xref: /linux/arch/x86/Kconfig (revision ff5ccdb8d5bd242f1064c6f7996603e47e28d095)
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_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
73	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
74	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
75	select ARCH_HAS_CPU_ATTACK_VECTORS	if CPU_MITIGATIONS
76	select ARCH_HAS_CACHE_LINE_SIZE
77	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
78	select ARCH_HAS_CPU_FINALIZE_INIT
79	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
80	select ARCH_HAS_CURRENT_STACK_POINTER
81	select ARCH_HAS_DEBUG_VIRTUAL
82	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
83	select ARCH_HAS_DEVMEM_IS_ALLOWED
84	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
85	select ARCH_HAS_EARLY_DEBUG		if KGDB
86	select ARCH_HAS_ELF_RANDOMIZE
87	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
88	select ARCH_HAS_FAST_MULTIPLIER
89	select ARCH_HAS_FORTIFY_SOURCE
90	select ARCH_HAS_GCOV_PROFILE_ALL
91	select ARCH_HAS_KCOV			if X86_64
92	select ARCH_HAS_KERNEL_FPU_SUPPORT
93	select ARCH_HAS_MEM_ENCRYPT
94	select ARCH_HAS_MEMBARRIER_SYNC_CORE
95	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
96	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
97	select ARCH_HAS_PMEM_API		if X86_64
98	select ARCH_HAS_PREEMPT_LAZY
99	select ARCH_HAS_PTDUMP
100	select ARCH_HAS_PTE_SPECIAL
101	select ARCH_HAS_HW_PTE_YOUNG
102	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
103	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
104	select ARCH_HAS_COPY_MC			if X86_64
105	select ARCH_HAS_SET_MEMORY
106	select ARCH_HAS_SET_DIRECT_MAP
107	select ARCH_HAS_STRICT_KERNEL_RWX
108	select ARCH_HAS_STRICT_MODULE_RWX
109	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
110	select ARCH_HAS_SYSCALL_WRAPPER
111	select ARCH_HAS_UBSAN
112	select ARCH_HAS_DEBUG_WX
113	select ARCH_HAS_ZONE_DMA_SET if EXPERT
114	select ARCH_HAVE_NMI_SAFE_CMPXCHG
115	select ARCH_HAVE_EXTRA_ELF_NOTES
116	select ARCH_MEMORY_ORDER_TSO
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_USE_BUILTIN_BSWAP
135	select ARCH_USE_CMPXCHG_LOCKREF
136	select ARCH_USE_MEMTEST
137	select ARCH_USE_QUEUED_RWLOCKS
138	select ARCH_USE_QUEUED_SPINLOCKS
139	select ARCH_USE_SYM_ANNOTATIONS
140	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
141	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
142	select ARCH_WANTS_CLOCKSOURCE_READ_INLINE	if X86_64
143	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
144	select ARCH_WANTS_NO_INSTR
145	select ARCH_WANT_GENERAL_HUGETLB
146	select ARCH_WANT_HUGE_PMD_SHARE		if X86_64
147	select ARCH_WANT_LD_ORPHAN_WARN
148	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
149	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
150	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
151	select ARCH_WANTS_THP_SWAP		if X86_64
152	select ARCH_HAS_PARANOID_L1D_FLUSH
153	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
154	select BUILDTIME_TABLE_SORT
155	select CLKEVT_I8253
156	select CLOCKSOURCE_WATCHDOG
157	# Word-size accesses may read uninitialized data past the trailing \0
158	# in strings and cause false KMSAN reports.
159	select DCACHE_WORD_ACCESS		if !KMSAN
160	select DYNAMIC_SIGFRAME
161	select EDAC_ATOMIC_SCRUB
162	select EDAC_SUPPORT
163	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
164	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
165	select GENERIC_CLOCKEVENTS_COUPLED_INLINE	if X86_64
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_GETTIMEOFDAY
183	select GENERIC_VDSO_OVERFLOW_PROTECT
184	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
185	select HARDIRQS_SW_RESEND
186	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
187	select HAS_IOPORT
188	select HAVE_ACPI_APEI			if ACPI
189	select HAVE_ACPI_APEI_NMI		if ACPI
190	select HAVE_ALIGNED_STRUCT_PAGE
191	select HAVE_ARCH_AUDITSYSCALL
192	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
193	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
194	select HAVE_ARCH_JUMP_LABEL
195	select HAVE_ARCH_JUMP_LABEL_RELATIVE
196	select HAVE_ARCH_KASAN			if X86_64
197	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
198	select HAVE_ARCH_KFENCE
199	select HAVE_ARCH_KMSAN			if X86_64
200	select HAVE_ARCH_KGDB
201	select HAVE_ARCH_KSTACK_ERASE
202	select HAVE_ARCH_MMAP_RND_BITS		if MMU
203	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
204	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
205	select HAVE_ARCH_PREL32_RELOCATIONS
206	select HAVE_ARCH_SECCOMP_FILTER
207	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
208	select HAVE_ARCH_TRACEHOOK
209	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
210	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
211	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
212	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
213	select HAVE_ARCH_VMAP_STACK		if X86_64
214	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
215	select HAVE_ARCH_WITHIN_STACK_FRAMES
216	select HAVE_ASM_MODVERSIONS
217	select HAVE_CMPXCHG_DOUBLE
218	select HAVE_CMPXCHG_LOCAL
219	select HAVE_CONTEXT_TRACKING_USER		if X86_64
220	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
221	select HAVE_C_RECORDMCOUNT
222	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
223	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
224	select HAVE_BUILDTIME_MCOUNT_SORT
225	select HAVE_DEBUG_KMEMLEAK
226	select HAVE_DMA_CONTIGUOUS
227	select HAVE_DYNAMIC_FTRACE
228	select HAVE_DYNAMIC_FTRACE_WITH_REGS
229	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
230	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
231	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
232	select HAVE_DYNAMIC_FTRACE_WITH_JMP	if X86_64
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_FUTEX_ROBUST_UNLOCK
240	select HAVE_GENERIC_TIF_BITS
241	select HAVE_GUP_FAST
242	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
243	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
244	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
245	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
246	select HAVE_FUNCTION_TRACER
247	select HAVE_GCC_PLUGINS
248	select HAVE_HW_BREAKPOINT
249	select HAVE_IOREMAP_PROT
250	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
251	select HAVE_IRQ_TIME_ACCOUNTING
252	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
253	select HAVE_KERNEL_BZIP2
254	select HAVE_KERNEL_GZIP
255	select HAVE_KERNEL_LZ4
256	select HAVE_KERNEL_LZMA
257	select HAVE_KERNEL_LZO
258	select HAVE_KERNEL_XZ
259	select HAVE_KERNEL_ZSTD
260	select HAVE_KPROBES
261	select HAVE_KPROBES_ON_FTRACE
262	select HAVE_FUNCTION_ERROR_INJECTION
263	select HAVE_KRETPROBES
264	select HAVE_RETHOOK
265	select HAVE_KLP_BUILD			if X86_64
266	select HAVE_LIVEPATCH			if X86_64
267	select HAVE_MIXED_BREAKPOINTS_REGS
268	select HAVE_MOD_ARCH_SPECIFIC
269	select HAVE_MOVE_PMD
270	select HAVE_MOVE_PUD
271	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
272	select HAVE_NMI
273	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
274	select HAVE_OBJTOOL			if X86_64
275	select HAVE_OPTPROBES
276	select HAVE_PAGE_SIZE_4KB
277	select HAVE_PCSPKR_PLATFORM
278	select HAVE_PERF_EVENTS
279	select HAVE_PERF_EVENTS_NMI
280	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
281	select HAVE_PCI
282	select HAVE_PERF_REGS
283	select HAVE_PERF_USER_STACK_DUMP
284	select ASYNC_KERNEL_PGTABLE_FREE	if IOMMU_SVA
285	select MMU_GATHER_RCU_TABLE_FREE
286	select MMU_GATHER_MERGE_VMAS
287	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
288	select HAVE_REGS_AND_STACK_ACCESS_API
289	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
290	select HAVE_FUNCTION_ARG_ACCESS_API
291	select HAVE_SETUP_PER_CPU_AREA
292	select HAVE_SOFTIRQ_ON_OWN_STACK
293	select HAVE_STACKPROTECTOR
294	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
295	select HAVE_STATIC_CALL
296	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
297	select HAVE_PREEMPT_DYNAMIC_CALL
298	select HAVE_RSEQ
299	select HAVE_RUST			if X86_64
300	select HAVE_SYSCALL_TRACEPOINTS
301	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
302	select HAVE_UNSTABLE_SCHED_CLOCK
303	select HAVE_UNWIND_USER_FP		if X86_64
304	select HAVE_USER_RETURN_NOTIFIER
305	select HAVE_GENERIC_VDSO
306	select VDSO_GETRANDOM			if X86_64
307	select HOTPLUG_PARALLEL			if SMP && X86_64
308	select HOTPLUG_SMT			if SMP
309	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
310	select IRQ_FORCED_THREADING
311	select LOCK_MM_AND_FIND_VMA
312	select NEED_PER_CPU_EMBED_FIRST_CHUNK
313	select NEED_PER_CPU_PAGE_FIRST_CHUNK
314	select NEED_SG_DMA_LENGTH
315	select NUMA_MEMBLKS			if NUMA
316	select PCI_DOMAINS			if PCI
317	select PCI_LOCKLESS_CONFIG		if PCI
318	select PERF_EVENTS
319	select RTC_LIB
320	select RTC_MC146818_LIB
321	select SPARSE_IRQ
322	select SYSCTL_EXCEPTION_TRACE
323	select THREAD_INFO_IN_TASK
324	select TRACE_IRQFLAGS_SUPPORT
325	select TRACE_IRQFLAGS_NMI_SUPPORT
326	select USER_STACKTRACE_SUPPORT
327	select HAVE_ARCH_KCSAN			if X86_64
328	select PROC_PID_ARCH_STATUS		if PROC_FS
329	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
330	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
331	select FUNCTION_ALIGNMENT_4B
332	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
333	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
334	select ARCH_SUPPORTS_SCHED_SMT		if SMP
335	select SCHED_SMT			if SMP
336	select ARCH_SUPPORTS_SCHED_CLUSTER	if SMP
337	select ARCH_SUPPORTS_SCHED_MC		if SMP
338	select HAVE_SINGLE_FTRACE_DIRECT_OPS	if X86_64 && DYNAMIC_FTRACE_WITH_DIRECT_CALLS
339
340config INSTRUCTION_DECODER
341	def_bool y
342	depends on KPROBES || PERF_EVENTS || UPROBES
343
344config OUTPUT_FORMAT
345	string
346	default "elf32-i386" if X86_32
347	default "elf64-x86-64" if X86_64
348
349config LOCKDEP_SUPPORT
350	def_bool y
351
352config STACKTRACE_SUPPORT
353	def_bool y
354
355config MMU
356	def_bool y
357
358config ARCH_MMAP_RND_BITS_MIN
359	default 28 if 64BIT
360	default 8
361
362config ARCH_MMAP_RND_BITS_MAX
363	default 32 if 64BIT
364	default 16
365
366config ARCH_MMAP_RND_COMPAT_BITS_MIN
367	default 8
368
369config ARCH_MMAP_RND_COMPAT_BITS_MAX
370	default 16
371
372config SBUS
373	bool
374
375config GENERIC_ISA_DMA
376	def_bool y
377	depends on ISA_DMA_API
378
379config GENERIC_CSUM
380	bool
381	default y if KMSAN || KASAN
382
383config GENERIC_BUG
384	def_bool y
385	depends on BUG
386	select GENERIC_BUG_RELATIVE_POINTERS
387
388config GENERIC_BUG_RELATIVE_POINTERS
389	bool
390
391config ARCH_MAY_HAVE_PC_FDC
392	def_bool y
393	depends on ISA_DMA_API
394
395config GENERIC_CALIBRATE_DELAY
396	def_bool y
397
398config ARCH_HAS_CPU_RELAX
399	def_bool y
400
401config ARCH_HIBERNATION_POSSIBLE
402	def_bool y
403
404config ARCH_SUSPEND_POSSIBLE
405	def_bool y
406
407config AUDIT_ARCH
408	def_bool y if X86_64
409
410config KASAN_SHADOW_OFFSET
411	hex
412	depends on KASAN
413	default 0xdffffc0000000000
414
415config HAVE_INTEL_TXT
416	def_bool y
417	depends on INTEL_IOMMU && ACPI
418
419config ARCH_SUPPORTS_UPROBES
420	def_bool y
421
422config FIX_EARLYCON_MEM
423	def_bool y
424
425config DYNAMIC_PHYSICAL_MASK
426	bool
427
428config PGTABLE_LEVELS
429	int
430	default 5 if X86_64
431	default 3 if X86_PAE
432	default 2
433
434menu "Processor type and features"
435
436config SMP
437	bool "Symmetric multi-processing support"
438	help
439	  This enables support for systems with more than one CPU. If you have
440	  a system with only one CPU, say N. If you have a system with more
441	  than one CPU, say Y.
442
443	  If you say N here, the kernel will run on uni- and multiprocessor
444	  machines, but will use only one CPU of a multiprocessor machine. If
445	  you say Y here, the kernel will run on many, but not all,
446	  uniprocessor machines. On a uniprocessor machine, the kernel
447	  will run faster if you say N here.
448
449	  People using multiprocessor machines who say Y here should also say
450	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
451	  Management" code will be disabled if you say Y here.
452
453	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
454	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
455	  <http://www.tldp.org/docs.html#howto>.
