xref: /openbmc/linux/arch/x86/Kconfig (revision 6197e5b7)
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 GENERIC_VDSO_32
18	select HAVE_DEBUG_STACKOVERFLOW
19	select KMAP_LOCAL
20	select MODULES_USE_ELF_REL
21	select OLD_SIGACTION
22	select ARCH_SPLIT_ARG64
23
24config X86_64
25	def_bool y
26	depends on 64BIT
27	# Options that are inherently 64-bit kernel only:
28	select ARCH_HAS_GIGANTIC_PAGE
29	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30	select ARCH_USE_CMPXCHG_LOCKREF
31	select HAVE_ARCH_SOFT_DIRTY
32	select MODULES_USE_ELF_RELA
33	select NEED_DMA_MAP_STATE
34	select SWIOTLB
35	select ARCH_HAS_ELFCORE_COMPAT
36
37config FORCE_DYNAMIC_FTRACE
38	def_bool y
39	depends on X86_32
40	depends on FUNCTION_TRACER
41	select DYNAMIC_FTRACE
42	help
43	 We keep the static function tracing (!DYNAMIC_FTRACE) around
44	 in order to test the non static function tracing in the
45	 generic code, as other architectures still use it. But we
46	 only need to keep it around for x86_64. No need to keep it
47	 for x86_32. For x86_32, force DYNAMIC_FTRACE.
48#
49# Arch settings
50#
51# ( Note that options that are marked 'if X86_64' could in principle be
52#   ported to 32-bit as well. )
53#
54config X86
55	def_bool y
56	#
57	# Note: keep this list sorted alphabetically
58	#
59	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
60	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
61	select ARCH_32BIT_OFF_T			if X86_32
62	select ARCH_CLOCKSOURCE_INIT
63	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
64	select ARCH_HAS_DEBUG_VIRTUAL
65	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
66	select ARCH_HAS_DEVMEM_IS_ALLOWED
67	select ARCH_HAS_EARLY_DEBUG		if KGDB
68	select ARCH_HAS_ELF_RANDOMIZE
69	select ARCH_HAS_FAST_MULTIPLIER
70	select ARCH_HAS_FILTER_PGPROT
71	select ARCH_HAS_FORTIFY_SOURCE
72	select ARCH_HAS_GCOV_PROFILE_ALL
73	select ARCH_HAS_KCOV			if X86_64 && STACK_VALIDATION
74	select ARCH_HAS_MEM_ENCRYPT
75	select ARCH_HAS_MEMBARRIER_SYNC_CORE
76	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
77	select ARCH_HAS_PMEM_API		if X86_64
78	select ARCH_HAS_PTE_DEVMAP		if X86_64
79	select ARCH_HAS_PTE_SPECIAL
80	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
81	select ARCH_HAS_COPY_MC			if X86_64
82	select ARCH_HAS_SET_MEMORY
83	select ARCH_HAS_SET_DIRECT_MAP
84	select ARCH_HAS_STRICT_KERNEL_RWX
85	select ARCH_HAS_STRICT_MODULE_RWX
86	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
87	select ARCH_HAS_SYSCALL_WRAPPER
88	select ARCH_HAS_UBSAN_SANITIZE_ALL
89	select ARCH_HAS_DEBUG_WX
90	select ARCH_HAVE_NMI_SAFE_CMPXCHG
91	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
92	select ARCH_MIGHT_HAVE_PC_PARPORT
93	select ARCH_MIGHT_HAVE_PC_SERIO
94	select ARCH_STACKWALK
95	select ARCH_SUPPORTS_ACPI
96	select ARCH_SUPPORTS_ATOMIC_RMW
97	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
98	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
99	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
100	select ARCH_USE_BUILTIN_BSWAP
101	select ARCH_USE_QUEUED_RWLOCKS
102	select ARCH_USE_QUEUED_SPINLOCKS
103	select ARCH_USE_SYM_ANNOTATIONS
104	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
105	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
106	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
107	select ARCH_WANT_HUGE_PMD_SHARE
108	select ARCH_WANT_LD_ORPHAN_WARN
109	select ARCH_WANTS_THP_SWAP		if X86_64
110	select BUILDTIME_TABLE_SORT
111	select CLKEVT_I8253
112	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
113	select CLOCKSOURCE_WATCHDOG
114	select DCACHE_WORD_ACCESS
115	select EDAC_ATOMIC_SCRUB
116	select EDAC_SUPPORT
117	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
118	select GENERIC_CLOCKEVENTS_MIN_ADJUST
119	select GENERIC_CMOS_UPDATE
120	select GENERIC_CPU_AUTOPROBE
121	select GENERIC_CPU_VULNERABILITIES
122	select GENERIC_EARLY_IOREMAP
123	select GENERIC_ENTRY
124	select GENERIC_FIND_FIRST_BIT
125	select GENERIC_IOMAP
126	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
127	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
128	select GENERIC_IRQ_MIGRATION		if SMP
129	select GENERIC_IRQ_PROBE
130	select GENERIC_IRQ_RESERVATION_MODE
131	select GENERIC_IRQ_SHOW
132	select GENERIC_PENDING_IRQ		if SMP
133	select GENERIC_PTDUMP
134	select GENERIC_SMP_IDLE_THREAD
135	select GENERIC_STRNCPY_FROM_USER
136	select GENERIC_STRNLEN_USER
137	select GENERIC_TIME_VSYSCALL
138	select GENERIC_GETTIMEOFDAY
139	select GENERIC_VDSO_TIME_NS
140	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
141	select HARDIRQS_SW_RESEND
142	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
143	select HAVE_ACPI_APEI			if ACPI
144	select HAVE_ACPI_APEI_NMI		if ACPI
145	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
146	select HAVE_ARCH_AUDITSYSCALL
147	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
148	select HAVE_ARCH_JUMP_LABEL
149	select HAVE_ARCH_JUMP_LABEL_RELATIVE
150	select HAVE_ARCH_KASAN			if X86_64
151	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
152	select HAVE_ARCH_KGDB
153	select HAVE_ARCH_MMAP_RND_BITS		if MMU
154	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
155	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
156	select HAVE_ARCH_PREL32_RELOCATIONS
157	select HAVE_ARCH_SECCOMP_FILTER
158	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
159	select HAVE_ARCH_STACKLEAK
160	select HAVE_ARCH_TRACEHOOK
161	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
162	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
163	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
164	select HAVE_ARCH_VMAP_STACK		if X86_64
165	select HAVE_ARCH_WITHIN_STACK_FRAMES
166	select HAVE_ASM_MODVERSIONS
167	select HAVE_CMPXCHG_DOUBLE
168	select HAVE_CMPXCHG_LOCAL
169	select HAVE_CONTEXT_TRACKING		if X86_64
170	select HAVE_CONTEXT_TRACKING_OFFSTACK	if HAVE_CONTEXT_TRACKING
171	select HAVE_C_RECORDMCOUNT
172	select HAVE_DEBUG_KMEMLEAK
173	select HAVE_DMA_CONTIGUOUS
174	select HAVE_DYNAMIC_FTRACE
175	select HAVE_DYNAMIC_FTRACE_WITH_REGS
176	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
177	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
178	select HAVE_EBPF_JIT
179	select HAVE_EFFICIENT_UNALIGNED_ACCESS
180	select HAVE_EISA
181	select HAVE_EXIT_THREAD
182	select HAVE_FAST_GUP
183	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
184	select HAVE_FTRACE_MCOUNT_RECORD
185	select HAVE_FUNCTION_GRAPH_TRACER
186	select HAVE_FUNCTION_TRACER
187	select HAVE_GCC_PLUGINS
188	select HAVE_HW_BREAKPOINT
189	select HAVE_IDE
190	select HAVE_IOREMAP_PROT
191	select HAVE_IRQ_TIME_ACCOUNTING
192	select HAVE_KERNEL_BZIP2
193	select HAVE_KERNEL_GZIP
194	select HAVE_KERNEL_LZ4
195	select HAVE_KERNEL_LZMA
196	select HAVE_KERNEL_LZO
197	select HAVE_KERNEL_XZ
198	select HAVE_KERNEL_ZSTD
199	select HAVE_KPROBES
200	select HAVE_KPROBES_ON_FTRACE
201	select HAVE_FUNCTION_ERROR_INJECTION
202	select HAVE_KRETPROBES
203	select HAVE_KVM
204	select HAVE_LIVEPATCH			if X86_64
205	select HAVE_MIXED_BREAKPOINTS_REGS
206	select HAVE_MOD_ARCH_SPECIFIC
207	select HAVE_MOVE_PMD
208	select HAVE_MOVE_PUD
209	select HAVE_NMI
210	select HAVE_OPTPROBES
211	select HAVE_PCSPKR_PLATFORM
212	select HAVE_PERF_EVENTS
213	select HAVE_PERF_EVENTS_NMI
214	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
215	select HAVE_PCI
216	select HAVE_PERF_REGS
217	select HAVE_PERF_USER_STACK_DUMP
218	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
219	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
220	select HAVE_REGS_AND_STACK_ACCESS_API
221	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
222	select HAVE_FUNCTION_ARG_ACCESS_API
223	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
224	select HAVE_STACK_VALIDATION		if X86_64
225	select HAVE_STATIC_CALL
226	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
227	select HAVE_PREEMPT_DYNAMIC
228	select HAVE_RSEQ
229	select HAVE_SYSCALL_TRACEPOINTS
230	select HAVE_UNSTABLE_SCHED_CLOCK
231	select HAVE_USER_RETURN_NOTIFIER
232	select HAVE_GENERIC_VDSO
233	select HOTPLUG_SMT			if SMP
234	select IRQ_FORCED_THREADING
235	select NEED_SG_DMA_LENGTH
236	select PCI_DOMAINS			if PCI
237	select PCI_LOCKLESS_CONFIG		if PCI
238	select PERF_EVENTS
239	select RTC_LIB
240	select RTC_MC146818_LIB
241	select SPARSE_IRQ
242	select SRCU
243	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
244	select SYSCTL_EXCEPTION_TRACE
245	select THREAD_INFO_IN_TASK
246	select USER_STACKTRACE_SUPPORT
247	select VIRT_TO_BUS
248	select HAVE_ARCH_KCSAN			if X86_64
249	select X86_FEATURE_NAMES		if PROC_FS
250	select PROC_PID_ARCH_STATUS		if PROC_FS
251	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
252
253config INSTRUCTION_DECODER
254	def_bool y
255	depends on KPROBES || PERF_EVENTS || UPROBES
256
257config OUTPUT_FORMAT
258	string
259	default "elf32-i386" if X86_32
260	default "elf64-x86-64" if X86_64
261
262config LOCKDEP_SUPPORT
263	def_bool y
264
265config STACKTRACE_SUPPORT
266	def_bool y
267
268config MMU
269	def_bool y
270
271config ARCH_MMAP_RND_BITS_MIN
272	default 28 if 64BIT
273	default 8
274
275config ARCH_MMAP_RND_BITS_MAX
276	default 32 if 64BIT
277	default 16
278
279config ARCH_MMAP_RND_COMPAT_BITS_MIN
280	default 8
281
282config ARCH_MMAP_RND_COMPAT_BITS_MAX
283	default 16
284
285config SBUS
286	bool
287
288config GENERIC_ISA_DMA
289	def_bool y
290	depends on ISA_DMA_API
291
292config GENERIC_BUG
293	def_bool y
294	depends on BUG
295	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
296
297config GENERIC_BUG_RELATIVE_POINTERS
298	bool
299
300config ARCH_MAY_HAVE_PC_FDC
301	def_bool y
302	depends on ISA_DMA_API
303
304config GENERIC_CALIBRATE_DELAY
305	def_bool y
306
307config ARCH_HAS_CPU_RELAX
308	def_bool y
309
310config ARCH_HAS_CACHE_LINE_SIZE
311	def_bool y
312
313config ARCH_HAS_FILTER_PGPROT
314	def_bool y
315
316config HAVE_SETUP_PER_CPU_AREA
317	def_bool y
318
319config NEED_PER_CPU_EMBED_FIRST_CHUNK
320	def_bool y
321
322config NEED_PER_CPU_PAGE_FIRST_CHUNK
323	def_bool y
324
325config ARCH_HIBERNATION_POSSIBLE
326	def_bool y
327
328config ARCH_SUSPEND_POSSIBLE
329	def_bool y
330
331config ARCH_WANT_GENERAL_HUGETLB
332	def_bool y
333
334config ZONE_DMA32
335	def_bool y if X86_64
336
337config AUDIT_ARCH
338	def_bool y if X86_64
339
340config KASAN_SHADOW_OFFSET
341	hex
342	depends on KASAN
343	default 0xdffffc0000000000
344
345config HAVE_INTEL_TXT
346	def_bool y
347	depends on INTEL_IOMMU && ACPI
348
349config X86_32_SMP
350	def_bool y
351	depends on X86_32 && SMP
352
353config X86_64_SMP
354	def_bool y
355	depends on X86_64 && SMP
356
357config X86_32_LAZY_GS
358	def_bool y
359	depends on X86_32 && !STACKPROTECTOR
360
361config ARCH_SUPPORTS_UPROBES
362	def_bool y
363
364config FIX_EARLYCON_MEM
365	def_bool y
366
367config DYNAMIC_PHYSICAL_MASK
368	bool
369
370config PGTABLE_LEVELS
371	int
372	default 5 if X86_5LEVEL
373	default 4 if X86_64
374	default 3 if X86_PAE
375	default 2
376
377config CC_HAS_SANE_STACKPROTECTOR
378	bool
379	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
380	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
381	help
382	   We have to make sure stack protector is unconditionally disabled if
383	   the compiler produces broken code.
