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1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select HAVE_DEBUG_STACKOVERFLOW
18	select MODULES_USE_ELF_REL
19	select OLD_SIGACTION
20	select GENERIC_VDSO_32
21	select ARCH_SPLIT_ARG64
22
23config X86_64
24	def_bool y
25	depends on 64BIT
26	# Options that are inherently 64-bit kernel only:
27	select ARCH_HAS_GIGANTIC_PAGE
28	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
29	select ARCH_USE_CMPXCHG_LOCKREF
30	select HAVE_ARCH_SOFT_DIRTY
31	select MODULES_USE_ELF_RELA
32	select NEED_DMA_MAP_STATE
33	select SWIOTLB
34
35config FORCE_DYNAMIC_FTRACE
36	def_bool y
37	depends on X86_32
38	depends on FUNCTION_TRACER
39	select DYNAMIC_FTRACE
40	help
41	 We keep the static function tracing (!DYNAMIC_FTRACE) around
42	 in order to test the non static function tracing in the
43	 generic code, as other architectures still use it. But we
44	 only need to keep it around for x86_64. No need to keep it
45	 for x86_32. For x86_32, force DYNAMIC_FTRACE.
46#
47# Arch settings
48#
49# ( Note that options that are marked 'if X86_64' could in principle be
50#   ported to 32-bit as well. )
51#
52config X86
53	def_bool y
54	#
55	# Note: keep this list sorted alphabetically
56	#
57	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
58	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
59	select ARCH_32BIT_OFF_T			if X86_32
60	select ARCH_CLOCKSOURCE_INIT
61	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
62	select ARCH_HAS_CPU_FINALIZE_INIT
63	select ARCH_HAS_CACHE_LINE_SIZE
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_NUMA_BALANCING	if X86_64
98	select ARCH_USE_BUILTIN_BSWAP
99	select ARCH_USE_QUEUED_RWLOCKS
100	select ARCH_USE_QUEUED_SPINLOCKS
101	select ARCH_USE_SYM_ANNOTATIONS
102	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
103	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
104	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
105	select ARCH_WANT_HUGE_PMD_SHARE
106	select ARCH_WANT_LD_ORPHAN_WARN
107	select ARCH_WANTS_THP_SWAP		if X86_64
108	select BUILDTIME_TABLE_SORT
109	select CLKEVT_I8253
110	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
111	select CLOCKSOURCE_WATCHDOG
112	select DCACHE_WORD_ACCESS
113	select EDAC_ATOMIC_SCRUB
114	select EDAC_SUPPORT
115	select GENERIC_CLOCKEVENTS
116	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
117	select GENERIC_CLOCKEVENTS_MIN_ADJUST
118	select GENERIC_CMOS_UPDATE
119	select GENERIC_CPU_AUTOPROBE
120	select GENERIC_CPU_VULNERABILITIES
121	select GENERIC_EARLY_IOREMAP
122	select GENERIC_ENTRY
123	select GENERIC_FIND_FIRST_BIT
124	select GENERIC_IOMAP
125	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
126	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
127	select GENERIC_IRQ_MIGRATION		if SMP
128	select GENERIC_IRQ_PROBE
129	select GENERIC_IRQ_RESERVATION_MODE
130	select GENERIC_IRQ_SHOW
131	select GENERIC_PENDING_IRQ		if SMP
132	select GENERIC_PTDUMP
133	select GENERIC_SMP_IDLE_THREAD
134	select GENERIC_STRNCPY_FROM_USER
135	select GENERIC_STRNLEN_USER
136	select GENERIC_TIME_VSYSCALL
137	select GENERIC_GETTIMEOFDAY
138	select GENERIC_VDSO_TIME_NS
139	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
140	select HARDIRQS_SW_RESEND
141	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
142	select HAVE_ACPI_APEI			if ACPI
143	select HAVE_ACPI_APEI_NMI		if ACPI
144	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
145	select HAVE_ARCH_AUDITSYSCALL
146	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
147	select HAVE_ARCH_JUMP_LABEL
148	select HAVE_ARCH_JUMP_LABEL_RELATIVE
149	select HAVE_ARCH_KASAN			if X86_64
150	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
151	select HAVE_ARCH_KGDB
152	select HAVE_ARCH_MMAP_RND_BITS		if MMU
153	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
154	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
155	select HAVE_ARCH_PREL32_RELOCATIONS
156	select HAVE_ARCH_SECCOMP_FILTER
157	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
158	select HAVE_ARCH_STACKLEAK
159	select HAVE_ARCH_TRACEHOOK
160	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
161	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
162	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
163	select HAVE_ARCH_VMAP_STACK		if X86_64
164	select HAVE_ARCH_WITHIN_STACK_FRAMES
165	select HAVE_ASM_MODVERSIONS
166	select HAVE_CMPXCHG_DOUBLE
167	select HAVE_CMPXCHG_LOCAL
168	select HAVE_CONTEXT_TRACKING		if X86_64
169	select HAVE_C_RECORDMCOUNT
170	select HAVE_DEBUG_KMEMLEAK
171	select HAVE_DMA_CONTIGUOUS
172	select HAVE_DYNAMIC_FTRACE
173	select HAVE_DYNAMIC_FTRACE_WITH_REGS
174	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
175	select HAVE_EBPF_JIT
176	select HAVE_EFFICIENT_UNALIGNED_ACCESS
177	select HAVE_EISA
178	select HAVE_EXIT_THREAD
179	select HAVE_FAST_GUP
180	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
181	select HAVE_FTRACE_MCOUNT_RECORD
182	select HAVE_FUNCTION_GRAPH_TRACER
183	select HAVE_FUNCTION_TRACER
184	select HAVE_GCC_PLUGINS
185	select HAVE_HW_BREAKPOINT
186	select HAVE_IDE
187	select HAVE_IOREMAP_PROT
188	select HAVE_IRQ_TIME_ACCOUNTING
189	select HAVE_KERNEL_BZIP2
190	select HAVE_KERNEL_GZIP
191	select HAVE_KERNEL_LZ4
192	select HAVE_KERNEL_LZMA
193	select HAVE_KERNEL_LZO
194	select HAVE_KERNEL_XZ
195	select HAVE_KERNEL_ZSTD
196	select HAVE_KPROBES
197	select HAVE_KPROBES_ON_FTRACE
198	select HAVE_FUNCTION_ERROR_INJECTION
199	select HAVE_KRETPROBES
200	select HAVE_KVM
201	select HAVE_LIVEPATCH			if X86_64
202	select HAVE_MIXED_BREAKPOINTS_REGS
203	select HAVE_MOD_ARCH_SPECIFIC
204	select HAVE_MOVE_PMD
205	select HAVE_NMI
206	select HAVE_OPROFILE
207	select HAVE_OPTPROBES
208	select HAVE_PCSPKR_PLATFORM
209	select HAVE_PERF_EVENTS
210	select HAVE_PERF_EVENTS_NMI
211	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
212	select HAVE_PCI
213	select HAVE_PERF_REGS
214	select HAVE_PERF_USER_STACK_DUMP
215	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
216	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
217	select HAVE_REGS_AND_STACK_ACCESS_API
218	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
219	select HAVE_FUNCTION_ARG_ACCESS_API
220	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
221	select HAVE_STACK_VALIDATION		if X86_64
222	select HAVE_STATIC_CALL
223	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
224	select HAVE_RSEQ
225	select HAVE_SYSCALL_TRACEPOINTS
226	select HAVE_UNSTABLE_SCHED_CLOCK
227	select HAVE_USER_RETURN_NOTIFIER
228	select HAVE_GENERIC_VDSO
229	select HOTPLUG_SMT			if SMP
230	select IRQ_FORCED_THREADING
231	select NEED_SG_DMA_LENGTH
232	select PCI_DOMAINS			if PCI
233	select PCI_LOCKLESS_CONFIG		if PCI
234	select PERF_EVENTS
235	select RTC_LIB
236	select RTC_MC146818_LIB
237	select SPARSE_IRQ
238	select SRCU
239	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
240	select SYSCTL_EXCEPTION_TRACE
241	select THREAD_INFO_IN_TASK
242	select USER_STACKTRACE_SUPPORT
243	select VIRT_TO_BUS
244	select HAVE_ARCH_KCSAN			if X86_64
245	select X86_FEATURE_NAMES		if PROC_FS
246	select PROC_PID_ARCH_STATUS		if PROC_FS
247	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
248
249config INSTRUCTION_DECODER
250	def_bool y
251	depends on KPROBES || PERF_EVENTS || UPROBES
252
253config OUTPUT_FORMAT
254	string
255	default "elf32-i386" if X86_32
256	default "elf64-x86-64" if X86_64
257
258config LOCKDEP_SUPPORT
259	def_bool y
260
261config STACKTRACE_SUPPORT
262	def_bool y
263
264config MMU
265	def_bool y
266
267config ARCH_MMAP_RND_BITS_MIN
268	default 28 if 64BIT
269	default 8
270
271config ARCH_MMAP_RND_BITS_MAX
272	default 32 if 64BIT
273	default 16
274
275config ARCH_MMAP_RND_COMPAT_BITS_MIN
276	default 8
277
278config ARCH_MMAP_RND_COMPAT_BITS_MAX
279	default 16
280
281config SBUS
282	bool
283
284config GENERIC_ISA_DMA
285	def_bool y
286	depends on ISA_DMA_API
287
288config GENERIC_BUG
289	def_bool y
290	depends on BUG
291	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
292
293config GENERIC_BUG_RELATIVE_POINTERS
294	bool
295
296config ARCH_MAY_HAVE_PC_FDC
297	def_bool y
298	depends on ISA_DMA_API
299
300config GENERIC_CALIBRATE_DELAY
301	def_bool y
302
303config ARCH_HAS_CPU_RELAX
304	def_bool y
305
306config ARCH_HAS_FILTER_PGPROT
307	def_bool y
308
309config HAVE_SETUP_PER_CPU_AREA
310	def_bool y
311
312config NEED_PER_CPU_EMBED_FIRST_CHUNK
313	def_bool y
314
315config NEED_PER_CPU_PAGE_FIRST_CHUNK
316	def_bool y
317
318config ARCH_HIBERNATION_POSSIBLE
319	def_bool y
320
321config ARCH_SUSPEND_POSSIBLE
322	def_bool y
323
324config ARCH_WANT_GENERAL_HUGETLB
325	def_bool y
326
327config ZONE_DMA32
328	def_bool y if X86_64
329
330config AUDIT_ARCH
331	def_bool y if X86_64
332
333config ARCH_SUPPORTS_DEBUG_PAGEALLOC
334	def_bool y
335
336config KASAN_SHADOW_OFFSET
337	hex
338	depends on KASAN
339	default 0xdffffc0000000000
340
341config HAVE_INTEL_TXT
342	def_bool y
343	depends on INTEL_IOMMU && ACPI
344
345config X86_32_SMP
346	def_bool y
347	depends on X86_32 && SMP
348
349config X86_64_SMP
350	def_bool y
351	depends on X86_64 && SMP
352
353config X86_32_LAZY_GS
354	def_bool y
355	depends on X86_32 && !STACKPROTECTOR
356
357config ARCH_SUPPORTS_UPROBES
358	def_bool y
359
360config FIX_EARLYCON_MEM
361	def_bool y
362
363config DYNAMIC_PHYSICAL_MASK
364	bool
365
366config PGTABLE_LEVELS
367	int
368	default 5 if X86_5LEVEL
369	default 4 if X86_64
370	default 3 if X86_PAE
371	default 2
372
373config CC_HAS_SANE_STACKPROTECTOR
374	bool
375	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
376	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
377	help
378	   We have to make sure stack protector is unconditionally disabled if
379	   the compiler produces broken code.
380
381menu "Processor type and features"
382
383config ZONE_DMA
384	bool "DMA memory allocation support" if EXPERT
385	default y
386	help
387	  DMA memory allocation support allows devices with less than 32-bit
388	  addressing to allocate within the first 16MB of address space.
389	  Disable if no such devices will be used.
390
391	  If unsure, say Y.
392
393config SMP
394	bool "Symmetric multi-processing support"
395	help
396	  This enables support for systems with more than one CPU. If you have
397	  a system with only one CPU, say N. If you have a system with more
398	  than one CPU, say Y.
399
400	  If you say N here, the kernel will run on uni- and multiprocessor
401	  machines, but will use only one CPU of a multiprocessor machine. If
402	  you say Y here, the kernel will run on many, but not all,
403	  uniprocessor machines. On a uniprocessor machine, the kernel
404	  will run faster if you say N here.
405
406	  Note that if you say Y here and choose architecture "586" or
407	  "Pentium" under "Processor family", the kernel will not work on 486
408	  architectures. Similarly, multiprocessor kernels for the "PPro"
409	  architecture may not work on all Pentium based boards.
410
411	  People using multiprocessor machines who say Y here should also say
412	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
413	  Management" code will be disabled if you say Y here.
414
415	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
416	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
417	  <http://www.tldp.org/docs.html#howto>.
418
419	  If you don't know what to do here, say N.
420
421config X86_FEATURE_NAMES
422	bool "Processor feature human-readable names" if EMBEDDED
423	default y
424	help
425	  This option compiles in a table of x86 feature bits and corresponding
426	  names.  This is required to support /proc/cpuinfo and a few kernel
427	  messages.  You can disable this to save space, at the expense of
428	  making those few kernel messages show numeric feature bits instead.
