xref: /linux/arch/x86/Kconfig (revision 00a155c691befdb10bea52c91d4c8c930bdaf73a)
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 HAVE_DEBUG_STACKOVERFLOW
18	select KMAP_LOCAL
19	select MODULES_USE_ELF_REL
20	select OLD_SIGACTION
21	select ARCH_SPLIT_ARG64
22
23config X86_64
24	def_bool y
25	depends on 64BIT
26	# Options that are inherently 64-bit kernel only:
27	select ARCH_HAS_GIGANTIC_PAGE
28	select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
29	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30	select ARCH_SUPPORTS_PER_VMA_LOCK
31	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
32	select HAVE_ARCH_SOFT_DIRTY
33	select MODULES_USE_ELF_RELA
34	select NEED_DMA_MAP_STATE
35	select SWIOTLB
36	select ARCH_HAS_ELFCORE_COMPAT
37	select ZONE_DMA32
38	select EXECMEM if DYNAMIC_FTRACE
39	select ACPI_MRRM if ACPI
40
41config FORCE_DYNAMIC_FTRACE
42	def_bool y
43	depends on X86_32
44	depends on FUNCTION_TRACER
45	select DYNAMIC_FTRACE
46	help
47	  We keep the static function tracing (!DYNAMIC_FTRACE) around
48	  in order to test the non static function tracing in the
49	  generic code, as other architectures still use it. But we
50	  only need to keep it around for x86_64. No need to keep it
51	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
52#
53# Arch settings
54#
55# ( Note that options that are marked 'if X86_64' could in principle be
56#   ported to 32-bit as well. )
57#
58config X86
59	def_bool y
60	#
61	# Note: keep this list sorted alphabetically
62	#
63	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
64	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
65	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
66	select ARCH_32BIT_OFF_T			if X86_32
67	select ARCH_CLOCKSOURCE_INIT
68	select ARCH_CONFIGURES_CPU_MITIGATIONS
69	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
70	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
71	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
72	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
73	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
74	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
75	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
76	select ARCH_HAS_CPU_ATTACK_VECTORS	if CPU_MITIGATIONS
77	select ARCH_HAS_CACHE_LINE_SIZE
78	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
79	select ARCH_HAS_CPU_FINALIZE_INIT
80	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
81	select ARCH_HAS_CURRENT_STACK_POINTER
82	select ARCH_HAS_DEBUG_VIRTUAL
83	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
84	select ARCH_HAS_DEVMEM_IS_ALLOWED
85	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
86	select ARCH_HAS_EARLY_DEBUG		if KGDB
87	select ARCH_HAS_ELF_RANDOMIZE
88	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
89	select ARCH_HAS_FAST_MULTIPLIER
90	select ARCH_HAS_FORTIFY_SOURCE
91	select ARCH_HAS_GCOV_PROFILE_ALL
92	select ARCH_HAS_KCOV			if X86_64
93	select ARCH_HAS_KERNEL_FPU_SUPPORT
94	select ARCH_HAS_MEM_ENCRYPT
95	select ARCH_HAS_MEMBARRIER_SYNC_CORE
96	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
97	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
98	select ARCH_HAS_PMEM_API		if X86_64
99	select ARCH_HAS_PREEMPT_LAZY
100	select ARCH_HAS_PTDUMP
101	select ARCH_HAS_PTE_SPECIAL
102	select ARCH_HAS_HW_PTE_YOUNG
103	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
104	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
105	select ARCH_HAS_COPY_MC			if X86_64
106	select ARCH_HAS_SET_MEMORY
107	select ARCH_HAS_SET_DIRECT_MAP
108	select ARCH_HAS_STRICT_KERNEL_RWX
109	select ARCH_HAS_STRICT_MODULE_RWX
110	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
111	select ARCH_HAS_SYSCALL_WRAPPER
112	select ARCH_HAS_UBSAN
113	select ARCH_HAS_DEBUG_WX
114	select ARCH_HAS_ZONE_DMA_SET if EXPERT
115	select ARCH_HAVE_NMI_SAFE_CMPXCHG
116	select ARCH_HAVE_EXTRA_ELF_NOTES
117	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
118	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
119	select ARCH_MIGHT_HAVE_PC_PARPORT
120	select ARCH_MIGHT_HAVE_PC_SERIO
121	select ARCH_STACKWALK
122	select ARCH_SUPPORTS_ACPI
123	select ARCH_SUPPORTS_ATOMIC_RMW
124	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
125	select ARCH_SUPPORTS_HUGETLBFS
126	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
127	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
128	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
129	select ARCH_SUPPORTS_CFI		if X86_64
130	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI
131	select ARCH_SUPPORTS_LTO_CLANG
132	select ARCH_SUPPORTS_LTO_CLANG_THIN
133	select ARCH_SUPPORTS_RT
134	select ARCH_SUPPORTS_AUTOFDO_CLANG
135	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
136	select ARCH_USE_BUILTIN_BSWAP
137	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CX8
138	select ARCH_USE_MEMTEST
139	select ARCH_USE_QUEUED_RWLOCKS
140	select ARCH_USE_QUEUED_SPINLOCKS
141	select ARCH_USE_SYM_ANNOTATIONS
142	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
143	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
144	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
145	select ARCH_WANTS_NO_INSTR
146	select ARCH_WANT_GENERAL_HUGETLB
147	select ARCH_WANT_HUGE_PMD_SHARE		if X86_64
148	select ARCH_WANT_LD_ORPHAN_WARN
149	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
150	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
151	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
152	select ARCH_WANTS_THP_SWAP		if X86_64
153	select ARCH_HAS_PARANOID_L1D_FLUSH
154	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
155	select BUILDTIME_TABLE_SORT
156	select CLKEVT_I8253
157	select CLOCKSOURCE_WATCHDOG
158	# Word-size accesses may read uninitialized data past the trailing \0
159	# in strings and cause false KMSAN reports.
160	select DCACHE_WORD_ACCESS		if !KMSAN
161	select DYNAMIC_SIGFRAME
162	select EDAC_ATOMIC_SCRUB
163	select EDAC_SUPPORT
164	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
165	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
166	select GENERIC_CLOCKEVENTS_MIN_ADJUST
167	select GENERIC_CMOS_UPDATE
168	select GENERIC_CPU_AUTOPROBE
169	select GENERIC_CPU_DEVICES
170	select GENERIC_CPU_VULNERABILITIES
171	select GENERIC_EARLY_IOREMAP
172	select GENERIC_ENTRY
173	select GENERIC_IOMAP
174	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
175	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
176	select GENERIC_IRQ_MIGRATION		if SMP
177	select GENERIC_IRQ_PROBE
178	select GENERIC_IRQ_RESERVATION_MODE
179	select GENERIC_IRQ_SHOW
180	select GENERIC_PENDING_IRQ		if SMP
181	select GENERIC_SMP_IDLE_THREAD
182	select GENERIC_TIME_VSYSCALL
183	select GENERIC_GETTIMEOFDAY
184	select GENERIC_VDSO_OVERFLOW_PROTECT
185	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
186	select HARDIRQS_SW_RESEND
187	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
188	select HAS_IOPORT
189	select HAVE_ACPI_APEI			if ACPI
190	select HAVE_ACPI_APEI_NMI		if ACPI
191	select HAVE_ALIGNED_STRUCT_PAGE
192	select HAVE_ARCH_AUDITSYSCALL
193	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
194	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
195	select HAVE_ARCH_JUMP_LABEL
196	select HAVE_ARCH_JUMP_LABEL_RELATIVE
197	select HAVE_ARCH_KASAN			if X86_64
198	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
199	select HAVE_ARCH_KFENCE
200	select HAVE_ARCH_KMSAN			if X86_64
201	select HAVE_ARCH_KGDB
202	select HAVE_ARCH_KSTACK_ERASE
203	select HAVE_ARCH_MMAP_RND_BITS		if MMU
204	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
205	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
206	select HAVE_ARCH_PREL32_RELOCATIONS
207	select HAVE_ARCH_SECCOMP_FILTER
208	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
209	select HAVE_ARCH_TRACEHOOK
210	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
211	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
212	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
213	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
214	select HAVE_ARCH_VMAP_STACK		if X86_64
215	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
216	select HAVE_ARCH_WITHIN_STACK_FRAMES
217	select HAVE_ASM_MODVERSIONS
218	select HAVE_CMPXCHG_DOUBLE
219	select HAVE_CMPXCHG_LOCAL
220	select HAVE_CONTEXT_TRACKING_USER		if X86_64
221	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
222	select HAVE_C_RECORDMCOUNT
223	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
224	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
225	select HAVE_BUILDTIME_MCOUNT_SORT
226	select HAVE_DEBUG_KMEMLEAK
227	select HAVE_DMA_CONTIGUOUS
228	select HAVE_DYNAMIC_FTRACE
229	select HAVE_DYNAMIC_FTRACE_WITH_REGS
230	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
231	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
232	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
233	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
234	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
235	select HAVE_EBPF_JIT
236	select HAVE_EFFICIENT_UNALIGNED_ACCESS
237	select HAVE_EISA			if X86_32
238	select HAVE_EXIT_THREAD
239	select HAVE_GENERIC_TIF_BITS
240	select HAVE_GUP_FAST
241	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
242	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
243	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
244	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
245	select HAVE_FUNCTION_TRACER
246	select HAVE_GCC_PLUGINS
247	select HAVE_HW_BREAKPOINT
248	select HAVE_IOREMAP_PROT
249	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
250	select HAVE_IRQ_TIME_ACCOUNTING
251	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
252	select HAVE_KERNEL_BZIP2
253	select HAVE_KERNEL_GZIP
254	select HAVE_KERNEL_LZ4
255	select HAVE_KERNEL_LZMA
256	select HAVE_KERNEL_LZO
257	select HAVE_KERNEL_XZ
258	select HAVE_KERNEL_ZSTD
259	select HAVE_KPROBES
260	select HAVE_KPROBES_ON_FTRACE
261	select HAVE_FUNCTION_ERROR_INJECTION
262	select HAVE_KRETPROBES
263	select HAVE_RETHOOK
264	select HAVE_KLP_BUILD			if X86_64
265	select HAVE_LIVEPATCH			if X86_64
266	select HAVE_MIXED_BREAKPOINTS_REGS
267	select HAVE_MOD_ARCH_SPECIFIC
268	select HAVE_MOVE_PMD
269	select HAVE_MOVE_PUD
270	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
271	select HAVE_NMI
