xref: /linux/arch/x86/Kconfig (revision beb69e81724634063b9dbae4bc79e2e011fdeeb1)
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_MSEAL_SYSTEM_MAPPINGS
31	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
32	select ARCH_SUPPORTS_PER_VMA_LOCK
33	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
34	select HAVE_ARCH_SOFT_DIRTY
35	select MODULES_USE_ELF_RELA
36	select NEED_DMA_MAP_STATE
37	select SWIOTLB
38	select ARCH_HAS_ELFCORE_COMPAT
39	select ZONE_DMA32
40	select EXECMEM if DYNAMIC_FTRACE
41	select ACPI_MRRM if ACPI
42
43config FORCE_DYNAMIC_FTRACE
44	def_bool y
45	depends on X86_32
46	depends on FUNCTION_TRACER
47	select DYNAMIC_FTRACE
48	help
49	  We keep the static function tracing (!DYNAMIC_FTRACE) around
50	  in order to test the non static function tracing in the
51	  generic code, as other architectures still use it. But we
52	  only need to keep it around for x86_64. No need to keep it
53	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
54#
55# Arch settings
56#
57# ( Note that options that are marked 'if X86_64' could in principle be
58#   ported to 32-bit as well. )
59#
60config X86
61	def_bool y
62	#
63	# Note: keep this list sorted alphabetically
64	#
65	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
66	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
67	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
68	select ARCH_32BIT_OFF_T			if X86_32
69	select ARCH_CLOCKSOURCE_INIT
70	select ARCH_CONFIGURES_CPU_MITIGATIONS
71	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
72	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
73	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
74	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
75	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
76	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
77	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
78	select ARCH_HAS_CACHE_LINE_SIZE
79	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
80	select ARCH_HAS_CPU_FINALIZE_INIT
81	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
82	select ARCH_HAS_CRC32
83	select ARCH_HAS_CRC64			if X86_64
84	select ARCH_HAS_CRC_T10DIF
85	select ARCH_HAS_CURRENT_STACK_POINTER
86	select ARCH_HAS_DEBUG_VIRTUAL
87	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
88	select ARCH_HAS_DEVMEM_IS_ALLOWED
89	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
90	select ARCH_HAS_EARLY_DEBUG		if KGDB
91	select ARCH_HAS_ELF_RANDOMIZE
92	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
93	select ARCH_HAS_FAST_MULTIPLIER
94	select ARCH_HAS_FORTIFY_SOURCE
95	select ARCH_HAS_GCOV_PROFILE_ALL
96	select ARCH_HAS_KCOV			if X86_64
97	select ARCH_HAS_KERNEL_FPU_SUPPORT
98	select ARCH_HAS_MEM_ENCRYPT
99	select ARCH_HAS_MEMBARRIER_SYNC_CORE
100	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
101	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
102	select ARCH_HAS_PMEM_API		if X86_64
103	select ARCH_HAS_PREEMPT_LAZY
104	select ARCH_HAS_PTE_SPECIAL
105	select ARCH_HAS_HW_PTE_YOUNG
106	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
107	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
108	select ARCH_HAS_COPY_MC			if X86_64
109	select ARCH_HAS_SET_MEMORY
110	select ARCH_HAS_SET_DIRECT_MAP
111	select ARCH_HAS_STRICT_KERNEL_RWX
112	select ARCH_HAS_STRICT_MODULE_RWX
113	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
114	select ARCH_HAS_SYSCALL_WRAPPER
115	select ARCH_HAS_UBSAN
116	select ARCH_HAS_DEBUG_WX
117	select ARCH_HAS_ZONE_DMA_SET if EXPERT
118	select ARCH_HAVE_NMI_SAFE_CMPXCHG
119	select ARCH_HAVE_EXTRA_ELF_NOTES
120	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
121	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
122	select ARCH_MIGHT_HAVE_PC_PARPORT
123	select ARCH_MIGHT_HAVE_PC_SERIO
124	select ARCH_STACKWALK
125	select ARCH_SUPPORTS_ACPI
126	select ARCH_SUPPORTS_ATOMIC_RMW
127	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
128	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
129	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
130	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
131	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
132	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
133	select ARCH_SUPPORTS_LTO_CLANG
134	select ARCH_SUPPORTS_LTO_CLANG_THIN
135	select ARCH_SUPPORTS_RT
136	select ARCH_SUPPORTS_AUTOFDO_CLANG
137	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
138	select ARCH_USE_BUILTIN_BSWAP
139	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CX8
140	select ARCH_USE_MEMTEST
141	select ARCH_USE_QUEUED_RWLOCKS
142	select ARCH_USE_QUEUED_SPINLOCKS
143	select ARCH_USE_SYM_ANNOTATIONS
144	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
145	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
146	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
147	select ARCH_WANTS_NO_INSTR
148	select ARCH_WANT_GENERAL_HUGETLB
149	select ARCH_WANT_HUGE_PMD_SHARE
150	select ARCH_WANT_LD_ORPHAN_WARN
151	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
152	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
153	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
154	select ARCH_WANTS_THP_SWAP		if X86_64
155	select ARCH_HAS_PARANOID_L1D_FLUSH
156	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
157	select BUILDTIME_TABLE_SORT
158	select CLKEVT_I8253
159	select CLOCKSOURCE_WATCHDOG
160	# Word-size accesses may read uninitialized data past the trailing \0
161	# in strings and cause false KMSAN reports.
162	select DCACHE_WORD_ACCESS		if !KMSAN
163	select DYNAMIC_SIGFRAME
164	select EDAC_ATOMIC_SCRUB
165	select EDAC_SUPPORT
166	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
167	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
168	select GENERIC_CLOCKEVENTS_MIN_ADJUST
169	select GENERIC_CMOS_UPDATE
170	select GENERIC_CPU_AUTOPROBE
171	select GENERIC_CPU_DEVICES
172	select GENERIC_CPU_VULNERABILITIES
173	select GENERIC_EARLY_IOREMAP
174	select GENERIC_ENTRY
175	select GENERIC_IOMAP
176	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
177	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
178	select GENERIC_IRQ_MIGRATION		if SMP
179	select GENERIC_IRQ_PROBE
180	select GENERIC_IRQ_RESERVATION_MODE
181	select GENERIC_IRQ_SHOW
182	select GENERIC_PENDING_IRQ		if SMP
183	select GENERIC_SMP_IDLE_THREAD
184	select GENERIC_TIME_VSYSCALL
185	select GENERIC_GETTIMEOFDAY
186	select GENERIC_VDSO_DATA_STORE
187	select GENERIC_VDSO_TIME_NS
188	select GENERIC_VDSO_OVERFLOW_PROTECT
189	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
190	select HARDIRQS_SW_RESEND
191	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
192	select HAS_IOPORT
193	select HAVE_ACPI_APEI			if ACPI
194	select HAVE_ACPI_APEI_NMI		if ACPI
195	select HAVE_ALIGNED_STRUCT_PAGE
196	select HAVE_ARCH_AUDITSYSCALL
197	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
198	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
199	select HAVE_ARCH_JUMP_LABEL
200	select HAVE_ARCH_JUMP_LABEL_RELATIVE
201	select HAVE_ARCH_KASAN			if X86_64
202	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
203	select HAVE_ARCH_KFENCE
204	select HAVE_ARCH_KMSAN			if X86_64
205	select HAVE_ARCH_KGDB
206	select HAVE_ARCH_MMAP_RND_BITS		if MMU
207	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
208	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
209	select HAVE_ARCH_PREL32_RELOCATIONS
210	select HAVE_ARCH_SECCOMP_FILTER
211	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
212	select HAVE_ARCH_STACKLEAK
213	select HAVE_ARCH_TRACEHOOK
214	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
215	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
216	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
217	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
218	select HAVE_ARCH_VMAP_STACK		if X86_64
219	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
220	select HAVE_ARCH_WITHIN_STACK_FRAMES
221	select HAVE_ASM_MODVERSIONS
222	select HAVE_CMPXCHG_DOUBLE
223	select HAVE_CMPXCHG_LOCAL
224	select HAVE_CONTEXT_TRACKING_USER		if X86_64
225	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
226	select HAVE_C_RECORDMCOUNT
227	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
228	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
229	select HAVE_BUILDTIME_MCOUNT_SORT
230	select HAVE_DEBUG_KMEMLEAK
231	select HAVE_DMA_CONTIGUOUS
232	select HAVE_DYNAMIC_FTRACE
233	select HAVE_DYNAMIC_FTRACE_WITH_REGS
234	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
235	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
236	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
237	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
238	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
239	select HAVE_EBPF_JIT
240	select HAVE_EFFICIENT_UNALIGNED_ACCESS
241	select HAVE_EISA			if X86_32
242	select HAVE_EXIT_THREAD
243	select HAVE_GUP_FAST
244	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
245	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
246	select HAVE_FTRACE_MCOUNT_RECORD
247	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
248	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
249	select HAVE_FUNCTION_TRACER
250	select HAVE_GCC_PLUGINS
251	select HAVE_HW_BREAKPOINT
252	select HAVE_IOREMAP_PROT
253	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
254	select HAVE_IRQ_TIME_ACCOUNTING
255	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
256	select HAVE_KERNEL_BZIP2
257	select HAVE_KERNEL_GZIP
258	select HAVE_KERNEL_LZ4
259	select HAVE_KERNEL_LZMA
260	select HAVE_KERNEL_LZO
261	select HAVE_KERNEL_XZ
262	select HAVE_KERNEL_ZSTD
263	select HAVE_KPROBES
264	select HAVE_KPROBES_ON_FTRACE
265	select HAVE_FUNCTION_ERROR_INJECTION
266	select HAVE_KRETPROBES
267	select HAVE_RETHOOK
268	select HAVE_LIVEPATCH			if X86_64
269	select HAVE_MIXED_BREAKPOINTS_REGS
270	select HAVE_MOD_ARCH_SPECIFIC
271	select HAVE_MOVE_PMD
272	select HAVE_MOVE_PUD
273	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
274	select HAVE_NMI
275	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
276	select HAVE_OBJTOOL			if X86_64
277	select HAVE_OPTPROBES
278	select HAVE_PAGE_SIZE_4KB
279	select HAVE_PCSPKR_PLATFORM
280	select HAVE_PERF_EVENTS
281	select HAVE_PERF_EVENTS_NMI
282	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
283	select HAVE_PCI
284	select HAVE_PERF_REGS
285	select HAVE_PERF_USER_STACK_DUMP
286	select MMU_GATHER_RCU_TABLE_FREE
287	select MMU_GATHER_MERGE_VMAS
288	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
289	select HAVE_REGS_AND_STACK_ACCESS_API
290	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
291	select HAVE_FUNCTION_ARG_ACCESS_API
292	select HAVE_SETUP_PER_CPU_AREA
293	select HAVE_SOFTIRQ_ON_OWN_STACK
294	select HAVE_STACKPROTECTOR
295	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
296	select HAVE_STATIC_CALL
297	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
298	select HAVE_PREEMPT_DYNAMIC_CALL
299	select HAVE_RSEQ
300	select HAVE_RUST			if X86_64
301	select HAVE_SYSCALL_TRACEPOINTS
302	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
303	select HAVE_UNSTABLE_SCHED_CLOCK
304	select HAVE_USER_RETURN_NOTIFIER
305	select HAVE_GENERIC_VDSO
306	select VDSO_GETRANDOM			if X86_64
307	select HOTPLUG_PARALLEL			if SMP && X86_64
308	select HOTPLUG_SMT			if SMP
309	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
310	select IRQ_FORCED_THREADING
311	select LOCK_MM_AND_FIND_VMA
312	select NEED_PER_CPU_EMBED_FIRST_CHUNK
313	select NEED_PER_CPU_PAGE_FIRST_CHUNK
314	select NEED_SG_DMA_LENGTH
315	select NUMA_MEMBLKS			if NUMA
316	select PCI_DOMAINS			if PCI
317	select PCI_LOCKLESS_CONFIG		if PCI
318	select PERF_EVENTS
319	select RTC_LIB
320	select RTC_MC146818_LIB
321	select SPARSE_IRQ
322	select SYSCTL_EXCEPTION_TRACE
323	select THREAD_INFO_IN_TASK
324	select TRACE_IRQFLAGS_SUPPORT
325	select TRACE_IRQFLAGS_NMI_SUPPORT
326	select USER_STACKTRACE_SUPPORT
327	select HAVE_ARCH_KCSAN			if X86_64
328	select PROC_PID_ARCH_STATUS		if PROC_FS
329	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
330	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
331	select FUNCTION_ALIGNMENT_4B
332	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
333	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
334	select ARCH_SUPPORTS_PT_RECLAIM		if X86_64
335
336config INSTRUCTION_DECODER
337	def_bool y
338	depends on KPROBES || PERF_EVENTS || UPROBES
339
340config OUTPUT_FORMAT
341	string
342	default "elf32-i386" if X86_32
343	default "elf64-x86-64" if X86_64
344
345config LOCKDEP_SUPPORT
346	def_bool y
347
348config STACKTRACE_SUPPORT
349	def_bool y
350
351config MMU
352	def_bool y
353
354config ARCH_MMAP_RND_BITS_MIN
355	default 28 if 64BIT
356	default 8
357
358config ARCH_MMAP_RND_BITS_MAX
359	default 32 if 64BIT
360	default 16
361
362config ARCH_MMAP_RND_COMPAT_BITS_MIN
363	default 8
364
365config ARCH_MMAP_RND_COMPAT_BITS_MAX
366	default 16
367
368config SBUS
369	bool
370
371config GENERIC_ISA_DMA
372	def_bool y
373	depends on ISA_DMA_API
374
375config GENERIC_CSUM
376	bool
377	default y if KMSAN || KASAN
378
379config GENERIC_BUG
380	def_bool y
381	depends on BUG
382	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
383
384config GENERIC_BUG_RELATIVE_POINTERS
385	bool
386
387config ARCH_MAY_HAVE_PC_FDC
388	def_bool y
389	depends on ISA_DMA_API
390
391config GENERIC_CALIBRATE_DELAY
392	def_bool y
393
394config ARCH_HAS_CPU_RELAX
395	def_bool y
396
397config ARCH_HIBERNATION_POSSIBLE
398	def_bool y
399
400config ARCH_SUSPEND_POSSIBLE
401	def_bool y
402
403config AUDIT_ARCH
404	def_bool y if X86_64
405
406config KASAN_SHADOW_OFFSET
407	hex
408	depends on KASAN
409	default 0xdffffc0000000000
410
411config HAVE_INTEL_TXT
412	def_bool y
413	depends on INTEL_IOMMU && ACPI
414
415config X86_64_SMP
416	def_bool y
417	depends on X86_64 && SMP
418
419config ARCH_SUPPORTS_UPROBES
420	def_bool y
421
422config FIX_EARLYCON_MEM
423	def_bool y
424
425config DYNAMIC_PHYSICAL_MASK
426	bool
427
428config PGTABLE_LEVELS
429	int
430	default 5 if X86_64
431	default 3 if X86_PAE
432	default 2
433
434menu "Processor type and features"
435
436config SMP
437	bool "Symmetric multi-processing support"
438	help
439	  This enables support for systems with more than one CPU. If you have
440	  a system with only one CPU, say N. If you have a system with more
441	  than one CPU, say Y.
