xref: /linux/arch/x86/Kconfig (revision 7b49a3fb69e785a2425c8dc7dbd0779a0a4c0eb2)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select HAVE_DEBUG_STACKOVERFLOW
18	select KMAP_LOCAL
19	select MODULES_USE_ELF_REL
20	select OLD_SIGACTION
21	select ARCH_SPLIT_ARG64
22
23config X86_64
24	def_bool y
25	depends on 64BIT
26	# Options that are inherently 64-bit kernel only:
27	select ARCH_HAS_GIGANTIC_PAGE
28	select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
29	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30	select ARCH_SUPPORTS_PER_VMA_LOCK
31	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
32	select HAVE_ARCH_SOFT_DIRTY
33	select MODULES_USE_ELF_RELA
34	select NEED_DMA_MAP_STATE
35	select SWIOTLB
36	select ARCH_HAS_ELFCORE_COMPAT
37	select ZONE_DMA32
38	select EXECMEM if DYNAMIC_FTRACE
39	select ACPI_MRRM if ACPI
40
41config FORCE_DYNAMIC_FTRACE
42	def_bool y
43	depends on X86_32
44	depends on FUNCTION_TRACER
45	select DYNAMIC_FTRACE
46	help
47	  We keep the static function tracing (!DYNAMIC_FTRACE) around
48	  in order to test the non static function tracing in the
49	  generic code, as other architectures still use it. But we
50	  only need to keep it around for x86_64. No need to keep it
51	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
52#
53# Arch settings
54#
55# ( Note that options that are marked 'if X86_64' could in principle be
56#   ported to 32-bit as well. )
57#
58config X86
59	def_bool y
60	#
61	# Note: keep this list sorted alphabetically
62	#
63	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
64	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
65	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
66	select ARCH_32BIT_OFF_T			if X86_32
67	select ARCH_CLOCKSOURCE_INIT
68	select ARCH_CONFIGURES_CPU_MITIGATIONS
69	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
70	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
71	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
72	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
73	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
74	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
75	select ARCH_HAS_CPU_ATTACK_VECTORS	if CPU_MITIGATIONS
76	select ARCH_HAS_CACHE_LINE_SIZE
77	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
78	select ARCH_HAS_CPU_FINALIZE_INIT
79	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
80	select ARCH_HAS_CURRENT_STACK_POINTER
81	select ARCH_HAS_DEBUG_VIRTUAL
82	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
83	select ARCH_HAS_DEVMEM_IS_ALLOWED
84	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
85	select ARCH_HAS_EARLY_DEBUG		if KGDB
86	select ARCH_HAS_ELF_RANDOMIZE
87	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
88	select ARCH_HAS_FAST_MULTIPLIER
89	select ARCH_HAS_FORTIFY_SOURCE
90	select ARCH_HAS_GCOV_PROFILE_ALL
91	select ARCH_HAS_KCOV			if X86_64
92	select ARCH_HAS_KERNEL_FPU_SUPPORT
93	select ARCH_HAS_MEM_ENCRYPT
94	select ARCH_HAS_MEMBARRIER_SYNC_CORE
95	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
96	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
97	select ARCH_HAS_PMEM_API		if X86_64
98	select ARCH_HAS_PREEMPT_LAZY
99	select ARCH_HAS_PTDUMP
100	select ARCH_HAS_PTE_SPECIAL
101	select ARCH_HAS_HW_PTE_YOUNG
102	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
103	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
104	select ARCH_HAS_COPY_MC			if X86_64
105	select ARCH_HAS_SET_MEMORY
106	select ARCH_HAS_SET_DIRECT_MAP
107	select ARCH_HAS_STRICT_KERNEL_RWX
108	select ARCH_HAS_STRICT_MODULE_RWX
109	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
110	select ARCH_HAS_SYSCALL_WRAPPER
111	select ARCH_HAS_UBSAN
112	select ARCH_HAS_DEBUG_WX
113	select ARCH_HAS_ZONE_DMA_SET if EXPERT
114	select ARCH_HAVE_NMI_SAFE_CMPXCHG
115	select ARCH_HAVE_EXTRA_ELF_NOTES
116	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
117	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
118	select ARCH_MIGHT_HAVE_PC_PARPORT
119	select ARCH_MIGHT_HAVE_PC_SERIO
120	select ARCH_STACKWALK
121	select ARCH_SUPPORTS_ACPI
122	select ARCH_SUPPORTS_ATOMIC_RMW
123	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
124	select ARCH_SUPPORTS_HUGETLBFS
125	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
126	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
127	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
128	select ARCH_SUPPORTS_CFI		if X86_64
129	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI
130	select ARCH_SUPPORTS_LTO_CLANG
131	select ARCH_SUPPORTS_LTO_CLANG_THIN
132	select ARCH_SUPPORTS_RT
133	select ARCH_SUPPORTS_AUTOFDO_CLANG
134	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
135	select ARCH_USE_BUILTIN_BSWAP
136	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CX8
137	select ARCH_USE_MEMTEST
138	select ARCH_USE_QUEUED_RWLOCKS
139	select ARCH_USE_QUEUED_SPINLOCKS
140	select ARCH_USE_SYM_ANNOTATIONS
141	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
142	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
143	select ARCH_WANTS_CLOCKSOURCE_READ_INLINE	if X86_64
144	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
145	select ARCH_WANTS_NO_INSTR
146	select ARCH_WANT_GENERAL_HUGETLB
147	select ARCH_WANT_HUGE_PMD_SHARE		if X86_64
148	select ARCH_WANT_LD_ORPHAN_WARN
149	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
150	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
151	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
152	select ARCH_WANTS_THP_SWAP		if X86_64
153	select ARCH_HAS_PARANOID_L1D_FLUSH
154	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
155	select BUILDTIME_TABLE_SORT
156	select CLKEVT_I8253
157	select CLOCKSOURCE_WATCHDOG
158	# Word-size accesses may read uninitialized data past the trailing \0
159	# in strings and cause false KMSAN reports.
