xref: /linux/arch/x86/Kconfig (revision 589f41f2f08bb48e041b513e49f9f61eec232d64)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select HAVE_DEBUG_STACKOVERFLOW
18	select KMAP_LOCAL
19	select MODULES_USE_ELF_REL
20	select OLD_SIGACTION
21	select ARCH_SPLIT_ARG64
22
23config X86_64
24	def_bool y
25	depends on 64BIT
26	# Options that are inherently 64-bit kernel only:
27	select ARCH_HAS_GIGANTIC_PAGE
28	select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
29	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30	select ARCH_SUPPORTS_PER_VMA_LOCK
31	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
32	select HAVE_ARCH_SOFT_DIRTY
33	select MODULES_USE_ELF_RELA
34	select NEED_DMA_MAP_STATE
35	select SWIOTLB
36	select ARCH_HAS_ELFCORE_COMPAT
37	select ZONE_DMA32
38	select EXECMEM if DYNAMIC_FTRACE
39	select ACPI_MRRM if ACPI
40
41config FORCE_DYNAMIC_FTRACE
42	def_bool y
43	depends on X86_32
44	depends on FUNCTION_TRACER
45	select DYNAMIC_FTRACE
46	help
47	  We keep the static function tracing (!DYNAMIC_FTRACE) around
48	  in order to test the non static function tracing in the
49	  generic code, as other architectures still use it. But we
50	  only need to keep it around for x86_64. No need to keep it
51	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
52#
53# Arch settings
54#
55# ( Note that options that are marked 'if X86_64' could in principle be
56#   ported to 32-bit as well. )
57#
58config X86
59	def_bool y
60	#
61	# Note: keep this list sorted alphabetically
62	#
63	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
64	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
65	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
66	select ARCH_32BIT_OFF_T			if X86_32
67	select ARCH_CLOCKSOURCE_INIT
68	select ARCH_CONFIGURES_CPU_MITIGATIONS
69	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
70	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
71	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
72	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
73	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
74	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
75	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
76	select ARCH_HAS_CPU_ATTACK_VECTORS	if CPU_MITIGATIONS
77	select ARCH_HAS_CACHE_LINE_SIZE
78	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
79	select ARCH_HAS_CPU_FINALIZE_INIT
80	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
81	select ARCH_HAS_CURRENT_STACK_POINTER
82	select ARCH_HAS_DEBUG_VIRTUAL
83	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
84	select ARCH_HAS_DEVMEM_IS_ALLOWED
85	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
86	select ARCH_HAS_EARLY_DEBUG		if KGDB
87	select ARCH_HAS_ELF_RANDOMIZE
88	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
89	select ARCH_HAS_FAST_MULTIPLIER
90	select ARCH_HAS_FORTIFY_SOURCE
91	select ARCH_HAS_GCOV_PROFILE_ALL
92	select ARCH_HAS_KCOV			if X86_64
93	select ARCH_HAS_KERNEL_FPU_SUPPORT
94	select ARCH_HAS_MEM_ENCRYPT
95	select ARCH_HAS_MEMBARRIER_SYNC_CORE
96	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
97	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
98	select ARCH_HAS_PMEM_API		if X86_64
99	select ARCH_HAS_PREEMPT_LAZY
100	select ARCH_HAS_PTDUMP
101	select ARCH_HAS_PTE_SPECIAL
102	select ARCH_HAS_HW_PTE_YOUNG
103	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
104	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
105	select ARCH_HAS_COPY_MC			if X86_64
106	select ARCH_HAS_SET_MEMORY
107	select ARCH_HAS_SET_DIRECT_MAP
108	select ARCH_HAS_STRICT_KERNEL_RWX
109	select ARCH_HAS_STRICT_MODULE_RWX
110	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
111	select ARCH_HAS_SYSCALL_WRAPPER
112	select ARCH_HAS_UBSAN
113	select ARCH_HAS_DEBUG_WX
114	select ARCH_HAS_ZONE_DMA_SET if EXPERT
115	select ARCH_HAVE_NMI_SAFE_CMPXCHG
116	select ARCH_HAVE_EXTRA_ELF_NOTES
117	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
118	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
119	select ARCH_MIGHT_HAVE_PC_PARPORT
120	select ARCH_MIGHT_HAVE_PC_SERIO
121	select ARCH_STACKWALK
122	select ARCH_SUPPORTS_ACPI
123	select ARCH_SUPPORTS_ATOMIC_RMW
124	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
125	select ARCH_SUPPORTS_HUGETLBFS
126	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
127	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
128	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
129	select ARCH_SUPPORTS_CFI		if X86_64
130	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI
131	select ARCH_SUPPORTS_LTO_CLANG
132	select ARCH_SUPPORTS_LTO_CLANG_THIN
133	select ARCH_SUPPORTS_RT
134	select ARCH_SUPPORTS_AUTOFDO_CLANG
135	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
136	select ARCH_USE_BUILTIN_BSWAP
137	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CX8
138	select ARCH_USE_MEMTEST
139	select ARCH_USE_QUEUED_RWLOCKS
140	select ARCH_USE_QUEUED_SPINLOCKS
141	select ARCH_USE_SYM_ANNOTATIONS
142	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
143	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
144	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
145	select ARCH_WANTS_NO_INSTR
146	select ARCH_WANT_GENERAL_HUGETLB
147	select ARCH_WANT_HUGE_PMD_SHARE		if X86_64
148	select ARCH_WANT_LD_ORPHAN_WARN
149	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
150	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
151	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
152	select ARCH_WANTS_THP_SWAP		if X86_64
153	select ARCH_HAS_PARANOID_L1D_FLUSH
154	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
155	select BUILDTIME_TABLE_SORT
156	select CLKEVT_I8253
157	select CLOCKSOURCE_WATCHDOG
158	# Word-size accesses may read uninitialized data past the trailing \0
159	# in strings and cause false KMSAN reports.
160	select DCACHE_WORD_ACCESS		if !KMSAN
161	select DYNAMIC_SIGFRAME
162	select EDAC_ATOMIC_SCRUB
163	select EDAC_SUPPORT
164	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
165	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
166	select GENERIC_CLOCKEVENTS_MIN_ADJUST
167	select GENERIC_CMOS_UPDATE
168	select GENERIC_CPU_AUTOPROBE
169	select GENERIC_CPU_DEVICES
170	select GENERIC_CPU_VULNERABILITIES
171	select GENERIC_EARLY_IOREMAP
172	select GENERIC_ENTRY
173	select GENERIC_IOMAP
174	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
175	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
176	select GENERIC_IRQ_MIGRATION		if SMP
177	select GENERIC_IRQ_PROBE
178	select GENERIC_IRQ_RESERVATION_MODE
179	select GENERIC_IRQ_SHOW
180	select GENERIC_PENDING_IRQ		if SMP
181	select GENERIC_SMP_IDLE_THREAD
182	select GENERIC_TIME_VSYSCALL
183	select GENERIC_GETTIMEOFDAY
184	select GENERIC_VDSO_OVERFLOW_PROTECT
185	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
186	select HARDIRQS_SW_RESEND
187	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
188	select HAS_IOPORT
189	select HAVE_ACPI_APEI			if ACPI
190	select HAVE_ACPI_APEI_NMI		if ACPI
191	select HAVE_ALIGNED_STRUCT_PAGE
192	select HAVE_ARCH_AUDITSYSCALL
193	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
194	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
195	select HAVE_ARCH_JUMP_LABEL
196	select HAVE_ARCH_JUMP_LABEL_RELATIVE
197	select HAVE_ARCH_KASAN			if X86_64
198	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
199	select HAVE_ARCH_KFENCE
200	select HAVE_ARCH_KMSAN			if X86_64
201	select HAVE_ARCH_KGDB
202	select HAVE_ARCH_KSTACK_ERASE
203	select HAVE_ARCH_MMAP_RND_BITS		if MMU
204	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
205	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
206	select HAVE_ARCH_PREL32_RELOCATIONS
207	select HAVE_ARCH_SECCOMP_FILTER
208	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
209	select HAVE_ARCH_TRACEHOOK
210	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
211	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
212	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
213	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
214	select HAVE_ARCH_VMAP_STACK		if X86_64
215	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
216	select HAVE_ARCH_WITHIN_STACK_FRAMES
217	select HAVE_ASM_MODVERSIONS
218	select HAVE_CMPXCHG_DOUBLE
219	select HAVE_CMPXCHG_LOCAL
220	select HAVE_CONTEXT_TRACKING_USER		if X86_64
221	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
222	select HAVE_C_RECORDMCOUNT
223	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
224	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
225	select HAVE_BUILDTIME_MCOUNT_SORT
226	select HAVE_DEBUG_KMEMLEAK
227	select HAVE_DMA_CONTIGUOUS
228	select HAVE_DYNAMIC_FTRACE
229	select HAVE_DYNAMIC_FTRACE_WITH_REGS
230	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
231	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
232	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
233	select HAVE_DYNAMIC_FTRACE_WITH_JMP	if X86_64
234	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
235	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
236	select HAVE_EBPF_JIT
237	select HAVE_EFFICIENT_UNALIGNED_ACCESS
238	select HAVE_EISA			if X86_32
239	select HAVE_EXIT_THREAD
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_PT_RECLAIM		if X86_64
335	select ARCH_SUPPORTS_SCHED_SMT		if SMP
336	select SCHED_SMT			if SMP
337	select ARCH_SUPPORTS_SCHED_CLUSTER	if SMP
338	select ARCH_SUPPORTS_SCHED_MC		if SMP
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	  Note that if you say Y here and choose architecture "586" or
450	  "Pentium" under "Processor family", the kernel will not work on 486
451	  architectures. Similarly, multiprocessor kernels for the "PPro"
452	  architecture may not work on all Pentium based boards.
453
454	  People using multiprocessor machines who say Y here should also say
455	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
456	  Management" code will be disabled if you say Y here.
457
458	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
459	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
460	  <http://www.tldp.org/docs.html#howto>.
461
462	  If you don't know what to do here, say N.
463
464config X86_X2APIC
465	bool "x2APIC interrupt controller architecture support"
466	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
467	default y
468	help
469	  x2APIC is an interrupt controller architecture, a component of which
470	  (the local APIC) is present in the CPU. It allows faster access to
471	  the local APIC and supports a larger number of CPUs in the system
472	  than the predecessors.
473
474	  x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs
475	  in 2019, but it can be disabled by the BIOS. It is also frequently
476	  emulated in virtual machines, even when the host CPU does not support
477	  it. Support in the CPU can be checked by executing
478		grep x2apic /proc/cpuinfo
479
480	  If this configuration option is disabled, the kernel will boot with
481	  very reduced functionality and performance on some platforms that
482	  have x2APIC enabled. On the other hand, on hardware that does not
483	  support x2APIC, a kernel with this option enabled will just fallback
484	  to older APIC implementations.
485
486	  If in doubt, say Y.
487
488config AMD_SECURE_AVIC
489	bool "AMD Secure AVIC"
490	depends on AMD_MEM_ENCRYPT && X86_X2APIC
491	help
492	  Enable this to get AMD Secure AVIC support on guests that have this feature.
493
494	  AMD Secure AVIC provides hardware acceleration for performance sensitive
495	  APIC accesses and support for managing guest owned APIC state for SEV-SNP
496	  guests. Secure AVIC does not support xAPIC mode. It has functional
497	  dependency on x2apic being enabled in the guest.
498
499	  If you don't know what to do here, say N.
500
501config X86_POSTED_MSI
502	bool "Enable MSI and MSI-x delivery by posted interrupts"
503	depends on X86_64 && IRQ_REMAP
504	help
505	  This enables MSIs that are under interrupt remapping to be delivered as
506	  posted interrupts to the host kernel. Interrupt throughput can
507	  potentially be improved by coalescing CPU notifications during high
508	  frequency bursts.
509
510	  If you don't know what to do here, say N.
511
512config X86_MPPARSE
513	bool "Enable MPS table" if ACPI
514	default y
515	depends on X86_LOCAL_APIC
516	help
517	  For old smp systems that do not have proper acpi support. Newer systems
518	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
519
520config X86_CPU_RESCTRL
521	bool "x86 CPU resource control support"
522	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
523	depends on MISC_FILESYSTEMS
524	select ARCH_HAS_CPU_RESCTRL
525	select RESCTRL_FS
526	select RESCTRL_FS_PSEUDO_LOCK
527	help
528	  Enable x86 CPU resource control support.
529
530	  Provide support for the allocation and monitoring of system resources
531	  usage by the CPU.
532
533	  Intel calls this Intel Resource Director Technology
534	  (Intel(R) RDT). More information about RDT can be found in the
535	  Intel x86 Architecture Software Developer Manual.
536
537	  AMD calls this AMD Platform Quality of Service (AMD QoS).
538	  More information about AMD QoS can be found in the AMD64 Technology
539	  Platform Quality of Service Extensions manual.
540
541	  Say N if unsure.
542
543config X86_FRED
544	bool "Flexible Return and Event Delivery"
545	depends on X86_64
546	help
547	  When enabled, try to use Flexible Return and Event Delivery
548	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
549	  ring transitions and exception/interrupt handling if the
550	  system supports it.
551
552config X86_EXTENDED_PLATFORM
553	bool "Support for extended (non-PC) x86 platforms"
554	default y
555	help
556	  If you disable this option then the kernel will only support
557	  standard PC platforms. (which covers the vast majority of
558	  systems out there.)
