xref: /openbmc/linux/arch/x86/Kconfig (revision cb325ddd)
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
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_PAGE_TABLE_CHECK	if X86_64
108	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
109	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
110	select ARCH_SUPPORTS_LTO_CLANG
111	select ARCH_SUPPORTS_LTO_CLANG_THIN
112	select ARCH_USE_BUILTIN_BSWAP
113	select ARCH_USE_MEMTEST
114	select ARCH_USE_QUEUED_RWLOCKS
115	select ARCH_USE_QUEUED_SPINLOCKS
116	select ARCH_USE_SYM_ANNOTATIONS
117	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
118	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
119	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
120	select ARCH_WANTS_NO_INSTR
121	select ARCH_WANT_GENERAL_HUGETLB
122	select ARCH_WANT_HUGE_PMD_SHARE
123	select ARCH_WANT_LD_ORPHAN_WARN
124	select ARCH_WANTS_THP_SWAP		if X86_64
125	select ARCH_HAS_PARANOID_L1D_FLUSH
126	select BUILDTIME_TABLE_SORT
127	select CLKEVT_I8253
128	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
129	select CLOCKSOURCE_WATCHDOG
130	select DCACHE_WORD_ACCESS
131	select DYNAMIC_SIGFRAME
132	select EDAC_ATOMIC_SCRUB
133	select EDAC_SUPPORT
134	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
135	select GENERIC_CLOCKEVENTS_MIN_ADJUST
136	select GENERIC_CMOS_UPDATE
137	select GENERIC_CPU_AUTOPROBE
138	select GENERIC_CPU_VULNERABILITIES
139	select GENERIC_EARLY_IOREMAP
140	select GENERIC_ENTRY
141	select GENERIC_IOMAP
142	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
143	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
144	select GENERIC_IRQ_MIGRATION		if SMP
145	select GENERIC_IRQ_PROBE
146	select GENERIC_IRQ_RESERVATION_MODE
147	select GENERIC_IRQ_SHOW
148	select GENERIC_PENDING_IRQ		if SMP
149	select GENERIC_PTDUMP
150	select GENERIC_SMP_IDLE_THREAD
151	select GENERIC_TIME_VSYSCALL
152	select GENERIC_GETTIMEOFDAY
153	select GENERIC_VDSO_TIME_NS
154	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
155	select HARDIRQS_SW_RESEND
156	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
157	select HAVE_ACPI_APEI			if ACPI
158	select HAVE_ACPI_APEI_NMI		if ACPI
159	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
160	select HAVE_ARCH_AUDITSYSCALL
161	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
162	select HAVE_ARCH_JUMP_LABEL
163	select HAVE_ARCH_JUMP_LABEL_RELATIVE
164	select HAVE_ARCH_KASAN			if X86_64
165	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
166	select HAVE_ARCH_KFENCE
167	select HAVE_ARCH_KGDB
168	select HAVE_ARCH_MMAP_RND_BITS		if MMU
169	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
170	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
171	select HAVE_ARCH_PREL32_RELOCATIONS
172	select HAVE_ARCH_SECCOMP_FILTER
173	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
174	select HAVE_ARCH_STACKLEAK
175	select HAVE_ARCH_TRACEHOOK
176	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
177	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
178	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
179	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
180	select HAVE_ARCH_VMAP_STACK		if X86_64
181	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
182	select HAVE_ARCH_WITHIN_STACK_FRAMES
183	select HAVE_ASM_MODVERSIONS
184	select HAVE_CMPXCHG_DOUBLE
185	select HAVE_CMPXCHG_LOCAL
186	select HAVE_CONTEXT_TRACKING		if X86_64
187	select HAVE_CONTEXT_TRACKING_OFFSTACK	if HAVE_CONTEXT_TRACKING
188	select HAVE_C_RECORDMCOUNT
189	select HAVE_OBJTOOL_MCOUNT		if STACK_VALIDATION
190	select HAVE_BUILDTIME_MCOUNT_SORT
191	select HAVE_DEBUG_KMEMLEAK
192	select HAVE_DMA_CONTIGUOUS
193	select HAVE_DYNAMIC_FTRACE
194	select HAVE_DYNAMIC_FTRACE_WITH_REGS
195	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
196	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
197	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
198	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
199	select HAVE_EBPF_JIT
200	select HAVE_EFFICIENT_UNALIGNED_ACCESS
201	select HAVE_EISA
202	select HAVE_EXIT_THREAD
203	select HAVE_FAST_GUP
204	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
205	select HAVE_FTRACE_MCOUNT_RECORD
206	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
207	select HAVE_FUNCTION_TRACER
208	select HAVE_GCC_PLUGINS
209	select HAVE_HW_BREAKPOINT
210	select HAVE_IOREMAP_PROT
211	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
212	select HAVE_IRQ_TIME_ACCOUNTING
213	select HAVE_KERNEL_BZIP2
214	select HAVE_KERNEL_GZIP
215	select HAVE_KERNEL_LZ4
216	select HAVE_KERNEL_LZMA
217	select HAVE_KERNEL_LZO
218	select HAVE_KERNEL_XZ
219	select HAVE_KERNEL_ZSTD
220	select HAVE_KPROBES
221	select HAVE_KPROBES_ON_FTRACE
222	select HAVE_FUNCTION_ERROR_INJECTION
223	select HAVE_KRETPROBES
224	select HAVE_KVM
225	select HAVE_LIVEPATCH			if X86_64
226	select HAVE_MIXED_BREAKPOINTS_REGS
227	select HAVE_MOD_ARCH_SPECIFIC
228	select HAVE_MOVE_PMD
229	select HAVE_MOVE_PUD
230	select HAVE_NMI
231	select HAVE_OPTPROBES
232	select HAVE_PCSPKR_PLATFORM
233	select HAVE_PERF_EVENTS
234	select HAVE_PERF_EVENTS_NMI
235	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
236	select HAVE_PCI
237	select HAVE_PERF_REGS
238	select HAVE_PERF_USER_STACK_DUMP
239	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
240	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
241	select HAVE_REGS_AND_STACK_ACCESS_API
242	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
243	select HAVE_FUNCTION_ARG_ACCESS_API
244	select HAVE_SETUP_PER_CPU_AREA
245	select HAVE_SOFTIRQ_ON_OWN_STACK
246	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
247	select HAVE_STACK_VALIDATION		if X86_64
248	select HAVE_STATIC_CALL
249	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
250	select HAVE_PREEMPT_DYNAMIC
251	select HAVE_RSEQ
252	select HAVE_SYSCALL_TRACEPOINTS
253	select HAVE_UNSTABLE_SCHED_CLOCK
254	select HAVE_USER_RETURN_NOTIFIER
255	select HAVE_GENERIC_VDSO
256	select HOTPLUG_SMT			if SMP
257	select IRQ_FORCED_THREADING
258	select NEED_PER_CPU_EMBED_FIRST_CHUNK
259	select NEED_PER_CPU_PAGE_FIRST_CHUNK
260	select NEED_SG_DMA_LENGTH
261	select PCI_DOMAINS			if PCI
262	select PCI_LOCKLESS_CONFIG		if PCI
263	select PERF_EVENTS
264	select RTC_LIB
265	select RTC_MC146818_LIB
266	select SPARSE_IRQ
267	select SRCU
268	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
269	select SYSCTL_EXCEPTION_TRACE
270	select THREAD_INFO_IN_TASK
271	select TRACE_IRQFLAGS_SUPPORT
272	select USER_STACKTRACE_SUPPORT
273	select VIRT_TO_BUS
274	select HAVE_ARCH_KCSAN			if X86_64
275	select X86_FEATURE_NAMES		if PROC_FS
276	select PROC_PID_ARCH_STATUS		if PROC_FS
277	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
278	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
279
280config INSTRUCTION_DECODER
281	def_bool y
282	depends on KPROBES || PERF_EVENTS || UPROBES
283
284config OUTPUT_FORMAT
285	string
286	default "elf32-i386" if X86_32
287	default "elf64-x86-64" if X86_64
288
289config LOCKDEP_SUPPORT
290	def_bool y
291
292config STACKTRACE_SUPPORT
293	def_bool y
294
295config MMU
296	def_bool y
297
298config ARCH_MMAP_RND_BITS_MIN
299	default 28 if 64BIT
300	default 8
301
302config ARCH_MMAP_RND_BITS_MAX
303	default 32 if 64BIT
304	default 16
305
306config ARCH_MMAP_RND_COMPAT_BITS_MIN
307	default 8
308
309config ARCH_MMAP_RND_COMPAT_BITS_MAX
310	default 16
311
312config SBUS
313	bool
314
315config GENERIC_ISA_DMA
316	def_bool y
317	depends on ISA_DMA_API
318
319config GENERIC_BUG
320	def_bool y
321	depends on BUG
322	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
323
324config GENERIC_BUG_RELATIVE_POINTERS
325	bool
326
327config ARCH_MAY_HAVE_PC_FDC
328	def_bool y
329	depends on ISA_DMA_API
330
331config GENERIC_CALIBRATE_DELAY
332	def_bool y
333
334config ARCH_HAS_CPU_RELAX
335	def_bool y
336
337config ARCH_HAS_FILTER_PGPROT
338	def_bool y
339
340config ARCH_HIBERNATION_POSSIBLE
341	def_bool y
342
343config ARCH_NR_GPIO
344	int
345	default 1024 if X86_64
346	default 512
347
348config ARCH_SUSPEND_POSSIBLE
349	def_bool y
350
351config AUDIT_ARCH
352	def_bool y if X86_64
353
354config KASAN_SHADOW_OFFSET
355	hex
356	depends on KASAN
357	default 0xdffffc0000000000
358
359config HAVE_INTEL_TXT
360	def_bool y
361	depends on INTEL_IOMMU && ACPI
362
363config X86_32_SMP
364	def_bool y
365	depends on X86_32 && SMP
366
367config X86_64_SMP
368	def_bool y
369	depends on X86_64 && SMP
370
371config ARCH_SUPPORTS_UPROBES
372	def_bool y
373
374config FIX_EARLYCON_MEM
375	def_bool y
376
377config DYNAMIC_PHYSICAL_MASK
378	bool
379
380config PGTABLE_LEVELS
381	int
382	default 5 if X86_5LEVEL
383	default 4 if X86_64
384	default 3 if X86_PAE
385	default 2
386
387config CC_HAS_SANE_STACKPROTECTOR
388	bool
389	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
390	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
391	help
392	   We have to make sure stack protector is unconditionally disabled if
393	   the compiler produces broken code or if it does not let us control
394	   the segment on 32-bit kernels.
395
396menu "Processor type and features"
397
398config SMP
399	bool "Symmetric multi-processing support"
400	help
401	  This enables support for systems with more than one CPU. If you have
402	  a system with only one CPU, say N. If you have a system with more
403	  than one CPU, say Y.
404
405	  If you say N here, the kernel will run on uni- and multiprocessor
406	  machines, but will use only one CPU of a multiprocessor machine. If
407	  you say Y here, the kernel will run on many, but not all,
408	  uniprocessor machines. On a uniprocessor machine, the kernel
409	  will run faster if you say N here.
410
411	  Note that if you say Y here and choose architecture "586" or
412	  "Pentium" under "Processor family", the kernel will not work on 486
413	  architectures. Similarly, multiprocessor kernels for the "PPro"
414	  architecture may not work on all Pentium based boards.
415
416	  People using multiprocessor machines who say Y here should also say
417	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
418	  Management" code will be disabled if you say Y here.
419
420	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
421	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
422	  <http://www.tldp.org/docs.html#howto>.
423
424	  If you don't know what to do here, say N.
425
426config X86_FEATURE_NAMES
427	bool "Processor feature human-readable names" if EMBEDDED
428	default y
429	help
430	  This option compiles in a table of x86 feature bits and corresponding
431	  names.  This is required to support /proc/cpuinfo and a few kernel
432	  messages.  You can disable this to save space, at the expense of
433	  making those few kernel messages show numeric feature bits instead.
434
435	  If in doubt, say Y.
436
437config X86_X2APIC
438	bool "Support x2apic"
439	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
440	help
441	  This enables x2apic support on CPUs that have this feature.
442
443	  This allows 32-bit apic IDs (so it can support very large systems),
444	  and accesses the local apic via MSRs not via mmio.
