xref: /linux/arch/x86/Kconfig (revision 51c2ee6d121ceb31ab8d35aff4ce53007aefb455)
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
37config FORCE_DYNAMIC_FTRACE
38	def_bool y
39	depends on X86_32
40	depends on FUNCTION_TRACER
41	select DYNAMIC_FTRACE
42	help
43	 We keep the static function tracing (!DYNAMIC_FTRACE) around
44	 in order to test the non static function tracing in the
45	 generic code, as other architectures still use it. But we
46	 only need to keep it around for x86_64. No need to keep it
47	 for x86_32. For x86_32, force DYNAMIC_FTRACE.
48#
49# Arch settings
50#
51# ( Note that options that are marked 'if X86_64' could in principle be
52#   ported to 32-bit as well. )
53#
54config X86
55	def_bool y
56	#
57	# Note: keep this list sorted alphabetically
58	#
59	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
60	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
61	select ARCH_32BIT_OFF_T			if X86_32
62	select ARCH_CLOCKSOURCE_INIT
63	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
64	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 || (X86_32 && HIGHMEM)
65	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
66	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if X86_64 || X86_PAE
67	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
68	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
69	select ARCH_HAS_CACHE_LINE_SIZE
70	select ARCH_HAS_DEBUG_VIRTUAL
71	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
72	select ARCH_HAS_DEVMEM_IS_ALLOWED
73	select ARCH_HAS_EARLY_DEBUG		if KGDB
74	select ARCH_HAS_ELF_RANDOMIZE
75	select ARCH_HAS_FAST_MULTIPLIER
76	select ARCH_HAS_FILTER_PGPROT
77	select ARCH_HAS_FORTIFY_SOURCE
78	select ARCH_HAS_GCOV_PROFILE_ALL
79	select ARCH_HAS_KCOV			if X86_64 && STACK_VALIDATION
80	select ARCH_HAS_MEM_ENCRYPT
81	select ARCH_HAS_MEMBARRIER_SYNC_CORE
82	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
83	select ARCH_HAS_PMEM_API		if X86_64
84	select ARCH_HAS_PTE_DEVMAP		if X86_64
85	select ARCH_HAS_PTE_SPECIAL
86	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
87	select ARCH_HAS_COPY_MC			if X86_64
88	select ARCH_HAS_SET_MEMORY
89	select ARCH_HAS_SET_DIRECT_MAP
90	select ARCH_HAS_STRICT_KERNEL_RWX
91	select ARCH_HAS_STRICT_MODULE_RWX
92	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
93	select ARCH_HAS_SYSCALL_WRAPPER
94	select ARCH_HAS_UBSAN_SANITIZE_ALL
95	select ARCH_HAS_DEBUG_WX
96	select ARCH_HAVE_NMI_SAFE_CMPXCHG
97	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
98	select ARCH_MIGHT_HAVE_PC_PARPORT
99	select ARCH_MIGHT_HAVE_PC_SERIO
100	select ARCH_STACKWALK
101	select ARCH_SUPPORTS_ACPI
102	select ARCH_SUPPORTS_ATOMIC_RMW
103	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
104	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
105	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
106	select ARCH_SUPPORTS_LTO_CLANG
107	select ARCH_SUPPORTS_LTO_CLANG_THIN
108	select ARCH_USE_BUILTIN_BSWAP
109	select ARCH_USE_MEMTEST
110	select ARCH_USE_QUEUED_RWLOCKS
111	select ARCH_USE_QUEUED_SPINLOCKS
112	select ARCH_USE_SYM_ANNOTATIONS
113	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
114	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
115	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
116	select ARCH_WANTS_NO_INSTR
117	select ARCH_WANT_HUGE_PMD_SHARE
118	select ARCH_WANT_LD_ORPHAN_WARN
119	select ARCH_WANTS_THP_SWAP		if X86_64
120	select BUILDTIME_TABLE_SORT
121	select CLKEVT_I8253
122	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
123	select CLOCKSOURCE_WATCHDOG
124	select DCACHE_WORD_ACCESS
125	select EDAC_ATOMIC_SCRUB
126	select EDAC_SUPPORT
127	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
128	select GENERIC_CLOCKEVENTS_MIN_ADJUST
129	select GENERIC_CMOS_UPDATE
130	select GENERIC_CPU_AUTOPROBE
131	select GENERIC_CPU_VULNERABILITIES
132	select GENERIC_EARLY_IOREMAP
133	select GENERIC_ENTRY
134	select GENERIC_FIND_FIRST_BIT
135	select GENERIC_IOMAP
136	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
137	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
138	select GENERIC_IRQ_MIGRATION		if SMP
139	select GENERIC_IRQ_PROBE
140	select GENERIC_IRQ_RESERVATION_MODE
141	select GENERIC_IRQ_SHOW
142	select GENERIC_PENDING_IRQ		if SMP
143	select GENERIC_PTDUMP
144	select GENERIC_SMP_IDLE_THREAD
145	select GENERIC_STRNCPY_FROM_USER
146	select GENERIC_STRNLEN_USER
147	select GENERIC_TIME_VSYSCALL
148	select GENERIC_GETTIMEOFDAY
149	select GENERIC_VDSO_TIME_NS
150	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
151	select HARDIRQS_SW_RESEND
152	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
153	select HAVE_ACPI_APEI			if ACPI
154	select HAVE_ACPI_APEI_NMI		if ACPI
155	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
156	select HAVE_ARCH_AUDITSYSCALL
157	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
158	select HAVE_ARCH_JUMP_LABEL
159	select HAVE_ARCH_JUMP_LABEL_RELATIVE
160	select HAVE_ARCH_KASAN			if X86_64
161	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
162	select HAVE_ARCH_KFENCE
163	select HAVE_ARCH_KGDB
164	select HAVE_ARCH_MMAP_RND_BITS		if MMU
165	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
166	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
167	select HAVE_ARCH_PREL32_RELOCATIONS
168	select HAVE_ARCH_SECCOMP_FILTER
169	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
170	select HAVE_ARCH_STACKLEAK
171	select HAVE_ARCH_TRACEHOOK
172	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
173	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
174	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
175	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
176	select HAVE_ARCH_VMAP_STACK		if X86_64
177	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
178	select HAVE_ARCH_WITHIN_STACK_FRAMES
179	select HAVE_ASM_MODVERSIONS
180	select HAVE_CMPXCHG_DOUBLE
181	select HAVE_CMPXCHG_LOCAL
182	select HAVE_CONTEXT_TRACKING		if X86_64
183	select HAVE_CONTEXT_TRACKING_OFFSTACK	if HAVE_CONTEXT_TRACKING
184	select HAVE_C_RECORDMCOUNT
185	select HAVE_OBJTOOL_MCOUNT		if STACK_VALIDATION
186	select HAVE_DEBUG_KMEMLEAK
187	select HAVE_DMA_CONTIGUOUS
188	select HAVE_DYNAMIC_FTRACE
189	select HAVE_DYNAMIC_FTRACE_WITH_REGS
190	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
191	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
192	select HAVE_EBPF_JIT
193	select HAVE_EFFICIENT_UNALIGNED_ACCESS
194	select HAVE_EISA
195	select HAVE_EXIT_THREAD
196	select HAVE_FAST_GUP
197	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
198	select HAVE_FTRACE_MCOUNT_RECORD
199	select HAVE_FUNCTION_GRAPH_TRACER
200	select HAVE_FUNCTION_TRACER
201	select HAVE_GCC_PLUGINS
202	select HAVE_HW_BREAKPOINT
203	select HAVE_IDE
204	select HAVE_IOREMAP_PROT
205	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
206	select HAVE_IRQ_TIME_ACCOUNTING
207	select HAVE_KERNEL_BZIP2
208	select HAVE_KERNEL_GZIP
209	select HAVE_KERNEL_LZ4
210	select HAVE_KERNEL_LZMA
211	select HAVE_KERNEL_LZO
212	select HAVE_KERNEL_XZ
213	select HAVE_KERNEL_ZSTD
214	select HAVE_KPROBES
215	select HAVE_KPROBES_ON_FTRACE
216	select HAVE_FUNCTION_ERROR_INJECTION
217	select HAVE_KRETPROBES
218	select HAVE_KVM
219	select HAVE_LIVEPATCH			if X86_64
220	select HAVE_MIXED_BREAKPOINTS_REGS
221	select HAVE_MOD_ARCH_SPECIFIC
222	select HAVE_MOVE_PMD
223	select HAVE_MOVE_PUD
224	select HAVE_NMI
225	select HAVE_OPTPROBES
226	select HAVE_PCSPKR_PLATFORM
227	select HAVE_PERF_EVENTS
228	select HAVE_PERF_EVENTS_NMI
229	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
230	select HAVE_PCI
231	select HAVE_PERF_REGS
232	select HAVE_PERF_USER_STACK_DUMP
233	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
234	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
235	select HAVE_REGS_AND_STACK_ACCESS_API
236	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
237	select HAVE_FUNCTION_ARG_ACCESS_API
238	select HAVE_SOFTIRQ_ON_OWN_STACK
239	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
240	select HAVE_STACK_VALIDATION		if X86_64
241	select HAVE_STATIC_CALL
242	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
243	select HAVE_PREEMPT_DYNAMIC
244	select HAVE_RSEQ
245	select HAVE_SYSCALL_TRACEPOINTS
246	select HAVE_UNSTABLE_SCHED_CLOCK
247	select HAVE_USER_RETURN_NOTIFIER
248	select HAVE_GENERIC_VDSO
249	select HOTPLUG_SMT			if SMP
250	select IRQ_FORCED_THREADING
251	select NEED_SG_DMA_LENGTH
252	select PCI_DOMAINS			if PCI
253	select PCI_LOCKLESS_CONFIG		if PCI
254	select PERF_EVENTS
255	select RTC_LIB
256	select RTC_MC146818_LIB
257	select SPARSE_IRQ
258	select SRCU
259	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
260	select SYSCTL_EXCEPTION_TRACE
261	select THREAD_INFO_IN_TASK
262	select USER_STACKTRACE_SUPPORT
263	select VIRT_TO_BUS
264	select HAVE_ARCH_KCSAN			if X86_64
265	select X86_FEATURE_NAMES		if PROC_FS
266	select PROC_PID_ARCH_STATUS		if PROC_FS
267	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
268
269config INSTRUCTION_DECODER
270	def_bool y
271	depends on KPROBES || PERF_EVENTS || UPROBES
272
273config OUTPUT_FORMAT
274	string
275	default "elf32-i386" if X86_32
276	default "elf64-x86-64" if X86_64
277
278config LOCKDEP_SUPPORT
279	def_bool y
280
281config STACKTRACE_SUPPORT
282	def_bool y
283
284config MMU
285	def_bool y
286
287config ARCH_MMAP_RND_BITS_MIN
288	default 28 if 64BIT
289	default 8
290
291config ARCH_MMAP_RND_BITS_MAX
292	default 32 if 64BIT
293	default 16
294
295config ARCH_MMAP_RND_COMPAT_BITS_MIN
296	default 8
297
298config ARCH_MMAP_RND_COMPAT_BITS_MAX
299	default 16
300
301config SBUS
302	bool
303
304config GENERIC_ISA_DMA
305	def_bool y
306	depends on ISA_DMA_API
307
308config GENERIC_BUG
309	def_bool y
310	depends on BUG
311	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
312
313config GENERIC_BUG_RELATIVE_POINTERS
314	bool
315
316config ARCH_MAY_HAVE_PC_FDC
317	def_bool y
318	depends on ISA_DMA_API
319
320config GENERIC_CALIBRATE_DELAY
321	def_bool y
322
323config ARCH_HAS_CPU_RELAX
324	def_bool y
325
326config ARCH_HAS_FILTER_PGPROT
327	def_bool y
328
329config HAVE_SETUP_PER_CPU_AREA
330	def_bool y
331
332config NEED_PER_CPU_EMBED_FIRST_CHUNK
333	def_bool y
334
335config NEED_PER_CPU_PAGE_FIRST_CHUNK
336	def_bool y
337
338config ARCH_HIBERNATION_POSSIBLE
339	def_bool y
340
341config ARCH_SUSPEND_POSSIBLE
342	def_bool y
343
344config ARCH_WANT_GENERAL_HUGETLB
345	def_bool y
346
347config ZONE_DMA32
348	def_bool y if X86_64
349
350config AUDIT_ARCH
351	def_bool y if X86_64
352
353config KASAN_SHADOW_OFFSET
354	hex
355	depends on KASAN
356	default 0xdffffc0000000000
357
358config HAVE_INTEL_TXT
359	def_bool y
360	depends on INTEL_IOMMU && ACPI
361
362config X86_32_SMP
363	def_bool y
364	depends on X86_32 && SMP
365
366config X86_64_SMP
367	def_bool y
368	depends on X86_64 && SMP
369
370config ARCH_SUPPORTS_UPROBES
371	def_bool y
372
373config FIX_EARLYCON_MEM
374	def_bool y
375
376config DYNAMIC_PHYSICAL_MASK
377	bool
378
379config PGTABLE_LEVELS
380	int
381	default 5 if X86_5LEVEL
382	default 4 if X86_64
383	default 3 if X86_PAE
384	default 2
385
386config CC_HAS_SANE_STACKPROTECTOR
387	bool
388	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
389	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
390	help
391	   We have to make sure stack protector is unconditionally disabled if
392	   the compiler produces broken code or if it does not let us control
393	   the segment on 32-bit kernels.
