xref: /openbmc/linux/arch/x86/Kconfig (revision 3aa139aa9fdc138a84243dc49dc18d9b40e1c6e4)
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_QUEUED_RWLOCKS
104	select ARCH_USE_QUEUED_SPINLOCKS
105	select ARCH_USE_SYM_ANNOTATIONS
106	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
107	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
108	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
109	select ARCH_WANT_HUGE_PMD_SHARE
110	select ARCH_WANT_LD_ORPHAN_WARN
111	select ARCH_WANTS_THP_SWAP		if X86_64
112	select BUILDTIME_TABLE_SORT
113	select CLKEVT_I8253
114	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
115	select CLOCKSOURCE_WATCHDOG
116	select DCACHE_WORD_ACCESS
117	select EDAC_ATOMIC_SCRUB
118	select EDAC_SUPPORT
119	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
120	select GENERIC_CLOCKEVENTS_MIN_ADJUST
121	select GENERIC_CMOS_UPDATE
122	select GENERIC_CPU_AUTOPROBE
123	select GENERIC_CPU_VULNERABILITIES
124	select GENERIC_EARLY_IOREMAP
125	select GENERIC_ENTRY
126	select GENERIC_FIND_FIRST_BIT
127	select GENERIC_IOMAP
128	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
129	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
130	select GENERIC_IRQ_MIGRATION		if SMP
131	select GENERIC_IRQ_PROBE
132	select GENERIC_IRQ_RESERVATION_MODE
133	select GENERIC_IRQ_SHOW
134	select GENERIC_PENDING_IRQ		if SMP
135	select GENERIC_PTDUMP
136	select GENERIC_SMP_IDLE_THREAD
137	select GENERIC_STRNCPY_FROM_USER
138	select GENERIC_STRNLEN_USER
139	select GENERIC_TIME_VSYSCALL
140	select GENERIC_GETTIMEOFDAY
141	select GENERIC_VDSO_TIME_NS
142	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
143	select HARDIRQS_SW_RESEND
144	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
145	select HAVE_ACPI_APEI			if ACPI
146	select HAVE_ACPI_APEI_NMI		if ACPI
147	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
148	select HAVE_ARCH_AUDITSYSCALL
149	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
150	select HAVE_ARCH_JUMP_LABEL
151	select HAVE_ARCH_JUMP_LABEL_RELATIVE
152	select HAVE_ARCH_KASAN			if X86_64
153	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
154	select HAVE_ARCH_KFENCE
155	select HAVE_ARCH_KGDB
156	select HAVE_ARCH_MMAP_RND_BITS		if MMU
157	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
158	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
159	select HAVE_ARCH_PREL32_RELOCATIONS
160	select HAVE_ARCH_SECCOMP_FILTER
161	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
162	select HAVE_ARCH_STACKLEAK
163	select HAVE_ARCH_TRACEHOOK
164	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
165	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
166	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
167	select HAVE_ARCH_VMAP_STACK		if X86_64
168	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
169	select HAVE_ARCH_WITHIN_STACK_FRAMES
170	select HAVE_ASM_MODVERSIONS
171	select HAVE_CMPXCHG_DOUBLE
172	select HAVE_CMPXCHG_LOCAL
173	select HAVE_CONTEXT_TRACKING		if X86_64
174	select HAVE_CONTEXT_TRACKING_OFFSTACK	if HAVE_CONTEXT_TRACKING
175	select HAVE_C_RECORDMCOUNT
176	select HAVE_OBJTOOL_MCOUNT		if STACK_VALIDATION
177	select HAVE_DEBUG_KMEMLEAK
178	select HAVE_DMA_CONTIGUOUS
179	select HAVE_DYNAMIC_FTRACE
180	select HAVE_DYNAMIC_FTRACE_WITH_REGS
181	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
182	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
183	select HAVE_EBPF_JIT
184	select HAVE_EFFICIENT_UNALIGNED_ACCESS
185	select HAVE_EISA
186	select HAVE_EXIT_THREAD
187	select HAVE_FAST_GUP
188	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
189	select HAVE_FTRACE_MCOUNT_RECORD
190	select HAVE_FUNCTION_GRAPH_TRACER
191	select HAVE_FUNCTION_TRACER
192	select HAVE_GCC_PLUGINS
193	select HAVE_HW_BREAKPOINT
194	select HAVE_IDE
195	select HAVE_IOREMAP_PROT
196	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
197	select HAVE_IRQ_TIME_ACCOUNTING
198	select HAVE_KERNEL_BZIP2
199	select HAVE_KERNEL_GZIP
200	select HAVE_KERNEL_LZ4
201	select HAVE_KERNEL_LZMA
202	select HAVE_KERNEL_LZO
203	select HAVE_KERNEL_XZ
204	select HAVE_KERNEL_ZSTD
205	select HAVE_KPROBES
206	select HAVE_KPROBES_ON_FTRACE
207	select HAVE_FUNCTION_ERROR_INJECTION
208	select HAVE_KRETPROBES
209	select HAVE_KVM
210	select HAVE_LIVEPATCH			if X86_64
211	select HAVE_MIXED_BREAKPOINTS_REGS
212	select HAVE_MOD_ARCH_SPECIFIC
213	select HAVE_MOVE_PMD
214	select HAVE_MOVE_PUD
215	select HAVE_NMI
216	select HAVE_OPTPROBES
217	select HAVE_PCSPKR_PLATFORM
218	select HAVE_PERF_EVENTS
219	select HAVE_PERF_EVENTS_NMI
220	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
221	select HAVE_PCI
222	select HAVE_PERF_REGS
223	select HAVE_PERF_USER_STACK_DUMP
224	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
225	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
226	select HAVE_REGS_AND_STACK_ACCESS_API
227	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
228	select HAVE_FUNCTION_ARG_ACCESS_API
229	select HAVE_SOFTIRQ_ON_OWN_STACK
230	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
231	select HAVE_STACK_VALIDATION		if X86_64
232	select HAVE_STATIC_CALL
233	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
234	select HAVE_PREEMPT_DYNAMIC
235	select HAVE_RSEQ
236	select HAVE_SYSCALL_TRACEPOINTS
237	select HAVE_UNSTABLE_SCHED_CLOCK
238	select HAVE_USER_RETURN_NOTIFIER
239	select HAVE_GENERIC_VDSO
240	select HOTPLUG_SMT			if SMP
241	select IRQ_FORCED_THREADING
242	select NEED_SG_DMA_LENGTH
243	select PCI_DOMAINS			if PCI
244	select PCI_LOCKLESS_CONFIG		if PCI
245	select PERF_EVENTS
246	select RTC_LIB
247	select RTC_MC146818_LIB
248	select SPARSE_IRQ
249	select SRCU
250	select STACK_VALIDATION			if HAVE_STACK_VALIDATION && (HAVE_STATIC_CALL_INLINE || RETPOLINE)
251	select SYSCTL_EXCEPTION_TRACE
252	select THREAD_INFO_IN_TASK
253	select USER_STACKTRACE_SUPPORT
254	select VIRT_TO_BUS
255	select HAVE_ARCH_KCSAN			if X86_64
256	select X86_FEATURE_NAMES		if PROC_FS
257	select PROC_PID_ARCH_STATUS		if PROC_FS
258	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
259
260config INSTRUCTION_DECODER
261	def_bool y
262	depends on KPROBES || PERF_EVENTS || UPROBES
263
264config OUTPUT_FORMAT
265	string
266	default "elf32-i386" if X86_32
267	default "elf64-x86-64" if X86_64
268
269config LOCKDEP_SUPPORT
270	def_bool y
271
272config STACKTRACE_SUPPORT
273	def_bool y
274
275config MMU
276	def_bool y
277
278config ARCH_MMAP_RND_BITS_MIN
279	default 28 if 64BIT
280	default 8
281
282config ARCH_MMAP_RND_BITS_MAX
283	default 32 if 64BIT
284	default 16
285
286config ARCH_MMAP_RND_COMPAT_BITS_MIN
287	default 8
288
289config ARCH_MMAP_RND_COMPAT_BITS_MAX
290	default 16
291
292config SBUS
293	bool
294
295config GENERIC_ISA_DMA
296	def_bool y
297	depends on ISA_DMA_API
298
299config GENERIC_BUG
300	def_bool y
301	depends on BUG
302	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
303
304config GENERIC_BUG_RELATIVE_POINTERS
305	bool
306
307config ARCH_MAY_HAVE_PC_FDC
308	def_bool y
309	depends on ISA_DMA_API
310
311config GENERIC_CALIBRATE_DELAY
312	def_bool y
313
314config ARCH_HAS_CPU_RELAX
315	def_bool y
316
317config ARCH_HAS_CACHE_LINE_SIZE
318	def_bool y
319
320config ARCH_HAS_FILTER_PGPROT
321	def_bool y
322
323config HAVE_SETUP_PER_CPU_AREA
324	def_bool y
325
326config NEED_PER_CPU_EMBED_FIRST_CHUNK
327	def_bool y
328
329config NEED_PER_CPU_PAGE_FIRST_CHUNK
330	def_bool y
331
332config ARCH_HIBERNATION_POSSIBLE
333	def_bool y
334
335config ARCH_SUSPEND_POSSIBLE
336	def_bool y
337
338config ARCH_WANT_GENERAL_HUGETLB
339	def_bool y
340
341config ZONE_DMA32
342	def_bool y if X86_64
343
344config AUDIT_ARCH
345	def_bool y if X86_64
346
347config KASAN_SHADOW_OFFSET
348	hex
349	depends on KASAN
350	default 0xdffffc0000000000
351
352config HAVE_INTEL_TXT
353	def_bool y
354	depends on INTEL_IOMMU && ACPI
355
356config X86_32_SMP
357	def_bool y
358	depends on X86_32 && SMP
359
360config X86_64_SMP
361	def_bool y
362	depends on X86_64 && SMP
363
364config ARCH_SUPPORTS_UPROBES
365	def_bool y
366
367config FIX_EARLYCON_MEM
368	def_bool y
369
370config DYNAMIC_PHYSICAL_MASK
371	bool
372
373config PGTABLE_LEVELS
374	int
375	default 5 if X86_5LEVEL
376	default 4 if X86_64
377	default 3 if X86_PAE
378	default 2
379
380config CC_HAS_SANE_STACKPROTECTOR
381	bool
382	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
383	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
384	help
385	   We have to make sure stack protector is unconditionally disabled if
386	   the compiler produces broken code or if it does not let us control
387	   the segment on 32-bit kernels.
388
389menu "Processor type and features"
390
391config ZONE_DMA
392	bool "DMA memory allocation support" if EXPERT
393	default y
394	help
395	  DMA memory allocation support allows devices with less than 32-bit
396	  addressing to allocate within the first 16MB of address space.
397	  Disable if no such devices will be used.
398
399	  If unsure, say Y.
400
401config SMP
402	bool "Symmetric multi-processing support"
403	help
404	  This enables support for systems with more than one CPU. If you have
405	  a system with only one CPU, say N. If you have a system with more
406	  than one CPU, say Y.
407
408	  If you say N here, the kernel will run on uni- and multiprocessor
409	  machines, but will use only one CPU of a multiprocessor machine. If
410	  you say Y here, the kernel will run on many, but not all,
411	  uniprocessor machines. On a uniprocessor machine, the kernel
412	  will run faster if you say N here.
413
414	  Note that if you say Y here and choose architecture "586" or
415	  "Pentium" under "Processor family", the kernel will not work on 486
416	  architectures. Similarly, multiprocessor kernels for the "PPro"
417	  architecture may not work on all Pentium based boards.
418
419	  People using multiprocessor machines who say Y here should also say
420	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
421	  Management" code will be disabled if you say Y here.
422
423	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
424	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
425	  <http://www.tldp.org/docs.html#howto>.
426
427	  If you don't know what to do here, say N.
428
429config X86_FEATURE_NAMES
430	bool "Processor feature human-readable names" if EMBEDDED
431	default y
432	help
433	  This option compiles in a table of x86 feature bits and corresponding
434	  names.  This is required to support /proc/cpuinfo and a few kernel
435	  messages.  You can disable this to save space, at the expense of
436	  making those few kernel messages show numeric feature bits instead.
437
438	  If in doubt, say Y.
439
440config X86_X2APIC
441	bool "Support x2apic"
442	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
443	help
444	  This enables x2apic support on CPUs that have this feature.
445
446	  This allows 32-bit apic IDs (so it can support very large systems),
447	  and accesses the local apic via MSRs not via mmio.
