xref: /linux/arch/x86/Kconfig (revision 0774a6ed294b963dc76df2d8342ab86d030759ec)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select HAVE_DEBUG_STACKOVERFLOW
18	select MODULES_USE_ELF_REL
19	select OLD_SIGACTION
20	select GENERIC_VDSO_32
21
22config X86_64
23	def_bool y
24	depends on 64BIT
25	# Options that are inherently 64-bit kernel only:
26	select ARCH_HAS_GIGANTIC_PAGE
27	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
28	select ARCH_USE_CMPXCHG_LOCKREF
29	select HAVE_ARCH_SOFT_DIRTY
30	select MODULES_USE_ELF_RELA
31	select NEED_DMA_MAP_STATE
32	select SWIOTLB
33
34config FORCE_DYNAMIC_FTRACE
35	def_bool y
36	depends on X86_32
37	depends on FUNCTION_TRACER
38	select DYNAMIC_FTRACE
39	help
40	 We keep the static function tracing (!DYNAMIC_FTRACE) around
41	 in order to test the non static function tracing in the
42	 generic code, as other architectures still use it. But we
43	 only need to keep it around for x86_64. No need to keep it
44	 for x86_32. For x86_32, force DYNAMIC_FTRACE.
45#
46# Arch settings
47#
48# ( Note that options that are marked 'if X86_64' could in principle be
49#   ported to 32-bit as well. )
50#
51config X86
52	def_bool y
53	#
54	# Note: keep this list sorted alphabetically
55	#
56	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
57	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
58	select ARCH_32BIT_OFF_T			if X86_32
59	select ARCH_CLOCKSOURCE_INIT
60	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
61	select ARCH_HAS_DEBUG_VIRTUAL
62	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
63	select ARCH_HAS_DEVMEM_IS_ALLOWED
64	select ARCH_HAS_EARLY_DEBUG		if KGDB
65	select ARCH_HAS_ELF_RANDOMIZE
66	select ARCH_HAS_FAST_MULTIPLIER
67	select ARCH_HAS_FILTER_PGPROT
68	select ARCH_HAS_FORTIFY_SOURCE
69	select ARCH_HAS_GCOV_PROFILE_ALL
70	select ARCH_HAS_KCOV			if X86_64 && STACK_VALIDATION
71	select ARCH_HAS_MEM_ENCRYPT
72	select ARCH_HAS_MEMBARRIER_SYNC_CORE
73	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
74	select ARCH_HAS_PMEM_API		if X86_64
75	select ARCH_HAS_PTE_DEVMAP		if X86_64
76	select ARCH_HAS_PTE_SPECIAL
77	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
78	select ARCH_HAS_COPY_MC			if X86_64
79	select ARCH_HAS_SET_MEMORY
80	select ARCH_HAS_SET_DIRECT_MAP
81	select ARCH_HAS_STRICT_KERNEL_RWX
82	select ARCH_HAS_STRICT_MODULE_RWX
83	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
84	select ARCH_HAS_SYSCALL_WRAPPER
85	select ARCH_HAS_UBSAN_SANITIZE_ALL
86	select ARCH_HAS_DEBUG_WX
87	select ARCH_HAVE_NMI_SAFE_CMPXCHG
88	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
89	select ARCH_MIGHT_HAVE_PC_PARPORT
90	select ARCH_MIGHT_HAVE_PC_SERIO
91	select ARCH_STACKWALK
92	select ARCH_SUPPORTS_ACPI
93	select ARCH_SUPPORTS_ATOMIC_RMW
94	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
95	select ARCH_USE_BUILTIN_BSWAP
96	select ARCH_USE_QUEUED_RWLOCKS
97	select ARCH_USE_QUEUED_SPINLOCKS
98	select ARCH_USE_SYM_ANNOTATIONS
99	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
100	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
101	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
102	select ARCH_WANT_HUGE_PMD_SHARE
103	select ARCH_WANTS_THP_SWAP		if X86_64
104	select BUILDTIME_TABLE_SORT
105	select CLKEVT_I8253
106	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
107	select CLOCKSOURCE_WATCHDOG
108	select DCACHE_WORD_ACCESS
109	select EDAC_ATOMIC_SCRUB
110	select EDAC_SUPPORT
111	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
112	select GENERIC_CLOCKEVENTS_MIN_ADJUST
113	select GENERIC_CMOS_UPDATE
114	select GENERIC_CPU_AUTOPROBE
115	select GENERIC_CPU_VULNERABILITIES
116	select GENERIC_EARLY_IOREMAP
117	select GENERIC_ENTRY
118	select GENERIC_FIND_FIRST_BIT
119	select GENERIC_IOMAP
120	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
121	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
122	select GENERIC_IRQ_MIGRATION		if SMP
123	select GENERIC_IRQ_PROBE
124	select GENERIC_IRQ_RESERVATION_MODE
125	select GENERIC_IRQ_SHOW
126	select GENERIC_PENDING_IRQ		if SMP
127	select GENERIC_PTDUMP
128	select GENERIC_SMP_IDLE_THREAD
129	select GENERIC_STRNCPY_FROM_USER
130	select GENERIC_STRNLEN_USER
131	select GENERIC_TIME_VSYSCALL
132	select GENERIC_GETTIMEOFDAY
133	select GENERIC_VDSO_TIME_NS
134	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
135	select HARDIRQS_SW_RESEND
136	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
137	select HAVE_ACPI_APEI			if ACPI
138	select HAVE_ACPI_APEI_NMI		if ACPI
139	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
140	select HAVE_ARCH_AUDITSYSCALL
141	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
142	select HAVE_ARCH_JUMP_LABEL
143	select HAVE_ARCH_JUMP_LABEL_RELATIVE
144	select HAVE_ARCH_KASAN			if X86_64
145	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
146	select HAVE_ARCH_KGDB
147	select HAVE_ARCH_MMAP_RND_BITS		if MMU
148	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
149	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
150	select HAVE_ARCH_PREL32_RELOCATIONS
151	select HAVE_ARCH_SECCOMP_FILTER
152	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
153	select HAVE_ARCH_STACKLEAK
154	select HAVE_ARCH_TRACEHOOK
155	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
156	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
157	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
158	select HAVE_ARCH_VMAP_STACK		if X86_64
159	select HAVE_ARCH_WITHIN_STACK_FRAMES
160	select HAVE_ASM_MODVERSIONS
161	select HAVE_CMPXCHG_DOUBLE
162	select HAVE_CMPXCHG_LOCAL
163	select HAVE_CONTEXT_TRACKING		if X86_64
164	select HAVE_C_RECORDMCOUNT
165	select HAVE_DEBUG_KMEMLEAK
166	select HAVE_DMA_CONTIGUOUS
167	select HAVE_DYNAMIC_FTRACE
168	select HAVE_DYNAMIC_FTRACE_WITH_REGS
169	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
170	select HAVE_EBPF_JIT
171	select HAVE_EFFICIENT_UNALIGNED_ACCESS
172	select HAVE_EISA
173	select HAVE_EXIT_THREAD
174	select HAVE_FAST_GUP
175	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
176	select HAVE_FTRACE_MCOUNT_RECORD
177	select HAVE_FUNCTION_GRAPH_TRACER
178	select HAVE_FUNCTION_TRACER
179	select HAVE_GCC_PLUGINS
180	select HAVE_HW_BREAKPOINT
181	select HAVE_IDE
182	select HAVE_IOREMAP_PROT
183	select HAVE_IRQ_TIME_ACCOUNTING
184	select HAVE_KERNEL_BZIP2
185	select HAVE_KERNEL_GZIP
186	select HAVE_KERNEL_LZ4
187	select HAVE_KERNEL_LZMA
188	select HAVE_KERNEL_LZO
189	select HAVE_KERNEL_XZ
190	select HAVE_KERNEL_ZSTD
191	select HAVE_KPROBES
192	select HAVE_KPROBES_ON_FTRACE
193	select HAVE_FUNCTION_ERROR_INJECTION
194	select HAVE_KRETPROBES
195	select HAVE_KVM
196	select HAVE_LIVEPATCH			if X86_64
197	select HAVE_MIXED_BREAKPOINTS_REGS
198	select HAVE_MOD_ARCH_SPECIFIC
199	select HAVE_MOVE_PMD
200	select HAVE_NMI
201	select HAVE_OPROFILE
202	select HAVE_OPTPROBES
203	select HAVE_PCSPKR_PLATFORM
204	select HAVE_PERF_EVENTS
205	select HAVE_PERF_EVENTS_NMI
206	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
207	select HAVE_PCI
208	select HAVE_PERF_REGS
209	select HAVE_PERF_USER_STACK_DUMP
210	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
211	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
212	select HAVE_REGS_AND_STACK_ACCESS_API
213	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
214	select HAVE_FUNCTION_ARG_ACCESS_API
215	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
216	select HAVE_STACK_VALIDATION		if X86_64
217	select HAVE_STATIC_CALL
218	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
219	select HAVE_RSEQ
220	select HAVE_SYSCALL_TRACEPOINTS
221	select HAVE_UNSTABLE_SCHED_CLOCK
222	select HAVE_USER_RETURN_NOTIFIER
223	select HAVE_GENERIC_VDSO
224	select HOTPLUG_SMT			if SMP
225	select IRQ_FORCED_THREADING
226	select NEED_SG_DMA_LENGTH
227	select PCI_DOMAINS			if PCI
228	select PCI_LOCKLESS_CONFIG		if PCI
229	select PERF_EVENTS
230	select RTC_LIB
231	select RTC_MC146818_LIB
232	select SPARSE_IRQ
233	select SRCU
234	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
235	select SYSCTL_EXCEPTION_TRACE
236	select THREAD_INFO_IN_TASK
237	select USER_STACKTRACE_SUPPORT
238	select VIRT_TO_BUS
239	select HAVE_ARCH_KCSAN			if X86_64
240	select X86_FEATURE_NAMES		if PROC_FS
241	select PROC_PID_ARCH_STATUS		if PROC_FS
242	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
243
244config INSTRUCTION_DECODER
245	def_bool y
246	depends on KPROBES || PERF_EVENTS || UPROBES
247
248config OUTPUT_FORMAT
249	string
250	default "elf32-i386" if X86_32
251	default "elf64-x86-64" if X86_64
252
253config LOCKDEP_SUPPORT
254	def_bool y
255
256config STACKTRACE_SUPPORT
257	def_bool y
258
259config MMU
260	def_bool y
261
262config ARCH_MMAP_RND_BITS_MIN
263	default 28 if 64BIT
264	default 8
265
266config ARCH_MMAP_RND_BITS_MAX
267	default 32 if 64BIT
268	default 16
269
270config ARCH_MMAP_RND_COMPAT_BITS_MIN
271	default 8
272
273config ARCH_MMAP_RND_COMPAT_BITS_MAX
274	default 16
275
276config SBUS
277	bool
278
279config GENERIC_ISA_DMA
280	def_bool y
281	depends on ISA_DMA_API
282
283config GENERIC_BUG
284	def_bool y
285	depends on BUG
286	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
287
288config GENERIC_BUG_RELATIVE_POINTERS
289	bool
290
291config ARCH_MAY_HAVE_PC_FDC
292	def_bool y
293	depends on ISA_DMA_API
294
295config GENERIC_CALIBRATE_DELAY
296	def_bool y
297
298config ARCH_HAS_CPU_RELAX
299	def_bool y
300
301config ARCH_HAS_CACHE_LINE_SIZE
302	def_bool y
303
304config ARCH_HAS_FILTER_PGPROT
305	def_bool y
306
307config HAVE_SETUP_PER_CPU_AREA
308	def_bool y
309
310config NEED_PER_CPU_EMBED_FIRST_CHUNK
311	def_bool y
312
313config NEED_PER_CPU_PAGE_FIRST_CHUNK
314	def_bool y
315
316config ARCH_HIBERNATION_POSSIBLE
317	def_bool y
318
319config ARCH_SUSPEND_POSSIBLE
320	def_bool y
321
322config ARCH_WANT_GENERAL_HUGETLB
323	def_bool y
324
325config ZONE_DMA32
326	def_bool y if X86_64
327
328config AUDIT_ARCH
329	def_bool y if X86_64
330
331config ARCH_SUPPORTS_DEBUG_PAGEALLOC
332	def_bool y
333
334config KASAN_SHADOW_OFFSET
335	hex
336	depends on KASAN
337	default 0xdffffc0000000000
338
339config HAVE_INTEL_TXT
340	def_bool y
341	depends on INTEL_IOMMU && ACPI
342
343config X86_32_SMP
344	def_bool y
345	depends on X86_32 && SMP
346
347config X86_64_SMP
348	def_bool y
349	depends on X86_64 && SMP
350
351config X86_32_LAZY_GS
352	def_bool y
353	depends on X86_32 && !STACKPROTECTOR
354
355config ARCH_SUPPORTS_UPROBES
356	def_bool y
357
358config FIX_EARLYCON_MEM
359	def_bool y
360
361config DYNAMIC_PHYSICAL_MASK
362	bool
363
364config PGTABLE_LEVELS
365	int
366	default 5 if X86_5LEVEL
367	default 4 if X86_64
368	default 3 if X86_PAE
369	default 2
370
371config CC_HAS_SANE_STACKPROTECTOR
372	bool
373	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
374	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
375	help
376	   We have to make sure stack protector is unconditionally disabled if
377	   the compiler produces broken code.