442
443	  If you say N here, the kernel will run on uni- and multiprocessor
444	  machines, but will use only one CPU of a multiprocessor machine. If
445	  you say Y here, the kernel will run on many, but not all,
446	  uniprocessor machines. On a uniprocessor machine, the kernel
447	  will run faster if you say N here.
448
449	  Note that if you say Y here and choose architecture "586" or
450	  "Pentium" under "Processor family", the kernel will not work on 486
451	  architectures. Similarly, multiprocessor kernels for the "PPro"
452	  architecture may not work on all Pentium based boards.
453
454	  People using multiprocessor machines who say Y here should also say
455	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
456	  Management" code will be disabled if you say Y here.
457
458	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
459	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
460	  <http://www.tldp.org/docs.html#howto>.
461
462	  If you don't know what to do here, say N.
463
464config X86_X2APIC
465	bool "x2APIC interrupt controller architecture support"
466	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
467	default y
468	help
469	  x2APIC is an interrupt controller architecture, a component of which
470	  (the local APIC) is present in the CPU. It allows faster access to
471	  the local APIC and supports a larger number of CPUs in the system
472	  than the predecessors.
473
474	  x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs
475	  in 2019, but it can be disabled by the BIOS. It is also frequently
476	  emulated in virtual machines, even when the host CPU does not support
477	  it. Support in the CPU can be checked by executing
478		grep x2apic /proc/cpuinfo
479
480	  If this configuration option is disabled, the kernel will boot with
481	  very reduced functionality and performance on some platforms that
482	  have x2APIC enabled. On the other hand, on hardware that does not
483	  support x2APIC, a kernel with this option enabled will just fallback
484	  to older APIC implementations.
485
486	  If in doubt, say Y.
487
488config X86_POSTED_MSI
489	bool "Enable MSI and MSI-x delivery by posted interrupts"
490	depends on X86_64 && IRQ_REMAP
491	help
492	  This enables MSIs that are under interrupt remapping to be delivered as
493	  posted interrupts to the host kernel. Interrupt throughput can
494	  potentially be improved by coalescing CPU notifications during high
495	  frequency bursts.
496
497	  If you don't know what to do here, say N.
498
499config X86_MPPARSE
500	bool "Enable MPS table" if ACPI
501	default y
502	depends on X86_LOCAL_APIC
503	help
504	  For old smp systems that do not have proper acpi support. Newer systems
505	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
506
507config X86_CPU_RESCTRL
508	bool "x86 CPU resource control support"
509	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
510	depends on MISC_FILESYSTEMS
511	select ARCH_HAS_CPU_RESCTRL
512	select RESCTRL_FS
513	select RESCTRL_FS_PSEUDO_LOCK
514	help
515	  Enable x86 CPU resource control support.
516
517	  Provide support for the allocation and monitoring of system resources
518	  usage by the CPU.
519
520	  Intel calls this Intel Resource Director Technology
521	  (Intel(R) RDT). More information about RDT can be found in the
522	  Intel x86 Architecture Software Developer Manual.
523
524	  AMD calls this AMD Platform Quality of Service (AMD QoS).
525	  More information about AMD QoS can be found in the AMD64 Technology
526	  Platform Quality of Service Extensions manual.
527
528	  Say N if unsure.
529
530config X86_FRED
531	bool "Flexible Return and Event Delivery"
532	depends on X86_64
533	help
534	  When enabled, try to use Flexible Return and Event Delivery
535	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
536	  ring transitions and exception/interrupt handling if the
537	  system supports it.
538
539config X86_EXTENDED_PLATFORM
540	bool "Support for extended (non-PC) x86 platforms"
541	default y
542	help
543	  If you disable this option then the kernel will only support
544	  standard PC platforms. (which covers the vast majority of
545	  systems out there.)
546
547	  If you enable this option then you'll be able to select support
548	  for the following non-PC x86 platforms, depending on the value of
549	  CONFIG_64BIT.
550
551	  32-bit platforms (CONFIG_64BIT=n):
552		Goldfish (mostly Android emulator)
553		Intel CE media processor (CE4100) SoC
554		Intel Quark
555		RDC R-321x SoC
556
557	  64-bit platforms (CONFIG_64BIT=y):
558		Numascale NumaChip
559		ScaleMP vSMP
560		SGI Ultraviolet
561		Merrifield/Moorefield MID devices
562		Goldfish (mostly Android emulator)
563
564	  If you have one of these systems, or if you want to build a
565	  generic distribution kernel, say Y here - otherwise say N.
566
567# This is an alphabetically sorted list of 64 bit extended platforms
568# Please maintain the alphabetic order if and when there are additions
569config X86_NUMACHIP
570	bool "Numascale NumaChip"
571	depends on X86_64
572	depends on X86_EXTENDED_PLATFORM
573	depends on NUMA
574	depends on SMP
575	depends on X86_X2APIC
576	depends on PCI_MMCONFIG
577	help
578	  Adds support for Numascale NumaChip large-SMP systems. Needed to
579	  enable more than ~168 cores.
580	  If you don't have one of these, you should say N here.
581
582config X86_VSMP
583	bool "ScaleMP vSMP"
584	select HYPERVISOR_GUEST
585	select PARAVIRT
586	depends on X86_64 && PCI
587	depends on X86_EXTENDED_PLATFORM
588	depends on SMP
589	help
590	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
591	  supposed to run on these EM64T-based machines.  Only choose this option
592	  if you have one of these machines.
593
594config X86_UV
595	bool "SGI Ultraviolet"
596	depends on X86_64
597	depends on X86_EXTENDED_PLATFORM
598	depends on NUMA
599	depends on EFI
600	depends on KEXEC_CORE
601	depends on X86_X2APIC
602	depends on PCI
603	help
604	  This option is needed in order to support SGI Ultraviolet systems.
605	  If you don't have one of these, you should say N here.
606
607config X86_INTEL_MID
608	bool "Intel Z34xx/Z35xx MID platform support"
609	depends on X86_EXTENDED_PLATFORM
610	depends on X86_PLATFORM_DEVICES
611	depends on PCI
612	depends on X86_64 || (EXPERT && PCI_GOANY)
613	depends on X86_IO_APIC
614	select I2C
615	select DW_APB_TIMER
616	select INTEL_SCU_PCI
617	help
618	  Select to build a kernel capable of supporting 64-bit Intel MID
619	  (Mobile Internet Device) platform systems which do not have
620	  the PCI legacy interfaces.
621
622	  The only supported devices are the 22nm Merrified (Z34xx)
623	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
624	  a small number of Android devices such as the Asus Zenfone 2,
625	  Asus FonePad 8 and Dell Venue 7.
626
627	  If you are building for a PC class system or non-MID tablet
628	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
629
630	  Intel MID platforms are based on an Intel processor and chipset which
631	  consume less power than most of the x86 derivatives.
632
633config X86_GOLDFISH
634	bool "Goldfish (Virtual Platform)"
635	depends on X86_EXTENDED_PLATFORM
636	help
637	  Enable support for the Goldfish virtual platform used primarily
638	  for Android development. Unless you are building for the Android
639	  Goldfish emulator say N here.
640
641# Following is an alphabetically sorted list of 32 bit extended platforms
642# Please maintain the alphabetic order if and when there are additions
643
644config X86_INTEL_CE
645	bool "CE4100 TV platform"
646	depends on PCI
647	depends on PCI_GODIRECT
648	depends on X86_IO_APIC
649	depends on X86_32
650	depends on X86_EXTENDED_PLATFORM
651	select X86_REBOOTFIXUPS
652	select OF
653	select OF_EARLY_FLATTREE
654	help
655	  Select for the Intel CE media processor (CE4100) SOC.
656	  This option compiles in support for the CE4100 SOC for settop
657	  boxes and media devices.
658
659config X86_INTEL_QUARK
660	bool "Intel Quark platform support"
661	depends on X86_32
662	depends on X86_EXTENDED_PLATFORM
663	depends on X86_PLATFORM_DEVICES
664	depends on X86_TSC
665	depends on PCI
666	depends on PCI_GOANY
667	depends on X86_IO_APIC
668	select IOSF_MBI
669	select INTEL_IMR
670	select COMMON_CLK
671	help
672	  Select to include support for Quark X1000 SoC.
673	  Say Y here if you have a Quark based system such as the Arduino
674	  compatible Intel Galileo.
675
676config X86_RDC321X
677	bool "RDC R-321x SoC"
678	depends on X86_32
679	depends on X86_EXTENDED_PLATFORM
680	select M486
681	select X86_REBOOTFIXUPS
682	help
683	  This option is needed for RDC R-321x system-on-chip, also known
684	  as R-8610-(G).
685	  If you don't have one of these chips, you should say N here.
686
687config X86_INTEL_LPSS
688	bool "Intel Low Power Subsystem Support"
689	depends on X86 && ACPI && PCI
690	select COMMON_CLK
691	select PINCTRL
692	select IOSF_MBI
693	help
694	  Select to build support for Intel Low Power Subsystem such as
695	  found on Intel Lynxpoint PCH. Selecting this option enables
696	  things like clock tree (common clock framework) and pincontrol
697	  which are needed by the LPSS peripheral drivers.
698
699config X86_AMD_PLATFORM_DEVICE
700	bool "AMD ACPI2Platform devices support"
701	depends on ACPI
702	select COMMON_CLK
703	select PINCTRL
704	help
705	  Select to interpret AMD specific ACPI device to platform device
706	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
707	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
708	  implemented under PINCTRL subsystem.
709
710config IOSF_MBI
711	tristate "Intel SoC IOSF Sideband support for SoC platforms"
712	depends on PCI
713	help
714	  This option enables sideband register access support for Intel SoC
715	  platforms. On these platforms the IOSF sideband is used in lieu of
716	  MSR's for some register accesses, mostly but not limited to thermal
717	  and power. Drivers may query the availability of this device to
718	  determine if they need the sideband in order to work on these
719	  platforms. The sideband is available on the following SoC products.
720	  This list is not meant to be exclusive.
721	   - BayTrail
722	   - Braswell
723	   - Quark
724
725	  You should say Y if you are running a kernel on one of these SoC's.
726
727config IOSF_MBI_DEBUG
728	bool "Enable IOSF sideband access through debugfs"
729	depends on IOSF_MBI && DEBUG_FS
730	help
731	  Select this option to expose the IOSF sideband access registers (MCR,
732	  MDR, MCRX) through debugfs to write and read register information from
733	  different units on the SoC. This is most useful for obtaining device
734	  state information for debug and analysis. As this is a general access
735	  mechanism, users of this option would have specific knowledge of the
736	  device they want to access.
737
738	  If you don't require the option or are in doubt, say N.
739
740config X86_SUPPORTS_MEMORY_FAILURE
741	def_bool y
742	# MCE code calls memory_failure():
743	depends on X86_MCE
744	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
745	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
746	depends on X86_64 || !SPARSEMEM
747	select ARCH_SUPPORTS_MEMORY_FAILURE
748
749config X86_32_IRIS
750	tristate "Eurobraille/Iris poweroff module"
751	depends on X86_32
752	help
753	  The Iris machines from EuroBraille do not have APM or ACPI support
754	  to shut themselves down properly.  A special I/O sequence is
755	  needed to do so, which is what this module does at
756	  kernel shutdown.
757
758	  This is only for Iris machines from EuroBraille.
759
760	  If unused, say N.
761
762config SCHED_OMIT_FRAME_POINTER
763	def_bool y
764	prompt "Single-depth WCHAN output"
765	depends on X86
766	help
767	  Calculate simpler /proc/<PID>/wchan values. If this option
768	  is disabled then wchan values will recurse back to the
769	  caller function. This provides more accurate wchan values,
770	  at the expense of slightly more scheduling overhead.
771
772	  If in doubt, say "Y".
773
774menuconfig HYPERVISOR_GUEST
775	bool "Linux guest support"
776	help
777	  Say Y here to enable options for running Linux under various hyper-
778	  visors. This option enables basic hypervisor detection and platform
779	  setup.
780
781	  If you say N, all options in this submenu will be skipped and
782	  disabled, and Linux guest support won't be built in.
783
784if HYPERVISOR_GUEST
785
786config PARAVIRT
787	bool "Enable paravirtualization code"
788	depends on HAVE_STATIC_CALL
789	help
790	  This changes the kernel so it can modify itself when it is run
791	  under a hypervisor, potentially improving performance significantly
792	  over full virtualization.  However, when run without a hypervisor
793	  the kernel is theoretically slower and slightly larger.
