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_SUPPORTS_PER_VMA_LOCK
31	select ARCH_USE_CMPXCHG_LOCKREF
32	select HAVE_ARCH_SOFT_DIRTY
33	select MODULES_USE_ELF_RELA
34	select NEED_DMA_MAP_STATE
35	select SWIOTLB
36	select ARCH_HAS_ELFCORE_COMPAT
37	select ZONE_DMA32
38
39config FORCE_DYNAMIC_FTRACE
40	def_bool y
41	depends on X86_32
42	depends on FUNCTION_TRACER
43	select DYNAMIC_FTRACE
44	help
45	  We keep the static function tracing (!DYNAMIC_FTRACE) around
46	  in order to test the non static function tracing in the
47	  generic code, as other architectures still use it. But we
48	  only need to keep it around for x86_64. No need to keep it
49	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
50#
51# Arch settings
52#
53# ( Note that options that are marked 'if X86_64' could in principle be
54#   ported to 32-bit as well. )
55#
56config X86
57	def_bool y
58	#
59	# Note: keep this list sorted alphabetically
60	#
61	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
62	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
63	select ARCH_32BIT_OFF_T			if X86_32
64	select ARCH_CLOCKSOURCE_INIT
65	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
66	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
67	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
68	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
69	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
70	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
71	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
72	select ARCH_HAS_CACHE_LINE_SIZE
73	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
74	select ARCH_HAS_CPU_FINALIZE_INIT
75	select ARCH_HAS_CURRENT_STACK_POINTER
76	select ARCH_HAS_DEBUG_VIRTUAL
77	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
78	select ARCH_HAS_DEVMEM_IS_ALLOWED
79	select ARCH_HAS_EARLY_DEBUG		if KGDB
80	select ARCH_HAS_ELF_RANDOMIZE
81	select ARCH_HAS_FAST_MULTIPLIER
82	select ARCH_HAS_FORTIFY_SOURCE
83	select ARCH_HAS_GCOV_PROFILE_ALL
84	select ARCH_HAS_KCOV			if X86_64
85	select ARCH_HAS_MEM_ENCRYPT
86	select ARCH_HAS_MEMBARRIER_SYNC_CORE
87	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
88	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
89	select ARCH_HAS_PMEM_API		if X86_64
90	select ARCH_HAS_PTE_DEVMAP		if X86_64
91	select ARCH_HAS_PTE_SPECIAL
92	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
93	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
94	select ARCH_HAS_COPY_MC			if X86_64
95	select ARCH_HAS_SET_MEMORY
96	select ARCH_HAS_SET_DIRECT_MAP
97	select ARCH_HAS_STRICT_KERNEL_RWX
98	select ARCH_HAS_STRICT_MODULE_RWX
99	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
100	select ARCH_HAS_SYSCALL_WRAPPER
101	select ARCH_HAS_UBSAN_SANITIZE_ALL
102	select ARCH_HAS_DEBUG_WX
103	select ARCH_HAS_ZONE_DMA_SET if EXPERT
104	select ARCH_HAVE_NMI_SAFE_CMPXCHG
105	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
106	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
107	select ARCH_MIGHT_HAVE_PC_PARPORT
108	select ARCH_MIGHT_HAVE_PC_SERIO
109	select ARCH_STACKWALK
110	select ARCH_SUPPORTS_ACPI
111	select ARCH_SUPPORTS_ATOMIC_RMW
112	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
113	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
114	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
115	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
116	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
117	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
118	select ARCH_SUPPORTS_LTO_CLANG
119	select ARCH_SUPPORTS_LTO_CLANG_THIN
120	select ARCH_USE_BUILTIN_BSWAP
121	select ARCH_USE_MEMTEST
122	select ARCH_USE_QUEUED_RWLOCKS
123	select ARCH_USE_QUEUED_SPINLOCKS
124	select ARCH_USE_SYM_ANNOTATIONS
125	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
126	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
127	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
128	select ARCH_WANTS_NO_INSTR
129	select ARCH_WANT_GENERAL_HUGETLB
130	select ARCH_WANT_HUGE_PMD_SHARE
131	select ARCH_WANT_LD_ORPHAN_WARN
132	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
133	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
134	select ARCH_WANTS_THP_SWAP		if X86_64
135	select ARCH_HAS_PARANOID_L1D_FLUSH
136	select BUILDTIME_TABLE_SORT
137	select CLKEVT_I8253
138	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
139	select CLOCKSOURCE_WATCHDOG
140	# Word-size accesses may read uninitialized data past the trailing \0
141	# in strings and cause false KMSAN reports.
142	select DCACHE_WORD_ACCESS		if !KMSAN
143	select DYNAMIC_SIGFRAME
144	select EDAC_ATOMIC_SCRUB
145	select EDAC_SUPPORT
146	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
147	select GENERIC_CLOCKEVENTS_MIN_ADJUST
148	select GENERIC_CMOS_UPDATE
149	select GENERIC_CPU_AUTOPROBE
150	select GENERIC_CPU_VULNERABILITIES
151	select GENERIC_EARLY_IOREMAP
152	select GENERIC_ENTRY
153	select GENERIC_IOMAP
154	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
155	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
156	select GENERIC_IRQ_MIGRATION		if SMP
157	select GENERIC_IRQ_PROBE
158	select GENERIC_IRQ_RESERVATION_MODE
159	select GENERIC_IRQ_SHOW
160	select GENERIC_PENDING_IRQ		if SMP
161	select GENERIC_PTDUMP
162	select GENERIC_SMP_IDLE_THREAD
163	select GENERIC_TIME_VSYSCALL
164	select GENERIC_GETTIMEOFDAY
165	select GENERIC_VDSO_TIME_NS
166	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
167	select HARDIRQS_SW_RESEND
168	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
169	select HAS_IOPORT
170	select HAVE_ACPI_APEI			if ACPI
171	select HAVE_ACPI_APEI_NMI		if ACPI
172	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
173	select HAVE_ARCH_AUDITSYSCALL
174	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
175	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
176	select HAVE_ARCH_JUMP_LABEL
177	select HAVE_ARCH_JUMP_LABEL_RELATIVE
178	select HAVE_ARCH_KASAN			if X86_64
179	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
180	select HAVE_ARCH_KFENCE
181	select HAVE_ARCH_KMSAN			if X86_64
182	select HAVE_ARCH_KGDB
183	select HAVE_ARCH_MMAP_RND_BITS		if MMU
184	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
185	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
186	select HAVE_ARCH_PREL32_RELOCATIONS
187	select HAVE_ARCH_SECCOMP_FILTER
188	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
189	select HAVE_ARCH_STACKLEAK
190	select HAVE_ARCH_TRACEHOOK
191	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
192	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
193	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
194	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
195	select HAVE_ARCH_VMAP_STACK		if X86_64
196	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
197	select HAVE_ARCH_WITHIN_STACK_FRAMES
198	select HAVE_ASM_MODVERSIONS
199	select HAVE_CMPXCHG_DOUBLE
200	select HAVE_CMPXCHG_LOCAL
201	select HAVE_CONTEXT_TRACKING_USER		if X86_64
202	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
203	select HAVE_C_RECORDMCOUNT
204	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
205	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
206	select HAVE_BUILDTIME_MCOUNT_SORT
207	select HAVE_DEBUG_KMEMLEAK
208	select HAVE_DMA_CONTIGUOUS
209	select HAVE_DYNAMIC_FTRACE
210	select HAVE_DYNAMIC_FTRACE_WITH_REGS
211	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
212	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
213	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
214	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
215	select HAVE_EBPF_JIT
216	select HAVE_EFFICIENT_UNALIGNED_ACCESS
217	select HAVE_EISA
218	select HAVE_EXIT_THREAD
219	select HAVE_FAST_GUP
220	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
221	select HAVE_FTRACE_MCOUNT_RECORD
222	select HAVE_FUNCTION_GRAPH_RETVAL	if HAVE_FUNCTION_GRAPH_TRACER
223	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
224	select HAVE_FUNCTION_TRACER
225	select HAVE_GCC_PLUGINS
226	select HAVE_HW_BREAKPOINT
227	select HAVE_IOREMAP_PROT
228	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
229	select HAVE_IRQ_TIME_ACCOUNTING
230	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
231	select HAVE_KERNEL_BZIP2
232	select HAVE_KERNEL_GZIP
233	select HAVE_KERNEL_LZ4
234	select HAVE_KERNEL_LZMA
235	select HAVE_KERNEL_LZO
236	select HAVE_KERNEL_XZ
237	select HAVE_KERNEL_ZSTD
238	select HAVE_KPROBES
239	select HAVE_KPROBES_ON_FTRACE
240	select HAVE_FUNCTION_ERROR_INJECTION
241	select HAVE_KRETPROBES
242	select HAVE_RETHOOK
243	select HAVE_KVM
244	select HAVE_LIVEPATCH			if X86_64
245	select HAVE_MIXED_BREAKPOINTS_REGS
246	select HAVE_MOD_ARCH_SPECIFIC
247	select HAVE_MOVE_PMD
248	select HAVE_MOVE_PUD
249	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
250	select HAVE_NMI
251	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
252	select HAVE_OBJTOOL			if X86_64
253	select HAVE_OPTPROBES
254	select HAVE_PCSPKR_PLATFORM
255	select HAVE_PERF_EVENTS
256	select HAVE_PERF_EVENTS_NMI
257	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
258	select HAVE_PCI
259	select HAVE_PERF_REGS
260	select HAVE_PERF_USER_STACK_DUMP
261	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
262	select MMU_GATHER_MERGE_VMAS
263	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
264	select HAVE_REGS_AND_STACK_ACCESS_API
265	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
266	select HAVE_FUNCTION_ARG_ACCESS_API
267	select HAVE_SETUP_PER_CPU_AREA
268	select HAVE_SOFTIRQ_ON_OWN_STACK
269	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
270	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
271	select HAVE_STATIC_CALL
272	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
273	select HAVE_PREEMPT_DYNAMIC_CALL
274	select HAVE_RSEQ
275	select HAVE_RUST			if X86_64
276	select HAVE_SYSCALL_TRACEPOINTS
277	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
278	select HAVE_UNSTABLE_SCHED_CLOCK
279	select HAVE_USER_RETURN_NOTIFIER
280	select HAVE_GENERIC_VDSO
281	select HOTPLUG_PARALLEL			if SMP && X86_64
282	select HOTPLUG_SMT			if SMP
283	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
284	select IRQ_FORCED_THREADING
285	select LOCK_MM_AND_FIND_VMA
286	select NEED_PER_CPU_EMBED_FIRST_CHUNK
287	select NEED_PER_CPU_PAGE_FIRST_CHUNK
288	select NEED_SG_DMA_LENGTH
289	select PCI_DOMAINS			if PCI
290	select PCI_LOCKLESS_CONFIG		if PCI
291	select PERF_EVENTS
292	select RTC_LIB
293	select RTC_MC146818_LIB
294	select SPARSE_IRQ
295	select SYSCTL_EXCEPTION_TRACE
296	select THREAD_INFO_IN_TASK
297	select TRACE_IRQFLAGS_SUPPORT
298	select TRACE_IRQFLAGS_NMI_SUPPORT
299	select USER_STACKTRACE_SUPPORT
300	select HAVE_ARCH_KCSAN			if X86_64
301	select PROC_PID_ARCH_STATUS		if PROC_FS
302	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
303	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
304	select FUNCTION_ALIGNMENT_4B
305	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
306	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
307
308config INSTRUCTION_DECODER
309	def_bool y
310	depends on KPROBES || PERF_EVENTS || UPROBES
311
312config OUTPUT_FORMAT
313	string
314	default "elf32-i386" if X86_32
315	default "elf64-x86-64" if X86_64
316
317config LOCKDEP_SUPPORT
318	def_bool y
319
320config STACKTRACE_SUPPORT
321	def_bool y
322
323config MMU
324	def_bool y
325
326config ARCH_MMAP_RND_BITS_MIN
327	default 28 if 64BIT
328	default 8
329
330config ARCH_MMAP_RND_BITS_MAX
331	default 32 if 64BIT
332	default 16
333
334config ARCH_MMAP_RND_COMPAT_BITS_MIN
335	default 8
336
337config ARCH_MMAP_RND_COMPAT_BITS_MAX
338	default 16
339
340config SBUS
341	bool
342
343config GENERIC_ISA_DMA
344	def_bool y
345	depends on ISA_DMA_API
346
347config GENERIC_CSUM
348	bool
349	default y if KMSAN || KASAN
350
351config GENERIC_BUG
352	def_bool y
353	depends on BUG
354	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
355
356config GENERIC_BUG_RELATIVE_POINTERS
357	bool
358
359config ARCH_MAY_HAVE_PC_FDC
360	def_bool y
361	depends on ISA_DMA_API
362
363config GENERIC_CALIBRATE_DELAY
364	def_bool y
365
366config ARCH_HAS_CPU_RELAX
367	def_bool y
368
369config ARCH_HIBERNATION_POSSIBLE
370	def_bool y
371
372config ARCH_SUSPEND_POSSIBLE
373	def_bool y
374
375config AUDIT_ARCH
376	def_bool y if X86_64
377
378config KASAN_SHADOW_OFFSET
379	hex
380	depends on KASAN
381	default 0xdffffc0000000000
382
383config HAVE_INTEL_TXT
384	def_bool y
385	depends on INTEL_IOMMU && ACPI
386
387config X86_32_SMP
388	def_bool y
389	depends on X86_32 && SMP
390
391config X86_64_SMP
392	def_bool y
393	depends on X86_64 && SMP
394
395config ARCH_SUPPORTS_UPROBES
396	def_bool y
397
398config FIX_EARLYCON_MEM
399	def_bool y
400
401config DYNAMIC_PHYSICAL_MASK
402	bool
403
404config PGTABLE_LEVELS
405	int
406	default 5 if X86_5LEVEL
407	default 4 if X86_64
408	default 3 if X86_PAE
409	default 2
410
411config CC_HAS_SANE_STACKPROTECTOR
412	bool
413	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
414	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
415	help
416	  We have to make sure stack protector is unconditionally disabled if
417	  the compiler produces broken code or if it does not let us control
418	  the segment on 32-bit kernels.
