KERNEL_RWX
64	select ARCH_HAS_STRICT_MODULE_RWX
65	select ARCH_HAS_UBSAN_SANITIZE_ALL
66	select ARCH_HAS_ZONE_DEVICE		if X86_64
67	select ARCH_HAVE_NMI_SAFE_CMPXCHG
68	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
69	select ARCH_MIGHT_HAVE_PC_PARPORT
70	select ARCH_MIGHT_HAVE_PC_SERIO
71	select ARCH_SUPPORTS_ATOMIC_RMW
72	select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
73	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
74	select ARCH_USE_BUILTIN_BSWAP
75	select ARCH_USE_QUEUED_RWLOCKS
76	select ARCH_USE_QUEUED_SPINLOCKS
77	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
78	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
79	select ARCH_WANTS_THP_SWAP		if X86_64
80	select BUILDTIME_EXTABLE_SORT
81	select CLKEVT_I8253
82	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
83	select CLOCKSOURCE_WATCHDOG
84	select DCACHE_WORD_ACCESS
85	select EDAC_ATOMIC_SCRUB
86	select EDAC_SUPPORT
87	select GENERIC_CLOCKEVENTS
88	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
89	select GENERIC_CLOCKEVENTS_MIN_ADJUST
90	select GENERIC_CMOS_UPDATE
91	select GENERIC_CPU_AUTOPROBE
92	select GENERIC_EARLY_IOREMAP
93	select GENERIC_FIND_FIRST_BIT
94	select GENERIC_IOMAP
95	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
96	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
97	select GENERIC_IRQ_MIGRATION		if SMP
98	select GENERIC_IRQ_PROBE
99	select GENERIC_IRQ_RESERVATION_MODE
100	select GENERIC_IRQ_SHOW
101	select GENERIC_PENDING_IRQ		if SMP
102	select GENERIC_SMP_IDLE_THREAD
103	select GENERIC_STRNCPY_FROM_USER
104	select GENERIC_STRNLEN_USER
105	select GENERIC_TIME_VSYSCALL
106	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
107	select HAVE_ACPI_APEI			if ACPI
108	select HAVE_ACPI_APEI_NMI		if ACPI
109	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
110	select HAVE_ARCH_AUDITSYSCALL
111	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
112	select HAVE_ARCH_JUMP_LABEL
113	select HAVE_ARCH_KASAN			if X86_64
114	select HAVE_ARCH_KGDB
115	select HAVE_ARCH_MMAP_RND_BITS		if MMU
116	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
117	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
118	select HAVE_ARCH_SECCOMP_FILTER
119	select HAVE_ARCH_TRACEHOOK
120	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
121	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
122	select HAVE_ARCH_VMAP_STACK		if X86_64
123	select HAVE_ARCH_WITHIN_STACK_FRAMES
124	select HAVE_CC_STACKPROTECTOR
125	select HAVE_CMPXCHG_DOUBLE
126	select HAVE_CMPXCHG_LOCAL
127	select HAVE_CONTEXT_TRACKING		if X86_64
128	select HAVE_COPY_THREAD_TLS
129	select HAVE_C_RECORDMCOUNT
130	select HAVE_DEBUG_KMEMLEAK
131	select HAVE_DEBUG_STACKOVERFLOW
132	select HAVE_DMA_API_DEBUG
133	select HAVE_DMA_CONTIGUOUS
134	select HAVE_DYNAMIC_FTRACE
135	select HAVE_DYNAMIC_FTRACE_WITH_REGS
136	select HAVE_EBPF_JIT			if X86_64
137	select HAVE_EFFICIENT_UNALIGNED_ACCESS
138	select HAVE_EXIT_THREAD
139	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
140	select HAVE_FTRACE_MCOUNT_RECORD
141	select HAVE_FUNCTION_GRAPH_TRACER
142	select HAVE_FUNCTION_TRACER
143	select HAVE_GCC_PLUGINS
144	select HAVE_HW_BREAKPOINT
145	select HAVE_IDE
146	select HAVE_IOREMAP_PROT
147	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
148	select HAVE_IRQ_TIME_ACCOUNTING
149	select HAVE_KERNEL_BZIP2
150	select HAVE_KERNEL_GZIP
151	select HAVE_KERNEL_LZ4
152	select HAVE_KERNEL_LZMA
153	select HAVE_KERNEL_LZO
154	select HAVE_KERNEL_XZ
155	select HAVE_KPROBES
156	select HAVE_KPROBES_ON_FTRACE
157	select HAVE_KRETPROBES
158	select HAVE_KVM
159	select HAVE_LIVEPATCH			if X86_64
160	select HAVE_MEMBLOCK
161	select HAVE_MEMBLOCK_NODE_MAP
162	select HAVE_MIXED_BREAKPOINTS_REGS
163	select HAVE_MOD_ARCH_SPECIFIC
164	select HAVE_NMI
165	select HAVE_OPROFILE
166	select HAVE_OPTPROBES
167	select HAVE_PCSPKR_PLATFORM
168	select HAVE_PERF_EVENTS
169	select HAVE_PERF_EVENTS_NMI
170	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
171	select HAVE_PERF_REGS
172	select HAVE_PERF_USER_STACK_DUMP
173	select HAVE_RCU_TABLE_FREE
174	select HAVE_REGS_AND_STACK_ACCESS_API
175	select HAVE_RELIABLE_STACKTRACE		if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION
176	select HAVE_STACK_VALIDATION		if X86_64
177	select HAVE_SYSCALL_TRACEPOINTS
178	select HAVE_UNSTABLE_SCHED_CLOCK
179	select HAVE_USER_RETURN_NOTIFIER
180	select IRQ_FORCED_THREADING
181	select PCI_LOCKLESS_CONFIG
182	select PERF_EVENTS
183	select RTC_LIB
184	select RTC_MC146818_LIB
185	select SPARSE_IRQ
186	select SRCU
187	select SYSCTL_EXCEPTION_TRACE
188	select THREAD_INFO_IN_TASK
189	select USER_STACKTRACE_SUPPORT
190	select VIRT_TO_BUS
191	select X86_FEATURE_NAMES		if PROC_FS
192
193config INSTRUCTION_DECODER
194	def_bool y
195	depends on KPROBES || PERF_EVENTS || UPROBES
196
197config OUTPUT_FORMAT
198	string
199	default "elf32-i386" if X86_32
200	default "elf64-x86-64" if X86_64
201
202config ARCH_DEFCONFIG
203	string
204	default "arch/x86/configs/i386_defconfig" if X86_32
205	default "arch/x86/configs/x86_64_defconfig" if X86_64
206
207config LOCKDEP_SUPPORT
208	def_bool y
209
210config STACKTRACE_SUPPORT
211	def_bool y
212
213config MMU
214	def_bool y
215
216config ARCH_MMAP_RND_BITS_MIN
217	default 28 if 64BIT
218	default 8
219
220config ARCH_MMAP_RND_BITS_MAX
221	default 32 if 64BIT
222	default 16
223
224config ARCH_MMAP_RND_COMPAT_BITS_MIN
225	default 8
226
227config ARCH_MMAP_RND_COMPAT_BITS_MAX
228	default 16
229
230config SBUS
231	bool
232
233config NEED_DMA_MAP_STATE
234	def_bool y
235	depends on X86_64 || INTEL_IOMMU || DMA_API_DEBUG || SWIOTLB
236
237config NEED_SG_DMA_LENGTH
238	def_bool y
239
240config GENERIC_ISA_DMA
241	def_bool y
242	depends on ISA_DMA_API
243
244config GENERIC_BUG
245	def_bool y
246	depends on BUG
247	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
248
249config GENERIC_BUG_RELATIVE_POINTERS
250	bool
251
252config GENERIC_HWEIGHT
253	def_bool y
254
255config ARCH_MAY_HAVE_PC_FDC
256	def_bool y
257	depends on ISA_DMA_API
258
259config RWSEM_XCHGADD_ALGORITHM
260	def_bool y
261
262config GENERIC_CALIBRATE_DELAY
263	def_bool y
264
265config ARCH_HAS_CPU_RELAX
266	def_bool y
267
268config ARCH_HAS_CACHE_LINE_SIZE
269	def_bool y
270
271config HAVE_SETUP_PER_CPU_AREA
272	def_bool y
273
274config NEED_PER_CPU_EMBED_FIRST_CHUNK
275	def_bool y
276
277config NEED_PER_CPU_PAGE_FIRST_CHUNK
278	def_bool y
279
280config ARCH_HIBERNATION_POSSIBLE
281	def_bool y
282
283config ARCH_SUSPEND_POSSIBLE
284	def_bool y
285
286config ARCH_WANT_HUGE_PMD_SHARE
287	def_bool y
288
289config ARCH_WANT_GENERAL_HUGETLB
290	def_bool y
291
292config ZONE_DMA32
293	def_bool y if X86_64
294
295config AUDIT_ARCH
296	def_bool y if X86_64
297
298config ARCH_SUPPORTS_OPTIMIZED_INLINING
299	def_bool y
300
301config ARCH_SUPPORTS_DEBUG_PAGEALLOC
302	def_bool y
303
304config KASAN_SHADOW_OFFSET
305	hex
306	depends on KASAN
307	default 0xdffffc0000000000
308
309config HAVE_INTEL_TXT
310	def_bool y
311	depends on INTEL_IOMMU && ACPI
312
313config X86_32_SMP
314	def_bool y
315	depends on X86_32 && SMP
316
317config X86_64_SMP
318	def_bool y
319	depends on X86_64 && SMP
320
321config X86_32_LAZY_GS
322	def_bool y
323	depends on X86_32 && !CC_STACKPROTECTOR
324
325config ARCH_SUPPORTS_UPROBES
326	def_bool y
327
328config FIX_EARLYCON_MEM
329	def_bool y
330
331config PGTABLE_LEVELS
332	int
333	default 5 if X86_5LEVEL
334	default 4 if X86_64
335	default 3 if X86_PAE
336	default 2
337
338source "init/Kconfig"
339source "kernel/Kconfig.freezer"
340
341menu "Processor type and features"
342
343config ZONE_DMA
344	bool "DMA memory allocation support" if EXPERT
345	default y
346	help
347	  DMA memory allocation support allows devices with less than 32-bit
348	  addressing to allocate within the first 16MB of address space.
349	  Disable if no such devices will be used.
350
351	  If unsure, say Y.
352
353config SMP
354	bool "Symmetric multi-processing support"
355	---help---
356	  This enables support for systems with more than one CPU. If you have
357	  a system with only one CPU, say N. If you have a system with more
358	  than one CPU, say Y.
359
360	  If you say N here, the kernel will run on uni- and multiprocessor
361	  machines, but will use only one CPU of a multiprocessor machine. If
362	  you say Y here, the kernel will run on many, but not all,
363	  uniprocessor machines. On a uniprocessor machine, the kernel
364	  will run faster if you say N here.
365
366	  Note that if you say Y here and choose architecture "586" or
367	  "Pentium" under "Processor family", the kernel will not work on 486
368	  architectures. Similarly, multiprocessor kernels for the "PPro"
369	  architecture may not work on all Pentium based boards.
370
371	  People using multiprocessor machines who say Y here should also say
372	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
373	  Management" code will be disabled if you say Y here.
374
375	  See also <file:Documentation/x86/i386/IO-APIC.txt>,
376	  <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at
377	  <http://www.tldp.org/docs.html#howto>.
378
379	  If you don't know what to do here, say N.
380
381config X86_FEATURE_NAMES
382	bool "Processor feature human-readable names" if EMBEDDED
383	default y
384	---help---
385	  This option compiles in a table of x86 feature bits and corresponding
386	  names.  This is required to support /proc/cpuinfo and a few kernel
387	  messages.  You can disable this to save space, at the expense of
388	  making those few kernel messages show numeric feature bits instead.
389
390	  If in doubt, say Y.
391
392config X86_FAST_FEATURE_TESTS
393	bool "Fast CPU feature tests" if EMBEDDED
394	default y
395	---help---
396	  Some fast-paths in the kernel depend on the capabilities of the CPU.
397	  Say Y here for the kernel to patch in the appropriate code at runtime
398	  based on the capabilities of the CPU. The infrastructure for patching
399	  code at runtime takes up some additional space; space-constrained
400	  embedded systems may wish to say N here to produce smaller, slightly
401	  slower code.
402
403config X86_X2APIC
404	bool "Support x2apic"
405	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
406	---help---
407	  This enables x2apic support on CPUs that have this feature.
408
409	  This allows 32-bit apic IDs (so it can support very large systems),
410	  and accesses the local apic via MSRs not via mmio.
