xref: /openbmc/linux/arch/x86/Kconfig (revision a16be368)
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
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_UACCESS_MCSAFE		if X86_64 && X86_MCE
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
112	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
113	select GENERIC_CLOCKEVENTS_MIN_ADJUST
114	select GENERIC_CMOS_UPDATE
115	select GENERIC_CPU_AUTOPROBE
116	select GENERIC_CPU_VULNERABILITIES
117	select GENERIC_EARLY_IOREMAP
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_COPY_THREAD_TLS
165	select HAVE_C_RECORDMCOUNT
166	select HAVE_DEBUG_KMEMLEAK
167	select HAVE_DMA_CONTIGUOUS
168	select HAVE_DYNAMIC_FTRACE
169	select HAVE_DYNAMIC_FTRACE_WITH_REGS
170	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
171	select HAVE_EBPF_JIT
172	select HAVE_EFFICIENT_UNALIGNED_ACCESS
173	select HAVE_EISA
174	select HAVE_EXIT_THREAD
175	select HAVE_FAST_GUP
176	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
177	select HAVE_FTRACE_MCOUNT_RECORD
178	select HAVE_FUNCTION_GRAPH_TRACER
179	select HAVE_FUNCTION_TRACER
180	select HAVE_GCC_PLUGINS
181	select HAVE_HW_BREAKPOINT
182	select HAVE_IDE
183	select HAVE_IOREMAP_PROT
184	select HAVE_IRQ_TIME_ACCOUNTING
185	select HAVE_KERNEL_BZIP2
186	select HAVE_KERNEL_GZIP
187	select HAVE_KERNEL_LZ4
188	select HAVE_KERNEL_LZMA
189	select HAVE_KERNEL_LZO
190	select HAVE_KERNEL_XZ
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_REGS_AND_STACK_ACCESS_API
212	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
213	select HAVE_FUNCTION_ARG_ACCESS_API
214	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
215	select HAVE_STACK_VALIDATION		if X86_64
216	select HAVE_RSEQ
217	select HAVE_SYSCALL_TRACEPOINTS
218	select HAVE_UNSTABLE_SCHED_CLOCK
219	select HAVE_USER_RETURN_NOTIFIER
220	select HAVE_GENERIC_VDSO
221	select HOTPLUG_SMT			if SMP
222	select IRQ_FORCED_THREADING
223	select NEED_SG_DMA_LENGTH
224	select PCI_DOMAINS			if PCI
225	select PCI_LOCKLESS_CONFIG		if PCI
226	select PERF_EVENTS
227	select RTC_LIB
228	select RTC_MC146818_LIB
229	select SPARSE_IRQ
230	select SRCU
231	select SYSCTL_EXCEPTION_TRACE
232	select THREAD_INFO_IN_TASK
233	select USER_STACKTRACE_SUPPORT
234	select VIRT_TO_BUS
235	select X86_FEATURE_NAMES		if PROC_FS
236	select PROC_PID_ARCH_STATUS		if PROC_FS
237	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
238
239config INSTRUCTION_DECODER
240	def_bool y
241	depends on KPROBES || PERF_EVENTS || UPROBES
242
243config OUTPUT_FORMAT
244	string
245	default "elf32-i386" if X86_32
246	default "elf64-x86-64" if X86_64
247
248config LOCKDEP_SUPPORT
249	def_bool y
250
251config STACKTRACE_SUPPORT
252	def_bool y
253
254config MMU
255	def_bool y
256
257config ARCH_MMAP_RND_BITS_MIN
258	default 28 if 64BIT
259	default 8
260
261config ARCH_MMAP_RND_BITS_MAX
262	default 32 if 64BIT
263	default 16
264
265config ARCH_MMAP_RND_COMPAT_BITS_MIN
266	default 8
267
268config ARCH_MMAP_RND_COMPAT_BITS_MAX
269	default 16
270
271config SBUS
272	bool
273
274config GENERIC_ISA_DMA
275	def_bool y
276	depends on ISA_DMA_API
277
278config GENERIC_BUG
279	def_bool y
280	depends on BUG
281	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
282
283config GENERIC_BUG_RELATIVE_POINTERS
284	bool
285
286config ARCH_MAY_HAVE_PC_FDC
287	def_bool y
288	depends on ISA_DMA_API
289
290config GENERIC_CALIBRATE_DELAY
291	def_bool y
292
293config ARCH_HAS_CPU_RELAX
294	def_bool y
295
296config ARCH_HAS_CACHE_LINE_SIZE
297	def_bool y
298
299config ARCH_HAS_FILTER_PGPROT
300	def_bool y
301
302config HAVE_SETUP_PER_CPU_AREA
303	def_bool y
304
305config NEED_PER_CPU_EMBED_FIRST_CHUNK
306	def_bool y
307
308config NEED_PER_CPU_PAGE_FIRST_CHUNK
309	def_bool y
310
311config ARCH_HIBERNATION_POSSIBLE
312	def_bool y
313
314config ARCH_SUSPEND_POSSIBLE
315	def_bool y
316
317config ARCH_WANT_GENERAL_HUGETLB
318	def_bool y
319
320config ZONE_DMA32
321	def_bool y if X86_64
322
323config AUDIT_ARCH
324	def_bool y if X86_64
325
326config ARCH_SUPPORTS_DEBUG_PAGEALLOC
327	def_bool y
328
329config KASAN_SHADOW_OFFSET
330	hex
331	depends on KASAN
332	default 0xdffffc0000000000
333
334config HAVE_INTEL_TXT
335	def_bool y
336	depends on INTEL_IOMMU && ACPI
337
338config X86_32_SMP
339	def_bool y
340	depends on X86_32 && SMP
341
342config X86_64_SMP
343	def_bool y
344	depends on X86_64 && SMP
345
346config X86_32_LAZY_GS
347	def_bool y
348	depends on X86_32 && !STACKPROTECTOR
349
350config ARCH_SUPPORTS_UPROBES
351	def_bool y
352
353config FIX_EARLYCON_MEM
354	def_bool y
355
356config DYNAMIC_PHYSICAL_MASK
357	bool
358
359config PGTABLE_LEVELS
360	int
361	default 5 if X86_5LEVEL
362	default 4 if X86_64
363	default 3 if X86_PAE
364	default 2
365
366config CC_HAS_SANE_STACKPROTECTOR
367	bool
368	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
369	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
370	help
371	   We have to make sure stack protector is unconditionally disabled if
372	   the compiler produces broken code.
373
374menu "Processor type and features"
375
376config ZONE_DMA
377	bool "DMA memory allocation support" if EXPERT
378	default y
379	help
380	  DMA memory allocation support allows devices with less than 32-bit
381	  addressing to allocate within the first 16MB of address space.
382	  Disable if no such devices will be used.
383
384	  If unsure, say Y.
385
386config SMP
387	bool "Symmetric multi-processing support"
388	---help---
389	  This enables support for systems with more than one CPU. If you have
390	  a system with only one CPU, say N. If you have a system with more
391	  than one CPU, say Y.
392
393	  If you say N here, the kernel will run on uni- and multiprocessor
394	  machines, but will use only one CPU of a multiprocessor machine. If
395	  you say Y here, the kernel will run on many, but not all,
396	  uniprocessor machines. On a uniprocessor machine, the kernel
397	  will run faster if you say N here.
398
399	  Note that if you say Y here and choose architecture "586" or
400	  "Pentium" under "Processor family", the kernel will not work on 486
401	  architectures. Similarly, multiprocessor kernels for the "PPro"
402	  architecture may not work on all Pentium based boards.
403
404	  People using multiprocessor machines who say Y here should also say
405	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
406	  Management" code will be disabled if you say Y here.
407
408	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
409	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
410	  <http://www.tldp.org/docs.html#howto>.
411
412	  If you don't know what to do here, say N.
413
414config X86_FEATURE_NAMES
415	bool "Processor feature human-readable names" if EMBEDDED
416	default y
417	---help---
418	  This option compiles in a table of x86 feature bits and corresponding
419	  names.  This is required to support /proc/cpuinfo and a few kernel
420	  messages.  You can disable this to save space, at the expense of
421	  making those few kernel messages show numeric feature bits instead.
422
423	  If in doubt, say Y.
424
425config X86_X2APIC
426	bool "Support x2apic"
427	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
428	---help---
429	  This enables x2apic support on CPUs that have this feature.
430
431	  This allows 32-bit apic IDs (so it can support very large systems),
432	  and accesses the local apic via MSRs not via mmio.
433
434	  If you don't know what to do here, say N.
435
436config X86_MPPARSE
437	bool "Enable MPS table" if ACPI || SFI
438	default y
439	depends on X86_LOCAL_APIC
440	---help---
441	  For old smp systems that do not have proper acpi support. Newer systems
442	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
443
444config GOLDFISH
445	def_bool y
446	depends on X86_GOLDFISH
447
448config RETPOLINE
449	bool "Avoid speculative indirect branches in kernel"
450	default y
451	select STACK_VALIDATION if HAVE_STACK_VALIDATION
452	help
453	  Compile kernel with the retpoline compiler options to guard against
454	  kernel-to-user data leaks by avoiding speculative indirect
455	  branches. Requires a compiler with -mindirect-branch=thunk-extern
456	  support for full protection. The kernel may run slower.
457
458config X86_CPU_RESCTRL
459	bool "x86 CPU resource control support"
460	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
461	select KERNFS
462	select PROC_CPU_RESCTRL		if PROC_FS
463	help
464	  Enable x86 CPU resource control support.
465
466	  Provide support for the allocation and monitoring of system resources
467	  usage by the CPU.
468
469	  Intel calls this Intel Resource Director Technology
470	  (Intel(R) RDT). More information about RDT can be found in the
471	  Intel x86 Architecture Software Developer Manual.
472
473	  AMD calls this AMD Platform Quality of Service (AMD QoS).
474	  More information about AMD QoS can be found in the AMD64 Technology
475	  Platform Quality of Service Extensions manual.
476
477	  Say N if unsure.
478
479if X86_32
480config X86_BIGSMP
481	bool "Support for big SMP systems with more than 8 CPUs"
482	depends on SMP
483	---help---
484	  This option is needed for the systems that have more than 8 CPUs.
485
486config X86_EXTENDED_PLATFORM
487	bool "Support for extended (non-PC) x86 platforms"
488	default y
489	---help---
490	  If you disable this option then the kernel will only support
491	  standard PC platforms. (which covers the vast majority of
492	  systems out there.)
493
494	  If you enable this option then you'll be able to select support
495	  for the following (non-PC) 32 bit x86 platforms:
496		Goldfish (Android emulator)
497		AMD Elan
498		RDC R-321x SoC
499		SGI 320/540 (Visual Workstation)
500		STA2X11-based (e.g. Northville)
501		Moorestown MID devices
502
503	  If you have one of these systems, or if you want to build a
504	  generic distribution kernel, say Y here - otherwise say N.
505endif
506
507if X86_64
508config X86_EXTENDED_PLATFORM
509	bool "Support for extended (non-PC) x86 platforms"
510	default y
511	---help---
512	  If you disable this option then the kernel will only support
513	  standard PC platforms. (which covers the vast majority of
514	  systems out there.)
515
516	  If you enable this option then you'll be able to select support
517	  for the following (non-PC) 64 bit x86 platforms:
518		Numascale NumaChip
519		ScaleMP vSMP
520		SGI Ultraviolet
521
522	  If you have one of these systems, or if you want to build a
523	  generic distribution kernel, say Y here - otherwise say N.
524endif
525# This is an alphabetically sorted list of 64 bit extended platforms
526# Please maintain the alphabetic order if and when there are additions
527config X86_NUMACHIP
528	bool "Numascale NumaChip"
529	depends on X86_64
530	depends on X86_EXTENDED_PLATFORM
531	depends on NUMA
532	depends on SMP
533	depends on X86_X2APIC
534	depends on PCI_MMCONFIG
535	---help---
536	  Adds support for Numascale NumaChip large-SMP systems. Needed to
537	  enable more than ~168 cores.
538	  If you don't have one of these, you should say N here.
539
540config X86_VSMP
541	bool "ScaleMP vSMP"
542	select HYPERVISOR_GUEST
543	select PARAVIRT
544	depends on X86_64 && PCI
545	depends on X86_EXTENDED_PLATFORM
546	depends on SMP
547	---help---
548	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
549	  supposed to run on these EM64T-based machines.  Only choose this option
550	  if you have one of these machines.
