xref: /openbmc/linux/arch/x86/Kconfig (revision 5f66f73b)
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_HAS_ACPI_TABLE_UPGRADE	if ACPI
64	select ARCH_HAS_DEBUG_VIRTUAL
65	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
66	select ARCH_HAS_DEVMEM_IS_ALLOWED
67	select ARCH_HAS_EARLY_DEBUG		if KGDB
68	select ARCH_HAS_ELF_RANDOMIZE
69	select ARCH_HAS_FAST_MULTIPLIER
70	select ARCH_HAS_FILTER_PGPROT
71	select ARCH_HAS_FORTIFY_SOURCE
72	select ARCH_HAS_GCOV_PROFILE_ALL
73	select ARCH_HAS_KCOV			if X86_64 && STACK_VALIDATION
74	select ARCH_HAS_MEM_ENCRYPT
75	select ARCH_HAS_MEMBARRIER_SYNC_CORE
76	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
77	select ARCH_HAS_PMEM_API		if X86_64
78	select ARCH_HAS_PTE_DEVMAP		if X86_64
79	select ARCH_HAS_PTE_SPECIAL
80	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
81	select ARCH_HAS_COPY_MC			if X86_64
82	select ARCH_HAS_SET_MEMORY
83	select ARCH_HAS_SET_DIRECT_MAP
84	select ARCH_HAS_STRICT_KERNEL_RWX
85	select ARCH_HAS_STRICT_MODULE_RWX
86	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
87	select ARCH_HAS_SYSCALL_WRAPPER
88	select ARCH_HAS_UBSAN_SANITIZE_ALL
89	select ARCH_HAS_DEBUG_WX
90	select ARCH_HAVE_NMI_SAFE_CMPXCHG
91	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
92	select ARCH_MIGHT_HAVE_PC_PARPORT
93	select ARCH_MIGHT_HAVE_PC_SERIO
94	select ARCH_STACKWALK
95	select ARCH_SUPPORTS_ACPI
96	select ARCH_SUPPORTS_ATOMIC_RMW
97	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
98	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
99	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
100	select ARCH_SUPPORTS_LTO_CLANG		if X86_64
101	select ARCH_SUPPORTS_LTO_CLANG_THIN	if X86_64
102	select ARCH_USE_BUILTIN_BSWAP
103	select ARCH_USE_MEMTEST
104	select ARCH_USE_QUEUED_RWLOCKS
105	select ARCH_USE_QUEUED_SPINLOCKS
106	select ARCH_USE_SYM_ANNOTATIONS
107	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
108	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
109	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
110	select ARCH_WANT_HUGE_PMD_SHARE
111	select ARCH_WANT_LD_ORPHAN_WARN
112	select ARCH_WANTS_THP_SWAP		if X86_64
113	select BUILDTIME_TABLE_SORT
114	select CLKEVT_I8253
115	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
116	select CLOCKSOURCE_WATCHDOG
117	select DCACHE_WORD_ACCESS
118	select EDAC_ATOMIC_SCRUB
119	select EDAC_SUPPORT
120	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
121	select GENERIC_CLOCKEVENTS_MIN_ADJUST
122	select GENERIC_CMOS_UPDATE
123	select GENERIC_CPU_AUTOPROBE
124	select GENERIC_CPU_VULNERABILITIES
125	select GENERIC_EARLY_IOREMAP
126	select GENERIC_ENTRY
127	select GENERIC_FIND_FIRST_BIT
128	select GENERIC_IOMAP
129	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
130	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
131	select GENERIC_IRQ_MIGRATION		if SMP
132	select GENERIC_IRQ_PROBE
133	select GENERIC_IRQ_RESERVATION_MODE
134	select GENERIC_IRQ_SHOW
135	select GENERIC_PENDING_IRQ		if SMP
136	select GENERIC_PTDUMP
137	select GENERIC_SMP_IDLE_THREAD
138	select GENERIC_STRNCPY_FROM_USER
139	select GENERIC_STRNLEN_USER
140	select GENERIC_TIME_VSYSCALL
141	select GENERIC_GETTIMEOFDAY
142	select GENERIC_VDSO_TIME_NS
143	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
144	select HARDIRQS_SW_RESEND
145	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
146	select HAVE_ACPI_APEI			if ACPI
147	select HAVE_ACPI_APEI_NMI		if ACPI
148	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
149	select HAVE_ARCH_AUDITSYSCALL
150	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
151	select HAVE_ARCH_JUMP_LABEL
152	select HAVE_ARCH_JUMP_LABEL_RELATIVE
153	select HAVE_ARCH_KASAN			if X86_64
154	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
155	select HAVE_ARCH_KFENCE
156	select HAVE_ARCH_KGDB
157	select HAVE_ARCH_MMAP_RND_BITS		if MMU
158	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
159	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
160	select HAVE_ARCH_PREL32_RELOCATIONS
161	select HAVE_ARCH_SECCOMP_FILTER
162	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
163	select HAVE_ARCH_STACKLEAK
164	select HAVE_ARCH_TRACEHOOK
165	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
166	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
167	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
168	select HAVE_ARCH_VMAP_STACK		if X86_64
169	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
170	select HAVE_ARCH_WITHIN_STACK_FRAMES
171	select HAVE_ASM_MODVERSIONS
172	select HAVE_CMPXCHG_DOUBLE
173	select HAVE_CMPXCHG_LOCAL
174	select HAVE_CONTEXT_TRACKING		if X86_64
175	select HAVE_CONTEXT_TRACKING_OFFSTACK	if HAVE_CONTEXT_TRACKING
176	select HAVE_C_RECORDMCOUNT
177	select HAVE_OBJTOOL_MCOUNT		if STACK_VALIDATION
178	select HAVE_DEBUG_KMEMLEAK
179	select HAVE_DMA_CONTIGUOUS
180	select HAVE_DYNAMIC_FTRACE
181	select HAVE_DYNAMIC_FTRACE_WITH_REGS
182	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
183	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
184	select HAVE_EBPF_JIT
185	select HAVE_EFFICIENT_UNALIGNED_ACCESS
186	select HAVE_EISA
187	select HAVE_EXIT_THREAD
188	select HAVE_FAST_GUP
189	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
190	select HAVE_FTRACE_MCOUNT_RECORD
191	select HAVE_FUNCTION_GRAPH_TRACER
192	select HAVE_FUNCTION_TRACER
193	select HAVE_GCC_PLUGINS
194	select HAVE_HW_BREAKPOINT
195	select HAVE_IDE
196	select HAVE_IOREMAP_PROT
197	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
198	select HAVE_IRQ_TIME_ACCOUNTING
199	select HAVE_KERNEL_BZIP2
200	select HAVE_KERNEL_GZIP
201	select HAVE_KERNEL_LZ4
202	select HAVE_KERNEL_LZMA
203	select HAVE_KERNEL_LZO
204	select HAVE_KERNEL_XZ
205	select HAVE_KERNEL_ZSTD
206	select HAVE_KPROBES
207	select HAVE_KPROBES_ON_FTRACE
208	select HAVE_FUNCTION_ERROR_INJECTION
209	select HAVE_KRETPROBES
210	select HAVE_KVM
211	select HAVE_LIVEPATCH			if X86_64
212	select HAVE_MIXED_BREAKPOINTS_REGS
213	select HAVE_MOD_ARCH_SPECIFIC
214	select HAVE_MOVE_PMD
215	select HAVE_MOVE_PUD
216	select HAVE_NMI
217	select HAVE_OPTPROBES
218	select HAVE_PCSPKR_PLATFORM
219	select HAVE_PERF_EVENTS
220	select HAVE_PERF_EVENTS_NMI
221	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
222	select HAVE_PCI
223	select HAVE_PERF_REGS
224	select HAVE_PERF_USER_STACK_DUMP
225	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
226	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
227	select HAVE_REGS_AND_STACK_ACCESS_API
228	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
229	select HAVE_FUNCTION_ARG_ACCESS_API
230	select HAVE_SOFTIRQ_ON_OWN_STACK
231	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
232	select HAVE_STACK_VALIDATION		if X86_64
233	select HAVE_STATIC_CALL
234	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
235	select HAVE_PREEMPT_DYNAMIC
236	select HAVE_RSEQ
237	select HAVE_SYSCALL_TRACEPOINTS
238	select HAVE_UNSTABLE_SCHED_CLOCK
239	select HAVE_USER_RETURN_NOTIFIER
240	select HAVE_GENERIC_VDSO
241	select HOTPLUG_SMT			if SMP
242	select IRQ_FORCED_THREADING
243	select NEED_SG_DMA_LENGTH
244	select PCI_DOMAINS			if PCI
245	select PCI_LOCKLESS_CONFIG		if PCI
246	select PERF_EVENTS
247	select RTC_LIB
248	select RTC_MC146818_LIB
249	select SPARSE_IRQ
250	select SRCU
251	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
252	select SYSCTL_EXCEPTION_TRACE
253	select THREAD_INFO_IN_TASK
254	select USER_STACKTRACE_SUPPORT
255	select VIRT_TO_BUS
256	select HAVE_ARCH_KCSAN			if X86_64
257	select X86_FEATURE_NAMES		if PROC_FS
258	select PROC_PID_ARCH_STATUS		if PROC_FS
259	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
260
261config INSTRUCTION_DECODER
262	def_bool y
263	depends on KPROBES || PERF_EVENTS || UPROBES
264
265config OUTPUT_FORMAT
266	string
267	default "elf32-i386" if X86_32
268	default "elf64-x86-64" if X86_64
269
270config LOCKDEP_SUPPORT
271	def_bool y
272
273config STACKTRACE_SUPPORT
274	def_bool y
275
276config MMU
277	def_bool y
278
279config ARCH_MMAP_RND_BITS_MIN
280	default 28 if 64BIT
281	default 8
282
283config ARCH_MMAP_RND_BITS_MAX
284	default 32 if 64BIT
285	default 16
286
287config ARCH_MMAP_RND_COMPAT_BITS_MIN
288	default 8
289
290config ARCH_MMAP_RND_COMPAT_BITS_MAX
291	default 16
292
293config SBUS
294	bool
295
296config GENERIC_ISA_DMA
297	def_bool y
298	depends on ISA_DMA_API
299
300config GENERIC_BUG
301	def_bool y
302	depends on BUG
303	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
304
305config GENERIC_BUG_RELATIVE_POINTERS
306	bool
307
308config ARCH_MAY_HAVE_PC_FDC
309	def_bool y
310	depends on ISA_DMA_API
311
312config GENERIC_CALIBRATE_DELAY
313	def_bool y
314
315config ARCH_HAS_CPU_RELAX
316	def_bool y
317
318config ARCH_HAS_CACHE_LINE_SIZE
319	def_bool y
320
321config ARCH_HAS_FILTER_PGPROT
322	def_bool y
323
324config HAVE_SETUP_PER_CPU_AREA
325	def_bool y
326
327config NEED_PER_CPU_EMBED_FIRST_CHUNK
328	def_bool y
329
330config NEED_PER_CPU_PAGE_FIRST_CHUNK
331	def_bool y
332
333config ARCH_HIBERNATION_POSSIBLE
334	def_bool y
335
336config ARCH_SUSPEND_POSSIBLE
337	def_bool y
338
339config ARCH_WANT_GENERAL_HUGETLB
340	def_bool y
341
342config ZONE_DMA32
343	def_bool y if X86_64
344
345config AUDIT_ARCH
346	def_bool y if X86_64
347
348config KASAN_SHADOW_OFFSET
349	hex
350	depends on KASAN
351	default 0xdffffc0000000000
352
353config HAVE_INTEL_TXT
354	def_bool y
355	depends on INTEL_IOMMU && ACPI
356
357config X86_32_SMP
358	def_bool y
359	depends on X86_32 && SMP
360
361config X86_64_SMP
362	def_bool y
363	depends on X86_64 && SMP
364
365config ARCH_SUPPORTS_UPROBES
366	def_bool y
367
368config FIX_EARLYCON_MEM
369	def_bool y
370
371config DYNAMIC_PHYSICAL_MASK
372	bool
373
374config PGTABLE_LEVELS
375	int
376	default 5 if X86_5LEVEL
377	default 4 if X86_64
378	default 3 if X86_PAE
379	default 2
380
381config CC_HAS_SANE_STACKPROTECTOR
382	bool
383	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
384	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
385	help
386	   We have to make sure stack protector is unconditionally disabled if
387	   the compiler produces broken code or if it does not let us control
388	   the segment on 32-bit kernels.
389
390menu "Processor type and features"
391
392config ZONE_DMA
393	bool "DMA memory allocation support" if EXPERT
394	default y
395	help
396	  DMA memory allocation support allows devices with less than 32-bit
397	  addressing to allocate within the first 16MB of address space.