429
430	  If in doubt, say Y.
431
432config X86_X2APIC
433	bool "Support x2apic"
434	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
435	help
436	  This enables x2apic support on CPUs that have this feature.
437
438	  This allows 32-bit apic IDs (so it can support very large systems),
439	  and accesses the local apic via MSRs not via mmio.
440
441	  If you don't know what to do here, say N.
442
443config X86_MPPARSE
444	bool "Enable MPS table" if ACPI || SFI
445	default y
446	depends on X86_LOCAL_APIC
447	help
448	  For old smp systems that do not have proper acpi support. Newer systems
449	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
450
451config GOLDFISH
452	def_bool y
453	depends on X86_GOLDFISH
454
455config X86_CPU_RESCTRL
456	bool "x86 CPU resource control support"
457	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
458	select KERNFS
459	select PROC_CPU_RESCTRL		if PROC_FS
460	help
461	  Enable x86 CPU resource control support.
462
463	  Provide support for the allocation and monitoring of system resources
464	  usage by the CPU.
465
466	  Intel calls this Intel Resource Director Technology
467	  (Intel(R) RDT). More information about RDT can be found in the
468	  Intel x86 Architecture Software Developer Manual.
469
470	  AMD calls this AMD Platform Quality of Service (AMD QoS).
471	  More information about AMD QoS can be found in the AMD64 Technology
472	  Platform Quality of Service Extensions manual.
473
474	  Say N if unsure.
475
476if X86_32
477config X86_BIGSMP
478	bool "Support for big SMP systems with more than 8 CPUs"
479	depends on SMP
480	help
481	  This option is needed for the systems that have more than 8 CPUs.
482
483config X86_EXTENDED_PLATFORM
484	bool "Support for extended (non-PC) x86 platforms"
485	default y
486	help
487	  If you disable this option then the kernel will only support
488	  standard PC platforms. (which covers the vast majority of
489	  systems out there.)
490
491	  If you enable this option then you'll be able to select support
492	  for the following (non-PC) 32 bit x86 platforms:
493		Goldfish (Android emulator)
494		AMD Elan
495		RDC R-321x SoC
496		SGI 320/540 (Visual Workstation)
497		STA2X11-based (e.g. Northville)
498		Moorestown MID devices
499
500	  If you have one of these systems, or if you want to build a
501	  generic distribution kernel, say Y here - otherwise say N.
502endif
503
504if X86_64
505config X86_EXTENDED_PLATFORM
506	bool "Support for extended (non-PC) x86 platforms"
507	default y
508	help
509	  If you disable this option then the kernel will only support
510	  standard PC platforms. (which covers the vast majority of
511	  systems out there.)
512
513	  If you enable this option then you'll be able to select support
514	  for the following (non-PC) 64 bit x86 platforms:
515		Numascale NumaChip
516		ScaleMP vSMP
517		SGI Ultraviolet
518
519	  If you have one of these systems, or if you want to build a
520	  generic distribution kernel, say Y here - otherwise say N.
521endif
522# This is an alphabetically sorted list of 64 bit extended platforms
523# Please maintain the alphabetic order if and when there are additions
524config X86_NUMACHIP
525	bool "Numascale NumaChip"
526	depends on X86_64
527	depends on X86_EXTENDED_PLATFORM
528	depends on NUMA
529	depends on SMP
530	depends on X86_X2APIC
531	depends on PCI_MMCONFIG
532	help
533	  Adds support for Numascale NumaChip large-SMP systems. Needed to
534	  enable more than ~168 cores.
535	  If you don't have one of these, you should say N here.
536
537config X86_VSMP
538	bool "ScaleMP vSMP"
539	select HYPERVISOR_GUEST
540	select PARAVIRT
541	depends on X86_64 && PCI
542	depends on X86_EXTENDED_PLATFORM
543	depends on SMP
544	help
545	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
546	  supposed to run on these EM64T-based machines.  Only choose this option
547	  if you have one of these machines.
548
549config X86_UV
550	bool "SGI Ultraviolet"
551	depends on X86_64
552	depends on X86_EXTENDED_PLATFORM
553	depends on NUMA
554	depends on EFI
555	depends on KEXEC_CORE
556	depends on X86_X2APIC
557	depends on PCI
558	help
559	  This option is needed in order to support SGI Ultraviolet systems.
560	  If you don't have one of these, you should say N here.
561
562# Following is an alphabetically sorted list of 32 bit extended platforms
563# Please maintain the alphabetic order if and when there are additions
564
565config X86_GOLDFISH
566	bool "Goldfish (Virtual Platform)"
567	depends on X86_EXTENDED_PLATFORM
568	help
569	 Enable support for the Goldfish virtual platform used primarily
570	 for Android development. Unless you are building for the Android
571	 Goldfish emulator say N here.
572
573config X86_INTEL_CE
574	bool "CE4100 TV platform"
575	depends on PCI
576	depends on PCI_GODIRECT
577	depends on X86_IO_APIC
578	depends on X86_32
579	depends on X86_EXTENDED_PLATFORM
580	select X86_REBOOTFIXUPS
581	select OF
582	select OF_EARLY_FLATTREE
583	help
584	  Select for the Intel CE media processor (CE4100) SOC.
585	  This option compiles in support for the CE4100 SOC for settop
586	  boxes and media devices.
587
588config X86_INTEL_MID
589	bool "Intel MID platform support"
590	depends on X86_EXTENDED_PLATFORM
591	depends on X86_PLATFORM_DEVICES
592	depends on PCI
593	depends on X86_64 || (PCI_GOANY && X86_32)
594	depends on X86_IO_APIC
595	select SFI
596	select I2C
597	select DW_APB_TIMER
598	select APB_TIMER
599	select INTEL_SCU_PCI
600	select MFD_INTEL_MSIC
601	help
602	  Select to build a kernel capable of supporting Intel MID (Mobile
603	  Internet Device) platform systems which do not have the PCI legacy
604	  interfaces. If you are building for a PC class system say N here.
605
606	  Intel MID platforms are based on an Intel processor and chipset which
607	  consume less power than most of the x86 derivatives.
608
609config X86_INTEL_QUARK
610	bool "Intel Quark platform support"
611	depends on X86_32
612	depends on X86_EXTENDED_PLATFORM
613	depends on X86_PLATFORM_DEVICES
614	depends on X86_TSC
615	depends on PCI
616	depends on PCI_GOANY
617	depends on X86_IO_APIC
618	select IOSF_MBI
619	select INTEL_IMR
620	select COMMON_CLK
621	help
622	  Select to include support for Quark X1000 SoC.
623	  Say Y here if you have a Quark based system such as the Arduino
624	  compatible Intel Galileo.
625
626config X86_INTEL_LPSS
627	bool "Intel Low Power Subsystem Support"
628	depends on X86 && ACPI && PCI
629	select COMMON_CLK
630	select PINCTRL
631	select IOSF_MBI
632	help
633	  Select to build support for Intel Low Power Subsystem such as
634	  found on Intel Lynxpoint PCH. Selecting this option enables
635	  things like clock tree (common clock framework) and pincontrol
636	  which are needed by the LPSS peripheral drivers.
637
638config X86_AMD_PLATFORM_DEVICE
639	bool "AMD ACPI2Platform devices support"
640	depends on ACPI
641	select COMMON_CLK
642	select PINCTRL
643	help
644	  Select to interpret AMD specific ACPI device to platform device
645	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
646	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
647	  implemented under PINCTRL subsystem.
648
649config IOSF_MBI
650	tristate "Intel SoC IOSF Sideband support for SoC platforms"
651	depends on PCI
652	help
653	  This option enables sideband register access support for Intel SoC
654	  platforms. On these platforms the IOSF sideband is used in lieu of
655	  MSR's for some register accesses, mostly but not limited to thermal
656	  and power. Drivers may query the availability of this device to
657	  determine if they need the sideband in order to work on these
658	  platforms. The sideband is available on the following SoC products.
659	  This list is not meant to be exclusive.
660	   - BayTrail
661	   - Braswell
662	   - Quark
663
664	  You should say Y if you are running a kernel on one of these SoC's.
665
666config IOSF_MBI_DEBUG
667	bool "Enable IOSF sideband access through debugfs"
668	depends on IOSF_MBI && DEBUG_FS
669	help
670	  Select this option to expose the IOSF sideband access registers (MCR,
671	  MDR, MCRX) through debugfs to write and read register information from
672	  different units on the SoC. This is most useful for obtaining device
673	  state information for debug and analysis. As this is a general access
674	  mechanism, users of this option would have specific knowledge of the
675	  device they want to access.
676
677	  If you don't require the option or are in doubt, say N.
678
679config X86_RDC321X
680	bool "RDC R-321x SoC"
681	depends on X86_32
682	depends on X86_EXTENDED_PLATFORM
683	select M486
684	select X86_REBOOTFIXUPS
685	help
686	  This option is needed for RDC R-321x system-on-chip, also known
687	  as R-8610-(G).
688	  If you don't have one of these chips, you should say N here.
689
690config X86_32_NON_STANDARD
691	bool "Support non-standard 32-bit SMP architectures"
692	depends on X86_32 && SMP
693	depends on X86_EXTENDED_PLATFORM
694	help
695	  This option compiles in the bigsmp and STA2X11 default
696	  subarchitectures.  It is intended for a generic binary
697	  kernel. If you select them all, kernel will probe it one by
698	  one and will fallback to default.
699
700# Alphabetically sorted list of Non standard 32 bit platforms
701
702config X86_SUPPORTS_MEMORY_FAILURE
703	def_bool y
704	# MCE code calls memory_failure():
705	depends on X86_MCE
706	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
707	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
708	depends on X86_64 || !SPARSEMEM
709	select ARCH_SUPPORTS_MEMORY_FAILURE
710
711config STA2X11
712	bool "STA2X11 Companion Chip Support"
713	depends on X86_32_NON_STANDARD && PCI
714	select SWIOTLB
715	select MFD_STA2X11
716	select GPIOLIB
717	help
718	  This adds support for boards based on the STA2X11 IO-Hub,
719	  a.k.a. "ConneXt". The chip is used in place of the standard
720	  PC chipset, so all "standard" peripherals are missing. If this
721	  option is selected the kernel will still be able to boot on
722	  standard PC machines.
723
724config X86_32_IRIS
725	tristate "Eurobraille/Iris poweroff module"
726	depends on X86_32
727	help
728	  The Iris machines from EuroBraille do not have APM or ACPI support
729	  to shut themselves down properly.  A special I/O sequence is
730	  needed to do so, which is what this module does at
731	  kernel shutdown.
732
733	  This is only for Iris machines from EuroBraille.
734
735	  If unused, say N.
736
737config SCHED_OMIT_FRAME_POINTER
738	def_bool y
739	prompt "Single-depth WCHAN output"
740	depends on X86
741	help
742	  Calculate simpler /proc/<PID>/wchan values. If this option
743	  is disabled then wchan values will recurse back to the
744	  caller function. This provides more accurate wchan values,
745	  at the expense of slightly more scheduling overhead.
746
747	  If in doubt, say "Y".
748
749menuconfig HYPERVISOR_GUEST
750	bool "Linux guest support"
751	help
752	  Say Y here to enable options for running Linux under various hyper-
753	  visors. This option enables basic hypervisor detection and platform
754	  setup.
755
756	  If you say N, all options in this submenu will be skipped and
757	  disabled, and Linux guest support won't be built in.
758
759if HYPERVISOR_GUEST
760
761config PARAVIRT
762	bool "Enable paravirtualization code"
763	help
764	  This changes the kernel so it can modify itself when it is run
765	  under a hypervisor, potentially improving performance significantly
766	  over full virtualization.  However, when run without a hypervisor
767	  the kernel is theoretically slower and slightly larger.
768
769config PARAVIRT_XXL
770	bool
771
772config PARAVIRT_DEBUG
773	bool "paravirt-ops debugging"
774	depends on PARAVIRT && DEBUG_KERNEL
775	help
776	  Enable to debug paravirt_ops internals.  Specifically, BUG if
777	  a paravirt_op is missing when it is called.
778
779config PARAVIRT_SPINLOCKS
780	bool "Paravirtualization layer for spinlocks"
781	depends on PARAVIRT && SMP
782	help
783	  Paravirtualized spinlocks allow a pvops backend to replace the
784	  spinlock implementation with something virtualization-friendly
785	  (for example, block the virtual CPU rather than spinning).
786
787	  It has a minimal impact on native kernels and gives a nice performance
788	  benefit on paravirtualized KVM / Xen kernels.
789
790	  If you are unsure how to answer this question, answer Y.
791
792config X86_HV_CALLBACK_VECTOR
793	def_bool n
794
795source "arch/x86/xen/Kconfig"
796
797config KVM_GUEST
798	bool "KVM Guest support (including kvmclock)"
799	depends on PARAVIRT
800	select PARAVIRT_CLOCK
801	select ARCH_CPUIDLE_HALTPOLL
802	select X86_HV_CALLBACK_VECTOR
803	default y
804	help
805	  This option enables various optimizations for running under the KVM
806	  hypervisor. It includes a paravirtualized clock, so that instead
807	  of relying on a PIT (or probably other) emulation by the
808	  underlying device model, the host provides the guest with
809	  timing infrastructure such as time of day, and system time
810
811config ARCH_CPUIDLE_HALTPOLL
812	def_bool n
813	prompt "Disable host haltpoll when loading haltpoll driver"
814	help
815	  If virtualized under KVM, disable host haltpoll.
816
817config PVH
818	bool "Support for running PVH guests"
819	help
820	  This option enables the PVH entry point for guest virtual machines
821	  as specified in the x86/HVM direct boot ABI.
