xref: /openbmc/linux/arch/x86/Kconfig (revision dfc66bef)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select GENERIC_VDSO_32
18	select HAVE_DEBUG_STACKOVERFLOW
19	select KMAP_LOCAL
20	select MODULES_USE_ELF_REL
21	select OLD_SIGACTION
22	select ARCH_SPLIT_ARG64
23
24config X86_64
25	def_bool y
26	depends on 64BIT
27	# Options that are inherently 64-bit kernel only:
28	select ARCH_HAS_GIGANTIC_PAGE
29	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30	select ARCH_USE_CMPXCHG_LOCKREF
31	select HAVE_ARCH_SOFT_DIRTY
32	select MODULES_USE_ELF_RELA
33	select NEED_DMA_MAP_STATE
34	select SWIOTLB
35	select ARCH_HAS_ELFCORE_COMPAT
36	select ZONE_DMA32
37
38config FORCE_DYNAMIC_FTRACE
39	def_bool y
40	depends on X86_32
41	depends on FUNCTION_TRACER
42	select DYNAMIC_FTRACE
43	help
44	 We keep the static function tracing (!DYNAMIC_FTRACE) around
45	 in order to test the non static function tracing in the
46	 generic code, as other architectures still use it. But we
47	 only need to keep it around for x86_64. No need to keep it
48	 for x86_32. For x86_32, force DYNAMIC_FTRACE.
49#
50# Arch settings
51#
52# ( Note that options that are marked 'if X86_64' could in principle be
53#   ported to 32-bit as well. )
54#
55config X86
56	def_bool y
57	#
58	# Note: keep this list sorted alphabetically
59	#
60	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
61	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
62	select ARCH_32BIT_OFF_T			if X86_32
63	select ARCH_CLOCKSOURCE_INIT
64	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
65	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
66	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
67	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
68	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
69	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
70	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
71	select ARCH_HAS_CACHE_LINE_SIZE
72	select ARCH_HAS_DEBUG_VIRTUAL
73	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
74	select ARCH_HAS_DEVMEM_IS_ALLOWED
75	select ARCH_HAS_EARLY_DEBUG		if KGDB
76	select ARCH_HAS_ELF_RANDOMIZE
77	select ARCH_HAS_FAST_MULTIPLIER
78	select ARCH_HAS_FILTER_PGPROT
79	select ARCH_HAS_FORTIFY_SOURCE
80	select ARCH_HAS_GCOV_PROFILE_ALL
81	select ARCH_HAS_KCOV			if X86_64 && STACK_VALIDATION
82	select ARCH_HAS_MEM_ENCRYPT
83	select ARCH_HAS_MEMBARRIER_SYNC_CORE
84	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
85	select ARCH_HAS_PMEM_API		if X86_64
86	select ARCH_HAS_PTE_DEVMAP		if X86_64
87	select ARCH_HAS_PTE_SPECIAL
88	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
89	select ARCH_HAS_COPY_MC			if X86_64
90	select ARCH_HAS_SET_MEMORY
91	select ARCH_HAS_SET_DIRECT_MAP
92	select ARCH_HAS_STRICT_KERNEL_RWX
93	select ARCH_HAS_STRICT_MODULE_RWX
94	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
95	select ARCH_HAS_SYSCALL_WRAPPER
96	select ARCH_HAS_UBSAN_SANITIZE_ALL
97	select ARCH_HAS_DEBUG_WX
98	select ARCH_HAS_ZONE_DMA_SET if EXPERT
99	select ARCH_HAVE_NMI_SAFE_CMPXCHG
100	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
101	select ARCH_MIGHT_HAVE_PC_PARPORT
102	select ARCH_MIGHT_HAVE_PC_SERIO
103	select ARCH_STACKWALK
104	select ARCH_SUPPORTS_ACPI
105	select ARCH_SUPPORTS_ATOMIC_RMW
106	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
107	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
108	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
109	select ARCH_SUPPORTS_LTO_CLANG
110	select ARCH_SUPPORTS_LTO_CLANG_THIN
111	select ARCH_USE_BUILTIN_BSWAP
112	select ARCH_USE_MEMTEST
113	select ARCH_USE_QUEUED_RWLOCKS
114	select ARCH_USE_QUEUED_SPINLOCKS
115	select ARCH_USE_SYM_ANNOTATIONS
116	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
117	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
118	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
119	select ARCH_WANTS_NO_INSTR
120	select ARCH_WANT_HUGE_PMD_SHARE
121	select ARCH_WANT_LD_ORPHAN_WARN
122	select ARCH_WANTS_THP_SWAP		if X86_64
123	select ARCH_HAS_PARANOID_L1D_FLUSH
124	select BUILDTIME_TABLE_SORT
125	select CLKEVT_I8253
126	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
127	select CLOCKSOURCE_WATCHDOG
128	select DCACHE_WORD_ACCESS
129	select DYNAMIC_SIGFRAME
130	select EDAC_ATOMIC_SCRUB
131	select EDAC_SUPPORT
132	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
133	select GENERIC_CLOCKEVENTS_MIN_ADJUST
134	select GENERIC_CMOS_UPDATE
135	select GENERIC_CPU_AUTOPROBE
136	select GENERIC_CPU_VULNERABILITIES
137	select GENERIC_EARLY_IOREMAP
138	select GENERIC_ENTRY
139	select GENERIC_FIND_FIRST_BIT
140	select GENERIC_IOMAP
141	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
142	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
143	select GENERIC_IRQ_MIGRATION		if SMP
144	select GENERIC_IRQ_PROBE
145	select GENERIC_IRQ_RESERVATION_MODE
146	select GENERIC_IRQ_SHOW
147	select GENERIC_PENDING_IRQ		if SMP
148	select GENERIC_PTDUMP
149	select GENERIC_SMP_IDLE_THREAD
150	select GENERIC_TIME_VSYSCALL
151	select GENERIC_GETTIMEOFDAY
152	select GENERIC_VDSO_TIME_NS
153	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
154	select HARDIRQS_SW_RESEND
155	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
156	select HAVE_ACPI_APEI			if ACPI
157	select HAVE_ACPI_APEI_NMI		if ACPI
158	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
159	select HAVE_ARCH_AUDITSYSCALL
160	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
161	select HAVE_ARCH_JUMP_LABEL
162	select HAVE_ARCH_JUMP_LABEL_RELATIVE
163	select HAVE_ARCH_KASAN			if X86_64
164	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
165	select HAVE_ARCH_KFENCE
166	select HAVE_ARCH_KGDB
167	select HAVE_ARCH_MMAP_RND_BITS		if MMU
168	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
169	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
170	select HAVE_ARCH_PREL32_RELOCATIONS
171	select HAVE_ARCH_SECCOMP_FILTER
172	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
173	select HAVE_ARCH_STACKLEAK
174	select HAVE_ARCH_TRACEHOOK
175	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
176	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
177	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
178	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
179	select HAVE_ARCH_VMAP_STACK		if X86_64
180	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
181	select HAVE_ARCH_WITHIN_STACK_FRAMES
182	select HAVE_ASM_MODVERSIONS
183	select HAVE_CMPXCHG_DOUBLE
184	select HAVE_CMPXCHG_LOCAL
185	select HAVE_CONTEXT_TRACKING		if X86_64
186	select HAVE_CONTEXT_TRACKING_OFFSTACK	if HAVE_CONTEXT_TRACKING
187	select HAVE_C_RECORDMCOUNT
188	select HAVE_OBJTOOL_MCOUNT		if STACK_VALIDATION
189	select HAVE_DEBUG_KMEMLEAK
190	select HAVE_DMA_CONTIGUOUS
191	select HAVE_DYNAMIC_FTRACE
192	select HAVE_DYNAMIC_FTRACE_WITH_REGS
193	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
194	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
195	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
196	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
197	select HAVE_EBPF_JIT
198	select HAVE_EFFICIENT_UNALIGNED_ACCESS
199	select HAVE_EISA
200	select HAVE_EXIT_THREAD
201	select HAVE_FAST_GUP
202	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
203	select HAVE_FTRACE_MCOUNT_RECORD
204	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
205	select HAVE_FUNCTION_TRACER
206	select HAVE_GCC_PLUGINS
207	select HAVE_HW_BREAKPOINT
208	select HAVE_IOREMAP_PROT
209	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
210	select HAVE_IRQ_TIME_ACCOUNTING
211	select HAVE_KERNEL_BZIP2
212	select HAVE_KERNEL_GZIP
213	select HAVE_KERNEL_LZ4
214	select HAVE_KERNEL_LZMA
215	select HAVE_KERNEL_LZO
216	select HAVE_KERNEL_XZ
217	select HAVE_KERNEL_ZSTD
218	select HAVE_KPROBES
219	select HAVE_KPROBES_ON_FTRACE
220	select HAVE_FUNCTION_ERROR_INJECTION
221	select HAVE_KRETPROBES
222	select HAVE_KVM
223	select HAVE_LIVEPATCH			if X86_64
224	select HAVE_MIXED_BREAKPOINTS_REGS
225	select HAVE_MOD_ARCH_SPECIFIC
226	select HAVE_MOVE_PMD
227	select HAVE_MOVE_PUD
228	select HAVE_NMI
229	select HAVE_OPTPROBES
230	select HAVE_PCSPKR_PLATFORM
231	select HAVE_PERF_EVENTS
232	select HAVE_PERF_EVENTS_NMI
233	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
234	select HAVE_PCI
235	select HAVE_PERF_REGS
236	select HAVE_PERF_USER_STACK_DUMP
237	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
238	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
239	select HAVE_REGS_AND_STACK_ACCESS_API
240	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
241	select HAVE_FUNCTION_ARG_ACCESS_API
242	select HAVE_SOFTIRQ_ON_OWN_STACK
243	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
244	select HAVE_STACK_VALIDATION		if X86_64
245	select HAVE_STATIC_CALL
246	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
247	select HAVE_PREEMPT_DYNAMIC
248	select HAVE_RSEQ
249	select HAVE_SYSCALL_TRACEPOINTS
250	select HAVE_UNSTABLE_SCHED_CLOCK
251	select HAVE_USER_RETURN_NOTIFIER
252	select HAVE_GENERIC_VDSO
253	select HOTPLUG_SMT			if SMP
254	select IRQ_FORCED_THREADING
255	select NEED_SG_DMA_LENGTH
256	select PCI_DOMAINS			if PCI
257	select PCI_LOCKLESS_CONFIG		if PCI
258	select PERF_EVENTS
259	select RTC_LIB
260	select RTC_MC146818_LIB
261	select SPARSE_IRQ
262	select SRCU
263	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
264	select SYSCTL_EXCEPTION_TRACE
265	select THREAD_INFO_IN_TASK
266	select TRACE_IRQFLAGS_SUPPORT
267	select USER_STACKTRACE_SUPPORT
268	select VIRT_TO_BUS
269	select HAVE_ARCH_KCSAN			if X86_64
270	select X86_FEATURE_NAMES		if PROC_FS
271	select PROC_PID_ARCH_STATUS		if PROC_FS
272	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
273	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
274
275config INSTRUCTION_DECODER
276	def_bool y
277	depends on KPROBES || PERF_EVENTS || UPROBES
278
279config OUTPUT_FORMAT
280	string
281	default "elf32-i386" if X86_32
282	default "elf64-x86-64" if X86_64
283
284config LOCKDEP_SUPPORT
285	def_bool y
286
287config STACKTRACE_SUPPORT
288	def_bool y
289
290config MMU
291	def_bool y
292
293config ARCH_MMAP_RND_BITS_MIN
294	default 28 if 64BIT
295	default 8
296
297config ARCH_MMAP_RND_BITS_MAX
298	default 32 if 64BIT
299	default 16
300
301config ARCH_MMAP_RND_COMPAT_BITS_MIN
302	default 8
303
304config ARCH_MMAP_RND_COMPAT_BITS_MAX
305	default 16
306
307config SBUS
308	bool
309
310config GENERIC_ISA_DMA
311	def_bool y
312	depends on ISA_DMA_API
313
314config GENERIC_BUG
315	def_bool y
316	depends on BUG
317	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
318
319config GENERIC_BUG_RELATIVE_POINTERS
320	bool
321
322config ARCH_MAY_HAVE_PC_FDC
323	def_bool y
324	depends on ISA_DMA_API
325
326config GENERIC_CALIBRATE_DELAY
327	def_bool y
328
329config ARCH_HAS_CPU_RELAX
330	def_bool y
331
332config ARCH_HAS_FILTER_PGPROT
333	def_bool y
334
335config HAVE_SETUP_PER_CPU_AREA
336	def_bool y
337
338config NEED_PER_CPU_EMBED_FIRST_CHUNK
339	def_bool y
340
341config NEED_PER_CPU_PAGE_FIRST_CHUNK
342	def_bool y
343
344config ARCH_HIBERNATION_POSSIBLE
345	def_bool y
346
347config ARCH_NR_GPIO
348	int
349	default 1024 if X86_64
350	default 512
351
352config ARCH_SUSPEND_POSSIBLE
353	def_bool y
354
355config ARCH_WANT_GENERAL_HUGETLB
356	def_bool y
357
358config AUDIT_ARCH
359	def_bool y if X86_64
360
361config KASAN_SHADOW_OFFSET
362	hex
363	depends on KASAN
364	default 0xdffffc0000000000
365
366config HAVE_INTEL_TXT
367	def_bool y
368	depends on INTEL_IOMMU && ACPI
369
370config X86_32_SMP
371	def_bool y
372	depends on X86_32 && SMP
373
374config X86_64_SMP
375	def_bool y
376	depends on X86_64 && SMP
377
378config ARCH_SUPPORTS_UPROBES
379	def_bool y
380
381config FIX_EARLYCON_MEM
382	def_bool y
383
384config DYNAMIC_PHYSICAL_MASK
385	bool
386
387config PGTABLE_LEVELS
388	int
389	default 5 if X86_5LEVEL
390	default 4 if X86_64
391	default 3 if X86_PAE
392	default 2
393
394config CC_HAS_SANE_STACKPROTECTOR
395	bool
396	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
397	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
398	help
399	   We have to make sure stack protector is unconditionally disabled if
400	   the compiler produces broken code or if it does not let us control
401	   the segment on 32-bit kernels.