551
552config X86_UV
553	bool "SGI Ultraviolet"
554	depends on X86_64
555	depends on X86_EXTENDED_PLATFORM
556	depends on NUMA
557	depends on EFI
558	depends on X86_X2APIC
559	depends on PCI
560	---help---
561	  This option is needed in order to support SGI Ultraviolet systems.
562	  If you don't have one of these, you should say N here.
563
564# Following is an alphabetically sorted list of 32 bit extended platforms
565# Please maintain the alphabetic order if and when there are additions
566
567config X86_GOLDFISH
568	bool "Goldfish (Virtual Platform)"
569	depends on X86_EXTENDED_PLATFORM
570	---help---
571	 Enable support for the Goldfish virtual platform used primarily
572	 for Android development. Unless you are building for the Android
573	 Goldfish emulator say N here.
574
575config X86_INTEL_CE
576	bool "CE4100 TV platform"
577	depends on PCI
578	depends on PCI_GODIRECT
579	depends on X86_IO_APIC
580	depends on X86_32
581	depends on X86_EXTENDED_PLATFORM
582	select X86_REBOOTFIXUPS
583	select OF
584	select OF_EARLY_FLATTREE
585	---help---
586	  Select for the Intel CE media processor (CE4100) SOC.
587	  This option compiles in support for the CE4100 SOC for settop
588	  boxes and media devices.
589
590config X86_INTEL_MID
591	bool "Intel MID platform support"
592	depends on X86_EXTENDED_PLATFORM
593	depends on X86_PLATFORM_DEVICES
594	depends on PCI
595	depends on X86_64 || (PCI_GOANY && X86_32)
596	depends on X86_IO_APIC
597	select SFI
598	select I2C
599	select DW_APB_TIMER
600	select APB_TIMER
601	select INTEL_SCU_PCI
602	select MFD_INTEL_MSIC
603	---help---
604	  Select to build a kernel capable of supporting Intel MID (Mobile
605	  Internet Device) platform systems which do not have the PCI legacy
606	  interfaces. If you are building for a PC class system say N here.
607
608	  Intel MID platforms are based on an Intel processor and chipset which
609	  consume less power than most of the x86 derivatives.
610
611config X86_INTEL_QUARK
612	bool "Intel Quark platform support"
613	depends on X86_32
614	depends on X86_EXTENDED_PLATFORM
615	depends on X86_PLATFORM_DEVICES
616	depends on X86_TSC
617	depends on PCI
618	depends on PCI_GOANY
619	depends on X86_IO_APIC
620	select IOSF_MBI
621	select INTEL_IMR
622	select COMMON_CLK
623	---help---
624	  Select to include support for Quark X1000 SoC.
625	  Say Y here if you have a Quark based system such as the Arduino
626	  compatible Intel Galileo.
627
628config X86_INTEL_LPSS
629	bool "Intel Low Power Subsystem Support"
630	depends on X86 && ACPI && PCI
631	select COMMON_CLK
632	select PINCTRL
633	select IOSF_MBI
634	---help---
635	  Select to build support for Intel Low Power Subsystem such as
636	  found on Intel Lynxpoint PCH. Selecting this option enables
637	  things like clock tree (common clock framework) and pincontrol
638	  which are needed by the LPSS peripheral drivers.
639
640config X86_AMD_PLATFORM_DEVICE
641	bool "AMD ACPI2Platform devices support"
642	depends on ACPI
643	select COMMON_CLK
644	select PINCTRL
645	---help---
646	  Select to interpret AMD specific ACPI device to platform device
647	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
648	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
649	  implemented under PINCTRL subsystem.
650
651config IOSF_MBI
652	tristate "Intel SoC IOSF Sideband support for SoC platforms"
653	depends on PCI
654	---help---
655	  This option enables sideband register access support for Intel SoC
656	  platforms. On these platforms the IOSF sideband is used in lieu of
657	  MSR's for some register accesses, mostly but not limited to thermal
658	  and power. Drivers may query the availability of this device to
659	  determine if they need the sideband in order to work on these
660	  platforms. The sideband is available on the following SoC products.
661	  This list is not meant to be exclusive.
662	   - BayTrail
663	   - Braswell
664	   - Quark
665
666	  You should say Y if you are running a kernel on one of these SoC's.
667
668config IOSF_MBI_DEBUG
669	bool "Enable IOSF sideband access through debugfs"
670	depends on IOSF_MBI && DEBUG_FS
671	---help---
672	  Select this option to expose the IOSF sideband access registers (MCR,
673	  MDR, MCRX) through debugfs to write and read register information from
674	  different units on the SoC. This is most useful for obtaining device
675	  state information for debug and analysis. As this is a general access
676	  mechanism, users of this option would have specific knowledge of the
677	  device they want to access.
678
679	  If you don't require the option or are in doubt, say N.
680
681config X86_RDC321X
682	bool "RDC R-321x SoC"
683	depends on X86_32
684	depends on X86_EXTENDED_PLATFORM
685	select M486
686	select X86_REBOOTFIXUPS
687	---help---
688	  This option is needed for RDC R-321x system-on-chip, also known
689	  as R-8610-(G).
690	  If you don't have one of these chips, you should say N here.
691
692config X86_32_NON_STANDARD
693	bool "Support non-standard 32-bit SMP architectures"
694	depends on X86_32 && SMP
695	depends on X86_EXTENDED_PLATFORM
696	---help---
697	  This option compiles in the bigsmp and STA2X11 default
698	  subarchitectures.  It is intended for a generic binary
699	  kernel. If you select them all, kernel will probe it one by
700	  one and will fallback to default.
701
702# Alphabetically sorted list of Non standard 32 bit platforms
703
704config X86_SUPPORTS_MEMORY_FAILURE
705	def_bool y
706	# MCE code calls memory_failure():
707	depends on X86_MCE
708	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
709	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
710	depends on X86_64 || !SPARSEMEM
711	select ARCH_SUPPORTS_MEMORY_FAILURE
712
713config STA2X11
714	bool "STA2X11 Companion Chip Support"
715	depends on X86_32_NON_STANDARD && PCI
716	select SWIOTLB
717	select MFD_STA2X11
718	select GPIOLIB
719	---help---
720	  This adds support for boards based on the STA2X11 IO-Hub,
721	  a.k.a. "ConneXt". The chip is used in place of the standard
722	  PC chipset, so all "standard" peripherals are missing. If this
723	  option is selected the kernel will still be able to boot on
724	  standard PC machines.
725
726config X86_32_IRIS
727	tristate "Eurobraille/Iris poweroff module"
728	depends on X86_32
729	---help---
730	  The Iris machines from EuroBraille do not have APM or ACPI support
731	  to shut themselves down properly.  A special I/O sequence is
732	  needed to do so, which is what this module does at
733	  kernel shutdown.
734
735	  This is only for Iris machines from EuroBraille.
736
737	  If unused, say N.
738
739config SCHED_OMIT_FRAME_POINTER
740	def_bool y
741	prompt "Single-depth WCHAN output"
742	depends on X86
743	---help---
744	  Calculate simpler /proc/<PID>/wchan values. If this option
745	  is disabled then wchan values will recurse back to the
746	  caller function. This provides more accurate wchan values,
747	  at the expense of slightly more scheduling overhead.
748
749	  If in doubt, say "Y".
750
751menuconfig HYPERVISOR_GUEST
752	bool "Linux guest support"
753	---help---
754	  Say Y here to enable options for running Linux under various hyper-
755	  visors. This option enables basic hypervisor detection and platform
756	  setup.
757
758	  If you say N, all options in this submenu will be skipped and
759	  disabled, and Linux guest support won't be built in.
760
761if HYPERVISOR_GUEST
762
763config PARAVIRT
764	bool "Enable paravirtualization code"
765	---help---
766	  This changes the kernel so it can modify itself when it is run
767	  under a hypervisor, potentially improving performance significantly
768	  over full virtualization.  However, when run without a hypervisor
769	  the kernel is theoretically slower and slightly larger.
770
771config PARAVIRT_XXL
772	bool
773
774config PARAVIRT_DEBUG
775	bool "paravirt-ops debugging"
776	depends on PARAVIRT && DEBUG_KERNEL
777	---help---
778	  Enable to debug paravirt_ops internals.  Specifically, BUG if
779	  a paravirt_op is missing when it is called.
780
781config PARAVIRT_SPINLOCKS
782	bool "Paravirtualization layer for spinlocks"
783	depends on PARAVIRT && SMP
784	---help---
785	  Paravirtualized spinlocks allow a pvops backend to replace the
786	  spinlock implementation with something virtualization-friendly
787	  (for example, block the virtual CPU rather than spinning).
788
789	  It has a minimal impact on native kernels and gives a nice performance
790	  benefit on paravirtualized KVM / Xen kernels.
791
792	  If you are unsure how to answer this question, answer Y.
793
794config X86_HV_CALLBACK_VECTOR
795	def_bool n
796
797source "arch/x86/xen/Kconfig"
798
799config KVM_GUEST
800	bool "KVM Guest support (including kvmclock)"
801	depends on PARAVIRT
802	select PARAVIRT_CLOCK
803	select ARCH_CPUIDLE_HALTPOLL
804	default y
805	---help---
806	  This option enables various optimizations for running under the KVM
807	  hypervisor. It includes a paravirtualized clock, so that instead
808	  of relying on a PIT (or probably other) emulation by the
809	  underlying device model, the host provides the guest with
810	  timing infrastructure such as time of day, and system time
811
812config ARCH_CPUIDLE_HALTPOLL
813	def_bool n
814	prompt "Disable host haltpoll when loading haltpoll driver"
815	help
816	  If virtualized under KVM, disable host haltpoll.
817
818config PVH
819	bool "Support for running PVH guests"
820	---help---
821	  This option enables the PVH entry point for guest virtual machines
822	  as specified in the x86/HVM direct boot ABI.
823
824config KVM_DEBUG_FS
825	bool "Enable debug information for KVM Guests in debugfs"
826	depends on KVM_GUEST && DEBUG_FS
827	---help---
828	  This option enables collection of various statistics for KVM guest.
829	  Statistics are displayed in debugfs filesystem. Enabling this option
830	  may incur significant overhead.
831
832config PARAVIRT_TIME_ACCOUNTING
833	bool "Paravirtual steal time accounting"
834	depends on PARAVIRT
835	---help---
836	  Select this option to enable fine granularity task steal time
837	  accounting. Time spent executing other tasks in parallel with
838	  the current vCPU is discounted from the vCPU power. To account for
839	  that, there can be a small performance impact.
840
841	  If in doubt, say N here.
842
843config PARAVIRT_CLOCK
844	bool
845
846config JAILHOUSE_GUEST
847	bool "Jailhouse non-root cell support"
848	depends on X86_64 && PCI
849	select X86_PM_TIMER
850	---help---
851	  This option allows to run Linux as guest in a Jailhouse non-root
852	  cell. You can leave this option disabled if you only want to start
853	  Jailhouse and run Linux afterwards in the root cell.
854
855config ACRN_GUEST
856	bool "ACRN Guest support"
857	depends on X86_64
858	select X86_HV_CALLBACK_VECTOR
859	help
860	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
861	  a flexible, lightweight reference open-source hypervisor, built with
862	  real-time and safety-criticality in mind. It is built for embedded
863	  IOT with small footprint and real-time features. More details can be
864	  found in https://projectacrn.org/.
865
866endif #HYPERVISOR_GUEST
867
868source "arch/x86/Kconfig.cpu"
869
870config HPET_TIMER
871	def_bool X86_64
872	prompt "HPET Timer Support" if X86_32
873	---help---
874	  Use the IA-PC HPET (High Precision Event Timer) to manage
875	  time in preference to the PIT and RTC, if a HPET is
876	  present.
877	  HPET is the next generation timer replacing legacy 8254s.
878	  The HPET provides a stable time base on SMP
879	  systems, unlike the TSC, but it is more expensive to access,
880	  as it is off-chip.  The interface used is documented
881	  in the HPET spec, revision 1.
882
883	  You can safely choose Y here.  However, HPET will only be
884	  activated if the platform and the BIOS support this feature.