378
379menu "Processor type and features"
380
381config ZONE_DMA
382	bool "DMA memory allocation support" if EXPERT
383	default y
384	help
385	  DMA memory allocation support allows devices with less than 32-bit
386	  addressing to allocate within the first 16MB of address space.
387	  Disable if no such devices will be used.
388
389	  If unsure, say Y.
390
391config SMP
392	bool "Symmetric multi-processing support"
393	help
394	  This enables support for systems with more than one CPU. If you have
395	  a system with only one CPU, say N. If you have a system with more
396	  than one CPU, say Y.
397
398	  If you say N here, the kernel will run on uni- and multiprocessor
399	  machines, but will use only one CPU of a multiprocessor machine. If
400	  you say Y here, the kernel will run on many, but not all,
401	  uniprocessor machines. On a uniprocessor machine, the kernel
402	  will run faster if you say N here.
403
404	  Note that if you say Y here and choose architecture "586" or
405	  "Pentium" under "Processor family", the kernel will not work on 486
406	  architectures. Similarly, multiprocessor kernels for the "PPro"
407	  architecture may not work on all Pentium based boards.
408
409	  People using multiprocessor machines who say Y here should also say
410	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
411	  Management" code will be disabled if you say Y here.
412
413	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
414	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
415	  <http://www.tldp.org/docs.html#howto>.
416
417	  If you don't know what to do here, say N.
418
419config X86_FEATURE_NAMES
420	bool "Processor feature human-readable names" if EMBEDDED
421	default y
422	help
423	  This option compiles in a table of x86 feature bits and corresponding
424	  names.  This is required to support /proc/cpuinfo and a few kernel
425	  messages.  You can disable this to save space, at the expense of
426	  making those few kernel messages show numeric feature bits instead.
427
428	  If in doubt, say Y.
429
430config X86_X2APIC
431	bool "Support x2apic"
432	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
433	help
434	  This enables x2apic support on CPUs that have this feature.
435
436	  This allows 32-bit apic IDs (so it can support very large systems),
437	  and accesses the local apic via MSRs not via mmio.
438
439	  If you don't know what to do here, say N.
440
441config X86_MPPARSE
442	bool "Enable MPS table" if ACPI || SFI
443	default y
444	depends on X86_LOCAL_APIC
445	help
446	  For old smp systems that do not have proper acpi support. Newer systems
447	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
448
449config GOLDFISH
450	def_bool y
451	depends on X86_GOLDFISH
452
453config RETPOLINE
454	bool "Avoid speculative indirect branches in kernel"
455	default y
456	help
457	  Compile kernel with the retpoline compiler options to guard against
458	  kernel-to-user data leaks by avoiding speculative indirect
459	  branches. Requires a compiler with -mindirect-branch=thunk-extern
460	  support for full protection. The kernel may run slower.
461
462config X86_CPU_RESCTRL
463	bool "x86 CPU resource control support"
464	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
465	select KERNFS
466	select PROC_CPU_RESCTRL		if PROC_FS
467	help
468	  Enable x86 CPU resource control support.
469
470	  Provide support for the allocation and monitoring of system resources
471	  usage by the CPU.
472
473	  Intel calls this Intel Resource Director Technology
474	  (Intel(R) RDT). More information about RDT can be found in the
475	  Intel x86 Architecture Software Developer Manual.
476
477	  AMD calls this AMD Platform Quality of Service (AMD QoS).
478	  More information about AMD QoS can be found in the AMD64 Technology
479	  Platform Quality of Service Extensions manual.
480
481	  Say N if unsure.
482
483if X86_32
484config X86_BIGSMP
485	bool "Support for big SMP systems with more than 8 CPUs"
486	depends on SMP
487	help
488	  This option is needed for the systems that have more than 8 CPUs.
489
490config X86_EXTENDED_PLATFORM
491	bool "Support for extended (non-PC) x86 platforms"
492	default y
493	help
494	  If you disable this option then the kernel will only support
495	  standard PC platforms. (which covers the vast majority of
496	  systems out there.)
497
498	  If you enable this option then you'll be able to select support
499	  for the following (non-PC) 32 bit x86 platforms:
500		Goldfish (Android emulator)
501		AMD Elan
502		RDC R-321x SoC
503		SGI 320/540 (Visual Workstation)
504		STA2X11-based (e.g. Northville)
505		Moorestown MID devices
506
507	  If you have one of these systems, or if you want to build a
508	  generic distribution kernel, say Y here - otherwise say N.
509endif
510
511if X86_64
512config X86_EXTENDED_PLATFORM
513	bool "Support for extended (non-PC) x86 platforms"
514	default y
515	help
516	  If you disable this option then the kernel will only support
517	  standard PC platforms. (which covers the vast majority of
518	  systems out there.)
519
520	  If you enable this option then you'll be able to select support
521	  for the following (non-PC) 64 bit x86 platforms:
522		Numascale NumaChip
523		ScaleMP vSMP
524		SGI Ultraviolet
525
526	  If you have one of these systems, or if you want to build a
527	  generic distribution kernel, say Y here - otherwise say N.
528endif
529# This is an alphabetically sorted list of 64 bit extended platforms
530# Please maintain the alphabetic order if and when there are additions
531config X86_NUMACHIP
532	bool "Numascale NumaChip"
533	depends on X86_64
534	depends on X86_EXTENDED_PLATFORM
535	depends on NUMA
536	depends on SMP
537	depends on X86_X2APIC
538	depends on PCI_MMCONFIG
539	help
540	  Adds support for Numascale NumaChip large-SMP systems. Needed to
541	  enable more than ~168 cores.
542	  If you don't have one of these, you should say N here.
543
544config X86_VSMP
545	bool "ScaleMP vSMP"
546	select HYPERVISOR_GUEST
547	select PARAVIRT
548	depends on X86_64 && PCI
549	depends on X86_EXTENDED_PLATFORM
550	depends on SMP
551	help
552	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
553	  supposed to run on these EM64T-based machines.  Only choose this option
554	  if you have one of these machines.
555
556config X86_UV
557	bool "SGI Ultraviolet"
558	depends on X86_64
559	depends on X86_EXTENDED_PLATFORM
560	depends on NUMA
561	depends on EFI
562	depends on X86_X2APIC
563	depends on PCI
564	help
565	  This option is needed in order to support SGI Ultraviolet systems.
566	  If you don't have one of these, you should say N here.
567
568# Following is an alphabetically sorted list of 32 bit extended platforms
569# Please maintain the alphabetic order if and when there are additions
570
571config X86_GOLDFISH
572	bool "Goldfish (Virtual Platform)"
573	depends on X86_EXTENDED_PLATFORM
574	help
575	 Enable support for the Goldfish virtual platform used primarily
576	 for Android development. Unless you are building for the Android
577	 Goldfish emulator say N here.
578
579config X86_INTEL_CE
580	bool "CE4100 TV platform"
581	depends on PCI
582	depends on PCI_GODIRECT
583	depends on X86_IO_APIC
584	depends on X86_32
585	depends on X86_EXTENDED_PLATFORM
586	select X86_REBOOTFIXUPS
587	select OF
588	select OF_EARLY_FLATTREE
589	help
590	  Select for the Intel CE media processor (CE4100) SOC.
591	  This option compiles in support for the CE4100 SOC for settop
592	  boxes and media devices.
593
594config X86_INTEL_MID
595	bool "Intel MID platform support"
596	depends on X86_EXTENDED_PLATFORM
597	depends on X86_PLATFORM_DEVICES
598	depends on PCI
599	depends on X86_64 || (PCI_GOANY && X86_32)
600	depends on X86_IO_APIC
601	select SFI
602	select I2C
603	select DW_APB_TIMER
604	select APB_TIMER
605	select INTEL_SCU_PCI
606	select MFD_INTEL_MSIC
607	help
608	  Select to build a kernel capable of supporting Intel MID (Mobile
609	  Internet Device) platform systems which do not have the PCI legacy
610	  interfaces. If you are building for a PC class system say N here.
611
612	  Intel MID platforms are based on an Intel processor and chipset which
613	  consume less power than most of the x86 derivatives.
614
615config X86_INTEL_QUARK
616	bool "Intel Quark platform support"
617	depends on X86_32
618	depends on X86_EXTENDED_PLATFORM
619	depends on X86_PLATFORM_DEVICES
620	depends on X86_TSC
621	depends on PCI
622	depends on PCI_GOANY
623	depends on X86_IO_APIC
624	select IOSF_MBI
625	select INTEL_IMR
626	select COMMON_CLK
627	help
628	  Select to include support for Quark X1000 SoC.
629	  Say Y here if you have a Quark based system such as the Arduino
630	  compatible Intel Galileo.
631
632config X86_INTEL_LPSS
633	bool "Intel Low Power Subsystem Support"
634	depends on X86 && ACPI && PCI
635	select COMMON_CLK
636	select PINCTRL
637	select IOSF_MBI
638	help
639	  Select to build support for Intel Low Power Subsystem such as
640	  found on Intel Lynxpoint PCH. Selecting this option enables
641	  things like clock tree (common clock framework) and pincontrol
642	  which are needed by the LPSS peripheral drivers.
643
644config X86_AMD_PLATFORM_DEVICE
645	bool "AMD ACPI2Platform devices support"
646	depends on ACPI
647	select COMMON_CLK
648	select PINCTRL
649	help
650	  Select to interpret AMD specific ACPI device to platform device
651	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
652	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
653	  implemented under PINCTRL subsystem.
654
655config IOSF_MBI
656	tristate "Intel SoC IOSF Sideband support for SoC platforms"
657	depends on PCI
658	help
659	  This option enables sideband register access support for Intel SoC
660	  platforms. On these platforms the IOSF sideband is used in lieu of
661	  MSR's for some register accesses, mostly but not limited to thermal
662	  and power. Drivers may query the availability of this device to
663	  determine if they need the sideband in order to work on these
664	  platforms. The sideband is available on the following SoC products.
665	  This list is not meant to be exclusive.
666	   - BayTrail
667	   - Braswell
668	   - Quark
669
670	  You should say Y if you are running a kernel on one of these SoC's.
671
672config IOSF_MBI_DEBUG
673	bool "Enable IOSF sideband access through debugfs"
674	depends on IOSF_MBI && DEBUG_FS
675	help
676	  Select this option to expose the IOSF sideband access registers (MCR,
677	  MDR, MCRX) through debugfs to write and read register information from
678	  different units on the SoC. This is most useful for obtaining device
679	  state information for debug and analysis. As this is a general access
680	  mechanism, users of this option would have specific knowledge of the
681	  device they want to access.
682
683	  If you don't require the option or are in doubt, say N.
684
685config X86_RDC321X
686	bool "RDC R-321x SoC"
687	depends on X86_32
688	depends on X86_EXTENDED_PLATFORM
689	select M486
690	select X86_REBOOTFIXUPS
691	help
692	  This option is needed for RDC R-321x system-on-chip, also known
693	  as R-8610-(G).
694	  If you don't have one of these chips, you should say N here.
695
696config X86_32_NON_STANDARD
697	bool "Support non-standard 32-bit SMP architectures"
698	depends on X86_32 && SMP
699	depends on X86_EXTENDED_PLATFORM
700	help
701	  This option compiles in the bigsmp and STA2X11 default
702	  subarchitectures.  It is intended for a generic binary
703	  kernel. If you select them all, kernel will probe it one by
704	  one and will fallback to default.
705
706# Alphabetically sorted list of Non standard 32 bit platforms
707
708config X86_SUPPORTS_MEMORY_FAILURE
709	def_bool y
710	# MCE code calls memory_failure():
711	depends on X86_MCE
712	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
713	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
714	depends on X86_64 || !SPARSEMEM
715	select ARCH_SUPPORTS_MEMORY_FAILURE
716
717config STA2X11
718	bool "STA2X11 Companion Chip Support"
719	depends on X86_32_NON_STANDARD && PCI
720	select SWIOTLB
721	select MFD_STA2X11
722	select GPIOLIB
723	help
724	  This adds support for boards based on the STA2X11 IO-Hub,
725	  a.k.a. "ConneXt". The chip is used in place of the standard
726	  PC chipset, so all "standard" peripherals are missing. If this
727	  option is selected the kernel will still be able to boot on
728	  standard PC machines.
729
730config X86_32_IRIS
731	tristate "Eurobraille/Iris poweroff module"
732	depends on X86_32
733	help
734	  The Iris machines from EuroBraille do not have APM or ACPI support
735	  to shut themselves down properly.  A special I/O sequence is
736	  needed to do so, which is what this module does at
737	  kernel shutdown.