794
795config PARAVIRT_XXL
796	bool
797	depends on X86_64
798
799config PARAVIRT_DEBUG
800	bool "paravirt-ops debugging"
801	depends on PARAVIRT && DEBUG_KERNEL
802	help
803	  Enable to debug paravirt_ops internals.  Specifically, BUG if
804	  a paravirt_op is missing when it is called.
805
806config PARAVIRT_SPINLOCKS
807	bool "Paravirtualization layer for spinlocks"
808	depends on PARAVIRT && SMP
809	help
810	  Paravirtualized spinlocks allow a pvops backend to replace the
811	  spinlock implementation with something virtualization-friendly
812	  (for example, block the virtual CPU rather than spinning).
813
814	  It has a minimal impact on native kernels and gives a nice performance
815	  benefit on paravirtualized KVM / Xen kernels.
816
817	  If you are unsure how to answer this question, answer Y.
818
819config X86_HV_CALLBACK_VECTOR
820	def_bool n
821
822source "arch/x86/xen/Kconfig"
823
824config KVM_GUEST
825	bool "KVM Guest support (including kvmclock)"
826	depends on PARAVIRT
827	select PARAVIRT_CLOCK
828	select ARCH_CPUIDLE_HALTPOLL
829	select X86_HV_CALLBACK_VECTOR
830	default y
831	help
832	  This option enables various optimizations for running under the KVM
833	  hypervisor. It includes a paravirtualized clock, so that instead
834	  of relying on a PIT (or probably other) emulation by the
835	  underlying device model, the host provides the guest with
836	  timing infrastructure such as time of day, and system time
837
838config ARCH_CPUIDLE_HALTPOLL
839	def_bool n
840	prompt "Disable host haltpoll when loading haltpoll driver"
841	help
842	  If virtualized under KVM, disable host haltpoll.
843
844config PVH
845	bool "Support for running PVH guests"
846	help
847	  This option enables the PVH entry point for guest virtual machines
848	  as specified in the x86/HVM direct boot ABI.
849
850config PARAVIRT_TIME_ACCOUNTING
851	bool "Paravirtual steal time accounting"
852	depends on PARAVIRT
853	help
854	  Select this option to enable fine granularity task steal time
855	  accounting. Time spent executing other tasks in parallel with
856	  the current vCPU is discounted from the vCPU power. To account for
857	  that, there can be a small performance impact.
858
859	  If in doubt, say N here.
860
861config PARAVIRT_CLOCK
862	bool
863
864config JAILHOUSE_GUEST
865	bool "Jailhouse non-root cell support"
866	depends on X86_64 && PCI
867	select X86_PM_TIMER
868	help
869	  This option allows to run Linux as guest in a Jailhouse non-root
870	  cell. You can leave this option disabled if you only want to start
871	  Jailhouse and run Linux afterwards in the root cell.
872
873config ACRN_GUEST
874	bool "ACRN Guest support"
875	depends on X86_64
876	select X86_HV_CALLBACK_VECTOR
877	help
878	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
879	  a flexible, lightweight reference open-source hypervisor, built with
880	  real-time and safety-criticality in mind. It is built for embedded
881	  IOT with small footprint and real-time features. More details can be
882	  found in https://projectacrn.org/.
883
884config INTEL_TDX_GUEST
885	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
886	depends on X86_64 && CPU_SUP_INTEL
887	depends on X86_X2APIC
888	depends on EFI_STUB
889	depends on PARAVIRT
890	select ARCH_HAS_CC_PLATFORM
891	select X86_MEM_ENCRYPT
892	select X86_MCE
893	select UNACCEPTED_MEMORY
894	help
895	  Support running as a guest under Intel TDX.  Without this support,
896	  the guest kernel can not boot or run under TDX.
897	  TDX includes memory encryption and integrity capabilities
898	  which protect the confidentiality and integrity of guest
899	  memory contents and CPU state. TDX guests are protected from
900	  some attacks from the VMM.
901
902endif # HYPERVISOR_GUEST
903
904source "arch/x86/Kconfig.cpu"
905
906config HPET_TIMER
907	def_bool X86_64
908	prompt "HPET Timer Support" if X86_32
909	help
910	  Use the IA-PC HPET (High Precision Event Timer) to manage
911	  time in preference to the PIT and RTC, if a HPET is
912	  present.
913	  HPET is the next generation timer replacing legacy 8254s.
914	  The HPET provides a stable time base on SMP
915	  systems, unlike the TSC, but it is more expensive to access,
916	  as it is off-chip.  The interface used is documented
917	  in the HPET spec, revision 1.
918
919	  You can safely choose Y here.  However, HPET will only be
920	  activated if the platform and the BIOS support this feature.
921	  Otherwise the 8254 will be used for timing services.
922
923	  Choose N to continue using the legacy 8254 timer.
924
925config HPET_EMULATE_RTC
926	def_bool y
927	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
928
929# Mark as expert because too many people got it wrong.
930# The code disables itself when not needed.
931config DMI
932	default y
933	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
934	bool "Enable DMI scanning" if EXPERT
935	help
936	  Enabled scanning of DMI to identify machine quirks. Say Y
937	  here unless you have verified that your setup is not
938	  affected by entries in the DMI blacklist. Required by PNP
939	  BIOS code.
940
941config GART_IOMMU
942	bool "Old AMD GART IOMMU support"
943	select IOMMU_HELPER
944	select SWIOTLB
945	depends on X86_64 && PCI && AMD_NB
946	help
947	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
948	  GART based hardware IOMMUs.
949
950	  The GART supports full DMA access for devices with 32-bit access
951	  limitations, on systems with more than 3 GB. This is usually needed
952	  for USB, sound, many IDE/SATA chipsets and some other devices.
953
954	  Newer systems typically have a modern AMD IOMMU, supported via
955	  the CONFIG_AMD_IOMMU=y config option.
956
957	  In normal configurations this driver is only active when needed:
958	  there's more than 3 GB of memory and the system contains a
959	  32-bit limited device.
960
961	  If unsure, say Y.
962
963config BOOT_VESA_SUPPORT
964	bool
965	help
966	  If true, at least one selected framebuffer driver can take advantage
967	  of VESA video modes set at an early boot stage via the vga= parameter.
968
969config MAXSMP
970	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
971	depends on X86_64 && SMP && DEBUG_KERNEL
972	select CPUMASK_OFFSTACK
973	help
974	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
975	  If unsure, say N.
976
977#
978# The maximum number of CPUs supported:
979#
980# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
981# and which can be configured interactively in the
982# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
983#
984# The ranges are different on 32-bit and 64-bit kernels, depending on
985# hardware capabilities and scalability features of the kernel.
986#
987# ( If MAXSMP is enabled we just use the highest possible value and disable
988#   interactive configuration. )
989#
990
991config NR_CPUS_RANGE_BEGIN
992	int
993	default NR_CPUS_RANGE_END if MAXSMP
994	default    1 if !SMP
995	default    2
996
997config NR_CPUS_RANGE_END
998	int
999	depends on X86_32
1000	default    8 if  SMP
1001	default    1 if !SMP
1002
1003config NR_CPUS_RANGE_END
1004	int
1005	depends on X86_64
1006	default 8192 if  SMP && CPUMASK_OFFSTACK
1007	default  512 if  SMP && !CPUMASK_OFFSTACK
1008	default    1 if !SMP
1009
1010config NR_CPUS_DEFAULT
1011	int
1012	depends on X86_32
1013	default    8 if  SMP
1014	default    1 if !SMP
1015
1016config NR_CPUS_DEFAULT
1017	int
1018	depends on X86_64
1019	default 8192 if  MAXSMP
1020	default   64 if  SMP
1021	default    1 if !SMP
1022
1023config NR_CPUS
1024	int "Maximum number of CPUs" if SMP && !MAXSMP
1025	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1026	default NR_CPUS_DEFAULT
1027	help
1028	  This allows you to specify the maximum number of CPUs which this
1029	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1030	  supported value is 8192, otherwise the maximum value is 512.  The
1031	  minimum value which makes sense is 2.
1032
1033	  This is purely to save memory: each supported CPU adds about 8KB
1034	  to the kernel image.
1035
1036config SCHED_CLUSTER
1037	bool "Cluster scheduler support"
1038	depends on SMP
1039	default y
1040	help
1041	  Cluster scheduler support improves the CPU scheduler's decision
1042	  making when dealing with machines that have clusters of CPUs.
1043	  Cluster usually means a couple of CPUs which are placed closely
1044	  by sharing mid-level caches, last-level cache tags or internal
1045	  busses.
1046
1047config SCHED_SMT
1048	def_bool y if SMP
1049
1050config SCHED_MC
1051	def_bool y
1052	prompt "Multi-core scheduler support"
1053	depends on SMP
1054	help
1055	  Multi-core scheduler support improves the CPU scheduler's decision
1056	  making when dealing with multi-core CPU chips at a cost of slightly
1057	  increased overhead in some places. If unsure say N here.
1058
1059config SCHED_MC_PRIO
1060	bool "CPU core priorities scheduler support"
1061	depends on SCHED_MC
1062	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1063	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1064	select CPU_FREQ
1065	default y
1066	help
1067	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1068	  core ordering determined at manufacturing time, which allows
1069	  certain cores to reach higher turbo frequencies (when running
1070	  single threaded workloads) than others.
1071
1072	  Enabling this kernel feature teaches the scheduler about
1073	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1074	  scheduler's CPU selection logic accordingly, so that higher
1075	  overall system performance can be achieved.
1076
1077	  This feature will have no effect on CPUs without this feature.
1078
1079	  If unsure say Y here.
1080
1081config UP_LATE_INIT
1082	def_bool y
1083	depends on !SMP && X86_LOCAL_APIC
1084
1085config X86_UP_APIC
1086	bool "Local APIC support on uniprocessors" if !PCI_MSI
1087	default PCI_MSI
1088	depends on X86_32 && !SMP
1089	help
1090	  A local APIC (Advanced Programmable Interrupt Controller) is an
1091	  integrated interrupt controller in the CPU. If you have a single-CPU
1092	  system which has a processor with a local APIC, you can say Y here to
1093	  enable and use it. If you say Y here even though your machine doesn't
1094	  have a local APIC, then the kernel will still run with no slowdown at
1095	  all. The local APIC supports CPU-generated self-interrupts (timer,
1096	  performance counters), and the NMI watchdog which detects hard
1097	  lockups.
1098
1099config X86_UP_IOAPIC
1100	bool "IO-APIC support on uniprocessors"
1101	depends on X86_UP_APIC
1102	help
1103	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1104	  SMP-capable replacement for PC-style interrupt controllers. Most
1105	  SMP systems and many recent uniprocessor systems have one.
1106
1107	  If you have a single-CPU system with an IO-APIC, you can say Y here
1108	  to use it. If you say Y here even though your machine doesn't have
1109	  an IO-APIC, then the kernel will still run with no slowdown at all.
1110
1111config X86_LOCAL_APIC
1112	def_bool y
1113	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1114	select IRQ_DOMAIN_HIERARCHY
1115
1116config ACPI_MADT_WAKEUP
1117	def_bool y
1118	depends on X86_64
1119	depends on ACPI
1120	depends on SMP
1121	depends on X86_LOCAL_APIC
1122
1123config X86_IO_APIC
1124	def_bool y
1125	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1126
1127config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1128	bool "Reroute for broken boot IRQs"
1129	depends on X86_IO_APIC
1130	help
1131	  This option enables a workaround that fixes a source of
1132	  spurious interrupts. This is recommended when threaded
1133	  interrupt handling is used on systems where the generation of
1134	  superfluous "boot interrupts" cannot be disabled.
1135
1136	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1137	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1138	  kernel does during interrupt handling). On chipsets where this
1139	  boot IRQ generation cannot be disabled, this workaround keeps
1140	  the original IRQ line masked so that only the equivalent "boot
1141	  IRQ" is delivered to the CPUs. The workaround also tells the
1142	  kernel to set up the IRQ handler on the boot IRQ line. In this
1143	  way only one interrupt is delivered to the kernel. Otherwise
1144	  the spurious second interrupt may cause the kernel to bring
1145	  down (vital) interrupt lines.
1146
1147	  Only affects "broken" chipsets. Interrupt sharing may be
1148	  increased on these systems.
1149
1150config X86_MCE
1151	bool "Machine Check / overheating reporting"
1152	select GENERIC_ALLOCATOR
1153	default y
1154	help
1155	  Machine Check support allows the processor to notify the
1156	  kernel if it detects a problem (e.g. overheating, data corruption).
1157	  The action the kernel takes depends on the severity of the problem,
1158	  ranging from warning messages to halting the machine.
1159
1160config X86_MCELOG_LEGACY
1161	bool "Support for deprecated /dev/mcelog character device"
1162	depends on X86_MCE
1163	help
1164	  Enable support for /dev/mcelog which is needed by the old mcelog
1165	  userspace logging daemon. Consider switching to the new generation
1166	  rasdaemon solution.
1167
1168config X86_MCE_INTEL
1169	def_bool y
1170	prompt "Intel MCE features"
1171	depends on X86_MCE && X86_LOCAL_APIC
1172	help
1173	  Additional support for intel specific MCE features such as
1174	  the thermal monitor.
1175
1176config X86_MCE_AMD
1177	def_bool y
1178	prompt "AMD MCE features"
1179	depends on X86_MCE && X86_LOCAL_APIC
1180	help
1181	  Additional support for AMD specific MCE features such as
1182	  the DRAM Error Threshold.
1183
1184config X86_ANCIENT_MCE
1185	bool "Support for old Pentium 5 / WinChip machine checks"
1186	depends on X86_32 && X86_MCE
1187	help
1188	  Include support for machine check handling on old Pentium 5 or WinChip
1189	  systems. These typically need to be enabled explicitly on the command
1190	  line.
