xref: /openbmc/linux/arch/x86/Kconfig (revision d9565bf4)
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 X86_INTEL_MEMORY_PROTECTION_KEYS
1865	prompt "Memory Protection Keys"
1866	def_bool y
1867	# Note: only available in 64-bit mode
1868	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1869	select ARCH_USES_HIGH_VMA_FLAGS
1870	select ARCH_HAS_PKEYS
1871	help
1872	  Memory Protection Keys provides a mechanism for enforcing
1873	  page-based protections, but without requiring modification of the
1874	  page tables when an application changes protection domains.
1875
1876	  For details, see Documentation/core-api/protection-keys.rst
1877
1878	  If unsure, say y.
1879
1880choice
1881	prompt "TSX enable mode"
1882	depends on CPU_SUP_INTEL
1883	default X86_INTEL_TSX_MODE_OFF
1884	help
1885	  Intel's TSX (Transactional Synchronization Extensions) feature
1886	  allows to optimize locking protocols through lock elision which
1887	  can lead to a noticeable performance boost.
1888
1889	  On the other hand it has been shown that TSX can be exploited
1890	  to form side channel attacks (e.g. TAA) and chances are there
1891	  will be more of those attacks discovered in the future.
1892
1893	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1894	  might override this decision by tsx=on the command line parameter.
1895	  Even with TSX enabled, the kernel will attempt to enable the best
1896	  possible TAA mitigation setting depending on the microcode available
1897	  for the particular machine.
1898
1899	  This option allows to set the default tsx mode between tsx=on, =off
1900	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1901	  details.
1902
1903	  Say off if not sure, auto if TSX is in use but it should be used on safe
1904	  platforms or on if TSX is in use and the security aspect of tsx is not
1905	  relevant.
1906
1907config X86_INTEL_TSX_MODE_OFF
1908	bool "off"
1909	help
1910	  TSX is disabled if possible - equals to tsx=off command line parameter.
1911
1912config X86_INTEL_TSX_MODE_ON
1913	bool "on"
1914	help
1915	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1916	  line parameter.
1917
1918config X86_INTEL_TSX_MODE_AUTO
1919	bool "auto"
1920	help
1921	  TSX is enabled on TSX capable HW that is believed to be safe against
1922	  side channel attacks- equals the tsx=auto command line parameter.
1923endchoice
1924
1925config X86_SGX
1926	bool "Software Guard eXtensions (SGX)"
1927	depends on X86_64 && CPU_SUP_INTEL
1928	depends on CRYPTO=y
1929	depends on CRYPTO_SHA256=y
1930	select SRCU
1931	select MMU_NOTIFIER
1932	select NUMA_KEEP_MEMINFO if NUMA
1933	select XARRAY_MULTI
1934	help
1935	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1936	  that can be used by applications to set aside private regions of code
1937	  and data, referred to as enclaves. An enclave's private memory can
1938	  only be accessed by code running within the enclave. Accesses from
1939	  outside the enclave, including other enclaves, are disallowed by
1940	  hardware.
1941
1942	  If unsure, say N.
1943
1944config EFI
1945	bool "EFI runtime service support"
1946	depends on ACPI
1947	select UCS2_STRING
1948	select EFI_RUNTIME_WRAPPERS
1949	select ARCH_USE_MEMREMAP_PROT
1950	help
1951	  This enables the kernel to use EFI runtime services that are
1952	  available (such as the EFI variable services).
1953
1954	  This option is only useful on systems that have EFI firmware.
1955	  In addition, you should use the latest ELILO loader available
1956	  at <http://elilo.sourceforge.net> in order to take advantage
1957	  of EFI runtime services. However, even with this option, the
1958	  resultant kernel should continue to boot on existing non-EFI
1959	  platforms.
1960
1961config EFI_STUB
1962	bool "EFI stub support"
1963	depends on EFI
1964	depends on $(cc-option,-mabi=ms) || X86_32
1965	select RELOCATABLE
1966	help
1967	  This kernel feature allows a bzImage to be loaded directly
1968	  by EFI firmware without the use of a bootloader.
1969
1970	  See Documentation/admin-guide/efi-stub.rst for more information.
1971
1972config EFI_MIXED
1973	bool "EFI mixed-mode support"
1974	depends on EFI_STUB && X86_64
1975	help
1976	   Enabling this feature allows a 64-bit kernel to be booted
1977	   on a 32-bit firmware, provided that your CPU supports 64-bit
1978	   mode.
1979
1980	   Note that it is not possible to boot a mixed-mode enabled
1981	   kernel via the EFI boot stub - a bootloader that supports
1982	   the EFI handover protocol must be used.