398	  Disable if no such devices will be used.
399
400	  If unsure, say Y.
401
402config SMP
403	bool "Symmetric multi-processing support"
404	help
405	  This enables support for systems with more than one CPU. If you have
406	  a system with only one CPU, say N. If you have a system with more
407	  than one CPU, say Y.
408
409	  If you say N here, the kernel will run on uni- and multiprocessor
410	  machines, but will use only one CPU of a multiprocessor machine. If
411	  you say Y here, the kernel will run on many, but not all,
412	  uniprocessor machines. On a uniprocessor machine, the kernel
413	  will run faster if you say N here.
414
415	  Note that if you say Y here and choose architecture "586" or
416	  "Pentium" under "Processor family", the kernel will not work on 486
417	  architectures. Similarly, multiprocessor kernels for the "PPro"
418	  architecture may not work on all Pentium based boards.
419
420	  People using multiprocessor machines who say Y here should also say
421	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
422	  Management" code will be disabled if you say Y here.
423
424	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
425	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
426	  <http://www.tldp.org/docs.html#howto>.
427
428	  If you don't know what to do here, say N.
429
430config X86_FEATURE_NAMES
431	bool "Processor feature human-readable names" if EMBEDDED
432	default y
433	help
434	  This option compiles in a table of x86 feature bits and corresponding
435	  names.  This is required to support /proc/cpuinfo and a few kernel
436	  messages.  You can disable this to save space, at the expense of
437	  making those few kernel messages show numeric feature bits instead.
438
439	  If in doubt, say Y.
440
441config X86_X2APIC
442	bool "Support x2apic"
443	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
444	help
445	  This enables x2apic support on CPUs that have this feature.
446
447	  This allows 32-bit apic IDs (so it can support very large systems),
448	  and accesses the local apic via MSRs not via mmio.
449
450	  If you don't know what to do here, say N.
451
452config X86_MPPARSE
453	bool "Enable MPS table" if ACPI
454	default y
455	depends on X86_LOCAL_APIC
456	help
457	  For old smp systems that do not have proper acpi support. Newer systems
458	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
459
460config GOLDFISH
461	def_bool y
462	depends on X86_GOLDFISH
463
464config RETPOLINE
465	bool "Avoid speculative indirect branches in kernel"
466	default y
467	help
468	  Compile kernel with the retpoline compiler options to guard against
469	  kernel-to-user data leaks by avoiding speculative indirect
470	  branches. Requires a compiler with -mindirect-branch=thunk-extern
471	  support for full protection. The kernel may run slower.
472
473config X86_CPU_RESCTRL
474	bool "x86 CPU resource control support"
475	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
476	select KERNFS
477	select PROC_CPU_RESCTRL		if PROC_FS
478	help
479	  Enable x86 CPU resource control support.
480
481	  Provide support for the allocation and monitoring of system resources
482	  usage by the CPU.
483
484	  Intel calls this Intel Resource Director Technology
485	  (Intel(R) RDT). More information about RDT can be found in the
486	  Intel x86 Architecture Software Developer Manual.
487
488	  AMD calls this AMD Platform Quality of Service (AMD QoS).
489	  More information about AMD QoS can be found in the AMD64 Technology
490	  Platform Quality of Service Extensions manual.
491
492	  Say N if unsure.
493
494if X86_32
495config X86_BIGSMP
496	bool "Support for big SMP systems with more than 8 CPUs"
497	depends on SMP
498	help
499	  This option is needed for the systems that have more than 8 CPUs.
500
501config X86_EXTENDED_PLATFORM
502	bool "Support for extended (non-PC) x86 platforms"
503	default y
504	help
505	  If you disable this option then the kernel will only support
506	  standard PC platforms. (which covers the vast majority of
507	  systems out there.)
508
509	  If you enable this option then you'll be able to select support
510	  for the following (non-PC) 32 bit x86 platforms:
511		Goldfish (Android emulator)
512		AMD Elan
513		RDC R-321x SoC
514		SGI 320/540 (Visual Workstation)
515		STA2X11-based (e.g. Northville)
516		Moorestown MID devices
517
518	  If you have one of these systems, or if you want to build a
519	  generic distribution kernel, say Y here - otherwise say N.
520endif
521
522if X86_64
523config X86_EXTENDED_PLATFORM
524	bool "Support for extended (non-PC) x86 platforms"
525	default y
526	help
527	  If you disable this option then the kernel will only support
528	  standard PC platforms. (which covers the vast majority of
529	  systems out there.)
530
531	  If you enable this option then you'll be able to select support
532	  for the following (non-PC) 64 bit x86 platforms:
533		Numascale NumaChip
534		ScaleMP vSMP
535		SGI Ultraviolet
536
537	  If you have one of these systems, or if you want to build a
538	  generic distribution kernel, say Y here - otherwise say N.
539endif
540# This is an alphabetically sorted list of 64 bit extended platforms
541# Please maintain the alphabetic order if and when there are additions
542config X86_NUMACHIP
543	bool "Numascale NumaChip"
544	depends on X86_64
545	depends on X86_EXTENDED_PLATFORM
546	depends on NUMA
547	depends on SMP
548	depends on X86_X2APIC
549	depends on PCI_MMCONFIG
550	help
551	  Adds support for Numascale NumaChip large-SMP systems. Needed to
552	  enable more than ~168 cores.
553	  If you don't have one of these, you should say N here.
554
555config X86_VSMP
556	bool "ScaleMP vSMP"
557	select HYPERVISOR_GUEST
558	select PARAVIRT
559	depends on X86_64 && PCI
560	depends on X86_EXTENDED_PLATFORM
561	depends on SMP
562	help
563	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
564	  supposed to run on these EM64T-based machines.  Only choose this option
565	  if you have one of these machines.
566
567config X86_UV
568	bool "SGI Ultraviolet"
569	depends on X86_64
570	depends on X86_EXTENDED_PLATFORM
571	depends on NUMA
572	depends on EFI
573	depends on KEXEC_CORE
574	depends on X86_X2APIC
575	depends on PCI
576	help
577	  This option is needed in order to support SGI Ultraviolet systems.
578	  If you don't have one of these, you should say N here.
579
580# Following is an alphabetically sorted list of 32 bit extended platforms
581# Please maintain the alphabetic order if and when there are additions
582
583config X86_GOLDFISH
584	bool "Goldfish (Virtual Platform)"
585	depends on X86_EXTENDED_PLATFORM
586	help
587	 Enable support for the Goldfish virtual platform used primarily
588	 for Android development. Unless you are building for the Android
589	 Goldfish emulator say N here.
590
591config X86_INTEL_CE
592	bool "CE4100 TV platform"
593	depends on PCI
594	depends on PCI_GODIRECT
595	depends on X86_IO_APIC
596	depends on X86_32
597	depends on X86_EXTENDED_PLATFORM
598	select X86_REBOOTFIXUPS
599	select OF
600	select OF_EARLY_FLATTREE
601	help
602	  Select for the Intel CE media processor (CE4100) SOC.
603	  This option compiles in support for the CE4100 SOC for settop
604	  boxes and media devices.
605
606config X86_INTEL_MID
607	bool "Intel MID platform support"
608	depends on X86_EXTENDED_PLATFORM
609	depends on X86_PLATFORM_DEVICES
610	depends on PCI
611	depends on X86_64 || (PCI_GOANY && X86_32)
612	depends on X86_IO_APIC
613	select I2C
614	select DW_APB_TIMER
615	select APB_TIMER
616	select INTEL_SCU_PCI
617	select MFD_INTEL_MSIC
618	help
619	  Select to build a kernel capable of supporting Intel MID (Mobile
620	  Internet Device) platform systems which do not have the PCI legacy
621	  interfaces. If you are building for a PC class system say N here.
622
623	  Intel MID platforms are based on an Intel processor and chipset which
624	  consume less power than most of the x86 derivatives.
625
626config X86_INTEL_QUARK
627	bool "Intel Quark platform support"
628	depends on X86_32
629	depends on X86_EXTENDED_PLATFORM
630	depends on X86_PLATFORM_DEVICES
631	depends on X86_TSC
632	depends on PCI
633	depends on PCI_GOANY
634	depends on X86_IO_APIC
635	select IOSF_MBI
636	select INTEL_IMR
637	select COMMON_CLK
638	help
639	  Select to include support for Quark X1000 SoC.
640	  Say Y here if you have a Quark based system such as the Arduino
641	  compatible Intel Galileo.
642
643config X86_INTEL_LPSS
644	bool "Intel Low Power Subsystem Support"
645	depends on X86 && ACPI && PCI
646	select COMMON_CLK
647	select PINCTRL
648	select IOSF_MBI
649	help
650	  Select to build support for Intel Low Power Subsystem such as
651	  found on Intel Lynxpoint PCH. Selecting this option enables
652	  things like clock tree (common clock framework) and pincontrol
653	  which are needed by the LPSS peripheral drivers.
654
655config X86_AMD_PLATFORM_DEVICE
656	bool "AMD ACPI2Platform devices support"
657	depends on ACPI
658	select COMMON_CLK
659	select PINCTRL
660	help
661	  Select to interpret AMD specific ACPI device to platform device
662	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
663	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
664	  implemented under PINCTRL subsystem.
665
666config IOSF_MBI
667	tristate "Intel SoC IOSF Sideband support for SoC platforms"
668	depends on PCI
669	help
670	  This option enables sideband register access support for Intel SoC
671	  platforms. On these platforms the IOSF sideband is used in lieu of
672	  MSR's for some register accesses, mostly but not limited to thermal
673	  and power. Drivers may query the availability of this device to
674	  determine if they need the sideband in order to work on these
675	  platforms. The sideband is available on the following SoC products.
676	  This list is not meant to be exclusive.
677	   - BayTrail
678	   - Braswell
679	   - Quark
680
681	  You should say Y if you are running a kernel on one of these SoC's.
682
683config IOSF_MBI_DEBUG
684	bool "Enable IOSF sideband access through debugfs"
685	depends on IOSF_MBI && DEBUG_FS
686	help
687	  Select this option to expose the IOSF sideband access registers (MCR,
688	  MDR, MCRX) through debugfs to write and read register information from
689	  different units on the SoC. This is most useful for obtaining device
690	  state information for debug and analysis. As this is a general access
691	  mechanism, users of this option would have specific knowledge of the
692	  device they want to access.
693
694	  If you don't require the option or are in doubt, say N.
695
696config X86_RDC321X
697	bool "RDC R-321x SoC"
698	depends on X86_32
699	depends on X86_EXTENDED_PLATFORM
700	select M486
701	select X86_REBOOTFIXUPS
702	help
703	  This option is needed for RDC R-321x system-on-chip, also known
704	  as R-8610-(G).
705	  If you don't have one of these chips, you should say N here.
706
707config X86_32_NON_STANDARD
708	bool "Support non-standard 32-bit SMP architectures"
709	depends on X86_32 && SMP
710	depends on X86_EXTENDED_PLATFORM
711	help
712	  This option compiles in the bigsmp and STA2X11 default
713	  subarchitectures.  It is intended for a generic binary
714	  kernel. If you select them all, kernel will probe it one by
715	  one and will fallback to default.
716
717# Alphabetically sorted list of Non standard 32 bit platforms
718
719config X86_SUPPORTS_MEMORY_FAILURE
720	def_bool y
721	# MCE code calls memory_failure():
722	depends on X86_MCE
723	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
724	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
725	depends on X86_64 || !SPARSEMEM
726	select ARCH_SUPPORTS_MEMORY_FAILURE
727
728config STA2X11
729	bool "STA2X11 Companion Chip Support"
730	depends on X86_32_NON_STANDARD && PCI
731	select SWIOTLB
732	select MFD_STA2X11
733	select GPIOLIB
734	help
735	  This adds support for boards based on the STA2X11 IO-Hub,
736	  a.k.a. "ConneXt". The chip is used in place of the standard
737	  PC chipset, so all "standard" peripherals are missing. If this
738	  option is selected the kernel will still be able to boot on
739	  standard PC machines.
740
741config X86_32_IRIS
742	tristate "Eurobraille/Iris poweroff module"
743	depends on X86_32
744	help
745	  The Iris machines from EuroBraille do not have APM or ACPI support
746	  to shut themselves down properly.  A special I/O sequence is
747	  needed to do so, which is what this module does at
748	  kernel shutdown.
749
750	  This is only for Iris machines from EuroBraille.
751
752	  If unused, say N.
753
754config SCHED_OMIT_FRAME_POINTER
755	def_bool y
756	prompt "Single-depth WCHAN output"
757	depends on X86
758	help
759	  Calculate simpler /proc/<PID>/wchan values. If this option
760	  is disabled then wchan values will recurse back to the
761	  caller function. This provides more accurate wchan values,
762	  at the expense of slightly more scheduling overhead.
763
764	  If in doubt, say "Y".
765
766menuconfig HYPERVISOR_GUEST
767	bool "Linux guest support"
768	help
769	  Say Y here to enable options for running Linux under various hyper-
770	  visors. This option enables basic hypervisor detection and platform
771	  setup.