419
420menu "Processor type and features"
421
422config SMP
423	bool "Symmetric multi-processing support"
424	help
425	  This enables support for systems with more than one CPU. If you have
426	  a system with only one CPU, say N. If you have a system with more
427	  than one CPU, say Y.
428
429	  If you say N here, the kernel will run on uni- and multiprocessor
430	  machines, but will use only one CPU of a multiprocessor machine. If
431	  you say Y here, the kernel will run on many, but not all,
432	  uniprocessor machines. On a uniprocessor machine, the kernel
433	  will run faster if you say N here.
434
435	  Note that if you say Y here and choose architecture "586" or
436	  "Pentium" under "Processor family", the kernel will not work on 486
437	  architectures. Similarly, multiprocessor kernels for the "PPro"
438	  architecture may not work on all Pentium based boards.
439
440	  People using multiprocessor machines who say Y here should also say
441	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
442	  Management" code will be disabled if you say Y here.
443
444	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
445	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
446	  <http://www.tldp.org/docs.html#howto>.
447
448	  If you don't know what to do here, say N.
449
450config X86_X2APIC
451	bool "Support x2apic"
452	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
453	help
454	  This enables x2apic support on CPUs that have this feature.
455
456	  This allows 32-bit apic IDs (so it can support very large systems),
457	  and accesses the local apic via MSRs not via mmio.
458
459	  Some Intel systems circa 2022 and later are locked into x2APIC mode
460	  and can not fall back to the legacy APIC modes if SGX or TDX are
461	  enabled in the BIOS. They will boot with very reduced functionality
462	  without enabling this option.
463
464	  If you don't know what to do here, say N.
465
466config X86_MPPARSE
467	bool "Enable MPS table" if ACPI
468	default y
469	depends on X86_LOCAL_APIC
470	help
471	  For old smp systems that do not have proper acpi support. Newer systems
472	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
473
474config GOLDFISH
475	def_bool y
476	depends on X86_GOLDFISH
477
478config X86_CPU_RESCTRL
479	bool "x86 CPU resource control support"
480	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
481	select KERNFS
482	select PROC_CPU_RESCTRL		if PROC_FS
483	help
484	  Enable x86 CPU resource control support.
485
486	  Provide support for the allocation and monitoring of system resources
487	  usage by the CPU.
488
489	  Intel calls this Intel Resource Director Technology
490	  (Intel(R) RDT). More information about RDT can be found in the
491	  Intel x86 Architecture Software Developer Manual.
492
493	  AMD calls this AMD Platform Quality of Service (AMD QoS).
494	  More information about AMD QoS can be found in the AMD64 Technology
495	  Platform Quality of Service Extensions manual.
496
497	  Say N if unsure.
498
499if X86_32
500config X86_BIGSMP
501	bool "Support for big SMP systems with more than 8 CPUs"
502	depends on SMP
503	help
504	  This option is needed for the systems that have more than 8 CPUs.
505
506config X86_EXTENDED_PLATFORM
507	bool "Support for extended (non-PC) x86 platforms"
508	default y
509	help
510	  If you disable this option then the kernel will only support
511	  standard PC platforms. (which covers the vast majority of
512	  systems out there.)
513
514	  If you enable this option then you'll be able to select support
515	  for the following (non-PC) 32 bit x86 platforms:
516		Goldfish (Android emulator)
517		AMD Elan
518		RDC R-321x SoC
519		SGI 320/540 (Visual Workstation)
520		STA2X11-based (e.g. Northville)
521		Moorestown MID devices
522
523	  If you have one of these systems, or if you want to build a
524	  generic distribution kernel, say Y here - otherwise say N.
525endif # X86_32
526
527if X86_64
528config X86_EXTENDED_PLATFORM
529	bool "Support for extended (non-PC) x86 platforms"
530	default y
531	help
532	  If you disable this option then the kernel will only support
533	  standard PC platforms. (which covers the vast majority of
534	  systems out there.)
535
536	  If you enable this option then you'll be able to select support
537	  for the following (non-PC) 64 bit x86 platforms:
538		Numascale NumaChip
539		ScaleMP vSMP
540		SGI Ultraviolet
541
542	  If you have one of these systems, or if you want to build a
543	  generic distribution kernel, say Y here - otherwise say N.
544endif # X86_64
545# This is an alphabetically sorted list of 64 bit extended platforms
546# Please maintain the alphabetic order if and when there are additions
547config X86_NUMACHIP
548	bool "Numascale NumaChip"
549	depends on X86_64
550	depends on X86_EXTENDED_PLATFORM
551	depends on NUMA
552	depends on SMP
553	depends on X86_X2APIC
554	depends on PCI_MMCONFIG
555	help
556	  Adds support for Numascale NumaChip large-SMP systems. Needed to
557	  enable more than ~168 cores.
558	  If you don't have one of these, you should say N here.
559
560config X86_VSMP
561	bool "ScaleMP vSMP"
562	select HYPERVISOR_GUEST
563	select PARAVIRT
564	depends on X86_64 && PCI
565	depends on X86_EXTENDED_PLATFORM
566	depends on SMP
567	help
568	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
569	  supposed to run on these EM64T-based machines.  Only choose this option
570	  if you have one of these machines.
571
572config X86_UV
573	bool "SGI Ultraviolet"
574	depends on X86_64
575	depends on X86_EXTENDED_PLATFORM
576	depends on NUMA
577	depends on EFI
578	depends on KEXEC_CORE
579	depends on X86_X2APIC
580	depends on PCI
581	help
582	  This option is needed in order to support SGI Ultraviolet systems.
583	  If you don't have one of these, you should say N here.
584
585# Following is an alphabetically sorted list of 32 bit extended platforms
586# Please maintain the alphabetic order if and when there are additions
587
588config X86_GOLDFISH
589	bool "Goldfish (Virtual Platform)"
590	depends on X86_EXTENDED_PLATFORM
591	help
592	  Enable support for the Goldfish virtual platform used primarily
593	  for Android development. Unless you are building for the Android
594	  Goldfish emulator say N here.
595
596config X86_INTEL_CE
597	bool "CE4100 TV platform"
598	depends on PCI
599	depends on PCI_GODIRECT
600	depends on X86_IO_APIC
601	depends on X86_32
602	depends on X86_EXTENDED_PLATFORM
603	select X86_REBOOTFIXUPS
604	select OF
605	select OF_EARLY_FLATTREE
606	help
607	  Select for the Intel CE media processor (CE4100) SOC.
608	  This option compiles in support for the CE4100 SOC for settop
609	  boxes and media devices.
610
611config X86_INTEL_MID
612	bool "Intel MID platform support"
613	depends on X86_EXTENDED_PLATFORM
614	depends on X86_PLATFORM_DEVICES
615	depends on PCI
616	depends on X86_64 || (PCI_GOANY && X86_32)
617	depends on X86_IO_APIC
618	select I2C
619	select DW_APB_TIMER
620	select INTEL_SCU_PCI
621	help
622	  Select to build a kernel capable of supporting Intel MID (Mobile
623	  Internet Device) platform systems which do not have the PCI legacy
624	  interfaces. If you are building for a PC class system say N here.
625
626	  Intel MID platforms are based on an Intel processor and chipset which
627	  consume less power than most of the x86 derivatives.
628
629config X86_INTEL_QUARK
630	bool "Intel Quark platform support"
631	depends on X86_32
632	depends on X86_EXTENDED_PLATFORM
633	depends on X86_PLATFORM_DEVICES
634	depends on X86_TSC
635	depends on PCI
636	depends on PCI_GOANY
637	depends on X86_IO_APIC
638	select IOSF_MBI
639	select INTEL_IMR
640	select COMMON_CLK
641	help
642	  Select to include support for Quark X1000 SoC.
643	  Say Y here if you have a Quark based system such as the Arduino
644	  compatible Intel Galileo.
645
646config X86_INTEL_LPSS
647	bool "Intel Low Power Subsystem Support"
648	depends on X86 && ACPI && PCI
649	select COMMON_CLK
650	select PINCTRL
651	select IOSF_MBI
652	help
653	  Select to build support for Intel Low Power Subsystem such as
654	  found on Intel Lynxpoint PCH. Selecting this option enables
655	  things like clock tree (common clock framework) and pincontrol
656	  which are needed by the LPSS peripheral drivers.
657
658config X86_AMD_PLATFORM_DEVICE
659	bool "AMD ACPI2Platform devices support"
660	depends on ACPI
661	select COMMON_CLK
662	select PINCTRL
663	help
664	  Select to interpret AMD specific ACPI device to platform device
665	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
666	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
667	  implemented under PINCTRL subsystem.
668
669config IOSF_MBI
670	tristate "Intel SoC IOSF Sideband support for SoC platforms"
671	depends on PCI
672	help
673	  This option enables sideband register access support for Intel SoC
674	  platforms. On these platforms the IOSF sideband is used in lieu of
675	  MSR's for some register accesses, mostly but not limited to thermal
676	  and power. Drivers may query the availability of this device to
677	  determine if they need the sideband in order to work on these
678	  platforms. The sideband is available on the following SoC products.
679	  This list is not meant to be exclusive.
680	   - BayTrail
681	   - Braswell
682	   - Quark
683
684	  You should say Y if you are running a kernel on one of these SoC's.
685
686config IOSF_MBI_DEBUG
687	bool "Enable IOSF sideband access through debugfs"
688	depends on IOSF_MBI && DEBUG_FS
689	help
690	  Select this option to expose the IOSF sideband access registers (MCR,
691	  MDR, MCRX) through debugfs to write and read register information from
692	  different units on the SoC. This is most useful for obtaining device
693	  state information for debug and analysis. As this is a general access
694	  mechanism, users of this option would have specific knowledge of the
695	  device they want to access.
696
697	  If you don't require the option or are in doubt, say N.
698
699config X86_RDC321X
700	bool "RDC R-321x SoC"
701	depends on X86_32
702	depends on X86_EXTENDED_PLATFORM
703	select M486
704	select X86_REBOOTFIXUPS
705	help
706	  This option is needed for RDC R-321x system-on-chip, also known
707	  as R-8610-(G).
708	  If you don't have one of these chips, you should say N here.
709
710config X86_32_NON_STANDARD
711	bool "Support non-standard 32-bit SMP architectures"
712	depends on X86_32 && SMP
713	depends on X86_EXTENDED_PLATFORM
714	help
715	  This option compiles in the bigsmp and STA2X11 default
716	  subarchitectures.  It is intended for a generic binary
717	  kernel. If you select them all, kernel will probe it one by
718	  one and will fallback to default.
719
720# Alphabetically sorted list of Non standard 32 bit platforms
721
722config X86_SUPPORTS_MEMORY_FAILURE
723	def_bool y
724	# MCE code calls memory_failure():
725	depends on X86_MCE
726	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
727	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
728	depends on X86_64 || !SPARSEMEM
729	select ARCH_SUPPORTS_MEMORY_FAILURE
730
731config STA2X11
732	bool "STA2X11 Companion Chip Support"
733	depends on X86_32_NON_STANDARD && PCI
734	select SWIOTLB
735	select MFD_STA2X11
736	select GPIOLIB
737	help
738	  This adds support for boards based on the STA2X11 IO-Hub,
739	  a.k.a. "ConneXt". The chip is used in place of the standard
740	  PC chipset, so all "standard" peripherals are missing. If this
741	  option is selected the kernel will still be able to boot on
742	  standard PC machines.
743
744config X86_32_IRIS
745	tristate "Eurobraille/Iris poweroff module"
746	depends on X86_32
747	help
748	  The Iris machines from EuroBraille do not have APM or ACPI support
749	  to shut themselves down properly.  A special I/O sequence is
750	  needed to do so, which is what this module does at
751	  kernel shutdown.
752
753	  This is only for Iris machines from EuroBraille.
754
755	  If unused, say N.
756
757config SCHED_OMIT_FRAME_POINTER
758	def_bool y
759	prompt "Single-depth WCHAN output"
760	depends on X86
761	help
762	  Calculate simpler /proc/<PID>/wchan values. If this option
763	  is disabled then wchan values will recurse back to the
764	  caller function. This provides more accurate wchan values,
765	  at the expense of slightly more scheduling overhead.
766
767	  If in doubt, say "Y".
768
769menuconfig HYPERVISOR_GUEST
770	bool "Linux guest support"
771	help
772	  Say Y here to enable options for running Linux under various hyper-
773	  visors. This option enables basic hypervisor detection and platform
774	  setup.