1983
1984	   If unsure, say N.
1985
1986source "kernel/Kconfig.hz"
1987
1988config KEXEC
1989	bool "kexec system call"
1990	select KEXEC_CORE
1991	help
1992	  kexec is a system call that implements the ability to shutdown your
1993	  current kernel, and to start another kernel.  It is like a reboot
1994	  but it is independent of the system firmware.   And like a reboot
1995	  you can start any kernel with it, not just Linux.
1996
1997	  The name comes from the similarity to the exec system call.
1998
1999	  It is an ongoing process to be certain the hardware in a machine
2000	  is properly shutdown, so do not be surprised if this code does not
2001	  initially work for you.  As of this writing the exact hardware
2002	  interface is strongly in flux, so no good recommendation can be
2003	  made.
2004
2005config KEXEC_FILE
2006	bool "kexec file based system call"
2007	select KEXEC_CORE
2008	select BUILD_BIN2C
2009	depends on X86_64
2010	depends on CRYPTO=y
2011	depends on CRYPTO_SHA256=y
2012	help
2013	  This is new version of kexec system call. This system call is
2014	  file based and takes file descriptors as system call argument
2015	  for kernel and initramfs as opposed to list of segments as
2016	  accepted by previous system call.
2017
2018config ARCH_HAS_KEXEC_PURGATORY
2019	def_bool KEXEC_FILE
2020
2021config KEXEC_SIG
2022	bool "Verify kernel signature during kexec_file_load() syscall"
2023	depends on KEXEC_FILE
2024	help
2025
2026	  This option makes the kexec_file_load() syscall check for a valid
2027	  signature of the kernel image.  The image can still be loaded without
2028	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2029	  there's a signature that we can check, then it must be valid.
2030
2031	  In addition to this option, you need to enable signature
2032	  verification for the corresponding kernel image type being
2033	  loaded in order for this to work.
2034
2035config KEXEC_SIG_FORCE
2036	bool "Require a valid signature in kexec_file_load() syscall"
2037	depends on KEXEC_SIG
2038	help
2039	  This option makes kernel signature verification mandatory for
2040	  the kexec_file_load() syscall.
2041
2042config KEXEC_BZIMAGE_VERIFY_SIG
2043	bool "Enable bzImage signature verification support"
2044	depends on KEXEC_SIG
2045	depends on SIGNED_PE_FILE_VERIFICATION
2046	select SYSTEM_TRUSTED_KEYRING
2047	help
2048	  Enable bzImage signature verification support.
2049
2050config CRASH_DUMP
2051	bool "kernel crash dumps"
2052	depends on X86_64 || (X86_32 && HIGHMEM)
2053	help
2054	  Generate crash dump after being started by kexec.
2055	  This should be normally only set in special crash dump kernels
2056	  which are loaded in the main kernel with kexec-tools into
2057	  a specially reserved region and then later executed after
2058	  a crash by kdump/kexec. The crash dump kernel must be compiled
2059	  to a memory address not used by the main kernel or BIOS using
2060	  PHYSICAL_START, or it must be built as a relocatable image
2061	  (CONFIG_RELOCATABLE=y).
2062	  For more details see Documentation/admin-guide/kdump/kdump.rst
2063
2064config KEXEC_JUMP
2065	bool "kexec jump"
2066	depends on KEXEC && HIBERNATION
2067	help
2068	  Jump between original kernel and kexeced kernel and invoke
2069	  code in physical address mode via KEXEC
2070
2071config PHYSICAL_START
2072	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2073	default "0x1000000"
2074	help
2075	  This gives the physical address where the kernel is loaded.
2076
2077	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2078	  bzImage will decompress itself to above physical address and
2079	  run from there. Otherwise, bzImage will run from the address where
2080	  it has been loaded by the boot loader and will ignore above physical
2081	  address.
2082
2083	  In normal kdump cases one does not have to set/change this option
2084	  as now bzImage can be compiled as a completely relocatable image
2085	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2086	  address. This option is mainly useful for the folks who don't want
2087	  to use a bzImage for capturing the crash dump and want to use a
2088	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2089	  to be specifically compiled to run from a specific memory area
2090	  (normally a reserved region) and this option comes handy.
2091
2092	  So if you are using bzImage for capturing the crash dump,
2093	  leave the value here unchanged to 0x1000000 and set
2094	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2095	  for capturing the crash dump change this value to start of
2096	  the reserved region.  In other words, it can be set based on
2097	  the "X" value as specified in the "crashkernel=YM@XM"
2098	  command line boot parameter passed to the panic-ed
2099	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2100	  for more details about crash dumps.
