xref: /linux/arch/x86/Kconfig (revision e9635f2a73604ad9cb33d480b489a03bdd03329f)
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_CLOCKSOURCE_READ_INLINE	if X86_64
145	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
146	select ARCH_WANTS_NO_INSTR
147	select ARCH_WANT_GENERAL_HUGETLB
148	select ARCH_WANT_HUGE_PMD_SHARE		if X86_64
149	select ARCH_WANT_LD_ORPHAN_WARN
150	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
151	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
152	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
153	select ARCH_WANTS_THP_SWAP		if X86_64
154	select ARCH_HAS_PARANOID_L1D_FLUSH
155	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
156	select BUILDTIME_TABLE_SORT
157	select CLKEVT_I8253
158	select CLOCKSOURCE_WATCHDOG
159	# Word-size accesses may read uninitialized data past the trailing \0
160	# in strings and cause false KMSAN reports.
161	select DCACHE_WORD_ACCESS		if !KMSAN
162	select DYNAMIC_SIGFRAME
163	select EDAC_ATOMIC_SCRUB
164	select EDAC_SUPPORT
165	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
166	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
167	select GENERIC_CLOCKEVENTS_COUPLED_INLINE	if X86_64
168	select GENERIC_CLOCKEVENTS_MIN_ADJUST
169	select GENERIC_CMOS_UPDATE
170	select GENERIC_CPU_AUTOPROBE
171	select GENERIC_CPU_DEVICES
172	select GENERIC_CPU_VULNERABILITIES
173	select GENERIC_EARLY_IOREMAP
174	select GENERIC_ENTRY
175	select GENERIC_IOMAP
176	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
177	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
178	select GENERIC_IRQ_MIGRATION		if SMP
179	select GENERIC_IRQ_PROBE
180	select GENERIC_IRQ_RESERVATION_MODE
181	select GENERIC_IRQ_SHOW
182	select GENERIC_PENDING_IRQ		if SMP
183	select GENERIC_SMP_IDLE_THREAD
184	select GENERIC_TIME_VSYSCALL
185	select GENERIC_GETTIMEOFDAY
186	select GENERIC_VDSO_OVERFLOW_PROTECT
187	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
188	select HARDIRQS_SW_RESEND
189	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
190	select HAS_IOPORT
191	select HAVE_ACPI_APEI			if ACPI
192	select HAVE_ACPI_APEI_NMI		if ACPI
193	select HAVE_ALIGNED_STRUCT_PAGE
194	select HAVE_ARCH_AUDITSYSCALL
195	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
196	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
197	select HAVE_ARCH_JUMP_LABEL
198	select HAVE_ARCH_JUMP_LABEL_RELATIVE
199	select HAVE_ARCH_KASAN			if X86_64
200	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
201	select HAVE_ARCH_KFENCE
202	select HAVE_ARCH_KMSAN			if X86_64
203	select HAVE_ARCH_KGDB
204	select HAVE_ARCH_KSTACK_ERASE
205	select HAVE_ARCH_MMAP_RND_BITS		if MMU
206	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
207	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
208	select HAVE_ARCH_PREL32_RELOCATIONS
209	select HAVE_ARCH_SECCOMP_FILTER
210	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
211	select HAVE_ARCH_TRACEHOOK
212	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
213	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
214	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
215	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
216	select HAVE_ARCH_VMAP_STACK		if X86_64
217	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
218	select HAVE_ARCH_WITHIN_STACK_FRAMES
219	select HAVE_ASM_MODVERSIONS
220	select HAVE_CMPXCHG_DOUBLE
221	select HAVE_CMPXCHG_LOCAL
222	select HAVE_CONTEXT_TRACKING_USER		if X86_64
223	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
224	select HAVE_C_RECORDMCOUNT
225	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
226	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
227	select HAVE_BUILDTIME_MCOUNT_SORT
228	select HAVE_DEBUG_KMEMLEAK
229	select HAVE_DMA_CONTIGUOUS
230	select HAVE_DYNAMIC_FTRACE
231	select HAVE_DYNAMIC_FTRACE_WITH_REGS
232	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
233	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
234	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
235	select HAVE_DYNAMIC_FTRACE_WITH_JMP	if X86_64
236	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
237	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
238	select HAVE_EBPF_JIT
239	select HAVE_EFFICIENT_UNALIGNED_ACCESS
240	select HAVE_EISA			if X86_32
241	select HAVE_EXIT_THREAD
242	select HAVE_GENERIC_TIF_BITS
243	select HAVE_GUP_FAST
244	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
245	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
246	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
247	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
248	select HAVE_FUNCTION_TRACER
249	select HAVE_GCC_PLUGINS
250	select HAVE_HW_BREAKPOINT
251	select HAVE_IOREMAP_PROT
252	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
253	select HAVE_IRQ_TIME_ACCOUNTING
254	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
255	select HAVE_KERNEL_BZIP2
256	select HAVE_KERNEL_GZIP
257	select HAVE_KERNEL_LZ4
258	select HAVE_KERNEL_LZMA
259	select HAVE_KERNEL_LZO
260	select HAVE_KERNEL_XZ
261	select HAVE_KERNEL_ZSTD
262	select HAVE_KPROBES
263	select HAVE_KPROBES_ON_FTRACE
264	select HAVE_FUNCTION_ERROR_INJECTION
265	select HAVE_KRETPROBES
266	select HAVE_RETHOOK
267	select HAVE_KLP_BUILD			if X86_64
268	select HAVE_LIVEPATCH			if X86_64
269	select HAVE_MIXED_BREAKPOINTS_REGS
270	select HAVE_MOD_ARCH_SPECIFIC
271	select HAVE_MOVE_PMD
272	select HAVE_MOVE_PUD
273	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
274	select HAVE_NMI
275	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
276	select HAVE_OBJTOOL			if X86_64
277	select HAVE_OPTPROBES
278	select HAVE_PAGE_SIZE_4KB
279	select HAVE_PCSPKR_PLATFORM
280	select HAVE_PERF_EVENTS
281	select HAVE_PERF_EVENTS_NMI
282	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
283	select HAVE_PCI
284	select HAVE_PERF_REGS
285	select HAVE_PERF_USER_STACK_DUMP
286	select ASYNC_KERNEL_PGTABLE_FREE	if IOMMU_SVA
287	select MMU_GATHER_RCU_TABLE_FREE
288	select MMU_GATHER_MERGE_VMAS
289	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
290	select HAVE_REGS_AND_STACK_ACCESS_API
291	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
292	select HAVE_FUNCTION_ARG_ACCESS_API
293	select HAVE_SETUP_PER_CPU_AREA
294	select HAVE_SOFTIRQ_ON_OWN_STACK
295	select HAVE_STACKPROTECTOR
296	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
297	select HAVE_STATIC_CALL
298	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
299	select HAVE_PREEMPT_DYNAMIC_CALL
300	select HAVE_RSEQ
301	select HAVE_RUST			if X86_64
302	select HAVE_SYSCALL_TRACEPOINTS
303	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
304	select HAVE_UNSTABLE_SCHED_CLOCK
305	select HAVE_UNWIND_USER_FP		if X86_64
306	select HAVE_USER_RETURN_NOTIFIER
307	select HAVE_GENERIC_VDSO
308	select VDSO_GETRANDOM			if X86_64
309	select HOTPLUG_PARALLEL			if SMP && X86_64
310	select HOTPLUG_SMT			if SMP
311	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
312	select IRQ_FORCED_THREADING
313	select LOCK_MM_AND_FIND_VMA
314	select NEED_PER_CPU_EMBED_FIRST_CHUNK
315	select NEED_PER_CPU_PAGE_FIRST_CHUNK
316	select NEED_SG_DMA_LENGTH
317	select NUMA_MEMBLKS			if NUMA
318	select PCI_DOMAINS			if PCI
319	select PCI_LOCKLESS_CONFIG		if PCI
320	select PERF_EVENTS
321	select RTC_LIB
322	select RTC_MC146818_LIB
323	select SPARSE_IRQ
324	select SYSCTL_EXCEPTION_TRACE
325	select THREAD_INFO_IN_TASK
326	select TRACE_IRQFLAGS_SUPPORT
327	select TRACE_IRQFLAGS_NMI_SUPPORT
328	select USER_STACKTRACE_SUPPORT
329	select HAVE_ARCH_KCSAN			if X86_64
330	select PROC_PID_ARCH_STATUS		if PROC_FS
331	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
332	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
333	select FUNCTION_ALIGNMENT_4B
334	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
335	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
336	select ARCH_SUPPORTS_SCHED_SMT		if SMP
337	select SCHED_SMT			if SMP
338	select ARCH_SUPPORTS_SCHED_CLUSTER	if SMP
339	select ARCH_SUPPORTS_SCHED_MC		if SMP
340	select HAVE_SINGLE_FTRACE_DIRECT_OPS	if X86_64 && DYNAMIC_FTRACE_WITH_DIRECT_CALLS
341
342config INSTRUCTION_DECODER
343	def_bool y
344	depends on KPROBES || PERF_EVENTS || UPROBES
345
346config OUTPUT_FORMAT
347	string
348	default "elf32-i386" if X86_32
349	default "elf64-x86-64" if X86_64
350
351config LOCKDEP_SUPPORT
352	def_bool y
353
354config STACKTRACE_SUPPORT
355	def_bool y
356
357config MMU
358	def_bool y
359
360config ARCH_MMAP_RND_BITS_MIN
361	default 28 if 64BIT
362	default 8
363
364config ARCH_MMAP_RND_BITS_MAX
365	default 32 if 64BIT
366	default 16
367
368config ARCH_MMAP_RND_COMPAT_BITS_MIN
369	default 8
370
371config ARCH_MMAP_RND_COMPAT_BITS_MAX
372	default 16
373
374config SBUS
375	bool
376
377config GENERIC_ISA_DMA
378	def_bool y
379	depends on ISA_DMA_API
380
381config GENERIC_CSUM
382	bool
383	default y if KMSAN || KASAN
384
385config GENERIC_BUG
386	def_bool y
387	depends on BUG
388	select GENERIC_BUG_RELATIVE_POINTERS
389
390config GENERIC_BUG_RELATIVE_POINTERS
391	bool
392
393config ARCH_MAY_HAVE_PC_FDC
394	def_bool y
395	depends on ISA_DMA_API
396
397config GENERIC_CALIBRATE_DELAY
398	def_bool y
399
400config ARCH_HAS_CPU_RELAX
401	def_bool y
402
403config ARCH_HIBERNATION_POSSIBLE
404	def_bool y
405
406config ARCH_SUSPEND_POSSIBLE
407	def_bool y
408
409config AUDIT_ARCH
410	def_bool y if X86_64
411
412config KASAN_SHADOW_OFFSET
413	hex
414	depends on KASAN
415	default 0xdffffc0000000000
416
417config HAVE_INTEL_TXT
418	def_bool y
419	depends on INTEL_IOMMU && ACPI
420
421config ARCH_SUPPORTS_UPROBES
422	def_bool y
423
424config FIX_EARLYCON_MEM
425	def_bool y
426
427config DYNAMIC_PHYSICAL_MASK
428	bool
429
430config PGTABLE_LEVELS
431	int
432	default 5 if X86_64
433	default 3 if X86_PAE
434	default 2
435
436menu "Processor type and features"
437
438config SMP
439	bool "Symmetric multi-processing support"
440	help
441	  This enables support for systems with more than one CPU. If you have
442	  a system with only one CPU, say N. If you have a system with more
443	  than one CPU, say Y.
444
445	  If you say N here, the kernel will run on uni- and multiprocessor
446	  machines, but will use only one CPU of a multiprocessor machine. If
447	  you say Y here, the kernel will run on many, but not all,
448	  uniprocessor machines. On a uniprocessor machine, the kernel
449	  will run faster if you say N here.
450
451	  People using multiprocessor machines who say Y here should also say
452	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
453	  Management" code will be disabled if you say Y here.
454
455	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
456	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
457	  <http://www.tldp.org/docs.html#howto>.
458
459	  If you don't know what to do here, say N.
460
461config X86_X2APIC
462	bool "x2APIC interrupt controller architecture support"
463	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
464	default y
465	help
466	  x2APIC is an interrupt controller architecture, a component of which
467	  (the local APIC) is present in the CPU. It allows faster access to
468	  the local APIC and supports a larger number of CPUs in the system
469	  than the predecessors.
470
471	  x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs
472	  in 2019, but it can be disabled by the BIOS. It is also frequently
473	  emulated in virtual machines, even when the host CPU does not support
474	  it. Support in the CPU can be checked by executing
475		grep x2apic /proc/cpuinfo
476
477	  If this configuration option is disabled, the kernel will boot with
478	  very reduced functionality and performance on some platforms that
479	  have x2APIC enabled. On the other hand, on hardware that does not
480	  support x2APIC, a kernel with this option enabled will just fallback
481	  to older APIC implementations.
482
483	  If in doubt, say Y.
484
485config AMD_SECURE_AVIC
486	bool "AMD Secure AVIC"
487	depends on AMD_MEM_ENCRYPT && X86_X2APIC
488	help
489	  Enable this to get AMD Secure AVIC support on guests that have this feature.
490
491	  AMD Secure AVIC provides hardware acceleration for performance sensitive
492	  APIC accesses and support for managing guest owned APIC state for SEV-SNP
493	  guests. Secure AVIC does not support xAPIC mode. It has functional
494	  dependency on x2apic being enabled in the guest.