885	  Otherwise the 8254 will be used for timing services.
886
887	  Choose N to continue using the legacy 8254 timer.
888
889config HPET_EMULATE_RTC
890	def_bool y
891	depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
892
893config APB_TIMER
894	def_bool y if X86_INTEL_MID
895	prompt "Intel MID APB Timer Support" if X86_INTEL_MID
896	select DW_APB_TIMER
897	depends on X86_INTEL_MID && SFI
898	help
899	 APB timer is the replacement for 8254, HPET on X86 MID platforms.
900	 The APBT provides a stable time base on SMP
901	 systems, unlike the TSC, but it is more expensive to access,
902	 as it is off-chip. APB timers are always running regardless of CPU
903	 C states, they are used as per CPU clockevent device when possible.
904
905# Mark as expert because too many people got it wrong.
906# The code disables itself when not needed.
907config DMI
908	default y
909	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
910	bool "Enable DMI scanning" if EXPERT
911	---help---
912	  Enabled scanning of DMI to identify machine quirks. Say Y
913	  here unless you have verified that your setup is not
914	  affected by entries in the DMI blacklist. Required by PNP
915	  BIOS code.
916
917config GART_IOMMU
918	bool "Old AMD GART IOMMU support"
919	select IOMMU_HELPER
920	select SWIOTLB
921	depends on X86_64 && PCI && AMD_NB
922	---help---
923	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
924	  GART based hardware IOMMUs.
925
926	  The GART supports full DMA access for devices with 32-bit access
927	  limitations, on systems with more than 3 GB. This is usually needed
928	  for USB, sound, many IDE/SATA chipsets and some other devices.
929
930	  Newer systems typically have a modern AMD IOMMU, supported via
931	  the CONFIG_AMD_IOMMU=y config option.
932
933	  In normal configurations this driver is only active when needed:
934	  there's more than 3 GB of memory and the system contains a
935	  32-bit limited device.
936
937	  If unsure, say Y.
938
939config MAXSMP
940	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
941	depends on X86_64 && SMP && DEBUG_KERNEL
942	select CPUMASK_OFFSTACK
943	---help---
944	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
945	  If unsure, say N.
946
947#
948# The maximum number of CPUs supported:
949#
950# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
951# and which can be configured interactively in the
952# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
953#
954# The ranges are different on 32-bit and 64-bit kernels, depending on
955# hardware capabilities and scalability features of the kernel.
956#
957# ( If MAXSMP is enabled we just use the highest possible value and disable
958#   interactive configuration. )
959#
960
961config NR_CPUS_RANGE_BEGIN
962	int
963	default NR_CPUS_RANGE_END if MAXSMP
964	default    1 if !SMP
965	default    2
966
967config NR_CPUS_RANGE_END
968	int
969	depends on X86_32
970	default   64 if  SMP &&  X86_BIGSMP
971	default    8 if  SMP && !X86_BIGSMP
972	default    1 if !SMP
973
974config NR_CPUS_RANGE_END
975	int
976	depends on X86_64
977	default 8192 if  SMP && CPUMASK_OFFSTACK
978	default  512 if  SMP && !CPUMASK_OFFSTACK
979	default    1 if !SMP
980
981config NR_CPUS_DEFAULT
982	int
983	depends on X86_32
984	default   32 if  X86_BIGSMP
985	default    8 if  SMP
986	default    1 if !SMP
987
988config NR_CPUS_DEFAULT
989	int
990	depends on X86_64
991	default 8192 if  MAXSMP
992	default   64 if  SMP
993	default    1 if !SMP
994
995config NR_CPUS
996	int "Maximum number of CPUs" if SMP && !MAXSMP
997	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
998	default NR_CPUS_DEFAULT
999	---help---
1000	  This allows you to specify the maximum number of CPUs which this
1001	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1002	  supported value is 8192, otherwise the maximum value is 512.  The
1003	  minimum value which makes sense is 2.
1004
1005	  This is purely to save memory: each supported CPU adds about 8KB
1006	  to the kernel image.
1007
1008config SCHED_SMT
1009	def_bool y if SMP
1010
1011config SCHED_MC
1012	def_bool y
1013	prompt "Multi-core scheduler support"
1014	depends on SMP
1015	---help---
1016	  Multi-core scheduler support improves the CPU scheduler's decision
1017	  making when dealing with multi-core CPU chips at a cost of slightly
1018	  increased overhead in some places. If unsure say N here.
1019
1020config SCHED_MC_PRIO
1021	bool "CPU core priorities scheduler support"
1022	depends on SCHED_MC && CPU_SUP_INTEL
1023	select X86_INTEL_PSTATE
1024	select CPU_FREQ
1025	default y
1026	---help---
1027	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1028	  core ordering determined at manufacturing time, which allows
1029	  certain cores to reach higher turbo frequencies (when running
1030	  single threaded workloads) than others.
1031
1032	  Enabling this kernel feature teaches the scheduler about
1033	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1034	  scheduler's CPU selection logic accordingly, so that higher
1035	  overall system performance can be achieved.
1036
1037	  This feature will have no effect on CPUs without this feature.
1038
1039	  If unsure say Y here.
1040
1041config UP_LATE_INIT
1042	def_bool y
1043	depends on !SMP && X86_LOCAL_APIC
1044
1045config X86_UP_APIC
1046	bool "Local APIC support on uniprocessors" if !PCI_MSI
1047	default PCI_MSI
1048	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1049	---help---
1050	  A local APIC (Advanced Programmable Interrupt Controller) is an
1051	  integrated interrupt controller in the CPU. If you have a single-CPU
1052	  system which has a processor with a local APIC, you can say Y here to
1053	  enable and use it. If you say Y here even though your machine doesn't
1054	  have a local APIC, then the kernel will still run with no slowdown at
1055	  all. The local APIC supports CPU-generated self-interrupts (timer,
1056	  performance counters), and the NMI watchdog which detects hard
1057	  lockups.
1058
1059config X86_UP_IOAPIC
1060	bool "IO-APIC support on uniprocessors"
1061	depends on X86_UP_APIC
1062	---help---
1063	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1064	  SMP-capable replacement for PC-style interrupt controllers. Most
1065	  SMP systems and many recent uniprocessor systems have one.
1066
1067	  If you have a single-CPU system with an IO-APIC, you can say Y here
1068	  to use it. If you say Y here even though your machine doesn't have
1069	  an IO-APIC, then the kernel will still run with no slowdown at all.
1070
1071config X86_LOCAL_APIC
1072	def_bool y
1073	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1074	select IRQ_DOMAIN_HIERARCHY
1075	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1076
1077config X86_IO_APIC
1078	def_bool y
1079	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1080
1081config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1082	bool "Reroute for broken boot IRQs"
1083	depends on X86_IO_APIC
1084	---help---
1085	  This option enables a workaround that fixes a source of
1086	  spurious interrupts. This is recommended when threaded
1087	  interrupt handling is used on systems where the generation of
1088	  superfluous "boot interrupts" cannot be disabled.
1089
1090	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1091	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1092	  kernel does during interrupt handling). On chipsets where this
1093	  boot IRQ generation cannot be disabled, this workaround keeps
1094	  the original IRQ line masked so that only the equivalent "boot
1095	  IRQ" is delivered to the CPUs. The workaround also tells the
1096	  kernel to set up the IRQ handler on the boot IRQ line. In this
1097	  way only one interrupt is delivered to the kernel. Otherwise
1098	  the spurious second interrupt may cause the kernel to bring
1099	  down (vital) interrupt lines.
1100
1101	  Only affects "broken" chipsets. Interrupt sharing may be
1102	  increased on these systems.
1103
1104config X86_MCE
1105	bool "Machine Check / overheating reporting"
1106	select GENERIC_ALLOCATOR
1107	default y
1108	---help---
1109	  Machine Check support allows the processor to notify the
1110	  kernel if it detects a problem (e.g. overheating, data corruption).
1111	  The action the kernel takes depends on the severity of the problem,
1112	  ranging from warning messages to halting the machine.
1113
1114config X86_MCELOG_LEGACY
1115	bool "Support for deprecated /dev/mcelog character device"
1116	depends on X86_MCE
1117	---help---
1118	  Enable support for /dev/mcelog which is needed by the old mcelog
1119	  userspace logging daemon. Consider switching to the new generation
1120	  rasdaemon solution.
1121
1122config X86_MCE_INTEL
1123	def_bool y
1124	prompt "Intel MCE features"
1125	depends on X86_MCE && X86_LOCAL_APIC
1126	---help---
1127	   Additional support for intel specific MCE features such as
1128	   the thermal monitor.
1129
1130config X86_MCE_AMD
1131	def_bool y
1132	prompt "AMD MCE features"
1133	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1134	---help---
1135	   Additional support for AMD specific MCE features such as
1136	   the DRAM Error Threshold.
1137
1138config X86_ANCIENT_MCE
1139	bool "Support for old Pentium 5 / WinChip machine checks"
1140	depends on X86_32 && X86_MCE
1141	---help---
1142	  Include support for machine check handling on old Pentium 5 or WinChip
1143	  systems. These typically need to be enabled explicitly on the command
1144	  line.
1145
1146config X86_MCE_THRESHOLD
1147	depends on X86_MCE_AMD || X86_MCE_INTEL
1148	def_bool y
1149
1150config X86_MCE_INJECT
1151	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1152	tristate "Machine check injector support"
1153	---help---
1154	  Provide support for injecting machine checks for testing purposes.
1155	  If you don't know what a machine check is and you don't do kernel
1156	  QA it is safe to say n.
1157
1158config X86_THERMAL_VECTOR
1159	def_bool y
1160	depends on X86_MCE_INTEL
1161
1162source "arch/x86/events/Kconfig"
1163
1164config X86_LEGACY_VM86
1165	bool "Legacy VM86 support"
1166	depends on X86_32
1167	---help---
1168	  This option allows user programs to put the CPU into V8086
1169	  mode, which is an 80286-era approximation of 16-bit real mode.
1170
1171	  Some very old versions of X and/or vbetool require this option
1172	  for user mode setting.  Similarly, DOSEMU will use it if
1173	  available to accelerate real mode DOS programs.  However, any
1174	  recent version of DOSEMU, X, or vbetool should be fully
1175	  functional even without kernel VM86 support, as they will all
1176	  fall back to software emulation. Nevertheless, if you are using
1177	  a 16-bit DOS program where 16-bit performance matters, vm86
1178	  mode might be faster than emulation and you might want to
1179	  enable this option.
1180
1181	  Note that any app that works on a 64-bit kernel is unlikely to
1182	  need this option, as 64-bit kernels don't, and can't, support
1183	  V8086 mode. This option is also unrelated to 16-bit protected
1184	  mode and is not needed to run most 16-bit programs under Wine.
1185
1186	  Enabling this option increases the complexity of the kernel
1187	  and slows down exception handling a tiny bit.
1188
1189	  If unsure, say N here.
1190
1191config VM86
1192	bool
1193	default X86_LEGACY_VM86
1194
1195config X86_16BIT
1196	bool "Enable support for 16-bit segments" if EXPERT
1197	default y
1198	depends on MODIFY_LDT_SYSCALL
1199	---help---
1200	  This option is required by programs like Wine to run 16-bit
1201	  protected mode legacy code on x86 processors.  Disabling
1202	  this option saves about 300 bytes on i386, or around 6K text
1203	  plus 16K runtime memory on x86-64,
1204
1205config X86_ESPFIX32
1206	def_bool y
1207	depends on X86_16BIT && X86_32
1208
1209config X86_ESPFIX64
1210	def_bool y
1211	depends on X86_16BIT && X86_64
1212
1213config X86_VSYSCALL_EMULATION
1214	bool "Enable vsyscall emulation" if EXPERT
1215	default y
1216	depends on X86_64
1217	---help---
1218	 This enables emulation of the legacy vsyscall page.  Disabling
1219	 it is roughly equivalent to booting with vsyscall=none, except
1220	 that it will also disable the helpful warning if a program
1221	 tries to use a vsyscall.  With this option set to N, offending
1222	 programs will just segfault, citing addresses of the form
1223	 0xffffffffff600?00.
1224
1225	 This option is required by many programs built before 2013, and
1226	 care should be used even with newer programs if set to N.
1227
1228	 Disabling this option saves about 7K of kernel size and
1229	 possibly 4K of additional runtime pagetable memory.