1191
1192config X86_MCE_THRESHOLD
1193	depends on X86_MCE_AMD || X86_MCE_INTEL
1194	def_bool y
1195
1196config X86_MCE_INJECT
1197	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1198	tristate "Machine check injector support"
1199	help
1200	  Provide support for injecting machine checks for testing purposes.
1201	  If you don't know what a machine check is and you don't do kernel
1202	  QA it is safe to say n.
1203
1204source "arch/x86/events/Kconfig"
1205
1206config X86_LEGACY_VM86
1207	bool "Legacy VM86 support"
1208	depends on X86_32
1209	help
1210	  This option allows user programs to put the CPU into V8086
1211	  mode, which is an 80286-era approximation of 16-bit real mode.
1212
1213	  Some very old versions of X and/or vbetool require this option
1214	  for user mode setting.  Similarly, DOSEMU will use it if
1215	  available to accelerate real mode DOS programs.  However, any
1216	  recent version of DOSEMU, X, or vbetool should be fully
1217	  functional even without kernel VM86 support, as they will all
1218	  fall back to software emulation. Nevertheless, if you are using
1219	  a 16-bit DOS program where 16-bit performance matters, vm86
1220	  mode might be faster than emulation and you might want to
1221	  enable this option.
1222
1223	  Note that any app that works on a 64-bit kernel is unlikely to
1224	  need this option, as 64-bit kernels don't, and can't, support
1225	  V8086 mode. This option is also unrelated to 16-bit protected
1226	  mode and is not needed to run most 16-bit programs under Wine.
1227
1228	  Enabling this option increases the complexity of the kernel
1229	  and slows down exception handling a tiny bit.
1230
1231	  If unsure, say N here.
1232
1233config VM86
1234	bool
1235	default X86_LEGACY_VM86
1236
1237config X86_16BIT
1238	bool "Enable support for 16-bit segments" if EXPERT
1239	default y
1240	depends on MODIFY_LDT_SYSCALL
1241	help
1242	  This option is required by programs like Wine to run 16-bit
1243	  protected mode legacy code on x86 processors.  Disabling
1244	  this option saves about 300 bytes on i386, or around 6K text
1245	  plus 16K runtime memory on x86-64,
1246
1247config X86_ESPFIX32
1248	def_bool y
1249	depends on X86_16BIT && X86_32
1250
1251config X86_ESPFIX64
1252	def_bool y
1253	depends on X86_16BIT && X86_64
1254
1255config X86_VSYSCALL_EMULATION
1256	bool "Enable vsyscall emulation" if EXPERT
1257	default y
1258	depends on X86_64
1259	help
1260	  This enables emulation of the legacy vsyscall page.  Disabling
1261	  it is roughly equivalent to booting with vsyscall=none, except
1262	  that it will also disable the helpful warning if a program
1263	  tries to use a vsyscall.  With this option set to N, offending
1264	  programs will just segfault, citing addresses of the form
1265	  0xffffffffff600?00.
1266
1267	  This option is required by many programs built before 2013, and
1268	  care should be used even with newer programs if set to N.
1269
1270	  Disabling this option saves about 7K of kernel size and
1271	  possibly 4K of additional runtime pagetable memory.
1272
1273config X86_IOPL_IOPERM
1274	bool "IOPERM and IOPL Emulation"
1275	default y
1276	help
1277	  This enables the ioperm() and iopl() syscalls which are necessary
1278	  for legacy applications.
1279
1280	  Legacy IOPL support is an overbroad mechanism which allows user
1281	  space aside of accessing all 65536 I/O ports also to disable
1282	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1283	  capabilities and permission from potentially active security
1284	  modules.
1285
1286	  The emulation restricts the functionality of the syscall to
1287	  only allowing the full range I/O port access, but prevents the
1288	  ability to disable interrupts from user space which would be
1289	  granted if the hardware IOPL mechanism would be used.
1290
1291config TOSHIBA
1292	tristate "Toshiba Laptop support"
1293	depends on X86_32
1294	help
1295	  This adds a driver to safely access the System Management Mode of
1296	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1297	  not work on models with a Phoenix BIOS. The System Management Mode
1298	  is used to set the BIOS and power saving options on Toshiba portables.
1299
1300	  For information on utilities to make use of this driver see the
1301	  Toshiba Linux utilities web site at:
1302	  <http://www.buzzard.org.uk/toshiba/>.
1303
1304	  Say Y if you intend to run this kernel on a Toshiba portable.
1305	  Say N otherwise.
1306
1307config X86_REBOOTFIXUPS
1308	bool "Enable X86 board specific fixups for reboot"
1309	depends on X86_32
1310	help
1311	  This enables chipset and/or board specific fixups to be done
1312	  in order to get reboot to work correctly. This is only needed on
1313	  some combinations of hardware and BIOS. The symptom, for which
1314	  this config is intended, is when reboot ends with a stalled/hung
1315	  system.
1316
1317	  Currently, the only fixup is for the Geode machines using
1318	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1319
1320	  Say Y if you want to enable the fixup. Currently, it's safe to
1321	  enable this option even if you don't need it.
1322	  Say N otherwise.
1323
1324config MICROCODE
1325	def_bool y
1326	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1327	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1328
1329config MICROCODE_INITRD32
1330	def_bool y
1331	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1332
1333config MICROCODE_LATE_LOADING
1334	bool "Late microcode loading (DANGEROUS)"
1335	default n
1336	depends on MICROCODE && SMP
1337	help
1338	  Loading microcode late, when the system is up and executing instructions
1339	  is a tricky business and should be avoided if possible. Just the sequence
1340	  of synchronizing all cores and SMT threads is one fragile dance which does
1341	  not guarantee that cores might not softlock after the loading. Therefore,
1342	  use this at your own risk. Late loading taints the kernel unless the
1343	  microcode header indicates that it is safe for late loading via the
1344	  minimal revision check. This minimal revision check can be enforced on
1345	  the kernel command line with "microcode.minrev=Y".
1346
1347config MICROCODE_LATE_FORCE_MINREV
1348	bool "Enforce late microcode loading minimal revision check"
1349	default n
1350	depends on MICROCODE_LATE_LOADING
1351	help
1352	  To prevent that users load microcode late which modifies already
1353	  in use features, newer microcode patches have a minimum revision field
1354	  in the microcode header, which tells the kernel which minimum
1355	  revision must be active in the CPU to safely load that new microcode
1356	  late into the running system. If disabled the check will not
1357	  be enforced but the kernel will be tainted when the minimal
1358	  revision check fails.
1359
1360	  This minimal revision check can also be controlled via the
1361	  "microcode.minrev" parameter on the kernel command line.
1362
1363	  If unsure say Y.
1364
1365config X86_MSR
1366	tristate "/dev/cpu/*/msr - Model-specific register support"
1367	help
1368	  This device gives privileged processes access to the x86
1369	  Model-Specific Registers (MSRs).  It is a character device with
1370	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1371	  MSR accesses are directed to a specific CPU on multi-processor
1372	  systems.
1373
1374config X86_CPUID
1375	tristate "/dev/cpu/*/cpuid - CPU information support"
1376	help
1377	  This device gives processes access to the x86 CPUID instruction to
1378	  be executed on a specific processor.  It is a character device
1379	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1380	  /dev/cpu/31/cpuid.
1381
1382config HIGHMEM4G
1383	bool "High Memory Support"
1384	depends on X86_32
1385	help
1386	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1387	  However, the address space of 32-bit x86 processors is only 4
1388	  Gigabytes large. That means that, if you have a large amount of
1389	  physical memory, not all of it can be "permanently mapped" by the
1390	  kernel. The physical memory that's not permanently mapped is called
1391	  "high memory".
1392
1393	  If you are compiling a kernel which will never run on a machine with
1394	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1395	  choice and suitable for most users). This will result in a "3GB/1GB"
1396	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1397	  space and the remaining part of the 4GB virtual memory space is used
1398	  by the kernel to permanently map as much physical memory as
1399	  possible.
1400
1401	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1402	  answer "Y" here.
1403
1404	  If unsure, say N.
1405
1406choice
1407	prompt "Memory split" if EXPERT
1408	default VMSPLIT_3G
1409	depends on X86_32
1410	help
1411	  Select the desired split between kernel and user memory.
1412
1413	  If the address range available to the kernel is less than the
1414	  physical memory installed, the remaining memory will be available
1415	  as "high memory". Accessing high memory is a little more costly
1416	  than low memory, as it needs to be mapped into the kernel first.
1417	  Note that increasing the kernel address space limits the range
1418	  available to user programs, making the address space there
1419	  tighter.  Selecting anything other than the default 3G/1G split
1420	  will also likely make your kernel incompatible with binary-only
1421	  kernel modules.
1422
1423	  If you are not absolutely sure what you are doing, leave this
1424	  option alone!
1425
1426	config VMSPLIT_3G
1427		bool "3G/1G user/kernel split"
1428	config VMSPLIT_3G_OPT
1429		depends on !X86_PAE
1430		bool "3G/1G user/kernel split (for full 1G low memory)"
1431	config VMSPLIT_2G
1432		bool "2G/2G user/kernel split"
1433	config VMSPLIT_2G_OPT
1434		depends on !X86_PAE
1435		bool "2G/2G user/kernel split (for full 2G low memory)"
1436	config VMSPLIT_1G
1437		bool "1G/3G user/kernel split"
1438endchoice
1439
1440config PAGE_OFFSET
1441	hex
1442	default 0xB0000000 if VMSPLIT_3G_OPT
1443	default 0x80000000 if VMSPLIT_2G
1444	default 0x78000000 if VMSPLIT_2G_OPT
1445	default 0x40000000 if VMSPLIT_1G
1446	default 0xC0000000
1447	depends on X86_32
1448
1449config HIGHMEM
1450	def_bool HIGHMEM4G
1451
1452config X86_PAE
1453	bool "PAE (Physical Address Extension) Support"
1454	depends on X86_32 && X86_HAVE_PAE
1455	select PHYS_ADDR_T_64BIT
1456	help
1457	  PAE is required for NX support, and furthermore enables
1458	  larger swapspace support for non-overcommit purposes. It
1459	  has the cost of more pagetable lookup overhead, and also
1460	  consumes more pagetable space per process.
1461
1462config X86_DIRECT_GBPAGES
1463	def_bool y
1464	depends on X86_64
1465	help
1466	  Certain kernel features effectively disable kernel
1467	  linear 1 GB mappings (even if the CPU otherwise
1468	  supports them), so don't confuse the user by printing
1469	  that we have them enabled.
1470
1471config X86_CPA_STATISTICS
1472	bool "Enable statistic for Change Page Attribute"
1473	depends on DEBUG_FS
1474	help
1475	  Expose statistics about the Change Page Attribute mechanism, which
1476	  helps to determine the effectiveness of preserving large and huge
1477	  page mappings when mapping protections are changed.
1478
1479config X86_MEM_ENCRYPT
1480	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1481	select DYNAMIC_PHYSICAL_MASK
1482	def_bool n
1483
1484config AMD_MEM_ENCRYPT
1485	bool "AMD Secure Memory Encryption (SME) support"
1486	depends on X86_64 && CPU_SUP_AMD
1487	depends on EFI_STUB
1488	select DMA_COHERENT_POOL
1489	select ARCH_USE_MEMREMAP_PROT
1490	select INSTRUCTION_DECODER
1491	select ARCH_HAS_CC_PLATFORM
1492	select X86_MEM_ENCRYPT
1493	select UNACCEPTED_MEMORY
1494	select CRYPTO_LIB_AESGCM
1495	help
1496	  Say yes to enable support for the encryption of system memory.
1497	  This requires an AMD processor that supports Secure Memory
1498	  Encryption (SME).
1499
1500# Common NUMA Features
1501config NUMA
1502	bool "NUMA Memory Allocation and Scheduler Support"
1503	depends on SMP
1504	depends on X86_64
1505	select USE_PERCPU_NUMA_NODE_ID
1506	select OF_NUMA if OF
1507	help
1508	  Enable NUMA (Non-Uniform Memory Access) support.
1509
1510	  The kernel will try to allocate memory used by a CPU on the
1511	  local memory controller of the CPU and add some more
1512	  NUMA awareness to the kernel.
1513
1514	  For 64-bit this is recommended if the system is Intel Core i7
1515	  (or later), AMD Opteron, or EM64T NUMA.
1516
1517	  Otherwise, you should say N.
1518
1519config AMD_NUMA
1520	def_bool y
1521	prompt "Old style AMD Opteron NUMA detection"
1522	depends on X86_64 && NUMA && PCI
1523	help
1524	  Enable AMD NUMA node topology detection.  You should say Y here if
1525	  you have a multi processor AMD system. This uses an old method to
1526	  read the NUMA configuration directly from the builtin Northbridge
1527	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1528	  which also takes priority if both are compiled in.
1529
1530config X86_64_ACPI_NUMA
1531	def_bool y
1532	prompt "ACPI NUMA detection"
1533	depends on X86_64 && NUMA && ACPI && PCI
1534	select ACPI_NUMA
1535	help
1536	  Enable ACPI SRAT based node topology detection.
1537
1538config NODES_SHIFT
1539	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1540	range 1 10
1541	default "10" if MAXSMP
1542	default "6" if X86_64
1543	default "3"
1544	depends on NUMA
1545	help
1546	  Specify the maximum number of NUMA Nodes available on the target
1547	  system.  Increases memory reserved to accommodate various tables.
1548
1549config ARCH_FLATMEM_ENABLE
1550	def_bool y
1551	depends on X86_32 && !NUMA
1552
1553config ARCH_SPARSEMEM_ENABLE
1554	def_bool y
1555	select SPARSEMEM_STATIC if X86_32
1556	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1557	select SPARSEMEM_VMEMMAP if X86_64
1558
1559config ARCH_SPARSEMEM_DEFAULT
1560	def_bool X86_64 || (NUMA && X86_32)
1561
1562config ARCH_SELECT_MEMORY_MODEL
1563	def_bool y
1564	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1565
1566config ARCH_MEMORY_PROBE
1567	bool "Enable sysfs memory/probe interface"
1568	depends on MEMORY_HOTPLUG
1569	help
1570	  This option enables a sysfs memory/probe interface for testing.
1571	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1572	  If you are unsure how to answer this question, answer N.
