xref: /linux/arch/x86/Kconfig (revision a6d0dbba950880e269d433222ca6d516ebe8a6ae)
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_HAS_PTDUMP
30	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
31	select ARCH_SUPPORTS_PER_VMA_LOCK
32	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
33	select HAVE_ARCH_SOFT_DIRTY
34	select MODULES_USE_ELF_RELA
35	select NEED_DMA_MAP_STATE
36	select SWIOTLB
37	select ARCH_HAS_ELFCORE_COMPAT
38	select ZONE_DMA32
39	select EXECMEM if DYNAMIC_FTRACE
40
41config FORCE_DYNAMIC_FTRACE
42	def_bool y
43	depends on X86_32
44	depends on FUNCTION_TRACER
45	select DYNAMIC_FTRACE
46	help
47	  We keep the static function tracing (!DYNAMIC_FTRACE) around
48	  in order to test the non static function tracing in the
49	  generic code, as other architectures still use it. But we
50	  only need to keep it around for x86_64. No need to keep it
51	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
52#
53# Arch settings
54#
55# ( Note that options that are marked 'if X86_64' could in principle be
56#   ported to 32-bit as well. )
57#
58config X86
59	def_bool y
60	#
61	# Note: keep this list sorted alphabetically
62	#
63	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
64	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
65	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
66	select ARCH_32BIT_OFF_T			if X86_32
67	select ARCH_CLOCKSOURCE_INIT
68	select ARCH_CONFIGURES_CPU_MITIGATIONS
69	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
70	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
71	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
72	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
73	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
74	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
75	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
76	select ARCH_HAS_CACHE_LINE_SIZE
77	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
78	select ARCH_HAS_CPU_FINALIZE_INIT
79	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
80	select ARCH_HAS_CRC32
81	select ARCH_HAS_CRC64			if X86_64
82	select ARCH_HAS_CRC_T10DIF
83	select ARCH_HAS_CURRENT_STACK_POINTER
84	select ARCH_HAS_DEBUG_VIRTUAL
85	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
86	select ARCH_HAS_DEVMEM_IS_ALLOWED
87	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
88	select ARCH_HAS_EARLY_DEBUG		if KGDB
89	select ARCH_HAS_ELF_RANDOMIZE
90	select ARCH_HAS_EXECMEM_ROX		if X86_64
91	select ARCH_HAS_FAST_MULTIPLIER
92	select ARCH_HAS_FORTIFY_SOURCE
93	select ARCH_HAS_GCOV_PROFILE_ALL
94	select ARCH_HAS_KCOV			if X86_64
95	select ARCH_HAS_KERNEL_FPU_SUPPORT
96	select ARCH_HAS_MEM_ENCRYPT
97	select ARCH_HAS_MEMBARRIER_SYNC_CORE
98	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
99	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
100	select ARCH_HAS_PMEM_API		if X86_64
101	select ARCH_HAS_PREEMPT_LAZY
102	select ARCH_HAS_PTE_DEVMAP		if X86_64
103	select ARCH_HAS_PTE_SPECIAL
104	select ARCH_HAS_HW_PTE_YOUNG
105	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
106	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
107	select ARCH_HAS_COPY_MC			if X86_64
108	select ARCH_HAS_SET_MEMORY
109	select ARCH_HAS_SET_DIRECT_MAP
110	select ARCH_HAS_STRICT_KERNEL_RWX
111	select ARCH_HAS_STRICT_MODULE_RWX
112	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
113	select ARCH_HAS_SYSCALL_WRAPPER
114	select ARCH_HAS_UBSAN
115	select ARCH_HAS_DEBUG_WX
116	select ARCH_HAS_ZONE_DMA_SET if EXPERT
117	select ARCH_HAVE_NMI_SAFE_CMPXCHG
118	select ARCH_HAVE_EXTRA_ELF_NOTES
119	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
120	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
121	select ARCH_MIGHT_HAVE_PC_PARPORT
122	select ARCH_MIGHT_HAVE_PC_SERIO
123	select ARCH_STACKWALK
124	select ARCH_SUPPORTS_ACPI
125	select ARCH_SUPPORTS_ATOMIC_RMW
126	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
127	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
128	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
129	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
130	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
131	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
132	select ARCH_SUPPORTS_LTO_CLANG
133	select ARCH_SUPPORTS_LTO_CLANG_THIN
134	select ARCH_SUPPORTS_RT
135	select ARCH_SUPPORTS_AUTOFDO_CLANG
136	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
137	select ARCH_USE_BUILTIN_BSWAP
138	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CX8
139	select ARCH_USE_MEMTEST
140	select ARCH_USE_QUEUED_RWLOCKS
141	select ARCH_USE_QUEUED_SPINLOCKS
142	select ARCH_USE_SYM_ANNOTATIONS
143	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
144	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
145	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
146	select ARCH_WANTS_NO_INSTR
147	select ARCH_WANT_GENERAL_HUGETLB
148	select ARCH_WANT_HUGE_PMD_SHARE
149	select ARCH_WANT_LD_ORPHAN_WARN
150	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
151	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
152	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
153	select ARCH_WANTS_THP_SWAP		if X86_64
154	select ARCH_HAS_PARANOID_L1D_FLUSH
155	select BUILDTIME_TABLE_SORT
156	select CLKEVT_I8253
157	select CLOCKSOURCE_WATCHDOG
158	# Word-size accesses may read uninitialized data past the trailing \0
159	# in strings and cause false KMSAN reports.
160	select DCACHE_WORD_ACCESS		if !KMSAN
161	select DYNAMIC_SIGFRAME
162	select EDAC_ATOMIC_SCRUB
163	select EDAC_SUPPORT
164	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
165	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
166	select GENERIC_CLOCKEVENTS_MIN_ADJUST
167	select GENERIC_CMOS_UPDATE
168	select GENERIC_CPU_AUTOPROBE
169	select GENERIC_CPU_DEVICES
170	select GENERIC_CPU_VULNERABILITIES
171	select GENERIC_EARLY_IOREMAP
172	select GENERIC_ENTRY
173	select GENERIC_IOMAP
174	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
175	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
176	select GENERIC_IRQ_MIGRATION		if SMP
177	select GENERIC_IRQ_PROBE
178	select GENERIC_IRQ_RESERVATION_MODE
179	select GENERIC_IRQ_SHOW
180	select GENERIC_PENDING_IRQ		if SMP
181	select GENERIC_SMP_IDLE_THREAD
182	select GENERIC_TIME_VSYSCALL
183	select GENERIC_GETTIMEOFDAY
184	select GENERIC_VDSO_DATA_STORE
185	select GENERIC_VDSO_TIME_NS
186	select GENERIC_VDSO_OVERFLOW_PROTECT
187	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
188	select HARDIRQS_SW_RESEND
189	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
190	select HAS_IOPORT
191	select HAVE_ACPI_APEI			if ACPI
192	select HAVE_ACPI_APEI_NMI		if ACPI
193	select HAVE_ALIGNED_STRUCT_PAGE
194	select HAVE_ARCH_AUDITSYSCALL
195	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
196	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
197	select HAVE_ARCH_JUMP_LABEL
198	select HAVE_ARCH_JUMP_LABEL_RELATIVE
199	select HAVE_ARCH_KASAN			if X86_64
200	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
201	select HAVE_ARCH_KFENCE
202	select HAVE_ARCH_KMSAN			if X86_64
203	select HAVE_ARCH_KGDB
204	select HAVE_ARCH_MMAP_RND_BITS		if MMU
205	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
206	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
207	select HAVE_ARCH_PREL32_RELOCATIONS
208	select HAVE_ARCH_SECCOMP_FILTER
209	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
210	select HAVE_ARCH_STACKLEAK
211	select HAVE_ARCH_TRACEHOOK
212	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
213	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
214	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
215	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
216	select HAVE_ARCH_VMAP_STACK		if X86_64
217	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
218	select HAVE_ARCH_WITHIN_STACK_FRAMES
219	select HAVE_ASM_MODVERSIONS
220	select HAVE_CMPXCHG_DOUBLE
221	select HAVE_CMPXCHG_LOCAL
222	select HAVE_CONTEXT_TRACKING_USER		if X86_64
223	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
224	select HAVE_C_RECORDMCOUNT
225	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
226	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
227	select HAVE_BUILDTIME_MCOUNT_SORT
228	select HAVE_DEBUG_KMEMLEAK
229	select HAVE_DMA_CONTIGUOUS
230	select HAVE_DYNAMIC_FTRACE
231	select HAVE_DYNAMIC_FTRACE_WITH_REGS
232	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
233	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
234	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
235	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
236	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
237	select HAVE_EBPF_JIT
238	select HAVE_EFFICIENT_UNALIGNED_ACCESS
239	select HAVE_EISA			if X86_32
240	select HAVE_EXIT_THREAD
241	select HAVE_GUP_FAST
242	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
243	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
244	select HAVE_FTRACE_MCOUNT_RECORD
245	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
246	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
247	select HAVE_FUNCTION_TRACER
248	select HAVE_GCC_PLUGINS
249	select HAVE_HW_BREAKPOINT
250	select HAVE_IOREMAP_PROT
251	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
252	select HAVE_IRQ_TIME_ACCOUNTING
253	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
254	select HAVE_KERNEL_BZIP2
255	select HAVE_KERNEL_GZIP
256	select HAVE_KERNEL_LZ4
257	select HAVE_KERNEL_LZMA
258	select HAVE_KERNEL_LZO
259	select HAVE_KERNEL_XZ
260	select HAVE_KERNEL_ZSTD
261	select HAVE_KPROBES
262	select HAVE_KPROBES_ON_FTRACE
263	select HAVE_FUNCTION_ERROR_INJECTION
264	select HAVE_KRETPROBES
265	select HAVE_RETHOOK
266	select HAVE_LIVEPATCH			if X86_64
267	select HAVE_MIXED_BREAKPOINTS_REGS
268	select HAVE_MOD_ARCH_SPECIFIC
269	select HAVE_MOVE_PMD
270	select HAVE_MOVE_PUD
271	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
272	select HAVE_NMI
273	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
274	select HAVE_OBJTOOL			if X86_64
275	select HAVE_OPTPROBES
276	select HAVE_PAGE_SIZE_4KB
277	select HAVE_PCSPKR_PLATFORM
278	select HAVE_PERF_EVENTS
279	select HAVE_PERF_EVENTS_NMI
280	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
281	select HAVE_PCI
282	select HAVE_PERF_REGS
283	select HAVE_PERF_USER_STACK_DUMP
284	select MMU_GATHER_RCU_TABLE_FREE
285	select MMU_GATHER_MERGE_VMAS
286	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
287	select HAVE_REGS_AND_STACK_ACCESS_API
288	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
289	select HAVE_FUNCTION_ARG_ACCESS_API
290	select HAVE_SETUP_PER_CPU_AREA
291	select HAVE_SOFTIRQ_ON_OWN_STACK
292	select HAVE_STACKPROTECTOR
293	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
294	select HAVE_STATIC_CALL
295	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
296	select HAVE_PREEMPT_DYNAMIC_CALL
297	select HAVE_RSEQ
298	select HAVE_RUST			if X86_64
299	select HAVE_SYSCALL_TRACEPOINTS
300	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
301	select HAVE_UNSTABLE_SCHED_CLOCK
302	select HAVE_USER_RETURN_NOTIFIER
303	select HAVE_GENERIC_VDSO
304	select VDSO_GETRANDOM			if X86_64
305	select HOTPLUG_PARALLEL			if SMP && X86_64
306	select HOTPLUG_SMT			if SMP
307	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
308	select IRQ_FORCED_THREADING
309	select LOCK_MM_AND_FIND_VMA
310	select NEED_PER_CPU_EMBED_FIRST_CHUNK
311	select NEED_PER_CPU_PAGE_FIRST_CHUNK
312	select NEED_SG_DMA_LENGTH
313	select NUMA_MEMBLKS			if NUMA
314	select PCI_DOMAINS			if PCI
315	select PCI_LOCKLESS_CONFIG		if PCI
316	select PERF_EVENTS
317	select RTC_LIB
318	select RTC_MC146818_LIB
319	select SPARSE_IRQ
320	select SYSCTL_EXCEPTION_TRACE
321	select THREAD_INFO_IN_TASK
322	select TRACE_IRQFLAGS_SUPPORT
323	select TRACE_IRQFLAGS_NMI_SUPPORT
324	select USER_STACKTRACE_SUPPORT
325	select HAVE_ARCH_KCSAN			if X86_64
326	select PROC_PID_ARCH_STATUS		if PROC_FS
327	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
328	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
329	select FUNCTION_ALIGNMENT_4B
330	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
331	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
332	select ARCH_SUPPORTS_PT_RECLAIM		if X86_64
333
334config INSTRUCTION_DECODER
335	def_bool y
336	depends on KPROBES || PERF_EVENTS || UPROBES
337
338config OUTPUT_FORMAT
339	string
340	default "elf32-i386" if X86_32
341	default "elf64-x86-64" if X86_64
342
343config LOCKDEP_SUPPORT
344	def_bool y
345
346config STACKTRACE_SUPPORT
347	def_bool y
348
349config MMU
350	def_bool y
351
352config ARCH_MMAP_RND_BITS_MIN
353	default 28 if 64BIT
354	default 8
355
356config ARCH_MMAP_RND_BITS_MAX
357	default 32 if 64BIT
358	default 16
359
360config ARCH_MMAP_RND_COMPAT_BITS_MIN
361	default 8
362
363config ARCH_MMAP_RND_COMPAT_BITS_MAX
364	default 16
365
366config SBUS
367	bool
368
369config GENERIC_ISA_DMA
370	def_bool y
371	depends on ISA_DMA_API
372
373config GENERIC_CSUM
374	bool
375	default y if KMSAN || KASAN
376
377config GENERIC_BUG
378	def_bool y
379	depends on BUG
380	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
381
382config GENERIC_BUG_RELATIVE_POINTERS
383	bool
384
385config ARCH_MAY_HAVE_PC_FDC
386	def_bool y
387	depends on ISA_DMA_API
388
389config GENERIC_CALIBRATE_DELAY
390	def_bool y
391
392config ARCH_HAS_CPU_RELAX
393	def_bool y
394
395config ARCH_HIBERNATION_POSSIBLE
396	def_bool y
397
398config ARCH_SUSPEND_POSSIBLE
399	def_bool y
400
401config AUDIT_ARCH
402	def_bool y if X86_64
403
404config KASAN_SHADOW_OFFSET
405	hex
406	depends on KASAN
407	default 0xdffffc0000000000
408
409config HAVE_INTEL_TXT
410	def_bool y
411	depends on INTEL_IOMMU && ACPI
412
413config X86_64_SMP
414	def_bool y
415	depends on X86_64 && SMP
416
417config ARCH_SUPPORTS_UPROBES
418	def_bool y
419
420config FIX_EARLYCON_MEM
421	def_bool y
422
423config DYNAMIC_PHYSICAL_MASK
424	bool
425
426config PGTABLE_LEVELS
427	int
428	default 5 if X86_5LEVEL
429	default 4 if X86_64
430	default 3 if X86_PAE
431	default 2
432
433menu "Processor type and features"
434
435config SMP
436	bool "Symmetric multi-processing support"
437	help
438	  This enables support for systems with more than one CPU. If you have
439	  a system with only one CPU, say N. If you have a system with more
440	  than one CPU, say Y.