1230
1231config X86_IOPL_IOPERM
1232	bool "IOPERM and IOPL Emulation"
1233	default y
1234	---help---
1235	  This enables the ioperm() and iopl() syscalls which are necessary
1236	  for legacy applications.
1237
1238	  Legacy IOPL support is an overbroad mechanism which allows user
1239	  space aside of accessing all 65536 I/O ports also to disable
1240	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1241	  capabilities and permission from potentially active security
1242	  modules.
1243
1244	  The emulation restricts the functionality of the syscall to
1245	  only allowing the full range I/O port access, but prevents the
1246	  ability to disable interrupts from user space which would be
1247	  granted if the hardware IOPL mechanism would be used.
1248
1249config TOSHIBA
1250	tristate "Toshiba Laptop support"
1251	depends on X86_32
1252	---help---
1253	  This adds a driver to safely access the System Management Mode of
1254	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1255	  not work on models with a Phoenix BIOS. The System Management Mode
1256	  is used to set the BIOS and power saving options on Toshiba portables.
1257
1258	  For information on utilities to make use of this driver see the
1259	  Toshiba Linux utilities web site at:
1260	  <http://www.buzzard.org.uk/toshiba/>.
1261
1262	  Say Y if you intend to run this kernel on a Toshiba portable.
1263	  Say N otherwise.
1264
1265config I8K
1266	tristate "Dell i8k legacy laptop support"
1267	select HWMON
1268	select SENSORS_DELL_SMM
1269	---help---
1270	  This option enables legacy /proc/i8k userspace interface in hwmon
1271	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1272	  temperature and allows controlling fan speeds of Dell laptops via
1273	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1274	  it reports also power and hotkey status. For fan speed control is
1275	  needed userspace package i8kutils.
1276
1277	  Say Y if you intend to run this kernel on old Dell laptops or want to
1278	  use userspace package i8kutils.
1279	  Say N otherwise.
1280
1281config X86_REBOOTFIXUPS
1282	bool "Enable X86 board specific fixups for reboot"
1283	depends on X86_32
1284	---help---
1285	  This enables chipset and/or board specific fixups to be done
1286	  in order to get reboot to work correctly. This is only needed on
1287	  some combinations of hardware and BIOS. The symptom, for which
1288	  this config is intended, is when reboot ends with a stalled/hung
1289	  system.
1290
1291	  Currently, the only fixup is for the Geode machines using
1292	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1293
1294	  Say Y if you want to enable the fixup. Currently, it's safe to
1295	  enable this option even if you don't need it.
1296	  Say N otherwise.
1297
1298config MICROCODE
1299	bool "CPU microcode loading support"
1300	default y
1301	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1302	select FW_LOADER
1303	---help---
1304	  If you say Y here, you will be able to update the microcode on
1305	  Intel and AMD processors. The Intel support is for the IA32 family,
1306	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1307	  AMD support is for families 0x10 and later. You will obviously need
1308	  the actual microcode binary data itself which is not shipped with
1309	  the Linux kernel.
1310
1311	  The preferred method to load microcode from a detached initrd is described
1312	  in Documentation/x86/microcode.rst. For that you need to enable
1313	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1314	  initrd for microcode blobs.
1315
1316	  In addition, you can build the microcode into the kernel. For that you
1317	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1318	  config option.
1319
1320config MICROCODE_INTEL
1321	bool "Intel microcode loading support"
1322	depends on MICROCODE
1323	default MICROCODE
1324	select FW_LOADER
1325	---help---
1326	  This options enables microcode patch loading support for Intel
1327	  processors.
1328
1329	  For the current Intel microcode data package go to
1330	  <https://downloadcenter.intel.com> and search for
1331	  'Linux Processor Microcode Data File'.
1332
1333config MICROCODE_AMD
1334	bool "AMD microcode loading support"
1335	depends on MICROCODE
1336	select FW_LOADER
1337	---help---
1338	  If you select this option, microcode patch loading support for AMD
1339	  processors will be enabled.
1340
1341config MICROCODE_OLD_INTERFACE
1342	bool "Ancient loading interface (DEPRECATED)"
1343	default n
1344	depends on MICROCODE
1345	---help---
1346	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1347	  which was used by userspace tools like iucode_tool and microcode.ctl.
1348	  It is inadequate because it runs too late to be able to properly
1349	  load microcode on a machine and it needs special tools. Instead, you
1350	  should've switched to the early loading method with the initrd or
1351	  builtin microcode by now: Documentation/x86/microcode.rst
1352
1353config X86_MSR
1354	tristate "/dev/cpu/*/msr - Model-specific register support"
1355	---help---
1356	  This device gives privileged processes access to the x86
1357	  Model-Specific Registers (MSRs).  It is a character device with
1358	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1359	  MSR accesses are directed to a specific CPU on multi-processor
1360	  systems.
1361
1362config X86_CPUID
1363	tristate "/dev/cpu/*/cpuid - CPU information support"
1364	---help---
1365	  This device gives processes access to the x86 CPUID instruction to
1366	  be executed on a specific processor.  It is a character device
1367	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1368	  /dev/cpu/31/cpuid.
1369
1370choice
1371	prompt "High Memory Support"
1372	default HIGHMEM4G
1373	depends on X86_32
1374
1375config NOHIGHMEM
1376	bool "off"
1377	---help---
1378	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1379	  However, the address space of 32-bit x86 processors is only 4
1380	  Gigabytes large. That means that, if you have a large amount of
1381	  physical memory, not all of it can be "permanently mapped" by the
1382	  kernel. The physical memory that's not permanently mapped is called
1383	  "high memory".
1384
1385	  If you are compiling a kernel which will never run on a machine with
1386	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1387	  choice and suitable for most users). This will result in a "3GB/1GB"
1388	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1389	  space and the remaining part of the 4GB virtual memory space is used
1390	  by the kernel to permanently map as much physical memory as
1391	  possible.
1392
1393	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1394	  answer "4GB" here.
1395
1396	  If more than 4 Gigabytes is used then answer "64GB" here. This
1397	  selection turns Intel PAE (Physical Address Extension) mode on.
1398	  PAE implements 3-level paging on IA32 processors. PAE is fully
1399	  supported by Linux, PAE mode is implemented on all recent Intel
1400	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1401	  then the kernel will not boot on CPUs that don't support PAE!
1402
1403	  The actual amount of total physical memory will either be
1404	  auto detected or can be forced by using a kernel command line option
1405	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1406	  your boot loader (lilo or loadlin) about how to pass options to the
1407	  kernel at boot time.)
1408
1409	  If unsure, say "off".
1410
1411config HIGHMEM4G
1412	bool "4GB"
1413	---help---
1414	  Select this if you have a 32-bit processor and between 1 and 4
1415	  gigabytes of physical RAM.
1416
1417config HIGHMEM64G
1418	bool "64GB"
1419	depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1420	select X86_PAE
1421	---help---
1422	  Select this if you have a 32-bit processor and more than 4
1423	  gigabytes of physical RAM.
1424
1425endchoice
1426
1427choice
1428	prompt "Memory split" if EXPERT
1429	default VMSPLIT_3G
1430	depends on X86_32
1431	---help---
1432	  Select the desired split between kernel and user memory.
1433
1434	  If the address range available to the kernel is less than the
1435	  physical memory installed, the remaining memory will be available
1436	  as "high memory". Accessing high memory is a little more costly
1437	  than low memory, as it needs to be mapped into the kernel first.
1438	  Note that increasing the kernel address space limits the range
1439	  available to user programs, making the address space there
1440	  tighter.  Selecting anything other than the default 3G/1G split
1441	  will also likely make your kernel incompatible with binary-only
1442	  kernel modules.
1443
1444	  If you are not absolutely sure what you are doing, leave this
1445	  option alone!
1446
1447	config VMSPLIT_3G
1448		bool "3G/1G user/kernel split"
1449	config VMSPLIT_3G_OPT
1450		depends on !X86_PAE
1451		bool "3G/1G user/kernel split (for full 1G low memory)"
1452	config VMSPLIT_2G
1453		bool "2G/2G user/kernel split"
1454	config VMSPLIT_2G_OPT
1455		depends on !X86_PAE
1456		bool "2G/2G user/kernel split (for full 2G low memory)"
1457	config VMSPLIT_1G
1458		bool "1G/3G user/kernel split"
1459endchoice
1460
1461config PAGE_OFFSET
1462	hex
1463	default 0xB0000000 if VMSPLIT_3G_OPT
1464	default 0x80000000 if VMSPLIT_2G
1465	default 0x78000000 if VMSPLIT_2G_OPT
1466	default 0x40000000 if VMSPLIT_1G
1467	default 0xC0000000
1468	depends on X86_32
1469
1470config HIGHMEM
1471	def_bool y
1472	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1473
1474config X86_PAE
1475	bool "PAE (Physical Address Extension) Support"
1476	depends on X86_32 && !HIGHMEM4G
1477	select PHYS_ADDR_T_64BIT
1478	select SWIOTLB
1479	---help---
1480	  PAE is required for NX support, and furthermore enables
1481	  larger swapspace support for non-overcommit purposes. It
1482	  has the cost of more pagetable lookup overhead, and also
1483	  consumes more pagetable space per process.
1484
1485config X86_5LEVEL
1486	bool "Enable 5-level page tables support"
1487	default y
1488	select DYNAMIC_MEMORY_LAYOUT
1489	select SPARSEMEM_VMEMMAP
1490	depends on X86_64
1491	---help---
1492	  5-level paging enables access to larger address space:
1493	  upto 128 PiB of virtual address space and 4 PiB of
1494	  physical address space.
1495
1496	  It will be supported by future Intel CPUs.
1497
1498	  A kernel with the option enabled can be booted on machines that
1499	  support 4- or 5-level paging.
1500
1501	  See Documentation/x86/x86_64/5level-paging.rst for more
1502	  information.
1503
1504	  Say N if unsure.
1505
1506config X86_DIRECT_GBPAGES
1507	def_bool y
1508	depends on X86_64
1509	---help---
1510	  Certain kernel features effectively disable kernel
1511	  linear 1 GB mappings (even if the CPU otherwise
1512	  supports them), so don't confuse the user by printing
1513	  that we have them enabled.
1514
1515config X86_CPA_STATISTICS
1516	bool "Enable statistic for Change Page Attribute"
1517	depends on DEBUG_FS
1518	---help---
1519	  Expose statistics about the Change Page Attribute mechanism, which
1520	  helps to determine the effectiveness of preserving large and huge
1521	  page mappings when mapping protections are changed.
1522
1523config AMD_MEM_ENCRYPT
1524	bool "AMD Secure Memory Encryption (SME) support"
1525	depends on X86_64 && CPU_SUP_AMD
1526	select DMA_COHERENT_POOL
1527	select DYNAMIC_PHYSICAL_MASK
1528	select ARCH_USE_MEMREMAP_PROT
1529	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1530	---help---
1531	  Say yes to enable support for the encryption of system memory.
1532	  This requires an AMD processor that supports Secure Memory
1533	  Encryption (SME).
1534
1535config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1536	bool "Activate AMD Secure Memory Encryption (SME) by default"
1537	default y
1538	depends on AMD_MEM_ENCRYPT
1539	---help---
1540	  Say yes to have system memory encrypted by default if running on
1541	  an AMD processor that supports Secure Memory Encryption (SME).
1542
1543	  If set to Y, then the encryption of system memory can be
1544	  deactivated with the mem_encrypt=off command line option.
1545
1546	  If set to N, then the encryption of system memory can be
1547	  activated with the mem_encrypt=on command line option.
1548
1549# Common NUMA Features
1550config NUMA
1551	bool "NUMA Memory Allocation and Scheduler Support"
1552	depends on SMP
1553	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1554	default y if X86_BIGSMP
1555	---help---
1556	  Enable NUMA (Non-Uniform Memory Access) support.
1557
1558	  The kernel will try to allocate memory used by a CPU on the
1559	  local memory controller of the CPU and add some more
1560	  NUMA awareness to the kernel.
1561
1562	  For 64-bit this is recommended if the system is Intel Core i7
1563	  (or later), AMD Opteron, or EM64T NUMA.
1564
1565	  For 32-bit this is only needed if you boot a 32-bit
1566	  kernel on a 64-bit NUMA platform.