495
496	  If you don't know what to do here, say N.
497
498config X86_POSTED_MSI
499	bool "Enable MSI and MSI-x delivery by posted interrupts"
500	depends on X86_64 && IRQ_REMAP
501	help
502	  This enables MSIs that are under interrupt remapping to be delivered as
503	  posted interrupts to the host kernel. Interrupt throughput can
504	  potentially be improved by coalescing CPU notifications during high
505	  frequency bursts.
506
507	  If you don't know what to do here, say N.
508
509config X86_MPPARSE
510	bool "Enable MPS table" if ACPI
511	default y
512	depends on X86_LOCAL_APIC
513	help
514	  For old smp systems that do not have proper acpi support. Newer systems
515	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
516
517config X86_CPU_RESCTRL
518	bool "x86 CPU resource control support"
519	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
520	depends on MISC_FILESYSTEMS
521	select ARCH_HAS_CPU_RESCTRL
522	select RESCTRL_FS
523	select RESCTRL_FS_PSEUDO_LOCK
524	help
525	  Enable x86 CPU resource control support.
526
527	  Provide support for the allocation and monitoring of system resources
528	  usage by the CPU.
529
530	  Intel calls this Intel Resource Director Technology
531	  (Intel(R) RDT). More information about RDT can be found in the
532	  Intel x86 Architecture Software Developer Manual.
533
534	  AMD calls this AMD Platform Quality of Service (AMD QoS).
535	  More information about AMD QoS can be found in the AMD64 Technology
536	  Platform Quality of Service Extensions manual.
537
538	  Say N if unsure.
539
540config X86_CPU_RESCTRL_INTEL_AET
541	bool "Intel Application Energy Telemetry"
542	depends on X86_64 && X86_CPU_RESCTRL && CPU_SUP_INTEL && INTEL_PMT_TELEMETRY=y && INTEL_TPMI=y
543	help
544	  Enable per-RMID telemetry events in resctrl.
545
546	  Intel feature that collects per-RMID execution data
547	  about energy consumption, measure of frequency independent
548	  activity and other performance metrics. Data is aggregated
549	  per package.
550
551	  Say N if unsure.
552
553config X86_FRED
554	bool "Flexible Return and Event Delivery"
555	depends on X86_64
556	help
557	  When enabled, use Flexible Return and Event Delivery
558	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
559	  ring transitions and exception/interrupt handling if the
560	  system supports it.
561
562config X86_EXTENDED_PLATFORM
563	bool "Support for extended (non-PC) x86 platforms"
564	default y
565	help
566	  If you disable this option then the kernel will only support
567	  standard PC platforms. (which covers the vast majority of
568	  systems out there.)
569
570	  If you enable this option then you'll be able to select support
571	  for the following non-PC x86 platforms, depending on the value of
572	  CONFIG_64BIT.
573
574	  32-bit platforms (CONFIG_64BIT=n):
575		Goldfish (mostly Android emulator)
576		Intel CE media processor (CE4100) SoC
577		Intel Quark
578		RDC R-321x SoC
579
580	  64-bit platforms (CONFIG_64BIT=y):
581		Numascale NumaChip
582		ScaleMP vSMP
583		SGI Ultraviolet
584		Merrifield/Moorefield MID devices
585		Goldfish (mostly Android emulator)
586
587	  If you have one of these systems, or if you want to build a
588	  generic distribution kernel, say Y here - otherwise say N.
589
590# This is an alphabetically sorted list of 64 bit extended platforms
591# Please maintain the alphabetic order if and when there are additions
592config X86_NUMACHIP
593	bool "Numascale NumaChip"
594	depends on X86_64
595	depends on X86_EXTENDED_PLATFORM
596	depends on NUMA
597	depends on SMP
598	depends on X86_X2APIC
599	depends on PCI_MMCONFIG
600	help
601	  Adds support for Numascale NumaChip large-SMP systems. Needed to
602	  enable more than ~168 cores.
603	  If you don't have one of these, you should say N here.
604
605config X86_VSMP
606	bool "ScaleMP vSMP"
607	select HYPERVISOR_GUEST
608	select PARAVIRT
609	depends on X86_64 && PCI
610	depends on X86_EXTENDED_PLATFORM
611	depends on SMP
612	help
613	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
614	  supposed to run on these EM64T-based machines.  Only choose this option
615	  if you have one of these machines.
616
617config X86_UV
618	bool "SGI Ultraviolet"
619	depends on X86_64
620	depends on X86_EXTENDED_PLATFORM
621	depends on NUMA
622	depends on EFI
623	depends on KEXEC_CORE
624	depends on X86_X2APIC
625	depends on PCI
626	help
627	  This option is needed in order to support SGI Ultraviolet systems.
628	  If you don't have one of these, you should say N here.
629
630config X86_INTEL_MID
631	bool "Intel Z34xx/Z35xx MID platform support"
632	depends on X86_EXTENDED_PLATFORM
633	depends on X86_PLATFORM_DEVICES
634	depends on PCI
635	depends on X86_64 || (EXPERT && PCI_GOANY)
636	depends on X86_IO_APIC
637	select I2C
638	select DW_APB_TIMER
639	select INTEL_SCU_PCI
640	help
641	  Select to build a kernel capable of supporting 64-bit Intel MID
642	  (Mobile Internet Device) platform systems which do not have
643	  the PCI legacy interfaces.
644
645	  The only supported devices are the 22nm Merrified (Z34xx)
646	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
647	  a small number of Android devices such as the Asus Zenfone 2,
648	  Asus FonePad 8 and Dell Venue 7.
649
650	  If you are building for a PC class system or non-MID tablet
651	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
652
653	  Intel MID platforms are based on an Intel processor and chipset which
654	  consume less power than most of the x86 derivatives.
655
656config X86_GOLDFISH
657	bool "Goldfish (Virtual Platform)"
658	depends on X86_EXTENDED_PLATFORM
659	help
660	  Enable support for the Goldfish virtual platform used primarily
661	  for Android development. Unless you are building for the Android
662	  Goldfish emulator say N here.
663
664# Following is an alphabetically sorted list of 32 bit extended platforms
665# Please maintain the alphabetic order if and when there are additions
666
667config X86_INTEL_CE
668	bool "CE4100 TV platform"
669	depends on PCI
670	depends on PCI_GODIRECT
671	depends on X86_IO_APIC
672	depends on X86_32
673	depends on X86_EXTENDED_PLATFORM
674	select X86_REBOOTFIXUPS
675	select OF
676	select OF_EARLY_FLATTREE
677	help
678	  Select for the Intel CE media processor (CE4100) SOC.
679	  This option compiles in support for the CE4100 SOC for settop
680	  boxes and media devices.
681
682config X86_INTEL_QUARK
683	bool "Intel Quark platform support"
684	depends on X86_32
685	depends on X86_EXTENDED_PLATFORM
686	depends on X86_PLATFORM_DEVICES
687	depends on X86_TSC
688	depends on PCI
689	depends on PCI_GOANY
690	depends on X86_IO_APIC
691	select IOSF_MBI
692	select INTEL_IMR
693	select COMMON_CLK
694	help
695	  Select to include support for Quark X1000 SoC.
696	  Say Y here if you have a Quark based system such as the Arduino
697	  compatible Intel Galileo.
698
699config X86_RDC321X
700	bool "RDC R-321x SoC"
701	depends on X86_32
702	depends on X86_EXTENDED_PLATFORM
703	select M486
704	select X86_REBOOTFIXUPS
705	help
706	  This option is needed for RDC R-321x system-on-chip, also known
707	  as R-8610-(G).
708	  If you don't have one of these chips, you should say N here.
709
710config X86_INTEL_LPSS
711	bool "Intel Low Power Subsystem Support"
712	depends on X86 && ACPI && PCI
713	select COMMON_CLK
714	select PINCTRL
715	select IOSF_MBI
716	help
717	  Select to build support for Intel Low Power Subsystem such as
718	  found on Intel Lynxpoint PCH. Selecting this option enables
719	  things like clock tree (common clock framework) and pincontrol
720	  which are needed by the LPSS peripheral drivers.
721
722config X86_AMD_PLATFORM_DEVICE
723	bool "AMD ACPI2Platform devices support"
724	depends on ACPI
725	select COMMON_CLK
726	select PINCTRL
727	help
728	  Select to interpret AMD specific ACPI device to platform device
729	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
730	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
731	  implemented under PINCTRL subsystem.
732
733config IOSF_MBI
734	tristate "Intel SoC IOSF Sideband support for SoC platforms"
735	depends on PCI
736	help
737	  This option enables sideband register access support for Intel SoC
738	  platforms. On these platforms the IOSF sideband is used in lieu of
739	  MSR's for some register accesses, mostly but not limited to thermal
740	  and power. Drivers may query the availability of this device to
741	  determine if they need the sideband in order to work on these
742	  platforms. The sideband is available on the following SoC products.
743	  This list is not meant to be exclusive.
744	   - BayTrail
745	   - Braswell
746	   - Quark
747
748	  You should say Y if you are running a kernel on one of these SoC's.
749
750config IOSF_MBI_DEBUG
751	bool "Enable IOSF sideband access through debugfs"
752	depends on IOSF_MBI && DEBUG_FS
753	help
754	  Select this option to expose the IOSF sideband access registers (MCR,
755	  MDR, MCRX) through debugfs to write and read register information from
756	  different units on the SoC. This is most useful for obtaining device
757	  state information for debug and analysis. As this is a general access
758	  mechanism, users of this option would have specific knowledge of the
759	  device they want to access.
760
761	  If you don't require the option or are in doubt, say N.
762
763config X86_SUPPORTS_MEMORY_FAILURE
764	def_bool y
765	# MCE code calls memory_failure():
766	depends on X86_MCE
767	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
768	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
769	depends on X86_64 || !SPARSEMEM
770	select ARCH_SUPPORTS_MEMORY_FAILURE
771
772config X86_32_IRIS
773	tristate "Eurobraille/Iris poweroff module"
774	depends on X86_32
775	help
776	  The Iris machines from EuroBraille do not have APM or ACPI support
777	  to shut themselves down properly.  A special I/O sequence is
778	  needed to do so, which is what this module does at
779	  kernel shutdown.
780
781	  This is only for Iris machines from EuroBraille.
782
783	  If unused, say N.
784
785config SCHED_OMIT_FRAME_POINTER
786	def_bool y
787	prompt "Single-depth WCHAN output"
788	depends on X86
789	help
790	  Calculate simpler /proc/<PID>/wchan values. If this option
791	  is disabled then wchan values will recurse back to the
792	  caller function. This provides more accurate wchan values,
793	  at the expense of slightly more scheduling overhead.
794
795	  If in doubt, say "Y".
796
797menuconfig HYPERVISOR_GUEST
798	bool "Linux guest support"
799	help
800	  Say Y here to enable options for running Linux under various hyper-
801	  visors. This option enables basic hypervisor detection and platform
802	  setup.
803
804	  If you say N, all options in this submenu will be skipped and
805	  disabled, and Linux guest support won't be built in.
806
807if HYPERVISOR_GUEST
808
809config PARAVIRT
810	bool "Enable paravirtualization code"
811	depends on HAVE_STATIC_CALL
812	select HAVE_PV_STEAL_CLOCK_GEN
813	help
814	  This changes the kernel so it can modify itself when it is run
815	  under a hypervisor, potentially improving performance significantly
816	  over full virtualization.  However, when run without a hypervisor
817	  the kernel is theoretically slower and slightly larger.
818
819config PARAVIRT_XXL
820	bool
821	depends on X86_64
822	select ARCH_HAS_LAZY_MMU_MODE
823
824config PARAVIRT_SPINLOCKS
825	bool "Paravirtualization layer for spinlocks"
826	depends on PARAVIRT && SMP
827	help
828	  Paravirtualized spinlocks allow a pvops backend to replace the
829	  spinlock implementation with something virtualization-friendly
830	  (for example, block the virtual CPU rather than spinning).
831
832	  It has a minimal impact on native kernels and gives a nice performance
833	  benefit on paravirtualized KVM / Xen kernels.
834
835	  If you are unsure how to answer this question, answer Y.
836
837config X86_HV_CALLBACK_VECTOR
838	def_bool n
839
840source "arch/x86/xen/Kconfig"
841
842config KVM_GUEST
843	bool "KVM Guest support (including kvmclock)"
844	depends on PARAVIRT
845	select PARAVIRT_CLOCK
846	select ARCH_CPUIDLE_HALTPOLL
847	select X86_HV_CALLBACK_VECTOR
848	default y
849	help
850	  This option enables various optimizations for running under the KVM
851	  hypervisor. It includes a paravirtualized clock, so that instead
852	  of relying on a PIT (or probably other) emulation by the
853	  underlying device model, the host provides the guest with
854	  timing infrastructure such as time of day, and system time
855
856config ARCH_CPUIDLE_HALTPOLL
857	def_bool n
858	prompt "Disable host haltpoll when loading haltpoll driver"
859	help
860	  If virtualized under KVM, disable host haltpoll.
861
862config PVH
863	bool "Support for running PVH guests"
864	help
865	  This option enables the PVH entry point for guest virtual machines
866	  as specified in the x86/HVM direct boot ABI.
867
868config PARAVIRT_TIME_ACCOUNTING
869	bool "Paravirtual steal time accounting"
870	depends on PARAVIRT
871	help
872	  Select this option to enable fine granularity task steal time
873	  accounting. Time spent executing other tasks in parallel with
874	  the current vCPU is discounted from the vCPU power. To account for
875	  that, there can be a small performance impact.