272	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
273	select HAVE_OBJTOOL			if X86_64
274	select HAVE_OPTPROBES
275	select HAVE_PAGE_SIZE_4KB
276	select HAVE_PCSPKR_PLATFORM
277	select HAVE_PERF_EVENTS
278	select HAVE_PERF_EVENTS_NMI
279	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
280	select HAVE_PCI
281	select HAVE_PERF_REGS
282	select HAVE_PERF_USER_STACK_DUMP
283	select MMU_GATHER_RCU_TABLE_FREE
284	select MMU_GATHER_MERGE_VMAS
285	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
286	select HAVE_REGS_AND_STACK_ACCESS_API
287	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
288	select HAVE_FUNCTION_ARG_ACCESS_API
289	select HAVE_SETUP_PER_CPU_AREA
290	select HAVE_SOFTIRQ_ON_OWN_STACK
291	select HAVE_STACKPROTECTOR
292	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
293	select HAVE_STATIC_CALL
294	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
295	select HAVE_PREEMPT_DYNAMIC_CALL
296	select HAVE_RSEQ
297	select HAVE_RUST			if X86_64
298	select HAVE_SYSCALL_TRACEPOINTS
299	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
300	select HAVE_UNSTABLE_SCHED_CLOCK
301	select HAVE_USER_RETURN_NOTIFIER
302	select HAVE_GENERIC_VDSO
303	select VDSO_GETRANDOM			if X86_64
304	select HOTPLUG_PARALLEL			if SMP && X86_64
305	select HOTPLUG_SMT			if SMP
306	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
307	select IRQ_FORCED_THREADING
308	select LOCK_MM_AND_FIND_VMA
309	select NEED_PER_CPU_EMBED_FIRST_CHUNK
310	select NEED_PER_CPU_PAGE_FIRST_CHUNK
311	select NEED_SG_DMA_LENGTH
312	select NUMA_MEMBLKS			if NUMA
313	select PCI_DOMAINS			if PCI
314	select PCI_LOCKLESS_CONFIG		if PCI
315	select PERF_EVENTS
316	select RTC_LIB
317	select RTC_MC146818_LIB
318	select SPARSE_IRQ
319	select SYSCTL_EXCEPTION_TRACE
320	select THREAD_INFO_IN_TASK
321	select TRACE_IRQFLAGS_SUPPORT
322	select TRACE_IRQFLAGS_NMI_SUPPORT
323	select USER_STACKTRACE_SUPPORT
324	select HAVE_ARCH_KCSAN			if X86_64
325	select PROC_PID_ARCH_STATUS		if PROC_FS
326	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
327	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
328	select FUNCTION_ALIGNMENT_4B
329	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
330	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
331	select ARCH_SUPPORTS_PT_RECLAIM		if X86_64
332	select ARCH_SUPPORTS_SCHED_SMT		if SMP
333	select SCHED_SMT			if SMP
334	select ARCH_SUPPORTS_SCHED_CLUSTER	if SMP
335	select ARCH_SUPPORTS_SCHED_MC		if SMP
336
337config INSTRUCTION_DECODER
338	def_bool y
339	depends on KPROBES || PERF_EVENTS || UPROBES
340
341config OUTPUT_FORMAT
342	string
343	default "elf32-i386" if X86_32
344	default "elf64-x86-64" if X86_64
345
346config LOCKDEP_SUPPORT
347	def_bool y
348
349config STACKTRACE_SUPPORT
350	def_bool y
351
352config MMU
353	def_bool y
354
355config ARCH_MMAP_RND_BITS_MIN
356	default 28 if 64BIT
357	default 8
358
359config ARCH_MMAP_RND_BITS_MAX
360	default 32 if 64BIT
361	default 16
362
363config ARCH_MMAP_RND_COMPAT_BITS_MIN
364	default 8
365
366config ARCH_MMAP_RND_COMPAT_BITS_MAX
367	default 16
368
369config SBUS
370	bool
371
372config GENERIC_ISA_DMA
373	def_bool y
374	depends on ISA_DMA_API
375
376config GENERIC_CSUM
377	bool
378	default y if KMSAN || KASAN
379
380config GENERIC_BUG
381	def_bool y
382	depends on BUG
383	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
384
385config GENERIC_BUG_RELATIVE_POINTERS
386	bool
387
388config ARCH_MAY_HAVE_PC_FDC
389	def_bool y
390	depends on ISA_DMA_API
391
392config GENERIC_CALIBRATE_DELAY
393	def_bool y
394
395config ARCH_HAS_CPU_RELAX
396	def_bool y
397
398config ARCH_HIBERNATION_POSSIBLE
399	def_bool y
400
401config ARCH_SUSPEND_POSSIBLE
402	def_bool y
403
404config AUDIT_ARCH
405	def_bool y if X86_64
406
407config KASAN_SHADOW_OFFSET
408	hex
409	depends on KASAN
410	default 0xdffffc0000000000
411
412config HAVE_INTEL_TXT
413	def_bool y
414	depends on INTEL_IOMMU && ACPI
415
416config ARCH_SUPPORTS_UPROBES
417	def_bool y
418
419config FIX_EARLYCON_MEM
420	def_bool y
421
422config DYNAMIC_PHYSICAL_MASK
423	bool
424
425config PGTABLE_LEVELS
426	int
427	default 5 if X86_64
428	default 3 if X86_PAE
429	default 2
430
431menu "Processor type and features"
432
433config SMP
434	bool "Symmetric multi-processing support"
435	help
436	  This enables support for systems with more than one CPU. If you have
437	  a system with only one CPU, say N. If you have a system with more
438	  than one CPU, say Y.
439
440	  If you say N here, the kernel will run on uni- and multiprocessor
441	  machines, but will use only one CPU of a multiprocessor machine. If
442	  you say Y here, the kernel will run on many, but not all,
443	  uniprocessor machines. On a uniprocessor machine, the kernel
444	  will run faster if you say N here.
445
446	  Note that if you say Y here and choose architecture "586" or
447	  "Pentium" under "Processor family", the kernel will not work on 486
448	  architectures. Similarly, multiprocessor kernels for the "PPro"
449	  architecture may not work on all Pentium based boards.
450
451	  People using multiprocessor machines who say Y here should also say
452	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
453	  Management" code will be disabled if you say Y here.
454
455	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
456	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
457	  <http://www.tldp.org/docs.html#howto>.
458
459	  If you don't know what to do here, say N.
460
461config X86_X2APIC
462	bool "x2APIC interrupt controller architecture support"
463	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
464	default y
465	help
466	  x2APIC is an interrupt controller architecture, a component of which
467	  (the local APIC) is present in the CPU. It allows faster access to
468	  the local APIC and supports a larger number of CPUs in the system
469	  than the predecessors.
470
471	  x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs
472	  in 2019, but it can be disabled by the BIOS. It is also frequently
473	  emulated in virtual machines, even when the host CPU does not support
474	  it. Support in the CPU can be checked by executing
475		grep x2apic /proc/cpuinfo
476
477	  If this configuration option is disabled, the kernel will boot with
478	  very reduced functionality and performance on some platforms that
479	  have x2APIC enabled. On the other hand, on hardware that does not
480	  support x2APIC, a kernel with this option enabled will just fallback
481	  to older APIC implementations.
482
483	  If in doubt, say Y.
484
485config AMD_SECURE_AVIC
486	bool "AMD Secure AVIC"
487	depends on AMD_MEM_ENCRYPT && X86_X2APIC
488	help
489	  Enable this to get AMD Secure AVIC support on guests that have this feature.
490
491	  AMD Secure AVIC provides hardware acceleration for performance sensitive
492	  APIC accesses and support for managing guest owned APIC state for SEV-SNP
493	  guests. Secure AVIC does not support xAPIC mode. It has functional
494	  dependency on x2apic being enabled in the guest.
495
496	  If you don't know what to do here, say N.
497
498config X86_POSTED_MSI
499	bool "Enable MSI and MSI-x delivery by posted interrupts"
500	depends on X86_64 && IRQ_REMAP
501	help
502	  This enables MSIs that are under interrupt remapping to be delivered as
503	  posted interrupts to the host kernel. Interrupt throughput can
504	  potentially be improved by coalescing CPU notifications during high
505	  frequency bursts.
506
507	  If you don't know what to do here, say N.
508
509config X86_MPPARSE
510	bool "Enable MPS table" if ACPI
511	default y
512	depends on X86_LOCAL_APIC
513	help
514	  For old smp systems that do not have proper acpi support. Newer systems
515	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
516
517config X86_CPU_RESCTRL
518	bool "x86 CPU resource control support"
519	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
520	depends on MISC_FILESYSTEMS
521	select ARCH_HAS_CPU_RESCTRL
522	select RESCTRL_FS
523	select RESCTRL_FS_PSEUDO_LOCK
524	help
525	  Enable x86 CPU resource control support.
526
527	  Provide support for the allocation and monitoring of system resources
528	  usage by the CPU.
529
530	  Intel calls this Intel Resource Director Technology
531	  (Intel(R) RDT). More information about RDT can be found in the
532	  Intel x86 Architecture Software Developer Manual.
533
534	  AMD calls this AMD Platform Quality of Service (AMD QoS).
535	  More information about AMD QoS can be found in the AMD64 Technology
536	  Platform Quality of Service Extensions manual.
537
538	  Say N if unsure.
539
540config X86_FRED
541	bool "Flexible Return and Event Delivery"
542	depends on X86_64
543	help
544	  When enabled, try to use Flexible Return and Event Delivery
545	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
546	  ring transitions and exception/interrupt handling if the
547	  system supports it.
548
549config X86_EXTENDED_PLATFORM
550	bool "Support for extended (non-PC) x86 platforms"
551	default y
552	help
553	  If you disable this option then the kernel will only support
554	  standard PC platforms. (which covers the vast majority of
555	  systems out there.)
556
557	  If you enable this option then you'll be able to select support
558	  for the following non-PC x86 platforms, depending on the value of
559	  CONFIG_64BIT.
560
561	  32-bit platforms (CONFIG_64BIT=n):
562		Goldfish (mostly Android emulator)
563		Intel CE media processor (CE4100) SoC
564		Intel Quark
565		RDC R-321x SoC
566
567	  64-bit platforms (CONFIG_64BIT=y):
568		Numascale NumaChip
569		ScaleMP vSMP
570		SGI Ultraviolet
571		Merrifield/Moorefield MID devices
572		Goldfish (mostly Android emulator)
573
574	  If you have one of these systems, or if you want to build a
575	  generic distribution kernel, say Y here - otherwise say N.
576
577# This is an alphabetically sorted list of 64 bit extended platforms
578# Please maintain the alphabetic order if and when there are additions
579config X86_NUMACHIP
580	bool "Numascale NumaChip"
581	depends on X86_64
582	depends on X86_EXTENDED_PLATFORM
583	depends on NUMA
584	depends on SMP
585	depends on X86_X2APIC
586	depends on PCI_MMCONFIG
587	help
588	  Adds support for Numascale NumaChip large-SMP systems. Needed to
589	  enable more than ~168 cores.