456
457	  If you don't know what to do here, say N.
458
459config X86_X2APIC
460	bool "x2APIC interrupt controller architecture support"
461	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
462	default y
463	help
464	  x2APIC is an interrupt controller architecture, a component of which
465	  (the local APIC) is present in the CPU. It allows faster access to
466	  the local APIC and supports a larger number of CPUs in the system
467	  than the predecessors.
468
469	  x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs
470	  in 2019, but it can be disabled by the BIOS. It is also frequently
471	  emulated in virtual machines, even when the host CPU does not support
472	  it. Support in the CPU can be checked by executing
473		grep x2apic /proc/cpuinfo
474
475	  If this configuration option is disabled, the kernel will boot with
476	  very reduced functionality and performance on some platforms that
477	  have x2APIC enabled. On the other hand, on hardware that does not
478	  support x2APIC, a kernel with this option enabled will just fallback
479	  to older APIC implementations.
480
481	  If in doubt, say Y.
482
483config AMD_SECURE_AVIC
484	bool "AMD Secure AVIC"
485	depends on AMD_MEM_ENCRYPT && X86_X2APIC
486	help
487	  Enable this to get AMD Secure AVIC support on guests that have this feature.
488
489	  AMD Secure AVIC provides hardware acceleration for performance sensitive
490	  APIC accesses and support for managing guest owned APIC state for SEV-SNP
491	  guests. Secure AVIC does not support xAPIC mode. It has functional
492	  dependency on x2apic being enabled in the guest.
493
494	  If you don't know what to do here, say N.
495
496config X86_POSTED_MSI
497	bool "Enable MSI and MSI-x delivery by posted interrupts"
498	depends on X86_64 && IRQ_REMAP
499	help
500	  This enables MSIs that are under interrupt remapping to be delivered as
501	  posted interrupts to the host kernel. Interrupt throughput can
502	  potentially be improved by coalescing CPU notifications during high
503	  frequency bursts.
504
505	  If you don't know what to do here, say N.
506
507config X86_MPPARSE
508	bool "Enable MPS table" if ACPI
509	default y
510	depends on X86_LOCAL_APIC
511	help
512	  For old smp systems that do not have proper acpi support. Newer systems
513	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
514
515config X86_CPU_RESCTRL
516	bool "x86 CPU resource control support"
517	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
518	depends on MISC_FILESYSTEMS
519	select ARCH_HAS_CPU_RESCTRL
520	select RESCTRL_FS
521	select RESCTRL_FS_PSEUDO_LOCK
522	help
523	  Enable x86 CPU resource control support.
524
525	  Provide support for the allocation and monitoring of system resources
526	  usage by the CPU.
527
528	  Intel calls this Intel Resource Director Technology
529	  (Intel(R) RDT). More information about RDT can be found in the
530	  Intel x86 Architecture Software Developer Manual.
531
532	  AMD calls this AMD Platform Quality of Service (AMD QoS).
533	  More information about AMD QoS can be found in the AMD64 Technology
534	  Platform Quality of Service Extensions manual.
535
536	  Say N if unsure.
537
538config X86_CPU_RESCTRL_INTEL_AET
539	bool "Intel Application Energy Telemetry"
540	depends on X86_64 && X86_CPU_RESCTRL && CPU_SUP_INTEL && INTEL_PMT_TELEMETRY=y && INTEL_TPMI=y
541	help
542	  Enable per-RMID telemetry events in resctrl.
543
544	  Intel feature that collects per-RMID execution data
545	  about energy consumption, measure of frequency independent
546	  activity and other performance metrics. Data is aggregated
547	  per package.
548
549	  Say N if unsure.
550
551config X86_FRED
552	bool "Flexible Return and Event Delivery"
553	depends on X86_64
554	help
555	  When enabled, use Flexible Return and Event Delivery
556	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
557	  ring transitions and exception/interrupt handling if the
558	  system supports it.
559
560config X86_EXTENDED_PLATFORM
561	bool "Support for extended (non-PC) x86 platforms"
562	default y
563	help
564	  If you disable this option then the kernel will only support
565	  standard PC platforms. (which covers the vast majority of
566	  systems out there.)
567
568	  If you enable this option then you'll be able to select support
569	  for the following non-PC x86 platforms, depending on the value of
570	  CONFIG_64BIT.
571
572	  32-bit platforms (CONFIG_64BIT=n):
573		Goldfish (mostly Android emulator)
574		Intel CE media processor (CE4100) SoC
575		Intel Quark
576		RDC R-321x SoC
577
578	  64-bit platforms (CONFIG_64BIT=y):
579		Numascale NumaChip
580		ScaleMP vSMP
581		SGI Ultraviolet
582		Merrifield/Moorefield MID devices
583		Goldfish (mostly Android emulator)
584
585	  If you have one of these systems, or if you want to build a
586	  generic distribution kernel, say Y here - otherwise say N.
587
588# This is an alphabetically sorted list of 64 bit extended platforms
589# Please maintain the alphabetic order if and when there are additions
590config X86_NUMACHIP
591	bool "Numascale NumaChip"
592	depends on X86_64
593	depends on X86_EXTENDED_PLATFORM
594	depends on NUMA
595	depends on SMP
596	depends on X86_X2APIC
597	depends on PCI_MMCONFIG
598	help
599	  Adds support for Numascale NumaChip large-SMP systems. Needed to
600	  enable more than ~168 cores.
601	  If you don't have one of these, you should say N here.
602
603config X86_VSMP
604	bool "ScaleMP vSMP"
605	select HYPERVISOR_GUEST
606	select PARAVIRT
607	depends on X86_64 && PCI
608	depends on X86_EXTENDED_PLATFORM
609	depends on SMP
610	help
611	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
612	  supposed to run on these EM64T-based machines.  Only choose this option
613	  if you have one of these machines.
614
615config X86_UV
616	bool "SGI Ultraviolet"
617	depends on X86_64
618	depends on X86_EXTENDED_PLATFORM
619	depends on NUMA
620	depends on EFI
621	depends on KEXEC_CORE
622	depends on X86_X2APIC
623	depends on PCI
624	help
625	  This option is needed in order to support SGI Ultraviolet systems.
626	  If you don't have one of these, you should say N here.
627
628config X86_INTEL_MID
629	bool "Intel Z34xx/Z35xx MID platform support"
630	depends on X86_EXTENDED_PLATFORM
631	depends on X86_PLATFORM_DEVICES
632	depends on PCI
633	depends on X86_64 || (EXPERT && PCI_GOANY)
634	depends on X86_IO_APIC
635	select I2C
636	select DW_APB_TIMER
637	select INTEL_SCU_PCI
638	help
639	  Select to build a kernel capable of supporting 64-bit Intel MID
640	  (Mobile Internet Device) platform systems which do not have
641	  the PCI legacy interfaces.
642
643	  The only supported devices are the 22nm Merrified (Z34xx)
644	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
645	  a small number of Android devices such as the Asus Zenfone 2,
646	  Asus FonePad 8 and Dell Venue 7.
647
648	  If you are building for a PC class system or non-MID tablet
649	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
650
651	  Intel MID platforms are based on an Intel processor and chipset which
652	  consume less power than most of the x86 derivatives.
653
654config X86_GOLDFISH
655	bool "Goldfish (Virtual Platform)"
656	depends on X86_EXTENDED_PLATFORM
657	help
658	  Enable support for the Goldfish virtual platform used primarily
659	  for Android development. Unless you are building for the Android
660	  Goldfish emulator say N here.
661
662# Following is an alphabetically sorted list of 32 bit extended platforms
663# Please maintain the alphabetic order if and when there are additions
664
665config X86_INTEL_CE
666	bool "CE4100 TV platform"
667	depends on PCI
668	depends on PCI_GODIRECT
669	depends on X86_IO_APIC
670	depends on X86_32
671	depends on X86_EXTENDED_PLATFORM
672	select X86_REBOOTFIXUPS
673	select OF
674	select OF_EARLY_FLATTREE
675	help
676	  Select for the Intel CE media processor (CE4100) SOC.
677	  This option compiles in support for the CE4100 SOC for settop
678	  boxes and media devices.
679
680config X86_INTEL_QUARK
681	bool "Intel Quark platform support"
682	depends on X86_32
683	depends on X86_EXTENDED_PLATFORM
684	depends on X86_PLATFORM_DEVICES
685	depends on PCI
686	depends on PCI_GOANY
687	depends on X86_IO_APIC
688	select IOSF_MBI
689	select INTEL_IMR
690	select COMMON_CLK
691	help
692	  Select to include support for Quark X1000 SoC.
693	  Say Y here if you have a Quark based system such as the Arduino
694	  compatible Intel Galileo.
695
696config X86_INTEL_LPSS
697	bool "Intel Low Power Subsystem Support"
698	depends on X86 && ACPI && PCI
699	select COMMON_CLK
700	select PINCTRL
701	select IOSF_MBI
702	help
703	  Select to build support for Intel Low Power Subsystem such as
704	  found on Intel Lynxpoint PCH. Selecting this option enables
705	  things like clock tree (common clock framework) and pincontrol
706	  which are needed by the LPSS peripheral drivers.
707
708config X86_AMD_PLATFORM_DEVICE
709	bool "AMD ACPI2Platform devices support"
710	depends on ACPI
711	select COMMON_CLK
712	select PINCTRL
713	help
714	  Select to interpret AMD specific ACPI device to platform device
715	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
716	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
717	  implemented under PINCTRL subsystem.
718
719config IOSF_MBI
720	tristate "Intel SoC IOSF Sideband support for SoC platforms"
721	depends on PCI
722	help
723	  This option enables sideband register access support for Intel SoC
724	  platforms. On these platforms the IOSF sideband is used in lieu of
725	  MSR's for some register accesses, mostly but not limited to thermal
726	  and power. Drivers may query the availability of this device to
727	  determine if they need the sideband in order to work on these
728	  platforms. The sideband is available on the following SoC products.
729	  This list is not meant to be exclusive.
730	   - BayTrail
731	   - Braswell
732	   - Quark
733
734	  You should say Y if you are running a kernel on one of these SoC's.
735
736config IOSF_MBI_DEBUG
737	bool "Enable IOSF sideband access through debugfs"
738	depends on IOSF_MBI && DEBUG_FS
739	help
740	  Select this option to expose the IOSF sideband access registers (MCR,
741	  MDR, MCRX) through debugfs to write and read register information from
742	  different units on the SoC. This is most useful for obtaining device
743	  state information for debug and analysis. As this is a general access
744	  mechanism, users of this option would have specific knowledge of the
745	  device they want to access.
746
747	  If you don't require the option or are in doubt, say N.
748
749config X86_SUPPORTS_MEMORY_FAILURE
750	def_bool y
751	# MCE code calls memory_failure():
752	depends on X86_MCE
753	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
754	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
755	depends on X86_64 || !SPARSEMEM
756	select ARCH_SUPPORTS_MEMORY_FAILURE
757
758config X86_32_IRIS
759	tristate "Eurobraille/Iris poweroff module"
760	depends on X86_32
761	help
762	  The Iris machines from EuroBraille do not have APM or ACPI support
763	  to shut themselves down properly.  A special I/O sequence is
764	  needed to do so, which is what this module does at
765	  kernel shutdown.
766
767	  This is only for Iris machines from EuroBraille.
768
769	  If unused, say N.
770
771config SCHED_OMIT_FRAME_POINTER
772	def_bool y
773	prompt "Single-depth WCHAN output"
774	depends on X86
775	help
776	  Calculate simpler /proc/<PID>/wchan values. If this option
777	  is disabled then wchan values will recurse back to the
778	  caller function. This provides more accurate wchan values,
779	  at the expense of slightly more scheduling overhead.
780
781	  If in doubt, say "Y".
782
783menuconfig HYPERVISOR_GUEST
784	bool "Linux guest support"
785	help
786	  Say Y here to enable options for running Linux under various hyper-
787	  visors. This option enables basic hypervisor detection and platform
788	  setup.
789
790	  If you say N, all options in this submenu will be skipped and
791	  disabled, and Linux guest support won't be built in.
792
793if HYPERVISOR_GUEST
794
795config PARAVIRT
796	bool "Enable paravirtualization code"
797	depends on HAVE_STATIC_CALL
798	select HAVE_PV_STEAL_CLOCK_GEN
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	select ARCH_HAS_LAZY_MMU_MODE
809
810config PARAVIRT_SPINLOCKS
811	bool "Paravirtualization layer for spinlocks"
812	depends on PARAVIRT && SMP
813	help
814	  Paravirtualized spinlocks allow a pvops backend to replace the
815	  spinlock implementation with something virtualization-friendly
816	  (for example, block the virtual CPU rather than spinning).
817
818	  It has a minimal impact on native kernels and gives a nice performance
819	  benefit on paravirtualized KVM / Xen kernels.
820
821	  If you are unsure how to answer this question, answer Y.
822
823config X86_HV_CALLBACK_VECTOR
824	def_bool n
825
826source "arch/x86/xen/Kconfig"
827
828config KVM_GUEST
829	bool "KVM Guest support (including kvmclock)"
830	depends on PARAVIRT
831	select PARAVIRT_CLOCK
832	select ARCH_CPUIDLE_HALTPOLL
833	select X86_HV_CALLBACK_VECTOR
834	default y
835	help
836	  This option enables various optimizations for running under the KVM
837	  hypervisor. It includes a paravirtualized clock, so that instead
838	  of relying on a PIT (or probably other) emulation by the
839	  underlying device model, the host provides the guest with
840	  timing infrastructure such as time of day, and system time
841
842config ARCH_CPUIDLE_HALTPOLL
843	def_bool n
844	prompt "Disable host haltpoll when loading haltpoll driver"
845	help
846	  If virtualized under KVM, disable host haltpoll.
847
848config PVH
849	bool "Support for running PVH guests"
850	help
851	  This option enables the PVH entry point for guest virtual machines
852	  as specified in the x86/HVM direct boot ABI.