160	select DCACHE_WORD_ACCESS		if !KMSAN
161	select DYNAMIC_SIGFRAME
162	select EDAC_ATOMIC_SCRUB
163	select EDAC_SUPPORT
164	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
165	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
166	select GENERIC_CLOCKEVENTS_COUPLED_INLINE	if X86_64
167	select GENERIC_CLOCKEVENTS_MIN_ADJUST
168	select GENERIC_CMOS_UPDATE
169	select GENERIC_CPU_AUTOPROBE
170	select GENERIC_CPU_DEVICES
171	select GENERIC_CPU_VULNERABILITIES
172	select GENERIC_EARLY_IOREMAP
173	select GENERIC_ENTRY
174	select GENERIC_IOMAP
175	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
176	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
177	select GENERIC_IRQ_MIGRATION		if SMP
178	select GENERIC_IRQ_PROBE
179	select GENERIC_IRQ_RESERVATION_MODE
180	select GENERIC_IRQ_SHOW
181	select GENERIC_PENDING_IRQ		if SMP
182	select GENERIC_SMP_IDLE_THREAD
183	select GENERIC_TIME_VSYSCALL
184	select GENERIC_GETTIMEOFDAY
185	select GENERIC_VDSO_OVERFLOW_PROTECT
186	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
187	select HARDIRQS_SW_RESEND
188	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
189	select HAS_IOPORT
190	select HAVE_ACPI_APEI			if ACPI
191	select HAVE_ACPI_APEI_NMI		if ACPI
192	select HAVE_ALIGNED_STRUCT_PAGE
193	select HAVE_ARCH_AUDITSYSCALL
194	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
195	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
196	select HAVE_ARCH_JUMP_LABEL
197	select HAVE_ARCH_JUMP_LABEL_RELATIVE
198	select HAVE_ARCH_KASAN			if X86_64
199	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
200	select HAVE_ARCH_KFENCE
201	select HAVE_ARCH_KMSAN			if X86_64
202	select HAVE_ARCH_KGDB
203	select HAVE_ARCH_KSTACK_ERASE
204	select HAVE_ARCH_MMAP_RND_BITS		if MMU
205	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
206	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
207	select HAVE_ARCH_PREL32_RELOCATIONS
208	select HAVE_ARCH_SECCOMP_FILTER
209	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
210	select HAVE_ARCH_TRACEHOOK
211	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
212	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
213	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
214	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
215	select HAVE_ARCH_VMAP_STACK		if X86_64
216	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
217	select HAVE_ARCH_WITHIN_STACK_FRAMES
218	select HAVE_ASM_MODVERSIONS
219	select HAVE_CMPXCHG_DOUBLE
220	select HAVE_CMPXCHG_LOCAL
221	select HAVE_CONTEXT_TRACKING_USER		if X86_64
222	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
223	select HAVE_C_RECORDMCOUNT
224	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
225	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
226	select HAVE_BUILDTIME_MCOUNT_SORT
227	select HAVE_DEBUG_KMEMLEAK
228	select HAVE_DMA_CONTIGUOUS
229	select HAVE_DYNAMIC_FTRACE
230	select HAVE_DYNAMIC_FTRACE_WITH_REGS
231	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
232	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
233	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
234	select HAVE_DYNAMIC_FTRACE_WITH_JMP	if X86_64
235	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
236	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
237	select HAVE_EBPF_JIT
238	select HAVE_EFFICIENT_UNALIGNED_ACCESS
239	select HAVE_EISA			if X86_32
240	select HAVE_EXIT_THREAD
241	select HAVE_GENERIC_TIF_BITS
242	select HAVE_GUP_FAST
243	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
244	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
245	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
246	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
247	select HAVE_FUNCTION_TRACER
248	select HAVE_GCC_PLUGINS
249	select HAVE_HW_BREAKPOINT
250	select HAVE_IOREMAP_PROT
251	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
252	select HAVE_IRQ_TIME_ACCOUNTING
253	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
254	select HAVE_KERNEL_BZIP2
255	select HAVE_KERNEL_GZIP
256	select HAVE_KERNEL_LZ4
257	select HAVE_KERNEL_LZMA
258	select HAVE_KERNEL_LZO
259	select HAVE_KERNEL_XZ
260	select HAVE_KERNEL_ZSTD
261	select HAVE_KPROBES
262	select HAVE_KPROBES_ON_FTRACE
263	select HAVE_FUNCTION_ERROR_INJECTION
264	select HAVE_KRETPROBES
265	select HAVE_RETHOOK
266	select HAVE_KLP_BUILD			if X86_64
267	select HAVE_LIVEPATCH			if X86_64
268	select HAVE_MIXED_BREAKPOINTS_REGS
269	select HAVE_MOD_ARCH_SPECIFIC
270	select HAVE_MOVE_PMD
271	select HAVE_MOVE_PUD
272	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
273	select HAVE_NMI
274	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
275	select HAVE_OBJTOOL			if X86_64
276	select HAVE_OPTPROBES
277	select HAVE_PAGE_SIZE_4KB
278	select HAVE_PCSPKR_PLATFORM
279	select HAVE_PERF_EVENTS
280	select HAVE_PERF_EVENTS_NMI
281	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
282	select HAVE_PCI
283	select HAVE_PERF_REGS
284	select HAVE_PERF_USER_STACK_DUMP
285	select ASYNC_KERNEL_PGTABLE_FREE	if IOMMU_SVA
286	select MMU_GATHER_RCU_TABLE_FREE
287	select MMU_GATHER_MERGE_VMAS
288	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
289	select HAVE_REGS_AND_STACK_ACCESS_API
290	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
291	select HAVE_FUNCTION_ARG_ACCESS_API
292	select HAVE_SETUP_PER_CPU_AREA
293	select HAVE_SOFTIRQ_ON_OWN_STACK
294	select HAVE_STACKPROTECTOR
295	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
296	select HAVE_STATIC_CALL
297	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
298	select HAVE_PREEMPT_DYNAMIC_CALL
299	select HAVE_RSEQ
300	select HAVE_RUST			if X86_64
301	select HAVE_SYSCALL_TRACEPOINTS
302	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
303	select HAVE_UNSTABLE_SCHED_CLOCK
304	select HAVE_UNWIND_USER_FP		if X86_64
305	select HAVE_USER_RETURN_NOTIFIER
306	select HAVE_GENERIC_VDSO
307	select VDSO_GETRANDOM			if X86_64
308	select HOTPLUG_PARALLEL			if SMP && X86_64
309	select HOTPLUG_SMT			if SMP
310	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
311	select IRQ_FORCED_THREADING
312	select LOCK_MM_AND_FIND_VMA
313	select NEED_PER_CPU_EMBED_FIRST_CHUNK
314	select NEED_PER_CPU_PAGE_FIRST_CHUNK
315	select NEED_SG_DMA_LENGTH
316	select NUMA_MEMBLKS			if NUMA
317	select PCI_DOMAINS			if PCI
318	select PCI_LOCKLESS_CONFIG		if PCI
319	select PERF_EVENTS
320	select RTC_LIB
321	select RTC_MC146818_LIB
322	select SPARSE_IRQ
323	select SYSCTL_EXCEPTION_TRACE
324	select THREAD_INFO_IN_TASK
325	select TRACE_IRQFLAGS_SUPPORT
326	select TRACE_IRQFLAGS_NMI_SUPPORT
327	select USER_STACKTRACE_SUPPORT
328	select HAVE_ARCH_KCSAN			if X86_64
329	select PROC_PID_ARCH_STATUS		if PROC_FS
330	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
331	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
332	select FUNCTION_ALIGNMENT_4B
333	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
334	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
335	select ARCH_SUPPORTS_SCHED_SMT		if SMP
336	select SCHED_SMT			if SMP
337	select ARCH_SUPPORTS_SCHED_CLUSTER	if SMP
338	select ARCH_SUPPORTS_SCHED_MC		if SMP
339	select HAVE_SINGLE_FTRACE_DIRECT_OPS	if X86_64 && DYNAMIC_FTRACE_WITH_DIRECT_CALLS
340
341config INSTRUCTION_DECODER
342	def_bool y
343	depends on KPROBES || PERF_EVENTS || UPROBES
344
345config OUTPUT_FORMAT
346	string
347	default "elf32-i386" if X86_32
348	default "elf64-x86-64" if X86_64
349
350config LOCKDEP_SUPPORT
351	def_bool y
352
353config STACKTRACE_SUPPORT
354	def_bool y
355
356config MMU
357	def_bool y
358
359config ARCH_MMAP_RND_BITS_MIN
360	default 28 if 64BIT
361	default 8
362
363config ARCH_MMAP_RND_BITS_MAX
364	default 32 if 64BIT
365	default 16
366
367config ARCH_MMAP_RND_COMPAT_BITS_MIN
368	default 8
369
370config ARCH_MMAP_RND_COMPAT_BITS_MAX
371	default 16
372
373config SBUS
374	bool
375
376config GENERIC_ISA_DMA
377	def_bool y
378	depends on ISA_DMA_API
379
380config GENERIC_CSUM
381	bool
382	default y if KMSAN || KASAN
383
384config GENERIC_BUG
385	def_bool y
386	depends on BUG
387	select GENERIC_BUG_RELATIVE_POINTERS
388
389config GENERIC_BUG_RELATIVE_POINTERS
390	bool
391
392config ARCH_MAY_HAVE_PC_FDC
393	def_bool y
394	depends on ISA_DMA_API
395
396config GENERIC_CALIBRATE_DELAY
397	def_bool y
398
399config ARCH_HAS_CPU_RELAX
400	def_bool y
401
402config ARCH_HIBERNATION_POSSIBLE
403	def_bool y
404
405config ARCH_SUSPEND_POSSIBLE
406	def_bool y
407
408config AUDIT_ARCH
409	def_bool y if X86_64
410
411config KASAN_SHADOW_OFFSET
412	hex
413	depends on KASAN
414	default 0xdffffc0000000000
415
416config HAVE_INTEL_TXT
417	def_bool y
418	depends on INTEL_IOMMU && ACPI
419
420config ARCH_SUPPORTS_UPROBES
421	def_bool y
422
423config FIX_EARLYCON_MEM
424	def_bool y
425
426config DYNAMIC_PHYSICAL_MASK
427	bool
428
429config PGTABLE_LEVELS
430	int
431	default 5 if X86_64
432	default 3 if X86_PAE
433	default 2
434
435menu "Processor type and features"
436
437config SMP
438	bool "Symmetric multi-processing support"
439	help
440	  This enables support for systems with more than one CPU. If you have
441	  a system with only one CPU, say N. If you have a system with more
442	  than one CPU, say Y.
443
444	  If you say N here, the kernel will run on uni- and multiprocessor
445	  machines, but will use only one CPU of a multiprocessor machine. If
446	  you say Y here, the kernel will run on many, but not all,
447	  uniprocessor machines. On a uniprocessor machine, the kernel
448	  will run faster if you say N here.