441
442	  If you say N here, the kernel will run on uni- and multiprocessor
443	  machines, but will use only one CPU of a multiprocessor machine. If
444	  you say Y here, the kernel will run on many, but not all,
445	  uniprocessor machines. On a uniprocessor machine, the kernel
446	  will run faster if you say N here.
447
448	  Note that if you say Y here and choose architecture "586" or
449	  "Pentium" under "Processor family", the kernel will not work on 486
450	  architectures. Similarly, multiprocessor kernels for the "PPro"
451	  architecture may not work on all Pentium based boards.
452
453	  People using multiprocessor machines who say Y here should also say
454	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
455	  Management" code will be disabled if you say Y here.
456
457	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
458	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
459	  <http://www.tldp.org/docs.html#howto>.
460
461	  If you don't know what to do here, say N.
462
463config X86_X2APIC
464	bool "x2APIC interrupt controller architecture support"
465	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
466	default y
467	help
468	  x2APIC is an interrupt controller architecture, a component of which
469	  (the local APIC) is present in the CPU. It allows faster access to
470	  the local APIC and supports a larger number of CPUs in the system
471	  than the predecessors.
472
473	  x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs
474	  in 2019, but it can be disabled by the BIOS. It is also frequently
475	  emulated in virtual machines, even when the host CPU does not support
476	  it. Support in the CPU can be checked by executing
477		grep x2apic /proc/cpuinfo
478
479	  If this configuration option is disabled, the kernel will boot with
480	  very reduced functionality and performance on some platforms that
481	  have x2APIC enabled. On the other hand, on hardware that does not
482	  support x2APIC, a kernel with this option enabled will just fallback
483	  to older APIC implementations.
484
485	  If in doubt, say Y.
486
487config X86_POSTED_MSI
488	bool "Enable MSI and MSI-x delivery by posted interrupts"
489	depends on X86_64 && IRQ_REMAP
490	help
491	  This enables MSIs that are under interrupt remapping to be delivered as
492	  posted interrupts to the host kernel. Interrupt throughput can
493	  potentially be improved by coalescing CPU notifications during high
494	  frequency bursts.
495
496	  If you don't know what to do here, say N.
497
498config X86_MPPARSE
499	bool "Enable MPS table" if ACPI
500	default y
501	depends on X86_LOCAL_APIC
502	help
503	  For old smp systems that do not have proper acpi support. Newer systems
504	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
505
506config X86_CPU_RESCTRL
507	bool "x86 CPU resource control support"
508	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
509	select KERNFS
510	select PROC_CPU_RESCTRL		if PROC_FS
511	select RESCTRL_FS_PSEUDO_LOCK
512	help
513	  Enable x86 CPU resource control support.
514
515	  Provide support for the allocation and monitoring of system resources
516	  usage by the CPU.
517
518	  Intel calls this Intel Resource Director Technology
519	  (Intel(R) RDT). More information about RDT can be found in the
520	  Intel x86 Architecture Software Developer Manual.
521
522	  AMD calls this AMD Platform Quality of Service (AMD QoS).
523	  More information about AMD QoS can be found in the AMD64 Technology
524	  Platform Quality of Service Extensions manual.
525
526	  Say N if unsure.
527
528config RESCTRL_FS_PSEUDO_LOCK
529	bool
530	help
531	  Software mechanism to pin data in a cache portion using
532	  micro-architecture specific knowledge.
533
534config X86_FRED
535	bool "Flexible Return and Event Delivery"
536	depends on X86_64
537	help
538	  When enabled, try to use Flexible Return and Event Delivery
539	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
540	  ring transitions and exception/interrupt handling if the
541	  system supports it.
542
543config X86_EXTENDED_PLATFORM
544	bool "Support for extended (non-PC) x86 platforms"
545	default y
546	help
547	  If you disable this option then the kernel will only support
548	  standard PC platforms. (which covers the vast majority of
549	  systems out there.)
550
551	  If you enable this option then you'll be able to select support
552	  for the following non-PC x86 platforms, depending on the value of
553	  CONFIG_64BIT.
554
555	  32-bit platforms (CONFIG_64BIT=n):
556		Goldfish (mostly Android emulator)
557		Intel CE media processor (CE4100) SoC
558		Intel Quark
559		RDC R-321x SoC
560
561	  64-bit platforms (CONFIG_64BIT=y):
562		Numascale NumaChip
563		ScaleMP vSMP
564		SGI Ultraviolet
565		Merrifield/Moorefield MID devices
566		Goldfish (mostly Android emulator)
567
568	  If you have one of these systems, or if you want to build a
569	  generic distribution kernel, say Y here - otherwise say N.
570
571# This is an alphabetically sorted list of 64 bit extended platforms
572# Please maintain the alphabetic order if and when there are additions
573config X86_NUMACHIP
574	bool "Numascale NumaChip"
575	depends on X86_64
576	depends on X86_EXTENDED_PLATFORM
577	depends on NUMA
578	depends on SMP
579	depends on X86_X2APIC
580	depends on PCI_MMCONFIG
581	help
582	  Adds support for Numascale NumaChip large-SMP systems. Needed to
583	  enable more than ~168 cores.
584	  If you don't have one of these, you should say N here.
585
586config X86_VSMP
587	bool "ScaleMP vSMP"
588	select HYPERVISOR_GUEST
589	select PARAVIRT
590	depends on X86_64 && PCI
591	depends on X86_EXTENDED_PLATFORM
592	depends on SMP
593	help
594	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
595	  supposed to run on these EM64T-based machines.  Only choose this option
596	  if you have one of these machines.
597
598config X86_UV
599	bool "SGI Ultraviolet"
600	depends on X86_64
601	depends on X86_EXTENDED_PLATFORM
602	depends on NUMA
603	depends on EFI
604	depends on KEXEC_CORE
605	depends on X86_X2APIC
606	depends on PCI
607	help
608	  This option is needed in order to support SGI Ultraviolet systems.
609	  If you don't have one of these, you should say N here.
610
611config X86_INTEL_MID
612	bool "Intel Z34xx/Z35xx MID platform support"
613	depends on X86_EXTENDED_PLATFORM
614	depends on X86_PLATFORM_DEVICES
615	depends on PCI
616	depends on X86_64 || (EXPERT && PCI_GOANY)
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 64-bit Intel MID
623	  (Mobile Internet Device) platform systems which do not have
624	  the PCI legacy interfaces.
625
626	  The only supported devices are the 22nm Merrified (Z34xx)
627	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
628	  a small number of Android devices such as the Asus Zenfone 2,
629	  Asus FonePad 8 and Dell Venue 7.
630
631	  If you are building for a PC class system or non-MID tablet
632	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
633
634	  Intel MID platforms are based on an Intel processor and chipset which
635	  consume less power than most of the x86 derivatives.
636
637config X86_GOLDFISH
638	bool "Goldfish (Virtual Platform)"
639	depends on X86_EXTENDED_PLATFORM
640	help
641	  Enable support for the Goldfish virtual platform used primarily
642	  for Android development. Unless you are building for the Android
643	  Goldfish emulator say N here.
644
645# Following is an alphabetically sorted list of 32 bit extended platforms
646# Please maintain the alphabetic order if and when there are additions
647
648config X86_INTEL_CE
649	bool "CE4100 TV platform"
650	depends on PCI
651	depends on PCI_GODIRECT
652	depends on X86_IO_APIC
653	depends on X86_32
654	depends on X86_EXTENDED_PLATFORM
655	select X86_REBOOTFIXUPS
656	select OF
657	select OF_EARLY_FLATTREE
658	help
659	  Select for the Intel CE media processor (CE4100) SOC.
660	  This option compiles in support for the CE4100 SOC for settop
661	  boxes and media devices.
662
663config X86_INTEL_QUARK
664	bool "Intel Quark platform support"
665	depends on X86_32
666	depends on X86_EXTENDED_PLATFORM
667	depends on X86_PLATFORM_DEVICES
668	depends on X86_TSC
669	depends on PCI
670	depends on PCI_GOANY
671	depends on X86_IO_APIC
672	select IOSF_MBI
673	select INTEL_IMR
674	select COMMON_CLK
675	help
676	  Select to include support for Quark X1000 SoC.
677	  Say Y here if you have a Quark based system such as the Arduino
678	  compatible Intel Galileo.
679
680config X86_RDC321X
681	bool "RDC R-321x SoC"
682	depends on X86_32
683	depends on X86_EXTENDED_PLATFORM
684	select M486
685	select X86_REBOOTFIXUPS
686	help
687	  This option is needed for RDC R-321x system-on-chip, also known
688	  as R-8610-(G).
689	  If you don't have one of these chips, you should say N here.
690
691config X86_INTEL_LPSS
692	bool "Intel Low Power Subsystem Support"
693	depends on X86 && ACPI && PCI
694	select COMMON_CLK
695	select PINCTRL
696	select IOSF_MBI
697	help
698	  Select to build support for Intel Low Power Subsystem such as
699	  found on Intel Lynxpoint PCH. Selecting this option enables
700	  things like clock tree (common clock framework) and pincontrol
701	  which are needed by the LPSS peripheral drivers.
702
703config X86_AMD_PLATFORM_DEVICE
704	bool "AMD ACPI2Platform devices support"
705	depends on ACPI
706	select COMMON_CLK
707	select PINCTRL
708	help
709	  Select to interpret AMD specific ACPI device to platform device
710	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
711	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
712	  implemented under PINCTRL subsystem.
713
714config IOSF_MBI
715	tristate "Intel SoC IOSF Sideband support for SoC platforms"
716	depends on PCI
717	help
718	  This option enables sideband register access support for Intel SoC
719	  platforms. On these platforms the IOSF sideband is used in lieu of
720	  MSR's for some register accesses, mostly but not limited to thermal
721	  and power. Drivers may query the availability of this device to
722	  determine if they need the sideband in order to work on these
723	  platforms. The sideband is available on the following SoC products.
724	  This list is not meant to be exclusive.
725	   - BayTrail
726	   - Braswell
727	   - Quark
728
729	  You should say Y if you are running a kernel on one of these SoC's.
730
731config IOSF_MBI_DEBUG
732	bool "Enable IOSF sideband access through debugfs"
733	depends on IOSF_MBI && DEBUG_FS
734	help
735	  Select this option to expose the IOSF sideband access registers (MCR,
736	  MDR, MCRX) through debugfs to write and read register information from
737	  different units on the SoC. This is most useful for obtaining device
738	  state information for debug and analysis. As this is a general access
739	  mechanism, users of this option would have specific knowledge of the
740	  device they want to access.
741
742	  If you don't require the option or are in doubt, say N.
743
744config X86_SUPPORTS_MEMORY_FAILURE
745	def_bool y
746	# MCE code calls memory_failure():
747	depends on X86_MCE
748	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
749	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
750	depends on X86_64 || !SPARSEMEM
751	select ARCH_SUPPORTS_MEMORY_FAILURE
752
753config X86_32_IRIS
754	tristate "Eurobraille/Iris poweroff module"
755	depends on X86_32
756	help
757	  The Iris machines from EuroBraille do not have APM or ACPI support
758	  to shut themselves down properly.  A special I/O sequence is
759	  needed to do so, which is what this module does at
760	  kernel shutdown.
761
762	  This is only for Iris machines from EuroBraille.
763
764	  If unused, say N.
765
766config SCHED_OMIT_FRAME_POINTER
767	def_bool y
768	prompt "Single-depth WCHAN output"
769	depends on X86
770	help
771	  Calculate simpler /proc/<PID>/wchan values. If this option
772	  is disabled then wchan values will recurse back to the
773	  caller function. This provides more accurate wchan values,
774	  at the expense of slightly more scheduling overhead.
775
776	  If in doubt, say "Y".
777
778menuconfig HYPERVISOR_GUEST
779	bool "Linux guest support"
780	help
781	  Say Y here to enable options for running Linux under various hyper-
782	  visors. This option enables basic hypervisor detection and platform
783	  setup.
784
785	  If you say N, all options in this submenu will be skipped and
786	  disabled, and Linux guest support won't be built in.
787
788if HYPERVISOR_GUEST
789
790config PARAVIRT
791	bool "Enable paravirtualization code"
792	depends on HAVE_STATIC_CALL
793	help
794	  This changes the kernel so it can modify itself when it is run
795	  under a hypervisor, potentially improving performance significantly
796	  over full virtualization.  However, when run without a hypervisor
797	  the kernel is theoretically slower and slightly larger.