738
739	  This is only for Iris machines from EuroBraille.
740
741	  If unused, say N.
742
743config SCHED_OMIT_FRAME_POINTER
744	def_bool y
745	prompt "Single-depth WCHAN output"
746	depends on X86
747	help
748	  Calculate simpler /proc/<PID>/wchan values. If this option
749	  is disabled then wchan values will recurse back to the
750	  caller function. This provides more accurate wchan values,
751	  at the expense of slightly more scheduling overhead.
752
753	  If in doubt, say "Y".
754
755menuconfig HYPERVISOR_GUEST
756	bool "Linux guest support"
757	help
758	  Say Y here to enable options for running Linux under various hyper-
759	  visors. This option enables basic hypervisor detection and platform
760	  setup.
761
762	  If you say N, all options in this submenu will be skipped and
763	  disabled, and Linux guest support won't be built in.
764
765if HYPERVISOR_GUEST
766
767config PARAVIRT
768	bool "Enable paravirtualization code"
769	help
770	  This changes the kernel so it can modify itself when it is run
771	  under a hypervisor, potentially improving performance significantly
772	  over full virtualization.  However, when run without a hypervisor
773	  the kernel is theoretically slower and slightly larger.
774
775config PARAVIRT_XXL
776	bool
777
778config PARAVIRT_DEBUG
779	bool "paravirt-ops debugging"
780	depends on PARAVIRT && DEBUG_KERNEL
781	help
782	  Enable to debug paravirt_ops internals.  Specifically, BUG if
783	  a paravirt_op is missing when it is called.
784
785config PARAVIRT_SPINLOCKS
786	bool "Paravirtualization layer for spinlocks"
787	depends on PARAVIRT && SMP
788	help
789	  Paravirtualized spinlocks allow a pvops backend to replace the
790	  spinlock implementation with something virtualization-friendly
791	  (for example, block the virtual CPU rather than spinning).
792
793	  It has a minimal impact on native kernels and gives a nice performance
794	  benefit on paravirtualized KVM / Xen kernels.
795
796	  If you are unsure how to answer this question, answer Y.
797
798config X86_HV_CALLBACK_VECTOR
799	def_bool n
800
801source "arch/x86/xen/Kconfig"
802
803config KVM_GUEST
804	bool "KVM Guest support (including kvmclock)"
805	depends on PARAVIRT
806	select PARAVIRT_CLOCK
807	select ARCH_CPUIDLE_HALTPOLL
808	select X86_HV_CALLBACK_VECTOR
809	default y
810	help
811	  This option enables various optimizations for running under the KVM
812	  hypervisor. It includes a paravirtualized clock, so that instead
813	  of relying on a PIT (or probably other) emulation by the
814	  underlying device model, the host provides the guest with
815	  timing infrastructure such as time of day, and system time
816
817config ARCH_CPUIDLE_HALTPOLL
818	def_bool n
819	prompt "Disable host haltpoll when loading haltpoll driver"
820	help
821	  If virtualized under KVM, disable host haltpoll.
822
823config PVH
824	bool "Support for running PVH guests"
825	help
826	  This option enables the PVH entry point for guest virtual machines
827	  as specified in the x86/HVM direct boot ABI.
828
829config PARAVIRT_TIME_ACCOUNTING
830	bool "Paravirtual steal time accounting"
831	depends on PARAVIRT
832	help
833	  Select this option to enable fine granularity task steal time
834	  accounting. Time spent executing other tasks in parallel with
835	  the current vCPU is discounted from the vCPU power. To account for
836	  that, there can be a small performance impact.
837
838	  If in doubt, say N here.
839
840config PARAVIRT_CLOCK
841	bool
842
843config JAILHOUSE_GUEST
844	bool "Jailhouse non-root cell support"
845	depends on X86_64 && PCI
846	select X86_PM_TIMER
847	help
848	  This option allows to run Linux as guest in a Jailhouse non-root
849	  cell. You can leave this option disabled if you only want to start
850	  Jailhouse and run Linux afterwards in the root cell.
851
852config ACRN_GUEST
853	bool "ACRN Guest support"
854	depends on X86_64
855	select X86_HV_CALLBACK_VECTOR
856	help
857	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
858	  a flexible, lightweight reference open-source hypervisor, built with
859	  real-time and safety-criticality in mind. It is built for embedded
860	  IOT with small footprint and real-time features. More details can be
861	  found in https://projectacrn.org/.
862
863endif #HYPERVISOR_GUEST
864
865source "arch/x86/Kconfig.cpu"
866
867config HPET_TIMER
868	def_bool X86_64
869	prompt "HPET Timer Support" if X86_32
870	help
871	  Use the IA-PC HPET (High Precision Event Timer) to manage
872	  time in preference to the PIT and RTC, if a HPET is
873	  present.
874	  HPET is the next generation timer replacing legacy 8254s.
875	  The HPET provides a stable time base on SMP
876	  systems, unlike the TSC, but it is more expensive to access,
877	  as it is off-chip.  The interface used is documented
878	  in the HPET spec, revision 1.
879
880	  You can safely choose Y here.  However, HPET will only be
881	  activated if the platform and the BIOS support this feature.
882	  Otherwise the 8254 will be used for timing services.
883
884	  Choose N to continue using the legacy 8254 timer.
885
886config HPET_EMULATE_RTC
887	def_bool y
888	depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
889
890config APB_TIMER
891	def_bool y if X86_INTEL_MID
892	prompt "Intel MID APB Timer Support" if X86_INTEL_MID
893	select DW_APB_TIMER
894	depends on X86_INTEL_MID && SFI
895	help
896	 APB timer is the replacement for 8254, HPET on X86 MID platforms.
897	 The APBT provides a stable time base on SMP
898	 systems, unlike the TSC, but it is more expensive to access,
899	 as it is off-chip. APB timers are always running regardless of CPU
900	 C states, they are used as per CPU clockevent device when possible.
901
902# Mark as expert because too many people got it wrong.
903# The code disables itself when not needed.
904config DMI
905	default y
906	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
907	bool "Enable DMI scanning" if EXPERT
908	help
909	  Enabled scanning of DMI to identify machine quirks. Say Y
910	  here unless you have verified that your setup is not
911	  affected by entries in the DMI blacklist. Required by PNP
912	  BIOS code.
913
914config GART_IOMMU
915	bool "Old AMD GART IOMMU support"
916	select DMA_OPS
917	select IOMMU_HELPER
918	select SWIOTLB
919	depends on X86_64 && PCI && AMD_NB
920	help
921	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
922	  GART based hardware IOMMUs.
923
924	  The GART supports full DMA access for devices with 32-bit access
925	  limitations, on systems with more than 3 GB. This is usually needed
926	  for USB, sound, many IDE/SATA chipsets and some other devices.
927
928	  Newer systems typically have a modern AMD IOMMU, supported via
929	  the CONFIG_AMD_IOMMU=y config option.
930
931	  In normal configurations this driver is only active when needed:
932	  there's more than 3 GB of memory and the system contains a
933	  32-bit limited device.
934
935	  If unsure, say Y.
936
937config MAXSMP
938	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
939	depends on X86_64 && SMP && DEBUG_KERNEL
940	select CPUMASK_OFFSTACK
941	help
942	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
943	  If unsure, say N.
944
945#
946# The maximum number of CPUs supported:
947#
948# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
949# and which can be configured interactively in the
950# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
951#
952# The ranges are different on 32-bit and 64-bit kernels, depending on
953# hardware capabilities and scalability features of the kernel.
954#
955# ( If MAXSMP is enabled we just use the highest possible value and disable
956#   interactive configuration. )
957#
958
959config NR_CPUS_RANGE_BEGIN
960	int
961	default NR_CPUS_RANGE_END if MAXSMP
962	default    1 if !SMP
963	default    2
964
965config NR_CPUS_RANGE_END
966	int
967	depends on X86_32
968	default   64 if  SMP &&  X86_BIGSMP
969	default    8 if  SMP && !X86_BIGSMP
970	default    1 if !SMP
971
972config NR_CPUS_RANGE_END
973	int
974	depends on X86_64
975	default 8192 if  SMP && CPUMASK_OFFSTACK
976	default  512 if  SMP && !CPUMASK_OFFSTACK
977	default    1 if !SMP
978
979config NR_CPUS_DEFAULT
980	int
981	depends on X86_32
982	default   32 if  X86_BIGSMP
983	default    8 if  SMP
984	default    1 if !SMP
985
986config NR_CPUS_DEFAULT
987	int
988	depends on X86_64
989	default 8192 if  MAXSMP
990	default   64 if  SMP
991	default    1 if !SMP
992
993config NR_CPUS
994	int "Maximum number of CPUs" if SMP && !MAXSMP
995	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
996	default NR_CPUS_DEFAULT
997	help
998	  This allows you to specify the maximum number of CPUs which this
999	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1000	  supported value is 8192, otherwise the maximum value is 512.  The
1001	  minimum value which makes sense is 2.
1002
1003	  This is purely to save memory: each supported CPU adds about 8KB
1004	  to the kernel image.
1005
1006config SCHED_SMT
1007	def_bool y if SMP
1008
1009config SCHED_MC
1010	def_bool y
1011	prompt "Multi-core scheduler support"
1012	depends on SMP
1013	help
1014	  Multi-core scheduler support improves the CPU scheduler's decision
1015	  making when dealing with multi-core CPU chips at a cost of slightly
1016	  increased overhead in some places. If unsure say N here.
1017
1018config SCHED_MC_PRIO
1019	bool "CPU core priorities scheduler support"
1020	depends on SCHED_MC && CPU_SUP_INTEL
1021	select X86_INTEL_PSTATE
1022	select CPU_FREQ
1023	default y
1024	help
1025	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1026	  core ordering determined at manufacturing time, which allows
1027	  certain cores to reach higher turbo frequencies (when running
1028	  single threaded workloads) than others.
1029
1030	  Enabling this kernel feature teaches the scheduler about
1031	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1032	  scheduler's CPU selection logic accordingly, so that higher
1033	  overall system performance can be achieved.
1034
1035	  This feature will have no effect on CPUs without this feature.
1036
1037	  If unsure say Y here.
1038
1039config UP_LATE_INIT
1040	def_bool y
1041	depends on !SMP && X86_LOCAL_APIC
1042
1043config X86_UP_APIC
1044	bool "Local APIC support on uniprocessors" if !PCI_MSI
1045	default PCI_MSI
1046	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1047	help
1048	  A local APIC (Advanced Programmable Interrupt Controller) is an
1049	  integrated interrupt controller in the CPU. If you have a single-CPU
1050	  system which has a processor with a local APIC, you can say Y here to
1051	  enable and use it. If you say Y here even though your machine doesn't
1052	  have a local APIC, then the kernel will still run with no slowdown at
1053	  all. The local APIC supports CPU-generated self-interrupts (timer,
1054	  performance counters), and the NMI watchdog which detects hard
1055	  lockups.
1056
1057config X86_UP_IOAPIC
1058	bool "IO-APIC support on uniprocessors"
1059	depends on X86_UP_APIC
1060	help
1061	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1062	  SMP-capable replacement for PC-style interrupt controllers. Most
1063	  SMP systems and many recent uniprocessor systems have one.
1064
1065	  If you have a single-CPU system with an IO-APIC, you can say Y here
1066	  to use it. If you say Y here even though your machine doesn't have
1067	  an IO-APIC, then the kernel will still run with no slowdown at all.
1068
1069config X86_LOCAL_APIC
1070	def_bool y
1071	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1072	select IRQ_DOMAIN_HIERARCHY
1073	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1074
1075config X86_IO_APIC
1076	def_bool y
1077	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1078
1079config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1080	bool "Reroute for broken boot IRQs"
1081	depends on X86_IO_APIC
1082	help
1083	  This option enables a workaround that fixes a source of
1084	  spurious interrupts. This is recommended when threaded
1085	  interrupt handling is used on systems where the generation of
1086	  superfluous "boot interrupts" cannot be disabled.
1087
1088	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1089	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1090	  kernel does during interrupt handling). On chipsets where this
1091	  boot IRQ generation cannot be disabled, this workaround keeps
1092	  the original IRQ line masked so that only the equivalent "boot
1093	  IRQ" is delivered to the CPUs. The workaround also tells the
1094	  kernel to set up the IRQ handler on the boot IRQ line. In this
1095	  way only one interrupt is delivered to the kernel. Otherwise
1096	  the spurious second interrupt may cause the kernel to bring
1097	  down (vital) interrupt lines.
1098
1099	  Only affects "broken" chipsets. Interrupt sharing may be
1100	  increased on these systems.
1101
1102config X86_MCE
1103	bool "Machine Check / overheating reporting"
1104	select GENERIC_ALLOCATOR
1105	default y
1106	help
1107	  Machine Check support allows the processor to notify the
1108	  kernel if it detects a problem (e.g. overheating, data corruption).
1109	  The action the kernel takes depends on the severity of the problem,
1110	  ranging from warning messages to halting the machine.