449
450	  People using multiprocessor machines who say Y here should also say
451	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
452	  Management" code will be disabled if you say Y here.
453
454	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
455	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
456	  <http://www.tldp.org/docs.html#howto>.
457
458	  If you don't know what to do here, say N.
459
460config X86_X2APIC
461	bool "x2APIC interrupt controller architecture support"
462	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
463	default y
464	help
465	  x2APIC is an interrupt controller architecture, a component of which
466	  (the local APIC) is present in the CPU. It allows faster access to
467	  the local APIC and supports a larger number of CPUs in the system
468	  than the predecessors.
469
470	  x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs
471	  in 2019, but it can be disabled by the BIOS. It is also frequently
472	  emulated in virtual machines, even when the host CPU does not support
473	  it. Support in the CPU can be checked by executing
474		grep x2apic /proc/cpuinfo
475
476	  If this configuration option is disabled, the kernel will boot with
477	  very reduced functionality and performance on some platforms that
478	  have x2APIC enabled. On the other hand, on hardware that does not
479	  support x2APIC, a kernel with this option enabled will just fallback
480	  to older APIC implementations.
481
482	  If in doubt, say Y.
483
484config AMD_SECURE_AVIC
485	bool "AMD Secure AVIC"
486	depends on AMD_MEM_ENCRYPT && X86_X2APIC
487	help
488	  Enable this to get AMD Secure AVIC support on guests that have this feature.
489
490	  AMD Secure AVIC provides hardware acceleration for performance sensitive
491	  APIC accesses and support for managing guest owned APIC state for SEV-SNP
492	  guests. Secure AVIC does not support xAPIC mode. It has functional
493	  dependency on x2apic being enabled in the guest.
494
495	  If you don't know what to do here, say N.
496
497config X86_POSTED_MSI
498	bool "Enable MSI and MSI-x delivery by posted interrupts"
499	depends on X86_64 && IRQ_REMAP
500	help
501	  This enables MSIs that are under interrupt remapping to be delivered as
502	  posted interrupts to the host kernel. Interrupt throughput can
503	  potentially be improved by coalescing CPU notifications during high
504	  frequency bursts.
505
506	  If you don't know what to do here, say N.
507
508config X86_MPPARSE
509	bool "Enable MPS table" if ACPI
510	default y
511	depends on X86_LOCAL_APIC
512	help
513	  For old smp systems that do not have proper acpi support. Newer systems
514	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
515
516config X86_CPU_RESCTRL
517	bool "x86 CPU resource control support"
518	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
519	depends on MISC_FILESYSTEMS
520	select ARCH_HAS_CPU_RESCTRL
521	select RESCTRL_FS
522	select RESCTRL_FS_PSEUDO_LOCK
523	help
524	  Enable x86 CPU resource control support.
525
526	  Provide support for the allocation and monitoring of system resources
527	  usage by the CPU.
528
529	  Intel calls this Intel Resource Director Technology
530	  (Intel(R) RDT). More information about RDT can be found in the
531	  Intel x86 Architecture Software Developer Manual.
532
533	  AMD calls this AMD Platform Quality of Service (AMD QoS).
534	  More information about AMD QoS can be found in the AMD64 Technology
535	  Platform Quality of Service Extensions manual.
536
537	  Say N if unsure.
538
539config X86_CPU_RESCTRL_INTEL_AET
540	bool "Intel Application Energy Telemetry"
541	depends on X86_64 && X86_CPU_RESCTRL && CPU_SUP_INTEL && INTEL_PMT_TELEMETRY=y && INTEL_TPMI=y
542	help
543	  Enable per-RMID telemetry events in resctrl.
544
545	  Intel feature that collects per-RMID execution data
546	  about energy consumption, measure of frequency independent
547	  activity and other performance metrics. Data is aggregated
548	  per package.
549
550	  Say N if unsure.
551
552config X86_FRED
553	bool "Flexible Return and Event Delivery"
554	depends on X86_64
555	help
556	  When enabled, use Flexible Return and Event Delivery
557	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
558	  ring transitions and exception/interrupt handling if the
559	  system supports it.
560
561config X86_EXTENDED_PLATFORM
562	bool "Support for extended (non-PC) x86 platforms"
563	default y
564	help
565	  If you disable this option then the kernel will only support
566	  standard PC platforms. (which covers the vast majority of
567	  systems out there.)
568
569	  If you enable this option then you'll be able to select support
570	  for the following non-PC x86 platforms, depending on the value of
571	  CONFIG_64BIT.
572
573	  32-bit platforms (CONFIG_64BIT=n):
574		Goldfish (mostly Android emulator)
575		Intel CE media processor (CE4100) SoC
576		Intel Quark
577		RDC R-321x SoC
578
579	  64-bit platforms (CONFIG_64BIT=y):
580		Numascale NumaChip
581		ScaleMP vSMP
582		SGI Ultraviolet
583		Merrifield/Moorefield MID devices
584		Goldfish (mostly Android emulator)
585
586	  If you have one of these systems, or if you want to build a
587	  generic distribution kernel, say Y here - otherwise say N.
588
589# This is an alphabetically sorted list of 64 bit extended platforms
590# Please maintain the alphabetic order if and when there are additions
591config X86_NUMACHIP
592	bool "Numascale NumaChip"
593	depends on X86_64
594	depends on X86_EXTENDED_PLATFORM
595	depends on NUMA
596	depends on SMP
597	depends on X86_X2APIC
598	depends on PCI_MMCONFIG
599	help
600	  Adds support for Numascale NumaChip large-SMP systems. Needed to
601	  enable more than ~168 cores.
602	  If you don't have one of these, you should say N here.
603
604config X86_VSMP
605	bool "ScaleMP vSMP"
606	select HYPERVISOR_GUEST
607	select PARAVIRT
608	depends on X86_64 && PCI
609	depends on X86_EXTENDED_PLATFORM
610	depends on SMP
611	help
612	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
613	  supposed to run on these EM64T-based machines.  Only choose this option
614	  if you have one of these machines.
615
616config X86_UV
617	bool "SGI Ultraviolet"
618	depends on X86_64
619	depends on X86_EXTENDED_PLATFORM
620	depends on NUMA
621	depends on EFI
622	depends on KEXEC_CORE
623	depends on X86_X2APIC
624	depends on PCI
625	help
626	  This option is needed in order to support SGI Ultraviolet systems.
627	  If you don't have one of these, you should say N here.
628
629config X86_INTEL_MID
630	bool "Intel Z34xx/Z35xx MID platform support"
631	depends on X86_EXTENDED_PLATFORM
632	depends on X86_PLATFORM_DEVICES
633	depends on PCI
634	depends on X86_64 || (EXPERT && PCI_GOANY)
635	depends on X86_IO_APIC
636	select I2C
637	select DW_APB_TIMER
638	select INTEL_SCU_PCI
639	help
640	  Select to build a kernel capable of supporting 64-bit Intel MID
641	  (Mobile Internet Device) platform systems which do not have
642	  the PCI legacy interfaces.
643
644	  The only supported devices are the 22nm Merrified (Z34xx)
645	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
646	  a small number of Android devices such as the Asus Zenfone 2,
647	  Asus FonePad 8 and Dell Venue 7.
648
649	  If you are building for a PC class system or non-MID tablet
650	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
651
652	  Intel MID platforms are based on an Intel processor and chipset which
653	  consume less power than most of the x86 derivatives.
654
655config X86_GOLDFISH
656	bool "Goldfish (Virtual Platform)"
657	depends on X86_EXTENDED_PLATFORM
658	help
659	  Enable support for the Goldfish virtual platform used primarily
660	  for Android development. Unless you are building for the Android
661	  Goldfish emulator say N here.
662
663# Following is an alphabetically sorted list of 32 bit extended platforms
664# Please maintain the alphabetic order if and when there are additions
665
666config X86_INTEL_CE
667	bool "CE4100 TV platform"
668	depends on PCI
669	depends on PCI_GODIRECT
670	depends on X86_IO_APIC
671	depends on X86_32
672	depends on X86_EXTENDED_PLATFORM
673	select X86_REBOOTFIXUPS
674	select OF
675	select OF_EARLY_FLATTREE
676	help
677	  Select for the Intel CE media processor (CE4100) SOC.
678	  This option compiles in support for the CE4100 SOC for settop
679	  boxes and media devices.