590	  If you don't have one of these, you should say N here.
591
592config X86_VSMP
593	bool "ScaleMP vSMP"
594	select HYPERVISOR_GUEST
595	select PARAVIRT
596	depends on X86_64 && PCI
597	depends on X86_EXTENDED_PLATFORM
598	depends on SMP
599	help
600	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
601	  supposed to run on these EM64T-based machines.  Only choose this option
602	  if you have one of these machines.
603
604config X86_UV
605	bool "SGI Ultraviolet"
606	depends on X86_64
607	depends on X86_EXTENDED_PLATFORM
608	depends on NUMA
609	depends on EFI
610	depends on KEXEC_CORE
611	depends on X86_X2APIC
612	depends on PCI
613	help
614	  This option is needed in order to support SGI Ultraviolet systems.
615	  If you don't have one of these, you should say N here.
616
617config X86_INTEL_MID
618	bool "Intel Z34xx/Z35xx MID platform support"
619	depends on X86_EXTENDED_PLATFORM
620	depends on X86_PLATFORM_DEVICES
621	depends on PCI
622	depends on X86_64 || (EXPERT && PCI_GOANY)
623	depends on X86_IO_APIC
624	select I2C
625	select DW_APB_TIMER
626	select INTEL_SCU_PCI
627	help
628	  Select to build a kernel capable of supporting 64-bit Intel MID
629	  (Mobile Internet Device) platform systems which do not have
630	  the PCI legacy interfaces.
631
632	  The only supported devices are the 22nm Merrified (Z34xx)
633	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
634	  a small number of Android devices such as the Asus Zenfone 2,
635	  Asus FonePad 8 and Dell Venue 7.
636
637	  If you are building for a PC class system or non-MID tablet
638	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
639
640	  Intel MID platforms are based on an Intel processor and chipset which
641	  consume less power than most of the x86 derivatives.
642
643config X86_GOLDFISH
644	bool "Goldfish (Virtual Platform)"
645	depends on X86_EXTENDED_PLATFORM
646	help
647	  Enable support for the Goldfish virtual platform used primarily
648	  for Android development. Unless you are building for the Android
649	  Goldfish emulator say N here.
650
651# Following is an alphabetically sorted list of 32 bit extended platforms
652# Please maintain the alphabetic order if and when there are additions
653
654config X86_INTEL_CE
655	bool "CE4100 TV platform"
656	depends on PCI
657	depends on PCI_GODIRECT
658	depends on X86_IO_APIC
659	depends on X86_32
660	depends on X86_EXTENDED_PLATFORM
661	select X86_REBOOTFIXUPS
662	select OF
663	select OF_EARLY_FLATTREE
664	help
665	  Select for the Intel CE media processor (CE4100) SOC.
666	  This option compiles in support for the CE4100 SOC for settop
667	  boxes and media devices.
668
669config X86_INTEL_QUARK
670	bool "Intel Quark platform support"
671	depends on X86_32
672	depends on X86_EXTENDED_PLATFORM
673	depends on X86_PLATFORM_DEVICES
674	depends on X86_TSC
675	depends on PCI
676	depends on PCI_GOANY
677	depends on X86_IO_APIC
678	select IOSF_MBI
679	select INTEL_IMR
680	select COMMON_CLK
681	help
682	  Select to include support for Quark X1000 SoC.
683	  Say Y here if you have a Quark based system such as the Arduino
684	  compatible Intel Galileo.
685
686config X86_RDC321X
687	bool "RDC R-321x SoC"
688	depends on X86_32
689	depends on X86_EXTENDED_PLATFORM
690	select M486
691	select X86_REBOOTFIXUPS
692	help
693	  This option is needed for RDC R-321x system-on-chip, also known
694	  as R-8610-(G).
695	  If you don't have one of these chips, you should say N here.
696
697config X86_INTEL_LPSS
698	bool "Intel Low Power Subsystem Support"
699	depends on X86 && ACPI && PCI
700	select COMMON_CLK
701	select PINCTRL
702	select IOSF_MBI
703	help
704	  Select to build support for Intel Low Power Subsystem such as
705	  found on Intel Lynxpoint PCH. Selecting this option enables
706	  things like clock tree (common clock framework) and pincontrol
707	  which are needed by the LPSS peripheral drivers.
708
709config X86_AMD_PLATFORM_DEVICE
710	bool "AMD ACPI2Platform devices support"
711	depends on ACPI
712	select COMMON_CLK
713	select PINCTRL
714	help
715	  Select to interpret AMD specific ACPI device to platform device
716	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
717	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
718	  implemented under PINCTRL subsystem.
719
720config IOSF_MBI
721	tristate "Intel SoC IOSF Sideband support for SoC platforms"
722	depends on PCI
723	help
724	  This option enables sideband register access support for Intel SoC
725	  platforms. On these platforms the IOSF sideband is used in lieu of
726	  MSR's for some register accesses, mostly but not limited to thermal
727	  and power. Drivers may query the availability of this device to
728	  determine if they need the sideband in order to work on these
729	  platforms. The sideband is available on the following SoC products.
730	  This list is not meant to be exclusive.
731	   - BayTrail
732	   - Braswell
733	   - Quark
734
735	  You should say Y if you are running a kernel on one of these SoC's.
736
737config IOSF_MBI_DEBUG
738	bool "Enable IOSF sideband access through debugfs"
739	depends on IOSF_MBI && DEBUG_FS
740	help
741	  Select this option to expose the IOSF sideband access registers (MCR,
742	  MDR, MCRX) through debugfs to write and read register information from
743	  different units on the SoC. This is most useful for obtaining device
744	  state information for debug and analysis. As this is a general access
745	  mechanism, users of this option would have specific knowledge of the
746	  device they want to access.
747
748	  If you don't require the option or are in doubt, say N.
749
750config X86_SUPPORTS_MEMORY_FAILURE
751	def_bool y
752	# MCE code calls memory_failure():
753	depends on X86_MCE
754	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
755	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
756	depends on X86_64 || !SPARSEMEM
757	select ARCH_SUPPORTS_MEMORY_FAILURE
758
759config X86_32_IRIS
760	tristate "Eurobraille/Iris poweroff module"
761	depends on X86_32
762	help
763	  The Iris machines from EuroBraille do not have APM or ACPI support
764	  to shut themselves down properly.  A special I/O sequence is
765	  needed to do so, which is what this module does at
766	  kernel shutdown.
767
768	  This is only for Iris machines from EuroBraille.
769
770	  If unused, say N.
771
772config SCHED_OMIT_FRAME_POINTER
773	def_bool y
774	prompt "Single-depth WCHAN output"
775	depends on X86
776	help
777	  Calculate simpler /proc/<PID>/wchan values. If this option
778	  is disabled then wchan values will recurse back to the
779	  caller function. This provides more accurate wchan values,
780	  at the expense of slightly more scheduling overhead.
781
782	  If in doubt, say "Y".
783
784menuconfig HYPERVISOR_GUEST
785	bool "Linux guest support"
786	help
787	  Say Y here to enable options for running Linux under various hyper-
788	  visors. This option enables basic hypervisor detection and platform
789	  setup.
790
791	  If you say N, all options in this submenu will be skipped and
792	  disabled, and Linux guest support won't be built in.
793
794if HYPERVISOR_GUEST
795
796config PARAVIRT
797	bool "Enable paravirtualization code"
798	depends on HAVE_STATIC_CALL
799	help
800	  This changes the kernel so it can modify itself when it is run
801	  under a hypervisor, potentially improving performance significantly
802	  over full virtualization.  However, when run without a hypervisor
803	  the kernel is theoretically slower and slightly larger.
804
805config PARAVIRT_XXL
806	bool
807	depends on X86_64
808
809config PARAVIRT_DEBUG
810	bool "paravirt-ops debugging"
811	depends on PARAVIRT && DEBUG_KERNEL
812	help
813	  Enable to debug paravirt_ops internals.  Specifically, BUG if
814	  a paravirt_op is missing when it is called.
815
816config PARAVIRT_SPINLOCKS
817	bool "Paravirtualization layer for spinlocks"
818	depends on PARAVIRT && SMP
819	help
820	  Paravirtualized spinlocks allow a pvops backend to replace the
821	  spinlock implementation with something virtualization-friendly
822	  (for example, block the virtual CPU rather than spinning).
823
824	  It has a minimal impact on native kernels and gives a nice performance
825	  benefit on paravirtualized KVM / Xen kernels.
826
827	  If you are unsure how to answer this question, answer Y.
828
829config X86_HV_CALLBACK_VECTOR
830	def_bool n
831
832source "arch/x86/xen/Kconfig"
833
834config KVM_GUEST
835	bool "KVM Guest support (including kvmclock)"
836	depends on PARAVIRT
837	select PARAVIRT_CLOCK
838	select ARCH_CPUIDLE_HALTPOLL
839	select X86_HV_CALLBACK_VECTOR
840	default y
841	help
842	  This option enables various optimizations for running under the KVM
843	  hypervisor. It includes a paravirtualized clock, so that instead
844	  of relying on a PIT (or probably other) emulation by the
845	  underlying device model, the host provides the guest with
846	  timing infrastructure such as time of day, and system time
847
848config ARCH_CPUIDLE_HALTPOLL
849	def_bool n
850	prompt "Disable host haltpoll when loading haltpoll driver"
851	help
852	  If virtualized under KVM, disable host haltpoll.
853
854config PVH
855	bool "Support for running PVH guests"
856	help
857	  This option enables the PVH entry point for guest virtual machines
858	  as specified in the x86/HVM direct boot ABI.
859
860config PARAVIRT_TIME_ACCOUNTING
861	bool "Paravirtual steal time accounting"
862	depends on PARAVIRT
863	help
864	  Select this option to enable fine granularity task steal time
865	  accounting. Time spent executing other tasks in parallel with
866	  the current vCPU is discounted from the vCPU power. To account for
867	  that, there can be a small performance impact.
868
869	  If in doubt, say N here.
870
871config PARAVIRT_CLOCK
872	bool
873
874config JAILHOUSE_GUEST
875	bool "Jailhouse non-root cell support"
876	depends on X86_64 && PCI
877	select X86_PM_TIMER
878	help
879	  This option allows to run Linux as guest in a Jailhouse non-root
880	  cell. You can leave this option disabled if you only want to start
881	  Jailhouse and run Linux afterwards in the root cell.
882
883config ACRN_GUEST
884	bool "ACRN Guest support"
885	depends on X86_64
886	select X86_HV_CALLBACK_VECTOR
887	help
888	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
889	  a flexible, lightweight reference open-source hypervisor, built with
890	  real-time and safety-criticality in mind. It is built for embedded
891	  IOT with small footprint and real-time features. More details can be
892	  found in https://projectacrn.org/.