775
776	  If you say N, all options in this submenu will be skipped and
777	  disabled, and Linux guest support won't be built in.
778
779if HYPERVISOR_GUEST
780
781config PARAVIRT
782	bool "Enable paravirtualization code"
783	depends on HAVE_STATIC_CALL
784	help
785	  This changes the kernel so it can modify itself when it is run
786	  under a hypervisor, potentially improving performance significantly
787	  over full virtualization.  However, when run without a hypervisor
788	  the kernel is theoretically slower and slightly larger.
789
790config PARAVIRT_XXL
791	bool
792
793config PARAVIRT_DEBUG
794	bool "paravirt-ops debugging"
795	depends on PARAVIRT && DEBUG_KERNEL
796	help
797	  Enable to debug paravirt_ops internals.  Specifically, BUG if
798	  a paravirt_op is missing when it is called.
799
800config PARAVIRT_SPINLOCKS
801	bool "Paravirtualization layer for spinlocks"
802	depends on PARAVIRT && SMP
803	help
804	  Paravirtualized spinlocks allow a pvops backend to replace the
805	  spinlock implementation with something virtualization-friendly
806	  (for example, block the virtual CPU rather than spinning).
807
808	  It has a minimal impact on native kernels and gives a nice performance
809	  benefit on paravirtualized KVM / Xen kernels.
810
811	  If you are unsure how to answer this question, answer Y.
812
813config X86_HV_CALLBACK_VECTOR
814	def_bool n
815
816source "arch/x86/xen/Kconfig"
817
818config KVM_GUEST
819	bool "KVM Guest support (including kvmclock)"
820	depends on PARAVIRT
821	select PARAVIRT_CLOCK
822	select ARCH_CPUIDLE_HALTPOLL
823	select X86_HV_CALLBACK_VECTOR
824	default y
825	help
826	  This option enables various optimizations for running under the KVM
827	  hypervisor. It includes a paravirtualized clock, so that instead
828	  of relying on a PIT (or probably other) emulation by the
829	  underlying device model, the host provides the guest with
830	  timing infrastructure such as time of day, and system time
831
832config ARCH_CPUIDLE_HALTPOLL
833	def_bool n
834	prompt "Disable host haltpoll when loading haltpoll driver"
835	help
836	  If virtualized under KVM, disable host haltpoll.
837
838config PVH
839	bool "Support for running PVH guests"
840	help
841	  This option enables the PVH entry point for guest virtual machines
842	  as specified in the x86/HVM direct boot ABI.
843
844config PARAVIRT_TIME_ACCOUNTING
845	bool "Paravirtual steal time accounting"
846	depends on PARAVIRT
847	help
848	  Select this option to enable fine granularity task steal time
849	  accounting. Time spent executing other tasks in parallel with
850	  the current vCPU is discounted from the vCPU power. To account for
851	  that, there can be a small performance impact.
852
853	  If in doubt, say N here.
854
855config PARAVIRT_CLOCK
856	bool
857
858config JAILHOUSE_GUEST
859	bool "Jailhouse non-root cell support"
860	depends on X86_64 && PCI
861	select X86_PM_TIMER
862	help
863	  This option allows to run Linux as guest in a Jailhouse non-root
864	  cell. You can leave this option disabled if you only want to start
865	  Jailhouse and run Linux afterwards in the root cell.
866
867config ACRN_GUEST
868	bool "ACRN Guest support"
869	depends on X86_64
870	select X86_HV_CALLBACK_VECTOR
871	help
872	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
873	  a flexible, lightweight reference open-source hypervisor, built with
874	  real-time and safety-criticality in mind. It is built for embedded
875	  IOT with small footprint and real-time features. More details can be
876	  found in https://projectacrn.org/.
877
878config INTEL_TDX_GUEST
879	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
880	depends on X86_64 && CPU_SUP_INTEL
881	depends on X86_X2APIC
882	depends on EFI_STUB
883	select ARCH_HAS_CC_PLATFORM
884	select X86_MEM_ENCRYPT
885	select X86_MCE
886	select UNACCEPTED_MEMORY
887	help
888	  Support running as a guest under Intel TDX.  Without this support,
889	  the guest kernel can not boot or run under TDX.
890	  TDX includes memory encryption and integrity capabilities
891	  which protect the confidentiality and integrity of guest
892	  memory contents and CPU state. TDX guests are protected from
893	  some attacks from the VMM.
894
895endif # HYPERVISOR_GUEST
896
897source "arch/x86/Kconfig.cpu"
898
899config HPET_TIMER
900	def_bool X86_64
901	prompt "HPET Timer Support" if X86_32
902	help
903	  Use the IA-PC HPET (High Precision Event Timer) to manage
904	  time in preference to the PIT and RTC, if a HPET is
905	  present.
906	  HPET is the next generation timer replacing legacy 8254s.
907	  The HPET provides a stable time base on SMP
908	  systems, unlike the TSC, but it is more expensive to access,
909	  as it is off-chip.  The interface used is documented
910	  in the HPET spec, revision 1.
911
912	  You can safely choose Y here.  However, HPET will only be
913	  activated if the platform and the BIOS support this feature.
914	  Otherwise the 8254 will be used for timing services.
915
916	  Choose N to continue using the legacy 8254 timer.
917
918config HPET_EMULATE_RTC
919	def_bool y
920	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
921
922# Mark as expert because too many people got it wrong.
923# The code disables itself when not needed.
924config DMI
925	default y
926	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
927	bool "Enable DMI scanning" if EXPERT
928	help
929	  Enabled scanning of DMI to identify machine quirks. Say Y
930	  here unless you have verified that your setup is not
931	  affected by entries in the DMI blacklist. Required by PNP
932	  BIOS code.
933
934config GART_IOMMU
935	bool "Old AMD GART IOMMU support"
936	select DMA_OPS
937	select IOMMU_HELPER
938	select SWIOTLB
939	depends on X86_64 && PCI && AMD_NB
940	help
941	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
942	  GART based hardware IOMMUs.
943
944	  The GART supports full DMA access for devices with 32-bit access
945	  limitations, on systems with more than 3 GB. This is usually needed
946	  for USB, sound, many IDE/SATA chipsets and some other devices.
947
948	  Newer systems typically have a modern AMD IOMMU, supported via
949	  the CONFIG_AMD_IOMMU=y config option.
950
951	  In normal configurations this driver is only active when needed:
952	  there's more than 3 GB of memory and the system contains a
953	  32-bit limited device.
954
955	  If unsure, say Y.
956
957config BOOT_VESA_SUPPORT
958	bool
959	help
960	  If true, at least one selected framebuffer driver can take advantage
961	  of VESA video modes set at an early boot stage via the vga= parameter.
962
963config MAXSMP
964	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
965	depends on X86_64 && SMP && DEBUG_KERNEL
966	select CPUMASK_OFFSTACK
967	help
968	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
969	  If unsure, say N.
970
971#
972# The maximum number of CPUs supported:
973#
974# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
975# and which can be configured interactively in the
976# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
977#
978# The ranges are different on 32-bit and 64-bit kernels, depending on
979# hardware capabilities and scalability features of the kernel.
980#
981# ( If MAXSMP is enabled we just use the highest possible value and disable
982#   interactive configuration. )
983#
984
985config NR_CPUS_RANGE_BEGIN
986	int
987	default NR_CPUS_RANGE_END if MAXSMP
988	default    1 if !SMP
989	default    2
990
991config NR_CPUS_RANGE_END
992	int
993	depends on X86_32
994	default   64 if  SMP &&  X86_BIGSMP
995	default    8 if  SMP && !X86_BIGSMP
996	default    1 if !SMP
997
998config NR_CPUS_RANGE_END
999	int
1000	depends on X86_64
1001	default 8192 if  SMP && CPUMASK_OFFSTACK
1002	default  512 if  SMP && !CPUMASK_OFFSTACK
1003	default    1 if !SMP
1004
1005config NR_CPUS_DEFAULT
1006	int
1007	depends on X86_32
1008	default   32 if  X86_BIGSMP
1009	default    8 if  SMP
1010	default    1 if !SMP
1011
1012config NR_CPUS_DEFAULT
1013	int
1014	depends on X86_64
1015	default 8192 if  MAXSMP
1016	default   64 if  SMP
1017	default    1 if !SMP
1018
1019config NR_CPUS
1020	int "Maximum number of CPUs" if SMP && !MAXSMP
1021	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1022	default NR_CPUS_DEFAULT
1023	help
1024	  This allows you to specify the maximum number of CPUs which this
1025	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1026	  supported value is 8192, otherwise the maximum value is 512.  The
1027	  minimum value which makes sense is 2.
1028
1029	  This is purely to save memory: each supported CPU adds about 8KB
1030	  to the kernel image.
1031
1032config SCHED_CLUSTER
1033	bool "Cluster scheduler support"
1034	depends on SMP
1035	default y
1036	help
1037	  Cluster scheduler support improves the CPU scheduler's decision
1038	  making when dealing with machines that have clusters of CPUs.
1039	  Cluster usually means a couple of CPUs which are placed closely
1040	  by sharing mid-level caches, last-level cache tags or internal
1041	  busses.
1042
1043config SCHED_SMT
1044	def_bool y if SMP
1045
1046config SCHED_MC
1047	def_bool y
1048	prompt "Multi-core scheduler support"
1049	depends on SMP
1050	help
1051	  Multi-core scheduler support improves the CPU scheduler's decision
1052	  making when dealing with multi-core CPU chips at a cost of slightly
1053	  increased overhead in some places. If unsure say N here.
1054
1055config SCHED_MC_PRIO
1056	bool "CPU core priorities scheduler support"
1057	depends on SCHED_MC && CPU_SUP_INTEL
1058	select X86_INTEL_PSTATE
1059	select CPU_FREQ
1060	default y
1061	help
1062	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1063	  core ordering determined at manufacturing time, which allows
1064	  certain cores to reach higher turbo frequencies (when running
1065	  single threaded workloads) than others.
1066
1067	  Enabling this kernel feature teaches the scheduler about
1068	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1069	  scheduler's CPU selection logic accordingly, so that higher
1070	  overall system performance can be achieved.
1071
1072	  This feature will have no effect on CPUs without this feature.
1073
1074	  If unsure say Y here.
1075
1076config UP_LATE_INIT
1077	def_bool y
1078	depends on !SMP && X86_LOCAL_APIC
1079
1080config X86_UP_APIC
1081	bool "Local APIC support on uniprocessors" if !PCI_MSI
1082	default PCI_MSI
1083	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1084	help
1085	  A local APIC (Advanced Programmable Interrupt Controller) is an
1086	  integrated interrupt controller in the CPU. If you have a single-CPU
1087	  system which has a processor with a local APIC, you can say Y here to
1088	  enable and use it. If you say Y here even though your machine doesn't
1089	  have a local APIC, then the kernel will still run with no slowdown at
1090	  all. The local APIC supports CPU-generated self-interrupts (timer,
1091	  performance counters), and the NMI watchdog which detects hard
1092	  lockups.
1093
1094config X86_UP_IOAPIC
1095	bool "IO-APIC support on uniprocessors"
1096	depends on X86_UP_APIC
1097	help
1098	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1099	  SMP-capable replacement for PC-style interrupt controllers. Most
1100	  SMP systems and many recent uniprocessor systems have one.
1101
1102	  If you have a single-CPU system with an IO-APIC, you can say Y here
1103	  to use it. If you say Y here even though your machine doesn't have
1104	  an IO-APIC, then the kernel will still run with no slowdown at all.
1105
1106config X86_LOCAL_APIC
1107	def_bool y
1108	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1109	select IRQ_DOMAIN_HIERARCHY
1110
1111config X86_IO_APIC
1112	def_bool y
1113	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1114
1115config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1116	bool "Reroute for broken boot IRQs"
1117	depends on X86_IO_APIC
1118	help
1119	  This option enables a workaround that fixes a source of
1120	  spurious interrupts. This is recommended when threaded
1121	  interrupt handling is used on systems where the generation of
1122	  superfluous "boot interrupts" cannot be disabled.
1123
1124	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1125	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1126	  kernel does during interrupt handling). On chipsets where this
1127	  boot IRQ generation cannot be disabled, this workaround keeps
1128	  the original IRQ line masked so that only the equivalent "boot
1129	  IRQ" is delivered to the CPUs. The workaround also tells the
1130	  kernel to set up the IRQ handler on the boot IRQ line. In this
1131	  way only one interrupt is delivered to the kernel. Otherwise
1132	  the spurious second interrupt may cause the kernel to bring
1133	  down (vital) interrupt lines.
1134
1135	  Only affects "broken" chipsets. Interrupt sharing may be
1136	  increased on these systems.
1137
1138config X86_MCE
1139	bool "Machine Check / overheating reporting"
1140	select GENERIC_ALLOCATOR
1141	default y
1142	help
1143	  Machine Check support allows the processor to notify the
1144	  kernel if it detects a problem (e.g. overheating, data corruption).
1145	  The action the kernel takes depends on the severity of the problem,
1146	  ranging from warning messages to halting the machine.
1147
1148config X86_MCELOG_LEGACY
1149	bool "Support for deprecated /dev/mcelog character device"
1150	depends on X86_MCE
1151	help
1152	  Enable support for /dev/mcelog which is needed by the old mcelog
1153	  userspace logging daemon. Consider switching to the new generation
1154	  rasdaemon solution.