680
681config X86_INTEL_QUARK
682	bool "Intel Quark platform support"
683	depends on X86_32
684	depends on X86_EXTENDED_PLATFORM
685	depends on X86_PLATFORM_DEVICES
686	depends on X86_TSC
687	depends on PCI
688	depends on PCI_GOANY
689	depends on X86_IO_APIC
690	select IOSF_MBI
691	select INTEL_IMR
692	select COMMON_CLK
693	help
694	  Select to include support for Quark X1000 SoC.
695	  Say Y here if you have a Quark based system such as the Arduino
696	  compatible Intel Galileo.
697
698config X86_INTEL_LPSS
699	bool "Intel Low Power Subsystem Support"
700	depends on X86 && ACPI && PCI
701	select COMMON_CLK
702	select PINCTRL
703	select IOSF_MBI
704	help
705	  Select to build support for Intel Low Power Subsystem such as
706	  found on Intel Lynxpoint PCH. Selecting this option enables
707	  things like clock tree (common clock framework) and pincontrol
708	  which are needed by the LPSS peripheral drivers.
709
710config X86_AMD_PLATFORM_DEVICE
711	bool "AMD ACPI2Platform devices support"
712	depends on ACPI
713	select COMMON_CLK
714	select PINCTRL
715	help
716	  Select to interpret AMD specific ACPI device to platform device
717	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
718	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
719	  implemented under PINCTRL subsystem.
720
721config IOSF_MBI
722	tristate "Intel SoC IOSF Sideband support for SoC platforms"
723	depends on PCI
724	help
725	  This option enables sideband register access support for Intel SoC
726	  platforms. On these platforms the IOSF sideband is used in lieu of
727	  MSR's for some register accesses, mostly but not limited to thermal
728	  and power. Drivers may query the availability of this device to
729	  determine if they need the sideband in order to work on these
730	  platforms. The sideband is available on the following SoC products.
731	  This list is not meant to be exclusive.
732	   - BayTrail
733	   - Braswell
734	   - Quark
735
736	  You should say Y if you are running a kernel on one of these SoC's.
737
738config IOSF_MBI_DEBUG
739	bool "Enable IOSF sideband access through debugfs"
740	depends on IOSF_MBI && DEBUG_FS
741	help
742	  Select this option to expose the IOSF sideband access registers (MCR,
743	  MDR, MCRX) through debugfs to write and read register information from
744	  different units on the SoC. This is most useful for obtaining device
745	  state information for debug and analysis. As this is a general access
746	  mechanism, users of this option would have specific knowledge of the
747	  device they want to access.
748
749	  If you don't require the option or are in doubt, say N.
750
751config X86_SUPPORTS_MEMORY_FAILURE
752	def_bool y
753	# MCE code calls memory_failure():
754	depends on X86_MCE
755	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
756	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
757	depends on X86_64 || !SPARSEMEM
758	select ARCH_SUPPORTS_MEMORY_FAILURE
759
760config X86_32_IRIS
761	tristate "Eurobraille/Iris poweroff module"
762	depends on X86_32
763	help
764	  The Iris machines from EuroBraille do not have APM or ACPI support
765	  to shut themselves down properly.  A special I/O sequence is
766	  needed to do so, which is what this module does at
767	  kernel shutdown.
768
769	  This is only for Iris machines from EuroBraille.
770
771	  If unused, say N.
772
773config SCHED_OMIT_FRAME_POINTER
774	def_bool y
775	prompt "Single-depth WCHAN output"
776	depends on X86
777	help
778	  Calculate simpler /proc/<PID>/wchan values. If this option
779	  is disabled then wchan values will recurse back to the
780	  caller function. This provides more accurate wchan values,
781	  at the expense of slightly more scheduling overhead.
782
783	  If in doubt, say "Y".
784
785menuconfig HYPERVISOR_GUEST
786	bool "Linux guest support"
787	help
788	  Say Y here to enable options for running Linux under various hyper-
789	  visors. This option enables basic hypervisor detection and platform
790	  setup.
791
792	  If you say N, all options in this submenu will be skipped and
793	  disabled, and Linux guest support won't be built in.
794
795if HYPERVISOR_GUEST
796
797config PARAVIRT
798	bool "Enable paravirtualization code"
799	depends on HAVE_STATIC_CALL
800	select HAVE_PV_STEAL_CLOCK_GEN
801	help
802	  This changes the kernel so it can modify itself when it is run
803	  under a hypervisor, potentially improving performance significantly
804	  over full virtualization.  However, when run without a hypervisor
805	  the kernel is theoretically slower and slightly larger.
806
807config PARAVIRT_XXL
808	bool
809	depends on X86_64
810	select ARCH_HAS_LAZY_MMU_MODE
811
812config PARAVIRT_SPINLOCKS
813	bool "Paravirtualization layer for spinlocks"
814	depends on PARAVIRT && SMP
815	help
816	  Paravirtualized spinlocks allow a pvops backend to replace the
817	  spinlock implementation with something virtualization-friendly
818	  (for example, block the virtual CPU rather than spinning).
819
820	  It has a minimal impact on native kernels and gives a nice performance
821	  benefit on paravirtualized KVM / Xen kernels.
822
823	  If you are unsure how to answer this question, answer Y.
824
825config X86_HV_CALLBACK_VECTOR
826	def_bool n
827
828source "arch/x86/xen/Kconfig"
829
830config KVM_GUEST
831	bool "KVM Guest support (including kvmclock)"
832	depends on PARAVIRT
833	select PARAVIRT_CLOCK
834	select ARCH_CPUIDLE_HALTPOLL
835	select X86_HV_CALLBACK_VECTOR
836	default y
837	help
838	  This option enables various optimizations for running under the KVM
839	  hypervisor. It includes a paravirtualized clock, so that instead
840	  of relying on a PIT (or probably other) emulation by the
841	  underlying device model, the host provides the guest with
842	  timing infrastructure such as time of day, and system time
843
844config ARCH_CPUIDLE_HALTPOLL
845	def_bool n
846	prompt "Disable host haltpoll when loading haltpoll driver"
847	help
848	  If virtualized under KVM, disable host haltpoll.
849
850config PVH
851	bool "Support for running PVH guests"
852	help
853	  This option enables the PVH entry point for guest virtual machines
854	  as specified in the x86/HVM direct boot ABI.
855
856config PARAVIRT_TIME_ACCOUNTING
857	bool "Paravirtual steal time accounting"
858	depends on PARAVIRT
859	help
860	  Select this option to enable fine granularity task steal time
861	  accounting. Time spent executing other tasks in parallel with
862	  the current vCPU is discounted from the vCPU power. To account for
863	  that, there can be a small performance impact.
864
865	  If in doubt, say N here.
866
867config PARAVIRT_CLOCK
868	bool
869
870config JAILHOUSE_GUEST
871	bool "Jailhouse non-root cell support"
872	depends on X86_64 && PCI
873	select X86_PM_TIMER
874	help
875	  This option allows to run Linux as guest in a Jailhouse non-root
876	  cell. You can leave this option disabled if you only want to start
877	  Jailhouse and run Linux afterwards in the root cell.
878
879config ACRN_GUEST
880	bool "ACRN Guest support"
881	depends on X86_64
882	select X86_HV_CALLBACK_VECTOR
883	help
884	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
885	  a flexible, lightweight reference open-source hypervisor, built with
886	  real-time and safety-criticality in mind. It is built for embedded
887	  IOT with small footprint and real-time features. More details can be
888	  found in https://projectacrn.org/.
889
890config BHYVE_GUEST
891	bool "Bhyve (BSD Hypervisor) Guest support"
892	depends on X86_64
893	help
894	  This option allows to run Linux to recognise when it is running as a
895	  guest in the Bhyve hypervisor, and to support more than 255 vCPUs when
896	  when doing so. More details about Bhyve can be found at https://bhyve.org
897	  and https://wiki.freebsd.org/bhyve/.
898
899config INTEL_TDX_GUEST
900	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
901	depends on X86_64 && CPU_SUP_INTEL
902	depends on X86_X2APIC
903	depends on EFI_STUB
904	depends on PARAVIRT
905	select ARCH_HAS_CC_PLATFORM
906	select X86_MEM_ENCRYPT
907	select X86_MCE
908	select UNACCEPTED_MEMORY
909	help
910	  Support running as a guest under Intel TDX.  Without this support,
911	  the guest kernel can not boot or run under TDX.
912	  TDX includes memory encryption and integrity capabilities
913	  which protect the confidentiality and integrity of guest
914	  memory contents and CPU state. TDX guests are protected from
915	  some attacks from the VMM.
