xref: /openbmc/linux/arch/x86/Kconfig (revision d15cb3da)
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_HUGE_PMD_SHARE
122	select ARCH_WANT_LD_ORPHAN_WARN
123	select ARCH_WANTS_THP_SWAP		if X86_64
124	select ARCH_HAS_PARANOID_L1D_FLUSH
125	select BUILDTIME_TABLE_SORT
126	select CLKEVT_I8253
127	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
128	select CLOCKSOURCE_WATCHDOG
129	select DCACHE_WORD_ACCESS
130	select DYNAMIC_SIGFRAME
131	select EDAC_ATOMIC_SCRUB
132	select EDAC_SUPPORT
133	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
134	select GENERIC_CLOCKEVENTS_MIN_ADJUST
135	select GENERIC_CMOS_UPDATE
136	select GENERIC_CPU_AUTOPROBE
137	select GENERIC_CPU_VULNERABILITIES
138	select GENERIC_EARLY_IOREMAP
139	select GENERIC_ENTRY
140	select GENERIC_IOMAP
141	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
142	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
143	select GENERIC_IRQ_MIGRATION		if SMP
144	select GENERIC_IRQ_PROBE
145	select GENERIC_IRQ_RESERVATION_MODE
146	select GENERIC_IRQ_SHOW
147	select GENERIC_PENDING_IRQ		if SMP
148	select GENERIC_PTDUMP
149	select GENERIC_SMP_IDLE_THREAD
150	select GENERIC_TIME_VSYSCALL
151	select GENERIC_GETTIMEOFDAY
152	select GENERIC_VDSO_TIME_NS
153	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
154	select HARDIRQS_SW_RESEND
155	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
156	select HAVE_ACPI_APEI			if ACPI
157	select HAVE_ACPI_APEI_NMI		if ACPI
158	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
159	select HAVE_ARCH_AUDITSYSCALL
160	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
161	select HAVE_ARCH_JUMP_LABEL
162	select HAVE_ARCH_JUMP_LABEL_RELATIVE
163	select HAVE_ARCH_KASAN			if X86_64
164	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
165	select HAVE_ARCH_KFENCE
166	select HAVE_ARCH_KGDB
167	select HAVE_ARCH_MMAP_RND_BITS		if MMU
168	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
169	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
170	select HAVE_ARCH_PREL32_RELOCATIONS
171	select HAVE_ARCH_SECCOMP_FILTER
172	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
173	select HAVE_ARCH_STACKLEAK
174	select HAVE_ARCH_TRACEHOOK
175	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
176	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
177	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
178	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
179	select HAVE_ARCH_VMAP_STACK		if X86_64
180	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
181	select HAVE_ARCH_WITHIN_STACK_FRAMES
182	select HAVE_ASM_MODVERSIONS
183	select HAVE_CMPXCHG_DOUBLE
184	select HAVE_CMPXCHG_LOCAL
185	select HAVE_CONTEXT_TRACKING		if X86_64
186	select HAVE_CONTEXT_TRACKING_OFFSTACK	if HAVE_CONTEXT_TRACKING
187	select HAVE_C_RECORDMCOUNT
188	select HAVE_OBJTOOL_MCOUNT		if STACK_VALIDATION
189	select HAVE_BUILDTIME_MCOUNT_SORT
190	select HAVE_DEBUG_KMEMLEAK
191	select HAVE_DMA_CONTIGUOUS
192	select HAVE_DYNAMIC_FTRACE
193	select HAVE_DYNAMIC_FTRACE_WITH_REGS
194	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
195	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
196	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
197	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
198	select HAVE_EBPF_JIT
199	select HAVE_EFFICIENT_UNALIGNED_ACCESS
200	select HAVE_EISA
201	select HAVE_EXIT_THREAD
202	select HAVE_FAST_GUP
203	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
204	select HAVE_FTRACE_MCOUNT_RECORD
205	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
206	select HAVE_FUNCTION_TRACER
207	select HAVE_GCC_PLUGINS
208	select HAVE_HW_BREAKPOINT
209	select HAVE_IOREMAP_PROT
210	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
211	select HAVE_IRQ_TIME_ACCOUNTING
212	select HAVE_KERNEL_BZIP2
213	select HAVE_KERNEL_GZIP
214	select HAVE_KERNEL_LZ4
215	select HAVE_KERNEL_LZMA
216	select HAVE_KERNEL_LZO
217	select HAVE_KERNEL_XZ
218	select HAVE_KERNEL_ZSTD
219	select HAVE_KPROBES
220	select HAVE_KPROBES_ON_FTRACE
221	select HAVE_FUNCTION_ERROR_INJECTION
222	select HAVE_KRETPROBES
223	select HAVE_KVM
224	select HAVE_LIVEPATCH			if X86_64
225	select HAVE_MIXED_BREAKPOINTS_REGS
226	select HAVE_MOD_ARCH_SPECIFIC
227	select HAVE_MOVE_PMD
228	select HAVE_MOVE_PUD
229	select HAVE_NMI
230	select HAVE_OPTPROBES
231	select HAVE_PCSPKR_PLATFORM
232	select HAVE_PERF_EVENTS
233	select HAVE_PERF_EVENTS_NMI
234	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
235	select HAVE_PCI
236	select HAVE_PERF_REGS
237	select HAVE_PERF_USER_STACK_DUMP
238	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
239	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
240	select HAVE_REGS_AND_STACK_ACCESS_API
241	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
242	select HAVE_FUNCTION_ARG_ACCESS_API
243	select HAVE_SETUP_PER_CPU_AREA
244	select HAVE_SOFTIRQ_ON_OWN_STACK
245	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
246	select HAVE_STACK_VALIDATION		if X86_64
247	select HAVE_STATIC_CALL
248	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
249	select HAVE_PREEMPT_DYNAMIC
250	select HAVE_RSEQ
251	select HAVE_SYSCALL_TRACEPOINTS
252	select HAVE_UNSTABLE_SCHED_CLOCK
253	select HAVE_USER_RETURN_NOTIFIER
254	select HAVE_GENERIC_VDSO
255	select HOTPLUG_SMT			if SMP
256	select IRQ_FORCED_THREADING
257	select NEED_PER_CPU_EMBED_FIRST_CHUNK
258	select NEED_PER_CPU_PAGE_FIRST_CHUNK
259	select NEED_SG_DMA_LENGTH
260	select PCI_DOMAINS			if PCI
261	select PCI_LOCKLESS_CONFIG		if PCI
262	select PERF_EVENTS
263	select RTC_LIB
264	select RTC_MC146818_LIB
265	select SPARSE_IRQ
266	select SRCU
267	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
268	select SYSCTL_EXCEPTION_TRACE
269	select THREAD_INFO_IN_TASK
270	select TRACE_IRQFLAGS_SUPPORT
271	select USER_STACKTRACE_SUPPORT
272	select VIRT_TO_BUS
273	select HAVE_ARCH_KCSAN			if X86_64
274	select X86_FEATURE_NAMES		if PROC_FS
275	select PROC_PID_ARCH_STATUS		if PROC_FS
276	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
277	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
278
279config INSTRUCTION_DECODER
280	def_bool y
281	depends on KPROBES || PERF_EVENTS || UPROBES
282
283config OUTPUT_FORMAT
284	string
285	default "elf32-i386" if X86_32
286	default "elf64-x86-64" if X86_64
287
288config LOCKDEP_SUPPORT
289	def_bool y
290
291config STACKTRACE_SUPPORT
292	def_bool y
293
294config MMU
295	def_bool y
296
297config ARCH_MMAP_RND_BITS_MIN
298	default 28 if 64BIT
299	default 8
300
301config ARCH_MMAP_RND_BITS_MAX
302	default 32 if 64BIT
303	default 16
304
305config ARCH_MMAP_RND_COMPAT_BITS_MIN
306	default 8
307
308config ARCH_MMAP_RND_COMPAT_BITS_MAX
309	default 16
310
311config SBUS
312	bool
313
314config GENERIC_ISA_DMA
315	def_bool y
316	depends on ISA_DMA_API
317
318config GENERIC_BUG
319	def_bool y
320	depends on BUG
321	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
322
323config GENERIC_BUG_RELATIVE_POINTERS
324	bool
325
326config ARCH_MAY_HAVE_PC_FDC
327	def_bool y
328	depends on ISA_DMA_API
329
330config GENERIC_CALIBRATE_DELAY
331	def_bool y
332
333config ARCH_HAS_CPU_RELAX
334	def_bool y
335
336config ARCH_HAS_FILTER_PGPROT
337	def_bool y
338
339config ARCH_HIBERNATION_POSSIBLE
340	def_bool y
341
342config ARCH_NR_GPIO
343	int
344	default 1024 if X86_64
345	default 512
346
347config ARCH_SUSPEND_POSSIBLE
348	def_bool y
349
350config ARCH_WANT_GENERAL_HUGETLB
351	def_bool y
352
353config AUDIT_ARCH
354	def_bool y if X86_64
355
356config KASAN_SHADOW_OFFSET
357	hex
358	depends on KASAN
359	default 0xdffffc0000000000
360
361config HAVE_INTEL_TXT
362	def_bool y
363	depends on INTEL_IOMMU && ACPI
364
365config X86_32_SMP
366	def_bool y
367	depends on X86_32 && SMP
368
369config X86_64_SMP
370	def_bool y
371	depends on X86_64 && SMP
372
373config ARCH_SUPPORTS_UPROBES
374	def_bool y
375
376config FIX_EARLYCON_MEM
377	def_bool y
378
379config DYNAMIC_PHYSICAL_MASK
380	bool
381
382config PGTABLE_LEVELS
383	int
384	default 5 if X86_5LEVEL
385	default 4 if X86_64
386	default 3 if X86_PAE
387	default 2
388
389config CC_HAS_SANE_STACKPROTECTOR
390	bool
391	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
392	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
393	help
394	   We have to make sure stack protector is unconditionally disabled if
395	   the compiler produces broken code or if it does not let us control
396	   the segment on 32-bit kernels.
397
398menu "Processor type and features"
399
400config SMP
401	bool "Symmetric multi-processing support"
402	help
403	  This enables support for systems with more than one CPU. If you have
404	  a system with only one CPU, say N. If you have a system with more
405	  than one CPU, say Y.
406
407	  If you say N here, the kernel will run on uni- and multiprocessor
408	  machines, but will use only one CPU of a multiprocessor machine. If
409	  you say Y here, the kernel will run on many, but not all,
410	  uniprocessor machines. On a uniprocessor machine, the kernel
411	  will run faster if you say N here.
412
413	  Note that if you say Y here and choose architecture "586" or
414	  "Pentium" under "Processor family", the kernel will not work on 486
415	  architectures. Similarly, multiprocessor kernels for the "PPro"
416	  architecture may not work on all Pentium based boards.
417
418	  People using multiprocessor machines who say Y here should also say
419	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
420	  Management" code will be disabled if you say Y here.
421
422	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
423	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
424	  <http://www.tldp.org/docs.html#howto>.
425
426	  If you don't know what to do here, say N.
427
428config X86_FEATURE_NAMES
429	bool "Processor feature human-readable names" if EMBEDDED
430	default y
431	help
432	  This option compiles in a table of x86 feature bits and corresponding
433	  names.  This is required to support /proc/cpuinfo and a few kernel
434	  messages.  You can disable this to save space, at the expense of
435	  making those few kernel messages show numeric feature bits instead.
436
437	  If in doubt, say Y.
438
439config X86_X2APIC
440	bool "Support x2apic"
441	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
442	help
443	  This enables x2apic support on CPUs that have this feature.
444
445	  This allows 32-bit apic IDs (so it can support very large systems),
446	  and accesses the local apic via MSRs not via mmio.
447
448	  If you don't know what to do here, say N.
449
450config X86_MPPARSE
451	bool "Enable MPS table" if ACPI
452	default y
453	depends on X86_LOCAL_APIC
454	help
455	  For old smp systems that do not have proper acpi support. Newer systems
456	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
457
458config GOLDFISH
459	def_bool y
460	depends on X86_GOLDFISH
461
462config RETPOLINE
463	bool "Avoid speculative indirect branches in kernel"
464	default y
465	help
466	  Compile kernel with the retpoline compiler options to guard against
467	  kernel-to-user data leaks by avoiding speculative indirect
468	  branches. Requires a compiler with -mindirect-branch=thunk-extern
469	  support for full protection. The kernel may run slower.