1111
1112config X86_MCELOG_LEGACY
1113	bool "Support for deprecated /dev/mcelog character device"
1114	depends on X86_MCE
1115	help
1116	  Enable support for /dev/mcelog which is needed by the old mcelog
1117	  userspace logging daemon. Consider switching to the new generation
1118	  rasdaemon solution.
1119
1120config X86_MCE_INTEL
1121	def_bool y
1122	prompt "Intel MCE features"
1123	depends on X86_MCE && X86_LOCAL_APIC
1124	help
1125	   Additional support for intel specific MCE features such as
1126	   the thermal monitor.
1127
1128config X86_MCE_AMD
1129	def_bool y
1130	prompt "AMD MCE features"
1131	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1132	help
1133	   Additional support for AMD specific MCE features such as
1134	   the DRAM Error Threshold.
1135
1136config X86_ANCIENT_MCE
1137	bool "Support for old Pentium 5 / WinChip machine checks"
1138	depends on X86_32 && X86_MCE
1139	help
1140	  Include support for machine check handling on old Pentium 5 or WinChip
1141	  systems. These typically need to be enabled explicitly on the command
1142	  line.
1143
1144config X86_MCE_THRESHOLD
1145	depends on X86_MCE_AMD || X86_MCE_INTEL
1146	def_bool y
1147
1148config X86_MCE_INJECT
1149	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1150	tristate "Machine check injector support"
1151	help
1152	  Provide support for injecting machine checks for testing purposes.
1153	  If you don't know what a machine check is and you don't do kernel
1154	  QA it is safe to say n.
1155
1156config X86_THERMAL_VECTOR
1157	def_bool y
1158	depends on X86_MCE_INTEL
1159
1160source "arch/x86/events/Kconfig"
1161
1162config X86_LEGACY_VM86
1163	bool "Legacy VM86 support"
1164	depends on X86_32
1165	help
1166	  This option allows user programs to put the CPU into V8086
1167	  mode, which is an 80286-era approximation of 16-bit real mode.
1168
1169	  Some very old versions of X and/or vbetool require this option
1170	  for user mode setting.  Similarly, DOSEMU will use it if
1171	  available to accelerate real mode DOS programs.  However, any
1172	  recent version of DOSEMU, X, or vbetool should be fully
1173	  functional even without kernel VM86 support, as they will all
1174	  fall back to software emulation. Nevertheless, if you are using
1175	  a 16-bit DOS program where 16-bit performance matters, vm86
1176	  mode might be faster than emulation and you might want to
1177	  enable this option.
1178
1179	  Note that any app that works on a 64-bit kernel is unlikely to
1180	  need this option, as 64-bit kernels don't, and can't, support
1181	  V8086 mode. This option is also unrelated to 16-bit protected
1182	  mode and is not needed to run most 16-bit programs under Wine.
1183
1184	  Enabling this option increases the complexity of the kernel
1185	  and slows down exception handling a tiny bit.
1186
1187	  If unsure, say N here.
1188
1189config VM86
1190	bool
1191	default X86_LEGACY_VM86
1192
1193config X86_16BIT
1194	bool "Enable support for 16-bit segments" if EXPERT
1195	default y
1196	depends on MODIFY_LDT_SYSCALL
1197	help
1198	  This option is required by programs like Wine to run 16-bit
1199	  protected mode legacy code on x86 processors.  Disabling
1200	  this option saves about 300 bytes on i386, or around 6K text
1201	  plus 16K runtime memory on x86-64,
1202
1203config X86_ESPFIX32
1204	def_bool y
1205	depends on X86_16BIT && X86_32
1206
1207config X86_ESPFIX64
1208	def_bool y
1209	depends on X86_16BIT && X86_64
1210
1211config X86_VSYSCALL_EMULATION
1212	bool "Enable vsyscall emulation" if EXPERT
1213	default y
1214	depends on X86_64
1215	help
1216	 This enables emulation of the legacy vsyscall page.  Disabling
1217	 it is roughly equivalent to booting with vsyscall=none, except
1218	 that it will also disable the helpful warning if a program
1219	 tries to use a vsyscall.  With this option set to N, offending
1220	 programs will just segfault, citing addresses of the form
1221	 0xffffffffff600?00.
1222
1223	 This option is required by many programs built before 2013, and
1224	 care should be used even with newer programs if set to N.
1225
1226	 Disabling this option saves about 7K of kernel size and
1227	 possibly 4K of additional runtime pagetable memory.
1228
1229config X86_IOPL_IOPERM
1230	bool "IOPERM and IOPL Emulation"
1231	default y
1232	help
1233	  This enables the ioperm() and iopl() syscalls which are necessary
1234	  for legacy applications.
1235
1236	  Legacy IOPL support is an overbroad mechanism which allows user
1237	  space aside of accessing all 65536 I/O ports also to disable
1238	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1239	  capabilities and permission from potentially active security
1240	  modules.
1241
1242	  The emulation restricts the functionality of the syscall to
1243	  only allowing the full range I/O port access, but prevents the
1244	  ability to disable interrupts from user space which would be
1245	  granted if the hardware IOPL mechanism would be used.
1246
1247config TOSHIBA
1248	tristate "Toshiba Laptop support"
1249	depends on X86_32
1250	help
1251	  This adds a driver to safely access the System Management Mode of
1252	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1253	  not work on models with a Phoenix BIOS. The System Management Mode
1254	  is used to set the BIOS and power saving options on Toshiba portables.
1255
1256	  For information on utilities to make use of this driver see the
1257	  Toshiba Linux utilities web site at:
1258	  <http://www.buzzard.org.uk/toshiba/>.
1259
1260	  Say Y if you intend to run this kernel on a Toshiba portable.
1261	  Say N otherwise.
1262
1263config I8K
1264	tristate "Dell i8k legacy laptop support"
1265	select HWMON
1266	select SENSORS_DELL_SMM
1267	help
1268	  This option enables legacy /proc/i8k userspace interface in hwmon
1269	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1270	  temperature and allows controlling fan speeds of Dell laptops via
1271	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1272	  it reports also power and hotkey status. For fan speed control is
1273	  needed userspace package i8kutils.
1274
1275	  Say Y if you intend to run this kernel on old Dell laptops or want to
1276	  use userspace package i8kutils.
1277	  Say N otherwise.
1278
1279config X86_REBOOTFIXUPS
1280	bool "Enable X86 board specific fixups for reboot"
1281	depends on X86_32
1282	help
1283	  This enables chipset and/or board specific fixups to be done
1284	  in order to get reboot to work correctly. This is only needed on
1285	  some combinations of hardware and BIOS. The symptom, for which
1286	  this config is intended, is when reboot ends with a stalled/hung
1287	  system.
1288
1289	  Currently, the only fixup is for the Geode machines using
1290	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1291
1292	  Say Y if you want to enable the fixup. Currently, it's safe to
1293	  enable this option even if you don't need it.
1294	  Say N otherwise.
1295
1296config MICROCODE
1297	bool "CPU microcode loading support"
1298	default y
1299	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1300	help
1301	  If you say Y here, you will be able to update the microcode on
1302	  Intel and AMD processors. The Intel support is for the IA32 family,
1303	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1304	  AMD support is for families 0x10 and later. You will obviously need
1305	  the actual microcode binary data itself which is not shipped with
1306	  the Linux kernel.
1307
1308	  The preferred method to load microcode from a detached initrd is described
1309	  in Documentation/x86/microcode.rst. For that you need to enable
1310	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1311	  initrd for microcode blobs.
1312
1313	  In addition, you can build the microcode into the kernel. For that you
1314	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1315	  config option.
1316
1317config MICROCODE_INTEL
1318	bool "Intel microcode loading support"
1319	depends on MICROCODE
1320	default MICROCODE
1321	help
1322	  This options enables microcode patch loading support for Intel
1323	  processors.
1324
1325	  For the current Intel microcode data package go to
1326	  <https://downloadcenter.intel.com> and search for
1327	  'Linux Processor Microcode Data File'.
1328
1329config MICROCODE_AMD
1330	bool "AMD microcode loading support"
1331	depends on MICROCODE
1332	help
1333	  If you select this option, microcode patch loading support for AMD
1334	  processors will be enabled.
1335
1336config MICROCODE_OLD_INTERFACE
1337	bool "Ancient loading interface (DEPRECATED)"
1338	default n
1339	depends on MICROCODE
1340	help
1341	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1342	  which was used by userspace tools like iucode_tool and microcode.ctl.
1343	  It is inadequate because it runs too late to be able to properly
1344	  load microcode on a machine and it needs special tools. Instead, you
1345	  should've switched to the early loading method with the initrd or
1346	  builtin microcode by now: Documentation/x86/microcode.rst
1347
1348config X86_MSR
1349	tristate "/dev/cpu/*/msr - Model-specific register support"
1350	help
1351	  This device gives privileged processes access to the x86
1352	  Model-Specific Registers (MSRs).  It is a character device with
1353	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1354	  MSR accesses are directed to a specific CPU on multi-processor
1355	  systems.
1356
1357config X86_CPUID
1358	tristate "/dev/cpu/*/cpuid - CPU information support"
1359	help
1360	  This device gives processes access to the x86 CPUID instruction to
1361	  be executed on a specific processor.  It is a character device
1362	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1363	  /dev/cpu/31/cpuid.
1364
1365choice
1366	prompt "High Memory Support"
1367	default HIGHMEM4G
1368	depends on X86_32
1369
1370config NOHIGHMEM
1371	bool "off"
1372	help
1373	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1374	  However, the address space of 32-bit x86 processors is only 4
1375	  Gigabytes large. That means that, if you have a large amount of
1376	  physical memory, not all of it can be "permanently mapped" by the
1377	  kernel. The physical memory that's not permanently mapped is called
1378	  "high memory".
1379
1380	  If you are compiling a kernel which will never run on a machine with
1381	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1382	  choice and suitable for most users). This will result in a "3GB/1GB"
1383	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1384	  space and the remaining part of the 4GB virtual memory space is used
1385	  by the kernel to permanently map as much physical memory as
1386	  possible.
1387
1388	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1389	  answer "4GB" here.
1390
1391	  If more than 4 Gigabytes is used then answer "64GB" here. This
1392	  selection turns Intel PAE (Physical Address Extension) mode on.
1393	  PAE implements 3-level paging on IA32 processors. PAE is fully
1394	  supported by Linux, PAE mode is implemented on all recent Intel
1395	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1396	  then the kernel will not boot on CPUs that don't support PAE!
1397
1398	  The actual amount of total physical memory will either be
1399	  auto detected or can be forced by using a kernel command line option
1400	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1401	  your boot loader (lilo or loadlin) about how to pass options to the
1402	  kernel at boot time.)
1403
1404	  If unsure, say "off".
1405
1406config HIGHMEM4G
1407	bool "4GB"
1408	help
1409	  Select this if you have a 32-bit processor and between 1 and 4
1410	  gigabytes of physical RAM.
1411
1412config HIGHMEM64G
1413	bool "64GB"
1414	depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1415	select X86_PAE
1416	help
1417	  Select this if you have a 32-bit processor and more than 4
1418	  gigabytes of physical RAM.
1419
1420endchoice
1421
1422choice
1423	prompt "Memory split" if EXPERT
1424	default VMSPLIT_3G
1425	depends on X86_32
1426	help
1427	  Select the desired split between kernel and user memory.
1428
1429	  If the address range available to the kernel is less than the
1430	  physical memory installed, the remaining memory will be available
1431	  as "high memory". Accessing high memory is a little more costly
1432	  than low memory, as it needs to be mapped into the kernel first.
1433	  Note that increasing the kernel address space limits the range
1434	  available to user programs, making the address space there
1435	  tighter.  Selecting anything other than the default 3G/1G split
1436	  will also likely make your kernel incompatible with binary-only
1437	  kernel modules.
1438
1439	  If you are not absolutely sure what you are doing, leave this
1440	  option alone!
1441
1442	config VMSPLIT_3G
1443		bool "3G/1G user/kernel split"
1444	config VMSPLIT_3G_OPT
1445		depends on !X86_PAE
1446		bool "3G/1G user/kernel split (for full 1G low memory)"
1447	config VMSPLIT_2G
1448		bool "2G/2G user/kernel split"
1449	config VMSPLIT_2G_OPT
1450		depends on !X86_PAE
1451		bool "2G/2G user/kernel split (for full 2G low memory)"
1452	config VMSPLIT_1G
1453		bool "1G/3G user/kernel split"
1454endchoice
1455
1456config PAGE_OFFSET
1457	hex
1458	default 0xB0000000 if VMSPLIT_3G_OPT
1459	default 0x80000000 if VMSPLIT_2G
1460	default 0x78000000 if VMSPLIT_2G_OPT
1461	default 0x40000000 if VMSPLIT_1G
1462	default 0xC0000000
1463	depends on X86_32
1464
1465config HIGHMEM
1466	def_bool y
1467	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1468
1469config X86_PAE
1470	bool "PAE (Physical Address Extension) Support"
1471	depends on X86_32 && !HIGHMEM4G
1472	select PHYS_ADDR_T_64BIT
1473	select SWIOTLB
1474	help
1475	  PAE is required for NX support, and furthermore enables
1476	  larger swapspace support for non-overcommit purposes. It
1477	  has the cost of more pagetable lookup overhead, and also
1478	  consumes more pagetable space per process.