876
877	  If in doubt, say N here.
878
879config PARAVIRT_CLOCK
880	bool
881
882config JAILHOUSE_GUEST
883	bool "Jailhouse non-root cell support"
884	depends on X86_64 && PCI
885	select X86_PM_TIMER
886	help
887	  This option allows to run Linux as guest in a Jailhouse non-root
888	  cell. You can leave this option disabled if you only want to start
889	  Jailhouse and run Linux afterwards in the root cell.
890
891config ACRN_GUEST
892	bool "ACRN Guest support"
893	depends on X86_64
894	select X86_HV_CALLBACK_VECTOR
895	help
896	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
897	  a flexible, lightweight reference open-source hypervisor, built with
898	  real-time and safety-criticality in mind. It is built for embedded
899	  IOT with small footprint and real-time features. More details can be
900	  found in https://projectacrn.org/.
901
902config BHYVE_GUEST
903	bool "Bhyve (BSD Hypervisor) Guest support"
904	depends on X86_64
905	help
906	  This option allows to run Linux to recognise when it is running as a
907	  guest in the Bhyve hypervisor, and to support more than 255 vCPUs when
908	  when doing so. More details about Bhyve can be found at https://bhyve.org
909	  and https://wiki.freebsd.org/bhyve/.
910
911config INTEL_TDX_GUEST
912	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
913	depends on X86_64 && CPU_SUP_INTEL
914	depends on X86_X2APIC
915	depends on EFI_STUB
916	depends on PARAVIRT
917	select ARCH_HAS_CC_PLATFORM
918	select X86_MEM_ENCRYPT
919	select X86_MCE
920	select UNACCEPTED_MEMORY
921	help
922	  Support running as a guest under Intel TDX.  Without this support,
923	  the guest kernel can not boot or run under TDX.
924	  TDX includes memory encryption and integrity capabilities
925	  which protect the confidentiality and integrity of guest
926	  memory contents and CPU state. TDX guests are protected from
927	  some attacks from the VMM.
928
929endif # HYPERVISOR_GUEST
930
931source "arch/x86/Kconfig.cpu"
932
933config HPET_TIMER
934	def_bool X86_64
935	prompt "HPET Timer Support" if X86_32
936	help
937	  Use the IA-PC HPET (High Precision Event Timer) to manage
938	  time in preference to the PIT and RTC, if a HPET is
939	  present.
940	  HPET is the next generation timer replacing legacy 8254s.
941	  The HPET provides a stable time base on SMP
942	  systems, unlike the TSC, but it is more expensive to access,
943	  as it is off-chip.  The interface used is documented
944	  in the HPET spec, revision 1.
945
946	  You can safely choose Y here.  However, HPET will only be
947	  activated if the platform and the BIOS support this feature.
948	  Otherwise the 8254 will be used for timing services.
949
950	  Choose N to continue using the legacy 8254 timer.
951
952config HPET_EMULATE_RTC
953	def_bool y
954	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
955
956# Mark as expert because too many people got it wrong.
957# The code disables itself when not needed.
958config DMI
959	default y
960	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
961	bool "Enable DMI scanning" if EXPERT
962	help
963	  Enabled scanning of DMI to identify machine quirks. Say Y
964	  here unless you have verified that your setup is not
965	  affected by entries in the DMI blacklist. Required by PNP
966	  BIOS code.
967
968config GART_IOMMU
969	bool "Old AMD GART IOMMU support"
970	select IOMMU_HELPER
971	select SWIOTLB
972	depends on X86_64 && PCI && AMD_NB
973	help
974	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
975	  GART based hardware IOMMUs.
976
977	  The GART supports full DMA access for devices with 32-bit access
978	  limitations, on systems with more than 3 GB. This is usually needed
979	  for USB, sound, many IDE/SATA chipsets and some other devices.
980
981	  Newer systems typically have a modern AMD IOMMU, supported via
982	  the CONFIG_AMD_IOMMU=y config option.
983
984	  In normal configurations this driver is only active when needed:
985	  there's more than 3 GB of memory and the system contains a
986	  32-bit limited device.
987
988	  If unsure, say Y.
989
990config BOOT_VESA_SUPPORT
991	bool
992	help
993	  If true, at least one selected framebuffer driver can take advantage
994	  of VESA video modes set at an early boot stage via the vga= parameter.
995
996config MAXSMP
997	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
998	depends on X86_64 && SMP && DEBUG_KERNEL
999	select CPUMASK_OFFSTACK
1000	help
1001	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
1002	  If unsure, say N.
1003
1004#
1005# The maximum number of CPUs supported:
1006#
1007# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
1008# and which can be configured interactively in the
1009# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
1010#
1011# The ranges are different on 32-bit and 64-bit kernels, depending on
1012# hardware capabilities and scalability features of the kernel.
1013#
1014# ( If MAXSMP is enabled we just use the highest possible value and disable
1015#   interactive configuration. )
1016#
1017
1018config NR_CPUS_RANGE_BEGIN
1019	int
1020	default NR_CPUS_RANGE_END if MAXSMP
1021	default    1 if !SMP
1022	default    2
1023
1024config NR_CPUS_RANGE_END
1025	int
1026	depends on X86_32
1027	default    8 if  SMP
1028	default    1 if !SMP
1029
1030config NR_CPUS_RANGE_END
1031	int
1032	depends on X86_64
1033	default 8192 if  SMP && CPUMASK_OFFSTACK
1034	default  512 if  SMP && !CPUMASK_OFFSTACK
1035	default    1 if !SMP
1036
1037config NR_CPUS_DEFAULT
1038	int
1039	depends on X86_32
1040	default    8 if  SMP
1041	default    1 if !SMP
1042
1043config NR_CPUS_DEFAULT
1044	int
1045	depends on X86_64
1046	default 8192 if  MAXSMP
1047	default   64 if  SMP
1048	default    1 if !SMP
1049
1050config NR_CPUS
1051	int "Maximum number of CPUs" if SMP && !MAXSMP
1052	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1053	default NR_CPUS_DEFAULT
1054	help
1055	  This allows you to specify the maximum number of CPUs which this
1056	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1057	  supported value is 8192, otherwise the maximum value is 512.  The
1058	  minimum value which makes sense is 2.
1059
1060	  This is purely to save memory: each supported CPU adds about 8KB
1061	  to the kernel image.
1062
1063config SCHED_MC_PRIO
1064	bool "CPU core priorities scheduler support"
1065	depends on SCHED_MC
1066	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1067	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1068	select CPU_FREQ
1069	default y
1070	help
1071	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1072	  core ordering determined at manufacturing time, which allows
1073	  certain cores to reach higher turbo frequencies (when running
1074	  single threaded workloads) than others.
1075
1076	  Enabling this kernel feature teaches the scheduler about
1077	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1078	  scheduler's CPU selection logic accordingly, so that higher
1079	  overall system performance can be achieved.
1080
1081	  This feature will have no effect on CPUs without this feature.
1082
1083	  If unsure say Y here.
1084
1085config UP_LATE_INIT
1086	def_bool y
1087	depends on !SMP && X86_LOCAL_APIC
1088
1089config X86_UP_APIC
1090	bool "Local APIC support on uniprocessors" if !PCI_MSI
1091	default PCI_MSI
1092	depends on X86_32 && !SMP
1093	help
1094	  A local APIC (Advanced Programmable Interrupt Controller) is an
1095	  integrated interrupt controller in the CPU. If you have a single-CPU
1096	  system which has a processor with a local APIC, you can say Y here to
1097	  enable and use it. If you say Y here even though your machine doesn't
1098	  have a local APIC, then the kernel will still run with no slowdown at
1099	  all. The local APIC supports CPU-generated self-interrupts (timer,
1100	  performance counters), and the NMI watchdog which detects hard
1101	  lockups.
1102
1103config X86_UP_IOAPIC
1104	bool "IO-APIC support on uniprocessors"
1105	depends on X86_UP_APIC
1106	help
1107	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1108	  SMP-capable replacement for PC-style interrupt controllers. Most
1109	  SMP systems and many recent uniprocessor systems have one.
1110
1111	  If you have a single-CPU system with an IO-APIC, you can say Y here
1112	  to use it. If you say Y here even though your machine doesn't have
1113	  an IO-APIC, then the kernel will still run with no slowdown at all.
1114
1115config X86_LOCAL_APIC
1116	def_bool y
1117	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1118	select IRQ_DOMAIN_HIERARCHY
1119
1120config ACPI_MADT_WAKEUP
1121	def_bool y
1122	depends on X86_64
1123	depends on ACPI
1124	depends on SMP
1125	depends on X86_LOCAL_APIC
1126
1127config X86_IO_APIC
1128	def_bool y
1129	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1130
1131config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1132	bool "Reroute for broken boot IRQs"
1133	depends on X86_IO_APIC
1134	help
1135	  This option enables a workaround that fixes a source of
1136	  spurious interrupts. This is recommended when threaded
1137	  interrupt handling is used on systems where the generation of
1138	  superfluous "boot interrupts" cannot be disabled.
1139
1140	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1141	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1142	  kernel does during interrupt handling). On chipsets where this
1143	  boot IRQ generation cannot be disabled, this workaround keeps
1144	  the original IRQ line masked so that only the equivalent "boot
1145	  IRQ" is delivered to the CPUs. The workaround also tells the
1146	  kernel to set up the IRQ handler on the boot IRQ line. In this
1147	  way only one interrupt is delivered to the kernel. Otherwise
1148	  the spurious second interrupt may cause the kernel to bring
1149	  down (vital) interrupt lines.
1150
1151	  Only affects "broken" chipsets. Interrupt sharing may be
1152	  increased on these systems.
1153
1154config X86_MCE
1155	bool "Machine Check / overheating reporting"
1156	select GENERIC_ALLOCATOR
1157	default y
1158	help
1159	  Machine Check support allows the processor to notify the
1160	  kernel if it detects a problem (e.g. overheating, data corruption).
1161	  The action the kernel takes depends on the severity of the problem,
1162	  ranging from warning messages to halting the machine.
1163
1164config X86_MCELOG_LEGACY
1165	bool "Support for deprecated /dev/mcelog character device"
1166	depends on X86_MCE
1167	help
1168	  Enable support for /dev/mcelog which is needed by the old mcelog
1169	  userspace logging daemon. Consider switching to the new generation
1170	  rasdaemon solution.
1171
1172config X86_MCE_INTEL
1173	def_bool y
1174	prompt "Intel MCE features"
1175	depends on X86_MCE && X86_LOCAL_APIC
1176	help
1177	  Additional support for intel specific MCE features such as
1178	  the thermal monitor.
1179
1180config X86_MCE_AMD
1181	def_bool y
1182	prompt "AMD MCE features"
1183	depends on X86_MCE && X86_LOCAL_APIC
1184	help
1185	  Additional support for AMD specific MCE features such as
1186	  the DRAM Error Threshold.
1187
1188config X86_ANCIENT_MCE
1189	bool "Support for old Pentium 5 / WinChip machine checks"
1190	depends on X86_32 && X86_MCE
1191	help
1192	  Include support for machine check handling on old Pentium 5 or WinChip
1193	  systems. These typically need to be enabled explicitly on the command
1194	  line.
1195
1196config X86_MCE_THRESHOLD
1197	depends on X86_MCE_AMD || X86_MCE_INTEL
1198	def_bool y
1199
1200config X86_MCE_INJECT
1201	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1202	tristate "Machine check injector support"
1203	help
1204	  Provide support for injecting machine checks for testing purposes.
1205	  If you don't know what a machine check is and you don't do kernel
1206	  QA it is safe to say n.
1207
1208source "arch/x86/events/Kconfig"
1209
1210config X86_LEGACY_VM86
1211	bool "Legacy VM86 support"
1212	depends on X86_32
1213	help
1214	  This option allows user programs to put the CPU into V8086
1215	  mode, which is an 80286-era approximation of 16-bit real mode.
1216
1217	  Some very old versions of X and/or vbetool require this option
1218	  for user mode setting.  Similarly, DOSEMU will use it if
1219	  available to accelerate real mode DOS programs.  However, any
1220	  recent version of DOSEMU, X, or vbetool should be fully
1221	  functional even without kernel VM86 support, as they will all
1222	  fall back to software emulation. Nevertheless, if you are using
1223	  a 16-bit DOS program where 16-bit performance matters, vm86
1224	  mode might be faster than emulation and you might want to
1225	  enable this option.
1226
1227	  Note that any app that works on a 64-bit kernel is unlikely to
1228	  need this option, as 64-bit kernels don't, and can't, support
1229	  V8086 mode. This option is also unrelated to 16-bit protected
1230	  mode and is not needed to run most 16-bit programs under Wine.
1231
1232	  Enabling this option increases the complexity of the kernel
1233	  and slows down exception handling a tiny bit.
1234
1235	  If unsure, say N here.
1236
1237config VM86
1238	bool
1239	default X86_LEGACY_VM86
1240
1241config X86_16BIT
1242	bool "Enable support for 16-bit segments" if EXPERT
1243	default y
1244	depends on MODIFY_LDT_SYSCALL
1245	help
1246	  This option is required by programs like Wine to run 16-bit
1247	  protected mode legacy code on x86 processors.  Disabling
1248	  this option saves about 300 bytes on i386, or around 6K text
1249	  plus 16K runtime memory on x86-64,
1250
1251config X86_ESPFIX32
1252	def_bool y
1253	depends on X86_16BIT && X86_32
1254
1255config X86_ESPFIX64
1256	def_bool y
1257	depends on X86_16BIT && X86_64
1258
1259config X86_VSYSCALL_EMULATION
1260	bool "Enable vsyscall emulation" if EXPERT
1261	default y
1262	depends on X86_64
1263	help
1264	  This enables emulation of the legacy vsyscall page.  Disabling
1265	  it is roughly equivalent to booting with vsyscall=none, except
1266	  that it will also disable the helpful warning if a program
1267	  tries to use a vsyscall.  With this option set to N, offending
1268	  programs will just segfault, citing addresses of the form
1269	  0xffffffffff600?00.