853
854config PARAVIRT_TIME_ACCOUNTING
855	bool "Paravirtual steal time accounting"
856	depends on PARAVIRT
857	help
858	  Select this option to enable fine granularity task steal time
859	  accounting. Time spent executing other tasks in parallel with
860	  the current vCPU is discounted from the vCPU power. To account for
861	  that, there can be a small performance impact.
862
863	  If in doubt, say N here.
864
865config PARAVIRT_CLOCK
866	bool
867
868config JAILHOUSE_GUEST
869	bool "Jailhouse non-root cell support"
870	depends on X86_64 && PCI
871	select X86_PM_TIMER
872	help
873	  This option allows to run Linux as guest in a Jailhouse non-root
874	  cell. You can leave this option disabled if you only want to start
875	  Jailhouse and run Linux afterwards in the root cell.
876
877config ACRN_GUEST
878	bool "ACRN Guest support"
879	depends on X86_64
880	select X86_HV_CALLBACK_VECTOR
881	help
882	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
883	  a flexible, lightweight reference open-source hypervisor, built with
884	  real-time and safety-criticality in mind. It is built for embedded
885	  IOT with small footprint and real-time features. More details can be
886	  found in https://projectacrn.org/.
887
888config BHYVE_GUEST
889	bool "Bhyve (BSD Hypervisor) Guest support"
890	depends on X86_64
891	help
892	  This option allows to run Linux to recognise when it is running as a
893	  guest in the Bhyve hypervisor, and to support more than 255 vCPUs when
894	  when doing so. More details about Bhyve can be found at https://bhyve.org
895	  and https://wiki.freebsd.org/bhyve/.
896
897config INTEL_TDX_GUEST
898	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
899	depends on X86_64 && CPU_SUP_INTEL
900	depends on X86_X2APIC
901	depends on EFI_STUB
902	depends on PARAVIRT
903	select ARCH_HAS_CC_PLATFORM
904	select X86_MEM_ENCRYPT
905	select X86_MCE
906	select UNACCEPTED_MEMORY
907	help
908	  Support running as a guest under Intel TDX.  Without this support,
909	  the guest kernel can not boot or run under TDX.
910	  TDX includes memory encryption and integrity capabilities
911	  which protect the confidentiality and integrity of guest
912	  memory contents and CPU state. TDX guests are protected from
913	  some attacks from the VMM.
914
915endif # HYPERVISOR_GUEST
916
917source "arch/x86/Kconfig.cpu"
918
919config HPET_TIMER
920	def_bool X86_64
921	prompt "HPET Timer Support" if X86_32
922	help
923	  Use the IA-PC HPET (High Precision Event Timer) to manage
924	  time in preference to the PIT and RTC, if a HPET is
925	  present.
926	  HPET is the next generation timer replacing legacy 8254s.
927	  The HPET provides a stable time base on SMP
928	  systems, unlike the TSC, but it is more expensive to access,
929	  as it is off-chip.  The interface used is documented
930	  in the HPET spec, revision 1.
931
932	  You can safely choose Y here.  However, HPET will only be
933	  activated if the platform and the BIOS support this feature.
934	  Otherwise the 8254 will be used for timing services.
935
936	  Choose N to continue using the legacy 8254 timer.
937
938config HPET_EMULATE_RTC
939	def_bool y
940	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
941
942# Mark as expert because too many people got it wrong.
943# The code disables itself when not needed.
944config DMI
945	default y
946	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
947	bool "Enable DMI scanning" if EXPERT
948	help
949	  Enabled scanning of DMI to identify machine quirks. Say Y
950	  here unless you have verified that your setup is not
951	  affected by entries in the DMI blacklist. Required by PNP
952	  BIOS code.
953
954config GART_IOMMU
955	bool "Old AMD GART IOMMU support"
956	select IOMMU_HELPER
957	select SWIOTLB
958	depends on X86_64 && PCI && AMD_NB
959	help
960	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
961	  GART based hardware IOMMUs.
962
963	  The GART supports full DMA access for devices with 32-bit access
964	  limitations, on systems with more than 3 GB. This is usually needed
965	  for USB, sound, many IDE/SATA chipsets and some other devices.
966
967	  Newer systems typically have a modern AMD IOMMU, supported via
968	  the CONFIG_AMD_IOMMU=y config option.
969
970	  In normal configurations this driver is only active when needed:
971	  there's more than 3 GB of memory and the system contains a
972	  32-bit limited device.
973
974	  If unsure, say Y.
975
976config BOOT_VESA_SUPPORT
977	bool
978	help
979	  If true, at least one selected framebuffer driver can take advantage
980	  of VESA video modes set at an early boot stage via the vga= parameter.
981
982config MAXSMP
983	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
984	depends on X86_64 && SMP && DEBUG_KERNEL
985	select CPUMASK_OFFSTACK
986	help
987	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
988	  If unsure, say N.
989
990#
991# The maximum number of CPUs supported:
992#
993# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
994# and which can be configured interactively in the
995# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
996#
997# The ranges are different on 32-bit and 64-bit kernels, depending on
998# hardware capabilities and scalability features of the kernel.
999#
1000# ( If MAXSMP is enabled we just use the highest possible value and disable
1001#   interactive configuration. )
1002#
1003
1004config NR_CPUS_RANGE_BEGIN
1005	int
1006	default NR_CPUS_RANGE_END if MAXSMP
1007	default    1 if !SMP
1008	default    2
1009
1010config NR_CPUS_RANGE_END
1011	int
1012	depends on X86_32
1013	default    8 if  SMP
1014	default    1 if !SMP
1015
1016config NR_CPUS_RANGE_END
1017	int
1018	depends on X86_64
1019	default 8192 if  SMP && CPUMASK_OFFSTACK
1020	default  512 if  SMP && !CPUMASK_OFFSTACK
1021	default    1 if !SMP
1022
1023config NR_CPUS_DEFAULT
1024	int
1025	depends on X86_32
1026	default    8 if  SMP
1027	default    1 if !SMP
1028
1029config NR_CPUS_DEFAULT
1030	int
1031	depends on X86_64
1032	default 8192 if  MAXSMP
1033	default   64 if  SMP
1034	default    1 if !SMP
1035
1036config NR_CPUS
1037	int "Maximum number of CPUs" if SMP && !MAXSMP
1038	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1039	default NR_CPUS_DEFAULT
1040	help
1041	  This allows you to specify the maximum number of CPUs which this
1042	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1043	  supported value is 8192, otherwise the maximum value is 512.  The
1044	  minimum value which makes sense is 2.
1045
1046	  This is purely to save memory: each supported CPU adds about 8KB
1047	  to the kernel image.
1048
1049config SCHED_MC_PRIO
1050	bool "CPU core priorities scheduler support"
1051	depends on SCHED_MC
1052	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1053	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1054	select CPU_FREQ
1055	default y
1056	help
1057	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1058	  core ordering determined at manufacturing time, which allows
1059	  certain cores to reach higher turbo frequencies (when running
1060	  single threaded workloads) than others.
1061
1062	  Enabling this kernel feature teaches the scheduler about
1063	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1064	  scheduler's CPU selection logic accordingly, so that higher
1065	  overall system performance can be achieved.
1066
1067	  This feature will have no effect on CPUs without this feature.
1068
1069	  If unsure say Y here.
1070
1071config UP_LATE_INIT
1072	def_bool y
1073	depends on !SMP && X86_LOCAL_APIC
1074
1075config X86_UP_APIC
1076	bool "Local APIC support on uniprocessors" if !PCI_MSI
1077	default PCI_MSI
1078	depends on X86_32 && !SMP
1079	help
1080	  A local APIC (Advanced Programmable Interrupt Controller) is an
1081	  integrated interrupt controller in the CPU. If you have a single-CPU
1082	  system which has a processor with a local APIC, you can say Y here to
1083	  enable and use it. If you say Y here even though your machine doesn't
1084	  have a local APIC, then the kernel will still run with no slowdown at
1085	  all. The local APIC supports CPU-generated self-interrupts (timer,
1086	  performance counters), and the NMI watchdog which detects hard
1087	  lockups.
1088
1089config X86_UP_IOAPIC
1090	bool "IO-APIC support on uniprocessors"
1091	depends on X86_UP_APIC
1092	help
1093	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1094	  SMP-capable replacement for PC-style interrupt controllers. Most
1095	  SMP systems and many recent uniprocessor systems have one.
1096
1097	  If you have a single-CPU system with an IO-APIC, you can say Y here
1098	  to use it. If you say Y here even though your machine doesn't have
1099	  an IO-APIC, then the kernel will still run with no slowdown at all.
1100
1101config X86_LOCAL_APIC
1102	def_bool y
1103	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1104	select IRQ_DOMAIN_HIERARCHY
1105
1106config ACPI_MADT_WAKEUP
1107	def_bool y
1108	depends on X86_64
1109	depends on ACPI
1110	depends on SMP
1111	depends on X86_LOCAL_APIC
1112
1113config X86_IO_APIC
1114	def_bool y
1115	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1116
1117config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1118	bool "Reroute for broken boot IRQs"
1119	depends on X86_IO_APIC
1120	help
1121	  This option enables a workaround that fixes a source of
1122	  spurious interrupts. This is recommended when threaded
1123	  interrupt handling is used on systems where the generation of
1124	  superfluous "boot interrupts" cannot be disabled.
1125
1126	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1127	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1128	  kernel does during interrupt handling). On chipsets where this
1129	  boot IRQ generation cannot be disabled, this workaround keeps
1130	  the original IRQ line masked so that only the equivalent "boot
1131	  IRQ" is delivered to the CPUs. The workaround also tells the
1132	  kernel to set up the IRQ handler on the boot IRQ line. In this
1133	  way only one interrupt is delivered to the kernel. Otherwise
1134	  the spurious second interrupt may cause the kernel to bring
1135	  down (vital) interrupt lines.
1136
1137	  Only affects "broken" chipsets. Interrupt sharing may be
1138	  increased on these systems.
1139
1140config X86_MCE
1141	bool "Machine Check / overheating reporting"
1142	select GENERIC_ALLOCATOR
1143	default y
1144	help
1145	  Machine Check support allows the processor to notify the
1146	  kernel if it detects a problem (e.g. overheating, data corruption).
1147	  The action the kernel takes depends on the severity of the problem,
1148	  ranging from warning messages to halting the machine.
1149
1150config X86_MCELOG_LEGACY
1151	bool "Support for deprecated /dev/mcelog character device"
1152	depends on X86_MCE
1153	help
1154	  Enable support for /dev/mcelog which is needed by the old mcelog
1155	  userspace logging daemon. Consider switching to the new generation
1156	  rasdaemon solution.
1157
1158config X86_MCE_INTEL
1159	def_bool y
1160	prompt "Intel MCE features"
1161	depends on X86_MCE && X86_LOCAL_APIC
1162	help
1163	  Additional support for intel specific MCE features such as
1164	  the thermal monitor.
1165
1166config X86_MCE_AMD
1167	def_bool y
1168	prompt "AMD MCE features"
1169	depends on X86_MCE && X86_LOCAL_APIC
1170	help
1171	  Additional support for AMD specific MCE features such as
1172	  the DRAM Error Threshold.
1173
1174config X86_ANCIENT_MCE
1175	bool "Support for old Pentium 5 / WinChip machine checks"
1176	depends on X86_32 && X86_MCE
1177	help
1178	  Include support for machine check handling on old Pentium 5 or WinChip
1179	  systems. These typically need to be enabled explicitly on the command
1180	  line.
1181
1182config X86_MCE_THRESHOLD
1183	depends on X86_MCE_AMD || X86_MCE_INTEL
1184	def_bool y
1185
1186config X86_MCE_INJECT
1187	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1188	tristate "Machine check injector support"
1189	help
1190	  Provide support for injecting machine checks for testing purposes.
1191	  If you don't know what a machine check is and you don't do kernel
1192	  QA it is safe to say n.
1193
1194source "arch/x86/events/Kconfig"
1195
1196config X86_LEGACY_VM86
1197	bool "Legacy VM86 support"
1198	depends on X86_32
1199	help
1200	  This option allows user programs to put the CPU into V8086
1201	  mode, which is an 80286-era approximation of 16-bit real mode.
1202
1203	  Some very old versions of X and/or vbetool require this option
1204	  for user mode setting.  Similarly, DOSEMU will use it if
1205	  available to accelerate real mode DOS programs.  However, any
1206	  recent version of DOSEMU, X, or vbetool should be fully
1207	  functional even without kernel VM86 support, as they will all
1208	  fall back to software emulation. Nevertheless, if you are using
1209	  a 16-bit DOS program where 16-bit performance matters, vm86
1210	  mode might be faster than emulation and you might want to
1211	  enable this option.
1212
1213	  Note that any app that works on a 64-bit kernel is unlikely to
1214	  need this option, as 64-bit kernels don't, and can't, support
1215	  V8086 mode. This option is also unrelated to 16-bit protected
1216	  mode and is not needed to run most 16-bit programs under Wine.
1217
1218	  Enabling this option increases the complexity of the kernel
1219	  and slows down exception handling a tiny bit.