1567
1568	  Otherwise, you should say N.
1569
1570config AMD_NUMA
1571	def_bool y
1572	prompt "Old style AMD Opteron NUMA detection"
1573	depends on X86_64 && NUMA && PCI
1574	---help---
1575	  Enable AMD NUMA node topology detection.  You should say Y here if
1576	  you have a multi processor AMD system. This uses an old method to
1577	  read the NUMA configuration directly from the builtin Northbridge
1578	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1579	  which also takes priority if both are compiled in.
1580
1581config X86_64_ACPI_NUMA
1582	def_bool y
1583	prompt "ACPI NUMA detection"
1584	depends on X86_64 && NUMA && ACPI && PCI
1585	select ACPI_NUMA
1586	---help---
1587	  Enable ACPI SRAT based node topology detection.
1588
1589config NUMA_EMU
1590	bool "NUMA emulation"
1591	depends on NUMA
1592	---help---
1593	  Enable NUMA emulation. A flat machine will be split
1594	  into virtual nodes when booted with "numa=fake=N", where N is the
1595	  number of nodes. This is only useful for debugging.
1596
1597config NODES_SHIFT
1598	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1599	range 1 10
1600	default "10" if MAXSMP
1601	default "6" if X86_64
1602	default "3"
1603	depends on NEED_MULTIPLE_NODES
1604	---help---
1605	  Specify the maximum number of NUMA Nodes available on the target
1606	  system.  Increases memory reserved to accommodate various tables.
1607
1608config ARCH_FLATMEM_ENABLE
1609	def_bool y
1610	depends on X86_32 && !NUMA
1611
1612config ARCH_SPARSEMEM_ENABLE
1613	def_bool y
1614	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1615	select SPARSEMEM_STATIC if X86_32
1616	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1617
1618config ARCH_SPARSEMEM_DEFAULT
1619	def_bool X86_64 || (NUMA && X86_32)
1620
1621config ARCH_SELECT_MEMORY_MODEL
1622	def_bool y
1623	depends on ARCH_SPARSEMEM_ENABLE
1624
1625config ARCH_MEMORY_PROBE
1626	bool "Enable sysfs memory/probe interface"
1627	depends on X86_64 && MEMORY_HOTPLUG
1628	help
1629	  This option enables a sysfs memory/probe interface for testing.
1630	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1631	  If you are unsure how to answer this question, answer N.
1632
1633config ARCH_PROC_KCORE_TEXT
1634	def_bool y
1635	depends on X86_64 && PROC_KCORE
1636
1637config ILLEGAL_POINTER_VALUE
1638	hex
1639	default 0 if X86_32
1640	default 0xdead000000000000 if X86_64
1641
1642config X86_PMEM_LEGACY_DEVICE
1643	bool
1644
1645config X86_PMEM_LEGACY
1646	tristate "Support non-standard NVDIMMs and ADR protected memory"
1647	depends on PHYS_ADDR_T_64BIT
1648	depends on BLK_DEV
1649	select X86_PMEM_LEGACY_DEVICE
1650	select NUMA_KEEP_MEMINFO if NUMA
1651	select LIBNVDIMM
1652	help
1653	  Treat memory marked using the non-standard e820 type of 12 as used
1654	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1655	  The kernel will offer these regions to the 'pmem' driver so
1656	  they can be used for persistent storage.
1657
1658	  Say Y if unsure.
1659
1660config HIGHPTE
1661	bool "Allocate 3rd-level pagetables from highmem"
1662	depends on HIGHMEM
1663	---help---
1664	  The VM uses one page table entry for each page of physical memory.
1665	  For systems with a lot of RAM, this can be wasteful of precious
1666	  low memory.  Setting this option will put user-space page table
1667	  entries in high memory.
1668
1669config X86_CHECK_BIOS_CORRUPTION
1670	bool "Check for low memory corruption"
1671	---help---
1672	  Periodically check for memory corruption in low memory, which
1673	  is suspected to be caused by BIOS.  Even when enabled in the
1674	  configuration, it is disabled at runtime.  Enable it by
1675	  setting "memory_corruption_check=1" on the kernel command
1676	  line.  By default it scans the low 64k of memory every 60
1677	  seconds; see the memory_corruption_check_size and
1678	  memory_corruption_check_period parameters in
1679	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1680
1681	  When enabled with the default parameters, this option has
1682	  almost no overhead, as it reserves a relatively small amount
1683	  of memory and scans it infrequently.  It both detects corruption
1684	  and prevents it from affecting the running system.
1685
1686	  It is, however, intended as a diagnostic tool; if repeatable
1687	  BIOS-originated corruption always affects the same memory,
1688	  you can use memmap= to prevent the kernel from using that
1689	  memory.
1690
1691config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1692	bool "Set the default setting of memory_corruption_check"
1693	depends on X86_CHECK_BIOS_CORRUPTION
1694	default y
1695	---help---
1696	  Set whether the default state of memory_corruption_check is
1697	  on or off.
1698
1699config X86_RESERVE_LOW
1700	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1701	default 64
1702	range 4 640
1703	---help---
1704	  Specify the amount of low memory to reserve for the BIOS.
1705
1706	  The first page contains BIOS data structures that the kernel
1707	  must not use, so that page must always be reserved.
1708
1709	  By default we reserve the first 64K of physical RAM, as a
1710	  number of BIOSes are known to corrupt that memory range
1711	  during events such as suspend/resume or monitor cable
1712	  insertion, so it must not be used by the kernel.
1713
1714	  You can set this to 4 if you are absolutely sure that you
1715	  trust the BIOS to get all its memory reservations and usages
1716	  right.  If you know your BIOS have problems beyond the
1717	  default 64K area, you can set this to 640 to avoid using the
1718	  entire low memory range.
1719
1720	  If you have doubts about the BIOS (e.g. suspend/resume does
1721	  not work or there's kernel crashes after certain hardware
1722	  hotplug events) then you might want to enable
1723	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1724	  typical corruption patterns.
1725
1726	  Leave this to the default value of 64 if you are unsure.
1727
1728config MATH_EMULATION
1729	bool
1730	depends on MODIFY_LDT_SYSCALL
1731	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1732	---help---
1733	  Linux can emulate a math coprocessor (used for floating point
1734	  operations) if you don't have one. 486DX and Pentium processors have
1735	  a math coprocessor built in, 486SX and 386 do not, unless you added
1736	  a 487DX or 387, respectively. (The messages during boot time can
1737	  give you some hints here ["man dmesg"].) Everyone needs either a
1738	  coprocessor or this emulation.
1739
1740	  If you don't have a math coprocessor, you need to say Y here; if you
1741	  say Y here even though you have a coprocessor, the coprocessor will
1742	  be used nevertheless. (This behavior can be changed with the kernel
1743	  command line option "no387", which comes handy if your coprocessor
1744	  is broken. Try "man bootparam" or see the documentation of your boot
1745	  loader (lilo or loadlin) about how to pass options to the kernel at
1746	  boot time.) This means that it is a good idea to say Y here if you
1747	  intend to use this kernel on different machines.
1748
1749	  More information about the internals of the Linux math coprocessor
1750	  emulation can be found in <file:arch/x86/math-emu/README>.
1751
1752	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1753	  kernel, it won't hurt.
1754
1755config MTRR
1756	def_bool y
1757	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1758	---help---
1759	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1760	  the Memory Type Range Registers (MTRRs) may be used to control
1761	  processor access to memory ranges. This is most useful if you have
1762	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1763	  allows bus write transfers to be combined into a larger transfer
1764	  before bursting over the PCI/AGP bus. This can increase performance
1765	  of image write operations 2.5 times or more. Saying Y here creates a
1766	  /proc/mtrr file which may be used to manipulate your processor's
1767	  MTRRs. Typically the X server should use this.
1768
1769	  This code has a reasonably generic interface so that similar
1770	  control registers on other processors can be easily supported
1771	  as well:
1772
1773	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1774	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1775	  these, the ARRs are used to emulate the MTRRs.
1776	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1777	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1778	  write-combining. All of these processors are supported by this code
1779	  and it makes sense to say Y here if you have one of them.
1780
1781	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1782	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1783	  can lead to all sorts of problems, so it's good to say Y here.
1784
1785	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1786	  just add about 9 KB to your kernel.
1787
1788	  See <file:Documentation/x86/mtrr.rst> for more information.
1789
1790config MTRR_SANITIZER
1791	def_bool y
1792	prompt "MTRR cleanup support"
1793	depends on MTRR
1794	---help---
1795	  Convert MTRR layout from continuous to discrete, so X drivers can
1796	  add writeback entries.
1797
1798	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1799	  The largest mtrr entry size for a continuous block can be set with
1800	  mtrr_chunk_size.
1801
1802	  If unsure, say Y.
1803
1804config MTRR_SANITIZER_ENABLE_DEFAULT
1805	int "MTRR cleanup enable value (0-1)"
1806	range 0 1
1807	default "0"
1808	depends on MTRR_SANITIZER
1809	---help---
1810	  Enable mtrr cleanup default value
1811
1812config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1813	int "MTRR cleanup spare reg num (0-7)"
1814	range 0 7
1815	default "1"
1816	depends on MTRR_SANITIZER
1817	---help---
1818	  mtrr cleanup spare entries default, it can be changed via
1819	  mtrr_spare_reg_nr=N on the kernel command line.
1820
1821config X86_PAT
1822	def_bool y
1823	prompt "x86 PAT support" if EXPERT
1824	depends on MTRR
1825	---help---
1826	  Use PAT attributes to setup page level cache control.
1827
1828	  PATs are the modern equivalents of MTRRs and are much more
1829	  flexible than MTRRs.
1830
1831	  Say N here if you see bootup problems (boot crash, boot hang,
1832	  spontaneous reboots) or a non-working video driver.
1833
1834	  If unsure, say Y.
1835
1836config ARCH_USES_PG_UNCACHED
1837	def_bool y
1838	depends on X86_PAT
1839
1840config ARCH_RANDOM
1841	def_bool y
1842	prompt "x86 architectural random number generator" if EXPERT
1843	---help---
1844	  Enable the x86 architectural RDRAND instruction
1845	  (Intel Bull Mountain technology) to generate random numbers.
1846	  If supported, this is a high bandwidth, cryptographically
1847	  secure hardware random number generator.
1848
1849config X86_SMAP
1850	def_bool y
1851	prompt "Supervisor Mode Access Prevention" if EXPERT
1852	---help---
1853	  Supervisor Mode Access Prevention (SMAP) is a security
1854	  feature in newer Intel processors.  There is a small
1855	  performance cost if this enabled and turned on; there is
1856	  also a small increase in the kernel size if this is enabled.
1857
1858	  If unsure, say Y.
1859
1860config X86_UMIP
1861	def_bool y
1862	prompt "User Mode Instruction Prevention" if EXPERT
1863	---help---
1864	  User Mode Instruction Prevention (UMIP) is a security feature in
1865	  some x86 processors. If enabled, a general protection fault is
1866	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1867	  executed in user mode. These instructions unnecessarily expose
1868	  information about the hardware state.
1869
1870	  The vast majority of applications do not use these instructions.
1871	  For the very few that do, software emulation is provided in
1872	  specific cases in protected and virtual-8086 modes. Emulated
1873	  results are dummy.
1874
1875config X86_INTEL_MEMORY_PROTECTION_KEYS
1876	prompt "Memory Protection Keys"
1877	def_bool y
1878	# Note: only available in 64-bit mode
1879	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1880	select ARCH_USES_HIGH_VMA_FLAGS
1881	select ARCH_HAS_PKEYS
1882	---help---
1883	  Memory Protection Keys provides a mechanism for enforcing
1884	  page-based protections, but without requiring modification of the
1885	  page tables when an application changes protection domains.
1886
1887	  For details, see Documentation/core-api/protection-keys.rst
1888
1889	  If unsure, say y.
1890
1891choice
1892	prompt "TSX enable mode"
1893	depends on CPU_SUP_INTEL
1894	default X86_INTEL_TSX_MODE_OFF
1895	help
1896	  Intel's TSX (Transactional Synchronization Extensions) feature
1897	  allows to optimize locking protocols through lock elision which
1898	  can lead to a noticeable performance boost.
1899
1900	  On the other hand it has been shown that TSX can be exploited
1901	  to form side channel attacks (e.g. TAA) and chances are there
1902	  will be more of those attacks discovered in the future.
1903
1904	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1905	  might override this decision by tsx=on the command line parameter.