772
773	  If you say N, all options in this submenu will be skipped and
774	  disabled, and Linux guest support won't be built in.
775
776if HYPERVISOR_GUEST
777
778config PARAVIRT
779	bool "Enable paravirtualization code"
780	depends on HAVE_STATIC_CALL
781	help
782	  This changes the kernel so it can modify itself when it is run
783	  under a hypervisor, potentially improving performance significantly
784	  over full virtualization.  However, when run without a hypervisor
785	  the kernel is theoretically slower and slightly larger.
786
787config PARAVIRT_XXL
788	bool
789
790config PARAVIRT_DEBUG
791	bool "paravirt-ops debugging"
792	depends on PARAVIRT && DEBUG_KERNEL
793	help
794	  Enable to debug paravirt_ops internals.  Specifically, BUG if
795	  a paravirt_op is missing when it is called.
796
797config PARAVIRT_SPINLOCKS
798	bool "Paravirtualization layer for spinlocks"
799	depends on PARAVIRT && SMP
800	help
801	  Paravirtualized spinlocks allow a pvops backend to replace the
802	  spinlock implementation with something virtualization-friendly
803	  (for example, block the virtual CPU rather than spinning).
804
805	  It has a minimal impact on native kernels and gives a nice performance
806	  benefit on paravirtualized KVM / Xen kernels.
807
808	  If you are unsure how to answer this question, answer Y.
809
810config X86_HV_CALLBACK_VECTOR
811	def_bool n
812
813source "arch/x86/xen/Kconfig"
814
815config KVM_GUEST
816	bool "KVM Guest support (including kvmclock)"
817	depends on PARAVIRT
818	select PARAVIRT_CLOCK
819	select ARCH_CPUIDLE_HALTPOLL
820	select X86_HV_CALLBACK_VECTOR
821	default y
822	help
823	  This option enables various optimizations for running under the KVM
824	  hypervisor. It includes a paravirtualized clock, so that instead
825	  of relying on a PIT (or probably other) emulation by the
826	  underlying device model, the host provides the guest with
827	  timing infrastructure such as time of day, and system time
828
829config ARCH_CPUIDLE_HALTPOLL
830	def_bool n
831	prompt "Disable host haltpoll when loading haltpoll driver"
832	help
833	  If virtualized under KVM, disable host haltpoll.
834
835config PVH
836	bool "Support for running PVH guests"
837	help
838	  This option enables the PVH entry point for guest virtual machines
839	  as specified in the x86/HVM direct boot ABI.
840
841config PARAVIRT_TIME_ACCOUNTING
842	bool "Paravirtual steal time accounting"
843	depends on PARAVIRT
844	help
845	  Select this option to enable fine granularity task steal time
846	  accounting. Time spent executing other tasks in parallel with
847	  the current vCPU is discounted from the vCPU power. To account for
848	  that, there can be a small performance impact.
849
850	  If in doubt, say N here.
851
852config PARAVIRT_CLOCK
853	bool
854
855config JAILHOUSE_GUEST
856	bool "Jailhouse non-root cell support"
857	depends on X86_64 && PCI
858	select X86_PM_TIMER
859	help
860	  This option allows to run Linux as guest in a Jailhouse non-root
861	  cell. You can leave this option disabled if you only want to start
862	  Jailhouse and run Linux afterwards in the root cell.
863
864config ACRN_GUEST
865	bool "ACRN Guest support"
866	depends on X86_64
867	select X86_HV_CALLBACK_VECTOR
868	help
869	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
870	  a flexible, lightweight reference open-source hypervisor, built with
871	  real-time and safety-criticality in mind. It is built for embedded
872	  IOT with small footprint and real-time features. More details can be
873	  found in https://projectacrn.org/.
874
875endif #HYPERVISOR_GUEST
876
877source "arch/x86/Kconfig.cpu"
878
879config HPET_TIMER
880	def_bool X86_64
881	prompt "HPET Timer Support" if X86_32
882	help
883	  Use the IA-PC HPET (High Precision Event Timer) to manage
884	  time in preference to the PIT and RTC, if a HPET is
885	  present.
886	  HPET is the next generation timer replacing legacy 8254s.
887	  The HPET provides a stable time base on SMP
888	  systems, unlike the TSC, but it is more expensive to access,
889	  as it is off-chip.  The interface used is documented
890	  in the HPET spec, revision 1.
891
892	  You can safely choose Y here.  However, HPET will only be
893	  activated if the platform and the BIOS support this feature.
894	  Otherwise the 8254 will be used for timing services.
895
896	  Choose N to continue using the legacy 8254 timer.
897
898config HPET_EMULATE_RTC
899	def_bool y
900	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
901
902# Mark as expert because too many people got it wrong.
903# The code disables itself when not needed.
904config DMI
905	default y
906	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
907	bool "Enable DMI scanning" if EXPERT
908	help
909	  Enabled scanning of DMI to identify machine quirks. Say Y
910	  here unless you have verified that your setup is not
911	  affected by entries in the DMI blacklist. Required by PNP
912	  BIOS code.
913
914config GART_IOMMU
915	bool "Old AMD GART IOMMU support"
916	select DMA_OPS
917	select IOMMU_HELPER
918	select SWIOTLB
919	depends on X86_64 && PCI && AMD_NB
920	help
921	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
922	  GART based hardware IOMMUs.
923
924	  The GART supports full DMA access for devices with 32-bit access
925	  limitations, on systems with more than 3 GB. This is usually needed
926	  for USB, sound, many IDE/SATA chipsets and some other devices.
927
928	  Newer systems typically have a modern AMD IOMMU, supported via
929	  the CONFIG_AMD_IOMMU=y config option.
930
931	  In normal configurations this driver is only active when needed:
932	  there's more than 3 GB of memory and the system contains a
933	  32-bit limited device.
934
935	  If unsure, say Y.
936
937config MAXSMP
938	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
939	depends on X86_64 && SMP && DEBUG_KERNEL
940	select CPUMASK_OFFSTACK
941	help
942	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
943	  If unsure, say N.
944
945#
946# The maximum number of CPUs supported:
947#
948# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
949# and which can be configured interactively in the
950# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
951#
952# The ranges are different on 32-bit and 64-bit kernels, depending on
953# hardware capabilities and scalability features of the kernel.
954#
955# ( If MAXSMP is enabled we just use the highest possible value and disable
956#   interactive configuration. )
957#
958
959config NR_CPUS_RANGE_BEGIN
960	int
961	default NR_CPUS_RANGE_END if MAXSMP
962	default    1 if !SMP
963	default    2
964
965config NR_CPUS_RANGE_END
966	int
967	depends on X86_32
968	default   64 if  SMP &&  X86_BIGSMP
969	default    8 if  SMP && !X86_BIGSMP
970	default    1 if !SMP
971
972config NR_CPUS_RANGE_END
973	int
974	depends on X86_64
975	default 8192 if  SMP && CPUMASK_OFFSTACK
976	default  512 if  SMP && !CPUMASK_OFFSTACK
977	default    1 if !SMP
978
979config NR_CPUS_DEFAULT
980	int
981	depends on X86_32
982	default   32 if  X86_BIGSMP
983	default    8 if  SMP
984	default    1 if !SMP
985
986config NR_CPUS_DEFAULT
987	int
988	depends on X86_64
989	default 8192 if  MAXSMP
990	default   64 if  SMP
991	default    1 if !SMP
992
993config NR_CPUS
994	int "Maximum number of CPUs" if SMP && !MAXSMP
995	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
996	default NR_CPUS_DEFAULT
997	help
998	  This allows you to specify the maximum number of CPUs which this
999	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1000	  supported value is 8192, otherwise the maximum value is 512.  The
1001	  minimum value which makes sense is 2.
1002
1003	  This is purely to save memory: each supported CPU adds about 8KB
1004	  to the kernel image.
1005
1006config SCHED_SMT
1007	def_bool y if SMP
1008
1009config SCHED_MC
1010	def_bool y
1011	prompt "Multi-core scheduler support"
1012	depends on SMP
1013	help
1014	  Multi-core scheduler support improves the CPU scheduler's decision
1015	  making when dealing with multi-core CPU chips at a cost of slightly
1016	  increased overhead in some places. If unsure say N here.
1017
1018config SCHED_MC_PRIO
1019	bool "CPU core priorities scheduler support"
1020	depends on SCHED_MC && CPU_SUP_INTEL
1021	select X86_INTEL_PSTATE
1022	select CPU_FREQ
1023	default y
1024	help
1025	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1026	  core ordering determined at manufacturing time, which allows
1027	  certain cores to reach higher turbo frequencies (when running
1028	  single threaded workloads) than others.
1029
1030	  Enabling this kernel feature teaches the scheduler about
1031	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1032	  scheduler's CPU selection logic accordingly, so that higher
1033	  overall system performance can be achieved.
1034
1035	  This feature will have no effect on CPUs without this feature.
1036
1037	  If unsure say Y here.
1038
1039config UP_LATE_INIT
1040	def_bool y
1041	depends on !SMP && X86_LOCAL_APIC
1042
1043config X86_UP_APIC
1044	bool "Local APIC support on uniprocessors" if !PCI_MSI
1045	default PCI_MSI
1046	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1047	help
1048	  A local APIC (Advanced Programmable Interrupt Controller) is an
1049	  integrated interrupt controller in the CPU. If you have a single-CPU
1050	  system which has a processor with a local APIC, you can say Y here to
1051	  enable and use it. If you say Y here even though your machine doesn't
1052	  have a local APIC, then the kernel will still run with no slowdown at
1053	  all. The local APIC supports CPU-generated self-interrupts (timer,
1054	  performance counters), and the NMI watchdog which detects hard
1055	  lockups.
1056
1057config X86_UP_IOAPIC
1058	bool "IO-APIC support on uniprocessors"
1059	depends on X86_UP_APIC
1060	help
1061	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1062	  SMP-capable replacement for PC-style interrupt controllers. Most
1063	  SMP systems and many recent uniprocessor systems have one.
1064
1065	  If you have a single-CPU system with an IO-APIC, you can say Y here
1066	  to use it. If you say Y here even though your machine doesn't have
1067	  an IO-APIC, then the kernel will still run with no slowdown at all.
1068
1069config X86_LOCAL_APIC
1070	def_bool y
1071	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1072	select IRQ_DOMAIN_HIERARCHY
1073	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1074
1075config X86_IO_APIC
1076	def_bool y
1077	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1078
1079config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1080	bool "Reroute for broken boot IRQs"
1081	depends on X86_IO_APIC
1082	help
1083	  This option enables a workaround that fixes a source of
1084	  spurious interrupts. This is recommended when threaded
1085	  interrupt handling is used on systems where the generation of
1086	  superfluous "boot interrupts" cannot be disabled.
1087
1088	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1089	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1090	  kernel does during interrupt handling). On chipsets where this
1091	  boot IRQ generation cannot be disabled, this workaround keeps
1092	  the original IRQ line masked so that only the equivalent "boot
1093	  IRQ" is delivered to the CPUs. The workaround also tells the
1094	  kernel to set up the IRQ handler on the boot IRQ line. In this
1095	  way only one interrupt is delivered to the kernel. Otherwise
1096	  the spurious second interrupt may cause the kernel to bring
1097	  down (vital) interrupt lines.
1098
1099	  Only affects "broken" chipsets. Interrupt sharing may be
1100	  increased on these systems.
1101
1102config X86_MCE
1103	bool "Machine Check / overheating reporting"
1104	select GENERIC_ALLOCATOR
1105	default y
1106	help
1107	  Machine Check support allows the processor to notify the
1108	  kernel if it detects a problem (e.g. overheating, data corruption).
1109	  The action the kernel takes depends on the severity of the problem,
1110	  ranging from warning messages to halting the machine.
1111
1112config X86_MCELOG_LEGACY
1113	bool "Support for deprecated /dev/mcelog character device"
1114	depends on X86_MCE
1115	help
1116	  Enable support for /dev/mcelog which is needed by the old mcelog
1117	  userspace logging daemon. Consider switching to the new generation
1118	  rasdaemon solution.
1119
1120config X86_MCE_INTEL
1121	def_bool y
1122	prompt "Intel MCE features"
1123	depends on X86_MCE && X86_LOCAL_APIC
1124	help
1125	   Additional support for intel specific MCE features such as
1126	   the thermal monitor.
1127
1128config X86_MCE_AMD
1129	def_bool y
1130	prompt "AMD MCE features"
1131	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1132	help
1133	   Additional support for AMD specific MCE features such as
1134	   the DRAM Error Threshold.
1135
1136config X86_ANCIENT_MCE
1137	bool "Support for old Pentium 5 / WinChip machine checks"
1138	depends on X86_32 && X86_MCE
1139	help
1140	  Include support for machine check handling on old Pentium 5 or WinChip
1141	  systems. These typically need to be enabled explicitly on the command
1142	  line.