445
446	  If you don't know what to do here, say N.
447
448config X86_MPPARSE
449	bool "Enable MPS table" if ACPI
450	default y
451	depends on X86_LOCAL_APIC
452	help
453	  For old smp systems that do not have proper acpi support. Newer systems
454	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
455
456config GOLDFISH
457	def_bool y
458	depends on X86_GOLDFISH
459
460config RETPOLINE
461	bool "Avoid speculative indirect branches in kernel"
462	default y
463	help
464	  Compile kernel with the retpoline compiler options to guard against
465	  kernel-to-user data leaks by avoiding speculative indirect
466	  branches. Requires a compiler with -mindirect-branch=thunk-extern
467	  support for full protection. The kernel may run slower.
468
469config CC_HAS_SLS
470	def_bool $(cc-option,-mharden-sls=all)
471
472config SLS
473	bool "Mitigate Straight-Line-Speculation"
474	depends on CC_HAS_SLS && X86_64
475	default n
476	help
477	  Compile the kernel with straight-line-speculation options to guard
478	  against straight line speculation. The kernel image might be slightly
479	  larger.
480
481config X86_CPU_RESCTRL
482	bool "x86 CPU resource control support"
483	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
484	select KERNFS
485	select PROC_CPU_RESCTRL		if PROC_FS
486	help
487	  Enable x86 CPU resource control support.
488
489	  Provide support for the allocation and monitoring of system resources
490	  usage by the CPU.
491
492	  Intel calls this Intel Resource Director Technology
493	  (Intel(R) RDT). More information about RDT can be found in the
494	  Intel x86 Architecture Software Developer Manual.
495
496	  AMD calls this AMD Platform Quality of Service (AMD QoS).
497	  More information about AMD QoS can be found in the AMD64 Technology
498	  Platform Quality of Service Extensions manual.
499
500	  Say N if unsure.
501
502if X86_32
503config X86_BIGSMP
504	bool "Support for big SMP systems with more than 8 CPUs"
505	depends on SMP
506	help
507	  This option is needed for the systems that have more than 8 CPUs.
508
509config X86_EXTENDED_PLATFORM
510	bool "Support for extended (non-PC) x86 platforms"
511	default y
512	help
513	  If you disable this option then the kernel will only support
514	  standard PC platforms. (which covers the vast majority of
515	  systems out there.)
516
517	  If you enable this option then you'll be able to select support
518	  for the following (non-PC) 32 bit x86 platforms:
519		Goldfish (Android emulator)
520		AMD Elan
521		RDC R-321x SoC
522		SGI 320/540 (Visual Workstation)
523		STA2X11-based (e.g. Northville)
524		Moorestown MID devices
525
526	  If you have one of these systems, or if you want to build a
527	  generic distribution kernel, say Y here - otherwise say N.
528endif
529
530if X86_64
531config X86_EXTENDED_PLATFORM
532	bool "Support for extended (non-PC) x86 platforms"
533	default y
534	help
535	  If you disable this option then the kernel will only support
536	  standard PC platforms. (which covers the vast majority of
537	  systems out there.)
538
539	  If you enable this option then you'll be able to select support
540	  for the following (non-PC) 64 bit x86 platforms:
541		Numascale NumaChip
542		ScaleMP vSMP
543		SGI Ultraviolet
544
545	  If you have one of these systems, or if you want to build a
546	  generic distribution kernel, say Y here - otherwise say N.
547endif
548# This is an alphabetically sorted list of 64 bit extended platforms
549# Please maintain the alphabetic order if and when there are additions
550config X86_NUMACHIP
551	bool "Numascale NumaChip"
552	depends on X86_64
553	depends on X86_EXTENDED_PLATFORM
554	depends on NUMA
555	depends on SMP
556	depends on X86_X2APIC
557	depends on PCI_MMCONFIG
558	help
559	  Adds support for Numascale NumaChip large-SMP systems. Needed to
560	  enable more than ~168 cores.
561	  If you don't have one of these, you should say N here.
562
563config X86_VSMP
564	bool "ScaleMP vSMP"
565	select HYPERVISOR_GUEST
566	select PARAVIRT
567	depends on X86_64 && PCI
568	depends on X86_EXTENDED_PLATFORM
569	depends on SMP
570	help
571	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
572	  supposed to run on these EM64T-based machines.  Only choose this option
573	  if you have one of these machines.
574
575config X86_UV
576	bool "SGI Ultraviolet"
577	depends on X86_64
578	depends on X86_EXTENDED_PLATFORM
579	depends on NUMA
580	depends on EFI
581	depends on KEXEC_CORE
582	depends on X86_X2APIC
583	depends on PCI
584	help
585	  This option is needed in order to support SGI Ultraviolet systems.
586	  If you don't have one of these, you should say N here.
587
588# Following is an alphabetically sorted list of 32 bit extended platforms
589# Please maintain the alphabetic order if and when there are additions
590
591config X86_GOLDFISH
592	bool "Goldfish (Virtual Platform)"
593	depends on X86_EXTENDED_PLATFORM
594	help
595	 Enable support for the Goldfish virtual platform used primarily
596	 for Android development. Unless you are building for the Android
597	 Goldfish emulator say N here.
598
599config X86_INTEL_CE
600	bool "CE4100 TV platform"
601	depends on PCI
602	depends on PCI_GODIRECT
603	depends on X86_IO_APIC
604	depends on X86_32
605	depends on X86_EXTENDED_PLATFORM
606	select X86_REBOOTFIXUPS
607	select OF
608	select OF_EARLY_FLATTREE
609	help
610	  Select for the Intel CE media processor (CE4100) SOC.
611	  This option compiles in support for the CE4100 SOC for settop
612	  boxes and media devices.
613
614config X86_INTEL_MID
615	bool "Intel MID platform support"
616	depends on X86_EXTENDED_PLATFORM
617	depends on X86_PLATFORM_DEVICES
618	depends on PCI
619	depends on X86_64 || (PCI_GOANY && X86_32)
620	depends on X86_IO_APIC
621	select I2C
622	select DW_APB_TIMER
623	select INTEL_SCU_PCI
624	help
625	  Select to build a kernel capable of supporting Intel MID (Mobile
626	  Internet Device) platform systems which do not have the PCI legacy
627	  interfaces. If you are building for a PC class system say N here.
628
629	  Intel MID platforms are based on an Intel processor and chipset which
630	  consume less power than most of the x86 derivatives.
631
632config X86_INTEL_QUARK
633	bool "Intel Quark platform support"
634	depends on X86_32
635	depends on X86_EXTENDED_PLATFORM
636	depends on X86_PLATFORM_DEVICES
637	depends on X86_TSC
638	depends on PCI
639	depends on PCI_GOANY
640	depends on X86_IO_APIC
641	select IOSF_MBI
642	select INTEL_IMR
643	select COMMON_CLK
644	help
645	  Select to include support for Quark X1000 SoC.
646	  Say Y here if you have a Quark based system such as the Arduino
647	  compatible Intel Galileo.
648
649config X86_INTEL_LPSS
650	bool "Intel Low Power Subsystem Support"
651	depends on X86 && ACPI && PCI
652	select COMMON_CLK
653	select PINCTRL
654	select IOSF_MBI
655	help
656	  Select to build support for Intel Low Power Subsystem such as
657	  found on Intel Lynxpoint PCH. Selecting this option enables
658	  things like clock tree (common clock framework) and pincontrol
659	  which are needed by the LPSS peripheral drivers.
660
661config X86_AMD_PLATFORM_DEVICE
662	bool "AMD ACPI2Platform devices support"
663	depends on ACPI
664	select COMMON_CLK
665	select PINCTRL
666	help
667	  Select to interpret AMD specific ACPI device to platform device
668	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
669	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
670	  implemented under PINCTRL subsystem.
671
672config IOSF_MBI
673	tristate "Intel SoC IOSF Sideband support for SoC platforms"
674	depends on PCI
675	help
676	  This option enables sideband register access support for Intel SoC
677	  platforms. On these platforms the IOSF sideband is used in lieu of
678	  MSR's for some register accesses, mostly but not limited to thermal
679	  and power. Drivers may query the availability of this device to
680	  determine if they need the sideband in order to work on these
681	  platforms. The sideband is available on the following SoC products.
682	  This list is not meant to be exclusive.
683	   - BayTrail
684	   - Braswell
685	   - Quark
686
687	  You should say Y if you are running a kernel on one of these SoC's.
688
689config IOSF_MBI_DEBUG
690	bool "Enable IOSF sideband access through debugfs"
691	depends on IOSF_MBI && DEBUG_FS
692	help
693	  Select this option to expose the IOSF sideband access registers (MCR,
694	  MDR, MCRX) through debugfs to write and read register information from
695	  different units on the SoC. This is most useful for obtaining device
696	  state information for debug and analysis. As this is a general access
697	  mechanism, users of this option would have specific knowledge of the
698	  device they want to access.
699
700	  If you don't require the option or are in doubt, say N.
701
702config X86_RDC321X
703	bool "RDC R-321x SoC"
704	depends on X86_32
705	depends on X86_EXTENDED_PLATFORM
706	select M486
707	select X86_REBOOTFIXUPS
708	help
709	  This option is needed for RDC R-321x system-on-chip, also known
710	  as R-8610-(G).
711	  If you don't have one of these chips, you should say N here.
712
713config X86_32_NON_STANDARD
714	bool "Support non-standard 32-bit SMP architectures"
715	depends on X86_32 && SMP
716	depends on X86_EXTENDED_PLATFORM
717	help
718	  This option compiles in the bigsmp and STA2X11 default
719	  subarchitectures.  It is intended for a generic binary
720	  kernel. If you select them all, kernel will probe it one by
721	  one and will fallback to default.
722
723# Alphabetically sorted list of Non standard 32 bit platforms
724
725config X86_SUPPORTS_MEMORY_FAILURE
726	def_bool y
727	# MCE code calls memory_failure():
728	depends on X86_MCE
729	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
730	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
731	depends on X86_64 || !SPARSEMEM
732	select ARCH_SUPPORTS_MEMORY_FAILURE
733
734config STA2X11
735	bool "STA2X11 Companion Chip Support"
736	depends on X86_32_NON_STANDARD && PCI
737	select SWIOTLB
738	select MFD_STA2X11
739	select GPIOLIB
740	help
741	  This adds support for boards based on the STA2X11 IO-Hub,
742	  a.k.a. "ConneXt". The chip is used in place of the standard
743	  PC chipset, so all "standard" peripherals are missing. If this
744	  option is selected the kernel will still be able to boot on
745	  standard PC machines.
746
747config X86_32_IRIS
748	tristate "Eurobraille/Iris poweroff module"
749	depends on X86_32
750	help
751	  The Iris machines from EuroBraille do not have APM or ACPI support
752	  to shut themselves down properly.  A special I/O sequence is
753	  needed to do so, which is what this module does at
754	  kernel shutdown.
755
756	  This is only for Iris machines from EuroBraille.
757
758	  If unused, say N.
759
760config SCHED_OMIT_FRAME_POINTER
761	def_bool y
762	prompt "Single-depth WCHAN output"
763	depends on X86
764	help
765	  Calculate simpler /proc/<PID>/wchan values. If this option
766	  is disabled then wchan values will recurse back to the
767	  caller function. This provides more accurate wchan values,
768	  at the expense of slightly more scheduling overhead.
769
770	  If in doubt, say "Y".
771
772menuconfig HYPERVISOR_GUEST
773	bool "Linux guest support"
774	help
775	  Say Y here to enable options for running Linux under various hyper-
776	  visors. This option enables basic hypervisor detection and platform
777	  setup.
778
779	  If you say N, all options in this submenu will be skipped and
780	  disabled, and Linux guest support won't be built in.
781
782if HYPERVISOR_GUEST
783
784config PARAVIRT
785	bool "Enable paravirtualization code"
786	depends on HAVE_STATIC_CALL
787	help
788	  This changes the kernel so it can modify itself when it is run
789	  under a hypervisor, potentially improving performance significantly
790	  over full virtualization.  However, when run without a hypervisor
791	  the kernel is theoretically slower and slightly larger.
792
793config PARAVIRT_XXL
794	bool
795
796config PARAVIRT_DEBUG
797	bool "paravirt-ops debugging"
798	depends on PARAVIRT && DEBUG_KERNEL
799	help
800	  Enable to debug paravirt_ops internals.  Specifically, BUG if
801	  a paravirt_op is missing when it is called.