394
395menu "Processor type and features"
396
397config ZONE_DMA
398	bool "DMA memory allocation support" if EXPERT
399	default y
400	help
401	  DMA memory allocation support allows devices with less than 32-bit
402	  addressing to allocate within the first 16MB of address space.
403	  Disable if no such devices will be used.
404
405	  If unsure, say Y.
406
407config SMP
408	bool "Symmetric multi-processing support"
409	help
410	  This enables support for systems with more than one CPU. If you have
411	  a system with only one CPU, say N. If you have a system with more
412	  than one CPU, say Y.
413
414	  If you say N here, the kernel will run on uni- and multiprocessor
415	  machines, but will use only one CPU of a multiprocessor machine. If
416	  you say Y here, the kernel will run on many, but not all,
417	  uniprocessor machines. On a uniprocessor machine, the kernel
418	  will run faster if you say N here.
419
420	  Note that if you say Y here and choose architecture "586" or
421	  "Pentium" under "Processor family", the kernel will not work on 486
422	  architectures. Similarly, multiprocessor kernels for the "PPro"
423	  architecture may not work on all Pentium based boards.
424
425	  People using multiprocessor machines who say Y here should also say
426	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
427	  Management" code will be disabled if you say Y here.
428
429	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
430	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
431	  <http://www.tldp.org/docs.html#howto>.
432
433	  If you don't know what to do here, say N.
434
435config X86_FEATURE_NAMES
436	bool "Processor feature human-readable names" if EMBEDDED
437	default y
438	help
439	  This option compiles in a table of x86 feature bits and corresponding
440	  names.  This is required to support /proc/cpuinfo and a few kernel
441	  messages.  You can disable this to save space, at the expense of
442	  making those few kernel messages show numeric feature bits instead.
443
444	  If in doubt, say Y.
445
446config X86_X2APIC
447	bool "Support x2apic"
448	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
449	help
450	  This enables x2apic support on CPUs that have this feature.
451
452	  This allows 32-bit apic IDs (so it can support very large systems),
453	  and accesses the local apic via MSRs not via mmio.
454
455	  If you don't know what to do here, say N.
456
457config X86_MPPARSE
458	bool "Enable MPS table" if ACPI
459	default y
460	depends on X86_LOCAL_APIC
461	help
462	  For old smp systems that do not have proper acpi support. Newer systems
463	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
464
465config GOLDFISH
466	def_bool y
467	depends on X86_GOLDFISH
468
469config RETPOLINE
470	bool "Avoid speculative indirect branches in kernel"
471	default y
472	help
473	  Compile kernel with the retpoline compiler options to guard against
474	  kernel-to-user data leaks by avoiding speculative indirect
475	  branches. Requires a compiler with -mindirect-branch=thunk-extern
476	  support for full protection. The kernel may run slower.
477
478config X86_CPU_RESCTRL
479	bool "x86 CPU resource control support"
480	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
481	select KERNFS
482	select PROC_CPU_RESCTRL		if PROC_FS
483	help
484	  Enable x86 CPU resource control support.
485
486	  Provide support for the allocation and monitoring of system resources
487	  usage by the CPU.
488
489	  Intel calls this Intel Resource Director Technology
490	  (Intel(R) RDT). More information about RDT can be found in the
491	  Intel x86 Architecture Software Developer Manual.
492
493	  AMD calls this AMD Platform Quality of Service (AMD QoS).
494	  More information about AMD QoS can be found in the AMD64 Technology
495	  Platform Quality of Service Extensions manual.
496
497	  Say N if unsure.
498
499if X86_32
500config X86_BIGSMP
501	bool "Support for big SMP systems with more than 8 CPUs"
502	depends on SMP
503	help
504	  This option is needed for the systems that have more than 8 CPUs.
505
506config X86_EXTENDED_PLATFORM
507	bool "Support for extended (non-PC) x86 platforms"
508	default y
509	help
510	  If you disable this option then the kernel will only support
511	  standard PC platforms. (which covers the vast majority of
512	  systems out there.)
513
514	  If you enable this option then you'll be able to select support
515	  for the following (non-PC) 32 bit x86 platforms:
516		Goldfish (Android emulator)
517		AMD Elan
518		RDC R-321x SoC
519		SGI 320/540 (Visual Workstation)
520		STA2X11-based (e.g. Northville)
521		Moorestown MID devices
522
523	  If you have one of these systems, or if you want to build a
524	  generic distribution kernel, say Y here - otherwise say N.
525endif
526
527if X86_64
528config X86_EXTENDED_PLATFORM
529	bool "Support for extended (non-PC) x86 platforms"
530	default y
531	help
532	  If you disable this option then the kernel will only support
533	  standard PC platforms. (which covers the vast majority of
534	  systems out there.)
535
536	  If you enable this option then you'll be able to select support
537	  for the following (non-PC) 64 bit x86 platforms:
538		Numascale NumaChip
539		ScaleMP vSMP
540		SGI Ultraviolet
541
542	  If you have one of these systems, or if you want to build a
543	  generic distribution kernel, say Y here - otherwise say N.
544endif
545# This is an alphabetically sorted list of 64 bit extended platforms
546# Please maintain the alphabetic order if and when there are additions
547config X86_NUMACHIP
548	bool "Numascale NumaChip"
549	depends on X86_64
550	depends on X86_EXTENDED_PLATFORM
551	depends on NUMA
552	depends on SMP
553	depends on X86_X2APIC
554	depends on PCI_MMCONFIG
555	help
556	  Adds support for Numascale NumaChip large-SMP systems. Needed to
557	  enable more than ~168 cores.
558	  If you don't have one of these, you should say N here.
559
560config X86_VSMP
561	bool "ScaleMP vSMP"
562	select HYPERVISOR_GUEST
563	select PARAVIRT
564	depends on X86_64 && PCI
565	depends on X86_EXTENDED_PLATFORM
566	depends on SMP
567	help
568	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
569	  supposed to run on these EM64T-based machines.  Only choose this option
570	  if you have one of these machines.
571
572config X86_UV
573	bool "SGI Ultraviolet"
574	depends on X86_64
575	depends on X86_EXTENDED_PLATFORM
576	depends on NUMA
577	depends on EFI
578	depends on KEXEC_CORE
579	depends on X86_X2APIC
580	depends on PCI
581	help
582	  This option is needed in order to support SGI Ultraviolet systems.
583	  If you don't have one of these, you should say N here.
584
585# Following is an alphabetically sorted list of 32 bit extended platforms
586# Please maintain the alphabetic order if and when there are additions
587
588config X86_GOLDFISH
589	bool "Goldfish (Virtual Platform)"
590	depends on X86_EXTENDED_PLATFORM
591	help
592	 Enable support for the Goldfish virtual platform used primarily
593	 for Android development. Unless you are building for the Android
594	 Goldfish emulator say N here.
595
596config X86_INTEL_CE
597	bool "CE4100 TV platform"
598	depends on PCI
599	depends on PCI_GODIRECT
600	depends on X86_IO_APIC
601	depends on X86_32
602	depends on X86_EXTENDED_PLATFORM
603	select X86_REBOOTFIXUPS
604	select OF
605	select OF_EARLY_FLATTREE
606	help
607	  Select for the Intel CE media processor (CE4100) SOC.
608	  This option compiles in support for the CE4100 SOC for settop
609	  boxes and media devices.
610
611config X86_INTEL_MID
612	bool "Intel MID platform support"
613	depends on X86_EXTENDED_PLATFORM
614	depends on X86_PLATFORM_DEVICES
615	depends on PCI
616	depends on X86_64 || (PCI_GOANY && X86_32)
617	depends on X86_IO_APIC
618	select I2C
619	select DW_APB_TIMER
620	select APB_TIMER
621	select INTEL_SCU_PCI
622	select MFD_INTEL_MSIC
623	help
624	  Select to build a kernel capable of supporting Intel MID (Mobile
625	  Internet Device) platform systems which do not have the PCI legacy
626	  interfaces. If you are building for a PC class system say N here.
627
628	  Intel MID platforms are based on an Intel processor and chipset which
629	  consume less power than most of the x86 derivatives.
630
631config X86_INTEL_QUARK
632	bool "Intel Quark platform support"
633	depends on X86_32
634	depends on X86_EXTENDED_PLATFORM
635	depends on X86_PLATFORM_DEVICES
636	depends on X86_TSC
637	depends on PCI
638	depends on PCI_GOANY
639	depends on X86_IO_APIC
640	select IOSF_MBI
641	select INTEL_IMR
642	select COMMON_CLK
643	help
644	  Select to include support for Quark X1000 SoC.
645	  Say Y here if you have a Quark based system such as the Arduino
646	  compatible Intel Galileo.
647
648config X86_INTEL_LPSS
649	bool "Intel Low Power Subsystem Support"
650	depends on X86 && ACPI && PCI
651	select COMMON_CLK
652	select PINCTRL
653	select IOSF_MBI
654	help
655	  Select to build support for Intel Low Power Subsystem such as
656	  found on Intel Lynxpoint PCH. Selecting this option enables
657	  things like clock tree (common clock framework) and pincontrol
658	  which are needed by the LPSS peripheral drivers.
659
660config X86_AMD_PLATFORM_DEVICE
661	bool "AMD ACPI2Platform devices support"
662	depends on ACPI
663	select COMMON_CLK
664	select PINCTRL
665	help
666	  Select to interpret AMD specific ACPI device to platform device
667	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
668	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
669	  implemented under PINCTRL subsystem.
670
671config IOSF_MBI
672	tristate "Intel SoC IOSF Sideband support for SoC platforms"
673	depends on PCI
674	help
675	  This option enables sideband register access support for Intel SoC
676	  platforms. On these platforms the IOSF sideband is used in lieu of
677	  MSR's for some register accesses, mostly but not limited to thermal
678	  and power. Drivers may query the availability of this device to
679	  determine if they need the sideband in order to work on these
680	  platforms. The sideband is available on the following SoC products.
681	  This list is not meant to be exclusive.
682	   - BayTrail
683	   - Braswell
684	   - Quark
685
686	  You should say Y if you are running a kernel on one of these SoC's.
687
688config IOSF_MBI_DEBUG
689	bool "Enable IOSF sideband access through debugfs"
690	depends on IOSF_MBI && DEBUG_FS
691	help
692	  Select this option to expose the IOSF sideband access registers (MCR,
693	  MDR, MCRX) through debugfs to write and read register information from
694	  different units on the SoC. This is most useful for obtaining device
695	  state information for debug and analysis. As this is a general access
696	  mechanism, users of this option would have specific knowledge of the
697	  device they want to access.
698
699	  If you don't require the option or are in doubt, say N.
700
701config X86_RDC321X
702	bool "RDC R-321x SoC"
703	depends on X86_32
704	depends on X86_EXTENDED_PLATFORM
705	select M486
706	select X86_REBOOTFIXUPS
707	help
708	  This option is needed for RDC R-321x system-on-chip, also known
709	  as R-8610-(G).
710	  If you don't have one of these chips, you should say N here.
711
712config X86_32_NON_STANDARD
713	bool "Support non-standard 32-bit SMP architectures"
714	depends on X86_32 && SMP
715	depends on X86_EXTENDED_PLATFORM
716	help
717	  This option compiles in the bigsmp and STA2X11 default
718	  subarchitectures.  It is intended for a generic binary
719	  kernel. If you select them all, kernel will probe it one by
720	  one and will fallback to default.
721
722# Alphabetically sorted list of Non standard 32 bit platforms
723
724config X86_SUPPORTS_MEMORY_FAILURE
725	def_bool y
726	# MCE code calls memory_failure():
727	depends on X86_MCE
728	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
729	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
730	depends on X86_64 || !SPARSEMEM
731	select ARCH_SUPPORTS_MEMORY_FAILURE
732
733config STA2X11
734	bool "STA2X11 Companion Chip Support"
735	depends on X86_32_NON_STANDARD && PCI
736	select SWIOTLB
737	select MFD_STA2X11
738	select GPIOLIB
739	help
740	  This adds support for boards based on the STA2X11 IO-Hub,
741	  a.k.a. "ConneXt". The chip is used in place of the standard
742	  PC chipset, so all "standard" peripherals are missing. If this
743	  option is selected the kernel will still be able to boot on
744	  standard PC machines.
