xref: /openbmc/linux/arch/x86/Kconfig (revision 2c64e9cb)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	---help---
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select HAVE_DEBUG_STACKOVERFLOW
18	select MODULES_USE_ELF_REL
19	select OLD_SIGACTION
20
21config X86_64
22	def_bool y
23	depends on 64BIT
24	# Options that are inherently 64-bit kernel only:
25	select ARCH_HAS_GIGANTIC_PAGE
26	select ARCH_SUPPORTS_INT128
27	select ARCH_USE_CMPXCHG_LOCKREF
28	select HAVE_ARCH_SOFT_DIRTY
29	select MODULES_USE_ELF_RELA
30	select NEED_DMA_MAP_STATE
31	select SWIOTLB
32	select ARCH_HAS_SYSCALL_WRAPPER
33
34#
35# Arch settings
36#
37# ( Note that options that are marked 'if X86_64' could in principle be
38#   ported to 32-bit as well. )
39#
40config X86
41	def_bool y
42	#
43	# Note: keep this list sorted alphabetically
44	#
45	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
46	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
47	select ARCH_32BIT_OFF_T			if X86_32
48	select ARCH_CLOCKSOURCE_DATA
49	select ARCH_CLOCKSOURCE_INIT
50	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
51	select ARCH_HAS_DEBUG_VIRTUAL
52	select ARCH_HAS_DEVMEM_IS_ALLOWED
53	select ARCH_HAS_ELF_RANDOMIZE
54	select ARCH_HAS_FAST_MULTIPLIER
55	select ARCH_HAS_FILTER_PGPROT
56	select ARCH_HAS_FORTIFY_SOURCE
57	select ARCH_HAS_GCOV_PROFILE_ALL
58	select ARCH_HAS_KCOV			if X86_64
59	select ARCH_HAS_MEMBARRIER_SYNC_CORE
60	select ARCH_HAS_PMEM_API		if X86_64
61	select ARCH_HAS_PTE_SPECIAL
62	select ARCH_HAS_REFCOUNT
63	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
64	select ARCH_HAS_UACCESS_MCSAFE		if X86_64 && X86_MCE
65	select ARCH_HAS_SET_MEMORY
66	select ARCH_HAS_SET_DIRECT_MAP
67	select ARCH_HAS_STRICT_KERNEL_RWX
68	select ARCH_HAS_STRICT_MODULE_RWX
69	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
70	select ARCH_HAS_UBSAN_SANITIZE_ALL
71	select ARCH_HAS_ZONE_DEVICE		if X86_64
72	select ARCH_HAVE_NMI_SAFE_CMPXCHG
73	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
74	select ARCH_MIGHT_HAVE_PC_PARPORT
75	select ARCH_MIGHT_HAVE_PC_SERIO
76	select ARCH_STACKWALK
77	select ARCH_SUPPORTS_ACPI
78	select ARCH_SUPPORTS_ATOMIC_RMW
79	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
80	select ARCH_USE_BUILTIN_BSWAP
81	select ARCH_USE_QUEUED_RWLOCKS
82	select ARCH_USE_QUEUED_SPINLOCKS
83	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
84	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
85	select ARCH_WANTS_THP_SWAP		if X86_64
86	select BUILDTIME_EXTABLE_SORT
87	select CLKEVT_I8253
88	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
89	select CLOCKSOURCE_WATCHDOG
90	select DCACHE_WORD_ACCESS
91	select EDAC_ATOMIC_SCRUB
92	select EDAC_SUPPORT
93	select GENERIC_CLOCKEVENTS
94	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
95	select GENERIC_CLOCKEVENTS_MIN_ADJUST
96	select GENERIC_CMOS_UPDATE
97	select GENERIC_CPU_AUTOPROBE
98	select GENERIC_CPU_VULNERABILITIES
99	select GENERIC_EARLY_IOREMAP
100	select GENERIC_FIND_FIRST_BIT
101	select GENERIC_IOMAP
102	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
103	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
104	select GENERIC_IRQ_MIGRATION		if SMP
105	select GENERIC_IRQ_PROBE
106	select GENERIC_IRQ_RESERVATION_MODE
107	select GENERIC_IRQ_SHOW
108	select GENERIC_PENDING_IRQ		if SMP
109	select GENERIC_SMP_IDLE_THREAD
110	select GENERIC_STRNCPY_FROM_USER
111	select GENERIC_STRNLEN_USER
112	select GENERIC_TIME_VSYSCALL
113	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
114	select HAVE_ACPI_APEI			if ACPI
115	select HAVE_ACPI_APEI_NMI		if ACPI
116	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
117	select HAVE_ARCH_AUDITSYSCALL
118	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
119	select HAVE_ARCH_JUMP_LABEL
120	select HAVE_ARCH_JUMP_LABEL_RELATIVE
121	select HAVE_ARCH_KASAN			if X86_64
122	select HAVE_ARCH_KGDB
123	select HAVE_ARCH_MMAP_RND_BITS		if MMU
124	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
125	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
126	select HAVE_ARCH_PREL32_RELOCATIONS
127	select HAVE_ARCH_SECCOMP_FILTER
128	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
129	select HAVE_ARCH_STACKLEAK
130	select HAVE_ARCH_TRACEHOOK
131	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
132	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
133	select HAVE_ARCH_VMAP_STACK		if X86_64
134	select HAVE_ARCH_WITHIN_STACK_FRAMES
135	select HAVE_CMPXCHG_DOUBLE
136	select HAVE_CMPXCHG_LOCAL
137	select HAVE_CONTEXT_TRACKING		if X86_64
138	select HAVE_COPY_THREAD_TLS
139	select HAVE_C_RECORDMCOUNT
140	select HAVE_DEBUG_KMEMLEAK
141	select HAVE_DMA_CONTIGUOUS
142	select HAVE_DYNAMIC_FTRACE
143	select HAVE_DYNAMIC_FTRACE_WITH_REGS
144	select HAVE_EBPF_JIT
145	select HAVE_EFFICIENT_UNALIGNED_ACCESS
146	select HAVE_EISA
147	select HAVE_EXIT_THREAD
148	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
149	select HAVE_FTRACE_MCOUNT_RECORD
150	select HAVE_FUNCTION_GRAPH_TRACER
151	select HAVE_FUNCTION_TRACER
152	select HAVE_GCC_PLUGINS
153	select HAVE_HW_BREAKPOINT
154	select HAVE_IDE
155	select HAVE_IOREMAP_PROT
156	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
157	select HAVE_IRQ_TIME_ACCOUNTING
158	select HAVE_KERNEL_BZIP2
159	select HAVE_KERNEL_GZIP
160	select HAVE_KERNEL_LZ4
161	select HAVE_KERNEL_LZMA
162	select HAVE_KERNEL_LZO
163	select HAVE_KERNEL_XZ
164	select HAVE_KPROBES
165	select HAVE_KPROBES_ON_FTRACE
166	select HAVE_FUNCTION_ERROR_INJECTION
167	select HAVE_KRETPROBES
168	select HAVE_KVM
169	select HAVE_LIVEPATCH			if X86_64
170	select HAVE_MEMBLOCK_NODE_MAP
171	select HAVE_MIXED_BREAKPOINTS_REGS
172	select HAVE_MOD_ARCH_SPECIFIC
173	select HAVE_MOVE_PMD
174	select HAVE_NMI
175	select HAVE_OPROFILE
176	select HAVE_OPTPROBES
177	select HAVE_PCSPKR_PLATFORM
178	select HAVE_PERF_EVENTS
179	select HAVE_PERF_EVENTS_NMI
180	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
181	select HAVE_PCI
182	select HAVE_PERF_REGS
183	select HAVE_PERF_USER_STACK_DUMP
184	select HAVE_RCU_TABLE_FREE		if PARAVIRT
185	select HAVE_REGS_AND_STACK_ACCESS_API
186	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
187	select HAVE_FUNCTION_ARG_ACCESS_API
188	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
189	select HAVE_STACK_VALIDATION		if X86_64
190	select HAVE_RSEQ
191	select HAVE_SYSCALL_TRACEPOINTS
192	select HAVE_UNSTABLE_SCHED_CLOCK
193	select HAVE_USER_RETURN_NOTIFIER
194	select HOTPLUG_SMT			if SMP
195	select IRQ_FORCED_THREADING
196	select NEED_SG_DMA_LENGTH
197	select PCI_DOMAINS			if PCI
198	select PCI_LOCKLESS_CONFIG		if PCI
199	select PERF_EVENTS
200	select RTC_LIB
201	select RTC_MC146818_LIB
202	select SPARSE_IRQ
203	select SRCU
204	select SYSCTL_EXCEPTION_TRACE
205	select THREAD_INFO_IN_TASK
206	select USER_STACKTRACE_SUPPORT
207	select VIRT_TO_BUS
208	select X86_FEATURE_NAMES		if PROC_FS
209
210config INSTRUCTION_DECODER
211	def_bool y
212	depends on KPROBES || PERF_EVENTS || UPROBES
213
214config OUTPUT_FORMAT
215	string
216	default "elf32-i386" if X86_32
217	default "elf64-x86-64" if X86_64
218
219config ARCH_DEFCONFIG
220	string
221	default "arch/x86/configs/i386_defconfig" if X86_32
222	default "arch/x86/configs/x86_64_defconfig" if X86_64
223
224config LOCKDEP_SUPPORT
225	def_bool y
226
227config STACKTRACE_SUPPORT
228	def_bool y
229
230config MMU
231	def_bool y
232
233config ARCH_MMAP_RND_BITS_MIN
234	default 28 if 64BIT
235	default 8
236
237config ARCH_MMAP_RND_BITS_MAX
238	default 32 if 64BIT
239	default 16
240
241config ARCH_MMAP_RND_COMPAT_BITS_MIN
242	default 8
243
244config ARCH_MMAP_RND_COMPAT_BITS_MAX
245	default 16
246
247config SBUS
248	bool
249
250config GENERIC_ISA_DMA
251	def_bool y
252	depends on ISA_DMA_API
253
254config GENERIC_BUG
255	def_bool y
256	depends on BUG
257	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
258
259config GENERIC_BUG_RELATIVE_POINTERS
260	bool
261
262config GENERIC_HWEIGHT
263	def_bool y
264
265config ARCH_MAY_HAVE_PC_FDC
266	def_bool y
267	depends on ISA_DMA_API
268
269config GENERIC_CALIBRATE_DELAY
270	def_bool y
271
272config ARCH_HAS_CPU_RELAX
273	def_bool y
274
275config ARCH_HAS_CACHE_LINE_SIZE
276	def_bool y
277
278config ARCH_HAS_FILTER_PGPROT
279	def_bool y
280
281config HAVE_SETUP_PER_CPU_AREA
282	def_bool y
283
284config NEED_PER_CPU_EMBED_FIRST_CHUNK
285	def_bool y
286
287config NEED_PER_CPU_PAGE_FIRST_CHUNK
288	def_bool y
289
290config ARCH_HIBERNATION_POSSIBLE
291	def_bool y
292
293config ARCH_SUSPEND_POSSIBLE
294	def_bool y
295
296config ARCH_WANT_HUGE_PMD_SHARE
297	def_bool y
298
299config ARCH_WANT_GENERAL_HUGETLB
300	def_bool y
301
302config ZONE_DMA32
303	def_bool y if X86_64
304
305config AUDIT_ARCH
306	def_bool y if X86_64
307
308config ARCH_SUPPORTS_DEBUG_PAGEALLOC
309	def_bool y
310
311config KASAN_SHADOW_OFFSET
312	hex
313	depends on KASAN
314	default 0xdffffc0000000000
315
316config HAVE_INTEL_TXT
317	def_bool y
318	depends on INTEL_IOMMU && ACPI
319
320config X86_32_SMP
321	def_bool y
322	depends on X86_32 && SMP
323
324config X86_64_SMP
325	def_bool y
326	depends on X86_64 && SMP
327
328config X86_32_LAZY_GS
329	def_bool y
330	depends on X86_32 && !STACKPROTECTOR
331
332config ARCH_SUPPORTS_UPROBES
333	def_bool y
334
335config FIX_EARLYCON_MEM
336	def_bool y
337
338config DYNAMIC_PHYSICAL_MASK
339	bool
340
341config PGTABLE_LEVELS
342	int
343	default 5 if X86_5LEVEL
344	default 4 if X86_64
345	default 3 if X86_PAE
346	default 2
347
348config CC_HAS_SANE_STACKPROTECTOR
349	bool
350	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
351	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
352	help
353	   We have to make sure stack protector is unconditionally disabled if
354	   the compiler produces broken code.
355
356menu "Processor type and features"
357
358config ZONE_DMA
359	bool "DMA memory allocation support" if EXPERT
360	default y
361	help
362	  DMA memory allocation support allows devices with less than 32-bit
363	  addressing to allocate within the first 16MB of address space.
364	  Disable if no such devices will be used.
365
366	  If unsure, say Y.
367
368config SMP
369	bool "Symmetric multi-processing support"
370	---help---
371	  This enables support for systems with more than one CPU. If you have
372	  a system with only one CPU, say N. If you have a system with more
373	  than one CPU, say Y.