559
560	  If you enable this option then you'll be able to select support
561	  for the following non-PC x86 platforms, depending on the value of
562	  CONFIG_64BIT.
563
564	  32-bit platforms (CONFIG_64BIT=n):
565		Goldfish (mostly Android emulator)
566		Intel CE media processor (CE4100) SoC
567		Intel Quark
568		RDC R-321x SoC
569
570	  64-bit platforms (CONFIG_64BIT=y):
571		Numascale NumaChip
572		ScaleMP vSMP
573		SGI Ultraviolet
574		Merrifield/Moorefield MID devices
575		Goldfish (mostly Android emulator)
576
577	  If you have one of these systems, or if you want to build a
578	  generic distribution kernel, say Y here - otherwise say N.
579
580# This is an alphabetically sorted list of 64 bit extended platforms
581# Please maintain the alphabetic order if and when there are additions
582config X86_NUMACHIP
583	bool "Numascale NumaChip"
584	depends on X86_64
585	depends on X86_EXTENDED_PLATFORM
586	depends on NUMA
587	depends on SMP
588	depends on X86_X2APIC
589	depends on PCI_MMCONFIG
590	help
591	  Adds support for Numascale NumaChip large-SMP systems. Needed to
592	  enable more than ~168 cores.
593	  If you don't have one of these, you should say N here.
594
595config X86_VSMP
596	bool "ScaleMP vSMP"
597	select HYPERVISOR_GUEST
598	select PARAVIRT
599	depends on X86_64 && PCI
600	depends on X86_EXTENDED_PLATFORM
601	depends on SMP
602	help
603	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
604	  supposed to run on these EM64T-based machines.  Only choose this option
605	  if you have one of these machines.
606
607config X86_UV
608	bool "SGI Ultraviolet"
609	depends on X86_64
610	depends on X86_EXTENDED_PLATFORM
611	depends on NUMA
612	depends on EFI
613	depends on KEXEC_CORE
614	depends on X86_X2APIC
615	depends on PCI
616	help
617	  This option is needed in order to support SGI Ultraviolet systems.
618	  If you don't have one of these, you should say N here.
619
620config X86_INTEL_MID
621	bool "Intel Z34xx/Z35xx MID platform support"
622	depends on X86_EXTENDED_PLATFORM
623	depends on X86_PLATFORM_DEVICES
624	depends on PCI
625	depends on X86_64 || (EXPERT && PCI_GOANY)
626	depends on X86_IO_APIC
627	select I2C
628	select DW_APB_TIMER
629	select INTEL_SCU_PCI
630	help
631	  Select to build a kernel capable of supporting 64-bit Intel MID
632	  (Mobile Internet Device) platform systems which do not have
633	  the PCI legacy interfaces.
634
635	  The only supported devices are the 22nm Merrified (Z34xx)
636	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
637	  a small number of Android devices such as the Asus Zenfone 2,
638	  Asus FonePad 8 and Dell Venue 7.
639
640	  If you are building for a PC class system or non-MID tablet
641	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
642
643	  Intel MID platforms are based on an Intel processor and chipset which
644	  consume less power than most of the x86 derivatives.
645
646config X86_GOLDFISH
647	bool "Goldfish (Virtual Platform)"
648	depends on X86_EXTENDED_PLATFORM
649	help
650	  Enable support for the Goldfish virtual platform used primarily
651	  for Android development. Unless you are building for the Android
652	  Goldfish emulator say N here.
653
654# Following is an alphabetically sorted list of 32 bit extended platforms
655# Please maintain the alphabetic order if and when there are additions
656
657config X86_INTEL_CE
658	bool "CE4100 TV platform"
659	depends on PCI
660	depends on PCI_GODIRECT
661	depends on X86_IO_APIC
662	depends on X86_32
663	depends on X86_EXTENDED_PLATFORM
664	select X86_REBOOTFIXUPS
665	select OF
666	select OF_EARLY_FLATTREE
667	help
668	  Select for the Intel CE media processor (CE4100) SOC.
669	  This option compiles in support for the CE4100 SOC for settop
670	  boxes and media devices.
671
672config X86_INTEL_QUARK
673	bool "Intel Quark platform support"
674	depends on X86_32
675	depends on X86_EXTENDED_PLATFORM
676	depends on X86_PLATFORM_DEVICES
677	depends on X86_TSC
678	depends on PCI
679	depends on PCI_GOANY
680	depends on X86_IO_APIC
681	select IOSF_MBI
682	select INTEL_IMR
683	select COMMON_CLK
684	help
685	  Select to include support for Quark X1000 SoC.
686	  Say Y here if you have a Quark based system such as the Arduino
687	  compatible Intel Galileo.
688
689config X86_RDC321X
690	bool "RDC R-321x SoC"
691	depends on X86_32
692	depends on X86_EXTENDED_PLATFORM
693	select M486
694	select X86_REBOOTFIXUPS
695	help
696	  This option is needed for RDC R-321x system-on-chip, also known
697	  as R-8610-(G).
698	  If you don't have one of these chips, you should say N here.
699
700config X86_INTEL_LPSS
701	bool "Intel Low Power Subsystem Support"
702	depends on X86 && ACPI && PCI
703	select COMMON_CLK
704	select PINCTRL
705	select IOSF_MBI
706	help
707	  Select to build support for Intel Low Power Subsystem such as
708	  found on Intel Lynxpoint PCH. Selecting this option enables
709	  things like clock tree (common clock framework) and pincontrol
710	  which are needed by the LPSS peripheral drivers.
711
712config X86_AMD_PLATFORM_DEVICE
713	bool "AMD ACPI2Platform devices support"
714	depends on ACPI
715	select COMMON_CLK
716	select PINCTRL
717	help
718	  Select to interpret AMD specific ACPI device to platform device
719	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
720	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
721	  implemented under PINCTRL subsystem.
722
723config IOSF_MBI
724	tristate "Intel SoC IOSF Sideband support for SoC platforms"
725	depends on PCI
726	help
727	  This option enables sideband register access support for Intel SoC
728	  platforms. On these platforms the IOSF sideband is used in lieu of
729	  MSR's for some register accesses, mostly but not limited to thermal
730	  and power. Drivers may query the availability of this device to
731	  determine if they need the sideband in order to work on these
732	  platforms. The sideband is available on the following SoC products.
733	  This list is not meant to be exclusive.
734	   - BayTrail
735	   - Braswell
736	   - Quark
737
738	  You should say Y if you are running a kernel on one of these SoC's.
739
740config IOSF_MBI_DEBUG
741	bool "Enable IOSF sideband access through debugfs"
742	depends on IOSF_MBI && DEBUG_FS
743	help
744	  Select this option to expose the IOSF sideband access registers (MCR,
745	  MDR, MCRX) through debugfs to write and read register information from
746	  different units on the SoC. This is most useful for obtaining device
747	  state information for debug and analysis. As this is a general access
748	  mechanism, users of this option would have specific knowledge of the
749	  device they want to access.
750
751	  If you don't require the option or are in doubt, say N.
752
753config X86_SUPPORTS_MEMORY_FAILURE
754	def_bool y
755	# MCE code calls memory_failure():
756	depends on X86_MCE
757	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
758	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
759	depends on X86_64 || !SPARSEMEM
760	select ARCH_SUPPORTS_MEMORY_FAILURE
761
762config X86_32_IRIS
763	tristate "Eurobraille/Iris poweroff module"
764	depends on X86_32
765	help
766	  The Iris machines from EuroBraille do not have APM or ACPI support
767	  to shut themselves down properly.  A special I/O sequence is
768	  needed to do so, which is what this module does at
769	  kernel shutdown.
770
771	  This is only for Iris machines from EuroBraille.
772
773	  If unused, say N.
774
775config SCHED_OMIT_FRAME_POINTER
776	def_bool y
777	prompt "Single-depth WCHAN output"
778	depends on X86
779	help
780	  Calculate simpler /proc/<PID>/wchan values. If this option
781	  is disabled then wchan values will recurse back to the
782	  caller function. This provides more accurate wchan values,
783	  at the expense of slightly more scheduling overhead.
784
785	  If in doubt, say "Y".
786
787menuconfig HYPERVISOR_GUEST
788	bool "Linux guest support"
789	help
790	  Say Y here to enable options for running Linux under various hyper-
791	  visors. This option enables basic hypervisor detection and platform
792	  setup.
793
794	  If you say N, all options in this submenu will be skipped and
795	  disabled, and Linux guest support won't be built in.
796
797if HYPERVISOR_GUEST
798
799config PARAVIRT
800	bool "Enable paravirtualization code"
801	depends on HAVE_STATIC_CALL
802	select HAVE_PV_STEAL_CLOCK_GEN
803	help
804	  This changes the kernel so it can modify itself when it is run
805	  under a hypervisor, potentially improving performance significantly
806	  over full virtualization.  However, when run without a hypervisor
807	  the kernel is theoretically slower and slightly larger.
808
809config PARAVIRT_XXL
810	bool
811	depends on X86_64
812
813config PARAVIRT_SPINLOCKS
814	bool "Paravirtualization layer for spinlocks"
815	depends on PARAVIRT && SMP
816	help
817	  Paravirtualized spinlocks allow a pvops backend to replace the
818	  spinlock implementation with something virtualization-friendly
819	  (for example, block the virtual CPU rather than spinning).
820
821	  It has a minimal impact on native kernels and gives a nice performance
822	  benefit on paravirtualized KVM / Xen kernels.
823
824	  If you are unsure how to answer this question, answer Y.
825
826config X86_HV_CALLBACK_VECTOR
827	def_bool n
828
829source "arch/x86/xen/Kconfig"
830
831config KVM_GUEST
832	bool "KVM Guest support (including kvmclock)"
833	depends on PARAVIRT
834	select PARAVIRT_CLOCK
835	select ARCH_CPUIDLE_HALTPOLL
836	select X86_HV_CALLBACK_VECTOR
837	default y
838	help
839	  This option enables various optimizations for running under the KVM
840	  hypervisor. It includes a paravirtualized clock, so that instead
841	  of relying on a PIT (or probably other) emulation by the
842	  underlying device model, the host provides the guest with
843	  timing infrastructure such as time of day, and system time
844
845config ARCH_CPUIDLE_HALTPOLL
846	def_bool n
847	prompt "Disable host haltpoll when loading haltpoll driver"
848	help
849	  If virtualized under KVM, disable host haltpoll.
850
851config PVH
852	bool "Support for running PVH guests"
853	help
854	  This option enables the PVH entry point for guest virtual machines
855	  as specified in the x86/HVM direct boot ABI.
856
857config PARAVIRT_TIME_ACCOUNTING
858	bool "Paravirtual steal time accounting"
859	depends on PARAVIRT
860	help
861	  Select this option to enable fine granularity task steal time
862	  accounting. Time spent executing other tasks in parallel with
863	  the current vCPU is discounted from the vCPU power. To account for
864	  that, there can be a small performance impact.
865
866	  If in doubt, say N here.
867
868config PARAVIRT_CLOCK
869	bool
870
871config JAILHOUSE_GUEST
872	bool "Jailhouse non-root cell support"
873	depends on X86_64 && PCI
874	select X86_PM_TIMER
875	help
876	  This option allows to run Linux as guest in a Jailhouse non-root
877	  cell. You can leave this option disabled if you only want to start
878	  Jailhouse and run Linux afterwards in the root cell.
879
880config ACRN_GUEST
881	bool "ACRN Guest support"
882	depends on X86_64
883	select X86_HV_CALLBACK_VECTOR
884	help
885	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
886	  a flexible, lightweight reference open-source hypervisor, built with
887	  real-time and safety-criticality in mind. It is built for embedded
888	  IOT with small footprint and real-time features. More details can be
889	  found in https://projectacrn.org/.
890
891config BHYVE_GUEST
892	bool "Bhyve (BSD Hypervisor) Guest support"
893	depends on X86_64
894	help
895	  This option allows to run Linux to recognise when it is running as a
896	  guest in the Bhyve hypervisor, and to support more than 255 vCPUs when
897	  when doing so. More details about Bhyve can be found at https://bhyve.org
898	  and https://wiki.freebsd.org/bhyve/.
899
900config INTEL_TDX_GUEST
901	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
902	depends on X86_64 && CPU_SUP_INTEL
903	depends on X86_X2APIC
904	depends on EFI_STUB
905	depends on PARAVIRT
906	select ARCH_HAS_CC_PLATFORM
907	select X86_MEM_ENCRYPT
908	select X86_MCE
909	select UNACCEPTED_MEMORY
910	help
911	  Support running as a guest under Intel TDX.  Without this support,
912	  the guest kernel can not boot or run under TDX.
913	  TDX includes memory encryption and integrity capabilities
914	  which protect the confidentiality and integrity of guest
915	  memory contents and CPU state. TDX guests are protected from
916	  some attacks from the VMM.
917
918endif # HYPERVISOR_GUEST
919
920source "arch/x86/Kconfig.cpu"
921
922config HPET_TIMER
923	def_bool X86_64
924	prompt "HPET Timer Support" if X86_32
925	help
926	  Use the IA-PC HPET (High Precision Event Timer) to manage
927	  time in preference to the PIT and RTC, if a HPET is
928	  present.