411
412	  If you don't know what to do here, say N.
413
414config X86_MPPARSE
415	bool "Enable MPS table" if ACPI || SFI
416	default y
417	depends on X86_LOCAL_APIC
418	---help---
419	  For old smp systems that do not have proper acpi support. Newer systems
420	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
421
422config X86_BIGSMP
423	bool "Support for big SMP systems with more than 8 CPUs"
424	depends on X86_32 && SMP
425	---help---
426	  This option is needed for the systems that have more than 8 CPUs
427
428config GOLDFISH
429       def_bool y
430       depends on X86_GOLDFISH
431
432config INTEL_RDT
433	bool "Intel Resource Director Technology support"
434	default n
435	depends on X86 && CPU_SUP_INTEL
436	select KERNFS
437	help
438	  Select to enable resource allocation and monitoring which are
439	  sub-features of Intel Resource Director Technology(RDT). More
440	  information about RDT can be found in the Intel x86
441	  Architecture Software Developer Manual.
442
443	  Say N if unsure.
444
445if X86_32
446config X86_EXTENDED_PLATFORM
447	bool "Support for extended (non-PC) x86 platforms"
448	default y
449	---help---
450	  If you disable this option then the kernel will only support
451	  standard PC platforms. (which covers the vast majority of
452	  systems out there.)
453
454	  If you enable this option then you'll be able to select support
455	  for the following (non-PC) 32 bit x86 platforms:
456		Goldfish (Android emulator)
457		AMD Elan
458		RDC R-321x SoC
459		SGI 320/540 (Visual Workstation)
460		STA2X11-based (e.g. Northville)
461		Moorestown MID devices
462
463	  If you have one of these systems, or if you want to build a
464	  generic distribution kernel, say Y here - otherwise say N.
465endif
466
467if X86_64
468config X86_EXTENDED_PLATFORM
469	bool "Support for extended (non-PC) x86 platforms"
470	default y
471	---help---
472	  If you disable this option then the kernel will only support
473	  standard PC platforms. (which covers the vast majority of
474	  systems out there.)
475
476	  If you enable this option then you'll be able to select support
477	  for the following (non-PC) 64 bit x86 platforms:
478		Numascale NumaChip
479		ScaleMP vSMP
480		SGI Ultraviolet
481
482	  If you have one of these systems, or if you want to build a
483	  generic distribution kernel, say Y here - otherwise say N.
484endif
485# This is an alphabetically sorted list of 64 bit extended platforms
486# Please maintain the alphabetic order if and when there are additions
487config X86_NUMACHIP
488	bool "Numascale NumaChip"
489	depends on X86_64
490	depends on X86_EXTENDED_PLATFORM
491	depends on NUMA
492	depends on SMP
493	depends on X86_X2APIC
494	depends on PCI_MMCONFIG
495	---help---
496	  Adds support for Numascale NumaChip large-SMP systems. Needed to
497	  enable more than ~168 cores.
498	  If you don't have one of these, you should say N here.
499
500config X86_VSMP
501	bool "ScaleMP vSMP"
502	select HYPERVISOR_GUEST
503	select PARAVIRT
504	depends on X86_64 && PCI
505	depends on X86_EXTENDED_PLATFORM
506	depends on SMP
507	---help---
508	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
509	  supposed to run on these EM64T-based machines.  Only choose this option
510	  if you have one of these machines.
511
512config X86_UV
513	bool "SGI Ultraviolet"
514	depends on X86_64
515	depends on X86_EXTENDED_PLATFORM
516	depends on NUMA
517	depends on EFI
518	depends on X86_X2APIC
519	depends on PCI
520	---help---
521	  This option is needed in order to support SGI Ultraviolet systems.
522	  If you don't have one of these, you should say N here.
523
524# Following is an alphabetically sorted list of 32 bit extended platforms
525# Please maintain the alphabetic order if and when there are additions
526
527config X86_GOLDFISH
528       bool "Goldfish (Virtual Platform)"
529       depends on X86_EXTENDED_PLATFORM
530       ---help---
531	 Enable support for the Goldfish virtual platform used primarily
532	 for Android development. Unless you are building for the Android
533	 Goldfish emulator say N here.
534
535config X86_INTEL_CE
536	bool "CE4100 TV platform"
537	depends on PCI
538	depends on PCI_GODIRECT
539	depends on X86_IO_APIC
540	depends on X86_32
541	depends on X86_EXTENDED_PLATFORM
542	select X86_REBOOTFIXUPS
543	select OF
544	select OF_EARLY_FLATTREE
545	---help---
546	  Select for the Intel CE media processor (CE4100) SOC.
547	  This option compiles in support for the CE4100 SOC for settop
548	  boxes and media devices.
549
550config X86_INTEL_MID
551	bool "Intel MID platform support"
552	depends on X86_EXTENDED_PLATFORM
553	depends on X86_PLATFORM_DEVICES
554	depends on PCI
555	depends on X86_64 || (PCI_GOANY && X86_32)
556	depends on X86_IO_APIC
557	select SFI
558	select I2C
559	select DW_APB_TIMER
560	select APB_TIMER
561	select INTEL_SCU_IPC
562	select MFD_INTEL_MSIC
563	---help---
564	  Select to build a kernel capable of supporting Intel MID (Mobile
565	  Internet Device) platform systems which do not have the PCI legacy
566	  interfaces. If you are building for a PC class system say N here.
567
568	  Intel MID platforms are based on an Intel processor and chipset which
569	  consume less power than most of the x86 derivatives.
570
571config X86_INTEL_QUARK
572	bool "Intel Quark platform support"
573	depends on X86_32
574	depends on X86_EXTENDED_PLATFORM
575	depends on X86_PLATFORM_DEVICES
576	depends on X86_TSC
577	depends on PCI
578	depends on PCI_GOANY
579	depends on X86_IO_APIC
580	select IOSF_MBI
581	select INTEL_IMR
582	select COMMON_CLK
583	---help---
584	  Select to include support for Quark X1000 SoC.
585	  Say Y here if you have a Quark based system such as the Arduino
586	  compatible Intel Galileo.
587
588config X86_INTEL_LPSS
589	bool "Intel Low Power Subsystem Support"
590	depends on X86 && ACPI
591	select COMMON_CLK
592	select PINCTRL
593	select IOSF_MBI
594	---help---
595	  Select to build support for Intel Low Power Subsystem such as
596	  found on Intel Lynxpoint PCH. Selecting this option enables
597	  things like clock tree (common clock framework) and pincontrol
598	  which are needed by the LPSS peripheral drivers.
599
600config X86_AMD_PLATFORM_DEVICE
601	bool "AMD ACPI2Platform devices support"
602	depends on ACPI
603	select COMMON_CLK
604	select PINCTRL
605	---help---
606	  Select to interpret AMD specific ACPI device to platform device
607	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
608	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
609	  implemented under PINCTRL subsystem.
610
611config IOSF_MBI
612	tristate "Intel SoC IOSF Sideband support for SoC platforms"
613	depends on PCI
614	---help---
615	  This option enables sideband register access support for Intel SoC
616	  platforms. On these platforms the IOSF sideband is used in lieu of
617	  MSR's for some register accesses, mostly but not limited to thermal
618	  and power. Drivers may query the availability of this device to
619	  determine if they need the sideband in order to work on these
620	  platforms. The sideband is available on the following SoC products.
621	  This list is not meant to be exclusive.
622	   - BayTrail
623	   - Braswell
624	   - Quark
625
626	  You should say Y if you are running a kernel on one of these SoC's.
627
628config IOSF_MBI_DEBUG
629	bool "Enable IOSF sideband access through debugfs"
630	depends on IOSF_MBI && DEBUG_FS
631	---help---
632	  Select this option to expose the IOSF sideband access registers (MCR,
633	  MDR, MCRX) through debugfs to write and read register information from
634	  different units on the SoC. This is most useful for obtaining device
635	  state information for debug and analysis. As this is a general access
636	  mechanism, users of this option would have specific knowledge of the
637	  device they want to access.
638
639	  If you don't require the option or are in doubt, say N.
640
641config X86_RDC321X
642	bool "RDC R-321x SoC"
643	depends on X86_32
644	depends on X86_EXTENDED_PLATFORM
645	select M486
646	select X86_REBOOTFIXUPS
647	---help---
648	  This option is needed for RDC R-321x system-on-chip, also known
649	  as R-8610-(G).
650	  If you don't have one of these chips, you should say N here.
651
652config X86_32_NON_STANDARD
653	bool "Support non-standard 32-bit SMP architectures"
654	depends on X86_32 && SMP
655	depends on X86_EXTENDED_PLATFORM
656	---help---
657	  This option compiles in the bigsmp and STA2X11 default
658	  subarchitectures.  It is intended for a generic binary
659	  kernel. If you select them all, kernel will probe it one by
660	  one and will fallback to default.
661
662# Alphabetically sorted list of Non standard 32 bit platforms
663
664config X86_SUPPORTS_MEMORY_FAILURE
665	def_bool y
666	# MCE code calls memory_failure():
667	depends on X86_MCE
668	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
669	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
670	depends on X86_64 || !SPARSEMEM
671	select ARCH_SUPPORTS_MEMORY_FAILURE
672
673config STA2X11
674	bool "STA2X11 Companion Chip Support"
675	depends on X86_32_NON_STANDARD && PCI
676	select X86_DEV_DMA_OPS
677	select X86_DMA_REMAP
678	select SWIOTLB
679	select MFD_STA2X11
680	select GPIOLIB
681	default n
682	---help---
683	  This adds support for boards based on the STA2X11 IO-Hub,
684	  a.k.a. "ConneXt". The chip is used in place of the standard
685	  PC chipset, so all "standard" peripherals are missing. If this
686	  option is selected the kernel will still be able to boot on
687	  standard PC machines.
688
689config X86_32_IRIS
690	tristate "Eurobraille/Iris poweroff module"
691	depends on X86_32
692	---help---
693	  The Iris machines from EuroBraille do not have APM or ACPI support
694	  to shut themselves down properly.  A special I/O sequence is
695	  needed to do so, which is what this module does at
696	  kernel shutdown.
697
698	  This is only for Iris machines from EuroBraille.
699
700	  If unused, say N.
701
702config SCHED_OMIT_FRAME_POINTER
703	def_bool y
704	prompt "Single-depth WCHAN output"
705	depends on X86
706	---help---
707	  Calculate simpler /proc/<PID>/wchan values. If this option
708	  is disabled then wchan values will recurse back to the
709	  caller function. This provides more accurate wchan values,
710	  at the expense of slightly more scheduling overhead.
711
712	  If in doubt, say "Y".
713
714menuconfig HYPERVISOR_GUEST
715	bool "Linux guest support"
716	---help---
717	  Say Y here to enable options for running Linux under various hyper-
718	  visors. This option enables basic hypervisor detection and platform
719	  setup.
720
721	  If you say N, all options in this submenu will be skipped and
722	  disabled, and Linux guest support won't be built in.
723
724if HYPERVISOR_GUEST
725
726config PARAVIRT
727	bool "Enable paravirtualization code"
728	---help---
729	  This changes the kernel so it can modify itself when it is run
730	  under a hypervisor, potentially improving performance significantly
731	  over full virtualization.  However, when run without a hypervisor
732	  the kernel is theoretically slower and slightly larger.
733
734config PARAVIRT_DEBUG
735	bool "paravirt-ops debugging"
736	depends on PARAVIRT && DEBUG_KERNEL
737	---help---
738	  Enable to debug paravirt_ops internals.  Specifically, BUG if
739	  a paravirt_op is missing when it is called.
740
741config PARAVIRT_SPINLOCKS
742	bool "Paravirtualization layer for spinlocks"
743	depends on PARAVIRT && SMP
744	---help---
745	  Paravirtualized spinlocks allow a pvops backend to replace the
746	  spinlock implementation with something virtualization-friendly
747	  (for example, block the virtual CPU rather than spinning).
748
749	  It has a minimal impact on native kernels and gives a nice performance
750	  benefit on paravirtualized KVM / Xen kernels.
751
752	  If you are unsure how to answer this question, answer Y.
753
754config QUEUED_LOCK_STAT
755	bool "Paravirt queued spinlock statistics"
756	depends on PARAVIRT_SPINLOCKS && DEBUG_FS
757	---help---
758	  Enable the collection of statistical data on the slowpath
759	  behavior of paravirtualized queued spinlocks and report
760	  them on debugfs.
761
762source "arch/x86/xen/Kconfig"
763
764config KVM_GUEST
765	bool "KVM Guest support (including kvmclock)"
766	depends on PARAVIRT
767	select PARAVIRT_CLOCK
768	default y
769	---help---
770	  This option enables various optimizations for running under the KVM
771	  hypervisor. It includes a paravirtualized clock, so that instead
772	  of relying on a PIT (or probably other) emulation by the
773	  underlying device model, the host provides the guest with
774	  timing infrastructure such as time of day, and system time
775
776config KVM_DEBUG_FS
777	bool "Enable debug information for KVM Guests in debugfs"
778	depends on KVM_GUEST && DEBUG_FS
779	default n
780	---help---
781	  This option enables collection of various statistics for KVM guest.
782	  Statistics are displayed in debugfs filesystem. Enabling this option
783	  may incur significant overhead.