1270
1271	  This option is required by many programs built before 2013, and
1272	  care should be used even with newer programs if set to N.
1273
1274	  Disabling this option saves about 7K of kernel size and
1275	  possibly 4K of additional runtime pagetable memory.
1276
1277config X86_IOPL_IOPERM
1278	bool "IOPERM and IOPL Emulation"
1279	default y
1280	help
1281	  This enables the ioperm() and iopl() syscalls which are necessary
1282	  for legacy applications.
1283
1284	  Legacy IOPL support is an overbroad mechanism which allows user
1285	  space aside of accessing all 65536 I/O ports also to disable
1286	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1287	  capabilities and permission from potentially active security
1288	  modules.
1289
1290	  The emulation restricts the functionality of the syscall to
1291	  only allowing the full range I/O port access, but prevents the
1292	  ability to disable interrupts from user space which would be
1293	  granted if the hardware IOPL mechanism would be used.
1294
1295config TOSHIBA
1296	tristate "Toshiba Laptop support"
1297	depends on X86_32
1298	help
1299	  This adds a driver to safely access the System Management Mode of
1300	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1301	  not work on models with a Phoenix BIOS. The System Management Mode
1302	  is used to set the BIOS and power saving options on Toshiba portables.
1303
1304	  For information on utilities to make use of this driver see the
1305	  Toshiba Linux utilities web site at:
1306	  <http://www.buzzard.org.uk/toshiba/>.
1307
1308	  Say Y if you intend to run this kernel on a Toshiba portable.
1309	  Say N otherwise.
1310
1311config X86_REBOOTFIXUPS
1312	bool "Enable X86 board specific fixups for reboot"
1313	depends on X86_32
1314	help
1315	  This enables chipset and/or board specific fixups to be done
1316	  in order to get reboot to work correctly. This is only needed on
1317	  some combinations of hardware and BIOS. The symptom, for which
1318	  this config is intended, is when reboot ends with a stalled/hung
1319	  system.
1320
1321	  Currently, the only fixup is for the Geode machines using
1322	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1323
1324	  Say Y if you want to enable the fixup. Currently, it's safe to
1325	  enable this option even if you don't need it.
1326	  Say N otherwise.
1327
1328config MICROCODE
1329	def_bool y
1330	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1331	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1332
1333config MICROCODE_INITRD32
1334	def_bool y
1335	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1336
1337config MICROCODE_LATE_LOADING
1338	bool "Late microcode loading (DANGEROUS)"
1339	default n
1340	depends on MICROCODE && SMP
1341	help
1342	  Loading microcode late, when the system is up and executing instructions
1343	  is a tricky business and should be avoided if possible. Just the sequence
1344	  of synchronizing all cores and SMT threads is one fragile dance which does
1345	  not guarantee that cores might not softlock after the loading. Therefore,
1346	  use this at your own risk. Late loading taints the kernel unless the
1347	  microcode header indicates that it is safe for late loading via the
1348	  minimal revision check. This minimal revision check can be enforced on
1349	  the kernel command line with "microcode=force_minrev".
1350
1351config MICROCODE_LATE_FORCE_MINREV
1352	bool "Enforce late microcode loading minimal revision check"
1353	default n
1354	depends on MICROCODE_LATE_LOADING
1355	help
1356	  To prevent that users load microcode late which modifies already
1357	  in use features, newer microcode patches have a minimum revision field
1358	  in the microcode header, which tells the kernel which minimum
1359	  revision must be active in the CPU to safely load that new microcode
1360	  late into the running system. If disabled the check will not
1361	  be enforced but the kernel will be tainted when the minimal
1362	  revision check fails.
1363
1364	  This minimal revision check can also be controlled via the
1365	  "microcode=force_minrev" parameter on the kernel command line.
1366
1367	  If unsure say Y.
1368
1369config MICROCODE_DBG
1370	bool "Enable microcode loader debugging"
1371	default n
1372	depends on MICROCODE
1373	help
1374	  Enable code which allows to debug the microcode loader. When running
1375	  in a guest the patch loading is simulated but everything else
1376	  related to patch parsing and handling is done as on baremetal with
1377	  the purpose of debugging solely the software side of things. On
1378	  baremetal, it simply dumps additional debugging information during
1379	  normal operation.
1380
1381	  You almost certainly want to say n here.
1382
1383config X86_MSR
1384	tristate "/dev/cpu/*/msr - Model-specific register support"
1385	help
1386	  This device gives privileged processes access to the x86
1387	  Model-Specific Registers (MSRs).  It is a character device with
1388	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1389	  MSR accesses are directed to a specific CPU on multi-processor
1390	  systems.
1391
1392config X86_CPUID
1393	tristate "/dev/cpu/*/cpuid - CPU information support"
1394	help
1395	  This device gives processes access to the x86 CPUID instruction to
1396	  be executed on a specific processor.  It is a character device
1397	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1398	  /dev/cpu/31/cpuid.
1399
1400config HIGHMEM4G
1401	bool "High Memory Support"
1402	depends on X86_32
1403	help
1404	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1405	  However, the address space of 32-bit x86 processors is only 4
1406	  Gigabytes large. That means that, if you have a large amount of
1407	  physical memory, not all of it can be "permanently mapped" by the
1408	  kernel. The physical memory that's not permanently mapped is called
1409	  "high memory".
1410
1411	  If you are compiling a kernel which will never run on a machine with
1412	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1413	  choice and suitable for most users). This will result in a "3GB/1GB"
1414	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1415	  space and the remaining part of the 4GB virtual memory space is used
1416	  by the kernel to permanently map as much physical memory as
1417	  possible.
1418
1419	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1420	  answer "Y" here.
1421
1422	  If unsure, say N.
1423
1424choice
1425	prompt "Memory split" if EXPERT
1426	default VMSPLIT_3G
1427	depends on X86_32
1428	help
1429	  Select the desired split between kernel and user memory.
1430
1431	  If the address range available to the kernel is less than the
1432	  physical memory installed, the remaining memory will be available
1433	  as "high memory". Accessing high memory is a little more costly
1434	  than low memory, as it needs to be mapped into the kernel first.
1435	  Note that increasing the kernel address space limits the range
1436	  available to user programs, making the address space there
1437	  tighter.  Selecting anything other than the default 3G/1G split
1438	  will also likely make your kernel incompatible with binary-only
1439	  kernel modules.
1440
1441	  If you are not absolutely sure what you are doing, leave this
1442	  option alone!
1443
1444	config VMSPLIT_3G
1445		bool "3G/1G user/kernel split"
1446	config VMSPLIT_3G_OPT
1447		depends on !X86_PAE
1448		bool "3G/1G user/kernel split (for full 1G low memory)"
1449	config VMSPLIT_2G
1450		bool "2G/2G user/kernel split"
1451	config VMSPLIT_2G_OPT
1452		depends on !X86_PAE
1453		bool "2G/2G user/kernel split (for full 2G low memory)"
1454	config VMSPLIT_1G
1455		bool "1G/3G user/kernel split"
1456endchoice
1457
1458config PAGE_OFFSET
1459	hex
1460	default 0xB0000000 if VMSPLIT_3G_OPT
1461	default 0x80000000 if VMSPLIT_2G
1462	default 0x78000000 if VMSPLIT_2G_OPT
1463	default 0x40000000 if VMSPLIT_1G
1464	default 0xC0000000
1465	depends on X86_32
1466
1467config HIGHMEM
1468	def_bool HIGHMEM4G
1469
1470config X86_PAE
1471	bool "PAE (Physical Address Extension) Support"
1472	depends on X86_32 && X86_HAVE_PAE
1473	select PHYS_ADDR_T_64BIT
1474	help
1475	  PAE is required for NX support, and furthermore enables
1476	  larger swapspace support for non-overcommit purposes. It
1477	  has the cost of more pagetable lookup overhead, and also
1478	  consumes more pagetable space per process.
1479
1480config X86_DIRECT_GBPAGES
1481	def_bool y
1482	depends on X86_64
1483	help
1484	  Certain kernel features effectively disable kernel
1485	  linear 1 GB mappings (even if the CPU otherwise
1486	  supports them), so don't confuse the user by printing
1487	  that we have them enabled.
1488
1489config X86_CPA_STATISTICS
1490	bool "Enable statistic for Change Page Attribute"
1491	depends on DEBUG_FS
1492	help
1493	  Expose statistics about the Change Page Attribute mechanism, which
1494	  helps to determine the effectiveness of preserving large and huge
1495	  page mappings when mapping protections are changed.
1496
1497config X86_MEM_ENCRYPT
1498	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1499	select DYNAMIC_PHYSICAL_MASK
1500	def_bool n
1501
1502config AMD_MEM_ENCRYPT
1503	bool "AMD Secure Memory Encryption (SME) support"
1504	depends on X86_64 && CPU_SUP_AMD
1505	depends on EFI_STUB
1506	select DMA_COHERENT_POOL
1507	select ARCH_USE_MEMREMAP_PROT
1508	select INSTRUCTION_DECODER
1509	select ARCH_HAS_CC_PLATFORM
1510	select X86_MEM_ENCRYPT
1511	select UNACCEPTED_MEMORY
1512	select CRYPTO_LIB_AESGCM
1513	help
1514	  Say yes to enable support for the encryption of system memory.
1515	  This requires an AMD processor that supports Secure Memory
1516	  Encryption (SME).
1517
1518# Common NUMA Features
1519config NUMA
1520	bool "NUMA Memory Allocation and Scheduler Support"
1521	depends on SMP
1522	depends on X86_64
1523	select USE_PERCPU_NUMA_NODE_ID
1524	select OF_NUMA if OF
1525	help
1526	  Enable NUMA (Non-Uniform Memory Access) support.
1527
1528	  The kernel will try to allocate memory used by a CPU on the
1529	  local memory controller of the CPU and add some more
1530	  NUMA awareness to the kernel.
1531
1532	  For 64-bit this is recommended if the system is Intel Core i7
1533	  (or later), AMD Opteron, or EM64T NUMA.
1534
1535	  Otherwise, you should say N.
1536
1537config AMD_NUMA
1538	def_bool y
1539	prompt "Old style AMD Opteron NUMA detection"
1540	depends on X86_64 && NUMA && PCI
1541	help
1542	  Enable AMD NUMA node topology detection.  You should say Y here if
1543	  you have a multi processor AMD system. This uses an old method to
1544	  read the NUMA configuration directly from the builtin Northbridge
1545	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1546	  which also takes priority if both are compiled in.
1547
1548config X86_64_ACPI_NUMA
1549	def_bool y
1550	prompt "ACPI NUMA detection"
1551	depends on X86_64 && NUMA && ACPI && PCI
1552	select ACPI_NUMA
1553	help
1554	  Enable ACPI SRAT based node topology detection.
1555
1556config NODES_SHIFT
1557	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1558	range 1 10
1559	default "10" if MAXSMP
1560	default "6" if X86_64
1561	default "3"
1562	depends on NUMA
1563	help
1564	  Specify the maximum number of NUMA Nodes available on the target
1565	  system.  Increases memory reserved to accommodate various tables.
1566
1567config ARCH_FLATMEM_ENABLE
1568	def_bool y
1569	depends on X86_32 && !NUMA
1570
1571config ARCH_SPARSEMEM_ENABLE
1572	def_bool y
1573	select SPARSEMEM_STATIC if X86_32
1574	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1575
1576config ARCH_SPARSEMEM_DEFAULT
1577	def_bool X86_64 || (NUMA && X86_32)
1578
1579config ARCH_SELECT_MEMORY_MODEL
1580	def_bool y
1581	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1582
1583config ARCH_MEMORY_PROBE
1584	bool "Enable sysfs memory/probe interface"
1585	depends on MEMORY_HOTPLUG
1586	help
1587	  This option enables a sysfs memory/probe interface for testing.
1588	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1589	  If you are unsure how to answer this question, answer N.
1590
1591config ARCH_PROC_KCORE_TEXT
1592	def_bool y
1593	depends on X86_64 && PROC_KCORE
1594
1595config ILLEGAL_POINTER_VALUE
1596	hex
1597	default 0 if X86_32
1598	default 0xdead000000000000 if X86_64
1599
1600config X86_PMEM_LEGACY_DEVICE
1601	bool
1602
1603config X86_PMEM_LEGACY
1604	tristate "Support non-standard NVDIMMs and ADR protected memory"
1605	depends on PHYS_ADDR_T_64BIT
1606	depends on BLK_DEV
1607	select X86_PMEM_LEGACY_DEVICE
1608	select NUMA_KEEP_MEMINFO if NUMA
1609	select LIBNVDIMM
1610	help
1611	  Treat memory marked using the non-standard e820 type of 12 as used
1612	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1613	  The kernel will offer these regions to the 'pmem' driver so
1614	  they can be used for persistent storage.
1615
1616	  Say Y if unsure.
1617
1618config X86_CHECK_BIOS_CORRUPTION
1619	bool "Check for low memory corruption"
1620	help
1621	  Periodically check for memory corruption in low memory, which
1622	  is suspected to be caused by BIOS.  Even when enabled in the
1623	  configuration, it is disabled at runtime.  Enable it by
1624	  setting "memory_corruption_check=1" on the kernel command
1625	  line.  By default it scans the low 64k of memory every 60
1626	  seconds; see the memory_corruption_check_size and
1627	  memory_corruption_check_period parameters in
1628	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1629
1630	  When enabled with the default parameters, this option has
1631	  almost no overhead, as it reserves a relatively small amount
1632	  of memory and scans it infrequently.  It both detects corruption
1633	  and prevents it from affecting the running system.