798
799config PARAVIRT_XXL
800	bool
801
802config PARAVIRT_DEBUG
803	bool "paravirt-ops debugging"
804	depends on PARAVIRT && DEBUG_KERNEL
805	help
806	  Enable to debug paravirt_ops internals.  Specifically, BUG if
807	  a paravirt_op is missing when it is called.
808
809config PARAVIRT_SPINLOCKS
810	bool "Paravirtualization layer for spinlocks"
811	depends on PARAVIRT && SMP
812	help
813	  Paravirtualized spinlocks allow a pvops backend to replace the
814	  spinlock implementation with something virtualization-friendly
815	  (for example, block the virtual CPU rather than spinning).
816
817	  It has a minimal impact on native kernels and gives a nice performance
818	  benefit on paravirtualized KVM / Xen kernels.
819
820	  If you are unsure how to answer this question, answer Y.
821
822config X86_HV_CALLBACK_VECTOR
823	def_bool n
824
825source "arch/x86/xen/Kconfig"
826
827config KVM_GUEST
828	bool "KVM Guest support (including kvmclock)"
829	depends on PARAVIRT
830	select PARAVIRT_CLOCK
831	select ARCH_CPUIDLE_HALTPOLL
832	select X86_HV_CALLBACK_VECTOR
833	default y
834	help
835	  This option enables various optimizations for running under the KVM
836	  hypervisor. It includes a paravirtualized clock, so that instead
837	  of relying on a PIT (or probably other) emulation by the
838	  underlying device model, the host provides the guest with
839	  timing infrastructure such as time of day, and system time
840
841config ARCH_CPUIDLE_HALTPOLL
842	def_bool n
843	prompt "Disable host haltpoll when loading haltpoll driver"
844	help
845	  If virtualized under KVM, disable host haltpoll.
846
847config PVH
848	bool "Support for running PVH guests"
849	help
850	  This option enables the PVH entry point for guest virtual machines
851	  as specified in the x86/HVM direct boot ABI.
852
853config PARAVIRT_TIME_ACCOUNTING
854	bool "Paravirtual steal time accounting"
855	depends on PARAVIRT
856	help
857	  Select this option to enable fine granularity task steal time
858	  accounting. Time spent executing other tasks in parallel with
859	  the current vCPU is discounted from the vCPU power. To account for
860	  that, there can be a small performance impact.
861
862	  If in doubt, say N here.
863
864config PARAVIRT_CLOCK
865	bool
866
867config JAILHOUSE_GUEST
868	bool "Jailhouse non-root cell support"
869	depends on X86_64 && PCI
870	select X86_PM_TIMER
871	help
872	  This option allows to run Linux as guest in a Jailhouse non-root
873	  cell. You can leave this option disabled if you only want to start
874	  Jailhouse and run Linux afterwards in the root cell.
875
876config ACRN_GUEST
877	bool "ACRN Guest support"
878	depends on X86_64
879	select X86_HV_CALLBACK_VECTOR
880	help
881	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
882	  a flexible, lightweight reference open-source hypervisor, built with
883	  real-time and safety-criticality in mind. It is built for embedded
884	  IOT with small footprint and real-time features. More details can be
885	  found in https://projectacrn.org/.
886
887config INTEL_TDX_GUEST
888	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
889	depends on X86_64 && CPU_SUP_INTEL
890	depends on X86_X2APIC
891	depends on EFI_STUB
892	select ARCH_HAS_CC_PLATFORM
893	select X86_MEM_ENCRYPT
894	select X86_MCE
895	select UNACCEPTED_MEMORY
896	help
897	  Support running as a guest under Intel TDX.  Without this support,
898	  the guest kernel can not boot or run under TDX.
899	  TDX includes memory encryption and integrity capabilities
900	  which protect the confidentiality and integrity of guest
901	  memory contents and CPU state. TDX guests are protected from
902	  some attacks from the VMM.
903
904endif # HYPERVISOR_GUEST
905
906source "arch/x86/Kconfig.cpu"
907
908config HPET_TIMER
909	def_bool X86_64
910	prompt "HPET Timer Support" if X86_32
911	help
912	  Use the IA-PC HPET (High Precision Event Timer) to manage
913	  time in preference to the PIT and RTC, if a HPET is
914	  present.
915	  HPET is the next generation timer replacing legacy 8254s.
916	  The HPET provides a stable time base on SMP
917	  systems, unlike the TSC, but it is more expensive to access,
918	  as it is off-chip.  The interface used is documented
919	  in the HPET spec, revision 1.
920
921	  You can safely choose Y here.  However, HPET will only be
922	  activated if the platform and the BIOS support this feature.
923	  Otherwise the 8254 will be used for timing services.
924
925	  Choose N to continue using the legacy 8254 timer.
926
927config HPET_EMULATE_RTC
928	def_bool y
929	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
930
931# Mark as expert because too many people got it wrong.
932# The code disables itself when not needed.
933config DMI
934	default y
935	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
936	bool "Enable DMI scanning" if EXPERT
937	help
938	  Enabled scanning of DMI to identify machine quirks. Say Y
939	  here unless you have verified that your setup is not
940	  affected by entries in the DMI blacklist. Required by PNP
941	  BIOS code.
942
943config GART_IOMMU
944	bool "Old AMD GART IOMMU support"
945	select IOMMU_HELPER
946	select SWIOTLB
947	depends on X86_64 && PCI && AMD_NB
948	help
949	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
950	  GART based hardware IOMMUs.
951
952	  The GART supports full DMA access for devices with 32-bit access
953	  limitations, on systems with more than 3 GB. This is usually needed
954	  for USB, sound, many IDE/SATA chipsets and some other devices.
955
956	  Newer systems typically have a modern AMD IOMMU, supported via
957	  the CONFIG_AMD_IOMMU=y config option.
958
959	  In normal configurations this driver is only active when needed:
960	  there's more than 3 GB of memory and the system contains a
961	  32-bit limited device.
962
963	  If unsure, say Y.
964
965config BOOT_VESA_SUPPORT
966	bool
967	help
968	  If true, at least one selected framebuffer driver can take advantage
969	  of VESA video modes set at an early boot stage via the vga= parameter.
970
971config MAXSMP
972	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
973	depends on X86_64 && SMP && DEBUG_KERNEL
974	select CPUMASK_OFFSTACK
975	help
976	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
977	  If unsure, say N.
978
979#
980# The maximum number of CPUs supported:
981#
982# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
983# and which can be configured interactively in the
984# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
985#
986# The ranges are different on 32-bit and 64-bit kernels, depending on
987# hardware capabilities and scalability features of the kernel.
988#
989# ( If MAXSMP is enabled we just use the highest possible value and disable
990#   interactive configuration. )
991#
992
993config NR_CPUS_RANGE_BEGIN
994	int
995	default NR_CPUS_RANGE_END if MAXSMP
996	default    1 if !SMP
997	default    2
998
999config NR_CPUS_RANGE_END
1000	int
1001	depends on X86_32
1002	default    8 if  SMP
1003	default    1 if !SMP
1004
1005config NR_CPUS_RANGE_END
1006	int
1007	depends on X86_64
1008	default 8192 if  SMP && CPUMASK_OFFSTACK
1009	default  512 if  SMP && !CPUMASK_OFFSTACK
1010	default    1 if !SMP
1011
1012config NR_CPUS_DEFAULT
1013	int
1014	depends on X86_32
1015	default    8 if  SMP
1016	default    1 if !SMP
1017
1018config NR_CPUS_DEFAULT
1019	int
1020	depends on X86_64
1021	default 8192 if  MAXSMP
1022	default   64 if  SMP
1023	default    1 if !SMP
1024
1025config NR_CPUS
1026	int "Maximum number of CPUs" if SMP && !MAXSMP
1027	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1028	default NR_CPUS_DEFAULT
1029	help
1030	  This allows you to specify the maximum number of CPUs which this
1031	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1032	  supported value is 8192, otherwise the maximum value is 512.  The
1033	  minimum value which makes sense is 2.
1034
1035	  This is purely to save memory: each supported CPU adds about 8KB
1036	  to the kernel image.
1037
1038config SCHED_CLUSTER
1039	bool "Cluster scheduler support"
1040	depends on SMP
1041	default y
1042	help
1043	  Cluster scheduler support improves the CPU scheduler's decision
1044	  making when dealing with machines that have clusters of CPUs.
1045	  Cluster usually means a couple of CPUs which are placed closely
1046	  by sharing mid-level caches, last-level cache tags or internal
1047	  busses.
1048
1049config SCHED_SMT
1050	def_bool y if SMP
1051
1052config SCHED_MC
1053	def_bool y
1054	prompt "Multi-core scheduler support"
1055	depends on SMP
1056	help
1057	  Multi-core scheduler support improves the CPU scheduler's decision
1058	  making when dealing with multi-core CPU chips at a cost of slightly
1059	  increased overhead in some places. If unsure say N here.
1060
1061config SCHED_MC_PRIO
1062	bool "CPU core priorities scheduler support"
1063	depends on SCHED_MC
1064	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1065	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1066	select CPU_FREQ
1067	default y
1068	help
1069	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1070	  core ordering determined at manufacturing time, which allows
1071	  certain cores to reach higher turbo frequencies (when running
1072	  single threaded workloads) than others.
1073
1074	  Enabling this kernel feature teaches the scheduler about
1075	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1076	  scheduler's CPU selection logic accordingly, so that higher
1077	  overall system performance can be achieved.
1078
1079	  This feature will have no effect on CPUs without this feature.
1080
1081	  If unsure say Y here.
1082
1083config UP_LATE_INIT
1084	def_bool y
1085	depends on !SMP && X86_LOCAL_APIC
1086
1087config X86_UP_APIC
1088	bool "Local APIC support on uniprocessors" if !PCI_MSI
1089	default PCI_MSI
1090	depends on X86_32 && !SMP
1091	help
1092	  A local APIC (Advanced Programmable Interrupt Controller) is an
1093	  integrated interrupt controller in the CPU. If you have a single-CPU
1094	  system which has a processor with a local APIC, you can say Y here to
1095	  enable and use it. If you say Y here even though your machine doesn't
1096	  have a local APIC, then the kernel will still run with no slowdown at
1097	  all. The local APIC supports CPU-generated self-interrupts (timer,
1098	  performance counters), and the NMI watchdog which detects hard
1099	  lockups.
1100
1101config X86_UP_IOAPIC
1102	bool "IO-APIC support on uniprocessors"
1103	depends on X86_UP_APIC
1104	help
1105	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1106	  SMP-capable replacement for PC-style interrupt controllers. Most
1107	  SMP systems and many recent uniprocessor systems have one.
1108
1109	  If you have a single-CPU system with an IO-APIC, you can say Y here
1110	  to use it. If you say Y here even though your machine doesn't have
1111	  an IO-APIC, then the kernel will still run with no slowdown at all.
1112
1113config X86_LOCAL_APIC
1114	def_bool y
1115	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1116	select IRQ_DOMAIN_HIERARCHY
1117
1118config ACPI_MADT_WAKEUP
1119	def_bool y
1120	depends on X86_64
1121	depends on ACPI
1122	depends on SMP
1123	depends on X86_LOCAL_APIC
1124
1125config X86_IO_APIC
1126	def_bool y
1127	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1128
1129config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1130	bool "Reroute for broken boot IRQs"
1131	depends on X86_IO_APIC
1132	help
1133	  This option enables a workaround that fixes a source of
1134	  spurious interrupts. This is recommended when threaded
1135	  interrupt handling is used on systems where the generation of
1136	  superfluous "boot interrupts" cannot be disabled.
1137
1138	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1139	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1140	  kernel does during interrupt handling). On chipsets where this
1141	  boot IRQ generation cannot be disabled, this workaround keeps
1142	  the original IRQ line masked so that only the equivalent "boot
1143	  IRQ" is delivered to the CPUs. The workaround also tells the
1144	  kernel to set up the IRQ handler on the boot IRQ line. In this
1145	  way only one interrupt is delivered to the kernel. Otherwise
1146	  the spurious second interrupt may cause the kernel to bring
1147	  down (vital) interrupt lines.
1148
1149	  Only affects "broken" chipsets. Interrupt sharing may be
1150	  increased on these systems.
1151
1152config X86_MCE
1153	bool "Machine Check / overheating reporting"
1154	select GENERIC_ALLOCATOR
1155	default y
1156	help
1157	  Machine Check support allows the processor to notify the
1158	  kernel if it detects a problem (e.g. overheating, data corruption).
1159	  The action the kernel takes depends on the severity of the problem,
1160	  ranging from warning messages to halting the machine.
1161
1162config X86_MCELOG_LEGACY
1163	bool "Support for deprecated /dev/mcelog character device"
1164	depends on X86_MCE
1165	help
1166	  Enable support for /dev/mcelog which is needed by the old mcelog
1167	  userspace logging daemon. Consider switching to the new generation
1168	  rasdaemon solution.
1169
1170config X86_MCE_INTEL
1171	def_bool y
1172	prompt "Intel MCE features"
1173	depends on X86_MCE && X86_LOCAL_APIC
1174	help
1175	  Additional support for intel specific MCE features such as
1176	  the thermal monitor.
1177
1178config X86_MCE_AMD
1179	def_bool y
1180	prompt "AMD MCE features"
1181	depends on X86_MCE && X86_LOCAL_APIC
1182	help
1183	  Additional support for AMD specific MCE features such as
1184	  the DRAM Error Threshold.
1185
1186config X86_ANCIENT_MCE
1187	bool "Support for old Pentium 5 / WinChip machine checks"
1188	depends on X86_32 && X86_MCE
1189	help
1190	  Include support for machine check handling on old Pentium 5 or WinChip
1191	  systems. These typically need to be enabled explicitly on the command
1192	  line.