822
823config PARAVIRT_TIME_ACCOUNTING
824	bool "Paravirtual steal time accounting"
825	depends on PARAVIRT
826	help
827	  Select this option to enable fine granularity task steal time
828	  accounting. Time spent executing other tasks in parallel with
829	  the current vCPU is discounted from the vCPU power. To account for
830	  that, there can be a small performance impact.
831
832	  If in doubt, say N here.
833
834config PARAVIRT_CLOCK
835	bool
836
837config JAILHOUSE_GUEST
838	bool "Jailhouse non-root cell support"
839	depends on X86_64 && PCI
840	select X86_PM_TIMER
841	help
842	  This option allows to run Linux as guest in a Jailhouse non-root
843	  cell. You can leave this option disabled if you only want to start
844	  Jailhouse and run Linux afterwards in the root cell.
845
846config ACRN_GUEST
847	bool "ACRN Guest support"
848	depends on X86_64
849	select X86_HV_CALLBACK_VECTOR
850	help
851	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
852	  a flexible, lightweight reference open-source hypervisor, built with
853	  real-time and safety-criticality in mind. It is built for embedded
854	  IOT with small footprint and real-time features. More details can be
855	  found in https://projectacrn.org/.
856
857endif #HYPERVISOR_GUEST
858
859source "arch/x86/Kconfig.cpu"
860
861config HPET_TIMER
862	def_bool X86_64
863	prompt "HPET Timer Support" if X86_32
864	help
865	  Use the IA-PC HPET (High Precision Event Timer) to manage
866	  time in preference to the PIT and RTC, if a HPET is
867	  present.
868	  HPET is the next generation timer replacing legacy 8254s.
869	  The HPET provides a stable time base on SMP
870	  systems, unlike the TSC, but it is more expensive to access,
871	  as it is off-chip.  The interface used is documented
872	  in the HPET spec, revision 1.
873
874	  You can safely choose Y here.  However, HPET will only be
875	  activated if the platform and the BIOS support this feature.
876	  Otherwise the 8254 will be used for timing services.
877
878	  Choose N to continue using the legacy 8254 timer.
879
880config HPET_EMULATE_RTC
881	def_bool y
882	depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
883
884config APB_TIMER
885	def_bool y if X86_INTEL_MID
886	prompt "Intel MID APB Timer Support" if X86_INTEL_MID
887	select DW_APB_TIMER
888	depends on X86_INTEL_MID && SFI
889	help
890	 APB timer is the replacement for 8254, HPET on X86 MID platforms.
891	 The APBT provides a stable time base on SMP
892	 systems, unlike the TSC, but it is more expensive to access,
893	 as it is off-chip. APB timers are always running regardless of CPU
894	 C states, they are used as per CPU clockevent device when possible.
895
896# Mark as expert because too many people got it wrong.
897# The code disables itself when not needed.
898config DMI
899	default y
900	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
901	bool "Enable DMI scanning" if EXPERT
902	help
903	  Enabled scanning of DMI to identify machine quirks. Say Y
904	  here unless you have verified that your setup is not
905	  affected by entries in the DMI blacklist. Required by PNP
906	  BIOS code.
907
908config GART_IOMMU
909	bool "Old AMD GART IOMMU support"
910	select DMA_OPS
911	select IOMMU_HELPER
912	select SWIOTLB
913	depends on X86_64 && PCI && AMD_NB
914	help
915	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
916	  GART based hardware IOMMUs.
917
918	  The GART supports full DMA access for devices with 32-bit access
919	  limitations, on systems with more than 3 GB. This is usually needed
920	  for USB, sound, many IDE/SATA chipsets and some other devices.
921
922	  Newer systems typically have a modern AMD IOMMU, supported via
923	  the CONFIG_AMD_IOMMU=y config option.
924
925	  In normal configurations this driver is only active when needed:
926	  there's more than 3 GB of memory and the system contains a
927	  32-bit limited device.
928
929	  If unsure, say Y.
930
931config MAXSMP
932	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
933	depends on X86_64 && SMP && DEBUG_KERNEL
934	select CPUMASK_OFFSTACK
935	help
936	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
937	  If unsure, say N.
938
939#
940# The maximum number of CPUs supported:
941#
942# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
943# and which can be configured interactively in the
944# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
945#
946# The ranges are different on 32-bit and 64-bit kernels, depending on
947# hardware capabilities and scalability features of the kernel.
948#
949# ( If MAXSMP is enabled we just use the highest possible value and disable
950#   interactive configuration. )
951#
952
953config NR_CPUS_RANGE_BEGIN
954	int
955	default NR_CPUS_RANGE_END if MAXSMP
956	default    1 if !SMP
957	default    2
958
959config NR_CPUS_RANGE_END
960	int
961	depends on X86_32
962	default   64 if  SMP &&  X86_BIGSMP
963	default    8 if  SMP && !X86_BIGSMP
964	default    1 if !SMP
965
966config NR_CPUS_RANGE_END
967	int
968	depends on X86_64
969	default 8192 if  SMP && CPUMASK_OFFSTACK
970	default  512 if  SMP && !CPUMASK_OFFSTACK
971	default    1 if !SMP
972
973config NR_CPUS_DEFAULT
974	int
975	depends on X86_32
976	default   32 if  X86_BIGSMP
977	default    8 if  SMP
978	default    1 if !SMP
979
980config NR_CPUS_DEFAULT
981	int
982	depends on X86_64
983	default 8192 if  MAXSMP
984	default   64 if  SMP
985	default    1 if !SMP
986
987config NR_CPUS
988	int "Maximum number of CPUs" if SMP && !MAXSMP
989	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
990	default NR_CPUS_DEFAULT
991	help
992	  This allows you to specify the maximum number of CPUs which this
993	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
994	  supported value is 8192, otherwise the maximum value is 512.  The
995	  minimum value which makes sense is 2.
996
997	  This is purely to save memory: each supported CPU adds about 8KB
998	  to the kernel image.
999
1000config SCHED_SMT
1001	def_bool y if SMP
1002
1003config SCHED_MC
1004	def_bool y
1005	prompt "Multi-core scheduler support"
1006	depends on SMP
1007	help
1008	  Multi-core scheduler support improves the CPU scheduler's decision
1009	  making when dealing with multi-core CPU chips at a cost of slightly
1010	  increased overhead in some places. If unsure say N here.
1011
1012config SCHED_MC_PRIO
1013	bool "CPU core priorities scheduler support"
1014	depends on SCHED_MC && CPU_SUP_INTEL
1015	select X86_INTEL_PSTATE
1016	select CPU_FREQ
1017	default y
1018	help
1019	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1020	  core ordering determined at manufacturing time, which allows
1021	  certain cores to reach higher turbo frequencies (when running
1022	  single threaded workloads) than others.
1023
1024	  Enabling this kernel feature teaches the scheduler about
1025	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1026	  scheduler's CPU selection logic accordingly, so that higher
1027	  overall system performance can be achieved.
1028
1029	  This feature will have no effect on CPUs without this feature.
1030
1031	  If unsure say Y here.
1032
1033config UP_LATE_INIT
1034	def_bool y
1035	depends on !SMP && X86_LOCAL_APIC
1036
1037config X86_UP_APIC
1038	bool "Local APIC support on uniprocessors" if !PCI_MSI
1039	default PCI_MSI
1040	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1041	help
1042	  A local APIC (Advanced Programmable Interrupt Controller) is an
1043	  integrated interrupt controller in the CPU. If you have a single-CPU
1044	  system which has a processor with a local APIC, you can say Y here to
1045	  enable and use it. If you say Y here even though your machine doesn't
1046	  have a local APIC, then the kernel will still run with no slowdown at
1047	  all. The local APIC supports CPU-generated self-interrupts (timer,
1048	  performance counters), and the NMI watchdog which detects hard
1049	  lockups.
1050
1051config X86_UP_IOAPIC
1052	bool "IO-APIC support on uniprocessors"
1053	depends on X86_UP_APIC
1054	help
1055	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1056	  SMP-capable replacement for PC-style interrupt controllers. Most
1057	  SMP systems and many recent uniprocessor systems have one.
1058
1059	  If you have a single-CPU system with an IO-APIC, you can say Y here
1060	  to use it. If you say Y here even though your machine doesn't have
1061	  an IO-APIC, then the kernel will still run with no slowdown at all.
1062
1063config X86_LOCAL_APIC
1064	def_bool y
1065	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1066	select IRQ_DOMAIN_HIERARCHY
1067	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1068
1069config X86_IO_APIC
1070	def_bool y
1071	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1072
1073config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1074	bool "Reroute for broken boot IRQs"
1075	depends on X86_IO_APIC
1076	help
1077	  This option enables a workaround that fixes a source of
1078	  spurious interrupts. This is recommended when threaded
1079	  interrupt handling is used on systems where the generation of
1080	  superfluous "boot interrupts" cannot be disabled.
1081
1082	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1083	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1084	  kernel does during interrupt handling). On chipsets where this
1085	  boot IRQ generation cannot be disabled, this workaround keeps
1086	  the original IRQ line masked so that only the equivalent "boot
1087	  IRQ" is delivered to the CPUs. The workaround also tells the
1088	  kernel to set up the IRQ handler on the boot IRQ line. In this
1089	  way only one interrupt is delivered to the kernel. Otherwise
1090	  the spurious second interrupt may cause the kernel to bring
1091	  down (vital) interrupt lines.
1092
1093	  Only affects "broken" chipsets. Interrupt sharing may be
1094	  increased on these systems.
1095
1096config X86_MCE
1097	bool "Machine Check / overheating reporting"
1098	select GENERIC_ALLOCATOR
1099	default y
1100	help
1101	  Machine Check support allows the processor to notify the
1102	  kernel if it detects a problem (e.g. overheating, data corruption).
1103	  The action the kernel takes depends on the severity of the problem,
1104	  ranging from warning messages to halting the machine.
1105
1106config X86_MCELOG_LEGACY
1107	bool "Support for deprecated /dev/mcelog character device"
1108	depends on X86_MCE
1109	help
1110	  Enable support for /dev/mcelog which is needed by the old mcelog
1111	  userspace logging daemon. Consider switching to the new generation
1112	  rasdaemon solution.
1113
1114config X86_MCE_INTEL
1115	def_bool y
1116	prompt "Intel MCE features"
1117	depends on X86_MCE && X86_LOCAL_APIC
1118	help
1119	   Additional support for intel specific MCE features such as
1120	   the thermal monitor.
1121
1122config X86_MCE_AMD
1123	def_bool y
1124	prompt "AMD MCE features"
1125	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1126	help
1127	   Additional support for AMD specific MCE features such as
1128	   the DRAM Error Threshold.
1129
1130config X86_ANCIENT_MCE
1131	bool "Support for old Pentium 5 / WinChip machine checks"
1132	depends on X86_32 && X86_MCE
1133	help
1134	  Include support for machine check handling on old Pentium 5 or WinChip
1135	  systems. These typically need to be enabled explicitly on the command
1136	  line.
1137
1138config X86_MCE_THRESHOLD
1139	depends on X86_MCE_AMD || X86_MCE_INTEL
1140	def_bool y
1141
1142config X86_MCE_INJECT
1143	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1144	tristate "Machine check injector support"
1145	help
1146	  Provide support for injecting machine checks for testing purposes.
1147	  If you don't know what a machine check is and you don't do kernel
1148	  QA it is safe to say n.
1149
1150config X86_THERMAL_VECTOR
1151	def_bool y
1152	depends on X86_MCE_INTEL
1153
1154source "arch/x86/events/Kconfig"
1155
1156config X86_LEGACY_VM86
1157	bool "Legacy VM86 support"
1158	depends on X86_32
1159	help
1160	  This option allows user programs to put the CPU into V8086
1161	  mode, which is an 80286-era approximation of 16-bit real mode.
1162
1163	  Some very old versions of X and/or vbetool require this option
1164	  for user mode setting.  Similarly, DOSEMU will use it if
1165	  available to accelerate real mode DOS programs.  However, any
1166	  recent version of DOSEMU, X, or vbetool should be fully
1167	  functional even without kernel VM86 support, as they will all
1168	  fall back to software emulation. Nevertheless, if you are using
1169	  a 16-bit DOS program where 16-bit performance matters, vm86
1170	  mode might be faster than emulation and you might want to
1171	  enable this option.
1172
1173	  Note that any app that works on a 64-bit kernel is unlikely to
1174	  need this option, as 64-bit kernels don't, and can't, support
1175	  V8086 mode. This option is also unrelated to 16-bit protected
1176	  mode and is not needed to run most 16-bit programs under Wine.
1177
1178	  Enabling this option increases the complexity of the kernel
1179	  and slows down exception handling a tiny bit.