1573
1574config ARCH_PROC_KCORE_TEXT
1575	def_bool y
1576	depends on X86_64 && PROC_KCORE
1577
1578config ILLEGAL_POINTER_VALUE
1579	hex
1580	default 0 if X86_32
1581	default 0xdead000000000000 if X86_64
1582
1583config X86_PMEM_LEGACY_DEVICE
1584	bool
1585
1586config X86_PMEM_LEGACY
1587	tristate "Support non-standard NVDIMMs and ADR protected memory"
1588	depends on PHYS_ADDR_T_64BIT
1589	depends on BLK_DEV
1590	select X86_PMEM_LEGACY_DEVICE
1591	select NUMA_KEEP_MEMINFO if NUMA
1592	select LIBNVDIMM
1593	help
1594	  Treat memory marked using the non-standard e820 type of 12 as used
1595	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1596	  The kernel will offer these regions to the 'pmem' driver so
1597	  they can be used for persistent storage.
1598
1599	  Say Y if unsure.
1600
1601config X86_CHECK_BIOS_CORRUPTION
1602	bool "Check for low memory corruption"
1603	help
1604	  Periodically check for memory corruption in low memory, which
1605	  is suspected to be caused by BIOS.  Even when enabled in the
1606	  configuration, it is disabled at runtime.  Enable it by
1607	  setting "memory_corruption_check=1" on the kernel command
1608	  line.  By default it scans the low 64k of memory every 60
1609	  seconds; see the memory_corruption_check_size and
1610	  memory_corruption_check_period parameters in
1611	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1612
1613	  When enabled with the default parameters, this option has
1614	  almost no overhead, as it reserves a relatively small amount
1615	  of memory and scans it infrequently.  It both detects corruption
1616	  and prevents it from affecting the running system.
1617
1618	  It is, however, intended as a diagnostic tool; if repeatable
1619	  BIOS-originated corruption always affects the same memory,
1620	  you can use memmap= to prevent the kernel from using that
1621	  memory.
1622
1623config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1624	bool "Set the default setting of memory_corruption_check"
1625	depends on X86_CHECK_BIOS_CORRUPTION
1626	default y
1627	help
1628	  Set whether the default state of memory_corruption_check is
1629	  on or off.
1630
1631config MATH_EMULATION
1632	bool
1633	depends on MODIFY_LDT_SYSCALL
1634	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1635	help
1636	  Linux can emulate a math coprocessor (used for floating point
1637	  operations) if you don't have one. 486DX and Pentium processors have
1638	  a math coprocessor built in, 486SX and 386 do not, unless you added
1639	  a 487DX or 387, respectively. (The messages during boot time can
1640	  give you some hints here ["man dmesg"].) Everyone needs either a
1641	  coprocessor or this emulation.
1642
1643	  If you don't have a math coprocessor, you need to say Y here; if you
1644	  say Y here even though you have a coprocessor, the coprocessor will
1645	  be used nevertheless. (This behavior can be changed with the kernel
1646	  command line option "no387", which comes handy if your coprocessor
1647	  is broken. Try "man bootparam" or see the documentation of your boot
1648	  loader (lilo or loadlin) about how to pass options to the kernel at
1649	  boot time.) This means that it is a good idea to say Y here if you
1650	  intend to use this kernel on different machines.
1651
1652	  More information about the internals of the Linux math coprocessor
1653	  emulation can be found in <file:arch/x86/math-emu/README>.
1654
1655	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1656	  kernel, it won't hurt.
1657
1658config MTRR
1659	def_bool y
1660	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1661	help
1662	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1663	  the Memory Type Range Registers (MTRRs) may be used to control
1664	  processor access to memory ranges. This is most useful if you have
1665	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1666	  allows bus write transfers to be combined into a larger transfer
1667	  before bursting over the PCI/AGP bus. This can increase performance
1668	  of image write operations 2.5 times or more. Saying Y here creates a
1669	  /proc/mtrr file which may be used to manipulate your processor's
1670	  MTRRs. Typically the X server should use this.
1671
1672	  This code has a reasonably generic interface so that similar
1673	  control registers on other processors can be easily supported
1674	  as well:
1675
1676	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1677	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1678	  these, the ARRs are used to emulate the MTRRs.
1679	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1680	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1681	  write-combining. All of these processors are supported by this code
1682	  and it makes sense to say Y here if you have one of them.
1683
1684	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1685	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1686	  can lead to all sorts of problems, so it's good to say Y here.
1687
1688	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1689	  just add about 9 KB to your kernel.
1690
1691	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1692
1693config MTRR_SANITIZER
1694	def_bool y
1695	prompt "MTRR cleanup support"
1696	depends on MTRR
1697	help
1698	  Convert MTRR layout from continuous to discrete, so X drivers can
1699	  add writeback entries.
1700
1701	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1702	  The largest mtrr entry size for a continuous block can be set with
1703	  mtrr_chunk_size.
1704
1705	  If unsure, say Y.
1706
1707config MTRR_SANITIZER_ENABLE_DEFAULT
1708	int "MTRR cleanup enable value (0-1)"
1709	range 0 1
1710	default "0"
1711	depends on MTRR_SANITIZER
1712	help
1713	  Enable mtrr cleanup default value
1714
1715config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1716	int "MTRR cleanup spare reg num (0-7)"
1717	range 0 7
1718	default "1"
1719	depends on MTRR_SANITIZER
1720	help
1721	  mtrr cleanup spare entries default, it can be changed via
1722	  mtrr_spare_reg_nr=N on the kernel command line.
1723
1724config X86_PAT
1725	def_bool y
1726	prompt "x86 PAT support" if EXPERT
1727	depends on MTRR
1728	select ARCH_USES_PG_ARCH_2
1729	help
1730	  Use PAT attributes to setup page level cache control.
1731
1732	  PATs are the modern equivalents of MTRRs and are much more
1733	  flexible than MTRRs.
1734
1735	  Say N here if you see bootup problems (boot crash, boot hang,
1736	  spontaneous reboots) or a non-working video driver.
1737
1738	  If unsure, say Y.
1739
1740config X86_UMIP
1741	def_bool y
1742	prompt "User Mode Instruction Prevention" if EXPERT
1743	help
1744	  User Mode Instruction Prevention (UMIP) is a security feature in
1745	  some x86 processors. If enabled, a general protection fault is
1746	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1747	  executed in user mode. These instructions unnecessarily expose
1748	  information about the hardware state.
1749
1750	  The vast majority of applications do not use these instructions.
1751	  For the very few that do, software emulation is provided in
1752	  specific cases in protected and virtual-8086 modes. Emulated
1753	  results are dummy.
1754
1755config CC_HAS_IBT
1756	# GCC >= 9 and binutils >= 2.29
1757	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1758	# Clang/LLVM >= 14
1759	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1760	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1761	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1762		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1763		  $(as-instr,endbr64)
1764
1765config X86_CET
1766	def_bool n
1767	help
1768	  CET features configured (Shadow stack or IBT)
1769
1770config X86_KERNEL_IBT
1771	prompt "Indirect Branch Tracking"
1772	def_bool y
1773	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1774	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1775	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1776	select OBJTOOL
1777	select X86_CET
1778	help
1779	  Build the kernel with support for Indirect Branch Tracking, a
1780	  hardware support course-grain forward-edge Control Flow Integrity
1781	  protection. It enforces that all indirect calls must land on
1782	  an ENDBR instruction, as such, the compiler will instrument the
1783	  code with them to make this happen.
1784
1785	  In addition to building the kernel with IBT, seal all functions that
1786	  are not indirect call targets, avoiding them ever becoming one.
1787
1788	  This requires LTO like objtool runs and will slow down the build. It
1789	  does significantly reduce the number of ENDBR instructions in the
1790	  kernel image.
1791
1792config X86_INTEL_MEMORY_PROTECTION_KEYS
1793	prompt "Memory Protection Keys"
1794	def_bool y
1795	# Note: only available in 64-bit mode
1796	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1797	select ARCH_USES_HIGH_VMA_FLAGS
1798	select ARCH_HAS_PKEYS
1799	help
1800	  Memory Protection Keys provides a mechanism for enforcing
1801	  page-based protections, but without requiring modification of the
1802	  page tables when an application changes protection domains.
1803
1804	  For details, see Documentation/core-api/protection-keys.rst
1805
1806	  If unsure, say y.
1807
1808config ARCH_PKEY_BITS
1809	int
1810	default 4
1811
1812choice
1813	prompt "TSX enable mode"
1814	depends on CPU_SUP_INTEL
1815	default X86_INTEL_TSX_MODE_OFF
1816	help
1817	  Intel's TSX (Transactional Synchronization Extensions) feature
1818	  allows to optimize locking protocols through lock elision which
1819	  can lead to a noticeable performance boost.
1820
1821	  On the other hand it has been shown that TSX can be exploited
1822	  to form side channel attacks (e.g. TAA) and chances are there
1823	  will be more of those attacks discovered in the future.
1824
1825	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1826	  might override this decision by tsx=on the command line parameter.
1827	  Even with TSX enabled, the kernel will attempt to enable the best
1828	  possible TAA mitigation setting depending on the microcode available
1829	  for the particular machine.
1830
1831	  This option allows to set the default tsx mode between tsx=on, =off
1832	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1833	  details.
1834
1835	  Say off if not sure, auto if TSX is in use but it should be used on safe
1836	  platforms or on if TSX is in use and the security aspect of tsx is not
1837	  relevant.
1838
1839config X86_INTEL_TSX_MODE_OFF
1840	bool "off"
1841	help
1842	  TSX is disabled if possible - equals to tsx=off command line parameter.
1843
1844config X86_INTEL_TSX_MODE_ON
1845	bool "on"
1846	help
1847	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1848	  line parameter.
1849
1850config X86_INTEL_TSX_MODE_AUTO
1851	bool "auto"
1852	help
1853	  TSX is enabled on TSX capable HW that is believed to be safe against
1854	  side channel attacks- equals the tsx=auto command line parameter.
1855endchoice
1856
1857config X86_SGX
1858	bool "Software Guard eXtensions (SGX)"
1859	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1860	select CRYPTO_LIB_SHA256
1861	select MMU_NOTIFIER
1862	select NUMA_KEEP_MEMINFO if NUMA
1863	select XARRAY_MULTI
1864	help
1865	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1866	  that can be used by applications to set aside private regions of code
1867	  and data, referred to as enclaves. An enclave's private memory can
1868	  only be accessed by code running within the enclave. Accesses from
1869	  outside the enclave, including other enclaves, are disallowed by
1870	  hardware.
1871
1872	  If unsure, say N.
1873
1874config X86_USER_SHADOW_STACK
1875	bool "X86 userspace shadow stack"
1876	depends on AS_WRUSS
1877	depends on X86_64
1878	select ARCH_USES_HIGH_VMA_FLAGS
1879	select ARCH_HAS_USER_SHADOW_STACK
1880	select X86_CET
1881	help
1882	  Shadow stack protection is a hardware feature that detects function
1883	  return address corruption.  This helps mitigate ROP attacks.
1884	  Applications must be enabled to use it, and old userspace does not
1885	  get protection "for free".
1886
1887	  CPUs supporting shadow stacks were first released in 2020.
1888
1889	  See Documentation/arch/x86/shstk.rst for more information.
1890
1891	  If unsure, say N.
1892
1893config INTEL_TDX_HOST
1894	bool "Intel Trust Domain Extensions (TDX) host support"
1895	depends on CPU_SUP_INTEL
1896	depends on X86_64
1897	depends on KVM_INTEL
1898	depends on X86_X2APIC
1899	select ARCH_KEEP_MEMBLOCK
1900	depends on CONTIG_ALLOC
1901	depends on !KEXEC_CORE
1902	depends on X86_MCE
1903	help
1904	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1905	  host and certain physical attacks.  This option enables necessary TDX
1906	  support in the host kernel to run confidential VMs.
1907
1908	  If unsure, say N.
1909
1910config EFI
1911	bool "EFI runtime service support"
1912	depends on ACPI
1913	select UCS2_STRING
1914	select EFI_RUNTIME_WRAPPERS
1915	select ARCH_USE_MEMREMAP_PROT
1916	select EFI_RUNTIME_MAP if KEXEC_CORE
1917	help
1918	  This enables the kernel to use EFI runtime services that are
1919	  available (such as the EFI variable services).
1920
1921	  This option is only useful on systems that have EFI firmware.
1922	  In addition, you should use the latest ELILO loader available
1923	  at <http://elilo.sourceforge.net> in order to take advantage
1924	  of EFI runtime services. However, even with this option, the
1925	  resultant kernel should continue to boot on existing non-EFI
1926	  platforms.
1927
1928config EFI_STUB
1929	bool "EFI stub support"
1930	depends on EFI
1931	select RELOCATABLE
1932	help
1933	  This kernel feature allows a bzImage to be loaded directly
1934	  by EFI firmware without the use of a bootloader.
1935
1936	  See Documentation/admin-guide/efi-stub.rst for more information.
1937
1938config EFI_HANDOVER_PROTOCOL
1939	bool "EFI handover protocol (DEPRECATED)"
1940	depends on EFI_STUB
1941	default y
1942	help
1943	  Select this in order to include support for the deprecated EFI
1944	  handover protocol, which defines alternative entry points into the
1945	  EFI stub.  This is a practice that has no basis in the UEFI
1946	  specification, and requires a priori knowledge on the part of the
1947	  bootloader about Linux/x86 specific ways of passing the command line
1948	  and initrd, and where in memory those assets may be loaded.
1949
1950	  If in doubt, say Y. Even though the corresponding support is not
1951	  present in upstream GRUB or other bootloaders, most distros build
1952	  GRUB with numerous downstream patches applied, and may rely on the
1953	  handover protocol as as result.