1193
1194config X86_MCE_THRESHOLD
1195	depends on X86_MCE_AMD || X86_MCE_INTEL
1196	def_bool y
1197
1198config X86_MCE_INJECT
1199	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1200	tristate "Machine check injector support"
1201	help
1202	  Provide support for injecting machine checks for testing purposes.
1203	  If you don't know what a machine check is and you don't do kernel
1204	  QA it is safe to say n.
1205
1206source "arch/x86/events/Kconfig"
1207
1208config X86_LEGACY_VM86
1209	bool "Legacy VM86 support"
1210	depends on X86_32
1211	help
1212	  This option allows user programs to put the CPU into V8086
1213	  mode, which is an 80286-era approximation of 16-bit real mode.
1214
1215	  Some very old versions of X and/or vbetool require this option
1216	  for user mode setting.  Similarly, DOSEMU will use it if
1217	  available to accelerate real mode DOS programs.  However, any
1218	  recent version of DOSEMU, X, or vbetool should be fully
1219	  functional even without kernel VM86 support, as they will all
1220	  fall back to software emulation. Nevertheless, if you are using
1221	  a 16-bit DOS program where 16-bit performance matters, vm86
1222	  mode might be faster than emulation and you might want to
1223	  enable this option.
1224
1225	  Note that any app that works on a 64-bit kernel is unlikely to
1226	  need this option, as 64-bit kernels don't, and can't, support
1227	  V8086 mode. This option is also unrelated to 16-bit protected
1228	  mode and is not needed to run most 16-bit programs under Wine.
1229
1230	  Enabling this option increases the complexity of the kernel
1231	  and slows down exception handling a tiny bit.
1232
1233	  If unsure, say N here.
1234
1235config VM86
1236	bool
1237	default X86_LEGACY_VM86
1238
1239config X86_16BIT
1240	bool "Enable support for 16-bit segments" if EXPERT
1241	default y
1242	depends on MODIFY_LDT_SYSCALL
1243	help
1244	  This option is required by programs like Wine to run 16-bit
1245	  protected mode legacy code on x86 processors.  Disabling
1246	  this option saves about 300 bytes on i386, or around 6K text
1247	  plus 16K runtime memory on x86-64,
1248
1249config X86_ESPFIX32
1250	def_bool y
1251	depends on X86_16BIT && X86_32
1252
1253config X86_ESPFIX64
1254	def_bool y
1255	depends on X86_16BIT && X86_64
1256
1257config X86_VSYSCALL_EMULATION
1258	bool "Enable vsyscall emulation" if EXPERT
1259	default y
1260	depends on X86_64
1261	help
1262	  This enables emulation of the legacy vsyscall page.  Disabling
1263	  it is roughly equivalent to booting with vsyscall=none, except
1264	  that it will also disable the helpful warning if a program
1265	  tries to use a vsyscall.  With this option set to N, offending
1266	  programs will just segfault, citing addresses of the form
1267	  0xffffffffff600?00.
1268
1269	  This option is required by many programs built before 2013, and
1270	  care should be used even with newer programs if set to N.
1271
1272	  Disabling this option saves about 7K of kernel size and
1273	  possibly 4K of additional runtime pagetable memory.
1274
1275config X86_IOPL_IOPERM
1276	bool "IOPERM and IOPL Emulation"
1277	default y
1278	help
1279	  This enables the ioperm() and iopl() syscalls which are necessary
1280	  for legacy applications.
1281
1282	  Legacy IOPL support is an overbroad mechanism which allows user
1283	  space aside of accessing all 65536 I/O ports also to disable
1284	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1285	  capabilities and permission from potentially active security
1286	  modules.
1287
1288	  The emulation restricts the functionality of the syscall to
1289	  only allowing the full range I/O port access, but prevents the
1290	  ability to disable interrupts from user space which would be
1291	  granted if the hardware IOPL mechanism would be used.
1292
1293config TOSHIBA
1294	tristate "Toshiba Laptop support"
1295	depends on X86_32
1296	help
1297	  This adds a driver to safely access the System Management Mode of
1298	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1299	  not work on models with a Phoenix BIOS. The System Management Mode
1300	  is used to set the BIOS and power saving options on Toshiba portables.
1301
1302	  For information on utilities to make use of this driver see the
1303	  Toshiba Linux utilities web site at:
1304	  <http://www.buzzard.org.uk/toshiba/>.
1305
1306	  Say Y if you intend to run this kernel on a Toshiba portable.
1307	  Say N otherwise.
1308
1309config X86_REBOOTFIXUPS
1310	bool "Enable X86 board specific fixups for reboot"
1311	depends on X86_32
1312	help
1313	  This enables chipset and/or board specific fixups to be done
1314	  in order to get reboot to work correctly. This is only needed on
1315	  some combinations of hardware and BIOS. The symptom, for which
1316	  this config is intended, is when reboot ends with a stalled/hung
1317	  system.
1318
1319	  Currently, the only fixup is for the Geode machines using
1320	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1321
1322	  Say Y if you want to enable the fixup. Currently, it's safe to
1323	  enable this option even if you don't need it.
1324	  Say N otherwise.
1325
1326config MICROCODE
1327	def_bool y
1328	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1329	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1330
1331config MICROCODE_INITRD32
1332	def_bool y
1333	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1334
1335config MICROCODE_LATE_LOADING
1336	bool "Late microcode loading (DANGEROUS)"
1337	default n
1338	depends on MICROCODE && SMP
1339	help
1340	  Loading microcode late, when the system is up and executing instructions
1341	  is a tricky business and should be avoided if possible. Just the sequence
1342	  of synchronizing all cores and SMT threads is one fragile dance which does
1343	  not guarantee that cores might not softlock after the loading. Therefore,
1344	  use this at your own risk. Late loading taints the kernel unless the
1345	  microcode header indicates that it is safe for late loading via the
1346	  minimal revision check. This minimal revision check can be enforced on
1347	  the kernel command line with "microcode.minrev=Y".
1348
1349config MICROCODE_LATE_FORCE_MINREV
1350	bool "Enforce late microcode loading minimal revision check"
1351	default n
1352	depends on MICROCODE_LATE_LOADING
1353	help
1354	  To prevent that users load microcode late which modifies already
1355	  in use features, newer microcode patches have a minimum revision field
1356	  in the microcode header, which tells the kernel which minimum
1357	  revision must be active in the CPU to safely load that new microcode
1358	  late into the running system. If disabled the check will not
1359	  be enforced but the kernel will be tainted when the minimal
1360	  revision check fails.
1361
1362	  This minimal revision check can also be controlled via the
1363	  "microcode.minrev" parameter on the kernel command line.
1364
1365	  If unsure say Y.
1366
1367config X86_MSR
1368	tristate "/dev/cpu/*/msr - Model-specific register support"
1369	help
1370	  This device gives privileged processes access to the x86
1371	  Model-Specific Registers (MSRs).  It is a character device with
1372	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1373	  MSR accesses are directed to a specific CPU on multi-processor
1374	  systems.
1375
1376config X86_CPUID
1377	tristate "/dev/cpu/*/cpuid - CPU information support"
1378	help
1379	  This device gives processes access to the x86 CPUID instruction to
1380	  be executed on a specific processor.  It is a character device
1381	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1382	  /dev/cpu/31/cpuid.
1383
1384config HIGHMEM4G
1385	bool "High Memory Support"
1386	depends on X86_32
1387	help
1388	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1389	  However, the address space of 32-bit x86 processors is only 4
1390	  Gigabytes large. That means that, if you have a large amount of
1391	  physical memory, not all of it can be "permanently mapped" by the
1392	  kernel. The physical memory that's not permanently mapped is called
1393	  "high memory".
1394
1395	  If you are compiling a kernel which will never run on a machine with
1396	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1397	  choice and suitable for most users). This will result in a "3GB/1GB"
1398	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1399	  space and the remaining part of the 4GB virtual memory space is used
1400	  by the kernel to permanently map as much physical memory as
1401	  possible.
1402
1403	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1404	  answer "Y" here.
1405
1406	  If unsure, say N.
1407
1408choice
1409	prompt "Memory split" if EXPERT
1410	default VMSPLIT_3G
1411	depends on X86_32
1412	help
1413	  Select the desired split between kernel and user memory.
1414
1415	  If the address range available to the kernel is less than the
1416	  physical memory installed, the remaining memory will be available
1417	  as "high memory". Accessing high memory is a little more costly
1418	  than low memory, as it needs to be mapped into the kernel first.
1419	  Note that increasing the kernel address space limits the range
1420	  available to user programs, making the address space there
1421	  tighter.  Selecting anything other than the default 3G/1G split
1422	  will also likely make your kernel incompatible with binary-only
1423	  kernel modules.
1424
1425	  If you are not absolutely sure what you are doing, leave this
1426	  option alone!
1427
1428	config VMSPLIT_3G
1429		bool "3G/1G user/kernel split"
1430	config VMSPLIT_3G_OPT
1431		depends on !X86_PAE
1432		bool "3G/1G user/kernel split (for full 1G low memory)"
1433	config VMSPLIT_2G
1434		bool "2G/2G user/kernel split"
1435	config VMSPLIT_2G_OPT
1436		depends on !X86_PAE
1437		bool "2G/2G user/kernel split (for full 2G low memory)"
1438	config VMSPLIT_1G
1439		bool "1G/3G user/kernel split"
1440endchoice
1441
1442config PAGE_OFFSET
1443	hex
1444	default 0xB0000000 if VMSPLIT_3G_OPT
1445	default 0x80000000 if VMSPLIT_2G
1446	default 0x78000000 if VMSPLIT_2G_OPT
1447	default 0x40000000 if VMSPLIT_1G
1448	default 0xC0000000
1449	depends on X86_32
1450
1451config HIGHMEM
1452	def_bool HIGHMEM4G
1453
1454config X86_PAE
1455	bool "PAE (Physical Address Extension) Support"
1456	depends on X86_32 && X86_HAVE_PAE
1457	select PHYS_ADDR_T_64BIT
1458	help
1459	  PAE is required for NX support, and furthermore enables
1460	  larger swapspace support for non-overcommit purposes. It
1461	  has the cost of more pagetable lookup overhead, and also
1462	  consumes more pagetable space per process.
1463
1464config X86_5LEVEL
1465	bool "Enable 5-level page tables support"
1466	default y
1467	select DYNAMIC_MEMORY_LAYOUT
1468	select SPARSEMEM_VMEMMAP
1469	depends on X86_64
1470	help
1471	  5-level paging enables access to larger address space:
1472	  up to 128 PiB of virtual address space and 4 PiB of
1473	  physical address space.
1474
1475	  It will be supported by future Intel CPUs.
1476
1477	  A kernel with the option enabled can be booted on machines that
1478	  support 4- or 5-level paging.
1479
1480	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1481	  information.
1482
1483	  Say N if unsure.
1484
1485config X86_DIRECT_GBPAGES
1486	def_bool y
1487	depends on X86_64
1488	help
1489	  Certain kernel features effectively disable kernel
1490	  linear 1 GB mappings (even if the CPU otherwise
1491	  supports them), so don't confuse the user by printing
1492	  that we have them enabled.
1493
1494config X86_CPA_STATISTICS
1495	bool "Enable statistic for Change Page Attribute"
1496	depends on DEBUG_FS
1497	help
1498	  Expose statistics about the Change Page Attribute mechanism, which
1499	  helps to determine the effectiveness of preserving large and huge
1500	  page mappings when mapping protections are changed.
1501
1502config X86_MEM_ENCRYPT
1503	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1504	select DYNAMIC_PHYSICAL_MASK
1505	def_bool n
1506
1507config AMD_MEM_ENCRYPT
1508	bool "AMD Secure Memory Encryption (SME) support"
1509	depends on X86_64 && CPU_SUP_AMD
1510	depends on EFI_STUB
1511	select DMA_COHERENT_POOL
1512	select ARCH_USE_MEMREMAP_PROT
1513	select INSTRUCTION_DECODER
1514	select ARCH_HAS_CC_PLATFORM
1515	select X86_MEM_ENCRYPT
1516	select UNACCEPTED_MEMORY
1517	select CRYPTO_LIB_AESGCM
1518	help
1519	  Say yes to enable support for the encryption of system memory.
1520	  This requires an AMD processor that supports Secure Memory
1521	  Encryption (SME).
1522
1523# Common NUMA Features
1524config NUMA
1525	bool "NUMA Memory Allocation and Scheduler Support"
1526	depends on SMP
1527	depends on X86_64
1528	select USE_PERCPU_NUMA_NODE_ID
1529	select OF_NUMA if OF
1530	help
1531	  Enable NUMA (Non-Uniform Memory Access) support.
1532
1533	  The kernel will try to allocate memory used by a CPU on the
1534	  local memory controller of the CPU and add some more
1535	  NUMA awareness to the kernel.
1536
1537	  For 64-bit this is recommended if the system is Intel Core i7
1538	  (or later), AMD Opteron, or EM64T NUMA.
1539
1540	  Otherwise, you should say N.
1541
1542config AMD_NUMA
1543	def_bool y
1544	prompt "Old style AMD Opteron NUMA detection"
1545	depends on X86_64 && NUMA && PCI
1546	help
1547	  Enable AMD NUMA node topology detection.  You should say Y here if
1548	  you have a multi processor AMD system. This uses an old method to
1549	  read the NUMA configuration directly from the builtin Northbridge
1550	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1551	  which also takes priority if both are compiled in.
1552
1553config X86_64_ACPI_NUMA
1554	def_bool y
1555	prompt "ACPI NUMA detection"
1556	depends on X86_64 && NUMA && ACPI && PCI
1557	select ACPI_NUMA
1558	help
1559	  Enable ACPI SRAT based node topology detection.
1560
1561config NODES_SHIFT
1562	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1563	range 1 10
1564	default "10" if MAXSMP
1565	default "6" if X86_64
1566	default "3"
1567	depends on NUMA
1568	help
1569	  Specify the maximum number of NUMA Nodes available on the target
1570	  system.  Increases memory reserved to accommodate various tables.