448
449	  If you don't know what to do here, say N.
450
451config X86_MPPARSE
452	bool "Enable MPS table" if ACPI
453	default y
454	depends on X86_LOCAL_APIC
455	help
456	  For old smp systems that do not have proper acpi support. Newer systems
457	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
458
459config GOLDFISH
460	def_bool y
461	depends on X86_GOLDFISH
462
463config RETPOLINE
464	bool "Avoid speculative indirect branches in kernel"
465	default y
466	help
467	  Compile kernel with the retpoline compiler options to guard against
468	  kernel-to-user data leaks by avoiding speculative indirect
469	  branches. Requires a compiler with -mindirect-branch=thunk-extern
470	  support for full protection. The kernel may run slower.
471
472config X86_CPU_RESCTRL
473	bool "x86 CPU resource control support"
474	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
475	select KERNFS
476	select PROC_CPU_RESCTRL		if PROC_FS
477	help
478	  Enable x86 CPU resource control support.
479
480	  Provide support for the allocation and monitoring of system resources
481	  usage by the CPU.
482
483	  Intel calls this Intel Resource Director Technology
484	  (Intel(R) RDT). More information about RDT can be found in the
485	  Intel x86 Architecture Software Developer Manual.
486
487	  AMD calls this AMD Platform Quality of Service (AMD QoS).
488	  More information about AMD QoS can be found in the AMD64 Technology
489	  Platform Quality of Service Extensions manual.
490
491	  Say N if unsure.
492
493if X86_32
494config X86_BIGSMP
495	bool "Support for big SMP systems with more than 8 CPUs"
496	depends on SMP
497	help
498	  This option is needed for the systems that have more than 8 CPUs.
499
500config X86_EXTENDED_PLATFORM
501	bool "Support for extended (non-PC) x86 platforms"
502	default y
503	help
504	  If you disable this option then the kernel will only support
505	  standard PC platforms. (which covers the vast majority of
506	  systems out there.)
507
508	  If you enable this option then you'll be able to select support
509	  for the following (non-PC) 32 bit x86 platforms:
510		Goldfish (Android emulator)
511		AMD Elan
512		RDC R-321x SoC
513		SGI 320/540 (Visual Workstation)
514		STA2X11-based (e.g. Northville)
515		Moorestown MID devices
516
517	  If you have one of these systems, or if you want to build a
518	  generic distribution kernel, say Y here - otherwise say N.
519endif
520
521if X86_64
522config X86_EXTENDED_PLATFORM
523	bool "Support for extended (non-PC) x86 platforms"
524	default y
525	help
526	  If you disable this option then the kernel will only support
527	  standard PC platforms. (which covers the vast majority of
528	  systems out there.)
529
530	  If you enable this option then you'll be able to select support
531	  for the following (non-PC) 64 bit x86 platforms:
532		Numascale NumaChip
533		ScaleMP vSMP
534		SGI Ultraviolet
535
536	  If you have one of these systems, or if you want to build a
537	  generic distribution kernel, say Y here - otherwise say N.
538endif
539# This is an alphabetically sorted list of 64 bit extended platforms
540# Please maintain the alphabetic order if and when there are additions
541config X86_NUMACHIP
542	bool "Numascale NumaChip"
543	depends on X86_64
544	depends on X86_EXTENDED_PLATFORM
545	depends on NUMA
546	depends on SMP
547	depends on X86_X2APIC
548	depends on PCI_MMCONFIG
549	help
550	  Adds support for Numascale NumaChip large-SMP systems. Needed to
551	  enable more than ~168 cores.
552	  If you don't have one of these, you should say N here.
553
554config X86_VSMP
555	bool "ScaleMP vSMP"
556	select HYPERVISOR_GUEST
557	select PARAVIRT
558	depends on X86_64 && PCI
559	depends on X86_EXTENDED_PLATFORM
560	depends on SMP
561	help
562	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
563	  supposed to run on these EM64T-based machines.  Only choose this option
564	  if you have one of these machines.
565
566config X86_UV
567	bool "SGI Ultraviolet"
568	depends on X86_64
569	depends on X86_EXTENDED_PLATFORM
570	depends on NUMA
571	depends on EFI
572	depends on KEXEC_CORE
573	depends on X86_X2APIC
574	depends on PCI
575	help
576	  This option is needed in order to support SGI Ultraviolet systems.
577	  If you don't have one of these, you should say N here.
578
579# Following is an alphabetically sorted list of 32 bit extended platforms
580# Please maintain the alphabetic order if and when there are additions
581
582config X86_GOLDFISH
583	bool "Goldfish (Virtual Platform)"
584	depends on X86_EXTENDED_PLATFORM
585	help
586	 Enable support for the Goldfish virtual platform used primarily
587	 for Android development. Unless you are building for the Android
588	 Goldfish emulator say N here.
589
590config X86_INTEL_CE
591	bool "CE4100 TV platform"
592	depends on PCI
593	depends on PCI_GODIRECT
594	depends on X86_IO_APIC
595	depends on X86_32
596	depends on X86_EXTENDED_PLATFORM
597	select X86_REBOOTFIXUPS
598	select OF
599	select OF_EARLY_FLATTREE
600	help
601	  Select for the Intel CE media processor (CE4100) SOC.
602	  This option compiles in support for the CE4100 SOC for settop
603	  boxes and media devices.
604
605config X86_INTEL_MID
606	bool "Intel MID platform support"
607	depends on X86_EXTENDED_PLATFORM
608	depends on X86_PLATFORM_DEVICES
609	depends on PCI
610	depends on X86_64 || (PCI_GOANY && X86_32)
611	depends on X86_IO_APIC
612	select I2C
613	select DW_APB_TIMER
614	select APB_TIMER
615	select INTEL_SCU_PCI
616	select MFD_INTEL_MSIC
617	help
618	  Select to build a kernel capable of supporting Intel MID (Mobile
619	  Internet Device) platform systems which do not have the PCI legacy
620	  interfaces. If you are building for a PC class system say N here.
621
622	  Intel MID platforms are based on an Intel processor and chipset which
623	  consume less power than most of the x86 derivatives.
624
625config X86_INTEL_QUARK
626	bool "Intel Quark platform support"
627	depends on X86_32
628	depends on X86_EXTENDED_PLATFORM
629	depends on X86_PLATFORM_DEVICES
630	depends on X86_TSC
631	depends on PCI
632	depends on PCI_GOANY
633	depends on X86_IO_APIC
634	select IOSF_MBI
635	select INTEL_IMR
636	select COMMON_CLK
637	help
638	  Select to include support for Quark X1000 SoC.
639	  Say Y here if you have a Quark based system such as the Arduino
640	  compatible Intel Galileo.
641
642config X86_INTEL_LPSS
643	bool "Intel Low Power Subsystem Support"
644	depends on X86 && ACPI && PCI
645	select COMMON_CLK
646	select PINCTRL
647	select IOSF_MBI
648	help
649	  Select to build support for Intel Low Power Subsystem such as
650	  found on Intel Lynxpoint PCH. Selecting this option enables
651	  things like clock tree (common clock framework) and pincontrol
652	  which are needed by the LPSS peripheral drivers.
653
654config X86_AMD_PLATFORM_DEVICE
655	bool "AMD ACPI2Platform devices support"
656	depends on ACPI
657	select COMMON_CLK
658	select PINCTRL
659	help
660	  Select to interpret AMD specific ACPI device to platform device
661	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
662	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
663	  implemented under PINCTRL subsystem.
664
665config IOSF_MBI
666	tristate "Intel SoC IOSF Sideband support for SoC platforms"
667	depends on PCI
668	help
669	  This option enables sideband register access support for Intel SoC
670	  platforms. On these platforms the IOSF sideband is used in lieu of
671	  MSR's for some register accesses, mostly but not limited to thermal
672	  and power. Drivers may query the availability of this device to
673	  determine if they need the sideband in order to work on these
674	  platforms. The sideband is available on the following SoC products.
675	  This list is not meant to be exclusive.
676	   - BayTrail
677	   - Braswell
678	   - Quark
679
680	  You should say Y if you are running a kernel on one of these SoC's.
681
682config IOSF_MBI_DEBUG
683	bool "Enable IOSF sideband access through debugfs"
684	depends on IOSF_MBI && DEBUG_FS
685	help
686	  Select this option to expose the IOSF sideband access registers (MCR,
687	  MDR, MCRX) through debugfs to write and read register information from
688	  different units on the SoC. This is most useful for obtaining device
689	  state information for debug and analysis. As this is a general access
690	  mechanism, users of this option would have specific knowledge of the
691	  device they want to access.
692
693	  If you don't require the option or are in doubt, say N.
694
695config X86_RDC321X
696	bool "RDC R-321x SoC"
697	depends on X86_32
698	depends on X86_EXTENDED_PLATFORM
699	select M486
700	select X86_REBOOTFIXUPS
701	help
702	  This option is needed for RDC R-321x system-on-chip, also known
703	  as R-8610-(G).
704	  If you don't have one of these chips, you should say N here.
705
706config X86_32_NON_STANDARD
707	bool "Support non-standard 32-bit SMP architectures"
708	depends on X86_32 && SMP
709	depends on X86_EXTENDED_PLATFORM
710	help
711	  This option compiles in the bigsmp and STA2X11 default
712	  subarchitectures.  It is intended for a generic binary
713	  kernel. If you select them all, kernel will probe it one by
714	  one and will fallback to default.
715
716# Alphabetically sorted list of Non standard 32 bit platforms
717
718config X86_SUPPORTS_MEMORY_FAILURE
719	def_bool y
720	# MCE code calls memory_failure():
721	depends on X86_MCE
722	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
723	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
724	depends on X86_64 || !SPARSEMEM
725	select ARCH_SUPPORTS_MEMORY_FAILURE
726
727config STA2X11
728	bool "STA2X11 Companion Chip Support"
729	depends on X86_32_NON_STANDARD && PCI
730	select SWIOTLB
731	select MFD_STA2X11
732	select GPIOLIB
733	help
734	  This adds support for boards based on the STA2X11 IO-Hub,
735	  a.k.a. "ConneXt". The chip is used in place of the standard
736	  PC chipset, so all "standard" peripherals are missing. If this
737	  option is selected the kernel will still be able to boot on
738	  standard PC machines.
739
740config X86_32_IRIS
741	tristate "Eurobraille/Iris poweroff module"
742	depends on X86_32
743	help
744	  The Iris machines from EuroBraille do not have APM or ACPI support
745	  to shut themselves down properly.  A special I/O sequence is
746	  needed to do so, which is what this module does at
747	  kernel shutdown.
748
749	  This is only for Iris machines from EuroBraille.
750
751	  If unused, say N.
752
753config SCHED_OMIT_FRAME_POINTER
754	def_bool y
755	prompt "Single-depth WCHAN output"
756	depends on X86
757	help
758	  Calculate simpler /proc/<PID>/wchan values. If this option
759	  is disabled then wchan values will recurse back to the
760	  caller function. This provides more accurate wchan values,
761	  at the expense of slightly more scheduling overhead.
762
763	  If in doubt, say "Y".
764
765menuconfig HYPERVISOR_GUEST
766	bool "Linux guest support"
767	help
768	  Say Y here to enable options for running Linux under various hyper-
769	  visors. This option enables basic hypervisor detection and platform
770	  setup.
771
772	  If you say N, all options in this submenu will be skipped and
773	  disabled, and Linux guest support won't be built in.
774
775if HYPERVISOR_GUEST
776
777config PARAVIRT
778	bool "Enable paravirtualization code"
779	depends on HAVE_STATIC_CALL
780	help
781	  This changes the kernel so it can modify itself when it is run
782	  under a hypervisor, potentially improving performance significantly
783	  over full virtualization.  However, when run without a hypervisor
784	  the kernel is theoretically slower and slightly larger.
785
786config PARAVIRT_XXL
787	bool
788
789config PARAVIRT_DEBUG
790	bool "paravirt-ops debugging"
791	depends on PARAVIRT && DEBUG_KERNEL
792	help
793	  Enable to debug paravirt_ops internals.  Specifically, BUG if
794	  a paravirt_op is missing when it is called.
795
796config PARAVIRT_SPINLOCKS
797	bool "Paravirtualization layer for spinlocks"
798	depends on PARAVIRT && SMP
799	help
800	  Paravirtualized spinlocks allow a pvops backend to replace the
801	  spinlock implementation with something virtualization-friendly
802	  (for example, block the virtual CPU rather than spinning).
803
804	  It has a minimal impact on native kernels and gives a nice performance
805	  benefit on paravirtualized KVM / Xen kernels.