802
803config PARAVIRT_SPINLOCKS
804	bool "Paravirtualization layer for spinlocks"
805	depends on PARAVIRT && SMP
806	help
807	  Paravirtualized spinlocks allow a pvops backend to replace the
808	  spinlock implementation with something virtualization-friendly
809	  (for example, block the virtual CPU rather than spinning).
810
811	  It has a minimal impact on native kernels and gives a nice performance
812	  benefit on paravirtualized KVM / Xen kernels.
813
814	  If you are unsure how to answer this question, answer Y.
815
816config X86_HV_CALLBACK_VECTOR
817	def_bool n
818
819source "arch/x86/xen/Kconfig"
820
821config KVM_GUEST
822	bool "KVM Guest support (including kvmclock)"
823	depends on PARAVIRT
824	select PARAVIRT_CLOCK
825	select ARCH_CPUIDLE_HALTPOLL
826	select X86_HV_CALLBACK_VECTOR
827	default y
828	help
829	  This option enables various optimizations for running under the KVM
830	  hypervisor. It includes a paravirtualized clock, so that instead
831	  of relying on a PIT (or probably other) emulation by the
832	  underlying device model, the host provides the guest with
833	  timing infrastructure such as time of day, and system time
834
835config ARCH_CPUIDLE_HALTPOLL
836	def_bool n
837	prompt "Disable host haltpoll when loading haltpoll driver"
838	help
839	  If virtualized under KVM, disable host haltpoll.
840
841config PVH
842	bool "Support for running PVH guests"
843	help
844	  This option enables the PVH entry point for guest virtual machines
845	  as specified in the x86/HVM direct boot ABI.
846
847config PARAVIRT_TIME_ACCOUNTING
848	bool "Paravirtual steal time accounting"
849	depends on PARAVIRT
850	help
851	  Select this option to enable fine granularity task steal time
852	  accounting. Time spent executing other tasks in parallel with
853	  the current vCPU is discounted from the vCPU power. To account for
854	  that, there can be a small performance impact.
855
856	  If in doubt, say N here.
857
858config PARAVIRT_CLOCK
859	bool
860
861config JAILHOUSE_GUEST
862	bool "Jailhouse non-root cell support"
863	depends on X86_64 && PCI
864	select X86_PM_TIMER
865	help
866	  This option allows to run Linux as guest in a Jailhouse non-root
867	  cell. You can leave this option disabled if you only want to start
868	  Jailhouse and run Linux afterwards in the root cell.
869
870config ACRN_GUEST
871	bool "ACRN Guest support"
872	depends on X86_64
873	select X86_HV_CALLBACK_VECTOR
874	help
875	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
876	  a flexible, lightweight reference open-source hypervisor, built with
877	  real-time and safety-criticality in mind. It is built for embedded
878	  IOT with small footprint and real-time features. More details can be
879	  found in https://projectacrn.org/.
880
881endif #HYPERVISOR_GUEST
882
883source "arch/x86/Kconfig.cpu"
884
885config HPET_TIMER
886	def_bool X86_64
887	prompt "HPET Timer Support" if X86_32
888	help
889	  Use the IA-PC HPET (High Precision Event Timer) to manage
890	  time in preference to the PIT and RTC, if a HPET is
891	  present.
892	  HPET is the next generation timer replacing legacy 8254s.
893	  The HPET provides a stable time base on SMP
894	  systems, unlike the TSC, but it is more expensive to access,
895	  as it is off-chip.  The interface used is documented
896	  in the HPET spec, revision 1.
897
898	  You can safely choose Y here.  However, HPET will only be
899	  activated if the platform and the BIOS support this feature.
900	  Otherwise the 8254 will be used for timing services.
901
902	  Choose N to continue using the legacy 8254 timer.
903
904config HPET_EMULATE_RTC
905	def_bool y
906	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
907
908# Mark as expert because too many people got it wrong.
909# The code disables itself when not needed.
910config DMI
911	default y
912	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
913	bool "Enable DMI scanning" if EXPERT
914	help
915	  Enabled scanning of DMI to identify machine quirks. Say Y
916	  here unless you have verified that your setup is not
917	  affected by entries in the DMI blacklist. Required by PNP
918	  BIOS code.
919
920config GART_IOMMU
921	bool "Old AMD GART IOMMU support"
922	select DMA_OPS
923	select IOMMU_HELPER
924	select SWIOTLB
925	depends on X86_64 && PCI && AMD_NB
926	help
927	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
928	  GART based hardware IOMMUs.
929
930	  The GART supports full DMA access for devices with 32-bit access
931	  limitations, on systems with more than 3 GB. This is usually needed
932	  for USB, sound, many IDE/SATA chipsets and some other devices.
933
934	  Newer systems typically have a modern AMD IOMMU, supported via
935	  the CONFIG_AMD_IOMMU=y config option.
936
937	  In normal configurations this driver is only active when needed:
938	  there's more than 3 GB of memory and the system contains a
939	  32-bit limited device.
940
941	  If unsure, say Y.
942
943config MAXSMP
944	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
945	depends on X86_64 && SMP && DEBUG_KERNEL
946	select CPUMASK_OFFSTACK
947	help
948	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
949	  If unsure, say N.
950
951#
952# The maximum number of CPUs supported:
953#
954# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
955# and which can be configured interactively in the
956# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
957#
958# The ranges are different on 32-bit and 64-bit kernels, depending on
959# hardware capabilities and scalability features of the kernel.
960#
961# ( If MAXSMP is enabled we just use the highest possible value and disable
962#   interactive configuration. )
963#
964
965config NR_CPUS_RANGE_BEGIN
966	int
967	default NR_CPUS_RANGE_END if MAXSMP
968	default    1 if !SMP
969	default    2
970
971config NR_CPUS_RANGE_END
972	int
973	depends on X86_32
974	default   64 if  SMP &&  X86_BIGSMP
975	default    8 if  SMP && !X86_BIGSMP
976	default    1 if !SMP
977
978config NR_CPUS_RANGE_END
979	int
980	depends on X86_64
981	default 8192 if  SMP && CPUMASK_OFFSTACK
982	default  512 if  SMP && !CPUMASK_OFFSTACK
983	default    1 if !SMP
984
985config NR_CPUS_DEFAULT
986	int
987	depends on X86_32
988	default   32 if  X86_BIGSMP
989	default    8 if  SMP
990	default    1 if !SMP
991
992config NR_CPUS_DEFAULT
993	int
994	depends on X86_64
995	default 8192 if  MAXSMP
996	default   64 if  SMP
997	default    1 if !SMP
998
999config NR_CPUS
1000	int "Maximum number of CPUs" if SMP && !MAXSMP
1001	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1002	default NR_CPUS_DEFAULT
1003	help
1004	  This allows you to specify the maximum number of CPUs which this
1005	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1006	  supported value is 8192, otherwise the maximum value is 512.  The
1007	  minimum value which makes sense is 2.
1008
1009	  This is purely to save memory: each supported CPU adds about 8KB
1010	  to the kernel image.
1011
1012config SCHED_CLUSTER
1013	bool "Cluster scheduler support"
1014	depends on SMP
1015	default y
1016	help
1017	  Cluster scheduler support improves the CPU scheduler's decision
1018	  making when dealing with machines that have clusters of CPUs.
1019	  Cluster usually means a couple of CPUs which are placed closely
1020	  by sharing mid-level caches, last-level cache tags or internal
1021	  busses.
1022
1023config SCHED_SMT
1024	def_bool y if SMP
1025
1026config SCHED_MC
1027	def_bool y
1028	prompt "Multi-core scheduler support"
1029	depends on SMP
1030	help
1031	  Multi-core scheduler support improves the CPU scheduler's decision
1032	  making when dealing with multi-core CPU chips at a cost of slightly
1033	  increased overhead in some places. If unsure say N here.
1034
1035config SCHED_MC_PRIO
1036	bool "CPU core priorities scheduler support"
1037	depends on SCHED_MC && CPU_SUP_INTEL
1038	select X86_INTEL_PSTATE
1039	select CPU_FREQ
1040	default y
1041	help
1042	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1043	  core ordering determined at manufacturing time, which allows
1044	  certain cores to reach higher turbo frequencies (when running
1045	  single threaded workloads) than others.
1046
1047	  Enabling this kernel feature teaches the scheduler about
1048	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1049	  scheduler's CPU selection logic accordingly, so that higher
1050	  overall system performance can be achieved.
1051
1052	  This feature will have no effect on CPUs without this feature.
1053
1054	  If unsure say Y here.
1055
1056config UP_LATE_INIT
1057	def_bool y
1058	depends on !SMP && X86_LOCAL_APIC
1059
1060config X86_UP_APIC
1061	bool "Local APIC support on uniprocessors" if !PCI_MSI
1062	default PCI_MSI
1063	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1064	help
1065	  A local APIC (Advanced Programmable Interrupt Controller) is an
1066	  integrated interrupt controller in the CPU. If you have a single-CPU
1067	  system which has a processor with a local APIC, you can say Y here to
1068	  enable and use it. If you say Y here even though your machine doesn't
1069	  have a local APIC, then the kernel will still run with no slowdown at
1070	  all. The local APIC supports CPU-generated self-interrupts (timer,
1071	  performance counters), and the NMI watchdog which detects hard
1072	  lockups.
1073
1074config X86_UP_IOAPIC
1075	bool "IO-APIC support on uniprocessors"
1076	depends on X86_UP_APIC
1077	help
1078	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1079	  SMP-capable replacement for PC-style interrupt controllers. Most
1080	  SMP systems and many recent uniprocessor systems have one.
1081
1082	  If you have a single-CPU system with an IO-APIC, you can say Y here
1083	  to use it. If you say Y here even though your machine doesn't have
1084	  an IO-APIC, then the kernel will still run with no slowdown at all.
1085
1086config X86_LOCAL_APIC
1087	def_bool y
1088	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1089	select IRQ_DOMAIN_HIERARCHY
1090	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1091
1092config X86_IO_APIC
1093	def_bool y
1094	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1095
1096config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1097	bool "Reroute for broken boot IRQs"
1098	depends on X86_IO_APIC
1099	help
1100	  This option enables a workaround that fixes a source of
1101	  spurious interrupts. This is recommended when threaded
1102	  interrupt handling is used on systems where the generation of
1103	  superfluous "boot interrupts" cannot be disabled.
1104
1105	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1106	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1107	  kernel does during interrupt handling). On chipsets where this
1108	  boot IRQ generation cannot be disabled, this workaround keeps
1109	  the original IRQ line masked so that only the equivalent "boot
1110	  IRQ" is delivered to the CPUs. The workaround also tells the
1111	  kernel to set up the IRQ handler on the boot IRQ line. In this
1112	  way only one interrupt is delivered to the kernel. Otherwise
1113	  the spurious second interrupt may cause the kernel to bring
1114	  down (vital) interrupt lines.
1115
1116	  Only affects "broken" chipsets. Interrupt sharing may be
1117	  increased on these systems.
1118
1119config X86_MCE
1120	bool "Machine Check / overheating reporting"
1121	select GENERIC_ALLOCATOR
1122	default y
1123	help
1124	  Machine Check support allows the processor to notify the
1125	  kernel if it detects a problem (e.g. overheating, data corruption).
1126	  The action the kernel takes depends on the severity of the problem,
1127	  ranging from warning messages to halting the machine.
1128
1129config X86_MCELOG_LEGACY
1130	bool "Support for deprecated /dev/mcelog character device"
1131	depends on X86_MCE
1132	help
1133	  Enable support for /dev/mcelog which is needed by the old mcelog
1134	  userspace logging daemon. Consider switching to the new generation
1135	  rasdaemon solution.
1136
1137config X86_MCE_INTEL
1138	def_bool y
1139	prompt "Intel MCE features"
1140	depends on X86_MCE && X86_LOCAL_APIC
1141	help
1142	   Additional support for intel specific MCE features such as
1143	   the thermal monitor.
1144
1145config X86_MCE_AMD
1146	def_bool y
1147	prompt "AMD MCE features"
1148	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1149	help
1150	   Additional support for AMD specific MCE features such as
1151	   the DRAM Error Threshold.
1152
1153config X86_ANCIENT_MCE
1154	bool "Support for old Pentium 5 / WinChip machine checks"
1155	depends on X86_32 && X86_MCE
1156	help
1157	  Include support for machine check handling on old Pentium 5 or WinChip
1158	  systems. These typically need to be enabled explicitly on the command
1159	  line.