384
385menu "Processor type and features"
386
387config ZONE_DMA
388	bool "DMA memory allocation support" if EXPERT
389	default y
390	help
391	  DMA memory allocation support allows devices with less than 32-bit
392	  addressing to allocate within the first 16MB of address space.
393	  Disable if no such devices will be used.
394
395	  If unsure, say Y.
396
397config SMP
398	bool "Symmetric multi-processing support"
399	help
400	  This enables support for systems with more than one CPU. If you have
401	  a system with only one CPU, say N. If you have a system with more
402	  than one CPU, say Y.
403
404	  If you say N here, the kernel will run on uni- and multiprocessor
405	  machines, but will use only one CPU of a multiprocessor machine. If
406	  you say Y here, the kernel will run on many, but not all,
407	  uniprocessor machines. On a uniprocessor machine, the kernel
408	  will run faster if you say N here.
409
410	  Note that if you say Y here and choose architecture "586" or
411	  "Pentium" under "Processor family", the kernel will not work on 486
412	  architectures. Similarly, multiprocessor kernels for the "PPro"
413	  architecture may not work on all Pentium based boards.
414
415	  People using multiprocessor machines who say Y here should also say
416	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
417	  Management" code will be disabled if you say Y here.
418
419	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
420	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
421	  <http://www.tldp.org/docs.html#howto>.
422
423	  If you don't know what to do here, say N.
424
425config X86_FEATURE_NAMES
426	bool "Processor feature human-readable names" if EMBEDDED
427	default y
428	help
429	  This option compiles in a table of x86 feature bits and corresponding
430	  names.  This is required to support /proc/cpuinfo and a few kernel
431	  messages.  You can disable this to save space, at the expense of
432	  making those few kernel messages show numeric feature bits instead.
433
434	  If in doubt, say Y.
435
436config X86_X2APIC
437	bool "Support x2apic"
438	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
439	help
440	  This enables x2apic support on CPUs that have this feature.
441
442	  This allows 32-bit apic IDs (so it can support very large systems),
443	  and accesses the local apic via MSRs not via mmio.
444
445	  If you don't know what to do here, say N.
446
447config X86_MPPARSE
448	bool "Enable MPS table" if ACPI || SFI
449	default y
450	depends on X86_LOCAL_APIC
451	help
452	  For old smp systems that do not have proper acpi support. Newer systems
453	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
454
455config GOLDFISH
456	def_bool y
457	depends on X86_GOLDFISH
458
459config RETPOLINE
460	bool "Avoid speculative indirect branches in kernel"
461	default y
462	help
463	  Compile kernel with the retpoline compiler options to guard against
464	  kernel-to-user data leaks by avoiding speculative indirect
465	  branches. Requires a compiler with -mindirect-branch=thunk-extern
466	  support for full protection. The kernel may run slower.
467
468config X86_CPU_RESCTRL
469	bool "x86 CPU resource control support"
470	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
471	select KERNFS
472	select PROC_CPU_RESCTRL		if PROC_FS
473	help
474	  Enable x86 CPU resource control support.
475
476	  Provide support for the allocation and monitoring of system resources
477	  usage by the CPU.
478
479	  Intel calls this Intel Resource Director Technology
480	  (Intel(R) RDT). More information about RDT can be found in the
481	  Intel x86 Architecture Software Developer Manual.
482
483	  AMD calls this AMD Platform Quality of Service (AMD QoS).
484	  More information about AMD QoS can be found in the AMD64 Technology
485	  Platform Quality of Service Extensions manual.
486
487	  Say N if unsure.
488
489if X86_32
490config X86_BIGSMP
491	bool "Support for big SMP systems with more than 8 CPUs"
492	depends on SMP
493	help
494	  This option is needed for the systems that have more than 8 CPUs.
495
496config X86_EXTENDED_PLATFORM
497	bool "Support for extended (non-PC) x86 platforms"
498	default y
499	help
500	  If you disable this option then the kernel will only support
501	  standard PC platforms. (which covers the vast majority of
502	  systems out there.)
503
504	  If you enable this option then you'll be able to select support
505	  for the following (non-PC) 32 bit x86 platforms:
506		Goldfish (Android emulator)
507		AMD Elan
508		RDC R-321x SoC
509		SGI 320/540 (Visual Workstation)
510		STA2X11-based (e.g. Northville)
511		Moorestown MID devices
512
513	  If you have one of these systems, or if you want to build a
514	  generic distribution kernel, say Y here - otherwise say N.
515endif
516
517if X86_64
518config X86_EXTENDED_PLATFORM
519	bool "Support for extended (non-PC) x86 platforms"
520	default y
521	help
522	  If you disable this option then the kernel will only support
523	  standard PC platforms. (which covers the vast majority of
524	  systems out there.)
525
526	  If you enable this option then you'll be able to select support
527	  for the following (non-PC) 64 bit x86 platforms:
528		Numascale NumaChip
529		ScaleMP vSMP
530		SGI Ultraviolet
531
532	  If you have one of these systems, or if you want to build a
533	  generic distribution kernel, say Y here - otherwise say N.
534endif
535# This is an alphabetically sorted list of 64 bit extended platforms
536# Please maintain the alphabetic order if and when there are additions
537config X86_NUMACHIP
538	bool "Numascale NumaChip"
539	depends on X86_64
540	depends on X86_EXTENDED_PLATFORM
541	depends on NUMA
542	depends on SMP
543	depends on X86_X2APIC
544	depends on PCI_MMCONFIG
545	help
546	  Adds support for Numascale NumaChip large-SMP systems. Needed to
547	  enable more than ~168 cores.
548	  If you don't have one of these, you should say N here.
549
550config X86_VSMP
551	bool "ScaleMP vSMP"
552	select HYPERVISOR_GUEST
553	select PARAVIRT
554	depends on X86_64 && PCI
555	depends on X86_EXTENDED_PLATFORM
556	depends on SMP
557	help
558	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
559	  supposed to run on these EM64T-based machines.  Only choose this option
560	  if you have one of these machines.
561
562config X86_UV
563	bool "SGI Ultraviolet"
564	depends on X86_64
565	depends on X86_EXTENDED_PLATFORM
566	depends on NUMA
567	depends on EFI
568	depends on X86_X2APIC
569	depends on PCI
570	help
571	  This option is needed in order to support SGI Ultraviolet systems.
572	  If you don't have one of these, you should say N here.
573
574# Following is an alphabetically sorted list of 32 bit extended platforms
575# Please maintain the alphabetic order if and when there are additions
576
577config X86_GOLDFISH
578	bool "Goldfish (Virtual Platform)"
579	depends on X86_EXTENDED_PLATFORM
580	help
581	 Enable support for the Goldfish virtual platform used primarily
582	 for Android development. Unless you are building for the Android
583	 Goldfish emulator say N here.
584
585config X86_INTEL_CE
586	bool "CE4100 TV platform"
587	depends on PCI
588	depends on PCI_GODIRECT
589	depends on X86_IO_APIC
590	depends on X86_32
591	depends on X86_EXTENDED_PLATFORM
592	select X86_REBOOTFIXUPS
593	select OF
594	select OF_EARLY_FLATTREE
595	help
596	  Select for the Intel CE media processor (CE4100) SOC.
597	  This option compiles in support for the CE4100 SOC for settop
598	  boxes and media devices.
599
600config X86_INTEL_MID
601	bool "Intel MID platform support"
602	depends on X86_EXTENDED_PLATFORM
603	depends on X86_PLATFORM_DEVICES
604	depends on PCI
605	depends on X86_64 || (PCI_GOANY && X86_32)
606	depends on X86_IO_APIC
607	select SFI
608	select I2C
609	select DW_APB_TIMER
610	select APB_TIMER
611	select INTEL_SCU_PCI
612	select MFD_INTEL_MSIC
613	help
614	  Select to build a kernel capable of supporting Intel MID (Mobile
615	  Internet Device) platform systems which do not have the PCI legacy
616	  interfaces. If you are building for a PC class system say N here.
617
618	  Intel MID platforms are based on an Intel processor and chipset which
619	  consume less power than most of the x86 derivatives.
620
621config X86_INTEL_QUARK
622	bool "Intel Quark platform support"
623	depends on X86_32
624	depends on X86_EXTENDED_PLATFORM
625	depends on X86_PLATFORM_DEVICES
626	depends on X86_TSC
627	depends on PCI
628	depends on PCI_GOANY
629	depends on X86_IO_APIC
630	select IOSF_MBI
631	select INTEL_IMR
632	select COMMON_CLK
633	help
634	  Select to include support for Quark X1000 SoC.
635	  Say Y here if you have a Quark based system such as the Arduino
636	  compatible Intel Galileo.
637
638config X86_INTEL_LPSS
639	bool "Intel Low Power Subsystem Support"
640	depends on X86 && ACPI && PCI
641	select COMMON_CLK
642	select PINCTRL
643	select IOSF_MBI
644	help
645	  Select to build support for Intel Low Power Subsystem such as
646	  found on Intel Lynxpoint PCH. Selecting this option enables
647	  things like clock tree (common clock framework) and pincontrol
648	  which are needed by the LPSS peripheral drivers.
649
650config X86_AMD_PLATFORM_DEVICE
651	bool "AMD ACPI2Platform devices support"
652	depends on ACPI
653	select COMMON_CLK
654	select PINCTRL
655	help
656	  Select to interpret AMD specific ACPI device to platform device
657	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
658	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
659	  implemented under PINCTRL subsystem.
660
661config IOSF_MBI
662	tristate "Intel SoC IOSF Sideband support for SoC platforms"
663	depends on PCI
664	help
665	  This option enables sideband register access support for Intel SoC
666	  platforms. On these platforms the IOSF sideband is used in lieu of
667	  MSR's for some register accesses, mostly but not limited to thermal
668	  and power. Drivers may query the availability of this device to
669	  determine if they need the sideband in order to work on these
670	  platforms. The sideband is available on the following SoC products.
671	  This list is not meant to be exclusive.
672	   - BayTrail
673	   - Braswell
674	   - Quark
675
676	  You should say Y if you are running a kernel on one of these SoC's.
677
678config IOSF_MBI_DEBUG
679	bool "Enable IOSF sideband access through debugfs"
680	depends on IOSF_MBI && DEBUG_FS
681	help
682	  Select this option to expose the IOSF sideband access registers (MCR,
683	  MDR, MCRX) through debugfs to write and read register information from
684	  different units on the SoC. This is most useful for obtaining device
685	  state information for debug and analysis. As this is a general access
686	  mechanism, users of this option would have specific knowledge of the
687	  device they want to access.
688
689	  If you don't require the option or are in doubt, say N.
690
691config X86_RDC321X
692	bool "RDC R-321x SoC"
693	depends on X86_32
694	depends on X86_EXTENDED_PLATFORM
695	select M486
696	select X86_REBOOTFIXUPS
697	help
698	  This option is needed for RDC R-321x system-on-chip, also known
699	  as R-8610-(G).
700	  If you don't have one of these chips, you should say N here.
701
702config X86_32_NON_STANDARD
703	bool "Support non-standard 32-bit SMP architectures"
704	depends on X86_32 && SMP
705	depends on X86_EXTENDED_PLATFORM
706	help
707	  This option compiles in the bigsmp and STA2X11 default
708	  subarchitectures.  It is intended for a generic binary
709	  kernel. If you select them all, kernel will probe it one by
710	  one and will fallback to default.