1220
1221	  If unsure, say N here.
1222
1223config VM86
1224	bool
1225	default X86_LEGACY_VM86
1226
1227config X86_16BIT
1228	bool "Enable support for 16-bit segments" if EXPERT
1229	default y
1230	depends on MODIFY_LDT_SYSCALL
1231	help
1232	  This option is required by programs like Wine to run 16-bit
1233	  protected mode legacy code on x86 processors.  Disabling
1234	  this option saves about 300 bytes on i386, or around 6K text
1235	  plus 16K runtime memory on x86-64,
1236
1237config X86_ESPFIX32
1238	def_bool y
1239	depends on X86_16BIT && X86_32
1240
1241config X86_ESPFIX64
1242	def_bool y
1243	depends on X86_16BIT && X86_64
1244
1245config X86_VSYSCALL_EMULATION
1246	bool "Enable vsyscall emulation" if EXPERT
1247	default y
1248	depends on X86_64
1249	help
1250	  This enables emulation of the legacy vsyscall page.  Disabling
1251	  it is roughly equivalent to booting with vsyscall=none, except
1252	  that it will also disable the helpful warning if a program
1253	  tries to use a vsyscall.  With this option set to N, offending
1254	  programs will just segfault, citing addresses of the form
1255	  0xffffffffff600?00.
1256
1257	  This option is required by many programs built before 2013, and
1258	  care should be used even with newer programs if set to N.
1259
1260	  Disabling this option saves about 7K of kernel size and
1261	  possibly 4K of additional runtime pagetable memory.
1262
1263config X86_IOPL_IOPERM
1264	bool "IOPERM and IOPL Emulation"
1265	default y
1266	help
1267	  This enables the ioperm() and iopl() syscalls which are necessary
1268	  for legacy applications.
1269
1270	  Legacy IOPL support is an overbroad mechanism which allows user
1271	  space aside of accessing all 65536 I/O ports also to disable
1272	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1273	  capabilities and permission from potentially active security
1274	  modules.
1275
1276	  The emulation restricts the functionality of the syscall to
1277	  only allowing the full range I/O port access, but prevents the
1278	  ability to disable interrupts from user space which would be
1279	  granted if the hardware IOPL mechanism would be used.
1280
1281config TOSHIBA
1282	tristate "Toshiba Laptop support"
1283	depends on X86_32
1284	help
1285	  This adds a driver to safely access the System Management Mode of
1286	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1287	  not work on models with a Phoenix BIOS. The System Management Mode
1288	  is used to set the BIOS and power saving options on Toshiba portables.
1289
1290	  For information on utilities to make use of this driver see the
1291	  Toshiba Linux utilities web site at:
1292	  <http://www.buzzard.org.uk/toshiba/>.
1293
1294	  Say Y if you intend to run this kernel on a Toshiba portable.
1295	  Say N otherwise.
1296
1297config X86_REBOOTFIXUPS
1298	bool "Enable X86 board specific fixups for reboot"
1299	depends on X86_32
1300	help
1301	  This enables chipset and/or board specific fixups to be done
1302	  in order to get reboot to work correctly. This is only needed on
1303	  some combinations of hardware and BIOS. The symptom, for which
1304	  this config is intended, is when reboot ends with a stalled/hung
1305	  system.
1306
1307	  Currently, the only fixup is for the Geode machines using
1308	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1309
1310	  Say Y if you want to enable the fixup. Currently, it's safe to
1311	  enable this option even if you don't need it.
1312	  Say N otherwise.
1313
1314config MICROCODE
1315	def_bool y
1316	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1317	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1318
1319config MICROCODE_INITRD32
1320	def_bool y
1321	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1322
1323config MICROCODE_LATE_LOADING
1324	bool "Late microcode loading (DANGEROUS)"
1325	default n
1326	depends on MICROCODE && SMP
1327	help
1328	  Loading microcode late, when the system is up and executing instructions
1329	  is a tricky business and should be avoided if possible. Just the sequence
1330	  of synchronizing all cores and SMT threads is one fragile dance which does
1331	  not guarantee that cores might not softlock after the loading. Therefore,
1332	  use this at your own risk. Late loading taints the kernel unless the
1333	  microcode header indicates that it is safe for late loading via the
1334	  minimal revision check. This minimal revision check can be enforced on
1335	  the kernel command line with "microcode=force_minrev".
1336
1337config MICROCODE_LATE_FORCE_MINREV
1338	bool "Enforce late microcode loading minimal revision check"
1339	default n
1340	depends on MICROCODE_LATE_LOADING
1341	help
1342	  To prevent that users load microcode late which modifies already
1343	  in use features, newer microcode patches have a minimum revision field
1344	  in the microcode header, which tells the kernel which minimum
1345	  revision must be active in the CPU to safely load that new microcode
1346	  late into the running system. If disabled the check will not
1347	  be enforced but the kernel will be tainted when the minimal
1348	  revision check fails.
1349
1350	  This minimal revision check can also be controlled via the
1351	  "microcode=force_minrev" parameter on the kernel command line.
1352
1353	  If unsure say Y.
1354
1355config MICROCODE_DBG
1356	bool "Enable microcode loader debugging"
1357	default n
1358	depends on MICROCODE
1359	help
1360	  Enable code which allows to debug the microcode loader. When running
1361	  in a guest the patch loading is simulated but everything else
1362	  related to patch parsing and handling is done as on baremetal with
1363	  the purpose of debugging solely the software side of things. On
1364	  baremetal, it simply dumps additional debugging information during
1365	  normal operation.
1366
1367	  You almost certainly want to say n here.
1368
1369config X86_MSR
1370	tristate "/dev/cpu/*/msr - Model-specific register support"
1371	help
1372	  This device gives privileged processes access to the x86
1373	  Model-Specific Registers (MSRs).  It is a character device with
1374	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1375	  MSR accesses are directed to a specific CPU on multi-processor
1376	  systems.
1377
1378config X86_CPUID
1379	tristate "/dev/cpu/*/cpuid - CPU information support"
1380	help
1381	  This device gives processes access to the x86 CPUID instruction to
1382	  be executed on a specific processor.  It is a character device
1383	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1384	  /dev/cpu/31/cpuid.
1385
1386config HIGHMEM4G
1387	bool "High Memory Support"
1388	depends on X86_32
1389	help
1390	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1391	  However, the address space of 32-bit x86 processors is only 4
1392	  Gigabytes large. That means that, if you have a large amount of
1393	  physical memory, not all of it can be "permanently mapped" by the
1394	  kernel. The physical memory that's not permanently mapped is called
1395	  "high memory".
1396
1397	  If you are compiling a kernel which will never run on a machine with
1398	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1399	  choice and suitable for most users). This will result in a "3GB/1GB"
1400	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1401	  space and the remaining part of the 4GB virtual memory space is used
1402	  by the kernel to permanently map as much physical memory as
1403	  possible.
1404
1405	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1406	  answer "Y" here.
1407
1408	  If unsure, say N.
1409
1410choice
1411	prompt "Memory split" if EXPERT
1412	default VMSPLIT_3G
1413	depends on X86_32
1414	help
1415	  Select the desired split between kernel and user memory.
1416
1417	  If the address range available to the kernel is less than the
1418	  physical memory installed, the remaining memory will be available
1419	  as "high memory". Accessing high memory is a little more costly
1420	  than low memory, as it needs to be mapped into the kernel first.
1421	  Note that increasing the kernel address space limits the range
1422	  available to user programs, making the address space there
1423	  tighter.  Selecting anything other than the default 3G/1G split
1424	  will also likely make your kernel incompatible with binary-only
1425	  kernel modules.
1426
1427	  If you are not absolutely sure what you are doing, leave this
1428	  option alone!
1429
1430	config VMSPLIT_3G
1431		bool "3G/1G user/kernel split"
1432	config VMSPLIT_3G_OPT
1433		depends on !X86_PAE
1434		bool "3G/1G user/kernel split (for full 1G low memory)"
1435	config VMSPLIT_2G
1436		bool "2G/2G user/kernel split"
1437	config VMSPLIT_2G_OPT
1438		depends on !X86_PAE
1439		bool "2G/2G user/kernel split (for full 2G low memory)"
1440	config VMSPLIT_1G
1441		bool "1G/3G user/kernel split"
1442endchoice
1443
1444config PAGE_OFFSET
1445	hex
1446	default 0xB0000000 if VMSPLIT_3G_OPT
1447	default 0x80000000 if VMSPLIT_2G
1448	default 0x78000000 if VMSPLIT_2G_OPT
1449	default 0x40000000 if VMSPLIT_1G
1450	default 0xC0000000
1451	depends on X86_32
1452
1453config HIGHMEM
1454	def_bool HIGHMEM4G
1455
1456config X86_PAE
1457	bool "PAE (Physical Address Extension) Support"
1458	depends on X86_32 && X86_HAVE_PAE
1459	select PHYS_ADDR_T_64BIT
1460	help
1461	  PAE is required for NX support, and furthermore enables
1462	  larger swapspace support for non-overcommit purposes. It
1463	  has the cost of more pagetable lookup overhead, and also
1464	  consumes more pagetable space per process.
1465
1466config X86_DIRECT_GBPAGES
1467	def_bool y
1468	depends on X86_64
1469	help
1470	  Certain kernel features effectively disable kernel
1471	  linear 1 GB mappings (even if the CPU otherwise
1472	  supports them), so don't confuse the user by printing
1473	  that we have them enabled.
1474
1475config X86_CPA_STATISTICS
1476	bool "Enable statistic for Change Page Attribute"
1477	depends on DEBUG_FS
1478	help
1479	  Expose statistics about the Change Page Attribute mechanism, which
1480	  helps to determine the effectiveness of preserving large and huge
1481	  page mappings when mapping protections are changed.
1482
1483config X86_MEM_ENCRYPT
1484	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1485	select DYNAMIC_PHYSICAL_MASK
1486	def_bool n
1487
1488config AMD_MEM_ENCRYPT
1489	bool "AMD Secure Memory Encryption (SME) support"
1490	depends on X86_64 && CPU_SUP_AMD
1491	depends on EFI_STUB
1492	select DMA_COHERENT_POOL
1493	select ARCH_USE_MEMREMAP_PROT
1494	select INSTRUCTION_DECODER
1495	select ARCH_HAS_CC_PLATFORM
1496	select X86_MEM_ENCRYPT
1497	select UNACCEPTED_MEMORY
1498	select CRYPTO_LIB_AESGCM
1499	help
1500	  Say yes to enable support for the encryption of system memory.
1501	  This requires an AMD processor that supports Secure Memory
1502	  Encryption (SME).
1503
1504# Common NUMA Features
1505config NUMA
1506	bool "NUMA Memory Allocation and Scheduler Support"
1507	depends on SMP
1508	depends on X86_64
1509	select USE_PERCPU_NUMA_NODE_ID
1510	select OF_NUMA if OF
1511	help
1512	  Enable NUMA (Non-Uniform Memory Access) support.
1513
1514	  The kernel will try to allocate memory used by a CPU on the
1515	  local memory controller of the CPU and add some more
1516	  NUMA awareness to the kernel.
1517
1518	  For 64-bit this is recommended if the system is Intel Core i7
1519	  (or later), AMD Opteron, or EM64T NUMA.
1520
1521	  Otherwise, you should say N.
1522
1523config AMD_NUMA
1524	def_bool y
1525	prompt "Old style AMD Opteron NUMA detection"
1526	depends on X86_64 && NUMA && PCI
1527	help
1528	  Enable AMD NUMA node topology detection.  You should say Y here if
1529	  you have a multi processor AMD system. This uses an old method to
1530	  read the NUMA configuration directly from the builtin Northbridge
1531	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1532	  which also takes priority if both are compiled in.
1533
1534config X86_64_ACPI_NUMA
1535	def_bool y
1536	prompt "ACPI NUMA detection"
1537	depends on X86_64 && NUMA && ACPI && PCI
1538	select ACPI_NUMA
1539	help
1540	  Enable ACPI SRAT based node topology detection.
1541
1542config NODES_SHIFT
1543	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1544	range 1 10
1545	default "10" if MAXSMP
1546	default "6" if X86_64
1547	default "3"
1548	depends on NUMA
1549	help
1550	  Specify the maximum number of NUMA Nodes available on the target
1551	  system.  Increases memory reserved to accommodate various tables.
1552
1553config ARCH_FLATMEM_ENABLE
1554	def_bool y
1555	depends on X86_32 && !NUMA
1556
1557config ARCH_SPARSEMEM_ENABLE
1558	def_bool y
1559	select SPARSEMEM_STATIC if X86_32
1560	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1561
1562config ARCH_SPARSEMEM_DEFAULT
1563	def_bool X86_64 || (NUMA && X86_32)
1564
1565config ARCH_SELECT_MEMORY_MODEL
1566	def_bool y
1567	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1568
1569config ARCH_MEMORY_PROBE
1570	bool "Enable sysfs memory/probe interface"
1571	depends on MEMORY_HOTPLUG
1572	help
1573	  This option enables a sysfs memory/probe interface for testing.
1574	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1575	  If you are unsure how to answer this question, answer N.
1576
1577config ARCH_PROC_KCORE_TEXT
1578	def_bool y
1579	depends on X86_64 && PROC_KCORE
1580
1581config ILLEGAL_POINTER_VALUE
1582	hex
1583	default 0 if X86_32
1584	default 0xdead000000000000 if X86_64
1585
1586config X86_PMEM_LEGACY_DEVICE
1587	bool
1588
1589config X86_PMEM_LEGACY
1590	tristate "Support non-standard NVDIMMs and ADR protected memory"
1591	depends on PHYS_ADDR_T_64BIT
1592	depends on BLK_DEV
1593	select X86_PMEM_LEGACY_DEVICE
1594	select NUMA_KEEP_MEMINFO if NUMA
1595	select LIBNVDIMM
1596	help
1597	  Treat memory marked using the non-standard e820 type of 12 as used
1598	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1599	  The kernel will offer these regions to the 'pmem' driver so
1600	  they can be used for persistent storage.