402
403menu "Processor type and features"
404
405config SMP
406	bool "Symmetric multi-processing support"
407	help
408	  This enables support for systems with more than one CPU. If you have
409	  a system with only one CPU, say N. If you have a system with more
410	  than one CPU, say Y.
411
412	  If you say N here, the kernel will run on uni- and multiprocessor
413	  machines, but will use only one CPU of a multiprocessor machine. If
414	  you say Y here, the kernel will run on many, but not all,
415	  uniprocessor machines. On a uniprocessor machine, the kernel
416	  will run faster if you say N here.
417
418	  Note that if you say Y here and choose architecture "586" or
419	  "Pentium" under "Processor family", the kernel will not work on 486
420	  architectures. Similarly, multiprocessor kernels for the "PPro"
421	  architecture may not work on all Pentium based boards.
422
423	  People using multiprocessor machines who say Y here should also say
424	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
425	  Management" code will be disabled if you say Y here.
426
427	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
428	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
429	  <http://www.tldp.org/docs.html#howto>.
430
431	  If you don't know what to do here, say N.
432
433config X86_FEATURE_NAMES
434	bool "Processor feature human-readable names" if EMBEDDED
435	default y
436	help
437	  This option compiles in a table of x86 feature bits and corresponding
438	  names.  This is required to support /proc/cpuinfo and a few kernel
439	  messages.  You can disable this to save space, at the expense of
440	  making those few kernel messages show numeric feature bits instead.
441
442	  If in doubt, say Y.
443
444config X86_X2APIC
445	bool "Support x2apic"
446	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
447	help
448	  This enables x2apic support on CPUs that have this feature.
449
450	  This allows 32-bit apic IDs (so it can support very large systems),
451	  and accesses the local apic via MSRs not via mmio.
452
453	  If you don't know what to do here, say N.
454
455config X86_MPPARSE
456	bool "Enable MPS table" if ACPI
457	default y
458	depends on X86_LOCAL_APIC
459	help
460	  For old smp systems that do not have proper acpi support. Newer systems
461	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
462
463config GOLDFISH
464	def_bool y
465	depends on X86_GOLDFISH
466
467config RETPOLINE
468	bool "Avoid speculative indirect branches in kernel"
469	default y
470	help
471	  Compile kernel with the retpoline compiler options to guard against
472	  kernel-to-user data leaks by avoiding speculative indirect
473	  branches. Requires a compiler with -mindirect-branch=thunk-extern
474	  support for full protection. The kernel may run slower.
475
476config X86_CPU_RESCTRL
477	bool "x86 CPU resource control support"
478	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
479	select KERNFS
480	select PROC_CPU_RESCTRL		if PROC_FS
481	help
482	  Enable x86 CPU resource control support.
483
484	  Provide support for the allocation and monitoring of system resources
485	  usage by the CPU.
486
487	  Intel calls this Intel Resource Director Technology
488	  (Intel(R) RDT). More information about RDT can be found in the
489	  Intel x86 Architecture Software Developer Manual.
490
491	  AMD calls this AMD Platform Quality of Service (AMD QoS).
492	  More information about AMD QoS can be found in the AMD64 Technology
493	  Platform Quality of Service Extensions manual.
494
495	  Say N if unsure.
496
497if X86_32
498config X86_BIGSMP
499	bool "Support for big SMP systems with more than 8 CPUs"
500	depends on SMP
501	help
502	  This option is needed for the systems that have more than 8 CPUs.
503
504config X86_EXTENDED_PLATFORM
505	bool "Support for extended (non-PC) x86 platforms"
506	default y
507	help
508	  If you disable this option then the kernel will only support
509	  standard PC platforms. (which covers the vast majority of
510	  systems out there.)
511
512	  If you enable this option then you'll be able to select support
513	  for the following (non-PC) 32 bit x86 platforms:
514		Goldfish (Android emulator)
515		AMD Elan
516		RDC R-321x SoC
517		SGI 320/540 (Visual Workstation)
518		STA2X11-based (e.g. Northville)
519		Moorestown MID devices
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
525if X86_64
526config X86_EXTENDED_PLATFORM
527	bool "Support for extended (non-PC) x86 platforms"
528	default y
529	help
530	  If you disable this option then the kernel will only support
531	  standard PC platforms. (which covers the vast majority of
532	  systems out there.)
533
534	  If you enable this option then you'll be able to select support
535	  for the following (non-PC) 64 bit x86 platforms:
536		Numascale NumaChip
537		ScaleMP vSMP
538		SGI Ultraviolet
539
540	  If you have one of these systems, or if you want to build a
541	  generic distribution kernel, say Y here - otherwise say N.
542endif
543# This is an alphabetically sorted list of 64 bit extended platforms
544# Please maintain the alphabetic order if and when there are additions
545config X86_NUMACHIP
546	bool "Numascale NumaChip"
547	depends on X86_64
548	depends on X86_EXTENDED_PLATFORM
549	depends on NUMA
550	depends on SMP
551	depends on X86_X2APIC
552	depends on PCI_MMCONFIG
553	help
554	  Adds support for Numascale NumaChip large-SMP systems. Needed to
555	  enable more than ~168 cores.
556	  If you don't have one of these, you should say N here.
557
558config X86_VSMP
559	bool "ScaleMP vSMP"
560	select HYPERVISOR_GUEST
561	select PARAVIRT
562	depends on X86_64 && PCI
563	depends on X86_EXTENDED_PLATFORM
564	depends on SMP
565	help
566	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
567	  supposed to run on these EM64T-based machines.  Only choose this option
568	  if you have one of these machines.
569
570config X86_UV
571	bool "SGI Ultraviolet"
572	depends on X86_64
573	depends on X86_EXTENDED_PLATFORM
574	depends on NUMA
575	depends on EFI
576	depends on KEXEC_CORE
577	depends on X86_X2APIC
578	depends on PCI
579	help
580	  This option is needed in order to support SGI Ultraviolet systems.
581	  If you don't have one of these, you should say N here.
582
583# Following is an alphabetically sorted list of 32 bit extended platforms
584# Please maintain the alphabetic order if and when there are additions
585
586config X86_GOLDFISH
587	bool "Goldfish (Virtual Platform)"
588	depends on X86_EXTENDED_PLATFORM
589	help
590	 Enable support for the Goldfish virtual platform used primarily
591	 for Android development. Unless you are building for the Android
592	 Goldfish emulator say N here.
593
594config X86_INTEL_CE
595	bool "CE4100 TV platform"
596	depends on PCI
597	depends on PCI_GODIRECT
598	depends on X86_IO_APIC
599	depends on X86_32
600	depends on X86_EXTENDED_PLATFORM
601	select X86_REBOOTFIXUPS
602	select OF
603	select OF_EARLY_FLATTREE
604	help
605	  Select for the Intel CE media processor (CE4100) SOC.
606	  This option compiles in support for the CE4100 SOC for settop
607	  boxes and media devices.
608
609config X86_INTEL_MID
610	bool "Intel MID platform support"
611	depends on X86_EXTENDED_PLATFORM
612	depends on X86_PLATFORM_DEVICES
613	depends on PCI
614	depends on X86_64 || (PCI_GOANY && X86_32)
615	depends on X86_IO_APIC
616	select I2C
617	select DW_APB_TIMER
618	select INTEL_SCU_PCI
619	help
620	  Select to build a kernel capable of supporting Intel MID (Mobile
621	  Internet Device) platform systems which do not have the PCI legacy
622	  interfaces. If you are building for a PC class system say N here.
623
624	  Intel MID platforms are based on an Intel processor and chipset which
625	  consume less power than most of the x86 derivatives.
626
627config X86_INTEL_QUARK
628	bool "Intel Quark platform support"
629	depends on X86_32
630	depends on X86_EXTENDED_PLATFORM
631	depends on X86_PLATFORM_DEVICES
632	depends on X86_TSC
633	depends on PCI
634	depends on PCI_GOANY
635	depends on X86_IO_APIC
636	select IOSF_MBI
637	select INTEL_IMR
638	select COMMON_CLK
639	help
640	  Select to include support for Quark X1000 SoC.
641	  Say Y here if you have a Quark based system such as the Arduino
642	  compatible Intel Galileo.
643
644config X86_INTEL_LPSS
645	bool "Intel Low Power Subsystem Support"
646	depends on X86 && ACPI && PCI
647	select COMMON_CLK
648	select PINCTRL
649	select IOSF_MBI
650	help
651	  Select to build support for Intel Low Power Subsystem such as
652	  found on Intel Lynxpoint PCH. Selecting this option enables
653	  things like clock tree (common clock framework) and pincontrol
654	  which are needed by the LPSS peripheral drivers.
655
656config X86_AMD_PLATFORM_DEVICE
657	bool "AMD ACPI2Platform devices support"
658	depends on ACPI
659	select COMMON_CLK
660	select PINCTRL
661	help
662	  Select to interpret AMD specific ACPI device to platform device
663	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
664	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
665	  implemented under PINCTRL subsystem.
666
667config IOSF_MBI
668	tristate "Intel SoC IOSF Sideband support for SoC platforms"
669	depends on PCI
670	help
671	  This option enables sideband register access support for Intel SoC
672	  platforms. On these platforms the IOSF sideband is used in lieu of
673	  MSR's for some register accesses, mostly but not limited to thermal
674	  and power. Drivers may query the availability of this device to
675	  determine if they need the sideband in order to work on these
676	  platforms. The sideband is available on the following SoC products.
677	  This list is not meant to be exclusive.
678	   - BayTrail
679	   - Braswell
680	   - Quark
681
682	  You should say Y if you are running a kernel on one of these SoC's.
683
684config IOSF_MBI_DEBUG
685	bool "Enable IOSF sideband access through debugfs"
686	depends on IOSF_MBI && DEBUG_FS
687	help
688	  Select this option to expose the IOSF sideband access registers (MCR,
689	  MDR, MCRX) through debugfs to write and read register information from
690	  different units on the SoC. This is most useful for obtaining device
691	  state information for debug and analysis. As this is a general access
692	  mechanism, users of this option would have specific knowledge of the
693	  device they want to access.
694
695	  If you don't require the option or are in doubt, say N.
696
697config X86_RDC321X
698	bool "RDC R-321x SoC"
699	depends on X86_32
700	depends on X86_EXTENDED_PLATFORM
701	select M486
702	select X86_REBOOTFIXUPS
703	help
704	  This option is needed for RDC R-321x system-on-chip, also known
705	  as R-8610-(G).
706	  If you don't have one of these chips, you should say N here.
707
708config X86_32_NON_STANDARD
709	bool "Support non-standard 32-bit SMP architectures"
710	depends on X86_32 && SMP
711	depends on X86_EXTENDED_PLATFORM
712	help
713	  This option compiles in the bigsmp and STA2X11 default
714	  subarchitectures.  It is intended for a generic binary
715	  kernel. If you select them all, kernel will probe it one by
716	  one and will fallback to default.
717
718# Alphabetically sorted list of Non standard 32 bit platforms
719
720config X86_SUPPORTS_MEMORY_FAILURE
721	def_bool y
722	# MCE code calls memory_failure():
723	depends on X86_MCE
724	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
725	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
726	depends on X86_64 || !SPARSEMEM
727	select ARCH_SUPPORTS_MEMORY_FAILURE
728
729config STA2X11
730	bool "STA2X11 Companion Chip Support"
731	depends on X86_32_NON_STANDARD && PCI
732	select SWIOTLB
733	select MFD_STA2X11
734	select GPIOLIB
735	help
736	  This adds support for boards based on the STA2X11 IO-Hub,
737	  a.k.a. "ConneXt". The chip is used in place of the standard
738	  PC chipset, so all "standard" peripherals are missing. If this
739	  option is selected the kernel will still be able to boot on
740	  standard PC machines.
