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