1954
1955config EFI_MIXED
1956	bool "EFI mixed-mode support"
1957	depends on EFI_STUB && X86_64
1958	help
1959	  Enabling this feature allows a 64-bit kernel to be booted
1960	  on a 32-bit firmware, provided that your CPU supports 64-bit
1961	  mode.
1962
1963	  Note that it is not possible to boot a mixed-mode enabled
1964	  kernel via the EFI boot stub - a bootloader that supports
1965	  the EFI handover protocol must be used.
1966
1967	  If unsure, say N.
1968
1969config EFI_RUNTIME_MAP
1970	bool "Export EFI runtime maps to sysfs" if EXPERT
1971	depends on EFI
1972	help
1973	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1974	  That memory map is required by the 2nd kernel to set up EFI virtual
1975	  mappings after kexec, but can also be used for debugging purposes.
1976
1977	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1978
1979source "kernel/Kconfig.hz"
1980
1981config ARCH_SUPPORTS_KEXEC
1982	def_bool y
1983
1984config ARCH_SUPPORTS_KEXEC_FILE
1985	def_bool X86_64
1986
1987config ARCH_SELECTS_KEXEC_FILE
1988	def_bool y
1989	depends on KEXEC_FILE
1990	select HAVE_IMA_KEXEC if IMA
1991
1992config ARCH_SUPPORTS_KEXEC_PURGATORY
1993	def_bool y
1994
1995config ARCH_SUPPORTS_KEXEC_SIG
1996	def_bool y
1997
1998config ARCH_SUPPORTS_KEXEC_SIG_FORCE
1999	def_bool y
2000
2001config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2002	def_bool y
2003
2004config ARCH_SUPPORTS_KEXEC_JUMP
2005	def_bool y
2006
2007config ARCH_SUPPORTS_KEXEC_HANDOVER
2008	def_bool X86_64
2009
2010config ARCH_SUPPORTS_CRASH_DUMP
2011	def_bool X86_64 || (X86_32 && HIGHMEM)
2012
2013config ARCH_DEFAULT_CRASH_DUMP
2014	def_bool y
2015
2016config ARCH_SUPPORTS_CRASH_HOTPLUG
2017	def_bool y
2018
2019config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2020	def_bool CRASH_RESERVE
2021
2022config PHYSICAL_START
2023	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2024	default "0x1000000"
2025	help
2026	  This gives the physical address where the kernel is loaded.
2027
2028	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2029	  will decompress itself to above physical address and run from there.
2030	  Otherwise, bzImage will run from the address where it has been loaded
2031	  by the boot loader. The only exception is if it is loaded below the
2032	  above physical address, in which case it will relocate itself there.
2033
2034	  In normal kdump cases one does not have to set/change this option
2035	  as now bzImage can be compiled as a completely relocatable image
2036	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2037	  address. This option is mainly useful for the folks who don't want
2038	  to use a bzImage for capturing the crash dump and want to use a
2039	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2040	  to be specifically compiled to run from a specific memory area
2041	  (normally a reserved region) and this option comes handy.
2042
2043	  So if you are using bzImage for capturing the crash dump,
2044	  leave the value here unchanged to 0x1000000 and set
2045	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2046	  for capturing the crash dump change this value to start of
2047	  the reserved region.  In other words, it can be set based on
2048	  the "X" value as specified in the "crashkernel=YM@XM"
2049	  command line boot parameter passed to the panic-ed
2050	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2051	  for more details about crash dumps.
2052
2053	  Usage of bzImage for capturing the crash dump is recommended as
2054	  one does not have to build two kernels. Same kernel can be used
2055	  as production kernel and capture kernel. Above option should have
2056	  gone away after relocatable bzImage support is introduced. But it
2057	  is present because there are users out there who continue to use
2058	  vmlinux for dump capture. This option should go away down the
2059	  line.
2060
2061	  Don't change this unless you know what you are doing.
2062
2063config RELOCATABLE
2064	bool "Build a relocatable kernel"
2065	default y
2066	help
2067	  This builds a kernel image that retains relocation information
2068	  so it can be loaded someplace besides the default 1MB.
2069	  The relocations tend to make the kernel binary about 10% larger,
2070	  but are discarded at runtime.
2071
2072	  One use is for the kexec on panic case where the recovery kernel
2073	  must live at a different physical address than the primary
2074	  kernel.
2075
2076	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2077	  it has been loaded at and the compile time physical address
2078	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2079
2080config RANDOMIZE_BASE
2081	bool "Randomize the address of the kernel image (KASLR)"
2082	depends on RELOCATABLE
2083	default y
2084	help
2085	  In support of Kernel Address Space Layout Randomization (KASLR),
2086	  this randomizes the physical address at which the kernel image
2087	  is decompressed and the virtual address where the kernel
2088	  image is mapped, as a security feature that deters exploit
2089	  attempts relying on knowledge of the location of kernel
2090	  code internals.
2091
2092	  On 64-bit, the kernel physical and virtual addresses are
2093	  randomized separately. The physical address will be anywhere
2094	  between 16MB and the top of physical memory (up to 64TB). The
2095	  virtual address will be randomized from 16MB up to 1GB (9 bits
2096	  of entropy). Note that this also reduces the memory space
2097	  available to kernel modules from 1.5GB to 1GB.
2098
2099	  On 32-bit, the kernel physical and virtual addresses are
2100	  randomized together. They will be randomized from 16MB up to
2101	  512MB (8 bits of entropy).
2102
2103	  Entropy is generated using the RDRAND instruction if it is
2104	  supported. If RDTSC is supported, its value is mixed into
2105	  the entropy pool as well. If neither RDRAND nor RDTSC are
2106	  supported, then entropy is read from the i8254 timer. The
2107	  usable entropy is limited by the kernel being built using
2108	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2109	  minimum of 2MB. As a result, only 10 bits of entropy are
2110	  theoretically possible, but the implementations are further
2111	  limited due to memory layouts.
2112
2113	  If unsure, say Y.
2114
2115# Relocation on x86 needs some additional build support
2116config X86_NEED_RELOCS
2117	def_bool y
2118	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2119	select ARCH_VMLINUX_NEEDS_RELOCS
2120
2121config PHYSICAL_ALIGN
2122	hex "Alignment value to which kernel should be aligned"
2123	default "0x200000"
2124	range 0x2000 0x1000000 if X86_32
2125	range 0x200000 0x1000000 if X86_64
2126	help
2127	  This value puts the alignment restrictions on physical address
2128	  where kernel is loaded and run from. Kernel is compiled for an
2129	  address which meets above alignment restriction.
2130
2131	  If bootloader loads the kernel at a non-aligned address and
2132	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2133	  address aligned to above value and run from there.
2134
2135	  If bootloader loads the kernel at a non-aligned address and
2136	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2137	  load address and decompress itself to the address it has been
2138	  compiled for and run from there. The address for which kernel is
2139	  compiled already meets above alignment restrictions. Hence the
2140	  end result is that kernel runs from a physical address meeting
2141	  above alignment restrictions.
2142
2143	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2144	  this value must be a multiple of 0x200000.
2145
2146	  Don't change this unless you know what you are doing.
2147
2148config RANDOMIZE_MEMORY
2149	bool "Randomize the kernel memory sections"
2150	depends on X86_64
2151	depends on RANDOMIZE_BASE
2152	default RANDOMIZE_BASE
2153	help
2154	  Randomizes the base virtual address of kernel memory sections
2155	  (physical memory mapping, vmalloc & vmemmap). This security feature
2156	  makes exploits relying on predictable memory locations less reliable.
2157
2158	  The order of allocations remains unchanged. Entropy is generated in
2159	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2160	  configuration have in average 30,000 different possible virtual
2161	  addresses for each memory section.
2162
2163	  If unsure, say Y.
2164
2165config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2166	hex "Physical memory mapping padding" if EXPERT
2167	depends on RANDOMIZE_MEMORY
2168	default "0xa" if MEMORY_HOTPLUG
2169	default "0x0"
2170	range 0x1 0x40 if MEMORY_HOTPLUG
2171	range 0x0 0x40
2172	help
2173	  Define the padding in terabytes added to the existing physical
2174	  memory size during kernel memory randomization. It is useful
2175	  for memory hotplug support but reduces the entropy available for
2176	  address randomization.
2177
2178	  If unsure, leave at the default value.
2179
2180config ADDRESS_MASKING
2181	bool "Linear Address Masking support"
2182	depends on X86_64
2183	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2184	help
2185	  Linear Address Masking (LAM) modifies the checking that is applied
2186	  to 64-bit linear addresses, allowing software to use of the
2187	  untranslated address bits for metadata.
2188
2189	  The capability can be used for efficient address sanitizers (ASAN)
2190	  implementation and for optimizations in JITs.
2191
2192config HOTPLUG_CPU
2193	def_bool y
2194	depends on SMP
2195
2196config COMPAT_VDSO
2197	def_bool n
2198	prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)"
2199	depends on COMPAT_32
2200	help
2201	  Certain buggy versions of glibc will crash if they are
2202	  presented with a 32-bit vDSO that is not mapped at the address
2203	  indicated in its segment table.
2204
2205	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2206	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2207	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2208	  the only released version with the bug, but OpenSUSE 9
2209	  contains a buggy "glibc 2.3.2".
2210
2211	  The symptom of the bug is that everything crashes on startup, saying:
2212	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2213
2214	  Saying Y here changes the default value of the vdso32 boot
2215	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2216	  This works around the glibc bug but hurts performance.
2217
2218	  If unsure, say N: if you are compiling your own kernel, you
2219	  are unlikely to be using a buggy version of glibc.
2220
2221choice
2222	prompt "vsyscall table for legacy applications"
2223	depends on X86_64
2224	default LEGACY_VSYSCALL_XONLY
2225	help
2226	  Legacy user code that does not know how to find the vDSO expects
2227	  to be able to issue three syscalls by calling fixed addresses in
2228	  kernel space. Since this location is not randomized with ASLR,
2229	  it can be used to assist security vulnerability exploitation.
2230
2231	  This setting can be changed at boot time via the kernel command
2232	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2233	  is deprecated and can only be enabled using the kernel command
2234	  line.
2235
2236	  On a system with recent enough glibc (2.14 or newer) and no
2237	  static binaries, you can say None without a performance penalty
2238	  to improve security.
2239
2240	  If unsure, select "Emulate execution only".
2241
2242	config LEGACY_VSYSCALL_XONLY
2243		bool "Emulate execution only"
2244		help
2245		  The kernel traps and emulates calls into the fixed vsyscall
2246		  address mapping and does not allow reads.  This
2247		  configuration is recommended when userspace might use the
2248		  legacy vsyscall area but support for legacy binary
2249		  instrumentation of legacy code is not needed.  It mitigates
2250		  certain uses of the vsyscall area as an ASLR-bypassing
2251		  buffer.
2252
2253	config LEGACY_VSYSCALL_NONE
2254		bool "None"
2255		help
2256		  There will be no vsyscall mapping at all. This will
2257		  eliminate any risk of ASLR bypass due to the vsyscall
2258		  fixed address mapping. Attempts to use the vsyscalls
2259		  will be reported to dmesg, so that either old or
2260		  malicious userspace programs can be identified.
2261
2262endchoice
2263
2264config CMDLINE_BOOL
2265	bool "Built-in kernel command line"
2266	help
2267	  Allow for specifying boot arguments to the kernel at
2268	  build time.  On some systems (e.g. embedded ones), it is
2269	  necessary or convenient to provide some or all of the
2270	  kernel boot arguments with the kernel itself (that is,
2271	  to not rely on the boot loader to provide them.)
2272
2273	  To compile command line arguments into the kernel,
2274	  set this option to 'Y', then fill in the
2275	  boot arguments in CONFIG_CMDLINE.
2276
2277	  Systems with fully functional boot loaders (i.e. non-embedded)
2278	  should leave this option set to 'N'.
2279
2280config CMDLINE
2281	string "Built-in kernel command string"
2282	depends on CMDLINE_BOOL
2283	default ""
2284	help
2285	  Enter arguments here that should be compiled into the kernel
2286	  image and used at boot time.  If the boot loader provides a
2287	  command line at boot time, it is appended to this string to
2288	  form the full kernel command line, when the system boots.
2289
2290	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2291	  change this behavior.
2292
2293	  In most cases, the command line (whether built-in or provided
2294	  by the boot loader) should specify the device for the root
2295	  file system.
2296
2297config CMDLINE_OVERRIDE
2298	bool "Built-in command line overrides boot loader arguments"
2299	depends on CMDLINE_BOOL && CMDLINE != ""
2300	help
2301	  Set this option to 'Y' to have the kernel ignore the boot loader
2302	  command line, and use ONLY the built-in command line.
2303
2304	  This is used to work around broken boot loaders.  This should
2305	  be set to 'N' under normal conditions.
2306
2307config MODIFY_LDT_SYSCALL
2308	bool "Enable the LDT (local descriptor table)" if EXPERT
2309	default y
2310	help
2311	  Linux can allow user programs to install a per-process x86
2312	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2313	  call.  This is required to run 16-bit or segmented code such as
2314	  DOSEMU or some Wine programs.  It is also used by some very old
2315	  threading libraries.
2316
2317	  Enabling this feature adds a small amount of overhead to
2318	  context switches and increases the low-level kernel attack
2319	  surface.  Disabling it removes the modify_ldt(2) system call.
2320
2321	  Saying 'N' here may make sense for embedded or server kernels.
2322
2323config STRICT_SIGALTSTACK_SIZE
2324	bool "Enforce strict size checking for sigaltstack"
2325	depends on DYNAMIC_SIGFRAME
2326	help
2327	  For historical reasons MINSIGSTKSZ is a constant which became
2328	  already too small with AVX512 support. Add a mechanism to
2329	  enforce strict checking of the sigaltstack size against the
2330	  real size of the FPU frame. This option enables the check
2331	  by default. It can also be controlled via the kernel command
2332	  line option 'strict_sas_size' independent of this config
2333	  switch. Enabling it might break existing applications which
2334	  allocate a too small sigaltstack but 'work' because they
2335	  never get a signal delivered.