1479
1480config X86_5LEVEL
1481	bool "Enable 5-level page tables support"
1482	default y
1483	select DYNAMIC_MEMORY_LAYOUT
1484	select SPARSEMEM_VMEMMAP
1485	depends on X86_64
1486	help
1487	  5-level paging enables access to larger address space:
1488	  upto 128 PiB of virtual address space and 4 PiB of
1489	  physical address space.
1490
1491	  It will be supported by future Intel CPUs.
1492
1493	  A kernel with the option enabled can be booted on machines that
1494	  support 4- or 5-level paging.
1495
1496	  See Documentation/x86/x86_64/5level-paging.rst for more
1497	  information.
1498
1499	  Say N if unsure.
1500
1501config X86_DIRECT_GBPAGES
1502	def_bool y
1503	depends on X86_64
1504	help
1505	  Certain kernel features effectively disable kernel
1506	  linear 1 GB mappings (even if the CPU otherwise
1507	  supports them), so don't confuse the user by printing
1508	  that we have them enabled.
1509
1510config X86_CPA_STATISTICS
1511	bool "Enable statistic for Change Page Attribute"
1512	depends on DEBUG_FS
1513	help
1514	  Expose statistics about the Change Page Attribute mechanism, which
1515	  helps to determine the effectiveness of preserving large and huge
1516	  page mappings when mapping protections are changed.
1517
1518config AMD_MEM_ENCRYPT
1519	bool "AMD Secure Memory Encryption (SME) support"
1520	depends on X86_64 && CPU_SUP_AMD
1521	select DMA_COHERENT_POOL
1522	select DYNAMIC_PHYSICAL_MASK
1523	select ARCH_USE_MEMREMAP_PROT
1524	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1525	select INSTRUCTION_DECODER
1526	help
1527	  Say yes to enable support for the encryption of system memory.
1528	  This requires an AMD processor that supports Secure Memory
1529	  Encryption (SME).
1530
1531config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1532	bool "Activate AMD Secure Memory Encryption (SME) by default"
1533	default y
1534	depends on AMD_MEM_ENCRYPT
1535	help
1536	  Say yes to have system memory encrypted by default if running on
1537	  an AMD processor that supports Secure Memory Encryption (SME).
1538
1539	  If set to Y, then the encryption of system memory can be
1540	  deactivated with the mem_encrypt=off command line option.
1541
1542	  If set to N, then the encryption of system memory can be
1543	  activated with the mem_encrypt=on command line option.
1544
1545# Common NUMA Features
1546config NUMA
1547	bool "NUMA Memory Allocation and Scheduler Support"
1548	depends on SMP
1549	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1550	default y if X86_BIGSMP
1551	help
1552	  Enable NUMA (Non-Uniform Memory Access) support.
1553
1554	  The kernel will try to allocate memory used by a CPU on the
1555	  local memory controller of the CPU and add some more
1556	  NUMA awareness to the kernel.
1557
1558	  For 64-bit this is recommended if the system is Intel Core i7
1559	  (or later), AMD Opteron, or EM64T NUMA.
1560
1561	  For 32-bit this is only needed if you boot a 32-bit
1562	  kernel on a 64-bit NUMA platform.
1563
1564	  Otherwise, you should say N.
1565
1566config AMD_NUMA
1567	def_bool y
1568	prompt "Old style AMD Opteron NUMA detection"
1569	depends on X86_64 && NUMA && PCI
1570	help
1571	  Enable AMD NUMA node topology detection.  You should say Y here if
1572	  you have a multi processor AMD system. This uses an old method to
1573	  read the NUMA configuration directly from the builtin Northbridge
1574	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1575	  which also takes priority if both are compiled in.
1576
1577config X86_64_ACPI_NUMA
1578	def_bool y
1579	prompt "ACPI NUMA detection"
1580	depends on X86_64 && NUMA && ACPI && PCI
1581	select ACPI_NUMA
1582	help
1583	  Enable ACPI SRAT based node topology detection.
1584
1585config NUMA_EMU
1586	bool "NUMA emulation"
1587	depends on NUMA
1588	help
1589	  Enable NUMA emulation. A flat machine will be split
1590	  into virtual nodes when booted with "numa=fake=N", where N is the
1591	  number of nodes. This is only useful for debugging.
1592
1593config NODES_SHIFT
1594	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1595	range 1 10
1596	default "10" if MAXSMP
1597	default "6" if X86_64
1598	default "3"
1599	depends on NEED_MULTIPLE_NODES
1600	help
1601	  Specify the maximum number of NUMA Nodes available on the target
1602	  system.  Increases memory reserved to accommodate various tables.
1603
1604config ARCH_FLATMEM_ENABLE
1605	def_bool y
1606	depends on X86_32 && !NUMA
1607
1608config ARCH_SPARSEMEM_ENABLE
1609	def_bool y
1610	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1611	select SPARSEMEM_STATIC if X86_32
1612	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1613
1614config ARCH_SPARSEMEM_DEFAULT
1615	def_bool X86_64 || (NUMA && X86_32)
1616
1617config ARCH_SELECT_MEMORY_MODEL
1618	def_bool y
1619	depends on ARCH_SPARSEMEM_ENABLE
1620
1621config ARCH_MEMORY_PROBE
1622	bool "Enable sysfs memory/probe interface"
1623	depends on X86_64 && MEMORY_HOTPLUG
1624	help
1625	  This option enables a sysfs memory/probe interface for testing.
1626	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1627	  If you are unsure how to answer this question, answer N.
1628
1629config ARCH_PROC_KCORE_TEXT
1630	def_bool y
1631	depends on X86_64 && PROC_KCORE
1632
1633config ILLEGAL_POINTER_VALUE
1634	hex
1635	default 0 if X86_32
1636	default 0xdead000000000000 if X86_64
1637
1638config X86_PMEM_LEGACY_DEVICE
1639	bool
1640
1641config X86_PMEM_LEGACY
1642	tristate "Support non-standard NVDIMMs and ADR protected memory"
1643	depends on PHYS_ADDR_T_64BIT
1644	depends on BLK_DEV
1645	select X86_PMEM_LEGACY_DEVICE
1646	select NUMA_KEEP_MEMINFO if NUMA
1647	select LIBNVDIMM
1648	help
1649	  Treat memory marked using the non-standard e820 type of 12 as used
1650	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1651	  The kernel will offer these regions to the 'pmem' driver so
1652	  they can be used for persistent storage.
1653
1654	  Say Y if unsure.
1655
1656config HIGHPTE
1657	bool "Allocate 3rd-level pagetables from highmem"
1658	depends on HIGHMEM
1659	help
1660	  The VM uses one page table entry for each page of physical memory.
1661	  For systems with a lot of RAM, this can be wasteful of precious
1662	  low memory.  Setting this option will put user-space page table
1663	  entries in high memory.
1664
1665config X86_CHECK_BIOS_CORRUPTION
1666	bool "Check for low memory corruption"
1667	help
1668	  Periodically check for memory corruption in low memory, which
1669	  is suspected to be caused by BIOS.  Even when enabled in the
1670	  configuration, it is disabled at runtime.  Enable it by
1671	  setting "memory_corruption_check=1" on the kernel command
1672	  line.  By default it scans the low 64k of memory every 60
1673	  seconds; see the memory_corruption_check_size and
1674	  memory_corruption_check_period parameters in
1675	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1676
1677	  When enabled with the default parameters, this option has
1678	  almost no overhead, as it reserves a relatively small amount
1679	  of memory and scans it infrequently.  It both detects corruption
1680	  and prevents it from affecting the running system.
1681
1682	  It is, however, intended as a diagnostic tool; if repeatable
1683	  BIOS-originated corruption always affects the same memory,
1684	  you can use memmap= to prevent the kernel from using that
1685	  memory.
1686
1687config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1688	bool "Set the default setting of memory_corruption_check"
1689	depends on X86_CHECK_BIOS_CORRUPTION
1690	default y
1691	help
1692	  Set whether the default state of memory_corruption_check is
1693	  on or off.
1694
1695config X86_RESERVE_LOW
1696	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1697	default 64
1698	range 4 640
1699	help
1700	  Specify the amount of low memory to reserve for the BIOS.
1701
1702	  The first page contains BIOS data structures that the kernel
1703	  must not use, so that page must always be reserved.
1704
1705	  By default we reserve the first 64K of physical RAM, as a
1706	  number of BIOSes are known to corrupt that memory range
1707	  during events such as suspend/resume or monitor cable
1708	  insertion, so it must not be used by the kernel.
1709
1710	  You can set this to 4 if you are absolutely sure that you
1711	  trust the BIOS to get all its memory reservations and usages
1712	  right.  If you know your BIOS have problems beyond the
1713	  default 64K area, you can set this to 640 to avoid using the
1714	  entire low memory range.
1715
1716	  If you have doubts about the BIOS (e.g. suspend/resume does
1717	  not work or there's kernel crashes after certain hardware
1718	  hotplug events) then you might want to enable
1719	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1720	  typical corruption patterns.
1721
1722	  Leave this to the default value of 64 if you are unsure.
1723
1724config MATH_EMULATION
1725	bool
1726	depends on MODIFY_LDT_SYSCALL
1727	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1728	help
1729	  Linux can emulate a math coprocessor (used for floating point
1730	  operations) if you don't have one. 486DX and Pentium processors have
1731	  a math coprocessor built in, 486SX and 386 do not, unless you added
1732	  a 487DX or 387, respectively. (The messages during boot time can
1733	  give you some hints here ["man dmesg"].) Everyone needs either a
1734	  coprocessor or this emulation.
1735
1736	  If you don't have a math coprocessor, you need to say Y here; if you
1737	  say Y here even though you have a coprocessor, the coprocessor will
1738	  be used nevertheless. (This behavior can be changed with the kernel
1739	  command line option "no387", which comes handy if your coprocessor
1740	  is broken. Try "man bootparam" or see the documentation of your boot
1741	  loader (lilo or loadlin) about how to pass options to the kernel at
1742	  boot time.) This means that it is a good idea to say Y here if you
1743	  intend to use this kernel on different machines.
1744
1745	  More information about the internals of the Linux math coprocessor
1746	  emulation can be found in <file:arch/x86/math-emu/README>.
1747
1748	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1749	  kernel, it won't hurt.
1750
1751config MTRR
1752	def_bool y
1753	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1754	help
1755	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1756	  the Memory Type Range Registers (MTRRs) may be used to control
1757	  processor access to memory ranges. This is most useful if you have
1758	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1759	  allows bus write transfers to be combined into a larger transfer
1760	  before bursting over the PCI/AGP bus. This can increase performance
1761	  of image write operations 2.5 times or more. Saying Y here creates a
1762	  /proc/mtrr file which may be used to manipulate your processor's
1763	  MTRRs. Typically the X server should use this.
1764
1765	  This code has a reasonably generic interface so that similar
1766	  control registers on other processors can be easily supported
1767	  as well:
1768
1769	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1770	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1771	  these, the ARRs are used to emulate the MTRRs.
1772	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1773	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1774	  write-combining. All of these processors are supported by this code
1775	  and it makes sense to say Y here if you have one of them.
1776
1777	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1778	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1779	  can lead to all sorts of problems, so it's good to say Y here.
1780
1781	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1782	  just add about 9 KB to your kernel.
1783
1784	  See <file:Documentation/x86/mtrr.rst> for more information.
1785
1786config MTRR_SANITIZER
1787	def_bool y
1788	prompt "MTRR cleanup support"
1789	depends on MTRR
1790	help
1791	  Convert MTRR layout from continuous to discrete, so X drivers can
1792	  add writeback entries.
1793
1794	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1795	  The largest mtrr entry size for a continuous block can be set with
1796	  mtrr_chunk_size.
1797
1798	  If unsure, say Y.
1799
1800config MTRR_SANITIZER_ENABLE_DEFAULT
1801	int "MTRR cleanup enable value (0-1)"
1802	range 0 1
1803	default "0"
1804	depends on MTRR_SANITIZER
1805	help
1806	  Enable mtrr cleanup default value
1807
1808config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1809	int "MTRR cleanup spare reg num (0-7)"
1810	range 0 7
1811	default "1"
1812	depends on MTRR_SANITIZER
1813	help
1814	  mtrr cleanup spare entries default, it can be changed via
1815	  mtrr_spare_reg_nr=N on the kernel command line.
1816
1817config X86_PAT
1818	def_bool y
1819	prompt "x86 PAT support" if EXPERT
1820	depends on MTRR
1821	help
1822	  Use PAT attributes to setup page level cache control.
1823
1824	  PATs are the modern equivalents of MTRRs and are much more
1825	  flexible than MTRRs.