1155
1156config X86_MCE_INTEL
1157	def_bool y
1158	prompt "Intel MCE features"
1159	depends on X86_MCE && X86_LOCAL_APIC
1160	help
1161	  Additional support for intel specific MCE features such as
1162	  the thermal monitor.
1163
1164config X86_MCE_AMD
1165	def_bool y
1166	prompt "AMD MCE features"
1167	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1168	help
1169	  Additional support for AMD specific MCE features such as
1170	  the DRAM Error Threshold.
1171
1172config X86_ANCIENT_MCE
1173	bool "Support for old Pentium 5 / WinChip machine checks"
1174	depends on X86_32 && X86_MCE
1175	help
1176	  Include support for machine check handling on old Pentium 5 or WinChip
1177	  systems. These typically need to be enabled explicitly on the command
1178	  line.
1179
1180config X86_MCE_THRESHOLD
1181	depends on X86_MCE_AMD || X86_MCE_INTEL
1182	def_bool y
1183
1184config X86_MCE_INJECT
1185	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1186	tristate "Machine check injector support"
1187	help
1188	  Provide support for injecting machine checks for testing purposes.
1189	  If you don't know what a machine check is and you don't do kernel
1190	  QA it is safe to say n.
1191
1192source "arch/x86/events/Kconfig"
1193
1194config X86_LEGACY_VM86
1195	bool "Legacy VM86 support"
1196	depends on X86_32
1197	help
1198	  This option allows user programs to put the CPU into V8086
1199	  mode, which is an 80286-era approximation of 16-bit real mode.
1200
1201	  Some very old versions of X and/or vbetool require this option
1202	  for user mode setting.  Similarly, DOSEMU will use it if
1203	  available to accelerate real mode DOS programs.  However, any
1204	  recent version of DOSEMU, X, or vbetool should be fully
1205	  functional even without kernel VM86 support, as they will all
1206	  fall back to software emulation. Nevertheless, if you are using
1207	  a 16-bit DOS program where 16-bit performance matters, vm86
1208	  mode might be faster than emulation and you might want to
1209	  enable this option.
1210
1211	  Note that any app that works on a 64-bit kernel is unlikely to
1212	  need this option, as 64-bit kernels don't, and can't, support
1213	  V8086 mode. This option is also unrelated to 16-bit protected
1214	  mode and is not needed to run most 16-bit programs under Wine.
1215
1216	  Enabling this option increases the complexity of the kernel
1217	  and slows down exception handling a tiny bit.
1218
1219	  If unsure, say N here.
1220
1221config VM86
1222	bool
1223	default X86_LEGACY_VM86
1224
1225config X86_16BIT
1226	bool "Enable support for 16-bit segments" if EXPERT
1227	default y
1228	depends on MODIFY_LDT_SYSCALL
1229	help
1230	  This option is required by programs like Wine to run 16-bit
1231	  protected mode legacy code on x86 processors.  Disabling
1232	  this option saves about 300 bytes on i386, or around 6K text
1233	  plus 16K runtime memory on x86-64,
1234
1235config X86_ESPFIX32
1236	def_bool y
1237	depends on X86_16BIT && X86_32
1238
1239config X86_ESPFIX64
1240	def_bool y
1241	depends on X86_16BIT && X86_64
1242
1243config X86_VSYSCALL_EMULATION
1244	bool "Enable vsyscall emulation" if EXPERT
1245	default y
1246	depends on X86_64
1247	help
1248	  This enables emulation of the legacy vsyscall page.  Disabling
1249	  it is roughly equivalent to booting with vsyscall=none, except
1250	  that it will also disable the helpful warning if a program
1251	  tries to use a vsyscall.  With this option set to N, offending
1252	  programs will just segfault, citing addresses of the form
1253	  0xffffffffff600?00.
1254
1255	  This option is required by many programs built before 2013, and
1256	  care should be used even with newer programs if set to N.
1257
1258	  Disabling this option saves about 7K of kernel size and
1259	  possibly 4K of additional runtime pagetable memory.
1260
1261config X86_IOPL_IOPERM
1262	bool "IOPERM and IOPL Emulation"
1263	default y
1264	help
1265	  This enables the ioperm() and iopl() syscalls which are necessary
1266	  for legacy applications.
1267
1268	  Legacy IOPL support is an overbroad mechanism which allows user
1269	  space aside of accessing all 65536 I/O ports also to disable
1270	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1271	  capabilities and permission from potentially active security
1272	  modules.
1273
1274	  The emulation restricts the functionality of the syscall to
1275	  only allowing the full range I/O port access, but prevents the
1276	  ability to disable interrupts from user space which would be
1277	  granted if the hardware IOPL mechanism would be used.
1278
1279config TOSHIBA
1280	tristate "Toshiba Laptop support"
1281	depends on X86_32
1282	help
1283	  This adds a driver to safely access the System Management Mode of
1284	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1285	  not work on models with a Phoenix BIOS. The System Management Mode
1286	  is used to set the BIOS and power saving options on Toshiba portables.
1287
1288	  For information on utilities to make use of this driver see the
1289	  Toshiba Linux utilities web site at:
1290	  <http://www.buzzard.org.uk/toshiba/>.
1291
1292	  Say Y if you intend to run this kernel on a Toshiba portable.
1293	  Say N otherwise.
1294
1295config X86_REBOOTFIXUPS
1296	bool "Enable X86 board specific fixups for reboot"
1297	depends on X86_32
1298	help
1299	  This enables chipset and/or board specific fixups to be done
1300	  in order to get reboot to work correctly. This is only needed on
1301	  some combinations of hardware and BIOS. The symptom, for which
1302	  this config is intended, is when reboot ends with a stalled/hung
1303	  system.
1304
1305	  Currently, the only fixup is for the Geode machines using
1306	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1307
1308	  Say Y if you want to enable the fixup. Currently, it's safe to
1309	  enable this option even if you don't need it.
1310	  Say N otherwise.
1311
1312config MICROCODE
1313	def_bool y
1314	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1315
1316config MICROCODE_LATE_LOADING
1317	bool "Late microcode loading (DANGEROUS)"
1318	default n
1319	depends on MICROCODE
1320	help
1321	  Loading microcode late, when the system is up and executing instructions
1322	  is a tricky business and should be avoided if possible. Just the sequence
1323	  of synchronizing all cores and SMT threads is one fragile dance which does
1324	  not guarantee that cores might not softlock after the loading. Therefore,
1325	  use this at your own risk. Late loading taints the kernel too.
1326
1327config X86_MSR
1328	tristate "/dev/cpu/*/msr - Model-specific register support"
1329	help
1330	  This device gives privileged processes access to the x86
1331	  Model-Specific Registers (MSRs).  It is a character device with
1332	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1333	  MSR accesses are directed to a specific CPU on multi-processor
1334	  systems.
1335
1336config X86_CPUID
1337	tristate "/dev/cpu/*/cpuid - CPU information support"
1338	help
1339	  This device gives processes access to the x86 CPUID instruction to
1340	  be executed on a specific processor.  It is a character device
1341	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1342	  /dev/cpu/31/cpuid.
1343
1344choice
1345	prompt "High Memory Support"
1346	default HIGHMEM4G
1347	depends on X86_32
1348
1349config NOHIGHMEM
1350	bool "off"
1351	help
1352	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1353	  However, the address space of 32-bit x86 processors is only 4
1354	  Gigabytes large. That means that, if you have a large amount of
1355	  physical memory, not all of it can be "permanently mapped" by the
1356	  kernel. The physical memory that's not permanently mapped is called
1357	  "high memory".
1358
1359	  If you are compiling a kernel which will never run on a machine with
1360	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1361	  choice and suitable for most users). This will result in a "3GB/1GB"
1362	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1363	  space and the remaining part of the 4GB virtual memory space is used
1364	  by the kernel to permanently map as much physical memory as
1365	  possible.
1366
1367	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1368	  answer "4GB" here.
1369
1370	  If more than 4 Gigabytes is used then answer "64GB" here. This
1371	  selection turns Intel PAE (Physical Address Extension) mode on.
1372	  PAE implements 3-level paging on IA32 processors. PAE is fully
1373	  supported by Linux, PAE mode is implemented on all recent Intel
1374	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1375	  then the kernel will not boot on CPUs that don't support PAE!
1376
1377	  The actual amount of total physical memory will either be
1378	  auto detected or can be forced by using a kernel command line option
1379	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1380	  your boot loader (lilo or loadlin) about how to pass options to the
1381	  kernel at boot time.)
1382
1383	  If unsure, say "off".
1384
1385config HIGHMEM4G
1386	bool "4GB"
1387	help
1388	  Select this if you have a 32-bit processor and between 1 and 4
1389	  gigabytes of physical RAM.
1390
1391config HIGHMEM64G
1392	bool "64GB"
1393	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1394	select X86_PAE
1395	help
1396	  Select this if you have a 32-bit processor and more than 4
1397	  gigabytes of physical RAM.
1398
1399endchoice
1400
1401choice
1402	prompt "Memory split" if EXPERT
1403	default VMSPLIT_3G
1404	depends on X86_32
1405	help
1406	  Select the desired split between kernel and user memory.
1407
1408	  If the address range available to the kernel is less than the
1409	  physical memory installed, the remaining memory will be available
1410	  as "high memory". Accessing high memory is a little more costly
1411	  than low memory, as it needs to be mapped into the kernel first.
1412	  Note that increasing the kernel address space limits the range
1413	  available to user programs, making the address space there
1414	  tighter.  Selecting anything other than the default 3G/1G split
1415	  will also likely make your kernel incompatible with binary-only
1416	  kernel modules.
1417
1418	  If you are not absolutely sure what you are doing, leave this
1419	  option alone!
1420
1421	config VMSPLIT_3G
1422		bool "3G/1G user/kernel split"
1423	config VMSPLIT_3G_OPT
1424		depends on !X86_PAE
1425		bool "3G/1G user/kernel split (for full 1G low memory)"
1426	config VMSPLIT_2G
1427		bool "2G/2G user/kernel split"
1428	config VMSPLIT_2G_OPT
1429		depends on !X86_PAE
1430		bool "2G/2G user/kernel split (for full 2G low memory)"
1431	config VMSPLIT_1G
1432		bool "1G/3G user/kernel split"
1433endchoice
1434
1435config PAGE_OFFSET
1436	hex
1437	default 0xB0000000 if VMSPLIT_3G_OPT
1438	default 0x80000000 if VMSPLIT_2G
1439	default 0x78000000 if VMSPLIT_2G_OPT
1440	default 0x40000000 if VMSPLIT_1G
1441	default 0xC0000000
1442	depends on X86_32
1443
1444config HIGHMEM
1445	def_bool y
1446	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1447
1448config X86_PAE
1449	bool "PAE (Physical Address Extension) Support"
1450	depends on X86_32 && !HIGHMEM4G
1451	select PHYS_ADDR_T_64BIT
1452	select SWIOTLB
1453	help
1454	  PAE is required for NX support, and furthermore enables
1455	  larger swapspace support for non-overcommit purposes. It
1456	  has the cost of more pagetable lookup overhead, and also
1457	  consumes more pagetable space per process.
1458
1459config X86_5LEVEL
1460	bool "Enable 5-level page tables support"
1461	default y
1462	select DYNAMIC_MEMORY_LAYOUT
1463	select SPARSEMEM_VMEMMAP
1464	depends on X86_64
1465	help
1466	  5-level paging enables access to larger address space:
1467	  up to 128 PiB of virtual address space and 4 PiB of
1468	  physical address space.
1469
1470	  It will be supported by future Intel CPUs.
1471
1472	  A kernel with the option enabled can be booted on machines that
1473	  support 4- or 5-level paging.
1474
1475	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1476	  information.
1477
1478	  Say N if unsure.
1479
1480config X86_DIRECT_GBPAGES
1481	def_bool y
1482	depends on X86_64
1483	help
1484	  Certain kernel features effectively disable kernel
1485	  linear 1 GB mappings (even if the CPU otherwise
1486	  supports them), so don't confuse the user by printing
1487	  that we have them enabled.
1488
1489config X86_CPA_STATISTICS
1490	bool "Enable statistic for Change Page Attribute"
1491	depends on DEBUG_FS
1492	help
1493	  Expose statistics about the Change Page Attribute mechanism, which
1494	  helps to determine the effectiveness of preserving large and huge
1495	  page mappings when mapping protections are changed.
1496
1497config X86_MEM_ENCRYPT
1498	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1499	select DYNAMIC_PHYSICAL_MASK
1500	def_bool n
1501
1502config AMD_MEM_ENCRYPT
1503	bool "AMD Secure Memory Encryption (SME) support"
1504	depends on X86_64 && CPU_SUP_AMD
1505	depends on EFI_STUB
1506	select DMA_COHERENT_POOL
1507	select ARCH_USE_MEMREMAP_PROT
1508	select INSTRUCTION_DECODER
1509	select ARCH_HAS_CC_PLATFORM
1510	select X86_MEM_ENCRYPT
1511	select UNACCEPTED_MEMORY
1512	help
1513	  Say yes to enable support for the encryption of system memory.
1514	  This requires an AMD processor that supports Secure Memory
1515	  Encryption (SME).
1516
1517config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1518	bool "Activate AMD Secure Memory Encryption (SME) by default"
1519	depends on AMD_MEM_ENCRYPT
1520	help
1521	  Say yes to have system memory encrypted by default if running on
1522	  an AMD processor that supports Secure Memory Encryption (SME).