784
785config PARAVIRT_TIME_ACCOUNTING
786	bool "Paravirtual steal time accounting"
787	depends on PARAVIRT
788	default n
789	---help---
790	  Select this option to enable fine granularity task steal time
791	  accounting. Time spent executing other tasks in parallel with
792	  the current vCPU is discounted from the vCPU power. To account for
793	  that, there can be a small performance impact.
794
795	  If in doubt, say N here.
796
797config PARAVIRT_CLOCK
798	bool
799
800endif #HYPERVISOR_GUEST
801
802config NO_BOOTMEM
803	def_bool y
804
805source "arch/x86/Kconfig.cpu"
806
807config HPET_TIMER
808	def_bool X86_64
809	prompt "HPET Timer Support" if X86_32
810	---help---
811	  Use the IA-PC HPET (High Precision Event Timer) to manage
812	  time in preference to the PIT and RTC, if a HPET is
813	  present.
814	  HPET is the next generation timer replacing legacy 8254s.
815	  The HPET provides a stable time base on SMP
816	  systems, unlike the TSC, but it is more expensive to access,
817	  as it is off-chip.  The interface used is documented
818	  in the HPET spec, revision 1.
819
820	  You can safely choose Y here.  However, HPET will only be
821	  activated if the platform and the BIOS support this feature.
822	  Otherwise the 8254 will be used for timing services.
823
824	  Choose N to continue using the legacy 8254 timer.
825
826config HPET_EMULATE_RTC
827	def_bool y
828	depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
829
830config APB_TIMER
831       def_bool y if X86_INTEL_MID
832       prompt "Intel MID APB Timer Support" if X86_INTEL_MID
833       select DW_APB_TIMER
834       depends on X86_INTEL_MID && SFI
835       help
836         APB timer is the replacement for 8254, HPET on X86 MID platforms.
837         The APBT provides a stable time base on SMP
838         systems, unlike the TSC, but it is more expensive to access,
839         as it is off-chip. APB timers are always running regardless of CPU
840         C states, they are used as per CPU clockevent device when possible.
841
842# Mark as expert because too many people got it wrong.
843# The code disables itself when not needed.
844config DMI
845	default y
846	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
847	bool "Enable DMI scanning" if EXPERT
848	---help---
849	  Enabled scanning of DMI to identify machine quirks. Say Y
850	  here unless you have verified that your setup is not
851	  affected by entries in the DMI blacklist. Required by PNP
852	  BIOS code.
853
854config GART_IOMMU
855	bool "Old AMD GART IOMMU support"
856	select SWIOTLB
857	depends on X86_64 && PCI && AMD_NB
858	---help---
859	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
860	  GART based hardware IOMMUs.
861
862	  The GART supports full DMA access for devices with 32-bit access
863	  limitations, on systems with more than 3 GB. This is usually needed
864	  for USB, sound, many IDE/SATA chipsets and some other devices.
865
866	  Newer systems typically have a modern AMD IOMMU, supported via
867	  the CONFIG_AMD_IOMMU=y config option.
868
869	  In normal configurations this driver is only active when needed:
870	  there's more than 3 GB of memory and the system contains a
871	  32-bit limited device.
872
873	  If unsure, say Y.
874
875config CALGARY_IOMMU
876	bool "IBM Calgary IOMMU support"
877	select SWIOTLB
878	depends on X86_64 && PCI
879	---help---
880	  Support for hardware IOMMUs in IBM's xSeries x366 and x460
881	  systems. Needed to run systems with more than 3GB of memory
882	  properly with 32-bit PCI devices that do not support DAC
883	  (Double Address Cycle). Calgary also supports bus level
884	  isolation, where all DMAs pass through the IOMMU.  This
885	  prevents them from going anywhere except their intended
886	  destination. This catches hard-to-find kernel bugs and
887	  mis-behaving drivers and devices that do not use the DMA-API
888	  properly to set up their DMA buffers.  The IOMMU can be
889	  turned off at boot time with the iommu=off parameter.
890	  Normally the kernel will make the right choice by itself.
891	  If unsure, say Y.
892
893config CALGARY_IOMMU_ENABLED_BY_DEFAULT
894	def_bool y
895	prompt "Should Calgary be enabled by default?"
896	depends on CALGARY_IOMMU
897	---help---
898	  Should Calgary be enabled by default? if you choose 'y', Calgary
899	  will be used (if it exists). If you choose 'n', Calgary will not be
900	  used even if it exists. If you choose 'n' and would like to use
901	  Calgary anyway, pass 'iommu=calgary' on the kernel command line.
902	  If unsure, say Y.
903
904# need this always selected by IOMMU for the VIA workaround
905config SWIOTLB
906	def_bool y if X86_64
907	---help---
908	  Support for software bounce buffers used on x86-64 systems
909	  which don't have a hardware IOMMU. Using this PCI devices
910	  which can only access 32-bits of memory can be used on systems
911	  with more than 3 GB of memory.
912	  If unsure, say Y.
913
914config IOMMU_HELPER
915	def_bool y
916	depends on CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU
917
918config MAXSMP
919	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
920	depends on X86_64 && SMP && DEBUG_KERNEL
921	select CPUMASK_OFFSTACK
922	---help---
923	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
924	  If unsure, say N.
925
926config NR_CPUS
927	int "Maximum number of CPUs" if SMP && !MAXSMP
928	range 2 8 if SMP && X86_32 && !X86_BIGSMP
929	range 2 64 if SMP && X86_32 && X86_BIGSMP
930	range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK && X86_64
931	range 2 8192 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64
932	default "1" if !SMP
933	default "8192" if MAXSMP
934	default "32" if SMP && X86_BIGSMP
935	default "8" if SMP && X86_32
936	default "64" if SMP
937	---help---
938	  This allows you to specify the maximum number of CPUs which this
939	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
940	  supported value is 8192, otherwise the maximum value is 512.  The
941	  minimum value which makes sense is 2.
942
943	  This is purely to save memory - each supported CPU adds
944	  approximately eight kilobytes to the kernel image.
945
946config SCHED_SMT
947	bool "SMT (Hyperthreading) scheduler support"
948	depends on SMP
949	---help---
950	  SMT scheduler support improves the CPU scheduler's decision making
951	  when dealing with Intel Pentium 4 chips with HyperThreading at a
952	  cost of slightly increased overhead in some places. If unsure say
953	  N here.
954
955config SCHED_MC
956	def_bool y
957	prompt "Multi-core scheduler support"
958	depends on SMP
959	---help---
960	  Multi-core scheduler support improves the CPU scheduler's decision
961	  making when dealing with multi-core CPU chips at a cost of slightly
962	  increased overhead in some places. If unsure say N here.
963
964config SCHED_MC_PRIO
965	bool "CPU core priorities scheduler support"
966	depends on SCHED_MC && CPU_SUP_INTEL
967	select X86_INTEL_PSTATE
968	select CPU_FREQ
969	default y
970	---help---
971	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
972	  core ordering determined at manufacturing time, which allows
973	  certain cores to reach higher turbo frequencies (when running
974	  single threaded workloads) than others.
975
976	  Enabling this kernel feature teaches the scheduler about
977	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
978	  scheduler's CPU selection logic accordingly, so that higher
979	  overall system performance can be achieved.
980
981	  This feature will have no effect on CPUs without this feature.
982
983	  If unsure say Y here.
984
985source "kernel/Kconfig.preempt"
986
987config UP_LATE_INIT
988       def_bool y
989       depends on !SMP && X86_LOCAL_APIC
990
991config X86_UP_APIC
992	bool "Local APIC support on uniprocessors" if !PCI_MSI
993	default PCI_MSI
994	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
995	---help---
996	  A local APIC (Advanced Programmable Interrupt Controller) is an
997	  integrated interrupt controller in the CPU. If you have a single-CPU
998	  system which has a processor with a local APIC, you can say Y here to
999	  enable and use it. If you say Y here even though your machine doesn't
1000	  have a local APIC, then the kernel will still run with no slowdown at
1001	  all. The local APIC supports CPU-generated self-interrupts (timer,
1002	  performance counters), and the NMI watchdog which detects hard
1003	  lockups.
1004
1005config X86_UP_IOAPIC
1006	bool "IO-APIC support on uniprocessors"
1007	depends on X86_UP_APIC
1008	---help---
1009	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1010	  SMP-capable replacement for PC-style interrupt controllers. Most
1011	  SMP systems and many recent uniprocessor systems have one.
1012
1013	  If you have a single-CPU system with an IO-APIC, you can say Y here
1014	  to use it. If you say Y here even though your machine doesn't have
1015	  an IO-APIC, then the kernel will still run with no slowdown at all.
1016
1017config X86_LOCAL_APIC
1018	def_bool y
1019	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1020	select IRQ_DOMAIN_HIERARCHY
1021	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1022
1023config X86_IO_APIC
1024	def_bool y
1025	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1026
1027config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1028	bool "Reroute for broken boot IRQs"
1029	depends on X86_IO_APIC
1030	---help---
1031	  This option enables a workaround that fixes a source of
1032	  spurious interrupts. This is recommended when threaded
1033	  interrupt handling is used on systems where the generation of
1034	  superfluous "boot interrupts" cannot be disabled.
1035
1036	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1037	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1038	  kernel does during interrupt handling). On chipsets where this
1039	  boot IRQ generation cannot be disabled, this workaround keeps
1040	  the original IRQ line masked so that only the equivalent "boot
1041	  IRQ" is delivered to the CPUs. The workaround also tells the
1042	  kernel to set up the IRQ handler on the boot IRQ line. In this
1043	  way only one interrupt is delivered to the kernel. Otherwise
1044	  the spurious second interrupt may cause the kernel to bring
1045	  down (vital) interrupt lines.
1046
1047	  Only affects "broken" chipsets. Interrupt sharing may be
1048	  increased on these systems.
1049
1050config X86_MCE
1051	bool "Machine Check / overheating reporting"
1052	select GENERIC_ALLOCATOR
1053	default y
1054	---help---
1055	  Machine Check support allows the processor to notify the
1056	  kernel if it detects a problem (e.g. overheating, data corruption).
1057	  The action the kernel takes depends on the severity of the problem,
1058	  ranging from warning messages to halting the machine.
1059
1060config X86_MCELOG_LEGACY
1061	bool "Support for deprecated /dev/mcelog character device"
1062	depends on X86_MCE
1063	---help---
1064	  Enable support for /dev/mcelog which is needed by the old mcelog
1065	  userspace logging daemon. Consider switching to the new generation
1066	  rasdaemon solution.
1067
1068config X86_MCE_INTEL
1069	def_bool y
1070	prompt "Intel MCE features"
1071	depends on X86_MCE && X86_LOCAL_APIC
1072	---help---
1073	   Additional support for intel specific MCE features such as
1074	   the thermal monitor.
1075
1076config X86_MCE_AMD
1077	def_bool y
1078	prompt "AMD MCE features"
1079	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1080	---help---
1081	   Additional support for AMD specific MCE features such as
1082	   the DRAM Error Threshold.
1083
1084config X86_ANCIENT_MCE
1085	bool "Support for old Pentium 5 / WinChip machine checks"
1086	depends on X86_32 && X86_MCE
1087	---help---
1088	  Include support for machine check handling on old Pentium 5 or WinChip
1089	  systems. These typically need to be enabled explicitly on the command
1090	  line.
1091
1092config X86_MCE_THRESHOLD
1093	depends on X86_MCE_AMD || X86_MCE_INTEL
1094	def_bool y
1095
1096config X86_MCE_INJECT
1097	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1098	tristate "Machine check injector support"
1099	---help---
1100	  Provide support for injecting machine checks for testing purposes.
1101	  If you don't know what a machine check is and you don't do kernel
1102	  QA it is safe to say n.
1103
1104config X86_THERMAL_VECTOR
1105	def_bool y
1106	depends on X86_MCE_INTEL
1107
1108source "arch/x86/events/Kconfig"
1109
1110config X86_LEGACY_VM86
1111	bool "Legacy VM86 support"
1112	default n
1113	depends on X86_32
1114	---help---
1115	  This option allows user programs to put the CPU into V8086
1116	  mode, which is an 80286-era approximation of 16-bit real mode.
1117
1118	  Some very old versions of X and/or vbetool require this option
1119	  for user mode setting.  Similarly, DOSEMU will use it if
1120	  available to accelerate real mode DOS programs.  However, any
1121	  recent version of DOSEMU, X, or vbetool should be fully
1122	  functional even without kernel VM86 support, as they will all
1123	  fall back to software emulation. Nevertheless, if you are using
1124	  a 16-bit DOS program where 16-bit performance matters, vm86
1125	  mode might be faster than emulation and you might want to
1126	  enable this option.