1143
1144config X86_MCE_THRESHOLD
1145	depends on X86_MCE_AMD || X86_MCE_INTEL
1146	def_bool y
1147
1148config X86_MCE_INJECT
1149	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1150	tristate "Machine check injector support"
1151	help
1152	  Provide support for injecting machine checks for testing purposes.
1153	  If you don't know what a machine check is and you don't do kernel
1154	  QA it is safe to say n.
1155
1156source "arch/x86/events/Kconfig"
1157
1158config X86_LEGACY_VM86
1159	bool "Legacy VM86 support"
1160	depends on X86_32
1161	help
1162	  This option allows user programs to put the CPU into V8086
1163	  mode, which is an 80286-era approximation of 16-bit real mode.
1164
1165	  Some very old versions of X and/or vbetool require this option
1166	  for user mode setting.  Similarly, DOSEMU will use it if
1167	  available to accelerate real mode DOS programs.  However, any
1168	  recent version of DOSEMU, X, or vbetool should be fully
1169	  functional even without kernel VM86 support, as they will all
1170	  fall back to software emulation. Nevertheless, if you are using
1171	  a 16-bit DOS program where 16-bit performance matters, vm86
1172	  mode might be faster than emulation and you might want to
1173	  enable this option.
1174
1175	  Note that any app that works on a 64-bit kernel is unlikely to
1176	  need this option, as 64-bit kernels don't, and can't, support
1177	  V8086 mode. This option is also unrelated to 16-bit protected
1178	  mode and is not needed to run most 16-bit programs under Wine.
1179
1180	  Enabling this option increases the complexity of the kernel
1181	  and slows down exception handling a tiny bit.
1182
1183	  If unsure, say N here.
1184
1185config VM86
1186	bool
1187	default X86_LEGACY_VM86
1188
1189config X86_16BIT
1190	bool "Enable support for 16-bit segments" if EXPERT
1191	default y
1192	depends on MODIFY_LDT_SYSCALL
1193	help
1194	  This option is required by programs like Wine to run 16-bit
1195	  protected mode legacy code on x86 processors.  Disabling
1196	  this option saves about 300 bytes on i386, or around 6K text
1197	  plus 16K runtime memory on x86-64,
1198
1199config X86_ESPFIX32
1200	def_bool y
1201	depends on X86_16BIT && X86_32
1202
1203config X86_ESPFIX64
1204	def_bool y
1205	depends on X86_16BIT && X86_64
1206
1207config X86_VSYSCALL_EMULATION
1208	bool "Enable vsyscall emulation" if EXPERT
1209	default y
1210	depends on X86_64
1211	help
1212	 This enables emulation of the legacy vsyscall page.  Disabling
1213	 it is roughly equivalent to booting with vsyscall=none, except
1214	 that it will also disable the helpful warning if a program
1215	 tries to use a vsyscall.  With this option set to N, offending
1216	 programs will just segfault, citing addresses of the form
1217	 0xffffffffff600?00.
1218
1219	 This option is required by many programs built before 2013, and
1220	 care should be used even with newer programs if set to N.
1221
1222	 Disabling this option saves about 7K of kernel size and
1223	 possibly 4K of additional runtime pagetable memory.
1224
1225config X86_IOPL_IOPERM
1226	bool "IOPERM and IOPL Emulation"
1227	default y
1228	help
1229	  This enables the ioperm() and iopl() syscalls which are necessary
1230	  for legacy applications.
1231
1232	  Legacy IOPL support is an overbroad mechanism which allows user
1233	  space aside of accessing all 65536 I/O ports also to disable
1234	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1235	  capabilities and permission from potentially active security
1236	  modules.
1237
1238	  The emulation restricts the functionality of the syscall to
1239	  only allowing the full range I/O port access, but prevents the
1240	  ability to disable interrupts from user space which would be
1241	  granted if the hardware IOPL mechanism would be used.
1242
1243config TOSHIBA
1244	tristate "Toshiba Laptop support"
1245	depends on X86_32
1246	help
1247	  This adds a driver to safely access the System Management Mode of
1248	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1249	  not work on models with a Phoenix BIOS. The System Management Mode
1250	  is used to set the BIOS and power saving options on Toshiba portables.
1251
1252	  For information on utilities to make use of this driver see the
1253	  Toshiba Linux utilities web site at:
1254	  <http://www.buzzard.org.uk/toshiba/>.
1255
1256	  Say Y if you intend to run this kernel on a Toshiba portable.
1257	  Say N otherwise.
1258
1259config I8K
1260	tristate "Dell i8k legacy laptop support"
1261	select HWMON
1262	select SENSORS_DELL_SMM
1263	help
1264	  This option enables legacy /proc/i8k userspace interface in hwmon
1265	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1266	  temperature and allows controlling fan speeds of Dell laptops via
1267	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1268	  it reports also power and hotkey status. For fan speed control is
1269	  needed userspace package i8kutils.
1270
1271	  Say Y if you intend to run this kernel on old Dell laptops or want to
1272	  use userspace package i8kutils.
1273	  Say N otherwise.
1274
1275config X86_REBOOTFIXUPS
1276	bool "Enable X86 board specific fixups for reboot"
1277	depends on X86_32
1278	help
1279	  This enables chipset and/or board specific fixups to be done
1280	  in order to get reboot to work correctly. This is only needed on
1281	  some combinations of hardware and BIOS. The symptom, for which
1282	  this config is intended, is when reboot ends with a stalled/hung
1283	  system.
1284
1285	  Currently, the only fixup is for the Geode machines using
1286	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1287
1288	  Say Y if you want to enable the fixup. Currently, it's safe to
1289	  enable this option even if you don't need it.
1290	  Say N otherwise.
1291
1292config MICROCODE
1293	bool "CPU microcode loading support"
1294	default y
1295	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1296	help
1297	  If you say Y here, you will be able to update the microcode on
1298	  Intel and AMD processors. The Intel support is for the IA32 family,
1299	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1300	  AMD support is for families 0x10 and later. You will obviously need
1301	  the actual microcode binary data itself which is not shipped with
1302	  the Linux kernel.
1303
1304	  The preferred method to load microcode from a detached initrd is described
1305	  in Documentation/x86/microcode.rst. For that you need to enable
1306	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1307	  initrd for microcode blobs.
1308
1309	  In addition, you can build the microcode into the kernel. For that you
1310	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1311	  config option.
1312
1313config MICROCODE_INTEL
1314	bool "Intel microcode loading support"
1315	depends on MICROCODE
1316	default MICROCODE
1317	help
1318	  This options enables microcode patch loading support for Intel
1319	  processors.
1320
1321	  For the current Intel microcode data package go to
1322	  <https://downloadcenter.intel.com> and search for
1323	  'Linux Processor Microcode Data File'.
1324
1325config MICROCODE_AMD
1326	bool "AMD microcode loading support"
1327	depends on MICROCODE
1328	help
1329	  If you select this option, microcode patch loading support for AMD
1330	  processors will be enabled.
1331
1332config MICROCODE_OLD_INTERFACE
1333	bool "Ancient loading interface (DEPRECATED)"
1334	default n
1335	depends on MICROCODE
1336	help
1337	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1338	  which was used by userspace tools like iucode_tool and microcode.ctl.
1339	  It is inadequate because it runs too late to be able to properly
1340	  load microcode on a machine and it needs special tools. Instead, you
1341	  should've switched to the early loading method with the initrd or
1342	  builtin microcode by now: Documentation/x86/microcode.rst
1343
1344config X86_MSR
1345	tristate "/dev/cpu/*/msr - Model-specific register support"
1346	help
1347	  This device gives privileged processes access to the x86
1348	  Model-Specific Registers (MSRs).  It is a character device with
1349	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1350	  MSR accesses are directed to a specific CPU on multi-processor
1351	  systems.
1352
1353config X86_CPUID
1354	tristate "/dev/cpu/*/cpuid - CPU information support"
1355	help
1356	  This device gives processes access to the x86 CPUID instruction to
1357	  be executed on a specific processor.  It is a character device
1358	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1359	  /dev/cpu/31/cpuid.
1360
1361choice
1362	prompt "High Memory Support"
1363	default HIGHMEM4G
1364	depends on X86_32
1365
1366config NOHIGHMEM
1367	bool "off"
1368	help
1369	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1370	  However, the address space of 32-bit x86 processors is only 4
1371	  Gigabytes large. That means that, if you have a large amount of
1372	  physical memory, not all of it can be "permanently mapped" by the
1373	  kernel. The physical memory that's not permanently mapped is called
1374	  "high memory".
1375
1376	  If you are compiling a kernel which will never run on a machine with
1377	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1378	  choice and suitable for most users). This will result in a "3GB/1GB"
1379	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1380	  space and the remaining part of the 4GB virtual memory space is used
1381	  by the kernel to permanently map as much physical memory as
1382	  possible.
1383
1384	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1385	  answer "4GB" here.
1386
1387	  If more than 4 Gigabytes is used then answer "64GB" here. This
1388	  selection turns Intel PAE (Physical Address Extension) mode on.
1389	  PAE implements 3-level paging on IA32 processors. PAE is fully
1390	  supported by Linux, PAE mode is implemented on all recent Intel
1391	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1392	  then the kernel will not boot on CPUs that don't support PAE!
1393
1394	  The actual amount of total physical memory will either be
1395	  auto detected or can be forced by using a kernel command line option
1396	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1397	  your boot loader (lilo or loadlin) about how to pass options to the
1398	  kernel at boot time.)
1399
1400	  If unsure, say "off".
1401
1402config HIGHMEM4G
1403	bool "4GB"
1404	help
1405	  Select this if you have a 32-bit processor and between 1 and 4
1406	  gigabytes of physical RAM.
1407
1408config HIGHMEM64G
1409	bool "64GB"
1410	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1411	select X86_PAE
1412	help
1413	  Select this if you have a 32-bit processor and more than 4
1414	  gigabytes of physical RAM.
1415
1416endchoice
1417
1418choice
1419	prompt "Memory split" if EXPERT
1420	default VMSPLIT_3G
1421	depends on X86_32
1422	help
1423	  Select the desired split between kernel and user memory.
1424
1425	  If the address range available to the kernel is less than the
1426	  physical memory installed, the remaining memory will be available
1427	  as "high memory". Accessing high memory is a little more costly
1428	  than low memory, as it needs to be mapped into the kernel first.
1429	  Note that increasing the kernel address space limits the range
1430	  available to user programs, making the address space there
1431	  tighter.  Selecting anything other than the default 3G/1G split
1432	  will also likely make your kernel incompatible with binary-only
1433	  kernel modules.
1434
1435	  If you are not absolutely sure what you are doing, leave this
1436	  option alone!
1437
1438	config VMSPLIT_3G
1439		bool "3G/1G user/kernel split"
1440	config VMSPLIT_3G_OPT
1441		depends on !X86_PAE
1442		bool "3G/1G user/kernel split (for full 1G low memory)"
1443	config VMSPLIT_2G
1444		bool "2G/2G user/kernel split"
1445	config VMSPLIT_2G_OPT
1446		depends on !X86_PAE
1447		bool "2G/2G user/kernel split (for full 2G low memory)"
1448	config VMSPLIT_1G
1449		bool "1G/3G user/kernel split"
1450endchoice
1451
1452config PAGE_OFFSET
1453	hex
1454	default 0xB0000000 if VMSPLIT_3G_OPT
1455	default 0x80000000 if VMSPLIT_2G
1456	default 0x78000000 if VMSPLIT_2G_OPT
1457	default 0x40000000 if VMSPLIT_1G
1458	default 0xC0000000
1459	depends on X86_32
1460
1461config HIGHMEM
1462	def_bool y
1463	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1464
1465config X86_PAE
1466	bool "PAE (Physical Address Extension) Support"
1467	depends on X86_32 && !HIGHMEM4G
1468	select PHYS_ADDR_T_64BIT
1469	select SWIOTLB
1470	help
1471	  PAE is required for NX support, and furthermore enables
1472	  larger swapspace support for non-overcommit purposes. It
1473	  has the cost of more pagetable lookup overhead, and also
1474	  consumes more pagetable space per process.
1475
1476config X86_5LEVEL
1477	bool "Enable 5-level page tables support"
1478	default y
1479	select DYNAMIC_MEMORY_LAYOUT
1480	select SPARSEMEM_VMEMMAP
1481	depends on X86_64
1482	help
1483	  5-level paging enables access to larger address space:
1484	  upto 128 PiB of virtual address space and 4 PiB of
1485	  physical address space.
1486
1487	  It will be supported by future Intel CPUs.
1488
1489	  A kernel with the option enabled can be booted on machines that
1490	  support 4- or 5-level paging.
1491
1492	  See Documentation/x86/x86_64/5level-paging.rst for more
1493	  information.