2101
2102	  Usage of bzImage for capturing the crash dump is recommended as
2103	  one does not have to build two kernels. Same kernel can be used
2104	  as production kernel and capture kernel. Above option should have
2105	  gone away after relocatable bzImage support is introduced. But it
2106	  is present because there are users out there who continue to use
2107	  vmlinux for dump capture. This option should go away down the
2108	  line.
2109
2110	  Don't change this unless you know what you are doing.
2111
2112config RELOCATABLE
2113	bool "Build a relocatable kernel"
2114	default y
2115	help
2116	  This builds a kernel image that retains relocation information
2117	  so it can be loaded someplace besides the default 1MB.
2118	  The relocations tend to make the kernel binary about 10% larger,
2119	  but are discarded at runtime.
2120
2121	  One use is for the kexec on panic case where the recovery kernel
2122	  must live at a different physical address than the primary
2123	  kernel.
2124
2125	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2126	  it has been loaded at and the compile time physical address
2127	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2128
2129config RANDOMIZE_BASE
2130	bool "Randomize the address of the kernel image (KASLR)"
2131	depends on RELOCATABLE
2132	default y
2133	help
2134	  In support of Kernel Address Space Layout Randomization (KASLR),
2135	  this randomizes the physical address at which the kernel image
2136	  is decompressed and the virtual address where the kernel
2137	  image is mapped, as a security feature that deters exploit
2138	  attempts relying on knowledge of the location of kernel
2139	  code internals.
2140
2141	  On 64-bit, the kernel physical and virtual addresses are
2142	  randomized separately. The physical address will be anywhere
2143	  between 16MB and the top of physical memory (up to 64TB). The
2144	  virtual address will be randomized from 16MB up to 1GB (9 bits
2145	  of entropy). Note that this also reduces the memory space
2146	  available to kernel modules from 1.5GB to 1GB.
2147
2148	  On 32-bit, the kernel physical and virtual addresses are
2149	  randomized together. They will be randomized from 16MB up to
2150	  512MB (8 bits of entropy).
2151
2152	  Entropy is generated using the RDRAND instruction if it is
2153	  supported. If RDTSC is supported, its value is mixed into
2154	  the entropy pool as well. If neither RDRAND nor RDTSC are
2155	  supported, then entropy is read from the i8254 timer. The
2156	  usable entropy is limited by the kernel being built using
2157	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2158	  minimum of 2MB. As a result, only 10 bits of entropy are
2159	  theoretically possible, but the implementations are further
2160	  limited due to memory layouts.
2161
2162	  If unsure, say Y.
2163
2164# Relocation on x86 needs some additional build support
2165config X86_NEED_RELOCS
2166	def_bool y
2167	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2168
2169config PHYSICAL_ALIGN
2170	hex "Alignment value to which kernel should be aligned"
2171	default "0x200000"
2172	range 0x2000 0x1000000 if X86_32
2173	range 0x200000 0x1000000 if X86_64
2174	help
2175	  This value puts the alignment restrictions on physical address
2176	  where kernel is loaded and run from. Kernel is compiled for an
2177	  address which meets above alignment restriction.
2178
2179	  If bootloader loads the kernel at a non-aligned address and
2180	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2181	  address aligned to above value and run from there.
2182
2183	  If bootloader loads the kernel at a non-aligned address and
2184	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2185	  load address and decompress itself to the address it has been
2186	  compiled for and run from there. The address for which kernel is
2187	  compiled already meets above alignment restrictions. Hence the
2188	  end result is that kernel runs from a physical address meeting
2189	  above alignment restrictions.
2190
2191	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2192	  this value must be a multiple of 0x200000.
2193
2194	  Don't change this unless you know what you are doing.
2195
2196config DYNAMIC_MEMORY_LAYOUT
2197	bool
2198	help
2199	  This option makes base addresses of vmalloc and vmemmap as well as
2200	  __PAGE_OFFSET movable during boot.
2201
2202config RANDOMIZE_MEMORY
2203	bool "Randomize the kernel memory sections"
2204	depends on X86_64
2205	depends on RANDOMIZE_BASE
2206	select DYNAMIC_MEMORY_LAYOUT
2207	default RANDOMIZE_BASE
2208	help
2209	   Randomizes the base virtual address of kernel memory sections
2210	   (physical memory mapping, vmalloc & vmemmap). This security feature
2211	   makes exploits relying on predictable memory locations less reliable.
2212
2213	   The order of allocations remains unchanged. Entropy is generated in
2214	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2215	   configuration have in average 30,000 different possible virtual
2216	   addresses for each memory section.