1127
1128	  Note that any app that works on a 64-bit kernel is unlikely to
1129	  need this option, as 64-bit kernels don't, and can't, support
1130	  V8086 mode. This option is also unrelated to 16-bit protected
1131	  mode and is not needed to run most 16-bit programs under Wine.
1132
1133	  Enabling this option increases the complexity of the kernel
1134	  and slows down exception handling a tiny bit.
1135
1136	  If unsure, say N here.
1137
1138config VM86
1139       bool
1140       default X86_LEGACY_VM86
1141
1142config X86_16BIT
1143	bool "Enable support for 16-bit segments" if EXPERT
1144	default y
1145	depends on MODIFY_LDT_SYSCALL
1146	---help---
1147	  This option is required by programs like Wine to run 16-bit
1148	  protected mode legacy code on x86 processors.  Disabling
1149	  this option saves about 300 bytes on i386, or around 6K text
1150	  plus 16K runtime memory on x86-64,
1151
1152config X86_ESPFIX32
1153	def_bool y
1154	depends on X86_16BIT && X86_32
1155
1156config X86_ESPFIX64
1157	def_bool y
1158	depends on X86_16BIT && X86_64
1159
1160config X86_VSYSCALL_EMULATION
1161       bool "Enable vsyscall emulation" if EXPERT
1162       default y
1163       depends on X86_64
1164       ---help---
1165	 This enables emulation of the legacy vsyscall page.  Disabling
1166	 it is roughly equivalent to booting with vsyscall=none, except
1167	 that it will also disable the helpful warning if a program
1168	 tries to use a vsyscall.  With this option set to N, offending
1169	 programs will just segfault, citing addresses of the form
1170	 0xffffffffff600?00.
1171
1172	 This option is required by many programs built before 2013, and
1173	 care should be used even with newer programs if set to N.
1174
1175	 Disabling this option saves about 7K of kernel size and
1176	 possibly 4K of additional runtime pagetable memory.
1177
1178config TOSHIBA
1179	tristate "Toshiba Laptop support"
1180	depends on X86_32
1181	---help---
1182	  This adds a driver to safely access the System Management Mode of
1183	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1184	  not work on models with a Phoenix BIOS. The System Management Mode
1185	  is used to set the BIOS and power saving options on Toshiba portables.
1186
1187	  For information on utilities to make use of this driver see the
1188	  Toshiba Linux utilities web site at:
1189	  <http://www.buzzard.org.uk/toshiba/>.
1190
1191	  Say Y if you intend to run this kernel on a Toshiba portable.
1192	  Say N otherwise.
1193
1194config I8K
1195	tristate "Dell i8k legacy laptop support"
1196	select HWMON
1197	select SENSORS_DELL_SMM
1198	---help---
1199	  This option enables legacy /proc/i8k userspace interface in hwmon
1200	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1201	  temperature and allows controlling fan speeds of Dell laptops via
1202	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1203	  it reports also power and hotkey status. For fan speed control is
1204	  needed userspace package i8kutils.
1205
1206	  Say Y if you intend to run this kernel on old Dell laptops or want to
1207	  use userspace package i8kutils.
1208	  Say N otherwise.
1209
1210config X86_REBOOTFIXUPS
1211	bool "Enable X86 board specific fixups for reboot"
1212	depends on X86_32
1213	---help---
1214	  This enables chipset and/or board specific fixups to be done
1215	  in order to get reboot to work correctly. This is only needed on
1216	  some combinations of hardware and BIOS. The symptom, for which
1217	  this config is intended, is when reboot ends with a stalled/hung
1218	  system.
1219
1220	  Currently, the only fixup is for the Geode machines using
1221	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1222
1223	  Say Y if you want to enable the fixup. Currently, it's safe to
1224	  enable this option even if you don't need it.
1225	  Say N otherwise.
1226
1227config MICROCODE
1228	bool "CPU microcode loading support"
1229	default y
1230	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1231	select FW_LOADER
1232	---help---
1233	  If you say Y here, you will be able to update the microcode on
1234	  Intel and AMD processors. The Intel support is for the IA32 family,
1235	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1236	  AMD support is for families 0x10 and later. You will obviously need
1237	  the actual microcode binary data itself which is not shipped with
1238	  the Linux kernel.
1239
1240	  The preferred method to load microcode from a detached initrd is described
1241	  in Documentation/x86/early-microcode.txt. For that you need to enable
1242	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1243	  initrd for microcode blobs.
1244
1245	  In addition, you can build-in the microcode into the kernel. For that you
1246	  need to enable FIRMWARE_IN_KERNEL and add the vendor-supplied microcode
1247	  to the CONFIG_EXTRA_FIRMWARE config option.
1248
1249config MICROCODE_INTEL
1250	bool "Intel microcode loading support"
1251	depends on MICROCODE
1252	default MICROCODE
1253	select FW_LOADER
1254	---help---
1255	  This options enables microcode patch loading support for Intel
1256	  processors.
1257
1258	  For the current Intel microcode data package go to
1259	  <https://downloadcenter.intel.com> and search for
1260	  'Linux Processor Microcode Data File'.
1261
1262config MICROCODE_AMD
1263	bool "AMD microcode loading support"
1264	depends on MICROCODE
1265	select FW_LOADER
1266	---help---
1267	  If you select this option, microcode patch loading support for AMD
1268	  processors will be enabled.
1269
1270config MICROCODE_OLD_INTERFACE
1271	def_bool y
1272	depends on MICROCODE
1273
1274config X86_MSR
1275	tristate "/dev/cpu/*/msr - Model-specific register support"
1276	---help---
1277	  This device gives privileged processes access to the x86
1278	  Model-Specific Registers (MSRs).  It is a character device with
1279	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1280	  MSR accesses are directed to a specific CPU on multi-processor
1281	  systems.
1282
1283config X86_CPUID
1284	tristate "/dev/cpu/*/cpuid - CPU information support"
1285	---help---
1286	  This device gives processes access to the x86 CPUID instruction to
1287	  be executed on a specific processor.  It is a character device
1288	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1289	  /dev/cpu/31/cpuid.
1290
1291choice
1292	prompt "High Memory Support"
1293	default HIGHMEM4G
1294	depends on X86_32
1295
1296config NOHIGHMEM
1297	bool "off"
1298	---help---
1299	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1300	  However, the address space of 32-bit x86 processors is only 4
1301	  Gigabytes large. That means that, if you have a large amount of
1302	  physical memory, not all of it can be "permanently mapped" by the
1303	  kernel. The physical memory that's not permanently mapped is called
1304	  "high memory".
1305
1306	  If you are compiling a kernel which will never run on a machine with
1307	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1308	  choice and suitable for most users). This will result in a "3GB/1GB"
1309	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1310	  space and the remaining part of the 4GB virtual memory space is used
1311	  by the kernel to permanently map as much physical memory as
1312	  possible.
1313
1314	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1315	  answer "4GB" here.
1316
1317	  If more than 4 Gigabytes is used then answer "64GB" here. This
1318	  selection turns Intel PAE (Physical Address Extension) mode on.
1319	  PAE implements 3-level paging on IA32 processors. PAE is fully
1320	  supported by Linux, PAE mode is implemented on all recent Intel
1321	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1322	  then the kernel will not boot on CPUs that don't support PAE!
1323
1324	  The actual amount of total physical memory will either be
1325	  auto detected or can be forced by using a kernel command line option
1326	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1327	  your boot loader (lilo or loadlin) about how to pass options to the
1328	  kernel at boot time.)
1329
1330	  If unsure, say "off".
1331
1332config HIGHMEM4G
1333	bool "4GB"
1334	---help---
1335	  Select this if you have a 32-bit processor and between 1 and 4
1336	  gigabytes of physical RAM.
1337
1338config HIGHMEM64G
1339	bool "64GB"
1340	depends on !M486
1341	select X86_PAE
1342	---help---
1343	  Select this if you have a 32-bit processor and more than 4
1344	  gigabytes of physical RAM.
1345
1346endchoice
1347
1348choice
1349	prompt "Memory split" if EXPERT
1350	default VMSPLIT_3G
1351	depends on X86_32
1352	---help---
1353	  Select the desired split between kernel and user memory.
1354
1355	  If the address range available to the kernel is less than the
1356	  physical memory installed, the remaining memory will be available
1357	  as "high memory". Accessing high memory is a little more costly
1358	  than low memory, as it needs to be mapped into the kernel first.
1359	  Note that increasing the kernel address space limits the range
1360	  available to user programs, making the address space there
1361	  tighter.  Selecting anything other than the default 3G/1G split
1362	  will also likely make your kernel incompatible with binary-only
1363	  kernel modules.
1364
1365	  If you are not absolutely sure what you are doing, leave this
1366	  option alone!
1367
1368	config VMSPLIT_3G
1369		bool "3G/1G user/kernel split"
1370	config VMSPLIT_3G_OPT
1371		depends on !X86_PAE
1372		bool "3G/1G user/kernel split (for full 1G low memory)"
1373	config VMSPLIT_2G
1374		bool "2G/2G user/kernel split"
1375	config VMSPLIT_2G_OPT
1376		depends on !X86_PAE
1377		bool "2G/2G user/kernel split (for full 2G low memory)"
1378	config VMSPLIT_1G
1379		bool "1G/3G user/kernel split"
1380endchoice
1381
1382config PAGE_OFFSET
1383	hex
1384	default 0xB0000000 if VMSPLIT_3G_OPT
1385	default 0x80000000 if VMSPLIT_2G
1386	default 0x78000000 if VMSPLIT_2G_OPT
1387	default 0x40000000 if VMSPLIT_1G
1388	default 0xC0000000
1389	depends on X86_32
1390
1391config HIGHMEM
1392	def_bool y
1393	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1394
1395config X86_PAE
1396	bool "PAE (Physical Address Extension) Support"
1397	depends on X86_32 && !HIGHMEM4G
1398	select SWIOTLB
1399	---help---
1400	  PAE is required for NX support, and furthermore enables
1401	  larger swapspace support for non-overcommit purposes. It
1402	  has the cost of more pagetable lookup overhead, and also
1403	  consumes more pagetable space per process.
1404
1405config X86_5LEVEL
1406	bool "Enable 5-level page tables support"
1407	depends on X86_64
1408	---help---
1409	  5-level paging enables access to larger address space:
1410	  upto 128 PiB of virtual address space and 4 PiB of
1411	  physical address space.
1412
1413	  It will be supported by future Intel CPUs.
1414
1415	  Note: a kernel with this option enabled can only be booted
1416	  on machines that support the feature.
1417
1418	  See Documentation/x86/x86_64/5level-paging.txt for more
1419	  information.
1420
1421	  Say N if unsure.
1422
1423config ARCH_PHYS_ADDR_T_64BIT
1424	def_bool y
1425	depends on X86_64 || X86_PAE
1426
1427config ARCH_DMA_ADDR_T_64BIT
1428	def_bool y
1429	depends on X86_64 || HIGHMEM64G
1430
1431config X86_DIRECT_GBPAGES
1432	def_bool y
1433	depends on X86_64 && !DEBUG_PAGEALLOC
1434	---help---
1435	  Certain kernel features effectively disable kernel
1436	  linear 1 GB mappings (even if the CPU otherwise
1437	  supports them), so don't confuse the user by printing
1438	  that we have them enabled.
1439
1440config ARCH_HAS_MEM_ENCRYPT
1441	def_bool y
1442
1443config AMD_MEM_ENCRYPT
1444	bool "AMD Secure Memory Encryption (SME) support"
1445	depends on X86_64 && CPU_SUP_AMD
1446	---help---
1447	  Say yes to enable support for the encryption of system memory.
1448	  This requires an AMD processor that supports Secure Memory
1449	  Encryption (SME).
1450
1451config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1452	bool "Activate AMD Secure Memory Encryption (SME) by default"
1453	default y
1454	depends on AMD_MEM_ENCRYPT
1455	---help---
1456	  Say yes to have system memory encrypted by default if running on
1457	  an AMD processor that supports Secure Memory Encryption (SME).
1458
1459	  If set to Y, then the encryption of system memory can be
1460	  deactivated with the mem_encrypt=off command line option.
1461
1462	  If set to N, then the encryption of system memory can be
1463	  activated with the mem_encrypt=on command line option.
1464
1465config ARCH_USE_MEMREMAP_PROT
1466	def_bool y
1467	depends on AMD_MEM_ENCRYPT
1468
1469# Common NUMA Features
1470config NUMA
1471	bool "Numa Memory Allocation and Scheduler Support"
1472	depends on SMP
1473	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1474	default y if X86_BIGSMP
1475	---help---
1476	  Enable NUMA (Non Uniform Memory Access) support.
1477
1478	  The kernel will try to allocate memory used by a CPU on the
1479	  local memory controller of the CPU and add some more
1480	  NUMA awareness to the kernel.
1481
1482	  For 64-bit this is recommended if the system is Intel Core i7
1483	  (or later), AMD Opteron, or EM64T NUMA.