916
917endif # HYPERVISOR_GUEST
918
919source "arch/x86/Kconfig.cpu"
920
921config HPET_TIMER
922	def_bool X86_64
923	prompt "HPET Timer Support" if X86_32
924	help
925	  Use the IA-PC HPET (High Precision Event Timer) to manage
926	  time in preference to the PIT and RTC, if a HPET is
927	  present.
928	  HPET is the next generation timer replacing legacy 8254s.
929	  The HPET provides a stable time base on SMP
930	  systems, unlike the TSC, but it is more expensive to access,
931	  as it is off-chip.  The interface used is documented
932	  in the HPET spec, revision 1.
933
934	  You can safely choose Y here.  However, HPET will only be
935	  activated if the platform and the BIOS support this feature.
936	  Otherwise the 8254 will be used for timing services.
937
938	  Choose N to continue using the legacy 8254 timer.
939
940config HPET_EMULATE_RTC
941	def_bool y
942	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
943
944# Mark as expert because too many people got it wrong.
945# The code disables itself when not needed.
946config DMI
947	default y
948	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
949	bool "Enable DMI scanning" if EXPERT
950	help
951	  Enabled scanning of DMI to identify machine quirks. Say Y
952	  here unless you have verified that your setup is not
953	  affected by entries in the DMI blacklist. Required by PNP
954	  BIOS code.
955
956config GART_IOMMU
957	bool "Old AMD GART IOMMU support"
958	select IOMMU_HELPER
959	select SWIOTLB
960	depends on X86_64 && PCI && AMD_NB
961	help
962	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
963	  GART based hardware IOMMUs.
964
965	  The GART supports full DMA access for devices with 32-bit access
966	  limitations, on systems with more than 3 GB. This is usually needed
967	  for USB, sound, many IDE/SATA chipsets and some other devices.
968
969	  Newer systems typically have a modern AMD IOMMU, supported via
970	  the CONFIG_AMD_IOMMU=y config option.
971
972	  In normal configurations this driver is only active when needed:
973	  there's more than 3 GB of memory and the system contains a
974	  32-bit limited device.
975
976	  If unsure, say Y.
977
978config BOOT_VESA_SUPPORT
979	bool
980	help
981	  If true, at least one selected framebuffer driver can take advantage
982	  of VESA video modes set at an early boot stage via the vga= parameter.
983
984config MAXSMP
985	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
986	depends on X86_64 && SMP && DEBUG_KERNEL
987	select CPUMASK_OFFSTACK
988	help
989	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
990	  If unsure, say N.
991
992#
993# The maximum number of CPUs supported:
994#
995# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
996# and which can be configured interactively in the
997# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
998#
999# The ranges are different on 32-bit and 64-bit kernels, depending on
1000# hardware capabilities and scalability features of the kernel.
1001#
1002# ( If MAXSMP is enabled we just use the highest possible value and disable
1003#   interactive configuration. )
1004#
1005
1006config NR_CPUS_RANGE_BEGIN
1007	int
1008	default NR_CPUS_RANGE_END if MAXSMP
1009	default    1 if !SMP
1010	default    2
1011
1012config NR_CPUS_RANGE_END
1013	int
1014	depends on X86_32
1015	default    8 if  SMP
1016	default    1 if !SMP
1017
1018config NR_CPUS_RANGE_END
1019	int
1020	depends on X86_64
1021	default 8192 if  SMP && CPUMASK_OFFSTACK
1022	default  512 if  SMP && !CPUMASK_OFFSTACK
1023	default    1 if !SMP
1024
1025config NR_CPUS_DEFAULT
1026	int
1027	depends on X86_32
1028	default    8 if  SMP
1029	default    1 if !SMP
1030
1031config NR_CPUS_DEFAULT
1032	int
1033	depends on X86_64
1034	default 8192 if  MAXSMP
1035	default   64 if  SMP
1036	default    1 if !SMP
1037
1038config NR_CPUS
1039	int "Maximum number of CPUs" if SMP && !MAXSMP
1040	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1041	default NR_CPUS_DEFAULT
1042	help
1043	  This allows you to specify the maximum number of CPUs which this
1044	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1045	  supported value is 8192, otherwise the maximum value is 512.  The
1046	  minimum value which makes sense is 2.
1047
1048	  This is purely to save memory: each supported CPU adds about 8KB
1049	  to the kernel image.
1050
1051config SCHED_MC_PRIO
1052	bool "CPU core priorities scheduler support"
1053	depends on SCHED_MC
1054	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1055	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1056	select CPU_FREQ
1057	default y
1058	help
1059	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1060	  core ordering determined at manufacturing time, which allows
1061	  certain cores to reach higher turbo frequencies (when running
1062	  single threaded workloads) than others.
1063
1064	  Enabling this kernel feature teaches the scheduler about
1065	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1066	  scheduler's CPU selection logic accordingly, so that higher
1067	  overall system performance can be achieved.
1068
1069	  This feature will have no effect on CPUs without this feature.
1070
1071	  If unsure say Y here.
1072
1073config UP_LATE_INIT
1074	def_bool y
1075	depends on !SMP && X86_LOCAL_APIC
1076
1077config X86_UP_APIC
1078	bool "Local APIC support on uniprocessors" if !PCI_MSI
1079	default PCI_MSI
1080	depends on X86_32 && !SMP
1081	help
1082	  A local APIC (Advanced Programmable Interrupt Controller) is an
1083	  integrated interrupt controller in the CPU. If you have a single-CPU
1084	  system which has a processor with a local APIC, you can say Y here to
1085	  enable and use it. If you say Y here even though your machine doesn't
1086	  have a local APIC, then the kernel will still run with no slowdown at
1087	  all. The local APIC supports CPU-generated self-interrupts (timer,
1088	  performance counters), and the NMI watchdog which detects hard
1089	  lockups.
1090
1091config X86_UP_IOAPIC
1092	bool "IO-APIC support on uniprocessors"
1093	depends on X86_UP_APIC
1094	help
1095	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1096	  SMP-capable replacement for PC-style interrupt controllers. Most
1097	  SMP systems and many recent uniprocessor systems have one.
1098
1099	  If you have a single-CPU system with an IO-APIC, you can say Y here
1100	  to use it. If you say Y here even though your machine doesn't have
1101	  an IO-APIC, then the kernel will still run with no slowdown at all.
1102
1103config X86_LOCAL_APIC
1104	def_bool y
1105	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1106	select IRQ_DOMAIN_HIERARCHY
1107
1108config ACPI_MADT_WAKEUP
1109	def_bool y
1110	depends on X86_64
1111	depends on ACPI
1112	depends on SMP
1113	depends on X86_LOCAL_APIC
1114
1115config X86_IO_APIC
1116	def_bool y
1117	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1118
1119config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1120	bool "Reroute for broken boot IRQs"
1121	depends on X86_IO_APIC
1122	help
1123	  This option enables a workaround that fixes a source of
1124	  spurious interrupts. This is recommended when threaded
1125	  interrupt handling is used on systems where the generation of
1126	  superfluous "boot interrupts" cannot be disabled.
1127
1128	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1129	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1130	  kernel does during interrupt handling). On chipsets where this
1131	  boot IRQ generation cannot be disabled, this workaround keeps
1132	  the original IRQ line masked so that only the equivalent "boot
1133	  IRQ" is delivered to the CPUs. The workaround also tells the
1134	  kernel to set up the IRQ handler on the boot IRQ line. In this
1135	  way only one interrupt is delivered to the kernel. Otherwise
1136	  the spurious second interrupt may cause the kernel to bring
1137	  down (vital) interrupt lines.
1138
1139	  Only affects "broken" chipsets. Interrupt sharing may be
1140	  increased on these systems.
1141
1142config X86_MCE
1143	bool "Machine Check / overheating reporting"
1144	select GENERIC_ALLOCATOR
1145	default y
1146	help
1147	  Machine Check support allows the processor to notify the
1148	  kernel if it detects a problem (e.g. overheating, data corruption).
1149	  The action the kernel takes depends on the severity of the problem,
1150	  ranging from warning messages to halting the machine.
1151
1152config X86_MCELOG_LEGACY
1153	bool "Support for deprecated /dev/mcelog character device"
1154	depends on X86_MCE
1155	help
1156	  Enable support for /dev/mcelog which is needed by the old mcelog
1157	  userspace logging daemon. Consider switching to the new generation
1158	  rasdaemon solution.