1571
1572config ARCH_FLATMEM_ENABLE
1573	def_bool y
1574	depends on X86_32 && !NUMA
1575
1576config ARCH_SPARSEMEM_ENABLE
1577	def_bool y
1578	select SPARSEMEM_STATIC if X86_32
1579	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1580
1581config ARCH_SPARSEMEM_DEFAULT
1582	def_bool X86_64 || (NUMA && X86_32)
1583
1584config ARCH_SELECT_MEMORY_MODEL
1585	def_bool y
1586	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1587
1588config ARCH_MEMORY_PROBE
1589	bool "Enable sysfs memory/probe interface"
1590	depends on MEMORY_HOTPLUG
1591	help
1592	  This option enables a sysfs memory/probe interface for testing.
1593	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1594	  If you are unsure how to answer this question, answer N.
1595
1596config ARCH_PROC_KCORE_TEXT
1597	def_bool y
1598	depends on X86_64 && PROC_KCORE
1599
1600config ILLEGAL_POINTER_VALUE
1601	hex
1602	default 0 if X86_32
1603	default 0xdead000000000000 if X86_64
1604
1605config X86_PMEM_LEGACY_DEVICE
1606	bool
1607
1608config X86_PMEM_LEGACY
1609	tristate "Support non-standard NVDIMMs and ADR protected memory"
1610	depends on PHYS_ADDR_T_64BIT
1611	depends on BLK_DEV
1612	select X86_PMEM_LEGACY_DEVICE
1613	select NUMA_KEEP_MEMINFO if NUMA
1614	select LIBNVDIMM
1615	help
1616	  Treat memory marked using the non-standard e820 type of 12 as used
1617	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1618	  The kernel will offer these regions to the 'pmem' driver so
1619	  they can be used for persistent storage.
1620
1621	  Say Y if unsure.
1622
1623config X86_CHECK_BIOS_CORRUPTION
1624	bool "Check for low memory corruption"
1625	help
1626	  Periodically check for memory corruption in low memory, which
1627	  is suspected to be caused by BIOS.  Even when enabled in the
1628	  configuration, it is disabled at runtime.  Enable it by
1629	  setting "memory_corruption_check=1" on the kernel command
1630	  line.  By default it scans the low 64k of memory every 60
1631	  seconds; see the memory_corruption_check_size and
1632	  memory_corruption_check_period parameters in
1633	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1634
1635	  When enabled with the default parameters, this option has
1636	  almost no overhead, as it reserves a relatively small amount
1637	  of memory and scans it infrequently.  It both detects corruption
1638	  and prevents it from affecting the running system.
1639
1640	  It is, however, intended as a diagnostic tool; if repeatable
1641	  BIOS-originated corruption always affects the same memory,
1642	  you can use memmap= to prevent the kernel from using that
1643	  memory.
1644
1645config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1646	bool "Set the default setting of memory_corruption_check"
1647	depends on X86_CHECK_BIOS_CORRUPTION
1648	default y
1649	help
1650	  Set whether the default state of memory_corruption_check is
1651	  on or off.
1652
1653config MATH_EMULATION
1654	bool
1655	depends on MODIFY_LDT_SYSCALL
1656	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1657	help
1658	  Linux can emulate a math coprocessor (used for floating point
1659	  operations) if you don't have one. 486DX and Pentium processors have
1660	  a math coprocessor built in, 486SX and 386 do not, unless you added
1661	  a 487DX or 387, respectively. (The messages during boot time can
1662	  give you some hints here ["man dmesg"].) Everyone needs either a
1663	  coprocessor or this emulation.
1664
1665	  If you don't have a math coprocessor, you need to say Y here; if you
1666	  say Y here even though you have a coprocessor, the coprocessor will
1667	  be used nevertheless. (This behavior can be changed with the kernel
1668	  command line option "no387", which comes handy if your coprocessor
1669	  is broken. Try "man bootparam" or see the documentation of your boot
1670	  loader (lilo or loadlin) about how to pass options to the kernel at
1671	  boot time.) This means that it is a good idea to say Y here if you
1672	  intend to use this kernel on different machines.
1673
1674	  More information about the internals of the Linux math coprocessor
1675	  emulation can be found in <file:arch/x86/math-emu/README>.
1676
1677	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1678	  kernel, it won't hurt.
1679
1680config MTRR
1681	def_bool y
1682	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1683	help
1684	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1685	  the Memory Type Range Registers (MTRRs) may be used to control
1686	  processor access to memory ranges. This is most useful if you have
1687	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1688	  allows bus write transfers to be combined into a larger transfer
1689	  before bursting over the PCI/AGP bus. This can increase performance
1690	  of image write operations 2.5 times or more. Saying Y here creates a
1691	  /proc/mtrr file which may be used to manipulate your processor's
1692	  MTRRs. Typically the X server should use this.
1693
1694	  This code has a reasonably generic interface so that similar
1695	  control registers on other processors can be easily supported
1696	  as well:
1697
1698	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1699	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1700	  these, the ARRs are used to emulate the MTRRs.
1701	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1702	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1703	  write-combining. All of these processors are supported by this code
1704	  and it makes sense to say Y here if you have one of them.
1705
1706	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1707	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1708	  can lead to all sorts of problems, so it's good to say Y here.
1709
1710	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1711	  just add about 9 KB to your kernel.
1712
1713	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1714
1715config MTRR_SANITIZER
1716	def_bool y
1717	prompt "MTRR cleanup support"
1718	depends on MTRR
1719	help
1720	  Convert MTRR layout from continuous to discrete, so X drivers can
1721	  add writeback entries.
1722
1723	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1724	  The largest mtrr entry size for a continuous block can be set with
1725	  mtrr_chunk_size.
1726
1727	  If unsure, say Y.
1728
1729config MTRR_SANITIZER_ENABLE_DEFAULT
1730	int "MTRR cleanup enable value (0-1)"
1731	range 0 1
1732	default "0"
1733	depends on MTRR_SANITIZER
1734	help
1735	  Enable mtrr cleanup default value
1736
1737config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1738	int "MTRR cleanup spare reg num (0-7)"
1739	range 0 7
1740	default "1"
1741	depends on MTRR_SANITIZER
1742	help
1743	  mtrr cleanup spare entries default, it can be changed via
1744	  mtrr_spare_reg_nr=N on the kernel command line.
1745
1746config X86_PAT
1747	def_bool y
1748	prompt "x86 PAT support" if EXPERT
1749	depends on MTRR
1750	select ARCH_USES_PG_ARCH_2
1751	help
1752	  Use PAT attributes to setup page level cache control.
1753
1754	  PATs are the modern equivalents of MTRRs and are much more
1755	  flexible than MTRRs.
1756
1757	  Say N here if you see bootup problems (boot crash, boot hang,
1758	  spontaneous reboots) or a non-working video driver.
1759
1760	  If unsure, say Y.
1761
1762config X86_UMIP
1763	def_bool y
1764	prompt "User Mode Instruction Prevention" if EXPERT
1765	help
1766	  User Mode Instruction Prevention (UMIP) is a security feature in
1767	  some x86 processors. If enabled, a general protection fault is
1768	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1769	  executed in user mode. These instructions unnecessarily expose
1770	  information about the hardware state.
1771
1772	  The vast majority of applications do not use these instructions.
1773	  For the very few that do, software emulation is provided in
1774	  specific cases in protected and virtual-8086 modes. Emulated
1775	  results are dummy.
1776
1777config CC_HAS_IBT
1778	# GCC >= 9 and binutils >= 2.29
1779	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1780	# Clang/LLVM >= 14
1781	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1782	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1783	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1784		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1785		  $(as-instr,endbr64)
1786
1787config X86_CET
1788	def_bool n
1789	help
1790	  CET features configured (Shadow stack or IBT)
1791
1792config X86_KERNEL_IBT
1793	prompt "Indirect Branch Tracking"
1794	def_bool y
1795	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1796	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1797	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1798	select OBJTOOL
1799	select X86_CET
1800	help
1801	  Build the kernel with support for Indirect Branch Tracking, a
1802	  hardware support course-grain forward-edge Control Flow Integrity
1803	  protection. It enforces that all indirect calls must land on
1804	  an ENDBR instruction, as such, the compiler will instrument the
1805	  code with them to make this happen.
1806
1807	  In addition to building the kernel with IBT, seal all functions that
1808	  are not indirect call targets, avoiding them ever becoming one.
1809
1810	  This requires LTO like objtool runs and will slow down the build. It
1811	  does significantly reduce the number of ENDBR instructions in the
1812	  kernel image.
1813
1814config X86_INTEL_MEMORY_PROTECTION_KEYS
1815	prompt "Memory Protection Keys"
1816	def_bool y
1817	# Note: only available in 64-bit mode
1818	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1819	select ARCH_USES_HIGH_VMA_FLAGS
1820	select ARCH_HAS_PKEYS
1821	help
1822	  Memory Protection Keys provides a mechanism for enforcing
1823	  page-based protections, but without requiring modification of the
1824	  page tables when an application changes protection domains.
1825
1826	  For details, see Documentation/core-api/protection-keys.rst
1827
1828	  If unsure, say y.
1829
1830config ARCH_PKEY_BITS
1831	int
1832	default 4
1833
1834choice
1835	prompt "TSX enable mode"
1836	depends on CPU_SUP_INTEL
1837	default X86_INTEL_TSX_MODE_OFF
1838	help
1839	  Intel's TSX (Transactional Synchronization Extensions) feature
1840	  allows to optimize locking protocols through lock elision which
1841	  can lead to a noticeable performance boost.
1842
1843	  On the other hand it has been shown that TSX can be exploited
1844	  to form side channel attacks (e.g. TAA) and chances are there
1845	  will be more of those attacks discovered in the future.
1846
1847	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1848	  might override this decision by tsx=on the command line parameter.
1849	  Even with TSX enabled, the kernel will attempt to enable the best
1850	  possible TAA mitigation setting depending on the microcode available
1851	  for the particular machine.
1852
1853	  This option allows to set the default tsx mode between tsx=on, =off
1854	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1855	  details.
1856
1857	  Say off if not sure, auto if TSX is in use but it should be used on safe
1858	  platforms or on if TSX is in use and the security aspect of tsx is not
1859	  relevant.
1860
1861config X86_INTEL_TSX_MODE_OFF
1862	bool "off"
1863	help
1864	  TSX is disabled if possible - equals to tsx=off command line parameter.
1865
1866config X86_INTEL_TSX_MODE_ON
1867	bool "on"
1868	help
1869	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1870	  line parameter.
1871
1872config X86_INTEL_TSX_MODE_AUTO
1873	bool "auto"
1874	help
1875	  TSX is enabled on TSX capable HW that is believed to be safe against
1876	  side channel attacks- equals the tsx=auto command line parameter.
1877endchoice
1878
1879config X86_SGX
1880	bool "Software Guard eXtensions (SGX)"
1881	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1882	depends on CRYPTO=y
1883	depends on CRYPTO_SHA256=y
1884	select MMU_NOTIFIER
1885	select NUMA_KEEP_MEMINFO if NUMA
1886	select XARRAY_MULTI
1887	help
1888	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1889	  that can be used by applications to set aside private regions of code
1890	  and data, referred to as enclaves. An enclave's private memory can
1891	  only be accessed by code running within the enclave. Accesses from
1892	  outside the enclave, including other enclaves, are disallowed by
1893	  hardware.
1894
1895	  If unsure, say N.
1896
1897config X86_USER_SHADOW_STACK
1898	bool "X86 userspace shadow stack"
1899	depends on AS_WRUSS
1900	depends on X86_64
1901	select ARCH_USES_HIGH_VMA_FLAGS
1902	select ARCH_HAS_USER_SHADOW_STACK
1903	select X86_CET
1904	help
1905	  Shadow stack protection is a hardware feature that detects function
1906	  return address corruption.  This helps mitigate ROP attacks.
1907	  Applications must be enabled to use it, and old userspace does not
1908	  get protection "for free".
1909
1910	  CPUs supporting shadow stacks were first released in 2020.
1911
1912	  See Documentation/arch/x86/shstk.rst for more information.
1913
1914	  If unsure, say N.
1915
1916config INTEL_TDX_HOST
1917	bool "Intel Trust Domain Extensions (TDX) host support"
1918	depends on CPU_SUP_INTEL
1919	depends on X86_64
1920	depends on KVM_INTEL
1921	depends on X86_X2APIC
1922	select ARCH_KEEP_MEMBLOCK
1923	depends on CONTIG_ALLOC
1924	depends on !KEXEC_CORE
1925	depends on X86_MCE
1926	help
1927	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1928	  host and certain physical attacks.  This option enables necessary TDX
1929	  support in the host kernel to run confidential VMs.
1930
1931	  If unsure, say N.
1932
1933config EFI
1934	bool "EFI runtime service support"
1935	depends on ACPI
1936	select UCS2_STRING
1937	select EFI_RUNTIME_WRAPPERS
1938	select ARCH_USE_MEMREMAP_PROT
1939	select EFI_RUNTIME_MAP if KEXEC_CORE
1940	help
1941	  This enables the kernel to use EFI runtime services that are
1942	  available (such as the EFI variable services).
1943
1944	  This option is only useful on systems that have EFI firmware.
1945	  In addition, you should use the latest ELILO loader available
1946	  at <http://elilo.sourceforge.net> in order to take advantage
1947	  of EFI runtime services. However, even with this option, the
1948	  resultant kernel should continue to boot on existing non-EFI
1949	  platforms.
1950
1951config EFI_STUB
1952	bool "EFI stub support"
1953	depends on EFI
1954	select RELOCATABLE
1955	help
1956	  This kernel feature allows a bzImage to be loaded directly
1957	  by EFI firmware without the use of a bootloader.
1958
1959	  See Documentation/admin-guide/efi-stub.rst for more information.
1960
1961config EFI_HANDOVER_PROTOCOL
1962	bool "EFI handover protocol (DEPRECATED)"
1963	depends on EFI_STUB
1964	default y
1965	help
1966	  Select this in order to include support for the deprecated EFI
1967	  handover protocol, which defines alternative entry points into the
1968	  EFI stub.  This is a practice that has no basis in the UEFI
1969	  specification, and requires a priori knowledge on the part of the
1970	  bootloader about Linux/x86 specific ways of passing the command line
1971	  and initrd, and where in memory those assets may be loaded.