1484
1485	  For 32-bit this is only needed if you boot a 32-bit
1486	  kernel on a 64-bit NUMA platform.
1487
1488	  Otherwise, you should say N.
1489
1490config AMD_NUMA
1491	def_bool y
1492	prompt "Old style AMD Opteron NUMA detection"
1493	depends on X86_64 && NUMA && PCI
1494	---help---
1495	  Enable AMD NUMA node topology detection.  You should say Y here if
1496	  you have a multi processor AMD system. This uses an old method to
1497	  read the NUMA configuration directly from the builtin Northbridge
1498	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1499	  which also takes priority if both are compiled in.
1500
1501config X86_64_ACPI_NUMA
1502	def_bool y
1503	prompt "ACPI NUMA detection"
1504	depends on X86_64 && NUMA && ACPI && PCI
1505	select ACPI_NUMA
1506	---help---
1507	  Enable ACPI SRAT based node topology detection.
1508
1509# Some NUMA nodes have memory ranges that span
1510# other nodes.  Even though a pfn is valid and
1511# between a node's start and end pfns, it may not
1512# reside on that node.  See memmap_init_zone()
1513# for details.
1514config NODES_SPAN_OTHER_NODES
1515	def_bool y
1516	depends on X86_64_ACPI_NUMA
1517
1518config NUMA_EMU
1519	bool "NUMA emulation"
1520	depends on NUMA
1521	---help---
1522	  Enable NUMA emulation. A flat machine will be split
1523	  into virtual nodes when booted with "numa=fake=N", where N is the
1524	  number of nodes. This is only useful for debugging.
1525
1526config NODES_SHIFT
1527	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1528	range 1 10
1529	default "10" if MAXSMP
1530	default "6" if X86_64
1531	default "3"
1532	depends on NEED_MULTIPLE_NODES
1533	---help---
1534	  Specify the maximum number of NUMA Nodes available on the target
1535	  system.  Increases memory reserved to accommodate various tables.
1536
1537config ARCH_HAVE_MEMORY_PRESENT
1538	def_bool y
1539	depends on X86_32 && DISCONTIGMEM
1540
1541config NEED_NODE_MEMMAP_SIZE
1542	def_bool y
1543	depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1544
1545config ARCH_FLATMEM_ENABLE
1546	def_bool y
1547	depends on X86_32 && !NUMA
1548
1549config ARCH_DISCONTIGMEM_ENABLE
1550	def_bool y
1551	depends on NUMA && X86_32
1552
1553config ARCH_DISCONTIGMEM_DEFAULT
1554	def_bool y
1555	depends on NUMA && X86_32
1556
1557config ARCH_SPARSEMEM_ENABLE
1558	def_bool y
1559	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1560	select SPARSEMEM_STATIC if X86_32
1561	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1562
1563config ARCH_SPARSEMEM_DEFAULT
1564	def_bool y
1565	depends on X86_64
1566
1567config ARCH_SELECT_MEMORY_MODEL
1568	def_bool y
1569	depends on ARCH_SPARSEMEM_ENABLE
1570
1571config ARCH_MEMORY_PROBE
1572	bool "Enable sysfs memory/probe interface"
1573	depends on X86_64 && MEMORY_HOTPLUG
1574	help
1575	  This option enables a sysfs memory/probe interface for testing.
1576	  See Documentation/memory-hotplug.txt for more information.
1577	  If you are unsure how to answer this question, answer N.
1578
1579config ARCH_PROC_KCORE_TEXT
1580	def_bool y
1581	depends on X86_64 && PROC_KCORE
1582
1583config ILLEGAL_POINTER_VALUE
1584       hex
1585       default 0 if X86_32
1586       default 0xdead000000000000 if X86_64
1587
1588source "mm/Kconfig"
1589
1590config X86_PMEM_LEGACY_DEVICE
1591	bool
1592
1593config X86_PMEM_LEGACY
1594	tristate "Support non-standard NVDIMMs and ADR protected memory"
1595	depends on PHYS_ADDR_T_64BIT
1596	depends on BLK_DEV
1597	select X86_PMEM_LEGACY_DEVICE
1598	select LIBNVDIMM
1599	help
1600	  Treat memory marked using the non-standard e820 type of 12 as used
1601	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1602	  The kernel will offer these regions to the 'pmem' driver so
1603	  they can be used for persistent storage.
1604
1605	  Say Y if unsure.
1606
1607config HIGHPTE
1608	bool "Allocate 3rd-level pagetables from highmem"
1609	depends on HIGHMEM
1610	---help---
1611	  The VM uses one page table entry for each page of physical memory.
1612	  For systems with a lot of RAM, this can be wasteful of precious
1613	  low memory.  Setting this option will put user-space page table
1614	  entries in high memory.
1615
1616config X86_CHECK_BIOS_CORRUPTION
1617	bool "Check for low memory corruption"
1618	---help---
1619	  Periodically check for memory corruption in low memory, which
1620	  is suspected to be caused by BIOS.  Even when enabled in the
1621	  configuration, it is disabled at runtime.  Enable it by
1622	  setting "memory_corruption_check=1" on the kernel command
1623	  line.  By default it scans the low 64k of memory every 60
1624	  seconds; see the memory_corruption_check_size and
1625	  memory_corruption_check_period parameters in
1626	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1627
1628	  When enabled with the default parameters, this option has
1629	  almost no overhead, as it reserves a relatively small amount
1630	  of memory and scans it infrequently.  It both detects corruption
1631	  and prevents it from affecting the running system.
1632
1633	  It is, however, intended as a diagnostic tool; if repeatable
1634	  BIOS-originated corruption always affects the same memory,
1635	  you can use memmap= to prevent the kernel from using that
1636	  memory.
1637
1638config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1639	bool "Set the default setting of memory_corruption_check"
1640	depends on X86_CHECK_BIOS_CORRUPTION
1641	default y
1642	---help---
1643	  Set whether the default state of memory_corruption_check is
1644	  on or off.
1645
1646config X86_RESERVE_LOW
1647	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1648	default 64
1649	range 4 640
1650	---help---
1651	  Specify the amount of low memory to reserve for the BIOS.
1652
1653	  The first page contains BIOS data structures that the kernel
1654	  must not use, so that page must always be reserved.
1655
1656	  By default we reserve the first 64K of physical RAM, as a
1657	  number of BIOSes are known to corrupt that memory range
1658	  during events such as suspend/resume or monitor cable
1659	  insertion, so it must not be used by the kernel.
1660
1661	  You can set this to 4 if you are absolutely sure that you
1662	  trust the BIOS to get all its memory reservations and usages
1663	  right.  If you know your BIOS have problems beyond the
1664	  default 64K area, you can set this to 640 to avoid using the
1665	  entire low memory range.
1666
1667	  If you have doubts about the BIOS (e.g. suspend/resume does
1668	  not work or there's kernel crashes after certain hardware
1669	  hotplug events) then you might want to enable
1670	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1671	  typical corruption patterns.
1672
1673	  Leave this to the default value of 64 if you are unsure.
1674
1675config MATH_EMULATION
1676	bool
1677	depends on MODIFY_LDT_SYSCALL
1678	prompt "Math emulation" if X86_32
1679	---help---
1680	  Linux can emulate a math coprocessor (used for floating point
1681	  operations) if you don't have one. 486DX and Pentium processors have
1682	  a math coprocessor built in, 486SX and 386 do not, unless you added
1683	  a 487DX or 387, respectively. (The messages during boot time can
1684	  give you some hints here ["man dmesg"].) Everyone needs either a
1685	  coprocessor or this emulation.
1686
1687	  If you don't have a math coprocessor, you need to say Y here; if you
1688	  say Y here even though you have a coprocessor, the coprocessor will
1689	  be used nevertheless. (This behavior can be changed with the kernel
1690	  command line option "no387", which comes handy if your coprocessor
1691	  is broken. Try "man bootparam" or see the documentation of your boot
1692	  loader (lilo or loadlin) about how to pass options to the kernel at
1693	  boot time.) This means that it is a good idea to say Y here if you
1694	  intend to use this kernel on different machines.
1695
1696	  More information about the internals of the Linux math coprocessor
1697	  emulation can be found in <file:arch/x86/math-emu/README>.
1698
1699	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1700	  kernel, it won't hurt.
1701
1702config MTRR
1703	def_bool y
1704	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1705	---help---
1706	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1707	  the Memory Type Range Registers (MTRRs) may be used to control
1708	  processor access to memory ranges. This is most useful if you have
1709	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1710	  allows bus write transfers to be combined into a larger transfer
1711	  before bursting over the PCI/AGP bus. This can increase performance
1712	  of image write operations 2.5 times or more. Saying Y here creates a
1713	  /proc/mtrr file which may be used to manipulate your processor's
1714	  MTRRs. Typically the X server should use this.
1715
1716	  This code has a reasonably generic interface so that similar
1717	  control registers on other processors can be easily supported
1718	  as well:
1719
1720	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1721	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1722	  these, the ARRs are used to emulate the MTRRs.
1723	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1724	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1725	  write-combining. All of these processors are supported by this code
1726	  and it makes sense to say Y here if you have one of them.
1727
1728	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1729	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1730	  can lead to all sorts of problems, so it's good to say Y here.
1731
1732	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1733	  just add about 9 KB to your kernel.
1734
1735	  See <file:Documentation/x86/mtrr.txt> for more information.
1736
1737config MTRR_SANITIZER
1738	def_bool y
1739	prompt "MTRR cleanup support"
1740	depends on MTRR
1741	---help---
1742	  Convert MTRR layout from continuous to discrete, so X drivers can
1743	  add writeback entries.
1744
1745	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1746	  The largest mtrr entry size for a continuous block can be set with
1747	  mtrr_chunk_size.
1748
1749	  If unsure, say Y.
1750
1751config MTRR_SANITIZER_ENABLE_DEFAULT
1752	int "MTRR cleanup enable value (0-1)"
1753	range 0 1
1754	default "0"
1755	depends on MTRR_SANITIZER
1756	---help---
1757	  Enable mtrr cleanup default value
1758
1759config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1760	int "MTRR cleanup spare reg num (0-7)"
1761	range 0 7
1762	default "1"
1763	depends on MTRR_SANITIZER
1764	---help---
1765	  mtrr cleanup spare entries default, it can be changed via
1766	  mtrr_spare_reg_nr=N on the kernel command line.
1767
1768config X86_PAT
1769	def_bool y
1770	prompt "x86 PAT support" if EXPERT
1771	depends on MTRR
1772	---help---
1773	  Use PAT attributes to setup page level cache control.
1774
1775	  PATs are the modern equivalents of MTRRs and are much more
1776	  flexible than MTRRs.
1777
1778	  Say N here if you see bootup problems (boot crash, boot hang,
1779	  spontaneous reboots) or a non-working video driver.
1780
1781	  If unsure, say Y.
1782
1783config ARCH_USES_PG_UNCACHED
1784	def_bool y
1785	depends on X86_PAT
1786
1787config ARCH_RANDOM
1788	def_bool y
1789	prompt "x86 architectural random number generator" if EXPERT
1790	---help---
1791	  Enable the x86 architectural RDRAND instruction
1792	  (Intel Bull Mountain technology) to generate random numbers.
1793	  If supported, this is a high bandwidth, cryptographically
1794	  secure hardware random number generator.
1795
1796config X86_SMAP
1797	def_bool y
1798	prompt "Supervisor Mode Access Prevention" if EXPERT
1799	---help---
1800	  Supervisor Mode Access Prevention (SMAP) is a security
1801	  feature in newer Intel processors.  There is a small
1802	  performance cost if this enabled and turned on; there is
1803	  also a small increase in the kernel size if this is enabled.
1804
1805	  If unsure, say Y.
1806
1807config X86_INTEL_UMIP
1808	def_bool y
1809	depends on CPU_SUP_INTEL
1810	prompt "Intel User Mode Instruction Prevention" if EXPERT
1811	---help---
1812	  The User Mode Instruction Prevention (UMIP) is a security
1813	  feature in newer Intel processors. If enabled, a general
1814	  protection fault is issued if the SGDT, SLDT, SIDT, SMSW
1815	  or STR instructions are executed in user mode. These instructions
1816	  unnecessarily expose information about the hardware state.
1817
1818	  The vast majority of applications do not use these instructions.
1819	  For the very few that do, software emulation is provided in
1820	  specific cases in protected and virtual-8086 modes. Emulated
1821	  results are dummy.
1822
1823config X86_INTEL_MPX
1824	prompt "Intel MPX (Memory Protection Extensions)"
1825	def_bool n
1826	# Note: only available in 64-bit mode due to VMA flags shortage
1827	depends on CPU_SUP_INTEL && X86_64
1828	select ARCH_USES_HIGH_VMA_FLAGS
1829	---help---
1830	  MPX provides hardware features that can be used in
1831	  conjunction with compiler-instrumented code to check
1832	  memory references.  It is designed to detect buffer
1833	  overflow or underflow bugs.