1906	  Even with TSX enabled, the kernel will attempt to enable the best
1907	  possible TAA mitigation setting depending on the microcode available
1908	  for the particular machine.
1909
1910	  This option allows to set the default tsx mode between tsx=on, =off
1911	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1912	  details.
1913
1914	  Say off if not sure, auto if TSX is in use but it should be used on safe
1915	  platforms or on if TSX is in use and the security aspect of tsx is not
1916	  relevant.
1917
1918config X86_INTEL_TSX_MODE_OFF
1919	bool "off"
1920	help
1921	  TSX is disabled if possible - equals to tsx=off command line parameter.
1922
1923config X86_INTEL_TSX_MODE_ON
1924	bool "on"
1925	help
1926	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1927	  line parameter.
1928
1929config X86_INTEL_TSX_MODE_AUTO
1930	bool "auto"
1931	help
1932	  TSX is enabled on TSX capable HW that is believed to be safe against
1933	  side channel attacks- equals the tsx=auto command line parameter.
1934endchoice
1935
1936config EFI
1937	bool "EFI runtime service support"
1938	depends on ACPI
1939	select UCS2_STRING
1940	select EFI_RUNTIME_WRAPPERS
1941	---help---
1942	  This enables the kernel to use EFI runtime services that are
1943	  available (such as the EFI variable services).
1944
1945	  This option is only useful on systems that have EFI firmware.
1946	  In addition, you should use the latest ELILO loader available
1947	  at <http://elilo.sourceforge.net> in order to take advantage
1948	  of EFI runtime services. However, even with this option, the
1949	  resultant kernel should continue to boot on existing non-EFI
1950	  platforms.
1951
1952config EFI_STUB
1953	bool "EFI stub support"
1954	depends on EFI && !X86_USE_3DNOW
1955	depends on $(cc-option,-mabi=ms) || X86_32
1956	select RELOCATABLE
1957	---help---
1958	  This kernel feature allows a bzImage to be loaded directly
1959	  by EFI firmware without the use of a bootloader.
1960
1961	  See Documentation/admin-guide/efi-stub.rst for more information.
1962
1963config EFI_MIXED
1964	bool "EFI mixed-mode support"
1965	depends on EFI_STUB && X86_64
1966	---help---
1967	   Enabling this feature allows a 64-bit kernel to be booted
1968	   on a 32-bit firmware, provided that your CPU supports 64-bit
1969	   mode.
1970
1971	   Note that it is not possible to boot a mixed-mode enabled
1972	   kernel via the EFI boot stub - a bootloader that supports
1973	   the EFI handover protocol must be used.
1974
1975	   If unsure, say N.
1976
1977config SECCOMP
1978	def_bool y
1979	prompt "Enable seccomp to safely compute untrusted bytecode"
1980	---help---
1981	  This kernel feature is useful for number crunching applications
1982	  that may need to compute untrusted bytecode during their
1983	  execution. By using pipes or other transports made available to
1984	  the process as file descriptors supporting the read/write
1985	  syscalls, it's possible to isolate those applications in
1986	  their own address space using seccomp. Once seccomp is
1987	  enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1988	  and the task is only allowed to execute a few safe syscalls
1989	  defined by each seccomp mode.
1990
1991	  If unsure, say Y. Only embedded should say N here.
1992
1993source "kernel/Kconfig.hz"
1994
1995config KEXEC
1996	bool "kexec system call"
1997	select KEXEC_CORE
1998	---help---
1999	  kexec is a system call that implements the ability to shutdown your
2000	  current kernel, and to start another kernel.  It is like a reboot
2001	  but it is independent of the system firmware.   And like a reboot
2002	  you can start any kernel with it, not just Linux.
2003
2004	  The name comes from the similarity to the exec system call.
2005
2006	  It is an ongoing process to be certain the hardware in a machine
2007	  is properly shutdown, so do not be surprised if this code does not
2008	  initially work for you.  As of this writing the exact hardware
2009	  interface is strongly in flux, so no good recommendation can be
2010	  made.
2011
2012config KEXEC_FILE
2013	bool "kexec file based system call"
2014	select KEXEC_CORE
2015	select BUILD_BIN2C
2016	depends on X86_64
2017	depends on CRYPTO=y
2018	depends on CRYPTO_SHA256=y
2019	---help---
2020	  This is new version of kexec system call. This system call is
2021	  file based and takes file descriptors as system call argument
2022	  for kernel and initramfs as opposed to list of segments as
2023	  accepted by previous system call.
2024
2025config ARCH_HAS_KEXEC_PURGATORY
2026	def_bool KEXEC_FILE
2027
2028config KEXEC_SIG
2029	bool "Verify kernel signature during kexec_file_load() syscall"
2030	depends on KEXEC_FILE
2031	---help---
2032
2033	  This option makes the kexec_file_load() syscall check for a valid
2034	  signature of the kernel image.  The image can still be loaded without
2035	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2036	  there's a signature that we can check, then it must be valid.
2037
2038	  In addition to this option, you need to enable signature
2039	  verification for the corresponding kernel image type being
2040	  loaded in order for this to work.
2041
2042config KEXEC_SIG_FORCE
2043	bool "Require a valid signature in kexec_file_load() syscall"
2044	depends on KEXEC_SIG
2045	---help---
2046	  This option makes kernel signature verification mandatory for
2047	  the kexec_file_load() syscall.
2048
2049config KEXEC_BZIMAGE_VERIFY_SIG
2050	bool "Enable bzImage signature verification support"
2051	depends on KEXEC_SIG
2052	depends on SIGNED_PE_FILE_VERIFICATION
2053	select SYSTEM_TRUSTED_KEYRING
2054	---help---
2055	  Enable bzImage signature verification support.
2056
2057config CRASH_DUMP
2058	bool "kernel crash dumps"
2059	depends on X86_64 || (X86_32 && HIGHMEM)
2060	---help---
2061	  Generate crash dump after being started by kexec.
2062	  This should be normally only set in special crash dump kernels
2063	  which are loaded in the main kernel with kexec-tools into
2064	  a specially reserved region and then later executed after
2065	  a crash by kdump/kexec. The crash dump kernel must be compiled
2066	  to a memory address not used by the main kernel or BIOS using
2067	  PHYSICAL_START, or it must be built as a relocatable image
2068	  (CONFIG_RELOCATABLE=y).
2069	  For more details see Documentation/admin-guide/kdump/kdump.rst
2070
2071config KEXEC_JUMP
2072	bool "kexec jump"
2073	depends on KEXEC && HIBERNATION
2074	---help---
2075	  Jump between original kernel and kexeced kernel and invoke
2076	  code in physical address mode via KEXEC
2077
2078config PHYSICAL_START
2079	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2080	default "0x1000000"
2081	---help---
2082	  This gives the physical address where the kernel is loaded.
2083
2084	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2085	  bzImage will decompress itself to above physical address and
2086	  run from there. Otherwise, bzImage will run from the address where
2087	  it has been loaded by the boot loader and will ignore above physical
2088	  address.
2089
2090	  In normal kdump cases one does not have to set/change this option
2091	  as now bzImage can be compiled as a completely relocatable image
2092	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2093	  address. This option is mainly useful for the folks who don't want
2094	  to use a bzImage for capturing the crash dump and want to use a
2095	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2096	  to be specifically compiled to run from a specific memory area
2097	  (normally a reserved region) and this option comes handy.
2098
2099	  So if you are using bzImage for capturing the crash dump,
2100	  leave the value here unchanged to 0x1000000 and set
2101	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2102	  for capturing the crash dump change this value to start of
2103	  the reserved region.  In other words, it can be set based on
2104	  the "X" value as specified in the "crashkernel=YM@XM"
2105	  command line boot parameter passed to the panic-ed
2106	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2107	  for more details about crash dumps.
2108
2109	  Usage of bzImage for capturing the crash dump is recommended as
2110	  one does not have to build two kernels. Same kernel can be used
2111	  as production kernel and capture kernel. Above option should have
2112	  gone away after relocatable bzImage support is introduced. But it
2113	  is present because there are users out there who continue to use
2114	  vmlinux for dump capture. This option should go away down the
2115	  line.
2116
2117	  Don't change this unless you know what you are doing.
2118
2119config RELOCATABLE
2120	bool "Build a relocatable kernel"
2121	default y
2122	---help---
2123	  This builds a kernel image that retains relocation information
2124	  so it can be loaded someplace besides the default 1MB.
2125	  The relocations tend to make the kernel binary about 10% larger,
2126	  but are discarded at runtime.
2127
2128	  One use is for the kexec on panic case where the recovery kernel
2129	  must live at a different physical address than the primary
2130	  kernel.
2131
2132	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2133	  it has been loaded at and the compile time physical address
2134	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2135
2136config RANDOMIZE_BASE
2137	bool "Randomize the address of the kernel image (KASLR)"
2138	depends on RELOCATABLE
2139	default y
2140	---help---
2141	  In support of Kernel Address Space Layout Randomization (KASLR),
2142	  this randomizes the physical address at which the kernel image
2143	  is decompressed and the virtual address where the kernel
2144	  image is mapped, as a security feature that deters exploit
2145	  attempts relying on knowledge of the location of kernel
2146	  code internals.
2147
2148	  On 64-bit, the kernel physical and virtual addresses are
2149	  randomized separately. The physical address will be anywhere
2150	  between 16MB and the top of physical memory (up to 64TB). The
2151	  virtual address will be randomized from 16MB up to 1GB (9 bits
2152	  of entropy). Note that this also reduces the memory space
2153	  available to kernel modules from 1.5GB to 1GB.
2154
2155	  On 32-bit, the kernel physical and virtual addresses are
2156	  randomized together. They will be randomized from 16MB up to
2157	  512MB (8 bits of entropy).
2158
2159	  Entropy is generated using the RDRAND instruction if it is
2160	  supported. If RDTSC is supported, its value is mixed into
2161	  the entropy pool as well. If neither RDRAND nor RDTSC are
2162	  supported, then entropy is read from the i8254 timer. The
2163	  usable entropy is limited by the kernel being built using
2164	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2165	  minimum of 2MB. As a result, only 10 bits of entropy are
2166	  theoretically possible, but the implementations are further
2167	  limited due to memory layouts.
2168
2169	  If unsure, say Y.
2170
2171# Relocation on x86 needs some additional build support
2172config X86_NEED_RELOCS
2173	def_bool y
2174	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2175
2176config PHYSICAL_ALIGN
2177	hex "Alignment value to which kernel should be aligned"
2178	default "0x200000"
2179	range 0x2000 0x1000000 if X86_32
2180	range 0x200000 0x1000000 if X86_64
2181	---help---
2182	  This value puts the alignment restrictions on physical address
2183	  where kernel is loaded and run from. Kernel is compiled for an
2184	  address which meets above alignment restriction.
2185
2186	  If bootloader loads the kernel at a non-aligned address and
2187	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2188	  address aligned to above value and run from there.
2189
2190	  If bootloader loads the kernel at a non-aligned address and
2191	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2192	  load address and decompress itself to the address it has been
2193	  compiled for and run from there. The address for which kernel is
2194	  compiled already meets above alignment restrictions. Hence the
2195	  end result is that kernel runs from a physical address meeting
2196	  above alignment restrictions.
2197
2198	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2199	  this value must be a multiple of 0x200000.
2200
2201	  Don't change this unless you know what you are doing.
2202
2203config DYNAMIC_MEMORY_LAYOUT
2204	bool
2205	---help---
2206	  This option makes base addresses of vmalloc and vmemmap as well as
2207	  __PAGE_OFFSET movable during boot.
2208
2209config RANDOMIZE_MEMORY
2210	bool "Randomize the kernel memory sections"
2211	depends on X86_64
2212	depends on RANDOMIZE_BASE
2213	select DYNAMIC_MEMORY_LAYOUT
2214	default RANDOMIZE_BASE
2215	---help---
2216	   Randomizes the base virtual address of kernel memory sections
2217	   (physical memory mapping, vmalloc & vmemmap). This security feature
2218	   makes exploits relying on predictable memory locations less reliable.
2219
2220	   The order of allocations remains unchanged. Entropy is generated in
2221	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2222	   configuration have in average 30,000 different possible virtual
2223	   addresses for each memory section.