1494
1495	  Say N if unsure.
1496
1497config X86_DIRECT_GBPAGES
1498	def_bool y
1499	depends on X86_64
1500	help
1501	  Certain kernel features effectively disable kernel
1502	  linear 1 GB mappings (even if the CPU otherwise
1503	  supports them), so don't confuse the user by printing
1504	  that we have them enabled.
1505
1506config X86_CPA_STATISTICS
1507	bool "Enable statistic for Change Page Attribute"
1508	depends on DEBUG_FS
1509	help
1510	  Expose statistics about the Change Page Attribute mechanism, which
1511	  helps to determine the effectiveness of preserving large and huge
1512	  page mappings when mapping protections are changed.
1513
1514config AMD_MEM_ENCRYPT
1515	bool "AMD Secure Memory Encryption (SME) support"
1516	depends on X86_64 && CPU_SUP_AMD
1517	select DMA_COHERENT_POOL
1518	select DYNAMIC_PHYSICAL_MASK
1519	select ARCH_USE_MEMREMAP_PROT
1520	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1521	select INSTRUCTION_DECODER
1522	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
1523	help
1524	  Say yes to enable support for the encryption of system memory.
1525	  This requires an AMD processor that supports Secure Memory
1526	  Encryption (SME).
1527
1528config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1529	bool "Activate AMD Secure Memory Encryption (SME) by default"
1530	default y
1531	depends on AMD_MEM_ENCRYPT
1532	help
1533	  Say yes to have system memory encrypted by default if running on
1534	  an AMD processor that supports Secure Memory Encryption (SME).
1535
1536	  If set to Y, then the encryption of system memory can be
1537	  deactivated with the mem_encrypt=off command line option.
1538
1539	  If set to N, then the encryption of system memory can be
1540	  activated with the mem_encrypt=on command line option.
1541
1542# Common NUMA Features
1543config NUMA
1544	bool "NUMA Memory Allocation and Scheduler Support"
1545	depends on SMP
1546	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1547	default y if X86_BIGSMP
1548	help
1549	  Enable NUMA (Non-Uniform Memory Access) support.
1550
1551	  The kernel will try to allocate memory used by a CPU on the
1552	  local memory controller of the CPU and add some more
1553	  NUMA awareness to the kernel.
1554
1555	  For 64-bit this is recommended if the system is Intel Core i7
1556	  (or later), AMD Opteron, or EM64T NUMA.
1557
1558	  For 32-bit this is only needed if you boot a 32-bit
1559	  kernel on a 64-bit NUMA platform.
1560
1561	  Otherwise, you should say N.
1562
1563config AMD_NUMA
1564	def_bool y
1565	prompt "Old style AMD Opteron NUMA detection"
1566	depends on X86_64 && NUMA && PCI
1567	help
1568	  Enable AMD NUMA node topology detection.  You should say Y here if
1569	  you have a multi processor AMD system. This uses an old method to
1570	  read the NUMA configuration directly from the builtin Northbridge
1571	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1572	  which also takes priority if both are compiled in.
1573
1574config X86_64_ACPI_NUMA
1575	def_bool y
1576	prompt "ACPI NUMA detection"
1577	depends on X86_64 && NUMA && ACPI && PCI
1578	select ACPI_NUMA
1579	help
1580	  Enable ACPI SRAT based node topology detection.
1581
1582config NUMA_EMU
1583	bool "NUMA emulation"
1584	depends on NUMA
1585	help
1586	  Enable NUMA emulation. A flat machine will be split
1587	  into virtual nodes when booted with "numa=fake=N", where N is the
1588	  number of nodes. This is only useful for debugging.
1589
1590config NODES_SHIFT
1591	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1592	range 1 10
1593	default "10" if MAXSMP
1594	default "6" if X86_64
1595	default "3"
1596	depends on NEED_MULTIPLE_NODES
1597	help
1598	  Specify the maximum number of NUMA Nodes available on the target
1599	  system.  Increases memory reserved to accommodate various tables.
1600
1601config ARCH_FLATMEM_ENABLE
1602	def_bool y
1603	depends on X86_32 && !NUMA
1604
1605config ARCH_SPARSEMEM_ENABLE
1606	def_bool y
1607	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1608	select SPARSEMEM_STATIC if X86_32
1609	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1610
1611config ARCH_SPARSEMEM_DEFAULT
1612	def_bool X86_64 || (NUMA && X86_32)
1613
1614config ARCH_SELECT_MEMORY_MODEL
1615	def_bool y
1616	depends on ARCH_SPARSEMEM_ENABLE
1617
1618config ARCH_MEMORY_PROBE
1619	bool "Enable sysfs memory/probe interface"
1620	depends on X86_64 && MEMORY_HOTPLUG
1621	help
1622	  This option enables a sysfs memory/probe interface for testing.
1623	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1624	  If you are unsure how to answer this question, answer N.
1625
1626config ARCH_PROC_KCORE_TEXT
1627	def_bool y
1628	depends on X86_64 && PROC_KCORE
1629
1630config ILLEGAL_POINTER_VALUE
1631	hex
1632	default 0 if X86_32
1633	default 0xdead000000000000 if X86_64
1634
1635config X86_PMEM_LEGACY_DEVICE
1636	bool
1637
1638config X86_PMEM_LEGACY
1639	tristate "Support non-standard NVDIMMs and ADR protected memory"
1640	depends on PHYS_ADDR_T_64BIT
1641	depends on BLK_DEV
1642	select X86_PMEM_LEGACY_DEVICE
1643	select NUMA_KEEP_MEMINFO if NUMA
1644	select LIBNVDIMM
1645	help
1646	  Treat memory marked using the non-standard e820 type of 12 as used
1647	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1648	  The kernel will offer these regions to the 'pmem' driver so
1649	  they can be used for persistent storage.
1650
1651	  Say Y if unsure.
1652
1653config HIGHPTE
1654	bool "Allocate 3rd-level pagetables from highmem"
1655	depends on HIGHMEM
1656	help
1657	  The VM uses one page table entry for each page of physical memory.
1658	  For systems with a lot of RAM, this can be wasteful of precious
1659	  low memory.  Setting this option will put user-space page table
1660	  entries in high memory.
1661
1662config X86_CHECK_BIOS_CORRUPTION
1663	bool "Check for low memory corruption"
1664	help
1665	  Periodically check for memory corruption in low memory, which
1666	  is suspected to be caused by BIOS.  Even when enabled in the
1667	  configuration, it is disabled at runtime.  Enable it by
1668	  setting "memory_corruption_check=1" on the kernel command
1669	  line.  By default it scans the low 64k of memory every 60
1670	  seconds; see the memory_corruption_check_size and
1671	  memory_corruption_check_period parameters in
1672	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1673
1674	  When enabled with the default parameters, this option has
1675	  almost no overhead, as it reserves a relatively small amount
1676	  of memory and scans it infrequently.  It both detects corruption
1677	  and prevents it from affecting the running system.
1678
1679	  It is, however, intended as a diagnostic tool; if repeatable
1680	  BIOS-originated corruption always affects the same memory,
1681	  you can use memmap= to prevent the kernel from using that
1682	  memory.
1683
1684config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1685	bool "Set the default setting of memory_corruption_check"
1686	depends on X86_CHECK_BIOS_CORRUPTION
1687	default y
1688	help
1689	  Set whether the default state of memory_corruption_check is
1690	  on or off.
1691
1692config X86_RESERVE_LOW
1693	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1694	default 64
1695	range 4 640
1696	help
1697	  Specify the amount of low memory to reserve for the BIOS.
1698
1699	  The first page contains BIOS data structures that the kernel
1700	  must not use, so that page must always be reserved.
1701
1702	  By default we reserve the first 64K of physical RAM, as a
1703	  number of BIOSes are known to corrupt that memory range
1704	  during events such as suspend/resume or monitor cable
1705	  insertion, so it must not be used by the kernel.
1706
1707	  You can set this to 4 if you are absolutely sure that you
1708	  trust the BIOS to get all its memory reservations and usages
1709	  right.  If you know your BIOS have problems beyond the
1710	  default 64K area, you can set this to 640 to avoid using the
1711	  entire low memory range.
1712
1713	  If you have doubts about the BIOS (e.g. suspend/resume does
1714	  not work or there's kernel crashes after certain hardware
1715	  hotplug events) then you might want to enable
1716	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1717	  typical corruption patterns.
1718
1719	  Leave this to the default value of 64 if you are unsure.
1720
1721config MATH_EMULATION
1722	bool
1723	depends on MODIFY_LDT_SYSCALL
1724	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1725	help
1726	  Linux can emulate a math coprocessor (used for floating point
1727	  operations) if you don't have one. 486DX and Pentium processors have
1728	  a math coprocessor built in, 486SX and 386 do not, unless you added
1729	  a 487DX or 387, respectively. (The messages during boot time can
1730	  give you some hints here ["man dmesg"].) Everyone needs either a
1731	  coprocessor or this emulation.
1732
1733	  If you don't have a math coprocessor, you need to say Y here; if you
1734	  say Y here even though you have a coprocessor, the coprocessor will
1735	  be used nevertheless. (This behavior can be changed with the kernel
1736	  command line option "no387", which comes handy if your coprocessor
1737	  is broken. Try "man bootparam" or see the documentation of your boot
1738	  loader (lilo or loadlin) about how to pass options to the kernel at
1739	  boot time.) This means that it is a good idea to say Y here if you
1740	  intend to use this kernel on different machines.
1741
1742	  More information about the internals of the Linux math coprocessor
1743	  emulation can be found in <file:arch/x86/math-emu/README>.
1744
1745	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1746	  kernel, it won't hurt.
1747
1748config MTRR
1749	def_bool y
1750	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1751	help
1752	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1753	  the Memory Type Range Registers (MTRRs) may be used to control
1754	  processor access to memory ranges. This is most useful if you have
1755	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1756	  allows bus write transfers to be combined into a larger transfer
1757	  before bursting over the PCI/AGP bus. This can increase performance
1758	  of image write operations 2.5 times or more. Saying Y here creates a
1759	  /proc/mtrr file which may be used to manipulate your processor's
1760	  MTRRs. Typically the X server should use this.
1761
1762	  This code has a reasonably generic interface so that similar
1763	  control registers on other processors can be easily supported
1764	  as well:
1765
1766	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1767	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1768	  these, the ARRs are used to emulate the MTRRs.
1769	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1770	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1771	  write-combining. All of these processors are supported by this code
1772	  and it makes sense to say Y here if you have one of them.
1773
1774	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1775	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1776	  can lead to all sorts of problems, so it's good to say Y here.
1777
1778	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1779	  just add about 9 KB to your kernel.
1780
1781	  See <file:Documentation/x86/mtrr.rst> for more information.
1782
1783config MTRR_SANITIZER
1784	def_bool y
1785	prompt "MTRR cleanup support"
1786	depends on MTRR
1787	help
1788	  Convert MTRR layout from continuous to discrete, so X drivers can
1789	  add writeback entries.
1790
1791	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1792	  The largest mtrr entry size for a continuous block can be set with
1793	  mtrr_chunk_size.
1794
1795	  If unsure, say Y.
1796
1797config MTRR_SANITIZER_ENABLE_DEFAULT
1798	int "MTRR cleanup enable value (0-1)"
1799	range 0 1
1800	default "0"
1801	depends on MTRR_SANITIZER
1802	help
1803	  Enable mtrr cleanup default value
1804
1805config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1806	int "MTRR cleanup spare reg num (0-7)"
1807	range 0 7
1808	default "1"
1809	depends on MTRR_SANITIZER
1810	help
1811	  mtrr cleanup spare entries default, it can be changed via
1812	  mtrr_spare_reg_nr=N on the kernel command line.
1813
1814config X86_PAT
1815	def_bool y
1816	prompt "x86 PAT support" if EXPERT
1817	depends on MTRR
1818	help
1819	  Use PAT attributes to setup page level cache control.
1820
1821	  PATs are the modern equivalents of MTRRs and are much more
1822	  flexible than MTRRs.
1823
1824	  Say N here if you see bootup problems (boot crash, boot hang,
1825	  spontaneous reboots) or a non-working video driver.
1826
1827	  If unsure, say Y.
1828
1829config ARCH_USES_PG_UNCACHED
1830	def_bool y
1831	depends on X86_PAT
1832
1833config ARCH_RANDOM
1834	def_bool y
1835	prompt "x86 architectural random number generator" if EXPERT
1836	help
1837	  Enable the x86 architectural RDRAND instruction
1838	  (Intel Bull Mountain technology) to generate random numbers.
1839	  If supported, this is a high bandwidth, cryptographically
1840	  secure hardware random number generator.
1841
1842config X86_SMAP
1843	def_bool y
1844	prompt "Supervisor Mode Access Prevention" if EXPERT
1845	help
1846	  Supervisor Mode Access Prevention (SMAP) is a security
1847	  feature in newer Intel processors.  There is a small
1848	  performance cost if this enabled and turned on; there is
1849	  also a small increase in the kernel size if this is enabled.