1972
1973	  If in doubt, say Y. Even though the corresponding support is not
1974	  present in upstream GRUB or other bootloaders, most distros build
1975	  GRUB with numerous downstream patches applied, and may rely on the
1976	  handover protocol as as result.
1977
1978config EFI_MIXED
1979	bool "EFI mixed-mode support"
1980	depends on EFI_STUB && X86_64
1981	help
1982	  Enabling this feature allows a 64-bit kernel to be booted
1983	  on a 32-bit firmware, provided that your CPU supports 64-bit
1984	  mode.
1985
1986	  Note that it is not possible to boot a mixed-mode enabled
1987	  kernel via the EFI boot stub - a bootloader that supports
1988	  the EFI handover protocol must be used.
1989
1990	  If unsure, say N.
1991
1992config EFI_RUNTIME_MAP
1993	bool "Export EFI runtime maps to sysfs" if EXPERT
1994	depends on EFI
1995	help
1996	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1997	  That memory map is required by the 2nd kernel to set up EFI virtual
1998	  mappings after kexec, but can also be used for debugging purposes.
1999
2000	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2001
2002source "kernel/Kconfig.hz"
2003
2004config ARCH_SUPPORTS_KEXEC
2005	def_bool y
2006
2007config ARCH_SUPPORTS_KEXEC_FILE
2008	def_bool X86_64
2009
2010config ARCH_SELECTS_KEXEC_FILE
2011	def_bool y
2012	depends on KEXEC_FILE
2013	select HAVE_IMA_KEXEC if IMA
2014
2015config ARCH_SUPPORTS_KEXEC_PURGATORY
2016	def_bool y
2017
2018config ARCH_SUPPORTS_KEXEC_SIG
2019	def_bool y
2020
2021config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2022	def_bool y
2023
2024config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2025	def_bool y
2026
2027config ARCH_SUPPORTS_KEXEC_JUMP
2028	def_bool y
2029
2030config ARCH_SUPPORTS_CRASH_DUMP
2031	def_bool X86_64 || (X86_32 && HIGHMEM)
2032
2033config ARCH_DEFAULT_CRASH_DUMP
2034	def_bool y
2035
2036config ARCH_SUPPORTS_CRASH_HOTPLUG
2037	def_bool y
2038
2039config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2040	def_bool CRASH_RESERVE
2041
2042config PHYSICAL_START
2043	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2044	default "0x1000000"
2045	help
2046	  This gives the physical address where the kernel is loaded.
2047
2048	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2049	  will decompress itself to above physical address and run from there.
2050	  Otherwise, bzImage will run from the address where it has been loaded
2051	  by the boot loader. The only exception is if it is loaded below the
2052	  above physical address, in which case it will relocate itself there.
2053
2054	  In normal kdump cases one does not have to set/change this option
2055	  as now bzImage can be compiled as a completely relocatable image
2056	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2057	  address. This option is mainly useful for the folks who don't want
2058	  to use a bzImage for capturing the crash dump and want to use a
2059	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2060	  to be specifically compiled to run from a specific memory area
2061	  (normally a reserved region) and this option comes handy.
2062
2063	  So if you are using bzImage for capturing the crash dump,
2064	  leave the value here unchanged to 0x1000000 and set
2065	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2066	  for capturing the crash dump change this value to start of
2067	  the reserved region.  In other words, it can be set based on
2068	  the "X" value as specified in the "crashkernel=YM@XM"
2069	  command line boot parameter passed to the panic-ed
2070	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2071	  for more details about crash dumps.
2072
2073	  Usage of bzImage for capturing the crash dump is recommended as
2074	  one does not have to build two kernels. Same kernel can be used
2075	  as production kernel and capture kernel. Above option should have
2076	  gone away after relocatable bzImage support is introduced. But it
2077	  is present because there are users out there who continue to use
2078	  vmlinux for dump capture. This option should go away down the
2079	  line.
2080
2081	  Don't change this unless you know what you are doing.
2082
2083config RELOCATABLE
2084	bool "Build a relocatable kernel"
2085	default y
2086	help
2087	  This builds a kernel image that retains relocation information
2088	  so it can be loaded someplace besides the default 1MB.
2089	  The relocations tend to make the kernel binary about 10% larger,
2090	  but are discarded at runtime.
2091
2092	  One use is for the kexec on panic case where the recovery kernel
2093	  must live at a different physical address than the primary
2094	  kernel.
2095
2096	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2097	  it has been loaded at and the compile time physical address
2098	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2099
2100config RANDOMIZE_BASE
2101	bool "Randomize the address of the kernel image (KASLR)"
2102	depends on RELOCATABLE
2103	default y
2104	help
2105	  In support of Kernel Address Space Layout Randomization (KASLR),
2106	  this randomizes the physical address at which the kernel image
2107	  is decompressed and the virtual address where the kernel
2108	  image is mapped, as a security feature that deters exploit
2109	  attempts relying on knowledge of the location of kernel
2110	  code internals.
2111
2112	  On 64-bit, the kernel physical and virtual addresses are
2113	  randomized separately. The physical address will be anywhere
2114	  between 16MB and the top of physical memory (up to 64TB). The
2115	  virtual address will be randomized from 16MB up to 1GB (9 bits
2116	  of entropy). Note that this also reduces the memory space
2117	  available to kernel modules from 1.5GB to 1GB.
2118
2119	  On 32-bit, the kernel physical and virtual addresses are
2120	  randomized together. They will be randomized from 16MB up to
2121	  512MB (8 bits of entropy).
2122
2123	  Entropy is generated using the RDRAND instruction if it is
2124	  supported. If RDTSC is supported, its value is mixed into
2125	  the entropy pool as well. If neither RDRAND nor RDTSC are
2126	  supported, then entropy is read from the i8254 timer. The
2127	  usable entropy is limited by the kernel being built using
2128	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2129	  minimum of 2MB. As a result, only 10 bits of entropy are
2130	  theoretically possible, but the implementations are further
2131	  limited due to memory layouts.
2132
2133	  If unsure, say Y.
2134
2135# Relocation on x86 needs some additional build support
2136config X86_NEED_RELOCS
2137	def_bool y
2138	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2139
2140config PHYSICAL_ALIGN
2141	hex "Alignment value to which kernel should be aligned"
2142	default "0x200000"
2143	range 0x2000 0x1000000 if X86_32
2144	range 0x200000 0x1000000 if X86_64
2145	help
2146	  This value puts the alignment restrictions on physical address
2147	  where kernel is loaded and run from. Kernel is compiled for an
2148	  address which meets above alignment restriction.
2149
2150	  If bootloader loads the kernel at a non-aligned address and
2151	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2152	  address aligned to above value and run from there.
2153
2154	  If bootloader loads the kernel at a non-aligned address and
2155	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2156	  load address and decompress itself to the address it has been
2157	  compiled for and run from there. The address for which kernel is
2158	  compiled already meets above alignment restrictions. Hence the
2159	  end result is that kernel runs from a physical address meeting
2160	  above alignment restrictions.
2161
2162	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2163	  this value must be a multiple of 0x200000.
2164
2165	  Don't change this unless you know what you are doing.
2166
2167config DYNAMIC_MEMORY_LAYOUT
2168	bool
2169	help
2170	  This option makes base addresses of vmalloc and vmemmap as well as
2171	  __PAGE_OFFSET movable during boot.
2172
2173config RANDOMIZE_MEMORY
2174	bool "Randomize the kernel memory sections"
2175	depends on X86_64
2176	depends on RANDOMIZE_BASE
2177	select DYNAMIC_MEMORY_LAYOUT
2178	default RANDOMIZE_BASE
2179	help
2180	  Randomizes the base virtual address of kernel memory sections
2181	  (physical memory mapping, vmalloc & vmemmap). This security feature
2182	  makes exploits relying on predictable memory locations less reliable.
2183
2184	  The order of allocations remains unchanged. Entropy is generated in
2185	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2186	  configuration have in average 30,000 different possible virtual
2187	  addresses for each memory section.
2188
2189	  If unsure, say Y.
2190
2191config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2192	hex "Physical memory mapping padding" if EXPERT
2193	depends on RANDOMIZE_MEMORY
2194	default "0xa" if MEMORY_HOTPLUG
2195	default "0x0"
2196	range 0x1 0x40 if MEMORY_HOTPLUG
2197	range 0x0 0x40
2198	help
2199	  Define the padding in terabytes added to the existing physical
2200	  memory size during kernel memory randomization. It is useful
2201	  for memory hotplug support but reduces the entropy available for
2202	  address randomization.
2203
2204	  If unsure, leave at the default value.
2205
2206config ADDRESS_MASKING
2207	bool "Linear Address Masking support"
2208	depends on X86_64
2209	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2210	help
2211	  Linear Address Masking (LAM) modifies the checking that is applied
2212	  to 64-bit linear addresses, allowing software to use of the
2213	  untranslated address bits for metadata.
2214
2215	  The capability can be used for efficient address sanitizers (ASAN)
2216	  implementation and for optimizations in JITs.
2217
2218config HOTPLUG_CPU
2219	def_bool y
2220	depends on SMP
2221
2222config COMPAT_VDSO
2223	def_bool n
2224	prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)"
2225	depends on COMPAT_32
2226	help
2227	  Certain buggy versions of glibc will crash if they are
2228	  presented with a 32-bit vDSO that is not mapped at the address
2229	  indicated in its segment table.
2230
2231	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2232	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2233	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2234	  the only released version with the bug, but OpenSUSE 9
2235	  contains a buggy "glibc 2.3.2".
2236
2237	  The symptom of the bug is that everything crashes on startup, saying:
2238	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2239
2240	  Saying Y here changes the default value of the vdso32 boot
2241	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2242	  This works around the glibc bug but hurts performance.
2243
2244	  If unsure, say N: if you are compiling your own kernel, you
2245	  are unlikely to be using a buggy version of glibc.
2246
2247choice
2248	prompt "vsyscall table for legacy applications"
2249	depends on X86_64
2250	default LEGACY_VSYSCALL_XONLY
2251	help
2252	  Legacy user code that does not know how to find the vDSO expects
2253	  to be able to issue three syscalls by calling fixed addresses in
2254	  kernel space. Since this location is not randomized with ASLR,
2255	  it can be used to assist security vulnerability exploitation.
2256
2257	  This setting can be changed at boot time via the kernel command
2258	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2259	  is deprecated and can only be enabled using the kernel command
2260	  line.
2261
2262	  On a system with recent enough glibc (2.14 or newer) and no
2263	  static binaries, you can say None without a performance penalty
2264	  to improve security.
2265
2266	  If unsure, select "Emulate execution only".
2267
2268	config LEGACY_VSYSCALL_XONLY
2269		bool "Emulate execution only"
2270		help
2271		  The kernel traps and emulates calls into the fixed vsyscall
2272		  address mapping and does not allow reads.  This
2273		  configuration is recommended when userspace might use the
2274		  legacy vsyscall area but support for legacy binary
2275		  instrumentation of legacy code is not needed.  It mitigates
2276		  certain uses of the vsyscall area as an ASLR-bypassing
2277		  buffer.
2278
2279	config LEGACY_VSYSCALL_NONE
2280		bool "None"
2281		help
2282		  There will be no vsyscall mapping at all. This will
2283		  eliminate any risk of ASLR bypass due to the vsyscall
2284		  fixed address mapping. Attempts to use the vsyscalls
2285		  will be reported to dmesg, so that either old or
2286		  malicious userspace programs can be identified.
2287
2288endchoice
2289
2290config CMDLINE_BOOL
2291	bool "Built-in kernel command line"
2292	help
2293	  Allow for specifying boot arguments to the kernel at
2294	  build time.  On some systems (e.g. embedded ones), it is
2295	  necessary or convenient to provide some or all of the
2296	  kernel boot arguments with the kernel itself (that is,
2297	  to not rely on the boot loader to provide them.)
2298
2299	  To compile command line arguments into the kernel,
2300	  set this option to 'Y', then fill in the
2301	  boot arguments in CONFIG_CMDLINE.
2302
2303	  Systems with fully functional boot loaders (i.e. non-embedded)
2304	  should leave this option set to 'N'.
2305
2306config CMDLINE
2307	string "Built-in kernel command string"
2308	depends on CMDLINE_BOOL
2309	default ""
2310	help
2311	  Enter arguments here that should be compiled into the kernel
2312	  image and used at boot time.  If the boot loader provides a
2313	  command line at boot time, it is appended to this string to
2314	  form the full kernel command line, when the system boots.
2315
2316	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2317	  change this behavior.
2318
2319	  In most cases, the command line (whether built-in or provided
2320	  by the boot loader) should specify the device for the root
2321	  file system.
2322
2323config CMDLINE_OVERRIDE
2324	bool "Built-in command line overrides boot loader arguments"
2325	depends on CMDLINE_BOOL && CMDLINE != ""
2326	help
2327	  Set this option to 'Y' to have the kernel ignore the boot loader
2328	  command line, and use ONLY the built-in command line.
2329
2330	  This is used to work around broken boot loaders.  This should
2331	  be set to 'N' under normal conditions.
2332
2333config MODIFY_LDT_SYSCALL
2334	bool "Enable the LDT (local descriptor table)" if EXPERT
2335	default y
2336	help
2337	  Linux can allow user programs to install a per-process x86
2338	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2339	  call.  This is required to run 16-bit or segmented code such as
2340	  DOSEMU or some Wine programs.  It is also used by some very old
2341	  threading libraries.
2342
2343	  Enabling this feature adds a small amount of overhead to
2344	  context switches and increases the low-level kernel attack
2345	  surface.  Disabling it removes the modify_ldt(2) system call.