893
894config BHYVE_GUEST
895	bool "Bhyve (BSD Hypervisor) Guest support"
896	depends on X86_64
897	help
898	  This option allows to run Linux to recognise when it is running as a
899	  guest in the Bhyve hypervisor, and to support more than 255 vCPUs when
900	  when doing so. More details about Bhyve can be found at https://bhyve.org
901	  and https://wiki.freebsd.org/bhyve/.
902
903config INTEL_TDX_GUEST
904	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
905	depends on X86_64 && CPU_SUP_INTEL
906	depends on X86_X2APIC
907	depends on EFI_STUB
908	depends on PARAVIRT
909	select ARCH_HAS_CC_PLATFORM
910	select X86_MEM_ENCRYPT
911	select X86_MCE
912	select UNACCEPTED_MEMORY
913	help
914	  Support running as a guest under Intel TDX.  Without this support,
915	  the guest kernel can not boot or run under TDX.
916	  TDX includes memory encryption and integrity capabilities
917	  which protect the confidentiality and integrity of guest
918	  memory contents and CPU state. TDX guests are protected from
919	  some attacks from the VMM.
920
921endif # HYPERVISOR_GUEST
922
923source "arch/x86/Kconfig.cpu"
924
925config HPET_TIMER
926	def_bool X86_64
927	prompt "HPET Timer Support" if X86_32
928	help
929	  Use the IA-PC HPET (High Precision Event Timer) to manage
930	  time in preference to the PIT and RTC, if a HPET is
931	  present.
932	  HPET is the next generation timer replacing legacy 8254s.
933	  The HPET provides a stable time base on SMP
934	  systems, unlike the TSC, but it is more expensive to access,
935	  as it is off-chip.  The interface used is documented
936	  in the HPET spec, revision 1.
937
938	  You can safely choose Y here.  However, HPET will only be
939	  activated if the platform and the BIOS support this feature.
940	  Otherwise the 8254 will be used for timing services.
941
942	  Choose N to continue using the legacy 8254 timer.
943
944config HPET_EMULATE_RTC
945	def_bool y
946	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
947
948# Mark as expert because too many people got it wrong.
949# The code disables itself when not needed.
950config DMI
951	default y
952	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
953	bool "Enable DMI scanning" if EXPERT
954	help
955	  Enabled scanning of DMI to identify machine quirks. Say Y
956	  here unless you have verified that your setup is not
957	  affected by entries in the DMI blacklist. Required by PNP
958	  BIOS code.
959
960config GART_IOMMU
961	bool "Old AMD GART IOMMU support"
962	select IOMMU_HELPER
963	select SWIOTLB
964	depends on X86_64 && PCI && AMD_NB
965	help
966	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
967	  GART based hardware IOMMUs.
968
969	  The GART supports full DMA access for devices with 32-bit access
970	  limitations, on systems with more than 3 GB. This is usually needed
971	  for USB, sound, many IDE/SATA chipsets and some other devices.
972
973	  Newer systems typically have a modern AMD IOMMU, supported via
974	  the CONFIG_AMD_IOMMU=y config option.
975
976	  In normal configurations this driver is only active when needed:
977	  there's more than 3 GB of memory and the system contains a
978	  32-bit limited device.
979
980	  If unsure, say Y.
981
982config BOOT_VESA_SUPPORT
983	bool
984	help
985	  If true, at least one selected framebuffer driver can take advantage
986	  of VESA video modes set at an early boot stage via the vga= parameter.
987
988config MAXSMP
989	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
990	depends on X86_64 && SMP && DEBUG_KERNEL
991	select CPUMASK_OFFSTACK
992	help
993	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
994	  If unsure, say N.
995
996#
997# The maximum number of CPUs supported:
998#
999# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
1000# and which can be configured interactively in the
1001# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
1002#
1003# The ranges are different on 32-bit and 64-bit kernels, depending on
1004# hardware capabilities and scalability features of the kernel.
1005#
1006# ( If MAXSMP is enabled we just use the highest possible value and disable
1007#   interactive configuration. )
1008#
1009
1010config NR_CPUS_RANGE_BEGIN
1011	int
1012	default NR_CPUS_RANGE_END if MAXSMP
1013	default    1 if !SMP
1014	default    2
1015
1016config NR_CPUS_RANGE_END
1017	int
1018	depends on X86_32
1019	default    8 if  SMP
1020	default    1 if !SMP
1021
1022config NR_CPUS_RANGE_END
1023	int
1024	depends on X86_64
1025	default 8192 if  SMP && CPUMASK_OFFSTACK
1026	default  512 if  SMP && !CPUMASK_OFFSTACK
1027	default    1 if !SMP
1028
1029config NR_CPUS_DEFAULT
1030	int
1031	depends on X86_32
1032	default    8 if  SMP
1033	default    1 if !SMP
1034
1035config NR_CPUS_DEFAULT
1036	int
1037	depends on X86_64
1038	default 8192 if  MAXSMP
1039	default   64 if  SMP
1040	default    1 if !SMP
1041
1042config NR_CPUS
1043	int "Maximum number of CPUs" if SMP && !MAXSMP
1044	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1045	default NR_CPUS_DEFAULT
1046	help
1047	  This allows you to specify the maximum number of CPUs which this
1048	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1049	  supported value is 8192, otherwise the maximum value is 512.  The
1050	  minimum value which makes sense is 2.
1051
1052	  This is purely to save memory: each supported CPU adds about 8KB
1053	  to the kernel image.
1054
1055config SCHED_MC_PRIO
1056	bool "CPU core priorities scheduler support"
1057	depends on SCHED_MC
1058	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1059	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1060	select CPU_FREQ
1061	default y
1062	help
1063	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1064	  core ordering determined at manufacturing time, which allows
1065	  certain cores to reach higher turbo frequencies (when running
1066	  single threaded workloads) than others.
1067
1068	  Enabling this kernel feature teaches the scheduler about
1069	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1070	  scheduler's CPU selection logic accordingly, so that higher
1071	  overall system performance can be achieved.
1072
1073	  This feature will have no effect on CPUs without this feature.
1074
1075	  If unsure say Y here.
1076
1077config UP_LATE_INIT
1078	def_bool y
1079	depends on !SMP && X86_LOCAL_APIC
1080
1081config X86_UP_APIC
1082	bool "Local APIC support on uniprocessors" if !PCI_MSI
1083	default PCI_MSI
1084	depends on X86_32 && !SMP
1085	help
1086	  A local APIC (Advanced Programmable Interrupt Controller) is an
1087	  integrated interrupt controller in the CPU. If you have a single-CPU
1088	  system which has a processor with a local APIC, you can say Y here to
1089	  enable and use it. If you say Y here even though your machine doesn't
1090	  have a local APIC, then the kernel will still run with no slowdown at
1091	  all. The local APIC supports CPU-generated self-interrupts (timer,
1092	  performance counters), and the NMI watchdog which detects hard
1093	  lockups.
1094
1095config X86_UP_IOAPIC
1096	bool "IO-APIC support on uniprocessors"
1097	depends on X86_UP_APIC
1098	help
1099	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1100	  SMP-capable replacement for PC-style interrupt controllers. Most
1101	  SMP systems and many recent uniprocessor systems have one.
1102
1103	  If you have a single-CPU system with an IO-APIC, you can say Y here
1104	  to use it. If you say Y here even though your machine doesn't have
1105	  an IO-APIC, then the kernel will still run with no slowdown at all.
1106
1107config X86_LOCAL_APIC
1108	def_bool y
1109	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1110	select IRQ_DOMAIN_HIERARCHY
1111
1112config ACPI_MADT_WAKEUP
1113	def_bool y
1114	depends on X86_64
1115	depends on ACPI
1116	depends on SMP
1117	depends on X86_LOCAL_APIC
1118
1119config X86_IO_APIC
1120	def_bool y
1121	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1122
1123config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1124	bool "Reroute for broken boot IRQs"
1125	depends on X86_IO_APIC
1126	help
1127	  This option enables a workaround that fixes a source of
1128	  spurious interrupts. This is recommended when threaded
1129	  interrupt handling is used on systems where the generation of
1130	  superfluous "boot interrupts" cannot be disabled.
1131
1132	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1133	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1134	  kernel does during interrupt handling). On chipsets where this
1135	  boot IRQ generation cannot be disabled, this workaround keeps
1136	  the original IRQ line masked so that only the equivalent "boot
1137	  IRQ" is delivered to the CPUs. The workaround also tells the
1138	  kernel to set up the IRQ handler on the boot IRQ line. In this
1139	  way only one interrupt is delivered to the kernel. Otherwise
1140	  the spurious second interrupt may cause the kernel to bring
1141	  down (vital) interrupt lines.
1142
1143	  Only affects "broken" chipsets. Interrupt sharing may be
1144	  increased on these systems.
1145
1146config X86_MCE
1147	bool "Machine Check / overheating reporting"
1148	select GENERIC_ALLOCATOR
1149	default y
1150	help
1151	  Machine Check support allows the processor to notify the
1152	  kernel if it detects a problem (e.g. overheating, data corruption).
1153	  The action the kernel takes depends on the severity of the problem,
1154	  ranging from warning messages to halting the machine.
1155
1156config X86_MCELOG_LEGACY
1157	bool "Support for deprecated /dev/mcelog character device"
1158	depends on X86_MCE
1159	help
1160	  Enable support for /dev/mcelog which is needed by the old mcelog
1161	  userspace logging daemon. Consider switching to the new generation
1162	  rasdaemon solution.
1163
1164config X86_MCE_INTEL
1165	def_bool y
1166	prompt "Intel MCE features"
1167	depends on X86_MCE && X86_LOCAL_APIC
1168	help
1169	  Additional support for intel specific MCE features such as
1170	  the thermal monitor.
1171
1172config X86_MCE_AMD
1173	def_bool y
1174	prompt "AMD MCE features"
1175	depends on X86_MCE && X86_LOCAL_APIC
1176	help
1177	  Additional support for AMD specific MCE features such as
1178	  the DRAM Error Threshold.
1179
1180config X86_ANCIENT_MCE
1181	bool "Support for old Pentium 5 / WinChip machine checks"
1182	depends on X86_32 && X86_MCE
1183	help
1184	  Include support for machine check handling on old Pentium 5 or WinChip
1185	  systems. These typically need to be enabled explicitly on the command
1186	  line.
1187
1188config X86_MCE_THRESHOLD
1189	depends on X86_MCE_AMD || X86_MCE_INTEL
1190	def_bool y
1191
1192config X86_MCE_INJECT
1193	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1194	tristate "Machine check injector support"
1195	help
1196	  Provide support for injecting machine checks for testing purposes.
1197	  If you don't know what a machine check is and you don't do kernel
1198	  QA it is safe to say n.
1199
1200source "arch/x86/events/Kconfig"
1201
1202config X86_LEGACY_VM86
1203	bool "Legacy VM86 support"
1204	depends on X86_32
1205	help
1206	  This option allows user programs to put the CPU into V8086
1207	  mode, which is an 80286-era approximation of 16-bit real mode.