1159
1160config X86_MCE_INTEL
1161	def_bool y
1162	prompt "Intel MCE features"
1163	depends on X86_MCE && X86_LOCAL_APIC
1164	help
1165	  Additional support for intel specific MCE features such as
1166	  the thermal monitor.
1167
1168config X86_MCE_AMD
1169	def_bool y
1170	prompt "AMD MCE features"
1171	depends on X86_MCE && X86_LOCAL_APIC
1172	help
1173	  Additional support for AMD specific MCE features such as
1174	  the DRAM Error Threshold.
1175
1176config X86_ANCIENT_MCE
1177	bool "Support for old Pentium 5 / WinChip machine checks"
1178	depends on X86_32 && X86_MCE
1179	help
1180	  Include support for machine check handling on old Pentium 5 or WinChip
1181	  systems. These typically need to be enabled explicitly on the command
1182	  line.
1183
1184config X86_MCE_THRESHOLD
1185	depends on X86_MCE_AMD || X86_MCE_INTEL
1186	def_bool y
1187
1188config X86_MCE_INJECT
1189	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1190	tristate "Machine check injector support"
1191	help
1192	  Provide support for injecting machine checks for testing purposes.
1193	  If you don't know what a machine check is and you don't do kernel
1194	  QA it is safe to say n.
1195
1196source "arch/x86/events/Kconfig"
1197
1198config X86_LEGACY_VM86
1199	bool "Legacy VM86 support"
1200	depends on X86_32
1201	help
1202	  This option allows user programs to put the CPU into V8086
1203	  mode, which is an 80286-era approximation of 16-bit real mode.
1204
1205	  Some very old versions of X and/or vbetool require this option
1206	  for user mode setting.  Similarly, DOSEMU will use it if
1207	  available to accelerate real mode DOS programs.  However, any
1208	  recent version of DOSEMU, X, or vbetool should be fully
1209	  functional even without kernel VM86 support, as they will all
1210	  fall back to software emulation. Nevertheless, if you are using
1211	  a 16-bit DOS program where 16-bit performance matters, vm86
1212	  mode might be faster than emulation and you might want to
1213	  enable this option.
1214
1215	  Note that any app that works on a 64-bit kernel is unlikely to
1216	  need this option, as 64-bit kernels don't, and can't, support
1217	  V8086 mode. This option is also unrelated to 16-bit protected
1218	  mode and is not needed to run most 16-bit programs under Wine.
1219
1220	  Enabling this option increases the complexity of the kernel
1221	  and slows down exception handling a tiny bit.
1222
1223	  If unsure, say N here.
1224
1225config VM86
1226	bool
1227	default X86_LEGACY_VM86
1228
1229config X86_16BIT
1230	bool "Enable support for 16-bit segments" if EXPERT
1231	default y
1232	depends on MODIFY_LDT_SYSCALL
1233	help
1234	  This option is required by programs like Wine to run 16-bit
1235	  protected mode legacy code on x86 processors.  Disabling
1236	  this option saves about 300 bytes on i386, or around 6K text
1237	  plus 16K runtime memory on x86-64,
1238
1239config X86_ESPFIX32
1240	def_bool y
1241	depends on X86_16BIT && X86_32
1242
1243config X86_ESPFIX64
1244	def_bool y
1245	depends on X86_16BIT && X86_64
1246
1247config X86_VSYSCALL_EMULATION
1248	bool "Enable vsyscall emulation" if EXPERT
1249	default y
1250	depends on X86_64
1251	help
1252	  This enables emulation of the legacy vsyscall page.  Disabling
1253	  it is roughly equivalent to booting with vsyscall=none, except
1254	  that it will also disable the helpful warning if a program
1255	  tries to use a vsyscall.  With this option set to N, offending
1256	  programs will just segfault, citing addresses of the form
1257	  0xffffffffff600?00.
1258
1259	  This option is required by many programs built before 2013, and
1260	  care should be used even with newer programs if set to N.
1261
1262	  Disabling this option saves about 7K of kernel size and
1263	  possibly 4K of additional runtime pagetable memory.
1264
1265config X86_IOPL_IOPERM
1266	bool "IOPERM and IOPL Emulation"
1267	default y
1268	help
1269	  This enables the ioperm() and iopl() syscalls which are necessary
1270	  for legacy applications.
1271
1272	  Legacy IOPL support is an overbroad mechanism which allows user
1273	  space aside of accessing all 65536 I/O ports also to disable
1274	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1275	  capabilities and permission from potentially active security
1276	  modules.
1277
1278	  The emulation restricts the functionality of the syscall to
1279	  only allowing the full range I/O port access, but prevents the
1280	  ability to disable interrupts from user space which would be
1281	  granted if the hardware IOPL mechanism would be used.
1282
1283config TOSHIBA
1284	tristate "Toshiba Laptop support"
1285	depends on X86_32
1286	help
1287	  This adds a driver to safely access the System Management Mode of
1288	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1289	  not work on models with a Phoenix BIOS. The System Management Mode
1290	  is used to set the BIOS and power saving options on Toshiba portables.
1291
1292	  For information on utilities to make use of this driver see the
1293	  Toshiba Linux utilities web site at:
1294	  <http://www.buzzard.org.uk/toshiba/>.
1295
1296	  Say Y if you intend to run this kernel on a Toshiba portable.
1297	  Say N otherwise.
1298
1299config X86_REBOOTFIXUPS
1300	bool "Enable X86 board specific fixups for reboot"
1301	depends on X86_32
1302	help
1303	  This enables chipset and/or board specific fixups to be done
1304	  in order to get reboot to work correctly. This is only needed on
1305	  some combinations of hardware and BIOS. The symptom, for which
1306	  this config is intended, is when reboot ends with a stalled/hung
1307	  system.
1308
1309	  Currently, the only fixup is for the Geode machines using
1310	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1311
1312	  Say Y if you want to enable the fixup. Currently, it's safe to
1313	  enable this option even if you don't need it.
1314	  Say N otherwise.
1315
1316config MICROCODE
1317	def_bool y
1318	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1319	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1320
1321config MICROCODE_INITRD32
1322	def_bool y
1323	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1324
1325config MICROCODE_LATE_LOADING
1326	bool "Late microcode loading (DANGEROUS)"
1327	default n
1328	depends on MICROCODE && SMP
1329	help
1330	  Loading microcode late, when the system is up and executing instructions
1331	  is a tricky business and should be avoided if possible. Just the sequence
1332	  of synchronizing all cores and SMT threads is one fragile dance which does
1333	  not guarantee that cores might not softlock after the loading. Therefore,
1334	  use this at your own risk. Late loading taints the kernel unless the
1335	  microcode header indicates that it is safe for late loading via the
1336	  minimal revision check. This minimal revision check can be enforced on
1337	  the kernel command line with "microcode=force_minrev".
1338
1339config MICROCODE_LATE_FORCE_MINREV
1340	bool "Enforce late microcode loading minimal revision check"
1341	default n
1342	depends on MICROCODE_LATE_LOADING
1343	help
1344	  To prevent that users load microcode late which modifies already
1345	  in use features, newer microcode patches have a minimum revision field
1346	  in the microcode header, which tells the kernel which minimum
1347	  revision must be active in the CPU to safely load that new microcode
1348	  late into the running system. If disabled the check will not
1349	  be enforced but the kernel will be tainted when the minimal
1350	  revision check fails.
1351
1352	  This minimal revision check can also be controlled via the
1353	  "microcode=force_minrev" parameter on the kernel command line.
1354
1355	  If unsure say Y.
1356
1357config MICROCODE_DBG
1358	bool "Enable microcode loader debugging"
1359	default n
1360	depends on MICROCODE
1361	help
1362	  Enable code which allows to debug the microcode loader. When running
1363	  in a guest the patch loading is simulated but everything else
1364	  related to patch parsing and handling is done as on baremetal with
1365	  the purpose of debugging solely the software side of things. On
1366	  baremetal, it simply dumps additional debugging information during
1367	  normal operation.
1368
1369	  You almost certainly want to say n here.
1370
1371config X86_MSR
1372	tristate "/dev/cpu/*/msr - Model-specific register support"
1373	help
1374	  This device gives privileged processes access to the x86
1375	  Model-Specific Registers (MSRs).  It is a character device with
1376	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1377	  MSR accesses are directed to a specific CPU on multi-processor
1378	  systems.
1379
1380config X86_CPUID
1381	tristate "/dev/cpu/*/cpuid - CPU information support"
1382	help
1383	  This device gives processes access to the x86 CPUID instruction to
1384	  be executed on a specific processor.  It is a character device
1385	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1386	  /dev/cpu/31/cpuid.