374
375	  If you say N here, the kernel will run on uni- and multiprocessor
376	  machines, but will use only one CPU of a multiprocessor machine. If
377	  you say Y here, the kernel will run on many, but not all,
378	  uniprocessor machines. On a uniprocessor machine, the kernel
379	  will run faster if you say N here.
380
381	  Note that if you say Y here and choose architecture "586" or
382	  "Pentium" under "Processor family", the kernel will not work on 486
383	  architectures. Similarly, multiprocessor kernels for the "PPro"
384	  architecture may not work on all Pentium based boards.
385
386	  People using multiprocessor machines who say Y here should also say
387	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
388	  Management" code will be disabled if you say Y here.
389
390	  See also <file:Documentation/x86/i386/IO-APIC.txt>,
391	  <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO available at
392	  <http://www.tldp.org/docs.html#howto>.
393
394	  If you don't know what to do here, say N.
395
396config X86_FEATURE_NAMES
397	bool "Processor feature human-readable names" if EMBEDDED
398	default y
399	---help---
400	  This option compiles in a table of x86 feature bits and corresponding
401	  names.  This is required to support /proc/cpuinfo and a few kernel
402	  messages.  You can disable this to save space, at the expense of
403	  making those few kernel messages show numeric feature bits instead.
404
405	  If in doubt, say Y.
406
407config X86_X2APIC
408	bool "Support x2apic"
409	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
410	---help---
411	  This enables x2apic support on CPUs that have this feature.
412
413	  This allows 32-bit apic IDs (so it can support very large systems),
414	  and accesses the local apic via MSRs not via mmio.
415
416	  If you don't know what to do here, say N.
417
418config X86_MPPARSE
419	bool "Enable MPS table" if ACPI || SFI
420	default y
421	depends on X86_LOCAL_APIC
422	---help---
423	  For old smp systems that do not have proper acpi support. Newer systems
424	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
425
426config GOLDFISH
427       def_bool y
428       depends on X86_GOLDFISH
429
430config RETPOLINE
431	bool "Avoid speculative indirect branches in kernel"
432	default y
433	select STACK_VALIDATION if HAVE_STACK_VALIDATION
434	help
435	  Compile kernel with the retpoline compiler options to guard against
436	  kernel-to-user data leaks by avoiding speculative indirect
437	  branches. Requires a compiler with -mindirect-branch=thunk-extern
438	  support for full protection. The kernel may run slower.
439
440config X86_CPU_RESCTRL
441	bool "x86 CPU resource control support"
442	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
443	select KERNFS
444	help
445	  Enable x86 CPU resource control support.
446
447	  Provide support for the allocation and monitoring of system resources
448	  usage by the CPU.
449
450	  Intel calls this Intel Resource Director Technology
451	  (Intel(R) RDT). More information about RDT can be found in the
452	  Intel x86 Architecture Software Developer Manual.
453
454	  AMD calls this AMD Platform Quality of Service (AMD QoS).
455	  More information about AMD QoS can be found in the AMD64 Technology
456	  Platform Quality of Service Extensions manual.
457
458	  Say N if unsure.
459
460if X86_32
461config X86_BIGSMP
462	bool "Support for big SMP systems with more than 8 CPUs"
463	depends on SMP
464	---help---
465	  This option is needed for the systems that have more than 8 CPUs
466
467config X86_EXTENDED_PLATFORM
468	bool "Support for extended (non-PC) x86 platforms"
469	default y
470	---help---
471	  If you disable this option then the kernel will only support
472	  standard PC platforms. (which covers the vast majority of
473	  systems out there.)
474
475	  If you enable this option then you'll be able to select support
476	  for the following (non-PC) 32 bit x86 platforms:
477		Goldfish (Android emulator)
478		AMD Elan
479		RDC R-321x SoC
480		SGI 320/540 (Visual Workstation)
481		STA2X11-based (e.g. Northville)
482		Moorestown MID devices
483
484	  If you have one of these systems, or if you want to build a
485	  generic distribution kernel, say Y here - otherwise say N.
486endif
487
488if X86_64
489config X86_EXTENDED_PLATFORM
490	bool "Support for extended (non-PC) x86 platforms"
491	default y
492	---help---
493	  If you disable this option then the kernel will only support
494	  standard PC platforms. (which covers the vast majority of
495	  systems out there.)
496
497	  If you enable this option then you'll be able to select support
498	  for the following (non-PC) 64 bit x86 platforms:
499		Numascale NumaChip
500		ScaleMP vSMP
501		SGI Ultraviolet
502
503	  If you have one of these systems, or if you want to build a
504	  generic distribution kernel, say Y here - otherwise say N.
505endif
506# This is an alphabetically sorted list of 64 bit extended platforms
507# Please maintain the alphabetic order if and when there are additions
508config X86_NUMACHIP
509	bool "Numascale NumaChip"
510	depends on X86_64
511	depends on X86_EXTENDED_PLATFORM
512	depends on NUMA
513	depends on SMP
514	depends on X86_X2APIC
515	depends on PCI_MMCONFIG
516	---help---
517	  Adds support for Numascale NumaChip large-SMP systems. Needed to
518	  enable more than ~168 cores.
519	  If you don't have one of these, you should say N here.
520
521config X86_VSMP
522	bool "ScaleMP vSMP"
523	select HYPERVISOR_GUEST
524	select PARAVIRT
525	depends on X86_64 && PCI
526	depends on X86_EXTENDED_PLATFORM
527	depends on SMP
528	---help---
529	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
530	  supposed to run on these EM64T-based machines.  Only choose this option
531	  if you have one of these machines.
532
533config X86_UV
534	bool "SGI Ultraviolet"
535	depends on X86_64
536	depends on X86_EXTENDED_PLATFORM
537	depends on NUMA
538	depends on EFI
539	depends on X86_X2APIC
540	depends on PCI
541	---help---
542	  This option is needed in order to support SGI Ultraviolet systems.
543	  If you don't have one of these, you should say N here.
544
545# Following is an alphabetically sorted list of 32 bit extended platforms
546# Please maintain the alphabetic order if and when there are additions
547
548config X86_GOLDFISH
549       bool "Goldfish (Virtual Platform)"
550       depends on X86_EXTENDED_PLATFORM
551       ---help---
552	 Enable support for the Goldfish virtual platform used primarily
553	 for Android development. Unless you are building for the Android
554	 Goldfish emulator say N here.
555
556config X86_INTEL_CE
557	bool "CE4100 TV platform"
558	depends on PCI
559	depends on PCI_GODIRECT
560	depends on X86_IO_APIC
561	depends on X86_32
562	depends on X86_EXTENDED_PLATFORM
563	select X86_REBOOTFIXUPS
564	select OF
565	select OF_EARLY_FLATTREE
566	---help---
567	  Select for the Intel CE media processor (CE4100) SOC.
568	  This option compiles in support for the CE4100 SOC for settop
569	  boxes and media devices.
570
571config X86_INTEL_MID
572	bool "Intel MID platform support"
573	depends on X86_EXTENDED_PLATFORM
574	depends on X86_PLATFORM_DEVICES
575	depends on PCI
576	depends on X86_64 || (PCI_GOANY && X86_32)
577	depends on X86_IO_APIC
578	select SFI
579	select I2C
580	select DW_APB_TIMER
581	select APB_TIMER
582	select INTEL_SCU_IPC
583	select MFD_INTEL_MSIC
584	---help---
585	  Select to build a kernel capable of supporting Intel MID (Mobile
586	  Internet Device) platform systems which do not have the PCI legacy
587	  interfaces. If you are building for a PC class system say N here.
588
589	  Intel MID platforms are based on an Intel processor and chipset which
590	  consume less power than most of the x86 derivatives.
591
592config X86_INTEL_QUARK
593	bool "Intel Quark platform support"
594	depends on X86_32
595	depends on X86_EXTENDED_PLATFORM
596	depends on X86_PLATFORM_DEVICES
597	depends on X86_TSC
598	depends on PCI
599	depends on PCI_GOANY
600	depends on X86_IO_APIC
601	select IOSF_MBI
602	select INTEL_IMR
603	select COMMON_CLK
604	---help---
605	  Select to include support for Quark X1000 SoC.
606	  Say Y here if you have a Quark based system such as the Arduino
607	  compatible Intel Galileo.
608
609config X86_INTEL_LPSS
610	bool "Intel Low Power Subsystem Support"
611	depends on X86 && ACPI && PCI
612	select COMMON_CLK
613	select PINCTRL
614	select IOSF_MBI
615	---help---
616	  Select to build support for Intel Low Power Subsystem such as
617	  found on Intel Lynxpoint PCH. Selecting this option enables
618	  things like clock tree (common clock framework) and pincontrol
619	  which are needed by the LPSS peripheral drivers.
620
621config X86_AMD_PLATFORM_DEVICE
622	bool "AMD ACPI2Platform devices support"
623	depends on ACPI
624	select COMMON_CLK
625	select PINCTRL
626	---help---
627	  Select to interpret AMD specific ACPI device to platform device
628	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
629	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
630	  implemented under PINCTRL subsystem.
631
632config IOSF_MBI
633	tristate "Intel SoC IOSF Sideband support for SoC platforms"
634	depends on PCI
635	---help---
636	  This option enables sideband register access support for Intel SoC
637	  platforms. On these platforms the IOSF sideband is used in lieu of
638	  MSR's for some register accesses, mostly but not limited to thermal
639	  and power. Drivers may query the availability of this device to
640	  determine if they need the sideband in order to work on these
641	  platforms. The sideband is available on the following SoC products.
642	  This list is not meant to be exclusive.
643	   - BayTrail
644	   - Braswell
645	   - Quark
646
647	  You should say Y if you are running a kernel on one of these SoC's.
648
649config IOSF_MBI_DEBUG
650	bool "Enable IOSF sideband access through debugfs"
651	depends on IOSF_MBI && DEBUG_FS
652	---help---
653	  Select this option to expose the IOSF sideband access registers (MCR,
654	  MDR, MCRX) through debugfs to write and read register information from
655	  different units on the SoC. This is most useful for obtaining device
656	  state information for debug and analysis. As this is a general access
657	  mechanism, users of this option would have specific knowledge of the
658	  device they want to access.
659
660	  If you don't require the option or are in doubt, say N.
661
662config X86_RDC321X
663	bool "RDC R-321x SoC"
664	depends on X86_32
665	depends on X86_EXTENDED_PLATFORM
666	select M486
667	select X86_REBOOTFIXUPS
668	---help---
669	  This option is needed for RDC R-321x system-on-chip, also known
670	  as R-8610-(G).
671	  If you don't have one of these chips, you should say N here.
672
673config X86_32_NON_STANDARD
674	bool "Support non-standard 32-bit SMP architectures"
675	depends on X86_32 && SMP
676	depends on X86_EXTENDED_PLATFORM
677	---help---
678	  This option compiles in the bigsmp and STA2X11 default
679	  subarchitectures.  It is intended for a generic binary
680	  kernel. If you select them all, kernel will probe it one by
681	  one and will fallback to default.
682
683# Alphabetically sorted list of Non standard 32 bit platforms
684
685config X86_SUPPORTS_MEMORY_FAILURE
686	def_bool y
687	# MCE code calls memory_failure():
688	depends on X86_MCE
689	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
690	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
691	depends on X86_64 || !SPARSEMEM
692	select ARCH_SUPPORTS_MEMORY_FAILURE
693
694config STA2X11
695	bool "STA2X11 Companion Chip Support"
696	depends on X86_32_NON_STANDARD && PCI
697	select ARCH_HAS_PHYS_TO_DMA
698	select SWIOTLB
699	select MFD_STA2X11
700	select GPIOLIB
701	---help---
702	  This adds support for boards based on the STA2X11 IO-Hub,
703	  a.k.a. "ConneXt". The chip is used in place of the standard
704	  PC chipset, so all "standard" peripherals are missing. If this
705	  option is selected the kernel will still be able to boot on
706	  standard PC machines.
707
708config X86_32_IRIS
709	tristate "Eurobraille/Iris poweroff module"
710	depends on X86_32
711	---help---
712	  The Iris machines from EuroBraille do not have APM or ACPI support
713	  to shut themselves down properly.  A special I/O sequence is
714	  needed to do so, which is what this module does at
715	  kernel shutdown.
716
717	  This is only for Iris machines from EuroBraille.
718
719	  If unused, say N.
720
721config SCHED_OMIT_FRAME_POINTER
722	def_bool y
723	prompt "Single-depth WCHAN output"
724	depends on X86
725	---help---
726	  Calculate simpler /proc/<PID>/wchan values. If this option
727	  is disabled then wchan values will recurse back to the
728	  caller function. This provides more accurate wchan values,
729	  at the expense of slightly more scheduling overhead.
730
731	  If in doubt, say "Y".
732
733menuconfig HYPERVISOR_GUEST
734	bool "Linux guest support"
735	---help---
736	  Say Y here to enable options for running Linux under various hyper-
737	  visors. This option enables basic hypervisor detection and platform
738	  setup.