2217
2218	   If unsure, say Y.
2219
2220config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2221	hex "Physical memory mapping padding" if EXPERT
2222	depends on RANDOMIZE_MEMORY
2223	default "0xa" if MEMORY_HOTPLUG
2224	default "0x0"
2225	range 0x1 0x40 if MEMORY_HOTPLUG
2226	range 0x0 0x40
2227	help
2228	   Define the padding in terabytes added to the existing physical
2229	   memory size during kernel memory randomization. It is useful
2230	   for memory hotplug support but reduces the entropy available for
2231	   address randomization.
2232
2233	   If unsure, leave at the default value.
2234
2235config HOTPLUG_CPU
2236	def_bool y
2237	depends on SMP
2238
2239config BOOTPARAM_HOTPLUG_CPU0
2240	bool "Set default setting of cpu0_hotpluggable"
2241	depends on HOTPLUG_CPU
2242	help
2243	  Set whether default state of cpu0_hotpluggable is on or off.
2244
2245	  Say Y here to enable CPU0 hotplug by default. If this switch
2246	  is turned on, there is no need to give cpu0_hotplug kernel
2247	  parameter and the CPU0 hotplug feature is enabled by default.
2248
2249	  Please note: there are two known CPU0 dependencies if you want
2250	  to enable the CPU0 hotplug feature either by this switch or by
2251	  cpu0_hotplug kernel parameter.
2252
2253	  First, resume from hibernate or suspend always starts from CPU0.
2254	  So hibernate and suspend are prevented if CPU0 is offline.
2255
2256	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2257	  offline if any interrupt can not migrate out of CPU0. There may
2258	  be other CPU0 dependencies.
2259
2260	  Please make sure the dependencies are under your control before
2261	  you enable this feature.
2262
2263	  Say N if you don't want to enable CPU0 hotplug feature by default.
2264	  You still can enable the CPU0 hotplug feature at boot by kernel
2265	  parameter cpu0_hotplug.
2266
2267config DEBUG_HOTPLUG_CPU0
2268	def_bool n
2269	prompt "Debug CPU0 hotplug"
2270	depends on HOTPLUG_CPU
2271	help
2272	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2273	  soon as possible and boots up userspace with CPU0 offlined. User
2274	  can online CPU0 back after boot time.
2275
2276	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2277	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2278	  compilation or giving cpu0_hotplug kernel parameter at boot.
2279
2280	  If unsure, say N.
2281
2282config COMPAT_VDSO
2283	def_bool n
2284	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2285	depends on COMPAT_32
2286	help
2287	  Certain buggy versions of glibc will crash if they are
2288	  presented with a 32-bit vDSO that is not mapped at the address
2289	  indicated in its segment table.
2290
2291	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2292	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2293	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2294	  the only released version with the bug, but OpenSUSE 9
2295	  contains a buggy "glibc 2.3.2".
2296
2297	  The symptom of the bug is that everything crashes on startup, saying:
2298	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2299
2300	  Saying Y here changes the default value of the vdso32 boot
2301	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2302	  This works around the glibc bug but hurts performance.
2303
2304	  If unsure, say N: if you are compiling your own kernel, you
2305	  are unlikely to be using a buggy version of glibc.
2306
2307choice
2308	prompt "vsyscall table for legacy applications"
2309	depends on X86_64
2310	default LEGACY_VSYSCALL_XONLY
2311	help
2312	  Legacy user code that does not know how to find the vDSO expects
2313	  to be able to issue three syscalls by calling fixed addresses in
2314	  kernel space. Since this location is not randomized with ASLR,
2315	  it can be used to assist security vulnerability exploitation.
2316
2317	  This setting can be changed at boot time via the kernel command
2318	  line parameter vsyscall=[emulate|xonly|none].
2319
2320	  On a system with recent enough glibc (2.14 or newer) and no
2321	  static binaries, you can say None without a performance penalty
2322	  to improve security.
2323
2324	  If unsure, select "Emulate execution only".
2325
2326	config LEGACY_VSYSCALL_EMULATE
2327		bool "Full emulation"
2328		help
2329		  The kernel traps and emulates calls into the fixed vsyscall
2330		  address mapping. This makes the mapping non-executable, but
2331		  it still contains readable known contents, which could be
2332		  used in certain rare security vulnerability exploits. This
2333		  configuration is recommended when using legacy userspace
2334		  that still uses vsyscalls along with legacy binary
2335		  instrumentation tools that require code to be readable.
2336
2337		  An example of this type of legacy userspace is running
2338		  Pin on an old binary that still uses vsyscalls.
2339
2340	config LEGACY_VSYSCALL_XONLY
2341		bool "Emulate execution only"
2342		help
2343		  The kernel traps and emulates calls into the fixed vsyscall
2344		  address mapping and does not allow reads.  This
2345		  configuration is recommended when userspace might use the
2346		  legacy vsyscall area but support for legacy binary
2347		  instrumentation of legacy code is not needed.  It mitigates
2348		  certain uses of the vsyscall area as an ASLR-bypassing
2349		  buffer.