741
742config X86_32_IRIS
743	tristate "Eurobraille/Iris poweroff module"
744	depends on X86_32
745	help
746	  The Iris machines from EuroBraille do not have APM or ACPI support
747	  to shut themselves down properly.  A special I/O sequence is
748	  needed to do so, which is what this module does at
749	  kernel shutdown.
750
751	  This is only for Iris machines from EuroBraille.
752
753	  If unused, say N.
754
755config SCHED_OMIT_FRAME_POINTER
756	def_bool y
757	prompt "Single-depth WCHAN output"
758	depends on X86
759	help
760	  Calculate simpler /proc/<PID>/wchan values. If this option
761	  is disabled then wchan values will recurse back to the
762	  caller function. This provides more accurate wchan values,
763	  at the expense of slightly more scheduling overhead.
764
765	  If in doubt, say "Y".
766
767menuconfig HYPERVISOR_GUEST
768	bool "Linux guest support"
769	help
770	  Say Y here to enable options for running Linux under various hyper-
771	  visors. This option enables basic hypervisor detection and platform
772	  setup.
773
774	  If you say N, all options in this submenu will be skipped and
775	  disabled, and Linux guest support won't be built in.
776
777if HYPERVISOR_GUEST
778
779config PARAVIRT
780	bool "Enable paravirtualization code"
781	depends on HAVE_STATIC_CALL
782	help
783	  This changes the kernel so it can modify itself when it is run
784	  under a hypervisor, potentially improving performance significantly
785	  over full virtualization.  However, when run without a hypervisor
786	  the kernel is theoretically slower and slightly larger.
787
788config PARAVIRT_XXL
789	bool
790
791config PARAVIRT_DEBUG
792	bool "paravirt-ops debugging"
793	depends on PARAVIRT && DEBUG_KERNEL
794	help
795	  Enable to debug paravirt_ops internals.  Specifically, BUG if
796	  a paravirt_op is missing when it is called.
797
798config PARAVIRT_SPINLOCKS
799	bool "Paravirtualization layer for spinlocks"
800	depends on PARAVIRT && SMP
801	help
802	  Paravirtualized spinlocks allow a pvops backend to replace the
803	  spinlock implementation with something virtualization-friendly
804	  (for example, block the virtual CPU rather than spinning).
805
806	  It has a minimal impact on native kernels and gives a nice performance
807	  benefit on paravirtualized KVM / Xen kernels.
808
809	  If you are unsure how to answer this question, answer Y.
810
811config X86_HV_CALLBACK_VECTOR
812	def_bool n
813
814source "arch/x86/xen/Kconfig"
815
816config KVM_GUEST
817	bool "KVM Guest support (including kvmclock)"
818	depends on PARAVIRT
819	select PARAVIRT_CLOCK
820	select ARCH_CPUIDLE_HALTPOLL
821	select X86_HV_CALLBACK_VECTOR
822	default y
823	help
824	  This option enables various optimizations for running under the KVM
825	  hypervisor. It includes a paravirtualized clock, so that instead
826	  of relying on a PIT (or probably other) emulation by the
827	  underlying device model, the host provides the guest with
828	  timing infrastructure such as time of day, and system time
829
830config ARCH_CPUIDLE_HALTPOLL
831	def_bool n
832	prompt "Disable host haltpoll when loading haltpoll driver"
833	help
834	  If virtualized under KVM, disable host haltpoll.
835
836config PVH
837	bool "Support for running PVH guests"
838	help
839	  This option enables the PVH entry point for guest virtual machines
840	  as specified in the x86/HVM direct boot ABI.
841
842config PARAVIRT_TIME_ACCOUNTING
843	bool "Paravirtual steal time accounting"
844	depends on PARAVIRT
845	help
846	  Select this option to enable fine granularity task steal time
847	  accounting. Time spent executing other tasks in parallel with
848	  the current vCPU is discounted from the vCPU power. To account for
849	  that, there can be a small performance impact.
850
851	  If in doubt, say N here.
852
853config PARAVIRT_CLOCK
854	bool
855
856config JAILHOUSE_GUEST
857	bool "Jailhouse non-root cell support"
858	depends on X86_64 && PCI
859	select X86_PM_TIMER
860	help
861	  This option allows to run Linux as guest in a Jailhouse non-root
862	  cell. You can leave this option disabled if you only want to start
863	  Jailhouse and run Linux afterwards in the root cell.
864
865config ACRN_GUEST
866	bool "ACRN Guest support"
867	depends on X86_64
868	select X86_HV_CALLBACK_VECTOR
869	help
870	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
871	  a flexible, lightweight reference open-source hypervisor, built with
872	  real-time and safety-criticality in mind. It is built for embedded
873	  IOT with small footprint and real-time features. More details can be
874	  found in https://projectacrn.org/.
875
876endif #HYPERVISOR_GUEST
877
878source "arch/x86/Kconfig.cpu"
879
880config HPET_TIMER
881	def_bool X86_64
882	prompt "HPET Timer Support" if X86_32
883	help
884	  Use the IA-PC HPET (High Precision Event Timer) to manage
885	  time in preference to the PIT and RTC, if a HPET is
886	  present.
887	  HPET is the next generation timer replacing legacy 8254s.
888	  The HPET provides a stable time base on SMP
889	  systems, unlike the TSC, but it is more expensive to access,
890	  as it is off-chip.  The interface used is documented
891	  in the HPET spec, revision 1.
892
893	  You can safely choose Y here.  However, HPET will only be
894	  activated if the platform and the BIOS support this feature.
895	  Otherwise the 8254 will be used for timing services.
896
897	  Choose N to continue using the legacy 8254 timer.
898
899config HPET_EMULATE_RTC
900	def_bool y
901	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
902
903# Mark as expert because too many people got it wrong.
904# The code disables itself when not needed.
905config DMI
906	default y
907	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
908	bool "Enable DMI scanning" if EXPERT
909	help
910	  Enabled scanning of DMI to identify machine quirks. Say Y
911	  here unless you have verified that your setup is not
912	  affected by entries in the DMI blacklist. Required by PNP
913	  BIOS code.
914
915config GART_IOMMU
916	bool "Old AMD GART IOMMU support"
917	select DMA_OPS
918	select IOMMU_HELPER
919	select SWIOTLB
920	depends on X86_64 && PCI && AMD_NB
921	help
922	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
923	  GART based hardware IOMMUs.
924
925	  The GART supports full DMA access for devices with 32-bit access
926	  limitations, on systems with more than 3 GB. This is usually needed
927	  for USB, sound, many IDE/SATA chipsets and some other devices.
928
929	  Newer systems typically have a modern AMD IOMMU, supported via
930	  the CONFIG_AMD_IOMMU=y config option.
931
932	  In normal configurations this driver is only active when needed:
933	  there's more than 3 GB of memory and the system contains a
934	  32-bit limited device.
935
936	  If unsure, say Y.
937
938config MAXSMP
939	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
940	depends on X86_64 && SMP && DEBUG_KERNEL
941	select CPUMASK_OFFSTACK
942	help
943	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
944	  If unsure, say N.
945
946#
947# The maximum number of CPUs supported:
948#
949# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
950# and which can be configured interactively in the
951# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
952#
953# The ranges are different on 32-bit and 64-bit kernels, depending on
954# hardware capabilities and scalability features of the kernel.
955#
956# ( If MAXSMP is enabled we just use the highest possible value and disable
957#   interactive configuration. )
958#
959
960config NR_CPUS_RANGE_BEGIN
961	int
962	default NR_CPUS_RANGE_END if MAXSMP
963	default    1 if !SMP
964	default    2
965
966config NR_CPUS_RANGE_END
967	int
968	depends on X86_32
969	default   64 if  SMP &&  X86_BIGSMP
970	default    8 if  SMP && !X86_BIGSMP
971	default    1 if !SMP
972
973config NR_CPUS_RANGE_END
974	int
975	depends on X86_64
976	default 8192 if  SMP && CPUMASK_OFFSTACK
977	default  512 if  SMP && !CPUMASK_OFFSTACK
978	default    1 if !SMP
979
980config NR_CPUS_DEFAULT
981	int
982	depends on X86_32
983	default   32 if  X86_BIGSMP
984	default    8 if  SMP
985	default    1 if !SMP
986
987config NR_CPUS_DEFAULT
988	int
989	depends on X86_64
990	default 8192 if  MAXSMP
991	default   64 if  SMP
992	default    1 if !SMP
993
994config NR_CPUS
995	int "Maximum number of CPUs" if SMP && !MAXSMP
996	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
997	default NR_CPUS_DEFAULT
998	help
999	  This allows you to specify the maximum number of CPUs which this
1000	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1001	  supported value is 8192, otherwise the maximum value is 512.  The
1002	  minimum value which makes sense is 2.
1003
1004	  This is purely to save memory: each supported CPU adds about 8KB
1005	  to the kernel image.
1006
1007config SCHED_CLUSTER
1008	bool "Cluster scheduler support"
1009	depends on SMP
1010	default y
1011	help
1012	  Cluster scheduler support improves the CPU scheduler's decision
1013	  making when dealing with machines that have clusters of CPUs.
1014	  Cluster usually means a couple of CPUs which are placed closely
1015	  by sharing mid-level caches, last-level cache tags or internal
1016	  busses.
1017
1018config SCHED_SMT
1019	def_bool y if SMP
1020
1021config SCHED_MC
1022	def_bool y
1023	prompt "Multi-core scheduler support"
1024	depends on SMP
1025	help
1026	  Multi-core scheduler support improves the CPU scheduler's decision
1027	  making when dealing with multi-core CPU chips at a cost of slightly
1028	  increased overhead in some places. If unsure say N here.
1029
1030config SCHED_MC_PRIO
1031	bool "CPU core priorities scheduler support"
1032	depends on SCHED_MC && CPU_SUP_INTEL
1033	select X86_INTEL_PSTATE
1034	select CPU_FREQ
1035	default y
1036	help
1037	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1038	  core ordering determined at manufacturing time, which allows
1039	  certain cores to reach higher turbo frequencies (when running
1040	  single threaded workloads) than others.
1041
1042	  Enabling this kernel feature teaches the scheduler about
1043	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1044	  scheduler's CPU selection logic accordingly, so that higher
1045	  overall system performance can be achieved.
1046
1047	  This feature will have no effect on CPUs without this feature.
1048
1049	  If unsure say Y here.
1050
1051config UP_LATE_INIT
1052	def_bool y
1053	depends on !SMP && X86_LOCAL_APIC
1054
1055config X86_UP_APIC
1056	bool "Local APIC support on uniprocessors" if !PCI_MSI
1057	default PCI_MSI
1058	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1059	help
1060	  A local APIC (Advanced Programmable Interrupt Controller) is an
1061	  integrated interrupt controller in the CPU. If you have a single-CPU
1062	  system which has a processor with a local APIC, you can say Y here to
1063	  enable and use it. If you say Y here even though your machine doesn't
1064	  have a local APIC, then the kernel will still run with no slowdown at
1065	  all. The local APIC supports CPU-generated self-interrupts (timer,
1066	  performance counters), and the NMI watchdog which detects hard
1067	  lockups.
1068
1069config X86_UP_IOAPIC
1070	bool "IO-APIC support on uniprocessors"
1071	depends on X86_UP_APIC
1072	help
1073	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1074	  SMP-capable replacement for PC-style interrupt controllers. Most
1075	  SMP systems and many recent uniprocessor systems have one.
1076
1077	  If you have a single-CPU system with an IO-APIC, you can say Y here
1078	  to use it. If you say Y here even though your machine doesn't have
1079	  an IO-APIC, then the kernel will still run with no slowdown at all.
1080
1081config X86_LOCAL_APIC
1082	def_bool y
1083	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1084	select IRQ_DOMAIN_HIERARCHY
1085	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1086
1087config X86_IO_APIC
1088	def_bool y
1089	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1090
1091config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1092	bool "Reroute for broken boot IRQs"
1093	depends on X86_IO_APIC
1094	help
1095	  This option enables a workaround that fixes a source of
1096	  spurious interrupts. This is recommended when threaded
1097	  interrupt handling is used on systems where the generation of
1098	  superfluous "boot interrupts" cannot be disabled.
1099
1100	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1101	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1102	  kernel does during interrupt handling). On chipsets where this
1103	  boot IRQ generation cannot be disabled, this workaround keeps
1104	  the original IRQ line masked so that only the equivalent "boot
1105	  IRQ" is delivered to the CPUs. The workaround also tells the
1106	  kernel to set up the IRQ handler on the boot IRQ line. In this
1107	  way only one interrupt is delivered to the kernel. Otherwise
1108	  the spurious second interrupt may cause the kernel to bring
1109	  down (vital) interrupt lines.