739
740	  If you say N, all options in this submenu will be skipped and
741	  disabled, and Linux guest support won't be built in.
742
743if HYPERVISOR_GUEST
744
745config PARAVIRT
746	bool "Enable paravirtualization code"
747	---help---
748	  This changes the kernel so it can modify itself when it is run
749	  under a hypervisor, potentially improving performance significantly
750	  over full virtualization.  However, when run without a hypervisor
751	  the kernel is theoretically slower and slightly larger.
752
753config PARAVIRT_XXL
754	bool
755
756config PARAVIRT_DEBUG
757	bool "paravirt-ops debugging"
758	depends on PARAVIRT && DEBUG_KERNEL
759	---help---
760	  Enable to debug paravirt_ops internals.  Specifically, BUG if
761	  a paravirt_op is missing when it is called.
762
763config PARAVIRT_SPINLOCKS
764	bool "Paravirtualization layer for spinlocks"
765	depends on PARAVIRT && SMP
766	---help---
767	  Paravirtualized spinlocks allow a pvops backend to replace the
768	  spinlock implementation with something virtualization-friendly
769	  (for example, block the virtual CPU rather than spinning).
770
771	  It has a minimal impact on native kernels and gives a nice performance
772	  benefit on paravirtualized KVM / Xen kernels.
773
774	  If you are unsure how to answer this question, answer Y.
775
776source "arch/x86/xen/Kconfig"
777
778config KVM_GUEST
779	bool "KVM Guest support (including kvmclock)"
780	depends on PARAVIRT
781	select PARAVIRT_CLOCK
782	default y
783	---help---
784	  This option enables various optimizations for running under the KVM
785	  hypervisor. It includes a paravirtualized clock, so that instead
786	  of relying on a PIT (or probably other) emulation by the
787	  underlying device model, the host provides the guest with
788	  timing infrastructure such as time of day, and system time
789
790config PVH
791	bool "Support for running PVH guests"
792	---help---
793	  This option enables the PVH entry point for guest virtual machines
794	  as specified in the x86/HVM direct boot ABI.
795
796config KVM_DEBUG_FS
797	bool "Enable debug information for KVM Guests in debugfs"
798	depends on KVM_GUEST && DEBUG_FS
799	---help---
800	  This option enables collection of various statistics for KVM guest.
801	  Statistics are displayed in debugfs filesystem. Enabling this option
802	  may incur significant overhead.
803
804config PARAVIRT_TIME_ACCOUNTING
805	bool "Paravirtual steal time accounting"
806	depends on PARAVIRT
807	---help---
808	  Select this option to enable fine granularity task steal time
809	  accounting. Time spent executing other tasks in parallel with
810	  the current vCPU is discounted from the vCPU power. To account for
811	  that, there can be a small performance impact.
812
813	  If in doubt, say N here.
814
815config PARAVIRT_CLOCK
816	bool
817
818config JAILHOUSE_GUEST
819	bool "Jailhouse non-root cell support"
820	depends on X86_64 && PCI
821	select X86_PM_TIMER
822	---help---
823	  This option allows to run Linux as guest in a Jailhouse non-root
824	  cell. You can leave this option disabled if you only want to start
825	  Jailhouse and run Linux afterwards in the root cell.
826
827endif #HYPERVISOR_GUEST
828
829source "arch/x86/Kconfig.cpu"
830
831config HPET_TIMER
832	def_bool X86_64
833	prompt "HPET Timer Support" if X86_32
834	---help---
835	  Use the IA-PC HPET (High Precision Event Timer) to manage
836	  time in preference to the PIT and RTC, if a HPET is
837	  present.
838	  HPET is the next generation timer replacing legacy 8254s.
839	  The HPET provides a stable time base on SMP
840	  systems, unlike the TSC, but it is more expensive to access,
841	  as it is off-chip.  The interface used is documented
842	  in the HPET spec, revision 1.
843
844	  You can safely choose Y here.  However, HPET will only be
845	  activated if the platform and the BIOS support this feature.
846	  Otherwise the 8254 will be used for timing services.
847
848	  Choose N to continue using the legacy 8254 timer.
849
850config HPET_EMULATE_RTC
851	def_bool y
852	depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
853
854config APB_TIMER
855       def_bool y if X86_INTEL_MID
856       prompt "Intel MID APB Timer Support" if X86_INTEL_MID
857       select DW_APB_TIMER
858       depends on X86_INTEL_MID && SFI
859       help
860         APB timer is the replacement for 8254, HPET on X86 MID platforms.
861         The APBT provides a stable time base on SMP
862         systems, unlike the TSC, but it is more expensive to access,
863         as it is off-chip. APB timers are always running regardless of CPU
864         C states, they are used as per CPU clockevent device when possible.
865
866# Mark as expert because too many people got it wrong.
867# The code disables itself when not needed.
868config DMI
869	default y
870	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
871	bool "Enable DMI scanning" if EXPERT
872	---help---
873	  Enabled scanning of DMI to identify machine quirks. Say Y
874	  here unless you have verified that your setup is not
875	  affected by entries in the DMI blacklist. Required by PNP
876	  BIOS code.
877
878config GART_IOMMU
879	bool "Old AMD GART IOMMU support"
880	select IOMMU_HELPER
881	select SWIOTLB
882	depends on X86_64 && PCI && AMD_NB
883	---help---
884	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
885	  GART based hardware IOMMUs.
886
887	  The GART supports full DMA access for devices with 32-bit access
888	  limitations, on systems with more than 3 GB. This is usually needed
889	  for USB, sound, many IDE/SATA chipsets and some other devices.
890
891	  Newer systems typically have a modern AMD IOMMU, supported via
892	  the CONFIG_AMD_IOMMU=y config option.
893
894	  In normal configurations this driver is only active when needed:
895	  there's more than 3 GB of memory and the system contains a
896	  32-bit limited device.
897
898	  If unsure, say Y.
899
900config CALGARY_IOMMU
901	bool "IBM Calgary IOMMU support"
902	select IOMMU_HELPER
903	select SWIOTLB
904	depends on X86_64 && PCI
905	---help---
906	  Support for hardware IOMMUs in IBM's xSeries x366 and x460
907	  systems. Needed to run systems with more than 3GB of memory
908	  properly with 32-bit PCI devices that do not support DAC
909	  (Double Address Cycle). Calgary also supports bus level
910	  isolation, where all DMAs pass through the IOMMU.  This
911	  prevents them from going anywhere except their intended
912	  destination. This catches hard-to-find kernel bugs and
913	  mis-behaving drivers and devices that do not use the DMA-API
914	  properly to set up their DMA buffers.  The IOMMU can be
915	  turned off at boot time with the iommu=off parameter.
916	  Normally the kernel will make the right choice by itself.
917	  If unsure, say Y.
918
919config CALGARY_IOMMU_ENABLED_BY_DEFAULT
920	def_bool y
921	prompt "Should Calgary be enabled by default?"
922	depends on CALGARY_IOMMU
923	---help---
924	  Should Calgary be enabled by default? if you choose 'y', Calgary
925	  will be used (if it exists). If you choose 'n', Calgary will not be
926	  used even if it exists. If you choose 'n' and would like to use
927	  Calgary anyway, pass 'iommu=calgary' on the kernel command line.
928	  If unsure, say Y.
929
930config MAXSMP
931	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
932	depends on X86_64 && SMP && DEBUG_KERNEL
933	select CPUMASK_OFFSTACK
934	---help---
935	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
936	  If unsure, say N.
937
938#
939# The maximum number of CPUs supported:
940#
941# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
942# and which can be configured interactively in the
943# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
944#
945# The ranges are different on 32-bit and 64-bit kernels, depending on
946# hardware capabilities and scalability features of the kernel.
947#
948# ( If MAXSMP is enabled we just use the highest possible value and disable
949#   interactive configuration. )
950#
951
952config NR_CPUS_RANGE_BEGIN
953	int
954	default NR_CPUS_RANGE_END if MAXSMP
955	default    1 if !SMP
956	default    2
957
958config NR_CPUS_RANGE_END
959	int
960	depends on X86_32
961	default   64 if  SMP &&  X86_BIGSMP
962	default    8 if  SMP && !X86_BIGSMP
963	default    1 if !SMP
964
965config NR_CPUS_RANGE_END
966	int
967	depends on X86_64
968	default 8192 if  SMP && ( MAXSMP ||  CPUMASK_OFFSTACK)
969	default  512 if  SMP && (!MAXSMP && !CPUMASK_OFFSTACK)
970	default    1 if !SMP
971
972config NR_CPUS_DEFAULT
973	int
974	depends on X86_32
975	default   32 if  X86_BIGSMP
976	default    8 if  SMP
977	default    1 if !SMP
978
979config NR_CPUS_DEFAULT
980	int
981	depends on X86_64
982	default 8192 if  MAXSMP
983	default   64 if  SMP
984	default    1 if !SMP
985
986config NR_CPUS
987	int "Maximum number of CPUs" if SMP && !MAXSMP
988	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
989	default NR_CPUS_DEFAULT
990	---help---
991	  This allows you to specify the maximum number of CPUs which this
992	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
993	  supported value is 8192, otherwise the maximum value is 512.  The
994	  minimum value which makes sense is 2.
995
996	  This is purely to save memory: each supported CPU adds about 8KB
997	  to the kernel image.
998
999config SCHED_SMT
1000	def_bool y if SMP
1001
1002config SCHED_MC
1003	def_bool y
1004	prompt "Multi-core scheduler support"
1005	depends on SMP
1006	---help---
1007	  Multi-core scheduler support improves the CPU scheduler's decision
1008	  making when dealing with multi-core CPU chips at a cost of slightly
1009	  increased overhead in some places. If unsure say N here.
1010
1011config SCHED_MC_PRIO
1012	bool "CPU core priorities scheduler support"
1013	depends on SCHED_MC && CPU_SUP_INTEL
1014	select X86_INTEL_PSTATE
1015	select CPU_FREQ
1016	default y
1017	---help---
1018	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1019	  core ordering determined at manufacturing time, which allows
1020	  certain cores to reach higher turbo frequencies (when running
1021	  single threaded workloads) than others.
1022
1023	  Enabling this kernel feature teaches the scheduler about
1024	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1025	  scheduler's CPU selection logic accordingly, so that higher
1026	  overall system performance can be achieved.
1027
1028	  This feature will have no effect on CPUs without this feature.
1029
1030	  If unsure say Y here.
1031
1032config UP_LATE_INIT
1033       def_bool y
1034       depends on !SMP && X86_LOCAL_APIC
1035
1036config X86_UP_APIC
1037	bool "Local APIC support on uniprocessors" if !PCI_MSI
1038	default PCI_MSI
1039	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1040	---help---
1041	  A local APIC (Advanced Programmable Interrupt Controller) is an
1042	  integrated interrupt controller in the CPU. If you have a single-CPU
1043	  system which has a processor with a local APIC, you can say Y here to
1044	  enable and use it. If you say Y here even though your machine doesn't
1045	  have a local APIC, then the kernel will still run with no slowdown at
1046	  all. The local APIC supports CPU-generated self-interrupts (timer,
1047	  performance counters), and the NMI watchdog which detects hard
1048	  lockups.
1049
1050config X86_UP_IOAPIC
1051	bool "IO-APIC support on uniprocessors"
1052	depends on X86_UP_APIC
1053	---help---
1054	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1055	  SMP-capable replacement for PC-style interrupt controllers. Most
1056	  SMP systems and many recent uniprocessor systems have one.
1057
1058	  If you have a single-CPU system with an IO-APIC, you can say Y here
1059	  to use it. If you say Y here even though your machine doesn't have
1060	  an IO-APIC, then the kernel will still run with no slowdown at all.
1061
1062config X86_LOCAL_APIC
1063	def_bool y
1064	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1065	select IRQ_DOMAIN_HIERARCHY
1066	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1067
1068config X86_IO_APIC
1069	def_bool y
1070	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1071
1072config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1073	bool "Reroute for broken boot IRQs"
1074	depends on X86_IO_APIC
1075	---help---
1076	  This option enables a workaround that fixes a source of
1077	  spurious interrupts. This is recommended when threaded
1078	  interrupt handling is used on systems where the generation of
1079	  superfluous "boot interrupts" cannot be disabled.
1080
1081	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1082	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1083	  kernel does during interrupt handling). On chipsets where this
1084	  boot IRQ generation cannot be disabled, this workaround keeps
1085	  the original IRQ line masked so that only the equivalent "boot
1086	  IRQ" is delivered to the CPUs. The workaround also tells the
1087	  kernel to set up the IRQ handler on the boot IRQ line. In this
1088	  way only one interrupt is delivered to the kernel. Otherwise
1089	  the spurious second interrupt may cause the kernel to bring
1090	  down (vital) interrupt lines.
1091
1092	  Only affects "broken" chipsets. Interrupt sharing may be
1093	  increased on these systems.