2350
2351	config LEGACY_VSYSCALL_NONE
2352		bool "None"
2353		help
2354		  There will be no vsyscall mapping at all. This will
2355		  eliminate any risk of ASLR bypass due to the vsyscall
2356		  fixed address mapping. Attempts to use the vsyscalls
2357		  will be reported to dmesg, so that either old or
2358		  malicious userspace programs can be identified.
2359
2360endchoice
2361
2362config CMDLINE_BOOL
2363	bool "Built-in kernel command line"
2364	help
2365	  Allow for specifying boot arguments to the kernel at
2366	  build time.  On some systems (e.g. embedded ones), it is
2367	  necessary or convenient to provide some or all of the
2368	  kernel boot arguments with the kernel itself (that is,
2369	  to not rely on the boot loader to provide them.)
2370
2371	  To compile command line arguments into the kernel,
2372	  set this option to 'Y', then fill in the
2373	  boot arguments in CONFIG_CMDLINE.
2374
2375	  Systems with fully functional boot loaders (i.e. non-embedded)
2376	  should leave this option set to 'N'.
2377
2378config CMDLINE
2379	string "Built-in kernel command string"
2380	depends on CMDLINE_BOOL
2381	default ""
2382	help
2383	  Enter arguments here that should be compiled into the kernel
2384	  image and used at boot time.  If the boot loader provides a
2385	  command line at boot time, it is appended to this string to
2386	  form the full kernel command line, when the system boots.
2387
2388	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2389	  change this behavior.
2390
2391	  In most cases, the command line (whether built-in or provided
2392	  by the boot loader) should specify the device for the root
2393	  file system.
2394
2395config CMDLINE_OVERRIDE
2396	bool "Built-in command line overrides boot loader arguments"
2397	depends on CMDLINE_BOOL && CMDLINE != ""
2398	help
2399	  Set this option to 'Y' to have the kernel ignore the boot loader
2400	  command line, and use ONLY the built-in command line.
2401
2402	  This is used to work around broken boot loaders.  This should
2403	  be set to 'N' under normal conditions.
2404
2405config MODIFY_LDT_SYSCALL
2406	bool "Enable the LDT (local descriptor table)" if EXPERT
2407	default y
2408	help
2409	  Linux can allow user programs to install a per-process x86
2410	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2411	  call.  This is required to run 16-bit or segmented code such as
2412	  DOSEMU or some Wine programs.  It is also used by some very old
2413	  threading libraries.
2414
2415	  Enabling this feature adds a small amount of overhead to
2416	  context switches and increases the low-level kernel attack
2417	  surface.  Disabling it removes the modify_ldt(2) system call.
2418
2419	  Saying 'N' here may make sense for embedded or server kernels.
2420
2421config STRICT_SIGALTSTACK_SIZE
2422	bool "Enforce strict size checking for sigaltstack"
2423	depends on DYNAMIC_SIGFRAME
2424	help
2425	  For historical reasons MINSIGSTKSZ is a constant which became
2426	  already too small with AVX512 support. Add a mechanism to
2427	  enforce strict checking of the sigaltstack size against the
2428	  real size of the FPU frame. This option enables the check
2429	  by default. It can also be controlled via the kernel command
2430	  line option 'strict_sas_size' independent of this config
2431	  switch. Enabling it might break existing applications which
2432	  allocate a too small sigaltstack but 'work' because they
2433	  never get a signal delivered.
2434
2435	  Say 'N' unless you want to really enforce this check.
2436
2437source "kernel/livepatch/Kconfig"
2438
2439endmenu
2440
2441config ARCH_HAS_ADD_PAGES
2442	def_bool y
2443	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2444
2445config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2446	def_bool y
2447
2448menu "Power management and ACPI options"
2449
2450config ARCH_HIBERNATION_HEADER
2451	def_bool y
2452	depends on HIBERNATION
2453
2454source "kernel/power/Kconfig"
2455
2456source "drivers/acpi/Kconfig"
2457
2458config X86_APM_BOOT
2459	def_bool y
2460	depends on APM
2461
2462menuconfig APM
2463	tristate "APM (Advanced Power Management) BIOS support"
2464	depends on X86_32 && PM_SLEEP
2465	help
2466	  APM is a BIOS specification for saving power using several different
2467	  techniques. This is mostly useful for battery powered laptops with
2468	  APM compliant BIOSes. If you say Y here, the system time will be
2469	  reset after a RESUME operation, the /proc/apm device will provide
2470	  battery status information, and user-space programs will receive
2471	  notification of APM "events" (e.g. battery status change).