1180
1181	  If unsure, say N here.
1182
1183config VM86
1184	bool
1185	default X86_LEGACY_VM86
1186
1187config X86_16BIT
1188	bool "Enable support for 16-bit segments" if EXPERT
1189	default y
1190	depends on MODIFY_LDT_SYSCALL
1191	help
1192	  This option is required by programs like Wine to run 16-bit
1193	  protected mode legacy code on x86 processors.  Disabling
1194	  this option saves about 300 bytes on i386, or around 6K text
1195	  plus 16K runtime memory on x86-64,
1196
1197config X86_ESPFIX32
1198	def_bool y
1199	depends on X86_16BIT && X86_32
1200
1201config X86_ESPFIX64
1202	def_bool y
1203	depends on X86_16BIT && X86_64
1204
1205config X86_VSYSCALL_EMULATION
1206	bool "Enable vsyscall emulation" if EXPERT
1207	default y
1208	depends on X86_64
1209	help
1210	 This enables emulation of the legacy vsyscall page.  Disabling
1211	 it is roughly equivalent to booting with vsyscall=none, except
1212	 that it will also disable the helpful warning if a program
1213	 tries to use a vsyscall.  With this option set to N, offending
1214	 programs will just segfault, citing addresses of the form
1215	 0xffffffffff600?00.
1216
1217	 This option is required by many programs built before 2013, and
1218	 care should be used even with newer programs if set to N.
1219
1220	 Disabling this option saves about 7K of kernel size and
1221	 possibly 4K of additional runtime pagetable memory.
1222
1223config X86_IOPL_IOPERM
1224	bool "IOPERM and IOPL Emulation"
1225	default y
1226	help
1227	  This enables the ioperm() and iopl() syscalls which are necessary
1228	  for legacy applications.
1229
1230	  Legacy IOPL support is an overbroad mechanism which allows user
1231	  space aside of accessing all 65536 I/O ports also to disable
1232	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1233	  capabilities and permission from potentially active security
1234	  modules.
1235
1236	  The emulation restricts the functionality of the syscall to
1237	  only allowing the full range I/O port access, but prevents the
1238	  ability to disable interrupts from user space which would be
1239	  granted if the hardware IOPL mechanism would be used.
1240
1241config TOSHIBA
1242	tristate "Toshiba Laptop support"
1243	depends on X86_32
1244	help
1245	  This adds a driver to safely access the System Management Mode of
1246	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1247	  not work on models with a Phoenix BIOS. The System Management Mode
1248	  is used to set the BIOS and power saving options on Toshiba portables.
1249
1250	  For information on utilities to make use of this driver see the
1251	  Toshiba Linux utilities web site at:
1252	  <http://www.buzzard.org.uk/toshiba/>.
1253
1254	  Say Y if you intend to run this kernel on a Toshiba portable.
1255	  Say N otherwise.
1256
1257config I8K
1258	tristate "Dell i8k legacy laptop support"
1259	depends on HWMON
1260	depends on PROC_FS
1261	select SENSORS_DELL_SMM
1262	help
1263	  This option enables legacy /proc/i8k userspace interface in hwmon
1264	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1265	  temperature and allows controlling fan speeds of Dell laptops via
1266	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1267	  it reports also power and hotkey status. For fan speed control is
1268	  needed userspace package i8kutils.
1269
1270	  Say Y if you intend to run this kernel on old Dell laptops or want to
1271	  use userspace package i8kutils.
1272	  Say N otherwise.
1273
1274config X86_REBOOTFIXUPS
1275	bool "Enable X86 board specific fixups for reboot"
1276	depends on X86_32
1277	help
1278	  This enables chipset and/or board specific fixups to be done
1279	  in order to get reboot to work correctly. This is only needed on
1280	  some combinations of hardware and BIOS. The symptom, for which
1281	  this config is intended, is when reboot ends with a stalled/hung
1282	  system.
1283
1284	  Currently, the only fixup is for the Geode machines using
1285	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1286
1287	  Say Y if you want to enable the fixup. Currently, it's safe to
1288	  enable this option even if you don't need it.
1289	  Say N otherwise.
1290
1291config MICROCODE
1292	bool "CPU microcode loading support"
1293	default y
1294	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1295	help
1296	  If you say Y here, you will be able to update the microcode on
1297	  Intel and AMD processors. The Intel support is for the IA32 family,
1298	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1299	  AMD support is for families 0x10 and later. You will obviously need
1300	  the actual microcode binary data itself which is not shipped with
1301	  the Linux kernel.
1302
1303	  The preferred method to load microcode from a detached initrd is described
1304	  in Documentation/x86/microcode.rst. For that you need to enable
1305	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1306	  initrd for microcode blobs.
1307
1308	  In addition, you can build the microcode into the kernel. For that you
1309	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1310	  config option.
1311
1312config MICROCODE_INTEL
1313	bool "Intel microcode loading support"
1314	depends on CPU_SUP_INTEL && MICROCODE
1315	default MICROCODE
1316	help
1317	  This options enables microcode patch loading support for Intel
1318	  processors.
1319
1320	  For the current Intel microcode data package go to
1321	  <https://downloadcenter.intel.com> and search for
1322	  'Linux Processor Microcode Data File'.
1323
1324config MICROCODE_AMD
1325	bool "AMD microcode loading support"
1326	depends on CPU_SUP_AMD && MICROCODE
1327	help
1328	  If you select this option, microcode patch loading support for AMD
1329	  processors will be enabled.
1330
1331config MICROCODE_LATE_LOADING
1332	bool "Late microcode loading (DANGEROUS)"
1333	default n
1334	depends on MICROCODE
1335	help
1336	  Loading microcode late, when the system is up and executing instructions
1337	  is a tricky business and should be avoided if possible. Just the sequence
1338	  of synchronizing all cores and SMT threads is one fragile dance which does
1339	  not guarantee that cores might not softlock after the loading. Therefore,
1340	  use this at your own risk. Late loading taints the kernel too.
1341
1342config X86_MSR
1343	tristate "/dev/cpu/*/msr - Model-specific register support"
1344	help
1345	  This device gives privileged processes access to the x86
1346	  Model-Specific Registers (MSRs).  It is a character device with
1347	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1348	  MSR accesses are directed to a specific CPU on multi-processor
1349	  systems.
1350
1351config X86_CPUID
1352	tristate "/dev/cpu/*/cpuid - CPU information support"
1353	help
1354	  This device gives processes access to the x86 CPUID instruction to
1355	  be executed on a specific processor.  It is a character device
1356	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1357	  /dev/cpu/31/cpuid.
1358
1359choice
1360	prompt "High Memory Support"
1361	default HIGHMEM4G
1362	depends on X86_32
1363
1364config NOHIGHMEM
1365	bool "off"
1366	help
1367	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1368	  However, the address space of 32-bit x86 processors is only 4
1369	  Gigabytes large. That means that, if you have a large amount of
1370	  physical memory, not all of it can be "permanently mapped" by the
1371	  kernel. The physical memory that's not permanently mapped is called
1372	  "high memory".
1373
1374	  If you are compiling a kernel which will never run on a machine with
1375	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1376	  choice and suitable for most users). This will result in a "3GB/1GB"
1377	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1378	  space and the remaining part of the 4GB virtual memory space is used
1379	  by the kernel to permanently map as much physical memory as
1380	  possible.
1381
1382	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1383	  answer "4GB" here.
1384
1385	  If more than 4 Gigabytes is used then answer "64GB" here. This
1386	  selection turns Intel PAE (Physical Address Extension) mode on.
1387	  PAE implements 3-level paging on IA32 processors. PAE is fully
1388	  supported by Linux, PAE mode is implemented on all recent Intel
1389	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1390	  then the kernel will not boot on CPUs that don't support PAE!
1391
1392	  The actual amount of total physical memory will either be
1393	  auto detected or can be forced by using a kernel command line option
1394	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1395	  your boot loader (lilo or loadlin) about how to pass options to the
1396	  kernel at boot time.)
1397
1398	  If unsure, say "off".
1399
1400config HIGHMEM4G
1401	bool "4GB"
1402	help
1403	  Select this if you have a 32-bit processor and between 1 and 4
1404	  gigabytes of physical RAM.
1405
1406config HIGHMEM64G
1407	bool "64GB"
1408	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1409	select X86_PAE
1410	help
1411	  Select this if you have a 32-bit processor and more than 4
1412	  gigabytes of physical RAM.
1413
1414endchoice
1415
1416choice
1417	prompt "Memory split" if EXPERT
1418	default VMSPLIT_3G
1419	depends on X86_32
1420	help
1421	  Select the desired split between kernel and user memory.
1422
1423	  If the address range available to the kernel is less than the
1424	  physical memory installed, the remaining memory will be available
1425	  as "high memory". Accessing high memory is a little more costly
1426	  than low memory, as it needs to be mapped into the kernel first.
1427	  Note that increasing the kernel address space limits the range
1428	  available to user programs, making the address space there
1429	  tighter.  Selecting anything other than the default 3G/1G split
1430	  will also likely make your kernel incompatible with binary-only
1431	  kernel modules.
1432
1433	  If you are not absolutely sure what you are doing, leave this
1434	  option alone!
1435
1436	config VMSPLIT_3G
1437		bool "3G/1G user/kernel split"
1438	config VMSPLIT_3G_OPT
1439		depends on !X86_PAE
1440		bool "3G/1G user/kernel split (for full 1G low memory)"
1441	config VMSPLIT_2G
1442		bool "2G/2G user/kernel split"
1443	config VMSPLIT_2G_OPT
1444		depends on !X86_PAE
1445		bool "2G/2G user/kernel split (for full 2G low memory)"
1446	config VMSPLIT_1G
1447		bool "1G/3G user/kernel split"
1448endchoice
1449
1450config PAGE_OFFSET
1451	hex
1452	default 0xB0000000 if VMSPLIT_3G_OPT
1453	default 0x80000000 if VMSPLIT_2G
1454	default 0x78000000 if VMSPLIT_2G_OPT
1455	default 0x40000000 if VMSPLIT_1G
1456	default 0xC0000000
1457	depends on X86_32
1458
1459config HIGHMEM
1460	def_bool y
1461	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1462
1463config X86_PAE
1464	bool "PAE (Physical Address Extension) Support"
1465	depends on X86_32 && !HIGHMEM4G
1466	select PHYS_ADDR_T_64BIT
1467	select SWIOTLB
1468	help
1469	  PAE is required for NX support, and furthermore enables
1470	  larger swapspace support for non-overcommit purposes. It
1471	  has the cost of more pagetable lookup overhead, and also
1472	  consumes more pagetable space per process.
1473
1474config X86_5LEVEL
1475	bool "Enable 5-level page tables support"
1476	default y
1477	select DYNAMIC_MEMORY_LAYOUT
1478	select SPARSEMEM_VMEMMAP
1479	depends on X86_64
1480	help
1481	  5-level paging enables access to larger address space:
1482	  upto 128 PiB of virtual address space and 4 PiB of
1483	  physical address space.
1484
1485	  It will be supported by future Intel CPUs.
1486
1487	  A kernel with the option enabled can be booted on machines that
1488	  support 4- or 5-level paging.
1489
1490	  See Documentation/x86/x86_64/5level-paging.rst for more
1491	  information.
1492
1493	  Say N if unsure.
1494
1495config X86_DIRECT_GBPAGES
1496	def_bool y
1497	depends on X86_64
1498	help
1499	  Certain kernel features effectively disable kernel
1500	  linear 1 GB mappings (even if the CPU otherwise
1501	  supports them), so don't confuse the user by printing
1502	  that we have them enabled.
1503
1504config X86_CPA_STATISTICS
1505	bool "Enable statistic for Change Page Attribute"
1506	depends on DEBUG_FS
1507	help
1508	  Expose statistics about the Change Page Attribute mechanism, which
1509	  helps to determine the effectiveness of preserving large and huge
1510	  page mappings when mapping protections are changed.
1511
1512config AMD_MEM_ENCRYPT
1513	bool "AMD Secure Memory Encryption (SME) support"
1514	depends on X86_64 && CPU_SUP_AMD
1515	select DMA_COHERENT_POOL
1516	select DYNAMIC_PHYSICAL_MASK
1517	select ARCH_USE_MEMREMAP_PROT
1518	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1519	select INSTRUCTION_DECODER
1520	select ARCH_HAS_CC_PLATFORM
1521	help
1522	  Say yes to enable support for the encryption of system memory.
1523	  This requires an AMD processor that supports Secure Memory
1524	  Encryption (SME).
1525
1526config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1527	bool "Activate AMD Secure Memory Encryption (SME) by default"
1528	depends on AMD_MEM_ENCRYPT
1529	help
1530	  Say yes to have system memory encrypted by default if running on
1531	  an AMD processor that supports Secure Memory Encryption (SME).
1532
1533	  If set to Y, then the encryption of system memory can be
1534	  deactivated with the mem_encrypt=off command line option.
1535
1536	  If set to N, then the encryption of system memory can be
1537	  activated with the mem_encrypt=on command line option.
1538
1539# Common NUMA Features
1540config NUMA
1541	bool "NUMA Memory Allocation and Scheduler Support"
1542	depends on SMP
1543	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1544	default y if X86_BIGSMP
1545	help
1546	  Enable NUMA (Non-Uniform Memory Access) support.
1547
1548	  The kernel will try to allocate memory used by a CPU on the
1549	  local memory controller of the CPU and add some more
1550	  NUMA awareness to the kernel.
1551
1552	  For 64-bit this is recommended if the system is Intel Core i7
1553	  (or later), AMD Opteron, or EM64T NUMA.