929	  HPET is the next generation timer replacing legacy 8254s.
930	  The HPET provides a stable time base on SMP
931	  systems, unlike the TSC, but it is more expensive to access,
932	  as it is off-chip.  The interface used is documented
933	  in the HPET spec, revision 1.
934
935	  You can safely choose Y here.  However, HPET will only be
936	  activated if the platform and the BIOS support this feature.
937	  Otherwise the 8254 will be used for timing services.
938
939	  Choose N to continue using the legacy 8254 timer.
940
941config HPET_EMULATE_RTC
942	def_bool y
943	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
944
945# Mark as expert because too many people got it wrong.
946# The code disables itself when not needed.
947config DMI
948	default y
949	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
950	bool "Enable DMI scanning" if EXPERT
951	help
952	  Enabled scanning of DMI to identify machine quirks. Say Y
953	  here unless you have verified that your setup is not
954	  affected by entries in the DMI blacklist. Required by PNP
955	  BIOS code.
956
957config GART_IOMMU
958	bool "Old AMD GART IOMMU support"
959	select IOMMU_HELPER
960	select SWIOTLB
961	depends on X86_64 && PCI && AMD_NB
962	help
963	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
964	  GART based hardware IOMMUs.
965
966	  The GART supports full DMA access for devices with 32-bit access
967	  limitations, on systems with more than 3 GB. This is usually needed
968	  for USB, sound, many IDE/SATA chipsets and some other devices.
969
970	  Newer systems typically have a modern AMD IOMMU, supported via
971	  the CONFIG_AMD_IOMMU=y config option.
972
973	  In normal configurations this driver is only active when needed:
974	  there's more than 3 GB of memory and the system contains a
975	  32-bit limited device.
976
977	  If unsure, say Y.
978
979config BOOT_VESA_SUPPORT
980	bool
981	help
982	  If true, at least one selected framebuffer driver can take advantage
983	  of VESA video modes set at an early boot stage via the vga= parameter.
984
985config MAXSMP
986	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
987	depends on X86_64 && SMP && DEBUG_KERNEL
988	select CPUMASK_OFFSTACK
989	help
990	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
991	  If unsure, say N.
992
993#
994# The maximum number of CPUs supported:
995#
996# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
997# and which can be configured interactively in the
998# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
999#
1000# The ranges are different on 32-bit and 64-bit kernels, depending on
1001# hardware capabilities and scalability features of the kernel.
1002#
1003# ( If MAXSMP is enabled we just use the highest possible value and disable
1004#   interactive configuration. )
1005#
1006
1007config NR_CPUS_RANGE_BEGIN
1008	int
1009	default NR_CPUS_RANGE_END if MAXSMP
1010	default    1 if !SMP
1011	default    2
1012
1013config NR_CPUS_RANGE_END
1014	int
1015	depends on X86_32
1016	default    8 if  SMP
1017	default    1 if !SMP
1018
1019config NR_CPUS_RANGE_END
1020	int
1021	depends on X86_64
1022	default 8192 if  SMP && CPUMASK_OFFSTACK
1023	default  512 if  SMP && !CPUMASK_OFFSTACK
1024	default    1 if !SMP
1025
1026config NR_CPUS_DEFAULT
1027	int
1028	depends on X86_32
1029	default    8 if  SMP
1030	default    1 if !SMP
1031
1032config NR_CPUS_DEFAULT
1033	int
1034	depends on X86_64
1035	default 8192 if  MAXSMP
1036	default   64 if  SMP
1037	default    1 if !SMP
1038
1039config NR_CPUS
1040	int "Maximum number of CPUs" if SMP && !MAXSMP
1041	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1042	default NR_CPUS_DEFAULT
1043	help
1044	  This allows you to specify the maximum number of CPUs which this
1045	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1046	  supported value is 8192, otherwise the maximum value is 512.  The
1047	  minimum value which makes sense is 2.
1048
1049	  This is purely to save memory: each supported CPU adds about 8KB
1050	  to the kernel image.
1051
1052config SCHED_MC_PRIO
1053	bool "CPU core priorities scheduler support"
1054	depends on SCHED_MC
1055	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1056	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1057	select CPU_FREQ
1058	default y
1059	help
1060	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1061	  core ordering determined at manufacturing time, which allows
1062	  certain cores to reach higher turbo frequencies (when running
1063	  single threaded workloads) than others.
1064
1065	  Enabling this kernel feature teaches the scheduler about
1066	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1067	  scheduler's CPU selection logic accordingly, so that higher
1068	  overall system performance can be achieved.
1069
1070	  This feature will have no effect on CPUs without this feature.
1071
1072	  If unsure say Y here.
1073
1074config UP_LATE_INIT
1075	def_bool y
1076	depends on !SMP && X86_LOCAL_APIC
1077
1078config X86_UP_APIC
1079	bool "Local APIC support on uniprocessors" if !PCI_MSI
1080	default PCI_MSI
1081	depends on X86_32 && !SMP
1082	help
1083	  A local APIC (Advanced Programmable Interrupt Controller) is an
1084	  integrated interrupt controller in the CPU. If you have a single-CPU
1085	  system which has a processor with a local APIC, you can say Y here to
1086	  enable and use it. If you say Y here even though your machine doesn't
1087	  have a local APIC, then the kernel will still run with no slowdown at
1088	  all. The local APIC supports CPU-generated self-interrupts (timer,
1089	  performance counters), and the NMI watchdog which detects hard
1090	  lockups.
1091
1092config X86_UP_IOAPIC
1093	bool "IO-APIC support on uniprocessors"
1094	depends on X86_UP_APIC
1095	help
1096	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1097	  SMP-capable replacement for PC-style interrupt controllers. Most
1098	  SMP systems and many recent uniprocessor systems have one.
1099
1100	  If you have a single-CPU system with an IO-APIC, you can say Y here
1101	  to use it. If you say Y here even though your machine doesn't have
1102	  an IO-APIC, then the kernel will still run with no slowdown at all.
1103
1104config X86_LOCAL_APIC
1105	def_bool y
1106	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1107	select IRQ_DOMAIN_HIERARCHY
1108
1109config ACPI_MADT_WAKEUP
1110	def_bool y
1111	depends on X86_64
1112	depends on ACPI
1113	depends on SMP
1114	depends on X86_LOCAL_APIC
1115
1116config X86_IO_APIC
1117	def_bool y
1118	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1119
1120config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1121	bool "Reroute for broken boot IRQs"
1122	depends on X86_IO_APIC
1123	help
1124	  This option enables a workaround that fixes a source of
1125	  spurious interrupts. This is recommended when threaded
1126	  interrupt handling is used on systems where the generation of
1127	  superfluous "boot interrupts" cannot be disabled.
1128
1129	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1130	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1131	  kernel does during interrupt handling). On chipsets where this
1132	  boot IRQ generation cannot be disabled, this workaround keeps
1133	  the original IRQ line masked so that only the equivalent "boot
1134	  IRQ" is delivered to the CPUs. The workaround also tells the
1135	  kernel to set up the IRQ handler on the boot IRQ line. In this
1136	  way only one interrupt is delivered to the kernel. Otherwise
1137	  the spurious second interrupt may cause the kernel to bring
1138	  down (vital) interrupt lines.
1139
1140	  Only affects "broken" chipsets. Interrupt sharing may be
1141	  increased on these systems.
1142
1143config X86_MCE
1144	bool "Machine Check / overheating reporting"
1145	select GENERIC_ALLOCATOR
1146	default y
1147	help
1148	  Machine Check support allows the processor to notify the
1149	  kernel if it detects a problem (e.g. overheating, data corruption).
1150	  The action the kernel takes depends on the severity of the problem,
1151	  ranging from warning messages to halting the machine.
1152
1153config X86_MCELOG_LEGACY
1154	bool "Support for deprecated /dev/mcelog character device"
1155	depends on X86_MCE
1156	help
1157	  Enable support for /dev/mcelog which is needed by the old mcelog
1158	  userspace logging daemon. Consider switching to the new generation
1159	  rasdaemon solution.
1160
1161config X86_MCE_INTEL
1162	def_bool y
1163	prompt "Intel MCE features"
1164	depends on X86_MCE && X86_LOCAL_APIC
1165	help
1166	  Additional support for intel specific MCE features such as
1167	  the thermal monitor.
1168
1169config X86_MCE_AMD
1170	def_bool y
1171	prompt "AMD MCE features"
1172	depends on X86_MCE && X86_LOCAL_APIC
1173	help
1174	  Additional support for AMD specific MCE features such as
1175	  the DRAM Error Threshold.
1176
1177config X86_ANCIENT_MCE
1178	bool "Support for old Pentium 5 / WinChip machine checks"
1179	depends on X86_32 && X86_MCE
1180	help
1181	  Include support for machine check handling on old Pentium 5 or WinChip
1182	  systems. These typically need to be enabled explicitly on the command
1183	  line.
1184
1185config X86_MCE_THRESHOLD
1186	depends on X86_MCE_AMD || X86_MCE_INTEL
1187	def_bool y
1188
1189config X86_MCE_INJECT
1190	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1191	tristate "Machine check injector support"
1192	help
1193	  Provide support for injecting machine checks for testing purposes.
1194	  If you don't know what a machine check is and you don't do kernel
1195	  QA it is safe to say n.
1196
1197source "arch/x86/events/Kconfig"
1198
1199config X86_LEGACY_VM86
1200	bool "Legacy VM86 support"
1201	depends on X86_32
1202	help
1203	  This option allows user programs to put the CPU into V8086
1204	  mode, which is an 80286-era approximation of 16-bit real mode.
1205
1206	  Some very old versions of X and/or vbetool require this option
1207	  for user mode setting.  Similarly, DOSEMU will use it if
1208	  available to accelerate real mode DOS programs.  However, any
1209	  recent version of DOSEMU, X, or vbetool should be fully
1210	  functional even without kernel VM86 support, as they will all
1211	  fall back to software emulation. Nevertheless, if you are using
1212	  a 16-bit DOS program where 16-bit performance matters, vm86
1213	  mode might be faster than emulation and you might want to
1214	  enable this option.
1215
1216	  Note that any app that works on a 64-bit kernel is unlikely to
1217	  need this option, as 64-bit kernels don't, and can't, support
1218	  V8086 mode. This option is also unrelated to 16-bit protected
1219	  mode and is not needed to run most 16-bit programs under Wine.
1220
1221	  Enabling this option increases the complexity of the kernel
1222	  and slows down exception handling a tiny bit.
1223
1224	  If unsure, say N here.
1225
1226config VM86
1227	bool
1228	default X86_LEGACY_VM86
1229
1230config X86_16BIT
1231	bool "Enable support for 16-bit segments" if EXPERT
1232	default y
1233	depends on MODIFY_LDT_SYSCALL
1234	help
1235	  This option is required by programs like Wine to run 16-bit
1236	  protected mode legacy code on x86 processors.  Disabling
1237	  this option saves about 300 bytes on i386, or around 6K text
1238	  plus 16K runtime memory on x86-64,
1239
1240config X86_ESPFIX32
1241	def_bool y
1242	depends on X86_16BIT && X86_32
1243
1244config X86_ESPFIX64
1245	def_bool y
1246	depends on X86_16BIT && X86_64
1247
1248config X86_VSYSCALL_EMULATION
1249	bool "Enable vsyscall emulation" if EXPERT
1250	default y
1251	depends on X86_64
1252	help
1253	  This enables emulation of the legacy vsyscall page.  Disabling
1254	  it is roughly equivalent to booting with vsyscall=none, except
1255	  that it will also disable the helpful warning if a program
1256	  tries to use a vsyscall.  With this option set to N, offending
1257	  programs will just segfault, citing addresses of the form
1258	  0xffffffffff600?00.
1259
1260	  This option is required by many programs built before 2013, and
1261	  care should be used even with newer programs if set to N.
1262
1263	  Disabling this option saves about 7K of kernel size and
1264	  possibly 4K of additional runtime pagetable memory.
1265
1266config X86_IOPL_IOPERM
1267	bool "IOPERM and IOPL Emulation"
1268	default y
1269	help
1270	  This enables the ioperm() and iopl() syscalls which are necessary
1271	  for legacy applications.
1272
1273	  Legacy IOPL support is an overbroad mechanism which allows user
1274	  space aside of accessing all 65536 I/O ports also to disable
1275	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1276	  capabilities and permission from potentially active security
1277	  modules.
1278
1279	  The emulation restricts the functionality of the syscall to
1280	  only allowing the full range I/O port access, but prevents the
1281	  ability to disable interrupts from user space which would be
1282	  granted if the hardware IOPL mechanism would be used.
1283
1284config TOSHIBA
1285	tristate "Toshiba Laptop support"
1286	depends on X86_32
1287	help
1288	  This adds a driver to safely access the System Management Mode of
1289	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1290	  not work on models with a Phoenix BIOS. The System Management Mode
1291	  is used to set the BIOS and power saving options on Toshiba portables.
1292
1293	  For information on utilities to make use of this driver see the
1294	  Toshiba Linux utilities web site at:
1295	  <http://www.buzzard.org.uk/toshiba/>.