1387
1388config HIGHMEM4G
1389	bool "High Memory Support"
1390	depends on X86_32
1391	help
1392	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1393	  However, the address space of 32-bit x86 processors is only 4
1394	  Gigabytes large. That means that, if you have a large amount of
1395	  physical memory, not all of it can be "permanently mapped" by the
1396	  kernel. The physical memory that's not permanently mapped is called
1397	  "high memory".
1398
1399	  If you are compiling a kernel which will never run on a machine with
1400	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1401	  choice and suitable for most users). This will result in a "3GB/1GB"
1402	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1403	  space and the remaining part of the 4GB virtual memory space is used
1404	  by the kernel to permanently map as much physical memory as
1405	  possible.
1406
1407	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1408	  answer "Y" here.
1409
1410	  If unsure, say N.
1411
1412choice
1413	prompt "Memory split" if EXPERT
1414	default VMSPLIT_3G
1415	depends on X86_32
1416	help
1417	  Select the desired split between kernel and user memory.
1418
1419	  If the address range available to the kernel is less than the
1420	  physical memory installed, the remaining memory will be available
1421	  as "high memory". Accessing high memory is a little more costly
1422	  than low memory, as it needs to be mapped into the kernel first.
1423	  Note that increasing the kernel address space limits the range
1424	  available to user programs, making the address space there
1425	  tighter.  Selecting anything other than the default 3G/1G split
1426	  will also likely make your kernel incompatible with binary-only
1427	  kernel modules.
1428
1429	  If you are not absolutely sure what you are doing, leave this
1430	  option alone!
1431
1432	config VMSPLIT_3G
1433		bool "3G/1G user/kernel split"
1434	config VMSPLIT_3G_OPT
1435		depends on !X86_PAE
1436		bool "3G/1G user/kernel split (for full 1G low memory)"
1437	config VMSPLIT_2G
1438		bool "2G/2G user/kernel split"
1439	config VMSPLIT_2G_OPT
1440		depends on !X86_PAE
1441		bool "2G/2G user/kernel split (for full 2G low memory)"
1442	config VMSPLIT_1G
1443		bool "1G/3G user/kernel split"
1444endchoice
1445
1446config PAGE_OFFSET
1447	hex
1448	default 0xB0000000 if VMSPLIT_3G_OPT
1449	default 0x80000000 if VMSPLIT_2G
1450	default 0x78000000 if VMSPLIT_2G_OPT
1451	default 0x40000000 if VMSPLIT_1G
1452	default 0xC0000000
1453	depends on X86_32
1454
1455config HIGHMEM
1456	def_bool HIGHMEM4G
1457
1458config X86_PAE
1459	bool "PAE (Physical Address Extension) Support"
1460	depends on X86_32 && X86_HAVE_PAE
1461	select PHYS_ADDR_T_64BIT
1462	help
1463	  PAE is required for NX support, and furthermore enables
1464	  larger swapspace support for non-overcommit purposes. It
1465	  has the cost of more pagetable lookup overhead, and also
1466	  consumes more pagetable space per process.
1467
1468config X86_DIRECT_GBPAGES
1469	def_bool y
1470	depends on X86_64
1471	help
1472	  Certain kernel features effectively disable kernel
1473	  linear 1 GB mappings (even if the CPU otherwise
1474	  supports them), so don't confuse the user by printing
1475	  that we have them enabled.
1476
1477config X86_CPA_STATISTICS
1478	bool "Enable statistic for Change Page Attribute"
1479	depends on DEBUG_FS
1480	help
1481	  Expose statistics about the Change Page Attribute mechanism, which
1482	  helps to determine the effectiveness of preserving large and huge
1483	  page mappings when mapping protections are changed.
1484
1485config X86_MEM_ENCRYPT
1486	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1487	select DYNAMIC_PHYSICAL_MASK
1488	def_bool n
1489
1490config AMD_MEM_ENCRYPT
1491	bool "AMD Secure Memory Encryption (SME) support"
1492	depends on X86_64 && CPU_SUP_AMD
1493	depends on EFI_STUB
1494	select DMA_COHERENT_POOL
1495	select ARCH_USE_MEMREMAP_PROT
1496	select INSTRUCTION_DECODER
1497	select ARCH_HAS_CC_PLATFORM
1498	select X86_MEM_ENCRYPT
1499	select UNACCEPTED_MEMORY
1500	select CRYPTO_LIB_AESGCM
1501	help
1502	  Say yes to enable support for the encryption of system memory.
1503	  This requires an AMD processor that supports Secure Memory
1504	  Encryption (SME).
1505
1506# Common NUMA Features
1507config NUMA
1508	bool "NUMA Memory Allocation and Scheduler Support"
1509	depends on SMP
1510	depends on X86_64
1511	select USE_PERCPU_NUMA_NODE_ID
1512	select OF_NUMA if OF
1513	help
1514	  Enable NUMA (Non-Uniform Memory Access) support.
1515
1516	  The kernel will try to allocate memory used by a CPU on the
1517	  local memory controller of the CPU and add some more
1518	  NUMA awareness to the kernel.
1519
1520	  For 64-bit this is recommended if the system is Intel Core i7
1521	  (or later), AMD Opteron, or EM64T NUMA.
1522
1523	  Otherwise, you should say N.
1524
1525config AMD_NUMA
1526	def_bool y
1527	prompt "Old style AMD Opteron NUMA detection"
1528	depends on X86_64 && NUMA && PCI
1529	help
1530	  Enable AMD NUMA node topology detection.  You should say Y here if
1531	  you have a multi processor AMD system. This uses an old method to
1532	  read the NUMA configuration directly from the builtin Northbridge
1533	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1534	  which also takes priority if both are compiled in.
1535
1536config X86_64_ACPI_NUMA
1537	def_bool y
1538	prompt "ACPI NUMA detection"
1539	depends on X86_64 && NUMA && ACPI && PCI
1540	select ACPI_NUMA
1541	help
1542	  Enable ACPI SRAT based node topology detection.
1543
1544config NODES_SHIFT
1545	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1546	range 1 10
1547	default "10" if MAXSMP
1548	default "6" if X86_64
1549	default "3"
1550	depends on NUMA
1551	help
1552	  Specify the maximum number of NUMA Nodes available on the target
1553	  system.  Increases memory reserved to accommodate various tables.
1554
1555config ARCH_FLATMEM_ENABLE
1556	def_bool y
1557	depends on X86_32 && !NUMA
1558
1559config ARCH_SPARSEMEM_ENABLE
1560	def_bool y
1561	select SPARSEMEM_STATIC if X86_32
1562	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1563
1564config ARCH_SPARSEMEM_DEFAULT
1565	def_bool X86_64 || (NUMA && X86_32)
1566
1567config ARCH_SELECT_MEMORY_MODEL
1568	def_bool y
1569	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1570
1571config ARCH_MEMORY_PROBE
1572	bool "Enable sysfs memory/probe interface"
1573	depends on MEMORY_HOTPLUG
1574	help
1575	  This option enables a sysfs memory/probe interface for testing.
1576	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1577	  If you are unsure how to answer this question, answer N.
1578
1579config ARCH_PROC_KCORE_TEXT
1580	def_bool y
1581	depends on X86_64 && PROC_KCORE
1582
1583config ILLEGAL_POINTER_VALUE
1584	hex
1585	default 0 if X86_32
1586	default 0xdead000000000000 if X86_64
1587
1588config X86_PMEM_LEGACY_DEVICE
1589	bool
1590
1591config X86_PMEM_LEGACY
1592	tristate "Support non-standard NVDIMMs and ADR protected memory"
1593	depends on PHYS_ADDR_T_64BIT
1594	depends on BLK_DEV
1595	select X86_PMEM_LEGACY_DEVICE
1596	select NUMA_KEEP_MEMINFO if NUMA
1597	select LIBNVDIMM
1598	help
1599	  Treat memory marked using the non-standard e820 type of 12 as used
1600	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1601	  The kernel will offer these regions to the 'pmem' driver so
1602	  they can be used for persistent storage.