1850
1851	  If unsure, say Y.
1852
1853config X86_UMIP
1854	def_bool y
1855	prompt "User Mode Instruction Prevention" if EXPERT
1856	help
1857	  User Mode Instruction Prevention (UMIP) is a security feature in
1858	  some x86 processors. If enabled, a general protection fault is
1859	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1860	  executed in user mode. These instructions unnecessarily expose
1861	  information about the hardware state.
1862
1863	  The vast majority of applications do not use these instructions.
1864	  For the very few that do, software emulation is provided in
1865	  specific cases in protected and virtual-8086 modes. Emulated
1866	  results are dummy.
1867
1868config X86_INTEL_MEMORY_PROTECTION_KEYS
1869	prompt "Memory Protection Keys"
1870	def_bool y
1871	# Note: only available in 64-bit mode
1872	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1873	select ARCH_USES_HIGH_VMA_FLAGS
1874	select ARCH_HAS_PKEYS
1875	help
1876	  Memory Protection Keys provides a mechanism for enforcing
1877	  page-based protections, but without requiring modification of the
1878	  page tables when an application changes protection domains.
1879
1880	  For details, see Documentation/core-api/protection-keys.rst
1881
1882	  If unsure, say y.
1883
1884choice
1885	prompt "TSX enable mode"
1886	depends on CPU_SUP_INTEL
1887	default X86_INTEL_TSX_MODE_OFF
1888	help
1889	  Intel's TSX (Transactional Synchronization Extensions) feature
1890	  allows to optimize locking protocols through lock elision which
1891	  can lead to a noticeable performance boost.
1892
1893	  On the other hand it has been shown that TSX can be exploited
1894	  to form side channel attacks (e.g. TAA) and chances are there
1895	  will be more of those attacks discovered in the future.
1896
1897	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1898	  might override this decision by tsx=on the command line parameter.
1899	  Even with TSX enabled, the kernel will attempt to enable the best
1900	  possible TAA mitigation setting depending on the microcode available
1901	  for the particular machine.
1902
1903	  This option allows to set the default tsx mode between tsx=on, =off
1904	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1905	  details.
1906
1907	  Say off if not sure, auto if TSX is in use but it should be used on safe
1908	  platforms or on if TSX is in use and the security aspect of tsx is not
1909	  relevant.
1910
1911config X86_INTEL_TSX_MODE_OFF
1912	bool "off"
1913	help
1914	  TSX is disabled if possible - equals to tsx=off command line parameter.
1915
1916config X86_INTEL_TSX_MODE_ON
1917	bool "on"
1918	help
1919	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1920	  line parameter.
1921
1922config X86_INTEL_TSX_MODE_AUTO
1923	bool "auto"
1924	help
1925	  TSX is enabled on TSX capable HW that is believed to be safe against
1926	  side channel attacks- equals the tsx=auto command line parameter.
1927endchoice
1928
1929config X86_SGX
1930	bool "Software Guard eXtensions (SGX)"
1931	depends on X86_64 && CPU_SUP_INTEL
1932	depends on CRYPTO=y
1933	depends on CRYPTO_SHA256=y
1934	select SRCU
1935	select MMU_NOTIFIER
1936	select NUMA_KEEP_MEMINFO if NUMA
1937	help
1938	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1939	  that can be used by applications to set aside private regions of code
1940	  and data, referred to as enclaves. An enclave's private memory can
1941	  only be accessed by code running within the enclave. Accesses from
1942	  outside the enclave, including other enclaves, are disallowed by
1943	  hardware.
1944
1945	  If unsure, say N.
1946
1947config EFI
1948	bool "EFI runtime service support"
1949	depends on ACPI
1950	select UCS2_STRING
1951	select EFI_RUNTIME_WRAPPERS
1952	help
1953	  This enables the kernel to use EFI runtime services that are
1954	  available (such as the EFI variable services).
1955
1956	  This option is only useful on systems that have EFI firmware.
1957	  In addition, you should use the latest ELILO loader available
1958	  at <http://elilo.sourceforge.net> in order to take advantage
1959	  of EFI runtime services. However, even with this option, the
1960	  resultant kernel should continue to boot on existing non-EFI
1961	  platforms.
1962
1963config EFI_STUB
1964	bool "EFI stub support"
1965	depends on EFI && !X86_USE_3DNOW
1966	depends on $(cc-option,-mabi=ms) || X86_32
1967	select RELOCATABLE
1968	help
1969	  This kernel feature allows a bzImage to be loaded directly
1970	  by EFI firmware without the use of a bootloader.
1971
1972	  See Documentation/admin-guide/efi-stub.rst for more information.
1973
1974config EFI_MIXED
1975	bool "EFI mixed-mode support"
1976	depends on EFI_STUB && X86_64
1977	help
1978	   Enabling this feature allows a 64-bit kernel to be booted
1979	   on a 32-bit firmware, provided that your CPU supports 64-bit
1980	   mode.
1981
1982	   Note that it is not possible to boot a mixed-mode enabled
1983	   kernel via the EFI boot stub - a bootloader that supports
1984	   the EFI handover protocol must be used.
1985
1986	   If unsure, say N.
1987
1988source "kernel/Kconfig.hz"
1989
1990config KEXEC
1991	bool "kexec system call"
1992	select KEXEC_CORE
1993	help
1994	  kexec is a system call that implements the ability to shutdown your
1995	  current kernel, and to start another kernel.  It is like a reboot
1996	  but it is independent of the system firmware.   And like a reboot
1997	  you can start any kernel with it, not just Linux.
1998
1999	  The name comes from the similarity to the exec system call.
2000
2001	  It is an ongoing process to be certain the hardware in a machine
2002	  is properly shutdown, so do not be surprised if this code does not
2003	  initially work for you.  As of this writing the exact hardware
2004	  interface is strongly in flux, so no good recommendation can be
2005	  made.
2006
2007config KEXEC_FILE
2008	bool "kexec file based system call"
2009	select KEXEC_CORE
2010	select BUILD_BIN2C
2011	depends on X86_64
2012	depends on CRYPTO=y
2013	depends on CRYPTO_SHA256=y
2014	help
2015	  This is new version of kexec system call. This system call is
2016	  file based and takes file descriptors as system call argument
2017	  for kernel and initramfs as opposed to list of segments as
2018	  accepted by previous system call.
2019
2020config ARCH_HAS_KEXEC_PURGATORY
2021	def_bool KEXEC_FILE
2022
2023config KEXEC_SIG
2024	bool "Verify kernel signature during kexec_file_load() syscall"
2025	depends on KEXEC_FILE
2026	help
2027
2028	  This option makes the kexec_file_load() syscall check for a valid
2029	  signature of the kernel image.  The image can still be loaded without
2030	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2031	  there's a signature that we can check, then it must be valid.
2032
2033	  In addition to this option, you need to enable signature
2034	  verification for the corresponding kernel image type being
2035	  loaded in order for this to work.
2036
2037config KEXEC_SIG_FORCE
2038	bool "Require a valid signature in kexec_file_load() syscall"
2039	depends on KEXEC_SIG
2040	help
2041	  This option makes kernel signature verification mandatory for
2042	  the kexec_file_load() syscall.
2043
2044config KEXEC_BZIMAGE_VERIFY_SIG
2045	bool "Enable bzImage signature verification support"
2046	depends on KEXEC_SIG
2047	depends on SIGNED_PE_FILE_VERIFICATION
2048	select SYSTEM_TRUSTED_KEYRING
2049	help
2050	  Enable bzImage signature verification support.
2051
2052config CRASH_DUMP
2053	bool "kernel crash dumps"
2054	depends on X86_64 || (X86_32 && HIGHMEM)
2055	help
2056	  Generate crash dump after being started by kexec.
2057	  This should be normally only set in special crash dump kernels
2058	  which are loaded in the main kernel with kexec-tools into
2059	  a specially reserved region and then later executed after
2060	  a crash by kdump/kexec. The crash dump kernel must be compiled
2061	  to a memory address not used by the main kernel or BIOS using
2062	  PHYSICAL_START, or it must be built as a relocatable image
2063	  (CONFIG_RELOCATABLE=y).
2064	  For more details see Documentation/admin-guide/kdump/kdump.rst
2065
2066config KEXEC_JUMP
2067	bool "kexec jump"
2068	depends on KEXEC && HIBERNATION
2069	help
2070	  Jump between original kernel and kexeced kernel and invoke
2071	  code in physical address mode via KEXEC
2072
2073config PHYSICAL_START
2074	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2075	default "0x1000000"
2076	help
2077	  This gives the physical address where the kernel is loaded.
2078
2079	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2080	  bzImage will decompress itself to above physical address and
2081	  run from there. Otherwise, bzImage will run from the address where
2082	  it has been loaded by the boot loader and will ignore above physical
2083	  address.
2084
2085	  In normal kdump cases one does not have to set/change this option
2086	  as now bzImage can be compiled as a completely relocatable image
2087	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2088	  address. This option is mainly useful for the folks who don't want
2089	  to use a bzImage for capturing the crash dump and want to use a
2090	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2091	  to be specifically compiled to run from a specific memory area
2092	  (normally a reserved region) and this option comes handy.
2093
2094	  So if you are using bzImage for capturing the crash dump,
2095	  leave the value here unchanged to 0x1000000 and set
2096	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2097	  for capturing the crash dump change this value to start of
2098	  the reserved region.  In other words, it can be set based on
2099	  the "X" value as specified in the "crashkernel=YM@XM"
2100	  command line boot parameter passed to the panic-ed
2101	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2102	  for more details about crash dumps.
2103
2104	  Usage of bzImage for capturing the crash dump is recommended as
2105	  one does not have to build two kernels. Same kernel can be used
2106	  as production kernel and capture kernel. Above option should have
2107	  gone away after relocatable bzImage support is introduced. But it
2108	  is present because there are users out there who continue to use
2109	  vmlinux for dump capture. This option should go away down the
2110	  line.
2111
2112	  Don't change this unless you know what you are doing.
2113
2114config RELOCATABLE
2115	bool "Build a relocatable kernel"
2116	default y
2117	help
2118	  This builds a kernel image that retains relocation information
2119	  so it can be loaded someplace besides the default 1MB.
2120	  The relocations tend to make the kernel binary about 10% larger,
2121	  but are discarded at runtime.
2122
2123	  One use is for the kexec on panic case where the recovery kernel
2124	  must live at a different physical address than the primary
2125	  kernel.
2126
2127	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2128	  it has been loaded at and the compile time physical address
2129	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2130
2131config RANDOMIZE_BASE
2132	bool "Randomize the address of the kernel image (KASLR)"
2133	depends on RELOCATABLE
2134	default y
2135	help
2136	  In support of Kernel Address Space Layout Randomization (KASLR),
2137	  this randomizes the physical address at which the kernel image
2138	  is decompressed and the virtual address where the kernel
2139	  image is mapped, as a security feature that deters exploit
2140	  attempts relying on knowledge of the location of kernel
2141	  code internals.
2142
2143	  On 64-bit, the kernel physical and virtual addresses are
2144	  randomized separately. The physical address will be anywhere
2145	  between 16MB and the top of physical memory (up to 64TB). The
2146	  virtual address will be randomized from 16MB up to 1GB (9 bits
2147	  of entropy). Note that this also reduces the memory space
2148	  available to kernel modules from 1.5GB to 1GB.
2149
2150	  On 32-bit, the kernel physical and virtual addresses are
2151	  randomized together. They will be randomized from 16MB up to
2152	  512MB (8 bits of entropy).
2153
2154	  Entropy is generated using the RDRAND instruction if it is
2155	  supported. If RDTSC is supported, its value is mixed into
2156	  the entropy pool as well. If neither RDRAND nor RDTSC are
2157	  supported, then entropy is read from the i8254 timer. The
2158	  usable entropy is limited by the kernel being built using
2159	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2160	  minimum of 2MB. As a result, only 10 bits of entropy are
2161	  theoretically possible, but the implementations are further
2162	  limited due to memory layouts.
2163
2164	  If unsure, say Y.
2165
2166# Relocation on x86 needs some additional build support
2167config X86_NEED_RELOCS
2168	def_bool y
2169	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2170
2171config PHYSICAL_ALIGN
2172	hex "Alignment value to which kernel should be aligned"
2173	default "0x200000"
2174	range 0x2000 0x1000000 if X86_32
2175	range 0x200000 0x1000000 if X86_64
2176	help
2177	  This value puts the alignment restrictions on physical address
2178	  where kernel is loaded and run from. Kernel is compiled for an
2179	  address which meets above alignment restriction.
2180
2181	  If bootloader loads the kernel at a non-aligned address and
2182	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2183	  address aligned to above value and run from there.