2346
2347	  Saying 'N' here may make sense for embedded or server kernels.
2348
2349config STRICT_SIGALTSTACK_SIZE
2350	bool "Enforce strict size checking for sigaltstack"
2351	depends on DYNAMIC_SIGFRAME
2352	help
2353	  For historical reasons MINSIGSTKSZ is a constant which became
2354	  already too small with AVX512 support. Add a mechanism to
2355	  enforce strict checking of the sigaltstack size against the
2356	  real size of the FPU frame. This option enables the check
2357	  by default. It can also be controlled via the kernel command
2358	  line option 'strict_sas_size' independent of this config
2359	  switch. Enabling it might break existing applications which
2360	  allocate a too small sigaltstack but 'work' because they
2361	  never get a signal delivered.
2362
2363	  Say 'N' unless you want to really enforce this check.
2364
2365config CFI_AUTO_DEFAULT
2366	bool "Attempt to use FineIBT by default at boot time"
2367	depends on FINEIBT
2368	default y
2369	help
2370	  Attempt to use FineIBT by default at boot time. If enabled,
2371	  this is the same as booting with "cfi=auto". If disabled,
2372	  this is the same as booting with "cfi=kcfi".
2373
2374source "kernel/livepatch/Kconfig"
2375
2376config X86_BUS_LOCK_DETECT
2377	bool "Split Lock Detect and Bus Lock Detect support"
2378	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2379	default y
2380	help
2381	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2382	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2383
2384endmenu
2385
2386config CC_HAS_NAMED_AS
2387	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2388	depends on CC_IS_GCC
2389
2390#
2391# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2392# are incompatible with named address spaces with GCC < 13.3
2393# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2394#
2395
2396config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2397	def_bool y
2398	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2399	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2400
2401config USE_X86_SEG_SUPPORT
2402	def_bool CC_HAS_NAMED_AS
2403	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2404
2405config CC_HAS_SLS
2406	def_bool $(cc-option,-mharden-sls=all)
2407
2408config CC_HAS_RETURN_THUNK
2409	def_bool $(cc-option,-mfunction-return=thunk-extern)
2410
2411config CC_HAS_ENTRY_PADDING
2412	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2413
2414config CC_HAS_KCFI_ARITY
2415	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2416	depends on CC_IS_CLANG && !RUST
2417
2418config FUNCTION_PADDING_CFI
2419	int
2420	default 59 if FUNCTION_ALIGNMENT_64B
2421	default 27 if FUNCTION_ALIGNMENT_32B
2422	default 11 if FUNCTION_ALIGNMENT_16B
2423	default  3 if FUNCTION_ALIGNMENT_8B
2424	default  0
2425
2426# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2427# except Kconfig can't do arithmetic :/
2428config FUNCTION_PADDING_BYTES
2429	int
2430	default FUNCTION_PADDING_CFI if CFI_CLANG
2431	default FUNCTION_ALIGNMENT
2432
2433config CALL_PADDING
2434	def_bool n
2435	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2436	select FUNCTION_ALIGNMENT_16B
2437
2438config FINEIBT
2439	def_bool y
2440	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
2441	select CALL_PADDING
2442
2443config FINEIBT_BHI
2444	def_bool y
2445	depends on FINEIBT && CC_HAS_KCFI_ARITY
2446
2447config HAVE_CALL_THUNKS
2448	def_bool y
2449	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2450
2451config CALL_THUNKS
2452	def_bool n
2453	select CALL_PADDING
2454
2455config PREFIX_SYMBOLS
2456	def_bool y
2457	depends on CALL_PADDING && !CFI_CLANG
2458
2459menuconfig CPU_MITIGATIONS
2460	bool "Mitigations for CPU vulnerabilities"
2461	default y
2462	help
2463	  Say Y here to enable options which enable mitigations for hardware
2464	  vulnerabilities (usually related to speculative execution).
2465	  Mitigations can be disabled or restricted to SMT systems at runtime
2466	  via the "mitigations" kernel parameter.
2467
2468	  If you say N, all mitigations will be disabled.  This CANNOT be
2469	  overridden at runtime.
2470
2471	  Say 'Y', unless you really know what you are doing.
2472
2473if CPU_MITIGATIONS
2474
2475config MITIGATION_PAGE_TABLE_ISOLATION
2476	bool "Remove the kernel mapping in user mode"
2477	default y
2478	depends on (X86_64 || X86_PAE)
2479	help
2480	  This feature reduces the number of hardware side channels by
2481	  ensuring that the majority of kernel addresses are not mapped
2482	  into userspace.
2483
2484	  See Documentation/arch/x86/pti.rst for more details.
2485
2486config MITIGATION_RETPOLINE
2487	bool "Avoid speculative indirect branches in kernel"
2488	select OBJTOOL if HAVE_OBJTOOL
2489	default y
2490	help
2491	  Compile kernel with the retpoline compiler options to guard against
2492	  kernel-to-user data leaks by avoiding speculative indirect
2493	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2494	  support for full protection. The kernel may run slower.
2495
2496config MITIGATION_RETHUNK
2497	bool "Enable return-thunks"
2498	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2499	select OBJTOOL if HAVE_OBJTOOL
2500	default y if X86_64
2501	help
2502	  Compile the kernel with the return-thunks compiler option to guard
2503	  against kernel-to-user data leaks by avoiding return speculation.
2504	  Requires a compiler with -mfunction-return=thunk-extern
2505	  support for full protection. The kernel may run slower.
2506
2507config MITIGATION_UNRET_ENTRY
2508	bool "Enable UNRET on kernel entry"
2509	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2510	default y
2511	help
2512	  Compile the kernel with support for the retbleed=unret mitigation.
2513
2514config MITIGATION_CALL_DEPTH_TRACKING
2515	bool "Mitigate RSB underflow with call depth tracking"
2516	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2517	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2518	select CALL_THUNKS
2519	default y
2520	help
2521	  Compile the kernel with call depth tracking to mitigate the Intel
2522	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2523	  by default and needs to be enabled on the kernel command line via the
2524	  retbleed=stuff option. For non-affected systems the overhead of this
2525	  option is marginal as the call depth tracking is using run-time
2526	  generated call thunks in a compiler generated padding area and call
2527	  patching. This increases text size by ~5%. For non affected systems
2528	  this space is unused. On affected SKL systems this results in a
2529	  significant performance gain over the IBRS mitigation.
2530
2531config CALL_THUNKS_DEBUG
2532	bool "Enable call thunks and call depth tracking debugging"
2533	depends on MITIGATION_CALL_DEPTH_TRACKING
2534	select FUNCTION_ALIGNMENT_32B
2535	default n
2536	help
2537	  Enable call/ret counters for imbalance detection and build in
2538	  a noisy dmesg about callthunks generation and call patching for
2539	  trouble shooting. The debug prints need to be enabled on the
2540	  kernel command line with 'debug-callthunks'.
2541	  Only enable this when you are debugging call thunks as this
2542	  creates a noticeable runtime overhead. If unsure say N.
2543
2544config MITIGATION_IBPB_ENTRY
2545	bool "Enable IBPB on kernel entry"
2546	depends on CPU_SUP_AMD && X86_64
2547	default y
2548	help
2549	  Compile the kernel with support for the retbleed=ibpb and
2550	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2551
2552config MITIGATION_IBRS_ENTRY
2553	bool "Enable IBRS on kernel entry"
2554	depends on CPU_SUP_INTEL && X86_64
2555	default y
2556	help
2557	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2558	  This mitigates both spectre_v2 and retbleed at great cost to
2559	  performance.
2560
2561config MITIGATION_SRSO
2562	bool "Mitigate speculative RAS overflow on AMD"
2563	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2564	default y
2565	help
2566	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2567
2568config MITIGATION_SLS
2569	bool "Mitigate Straight-Line-Speculation"
2570	depends on CC_HAS_SLS && X86_64
2571	select OBJTOOL if HAVE_OBJTOOL
2572	default n
2573	help
2574	  Compile the kernel with straight-line-speculation options to guard
2575	  against straight line speculation. The kernel image might be slightly
2576	  larger.
2577
2578config MITIGATION_GDS
2579	bool "Mitigate Gather Data Sampling"
2580	depends on CPU_SUP_INTEL
2581	default y
2582	help
2583	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2584	  vulnerability which allows unprivileged speculative access to data
2585	  which was previously stored in vector registers. The attacker uses gather
2586	  instructions to infer the stale vector register data.
2587
2588config MITIGATION_RFDS
2589	bool "RFDS Mitigation"
2590	depends on CPU_SUP_INTEL
2591	default y
2592	help
2593	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2594	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2595	  allows unprivileged speculative access to stale data previously
2596	  stored in floating point, vector and integer registers.
2597	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2598
2599config MITIGATION_SPECTRE_BHI
2600	bool "Mitigate Spectre-BHB (Branch History Injection)"
2601	depends on CPU_SUP_INTEL
2602	default y
2603	help
2604	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2605	  where the branch history buffer is poisoned to speculatively steer
2606	  indirect branches.
2607	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2608
2609config MITIGATION_MDS
2610	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2611	depends on CPU_SUP_INTEL
2612	default y
2613	help
2614	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2615	  a hardware vulnerability which allows unprivileged speculative access
2616	  to data which is available in various CPU internal buffers.
2617	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2618
2619config MITIGATION_TAA
2620	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2621	depends on CPU_SUP_INTEL
2622	default y
2623	help
2624	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2625	  vulnerability that allows unprivileged speculative access to data
2626	  which is available in various CPU internal buffers by using
2627	  asynchronous aborts within an Intel TSX transactional region.
2628	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2629
2630config MITIGATION_MMIO_STALE_DATA
2631	bool "Mitigate MMIO Stale Data hardware bug"
2632	depends on CPU_SUP_INTEL
2633	default y
2634	help
2635	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2636	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2637	  vulnerabilities that can expose data. The vulnerabilities require the
2638	  attacker to have access to MMIO.
2639	  See also
2640	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2641
2642config MITIGATION_L1TF
2643	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2644	depends on CPU_SUP_INTEL
2645	default y
2646	help
2647	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2648	  hardware vulnerability which allows unprivileged speculative access to data
2649	  available in the Level 1 Data Cache.
2650	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2651
2652config MITIGATION_RETBLEED
2653	bool "Mitigate RETBleed hardware bug"
2654	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2655	default y
2656	help
2657	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2658	  with Return Instructions) vulnerability.  RETBleed is a speculative
2659	  execution attack which takes advantage of microarchitectural behavior
2660	  in many modern microprocessors, similar to Spectre v2. An
2661	  unprivileged attacker can use these flaws to bypass conventional
2662	  memory security restrictions to gain read access to privileged memory
2663	  that would otherwise be inaccessible.
2664
2665config MITIGATION_SPECTRE_V1
2666	bool "Mitigate SPECTRE V1 hardware bug"
2667	default y
2668	help
2669	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2670	  class of side channel attacks that takes advantage of speculative
2671	  execution that bypasses conditional branch instructions used for
2672	  memory access bounds check.
2673	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2674
2675config MITIGATION_SPECTRE_V2
2676	bool "Mitigate SPECTRE V2 hardware bug"
2677	default y
2678	help
2679	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2680	  V2 is a class of side channel attacks that takes advantage of
2681	  indirect branch predictors inside the processor. In Spectre variant 2
2682	  attacks, the attacker can steer speculative indirect branches in the
2683	  victim to gadget code by poisoning the branch target buffer of a CPU
2684	  used for predicting indirect branch addresses.
2685	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2686
2687config MITIGATION_SRBDS
2688	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2689	depends on CPU_SUP_INTEL
2690	default y
2691	help
2692	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2693	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2694	  Sampling (MDS) techniques to infer values returned from special
2695	  register accesses. An unprivileged user can extract values returned
2696	  from RDRAND and RDSEED executed on another core or sibling thread
2697	  using MDS techniques.
2698	  See also
2699	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2700
2701config MITIGATION_SSB
2702	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2703	default y
2704	help
2705	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2706	  hardware security vulnerability and its exploitation takes advantage
2707	  of speculative execution in a similar way to the Meltdown and Spectre
2708	  security vulnerabilities.
2709
2710endif
2711
2712config ARCH_HAS_ADD_PAGES
2713	def_bool y
2714	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2715
2716menu "Power management and ACPI options"
2717
2718config ARCH_HIBERNATION_HEADER
2719	def_bool y
2720	depends on HIBERNATION
2721
2722source "kernel/power/Kconfig"
2723
2724source "drivers/acpi/Kconfig"
2725
2726config X86_APM_BOOT
2727	def_bool y
2728	depends on APM
2729
2730menuconfig APM
2731	tristate "APM (Advanced Power Management) BIOS support"
2732	depends on X86_32 && PM_SLEEP
2733	help
2734	  APM is a BIOS specification for saving power using several different
2735	  techniques. This is mostly useful for battery powered laptops with
2736	  APM compliant BIOSes. If you say Y here, the system time will be
2737	  reset after a RESUME operation, the /proc/apm device will provide
2738	  battery status information, and user-space programs will receive
2739	  notification of APM "events" (e.g. battery status change).
2740
2741	  If you select "Y" here, you can disable actual use of the APM
2742	  BIOS by passing the "apm=off" option to the kernel at boot time.
2743
2744	  Note that the APM support is almost completely disabled for
2745	  machines with more than one CPU.
2746
2747	  In order to use APM, you will need supporting software. For location
2748	  and more information, read <file:Documentation/power/apm-acpi.rst>
2749	  and the Battery Powered Linux mini-HOWTO, available from
2750	  <http://www.tldp.org/docs.html#howto>.
2751
2752	  This driver does not spin down disk drives (see the hdparm(8)
2753	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2754	  VESA-compliant "green" monitors.
2755
2756	  This driver does not support the TI 4000M TravelMate and the ACER
2757	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2758	  desktop machines also don't have compliant BIOSes, and this driver
2759	  may cause those machines to panic during the boot phase.