1634
1635	  It is, however, intended as a diagnostic tool; if repeatable
1636	  BIOS-originated corruption always affects the same memory,
1637	  you can use memmap= to prevent the kernel from using that
1638	  memory.
1639
1640config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1641	bool "Set the default setting of memory_corruption_check"
1642	depends on X86_CHECK_BIOS_CORRUPTION
1643	default y
1644	help
1645	  Set whether the default state of memory_corruption_check is
1646	  on or off.
1647
1648config MATH_EMULATION
1649	bool
1650	depends on MODIFY_LDT_SYSCALL
1651	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1652	help
1653	  Linux can emulate a math coprocessor (used for floating point
1654	  operations) if you don't have one. 486DX and Pentium processors have
1655	  a math coprocessor built in, 486SX and 386 do not, unless you added
1656	  a 487DX or 387, respectively. (The messages during boot time can
1657	  give you some hints here ["man dmesg"].) Everyone needs either a
1658	  coprocessor or this emulation.
1659
1660	  If you don't have a math coprocessor, you need to say Y here; if you
1661	  say Y here even though you have a coprocessor, the coprocessor will
1662	  be used nevertheless. (This behavior can be changed with the kernel
1663	  command line option "no387", which comes handy if your coprocessor
1664	  is broken. Try "man bootparam" or see the documentation of your boot
1665	  loader (lilo or loadlin) about how to pass options to the kernel at
1666	  boot time.) This means that it is a good idea to say Y here if you
1667	  intend to use this kernel on different machines.
1668
1669	  More information about the internals of the Linux math coprocessor
1670	  emulation can be found in <file:arch/x86/math-emu/README>.
1671
1672	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1673	  kernel, it won't hurt.
1674
1675config MTRR
1676	def_bool y
1677	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1678	help
1679	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1680	  the Memory Type Range Registers (MTRRs) may be used to control
1681	  processor access to memory ranges. This is most useful if you have
1682	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1683	  allows bus write transfers to be combined into a larger transfer
1684	  before bursting over the PCI/AGP bus. This can increase performance
1685	  of image write operations 2.5 times or more. Saying Y here creates a
1686	  /proc/mtrr file which may be used to manipulate your processor's
1687	  MTRRs. Typically the X server should use this.
1688
1689	  This code has a reasonably generic interface so that similar
1690	  control registers on other processors can be easily supported
1691	  as well:
1692
1693	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1694	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1695	  these, the ARRs are used to emulate the MTRRs.
1696	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1697	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1698	  write-combining. All of these processors are supported by this code
1699	  and it makes sense to say Y here if you have one of them.
1700
1701	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1702	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1703	  can lead to all sorts of problems, so it's good to say Y here.
1704
1705	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1706	  just add about 9 KB to your kernel.
1707
1708	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1709
1710config MTRR_SANITIZER
1711	def_bool y
1712	prompt "MTRR cleanup support"
1713	depends on MTRR
1714	help
1715	  Convert MTRR layout from continuous to discrete, so X drivers can
1716	  add writeback entries.
1717
1718	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1719	  The largest mtrr entry size for a continuous block can be set with
1720	  mtrr_chunk_size.
1721
1722	  If unsure, say Y.
1723
1724config MTRR_SANITIZER_ENABLE_DEFAULT
1725	int "MTRR cleanup enable value (0-1)"
1726	range 0 1
1727	default "0"
1728	depends on MTRR_SANITIZER
1729	help
1730	  Enable mtrr cleanup default value
1731
1732config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1733	int "MTRR cleanup spare reg num (0-7)"
1734	range 0 7
1735	default "1"
1736	depends on MTRR_SANITIZER
1737	help
1738	  mtrr cleanup spare entries default, it can be changed via
1739	  mtrr_spare_reg_nr=N on the kernel command line.
1740
1741config X86_PAT
1742	def_bool y
1743	prompt "x86 PAT support" if EXPERT
1744	depends on MTRR
1745	select ARCH_USES_PG_ARCH_2
1746	help
1747	  Use PAT attributes to setup page level cache control.
1748
1749	  PATs are the modern equivalents of MTRRs and are much more
1750	  flexible than MTRRs.
1751
1752	  Say N here if you see bootup problems (boot crash, boot hang,
1753	  spontaneous reboots) or a non-working video driver.
1754
1755	  If unsure, say Y.
1756
1757config X86_UMIP
1758	def_bool y
1759	prompt "User Mode Instruction Prevention" if EXPERT
1760	help
1761	  User Mode Instruction Prevention (UMIP) is a security feature in
1762	  some x86 processors. If enabled, a general protection fault is
1763	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1764	  executed in user mode. These instructions unnecessarily expose
1765	  information about the hardware state.
1766
1767	  The vast majority of applications do not use these instructions.
1768	  For the very few that do, software emulation is provided in
1769	  specific cases in protected and virtual-8086 modes. Emulated
1770	  results are dummy.
1771
1772config CC_HAS_IBT
1773	# GCC >= 9 and binutils >= 2.29
1774	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1775	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || CC_IS_CLANG) && \
1776		  $(as-instr,endbr64)
1777
1778config X86_CET
1779	def_bool n
1780	help
1781	  CET features configured (Shadow stack or IBT)
1782
1783config X86_KERNEL_IBT
1784	prompt "Indirect Branch Tracking"
1785	def_bool y
1786	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1787	select OBJTOOL
1788	select X86_CET
1789	help
1790	  Build the kernel with support for Indirect Branch Tracking, a
1791	  hardware support course-grain forward-edge Control Flow Integrity
1792	  protection. It enforces that all indirect calls must land on
1793	  an ENDBR instruction, as such, the compiler will instrument the
1794	  code with them to make this happen.
1795
1796	  In addition to building the kernel with IBT, seal all functions that
1797	  are not indirect call targets, avoiding them ever becoming one.
1798
1799	  This requires LTO like objtool runs and will slow down the build. It
1800	  does significantly reduce the number of ENDBR instructions in the
1801	  kernel image.
1802
1803config X86_INTEL_MEMORY_PROTECTION_KEYS
1804	prompt "Memory Protection Keys"
1805	def_bool y
1806	# Note: only available in 64-bit mode
1807	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1808	select ARCH_USES_HIGH_VMA_FLAGS
1809	select ARCH_HAS_PKEYS
1810	help
1811	  Memory Protection Keys provides a mechanism for enforcing
1812	  page-based protections, but without requiring modification of the
1813	  page tables when an application changes protection domains.
1814
1815	  For details, see Documentation/core-api/protection-keys.rst
1816
1817	  If unsure, say y.
1818
1819config ARCH_PKEY_BITS
1820	int
1821	default 4
1822
1823choice
1824	prompt "TSX enable mode"
1825	depends on CPU_SUP_INTEL
1826	default X86_INTEL_TSX_MODE_AUTO
1827	help
1828	  Intel's TSX (Transactional Synchronization Extensions) feature
1829	  allows to optimize locking protocols through lock elision which
1830	  can lead to a noticeable performance boost.
1831
1832	  On the other hand it has been shown that TSX can be exploited
1833	  to form side channel attacks (e.g. TAA) and chances are there
1834	  will be more of those attacks discovered in the future.
1835
1836	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1837	  might override this decision by tsx=on the command line parameter.
1838	  Even with TSX enabled, the kernel will attempt to enable the best
1839	  possible TAA mitigation setting depending on the microcode available
1840	  for the particular machine.
1841
1842	  This option allows to set the default tsx mode between tsx=on, =off
1843	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1844	  details.
1845
1846	  Say off if not sure, auto if TSX is in use but it should be used on safe
1847	  platforms or on if TSX is in use and the security aspect of tsx is not
1848	  relevant.
1849
1850config X86_INTEL_TSX_MODE_OFF
1851	bool "off"
1852	help
1853	  TSX is disabled if possible - equals to tsx=off command line parameter.
1854
1855config X86_INTEL_TSX_MODE_ON
1856	bool "on"
1857	help
1858	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1859	  line parameter.
1860
1861config X86_INTEL_TSX_MODE_AUTO
1862	bool "auto"
1863	help
1864	  TSX is enabled on TSX capable HW that is believed to be safe against
1865	  side channel attacks- equals the tsx=auto command line parameter.
1866endchoice
1867
1868config X86_SGX
1869	bool "Software Guard eXtensions (SGX)"
1870	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1871	select CRYPTO_LIB_SHA256
1872	select MMU_NOTIFIER
1873	select NUMA_KEEP_MEMINFO if NUMA
1874	select XARRAY_MULTI
1875	help
1876	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1877	  that can be used by applications to set aside private regions of code
1878	  and data, referred to as enclaves. An enclave's private memory can
1879	  only be accessed by code running within the enclave. Accesses from
1880	  outside the enclave, including other enclaves, are disallowed by
1881	  hardware.
1882
1883	  If unsure, say N.
1884
1885config X86_USER_SHADOW_STACK
1886	bool "X86 userspace shadow stack"
1887	depends on AS_WRUSS
1888	depends on X86_64
1889	select ARCH_USES_HIGH_VMA_FLAGS
1890	select ARCH_HAS_USER_SHADOW_STACK
1891	select X86_CET
1892	help
1893	  Shadow stack protection is a hardware feature that detects function
1894	  return address corruption.  This helps mitigate ROP attacks.
1895	  Applications must be enabled to use it, and old userspace does not
1896	  get protection "for free".
1897
1898	  CPUs supporting shadow stacks were first released in 2020.
1899
1900	  See Documentation/arch/x86/shstk.rst for more information.
1901
1902	  If unsure, say N.
1903
1904config INTEL_TDX_HOST
1905	bool "Intel Trust Domain Extensions (TDX) host support"
1906	depends on CPU_SUP_INTEL
1907	depends on X86_64
1908	depends on KVM_INTEL
1909	depends on X86_X2APIC
1910	select ARCH_KEEP_MEMBLOCK
1911	depends on CONTIG_ALLOC
1912	depends on X86_MCE
1913	help
1914	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1915	  host and certain physical attacks.  This option enables necessary TDX
1916	  support in the host kernel to run confidential VMs.
1917
1918	  If unsure, say N.
1919
1920config EFI
1921	bool "EFI runtime service support"
1922	depends on ACPI
1923	select UCS2_STRING
1924	select EFI_RUNTIME_WRAPPERS
1925	select ARCH_USE_MEMREMAP_PROT
1926	select EFI_RUNTIME_MAP if KEXEC_CORE
1927	help
1928	  This enables the kernel to use EFI runtime services that are
1929	  available (such as the EFI variable services).
1930
1931	  This option is only useful on systems that have EFI firmware.
1932	  In addition, you should use the latest ELILO loader available
1933	  at <http://elilo.sourceforge.net> in order to take advantage
1934	  of EFI runtime services. However, even with this option, the
1935	  resultant kernel should continue to boot on existing non-EFI
1936	  platforms.
1937
1938config EFI_STUB
1939	bool "EFI stub support"
1940	depends on EFI
1941	select RELOCATABLE
1942	help
1943	  This kernel feature allows a bzImage to be loaded directly
1944	  by EFI firmware without the use of a bootloader.
1945
1946	  See Documentation/admin-guide/efi-stub.rst for more information.
1947
1948config EFI_HANDOVER_PROTOCOL
1949	bool "EFI handover protocol (DEPRECATED)"
1950	depends on EFI_STUB
1951	default y
1952	help
1953	  Select this in order to include support for the deprecated EFI
1954	  handover protocol, which defines alternative entry points into the
1955	  EFI stub.  This is a practice that has no basis in the UEFI
1956	  specification, and requires a priori knowledge on the part of the
1957	  bootloader about Linux/x86 specific ways of passing the command line
1958	  and initrd, and where in memory those assets may be loaded.
1959
1960	  If in doubt, say Y. Even though the corresponding support is not
1961	  present in upstream GRUB or other bootloaders, most distros build
1962	  GRUB with numerous downstream patches applied, and may rely on the
1963	  handover protocol as as result.
1964
1965config EFI_MIXED
1966	bool "EFI mixed-mode support"
1967	depends on EFI_STUB && X86_64
1968	help
1969	  Enabling this feature allows a 64-bit kernel to be booted
1970	  on a 32-bit firmware, provided that your CPU supports 64-bit
1971	  mode.
1972
1973	  Note that it is not possible to boot a mixed-mode enabled
1974	  kernel via the EFI boot stub - a bootloader that supports
1975	  the EFI handover protocol must be used.
1976
1977	  If unsure, say N.
1978
1979config EFI_RUNTIME_MAP
1980	bool "Export EFI runtime maps to sysfs" if EXPERT
1981	depends on EFI
1982	help
1983	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1984	  That memory map is required by the 2nd kernel to set up EFI virtual
1985	  mappings after kexec, but can also be used for debugging purposes.
1986
1987	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1988
1989source "kernel/Kconfig.hz"
1990
1991config ARCH_SUPPORTS_KEXEC
1992	def_bool y
1993
1994config ARCH_SUPPORTS_KEXEC_FILE
1995	def_bool X86_64
1996
1997config ARCH_SELECTS_KEXEC_FILE
1998	def_bool y
1999	depends on KEXEC_FILE
2000	select HAVE_IMA_KEXEC if IMA
2001
2002config ARCH_SUPPORTS_KEXEC_PURGATORY
2003	def_bool y
2004
2005config ARCH_SUPPORTS_KEXEC_SIG
2006	def_bool y
2007
2008config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2009	def_bool y
2010
2011config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2012	def_bool y
2013
2014config ARCH_SUPPORTS_KEXEC_JUMP
2015	def_bool y
2016
2017config ARCH_SUPPORTS_KEXEC_HANDOVER
2018	def_bool X86_64
2019
2020config ARCH_SUPPORTS_CRASH_DUMP
2021	def_bool X86_64 || (X86_32 && HIGHMEM)
2022
2023config ARCH_DEFAULT_CRASH_DUMP
2024	def_bool y
2025
2026config ARCH_SUPPORTS_CRASH_HOTPLUG
2027	def_bool y
2028
2029config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2030	def_bool CRASH_RESERVE
2031
2032config PHYSICAL_START
2033	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2034	default "0x1000000"
2035	help
2036	  This gives the physical address where the kernel is loaded.
2037
2038	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2039	  will decompress itself to above physical address and run from there.