711
712# Alphabetically sorted list of Non standard 32 bit platforms
713
714config X86_SUPPORTS_MEMORY_FAILURE
715	def_bool y
716	# MCE code calls memory_failure():
717	depends on X86_MCE
718	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
719	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
720	depends on X86_64 || !SPARSEMEM
721	select ARCH_SUPPORTS_MEMORY_FAILURE
722
723config STA2X11
724	bool "STA2X11 Companion Chip Support"
725	depends on X86_32_NON_STANDARD && PCI
726	select SWIOTLB
727	select MFD_STA2X11
728	select GPIOLIB
729	help
730	  This adds support for boards based on the STA2X11 IO-Hub,
731	  a.k.a. "ConneXt". The chip is used in place of the standard
732	  PC chipset, so all "standard" peripherals are missing. If this
733	  option is selected the kernel will still be able to boot on
734	  standard PC machines.
735
736config X86_32_IRIS
737	tristate "Eurobraille/Iris poweroff module"
738	depends on X86_32
739	help
740	  The Iris machines from EuroBraille do not have APM or ACPI support
741	  to shut themselves down properly.  A special I/O sequence is
742	  needed to do so, which is what this module does at
743	  kernel shutdown.
744
745	  This is only for Iris machines from EuroBraille.
746
747	  If unused, say N.
748
749config SCHED_OMIT_FRAME_POINTER
750	def_bool y
751	prompt "Single-depth WCHAN output"
752	depends on X86
753	help
754	  Calculate simpler /proc/<PID>/wchan values. If this option
755	  is disabled then wchan values will recurse back to the
756	  caller function. This provides more accurate wchan values,
757	  at the expense of slightly more scheduling overhead.
758
759	  If in doubt, say "Y".
760
761menuconfig HYPERVISOR_GUEST
762	bool "Linux guest support"
763	help
764	  Say Y here to enable options for running Linux under various hyper-
765	  visors. This option enables basic hypervisor detection and platform
766	  setup.
767
768	  If you say N, all options in this submenu will be skipped and
769	  disabled, and Linux guest support won't be built in.
770
771if HYPERVISOR_GUEST
772
773config PARAVIRT
774	bool "Enable paravirtualization code"
775	help
776	  This changes the kernel so it can modify itself when it is run
777	  under a hypervisor, potentially improving performance significantly
778	  over full virtualization.  However, when run without a hypervisor
779	  the kernel is theoretically slower and slightly larger.
780
781config PARAVIRT_XXL
782	bool
783
784config PARAVIRT_DEBUG
785	bool "paravirt-ops debugging"
786	depends on PARAVIRT && DEBUG_KERNEL
787	help
788	  Enable to debug paravirt_ops internals.  Specifically, BUG if
789	  a paravirt_op is missing when it is called.
790
791config PARAVIRT_SPINLOCKS
792	bool "Paravirtualization layer for spinlocks"
793	depends on PARAVIRT && SMP
794	help
795	  Paravirtualized spinlocks allow a pvops backend to replace the
796	  spinlock implementation with something virtualization-friendly
797	  (for example, block the virtual CPU rather than spinning).
798
799	  It has a minimal impact on native kernels and gives a nice performance
800	  benefit on paravirtualized KVM / Xen kernels.
801
802	  If you are unsure how to answer this question, answer Y.
803
804config X86_HV_CALLBACK_VECTOR
805	def_bool n
806
807source "arch/x86/xen/Kconfig"
808
809config KVM_GUEST
810	bool "KVM Guest support (including kvmclock)"
811	depends on PARAVIRT
812	select PARAVIRT_CLOCK
813	select ARCH_CPUIDLE_HALTPOLL
814	select X86_HV_CALLBACK_VECTOR
815	default y
816	help
817	  This option enables various optimizations for running under the KVM
818	  hypervisor. It includes a paravirtualized clock, so that instead
819	  of relying on a PIT (or probably other) emulation by the
820	  underlying device model, the host provides the guest with
821	  timing infrastructure such as time of day, and system time
822
823config ARCH_CPUIDLE_HALTPOLL
824	def_bool n
825	prompt "Disable host haltpoll when loading haltpoll driver"
826	help
827	  If virtualized under KVM, disable host haltpoll.
828
829config PVH
830	bool "Support for running PVH guests"
831	help
832	  This option enables the PVH entry point for guest virtual machines
833	  as specified in the x86/HVM direct boot ABI.
834
835config PARAVIRT_TIME_ACCOUNTING
836	bool "Paravirtual steal time accounting"
837	depends on PARAVIRT
838	help
839	  Select this option to enable fine granularity task steal time
840	  accounting. Time spent executing other tasks in parallel with
841	  the current vCPU is discounted from the vCPU power. To account for
842	  that, there can be a small performance impact.
843
844	  If in doubt, say N here.
845
846config PARAVIRT_CLOCK
847	bool
848
849config JAILHOUSE_GUEST
850	bool "Jailhouse non-root cell support"
851	depends on X86_64 && PCI
852	select X86_PM_TIMER
853	help
854	  This option allows to run Linux as guest in a Jailhouse non-root
855	  cell. You can leave this option disabled if you only want to start
856	  Jailhouse and run Linux afterwards in the root cell.
857
858config ACRN_GUEST
859	bool "ACRN Guest support"
860	depends on X86_64
861	select X86_HV_CALLBACK_VECTOR
862	help
863	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
864	  a flexible, lightweight reference open-source hypervisor, built with
865	  real-time and safety-criticality in mind. It is built for embedded
866	  IOT with small footprint and real-time features. More details can be
867	  found in https://projectacrn.org/.
868
869endif #HYPERVISOR_GUEST
870
871source "arch/x86/Kconfig.cpu"
872
873config HPET_TIMER
874	def_bool X86_64
875	prompt "HPET Timer Support" if X86_32
876	help
877	  Use the IA-PC HPET (High Precision Event Timer) to manage
878	  time in preference to the PIT and RTC, if a HPET is
879	  present.
880	  HPET is the next generation timer replacing legacy 8254s.
881	  The HPET provides a stable time base on SMP
882	  systems, unlike the TSC, but it is more expensive to access,
883	  as it is off-chip.  The interface used is documented
884	  in the HPET spec, revision 1.
885
886	  You can safely choose Y here.  However, HPET will only be
887	  activated if the platform and the BIOS support this feature.
888	  Otherwise the 8254 will be used for timing services.
889
890	  Choose N to continue using the legacy 8254 timer.
891
892config HPET_EMULATE_RTC
893	def_bool y
894	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
895
896config APB_TIMER
897	def_bool y if X86_INTEL_MID
898	prompt "Intel MID APB Timer Support" if X86_INTEL_MID
899	select DW_APB_TIMER
900	depends on X86_INTEL_MID && SFI
901	help
902	 APB timer is the replacement for 8254, HPET on X86 MID platforms.
903	 The APBT provides a stable time base on SMP
904	 systems, unlike the TSC, but it is more expensive to access,
905	 as it is off-chip. APB timers are always running regardless of CPU
906	 C states, they are used as per CPU clockevent device when possible.
907
908# Mark as expert because too many people got it wrong.
909# The code disables itself when not needed.
910config DMI
911	default y
912	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
913	bool "Enable DMI scanning" if EXPERT
914	help
915	  Enabled scanning of DMI to identify machine quirks. Say Y
916	  here unless you have verified that your setup is not
917	  affected by entries in the DMI blacklist. Required by PNP
918	  BIOS code.
919
920config GART_IOMMU
921	bool "Old AMD GART IOMMU support"
922	select DMA_OPS
923	select IOMMU_HELPER
924	select SWIOTLB
925	depends on X86_64 && PCI && AMD_NB
926	help
927	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
928	  GART based hardware IOMMUs.
929
930	  The GART supports full DMA access for devices with 32-bit access
931	  limitations, on systems with more than 3 GB. This is usually needed
932	  for USB, sound, many IDE/SATA chipsets and some other devices.
933
934	  Newer systems typically have a modern AMD IOMMU, supported via
935	  the CONFIG_AMD_IOMMU=y config option.
936
937	  In normal configurations this driver is only active when needed:
938	  there's more than 3 GB of memory and the system contains a
939	  32-bit limited device.
940
941	  If unsure, say Y.
942
943config MAXSMP
944	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
945	depends on X86_64 && SMP && DEBUG_KERNEL
946	select CPUMASK_OFFSTACK
947	help
948	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
949	  If unsure, say N.
950
951#
952# The maximum number of CPUs supported:
953#
954# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
955# and which can be configured interactively in the
956# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
957#
958# The ranges are different on 32-bit and 64-bit kernels, depending on
959# hardware capabilities and scalability features of the kernel.
960#
961# ( If MAXSMP is enabled we just use the highest possible value and disable
962#   interactive configuration. )
963#
964
965config NR_CPUS_RANGE_BEGIN
966	int
967	default NR_CPUS_RANGE_END if MAXSMP
968	default    1 if !SMP
969	default    2
970
971config NR_CPUS_RANGE_END
972	int
973	depends on X86_32
974	default   64 if  SMP &&  X86_BIGSMP
975	default    8 if  SMP && !X86_BIGSMP
976	default    1 if !SMP
977
978config NR_CPUS_RANGE_END
979	int
980	depends on X86_64
981	default 8192 if  SMP && CPUMASK_OFFSTACK
982	default  512 if  SMP && !CPUMASK_OFFSTACK
983	default    1 if !SMP
984
985config NR_CPUS_DEFAULT
986	int
987	depends on X86_32
988	default   32 if  X86_BIGSMP
989	default    8 if  SMP
990	default    1 if !SMP
991
992config NR_CPUS_DEFAULT
993	int
994	depends on X86_64
995	default 8192 if  MAXSMP
996	default   64 if  SMP
997	default    1 if !SMP
998
999config NR_CPUS
1000	int "Maximum number of CPUs" if SMP && !MAXSMP
1001	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1002	default NR_CPUS_DEFAULT
1003	help
1004	  This allows you to specify the maximum number of CPUs which this
1005	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1006	  supported value is 8192, otherwise the maximum value is 512.  The
1007	  minimum value which makes sense is 2.
1008
1009	  This is purely to save memory: each supported CPU adds about 8KB
1010	  to the kernel image.
1011
1012config SCHED_SMT
1013	def_bool y if SMP
1014
1015config SCHED_MC
1016	def_bool y
1017	prompt "Multi-core scheduler support"
1018	depends on SMP
1019	help
1020	  Multi-core scheduler support improves the CPU scheduler's decision
1021	  making when dealing with multi-core CPU chips at a cost of slightly
1022	  increased overhead in some places. If unsure say N here.
1023
1024config SCHED_MC_PRIO
1025	bool "CPU core priorities scheduler support"
1026	depends on SCHED_MC && CPU_SUP_INTEL
1027	select X86_INTEL_PSTATE
1028	select CPU_FREQ
1029	default y
1030	help
1031	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1032	  core ordering determined at manufacturing time, which allows
1033	  certain cores to reach higher turbo frequencies (when running
1034	  single threaded workloads) than others.
1035
1036	  Enabling this kernel feature teaches the scheduler about
1037	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1038	  scheduler's CPU selection logic accordingly, so that higher
1039	  overall system performance can be achieved.
1040
1041	  This feature will have no effect on CPUs without this feature.
1042
1043	  If unsure say Y here.
1044
1045config UP_LATE_INIT
1046	def_bool y
1047	depends on !SMP && X86_LOCAL_APIC
1048
1049config X86_UP_APIC
1050	bool "Local APIC support on uniprocessors" if !PCI_MSI
1051	default PCI_MSI
1052	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1053	help
1054	  A local APIC (Advanced Programmable Interrupt Controller) is an
1055	  integrated interrupt controller in the CPU. If you have a single-CPU
1056	  system which has a processor with a local APIC, you can say Y here to
1057	  enable and use it. If you say Y here even though your machine doesn't
1058	  have a local APIC, then the kernel will still run with no slowdown at
1059	  all. The local APIC supports CPU-generated self-interrupts (timer,
1060	  performance counters), and the NMI watchdog which detects hard
1061	  lockups.