1208
1209	  Some very old versions of X and/or vbetool require this option
1210	  for user mode setting.  Similarly, DOSEMU will use it if
1211	  available to accelerate real mode DOS programs.  However, any
1212	  recent version of DOSEMU, X, or vbetool should be fully
1213	  functional even without kernel VM86 support, as they will all
1214	  fall back to software emulation. Nevertheless, if you are using
1215	  a 16-bit DOS program where 16-bit performance matters, vm86
1216	  mode might be faster than emulation and you might want to
1217	  enable this option.
1218
1219	  Note that any app that works on a 64-bit kernel is unlikely to
1220	  need this option, as 64-bit kernels don't, and can't, support
1221	  V8086 mode. This option is also unrelated to 16-bit protected
1222	  mode and is not needed to run most 16-bit programs under Wine.
1223
1224	  Enabling this option increases the complexity of the kernel
1225	  and slows down exception handling a tiny bit.
1226
1227	  If unsure, say N here.
1228
1229config VM86
1230	bool
1231	default X86_LEGACY_VM86
1232
1233config X86_16BIT
1234	bool "Enable support for 16-bit segments" if EXPERT
1235	default y
1236	depends on MODIFY_LDT_SYSCALL
1237	help
1238	  This option is required by programs like Wine to run 16-bit
1239	  protected mode legacy code on x86 processors.  Disabling
1240	  this option saves about 300 bytes on i386, or around 6K text
1241	  plus 16K runtime memory on x86-64,
1242
1243config X86_ESPFIX32
1244	def_bool y
1245	depends on X86_16BIT && X86_32
1246
1247config X86_ESPFIX64
1248	def_bool y
1249	depends on X86_16BIT && X86_64
1250
1251config X86_VSYSCALL_EMULATION
1252	bool "Enable vsyscall emulation" if EXPERT
1253	default y
1254	depends on X86_64
1255	help
1256	  This enables emulation of the legacy vsyscall page.  Disabling
1257	  it is roughly equivalent to booting with vsyscall=none, except
1258	  that it will also disable the helpful warning if a program
1259	  tries to use a vsyscall.  With this option set to N, offending
1260	  programs will just segfault, citing addresses of the form
1261	  0xffffffffff600?00.
1262
1263	  This option is required by many programs built before 2013, and
1264	  care should be used even with newer programs if set to N.
1265
1266	  Disabling this option saves about 7K of kernel size and
1267	  possibly 4K of additional runtime pagetable memory.
1268
1269config X86_IOPL_IOPERM
1270	bool "IOPERM and IOPL Emulation"
1271	default y
1272	help
1273	  This enables the ioperm() and iopl() syscalls which are necessary
1274	  for legacy applications.
1275
1276	  Legacy IOPL support is an overbroad mechanism which allows user
1277	  space aside of accessing all 65536 I/O ports also to disable
1278	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1279	  capabilities and permission from potentially active security
1280	  modules.
1281
1282	  The emulation restricts the functionality of the syscall to
1283	  only allowing the full range I/O port access, but prevents the
1284	  ability to disable interrupts from user space which would be
1285	  granted if the hardware IOPL mechanism would be used.
1286
1287config TOSHIBA
1288	tristate "Toshiba Laptop support"
1289	depends on X86_32
1290	help
1291	  This adds a driver to safely access the System Management Mode of
1292	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1293	  not work on models with a Phoenix BIOS. The System Management Mode
1294	  is used to set the BIOS and power saving options on Toshiba portables.
1295
1296	  For information on utilities to make use of this driver see the
1297	  Toshiba Linux utilities web site at:
1298	  <http://www.buzzard.org.uk/toshiba/>.
1299
1300	  Say Y if you intend to run this kernel on a Toshiba portable.
1301	  Say N otherwise.
1302
1303config X86_REBOOTFIXUPS
1304	bool "Enable X86 board specific fixups for reboot"
1305	depends on X86_32
1306	help
1307	  This enables chipset and/or board specific fixups to be done
1308	  in order to get reboot to work correctly. This is only needed on
1309	  some combinations of hardware and BIOS. The symptom, for which
1310	  this config is intended, is when reboot ends with a stalled/hung
1311	  system.
1312
1313	  Currently, the only fixup is for the Geode machines using
1314	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1315
1316	  Say Y if you want to enable the fixup. Currently, it's safe to
1317	  enable this option even if you don't need it.
1318	  Say N otherwise.
1319
1320config MICROCODE
1321	def_bool y
1322	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1323	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1324
1325config MICROCODE_INITRD32
1326	def_bool y
1327	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1328
1329config MICROCODE_LATE_LOADING
1330	bool "Late microcode loading (DANGEROUS)"
1331	default n
1332	depends on MICROCODE && SMP
1333	help
1334	  Loading microcode late, when the system is up and executing instructions
1335	  is a tricky business and should be avoided if possible. Just the sequence
1336	  of synchronizing all cores and SMT threads is one fragile dance which does
1337	  not guarantee that cores might not softlock after the loading. Therefore,
1338	  use this at your own risk. Late loading taints the kernel unless the
1339	  microcode header indicates that it is safe for late loading via the
1340	  minimal revision check. This minimal revision check can be enforced on
1341	  the kernel command line with "microcode=force_minrev".
1342
1343config MICROCODE_LATE_FORCE_MINREV
1344	bool "Enforce late microcode loading minimal revision check"
1345	default n
1346	depends on MICROCODE_LATE_LOADING
1347	help
1348	  To prevent that users load microcode late which modifies already
1349	  in use features, newer microcode patches have a minimum revision field
1350	  in the microcode header, which tells the kernel which minimum
1351	  revision must be active in the CPU to safely load that new microcode
1352	  late into the running system. If disabled the check will not
1353	  be enforced but the kernel will be tainted when the minimal
1354	  revision check fails.
1355
1356	  This minimal revision check can also be controlled via the
1357	  "microcode=force_minrev" parameter on the kernel command line.
1358
1359	  If unsure say Y.
1360
1361config MICROCODE_DBG
1362	bool "Enable microcode loader debugging"
1363	default n
1364	depends on MICROCODE
1365	help
1366	  Enable code which allows for debugging the microcode loader in
1367	  a guest. Meaning the patch loading is simulated but everything else
1368	  related to patch parsing and handling is done as on baremetal with
1369	  the purpose of debugging solely the software side of things.
1370
1371	  You almost certainly want to say n here.
1372
1373config X86_MSR
1374	tristate "/dev/cpu/*/msr - Model-specific register support"
1375	help
1376	  This device gives privileged processes access to the x86
1377	  Model-Specific Registers (MSRs).  It is a character device with
1378	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1379	  MSR accesses are directed to a specific CPU on multi-processor
1380	  systems.
1381
1382config X86_CPUID
1383	tristate "/dev/cpu/*/cpuid - CPU information support"
1384	help
1385	  This device gives processes access to the x86 CPUID instruction to
1386	  be executed on a specific processor.  It is a character device
1387	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1388	  /dev/cpu/31/cpuid.
1389
1390config HIGHMEM4G
1391	bool "High Memory Support"
1392	depends on X86_32
1393	help
1394	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1395	  However, the address space of 32-bit x86 processors is only 4
1396	  Gigabytes large. That means that, if you have a large amount of
1397	  physical memory, not all of it can be "permanently mapped" by the
1398	  kernel. The physical memory that's not permanently mapped is called
1399	  "high memory".
1400
1401	  If you are compiling a kernel which will never run on a machine with
1402	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1403	  choice and suitable for most users). This will result in a "3GB/1GB"
1404	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1405	  space and the remaining part of the 4GB virtual memory space is used
1406	  by the kernel to permanently map as much physical memory as
1407	  possible.
1408
1409	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1410	  answer "Y" here.
1411
1412	  If unsure, say N.
1413
1414choice
1415	prompt "Memory split" if EXPERT
1416	default VMSPLIT_3G
1417	depends on X86_32
1418	help
1419	  Select the desired split between kernel and user memory.
1420
1421	  If the address range available to the kernel is less than the
1422	  physical memory installed, the remaining memory will be available
1423	  as "high memory". Accessing high memory is a little more costly
1424	  than low memory, as it needs to be mapped into the kernel first.
1425	  Note that increasing the kernel address space limits the range
1426	  available to user programs, making the address space there
1427	  tighter.  Selecting anything other than the default 3G/1G split
1428	  will also likely make your kernel incompatible with binary-only
1429	  kernel modules.
1430
1431	  If you are not absolutely sure what you are doing, leave this
1432	  option alone!
1433
1434	config VMSPLIT_3G
1435		bool "3G/1G user/kernel split"
1436	config VMSPLIT_3G_OPT
1437		depends on !X86_PAE
1438		bool "3G/1G user/kernel split (for full 1G low memory)"
1439	config VMSPLIT_2G
1440		bool "2G/2G user/kernel split"
1441	config VMSPLIT_2G_OPT
1442		depends on !X86_PAE
1443		bool "2G/2G user/kernel split (for full 2G low memory)"
1444	config VMSPLIT_1G
1445		bool "1G/3G user/kernel split"
1446endchoice
1447
1448config PAGE_OFFSET
1449	hex
1450	default 0xB0000000 if VMSPLIT_3G_OPT
1451	default 0x80000000 if VMSPLIT_2G
1452	default 0x78000000 if VMSPLIT_2G_OPT
1453	default 0x40000000 if VMSPLIT_1G
1454	default 0xC0000000
1455	depends on X86_32
1456
1457config HIGHMEM
1458	def_bool HIGHMEM4G
1459
1460config X86_PAE
1461	bool "PAE (Physical Address Extension) Support"
1462	depends on X86_32 && X86_HAVE_PAE
1463	select PHYS_ADDR_T_64BIT
1464	help
1465	  PAE is required for NX support, and furthermore enables
1466	  larger swapspace support for non-overcommit purposes. It
1467	  has the cost of more pagetable lookup overhead, and also
1468	  consumes more pagetable space per process.
1469
1470config X86_DIRECT_GBPAGES
1471	def_bool y
1472	depends on X86_64
1473	help
1474	  Certain kernel features effectively disable kernel
1475	  linear 1 GB mappings (even if the CPU otherwise
1476	  supports them), so don't confuse the user by printing
1477	  that we have them enabled.