470
471config CC_HAS_SLS
472	def_bool $(cc-option,-mharden-sls=all)
473
474config SLS
475	bool "Mitigate Straight-Line-Speculation"
476	depends on CC_HAS_SLS && X86_64
477	default n
478	help
479	  Compile the kernel with straight-line-speculation options to guard
480	  against straight line speculation. The kernel image might be slightly
481	  larger.
482
483config X86_CPU_RESCTRL
484	bool "x86 CPU resource control support"
485	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
486	select KERNFS
487	select PROC_CPU_RESCTRL		if PROC_FS
488	help
489	  Enable x86 CPU resource control support.
490
491	  Provide support for the allocation and monitoring of system resources
492	  usage by the CPU.
493
494	  Intel calls this Intel Resource Director Technology
495	  (Intel(R) RDT). More information about RDT can be found in the
496	  Intel x86 Architecture Software Developer Manual.
497
498	  AMD calls this AMD Platform Quality of Service (AMD QoS).
499	  More information about AMD QoS can be found in the AMD64 Technology
500	  Platform Quality of Service Extensions manual.
501
502	  Say N if unsure.
503
504if X86_32
505config X86_BIGSMP
506	bool "Support for big SMP systems with more than 8 CPUs"
507	depends on SMP
508	help
509	  This option is needed for the systems that have more than 8 CPUs.
510
511config X86_EXTENDED_PLATFORM
512	bool "Support for extended (non-PC) x86 platforms"
513	default y
514	help
515	  If you disable this option then the kernel will only support
516	  standard PC platforms. (which covers the vast majority of
517	  systems out there.)
518
519	  If you enable this option then you'll be able to select support
520	  for the following (non-PC) 32 bit x86 platforms:
521		Goldfish (Android emulator)
522		AMD Elan
523		RDC R-321x SoC
524		SGI 320/540 (Visual Workstation)
525		STA2X11-based (e.g. Northville)
526		Moorestown MID devices
527
528	  If you have one of these systems, or if you want to build a
529	  generic distribution kernel, say Y here - otherwise say N.
530endif
531
532if X86_64
533config X86_EXTENDED_PLATFORM
534	bool "Support for extended (non-PC) x86 platforms"
535	default y
536	help
537	  If you disable this option then the kernel will only support
538	  standard PC platforms. (which covers the vast majority of
539	  systems out there.)
540
541	  If you enable this option then you'll be able to select support
542	  for the following (non-PC) 64 bit x86 platforms:
543		Numascale NumaChip
544		ScaleMP vSMP
545		SGI Ultraviolet
546
547	  If you have one of these systems, or if you want to build a
548	  generic distribution kernel, say Y here - otherwise say N.
549endif
550# This is an alphabetically sorted list of 64 bit extended platforms
551# Please maintain the alphabetic order if and when there are additions
552config X86_NUMACHIP
553	bool "Numascale NumaChip"
554	depends on X86_64
555	depends on X86_EXTENDED_PLATFORM
556	depends on NUMA
557	depends on SMP
558	depends on X86_X2APIC
559	depends on PCI_MMCONFIG
560	help
561	  Adds support for Numascale NumaChip large-SMP systems. Needed to
562	  enable more than ~168 cores.
563	  If you don't have one of these, you should say N here.
564
565config X86_VSMP
566	bool "ScaleMP vSMP"
567	select HYPERVISOR_GUEST
568	select PARAVIRT
569	depends on X86_64 && PCI
570	depends on X86_EXTENDED_PLATFORM
571	depends on SMP
572	help
573	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
574	  supposed to run on these EM64T-based machines.  Only choose this option
575	  if you have one of these machines.
576
577config X86_UV
578	bool "SGI Ultraviolet"
579	depends on X86_64
580	depends on X86_EXTENDED_PLATFORM
581	depends on NUMA
582	depends on EFI
583	depends on KEXEC_CORE
584	depends on X86_X2APIC
585	depends on PCI
586	help
587	  This option is needed in order to support SGI Ultraviolet systems.
588	  If you don't have one of these, you should say N here.
589
590# Following is an alphabetically sorted list of 32 bit extended platforms
591# Please maintain the alphabetic order if and when there are additions
592
593config X86_GOLDFISH
594	bool "Goldfish (Virtual Platform)"
595	depends on X86_EXTENDED_PLATFORM
596	help
597	 Enable support for the Goldfish virtual platform used primarily
598	 for Android development. Unless you are building for the Android
599	 Goldfish emulator say N here.
600
601config X86_INTEL_CE
602	bool "CE4100 TV platform"
603	depends on PCI
604	depends on PCI_GODIRECT
605	depends on X86_IO_APIC
606	depends on X86_32
607	depends on X86_EXTENDED_PLATFORM
608	select X86_REBOOTFIXUPS
609	select OF
610	select OF_EARLY_FLATTREE
611	help
612	  Select for the Intel CE media processor (CE4100) SOC.
613	  This option compiles in support for the CE4100 SOC for settop
614	  boxes and media devices.
615
616config X86_INTEL_MID
617	bool "Intel MID platform support"
618	depends on X86_EXTENDED_PLATFORM
619	depends on X86_PLATFORM_DEVICES
620	depends on PCI
621	depends on X86_64 || (PCI_GOANY && X86_32)
622	depends on X86_IO_APIC
623	select I2C
624	select DW_APB_TIMER
625	select INTEL_SCU_PCI
626	help
627	  Select to build a kernel capable of supporting Intel MID (Mobile
628	  Internet Device) platform systems which do not have the PCI legacy
629	  interfaces. If you are building for a PC class system say N here.
630
631	  Intel MID platforms are based on an Intel processor and chipset which
632	  consume less power than most of the x86 derivatives.
633
634config X86_INTEL_QUARK
635	bool "Intel Quark platform support"
636	depends on X86_32
637	depends on X86_EXTENDED_PLATFORM
638	depends on X86_PLATFORM_DEVICES
639	depends on X86_TSC
640	depends on PCI
641	depends on PCI_GOANY
642	depends on X86_IO_APIC
643	select IOSF_MBI
644	select INTEL_IMR
645	select COMMON_CLK
646	help
647	  Select to include support for Quark X1000 SoC.
648	  Say Y here if you have a Quark based system such as the Arduino
649	  compatible Intel Galileo.
650
651config X86_INTEL_LPSS
652	bool "Intel Low Power Subsystem Support"
653	depends on X86 && ACPI && PCI
654	select COMMON_CLK
655	select PINCTRL
656	select IOSF_MBI
657	help
658	  Select to build support for Intel Low Power Subsystem such as
659	  found on Intel Lynxpoint PCH. Selecting this option enables
660	  things like clock tree (common clock framework) and pincontrol
661	  which are needed by the LPSS peripheral drivers.
662
663config X86_AMD_PLATFORM_DEVICE
664	bool "AMD ACPI2Platform devices support"
665	depends on ACPI
666	select COMMON_CLK
667	select PINCTRL
668	help
669	  Select to interpret AMD specific ACPI device to platform device
670	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
671	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
672	  implemented under PINCTRL subsystem.
673
674config IOSF_MBI
675	tristate "Intel SoC IOSF Sideband support for SoC platforms"
676	depends on PCI
677	help
678	  This option enables sideband register access support for Intel SoC
679	  platforms. On these platforms the IOSF sideband is used in lieu of
680	  MSR's for some register accesses, mostly but not limited to thermal
681	  and power. Drivers may query the availability of this device to
682	  determine if they need the sideband in order to work on these
683	  platforms. The sideband is available on the following SoC products.
684	  This list is not meant to be exclusive.
685	   - BayTrail
686	   - Braswell
687	   - Quark
688
689	  You should say Y if you are running a kernel on one of these SoC's.
690
691config IOSF_MBI_DEBUG
692	bool "Enable IOSF sideband access through debugfs"
693	depends on IOSF_MBI && DEBUG_FS
694	help
695	  Select this option to expose the IOSF sideband access registers (MCR,
696	  MDR, MCRX) through debugfs to write and read register information from
697	  different units on the SoC. This is most useful for obtaining device
698	  state information for debug and analysis. As this is a general access
699	  mechanism, users of this option would have specific knowledge of the
700	  device they want to access.
701
702	  If you don't require the option or are in doubt, say N.
703
704config X86_RDC321X
705	bool "RDC R-321x SoC"
706	depends on X86_32
707	depends on X86_EXTENDED_PLATFORM
708	select M486
709	select X86_REBOOTFIXUPS
710	help
711	  This option is needed for RDC R-321x system-on-chip, also known
712	  as R-8610-(G).
713	  If you don't have one of these chips, you should say N here.
714
715config X86_32_NON_STANDARD
716	bool "Support non-standard 32-bit SMP architectures"
717	depends on X86_32 && SMP
718	depends on X86_EXTENDED_PLATFORM
719	help
720	  This option compiles in the bigsmp and STA2X11 default
721	  subarchitectures.  It is intended for a generic binary
722	  kernel. If you select them all, kernel will probe it one by
723	  one and will fallback to default.
724
725# Alphabetically sorted list of Non standard 32 bit platforms
726
727config X86_SUPPORTS_MEMORY_FAILURE
728	def_bool y
729	# MCE code calls memory_failure():
730	depends on X86_MCE
731	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
732	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
733	depends on X86_64 || !SPARSEMEM
734	select ARCH_SUPPORTS_MEMORY_FAILURE
735
736config STA2X11
737	bool "STA2X11 Companion Chip Support"
738	depends on X86_32_NON_STANDARD && PCI
739	select SWIOTLB
740	select MFD_STA2X11
741	select GPIOLIB
742	help
743	  This adds support for boards based on the STA2X11 IO-Hub,
744	  a.k.a. "ConneXt". The chip is used in place of the standard
745	  PC chipset, so all "standard" peripherals are missing. If this
746	  option is selected the kernel will still be able to boot on
747	  standard PC machines.
748
749config X86_32_IRIS
750	tristate "Eurobraille/Iris poweroff module"
751	depends on X86_32
752	help
753	  The Iris machines from EuroBraille do not have APM or ACPI support
754	  to shut themselves down properly.  A special I/O sequence is
755	  needed to do so, which is what this module does at
756	  kernel shutdown.
757
758	  This is only for Iris machines from EuroBraille.
759
760	  If unused, say N.
761
762config SCHED_OMIT_FRAME_POINTER
763	def_bool y
764	prompt "Single-depth WCHAN output"
765	depends on X86
766	help
767	  Calculate simpler /proc/<PID>/wchan values. If this option
768	  is disabled then wchan values will recurse back to the
769	  caller function. This provides more accurate wchan values,
770	  at the expense of slightly more scheduling overhead.
771
772	  If in doubt, say "Y".
773
774menuconfig HYPERVISOR_GUEST
775	bool "Linux guest support"
776	help
777	  Say Y here to enable options for running Linux under various hyper-
778	  visors. This option enables basic hypervisor detection and platform
779	  setup.
780
781	  If you say N, all options in this submenu will be skipped and
782	  disabled, and Linux guest support won't be built in.
783
784if HYPERVISOR_GUEST
785
786config PARAVIRT
787	bool "Enable paravirtualization code"
788	depends on HAVE_STATIC_CALL
789	help
790	  This changes the kernel so it can modify itself when it is run
791	  under a hypervisor, potentially improving performance significantly
792	  over full virtualization.  However, when run without a hypervisor
793	  the kernel is theoretically slower and slightly larger.
794
795config PARAVIRT_XXL
796	bool
797
798config PARAVIRT_DEBUG
799	bool "paravirt-ops debugging"
800	depends on PARAVIRT && DEBUG_KERNEL
801	help
802	  Enable to debug paravirt_ops internals.  Specifically, BUG if
803	  a paravirt_op is missing when it is called.
804
805config PARAVIRT_SPINLOCKS
806	bool "Paravirtualization layer for spinlocks"
807	depends on PARAVIRT && SMP
808	help
809	  Paravirtualized spinlocks allow a pvops backend to replace the
810	  spinlock implementation with something virtualization-friendly
811	  (for example, block the virtual CPU rather than spinning).
812
813	  It has a minimal impact on native kernels and gives a nice performance
814	  benefit on paravirtualized KVM / Xen kernels.