1110
1111	  Only affects "broken" chipsets. Interrupt sharing may be
1112	  increased on these systems.
1113
1114config X86_MCE
1115	bool "Machine Check / overheating reporting"
1116	select GENERIC_ALLOCATOR
1117	default y
1118	help
1119	  Machine Check support allows the processor to notify the
1120	  kernel if it detects a problem (e.g. overheating, data corruption).
1121	  The action the kernel takes depends on the severity of the problem,
1122	  ranging from warning messages to halting the machine.
1123
1124config X86_MCELOG_LEGACY
1125	bool "Support for deprecated /dev/mcelog character device"
1126	depends on X86_MCE
1127	help
1128	  Enable support for /dev/mcelog which is needed by the old mcelog
1129	  userspace logging daemon. Consider switching to the new generation
1130	  rasdaemon solution.
1131
1132config X86_MCE_INTEL
1133	def_bool y
1134	prompt "Intel MCE features"
1135	depends on X86_MCE && X86_LOCAL_APIC
1136	help
1137	   Additional support for intel specific MCE features such as
1138	   the thermal monitor.
1139
1140config X86_MCE_AMD
1141	def_bool y
1142	prompt "AMD MCE features"
1143	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1144	help
1145	   Additional support for AMD specific MCE features such as
1146	   the DRAM Error Threshold.
1147
1148config X86_ANCIENT_MCE
1149	bool "Support for old Pentium 5 / WinChip machine checks"
1150	depends on X86_32 && X86_MCE
1151	help
1152	  Include support for machine check handling on old Pentium 5 or WinChip
1153	  systems. These typically need to be enabled explicitly on the command
1154	  line.
1155
1156config X86_MCE_THRESHOLD
1157	depends on X86_MCE_AMD || X86_MCE_INTEL
1158	def_bool y
1159
1160config X86_MCE_INJECT
1161	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1162	tristate "Machine check injector support"
1163	help
1164	  Provide support for injecting machine checks for testing purposes.
1165	  If you don't know what a machine check is and you don't do kernel
1166	  QA it is safe to say n.
1167
1168source "arch/x86/events/Kconfig"
1169
1170config X86_LEGACY_VM86
1171	bool "Legacy VM86 support"
1172	depends on X86_32
1173	help
1174	  This option allows user programs to put the CPU into V8086
1175	  mode, which is an 80286-era approximation of 16-bit real mode.
1176
1177	  Some very old versions of X and/or vbetool require this option
1178	  for user mode setting.  Similarly, DOSEMU will use it if
1179	  available to accelerate real mode DOS programs.  However, any
1180	  recent version of DOSEMU, X, or vbetool should be fully
1181	  functional even without kernel VM86 support, as they will all
1182	  fall back to software emulation. Nevertheless, if you are using
1183	  a 16-bit DOS program where 16-bit performance matters, vm86
1184	  mode might be faster than emulation and you might want to
1185	  enable this option.
1186
1187	  Note that any app that works on a 64-bit kernel is unlikely to
1188	  need this option, as 64-bit kernels don't, and can't, support
1189	  V8086 mode. This option is also unrelated to 16-bit protected
1190	  mode and is not needed to run most 16-bit programs under Wine.
1191
1192	  Enabling this option increases the complexity of the kernel
1193	  and slows down exception handling a tiny bit.
1194
1195	  If unsure, say N here.
1196
1197config VM86
1198	bool
1199	default X86_LEGACY_VM86
1200
1201config X86_16BIT
1202	bool "Enable support for 16-bit segments" if EXPERT
1203	default y
1204	depends on MODIFY_LDT_SYSCALL
1205	help
1206	  This option is required by programs like Wine to run 16-bit
1207	  protected mode legacy code on x86 processors.  Disabling
1208	  this option saves about 300 bytes on i386, or around 6K text
1209	  plus 16K runtime memory on x86-64,
1210
1211config X86_ESPFIX32
1212	def_bool y
1213	depends on X86_16BIT && X86_32
1214
1215config X86_ESPFIX64
1216	def_bool y
1217	depends on X86_16BIT && X86_64
1218
1219config X86_VSYSCALL_EMULATION
1220	bool "Enable vsyscall emulation" if EXPERT
1221	default y
1222	depends on X86_64
1223	help
1224	 This enables emulation of the legacy vsyscall page.  Disabling
1225	 it is roughly equivalent to booting with vsyscall=none, except
1226	 that it will also disable the helpful warning if a program
1227	 tries to use a vsyscall.  With this option set to N, offending
1228	 programs will just segfault, citing addresses of the form
1229	 0xffffffffff600?00.
1230
1231	 This option is required by many programs built before 2013, and
1232	 care should be used even with newer programs if set to N.
1233
1234	 Disabling this option saves about 7K of kernel size and
1235	 possibly 4K of additional runtime pagetable memory.
1236
1237config X86_IOPL_IOPERM
1238	bool "IOPERM and IOPL Emulation"
1239	default y
1240	help
1241	  This enables the ioperm() and iopl() syscalls which are necessary
1242	  for legacy applications.
1243
1244	  Legacy IOPL support is an overbroad mechanism which allows user
1245	  space aside of accessing all 65536 I/O ports also to disable
1246	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1247	  capabilities and permission from potentially active security
1248	  modules.
1249
1250	  The emulation restricts the functionality of the syscall to
1251	  only allowing the full range I/O port access, but prevents the
1252	  ability to disable interrupts from user space which would be
1253	  granted if the hardware IOPL mechanism would be used.
1254
1255config TOSHIBA
1256	tristate "Toshiba Laptop support"
1257	depends on X86_32
1258	help
1259	  This adds a driver to safely access the System Management Mode of
1260	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1261	  not work on models with a Phoenix BIOS. The System Management Mode
1262	  is used to set the BIOS and power saving options on Toshiba portables.
1263
1264	  For information on utilities to make use of this driver see the
1265	  Toshiba Linux utilities web site at:
1266	  <http://www.buzzard.org.uk/toshiba/>.
1267
1268	  Say Y if you intend to run this kernel on a Toshiba portable.
1269	  Say N otherwise.
1270
1271config I8K
1272	tristate "Dell i8k legacy laptop support"
1273	depends on HWMON
1274	depends on PROC_FS
1275	select SENSORS_DELL_SMM
1276	help
1277	  This option enables legacy /proc/i8k userspace interface in hwmon
1278	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1279	  temperature and allows controlling fan speeds of Dell laptops via
1280	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1281	  it reports also power and hotkey status. For fan speed control is
1282	  needed userspace package i8kutils.
1283
1284	  Say Y if you intend to run this kernel on old Dell laptops or want to
1285	  use userspace package i8kutils.
1286	  Say N otherwise.
1287
1288config X86_REBOOTFIXUPS
1289	bool "Enable X86 board specific fixups for reboot"
1290	depends on X86_32
1291	help
1292	  This enables chipset and/or board specific fixups to be done
1293	  in order to get reboot to work correctly. This is only needed on
1294	  some combinations of hardware and BIOS. The symptom, for which
1295	  this config is intended, is when reboot ends with a stalled/hung
1296	  system.
1297
1298	  Currently, the only fixup is for the Geode machines using
1299	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1300
1301	  Say Y if you want to enable the fixup. Currently, it's safe to
1302	  enable this option even if you don't need it.
1303	  Say N otherwise.
1304
1305config MICROCODE
1306	bool "CPU microcode loading support"
1307	default y
1308	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1309	help
1310	  If you say Y here, you will be able to update the microcode on
1311	  Intel and AMD processors. The Intel support is for the IA32 family,
1312	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1313	  AMD support is for families 0x10 and later. You will obviously need
1314	  the actual microcode binary data itself which is not shipped with
1315	  the Linux kernel.
1316
1317	  The preferred method to load microcode from a detached initrd is described
1318	  in Documentation/x86/microcode.rst. For that you need to enable
1319	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1320	  initrd for microcode blobs.
1321
1322	  In addition, you can build the microcode into the kernel. For that you
1323	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1324	  config option.
1325
1326config MICROCODE_INTEL
1327	bool "Intel microcode loading support"
1328	depends on MICROCODE
1329	default MICROCODE
1330	help
1331	  This options enables microcode patch loading support for Intel
1332	  processors.
1333
1334	  For the current Intel microcode data package go to
1335	  <https://downloadcenter.intel.com> and search for
1336	  'Linux Processor Microcode Data File'.
1337
1338config MICROCODE_AMD
1339	bool "AMD microcode loading support"
1340	depends on MICROCODE
1341	help
1342	  If you select this option, microcode patch loading support for AMD
1343	  processors will be enabled.
1344
1345config MICROCODE_OLD_INTERFACE
1346	bool "Ancient loading interface (DEPRECATED)"
1347	default n
1348	depends on MICROCODE
1349	help
1350	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1351	  which was used by userspace tools like iucode_tool and microcode.ctl.
1352	  It is inadequate because it runs too late to be able to properly
1353	  load microcode on a machine and it needs special tools. Instead, you
1354	  should've switched to the early loading method with the initrd or
1355	  builtin microcode by now: Documentation/x86/microcode.rst
1356
1357config X86_MSR
1358	tristate "/dev/cpu/*/msr - Model-specific register support"
1359	help
1360	  This device gives privileged processes access to the x86
1361	  Model-Specific Registers (MSRs).  It is a character device with
1362	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1363	  MSR accesses are directed to a specific CPU on multi-processor
1364	  systems.
1365
1366config X86_CPUID
1367	tristate "/dev/cpu/*/cpuid - CPU information support"
1368	help
1369	  This device gives processes access to the x86 CPUID instruction to
1370	  be executed on a specific processor.  It is a character device
1371	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1372	  /dev/cpu/31/cpuid.
1373
1374choice
1375	prompt "High Memory Support"
1376	default HIGHMEM4G
1377	depends on X86_32
1378
1379config NOHIGHMEM
1380	bool "off"
1381	help
1382	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1383	  However, the address space of 32-bit x86 processors is only 4
1384	  Gigabytes large. That means that, if you have a large amount of
1385	  physical memory, not all of it can be "permanently mapped" by the
1386	  kernel. The physical memory that's not permanently mapped is called
1387	  "high memory".
1388
1389	  If you are compiling a kernel which will never run on a machine with
1390	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1391	  choice and suitable for most users). This will result in a "3GB/1GB"
1392	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1393	  space and the remaining part of the 4GB virtual memory space is used
1394	  by the kernel to permanently map as much physical memory as
1395	  possible.
1396
1397	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1398	  answer "4GB" here.
1399
1400	  If more than 4 Gigabytes is used then answer "64GB" here. This
1401	  selection turns Intel PAE (Physical Address Extension) mode on.
1402	  PAE implements 3-level paging on IA32 processors. PAE is fully
1403	  supported by Linux, PAE mode is implemented on all recent Intel
1404	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1405	  then the kernel will not boot on CPUs that don't support PAE!
1406
1407	  The actual amount of total physical memory will either be
1408	  auto detected or can be forced by using a kernel command line option
1409	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1410	  your boot loader (lilo or loadlin) about how to pass options to the
1411	  kernel at boot time.)
1412
1413	  If unsure, say "off".
1414
1415config HIGHMEM4G
1416	bool "4GB"
1417	help
1418	  Select this if you have a 32-bit processor and between 1 and 4
1419	  gigabytes of physical RAM.
1420
1421config HIGHMEM64G
1422	bool "64GB"
1423	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1424	select X86_PAE
1425	help
1426	  Select this if you have a 32-bit processor and more than 4
1427	  gigabytes of physical RAM.
1428
1429endchoice
1430
1431choice
1432	prompt "Memory split" if EXPERT
1433	default VMSPLIT_3G
1434	depends on X86_32
1435	help
1436	  Select the desired split between kernel and user memory.
1437
1438	  If the address range available to the kernel is less than the
1439	  physical memory installed, the remaining memory will be available
1440	  as "high memory". Accessing high memory is a little more costly
1441	  than low memory, as it needs to be mapped into the kernel first.
1442	  Note that increasing the kernel address space limits the range
1443	  available to user programs, making the address space there
1444	  tighter.  Selecting anything other than the default 3G/1G split
1445	  will also likely make your kernel incompatible with binary-only
1446	  kernel modules.
1447
1448	  If you are not absolutely sure what you are doing, leave this
1449	  option alone!