1478
1479config X86_CPA_STATISTICS
1480	bool "Enable statistic for Change Page Attribute"
1481	depends on DEBUG_FS
1482	help
1483	  Expose statistics about the Change Page Attribute mechanism, which
1484	  helps to determine the effectiveness of preserving large and huge
1485	  page mappings when mapping protections are changed.
1486
1487config X86_MEM_ENCRYPT
1488	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1489	select DYNAMIC_PHYSICAL_MASK
1490	def_bool n
1491
1492config AMD_MEM_ENCRYPT
1493	bool "AMD Secure Memory Encryption (SME) support"
1494	depends on X86_64 && CPU_SUP_AMD
1495	depends on EFI_STUB
1496	select DMA_COHERENT_POOL
1497	select ARCH_USE_MEMREMAP_PROT
1498	select INSTRUCTION_DECODER
1499	select ARCH_HAS_CC_PLATFORM
1500	select X86_MEM_ENCRYPT
1501	select UNACCEPTED_MEMORY
1502	select CRYPTO_LIB_AESGCM
1503	help
1504	  Say yes to enable support for the encryption of system memory.
1505	  This requires an AMD processor that supports Secure Memory
1506	  Encryption (SME).
1507
1508# Common NUMA Features
1509config NUMA
1510	bool "NUMA Memory Allocation and Scheduler Support"
1511	depends on SMP
1512	depends on X86_64
1513	select USE_PERCPU_NUMA_NODE_ID
1514	select OF_NUMA if OF
1515	help
1516	  Enable NUMA (Non-Uniform Memory Access) support.
1517
1518	  The kernel will try to allocate memory used by a CPU on the
1519	  local memory controller of the CPU and add some more
1520	  NUMA awareness to the kernel.
1521
1522	  For 64-bit this is recommended if the system is Intel Core i7
1523	  (or later), AMD Opteron, or EM64T NUMA.
1524
1525	  Otherwise, you should say N.
1526
1527config AMD_NUMA
1528	def_bool y
1529	prompt "Old style AMD Opteron NUMA detection"
1530	depends on X86_64 && NUMA && PCI
1531	help
1532	  Enable AMD NUMA node topology detection.  You should say Y here if
1533	  you have a multi processor AMD system. This uses an old method to
1534	  read the NUMA configuration directly from the builtin Northbridge
1535	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1536	  which also takes priority if both are compiled in.
1537
1538config X86_64_ACPI_NUMA
1539	def_bool y
1540	prompt "ACPI NUMA detection"
1541	depends on X86_64 && NUMA && ACPI && PCI
1542	select ACPI_NUMA
1543	help
1544	  Enable ACPI SRAT based node topology detection.
1545
1546config NODES_SHIFT
1547	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1548	range 1 10
1549	default "10" if MAXSMP
1550	default "6" if X86_64
1551	default "3"
1552	depends on NUMA
1553	help
1554	  Specify the maximum number of NUMA Nodes available on the target
1555	  system.  Increases memory reserved to accommodate various tables.
1556
1557config ARCH_FLATMEM_ENABLE
1558	def_bool y
1559	depends on X86_32 && !NUMA
1560
1561config ARCH_SPARSEMEM_ENABLE
1562	def_bool y
1563	select SPARSEMEM_STATIC if X86_32
1564	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1565
1566config ARCH_SPARSEMEM_DEFAULT
1567	def_bool X86_64 || (NUMA && X86_32)
1568
1569config ARCH_SELECT_MEMORY_MODEL
1570	def_bool y
1571	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1572
1573config ARCH_MEMORY_PROBE
1574	bool "Enable sysfs memory/probe interface"
1575	depends on MEMORY_HOTPLUG
1576	help
1577	  This option enables a sysfs memory/probe interface for testing.
1578	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1579	  If you are unsure how to answer this question, answer N.
1580
1581config ARCH_PROC_KCORE_TEXT
1582	def_bool y
1583	depends on X86_64 && PROC_KCORE
1584
1585config ILLEGAL_POINTER_VALUE
1586	hex
1587	default 0 if X86_32
1588	default 0xdead000000000000 if X86_64
1589
1590config X86_PMEM_LEGACY_DEVICE
1591	bool
1592
1593config X86_PMEM_LEGACY
1594	tristate "Support non-standard NVDIMMs and ADR protected memory"
1595	depends on PHYS_ADDR_T_64BIT
1596	depends on BLK_DEV
1597	select X86_PMEM_LEGACY_DEVICE
1598	select NUMA_KEEP_MEMINFO if NUMA
1599	select LIBNVDIMM
1600	help
1601	  Treat memory marked using the non-standard e820 type of 12 as used
1602	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1603	  The kernel will offer these regions to the 'pmem' driver so
1604	  they can be used for persistent storage.
1605
1606	  Say Y if unsure.
1607
1608config X86_CHECK_BIOS_CORRUPTION
1609	bool "Check for low memory corruption"
1610	help
1611	  Periodically check for memory corruption in low memory, which
1612	  is suspected to be caused by BIOS.  Even when enabled in the
1613	  configuration, it is disabled at runtime.  Enable it by
1614	  setting "memory_corruption_check=1" on the kernel command
1615	  line.  By default it scans the low 64k of memory every 60
1616	  seconds; see the memory_corruption_check_size and
1617	  memory_corruption_check_period parameters in
1618	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1619
1620	  When enabled with the default parameters, this option has
1621	  almost no overhead, as it reserves a relatively small amount
1622	  of memory and scans it infrequently.  It both detects corruption
1623	  and prevents it from affecting the running system.
1624
1625	  It is, however, intended as a diagnostic tool; if repeatable
1626	  BIOS-originated corruption always affects the same memory,
1627	  you can use memmap= to prevent the kernel from using that
1628	  memory.
1629
1630config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1631	bool "Set the default setting of memory_corruption_check"
1632	depends on X86_CHECK_BIOS_CORRUPTION
1633	default y
1634	help
1635	  Set whether the default state of memory_corruption_check is
1636	  on or off.
1637
1638config MATH_EMULATION
1639	bool
1640	depends on MODIFY_LDT_SYSCALL
1641	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1642	help
1643	  Linux can emulate a math coprocessor (used for floating point
1644	  operations) if you don't have one. 486DX and Pentium processors have
1645	  a math coprocessor built in, 486SX and 386 do not, unless you added
1646	  a 487DX or 387, respectively. (The messages during boot time can
1647	  give you some hints here ["man dmesg"].) Everyone needs either a
1648	  coprocessor or this emulation.
1649
1650	  If you don't have a math coprocessor, you need to say Y here; if you
1651	  say Y here even though you have a coprocessor, the coprocessor will
1652	  be used nevertheless. (This behavior can be changed with the kernel
1653	  command line option "no387", which comes handy if your coprocessor
1654	  is broken. Try "man bootparam" or see the documentation of your boot
1655	  loader (lilo or loadlin) about how to pass options to the kernel at
1656	  boot time.) This means that it is a good idea to say Y here if you
1657	  intend to use this kernel on different machines.
1658
1659	  More information about the internals of the Linux math coprocessor
1660	  emulation can be found in <file:arch/x86/math-emu/README>.
1661
1662	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1663	  kernel, it won't hurt.
1664
1665config MTRR
1666	def_bool y
1667	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1668	help
1669	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1670	  the Memory Type Range Registers (MTRRs) may be used to control
1671	  processor access to memory ranges. This is most useful if you have
1672	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1673	  allows bus write transfers to be combined into a larger transfer
1674	  before bursting over the PCI/AGP bus. This can increase performance
1675	  of image write operations 2.5 times or more. Saying Y here creates a
1676	  /proc/mtrr file which may be used to manipulate your processor's
1677	  MTRRs. Typically the X server should use this.
1678
1679	  This code has a reasonably generic interface so that similar
1680	  control registers on other processors can be easily supported
1681	  as well:
1682
1683	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1684	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1685	  these, the ARRs are used to emulate the MTRRs.
1686	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1687	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1688	  write-combining. All of these processors are supported by this code
1689	  and it makes sense to say Y here if you have one of them.
1690
1691	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1692	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1693	  can lead to all sorts of problems, so it's good to say Y here.
1694
1695	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1696	  just add about 9 KB to your kernel.
1697
1698	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1699
1700config MTRR_SANITIZER
1701	def_bool y
1702	prompt "MTRR cleanup support"
1703	depends on MTRR
1704	help
1705	  Convert MTRR layout from continuous to discrete, so X drivers can
1706	  add writeback entries.
1707
1708	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1709	  The largest mtrr entry size for a continuous block can be set with
1710	  mtrr_chunk_size.
1711
1712	  If unsure, say Y.
1713
1714config MTRR_SANITIZER_ENABLE_DEFAULT
1715	int "MTRR cleanup enable value (0-1)"
1716	range 0 1
1717	default "0"
1718	depends on MTRR_SANITIZER
1719	help
1720	  Enable mtrr cleanup default value
1721
1722config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1723	int "MTRR cleanup spare reg num (0-7)"
1724	range 0 7
1725	default "1"
1726	depends on MTRR_SANITIZER
1727	help
1728	  mtrr cleanup spare entries default, it can be changed via
1729	  mtrr_spare_reg_nr=N on the kernel command line.
1730
1731config X86_PAT
1732	def_bool y
1733	prompt "x86 PAT support" if EXPERT
1734	depends on MTRR
1735	select ARCH_USES_PG_ARCH_2
1736	help
1737	  Use PAT attributes to setup page level cache control.
1738
1739	  PATs are the modern equivalents of MTRRs and are much more
1740	  flexible than MTRRs.
1741
1742	  Say N here if you see bootup problems (boot crash, boot hang,
1743	  spontaneous reboots) or a non-working video driver.
1744
1745	  If unsure, say Y.
1746
1747config X86_UMIP
1748	def_bool y
1749	prompt "User Mode Instruction Prevention" if EXPERT
1750	help
1751	  User Mode Instruction Prevention (UMIP) is a security feature in
1752	  some x86 processors. If enabled, a general protection fault is
1753	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1754	  executed in user mode. These instructions unnecessarily expose
1755	  information about the hardware state.
1756
1757	  The vast majority of applications do not use these instructions.
1758	  For the very few that do, software emulation is provided in
1759	  specific cases in protected and virtual-8086 modes. Emulated
1760	  results are dummy.
1761
1762config CC_HAS_IBT
1763	# GCC >= 9 and binutils >= 2.29
1764	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1765	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || CC_IS_CLANG) && \
1766		  $(as-instr,endbr64)
1767
1768config X86_CET
1769	def_bool n
1770	help
1771	  CET features configured (Shadow stack or IBT)
1772
1773config X86_KERNEL_IBT
1774	prompt "Indirect Branch Tracking"
1775	def_bool y
1776	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1777	select OBJTOOL
1778	select X86_CET
1779	help
1780	  Build the kernel with support for Indirect Branch Tracking, a
1781	  hardware support course-grain forward-edge Control Flow Integrity
1782	  protection. It enforces that all indirect calls must land on
1783	  an ENDBR instruction, as such, the compiler will instrument the
1784	  code with them to make this happen.