1523
1524	  If set to Y, then the encryption of system memory can be
1525	  deactivated with the mem_encrypt=off command line option.
1526
1527	  If set to N, then the encryption of system memory can be
1528	  activated with the mem_encrypt=on command line option.
1529
1530# Common NUMA Features
1531config NUMA
1532	bool "NUMA Memory Allocation and Scheduler Support"
1533	depends on SMP
1534	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1535	default y if X86_BIGSMP
1536	select USE_PERCPU_NUMA_NODE_ID
1537	help
1538	  Enable NUMA (Non-Uniform Memory Access) support.
1539
1540	  The kernel will try to allocate memory used by a CPU on the
1541	  local memory controller of the CPU and add some more
1542	  NUMA awareness to the kernel.
1543
1544	  For 64-bit this is recommended if the system is Intel Core i7
1545	  (or later), AMD Opteron, or EM64T NUMA.
1546
1547	  For 32-bit this is only needed if you boot a 32-bit
1548	  kernel on a 64-bit NUMA platform.
1549
1550	  Otherwise, you should say N.
1551
1552config AMD_NUMA
1553	def_bool y
1554	prompt "Old style AMD Opteron NUMA detection"
1555	depends on X86_64 && NUMA && PCI
1556	help
1557	  Enable AMD NUMA node topology detection.  You should say Y here if
1558	  you have a multi processor AMD system. This uses an old method to
1559	  read the NUMA configuration directly from the builtin Northbridge
1560	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1561	  which also takes priority if both are compiled in.
1562
1563config X86_64_ACPI_NUMA
1564	def_bool y
1565	prompt "ACPI NUMA detection"
1566	depends on X86_64 && NUMA && ACPI && PCI
1567	select ACPI_NUMA
1568	help
1569	  Enable ACPI SRAT based node topology detection.
1570
1571config NUMA_EMU
1572	bool "NUMA emulation"
1573	depends on NUMA
1574	help
1575	  Enable NUMA emulation. A flat machine will be split
1576	  into virtual nodes when booted with "numa=fake=N", where N is the
1577	  number of nodes. This is only useful for debugging.
1578
1579config NODES_SHIFT
1580	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1581	range 1 10
1582	default "10" if MAXSMP
1583	default "6" if X86_64
1584	default "3"
1585	depends on NUMA
1586	help
1587	  Specify the maximum number of NUMA Nodes available on the target
1588	  system.  Increases memory reserved to accommodate various tables.
1589
1590config ARCH_FLATMEM_ENABLE
1591	def_bool y
1592	depends on X86_32 && !NUMA
1593
1594config ARCH_SPARSEMEM_ENABLE
1595	def_bool y
1596	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1597	select SPARSEMEM_STATIC if X86_32
1598	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1599
1600config ARCH_SPARSEMEM_DEFAULT
1601	def_bool X86_64 || (NUMA && X86_32)
1602
1603config ARCH_SELECT_MEMORY_MODEL
1604	def_bool y
1605	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1606
1607config ARCH_MEMORY_PROBE
1608	bool "Enable sysfs memory/probe interface"
1609	depends on MEMORY_HOTPLUG
1610	help
1611	  This option enables a sysfs memory/probe interface for testing.
1612	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1613	  If you are unsure how to answer this question, answer N.
1614
1615config ARCH_PROC_KCORE_TEXT
1616	def_bool y
1617	depends on X86_64 && PROC_KCORE
1618
1619config ILLEGAL_POINTER_VALUE
1620	hex
1621	default 0 if X86_32
1622	default 0xdead000000000000 if X86_64
1623
1624config X86_PMEM_LEGACY_DEVICE
1625	bool
1626
1627config X86_PMEM_LEGACY
1628	tristate "Support non-standard NVDIMMs and ADR protected memory"
1629	depends on PHYS_ADDR_T_64BIT
1630	depends on BLK_DEV
1631	select X86_PMEM_LEGACY_DEVICE
1632	select NUMA_KEEP_MEMINFO if NUMA
1633	select LIBNVDIMM
1634	help
1635	  Treat memory marked using the non-standard e820 type of 12 as used
1636	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1637	  The kernel will offer these regions to the 'pmem' driver so
1638	  they can be used for persistent storage.
1639
1640	  Say Y if unsure.
1641
1642config HIGHPTE
1643	bool "Allocate 3rd-level pagetables from highmem"
1644	depends on HIGHMEM
1645	help
1646	  The VM uses one page table entry for each page of physical memory.
1647	  For systems with a lot of RAM, this can be wasteful of precious
1648	  low memory.  Setting this option will put user-space page table
1649	  entries in high memory.
1650
1651config X86_CHECK_BIOS_CORRUPTION
1652	bool "Check for low memory corruption"
1653	help
1654	  Periodically check for memory corruption in low memory, which
1655	  is suspected to be caused by BIOS.  Even when enabled in the
1656	  configuration, it is disabled at runtime.  Enable it by
1657	  setting "memory_corruption_check=1" on the kernel command
1658	  line.  By default it scans the low 64k of memory every 60
1659	  seconds; see the memory_corruption_check_size and
1660	  memory_corruption_check_period parameters in
1661	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1662
1663	  When enabled with the default parameters, this option has
1664	  almost no overhead, as it reserves a relatively small amount
1665	  of memory and scans it infrequently.  It both detects corruption
1666	  and prevents it from affecting the running system.
1667
1668	  It is, however, intended as a diagnostic tool; if repeatable
1669	  BIOS-originated corruption always affects the same memory,
1670	  you can use memmap= to prevent the kernel from using that
1671	  memory.
1672
1673config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1674	bool "Set the default setting of memory_corruption_check"
1675	depends on X86_CHECK_BIOS_CORRUPTION
1676	default y
1677	help
1678	  Set whether the default state of memory_corruption_check is
1679	  on or off.
1680
1681config MATH_EMULATION
1682	bool
1683	depends on MODIFY_LDT_SYSCALL
1684	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1685	help
1686	  Linux can emulate a math coprocessor (used for floating point
1687	  operations) if you don't have one. 486DX and Pentium processors have
1688	  a math coprocessor built in, 486SX and 386 do not, unless you added
1689	  a 487DX or 387, respectively. (The messages during boot time can
1690	  give you some hints here ["man dmesg"].) Everyone needs either a
1691	  coprocessor or this emulation.
1692
1693	  If you don't have a math coprocessor, you need to say Y here; if you
1694	  say Y here even though you have a coprocessor, the coprocessor will
1695	  be used nevertheless. (This behavior can be changed with the kernel
1696	  command line option "no387", which comes handy if your coprocessor
1697	  is broken. Try "man bootparam" or see the documentation of your boot
1698	  loader (lilo or loadlin) about how to pass options to the kernel at
1699	  boot time.) This means that it is a good idea to say Y here if you
1700	  intend to use this kernel on different machines.
1701
1702	  More information about the internals of the Linux math coprocessor
1703	  emulation can be found in <file:arch/x86/math-emu/README>.
1704
1705	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1706	  kernel, it won't hurt.
1707
1708config MTRR
1709	def_bool y
1710	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1711	help
1712	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1713	  the Memory Type Range Registers (MTRRs) may be used to control
1714	  processor access to memory ranges. This is most useful if you have
1715	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1716	  allows bus write transfers to be combined into a larger transfer
1717	  before bursting over the PCI/AGP bus. This can increase performance
1718	  of image write operations 2.5 times or more. Saying Y here creates a
1719	  /proc/mtrr file which may be used to manipulate your processor's
1720	  MTRRs. Typically the X server should use this.
1721
1722	  This code has a reasonably generic interface so that similar
1723	  control registers on other processors can be easily supported
1724	  as well:
1725
1726	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1727	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1728	  these, the ARRs are used to emulate the MTRRs.
1729	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1730	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1731	  write-combining. All of these processors are supported by this code
1732	  and it makes sense to say Y here if you have one of them.
1733
1734	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1735	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1736	  can lead to all sorts of problems, so it's good to say Y here.
1737
1738	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1739	  just add about 9 KB to your kernel.
1740
1741	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1742
1743config MTRR_SANITIZER
1744	def_bool y
1745	prompt "MTRR cleanup support"
1746	depends on MTRR
1747	help
1748	  Convert MTRR layout from continuous to discrete, so X drivers can
1749	  add writeback entries.
1750
1751	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1752	  The largest mtrr entry size for a continuous block can be set with
1753	  mtrr_chunk_size.
1754
1755	  If unsure, say Y.
1756
1757config MTRR_SANITIZER_ENABLE_DEFAULT
1758	int "MTRR cleanup enable value (0-1)"
1759	range 0 1
1760	default "0"
1761	depends on MTRR_SANITIZER
1762	help
1763	  Enable mtrr cleanup default value
1764
1765config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1766	int "MTRR cleanup spare reg num (0-7)"
1767	range 0 7
1768	default "1"
1769	depends on MTRR_SANITIZER
1770	help
1771	  mtrr cleanup spare entries default, it can be changed via
1772	  mtrr_spare_reg_nr=N on the kernel command line.
1773
1774config X86_PAT
1775	def_bool y
1776	prompt "x86 PAT support" if EXPERT
1777	depends on MTRR
1778	help
1779	  Use PAT attributes to setup page level cache control.
1780
1781	  PATs are the modern equivalents of MTRRs and are much more
1782	  flexible than MTRRs.
1783
1784	  Say N here if you see bootup problems (boot crash, boot hang,
1785	  spontaneous reboots) or a non-working video driver.
1786
1787	  If unsure, say Y.
1788
1789config ARCH_USES_PG_UNCACHED
1790	def_bool y
1791	depends on X86_PAT
1792
1793config X86_UMIP
1794	def_bool y
1795	prompt "User Mode Instruction Prevention" if EXPERT
1796	help
1797	  User Mode Instruction Prevention (UMIP) is a security feature in
1798	  some x86 processors. If enabled, a general protection fault is
1799	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1800	  executed in user mode. These instructions unnecessarily expose
1801	  information about the hardware state.
1802
1803	  The vast majority of applications do not use these instructions.
1804	  For the very few that do, software emulation is provided in
1805	  specific cases in protected and virtual-8086 modes. Emulated
1806	  results are dummy.
1807
1808config CC_HAS_IBT
1809	# GCC >= 9 and binutils >= 2.29
1810	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1811	# Clang/LLVM >= 14
1812	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1813	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1814	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1815		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1816		  $(as-instr,endbr64)
1817
1818config X86_CET
1819	def_bool n
1820	help
1821	  CET features configured (Shadow stack or IBT)
1822
1823config X86_KERNEL_IBT
1824	prompt "Indirect Branch Tracking"
1825	def_bool y
1826	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1827	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1828	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1829	select OBJTOOL
1830	select X86_CET
1831	help
1832	  Build the kernel with support for Indirect Branch Tracking, a
1833	  hardware support course-grain forward-edge Control Flow Integrity
1834	  protection. It enforces that all indirect calls must land on
1835	  an ENDBR instruction, as such, the compiler will instrument the
1836	  code with them to make this happen.
1837
1838	  In addition to building the kernel with IBT, seal all functions that
1839	  are not indirect call targets, avoiding them ever becoming one.
1840
1841	  This requires LTO like objtool runs and will slow down the build. It
1842	  does significantly reduce the number of ENDBR instructions in the
1843	  kernel image.
1844
1845config X86_INTEL_MEMORY_PROTECTION_KEYS
1846	prompt "Memory Protection Keys"
1847	def_bool y
1848	# Note: only available in 64-bit mode
1849	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1850	select ARCH_USES_HIGH_VMA_FLAGS
1851	select ARCH_HAS_PKEYS
1852	help
1853	  Memory Protection Keys provides a mechanism for enforcing
1854	  page-based protections, but without requiring modification of the
1855	  page tables when an application changes protection domains.
1856
1857	  For details, see Documentation/core-api/protection-keys.rst
1858
1859	  If unsure, say y.
1860
1861choice
1862	prompt "TSX enable mode"
1863	depends on CPU_SUP_INTEL
1864	default X86_INTEL_TSX_MODE_OFF
1865	help
1866	  Intel's TSX (Transactional Synchronization Extensions) feature
1867	  allows to optimize locking protocols through lock elision which
1868	  can lead to a noticeable performance boost.
1869
1870	  On the other hand it has been shown that TSX can be exploited
1871	  to form side channel attacks (e.g. TAA) and chances are there
1872	  will be more of those attacks discovered in the future.
1873
1874	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1875	  might override this decision by tsx=on the command line parameter.
1876	  Even with TSX enabled, the kernel will attempt to enable the best
1877	  possible TAA mitigation setting depending on the microcode available
1878	  for the particular machine.
1879
1880	  This option allows to set the default tsx mode between tsx=on, =off
1881	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1882	  details.
1883
1884	  Say off if not sure, auto if TSX is in use but it should be used on safe
1885	  platforms or on if TSX is in use and the security aspect of tsx is not
1886	  relevant.