1834
1835	  This option enables running applications which are
1836	  instrumented or otherwise use MPX.  It does not use MPX
1837	  itself inside the kernel or to protect the kernel
1838	  against bad memory references.
1839
1840	  Enabling this option will make the kernel larger:
1841	  ~8k of kernel text and 36 bytes of data on a 64-bit
1842	  defconfig.  It adds a long to the 'mm_struct' which
1843	  will increase the kernel memory overhead of each
1844	  process and adds some branches to paths used during
1845	  exec() and munmap().
1846
1847	  For details, see Documentation/x86/intel_mpx.txt
1848
1849	  If unsure, say N.
1850
1851config X86_INTEL_MEMORY_PROTECTION_KEYS
1852	prompt "Intel Memory Protection Keys"
1853	def_bool y
1854	# Note: only available in 64-bit mode
1855	depends on CPU_SUP_INTEL && X86_64
1856	select ARCH_USES_HIGH_VMA_FLAGS
1857	select ARCH_HAS_PKEYS
1858	---help---
1859	  Memory Protection Keys provides a mechanism for enforcing
1860	  page-based protections, but without requiring modification of the
1861	  page tables when an application changes protection domains.
1862
1863	  For details, see Documentation/x86/protection-keys.txt
1864
1865	  If unsure, say y.
1866
1867config EFI
1868	bool "EFI runtime service support"
1869	depends on ACPI
1870	select UCS2_STRING
1871	select EFI_RUNTIME_WRAPPERS
1872	---help---
1873	  This enables the kernel to use EFI runtime services that are
1874	  available (such as the EFI variable services).
1875
1876	  This option is only useful on systems that have EFI firmware.
1877	  In addition, you should use the latest ELILO loader available
1878	  at <http://elilo.sourceforge.net> in order to take advantage
1879	  of EFI runtime services. However, even with this option, the
1880	  resultant kernel should continue to boot on existing non-EFI
1881	  platforms.
1882
1883config EFI_STUB
1884       bool "EFI stub support"
1885       depends on EFI && !X86_USE_3DNOW
1886       select RELOCATABLE
1887       ---help---
1888          This kernel feature allows a bzImage to be loaded directly
1889	  by EFI firmware without the use of a bootloader.
1890
1891	  See Documentation/efi-stub.txt for more information.
1892
1893config EFI_MIXED
1894	bool "EFI mixed-mode support"
1895	depends on EFI_STUB && X86_64
1896	---help---
1897	   Enabling this feature allows a 64-bit kernel to be booted
1898	   on a 32-bit firmware, provided that your CPU supports 64-bit
1899	   mode.
1900
1901	   Note that it is not possible to boot a mixed-mode enabled
1902	   kernel via the EFI boot stub - a bootloader that supports
1903	   the EFI handover protocol must be used.
1904
1905	   If unsure, say N.
1906
1907config SECCOMP
1908	def_bool y
1909	prompt "Enable seccomp to safely compute untrusted bytecode"
1910	---help---
1911	  This kernel feature is useful for number crunching applications
1912	  that may need to compute untrusted bytecode during their
1913	  execution. By using pipes or other transports made available to
1914	  the process as file descriptors supporting the read/write
1915	  syscalls, it's possible to isolate those applications in
1916	  their own address space using seccomp. Once seccomp is
1917	  enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1918	  and the task is only allowed to execute a few safe syscalls
1919	  defined by each seccomp mode.
1920
1921	  If unsure, say Y. Only embedded should say N here.
1922
1923source kernel/Kconfig.hz
1924
1925config KEXEC
1926	bool "kexec system call"
1927	select KEXEC_CORE
1928	---help---
1929	  kexec is a system call that implements the ability to shutdown your
1930	  current kernel, and to start another kernel.  It is like a reboot
1931	  but it is independent of the system firmware.   And like a reboot
1932	  you can start any kernel with it, not just Linux.
1933
1934	  The name comes from the similarity to the exec system call.
1935
1936	  It is an ongoing process to be certain the hardware in a machine
1937	  is properly shutdown, so do not be surprised if this code does not
1938	  initially work for you.  As of this writing the exact hardware
1939	  interface is strongly in flux, so no good recommendation can be
1940	  made.
1941
1942config KEXEC_FILE
1943	bool "kexec file based system call"
1944	select KEXEC_CORE
1945	select BUILD_BIN2C
1946	depends on X86_64
1947	depends on CRYPTO=y
1948	depends on CRYPTO_SHA256=y
1949	---help---
1950	  This is new version of kexec system call. This system call is
1951	  file based and takes file descriptors as system call argument
1952	  for kernel and initramfs as opposed to list of segments as
1953	  accepted by previous system call.
1954
1955config KEXEC_VERIFY_SIG
1956	bool "Verify kernel signature during kexec_file_load() syscall"
1957	depends on KEXEC_FILE
1958	---help---
1959	  This option makes kernel signature verification mandatory for
1960	  the kexec_file_load() syscall.
1961
1962	  In addition to that option, you need to enable signature
1963	  verification for the corresponding kernel image type being
1964	  loaded in order for this to work.
1965
1966config KEXEC_BZIMAGE_VERIFY_SIG
1967	bool "Enable bzImage signature verification support"
1968	depends on KEXEC_VERIFY_SIG
1969	depends on SIGNED_PE_FILE_VERIFICATION
1970	select SYSTEM_TRUSTED_KEYRING
1971	---help---
1972	  Enable bzImage signature verification support.
1973
1974config CRASH_DUMP
1975	bool "kernel crash dumps"
1976	depends on X86_64 || (X86_32 && HIGHMEM)
1977	---help---
1978	  Generate crash dump after being started by kexec.
1979	  This should be normally only set in special crash dump kernels
1980	  which are loaded in the main kernel with kexec-tools into
1981	  a specially reserved region and then later executed after
1982	  a crash by kdump/kexec. The crash dump kernel must be compiled
1983	  to a memory address not used by the main kernel or BIOS using
1984	  PHYSICAL_START, or it must be built as a relocatable image
1985	  (CONFIG_RELOCATABLE=y).
1986	  For more details see Documentation/kdump/kdump.txt
1987
1988config KEXEC_JUMP
1989	bool "kexec jump"
1990	depends on KEXEC && HIBERNATION
1991	---help---
1992	  Jump between original kernel and kexeced kernel and invoke
1993	  code in physical address mode via KEXEC
1994
1995config PHYSICAL_START
1996	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1997	default "0x1000000"
1998	---help---
1999	  This gives the physical address where the kernel is loaded.
2000
2001	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2002	  bzImage will decompress itself to above physical address and
2003	  run from there. Otherwise, bzImage will run from the address where
2004	  it has been loaded by the boot loader and will ignore above physical
2005	  address.
2006
2007	  In normal kdump cases one does not have to set/change this option
2008	  as now bzImage can be compiled as a completely relocatable image
2009	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2010	  address. This option is mainly useful for the folks who don't want
2011	  to use a bzImage for capturing the crash dump and want to use a
2012	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2013	  to be specifically compiled to run from a specific memory area
2014	  (normally a reserved region) and this option comes handy.
2015
2016	  So if you are using bzImage for capturing the crash dump,
2017	  leave the value here unchanged to 0x1000000 and set
2018	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2019	  for capturing the crash dump change this value to start of
2020	  the reserved region.  In other words, it can be set based on
2021	  the "X" value as specified in the "crashkernel=YM@XM"
2022	  command line boot parameter passed to the panic-ed
2023	  kernel. Please take a look at Documentation/kdump/kdump.txt
2024	  for more details about crash dumps.
2025
2026	  Usage of bzImage for capturing the crash dump is recommended as
2027	  one does not have to build two kernels. Same kernel can be used
2028	  as production kernel and capture kernel. Above option should have
2029	  gone away after relocatable bzImage support is introduced. But it
2030	  is present because there are users out there who continue to use
2031	  vmlinux for dump capture. This option should go away down the
2032	  line.
2033
2034	  Don't change this unless you know what you are doing.
2035
2036config RELOCATABLE
2037	bool "Build a relocatable kernel"
2038	default y
2039	---help---
2040	  This builds a kernel image that retains relocation information
2041	  so it can be loaded someplace besides the default 1MB.
2042	  The relocations tend to make the kernel binary about 10% larger,
2043	  but are discarded at runtime.
2044
2045	  One use is for the kexec on panic case where the recovery kernel
2046	  must live at a different physical address than the primary
2047	  kernel.
2048
2049	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2050	  it has been loaded at and the compile time physical address
2051	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2052
2053config RANDOMIZE_BASE
2054	bool "Randomize the address of the kernel image (KASLR)"
2055	depends on RELOCATABLE
2056	default y
2057	---help---
2058	  In support of Kernel Address Space Layout Randomization (KASLR),
2059	  this randomizes the physical address at which the kernel image
2060	  is decompressed and the virtual address where the kernel
2061	  image is mapped, as a security feature that deters exploit
2062	  attempts relying on knowledge of the location of kernel
2063	  code internals.
2064
2065	  On 64-bit, the kernel physical and virtual addresses are
2066	  randomized separately. The physical address will be anywhere
2067	  between 16MB and the top of physical memory (up to 64TB). The
2068	  virtual address will be randomized from 16MB up to 1GB (9 bits
2069	  of entropy). Note that this also reduces the memory space
2070	  available to kernel modules from 1.5GB to 1GB.
2071
2072	  On 32-bit, the kernel physical and virtual addresses are
2073	  randomized together. They will be randomized from 16MB up to
2074	  512MB (8 bits of entropy).
2075
2076	  Entropy is generated using the RDRAND instruction if it is
2077	  supported. If RDTSC is supported, its value is mixed into
2078	  the entropy pool as well. If neither RDRAND nor RDTSC are
2079	  supported, then entropy is read from the i8254 timer. The
2080	  usable entropy is limited by the kernel being built using
2081	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2082	  minimum of 2MB. As a result, only 10 bits of entropy are
2083	  theoretically possible, but the implementations are further
2084	  limited due to memory layouts.
2085
2086	  If unsure, say Y.
2087
2088# Relocation on x86 needs some additional build support
2089config X86_NEED_RELOCS
2090	def_bool y
2091	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2092
2093config PHYSICAL_ALIGN
2094	hex "Alignment value to which kernel should be aligned"
2095	default "0x200000"
2096	range 0x2000 0x1000000 if X86_32
2097	range 0x200000 0x1000000 if X86_64
2098	---help---
2099	  This value puts the alignment restrictions on physical address
2100	  where kernel is loaded and run from. Kernel is compiled for an
2101	  address which meets above alignment restriction.
2102
2103	  If bootloader loads the kernel at a non-aligned address and
2104	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2105	  address aligned to above value and run from there.
2106
2107	  If bootloader loads the kernel at a non-aligned address and
2108	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2109	  load address and decompress itself to the address it has been
2110	  compiled for and run from there. The address for which kernel is
2111	  compiled already meets above alignment restrictions. Hence the
2112	  end result is that kernel runs from a physical address meeting
2113	  above alignment restrictions.
2114
2115	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2116	  this value must be a multiple of 0x200000.
2117
2118	  Don't change this unless you know what you are doing.
2119
2120config RANDOMIZE_MEMORY
2121	bool "Randomize the kernel memory sections"
2122	depends on X86_64
2123	depends on RANDOMIZE_BASE
2124	default RANDOMIZE_BASE
2125	---help---
2126	   Randomizes the base virtual address of kernel memory sections
2127	   (physical memory mapping, vmalloc & vmemmap). This security feature
2128	   makes exploits relying on predictable memory locations less reliable.
2129
2130	   The order of allocations remains unchanged. Entropy is generated in
2131	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2132	   configuration have in average 30,000 different possible virtual
2133	   addresses for each memory section.
2134
2135	   If unsure, say Y.
2136
2137config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2138	hex "Physical memory mapping padding" if EXPERT
2139	depends on RANDOMIZE_MEMORY
2140	default "0xa" if MEMORY_HOTPLUG
2141	default "0x0"
2142	range 0x1 0x40 if MEMORY_HOTPLUG
2143	range 0x0 0x40
2144	---help---
2145	   Define the padding in terabytes added to the existing physical
2146	   memory size during kernel memory randomization. It is useful
2147	   for memory hotplug support but reduces the entropy available for
2148	   address randomization.
2149
2150	   If unsure, leave at the default value.
2151
2152config HOTPLUG_CPU
2153	bool "Support for hot-pluggable CPUs"
2154	depends on SMP
2155	---help---
2156	  Say Y here to allow turning CPUs off and on. CPUs can be
2157	  controlled through /sys/devices/system/cpu.