806
807	  If you are unsure how to answer this question, answer Y.
808
809config X86_HV_CALLBACK_VECTOR
810	def_bool n
811
812source "arch/x86/xen/Kconfig"
813
814config KVM_GUEST
815	bool "KVM Guest support (including kvmclock)"
816	depends on PARAVIRT
817	select PARAVIRT_CLOCK
818	select ARCH_CPUIDLE_HALTPOLL
819	select X86_HV_CALLBACK_VECTOR
820	default y
821	help
822	  This option enables various optimizations for running under the KVM
823	  hypervisor. It includes a paravirtualized clock, so that instead
824	  of relying on a PIT (or probably other) emulation by the
825	  underlying device model, the host provides the guest with
826	  timing infrastructure such as time of day, and system time
827
828config ARCH_CPUIDLE_HALTPOLL
829	def_bool n
830	prompt "Disable host haltpoll when loading haltpoll driver"
831	help
832	  If virtualized under KVM, disable host haltpoll.
833
834config PVH
835	bool "Support for running PVH guests"
836	help
837	  This option enables the PVH entry point for guest virtual machines
838	  as specified in the x86/HVM direct boot ABI.
839
840config PARAVIRT_TIME_ACCOUNTING
841	bool "Paravirtual steal time accounting"
842	depends on PARAVIRT
843	help
844	  Select this option to enable fine granularity task steal time
845	  accounting. Time spent executing other tasks in parallel with
846	  the current vCPU is discounted from the vCPU power. To account for
847	  that, there can be a small performance impact.
848
849	  If in doubt, say N here.
850
851config PARAVIRT_CLOCK
852	bool
853
854config JAILHOUSE_GUEST
855	bool "Jailhouse non-root cell support"
856	depends on X86_64 && PCI
857	select X86_PM_TIMER
858	help
859	  This option allows to run Linux as guest in a Jailhouse non-root
860	  cell. You can leave this option disabled if you only want to start
861	  Jailhouse and run Linux afterwards in the root cell.
862
863config ACRN_GUEST
864	bool "ACRN Guest support"
865	depends on X86_64
866	select X86_HV_CALLBACK_VECTOR
867	help
868	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
869	  a flexible, lightweight reference open-source hypervisor, built with
870	  real-time and safety-criticality in mind. It is built for embedded
871	  IOT with small footprint and real-time features. More details can be
872	  found in https://projectacrn.org/.
873
874endif #HYPERVISOR_GUEST
875
876source "arch/x86/Kconfig.cpu"
877
878config HPET_TIMER
879	def_bool X86_64
880	prompt "HPET Timer Support" if X86_32
881	help
882	  Use the IA-PC HPET (High Precision Event Timer) to manage
883	  time in preference to the PIT and RTC, if a HPET is
884	  present.
885	  HPET is the next generation timer replacing legacy 8254s.
886	  The HPET provides a stable time base on SMP
887	  systems, unlike the TSC, but it is more expensive to access,
888	  as it is off-chip.  The interface used is documented
889	  in the HPET spec, revision 1.
890
891	  You can safely choose Y here.  However, HPET will only be
892	  activated if the platform and the BIOS support this feature.
893	  Otherwise the 8254 will be used for timing services.
894
895	  Choose N to continue using the legacy 8254 timer.
896
897config HPET_EMULATE_RTC
898	def_bool y
899	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
900
901# Mark as expert because too many people got it wrong.
902# The code disables itself when not needed.
903config DMI
904	default y
905	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
906	bool "Enable DMI scanning" if EXPERT
907	help
908	  Enabled scanning of DMI to identify machine quirks. Say Y
909	  here unless you have verified that your setup is not
910	  affected by entries in the DMI blacklist. Required by PNP
911	  BIOS code.
912
913config GART_IOMMU
914	bool "Old AMD GART IOMMU support"
915	select DMA_OPS
916	select IOMMU_HELPER
917	select SWIOTLB
918	depends on X86_64 && PCI && AMD_NB
919	help
920	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
921	  GART based hardware IOMMUs.
922
923	  The GART supports full DMA access for devices with 32-bit access
924	  limitations, on systems with more than 3 GB. This is usually needed
925	  for USB, sound, many IDE/SATA chipsets and some other devices.
926
927	  Newer systems typically have a modern AMD IOMMU, supported via
928	  the CONFIG_AMD_IOMMU=y config option.
929
930	  In normal configurations this driver is only active when needed:
931	  there's more than 3 GB of memory and the system contains a
932	  32-bit limited device.
933
934	  If unsure, say Y.
935
936config MAXSMP
937	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
938	depends on X86_64 && SMP && DEBUG_KERNEL
939	select CPUMASK_OFFSTACK
940	help
941	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
942	  If unsure, say N.
943
944#
945# The maximum number of CPUs supported:
946#
947# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
948# and which can be configured interactively in the
949# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
950#
951# The ranges are different on 32-bit and 64-bit kernels, depending on
952# hardware capabilities and scalability features of the kernel.
953#
954# ( If MAXSMP is enabled we just use the highest possible value and disable
955#   interactive configuration. )
956#
957
958config NR_CPUS_RANGE_BEGIN
959	int
960	default NR_CPUS_RANGE_END if MAXSMP
961	default    1 if !SMP
962	default    2
963
964config NR_CPUS_RANGE_END
965	int
966	depends on X86_32
967	default   64 if  SMP &&  X86_BIGSMP
968	default    8 if  SMP && !X86_BIGSMP
969	default    1 if !SMP
970
971config NR_CPUS_RANGE_END
972	int
973	depends on X86_64
974	default 8192 if  SMP && CPUMASK_OFFSTACK
975	default  512 if  SMP && !CPUMASK_OFFSTACK
976	default    1 if !SMP
977
978config NR_CPUS_DEFAULT
979	int
980	depends on X86_32
981	default   32 if  X86_BIGSMP
982	default    8 if  SMP
983	default    1 if !SMP
984
985config NR_CPUS_DEFAULT
986	int
987	depends on X86_64
988	default 8192 if  MAXSMP
989	default   64 if  SMP
990	default    1 if !SMP
991
992config NR_CPUS
993	int "Maximum number of CPUs" if SMP && !MAXSMP
994	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
995	default NR_CPUS_DEFAULT
996	help
997	  This allows you to specify the maximum number of CPUs which this
998	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
999	  supported value is 8192, otherwise the maximum value is 512.  The
1000	  minimum value which makes sense is 2.
1001
1002	  This is purely to save memory: each supported CPU adds about 8KB
1003	  to the kernel image.
1004
1005config SCHED_SMT
1006	def_bool y if SMP
1007
1008config SCHED_MC
1009	def_bool y
1010	prompt "Multi-core scheduler support"
1011	depends on SMP
1012	help
1013	  Multi-core scheduler support improves the CPU scheduler's decision
1014	  making when dealing with multi-core CPU chips at a cost of slightly
1015	  increased overhead in some places. If unsure say N here.
1016
1017config SCHED_MC_PRIO
1018	bool "CPU core priorities scheduler support"
1019	depends on SCHED_MC && CPU_SUP_INTEL
1020	select X86_INTEL_PSTATE
1021	select CPU_FREQ
1022	default y
1023	help
1024	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1025	  core ordering determined at manufacturing time, which allows
1026	  certain cores to reach higher turbo frequencies (when running
1027	  single threaded workloads) than others.
1028
1029	  Enabling this kernel feature teaches the scheduler about
1030	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1031	  scheduler's CPU selection logic accordingly, so that higher
1032	  overall system performance can be achieved.
1033
1034	  This feature will have no effect on CPUs without this feature.
1035
1036	  If unsure say Y here.
1037
1038config UP_LATE_INIT
1039	def_bool y
1040	depends on !SMP && X86_LOCAL_APIC
1041
1042config X86_UP_APIC
1043	bool "Local APIC support on uniprocessors" if !PCI_MSI
1044	default PCI_MSI
1045	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1046	help
1047	  A local APIC (Advanced Programmable Interrupt Controller) is an
1048	  integrated interrupt controller in the CPU. If you have a single-CPU
1049	  system which has a processor with a local APIC, you can say Y here to
1050	  enable and use it. If you say Y here even though your machine doesn't
1051	  have a local APIC, then the kernel will still run with no slowdown at
1052	  all. The local APIC supports CPU-generated self-interrupts (timer,
1053	  performance counters), and the NMI watchdog which detects hard
1054	  lockups.
1055
1056config X86_UP_IOAPIC
1057	bool "IO-APIC support on uniprocessors"
1058	depends on X86_UP_APIC
1059	help
1060	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1061	  SMP-capable replacement for PC-style interrupt controllers. Most
1062	  SMP systems and many recent uniprocessor systems have one.
1063
1064	  If you have a single-CPU system with an IO-APIC, you can say Y here
1065	  to use it. If you say Y here even though your machine doesn't have
1066	  an IO-APIC, then the kernel will still run with no slowdown at all.
1067
1068config X86_LOCAL_APIC
1069	def_bool y
1070	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1071	select IRQ_DOMAIN_HIERARCHY
1072	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
1073
1074config X86_IO_APIC
1075	def_bool y
1076	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1077
1078config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1079	bool "Reroute for broken boot IRQs"
1080	depends on X86_IO_APIC
1081	help
1082	  This option enables a workaround that fixes a source of
1083	  spurious interrupts. This is recommended when threaded
1084	  interrupt handling is used on systems where the generation of
1085	  superfluous "boot interrupts" cannot be disabled.
1086
1087	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1088	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1089	  kernel does during interrupt handling). On chipsets where this
1090	  boot IRQ generation cannot be disabled, this workaround keeps
1091	  the original IRQ line masked so that only the equivalent "boot
1092	  IRQ" is delivered to the CPUs. The workaround also tells the
1093	  kernel to set up the IRQ handler on the boot IRQ line. In this
1094	  way only one interrupt is delivered to the kernel. Otherwise
1095	  the spurious second interrupt may cause the kernel to bring
1096	  down (vital) interrupt lines.
1097
1098	  Only affects "broken" chipsets. Interrupt sharing may be
1099	  increased on these systems.
1100
1101config X86_MCE
1102	bool "Machine Check / overheating reporting"
1103	select GENERIC_ALLOCATOR
1104	default y
1105	help
1106	  Machine Check support allows the processor to notify the
1107	  kernel if it detects a problem (e.g. overheating, data corruption).
1108	  The action the kernel takes depends on the severity of the problem,
1109	  ranging from warning messages to halting the machine.
1110
1111config X86_MCELOG_LEGACY
1112	bool "Support for deprecated /dev/mcelog character device"
1113	depends on X86_MCE
1114	help
1115	  Enable support for /dev/mcelog which is needed by the old mcelog
1116	  userspace logging daemon. Consider switching to the new generation
1117	  rasdaemon solution.
1118
1119config X86_MCE_INTEL
1120	def_bool y
1121	prompt "Intel MCE features"
1122	depends on X86_MCE && X86_LOCAL_APIC
1123	help
1124	   Additional support for intel specific MCE features such as
1125	   the thermal monitor.
1126
1127config X86_MCE_AMD
1128	def_bool y
1129	prompt "AMD MCE features"
1130	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1131	help
1132	   Additional support for AMD specific MCE features such as
1133	   the DRAM Error Threshold.
1134
1135config X86_ANCIENT_MCE
1136	bool "Support for old Pentium 5 / WinChip machine checks"
1137	depends on X86_32 && X86_MCE
1138	help
1139	  Include support for machine check handling on old Pentium 5 or WinChip
1140	  systems. These typically need to be enabled explicitly on the command
1141	  line.
1142
1143config X86_MCE_THRESHOLD
1144	depends on X86_MCE_AMD || X86_MCE_INTEL
1145	def_bool y
1146
1147config X86_MCE_INJECT
1148	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1149	tristate "Machine check injector support"
1150	help
1151	  Provide support for injecting machine checks for testing purposes.
1152	  If you don't know what a machine check is and you don't do kernel
1153	  QA it is safe to say n.
1154
1155source "arch/x86/events/Kconfig"
1156
1157config X86_LEGACY_VM86
1158	bool "Legacy VM86 support"
1159	depends on X86_32
1160	help
1161	  This option allows user programs to put the CPU into V8086
1162	  mode, which is an 80286-era approximation of 16-bit real mode.
1163
1164	  Some very old versions of X and/or vbetool require this option
1165	  for user mode setting.  Similarly, DOSEMU will use it if
1166	  available to accelerate real mode DOS programs.  However, any
1167	  recent version of DOSEMU, X, or vbetool should be fully
1168	  functional even without kernel VM86 support, as they will all
1169	  fall back to software emulation. Nevertheless, if you are using
1170	  a 16-bit DOS program where 16-bit performance matters, vm86
1171	  mode might be faster than emulation and you might want to
1172	  enable this option.
1173
1174	  Note that any app that works on a 64-bit kernel is unlikely to
1175	  need this option, as 64-bit kernels don't, and can't, support
1176	  V8086 mode. This option is also unrelated to 16-bit protected
1177	  mode and is not needed to run most 16-bit programs under Wine.