1887
1888config X86_INTEL_TSX_MODE_OFF
1889	bool "off"
1890	help
1891	  TSX is disabled if possible - equals to tsx=off command line parameter.
1892
1893config X86_INTEL_TSX_MODE_ON
1894	bool "on"
1895	help
1896	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1897	  line parameter.
1898
1899config X86_INTEL_TSX_MODE_AUTO
1900	bool "auto"
1901	help
1902	  TSX is enabled on TSX capable HW that is believed to be safe against
1903	  side channel attacks- equals the tsx=auto command line parameter.
1904endchoice
1905
1906config X86_SGX
1907	bool "Software Guard eXtensions (SGX)"
1908	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1909	depends on CRYPTO=y
1910	depends on CRYPTO_SHA256=y
1911	select MMU_NOTIFIER
1912	select NUMA_KEEP_MEMINFO if NUMA
1913	select XARRAY_MULTI
1914	help
1915	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1916	  that can be used by applications to set aside private regions of code
1917	  and data, referred to as enclaves. An enclave's private memory can
1918	  only be accessed by code running within the enclave. Accesses from
1919	  outside the enclave, including other enclaves, are disallowed by
1920	  hardware.
1921
1922	  If unsure, say N.
1923
1924config X86_USER_SHADOW_STACK
1925	bool "X86 userspace shadow stack"
1926	depends on AS_WRUSS
1927	depends on X86_64
1928	select ARCH_USES_HIGH_VMA_FLAGS
1929	select X86_CET
1930	help
1931	  Shadow stack protection is a hardware feature that detects function
1932	  return address corruption.  This helps mitigate ROP attacks.
1933	  Applications must be enabled to use it, and old userspace does not
1934	  get protection "for free".
1935
1936	  CPUs supporting shadow stacks were first released in 2020.
1937
1938	  See Documentation/arch/x86/shstk.rst for more information.
1939
1940	  If unsure, say N.
1941
1942config EFI
1943	bool "EFI runtime service support"
1944	depends on ACPI
1945	select UCS2_STRING
1946	select EFI_RUNTIME_WRAPPERS
1947	select ARCH_USE_MEMREMAP_PROT
1948	select EFI_RUNTIME_MAP if KEXEC_CORE
1949	help
1950	  This enables the kernel to use EFI runtime services that are
1951	  available (such as the EFI variable services).
1952
1953	  This option is only useful on systems that have EFI firmware.
1954	  In addition, you should use the latest ELILO loader available
1955	  at <http://elilo.sourceforge.net> in order to take advantage
1956	  of EFI runtime services. However, even with this option, the
1957	  resultant kernel should continue to boot on existing non-EFI
1958	  platforms.
1959
1960config EFI_STUB
1961	bool "EFI stub support"
1962	depends on EFI
1963	select RELOCATABLE
1964	help
1965	  This kernel feature allows a bzImage to be loaded directly
1966	  by EFI firmware without the use of a bootloader.
1967
1968	  See Documentation/admin-guide/efi-stub.rst for more information.
1969
1970config EFI_HANDOVER_PROTOCOL
1971	bool "EFI handover protocol (DEPRECATED)"
1972	depends on EFI_STUB
1973	default y
1974	help
1975	  Select this in order to include support for the deprecated EFI
1976	  handover protocol, which defines alternative entry points into the
1977	  EFI stub.  This is a practice that has no basis in the UEFI
1978	  specification, and requires a priori knowledge on the part of the
1979	  bootloader about Linux/x86 specific ways of passing the command line
1980	  and initrd, and where in memory those assets may be loaded.
1981
1982	  If in doubt, say Y. Even though the corresponding support is not
1983	  present in upstream GRUB or other bootloaders, most distros build
1984	  GRUB with numerous downstream patches applied, and may rely on the
1985	  handover protocol as as result.
1986
1987config EFI_MIXED
1988	bool "EFI mixed-mode support"
1989	depends on EFI_STUB && X86_64
1990	help
1991	  Enabling this feature allows a 64-bit kernel to be booted
1992	  on a 32-bit firmware, provided that your CPU supports 64-bit
1993	  mode.
1994
1995	  Note that it is not possible to boot a mixed-mode enabled
1996	  kernel via the EFI boot stub - a bootloader that supports
1997	  the EFI handover protocol must be used.
1998
1999	  If unsure, say N.
2000
2001config EFI_FAKE_MEMMAP
2002	bool "Enable EFI fake memory map"
2003	depends on EFI
2004	help
2005	  Saying Y here will enable "efi_fake_mem" boot option.  By specifying
2006	  this parameter, you can add arbitrary attribute to specific memory
2007	  range by updating original (firmware provided) EFI memmap.  This is
2008	  useful for debugging of EFI memmap related feature, e.g., Address
2009	  Range Mirroring feature.
2010
2011config EFI_MAX_FAKE_MEM
2012	int "maximum allowable number of ranges in efi_fake_mem boot option"
2013	depends on EFI_FAKE_MEMMAP
2014	range 1 128
2015	default 8
2016	help
2017	  Maximum allowable number of ranges in efi_fake_mem boot option.
2018	  Ranges can be set up to this value using comma-separated list.
2019	  The default value is 8.
2020
2021config EFI_RUNTIME_MAP
2022	bool "Export EFI runtime maps to sysfs" if EXPERT
2023	depends on EFI
2024	help
2025	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2026	  That memory map is required by the 2nd kernel to set up EFI virtual
2027	  mappings after kexec, but can also be used for debugging purposes.
2028
2029	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2030
2031source "kernel/Kconfig.hz"
2032
2033config ARCH_SUPPORTS_KEXEC
2034	def_bool y
2035
2036config ARCH_SUPPORTS_KEXEC_FILE
2037	def_bool X86_64
2038
2039config ARCH_SELECTS_KEXEC_FILE
2040	def_bool y
2041	depends on KEXEC_FILE
2042	select HAVE_IMA_KEXEC if IMA
2043
2044config ARCH_SUPPORTS_KEXEC_PURGATORY
2045	def_bool y
2046
2047config ARCH_SUPPORTS_KEXEC_SIG
2048	def_bool y
2049
2050config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2051	def_bool y
2052
2053config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2054	def_bool y
2055
2056config ARCH_SUPPORTS_KEXEC_JUMP
2057	def_bool y
2058
2059config ARCH_SUPPORTS_CRASH_DUMP
2060	def_bool X86_64 || (X86_32 && HIGHMEM)
2061
2062config ARCH_SUPPORTS_CRASH_HOTPLUG
2063	def_bool y
2064
2065config PHYSICAL_START
2066	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2067	default "0x1000000"
2068	help
2069	  This gives the physical address where the kernel is loaded.
2070
2071	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2072	  bzImage will decompress itself to above physical address and
2073	  run from there. Otherwise, bzImage will run from the address where
2074	  it has been loaded by the boot loader and will ignore above physical
2075	  address.
2076
2077	  In normal kdump cases one does not have to set/change this option
2078	  as now bzImage can be compiled as a completely relocatable image
2079	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2080	  address. This option is mainly useful for the folks who don't want
2081	  to use a bzImage for capturing the crash dump and want to use a
2082	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2083	  to be specifically compiled to run from a specific memory area
2084	  (normally a reserved region) and this option comes handy.
2085
2086	  So if you are using bzImage for capturing the crash dump,
2087	  leave the value here unchanged to 0x1000000 and set
2088	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2089	  for capturing the crash dump change this value to start of
2090	  the reserved region.  In other words, it can be set based on
2091	  the "X" value as specified in the "crashkernel=YM@XM"
2092	  command line boot parameter passed to the panic-ed
2093	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2094	  for more details about crash dumps.
2095
2096	  Usage of bzImage for capturing the crash dump is recommended as
2097	  one does not have to build two kernels. Same kernel can be used
2098	  as production kernel and capture kernel. Above option should have
2099	  gone away after relocatable bzImage support is introduced. But it
2100	  is present because there are users out there who continue to use
2101	  vmlinux for dump capture. This option should go away down the
2102	  line.
2103
2104	  Don't change this unless you know what you are doing.
2105
2106config RELOCATABLE
2107	bool "Build a relocatable kernel"
2108	default y
2109	help
2110	  This builds a kernel image that retains relocation information
2111	  so it can be loaded someplace besides the default 1MB.
2112	  The relocations tend to make the kernel binary about 10% larger,
2113	  but are discarded at runtime.
2114
2115	  One use is for the kexec on panic case where the recovery kernel
2116	  must live at a different physical address than the primary
2117	  kernel.
2118
2119	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2120	  it has been loaded at and the compile time physical address
2121	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2122
2123config RANDOMIZE_BASE
2124	bool "Randomize the address of the kernel image (KASLR)"
2125	depends on RELOCATABLE
2126	default y
2127	help
2128	  In support of Kernel Address Space Layout Randomization (KASLR),
2129	  this randomizes the physical address at which the kernel image
2130	  is decompressed and the virtual address where the kernel
2131	  image is mapped, as a security feature that deters exploit
2132	  attempts relying on knowledge of the location of kernel
2133	  code internals.
2134
2135	  On 64-bit, the kernel physical and virtual addresses are
2136	  randomized separately. The physical address will be anywhere
2137	  between 16MB and the top of physical memory (up to 64TB). The
2138	  virtual address will be randomized from 16MB up to 1GB (9 bits
2139	  of entropy). Note that this also reduces the memory space
2140	  available to kernel modules from 1.5GB to 1GB.
2141
2142	  On 32-bit, the kernel physical and virtual addresses are
2143	  randomized together. They will be randomized from 16MB up to
2144	  512MB (8 bits of entropy).
2145
2146	  Entropy is generated using the RDRAND instruction if it is
2147	  supported. If RDTSC is supported, its value is mixed into
2148	  the entropy pool as well. If neither RDRAND nor RDTSC are
2149	  supported, then entropy is read from the i8254 timer. The
2150	  usable entropy is limited by the kernel being built using
2151	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2152	  minimum of 2MB. As a result, only 10 bits of entropy are
2153	  theoretically possible, but the implementations are further
2154	  limited due to memory layouts.
2155
2156	  If unsure, say Y.
2157
2158# Relocation on x86 needs some additional build support
2159config X86_NEED_RELOCS
2160	def_bool y
2161	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2162
2163config PHYSICAL_ALIGN
2164	hex "Alignment value to which kernel should be aligned"
2165	default "0x200000"
2166	range 0x2000 0x1000000 if X86_32
2167	range 0x200000 0x1000000 if X86_64
2168	help
2169	  This value puts the alignment restrictions on physical address
2170	  where kernel is loaded and run from. Kernel is compiled for an
2171	  address which meets above alignment restriction.
2172
2173	  If bootloader loads the kernel at a non-aligned address and
2174	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2175	  address aligned to above value and run from there.
2176
2177	  If bootloader loads the kernel at a non-aligned address and
2178	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2179	  load address and decompress itself to the address it has been
2180	  compiled for and run from there. The address for which kernel is
2181	  compiled already meets above alignment restrictions. Hence the
2182	  end result is that kernel runs from a physical address meeting
2183	  above alignment restrictions.
2184
2185	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2186	  this value must be a multiple of 0x200000.
2187
2188	  Don't change this unless you know what you are doing.
2189
2190config DYNAMIC_MEMORY_LAYOUT
2191	bool
2192	help
2193	  This option makes base addresses of vmalloc and vmemmap as well as
2194	  __PAGE_OFFSET movable during boot.
2195
2196config RANDOMIZE_MEMORY
2197	bool "Randomize the kernel memory sections"
2198	depends on X86_64
2199	depends on RANDOMIZE_BASE
2200	select DYNAMIC_MEMORY_LAYOUT
2201	default RANDOMIZE_BASE
2202	help
2203	  Randomizes the base virtual address of kernel memory sections
2204	  (physical memory mapping, vmalloc & vmemmap). This security feature
2205	  makes exploits relying on predictable memory locations less reliable.
2206
2207	  The order of allocations remains unchanged. Entropy is generated in
2208	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2209	  configuration have in average 30,000 different possible virtual
2210	  addresses for each memory section.
2211
2212	  If unsure, say Y.
2213
2214config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2215	hex "Physical memory mapping padding" if EXPERT
2216	depends on RANDOMIZE_MEMORY
2217	default "0xa" if MEMORY_HOTPLUG
2218	default "0x0"
2219	range 0x1 0x40 if MEMORY_HOTPLUG
2220	range 0x0 0x40
2221	help
2222	  Define the padding in terabytes added to the existing physical
2223	  memory size during kernel memory randomization. It is useful
2224	  for memory hotplug support but reduces the entropy available for
2225	  address randomization.
2226
2227	  If unsure, leave at the default value.
2228
2229config ADDRESS_MASKING
2230	bool "Linear Address Masking support"
2231	depends on X86_64
2232	help
2233	  Linear Address Masking (LAM) modifies the checking that is applied
2234	  to 64-bit linear addresses, allowing software to use of the
2235	  untranslated address bits for metadata.
2236
2237	  The capability can be used for efficient address sanitizers (ASAN)
2238	  implementation and for optimizations in JITs.
2239
2240config HOTPLUG_CPU
2241	def_bool y
2242	depends on SMP
2243
2244config COMPAT_VDSO
2245	def_bool n
2246	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2247	depends on COMPAT_32
2248	help
2249	  Certain buggy versions of glibc will crash if they are
2250	  presented with a 32-bit vDSO that is not mapped at the address
2251	  indicated in its segment table.