1062
1063config X86_UP_IOAPIC
1064	bool "IO-APIC support on uniprocessors"
1065	depends on X86_UP_APIC
1066	help
1067	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1068	  SMP-capable replacement for PC-style interrupt controllers. Most
1069	  SMP systems and many recent uniprocessor systems have one.
1070
1071	  If you have a single-CPU system with an IO-APIC, you can say Y here
1072	  to use it. If you say Y here even though your machine doesn't have
1073	  an IO-APIC, then the kernel will still run with no slowdown at all.
1074
1075config X86_LOCAL_APIC
1076	def_bool y
1077	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1078	select IRQ_DOMAIN_HIERARCHY
1079	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1080
1081config X86_IO_APIC
1082	def_bool y
1083	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1084
1085config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1086	bool "Reroute for broken boot IRQs"
1087	depends on X86_IO_APIC
1088	help
1089	  This option enables a workaround that fixes a source of
1090	  spurious interrupts. This is recommended when threaded
1091	  interrupt handling is used on systems where the generation of
1092	  superfluous "boot interrupts" cannot be disabled.
1093
1094	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1095	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1096	  kernel does during interrupt handling). On chipsets where this
1097	  boot IRQ generation cannot be disabled, this workaround keeps
1098	  the original IRQ line masked so that only the equivalent "boot
1099	  IRQ" is delivered to the CPUs. The workaround also tells the
1100	  kernel to set up the IRQ handler on the boot IRQ line. In this
1101	  way only one interrupt is delivered to the kernel. Otherwise
1102	  the spurious second interrupt may cause the kernel to bring
1103	  down (vital) interrupt lines.
1104
1105	  Only affects "broken" chipsets. Interrupt sharing may be
1106	  increased on these systems.
1107
1108config X86_MCE
1109	bool "Machine Check / overheating reporting"
1110	select GENERIC_ALLOCATOR
1111	default y
1112	help
1113	  Machine Check support allows the processor to notify the
1114	  kernel if it detects a problem (e.g. overheating, data corruption).
1115	  The action the kernel takes depends on the severity of the problem,
1116	  ranging from warning messages to halting the machine.
1117
1118config X86_MCELOG_LEGACY
1119	bool "Support for deprecated /dev/mcelog character device"
1120	depends on X86_MCE
1121	help
1122	  Enable support for /dev/mcelog which is needed by the old mcelog
1123	  userspace logging daemon. Consider switching to the new generation
1124	  rasdaemon solution.
1125
1126config X86_MCE_INTEL
1127	def_bool y
1128	prompt "Intel MCE features"
1129	depends on X86_MCE && X86_LOCAL_APIC
1130	help
1131	   Additional support for intel specific MCE features such as
1132	   the thermal monitor.
1133
1134config X86_MCE_AMD
1135	def_bool y
1136	prompt "AMD MCE features"
1137	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1138	help
1139	   Additional support for AMD specific MCE features such as
1140	   the DRAM Error Threshold.
1141
1142config X86_ANCIENT_MCE
1143	bool "Support for old Pentium 5 / WinChip machine checks"
1144	depends on X86_32 && X86_MCE
1145	help
1146	  Include support for machine check handling on old Pentium 5 or WinChip
1147	  systems. These typically need to be enabled explicitly on the command
1148	  line.
1149
1150config X86_MCE_THRESHOLD
1151	depends on X86_MCE_AMD || X86_MCE_INTEL
1152	def_bool y
1153
1154config X86_MCE_INJECT
1155	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1156	tristate "Machine check injector support"
1157	help
1158	  Provide support for injecting machine checks for testing purposes.
1159	  If you don't know what a machine check is and you don't do kernel
1160	  QA it is safe to say n.
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	help
1303	  If you say Y here, you will be able to update the microcode on
1304	  Intel and AMD processors. The Intel support is for the IA32 family,
1305	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1306	  AMD support is for families 0x10 and later. You will obviously need
1307	  the actual microcode binary data itself which is not shipped with
1308	  the Linux kernel.
1309
1310	  The preferred method to load microcode from a detached initrd is described
1311	  in Documentation/x86/microcode.rst. For that you need to enable
1312	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1313	  initrd for microcode blobs.
1314
1315	  In addition, you can build the microcode into the kernel. For that you
1316	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1317	  config option.
1318
1319config MICROCODE_INTEL
1320	bool "Intel microcode loading support"
1321	depends on MICROCODE
1322	default MICROCODE
1323	help
1324	  This options enables microcode patch loading support for Intel
1325	  processors.
1326
1327	  For the current Intel microcode data package go to
1328	  <https://downloadcenter.intel.com> and search for
1329	  'Linux Processor Microcode Data File'.
1330
1331config MICROCODE_AMD
1332	bool "AMD microcode loading support"
1333	depends on MICROCODE
1334	help
1335	  If you select this option, microcode patch loading support for AMD
1336	  processors will be enabled.
1337
1338config MICROCODE_OLD_INTERFACE
1339	bool "Ancient loading interface (DEPRECATED)"
1340	default n
1341	depends on MICROCODE
1342	help
1343	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1344	  which was used by userspace tools like iucode_tool and microcode.ctl.
1345	  It is inadequate because it runs too late to be able to properly
1346	  load microcode on a machine and it needs special tools. Instead, you
1347	  should've switched to the early loading method with the initrd or
1348	  builtin microcode by now: Documentation/x86/microcode.rst
1349
1350config X86_MSR
1351	tristate "/dev/cpu/*/msr - Model-specific register support"
1352	help
1353	  This device gives privileged processes access to the x86
1354	  Model-Specific Registers (MSRs).  It is a character device with
1355	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1356	  MSR accesses are directed to a specific CPU on multi-processor
1357	  systems.
1358
1359config X86_CPUID
1360	tristate "/dev/cpu/*/cpuid - CPU information support"
1361	help
1362	  This device gives processes access to the x86 CPUID instruction to
1363	  be executed on a specific processor.  It is a character device
1364	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1365	  /dev/cpu/31/cpuid.
1366
1367choice
1368	prompt "High Memory Support"
1369	default HIGHMEM4G
1370	depends on X86_32
1371
1372config NOHIGHMEM
1373	bool "off"
1374	help
1375	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1376	  However, the address space of 32-bit x86 processors is only 4
1377	  Gigabytes large. That means that, if you have a large amount of
1378	  physical memory, not all of it can be "permanently mapped" by the
1379	  kernel. The physical memory that's not permanently mapped is called
1380	  "high memory".
1381
1382	  If you are compiling a kernel which will never run on a machine with
1383	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1384	  choice and suitable for most users). This will result in a "3GB/1GB"
1385	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1386	  space and the remaining part of the 4GB virtual memory space is used
1387	  by the kernel to permanently map as much physical memory as
1388	  possible.
1389
1390	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1391	  answer "4GB" here.
1392
1393	  If more than 4 Gigabytes is used then answer "64GB" here. This
1394	  selection turns Intel PAE (Physical Address Extension) mode on.
1395	  PAE implements 3-level paging on IA32 processors. PAE is fully
1396	  supported by Linux, PAE mode is implemented on all recent Intel
1397	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1398	  then the kernel will not boot on CPUs that don't support PAE!
1399
1400	  The actual amount of total physical memory will either be
1401	  auto detected or can be forced by using a kernel command line option
1402	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1403	  your boot loader (lilo or loadlin) about how to pass options to the
1404	  kernel at boot time.)
1405
1406	  If unsure, say "off".
1407
1408config HIGHMEM4G
1409	bool "4GB"
1410	help
1411	  Select this if you have a 32-bit processor and between 1 and 4
1412	  gigabytes of physical RAM.
1413
1414config HIGHMEM64G
1415	bool "64GB"
1416	depends on !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1417	select X86_PAE
1418	help
1419	  Select this if you have a 32-bit processor and more than 4
1420	  gigabytes of physical RAM.
1421
1422endchoice
1423
1424choice
1425	prompt "Memory split" if EXPERT
1426	default VMSPLIT_3G
1427	depends on X86_32
1428	help
1429	  Select the desired split between kernel and user memory.
1430
1431	  If the address range available to the kernel is less than the
1432	  physical memory installed, the remaining memory will be available
1433	  as "high memory". Accessing high memory is a little more costly
1434	  than low memory, as it needs to be mapped into the kernel first.
1435	  Note that increasing the kernel address space limits the range
1436	  available to user programs, making the address space there
1437	  tighter.  Selecting anything other than the default 3G/1G split
1438	  will also likely make your kernel incompatible with binary-only
1439	  kernel modules.
1440
1441	  If you are not absolutely sure what you are doing, leave this
1442	  option alone!
1443
1444	config VMSPLIT_3G
1445		bool "3G/1G user/kernel split"
1446	config VMSPLIT_3G_OPT
1447		depends on !X86_PAE
1448		bool "3G/1G user/kernel split (for full 1G low memory)"
1449	config VMSPLIT_2G
1450		bool "2G/2G user/kernel split"
1451	config VMSPLIT_2G_OPT
1452		depends on !X86_PAE
1453		bool "2G/2G user/kernel split (for full 2G low memory)"
1454	config VMSPLIT_1G
1455		bool "1G/3G user/kernel split"
1456endchoice
1457
1458config PAGE_OFFSET
1459	hex
1460	default 0xB0000000 if VMSPLIT_3G_OPT
1461	default 0x80000000 if VMSPLIT_2G
1462	default 0x78000000 if VMSPLIT_2G_OPT
1463	default 0x40000000 if VMSPLIT_1G
1464	default 0xC0000000
1465	depends on X86_32
1466
1467config HIGHMEM
1468	def_bool y
1469	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1470
1471config X86_PAE
1472	bool "PAE (Physical Address Extension) Support"
1473	depends on X86_32 && !HIGHMEM4G
1474	select PHYS_ADDR_T_64BIT
1475	select SWIOTLB
1476	help
1477	  PAE is required for NX support, and furthermore enables
1478	  larger swapspace support for non-overcommit purposes. It
1479	  has the cost of more pagetable lookup overhead, and also
1480	  consumes more pagetable space per process.
1481
1482config X86_5LEVEL
1483	bool "Enable 5-level page tables support"
1484	default y
1485	select DYNAMIC_MEMORY_LAYOUT
1486	select SPARSEMEM_VMEMMAP
1487	depends on X86_64
1488	help
1489	  5-level paging enables access to larger address space:
1490	  upto 128 PiB of virtual address space and 4 PiB of
1491	  physical address space.
1492
1493	  It will be supported by future Intel CPUs.
1494
1495	  A kernel with the option enabled can be booted on machines that
1496	  support 4- or 5-level paging.
1497
1498	  See Documentation/x86/x86_64/5level-paging.rst for more
1499	  information.
1500
1501	  Say N if unsure.
1502
1503config X86_DIRECT_GBPAGES
1504	def_bool y
1505	depends on X86_64
1506	help
1507	  Certain kernel features effectively disable kernel
1508	  linear 1 GB mappings (even if the CPU otherwise
1509	  supports them), so don't confuse the user by printing
1510	  that we have them enabled.
1511
1512config X86_CPA_STATISTICS
1513	bool "Enable statistic for Change Page Attribute"
1514	depends on DEBUG_FS
1515	help
1516	  Expose statistics about the Change Page Attribute mechanism, which
1517	  helps to determine the effectiveness of preserving large and huge
1518	  page mappings when mapping protections are changed.
1519
1520config AMD_MEM_ENCRYPT
1521	bool "AMD Secure Memory Encryption (SME) support"
1522	depends on X86_64 && CPU_SUP_AMD
1523	select DMA_COHERENT_POOL
1524	select DYNAMIC_PHYSICAL_MASK
1525	select ARCH_USE_MEMREMAP_PROT
1526	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1527	select INSTRUCTION_DECODER
1528	help
1529	  Say yes to enable support for the encryption of system memory.
1530	  This requires an AMD processor that supports Secure Memory
1531	  Encryption (SME).
1532
1533config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1534	bool "Activate AMD Secure Memory Encryption (SME) by default"
1535	default y
1536	depends on AMD_MEM_ENCRYPT
1537	help
1538	  Say yes to have system memory encrypted by default if running on
1539	  an AMD processor that supports Secure Memory Encryption (SME).
1540
1541	  If set to Y, then the encryption of system memory can be
1542	  deactivated with the mem_encrypt=off command line option.
1543
1544	  If set to N, then the encryption of system memory can be
1545	  activated with the mem_encrypt=on command line option.