2158	  ( Note: power management support will enable this option
2159	    automatically on SMP systems. )
2160	  Say N if you want to disable CPU hotplug.
2161
2162config BOOTPARAM_HOTPLUG_CPU0
2163	bool "Set default setting of cpu0_hotpluggable"
2164	default n
2165	depends on HOTPLUG_CPU
2166	---help---
2167	  Set whether default state of cpu0_hotpluggable is on or off.
2168
2169	  Say Y here to enable CPU0 hotplug by default. If this switch
2170	  is turned on, there is no need to give cpu0_hotplug kernel
2171	  parameter and the CPU0 hotplug feature is enabled by default.
2172
2173	  Please note: there are two known CPU0 dependencies if you want
2174	  to enable the CPU0 hotplug feature either by this switch or by
2175	  cpu0_hotplug kernel parameter.
2176
2177	  First, resume from hibernate or suspend always starts from CPU0.
2178	  So hibernate and suspend are prevented if CPU0 is offline.
2179
2180	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2181	  offline if any interrupt can not migrate out of CPU0. There may
2182	  be other CPU0 dependencies.
2183
2184	  Please make sure the dependencies are under your control before
2185	  you enable this feature.
2186
2187	  Say N if you don't want to enable CPU0 hotplug feature by default.
2188	  You still can enable the CPU0 hotplug feature at boot by kernel
2189	  parameter cpu0_hotplug.
2190
2191config DEBUG_HOTPLUG_CPU0
2192	def_bool n
2193	prompt "Debug CPU0 hotplug"
2194	depends on HOTPLUG_CPU
2195	---help---
2196	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2197	  soon as possible and boots up userspace with CPU0 offlined. User
2198	  can online CPU0 back after boot time.
2199
2200	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2201	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2202	  compilation or giving cpu0_hotplug kernel parameter at boot.
2203
2204	  If unsure, say N.
2205
2206config COMPAT_VDSO
2207	def_bool n
2208	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2209	depends on COMPAT_32
2210	---help---
2211	  Certain buggy versions of glibc will crash if they are
2212	  presented with a 32-bit vDSO that is not mapped at the address
2213	  indicated in its segment table.
2214
2215	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2216	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2217	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2218	  the only released version with the bug, but OpenSUSE 9
2219	  contains a buggy "glibc 2.3.2".
2220
2221	  The symptom of the bug is that everything crashes on startup, saying:
2222	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2223
2224	  Saying Y here changes the default value of the vdso32 boot
2225	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2226	  This works around the glibc bug but hurts performance.
2227
2228	  If unsure, say N: if you are compiling your own kernel, you
2229	  are unlikely to be using a buggy version of glibc.
2230
2231choice
2232	prompt "vsyscall table for legacy applications"
2233	depends on X86_64
2234	default LEGACY_VSYSCALL_EMULATE
2235	help
2236	  Legacy user code that does not know how to find the vDSO expects
2237	  to be able to issue three syscalls by calling fixed addresses in
2238	  kernel space. Since this location is not randomized with ASLR,
2239	  it can be used to assist security vulnerability exploitation.
2240
2241	  This setting can be changed at boot time via the kernel command
2242	  line parameter vsyscall=[native|emulate|none].
2243
2244	  On a system with recent enough glibc (2.14 or newer) and no
2245	  static binaries, you can say None without a performance penalty
2246	  to improve security.
2247
2248	  If unsure, select "Emulate".
2249
2250	config LEGACY_VSYSCALL_NATIVE
2251		bool "Native"
2252		help
2253		  Actual executable code is located in the fixed vsyscall
2254		  address mapping, implementing time() efficiently. Since
2255		  this makes the mapping executable, it can be used during
2256		  security vulnerability exploitation (traditionally as
2257		  ROP gadgets). This configuration is not recommended.
2258
2259	config LEGACY_VSYSCALL_EMULATE
2260		bool "Emulate"
2261		help
2262		  The kernel traps and emulates calls into the fixed
2263		  vsyscall address mapping. This makes the mapping
2264		  non-executable, but it still contains known contents,
2265		  which could be used in certain rare security vulnerability
2266		  exploits. This configuration is recommended when userspace
2267		  still uses the vsyscall area.
2268
2269	config LEGACY_VSYSCALL_NONE
2270		bool "None"
2271		help
2272		  There will be no vsyscall mapping at all. This will
2273		  eliminate any risk of ASLR bypass due to the vsyscall
2274		  fixed address mapping. Attempts to use the vsyscalls
2275		  will be reported to dmesg, so that either old or
2276		  malicious userspace programs can be identified.
2277
2278endchoice
2279
2280config CMDLINE_BOOL
2281	bool "Built-in kernel command line"
2282	---help---
2283	  Allow for specifying boot arguments to the kernel at
2284	  build time.  On some systems (e.g. embedded ones), it is
2285	  necessary or convenient to provide some or all of the
2286	  kernel boot arguments with the kernel itself (that is,
2287	  to not rely on the boot loader to provide them.)
2288
2289	  To compile command line arguments into the kernel,
2290	  set this option to 'Y', then fill in the
2291	  boot arguments in CONFIG_CMDLINE.
2292
2293	  Systems with fully functional boot loaders (i.e. non-embedded)
2294	  should leave this option set to 'N'.
2295
2296config CMDLINE
2297	string "Built-in kernel command string"
2298	depends on CMDLINE_BOOL
2299	default ""
2300	---help---
2301	  Enter arguments here that should be compiled into the kernel
2302	  image and used at boot time.  If the boot loader provides a
2303	  command line at boot time, it is appended to this string to
2304	  form the full kernel command line, when the system boots.
2305
2306	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2307	  change this behavior.
2308
2309	  In most cases, the command line (whether built-in or provided
2310	  by the boot loader) should specify the device for the root
2311	  file system.
2312
2313config CMDLINE_OVERRIDE
2314	bool "Built-in command line overrides boot loader arguments"
2315	depends on CMDLINE_BOOL
2316	---help---
2317	  Set this option to 'Y' to have the kernel ignore the boot loader
2318	  command line, and use ONLY the built-in command line.
2319
2320	  This is used to work around broken boot loaders.  This should
2321	  be set to 'N' under normal conditions.
2322
2323config MODIFY_LDT_SYSCALL
2324	bool "Enable the LDT (local descriptor table)" if EXPERT
2325	default y
2326	---help---
2327	  Linux can allow user programs to install a per-process x86
2328	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2329	  call.  This is required to run 16-bit or segmented code such as
2330	  DOSEMU or some Wine programs.  It is also used by some very old
2331	  threading libraries.
2332
2333	  Enabling this feature adds a small amount of overhead to
2334	  context switches and increases the low-level kernel attack
2335	  surface.  Disabling it removes the modify_ldt(2) system call.
2336
2337	  Saying 'N' here may make sense for embedded or server kernels.
2338
2339source "kernel/livepatch/Kconfig"
2340
2341endmenu
2342
2343config ARCH_HAS_ADD_PAGES
2344	def_bool y
2345	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2346
2347config ARCH_ENABLE_MEMORY_HOTPLUG
2348	def_bool y
2349	depends on X86_64 || (X86_32 && HIGHMEM)
2350
2351config ARCH_ENABLE_MEMORY_HOTREMOVE
2352	def_bool y
2353	depends on MEMORY_HOTPLUG
2354
2355config USE_PERCPU_NUMA_NODE_ID
2356	def_bool y
2357	depends on NUMA
2358
2359config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2360	def_bool y
2361	depends on X86_64 || X86_PAE
2362
2363config ARCH_ENABLE_HUGEPAGE_MIGRATION
2364	def_bool y
2365	depends on X86_64 && HUGETLB_PAGE && MIGRATION
2366
2367config ARCH_ENABLE_THP_MIGRATION
2368	def_bool y
2369	depends on X86_64 && TRANSPARENT_HUGEPAGE
2370
2371menu "Power management and ACPI options"
2372
2373config ARCH_HIBERNATION_HEADER
2374	def_bool y
2375	depends on X86_64 && HIBERNATION
2376
2377source "kernel/power/Kconfig"
2378
2379source "drivers/acpi/Kconfig"
2380
2381source "drivers/sfi/Kconfig"
2382
2383config X86_APM_BOOT
2384	def_bool y
2385	depends on APM
2386
2387menuconfig APM
2388	tristate "APM (Advanced Power Management) BIOS support"
2389	depends on X86_32 && PM_SLEEP
2390	---help---
2391	  APM is a BIOS specification for saving power using several different
2392	  techniques. This is mostly useful for battery powered laptops with
2393	  APM compliant BIOSes. If you say Y here, the system time will be
2394	  reset after a RESUME operation, the /proc/apm device will provide
2395	  battery status information, and user-space programs will receive
2396	  notification of APM "events" (e.g. battery status change).
2397
2398	  If you select "Y" here, you can disable actual use of the APM
2399	  BIOS by passing the "apm=off" option to the kernel at boot time.
2400
2401	  Note that the APM support is almost completely disabled for
2402	  machines with more than one CPU.
2403
2404	  In order to use APM, you will need supporting software. For location
2405	  and more information, read <file:Documentation/power/apm-acpi.txt>
2406	  and the Battery Powered Linux mini-HOWTO, available from
2407	  <http://www.tldp.org/docs.html#howto>.
2408
2409	  This driver does not spin down disk drives (see the hdparm(8)
2410	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2411	  VESA-compliant "green" monitors.
2412
2413	  This driver does not support the TI 4000M TravelMate and the ACER
2414	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2415	  desktop machines also don't have compliant BIOSes, and this driver
2416	  may cause those machines to panic during the boot phase.
2417
2418	  Generally, if you don't have a battery in your machine, there isn't
2419	  much point in using this driver and you should say N. If you get
2420	  random kernel OOPSes or reboots that don't seem to be related to
2421	  anything, try disabling/enabling this option (or disabling/enabling
2422	  APM in your BIOS).
2423
2424	  Some other things you should try when experiencing seemingly random,
2425	  "weird" problems:
2426
2427	  1) make sure that you have enough swap space and that it is
2428	  enabled.
2429	  2) pass the "no-hlt" option to the kernel
2430	  3) switch on floating point emulation in the kernel and pass
2431	  the "no387" option to the kernel
2432	  4) pass the "floppy=nodma" option to the kernel
2433	  5) pass the "mem=4M" option to the kernel (thereby disabling
2434	  all but the first 4 MB of RAM)
2435	  6) make sure that the CPU is not over clocked.
2436	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2437	  8) disable the cache from your BIOS settings
2438	  9) install a fan for the video card or exchange video RAM
2439	  10) install a better fan for the CPU
2440	  11) exchange RAM chips
2441	  12) exchange the motherboard.
2442
2443	  To compile this driver as a module, choose M here: the
2444	  module will be called apm.
2445
2446if APM
2447
2448config APM_IGNORE_USER_SUSPEND
2449	bool "Ignore USER SUSPEND"
2450	---help---
2451	  This option will ignore USER SUSPEND requests. On machines with a
2452	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2453	  series notebooks, it is necessary to say Y because of a BIOS bug.
2454
2455config APM_DO_ENABLE
2456	bool "Enable PM at boot time"
2457	---help---
2458	  Enable APM features at boot time. From page 36 of the APM BIOS
2459	  specification: "When disabled, the APM BIOS does not automatically
2460	  power manage devices, enter the Standby State, enter the Suspend
2461	  State, or take power saving steps in response to CPU Idle calls."
2462	  This driver will make CPU Idle calls when Linux is idle (unless this
2463	  feature is turned off -- see "Do CPU IDLE calls", below). This
2464	  should always save battery power, but more complicated APM features
2465	  will be dependent on your BIOS implementation. You may need to turn
2466	  this option off if your computer hangs at boot time when using APM
2467	  support, or if it beeps continuously instead of suspending. Turn
2468	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2469	  T400CDT. This is off by default since most machines do fine without
2470	  this feature.
2471
2472config APM_CPU_IDLE
2473	depends on CPU_IDLE
2474	bool "Make CPU Idle calls when idle"
2475	---help---
2476	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2477	  On some machines, this can activate improved power savings, such as
2478	  a slowed CPU clock rate, when the machine is idle. These idle calls
2479	  are made after the idle loop has run for some length of time (e.g.,
2480	  333 mS). On some machines, this will cause a hang at boot time or
2481	  whenever the CPU becomes idle. (On machines with more than one CPU,
2482	  this option does nothing.)
2483
2484config APM_DISPLAY_BLANK
2485	bool "Enable console blanking using APM"
2486	---help---
2487	  Enable console blanking using the APM. Some laptops can use this to
2488	  turn off the LCD backlight when the screen blanker of the Linux
2489	  virtual console blanks the screen. Note that this is only used by
2490	  the virtual console screen blanker, and won't turn off the backlight
2491	  when using the X Window system. This also doesn't have anything to
2492	  do with your VESA-compliant power-saving monitor. Further, this
2493	  option doesn't work for all laptops -- it might not turn off your
2494	  backlight at all, or it might print a lot of errors to the console,
2495	  especially if you are using gpm.