2472
2473	  If you select "Y" here, you can disable actual use of the APM
2474	  BIOS by passing the "apm=off" option to the kernel at boot time.
2475
2476	  Note that the APM support is almost completely disabled for
2477	  machines with more than one CPU.
2478
2479	  In order to use APM, you will need supporting software. For location
2480	  and more information, read <file:Documentation/power/apm-acpi.rst>
2481	  and the Battery Powered Linux mini-HOWTO, available from
2482	  <http://www.tldp.org/docs.html#howto>.
2483
2484	  This driver does not spin down disk drives (see the hdparm(8)
2485	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2486	  VESA-compliant "green" monitors.
2487
2488	  This driver does not support the TI 4000M TravelMate and the ACER
2489	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2490	  desktop machines also don't have compliant BIOSes, and this driver
2491	  may cause those machines to panic during the boot phase.
2492
2493	  Generally, if you don't have a battery in your machine, there isn't
2494	  much point in using this driver and you should say N. If you get
2495	  random kernel OOPSes or reboots that don't seem to be related to
2496	  anything, try disabling/enabling this option (or disabling/enabling
2497	  APM in your BIOS).
2498
2499	  Some other things you should try when experiencing seemingly random,
2500	  "weird" problems:
2501
2502	  1) make sure that you have enough swap space and that it is
2503	  enabled.
2504	  2) pass the "no-hlt" option to the kernel
2505	  3) switch on floating point emulation in the kernel and pass
2506	  the "no387" option to the kernel
2507	  4) pass the "floppy=nodma" option to the kernel
2508	  5) pass the "mem=4M" option to the kernel (thereby disabling
2509	  all but the first 4 MB of RAM)
2510	  6) make sure that the CPU is not over clocked.
2511	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2512	  8) disable the cache from your BIOS settings
2513	  9) install a fan for the video card or exchange video RAM
2514	  10) install a better fan for the CPU
2515	  11) exchange RAM chips
2516	  12) exchange the motherboard.
2517
2518	  To compile this driver as a module, choose M here: the
2519	  module will be called apm.
2520
2521if APM
2522
2523config APM_IGNORE_USER_SUSPEND
2524	bool "Ignore USER SUSPEND"
2525	help
2526	  This option will ignore USER SUSPEND requests. On machines with a
2527	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2528	  series notebooks, it is necessary to say Y because of a BIOS bug.
2529
2530config APM_DO_ENABLE
2531	bool "Enable PM at boot time"
2532	help
2533	  Enable APM features at boot time. From page 36 of the APM BIOS
2534	  specification: "When disabled, the APM BIOS does not automatically
2535	  power manage devices, enter the Standby State, enter the Suspend
2536	  State, or take power saving steps in response to CPU Idle calls."
2537	  This driver will make CPU Idle calls when Linux is idle (unless this
2538	  feature is turned off -- see "Do CPU IDLE calls", below). This
2539	  should always save battery power, but more complicated APM features
2540	  will be dependent on your BIOS implementation. You may need to turn
2541	  this option off if your computer hangs at boot time when using APM
2542	  support, or if it beeps continuously instead of suspending. Turn
2543	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2544	  T400CDT. This is off by default since most machines do fine without
2545	  this feature.
2546
2547config APM_CPU_IDLE
2548	depends on CPU_IDLE
2549	bool "Make CPU Idle calls when idle"
2550	help
2551	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2552	  On some machines, this can activate improved power savings, such as
2553	  a slowed CPU clock rate, when the machine is idle. These idle calls
2554	  are made after the idle loop has run for some length of time (e.g.,
2555	  333 mS). On some machines, this will cause a hang at boot time or
2556	  whenever the CPU becomes idle. (On machines with more than one CPU,
2557	  this option does nothing.)
2558
2559config APM_DISPLAY_BLANK
2560	bool "Enable console blanking using APM"
2561	help
2562	  Enable console blanking using the APM. Some laptops can use this to
2563	  turn off the LCD backlight when the screen blanker of the Linux
2564	  virtual console blanks the screen. Note that this is only used by
2565	  the virtual console screen blanker, and won't turn off the backlight
2566	  when using the X Window system. This also doesn't have anything to
2567	  do with your VESA-compliant power-saving monitor. Further, this
2568	  option doesn't work for all laptops -- it might not turn off your
2569	  backlight at all, or it might print a lot of errors to the console,
2570	  especially if you are using gpm.
2571
2572config APM_ALLOW_INTS
2573	bool "Allow interrupts during APM BIOS calls"
2574	help
2575	  Normally we disable external interrupts while we are making calls to
2576	  the APM BIOS as a measure to lessen the effects of a badly behaving
2577	  BIOS implementation.  The BIOS should reenable interrupts if it
2578	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2579	  many of the newer IBM Thinkpads.  If you experience hangs when you
2580	  suspend, try setting this to Y.  Otherwise, say N.