745
746config X86_32_IRIS
747	tristate "Eurobraille/Iris poweroff module"
748	depends on X86_32
749	help
750	  The Iris machines from EuroBraille do not have APM or ACPI support
751	  to shut themselves down properly.  A special I/O sequence is
752	  needed to do so, which is what this module does at
753	  kernel shutdown.
754
755	  This is only for Iris machines from EuroBraille.
756
757	  If unused, say N.
758
759config SCHED_OMIT_FRAME_POINTER
760	def_bool y
761	prompt "Single-depth WCHAN output"
762	depends on X86
763	help
764	  Calculate simpler /proc/<PID>/wchan values. If this option
765	  is disabled then wchan values will recurse back to the
766	  caller function. This provides more accurate wchan values,
767	  at the expense of slightly more scheduling overhead.
768
769	  If in doubt, say "Y".
770
771menuconfig HYPERVISOR_GUEST
772	bool "Linux guest support"
773	help
774	  Say Y here to enable options for running Linux under various hyper-
775	  visors. This option enables basic hypervisor detection and platform
776	  setup.
777
778	  If you say N, all options in this submenu will be skipped and
779	  disabled, and Linux guest support won't be built in.
780
781if HYPERVISOR_GUEST
782
783config PARAVIRT
784	bool "Enable paravirtualization code"
785	depends on HAVE_STATIC_CALL
786	help
787	  This changes the kernel so it can modify itself when it is run
788	  under a hypervisor, potentially improving performance significantly
789	  over full virtualization.  However, when run without a hypervisor
790	  the kernel is theoretically slower and slightly larger.
791
792config PARAVIRT_XXL
793	bool
794
795config PARAVIRT_DEBUG
796	bool "paravirt-ops debugging"
797	depends on PARAVIRT && DEBUG_KERNEL
798	help
799	  Enable to debug paravirt_ops internals.  Specifically, BUG if
800	  a paravirt_op is missing when it is called.
801
802config PARAVIRT_SPINLOCKS
803	bool "Paravirtualization layer for spinlocks"
804	depends on PARAVIRT && SMP
805	help
806	  Paravirtualized spinlocks allow a pvops backend to replace the
807	  spinlock implementation with something virtualization-friendly
808	  (for example, block the virtual CPU rather than spinning).
809
810	  It has a minimal impact on native kernels and gives a nice performance
811	  benefit on paravirtualized KVM / Xen kernels.
812
813	  If you are unsure how to answer this question, answer Y.
814
815config X86_HV_CALLBACK_VECTOR
816	def_bool n
817
818source "arch/x86/xen/Kconfig"
819
820config KVM_GUEST
821	bool "KVM Guest support (including kvmclock)"
822	depends on PARAVIRT
823	select PARAVIRT_CLOCK
824	select ARCH_CPUIDLE_HALTPOLL
825	select X86_HV_CALLBACK_VECTOR
826	default y
827	help
828	  This option enables various optimizations for running under the KVM
829	  hypervisor. It includes a paravirtualized clock, so that instead
830	  of relying on a PIT (or probably other) emulation by the
831	  underlying device model, the host provides the guest with
832	  timing infrastructure such as time of day, and system time
833
834config ARCH_CPUIDLE_HALTPOLL
835	def_bool n
836	prompt "Disable host haltpoll when loading haltpoll driver"
837	help
838	  If virtualized under KVM, disable host haltpoll.
839
840config PVH
841	bool "Support for running PVH guests"
842	help
843	  This option enables the PVH entry point for guest virtual machines
844	  as specified in the x86/HVM direct boot ABI.
845
846config PARAVIRT_TIME_ACCOUNTING
847	bool "Paravirtual steal time accounting"
848	depends on PARAVIRT
849	help
850	  Select this option to enable fine granularity task steal time
851	  accounting. Time spent executing other tasks in parallel with
852	  the current vCPU is discounted from the vCPU power. To account for
853	  that, there can be a small performance impact.
854
855	  If in doubt, say N here.
856
857config PARAVIRT_CLOCK
858	bool
859
860config JAILHOUSE_GUEST
861	bool "Jailhouse non-root cell support"
862	depends on X86_64 && PCI
863	select X86_PM_TIMER
864	help
865	  This option allows to run Linux as guest in a Jailhouse non-root
866	  cell. You can leave this option disabled if you only want to start
867	  Jailhouse and run Linux afterwards in the root cell.
868
869config ACRN_GUEST
870	bool "ACRN Guest support"
871	depends on X86_64
872	select X86_HV_CALLBACK_VECTOR
873	help
874	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
875	  a flexible, lightweight reference open-source hypervisor, built with
876	  real-time and safety-criticality in mind. It is built for embedded
877	  IOT with small footprint and real-time features. More details can be
878	  found in https://projectacrn.org/.
879
880endif #HYPERVISOR_GUEST
881
882source "arch/x86/Kconfig.cpu"
883
884config HPET_TIMER
885	def_bool X86_64
886	prompt "HPET Timer Support" if X86_32
887	help
888	  Use the IA-PC HPET (High Precision Event Timer) to manage
889	  time in preference to the PIT and RTC, if a HPET is
890	  present.
891	  HPET is the next generation timer replacing legacy 8254s.
892	  The HPET provides a stable time base on SMP
893	  systems, unlike the TSC, but it is more expensive to access,
894	  as it is off-chip.  The interface used is documented
895	  in the HPET spec, revision 1.
896
897	  You can safely choose Y here.  However, HPET will only be
898	  activated if the platform and the BIOS support this feature.
899	  Otherwise the 8254 will be used for timing services.
900
901	  Choose N to continue using the legacy 8254 timer.
902
903config HPET_EMULATE_RTC
904	def_bool y
905	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
906
907# Mark as expert because too many people got it wrong.
908# The code disables itself when not needed.
909config DMI
910	default y
911	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
912	bool "Enable DMI scanning" if EXPERT
913	help
914	  Enabled scanning of DMI to identify machine quirks. Say Y
915	  here unless you have verified that your setup is not
916	  affected by entries in the DMI blacklist. Required by PNP
917	  BIOS code.
918
919config GART_IOMMU
920	bool "Old AMD GART IOMMU support"
921	select DMA_OPS
922	select IOMMU_HELPER
923	select SWIOTLB
924	depends on X86_64 && PCI && AMD_NB
925	help
926	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
927	  GART based hardware IOMMUs.
928
929	  The GART supports full DMA access for devices with 32-bit access
930	  limitations, on systems with more than 3 GB. This is usually needed
931	  for USB, sound, many IDE/SATA chipsets and some other devices.
932
933	  Newer systems typically have a modern AMD IOMMU, supported via
934	  the CONFIG_AMD_IOMMU=y config option.
935
936	  In normal configurations this driver is only active when needed:
937	  there's more than 3 GB of memory and the system contains a
938	  32-bit limited device.
939
940	  If unsure, say Y.
941
942config MAXSMP
943	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
944	depends on X86_64 && SMP && DEBUG_KERNEL
945	select CPUMASK_OFFSTACK
946	help
947	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
948	  If unsure, say N.
949
950#
951# The maximum number of CPUs supported:
952#
953# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
954# and which can be configured interactively in the
955# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
956#
957# The ranges are different on 32-bit and 64-bit kernels, depending on
958# hardware capabilities and scalability features of the kernel.
959#
960# ( If MAXSMP is enabled we just use the highest possible value and disable
961#   interactive configuration. )
962#
963
964config NR_CPUS_RANGE_BEGIN
965	int
966	default NR_CPUS_RANGE_END if MAXSMP
967	default    1 if !SMP
968	default    2
969
970config NR_CPUS_RANGE_END
971	int
972	depends on X86_32
973	default   64 if  SMP &&  X86_BIGSMP
974	default    8 if  SMP && !X86_BIGSMP
975	default    1 if !SMP
976
977config NR_CPUS_RANGE_END
978	int
979	depends on X86_64
980	default 8192 if  SMP && CPUMASK_OFFSTACK
981	default  512 if  SMP && !CPUMASK_OFFSTACK
982	default    1 if !SMP
983
984config NR_CPUS_DEFAULT
985	int
986	depends on X86_32
987	default   32 if  X86_BIGSMP
988	default    8 if  SMP
989	default    1 if !SMP
990
991config NR_CPUS_DEFAULT
992	int
993	depends on X86_64
994	default 8192 if  MAXSMP
995	default   64 if  SMP
996	default    1 if !SMP
997
998config NR_CPUS
999	int "Maximum number of CPUs" if SMP && !MAXSMP
1000	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1001	default NR_CPUS_DEFAULT
1002	help
1003	  This allows you to specify the maximum number of CPUs which this
1004	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1005	  supported value is 8192, otherwise the maximum value is 512.  The
1006	  minimum value which makes sense is 2.
1007
1008	  This is purely to save memory: each supported CPU adds about 8KB
1009	  to the kernel image.
1010
1011config SCHED_SMT
1012	def_bool y if SMP
1013
1014config SCHED_MC
1015	def_bool y
1016	prompt "Multi-core scheduler support"
1017	depends on SMP
1018	help
1019	  Multi-core scheduler support improves the CPU scheduler's decision
1020	  making when dealing with multi-core CPU chips at a cost of slightly
1021	  increased overhead in some places. If unsure say N here.
1022
1023config SCHED_MC_PRIO
1024	bool "CPU core priorities scheduler support"
1025	depends on SCHED_MC && CPU_SUP_INTEL
1026	select X86_INTEL_PSTATE
1027	select CPU_FREQ
1028	default y
1029	help
1030	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1031	  core ordering determined at manufacturing time, which allows
1032	  certain cores to reach higher turbo frequencies (when running
1033	  single threaded workloads) than others.
1034
1035	  Enabling this kernel feature teaches the scheduler about
1036	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1037	  scheduler's CPU selection logic accordingly, so that higher
1038	  overall system performance can be achieved.
1039
1040	  This feature will have no effect on CPUs without this feature.
1041
1042	  If unsure say Y here.
1043
1044config UP_LATE_INIT
1045	def_bool y
1046	depends on !SMP && X86_LOCAL_APIC
1047
1048config X86_UP_APIC
1049	bool "Local APIC support on uniprocessors" if !PCI_MSI
1050	default PCI_MSI
1051	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1052	help
1053	  A local APIC (Advanced Programmable Interrupt Controller) is an
1054	  integrated interrupt controller in the CPU. If you have a single-CPU
1055	  system which has a processor with a local APIC, you can say Y here to
1056	  enable and use it. If you say Y here even though your machine doesn't
1057	  have a local APIC, then the kernel will still run with no slowdown at
1058	  all. The local APIC supports CPU-generated self-interrupts (timer,
1059	  performance counters), and the NMI watchdog which detects hard
1060	  lockups.
1061
1062config X86_UP_IOAPIC
1063	bool "IO-APIC support on uniprocessors"
1064	depends on X86_UP_APIC
1065	help
1066	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1067	  SMP-capable replacement for PC-style interrupt controllers. Most
1068	  SMP systems and many recent uniprocessor systems have one.
1069
1070	  If you have a single-CPU system with an IO-APIC, you can say Y here
1071	  to use it. If you say Y here even though your machine doesn't have
1072	  an IO-APIC, then the kernel will still run with no slowdown at all.
1073
1074config X86_LOCAL_APIC
1075	def_bool y
1076	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1077	select IRQ_DOMAIN_HIERARCHY
1078	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1079
1080config X86_IO_APIC
1081	def_bool y
1082	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1083
1084config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1085	bool "Reroute for broken boot IRQs"
1086	depends on X86_IO_APIC
1087	help
1088	  This option enables a workaround that fixes a source of
1089	  spurious interrupts. This is recommended when threaded
1090	  interrupt handling is used on systems where the generation of
1091	  superfluous "boot interrupts" cannot be disabled.
1092
1093	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1094	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1095	  kernel does during interrupt handling). On chipsets where this
1096	  boot IRQ generation cannot be disabled, this workaround keeps
1097	  the original IRQ line masked so that only the equivalent "boot
1098	  IRQ" is delivered to the CPUs. The workaround also tells the
1099	  kernel to set up the IRQ handler on the boot IRQ line. In this
1100	  way only one interrupt is delivered to the kernel. Otherwise
1101	  the spurious second interrupt may cause the kernel to bring
1102	  down (vital) interrupt lines.
1103
1104	  Only affects "broken" chipsets. Interrupt sharing may be
1105	  increased on these systems.
1106
1107config X86_MCE
1108	bool "Machine Check / overheating reporting"
1109	select GENERIC_ALLOCATOR
1110	default y
1111	help
1112	  Machine Check support allows the processor to notify the
1113	  kernel if it detects a problem (e.g. overheating, data corruption).
1114	  The action the kernel takes depends on the severity of the problem,
1115	  ranging from warning messages to halting the machine.
1116
1117config X86_MCELOG_LEGACY
1118	bool "Support for deprecated /dev/mcelog character device"
1119	depends on X86_MCE
1120	help
1121	  Enable support for /dev/mcelog which is needed by the old mcelog
1122	  userspace logging daemon. Consider switching to the new generation
1123	  rasdaemon solution.