2040	  Otherwise, bzImage will run from the address where it has been loaded
2041	  by the boot loader. The only exception is if it is loaded below the
2042	  above physical address, in which case it will relocate itself there.
2043
2044	  In normal kdump cases one does not have to set/change this option
2045	  as now bzImage can be compiled as a completely relocatable image
2046	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2047	  address. This option is mainly useful for the folks who don't want
2048	  to use a bzImage for capturing the crash dump and want to use a
2049	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2050	  to be specifically compiled to run from a specific memory area
2051	  (normally a reserved region) and this option comes handy.
2052
2053	  So if you are using bzImage for capturing the crash dump,
2054	  leave the value here unchanged to 0x1000000 and set
2055	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2056	  for capturing the crash dump change this value to start of
2057	  the reserved region.  In other words, it can be set based on
2058	  the "X" value as specified in the "crashkernel=YM@XM"
2059	  command line boot parameter passed to the panic-ed
2060	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2061	  for more details about crash dumps.
2062
2063	  Usage of bzImage for capturing the crash dump is recommended as
2064	  one does not have to build two kernels. Same kernel can be used
2065	  as production kernel and capture kernel. Above option should have
2066	  gone away after relocatable bzImage support is introduced. But it
2067	  is present because there are users out there who continue to use
2068	  vmlinux for dump capture. This option should go away down the
2069	  line.
2070
2071	  Don't change this unless you know what you are doing.
2072
2073config RELOCATABLE
2074	bool "Build a relocatable kernel"
2075	default y
2076	help
2077	  This builds a kernel image that retains relocation information
2078	  so it can be loaded someplace besides the default 1MB.
2079	  The relocations tend to make the kernel binary about 10% larger,
2080	  but are discarded at runtime.
2081
2082	  One use is for the kexec on panic case where the recovery kernel
2083	  must live at a different physical address than the primary
2084	  kernel.
2085
2086	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2087	  it has been loaded at and the compile time physical address
2088	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2089
2090config RANDOMIZE_BASE
2091	bool "Randomize the address of the kernel image (KASLR)"
2092	depends on RELOCATABLE
2093	default y
2094	help
2095	  In support of Kernel Address Space Layout Randomization (KASLR),
2096	  this randomizes the physical address at which the kernel image
2097	  is decompressed and the virtual address where the kernel
2098	  image is mapped, as a security feature that deters exploit
2099	  attempts relying on knowledge of the location of kernel
2100	  code internals.
2101
2102	  On 64-bit, the kernel physical and virtual addresses are
2103	  randomized separately. The physical address will be anywhere
2104	  between 16MB and the top of physical memory (up to 64TB). The
2105	  virtual address will be randomized from 16MB up to 1GB (9 bits
2106	  of entropy). Note that this also reduces the memory space
2107	  available to kernel modules from 1.5GB to 1GB.
2108
2109	  On 32-bit, the kernel physical and virtual addresses are
2110	  randomized together. They will be randomized from 16MB up to
2111	  512MB (8 bits of entropy).
2112
2113	  Entropy is generated using the RDRAND instruction if it is
2114	  supported. If RDTSC is supported, its value is mixed into
2115	  the entropy pool as well. If neither RDRAND nor RDTSC are
2116	  supported, then entropy is read from the i8254 timer. The
2117	  usable entropy is limited by the kernel being built using
2118	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2119	  minimum of 2MB. As a result, only 10 bits of entropy are
2120	  theoretically possible, but the implementations are further
2121	  limited due to memory layouts.
2122
2123	  If unsure, say Y.
2124
2125# Relocation on x86 needs some additional build support
2126config X86_NEED_RELOCS
2127	def_bool y
2128	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2129	select ARCH_VMLINUX_NEEDS_RELOCS
2130
2131config PHYSICAL_ALIGN
2132	hex "Alignment value to which kernel should be aligned"
2133	default "0x200000"
2134	range 0x2000 0x1000000 if X86_32
2135	range 0x200000 0x1000000 if X86_64
2136	help
2137	  This value puts the alignment restrictions on physical address
2138	  where kernel is loaded and run from. Kernel is compiled for an
2139	  address which meets above alignment restriction.
2140
2141	  If bootloader loads the kernel at a non-aligned address and
2142	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2143	  address aligned to above value and run from there.
2144
2145	  If bootloader loads the kernel at a non-aligned address and
2146	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2147	  load address and decompress itself to the address it has been
2148	  compiled for and run from there. The address for which kernel is
2149	  compiled already meets above alignment restrictions. Hence the
2150	  end result is that kernel runs from a physical address meeting
2151	  above alignment restrictions.
2152
2153	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2154	  this value must be a multiple of 0x200000.
2155
2156	  Don't change this unless you know what you are doing.
2157
2158config RANDOMIZE_MEMORY
2159	bool "Randomize the kernel memory sections"
2160	depends on X86_64
2161	depends on RANDOMIZE_BASE
2162	default RANDOMIZE_BASE
2163	help
2164	  Randomizes the base virtual address of kernel memory sections
2165	  (physical memory mapping, vmalloc & vmemmap). This security feature
2166	  makes exploits relying on predictable memory locations less reliable.
2167
2168	  The order of allocations remains unchanged. Entropy is generated in
2169	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2170	  configuration have in average 30,000 different possible virtual
2171	  addresses for each memory section.
2172
2173	  If unsure, say Y.
2174
2175config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2176	hex "Physical memory mapping padding" if EXPERT
2177	depends on RANDOMIZE_MEMORY
2178	default "0xa" if MEMORY_HOTPLUG
2179	default "0x0"
2180	range 0x1 0x40 if MEMORY_HOTPLUG
2181	range 0x0 0x40
2182	help
2183	  Define the padding in terabytes added to the existing physical
2184	  memory size during kernel memory randomization. It is useful
2185	  for memory hotplug support but reduces the entropy available for
2186	  address randomization.
2187
2188	  If unsure, leave at the default value.
2189
2190config ADDRESS_MASKING
2191	bool "Linear Address Masking support"
2192	depends on X86_64
2193	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2194	help
2195	  Linear Address Masking (LAM) modifies the checking that is applied
2196	  to 64-bit linear addresses, allowing software to use of the
2197	  untranslated address bits for metadata.
2198
2199	  The capability can be used for efficient address sanitizers (ASAN)
2200	  implementation and for optimizations in JITs.
2201
2202config HOTPLUG_CPU
2203	def_bool y
2204	depends on SMP
2205
2206config COMPAT_VDSO
2207	def_bool n
2208	prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)"
2209	depends on COMPAT_32
2210	help
2211	  Certain buggy versions of glibc will crash if they are
2212	  presented with a 32-bit vDSO that is not mapped at the address
2213	  indicated in its segment table.
2214
2215	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2216	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2217	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2218	  the only released version with the bug, but OpenSUSE 9
2219	  contains a buggy "glibc 2.3.2".
2220
2221	  The symptom of the bug is that everything crashes on startup, saying:
2222	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2223
2224	  Saying Y here changes the default value of the vdso32 boot
2225	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2226	  This works around the glibc bug but hurts performance.
2227
2228	  If unsure, say N: if you are compiling your own kernel, you
2229	  are unlikely to be using a buggy version of glibc.
2230
2231choice
2232	prompt "vsyscall table for legacy applications"
2233	depends on X86_64
2234	default LEGACY_VSYSCALL_XONLY
2235	help
2236	  Legacy user code that does not know how to find the vDSO expects
2237	  to be able to issue three syscalls by calling fixed addresses in
2238	  kernel space. Since this location is not randomized with ASLR,
2239	  it can be used to assist security vulnerability exploitation.
2240
2241	  This setting can be changed at boot time via the kernel command
2242	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2243	  is deprecated and can only be enabled using the kernel command
2244	  line.
2245
2246	  On a system with recent enough glibc (2.14 or newer) and no
2247	  static binaries, you can say None without a performance penalty
2248	  to improve security.
2249
2250	  If unsure, select "Emulate execution only".
2251
2252	config LEGACY_VSYSCALL_XONLY
2253		bool "Emulate execution only"
2254		help
2255		  The kernel traps and emulates calls into the fixed vsyscall
2256		  address mapping and does not allow reads.  This
2257		  configuration is recommended when userspace might use the
2258		  legacy vsyscall area but support for legacy binary
2259		  instrumentation of legacy code is not needed.  It mitigates
2260		  certain uses of the vsyscall area as an ASLR-bypassing
2261		  buffer.
2262
2263	config LEGACY_VSYSCALL_NONE
2264		bool "None"
2265		help
2266		  There will be no vsyscall mapping at all. This will
2267		  eliminate any risk of ASLR bypass due to the vsyscall
2268		  fixed address mapping. Attempts to use the vsyscalls
2269		  will be reported to dmesg, so that either old or
2270		  malicious userspace programs can be identified.
2271
2272endchoice
2273
2274config CMDLINE_BOOL
2275	bool "Built-in kernel command line"
2276	help
2277	  Allow for specifying boot arguments to the kernel at
2278	  build time.  On some systems (e.g. embedded ones), it is
2279	  necessary or convenient to provide some or all of the
2280	  kernel boot arguments with the kernel itself (that is,
2281	  to not rely on the boot loader to provide them.)
2282
2283	  To compile command line arguments into the kernel,
2284	  set this option to 'Y', then fill in the
2285	  boot arguments in CONFIG_CMDLINE.
2286
2287	  Systems with fully functional boot loaders (i.e. non-embedded)
2288	  should leave this option set to 'N'.
2289
2290config CMDLINE
2291	string "Built-in kernel command string"
2292	depends on CMDLINE_BOOL
2293	default ""
2294	help
2295	  Enter arguments here that should be compiled into the kernel
2296	  image and used at boot time.  If the boot loader provides a
2297	  command line at boot time, it is appended to this string to
2298	  form the full kernel command line, when the system boots.
2299
2300	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2301	  change this behavior.
2302
2303	  In most cases, the command line (whether built-in or provided
2304	  by the boot loader) should specify the device for the root
2305	  file system.
2306
2307config CMDLINE_OVERRIDE
2308	bool "Built-in command line overrides boot loader arguments"
2309	depends on CMDLINE_BOOL && CMDLINE != ""
2310	help
2311	  Set this option to 'Y' to have the kernel ignore the boot loader
2312	  command line, and use ONLY the built-in command line.
2313
2314	  This is used to work around broken boot loaders.  This should
2315	  be set to 'N' under normal conditions.
2316
2317config MODIFY_LDT_SYSCALL
2318	bool "Enable the LDT (local descriptor table)" if EXPERT
2319	default y
2320	help
2321	  Linux can allow user programs to install a per-process x86
2322	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2323	  call.  This is required to run 16-bit or segmented code such as
2324	  DOSEMU or some Wine programs.  It is also used by some very old
2325	  threading libraries.
2326
2327	  Enabling this feature adds a small amount of overhead to
2328	  context switches and increases the low-level kernel attack
2329	  surface.  Disabling it removes the modify_ldt(2) system call.
2330
2331	  Saying 'N' here may make sense for embedded or server kernels.
2332
2333config STRICT_SIGALTSTACK_SIZE
2334	bool "Enforce strict size checking for sigaltstack"
2335	depends on DYNAMIC_SIGFRAME
2336	help
2337	  For historical reasons MINSIGSTKSZ is a constant which became
2338	  already too small with AVX512 support. Add a mechanism to
2339	  enforce strict checking of the sigaltstack size against the
2340	  real size of the FPU frame. This option enables the check
2341	  by default. It can also be controlled via the kernel command
2342	  line option 'strict_sas_size' independent of this config
2343	  switch. Enabling it might break existing applications which
2344	  allocate a too small sigaltstack but 'work' because they
2345	  never get a signal delivered.
2346
2347	  Say 'N' unless you want to really enforce this check.
2348
2349config CFI_AUTO_DEFAULT
2350	bool "Attempt to use FineIBT by default at boot time"
2351	depends on FINEIBT
2352	depends on !RUST || RUSTC_VERSION >= 108800
2353	default y
2354	help
2355	  Attempt to use FineIBT by default at boot time. If enabled,
2356	  this is the same as booting with "cfi=auto". If disabled,
2357	  this is the same as booting with "cfi=kcfi".