2336
2337	  Say 'N' unless you want to really enforce this check.
2338
2339config CFI_AUTO_DEFAULT
2340	bool "Attempt to use FineIBT by default at boot time"
2341	depends on FINEIBT
2342	depends on !RUST || RUSTC_VERSION >= 108800
2343	default y
2344	help
2345	  Attempt to use FineIBT by default at boot time. If enabled,
2346	  this is the same as booting with "cfi=auto". If disabled,
2347	  this is the same as booting with "cfi=kcfi".
2348
2349source "kernel/livepatch/Kconfig"
2350
2351config X86_BUS_LOCK_DETECT
2352	bool "Split Lock Detect and Bus Lock Detect support"
2353	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2354	default y
2355	help
2356	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2357	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2358
2359endmenu
2360
2361config CC_HAS_NAMED_AS
2362	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2363	depends on CC_IS_GCC
2364
2365#
2366# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2367# are incompatible with named address spaces with GCC < 13.3
2368# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2369#
2370
2371config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2372	def_bool y
2373	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2374	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2375
2376config USE_X86_SEG_SUPPORT
2377	def_bool CC_HAS_NAMED_AS
2378	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2379
2380config CC_HAS_SLS
2381	def_bool $(cc-option,-mharden-sls=all)
2382
2383config CC_HAS_RETURN_THUNK
2384	def_bool $(cc-option,-mfunction-return=thunk-extern)
2385
2386config CC_HAS_ENTRY_PADDING
2387	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2388
2389config CC_HAS_KCFI_ARITY
2390	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2391	depends on CC_IS_CLANG && !RUST
2392
2393config FUNCTION_PADDING_CFI
2394	int
2395	default 59 if FUNCTION_ALIGNMENT_64B
2396	default 27 if FUNCTION_ALIGNMENT_32B
2397	default 11 if FUNCTION_ALIGNMENT_16B
2398	default  3 if FUNCTION_ALIGNMENT_8B
2399	default  0
2400
2401# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2402# except Kconfig can't do arithmetic :/
2403config FUNCTION_PADDING_BYTES
2404	int
2405	default FUNCTION_PADDING_CFI if CFI_CLANG
2406	default FUNCTION_ALIGNMENT
2407
2408config CALL_PADDING
2409	def_bool n
2410	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2411	select FUNCTION_ALIGNMENT_16B
2412
2413config FINEIBT
2414	def_bool y
2415	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
2416	select CALL_PADDING
2417
2418config FINEIBT_BHI
2419	def_bool y
2420	depends on FINEIBT && CC_HAS_KCFI_ARITY
2421
2422config HAVE_CALL_THUNKS
2423	def_bool y
2424	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2425
2426config CALL_THUNKS
2427	def_bool n
2428	select CALL_PADDING
2429
2430config PREFIX_SYMBOLS
2431	def_bool y
2432	depends on CALL_PADDING && !CFI_CLANG
2433
2434menuconfig CPU_MITIGATIONS
2435	bool "Mitigations for CPU vulnerabilities"
2436	default y
2437	help
2438	  Say Y here to enable options which enable mitigations for hardware
2439	  vulnerabilities (usually related to speculative execution).
2440	  Mitigations can be disabled or restricted to SMT systems at runtime
2441	  via the "mitigations" kernel parameter.
2442
2443	  If you say N, all mitigations will be disabled.  This CANNOT be
2444	  overridden at runtime.
2445
2446	  Say 'Y', unless you really know what you are doing.
2447
2448if CPU_MITIGATIONS
2449
2450config MITIGATION_PAGE_TABLE_ISOLATION
2451	bool "Remove the kernel mapping in user mode"
2452	default y
2453	depends on (X86_64 || X86_PAE)
2454	help
2455	  This feature reduces the number of hardware side channels by
2456	  ensuring that the majority of kernel addresses are not mapped
2457	  into userspace.
2458
2459	  See Documentation/arch/x86/pti.rst for more details.
2460
2461config MITIGATION_RETPOLINE
2462	bool "Avoid speculative indirect branches in kernel"
2463	select OBJTOOL if HAVE_OBJTOOL
2464	default y
2465	help
2466	  Compile kernel with the retpoline compiler options to guard against
2467	  kernel-to-user data leaks by avoiding speculative indirect
2468	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2469	  support for full protection. The kernel may run slower.
2470
2471config MITIGATION_RETHUNK
2472	bool "Enable return-thunks"
2473	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2474	select OBJTOOL if HAVE_OBJTOOL
2475	default y if X86_64
2476	help
2477	  Compile the kernel with the return-thunks compiler option to guard
2478	  against kernel-to-user data leaks by avoiding return speculation.
2479	  Requires a compiler with -mfunction-return=thunk-extern
2480	  support for full protection. The kernel may run slower.
2481
2482config MITIGATION_UNRET_ENTRY
2483	bool "Enable UNRET on kernel entry"
2484	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2485	default y
2486	help
2487	  Compile the kernel with support for the retbleed=unret mitigation.
2488
2489config MITIGATION_CALL_DEPTH_TRACKING
2490	bool "Mitigate RSB underflow with call depth tracking"
2491	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2492	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2493	select CALL_THUNKS
2494	default y
2495	help
2496	  Compile the kernel with call depth tracking to mitigate the Intel
2497	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2498	  by default and needs to be enabled on the kernel command line via the
2499	  retbleed=stuff option. For non-affected systems the overhead of this
2500	  option is marginal as the call depth tracking is using run-time
2501	  generated call thunks in a compiler generated padding area and call
2502	  patching. This increases text size by ~5%. For non affected systems
2503	  this space is unused. On affected SKL systems this results in a
2504	  significant performance gain over the IBRS mitigation.
2505
2506config CALL_THUNKS_DEBUG
2507	bool "Enable call thunks and call depth tracking debugging"
2508	depends on MITIGATION_CALL_DEPTH_TRACKING
2509	select FUNCTION_ALIGNMENT_32B
2510	default n
2511	help
2512	  Enable call/ret counters for imbalance detection and build in
2513	  a noisy dmesg about callthunks generation and call patching for
2514	  trouble shooting. The debug prints need to be enabled on the
2515	  kernel command line with 'debug-callthunks'.
2516	  Only enable this when you are debugging call thunks as this
2517	  creates a noticeable runtime overhead. If unsure say N.
2518
2519config MITIGATION_IBPB_ENTRY
2520	bool "Enable IBPB on kernel entry"
2521	depends on CPU_SUP_AMD && X86_64
2522	default y
2523	help
2524	  Compile the kernel with support for the retbleed=ibpb and
2525	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2526
2527config MITIGATION_IBRS_ENTRY
2528	bool "Enable IBRS on kernel entry"
2529	depends on CPU_SUP_INTEL && X86_64
2530	default y
2531	help
2532	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2533	  This mitigates both spectre_v2 and retbleed at great cost to
2534	  performance.
2535
2536config MITIGATION_SRSO
2537	bool "Mitigate speculative RAS overflow on AMD"
2538	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2539	default y
2540	help
2541	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2542
2543config MITIGATION_SLS
2544	bool "Mitigate Straight-Line-Speculation"
2545	depends on CC_HAS_SLS && X86_64
2546	select OBJTOOL if HAVE_OBJTOOL
2547	default n
2548	help
2549	  Compile the kernel with straight-line-speculation options to guard
2550	  against straight line speculation. The kernel image might be slightly
2551	  larger.
2552
2553config MITIGATION_GDS
2554	bool "Mitigate Gather Data Sampling"
2555	depends on CPU_SUP_INTEL
2556	default y
2557	help
2558	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2559	  vulnerability which allows unprivileged speculative access to data
2560	  which was previously stored in vector registers. The attacker uses gather
2561	  instructions to infer the stale vector register data.
2562
2563config MITIGATION_RFDS
2564	bool "RFDS Mitigation"
2565	depends on CPU_SUP_INTEL
2566	default y
2567	help
2568	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2569	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2570	  allows unprivileged speculative access to stale data previously
2571	  stored in floating point, vector and integer registers.
2572	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2573
2574config MITIGATION_SPECTRE_BHI
2575	bool "Mitigate Spectre-BHB (Branch History Injection)"
2576	depends on CPU_SUP_INTEL
2577	default y
2578	help
2579	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2580	  where the branch history buffer is poisoned to speculatively steer
2581	  indirect branches.
2582	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2583
2584config MITIGATION_MDS
2585	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2586	depends on CPU_SUP_INTEL
2587	default y
2588	help
2589	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2590	  a hardware vulnerability which allows unprivileged speculative access
2591	  to data which is available in various CPU internal buffers.
2592	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2593
2594config MITIGATION_TAA
2595	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2596	depends on CPU_SUP_INTEL
2597	default y
2598	help
2599	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2600	  vulnerability that allows unprivileged speculative access to data
2601	  which is available in various CPU internal buffers by using
2602	  asynchronous aborts within an Intel TSX transactional region.
2603	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2604
2605config MITIGATION_MMIO_STALE_DATA
2606	bool "Mitigate MMIO Stale Data hardware bug"
2607	depends on CPU_SUP_INTEL
2608	default y
2609	help
2610	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2611	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2612	  vulnerabilities that can expose data. The vulnerabilities require the
2613	  attacker to have access to MMIO.
2614	  See also
2615	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2616
2617config MITIGATION_L1TF
2618	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2619	depends on CPU_SUP_INTEL
2620	default y
2621	help
2622	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2623	  hardware vulnerability which allows unprivileged speculative access to data
2624	  available in the Level 1 Data Cache.
2625	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2626
2627config MITIGATION_RETBLEED
2628	bool "Mitigate RETBleed hardware bug"
2629	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2630	default y
2631	help
2632	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2633	  with Return Instructions) vulnerability.  RETBleed is a speculative
2634	  execution attack which takes advantage of microarchitectural behavior
2635	  in many modern microprocessors, similar to Spectre v2. An
2636	  unprivileged attacker can use these flaws to bypass conventional
2637	  memory security restrictions to gain read access to privileged memory
2638	  that would otherwise be inaccessible.
2639
2640config MITIGATION_SPECTRE_V1
2641	bool "Mitigate SPECTRE V1 hardware bug"
2642	default y
2643	help
2644	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2645	  class of side channel attacks that takes advantage of speculative
2646	  execution that bypasses conditional branch instructions used for
2647	  memory access bounds check.
2648	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2649
2650config MITIGATION_SPECTRE_V2
2651	bool "Mitigate SPECTRE V2 hardware bug"
2652	default y
2653	help
2654	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2655	  V2 is a class of side channel attacks that takes advantage of
2656	  indirect branch predictors inside the processor. In Spectre variant 2
2657	  attacks, the attacker can steer speculative indirect branches in the
2658	  victim to gadget code by poisoning the branch target buffer of a CPU
2659	  used for predicting indirect branch addresses.
2660	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2661
2662config MITIGATION_SRBDS
2663	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2664	depends on CPU_SUP_INTEL
2665	default y
2666	help
2667	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2668	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2669	  Sampling (MDS) techniques to infer values returned from special
2670	  register accesses. An unprivileged user can extract values returned
2671	  from RDRAND and RDSEED executed on another core or sibling thread
2672	  using MDS techniques.
2673	  See also
2674	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2675
2676config MITIGATION_SSB
2677	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2678	default y
2679	help
2680	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2681	  hardware security vulnerability and its exploitation takes advantage
2682	  of speculative execution in a similar way to the Meltdown and Spectre
2683	  security vulnerabilities.
2684
2685config MITIGATION_ITS
2686	bool "Enable Indirect Target Selection mitigation"
2687	depends on CPU_SUP_INTEL && X86_64
2688	depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK
2689	select EXECMEM
2690	default y
2691	help
2692	  Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in
2693	  BPU on some Intel CPUs that may allow Spectre V2 style attacks. If
2694	  disabled, mitigation cannot be enabled via cmdline.
2695	  See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst>
2696
2697endif
2698
2699config ARCH_HAS_ADD_PAGES
2700	def_bool y
2701	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2702
2703menu "Power management and ACPI options"
2704
2705config ARCH_HIBERNATION_HEADER
2706	def_bool y
2707	depends on HIBERNATION
2708
2709source "kernel/power/Kconfig"
2710
2711source "drivers/acpi/Kconfig"
2712
2713config X86_APM_BOOT
2714	def_bool y
2715	depends on APM
2716
2717menuconfig APM
2718	tristate "APM (Advanced Power Management) BIOS support"
2719	depends on X86_32 && PM_SLEEP
2720	help
2721	  APM is a BIOS specification for saving power using several different
2722	  techniques. This is mostly useful for battery powered laptops with
2723	  APM compliant BIOSes. If you say Y here, the system time will be
2724	  reset after a RESUME operation, the /proc/apm device will provide
2725	  battery status information, and user-space programs will receive
2726	  notification of APM "events" (e.g. battery status change).
2727
2728	  If you select "Y" here, you can disable actual use of the APM
2729	  BIOS by passing the "apm=off" option to the kernel at boot time.
2730
2731	  Note that the APM support is almost completely disabled for
2732	  machines with more than one CPU.
2733
2734	  In order to use APM, you will need supporting software. For location
2735	  and more information, read <file:Documentation/power/apm-acpi.rst>
2736	  and the Battery Powered Linux mini-HOWTO, available from
2737	  <http://www.tldp.org/docs.html#howto>.
2738
2739	  This driver does not spin down disk drives (see the hdparm(8)
2740	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2741	  VESA-compliant "green" monitors.
2742
2743	  This driver does not support the TI 4000M TravelMate and the ACER
2744	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2745	  desktop machines also don't have compliant BIOSes, and this driver
2746	  may cause those machines to panic during the boot phase.