815
816	  If you are unsure how to answer this question, answer Y.
817
818config X86_HV_CALLBACK_VECTOR
819	def_bool n
820
821source "arch/x86/xen/Kconfig"
822
823config KVM_GUEST
824	bool "KVM Guest support (including kvmclock)"
825	depends on PARAVIRT
826	select PARAVIRT_CLOCK
827	select ARCH_CPUIDLE_HALTPOLL
828	select X86_HV_CALLBACK_VECTOR
829	default y
830	help
831	  This option enables various optimizations for running under the KVM
832	  hypervisor. It includes a paravirtualized clock, so that instead
833	  of relying on a PIT (or probably other) emulation by the
834	  underlying device model, the host provides the guest with
835	  timing infrastructure such as time of day, and system time
836
837config ARCH_CPUIDLE_HALTPOLL
838	def_bool n
839	prompt "Disable host haltpoll when loading haltpoll driver"
840	help
841	  If virtualized under KVM, disable host haltpoll.
842
843config PVH
844	bool "Support for running PVH guests"
845	help
846	  This option enables the PVH entry point for guest virtual machines
847	  as specified in the x86/HVM direct boot ABI.
848
849config PARAVIRT_TIME_ACCOUNTING
850	bool "Paravirtual steal time accounting"
851	depends on PARAVIRT
852	help
853	  Select this option to enable fine granularity task steal time
854	  accounting. Time spent executing other tasks in parallel with
855	  the current vCPU is discounted from the vCPU power. To account for
856	  that, there can be a small performance impact.
857
858	  If in doubt, say N here.
859
860config PARAVIRT_CLOCK
861	bool
862
863config JAILHOUSE_GUEST
864	bool "Jailhouse non-root cell support"
865	depends on X86_64 && PCI
866	select X86_PM_TIMER
867	help
868	  This option allows to run Linux as guest in a Jailhouse non-root
869	  cell. You can leave this option disabled if you only want to start
870	  Jailhouse and run Linux afterwards in the root cell.
871
872config ACRN_GUEST
873	bool "ACRN Guest support"
874	depends on X86_64
875	select X86_HV_CALLBACK_VECTOR
876	help
877	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
878	  a flexible, lightweight reference open-source hypervisor, built with
879	  real-time and safety-criticality in mind. It is built for embedded
880	  IOT with small footprint and real-time features. More details can be
881	  found in https://projectacrn.org/.
882
883endif #HYPERVISOR_GUEST
884
885source "arch/x86/Kconfig.cpu"
886
887config HPET_TIMER
888	def_bool X86_64
889	prompt "HPET Timer Support" if X86_32
890	help
891	  Use the IA-PC HPET (High Precision Event Timer) to manage
892	  time in preference to the PIT and RTC, if a HPET is
893	  present.
894	  HPET is the next generation timer replacing legacy 8254s.
895	  The HPET provides a stable time base on SMP
896	  systems, unlike the TSC, but it is more expensive to access,
897	  as it is off-chip.  The interface used is documented
898	  in the HPET spec, revision 1.
899
900	  You can safely choose Y here.  However, HPET will only be
901	  activated if the platform and the BIOS support this feature.
902	  Otherwise the 8254 will be used for timing services.
903
904	  Choose N to continue using the legacy 8254 timer.
905
906config HPET_EMULATE_RTC
907	def_bool y
908	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
909
910# Mark as expert because too many people got it wrong.
911# The code disables itself when not needed.
912config DMI
913	default y
914	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
915	bool "Enable DMI scanning" if EXPERT
916	help
917	  Enabled scanning of DMI to identify machine quirks. Say Y
918	  here unless you have verified that your setup is not
919	  affected by entries in the DMI blacklist. Required by PNP
920	  BIOS code.
921
922config GART_IOMMU
923	bool "Old AMD GART IOMMU support"
924	select DMA_OPS
925	select IOMMU_HELPER
926	select SWIOTLB
927	depends on X86_64 && PCI && AMD_NB
928	help
929	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
930	  GART based hardware IOMMUs.
931
932	  The GART supports full DMA access for devices with 32-bit access
933	  limitations, on systems with more than 3 GB. This is usually needed
934	  for USB, sound, many IDE/SATA chipsets and some other devices.
935
936	  Newer systems typically have a modern AMD IOMMU, supported via
937	  the CONFIG_AMD_IOMMU=y config option.
938
939	  In normal configurations this driver is only active when needed:
940	  there's more than 3 GB of memory and the system contains a
941	  32-bit limited device.
942
943	  If unsure, say Y.
944
945config MAXSMP
946	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
947	depends on X86_64 && SMP && DEBUG_KERNEL
948	select CPUMASK_OFFSTACK
949	help
950	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
951	  If unsure, say N.
952
953#
954# The maximum number of CPUs supported:
955#
956# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
957# and which can be configured interactively in the
958# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
959#
960# The ranges are different on 32-bit and 64-bit kernels, depending on
961# hardware capabilities and scalability features of the kernel.
962#
963# ( If MAXSMP is enabled we just use the highest possible value and disable
964#   interactive configuration. )
965#
966
967config NR_CPUS_RANGE_BEGIN
968	int
969	default NR_CPUS_RANGE_END if MAXSMP
970	default    1 if !SMP
971	default    2
972
973config NR_CPUS_RANGE_END
974	int
975	depends on X86_32
976	default   64 if  SMP &&  X86_BIGSMP
977	default    8 if  SMP && !X86_BIGSMP
978	default    1 if !SMP
979
980config NR_CPUS_RANGE_END
981	int
982	depends on X86_64
983	default 8192 if  SMP && CPUMASK_OFFSTACK
984	default  512 if  SMP && !CPUMASK_OFFSTACK
985	default    1 if !SMP
986
987config NR_CPUS_DEFAULT
988	int
989	depends on X86_32
990	default   32 if  X86_BIGSMP
991	default    8 if  SMP
992	default    1 if !SMP
993
994config NR_CPUS_DEFAULT
995	int
996	depends on X86_64
997	default 8192 if  MAXSMP
998	default   64 if  SMP
999	default    1 if !SMP
1000
1001config NR_CPUS
1002	int "Maximum number of CPUs" if SMP && !MAXSMP
1003	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1004	default NR_CPUS_DEFAULT
1005	help
1006	  This allows you to specify the maximum number of CPUs which this
1007	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1008	  supported value is 8192, otherwise the maximum value is 512.  The
1009	  minimum value which makes sense is 2.
1010
1011	  This is purely to save memory: each supported CPU adds about 8KB
1012	  to the kernel image.
1013
1014config SCHED_CLUSTER
1015	bool "Cluster scheduler support"
1016	depends on SMP
1017	default y
1018	help
1019	  Cluster scheduler support improves the CPU scheduler's decision
1020	  making when dealing with machines that have clusters of CPUs.
1021	  Cluster usually means a couple of CPUs which are placed closely
1022	  by sharing mid-level caches, last-level cache tags or internal
1023	  busses.
1024
1025config SCHED_SMT
1026	def_bool y if SMP
1027
1028config SCHED_MC
1029	def_bool y
1030	prompt "Multi-core scheduler support"
1031	depends on SMP
1032	help
1033	  Multi-core scheduler support improves the CPU scheduler's decision
1034	  making when dealing with multi-core CPU chips at a cost of slightly
1035	  increased overhead in some places. If unsure say N here.
1036
1037config SCHED_MC_PRIO
1038	bool "CPU core priorities scheduler support"
1039	depends on SCHED_MC && CPU_SUP_INTEL
1040	select X86_INTEL_PSTATE
1041	select CPU_FREQ
1042	default y
1043	help
1044	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1045	  core ordering determined at manufacturing time, which allows
1046	  certain cores to reach higher turbo frequencies (when running
1047	  single threaded workloads) than others.
1048
1049	  Enabling this kernel feature teaches the scheduler about
1050	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1051	  scheduler's CPU selection logic accordingly, so that higher
1052	  overall system performance can be achieved.
1053
1054	  This feature will have no effect on CPUs without this feature.
1055
1056	  If unsure say Y here.
1057
1058config UP_LATE_INIT
1059	def_bool y
1060	depends on !SMP && X86_LOCAL_APIC
1061
1062config X86_UP_APIC
1063	bool "Local APIC support on uniprocessors" if !PCI_MSI
1064	default PCI_MSI
1065	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1066	help
1067	  A local APIC (Advanced Programmable Interrupt Controller) is an
1068	  integrated interrupt controller in the CPU. If you have a single-CPU
1069	  system which has a processor with a local APIC, you can say Y here to
1070	  enable and use it. If you say Y here even though your machine doesn't
1071	  have a local APIC, then the kernel will still run with no slowdown at
1072	  all. The local APIC supports CPU-generated self-interrupts (timer,
1073	  performance counters), and the NMI watchdog which detects hard
1074	  lockups.
1075
1076config X86_UP_IOAPIC
1077	bool "IO-APIC support on uniprocessors"
1078	depends on X86_UP_APIC
1079	help
1080	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1081	  SMP-capable replacement for PC-style interrupt controllers. Most
1082	  SMP systems and many recent uniprocessor systems have one.
1083
1084	  If you have a single-CPU system with an IO-APIC, you can say Y here
1085	  to use it. If you say Y here even though your machine doesn't have
1086	  an IO-APIC, then the kernel will still run with no slowdown at all.
1087
1088config X86_LOCAL_APIC
1089	def_bool y
1090	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1091	select IRQ_DOMAIN_HIERARCHY
1092	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1093
1094config X86_IO_APIC
1095	def_bool y
1096	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1097
1098config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1099	bool "Reroute for broken boot IRQs"
1100	depends on X86_IO_APIC
1101	help
1102	  This option enables a workaround that fixes a source of
1103	  spurious interrupts. This is recommended when threaded
1104	  interrupt handling is used on systems where the generation of
1105	  superfluous "boot interrupts" cannot be disabled.
1106
1107	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1108	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1109	  kernel does during interrupt handling). On chipsets where this
1110	  boot IRQ generation cannot be disabled, this workaround keeps
1111	  the original IRQ line masked so that only the equivalent "boot
1112	  IRQ" is delivered to the CPUs. The workaround also tells the
1113	  kernel to set up the IRQ handler on the boot IRQ line. In this
1114	  way only one interrupt is delivered to the kernel. Otherwise
1115	  the spurious second interrupt may cause the kernel to bring
1116	  down (vital) interrupt lines.
1117
1118	  Only affects "broken" chipsets. Interrupt sharing may be
1119	  increased on these systems.
1120
1121config X86_MCE
1122	bool "Machine Check / overheating reporting"
1123	select GENERIC_ALLOCATOR
1124	default y
1125	help
1126	  Machine Check support allows the processor to notify the
1127	  kernel if it detects a problem (e.g. overheating, data corruption).
1128	  The action the kernel takes depends on the severity of the problem,
1129	  ranging from warning messages to halting the machine.
1130
1131config X86_MCELOG_LEGACY
1132	bool "Support for deprecated /dev/mcelog character device"
1133	depends on X86_MCE
1134	help
1135	  Enable support for /dev/mcelog which is needed by the old mcelog
1136	  userspace logging daemon. Consider switching to the new generation
1137	  rasdaemon solution.
1138
1139config X86_MCE_INTEL
1140	def_bool y
1141	prompt "Intel MCE features"
1142	depends on X86_MCE && X86_LOCAL_APIC
1143	help
1144	   Additional support for intel specific MCE features such as
1145	   the thermal monitor.
1146
1147config X86_MCE_AMD
1148	def_bool y
1149	prompt "AMD MCE features"
1150	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1151	help
1152	   Additional support for AMD specific MCE features such as
1153	   the DRAM Error Threshold.
1154
1155config X86_ANCIENT_MCE
1156	bool "Support for old Pentium 5 / WinChip machine checks"
1157	depends on X86_32 && X86_MCE
1158	help
1159	  Include support for machine check handling on old Pentium 5 or WinChip
1160	  systems. These typically need to be enabled explicitly on the command
1161	  line.
1162
1163config X86_MCE_THRESHOLD
1164	depends on X86_MCE_AMD || X86_MCE_INTEL
1165	def_bool y
1166
1167config X86_MCE_INJECT
1168	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1169	tristate "Machine check injector support"
1170	help
1171	  Provide support for injecting machine checks for testing purposes.
1172	  If you don't know what a machine check is and you don't do kernel
1173	  QA it is safe to say n.
1174
1175source "arch/x86/events/Kconfig"
1176
1177config X86_LEGACY_VM86
1178	bool "Legacy VM86 support"
1179	depends on X86_32
1180	help
1181	  This option allows user programs to put the CPU into V8086
1182	  mode, which is an 80286-era approximation of 16-bit real mode.