2581
2582endif # APM
2583
2584source "drivers/cpufreq/Kconfig"
2585
2586source "drivers/cpuidle/Kconfig"
2587
2588source "drivers/idle/Kconfig"
2589
2590endmenu
2591
2592
2593menu "Bus options (PCI etc.)"
2594
2595choice
2596	prompt "PCI access mode"
2597	depends on X86_32 && PCI
2598	default PCI_GOANY
2599	help
2600	  On PCI systems, the BIOS can be used to detect the PCI devices and
2601	  determine their configuration. However, some old PCI motherboards
2602	  have BIOS bugs and may crash if this is done. Also, some embedded
2603	  PCI-based systems don't have any BIOS at all. Linux can also try to
2604	  detect the PCI hardware directly without using the BIOS.
2605
2606	  With this option, you can specify how Linux should detect the
2607	  PCI devices. If you choose "BIOS", the BIOS will be used,
2608	  if you choose "Direct", the BIOS won't be used, and if you
2609	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2610	  If you choose "Any", the kernel will try MMCONFIG, then the
2611	  direct access method and falls back to the BIOS if that doesn't
2612	  work. If unsure, go with the default, which is "Any".
2613
2614config PCI_GOBIOS
2615	bool "BIOS"
2616
2617config PCI_GOMMCONFIG
2618	bool "MMConfig"
2619
2620config PCI_GODIRECT
2621	bool "Direct"
2622
2623config PCI_GOOLPC
2624	bool "OLPC XO-1"
2625	depends on OLPC
2626
2627config PCI_GOANY
2628	bool "Any"
2629
2630endchoice
2631
2632config PCI_BIOS
2633	def_bool y
2634	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2635
2636# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2637config PCI_DIRECT
2638	def_bool y
2639	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2640
2641config PCI_MMCONFIG
2642	bool "Support mmconfig PCI config space access" if X86_64
2643	default y
2644	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2645	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2646
2647config PCI_OLPC
2648	def_bool y
2649	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2650
2651config PCI_XEN
2652	def_bool y
2653	depends on PCI && XEN
2654
2655config MMCONF_FAM10H
2656	def_bool y
2657	depends on X86_64 && PCI_MMCONFIG && ACPI
2658
2659config PCI_CNB20LE_QUIRK
2660	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2661	depends on PCI
2662	help
2663	  Read the PCI windows out of the CNB20LE host bridge. This allows
2664	  PCI hotplug to work on systems with the CNB20LE chipset which do
2665	  not have ACPI.
2666
2667	  There's no public spec for this chipset, and this functionality
2668	  is known to be incomplete.
2669
2670	  You should say N unless you know you need this.
2671
2672config ISA_BUS
2673	bool "ISA bus support on modern systems" if EXPERT
2674	help
2675	  Expose ISA bus device drivers and options available for selection and
2676	  configuration. Enable this option if your target machine has an ISA
2677	  bus. ISA is an older system, displaced by PCI and newer bus
2678	  architectures -- if your target machine is modern, it probably does
2679	  not have an ISA bus.
2680
2681	  If unsure, say N.
2682
2683# x86_64 have no ISA slots, but can have ISA-style DMA.
2684config ISA_DMA_API
2685	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2686	default y
2687	help
2688	  Enables ISA-style DMA support for devices requiring such controllers.
2689	  If unsure, say Y.
2690
2691if X86_32
2692
2693config ISA
2694	bool "ISA support"
2695	help
2696	  Find out whether you have ISA slots on your motherboard.  ISA is the
2697	  name of a bus system, i.e. the way the CPU talks to the other stuff
2698	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2699	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2700	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2701
2702config SCx200
2703	tristate "NatSemi SCx200 support"
2704	help
2705	  This provides basic support for National Semiconductor's
2706	  (now AMD's) Geode processors.  The driver probes for the
2707	  PCI-IDs of several on-chip devices, so its a good dependency
2708	  for other scx200_* drivers.
2709
2710	  If compiled as a module, the driver is named scx200.
2711
2712config SCx200HR_TIMER
2713	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2714	depends on SCx200
2715	default y
2716	help
2717	  This driver provides a clocksource built upon the on-chip
2718	  27MHz high-resolution timer.  Its also a workaround for
2719	  NSC Geode SC-1100's buggy TSC, which loses time when the
2720	  processor goes idle (as is done by the scheduler).  The
2721	  other workaround is idle=poll boot option.