2224
2225	   If unsure, say Y.
2226
2227config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2228	hex "Physical memory mapping padding" if EXPERT
2229	depends on RANDOMIZE_MEMORY
2230	default "0xa" if MEMORY_HOTPLUG
2231	default "0x0"
2232	range 0x1 0x40 if MEMORY_HOTPLUG
2233	range 0x0 0x40
2234	---help---
2235	   Define the padding in terabytes added to the existing physical
2236	   memory size during kernel memory randomization. It is useful
2237	   for memory hotplug support but reduces the entropy available for
2238	   address randomization.
2239
2240	   If unsure, leave at the default value.
2241
2242config HOTPLUG_CPU
2243	def_bool y
2244	depends on SMP
2245
2246config BOOTPARAM_HOTPLUG_CPU0
2247	bool "Set default setting of cpu0_hotpluggable"
2248	depends on HOTPLUG_CPU
2249	---help---
2250	  Set whether default state of cpu0_hotpluggable is on or off.
2251
2252	  Say Y here to enable CPU0 hotplug by default. If this switch
2253	  is turned on, there is no need to give cpu0_hotplug kernel
2254	  parameter and the CPU0 hotplug feature is enabled by default.
2255
2256	  Please note: there are two known CPU0 dependencies if you want
2257	  to enable the CPU0 hotplug feature either by this switch or by
2258	  cpu0_hotplug kernel parameter.
2259
2260	  First, resume from hibernate or suspend always starts from CPU0.
2261	  So hibernate and suspend are prevented if CPU0 is offline.
2262
2263	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2264	  offline if any interrupt can not migrate out of CPU0. There may
2265	  be other CPU0 dependencies.
2266
2267	  Please make sure the dependencies are under your control before
2268	  you enable this feature.
2269
2270	  Say N if you don't want to enable CPU0 hotplug feature by default.
2271	  You still can enable the CPU0 hotplug feature at boot by kernel
2272	  parameter cpu0_hotplug.
2273
2274config DEBUG_HOTPLUG_CPU0
2275	def_bool n
2276	prompt "Debug CPU0 hotplug"
2277	depends on HOTPLUG_CPU
2278	---help---
2279	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2280	  soon as possible and boots up userspace with CPU0 offlined. User
2281	  can online CPU0 back after boot time.
2282
2283	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2284	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2285	  compilation or giving cpu0_hotplug kernel parameter at boot.
2286
2287	  If unsure, say N.
2288
2289config COMPAT_VDSO
2290	def_bool n
2291	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2292	depends on COMPAT_32
2293	---help---
2294	  Certain buggy versions of glibc will crash if they are
2295	  presented with a 32-bit vDSO that is not mapped at the address
2296	  indicated in its segment table.
2297
2298	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2299	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2300	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2301	  the only released version with the bug, but OpenSUSE 9
2302	  contains a buggy "glibc 2.3.2".
2303
2304	  The symptom of the bug is that everything crashes on startup, saying:
2305	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2306
2307	  Saying Y here changes the default value of the vdso32 boot
2308	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2309	  This works around the glibc bug but hurts performance.
2310
2311	  If unsure, say N: if you are compiling your own kernel, you
2312	  are unlikely to be using a buggy version of glibc.
2313
2314choice
2315	prompt "vsyscall table for legacy applications"
2316	depends on X86_64
2317	default LEGACY_VSYSCALL_XONLY
2318	help
2319	  Legacy user code that does not know how to find the vDSO expects
2320	  to be able to issue three syscalls by calling fixed addresses in
2321	  kernel space. Since this location is not randomized with ASLR,
2322	  it can be used to assist security vulnerability exploitation.
2323
2324	  This setting can be changed at boot time via the kernel command
2325	  line parameter vsyscall=[emulate|xonly|none].
2326
2327	  On a system with recent enough glibc (2.14 or newer) and no
2328	  static binaries, you can say None without a performance penalty
2329	  to improve security.
2330
2331	  If unsure, select "Emulate execution only".
2332
2333	config LEGACY_VSYSCALL_EMULATE
2334		bool "Full emulation"
2335		help
2336		  The kernel traps and emulates calls into the fixed vsyscall
2337		  address mapping. This makes the mapping non-executable, but
2338		  it still contains readable known contents, which could be
2339		  used in certain rare security vulnerability exploits. This
2340		  configuration is recommended when using legacy userspace
2341		  that still uses vsyscalls along with legacy binary
2342		  instrumentation tools that require code to be readable.
2343
2344		  An example of this type of legacy userspace is running
2345		  Pin on an old binary that still uses vsyscalls.
2346
2347	config LEGACY_VSYSCALL_XONLY
2348		bool "Emulate execution only"
2349		help
2350		  The kernel traps and emulates calls into the fixed vsyscall
2351		  address mapping and does not allow reads.  This
2352		  configuration is recommended when userspace might use the
2353		  legacy vsyscall area but support for legacy binary
2354		  instrumentation of legacy code is not needed.  It mitigates
2355		  certain uses of the vsyscall area as an ASLR-bypassing
2356		  buffer.
2357
2358	config LEGACY_VSYSCALL_NONE
2359		bool "None"
2360		help
2361		  There will be no vsyscall mapping at all. This will
2362		  eliminate any risk of ASLR bypass due to the vsyscall
2363		  fixed address mapping. Attempts to use the vsyscalls
2364		  will be reported to dmesg, so that either old or
2365		  malicious userspace programs can be identified.
2366
2367endchoice
2368
2369config CMDLINE_BOOL
2370	bool "Built-in kernel command line"
2371	---help---
2372	  Allow for specifying boot arguments to the kernel at
2373	  build time.  On some systems (e.g. embedded ones), it is
2374	  necessary or convenient to provide some or all of the
2375	  kernel boot arguments with the kernel itself (that is,
2376	  to not rely on the boot loader to provide them.)
2377
2378	  To compile command line arguments into the kernel,
2379	  set this option to 'Y', then fill in the
2380	  boot arguments in CONFIG_CMDLINE.
2381
2382	  Systems with fully functional boot loaders (i.e. non-embedded)
2383	  should leave this option set to 'N'.
2384
2385config CMDLINE
2386	string "Built-in kernel command string"
2387	depends on CMDLINE_BOOL
2388	default ""
2389	---help---
2390	  Enter arguments here that should be compiled into the kernel
2391	  image and used at boot time.  If the boot loader provides a
2392	  command line at boot time, it is appended to this string to
2393	  form the full kernel command line, when the system boots.
2394
2395	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2396	  change this behavior.
2397
2398	  In most cases, the command line (whether built-in or provided
2399	  by the boot loader) should specify the device for the root
2400	  file system.
2401
2402config CMDLINE_OVERRIDE
2403	bool "Built-in command line overrides boot loader arguments"
2404	depends on CMDLINE_BOOL && CMDLINE != ""
2405	---help---
2406	  Set this option to 'Y' to have the kernel ignore the boot loader
2407	  command line, and use ONLY the built-in command line.
2408
2409	  This is used to work around broken boot loaders.  This should
2410	  be set to 'N' under normal conditions.
2411
2412config MODIFY_LDT_SYSCALL
2413	bool "Enable the LDT (local descriptor table)" if EXPERT
2414	default y
2415	---help---
2416	  Linux can allow user programs to install a per-process x86
2417	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2418	  call.  This is required to run 16-bit or segmented code such as
2419	  DOSEMU or some Wine programs.  It is also used by some very old
2420	  threading libraries.
2421
2422	  Enabling this feature adds a small amount of overhead to
2423	  context switches and increases the low-level kernel attack
2424	  surface.  Disabling it removes the modify_ldt(2) system call.
2425
2426	  Saying 'N' here may make sense for embedded or server kernels.
2427
2428source "kernel/livepatch/Kconfig"
2429
2430endmenu
2431
2432config ARCH_HAS_ADD_PAGES
2433	def_bool y
2434	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2435
2436config ARCH_ENABLE_MEMORY_HOTPLUG
2437	def_bool y
2438	depends on X86_64 || (X86_32 && HIGHMEM)
2439
2440config ARCH_ENABLE_MEMORY_HOTREMOVE
2441	def_bool y
2442	depends on MEMORY_HOTPLUG
2443
2444config USE_PERCPU_NUMA_NODE_ID
2445	def_bool y
2446	depends on NUMA
2447
2448config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2449	def_bool y
2450	depends on X86_64 || X86_PAE
2451
2452config ARCH_ENABLE_HUGEPAGE_MIGRATION
2453	def_bool y
2454	depends on X86_64 && HUGETLB_PAGE && MIGRATION
2455
2456config ARCH_ENABLE_THP_MIGRATION
2457	def_bool y
2458	depends on X86_64 && TRANSPARENT_HUGEPAGE
2459
2460menu "Power management and ACPI options"
2461
2462config ARCH_HIBERNATION_HEADER
2463	def_bool y
2464	depends on HIBERNATION
2465
2466source "kernel/power/Kconfig"
2467
2468source "drivers/acpi/Kconfig"
2469
2470source "drivers/sfi/Kconfig"
2471
2472config X86_APM_BOOT
2473	def_bool y
2474	depends on APM
2475
2476menuconfig APM
2477	tristate "APM (Advanced Power Management) BIOS support"
2478	depends on X86_32 && PM_SLEEP
2479	---help---
2480	  APM is a BIOS specification for saving power using several different
2481	  techniques. This is mostly useful for battery powered laptops with
2482	  APM compliant BIOSes. If you say Y here, the system time will be
2483	  reset after a RESUME operation, the /proc/apm device will provide
2484	  battery status information, and user-space programs will receive
2485	  notification of APM "events" (e.g. battery status change).
2486
2487	  If you select "Y" here, you can disable actual use of the APM
2488	  BIOS by passing the "apm=off" option to the kernel at boot time.
2489
2490	  Note that the APM support is almost completely disabled for
2491	  machines with more than one CPU.
2492
2493	  In order to use APM, you will need supporting software. For location
2494	  and more information, read <file:Documentation/power/apm-acpi.rst>
2495	  and the Battery Powered Linux mini-HOWTO, available from
2496	  <http://www.tldp.org/docs.html#howto>.
2497
2498	  This driver does not spin down disk drives (see the hdparm(8)
2499	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2500	  VESA-compliant "green" monitors.
2501
2502	  This driver does not support the TI 4000M TravelMate and the ACER
2503	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2504	  desktop machines also don't have compliant BIOSes, and this driver
2505	  may cause those machines to panic during the boot phase.
2506
2507	  Generally, if you don't have a battery in your machine, there isn't
2508	  much point in using this driver and you should say N. If you get
2509	  random kernel OOPSes or reboots that don't seem to be related to
2510	  anything, try disabling/enabling this option (or disabling/enabling
2511	  APM in your BIOS).
2512
2513	  Some other things you should try when experiencing seemingly random,
2514	  "weird" problems:
2515
2516	  1) make sure that you have enough swap space and that it is
2517	  enabled.
2518	  2) pass the "no-hlt" option to the kernel
2519	  3) switch on floating point emulation in the kernel and pass
2520	  the "no387" option to the kernel
2521	  4) pass the "floppy=nodma" option to the kernel
2522	  5) pass the "mem=4M" option to the kernel (thereby disabling
2523	  all but the first 4 MB of RAM)
2524	  6) make sure that the CPU is not over clocked.
2525	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2526	  8) disable the cache from your BIOS settings
2527	  9) install a fan for the video card or exchange video RAM
2528	  10) install a better fan for the CPU
2529	  11) exchange RAM chips
2530	  12) exchange the motherboard.
2531
2532	  To compile this driver as a module, choose M here: the
2533	  module will be called apm.
2534
2535if APM
2536
2537config APM_IGNORE_USER_SUSPEND
2538	bool "Ignore USER SUSPEND"
2539	---help---
2540	  This option will ignore USER SUSPEND requests. On machines with a
2541	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2542	  series notebooks, it is necessary to say Y because of a BIOS bug.
2543
2544config APM_DO_ENABLE
2545	bool "Enable PM at boot time"
2546	---help---
2547	  Enable APM features at boot time. From page 36 of the APM BIOS
2548	  specification: "When disabled, the APM BIOS does not automatically
2549	  power manage devices, enter the Standby State, enter the Suspend
2550	  State, or take power saving steps in response to CPU Idle calls."
2551	  This driver will make CPU Idle calls when Linux is idle (unless this
2552	  feature is turned off -- see "Do CPU IDLE calls", below). This
2553	  should always save battery power, but more complicated APM features
2554	  will be dependent on your BIOS implementation. You may need to turn
2555	  this option off if your computer hangs at boot time when using APM
2556	  support, or if it beeps continuously instead of suspending. Turn
2557	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2558	  T400CDT. This is off by default since most machines do fine without
2559	  this feature.