2747
2748	  Generally, if you don't have a battery in your machine, there isn't
2749	  much point in using this driver and you should say N. If you get
2750	  random kernel OOPSes or reboots that don't seem to be related to
2751	  anything, try disabling/enabling this option (or disabling/enabling
2752	  APM in your BIOS).
2753
2754	  Some other things you should try when experiencing seemingly random,
2755	  "weird" problems:
2756
2757	  1) make sure that you have enough swap space and that it is
2758	  enabled.
2759	  2) pass the "idle=poll" option to the kernel
2760	  3) switch on floating point emulation in the kernel and pass
2761	  the "no387" option to the kernel
2762	  4) pass the "floppy=nodma" option to the kernel
2763	  5) pass the "mem=4M" option to the kernel (thereby disabling
2764	  all but the first 4 MB of RAM)
2765	  6) make sure that the CPU is not over clocked.
2766	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2767	  8) disable the cache from your BIOS settings
2768	  9) install a fan for the video card or exchange video RAM
2769	  10) install a better fan for the CPU
2770	  11) exchange RAM chips
2771	  12) exchange the motherboard.
2772
2773	  To compile this driver as a module, choose M here: the
2774	  module will be called apm.
2775
2776if APM
2777
2778config APM_IGNORE_USER_SUSPEND
2779	bool "Ignore USER SUSPEND"
2780	help
2781	  This option will ignore USER SUSPEND requests. On machines with a
2782	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2783	  series notebooks, it is necessary to say Y because of a BIOS bug.
2784
2785config APM_DO_ENABLE
2786	bool "Enable PM at boot time"
2787	help
2788	  Enable APM features at boot time. From page 36 of the APM BIOS
2789	  specification: "When disabled, the APM BIOS does not automatically
2790	  power manage devices, enter the Standby State, enter the Suspend
2791	  State, or take power saving steps in response to CPU Idle calls."
2792	  This driver will make CPU Idle calls when Linux is idle (unless this
2793	  feature is turned off -- see "Do CPU IDLE calls", below). This
2794	  should always save battery power, but more complicated APM features
2795	  will be dependent on your BIOS implementation. You may need to turn
2796	  this option off if your computer hangs at boot time when using APM
2797	  support, or if it beeps continuously instead of suspending. Turn
2798	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2799	  T400CDT. This is off by default since most machines do fine without
2800	  this feature.
2801
2802config APM_CPU_IDLE
2803	depends on CPU_IDLE
2804	bool "Make CPU Idle calls when idle"
2805	help
2806	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2807	  On some machines, this can activate improved power savings, such as
2808	  a slowed CPU clock rate, when the machine is idle. These idle calls
2809	  are made after the idle loop has run for some length of time (e.g.,
2810	  333 mS). On some machines, this will cause a hang at boot time or
2811	  whenever the CPU becomes idle. (On machines with more than one CPU,
2812	  this option does nothing.)
2813
2814config APM_DISPLAY_BLANK
2815	bool "Enable console blanking using APM"
2816	help
2817	  Enable console blanking using the APM. Some laptops can use this to
2818	  turn off the LCD backlight when the screen blanker of the Linux
2819	  virtual console blanks the screen. Note that this is only used by
2820	  the virtual console screen blanker, and won't turn off the backlight
2821	  when using the X Window system. This also doesn't have anything to
2822	  do with your VESA-compliant power-saving monitor. Further, this
2823	  option doesn't work for all laptops -- it might not turn off your
2824	  backlight at all, or it might print a lot of errors to the console,
2825	  especially if you are using gpm.
2826
2827config APM_ALLOW_INTS
2828	bool "Allow interrupts during APM BIOS calls"
2829	help
2830	  Normally we disable external interrupts while we are making calls to
2831	  the APM BIOS as a measure to lessen the effects of a badly behaving
2832	  BIOS implementation.  The BIOS should reenable interrupts if it
2833	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2834	  many of the newer IBM Thinkpads.  If you experience hangs when you
2835	  suspend, try setting this to Y.  Otherwise, say N.
2836
2837endif # APM
2838
2839source "drivers/cpufreq/Kconfig"
2840
2841source "drivers/cpuidle/Kconfig"
2842
2843source "drivers/idle/Kconfig"
2844
2845endmenu
2846
2847menu "Bus options (PCI etc.)"
2848
2849choice
2850	prompt "PCI access mode"
2851	depends on X86_32 && PCI
2852	default PCI_GOANY
2853	help
2854	  On PCI systems, the BIOS can be used to detect the PCI devices and
2855	  determine their configuration. However, some old PCI motherboards
2856	  have BIOS bugs and may crash if this is done. Also, some embedded
2857	  PCI-based systems don't have any BIOS at all. Linux can also try to
2858	  detect the PCI hardware directly without using the BIOS.
2859
2860	  With this option, you can specify how Linux should detect the
2861	  PCI devices. If you choose "BIOS", the BIOS will be used,
2862	  if you choose "Direct", the BIOS won't be used, and if you
2863	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2864	  If you choose "Any", the kernel will try MMCONFIG, then the
2865	  direct access method and falls back to the BIOS if that doesn't
2866	  work. If unsure, go with the default, which is "Any".
2867
2868config PCI_GOBIOS
2869	bool "BIOS"
2870
2871config PCI_GOMMCONFIG
2872	bool "MMConfig"
2873
2874config PCI_GODIRECT
2875	bool "Direct"
2876
2877config PCI_GOOLPC
2878	bool "OLPC XO-1"
2879	depends on OLPC
2880
2881config PCI_GOANY
2882	bool "Any"
2883
2884endchoice
2885
2886config PCI_BIOS
2887	def_bool y
2888	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2889
2890# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2891config PCI_DIRECT
2892	def_bool y
2893	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2894
2895config PCI_MMCONFIG
2896	bool "Support mmconfig PCI config space access" if X86_64
2897	default y
2898	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2899	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2900	help
2901	  Add support for accessing the PCI configuration space as a memory
2902	  mapped area. It is the recommended method if the system supports
2903	  this (it must have PCI Express and ACPI for it to be available).
2904
2905	  In the unlikely case that enabling this configuration option causes
2906	  problems, the mechanism can be switched off with the 'pci=nommconf'
2907	  command line parameter.
2908
2909	  Say N only if you are sure that your platform does not support this
2910	  access method or you have problems caused by it.
2911
2912	  Say Y otherwise.
2913
2914config PCI_OLPC
2915	def_bool y
2916	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2917
2918config PCI_XEN
2919	def_bool y
2920	depends on PCI && XEN
2921
2922config MMCONF_FAM10H
2923	def_bool y
2924	depends on X86_64 && PCI_MMCONFIG && ACPI
2925
2926config PCI_CNB20LE_QUIRK
2927	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2928	depends on X86_32 && PCI
2929	help
2930	  Read the PCI windows out of the CNB20LE host bridge. This allows
2931	  PCI hotplug to work on systems with the CNB20LE chipset which do
2932	  not have ACPI.
2933
2934	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2935	  most probably only for Pentium III.
2936
2937	  To find out if you have such a chipset, search for a PCI device with
2938	  1166:0009 PCI IDs, for example by executing
2939		lspci -nn | grep '1166:0009'
2940	  The code is inactive if there is none.
2941
2942	  There's no public spec for this chipset, and this functionality
2943	  is known to be incomplete.
2944
2945	  You should say N unless you know you need this.
2946
2947config ISA_BUS
2948	bool "ISA bus support on modern systems" if EXPERT
2949	help
2950	  Expose ISA bus device drivers and options available for selection and
2951	  configuration. Enable this option if your target machine has an ISA
2952	  bus. ISA is an older system, displaced by PCI and newer bus
2953	  architectures -- if your target machine is modern, it probably does
2954	  not have an ISA bus.
2955
2956	  If unsure, say N.
2957
2958# x86_64 have no ISA slots, but can have ISA-style DMA.
2959config ISA_DMA_API
2960	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2961	default y
2962	help
2963	  Enables ISA-style DMA support for devices requiring such controllers.
2964	  If unsure, say Y.
2965
2966if X86_32
2967
2968config ISA
2969	bool "ISA support"
2970	help
2971	  Find out whether you have ISA slots on your motherboard.  ISA is the
2972	  name of a bus system, i.e. the way the CPU talks to the other stuff
2973	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2974	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2975	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2976
2977config SCx200
2978	tristate "NatSemi SCx200 support"
2979	help
2980	  This provides basic support for National Semiconductor's
2981	  (now AMD's) Geode processors.  The driver probes for the
2982	  PCI-IDs of several on-chip devices, so its a good dependency
2983	  for other scx200_* drivers.
2984
2985	  If compiled as a module, the driver is named scx200.
2986
2987config SCx200HR_TIMER
2988	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2989	depends on SCx200
2990	default y
2991	help
2992	  This driver provides a clocksource built upon the on-chip
2993	  27MHz high-resolution timer.  Its also a workaround for
2994	  NSC Geode SC-1100's buggy TSC, which loses time when the
2995	  processor goes idle (as is done by the scheduler).  The
2996	  other workaround is idle=poll boot option.
2997
2998config OLPC
2999	bool "One Laptop Per Child support"
3000	depends on !X86_PAE
3001	select GPIOLIB
3002	select OF
3003	select OF_PROMTREE
3004	select IRQ_DOMAIN
3005	select OLPC_EC
3006	help
3007	  Add support for detecting the unique features of the OLPC
3008	  XO hardware.
3009
3010config OLPC_XO1_PM
3011	bool "OLPC XO-1 Power Management"
3012	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3013	help
3014	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3015
3016config OLPC_XO1_RTC
3017	bool "OLPC XO-1 Real Time Clock"
3018	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3019	help
3020	  Add support for the XO-1 real time clock, which can be used as a
3021	  programmable wakeup source.
3022
3023config OLPC_XO1_SCI
3024	bool "OLPC XO-1 SCI extras"
3025	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3026	depends on INPUT=y
3027	select POWER_SUPPLY
3028	help
3029	  Add support for SCI-based features of the OLPC XO-1 laptop:
3030	   - EC-driven system wakeups
3031	   - Power button
3032	   - Ebook switch
3033	   - Lid switch
3034	   - AC adapter status updates
3035	   - Battery status updates
3036
3037config OLPC_XO15_SCI
3038	bool "OLPC XO-1.5 SCI extras"
3039	depends on OLPC && ACPI
3040	select POWER_SUPPLY
3041	help
3042	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3043	   - EC-driven system wakeups
3044	   - AC adapter status updates
3045	   - Battery status updates
3046
3047config GEODE_COMMON
3048	bool
3049
3050config ALIX
3051	bool "PCEngines ALIX System Support (LED setup)"
3052	select GPIOLIB
3053	select GEODE_COMMON
3054	help
3055	  This option enables system support for the PCEngines ALIX.
3056	  At present this just sets up LEDs for GPIO control on
3057	  ALIX2/3/6 boards.  However, other system specific setup should
3058	  get added here.
3059
3060	  Note: You must still enable the drivers for GPIO and LED support
3061	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3062
3063	  Note: You have to set alix.force=1 for boards with Award BIOS.
3064
3065config NET5501
3066	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3067	select GPIOLIB
3068	select GEODE_COMMON
3069	help
3070	  This option enables system support for the Soekris Engineering net5501.
3071
3072config GEOS
3073	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3074	select GPIOLIB
3075	select GEODE_COMMON
3076	depends on DMI
3077	help
3078	  This option enables system support for the Traverse Technologies GEOS.
3079
3080config TS5500
3081	bool "Technologic Systems TS-5500 platform support"
3082	depends on MELAN
3083	select CHECK_SIGNATURE
3084	select NEW_LEDS
3085	select LEDS_CLASS
3086	help
3087	  This option enables system support for the Technologic Systems TS-5500.
3088
3089endif # X86_32
3090
3091config AMD_NB
3092	def_bool y
3093	depends on AMD_NODE
3094
3095config AMD_NODE
3096	def_bool y
3097	depends on CPU_SUP_AMD && PCI
3098
3099endmenu
3100
3101menu "Binary Emulations"
3102
3103config IA32_EMULATION
3104	bool "IA32 Emulation"
3105	depends on X86_64
3106	select ARCH_WANT_OLD_COMPAT_IPC
3107	select BINFMT_ELF
3108	select COMPAT_OLD_SIGACTION
3109	help
3110	  Include code to run legacy 32-bit programs under a
3111	  64-bit kernel. You should likely turn this on, unless you're
3112	  100% sure that you don't have any 32-bit programs left.
3113
3114config IA32_EMULATION_DEFAULT_DISABLED
3115	bool "IA32 emulation disabled by default"
3116	default n
3117	depends on IA32_EMULATION
3118	help
3119	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3120	  processes and access to 32-bit syscalls. If unsure, leave it to its
3121	  default value.
3122
3123config X86_X32_ABI
3124	bool "x32 ABI for 64-bit mode"
3125	depends on X86_64
3126	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3127	# compressed debug sections to x86_x32 properly:
3128	# https://github.com/ClangBuiltLinux/linux/issues/514
3129	# https://github.com/ClangBuiltLinux/linux/issues/1141
3130	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3131	help
3132	  Include code to run binaries for the x32 native 32-bit ABI
3133	  for 64-bit processors.  An x32 process gets access to the
3134	  full 64-bit register file and wide data path while leaving
3135	  pointers at 32 bits for smaller memory footprint.
3136
3137config COMPAT_32
3138	def_bool y
3139	depends on IA32_EMULATION || X86_32
3140	select HAVE_UID16
3141	select OLD_SIGSUSPEND3
3142
3143config COMPAT
3144	def_bool y
3145	depends on IA32_EMULATION || X86_X32_ABI
3146
3147config COMPAT_FOR_U64_ALIGNMENT
3148	def_bool y
3149	depends on COMPAT
3150
3151endmenu
3152
3153config HAVE_ATOMIC_IOMAP
3154	def_bool y
3155	depends on X86_32
3156
3157source "arch/x86/kvm/Kconfig"
3158
3159source "arch/x86/Kconfig.cpufeatures"
3160
3161source "arch/x86/Kconfig.assembler"
3162