1785
1786	  In addition to building the kernel with IBT, seal all functions that
1787	  are not indirect call targets, avoiding them ever becoming one.
1788
1789	  This requires LTO like objtool runs and will slow down the build. It
1790	  does significantly reduce the number of ENDBR instructions in the
1791	  kernel image.
1792
1793config X86_INTEL_MEMORY_PROTECTION_KEYS
1794	prompt "Memory Protection Keys"
1795	def_bool y
1796	# Note: only available in 64-bit mode
1797	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1798	select ARCH_USES_HIGH_VMA_FLAGS
1799	select ARCH_HAS_PKEYS
1800	help
1801	  Memory Protection Keys provides a mechanism for enforcing
1802	  page-based protections, but without requiring modification of the
1803	  page tables when an application changes protection domains.
1804
1805	  For details, see Documentation/core-api/protection-keys.rst
1806
1807	  If unsure, say y.
1808
1809config ARCH_PKEY_BITS
1810	int
1811	default 4
1812
1813choice
1814	prompt "TSX enable mode"
1815	depends on CPU_SUP_INTEL
1816	default X86_INTEL_TSX_MODE_OFF
1817	help
1818	  Intel's TSX (Transactional Synchronization Extensions) feature
1819	  allows to optimize locking protocols through lock elision which
1820	  can lead to a noticeable performance boost.
1821
1822	  On the other hand it has been shown that TSX can be exploited
1823	  to form side channel attacks (e.g. TAA) and chances are there
1824	  will be more of those attacks discovered in the future.
1825
1826	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1827	  might override this decision by tsx=on the command line parameter.
1828	  Even with TSX enabled, the kernel will attempt to enable the best
1829	  possible TAA mitigation setting depending on the microcode available
1830	  for the particular machine.
1831
1832	  This option allows to set the default tsx mode between tsx=on, =off
1833	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1834	  details.
1835
1836	  Say off if not sure, auto if TSX is in use but it should be used on safe
1837	  platforms or on if TSX is in use and the security aspect of tsx is not
1838	  relevant.
1839
1840config X86_INTEL_TSX_MODE_OFF
1841	bool "off"
1842	help
1843	  TSX is disabled if possible - equals to tsx=off command line parameter.
1844
1845config X86_INTEL_TSX_MODE_ON
1846	bool "on"
1847	help
1848	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1849	  line parameter.
1850
1851config X86_INTEL_TSX_MODE_AUTO
1852	bool "auto"
1853	help
1854	  TSX is enabled on TSX capable HW that is believed to be safe against
1855	  side channel attacks- equals the tsx=auto command line parameter.
1856endchoice
1857
1858config X86_SGX
1859	bool "Software Guard eXtensions (SGX)"
1860	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1861	select CRYPTO_LIB_SHA256
1862	select MMU_NOTIFIER
1863	select NUMA_KEEP_MEMINFO if NUMA
1864	select XARRAY_MULTI
1865	help
1866	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1867	  that can be used by applications to set aside private regions of code
1868	  and data, referred to as enclaves. An enclave's private memory can
1869	  only be accessed by code running within the enclave. Accesses from
1870	  outside the enclave, including other enclaves, are disallowed by
1871	  hardware.
1872
1873	  If unsure, say N.
1874
1875config X86_USER_SHADOW_STACK
1876	bool "X86 userspace shadow stack"
1877	depends on AS_WRUSS
1878	depends on X86_64
1879	select ARCH_USES_HIGH_VMA_FLAGS
1880	select ARCH_HAS_USER_SHADOW_STACK
1881	select X86_CET
1882	help
1883	  Shadow stack protection is a hardware feature that detects function
1884	  return address corruption.  This helps mitigate ROP attacks.
1885	  Applications must be enabled to use it, and old userspace does not
1886	  get protection "for free".
1887
1888	  CPUs supporting shadow stacks were first released in 2020.
1889
1890	  See Documentation/arch/x86/shstk.rst for more information.
1891
1892	  If unsure, say N.
1893
1894config INTEL_TDX_HOST
1895	bool "Intel Trust Domain Extensions (TDX) host support"
1896	depends on CPU_SUP_INTEL
1897	depends on X86_64
1898	depends on KVM_INTEL
1899	depends on X86_X2APIC
1900	select ARCH_KEEP_MEMBLOCK
1901	depends on CONTIG_ALLOC
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
2402# except Kconfig can't do arithmetic :/
2403config FUNCTION_PADDING_BYTES
2404	int
2405	default FUNCTION_PADDING_CFI if CFI
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 && 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
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
2697config MITIGATION_TSA
2698	bool "Mitigate Transient Scheduler Attacks"
2699	depends on CPU_SUP_AMD
2700	default y
2701	help
2702	  Enable mitigation for Transient Scheduler Attacks. TSA is a hardware
2703	  security vulnerability on AMD CPUs which can lead to forwarding of
2704	  invalid info to subsequent instructions and thus can affect their
2705	  timing and thereby cause a leakage.
2706
2707config MITIGATION_VMSCAPE
2708	bool "Mitigate VMSCAPE"
2709	depends on KVM
2710	default y
2711	help
2712	  Enable mitigation for VMSCAPE attacks. VMSCAPE is a hardware security
2713	  vulnerability on Intel and AMD CPUs that may allow a guest to do
2714	  Spectre v2 style attacks on userspace hypervisor.
2715endif
2716
2717config ARCH_HAS_ADD_PAGES
2718	def_bool y
2719	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2720
2721menu "Power management and ACPI options"
2722
2723config ARCH_HIBERNATION_HEADER
2724	def_bool y
2725	depends on HIBERNATION
2726
2727source "kernel/power/Kconfig"
2728
2729source "drivers/acpi/Kconfig"
2730
2731config X86_APM_BOOT
2732	def_bool y
2733	depends on APM
2734
2735menuconfig APM
2736	tristate "APM (Advanced Power Management) BIOS support"
2737	depends on X86_32 && PM_SLEEP
2738	help
2739	  APM is a BIOS specification for saving power using several different
2740	  techniques. This is mostly useful for battery powered laptops with
2741	  APM compliant BIOSes. If you say Y here, the system time will be
2742	  reset after a RESUME operation, the /proc/apm device will provide
2743	  battery status information, and user-space programs will receive
2744	  notification of APM "events" (e.g. battery status change).
2745
2746	  If you select "Y" here, you can disable actual use of the APM
2747	  BIOS by passing the "apm=off" option to the kernel at boot time.
2748
2749	  Note that the APM support is almost completely disabled for
2750	  machines with more than one CPU.
2751
2752	  In order to use APM, you will need supporting software. For location
2753	  and more information, read <file:Documentation/power/apm-acpi.rst>
2754	  and the Battery Powered Linux mini-HOWTO, available from
2755	  <http://www.tldp.org/docs.html#howto>.
2756
2757	  This driver does not spin down disk drives (see the hdparm(8)
2758	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2759	  VESA-compliant "green" monitors.
2760
2761	  This driver does not support the TI 4000M TravelMate and the ACER
2762	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2763	  desktop machines also don't have compliant BIOSes, and this driver
2764	  may cause those machines to panic during the boot phase.
2765
2766	  Generally, if you don't have a battery in your machine, there isn't
2767	  much point in using this driver and you should say N. If you get
2768	  random kernel OOPSes or reboots that don't seem to be related to
2769	  anything, try disabling/enabling this option (or disabling/enabling
2770	  APM in your BIOS).
2771
2772	  Some other things you should try when experiencing seemingly random,
2773	  "weird" problems:
2774
2775	  1) make sure that you have enough swap space and that it is
2776	  enabled.
2777	  2) pass the "idle=poll" option to the kernel
2778	  3) switch on floating point emulation in the kernel and pass
2779	  the "no387" option to the kernel
2780	  4) pass the "floppy=nodma" option to the kernel
2781	  5) pass the "mem=4M" option to the kernel (thereby disabling
2782	  all but the first 4 MB of RAM)
2783	  6) make sure that the CPU is not over clocked.
2784	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2785	  8) disable the cache from your BIOS settings
2786	  9) install a fan for the video card or exchange video RAM
2787	  10) install a better fan for the CPU
2788	  11) exchange RAM chips
2789	  12) exchange the motherboard.
2790
2791	  To compile this driver as a module, choose M here: the
2792	  module will be called apm.
2793
2794if APM
2795
2796config APM_IGNORE_USER_SUSPEND
2797	bool "Ignore USER SUSPEND"
2798	help
2799	  This option will ignore USER SUSPEND requests. On machines with a
2800	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2801	  series notebooks, it is necessary to say Y because of a BIOS bug.
2802
2803config APM_DO_ENABLE
2804	bool "Enable PM at boot time"
2805	help
2806	  Enable APM features at boot time. From page 36 of the APM BIOS
2807	  specification: "When disabled, the APM BIOS does not automatically
2808	  power manage devices, enter the Standby State, enter the Suspend
2809	  State, or take power saving steps in response to CPU Idle calls."
2810	  This driver will make CPU Idle calls when Linux is idle (unless this
2811	  feature is turned off -- see "Do CPU IDLE calls", below). This
2812	  should always save battery power, but more complicated APM features
2813	  will be dependent on your BIOS implementation. You may need to turn
2814	  this option off if your computer hangs at boot time when using APM
2815	  support, or if it beeps continuously instead of suspending. Turn
2816	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2817	  T400CDT. This is off by default since most machines do fine without
2818	  this feature.
2819
2820config APM_CPU_IDLE
2821	depends on CPU_IDLE
2822	bool "Make CPU Idle calls when idle"
2823	help
2824	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2825	  On some machines, this can activate improved power savings, such as
2826	  a slowed CPU clock rate, when the machine is idle. These idle calls
2827	  are made after the idle loop has run for some length of time (e.g.,
2828	  333 mS). On some machines, this will cause a hang at boot time or
2829	  whenever the CPU becomes idle. (On machines with more than one CPU,
2830	  this option does nothing.)
2831
2832config APM_DISPLAY_BLANK
2833	bool "Enable console blanking using APM"
2834	help
2835	  Enable console blanking using the APM. Some laptops can use this to
2836	  turn off the LCD backlight when the screen blanker of the Linux
2837	  virtual console blanks the screen. Note that this is only used by
2838	  the virtual console screen blanker, and won't turn off the backlight
2839	  when using the X Window system. This also doesn't have anything to
2840	  do with your VESA-compliant power-saving monitor. Further, this
2841	  option doesn't work for all laptops -- it might not turn off your
2842	  backlight at all, or it might print a lot of errors to the console,
2843	  especially if you are using gpm.