1296
1297	  Say Y if you intend to run this kernel on a Toshiba portable.
1298	  Say N otherwise.
1299
1300config X86_REBOOTFIXUPS
1301	bool "Enable X86 board specific fixups for reboot"
1302	depends on X86_32
1303	help
1304	  This enables chipset and/or board specific fixups to be done
1305	  in order to get reboot to work correctly. This is only needed on
1306	  some combinations of hardware and BIOS. The symptom, for which
1307	  this config is intended, is when reboot ends with a stalled/hung
1308	  system.
1309
1310	  Currently, the only fixup is for the Geode machines using
1311	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1312
1313	  Say Y if you want to enable the fixup. Currently, it's safe to
1314	  enable this option even if you don't need it.
1315	  Say N otherwise.
1316
1317config MICROCODE
1318	def_bool y
1319	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1320	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1321
1322config MICROCODE_INITRD32
1323	def_bool y
1324	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1325
1326config MICROCODE_LATE_LOADING
1327	bool "Late microcode loading (DANGEROUS)"
1328	default n
1329	depends on MICROCODE && SMP
1330	help
1331	  Loading microcode late, when the system is up and executing instructions
1332	  is a tricky business and should be avoided if possible. Just the sequence
1333	  of synchronizing all cores and SMT threads is one fragile dance which does
1334	  not guarantee that cores might not softlock after the loading. Therefore,
1335	  use this at your own risk. Late loading taints the kernel unless the
1336	  microcode header indicates that it is safe for late loading via the
1337	  minimal revision check. This minimal revision check can be enforced on
1338	  the kernel command line with "microcode=force_minrev".
1339
1340config MICROCODE_LATE_FORCE_MINREV
1341	bool "Enforce late microcode loading minimal revision check"
1342	default n
1343	depends on MICROCODE_LATE_LOADING
1344	help
1345	  To prevent that users load microcode late which modifies already
1346	  in use features, newer microcode patches have a minimum revision field
1347	  in the microcode header, which tells the kernel which minimum
1348	  revision must be active in the CPU to safely load that new microcode
1349	  late into the running system. If disabled the check will not
1350	  be enforced but the kernel will be tainted when the minimal
1351	  revision check fails.
1352
1353	  This minimal revision check can also be controlled via the
1354	  "microcode=force_minrev" parameter on the kernel command line.
1355
1356	  If unsure say Y.
1357
1358config MICROCODE_DBG
1359	bool "Enable microcode loader debugging"
1360	default n
1361	depends on MICROCODE
1362	help
1363	  Enable code which allows for debugging the microcode loader in
1364	  a guest. Meaning the patch loading is simulated but everything else
1365	  related to patch parsing and handling is done as on baremetal with
1366	  the purpose of debugging solely the software side of things.
1367
1368	  You almost certainly want to say n here.
1369
1370config X86_MSR
1371	tristate "/dev/cpu/*/msr - Model-specific register support"
1372	help
1373	  This device gives privileged processes access to the x86
1374	  Model-Specific Registers (MSRs).  It is a character device with
1375	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1376	  MSR accesses are directed to a specific CPU on multi-processor
1377	  systems.
1378
1379config X86_CPUID
1380	tristate "/dev/cpu/*/cpuid - CPU information support"
1381	help
1382	  This device gives processes access to the x86 CPUID instruction to
1383	  be executed on a specific processor.  It is a character device
1384	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1385	  /dev/cpu/31/cpuid.
1386
1387config HIGHMEM4G
1388	bool "High Memory Support"
1389	depends on X86_32
1390	help
1391	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1392	  However, the address space of 32-bit x86 processors is only 4
1393	  Gigabytes large. That means that, if you have a large amount of
1394	  physical memory, not all of it can be "permanently mapped" by the
1395	  kernel. The physical memory that's not permanently mapped is called
1396	  "high memory".
1397
1398	  If you are compiling a kernel which will never run on a machine with
1399	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1400	  choice and suitable for most users). This will result in a "3GB/1GB"
1401	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1402	  space and the remaining part of the 4GB virtual memory space is used
1403	  by the kernel to permanently map as much physical memory as
1404	  possible.
1405
1406	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1407	  answer "Y" here.
1408
1409	  If unsure, say N.
1410
1411choice
1412	prompt "Memory split" if EXPERT
1413	default VMSPLIT_3G
1414	depends on X86_32
1415	help
1416	  Select the desired split between kernel and user memory.
1417
1418	  If the address range available to the kernel is less than the
1419	  physical memory installed, the remaining memory will be available
1420	  as "high memory". Accessing high memory is a little more costly
1421	  than low memory, as it needs to be mapped into the kernel first.
1422	  Note that increasing the kernel address space limits the range
1423	  available to user programs, making the address space there
1424	  tighter.  Selecting anything other than the default 3G/1G split
1425	  will also likely make your kernel incompatible with binary-only
1426	  kernel modules.
1427
1428	  If you are not absolutely sure what you are doing, leave this
1429	  option alone!
1430
1431	config VMSPLIT_3G
1432		bool "3G/1G user/kernel split"
1433	config VMSPLIT_3G_OPT
1434		depends on !X86_PAE
1435		bool "3G/1G user/kernel split (for full 1G low memory)"
1436	config VMSPLIT_2G
1437		bool "2G/2G user/kernel split"
1438	config VMSPLIT_2G_OPT
1439		depends on !X86_PAE
1440		bool "2G/2G user/kernel split (for full 2G low memory)"
1441	config VMSPLIT_1G
1442		bool "1G/3G user/kernel split"
1443endchoice
1444
1445config PAGE_OFFSET
1446	hex
1447	default 0xB0000000 if VMSPLIT_3G_OPT
1448	default 0x80000000 if VMSPLIT_2G
1449	default 0x78000000 if VMSPLIT_2G_OPT
1450	default 0x40000000 if VMSPLIT_1G
1451	default 0xC0000000
1452	depends on X86_32
1453
1454config HIGHMEM
1455	def_bool HIGHMEM4G
1456
1457config X86_PAE
1458	bool "PAE (Physical Address Extension) Support"
1459	depends on X86_32 && X86_HAVE_PAE
1460	select PHYS_ADDR_T_64BIT
1461	help
1462	  PAE is required for NX support, and furthermore enables
1463	  larger swapspace support for non-overcommit purposes. It
1464	  has the cost of more pagetable lookup overhead, and also
1465	  consumes more pagetable space per process.
1466
1467config X86_DIRECT_GBPAGES
1468	def_bool y
1469	depends on X86_64
1470	help
1471	  Certain kernel features effectively disable kernel
1472	  linear 1 GB mappings (even if the CPU otherwise
1473	  supports them), so don't confuse the user by printing
1474	  that we have them enabled.
1475
1476config X86_CPA_STATISTICS
1477	bool "Enable statistic for Change Page Attribute"
1478	depends on DEBUG_FS
1479	help
1480	  Expose statistics about the Change Page Attribute mechanism, which
1481	  helps to determine the effectiveness of preserving large and huge
1482	  page mappings when mapping protections are changed.
1483
1484config X86_MEM_ENCRYPT
1485	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1486	select DYNAMIC_PHYSICAL_MASK
1487	def_bool n
1488
1489config AMD_MEM_ENCRYPT
1490	bool "AMD Secure Memory Encryption (SME) support"
1491	depends on X86_64 && CPU_SUP_AMD
1492	depends on EFI_STUB
1493	select DMA_COHERENT_POOL
1494	select ARCH_USE_MEMREMAP_PROT
1495	select INSTRUCTION_DECODER
1496	select ARCH_HAS_CC_PLATFORM
1497	select X86_MEM_ENCRYPT
1498	select UNACCEPTED_MEMORY
1499	select CRYPTO_LIB_AESGCM
1500	help
1501	  Say yes to enable support for the encryption of system memory.
1502	  This requires an AMD processor that supports Secure Memory
1503	  Encryption (SME).
1504
1505# Common NUMA Features
1506config NUMA
1507	bool "NUMA Memory Allocation and Scheduler Support"
1508	depends on SMP
1509	depends on X86_64
1510	select USE_PERCPU_NUMA_NODE_ID
1511	select OF_NUMA if OF
1512	help
1513	  Enable NUMA (Non-Uniform Memory Access) support.
1514
1515	  The kernel will try to allocate memory used by a CPU on the
1516	  local memory controller of the CPU and add some more
1517	  NUMA awareness to the kernel.
1518
1519	  For 64-bit this is recommended if the system is Intel Core i7
1520	  (or later), AMD Opteron, or EM64T NUMA.
1521
1522	  Otherwise, you should say N.
1523
1524config AMD_NUMA
1525	def_bool y
1526	prompt "Old style AMD Opteron NUMA detection"
1527	depends on X86_64 && NUMA && PCI
1528	help
1529	  Enable AMD NUMA node topology detection.  You should say Y here if
1530	  you have a multi processor AMD system. This uses an old method to
1531	  read the NUMA configuration directly from the builtin Northbridge
1532	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1533	  which also takes priority if both are compiled in.
1534
1535config X86_64_ACPI_NUMA
1536	def_bool y
1537	prompt "ACPI NUMA detection"
1538	depends on X86_64 && NUMA && ACPI && PCI
1539	select ACPI_NUMA
1540	help
1541	  Enable ACPI SRAT based node topology detection.
1542
1543config NODES_SHIFT
1544	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1545	range 1 10
1546	default "10" if MAXSMP
1547	default "6" if X86_64
1548	default "3"
1549	depends on NUMA
1550	help
1551	  Specify the maximum number of NUMA Nodes available on the target
1552	  system.  Increases memory reserved to accommodate various tables.
1553
1554config ARCH_FLATMEM_ENABLE
1555	def_bool y
1556	depends on X86_32 && !NUMA
1557
1558config ARCH_SPARSEMEM_ENABLE
1559	def_bool y
1560	select SPARSEMEM_STATIC if X86_32
1561	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1562
1563config ARCH_SPARSEMEM_DEFAULT
1564	def_bool X86_64 || (NUMA && X86_32)
1565
1566config ARCH_SELECT_MEMORY_MODEL
1567	def_bool y
1568	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1569
1570config ARCH_MEMORY_PROBE
1571	bool "Enable sysfs memory/probe interface"
1572	depends on MEMORY_HOTPLUG
1573	help
1574	  This option enables a sysfs memory/probe interface for testing.
1575	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1576	  If you are unsure how to answer this question, answer N.
1577
1578config ARCH_PROC_KCORE_TEXT
1579	def_bool y
1580	depends on X86_64 && PROC_KCORE
1581
1582config ILLEGAL_POINTER_VALUE
1583	hex
1584	default 0 if X86_32
1585	default 0xdead000000000000 if X86_64
1586
1587config X86_PMEM_LEGACY_DEVICE
1588	bool
1589
1590config X86_PMEM_LEGACY
1591	tristate "Support non-standard NVDIMMs and ADR protected memory"
1592	depends on PHYS_ADDR_T_64BIT
1593	depends on BLK_DEV
1594	select X86_PMEM_LEGACY_DEVICE
1595	select NUMA_KEEP_MEMINFO if NUMA
1596	select LIBNVDIMM
1597	help
1598	  Treat memory marked using the non-standard e820 type of 12 as used
1599	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1600	  The kernel will offer these regions to the 'pmem' driver so
1601	  they can be used for persistent storage.
1602
1603	  Say Y if unsure.
1604
1605config X86_CHECK_BIOS_CORRUPTION
1606	bool "Check for low memory corruption"
1607	help
1608	  Periodically check for memory corruption in low memory, which
1609	  is suspected to be caused by BIOS.  Even when enabled in the
1610	  configuration, it is disabled at runtime.  Enable it by
1611	  setting "memory_corruption_check=1" on the kernel command
1612	  line.  By default it scans the low 64k of memory every 60
1613	  seconds; see the memory_corruption_check_size and
1614	  memory_corruption_check_period parameters in
1615	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1616
1617	  When enabled with the default parameters, this option has
1618	  almost no overhead, as it reserves a relatively small amount
1619	  of memory and scans it infrequently.  It both detects corruption
1620	  and prevents it from affecting the running system.
1621
1622	  It is, however, intended as a diagnostic tool; if repeatable
1623	  BIOS-originated corruption always affects the same memory,
1624	  you can use memmap= to prevent the kernel from using that
1625	  memory.
1626
1627config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1628	bool "Set the default setting of memory_corruption_check"
1629	depends on X86_CHECK_BIOS_CORRUPTION
1630	default y
1631	help
1632	  Set whether the default state of memory_corruption_check is
1633	  on or off.
1634
1635config MATH_EMULATION
1636	bool
1637	depends on MODIFY_LDT_SYSCALL
1638	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1639	help
1640	  Linux can emulate a math coprocessor (used for floating point
1641	  operations) if you don't have one. 486DX and Pentium processors have
1642	  a math coprocessor built in, 486SX and 386 do not, unless you added
1643	  a 487DX or 387, respectively. (The messages during boot time can
1644	  give you some hints here ["man dmesg"].) Everyone needs either a
1645	  coprocessor or this emulation.
1646
1647	  If you don't have a math coprocessor, you need to say Y here; if you
1648	  say Y here even though you have a coprocessor, the coprocessor will
1649	  be used nevertheless. (This behavior can be changed with the kernel
1650	  command line option "no387", which comes handy if your coprocessor
1651	  is broken. Try "man bootparam" or see the documentation of your boot
1652	  loader (lilo or loadlin) about how to pass options to the kernel at
1653	  boot time.) This means that it is a good idea to say Y here if you
1654	  intend to use this kernel on different machines.