1183
1184	  Some very old versions of X and/or vbetool require this option
1185	  for user mode setting.  Similarly, DOSEMU will use it if
1186	  available to accelerate real mode DOS programs.  However, any
1187	  recent version of DOSEMU, X, or vbetool should be fully
1188	  functional even without kernel VM86 support, as they will all
1189	  fall back to software emulation. Nevertheless, if you are using
1190	  a 16-bit DOS program where 16-bit performance matters, vm86
1191	  mode might be faster than emulation and you might want to
1192	  enable this option.
1193
1194	  Note that any app that works on a 64-bit kernel is unlikely to
1195	  need this option, as 64-bit kernels don't, and can't, support
1196	  V8086 mode. This option is also unrelated to 16-bit protected
1197	  mode and is not needed to run most 16-bit programs under Wine.
1198
1199	  Enabling this option increases the complexity of the kernel
1200	  and slows down exception handling a tiny bit.
1201
1202	  If unsure, say N here.
1203
1204config VM86
1205	bool
1206	default X86_LEGACY_VM86
1207
1208config X86_16BIT
1209	bool "Enable support for 16-bit segments" if EXPERT
1210	default y
1211	depends on MODIFY_LDT_SYSCALL
1212	help
1213	  This option is required by programs like Wine to run 16-bit
1214	  protected mode legacy code on x86 processors.  Disabling
1215	  this option saves about 300 bytes on i386, or around 6K text
1216	  plus 16K runtime memory on x86-64,
1217
1218config X86_ESPFIX32
1219	def_bool y
1220	depends on X86_16BIT && X86_32
1221
1222config X86_ESPFIX64
1223	def_bool y
1224	depends on X86_16BIT && X86_64
1225
1226config X86_VSYSCALL_EMULATION
1227	bool "Enable vsyscall emulation" if EXPERT
1228	default y
1229	depends on X86_64
1230	help
1231	 This enables emulation of the legacy vsyscall page.  Disabling
1232	 it is roughly equivalent to booting with vsyscall=none, except
1233	 that it will also disable the helpful warning if a program
1234	 tries to use a vsyscall.  With this option set to N, offending
1235	 programs will just segfault, citing addresses of the form
1236	 0xffffffffff600?00.
1237
1238	 This option is required by many programs built before 2013, and
1239	 care should be used even with newer programs if set to N.
1240
1241	 Disabling this option saves about 7K of kernel size and
1242	 possibly 4K of additional runtime pagetable memory.
1243
1244config X86_IOPL_IOPERM
1245	bool "IOPERM and IOPL Emulation"
1246	default y
1247	help
1248	  This enables the ioperm() and iopl() syscalls which are necessary
1249	  for legacy applications.
1250
1251	  Legacy IOPL support is an overbroad mechanism which allows user
1252	  space aside of accessing all 65536 I/O ports also to disable
1253	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1254	  capabilities and permission from potentially active security
1255	  modules.
1256
1257	  The emulation restricts the functionality of the syscall to
1258	  only allowing the full range I/O port access, but prevents the
1259	  ability to disable interrupts from user space which would be
1260	  granted if the hardware IOPL mechanism would be used.
1261
1262config TOSHIBA
1263	tristate "Toshiba Laptop support"
1264	depends on X86_32
1265	help
1266	  This adds a driver to safely access the System Management Mode of
1267	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1268	  not work on models with a Phoenix BIOS. The System Management Mode
1269	  is used to set the BIOS and power saving options on Toshiba portables.
1270
1271	  For information on utilities to make use of this driver see the
1272	  Toshiba Linux utilities web site at:
1273	  <http://www.buzzard.org.uk/toshiba/>.
1274
1275	  Say Y if you intend to run this kernel on a Toshiba portable.
1276	  Say N otherwise.
1277
1278config I8K
1279	tristate "Dell i8k legacy laptop support"
1280	depends on HWMON
1281	depends on PROC_FS
1282	select SENSORS_DELL_SMM
1283	help
1284	  This option enables legacy /proc/i8k userspace interface in hwmon
1285	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1286	  temperature and allows controlling fan speeds of Dell laptops via
1287	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1288	  it reports also power and hotkey status. For fan speed control is
1289	  needed userspace package i8kutils.
1290
1291	  Say Y if you intend to run this kernel on old Dell laptops or want to
1292	  use userspace package i8kutils.
1293	  Say N otherwise.
1294
1295config X86_REBOOTFIXUPS
1296	bool "Enable X86 board specific fixups for reboot"
1297	depends on X86_32
1298	help
1299	  This enables chipset and/or board specific fixups to be done
1300	  in order to get reboot to work correctly. This is only needed on
1301	  some combinations of hardware and BIOS. The symptom, for which
1302	  this config is intended, is when reboot ends with a stalled/hung
1303	  system.
1304
1305	  Currently, the only fixup is for the Geode machines using
1306	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1307
1308	  Say Y if you want to enable the fixup. Currently, it's safe to
1309	  enable this option even if you don't need it.
1310	  Say N otherwise.
1311
1312config MICROCODE
1313	bool "CPU microcode loading support"
1314	default y
1315	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1316	help
1317	  If you say Y here, you will be able to update the microcode on
1318	  Intel and AMD processors. The Intel support is for the IA32 family,
1319	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1320	  AMD support is for families 0x10 and later. You will obviously need
1321	  the actual microcode binary data itself which is not shipped with
1322	  the Linux kernel.
1323
1324	  The preferred method to load microcode from a detached initrd is described
1325	  in Documentation/x86/microcode.rst. For that you need to enable
1326	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1327	  initrd for microcode blobs.
1328
1329	  In addition, you can build the microcode into the kernel. For that you
1330	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1331	  config option.
1332
1333config MICROCODE_INTEL
1334	bool "Intel microcode loading support"
1335	depends on MICROCODE
1336	default MICROCODE
1337	help
1338	  This options enables microcode patch loading support for Intel
1339	  processors.
1340
1341	  For the current Intel microcode data package go to
1342	  <https://downloadcenter.intel.com> and search for
1343	  'Linux Processor Microcode Data File'.
1344
1345config MICROCODE_AMD
1346	bool "AMD microcode loading support"
1347	depends on MICROCODE
1348	help
1349	  If you select this option, microcode patch loading support for AMD
1350	  processors will be enabled.
1351
1352config MICROCODE_OLD_INTERFACE
1353	bool "Ancient loading interface (DEPRECATED)"
1354	default n
1355	depends on MICROCODE
1356	help
1357	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1358	  which was used by userspace tools like iucode_tool and microcode.ctl.
1359	  It is inadequate because it runs too late to be able to properly
1360	  load microcode on a machine and it needs special tools. Instead, you
1361	  should've switched to the early loading method with the initrd or
1362	  builtin microcode by now: Documentation/x86/microcode.rst
1363
1364config X86_MSR
1365	tristate "/dev/cpu/*/msr - Model-specific register support"
1366	help
1367	  This device gives privileged processes access to the x86
1368	  Model-Specific Registers (MSRs).  It is a character device with
1369	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1370	  MSR accesses are directed to a specific CPU on multi-processor
1371	  systems.
1372
1373config X86_CPUID
1374	tristate "/dev/cpu/*/cpuid - CPU information support"
1375	help
1376	  This device gives processes access to the x86 CPUID instruction to
1377	  be executed on a specific processor.  It is a character device
1378	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1379	  /dev/cpu/31/cpuid.
1380
1381choice
1382	prompt "High Memory Support"
1383	default HIGHMEM4G
1384	depends on X86_32
1385
1386config NOHIGHMEM
1387	bool "off"
1388	help
1389	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1390	  However, the address space of 32-bit x86 processors is only 4
1391	  Gigabytes large. That means that, if you have a large amount of
1392	  physical memory, not all of it can be "permanently mapped" by the
1393	  kernel. The physical memory that's not permanently mapped is called
1394	  "high memory".
1395
1396	  If you are compiling a kernel which will never run on a machine with
1397	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1398	  choice and suitable for most users). This will result in a "3GB/1GB"
1399	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1400	  space and the remaining part of the 4GB virtual memory space is used
1401	  by the kernel to permanently map as much physical memory as
1402	  possible.
1403
1404	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1405	  answer "4GB" here.
1406
1407	  If more than 4 Gigabytes is used then answer "64GB" here. This
1408	  selection turns Intel PAE (Physical Address Extension) mode on.
1409	  PAE implements 3-level paging on IA32 processors. PAE is fully
1410	  supported by Linux, PAE mode is implemented on all recent Intel
1411	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1412	  then the kernel will not boot on CPUs that don't support PAE!
1413
1414	  The actual amount of total physical memory will either be
1415	  auto detected or can be forced by using a kernel command line option
1416	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1417	  your boot loader (lilo or loadlin) about how to pass options to the
1418	  kernel at boot time.)
1419
1420	  If unsure, say "off".
1421
1422config HIGHMEM4G
1423	bool "4GB"
1424	help
1425	  Select this if you have a 32-bit processor and between 1 and 4
1426	  gigabytes of physical RAM.
1427
1428config HIGHMEM64G
1429	bool "64GB"
1430	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1431	select X86_PAE
1432	help
1433	  Select this if you have a 32-bit processor and more than 4
1434	  gigabytes of physical RAM.
1435
1436endchoice
1437
1438choice
1439	prompt "Memory split" if EXPERT
1440	default VMSPLIT_3G
1441	depends on X86_32
1442	help
1443	  Select the desired split between kernel and user memory.
1444
1445	  If the address range available to the kernel is less than the
1446	  physical memory installed, the remaining memory will be available
1447	  as "high memory". Accessing high memory is a little more costly
1448	  than low memory, as it needs to be mapped into the kernel first.
1449	  Note that increasing the kernel address space limits the range
1450	  available to user programs, making the address space there
1451	  tighter.  Selecting anything other than the default 3G/1G split
1452	  will also likely make your kernel incompatible with binary-only
1453	  kernel modules.
1454
1455	  If you are not absolutely sure what you are doing, leave this
1456	  option alone!
1457
1458	config VMSPLIT_3G
1459		bool "3G/1G user/kernel split"
1460	config VMSPLIT_3G_OPT
1461		depends on !X86_PAE
1462		bool "3G/1G user/kernel split (for full 1G low memory)"
1463	config VMSPLIT_2G
1464		bool "2G/2G user/kernel split"
1465	config VMSPLIT_2G_OPT
1466		depends on !X86_PAE
1467		bool "2G/2G user/kernel split (for full 2G low memory)"
1468	config VMSPLIT_1G
1469		bool "1G/3G user/kernel split"
1470endchoice
1471
1472config PAGE_OFFSET
1473	hex
1474	default 0xB0000000 if VMSPLIT_3G_OPT
1475	default 0x80000000 if VMSPLIT_2G
1476	default 0x78000000 if VMSPLIT_2G_OPT
1477	default 0x40000000 if VMSPLIT_1G
1478	default 0xC0000000
1479	depends on X86_32
1480
1481config HIGHMEM
1482	def_bool y
1483	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1484
1485config X86_PAE
1486	bool "PAE (Physical Address Extension) Support"
1487	depends on X86_32 && !HIGHMEM4G
1488	select PHYS_ADDR_T_64BIT
1489	select SWIOTLB
1490	help
1491	  PAE is required for NX support, and furthermore enables
1492	  larger swapspace support for non-overcommit purposes. It
1493	  has the cost of more pagetable lookup overhead, and also
1494	  consumes more pagetable space per process.
1495
1496config X86_5LEVEL
1497	bool "Enable 5-level page tables support"
1498	default y
1499	select DYNAMIC_MEMORY_LAYOUT
1500	select SPARSEMEM_VMEMMAP
1501	depends on X86_64
1502	help
1503	  5-level paging enables access to larger address space:
1504	  upto 128 PiB of virtual address space and 4 PiB of
1505	  physical address space.
1506
1507	  It will be supported by future Intel CPUs.
1508
1509	  A kernel with the option enabled can be booted on machines that
1510	  support 4- or 5-level paging.
1511
1512	  See Documentation/x86/x86_64/5level-paging.rst for more
1513	  information.
1514
1515	  Say N if unsure.
1516
1517config X86_DIRECT_GBPAGES
1518	def_bool y
1519	depends on X86_64
1520	help
1521	  Certain kernel features effectively disable kernel
1522	  linear 1 GB mappings (even if the CPU otherwise
1523	  supports them), so don't confuse the user by printing
1524	  that we have them enabled.
1525
1526config X86_CPA_STATISTICS
1527	bool "Enable statistic for Change Page Attribute"
1528	depends on DEBUG_FS
1529	help
1530	  Expose statistics about the Change Page Attribute mechanism, which
1531	  helps to determine the effectiveness of preserving large and huge
1532	  page mappings when mapping protections are changed.