1178
1179	  Enabling this option increases the complexity of the kernel
1180	  and slows down exception handling a tiny bit.
1181
1182	  If unsure, say N here.
1183
1184config VM86
1185	bool
1186	default X86_LEGACY_VM86
1187
1188config X86_16BIT
1189	bool "Enable support for 16-bit segments" if EXPERT
1190	default y
1191	depends on MODIFY_LDT_SYSCALL
1192	help
1193	  This option is required by programs like Wine to run 16-bit
1194	  protected mode legacy code on x86 processors.  Disabling
1195	  this option saves about 300 bytes on i386, or around 6K text
1196	  plus 16K runtime memory on x86-64,
1197
1198config X86_ESPFIX32
1199	def_bool y
1200	depends on X86_16BIT && X86_32
1201
1202config X86_ESPFIX64
1203	def_bool y
1204	depends on X86_16BIT && X86_64
1205
1206config X86_VSYSCALL_EMULATION
1207	bool "Enable vsyscall emulation" if EXPERT
1208	default y
1209	depends on X86_64
1210	help
1211	 This enables emulation of the legacy vsyscall page.  Disabling
1212	 it is roughly equivalent to booting with vsyscall=none, except
1213	 that it will also disable the helpful warning if a program
1214	 tries to use a vsyscall.  With this option set to N, offending
1215	 programs will just segfault, citing addresses of the form
1216	 0xffffffffff600?00.
1217
1218	 This option is required by many programs built before 2013, and
1219	 care should be used even with newer programs if set to N.
1220
1221	 Disabling this option saves about 7K of kernel size and
1222	 possibly 4K of additional runtime pagetable memory.
1223
1224config X86_IOPL_IOPERM
1225	bool "IOPERM and IOPL Emulation"
1226	default y
1227	help
1228	  This enables the ioperm() and iopl() syscalls which are necessary
1229	  for legacy applications.
1230
1231	  Legacy IOPL support is an overbroad mechanism which allows user
1232	  space aside of accessing all 65536 I/O ports also to disable
1233	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1234	  capabilities and permission from potentially active security
1235	  modules.
1236
1237	  The emulation restricts the functionality of the syscall to
1238	  only allowing the full range I/O port access, but prevents the
1239	  ability to disable interrupts from user space which would be
1240	  granted if the hardware IOPL mechanism would be used.
1241
1242config TOSHIBA
1243	tristate "Toshiba Laptop support"
1244	depends on X86_32
1245	help
1246	  This adds a driver to safely access the System Management Mode of
1247	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1248	  not work on models with a Phoenix BIOS. The System Management Mode
1249	  is used to set the BIOS and power saving options on Toshiba portables.
1250
1251	  For information on utilities to make use of this driver see the
1252	  Toshiba Linux utilities web site at:
1253	  <http://www.buzzard.org.uk/toshiba/>.
1254
1255	  Say Y if you intend to run this kernel on a Toshiba portable.
1256	  Say N otherwise.
1257
1258config I8K
1259	tristate "Dell i8k legacy laptop support"
1260	select HWMON
1261	select SENSORS_DELL_SMM
1262	help
1263	  This option enables legacy /proc/i8k userspace interface in hwmon
1264	  dell-smm-hwmon driver. Character file /proc/i8k reports bios version,
1265	  temperature and allows controlling fan speeds of Dell laptops via
1266	  System Management Mode. For old Dell laptops (like Dell Inspiron 8000)
1267	  it reports also power and hotkey status. For fan speed control is
1268	  needed userspace package i8kutils.
1269
1270	  Say Y if you intend to run this kernel on old Dell laptops or want to
1271	  use userspace package i8kutils.
1272	  Say N otherwise.
1273
1274config X86_REBOOTFIXUPS
1275	bool "Enable X86 board specific fixups for reboot"
1276	depends on X86_32
1277	help
1278	  This enables chipset and/or board specific fixups to be done
1279	  in order to get reboot to work correctly. This is only needed on
1280	  some combinations of hardware and BIOS. The symptom, for which
1281	  this config is intended, is when reboot ends with a stalled/hung
1282	  system.
1283
1284	  Currently, the only fixup is for the Geode machines using
1285	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1286
1287	  Say Y if you want to enable the fixup. Currently, it's safe to
1288	  enable this option even if you don't need it.
1289	  Say N otherwise.
1290
1291config MICROCODE
1292	bool "CPU microcode loading support"
1293	default y
1294	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1295	help
1296	  If you say Y here, you will be able to update the microcode on
1297	  Intel and AMD processors. The Intel support is for the IA32 family,
1298	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1299	  AMD support is for families 0x10 and later. You will obviously need
1300	  the actual microcode binary data itself which is not shipped with
1301	  the Linux kernel.
1302
1303	  The preferred method to load microcode from a detached initrd is described
1304	  in Documentation/x86/microcode.rst. For that you need to enable
1305	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1306	  initrd for microcode blobs.
1307
1308	  In addition, you can build the microcode into the kernel. For that you
1309	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1310	  config option.
1311
1312config MICROCODE_INTEL
1313	bool "Intel microcode loading support"
1314	depends on MICROCODE
1315	default MICROCODE
1316	help
1317	  This options enables microcode patch loading support for Intel
1318	  processors.
1319
1320	  For the current Intel microcode data package go to
1321	  <https://downloadcenter.intel.com> and search for
1322	  'Linux Processor Microcode Data File'.
1323
1324config MICROCODE_AMD
1325	bool "AMD microcode loading support"
1326	depends on MICROCODE
1327	help
1328	  If you select this option, microcode patch loading support for AMD
1329	  processors will be enabled.
1330
1331config MICROCODE_OLD_INTERFACE
1332	bool "Ancient loading interface (DEPRECATED)"
1333	default n
1334	depends on MICROCODE
1335	help
1336	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
1337	  which was used by userspace tools like iucode_tool and microcode.ctl.
1338	  It is inadequate because it runs too late to be able to properly
1339	  load microcode on a machine and it needs special tools. Instead, you
1340	  should've switched to the early loading method with the initrd or
1341	  builtin microcode by now: Documentation/x86/microcode.rst
1342
1343config X86_MSR
1344	tristate "/dev/cpu/*/msr - Model-specific register support"
1345	help
1346	  This device gives privileged processes access to the x86
1347	  Model-Specific Registers (MSRs).  It is a character device with
1348	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1349	  MSR accesses are directed to a specific CPU on multi-processor
1350	  systems.
1351
1352config X86_CPUID
1353	tristate "/dev/cpu/*/cpuid - CPU information support"
1354	help
1355	  This device gives processes access to the x86 CPUID instruction to
1356	  be executed on a specific processor.  It is a character device
1357	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1358	  /dev/cpu/31/cpuid.
1359
1360choice
1361	prompt "High Memory Support"
1362	default HIGHMEM4G
1363	depends on X86_32
1364
1365config NOHIGHMEM
1366	bool "off"
1367	help
1368	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1369	  However, the address space of 32-bit x86 processors is only 4
1370	  Gigabytes large. That means that, if you have a large amount of
1371	  physical memory, not all of it can be "permanently mapped" by the
1372	  kernel. The physical memory that's not permanently mapped is called
1373	  "high memory".
1374
1375	  If you are compiling a kernel which will never run on a machine with
1376	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1377	  choice and suitable for most users). This will result in a "3GB/1GB"
1378	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1379	  space and the remaining part of the 4GB virtual memory space is used
1380	  by the kernel to permanently map as much physical memory as
1381	  possible.
1382
1383	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1384	  answer "4GB" here.
1385
1386	  If more than 4 Gigabytes is used then answer "64GB" here. This
1387	  selection turns Intel PAE (Physical Address Extension) mode on.
1388	  PAE implements 3-level paging on IA32 processors. PAE is fully
1389	  supported by Linux, PAE mode is implemented on all recent Intel
1390	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1391	  then the kernel will not boot on CPUs that don't support PAE!
1392
1393	  The actual amount of total physical memory will either be
1394	  auto detected or can be forced by using a kernel command line option
1395	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1396	  your boot loader (lilo or loadlin) about how to pass options to the
1397	  kernel at boot time.)
1398
1399	  If unsure, say "off".
1400
1401config HIGHMEM4G
1402	bool "4GB"
1403	help
1404	  Select this if you have a 32-bit processor and between 1 and 4
1405	  gigabytes of physical RAM.
1406
1407config HIGHMEM64G
1408	bool "64GB"
1409	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !WINCHIP3D && !MK6
1410	select X86_PAE
1411	help
1412	  Select this if you have a 32-bit processor and more than 4
1413	  gigabytes of physical RAM.
1414
1415endchoice
1416
1417choice
1418	prompt "Memory split" if EXPERT
1419	default VMSPLIT_3G
1420	depends on X86_32
1421	help
1422	  Select the desired split between kernel and user memory.
1423
1424	  If the address range available to the kernel is less than the
1425	  physical memory installed, the remaining memory will be available
1426	  as "high memory". Accessing high memory is a little more costly
1427	  than low memory, as it needs to be mapped into the kernel first.
1428	  Note that increasing the kernel address space limits the range
1429	  available to user programs, making the address space there
1430	  tighter.  Selecting anything other than the default 3G/1G split
1431	  will also likely make your kernel incompatible with binary-only
1432	  kernel modules.
1433
1434	  If you are not absolutely sure what you are doing, leave this
1435	  option alone!
1436
1437	config VMSPLIT_3G
1438		bool "3G/1G user/kernel split"
1439	config VMSPLIT_3G_OPT
1440		depends on !X86_PAE
1441		bool "3G/1G user/kernel split (for full 1G low memory)"
1442	config VMSPLIT_2G
1443		bool "2G/2G user/kernel split"
1444	config VMSPLIT_2G_OPT
1445		depends on !X86_PAE
1446		bool "2G/2G user/kernel split (for full 2G low memory)"
1447	config VMSPLIT_1G
1448		bool "1G/3G user/kernel split"
1449endchoice
1450
1451config PAGE_OFFSET
1452	hex
1453	default 0xB0000000 if VMSPLIT_3G_OPT
1454	default 0x80000000 if VMSPLIT_2G
1455	default 0x78000000 if VMSPLIT_2G_OPT
1456	default 0x40000000 if VMSPLIT_1G
1457	default 0xC0000000
1458	depends on X86_32
1459
1460config HIGHMEM
1461	def_bool y
1462	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1463
1464config X86_PAE
1465	bool "PAE (Physical Address Extension) Support"
1466	depends on X86_32 && !HIGHMEM4G
1467	select PHYS_ADDR_T_64BIT
1468	select SWIOTLB
1469	help
1470	  PAE is required for NX support, and furthermore enables
1471	  larger swapspace support for non-overcommit purposes. It
1472	  has the cost of more pagetable lookup overhead, and also
1473	  consumes more pagetable space per process.
1474
1475config X86_5LEVEL
1476	bool "Enable 5-level page tables support"
1477	default y
1478	select DYNAMIC_MEMORY_LAYOUT
1479	select SPARSEMEM_VMEMMAP
1480	depends on X86_64
1481	help
1482	  5-level paging enables access to larger address space:
1483	  upto 128 PiB of virtual address space and 4 PiB of
1484	  physical address space.
1485
1486	  It will be supported by future Intel CPUs.
1487
1488	  A kernel with the option enabled can be booted on machines that
1489	  support 4- or 5-level paging.
1490
1491	  See Documentation/x86/x86_64/5level-paging.rst for more
1492	  information.
1493
1494	  Say N if unsure.
1495
1496config X86_DIRECT_GBPAGES
1497	def_bool y
1498	depends on X86_64
1499	help
1500	  Certain kernel features effectively disable kernel
1501	  linear 1 GB mappings (even if the CPU otherwise
1502	  supports them), so don't confuse the user by printing
1503	  that we have them enabled.
1504
1505config X86_CPA_STATISTICS
1506	bool "Enable statistic for Change Page Attribute"
1507	depends on DEBUG_FS
1508	help
1509	  Expose statistics about the Change Page Attribute mechanism, which
1510	  helps to determine the effectiveness of preserving large and huge
1511	  page mappings when mapping protections are changed.
1512
1513config AMD_MEM_ENCRYPT
1514	bool "AMD Secure Memory Encryption (SME) support"
1515	depends on X86_64 && CPU_SUP_AMD
1516	select DMA_COHERENT_POOL
1517	select DYNAMIC_PHYSICAL_MASK
1518	select ARCH_USE_MEMREMAP_PROT
1519	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1520	select INSTRUCTION_DECODER
1521	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
1522	help
1523	  Say yes to enable support for the encryption of system memory.
1524	  This requires an AMD processor that supports Secure Memory
1525	  Encryption (SME).
1526
1527config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1528	bool "Activate AMD Secure Memory Encryption (SME) by default"
1529	default y
1530	depends on AMD_MEM_ENCRYPT
1531	help
1532	  Say yes to have system memory encrypted by default if running on
1533	  an AMD processor that supports Secure Memory Encryption (SME).