1655
1656	  More information about the internals of the Linux math coprocessor
1657	  emulation can be found in <file:arch/x86/math-emu/README>.
1658
1659	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1660	  kernel, it won't hurt.
1661
1662config MTRR
1663	def_bool y
1664	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1665	help
1666	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1667	  the Memory Type Range Registers (MTRRs) may be used to control
1668	  processor access to memory ranges. This is most useful if you have
1669	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1670	  allows bus write transfers to be combined into a larger transfer
1671	  before bursting over the PCI/AGP bus. This can increase performance
1672	  of image write operations 2.5 times or more. Saying Y here creates a
1673	  /proc/mtrr file which may be used to manipulate your processor's
1674	  MTRRs. Typically the X server should use this.
1675
1676	  This code has a reasonably generic interface so that similar
1677	  control registers on other processors can be easily supported
1678	  as well:
1679
1680	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1681	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1682	  these, the ARRs are used to emulate the MTRRs.
1683	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1684	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1685	  write-combining. All of these processors are supported by this code
1686	  and it makes sense to say Y here if you have one of them.
1687
1688	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1689	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1690	  can lead to all sorts of problems, so it's good to say Y here.
1691
1692	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1693	  just add about 9 KB to your kernel.
1694
1695	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1696
1697config MTRR_SANITIZER
1698	def_bool y
1699	prompt "MTRR cleanup support"
1700	depends on MTRR
1701	help
1702	  Convert MTRR layout from continuous to discrete, so X drivers can
1703	  add writeback entries.
1704
1705	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1706	  The largest mtrr entry size for a continuous block can be set with
1707	  mtrr_chunk_size.
1708
1709	  If unsure, say Y.
1710
1711config MTRR_SANITIZER_ENABLE_DEFAULT
1712	int "MTRR cleanup enable value (0-1)"
1713	range 0 1
1714	default "0"
1715	depends on MTRR_SANITIZER
1716	help
1717	  Enable mtrr cleanup default value
1718
1719config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1720	int "MTRR cleanup spare reg num (0-7)"
1721	range 0 7
1722	default "1"
1723	depends on MTRR_SANITIZER
1724	help
1725	  mtrr cleanup spare entries default, it can be changed via
1726	  mtrr_spare_reg_nr=N on the kernel command line.
1727
1728config X86_PAT
1729	def_bool y
1730	prompt "x86 PAT support" if EXPERT
1731	depends on MTRR
1732	select ARCH_USES_PG_ARCH_2
1733	help
1734	  Use PAT attributes to setup page level cache control.
1735
1736	  PATs are the modern equivalents of MTRRs and are much more
1737	  flexible than MTRRs.
1738
1739	  Say N here if you see bootup problems (boot crash, boot hang,
1740	  spontaneous reboots) or a non-working video driver.
1741
1742	  If unsure, say Y.
1743
1744config X86_UMIP
1745	def_bool y
1746	prompt "User Mode Instruction Prevention" if EXPERT
1747	help
1748	  User Mode Instruction Prevention (UMIP) is a security feature in
1749	  some x86 processors. If enabled, a general protection fault is
1750	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1751	  executed in user mode. These instructions unnecessarily expose
1752	  information about the hardware state.
1753
1754	  The vast majority of applications do not use these instructions.
1755	  For the very few that do, software emulation is provided in
1756	  specific cases in protected and virtual-8086 modes. Emulated
1757	  results are dummy.
1758
1759config CC_HAS_IBT
1760	# GCC >= 9 and binutils >= 2.29
1761	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1762	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || CC_IS_CLANG) && \
1763		  $(as-instr,endbr64)
1764
1765config X86_CET
1766	def_bool n
1767	help
1768	  CET features configured (Shadow stack or IBT)
1769
1770config X86_KERNEL_IBT
1771	prompt "Indirect Branch Tracking"
1772	def_bool y
1773	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1774	select OBJTOOL
1775	select X86_CET
1776	help
1777	  Build the kernel with support for Indirect Branch Tracking, a
1778	  hardware support course-grain forward-edge Control Flow Integrity
1779	  protection. It enforces that all indirect calls must land on
1780	  an ENDBR instruction, as such, the compiler will instrument the
1781	  code with them to make this happen.
1782
1783	  In addition to building the kernel with IBT, seal all functions that
1784	  are not indirect call targets, avoiding them ever becoming one.
1785
1786	  This requires LTO like objtool runs and will slow down the build. It
1787	  does significantly reduce the number of ENDBR instructions in the
1788	  kernel image.
1789
1790config X86_INTEL_MEMORY_PROTECTION_KEYS
1791	prompt "Memory Protection Keys"
1792	def_bool y
1793	# Note: only available in 64-bit mode
1794	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1795	select ARCH_USES_HIGH_VMA_FLAGS
1796	select ARCH_HAS_PKEYS
1797	help
1798	  Memory Protection Keys provides a mechanism for enforcing
1799	  page-based protections, but without requiring modification of the
1800	  page tables when an application changes protection domains.
1801
1802	  For details, see Documentation/core-api/protection-keys.rst
1803
1804	  If unsure, say y.
1805
1806config ARCH_PKEY_BITS
1807	int
1808	default 4
1809
1810choice
1811	prompt "TSX enable mode"
1812	depends on CPU_SUP_INTEL
1813	default X86_INTEL_TSX_MODE_OFF
1814	help
1815	  Intel's TSX (Transactional Synchronization Extensions) feature
1816	  allows to optimize locking protocols through lock elision which
1817	  can lead to a noticeable performance boost.
1818
1819	  On the other hand it has been shown that TSX can be exploited
1820	  to form side channel attacks (e.g. TAA) and chances are there
1821	  will be more of those attacks discovered in the future.
1822
1823	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1824	  might override this decision by tsx=on the command line parameter.
1825	  Even with TSX enabled, the kernel will attempt to enable the best
1826	  possible TAA mitigation setting depending on the microcode available
1827	  for the particular machine.
1828
1829	  This option allows to set the default tsx mode between tsx=on, =off
1830	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1831	  details.
1832
1833	  Say off if not sure, auto if TSX is in use but it should be used on safe
1834	  platforms or on if TSX is in use and the security aspect of tsx is not
1835	  relevant.
1836
1837config X86_INTEL_TSX_MODE_OFF
1838	bool "off"
1839	help
1840	  TSX is disabled if possible - equals to tsx=off command line parameter.
1841
1842config X86_INTEL_TSX_MODE_ON
1843	bool "on"
1844	help
1845	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1846	  line parameter.
1847
1848config X86_INTEL_TSX_MODE_AUTO
1849	bool "auto"
1850	help
1851	  TSX is enabled on TSX capable HW that is believed to be safe against
1852	  side channel attacks- equals the tsx=auto command line parameter.
1853endchoice
1854
1855config X86_SGX
1856	bool "Software Guard eXtensions (SGX)"
1857	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1858	select CRYPTO_LIB_SHA256
1859	select MMU_NOTIFIER
1860	select NUMA_KEEP_MEMINFO if NUMA
1861	select XARRAY_MULTI
1862	help
1863	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1864	  that can be used by applications to set aside private regions of code
1865	  and data, referred to as enclaves. An enclave's private memory can
1866	  only be accessed by code running within the enclave. Accesses from
1867	  outside the enclave, including other enclaves, are disallowed by
1868	  hardware.
1869
1870	  If unsure, say N.
1871
1872config X86_USER_SHADOW_STACK
1873	bool "X86 userspace shadow stack"
1874	depends on AS_WRUSS
1875	depends on X86_64
1876	select ARCH_USES_HIGH_VMA_FLAGS
1877	select ARCH_HAS_USER_SHADOW_STACK
1878	select X86_CET
1879	help
1880	  Shadow stack protection is a hardware feature that detects function
1881	  return address corruption.  This helps mitigate ROP attacks.
1882	  Applications must be enabled to use it, and old userspace does not
1883	  get protection "for free".
1884
1885	  CPUs supporting shadow stacks were first released in 2020.
1886
1887	  See Documentation/arch/x86/shstk.rst for more information.
1888
1889	  If unsure, say N.
1890
1891config INTEL_TDX_HOST
1892	bool "Intel Trust Domain Extensions (TDX) host support"
1893	depends on CPU_SUP_INTEL
1894	depends on X86_64
1895	depends on KVM_INTEL
1896	depends on X86_X2APIC
1897	select ARCH_KEEP_MEMBLOCK
1898	depends on CONTIG_ALLOC
1899	depends on X86_MCE
1900	help
1901	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1902	  host and certain physical attacks.  This option enables necessary TDX
1903	  support in the host kernel to run confidential VMs.
1904
1905	  If unsure, say N.
1906
1907config EFI
1908	bool "EFI runtime service support"
1909	depends on ACPI
1910	select UCS2_STRING
1911	select EFI_RUNTIME_WRAPPERS
1912	select ARCH_USE_MEMREMAP_PROT
1913	select EFI_RUNTIME_MAP if KEXEC_CORE
1914	help
1915	  This enables the kernel to use EFI runtime services that are
1916	  available (such as the EFI variable services).
1917
1918	  This option is only useful on systems that have EFI firmware.
1919	  In addition, you should use the latest ELILO loader available
1920	  at <http://elilo.sourceforge.net> in order to take advantage
1921	  of EFI runtime services. However, even with this option, the
1922	  resultant kernel should continue to boot on existing non-EFI
1923	  platforms.
1924
1925config EFI_STUB
1926	bool "EFI stub support"
1927	depends on EFI
1928	select RELOCATABLE
1929	help
1930	  This kernel feature allows a bzImage to be loaded directly
1931	  by EFI firmware without the use of a bootloader.
1932
1933	  See Documentation/admin-guide/efi-stub.rst for more information.
1934
1935config EFI_HANDOVER_PROTOCOL
1936	bool "EFI handover protocol (DEPRECATED)"
1937	depends on EFI_STUB
1938	default y
1939	help
1940	  Select this in order to include support for the deprecated EFI
1941	  handover protocol, which defines alternative entry points into the
1942	  EFI stub.  This is a practice that has no basis in the UEFI
1943	  specification, and requires a priori knowledge on the part of the
1944	  bootloader about Linux/x86 specific ways of passing the command line
1945	  and initrd, and where in memory those assets may be loaded.
1946
1947	  If in doubt, say Y. Even though the corresponding support is not
1948	  present in upstream GRUB or other bootloaders, most distros build
1949	  GRUB with numerous downstream patches applied, and may rely on the
1950	  handover protocol as as result.
1951
1952config EFI_MIXED
1953	bool "EFI mixed-mode support"
1954	depends on EFI_STUB && X86_64
1955	help
1956	  Enabling this feature allows a 64-bit kernel to be booted
1957	  on a 32-bit firmware, provided that your CPU supports 64-bit
1958	  mode.
1959
1960	  Note that it is not possible to boot a mixed-mode enabled
1961	  kernel via the EFI boot stub - a bootloader that supports
1962	  the EFI handover protocol must be used.
1963
1964	  If unsure, say N.
1965
1966config EFI_RUNTIME_MAP
1967	bool "Export EFI runtime maps to sysfs" if EXPERT
1968	depends on EFI
1969	help
1970	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1971	  That memory map is required by the 2nd kernel to set up EFI virtual
1972	  mappings after kexec, but can also be used for debugging purposes.
1973
1974	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1975
1976source "kernel/Kconfig.hz"
1977
1978config ARCH_SUPPORTS_KEXEC
1979	def_bool y
1980
1981config ARCH_SUPPORTS_KEXEC_FILE
1982	def_bool X86_64
1983
1984config ARCH_SELECTS_KEXEC_FILE
1985	def_bool y
1986	depends on KEXEC_FILE
1987	select HAVE_IMA_KEXEC if IMA
1988
1989config ARCH_SUPPORTS_KEXEC_PURGATORY
1990	def_bool y
1991
1992config ARCH_SUPPORTS_KEXEC_SIG
1993	def_bool y
1994
1995config ARCH_SUPPORTS_KEXEC_SIG_FORCE
1996	def_bool y
1997
1998config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
1999	def_bool y
2000
2001config ARCH_SUPPORTS_KEXEC_JUMP
2002	def_bool y
2003
2004config ARCH_SUPPORTS_KEXEC_HANDOVER
2005	def_bool X86_64
2006
2007config ARCH_SUPPORTS_CRASH_DUMP
2008	def_bool X86_64 || (X86_32 && HIGHMEM)
2009
2010config ARCH_DEFAULT_CRASH_DUMP
2011	def_bool y
2012
2013config ARCH_SUPPORTS_CRASH_HOTPLUG
2014	def_bool y
2015
2016config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2017	def_bool CRASH_RESERVE
2018
2019config PHYSICAL_START
2020	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2021	default "0x1000000"
2022	help
2023	  This gives the physical address where the kernel is loaded.
2024
2025	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2026	  will decompress itself to above physical address and run from there.
2027	  Otherwise, bzImage will run from the address where it has been loaded
2028	  by the boot loader. The only exception is if it is loaded below the
2029	  above physical address, in which case it will relocate itself there.
2030
2031	  In normal kdump cases one does not have to set/change this option
2032	  as now bzImage can be compiled as a completely relocatable image
2033	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2034	  address. This option is mainly useful for the folks who don't want
2035	  to use a bzImage for capturing the crash dump and want to use a
2036	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2037	  to be specifically compiled to run from a specific memory area
2038	  (normally a reserved region) and this option comes handy.