1546
1547# Common NUMA Features
1548config NUMA
1549	bool "NUMA Memory Allocation and Scheduler Support"
1550	depends on SMP
1551	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1552	default y if X86_BIGSMP
1553	help
1554	  Enable NUMA (Non-Uniform Memory Access) support.
1555
1556	  The kernel will try to allocate memory used by a CPU on the
1557	  local memory controller of the CPU and add some more
1558	  NUMA awareness to the kernel.
1559
1560	  For 64-bit this is recommended if the system is Intel Core i7
1561	  (or later), AMD Opteron, or EM64T NUMA.
1562
1563	  For 32-bit this is only needed if you boot a 32-bit
1564	  kernel on a 64-bit NUMA platform.
1565
1566	  Otherwise, you should say N.
1567
1568config AMD_NUMA
1569	def_bool y
1570	prompt "Old style AMD Opteron NUMA detection"
1571	depends on X86_64 && NUMA && PCI
1572	help
1573	  Enable AMD NUMA node topology detection.  You should say Y here if
1574	  you have a multi processor AMD system. This uses an old method to
1575	  read the NUMA configuration directly from the builtin Northbridge
1576	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1577	  which also takes priority if both are compiled in.
1578
1579config X86_64_ACPI_NUMA
1580	def_bool y
1581	prompt "ACPI NUMA detection"
1582	depends on X86_64 && NUMA && ACPI && PCI
1583	select ACPI_NUMA
1584	help
1585	  Enable ACPI SRAT based node topology detection.
1586
1587config NUMA_EMU
1588	bool "NUMA emulation"
1589	depends on NUMA
1590	help
1591	  Enable NUMA emulation. A flat machine will be split
1592	  into virtual nodes when booted with "numa=fake=N", where N is the
1593	  number of nodes. This is only useful for debugging.
1594
1595config NODES_SHIFT
1596	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1597	range 1 10
1598	default "10" if MAXSMP
1599	default "6" if X86_64
1600	default "3"
1601	depends on NEED_MULTIPLE_NODES
1602	help
1603	  Specify the maximum number of NUMA Nodes available on the target
1604	  system.  Increases memory reserved to accommodate various tables.
1605
1606config ARCH_FLATMEM_ENABLE
1607	def_bool y
1608	depends on X86_32 && !NUMA
1609
1610config ARCH_SPARSEMEM_ENABLE
1611	def_bool y
1612	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1613	select SPARSEMEM_STATIC if X86_32
1614	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1615
1616config ARCH_SPARSEMEM_DEFAULT
1617	def_bool X86_64 || (NUMA && X86_32)
1618
1619config ARCH_SELECT_MEMORY_MODEL
1620	def_bool y
1621	depends on ARCH_SPARSEMEM_ENABLE
1622
1623config ARCH_MEMORY_PROBE
1624	bool "Enable sysfs memory/probe interface"
1625	depends on X86_64 && MEMORY_HOTPLUG
1626	help
1627	  This option enables a sysfs memory/probe interface for testing.
1628	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1629	  If you are unsure how to answer this question, answer N.
1630
1631config ARCH_PROC_KCORE_TEXT
1632	def_bool y
1633	depends on X86_64 && PROC_KCORE
1634
1635config ILLEGAL_POINTER_VALUE
1636	hex
1637	default 0 if X86_32
1638	default 0xdead000000000000 if X86_64
1639
1640config X86_PMEM_LEGACY_DEVICE
1641	bool
1642
1643config X86_PMEM_LEGACY
1644	tristate "Support non-standard NVDIMMs and ADR protected memory"
1645	depends on PHYS_ADDR_T_64BIT
1646	depends on BLK_DEV
1647	select X86_PMEM_LEGACY_DEVICE
1648	select NUMA_KEEP_MEMINFO if NUMA
1649	select LIBNVDIMM
1650	help
1651	  Treat memory marked using the non-standard e820 type of 12 as used
1652	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1653	  The kernel will offer these regions to the 'pmem' driver so
1654	  they can be used for persistent storage.
1655
1656	  Say Y if unsure.
1657
1658config HIGHPTE
1659	bool "Allocate 3rd-level pagetables from highmem"
1660	depends on HIGHMEM
1661	help
1662	  The VM uses one page table entry for each page of physical memory.
1663	  For systems with a lot of RAM, this can be wasteful of precious
1664	  low memory.  Setting this option will put user-space page table
1665	  entries in high memory.
1666
1667config X86_CHECK_BIOS_CORRUPTION
1668	bool "Check for low memory corruption"
1669	help
1670	  Periodically check for memory corruption in low memory, which
1671	  is suspected to be caused by BIOS.  Even when enabled in the
1672	  configuration, it is disabled at runtime.  Enable it by
1673	  setting "memory_corruption_check=1" on the kernel command
1674	  line.  By default it scans the low 64k of memory every 60
1675	  seconds; see the memory_corruption_check_size and
1676	  memory_corruption_check_period parameters in
1677	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1678
1679	  When enabled with the default parameters, this option has
1680	  almost no overhead, as it reserves a relatively small amount
1681	  of memory and scans it infrequently.  It both detects corruption
1682	  and prevents it from affecting the running system.
1683
1684	  It is, however, intended as a diagnostic tool; if repeatable
1685	  BIOS-originated corruption always affects the same memory,
1686	  you can use memmap= to prevent the kernel from using that
1687	  memory.
1688
1689config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1690	bool "Set the default setting of memory_corruption_check"
1691	depends on X86_CHECK_BIOS_CORRUPTION
1692	default y
1693	help
1694	  Set whether the default state of memory_corruption_check is
1695	  on or off.
1696
1697config X86_RESERVE_LOW
1698	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1699	default 64
1700	range 4 640
1701	help
1702	  Specify the amount of low memory to reserve for the BIOS.
1703
1704	  The first page contains BIOS data structures that the kernel
1705	  must not use, so that page must always be reserved.
1706
1707	  By default we reserve the first 64K of physical RAM, as a
1708	  number of BIOSes are known to corrupt that memory range
1709	  during events such as suspend/resume or monitor cable
1710	  insertion, so it must not be used by the kernel.
1711
1712	  You can set this to 4 if you are absolutely sure that you
1713	  trust the BIOS to get all its memory reservations and usages
1714	  right.  If you know your BIOS have problems beyond the
1715	  default 64K area, you can set this to 640 to avoid using the
1716	  entire low memory range.
1717
1718	  If you have doubts about the BIOS (e.g. suspend/resume does
1719	  not work or there's kernel crashes after certain hardware
1720	  hotplug events) then you might want to enable
1721	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1722	  typical corruption patterns.
1723
1724	  Leave this to the default value of 64 if you are unsure.
1725
1726config MATH_EMULATION
1727	bool
1728	depends on MODIFY_LDT_SYSCALL
1729	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1730	help
1731	  Linux can emulate a math coprocessor (used for floating point
1732	  operations) if you don't have one. 486DX and Pentium processors have
1733	  a math coprocessor built in, 486SX and 386 do not, unless you added
1734	  a 487DX or 387, respectively. (The messages during boot time can
1735	  give you some hints here ["man dmesg"].) Everyone needs either a
1736	  coprocessor or this emulation.
1737
1738	  If you don't have a math coprocessor, you need to say Y here; if you
1739	  say Y here even though you have a coprocessor, the coprocessor will
1740	  be used nevertheless. (This behavior can be changed with the kernel
1741	  command line option "no387", which comes handy if your coprocessor
1742	  is broken. Try "man bootparam" or see the documentation of your boot
1743	  loader (lilo or loadlin) about how to pass options to the kernel at
1744	  boot time.) This means that it is a good idea to say Y here if you
1745	  intend to use this kernel on different machines.
1746
1747	  More information about the internals of the Linux math coprocessor
1748	  emulation can be found in <file:arch/x86/math-emu/README>.
1749
1750	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1751	  kernel, it won't hurt.
1752
1753config MTRR
1754	def_bool y
1755	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1756	help
1757	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1758	  the Memory Type Range Registers (MTRRs) may be used to control
1759	  processor access to memory ranges. This is most useful if you have
1760	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1761	  allows bus write transfers to be combined into a larger transfer
1762	  before bursting over the PCI/AGP bus. This can increase performance
1763	  of image write operations 2.5 times or more. Saying Y here creates a
1764	  /proc/mtrr file which may be used to manipulate your processor's
1765	  MTRRs. Typically the X server should use this.
1766
1767	  This code has a reasonably generic interface so that similar
1768	  control registers on other processors can be easily supported
1769	  as well:
1770
1771	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1772	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1773	  these, the ARRs are used to emulate the MTRRs.
1774	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1775	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1776	  write-combining. All of these processors are supported by this code
1777	  and it makes sense to say Y here if you have one of them.
1778
1779	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1780	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1781	  can lead to all sorts of problems, so it's good to say Y here.
1782
1783	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1784	  just add about 9 KB to your kernel.
1785
1786	  See <file:Documentation/x86/mtrr.rst> for more information.
1787
1788config MTRR_SANITIZER
1789	def_bool y
1790	prompt "MTRR cleanup support"
1791	depends on MTRR
1792	help
1793	  Convert MTRR layout from continuous to discrete, so X drivers can
1794	  add writeback entries.
1795
1796	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1797	  The largest mtrr entry size for a continuous block can be set with
1798	  mtrr_chunk_size.
1799
1800	  If unsure, say Y.
1801
1802config MTRR_SANITIZER_ENABLE_DEFAULT
1803	int "MTRR cleanup enable value (0-1)"
1804	range 0 1
1805	default "0"
1806	depends on MTRR_SANITIZER
1807	help
1808	  Enable mtrr cleanup default value
1809
1810config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1811	int "MTRR cleanup spare reg num (0-7)"
1812	range 0 7
1813	default "1"
1814	depends on MTRR_SANITIZER
1815	help
1816	  mtrr cleanup spare entries default, it can be changed via
1817	  mtrr_spare_reg_nr=N on the kernel command line.
1818
1819config X86_PAT
1820	def_bool y
1821	prompt "x86 PAT support" if EXPERT
1822	depends on MTRR
1823	help
1824	  Use PAT attributes to setup page level cache control.
1825
1826	  PATs are the modern equivalents of MTRRs and are much more
1827	  flexible than MTRRs.
1828
1829	  Say N here if you see bootup problems (boot crash, boot hang,
1830	  spontaneous reboots) or a non-working video driver.
1831
1832	  If unsure, say Y.
1833
1834config ARCH_USES_PG_UNCACHED
1835	def_bool y
1836	depends on X86_PAT
1837
1838config ARCH_RANDOM
1839	def_bool y
1840	prompt "x86 architectural random number generator" if EXPERT
1841	help
1842	  Enable the x86 architectural RDRAND instruction
1843	  (Intel Bull Mountain technology) to generate random numbers.
1844	  If supported, this is a high bandwidth, cryptographically
1845	  secure hardware random number generator.
1846
1847config X86_SMAP
1848	def_bool y
1849	prompt "Supervisor Mode Access Prevention" if EXPERT
1850	help
1851	  Supervisor Mode Access Prevention (SMAP) is a security
1852	  feature in newer Intel processors.  There is a small
1853	  performance cost if this enabled and turned on; there is
1854	  also a small increase in the kernel size if this is enabled.
1855
1856	  If unsure, say Y.
1857
1858config X86_UMIP
1859	def_bool y
1860	prompt "User Mode Instruction Prevention" if EXPERT
1861	help
1862	  User Mode Instruction Prevention (UMIP) is a security feature in
1863	  some x86 processors. If enabled, a general protection fault is
1864	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1865	  executed in user mode. These instructions unnecessarily expose
1866	  information about the hardware state.
1867
1868	  The vast majority of applications do not use these instructions.
1869	  For the very few that do, software emulation is provided in
1870	  specific cases in protected and virtual-8086 modes. Emulated
1871	  results are dummy.
1872
1873config X86_INTEL_MEMORY_PROTECTION_KEYS
1874	prompt "Memory Protection Keys"
1875	def_bool y
1876	# Note: only available in 64-bit mode
1877	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1878	select ARCH_USES_HIGH_VMA_FLAGS
1879	select ARCH_HAS_PKEYS
1880	help
1881	  Memory Protection Keys provides a mechanism for enforcing
1882	  page-based protections, but without requiring modification of the
1883	  page tables when an application changes protection domains.