2760
2761	  Generally, if you don't have a battery in your machine, there isn't
2762	  much point in using this driver and you should say N. If you get
2763	  random kernel OOPSes or reboots that don't seem to be related to
2764	  anything, try disabling/enabling this option (or disabling/enabling
2765	  APM in your BIOS).
2766
2767	  Some other things you should try when experiencing seemingly random,
2768	  "weird" problems:
2769
2770	  1) make sure that you have enough swap space and that it is
2771	  enabled.
2772	  2) pass the "idle=poll" option to the kernel
2773	  3) switch on floating point emulation in the kernel and pass
2774	  the "no387" option to the kernel
2775	  4) pass the "floppy=nodma" option to the kernel
2776	  5) pass the "mem=4M" option to the kernel (thereby disabling
2777	  all but the first 4 MB of RAM)
2778	  6) make sure that the CPU is not over clocked.
2779	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2780	  8) disable the cache from your BIOS settings
2781	  9) install a fan for the video card or exchange video RAM
2782	  10) install a better fan for the CPU
2783	  11) exchange RAM chips
2784	  12) exchange the motherboard.
2785
2786	  To compile this driver as a module, choose M here: the
2787	  module will be called apm.
2788
2789if APM
2790
2791config APM_IGNORE_USER_SUSPEND
2792	bool "Ignore USER SUSPEND"
2793	help
2794	  This option will ignore USER SUSPEND requests. On machines with a
2795	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2796	  series notebooks, it is necessary to say Y because of a BIOS bug.
2797
2798config APM_DO_ENABLE
2799	bool "Enable PM at boot time"
2800	help
2801	  Enable APM features at boot time. From page 36 of the APM BIOS
2802	  specification: "When disabled, the APM BIOS does not automatically
2803	  power manage devices, enter the Standby State, enter the Suspend
2804	  State, or take power saving steps in response to CPU Idle calls."
2805	  This driver will make CPU Idle calls when Linux is idle (unless this
2806	  feature is turned off -- see "Do CPU IDLE calls", below). This
2807	  should always save battery power, but more complicated APM features
2808	  will be dependent on your BIOS implementation. You may need to turn
2809	  this option off if your computer hangs at boot time when using APM
2810	  support, or if it beeps continuously instead of suspending. Turn
2811	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2812	  T400CDT. This is off by default since most machines do fine without
2813	  this feature.
2814
2815config APM_CPU_IDLE
2816	depends on CPU_IDLE
2817	bool "Make CPU Idle calls when idle"
2818	help
2819	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2820	  On some machines, this can activate improved power savings, such as
2821	  a slowed CPU clock rate, when the machine is idle. These idle calls
2822	  are made after the idle loop has run for some length of time (e.g.,
2823	  333 mS). On some machines, this will cause a hang at boot time or
2824	  whenever the CPU becomes idle. (On machines with more than one CPU,
2825	  this option does nothing.)
2826
2827config APM_DISPLAY_BLANK
2828	bool "Enable console blanking using APM"
2829	help
2830	  Enable console blanking using the APM. Some laptops can use this to
2831	  turn off the LCD backlight when the screen blanker of the Linux
2832	  virtual console blanks the screen. Note that this is only used by
2833	  the virtual console screen blanker, and won't turn off the backlight
2834	  when using the X Window system. This also doesn't have anything to
2835	  do with your VESA-compliant power-saving monitor. Further, this
2836	  option doesn't work for all laptops -- it might not turn off your
2837	  backlight at all, or it might print a lot of errors to the console,
2838	  especially if you are using gpm.
2839
2840config APM_ALLOW_INTS
2841	bool "Allow interrupts during APM BIOS calls"
2842	help
2843	  Normally we disable external interrupts while we are making calls to
2844	  the APM BIOS as a measure to lessen the effects of a badly behaving
2845	  BIOS implementation.  The BIOS should reenable interrupts if it
2846	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2847	  many of the newer IBM Thinkpads.  If you experience hangs when you
2848	  suspend, try setting this to Y.  Otherwise, say N.
2849
2850endif # APM
2851
2852source "drivers/cpufreq/Kconfig"
2853
2854source "drivers/cpuidle/Kconfig"
2855
2856source "drivers/idle/Kconfig"
2857
2858endmenu
2859
2860menu "Bus options (PCI etc.)"
2861
2862choice
2863	prompt "PCI access mode"
2864	depends on X86_32 && PCI
2865	default PCI_GOANY
2866	help
2867	  On PCI systems, the BIOS can be used to detect the PCI devices and
2868	  determine their configuration. However, some old PCI motherboards
2869	  have BIOS bugs and may crash if this is done. Also, some embedded
2870	  PCI-based systems don't have any BIOS at all. Linux can also try to
2871	  detect the PCI hardware directly without using the BIOS.
2872
2873	  With this option, you can specify how Linux should detect the
2874	  PCI devices. If you choose "BIOS", the BIOS will be used,
2875	  if you choose "Direct", the BIOS won't be used, and if you
2876	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2877	  If you choose "Any", the kernel will try MMCONFIG, then the
2878	  direct access method and falls back to the BIOS if that doesn't
2879	  work. If unsure, go with the default, which is "Any".
2880
2881config PCI_GOBIOS
2882	bool "BIOS"
2883
2884config PCI_GOMMCONFIG
2885	bool "MMConfig"
2886
2887config PCI_GODIRECT
2888	bool "Direct"
2889
2890config PCI_GOOLPC
2891	bool "OLPC XO-1"
2892	depends on OLPC
2893
2894config PCI_GOANY
2895	bool "Any"
2896
2897endchoice
2898
2899config PCI_BIOS
2900	def_bool y
2901	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2902
2903# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2904config PCI_DIRECT
2905	def_bool y
2906	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2907
2908config PCI_MMCONFIG
2909	bool "Support mmconfig PCI config space access" if X86_64
2910	default y
2911	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2912	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2913	help
2914	  Add support for accessing the PCI configuration space as a memory
2915	  mapped area. It is the recommended method if the system supports
2916	  this (it must have PCI Express and ACPI for it to be available).
2917
2918	  In the unlikely case that enabling this configuration option causes
2919	  problems, the mechanism can be switched off with the 'pci=nommconf'
2920	  command line parameter.
2921
2922	  Say N only if you are sure that your platform does not support this
2923	  access method or you have problems caused by it.
2924
2925	  Say Y otherwise.
2926
2927config PCI_OLPC
2928	def_bool y
2929	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2930
2931config PCI_XEN
2932	def_bool y
2933	depends on PCI && XEN
2934
2935config MMCONF_FAM10H
2936	def_bool y
2937	depends on X86_64 && PCI_MMCONFIG && ACPI
2938
2939config PCI_CNB20LE_QUIRK
2940	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2941	depends on X86_32 && PCI
2942	help
2943	  Read the PCI windows out of the CNB20LE host bridge. This allows
2944	  PCI hotplug to work on systems with the CNB20LE chipset which do
2945	  not have ACPI.
2946
2947	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2948	  most probably only for Pentium III.
2949
2950	  To find out if you have such a chipset, search for a PCI device with
2951	  1166:0009 PCI IDs, for example by executing
2952		lspci -nn | grep '1166:0009'
2953	  The code is inactive if there is none.
2954
2955	  There's no public spec for this chipset, and this functionality
2956	  is known to be incomplete.
2957
2958	  You should say N unless you know you need this.
2959
2960config ISA_BUS
2961	bool "ISA bus support on modern systems" if EXPERT
2962	help
2963	  Expose ISA bus device drivers and options available for selection and
2964	  configuration. Enable this option if your target machine has an ISA
2965	  bus. ISA is an older system, displaced by PCI and newer bus
2966	  architectures -- if your target machine is modern, it probably does
2967	  not have an ISA bus.
2968
2969	  If unsure, say N.
2970
2971# x86_64 have no ISA slots, but can have ISA-style DMA.
2972config ISA_DMA_API
2973	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2974	default y
2975	help
2976	  Enables ISA-style DMA support for devices requiring such controllers.
2977	  If unsure, say Y.
2978
2979if X86_32
2980
2981config ISA
2982	bool "ISA support"
2983	help
2984	  Find out whether you have ISA slots on your motherboard.  ISA is the
2985	  name of a bus system, i.e. the way the CPU talks to the other stuff
2986	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2987	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2988	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2989
2990config SCx200
2991	tristate "NatSemi SCx200 support"
2992	help
2993	  This provides basic support for National Semiconductor's
2994	  (now AMD's) Geode processors.  The driver probes for the
2995	  PCI-IDs of several on-chip devices, so its a good dependency
2996	  for other scx200_* drivers.
2997
2998	  If compiled as a module, the driver is named scx200.
2999
3000config SCx200HR_TIMER
3001	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
3002	depends on SCx200
3003	default y
3004	help
3005	  This driver provides a clocksource built upon the on-chip
3006	  27MHz high-resolution timer.  Its also a workaround for
3007	  NSC Geode SC-1100's buggy TSC, which loses time when the
3008	  processor goes idle (as is done by the scheduler).  The
3009	  other workaround is idle=poll boot option.
3010
3011config OLPC
3012	bool "One Laptop Per Child support"
3013	depends on !X86_PAE
3014	select GPIOLIB
3015	select OF
3016	select OF_PROMTREE
3017	select IRQ_DOMAIN
3018	select OLPC_EC
3019	help
3020	  Add support for detecting the unique features of the OLPC
3021	  XO hardware.
3022
3023config OLPC_XO1_PM
3024	bool "OLPC XO-1 Power Management"
3025	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3026	help
3027	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3028
3029config OLPC_XO1_RTC
3030	bool "OLPC XO-1 Real Time Clock"
3031	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3032	help
3033	  Add support for the XO-1 real time clock, which can be used as a
3034	  programmable wakeup source.
3035
3036config OLPC_XO1_SCI
3037	bool "OLPC XO-1 SCI extras"
3038	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3039	depends on INPUT=y
3040	select POWER_SUPPLY
3041	help
3042	  Add support for SCI-based features of the OLPC XO-1 laptop:
3043	   - EC-driven system wakeups
3044	   - Power button
3045	   - Ebook switch
3046	   - Lid switch
3047	   - AC adapter status updates
3048	   - Battery status updates
3049
3050config OLPC_XO15_SCI
3051	bool "OLPC XO-1.5 SCI extras"
3052	depends on OLPC && ACPI
3053	select POWER_SUPPLY
3054	help
3055	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3056	   - EC-driven system wakeups
3057	   - AC adapter status updates
3058	   - Battery status updates
3059
3060config GEODE_COMMON
3061	bool
3062
3063config ALIX
3064	bool "PCEngines ALIX System Support (LED setup)"
3065	select GPIOLIB
3066	select GEODE_COMMON
3067	help
3068	  This option enables system support for the PCEngines ALIX.
3069	  At present this just sets up LEDs for GPIO control on
3070	  ALIX2/3/6 boards.  However, other system specific setup should
3071	  get added here.
3072
3073	  Note: You must still enable the drivers for GPIO and LED support
3074	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3075
3076	  Note: You have to set alix.force=1 for boards with Award BIOS.
3077
3078config NET5501
3079	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3080	select GPIOLIB
3081	select GEODE_COMMON
3082	help
3083	  This option enables system support for the Soekris Engineering net5501.
3084
3085config GEOS
3086	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3087	select GPIOLIB
3088	select GEODE_COMMON
3089	depends on DMI
3090	help
3091	  This option enables system support for the Traverse Technologies GEOS.
3092
3093config TS5500
3094	bool "Technologic Systems TS-5500 platform support"
3095	depends on MELAN
3096	select CHECK_SIGNATURE
3097	select NEW_LEDS
3098	select LEDS_CLASS
3099	help
3100	  This option enables system support for the Technologic Systems TS-5500.
3101
3102endif # X86_32
3103
3104config AMD_NB
3105	def_bool y
3106	depends on AMD_NODE
3107
3108config AMD_NODE
3109	def_bool y
3110	depends on CPU_SUP_AMD && PCI
3111
3112endmenu
3113
3114menu "Binary Emulations"
3115
3116config IA32_EMULATION
3117	bool "IA32 Emulation"
3118	depends on X86_64
3119	select ARCH_WANT_OLD_COMPAT_IPC
3120	select BINFMT_ELF
3121	select COMPAT_OLD_SIGACTION
3122	help
3123	  Include code to run legacy 32-bit programs under a
3124	  64-bit kernel. You should likely turn this on, unless you're
3125	  100% sure that you don't have any 32-bit programs left.
3126
3127config IA32_EMULATION_DEFAULT_DISABLED
3128	bool "IA32 emulation disabled by default"
3129	default n
3130	depends on IA32_EMULATION
3131	help
3132	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3133	  processes and access to 32-bit syscalls. If unsure, leave it to its
3134	  default value.
3135
3136config X86_X32_ABI
3137	bool "x32 ABI for 64-bit mode"
3138	depends on X86_64
3139	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3140	# compressed debug sections to x86_x32 properly:
3141	# https://github.com/ClangBuiltLinux/linux/issues/514
3142	# https://github.com/ClangBuiltLinux/linux/issues/1141
3143	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3144	help
3145	  Include code to run binaries for the x32 native 32-bit ABI
3146	  for 64-bit processors.  An x32 process gets access to the
3147	  full 64-bit register file and wide data path while leaving
3148	  pointers at 32 bits for smaller memory footprint.
3149
3150config COMPAT_32
3151	def_bool y
3152	depends on IA32_EMULATION || X86_32
3153	select HAVE_UID16
3154	select OLD_SIGSUSPEND3
3155
3156config COMPAT
3157	def_bool y
3158	depends on IA32_EMULATION || X86_X32_ABI
3159
3160config COMPAT_FOR_U64_ALIGNMENT
3161	def_bool y
3162	depends on COMPAT
3163
3164endmenu
3165
3166config HAVE_ATOMIC_IOMAP
3167	def_bool y
3168	depends on X86_32
3169
3170source "arch/x86/kvm/Kconfig"
3171
3172source "arch/x86/Kconfig.cpufeatures"
3173
3174source "arch/x86/Kconfig.assembler"
3175