1124
1125config X86_MCE_INTEL
1126	def_bool y
1127	prompt "Intel MCE features"
1128	depends on X86_MCE && X86_LOCAL_APIC
1129	help
1130	   Additional support for intel specific MCE features such as
1131	   the thermal monitor.
1132
1133config X86_MCE_AMD
1134	def_bool y
1135	prompt "AMD MCE features"
1136	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1137	help
1138	   Additional support for AMD specific MCE features such as
1139	   the DRAM Error Threshold.
1140
1141config X86_ANCIENT_MCE
1142	bool "Support for old Pentium 5 / WinChip machine checks"
1143	depends on X86_32 && X86_MCE
1144	help
1145	  Include support for machine check handling on old Pentium 5 or WinChip
1146	  systems. These typically need to be enabled explicitly on the command
1147	  line.
1148
1149config X86_MCE_THRESHOLD
1150	depends on X86_MCE_AMD || X86_MCE_INTEL
1151	def_bool y
1152
1153config X86_MCE_INJECT
1154	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1155	tristate "Machine check injector support"
1156	help
1157	  Provide support for injecting machine checks for testing purposes.
1158	  If you don't know what a machine check is and you don't do kernel
1159	  QA it is safe to say n.
1160
1161source "arch/x86/events/Kconfig"
1162
1163config X86_LEGACY_VM86
1164	bool "Legacy VM86 support"
1165	depends on X86_32
1166	help
1167	  This option allows user programs to put the CPU into V8086
1168	  mode, which is an 80286-era approximation of 16-bit real mode.
1169
1170	  Some very old versions of X and/or vbetool require this option
1171	  for user mode setting.  Similarly, DOSEMU will use it if
1172	  available to accelerate real mode DOS programs.  However, any
1173	  recent version of DOSEMU, X, or vbetool should be fully
1174	  functional even without kernel VM86 support, as they will all
1175	  fall back to software emulation. Nevertheless, if you are using
1176	  a 16-bit DOS program where 16-bit performance matters, vm86
1177	  mode might be faster than emulation and you might want to
1178	  enable this option.
1179
1180	  Note that any app that works on a 64-bit kernel is unlikely to
1181	  need this option, as 64-bit kernels don't, and can't, support
1182	  V8086 mode. This option is also unrelated to 16-bit protected
1183	  mode and is not needed to run most 16-bit programs under Wine.
1184
1185	  Enabling this option increases the complexity of the kernel
1186	  and slows down exception handling a tiny bit.
1187
1188	  If unsure, say N here.
1189
1190config VM86
1191	bool
1192	default X86_LEGACY_VM86
1193
1194config X86_16BIT
1195	bool "Enable support for 16-bit segments" if EXPERT
1196	default y
1197	depends on MODIFY_LDT_SYSCALL
1198	help
1199	  This option is required by programs like Wine to run 16-bit
1200	  protected mode legacy code on x86 processors.  Disabling
1201	  this option saves about 300 bytes on i386, or around 6K text
1202	  plus 16K runtime memory on x86-64,
1203
1204config X86_ESPFIX32
1205	def_bool y
1206	depends on X86_16BIT && X86_32
1207
1208config X86_ESPFIX64
1209	def_bool y
1210	depends on X86_16BIT && X86_64
1211
1212config X86_VSYSCALL_EMULATION
1213	bool "Enable vsyscall emulation" if EXPERT
1214	default y
1215	depends on X86_64
1216	help
1217	 This enables emulation of the legacy vsyscall page.  Disabling
1218	 it is roughly equivalent to booting with vsyscall=none, except
1219	 that it will also disable the helpful warning if a program
1220	 tries to use a vsyscall.  With this option set to N, offending
1221	 programs will just segfault, citing addresses of the form
1222	 0xffffffffff600?00.
1223
1224	 This option is required by many programs built before 2013, and
1225	 care should be used even with newer programs if set to N.
1226
1227	 Disabling this option saves about 7K of kernel size and
1228	 possibly 4K of additional runtime pagetable memory.
1229
1230config X86_IOPL_IOPERM
1231	bool "IOPERM and IOPL Emulation"
1232	default y
1233	help
1234	  This enables the ioperm() and iopl() syscalls which are necessary
1235	  for legacy applications.
1236
1237	  Legacy IOPL support is an overbroad mechanism which allows user
1238	  space aside of accessing all 65536 I/O ports also to disable
1239	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1240	  capabilities and permission from potentially active security
1241	  modules.
1242
1243	  The emulation restricts the functionality of the syscall to
1244	  only allowing the full range I/O port access, but prevents the
1245	  ability to disable interrupts from user space which would be
1246	  granted if the hardware IOPL mechanism would be used.
1247
1248config TOSHIBA
1249	tristate "Toshiba Laptop support"
1250	depends on X86_32
1251	help
1252	  This adds a driver to safely access the System Management Mode of
1253	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1254	  not work on models with a Phoenix BIOS. The System Management Mode
1255	  is used to set the BIOS and power saving options on Toshiba portables.
1256
1257	  For information on utilities to make use of this driver see the
1258	  Toshiba Linux utilities web site at:
1259	  <http://www.buzzard.org.uk/toshiba/>.
1260
1261	  Say Y if you intend to run this kernel on a Toshiba portable.
1262	  Say N otherwise.
1263
1264config I8K
1265	tristate "Dell i8k legacy laptop support"
1266	select HWMON
1267	select SENSORS_DELL_SMM
1268	help
1269	  This option enables legacy /proc/i8k userspace interface in hwmon
1270	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1271	  temperature and allows controlling fan speeds of Dell laptops via
1272	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1273	  it reports also power and hotkey status. For fan speed control is
1274	  needed userspace package i8kutils.
1275
1276	  Say Y if you intend to run this kernel on old Dell laptops or want to
1277	  use userspace package i8kutils.
1278	  Say N otherwise.
1279
1280config X86_REBOOTFIXUPS
1281	bool "Enable X86 board specific fixups for reboot"
1282	depends on X86_32
1283	help
1284	  This enables chipset and/or board specific fixups to be done
1285	  in order to get reboot to work correctly. This is only needed on
1286	  some combinations of hardware and BIOS. The symptom, for which
1287	  this config is intended, is when reboot ends with a stalled/hung
1288	  system.
1289
1290	  Currently, the only fixup is for the Geode machines using
1291	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1292
1293	  Say Y if you want to enable the fixup. Currently, it's safe to
1294	  enable this option even if you don't need it.
1295	  Say N otherwise.
1296
1297config MICROCODE
1298	bool "CPU microcode loading support"
1299	default y
1300	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1301	help
1302	  If you say Y here, you will be able to update the microcode on
1303	  Intel and AMD processors. The Intel support is for the IA32 family,
1304	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1305	  AMD support is for families 0x10 and later. You will obviously need
1306	  the actual microcode binary data itself which is not shipped with
1307	  the Linux kernel.
1308
1309	  The preferred method to load microcode from a detached initrd is described
1310	  in Documentation/x86/microcode.rst. For that you need to enable
1311	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1312	  initrd for microcode blobs.
1313
1314	  In addition, you can build the microcode into the kernel. For that you
1315	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1316	  config option.
1317
1318config MICROCODE_INTEL
1319	bool "Intel microcode loading support"
1320	depends on MICROCODE
1321	default MICROCODE
1322	help
1323	  This options enables microcode patch loading support for Intel
1324	  processors.
1325
1326	  For the current Intel microcode data package go to
1327	  <https://downloadcenter.intel.com> and search for
1328	  'Linux Processor Microcode Data File'.
1329
1330config MICROCODE_AMD
1331	bool "AMD microcode loading support"
1332	depends on MICROCODE
1333	help
1334	  If you select this option, microcode patch loading support for AMD
1335	  processors will be enabled.
1336
1337config MICROCODE_OLD_INTERFACE
1338	bool "Ancient loading interface (DEPRECATED)"
1339	default n
1340	depends on MICROCODE
1341	help
1342	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1343	  which was used by userspace tools like iucode_tool and microcode.ctl.
1344	  It is inadequate because it runs too late to be able to properly
1345	  load microcode on a machine and it needs special tools. Instead, you
1346	  should've switched to the early loading method with the initrd or
1347	  builtin microcode by now: Documentation/x86/microcode.rst
1348
1349config X86_MSR
1350	tristate "/dev/cpu/*/msr - Model-specific register support"
1351	help
1352	  This device gives privileged processes access to the x86
1353	  Model-Specific Registers (MSRs).  It is a character device with
1354	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1355	  MSR accesses are directed to a specific CPU on multi-processor
1356	  systems.
1357
1358config X86_CPUID
1359	tristate "/dev/cpu/*/cpuid - CPU information support"
1360	help
1361	  This device gives processes access to the x86 CPUID instruction to
1362	  be executed on a specific processor.  It is a character device
1363	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1364	  /dev/cpu/31/cpuid.
1365
1366choice
1367	prompt "High Memory Support"
1368	default HIGHMEM4G
1369	depends on X86_32
1370
1371config NOHIGHMEM
1372	bool "off"
1373	help
1374	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1375	  However, the address space of 32-bit x86 processors is only 4
1376	  Gigabytes large. That means that, if you have a large amount of
1377	  physical memory, not all of it can be "permanently mapped" by the
1378	  kernel. The physical memory that's not permanently mapped is called
1379	  "high memory".
1380
1381	  If you are compiling a kernel which will never run on a machine with
1382	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1383	  choice and suitable for most users). This will result in a "3GB/1GB"
1384	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1385	  space and the remaining part of the 4GB virtual memory space is used
1386	  by the kernel to permanently map as much physical memory as
1387	  possible.
1388
1389	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1390	  answer "4GB" here.
1391
1392	  If more than 4 Gigabytes is used then answer "64GB" here. This
1393	  selection turns Intel PAE (Physical Address Extension) mode on.
1394	  PAE implements 3-level paging on IA32 processors. PAE is fully
1395	  supported by Linux, PAE mode is implemented on all recent Intel
1396	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1397	  then the kernel will not boot on CPUs that don't support PAE!
1398
1399	  The actual amount of total physical memory will either be
1400	  auto detected or can be forced by using a kernel command line option
1401	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1402	  your boot loader (lilo or loadlin) about how to pass options to the
1403	  kernel at boot time.)
1404
1405	  If unsure, say "off".
1406
1407config HIGHMEM4G
1408	bool "4GB"
1409	help
1410	  Select this if you have a 32-bit processor and between 1 and 4
1411	  gigabytes of physical RAM.
1412
1413config HIGHMEM64G
1414	bool "64GB"
1415	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1416	select X86_PAE
1417	help
1418	  Select this if you have a 32-bit processor and more than 4
1419	  gigabytes of physical RAM.
1420
1421endchoice
1422
1423choice
1424	prompt "Memory split" if EXPERT
1425	default VMSPLIT_3G
1426	depends on X86_32
1427	help
1428	  Select the desired split between kernel and user memory.
1429
1430	  If the address range available to the kernel is less than the
1431	  physical memory installed, the remaining memory will be available
1432	  as "high memory". Accessing high memory is a little more costly
1433	  than low memory, as it needs to be mapped into the kernel first.
1434	  Note that increasing the kernel address space limits the range
1435	  available to user programs, making the address space there
1436	  tighter.  Selecting anything other than the default 3G/1G split
1437	  will also likely make your kernel incompatible with binary-only
1438	  kernel modules.
1439
1440	  If you are not absolutely sure what you are doing, leave this
1441	  option alone!
1442
1443	config VMSPLIT_3G
1444		bool "3G/1G user/kernel split"
1445	config VMSPLIT_3G_OPT
1446		depends on !X86_PAE
1447		bool "3G/1G user/kernel split (for full 1G low memory)"
1448	config VMSPLIT_2G
1449		bool "2G/2G user/kernel split"
1450	config VMSPLIT_2G_OPT
1451		depends on !X86_PAE
1452		bool "2G/2G user/kernel split (for full 2G low memory)"
1453	config VMSPLIT_1G
1454		bool "1G/3G user/kernel split"
1455endchoice
1456
1457config PAGE_OFFSET
1458	hex
1459	default 0xB0000000 if VMSPLIT_3G_OPT
1460	default 0x80000000 if VMSPLIT_2G
1461	default 0x78000000 if VMSPLIT_2G_OPT
1462	default 0x40000000 if VMSPLIT_1G
1463	default 0xC0000000
1464	depends on X86_32
1465
1466config HIGHMEM
1467	def_bool y
1468	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1469
1470config X86_PAE
1471	bool "PAE (Physical Address Extension) Support"
1472	depends on X86_32 && !HIGHMEM4G
1473	select PHYS_ADDR_T_64BIT
1474	select SWIOTLB
1475	help
1476	  PAE is required for NX support, and furthermore enables
1477	  larger swapspace support for non-overcommit purposes. It
1478	  has the cost of more pagetable lookup overhead, and also
1479	  consumes more pagetable space per process.