1533
1534config X86_MEM_ENCRYPT
1535	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1536	select DYNAMIC_PHYSICAL_MASK
1537	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
1538	def_bool n
1539
1540config AMD_MEM_ENCRYPT
1541	bool "AMD Secure Memory Encryption (SME) support"
1542	depends on X86_64 && CPU_SUP_AMD
1543	select DMA_COHERENT_POOL
1544	select ARCH_USE_MEMREMAP_PROT
1545	select INSTRUCTION_DECODER
1546	select ARCH_HAS_CC_PLATFORM
1547	select X86_MEM_ENCRYPT
1548	help
1549	  Say yes to enable support for the encryption of system memory.
1550	  This requires an AMD processor that supports Secure Memory
1551	  Encryption (SME).
1552
1553config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1554	bool "Activate AMD Secure Memory Encryption (SME) by default"
1555	depends on AMD_MEM_ENCRYPT
1556	help
1557	  Say yes to have system memory encrypted by default if running on
1558	  an AMD processor that supports Secure Memory Encryption (SME).
1559
1560	  If set to Y, then the encryption of system memory can be
1561	  deactivated with the mem_encrypt=off command line option.
1562
1563	  If set to N, then the encryption of system memory can be
1564	  activated with the mem_encrypt=on command line option.
1565
1566# Common NUMA Features
1567config NUMA
1568	bool "NUMA Memory Allocation and Scheduler Support"
1569	depends on SMP
1570	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1571	default y if X86_BIGSMP
1572	select USE_PERCPU_NUMA_NODE_ID
1573	help
1574	  Enable NUMA (Non-Uniform Memory Access) support.
1575
1576	  The kernel will try to allocate memory used by a CPU on the
1577	  local memory controller of the CPU and add some more
1578	  NUMA awareness to the kernel.
1579
1580	  For 64-bit this is recommended if the system is Intel Core i7
1581	  (or later), AMD Opteron, or EM64T NUMA.
1582
1583	  For 32-bit this is only needed if you boot a 32-bit
1584	  kernel on a 64-bit NUMA platform.
1585
1586	  Otherwise, you should say N.
1587
1588config AMD_NUMA
1589	def_bool y
1590	prompt "Old style AMD Opteron NUMA detection"
1591	depends on X86_64 && NUMA && PCI
1592	help
1593	  Enable AMD NUMA node topology detection.  You should say Y here if
1594	  you have a multi processor AMD system. This uses an old method to
1595	  read the NUMA configuration directly from the builtin Northbridge
1596	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1597	  which also takes priority if both are compiled in.
1598
1599config X86_64_ACPI_NUMA
1600	def_bool y
1601	prompt "ACPI NUMA detection"
1602	depends on X86_64 && NUMA && ACPI && PCI
1603	select ACPI_NUMA
1604	help
1605	  Enable ACPI SRAT based node topology detection.
1606
1607config NUMA_EMU
1608	bool "NUMA emulation"
1609	depends on NUMA
1610	help
1611	  Enable NUMA emulation. A flat machine will be split
1612	  into virtual nodes when booted with "numa=fake=N", where N is the
1613	  number of nodes. This is only useful for debugging.
1614
1615config NODES_SHIFT
1616	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1617	range 1 10
1618	default "10" if MAXSMP
1619	default "6" if X86_64
1620	default "3"
1621	depends on NUMA
1622	help
1623	  Specify the maximum number of NUMA Nodes available on the target
1624	  system.  Increases memory reserved to accommodate various tables.
1625
1626config ARCH_FLATMEM_ENABLE
1627	def_bool y
1628	depends on X86_32 && !NUMA
1629
1630config ARCH_SPARSEMEM_ENABLE
1631	def_bool y
1632	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1633	select SPARSEMEM_STATIC if X86_32
1634	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1635
1636config ARCH_SPARSEMEM_DEFAULT
1637	def_bool X86_64 || (NUMA && X86_32)
1638
1639config ARCH_SELECT_MEMORY_MODEL
1640	def_bool y
1641	depends on ARCH_SPARSEMEM_ENABLE
1642
1643config ARCH_MEMORY_PROBE
1644	bool "Enable sysfs memory/probe interface"
1645	depends on MEMORY_HOTPLUG
1646	help
1647	  This option enables a sysfs memory/probe interface for testing.
1648	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1649	  If you are unsure how to answer this question, answer N.
1650
1651config ARCH_PROC_KCORE_TEXT
1652	def_bool y
1653	depends on X86_64 && PROC_KCORE
1654
1655config ILLEGAL_POINTER_VALUE
1656	hex
1657	default 0 if X86_32
1658	default 0xdead000000000000 if X86_64
1659
1660config X86_PMEM_LEGACY_DEVICE
1661	bool
1662
1663config X86_PMEM_LEGACY
1664	tristate "Support non-standard NVDIMMs and ADR protected memory"
1665	depends on PHYS_ADDR_T_64BIT
1666	depends on BLK_DEV
1667	select X86_PMEM_LEGACY_DEVICE
1668	select NUMA_KEEP_MEMINFO if NUMA
1669	select LIBNVDIMM
1670	help
1671	  Treat memory marked using the non-standard e820 type of 12 as used
1672	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1673	  The kernel will offer these regions to the 'pmem' driver so
1674	  they can be used for persistent storage.
1675
1676	  Say Y if unsure.
1677
1678config HIGHPTE
1679	bool "Allocate 3rd-level pagetables from highmem"
1680	depends on HIGHMEM
1681	help
1682	  The VM uses one page table entry for each page of physical memory.
1683	  For systems with a lot of RAM, this can be wasteful of precious
1684	  low memory.  Setting this option will put user-space page table
1685	  entries in high memory.
1686
1687config X86_CHECK_BIOS_CORRUPTION
1688	bool "Check for low memory corruption"
1689	help
1690	  Periodically check for memory corruption in low memory, which
1691	  is suspected to be caused by BIOS.  Even when enabled in the
1692	  configuration, it is disabled at runtime.  Enable it by
1693	  setting "memory_corruption_check=1" on the kernel command
1694	  line.  By default it scans the low 64k of memory every 60
1695	  seconds; see the memory_corruption_check_size and
1696	  memory_corruption_check_period parameters in
1697	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1698
1699	  When enabled with the default parameters, this option has
1700	  almost no overhead, as it reserves a relatively small amount
1701	  of memory and scans it infrequently.  It both detects corruption
1702	  and prevents it from affecting the running system.
1703
1704	  It is, however, intended as a diagnostic tool; if repeatable
1705	  BIOS-originated corruption always affects the same memory,
1706	  you can use memmap= to prevent the kernel from using that
1707	  memory.
1708
1709config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1710	bool "Set the default setting of memory_corruption_check"
1711	depends on X86_CHECK_BIOS_CORRUPTION
1712	default y
1713	help
1714	  Set whether the default state of memory_corruption_check is
1715	  on or off.
1716
1717config MATH_EMULATION
1718	bool
1719	depends on MODIFY_LDT_SYSCALL
1720	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1721	help
1722	  Linux can emulate a math coprocessor (used for floating point
1723	  operations) if you don't have one. 486DX and Pentium processors have
1724	  a math coprocessor built in, 486SX and 386 do not, unless you added
1725	  a 487DX or 387, respectively. (The messages during boot time can
1726	  give you some hints here ["man dmesg"].) Everyone needs either a
1727	  coprocessor or this emulation.
1728
1729	  If you don't have a math coprocessor, you need to say Y here; if you
1730	  say Y here even though you have a coprocessor, the coprocessor will
1731	  be used nevertheless. (This behavior can be changed with the kernel
1732	  command line option "no387", which comes handy if your coprocessor
1733	  is broken. Try "man bootparam" or see the documentation of your boot
1734	  loader (lilo or loadlin) about how to pass options to the kernel at
1735	  boot time.) This means that it is a good idea to say Y here if you
1736	  intend to use this kernel on different machines.
1737
1738	  More information about the internals of the Linux math coprocessor
1739	  emulation can be found in <file:arch/x86/math-emu/README>.
1740
1741	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1742	  kernel, it won't hurt.
1743
1744config MTRR
1745	def_bool y
1746	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1747	help
1748	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1749	  the Memory Type Range Registers (MTRRs) may be used to control
1750	  processor access to memory ranges. This is most useful if you have
1751	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1752	  allows bus write transfers to be combined into a larger transfer
1753	  before bursting over the PCI/AGP bus. This can increase performance
1754	  of image write operations 2.5 times or more. Saying Y here creates a
1755	  /proc/mtrr file which may be used to manipulate your processor's
1756	  MTRRs. Typically the X server should use this.
1757
1758	  This code has a reasonably generic interface so that similar
1759	  control registers on other processors can be easily supported
1760	  as well:
1761
1762	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1763	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1764	  these, the ARRs are used to emulate the MTRRs.
1765	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1766	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1767	  write-combining. All of these processors are supported by this code
1768	  and it makes sense to say Y here if you have one of them.
1769
1770	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1771	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1772	  can lead to all sorts of problems, so it's good to say Y here.
1773
1774	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1775	  just add about 9 KB to your kernel.
1776
1777	  See <file:Documentation/x86/mtrr.rst> for more information.
1778
1779config MTRR_SANITIZER
1780	def_bool y
1781	prompt "MTRR cleanup support"
1782	depends on MTRR
1783	help
1784	  Convert MTRR layout from continuous to discrete, so X drivers can
1785	  add writeback entries.
1786
1787	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1788	  The largest mtrr entry size for a continuous block can be set with
1789	  mtrr_chunk_size.
1790
1791	  If unsure, say Y.
1792
1793config MTRR_SANITIZER_ENABLE_DEFAULT
1794	int "MTRR cleanup enable value (0-1)"
1795	range 0 1
1796	default "0"
1797	depends on MTRR_SANITIZER
1798	help
1799	  Enable mtrr cleanup default value
1800
1801config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1802	int "MTRR cleanup spare reg num (0-7)"
1803	range 0 7
1804	default "1"
1805	depends on MTRR_SANITIZER
1806	help
1807	  mtrr cleanup spare entries default, it can be changed via
1808	  mtrr_spare_reg_nr=N on the kernel command line.
1809
1810config X86_PAT
1811	def_bool y
1812	prompt "x86 PAT support" if EXPERT
1813	depends on MTRR
1814	help
1815	  Use PAT attributes to setup page level cache control.
1816
1817	  PATs are the modern equivalents of MTRRs and are much more
1818	  flexible than MTRRs.
1819
1820	  Say N here if you see bootup problems (boot crash, boot hang,
1821	  spontaneous reboots) or a non-working video driver.
1822
1823	  If unsure, say Y.
1824
1825config ARCH_USES_PG_UNCACHED
1826	def_bool y
1827	depends on X86_PAT
1828
1829config ARCH_RANDOM
1830	def_bool y
1831	prompt "x86 architectural random number generator" if EXPERT
1832	help
1833	  Enable the x86 architectural RDRAND instruction
1834	  (Intel Bull Mountain technology) to generate random numbers.
1835	  If supported, this is a high bandwidth, cryptographically
1836	  secure hardware random number generator.
1837
1838config X86_SMAP
1839	def_bool y
1840	prompt "Supervisor Mode Access Prevention" if EXPERT
1841	help
1842	  Supervisor Mode Access Prevention (SMAP) is a security
1843	  feature in newer Intel processors.  There is a small
1844	  performance cost if this enabled and turned on; there is
1845	  also a small increase in the kernel size if this is enabled.
1846
1847	  If unsure, say Y.
1848
1849config X86_UMIP
1850	def_bool y
1851	prompt "User Mode Instruction Prevention" if EXPERT
1852	help
1853	  User Mode Instruction Prevention (UMIP) is a security feature in
1854	  some x86 processors. If enabled, a general protection fault is
1855	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1856	  executed in user mode. These instructions unnecessarily expose
1857	  information about the hardware state.
1858
1859	  The vast majority of applications do not use these instructions.
1860	  For the very few that do, software emulation is provided in
1861	  specific cases in protected and virtual-8086 modes. Emulated
1862	  results are dummy.