1450
1451	config VMSPLIT_3G
1452		bool "3G/1G user/kernel split"
1453	config VMSPLIT_3G_OPT
1454		depends on !X86_PAE
1455		bool "3G/1G user/kernel split (for full 1G low memory)"
1456	config VMSPLIT_2G
1457		bool "2G/2G user/kernel split"
1458	config VMSPLIT_2G_OPT
1459		depends on !X86_PAE
1460		bool "2G/2G user/kernel split (for full 2G low memory)"
1461	config VMSPLIT_1G
1462		bool "1G/3G user/kernel split"
1463endchoice
1464
1465config PAGE_OFFSET
1466	hex
1467	default 0xB0000000 if VMSPLIT_3G_OPT
1468	default 0x80000000 if VMSPLIT_2G
1469	default 0x78000000 if VMSPLIT_2G_OPT
1470	default 0x40000000 if VMSPLIT_1G
1471	default 0xC0000000
1472	depends on X86_32
1473
1474config HIGHMEM
1475	def_bool y
1476	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1477
1478config X86_PAE
1479	bool "PAE (Physical Address Extension) Support"
1480	depends on X86_32 && !HIGHMEM4G
1481	select PHYS_ADDR_T_64BIT
1482	select SWIOTLB
1483	help
1484	  PAE is required for NX support, and furthermore enables
1485	  larger swapspace support for non-overcommit purposes. It
1486	  has the cost of more pagetable lookup overhead, and also
1487	  consumes more pagetable space per process.
1488
1489config X86_5LEVEL
1490	bool "Enable 5-level page tables support"
1491	default y
1492	select DYNAMIC_MEMORY_LAYOUT
1493	select SPARSEMEM_VMEMMAP
1494	depends on X86_64
1495	help
1496	  5-level paging enables access to larger address space:
1497	  upto 128 PiB of virtual address space and 4 PiB of
1498	  physical address space.
1499
1500	  It will be supported by future Intel CPUs.
1501
1502	  A kernel with the option enabled can be booted on machines that
1503	  support 4- or 5-level paging.
1504
1505	  See Documentation/x86/x86_64/5level-paging.rst for more
1506	  information.
1507
1508	  Say N if unsure.
1509
1510config X86_DIRECT_GBPAGES
1511	def_bool y
1512	depends on X86_64
1513	help
1514	  Certain kernel features effectively disable kernel
1515	  linear 1 GB mappings (even if the CPU otherwise
1516	  supports them), so don't confuse the user by printing
1517	  that we have them enabled.
1518
1519config X86_CPA_STATISTICS
1520	bool "Enable statistic for Change Page Attribute"
1521	depends on DEBUG_FS
1522	help
1523	  Expose statistics about the Change Page Attribute mechanism, which
1524	  helps to determine the effectiveness of preserving large and huge
1525	  page mappings when mapping protections are changed.
1526
1527config X86_MEM_ENCRYPT
1528	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1529	select DYNAMIC_PHYSICAL_MASK
1530	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
1531	def_bool n
1532
1533config AMD_MEM_ENCRYPT
1534	bool "AMD Secure Memory Encryption (SME) support"
1535	depends on X86_64 && CPU_SUP_AMD
1536	select DMA_COHERENT_POOL
1537	select ARCH_USE_MEMREMAP_PROT
1538	select INSTRUCTION_DECODER
1539	select ARCH_HAS_CC_PLATFORM
1540	select X86_MEM_ENCRYPT
1541	help
1542	  Say yes to enable support for the encryption of system memory.
1543	  This requires an AMD processor that supports Secure Memory
1544	  Encryption (SME).
1545
1546config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1547	bool "Activate AMD Secure Memory Encryption (SME) by default"
1548	depends on AMD_MEM_ENCRYPT
1549	help
1550	  Say yes to have system memory encrypted by default if running on
1551	  an AMD processor that supports Secure Memory Encryption (SME).
1552
1553	  If set to Y, then the encryption of system memory can be
1554	  deactivated with the mem_encrypt=off command line option.
1555
1556	  If set to N, then the encryption of system memory can be
1557	  activated with the mem_encrypt=on command line option.
1558
1559# Common NUMA Features
1560config NUMA
1561	bool "NUMA Memory Allocation and Scheduler Support"
1562	depends on SMP
1563	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1564	default y if X86_BIGSMP
1565	help
1566	  Enable NUMA (Non-Uniform Memory Access) support.
1567
1568	  The kernel will try to allocate memory used by a CPU on the
1569	  local memory controller of the CPU and add some more
1570	  NUMA awareness to the kernel.
1571
1572	  For 64-bit this is recommended if the system is Intel Core i7
1573	  (or later), AMD Opteron, or EM64T NUMA.
1574
1575	  For 32-bit this is only needed if you boot a 32-bit
1576	  kernel on a 64-bit NUMA platform.
1577
1578	  Otherwise, you should say N.
1579
1580config AMD_NUMA
1581	def_bool y
1582	prompt "Old style AMD Opteron NUMA detection"
1583	depends on X86_64 && NUMA && PCI
1584	help
1585	  Enable AMD NUMA node topology detection.  You should say Y here if
1586	  you have a multi processor AMD system. This uses an old method to
1587	  read the NUMA configuration directly from the builtin Northbridge
1588	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1589	  which also takes priority if both are compiled in.
1590
1591config X86_64_ACPI_NUMA
1592	def_bool y
1593	prompt "ACPI NUMA detection"
1594	depends on X86_64 && NUMA && ACPI && PCI
1595	select ACPI_NUMA
1596	help
1597	  Enable ACPI SRAT based node topology detection.
1598
1599config NUMA_EMU
1600	bool "NUMA emulation"
1601	depends on NUMA
1602	help
1603	  Enable NUMA emulation. A flat machine will be split
1604	  into virtual nodes when booted with "numa=fake=N", where N is the
1605	  number of nodes. This is only useful for debugging.
1606
1607config NODES_SHIFT
1608	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1609	range 1 10
1610	default "10" if MAXSMP
1611	default "6" if X86_64
1612	default "3"
1613	depends on NUMA
1614	help
1615	  Specify the maximum number of NUMA Nodes available on the target
1616	  system.  Increases memory reserved to accommodate various tables.
1617
1618config ARCH_FLATMEM_ENABLE
1619	def_bool y
1620	depends on X86_32 && !NUMA
1621
1622config ARCH_SPARSEMEM_ENABLE
1623	def_bool y
1624	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1625	select SPARSEMEM_STATIC if X86_32
1626	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1627
1628config ARCH_SPARSEMEM_DEFAULT
1629	def_bool X86_64 || (NUMA && X86_32)
1630
1631config ARCH_SELECT_MEMORY_MODEL
1632	def_bool y
1633	depends on ARCH_SPARSEMEM_ENABLE
1634
1635config ARCH_MEMORY_PROBE
1636	bool "Enable sysfs memory/probe interface"
1637	depends on MEMORY_HOTPLUG
1638	help
1639	  This option enables a sysfs memory/probe interface for testing.
1640	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1641	  If you are unsure how to answer this question, answer N.
1642
1643config ARCH_PROC_KCORE_TEXT
1644	def_bool y
1645	depends on X86_64 && PROC_KCORE
1646
1647config ILLEGAL_POINTER_VALUE
1648	hex
1649	default 0 if X86_32
1650	default 0xdead000000000000 if X86_64
1651
1652config X86_PMEM_LEGACY_DEVICE
1653	bool
1654
1655config X86_PMEM_LEGACY
1656	tristate "Support non-standard NVDIMMs and ADR protected memory"
1657	depends on PHYS_ADDR_T_64BIT
1658	depends on BLK_DEV
1659	select X86_PMEM_LEGACY_DEVICE
1660	select NUMA_KEEP_MEMINFO if NUMA
1661	select LIBNVDIMM
1662	help
1663	  Treat memory marked using the non-standard e820 type of 12 as used
1664	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1665	  The kernel will offer these regions to the 'pmem' driver so
1666	  they can be used for persistent storage.
1667
1668	  Say Y if unsure.
1669
1670config HIGHPTE
1671	bool "Allocate 3rd-level pagetables from highmem"
1672	depends on HIGHMEM
1673	help
1674	  The VM uses one page table entry for each page of physical memory.
1675	  For systems with a lot of RAM, this can be wasteful of precious
1676	  low memory.  Setting this option will put user-space page table
1677	  entries in high memory.
1678
1679config X86_CHECK_BIOS_CORRUPTION
1680	bool "Check for low memory corruption"
1681	help
1682	  Periodically check for memory corruption in low memory, which
1683	  is suspected to be caused by BIOS.  Even when enabled in the
1684	  configuration, it is disabled at runtime.  Enable it by
1685	  setting "memory_corruption_check=1" on the kernel command
1686	  line.  By default it scans the low 64k of memory every 60
1687	  seconds; see the memory_corruption_check_size and
1688	  memory_corruption_check_period parameters in
1689	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1690
1691	  When enabled with the default parameters, this option has
1692	  almost no overhead, as it reserves a relatively small amount
1693	  of memory and scans it infrequently.  It both detects corruption
1694	  and prevents it from affecting the running system.
1695
1696	  It is, however, intended as a diagnostic tool; if repeatable
1697	  BIOS-originated corruption always affects the same memory,
1698	  you can use memmap= to prevent the kernel from using that
1699	  memory.
1700
1701config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1702	bool "Set the default setting of memory_corruption_check"
1703	depends on X86_CHECK_BIOS_CORRUPTION
1704	default y
1705	help
1706	  Set whether the default state of memory_corruption_check is
1707	  on or off.
1708
1709config MATH_EMULATION
1710	bool
1711	depends on MODIFY_LDT_SYSCALL
1712	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1713	help
1714	  Linux can emulate a math coprocessor (used for floating point
1715	  operations) if you don't have one. 486DX and Pentium processors have
1716	  a math coprocessor built in, 486SX and 386 do not, unless you added
1717	  a 487DX or 387, respectively. (The messages during boot time can
1718	  give you some hints here ["man dmesg"].) Everyone needs either a
1719	  coprocessor or this emulation.
1720
1721	  If you don't have a math coprocessor, you need to say Y here; if you
1722	  say Y here even though you have a coprocessor, the coprocessor will
1723	  be used nevertheless. (This behavior can be changed with the kernel
1724	  command line option "no387", which comes handy if your coprocessor
1725	  is broken. Try "man bootparam" or see the documentation of your boot
1726	  loader (lilo or loadlin) about how to pass options to the kernel at
1727	  boot time.) This means that it is a good idea to say Y here if you
1728	  intend to use this kernel on different machines.
1729
1730	  More information about the internals of the Linux math coprocessor
1731	  emulation can be found in <file:arch/x86/math-emu/README>.
1732
1733	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1734	  kernel, it won't hurt.
1735
1736config MTRR
1737	def_bool y
1738	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1739	help
1740	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1741	  the Memory Type Range Registers (MTRRs) may be used to control
1742	  processor access to memory ranges. This is most useful if you have
1743	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1744	  allows bus write transfers to be combined into a larger transfer
1745	  before bursting over the PCI/AGP bus. This can increase performance
1746	  of image write operations 2.5 times or more. Saying Y here creates a
1747	  /proc/mtrr file which may be used to manipulate your processor's
1748	  MTRRs. Typically the X server should use this.
1749
1750	  This code has a reasonably generic interface so that similar
1751	  control registers on other processors can be easily supported
1752	  as well:
1753
1754	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1755	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1756	  these, the ARRs are used to emulate the MTRRs.
1757	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1758	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1759	  write-combining. All of these processors are supported by this code
1760	  and it makes sense to say Y here if you have one of them.
1761
1762	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1763	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1764	  can lead to all sorts of problems, so it's good to say Y here.
1765
1766	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1767	  just add about 9 KB to your kernel.
1768
1769	  See <file:Documentation/x86/mtrr.rst> for more information.
1770
1771config MTRR_SANITIZER
1772	def_bool y
1773	prompt "MTRR cleanup support"
1774	depends on MTRR
1775	help
1776	  Convert MTRR layout from continuous to discrete, so X drivers can
1777	  add writeback entries.
1778
1779	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1780	  The largest mtrr entry size for a continuous block can be set with
1781	  mtrr_chunk_size.
1782
1783	  If unsure, say Y.
1784
1785config MTRR_SANITIZER_ENABLE_DEFAULT
1786	int "MTRR cleanup enable value (0-1)"
1787	range 0 1
1788	default "0"
1789	depends on MTRR_SANITIZER
1790	help
1791	  Enable mtrr cleanup default value
1792
1793config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1794	int "MTRR cleanup spare reg num (0-7)"
1795	range 0 7
1796	default "1"
1797	depends on MTRR_SANITIZER
1798	help
1799	  mtrr cleanup spare entries default, it can be changed via
1800	  mtrr_spare_reg_nr=N on the kernel command line.
1801
1802config X86_PAT
1803	def_bool y
1804	prompt "x86 PAT support" if EXPERT
1805	depends on MTRR
1806	help
1807	  Use PAT attributes to setup page level cache control.
1808
1809	  PATs are the modern equivalents of MTRRs and are much more
1810	  flexible than MTRRs.