1094
1095config X86_MCE
1096	bool "Machine Check / overheating reporting"
1097	select GENERIC_ALLOCATOR
1098	default y
1099	---help---
1100	  Machine Check support allows the processor to notify the
1101	  kernel if it detects a problem (e.g. overheating, data corruption).
1102	  The action the kernel takes depends on the severity of the problem,
1103	  ranging from warning messages to halting the machine.
1104
1105config X86_MCELOG_LEGACY
1106	bool "Support for deprecated /dev/mcelog character device"
1107	depends on X86_MCE
1108	---help---
1109	  Enable support for /dev/mcelog which is needed by the old mcelog
1110	  userspace logging daemon. Consider switching to the new generation
1111	  rasdaemon solution.
1112
1113config X86_MCE_INTEL
1114	def_bool y
1115	prompt "Intel MCE features"
1116	depends on X86_MCE && X86_LOCAL_APIC
1117	---help---
1118	   Additional support for intel specific MCE features such as
1119	   the thermal monitor.
1120
1121config X86_MCE_AMD
1122	def_bool y
1123	prompt "AMD MCE features"
1124	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1125	---help---
1126	   Additional support for AMD specific MCE features such as
1127	   the DRAM Error Threshold.
1128
1129config X86_ANCIENT_MCE
1130	bool "Support for old Pentium 5 / WinChip machine checks"
1131	depends on X86_32 && X86_MCE
1132	---help---
1133	  Include support for machine check handling on old Pentium 5 or WinChip
1134	  systems. These typically need to be enabled explicitly on the command
1135	  line.
1136
1137config X86_MCE_THRESHOLD
1138	depends on X86_MCE_AMD || X86_MCE_INTEL
1139	def_bool y
1140
1141config X86_MCE_INJECT
1142	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1143	tristate "Machine check injector support"
1144	---help---
1145	  Provide support for injecting machine checks for testing purposes.
1146	  If you don't know what a machine check is and you don't do kernel
1147	  QA it is safe to say n.
1148
1149config X86_THERMAL_VECTOR
1150	def_bool y
1151	depends on X86_MCE_INTEL
1152
1153source "arch/x86/events/Kconfig"
1154
1155config X86_LEGACY_VM86
1156	bool "Legacy VM86 support"
1157	depends on X86_32
1158	---help---
1159	  This option allows user programs to put the CPU into V8086
1160	  mode, which is an 80286-era approximation of 16-bit real mode.
1161
1162	  Some very old versions of X and/or vbetool require this option
1163	  for user mode setting.  Similarly, DOSEMU will use it if
1164	  available to accelerate real mode DOS programs.  However, any
1165	  recent version of DOSEMU, X, or vbetool should be fully
1166	  functional even without kernel VM86 support, as they will all
1167	  fall back to software emulation. Nevertheless, if you are using
1168	  a 16-bit DOS program where 16-bit performance matters, vm86
1169	  mode might be faster than emulation and you might want to
1170	  enable this option.
1171
1172	  Note that any app that works on a 64-bit kernel is unlikely to
1173	  need this option, as 64-bit kernels don't, and can't, support
1174	  V8086 mode. This option is also unrelated to 16-bit protected
1175	  mode and is not needed to run most 16-bit programs under Wine.
1176
1177	  Enabling this option increases the complexity of the kernel
1178	  and slows down exception handling a tiny bit.
1179
1180	  If unsure, say N here.
1181
1182config VM86
1183       bool
1184       default X86_LEGACY_VM86
1185
1186config X86_16BIT
1187	bool "Enable support for 16-bit segments" if EXPERT
1188	default y
1189	depends on MODIFY_LDT_SYSCALL
1190	---help---
1191	  This option is required by programs like Wine to run 16-bit
1192	  protected mode legacy code on x86 processors.  Disabling
1193	  this option saves about 300 bytes on i386, or around 6K text
1194	  plus 16K runtime memory on x86-64,
1195
1196config X86_ESPFIX32
1197	def_bool y
1198	depends on X86_16BIT && X86_32
1199
1200config X86_ESPFIX64
1201	def_bool y
1202	depends on X86_16BIT && X86_64
1203
1204config X86_VSYSCALL_EMULATION
1205       bool "Enable vsyscall emulation" if EXPERT
1206       default y
1207       depends on X86_64
1208       ---help---
1209	 This enables emulation of the legacy vsyscall page.  Disabling
1210	 it is roughly equivalent to booting with vsyscall=none, except
1211	 that it will also disable the helpful warning if a program
1212	 tries to use a vsyscall.  With this option set to N, offending
1213	 programs will just segfault, citing addresses of the form
1214	 0xffffffffff600?00.
1215
1216	 This option is required by many programs built before 2013, and
1217	 care should be used even with newer programs if set to N.
1218
1219	 Disabling this option saves about 7K of kernel size and
1220	 possibly 4K of additional runtime pagetable memory.
1221
1222config TOSHIBA
1223	tristate "Toshiba Laptop support"
1224	depends on X86_32
1225	---help---
1226	  This adds a driver to safely access the System Management Mode of
1227	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1228	  not work on models with a Phoenix BIOS. The System Management Mode
1229	  is used to set the BIOS and power saving options on Toshiba portables.
1230
1231	  For information on utilities to make use of this driver see the
1232	  Toshiba Linux utilities web site at:
1233	  <http://www.buzzard.org.uk/toshiba/>.
1234
1235	  Say Y if you intend to run this kernel on a Toshiba portable.
1236	  Say N otherwise.
1237
1238config I8K
1239	tristate "Dell i8k legacy laptop support"
1240	select HWMON
1241	select SENSORS_DELL_SMM
1242	---help---
1243	  This option enables legacy /proc/i8k userspace interface in hwmon
1244	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1245	  temperature and allows controlling fan speeds of Dell laptops via
1246	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1247	  it reports also power and hotkey status. For fan speed control is
1248	  needed userspace package i8kutils.
1249
1250	  Say Y if you intend to run this kernel on old Dell laptops or want to
1251	  use userspace package i8kutils.
1252	  Say N otherwise.
1253
1254config X86_REBOOTFIXUPS
1255	bool "Enable X86 board specific fixups for reboot"
1256	depends on X86_32
1257	---help---
1258	  This enables chipset and/or board specific fixups to be done
1259	  in order to get reboot to work correctly. This is only needed on
1260	  some combinations of hardware and BIOS. The symptom, for which
1261	  this config is intended, is when reboot ends with a stalled/hung
1262	  system.
1263
1264	  Currently, the only fixup is for the Geode machines using
1265	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1266
1267	  Say Y if you want to enable the fixup. Currently, it's safe to
1268	  enable this option even if you don't need it.
1269	  Say N otherwise.
1270
1271config MICROCODE
1272	bool "CPU microcode loading support"
1273	default y
1274	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1275	select FW_LOADER
1276	---help---
1277	  If you say Y here, you will be able to update the microcode on
1278	  Intel and AMD processors. The Intel support is for the IA32 family,
1279	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1280	  AMD support is for families 0x10 and later. You will obviously need
1281	  the actual microcode binary data itself which is not shipped with
1282	  the Linux kernel.
1283
1284	  The preferred method to load microcode from a detached initrd is described
1285	  in Documentation/x86/microcode.txt. For that you need to enable
1286	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1287	  initrd for microcode blobs.
1288
1289	  In addition, you can build the microcode into the kernel. For that you
1290	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1291	  config option.
1292
1293config MICROCODE_INTEL
1294	bool "Intel microcode loading support"
1295	depends on MICROCODE
1296	default MICROCODE
1297	select FW_LOADER
1298	---help---
1299	  This options enables microcode patch loading support for Intel
1300	  processors.
1301
1302	  For the current Intel microcode data package go to
1303	  <https://downloadcenter.intel.com> and search for
1304	  'Linux Processor Microcode Data File'.
1305
1306config MICROCODE_AMD
1307	bool "AMD microcode loading support"
1308	depends on MICROCODE
1309	select FW_LOADER
1310	---help---
1311	  If you select this option, microcode patch loading support for AMD
1312	  processors will be enabled.
1313
1314config MICROCODE_OLD_INTERFACE
1315	bool "Ancient loading interface (DEPRECATED)"
1316	default n
1317	depends on MICROCODE
1318	---help---
1319	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1320	  which was used by userspace tools like iucode_tool and microcode.ctl.
1321	  It is inadequate because it runs too late to be able to properly
1322	  load microcode on a machine and it needs special tools. Instead, you
1323	  should've switched to the early loading method with the initrd or
1324	  builtin microcode by now: Documentation/x86/microcode.txt
1325
1326config X86_MSR
1327	tristate "/dev/cpu/*/msr - Model-specific register support"
1328	---help---
1329	  This device gives privileged processes access to the x86
1330	  Model-Specific Registers (MSRs).  It is a character device with
1331	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1332	  MSR accesses are directed to a specific CPU on multi-processor
1333	  systems.
1334
1335config X86_CPUID
1336	tristate "/dev/cpu/*/cpuid - CPU information support"
1337	---help---
1338	  This device gives processes access to the x86 CPUID instruction to
1339	  be executed on a specific processor.  It is a character device
1340	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1341	  /dev/cpu/31/cpuid.
1342
1343choice
1344	prompt "High Memory Support"
1345	default HIGHMEM4G
1346	depends on X86_32
1347
1348config NOHIGHMEM
1349	bool "off"
1350	---help---
1351	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1352	  However, the address space of 32-bit x86 processors is only 4
1353	  Gigabytes large. That means that, if you have a large amount of
1354	  physical memory, not all of it can be "permanently mapped" by the
1355	  kernel. The physical memory that's not permanently mapped is called
1356	  "high memory".
1357
1358	  If you are compiling a kernel which will never run on a machine with
1359	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1360	  choice and suitable for most users). This will result in a "3GB/1GB"
1361	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1362	  space and the remaining part of the 4GB virtual memory space is used
1363	  by the kernel to permanently map as much physical memory as
1364	  possible.
1365
1366	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1367	  answer "4GB" here.
1368
1369	  If more than 4 Gigabytes is used then answer "64GB" here. This
1370	  selection turns Intel PAE (Physical Address Extension) mode on.
1371	  PAE implements 3-level paging on IA32 processors. PAE is fully
1372	  supported by Linux, PAE mode is implemented on all recent Intel
1373	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1374	  then the kernel will not boot on CPUs that don't support PAE!
1375
1376	  The actual amount of total physical memory will either be
1377	  auto detected or can be forced by using a kernel command line option
1378	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1379	  your boot loader (lilo or loadlin) about how to pass options to the
1380	  kernel at boot time.)
1381
1382	  If unsure, say "off".
1383
1384config HIGHMEM4G
1385	bool "4GB"
1386	---help---
1387	  Select this if you have a 32-bit processor and between 1 and 4
1388	  gigabytes of physical RAM.
1389
1390config HIGHMEM64G
1391	bool "64GB"
1392	depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1393	select X86_PAE
1394	---help---
1395	  Select this if you have a 32-bit processor and more than 4
1396	  gigabytes of physical RAM.
1397
1398endchoice
1399
1400choice
1401	prompt "Memory split" if EXPERT
1402	default VMSPLIT_3G
1403	depends on X86_32
1404	---help---
1405	  Select the desired split between kernel and user memory.
1406
1407	  If the address range available to the kernel is less than the
1408	  physical memory installed, the remaining memory will be available
1409	  as "high memory". Accessing high memory is a little more costly
1410	  than low memory, as it needs to be mapped into the kernel first.
1411	  Note that increasing the kernel address space limits the range
1412	  available to user programs, making the address space there
1413	  tighter.  Selecting anything other than the default 3G/1G split
1414	  will also likely make your kernel incompatible with binary-only
1415	  kernel modules.
1416
1417	  If you are not absolutely sure what you are doing, leave this
1418	  option alone!
1419
1420	config VMSPLIT_3G
1421		bool "3G/1G user/kernel split"
1422	config VMSPLIT_3G_OPT
1423		depends on !X86_PAE
1424		bool "3G/1G user/kernel split (for full 1G low memory)"
1425	config VMSPLIT_2G
1426		bool "2G/2G user/kernel split"
1427	config VMSPLIT_2G_OPT
1428		depends on !X86_PAE
1429		bool "2G/2G user/kernel split (for full 2G low memory)"
1430	config VMSPLIT_1G
1431		bool "1G/3G user/kernel split"
1432endchoice
1433
1434config PAGE_OFFSET
1435	hex
1436	default 0xB0000000 if VMSPLIT_3G_OPT
1437	default 0x80000000 if VMSPLIT_2G
1438	default 0x78000000 if VMSPLIT_2G_OPT
1439	default 0x40000000 if VMSPLIT_1G
1440	default 0xC0000000
1441	depends on X86_32
1442
1443config HIGHMEM
1444	def_bool y
1445	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1446
1447config X86_PAE
1448	bool "PAE (Physical Address Extension) Support"
1449	depends on X86_32 && !HIGHMEM4G
1450	select PHYS_ADDR_T_64BIT
1451	select SWIOTLB
1452	---help---
1453	  PAE is required for NX support, and furthermore enables
1454	  larger swapspace support for non-overcommit purposes. It
1455	  has the cost of more pagetable lookup overhead, and also
1456	  consumes more pagetable space per process.
