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