1601
1602	  Say Y if unsure.
1603
1604config X86_CHECK_BIOS_CORRUPTION
1605	bool "Check for low memory corruption"
1606	help
1607	  Periodically check for memory corruption in low memory, which
1608	  is suspected to be caused by BIOS.  Even when enabled in the
1609	  configuration, it is disabled at runtime.  Enable it by
1610	  setting "memory_corruption_check=1" on the kernel command
1611	  line.  By default it scans the low 64k of memory every 60
1612	  seconds; see the memory_corruption_check_size and
1613	  memory_corruption_check_period parameters in
1614	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1615
1616	  When enabled with the default parameters, this option has
1617	  almost no overhead, as it reserves a relatively small amount
1618	  of memory and scans it infrequently.  It both detects corruption
1619	  and prevents it from affecting the running system.
1620
1621	  It is, however, intended as a diagnostic tool; if repeatable
1622	  BIOS-originated corruption always affects the same memory,
1623	  you can use memmap= to prevent the kernel from using that
1624	  memory.
1625
1626config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1627	bool "Set the default setting of memory_corruption_check"
1628	depends on X86_CHECK_BIOS_CORRUPTION
1629	default y
1630	help
1631	  Set whether the default state of memory_corruption_check is
1632	  on or off.
1633
1634config MTRR
1635	def_bool y
1636	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1637	help
1638	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1639	  the Memory Type Range Registers (MTRRs) may be used to control
1640	  processor access to memory ranges. This is most useful if you have
1641	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1642	  allows bus write transfers to be combined into a larger transfer
1643	  before bursting over the PCI/AGP bus. This can increase performance
1644	  of image write operations 2.5 times or more. Saying Y here creates a
1645	  /proc/mtrr file which may be used to manipulate your processor's
1646	  MTRRs. Typically the X server should use this.
1647
1648	  This code has a reasonably generic interface so that similar
1649	  control registers on other processors can be easily supported
1650	  as well:
1651
1652	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1653	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1654	  these, the ARRs are used to emulate the MTRRs.
1655	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1656	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1657	  write-combining. All of these processors are supported by this code
1658	  and it makes sense to say Y here if you have one of them.
1659
1660	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1661	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1662	  can lead to all sorts of problems, so it's good to say Y here.
1663
1664	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1665	  just add about 9 KB to your kernel.
1666
1667	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1668
1669config MTRR_SANITIZER
1670	def_bool y
1671	prompt "MTRR cleanup support"
1672	depends on MTRR
1673	help
1674	  Convert MTRR layout from continuous to discrete, so X drivers can
1675	  add writeback entries.
1676
1677	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1678	  The largest mtrr entry size for a continuous block can be set with
1679	  mtrr_chunk_size.
1680
1681	  If unsure, say Y.
1682
1683config MTRR_SANITIZER_ENABLE_DEFAULT
1684	int "MTRR cleanup enable value (0-1)"
1685	range 0 1
1686	default "0"
1687	depends on MTRR_SANITIZER
1688	help
1689	  Enable mtrr cleanup default value
1690
1691config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1692	int "MTRR cleanup spare reg num (0-7)"
1693	range 0 7
1694	default "1"
1695	depends on MTRR_SANITIZER
1696	help
1697	  mtrr cleanup spare entries default, it can be changed via
1698	  mtrr_spare_reg_nr=N on the kernel command line.
1699
1700config X86_PAT
1701	def_bool y
1702	prompt "x86 PAT support" if EXPERT
1703	depends on MTRR
1704	select ARCH_USES_PG_ARCH_2
1705	help
1706	  Use PAT attributes to setup page level cache control.
1707
1708	  PATs are the modern equivalents of MTRRs and are much more
1709	  flexible than MTRRs.
1710
1711	  Say N here if you see bootup problems (boot crash, boot hang,
1712	  spontaneous reboots) or a non-working video driver.
1713
1714	  If unsure, say Y.
1715
1716config X86_UMIP
1717	def_bool y
1718	prompt "User Mode Instruction Prevention" if EXPERT
1719	help
1720	  User Mode Instruction Prevention (UMIP) is a security feature in
1721	  some x86 processors. If enabled, a general protection fault is
1722	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1723	  executed in user mode. These instructions unnecessarily expose
1724	  information about the hardware state.
1725
1726	  The vast majority of applications do not use these instructions.
1727	  For the very few that do, software emulation is provided in
1728	  specific cases in protected and virtual-8086 modes. Emulated
1729	  results are dummy.
1730
1731config CC_HAS_IBT
1732	# GCC >= 9 and binutils >= 2.29
1733	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1734	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || CC_IS_CLANG) && \
1735		  $(as-instr,endbr64)
1736
1737config X86_CET
1738	def_bool n
1739	help
1740	  CET features configured (Shadow stack or IBT)
1741
1742config X86_KERNEL_IBT
1743	prompt "Indirect Branch Tracking"
1744	def_bool y
1745	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1746	select OBJTOOL
1747	select X86_CET
1748	help
1749	  Build the kernel with support for Indirect Branch Tracking, a
1750	  hardware support course-grain forward-edge Control Flow Integrity
1751	  protection. It enforces that all indirect calls must land on
1752	  an ENDBR instruction, as such, the compiler will instrument the
1753	  code with them to make this happen.
1754
1755	  In addition to building the kernel with IBT, seal all functions that
1756	  are not indirect call targets, avoiding them ever becoming one.
1757
1758	  This requires LTO like objtool runs and will slow down the build. It
1759	  does significantly reduce the number of ENDBR instructions in the
1760	  kernel image.
1761
1762config X86_INTEL_MEMORY_PROTECTION_KEYS
1763	prompt "Memory Protection Keys"
1764	def_bool y
1765	# Note: only available in 64-bit mode
1766	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1767	select ARCH_USES_HIGH_VMA_FLAGS
1768	select ARCH_HAS_PKEYS
1769	help
1770	  Memory Protection Keys provides a mechanism for enforcing
1771	  page-based protections, but without requiring modification of the
1772	  page tables when an application changes protection domains.
1773
1774	  For details, see Documentation/core-api/protection-keys.rst
1775
1776	  If unsure, say y.
1777
1778config ARCH_PKEY_BITS
1779	int
1780	default 4
1781
1782choice
1783	prompt "TSX enable mode"
1784	depends on CPU_SUP_INTEL
1785	default X86_INTEL_TSX_MODE_AUTO
1786	help
1787	  Intel's TSX (Transactional Synchronization Extensions) feature
1788	  allows to optimize locking protocols through lock elision which
1789	  can lead to a noticeable performance boost.
1790
1791	  On the other hand it has been shown that TSX can be exploited
1792	  to form side channel attacks (e.g. TAA) and chances are there
1793	  will be more of those attacks discovered in the future.
1794
1795	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1796	  might override this decision by tsx=on the command line parameter.
1797	  Even with TSX enabled, the kernel will attempt to enable the best
1798	  possible TAA mitigation setting depending on the microcode available
1799	  for the particular machine.
1800
1801	  This option allows to set the default tsx mode between tsx=on, =off
1802	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1803	  details.
1804
1805	  Say off if not sure, auto if TSX is in use but it should be used on safe
1806	  platforms or on if TSX is in use and the security aspect of tsx is not
1807	  relevant.
1808
1809config X86_INTEL_TSX_MODE_OFF
1810	bool "off"
1811	help
1812	  TSX is disabled if possible - equals to tsx=off command line parameter.
1813
1814config X86_INTEL_TSX_MODE_ON
1815	bool "on"
1816	help
1817	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1818	  line parameter.
1819
1820config X86_INTEL_TSX_MODE_AUTO
1821	bool "auto"
1822	help
1823	  TSX is enabled on TSX capable HW that is believed to be safe against
1824	  side channel attacks- equals the tsx=auto command line parameter.
1825endchoice
1826
1827config X86_SGX
1828	bool "Software Guard eXtensions (SGX)"
1829	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1830	select CRYPTO_LIB_SHA256
1831	select MMU_NOTIFIER
1832	select NUMA_KEEP_MEMINFO if NUMA
1833	select XARRAY_MULTI
1834	help
1835	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1836	  that can be used by applications to set aside private regions of code
1837	  and data, referred to as enclaves. An enclave's private memory can
1838	  only be accessed by code running within the enclave. Accesses from
1839	  outside the enclave, including other enclaves, are disallowed by
1840	  hardware.
1841
1842	  If unsure, say N.
1843
1844config X86_USER_SHADOW_STACK
1845	bool "X86 userspace shadow stack"
1846	depends on AS_WRUSS
1847	depends on X86_64
1848	depends on PER_VMA_LOCK
1849	select ARCH_USES_HIGH_VMA_FLAGS
1850	select ARCH_HAS_USER_SHADOW_STACK
1851	select X86_CET
1852	help
1853	  Shadow stack protection is a hardware feature that detects function
1854	  return address corruption.  This helps mitigate ROP attacks.
1855	  Applications must be enabled to use it, and old userspace does not
1856	  get protection "for free".
1857
1858	  CPUs supporting shadow stacks were first released in 2020.
1859
1860	  See Documentation/arch/x86/shstk.rst for more information.
1861
1862	  If unsure, say N.
1863
1864config INTEL_TDX_HOST
1865	bool "Intel Trust Domain Extensions (TDX) host support"
1866	depends on CPU_SUP_INTEL
1867	depends on X86_64
1868	depends on KVM_INTEL
1869	depends on X86_X2APIC
1870	select ARCH_KEEP_MEMBLOCK
1871	depends on CONTIG_ALLOC
1872	depends on X86_MCE
1873	help
1874	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1875	  host and certain physical attacks.  This option enables necessary TDX
1876	  support in the host kernel to run confidential VMs.
1877
1878	  If unsure, say N.
1879
1880config EFI
1881	bool "EFI runtime service support"
1882	depends on ACPI
1883	select UCS2_STRING
1884	select EFI_RUNTIME_WRAPPERS
1885	select ARCH_USE_MEMREMAP_PROT
1886	select EFI_RUNTIME_MAP if KEXEC_CORE
1887	help
1888	  This enables the kernel to use EFI runtime services that are
1889	  available (such as the EFI variable services).
1890
1891	  This option is only useful on systems that have EFI firmware.
1892	  In addition, you should use the latest ELILO loader available
1893	  at <http://elilo.sourceforge.net> in order to take advantage
1894	  of EFI runtime services. However, even with this option, the
1895	  resultant kernel should continue to boot on existing non-EFI
1896	  platforms.
1897
1898config EFI_STUB
1899	bool "EFI stub support"
1900	depends on EFI
1901	select RELOCATABLE
1902	help
1903	  This kernel feature allows a bzImage to be loaded directly
1904	  by EFI firmware without the use of a bootloader.
1905
1906	  See Documentation/admin-guide/efi-stub.rst for more information.
1907
1908config EFI_HANDOVER_PROTOCOL
1909	bool "EFI handover protocol (DEPRECATED)"
1910	depends on EFI_STUB
1911	default y
1912	help
1913	  Select this in order to include support for the deprecated EFI
1914	  handover protocol, which defines alternative entry points into the
1915	  EFI stub.  This is a practice that has no basis in the UEFI
1916	  specification, and requires a priori knowledge on the part of the
1917	  bootloader about Linux/x86 specific ways of passing the command line
1918	  and initrd, and where in memory those assets may be loaded.
1919
1920	  If in doubt, say Y. Even though the corresponding support is not
1921	  present in upstream GRUB or other bootloaders, most distros build
1922	  GRUB with numerous downstream patches applied, and may rely on the
1923	  handover protocol as as result.
1924
1925config EFI_MIXED
1926	bool "EFI mixed-mode support"
1927	depends on EFI_STUB && X86_64
1928	help
1929	  Enabling this feature allows a 64-bit kernel to be booted
1930	  on a 32-bit firmware, provided that your CPU supports 64-bit
1931	  mode.
1932
1933	  Note that it is not possible to boot a mixed-mode enabled
1934	  kernel via the EFI boot stub - a bootloader that supports
1935	  the EFI handover protocol must be used.
1936
1937	  If unsure, say N.
1938
1939config EFI_RUNTIME_MAP
1940	bool "Export EFI runtime maps to sysfs" if EXPERT
1941	depends on EFI
1942	help
1943	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1944	  That memory map is required by the 2nd kernel to set up EFI virtual
1945	  mappings after kexec, but can also be used for debugging purposes.
1946
1947	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1948
1949source "kernel/Kconfig.hz"
1950
1951config ARCH_SUPPORTS_KEXEC
1952	def_bool y
1953
1954config ARCH_SUPPORTS_KEXEC_FILE
1955	def_bool X86_64
1956
1957config ARCH_SELECTS_KEXEC_FILE
1958	def_bool y
1959	depends on KEXEC_FILE
1960	select HAVE_IMA_KEXEC if IMA
1961
1962config ARCH_SUPPORTS_KEXEC_PURGATORY
1963	def_bool y
1964
1965config ARCH_SUPPORTS_KEXEC_SIG
1966	def_bool y
1967
1968config ARCH_SUPPORTS_KEXEC_SIG_FORCE
1969	def_bool y
1970
1971config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
1972	def_bool y
1973
1974config ARCH_SUPPORTS_KEXEC_JUMP
1975	def_bool y
1976
1977config ARCH_SUPPORTS_KEXEC_HANDOVER
1978	def_bool X86_64
1979
1980config ARCH_SUPPORTS_CRASH_DUMP
1981	def_bool X86_64 || (X86_32 && HIGHMEM)
1982
1983config ARCH_DEFAULT_CRASH_DUMP
1984	def_bool y
1985
1986config ARCH_SUPPORTS_CRASH_HOTPLUG
1987	def_bool y
1988
1989config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
1990	def_bool CRASH_RESERVE
1991
1992config PHYSICAL_START
1993	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
1994	default "0x1000000"
1995	help
1996	  This gives the physical address where the kernel is loaded.
1997
1998	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
1999	  will decompress itself to above physical address and run from there.