1457
1458config X86_5LEVEL
1459	bool "Enable 5-level page tables support"
1460	select DYNAMIC_MEMORY_LAYOUT
1461	select SPARSEMEM_VMEMMAP
1462	depends on X86_64
1463	---help---
1464	  5-level paging enables access to larger address space:
1465	  upto 128 PiB of virtual address space and 4 PiB of
1466	  physical address space.
1467
1468	  It will be supported by future Intel CPUs.
1469
1470	  A kernel with the option enabled can be booted on machines that
1471	  support 4- or 5-level paging.
1472
1473	  See Documentation/x86/x86_64/5level-paging.txt for more
1474	  information.
1475
1476	  Say N if unsure.
1477
1478config X86_DIRECT_GBPAGES
1479	def_bool y
1480	depends on X86_64 && !DEBUG_PAGEALLOC
1481	---help---
1482	  Certain kernel features effectively disable kernel
1483	  linear 1 GB mappings (even if the CPU otherwise
1484	  supports them), so don't confuse the user by printing
1485	  that we have them enabled.
1486
1487config X86_CPA_STATISTICS
1488	bool "Enable statistic for Change Page Attribute"
1489	depends on DEBUG_FS
1490	---help---
1491	  Expose statistics about the Change Page Attribute mechanims, which
1492	  helps to determine the effectiveness of preserving large and huge
1493	  page mappings when mapping protections are changed.
1494
1495config ARCH_HAS_MEM_ENCRYPT
1496	def_bool y
1497
1498config AMD_MEM_ENCRYPT
1499	bool "AMD Secure Memory Encryption (SME) support"
1500	depends on X86_64 && CPU_SUP_AMD
1501	select DYNAMIC_PHYSICAL_MASK
1502	select ARCH_USE_MEMREMAP_PROT
1503	---help---
1504	  Say yes to enable support for the encryption of system memory.
1505	  This requires an AMD processor that supports Secure Memory
1506	  Encryption (SME).
1507
1508config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1509	bool "Activate AMD Secure Memory Encryption (SME) by default"
1510	default y
1511	depends on AMD_MEM_ENCRYPT
1512	---help---
1513	  Say yes to have system memory encrypted by default if running on
1514	  an AMD processor that supports Secure Memory Encryption (SME).
1515
1516	  If set to Y, then the encryption of system memory can be
1517	  deactivated with the mem_encrypt=off command line option.
1518
1519	  If set to N, then the encryption of system memory can be
1520	  activated with the mem_encrypt=on command line option.
1521
1522# Common NUMA Features
1523config NUMA
1524	bool "Numa Memory Allocation and Scheduler Support"
1525	depends on SMP
1526	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1527	default y if X86_BIGSMP
1528	---help---
1529	  Enable NUMA (Non Uniform Memory Access) support.
1530
1531	  The kernel will try to allocate memory used by a CPU on the
1532	  local memory controller of the CPU and add some more
1533	  NUMA awareness to the kernel.
1534
1535	  For 64-bit this is recommended if the system is Intel Core i7
1536	  (or later), AMD Opteron, or EM64T NUMA.
1537
1538	  For 32-bit this is only needed if you boot a 32-bit
1539	  kernel on a 64-bit NUMA platform.
1540
1541	  Otherwise, you should say N.
1542
1543config AMD_NUMA
1544	def_bool y
1545	prompt "Old style AMD Opteron NUMA detection"
1546	depends on X86_64 && NUMA && PCI
1547	---help---
1548	  Enable AMD NUMA node topology detection.  You should say Y here if
1549	  you have a multi processor AMD system. This uses an old method to
1550	  read the NUMA configuration directly from the builtin Northbridge
1551	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1552	  which also takes priority if both are compiled in.
1553
1554config X86_64_ACPI_NUMA
1555	def_bool y
1556	prompt "ACPI NUMA detection"
1557	depends on X86_64 && NUMA && ACPI && PCI
1558	select ACPI_NUMA
1559	---help---
1560	  Enable ACPI SRAT based node topology detection.
1561
1562# Some NUMA nodes have memory ranges that span
1563# other nodes.  Even though a pfn is valid and
1564# between a node's start and end pfns, it may not
1565# reside on that node.  See memmap_init_zone()
1566# for details.
1567config NODES_SPAN_OTHER_NODES
1568	def_bool y
1569	depends on X86_64_ACPI_NUMA
1570
1571config NUMA_EMU
1572	bool "NUMA emulation"
1573	depends on NUMA
1574	---help---
1575	  Enable NUMA emulation. A flat machine will be split
1576	  into virtual nodes when booted with "numa=fake=N", where N is the
1577	  number of nodes. This is only useful for debugging.
1578
1579config NODES_SHIFT
1580	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1581	range 1 10
1582	default "10" if MAXSMP
1583	default "6" if X86_64
1584	default "3"
1585	depends on NEED_MULTIPLE_NODES
1586	---help---
1587	  Specify the maximum number of NUMA Nodes available on the target
1588	  system.  Increases memory reserved to accommodate various tables.
1589
1590config ARCH_HAVE_MEMORY_PRESENT
1591	def_bool y
1592	depends on X86_32 && DISCONTIGMEM
1593
1594config ARCH_FLATMEM_ENABLE
1595	def_bool y
1596	depends on X86_32 && !NUMA
1597
1598config ARCH_DISCONTIGMEM_ENABLE
1599	def_bool n
1600	depends on NUMA && X86_32
1601	depends on BROKEN
1602
1603config ARCH_SPARSEMEM_ENABLE
1604	def_bool y
1605	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1606	select SPARSEMEM_STATIC if X86_32
1607	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1608
1609config ARCH_SPARSEMEM_DEFAULT
1610	def_bool X86_64 || (NUMA && X86_32)
1611
1612config ARCH_SELECT_MEMORY_MODEL
1613	def_bool y
1614	depends on ARCH_SPARSEMEM_ENABLE
1615
1616config ARCH_MEMORY_PROBE
1617	bool "Enable sysfs memory/probe interface"
1618	depends on X86_64 && MEMORY_HOTPLUG
1619	help
1620	  This option enables a sysfs memory/probe interface for testing.
1621	  See Documentation/memory-hotplug.txt for more information.
1622	  If you are unsure how to answer this question, answer N.
1623
1624config ARCH_PROC_KCORE_TEXT
1625	def_bool y
1626	depends on X86_64 && PROC_KCORE
1627
1628config ILLEGAL_POINTER_VALUE
1629       hex
1630       default 0 if X86_32
1631       default 0xdead000000000000 if X86_64
1632
1633config X86_PMEM_LEGACY_DEVICE
1634	bool
1635
1636config X86_PMEM_LEGACY
1637	tristate "Support non-standard NVDIMMs and ADR protected memory"
1638	depends on PHYS_ADDR_T_64BIT
1639	depends on BLK_DEV
1640	select X86_PMEM_LEGACY_DEVICE
1641	select LIBNVDIMM
1642	help
1643	  Treat memory marked using the non-standard e820 type of 12 as used
1644	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1645	  The kernel will offer these regions to the 'pmem' driver so
1646	  they can be used for persistent storage.
1647
1648	  Say Y if unsure.
1649
1650config HIGHPTE
1651	bool "Allocate 3rd-level pagetables from highmem"
1652	depends on HIGHMEM
1653	---help---
1654	  The VM uses one page table entry for each page of physical memory.
1655	  For systems with a lot of RAM, this can be wasteful of precious
1656	  low memory.  Setting this option will put user-space page table
1657	  entries in high memory.
1658
1659config X86_CHECK_BIOS_CORRUPTION
1660	bool "Check for low memory corruption"
1661	---help---
1662	  Periodically check for memory corruption in low memory, which
1663	  is suspected to be caused by BIOS.  Even when enabled in the
1664	  configuration, it is disabled at runtime.  Enable it by
1665	  setting "memory_corruption_check=1" on the kernel command
1666	  line.  By default it scans the low 64k of memory every 60
1667	  seconds; see the memory_corruption_check_size and
1668	  memory_corruption_check_period parameters in
1669	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1670
1671	  When enabled with the default parameters, this option has
1672	  almost no overhead, as it reserves a relatively small amount
1673	  of memory and scans it infrequently.  It both detects corruption
1674	  and prevents it from affecting the running system.
1675
1676	  It is, however, intended as a diagnostic tool; if repeatable
1677	  BIOS-originated corruption always affects the same memory,
1678	  you can use memmap= to prevent the kernel from using that
1679	  memory.
1680
1681config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1682	bool "Set the default setting of memory_corruption_check"
1683	depends on X86_CHECK_BIOS_CORRUPTION
1684	default y
1685	---help---
1686	  Set whether the default state of memory_corruption_check is
1687	  on or off.
1688
1689config X86_RESERVE_LOW
1690	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1691	default 64
1692	range 4 640
1693	---help---
1694	  Specify the amount of low memory to reserve for the BIOS.
1695
1696	  The first page contains BIOS data structures that the kernel
1697	  must not use, so that page must always be reserved.
1698
1699	  By default we reserve the first 64K of physical RAM, as a
1700	  number of BIOSes are known to corrupt that memory range
1701	  during events such as suspend/resume or monitor cable
1702	  insertion, so it must not be used by the kernel.
1703
1704	  You can set this to 4 if you are absolutely sure that you
1705	  trust the BIOS to get all its memory reservations and usages
1706	  right.  If you know your BIOS have problems beyond the
1707	  default 64K area, you can set this to 640 to avoid using the
1708	  entire low memory range.
1709
1710	  If you have doubts about the BIOS (e.g. suspend/resume does
1711	  not work or there's kernel crashes after certain hardware
1712	  hotplug events) then you might want to enable
1713	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1714	  typical corruption patterns.
1715
1716	  Leave this to the default value of 64 if you are unsure.
1717
1718config MATH_EMULATION
1719	bool
1720	depends on MODIFY_LDT_SYSCALL
1721	prompt "Math emulation" if X86_32
1722	---help---
1723	  Linux can emulate a math coprocessor (used for floating point
1724	  operations) if you don't have one. 486DX and Pentium processors have
1725	  a math coprocessor built in, 486SX and 386 do not, unless you added
1726	  a 487DX or 387, respectively. (The messages during boot time can
1727	  give you some hints here ["man dmesg"].) Everyone needs either a
1728	  coprocessor or this emulation.
1729
1730	  If you don't have a math coprocessor, you need to say Y here; if you
1731	  say Y here even though you have a coprocessor, the coprocessor will
1732	  be used nevertheless. (This behavior can be changed with the kernel
1733	  command line option "no387", which comes handy if your coprocessor
1734	  is broken. Try "man bootparam" or see the documentation of your boot
1735	  loader (lilo or loadlin) about how to pass options to the kernel at
1736	  boot time.) This means that it is a good idea to say Y here if you
1737	  intend to use this kernel on different machines.
1738
1739	  More information about the internals of the Linux math coprocessor
1740	  emulation can be found in <file:arch/x86/math-emu/README>.
1741
1742	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1743	  kernel, it won't hurt.
1744
1745config MTRR
1746	def_bool y
1747	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1748	---help---
1749	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1750	  the Memory Type Range Registers (MTRRs) may be used to control
1751	  processor access to memory ranges. This is most useful if you have
1752	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1753	  allows bus write transfers to be combined into a larger transfer
1754	  before bursting over the PCI/AGP bus. This can increase performance
1755	  of image write operations 2.5 times or more. Saying Y here creates a
1756	  /proc/mtrr file which may be used to manipulate your processor's
1757	  MTRRs. Typically the X server should use this.
1758
1759	  This code has a reasonably generic interface so that similar
1760	  control registers on other processors can be easily supported
1761	  as well:
1762
1763	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1764	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1765	  these, the ARRs are used to emulate the MTRRs.
1766	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1767	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1768	  write-combining. All of these processors are supported by this code
1769	  and it makes sense to say Y here if you have one of them.
1770
1771	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1772	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1773	  can lead to all sorts of problems, so it's good to say Y here.
1774
1775	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1776	  just add about 9 KB to your kernel.
1777
1778	  See <file:Documentation/x86/mtrr.txt> for more information.
1779
1780config MTRR_SANITIZER
1781	def_bool y
1782	prompt "MTRR cleanup support"
1783	depends on MTRR
1784	---help---
1785	  Convert MTRR layout from continuous to discrete, so X drivers can
1786	  add writeback entries.
1787
1788	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1789	  The largest mtrr entry size for a continuous block can be set with
1790	  mtrr_chunk_size.
1791
1792	  If unsure, say Y.
1793
1794config MTRR_SANITIZER_ENABLE_DEFAULT
1795	int "MTRR cleanup enable value (0-1)"
1796	range 0 1
1797	default "0"
1798	depends on MTRR_SANITIZER
1799	---help---
1800	  Enable mtrr cleanup default value
1801
1802config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1803	int "MTRR cleanup spare reg num (0-7)"
1804	range 0 7
1805	default "1"
1806	depends on MTRR_SANITIZER
1807	---help---
1808	  mtrr cleanup spare entries default, it can be changed via
1809	  mtrr_spare_reg_nr=N on the kernel command line.