2358
2359source "kernel/livepatch/Kconfig"
2360
2361config X86_BUS_LOCK_DETECT
2362	bool "Split Lock Detect and Bus Lock Detect support"
2363	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2364	default y
2365	help
2366	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2367	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2368
2369endmenu
2370
2371config CC_HAS_NAMED_AS
2372	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2373	depends on CC_IS_GCC
2374
2375#
2376# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2377# are incompatible with named address spaces with GCC < 13.3
2378# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2379#
2380
2381config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2382	def_bool y
2383	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2384	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2385
2386config USE_X86_SEG_SUPPORT
2387	def_bool CC_HAS_NAMED_AS
2388	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2389
2390config CC_HAS_SLS
2391	def_bool $(cc-option,-mharden-sls=all)
2392
2393config CC_HAS_RETURN_THUNK
2394	def_bool $(cc-option,-mfunction-return=thunk-extern)
2395
2396config CC_HAS_ENTRY_PADDING
2397	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2398
2399config CC_HAS_KCFI_ARITY
2400	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2401	depends on CC_IS_CLANG && !RUST
2402
2403config FUNCTION_PADDING_CFI
2404	int
2405	default 59 if FUNCTION_ALIGNMENT_64B
2406	default 27 if FUNCTION_ALIGNMENT_32B
2407	default 11 if FUNCTION_ALIGNMENT_16B
2408	default  3 if FUNCTION_ALIGNMENT_8B
2409	default  0
2410
2411# Basically: FUNCTION_ALIGNMENT - 5*CFI
2412# except Kconfig can't do arithmetic :/
2413config FUNCTION_PADDING_BYTES
2414	int
2415	default FUNCTION_PADDING_CFI if CFI
2416	default FUNCTION_ALIGNMENT
2417
2418config CALL_PADDING
2419	def_bool n
2420	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2421	select FUNCTION_ALIGNMENT_16B
2422
2423config FINEIBT
2424	def_bool y
2425	depends on X86_KERNEL_IBT && CFI && MITIGATION_RETPOLINE
2426	select CALL_PADDING
2427
2428config FINEIBT_BHI
2429	def_bool y
2430	depends on FINEIBT && CC_HAS_KCFI_ARITY
2431
2432config HAVE_CALL_THUNKS
2433	def_bool y
2434	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2435
2436config CALL_THUNKS
2437	def_bool n
2438	select CALL_PADDING
2439
2440config PREFIX_SYMBOLS
2441	def_bool y
2442	depends on CALL_PADDING && !CFI
2443
2444menuconfig CPU_MITIGATIONS
2445	bool "Mitigations for CPU vulnerabilities"
2446	default y
2447	help
2448	  Say Y here to enable options which enable mitigations for hardware
2449	  vulnerabilities (usually related to speculative execution).
2450	  Mitigations can be disabled or restricted to SMT systems at runtime
2451	  via the "mitigations" kernel parameter.
2452
2453	  If you say N, all mitigations will be disabled.  This CANNOT be
2454	  overridden at runtime.
2455
2456	  Say 'Y', unless you really know what you are doing.
2457
2458if CPU_MITIGATIONS
2459
2460config MITIGATION_PAGE_TABLE_ISOLATION
2461	bool "Remove the kernel mapping in user mode"
2462	default y
2463	depends on (X86_64 || X86_PAE)
2464	help
2465	  This feature reduces the number of hardware side channels by
2466	  ensuring that the majority of kernel addresses are not mapped
2467	  into userspace.
2468
2469	  See Documentation/arch/x86/pti.rst for more details.
2470
2471config MITIGATION_RETPOLINE
2472	bool "Avoid speculative indirect branches in kernel"
2473	select OBJTOOL if HAVE_OBJTOOL
2474	default y
2475	help
2476	  Compile kernel with the retpoline compiler options to guard against
2477	  kernel-to-user data leaks by avoiding speculative indirect
2478	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2479	  support for full protection. The kernel may run slower.
2480
2481config MITIGATION_RETHUNK
2482	bool "Enable return-thunks"
2483	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2484	select OBJTOOL if HAVE_OBJTOOL
2485	default y if X86_64
2486	help
2487	  Compile the kernel with the return-thunks compiler option to guard
2488	  against kernel-to-user data leaks by avoiding return speculation.
2489	  Requires a compiler with -mfunction-return=thunk-extern
2490	  support for full protection. The kernel may run slower.
2491
2492config MITIGATION_UNRET_ENTRY
2493	bool "Enable UNRET on kernel entry"
2494	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2495	default y
2496	help
2497	  Compile the kernel with support for the retbleed=unret mitigation.
2498
2499config MITIGATION_CALL_DEPTH_TRACKING
2500	bool "Mitigate RSB underflow with call depth tracking"
2501	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2502	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2503	select CALL_THUNKS
2504	default y
2505	help
2506	  Compile the kernel with call depth tracking to mitigate the Intel
2507	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2508	  by default and needs to be enabled on the kernel command line via the
2509	  retbleed=stuff option. For non-affected systems the overhead of this
2510	  option is marginal as the call depth tracking is using run-time
2511	  generated call thunks in a compiler generated padding area and call
2512	  patching. This increases text size by ~5%. For non affected systems
2513	  this space is unused. On affected SKL systems this results in a
2514	  significant performance gain over the IBRS mitigation.
2515
2516config CALL_THUNKS_DEBUG
2517	bool "Enable call thunks and call depth tracking debugging"
2518	depends on MITIGATION_CALL_DEPTH_TRACKING
2519	select FUNCTION_ALIGNMENT_32B
2520	default n
2521	help
2522	  Enable call/ret counters for imbalance detection and build in
2523	  a noisy dmesg about callthunks generation and call patching for
2524	  trouble shooting. The debug prints need to be enabled on the
2525	  kernel command line with 'debug-callthunks'.
2526	  Only enable this when you are debugging call thunks as this
2527	  creates a noticeable runtime overhead. If unsure say N.
2528
2529config MITIGATION_IBPB_ENTRY
2530	bool "Enable IBPB on kernel entry"
2531	depends on CPU_SUP_AMD && X86_64
2532	default y
2533	help
2534	  Compile the kernel with support for the retbleed=ibpb and
2535	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2536
2537config MITIGATION_IBRS_ENTRY
2538	bool "Enable IBRS on kernel entry"
2539	depends on CPU_SUP_INTEL && X86_64
2540	default y
2541	help
2542	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2543	  This mitigates both spectre_v2 and retbleed at great cost to
2544	  performance.
2545
2546config MITIGATION_SRSO
2547	bool "Mitigate speculative RAS overflow on AMD"
2548	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2549	default y
2550	help
2551	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2552
2553config MITIGATION_SLS
2554	bool "Mitigate Straight-Line-Speculation"
2555	depends on CC_HAS_SLS && X86_64
2556	select OBJTOOL if HAVE_OBJTOOL
2557	default n
2558	help
2559	  Compile the kernel with straight-line-speculation options to guard
2560	  against straight line speculation. The kernel image might be slightly
2561	  larger.
2562
2563config MITIGATION_GDS
2564	bool "Mitigate Gather Data Sampling"
2565	depends on CPU_SUP_INTEL
2566	default y
2567	help
2568	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2569	  vulnerability which allows unprivileged speculative access to data
2570	  which was previously stored in vector registers. The attacker uses gather
2571	  instructions to infer the stale vector register data.
2572
2573config MITIGATION_RFDS
2574	bool "RFDS Mitigation"
2575	depends on CPU_SUP_INTEL
2576	default y
2577	help
2578	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2579	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2580	  allows unprivileged speculative access to stale data previously
2581	  stored in floating point, vector and integer registers.
2582	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2583
2584config MITIGATION_SPECTRE_BHI
2585	bool "Mitigate Spectre-BHB (Branch History Injection)"
2586	depends on CPU_SUP_INTEL
2587	default y
2588	help
2589	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2590	  where the branch history buffer is poisoned to speculatively steer
2591	  indirect branches.
2592	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2593
2594config MITIGATION_MDS
2595	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2596	depends on CPU_SUP_INTEL
2597	default y
2598	help
2599	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2600	  a hardware vulnerability which allows unprivileged speculative access
2601	  to data which is available in various CPU internal buffers.
2602	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2603
2604config MITIGATION_TAA
2605	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2606	depends on CPU_SUP_INTEL
2607	default y
2608	help
2609	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2610	  vulnerability that allows unprivileged speculative access to data
2611	  which is available in various CPU internal buffers by using
2612	  asynchronous aborts within an Intel TSX transactional region.
2613	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2614
2615config MITIGATION_MMIO_STALE_DATA
2616	bool "Mitigate MMIO Stale Data hardware bug"
2617	depends on CPU_SUP_INTEL
2618	default y
2619	help
2620	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2621	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2622	  vulnerabilities that can expose data. The vulnerabilities require the
2623	  attacker to have access to MMIO.
2624	  See also
2625	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2626
2627config MITIGATION_L1TF
2628	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2629	depends on CPU_SUP_INTEL
2630	default y
2631	help
2632	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2633	  hardware vulnerability which allows unprivileged speculative access to data
2634	  available in the Level 1 Data Cache.
2635	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2636
2637config MITIGATION_RETBLEED
2638	bool "Mitigate RETBleed hardware bug"
2639	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2640	default y
2641	help
2642	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2643	  with Return Instructions) vulnerability.  RETBleed is a speculative
2644	  execution attack which takes advantage of microarchitectural behavior
2645	  in many modern microprocessors, similar to Spectre v2. An
2646	  unprivileged attacker can use these flaws to bypass conventional
2647	  memory security restrictions to gain read access to privileged memory
2648	  that would otherwise be inaccessible.
2649
2650config MITIGATION_SPECTRE_V1
2651	bool "Mitigate SPECTRE V1 hardware bug"
2652	default y
2653	help
2654	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2655	  class of side channel attacks that takes advantage of speculative
2656	  execution that bypasses conditional branch instructions used for
2657	  memory access bounds check.
2658	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2659
2660config MITIGATION_SPECTRE_V2
2661	bool "Mitigate SPECTRE V2 hardware bug"
2662	default y
2663	help
2664	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2665	  V2 is a class of side channel attacks that takes advantage of
2666	  indirect branch predictors inside the processor. In Spectre variant 2
2667	  attacks, the attacker can steer speculative indirect branches in the
2668	  victim to gadget code by poisoning the branch target buffer of a CPU
2669	  used for predicting indirect branch addresses.
2670	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2671
2672config MITIGATION_SRBDS
2673	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2674	depends on CPU_SUP_INTEL
2675	default y
2676	help
2677	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2678	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2679	  Sampling (MDS) techniques to infer values returned from special
2680	  register accesses. An unprivileged user can extract values returned
2681	  from RDRAND and RDSEED executed on another core or sibling thread
2682	  using MDS techniques.
2683	  See also
2684	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2685
2686config MITIGATION_SSB
2687	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2688	default y
2689	help
2690	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2691	  hardware security vulnerability and its exploitation takes advantage
2692	  of speculative execution in a similar way to the Meltdown and Spectre
2693	  security vulnerabilities.
2694
2695config MITIGATION_ITS
2696	bool "Enable Indirect Target Selection mitigation"
2697	depends on CPU_SUP_INTEL && X86_64
2698	depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK
2699	select EXECMEM
2700	default y
2701	help
2702	  Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in
2703	  BPU on some Intel CPUs that may allow Spectre V2 style attacks. If
2704	  disabled, mitigation cannot be enabled via cmdline.
2705	  See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst>
2706
2707config MITIGATION_TSA
2708	bool "Mitigate Transient Scheduler Attacks"
2709	depends on CPU_SUP_AMD
2710	default y
2711	help
2712	  Enable mitigation for Transient Scheduler Attacks. TSA is a hardware
2713	  security vulnerability on AMD CPUs which can lead to forwarding of
2714	  invalid info to subsequent instructions and thus can affect their
2715	  timing and thereby cause a leakage.
2716
2717config MITIGATION_VMSCAPE
2718	bool "Mitigate VMSCAPE"
2719	depends on KVM
2720	default y
2721	help
2722	  Enable mitigation for VMSCAPE attacks. VMSCAPE is a hardware security
2723	  vulnerability on Intel and AMD CPUs that may allow a guest to do
2724	  Spectre v2 style attacks on userspace hypervisor.
2725endif
2726
2727config ARCH_HAS_ADD_PAGES
2728	def_bool y
2729	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2730
2731menu "Power management and ACPI options"
2732
2733config ARCH_HIBERNATION_HEADER
2734	def_bool y
2735	depends on HIBERNATION
2736
2737source "kernel/power/Kconfig"
2738
2739source "drivers/acpi/Kconfig"
2740
2741config X86_APM_BOOT
2742	def_bool y
2743	depends on APM
2744
2745menuconfig APM
2746	tristate "APM (Advanced Power Management) BIOS support"
2747	depends on X86_32 && PM_SLEEP
2748	help
2749	  APM is a BIOS specification for saving power using several different
2750	  techniques. This is mostly useful for battery powered laptops with
2751	  APM compliant BIOSes. If you say Y here, the system time will be
2752	  reset after a RESUME operation, the /proc/apm device will provide
2753	  battery status information, and user-space programs will receive
2754	  notification of APM "events" (e.g. battery status change).
2755
2756	  If you select "Y" here, you can disable actual use of the APM
2757	  BIOS by passing the "apm=off" option to the kernel at boot time.
2758
2759	  Note that the APM support is almost completely disabled for
2760	  machines with more than one CPU.
2761
2762	  In order to use APM, you will need supporting software. For location
2763	  and more information, read <file:Documentation/power/apm-acpi.rst>
2764	  and the Battery Powered Linux mini-HOWTO, available from
2765	  <http://www.tldp.org/docs.html#howto>.
2766
2767	  This driver does not spin down disk drives (see the hdparm(8)
2768	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2769	  VESA-compliant "green" monitors.
2770
2771	  Generally, if you don't have a battery in your machine, there isn't
2772	  much point in using this driver and you should say N. If you get
2773	  random kernel OOPSes or reboots that don't seem to be related to
2774	  anything, try disabling/enabling this option (or disabling/enabling
2775	  APM in your BIOS).
2776
2777	  Some other things you should try when experiencing seemingly random,
2778	  "weird" problems:
2779
2780	  1) make sure that you have enough swap space and that it is
2781	  enabled.