1160
1161config X86_MCE_THRESHOLD
1162	depends on X86_MCE_AMD || X86_MCE_INTEL
1163	def_bool y
1164
1165config X86_MCE_INJECT
1166	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1167	tristate "Machine check injector support"
1168	help
1169	  Provide support for injecting machine checks for testing purposes.
1170	  If you don't know what a machine check is and you don't do kernel
1171	  QA it is safe to say n.
1172
1173source "arch/x86/events/Kconfig"
1174
1175config X86_LEGACY_VM86
1176	bool "Legacy VM86 support"
1177	depends on X86_32
1178	help
1179	  This option allows user programs to put the CPU into V8086
1180	  mode, which is an 80286-era approximation of 16-bit real mode.
1181
1182	  Some very old versions of X and/or vbetool require this option
1183	  for user mode setting.  Similarly, DOSEMU will use it if
1184	  available to accelerate real mode DOS programs.  However, any
1185	  recent version of DOSEMU, X, or vbetool should be fully
1186	  functional even without kernel VM86 support, as they will all
1187	  fall back to software emulation. Nevertheless, if you are using
1188	  a 16-bit DOS program where 16-bit performance matters, vm86
1189	  mode might be faster than emulation and you might want to
1190	  enable this option.
1191
1192	  Note that any app that works on a 64-bit kernel is unlikely to
1193	  need this option, as 64-bit kernels don't, and can't, support
1194	  V8086 mode. This option is also unrelated to 16-bit protected
1195	  mode and is not needed to run most 16-bit programs under Wine.
1196
1197	  Enabling this option increases the complexity of the kernel
1198	  and slows down exception handling a tiny bit.
1199
1200	  If unsure, say N here.
1201
1202config VM86
1203	bool
1204	default X86_LEGACY_VM86
1205
1206config X86_16BIT
1207	bool "Enable support for 16-bit segments" if EXPERT
1208	default y
1209	depends on MODIFY_LDT_SYSCALL
1210	help
1211	  This option is required by programs like Wine to run 16-bit
1212	  protected mode legacy code on x86 processors.  Disabling
1213	  this option saves about 300 bytes on i386, or around 6K text
1214	  plus 16K runtime memory on x86-64,
1215
1216config X86_ESPFIX32
1217	def_bool y
1218	depends on X86_16BIT && X86_32
1219
1220config X86_ESPFIX64
1221	def_bool y
1222	depends on X86_16BIT && X86_64
1223
1224config X86_VSYSCALL_EMULATION
1225	bool "Enable vsyscall emulation" if EXPERT
1226	default y
1227	depends on X86_64
1228	help
1229	 This enables emulation of the legacy vsyscall page.  Disabling
1230	 it is roughly equivalent to booting with vsyscall=none, except
1231	 that it will also disable the helpful warning if a program
1232	 tries to use a vsyscall.  With this option set to N, offending
1233	 programs will just segfault, citing addresses of the form
1234	 0xffffffffff600?00.
1235
1236	 This option is required by many programs built before 2013, and
1237	 care should be used even with newer programs if set to N.
1238
1239	 Disabling this option saves about 7K of kernel size and
1240	 possibly 4K of additional runtime pagetable memory.
1241
1242config X86_IOPL_IOPERM
1243	bool "IOPERM and IOPL Emulation"
1244	default y
1245	help
1246	  This enables the ioperm() and iopl() syscalls which are necessary
1247	  for legacy applications.
1248
1249	  Legacy IOPL support is an overbroad mechanism which allows user
1250	  space aside of accessing all 65536 I/O ports also to disable
1251	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1252	  capabilities and permission from potentially active security
1253	  modules.
1254
1255	  The emulation restricts the functionality of the syscall to
1256	  only allowing the full range I/O port access, but prevents the
1257	  ability to disable interrupts from user space which would be
1258	  granted if the hardware IOPL mechanism would be used.
1259
1260config TOSHIBA
1261	tristate "Toshiba Laptop support"
1262	depends on X86_32
1263	help
1264	  This adds a driver to safely access the System Management Mode of
1265	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1266	  not work on models with a Phoenix BIOS. The System Management Mode
1267	  is used to set the BIOS and power saving options on Toshiba portables.
1268
1269	  For information on utilities to make use of this driver see the
1270	  Toshiba Linux utilities web site at:
1271	  <http://www.buzzard.org.uk/toshiba/>.
1272
1273	  Say Y if you intend to run this kernel on a Toshiba portable.
1274	  Say N otherwise.
1275
1276config I8K
1277	tristate "Dell i8k legacy laptop support"
1278	depends on HWMON
1279	depends on PROC_FS
1280	select SENSORS_DELL_SMM
1281	help
1282	  This option enables legacy /proc/i8k userspace interface in hwmon
1283	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1284	  temperature and allows controlling fan speeds of Dell laptops via
1285	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1286	  it reports also power and hotkey status. For fan speed control is
1287	  needed userspace package i8kutils.
1288
1289	  Say Y if you intend to run this kernel on old Dell laptops or want to
1290	  use userspace package i8kutils.
1291	  Say N otherwise.
1292
1293config X86_REBOOTFIXUPS
1294	bool "Enable X86 board specific fixups for reboot"
1295	depends on X86_32
1296	help
1297	  This enables chipset and/or board specific fixups to be done
1298	  in order to get reboot to work correctly. This is only needed on
1299	  some combinations of hardware and BIOS. The symptom, for which
1300	  this config is intended, is when reboot ends with a stalled/hung
1301	  system.
1302
1303	  Currently, the only fixup is for the Geode machines using
1304	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1305
1306	  Say Y if you want to enable the fixup. Currently, it's safe to
1307	  enable this option even if you don't need it.
1308	  Say N otherwise.
1309
1310config MICROCODE
1311	bool "CPU microcode loading support"
1312	default y
1313	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1314	help
1315	  If you say Y here, you will be able to update the microcode on
1316	  Intel and AMD processors. The Intel support is for the IA32 family,
1317	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1318	  AMD support is for families 0x10 and later. You will obviously need
1319	  the actual microcode binary data itself which is not shipped with
1320	  the Linux kernel.
1321
1322	  The preferred method to load microcode from a detached initrd is described
1323	  in Documentation/x86/microcode.rst. For that you need to enable
1324	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1325	  initrd for microcode blobs.
1326
1327	  In addition, you can build the microcode into the kernel. For that you
1328	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1329	  config option.
1330
1331config MICROCODE_INTEL
1332	bool "Intel microcode loading support"
1333	depends on MICROCODE
1334	default MICROCODE
1335	help
1336	  This options enables microcode patch loading support for Intel
1337	  processors.
1338
1339	  For the current Intel microcode data package go to
1340	  <https://downloadcenter.intel.com> and search for
1341	  'Linux Processor Microcode Data File'.
1342
1343config MICROCODE_AMD
1344	bool "AMD microcode loading support"
1345	depends on MICROCODE
1346	help
1347	  If you select this option, microcode patch loading support for AMD
1348	  processors will be enabled.
1349
1350config MICROCODE_OLD_INTERFACE
1351	bool "Ancient loading interface (DEPRECATED)"
1352	default n
1353	depends on MICROCODE
1354	help
1355	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1356	  which was used by userspace tools like iucode_tool and microcode.ctl.
1357	  It is inadequate because it runs too late to be able to properly
1358	  load microcode on a machine and it needs special tools. Instead, you
1359	  should've switched to the early loading method with the initrd or
1360	  builtin microcode by now: Documentation/x86/microcode.rst
1361
1362config X86_MSR
1363	tristate "/dev/cpu/*/msr - Model-specific register support"
1364	help
1365	  This device gives privileged processes access to the x86
1366	  Model-Specific Registers (MSRs).  It is a character device with
1367	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1368	  MSR accesses are directed to a specific CPU on multi-processor
1369	  systems.
1370
1371config X86_CPUID
1372	tristate "/dev/cpu/*/cpuid - CPU information support"
1373	help
1374	  This device gives processes access to the x86 CPUID instruction to
1375	  be executed on a specific processor.  It is a character device
1376	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1377	  /dev/cpu/31/cpuid.
1378
1379choice
1380	prompt "High Memory Support"
1381	default HIGHMEM4G
1382	depends on X86_32
1383
1384config NOHIGHMEM
1385	bool "off"
1386	help
1387	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1388	  However, the address space of 32-bit x86 processors is only 4
1389	  Gigabytes large. That means that, if you have a large amount of
1390	  physical memory, not all of it can be "permanently mapped" by the
1391	  kernel. The physical memory that's not permanently mapped is called
1392	  "high memory".
1393
1394	  If you are compiling a kernel which will never run on a machine with
1395	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1396	  choice and suitable for most users). This will result in a "3GB/1GB"
1397	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1398	  space and the remaining part of the 4GB virtual memory space is used
1399	  by the kernel to permanently map as much physical memory as
1400	  possible.
1401
1402	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1403	  answer "4GB" here.
1404
1405	  If more than 4 Gigabytes is used then answer "64GB" here. This
1406	  selection turns Intel PAE (Physical Address Extension) mode on.
1407	  PAE implements 3-level paging on IA32 processors. PAE is fully
1408	  supported by Linux, PAE mode is implemented on all recent Intel
1409	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1410	  then the kernel will not boot on CPUs that don't support PAE!
1411
1412	  The actual amount of total physical memory will either be
1413	  auto detected or can be forced by using a kernel command line option
1414	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1415	  your boot loader (lilo or loadlin) about how to pass options to the
1416	  kernel at boot time.)
1417
1418	  If unsure, say "off".
1419
1420config HIGHMEM4G
1421	bool "4GB"
1422	help
1423	  Select this if you have a 32-bit processor and between 1 and 4
1424	  gigabytes of physical RAM.
1425
1426config HIGHMEM64G
1427	bool "64GB"
1428	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1429	select X86_PAE
1430	help
1431	  Select this if you have a 32-bit processor and more than 4
1432	  gigabytes of physical RAM.
1433
1434endchoice
1435
1436choice
1437	prompt "Memory split" if EXPERT
1438	default VMSPLIT_3G
1439	depends on X86_32
1440	help
1441	  Select the desired split between kernel and user memory.
1442
1443	  If the address range available to the kernel is less than the
1444	  physical memory installed, the remaining memory will be available
1445	  as "high memory". Accessing high memory is a little more costly
1446	  than low memory, as it needs to be mapped into the kernel first.
1447	  Note that increasing the kernel address space limits the range
1448	  available to user programs, making the address space there
1449	  tighter.  Selecting anything other than the default 3G/1G split
1450	  will also likely make your kernel incompatible with binary-only
1451	  kernel modules.
1452
1453	  If you are not absolutely sure what you are doing, leave this
1454	  option alone!
1455
1456	config VMSPLIT_3G
1457		bool "3G/1G user/kernel split"
1458	config VMSPLIT_3G_OPT
1459		depends on !X86_PAE
1460		bool "3G/1G user/kernel split (for full 1G low memory)"
1461	config VMSPLIT_2G
1462		bool "2G/2G user/kernel split"
1463	config VMSPLIT_2G_OPT
1464		depends on !X86_PAE
1465		bool "2G/2G user/kernel split (for full 2G low memory)"
1466	config VMSPLIT_1G
1467		bool "1G/3G user/kernel split"
1468endchoice
1469
1470config PAGE_OFFSET
1471	hex
1472	default 0xB0000000 if VMSPLIT_3G_OPT
1473	default 0x80000000 if VMSPLIT_2G
1474	default 0x78000000 if VMSPLIT_2G_OPT
1475	default 0x40000000 if VMSPLIT_1G
1476	default 0xC0000000
1477	depends on X86_32
1478
1479config HIGHMEM
1480	def_bool y
1481	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1482
1483config X86_PAE
1484	bool "PAE (Physical Address Extension) Support"
1485	depends on X86_32 && !HIGHMEM4G
1486	select PHYS_ADDR_T_64BIT
1487	select SWIOTLB
1488	help
1489	  PAE is required for NX support, and furthermore enables
1490	  larger swapspace support for non-overcommit purposes. It
1491	  has the cost of more pagetable lookup overhead, and also
1492	  consumes more pagetable space per process.
1493
1494config X86_5LEVEL
1495	bool "Enable 5-level page tables support"
1496	default y
1497	select DYNAMIC_MEMORY_LAYOUT
1498	select SPARSEMEM_VMEMMAP
1499	depends on X86_64
1500	help
1501	  5-level paging enables access to larger address space:
1502	  upto 128 PiB of virtual address space and 4 PiB of
1503	  physical address space.