1534
1535	  If set to Y, then the encryption of system memory can be
1536	  deactivated with the mem_encrypt=off command line option.
1537
1538	  If set to N, then the encryption of system memory can be
1539	  activated with the mem_encrypt=on command line option.
1540
1541# Common NUMA Features
1542config NUMA
1543	bool "NUMA Memory Allocation and Scheduler Support"
1544	depends on SMP
1545	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1546	default y if X86_BIGSMP
1547	help
1548	  Enable NUMA (Non-Uniform Memory Access) support.
1549
1550	  The kernel will try to allocate memory used by a CPU on the
1551	  local memory controller of the CPU and add some more
1552	  NUMA awareness to the kernel.
1553
1554	  For 64-bit this is recommended if the system is Intel Core i7
1555	  (or later), AMD Opteron, or EM64T NUMA.
1556
1557	  For 32-bit this is only needed if you boot a 32-bit
1558	  kernel on a 64-bit NUMA platform.
1559
1560	  Otherwise, you should say N.
1561
1562config AMD_NUMA
1563	def_bool y
1564	prompt "Old style AMD Opteron NUMA detection"
1565	depends on X86_64 && NUMA && PCI
1566	help
1567	  Enable AMD NUMA node topology detection.  You should say Y here if
1568	  you have a multi processor AMD system. This uses an old method to
1569	  read the NUMA configuration directly from the builtin Northbridge
1570	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1571	  which also takes priority if both are compiled in.
1572
1573config X86_64_ACPI_NUMA
1574	def_bool y
1575	prompt "ACPI NUMA detection"
1576	depends on X86_64 && NUMA && ACPI && PCI
1577	select ACPI_NUMA
1578	help
1579	  Enable ACPI SRAT based node topology detection.
1580
1581config NUMA_EMU
1582	bool "NUMA emulation"
1583	depends on NUMA
1584	help
1585	  Enable NUMA emulation. A flat machine will be split
1586	  into virtual nodes when booted with "numa=fake=N", where N is the
1587	  number of nodes. This is only useful for debugging.
1588
1589config NODES_SHIFT
1590	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1591	range 1 10
1592	default "10" if MAXSMP
1593	default "6" if X86_64
1594	default "3"
1595	depends on NEED_MULTIPLE_NODES
1596	help
1597	  Specify the maximum number of NUMA Nodes available on the target
1598	  system.  Increases memory reserved to accommodate various tables.
1599
1600config ARCH_FLATMEM_ENABLE
1601	def_bool y
1602	depends on X86_32 && !NUMA
1603
1604config ARCH_SPARSEMEM_ENABLE
1605	def_bool y
1606	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1607	select SPARSEMEM_STATIC if X86_32
1608	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1609
1610config ARCH_SPARSEMEM_DEFAULT
1611	def_bool X86_64 || (NUMA && X86_32)
1612
1613config ARCH_SELECT_MEMORY_MODEL
1614	def_bool y
1615	depends on ARCH_SPARSEMEM_ENABLE
1616
1617config ARCH_MEMORY_PROBE
1618	bool "Enable sysfs memory/probe interface"
1619	depends on X86_64 && MEMORY_HOTPLUG
1620	help
1621	  This option enables a sysfs memory/probe interface for testing.
1622	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1623	  If you are unsure how to answer this question, answer N.
1624
1625config ARCH_PROC_KCORE_TEXT
1626	def_bool y
1627	depends on X86_64 && PROC_KCORE
1628
1629config ILLEGAL_POINTER_VALUE
1630	hex
1631	default 0 if X86_32
1632	default 0xdead000000000000 if X86_64
1633
1634config X86_PMEM_LEGACY_DEVICE
1635	bool
1636
1637config X86_PMEM_LEGACY
1638	tristate "Support non-standard NVDIMMs and ADR protected memory"
1639	depends on PHYS_ADDR_T_64BIT
1640	depends on BLK_DEV
1641	select X86_PMEM_LEGACY_DEVICE
1642	select NUMA_KEEP_MEMINFO if NUMA
1643	select LIBNVDIMM
1644	help
1645	  Treat memory marked using the non-standard e820 type of 12 as used
1646	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1647	  The kernel will offer these regions to the 'pmem' driver so
1648	  they can be used for persistent storage.
1649
1650	  Say Y if unsure.
1651
1652config HIGHPTE
1653	bool "Allocate 3rd-level pagetables from highmem"
1654	depends on HIGHMEM
1655	help
1656	  The VM uses one page table entry for each page of physical memory.
1657	  For systems with a lot of RAM, this can be wasteful of precious
1658	  low memory.  Setting this option will put user-space page table
1659	  entries in high memory.
1660
1661config X86_CHECK_BIOS_CORRUPTION
1662	bool "Check for low memory corruption"
1663	help
1664	  Periodically check for memory corruption in low memory, which
1665	  is suspected to be caused by BIOS.  Even when enabled in the
1666	  configuration, it is disabled at runtime.  Enable it by
1667	  setting "memory_corruption_check=1" on the kernel command
1668	  line.  By default it scans the low 64k of memory every 60
1669	  seconds; see the memory_corruption_check_size and
1670	  memory_corruption_check_period parameters in
1671	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1672
1673	  When enabled with the default parameters, this option has
1674	  almost no overhead, as it reserves a relatively small amount
1675	  of memory and scans it infrequently.  It both detects corruption
1676	  and prevents it from affecting the running system.
1677
1678	  It is, however, intended as a diagnostic tool; if repeatable
1679	  BIOS-originated corruption always affects the same memory,
1680	  you can use memmap= to prevent the kernel from using that
1681	  memory.
1682
1683config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1684	bool "Set the default setting of memory_corruption_check"
1685	depends on X86_CHECK_BIOS_CORRUPTION
1686	default y
1687	help
1688	  Set whether the default state of memory_corruption_check is
1689	  on or off.
1690
1691config X86_RESERVE_LOW
1692	int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1693	default 64
1694	range 4 640
1695	help
1696	  Specify the amount of low memory to reserve for the BIOS.
1697
1698	  The first page contains BIOS data structures that the kernel
1699	  must not use, so that page must always be reserved.
1700
1701	  By default we reserve the first 64K of physical RAM, as a
1702	  number of BIOSes are known to corrupt that memory range
1703	  during events such as suspend/resume or monitor cable
1704	  insertion, so it must not be used by the kernel.
1705
1706	  You can set this to 4 if you are absolutely sure that you
1707	  trust the BIOS to get all its memory reservations and usages
1708	  right.  If you know your BIOS have problems beyond the
1709	  default 64K area, you can set this to 640 to avoid using the
1710	  entire low memory range.
1711
1712	  If you have doubts about the BIOS (e.g. suspend/resume does
1713	  not work or there's kernel crashes after certain hardware
1714	  hotplug events) then you might want to enable
1715	  X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1716	  typical corruption patterns.
1717
1718	  Leave this to the default value of 64 if you are unsure.
1719
1720config MATH_EMULATION
1721	bool
1722	depends on MODIFY_LDT_SYSCALL
1723	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1724	help
1725	  Linux can emulate a math coprocessor (used for floating point
1726	  operations) if you don't have one. 486DX and Pentium processors have
1727	  a math coprocessor built in, 486SX and 386 do not, unless you added
1728	  a 487DX or 387, respectively. (The messages during boot time can
1729	  give you some hints here ["man dmesg"].) Everyone needs either a
1730	  coprocessor or this emulation.
1731
1732	  If you don't have a math coprocessor, you need to say Y here; if you
1733	  say Y here even though you have a coprocessor, the coprocessor will
1734	  be used nevertheless. (This behavior can be changed with the kernel
1735	  command line option "no387", which comes handy if your coprocessor
1736	  is broken. Try "man bootparam" or see the documentation of your boot
1737	  loader (lilo or loadlin) about how to pass options to the kernel at
1738	  boot time.) This means that it is a good idea to say Y here if you
1739	  intend to use this kernel on different machines.
1740
1741	  More information about the internals of the Linux math coprocessor
1742	  emulation can be found in <file:arch/x86/math-emu/README>.
1743
1744	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1745	  kernel, it won't hurt.
1746
1747config MTRR
1748	def_bool y
1749	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1750	help
1751	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1752	  the Memory Type Range Registers (MTRRs) may be used to control
1753	  processor access to memory ranges. This is most useful if you have
1754	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1755	  allows bus write transfers to be combined into a larger transfer
1756	  before bursting over the PCI/AGP bus. This can increase performance
1757	  of image write operations 2.5 times or more. Saying Y here creates a
1758	  /proc/mtrr file which may be used to manipulate your processor's
1759	  MTRRs. Typically the X server should use this.
1760
1761	  This code has a reasonably generic interface so that similar
1762	  control registers on other processors can be easily supported
1763	  as well:
1764
1765	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1766	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1767	  these, the ARRs are used to emulate the MTRRs.
1768	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1769	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1770	  write-combining. All of these processors are supported by this code
1771	  and it makes sense to say Y here if you have one of them.
1772
1773	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1774	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1775	  can lead to all sorts of problems, so it's good to say Y here.
1776
1777	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1778	  just add about 9 KB to your kernel.
1779
1780	  See <file:Documentation/x86/mtrr.rst> for more information.
1781
1782config MTRR_SANITIZER
1783	def_bool y
1784	prompt "MTRR cleanup support"
1785	depends on MTRR
1786	help
1787	  Convert MTRR layout from continuous to discrete, so X drivers can
1788	  add writeback entries.
1789
1790	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1791	  The largest mtrr entry size for a continuous block can be set with
1792	  mtrr_chunk_size.
1793
1794	  If unsure, say Y.
1795
1796config MTRR_SANITIZER_ENABLE_DEFAULT
1797	int "MTRR cleanup enable value (0-1)"
1798	range 0 1
1799	default "0"
1800	depends on MTRR_SANITIZER
1801	help
1802	  Enable mtrr cleanup default value
1803
1804config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1805	int "MTRR cleanup spare reg num (0-7)"
1806	range 0 7
1807	default "1"
1808	depends on MTRR_SANITIZER
1809	help
1810	  mtrr cleanup spare entries default, it can be changed via
1811	  mtrr_spare_reg_nr=N on the kernel command line.
1812
1813config X86_PAT
1814	def_bool y
1815	prompt "x86 PAT support" if EXPERT
1816	depends on MTRR
1817	help
1818	  Use PAT attributes to setup page level cache control.
1819
1820	  PATs are the modern equivalents of MTRRs and are much more
1821	  flexible than MTRRs.
1822
1823	  Say N here if you see bootup problems (boot crash, boot hang,
1824	  spontaneous reboots) or a non-working video driver.
1825
1826	  If unsure, say Y.
1827
1828config ARCH_USES_PG_UNCACHED
1829	def_bool y
1830	depends on X86_PAT
1831
1832config ARCH_RANDOM
1833	def_bool y
1834	prompt "x86 architectural random number generator" if EXPERT
1835	help
1836	  Enable the x86 architectural RDRAND instruction
1837	  (Intel Bull Mountain technology) to generate random numbers.
1838	  If supported, this is a high bandwidth, cryptographically
1839	  secure hardware random number generator.
1840
1841config X86_SMAP
1842	def_bool y
1843	prompt "Supervisor Mode Access Prevention" if EXPERT
1844	help
1845	  Supervisor Mode Access Prevention (SMAP) is a security
1846	  feature in newer Intel processors.  There is a small
1847	  performance cost if this enabled and turned on; there is
1848	  also a small increase in the kernel size if this is enabled.
1849
1850	  If unsure, say Y.
1851
1852config X86_UMIP
1853	def_bool y
1854	prompt "User Mode Instruction Prevention" if EXPERT
1855	help
1856	  User Mode Instruction Prevention (UMIP) is a security feature in
1857	  some x86 processors. If enabled, a general protection fault is
1858	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1859	  executed in user mode. These instructions unnecessarily expose
1860	  information about the hardware state.
1861
1862	  The vast majority of applications do not use these instructions.
1863	  For the very few that do, software emulation is provided in
1864	  specific cases in protected and virtual-8086 modes. Emulated
1865	  results are dummy.
1866
1867config X86_INTEL_MEMORY_PROTECTION_KEYS
1868	prompt "Memory Protection Keys"
1869	def_bool y
1870	# Note: only available in 64-bit mode
1871	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1872	select ARCH_USES_HIGH_VMA_FLAGS
1873	select ARCH_HAS_PKEYS
1874	help
1875	  Memory Protection Keys provides a mechanism for enforcing
1876	  page-based protections, but without requiring modification of the
1877	  page tables when an application changes protection domains.