1480
1481config X86_5LEVEL
1482	bool "Enable 5-level page tables support"
1483	default y
1484	select DYNAMIC_MEMORY_LAYOUT
1485	select SPARSEMEM_VMEMMAP
1486	depends on X86_64
1487	help
1488	  5-level paging enables access to larger address space:
1489	  upto 128 PiB of virtual address space and 4 PiB of
1490	  physical address space.
1491
1492	  It will be supported by future Intel CPUs.
1493
1494	  A kernel with the option enabled can be booted on machines that
1495	  support 4- or 5-level paging.
1496
1497	  See Documentation/x86/x86_64/5level-paging.rst for more
1498	  information.
1499
1500	  Say N if unsure.
1501
1502config X86_DIRECT_GBPAGES
1503	def_bool y
1504	depends on X86_64
1505	help
1506	  Certain kernel features effectively disable kernel
1507	  linear 1 GB mappings (even if the CPU otherwise
1508	  supports them), so don't confuse the user by printing
1509	  that we have them enabled.
1510
1511config X86_CPA_STATISTICS
1512	bool "Enable statistic for Change Page Attribute"
1513	depends on DEBUG_FS
1514	help
1515	  Expose statistics about the Change Page Attribute mechanism, which
1516	  helps to determine the effectiveness of preserving large and huge
1517	  page mappings when mapping protections are changed.
1518
1519config AMD_MEM_ENCRYPT
1520	bool "AMD Secure Memory Encryption (SME) support"
1521	depends on X86_64 && CPU_SUP_AMD
1522	select DMA_COHERENT_POOL
1523	select DYNAMIC_PHYSICAL_MASK
1524	select ARCH_USE_MEMREMAP_PROT
1525	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1526	select INSTRUCTION_DECODER
1527	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
1528	help
1529	  Say yes to enable support for the encryption of system memory.
1530	  This requires an AMD processor that supports Secure Memory
1531	  Encryption (SME).
1532
1533config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1534	bool "Activate AMD Secure Memory Encryption (SME) by default"
1535	default y
1536	depends on AMD_MEM_ENCRYPT
1537	help
1538	  Say yes to have system memory encrypted by default if running on
1539	  an AMD processor that supports Secure Memory Encryption (SME).
1540
1541	  If set to Y, then the encryption of system memory can be
1542	  deactivated with the mem_encrypt=off command line option.
1543
1544	  If set to N, then the encryption of system memory can be
1545	  activated with the mem_encrypt=on command line option.
1546
1547# Common NUMA Features
1548config NUMA
1549	bool "NUMA Memory Allocation and Scheduler Support"
1550	depends on SMP
1551	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1552	default y if X86_BIGSMP
1553	help
1554	  Enable NUMA (Non-Uniform Memory Access) support.
1555
1556	  The kernel will try to allocate memory used by a CPU on the
1557	  local memory controller of the CPU and add some more
1558	  NUMA awareness to the kernel.
1559
1560	  For 64-bit this is recommended if the system is Intel Core i7
1561	  (or later), AMD Opteron, or EM64T NUMA.
1562
1563	  For 32-bit this is only needed if you boot a 32-bit
1564	  kernel on a 64-bit NUMA platform.
1565
1566	  Otherwise, you should say N.
1567
1568config AMD_NUMA
1569	def_bool y
1570	prompt "Old style AMD Opteron NUMA detection"
1571	depends on X86_64 && NUMA && PCI
1572	help
1573	  Enable AMD NUMA node topology detection.  You should say Y here if
1574	  you have a multi processor AMD system. This uses an old method to
1575	  read the NUMA configuration directly from the builtin Northbridge
1576	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1577	  which also takes priority if both are compiled in.
1578
1579config X86_64_ACPI_NUMA
1580	def_bool y
1581	prompt "ACPI NUMA detection"
1582	depends on X86_64 && NUMA && ACPI && PCI
1583	select ACPI_NUMA
1584	help
1585	  Enable ACPI SRAT based node topology detection.
1586
1587config NUMA_EMU
1588	bool "NUMA emulation"
1589	depends on NUMA
1590	help
1591	  Enable NUMA emulation. A flat machine will be split
1592	  into virtual nodes when booted with "numa=fake=N", where N is the
1593	  number of nodes. This is only useful for debugging.
1594
1595config NODES_SHIFT
1596	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1597	range 1 10
1598	default "10" if MAXSMP
1599	default "6" if X86_64
1600	default "3"
1601	depends on NEED_MULTIPLE_NODES
1602	help
1603	  Specify the maximum number of NUMA Nodes available on the target
1604	  system.  Increases memory reserved to accommodate various tables.
1605
1606config ARCH_FLATMEM_ENABLE
1607	def_bool y
1608	depends on X86_32 && !NUMA
1609
1610config ARCH_SPARSEMEM_ENABLE
1611	def_bool y
1612	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1613	select SPARSEMEM_STATIC if X86_32
1614	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1615
1616config ARCH_SPARSEMEM_DEFAULT
1617	def_bool X86_64 || (NUMA && X86_32)
1618
1619config ARCH_SELECT_MEMORY_MODEL
1620	def_bool y
1621	depends on ARCH_SPARSEMEM_ENABLE
1622
1623config ARCH_MEMORY_PROBE
1624	bool "Enable sysfs memory/probe interface"
1625	depends on X86_64 && MEMORY_HOTPLUG
1626	help
1627	  This option enables a sysfs memory/probe interface for testing.
1628	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1629	  If you are unsure how to answer this question, answer N.
1630
1631config ARCH_PROC_KCORE_TEXT
1632	def_bool y
1633	depends on X86_64 && PROC_KCORE
1634
1635config ILLEGAL_POINTER_VALUE
1636	hex
1637	default 0 if X86_32
1638	default 0xdead000000000000 if X86_64
1639
1640config X86_PMEM_LEGACY_DEVICE
1641	bool
1642
1643config X86_PMEM_LEGACY
1644	tristate "Support non-standard NVDIMMs and ADR protected memory"
1645	depends on PHYS_ADDR_T_64BIT
1646	depends on BLK_DEV
1647	select X86_PMEM_LEGACY_DEVICE
1648	select NUMA_KEEP_MEMINFO if NUMA
1649	select LIBNVDIMM
1650	help
1651	  Treat memory marked using the non-standard e820 type of 12 as used
1652	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1653	  The kernel will offer these regions to the 'pmem' driver so
1654	  they can be used for persistent storage.
1655
1656	  Say Y if unsure.
1657
1658config HIGHPTE
1659	bool "Allocate 3rd-level pagetables from highmem"
1660	depends on HIGHMEM
1661	help
1662	  The VM uses one page table entry for each page of physical memory.
1663	  For systems with a lot of RAM, this can be wasteful of precious
1664	  low memory.  Setting this option will put user-space page table
1665	  entries in high memory.
1666
1667config X86_CHECK_BIOS_CORRUPTION
1668	bool "Check for low memory corruption"
1669	help
1670	  Periodically check for memory corruption in low memory, which
1671	  is suspected to be caused by BIOS.  Even when enabled in the
1672	  configuration, it is disabled at runtime.  Enable it by
1673	  setting "memory_corruption_check=1" on the kernel command
1674	  line.  By default it scans the low 64k of memory every 60
1675	  seconds; see the memory_corruption_check_size and
1676	  memory_corruption_check_period parameters in
1677	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1678
1679	  When enabled with the default parameters, this option has
1680	  almost no overhead, as it reserves a relatively small amount
1681	  of memory and scans it infrequently.  It both detects corruption
1682	  and prevents it from affecting the running system.
1683
1684	  It is, however, intended as a diagnostic tool; if repeatable
1685	  BIOS-originated corruption always affects the same memory,
1686	  you can use memmap= to prevent the kernel from using that
1687	  memory.
1688
1689config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1690	bool "Set the default setting of memory_corruption_check"
1691	depends on X86_CHECK_BIOS_CORRUPTION
1692	default y
1693	help
1694	  Set whether the default state of memory_corruption_check is
1695	  on or off.
1696
1697config X86_RESERVE_LOW
1698	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1699	default 64
1700	range 4 640
1701	help
1702	  Specify the amount of low memory to reserve for the BIOS.
1703
1704	  The first page contains BIOS data structures that the kernel
1705	  must not use, so that page must always be reserved.
1706
1707	  By default we reserve the first 64K of physical RAM, as a
1708	  number of BIOSes are known to corrupt that memory range
1709	  during events such as suspend/resume or monitor cable
1710	  insertion, so it must not be used by the kernel.
1711
1712	  You can set this to 4 if you are absolutely sure that you
1713	  trust the BIOS to get all its memory reservations and usages
1714	  right.  If you know your BIOS have problems beyond the
1715	  default 64K area, you can set this to 640 to avoid using the
1716	  entire low memory range.
1717
1718	  If you have doubts about the BIOS (e.g. suspend/resume does
1719	  not work or there's kernel crashes after certain hardware
1720	  hotplug events) then you might want to enable
1721	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1722	  typical corruption patterns.
1723
1724	  Leave this to the default value of 64 if you are unsure.
1725
1726config MATH_EMULATION
1727	bool
1728	depends on MODIFY_LDT_SYSCALL
1729	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1730	help
1731	  Linux can emulate a math coprocessor (used for floating point
1732	  operations) if you don't have one. 486DX and Pentium processors have
1733	  a math coprocessor built in, 486SX and 386 do not, unless you added
1734	  a 487DX or 387, respectively. (The messages during boot time can
1735	  give you some hints here ["man dmesg"].) Everyone needs either a
1736	  coprocessor or this emulation.
1737
1738	  If you don't have a math coprocessor, you need to say Y here; if you
1739	  say Y here even though you have a coprocessor, the coprocessor will
1740	  be used nevertheless. (This behavior can be changed with the kernel
1741	  command line option "no387", which comes handy if your coprocessor
1742	  is broken. Try "man bootparam" or see the documentation of your boot
1743	  loader (lilo or loadlin) about how to pass options to the kernel at
1744	  boot time.) This means that it is a good idea to say Y here if you
1745	  intend to use this kernel on different machines.
1746
1747	  More information about the internals of the Linux math coprocessor
1748	  emulation can be found in <file:arch/x86/math-emu/README>.
1749
1750	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1751	  kernel, it won't hurt.
1752
1753config MTRR
1754	def_bool y
1755	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1756	help
1757	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1758	  the Memory Type Range Registers (MTRRs) may be used to control
1759	  processor access to memory ranges. This is most useful if you have
1760	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1761	  allows bus write transfers to be combined into a larger transfer
1762	  before bursting over the PCI/AGP bus. This can increase performance
1763	  of image write operations 2.5 times or more. Saying Y here creates a
1764	  /proc/mtrr file which may be used to manipulate your processor's
1765	  MTRRs. Typically the X server should use this.
1766
1767	  This code has a reasonably generic interface so that similar
1768	  control registers on other processors can be easily supported
1769	  as well:
1770
1771	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1772	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1773	  these, the ARRs are used to emulate the MTRRs.
1774	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1775	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1776	  write-combining. All of these processors are supported by this code
1777	  and it makes sense to say Y here if you have one of them.
1778
1779	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1780	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1781	  can lead to all sorts of problems, so it's good to say Y here.
1782
1783	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1784	  just add about 9 KB to your kernel.
1785
1786	  See <file:Documentation/x86/mtrr.rst> for more information.
1787
1788config MTRR_SANITIZER
1789	def_bool y
1790	prompt "MTRR cleanup support"
1791	depends on MTRR
1792	help
1793	  Convert MTRR layout from continuous to discrete, so X drivers can
1794	  add writeback entries.
1795
1796	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1797	  The largest mtrr entry size for a continuous block can be set with
1798	  mtrr_chunk_size.
1799
1800	  If unsure, say Y.
1801
1802config MTRR_SANITIZER_ENABLE_DEFAULT
1803	int "MTRR cleanup enable value (0-1)"
1804	range 0 1
1805	default "0"
1806	depends on MTRR_SANITIZER
1807	help
1808	  Enable mtrr cleanup default value
1809
1810config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1811	int "MTRR cleanup spare reg num (0-7)"
1812	range 0 7
1813	default "1"
1814	depends on MTRR_SANITIZER
1815	help
1816	  mtrr cleanup spare entries default, it can be changed via
1817	  mtrr_spare_reg_nr=N on the kernel command line.
1818
1819config X86_PAT
1820	def_bool y
1821	prompt "x86 PAT support" if EXPERT
1822	depends on MTRR
1823	help
1824	  Use PAT attributes to setup page level cache control.
1825
1826	  PATs are the modern equivalents of MTRRs and are much more
1827	  flexible than MTRRs.
1828
1829	  Say N here if you see bootup problems (boot crash, boot hang,
1830	  spontaneous reboots) or a non-working video driver.