1504
1505	  It will be supported by future Intel CPUs.
1506
1507	  A kernel with the option enabled can be booted on machines that
1508	  support 4- or 5-level paging.
1509
1510	  See Documentation/x86/x86_64/5level-paging.rst for more
1511	  information.
1512
1513	  Say N if unsure.
1514
1515config X86_DIRECT_GBPAGES
1516	def_bool y
1517	depends on X86_64
1518	help
1519	  Certain kernel features effectively disable kernel
1520	  linear 1 GB mappings (even if the CPU otherwise
1521	  supports them), so don't confuse the user by printing
1522	  that we have them enabled.
1523
1524config X86_CPA_STATISTICS
1525	bool "Enable statistic for Change Page Attribute"
1526	depends on DEBUG_FS
1527	help
1528	  Expose statistics about the Change Page Attribute mechanism, which
1529	  helps to determine the effectiveness of preserving large and huge
1530	  page mappings when mapping protections are changed.
1531
1532config X86_MEM_ENCRYPT
1533	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1534	select DYNAMIC_PHYSICAL_MASK
1535	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
1536	def_bool n
1537
1538config AMD_MEM_ENCRYPT
1539	bool "AMD Secure Memory Encryption (SME) support"
1540	depends on X86_64 && CPU_SUP_AMD
1541	select DMA_COHERENT_POOL
1542	select ARCH_USE_MEMREMAP_PROT
1543	select INSTRUCTION_DECODER
1544	select ARCH_HAS_CC_PLATFORM
1545	select X86_MEM_ENCRYPT
1546	help
1547	  Say yes to enable support for the encryption of system memory.
1548	  This requires an AMD processor that supports Secure Memory
1549	  Encryption (SME).
1550
1551config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1552	bool "Activate AMD Secure Memory Encryption (SME) by default"
1553	depends on AMD_MEM_ENCRYPT
1554	help
1555	  Say yes to have system memory encrypted by default if running on
1556	  an AMD processor that supports Secure Memory Encryption (SME).
1557
1558	  If set to Y, then the encryption of system memory can be
1559	  deactivated with the mem_encrypt=off command line option.
1560
1561	  If set to N, then the encryption of system memory can be
1562	  activated with the mem_encrypt=on command line option.
1563
1564# Common NUMA Features
1565config NUMA
1566	bool "NUMA Memory Allocation and Scheduler Support"
1567	depends on SMP
1568	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1569	default y if X86_BIGSMP
1570	select USE_PERCPU_NUMA_NODE_ID
1571	help
1572	  Enable NUMA (Non-Uniform Memory Access) support.
1573
1574	  The kernel will try to allocate memory used by a CPU on the
1575	  local memory controller of the CPU and add some more
1576	  NUMA awareness to the kernel.
1577
1578	  For 64-bit this is recommended if the system is Intel Core i7
1579	  (or later), AMD Opteron, or EM64T NUMA.
1580
1581	  For 32-bit this is only needed if you boot a 32-bit
1582	  kernel on a 64-bit NUMA platform.
1583
1584	  Otherwise, you should say N.
1585
1586config AMD_NUMA
1587	def_bool y
1588	prompt "Old style AMD Opteron NUMA detection"
1589	depends on X86_64 && NUMA && PCI
1590	help
1591	  Enable AMD NUMA node topology detection.  You should say Y here if
1592	  you have a multi processor AMD system. This uses an old method to
1593	  read the NUMA configuration directly from the builtin Northbridge
1594	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1595	  which also takes priority if both are compiled in.
1596
1597config X86_64_ACPI_NUMA
1598	def_bool y
1599	prompt "ACPI NUMA detection"
1600	depends on X86_64 && NUMA && ACPI && PCI
1601	select ACPI_NUMA
1602	help
1603	  Enable ACPI SRAT based node topology detection.
1604
1605config NUMA_EMU
1606	bool "NUMA emulation"
1607	depends on NUMA
1608	help
1609	  Enable NUMA emulation. A flat machine will be split
1610	  into virtual nodes when booted with "numa=fake=N", where N is the
1611	  number of nodes. This is only useful for debugging.
1612
1613config NODES_SHIFT
1614	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1615	range 1 10
1616	default "10" if MAXSMP
1617	default "6" if X86_64
1618	default "3"
1619	depends on NUMA
1620	help
1621	  Specify the maximum number of NUMA Nodes available on the target
1622	  system.  Increases memory reserved to accommodate various tables.
1623
1624config ARCH_FLATMEM_ENABLE
1625	def_bool y
1626	depends on X86_32 && !NUMA
1627
1628config ARCH_SPARSEMEM_ENABLE
1629	def_bool y
1630	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1631	select SPARSEMEM_STATIC if X86_32
1632	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1633
1634config ARCH_SPARSEMEM_DEFAULT
1635	def_bool X86_64 || (NUMA && X86_32)
1636
1637config ARCH_SELECT_MEMORY_MODEL
1638	def_bool y
1639	depends on ARCH_SPARSEMEM_ENABLE
1640
1641config ARCH_MEMORY_PROBE
1642	bool "Enable sysfs memory/probe interface"
1643	depends on MEMORY_HOTPLUG
1644	help
1645	  This option enables a sysfs memory/probe interface for testing.
1646	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1647	  If you are unsure how to answer this question, answer N.
1648
1649config ARCH_PROC_KCORE_TEXT
1650	def_bool y
1651	depends on X86_64 && PROC_KCORE
1652
1653config ILLEGAL_POINTER_VALUE
1654	hex
1655	default 0 if X86_32
1656	default 0xdead000000000000 if X86_64
1657
1658config X86_PMEM_LEGACY_DEVICE
1659	bool
1660
1661config X86_PMEM_LEGACY
1662	tristate "Support non-standard NVDIMMs and ADR protected memory"
1663	depends on PHYS_ADDR_T_64BIT
1664	depends on BLK_DEV
1665	select X86_PMEM_LEGACY_DEVICE
1666	select NUMA_KEEP_MEMINFO if NUMA
1667	select LIBNVDIMM
1668	help
1669	  Treat memory marked using the non-standard e820 type of 12 as used
1670	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1671	  The kernel will offer these regions to the 'pmem' driver so
1672	  they can be used for persistent storage.
1673
1674	  Say Y if unsure.
1675
1676config HIGHPTE
1677	bool "Allocate 3rd-level pagetables from highmem"
1678	depends on HIGHMEM
1679	help
1680	  The VM uses one page table entry for each page of physical memory.
1681	  For systems with a lot of RAM, this can be wasteful of precious
1682	  low memory.  Setting this option will put user-space page table
1683	  entries in high memory.
1684
1685config X86_CHECK_BIOS_CORRUPTION
1686	bool "Check for low memory corruption"
1687	help
1688	  Periodically check for memory corruption in low memory, which
1689	  is suspected to be caused by BIOS.  Even when enabled in the
1690	  configuration, it is disabled at runtime.  Enable it by
1691	  setting "memory_corruption_check=1" on the kernel command
1692	  line.  By default it scans the low 64k of memory every 60
1693	  seconds; see the memory_corruption_check_size and
1694	  memory_corruption_check_period parameters in
1695	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1696
1697	  When enabled with the default parameters, this option has
1698	  almost no overhead, as it reserves a relatively small amount
1699	  of memory and scans it infrequently.  It both detects corruption
1700	  and prevents it from affecting the running system.
1701
1702	  It is, however, intended as a diagnostic tool; if repeatable
1703	  BIOS-originated corruption always affects the same memory,
1704	  you can use memmap= to prevent the kernel from using that
1705	  memory.
1706
1707config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1708	bool "Set the default setting of memory_corruption_check"
1709	depends on X86_CHECK_BIOS_CORRUPTION
1710	default y
1711	help
1712	  Set whether the default state of memory_corruption_check is
1713	  on or off.
1714
1715config MATH_EMULATION
1716	bool
1717	depends on MODIFY_LDT_SYSCALL
1718	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1719	help
1720	  Linux can emulate a math coprocessor (used for floating point
1721	  operations) if you don't have one. 486DX and Pentium processors have
1722	  a math coprocessor built in, 486SX and 386 do not, unless you added
1723	  a 487DX or 387, respectively. (The messages during boot time can
1724	  give you some hints here ["man dmesg"].) Everyone needs either a
1725	  coprocessor or this emulation.
1726
1727	  If you don't have a math coprocessor, you need to say Y here; if you
1728	  say Y here even though you have a coprocessor, the coprocessor will
1729	  be used nevertheless. (This behavior can be changed with the kernel
1730	  command line option "no387", which comes handy if your coprocessor
1731	  is broken. Try "man bootparam" or see the documentation of your boot
1732	  loader (lilo or loadlin) about how to pass options to the kernel at
1733	  boot time.) This means that it is a good idea to say Y here if you
1734	  intend to use this kernel on different machines.
1735
1736	  More information about the internals of the Linux math coprocessor
1737	  emulation can be found in <file:arch/x86/math-emu/README>.
1738
1739	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1740	  kernel, it won't hurt.
1741
1742config MTRR
1743	def_bool y
1744	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1745	help
1746	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1747	  the Memory Type Range Registers (MTRRs) may be used to control
1748	  processor access to memory ranges. This is most useful if you have
1749	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1750	  allows bus write transfers to be combined into a larger transfer
1751	  before bursting over the PCI/AGP bus. This can increase performance
1752	  of image write operations 2.5 times or more. Saying Y here creates a
1753	  /proc/mtrr file which may be used to manipulate your processor's
1754	  MTRRs. Typically the X server should use this.
1755
1756	  This code has a reasonably generic interface so that similar
1757	  control registers on other processors can be easily supported
1758	  as well:
1759
1760	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1761	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1762	  these, the ARRs are used to emulate the MTRRs.
1763	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1764	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1765	  write-combining. All of these processors are supported by this code
1766	  and it makes sense to say Y here if you have one of them.
1767
1768	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1769	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1770	  can lead to all sorts of problems, so it's good to say Y here.
1771
1772	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1773	  just add about 9 KB to your kernel.
1774
1775	  See <file:Documentation/x86/mtrr.rst> for more information.
1776
1777config MTRR_SANITIZER
1778	def_bool y
1779	prompt "MTRR cleanup support"
1780	depends on MTRR
1781	help
1782	  Convert MTRR layout from continuous to discrete, so X drivers can
1783	  add writeback entries.
1784
1785	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1786	  The largest mtrr entry size for a continuous block can be set with
1787	  mtrr_chunk_size.
1788
1789	  If unsure, say Y.
1790
1791config MTRR_SANITIZER_ENABLE_DEFAULT
1792	int "MTRR cleanup enable value (0-1)"
1793	range 0 1
1794	default "0"
1795	depends on MTRR_SANITIZER
1796	help
1797	  Enable mtrr cleanup default value
1798
1799config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1800	int "MTRR cleanup spare reg num (0-7)"
1801	range 0 7
1802	default "1"
1803	depends on MTRR_SANITIZER
1804	help
1805	  mtrr cleanup spare entries default, it can be changed via
1806	  mtrr_spare_reg_nr=N on the kernel command line.
1807
1808config X86_PAT
1809	def_bool y
1810	prompt "x86 PAT support" if EXPERT
1811	depends on MTRR
1812	help
1813	  Use PAT attributes to setup page level cache control.
1814
1815	  PATs are the modern equivalents of MTRRs and are much more
1816	  flexible than MTRRs.
1817
1818	  Say N here if you see bootup problems (boot crash, boot hang,
1819	  spontaneous reboots) or a non-working video driver.
1820
1821	  If unsure, say Y.
1822
1823config ARCH_USES_PG_UNCACHED
1824	def_bool y
1825	depends on X86_PAT
1826
1827config ARCH_RANDOM
1828	def_bool y
1829	prompt "x86 architectural random number generator" if EXPERT
1830	help
1831	  Enable the x86 architectural RDRAND instruction
1832	  (Intel Bull Mountain technology) to generate random numbers.
1833	  If supported, this is a high bandwidth, cryptographically
1834	  secure hardware random number generator.
1835
1836config X86_SMAP
1837	def_bool y
1838	prompt "Supervisor Mode Access Prevention" if EXPERT
1839	help
1840	  Supervisor Mode Access Prevention (SMAP) is a security
1841	  feature in newer Intel processors.  There is a small
1842	  performance cost if this enabled and turned on; there is
1843	  also a small increase in the kernel size if this is enabled.