2252
2253	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2254	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2255	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2256	  the only released version with the bug, but OpenSUSE 9
2257	  contains a buggy "glibc 2.3.2".
2258
2259	  The symptom of the bug is that everything crashes on startup, saying:
2260	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2261
2262	  Saying Y here changes the default value of the vdso32 boot
2263	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2264	  This works around the glibc bug but hurts performance.
2265
2266	  If unsure, say N: if you are compiling your own kernel, you
2267	  are unlikely to be using a buggy version of glibc.
2268
2269choice
2270	prompt "vsyscall table for legacy applications"
2271	depends on X86_64
2272	default LEGACY_VSYSCALL_XONLY
2273	help
2274	  Legacy user code that does not know how to find the vDSO expects
2275	  to be able to issue three syscalls by calling fixed addresses in
2276	  kernel space. Since this location is not randomized with ASLR,
2277	  it can be used to assist security vulnerability exploitation.
2278
2279	  This setting can be changed at boot time via the kernel command
2280	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2281	  is deprecated and can only be enabled using the kernel command
2282	  line.
2283
2284	  On a system with recent enough glibc (2.14 or newer) and no
2285	  static binaries, you can say None without a performance penalty
2286	  to improve security.
2287
2288	  If unsure, select "Emulate execution only".
2289
2290	config LEGACY_VSYSCALL_XONLY
2291		bool "Emulate execution only"
2292		help
2293		  The kernel traps and emulates calls into the fixed vsyscall
2294		  address mapping and does not allow reads.  This
2295		  configuration is recommended when userspace might use the
2296		  legacy vsyscall area but support for legacy binary
2297		  instrumentation of legacy code is not needed.  It mitigates
2298		  certain uses of the vsyscall area as an ASLR-bypassing
2299		  buffer.
2300
2301	config LEGACY_VSYSCALL_NONE
2302		bool "None"
2303		help
2304		  There will be no vsyscall mapping at all. This will
2305		  eliminate any risk of ASLR bypass due to the vsyscall
2306		  fixed address mapping. Attempts to use the vsyscalls
2307		  will be reported to dmesg, so that either old or
2308		  malicious userspace programs can be identified.
2309
2310endchoice
2311
2312config CMDLINE_BOOL
2313	bool "Built-in kernel command line"
2314	help
2315	  Allow for specifying boot arguments to the kernel at
2316	  build time.  On some systems (e.g. embedded ones), it is
2317	  necessary or convenient to provide some or all of the
2318	  kernel boot arguments with the kernel itself (that is,
2319	  to not rely on the boot loader to provide them.)
2320
2321	  To compile command line arguments into the kernel,
2322	  set this option to 'Y', then fill in the
2323	  boot arguments in CONFIG_CMDLINE.
2324
2325	  Systems with fully functional boot loaders (i.e. non-embedded)
2326	  should leave this option set to 'N'.
2327
2328config CMDLINE
2329	string "Built-in kernel command string"
2330	depends on CMDLINE_BOOL
2331	default ""
2332	help
2333	  Enter arguments here that should be compiled into the kernel
2334	  image and used at boot time.  If the boot loader provides a
2335	  command line at boot time, it is appended to this string to
2336	  form the full kernel command line, when the system boots.
2337
2338	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2339	  change this behavior.
2340
2341	  In most cases, the command line (whether built-in or provided
2342	  by the boot loader) should specify the device for the root
2343	  file system.
2344
2345config CMDLINE_OVERRIDE
2346	bool "Built-in command line overrides boot loader arguments"
2347	depends on CMDLINE_BOOL && CMDLINE != ""
2348	help
2349	  Set this option to 'Y' to have the kernel ignore the boot loader
2350	  command line, and use ONLY the built-in command line.
2351
2352	  This is used to work around broken boot loaders.  This should
2353	  be set to 'N' under normal conditions.
2354
2355config MODIFY_LDT_SYSCALL
2356	bool "Enable the LDT (local descriptor table)" if EXPERT
2357	default y
2358	help
2359	  Linux can allow user programs to install a per-process x86
2360	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2361	  call.  This is required to run 16-bit or segmented code such as
2362	  DOSEMU or some Wine programs.  It is also used by some very old
2363	  threading libraries.
2364
2365	  Enabling this feature adds a small amount of overhead to
2366	  context switches and increases the low-level kernel attack
2367	  surface.  Disabling it removes the modify_ldt(2) system call.
2368
2369	  Saying 'N' here may make sense for embedded or server kernels.
2370
2371config STRICT_SIGALTSTACK_SIZE
2372	bool "Enforce strict size checking for sigaltstack"
2373	depends on DYNAMIC_SIGFRAME
2374	help
2375	  For historical reasons MINSIGSTKSZ is a constant which became
2376	  already too small with AVX512 support. Add a mechanism to
2377	  enforce strict checking of the sigaltstack size against the
2378	  real size of the FPU frame. This option enables the check
2379	  by default. It can also be controlled via the kernel command
2380	  line option 'strict_sas_size' independent of this config
2381	  switch. Enabling it might break existing applications which
2382	  allocate a too small sigaltstack but 'work' because they
2383	  never get a signal delivered.
2384
2385	  Say 'N' unless you want to really enforce this check.
2386
2387source "kernel/livepatch/Kconfig"
2388
2389endmenu
2390
2391config CC_HAS_SLS
2392	def_bool $(cc-option,-mharden-sls=all)
2393
2394config CC_HAS_RETURN_THUNK
2395	def_bool $(cc-option,-mfunction-return=thunk-extern)
2396
2397config CC_HAS_ENTRY_PADDING
2398	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2399
2400config FUNCTION_PADDING_CFI
2401	int
2402	default 59 if FUNCTION_ALIGNMENT_64B
2403	default 27 if FUNCTION_ALIGNMENT_32B
2404	default 11 if FUNCTION_ALIGNMENT_16B
2405	default  3 if FUNCTION_ALIGNMENT_8B
2406	default  0
2407
2408# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2409# except Kconfig can't do arithmetic :/
2410config FUNCTION_PADDING_BYTES
2411	int
2412	default FUNCTION_PADDING_CFI if CFI_CLANG
2413	default FUNCTION_ALIGNMENT
2414
2415config CALL_PADDING
2416	def_bool n
2417	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2418	select FUNCTION_ALIGNMENT_16B
2419
2420config FINEIBT
2421	def_bool y
2422	depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE
2423	select CALL_PADDING
2424
2425config HAVE_CALL_THUNKS
2426	def_bool y
2427	depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL
2428
2429config CALL_THUNKS
2430	def_bool n
2431	select CALL_PADDING
2432
2433config PREFIX_SYMBOLS
2434	def_bool y
2435	depends on CALL_PADDING && !CFI_CLANG
2436
2437menuconfig SPECULATION_MITIGATIONS
2438	bool "Mitigations for speculative execution vulnerabilities"
2439	default y
2440	help
2441	  Say Y here to enable options which enable mitigations for
2442	  speculative execution hardware vulnerabilities.
2443
2444	  If you say N, all mitigations will be disabled. You really
2445	  should know what you are doing to say so.
2446
2447if SPECULATION_MITIGATIONS
2448
2449config PAGE_TABLE_ISOLATION
2450	bool "Remove the kernel mapping in user mode"
2451	default y
2452	depends on (X86_64 || X86_PAE)
2453	help
2454	  This feature reduces the number of hardware side channels by
2455	  ensuring that the majority of kernel addresses are not mapped
2456	  into userspace.
2457
2458	  See Documentation/arch/x86/pti.rst for more details.
2459
2460config RETPOLINE
2461	bool "Avoid speculative indirect branches in kernel"
2462	select OBJTOOL if HAVE_OBJTOOL
2463	default y
2464	help
2465	  Compile kernel with the retpoline compiler options to guard against
2466	  kernel-to-user data leaks by avoiding speculative indirect
2467	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2468	  support for full protection. The kernel may run slower.
2469
2470config RETHUNK
2471	bool "Enable return-thunks"
2472	depends on RETPOLINE && CC_HAS_RETURN_THUNK
2473	select OBJTOOL if HAVE_OBJTOOL
2474	default y if X86_64
2475	help
2476	  Compile the kernel with the return-thunks compiler option to guard
2477	  against kernel-to-user data leaks by avoiding return speculation.
2478	  Requires a compiler with -mfunction-return=thunk-extern
2479	  support for full protection. The kernel may run slower.
2480
2481config CPU_UNRET_ENTRY
2482	bool "Enable UNRET on kernel entry"
2483	depends on CPU_SUP_AMD && RETHUNK && X86_64
2484	default y
2485	help
2486	  Compile the kernel with support for the retbleed=unret mitigation.
2487
2488config CALL_DEPTH_TRACKING
2489	bool "Mitigate RSB underflow with call depth tracking"
2490	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2491	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2492	select CALL_THUNKS
2493	default y
2494	help
2495	  Compile the kernel with call depth tracking to mitigate the Intel
2496	  SKL Return-Speculation-Buffer (RSB) underflow issue. The
2497	  mitigation is off by default and needs to be enabled on the
2498	  kernel command line via the retbleed=stuff option. For
2499	  non-affected systems the overhead of this option is marginal as
2500	  the call depth tracking is using run-time generated call thunks
2501	  in a compiler generated padding area and call patching. This
2502	  increases text size by ~5%. For non affected systems this space
2503	  is unused. On affected SKL systems this results in a significant
2504	  performance gain over the IBRS mitigation.
2505
2506config CALL_THUNKS_DEBUG
2507	bool "Enable call thunks and call depth tracking debugging"
2508	depends on CALL_DEPTH_TRACKING
2509	select FUNCTION_ALIGNMENT_32B
2510	default n
2511	help
2512	  Enable call/ret counters for imbalance detection and build in
2513	  a noisy dmesg about callthunks generation and call patching for
2514	  trouble shooting. The debug prints need to be enabled on the
2515	  kernel command line with 'debug-callthunks'.
2516	  Only enable this when you are debugging call thunks as this
2517	  creates a noticeable runtime overhead. If unsure say N.
2518
2519config CPU_IBPB_ENTRY
2520	bool "Enable IBPB on kernel entry"
2521	depends on CPU_SUP_AMD && X86_64
2522	default y
2523	help
2524	  Compile the kernel with support for the retbleed=ibpb mitigation.
2525
2526config CPU_IBRS_ENTRY
2527	bool "Enable IBRS on kernel entry"
2528	depends on CPU_SUP_INTEL && X86_64
2529	default y
2530	help
2531	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2532	  This mitigates both spectre_v2 and retbleed at great cost to
2533	  performance.
2534
2535config CPU_SRSO
2536	bool "Mitigate speculative RAS overflow on AMD"
2537	depends on CPU_SUP_AMD && X86_64 && RETHUNK
2538	default y
2539	help
2540	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2541
2542config SLS
2543	bool "Mitigate Straight-Line-Speculation"
2544	depends on CC_HAS_SLS && X86_64
2545	select OBJTOOL if HAVE_OBJTOOL
2546	default n
2547	help
2548	  Compile the kernel with straight-line-speculation options to guard
2549	  against straight line speculation. The kernel image might be slightly
2550	  larger.
2551
2552config GDS_FORCE_MITIGATION
2553	bool "Force GDS Mitigation"
2554	depends on CPU_SUP_INTEL
2555	default n
2556	help
2557	  Gather Data Sampling (GDS) is a hardware vulnerability which allows
2558	  unprivileged speculative access to data which was previously stored in
2559	  vector registers.
2560
2561	  This option is equivalent to setting gather_data_sampling=force on the
2562	  command line. The microcode mitigation is used if present, otherwise
2563	  AVX is disabled as a mitigation. On affected systems that are missing
2564	  the microcode any userspace code that unconditionally uses AVX will
2565	  break with this option set.
2566
2567	  Setting this option on systems not vulnerable to GDS has no effect.
2568
2569	  If in doubt, say N.
2570
2571endif
2572
2573config ARCH_HAS_ADD_PAGES
2574	def_bool y
2575	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2576
2577menu "Power management and ACPI options"
2578
2579config ARCH_HIBERNATION_HEADER
2580	def_bool y
2581	depends on HIBERNATION
2582
2583source "kernel/power/Kconfig"
2584
2585source "drivers/acpi/Kconfig"
2586
2587config X86_APM_BOOT
2588	def_bool y
2589	depends on APM
2590
2591menuconfig APM
2592	tristate "APM (Advanced Power Management) BIOS support"
2593	depends on X86_32 && PM_SLEEP
2594	help
2595	  APM is a BIOS specification for saving power using several different
2596	  techniques. This is mostly useful for battery powered laptops with
2597	  APM compliant BIOSes. If you say Y here, the system time will be
2598	  reset after a RESUME operation, the /proc/apm device will provide
2599	  battery status information, and user-space programs will receive
2600	  notification of APM "events" (e.g. battery status change).
2601
2602	  If you select "Y" here, you can disable actual use of the APM
2603	  BIOS by passing the "apm=off" option to the kernel at boot time.
2604
2605	  Note that the APM support is almost completely disabled for
2606	  machines with more than one CPU.