1811
1812	  Say N here if you see bootup problems (boot crash, boot hang,
1813	  spontaneous reboots) or a non-working video driver.
1814
1815	  If unsure, say Y.
1816
1817config ARCH_USES_PG_UNCACHED
1818	def_bool y
1819	depends on X86_PAT
1820
1821config ARCH_RANDOM
1822	def_bool y
1823	prompt "x86 architectural random number generator" if EXPERT
1824	help
1825	  Enable the x86 architectural RDRAND instruction
1826	  (Intel Bull Mountain technology) to generate random numbers.
1827	  If supported, this is a high bandwidth, cryptographically
1828	  secure hardware random number generator.
1829
1830config X86_SMAP
1831	def_bool y
1832	prompt "Supervisor Mode Access Prevention" if EXPERT
1833	help
1834	  Supervisor Mode Access Prevention (SMAP) is a security
1835	  feature in newer Intel processors.  There is a small
1836	  performance cost if this enabled and turned on; there is
1837	  also a small increase in the kernel size if this is enabled.
1838
1839	  If unsure, say Y.
1840
1841config X86_UMIP
1842	def_bool y
1843	prompt "User Mode Instruction Prevention" if EXPERT
1844	help
1845	  User Mode Instruction Prevention (UMIP) is a security feature in
1846	  some x86 processors. If enabled, a general protection fault is
1847	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1848	  executed in user mode. These instructions unnecessarily expose
1849	  information about the hardware state.
1850
1851	  The vast majority of applications do not use these instructions.
1852	  For the very few that do, software emulation is provided in
1853	  specific cases in protected and virtual-8086 modes. Emulated
1854	  results are dummy.
1855
1856config X86_INTEL_MEMORY_PROTECTION_KEYS
1857	prompt "Memory Protection Keys"
1858	def_bool y
1859	# Note: only available in 64-bit mode
1860	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1861	select ARCH_USES_HIGH_VMA_FLAGS
1862	select ARCH_HAS_PKEYS
1863	help
1864	  Memory Protection Keys provides a mechanism for enforcing
1865	  page-based protections, but without requiring modification of the
1866	  page tables when an application changes protection domains.
1867
1868	  For details, see Documentation/core-api/protection-keys.rst
1869
1870	  If unsure, say y.
1871
1872choice
1873	prompt "TSX enable mode"
1874	depends on CPU_SUP_INTEL
1875	default X86_INTEL_TSX_MODE_OFF
1876	help
1877	  Intel's TSX (Transactional Synchronization Extensions) feature
1878	  allows to optimize locking protocols through lock elision which
1879	  can lead to a noticeable performance boost.
1880
1881	  On the other hand it has been shown that TSX can be exploited
1882	  to form side channel attacks (e.g. TAA) and chances are there
1883	  will be more of those attacks discovered in the future.
1884
1885	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1886	  might override this decision by tsx=on the command line parameter.
1887	  Even with TSX enabled, the kernel will attempt to enable the best
1888	  possible TAA mitigation setting depending on the microcode available
1889	  for the particular machine.
1890
1891	  This option allows to set the default tsx mode between tsx=on, =off
1892	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1893	  details.
1894
1895	  Say off if not sure, auto if TSX is in use but it should be used on safe
1896	  platforms or on if TSX is in use and the security aspect of tsx is not
1897	  relevant.
1898
1899config X86_INTEL_TSX_MODE_OFF
1900	bool "off"
1901	help
1902	  TSX is disabled if possible - equals to tsx=off command line parameter.
1903
1904config X86_INTEL_TSX_MODE_ON
1905	bool "on"
1906	help
1907	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1908	  line parameter.
1909
1910config X86_INTEL_TSX_MODE_AUTO
1911	bool "auto"
1912	help
1913	  TSX is enabled on TSX capable HW that is believed to be safe against
1914	  side channel attacks- equals the tsx=auto command line parameter.
1915endchoice
1916
1917config X86_SGX
1918	bool "Software Guard eXtensions (SGX)"
1919	depends on X86_64 && CPU_SUP_INTEL
1920	depends on CRYPTO=y
1921	depends on CRYPTO_SHA256=y
1922	select SRCU
1923	select MMU_NOTIFIER
1924	select NUMA_KEEP_MEMINFO if NUMA
1925	select XARRAY_MULTI
1926	help
1927	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1928	  that can be used by applications to set aside private regions of code
1929	  and data, referred to as enclaves. An enclave's private memory can
1930	  only be accessed by code running within the enclave. Accesses from
1931	  outside the enclave, including other enclaves, are disallowed by
1932	  hardware.
1933
1934	  If unsure, say N.
1935
1936config EFI
1937	bool "EFI runtime service support"
1938	depends on ACPI
1939	select UCS2_STRING
1940	select EFI_RUNTIME_WRAPPERS
1941	select ARCH_USE_MEMREMAP_PROT
1942	help
1943	  This enables the kernel to use EFI runtime services that are
1944	  available (such as the EFI variable services).
1945
1946	  This option is only useful on systems that have EFI firmware.
1947	  In addition, you should use the latest ELILO loader available
1948	  at <http://elilo.sourceforge.net> in order to take advantage
1949	  of EFI runtime services. However, even with this option, the
1950	  resultant kernel should continue to boot on existing non-EFI
1951	  platforms.
1952
1953config EFI_STUB
1954	bool "EFI stub support"
1955	depends on EFI && !X86_USE_3DNOW
1956	depends on $(cc-option,-mabi=ms) || X86_32
1957	select RELOCATABLE
1958	help
1959	  This kernel feature allows a bzImage to be loaded directly
1960	  by EFI firmware without the use of a bootloader.
1961
1962	  See Documentation/admin-guide/efi-stub.rst for more information.
1963
1964config EFI_MIXED
1965	bool "EFI mixed-mode support"
1966	depends on EFI_STUB && X86_64
1967	help
1968	   Enabling this feature allows a 64-bit kernel to be booted
1969	   on a 32-bit firmware, provided that your CPU supports 64-bit
1970	   mode.
1971
1972	   Note that it is not possible to boot a mixed-mode enabled
1973	   kernel via the EFI boot stub - a bootloader that supports
1974	   the EFI handover protocol must be used.
1975
1976	   If unsure, say N.
1977
1978source "kernel/Kconfig.hz"
1979
1980config KEXEC
1981	bool "kexec system call"
1982	select KEXEC_CORE
1983	help
1984	  kexec is a system call that implements the ability to shutdown your
1985	  current kernel, and to start another kernel.  It is like a reboot
1986	  but it is independent of the system firmware.   And like a reboot
1987	  you can start any kernel with it, not just Linux.
1988
1989	  The name comes from the similarity to the exec system call.
1990
1991	  It is an ongoing process to be certain the hardware in a machine
1992	  is properly shutdown, so do not be surprised if this code does not
1993	  initially work for you.  As of this writing the exact hardware
1994	  interface is strongly in flux, so no good recommendation can be
1995	  made.
1996
1997config KEXEC_FILE
1998	bool "kexec file based system call"
1999	select KEXEC_CORE
2000	select BUILD_BIN2C
2001	depends on X86_64
2002	depends on CRYPTO=y
2003	depends on CRYPTO_SHA256=y
2004	help
2005	  This is new version of kexec system call. This system call is
2006	  file based and takes file descriptors as system call argument
2007	  for kernel and initramfs as opposed to list of segments as
2008	  accepted by previous system call.
2009
2010config ARCH_HAS_KEXEC_PURGATORY
2011	def_bool KEXEC_FILE
2012
2013config KEXEC_SIG
2014	bool "Verify kernel signature during kexec_file_load() syscall"
2015	depends on KEXEC_FILE
2016	help
2017
2018	  This option makes the kexec_file_load() syscall check for a valid
2019	  signature of the kernel image.  The image can still be loaded without
2020	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2021	  there's a signature that we can check, then it must be valid.
2022
2023	  In addition to this option, you need to enable signature
2024	  verification for the corresponding kernel image type being
2025	  loaded in order for this to work.
2026
2027config KEXEC_SIG_FORCE
2028	bool "Require a valid signature in kexec_file_load() syscall"
2029	depends on KEXEC_SIG
2030	help
2031	  This option makes kernel signature verification mandatory for
2032	  the kexec_file_load() syscall.
2033
2034config KEXEC_BZIMAGE_VERIFY_SIG
2035	bool "Enable bzImage signature verification support"
2036	depends on KEXEC_SIG
2037	depends on SIGNED_PE_FILE_VERIFICATION
2038	select SYSTEM_TRUSTED_KEYRING
2039	help
2040	  Enable bzImage signature verification support.
2041
2042config CRASH_DUMP
2043	bool "kernel crash dumps"
2044	depends on X86_64 || (X86_32 && HIGHMEM)
2045	help
2046	  Generate crash dump after being started by kexec.
2047	  This should be normally only set in special crash dump kernels
2048	  which are loaded in the main kernel with kexec-tools into
2049	  a specially reserved region and then later executed after
2050	  a crash by kdump/kexec. The crash dump kernel must be compiled
2051	  to a memory address not used by the main kernel or BIOS using
2052	  PHYSICAL_START, or it must be built as a relocatable image
2053	  (CONFIG_RELOCATABLE=y).
2054	  For more details see Documentation/admin-guide/kdump/kdump.rst
2055
2056config KEXEC_JUMP
2057	bool "kexec jump"
2058	depends on KEXEC && HIBERNATION
2059	help
2060	  Jump between original kernel and kexeced kernel and invoke
2061	  code in physical address mode via KEXEC
2062
2063config PHYSICAL_START
2064	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2065	default "0x1000000"
2066	help
2067	  This gives the physical address where the kernel is loaded.
2068
2069	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2070	  bzImage will decompress itself to above physical address and
2071	  run from there. Otherwise, bzImage will run from the address where
2072	  it has been loaded by the boot loader and will ignore above physical
2073	  address.
2074
2075	  In normal kdump cases one does not have to set/change this option
2076	  as now bzImage can be compiled as a completely relocatable image
2077	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2078	  address. This option is mainly useful for the folks who don't want
2079	  to use a bzImage for capturing the crash dump and want to use a
2080	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2081	  to be specifically compiled to run from a specific memory area
2082	  (normally a reserved region) and this option comes handy.
2083
2084	  So if you are using bzImage for capturing the crash dump,
2085	  leave the value here unchanged to 0x1000000 and set
2086	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2087	  for capturing the crash dump change this value to start of
2088	  the reserved region.  In other words, it can be set based on
2089	  the "X" value as specified in the "crashkernel=YM@XM"
2090	  command line boot parameter passed to the panic-ed
2091	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2092	  for more details about crash dumps.
2093
2094	  Usage of bzImage for capturing the crash dump is recommended as
2095	  one does not have to build two kernels. Same kernel can be used
2096	  as production kernel and capture kernel. Above option should have
2097	  gone away after relocatable bzImage support is introduced. But it
2098	  is present because there are users out there who continue to use
2099	  vmlinux for dump capture. This option should go away down the
2100	  line.
2101
2102	  Don't change this unless you know what you are doing.
2103
2104config RELOCATABLE
2105	bool "Build a relocatable kernel"
2106	default y
2107	help
2108	  This builds a kernel image that retains relocation information
2109	  so it can be loaded someplace besides the default 1MB.
2110	  The relocations tend to make the kernel binary about 10% larger,
2111	  but are discarded at runtime.
2112
2113	  One use is for the kexec on panic case where the recovery kernel
2114	  must live at a different physical address than the primary
2115	  kernel.
2116
2117	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2118	  it has been loaded at and the compile time physical address
2119	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2120
2121config RANDOMIZE_BASE
2122	bool "Randomize the address of the kernel image (KASLR)"
2123	depends on RELOCATABLE
2124	default y
2125	help
2126	  In support of Kernel Address Space Layout Randomization (KASLR),
2127	  this randomizes the physical address at which the kernel image
2128	  is decompressed and the virtual address where the kernel
2129	  image is mapped, as a security feature that deters exploit
2130	  attempts relying on knowledge of the location of kernel
2131	  code internals.
2132
2133	  On 64-bit, the kernel physical and virtual addresses are
2134	  randomized separately. The physical address will be anywhere
2135	  between 16MB and the top of physical memory (up to 64TB). The
2136	  virtual address will be randomized from 16MB up to 1GB (9 bits
2137	  of entropy). Note that this also reduces the memory space
2138	  available to kernel modules from 1.5GB to 1GB.
2139
2140	  On 32-bit, the kernel physical and virtual addresses are
2141	  randomized together. They will be randomized from 16MB up to
2142	  512MB (8 bits of entropy).