1844
1845	  If unsure, say Y.
1846
1847config X86_UMIP
1848	def_bool y
1849	prompt "User Mode Instruction Prevention" if EXPERT
1850	help
1851	  User Mode Instruction Prevention (UMIP) is a security feature in
1852	  some x86 processors. If enabled, a general protection fault is
1853	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1854	  executed in user mode. These instructions unnecessarily expose
1855	  information about the hardware state.
1856
1857	  The vast majority of applications do not use these instructions.
1858	  For the very few that do, software emulation is provided in
1859	  specific cases in protected and virtual-8086 modes. Emulated
1860	  results are dummy.
1861
1862config X86_INTEL_MEMORY_PROTECTION_KEYS
1863	prompt "Memory Protection Keys"
1864	def_bool y
1865	# Note: only available in 64-bit mode
1866	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1867	select ARCH_USES_HIGH_VMA_FLAGS
1868	select ARCH_HAS_PKEYS
1869	help
1870	  Memory Protection Keys provides a mechanism for enforcing
1871	  page-based protections, but without requiring modification of the
1872	  page tables when an application changes protection domains.
1873
1874	  For details, see Documentation/core-api/protection-keys.rst
1875
1876	  If unsure, say y.
1877
1878choice
1879	prompt "TSX enable mode"
1880	depends on CPU_SUP_INTEL
1881	default X86_INTEL_TSX_MODE_OFF
1882	help
1883	  Intel's TSX (Transactional Synchronization Extensions) feature
1884	  allows to optimize locking protocols through lock elision which
1885	  can lead to a noticeable performance boost.
1886
1887	  On the other hand it has been shown that TSX can be exploited
1888	  to form side channel attacks (e.g. TAA) and chances are there
1889	  will be more of those attacks discovered in the future.
1890
1891	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1892	  might override this decision by tsx=on the command line parameter.
1893	  Even with TSX enabled, the kernel will attempt to enable the best
1894	  possible TAA mitigation setting depending on the microcode available
1895	  for the particular machine.
1896
1897	  This option allows to set the default tsx mode between tsx=on, =off
1898	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1899	  details.
1900
1901	  Say off if not sure, auto if TSX is in use but it should be used on safe
1902	  platforms or on if TSX is in use and the security aspect of tsx is not
1903	  relevant.
1904
1905config X86_INTEL_TSX_MODE_OFF
1906	bool "off"
1907	help
1908	  TSX is disabled if possible - equals to tsx=off command line parameter.
1909
1910config X86_INTEL_TSX_MODE_ON
1911	bool "on"
1912	help
1913	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1914	  line parameter.
1915
1916config X86_INTEL_TSX_MODE_AUTO
1917	bool "auto"
1918	help
1919	  TSX is enabled on TSX capable HW that is believed to be safe against
1920	  side channel attacks- equals the tsx=auto command line parameter.
1921endchoice
1922
1923config X86_SGX
1924	bool "Software Guard eXtensions (SGX)"
1925	depends on X86_64 && CPU_SUP_INTEL
1926	depends on CRYPTO=y
1927	depends on CRYPTO_SHA256=y
1928	select SRCU
1929	select MMU_NOTIFIER
1930	select NUMA_KEEP_MEMINFO if NUMA
1931	select XARRAY_MULTI
1932	help
1933	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1934	  that can be used by applications to set aside private regions of code
1935	  and data, referred to as enclaves. An enclave's private memory can
1936	  only be accessed by code running within the enclave. Accesses from
1937	  outside the enclave, including other enclaves, are disallowed by
1938	  hardware.
1939
1940	  If unsure, say N.
1941
1942config EFI
1943	bool "EFI runtime service support"
1944	depends on ACPI
1945	select UCS2_STRING
1946	select EFI_RUNTIME_WRAPPERS
1947	select ARCH_USE_MEMREMAP_PROT
1948	help
1949	  This enables the kernel to use EFI runtime services that are
1950	  available (such as the EFI variable services).
1951
1952	  This option is only useful on systems that have EFI firmware.
1953	  In addition, you should use the latest ELILO loader available
1954	  at <http://elilo.sourceforge.net> in order to take advantage
1955	  of EFI runtime services. However, even with this option, the
1956	  resultant kernel should continue to boot on existing non-EFI
1957	  platforms.
1958
1959config EFI_STUB
1960	bool "EFI stub support"
1961	depends on EFI
1962	depends on $(cc-option,-mabi=ms) || X86_32
1963	select RELOCATABLE
1964	help
1965	  This kernel feature allows a bzImage to be loaded directly
1966	  by EFI firmware without the use of a bootloader.
1967
1968	  See Documentation/admin-guide/efi-stub.rst for more information.
1969
1970config EFI_MIXED
1971	bool "EFI mixed-mode support"
1972	depends on EFI_STUB && X86_64
1973	help
1974	   Enabling this feature allows a 64-bit kernel to be booted
1975	   on a 32-bit firmware, provided that your CPU supports 64-bit
1976	   mode.
1977
1978	   Note that it is not possible to boot a mixed-mode enabled
1979	   kernel via the EFI boot stub - a bootloader that supports
1980	   the EFI handover protocol must be used.
1981
1982	   If unsure, say N.
1983
1984source "kernel/Kconfig.hz"
1985
1986config KEXEC
1987	bool "kexec system call"
1988	select KEXEC_CORE
1989	help
1990	  kexec is a system call that implements the ability to shutdown your
1991	  current kernel, and to start another kernel.  It is like a reboot
1992	  but it is independent of the system firmware.   And like a reboot
1993	  you can start any kernel with it, not just Linux.
1994
1995	  The name comes from the similarity to the exec system call.
1996
1997	  It is an ongoing process to be certain the hardware in a machine
1998	  is properly shutdown, so do not be surprised if this code does not
1999	  initially work for you.  As of this writing the exact hardware
2000	  interface is strongly in flux, so no good recommendation can be
2001	  made.
2002
2003config KEXEC_FILE
2004	bool "kexec file based system call"
2005	select KEXEC_CORE
2006	select BUILD_BIN2C
2007	depends on X86_64
2008	depends on CRYPTO=y
2009	depends on CRYPTO_SHA256=y
2010	help
2011	  This is new version of kexec system call. This system call is
2012	  file based and takes file descriptors as system call argument
2013	  for kernel and initramfs as opposed to list of segments as
2014	  accepted by previous system call.
2015
2016config ARCH_HAS_KEXEC_PURGATORY
2017	def_bool KEXEC_FILE
2018
2019config KEXEC_SIG
2020	bool "Verify kernel signature during kexec_file_load() syscall"
2021	depends on KEXEC_FILE
2022	help
2023
2024	  This option makes the kexec_file_load() syscall check for a valid
2025	  signature of the kernel image.  The image can still be loaded without
2026	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2027	  there's a signature that we can check, then it must be valid.
2028
2029	  In addition to this option, you need to enable signature
2030	  verification for the corresponding kernel image type being
2031	  loaded in order for this to work.
2032
2033config KEXEC_SIG_FORCE
2034	bool "Require a valid signature in kexec_file_load() syscall"
2035	depends on KEXEC_SIG
2036	help
2037	  This option makes kernel signature verification mandatory for
2038	  the kexec_file_load() syscall.
2039
2040config KEXEC_BZIMAGE_VERIFY_SIG
2041	bool "Enable bzImage signature verification support"
2042	depends on KEXEC_SIG
2043	depends on SIGNED_PE_FILE_VERIFICATION
2044	select SYSTEM_TRUSTED_KEYRING
2045	help
2046	  Enable bzImage signature verification support.
2047
2048config CRASH_DUMP
2049	bool "kernel crash dumps"
2050	depends on X86_64 || (X86_32 && HIGHMEM)
2051	help
2052	  Generate crash dump after being started by kexec.
2053	  This should be normally only set in special crash dump kernels
2054	  which are loaded in the main kernel with kexec-tools into
2055	  a specially reserved region and then later executed after
2056	  a crash by kdump/kexec. The crash dump kernel must be compiled
2057	  to a memory address not used by the main kernel or BIOS using
2058	  PHYSICAL_START, or it must be built as a relocatable image
2059	  (CONFIG_RELOCATABLE=y).
2060	  For more details see Documentation/admin-guide/kdump/kdump.rst
2061
2062config KEXEC_JUMP
2063	bool "kexec jump"
2064	depends on KEXEC && HIBERNATION
2065	help
2066	  Jump between original kernel and kexeced kernel and invoke
2067	  code in physical address mode via KEXEC
2068
2069config PHYSICAL_START
2070	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2071	default "0x1000000"
2072	help
2073	  This gives the physical address where the kernel is loaded.
2074
2075	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2076	  bzImage will decompress itself to above physical address and
2077	  run from there. Otherwise, bzImage will run from the address where
2078	  it has been loaded by the boot loader and will ignore above physical
2079	  address.
2080
2081	  In normal kdump cases one does not have to set/change this option
2082	  as now bzImage can be compiled as a completely relocatable image
2083	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2084	  address. This option is mainly useful for the folks who don't want
2085	  to use a bzImage for capturing the crash dump and want to use a
2086	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2087	  to be specifically compiled to run from a specific memory area
2088	  (normally a reserved region) and this option comes handy.
2089
2090	  So if you are using bzImage for capturing the crash dump,
2091	  leave the value here unchanged to 0x1000000 and set
2092	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2093	  for capturing the crash dump change this value to start of
2094	  the reserved region.  In other words, it can be set based on
2095	  the "X" value as specified in the "crashkernel=YM@XM"
2096	  command line boot parameter passed to the panic-ed
2097	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2098	  for more details about crash dumps.
2099
2100	  Usage of bzImage for capturing the crash dump is recommended as
2101	  one does not have to build two kernels. Same kernel can be used
2102	  as production kernel and capture kernel. Above option should have
2103	  gone away after relocatable bzImage support is introduced. But it
2104	  is present because there are users out there who continue to use
2105	  vmlinux for dump capture. This option should go away down the
2106	  line.
2107
2108	  Don't change this unless you know what you are doing.
2109
2110config RELOCATABLE
2111	bool "Build a relocatable kernel"
2112	default y
2113	help
2114	  This builds a kernel image that retains relocation information
2115	  so it can be loaded someplace besides the default 1MB.
2116	  The relocations tend to make the kernel binary about 10% larger,
2117	  but are discarded at runtime.
2118
2119	  One use is for the kexec on panic case where the recovery kernel
2120	  must live at a different physical address than the primary
2121	  kernel.
2122
2123	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2124	  it has been loaded at and the compile time physical address
2125	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2126
2127config RANDOMIZE_BASE
2128	bool "Randomize the address of the kernel image (KASLR)"
2129	depends on RELOCATABLE
2130	default y
2131	help
2132	  In support of Kernel Address Space Layout Randomization (KASLR),
2133	  this randomizes the physical address at which the kernel image
2134	  is decompressed and the virtual address where the kernel
2135	  image is mapped, as a security feature that deters exploit
2136	  attempts relying on knowledge of the location of kernel
2137	  code internals.
2138
2139	  On 64-bit, the kernel physical and virtual addresses are
2140	  randomized separately. The physical address will be anywhere
2141	  between 16MB and the top of physical memory (up to 64TB). The
2142	  virtual address will be randomized from 16MB up to 1GB (9 bits
2143	  of entropy). Note that this also reduces the memory space
2144	  available to kernel modules from 1.5GB to 1GB.
2145
2146	  On 32-bit, the kernel physical and virtual addresses are
2147	  randomized together. They will be randomized from 16MB up to
2148	  512MB (8 bits of entropy).
2149
2150	  Entropy is generated using the RDRAND instruction if it is
2151	  supported. If RDTSC is supported, its value is mixed into
2152	  the entropy pool as well. If neither RDRAND nor RDTSC are
2153	  supported, then entropy is read from the i8254 timer. The
2154	  usable entropy is limited by the kernel being built using
2155	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2156	  minimum of 2MB. As a result, only 10 bits of entropy are
2157	  theoretically possible, but the implementations are further
2158	  limited due to memory layouts.
2159
2160	  If unsure, say Y.
2161
2162# Relocation on x86 needs some additional build support
2163config X86_NEED_RELOCS
2164	def_bool y
2165	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2166
2167config PHYSICAL_ALIGN
2168	hex "Alignment value to which kernel should be aligned"
2169	default "0x200000"
2170	range 0x2000 0x1000000 if X86_32
2171	range 0x200000 0x1000000 if X86_64
2172	help
2173	  This value puts the alignment restrictions on physical address
2174	  where kernel is loaded and run from. Kernel is compiled for an
2175	  address which meets above alignment restriction.