1878
1879	  For details, see Documentation/core-api/protection-keys.rst
1880
1881	  If unsure, say y.
1882
1883choice
1884	prompt "TSX enable mode"
1885	depends on CPU_SUP_INTEL
1886	default X86_INTEL_TSX_MODE_OFF
1887	help
1888	  Intel's TSX (Transactional Synchronization Extensions) feature
1889	  allows to optimize locking protocols through lock elision which
1890	  can lead to a noticeable performance boost.
1891
1892	  On the other hand it has been shown that TSX can be exploited
1893	  to form side channel attacks (e.g. TAA) and chances are there
1894	  will be more of those attacks discovered in the future.
1895
1896	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1897	  might override this decision by tsx=on the command line parameter.
1898	  Even with TSX enabled, the kernel will attempt to enable the best
1899	  possible TAA mitigation setting depending on the microcode available
1900	  for the particular machine.
1901
1902	  This option allows to set the default tsx mode between tsx=on, =off
1903	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1904	  details.
1905
1906	  Say off if not sure, auto if TSX is in use but it should be used on safe
1907	  platforms or on if TSX is in use and the security aspect of tsx is not
1908	  relevant.
1909
1910config X86_INTEL_TSX_MODE_OFF
1911	bool "off"
1912	help
1913	  TSX is disabled if possible - equals to tsx=off command line parameter.
1914
1915config X86_INTEL_TSX_MODE_ON
1916	bool "on"
1917	help
1918	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1919	  line parameter.
1920
1921config X86_INTEL_TSX_MODE_AUTO
1922	bool "auto"
1923	help
1924	  TSX is enabled on TSX capable HW that is believed to be safe against
1925	  side channel attacks- equals the tsx=auto command line parameter.
1926endchoice
1927
1928config X86_SGX
1929	bool "Software Guard eXtensions (SGX)"
1930	depends on X86_64 && CPU_SUP_INTEL
1931	depends on CRYPTO=y
1932	depends on CRYPTO_SHA256=y
1933	select SRCU
1934	select MMU_NOTIFIER
1935	select NUMA_KEEP_MEMINFO if NUMA
1936	help
1937	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1938	  that can be used by applications to set aside private regions of code
1939	  and data, referred to as enclaves. An enclave's private memory can
1940	  only be accessed by code running within the enclave. Accesses from
1941	  outside the enclave, including other enclaves, are disallowed by
1942	  hardware.
1943
1944	  If unsure, say N.
1945
1946config EFI
1947	bool "EFI runtime service support"
1948	depends on ACPI
1949	select UCS2_STRING
1950	select EFI_RUNTIME_WRAPPERS
1951	help
1952	  This enables the kernel to use EFI runtime services that are
1953	  available (such as the EFI variable services).
1954
1955	  This option is only useful on systems that have EFI firmware.
1956	  In addition, you should use the latest ELILO loader available
1957	  at <http://elilo.sourceforge.net> in order to take advantage
1958	  of EFI runtime services. However, even with this option, the
1959	  resultant kernel should continue to boot on existing non-EFI
1960	  platforms.
1961
1962config EFI_STUB
1963	bool "EFI stub support"
1964	depends on EFI && !X86_USE_3DNOW
1965	depends on $(cc-option,-mabi=ms) || X86_32
1966	select RELOCATABLE
1967	help
1968	  This kernel feature allows a bzImage to be loaded directly
1969	  by EFI firmware without the use of a bootloader.
1970
1971	  See Documentation/admin-guide/efi-stub.rst for more information.
1972
1973config EFI_MIXED
1974	bool "EFI mixed-mode support"
1975	depends on EFI_STUB && X86_64
1976	help
1977	   Enabling this feature allows a 64-bit kernel to be booted
1978	   on a 32-bit firmware, provided that your CPU supports 64-bit
1979	   mode.
1980
1981	   Note that it is not possible to boot a mixed-mode enabled
1982	   kernel via the EFI boot stub - a bootloader that supports
1983	   the EFI handover protocol must be used.
1984
1985	   If unsure, say N.
1986
1987source "kernel/Kconfig.hz"
1988
1989config KEXEC
1990	bool "kexec system call"
1991	select KEXEC_CORE
1992	help
1993	  kexec is a system call that implements the ability to shutdown your
1994	  current kernel, and to start another kernel.  It is like a reboot
1995	  but it is independent of the system firmware.   And like a reboot
1996	  you can start any kernel with it, not just Linux.
1997
1998	  The name comes from the similarity to the exec system call.
1999
2000	  It is an ongoing process to be certain the hardware in a machine
2001	  is properly shutdown, so do not be surprised if this code does not
2002	  initially work for you.  As of this writing the exact hardware
2003	  interface is strongly in flux, so no good recommendation can be
2004	  made.
2005
2006config KEXEC_FILE
2007	bool "kexec file based system call"
2008	select KEXEC_CORE
2009	select BUILD_BIN2C
2010	depends on X86_64
2011	depends on CRYPTO=y
2012	depends on CRYPTO_SHA256=y
2013	help
2014	  This is new version of kexec system call. This system call is
2015	  file based and takes file descriptors as system call argument
2016	  for kernel and initramfs as opposed to list of segments as
2017	  accepted by previous system call.
2018
2019config ARCH_HAS_KEXEC_PURGATORY
2020	def_bool KEXEC_FILE
2021
2022config KEXEC_SIG
2023	bool "Verify kernel signature during kexec_file_load() syscall"
2024	depends on KEXEC_FILE
2025	help
2026
2027	  This option makes the kexec_file_load() syscall check for a valid
2028	  signature of the kernel image.  The image can still be loaded without
2029	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2030	  there's a signature that we can check, then it must be valid.
2031
2032	  In addition to this option, you need to enable signature
2033	  verification for the corresponding kernel image type being
2034	  loaded in order for this to work.
2035
2036config KEXEC_SIG_FORCE
2037	bool "Require a valid signature in kexec_file_load() syscall"
2038	depends on KEXEC_SIG
2039	help
2040	  This option makes kernel signature verification mandatory for
2041	  the kexec_file_load() syscall.
2042
2043config KEXEC_BZIMAGE_VERIFY_SIG
2044	bool "Enable bzImage signature verification support"
2045	depends on KEXEC_SIG
2046	depends on SIGNED_PE_FILE_VERIFICATION
2047	select SYSTEM_TRUSTED_KEYRING
2048	help
2049	  Enable bzImage signature verification support.
2050
2051config CRASH_DUMP
2052	bool "kernel crash dumps"
2053	depends on X86_64 || (X86_32 && HIGHMEM)
2054	help
2055	  Generate crash dump after being started by kexec.
2056	  This should be normally only set in special crash dump kernels
2057	  which are loaded in the main kernel with kexec-tools into
2058	  a specially reserved region and then later executed after
2059	  a crash by kdump/kexec. The crash dump kernel must be compiled
2060	  to a memory address not used by the main kernel or BIOS using
2061	  PHYSICAL_START, or it must be built as a relocatable image
2062	  (CONFIG_RELOCATABLE=y).
2063	  For more details see Documentation/admin-guide/kdump/kdump.rst
2064
2065config KEXEC_JUMP
2066	bool "kexec jump"
2067	depends on KEXEC && HIBERNATION
2068	help
2069	  Jump between original kernel and kexeced kernel and invoke
2070	  code in physical address mode via KEXEC
2071
2072config PHYSICAL_START
2073	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2074	default "0x1000000"
2075	help
2076	  This gives the physical address where the kernel is loaded.
2077
2078	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2079	  bzImage will decompress itself to above physical address and
2080	  run from there. Otherwise, bzImage will run from the address where
2081	  it has been loaded by the boot loader and will ignore above physical
2082	  address.
2083
2084	  In normal kdump cases one does not have to set/change this option
2085	  as now bzImage can be compiled as a completely relocatable image
2086	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2087	  address. This option is mainly useful for the folks who don't want
2088	  to use a bzImage for capturing the crash dump and want to use a
2089	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2090	  to be specifically compiled to run from a specific memory area
2091	  (normally a reserved region) and this option comes handy.
2092
2093	  So if you are using bzImage for capturing the crash dump,
2094	  leave the value here unchanged to 0x1000000 and set
2095	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2096	  for capturing the crash dump change this value to start of
2097	  the reserved region.  In other words, it can be set based on
2098	  the "X" value as specified in the "crashkernel=YM@XM"
2099	  command line boot parameter passed to the panic-ed
2100	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2101	  for more details about crash dumps.
2102
2103	  Usage of bzImage for capturing the crash dump is recommended as
2104	  one does not have to build two kernels. Same kernel can be used
2105	  as production kernel and capture kernel. Above option should have
2106	  gone away after relocatable bzImage support is introduced. But it
2107	  is present because there are users out there who continue to use
2108	  vmlinux for dump capture. This option should go away down the
2109	  line.
2110
2111	  Don't change this unless you know what you are doing.
2112
2113config RELOCATABLE
2114	bool "Build a relocatable kernel"
2115	default y
2116	help
2117	  This builds a kernel image that retains relocation information
2118	  so it can be loaded someplace besides the default 1MB.
2119	  The relocations tend to make the kernel binary about 10% larger,
2120	  but are discarded at runtime.
2121
2122	  One use is for the kexec on panic case where the recovery kernel
2123	  must live at a different physical address than the primary
2124	  kernel.
2125
2126	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2127	  it has been loaded at and the compile time physical address
2128	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2129
2130config RANDOMIZE_BASE
2131	bool "Randomize the address of the kernel image (KASLR)"
2132	depends on RELOCATABLE
2133	default y
2134	help
2135	  In support of Kernel Address Space Layout Randomization (KASLR),
2136	  this randomizes the physical address at which the kernel image
2137	  is decompressed and the virtual address where the kernel
2138	  image is mapped, as a security feature that deters exploit
2139	  attempts relying on knowledge of the location of kernel
2140	  code internals.
2141
2142	  On 64-bit, the kernel physical and virtual addresses are
2143	  randomized separately. The physical address will be anywhere
2144	  between 16MB and the top of physical memory (up to 64TB). The
2145	  virtual address will be randomized from 16MB up to 1GB (9 bits
2146	  of entropy). Note that this also reduces the memory space
2147	  available to kernel modules from 1.5GB to 1GB.
2148
2149	  On 32-bit, the kernel physical and virtual addresses are
2150	  randomized together. They will be randomized from 16MB up to
2151	  512MB (8 bits of entropy).
2152
2153	  Entropy is generated using the RDRAND instruction if it is
2154	  supported. If RDTSC is supported, its value is mixed into
2155	  the entropy pool as well. If neither RDRAND nor RDTSC are
2156	  supported, then entropy is read from the i8254 timer. The
2157	  usable entropy is limited by the kernel being built using
2158	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2159	  minimum of 2MB. As a result, only 10 bits of entropy are
2160	  theoretically possible, but the implementations are further
2161	  limited due to memory layouts.
2162
2163	  If unsure, say Y.
2164
2165# Relocation on x86 needs some additional build support
2166config X86_NEED_RELOCS
2167	def_bool y
2168	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2169
2170config PHYSICAL_ALIGN
2171	hex "Alignment value to which kernel should be aligned"
2172	default "0x200000"
2173	range 0x2000 0x1000000 if X86_32
2174	range 0x200000 0x1000000 if X86_64
2175	help
2176	  This value puts the alignment restrictions on physical address
2177	  where kernel is loaded and run from. Kernel is compiled for an
2178	  address which meets above alignment restriction.
2179
2180	  If bootloader loads the kernel at a non-aligned address and
2181	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2182	  address aligned to above value and run from there.
2183
2184	  If bootloader loads the kernel at a non-aligned address and
2185	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2186	  load address and decompress itself to the address it has been
2187	  compiled for and run from there. The address for which kernel is
2188	  compiled already meets above alignment restrictions. Hence the
2189	  end result is that kernel runs from a physical address meeting
2190	  above alignment restrictions.
2191
2192	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2193	  this value must be a multiple of 0x200000.
2194
2195	  Don't change this unless you know what you are doing.
2196
2197config DYNAMIC_MEMORY_LAYOUT
2198	bool
2199	help
2200	  This option makes base addresses of vmalloc and vmemmap as well as
2201	  __PAGE_OFFSET movable during boot.