1554
1555	  For 32-bit this is only needed if you boot a 32-bit
1556	  kernel on a 64-bit NUMA platform.
1557
1558	  Otherwise, you should say N.
1559
1560config AMD_NUMA
1561	def_bool y
1562	prompt "Old style AMD Opteron NUMA detection"
1563	depends on X86_64 && NUMA && PCI
1564	help
1565	  Enable AMD NUMA node topology detection.  You should say Y here if
1566	  you have a multi processor AMD system. This uses an old method to
1567	  read the NUMA configuration directly from the builtin Northbridge
1568	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1569	  which also takes priority if both are compiled in.
1570
1571config X86_64_ACPI_NUMA
1572	def_bool y
1573	prompt "ACPI NUMA detection"
1574	depends on X86_64 && NUMA && ACPI && PCI
1575	select ACPI_NUMA
1576	help
1577	  Enable ACPI SRAT based node topology detection.
1578
1579config NUMA_EMU
1580	bool "NUMA emulation"
1581	depends on NUMA
1582	help
1583	  Enable NUMA emulation. A flat machine will be split
1584	  into virtual nodes when booted with "numa=fake=N", where N is the
1585	  number of nodes. This is only useful for debugging.
1586
1587config NODES_SHIFT
1588	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1589	range 1 10
1590	default "10" if MAXSMP
1591	default "6" if X86_64
1592	default "3"
1593	depends on NEED_MULTIPLE_NODES
1594	help
1595	  Specify the maximum number of NUMA Nodes available on the target
1596	  system.  Increases memory reserved to accommodate various tables.
1597
1598config ARCH_FLATMEM_ENABLE
1599	def_bool y
1600	depends on X86_32 && !NUMA
1601
1602config ARCH_SPARSEMEM_ENABLE
1603	def_bool y
1604	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1605	select SPARSEMEM_STATIC if X86_32
1606	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1607
1608config ARCH_SPARSEMEM_DEFAULT
1609	def_bool X86_64 || (NUMA && X86_32)
1610
1611config ARCH_SELECT_MEMORY_MODEL
1612	def_bool y
1613	depends on ARCH_SPARSEMEM_ENABLE
1614
1615config ARCH_MEMORY_PROBE
1616	bool "Enable sysfs memory/probe interface"
1617	depends on X86_64 && MEMORY_HOTPLUG
1618	help
1619	  This option enables a sysfs memory/probe interface for testing.
1620	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1621	  If you are unsure how to answer this question, answer N.
1622
1623config ARCH_PROC_KCORE_TEXT
1624	def_bool y
1625	depends on X86_64 && PROC_KCORE
1626
1627config ILLEGAL_POINTER_VALUE
1628	hex
1629	default 0 if X86_32
1630	default 0xdead000000000000 if X86_64
1631
1632config X86_PMEM_LEGACY_DEVICE
1633	bool
1634
1635config X86_PMEM_LEGACY
1636	tristate "Support non-standard NVDIMMs and ADR protected memory"
1637	depends on PHYS_ADDR_T_64BIT
1638	depends on BLK_DEV
1639	select X86_PMEM_LEGACY_DEVICE
1640	select NUMA_KEEP_MEMINFO if NUMA
1641	select LIBNVDIMM
1642	help
1643	  Treat memory marked using the non-standard e820 type of 12 as used
1644	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1645	  The kernel will offer these regions to the 'pmem' driver so
1646	  they can be used for persistent storage.
1647
1648	  Say Y if unsure.
1649
1650config HIGHPTE
1651	bool "Allocate 3rd-level pagetables from highmem"
1652	depends on HIGHMEM
1653	help
1654	  The VM uses one page table entry for each page of physical memory.
1655	  For systems with a lot of RAM, this can be wasteful of precious
1656	  low memory.  Setting this option will put user-space page table
1657	  entries in high memory.
1658
1659config X86_CHECK_BIOS_CORRUPTION
1660	bool "Check for low memory corruption"
1661	help
1662	  Periodically check for memory corruption in low memory, which
1663	  is suspected to be caused by BIOS.  Even when enabled in the
1664	  configuration, it is disabled at runtime.  Enable it by
1665	  setting "memory_corruption_check=1" on the kernel command
1666	  line.  By default it scans the low 64k of memory every 60
1667	  seconds; see the memory_corruption_check_size and
1668	  memory_corruption_check_period parameters in
1669	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1670
1671	  When enabled with the default parameters, this option has
1672	  almost no overhead, as it reserves a relatively small amount
1673	  of memory and scans it infrequently.  It both detects corruption
1674	  and prevents it from affecting the running system.
1675
1676	  It is, however, intended as a diagnostic tool; if repeatable
1677	  BIOS-originated corruption always affects the same memory,
1678	  you can use memmap= to prevent the kernel from using that
1679	  memory.
1680
1681config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1682	bool "Set the default setting of memory_corruption_check"
1683	depends on X86_CHECK_BIOS_CORRUPTION
1684	default y
1685	help
1686	  Set whether the default state of memory_corruption_check is
1687	  on or off.
1688
1689config X86_RESERVE_LOW
1690	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1691	default 64
1692	range 4 640
1693	help
1694	  Specify the amount of low memory to reserve for the BIOS.
1695
1696	  The first page contains BIOS data structures that the kernel
1697	  must not use, so that page must always be reserved.
1698
1699	  By default we reserve the first 64K of physical RAM, as a
1700	  number of BIOSes are known to corrupt that memory range
1701	  during events such as suspend/resume or monitor cable
1702	  insertion, so it must not be used by the kernel.
1703
1704	  You can set this to 4 if you are absolutely sure that you
1705	  trust the BIOS to get all its memory reservations and usages
1706	  right.  If you know your BIOS have problems beyond the
1707	  default 64K area, you can set this to 640 to avoid using the
1708	  entire low memory range.
1709
1710	  If you have doubts about the BIOS (e.g. suspend/resume does
1711	  not work or there's kernel crashes after certain hardware
1712	  hotplug events) then you might want to enable
1713	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1714	  typical corruption patterns.
1715
1716	  Leave this to the default value of 64 if you are unsure.
1717
1718config MATH_EMULATION
1719	bool
1720	depends on MODIFY_LDT_SYSCALL
1721	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1722	help
1723	  Linux can emulate a math coprocessor (used for floating point
1724	  operations) if you don't have one. 486DX and Pentium processors have
1725	  a math coprocessor built in, 486SX and 386 do not, unless you added
1726	  a 487DX or 387, respectively. (The messages during boot time can
1727	  give you some hints here ["man dmesg"].) Everyone needs either a
1728	  coprocessor or this emulation.
1729
1730	  If you don't have a math coprocessor, you need to say Y here; if you
1731	  say Y here even though you have a coprocessor, the coprocessor will
1732	  be used nevertheless. (This behavior can be changed with the kernel
1733	  command line option "no387", which comes handy if your coprocessor
1734	  is broken. Try "man bootparam" or see the documentation of your boot
1735	  loader (lilo or loadlin) about how to pass options to the kernel at
1736	  boot time.) This means that it is a good idea to say Y here if you
1737	  intend to use this kernel on different machines.
1738
1739	  More information about the internals of the Linux math coprocessor
1740	  emulation can be found in <file:arch/x86/math-emu/README>.
1741
1742	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1743	  kernel, it won't hurt.
1744
1745config MTRR
1746	def_bool y
1747	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1748	help
1749	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1750	  the Memory Type Range Registers (MTRRs) may be used to control
1751	  processor access to memory ranges. This is most useful if you have
1752	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1753	  allows bus write transfers to be combined into a larger transfer
1754	  before bursting over the PCI/AGP bus. This can increase performance
1755	  of image write operations 2.5 times or more. Saying Y here creates a
1756	  /proc/mtrr file which may be used to manipulate your processor's
1757	  MTRRs. Typically the X server should use this.
1758
1759	  This code has a reasonably generic interface so that similar
1760	  control registers on other processors can be easily supported
1761	  as well:
1762
1763	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1764	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1765	  these, the ARRs are used to emulate the MTRRs.
1766	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1767	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1768	  write-combining. All of these processors are supported by this code
1769	  and it makes sense to say Y here if you have one of them.
1770
1771	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1772	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1773	  can lead to all sorts of problems, so it's good to say Y here.
1774
1775	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1776	  just add about 9 KB to your kernel.
1777
1778	  See <file:Documentation/x86/mtrr.rst> for more information.
1779
1780config MTRR_SANITIZER
1781	def_bool y
1782	prompt "MTRR cleanup support"
1783	depends on MTRR
1784	help
1785	  Convert MTRR layout from continuous to discrete, so X drivers can
1786	  add writeback entries.
1787
1788	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1789	  The largest mtrr entry size for a continuous block can be set with
1790	  mtrr_chunk_size.
1791
1792	  If unsure, say Y.
1793
1794config MTRR_SANITIZER_ENABLE_DEFAULT
1795	int "MTRR cleanup enable value (0-1)"
1796	range 0 1
1797	default "0"
1798	depends on MTRR_SANITIZER
1799	help
1800	  Enable mtrr cleanup default value
1801
1802config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1803	int "MTRR cleanup spare reg num (0-7)"
1804	range 0 7
1805	default "1"
1806	depends on MTRR_SANITIZER
1807	help
1808	  mtrr cleanup spare entries default, it can be changed via
1809	  mtrr_spare_reg_nr=N on the kernel command line.
1810
1811config X86_PAT
1812	def_bool y
1813	prompt "x86 PAT support" if EXPERT
1814	depends on MTRR
1815	help
1816	  Use PAT attributes to setup page level cache control.
1817
1818	  PATs are the modern equivalents of MTRRs and are much more
1819	  flexible than MTRRs.
1820
1821	  Say N here if you see bootup problems (boot crash, boot hang,
1822	  spontaneous reboots) or a non-working video driver.
1823
1824	  If unsure, say Y.
1825
1826config ARCH_USES_PG_UNCACHED
1827	def_bool y
1828	depends on X86_PAT
1829
1830config ARCH_RANDOM
1831	def_bool y
1832	prompt "x86 architectural random number generator" if EXPERT
1833	help
1834	  Enable the x86 architectural RDRAND instruction
1835	  (Intel Bull Mountain technology) to generate random numbers.
1836	  If supported, this is a high bandwidth, cryptographically
1837	  secure hardware random number generator.
1838
1839config X86_SMAP
1840	def_bool y
1841	prompt "Supervisor Mode Access Prevention" if EXPERT
1842	help
1843	  Supervisor Mode Access Prevention (SMAP) is a security
1844	  feature in newer Intel processors.  There is a small
1845	  performance cost if this enabled and turned on; there is
1846	  also a small increase in the kernel size if this is enabled.
1847
1848	  If unsure, say Y.
1849
1850config X86_UMIP
1851	def_bool y
1852	prompt "User Mode Instruction Prevention" if EXPERT
1853	help
1854	  User Mode Instruction Prevention (UMIP) is a security feature in
1855	  some x86 processors. If enabled, a general protection fault is
1856	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1857	  executed in user mode. These instructions unnecessarily expose
1858	  information about the hardware state.
1859
1860	  The vast majority of applications do not use these instructions.
1861	  For the very few that do, software emulation is provided in
1862	  specific cases in protected and virtual-8086 modes. Emulated
1863	  results are dummy.
1864
1865config X86_INTEL_MEMORY_PROTECTION_KEYS
1866	prompt "Memory Protection Keys"
1867	def_bool y
1868	# Note: only available in 64-bit mode
1869	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1870	select ARCH_USES_HIGH_VMA_FLAGS
1871	select ARCH_HAS_PKEYS
1872	help
1873	  Memory Protection Keys provides a mechanism for enforcing
1874	  page-based protections, but without requiring modification of the
1875	  page tables when an application changes protection domains.
1876
1877	  For details, see Documentation/core-api/protection-keys.rst
1878
1879	  If unsure, say y.
1880
1881choice
1882	prompt "TSX enable mode"
1883	depends on CPU_SUP_INTEL
1884	default X86_INTEL_TSX_MODE_OFF
1885	help
1886	  Intel's TSX (Transactional Synchronization Extensions) feature
1887	  allows to optimize locking protocols through lock elision which
1888	  can lead to a noticeable performance boost.
1889
1890	  On the other hand it has been shown that TSX can be exploited
1891	  to form side channel attacks (e.g. TAA) and chances are there
1892	  will be more of those attacks discovered in the future.
1893
1894	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1895	  might override this decision by tsx=on the command line parameter.
1896	  Even with TSX enabled, the kernel will attempt to enable the best
1897	  possible TAA mitigation setting depending on the microcode available
1898	  for the particular machine.
1899
1900	  This option allows to set the default tsx mode between tsx=on, =off
1901	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1902	  details.
1903
1904	  Say off if not sure, auto if TSX is in use but it should be used on safe
1905	  platforms or on if TSX is in use and the security aspect of tsx is not
1906	  relevant.
1907
1908config X86_INTEL_TSX_MODE_OFF
1909	bool "off"
1910	help
1911	  TSX is disabled if possible - equals to tsx=off command line parameter.
1912
1913config X86_INTEL_TSX_MODE_ON
1914	bool "on"
1915	help
1916	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1917	  line parameter.