1810
1811config X86_PAT
1812	def_bool y
1813	prompt "x86 PAT support" if EXPERT
1814	depends on MTRR
1815	---help---
1816	  Use PAT attributes to setup page level cache control.
1817
1818	  PATs are the modern equivalents of MTRRs and are much more
1819	  flexible than MTRRs.
1820
1821	  Say N here if you see bootup problems (boot crash, boot hang,
1822	  spontaneous reboots) or a non-working video driver.
1823
1824	  If unsure, say Y.
1825
1826config ARCH_USES_PG_UNCACHED
1827	def_bool y
1828	depends on X86_PAT
1829
1830config ARCH_RANDOM
1831	def_bool y
1832	prompt "x86 architectural random number generator" if EXPERT
1833	---help---
1834	  Enable the x86 architectural RDRAND instruction
1835	  (Intel Bull Mountain technology) to generate random numbers.
1836	  If supported, this is a high bandwidth, cryptographically
1837	  secure hardware random number generator.
1838
1839config X86_SMAP
1840	def_bool y
1841	prompt "Supervisor Mode Access Prevention" if EXPERT
1842	---help---
1843	  Supervisor Mode Access Prevention (SMAP) is a security
1844	  feature in newer Intel processors.  There is a small
1845	  performance cost if this enabled and turned on; there is
1846	  also a small increase in the kernel size if this is enabled.
1847
1848	  If unsure, say Y.
1849
1850config X86_INTEL_UMIP
1851	def_bool y
1852	depends on CPU_SUP_INTEL
1853	prompt "Intel User Mode Instruction Prevention" if EXPERT
1854	---help---
1855	  The User Mode Instruction Prevention (UMIP) is a security
1856	  feature in newer Intel processors. If enabled, a general
1857	  protection fault is issued if the SGDT, SLDT, SIDT, SMSW
1858	  or STR instructions are executed in user mode. These instructions
1859	  unnecessarily expose information about the hardware state.
1860
1861	  The vast majority of applications do not use these instructions.
1862	  For the very few that do, software emulation is provided in
1863	  specific cases in protected and virtual-8086 modes. Emulated
1864	  results are dummy.
1865
1866config X86_INTEL_MPX
1867	prompt "Intel MPX (Memory Protection Extensions)"
1868	def_bool n
1869	# Note: only available in 64-bit mode due to VMA flags shortage
1870	depends on CPU_SUP_INTEL && X86_64
1871	select ARCH_USES_HIGH_VMA_FLAGS
1872	---help---
1873	  MPX provides hardware features that can be used in
1874	  conjunction with compiler-instrumented code to check
1875	  memory references.  It is designed to detect buffer
1876	  overflow or underflow bugs.
1877
1878	  This option enables running applications which are
1879	  instrumented or otherwise use MPX.  It does not use MPX
1880	  itself inside the kernel or to protect the kernel
1881	  against bad memory references.
1882
1883	  Enabling this option will make the kernel larger:
1884	  ~8k of kernel text and 36 bytes of data on a 64-bit
1885	  defconfig.  It adds a long to the 'mm_struct' which
1886	  will increase the kernel memory overhead of each
1887	  process and adds some branches to paths used during
1888	  exec() and munmap().
1889
1890	  For details, see Documentation/x86/intel_mpx.txt
1891
1892	  If unsure, say N.
1893
1894config X86_INTEL_MEMORY_PROTECTION_KEYS
1895	prompt "Intel Memory Protection Keys"
1896	def_bool y
1897	# Note: only available in 64-bit mode
1898	depends on CPU_SUP_INTEL && X86_64
1899	select ARCH_USES_HIGH_VMA_FLAGS
1900	select ARCH_HAS_PKEYS
1901	---help---
1902	  Memory Protection Keys provides a mechanism for enforcing
1903	  page-based protections, but without requiring modification of the
1904	  page tables when an application changes protection domains.
1905
1906	  For details, see Documentation/x86/protection-keys.txt
1907
1908	  If unsure, say y.
1909
1910config EFI
1911	bool "EFI runtime service support"
1912	depends on ACPI
1913	select UCS2_STRING
1914	select EFI_RUNTIME_WRAPPERS
1915	---help---
1916	  This enables the kernel to use EFI runtime services that are
1917	  available (such as the EFI variable services).
1918
1919	  This option is only useful on systems that have EFI firmware.
1920	  In addition, you should use the latest ELILO loader available
1921	  at <http://elilo.sourceforge.net> in order to take advantage
1922	  of EFI runtime services. However, even with this option, the
1923	  resultant kernel should continue to boot on existing non-EFI
1924	  platforms.
1925
1926config EFI_STUB
1927       bool "EFI stub support"
1928       depends on EFI && !X86_USE_3DNOW
1929       select RELOCATABLE
1930       ---help---
1931          This kernel feature allows a bzImage to be loaded directly
1932	  by EFI firmware without the use of a bootloader.
1933
1934	  See Documentation/efi-stub.txt for more information.
1935
1936config EFI_MIXED
1937	bool "EFI mixed-mode support"
1938	depends on EFI_STUB && X86_64
1939	---help---
1940	   Enabling this feature allows a 64-bit kernel to be booted
1941	   on a 32-bit firmware, provided that your CPU supports 64-bit
1942	   mode.
1943
1944	   Note that it is not possible to boot a mixed-mode enabled
1945	   kernel via the EFI boot stub - a bootloader that supports
1946	   the EFI handover protocol must be used.
1947
1948	   If unsure, say N.
1949
1950config SECCOMP
1951	def_bool y
1952	prompt "Enable seccomp to safely compute untrusted bytecode"
1953	---help---
1954	  This kernel feature is useful for number crunching applications
1955	  that may need to compute untrusted bytecode during their
1956	  execution. By using pipes or other transports made available to
1957	  the process as file descriptors supporting the read/write
1958	  syscalls, it's possible to isolate those applications in
1959	  their own address space using seccomp. Once seccomp is
1960	  enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1961	  and the task is only allowed to execute a few safe syscalls
1962	  defined by each seccomp mode.
1963
1964	  If unsure, say Y. Only embedded should say N here.
1965
1966source "kernel/Kconfig.hz"
1967
1968config KEXEC
1969	bool "kexec system call"
1970	select KEXEC_CORE
1971	---help---
1972	  kexec is a system call that implements the ability to shutdown your
1973	  current kernel, and to start another kernel.  It is like a reboot
1974	  but it is independent of the system firmware.   And like a reboot
1975	  you can start any kernel with it, not just Linux.
1976
1977	  The name comes from the similarity to the exec system call.
1978
1979	  It is an ongoing process to be certain the hardware in a machine
1980	  is properly shutdown, so do not be surprised if this code does not
1981	  initially work for you.  As of this writing the exact hardware
1982	  interface is strongly in flux, so no good recommendation can be
1983	  made.
1984
1985config KEXEC_FILE
1986	bool "kexec file based system call"
1987	select KEXEC_CORE
1988	select BUILD_BIN2C
1989	depends on X86_64
1990	depends on CRYPTO=y
1991	depends on CRYPTO_SHA256=y
1992	---help---
1993	  This is new version of kexec system call. This system call is
1994	  file based and takes file descriptors as system call argument
1995	  for kernel and initramfs as opposed to list of segments as
1996	  accepted by previous system call.
1997
1998config ARCH_HAS_KEXEC_PURGATORY
1999	def_bool KEXEC_FILE
2000
2001config KEXEC_VERIFY_SIG
2002	bool "Verify kernel signature during kexec_file_load() syscall"
2003	depends on KEXEC_FILE
2004	---help---
2005	  This option makes kernel signature verification mandatory for
2006	  the kexec_file_load() syscall.
2007
2008	  In addition to that option, you need to enable signature
2009	  verification for the corresponding kernel image type being
2010	  loaded in order for this to work.
2011
2012config KEXEC_BZIMAGE_VERIFY_SIG
2013	bool "Enable bzImage signature verification support"
2014	depends on KEXEC_VERIFY_SIG
2015	depends on SIGNED_PE_FILE_VERIFICATION
2016	select SYSTEM_TRUSTED_KEYRING
2017	---help---
2018	  Enable bzImage signature verification support.
2019
2020config CRASH_DUMP
2021	bool "kernel crash dumps"
2022	depends on X86_64 || (X86_32 && HIGHMEM)
2023	---help---
2024	  Generate crash dump after being started by kexec.
2025	  This should be normally only set in special crash dump kernels
2026	  which are loaded in the main kernel with kexec-tools into
2027	  a specially reserved region and then later executed after
2028	  a crash by kdump/kexec. The crash dump kernel must be compiled
2029	  to a memory address not used by the main kernel or BIOS using
2030	  PHYSICAL_START, or it must be built as a relocatable image
2031	  (CONFIG_RELOCATABLE=y).
2032	  For more details see Documentation/kdump/kdump.txt
2033
2034config KEXEC_JUMP
2035	bool "kexec jump"
2036	depends on KEXEC && HIBERNATION
2037	---help---
2038	  Jump between original kernel and kexeced kernel and invoke
2039	  code in physical address mode via KEXEC
2040
2041config PHYSICAL_START
2042	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2043	default "0x1000000"
2044	---help---
2045	  This gives the physical address where the kernel is loaded.
2046
2047	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2048	  bzImage will decompress itself to above physical address and
2049	  run from there. Otherwise, bzImage will run from the address where
2050	  it has been loaded by the boot loader and will ignore above physical
2051	  address.
2052
2053	  In normal kdump cases one does not have to set/change this option
2054	  as now bzImage can be compiled as a completely relocatable image
2055	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2056	  address. This option is mainly useful for the folks who don't want
2057	  to use a bzImage for capturing the crash dump and want to use a
2058	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2059	  to be specifically compiled to run from a specific memory area
2060	  (normally a reserved region) and this option comes handy.
2061
2062	  So if you are using bzImage for capturing the crash dump,
2063	  leave the value here unchanged to 0x1000000 and set
2064	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2065	  for capturing the crash dump change this value to start of
2066	  the reserved region.  In other words, it can be set based on
2067	  the "X" value as specified in the "crashkernel=YM@XM"
2068	  command line boot parameter passed to the panic-ed
2069	  kernel. Please take a look at Documentation/kdump/kdump.txt
2070	  for more details about crash dumps.
2071
2072	  Usage of bzImage for capturing the crash dump is recommended as
2073	  one does not have to build two kernels. Same kernel can be used
2074	  as production kernel and capture kernel. Above option should have
2075	  gone away after relocatable bzImage support is introduced. But it
2076	  is present because there are users out there who continue to use
2077	  vmlinux for dump capture. This option should go away down the
2078	  line.
2079
2080	  Don't change this unless you know what you are doing.
2081
2082config RELOCATABLE
2083	bool "Build a relocatable kernel"
2084	default y
2085	---help---
2086	  This builds a kernel image that retains relocation information
2087	  so it can be loaded someplace besides the default 1MB.
2088	  The relocations tend to make the kernel binary about 10% larger,
2089	  but are discarded at runtime.
2090
2091	  One use is for the kexec on panic case where the recovery kernel
2092	  must live at a different physical address than the primary
2093	  kernel.
2094
2095	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2096	  it has been loaded at and the compile time physical address
2097	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2098
2099config RANDOMIZE_BASE
2100	bool "Randomize the address of the kernel image (KASLR)"
2101	depends on RELOCATABLE
2102	default y
2103	---help---
2104	  In support of Kernel Address Space Layout Randomization (KASLR),
2105	  this randomizes the physical address at which the kernel image
2106	  is decompressed and the virtual address where the kernel
2107	  image is mapped, as a security feature that deters exploit
2108	  attempts relying on knowledge of the location of kernel
2109	  code internals.
2110
2111	  On 64-bit, the kernel physical and virtual addresses are
2112	  randomized separately. The physical address will be anywhere
2113	  between 16MB and the top of physical memory (up to 64TB). The
2114	  virtual address will be randomized from 16MB up to 1GB (9 bits
2115	  of entropy). Note that this also reduces the memory space
2116	  available to kernel modules from 1.5GB to 1GB.
2117
2118	  On 32-bit, the kernel physical and virtual addresses are
2119	  randomized together. They will be randomized from 16MB up to
2120	  512MB (8 bits of entropy).
2121
2122	  Entropy is generated using the RDRAND instruction if it is
2123	  supported. If RDTSC is supported, its value is mixed into
2124	  the entropy pool as well. If neither RDRAND nor RDTSC are
2125	  supported, then entropy is read from the i8254 timer. The
2126	  usable entropy is limited by the kernel being built using
2127	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2128	  minimum of 2MB. As a result, only 10 bits of entropy are
2129	  theoretically possible, but the implementations are further
2130	  limited due to memory layouts.