2202
2203config RANDOMIZE_MEMORY
2204	bool "Randomize the kernel memory sections"
2205	depends on X86_64
2206	depends on RANDOMIZE_BASE
2207	select DYNAMIC_MEMORY_LAYOUT
2208	default RANDOMIZE_BASE
2209	help
2210	   Randomizes the base virtual address of kernel memory sections
2211	   (physical memory mapping, vmalloc & vmemmap). This security feature
2212	   makes exploits relying on predictable memory locations less reliable.
2213
2214	   The order of allocations remains unchanged. Entropy is generated in
2215	   the same way as RANDOMIZE_BASE. Current implementation in the optimal
2216	   configuration have in average 30,000 different possible virtual
2217	   addresses for each memory section.
2218
2219	   If unsure, say Y.
2220
2221config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2222	hex "Physical memory mapping padding" if EXPERT
2223	depends on RANDOMIZE_MEMORY
2224	default "0xa" if MEMORY_HOTPLUG
2225	default "0x0"
2226	range 0x1 0x40 if MEMORY_HOTPLUG
2227	range 0x0 0x40
2228	help
2229	   Define the padding in terabytes added to the existing physical
2230	   memory size during kernel memory randomization. It is useful
2231	   for memory hotplug support but reduces the entropy available for
2232	   address randomization.
2233
2234	   If unsure, leave at the default value.
2235
2236config HOTPLUG_CPU
2237	def_bool y
2238	depends on SMP
2239
2240config BOOTPARAM_HOTPLUG_CPU0
2241	bool "Set default setting of cpu0_hotpluggable"
2242	depends on HOTPLUG_CPU
2243	help
2244	  Set whether default state of cpu0_hotpluggable is on or off.
2245
2246	  Say Y here to enable CPU0 hotplug by default. If this switch
2247	  is turned on, there is no need to give cpu0_hotplug kernel
2248	  parameter and the CPU0 hotplug feature is enabled by default.
2249
2250	  Please note: there are two known CPU0 dependencies if you want
2251	  to enable the CPU0 hotplug feature either by this switch or by
2252	  cpu0_hotplug kernel parameter.
2253
2254	  First, resume from hibernate or suspend always starts from CPU0.
2255	  So hibernate and suspend are prevented if CPU0 is offline.
2256
2257	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2258	  offline if any interrupt can not migrate out of CPU0. There may
2259	  be other CPU0 dependencies.
2260
2261	  Please make sure the dependencies are under your control before
2262	  you enable this feature.
2263
2264	  Say N if you don't want to enable CPU0 hotplug feature by default.
2265	  You still can enable the CPU0 hotplug feature at boot by kernel
2266	  parameter cpu0_hotplug.
2267
2268config DEBUG_HOTPLUG_CPU0
2269	def_bool n
2270	prompt "Debug CPU0 hotplug"
2271	depends on HOTPLUG_CPU
2272	help
2273	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2274	  soon as possible and boots up userspace with CPU0 offlined. User
2275	  can online CPU0 back after boot time.
2276
2277	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2278	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2279	  compilation or giving cpu0_hotplug kernel parameter at boot.
2280
2281	  If unsure, say N.
2282
2283config COMPAT_VDSO
2284	def_bool n
2285	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2286	depends on COMPAT_32
2287	help
2288	  Certain buggy versions of glibc will crash if they are
2289	  presented with a 32-bit vDSO that is not mapped at the address
2290	  indicated in its segment table.
2291
2292	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2293	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2294	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2295	  the only released version with the bug, but OpenSUSE 9
2296	  contains a buggy "glibc 2.3.2".
2297
2298	  The symptom of the bug is that everything crashes on startup, saying:
2299	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2300
2301	  Saying Y here changes the default value of the vdso32 boot
2302	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2303	  This works around the glibc bug but hurts performance.
2304
2305	  If unsure, say N: if you are compiling your own kernel, you
2306	  are unlikely to be using a buggy version of glibc.
2307
2308choice
2309	prompt "vsyscall table for legacy applications"
2310	depends on X86_64
2311	default LEGACY_VSYSCALL_XONLY
2312	help
2313	  Legacy user code that does not know how to find the vDSO expects
2314	  to be able to issue three syscalls by calling fixed addresses in
2315	  kernel space. Since this location is not randomized with ASLR,
2316	  it can be used to assist security vulnerability exploitation.
2317
2318	  This setting can be changed at boot time via the kernel command
2319	  line parameter vsyscall=[emulate|xonly|none].
2320
2321	  On a system with recent enough glibc (2.14 or newer) and no
2322	  static binaries, you can say None without a performance penalty
2323	  to improve security.
2324
2325	  If unsure, select "Emulate execution only".
2326
2327	config LEGACY_VSYSCALL_EMULATE
2328		bool "Full emulation"
2329		help
2330		  The kernel traps and emulates calls into the fixed vsyscall
2331		  address mapping. This makes the mapping non-executable, but
2332		  it still contains readable known contents, which could be
2333		  used in certain rare security vulnerability exploits. This
2334		  configuration is recommended when using legacy userspace
2335		  that still uses vsyscalls along with legacy binary
2336		  instrumentation tools that require code to be readable.
2337
2338		  An example of this type of legacy userspace is running
2339		  Pin on an old binary that still uses vsyscalls.
2340
2341	config LEGACY_VSYSCALL_XONLY
2342		bool "Emulate execution only"
2343		help
2344		  The kernel traps and emulates calls into the fixed vsyscall
2345		  address mapping and does not allow reads.  This
2346		  configuration is recommended when userspace might use the
2347		  legacy vsyscall area but support for legacy binary
2348		  instrumentation of legacy code is not needed.  It mitigates
2349		  certain uses of the vsyscall area as an ASLR-bypassing
2350		  buffer.
2351
2352	config LEGACY_VSYSCALL_NONE
2353		bool "None"
2354		help
2355		  There will be no vsyscall mapping at all. This will
2356		  eliminate any risk of ASLR bypass due to the vsyscall
2357		  fixed address mapping. Attempts to use the vsyscalls
2358		  will be reported to dmesg, so that either old or
2359		  malicious userspace programs can be identified.
2360
2361endchoice
2362
2363config CMDLINE_BOOL
2364	bool "Built-in kernel command line"
2365	help
2366	  Allow for specifying boot arguments to the kernel at
2367	  build time.  On some systems (e.g. embedded ones), it is
2368	  necessary or convenient to provide some or all of the
2369	  kernel boot arguments with the kernel itself (that is,
2370	  to not rely on the boot loader to provide them.)
2371
2372	  To compile command line arguments into the kernel,
2373	  set this option to 'Y', then fill in the
2374	  boot arguments in CONFIG_CMDLINE.
2375
2376	  Systems with fully functional boot loaders (i.e. non-embedded)
2377	  should leave this option set to 'N'.
2378
2379config CMDLINE
2380	string "Built-in kernel command string"
2381	depends on CMDLINE_BOOL
2382	default ""
2383	help
2384	  Enter arguments here that should be compiled into the kernel
2385	  image and used at boot time.  If the boot loader provides a
2386	  command line at boot time, it is appended to this string to
2387	  form the full kernel command line, when the system boots.
2388
2389	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2390	  change this behavior.
2391
2392	  In most cases, the command line (whether built-in or provided
2393	  by the boot loader) should specify the device for the root
2394	  file system.
2395
2396config CMDLINE_OVERRIDE
2397	bool "Built-in command line overrides boot loader arguments"
2398	depends on CMDLINE_BOOL && CMDLINE != ""
2399	help
2400	  Set this option to 'Y' to have the kernel ignore the boot loader
2401	  command line, and use ONLY the built-in command line.
2402
2403	  This is used to work around broken boot loaders.  This should
2404	  be set to 'N' under normal conditions.
2405
2406config MODIFY_LDT_SYSCALL
2407	bool "Enable the LDT (local descriptor table)" if EXPERT
2408	default y
2409	help
2410	  Linux can allow user programs to install a per-process x86
2411	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2412	  call.  This is required to run 16-bit or segmented code such as
2413	  DOSEMU or some Wine programs.  It is also used by some very old
2414	  threading libraries.
2415
2416	  Enabling this feature adds a small amount of overhead to
2417	  context switches and increases the low-level kernel attack
2418	  surface.  Disabling it removes the modify_ldt(2) system call.
2419
2420	  Saying 'N' here may make sense for embedded or server kernels.
2421
2422source "kernel/livepatch/Kconfig"
2423
2424endmenu
2425
2426config ARCH_HAS_ADD_PAGES
2427	def_bool y
2428	depends on X86_64 && ARCH_ENABLE_MEMORY_HOTPLUG
2429
2430config ARCH_ENABLE_MEMORY_HOTPLUG
2431	def_bool y
2432	depends on X86_64 || (X86_32 && HIGHMEM)
2433
2434config ARCH_ENABLE_MEMORY_HOTREMOVE
2435	def_bool y
2436	depends on MEMORY_HOTPLUG
2437
2438config USE_PERCPU_NUMA_NODE_ID
2439	def_bool y
2440	depends on NUMA
2441
2442config ARCH_ENABLE_SPLIT_PMD_PTLOCK
2443	def_bool y
2444	depends on X86_64 || X86_PAE
2445
2446config ARCH_ENABLE_HUGEPAGE_MIGRATION
2447	def_bool y
2448	depends on X86_64 && HUGETLB_PAGE && MIGRATION
2449
2450config ARCH_ENABLE_THP_MIGRATION
2451	def_bool y
2452	depends on X86_64 && TRANSPARENT_HUGEPAGE
2453
2454menu "Power management and ACPI options"
2455
2456config ARCH_HIBERNATION_HEADER
2457	def_bool y
2458	depends on HIBERNATION
2459
2460source "kernel/power/Kconfig"
2461
2462source "drivers/acpi/Kconfig"
2463
2464config X86_APM_BOOT
2465	def_bool y
2466	depends on APM
2467
2468menuconfig APM
2469	tristate "APM (Advanced Power Management) BIOS support"
2470	depends on X86_32 && PM_SLEEP
2471	help
2472	  APM is a BIOS specification for saving power using several different
2473	  techniques. This is mostly useful for battery powered laptops with
2474	  APM compliant BIOSes. If you say Y here, the system time will be
2475	  reset after a RESUME operation, the /proc/apm device will provide
2476	  battery status information, and user-space programs will receive
2477	  notification of APM "events" (e.g. battery status change).
2478
2479	  If you select "Y" here, you can disable actual use of the APM
2480	  BIOS by passing the "apm=off" option to the kernel at boot time.
2481
2482	  Note that the APM support is almost completely disabled for
2483	  machines with more than one CPU.
2484
2485	  In order to use APM, you will need supporting software. For location
2486	  and more information, read <file:Documentation/power/apm-acpi.rst>
2487	  and the Battery Powered Linux mini-HOWTO, available from
2488	  <http://www.tldp.org/docs.html#howto>.
2489
2490	  This driver does not spin down disk drives (see the hdparm(8)
2491	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2492	  VESA-compliant "green" monitors.
2493
2494	  This driver does not support the TI 4000M TravelMate and the ACER
2495	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2496	  desktop machines also don't have compliant BIOSes, and this driver
2497	  may cause those machines to panic during the boot phase.
2498
2499	  Generally, if you don't have a battery in your machine, there isn't
2500	  much point in using this driver and you should say N. If you get
2501	  random kernel OOPSes or reboots that don't seem to be related to
2502	  anything, try disabling/enabling this option (or disabling/enabling
2503	  APM in your BIOS).
2504
2505	  Some other things you should try when experiencing seemingly random,
2506	  "weird" problems:
2507
2508	  1) make sure that you have enough swap space and that it is
2509	  enabled.
2510	  2) pass the "no-hlt" option to the kernel
2511	  3) switch on floating point emulation in the kernel and pass
2512	  the "no387" option to the kernel
2513	  4) pass the "floppy=nodma" option to the kernel
2514	  5) pass the "mem=4M" option to the kernel (thereby disabling
2515	  all but the first 4 MB of RAM)
2516	  6) make sure that the CPU is not over clocked.
2517	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2518	  8) disable the cache from your BIOS settings
2519	  9) install a fan for the video card or exchange video RAM
2520	  10) install a better fan for the CPU
2521	  11) exchange RAM chips
2522	  12) exchange the motherboard.
2523
2524	  To compile this driver as a module, choose M here: the
2525	  module will be called apm.
2526
2527if APM
2528
2529config APM_IGNORE_USER_SUSPEND
2530	bool "Ignore USER SUSPEND"
2531	help
2532	  This option will ignore USER SUSPEND requests. On machines with a
2533	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2534	  series notebooks, it is necessary to say Y because of a BIOS bug.