1884
1885	  For details, see Documentation/core-api/protection-keys.rst
1886
1887	  If unsure, say y.
1888
1889choice
1890	prompt "TSX enable mode"
1891	depends on CPU_SUP_INTEL
1892	default X86_INTEL_TSX_MODE_OFF
1893	help
1894	  Intel's TSX (Transactional Synchronization Extensions) feature
1895	  allows to optimize locking protocols through lock elision which
1896	  can lead to a noticeable performance boost.
1897
1898	  On the other hand it has been shown that TSX can be exploited
1899	  to form side channel attacks (e.g. TAA) and chances are there
1900	  will be more of those attacks discovered in the future.
1901
1902	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1903	  might override this decision by tsx=on the command line parameter.
1904	  Even with TSX enabled, the kernel will attempt to enable the best
1905	  possible TAA mitigation setting depending on the microcode available
1906	  for the particular machine.
1907
1908	  This option allows to set the default tsx mode between tsx=on, =off
1909	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1910	  details.
1911
1912	  Say off if not sure, auto if TSX is in use but it should be used on safe
1913	  platforms or on if TSX is in use and the security aspect of tsx is not
1914	  relevant.
1915
1916config X86_INTEL_TSX_MODE_OFF
1917	bool "off"
1918	help
1919	  TSX is disabled if possible - equals to tsx=off command line parameter.
1920
1921config X86_INTEL_TSX_MODE_ON
1922	bool "on"
1923	help
1924	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1925	  line parameter.
1926
1927config X86_INTEL_TSX_MODE_AUTO
1928	bool "auto"
1929	help
1930	  TSX is enabled on TSX capable HW that is believed to be safe against
1931	  side channel attacks- equals the tsx=auto command line parameter.
1932endchoice
1933
1934config X86_SGX
1935	bool "Software Guard eXtensions (SGX)"
1936	depends on X86_64 && CPU_SUP_INTEL
1937	depends on CRYPTO=y
1938	depends on CRYPTO_SHA256=y
1939	select SRCU
1940	select MMU_NOTIFIER
1941	help
1942	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1943	  that can be used by applications to set aside private regions of code
1944	  and data, referred to as enclaves. An enclave's private memory can
1945	  only be accessed by code running within the enclave. Accesses from
1946	  outside the enclave, including other enclaves, are disallowed by
1947	  hardware.
1948
1949	  If unsure, say N.
1950
1951config EFI
1952	bool "EFI runtime service support"
1953	depends on ACPI
1954	select UCS2_STRING
1955	select EFI_RUNTIME_WRAPPERS
1956	help
1957	  This enables the kernel to use EFI runtime services that are
1958	  available (such as the EFI variable services).
1959
1960	  This option is only useful on systems that have EFI firmware.
1961	  In addition, you should use the latest ELILO loader available
1962	  at <http://elilo.sourceforge.net> in order to take advantage
1963	  of EFI runtime services. However, even with this option, the
1964	  resultant kernel should continue to boot on existing non-EFI
1965	  platforms.
1966
1967config EFI_STUB
1968	bool "EFI stub support"
1969	depends on EFI && !X86_USE_3DNOW
1970	depends on $(cc-option,-mabi=ms) || X86_32
1971	select RELOCATABLE
1972	help
1973	  This kernel feature allows a bzImage to be loaded directly
1974	  by EFI firmware without the use of a bootloader.
1975
1976	  See Documentation/admin-guide/efi-stub.rst for more information.
1977
1978config EFI_MIXED
1979	bool "EFI mixed-mode support"
1980	depends on EFI_STUB && X86_64
1981	help
1982	   Enabling this feature allows a 64-bit kernel to be booted
1983	   on a 32-bit firmware, provided that your CPU supports 64-bit
1984	   mode.
1985
1986	   Note that it is not possible to boot a mixed-mode enabled
1987	   kernel via the EFI boot stub - a bootloader that supports
1988	   the EFI handover protocol must be used.
1989
1990	   If unsure, say N.
1991
1992source "kernel/Kconfig.hz"
1993
1994config KEXEC
1995	bool "kexec system call"
1996	select KEXEC_CORE
1997	help
1998	  kexec is a system call that implements the ability to shutdown your
1999	  current kernel, and to start another kernel.  It is like a reboot
2000	  but it is independent of the system firmware.   And like a reboot
2001	  you can start any kernel with it, not just Linux.
2002
2003	  The name comes from the similarity to the exec system call.
2004
2005	  It is an ongoing process to be certain the hardware in a machine
2006	  is properly shutdown, so do not be surprised if this code does not
2007	  initially work for you.  As of this writing the exact hardware
2008	  interface is strongly in flux, so no good recommendation can be
2009	  made.
2010
2011config KEXEC_FILE
2012	bool "kexec file based system call"
2013	select KEXEC_CORE
2014	select BUILD_BIN2C
2015	depends on X86_64
2016	depends on CRYPTO=y
2017	depends on CRYPTO_SHA256=y
2018	help
2019	  This is new version of kexec system call. This system call is
2020	  file based and takes file descriptors as system call argument
2021	  for kernel and initramfs as opposed to list of segments as
2022	  accepted by previous system call.
2023
2024config ARCH_HAS_KEXEC_PURGATORY
2025	def_bool KEXEC_FILE
2026
2027config KEXEC_SIG
2028	bool "Verify kernel signature during kexec_file_load() syscall"
2029	depends on KEXEC_FILE
2030	help
2031
2032	  This option makes the kexec_file_load() syscall check for a valid
2033	  signature of the kernel image.  The image can still be loaded without
2034	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2035	  there's a signature that we can check, then it must be valid.
2036
2037	  In addition to this option, you need to enable signature
2038	  verification for the corresponding kernel image type being
2039	  loaded in order for this to work.
2040
2041config KEXEC_SIG_FORCE
2042	bool "Require a valid signature in kexec_file_load() syscall"
2043	depends on KEXEC_SIG
2044	help
2045	  This option makes kernel signature verification mandatory for
2046	  the kexec_file_load() syscall.
2047
2048config KEXEC_BZIMAGE_VERIFY_SIG
2049	bool "Enable bzImage signature verification support"
2050	depends on KEXEC_SIG
2051	depends on SIGNED_PE_FILE_VERIFICATION
2052	select SYSTEM_TRUSTED_KEYRING
2053	help
2054	  Enable bzImage signature verification support.
2055
2056config CRASH_DUMP
2057	bool "kernel crash dumps"
2058	depends on X86_64 || (X86_32 && HIGHMEM)
2059	help
2060	  Generate crash dump after being started by kexec.
2061	  This should be normally only set in special crash dump kernels
2062	  which are loaded in the main kernel with kexec-tools into
2063	  a specially reserved region and then later executed after
2064	  a crash by kdump/kexec. The crash dump kernel must be compiled
2065	  to a memory address not used by the main kernel or BIOS using
2066	  PHYSICAL_START, or it must be built as a relocatable image
2067	  (CONFIG_RELOCATABLE=y).
2068	  For more details see Documentation/admin-guide/kdump/kdump.rst
2069
2070config KEXEC_JUMP
2071	bool "kexec jump"
2072	depends on KEXEC && HIBERNATION
2073	help
2074	  Jump between original kernel and kexeced kernel and invoke
2075	  code in physical address mode via KEXEC
2076
2077config PHYSICAL_START
2078	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2079	default "0x1000000"
2080	help
2081	  This gives the physical address where the kernel is loaded.
2082
2083	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2084	  bzImage will decompress itself to above physical address and
2085	  run from there. Otherwise, bzImage will run from the address where
2086	  it has been loaded by the boot loader and will ignore above physical
2087	  address.
2088
2089	  In normal kdump cases one does not have to set/change this option
2090	  as now bzImage can be compiled as a completely relocatable image
2091	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2092	  address. This option is mainly useful for the folks who don't want
2093	  to use a bzImage for capturing the crash dump and want to use a
2094	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2095	  to be specifically compiled to run from a specific memory area
2096	  (normally a reserved region) and this option comes handy.
2097
2098	  So if you are using bzImage for capturing the crash dump,
2099	  leave the value here unchanged to 0x1000000 and set
2100	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2101	  for capturing the crash dump change this value to start of
2102	  the reserved region.  In other words, it can be set based on
2103	  the "X" value as specified in the "crashkernel=YM@XM"
2104	  command line boot parameter passed to the panic-ed
2105	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2106	  for more details about crash dumps.
2107
2108	  Usage of bzImage for capturing the crash dump is recommended as
2109	  one does not have to build two kernels. Same kernel can be used
2110	  as production kernel and capture kernel. Above option should have
2111	  gone away after relocatable bzImage support is introduced. But it
2112	  is present because there are users out there who continue to use
2113	  vmlinux for dump capture. This option should go away down the
2114	  line.
2115
2116	  Don't change this unless you know what you are doing.
2117
2118config RELOCATABLE
2119	bool "Build a relocatable kernel"
2120	default y
2121	help
2122	  This builds a kernel image that retains relocation information
2123	  so it can be loaded someplace besides the default 1MB.
2124	  The relocations tend to make the kernel binary about 10% larger,
2125	  but are discarded at runtime.
2126
2127	  One use is for the kexec on panic case where the recovery kernel
2128	  must live at a different physical address than the primary
2129	  kernel.
2130
2131	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2132	  it has been loaded at and the compile time physical address
2133	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2134
2135config RANDOMIZE_BASE
2136	bool "Randomize the address of the kernel image (KASLR)"
2137	depends on RELOCATABLE
2138	default y
2139	help
2140	  In support of Kernel Address Space Layout Randomization (KASLR),
2141	  this randomizes the physical address at which the kernel image
2142	  is decompressed and the virtual address where the kernel
2143	  image is mapped, as a security feature that deters exploit
2144	  attempts relying on knowledge of the location of kernel
2145	  code internals.
2146
2147	  On 64-bit, the kernel physical and virtual addresses are
2148	  randomized separately. The physical address will be anywhere
2149	  between 16MB and the top of physical memory (up to 64TB). The
2150	  virtual address will be randomized from 16MB up to 1GB (9 bits
2151	  of entropy). Note that this also reduces the memory space
2152	  available to kernel modules from 1.5GB to 1GB.
2153
2154	  On 32-bit, the kernel physical and virtual addresses are
2155	  randomized together. They will be randomized from 16MB up to
2156	  512MB (8 bits of entropy).
2157
2158	  Entropy is generated using the RDRAND instruction if it is
2159	  supported. If RDTSC is supported, its value is mixed into
2160	  the entropy pool as well. If neither RDRAND nor RDTSC are
2161	  supported, then entropy is read from the i8254 timer. The
2162	  usable entropy is limited by the kernel being built using
2163	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2164	  minimum of 2MB. As a result, only 10 bits of entropy are
2165	  theoretically possible, but the implementations are further
2166	  limited due to memory layouts.
2167
2168	  If unsure, say Y.
2169
2170# Relocation on x86 needs some additional build support
2171config X86_NEED_RELOCS
2172	def_bool y
2173	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2174
2175config PHYSICAL_ALIGN
2176	hex "Alignment value to which kernel should be aligned"
2177	default "0x200000"
2178	range 0x2000 0x1000000 if X86_32
2179	range 0x200000 0x1000000 if X86_64
2180	help
2181	  This value puts the alignment restrictions on physical address
2182	  where kernel is loaded and run from. Kernel is compiled for an
2183	  address which meets above alignment restriction.
2184
2185	  If bootloader loads the kernel at a non-aligned address and
2186	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2187	  address aligned to above value and run from there.
2188
2189	  If bootloader loads the kernel at a non-aligned address and
2190	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2191	  load address and decompress itself to the address it has been
2192	  compiled for and run from there. The address for which kernel is
2193	  compiled already meets above alignment restrictions. Hence the
2194	  end result is that kernel runs from a physical address meeting
2195	  above alignment restrictions.
2196
2197	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2198	  this value must be a multiple of 0x200000.
2199
2200	  Don't change this unless you know what you are doing.
2201
2202config DYNAMIC_MEMORY_LAYOUT
2203	bool
2204	help
2205	  This option makes base addresses of vmalloc and vmemmap as well as
2206	  __PAGE_OFFSET movable during boot.
2207
2208config RANDOMIZE_MEMORY
2209	bool "Randomize the kernel memory sections"
2210	depends on X86_64
2211	depends on RANDOMIZE_BASE
2212	select DYNAMIC_MEMORY_LAYOUT
2213	default RANDOMIZE_BASE
2214	help
2215	   Randomizes the base virtual address of kernel memory sections
2216	   (physical memory mapping, vmalloc & vmemmap). This security feature
2217	   makes exploits relying on predictable memory locations less reliable.