2184
2185	  If bootloader loads the kernel at a non-aligned address and
2186	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2187	  load address and decompress itself to the address it has been
2188	  compiled for and run from there. The address for which kernel is
2189	  compiled already meets above alignment restrictions. Hence the
2190	  end result is that kernel runs from a physical address meeting
2191	  above alignment restrictions.
2192
2193	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2194	  this value must be a multiple of 0x200000.
2195
2196	  Don't change this unless you know what you are doing.
2197
2198config DYNAMIC_MEMORY_LAYOUT
2199	bool
2200	help
2201	  This option makes base addresses of vmalloc and vmemmap as well as
2202	  __PAGE_OFFSET movable during boot.
2203
2204config RANDOMIZE_MEMORY
2205	bool "Randomize the kernel memory sections"
2206	depends on X86_64
2207	depends on RANDOMIZE_BASE
2208	select DYNAMIC_MEMORY_LAYOUT
2209	default RANDOMIZE_BASE
2210	help
2211	   Randomizes the base virtual address of kernel memory sections
2212	   (physical memory mapping, vmalloc & vmemmap). This security feature
2213	   makes exploits relying on predictable memory locations less reliable.
2214
2215	   The order of allocations remains unchanged. Entropy is generated in
2216	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2217	   configuration have in average 30,000 different possible virtual
2218	   addresses for each memory section.
2219
2220	   If unsure, say Y.
2221
2222config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2223	hex "Physical memory mapping padding" if EXPERT
2224	depends on RANDOMIZE_MEMORY
2225	default "0xa" if MEMORY_HOTPLUG
2226	default "0x0"
2227	range 0x1 0x40 if MEMORY_HOTPLUG
2228	range 0x0 0x40
2229	help
2230	   Define the padding in terabytes added to the existing physical
2231	   memory size during kernel memory randomization. It is useful
2232	   for memory hotplug support but reduces the entropy available for
2233	   address randomization.
2234
2235	   If unsure, leave at the default value.
2236
2237config HOTPLUG_CPU
2238	def_bool y
2239	depends on SMP
2240
2241config BOOTPARAM_HOTPLUG_CPU0
2242	bool "Set default setting of cpu0_hotpluggable"
2243	depends on HOTPLUG_CPU
2244	help
2245	  Set whether default state of cpu0_hotpluggable is on or off.
2246
2247	  Say Y here to enable CPU0 hotplug by default. If this switch
2248	  is turned on, there is no need to give cpu0_hotplug kernel
2249	  parameter and the CPU0 hotplug feature is enabled by default.
2250
2251	  Please note: there are two known CPU0 dependencies if you want
2252	  to enable the CPU0 hotplug feature either by this switch or by
2253	  cpu0_hotplug kernel parameter.
2254
2255	  First, resume from hibernate or suspend always starts from CPU0.
2256	  So hibernate and suspend are prevented if CPU0 is offline.
2257
2258	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2259	  offline if any interrupt can not migrate out of CPU0. There may
2260	  be other CPU0 dependencies.
2261
2262	  Please make sure the dependencies are under your control before
2263	  you enable this feature.
2264
2265	  Say N if you don't want to enable CPU0 hotplug feature by default.
2266	  You still can enable the CPU0 hotplug feature at boot by kernel
2267	  parameter cpu0_hotplug.
2268
2269config DEBUG_HOTPLUG_CPU0
2270	def_bool n
2271	prompt "Debug CPU0 hotplug"
2272	depends on HOTPLUG_CPU
2273	help
2274	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2275	  soon as possible and boots up userspace with CPU0 offlined. User
2276	  can online CPU0 back after boot time.
2277
2278	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2279	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2280	  compilation or giving cpu0_hotplug kernel parameter at boot.
2281
2282	  If unsure, say N.
2283
2284config COMPAT_VDSO
2285	def_bool n
2286	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2287	depends on COMPAT_32
2288	help
2289	  Certain buggy versions of glibc will crash if they are
2290	  presented with a 32-bit vDSO that is not mapped at the address
2291	  indicated in its segment table.
2292
2293	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2294	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2295	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2296	  the only released version with the bug, but OpenSUSE 9
2297	  contains a buggy "glibc 2.3.2".
2298
2299	  The symptom of the bug is that everything crashes on startup, saying:
2300	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2301
2302	  Saying Y here changes the default value of the vdso32 boot
2303	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2304	  This works around the glibc bug but hurts performance.
2305
2306	  If unsure, say N: if you are compiling your own kernel, you
2307	  are unlikely to be using a buggy version of glibc.
2308
2309choice
2310	prompt "vsyscall table for legacy applications"
2311	depends on X86_64
2312	default LEGACY_VSYSCALL_XONLY
2313	help
2314	  Legacy user code that does not know how to find the vDSO expects
2315	  to be able to issue three syscalls by calling fixed addresses in
2316	  kernel space. Since this location is not randomized with ASLR,
2317	  it can be used to assist security vulnerability exploitation.
2318
2319	  This setting can be changed at boot time via the kernel command
2320	  line parameter vsyscall=[emulate|xonly|none].
2321
2322	  On a system with recent enough glibc (2.14 or newer) and no
2323	  static binaries, you can say None without a performance penalty
2324	  to improve security.
2325
2326	  If unsure, select "Emulate execution only".
2327
2328	config LEGACY_VSYSCALL_EMULATE
2329		bool "Full emulation"
2330		help
2331		  The kernel traps and emulates calls into the fixed vsyscall
2332		  address mapping. This makes the mapping non-executable, but
2333		  it still contains readable known contents, which could be
2334		  used in certain rare security vulnerability exploits. This
2335		  configuration is recommended when using legacy userspace
2336		  that still uses vsyscalls along with legacy binary
2337		  instrumentation tools that require code to be readable.
2338
2339		  An example of this type of legacy userspace is running
2340		  Pin on an old binary that still uses vsyscalls.
2341
2342	config LEGACY_VSYSCALL_XONLY
2343		bool "Emulate execution only"
2344		help
2345		  The kernel traps and emulates calls into the fixed vsyscall
2346		  address mapping and does not allow reads.  This
2347		  configuration is recommended when userspace might use the
2348		  legacy vsyscall area but support for legacy binary
2349		  instrumentation of legacy code is not needed.  It mitigates
2350		  certain uses of the vsyscall area as an ASLR-bypassing
2351		  buffer.
2352
2353	config LEGACY_VSYSCALL_NONE
2354		bool "None"
2355		help
2356		  There will be no vsyscall mapping at all. This will
2357		  eliminate any risk of ASLR bypass due to the vsyscall
2358		  fixed address mapping. Attempts to use the vsyscalls
2359		  will be reported to dmesg, so that either old or
2360		  malicious userspace programs can be identified.
2361
2362endchoice
2363
2364config CMDLINE_BOOL
2365	bool "Built-in kernel command line"
2366	help
2367	  Allow for specifying boot arguments to the kernel at
2368	  build time.  On some systems (e.g. embedded ones), it is
2369	  necessary or convenient to provide some or all of the
2370	  kernel boot arguments with the kernel itself (that is,
2371	  to not rely on the boot loader to provide them.)
2372
2373	  To compile command line arguments into the kernel,
2374	  set this option to 'Y', then fill in the
2375	  boot arguments in CONFIG_CMDLINE.
2376
2377	  Systems with fully functional boot loaders (i.e. non-embedded)
2378	  should leave this option set to 'N'.
2379
2380config CMDLINE
2381	string "Built-in kernel command string"
2382	depends on CMDLINE_BOOL
2383	default ""
2384	help
2385	  Enter arguments here that should be compiled into the kernel
2386	  image and used at boot time.  If the boot loader provides a
2387	  command line at boot time, it is appended to this string to
2388	  form the full kernel command line, when the system boots.
2389
2390	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2391	  change this behavior.
2392
2393	  In most cases, the command line (whether built-in or provided
2394	  by the boot loader) should specify the device for the root
2395	  file system.
2396
2397config CMDLINE_OVERRIDE
2398	bool "Built-in command line overrides boot loader arguments"
2399	depends on CMDLINE_BOOL && CMDLINE != ""
2400	help
2401	  Set this option to 'Y' to have the kernel ignore the boot loader
2402	  command line, and use ONLY the built-in command line.
2403
2404	  This is used to work around broken boot loaders.  This should
2405	  be set to 'N' under normal conditions.
2406
2407config MODIFY_LDT_SYSCALL
2408	bool "Enable the LDT (local descriptor table)" if EXPERT
2409	default y
2410	help
2411	  Linux can allow user programs to install a per-process x86
2412	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2413	  call.  This is required to run 16-bit or segmented code such as
2414	  DOSEMU or some Wine programs.  It is also used by some very old
2415	  threading libraries.
2416
2417	  Enabling this feature adds a small amount of overhead to
2418	  context switches and increases the low-level kernel attack
2419	  surface.  Disabling it removes the modify_ldt(2) system call.
2420
2421	  Saying 'N' here may make sense for embedded or server kernels.
2422
2423source "kernel/livepatch/Kconfig"
2424
2425endmenu
2426
2427config ARCH_HAS_ADD_PAGES
2428	def_bool y
2429	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2430
2431config ARCH_ENABLE_MEMORY_HOTPLUG
2432	def_bool y
2433	depends on X86_64 || (X86_32 && HIGHMEM)
2434
2435config ARCH_ENABLE_MEMORY_HOTREMOVE
2436	def_bool y
2437	depends on MEMORY_HOTPLUG
2438
2439config USE_PERCPU_NUMA_NODE_ID
2440	def_bool y
2441	depends on NUMA
2442
2443config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2444	def_bool y
2445	depends on X86_64 || X86_PAE
2446
2447config ARCH_ENABLE_HUGEPAGE_MIGRATION
2448	def_bool y
2449	depends on X86_64 && HUGETLB_PAGE && MIGRATION
2450
2451config ARCH_ENABLE_THP_MIGRATION
2452	def_bool y
2453	depends on X86_64 && TRANSPARENT_HUGEPAGE
2454
2455menu "Power management and ACPI options"
2456
2457config ARCH_HIBERNATION_HEADER
2458	def_bool y
2459	depends on HIBERNATION
2460
2461source "kernel/power/Kconfig"
2462
2463source "drivers/acpi/Kconfig"
2464
2465config X86_APM_BOOT
2466	def_bool y
2467	depends on APM
2468
2469menuconfig APM
2470	tristate "APM (Advanced Power Management) BIOS support"
2471	depends on X86_32 && PM_SLEEP
2472	help
2473	  APM is a BIOS specification for saving power using several different
2474	  techniques. This is mostly useful for battery powered laptops with
2475	  APM compliant BIOSes. If you say Y here, the system time will be
2476	  reset after a RESUME operation, the /proc/apm device will provide
2477	  battery status information, and user-space programs will receive
2478	  notification of APM "events" (e.g. battery status change).
2479
2480	  If you select "Y" here, you can disable actual use of the APM
2481	  BIOS by passing the "apm=off" option to the kernel at boot time.
2482
2483	  Note that the APM support is almost completely disabled for
2484	  machines with more than one CPU.
2485
2486	  In order to use APM, you will need supporting software. For location
2487	  and more information, read <file:Documentation/power/apm-acpi.rst>
2488	  and the Battery Powered Linux mini-HOWTO, available from
2489	  <http://www.tldp.org/docs.html#howto>.
2490
2491	  This driver does not spin down disk drives (see the hdparm(8)
2492	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2493	  VESA-compliant "green" monitors.
2494
2495	  This driver does not support the TI 4000M TravelMate and the ACER
2496	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2497	  desktop machines also don't have compliant BIOSes, and this driver
2498	  may cause those machines to panic during the boot phase.
2499
2500	  Generally, if you don't have a battery in your machine, there isn't
2501	  much point in using this driver and you should say N. If you get
2502	  random kernel OOPSes or reboots that don't seem to be related to
2503	  anything, try disabling/enabling this option (or disabling/enabling
2504	  APM in your BIOS).
2505
2506	  Some other things you should try when experiencing seemingly random,
2507	  "weird" problems:
2508
2509	  1) make sure that you have enough swap space and that it is
2510	  enabled.
2511	  2) pass the "no-hlt" option to the kernel
2512	  3) switch on floating point emulation in the kernel and pass
2513	  the "no387" option to the kernel
2514	  4) pass the "floppy=nodma" option to the kernel
2515	  5) pass the "mem=4M" option to the kernel (thereby disabling
2516	  all but the first 4 MB of RAM)
2517	  6) make sure that the CPU is not over clocked.
2518	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2519	  8) disable the cache from your BIOS settings
2520	  9) install a fan for the video card or exchange video RAM
2521	  10) install a better fan for the CPU
2522	  11) exchange RAM chips
2523	  12) exchange the motherboard.
2524
2525	  To compile this driver as a module, choose M here: the
2526	  module will be called apm.