2607
2608	  In order to use APM, you will need supporting software. For location
2609	  and more information, read <file:Documentation/power/apm-acpi.rst>
2610	  and the Battery Powered Linux mini-HOWTO, available from
2611	  <http://www.tldp.org/docs.html#howto>.
2612
2613	  This driver does not spin down disk drives (see the hdparm(8)
2614	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2615	  VESA-compliant "green" monitors.
2616
2617	  This driver does not support the TI 4000M TravelMate and the ACER
2618	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2619	  desktop machines also don't have compliant BIOSes, and this driver
2620	  may cause those machines to panic during the boot phase.
2621
2622	  Generally, if you don't have a battery in your machine, there isn't
2623	  much point in using this driver and you should say N. If you get
2624	  random kernel OOPSes or reboots that don't seem to be related to
2625	  anything, try disabling/enabling this option (or disabling/enabling
2626	  APM in your BIOS).
2627
2628	  Some other things you should try when experiencing seemingly random,
2629	  "weird" problems:
2630
2631	  1) make sure that you have enough swap space and that it is
2632	  enabled.
2633	  2) pass the "idle=poll" option to the kernel
2634	  3) switch on floating point emulation in the kernel and pass
2635	  the "no387" option to the kernel
2636	  4) pass the "floppy=nodma" option to the kernel
2637	  5) pass the "mem=4M" option to the kernel (thereby disabling
2638	  all but the first 4 MB of RAM)
2639	  6) make sure that the CPU is not over clocked.
2640	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2641	  8) disable the cache from your BIOS settings
2642	  9) install a fan for the video card or exchange video RAM
2643	  10) install a better fan for the CPU
2644	  11) exchange RAM chips
2645	  12) exchange the motherboard.
2646
2647	  To compile this driver as a module, choose M here: the
2648	  module will be called apm.
2649
2650if APM
2651
2652config APM_IGNORE_USER_SUSPEND
2653	bool "Ignore USER SUSPEND"
2654	help
2655	  This option will ignore USER SUSPEND requests. On machines with a
2656	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2657	  series notebooks, it is necessary to say Y because of a BIOS bug.
2658
2659config APM_DO_ENABLE
2660	bool "Enable PM at boot time"
2661	help
2662	  Enable APM features at boot time. From page 36 of the APM BIOS
2663	  specification: "When disabled, the APM BIOS does not automatically
2664	  power manage devices, enter the Standby State, enter the Suspend
2665	  State, or take power saving steps in response to CPU Idle calls."
2666	  This driver will make CPU Idle calls when Linux is idle (unless this
2667	  feature is turned off -- see "Do CPU IDLE calls", below). This
2668	  should always save battery power, but more complicated APM features
2669	  will be dependent on your BIOS implementation. You may need to turn
2670	  this option off if your computer hangs at boot time when using APM
2671	  support, or if it beeps continuously instead of suspending. Turn
2672	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2673	  T400CDT. This is off by default since most machines do fine without
2674	  this feature.
2675
2676config APM_CPU_IDLE
2677	depends on CPU_IDLE
2678	bool "Make CPU Idle calls when idle"
2679	help
2680	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2681	  On some machines, this can activate improved power savings, such as
2682	  a slowed CPU clock rate, when the machine is idle. These idle calls
2683	  are made after the idle loop has run for some length of time (e.g.,
2684	  333 mS). On some machines, this will cause a hang at boot time or
2685	  whenever the CPU becomes idle. (On machines with more than one CPU,
2686	  this option does nothing.)
2687
2688config APM_DISPLAY_BLANK
2689	bool "Enable console blanking using APM"
2690	help
2691	  Enable console blanking using the APM. Some laptops can use this to
2692	  turn off the LCD backlight when the screen blanker of the Linux
2693	  virtual console blanks the screen. Note that this is only used by
2694	  the virtual console screen blanker, and won't turn off the backlight
2695	  when using the X Window system. This also doesn't have anything to
2696	  do with your VESA-compliant power-saving monitor. Further, this
2697	  option doesn't work for all laptops -- it might not turn off your
2698	  backlight at all, or it might print a lot of errors to the console,
2699	  especially if you are using gpm.
2700
2701config APM_ALLOW_INTS
2702	bool "Allow interrupts during APM BIOS calls"
2703	help
2704	  Normally we disable external interrupts while we are making calls to
2705	  the APM BIOS as a measure to lessen the effects of a badly behaving
2706	  BIOS implementation.  The BIOS should reenable interrupts if it
2707	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2708	  many of the newer IBM Thinkpads.  If you experience hangs when you
2709	  suspend, try setting this to Y.  Otherwise, say N.
2710
2711endif # APM
2712
2713source "drivers/cpufreq/Kconfig"
2714
2715source "drivers/cpuidle/Kconfig"
2716
2717source "drivers/idle/Kconfig"
2718
2719endmenu
2720
2721menu "Bus options (PCI etc.)"
2722
2723choice
2724	prompt "PCI access mode"
2725	depends on X86_32 && PCI
2726	default PCI_GOANY
2727	help
2728	  On PCI systems, the BIOS can be used to detect the PCI devices and
2729	  determine their configuration. However, some old PCI motherboards
2730	  have BIOS bugs and may crash if this is done. Also, some embedded
2731	  PCI-based systems don't have any BIOS at all. Linux can also try to
2732	  detect the PCI hardware directly without using the BIOS.
2733
2734	  With this option, you can specify how Linux should detect the
2735	  PCI devices. If you choose "BIOS", the BIOS will be used,
2736	  if you choose "Direct", the BIOS won't be used, and if you
2737	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2738	  If you choose "Any", the kernel will try MMCONFIG, then the
2739	  direct access method and falls back to the BIOS if that doesn't
2740	  work. If unsure, go with the default, which is "Any".
2741
2742config PCI_GOBIOS
2743	bool "BIOS"
2744
2745config PCI_GOMMCONFIG
2746	bool "MMConfig"
2747
2748config PCI_GODIRECT
2749	bool "Direct"
2750
2751config PCI_GOOLPC
2752	bool "OLPC XO-1"
2753	depends on OLPC
2754
2755config PCI_GOANY
2756	bool "Any"
2757
2758endchoice
2759
2760config PCI_BIOS
2761	def_bool y
2762	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2763
2764# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2765config PCI_DIRECT
2766	def_bool y
2767	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2768
2769config PCI_MMCONFIG
2770	bool "Support mmconfig PCI config space access" if X86_64
2771	default y
2772	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2773	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2774
2775config PCI_OLPC
2776	def_bool y
2777	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2778
2779config PCI_XEN
2780	def_bool y
2781	depends on PCI && XEN
2782
2783config MMCONF_FAM10H
2784	def_bool y
2785	depends on X86_64 && PCI_MMCONFIG && ACPI
2786
2787config PCI_CNB20LE_QUIRK
2788	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2789	depends on PCI
2790	help
2791	  Read the PCI windows out of the CNB20LE host bridge. This allows
2792	  PCI hotplug to work on systems with the CNB20LE chipset which do
2793	  not have ACPI.
2794
2795	  There's no public spec for this chipset, and this functionality
2796	  is known to be incomplete.
2797
2798	  You should say N unless you know you need this.
2799
2800config ISA_BUS
2801	bool "ISA bus support on modern systems" if EXPERT
2802	help
2803	  Expose ISA bus device drivers and options available for selection and
2804	  configuration. Enable this option if your target machine has an ISA
2805	  bus. ISA is an older system, displaced by PCI and newer bus
2806	  architectures -- if your target machine is modern, it probably does
2807	  not have an ISA bus.
2808
2809	  If unsure, say N.
2810
2811# x86_64 have no ISA slots, but can have ISA-style DMA.
2812config ISA_DMA_API
2813	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2814	default y
2815	help
2816	  Enables ISA-style DMA support for devices requiring such controllers.
2817	  If unsure, say Y.
2818
2819if X86_32
2820
2821config ISA
2822	bool "ISA support"
2823	help
2824	  Find out whether you have ISA slots on your motherboard.  ISA is the
2825	  name of a bus system, i.e. the way the CPU talks to the other stuff
2826	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2827	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2828	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2829
2830config SCx200
2831	tristate "NatSemi SCx200 support"
2832	help
2833	  This provides basic support for National Semiconductor's
2834	  (now AMD's) Geode processors.  The driver probes for the
2835	  PCI-IDs of several on-chip devices, so its a good dependency
2836	  for other scx200_* drivers.
2837
2838	  If compiled as a module, the driver is named scx200.
2839
2840config SCx200HR_TIMER
2841	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2842	depends on SCx200
2843	default y
2844	help
2845	  This driver provides a clocksource built upon the on-chip
2846	  27MHz high-resolution timer.  Its also a workaround for
2847	  NSC Geode SC-1100's buggy TSC, which loses time when the
2848	  processor goes idle (as is done by the scheduler).  The
2849	  other workaround is idle=poll boot option.
2850
2851config OLPC
2852	bool "One Laptop Per Child support"
2853	depends on !X86_PAE
2854	select GPIOLIB
2855	select OF
2856	select OF_PROMTREE
2857	select IRQ_DOMAIN
2858	select OLPC_EC
2859	help
2860	  Add support for detecting the unique features of the OLPC
2861	  XO hardware.
2862
2863config OLPC_XO1_PM
2864	bool "OLPC XO-1 Power Management"
2865	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2866	help
2867	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2868
2869config OLPC_XO1_RTC
2870	bool "OLPC XO-1 Real Time Clock"
2871	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2872	help
2873	  Add support for the XO-1 real time clock, which can be used as a
2874	  programmable wakeup source.
2875
2876config OLPC_XO1_SCI
2877	bool "OLPC XO-1 SCI extras"
2878	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2879	depends on INPUT=y
2880	select POWER_SUPPLY
2881	help
2882	  Add support for SCI-based features of the OLPC XO-1 laptop:
2883	   - EC-driven system wakeups
2884	   - Power button
2885	   - Ebook switch
2886	   - Lid switch
2887	   - AC adapter status updates
2888	   - Battery status updates
2889
2890config OLPC_XO15_SCI
2891	bool "OLPC XO-1.5 SCI extras"
2892	depends on OLPC && ACPI
2893	select POWER_SUPPLY
2894	help
2895	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2896	   - EC-driven system wakeups
2897	   - AC adapter status updates
2898	   - Battery status updates
2899
2900config ALIX
2901	bool "PCEngines ALIX System Support (LED setup)"
2902	select GPIOLIB
2903	help
2904	  This option enables system support for the PCEngines ALIX.
2905	  At present this just sets up LEDs for GPIO control on
2906	  ALIX2/3/6 boards.  However, other system specific setup should
2907	  get added here.
2908
2909	  Note: You must still enable the drivers for GPIO and LED support
2910	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2911
2912	  Note: You have to set alix.force=1 for boards with Award BIOS.
2913
2914config NET5501
2915	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2916	select GPIOLIB
2917	help
2918	  This option enables system support for the Soekris Engineering net5501.
2919
2920config GEOS
2921	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2922	select GPIOLIB
2923	depends on DMI
2924	help
2925	  This option enables system support for the Traverse Technologies GEOS.
2926
2927config TS5500
2928	bool "Technologic Systems TS-5500 platform support"
2929	depends on MELAN
2930	select CHECK_SIGNATURE
2931	select NEW_LEDS
2932	select LEDS_CLASS
2933	help
2934	  This option enables system support for the Technologic Systems TS-5500.
2935
2936endif # X86_32
2937
2938config AMD_NB
2939	def_bool y
2940	depends on CPU_SUP_AMD && PCI
2941
2942endmenu
2943
2944menu "Binary Emulations"
2945
2946config IA32_EMULATION
2947	bool "IA32 Emulation"
2948	depends on X86_64
2949	select ARCH_WANT_OLD_COMPAT_IPC
2950	select BINFMT_ELF
2951	select COMPAT_OLD_SIGACTION
2952	help
2953	  Include code to run legacy 32-bit programs under a
2954	  64-bit kernel. You should likely turn this on, unless you're
2955	  100% sure that you don't have any 32-bit programs left.
2956
2957config X86_X32_ABI
2958	bool "x32 ABI for 64-bit mode"
2959	depends on X86_64
2960	# llvm-objcopy does not convert x86_64 .note.gnu.property or
2961	# compressed debug sections to x86_x32 properly:
2962	# https://github.com/ClangBuiltLinux/linux/issues/514
2963	# https://github.com/ClangBuiltLinux/linux/issues/1141
2964	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
2965	help
2966	  Include code to run binaries for the x32 native 32-bit ABI
2967	  for 64-bit processors.  An x32 process gets access to the
2968	  full 64-bit register file and wide data path while leaving
2969	  pointers at 32 bits for smaller memory footprint.
2970
2971config COMPAT_32
2972	def_bool y
2973	depends on IA32_EMULATION || X86_32
2974	select HAVE_UID16
2975	select OLD_SIGSUSPEND3
2976
2977config COMPAT
2978	def_bool y
2979	depends on IA32_EMULATION || X86_X32_ABI
2980
2981config COMPAT_FOR_U64_ALIGNMENT
2982	def_bool y
2983	depends on COMPAT
2984
2985endmenu
2986
2987config HAVE_ATOMIC_IOMAP
2988	def_bool y
2989	depends on X86_32
2990
2991source "arch/x86/kvm/Kconfig"
2992
2993source "arch/x86/Kconfig.assembler"
2994