2218
2219	   The order of allocations remains unchanged. Entropy is generated in
2220	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2221	   configuration have in average 30,000 different possible virtual
2222	   addresses for each memory section.
2223
2224	   If unsure, say Y.
2225
2226config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2227	hex "Physical memory mapping padding" if EXPERT
2228	depends on RANDOMIZE_MEMORY
2229	default "0xa" if MEMORY_HOTPLUG
2230	default "0x0"
2231	range 0x1 0x40 if MEMORY_HOTPLUG
2232	range 0x0 0x40
2233	help
2234	   Define the padding in terabytes added to the existing physical
2235	   memory size during kernel memory randomization. It is useful
2236	   for memory hotplug support but reduces the entropy available for
2237	   address randomization.
2238
2239	   If unsure, leave at the default value.
2240
2241config HOTPLUG_CPU
2242	def_bool y
2243	depends on SMP
2244
2245config BOOTPARAM_HOTPLUG_CPU0
2246	bool "Set default setting of cpu0_hotpluggable"
2247	depends on HOTPLUG_CPU
2248	help
2249	  Set whether default state of cpu0_hotpluggable is on or off.
2250
2251	  Say Y here to enable CPU0 hotplug by default. If this switch
2252	  is turned on, there is no need to give cpu0_hotplug kernel
2253	  parameter and the CPU0 hotplug feature is enabled by default.
2254
2255	  Please note: there are two known CPU0 dependencies if you want
2256	  to enable the CPU0 hotplug feature either by this switch or by
2257	  cpu0_hotplug kernel parameter.
2258
2259	  First, resume from hibernate or suspend always starts from CPU0.
2260	  So hibernate and suspend are prevented if CPU0 is offline.
2261
2262	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2263	  offline if any interrupt can not migrate out of CPU0. There may
2264	  be other CPU0 dependencies.
2265
2266	  Please make sure the dependencies are under your control before
2267	  you enable this feature.
2268
2269	  Say N if you don't want to enable CPU0 hotplug feature by default.
2270	  You still can enable the CPU0 hotplug feature at boot by kernel
2271	  parameter cpu0_hotplug.
2272
2273config DEBUG_HOTPLUG_CPU0
2274	def_bool n
2275	prompt "Debug CPU0 hotplug"
2276	depends on HOTPLUG_CPU
2277	help
2278	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2279	  soon as possible and boots up userspace with CPU0 offlined. User
2280	  can online CPU0 back after boot time.
2281
2282	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2283	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2284	  compilation or giving cpu0_hotplug kernel parameter at boot.
2285
2286	  If unsure, say N.
2287
2288config COMPAT_VDSO
2289	def_bool n
2290	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2291	depends on COMPAT_32
2292	help
2293	  Certain buggy versions of glibc will crash if they are
2294	  presented with a 32-bit vDSO that is not mapped at the address
2295	  indicated in its segment table.
2296
2297	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2298	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2299	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2300	  the only released version with the bug, but OpenSUSE 9
2301	  contains a buggy "glibc 2.3.2".
2302
2303	  The symptom of the bug is that everything crashes on startup, saying:
2304	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2305
2306	  Saying Y here changes the default value of the vdso32 boot
2307	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2308	  This works around the glibc bug but hurts performance.
2309
2310	  If unsure, say N: if you are compiling your own kernel, you
2311	  are unlikely to be using a buggy version of glibc.
2312
2313choice
2314	prompt "vsyscall table for legacy applications"
2315	depends on X86_64
2316	default LEGACY_VSYSCALL_XONLY
2317	help
2318	  Legacy user code that does not know how to find the vDSO expects
2319	  to be able to issue three syscalls by calling fixed addresses in
2320	  kernel space. Since this location is not randomized with ASLR,
2321	  it can be used to assist security vulnerability exploitation.
2322
2323	  This setting can be changed at boot time via the kernel command
2324	  line parameter vsyscall=[emulate|xonly|none].
2325
2326	  On a system with recent enough glibc (2.14 or newer) and no
2327	  static binaries, you can say None without a performance penalty
2328	  to improve security.
2329
2330	  If unsure, select "Emulate execution only".
2331
2332	config LEGACY_VSYSCALL_EMULATE
2333		bool "Full emulation"
2334		help
2335		  The kernel traps and emulates calls into the fixed vsyscall
2336		  address mapping. This makes the mapping non-executable, but
2337		  it still contains readable known contents, which could be
2338		  used in certain rare security vulnerability exploits. This
2339		  configuration is recommended when using legacy userspace
2340		  that still uses vsyscalls along with legacy binary
2341		  instrumentation tools that require code to be readable.
2342
2343		  An example of this type of legacy userspace is running
2344		  Pin on an old binary that still uses vsyscalls.
2345
2346	config LEGACY_VSYSCALL_XONLY
2347		bool "Emulate execution only"
2348		help
2349		  The kernel traps and emulates calls into the fixed vsyscall
2350		  address mapping and does not allow reads.  This
2351		  configuration is recommended when userspace might use the
2352		  legacy vsyscall area but support for legacy binary
2353		  instrumentation of legacy code is not needed.  It mitigates
2354		  certain uses of the vsyscall area as an ASLR-bypassing
2355		  buffer.
2356
2357	config LEGACY_VSYSCALL_NONE
2358		bool "None"
2359		help
2360		  There will be no vsyscall mapping at all. This will
2361		  eliminate any risk of ASLR bypass due to the vsyscall
2362		  fixed address mapping. Attempts to use the vsyscalls
2363		  will be reported to dmesg, so that either old or
2364		  malicious userspace programs can be identified.
2365
2366endchoice
2367
2368config CMDLINE_BOOL
2369	bool "Built-in kernel command line"
2370	help
2371	  Allow for specifying boot arguments to the kernel at
2372	  build time.  On some systems (e.g. embedded ones), it is
2373	  necessary or convenient to provide some or all of the
2374	  kernel boot arguments with the kernel itself (that is,
2375	  to not rely on the boot loader to provide them.)
2376
2377	  To compile command line arguments into the kernel,
2378	  set this option to 'Y', then fill in the
2379	  boot arguments in CONFIG_CMDLINE.
2380
2381	  Systems with fully functional boot loaders (i.e. non-embedded)
2382	  should leave this option set to 'N'.
2383
2384config CMDLINE
2385	string "Built-in kernel command string"
2386	depends on CMDLINE_BOOL
2387	default ""
2388	help
2389	  Enter arguments here that should be compiled into the kernel
2390	  image and used at boot time.  If the boot loader provides a
2391	  command line at boot time, it is appended to this string to
2392	  form the full kernel command line, when the system boots.
2393
2394	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2395	  change this behavior.
2396
2397	  In most cases, the command line (whether built-in or provided
2398	  by the boot loader) should specify the device for the root
2399	  file system.
2400
2401config CMDLINE_OVERRIDE
2402	bool "Built-in command line overrides boot loader arguments"
2403	depends on CMDLINE_BOOL && CMDLINE != ""
2404	help
2405	  Set this option to 'Y' to have the kernel ignore the boot loader
2406	  command line, and use ONLY the built-in command line.
2407
2408	  This is used to work around broken boot loaders.  This should
2409	  be set to 'N' under normal conditions.
2410
2411config MODIFY_LDT_SYSCALL
2412	bool "Enable the LDT (local descriptor table)" if EXPERT
2413	default y
2414	help
2415	  Linux can allow user programs to install a per-process x86
2416	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2417	  call.  This is required to run 16-bit or segmented code such as
2418	  DOSEMU or some Wine programs.  It is also used by some very old
2419	  threading libraries.
2420
2421	  Enabling this feature adds a small amount of overhead to
2422	  context switches and increases the low-level kernel attack
2423	  surface.  Disabling it removes the modify_ldt(2) system call.
2424
2425	  Saying 'N' here may make sense for embedded or server kernels.
2426
2427source "kernel/livepatch/Kconfig"
2428
2429endmenu
2430
2431config ARCH_HAS_ADD_PAGES
2432	def_bool y
2433	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2434
2435config ARCH_ENABLE_MEMORY_HOTPLUG
2436	def_bool y
2437	depends on X86_64 || (X86_32 && HIGHMEM)
2438
2439config ARCH_ENABLE_MEMORY_HOTREMOVE
2440	def_bool y
2441	depends on MEMORY_HOTPLUG
2442
2443config USE_PERCPU_NUMA_NODE_ID
2444	def_bool y
2445	depends on NUMA
2446
2447config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2448	def_bool y
2449	depends on X86_64 || X86_PAE
2450
2451config ARCH_ENABLE_HUGEPAGE_MIGRATION
2452	def_bool y
2453	depends on X86_64 && HUGETLB_PAGE && MIGRATION
2454
2455config ARCH_ENABLE_THP_MIGRATION
2456	def_bool y
2457	depends on X86_64 && TRANSPARENT_HUGEPAGE
2458
2459menu "Power management and ACPI options"
2460
2461config ARCH_HIBERNATION_HEADER
2462	def_bool y
2463	depends on HIBERNATION
2464
2465source "kernel/power/Kconfig"
2466
2467source "drivers/acpi/Kconfig"
2468
2469source "drivers/sfi/Kconfig"
2470
2471config X86_APM_BOOT
2472	def_bool y
2473	depends on APM
2474
2475menuconfig APM
2476	tristate "APM (Advanced Power Management) BIOS support"
2477	depends on X86_32 && PM_SLEEP
2478	help
2479	  APM is a BIOS specification for saving power using several different
2480	  techniques. This is mostly useful for battery powered laptops with
2481	  APM compliant BIOSes. If you say Y here, the system time will be
2482	  reset after a RESUME operation, the /proc/apm device will provide
2483	  battery status information, and user-space programs will receive
2484	  notification of APM "events" (e.g. battery status change).
2485
2486	  If you select "Y" here, you can disable actual use of the APM
2487	  BIOS by passing the "apm=off" option to the kernel at boot time.
2488
2489	  Note that the APM support is almost completely disabled for
2490	  machines with more than one CPU.
2491
2492	  In order to use APM, you will need supporting software. For location
2493	  and more information, read <file:Documentation/power/apm-acpi.rst>
2494	  and the Battery Powered Linux mini-HOWTO, available from
2495	  <http://www.tldp.org/docs.html#howto>.
2496
2497	  This driver does not spin down disk drives (see the hdparm(8)
2498	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2499	  VESA-compliant "green" monitors.
2500
2501	  This driver does not support the TI 4000M TravelMate and the ACER
2502	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2503	  desktop machines also don't have compliant BIOSes, and this driver
2504	  may cause those machines to panic during the boot phase.
2505
2506	  Generally, if you don't have a battery in your machine, there isn't
2507	  much point in using this driver and you should say N. If you get
2508	  random kernel OOPSes or reboots that don't seem to be related to
2509	  anything, try disabling/enabling this option (or disabling/enabling
2510	  APM in your BIOS).
2511
2512	  Some other things you should try when experiencing seemingly random,
2513	  "weird" problems:
2514
2515	  1) make sure that you have enough swap space and that it is
2516	  enabled.
2517	  2) pass the "no-hlt" option to the kernel
2518	  3) switch on floating point emulation in the kernel and pass
2519	  the "no387" option to the kernel
2520	  4) pass the "floppy=nodma" option to the kernel
2521	  5) pass the "mem=4M" option to the kernel (thereby disabling
2522	  all but the first 4 MB of RAM)
2523	  6) make sure that the CPU is not over clocked.
2524	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2525	  8) disable the cache from your BIOS settings
2526	  9) install a fan for the video card or exchange video RAM
2527	  10) install a better fan for the CPU
2528	  11) exchange RAM chips
2529	  12) exchange the motherboard.
2530
2531	  To compile this driver as a module, choose M here: the
2532	  module will be called apm.
2533
2534if APM
2535
2536config APM_IGNORE_USER_SUSPEND
2537	bool "Ignore USER SUSPEND"
2538	help
2539	  This option will ignore USER SUSPEND requests. On machines with a
2540	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2541	  series notebooks, it is necessary to say Y because of a BIOS bug.