2496
2497config APM_ALLOW_INTS
2498	bool "Allow interrupts during APM BIOS calls"
2499	---help---
2500	  Normally we disable external interrupts while we are making calls to
2501	  the APM BIOS as a measure to lessen the effects of a badly behaving
2502	  BIOS implementation.  The BIOS should reenable interrupts if it
2503	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2504	  many of the newer IBM Thinkpads.  If you experience hangs when you
2505	  suspend, try setting this to Y.  Otherwise, say N.
2506
2507endif # APM
2508
2509source "drivers/cpufreq/Kconfig"
2510
2511source "drivers/cpuidle/Kconfig"
2512
2513source "drivers/idle/Kconfig"
2514
2515endmenu
2516
2517
2518menu "Bus options (PCI etc.)"
2519
2520config PCI
2521	bool "PCI support"
2522	default y
2523	---help---
2524	  Find out whether you have a PCI motherboard. PCI is the name of a
2525	  bus system, i.e. the way the CPU talks to the other stuff inside
2526	  your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
2527	  VESA. If you have PCI, say Y, otherwise N.
2528
2529choice
2530	prompt "PCI access mode"
2531	depends on X86_32 && PCI
2532	default PCI_GOANY
2533	---help---
2534	  On PCI systems, the BIOS can be used to detect the PCI devices and
2535	  determine their configuration. However, some old PCI motherboards
2536	  have BIOS bugs and may crash if this is done. Also, some embedded
2537	  PCI-based systems don't have any BIOS at all. Linux can also try to
2538	  detect the PCI hardware directly without using the BIOS.
2539
2540	  With this option, you can specify how Linux should detect the
2541	  PCI devices. If you choose "BIOS", the BIOS will be used,
2542	  if you choose "Direct", the BIOS won't be used, and if you
2543	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2544	  If you choose "Any", the kernel will try MMCONFIG, then the
2545	  direct access method and falls back to the BIOS if that doesn't
2546	  work. If unsure, go with the default, which is "Any".
2547
2548config PCI_GOBIOS
2549	bool "BIOS"
2550
2551config PCI_GOMMCONFIG
2552	bool "MMConfig"
2553
2554config PCI_GODIRECT
2555	bool "Direct"
2556
2557config PCI_GOOLPC
2558	bool "OLPC XO-1"
2559	depends on OLPC
2560
2561config PCI_GOANY
2562	bool "Any"
2563
2564endchoice
2565
2566config PCI_BIOS
2567	def_bool y
2568	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2569
2570# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2571config PCI_DIRECT
2572	def_bool y
2573	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2574
2575config PCI_MMCONFIG
2576	def_bool y
2577	depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
2578
2579config PCI_OLPC
2580	def_bool y
2581	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2582
2583config PCI_XEN
2584	def_bool y
2585	depends on PCI && XEN
2586	select SWIOTLB_XEN
2587
2588config PCI_DOMAINS
2589	def_bool y
2590	depends on PCI
2591
2592config PCI_MMCONFIG
2593	bool "Support mmconfig PCI config space access"
2594	depends on X86_64 && PCI && ACPI
2595
2596config PCI_CNB20LE_QUIRK
2597	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2598	depends on PCI
2599	help
2600	  Read the PCI windows out of the CNB20LE host bridge. This allows
2601	  PCI hotplug to work on systems with the CNB20LE chipset which do
2602	  not have ACPI.
2603
2604	  There's no public spec for this chipset, and this functionality
2605	  is known to be incomplete.
2606
2607	  You should say N unless you know you need this.
2608
2609source "drivers/pci/Kconfig"
2610
2611config ISA_BUS
2612	bool "ISA-style bus support on modern systems" if EXPERT
2613	select ISA_BUS_API
2614	help
2615	  Enables ISA-style drivers on modern systems. This is necessary to
2616	  support PC/104 devices on X86_64 platforms.
2617
2618	  If unsure, say N.
2619
2620# x86_64 have no ISA slots, but can have ISA-style DMA.
2621config ISA_DMA_API
2622	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2623	default y
2624	help
2625	  Enables ISA-style DMA support for devices requiring such controllers.
2626	  If unsure, say Y.
2627
2628if X86_32
2629
2630config ISA
2631	bool "ISA support"
2632	---help---
2633	  Find out whether you have ISA slots on your motherboard.  ISA is the
2634	  name of a bus system, i.e. the way the CPU talks to the other stuff
2635	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2636	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2637	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2638
2639config EISA
2640	bool "EISA support"
2641	depends on ISA
2642	---help---
2643	  The Extended Industry Standard Architecture (EISA) bus was
2644	  developed as an open alternative to the IBM MicroChannel bus.
2645
2646	  The EISA bus provided some of the features of the IBM MicroChannel
2647	  bus while maintaining backward compatibility with cards made for
2648	  the older ISA bus.  The EISA bus saw limited use between 1988 and
2649	  1995 when it was made obsolete by the PCI bus.
2650
2651	  Say Y here if you are building a kernel for an EISA-based machine.
2652
2653	  Otherwise, say N.
2654
2655source "drivers/eisa/Kconfig"
2656
2657config SCx200
2658	tristate "NatSemi SCx200 support"
2659	---help---
2660	  This provides basic support for National Semiconductor's
2661	  (now AMD's) Geode processors.  The driver probes for the
2662	  PCI-IDs of several on-chip devices, so its a good dependency
2663	  for other scx200_* drivers.
2664
2665	  If compiled as a module, the driver is named scx200.
2666
2667config SCx200HR_TIMER
2668	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2669	depends on SCx200
2670	default y
2671	---help---
2672	  This driver provides a clocksource built upon the on-chip
2673	  27MHz high-resolution timer.  Its also a workaround for
2674	  NSC Geode SC-1100's buggy TSC, which loses time when the
2675	  processor goes idle (as is done by the scheduler).  The
2676	  other workaround is idle=poll boot option.
2677
2678config OLPC
2679	bool "One Laptop Per Child support"
2680	depends on !X86_PAE
2681	select GPIOLIB
2682	select OF
2683	select OF_PROMTREE
2684	select IRQ_DOMAIN
2685	---help---
2686	  Add support for detecting the unique features of the OLPC
2687	  XO hardware.
2688
2689config OLPC_XO1_PM
2690	bool "OLPC XO-1 Power Management"
2691	depends on OLPC && MFD_CS5535 && PM_SLEEP
2692	select MFD_CORE
2693	---help---
2694	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2695
2696config OLPC_XO1_RTC
2697	bool "OLPC XO-1 Real Time Clock"
2698	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2699	---help---
2700	  Add support for the XO-1 real time clock, which can be used as a
2701	  programmable wakeup source.
2702
2703config OLPC_XO1_SCI
2704	bool "OLPC XO-1 SCI extras"
2705	depends on OLPC && OLPC_XO1_PM
2706	depends on INPUT=y
2707	select POWER_SUPPLY
2708	select GPIO_CS5535
2709	select MFD_CORE
2710	---help---
2711	  Add support for SCI-based features of the OLPC XO-1 laptop:
2712	   - EC-driven system wakeups
2713	   - Power button
2714	   - Ebook switch
2715	   - Lid switch
2716	   - AC adapter status updates
2717	   - Battery status updates
2718
2719config OLPC_XO15_SCI
2720	bool "OLPC XO-1.5 SCI extras"
2721	depends on OLPC && ACPI
2722	select POWER_SUPPLY
2723	---help---
2724	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2725	   - EC-driven system wakeups
2726	   - AC adapter status updates
2727	   - Battery status updates
2728
2729config ALIX
2730	bool "PCEngines ALIX System Support (LED setup)"
2731	select GPIOLIB
2732	---help---
2733	  This option enables system support for the PCEngines ALIX.
2734	  At present this just sets up LEDs for GPIO control on
2735	  ALIX2/3/6 boards.  However, other system specific setup should
2736	  get added here.
2737
2738	  Note: You must still enable the drivers for GPIO and LED support
2739	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2740
2741	  Note: You have to set alix.force=1 for boards with Award BIOS.
2742
2743config NET5501
2744	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2745	select GPIOLIB
2746	---help---
2747	  This option enables system support for the Soekris Engineering net5501.
2748
2749config GEOS
2750	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2751	select GPIOLIB
2752	depends on DMI
2753	---help---
2754	  This option enables system support for the Traverse Technologies GEOS.
2755
2756config TS5500
2757	bool "Technologic Systems TS-5500 platform support"
2758	depends on MELAN
2759	select CHECK_SIGNATURE
2760	select NEW_LEDS
2761	select LEDS_CLASS
2762	---help---
2763	  This option enables system support for the Technologic Systems TS-5500.
2764
2765endif # X86_32
2766
2767config AMD_NB
2768	def_bool y
2769	depends on CPU_SUP_AMD && PCI
2770
2771source "drivers/pcmcia/Kconfig"
2772
2773config RAPIDIO
2774	tristate "RapidIO support"
2775	depends on PCI
2776	default n
2777	help
2778	  If enabled this option will include drivers and the core
2779	  infrastructure code to support RapidIO interconnect devices.
2780
2781source "drivers/rapidio/Kconfig"
2782
2783config X86_SYSFB
2784	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2785	help
2786	  Firmwares often provide initial graphics framebuffers so the BIOS,
2787	  bootloader or kernel can show basic video-output during boot for
2788	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2789	  Extensions and EFI-framebuffers for this, which are mostly limited
2790	  to x86.
2791	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2792	  framebuffers so the new generic system-framebuffer drivers can be
2793	  used on x86. If the framebuffer is not compatible with the generic
2794	  modes, it is adverticed as fallback platform framebuffer so legacy
2795	  drivers like efifb, vesafb and uvesafb can pick it up.
2796	  If this option is not selected, all system framebuffers are always
2797	  marked as fallback platform framebuffers as usual.
2798
2799	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2800	  not be able to pick up generic system framebuffers if this option
2801	  is selected. You are highly encouraged to enable simplefb as
2802	  replacement if you select this option. simplefb can correctly deal
2803	  with generic system framebuffers. But you should still keep vesafb
2804	  and others enabled as fallback if a system framebuffer is
2805	  incompatible with simplefb.
2806
2807	  If unsure, say Y.
2808
2809endmenu
2810
2811
2812menu "Executable file formats / Emulations"
2813
2814source "fs/Kconfig.binfmt"
2815
2816config IA32_EMULATION
2817	bool "IA32 Emulation"
2818	depends on X86_64
2819	select ARCH_WANT_OLD_COMPAT_IPC
2820	select BINFMT_ELF
2821	select COMPAT_BINFMT_ELF
2822	select COMPAT_OLD_SIGACTION
2823	---help---
2824	  Include code to run legacy 32-bit programs under a
2825	  64-bit kernel. You should likely turn this on, unless you're
2826	  100% sure that you don't have any 32-bit programs left.
2827
2828config IA32_AOUT
2829	tristate "IA32 a.out support"
2830	depends on IA32_EMULATION
2831	---help---
2832	  Support old a.out binaries in the 32bit emulation.
2833
2834config X86_X32
2835	bool "x32 ABI for 64-bit mode"
2836	depends on X86_64
2837	---help---
2838	  Include code to run binaries for the x32 native 32-bit ABI
2839	  for 64-bit processors.  An x32 process gets access to the
2840	  full 64-bit register file and wide data path while leaving
2841	  pointers at 32 bits for smaller memory footprint.
2842
2843	  You will need a recent binutils (2.22 or later) with
2844	  elf32_x86_64 support enabled to compile a kernel with this
2845	  option set.
2846
2847config COMPAT_32
2848	def_bool y
2849	depends on IA32_EMULATION || X86_32
2850	select HAVE_UID16
2851	select OLD_SIGSUSPEND3
2852
2853config COMPAT
2854	def_bool y
2855	depends on IA32_EMULATION || X86_X32
2856
2857if COMPAT
2858config COMPAT_FOR_U64_ALIGNMENT
2859	def_bool y
2860
2861config SYSVIPC_COMPAT
2862	def_bool y
2863	depends on SYSVIPC
2864endif
2865
2866endmenu
2867
2868
2869config HAVE_ATOMIC_IOMAP
2870	def_bool y
2871	depends on X86_32
2872
2873config X86_DEV_DMA_OPS
2874	bool
2875	depends on X86_64 || STA2X11
2876
2877config X86_DMA_REMAP
2878	bool
2879	depends on STA2X11
2880
2881config HAVE_GENERIC_GUP
2882	def_bool y
2883
2884source "net/Kconfig"
2885
2886source "drivers/Kconfig"
2887
2888source "drivers/firmware/Kconfig"
2889
2890source "fs/Kconfig"
2891
2892source "arch/x86/Kconfig.debug"
2893
2894source "security/Kconfig"
2895
2896source "crypto/Kconfig"
2897
2898source "arch/x86/kvm/Kconfig"
2899
2900source "lib/Kconfig"
2901