1831
1832	  If unsure, say Y.
1833
1834config ARCH_USES_PG_UNCACHED
1835	def_bool y
1836	depends on X86_PAT
1837
1838config ARCH_RANDOM
1839	def_bool y
1840	prompt "x86 architectural random number generator" if EXPERT
1841	help
1842	  Enable the x86 architectural RDRAND instruction
1843	  (Intel Bull Mountain technology) to generate random numbers.
1844	  If supported, this is a high bandwidth, cryptographically
1845	  secure hardware random number generator.
1846
1847config X86_SMAP
1848	def_bool y
1849	prompt "Supervisor Mode Access Prevention" if EXPERT
1850	help
1851	  Supervisor Mode Access Prevention (SMAP) is a security
1852	  feature in newer Intel processors.  There is a small
1853	  performance cost if this enabled and turned on; there is
1854	  also a small increase in the kernel size if this is enabled.
1855
1856	  If unsure, say Y.
1857
1858config X86_UMIP
1859	def_bool y
1860	prompt "User Mode Instruction Prevention" if EXPERT
1861	help
1862	  User Mode Instruction Prevention (UMIP) is a security feature in
1863	  some x86 processors. If enabled, a general protection fault is
1864	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1865	  executed in user mode. These instructions unnecessarily expose
1866	  information about the hardware state.
1867
1868	  The vast majority of applications do not use these instructions.
1869	  For the very few that do, software emulation is provided in
1870	  specific cases in protected and virtual-8086 modes. Emulated
1871	  results are dummy.
1872
1873config X86_INTEL_MEMORY_PROTECTION_KEYS
1874	prompt "Memory Protection Keys"
1875	def_bool y
1876	# Note: only available in 64-bit mode
1877	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1878	select ARCH_USES_HIGH_VMA_FLAGS
1879	select ARCH_HAS_PKEYS
1880	help
1881	  Memory Protection Keys provides a mechanism for enforcing
1882	  page-based protections, but without requiring modification of the
1883	  page tables when an application changes protection domains.
1884
1885	  For details, see Documentation/core-api/protection-keys.rst
1886
1887	  If unsure, say y.
1888
1889choice
1890	prompt "TSX enable mode"
1891	depends on CPU_SUP_INTEL
1892	default X86_INTEL_TSX_MODE_OFF
1893	help
1894	  Intel's TSX (Transactional Synchronization Extensions) feature
1895	  allows to optimize locking protocols through lock elision which
1896	  can lead to a noticeable performance boost.
1897
1898	  On the other hand it has been shown that TSX can be exploited
1899	  to form side channel attacks (e.g. TAA) and chances are there
1900	  will be more of those attacks discovered in the future.
1901
1902	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1903	  might override this decision by tsx=on the command line parameter.
1904	  Even with TSX enabled, the kernel will attempt to enable the best
1905	  possible TAA mitigation setting depending on the microcode available
1906	  for the particular machine.
1907
1908	  This option allows to set the default tsx mode between tsx=on, =off
1909	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1910	  details.
1911
1912	  Say off if not sure, auto if TSX is in use but it should be used on safe
1913	  platforms or on if TSX is in use and the security aspect of tsx is not
1914	  relevant.
1915
1916config X86_INTEL_TSX_MODE_OFF
1917	bool "off"
1918	help
1919	  TSX is disabled if possible - equals to tsx=off command line parameter.
1920
1921config X86_INTEL_TSX_MODE_ON
1922	bool "on"
1923	help
1924	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1925	  line parameter.
1926
1927config X86_INTEL_TSX_MODE_AUTO
1928	bool "auto"
1929	help
1930	  TSX is enabled on TSX capable HW that is believed to be safe against
1931	  side channel attacks- equals the tsx=auto command line parameter.
1932endchoice
1933
1934config X86_SGX
1935	bool "Software Guard eXtensions (SGX)"
1936	depends on X86_64 && CPU_SUP_INTEL
1937	depends on CRYPTO=y
1938	depends on CRYPTO_SHA256=y
1939	select SRCU
1940	select MMU_NOTIFIER
1941	select NUMA_KEEP_MEMINFO if NUMA
1942	help
1943	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1944	  that can be used by applications to set aside private regions of code
1945	  and data, referred to as enclaves. An enclave's private memory can
1946	  only be accessed by code running within the enclave. Accesses from
1947	  outside the enclave, including other enclaves, are disallowed by
1948	  hardware.
1949
1950	  If unsure, say N.
1951
1952config EFI
1953	bool "EFI runtime service support"
1954	depends on ACPI
1955	select UCS2_STRING
1956	select EFI_RUNTIME_WRAPPERS
1957	help
1958	  This enables the kernel to use EFI runtime services that are
1959	  available (such as the EFI variable services).
1960
1961	  This option is only useful on systems that have EFI firmware.
1962	  In addition, you should use the latest ELILO loader available
1963	  at <http://elilo.sourceforge.net> in order to take advantage
1964	  of EFI runtime services. However, even with this option, the
1965	  resultant kernel should continue to boot on existing non-EFI
1966	  platforms.
1967
1968config EFI_STUB
1969	bool "EFI stub support"
1970	depends on EFI && !X86_USE_3DNOW
1971	depends on $(cc-option,-mabi=ms) || X86_32
1972	select RELOCATABLE
1973	help
1974	  This kernel feature allows a bzImage to be loaded directly
1975	  by EFI firmware without the use of a bootloader.
1976
1977	  See Documentation/admin-guide/efi-stub.rst for more information.
1978
1979config EFI_MIXED
1980	bool "EFI mixed-mode support"
1981	depends on EFI_STUB && X86_64
1982	help
1983	   Enabling this feature allows a 64-bit kernel to be booted
1984	   on a 32-bit firmware, provided that your CPU supports 64-bit
1985	   mode.
1986
1987	   Note that it is not possible to boot a mixed-mode enabled
1988	   kernel via the EFI boot stub - a bootloader that supports
1989	   the EFI handover protocol must be used.
1990
1991	   If unsure, say N.
1992
1993source "kernel/Kconfig.hz"
1994
1995config KEXEC
1996	bool "kexec system call"
1997	select KEXEC_CORE
1998	help
1999	  kexec is a system call that implements the ability to shutdown your
2000	  current kernel, and to start another kernel.  It is like a reboot
2001	  but it is independent of the system firmware.   And like a reboot
2002	  you can start any kernel with it, not just Linux.
2003
2004	  The name comes from the similarity to the exec system call.
2005
2006	  It is an ongoing process to be certain the hardware in a machine
2007	  is properly shutdown, so do not be surprised if this code does not
2008	  initially work for you.  As of this writing the exact hardware
2009	  interface is strongly in flux, so no good recommendation can be
2010	  made.
2011
2012config KEXEC_FILE
2013	bool "kexec file based system call"
2014	select KEXEC_CORE
2015	select BUILD_BIN2C
2016	depends on X86_64
2017	depends on CRYPTO=y
2018	depends on CRYPTO_SHA256=y
2019	help
2020	  This is new version of kexec system call. This system call is
2021	  file based and takes file descriptors as system call argument
2022	  for kernel and initramfs as opposed to list of segments as
2023	  accepted by previous system call.
2024
2025config ARCH_HAS_KEXEC_PURGATORY
2026	def_bool KEXEC_FILE
2027
2028config KEXEC_SIG
2029	bool "Verify kernel signature during kexec_file_load() syscall"
2030	depends on KEXEC_FILE
2031	help
2032
2033	  This option makes the kexec_file_load() syscall check for a valid
2034	  signature of the kernel image.  The image can still be loaded without
2035	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2036	  there's a signature that we can check, then it must be valid.
2037
2038	  In addition to this option, you need to enable signature
2039	  verification for the corresponding kernel image type being
2040	  loaded in order for this to work.
2041
2042config KEXEC_SIG_FORCE
2043	bool "Require a valid signature in kexec_file_load() syscall"
2044	depends on KEXEC_SIG
2045	help
2046	  This option makes kernel signature verification mandatory for
2047	  the kexec_file_load() syscall.
2048
2049config KEXEC_BZIMAGE_VERIFY_SIG
2050	bool "Enable bzImage signature verification support"
2051	depends on KEXEC_SIG
2052	depends on SIGNED_PE_FILE_VERIFICATION
2053	select SYSTEM_TRUSTED_KEYRING
2054	help
2055	  Enable bzImage signature verification support.
2056
2057config CRASH_DUMP
2058	bool "kernel crash dumps"
2059	depends on X86_64 || (X86_32 && HIGHMEM)
2060	help
2061	  Generate crash dump after being started by kexec.
2062	  This should be normally only set in special crash dump kernels
2063	  which are loaded in the main kernel with kexec-tools into
2064	  a specially reserved region and then later executed after
2065	  a crash by kdump/kexec. The crash dump kernel must be compiled
2066	  to a memory address not used by the main kernel or BIOS using
2067	  PHYSICAL_START, or it must be built as a relocatable image
2068	  (CONFIG_RELOCATABLE=y).
2069	  For more details see Documentation/admin-guide/kdump/kdump.rst
2070
2071config KEXEC_JUMP
2072	bool "kexec jump"
2073	depends on KEXEC && HIBERNATION
2074	help
2075	  Jump between original kernel and kexeced kernel and invoke
2076	  code in physical address mode via KEXEC
2077
2078config PHYSICAL_START
2079	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2080	default "0x1000000"
2081	help
2082	  This gives the physical address where the kernel is loaded.
2083
2084	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2085	  bzImage will decompress itself to above physical address and
2086	  run from there. Otherwise, bzImage will run from the address where
2087	  it has been loaded by the boot loader and will ignore above physical
2088	  address.
2089
2090	  In normal kdump cases one does not have to set/change this option
2091	  as now bzImage can be compiled as a completely relocatable image
2092	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2093	  address. This option is mainly useful for the folks who don't want
2094	  to use a bzImage for capturing the crash dump and want to use a
2095	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2096	  to be specifically compiled to run from a specific memory area
2097	  (normally a reserved region) and this option comes handy.
2098
2099	  So if you are using bzImage for capturing the crash dump,
2100	  leave the value here unchanged to 0x1000000 and set
2101	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2102	  for capturing the crash dump change this value to start of
2103	  the reserved region.  In other words, it can be set based on
2104	  the "X" value as specified in the "crashkernel=YM@XM"
2105	  command line boot parameter passed to the panic-ed
2106	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2107	  for more details about crash dumps.
2108
2109	  Usage of bzImage for capturing the crash dump is recommended as
2110	  one does not have to build two kernels. Same kernel can be used
2111	  as production kernel and capture kernel. Above option should have
2112	  gone away after relocatable bzImage support is introduced. But it
2113	  is present because there are users out there who continue to use
2114	  vmlinux for dump capture. This option should go away down the
2115	  line.
2116
2117	  Don't change this unless you know what you are doing.
2118
2119config RELOCATABLE
2120	bool "Build a relocatable kernel"
2121	default y
2122	help
2123	  This builds a kernel image that retains relocation information
2124	  so it can be loaded someplace besides the default 1MB.
2125	  The relocations tend to make the kernel binary about 10% larger,
2126	  but are discarded at runtime.
2127
2128	  One use is for the kexec on panic case where the recovery kernel
2129	  must live at a different physical address than the primary
2130	  kernel.
2131
2132	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2133	  it has been loaded at and the compile time physical address
2134	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2135
2136config RANDOMIZE_BASE
2137	bool "Randomize the address of the kernel image (KASLR)"
2138	depends on RELOCATABLE
2139	default y
2140	help
2141	  In support of Kernel Address Space Layout Randomization (KASLR),
2142	  this randomizes the physical address at which the kernel image
2143	  is decompressed and the virtual address where the kernel
2144	  image is mapped, as a security feature that deters exploit
2145	  attempts relying on knowledge of the location of kernel
2146	  code internals.
2147
2148	  On 64-bit, the kernel physical and virtual addresses are
2149	  randomized separately. The physical address will be anywhere
2150	  between 16MB and the top of physical memory (up to 64TB). The
2151	  virtual address will be randomized from 16MB up to 1GB (9 bits
2152	  of entropy). Note that this also reduces the memory space
2153	  available to kernel modules from 1.5GB to 1GB.
2154
2155	  On 32-bit, the kernel physical and virtual addresses are
2156	  randomized together. They will be randomized from 16MB up to
2157	  512MB (8 bits of entropy).
2158
2159	  Entropy is generated using the RDRAND instruction if it is
2160	  supported. If RDTSC is supported, its value is mixed into
2161	  the entropy pool as well. If neither RDRAND nor RDTSC are
2162	  supported, then entropy is read from the i8254 timer. The
2163	  usable entropy is limited by the kernel being built using
2164	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2165	  minimum of 2MB. As a result, only 10 bits of entropy are
2166	  theoretically possible, but the implementations are further
2167	  limited due to memory layouts.