2722
2723config OLPC
2724	bool "One Laptop Per Child support"
2725	depends on !X86_PAE
2726	select GPIOLIB
2727	select OF
2728	select OF_PROMTREE
2729	select IRQ_DOMAIN
2730	select OLPC_EC
2731	help
2732	  Add support for detecting the unique features of the OLPC
2733	  XO hardware.
2734
2735config OLPC_XO1_PM
2736	bool "OLPC XO-1 Power Management"
2737	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2738	help
2739	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2740
2741config OLPC_XO1_RTC
2742	bool "OLPC XO-1 Real Time Clock"
2743	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2744	help
2745	  Add support for the XO-1 real time clock, which can be used as a
2746	  programmable wakeup source.
2747
2748config OLPC_XO1_SCI
2749	bool "OLPC XO-1 SCI extras"
2750	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2751	depends on INPUT=y
2752	select POWER_SUPPLY
2753	help
2754	  Add support for SCI-based features of the OLPC XO-1 laptop:
2755	   - EC-driven system wakeups
2756	   - Power button
2757	   - Ebook switch
2758	   - Lid switch
2759	   - AC adapter status updates
2760	   - Battery status updates
2761
2762config OLPC_XO15_SCI
2763	bool "OLPC XO-1.5 SCI extras"
2764	depends on OLPC && ACPI
2765	select POWER_SUPPLY
2766	help
2767	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2768	   - EC-driven system wakeups
2769	   - AC adapter status updates
2770	   - Battery status updates
2771
2772config ALIX
2773	bool "PCEngines ALIX System Support (LED setup)"
2774	select GPIOLIB
2775	help
2776	  This option enables system support for the PCEngines ALIX.
2777	  At present this just sets up LEDs for GPIO control on
2778	  ALIX2/3/6 boards.  However, other system specific setup should
2779	  get added here.
2780
2781	  Note: You must still enable the drivers for GPIO and LED support
2782	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2783
2784	  Note: You have to set alix.force=1 for boards with Award BIOS.
2785
2786config NET5501
2787	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2788	select GPIOLIB
2789	help
2790	  This option enables system support for the Soekris Engineering net5501.
2791
2792config GEOS
2793	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2794	select GPIOLIB
2795	depends on DMI
2796	help
2797	  This option enables system support for the Traverse Technologies GEOS.
2798
2799config TS5500
2800	bool "Technologic Systems TS-5500 platform support"
2801	depends on MELAN
2802	select CHECK_SIGNATURE
2803	select NEW_LEDS
2804	select LEDS_CLASS
2805	help
2806	  This option enables system support for the Technologic Systems TS-5500.
2807
2808endif # X86_32
2809
2810config AMD_NB
2811	def_bool y
2812	depends on CPU_SUP_AMD && PCI
2813
2814endmenu
2815
2816
2817menu "Binary Emulations"
2818
2819config IA32_EMULATION
2820	bool "IA32 Emulation"
2821	depends on X86_64
2822	select ARCH_WANT_OLD_COMPAT_IPC
2823	select BINFMT_ELF
2824	select COMPAT_OLD_SIGACTION
2825	help
2826	  Include code to run legacy 32-bit programs under a
2827	  64-bit kernel. You should likely turn this on, unless you're
2828	  100% sure that you don't have any 32-bit programs left.
2829
2830config IA32_AOUT
2831	tristate "IA32 a.out support"
2832	depends on IA32_EMULATION
2833	depends on BROKEN
2834	help
2835	  Support old a.out binaries in the 32bit emulation.
2836
2837config X86_X32
2838	bool "x32 ABI for 64-bit mode"
2839	depends on X86_64
2840	help
2841	  Include code to run binaries for the x32 native 32-bit ABI
2842	  for 64-bit processors.  An x32 process gets access to the
2843	  full 64-bit register file and wide data path while leaving
2844	  pointers at 32 bits for smaller memory footprint.
2845
2846	  You will need a recent binutils (2.22 or later) with
2847	  elf32_x86_64 support enabled to compile a kernel with this
2848	  option set.
2849
2850config COMPAT_32
2851	def_bool y
2852	depends on IA32_EMULATION || X86_32
2853	select HAVE_UID16
2854	select OLD_SIGSUSPEND3
2855
2856config COMPAT
2857	def_bool y
2858	depends on IA32_EMULATION || X86_X32
2859
2860if COMPAT
2861config COMPAT_FOR_U64_ALIGNMENT
2862	def_bool y
2863
2864config SYSVIPC_COMPAT
2865	def_bool y
2866	depends on SYSVIPC
2867endif
2868
2869endmenu
2870
2871
2872config HAVE_ATOMIC_IOMAP
2873	def_bool y
2874	depends on X86_32
2875
2876source "arch/x86/kvm/Kconfig"
2877
2878source "arch/x86/Kconfig.assembler"
2879