2039
2040	  So if you are using bzImage for capturing the crash dump,
2041	  leave the value here unchanged to 0x1000000 and set
2042	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2043	  for capturing the crash dump change this value to start of
2044	  the reserved region.  In other words, it can be set based on
2045	  the "X" value as specified in the "crashkernel=YM@XM"
2046	  command line boot parameter passed to the panic-ed
2047	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2048	  for more details about crash dumps.
2049
2050	  Usage of bzImage for capturing the crash dump is recommended as
2051	  one does not have to build two kernels. Same kernel can be used
2052	  as production kernel and capture kernel. Above option should have
2053	  gone away after relocatable bzImage support is introduced. But it
2054	  is present because there are users out there who continue to use
2055	  vmlinux for dump capture. This option should go away down the
2056	  line.
2057
2058	  Don't change this unless you know what you are doing.
2059
2060config RELOCATABLE
2061	bool "Build a relocatable kernel"
2062	default y
2063	help
2064	  This builds a kernel image that retains relocation information
2065	  so it can be loaded someplace besides the default 1MB.
2066	  The relocations tend to make the kernel binary about 10% larger,
2067	  but are discarded at runtime.
2068
2069	  One use is for the kexec on panic case where the recovery kernel
2070	  must live at a different physical address than the primary
2071	  kernel.
2072
2073	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2074	  it has been loaded at and the compile time physical address
2075	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2076
2077config RANDOMIZE_BASE
2078	bool "Randomize the address of the kernel image (KASLR)"
2079	depends on RELOCATABLE
2080	default y
2081	help
2082	  In support of Kernel Address Space Layout Randomization (KASLR),
2083	  this randomizes the physical address at which the kernel image
2084	  is decompressed and the virtual address where the kernel
2085	  image is mapped, as a security feature that deters exploit
2086	  attempts relying on knowledge of the location of kernel
2087	  code internals.
2088
2089	  On 64-bit, the kernel physical and virtual addresses are
2090	  randomized separately. The physical address will be anywhere
2091	  between 16MB and the top of physical memory (up to 64TB). The
2092	  virtual address will be randomized from 16MB up to 1GB (9 bits
2093	  of entropy). Note that this also reduces the memory space
2094	  available to kernel modules from 1.5GB to 1GB.
2095
2096	  On 32-bit, the kernel physical and virtual addresses are
2097	  randomized together. They will be randomized from 16MB up to
2098	  512MB (8 bits of entropy).
2099
2100	  Entropy is generated using the RDRAND instruction if it is
2101	  supported. If RDTSC is supported, its value is mixed into
2102	  the entropy pool as well. If neither RDRAND nor RDTSC are
2103	  supported, then entropy is read from the i8254 timer. The
2104	  usable entropy is limited by the kernel being built using
2105	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2106	  minimum of 2MB. As a result, only 10 bits of entropy are
2107	  theoretically possible, but the implementations are further
2108	  limited due to memory layouts.
2109
2110	  If unsure, say Y.
2111
2112# Relocation on x86 needs some additional build support
2113config X86_NEED_RELOCS
2114	def_bool y
2115	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2116	select ARCH_VMLINUX_NEEDS_RELOCS
2117
2118config PHYSICAL_ALIGN
2119	hex "Alignment value to which kernel should be aligned"
2120	default "0x200000"
2121	range 0x2000 0x1000000 if X86_32
2122	range 0x200000 0x1000000 if X86_64
2123	help
2124	  This value puts the alignment restrictions on physical address
2125	  where kernel is loaded and run from. Kernel is compiled for an
2126	  address which meets above alignment restriction.
2127
2128	  If bootloader loads the kernel at a non-aligned address and
2129	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2130	  address aligned to above value and run from there.
2131
2132	  If bootloader loads the kernel at a non-aligned address and
2133	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2134	  load address and decompress itself to the address it has been
2135	  compiled for and run from there. The address for which kernel is
2136	  compiled already meets above alignment restrictions. Hence the
2137	  end result is that kernel runs from a physical address meeting
2138	  above alignment restrictions.
2139
2140	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2141	  this value must be a multiple of 0x200000.
2142
2143	  Don't change this unless you know what you are doing.
2144
2145config RANDOMIZE_MEMORY
2146	bool "Randomize the kernel memory sections"
2147	depends on X86_64
2148	depends on RANDOMIZE_BASE
2149	default RANDOMIZE_BASE
2150	help
2151	  Randomizes the base virtual address of kernel memory sections
2152	  (physical memory mapping, vmalloc & vmemmap). This security feature
2153	  makes exploits relying on predictable memory locations less reliable.
2154
2155	  The order of allocations remains unchanged. Entropy is generated in
2156	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2157	  configuration have in average 30,000 different possible virtual
2158	  addresses for each memory section.
2159
2160	  If unsure, say Y.
2161
2162config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2163	hex "Physical memory mapping padding" if EXPERT
2164	depends on RANDOMIZE_MEMORY
2165	default "0xa" if MEMORY_HOTPLUG
2166	default "0x0"
2167	range 0x1 0x40 if MEMORY_HOTPLUG
2168	range 0x0 0x40
2169	help
2170	  Define the padding in terabytes added to the existing physical
2171	  memory size during kernel memory randomization. It is useful
2172	  for memory hotplug support but reduces the entropy available for
2173	  address randomization.
2174
2175	  If unsure, leave at the default value.
2176
2177config ADDRESS_MASKING
2178	bool "Linear Address Masking support"
2179	depends on X86_64
2180	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2181	help
2182	  Linear Address Masking (LAM) modifies the checking that is applied
2183	  to 64-bit linear addresses, allowing software to use of the
2184	  untranslated address bits for metadata.
2185
2186	  The capability can be used for efficient address sanitizers (ASAN)
2187	  implementation and for optimizations in JITs.
2188
2189config HOTPLUG_CPU
2190	def_bool y
2191	depends on SMP
2192
2193config COMPAT_VDSO
2194	def_bool n
2195	prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)"
2196	depends on COMPAT_32
2197	help
2198	  Certain buggy versions of glibc will crash if they are
2199	  presented with a 32-bit vDSO that is not mapped at the address
2200	  indicated in its segment table.
2201
2202	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2203	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2204	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2205	  the only released version with the bug, but OpenSUSE 9
2206	  contains a buggy "glibc 2.3.2".
2207
2208	  The symptom of the bug is that everything crashes on startup, saying:
2209	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2210
2211	  Saying Y here changes the default value of the vdso32 boot
2212	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2213	  This works around the glibc bug but hurts performance.
2214
2215	  If unsure, say N: if you are compiling your own kernel, you
2216	  are unlikely to be using a buggy version of glibc.
2217
2218choice
2219	prompt "vsyscall table for legacy applications"
2220	depends on X86_64
2221	default LEGACY_VSYSCALL_XONLY
2222	help
2223	  Legacy user code that does not know how to find the vDSO expects
2224	  to be able to issue three syscalls by calling fixed addresses in
2225	  kernel space. Since this location is not randomized with ASLR,
2226	  it can be used to assist security vulnerability exploitation.
2227
2228	  This setting can be changed at boot time via the kernel command
2229	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2230	  is deprecated and can only be enabled using the kernel command
2231	  line.
2232
2233	  On a system with recent enough glibc (2.14 or newer) and no
2234	  static binaries, you can say None without a performance penalty
2235	  to improve security.
2236
2237	  If unsure, select "Emulate execution only".
2238
2239	config LEGACY_VSYSCALL_XONLY
2240		bool "Emulate execution only"
2241		help
2242		  The kernel traps and emulates calls into the fixed vsyscall
2243		  address mapping and does not allow reads.  This
2244		  configuration is recommended when userspace might use the
2245		  legacy vsyscall area but support for legacy binary
2246		  instrumentation of legacy code is not needed.  It mitigates
2247		  certain uses of the vsyscall area as an ASLR-bypassing
2248		  buffer.
2249
2250	config LEGACY_VSYSCALL_NONE
2251		bool "None"
2252		help
2253		  There will be no vsyscall mapping at all. This will
2254		  eliminate any risk of ASLR bypass due to the vsyscall
2255		  fixed address mapping. Attempts to use the vsyscalls
2256		  will be reported to dmesg, so that either old or
2257		  malicious userspace programs can be identified.
2258
2259endchoice
2260
2261config CMDLINE_BOOL
2262	bool "Built-in kernel command line"
2263	help
2264	  Allow for specifying boot arguments to the kernel at
2265	  build time.  On some systems (e.g. embedded ones), it is
2266	  necessary or convenient to provide some or all of the
2267	  kernel boot arguments with the kernel itself (that is,
2268	  to not rely on the boot loader to provide them.)
2269
2270	  To compile command line arguments into the kernel,
2271	  set this option to 'Y', then fill in the
2272	  boot arguments in CONFIG_CMDLINE.
2273
2274	  Systems with fully functional boot loaders (i.e. non-embedded)
2275	  should leave this option set to 'N'.
2276
2277config CMDLINE
2278	string "Built-in kernel command string"
2279	depends on CMDLINE_BOOL
2280	default ""
2281	help
2282	  Enter arguments here that should be compiled into the kernel
2283	  image and used at boot time.  If the boot loader provides a
2284	  command line at boot time, it is appended to this string to
2285	  form the full kernel command line, when the system boots.
2286
2287	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2288	  change this behavior.
2289
2290	  In most cases, the command line (whether built-in or provided
2291	  by the boot loader) should specify the device for the root
2292	  file system.
2293
2294config CMDLINE_OVERRIDE
2295	bool "Built-in command line overrides boot loader arguments"
2296	depends on CMDLINE_BOOL && CMDLINE != ""
2297	help
2298	  Set this option to 'Y' to have the kernel ignore the boot loader
2299	  command line, and use ONLY the built-in command line.
2300
2301	  This is used to work around broken boot loaders.  This should
2302	  be set to 'N' under normal conditions.
2303
2304config MODIFY_LDT_SYSCALL
2305	bool "Enable the LDT (local descriptor table)" if EXPERT
2306	default y
2307	help
2308	  Linux can allow user programs to install a per-process x86
2309	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2310	  call.  This is required to run 16-bit or segmented code such as
2311	  DOSEMU or some Wine programs.  It is also used by some very old
2312	  threading libraries.
2313
2314	  Enabling this feature adds a small amount of overhead to
2315	  context switches and increases the low-level kernel attack
2316	  surface.  Disabling it removes the modify_ldt(2) system call.
2317
2318	  Saying 'N' here may make sense for embedded or server kernels.
2319
2320config STRICT_SIGALTSTACK_SIZE
2321	bool "Enforce strict size checking for sigaltstack"
2322	depends on DYNAMIC_SIGFRAME
2323	help
2324	  For historical reasons MINSIGSTKSZ is a constant which became
2325	  already too small with AVX512 support. Add a mechanism to
2326	  enforce strict checking of the sigaltstack size against the
2327	  real size of the FPU frame. This option enables the check
2328	  by default. It can also be controlled via the kernel command
2329	  line option 'strict_sas_size' independent of this config
2330	  switch. Enabling it might break existing applications which
2331	  allocate a too small sigaltstack but 'work' because they
2332	  never get a signal delivered.
2333
2334	  Say 'N' unless you want to really enforce this check.
2335
2336config CFI_AUTO_DEFAULT
2337	bool "Attempt to use FineIBT by default at boot time"
2338	depends on FINEIBT
2339	depends on !RUST || RUSTC_VERSION >= 108800
2340	default y
2341	help
2342	  Attempt to use FineIBT by default at boot time. If enabled,
2343	  this is the same as booting with "cfi=auto". If disabled,
2344	  this is the same as booting with "cfi=kcfi".
2345
2346source "kernel/livepatch/Kconfig"
2347
2348config X86_BUS_LOCK_DETECT
2349	bool "Split Lock Detect and Bus Lock Detect support"
2350	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2351	default y
2352	help
2353	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2354	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2355
2356endmenu
2357
2358config CC_HAS_NAMED_AS
2359	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2360	depends on CC_IS_GCC
2361
2362#
2363# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2364# are incompatible with named address spaces with GCC < 13.3
2365# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2366#
2367
2368config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2369	def_bool y
2370	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2371	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2372
2373config USE_X86_SEG_SUPPORT
2374	def_bool CC_HAS_NAMED_AS
2375	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2376
2377config CC_HAS_SLS
2378	def_bool $(cc-option,-mharden-sls=all)
2379
2380config CC_HAS_RETURN_THUNK
2381	def_bool $(cc-option,-mfunction-return=thunk-extern)
2382
2383config CC_HAS_ENTRY_PADDING
2384	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2385
2386config CC_HAS_KCFI_ARITY
2387	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2388	depends on CC_IS_CLANG && !RUST
2389
2390config FUNCTION_PADDING_CFI
2391	int
2392	default 59 if FUNCTION_ALIGNMENT_64B
2393	default 27 if FUNCTION_ALIGNMENT_32B
2394	default 11 if FUNCTION_ALIGNMENT_16B
2395	default  3 if FUNCTION_ALIGNMENT_8B
2396	default  0
2397
2398# Basically: FUNCTION_ALIGNMENT - 5*CFI
2399# except Kconfig can't do arithmetic :/
2400config FUNCTION_PADDING_BYTES
2401	int
2402	default FUNCTION_PADDING_CFI if CFI
2403	default FUNCTION_ALIGNMENT
2404
2405config CALL_PADDING
2406	def_bool n
2407	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2408	select FUNCTION_ALIGNMENT_16B
2409
2410config FINEIBT
2411	def_bool y
2412	depends on X86_KERNEL_IBT && CFI && MITIGATION_RETPOLINE
2413	select CALL_PADDING
2414
2415config FINEIBT_BHI
2416	def_bool y
2417	depends on FINEIBT && CC_HAS_KCFI_ARITY
2418
2419config HAVE_CALL_THUNKS
2420	def_bool y
2421	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2422
2423config CALL_THUNKS
2424	def_bool n
2425	select CALL_PADDING
2426
2427config PREFIX_SYMBOLS
2428	def_bool y
2429	depends on CALL_PADDING && !CFI
2430
2431menuconfig CPU_MITIGATIONS
2432	bool "Mitigations for CPU vulnerabilities"
2433	default y
2434	help
2435	  Say Y here to enable options which enable mitigations for hardware
2436	  vulnerabilities (usually related to speculative execution).