2168
2169	  If unsure, say Y.
2170
2171# Relocation on x86 needs some additional build support
2172config X86_NEED_RELOCS
2173	def_bool y
2174	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2175
2176config PHYSICAL_ALIGN
2177	hex "Alignment value to which kernel should be aligned"
2178	default "0x200000"
2179	range 0x2000 0x1000000 if X86_32
2180	range 0x200000 0x1000000 if X86_64
2181	help
2182	  This value puts the alignment restrictions on physical address
2183	  where kernel is loaded and run from. Kernel is compiled for an
2184	  address which meets above alignment restriction.
2185
2186	  If bootloader loads the kernel at a non-aligned address and
2187	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2188	  address aligned to above value and run from there.
2189
2190	  If bootloader loads the kernel at a non-aligned address and
2191	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2192	  load address and decompress itself to the address it has been
2193	  compiled for and run from there. The address for which kernel is
2194	  compiled already meets above alignment restrictions. Hence the
2195	  end result is that kernel runs from a physical address meeting
2196	  above alignment restrictions.
2197
2198	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2199	  this value must be a multiple of 0x200000.
2200
2201	  Don't change this unless you know what you are doing.
2202
2203config DYNAMIC_MEMORY_LAYOUT
2204	bool
2205	help
2206	  This option makes base addresses of vmalloc and vmemmap as well as
2207	  __PAGE_OFFSET movable during boot.
2208
2209config RANDOMIZE_MEMORY
2210	bool "Randomize the kernel memory sections"
2211	depends on X86_64
2212	depends on RANDOMIZE_BASE
2213	select DYNAMIC_MEMORY_LAYOUT
2214	default RANDOMIZE_BASE
2215	help
2216	   Randomizes the base virtual address of kernel memory sections
2217	   (physical memory mapping, vmalloc & vmemmap). This security feature
2218	   makes exploits relying on predictable memory locations less reliable.
2219
2220	   The order of allocations remains unchanged. Entropy is generated in
2221	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2222	   configuration have in average 30,000 different possible virtual
2223	   addresses for each memory section.
2224
2225	   If unsure, say Y.
2226
2227config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2228	hex "Physical memory mapping padding" if EXPERT
2229	depends on RANDOMIZE_MEMORY
2230	default "0xa" if MEMORY_HOTPLUG
2231	default "0x0"
2232	range 0x1 0x40 if MEMORY_HOTPLUG
2233	range 0x0 0x40
2234	help
2235	   Define the padding in terabytes added to the existing physical
2236	   memory size during kernel memory randomization. It is useful
2237	   for memory hotplug support but reduces the entropy available for
2238	   address randomization.
2239
2240	   If unsure, leave at the default value.
2241
2242config HOTPLUG_CPU
2243	def_bool y
2244	depends on SMP
2245
2246config BOOTPARAM_HOTPLUG_CPU0
2247	bool "Set default setting of cpu0_hotpluggable"
2248	depends on HOTPLUG_CPU
2249	help
2250	  Set whether default state of cpu0_hotpluggable is on or off.
2251
2252	  Say Y here to enable CPU0 hotplug by default. If this switch
2253	  is turned on, there is no need to give cpu0_hotplug kernel
2254	  parameter and the CPU0 hotplug feature is enabled by default.
2255
2256	  Please note: there are two known CPU0 dependencies if you want
2257	  to enable the CPU0 hotplug feature either by this switch or by
2258	  cpu0_hotplug kernel parameter.
2259
2260	  First, resume from hibernate or suspend always starts from CPU0.
2261	  So hibernate and suspend are prevented if CPU0 is offline.
2262
2263	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2264	  offline if any interrupt can not migrate out of CPU0. There may
2265	  be other CPU0 dependencies.
2266
2267	  Please make sure the dependencies are under your control before
2268	  you enable this feature.
2269
2270	  Say N if you don't want to enable CPU0 hotplug feature by default.
2271	  You still can enable the CPU0 hotplug feature at boot by kernel
2272	  parameter cpu0_hotplug.
2273
2274config DEBUG_HOTPLUG_CPU0
2275	def_bool n
2276	prompt "Debug CPU0 hotplug"
2277	depends on HOTPLUG_CPU
2278	help
2279	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2280	  soon as possible and boots up userspace with CPU0 offlined. User
2281	  can online CPU0 back after boot time.
2282
2283	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2284	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2285	  compilation or giving cpu0_hotplug kernel parameter at boot.
2286
2287	  If unsure, say N.
2288
2289config COMPAT_VDSO
2290	def_bool n
2291	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2292	depends on COMPAT_32
2293	help
2294	  Certain buggy versions of glibc will crash if they are
2295	  presented with a 32-bit vDSO that is not mapped at the address
2296	  indicated in its segment table.
2297
2298	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2299	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2300	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2301	  the only released version with the bug, but OpenSUSE 9
2302	  contains a buggy "glibc 2.3.2".
2303
2304	  The symptom of the bug is that everything crashes on startup, saying:
2305	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2306
2307	  Saying Y here changes the default value of the vdso32 boot
2308	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2309	  This works around the glibc bug but hurts performance.
2310
2311	  If unsure, say N: if you are compiling your own kernel, you
2312	  are unlikely to be using a buggy version of glibc.
2313
2314choice
2315	prompt "vsyscall table for legacy applications"
2316	depends on X86_64
2317	default LEGACY_VSYSCALL_XONLY
2318	help
2319	  Legacy user code that does not know how to find the vDSO expects
2320	  to be able to issue three syscalls by calling fixed addresses in
2321	  kernel space. Since this location is not randomized with ASLR,
2322	  it can be used to assist security vulnerability exploitation.
2323
2324	  This setting can be changed at boot time via the kernel command
2325	  line parameter vsyscall=[emulate|xonly|none].
2326
2327	  On a system with recent enough glibc (2.14 or newer) and no
2328	  static binaries, you can say None without a performance penalty
2329	  to improve security.
2330
2331	  If unsure, select "Emulate execution only".
2332
2333	config LEGACY_VSYSCALL_EMULATE
2334		bool "Full emulation"
2335		help
2336		  The kernel traps and emulates calls into the fixed vsyscall
2337		  address mapping. This makes the mapping non-executable, but
2338		  it still contains readable known contents, which could be
2339		  used in certain rare security vulnerability exploits. This
2340		  configuration is recommended when using legacy userspace
2341		  that still uses vsyscalls along with legacy binary
2342		  instrumentation tools that require code to be readable.
2343
2344		  An example of this type of legacy userspace is running
2345		  Pin on an old binary that still uses vsyscalls.
2346
2347	config LEGACY_VSYSCALL_XONLY
2348		bool "Emulate execution only"
2349		help
2350		  The kernel traps and emulates calls into the fixed vsyscall
2351		  address mapping and does not allow reads.  This
2352		  configuration is recommended when userspace might use the
2353		  legacy vsyscall area but support for legacy binary
2354		  instrumentation of legacy code is not needed.  It mitigates
2355		  certain uses of the vsyscall area as an ASLR-bypassing
2356		  buffer.
2357
2358	config LEGACY_VSYSCALL_NONE
2359		bool "None"
2360		help
2361		  There will be no vsyscall mapping at all. This will
2362		  eliminate any risk of ASLR bypass due to the vsyscall
2363		  fixed address mapping. Attempts to use the vsyscalls
2364		  will be reported to dmesg, so that either old or
2365		  malicious userspace programs can be identified.
2366
2367endchoice
2368
2369config CMDLINE_BOOL
2370	bool "Built-in kernel command line"
2371	help
2372	  Allow for specifying boot arguments to the kernel at
2373	  build time.  On some systems (e.g. embedded ones), it is
2374	  necessary or convenient to provide some or all of the
2375	  kernel boot arguments with the kernel itself (that is,
2376	  to not rely on the boot loader to provide them.)
2377
2378	  To compile command line arguments into the kernel,
2379	  set this option to 'Y', then fill in the
2380	  boot arguments in CONFIG_CMDLINE.
2381
2382	  Systems with fully functional boot loaders (i.e. non-embedded)
2383	  should leave this option set to 'N'.
2384
2385config CMDLINE
2386	string "Built-in kernel command string"
2387	depends on CMDLINE_BOOL
2388	default ""
2389	help
2390	  Enter arguments here that should be compiled into the kernel
2391	  image and used at boot time.  If the boot loader provides a
2392	  command line at boot time, it is appended to this string to
2393	  form the full kernel command line, when the system boots.
2394
2395	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2396	  change this behavior.
2397
2398	  In most cases, the command line (whether built-in or provided
2399	  by the boot loader) should specify the device for the root
2400	  file system.
2401
2402config CMDLINE_OVERRIDE
2403	bool "Built-in command line overrides boot loader arguments"
2404	depends on CMDLINE_BOOL && CMDLINE != ""
2405	help
2406	  Set this option to 'Y' to have the kernel ignore the boot loader
2407	  command line, and use ONLY the built-in command line.
2408
2409	  This is used to work around broken boot loaders.  This should
2410	  be set to 'N' under normal conditions.
2411
2412config MODIFY_LDT_SYSCALL
2413	bool "Enable the LDT (local descriptor table)" if EXPERT
2414	default y
2415	help
2416	  Linux can allow user programs to install a per-process x86
2417	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2418	  call.  This is required to run 16-bit or segmented code such as
2419	  DOSEMU or some Wine programs.  It is also used by some very old
2420	  threading libraries.
2421
2422	  Enabling this feature adds a small amount of overhead to
2423	  context switches and increases the low-level kernel attack
2424	  surface.  Disabling it removes the modify_ldt(2) system call.
2425
2426	  Saying 'N' here may make sense for embedded or server kernels.
2427
2428source "kernel/livepatch/Kconfig"
2429
2430endmenu
2431
2432config ARCH_HAS_ADD_PAGES
2433	def_bool y
2434	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2435
2436config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2437	def_bool y
2438
2439config USE_PERCPU_NUMA_NODE_ID
2440	def_bool y
2441	depends on NUMA
2442
2443menu "Power management and ACPI options"
2444
2445config ARCH_HIBERNATION_HEADER
2446	def_bool y
2447	depends on HIBERNATION
2448
2449source "kernel/power/Kconfig"
2450
2451source "drivers/acpi/Kconfig"
2452
2453config X86_APM_BOOT
2454	def_bool y
2455	depends on APM
2456
2457menuconfig APM
2458	tristate "APM (Advanced Power Management) BIOS support"
2459	depends on X86_32 && PM_SLEEP
2460	help
2461	  APM is a BIOS specification for saving power using several different
2462	  techniques. This is mostly useful for battery powered laptops with
2463	  APM compliant BIOSes. If you say Y here, the system time will be
2464	  reset after a RESUME operation, the /proc/apm device will provide
2465	  battery status information, and user-space programs will receive
2466	  notification of APM "events" (e.g. battery status change).
2467
2468	  If you select "Y" here, you can disable actual use of the APM
2469	  BIOS by passing the "apm=off" option to the kernel at boot time.
2470
2471	  Note that the APM support is almost completely disabled for
2472	  machines with more than one CPU.
2473
2474	  In order to use APM, you will need supporting software. For location
2475	  and more information, read <file:Documentation/power/apm-acpi.rst>
2476	  and the Battery Powered Linux mini-HOWTO, available from
2477	  <http://www.tldp.org/docs.html#howto>.
2478
2479	  This driver does not spin down disk drives (see the hdparm(8)
2480	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2481	  VESA-compliant "green" monitors.
2482
2483	  This driver does not support the TI 4000M TravelMate and the ACER
2484	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2485	  desktop machines also don't have compliant BIOSes, and this driver
2486	  may cause those machines to panic during the boot phase.
2487
2488	  Generally, if you don't have a battery in your machine, there isn't
2489	  much point in using this driver and you should say N. If you get
2490	  random kernel OOPSes or reboots that don't seem to be related to
2491	  anything, try disabling/enabling this option (or disabling/enabling
2492	  APM in your BIOS).
2493
2494	  Some other things you should try when experiencing seemingly random,
2495	  "weird" problems:
2496
2497	  1) make sure that you have enough swap space and that it is
2498	  enabled.
2499	  2) pass the "no-hlt" option to the kernel
2500	  3) switch on floating point emulation in the kernel and pass
2501	  the "no387" option to the kernel
2502	  4) pass the "floppy=nodma" option to the kernel
2503	  5) pass the "mem=4M" option to the kernel (thereby disabling
2504	  all but the first 4 MB of RAM)
2505	  6) make sure that the CPU is not over clocked.
2506	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2507	  8) disable the cache from your BIOS settings
2508	  9) install a fan for the video card or exchange video RAM
2509	  10) install a better fan for the CPU
2510	  11) exchange RAM chips
2511	  12) exchange the motherboard.
2512
2513	  To compile this driver as a module, choose M here: the
2514	  module will be called apm.