2000	  Otherwise, bzImage will run from the address where it has been loaded
2001	  by the boot loader. The only exception is if it is loaded below the
2002	  above physical address, in which case it will relocate itself there.
2003
2004	  In normal kdump cases one does not have to set/change this option
2005	  as now bzImage can be compiled as a completely relocatable image
2006	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2007	  address. This option is mainly useful for the folks who don't want
2008	  to use a bzImage for capturing the crash dump and want to use a
2009	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2010	  to be specifically compiled to run from a specific memory area
2011	  (normally a reserved region) and this option comes handy.
2012
2013	  So if you are using bzImage for capturing the crash dump,
2014	  leave the value here unchanged to 0x1000000 and set
2015	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2016	  for capturing the crash dump change this value to start of
2017	  the reserved region.  In other words, it can be set based on
2018	  the "X" value as specified in the "crashkernel=YM@XM"
2019	  command line boot parameter passed to the panic-ed
2020	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2021	  for more details about crash dumps.
2022
2023	  Usage of bzImage for capturing the crash dump is recommended as
2024	  one does not have to build two kernels. Same kernel can be used
2025	  as production kernel and capture kernel. Above option should have
2026	  gone away after relocatable bzImage support is introduced. But it
2027	  is present because there are users out there who continue to use
2028	  vmlinux for dump capture. This option should go away down the
2029	  line.
2030
2031	  Don't change this unless you know what you are doing.
2032
2033config RELOCATABLE
2034	bool "Build a relocatable kernel"
2035	default y
2036	help
2037	  This builds a kernel image that retains relocation information
2038	  so it can be loaded someplace besides the default 1MB.
2039	  The relocations tend to make the kernel binary about 10% larger,
2040	  but are discarded at runtime.
2041
2042	  One use is for the kexec on panic case where the recovery kernel
2043	  must live at a different physical address than the primary
2044	  kernel.
2045
2046	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2047	  it has been loaded at and the compile time physical address
2048	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2049
2050config RANDOMIZE_BASE
2051	bool "Randomize the address of the kernel image (KASLR)"
2052	depends on RELOCATABLE
2053	default y
2054	help
2055	  In support of Kernel Address Space Layout Randomization (KASLR),
2056	  this randomizes the physical address at which the kernel image
2057	  is decompressed and the virtual address where the kernel
2058	  image is mapped, as a security feature that deters exploit
2059	  attempts relying on knowledge of the location of kernel
2060	  code internals.
2061
2062	  On 64-bit, the kernel physical and virtual addresses are
2063	  randomized separately. The physical address will be anywhere
2064	  between 16MB and the top of physical memory (up to 64TB). The
2065	  virtual address will be randomized from 16MB up to 1GB (9 bits
2066	  of entropy). Note that this also reduces the memory space
2067	  available to kernel modules from 1.5GB to 1GB.
2068
2069	  On 32-bit, the kernel physical and virtual addresses are
2070	  randomized together. They will be randomized from 16MB up to
2071	  512MB (8 bits of entropy).
2072
2073	  Entropy is generated using the RDRAND instruction if it is
2074	  supported. If RDTSC is supported, its value is mixed into
2075	  the entropy pool as well. If neither RDRAND nor RDTSC are
2076	  supported, then entropy is read from the i8254 timer. The
2077	  usable entropy is limited by the kernel being built using
2078	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2079	  minimum of 2MB. As a result, only 10 bits of entropy are
2080	  theoretically possible, but the implementations are further
2081	  limited due to memory layouts.
2082
2083	  If unsure, say Y.
2084
2085# Relocation on x86 needs some additional build support
2086config X86_NEED_RELOCS
2087	def_bool y
2088	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2089	select ARCH_VMLINUX_NEEDS_RELOCS
2090
2091config PHYSICAL_ALIGN
2092	hex "Alignment value to which kernel should be aligned"
2093	default "0x200000"
2094	range 0x2000 0x1000000 if X86_32
2095	range 0x200000 0x1000000 if X86_64
2096	help
2097	  This value puts the alignment restrictions on physical address
2098	  where kernel is loaded and run from. Kernel is compiled for an
2099	  address which meets above alignment restriction.
2100
2101	  If bootloader loads the kernel at a non-aligned address and
2102	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2103	  address aligned to above value and run from there.
2104
2105	  If bootloader loads the kernel at a non-aligned address and
2106	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2107	  load address and decompress itself to the address it has been
2108	  compiled for and run from there. The address for which kernel is
2109	  compiled already meets above alignment restrictions. Hence the
2110	  end result is that kernel runs from a physical address meeting
2111	  above alignment restrictions.
2112
2113	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2114	  this value must be a multiple of 0x200000.
2115
2116	  Don't change this unless you know what you are doing.
2117
2118config RANDOMIZE_MEMORY
2119	bool "Randomize the kernel memory sections"
2120	depends on X86_64
2121	depends on RANDOMIZE_BASE
2122	default RANDOMIZE_BASE
2123	help
2124	  Randomizes the base virtual address of kernel memory sections
2125	  (physical memory mapping, vmalloc & vmemmap). This security feature
2126	  makes exploits relying on predictable memory locations less reliable.
2127
2128	  The order of allocations remains unchanged. Entropy is generated in
2129	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2130	  configuration have in average 30,000 different possible virtual
2131	  addresses for each memory section.
2132
2133	  If unsure, say Y.
2134
2135config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2136	hex "Physical memory mapping padding" if EXPERT
2137	depends on RANDOMIZE_MEMORY
2138	default "0xa" if MEMORY_HOTPLUG
2139	default "0x0"
2140	range 0x1 0x40 if MEMORY_HOTPLUG
2141	range 0x0 0x40
2142	help
2143	  Define the padding in terabytes added to the existing physical
2144	  memory size during kernel memory randomization. It is useful
2145	  for memory hotplug support but reduces the entropy available for
2146	  address randomization.
2147
2148	  If unsure, leave at the default value.
2149
2150config ADDRESS_MASKING
2151	bool "Linear Address Masking support"
2152	depends on X86_64
2153	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2154	help
2155	  Linear Address Masking (LAM) modifies the checking that is applied
2156	  to 64-bit linear addresses, allowing software to use of the
2157	  untranslated address bits for metadata.
2158
2159	  The capability can be used for efficient address sanitizers (ASAN)
2160	  implementation and for optimizations in JITs.
2161
2162config HOTPLUG_CPU
2163	def_bool y
2164	depends on SMP
2165
2166config COMPAT_VDSO
2167	def_bool n
2168	prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)"
2169	depends on COMPAT_32
2170	help
2171	  Certain buggy versions of glibc will crash if they are
2172	  presented with a 32-bit vDSO that is not mapped at the address
2173	  indicated in its segment table.
2174
2175	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2176	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2177	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2178	  the only released version with the bug, but OpenSUSE 9
2179	  contains a buggy "glibc 2.3.2".
2180
2181	  The symptom of the bug is that everything crashes on startup, saying:
2182	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2183
2184	  Saying Y here changes the default value of the vdso32 boot
2185	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2186	  This works around the glibc bug but hurts performance.
2187
2188	  If unsure, say N: if you are compiling your own kernel, you
2189	  are unlikely to be using a buggy version of glibc.
2190
2191choice
2192	prompt "vsyscall table for legacy applications"
2193	depends on X86_64
2194	default LEGACY_VSYSCALL_XONLY
2195	help
2196	  Legacy user code that does not know how to find the vDSO expects
2197	  to be able to issue three syscalls by calling fixed addresses in
2198	  kernel space. Since this location is not randomized with ASLR,
2199	  it can be used to assist security vulnerability exploitation.
2200
2201	  This setting can be changed at boot time via the kernel command
2202	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2203	  is deprecated and can only be enabled using the kernel command
2204	  line.
2205
2206	  On a system with recent enough glibc (2.14 or newer) and no
2207	  static binaries, you can say None without a performance penalty
2208	  to improve security.
2209
2210	  If unsure, select "Emulate execution only".
2211
2212	config LEGACY_VSYSCALL_XONLY
2213		bool "Emulate execution only"
2214		help
2215		  The kernel traps and emulates calls into the fixed vsyscall
2216		  address mapping and does not allow reads.  This
2217		  configuration is recommended when userspace might use the
2218		  legacy vsyscall area but support for legacy binary
2219		  instrumentation of legacy code is not needed.  It mitigates
2220		  certain uses of the vsyscall area as an ASLR-bypassing
2221		  buffer.
2222
2223	config LEGACY_VSYSCALL_NONE
2224		bool "None"
2225		help
2226		  There will be no vsyscall mapping at all. This will
2227		  eliminate any risk of ASLR bypass due to the vsyscall
2228		  fixed address mapping. Attempts to use the vsyscalls
2229		  will be reported to dmesg, so that either old or
2230		  malicious userspace programs can be identified.
2231
2232endchoice
2233
2234config CMDLINE_BOOL
2235	bool "Built-in kernel command line"
2236	help
2237	  Allow for specifying boot arguments to the kernel at
2238	  build time.  On some systems (e.g. embedded ones), it is
2239	  necessary or convenient to provide some or all of the
2240	  kernel boot arguments with the kernel itself (that is,
2241	  to not rely on the boot loader to provide them.)
2242
2243	  To compile command line arguments into the kernel,
2244	  set this option to 'Y', then fill in the
2245	  boot arguments in CONFIG_CMDLINE.
2246
2247	  Systems with fully functional boot loaders (i.e. non-embedded)
2248	  should leave this option set to 'N'.
2249
2250config CMDLINE
2251	string "Built-in kernel command string"
2252	depends on CMDLINE_BOOL
2253	default ""
2254	help
2255	  Enter arguments here that should be compiled into the kernel
2256	  image and used at boot time.  If the boot loader provides a
2257	  command line at boot time, it is appended to this string to
2258	  form the full kernel command line, when the system boots.
2259
2260	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2261	  change this behavior.
2262
2263	  In most cases, the command line (whether built-in or provided
2264	  by the boot loader) should specify the device for the root
2265	  file system.
2266
2267config CMDLINE_OVERRIDE
2268	bool "Built-in command line overrides boot loader arguments"
2269	depends on CMDLINE_BOOL && CMDLINE != ""
2270	help
2271	  Set this option to 'Y' to have the kernel ignore the boot loader
2272	  command line, and use ONLY the built-in command line.
2273
2274	  This is used to work around broken boot loaders.  This should
2275	  be set to 'N' under normal conditions.
2276
2277config MODIFY_LDT_SYSCALL
2278	bool "Enable the LDT (local descriptor table)" if EXPERT
2279	default y
2280	help
2281	  Linux can allow user programs to install a per-process x86
2282	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2283	  call.  This is required to run 16-bit or segmented code such as
2284	  DOSEMU or some Wine programs.  It is also used by some very old
2285	  threading libraries.
2286
2287	  Enabling this feature adds a small amount of overhead to
2288	  context switches and increases the low-level kernel attack
2289	  surface.  Disabling it removes the modify_ldt(2) system call.
2290
2291	  Saying 'N' here may make sense for embedded or server kernels.
2292
2293config STRICT_SIGALTSTACK_SIZE
2294	bool "Enforce strict size checking for sigaltstack"
2295	depends on DYNAMIC_SIGFRAME
2296	help
2297	  For historical reasons MINSIGSTKSZ is a constant which became
2298	  already too small with AVX512 support. Add a mechanism to
2299	  enforce strict checking of the sigaltstack size against the
2300	  real size of the FPU frame. This option enables the check
2301	  by default. It can also be controlled via the kernel command
2302	  line option 'strict_sas_size' independent of this config
2303	  switch. Enabling it might break existing applications which
2304	  allocate a too small sigaltstack but 'work' because they
2305	  never get a signal delivered.
2306
2307	  Say 'N' unless you want to really enforce this check.
2308
2309config CFI_AUTO_DEFAULT
2310	bool "Attempt to use FineIBT by default at boot time"
2311	depends on FINEIBT
2312	depends on !RUST || RUSTC_VERSION >= 108800
2313	default y
2314	help
2315	  Attempt to use FineIBT by default at boot time. If enabled,
2316	  this is the same as booting with "cfi=auto". If disabled,
2317	  this is the same as booting with "cfi=kcfi".