1826
1827	  Say N here if you see bootup problems (boot crash, boot hang,
1828	  spontaneous reboots) or a non-working video driver.
1829
1830	  If unsure, say Y.
1831
1832config ARCH_USES_PG_UNCACHED
1833	def_bool y
1834	depends on X86_PAT
1835
1836config ARCH_RANDOM
1837	def_bool y
1838	prompt "x86 architectural random number generator" if EXPERT
1839	help
1840	  Enable the x86 architectural RDRAND instruction
1841	  (Intel Bull Mountain technology) to generate random numbers.
1842	  If supported, this is a high bandwidth, cryptographically
1843	  secure hardware random number generator.
1844
1845config X86_SMAP
1846	def_bool y
1847	prompt "Supervisor Mode Access Prevention" if EXPERT
1848	help
1849	  Supervisor Mode Access Prevention (SMAP) is a security
1850	  feature in newer Intel processors.  There is a small
1851	  performance cost if this enabled and turned on; there is
1852	  also a small increase in the kernel size if this is enabled.
1853
1854	  If unsure, say Y.
1855
1856config X86_UMIP
1857	def_bool y
1858	prompt "User Mode Instruction Prevention" if EXPERT
1859	help
1860	  User Mode Instruction Prevention (UMIP) is a security feature in
1861	  some x86 processors. If enabled, a general protection fault is
1862	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1863	  executed in user mode. These instructions unnecessarily expose
1864	  information about the hardware state.
1865
1866	  The vast majority of applications do not use these instructions.
1867	  For the very few that do, software emulation is provided in
1868	  specific cases in protected and virtual-8086 modes. Emulated
1869	  results are dummy.
1870
1871config X86_INTEL_MEMORY_PROTECTION_KEYS
1872	prompt "Memory Protection Keys"
1873	def_bool y
1874	# Note: only available in 64-bit mode
1875	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1876	select ARCH_USES_HIGH_VMA_FLAGS
1877	select ARCH_HAS_PKEYS
1878	help
1879	  Memory Protection Keys provides a mechanism for enforcing
1880	  page-based protections, but without requiring modification of the
1881	  page tables when an application changes protection domains.
1882
1883	  For details, see Documentation/core-api/protection-keys.rst
1884
1885	  If unsure, say y.
1886
1887choice
1888	prompt "TSX enable mode"
1889	depends on CPU_SUP_INTEL
1890	default X86_INTEL_TSX_MODE_OFF
1891	help
1892	  Intel's TSX (Transactional Synchronization Extensions) feature
1893	  allows to optimize locking protocols through lock elision which
1894	  can lead to a noticeable performance boost.
1895
1896	  On the other hand it has been shown that TSX can be exploited
1897	  to form side channel attacks (e.g. TAA) and chances are there
1898	  will be more of those attacks discovered in the future.
1899
1900	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1901	  might override this decision by tsx=on the command line parameter.
1902	  Even with TSX enabled, the kernel will attempt to enable the best
1903	  possible TAA mitigation setting depending on the microcode available
1904	  for the particular machine.
1905
1906	  This option allows to set the default tsx mode between tsx=on, =off
1907	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1908	  details.
1909
1910	  Say off if not sure, auto if TSX is in use but it should be used on safe
1911	  platforms or on if TSX is in use and the security aspect of tsx is not
1912	  relevant.
1913
1914config X86_INTEL_TSX_MODE_OFF
1915	bool "off"
1916	help
1917	  TSX is disabled if possible - equals to tsx=off command line parameter.
1918
1919config X86_INTEL_TSX_MODE_ON
1920	bool "on"
1921	help
1922	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1923	  line parameter.
1924
1925config X86_INTEL_TSX_MODE_AUTO
1926	bool "auto"
1927	help
1928	  TSX is enabled on TSX capable HW that is believed to be safe against
1929	  side channel attacks- equals the tsx=auto command line parameter.
1930endchoice
1931
1932config EFI
1933	bool "EFI runtime service support"
1934	depends on ACPI
1935	select UCS2_STRING
1936	select EFI_RUNTIME_WRAPPERS
1937	help
1938	  This enables the kernel to use EFI runtime services that are
1939	  available (such as the EFI variable services).
1940
1941	  This option is only useful on systems that have EFI firmware.
1942	  In addition, you should use the latest ELILO loader available
1943	  at <http://elilo.sourceforge.net> in order to take advantage
1944	  of EFI runtime services. However, even with this option, the
1945	  resultant kernel should continue to boot on existing non-EFI
1946	  platforms.
1947
1948config EFI_STUB
1949	bool "EFI stub support"
1950	depends on EFI && !X86_USE_3DNOW
1951	depends on $(cc-option,-mabi=ms) || X86_32
1952	select RELOCATABLE
1953	help
1954	  This kernel feature allows a bzImage to be loaded directly
1955	  by EFI firmware without the use of a bootloader.
1956
1957	  See Documentation/admin-guide/efi-stub.rst for more information.
1958
1959config EFI_MIXED
1960	bool "EFI mixed-mode support"
1961	depends on EFI_STUB && X86_64
1962	help
1963	   Enabling this feature allows a 64-bit kernel to be booted
1964	   on a 32-bit firmware, provided that your CPU supports 64-bit
1965	   mode.
1966
1967	   Note that it is not possible to boot a mixed-mode enabled
1968	   kernel via the EFI boot stub - a bootloader that supports
1969	   the EFI handover protocol must be used.
1970
1971	   If unsure, say N.
1972
1973source "kernel/Kconfig.hz"
1974
1975config KEXEC
1976	bool "kexec system call"
1977	select KEXEC_CORE
1978	help
1979	  kexec is a system call that implements the ability to shutdown your
1980	  current kernel, and to start another kernel.  It is like a reboot
1981	  but it is independent of the system firmware.   And like a reboot
1982	  you can start any kernel with it, not just Linux.
1983
1984	  The name comes from the similarity to the exec system call.
1985
1986	  It is an ongoing process to be certain the hardware in a machine
1987	  is properly shutdown, so do not be surprised if this code does not
1988	  initially work for you.  As of this writing the exact hardware
1989	  interface is strongly in flux, so no good recommendation can be
1990	  made.
1991
1992config KEXEC_FILE
1993	bool "kexec file based system call"
1994	select KEXEC_CORE
1995	select BUILD_BIN2C
1996	depends on X86_64
1997	depends on CRYPTO=y
1998	depends on CRYPTO_SHA256=y
1999	help
2000	  This is new version of kexec system call. This system call is
2001	  file based and takes file descriptors as system call argument
2002	  for kernel and initramfs as opposed to list of segments as
2003	  accepted by previous system call.
2004
2005config ARCH_HAS_KEXEC_PURGATORY
2006	def_bool KEXEC_FILE
2007
2008config KEXEC_SIG
2009	bool "Verify kernel signature during kexec_file_load() syscall"
2010	depends on KEXEC_FILE
2011	help
2012
2013	  This option makes the kexec_file_load() syscall check for a valid
2014	  signature of the kernel image.  The image can still be loaded without
2015	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2016	  there's a signature that we can check, then it must be valid.
2017
2018	  In addition to this option, you need to enable signature
2019	  verification for the corresponding kernel image type being
2020	  loaded in order for this to work.
2021
2022config KEXEC_SIG_FORCE
2023	bool "Require a valid signature in kexec_file_load() syscall"
2024	depends on KEXEC_SIG
2025	help
2026	  This option makes kernel signature verification mandatory for
2027	  the kexec_file_load() syscall.
2028
2029config KEXEC_BZIMAGE_VERIFY_SIG
2030	bool "Enable bzImage signature verification support"
2031	depends on KEXEC_SIG
2032	depends on SIGNED_PE_FILE_VERIFICATION
2033	select SYSTEM_TRUSTED_KEYRING
2034	help
2035	  Enable bzImage signature verification support.
2036
2037config CRASH_DUMP
2038	bool "kernel crash dumps"
2039	depends on X86_64 || (X86_32 && HIGHMEM)
2040	help
2041	  Generate crash dump after being started by kexec.
2042	  This should be normally only set in special crash dump kernels
2043	  which are loaded in the main kernel with kexec-tools into
2044	  a specially reserved region and then later executed after
2045	  a crash by kdump/kexec. The crash dump kernel must be compiled
2046	  to a memory address not used by the main kernel or BIOS using
2047	  PHYSICAL_START, or it must be built as a relocatable image
2048	  (CONFIG_RELOCATABLE=y).
2049	  For more details see Documentation/admin-guide/kdump/kdump.rst
2050
2051config KEXEC_JUMP
2052	bool "kexec jump"
2053	depends on KEXEC && HIBERNATION
2054	help
2055	  Jump between original kernel and kexeced kernel and invoke
2056	  code in physical address mode via KEXEC
2057
2058config PHYSICAL_START
2059	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2060	default "0x1000000"
2061	help
2062	  This gives the physical address where the kernel is loaded.
2063
2064	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2065	  bzImage will decompress itself to above physical address and
2066	  run from there. Otherwise, bzImage will run from the address where
2067	  it has been loaded by the boot loader and will ignore above physical
2068	  address.
2069
2070	  In normal kdump cases one does not have to set/change this option
2071	  as now bzImage can be compiled as a completely relocatable image
2072	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2073	  address. This option is mainly useful for the folks who don't want
2074	  to use a bzImage for capturing the crash dump and want to use a
2075	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2076	  to be specifically compiled to run from a specific memory area
2077	  (normally a reserved region) and this option comes handy.
2078
2079	  So if you are using bzImage for capturing the crash dump,
2080	  leave the value here unchanged to 0x1000000 and set
2081	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2082	  for capturing the crash dump change this value to start of
2083	  the reserved region.  In other words, it can be set based on
2084	  the "X" value as specified in the "crashkernel=YM@XM"
2085	  command line boot parameter passed to the panic-ed
2086	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2087	  for more details about crash dumps.
2088
2089	  Usage of bzImage for capturing the crash dump is recommended as
2090	  one does not have to build two kernels. Same kernel can be used
2091	  as production kernel and capture kernel. Above option should have
2092	  gone away after relocatable bzImage support is introduced. But it
2093	  is present because there are users out there who continue to use
2094	  vmlinux for dump capture. This option should go away down the
2095	  line.
2096
2097	  Don't change this unless you know what you are doing.
2098
2099config RELOCATABLE
2100	bool "Build a relocatable kernel"
2101	default y
2102	help
2103	  This builds a kernel image that retains relocation information
2104	  so it can be loaded someplace besides the default 1MB.
2105	  The relocations tend to make the kernel binary about 10% larger,
2106	  but are discarded at runtime.
2107
2108	  One use is for the kexec on panic case where the recovery kernel
2109	  must live at a different physical address than the primary
2110	  kernel.
2111
2112	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2113	  it has been loaded at and the compile time physical address
2114	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2115
2116config RANDOMIZE_BASE
2117	bool "Randomize the address of the kernel image (KASLR)"
2118	depends on RELOCATABLE
2119	default y
2120	help
2121	  In support of Kernel Address Space Layout Randomization (KASLR),
2122	  this randomizes the physical address at which the kernel image
2123	  is decompressed and the virtual address where the kernel
2124	  image is mapped, as a security feature that deters exploit
2125	  attempts relying on knowledge of the location of kernel
2126	  code internals.
2127
2128	  On 64-bit, the kernel physical and virtual addresses are
2129	  randomized separately. The physical address will be anywhere
2130	  between 16MB and the top of physical memory (up to 64TB). The
2131	  virtual address will be randomized from 16MB up to 1GB (9 bits
2132	  of entropy). Note that this also reduces the memory space
2133	  available to kernel modules from 1.5GB to 1GB.
2134
2135	  On 32-bit, the kernel physical and virtual addresses are
2136	  randomized together. They will be randomized from 16MB up to
2137	  512MB (8 bits of entropy).
2138
2139	  Entropy is generated using the RDRAND instruction if it is
2140	  supported. If RDTSC is supported, its value is mixed into
2141	  the entropy pool as well. If neither RDRAND nor RDTSC are
2142	  supported, then entropy is read from the i8254 timer. The
2143	  usable entropy is limited by the kernel being built using
2144	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2145	  minimum of 2MB. As a result, only 10 bits of entropy are
2146	  theoretically possible, but the implementations are further
2147	  limited due to memory layouts.
2148
2149	  If unsure, say Y.
2150
2151# Relocation on x86 needs some additional build support
2152config X86_NEED_RELOCS
2153	def_bool y
2154	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2155
2156config PHYSICAL_ALIGN
2157	hex "Alignment value to which kernel should be aligned"
2158	default "0x200000"
2159	range 0x2000 0x1000000 if X86_32
2160	range 0x200000 0x1000000 if X86_64
2161	help
2162	  This value puts the alignment restrictions on physical address
2163	  where kernel is loaded and run from. Kernel is compiled for an
2164	  address which meets above alignment restriction.
2165
2166	  If bootloader loads the kernel at a non-aligned address and
2167	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2168	  address aligned to above value and run from there.