2560
2561config APM_CPU_IDLE
2562	depends on CPU_IDLE
2563	bool "Make CPU Idle calls when idle"
2564	---help---
2565	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2566	  On some machines, this can activate improved power savings, such as
2567	  a slowed CPU clock rate, when the machine is idle. These idle calls
2568	  are made after the idle loop has run for some length of time (e.g.,
2569	  333 mS). On some machines, this will cause a hang at boot time or
2570	  whenever the CPU becomes idle. (On machines with more than one CPU,
2571	  this option does nothing.)
2572
2573config APM_DISPLAY_BLANK
2574	bool "Enable console blanking using APM"
2575	---help---
2576	  Enable console blanking using the APM. Some laptops can use this to
2577	  turn off the LCD backlight when the screen blanker of the Linux
2578	  virtual console blanks the screen. Note that this is only used by
2579	  the virtual console screen blanker, and won't turn off the backlight
2580	  when using the X Window system. This also doesn't have anything to
2581	  do with your VESA-compliant power-saving monitor. Further, this
2582	  option doesn't work for all laptops -- it might not turn off your
2583	  backlight at all, or it might print a lot of errors to the console,
2584	  especially if you are using gpm.
2585
2586config APM_ALLOW_INTS
2587	bool "Allow interrupts during APM BIOS calls"
2588	---help---
2589	  Normally we disable external interrupts while we are making calls to
2590	  the APM BIOS as a measure to lessen the effects of a badly behaving
2591	  BIOS implementation.  The BIOS should reenable interrupts if it
2592	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2593	  many of the newer IBM Thinkpads.  If you experience hangs when you
2594	  suspend, try setting this to Y.  Otherwise, say N.
2595
2596endif # APM
2597
2598source "drivers/cpufreq/Kconfig"
2599
2600source "drivers/cpuidle/Kconfig"
2601
2602source "drivers/idle/Kconfig"
2603
2604endmenu
2605
2606
2607menu "Bus options (PCI etc.)"
2608
2609choice
2610	prompt "PCI access mode"
2611	depends on X86_32 && PCI
2612	default PCI_GOANY
2613	---help---
2614	  On PCI systems, the BIOS can be used to detect the PCI devices and
2615	  determine their configuration. However, some old PCI motherboards
2616	  have BIOS bugs and may crash if this is done. Also, some embedded
2617	  PCI-based systems don't have any BIOS at all. Linux can also try to
2618	  detect the PCI hardware directly without using the BIOS.
2619
2620	  With this option, you can specify how Linux should detect the
2621	  PCI devices. If you choose "BIOS", the BIOS will be used,
2622	  if you choose "Direct", the BIOS won't be used, and if you
2623	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2624	  If you choose "Any", the kernel will try MMCONFIG, then the
2625	  direct access method and falls back to the BIOS if that doesn't
2626	  work. If unsure, go with the default, which is "Any".
2627
2628config PCI_GOBIOS
2629	bool "BIOS"
2630
2631config PCI_GOMMCONFIG
2632	bool "MMConfig"
2633
2634config PCI_GODIRECT
2635	bool "Direct"
2636
2637config PCI_GOOLPC
2638	bool "OLPC XO-1"
2639	depends on OLPC
2640
2641config PCI_GOANY
2642	bool "Any"
2643
2644endchoice
2645
2646config PCI_BIOS
2647	def_bool y
2648	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2649
2650# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2651config PCI_DIRECT
2652	def_bool y
2653	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2654
2655config PCI_MMCONFIG
2656	bool "Support mmconfig PCI config space access" if X86_64
2657	default y
2658	depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2659	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2660
2661config PCI_OLPC
2662	def_bool y
2663	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2664
2665config PCI_XEN
2666	def_bool y
2667	depends on PCI && XEN
2668	select SWIOTLB_XEN
2669
2670config MMCONF_FAM10H
2671	def_bool y
2672	depends on X86_64 && PCI_MMCONFIG && ACPI
2673
2674config PCI_CNB20LE_QUIRK
2675	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2676	depends on PCI
2677	help
2678	  Read the PCI windows out of the CNB20LE host bridge. This allows
2679	  PCI hotplug to work on systems with the CNB20LE chipset which do
2680	  not have ACPI.
2681
2682	  There's no public spec for this chipset, and this functionality
2683	  is known to be incomplete.
2684
2685	  You should say N unless you know you need this.
2686
2687config ISA_BUS
2688	bool "ISA bus support on modern systems" if EXPERT
2689	help
2690	  Expose ISA bus device drivers and options available for selection and
2691	  configuration. Enable this option if your target machine has an ISA
2692	  bus. ISA is an older system, displaced by PCI and newer bus
2693	  architectures -- if your target machine is modern, it probably does
2694	  not have an ISA bus.
2695
2696	  If unsure, say N.
2697
2698# x86_64 have no ISA slots, but can have ISA-style DMA.
2699config ISA_DMA_API
2700	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2701	default y
2702	help
2703	  Enables ISA-style DMA support for devices requiring such controllers.
2704	  If unsure, say Y.
2705
2706if X86_32
2707
2708config ISA
2709	bool "ISA support"
2710	---help---
2711	  Find out whether you have ISA slots on your motherboard.  ISA is the
2712	  name of a bus system, i.e. the way the CPU talks to the other stuff
2713	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2714	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2715	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2716
2717config SCx200
2718	tristate "NatSemi SCx200 support"
2719	---help---
2720	  This provides basic support for National Semiconductor's
2721	  (now AMD's) Geode processors.  The driver probes for the
2722	  PCI-IDs of several on-chip devices, so its a good dependency
2723	  for other scx200_* drivers.
2724
2725	  If compiled as a module, the driver is named scx200.
2726
2727config SCx200HR_TIMER
2728	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2729	depends on SCx200
2730	default y
2731	---help---
2732	  This driver provides a clocksource built upon the on-chip
2733	  27MHz high-resolution timer.  Its also a workaround for
2734	  NSC Geode SC-1100's buggy TSC, which loses time when the
2735	  processor goes idle (as is done by the scheduler).  The
2736	  other workaround is idle=poll boot option.
2737
2738config OLPC
2739	bool "One Laptop Per Child support"
2740	depends on !X86_PAE
2741	select GPIOLIB
2742	select OF
2743	select OF_PROMTREE
2744	select IRQ_DOMAIN
2745	select OLPC_EC
2746	---help---
2747	  Add support for detecting the unique features of the OLPC
2748	  XO hardware.
2749
2750config OLPC_XO1_PM
2751	bool "OLPC XO-1 Power Management"
2752	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2753	---help---
2754	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2755
2756config OLPC_XO1_RTC
2757	bool "OLPC XO-1 Real Time Clock"
2758	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2759	---help---
2760	  Add support for the XO-1 real time clock, which can be used as a
2761	  programmable wakeup source.
2762
2763config OLPC_XO1_SCI
2764	bool "OLPC XO-1 SCI extras"
2765	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2766	depends on INPUT=y
2767	select POWER_SUPPLY
2768	---help---
2769	  Add support for SCI-based features of the OLPC XO-1 laptop:
2770	   - EC-driven system wakeups
2771	   - Power button
2772	   - Ebook switch
2773	   - Lid switch
2774	   - AC adapter status updates
2775	   - Battery status updates
2776
2777config OLPC_XO15_SCI
2778	bool "OLPC XO-1.5 SCI extras"
2779	depends on OLPC && ACPI
2780	select POWER_SUPPLY
2781	---help---
2782	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2783	   - EC-driven system wakeups
2784	   - AC adapter status updates
2785	   - Battery status updates
2786
2787config ALIX
2788	bool "PCEngines ALIX System Support (LED setup)"
2789	select GPIOLIB
2790	---help---
2791	  This option enables system support for the PCEngines ALIX.
2792	  At present this just sets up LEDs for GPIO control on
2793	  ALIX2/3/6 boards.  However, other system specific setup should
2794	  get added here.
2795
2796	  Note: You must still enable the drivers for GPIO and LED support
2797	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2798
2799	  Note: You have to set alix.force=1 for boards with Award BIOS.
2800
2801config NET5501
2802	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2803	select GPIOLIB
2804	---help---
2805	  This option enables system support for the Soekris Engineering net5501.
2806
2807config GEOS
2808	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2809	select GPIOLIB
2810	depends on DMI
2811	---help---
2812	  This option enables system support for the Traverse Technologies GEOS.
2813
2814config TS5500
2815	bool "Technologic Systems TS-5500 platform support"
2816	depends on MELAN
2817	select CHECK_SIGNATURE
2818	select NEW_LEDS
2819	select LEDS_CLASS
2820	---help---
2821	  This option enables system support for the Technologic Systems TS-5500.
2822
2823endif # X86_32
2824
2825config AMD_NB
2826	def_bool y
2827	depends on CPU_SUP_AMD && PCI
2828
2829config X86_SYSFB
2830	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2831	help
2832	  Firmwares often provide initial graphics framebuffers so the BIOS,
2833	  bootloader or kernel can show basic video-output during boot for
2834	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2835	  Extensions and EFI-framebuffers for this, which are mostly limited
2836	  to x86.
2837	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2838	  framebuffers so the new generic system-framebuffer drivers can be
2839	  used on x86. If the framebuffer is not compatible with the generic
2840	  modes, it is advertised as fallback platform framebuffer so legacy
2841	  drivers like efifb, vesafb and uvesafb can pick it up.
2842	  If this option is not selected, all system framebuffers are always
2843	  marked as fallback platform framebuffers as usual.
2844
2845	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2846	  not be able to pick up generic system framebuffers if this option
2847	  is selected. You are highly encouraged to enable simplefb as
2848	  replacement if you select this option. simplefb can correctly deal
2849	  with generic system framebuffers. But you should still keep vesafb
2850	  and others enabled as fallback if a system framebuffer is
2851	  incompatible with simplefb.
2852
2853	  If unsure, say Y.
2854
2855endmenu
2856
2857
2858menu "Binary Emulations"
2859
2860config IA32_EMULATION
2861	bool "IA32 Emulation"
2862	depends on X86_64
2863	select ARCH_WANT_OLD_COMPAT_IPC
2864	select BINFMT_ELF
2865	select COMPAT_BINFMT_ELF
2866	select COMPAT_OLD_SIGACTION
2867	---help---
2868	  Include code to run legacy 32-bit programs under a
2869	  64-bit kernel. You should likely turn this on, unless you're
2870	  100% sure that you don't have any 32-bit programs left.
2871
2872config IA32_AOUT
2873	tristate "IA32 a.out support"
2874	depends on IA32_EMULATION
2875	depends on BROKEN
2876	---help---
2877	  Support old a.out binaries in the 32bit emulation.
2878
2879config X86_X32
2880	bool "x32 ABI for 64-bit mode"
2881	depends on X86_64
2882	---help---
2883	  Include code to run binaries for the x32 native 32-bit ABI
2884	  for 64-bit processors.  An x32 process gets access to the
2885	  full 64-bit register file and wide data path while leaving
2886	  pointers at 32 bits for smaller memory footprint.
2887
2888	  You will need a recent binutils (2.22 or later) with
2889	  elf32_x86_64 support enabled to compile a kernel with this
2890	  option set.
2891
2892config COMPAT_32
2893	def_bool y
2894	depends on IA32_EMULATION || X86_32
2895	select HAVE_UID16
2896	select OLD_SIGSUSPEND3
2897
2898config COMPAT
2899	def_bool y
2900	depends on IA32_EMULATION || X86_X32
2901
2902if COMPAT
2903config COMPAT_FOR_U64_ALIGNMENT
2904	def_bool y
2905
2906config SYSVIPC_COMPAT
2907	def_bool y
2908	depends on SYSVIPC
2909endif
2910
2911endmenu
2912
2913
2914config HAVE_ATOMIC_IOMAP
2915	def_bool y
2916	depends on X86_32
2917
2918source "drivers/firmware/Kconfig"
2919
2920source "arch/x86/kvm/Kconfig"
2921
2922source "arch/x86/Kconfig.assembler"
2923