2318
2319source "kernel/livepatch/Kconfig"
2320
2321config X86_BUS_LOCK_DETECT
2322	bool "Split Lock Detect and Bus Lock Detect support"
2323	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2324	default y
2325	help
2326	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2327	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2328
2329endmenu
2330
2331config CC_HAS_NAMED_AS
2332	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2333	depends on CC_IS_GCC
2334
2335#
2336# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2337# are incompatible with named address spaces with GCC < 13.3
2338# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2339#
2340
2341config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2342	def_bool y
2343	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2344	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2345
2346config USE_X86_SEG_SUPPORT
2347	def_bool CC_HAS_NAMED_AS
2348	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2349
2350config CC_HAS_SLS
2351	def_bool $(cc-option,-mharden-sls=all)
2352
2353config CC_HAS_RETURN_THUNK
2354	def_bool $(cc-option,-mfunction-return=thunk-extern)
2355
2356config CC_HAS_ENTRY_PADDING
2357	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2358
2359config CC_HAS_KCFI_ARITY
2360	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2361	depends on CC_IS_CLANG && !RUST
2362
2363config FUNCTION_PADDING_CFI
2364	int
2365	default 59 if FUNCTION_ALIGNMENT_64B
2366	default 27 if FUNCTION_ALIGNMENT_32B
2367	default 11 if FUNCTION_ALIGNMENT_16B
2368	default  3 if FUNCTION_ALIGNMENT_8B
2369	default  0
2370
2371# Basically: FUNCTION_ALIGNMENT - 5*CFI
2372# except Kconfig can't do arithmetic :/
2373config FUNCTION_PADDING_BYTES
2374	int
2375	default FUNCTION_PADDING_CFI if CFI
2376	default FUNCTION_ALIGNMENT
2377
2378config CALL_PADDING
2379	def_bool n
2380	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2381	select FUNCTION_ALIGNMENT_16B
2382
2383config FINEIBT
2384	def_bool y
2385	depends on X86_KERNEL_IBT && CFI && MITIGATION_RETPOLINE
2386	select CALL_PADDING
2387
2388config FINEIBT_BHI
2389	def_bool y
2390	depends on FINEIBT && CC_HAS_KCFI_ARITY
2391
2392config HAVE_CALL_THUNKS
2393	def_bool y
2394	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2395
2396config CALL_THUNKS
2397	def_bool n
2398	select CALL_PADDING
2399
2400menuconfig CPU_MITIGATIONS
2401	bool "Mitigations for CPU vulnerabilities"
2402	default y
2403	help
2404	  Say Y here to enable options which enable mitigations for hardware
2405	  vulnerabilities (usually related to speculative execution).
2406	  Mitigations can be disabled or restricted to SMT systems at runtime
2407	  via the "mitigations" kernel parameter.
2408
2409	  If you say N, all mitigations will be disabled.  This CANNOT be
2410	  overridden at runtime.
2411
2412	  Say 'Y', unless you really know what you are doing.
2413
2414if CPU_MITIGATIONS
2415
2416config MITIGATION_PAGE_TABLE_ISOLATION
2417	bool "Remove the kernel mapping in user mode"
2418	default y
2419	depends on (X86_64 || X86_PAE)
2420	help
2421	  This feature reduces the number of hardware side channels by
2422	  ensuring that the majority of kernel addresses are not mapped
2423	  into userspace.
2424
2425	  See Documentation/arch/x86/pti.rst for more details.
2426
2427config MITIGATION_RETPOLINE
2428	bool "Avoid speculative indirect branches in kernel"
2429	select OBJTOOL if HAVE_OBJTOOL
2430	default y
2431	help
2432	  Compile kernel with the retpoline compiler options to guard against
2433	  kernel-to-user data leaks by avoiding speculative indirect
2434	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2435	  support for full protection. The kernel may run slower.
2436
2437config MITIGATION_RETHUNK
2438	bool "Enable return-thunks"
2439	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2440	select OBJTOOL if HAVE_OBJTOOL
2441	default y if X86_64
2442	help
2443	  Compile the kernel with the return-thunks compiler option to guard
2444	  against kernel-to-user data leaks by avoiding return speculation.
2445	  Requires a compiler with -mfunction-return=thunk-extern
2446	  support for full protection. The kernel may run slower.
2447
2448config MITIGATION_UNRET_ENTRY
2449	bool "Enable UNRET on kernel entry"
2450	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2451	default y
2452	help
2453	  Compile the kernel with support for the retbleed=unret mitigation.
2454
2455config MITIGATION_CALL_DEPTH_TRACKING
2456	bool "Mitigate RSB underflow with call depth tracking"
2457	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2458	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2459	select CALL_THUNKS
2460	default y
2461	help
2462	  Compile the kernel with call depth tracking to mitigate the Intel
2463	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2464	  by default and needs to be enabled on the kernel command line via the
2465	  retbleed=stuff option. For non-affected systems the overhead of this
2466	  option is marginal as the call depth tracking is using run-time
2467	  generated call thunks in a compiler generated padding area and call
2468	  patching. This increases text size by ~5%. For non affected systems
2469	  this space is unused. On affected SKL systems this results in a
2470	  significant performance gain over the IBRS mitigation.
2471
2472config CALL_THUNKS_DEBUG
2473	bool "Enable call thunks and call depth tracking debugging"
2474	depends on MITIGATION_CALL_DEPTH_TRACKING
2475	select FUNCTION_ALIGNMENT_32B
2476	default n
2477	help
2478	  Enable call/ret counters for imbalance detection and build in
2479	  a noisy dmesg about callthunks generation and call patching for
2480	  trouble shooting. The debug prints need to be enabled on the
2481	  kernel command line with 'debug-callthunks'.
2482	  Only enable this when you are debugging call thunks as this
2483	  creates a noticeable runtime overhead. If unsure say N.
2484
2485config MITIGATION_IBPB_ENTRY
2486	bool "Enable IBPB on kernel entry"
2487	depends on CPU_SUP_AMD && X86_64
2488	default y
2489	help
2490	  Compile the kernel with support for the retbleed=ibpb and
2491	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2492
2493config MITIGATION_IBRS_ENTRY
2494	bool "Enable IBRS on kernel entry"
2495	depends on CPU_SUP_INTEL && X86_64
2496	default y
2497	help
2498	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2499	  This mitigates both spectre_v2 and retbleed at great cost to
2500	  performance.
2501
2502config MITIGATION_SRSO
2503	bool "Mitigate speculative RAS overflow on AMD"
2504	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2505	default y
2506	help
2507	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2508
2509config MITIGATION_SLS
2510	bool "Mitigate Straight-Line-Speculation"
2511	depends on CC_HAS_SLS && X86_64
2512	select OBJTOOL if HAVE_OBJTOOL
2513	default n
2514	help
2515	  Compile the kernel with straight-line-speculation options to guard
2516	  against straight line speculation. The kernel image might be slightly
2517	  larger.
2518
2519config MITIGATION_GDS
2520	bool "Mitigate Gather Data Sampling"
2521	depends on CPU_SUP_INTEL
2522	default y
2523	help
2524	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2525	  vulnerability which allows unprivileged speculative access to data
2526	  which was previously stored in vector registers. The attacker uses gather
2527	  instructions to infer the stale vector register data.
2528
2529config MITIGATION_RFDS
2530	bool "RFDS Mitigation"
2531	depends on CPU_SUP_INTEL
2532	default y
2533	help
2534	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2535	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2536	  allows unprivileged speculative access to stale data previously
2537	  stored in floating point, vector and integer registers.
2538	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2539
2540config MITIGATION_SPECTRE_BHI
2541	bool "Mitigate Spectre-BHB (Branch History Injection)"
2542	depends on CPU_SUP_INTEL
2543	default y
2544	help
2545	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2546	  where the branch history buffer is poisoned to speculatively steer
2547	  indirect branches.
2548	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2549
2550config MITIGATION_MDS
2551	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2552	depends on CPU_SUP_INTEL
2553	default y
2554	help
2555	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2556	  a hardware vulnerability which allows unprivileged speculative access
2557	  to data which is available in various CPU internal buffers.
2558	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2559
2560config MITIGATION_TAA
2561	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2562	depends on CPU_SUP_INTEL
2563	default y
2564	help
2565	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2566	  vulnerability that allows unprivileged speculative access to data
2567	  which is available in various CPU internal buffers by using
2568	  asynchronous aborts within an Intel TSX transactional region.
2569	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2570
2571config MITIGATION_MMIO_STALE_DATA
2572	bool "Mitigate MMIO Stale Data hardware bug"
2573	depends on CPU_SUP_INTEL
2574	default y
2575	help
2576	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2577	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2578	  vulnerabilities that can expose data. The vulnerabilities require the
2579	  attacker to have access to MMIO.
2580	  See also
2581	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2582
2583config MITIGATION_L1TF
2584	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2585	depends on CPU_SUP_INTEL
2586	default y
2587	help
2588	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2589	  hardware vulnerability which allows unprivileged speculative access to data
2590	  available in the Level 1 Data Cache.
2591	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2592
2593config MITIGATION_RETBLEED
2594	bool "Mitigate RETBleed hardware bug"
2595	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2596	default y
2597	help
2598	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2599	  with Return Instructions) vulnerability.  RETBleed is a speculative
2600	  execution attack which takes advantage of microarchitectural behavior
2601	  in many modern microprocessors, similar to Spectre v2. An
2602	  unprivileged attacker can use these flaws to bypass conventional
2603	  memory security restrictions to gain read access to privileged memory
2604	  that would otherwise be inaccessible.
2605
2606config MITIGATION_SPECTRE_V1
2607	bool "Mitigate SPECTRE V1 hardware bug"
2608	default y
2609	help
2610	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2611	  class of side channel attacks that takes advantage of speculative
2612	  execution that bypasses conditional branch instructions used for
2613	  memory access bounds check.
2614	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2615
2616config MITIGATION_SPECTRE_V2
2617	bool "Mitigate SPECTRE V2 hardware bug"
2618	default y
2619	help
2620	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2621	  V2 is a class of side channel attacks that takes advantage of
2622	  indirect branch predictors inside the processor. In Spectre variant 2
2623	  attacks, the attacker can steer speculative indirect branches in the
2624	  victim to gadget code by poisoning the branch target buffer of a CPU
2625	  used for predicting indirect branch addresses.
2626	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2627
2628config MITIGATION_SRBDS
2629	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2630	depends on CPU_SUP_INTEL
2631	default y
2632	help
2633	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2634	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2635	  Sampling (MDS) techniques to infer values returned from special
2636	  register accesses. An unprivileged user can extract values returned
2637	  from RDRAND and RDSEED executed on another core or sibling thread
2638	  using MDS techniques.
2639	  See also
2640	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2641
2642config MITIGATION_SSB
2643	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2644	default y
2645	help
2646	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2647	  hardware security vulnerability and its exploitation takes advantage
2648	  of speculative execution in a similar way to the Meltdown and Spectre
2649	  security vulnerabilities.
2650
2651config MITIGATION_ITS
2652	bool "Enable Indirect Target Selection mitigation"
2653	depends on CPU_SUP_INTEL && X86_64
2654	depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK
2655	select EXECMEM
2656	default y
2657	help
2658	  Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in
2659	  BPU on some Intel CPUs that may allow Spectre V2 style attacks. If
2660	  disabled, mitigation cannot be enabled via cmdline.
2661	  See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst>
2662
2663config MITIGATION_TSA
2664	bool "Mitigate Transient Scheduler Attacks"
2665	depends on CPU_SUP_AMD
2666	default y
2667	help
2668	  Enable mitigation for Transient Scheduler Attacks. TSA is a hardware
2669	  security vulnerability on AMD CPUs which can lead to forwarding of
2670	  invalid info to subsequent instructions and thus can affect their
2671	  timing and thereby cause a leakage.
2672
2673config MITIGATION_VMSCAPE
2674	bool "Mitigate VMSCAPE"
2675	depends on KVM
2676	default y
2677	help
2678	  Enable mitigation for VMSCAPE attacks. VMSCAPE is a hardware security
2679	  vulnerability on Intel and AMD CPUs that may allow a guest to do
2680	  Spectre v2 style attacks on userspace hypervisor.
2681endif
2682
2683config ARCH_HAS_ADD_PAGES
2684	def_bool y
2685	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2686
2687menu "Power management and ACPI options"
2688
2689config ARCH_HIBERNATION_HEADER
2690	def_bool y
2691	depends on HIBERNATION
2692
2693source "kernel/power/Kconfig"
2694
2695source "drivers/acpi/Kconfig"
2696
2697config X86_APM_BOOT
2698	def_bool y
2699	depends on APM
2700
2701menuconfig APM
2702	tristate "APM (Advanced Power Management) BIOS support"
2703	depends on X86_32 && PM_SLEEP
2704	help
2705	  APM is a BIOS specification for saving power using several different
2706	  techniques. This is mostly useful for battery powered laptops with
2707	  APM compliant BIOSes. If you say Y here, the system time will be
2708	  reset after a RESUME operation, the /proc/apm device will provide
2709	  battery status information, and user-space programs will receive
2710	  notification of APM "events" (e.g. battery status change).
2711
2712	  If you select "Y" here, you can disable actual use of the APM
2713	  BIOS by passing the "apm=off" option to the kernel at boot time.
2714
2715	  Note that the APM support is almost completely disabled for
2716	  machines with more than one CPU.
2717
2718	  In order to use APM, you will need supporting software. For location
2719	  and more information, read <file:Documentation/power/apm-acpi.rst>
2720	  and the Battery Powered Linux mini-HOWTO, available from
2721	  <http://www.tldp.org/docs.html#howto>.
2722
2723	  This driver does not spin down disk drives (see the hdparm(8)
2724	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2725	  VESA-compliant "green" monitors.
2726
2727	  Generally, if you don't have a battery in your machine, there isn't
2728	  much point in using this driver and you should say N. If you get
2729	  random kernel OOPSes or reboots that don't seem to be related to
2730	  anything, try disabling/enabling this option (or disabling/enabling
2731	  APM in your BIOS).
2732
2733	  Some other things you should try when experiencing seemingly random,
2734	  "weird" problems:
2735
2736	  1) make sure that you have enough swap space and that it is
2737	  enabled.