2437	  Mitigations can be disabled or restricted to SMT systems at runtime
2438	  via the "mitigations" kernel parameter.
2439
2440	  If you say N, all mitigations will be disabled.  This CANNOT be
2441	  overridden at runtime.
2442
2443	  Say 'Y', unless you really know what you are doing.
2444
2445if CPU_MITIGATIONS
2446
2447config MITIGATION_PAGE_TABLE_ISOLATION
2448	bool "Remove the kernel mapping in user mode"
2449	default y
2450	depends on (X86_64 || X86_PAE)
2451	help
2452	  This feature reduces the number of hardware side channels by
2453	  ensuring that the majority of kernel addresses are not mapped
2454	  into userspace.
2455
2456	  See Documentation/arch/x86/pti.rst for more details.
2457
2458config MITIGATION_RETPOLINE
2459	bool "Avoid speculative indirect branches in kernel"
2460	select OBJTOOL if HAVE_OBJTOOL
2461	default y
2462	help
2463	  Compile kernel with the retpoline compiler options to guard against
2464	  kernel-to-user data leaks by avoiding speculative indirect
2465	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2466	  support for full protection. The kernel may run slower.
2467
2468config MITIGATION_RETHUNK
2469	bool "Enable return-thunks"
2470	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2471	select OBJTOOL if HAVE_OBJTOOL
2472	default y if X86_64
2473	help
2474	  Compile the kernel with the return-thunks compiler option to guard
2475	  against kernel-to-user data leaks by avoiding return speculation.
2476	  Requires a compiler with -mfunction-return=thunk-extern
2477	  support for full protection. The kernel may run slower.
2478
2479config MITIGATION_UNRET_ENTRY
2480	bool "Enable UNRET on kernel entry"
2481	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2482	default y
2483	help
2484	  Compile the kernel with support for the retbleed=unret mitigation.
2485
2486config MITIGATION_CALL_DEPTH_TRACKING
2487	bool "Mitigate RSB underflow with call depth tracking"
2488	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2489	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2490	select CALL_THUNKS
2491	default y
2492	help
2493	  Compile the kernel with call depth tracking to mitigate the Intel
2494	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2495	  by default and needs to be enabled on the kernel command line via the
2496	  retbleed=stuff option. For non-affected systems the overhead of this
2497	  option is marginal as the call depth tracking is using run-time
2498	  generated call thunks in a compiler generated padding area and call
2499	  patching. This increases text size by ~5%. For non affected systems
2500	  this space is unused. On affected SKL systems this results in a
2501	  significant performance gain over the IBRS mitigation.
2502
2503config CALL_THUNKS_DEBUG
2504	bool "Enable call thunks and call depth tracking debugging"
2505	depends on MITIGATION_CALL_DEPTH_TRACKING
2506	select FUNCTION_ALIGNMENT_32B
2507	default n
2508	help
2509	  Enable call/ret counters for imbalance detection and build in
2510	  a noisy dmesg about callthunks generation and call patching for
2511	  trouble shooting. The debug prints need to be enabled on the
2512	  kernel command line with 'debug-callthunks'.
2513	  Only enable this when you are debugging call thunks as this
2514	  creates a noticeable runtime overhead. If unsure say N.
2515
2516config MITIGATION_IBPB_ENTRY
2517	bool "Enable IBPB on kernel entry"
2518	depends on CPU_SUP_AMD && X86_64
2519	default y
2520	help
2521	  Compile the kernel with support for the retbleed=ibpb and
2522	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2523
2524config MITIGATION_IBRS_ENTRY
2525	bool "Enable IBRS on kernel entry"
2526	depends on CPU_SUP_INTEL && X86_64
2527	default y
2528	help
2529	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2530	  This mitigates both spectre_v2 and retbleed at great cost to
2531	  performance.
2532
2533config MITIGATION_SRSO
2534	bool "Mitigate speculative RAS overflow on AMD"
2535	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2536	default y
2537	help
2538	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2539
2540config MITIGATION_SLS
2541	bool "Mitigate Straight-Line-Speculation"
2542	depends on CC_HAS_SLS && X86_64
2543	select OBJTOOL if HAVE_OBJTOOL
2544	default n
2545	help
2546	  Compile the kernel with straight-line-speculation options to guard
2547	  against straight line speculation. The kernel image might be slightly
2548	  larger.
2549
2550config MITIGATION_GDS
2551	bool "Mitigate Gather Data Sampling"
2552	depends on CPU_SUP_INTEL
2553	default y
2554	help
2555	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2556	  vulnerability which allows unprivileged speculative access to data
2557	  which was previously stored in vector registers. The attacker uses gather
2558	  instructions to infer the stale vector register data.
2559
2560config MITIGATION_RFDS
2561	bool "RFDS Mitigation"
2562	depends on CPU_SUP_INTEL
2563	default y
2564	help
2565	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2566	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2567	  allows unprivileged speculative access to stale data previously
2568	  stored in floating point, vector and integer registers.
2569	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2570
2571config MITIGATION_SPECTRE_BHI
2572	bool "Mitigate Spectre-BHB (Branch History Injection)"
2573	depends on CPU_SUP_INTEL
2574	default y
2575	help
2576	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2577	  where the branch history buffer is poisoned to speculatively steer
2578	  indirect branches.
2579	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2580
2581config MITIGATION_MDS
2582	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2583	depends on CPU_SUP_INTEL
2584	default y
2585	help
2586	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2587	  a hardware vulnerability which allows unprivileged speculative access
2588	  to data which is available in various CPU internal buffers.
2589	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2590
2591config MITIGATION_TAA
2592	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2593	depends on CPU_SUP_INTEL
2594	default y
2595	help
2596	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2597	  vulnerability that allows unprivileged speculative access to data
2598	  which is available in various CPU internal buffers by using
2599	  asynchronous aborts within an Intel TSX transactional region.
2600	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2601
2602config MITIGATION_MMIO_STALE_DATA
2603	bool "Mitigate MMIO Stale Data hardware bug"
2604	depends on CPU_SUP_INTEL
2605	default y
2606	help
2607	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2608	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2609	  vulnerabilities that can expose data. The vulnerabilities require the
2610	  attacker to have access to MMIO.
2611	  See also
2612	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2613
2614config MITIGATION_L1TF
2615	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2616	depends on CPU_SUP_INTEL
2617	default y
2618	help
2619	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2620	  hardware vulnerability which allows unprivileged speculative access to data
2621	  available in the Level 1 Data Cache.
2622	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2623
2624config MITIGATION_RETBLEED
2625	bool "Mitigate RETBleed hardware bug"
2626	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2627	default y
2628	help
2629	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2630	  with Return Instructions) vulnerability.  RETBleed is a speculative
2631	  execution attack which takes advantage of microarchitectural behavior
2632	  in many modern microprocessors, similar to Spectre v2. An
2633	  unprivileged attacker can use these flaws to bypass conventional
2634	  memory security restrictions to gain read access to privileged memory
2635	  that would otherwise be inaccessible.
2636
2637config MITIGATION_SPECTRE_V1
2638	bool "Mitigate SPECTRE V1 hardware bug"
2639	default y
2640	help
2641	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2642	  class of side channel attacks that takes advantage of speculative
2643	  execution that bypasses conditional branch instructions used for
2644	  memory access bounds check.
2645	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2646
2647config MITIGATION_SPECTRE_V2
2648	bool "Mitigate SPECTRE V2 hardware bug"
2649	default y
2650	help
2651	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2652	  V2 is a class of side channel attacks that takes advantage of
2653	  indirect branch predictors inside the processor. In Spectre variant 2
2654	  attacks, the attacker can steer speculative indirect branches in the
2655	  victim to gadget code by poisoning the branch target buffer of a CPU
2656	  used for predicting indirect branch addresses.
2657	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2658
2659config MITIGATION_SRBDS
2660	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2661	depends on CPU_SUP_INTEL
2662	default y
2663	help
2664	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2665	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2666	  Sampling (MDS) techniques to infer values returned from special
2667	  register accesses. An unprivileged user can extract values returned
2668	  from RDRAND and RDSEED executed on another core or sibling thread
2669	  using MDS techniques.
2670	  See also
2671	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2672
2673config MITIGATION_SSB
2674	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2675	default y
2676	help
2677	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2678	  hardware security vulnerability and its exploitation takes advantage
2679	  of speculative execution in a similar way to the Meltdown and Spectre
2680	  security vulnerabilities.
2681
2682config MITIGATION_ITS
2683	bool "Enable Indirect Target Selection mitigation"
2684	depends on CPU_SUP_INTEL && X86_64
2685	depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK
2686	select EXECMEM
2687	default y
2688	help
2689	  Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in
2690	  BPU on some Intel CPUs that may allow Spectre V2 style attacks. If
2691	  disabled, mitigation cannot be enabled via cmdline.
2692	  See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst>
2693
2694config MITIGATION_TSA
2695	bool "Mitigate Transient Scheduler Attacks"
2696	depends on CPU_SUP_AMD
2697	default y
2698	help
2699	  Enable mitigation for Transient Scheduler Attacks. TSA is a hardware
2700	  security vulnerability on AMD CPUs which can lead to forwarding of
2701	  invalid info to subsequent instructions and thus can affect their
2702	  timing and thereby cause a leakage.
2703
2704config MITIGATION_VMSCAPE
2705	bool "Mitigate VMSCAPE"
2706	depends on KVM
2707	default y
2708	help
2709	  Enable mitigation for VMSCAPE attacks. VMSCAPE is a hardware security
2710	  vulnerability on Intel and AMD CPUs that may allow a guest to do
2711	  Spectre v2 style attacks on userspace hypervisor.
2712endif
2713
2714config ARCH_HAS_ADD_PAGES
2715	def_bool y
2716	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2717
2718menu "Power management and ACPI options"
2719
2720config ARCH_HIBERNATION_HEADER
2721	def_bool y
2722	depends on HIBERNATION
2723
2724source "kernel/power/Kconfig"
2725
2726source "drivers/acpi/Kconfig"
2727
2728config X86_APM_BOOT
2729	def_bool y
2730	depends on APM
2731
2732menuconfig APM
2733	tristate "APM (Advanced Power Management) BIOS support"
2734	depends on X86_32 && PM_SLEEP
2735	help
2736	  APM is a BIOS specification for saving power using several different
2737	  techniques. This is mostly useful for battery powered laptops with
2738	  APM compliant BIOSes. If you say Y here, the system time will be
2739	  reset after a RESUME operation, the /proc/apm device will provide
2740	  battery status information, and user-space programs will receive
2741	  notification of APM "events" (e.g. battery status change).
2742
2743	  If you select "Y" here, you can disable actual use of the APM
2744	  BIOS by passing the "apm=off" option to the kernel at boot time.
2745
2746	  Note that the APM support is almost completely disabled for
2747	  machines with more than one CPU.
2748
2749	  In order to use APM, you will need supporting software. For location
2750	  and more information, read <file:Documentation/power/apm-acpi.rst>
2751	  and the Battery Powered Linux mini-HOWTO, available from
2752	  <http://www.tldp.org/docs.html#howto>.
2753
2754	  This driver does not spin down disk drives (see the hdparm(8)
2755	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2756	  VESA-compliant "green" monitors.
2757
2758	  This driver does not support the TI 4000M TravelMate and the ACER
2759	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2760	  desktop machines also don't have compliant BIOSes, and this driver
2761	  may cause those machines to panic during the boot phase.
2762
2763	  Generally, if you don't have a battery in your machine, there isn't
2764	  much point in using this driver and you should say N. If you get
2765	  random kernel OOPSes or reboots that don't seem to be related to
2766	  anything, try disabling/enabling this option (or disabling/enabling
2767	  APM in your BIOS).
2768
2769	  Some other things you should try when experiencing seemingly random,
2770	  "weird" problems:
2771
2772	  1) make sure that you have enough swap space and that it is
2773	  enabled.
2774	  2) pass the "idle=poll" option to the kernel
2775	  3) switch on floating point emulation in the kernel and pass
2776	  the "no387" option to the kernel
2777	  4) pass the "floppy=nodma" option to the kernel
2778	  5) pass the "mem=4M" option to the kernel (thereby disabling
2779	  all but the first 4 MB of RAM)
2780	  6) make sure that the CPU is not over clocked.