2176
2177	  If bootloader loads the kernel at a non-aligned address and
2178	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2179	  address aligned to above value and run from there.
2180
2181	  If bootloader loads the kernel at a non-aligned address and
2182	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2183	  load address and decompress itself to the address it has been
2184	  compiled for and run from there. The address for which kernel is
2185	  compiled already meets above alignment restrictions. Hence the
2186	  end result is that kernel runs from a physical address meeting
2187	  above alignment restrictions.
2188
2189	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2190	  this value must be a multiple of 0x200000.
2191
2192	  Don't change this unless you know what you are doing.
2193
2194config DYNAMIC_MEMORY_LAYOUT
2195	bool
2196	help
2197	  This option makes base addresses of vmalloc and vmemmap as well as
2198	  __PAGE_OFFSET movable during boot.
2199
2200config RANDOMIZE_MEMORY
2201	bool "Randomize the kernel memory sections"
2202	depends on X86_64
2203	depends on RANDOMIZE_BASE
2204	select DYNAMIC_MEMORY_LAYOUT
2205	default RANDOMIZE_BASE
2206	help
2207	   Randomizes the base virtual address of kernel memory sections
2208	   (physical memory mapping, vmalloc & vmemmap). This security feature
2209	   makes exploits relying on predictable memory locations less reliable.
2210
2211	   The order of allocations remains unchanged. Entropy is generated in
2212	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2213	   configuration have in average 30,000 different possible virtual
2214	   addresses for each memory section.
2215
2216	   If unsure, say Y.
2217
2218config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2219	hex "Physical memory mapping padding" if EXPERT
2220	depends on RANDOMIZE_MEMORY
2221	default "0xa" if MEMORY_HOTPLUG
2222	default "0x0"
2223	range 0x1 0x40 if MEMORY_HOTPLUG
2224	range 0x0 0x40
2225	help
2226	   Define the padding in terabytes added to the existing physical
2227	   memory size during kernel memory randomization. It is useful
2228	   for memory hotplug support but reduces the entropy available for
2229	   address randomization.
2230
2231	   If unsure, leave at the default value.
2232
2233config HOTPLUG_CPU
2234	def_bool y
2235	depends on SMP
2236
2237config BOOTPARAM_HOTPLUG_CPU0
2238	bool "Set default setting of cpu0_hotpluggable"
2239	depends on HOTPLUG_CPU
2240	help
2241	  Set whether default state of cpu0_hotpluggable is on or off.
2242
2243	  Say Y here to enable CPU0 hotplug by default. If this switch
2244	  is turned on, there is no need to give cpu0_hotplug kernel
2245	  parameter and the CPU0 hotplug feature is enabled by default.
2246
2247	  Please note: there are two known CPU0 dependencies if you want
2248	  to enable the CPU0 hotplug feature either by this switch or by
2249	  cpu0_hotplug kernel parameter.
2250
2251	  First, resume from hibernate or suspend always starts from CPU0.
2252	  So hibernate and suspend are prevented if CPU0 is offline.
2253
2254	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2255	  offline if any interrupt can not migrate out of CPU0. There may
2256	  be other CPU0 dependencies.
2257
2258	  Please make sure the dependencies are under your control before
2259	  you enable this feature.
2260
2261	  Say N if you don't want to enable CPU0 hotplug feature by default.
2262	  You still can enable the CPU0 hotplug feature at boot by kernel
2263	  parameter cpu0_hotplug.
2264
2265config DEBUG_HOTPLUG_CPU0
2266	def_bool n
2267	prompt "Debug CPU0 hotplug"
2268	depends on HOTPLUG_CPU
2269	help
2270	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2271	  soon as possible and boots up userspace with CPU0 offlined. User
2272	  can online CPU0 back after boot time.
2273
2274	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2275	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2276	  compilation or giving cpu0_hotplug kernel parameter at boot.
2277
2278	  If unsure, say N.
2279
2280config COMPAT_VDSO
2281	def_bool n
2282	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2283	depends on COMPAT_32
2284	help
2285	  Certain buggy versions of glibc will crash if they are
2286	  presented with a 32-bit vDSO that is not mapped at the address
2287	  indicated in its segment table.
2288
2289	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2290	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2291	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2292	  the only released version with the bug, but OpenSUSE 9
2293	  contains a buggy "glibc 2.3.2".
2294
2295	  The symptom of the bug is that everything crashes on startup, saying:
2296	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2297
2298	  Saying Y here changes the default value of the vdso32 boot
2299	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2300	  This works around the glibc bug but hurts performance.
2301
2302	  If unsure, say N: if you are compiling your own kernel, you
2303	  are unlikely to be using a buggy version of glibc.
2304
2305choice
2306	prompt "vsyscall table for legacy applications"
2307	depends on X86_64
2308	default LEGACY_VSYSCALL_XONLY
2309	help
2310	  Legacy user code that does not know how to find the vDSO expects
2311	  to be able to issue three syscalls by calling fixed addresses in
2312	  kernel space. Since this location is not randomized with ASLR,
2313	  it can be used to assist security vulnerability exploitation.
2314
2315	  This setting can be changed at boot time via the kernel command
2316	  line parameter vsyscall=[emulate|xonly|none].
2317
2318	  On a system with recent enough glibc (2.14 or newer) and no
2319	  static binaries, you can say None without a performance penalty
2320	  to improve security.
2321
2322	  If unsure, select "Emulate execution only".
2323
2324	config LEGACY_VSYSCALL_EMULATE
2325		bool "Full emulation"
2326		help
2327		  The kernel traps and emulates calls into the fixed vsyscall
2328		  address mapping. This makes the mapping non-executable, but
2329		  it still contains readable known contents, which could be
2330		  used in certain rare security vulnerability exploits. This
2331		  configuration is recommended when using legacy userspace
2332		  that still uses vsyscalls along with legacy binary
2333		  instrumentation tools that require code to be readable.
2334
2335		  An example of this type of legacy userspace is running
2336		  Pin on an old binary that still uses vsyscalls.
2337
2338	config LEGACY_VSYSCALL_XONLY
2339		bool "Emulate execution only"
2340		help
2341		  The kernel traps and emulates calls into the fixed vsyscall
2342		  address mapping and does not allow reads.  This
2343		  configuration is recommended when userspace might use the
2344		  legacy vsyscall area but support for legacy binary
2345		  instrumentation of legacy code is not needed.  It mitigates
2346		  certain uses of the vsyscall area as an ASLR-bypassing
2347		  buffer.
2348
2349	config LEGACY_VSYSCALL_NONE
2350		bool "None"
2351		help
2352		  There will be no vsyscall mapping at all. This will
2353		  eliminate any risk of ASLR bypass due to the vsyscall
2354		  fixed address mapping. Attempts to use the vsyscalls
2355		  will be reported to dmesg, so that either old or
2356		  malicious userspace programs can be identified.
2357
2358endchoice
2359
2360config CMDLINE_BOOL
2361	bool "Built-in kernel command line"
2362	help
2363	  Allow for specifying boot arguments to the kernel at
2364	  build time.  On some systems (e.g. embedded ones), it is
2365	  necessary or convenient to provide some or all of the
2366	  kernel boot arguments with the kernel itself (that is,
2367	  to not rely on the boot loader to provide them.)
2368
2369	  To compile command line arguments into the kernel,
2370	  set this option to 'Y', then fill in the
2371	  boot arguments in CONFIG_CMDLINE.
2372
2373	  Systems with fully functional boot loaders (i.e. non-embedded)
2374	  should leave this option set to 'N'.
2375
2376config CMDLINE
2377	string "Built-in kernel command string"
2378	depends on CMDLINE_BOOL
2379	default ""
2380	help
2381	  Enter arguments here that should be compiled into the kernel
2382	  image and used at boot time.  If the boot loader provides a
2383	  command line at boot time, it is appended to this string to
2384	  form the full kernel command line, when the system boots.
2385
2386	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2387	  change this behavior.
2388
2389	  In most cases, the command line (whether built-in or provided
2390	  by the boot loader) should specify the device for the root
2391	  file system.
2392
2393config CMDLINE_OVERRIDE
2394	bool "Built-in command line overrides boot loader arguments"
2395	depends on CMDLINE_BOOL && CMDLINE != ""
2396	help
2397	  Set this option to 'Y' to have the kernel ignore the boot loader
2398	  command line, and use ONLY the built-in command line.
2399
2400	  This is used to work around broken boot loaders.  This should
2401	  be set to 'N' under normal conditions.
2402
2403config MODIFY_LDT_SYSCALL
2404	bool "Enable the LDT (local descriptor table)" if EXPERT
2405	default y
2406	help
2407	  Linux can allow user programs to install a per-process x86
2408	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2409	  call.  This is required to run 16-bit or segmented code such as
2410	  DOSEMU or some Wine programs.  It is also used by some very old
2411	  threading libraries.
2412
2413	  Enabling this feature adds a small amount of overhead to
2414	  context switches and increases the low-level kernel attack
2415	  surface.  Disabling it removes the modify_ldt(2) system call.
2416
2417	  Saying 'N' here may make sense for embedded or server kernels.
2418
2419config STRICT_SIGALTSTACK_SIZE
2420	bool "Enforce strict size checking for sigaltstack"
2421	depends on DYNAMIC_SIGFRAME
2422	help
2423	  For historical reasons MINSIGSTKSZ is a constant which became
2424	  already too small with AVX512 support. Add a mechanism to
2425	  enforce strict checking of the sigaltstack size against the
2426	  real size of the FPU frame. This option enables the check
2427	  by default. It can also be controlled via the kernel command
2428	  line option 'strict_sas_size' independent of this config
2429	  switch. Enabling it might break existing applications which
2430	  allocate a too small sigaltstack but 'work' because they
2431	  never get a signal delivered.
2432
2433	  Say 'N' unless you want to really enforce this check.
2434
2435source "kernel/livepatch/Kconfig"
2436
2437endmenu
2438
2439config ARCH_HAS_ADD_PAGES
2440	def_bool y
2441	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2442
2443config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2444	def_bool y
2445
2446menu "Power management and ACPI options"
2447
2448config ARCH_HIBERNATION_HEADER
2449	def_bool y
2450	depends on HIBERNATION
2451
2452source "kernel/power/Kconfig"
2453
2454source "drivers/acpi/Kconfig"
2455
2456config X86_APM_BOOT
2457	def_bool y
2458	depends on APM
2459
2460menuconfig APM
2461	tristate "APM (Advanced Power Management) BIOS support"
2462	depends on X86_32 && PM_SLEEP
2463	help
2464	  APM is a BIOS specification for saving power using several different
2465	  techniques. This is mostly useful for battery powered laptops with
2466	  APM compliant BIOSes. If you say Y here, the system time will be
2467	  reset after a RESUME operation, the /proc/apm device will provide
2468	  battery status information, and user-space programs will receive
2469	  notification of APM "events" (e.g. battery status change).
2470
2471	  If you select "Y" here, you can disable actual use of the APM
2472	  BIOS by passing the "apm=off" option to the kernel at boot time.
2473
2474	  Note that the APM support is almost completely disabled for
2475	  machines with more than one CPU.
2476
2477	  In order to use APM, you will need supporting software. For location
2478	  and more information, read <file:Documentation/power/apm-acpi.rst>
2479	  and the Battery Powered Linux mini-HOWTO, available from
2480	  <http://www.tldp.org/docs.html#howto>.
2481
2482	  This driver does not spin down disk drives (see the hdparm(8)
2483	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2484	  VESA-compliant "green" monitors.
2485
2486	  This driver does not support the TI 4000M TravelMate and the ACER
2487	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2488	  desktop machines also don't have compliant BIOSes, and this driver
2489	  may cause those machines to panic during the boot phase.
2490
2491	  Generally, if you don't have a battery in your machine, there isn't
2492	  much point in using this driver and you should say N. If you get
2493	  random kernel OOPSes or reboots that don't seem to be related to
2494	  anything, try disabling/enabling this option (or disabling/enabling
2495	  APM in your BIOS).
2496
2497	  Some other things you should try when experiencing seemingly random,
2498	  "weird" problems:
2499
2500	  1) make sure that you have enough swap space and that it is
2501	  enabled.