2738	  2) pass the "idle=poll" option to the kernel
2739	  3) pass the "floppy=nodma" option to the kernel
2740	  4) pass the "mem=4M" option to the kernel (thereby disabling
2741	  all but the first 4 MB of RAM)
2742	  5) make sure that the CPU is not over clocked.
2743	  6) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2744	  7) disable the cache from your BIOS settings
2745	  8) install a fan for the video card or exchange video RAM
2746	  9) install a better fan for the CPU
2747	  10) exchange RAM chips
2748	  11) exchange the motherboard.
2749
2750	  To compile this driver as a module, choose M here: the
2751	  module will be called apm.
2752
2753if APM
2754
2755config APM_IGNORE_USER_SUSPEND
2756	bool "Ignore USER SUSPEND"
2757	help
2758	  This option will ignore USER SUSPEND requests. On machines with a
2759	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2760	  series notebooks, it is necessary to say Y because of a BIOS bug.
2761
2762config APM_DO_ENABLE
2763	bool "Enable PM at boot time"
2764	help
2765	  Enable APM features at boot time. From page 36 of the APM BIOS
2766	  specification: "When disabled, the APM BIOS does not automatically
2767	  power manage devices, enter the Standby State, enter the Suspend
2768	  State, or take power saving steps in response to CPU Idle calls."
2769	  This driver will make CPU Idle calls when Linux is idle (unless this
2770	  feature is turned off -- see "Do CPU IDLE calls", below). This
2771	  should always save battery power, but more complicated APM features
2772	  will be dependent on your BIOS implementation. You may need to turn
2773	  this option off if your computer hangs at boot time when using APM
2774	  support, or if it beeps continuously instead of suspending. Turn
2775	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2776	  T400CDT. This is off by default since most machines do fine without
2777	  this feature.
2778
2779config APM_CPU_IDLE
2780	depends on CPU_IDLE
2781	bool "Make CPU Idle calls when idle"
2782	help
2783	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2784	  On some machines, this can activate improved power savings, such as
2785	  a slowed CPU clock rate, when the machine is idle. These idle calls
2786	  are made after the idle loop has run for some length of time (e.g.,
2787	  333 mS). On some machines, this will cause a hang at boot time or
2788	  whenever the CPU becomes idle. (On machines with more than one CPU,
2789	  this option does nothing.)
2790
2791config APM_DISPLAY_BLANK
2792	bool "Enable console blanking using APM"
2793	help
2794	  Enable console blanking using the APM. Some laptops can use this to
2795	  turn off the LCD backlight when the screen blanker of the Linux
2796	  virtual console blanks the screen. Note that this is only used by
2797	  the virtual console screen blanker, and won't turn off the backlight
2798	  when using the X Window system. This also doesn't have anything to
2799	  do with your VESA-compliant power-saving monitor. Further, this
2800	  option doesn't work for all laptops -- it might not turn off your
2801	  backlight at all, or it might print a lot of errors to the console,
2802	  especially if you are using gpm.
2803
2804config APM_ALLOW_INTS
2805	bool "Allow interrupts during APM BIOS calls"
2806	help
2807	  Normally we disable external interrupts while we are making calls to
2808	  the APM BIOS as a measure to lessen the effects of a badly behaving
2809	  BIOS implementation.  The BIOS should reenable interrupts if it
2810	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2811	  many of the newer IBM Thinkpads.  If you experience hangs when you
2812	  suspend, try setting this to Y.  Otherwise, say N.
2813
2814endif # APM
2815
2816source "drivers/cpufreq/Kconfig"
2817
2818source "drivers/cpuidle/Kconfig"
2819
2820source "drivers/idle/Kconfig"
2821
2822endmenu
2823
2824menu "Bus options (PCI etc.)"
2825
2826choice
2827	prompt "PCI access mode"
2828	depends on X86_32 && PCI
2829	default PCI_GOANY
2830	help
2831	  On PCI systems, the BIOS can be used to detect the PCI devices and
2832	  determine their configuration. However, some old PCI motherboards
2833	  have BIOS bugs and may crash if this is done. Also, some embedded
2834	  PCI-based systems don't have any BIOS at all. Linux can also try to
2835	  detect the PCI hardware directly without using the BIOS.
2836
2837	  With this option, you can specify how Linux should detect the
2838	  PCI devices. If you choose "BIOS", the BIOS will be used,
2839	  if you choose "Direct", the BIOS won't be used, and if you
2840	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2841	  If you choose "Any", the kernel will try MMCONFIG, then the
2842	  direct access method and falls back to the BIOS if that doesn't
2843	  work. If unsure, go with the default, which is "Any".
2844
2845config PCI_GOBIOS
2846	bool "BIOS"
2847
2848config PCI_GOMMCONFIG
2849	bool "MMConfig"
2850
2851config PCI_GODIRECT
2852	bool "Direct"
2853
2854config PCI_GOOLPC
2855	bool "OLPC XO-1"
2856	depends on OLPC
2857
2858config PCI_GOANY
2859	bool "Any"
2860
2861endchoice
2862
2863config PCI_BIOS
2864	def_bool y
2865	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2866
2867# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2868config PCI_DIRECT
2869	def_bool y
2870	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2871
2872config PCI_MMCONFIG
2873	bool "Support mmconfig PCI config space access" if X86_64
2874	default y
2875	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2876	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2877	help
2878	  Add support for accessing the PCI configuration space as a memory
2879	  mapped area. It is the recommended method if the system supports
2880	  this (it must have PCI Express and ACPI for it to be available).
2881
2882	  In the unlikely case that enabling this configuration option causes
2883	  problems, the mechanism can be switched off with the 'pci=nommconf'
2884	  command line parameter.
2885
2886	  Say N only if you are sure that your platform does not support this
2887	  access method or you have problems caused by it.
2888
2889	  Say Y otherwise.
2890
2891config PCI_OLPC
2892	def_bool y
2893	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2894
2895config PCI_XEN
2896	def_bool y
2897	depends on PCI && XEN
2898
2899config MMCONF_FAM10H
2900	def_bool y
2901	depends on X86_64 && PCI_MMCONFIG && ACPI
2902
2903config PCI_CNB20LE_QUIRK
2904	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2905	depends on X86_32 && PCI
2906	help
2907	  Read the PCI windows out of the CNB20LE host bridge. This allows
2908	  PCI hotplug to work on systems with the CNB20LE chipset which do
2909	  not have ACPI.
2910
2911	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2912	  most probably only for Pentium III.
2913
2914	  To find out if you have such a chipset, search for a PCI device with
2915	  1166:0009 PCI IDs, for example by executing
2916		lspci -nn | grep '1166:0009'
2917	  The code is inactive if there is none.
2918
2919	  There's no public spec for this chipset, and this functionality
2920	  is known to be incomplete.
2921
2922	  You should say N unless you know you need this.
2923
2924config ISA_BUS
2925	bool "ISA bus support on modern systems" if EXPERT
2926	help
2927	  Expose ISA bus device drivers and options available for selection and
2928	  configuration. Enable this option if your target machine has an ISA
2929	  bus. ISA is an older system, displaced by PCI and newer bus
2930	  architectures -- if your target machine is modern, it probably does
2931	  not have an ISA bus.
2932
2933	  If unsure, say N.
2934
2935# x86_64 have no ISA slots, but can have ISA-style DMA.
2936config ISA_DMA_API
2937	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2938	default y
2939	help
2940	  Enables ISA-style DMA support for devices requiring such controllers.
2941	  If unsure, say Y.
2942
2943if X86_32
2944
2945config ISA
2946	bool "ISA support"
2947	help
2948	  Find out whether you have ISA slots on your motherboard.  ISA is the
2949	  name of a bus system, i.e. the way the CPU talks to the other stuff
2950	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2951	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2952	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2953
2954config SCx200
2955	tristate "NatSemi SCx200 support"
2956	help
2957	  This provides basic support for National Semiconductor's
2958	  (now AMD's) Geode processors.  The driver probes for the
2959	  PCI-IDs of several on-chip devices, so its a good dependency
2960	  for other scx200_* drivers.
2961
2962	  If compiled as a module, the driver is named scx200.
2963
2964config SCx200HR_TIMER
2965	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2966	depends on SCx200
2967	default y
2968	help
2969	  This driver provides a clocksource built upon the on-chip
2970	  27MHz high-resolution timer.  Its also a workaround for
2971	  NSC Geode SC-1100's buggy TSC, which loses time when the
2972	  processor goes idle (as is done by the scheduler).  The
2973	  other workaround is idle=poll boot option.
2974
2975config OLPC
2976	bool "One Laptop Per Child support"
2977	depends on !X86_PAE
2978	select GPIOLIB
2979	select OF
2980	select OF_PROMTREE
2981	select IRQ_DOMAIN
2982	select OLPC_EC
2983	help
2984	  Add support for detecting the unique features of the OLPC
2985	  XO hardware.
2986
2987config OLPC_XO1_PM
2988	bool "OLPC XO-1 Power Management"
2989	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2990	help
2991	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2992
2993config OLPC_XO1_RTC
2994	bool "OLPC XO-1 Real Time Clock"
2995	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2996	help
2997	  Add support for the XO-1 real time clock, which can be used as a
2998	  programmable wakeup source.
2999
3000config OLPC_XO1_SCI
3001	bool "OLPC XO-1 SCI extras"
3002	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3003	depends on INPUT=y
3004	select POWER_SUPPLY
3005	help
3006	  Add support for SCI-based features of the OLPC XO-1 laptop:
3007	   - EC-driven system wakeups
3008	   - Power button
3009	   - Ebook switch
3010	   - Lid switch
3011	   - AC adapter status updates
3012	   - Battery status updates
3013
3014config OLPC_XO15_SCI
3015	bool "OLPC XO-1.5 SCI extras"
3016	depends on OLPC && ACPI
3017	select POWER_SUPPLY
3018	help
3019	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3020	   - EC-driven system wakeups
3021	   - AC adapter status updates
3022	   - Battery status updates
3023
3024config GEODE_COMMON
3025	bool
3026
3027config ALIX
3028	bool "PCEngines ALIX System Support (LED setup)"
3029	select GPIOLIB
3030	select GEODE_COMMON
3031	help
3032	  This option enables system support for the PCEngines ALIX.
3033	  At present this just sets up LEDs for GPIO control on
3034	  ALIX2/3/6 boards.  However, other system specific setup should
3035	  get added here.
3036
3037	  Note: You must still enable the drivers for GPIO and LED support
3038	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3039
3040	  Note: You have to set alix.force=1 for boards with Award BIOS.
3041
3042config NET5501
3043	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3044	select GPIOLIB
3045	select GEODE_COMMON
3046	help
3047	  This option enables system support for the Soekris Engineering net5501.
3048
3049config GEOS
3050	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3051	select GPIOLIB
3052	select GEODE_COMMON
3053	depends on DMI
3054	help
3055	  This option enables system support for the Traverse Technologies GEOS.
3056
3057config TS5500
3058	bool "Technologic Systems TS-5500 platform support"
3059	depends on MELAN
3060	select CHECK_SIGNATURE
3061	select NEW_LEDS
3062	select LEDS_CLASS
3063	help
3064	  This option enables system support for the Technologic Systems TS-5500.
3065
3066endif # X86_32
3067
3068config AMD_NB
3069	def_bool y
3070	depends on AMD_NODE
3071
3072config AMD_NODE
3073	def_bool y
3074	depends on CPU_SUP_AMD && PCI
3075
3076endmenu
3077
3078menu "Binary Emulations"
3079
3080config IA32_EMULATION
3081	bool "IA32 Emulation"
3082	depends on X86_64
3083	select ARCH_WANT_OLD_COMPAT_IPC
3084	select BINFMT_ELF
3085	select COMPAT_OLD_SIGACTION
3086	help
3087	  Include code to run legacy 32-bit programs under a
3088	  64-bit kernel. You should likely turn this on, unless you're
3089	  100% sure that you don't have any 32-bit programs left.
3090
3091config IA32_EMULATION_DEFAULT_DISABLED
3092	bool "IA32 emulation disabled by default"
3093	default n
3094	depends on IA32_EMULATION
3095	help
3096	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3097	  processes and access to 32-bit syscalls. If unsure, leave it to its
3098	  default value.
3099
3100config X86_X32_ABI
3101	bool "x32 ABI for 64-bit mode"
3102	depends on X86_64
3103	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3104	# compressed debug sections to x86_x32 properly:
3105	# https://github.com/ClangBuiltLinux/linux/issues/514
3106	# https://github.com/ClangBuiltLinux/linux/issues/1141
3107	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3108	help
3109	  Include code to run binaries for the x32 native 32-bit ABI
3110	  for 64-bit processors.  An x32 process gets access to the
3111	  full 64-bit register file and wide data path while leaving
3112	  pointers at 32 bits for smaller memory footprint.
3113
3114config COMPAT_32
3115	def_bool y
3116	depends on IA32_EMULATION || X86_32
3117	select HAVE_UID16
3118	select OLD_SIGSUSPEND3
3119
3120config COMPAT
3121	def_bool y
3122	depends on IA32_EMULATION || X86_X32_ABI
3123
3124config COMPAT_FOR_U64_ALIGNMENT
3125	def_bool y
3126	depends on COMPAT
3127
3128endmenu
3129
3130config HAVE_ATOMIC_IOMAP
3131	def_bool y
3132	depends on X86_32
3133
3134source "arch/x86/kvm/Kconfig"
3135
3136source "arch/x86/Kconfig.cpufeatures"
3137
3138source "arch/x86/Kconfig.assembler"
3139