2143
2144	  Entropy is generated using the RDRAND instruction if it is
2145	  supported. If RDTSC is supported, its value is mixed into
2146	  the entropy pool as well. If neither RDRAND nor RDTSC are
2147	  supported, then entropy is read from the i8254 timer. The
2148	  usable entropy is limited by the kernel being built using
2149	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2150	  minimum of 2MB. As a result, only 10 bits of entropy are
2151	  theoretically possible, but the implementations are further
2152	  limited due to memory layouts.
2153
2154	  If unsure, say Y.
2155
2156# Relocation on x86 needs some additional build support
2157config X86_NEED_RELOCS
2158	def_bool y
2159	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2160
2161config PHYSICAL_ALIGN
2162	hex "Alignment value to which kernel should be aligned"
2163	default "0x200000"
2164	range 0x2000 0x1000000 if X86_32
2165	range 0x200000 0x1000000 if X86_64
2166	help
2167	  This value puts the alignment restrictions on physical address
2168	  where kernel is loaded and run from. Kernel is compiled for an
2169	  address which meets above alignment restriction.
2170
2171	  If bootloader loads the kernel at a non-aligned address and
2172	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2173	  address aligned to above value and run from there.
2174
2175	  If bootloader loads the kernel at a non-aligned address and
2176	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2177	  load address and decompress itself to the address it has been
2178	  compiled for and run from there. The address for which kernel is
2179	  compiled already meets above alignment restrictions. Hence the
2180	  end result is that kernel runs from a physical address meeting
2181	  above alignment restrictions.
2182
2183	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2184	  this value must be a multiple of 0x200000.
2185
2186	  Don't change this unless you know what you are doing.
2187
2188config DYNAMIC_MEMORY_LAYOUT
2189	bool
2190	help
2191	  This option makes base addresses of vmalloc and vmemmap as well as
2192	  __PAGE_OFFSET movable during boot.
2193
2194config RANDOMIZE_MEMORY
2195	bool "Randomize the kernel memory sections"
2196	depends on X86_64
2197	depends on RANDOMIZE_BASE
2198	select DYNAMIC_MEMORY_LAYOUT
2199	default RANDOMIZE_BASE
2200	help
2201	   Randomizes the base virtual address of kernel memory sections
2202	   (physical memory mapping, vmalloc & vmemmap). This security feature
2203	   makes exploits relying on predictable memory locations less reliable.
2204
2205	   The order of allocations remains unchanged. Entropy is generated in
2206	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2207	   configuration have in average 30,000 different possible virtual
2208	   addresses for each memory section.
2209
2210	   If unsure, say Y.
2211
2212config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2213	hex "Physical memory mapping padding" if EXPERT
2214	depends on RANDOMIZE_MEMORY
2215	default "0xa" if MEMORY_HOTPLUG
2216	default "0x0"
2217	range 0x1 0x40 if MEMORY_HOTPLUG
2218	range 0x0 0x40
2219	help
2220	   Define the padding in terabytes added to the existing physical
2221	   memory size during kernel memory randomization. It is useful
2222	   for memory hotplug support but reduces the entropy available for
2223	   address randomization.
2224
2225	   If unsure, leave at the default value.
2226
2227config HOTPLUG_CPU
2228	def_bool y
2229	depends on SMP
2230
2231config BOOTPARAM_HOTPLUG_CPU0
2232	bool "Set default setting of cpu0_hotpluggable"
2233	depends on HOTPLUG_CPU
2234	help
2235	  Set whether default state of cpu0_hotpluggable is on or off.
2236
2237	  Say Y here to enable CPU0 hotplug by default. If this switch
2238	  is turned on, there is no need to give cpu0_hotplug kernel
2239	  parameter and the CPU0 hotplug feature is enabled by default.
2240
2241	  Please note: there are two known CPU0 dependencies if you want
2242	  to enable the CPU0 hotplug feature either by this switch or by
2243	  cpu0_hotplug kernel parameter.
2244
2245	  First, resume from hibernate or suspend always starts from CPU0.
2246	  So hibernate and suspend are prevented if CPU0 is offline.
2247
2248	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2249	  offline if any interrupt can not migrate out of CPU0. There may
2250	  be other CPU0 dependencies.
2251
2252	  Please make sure the dependencies are under your control before
2253	  you enable this feature.
2254
2255	  Say N if you don't want to enable CPU0 hotplug feature by default.
2256	  You still can enable the CPU0 hotplug feature at boot by kernel
2257	  parameter cpu0_hotplug.
2258
2259config DEBUG_HOTPLUG_CPU0
2260	def_bool n
2261	prompt "Debug CPU0 hotplug"
2262	depends on HOTPLUG_CPU
2263	help
2264	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2265	  soon as possible and boots up userspace with CPU0 offlined. User
2266	  can online CPU0 back after boot time.
2267
2268	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2269	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2270	  compilation or giving cpu0_hotplug kernel parameter at boot.
2271
2272	  If unsure, say N.
2273
2274config COMPAT_VDSO
2275	def_bool n
2276	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2277	depends on COMPAT_32
2278	help
2279	  Certain buggy versions of glibc will crash if they are
2280	  presented with a 32-bit vDSO that is not mapped at the address
2281	  indicated in its segment table.
2282
2283	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2284	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2285	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2286	  the only released version with the bug, but OpenSUSE 9
2287	  contains a buggy "glibc 2.3.2".
2288
2289	  The symptom of the bug is that everything crashes on startup, saying:
2290	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2291
2292	  Saying Y here changes the default value of the vdso32 boot
2293	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2294	  This works around the glibc bug but hurts performance.
2295
2296	  If unsure, say N: if you are compiling your own kernel, you
2297	  are unlikely to be using a buggy version of glibc.
2298
2299choice
2300	prompt "vsyscall table for legacy applications"
2301	depends on X86_64
2302	default LEGACY_VSYSCALL_XONLY
2303	help
2304	  Legacy user code that does not know how to find the vDSO expects
2305	  to be able to issue three syscalls by calling fixed addresses in
2306	  kernel space. Since this location is not randomized with ASLR,
2307	  it can be used to assist security vulnerability exploitation.
2308
2309	  This setting can be changed at boot time via the kernel command
2310	  line parameter vsyscall=[emulate|xonly|none].
2311
2312	  On a system with recent enough glibc (2.14 or newer) and no
2313	  static binaries, you can say None without a performance penalty
2314	  to improve security.
2315
2316	  If unsure, select "Emulate execution only".
2317
2318	config LEGACY_VSYSCALL_EMULATE
2319		bool "Full emulation"
2320		help
2321		  The kernel traps and emulates calls into the fixed vsyscall
2322		  address mapping. This makes the mapping non-executable, but
2323		  it still contains readable known contents, which could be
2324		  used in certain rare security vulnerability exploits. This
2325		  configuration is recommended when using legacy userspace
2326		  that still uses vsyscalls along with legacy binary
2327		  instrumentation tools that require code to be readable.
2328
2329		  An example of this type of legacy userspace is running
2330		  Pin on an old binary that still uses vsyscalls.
2331
2332	config LEGACY_VSYSCALL_XONLY
2333		bool "Emulate execution only"
2334		help
2335		  The kernel traps and emulates calls into the fixed vsyscall
2336		  address mapping and does not allow reads.  This
2337		  configuration is recommended when userspace might use the
2338		  legacy vsyscall area but support for legacy binary
2339		  instrumentation of legacy code is not needed.  It mitigates
2340		  certain uses of the vsyscall area as an ASLR-bypassing
2341		  buffer.
2342
2343	config LEGACY_VSYSCALL_NONE
2344		bool "None"
2345		help
2346		  There will be no vsyscall mapping at all. This will
2347		  eliminate any risk of ASLR bypass due to the vsyscall
2348		  fixed address mapping. Attempts to use the vsyscalls
2349		  will be reported to dmesg, so that either old or
2350		  malicious userspace programs can be identified.
2351
2352endchoice
2353
2354config CMDLINE_BOOL
2355	bool "Built-in kernel command line"
2356	help
2357	  Allow for specifying boot arguments to the kernel at
2358	  build time.  On some systems (e.g. embedded ones), it is
2359	  necessary or convenient to provide some or all of the
2360	  kernel boot arguments with the kernel itself (that is,
2361	  to not rely on the boot loader to provide them.)
2362
2363	  To compile command line arguments into the kernel,
2364	  set this option to 'Y', then fill in the
2365	  boot arguments in CONFIG_CMDLINE.
2366
2367	  Systems with fully functional boot loaders (i.e. non-embedded)
2368	  should leave this option set to 'N'.
2369
2370config CMDLINE
2371	string "Built-in kernel command string"
2372	depends on CMDLINE_BOOL
2373	default ""
2374	help
2375	  Enter arguments here that should be compiled into the kernel
2376	  image and used at boot time.  If the boot loader provides a
2377	  command line at boot time, it is appended to this string to
2378	  form the full kernel command line, when the system boots.
2379
2380	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2381	  change this behavior.
2382
2383	  In most cases, the command line (whether built-in or provided
2384	  by the boot loader) should specify the device for the root
2385	  file system.
2386
2387config CMDLINE_OVERRIDE
2388	bool "Built-in command line overrides boot loader arguments"
2389	depends on CMDLINE_BOOL && CMDLINE != ""
2390	help
2391	  Set this option to 'Y' to have the kernel ignore the boot loader
2392	  command line, and use ONLY the built-in command line.
2393
2394	  This is used to work around broken boot loaders.  This should
2395	  be set to 'N' under normal conditions.
2396
2397config MODIFY_LDT_SYSCALL
2398	bool "Enable the LDT (local descriptor table)" if EXPERT
2399	default y
2400	help
2401	  Linux can allow user programs to install a per-process x86
2402	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2403	  call.  This is required to run 16-bit or segmented code such as
2404	  DOSEMU or some Wine programs.  It is also used by some very old
2405	  threading libraries.
2406
2407	  Enabling this feature adds a small amount of overhead to
2408	  context switches and increases the low-level kernel attack
2409	  surface.  Disabling it removes the modify_ldt(2) system call.
2410
2411	  Saying 'N' here may make sense for embedded or server kernels.
2412
2413config STRICT_SIGALTSTACK_SIZE
2414	bool "Enforce strict size checking for sigaltstack"
2415	depends on DYNAMIC_SIGFRAME
2416	help
2417	  For historical reasons MINSIGSTKSZ is a constant which became
2418	  already too small with AVX512 support. Add a mechanism to
2419	  enforce strict checking of the sigaltstack size against the
2420	  real size of the FPU frame. This option enables the check
2421	  by default. It can also be controlled via the kernel command
2422	  line option 'strict_sas_size' independent of this config
2423	  switch. Enabling it might break existing applications which
2424	  allocate a too small sigaltstack but 'work' because they
2425	  never get a signal delivered.
2426
2427	  Say 'N' unless you want to really enforce this check.
2428
2429source "kernel/livepatch/Kconfig"
2430
2431endmenu
2432
2433config ARCH_HAS_ADD_PAGES
2434	def_bool y
2435	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2436
2437config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2438	def_bool y
2439
2440config USE_PERCPU_NUMA_NODE_ID
2441	def_bool y
2442	depends on NUMA
2443
2444menu "Power management and ACPI options"
2445
2446config ARCH_HIBERNATION_HEADER
2447	def_bool y
2448	depends on HIBERNATION
2449
2450source "kernel/power/Kconfig"
2451
2452source "drivers/acpi/Kconfig"
2453
2454config X86_APM_BOOT
2455	def_bool y
2456	depends on APM
2457
2458menuconfig APM
2459	tristate "APM (Advanced Power Management) BIOS support"
2460	depends on X86_32 && PM_SLEEP
2461	help
2462	  APM is a BIOS specification for saving power using several different
2463	  techniques. This is mostly useful for battery powered laptops with
2464	  APM compliant BIOSes. If you say Y here, the system time will be
2465	  reset after a RESUME operation, the /proc/apm device will provide
2466	  battery status information, and user-space programs will receive
2467	  notification of APM "events" (e.g. battery status change).
2468
2469	  If you select "Y" here, you can disable actual use of the APM
2470	  BIOS by passing the "apm=off" option to the kernel at boot time.
2471
2472	  Note that the APM support is almost completely disabled for
2473	  machines with more than one CPU.
2474
2475	  In order to use APM, you will need supporting software. For location
2476	  and more information, read <file:Documentation/power/apm-acpi.rst>
2477	  and the Battery Powered Linux mini-HOWTO, available from
2478	  <http://www.tldp.org/docs.html#howto>.
2479
2480	  This driver does not spin down disk drives (see the hdparm(8)
2481	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2482	  VESA-compliant "green" monitors.
2483
2484	  This driver does not support the TI 4000M TravelMate and the ACER
2485	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2486	  desktop machines also don't have compliant BIOSes, and this driver
2487	  may cause those machines to panic during the boot phase.