2169
2170	  If bootloader loads the kernel at a non-aligned address and
2171	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2172	  load address and decompress itself to the address it has been
2173	  compiled for and run from there. The address for which kernel is
2174	  compiled already meets above alignment restrictions. Hence the
2175	  end result is that kernel runs from a physical address meeting
2176	  above alignment restrictions.
2177
2178	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2179	  this value must be a multiple of 0x200000.
2180
2181	  Don't change this unless you know what you are doing.
2182
2183config DYNAMIC_MEMORY_LAYOUT
2184	bool
2185	help
2186	  This option makes base addresses of vmalloc and vmemmap as well as
2187	  __PAGE_OFFSET movable during boot.
2188
2189config RANDOMIZE_MEMORY
2190	bool "Randomize the kernel memory sections"
2191	depends on X86_64
2192	depends on RANDOMIZE_BASE
2193	select DYNAMIC_MEMORY_LAYOUT
2194	default RANDOMIZE_BASE
2195	help
2196	   Randomizes the base virtual address of kernel memory sections
2197	   (physical memory mapping, vmalloc & vmemmap). This security feature
2198	   makes exploits relying on predictable memory locations less reliable.
2199
2200	   The order of allocations remains unchanged. Entropy is generated in
2201	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2202	   configuration have in average 30,000 different possible virtual
2203	   addresses for each memory section.
2204
2205	   If unsure, say Y.
2206
2207config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2208	hex "Physical memory mapping padding" if EXPERT
2209	depends on RANDOMIZE_MEMORY
2210	default "0xa" if MEMORY_HOTPLUG
2211	default "0x0"
2212	range 0x1 0x40 if MEMORY_HOTPLUG
2213	range 0x0 0x40
2214	help
2215	   Define the padding in terabytes added to the existing physical
2216	   memory size during kernel memory randomization. It is useful
2217	   for memory hotplug support but reduces the entropy available for
2218	   address randomization.
2219
2220	   If unsure, leave at the default value.
2221
2222config HOTPLUG_CPU
2223	def_bool y
2224	depends on SMP
2225
2226config BOOTPARAM_HOTPLUG_CPU0
2227	bool "Set default setting of cpu0_hotpluggable"
2228	depends on HOTPLUG_CPU
2229	help
2230	  Set whether default state of cpu0_hotpluggable is on or off.
2231
2232	  Say Y here to enable CPU0 hotplug by default. If this switch
2233	  is turned on, there is no need to give cpu0_hotplug kernel
2234	  parameter and the CPU0 hotplug feature is enabled by default.
2235
2236	  Please note: there are two known CPU0 dependencies if you want
2237	  to enable the CPU0 hotplug feature either by this switch or by
2238	  cpu0_hotplug kernel parameter.
2239
2240	  First, resume from hibernate or suspend always starts from CPU0.
2241	  So hibernate and suspend are prevented if CPU0 is offline.
2242
2243	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2244	  offline if any interrupt can not migrate out of CPU0. There may
2245	  be other CPU0 dependencies.
2246
2247	  Please make sure the dependencies are under your control before
2248	  you enable this feature.
2249
2250	  Say N if you don't want to enable CPU0 hotplug feature by default.
2251	  You still can enable the CPU0 hotplug feature at boot by kernel
2252	  parameter cpu0_hotplug.
2253
2254config DEBUG_HOTPLUG_CPU0
2255	def_bool n
2256	prompt "Debug CPU0 hotplug"
2257	depends on HOTPLUG_CPU
2258	help
2259	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2260	  soon as possible and boots up userspace with CPU0 offlined. User
2261	  can online CPU0 back after boot time.
2262
2263	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2264	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2265	  compilation or giving cpu0_hotplug kernel parameter at boot.
2266
2267	  If unsure, say N.
2268
2269config COMPAT_VDSO
2270	def_bool n
2271	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2272	depends on COMPAT_32
2273	help
2274	  Certain buggy versions of glibc will crash if they are
2275	  presented with a 32-bit vDSO that is not mapped at the address
2276	  indicated in its segment table.
2277
2278	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2279	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2280	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2281	  the only released version with the bug, but OpenSUSE 9
2282	  contains a buggy "glibc 2.3.2".
2283
2284	  The symptom of the bug is that everything crashes on startup, saying:
2285	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2286
2287	  Saying Y here changes the default value of the vdso32 boot
2288	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2289	  This works around the glibc bug but hurts performance.
2290
2291	  If unsure, say N: if you are compiling your own kernel, you
2292	  are unlikely to be using a buggy version of glibc.
2293
2294choice
2295	prompt "vsyscall table for legacy applications"
2296	depends on X86_64
2297	default LEGACY_VSYSCALL_XONLY
2298	help
2299	  Legacy user code that does not know how to find the vDSO expects
2300	  to be able to issue three syscalls by calling fixed addresses in
2301	  kernel space. Since this location is not randomized with ASLR,
2302	  it can be used to assist security vulnerability exploitation.
2303
2304	  This setting can be changed at boot time via the kernel command
2305	  line parameter vsyscall=[emulate|xonly|none].
2306
2307	  On a system with recent enough glibc (2.14 or newer) and no
2308	  static binaries, you can say None without a performance penalty
2309	  to improve security.
2310
2311	  If unsure, select "Emulate execution only".
2312
2313	config LEGACY_VSYSCALL_EMULATE
2314		bool "Full emulation"
2315		help
2316		  The kernel traps and emulates calls into the fixed vsyscall
2317		  address mapping. This makes the mapping non-executable, but
2318		  it still contains readable known contents, which could be
2319		  used in certain rare security vulnerability exploits. This
2320		  configuration is recommended when using legacy userspace
2321		  that still uses vsyscalls along with legacy binary
2322		  instrumentation tools that require code to be readable.
2323
2324		  An example of this type of legacy userspace is running
2325		  Pin on an old binary that still uses vsyscalls.
2326
2327	config LEGACY_VSYSCALL_XONLY
2328		bool "Emulate execution only"
2329		help
2330		  The kernel traps and emulates calls into the fixed vsyscall
2331		  address mapping and does not allow reads.  This
2332		  configuration is recommended when userspace might use the
2333		  legacy vsyscall area but support for legacy binary
2334		  instrumentation of legacy code is not needed.  It mitigates
2335		  certain uses of the vsyscall area as an ASLR-bypassing
2336		  buffer.
2337
2338	config LEGACY_VSYSCALL_NONE
2339		bool "None"
2340		help
2341		  There will be no vsyscall mapping at all. This will
2342		  eliminate any risk of ASLR bypass due to the vsyscall
2343		  fixed address mapping. Attempts to use the vsyscalls
2344		  will be reported to dmesg, so that either old or
2345		  malicious userspace programs can be identified.
2346
2347endchoice
2348
2349config CMDLINE_BOOL
2350	bool "Built-in kernel command line"
2351	help
2352	  Allow for specifying boot arguments to the kernel at
2353	  build time.  On some systems (e.g. embedded ones), it is
2354	  necessary or convenient to provide some or all of the
2355	  kernel boot arguments with the kernel itself (that is,
2356	  to not rely on the boot loader to provide them.)
2357
2358	  To compile command line arguments into the kernel,
2359	  set this option to 'Y', then fill in the
2360	  boot arguments in CONFIG_CMDLINE.
2361
2362	  Systems with fully functional boot loaders (i.e. non-embedded)
2363	  should leave this option set to 'N'.
2364
2365config CMDLINE
2366	string "Built-in kernel command string"
2367	depends on CMDLINE_BOOL
2368	default ""
2369	help
2370	  Enter arguments here that should be compiled into the kernel
2371	  image and used at boot time.  If the boot loader provides a
2372	  command line at boot time, it is appended to this string to
2373	  form the full kernel command line, when the system boots.
2374
2375	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2376	  change this behavior.
2377
2378	  In most cases, the command line (whether built-in or provided
2379	  by the boot loader) should specify the device for the root
2380	  file system.
2381
2382config CMDLINE_OVERRIDE
2383	bool "Built-in command line overrides boot loader arguments"
2384	depends on CMDLINE_BOOL && CMDLINE != ""
2385	help
2386	  Set this option to 'Y' to have the kernel ignore the boot loader
2387	  command line, and use ONLY the built-in command line.
2388
2389	  This is used to work around broken boot loaders.  This should
2390	  be set to 'N' under normal conditions.
2391
2392config MODIFY_LDT_SYSCALL
2393	bool "Enable the LDT (local descriptor table)" if EXPERT
2394	default y
2395	help
2396	  Linux can allow user programs to install a per-process x86
2397	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2398	  call.  This is required to run 16-bit or segmented code such as
2399	  DOSEMU or some Wine programs.  It is also used by some very old
2400	  threading libraries.
2401
2402	  Enabling this feature adds a small amount of overhead to
2403	  context switches and increases the low-level kernel attack
2404	  surface.  Disabling it removes the modify_ldt(2) system call.
2405
2406	  Saying 'N' here may make sense for embedded or server kernels.
2407
2408source "kernel/livepatch/Kconfig"
2409
2410endmenu
2411
2412config ARCH_HAS_ADD_PAGES
2413	def_bool y
2414	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2415
2416config ARCH_ENABLE_MEMORY_HOTPLUG
2417	def_bool y
2418	depends on X86_64 || (X86_32 && HIGHMEM)
2419
2420config ARCH_ENABLE_MEMORY_HOTREMOVE
2421	def_bool y
2422	depends on MEMORY_HOTPLUG
2423
2424config USE_PERCPU_NUMA_NODE_ID
2425	def_bool y
2426	depends on NUMA
2427
2428config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2429	def_bool y
2430	depends on X86_64 || X86_PAE
2431
2432config ARCH_ENABLE_HUGEPAGE_MIGRATION
2433	def_bool y
2434	depends on X86_64 && HUGETLB_PAGE && MIGRATION
2435
2436config ARCH_ENABLE_THP_MIGRATION
2437	def_bool y
2438	depends on X86_64 && TRANSPARENT_HUGEPAGE
2439
2440menu "Power management and ACPI options"
2441
2442config ARCH_HIBERNATION_HEADER
2443	def_bool y
2444	depends on HIBERNATION
2445
2446source "kernel/power/Kconfig"
2447
2448source "drivers/acpi/Kconfig"
2449
2450source "drivers/sfi/Kconfig"
2451
2452config X86_APM_BOOT
2453	def_bool y
2454	depends on APM
2455
2456menuconfig APM
2457	tristate "APM (Advanced Power Management) BIOS support"
2458	depends on X86_32 && PM_SLEEP
2459	help
2460	  APM is a BIOS specification for saving power using several different
2461	  techniques. This is mostly useful for battery powered laptops with
2462	  APM compliant BIOSes. If you say Y here, the system time will be
2463	  reset after a RESUME operation, the /proc/apm device will provide
2464	  battery status information, and user-space programs will receive
2465	  notification of APM "events" (e.g. battery status change).
2466
2467	  If you select "Y" here, you can disable actual use of the APM
2468	  BIOS by passing the "apm=off" option to the kernel at boot time.
2469
2470	  Note that the APM support is almost completely disabled for
2471	  machines with more than one CPU.
2472
2473	  In order to use APM, you will need supporting software. For location
2474	  and more information, read <file:Documentation/power/apm-acpi.rst>
2475	  and the Battery Powered Linux mini-HOWTO, available from
2476	  <http://www.tldp.org/docs.html#howto>.
2477
2478	  This driver does not spin down disk drives (see the hdparm(8)
2479	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2480	  VESA-compliant "green" monitors.
2481
2482	  This driver does not support the TI 4000M TravelMate and the ACER
2483	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2484	  desktop machines also don't have compliant BIOSes, and this driver
2485	  may cause those machines to panic during the boot phase.
2486
2487	  Generally, if you don't have a battery in your machine, there isn't
2488	  much point in using this driver and you should say N. If you get
2489	  random kernel OOPSes or reboots that don't seem to be related to
2490	  anything, try disabling/enabling this option (or disabling/enabling
2491	  APM in your BIOS).
2492
2493	  Some other things you should try when experiencing seemingly random,
2494	  "weird" problems:
2495
2496	  1) make sure that you have enough swap space and that it is
2497	  enabled.
2498	  2) pass the "no-hlt" option to the kernel
2499	  3) switch on floating point emulation in the kernel and pass
2500	  the "no387" option to the kernel
2501	  4) pass the "floppy=nodma" option to the kernel
2502	  5) pass the "mem=4M" option to the kernel (thereby disabling
2503	  all but the first 4 MB of RAM)
2504	  6) make sure that the CPU is not over clocked.
2505	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2506	  8) disable the cache from your BIOS settings
2507	  9) install a fan for the video card or exchange video RAM
2508	  10) install a better fan for the CPU
2509	  11) exchange RAM chips
2510	  12) exchange the motherboard.
2511
2512	  To compile this driver as a module, choose M here: the
2513	  module will be called apm.