2844
2845config APM_ALLOW_INTS
2846	bool "Allow interrupts during APM BIOS calls"
2847	help
2848	  Normally we disable external interrupts while we are making calls to
2849	  the APM BIOS as a measure to lessen the effects of a badly behaving
2850	  BIOS implementation.  The BIOS should reenable interrupts if it
2851	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2852	  many of the newer IBM Thinkpads.  If you experience hangs when you
2853	  suspend, try setting this to Y.  Otherwise, say N.
2854
2855endif # APM
2856
2857source "drivers/cpufreq/Kconfig"
2858
2859source "drivers/cpuidle/Kconfig"
2860
2861source "drivers/idle/Kconfig"
2862
2863endmenu
2864
2865menu "Bus options (PCI etc.)"
2866
2867choice
2868	prompt "PCI access mode"
2869	depends on X86_32 && PCI
2870	default PCI_GOANY
2871	help
2872	  On PCI systems, the BIOS can be used to detect the PCI devices and
2873	  determine their configuration. However, some old PCI motherboards
2874	  have BIOS bugs and may crash if this is done. Also, some embedded
2875	  PCI-based systems don't have any BIOS at all. Linux can also try to
2876	  detect the PCI hardware directly without using the BIOS.
2877
2878	  With this option, you can specify how Linux should detect the
2879	  PCI devices. If you choose "BIOS", the BIOS will be used,
2880	  if you choose "Direct", the BIOS won't be used, and if you
2881	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2882	  If you choose "Any", the kernel will try MMCONFIG, then the
2883	  direct access method and falls back to the BIOS if that doesn't
2884	  work. If unsure, go with the default, which is "Any".
2885
2886config PCI_GOBIOS
2887	bool "BIOS"
2888
2889config PCI_GOMMCONFIG
2890	bool "MMConfig"
2891
2892config PCI_GODIRECT
2893	bool "Direct"
2894
2895config PCI_GOOLPC
2896	bool "OLPC XO-1"
2897	depends on OLPC
2898
2899config PCI_GOANY
2900	bool "Any"
2901
2902endchoice
2903
2904config PCI_BIOS
2905	def_bool y
2906	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2907
2908# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2909config PCI_DIRECT
2910	def_bool y
2911	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2912
2913config PCI_MMCONFIG
2914	bool "Support mmconfig PCI config space access" if X86_64
2915	default y
2916	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2917	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2918	help
2919	  Add support for accessing the PCI configuration space as a memory
2920	  mapped area. It is the recommended method if the system supports
2921	  this (it must have PCI Express and ACPI for it to be available).
2922
2923	  In the unlikely case that enabling this configuration option causes
2924	  problems, the mechanism can be switched off with the 'pci=nommconf'
2925	  command line parameter.
2926
2927	  Say N only if you are sure that your platform does not support this
2928	  access method or you have problems caused by it.
2929
2930	  Say Y otherwise.
2931
2932config PCI_OLPC
2933	def_bool y
2934	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2935
2936config PCI_XEN
2937	def_bool y
2938	depends on PCI && XEN
2939
2940config MMCONF_FAM10H
2941	def_bool y
2942	depends on X86_64 && PCI_MMCONFIG && ACPI
2943
2944config PCI_CNB20LE_QUIRK
2945	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2946	depends on X86_32 && PCI
2947	help
2948	  Read the PCI windows out of the CNB20LE host bridge. This allows
2949	  PCI hotplug to work on systems with the CNB20LE chipset which do
2950	  not have ACPI.
2951
2952	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2953	  most probably only for Pentium III.
2954
2955	  To find out if you have such a chipset, search for a PCI device with
2956	  1166:0009 PCI IDs, for example by executing
2957		lspci -nn | grep '1166:0009'
2958	  The code is inactive if there is none.
2959
2960	  There's no public spec for this chipset, and this functionality
2961	  is known to be incomplete.
2962
2963	  You should say N unless you know you need this.
2964
2965config ISA_BUS
2966	bool "ISA bus support on modern systems" if EXPERT
2967	help
2968	  Expose ISA bus device drivers and options available for selection and
2969	  configuration. Enable this option if your target machine has an ISA
2970	  bus. ISA is an older system, displaced by PCI and newer bus
2971	  architectures -- if your target machine is modern, it probably does
2972	  not have an ISA bus.
2973
2974	  If unsure, say N.
2975
2976# x86_64 have no ISA slots, but can have ISA-style DMA.
2977config ISA_DMA_API
2978	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2979	default y
2980	help
2981	  Enables ISA-style DMA support for devices requiring such controllers.
2982	  If unsure, say Y.
2983
2984if X86_32
2985
2986config ISA
2987	bool "ISA support"
2988	help
2989	  Find out whether you have ISA slots on your motherboard.  ISA is the
2990	  name of a bus system, i.e. the way the CPU talks to the other stuff
2991	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2992	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2993	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2994
2995config SCx200
2996	tristate "NatSemi SCx200 support"
2997	help
2998	  This provides basic support for National Semiconductor's
2999	  (now AMD's) Geode processors.  The driver probes for the
3000	  PCI-IDs of several on-chip devices, so its a good dependency
3001	  for other scx200_* drivers.
3002
3003	  If compiled as a module, the driver is named scx200.
3004
3005config SCx200HR_TIMER
3006	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
3007	depends on SCx200
3008	default y
3009	help
3010	  This driver provides a clocksource built upon the on-chip
3011	  27MHz high-resolution timer.  Its also a workaround for
3012	  NSC Geode SC-1100's buggy TSC, which loses time when the
3013	  processor goes idle (as is done by the scheduler).  The
3014	  other workaround is idle=poll boot option.
3015
3016config OLPC
3017	bool "One Laptop Per Child support"
3018	depends on !X86_PAE
3019	select GPIOLIB
3020	select OF
3021	select OF_PROMTREE
3022	select IRQ_DOMAIN
3023	select OLPC_EC
3024	help
3025	  Add support for detecting the unique features of the OLPC
3026	  XO hardware.
3027
3028config OLPC_XO1_PM
3029	bool "OLPC XO-1 Power Management"
3030	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3031	help
3032	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3033
3034config OLPC_XO1_RTC
3035	bool "OLPC XO-1 Real Time Clock"
3036	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3037	help
3038	  Add support for the XO-1 real time clock, which can be used as a
3039	  programmable wakeup source.
3040
3041config OLPC_XO1_SCI
3042	bool "OLPC XO-1 SCI extras"
3043	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3044	depends on INPUT=y
3045	select POWER_SUPPLY
3046	help
3047	  Add support for SCI-based features of the OLPC XO-1 laptop:
3048	   - EC-driven system wakeups
3049	   - Power button
3050	   - Ebook switch
3051	   - Lid switch
3052	   - AC adapter status updates
3053	   - Battery status updates
3054
3055config OLPC_XO15_SCI
3056	bool "OLPC XO-1.5 SCI extras"
3057	depends on OLPC && ACPI
3058	select POWER_SUPPLY
3059	help
3060	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3061	   - EC-driven system wakeups
3062	   - AC adapter status updates
3063	   - Battery status updates
3064
3065config GEODE_COMMON
3066	bool
3067
3068config ALIX
3069	bool "PCEngines ALIX System Support (LED setup)"
3070	select GPIOLIB
3071	select GEODE_COMMON
3072	help
3073	  This option enables system support for the PCEngines ALIX.
3074	  At present this just sets up LEDs for GPIO control on
3075	  ALIX2/3/6 boards.  However, other system specific setup should
3076	  get added here.
3077
3078	  Note: You must still enable the drivers for GPIO and LED support
3079	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3080
3081	  Note: You have to set alix.force=1 for boards with Award BIOS.
3082
3083config NET5501
3084	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3085	select GPIOLIB
3086	select GEODE_COMMON
3087	help
3088	  This option enables system support for the Soekris Engineering net5501.
3089
3090config GEOS
3091	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3092	select GPIOLIB
3093	select GEODE_COMMON
3094	depends on DMI
3095	help
3096	  This option enables system support for the Traverse Technologies GEOS.
3097
3098config TS5500
3099	bool "Technologic Systems TS-5500 platform support"
3100	depends on MELAN
3101	select CHECK_SIGNATURE
3102	select NEW_LEDS
3103	select LEDS_CLASS
3104	help
3105	  This option enables system support for the Technologic Systems TS-5500.
3106
3107endif # X86_32
3108
3109config AMD_NB
3110	def_bool y
3111	depends on AMD_NODE
3112
3113config AMD_NODE
3114	def_bool y
3115	depends on CPU_SUP_AMD && PCI
3116
3117endmenu
3118
3119menu "Binary Emulations"
3120
3121config IA32_EMULATION
3122	bool "IA32 Emulation"
3123	depends on X86_64
3124	select ARCH_WANT_OLD_COMPAT_IPC
3125	select BINFMT_ELF
3126	select COMPAT_OLD_SIGACTION
3127	help
3128	  Include code to run legacy 32-bit programs under a
3129	  64-bit kernel. You should likely turn this on, unless you're
3130	  100% sure that you don't have any 32-bit programs left.
3131
3132config IA32_EMULATION_DEFAULT_DISABLED
3133	bool "IA32 emulation disabled by default"
3134	default n
3135	depends on IA32_EMULATION
3136	help
3137	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3138	  processes and access to 32-bit syscalls. If unsure, leave it to its
3139	  default value.
3140
3141config X86_X32_ABI
3142	bool "x32 ABI for 64-bit mode"
3143	depends on X86_64
3144	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3145	# compressed debug sections to x86_x32 properly:
3146	# https://github.com/ClangBuiltLinux/linux/issues/514
3147	# https://github.com/ClangBuiltLinux/linux/issues/1141
3148	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3149	help
3150	  Include code to run binaries for the x32 native 32-bit ABI
3151	  for 64-bit processors.  An x32 process gets access to the
3152	  full 64-bit register file and wide data path while leaving
3153	  pointers at 32 bits for smaller memory footprint.
3154
3155config COMPAT_32
3156	def_bool y
3157	depends on IA32_EMULATION || X86_32
3158	select HAVE_UID16
3159	select OLD_SIGSUSPEND3
3160
3161config COMPAT
3162	def_bool y
3163	depends on IA32_EMULATION || X86_X32_ABI
3164
3165config COMPAT_FOR_U64_ALIGNMENT
3166	def_bool y
3167	depends on COMPAT
3168
3169endmenu
3170
3171config HAVE_ATOMIC_IOMAP
3172	def_bool y
3173	depends on X86_32
3174
3175source "arch/x86/kvm/Kconfig"
3176
3177source "arch/x86/Kconfig.cpufeatures"
3178
3179source "arch/x86/Kconfig.assembler"
3180