2515
2516if APM
2517
2518config APM_IGNORE_USER_SUSPEND
2519	bool "Ignore USER SUSPEND"
2520	help
2521	  This option will ignore USER SUSPEND requests. On machines with a
2522	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2523	  series notebooks, it is necessary to say Y because of a BIOS bug.
2524
2525config APM_DO_ENABLE
2526	bool "Enable PM at boot time"
2527	help
2528	  Enable APM features at boot time. From page 36 of the APM BIOS
2529	  specification: "When disabled, the APM BIOS does not automatically
2530	  power manage devices, enter the Standby State, enter the Suspend
2531	  State, or take power saving steps in response to CPU Idle calls."
2532	  This driver will make CPU Idle calls when Linux is idle (unless this
2533	  feature is turned off -- see "Do CPU IDLE calls", below). This
2534	  should always save battery power, but more complicated APM features
2535	  will be dependent on your BIOS implementation. You may need to turn
2536	  this option off if your computer hangs at boot time when using APM
2537	  support, or if it beeps continuously instead of suspending. Turn
2538	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2539	  T400CDT. This is off by default since most machines do fine without
2540	  this feature.
2541
2542config APM_CPU_IDLE
2543	depends on CPU_IDLE
2544	bool "Make CPU Idle calls when idle"
2545	help
2546	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2547	  On some machines, this can activate improved power savings, such as
2548	  a slowed CPU clock rate, when the machine is idle. These idle calls
2549	  are made after the idle loop has run for some length of time (e.g.,
2550	  333 mS). On some machines, this will cause a hang at boot time or
2551	  whenever the CPU becomes idle. (On machines with more than one CPU,
2552	  this option does nothing.)
2553
2554config APM_DISPLAY_BLANK
2555	bool "Enable console blanking using APM"
2556	help
2557	  Enable console blanking using the APM. Some laptops can use this to
2558	  turn off the LCD backlight when the screen blanker of the Linux
2559	  virtual console blanks the screen. Note that this is only used by
2560	  the virtual console screen blanker, and won't turn off the backlight
2561	  when using the X Window system. This also doesn't have anything to
2562	  do with your VESA-compliant power-saving monitor. Further, this
2563	  option doesn't work for all laptops -- it might not turn off your
2564	  backlight at all, or it might print a lot of errors to the console,
2565	  especially if you are using gpm.
2566
2567config APM_ALLOW_INTS
2568	bool "Allow interrupts during APM BIOS calls"
2569	help
2570	  Normally we disable external interrupts while we are making calls to
2571	  the APM BIOS as a measure to lessen the effects of a badly behaving
2572	  BIOS implementation.  The BIOS should reenable interrupts if it
2573	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2574	  many of the newer IBM Thinkpads.  If you experience hangs when you
2575	  suspend, try setting this to Y.  Otherwise, say N.
2576
2577endif # APM
2578
2579source "drivers/cpufreq/Kconfig"
2580
2581source "drivers/cpuidle/Kconfig"
2582
2583source "drivers/idle/Kconfig"
2584
2585endmenu
2586
2587
2588menu "Bus options (PCI etc.)"
2589
2590choice
2591	prompt "PCI access mode"
2592	depends on X86_32 && PCI
2593	default PCI_GOANY
2594	help
2595	  On PCI systems, the BIOS can be used to detect the PCI devices and
2596	  determine their configuration. However, some old PCI motherboards
2597	  have BIOS bugs and may crash if this is done. Also, some embedded
2598	  PCI-based systems don't have any BIOS at all. Linux can also try to
2599	  detect the PCI hardware directly without using the BIOS.
2600
2601	  With this option, you can specify how Linux should detect the
2602	  PCI devices. If you choose "BIOS", the BIOS will be used,
2603	  if you choose "Direct", the BIOS won't be used, and if you
2604	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2605	  If you choose "Any", the kernel will try MMCONFIG, then the
2606	  direct access method and falls back to the BIOS if that doesn't
2607	  work. If unsure, go with the default, which is "Any".
2608
2609config PCI_GOBIOS
2610	bool "BIOS"
2611
2612config PCI_GOMMCONFIG
2613	bool "MMConfig"
2614
2615config PCI_GODIRECT
2616	bool "Direct"
2617
2618config PCI_GOOLPC
2619	bool "OLPC XO-1"
2620	depends on OLPC
2621
2622config PCI_GOANY
2623	bool "Any"
2624
2625endchoice
2626
2627config PCI_BIOS
2628	def_bool y
2629	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2630
2631# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2632config PCI_DIRECT
2633	def_bool y
2634	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2635
2636config PCI_MMCONFIG
2637	bool "Support mmconfig PCI config space access" if X86_64
2638	default y
2639	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2640	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2641
2642config PCI_OLPC
2643	def_bool y
2644	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2645
2646config PCI_XEN
2647	def_bool y
2648	depends on PCI && XEN
2649	select SWIOTLB_XEN
2650
2651config MMCONF_FAM10H
2652	def_bool y
2653	depends on X86_64 && PCI_MMCONFIG && ACPI
2654
2655config PCI_CNB20LE_QUIRK
2656	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2657	depends on PCI
2658	help
2659	  Read the PCI windows out of the CNB20LE host bridge. This allows
2660	  PCI hotplug to work on systems with the CNB20LE chipset which do
2661	  not have ACPI.
2662
2663	  There's no public spec for this chipset, and this functionality
2664	  is known to be incomplete.
2665
2666	  You should say N unless you know you need this.
2667
2668config ISA_BUS
2669	bool "ISA bus support on modern systems" if EXPERT
2670	help
2671	  Expose ISA bus device drivers and options available for selection and
2672	  configuration. Enable this option if your target machine has an ISA
2673	  bus. ISA is an older system, displaced by PCI and newer bus
2674	  architectures -- if your target machine is modern, it probably does
2675	  not have an ISA bus.
2676
2677	  If unsure, say N.
2678
2679# x86_64 have no ISA slots, but can have ISA-style DMA.
2680config ISA_DMA_API
2681	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2682	default y
2683	help
2684	  Enables ISA-style DMA support for devices requiring such controllers.
2685	  If unsure, say Y.
2686
2687if X86_32
2688
2689config ISA
2690	bool "ISA support"
2691	help
2692	  Find out whether you have ISA slots on your motherboard.  ISA is the
2693	  name of a bus system, i.e. the way the CPU talks to the other stuff
2694	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2695	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2696	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2697
2698config SCx200
2699	tristate "NatSemi SCx200 support"
2700	help
2701	  This provides basic support for National Semiconductor's
2702	  (now AMD's) Geode processors.  The driver probes for the
2703	  PCI-IDs of several on-chip devices, so its a good dependency
2704	  for other scx200_* drivers.
2705
2706	  If compiled as a module, the driver is named scx200.
2707
2708config SCx200HR_TIMER
2709	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2710	depends on SCx200
2711	default y
2712	help
2713	  This driver provides a clocksource built upon the on-chip
2714	  27MHz high-resolution timer.  Its also a workaround for
2715	  NSC Geode SC-1100's buggy TSC, which loses time when the
2716	  processor goes idle (as is done by the scheduler).  The
2717	  other workaround is idle=poll boot option.
2718
2719config OLPC
2720	bool "One Laptop Per Child support"
2721	depends on !X86_PAE
2722	select GPIOLIB
2723	select OF
2724	select OF_PROMTREE
2725	select IRQ_DOMAIN
2726	select OLPC_EC
2727	help
2728	  Add support for detecting the unique features of the OLPC
2729	  XO hardware.
2730
2731config OLPC_XO1_PM
2732	bool "OLPC XO-1 Power Management"
2733	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2734	help
2735	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2736
2737config OLPC_XO1_RTC
2738	bool "OLPC XO-1 Real Time Clock"
2739	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2740	help
2741	  Add support for the XO-1 real time clock, which can be used as a
2742	  programmable wakeup source.
2743
2744config OLPC_XO1_SCI
2745	bool "OLPC XO-1 SCI extras"
2746	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2747	depends on INPUT=y
2748	select POWER_SUPPLY
2749	help
2750	  Add support for SCI-based features of the OLPC XO-1 laptop:
2751	   - EC-driven system wakeups
2752	   - Power button
2753	   - Ebook switch
2754	   - Lid switch
2755	   - AC adapter status updates
2756	   - Battery status updates
2757
2758config OLPC_XO15_SCI
2759	bool "OLPC XO-1.5 SCI extras"
2760	depends on OLPC && ACPI
2761	select POWER_SUPPLY
2762	help
2763	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2764	   - EC-driven system wakeups
2765	   - AC adapter status updates
2766	   - Battery status updates
2767
2768config ALIX
2769	bool "PCEngines ALIX System Support (LED setup)"
2770	select GPIOLIB
2771	help
2772	  This option enables system support for the PCEngines ALIX.
2773	  At present this just sets up LEDs for GPIO control on
2774	  ALIX2/3/6 boards.  However, other system specific setup should
2775	  get added here.
2776
2777	  Note: You must still enable the drivers for GPIO and LED support
2778	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2779
2780	  Note: You have to set alix.force=1 for boards with Award BIOS.
2781
2782config NET5501
2783	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2784	select GPIOLIB
2785	help
2786	  This option enables system support for the Soekris Engineering net5501.
2787
2788config GEOS
2789	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2790	select GPIOLIB
2791	depends on DMI
2792	help
2793	  This option enables system support for the Traverse Technologies GEOS.
2794
2795config TS5500
2796	bool "Technologic Systems TS-5500 platform support"
2797	depends on MELAN
2798	select CHECK_SIGNATURE
2799	select NEW_LEDS
2800	select LEDS_CLASS
2801	help
2802	  This option enables system support for the Technologic Systems TS-5500.
2803
2804endif # X86_32
2805
2806config AMD_NB
2807	def_bool y
2808	depends on CPU_SUP_AMD && PCI
2809
2810config X86_SYSFB
2811	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2812	help
2813	  Firmwares often provide initial graphics framebuffers so the BIOS,
2814	  bootloader or kernel can show basic video-output during boot for
2815	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2816	  Extensions and EFI-framebuffers for this, which are mostly limited
2817	  to x86.
2818	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2819	  framebuffers so the new generic system-framebuffer drivers can be
2820	  used on x86. If the framebuffer is not compatible with the generic
2821	  modes, it is advertised as fallback platform framebuffer so legacy
2822	  drivers like efifb, vesafb and uvesafb can pick it up.
2823	  If this option is not selected, all system framebuffers are always
2824	  marked as fallback platform framebuffers as usual.
2825
2826	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2827	  not be able to pick up generic system framebuffers if this option
2828	  is selected. You are highly encouraged to enable simplefb as
2829	  replacement if you select this option. simplefb can correctly deal
2830	  with generic system framebuffers. But you should still keep vesafb
2831	  and others enabled as fallback if a system framebuffer is
2832	  incompatible with simplefb.
2833
2834	  If unsure, say Y.
2835
2836endmenu
2837
2838
2839menu "Binary Emulations"
2840
2841config IA32_EMULATION
2842	bool "IA32 Emulation"
2843	depends on X86_64
2844	select ARCH_WANT_OLD_COMPAT_IPC
2845	select BINFMT_ELF
2846	select COMPAT_OLD_SIGACTION
2847	help
2848	  Include code to run legacy 32-bit programs under a
2849	  64-bit kernel. You should likely turn this on, unless you're
2850	  100% sure that you don't have any 32-bit programs left.
2851
2852config IA32_AOUT
2853	tristate "IA32 a.out support"
2854	depends on IA32_EMULATION
2855	depends on BROKEN
2856	help
2857	  Support old a.out binaries in the 32bit emulation.
2858
2859config X86_X32
2860	bool "x32 ABI for 64-bit mode"
2861	depends on X86_64
2862	help
2863	  Include code to run binaries for the x32 native 32-bit ABI
2864	  for 64-bit processors.  An x32 process gets access to the
2865	  full 64-bit register file and wide data path while leaving
2866	  pointers at 32 bits for smaller memory footprint.
2867
2868	  You will need a recent binutils (2.22 or later) with
2869	  elf32_x86_64 support enabled to compile a kernel with this
2870	  option set.
2871
2872config COMPAT_32
2873	def_bool y
2874	depends on IA32_EMULATION || X86_32
2875	select HAVE_UID16
2876	select OLD_SIGSUSPEND3
2877
2878config COMPAT
2879	def_bool y
2880	depends on IA32_EMULATION || X86_X32
2881
2882if COMPAT
2883config COMPAT_FOR_U64_ALIGNMENT
2884	def_bool y
2885
2886config SYSVIPC_COMPAT
2887	def_bool y
2888	depends on SYSVIPC
2889endif
2890
2891endmenu
2892
2893
2894config HAVE_ATOMIC_IOMAP
2895	def_bool y
2896	depends on X86_32
2897
2898source "drivers/firmware/Kconfig"
2899
2900source "arch/x86/kvm/Kconfig"
2901
2902source "arch/x86/Kconfig.assembler"
2903