1863
1864config CC_HAS_IBT
1865	# GCC >= 9 and binutils >= 2.29
1866	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1867	# Clang/LLVM >= 14
1868	# fentry check to work around https://reviews.llvm.org/D111108
1869	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1870		  (CC_IS_CLANG && $(success,echo "void a(void) {}" | $(CC) -Werror $(CLANG_FLAGS) -fcf-protection=branch -mfentry -pg -x c - -c -o /dev/null))) && \
1871		  $(as-instr,endbr64)
1872
1873config X86_KERNEL_IBT
1874	prompt "Indirect Branch Tracking"
1875	bool
1876	depends on X86_64 && CC_HAS_IBT
1877	help
1878	  Build the kernel with support for Indirect Branch Tracking, a
1879	  hardware support course-grain forward-edge Control Flow Integrity
1880	  protection. It enforces that all indirect calls must land on
1881	  an ENDBR instruction, as such, the compiler will instrument the
1882	  code with them to make this happen.
1883
1884config X86_INTEL_MEMORY_PROTECTION_KEYS
1885	prompt "Memory Protection Keys"
1886	def_bool y
1887	# Note: only available in 64-bit mode
1888	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1889	select ARCH_USES_HIGH_VMA_FLAGS
1890	select ARCH_HAS_PKEYS
1891	help
1892	  Memory Protection Keys provides a mechanism for enforcing
1893	  page-based protections, but without requiring modification of the
1894	  page tables when an application changes protection domains.
1895
1896	  For details, see Documentation/core-api/protection-keys.rst
1897
1898	  If unsure, say y.
1899
1900choice
1901	prompt "TSX enable mode"
1902	depends on CPU_SUP_INTEL
1903	default X86_INTEL_TSX_MODE_OFF
1904	help
1905	  Intel's TSX (Transactional Synchronization Extensions) feature
1906	  allows to optimize locking protocols through lock elision which
1907	  can lead to a noticeable performance boost.
1908
1909	  On the other hand it has been shown that TSX can be exploited
1910	  to form side channel attacks (e.g. TAA) and chances are there
1911	  will be more of those attacks discovered in the future.
1912
1913	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1914	  might override this decision by tsx=on the command line parameter.
1915	  Even with TSX enabled, the kernel will attempt to enable the best
1916	  possible TAA mitigation setting depending on the microcode available
1917	  for the particular machine.
1918
1919	  This option allows to set the default tsx mode between tsx=on, =off
1920	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1921	  details.
1922
1923	  Say off if not sure, auto if TSX is in use but it should be used on safe
1924	  platforms or on if TSX is in use and the security aspect of tsx is not
1925	  relevant.
1926
1927config X86_INTEL_TSX_MODE_OFF
1928	bool "off"
1929	help
1930	  TSX is disabled if possible - equals to tsx=off command line parameter.
1931
1932config X86_INTEL_TSX_MODE_ON
1933	bool "on"
1934	help
1935	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1936	  line parameter.
1937
1938config X86_INTEL_TSX_MODE_AUTO
1939	bool "auto"
1940	help
1941	  TSX is enabled on TSX capable HW that is believed to be safe against
1942	  side channel attacks- equals the tsx=auto command line parameter.
1943endchoice
1944
1945config X86_SGX
1946	bool "Software Guard eXtensions (SGX)"
1947	depends on X86_64 && CPU_SUP_INTEL
1948	depends on CRYPTO=y
1949	depends on CRYPTO_SHA256=y
1950	select SRCU
1951	select MMU_NOTIFIER
1952	select NUMA_KEEP_MEMINFO if NUMA
1953	select XARRAY_MULTI
1954	help
1955	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1956	  that can be used by applications to set aside private regions of code
1957	  and data, referred to as enclaves. An enclave's private memory can
1958	  only be accessed by code running within the enclave. Accesses from
1959	  outside the enclave, including other enclaves, are disallowed by
1960	  hardware.
1961
1962	  If unsure, say N.
1963
1964config EFI
1965	bool "EFI runtime service support"
1966	depends on ACPI
1967	select UCS2_STRING
1968	select EFI_RUNTIME_WRAPPERS
1969	select ARCH_USE_MEMREMAP_PROT
1970	help
1971	  This enables the kernel to use EFI runtime services that are
1972	  available (such as the EFI variable services).
1973
1974	  This option is only useful on systems that have EFI firmware.
1975	  In addition, you should use the latest ELILO loader available
1976	  at <http://elilo.sourceforge.net> in order to take advantage
1977	  of EFI runtime services. However, even with this option, the
1978	  resultant kernel should continue to boot on existing non-EFI
1979	  platforms.
1980
1981config EFI_STUB
1982	bool "EFI stub support"
1983	depends on EFI
1984	depends on $(cc-option,-mabi=ms) || X86_32
1985	select RELOCATABLE
1986	help
1987	  This kernel feature allows a bzImage to be loaded directly
1988	  by EFI firmware without the use of a bootloader.
1989
1990	  See Documentation/admin-guide/efi-stub.rst for more information.
1991
1992config EFI_MIXED
1993	bool "EFI mixed-mode support"
1994	depends on EFI_STUB && X86_64
1995	help
1996	   Enabling this feature allows a 64-bit kernel to be booted
1997	   on a 32-bit firmware, provided that your CPU supports 64-bit
1998	   mode.
1999
2000	   Note that it is not possible to boot a mixed-mode enabled
2001	   kernel via the EFI boot stub - a bootloader that supports
2002	   the EFI handover protocol must be used.
2003
2004	   If unsure, say N.
2005
2006source "kernel/Kconfig.hz"
2007
2008config KEXEC
2009	bool "kexec system call"
2010	select KEXEC_CORE
2011	help
2012	  kexec is a system call that implements the ability to shutdown your
2013	  current kernel, and to start another kernel.  It is like a reboot
2014	  but it is independent of the system firmware.   And like a reboot
2015	  you can start any kernel with it, not just Linux.
2016
2017	  The name comes from the similarity to the exec system call.
2018
2019	  It is an ongoing process to be certain the hardware in a machine
2020	  is properly shutdown, so do not be surprised if this code does not
2021	  initially work for you.  As of this writing the exact hardware
2022	  interface is strongly in flux, so no good recommendation can be
2023	  made.
2024
2025config KEXEC_FILE
2026	bool "kexec file based system call"
2027	select KEXEC_CORE
2028	select BUILD_BIN2C
2029	depends on X86_64
2030	depends on CRYPTO=y
2031	depends on CRYPTO_SHA256=y
2032	help
2033	  This is new version of kexec system call. This system call is
2034	  file based and takes file descriptors as system call argument
2035	  for kernel and initramfs as opposed to list of segments as
2036	  accepted by previous system call.
2037
2038config ARCH_HAS_KEXEC_PURGATORY
2039	def_bool KEXEC_FILE
2040
2041config KEXEC_SIG
2042	bool "Verify kernel signature during kexec_file_load() syscall"
2043	depends on KEXEC_FILE
2044	help
2045
2046	  This option makes the kexec_file_load() syscall check for a valid
2047	  signature of the kernel image.  The image can still be loaded without
2048	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2049	  there's a signature that we can check, then it must be valid.
2050
2051	  In addition to this option, you need to enable signature
2052	  verification for the corresponding kernel image type being
2053	  loaded in order for this to work.
2054
2055config KEXEC_SIG_FORCE
2056	bool "Require a valid signature in kexec_file_load() syscall"
2057	depends on KEXEC_SIG
2058	help
2059	  This option makes kernel signature verification mandatory for
2060	  the kexec_file_load() syscall.
2061
2062config KEXEC_BZIMAGE_VERIFY_SIG
2063	bool "Enable bzImage signature verification support"
2064	depends on KEXEC_SIG
2065	depends on SIGNED_PE_FILE_VERIFICATION
2066	select SYSTEM_TRUSTED_KEYRING
2067	help
2068	  Enable bzImage signature verification support.
2069
2070config CRASH_DUMP
2071	bool "kernel crash dumps"
2072	depends on X86_64 || (X86_32 && HIGHMEM)
2073	help
2074	  Generate crash dump after being started by kexec.
2075	  This should be normally only set in special crash dump kernels
2076	  which are loaded in the main kernel with kexec-tools into
2077	  a specially reserved region and then later executed after
2078	  a crash by kdump/kexec. The crash dump kernel must be compiled
2079	  to a memory address not used by the main kernel or BIOS using
2080	  PHYSICAL_START, or it must be built as a relocatable image
2081	  (CONFIG_RELOCATABLE=y).
2082	  For more details see Documentation/admin-guide/kdump/kdump.rst
2083
2084config KEXEC_JUMP
2085	bool "kexec jump"
2086	depends on KEXEC && HIBERNATION
2087	help
2088	  Jump between original kernel and kexeced kernel and invoke
2089	  code in physical address mode via KEXEC
2090
2091config PHYSICAL_START
2092	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2093	default "0x1000000"
2094	help
2095	  This gives the physical address where the kernel is loaded.
2096
2097	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2098	  bzImage will decompress itself to above physical address and
2099	  run from there. Otherwise, bzImage will run from the address where
2100	  it has been loaded by the boot loader and will ignore above physical
2101	  address.
2102
2103	  In normal kdump cases one does not have to set/change this option
2104	  as now bzImage can be compiled as a completely relocatable image
2105	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2106	  address. This option is mainly useful for the folks who don't want
2107	  to use a bzImage for capturing the crash dump and want to use a
2108	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2109	  to be specifically compiled to run from a specific memory area
2110	  (normally a reserved region) and this option comes handy.
2111
2112	  So if you are using bzImage for capturing the crash dump,
2113	  leave the value here unchanged to 0x1000000 and set
2114	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2115	  for capturing the crash dump change this value to start of
2116	  the reserved region.  In other words, it can be set based on
2117	  the "X" value as specified in the "crashkernel=YM@XM"
2118	  command line boot parameter passed to the panic-ed
2119	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2120	  for more details about crash dumps.
2121
2122	  Usage of bzImage for capturing the crash dump is recommended as
2123	  one does not have to build two kernels. Same kernel can be used
2124	  as production kernel and capture kernel. Above option should have
2125	  gone away after relocatable bzImage support is introduced. But it
2126	  is present because there are users out there who continue to use
2127	  vmlinux for dump capture. This option should go away down the
2128	  line.
2129
2130	  Don't change this unless you know what you are doing.
2131
2132config RELOCATABLE
2133	bool "Build a relocatable kernel"
2134	default y
2135	help
2136	  This builds a kernel image that retains relocation information
2137	  so it can be loaded someplace besides the default 1MB.
2138	  The relocations tend to make the kernel binary about 10% larger,
2139	  but are discarded at runtime.
2140
2141	  One use is for the kexec on panic case where the recovery kernel
2142	  must live at a different physical address than the primary
2143	  kernel.
2144
2145	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2146	  it has been loaded at and the compile time physical address
2147	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2148
2149config RANDOMIZE_BASE
2150	bool "Randomize the address of the kernel image (KASLR)"
2151	depends on RELOCATABLE
2152	default y
2153	help
2154	  In support of Kernel Address Space Layout Randomization (KASLR),
2155	  this randomizes the physical address at which the kernel image
2156	  is decompressed and the virtual address where the kernel
2157	  image is mapped, as a security feature that deters exploit
2158	  attempts relying on knowledge of the location of kernel
2159	  code internals.
2160
2161	  On 64-bit, the kernel physical and virtual addresses are
2162	  randomized separately. The physical address will be anywhere
2163	  between 16MB and the top of physical memory (up to 64TB). The
2164	  virtual address will be randomized from 16MB up to 1GB (9 bits
2165	  of entropy). Note that this also reduces the memory space
2166	  available to kernel modules from 1.5GB to 1GB.
2167
2168	  On 32-bit, the kernel physical and virtual addresses are
2169	  randomized together. They will be randomized from 16MB up to
2170	  512MB (8 bits of entropy).
2171
2172	  Entropy is generated using the RDRAND instruction if it is
2173	  supported. If RDTSC is supported, its value is mixed into
2174	  the entropy pool as well. If neither RDRAND nor RDTSC are
2175	  supported, then entropy is read from the i8254 timer. The
2176	  usable entropy is limited by the kernel being built using
2177	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2178	  minimum of 2MB. As a result, only 10 bits of entropy are
2179	  theoretically possible, but the implementations are further
2180	  limited due to memory layouts.
2181
2182	  If unsure, say Y.
2183
2184# Relocation on x86 needs some additional build support
2185config X86_NEED_RELOCS
2186	def_bool y
2187	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2188
2189config PHYSICAL_ALIGN
2190	hex "Alignment value to which kernel should be aligned"
2191	default "0x200000"
2192	range 0x2000 0x1000000 if X86_32
2193	range 0x200000 0x1000000 if X86_64
2194	help
2195	  This value puts the alignment restrictions on physical address
2196	  where kernel is loaded and run from. Kernel is compiled for an
2197	  address which meets above alignment restriction.