2535
2536config APM_DO_ENABLE
2537	bool "Enable PM at boot time"
2538	help
2539	  Enable APM features at boot time. From page 36 of the APM BIOS
2540	  specification: "When disabled, the APM BIOS does not automatically
2541	  power manage devices, enter the Standby State, enter the Suspend
2542	  State, or take power saving steps in response to CPU Idle calls."
2543	  This driver will make CPU Idle calls when Linux is idle (unless this
2544	  feature is turned off -- see "Do CPU IDLE calls", below). This
2545	  should always save battery power, but more complicated APM features
2546	  will be dependent on your BIOS implementation. You may need to turn
2547	  this option off if your computer hangs at boot time when using APM
2548	  support, or if it beeps continuously instead of suspending. Turn
2549	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2550	  T400CDT. This is off by default since most machines do fine without
2551	  this feature.
2552
2553config APM_CPU_IDLE
2554	depends on CPU_IDLE
2555	bool "Make CPU Idle calls when idle"
2556	help
2557	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2558	  On some machines, this can activate improved power savings, such as
2559	  a slowed CPU clock rate, when the machine is idle. These idle calls
2560	  are made after the idle loop has run for some length of time (e.g.,
2561	  333 mS). On some machines, this will cause a hang at boot time or
2562	  whenever the CPU becomes idle. (On machines with more than one CPU,
2563	  this option does nothing.)
2564
2565config APM_DISPLAY_BLANK
2566	bool "Enable console blanking using APM"
2567	help
2568	  Enable console blanking using the APM. Some laptops can use this to
2569	  turn off the LCD backlight when the screen blanker of the Linux
2570	  virtual console blanks the screen. Note that this is only used by
2571	  the virtual console screen blanker, and won't turn off the backlight
2572	  when using the X Window system. This also doesn't have anything to
2573	  do with your VESA-compliant power-saving monitor. Further, this
2574	  option doesn't work for all laptops -- it might not turn off your
2575	  backlight at all, or it might print a lot of errors to the console,
2576	  especially if you are using gpm.
2577
2578config APM_ALLOW_INTS
2579	bool "Allow interrupts during APM BIOS calls"
2580	help
2581	  Normally we disable external interrupts while we are making calls to
2582	  the APM BIOS as a measure to lessen the effects of a badly behaving
2583	  BIOS implementation.  The BIOS should reenable interrupts if it
2584	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2585	  many of the newer IBM Thinkpads.  If you experience hangs when you
2586	  suspend, try setting this to Y.  Otherwise, say N.
2587
2588endif # APM
2589
2590source "drivers/cpufreq/Kconfig"
2591
2592source "drivers/cpuidle/Kconfig"
2593
2594source "drivers/idle/Kconfig"
2595
2596endmenu
2597
2598
2599menu "Bus options (PCI etc.)"
2600
2601choice
2602	prompt "PCI access mode"
2603	depends on X86_32 && PCI
2604	default PCI_GOANY
2605	help
2606	  On PCI systems, the BIOS can be used to detect the PCI devices and
2607	  determine their configuration. However, some old PCI motherboards
2608	  have BIOS bugs and may crash if this is done. Also, some embedded
2609	  PCI-based systems don't have any BIOS at all. Linux can also try to
2610	  detect the PCI hardware directly without using the BIOS.
2611
2612	  With this option, you can specify how Linux should detect the
2613	  PCI devices. If you choose "BIOS", the BIOS will be used,
2614	  if you choose "Direct", the BIOS won't be used, and if you
2615	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2616	  If you choose "Any", the kernel will try MMCONFIG, then the
2617	  direct access method and falls back to the BIOS if that doesn't
2618	  work. If unsure, go with the default, which is "Any".
2619
2620config PCI_GOBIOS
2621	bool "BIOS"
2622
2623config PCI_GOMMCONFIG
2624	bool "MMConfig"
2625
2626config PCI_GODIRECT
2627	bool "Direct"
2628
2629config PCI_GOOLPC
2630	bool "OLPC XO-1"
2631	depends on OLPC
2632
2633config PCI_GOANY
2634	bool "Any"
2635
2636endchoice
2637
2638config PCI_BIOS
2639	def_bool y
2640	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2641
2642# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2643config PCI_DIRECT
2644	def_bool y
2645	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2646
2647config PCI_MMCONFIG
2648	bool "Support mmconfig PCI config space access" if X86_64
2649	default y
2650	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2651	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2652
2653config PCI_OLPC
2654	def_bool y
2655	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2656
2657config PCI_XEN
2658	def_bool y
2659	depends on PCI && XEN
2660	select SWIOTLB_XEN
2661
2662config MMCONF_FAM10H
2663	def_bool y
2664	depends on X86_64 && PCI_MMCONFIG && ACPI
2665
2666config PCI_CNB20LE_QUIRK
2667	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2668	depends on PCI
2669	help
2670	  Read the PCI windows out of the CNB20LE host bridge. This allows
2671	  PCI hotplug to work on systems with the CNB20LE chipset which do
2672	  not have ACPI.
2673
2674	  There's no public spec for this chipset, and this functionality
2675	  is known to be incomplete.
2676
2677	  You should say N unless you know you need this.
2678
2679config ISA_BUS
2680	bool "ISA bus support on modern systems" if EXPERT
2681	help
2682	  Expose ISA bus device drivers and options available for selection and
2683	  configuration. Enable this option if your target machine has an ISA
2684	  bus. ISA is an older system, displaced by PCI and newer bus
2685	  architectures -- if your target machine is modern, it probably does
2686	  not have an ISA bus.
2687
2688	  If unsure, say N.
2689
2690# x86_64 have no ISA slots, but can have ISA-style DMA.
2691config ISA_DMA_API
2692	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2693	default y
2694	help
2695	  Enables ISA-style DMA support for devices requiring such controllers.
2696	  If unsure, say Y.
2697
2698if X86_32
2699
2700config ISA
2701	bool "ISA support"
2702	help
2703	  Find out whether you have ISA slots on your motherboard.  ISA is the
2704	  name of a bus system, i.e. the way the CPU talks to the other stuff
2705	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2706	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2707	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2708
2709config SCx200
2710	tristate "NatSemi SCx200 support"
2711	help
2712	  This provides basic support for National Semiconductor's
2713	  (now AMD's) Geode processors.  The driver probes for the
2714	  PCI-IDs of several on-chip devices, so its a good dependency
2715	  for other scx200_* drivers.
2716
2717	  If compiled as a module, the driver is named scx200.
2718
2719config SCx200HR_TIMER
2720	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2721	depends on SCx200
2722	default y
2723	help
2724	  This driver provides a clocksource built upon the on-chip
2725	  27MHz high-resolution timer.  Its also a workaround for
2726	  NSC Geode SC-1100's buggy TSC, which loses time when the
2727	  processor goes idle (as is done by the scheduler).  The
2728	  other workaround is idle=poll boot option.
2729
2730config OLPC
2731	bool "One Laptop Per Child support"
2732	depends on !X86_PAE
2733	select GPIOLIB
2734	select OF
2735	select OF_PROMTREE
2736	select IRQ_DOMAIN
2737	select OLPC_EC
2738	help
2739	  Add support for detecting the unique features of the OLPC
2740	  XO hardware.
2741
2742config OLPC_XO1_PM
2743	bool "OLPC XO-1 Power Management"
2744	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2745	help
2746	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2747
2748config OLPC_XO1_RTC
2749	bool "OLPC XO-1 Real Time Clock"
2750	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2751	help
2752	  Add support for the XO-1 real time clock, which can be used as a
2753	  programmable wakeup source.
2754
2755config OLPC_XO1_SCI
2756	bool "OLPC XO-1 SCI extras"
2757	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2758	depends on INPUT=y
2759	select POWER_SUPPLY
2760	help
2761	  Add support for SCI-based features of the OLPC XO-1 laptop:
2762	   - EC-driven system wakeups
2763	   - Power button
2764	   - Ebook switch
2765	   - Lid switch
2766	   - AC adapter status updates
2767	   - Battery status updates
2768
2769config OLPC_XO15_SCI
2770	bool "OLPC XO-1.5 SCI extras"
2771	depends on OLPC && ACPI
2772	select POWER_SUPPLY
2773	help
2774	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2775	   - EC-driven system wakeups
2776	   - AC adapter status updates
2777	   - Battery status updates
2778
2779config ALIX
2780	bool "PCEngines ALIX System Support (LED setup)"
2781	select GPIOLIB
2782	help
2783	  This option enables system support for the PCEngines ALIX.
2784	  At present this just sets up LEDs for GPIO control on
2785	  ALIX2/3/6 boards.  However, other system specific setup should
2786	  get added here.
2787
2788	  Note: You must still enable the drivers for GPIO and LED support
2789	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2790
2791	  Note: You have to set alix.force=1 for boards with Award BIOS.
2792
2793config NET5501
2794	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2795	select GPIOLIB
2796	help
2797	  This option enables system support for the Soekris Engineering net5501.
2798
2799config GEOS
2800	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2801	select GPIOLIB
2802	depends on DMI
2803	help
2804	  This option enables system support for the Traverse Technologies GEOS.
2805
2806config TS5500
2807	bool "Technologic Systems TS-5500 platform support"
2808	depends on MELAN
2809	select CHECK_SIGNATURE
2810	select NEW_LEDS
2811	select LEDS_CLASS
2812	help
2813	  This option enables system support for the Technologic Systems TS-5500.
2814
2815endif # X86_32
2816
2817config AMD_NB
2818	def_bool y
2819	depends on CPU_SUP_AMD && PCI
2820
2821config X86_SYSFB
2822	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
2823	help
2824	  Firmwares often provide initial graphics framebuffers so the BIOS,
2825	  bootloader or kernel can show basic video-output during boot for
2826	  user-guidance and debugging. Historically, x86 used the VESA BIOS
2827	  Extensions and EFI-framebuffers for this, which are mostly limited
2828	  to x86.
2829	  This option, if enabled, marks VGA/VBE/EFI framebuffers as generic
2830	  framebuffers so the new generic system-framebuffer drivers can be
2831	  used on x86. If the framebuffer is not compatible with the generic
2832	  modes, it is advertised as fallback platform framebuffer so legacy
2833	  drivers like efifb, vesafb and uvesafb can pick it up.
2834	  If this option is not selected, all system framebuffers are always
2835	  marked as fallback platform framebuffers as usual.
2836
2837	  Note: Legacy fbdev drivers, including vesafb, efifb, uvesafb, will
2838	  not be able to pick up generic system framebuffers if this option
2839	  is selected. You are highly encouraged to enable simplefb as
2840	  replacement if you select this option. simplefb can correctly deal
2841	  with generic system framebuffers. But you should still keep vesafb
2842	  and others enabled as fallback if a system framebuffer is
2843	  incompatible with simplefb.
2844
2845	  If unsure, say Y.
2846
2847endmenu
2848
2849
2850menu "Binary Emulations"
2851
2852config IA32_EMULATION
2853	bool "IA32 Emulation"
2854	depends on X86_64
2855	select ARCH_WANT_OLD_COMPAT_IPC
2856	select BINFMT_ELF
2857	select COMPAT_OLD_SIGACTION
2858	help
2859	  Include code to run legacy 32-bit programs under a
2860	  64-bit kernel. You should likely turn this on, unless you're
2861	  100% sure that you don't have any 32-bit programs left.
2862
2863config IA32_AOUT
2864	tristate "IA32 a.out support"
2865	depends on IA32_EMULATION
2866	depends on BROKEN
2867	help
2868	  Support old a.out binaries in the 32bit emulation.
2869
2870config X86_X32
2871	bool "x32 ABI for 64-bit mode"
2872	depends on X86_64
2873	help
2874	  Include code to run binaries for the x32 native 32-bit ABI
2875	  for 64-bit processors.  An x32 process gets access to the
2876	  full 64-bit register file and wide data path while leaving
2877	  pointers at 32 bits for smaller memory footprint.
2878
2879	  You will need a recent binutils (2.22 or later) with
2880	  elf32_x86_64 support enabled to compile a kernel with this
2881	  option set.
2882
2883config COMPAT_32
2884	def_bool y
2885	depends on IA32_EMULATION || X86_32
2886	select HAVE_UID16
2887	select OLD_SIGSUSPEND3
2888
2889config COMPAT
2890	def_bool y
2891	depends on IA32_EMULATION || X86_X32
2892
2893if COMPAT
2894config COMPAT_FOR_U64_ALIGNMENT
2895	def_bool y
2896
2897config SYSVIPC_COMPAT
2898	def_bool y
2899	depends on SYSVIPC
2900endif
2901
2902endmenu
2903
2904
2905config HAVE_ATOMIC_IOMAP
2906	def_bool y
2907	depends on X86_32
2908
2909source "drivers/firmware/Kconfig"
2910
2911source "arch/x86/kvm/Kconfig"
2912
2913source "arch/x86/Kconfig.assembler"
2914