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