2198
2199	  If bootloader loads the kernel at a non-aligned address and
2200	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2201	  address aligned to above value and run from there.
2202
2203	  If bootloader loads the kernel at a non-aligned address and
2204	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2205	  load address and decompress itself to the address it has been
2206	  compiled for and run from there. The address for which kernel is
2207	  compiled already meets above alignment restrictions. Hence the
2208	  end result is that kernel runs from a physical address meeting
2209	  above alignment restrictions.
2210
2211	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2212	  this value must be a multiple of 0x200000.
2213
2214	  Don't change this unless you know what you are doing.
2215
2216config DYNAMIC_MEMORY_LAYOUT
2217	bool
2218	help
2219	  This option makes base addresses of vmalloc and vmemmap as well as
2220	  __PAGE_OFFSET movable during boot.
2221
2222config RANDOMIZE_MEMORY
2223	bool "Randomize the kernel memory sections"
2224	depends on X86_64
2225	depends on RANDOMIZE_BASE
2226	select DYNAMIC_MEMORY_LAYOUT
2227	default RANDOMIZE_BASE
2228	help
2229	   Randomizes the base virtual address of kernel memory sections
2230	   (physical memory mapping, vmalloc & vmemmap). This security feature
2231	   makes exploits relying on predictable memory locations less reliable.
2232
2233	   The order of allocations remains unchanged. Entropy is generated in
2234	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2235	   configuration have in average 30,000 different possible virtual
2236	   addresses for each memory section.
2237
2238	   If unsure, say Y.
2239
2240config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2241	hex "Physical memory mapping padding" if EXPERT
2242	depends on RANDOMIZE_MEMORY
2243	default "0xa" if MEMORY_HOTPLUG
2244	default "0x0"
2245	range 0x1 0x40 if MEMORY_HOTPLUG
2246	range 0x0 0x40
2247	help
2248	   Define the padding in terabytes added to the existing physical
2249	   memory size during kernel memory randomization. It is useful
2250	   for memory hotplug support but reduces the entropy available for
2251	   address randomization.
2252
2253	   If unsure, leave at the default value.
2254
2255config HOTPLUG_CPU
2256	def_bool y
2257	depends on SMP
2258
2259config BOOTPARAM_HOTPLUG_CPU0
2260	bool "Set default setting of cpu0_hotpluggable"
2261	depends on HOTPLUG_CPU
2262	help
2263	  Set whether default state of cpu0_hotpluggable is on or off.
2264
2265	  Say Y here to enable CPU0 hotplug by default. If this switch
2266	  is turned on, there is no need to give cpu0_hotplug kernel
2267	  parameter and the CPU0 hotplug feature is enabled by default.
2268
2269	  Please note: there are two known CPU0 dependencies if you want
2270	  to enable the CPU0 hotplug feature either by this switch or by
2271	  cpu0_hotplug kernel parameter.
2272
2273	  First, resume from hibernate or suspend always starts from CPU0.
2274	  So hibernate and suspend are prevented if CPU0 is offline.
2275
2276	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2277	  offline if any interrupt can not migrate out of CPU0. There may
2278	  be other CPU0 dependencies.
2279
2280	  Please make sure the dependencies are under your control before
2281	  you enable this feature.
2282
2283	  Say N if you don't want to enable CPU0 hotplug feature by default.
2284	  You still can enable the CPU0 hotplug feature at boot by kernel
2285	  parameter cpu0_hotplug.
2286
2287config DEBUG_HOTPLUG_CPU0
2288	def_bool n
2289	prompt "Debug CPU0 hotplug"
2290	depends on HOTPLUG_CPU
2291	help
2292	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2293	  soon as possible and boots up userspace with CPU0 offlined. User
2294	  can online CPU0 back after boot time.
2295
2296	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2297	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2298	  compilation or giving cpu0_hotplug kernel parameter at boot.
2299
2300	  If unsure, say N.
2301
2302config COMPAT_VDSO
2303	def_bool n
2304	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2305	depends on COMPAT_32
2306	help
2307	  Certain buggy versions of glibc will crash if they are
2308	  presented with a 32-bit vDSO that is not mapped at the address
2309	  indicated in its segment table.
2310
2311	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2312	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2313	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2314	  the only released version with the bug, but OpenSUSE 9
2315	  contains a buggy "glibc 2.3.2".
2316
2317	  The symptom of the bug is that everything crashes on startup, saying:
2318	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2319
2320	  Saying Y here changes the default value of the vdso32 boot
2321	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2322	  This works around the glibc bug but hurts performance.
2323
2324	  If unsure, say N: if you are compiling your own kernel, you
2325	  are unlikely to be using a buggy version of glibc.
2326
2327choice
2328	prompt "vsyscall table for legacy applications"
2329	depends on X86_64
2330	default LEGACY_VSYSCALL_XONLY
2331	help
2332	  Legacy user code that does not know how to find the vDSO expects
2333	  to be able to issue three syscalls by calling fixed addresses in
2334	  kernel space. Since this location is not randomized with ASLR,
2335	  it can be used to assist security vulnerability exploitation.
2336
2337	  This setting can be changed at boot time via the kernel command
2338	  line parameter vsyscall=[emulate|xonly|none].
2339
2340	  On a system with recent enough glibc (2.14 or newer) and no
2341	  static binaries, you can say None without a performance penalty
2342	  to improve security.
2343
2344	  If unsure, select "Emulate execution only".
2345
2346	config LEGACY_VSYSCALL_EMULATE
2347		bool "Full emulation"
2348		help
2349		  The kernel traps and emulates calls into the fixed vsyscall
2350		  address mapping. This makes the mapping non-executable, but
2351		  it still contains readable known contents, which could be
2352		  used in certain rare security vulnerability exploits. This
2353		  configuration is recommended when using legacy userspace
2354		  that still uses vsyscalls along with legacy binary
2355		  instrumentation tools that require code to be readable.
2356
2357		  An example of this type of legacy userspace is running
2358		  Pin on an old binary that still uses vsyscalls.
2359
2360	config LEGACY_VSYSCALL_XONLY
2361		bool "Emulate execution only"
2362		help
2363		  The kernel traps and emulates calls into the fixed vsyscall
2364		  address mapping and does not allow reads.  This
2365		  configuration is recommended when userspace might use the
2366		  legacy vsyscall area but support for legacy binary
2367		  instrumentation of legacy code is not needed.  It mitigates
2368		  certain uses of the vsyscall area as an ASLR-bypassing
2369		  buffer.
2370
2371	config LEGACY_VSYSCALL_NONE
2372		bool "None"
2373		help
2374		  There will be no vsyscall mapping at all. This will
2375		  eliminate any risk of ASLR bypass due to the vsyscall
2376		  fixed address mapping. Attempts to use the vsyscalls
2377		  will be reported to dmesg, so that either old or
2378		  malicious userspace programs can be identified.
2379
2380endchoice
2381
2382config CMDLINE_BOOL
2383	bool "Built-in kernel command line"
2384	help
2385	  Allow for specifying boot arguments to the kernel at
2386	  build time.  On some systems (e.g. embedded ones), it is
2387	  necessary or convenient to provide some or all of the
2388	  kernel boot arguments with the kernel itself (that is,
2389	  to not rely on the boot loader to provide them.)
2390
2391	  To compile command line arguments into the kernel,
2392	  set this option to 'Y', then fill in the
2393	  boot arguments in CONFIG_CMDLINE.
2394
2395	  Systems with fully functional boot loaders (i.e. non-embedded)
2396	  should leave this option set to 'N'.
2397
2398config CMDLINE
2399	string "Built-in kernel command string"
2400	depends on CMDLINE_BOOL
2401	default ""
2402	help
2403	  Enter arguments here that should be compiled into the kernel
2404	  image and used at boot time.  If the boot loader provides a
2405	  command line at boot time, it is appended to this string to
2406	  form the full kernel command line, when the system boots.
2407
2408	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2409	  change this behavior.
2410
2411	  In most cases, the command line (whether built-in or provided
2412	  by the boot loader) should specify the device for the root
2413	  file system.
2414
2415config CMDLINE_OVERRIDE
2416	bool "Built-in command line overrides boot loader arguments"
2417	depends on CMDLINE_BOOL && CMDLINE != ""
2418	help
2419	  Set this option to 'Y' to have the kernel ignore the boot loader
2420	  command line, and use ONLY the built-in command line.
2421
2422	  This is used to work around broken boot loaders.  This should
2423	  be set to 'N' under normal conditions.
2424
2425config MODIFY_LDT_SYSCALL
2426	bool "Enable the LDT (local descriptor table)" if EXPERT
2427	default y
2428	help
2429	  Linux can allow user programs to install a per-process x86
2430	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2431	  call.  This is required to run 16-bit or segmented code such as
2432	  DOSEMU or some Wine programs.  It is also used by some very old
2433	  threading libraries.
2434
2435	  Enabling this feature adds a small amount of overhead to
2436	  context switches and increases the low-level kernel attack
2437	  surface.  Disabling it removes the modify_ldt(2) system call.
2438
2439	  Saying 'N' here may make sense for embedded or server kernels.
2440
2441config STRICT_SIGALTSTACK_SIZE
2442	bool "Enforce strict size checking for sigaltstack"
2443	depends on DYNAMIC_SIGFRAME
2444	help
2445	  For historical reasons MINSIGSTKSZ is a constant which became
2446	  already too small with AVX512 support. Add a mechanism to
2447	  enforce strict checking of the sigaltstack size against the
2448	  real size of the FPU frame. This option enables the check
2449	  by default. It can also be controlled via the kernel command
2450	  line option 'strict_sas_size' independent of this config
2451	  switch. Enabling it might break existing applications which
2452	  allocate a too small sigaltstack but 'work' because they
2453	  never get a signal delivered.
2454
2455	  Say 'N' unless you want to really enforce this check.
2456
2457source "kernel/livepatch/Kconfig"
2458
2459endmenu
2460
2461config ARCH_HAS_ADD_PAGES
2462	def_bool y
2463	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2464
2465config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2466	def_bool y
2467
2468menu "Power management and ACPI options"
2469
2470config ARCH_HIBERNATION_HEADER
2471	def_bool y
2472	depends on HIBERNATION
2473
2474source "kernel/power/Kconfig"
2475
2476source "drivers/acpi/Kconfig"
2477
2478config X86_APM_BOOT
2479	def_bool y
2480	depends on APM
2481
2482menuconfig APM
2483	tristate "APM (Advanced Power Management) BIOS support"
2484	depends on X86_32 && PM_SLEEP
2485	help
2486	  APM is a BIOS specification for saving power using several different
2487	  techniques. This is mostly useful for battery powered laptops with
2488	  APM compliant BIOSes. If you say Y here, the system time will be
2489	  reset after a RESUME operation, the /proc/apm device will provide
2490	  battery status information, and user-space programs will receive
2491	  notification of APM "events" (e.g. battery status change).
2492
2493	  If you select "Y" here, you can disable actual use of the APM
2494	  BIOS by passing the "apm=off" option to the kernel at boot time.
2495
2496	  Note that the APM support is almost completely disabled for
2497	  machines with more than one CPU.
2498
2499	  In order to use APM, you will need supporting software. For location
2500	  and more information, read <file:Documentation/power/apm-acpi.rst>
2501	  and the Battery Powered Linux mini-HOWTO, available from
2502	  <http://www.tldp.org/docs.html#howto>.
2503
2504	  This driver does not spin down disk drives (see the hdparm(8)
2505	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2506	  VESA-compliant "green" monitors.
2507
2508	  This driver does not support the TI 4000M TravelMate and the ACER
2509	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2510	  desktop machines also don't have compliant BIOSes, and this driver
2511	  may cause those machines to panic during the boot phase.
2512
2513	  Generally, if you don't have a battery in your machine, there isn't
2514	  much point in using this driver and you should say N. If you get
2515	  random kernel OOPSes or reboots that don't seem to be related to
2516	  anything, try disabling/enabling this option (or disabling/enabling
2517	  APM in your BIOS).
2518
2519	  Some other things you should try when experiencing seemingly random,
2520	  "weird" problems:
2521
2522	  1) make sure that you have enough swap space and that it is
2523	  enabled.