2131
2132	  If unsure, say Y.
2133
2134# Relocation on x86 needs some additional build support
2135config X86_NEED_RELOCS
2136	def_bool y
2137	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2138
2139config PHYSICAL_ALIGN
2140	hex "Alignment value to which kernel should be aligned"
2141	default "0x200000"
2142	range 0x2000 0x1000000 if X86_32
2143	range 0x200000 0x1000000 if X86_64
2144	---help---
2145	  This value puts the alignment restrictions on physical address
2146	  where kernel is loaded and run from. Kernel is compiled for an
2147	  address which meets above alignment restriction.
2148
2149	  If bootloader loads the kernel at a non-aligned address and
2150	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2151	  address aligned to above value and run from there.
2152
2153	  If bootloader loads the kernel at a non-aligned address and
2154	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2155	  load address and decompress itself to the address it has been
2156	  compiled for and run from there. The address for which kernel is
2157	  compiled already meets above alignment restrictions. Hence the
2158	  end result is that kernel runs from a physical address meeting
2159	  above alignment restrictions.
2160
2161	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2162	  this value must be a multiple of 0x200000.
2163
2164	  Don't change this unless you know what you are doing.
2165
2166config DYNAMIC_MEMORY_LAYOUT
2167	bool
2168	---help---
2169	  This option makes base addresses of vmalloc and vmemmap as well as
2170	  __PAGE_OFFSET movable during boot.
2171
2172config RANDOMIZE_MEMORY
2173	bool "Randomize the kernel memory sections"
2174	depends on X86_64
2175	depends on RANDOMIZE_BASE
2176	select DYNAMIC_MEMORY_LAYOUT
2177	default RANDOMIZE_BASE
2178	---help---
2179	   Randomizes the base virtual address of kernel memory sections
2180	   (physical memory mapping, vmalloc & vmemmap). This security feature
2181	   makes exploits relying on predictable memory locations less reliable.
2182
2183	   The order of allocations remains unchanged. Entropy is generated in
2184	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2185	   configuration have in average 30,000 different possible virtual
2186	   addresses for each memory section.
2187
2188	   If unsure, say Y.
2189
2190config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2191	hex "Physical memory mapping padding" if EXPERT
2192	depends on RANDOMIZE_MEMORY
2193	default "0xa" if MEMORY_HOTPLUG
2194	default "0x0"
2195	range 0x1 0x40 if MEMORY_HOTPLUG
2196	range 0x0 0x40
2197	---help---
2198	   Define the padding in terabytes added to the existing physical
2199	   memory size during kernel memory randomization. It is useful
2200	   for memory hotplug support but reduces the entropy available for
2201	   address randomization.
2202
2203	   If unsure, leave at the default value.
2204
2205config HOTPLUG_CPU
2206	def_bool y
2207	depends on SMP
2208
2209config BOOTPARAM_HOTPLUG_CPU0
2210	bool "Set default setting of cpu0_hotpluggable"
2211	depends on HOTPLUG_CPU
2212	---help---
2213	  Set whether default state of cpu0_hotpluggable is on or off.
2214
2215	  Say Y here to enable CPU0 hotplug by default. If this switch
2216	  is turned on, there is no need to give cpu0_hotplug kernel
2217	  parameter and the CPU0 hotplug feature is enabled by default.
2218
2219	  Please note: there are two known CPU0 dependencies if you want
2220	  to enable the CPU0 hotplug feature either by this switch or by
2221	  cpu0_hotplug kernel parameter.
2222
2223	  First, resume from hibernate or suspend always starts from CPU0.
2224	  So hibernate and suspend are prevented if CPU0 is offline.
2225
2226	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2227	  offline if any interrupt can not migrate out of CPU0. There may
2228	  be other CPU0 dependencies.
2229
2230	  Please make sure the dependencies are under your control before
2231	  you enable this feature.
2232
2233	  Say N if you don't want to enable CPU0 hotplug feature by default.
2234	  You still can enable the CPU0 hotplug feature at boot by kernel
2235	  parameter cpu0_hotplug.
2236
2237config DEBUG_HOTPLUG_CPU0
2238	def_bool n
2239	prompt "Debug CPU0 hotplug"
2240	depends on HOTPLUG_CPU
2241	---help---
2242	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2243	  soon as possible and boots up userspace with CPU0 offlined. User
2244	  can online CPU0 back after boot time.
2245
2246	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2247	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2248	  compilation or giving cpu0_hotplug kernel parameter at boot.
2249
2250	  If unsure, say N.
2251
2252config COMPAT_VDSO
2253	def_bool n
2254	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2255	depends on COMPAT_32
2256	---help---
2257	  Certain buggy versions of glibc will crash if they are
2258	  presented with a 32-bit vDSO that is not mapped at the address
2259	  indicated in its segment table.
2260
2261	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2262	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2263	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2264	  the only released version with the bug, but OpenSUSE 9
2265	  contains a buggy "glibc 2.3.2".
2266
2267	  The symptom of the bug is that everything crashes on startup, saying:
2268	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2269
2270	  Saying Y here changes the default value of the vdso32 boot
2271	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2272	  This works around the glibc bug but hurts performance.
2273
2274	  If unsure, say N: if you are compiling your own kernel, you
2275	  are unlikely to be using a buggy version of glibc.
2276
2277choice
2278	prompt "vsyscall table for legacy applications"
2279	depends on X86_64
2280	default LEGACY_VSYSCALL_EMULATE
2281	help
2282	  Legacy user code that does not know how to find the vDSO expects
2283	  to be able to issue three syscalls by calling fixed addresses in
2284	  kernel space. Since this location is not randomized with ASLR,
2285	  it can be used to assist security vulnerability exploitation.
2286
2287	  This setting can be changed at boot time via the kernel command
2288	  line parameter vsyscall=[emulate|none].
2289
2290	  On a system with recent enough glibc (2.14 or newer) and no
2291	  static binaries, you can say None without a performance penalty
2292	  to improve security.
2293
2294	  If unsure, select "Emulate".
2295
2296	config LEGACY_VSYSCALL_EMULATE
2297		bool "Emulate"
2298		help
2299		  The kernel traps and emulates calls into the fixed
2300		  vsyscall address mapping. This makes the mapping
2301		  non-executable, but it still contains known contents,
2302		  which could be used in certain rare security vulnerability
2303		  exploits. This configuration is recommended when userspace
2304		  still uses the vsyscall area.
2305
2306	config LEGACY_VSYSCALL_NONE
2307		bool "None"
2308		help
2309		  There will be no vsyscall mapping at all. This will
2310		  eliminate any risk of ASLR bypass due to the vsyscall
2311		  fixed address mapping. Attempts to use the vsyscalls
2312		  will be reported to dmesg, so that either old or
2313		  malicious userspace programs can be identified.
2314
2315endchoice
2316
2317config CMDLINE_BOOL
2318	bool "Built-in kernel command line"
2319	---help---
2320	  Allow for specifying boot arguments to the kernel at
2321	  build time.  On some systems (e.g. embedded ones), it is
2322	  necessary or convenient to provide some or all of the
2323	  kernel boot arguments with the kernel itself (that is,
2324	  to not rely on the boot loader to provide them.)
2325
2326	  To compile command line arguments into the kernel,
2327	  set this option to 'Y', then fill in the
2328	  boot arguments in CONFIG_CMDLINE.
2329
2330	  Systems with fully functional boot loaders (i.e. non-embedded)
2331	  should leave this option set to 'N'.
2332
2333config CMDLINE
2334	string "Built-in kernel command string"
2335	depends on CMDLINE_BOOL
2336	default ""
2337	---help---
2338	  Enter arguments here that should be compiled into the kernel
2339	  image and used at boot time.  If the boot loader provides a
2340	  command line at boot time, it is appended to this string to
2341	  form the full kernel command line, when the system boots.
2342
2343	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2344	  change this behavior.
2345
2346	  In most cases, the command line (whether built-in or provided
2347	  by the boot loader) should specify the device for the root
2348	  file system.
2349
2350config CMDLINE_OVERRIDE
2351	bool "Built-in command line overrides boot loader arguments"
2352	depends on CMDLINE_BOOL
2353	---help---
2354	  Set this option to 'Y' to have the kernel ignore the boot loader
2355	  command line, and use ONLY the built-in command line.
2356
2357	  This is used to work around broken boot loaders.  This should
2358	  be set to 'N' under normal conditions.
2359
2360config MODIFY_LDT_SYSCALL
2361	bool "Enable the LDT (local descriptor table)" if EXPERT
2362	default y
2363	---help---
2364	  Linux can allow user programs to install a per-process x86
2365	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2366	  call.  This is required to run 16-bit or segmented code such as
2367	  DOSEMU or some Wine programs.  It is also used by some very old
2368	  threading libraries.
2369
2370	  Enabling this feature adds a small amount of overhead to
2371	  context switches and increases the low-level kernel attack
2372	  surface.  Disabling it removes the modify_ldt(2) system call.
2373
2374	  Saying 'N' here may make sense for embedded or server kernels.
2375
2376source "kernel/livepatch/Kconfig"
2377
2378endmenu
2379
2380config ARCH_HAS_ADD_PAGES
2381	def_bool y
2382	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2383
2384config ARCH_ENABLE_MEMORY_HOTPLUG
2385	def_bool y
2386	depends on X86_64 || (X86_32 && HIGHMEM)
2387
2388config ARCH_ENABLE_MEMORY_HOTREMOVE
2389	def_bool y
2390	depends on MEMORY_HOTPLUG
2391
2392config USE_PERCPU_NUMA_NODE_ID
2393	def_bool y
2394	depends on NUMA
2395
2396config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2397	def_bool y
2398	depends on X86_64 || X86_PAE
2399
2400config ARCH_ENABLE_HUGEPAGE_MIGRATION
2401	def_bool y
2402	depends on X86_64 && HUGETLB_PAGE && MIGRATION
2403
2404config ARCH_ENABLE_THP_MIGRATION
2405	def_bool y
2406	depends on X86_64 && TRANSPARENT_HUGEPAGE
2407
2408menu "Power management and ACPI options"
2409
2410config ARCH_HIBERNATION_HEADER
2411	def_bool y
2412	depends on HIBERNATION
2413
2414source "kernel/power/Kconfig"
2415
2416source "drivers/acpi/Kconfig"
2417
2418source "drivers/sfi/Kconfig"
2419
2420config X86_APM_BOOT
2421	def_bool y
2422	depends on APM
2423
2424menuconfig APM
2425	tristate "APM (Advanced Power Management) BIOS support"
2426	depends on X86_32 && PM_SLEEP
2427	---help---
2428	  APM is a BIOS specification for saving power using several different
2429	  techniques. This is mostly useful for battery powered laptops with
2430	  APM compliant BIOSes. If you say Y here, the system time will be
2431	  reset after a RESUME operation, the /proc/apm device will provide
2432	  battery status information, and user-space programs will receive
2433	  notification of APM "events" (e.g. battery status change).
2434
2435	  If you select "Y" here, you can disable actual use of the APM
2436	  BIOS by passing the "apm=off" option to the kernel at boot time.
2437
2438	  Note that the APM support is almost completely disabled for
2439	  machines with more than one CPU.
2440
2441	  In order to use APM, you will need supporting software. For location
2442	  and more information, read <file:Documentation/power/apm-acpi.txt>
2443	  and the Battery Powered Linux mini-HOWTO, available from
2444	  <http://www.tldp.org/docs.html#howto>.
2445
2446	  This driver does not spin down disk drives (see the hdparm(8)
2447	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2448	  VESA-compliant "green" monitors.
2449
2450	  This driver does not support the TI 4000M TravelMate and the ACER
2451	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2452	  desktop machines also don't have compliant BIOSes, and this driver
2453	  may cause those machines to panic during the boot phase.
2454
2455	  Generally, if you don't have a battery in your machine, there isn't
2456	  much point in using this driver and you should say N. If you get
2457	  random kernel OOPSes or reboots that don't seem to be related to
2458	  anything, try disabling/enabling this option (or disabling/enabling
2459	  APM in your BIOS).
2460
2461	  Some other things you should try when experiencing seemingly random,
2462	  "weird" problems:
2463
2464	  1) make sure that you have enough swap space and that it is
2465	  enabled.
2466	  2) pass the "no-hlt" option to the kernel
2467	  3) switch on floating point emulation in the kernel and pass
2468	  the "no387" option to the kernel
2469	  4) pass the "floppy=nodma" option to the kernel
2470	  5) pass the "mem=4M" option to the kernel (thereby disabling
2471	  all but the first 4 MB of RAM)
2472	  6) make sure that the CPU is not over clocked.
2473	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2474	  8) disable the cache from your BIOS settings
2475	  9) install a fan for the video card or exchange video RAM
2476	  10) install a better fan for the CPU
2477	  11) exchange RAM chips
2478	  12) exchange the motherboard.
2479
2480	  To compile this driver as a module, choose M here: the
2481	  module will be called apm.
2482
2483if APM
2484
2485config APM_IGNORE_USER_SUSPEND
2486	bool "Ignore USER SUSPEND"
2487	---help---
2488	  This option will ignore USER SUSPEND requests. On machines with a
2489	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2490	  series notebooks, it is necessary to say Y because of a BIOS bug.