2488
2489	  Generally, if you don't have a battery in your machine, there isn't
2490	  much point in using this driver and you should say N. If you get
2491	  random kernel OOPSes or reboots that don't seem to be related to
2492	  anything, try disabling/enabling this option (or disabling/enabling
2493	  APM in your BIOS).
2494
2495	  Some other things you should try when experiencing seemingly random,
2496	  "weird" problems:
2497
2498	  1) make sure that you have enough swap space and that it is
2499	  enabled.
2500	  2) pass the "no-hlt" option to the kernel
2501	  3) switch on floating point emulation in the kernel and pass
2502	  the "no387" option to the kernel
2503	  4) pass the "floppy=nodma" option to the kernel
2504	  5) pass the "mem=4M" option to the kernel (thereby disabling
2505	  all but the first 4 MB of RAM)
2506	  6) make sure that the CPU is not over clocked.
2507	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2508	  8) disable the cache from your BIOS settings
2509	  9) install a fan for the video card or exchange video RAM
2510	  10) install a better fan for the CPU
2511	  11) exchange RAM chips
2512	  12) exchange the motherboard.
2513
2514	  To compile this driver as a module, choose M here: the
2515	  module will be called apm.
2516
2517if APM
2518
2519config APM_IGNORE_USER_SUSPEND
2520	bool "Ignore USER SUSPEND"
2521	help
2522	  This option will ignore USER SUSPEND requests. On machines with a
2523	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2524	  series notebooks, it is necessary to say Y because of a BIOS bug.
2525
2526config APM_DO_ENABLE
2527	bool "Enable PM at boot time"
2528	help
2529	  Enable APM features at boot time. From page 36 of the APM BIOS
2530	  specification: "When disabled, the APM BIOS does not automatically
2531	  power manage devices, enter the Standby State, enter the Suspend
2532	  State, or take power saving steps in response to CPU Idle calls."
2533	  This driver will make CPU Idle calls when Linux is idle (unless this
2534	  feature is turned off -- see "Do CPU IDLE calls", below). This
2535	  should always save battery power, but more complicated APM features
2536	  will be dependent on your BIOS implementation. You may need to turn
2537	  this option off if your computer hangs at boot time when using APM
2538	  support, or if it beeps continuously instead of suspending. Turn
2539	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2540	  T400CDT. This is off by default since most machines do fine without
2541	  this feature.
2542
2543config APM_CPU_IDLE
2544	depends on CPU_IDLE
2545	bool "Make CPU Idle calls when idle"
2546	help
2547	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2548	  On some machines, this can activate improved power savings, such as
2549	  a slowed CPU clock rate, when the machine is idle. These idle calls
2550	  are made after the idle loop has run for some length of time (e.g.,
2551	  333 mS). On some machines, this will cause a hang at boot time or
2552	  whenever the CPU becomes idle. (On machines with more than one CPU,
2553	  this option does nothing.)
2554
2555config APM_DISPLAY_BLANK
2556	bool "Enable console blanking using APM"
2557	help
2558	  Enable console blanking using the APM. Some laptops can use this to
2559	  turn off the LCD backlight when the screen blanker of the Linux
2560	  virtual console blanks the screen. Note that this is only used by
2561	  the virtual console screen blanker, and won't turn off the backlight
2562	  when using the X Window system. This also doesn't have anything to
2563	  do with your VESA-compliant power-saving monitor. Further, this
2564	  option doesn't work for all laptops -- it might not turn off your
2565	  backlight at all, or it might print a lot of errors to the console,
2566	  especially if you are using gpm.
2567
2568config APM_ALLOW_INTS
2569	bool "Allow interrupts during APM BIOS calls"
2570	help
2571	  Normally we disable external interrupts while we are making calls to
2572	  the APM BIOS as a measure to lessen the effects of a badly behaving
2573	  BIOS implementation.  The BIOS should reenable interrupts if it
2574	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2575	  many of the newer IBM Thinkpads.  If you experience hangs when you
2576	  suspend, try setting this to Y.  Otherwise, say N.
2577
2578endif # APM
2579
2580source "drivers/cpufreq/Kconfig"
2581
2582source "drivers/cpuidle/Kconfig"
2583
2584source "drivers/idle/Kconfig"
2585
2586endmenu
2587
2588
2589menu "Bus options (PCI etc.)"
2590
2591choice
2592	prompt "PCI access mode"
2593	depends on X86_32 && PCI
2594	default PCI_GOANY
2595	help
2596	  On PCI systems, the BIOS can be used to detect the PCI devices and
2597	  determine their configuration. However, some old PCI motherboards
2598	  have BIOS bugs and may crash if this is done. Also, some embedded
2599	  PCI-based systems don't have any BIOS at all. Linux can also try to
2600	  detect the PCI hardware directly without using the BIOS.
2601
2602	  With this option, you can specify how Linux should detect the
2603	  PCI devices. If you choose "BIOS", the BIOS will be used,
2604	  if you choose "Direct", the BIOS won't be used, and if you
2605	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2606	  If you choose "Any", the kernel will try MMCONFIG, then the
2607	  direct access method and falls back to the BIOS if that doesn't
2608	  work. If unsure, go with the default, which is "Any".
2609
2610config PCI_GOBIOS
2611	bool "BIOS"
2612
2613config PCI_GOMMCONFIG
2614	bool "MMConfig"
2615
2616config PCI_GODIRECT
2617	bool "Direct"
2618
2619config PCI_GOOLPC
2620	bool "OLPC XO-1"
2621	depends on OLPC
2622
2623config PCI_GOANY
2624	bool "Any"
2625
2626endchoice
2627
2628config PCI_BIOS
2629	def_bool y
2630	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2631
2632# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2633config PCI_DIRECT
2634	def_bool y
2635	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2636
2637config PCI_MMCONFIG
2638	bool "Support mmconfig PCI config space access" if X86_64
2639	default y
2640	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2641	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2642
2643config PCI_OLPC
2644	def_bool y
2645	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2646
2647config PCI_XEN
2648	def_bool y
2649	depends on PCI && XEN
2650
2651config MMCONF_FAM10H
2652	def_bool y
2653	depends on X86_64 && PCI_MMCONFIG && ACPI
2654
2655config PCI_CNB20LE_QUIRK
2656	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2657	depends on PCI
2658	help
2659	  Read the PCI windows out of the CNB20LE host bridge. This allows
2660	  PCI hotplug to work on systems with the CNB20LE chipset which do
2661	  not have ACPI.
2662
2663	  There's no public spec for this chipset, and this functionality
2664	  is known to be incomplete.
2665
2666	  You should say N unless you know you need this.
2667
2668config ISA_BUS
2669	bool "ISA bus support on modern systems" if EXPERT
2670	help
2671	  Expose ISA bus device drivers and options available for selection and
2672	  configuration. Enable this option if your target machine has an ISA
2673	  bus. ISA is an older system, displaced by PCI and newer bus
2674	  architectures -- if your target machine is modern, it probably does
2675	  not have an ISA bus.
2676
2677	  If unsure, say N.
2678
2679# x86_64 have no ISA slots, but can have ISA-style DMA.
2680config ISA_DMA_API
2681	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2682	default y
2683	help
2684	  Enables ISA-style DMA support for devices requiring such controllers.
2685	  If unsure, say Y.
2686
2687if X86_32
2688
2689config ISA
2690	bool "ISA support"
2691	help
2692	  Find out whether you have ISA slots on your motherboard.  ISA is the
2693	  name of a bus system, i.e. the way the CPU talks to the other stuff
2694	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2695	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2696	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2697
2698config SCx200
2699	tristate "NatSemi SCx200 support"
2700	help
2701	  This provides basic support for National Semiconductor's
2702	  (now AMD's) Geode processors.  The driver probes for the
2703	  PCI-IDs of several on-chip devices, so its a good dependency
2704	  for other scx200_* drivers.
2705
2706	  If compiled as a module, the driver is named scx200.
2707
2708config SCx200HR_TIMER
2709	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2710	depends on SCx200
2711	default y
2712	help
2713	  This driver provides a clocksource built upon the on-chip
2714	  27MHz high-resolution timer.  Its also a workaround for
2715	  NSC Geode SC-1100's buggy TSC, which loses time when the
2716	  processor goes idle (as is done by the scheduler).  The
2717	  other workaround is idle=poll boot option.
2718
2719config OLPC
2720	bool "One Laptop Per Child support"
2721	depends on !X86_PAE
2722	select GPIOLIB
2723	select OF
2724	select OF_PROMTREE
2725	select IRQ_DOMAIN
2726	select OLPC_EC
2727	help
2728	  Add support for detecting the unique features of the OLPC
2729	  XO hardware.
2730
2731config OLPC_XO1_PM
2732	bool "OLPC XO-1 Power Management"
2733	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2734	help
2735	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2736
2737config OLPC_XO1_RTC
2738	bool "OLPC XO-1 Real Time Clock"
2739	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2740	help
2741	  Add support for the XO-1 real time clock, which can be used as a
2742	  programmable wakeup source.
2743
2744config OLPC_XO1_SCI
2745	bool "OLPC XO-1 SCI extras"
2746	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2747	depends on INPUT=y
2748	select POWER_SUPPLY
2749	help
2750	  Add support for SCI-based features of the OLPC XO-1 laptop:
2751	   - EC-driven system wakeups
2752	   - Power button
2753	   - Ebook switch
2754	   - Lid switch
2755	   - AC adapter status updates
2756	   - Battery status updates
2757
2758config OLPC_XO15_SCI
2759	bool "OLPC XO-1.5 SCI extras"
2760	depends on OLPC && ACPI
2761	select POWER_SUPPLY
2762	help
2763	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2764	   - EC-driven system wakeups
2765	   - AC adapter status updates
2766	   - Battery status updates
2767
2768config ALIX
2769	bool "PCEngines ALIX System Support (LED setup)"
2770	select GPIOLIB
2771	help
2772	  This option enables system support for the PCEngines ALIX.
2773	  At present this just sets up LEDs for GPIO control on
2774	  ALIX2/3/6 boards.  However, other system specific setup should
2775	  get added here.
2776
2777	  Note: You must still enable the drivers for GPIO and LED support
2778	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2779
2780	  Note: You have to set alix.force=1 for boards with Award BIOS.
2781
2782config NET5501
2783	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2784	select GPIOLIB
2785	help
2786	  This option enables system support for the Soekris Engineering net5501.
2787
2788config GEOS
2789	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2790	select GPIOLIB
2791	depends on DMI
2792	help
2793	  This option enables system support for the Traverse Technologies GEOS.
2794
2795config TS5500
2796	bool "Technologic Systems TS-5500 platform support"
2797	depends on MELAN
2798	select CHECK_SIGNATURE
2799	select NEW_LEDS
2800	select LEDS_CLASS
2801	help
2802	  This option enables system support for the Technologic Systems TS-5500.
2803
2804endif # X86_32
2805
2806config AMD_NB
2807	def_bool y
2808	depends on CPU_SUP_AMD && PCI
2809
2810endmenu
2811
2812
2813menu "Binary Emulations"
2814
2815config IA32_EMULATION
2816	bool "IA32 Emulation"
2817	depends on X86_64
2818	select ARCH_WANT_OLD_COMPAT_IPC
2819	select BINFMT_ELF
2820	select COMPAT_OLD_SIGACTION
2821	help
2822	  Include code to run legacy 32-bit programs under a
2823	  64-bit kernel. You should likely turn this on, unless you're
2824	  100% sure that you don't have any 32-bit programs left.
2825
2826config IA32_AOUT
2827	tristate "IA32 a.out support"
2828	depends on IA32_EMULATION
2829	depends on BROKEN
2830	help
2831	  Support old a.out binaries in the 32bit emulation.
2832
2833config X86_X32
2834	bool "x32 ABI for 64-bit mode"
2835	depends on X86_64
2836	help
2837	  Include code to run binaries for the x32 native 32-bit ABI
2838	  for 64-bit processors.  An x32 process gets access to the
2839	  full 64-bit register file and wide data path while leaving
2840	  pointers at 32 bits for smaller memory footprint.
2841
2842	  You will need a recent binutils (2.22 or later) with
2843	  elf32_x86_64 support enabled to compile a kernel with this
2844	  option set.
2845
2846config COMPAT_32
2847	def_bool y
2848	depends on IA32_EMULATION || X86_32
2849	select HAVE_UID16
2850	select OLD_SIGSUSPEND3
2851
2852config COMPAT
2853	def_bool y
2854	depends on IA32_EMULATION || X86_X32
2855
2856if COMPAT
2857config COMPAT_FOR_U64_ALIGNMENT
2858	def_bool y
2859
2860config SYSVIPC_COMPAT
2861	def_bool y
2862	depends on SYSVIPC
2863endif
2864
2865endmenu
2866
2867
2868config HAVE_ATOMIC_IOMAP
2869	def_bool y
2870	depends on X86_32
2871
2872source "arch/x86/kvm/Kconfig"
2873
2874source "arch/x86/Kconfig.assembler"
2875