2527
2528if APM
2529
2530config APM_IGNORE_USER_SUSPEND
2531	bool "Ignore USER SUSPEND"
2532	help
2533	  This option will ignore USER SUSPEND requests. On machines with a
2534	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2535	  series notebooks, it is necessary to say Y because of a BIOS bug.
2536
2537config APM_DO_ENABLE
2538	bool "Enable PM at boot time"
2539	help
2540	  Enable APM features at boot time. From page 36 of the APM BIOS
2541	  specification: "When disabled, the APM BIOS does not automatically
2542	  power manage devices, enter the Standby State, enter the Suspend
2543	  State, or take power saving steps in response to CPU Idle calls."
2544	  This driver will make CPU Idle calls when Linux is idle (unless this
2545	  feature is turned off -- see "Do CPU IDLE calls", below). This
2546	  should always save battery power, but more complicated APM features
2547	  will be dependent on your BIOS implementation. You may need to turn
2548	  this option off if your computer hangs at boot time when using APM
2549	  support, or if it beeps continuously instead of suspending. Turn
2550	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2551	  T400CDT. This is off by default since most machines do fine without
2552	  this feature.
2553
2554config APM_CPU_IDLE
2555	depends on CPU_IDLE
2556	bool "Make CPU Idle calls when idle"
2557	help
2558	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2559	  On some machines, this can activate improved power savings, such as
2560	  a slowed CPU clock rate, when the machine is idle. These idle calls
2561	  are made after the idle loop has run for some length of time (e.g.,
2562	  333 mS). On some machines, this will cause a hang at boot time or
2563	  whenever the CPU becomes idle. (On machines with more than one CPU,
2564	  this option does nothing.)
2565
2566config APM_DISPLAY_BLANK
2567	bool "Enable console blanking using APM"
2568	help
2569	  Enable console blanking using the APM. Some laptops can use this to
2570	  turn off the LCD backlight when the screen blanker of the Linux
2571	  virtual console blanks the screen. Note that this is only used by
2572	  the virtual console screen blanker, and won't turn off the backlight
2573	  when using the X Window system. This also doesn't have anything to
2574	  do with your VESA-compliant power-saving monitor. Further, this
2575	  option doesn't work for all laptops -- it might not turn off your
2576	  backlight at all, or it might print a lot of errors to the console,
2577	  especially if you are using gpm.
2578
2579config APM_ALLOW_INTS
2580	bool "Allow interrupts during APM BIOS calls"
2581	help
2582	  Normally we disable external interrupts while we are making calls to
2583	  the APM BIOS as a measure to lessen the effects of a badly behaving
2584	  BIOS implementation.  The BIOS should reenable interrupts if it
2585	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2586	  many of the newer IBM Thinkpads.  If you experience hangs when you
2587	  suspend, try setting this to Y.  Otherwise, say N.
2588
2589endif # APM
2590
2591source "drivers/cpufreq/Kconfig"
2592
2593source "drivers/cpuidle/Kconfig"
2594
2595source "drivers/idle/Kconfig"
2596
2597endmenu
2598
2599
2600menu "Bus options (PCI etc.)"
2601
2602choice
2603	prompt "PCI access mode"
2604	depends on X86_32 && PCI
2605	default PCI_GOANY
2606	help
2607	  On PCI systems, the BIOS can be used to detect the PCI devices and
2608	  determine their configuration. However, some old PCI motherboards
2609	  have BIOS bugs and may crash if this is done. Also, some embedded
2610	  PCI-based systems don't have any BIOS at all. Linux can also try to
2611	  detect the PCI hardware directly without using the BIOS.
2612
2613	  With this option, you can specify how Linux should detect the
2614	  PCI devices. If you choose "BIOS", the BIOS will be used,
2615	  if you choose "Direct", the BIOS won't be used, and if you
2616	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2617	  If you choose "Any", the kernel will try MMCONFIG, then the
2618	  direct access method and falls back to the BIOS if that doesn't
2619	  work. If unsure, go with the default, which is "Any".
2620
2621config PCI_GOBIOS
2622	bool "BIOS"
2623
2624config PCI_GOMMCONFIG
2625	bool "MMConfig"
2626
2627config PCI_GODIRECT
2628	bool "Direct"
2629
2630config PCI_GOOLPC
2631	bool "OLPC XO-1"
2632	depends on OLPC
2633
2634config PCI_GOANY
2635	bool "Any"
2636
2637endchoice
2638
2639config PCI_BIOS
2640	def_bool y
2641	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2642
2643# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2644config PCI_DIRECT
2645	def_bool y
2646	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2647
2648config PCI_MMCONFIG
2649	bool "Support mmconfig PCI config space access" if X86_64
2650	default y
2651	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2652	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2653
2654config PCI_OLPC
2655	def_bool y
2656	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2657
2658config PCI_XEN
2659	def_bool y
2660	depends on PCI && XEN
2661	select SWIOTLB_XEN
2662
2663config MMCONF_FAM10H
2664	def_bool y
2665	depends on X86_64 && PCI_MMCONFIG && ACPI
2666
2667config PCI_CNB20LE_QUIRK
2668	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2669	depends on PCI
2670	help
2671	  Read the PCI windows out of the CNB20LE host bridge. This allows
2672	  PCI hotplug to work on systems with the CNB20LE chipset which do
2673	  not have ACPI.
2674
2675	  There's no public spec for this chipset, and this functionality
2676	  is known to be incomplete.
2677
2678	  You should say N unless you know you need this.
2679
2680config ISA_BUS
2681	bool "ISA bus support on modern systems" if EXPERT
2682	help
2683	  Expose ISA bus device drivers and options available for selection and
2684	  configuration. Enable this option if your target machine has an ISA
2685	  bus. ISA is an older system, displaced by PCI and newer bus
2686	  architectures -- if your target machine is modern, it probably does
2687	  not have an ISA bus.
2688
2689	  If unsure, say N.
2690
2691# x86_64 have no ISA slots, but can have ISA-style DMA.
2692config ISA_DMA_API
2693	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2694	default y
2695	help
2696	  Enables ISA-style DMA support for devices requiring such controllers.
2697	  If unsure, say Y.
2698
2699if X86_32
2700
2701config ISA
2702	bool "ISA support"
2703	help
2704	  Find out whether you have ISA slots on your motherboard.  ISA is the
2705	  name of a bus system, i.e. the way the CPU talks to the other stuff
2706	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2707	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2708	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2709
2710config SCx200
2711	tristate "NatSemi SCx200 support"
2712	help
2713	  This provides basic support for National Semiconductor's
2714	  (now AMD's) Geode processors.  The driver probes for the
2715	  PCI-IDs of several on-chip devices, so its a good dependency
2716	  for other scx200_* drivers.
2717
2718	  If compiled as a module, the driver is named scx200.
2719
2720config SCx200HR_TIMER
2721	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2722	depends on SCx200
2723	default y
2724	help
2725	  This driver provides a clocksource built upon the on-chip
2726	  27MHz high-resolution timer.  Its also a workaround for
2727	  NSC Geode SC-1100's buggy TSC, which loses time when the
2728	  processor goes idle (as is done by the scheduler).  The
2729	  other workaround is idle=poll boot option.
2730
2731config OLPC
2732	bool "One Laptop Per Child support"
2733	depends on !X86_PAE
2734	select GPIOLIB
2735	select OF
2736	select OF_PROMTREE
2737	select IRQ_DOMAIN
2738	select OLPC_EC
2739	help
2740	  Add support for detecting the unique features of the OLPC
2741	  XO hardware.
2742
2743config OLPC_XO1_PM
2744	bool "OLPC XO-1 Power Management"
2745	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2746	help
2747	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2748
2749config OLPC_XO1_RTC
2750	bool "OLPC XO-1 Real Time Clock"
2751	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2752	help
2753	  Add support for the XO-1 real time clock, which can be used as a
2754	  programmable wakeup source.
2755
2756config OLPC_XO1_SCI
2757	bool "OLPC XO-1 SCI extras"
2758	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2759	depends on INPUT=y
2760	select POWER_SUPPLY
2761	help
2762	  Add support for SCI-based features of the OLPC XO-1 laptop:
2763	   - EC-driven system wakeups
2764	   - Power button
2765	   - Ebook switch
2766	   - Lid switch
2767	   - AC adapter status updates
2768	   - Battery status updates
2769
2770config OLPC_XO15_SCI
2771	bool "OLPC XO-1.5 SCI extras"
2772	depends on OLPC && ACPI
2773	select POWER_SUPPLY
2774	help
2775	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2776	   - EC-driven system wakeups
2777	   - AC adapter status updates
2778	   - Battery status updates
2779
2780config ALIX
2781	bool "PCEngines ALIX System Support (LED setup)"
2782	select GPIOLIB
2783	help
2784	  This option enables system support for the PCEngines ALIX.
2785	  At present this just sets up LEDs for GPIO control on
2786	  ALIX2/3/6 boards.  However, other system specific setup should
2787	  get added here.
2788
2789	  Note: You must still enable the drivers for GPIO and LED support
2790	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2791
2792	  Note: You have to set alix.force=1 for boards with Award BIOS.
2793
2794config NET5501
2795	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2796	select GPIOLIB
2797	help
2798	  This option enables system support for the Soekris Engineering net5501.
2799
2800config GEOS
2801	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2802	select GPIOLIB
2803	depends on DMI
2804	help
2805	  This option enables system support for the Traverse Technologies GEOS.
2806
2807config TS5500
2808	bool "Technologic Systems TS-5500 platform support"
2809	depends on MELAN
2810	select CHECK_SIGNATURE
2811	select NEW_LEDS
2812	select LEDS_CLASS
2813	help
2814	  This option enables system support for the Technologic Systems TS-5500.
2815
2816endif # X86_32
2817
2818config AMD_NB
2819	def_bool y
2820	depends on CPU_SUP_AMD && PCI
2821
2822config X86_SYSFB
2823	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2824	help
2825	  Firmwares often provide initial graphics framebuffers so the BIOS,
2826	  bootloader or kernel can show basic video-output during boot for
2827	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2828	  Extensions and EFI-framebuffers for this, which are mostly limited
2829	  to x86.
2830	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2831	  framebuffers so the new generic system-framebuffer drivers can be
2832	  used on x86. If the framebuffer is not compatible with the generic
2833	  modes, it is advertised as fallback platform framebuffer so legacy
2834	  drivers like efifb, vesafb and uvesafb can pick it up.
2835	  If this option is not selected, all system framebuffers are always
2836	  marked as fallback platform framebuffers as usual.
2837
2838	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2839	  not be able to pick up generic system framebuffers if this option
2840	  is selected. You are highly encouraged to enable simplefb as
2841	  replacement if you select this option. simplefb can correctly deal
2842	  with generic system framebuffers. But you should still keep vesafb
2843	  and others enabled as fallback if a system framebuffer is
2844	  incompatible with simplefb.
2845
2846	  If unsure, say Y.
2847
2848endmenu
2849
2850
2851menu "Binary Emulations"
2852
2853config IA32_EMULATION
2854	bool "IA32 Emulation"
2855	depends on X86_64
2856	select ARCH_WANT_OLD_COMPAT_IPC
2857	select BINFMT_ELF
2858	select COMPAT_OLD_SIGACTION
2859	help
2860	  Include code to run legacy 32-bit programs under a
2861	  64-bit kernel. You should likely turn this on, unless you're
2862	  100% sure that you don't have any 32-bit programs left.
2863
2864config IA32_AOUT
2865	tristate "IA32 a.out support"
2866	depends on IA32_EMULATION
2867	depends on BROKEN
2868	help
2869	  Support old a.out binaries in the 32bit emulation.
2870
2871config X86_X32
2872	bool "x32 ABI for 64-bit mode"
2873	depends on X86_64
2874	help
2875	  Include code to run binaries for the x32 native 32-bit ABI
2876	  for 64-bit processors.  An x32 process gets access to the
2877	  full 64-bit register file and wide data path while leaving
2878	  pointers at 32 bits for smaller memory footprint.
2879
2880	  You will need a recent binutils (2.22 or later) with
2881	  elf32_x86_64 support enabled to compile a kernel with this
2882	  option set.
2883
2884config COMPAT_32
2885	def_bool y
2886	depends on IA32_EMULATION || X86_32
2887	select HAVE_UID16
2888	select OLD_SIGSUSPEND3
2889
2890config COMPAT
2891	def_bool y
2892	depends on IA32_EMULATION || X86_X32
2893
2894if COMPAT
2895config COMPAT_FOR_U64_ALIGNMENT
2896	def_bool y
2897
2898config SYSVIPC_COMPAT
2899	def_bool y
2900	depends on SYSVIPC
2901endif
2902
2903endmenu
2904
2905
2906config HAVE_ATOMIC_IOMAP
2907	def_bool y
2908	depends on X86_32
2909
2910source "drivers/firmware/Kconfig"
2911
2912source "arch/x86/kvm/Kconfig"
2913
2914source "arch/x86/Kconfig.assembler"
2915