2542
2543config APM_DO_ENABLE
2544	bool "Enable PM at boot time"
2545	help
2546	  Enable APM features at boot time. From page 36 of the APM BIOS
2547	  specification: "When disabled, the APM BIOS does not automatically
2548	  power manage devices, enter the Standby State, enter the Suspend
2549	  State, or take power saving steps in response to CPU Idle calls."
2550	  This driver will make CPU Idle calls when Linux is idle (unless this
2551	  feature is turned off -- see "Do CPU IDLE calls", below). This
2552	  should always save battery power, but more complicated APM features
2553	  will be dependent on your BIOS implementation. You may need to turn
2554	  this option off if your computer hangs at boot time when using APM
2555	  support, or if it beeps continuously instead of suspending. Turn
2556	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2557	  T400CDT. This is off by default since most machines do fine without
2558	  this feature.
2559
2560config APM_CPU_IDLE
2561	depends on CPU_IDLE
2562	bool "Make CPU Idle calls when idle"
2563	help
2564	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2565	  On some machines, this can activate improved power savings, such as
2566	  a slowed CPU clock rate, when the machine is idle. These idle calls
2567	  are made after the idle loop has run for some length of time (e.g.,
2568	  333 mS). On some machines, this will cause a hang at boot time or
2569	  whenever the CPU becomes idle. (On machines with more than one CPU,
2570	  this option does nothing.)
2571
2572config APM_DISPLAY_BLANK
2573	bool "Enable console blanking using APM"
2574	help
2575	  Enable console blanking using the APM. Some laptops can use this to
2576	  turn off the LCD backlight when the screen blanker of the Linux
2577	  virtual console blanks the screen. Note that this is only used by
2578	  the virtual console screen blanker, and won't turn off the backlight
2579	  when using the X Window system. This also doesn't have anything to
2580	  do with your VESA-compliant power-saving monitor. Further, this
2581	  option doesn't work for all laptops -- it might not turn off your
2582	  backlight at all, or it might print a lot of errors to the console,
2583	  especially if you are using gpm.
2584
2585config APM_ALLOW_INTS
2586	bool "Allow interrupts during APM BIOS calls"
2587	help
2588	  Normally we disable external interrupts while we are making calls to
2589	  the APM BIOS as a measure to lessen the effects of a badly behaving
2590	  BIOS implementation.  The BIOS should reenable interrupts if it
2591	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2592	  many of the newer IBM Thinkpads.  If you experience hangs when you
2593	  suspend, try setting this to Y.  Otherwise, say N.
2594
2595endif # APM
2596
2597source "drivers/cpufreq/Kconfig"
2598
2599source "drivers/cpuidle/Kconfig"
2600
2601source "drivers/idle/Kconfig"
2602
2603endmenu
2604
2605
2606menu "Bus options (PCI etc.)"
2607
2608choice
2609	prompt "PCI access mode"
2610	depends on X86_32 && PCI
2611	default PCI_GOANY
2612	help
2613	  On PCI systems, the BIOS can be used to detect the PCI devices and
2614	  determine their configuration. However, some old PCI motherboards
2615	  have BIOS bugs and may crash if this is done. Also, some embedded
2616	  PCI-based systems don't have any BIOS at all. Linux can also try to
2617	  detect the PCI hardware directly without using the BIOS.
2618
2619	  With this option, you can specify how Linux should detect the
2620	  PCI devices. If you choose "BIOS", the BIOS will be used,
2621	  if you choose "Direct", the BIOS won't be used, and if you
2622	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2623	  If you choose "Any", the kernel will try MMCONFIG, then the
2624	  direct access method and falls back to the BIOS if that doesn't
2625	  work. If unsure, go with the default, which is "Any".
2626
2627config PCI_GOBIOS
2628	bool "BIOS"
2629
2630config PCI_GOMMCONFIG
2631	bool "MMConfig"
2632
2633config PCI_GODIRECT
2634	bool "Direct"
2635
2636config PCI_GOOLPC
2637	bool "OLPC XO-1"
2638	depends on OLPC
2639
2640config PCI_GOANY
2641	bool "Any"
2642
2643endchoice
2644
2645config PCI_BIOS
2646	def_bool y
2647	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2648
2649# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2650config PCI_DIRECT
2651	def_bool y
2652	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2653
2654config PCI_MMCONFIG
2655	bool "Support mmconfig PCI config space access" if X86_64
2656	default y
2657	depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2658	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2659
2660config PCI_OLPC
2661	def_bool y
2662	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2663
2664config PCI_XEN
2665	def_bool y
2666	depends on PCI && XEN
2667	select SWIOTLB_XEN
2668
2669config MMCONF_FAM10H
2670	def_bool y
2671	depends on X86_64 && PCI_MMCONFIG && ACPI
2672
2673config PCI_CNB20LE_QUIRK
2674	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2675	depends on PCI
2676	help
2677	  Read the PCI windows out of the CNB20LE host bridge. This allows
2678	  PCI hotplug to work on systems with the CNB20LE chipset which do
2679	  not have ACPI.
2680
2681	  There's no public spec for this chipset, and this functionality
2682	  is known to be incomplete.
2683
2684	  You should say N unless you know you need this.
2685
2686config ISA_BUS
2687	bool "ISA bus support on modern systems" if EXPERT
2688	help
2689	  Expose ISA bus device drivers and options available for selection and
2690	  configuration. Enable this option if your target machine has an ISA
2691	  bus. ISA is an older system, displaced by PCI and newer bus
2692	  architectures -- if your target machine is modern, it probably does
2693	  not have an ISA bus.
2694
2695	  If unsure, say N.
2696
2697# x86_64 have no ISA slots, but can have ISA-style DMA.
2698config ISA_DMA_API
2699	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2700	default y
2701	help
2702	  Enables ISA-style DMA support for devices requiring such controllers.
2703	  If unsure, say Y.
2704
2705if X86_32
2706
2707config ISA
2708	bool "ISA support"
2709	help
2710	  Find out whether you have ISA slots on your motherboard.  ISA is the
2711	  name of a bus system, i.e. the way the CPU talks to the other stuff
2712	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2713	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2714	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2715
2716config SCx200
2717	tristate "NatSemi SCx200 support"
2718	help
2719	  This provides basic support for National Semiconductor's
2720	  (now AMD's) Geode processors.  The driver probes for the
2721	  PCI-IDs of several on-chip devices, so its a good dependency
2722	  for other scx200_* drivers.
2723
2724	  If compiled as a module, the driver is named scx200.
2725
2726config SCx200HR_TIMER
2727	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2728	depends on SCx200
2729	default y
2730	help
2731	  This driver provides a clocksource built upon the on-chip
2732	  27MHz high-resolution timer.  Its also a workaround for
2733	  NSC Geode SC-1100's buggy TSC, which loses time when the
2734	  processor goes idle (as is done by the scheduler).  The
2735	  other workaround is idle=poll boot option.
2736
2737config OLPC
2738	bool "One Laptop Per Child support"
2739	depends on !X86_PAE
2740	select GPIOLIB
2741	select OF
2742	select OF_PROMTREE
2743	select IRQ_DOMAIN
2744	select OLPC_EC
2745	help
2746	  Add support for detecting the unique features of the OLPC
2747	  XO hardware.
2748
2749config OLPC_XO1_PM
2750	bool "OLPC XO-1 Power Management"
2751	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2752	help
2753	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2754
2755config OLPC_XO1_RTC
2756	bool "OLPC XO-1 Real Time Clock"
2757	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2758	help
2759	  Add support for the XO-1 real time clock, which can be used as a
2760	  programmable wakeup source.
2761
2762config OLPC_XO1_SCI
2763	bool "OLPC XO-1 SCI extras"
2764	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2765	depends on INPUT=y
2766	select POWER_SUPPLY
2767	help
2768	  Add support for SCI-based features of the OLPC XO-1 laptop:
2769	   - EC-driven system wakeups
2770	   - Power button
2771	   - Ebook switch
2772	   - Lid switch
2773	   - AC adapter status updates
2774	   - Battery status updates
2775
2776config OLPC_XO15_SCI
2777	bool "OLPC XO-1.5 SCI extras"
2778	depends on OLPC && ACPI
2779	select POWER_SUPPLY
2780	help
2781	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2782	   - EC-driven system wakeups
2783	   - AC adapter status updates
2784	   - Battery status updates
2785
2786config ALIX
2787	bool "PCEngines ALIX System Support (LED setup)"
2788	select GPIOLIB
2789	help
2790	  This option enables system support for the PCEngines ALIX.
2791	  At present this just sets up LEDs for GPIO control on
2792	  ALIX2/3/6 boards.  However, other system specific setup should
2793	  get added here.
2794
2795	  Note: You must still enable the drivers for GPIO and LED support
2796	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2797
2798	  Note: You have to set alix.force=1 for boards with Award BIOS.
2799
2800config NET5501
2801	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2802	select GPIOLIB
2803	help
2804	  This option enables system support for the Soekris Engineering net5501.
2805
2806config GEOS
2807	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2808	select GPIOLIB
2809	depends on DMI
2810	help
2811	  This option enables system support for the Traverse Technologies GEOS.
2812
2813config TS5500
2814	bool "Technologic Systems TS-5500 platform support"
2815	depends on MELAN
2816	select CHECK_SIGNATURE
2817	select NEW_LEDS
2818	select LEDS_CLASS
2819	help
2820	  This option enables system support for the Technologic Systems TS-5500.
2821
2822endif # X86_32
2823
2824config AMD_NB
2825	def_bool y
2826	depends on CPU_SUP_AMD && PCI
2827
2828config X86_SYSFB
2829	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2830	help
2831	  Firmwares often provide initial graphics framebuffers so the BIOS,
2832	  bootloader or kernel can show basic video-output during boot for
2833	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2834	  Extensions and EFI-framebuffers for this, which are mostly limited
2835	  to x86.
2836	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2837	  framebuffers so the new generic system-framebuffer drivers can be
2838	  used on x86. If the framebuffer is not compatible with the generic
2839	  modes, it is advertised as fallback platform framebuffer so legacy
2840	  drivers like efifb, vesafb and uvesafb can pick it up.
2841	  If this option is not selected, all system framebuffers are always
2842	  marked as fallback platform framebuffers as usual.
2843
2844	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2845	  not be able to pick up generic system framebuffers if this option
2846	  is selected. You are highly encouraged to enable simplefb as
2847	  replacement if you select this option. simplefb can correctly deal
2848	  with generic system framebuffers. But you should still keep vesafb
2849	  and others enabled as fallback if a system framebuffer is
2850	  incompatible with simplefb.
2851
2852	  If unsure, say Y.
2853
2854endmenu
2855
2856
2857menu "Binary Emulations"
2858
2859config IA32_EMULATION
2860	bool "IA32 Emulation"
2861	depends on X86_64
2862	select ARCH_WANT_OLD_COMPAT_IPC
2863	select BINFMT_ELF
2864	select COMPAT_OLD_SIGACTION
2865	help
2866	  Include code to run legacy 32-bit programs under a
2867	  64-bit kernel. You should likely turn this on, unless you're
2868	  100% sure that you don't have any 32-bit programs left.
2869
2870config IA32_AOUT
2871	tristate "IA32 a.out support"
2872	depends on IA32_EMULATION
2873	depends on BROKEN
2874	help
2875	  Support old a.out binaries in the 32bit emulation.
2876
2877config X86_X32
2878	bool "x32 ABI for 64-bit mode"
2879	depends on X86_64
2880	help
2881	  Include code to run binaries for the x32 native 32-bit ABI
2882	  for 64-bit processors.  An x32 process gets access to the
2883	  full 64-bit register file and wide data path while leaving
2884	  pointers at 32 bits for smaller memory footprint.
2885
2886	  You will need a recent binutils (2.22 or later) with
2887	  elf32_x86_64 support enabled to compile a kernel with this
2888	  option set.
2889
2890config COMPAT_32
2891	def_bool y
2892	depends on IA32_EMULATION || X86_32
2893	select HAVE_UID16
2894	select OLD_SIGSUSPEND3
2895
2896config COMPAT
2897	def_bool y
2898	depends on IA32_EMULATION || X86_X32
2899
2900if COMPAT
2901config COMPAT_FOR_U64_ALIGNMENT
2902	def_bool y
2903
2904config SYSVIPC_COMPAT
2905	def_bool y
2906	depends on SYSVIPC
2907endif
2908
2909endmenu
2910
2911
2912config HAVE_ATOMIC_IOMAP
2913	def_bool y
2914	depends on X86_32
2915
2916source "drivers/firmware/Kconfig"
2917
2918source "arch/x86/kvm/Kconfig"
2919
2920source "arch/x86/Kconfig.assembler"
2921