2782	  2) pass the "idle=poll" option to the kernel
2783	  3) switch on floating point emulation in the kernel and pass
2784	  the "no387" option to the kernel
2785	  4) pass the "floppy=nodma" option to the kernel
2786	  5) pass the "mem=4M" option to the kernel (thereby disabling
2787	  all but the first 4 MB of RAM)
2788	  6) make sure that the CPU is not over clocked.
2789	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2790	  8) disable the cache from your BIOS settings
2791	  9) install a fan for the video card or exchange video RAM
2792	  10) install a better fan for the CPU
2793	  11) exchange RAM chips
2794	  12) exchange the motherboard.
2795
2796	  To compile this driver as a module, choose M here: the
2797	  module will be called apm.
2798
2799if APM
2800
2801config APM_IGNORE_USER_SUSPEND
2802	bool "Ignore USER SUSPEND"
2803	help
2804	  This option will ignore USER SUSPEND requests. On machines with a
2805	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2806	  series notebooks, it is necessary to say Y because of a BIOS bug.
2807
2808config APM_DO_ENABLE
2809	bool "Enable PM at boot time"
2810	help
2811	  Enable APM features at boot time. From page 36 of the APM BIOS
2812	  specification: "When disabled, the APM BIOS does not automatically
2813	  power manage devices, enter the Standby State, enter the Suspend
2814	  State, or take power saving steps in response to CPU Idle calls."
2815	  This driver will make CPU Idle calls when Linux is idle (unless this
2816	  feature is turned off -- see "Do CPU IDLE calls", below). This
2817	  should always save battery power, but more complicated APM features
2818	  will be dependent on your BIOS implementation. You may need to turn
2819	  this option off if your computer hangs at boot time when using APM
2820	  support, or if it beeps continuously instead of suspending. Turn
2821	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2822	  T400CDT. This is off by default since most machines do fine without
2823	  this feature.
2824
2825config APM_CPU_IDLE
2826	depends on CPU_IDLE
2827	bool "Make CPU Idle calls when idle"
2828	help
2829	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2830	  On some machines, this can activate improved power savings, such as
2831	  a slowed CPU clock rate, when the machine is idle. These idle calls
2832	  are made after the idle loop has run for some length of time (e.g.,
2833	  333 mS). On some machines, this will cause a hang at boot time or
2834	  whenever the CPU becomes idle. (On machines with more than one CPU,
2835	  this option does nothing.)
2836
2837config APM_DISPLAY_BLANK
2838	bool "Enable console blanking using APM"
2839	help
2840	  Enable console blanking using the APM. Some laptops can use this to
2841	  turn off the LCD backlight when the screen blanker of the Linux
2842	  virtual console blanks the screen. Note that this is only used by
2843	  the virtual console screen blanker, and won't turn off the backlight
2844	  when using the X Window system. This also doesn't have anything to
2845	  do with your VESA-compliant power-saving monitor. Further, this
2846	  option doesn't work for all laptops -- it might not turn off your
2847	  backlight at all, or it might print a lot of errors to the console,
2848	  especially if you are using gpm.
2849
2850config APM_ALLOW_INTS
2851	bool "Allow interrupts during APM BIOS calls"
2852	help
2853	  Normally we disable external interrupts while we are making calls to
2854	  the APM BIOS as a measure to lessen the effects of a badly behaving
2855	  BIOS implementation.  The BIOS should reenable interrupts if it
2856	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2857	  many of the newer IBM Thinkpads.  If you experience hangs when you
2858	  suspend, try setting this to Y.  Otherwise, say N.
2859
2860endif # APM
2861
2862source "drivers/cpufreq/Kconfig"
2863
2864source "drivers/cpuidle/Kconfig"
2865
2866source "drivers/idle/Kconfig"
2867
2868endmenu
2869
2870menu "Bus options (PCI etc.)"
2871
2872choice
2873	prompt "PCI access mode"
2874	depends on X86_32 && PCI
2875	default PCI_GOANY
2876	help
2877	  On PCI systems, the BIOS can be used to detect the PCI devices and
2878	  determine their configuration. However, some old PCI motherboards
2879	  have BIOS bugs and may crash if this is done. Also, some embedded
2880	  PCI-based systems don't have any BIOS at all. Linux can also try to
2881	  detect the PCI hardware directly without using the BIOS.
2882
2883	  With this option, you can specify how Linux should detect the
2884	  PCI devices. If you choose "BIOS", the BIOS will be used,
2885	  if you choose "Direct", the BIOS won't be used, and if you
2886	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2887	  If you choose "Any", the kernel will try MMCONFIG, then the
2888	  direct access method and falls back to the BIOS if that doesn't
2889	  work. If unsure, go with the default, which is "Any".
2890
2891config PCI_GOBIOS
2892	bool "BIOS"
2893
2894config PCI_GOMMCONFIG
2895	bool "MMConfig"
2896
2897config PCI_GODIRECT
2898	bool "Direct"
2899
2900config PCI_GOOLPC
2901	bool "OLPC XO-1"
2902	depends on OLPC
2903
2904config PCI_GOANY
2905	bool "Any"
2906
2907endchoice
2908
2909config PCI_BIOS
2910	def_bool y
2911	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2912
2913# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2914config PCI_DIRECT
2915	def_bool y
2916	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2917
2918config PCI_MMCONFIG
2919	bool "Support mmconfig PCI config space access" if X86_64
2920	default y
2921	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2922	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2923	help
2924	  Add support for accessing the PCI configuration space as a memory
2925	  mapped area. It is the recommended method if the system supports
2926	  this (it must have PCI Express and ACPI for it to be available).
2927
2928	  In the unlikely case that enabling this configuration option causes
2929	  problems, the mechanism can be switched off with the 'pci=nommconf'
2930	  command line parameter.
2931
2932	  Say N only if you are sure that your platform does not support this
2933	  access method or you have problems caused by it.
2934
2935	  Say Y otherwise.
2936
2937config PCI_OLPC
2938	def_bool y
2939	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2940
2941config PCI_XEN
2942	def_bool y
2943	depends on PCI && XEN
2944
2945config MMCONF_FAM10H
2946	def_bool y
2947	depends on X86_64 && PCI_MMCONFIG && ACPI
2948
2949config PCI_CNB20LE_QUIRK
2950	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2951	depends on X86_32 && PCI
2952	help
2953	  Read the PCI windows out of the CNB20LE host bridge. This allows
2954	  PCI hotplug to work on systems with the CNB20LE chipset which do
2955	  not have ACPI.
2956
2957	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2958	  most probably only for Pentium III.
2959
2960	  To find out if you have such a chipset, search for a PCI device with
2961	  1166:0009 PCI IDs, for example by executing
2962		lspci -nn | grep '1166:0009'
2963	  The code is inactive if there is none.
2964
2965	  There's no public spec for this chipset, and this functionality
2966	  is known to be incomplete.
2967
2968	  You should say N unless you know you need this.
2969
2970config ISA_BUS
2971	bool "ISA bus support on modern systems" if EXPERT
2972	help
2973	  Expose ISA bus device drivers and options available for selection and
2974	  configuration. Enable this option if your target machine has an ISA
2975	  bus. ISA is an older system, displaced by PCI and newer bus
2976	  architectures -- if your target machine is modern, it probably does
2977	  not have an ISA bus.
2978
2979	  If unsure, say N.
2980
2981# x86_64 have no ISA slots, but can have ISA-style DMA.
2982config ISA_DMA_API
2983	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2984	default y
2985	help
2986	  Enables ISA-style DMA support for devices requiring such controllers.
2987	  If unsure, say Y.
2988
2989if X86_32
2990
2991config ISA
2992	bool "ISA support"
2993	help
2994	  Find out whether you have ISA slots on your motherboard.  ISA is the
2995	  name of a bus system, i.e. the way the CPU talks to the other stuff
2996	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2997	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2998	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2999
3000config SCx200
3001	tristate "NatSemi SCx200 support"
3002	help
3003	  This provides basic support for National Semiconductor's
3004	  (now AMD's) Geode processors.  The driver probes for the
3005	  PCI-IDs of several on-chip devices, so its a good dependency
3006	  for other scx200_* drivers.
3007
3008	  If compiled as a module, the driver is named scx200.
3009
3010config SCx200HR_TIMER
3011	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
3012	depends on SCx200
3013	default y
3014	help
3015	  This driver provides a clocksource built upon the on-chip
3016	  27MHz high-resolution timer.  Its also a workaround for
3017	  NSC Geode SC-1100's buggy TSC, which loses time when the
3018	  processor goes idle (as is done by the scheduler).  The
3019	  other workaround is idle=poll boot option.
3020
3021config OLPC
3022	bool "One Laptop Per Child support"
3023	depends on !X86_PAE
3024	select GPIOLIB
3025	select OF
3026	select OF_PROMTREE
3027	select IRQ_DOMAIN
3028	select OLPC_EC
3029	help
3030	  Add support for detecting the unique features of the OLPC
3031	  XO hardware.
3032
3033config OLPC_XO1_PM
3034	bool "OLPC XO-1 Power Management"
3035	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3036	help
3037	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3038
3039config OLPC_XO1_RTC
3040	bool "OLPC XO-1 Real Time Clock"
3041	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3042	help
3043	  Add support for the XO-1 real time clock, which can be used as a
3044	  programmable wakeup source.
3045
3046config OLPC_XO1_SCI
3047	bool "OLPC XO-1 SCI extras"
3048	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3049	depends on INPUT=y
3050	select POWER_SUPPLY
3051	help
3052	  Add support for SCI-based features of the OLPC XO-1 laptop:
3053	   - EC-driven system wakeups
3054	   - Power button
3055	   - Ebook switch
3056	   - Lid switch
3057	   - AC adapter status updates
3058	   - Battery status updates
3059
3060config OLPC_XO15_SCI
3061	bool "OLPC XO-1.5 SCI extras"
3062	depends on OLPC && ACPI
3063	select POWER_SUPPLY
3064	help
3065	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3066	   - EC-driven system wakeups
3067	   - AC adapter status updates
3068	   - Battery status updates
3069
3070config GEODE_COMMON
3071	bool
3072
3073config ALIX
3074	bool "PCEngines ALIX System Support (LED setup)"
3075	select GPIOLIB
3076	select GEODE_COMMON
3077	help
3078	  This option enables system support for the PCEngines ALIX.
3079	  At present this just sets up LEDs for GPIO control on
3080	  ALIX2/3/6 boards.  However, other system specific setup should
3081	  get added here.
3082
3083	  Note: You must still enable the drivers for GPIO and LED support
3084	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3085
3086	  Note: You have to set alix.force=1 for boards with Award BIOS.
3087
3088config NET5501
3089	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3090	select GPIOLIB
3091	select GEODE_COMMON
3092	help
3093	  This option enables system support for the Soekris Engineering net5501.
3094
3095config GEOS
3096	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3097	select GPIOLIB
3098	select GEODE_COMMON
3099	depends on DMI
3100	help
3101	  This option enables system support for the Traverse Technologies GEOS.
3102
3103config TS5500
3104	bool "Technologic Systems TS-5500 platform support"
3105	depends on MELAN
3106	select CHECK_SIGNATURE
3107	select NEW_LEDS
3108	select LEDS_CLASS
3109	help
3110	  This option enables system support for the Technologic Systems TS-5500.
3111
3112endif # X86_32
3113
3114config AMD_NB
3115	def_bool y
3116	depends on AMD_NODE
3117
3118config AMD_NODE
3119	def_bool y
3120	depends on CPU_SUP_AMD && PCI
3121
3122endmenu
3123
3124menu "Binary Emulations"
3125
3126config IA32_EMULATION
3127	bool "IA32 Emulation"
3128	depends on X86_64
3129	select ARCH_WANT_OLD_COMPAT_IPC
3130	select BINFMT_ELF
3131	select COMPAT_OLD_SIGACTION
3132	help
3133	  Include code to run legacy 32-bit programs under a
3134	  64-bit kernel. You should likely turn this on, unless you're
3135	  100% sure that you don't have any 32-bit programs left.
3136
3137config IA32_EMULATION_DEFAULT_DISABLED
3138	bool "IA32 emulation disabled by default"
3139	default n
3140	depends on IA32_EMULATION
3141	help
3142	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3143	  processes and access to 32-bit syscalls. If unsure, leave it to its
3144	  default value.
3145
3146config X86_X32_ABI
3147	bool "x32 ABI for 64-bit mode"
3148	depends on X86_64
3149	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3150	# compressed debug sections to x86_x32 properly:
3151	# https://github.com/ClangBuiltLinux/linux/issues/514
3152	# https://github.com/ClangBuiltLinux/linux/issues/1141
3153	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3154	help
3155	  Include code to run binaries for the x32 native 32-bit ABI
3156	  for 64-bit processors.  An x32 process gets access to the
3157	  full 64-bit register file and wide data path while leaving
3158	  pointers at 32 bits for smaller memory footprint.
3159
3160config COMPAT_32
3161	def_bool y
3162	depends on IA32_EMULATION || X86_32
3163	select HAVE_UID16
3164	select OLD_SIGSUSPEND3
3165
3166config COMPAT
3167	def_bool y
3168	depends on IA32_EMULATION || X86_X32_ABI
3169
3170config COMPAT_FOR_U64_ALIGNMENT
3171	def_bool y
3172	depends on COMPAT
3173
3174endmenu
3175
3176config HAVE_ATOMIC_IOMAP
3177	def_bool y
3178	depends on X86_32
3179
3180source "arch/x86/kvm/Kconfig"
3181
3182source "arch/x86/Kconfig.cpufeatures"
3183
3184source "arch/x86/Kconfig.assembler"
3185