2502	  2) pass the "no-hlt" option to the kernel
2503	  3) switch on floating point emulation in the kernel and pass
2504	  the "no387" option to the kernel
2505	  4) pass the "floppy=nodma" option to the kernel
2506	  5) pass the "mem=4M" option to the kernel (thereby disabling
2507	  all but the first 4 MB of RAM)
2508	  6) make sure that the CPU is not over clocked.
2509	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2510	  8) disable the cache from your BIOS settings
2511	  9) install a fan for the video card or exchange video RAM
2512	  10) install a better fan for the CPU
2513	  11) exchange RAM chips
2514	  12) exchange the motherboard.
2515
2516	  To compile this driver as a module, choose M here: the
2517	  module will be called apm.
2518
2519if APM
2520
2521config APM_IGNORE_USER_SUSPEND
2522	bool "Ignore USER SUSPEND"
2523	help
2524	  This option will ignore USER SUSPEND requests. On machines with a
2525	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2526	  series notebooks, it is necessary to say Y because of a BIOS bug.
2527
2528config APM_DO_ENABLE
2529	bool "Enable PM at boot time"
2530	help
2531	  Enable APM features at boot time. From page 36 of the APM BIOS
2532	  specification: "When disabled, the APM BIOS does not automatically
2533	  power manage devices, enter the Standby State, enter the Suspend
2534	  State, or take power saving steps in response to CPU Idle calls."
2535	  This driver will make CPU Idle calls when Linux is idle (unless this
2536	  feature is turned off -- see "Do CPU IDLE calls", below). This
2537	  should always save battery power, but more complicated APM features
2538	  will be dependent on your BIOS implementation. You may need to turn
2539	  this option off if your computer hangs at boot time when using APM
2540	  support, or if it beeps continuously instead of suspending. Turn
2541	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2542	  T400CDT. This is off by default since most machines do fine without
2543	  this feature.
2544
2545config APM_CPU_IDLE
2546	depends on CPU_IDLE
2547	bool "Make CPU Idle calls when idle"
2548	help
2549	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2550	  On some machines, this can activate improved power savings, such as
2551	  a slowed CPU clock rate, when the machine is idle. These idle calls
2552	  are made after the idle loop has run for some length of time (e.g.,
2553	  333 mS). On some machines, this will cause a hang at boot time or
2554	  whenever the CPU becomes idle. (On machines with more than one CPU,
2555	  this option does nothing.)
2556
2557config APM_DISPLAY_BLANK
2558	bool "Enable console blanking using APM"
2559	help
2560	  Enable console blanking using the APM. Some laptops can use this to
2561	  turn off the LCD backlight when the screen blanker of the Linux
2562	  virtual console blanks the screen. Note that this is only used by
2563	  the virtual console screen blanker, and won't turn off the backlight
2564	  when using the X Window system. This also doesn't have anything to
2565	  do with your VESA-compliant power-saving monitor. Further, this
2566	  option doesn't work for all laptops -- it might not turn off your
2567	  backlight at all, or it might print a lot of errors to the console,
2568	  especially if you are using gpm.
2569
2570config APM_ALLOW_INTS
2571	bool "Allow interrupts during APM BIOS calls"
2572	help
2573	  Normally we disable external interrupts while we are making calls to
2574	  the APM BIOS as a measure to lessen the effects of a badly behaving
2575	  BIOS implementation.  The BIOS should reenable interrupts if it
2576	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2577	  many of the newer IBM Thinkpads.  If you experience hangs when you
2578	  suspend, try setting this to Y.  Otherwise, say N.
2579
2580endif # APM
2581
2582source "drivers/cpufreq/Kconfig"
2583
2584source "drivers/cpuidle/Kconfig"
2585
2586source "drivers/idle/Kconfig"
2587
2588endmenu
2589
2590
2591menu "Bus options (PCI etc.)"
2592
2593choice
2594	prompt "PCI access mode"
2595	depends on X86_32 && PCI
2596	default PCI_GOANY
2597	help
2598	  On PCI systems, the BIOS can be used to detect the PCI devices and
2599	  determine their configuration. However, some old PCI motherboards
2600	  have BIOS bugs and may crash if this is done. Also, some embedded
2601	  PCI-based systems don't have any BIOS at all. Linux can also try to
2602	  detect the PCI hardware directly without using the BIOS.
2603
2604	  With this option, you can specify how Linux should detect the
2605	  PCI devices. If you choose "BIOS", the BIOS will be used,
2606	  if you choose "Direct", the BIOS won't be used, and if you
2607	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2608	  If you choose "Any", the kernel will try MMCONFIG, then the
2609	  direct access method and falls back to the BIOS if that doesn't
2610	  work. If unsure, go with the default, which is "Any".
2611
2612config PCI_GOBIOS
2613	bool "BIOS"
2614
2615config PCI_GOMMCONFIG
2616	bool "MMConfig"
2617
2618config PCI_GODIRECT
2619	bool "Direct"
2620
2621config PCI_GOOLPC
2622	bool "OLPC XO-1"
2623	depends on OLPC
2624
2625config PCI_GOANY
2626	bool "Any"
2627
2628endchoice
2629
2630config PCI_BIOS
2631	def_bool y
2632	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2633
2634# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2635config PCI_DIRECT
2636	def_bool y
2637	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2638
2639config PCI_MMCONFIG
2640	bool "Support mmconfig PCI config space access" if X86_64
2641	default y
2642	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2643	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2644
2645config PCI_OLPC
2646	def_bool y
2647	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2648
2649config PCI_XEN
2650	def_bool y
2651	depends on PCI && XEN
2652
2653config MMCONF_FAM10H
2654	def_bool y
2655	depends on X86_64 && PCI_MMCONFIG && ACPI
2656
2657config PCI_CNB20LE_QUIRK
2658	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2659	depends on PCI
2660	help
2661	  Read the PCI windows out of the CNB20LE host bridge. This allows
2662	  PCI hotplug to work on systems with the CNB20LE chipset which do
2663	  not have ACPI.
2664
2665	  There's no public spec for this chipset, and this functionality
2666	  is known to be incomplete.
2667
2668	  You should say N unless you know you need this.
2669
2670config ISA_BUS
2671	bool "ISA bus support on modern systems" if EXPERT
2672	help
2673	  Expose ISA bus device drivers and options available for selection and
2674	  configuration. Enable this option if your target machine has an ISA
2675	  bus. ISA is an older system, displaced by PCI and newer bus
2676	  architectures -- if your target machine is modern, it probably does
2677	  not have an ISA bus.
2678
2679	  If unsure, say N.
2680
2681# x86_64 have no ISA slots, but can have ISA-style DMA.
2682config ISA_DMA_API
2683	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2684	default y
2685	help
2686	  Enables ISA-style DMA support for devices requiring such controllers.
2687	  If unsure, say Y.
2688
2689if X86_32
2690
2691config ISA
2692	bool "ISA support"
2693	help
2694	  Find out whether you have ISA slots on your motherboard.  ISA is the
2695	  name of a bus system, i.e. the way the CPU talks to the other stuff
2696	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2697	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2698	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2699
2700config SCx200
2701	tristate "NatSemi SCx200 support"
2702	help
2703	  This provides basic support for National Semiconductor's
2704	  (now AMD's) Geode processors.  The driver probes for the
2705	  PCI-IDs of several on-chip devices, so its a good dependency
2706	  for other scx200_* drivers.
2707
2708	  If compiled as a module, the driver is named scx200.
2709
2710config SCx200HR_TIMER
2711	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2712	depends on SCx200
2713	default y
2714	help
2715	  This driver provides a clocksource built upon the on-chip
2716	  27MHz high-resolution timer.  Its also a workaround for
2717	  NSC Geode SC-1100's buggy TSC, which loses time when the
2718	  processor goes idle (as is done by the scheduler).  The
2719	  other workaround is idle=poll boot option.
2720
2721config OLPC
2722	bool "One Laptop Per Child support"
2723	depends on !X86_PAE
2724	select GPIOLIB
2725	select OF
2726	select OF_PROMTREE
2727	select IRQ_DOMAIN
2728	select OLPC_EC
2729	help
2730	  Add support for detecting the unique features of the OLPC
2731	  XO hardware.
2732
2733config OLPC_XO1_PM
2734	bool "OLPC XO-1 Power Management"
2735	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2736	help
2737	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2738
2739config OLPC_XO1_RTC
2740	bool "OLPC XO-1 Real Time Clock"
2741	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2742	help
2743	  Add support for the XO-1 real time clock, which can be used as a
2744	  programmable wakeup source.
2745
2746config OLPC_XO1_SCI
2747	bool "OLPC XO-1 SCI extras"
2748	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2749	depends on INPUT=y
2750	select POWER_SUPPLY
2751	help
2752	  Add support for SCI-based features of the OLPC XO-1 laptop:
2753	   - EC-driven system wakeups
2754	   - Power button
2755	   - Ebook switch
2756	   - Lid switch
2757	   - AC adapter status updates
2758	   - Battery status updates
2759
2760config OLPC_XO15_SCI
2761	bool "OLPC XO-1.5 SCI extras"
2762	depends on OLPC && ACPI
2763	select POWER_SUPPLY
2764	help
2765	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2766	   - EC-driven system wakeups
2767	   - AC adapter status updates
2768	   - Battery status updates
2769
2770config ALIX
2771	bool "PCEngines ALIX System Support (LED setup)"
2772	select GPIOLIB
2773	help
2774	  This option enables system support for the PCEngines ALIX.
2775	  At present this just sets up LEDs for GPIO control on
2776	  ALIX2/3/6 boards.  However, other system specific setup should
2777	  get added here.
2778
2779	  Note: You must still enable the drivers for GPIO and LED support
2780	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2781
2782	  Note: You have to set alix.force=1 for boards with Award BIOS.
2783
2784config NET5501
2785	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2786	select GPIOLIB
2787	help
2788	  This option enables system support for the Soekris Engineering net5501.
2789
2790config GEOS
2791	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2792	select GPIOLIB
2793	depends on DMI
2794	help
2795	  This option enables system support for the Traverse Technologies GEOS.
2796
2797config TS5500
2798	bool "Technologic Systems TS-5500 platform support"
2799	depends on MELAN
2800	select CHECK_SIGNATURE
2801	select NEW_LEDS
2802	select LEDS_CLASS
2803	help
2804	  This option enables system support for the Technologic Systems TS-5500.
2805
2806endif # X86_32
2807
2808config AMD_NB
2809	def_bool y
2810	depends on CPU_SUP_AMD && PCI
2811
2812endmenu
2813
2814
2815menu "Binary Emulations"
2816
2817config IA32_EMULATION
2818	bool "IA32 Emulation"
2819	depends on X86_64
2820	select ARCH_WANT_OLD_COMPAT_IPC
2821	select BINFMT_ELF
2822	select COMPAT_OLD_SIGACTION
2823	help
2824	  Include code to run legacy 32-bit programs under a
2825	  64-bit kernel. You should likely turn this on, unless you're
2826	  100% sure that you don't have any 32-bit programs left.
2827
2828config IA32_AOUT
2829	tristate "IA32 a.out support"
2830	depends on IA32_EMULATION
2831	depends on BROKEN
2832	help
2833	  Support old a.out binaries in the 32bit emulation.
2834
2835config X86_X32
2836	bool "x32 ABI for 64-bit mode"
2837	depends on X86_64
2838	help
2839	  Include code to run binaries for the x32 native 32-bit ABI
2840	  for 64-bit processors.  An x32 process gets access to the
2841	  full 64-bit register file and wide data path while leaving
2842	  pointers at 32 bits for smaller memory footprint.
2843
2844	  You will need a recent binutils (2.22 or later) with
2845	  elf32_x86_64 support enabled to compile a kernel with this
2846	  option set.
2847
2848config COMPAT_32
2849	def_bool y
2850	depends on IA32_EMULATION || X86_32
2851	select HAVE_UID16
2852	select OLD_SIGSUSPEND3
2853
2854config COMPAT
2855	def_bool y
2856	depends on IA32_EMULATION || X86_X32
2857
2858if COMPAT
2859config COMPAT_FOR_U64_ALIGNMENT
2860	def_bool y
2861
2862config SYSVIPC_COMPAT
2863	def_bool y
2864	depends on SYSVIPC
2865endif
2866
2867endmenu
2868
2869
2870config HAVE_ATOMIC_IOMAP
2871	def_bool y
2872	depends on X86_32
2873
2874source "arch/x86/kvm/Kconfig"
2875
2876source "arch/x86/Kconfig.assembler"
2877