1918
1919config X86_INTEL_TSX_MODE_AUTO
1920	bool "auto"
1921	help
1922	  TSX is enabled on TSX capable HW that is believed to be safe against
1923	  side channel attacks- equals the tsx=auto command line parameter.
1924endchoice
1925
1926config EFI
1927	bool "EFI runtime service support"
1928	depends on ACPI
1929	select UCS2_STRING
1930	select EFI_RUNTIME_WRAPPERS
1931	select ARCH_USE_MEMREMAP_PROT
1932	help
1933	  This enables the kernel to use EFI runtime services that are
1934	  available (such as the EFI variable services).
1935
1936	  This option is only useful on systems that have EFI firmware.
1937	  In addition, you should use the latest ELILO loader available
1938	  at <http://elilo.sourceforge.net> in order to take advantage
1939	  of EFI runtime services. However, even with this option, the
1940	  resultant kernel should continue to boot on existing non-EFI
1941	  platforms.
1942
1943config EFI_STUB
1944	bool "EFI stub support"
1945	depends on EFI && !X86_USE_3DNOW
1946	select RELOCATABLE
1947	help
1948	  This kernel feature allows a bzImage to be loaded directly
1949	  by EFI firmware without the use of a bootloader.
1950
1951	  See Documentation/admin-guide/efi-stub.rst for more information.
1952
1953config EFI_MIXED
1954	bool "EFI mixed-mode support"
1955	depends on EFI_STUB && X86_64
1956	help
1957	   Enabling this feature allows a 64-bit kernel to be booted
1958	   on a 32-bit firmware, provided that your CPU supports 64-bit
1959	   mode.
1960
1961	   Note that it is not possible to boot a mixed-mode enabled
1962	   kernel via the EFI boot stub - a bootloader that supports
1963	   the EFI handover protocol must be used.
1964
1965	   If unsure, say N.
1966
1967source "kernel/Kconfig.hz"
1968
1969config KEXEC
1970	bool "kexec system call"
1971	select KEXEC_CORE
1972	help
1973	  kexec is a system call that implements the ability to shutdown your
1974	  current kernel, and to start another kernel.  It is like a reboot
1975	  but it is independent of the system firmware.   And like a reboot
1976	  you can start any kernel with it, not just Linux.
1977
1978	  The name comes from the similarity to the exec system call.
1979
1980	  It is an ongoing process to be certain the hardware in a machine
1981	  is properly shutdown, so do not be surprised if this code does not
1982	  initially work for you.  As of this writing the exact hardware
1983	  interface is strongly in flux, so no good recommendation can be
1984	  made.
1985
1986config KEXEC_FILE
1987	bool "kexec file based system call"
1988	select KEXEC_CORE
1989	select BUILD_BIN2C
1990	depends on X86_64
1991	depends on CRYPTO=y
1992	depends on CRYPTO_SHA256=y
1993	help
1994	  This is new version of kexec system call. This system call is
1995	  file based and takes file descriptors as system call argument
1996	  for kernel and initramfs as opposed to list of segments as
1997	  accepted by previous system call.
1998
1999config ARCH_HAS_KEXEC_PURGATORY
2000	def_bool KEXEC_FILE
2001
2002config KEXEC_SIG
2003	bool "Verify kernel signature during kexec_file_load() syscall"
2004	depends on KEXEC_FILE
2005	help
2006
2007	  This option makes the kexec_file_load() syscall check for a valid
2008	  signature of the kernel image.  The image can still be loaded without
2009	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2010	  there's a signature that we can check, then it must be valid.
2011
2012	  In addition to this option, you need to enable signature
2013	  verification for the corresponding kernel image type being
2014	  loaded in order for this to work.
2015
2016config KEXEC_SIG_FORCE
2017	bool "Require a valid signature in kexec_file_load() syscall"
2018	depends on KEXEC_SIG
2019	help
2020	  This option makes kernel signature verification mandatory for
2021	  the kexec_file_load() syscall.
2022
2023config KEXEC_BZIMAGE_VERIFY_SIG
2024	bool "Enable bzImage signature verification support"
2025	depends on KEXEC_SIG
2026	depends on SIGNED_PE_FILE_VERIFICATION
2027	select SYSTEM_TRUSTED_KEYRING
2028	help
2029	  Enable bzImage signature verification support.
2030
2031config CRASH_DUMP
2032	bool "kernel crash dumps"
2033	depends on X86_64 || (X86_32 && HIGHMEM)
2034	help
2035	  Generate crash dump after being started by kexec.
2036	  This should be normally only set in special crash dump kernels
2037	  which are loaded in the main kernel with kexec-tools into
2038	  a specially reserved region and then later executed after
2039	  a crash by kdump/kexec. The crash dump kernel must be compiled
2040	  to a memory address not used by the main kernel or BIOS using
2041	  PHYSICAL_START, or it must be built as a relocatable image
2042	  (CONFIG_RELOCATABLE=y).
2043	  For more details see Documentation/admin-guide/kdump/kdump.rst
2044
2045config KEXEC_JUMP
2046	bool "kexec jump"
2047	depends on KEXEC && HIBERNATION
2048	help
2049	  Jump between original kernel and kexeced kernel and invoke
2050	  code in physical address mode via KEXEC
2051
2052config PHYSICAL_START
2053	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2054	default "0x1000000"
2055	help
2056	  This gives the physical address where the kernel is loaded.
2057
2058	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2059	  bzImage will decompress itself to above physical address and
2060	  run from there. Otherwise, bzImage will run from the address where
2061	  it has been loaded by the boot loader and will ignore above physical
2062	  address.
2063
2064	  In normal kdump cases one does not have to set/change this option
2065	  as now bzImage can be compiled as a completely relocatable image
2066	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2067	  address. This option is mainly useful for the folks who don't want
2068	  to use a bzImage for capturing the crash dump and want to use a
2069	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2070	  to be specifically compiled to run from a specific memory area
2071	  (normally a reserved region) and this option comes handy.
2072
2073	  So if you are using bzImage for capturing the crash dump,
2074	  leave the value here unchanged to 0x1000000 and set
2075	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2076	  for capturing the crash dump change this value to start of
2077	  the reserved region.  In other words, it can be set based on
2078	  the "X" value as specified in the "crashkernel=YM@XM"
2079	  command line boot parameter passed to the panic-ed
2080	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2081	  for more details about crash dumps.
2082
2083	  Usage of bzImage for capturing the crash dump is recommended as
2084	  one does not have to build two kernels. Same kernel can be used
2085	  as production kernel and capture kernel. Above option should have
2086	  gone away after relocatable bzImage support is introduced. But it
2087	  is present because there are users out there who continue to use
2088	  vmlinux for dump capture. This option should go away down the
2089	  line.
2090
2091	  Don't change this unless you know what you are doing.
2092
2093config RELOCATABLE
2094	bool "Build a relocatable kernel"
2095	default y
2096	help
2097	  This builds a kernel image that retains relocation information
2098	  so it can be loaded someplace besides the default 1MB.
2099	  The relocations tend to make the kernel binary about 10% larger,
2100	  but are discarded at runtime.
2101
2102	  One use is for the kexec on panic case where the recovery kernel
2103	  must live at a different physical address than the primary
2104	  kernel.
2105
2106	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2107	  it has been loaded at and the compile time physical address
2108	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2109
2110config RANDOMIZE_BASE
2111	bool "Randomize the address of the kernel image (KASLR)"
2112	depends on RELOCATABLE
2113	default y
2114	help
2115	  In support of Kernel Address Space Layout Randomization (KASLR),
2116	  this randomizes the physical address at which the kernel image
2117	  is decompressed and the virtual address where the kernel
2118	  image is mapped, as a security feature that deters exploit
2119	  attempts relying on knowledge of the location of kernel
2120	  code internals.
2121
2122	  On 64-bit, the kernel physical and virtual addresses are
2123	  randomized separately. The physical address will be anywhere
2124	  between 16MB and the top of physical memory (up to 64TB). The
2125	  virtual address will be randomized from 16MB up to 1GB (9 bits
2126	  of entropy). Note that this also reduces the memory space
2127	  available to kernel modules from 1.5GB to 1GB.
2128
2129	  On 32-bit, the kernel physical and virtual addresses are
2130	  randomized together. They will be randomized from 16MB up to
2131	  512MB (8 bits of entropy).
2132
2133	  Entropy is generated using the RDRAND instruction if it is
2134	  supported. If RDTSC is supported, its value is mixed into
2135	  the entropy pool as well. If neither RDRAND nor RDTSC are
2136	  supported, then entropy is read from the i8254 timer. The
2137	  usable entropy is limited by the kernel being built using
2138	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2139	  minimum of 2MB. As a result, only 10 bits of entropy are
2140	  theoretically possible, but the implementations are further
2141	  limited due to memory layouts.
2142
2143	  If unsure, say Y.
2144
2145# Relocation on x86 needs some additional build support
2146config X86_NEED_RELOCS
2147	def_bool y
2148	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2149
2150config PHYSICAL_ALIGN
2151	hex "Alignment value to which kernel should be aligned"
2152	default "0x200000"
2153	range 0x2000 0x1000000 if X86_32
2154	range 0x200000 0x1000000 if X86_64
2155	help
2156	  This value puts the alignment restrictions on physical address
2157	  where kernel is loaded and run from. Kernel is compiled for an
2158	  address which meets above alignment restriction.
2159
2160	  If bootloader loads the kernel at a non-aligned address and
2161	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2162	  address aligned to above value and run from there.
2163
2164	  If bootloader loads the kernel at a non-aligned address and
2165	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2166	  load address and decompress itself to the address it has been
2167	  compiled for and run from there. The address for which kernel is
2168	  compiled already meets above alignment restrictions. Hence the
2169	  end result is that kernel runs from a physical address meeting
2170	  above alignment restrictions.
2171
2172	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2173	  this value must be a multiple of 0x200000.
2174
2175	  Don't change this unless you know what you are doing.
2176
2177config DYNAMIC_MEMORY_LAYOUT
2178	bool
2179	help
2180	  This option makes base addresses of vmalloc and vmemmap as well as
2181	  __PAGE_OFFSET movable during boot.
2182
2183config RANDOMIZE_MEMORY
2184	bool "Randomize the kernel memory sections"
2185	depends on X86_64
2186	depends on RANDOMIZE_BASE
2187	select DYNAMIC_MEMORY_LAYOUT
2188	default RANDOMIZE_BASE
2189	help
2190	   Randomizes the base virtual address of kernel memory sections
2191	   (physical memory mapping, vmalloc & vmemmap). This security feature
2192	   makes exploits relying on predictable memory locations less reliable.
2193
2194	   The order of allocations remains unchanged. Entropy is generated in
2195	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2196	   configuration have in average 30,000 different possible virtual
2197	   addresses for each memory section.
2198
2199	   If unsure, say Y.
2200
2201config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2202	hex "Physical memory mapping padding" if EXPERT
2203	depends on RANDOMIZE_MEMORY
2204	default "0xa" if MEMORY_HOTPLUG
2205	default "0x0"
2206	range 0x1 0x40 if MEMORY_HOTPLUG
2207	range 0x0 0x40
2208	help
2209	   Define the padding in terabytes added to the existing physical
2210	   memory size during kernel memory randomization. It is useful
2211	   for memory hotplug support but reduces the entropy available for
2212	   address randomization.
2213
2214	   If unsure, leave at the default value.
2215
2216config HOTPLUG_CPU
2217	def_bool y
2218	depends on SMP
2219
2220config BOOTPARAM_HOTPLUG_CPU0
2221	bool "Set default setting of cpu0_hotpluggable"
2222	depends on HOTPLUG_CPU
2223	help
2224	  Set whether default state of cpu0_hotpluggable is on or off.
2225
2226	  Say Y here to enable CPU0 hotplug by default. If this switch
2227	  is turned on, there is no need to give cpu0_hotplug kernel
2228	  parameter and the CPU0 hotplug feature is enabled by default.
2229
2230	  Please note: there are two known CPU0 dependencies if you want
2231	  to enable the CPU0 hotplug feature either by this switch or by
2232	  cpu0_hotplug kernel parameter.
2233
2234	  First, resume from hibernate or suspend always starts from CPU0.
2235	  So hibernate and suspend are prevented if CPU0 is offline.
2236
2237	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2238	  offline if any interrupt can not migrate out of CPU0. There may
2239	  be other CPU0 dependencies.
2240
2241	  Please make sure the dependencies are under your control before
2242	  you enable this feature.
2243
2244	  Say N if you don't want to enable CPU0 hotplug feature by default.
2245	  You still can enable the CPU0 hotplug feature at boot by kernel
2246	  parameter cpu0_hotplug.
2247
2248config DEBUG_HOTPLUG_CPU0
2249	def_bool n
2250	prompt "Debug CPU0 hotplug"
2251	depends on HOTPLUG_CPU
2252	help
2253	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2254	  soon as possible and boots up userspace with CPU0 offlined. User
2255	  can online CPU0 back after boot time.
2256
2257	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2258	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2259	  compilation or giving cpu0_hotplug kernel parameter at boot.
2260
2261	  If unsure, say N.
2262
2263config COMPAT_VDSO
2264	def_bool n
2265	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2266	depends on COMPAT_32
2267	help
2268	  Certain buggy versions of glibc will crash if they are
2269	  presented with a 32-bit vDSO that is not mapped at the address
2270	  indicated in its segment table.