2781	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2782	  8) disable the cache from your BIOS settings
2783	  9) install a fan for the video card or exchange video RAM
2784	  10) install a better fan for the CPU
2785	  11) exchange RAM chips
2786	  12) exchange the motherboard.
2787
2788	  To compile this driver as a module, choose M here: the
2789	  module will be called apm.
2790
2791if APM
2792
2793config APM_IGNORE_USER_SUSPEND
2794	bool "Ignore USER SUSPEND"
2795	help
2796	  This option will ignore USER SUSPEND requests. On machines with a
2797	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2798	  series notebooks, it is necessary to say Y because of a BIOS bug.
2799
2800config APM_DO_ENABLE
2801	bool "Enable PM at boot time"
2802	help
2803	  Enable APM features at boot time. From page 36 of the APM BIOS
2804	  specification: "When disabled, the APM BIOS does not automatically
2805	  power manage devices, enter the Standby State, enter the Suspend
2806	  State, or take power saving steps in response to CPU Idle calls."
2807	  This driver will make CPU Idle calls when Linux is idle (unless this
2808	  feature is turned off -- see "Do CPU IDLE calls", below). This
2809	  should always save battery power, but more complicated APM features
2810	  will be dependent on your BIOS implementation. You may need to turn
2811	  this option off if your computer hangs at boot time when using APM
2812	  support, or if it beeps continuously instead of suspending. Turn
2813	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2814	  T400CDT. This is off by default since most machines do fine without
2815	  this feature.
2816
2817config APM_CPU_IDLE
2818	depends on CPU_IDLE
2819	bool "Make CPU Idle calls when idle"
2820	help
2821	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2822	  On some machines, this can activate improved power savings, such as
2823	  a slowed CPU clock rate, when the machine is idle. These idle calls
2824	  are made after the idle loop has run for some length of time (e.g.,
2825	  333 mS). On some machines, this will cause a hang at boot time or
2826	  whenever the CPU becomes idle. (On machines with more than one CPU,
2827	  this option does nothing.)
2828
2829config APM_DISPLAY_BLANK
2830	bool "Enable console blanking using APM"
2831	help
2832	  Enable console blanking using the APM. Some laptops can use this to
2833	  turn off the LCD backlight when the screen blanker of the Linux
2834	  virtual console blanks the screen. Note that this is only used by
2835	  the virtual console screen blanker, and won't turn off the backlight
2836	  when using the X Window system. This also doesn't have anything to
2837	  do with your VESA-compliant power-saving monitor. Further, this
2838	  option doesn't work for all laptops -- it might not turn off your
2839	  backlight at all, or it might print a lot of errors to the console,
2840	  especially if you are using gpm.
2841
2842config APM_ALLOW_INTS
2843	bool "Allow interrupts during APM BIOS calls"
2844	help
2845	  Normally we disable external interrupts while we are making calls to
2846	  the APM BIOS as a measure to lessen the effects of a badly behaving
2847	  BIOS implementation.  The BIOS should reenable interrupts if it
2848	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2849	  many of the newer IBM Thinkpads.  If you experience hangs when you
2850	  suspend, try setting this to Y.  Otherwise, say N.
2851
2852endif # APM
2853
2854source "drivers/cpufreq/Kconfig"
2855
2856source "drivers/cpuidle/Kconfig"
2857
2858source "drivers/idle/Kconfig"
2859
2860endmenu
2861
2862menu "Bus options (PCI etc.)"
2863
2864choice
2865	prompt "PCI access mode"
2866	depends on X86_32 && PCI
2867	default PCI_GOANY
2868	help
2869	  On PCI systems, the BIOS can be used to detect the PCI devices and
2870	  determine their configuration. However, some old PCI motherboards
2871	  have BIOS bugs and may crash if this is done. Also, some embedded
2872	  PCI-based systems don't have any BIOS at all. Linux can also try to
2873	  detect the PCI hardware directly without using the BIOS.
2874
2875	  With this option, you can specify how Linux should detect the
2876	  PCI devices. If you choose "BIOS", the BIOS will be used,
2877	  if you choose "Direct", the BIOS won't be used, and if you
2878	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2879	  If you choose "Any", the kernel will try MMCONFIG, then the
2880	  direct access method and falls back to the BIOS if that doesn't
2881	  work. If unsure, go with the default, which is "Any".
2882
2883config PCI_GOBIOS
2884	bool "BIOS"
2885
2886config PCI_GOMMCONFIG
2887	bool "MMConfig"
2888
2889config PCI_GODIRECT
2890	bool "Direct"
2891
2892config PCI_GOOLPC
2893	bool "OLPC XO-1"
2894	depends on OLPC
2895
2896config PCI_GOANY
2897	bool "Any"
2898
2899endchoice
2900
2901config PCI_BIOS
2902	def_bool y
2903	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2904
2905# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2906config PCI_DIRECT
2907	def_bool y
2908	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2909
2910config PCI_MMCONFIG
2911	bool "Support mmconfig PCI config space access" if X86_64
2912	default y
2913	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2914	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2915	help
2916	  Add support for accessing the PCI configuration space as a memory
2917	  mapped area. It is the recommended method if the system supports
2918	  this (it must have PCI Express and ACPI for it to be available).
2919
2920	  In the unlikely case that enabling this configuration option causes
2921	  problems, the mechanism can be switched off with the 'pci=nommconf'
2922	  command line parameter.
2923
2924	  Say N only if you are sure that your platform does not support this
2925	  access method or you have problems caused by it.
2926
2927	  Say Y otherwise.
2928
2929config PCI_OLPC
2930	def_bool y
2931	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2932
2933config PCI_XEN
2934	def_bool y
2935	depends on PCI && XEN
2936
2937config MMCONF_FAM10H
2938	def_bool y
2939	depends on X86_64 && PCI_MMCONFIG && ACPI
2940
2941config PCI_CNB20LE_QUIRK
2942	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2943	depends on X86_32 && PCI
2944	help
2945	  Read the PCI windows out of the CNB20LE host bridge. This allows
2946	  PCI hotplug to work on systems with the CNB20LE chipset which do
2947	  not have ACPI.
2948
2949	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2950	  most probably only for Pentium III.
2951
2952	  To find out if you have such a chipset, search for a PCI device with
2953	  1166:0009 PCI IDs, for example by executing
2954		lspci -nn | grep '1166:0009'
2955	  The code is inactive if there is none.
2956
2957	  There's no public spec for this chipset, and this functionality
2958	  is known to be incomplete.
2959
2960	  You should say N unless you know you need this.
2961
2962config ISA_BUS
2963	bool "ISA bus support on modern systems" if EXPERT
2964	help
2965	  Expose ISA bus device drivers and options available for selection and
2966	  configuration. Enable this option if your target machine has an ISA
2967	  bus. ISA is an older system, displaced by PCI and newer bus
2968	  architectures -- if your target machine is modern, it probably does
2969	  not have an ISA bus.
2970
2971	  If unsure, say N.
2972
2973# x86_64 have no ISA slots, but can have ISA-style DMA.
2974config ISA_DMA_API
2975	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2976	default y
2977	help
2978	  Enables ISA-style DMA support for devices requiring such controllers.
2979	  If unsure, say Y.
2980
2981if X86_32
2982
2983config ISA
2984	bool "ISA support"
2985	help
2986	  Find out whether you have ISA slots on your motherboard.  ISA is the
2987	  name of a bus system, i.e. the way the CPU talks to the other stuff
2988	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2989	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2990	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2991
2992config SCx200
2993	tristate "NatSemi SCx200 support"
2994	help
2995	  This provides basic support for National Semiconductor's
2996	  (now AMD's) Geode processors.  The driver probes for the
2997	  PCI-IDs of several on-chip devices, so its a good dependency
2998	  for other scx200_* drivers.
2999
3000	  If compiled as a module, the driver is named scx200.
3001
3002config SCx200HR_TIMER
3003	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
3004	depends on SCx200
3005	default y
3006	help
3007	  This driver provides a clocksource built upon the on-chip
3008	  27MHz high-resolution timer.  Its also a workaround for
3009	  NSC Geode SC-1100's buggy TSC, which loses time when the
3010	  processor goes idle (as is done by the scheduler).  The
3011	  other workaround is idle=poll boot option.
3012
3013config OLPC
3014	bool "One Laptop Per Child support"
3015	depends on !X86_PAE
3016	select GPIOLIB
3017	select OF
3018	select OF_PROMTREE
3019	select IRQ_DOMAIN
3020	select OLPC_EC
3021	help
3022	  Add support for detecting the unique features of the OLPC
3023	  XO hardware.
3024
3025config OLPC_XO1_PM
3026	bool "OLPC XO-1 Power Management"
3027	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3028	help
3029	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3030
3031config OLPC_XO1_RTC
3032	bool "OLPC XO-1 Real Time Clock"
3033	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3034	help
3035	  Add support for the XO-1 real time clock, which can be used as a
3036	  programmable wakeup source.
3037
3038config OLPC_XO1_SCI
3039	bool "OLPC XO-1 SCI extras"
3040	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3041	depends on INPUT=y
3042	select POWER_SUPPLY
3043	help
3044	  Add support for SCI-based features of the OLPC XO-1 laptop:
3045	   - EC-driven system wakeups
3046	   - Power button
3047	   - Ebook switch
3048	   - Lid switch
3049	   - AC adapter status updates
3050	   - Battery status updates
3051
3052config OLPC_XO15_SCI
3053	bool "OLPC XO-1.5 SCI extras"
3054	depends on OLPC && ACPI
3055	select POWER_SUPPLY
3056	help
3057	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3058	   - EC-driven system wakeups
3059	   - AC adapter status updates
3060	   - Battery status updates
3061
3062config GEODE_COMMON
3063	bool
3064
3065config ALIX
3066	bool "PCEngines ALIX System Support (LED setup)"
3067	select GPIOLIB
3068	select GEODE_COMMON
3069	help
3070	  This option enables system support for the PCEngines ALIX.
3071	  At present this just sets up LEDs for GPIO control on
3072	  ALIX2/3/6 boards.  However, other system specific setup should
3073	  get added here.
3074
3075	  Note: You must still enable the drivers for GPIO and LED support
3076	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3077
3078	  Note: You have to set alix.force=1 for boards with Award BIOS.
3079
3080config NET5501
3081	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3082	select GPIOLIB
3083	select GEODE_COMMON
3084	help
3085	  This option enables system support for the Soekris Engineering net5501.
3086
3087config GEOS
3088	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3089	select GPIOLIB
3090	select GEODE_COMMON
3091	depends on DMI
3092	help
3093	  This option enables system support for the Traverse Technologies GEOS.
3094
3095config TS5500
3096	bool "Technologic Systems TS-5500 platform support"
3097	depends on MELAN
3098	select CHECK_SIGNATURE
3099	select NEW_LEDS
3100	select LEDS_CLASS
3101	help
3102	  This option enables system support for the Technologic Systems TS-5500.
3103
3104endif # X86_32
3105
3106config AMD_NB
3107	def_bool y
3108	depends on AMD_NODE
3109
3110config AMD_NODE
3111	def_bool y
3112	depends on CPU_SUP_AMD && PCI
3113
3114endmenu
3115
3116menu "Binary Emulations"
3117
3118config IA32_EMULATION
3119	bool "IA32 Emulation"
3120	depends on X86_64
3121	select ARCH_WANT_OLD_COMPAT_IPC
3122	select BINFMT_ELF
3123	select COMPAT_OLD_SIGACTION
3124	help
3125	  Include code to run legacy 32-bit programs under a
3126	  64-bit kernel. You should likely turn this on, unless you're
3127	  100% sure that you don't have any 32-bit programs left.
3128
3129config IA32_EMULATION_DEFAULT_DISABLED
3130	bool "IA32 emulation disabled by default"
3131	default n
3132	depends on IA32_EMULATION
3133	help
3134	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3135	  processes and access to 32-bit syscalls. If unsure, leave it to its
3136	  default value.
3137
3138config X86_X32_ABI
3139	bool "x32 ABI for 64-bit mode"
3140	depends on X86_64
3141	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3142	# compressed debug sections to x86_x32 properly:
3143	# https://github.com/ClangBuiltLinux/linux/issues/514
3144	# https://github.com/ClangBuiltLinux/linux/issues/1141
3145	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3146	help
3147	  Include code to run binaries for the x32 native 32-bit ABI
3148	  for 64-bit processors.  An x32 process gets access to the
3149	  full 64-bit register file and wide data path while leaving
3150	  pointers at 32 bits for smaller memory footprint.
3151
3152config COMPAT_32
3153	def_bool y
3154	depends on IA32_EMULATION || X86_32
3155	select HAVE_UID16
3156	select OLD_SIGSUSPEND3
3157
3158config COMPAT
3159	def_bool y
3160	depends on IA32_EMULATION || X86_X32_ABI
3161
3162config COMPAT_FOR_U64_ALIGNMENT
3163	def_bool y
3164	depends on COMPAT
3165
3166endmenu
3167
3168config HAVE_ATOMIC_IOMAP
3169	def_bool y
3170	depends on X86_32
3171
3172source "arch/x86/kvm/Kconfig"
3173
3174source "arch/x86/Kconfig.cpufeatures"
3175
3176source "arch/x86/Kconfig.assembler"
3177