2491
2492config APM_DO_ENABLE
2493	bool "Enable PM at boot time"
2494	---help---
2495	  Enable APM features at boot time. From page 36 of the APM BIOS
2496	  specification: "When disabled, the APM BIOS does not automatically
2497	  power manage devices, enter the Standby State, enter the Suspend
2498	  State, or take power saving steps in response to CPU Idle calls."
2499	  This driver will make CPU Idle calls when Linux is idle (unless this
2500	  feature is turned off -- see "Do CPU IDLE calls", below). This
2501	  should always save battery power, but more complicated APM features
2502	  will be dependent on your BIOS implementation. You may need to turn
2503	  this option off if your computer hangs at boot time when using APM
2504	  support, or if it beeps continuously instead of suspending. Turn
2505	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2506	  T400CDT. This is off by default since most machines do fine without
2507	  this feature.
2508
2509config APM_CPU_IDLE
2510	depends on CPU_IDLE
2511	bool "Make CPU Idle calls when idle"
2512	---help---
2513	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2514	  On some machines, this can activate improved power savings, such as
2515	  a slowed CPU clock rate, when the machine is idle. These idle calls
2516	  are made after the idle loop has run for some length of time (e.g.,
2517	  333 mS). On some machines, this will cause a hang at boot time or
2518	  whenever the CPU becomes idle. (On machines with more than one CPU,
2519	  this option does nothing.)
2520
2521config APM_DISPLAY_BLANK
2522	bool "Enable console blanking using APM"
2523	---help---
2524	  Enable console blanking using the APM. Some laptops can use this to
2525	  turn off the LCD backlight when the screen blanker of the Linux
2526	  virtual console blanks the screen. Note that this is only used by
2527	  the virtual console screen blanker, and won't turn off the backlight
2528	  when using the X Window system. This also doesn't have anything to
2529	  do with your VESA-compliant power-saving monitor. Further, this
2530	  option doesn't work for all laptops -- it might not turn off your
2531	  backlight at all, or it might print a lot of errors to the console,
2532	  especially if you are using gpm.
2533
2534config APM_ALLOW_INTS
2535	bool "Allow interrupts during APM BIOS calls"
2536	---help---
2537	  Normally we disable external interrupts while we are making calls to
2538	  the APM BIOS as a measure to lessen the effects of a badly behaving
2539	  BIOS implementation.  The BIOS should reenable interrupts if it
2540	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2541	  many of the newer IBM Thinkpads.  If you experience hangs when you
2542	  suspend, try setting this to Y.  Otherwise, say N.
2543
2544endif # APM
2545
2546source "drivers/cpufreq/Kconfig"
2547
2548source "drivers/cpuidle/Kconfig"
2549
2550source "drivers/idle/Kconfig"
2551
2552endmenu
2553
2554
2555menu "Bus options (PCI etc.)"
2556
2557choice
2558	prompt "PCI access mode"
2559	depends on X86_32 && PCI
2560	default PCI_GOANY
2561	---help---
2562	  On PCI systems, the BIOS can be used to detect the PCI devices and
2563	  determine their configuration. However, some old PCI motherboards
2564	  have BIOS bugs and may crash if this is done. Also, some embedded
2565	  PCI-based systems don't have any BIOS at all. Linux can also try to
2566	  detect the PCI hardware directly without using the BIOS.
2567
2568	  With this option, you can specify how Linux should detect the
2569	  PCI devices. If you choose "BIOS", the BIOS will be used,
2570	  if you choose "Direct", the BIOS won't be used, and if you
2571	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2572	  If you choose "Any", the kernel will try MMCONFIG, then the
2573	  direct access method and falls back to the BIOS if that doesn't
2574	  work. If unsure, go with the default, which is "Any".
2575
2576config PCI_GOBIOS
2577	bool "BIOS"
2578
2579config PCI_GOMMCONFIG
2580	bool "MMConfig"
2581
2582config PCI_GODIRECT
2583	bool "Direct"
2584
2585config PCI_GOOLPC
2586	bool "OLPC XO-1"
2587	depends on OLPC
2588
2589config PCI_GOANY
2590	bool "Any"
2591
2592endchoice
2593
2594config PCI_BIOS
2595	def_bool y
2596	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2597
2598# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2599config PCI_DIRECT
2600	def_bool y
2601	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2602
2603config PCI_MMCONFIG
2604	bool "Support mmconfig PCI config space access" if X86_64
2605	default y
2606	depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2607	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2608
2609config PCI_OLPC
2610	def_bool y
2611	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2612
2613config PCI_XEN
2614	def_bool y
2615	depends on PCI && XEN
2616	select SWIOTLB_XEN
2617
2618config MMCONF_FAM10H
2619	def_bool y
2620	depends on X86_64 && PCI_MMCONFIG && ACPI
2621
2622config PCI_CNB20LE_QUIRK
2623	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2624	depends on PCI
2625	help
2626	  Read the PCI windows out of the CNB20LE host bridge. This allows
2627	  PCI hotplug to work on systems with the CNB20LE chipset which do
2628	  not have ACPI.
2629
2630	  There's no public spec for this chipset, and this functionality
2631	  is known to be incomplete.
2632
2633	  You should say N unless you know you need this.
2634
2635config ISA_BUS
2636	bool "ISA bus support on modern systems" if EXPERT
2637	help
2638	  Expose ISA bus device drivers and options available for selection and
2639	  configuration. Enable this option if your target machine has an ISA
2640	  bus. ISA is an older system, displaced by PCI and newer bus
2641	  architectures -- if your target machine is modern, it probably does
2642	  not have an ISA bus.
2643
2644	  If unsure, say N.
2645
2646# x86_64 have no ISA slots, but can have ISA-style DMA.
2647config ISA_DMA_API
2648	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2649	default y
2650	help
2651	  Enables ISA-style DMA support for devices requiring such controllers.
2652	  If unsure, say Y.
2653
2654if X86_32
2655
2656config ISA
2657	bool "ISA support"
2658	---help---
2659	  Find out whether you have ISA slots on your motherboard.  ISA is the
2660	  name of a bus system, i.e. the way the CPU talks to the other stuff
2661	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2662	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2663	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2664
2665config SCx200
2666	tristate "NatSemi SCx200 support"
2667	---help---
2668	  This provides basic support for National Semiconductor's
2669	  (now AMD's) Geode processors.  The driver probes for the
2670	  PCI-IDs of several on-chip devices, so its a good dependency
2671	  for other scx200_* drivers.
2672
2673	  If compiled as a module, the driver is named scx200.
2674
2675config SCx200HR_TIMER
2676	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2677	depends on SCx200
2678	default y
2679	---help---
2680	  This driver provides a clocksource built upon the on-chip
2681	  27MHz high-resolution timer.  Its also a workaround for
2682	  NSC Geode SC-1100's buggy TSC, which loses time when the
2683	  processor goes idle (as is done by the scheduler).  The
2684	  other workaround is idle=poll boot option.
2685
2686config OLPC
2687	bool "One Laptop Per Child support"
2688	depends on !X86_PAE
2689	select GPIOLIB
2690	select OF
2691	select OF_PROMTREE
2692	select IRQ_DOMAIN
2693	---help---
2694	  Add support for detecting the unique features of the OLPC
2695	  XO hardware.
2696
2697config OLPC_XO1_PM
2698	bool "OLPC XO-1 Power Management"
2699	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2700	---help---
2701	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2702
2703config OLPC_XO1_RTC
2704	bool "OLPC XO-1 Real Time Clock"
2705	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2706	---help---
2707	  Add support for the XO-1 real time clock, which can be used as a
2708	  programmable wakeup source.
2709
2710config OLPC_XO1_SCI
2711	bool "OLPC XO-1 SCI extras"
2712	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2713	depends on INPUT=y
2714	select POWER_SUPPLY
2715	---help---
2716	  Add support for SCI-based features of the OLPC XO-1 laptop:
2717	   - EC-driven system wakeups
2718	   - Power button
2719	   - Ebook switch
2720	   - Lid switch
2721	   - AC adapter status updates
2722	   - Battery status updates
2723
2724config OLPC_XO15_SCI
2725	bool "OLPC XO-1.5 SCI extras"
2726	depends on OLPC && ACPI
2727	select POWER_SUPPLY
2728	---help---
2729	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2730	   - EC-driven system wakeups
2731	   - AC adapter status updates
2732	   - Battery status updates
2733
2734config ALIX
2735	bool "PCEngines ALIX System Support (LED setup)"
2736	select GPIOLIB
2737	---help---
2738	  This option enables system support for the PCEngines ALIX.
2739	  At present this just sets up LEDs for GPIO control on
2740	  ALIX2/3/6 boards.  However, other system specific setup should
2741	  get added here.
2742
2743	  Note: You must still enable the drivers for GPIO and LED support
2744	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2745
2746	  Note: You have to set alix.force=1 for boards with Award BIOS.
2747
2748config NET5501
2749	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2750	select GPIOLIB
2751	---help---
2752	  This option enables system support for the Soekris Engineering net5501.
2753
2754config GEOS
2755	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2756	select GPIOLIB
2757	depends on DMI
2758	---help---
2759	  This option enables system support for the Traverse Technologies GEOS.
2760
2761config TS5500
2762	bool "Technologic Systems TS-5500 platform support"
2763	depends on MELAN
2764	select CHECK_SIGNATURE
2765	select NEW_LEDS
2766	select LEDS_CLASS
2767	---help---
2768	  This option enables system support for the Technologic Systems TS-5500.
2769
2770endif # X86_32
2771
2772config AMD_NB
2773	def_bool y
2774	depends on CPU_SUP_AMD && PCI
2775
2776config X86_SYSFB
2777	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2778	help
2779	  Firmwares often provide initial graphics framebuffers so the BIOS,
2780	  bootloader or kernel can show basic video-output during boot for
2781	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2782	  Extensions and EFI-framebuffers for this, which are mostly limited
2783	  to x86.
2784	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2785	  framebuffers so the new generic system-framebuffer drivers can be
2786	  used on x86. If the framebuffer is not compatible with the generic
2787	  modes, it is advertised as fallback platform framebuffer so legacy
2788	  drivers like efifb, vesafb and uvesafb can pick it up.
2789	  If this option is not selected, all system framebuffers are always
2790	  marked as fallback platform framebuffers as usual.
2791
2792	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2793	  not be able to pick up generic system framebuffers if this option
2794	  is selected. You are highly encouraged to enable simplefb as
2795	  replacement if you select this option. simplefb can correctly deal
2796	  with generic system framebuffers. But you should still keep vesafb
2797	  and others enabled as fallback if a system framebuffer is
2798	  incompatible with simplefb.
2799
2800	  If unsure, say Y.
2801
2802endmenu
2803
2804
2805menu "Binary Emulations"
2806
2807config IA32_EMULATION
2808	bool "IA32 Emulation"
2809	depends on X86_64
2810	select ARCH_WANT_OLD_COMPAT_IPC
2811	select BINFMT_ELF
2812	select COMPAT_BINFMT_ELF
2813	select COMPAT_OLD_SIGACTION
2814	---help---
2815	  Include code to run legacy 32-bit programs under a
2816	  64-bit kernel. You should likely turn this on, unless you're
2817	  100% sure that you don't have any 32-bit programs left.
2818
2819config IA32_AOUT
2820	tristate "IA32 a.out support"
2821	depends on IA32_EMULATION
2822	depends on BROKEN
2823	---help---
2824	  Support old a.out binaries in the 32bit emulation.
2825
2826config X86_X32
2827	bool "x32 ABI for 64-bit mode"
2828	depends on X86_64
2829	---help---
2830	  Include code to run binaries for the x32 native 32-bit ABI
2831	  for 64-bit processors.  An x32 process gets access to the
2832	  full 64-bit register file and wide data path while leaving
2833	  pointers at 32 bits for smaller memory footprint.
2834
2835	  You will need a recent binutils (2.22 or later) with
2836	  elf32_x86_64 support enabled to compile a kernel with this
2837	  option set.
2838
2839config COMPAT_32
2840	def_bool y
2841	depends on IA32_EMULATION || X86_32
2842	select HAVE_UID16
2843	select OLD_SIGSUSPEND3
2844
2845config COMPAT
2846	def_bool y
2847	depends on IA32_EMULATION || X86_X32
2848
2849if COMPAT
2850config COMPAT_FOR_U64_ALIGNMENT
2851	def_bool y
2852
2853config SYSVIPC_COMPAT
2854	def_bool y
2855	depends on SYSVIPC
2856endif
2857
2858endmenu
2859
2860
2861config HAVE_ATOMIC_IOMAP
2862	def_bool y
2863	depends on X86_32
2864
2865config X86_DEV_DMA_OPS
2866	bool
2867
2868config HAVE_GENERIC_GUP
2869	def_bool y
2870
2871source "drivers/firmware/Kconfig"
2872
2873source "arch/x86/kvm/Kconfig"
2874