2271
2272	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2273	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2274	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2275	  the only released version with the bug, but OpenSUSE 9
2276	  contains a buggy "glibc 2.3.2".
2277
2278	  The symptom of the bug is that everything crashes on startup, saying:
2279	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2280
2281	  Saying Y here changes the default value of the vdso32 boot
2282	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2283	  This works around the glibc bug but hurts performance.
2284
2285	  If unsure, say N: if you are compiling your own kernel, you
2286	  are unlikely to be using a buggy version of glibc.
2287
2288choice
2289	prompt "vsyscall table for legacy applications"
2290	depends on X86_64
2291	default LEGACY_VSYSCALL_XONLY
2292	help
2293	  Legacy user code that does not know how to find the vDSO expects
2294	  to be able to issue three syscalls by calling fixed addresses in
2295	  kernel space. Since this location is not randomized with ASLR,
2296	  it can be used to assist security vulnerability exploitation.
2297
2298	  This setting can be changed at boot time via the kernel command
2299	  line parameter vsyscall=[emulate|xonly|none].
2300
2301	  On a system with recent enough glibc (2.14 or newer) and no
2302	  static binaries, you can say None without a performance penalty
2303	  to improve security.
2304
2305	  If unsure, select "Emulate execution only".
2306
2307	config LEGACY_VSYSCALL_EMULATE
2308		bool "Full emulation"
2309		help
2310		  The kernel traps and emulates calls into the fixed vsyscall
2311		  address mapping. This makes the mapping non-executable, but
2312		  it still contains readable known contents, which could be
2313		  used in certain rare security vulnerability exploits. This
2314		  configuration is recommended when using legacy userspace
2315		  that still uses vsyscalls along with legacy binary
2316		  instrumentation tools that require code to be readable.
2317
2318		  An example of this type of legacy userspace is running
2319		  Pin on an old binary that still uses vsyscalls.
2320
2321	config LEGACY_VSYSCALL_XONLY
2322		bool "Emulate execution only"
2323		help
2324		  The kernel traps and emulates calls into the fixed vsyscall
2325		  address mapping and does not allow reads.  This
2326		  configuration is recommended when userspace might use the
2327		  legacy vsyscall area but support for legacy binary
2328		  instrumentation of legacy code is not needed.  It mitigates
2329		  certain uses of the vsyscall area as an ASLR-bypassing
2330		  buffer.
2331
2332	config LEGACY_VSYSCALL_NONE
2333		bool "None"
2334		help
2335		  There will be no vsyscall mapping at all. This will
2336		  eliminate any risk of ASLR bypass due to the vsyscall
2337		  fixed address mapping. Attempts to use the vsyscalls
2338		  will be reported to dmesg, so that either old or
2339		  malicious userspace programs can be identified.
2340
2341endchoice
2342
2343config CMDLINE_BOOL
2344	bool "Built-in kernel command line"
2345	help
2346	  Allow for specifying boot arguments to the kernel at
2347	  build time.  On some systems (e.g. embedded ones), it is
2348	  necessary or convenient to provide some or all of the
2349	  kernel boot arguments with the kernel itself (that is,
2350	  to not rely on the boot loader to provide them.)
2351
2352	  To compile command line arguments into the kernel,
2353	  set this option to 'Y', then fill in the
2354	  boot arguments in CONFIG_CMDLINE.
2355
2356	  Systems with fully functional boot loaders (i.e. non-embedded)
2357	  should leave this option set to 'N'.
2358
2359config CMDLINE
2360	string "Built-in kernel command string"
2361	depends on CMDLINE_BOOL
2362	default ""
2363	help
2364	  Enter arguments here that should be compiled into the kernel
2365	  image and used at boot time.  If the boot loader provides a
2366	  command line at boot time, it is appended to this string to
2367	  form the full kernel command line, when the system boots.
2368
2369	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2370	  change this behavior.
2371
2372	  In most cases, the command line (whether built-in or provided
2373	  by the boot loader) should specify the device for the root
2374	  file system.
2375
2376config CMDLINE_OVERRIDE
2377	bool "Built-in command line overrides boot loader arguments"
2378	depends on CMDLINE_BOOL && CMDLINE != ""
2379	help
2380	  Set this option to 'Y' to have the kernel ignore the boot loader
2381	  command line, and use ONLY the built-in command line.
2382
2383	  This is used to work around broken boot loaders.  This should
2384	  be set to 'N' under normal conditions.
2385
2386config MODIFY_LDT_SYSCALL
2387	bool "Enable the LDT (local descriptor table)" if EXPERT
2388	default y
2389	help
2390	  Linux can allow user programs to install a per-process x86
2391	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2392	  call.  This is required to run 16-bit or segmented code such as
2393	  DOSEMU or some Wine programs.  It is also used by some very old
2394	  threading libraries.
2395
2396	  Enabling this feature adds a small amount of overhead to
2397	  context switches and increases the low-level kernel attack
2398	  surface.  Disabling it removes the modify_ldt(2) system call.
2399
2400	  Saying 'N' here may make sense for embedded or server kernels.
2401
2402source "kernel/livepatch/Kconfig"
2403
2404endmenu
2405
2406config CC_HAS_SLS
2407	def_bool $(cc-option,-mharden-sls=all)
2408
2409config CC_HAS_RETURN_THUNK
2410	def_bool $(cc-option,-mfunction-return=thunk-extern)
2411
2412menuconfig SPECULATION_MITIGATIONS
2413	bool "Mitigations for speculative execution vulnerabilities"
2414	default y
2415	help
2416	  Say Y here to enable options which enable mitigations for
2417	  speculative execution hardware vulnerabilities.
2418
2419	  If you say N, all mitigations will be disabled. You really
2420	  should know what you are doing to say so.
2421
2422if SPECULATION_MITIGATIONS
2423
2424config PAGE_TABLE_ISOLATION
2425	bool "Remove the kernel mapping in user mode"
2426	default y
2427	depends on (X86_64 || X86_PAE)
2428	help
2429	  This feature reduces the number of hardware side channels by
2430	  ensuring that the majority of kernel addresses are not mapped
2431	  into userspace.
2432
2433	  See Documentation/x86/pti.rst for more details.
2434
2435config RETPOLINE
2436	bool "Avoid speculative indirect branches in kernel"
2437	default y
2438	help
2439	  Compile kernel with the retpoline compiler options to guard against
2440	  kernel-to-user data leaks by avoiding speculative indirect
2441	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2442	  support for full protection. The kernel may run slower.
2443
2444config RETHUNK
2445	bool "Enable return-thunks"
2446	depends on RETPOLINE && CC_HAS_RETURN_THUNK
2447	default y if X86_64
2448	help
2449	  Compile the kernel with the return-thunks compiler option to guard
2450	  against kernel-to-user data leaks by avoiding return speculation.
2451	  Requires a compiler with -mfunction-return=thunk-extern
2452	  support for full protection. The kernel may run slower.
2453
2454config CPU_UNRET_ENTRY
2455	bool "Enable UNRET on kernel entry"
2456	depends on CPU_SUP_AMD && RETHUNK && X86_64
2457	default y
2458	help
2459	  Compile the kernel with support for the retbleed=unret mitigation.
2460
2461config CPU_IBPB_ENTRY
2462	bool "Enable IBPB on kernel entry"
2463	depends on CPU_SUP_AMD && X86_64
2464	default y
2465	help
2466	  Compile the kernel with support for the retbleed=ibpb mitigation.
2467
2468config CPU_IBRS_ENTRY
2469	bool "Enable IBRS on kernel entry"
2470	depends on CPU_SUP_INTEL && X86_64
2471	default y
2472	help
2473	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2474	  This mitigates both spectre_v2 and retbleed at great cost to
2475	  performance.
2476
2477config CPU_SRSO
2478	bool "Mitigate speculative RAS overflow on AMD"
2479	depends on CPU_SUP_AMD && X86_64 && RETHUNK
2480	default y
2481	help
2482	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2483
2484config SLS
2485	bool "Mitigate Straight-Line-Speculation"
2486	depends on CC_HAS_SLS && X86_64
2487	default n
2488	help
2489	  Compile the kernel with straight-line-speculation options to guard
2490	  against straight line speculation. The kernel image might be slightly
2491	  larger.
2492
2493config GDS_FORCE_MITIGATION
2494	bool "Force GDS Mitigation"
2495	depends on CPU_SUP_INTEL
2496	default n
2497	help
2498	  Gather Data Sampling (GDS) is a hardware vulnerability which allows
2499	  unprivileged speculative access to data which was previously stored in
2500	  vector registers.
2501
2502	  This option is equivalent to setting gather_data_sampling=force on the
2503	  command line. The microcode mitigation is used if present, otherwise
2504	  AVX is disabled as a mitigation. On affected systems that are missing
2505	  the microcode any userspace code that unconditionally uses AVX will
2506	  break with this option set.
2507
2508	  Setting this option on systems not vulnerable to GDS has no effect.
2509
2510	  If in doubt, say N.
2511
2512config MITIGATION_RFDS
2513	bool "RFDS Mitigation"
2514	depends on CPU_SUP_INTEL
2515	default y
2516	help
2517	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2518	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2519	  allows unprivileged speculative access to stale data previously
2520	  stored in floating point, vector and integer registers.
2521	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2522
2523endif
2524
2525config ARCH_HAS_ADD_PAGES
2526	def_bool y
2527	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2528
2529config ARCH_ENABLE_MEMORY_HOTPLUG
2530	def_bool y
2531	depends on X86_64 || (X86_32 && HIGHMEM)
2532
2533config ARCH_ENABLE_MEMORY_HOTREMOVE
2534	def_bool y
2535	depends on MEMORY_HOTPLUG
2536
2537config USE_PERCPU_NUMA_NODE_ID
2538	def_bool y
2539	depends on NUMA
2540
2541config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2542	def_bool y
2543	depends on X86_64 || X86_PAE
2544
2545config ARCH_ENABLE_HUGEPAGE_MIGRATION
2546	def_bool y
2547	depends on X86_64 && HUGETLB_PAGE && MIGRATION
2548
2549config ARCH_ENABLE_THP_MIGRATION
2550	def_bool y
2551	depends on X86_64 && TRANSPARENT_HUGEPAGE
2552
2553menu "Power management and ACPI options"
2554
2555config ARCH_HIBERNATION_HEADER
2556	def_bool y
2557	depends on HIBERNATION
2558
2559source "kernel/power/Kconfig"
2560
2561source "drivers/acpi/Kconfig"
2562
2563source "drivers/sfi/Kconfig"
2564
2565config X86_APM_BOOT
2566	def_bool y
2567	depends on APM
2568
2569menuconfig APM
2570	tristate "APM (Advanced Power Management) BIOS support"
2571	depends on X86_32 && PM_SLEEP
2572	help
2573	  APM is a BIOS specification for saving power using several different
2574	  techniques. This is mostly useful for battery powered laptops with
2575	  APM compliant BIOSes. If you say Y here, the system time will be
2576	  reset after a RESUME operation, the /proc/apm device will provide
2577	  battery status information, and user-space programs will receive
2578	  notification of APM "events" (e.g. battery status change).
2579
2580	  If you select "Y" here, you can disable actual use of the APM
2581	  BIOS by passing the "apm=off" option to the kernel at boot time.
2582
2583	  Note that the APM support is almost completely disabled for
2584	  machines with more than one CPU.
2585
2586	  In order to use APM, you will need supporting software. For location
2587	  and more information, read <file:Documentation/power/apm-acpi.rst>
2588	  and the Battery Powered Linux mini-HOWTO, available from
2589	  <http://www.tldp.org/docs.html#howto>.
2590
2591	  This driver does not spin down disk drives (see the hdparm(8)
2592	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2593	  VESA-compliant "green" monitors.
2594
2595	  This driver does not support the TI 4000M TravelMate and the ACER
2596	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2597	  desktop machines also don't have compliant BIOSes, and this driver
2598	  may cause those machines to panic during the boot phase.
2599
2600	  Generally, if you don't have a battery in your machine, there isn't
2601	  much point in using this driver and you should say N. If you get
2602	  random kernel OOPSes or reboots that don't seem to be related to
2603	  anything, try disabling/enabling this option (or disabling/enabling
2604	  APM in your BIOS).
2605
2606	  Some other things you should try when experiencing seemingly random,
2607	  "weird" problems:
2608
2609	  1) make sure that you have enough swap space and that it is
2610	  enabled.
2611	  2) pass the "no-hlt" option to the kernel
2612	  3) switch on floating point emulation in the kernel and pass
2613	  the "no387" option to the kernel
2614	  4) pass the "floppy=nodma" option to the kernel
2615	  5) pass the "mem=4M" option to the kernel (thereby disabling
2616	  all but the first 4 MB of RAM)
2617	  6) make sure that the CPU is not over clocked.
2618	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2619	  8) disable the cache from your BIOS settings
2620	  9) install a fan for the video card or exchange video RAM
2621	  10) install a better fan for the CPU
2622	  11) exchange RAM chips
2623	  12) exchange the motherboard.
2624
2625	  To compile this driver as a module, choose M here: the
2626	  module will be called apm.