2514
2515if APM
2516
2517config APM_IGNORE_USER_SUSPEND
2518	bool "Ignore USER SUSPEND"
2519	help
2520	  This option will ignore USER SUSPEND requests. On machines with a
2521	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2522	  series notebooks, it is necessary to say Y because of a BIOS bug.
2523
2524config APM_DO_ENABLE
2525	bool "Enable PM at boot time"
2526	help
2527	  Enable APM features at boot time. From page 36 of the APM BIOS
2528	  specification: "When disabled, the APM BIOS does not automatically
2529	  power manage devices, enter the Standby State, enter the Suspend
2530	  State, or take power saving steps in response to CPU Idle calls."
2531	  This driver will make CPU Idle calls when Linux is idle (unless this
2532	  feature is turned off -- see "Do CPU IDLE calls", below). This
2533	  should always save battery power, but more complicated APM features
2534	  will be dependent on your BIOS implementation. You may need to turn
2535	  this option off if your computer hangs at boot time when using APM
2536	  support, or if it beeps continuously instead of suspending. Turn
2537	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2538	  T400CDT. This is off by default since most machines do fine without
2539	  this feature.
2540
2541config APM_CPU_IDLE
2542	depends on CPU_IDLE
2543	bool "Make CPU Idle calls when idle"
2544	help
2545	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2546	  On some machines, this can activate improved power savings, such as
2547	  a slowed CPU clock rate, when the machine is idle. These idle calls
2548	  are made after the idle loop has run for some length of time (e.g.,
2549	  333 mS). On some machines, this will cause a hang at boot time or
2550	  whenever the CPU becomes idle. (On machines with more than one CPU,
2551	  this option does nothing.)
2552
2553config APM_DISPLAY_BLANK
2554	bool "Enable console blanking using APM"
2555	help
2556	  Enable console blanking using the APM. Some laptops can use this to
2557	  turn off the LCD backlight when the screen blanker of the Linux
2558	  virtual console blanks the screen. Note that this is only used by
2559	  the virtual console screen blanker, and won't turn off the backlight
2560	  when using the X Window system. This also doesn't have anything to
2561	  do with your VESA-compliant power-saving monitor. Further, this
2562	  option doesn't work for all laptops -- it might not turn off your
2563	  backlight at all, or it might print a lot of errors to the console,
2564	  especially if you are using gpm.
2565
2566config APM_ALLOW_INTS
2567	bool "Allow interrupts during APM BIOS calls"
2568	help
2569	  Normally we disable external interrupts while we are making calls to
2570	  the APM BIOS as a measure to lessen the effects of a badly behaving
2571	  BIOS implementation.  The BIOS should reenable interrupts if it
2572	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2573	  many of the newer IBM Thinkpads.  If you experience hangs when you
2574	  suspend, try setting this to Y.  Otherwise, say N.
2575
2576endif # APM
2577
2578source "drivers/cpufreq/Kconfig"
2579
2580source "drivers/cpuidle/Kconfig"
2581
2582source "drivers/idle/Kconfig"
2583
2584endmenu
2585
2586
2587menu "Bus options (PCI etc.)"
2588
2589choice
2590	prompt "PCI access mode"
2591	depends on X86_32 && PCI
2592	default PCI_GOANY
2593	help
2594	  On PCI systems, the BIOS can be used to detect the PCI devices and
2595	  determine their configuration. However, some old PCI motherboards
2596	  have BIOS bugs and may crash if this is done. Also, some embedded
2597	  PCI-based systems don't have any BIOS at all. Linux can also try to
2598	  detect the PCI hardware directly without using the BIOS.
2599
2600	  With this option, you can specify how Linux should detect the
2601	  PCI devices. If you choose "BIOS", the BIOS will be used,
2602	  if you choose "Direct", the BIOS won't be used, and if you
2603	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2604	  If you choose "Any", the kernel will try MMCONFIG, then the
2605	  direct access method and falls back to the BIOS if that doesn't
2606	  work. If unsure, go with the default, which is "Any".
2607
2608config PCI_GOBIOS
2609	bool "BIOS"
2610
2611config PCI_GOMMCONFIG
2612	bool "MMConfig"
2613
2614config PCI_GODIRECT
2615	bool "Direct"
2616
2617config PCI_GOOLPC
2618	bool "OLPC XO-1"
2619	depends on OLPC
2620
2621config PCI_GOANY
2622	bool "Any"
2623
2624endchoice
2625
2626config PCI_BIOS
2627	def_bool y
2628	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2629
2630# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2631config PCI_DIRECT
2632	def_bool y
2633	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2634
2635config PCI_MMCONFIG
2636	bool "Support mmconfig PCI config space access" if X86_64
2637	default y
2638	depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2639	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2640
2641config PCI_OLPC
2642	def_bool y
2643	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2644
2645config PCI_XEN
2646	def_bool y
2647	depends on PCI && XEN
2648	select SWIOTLB_XEN
2649
2650config MMCONF_FAM10H
2651	def_bool y
2652	depends on X86_64 && PCI_MMCONFIG && ACPI
2653
2654config PCI_CNB20LE_QUIRK
2655	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2656	depends on PCI
2657	help
2658	  Read the PCI windows out of the CNB20LE host bridge. This allows
2659	  PCI hotplug to work on systems with the CNB20LE chipset which do
2660	  not have ACPI.
2661
2662	  There's no public spec for this chipset, and this functionality
2663	  is known to be incomplete.
2664
2665	  You should say N unless you know you need this.
2666
2667config ISA_BUS
2668	bool "ISA bus support on modern systems" if EXPERT
2669	help
2670	  Expose ISA bus device drivers and options available for selection and
2671	  configuration. Enable this option if your target machine has an ISA
2672	  bus. ISA is an older system, displaced by PCI and newer bus
2673	  architectures -- if your target machine is modern, it probably does
2674	  not have an ISA bus.
2675
2676	  If unsure, say N.
2677
2678# x86_64 have no ISA slots, but can have ISA-style DMA.
2679config ISA_DMA_API
2680	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2681	default y
2682	help
2683	  Enables ISA-style DMA support for devices requiring such controllers.
2684	  If unsure, say Y.
2685
2686if X86_32
2687
2688config ISA
2689	bool "ISA support"
2690	help
2691	  Find out whether you have ISA slots on your motherboard.  ISA is the
2692	  name of a bus system, i.e. the way the CPU talks to the other stuff
2693	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2694	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2695	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2696
2697config SCx200
2698	tristate "NatSemi SCx200 support"
2699	help
2700	  This provides basic support for National Semiconductor's
2701	  (now AMD's) Geode processors.  The driver probes for the
2702	  PCI-IDs of several on-chip devices, so its a good dependency
2703	  for other scx200_* drivers.
2704
2705	  If compiled as a module, the driver is named scx200.
2706
2707config SCx200HR_TIMER
2708	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2709	depends on SCx200
2710	default y
2711	help
2712	  This driver provides a clocksource built upon the on-chip
2713	  27MHz high-resolution timer.  Its also a workaround for
2714	  NSC Geode SC-1100's buggy TSC, which loses time when the
2715	  processor goes idle (as is done by the scheduler).  The
2716	  other workaround is idle=poll boot option.
2717
2718config OLPC
2719	bool "One Laptop Per Child support"
2720	depends on !X86_PAE
2721	select GPIOLIB
2722	select OF
2723	select OF_PROMTREE
2724	select IRQ_DOMAIN
2725	select OLPC_EC
2726	help
2727	  Add support for detecting the unique features of the OLPC
2728	  XO hardware.
2729
2730config OLPC_XO1_PM
2731	bool "OLPC XO-1 Power Management"
2732	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2733	help
2734	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2735
2736config OLPC_XO1_RTC
2737	bool "OLPC XO-1 Real Time Clock"
2738	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2739	help
2740	  Add support for the XO-1 real time clock, which can be used as a
2741	  programmable wakeup source.
2742
2743config OLPC_XO1_SCI
2744	bool "OLPC XO-1 SCI extras"
2745	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2746	depends on INPUT=y
2747	select POWER_SUPPLY
2748	help
2749	  Add support for SCI-based features of the OLPC XO-1 laptop:
2750	   - EC-driven system wakeups
2751	   - Power button
2752	   - Ebook switch
2753	   - Lid switch
2754	   - AC adapter status updates
2755	   - Battery status updates
2756
2757config OLPC_XO15_SCI
2758	bool "OLPC XO-1.5 SCI extras"
2759	depends on OLPC && ACPI
2760	select POWER_SUPPLY
2761	help
2762	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2763	   - EC-driven system wakeups
2764	   - AC adapter status updates
2765	   - Battery status updates
2766
2767config ALIX
2768	bool "PCEngines ALIX System Support (LED setup)"
2769	select GPIOLIB
2770	help
2771	  This option enables system support for the PCEngines ALIX.
2772	  At present this just sets up LEDs for GPIO control on
2773	  ALIX2/3/6 boards.  However, other system specific setup should
2774	  get added here.
2775
2776	  Note: You must still enable the drivers for GPIO and LED support
2777	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2778
2779	  Note: You have to set alix.force=1 for boards with Award BIOS.
2780
2781config NET5501
2782	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2783	select GPIOLIB
2784	help
2785	  This option enables system support for the Soekris Engineering net5501.
2786
2787config GEOS
2788	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2789	select GPIOLIB
2790	depends on DMI
2791	help
2792	  This option enables system support for the Traverse Technologies GEOS.
2793
2794config TS5500
2795	bool "Technologic Systems TS-5500 platform support"
2796	depends on MELAN
2797	select CHECK_SIGNATURE
2798	select NEW_LEDS
2799	select LEDS_CLASS
2800	help
2801	  This option enables system support for the Technologic Systems TS-5500.
2802
2803endif # X86_32
2804
2805config AMD_NB
2806	def_bool y
2807	depends on CPU_SUP_AMD && PCI
2808
2809config X86_SYSFB
2810	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2811	help
2812	  Firmwares often provide initial graphics framebuffers so the BIOS,
2813	  bootloader or kernel can show basic video-output during boot for
2814	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2815	  Extensions and EFI-framebuffers for this, which are mostly limited
2816	  to x86.
2817	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2818	  framebuffers so the new generic system-framebuffer drivers can be
2819	  used on x86. If the framebuffer is not compatible with the generic
2820	  modes, it is advertised as fallback platform framebuffer so legacy
2821	  drivers like efifb, vesafb and uvesafb can pick it up.
2822	  If this option is not selected, all system framebuffers are always
2823	  marked as fallback platform framebuffers as usual.
2824
2825	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2826	  not be able to pick up generic system framebuffers if this option
2827	  is selected. You are highly encouraged to enable simplefb as
2828	  replacement if you select this option. simplefb can correctly deal
2829	  with generic system framebuffers. But you should still keep vesafb
2830	  and others enabled as fallback if a system framebuffer is
2831	  incompatible with simplefb.
2832
2833	  If unsure, say Y.
2834
2835endmenu
2836
2837
2838menu "Binary Emulations"
2839
2840config IA32_EMULATION
2841	bool "IA32 Emulation"
2842	depends on X86_64
2843	select ARCH_WANT_OLD_COMPAT_IPC
2844	select BINFMT_ELF
2845	select COMPAT_BINFMT_ELF
2846	select COMPAT_OLD_SIGACTION
2847	help
2848	  Include code to run legacy 32-bit programs under a
2849	  64-bit kernel. You should likely turn this on, unless you're
2850	  100% sure that you don't have any 32-bit programs left.
2851
2852config IA32_AOUT
2853	tristate "IA32 a.out support"
2854	depends on IA32_EMULATION
2855	depends on BROKEN
2856	help
2857	  Support old a.out binaries in the 32bit emulation.
2858
2859config X86_X32
2860	bool "x32 ABI for 64-bit mode"
2861	depends on X86_64
2862	help
2863	  Include code to run binaries for the x32 native 32-bit ABI
2864	  for 64-bit processors.  An x32 process gets access to the
2865	  full 64-bit register file and wide data path while leaving
2866	  pointers at 32 bits for smaller memory footprint.
2867
2868	  You will need a recent binutils (2.22 or later) with
2869	  elf32_x86_64 support enabled to compile a kernel with this
2870	  option set.
2871
2872config COMPAT_32
2873	def_bool y
2874	depends on IA32_EMULATION || X86_32
2875	select HAVE_UID16
2876	select OLD_SIGSUSPEND3
2877
2878config COMPAT
2879	def_bool y
2880	depends on IA32_EMULATION || X86_X32
2881
2882if COMPAT
2883config COMPAT_FOR_U64_ALIGNMENT
2884	def_bool y
2885
2886config SYSVIPC_COMPAT
2887	def_bool y
2888	depends on SYSVIPC
2889endif
2890
2891endmenu
2892
2893
2894config HAVE_ATOMIC_IOMAP
2895	def_bool y
2896	depends on X86_32
2897
2898source "drivers/firmware/Kconfig"
2899
2900source "arch/x86/kvm/Kconfig"
2901
2902source "arch/x86/Kconfig.assembler"
2903