2524	  2) pass the "no-hlt" option to the kernel
2525	  3) switch on floating point emulation in the kernel and pass
2526	  the "no387" option to the kernel
2527	  4) pass the "floppy=nodma" option to the kernel
2528	  5) pass the "mem=4M" option to the kernel (thereby disabling
2529	  all but the first 4 MB of RAM)
2530	  6) make sure that the CPU is not over clocked.
2531	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2532	  8) disable the cache from your BIOS settings
2533	  9) install a fan for the video card or exchange video RAM
2534	  10) install a better fan for the CPU
2535	  11) exchange RAM chips
2536	  12) exchange the motherboard.
2537
2538	  To compile this driver as a module, choose M here: the
2539	  module will be called apm.
2540
2541if APM
2542
2543config APM_IGNORE_USER_SUSPEND
2544	bool "Ignore USER SUSPEND"
2545	help
2546	  This option will ignore USER SUSPEND requests. On machines with a
2547	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2548	  series notebooks, it is necessary to say Y because of a BIOS bug.
2549
2550config APM_DO_ENABLE
2551	bool "Enable PM at boot time"
2552	help
2553	  Enable APM features at boot time. From page 36 of the APM BIOS
2554	  specification: "When disabled, the APM BIOS does not automatically
2555	  power manage devices, enter the Standby State, enter the Suspend
2556	  State, or take power saving steps in response to CPU Idle calls."
2557	  This driver will make CPU Idle calls when Linux is idle (unless this
2558	  feature is turned off -- see "Do CPU IDLE calls", below). This
2559	  should always save battery power, but more complicated APM features
2560	  will be dependent on your BIOS implementation. You may need to turn
2561	  this option off if your computer hangs at boot time when using APM
2562	  support, or if it beeps continuously instead of suspending. Turn
2563	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2564	  T400CDT. This is off by default since most machines do fine without
2565	  this feature.
2566
2567config APM_CPU_IDLE
2568	depends on CPU_IDLE
2569	bool "Make CPU Idle calls when idle"
2570	help
2571	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2572	  On some machines, this can activate improved power savings, such as
2573	  a slowed CPU clock rate, when the machine is idle. These idle calls
2574	  are made after the idle loop has run for some length of time (e.g.,
2575	  333 mS). On some machines, this will cause a hang at boot time or
2576	  whenever the CPU becomes idle. (On machines with more than one CPU,
2577	  this option does nothing.)
2578
2579config APM_DISPLAY_BLANK
2580	bool "Enable console blanking using APM"
2581	help
2582	  Enable console blanking using the APM. Some laptops can use this to
2583	  turn off the LCD backlight when the screen blanker of the Linux
2584	  virtual console blanks the screen. Note that this is only used by
2585	  the virtual console screen blanker, and won't turn off the backlight
2586	  when using the X Window system. This also doesn't have anything to
2587	  do with your VESA-compliant power-saving monitor. Further, this
2588	  option doesn't work for all laptops -- it might not turn off your
2589	  backlight at all, or it might print a lot of errors to the console,
2590	  especially if you are using gpm.
2591
2592config APM_ALLOW_INTS
2593	bool "Allow interrupts during APM BIOS calls"
2594	help
2595	  Normally we disable external interrupts while we are making calls to
2596	  the APM BIOS as a measure to lessen the effects of a badly behaving
2597	  BIOS implementation.  The BIOS should reenable interrupts if it
2598	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2599	  many of the newer IBM Thinkpads.  If you experience hangs when you
2600	  suspend, try setting this to Y.  Otherwise, say N.
2601
2602endif # APM
2603
2604source "drivers/cpufreq/Kconfig"
2605
2606source "drivers/cpuidle/Kconfig"
2607
2608source "drivers/idle/Kconfig"
2609
2610endmenu
2611
2612
2613menu "Bus options (PCI etc.)"
2614
2615choice
2616	prompt "PCI access mode"
2617	depends on X86_32 && PCI
2618	default PCI_GOANY
2619	help
2620	  On PCI systems, the BIOS can be used to detect the PCI devices and
2621	  determine their configuration. However, some old PCI motherboards
2622	  have BIOS bugs and may crash if this is done. Also, some embedded
2623	  PCI-based systems don't have any BIOS at all. Linux can also try to
2624	  detect the PCI hardware directly without using the BIOS.
2625
2626	  With this option, you can specify how Linux should detect the
2627	  PCI devices. If you choose "BIOS", the BIOS will be used,
2628	  if you choose "Direct", the BIOS won't be used, and if you
2629	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2630	  If you choose "Any", the kernel will try MMCONFIG, then the
2631	  direct access method and falls back to the BIOS if that doesn't
2632	  work. If unsure, go with the default, which is "Any".
2633
2634config PCI_GOBIOS
2635	bool "BIOS"
2636
2637config PCI_GOMMCONFIG
2638	bool "MMConfig"
2639
2640config PCI_GODIRECT
2641	bool "Direct"
2642
2643config PCI_GOOLPC
2644	bool "OLPC XO-1"
2645	depends on OLPC
2646
2647config PCI_GOANY
2648	bool "Any"
2649
2650endchoice
2651
2652config PCI_BIOS
2653	def_bool y
2654	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2655
2656# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2657config PCI_DIRECT
2658	def_bool y
2659	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2660
2661config PCI_MMCONFIG
2662	bool "Support mmconfig PCI config space access" if X86_64
2663	default y
2664	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2665	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2666
2667config PCI_OLPC
2668	def_bool y
2669	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2670
2671config PCI_XEN
2672	def_bool y
2673	depends on PCI && XEN
2674
2675config MMCONF_FAM10H
2676	def_bool y
2677	depends on X86_64 && PCI_MMCONFIG && ACPI
2678
2679config PCI_CNB20LE_QUIRK
2680	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2681	depends on PCI
2682	help
2683	  Read the PCI windows out of the CNB20LE host bridge. This allows
2684	  PCI hotplug to work on systems with the CNB20LE chipset which do
2685	  not have ACPI.
2686
2687	  There's no public spec for this chipset, and this functionality
2688	  is known to be incomplete.
2689
2690	  You should say N unless you know you need this.
2691
2692config ISA_BUS
2693	bool "ISA bus support on modern systems" if EXPERT
2694	help
2695	  Expose ISA bus device drivers and options available for selection and
2696	  configuration. Enable this option if your target machine has an ISA
2697	  bus. ISA is an older system, displaced by PCI and newer bus
2698	  architectures -- if your target machine is modern, it probably does
2699	  not have an ISA bus.
2700
2701	  If unsure, say N.
2702
2703# x86_64 have no ISA slots, but can have ISA-style DMA.
2704config ISA_DMA_API
2705	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2706	default y
2707	help
2708	  Enables ISA-style DMA support for devices requiring such controllers.
2709	  If unsure, say Y.
2710
2711if X86_32
2712
2713config ISA
2714	bool "ISA support"
2715	help
2716	  Find out whether you have ISA slots on your motherboard.  ISA is the
2717	  name of a bus system, i.e. the way the CPU talks to the other stuff
2718	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2719	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2720	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2721
2722config SCx200
2723	tristate "NatSemi SCx200 support"
2724	help
2725	  This provides basic support for National Semiconductor's
2726	  (now AMD's) Geode processors.  The driver probes for the
2727	  PCI-IDs of several on-chip devices, so its a good dependency
2728	  for other scx200_* drivers.
2729
2730	  If compiled as a module, the driver is named scx200.
2731
2732config SCx200HR_TIMER
2733	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2734	depends on SCx200
2735	default y
2736	help
2737	  This driver provides a clocksource built upon the on-chip
2738	  27MHz high-resolution timer.  Its also a workaround for
2739	  NSC Geode SC-1100's buggy TSC, which loses time when the
2740	  processor goes idle (as is done by the scheduler).  The
2741	  other workaround is idle=poll boot option.
2742
2743config OLPC
2744	bool "One Laptop Per Child support"
2745	depends on !X86_PAE
2746	select GPIOLIB
2747	select OF
2748	select OF_PROMTREE
2749	select IRQ_DOMAIN
2750	select OLPC_EC
2751	help
2752	  Add support for detecting the unique features of the OLPC
2753	  XO hardware.
2754
2755config OLPC_XO1_PM
2756	bool "OLPC XO-1 Power Management"
2757	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2758	help
2759	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2760
2761config OLPC_XO1_RTC
2762	bool "OLPC XO-1 Real Time Clock"
2763	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2764	help
2765	  Add support for the XO-1 real time clock, which can be used as a
2766	  programmable wakeup source.
2767
2768config OLPC_XO1_SCI
2769	bool "OLPC XO-1 SCI extras"
2770	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2771	depends on INPUT=y
2772	select POWER_SUPPLY
2773	help
2774	  Add support for SCI-based features of the OLPC XO-1 laptop:
2775	   - EC-driven system wakeups
2776	   - Power button
2777	   - Ebook switch
2778	   - Lid switch
2779	   - AC adapter status updates
2780	   - Battery status updates
2781
2782config OLPC_XO15_SCI
2783	bool "OLPC XO-1.5 SCI extras"
2784	depends on OLPC && ACPI
2785	select POWER_SUPPLY
2786	help
2787	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2788	   - EC-driven system wakeups
2789	   - AC adapter status updates
2790	   - Battery status updates
2791
2792config ALIX
2793	bool "PCEngines ALIX System Support (LED setup)"
2794	select GPIOLIB
2795	help
2796	  This option enables system support for the PCEngines ALIX.
2797	  At present this just sets up LEDs for GPIO control on
2798	  ALIX2/3/6 boards.  However, other system specific setup should
2799	  get added here.
2800
2801	  Note: You must still enable the drivers for GPIO and LED support
2802	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2803
2804	  Note: You have to set alix.force=1 for boards with Award BIOS.
2805
2806config NET5501
2807	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2808	select GPIOLIB
2809	help
2810	  This option enables system support for the Soekris Engineering net5501.
2811
2812config GEOS
2813	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2814	select GPIOLIB
2815	depends on DMI
2816	help
2817	  This option enables system support for the Traverse Technologies GEOS.
2818
2819config TS5500
2820	bool "Technologic Systems TS-5500 platform support"
2821	depends on MELAN
2822	select CHECK_SIGNATURE
2823	select NEW_LEDS
2824	select LEDS_CLASS
2825	help
2826	  This option enables system support for the Technologic Systems TS-5500.
2827
2828endif # X86_32
2829
2830config AMD_NB
2831	def_bool y
2832	depends on CPU_SUP_AMD && PCI
2833
2834endmenu
2835
2836
2837menu "Binary Emulations"
2838
2839config IA32_EMULATION
2840	bool "IA32 Emulation"
2841	depends on X86_64
2842	select ARCH_WANT_OLD_COMPAT_IPC
2843	select BINFMT_ELF
2844	select COMPAT_OLD_SIGACTION
2845	help
2846	  Include code to run legacy 32-bit programs under a
2847	  64-bit kernel. You should likely turn this on, unless you're
2848	  100% sure that you don't have any 32-bit programs left.
2849
2850config IA32_AOUT
2851	tristate "IA32 a.out support"
2852	depends on IA32_EMULATION
2853	depends on BROKEN
2854	help
2855	  Support old a.out binaries in the 32bit emulation.
2856
2857config X86_X32
2858	bool "x32 ABI for 64-bit mode"
2859	depends on X86_64
2860	help
2861	  Include code to run binaries for the x32 native 32-bit ABI
2862	  for 64-bit processors.  An x32 process gets access to the
2863	  full 64-bit register file and wide data path while leaving
2864	  pointers at 32 bits for smaller memory footprint.
2865
2866	  You will need a recent binutils (2.22 or later) with
2867	  elf32_x86_64 support enabled to compile a kernel with this
2868	  option set.
2869
2870config COMPAT_32
2871	def_bool y
2872	depends on IA32_EMULATION || X86_32
2873	select HAVE_UID16
2874	select OLD_SIGSUSPEND3
2875
2876config COMPAT
2877	def_bool y
2878	depends on IA32_EMULATION || X86_X32
2879
2880if COMPAT
2881config COMPAT_FOR_U64_ALIGNMENT
2882	def_bool y
2883
2884config SYSVIPC_COMPAT
2885	def_bool y
2886	depends on SYSVIPC
2887endif
2888
2889endmenu
2890
2891
2892config HAVE_ATOMIC_IOMAP
2893	def_bool y
2894	depends on X86_32
2895
2896source "arch/x86/kvm/Kconfig"
2897
2898source "arch/x86/Kconfig.assembler"
2899