2627
2628if APM
2629
2630config APM_IGNORE_USER_SUSPEND
2631	bool "Ignore USER SUSPEND"
2632	help
2633	  This option will ignore USER SUSPEND requests. On machines with a
2634	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2635	  series notebooks, it is necessary to say Y because of a BIOS bug.
2636
2637config APM_DO_ENABLE
2638	bool "Enable PM at boot time"
2639	help
2640	  Enable APM features at boot time. From page 36 of the APM BIOS
2641	  specification: "When disabled, the APM BIOS does not automatically
2642	  power manage devices, enter the Standby State, enter the Suspend
2643	  State, or take power saving steps in response to CPU Idle calls."
2644	  This driver will make CPU Idle calls when Linux is idle (unless this
2645	  feature is turned off -- see "Do CPU IDLE calls", below). This
2646	  should always save battery power, but more complicated APM features
2647	  will be dependent on your BIOS implementation. You may need to turn
2648	  this option off if your computer hangs at boot time when using APM
2649	  support, or if it beeps continuously instead of suspending. Turn
2650	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2651	  T400CDT. This is off by default since most machines do fine without
2652	  this feature.
2653
2654config APM_CPU_IDLE
2655	depends on CPU_IDLE
2656	bool "Make CPU Idle calls when idle"
2657	help
2658	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2659	  On some machines, this can activate improved power savings, such as
2660	  a slowed CPU clock rate, when the machine is idle. These idle calls
2661	  are made after the idle loop has run for some length of time (e.g.,
2662	  333 mS). On some machines, this will cause a hang at boot time or
2663	  whenever the CPU becomes idle. (On machines with more than one CPU,
2664	  this option does nothing.)
2665
2666config APM_DISPLAY_BLANK
2667	bool "Enable console blanking using APM"
2668	help
2669	  Enable console blanking using the APM. Some laptops can use this to
2670	  turn off the LCD backlight when the screen blanker of the Linux
2671	  virtual console blanks the screen. Note that this is only used by
2672	  the virtual console screen blanker, and won't turn off the backlight
2673	  when using the X Window system. This also doesn't have anything to
2674	  do with your VESA-compliant power-saving monitor. Further, this
2675	  option doesn't work for all laptops -- it might not turn off your
2676	  backlight at all, or it might print a lot of errors to the console,
2677	  especially if you are using gpm.
2678
2679config APM_ALLOW_INTS
2680	bool "Allow interrupts during APM BIOS calls"
2681	help
2682	  Normally we disable external interrupts while we are making calls to
2683	  the APM BIOS as a measure to lessen the effects of a badly behaving
2684	  BIOS implementation.  The BIOS should reenable interrupts if it
2685	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2686	  many of the newer IBM Thinkpads.  If you experience hangs when you
2687	  suspend, try setting this to Y.  Otherwise, say N.
2688
2689endif # APM
2690
2691source "drivers/cpufreq/Kconfig"
2692
2693source "drivers/cpuidle/Kconfig"
2694
2695source "drivers/idle/Kconfig"
2696
2697endmenu
2698
2699
2700menu "Bus options (PCI etc.)"
2701
2702choice
2703	prompt "PCI access mode"
2704	depends on X86_32 && PCI
2705	default PCI_GOANY
2706	help
2707	  On PCI systems, the BIOS can be used to detect the PCI devices and
2708	  determine their configuration. However, some old PCI motherboards
2709	  have BIOS bugs and may crash if this is done. Also, some embedded
2710	  PCI-based systems don't have any BIOS at all. Linux can also try to
2711	  detect the PCI hardware directly without using the BIOS.
2712
2713	  With this option, you can specify how Linux should detect the
2714	  PCI devices. If you choose "BIOS", the BIOS will be used,
2715	  if you choose "Direct", the BIOS won't be used, and if you
2716	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2717	  If you choose "Any", the kernel will try MMCONFIG, then the
2718	  direct access method and falls back to the BIOS if that doesn't
2719	  work. If unsure, go with the default, which is "Any".
2720
2721config PCI_GOBIOS
2722	bool "BIOS"
2723
2724config PCI_GOMMCONFIG
2725	bool "MMConfig"
2726
2727config PCI_GODIRECT
2728	bool "Direct"
2729
2730config PCI_GOOLPC
2731	bool "OLPC XO-1"
2732	depends on OLPC
2733
2734config PCI_GOANY
2735	bool "Any"
2736
2737endchoice
2738
2739config PCI_BIOS
2740	def_bool y
2741	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2742
2743# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2744config PCI_DIRECT
2745	def_bool y
2746	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2747
2748config PCI_MMCONFIG
2749	bool "Support mmconfig PCI config space access" if X86_64
2750	default y
2751	depends on PCI && (ACPI || SFI || JAILHOUSE_GUEST)
2752	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2753
2754config PCI_OLPC
2755	def_bool y
2756	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2757
2758config PCI_XEN
2759	def_bool y
2760	depends on PCI && XEN
2761	select SWIOTLB_XEN
2762
2763config MMCONF_FAM10H
2764	def_bool y
2765	depends on X86_64 && PCI_MMCONFIG && ACPI
2766
2767config PCI_CNB20LE_QUIRK
2768	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2769	depends on PCI
2770	help
2771	  Read the PCI windows out of the CNB20LE host bridge. This allows
2772	  PCI hotplug to work on systems with the CNB20LE chipset which do
2773	  not have ACPI.
2774
2775	  There's no public spec for this chipset, and this functionality
2776	  is known to be incomplete.
2777
2778	  You should say N unless you know you need this.
2779
2780config ISA_BUS
2781	bool "ISA bus support on modern systems" if EXPERT
2782	help
2783	  Expose ISA bus device drivers and options available for selection and
2784	  configuration. Enable this option if your target machine has an ISA
2785	  bus. ISA is an older system, displaced by PCI and newer bus
2786	  architectures -- if your target machine is modern, it probably does
2787	  not have an ISA bus.
2788
2789	  If unsure, say N.
2790
2791# x86_64 have no ISA slots, but can have ISA-style DMA.
2792config ISA_DMA_API
2793	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2794	default y
2795	help
2796	  Enables ISA-style DMA support for devices requiring such controllers.
2797	  If unsure, say Y.
2798
2799if X86_32
2800
2801config ISA
2802	bool "ISA support"
2803	help
2804	  Find out whether you have ISA slots on your motherboard.  ISA is the
2805	  name of a bus system, i.e. the way the CPU talks to the other stuff
2806	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2807	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2808	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2809
2810config SCx200
2811	tristate "NatSemi SCx200 support"
2812	help
2813	  This provides basic support for National Semiconductor's
2814	  (now AMD's) Geode processors.  The driver probes for the
2815	  PCI-IDs of several on-chip devices, so its a good dependency
2816	  for other scx200_* drivers.
2817
2818	  If compiled as a module, the driver is named scx200.
2819
2820config SCx200HR_TIMER
2821	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2822	depends on SCx200
2823	default y
2824	help
2825	  This driver provides a clocksource built upon the on-chip
2826	  27MHz high-resolution timer.  Its also a workaround for
2827	  NSC Geode SC-1100's buggy TSC, which loses time when the
2828	  processor goes idle (as is done by the scheduler).  The
2829	  other workaround is idle=poll boot option.
2830
2831config OLPC
2832	bool "One Laptop Per Child support"
2833	depends on !X86_PAE
2834	select GPIOLIB
2835	select OF
2836	select OF_PROMTREE
2837	select IRQ_DOMAIN
2838	select OLPC_EC
2839	help
2840	  Add support for detecting the unique features of the OLPC
2841	  XO hardware.
2842
2843config OLPC_XO1_PM
2844	bool "OLPC XO-1 Power Management"
2845	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2846	help
2847	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2848
2849config OLPC_XO1_RTC
2850	bool "OLPC XO-1 Real Time Clock"
2851	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2852	help
2853	  Add support for the XO-1 real time clock, which can be used as a
2854	  programmable wakeup source.
2855
2856config OLPC_XO1_SCI
2857	bool "OLPC XO-1 SCI extras"
2858	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2859	depends on INPUT=y
2860	select POWER_SUPPLY
2861	help
2862	  Add support for SCI-based features of the OLPC XO-1 laptop:
2863	   - EC-driven system wakeups
2864	   - Power button
2865	   - Ebook switch
2866	   - Lid switch
2867	   - AC adapter status updates
2868	   - Battery status updates
2869
2870config OLPC_XO15_SCI
2871	bool "OLPC XO-1.5 SCI extras"
2872	depends on OLPC && ACPI
2873	select POWER_SUPPLY
2874	help
2875	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2876	   - EC-driven system wakeups
2877	   - AC adapter status updates
2878	   - Battery status updates
2879
2880config ALIX
2881	bool "PCEngines ALIX System Support (LED setup)"
2882	select GPIOLIB
2883	help
2884	  This option enables system support for the PCEngines ALIX.
2885	  At present this just sets up LEDs for GPIO control on
2886	  ALIX2/3/6 boards.  However, other system specific setup should
2887	  get added here.
2888
2889	  Note: You must still enable the drivers for GPIO and LED support
2890	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2891
2892	  Note: You have to set alix.force=1 for boards with Award BIOS.
2893
2894config NET5501
2895	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2896	select GPIOLIB
2897	help
2898	  This option enables system support for the Soekris Engineering net5501.
2899
2900config GEOS
2901	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2902	select GPIOLIB
2903	depends on DMI
2904	help
2905	  This option enables system support for the Traverse Technologies GEOS.
2906
2907config TS5500
2908	bool "Technologic Systems TS-5500 platform support"
2909	depends on MELAN
2910	select CHECK_SIGNATURE
2911	select NEW_LEDS
2912	select LEDS_CLASS
2913	help
2914	  This option enables system support for the Technologic Systems TS-5500.
2915
2916endif # X86_32
2917
2918config AMD_NB
2919	def_bool y
2920	depends on CPU_SUP_AMD && PCI
2921
2922config X86_SYSFB
2923	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2924	help
2925	  Firmwares often provide initial graphics framebuffers so the BIOS,
2926	  bootloader or kernel can show basic video-output during boot for
2927	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2928	  Extensions and EFI-framebuffers for this, which are mostly limited
2929	  to x86.
2930	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2931	  framebuffers so the new generic system-framebuffer drivers can be
2932	  used on x86. If the framebuffer is not compatible with the generic
2933	  modes, it is advertised as fallback platform framebuffer so legacy
2934	  drivers like efifb, vesafb and uvesafb can pick it up.
2935	  If this option is not selected, all system framebuffers are always
2936	  marked as fallback platform framebuffers as usual.
2937
2938	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2939	  not be able to pick up generic system framebuffers if this option
2940	  is selected. You are highly encouraged to enable simplefb as
2941	  replacement if you select this option. simplefb can correctly deal
2942	  with generic system framebuffers. But you should still keep vesafb
2943	  and others enabled as fallback if a system framebuffer is
2944	  incompatible with simplefb.
2945
2946	  If unsure, say Y.
2947
2948endmenu
2949
2950
2951menu "Binary Emulations"
2952
2953config IA32_EMULATION
2954	bool "IA32 Emulation"
2955	depends on X86_64
2956	select ARCH_WANT_OLD_COMPAT_IPC
2957	select BINFMT_ELF
2958	select COMPAT_BINFMT_ELF
2959	select COMPAT_OLD_SIGACTION
2960	help
2961	  Include code to run legacy 32-bit programs under a
2962	  64-bit kernel. You should likely turn this on, unless you're
2963	  100% sure that you don't have any 32-bit programs left.
2964
2965config IA32_AOUT
2966	tristate "IA32 a.out support"
2967	depends on IA32_EMULATION
2968	depends on BROKEN
2969	help
2970	  Support old a.out binaries in the 32bit emulation.
2971
2972config X86_X32
2973	bool "x32 ABI for 64-bit mode"
2974	depends on X86_64
2975	# llvm-objcopy does not convert x86_64 .note.gnu.property or
2976	# compressed debug sections to x86_x32 properly:
2977	# https://github.com/ClangBuiltLinux/linux/issues/514
2978	# https://github.com/ClangBuiltLinux/linux/issues/1141
2979	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
2980	help
2981	  Include code to run binaries for the x32 native 32-bit ABI
2982	  for 64-bit processors.  An x32 process gets access to the
2983	  full 64-bit register file and wide data path while leaving
2984	  pointers at 32 bits for smaller memory footprint.
2985
2986	  You will need a recent binutils (2.22 or later) with
2987	  elf32_x86_64 support enabled to compile a kernel with this
2988	  option set.
2989
2990config COMPAT_32
2991	def_bool y
2992	depends on IA32_EMULATION || X86_32
2993	select HAVE_UID16
2994	select OLD_SIGSUSPEND3
2995
2996config COMPAT
2997	def_bool y
2998	depends on IA32_EMULATION || X86_X32
2999
3000if COMPAT
3001config COMPAT_FOR_U64_ALIGNMENT
3002	def_bool y
3003
3004config SYSVIPC_COMPAT
3005	def_bool y
3006	depends on SYSVIPC
3007endif
3008
3009endmenu
3010
3011
3012config HAVE_ATOMIC_IOMAP
3013	def_bool y
3014	depends on X86_32
3015
3016source "drivers/firmware/Kconfig"
3017
3018source "arch/x86/kvm/Kconfig"
3019
3020source "arch/x86/Kconfig.assembler"
3021