1603
1604	  Say Y if unsure.
1605
1606config X86_CHECK_BIOS_CORRUPTION
1607	bool "Check for low memory corruption"
1608	help
1609	  Periodically check for memory corruption in low memory, which
1610	  is suspected to be caused by BIOS.  Even when enabled in the
1611	  configuration, it is disabled at runtime.  Enable it by
1612	  setting "memory_corruption_check=1" on the kernel command
1613	  line.  By default it scans the low 64k of memory every 60
1614	  seconds; see the memory_corruption_check_size and
1615	  memory_corruption_check_period parameters in
1616	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1617
1618	  When enabled with the default parameters, this option has
1619	  almost no overhead, as it reserves a relatively small amount
1620	  of memory and scans it infrequently.  It both detects corruption
1621	  and prevents it from affecting the running system.
1622
1623	  It is, however, intended as a diagnostic tool; if repeatable
1624	  BIOS-originated corruption always affects the same memory,
1625	  you can use memmap= to prevent the kernel from using that
1626	  memory.
1627
1628config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1629	bool "Set the default setting of memory_corruption_check"
1630	depends on X86_CHECK_BIOS_CORRUPTION
1631	default y
1632	help
1633	  Set whether the default state of memory_corruption_check is
1634	  on or off.
1635
1636config MATH_EMULATION
1637	bool
1638	depends on MODIFY_LDT_SYSCALL
1639	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1640	help
1641	  Linux can emulate a math coprocessor (used for floating point
1642	  operations) if you don't have one. 486DX and Pentium processors have
1643	  a math coprocessor built in, 486SX and 386 do not, unless you added
1644	  a 487DX or 387, respectively. (The messages during boot time can
1645	  give you some hints here ["man dmesg"].) Everyone needs either a
1646	  coprocessor or this emulation.
1647
1648	  If you don't have a math coprocessor, you need to say Y here; if you
1649	  say Y here even though you have a coprocessor, the coprocessor will
1650	  be used nevertheless. (This behavior can be changed with the kernel
1651	  command line option "no387", which comes handy if your coprocessor
1652	  is broken. Try "man bootparam" or see the documentation of your boot
1653	  loader (lilo or loadlin) about how to pass options to the kernel at
1654	  boot time.) This means that it is a good idea to say Y here if you
1655	  intend to use this kernel on different machines.
1656
1657	  More information about the internals of the Linux math coprocessor
1658	  emulation can be found in <file:arch/x86/math-emu/README>.
1659
1660	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1661	  kernel, it won't hurt.
1662
1663config MTRR
1664	def_bool y
1665	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1666	help
1667	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1668	  the Memory Type Range Registers (MTRRs) may be used to control
1669	  processor access to memory ranges. This is most useful if you have
1670	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1671	  allows bus write transfers to be combined into a larger transfer
1672	  before bursting over the PCI/AGP bus. This can increase performance
1673	  of image write operations 2.5 times or more. Saying Y here creates a
1674	  /proc/mtrr file which may be used to manipulate your processor's
1675	  MTRRs. Typically the X server should use this.
1676
1677	  This code has a reasonably generic interface so that similar
1678	  control registers on other processors can be easily supported
1679	  as well:
1680
1681	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1682	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1683	  these, the ARRs are used to emulate the MTRRs.
1684	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1685	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1686	  write-combining. All of these processors are supported by this code
1687	  and it makes sense to say Y here if you have one of them.
1688
1689	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1690	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1691	  can lead to all sorts of problems, so it's good to say Y here.
1692
1693	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1694	  just add about 9 KB to your kernel.
1695
1696	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1697
1698config MTRR_SANITIZER
1699	def_bool y
1700	prompt "MTRR cleanup support"
1701	depends on MTRR
1702	help
1703	  Convert MTRR layout from continuous to discrete, so X drivers can
1704	  add writeback entries.
1705
1706	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1707	  The largest mtrr entry size for a continuous block can be set with
1708	  mtrr_chunk_size.
1709
1710	  If unsure, say Y.
1711
1712config MTRR_SANITIZER_ENABLE_DEFAULT
1713	int "MTRR cleanup enable value (0-1)"
1714	range 0 1
1715	default "0"
1716	depends on MTRR_SANITIZER
1717	help
1718	  Enable mtrr cleanup default value
1719
1720config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1721	int "MTRR cleanup spare reg num (0-7)"
1722	range 0 7
1723	default "1"
1724	depends on MTRR_SANITIZER
1725	help
1726	  mtrr cleanup spare entries default, it can be changed via
1727	  mtrr_spare_reg_nr=N on the kernel command line.
1728
1729config X86_PAT
1730	def_bool y
1731	prompt "x86 PAT support" if EXPERT
1732	depends on MTRR
1733	select ARCH_USES_PG_ARCH_2
1734	help
1735	  Use PAT attributes to setup page level cache control.
1736
1737	  PATs are the modern equivalents of MTRRs and are much more
1738	  flexible than MTRRs.
1739
1740	  Say N here if you see bootup problems (boot crash, boot hang,
1741	  spontaneous reboots) or a non-working video driver.
1742
1743	  If unsure, say Y.
1744
1745config X86_UMIP
1746	def_bool y
1747	prompt "User Mode Instruction Prevention" if EXPERT
1748	help
1749	  User Mode Instruction Prevention (UMIP) is a security feature in
1750	  some x86 processors. If enabled, a general protection fault is
1751	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1752	  executed in user mode. These instructions unnecessarily expose
1753	  information about the hardware state.
1754
1755	  The vast majority of applications do not use these instructions.
1756	  For the very few that do, software emulation is provided in
1757	  specific cases in protected and virtual-8086 modes. Emulated
1758	  results are dummy.
1759
1760config CC_HAS_IBT
1761	# GCC >= 9 and binutils >= 2.29
1762	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1763	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || CC_IS_CLANG) && \
1764		  $(as-instr,endbr64)
1765
1766config X86_CET
1767	def_bool n
1768	help
1769	  CET features configured (Shadow stack or IBT)
1770
1771config X86_KERNEL_IBT
1772	prompt "Indirect Branch Tracking"
1773	def_bool y
1774	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1775	select OBJTOOL
1776	select X86_CET
1777	help
1778	  Build the kernel with support for Indirect Branch Tracking, a
1779	  hardware support course-grain forward-edge Control Flow Integrity
1780	  protection. It enforces that all indirect calls must land on
1781	  an ENDBR instruction, as such, the compiler will instrument the
1782	  code with them to make this happen.
1783
1784	  In addition to building the kernel with IBT, seal all functions that
1785	  are not indirect call targets, avoiding them ever becoming one.
1786
1787	  This requires LTO like objtool runs and will slow down the build. It
1788	  does significantly reduce the number of ENDBR instructions in the
1789	  kernel image.
1790
1791config X86_INTEL_MEMORY_PROTECTION_KEYS
1792	prompt "Memory Protection Keys"
1793	def_bool y
1794	# Note: only available in 64-bit mode
1795	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1796	select ARCH_USES_HIGH_VMA_FLAGS
1797	select ARCH_HAS_PKEYS
1798	help
1799	  Memory Protection Keys provides a mechanism for enforcing
1800	  page-based protections, but without requiring modification of the
1801	  page tables when an application changes protection domains.
1802
1803	  For details, see Documentation/core-api/protection-keys.rst
1804
1805	  If unsure, say y.
1806
1807config ARCH_PKEY_BITS
1808	int
1809	default 4
1810
1811choice
1812	prompt "TSX enable mode"
1813	depends on CPU_SUP_INTEL
1814	default X86_INTEL_TSX_MODE_AUTO
1815	help
1816	  Intel's TSX (Transactional Synchronization Extensions) feature
1817	  allows to optimize locking protocols through lock elision which
1818	  can lead to a noticeable performance boost.
1819
1820	  On the other hand it has been shown that TSX can be exploited
1821	  to form side channel attacks (e.g. TAA) and chances are there
1822	  will be more of those attacks discovered in the future.
1823
1824	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1825	  might override this decision by tsx=on the command line parameter.
1826	  Even with TSX enabled, the kernel will attempt to enable the best
1827	  possible TAA mitigation setting depending on the microcode available
1828	  for the particular machine.
1829
1830	  This option allows to set the default tsx mode between tsx=on, =off
1831	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1832	  details.
1833
1834	  Say off if not sure, auto if TSX is in use but it should be used on safe
1835	  platforms or on if TSX is in use and the security aspect of tsx is not
1836	  relevant.
1837
1838config X86_INTEL_TSX_MODE_OFF
1839	bool "off"
1840	help
1841	  TSX is disabled if possible - equals to tsx=off command line parameter.
1842
1843config X86_INTEL_TSX_MODE_ON
1844	bool "on"
1845	help
1846	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1847	  line parameter.
1848
1849config X86_INTEL_TSX_MODE_AUTO
1850	bool "auto"
1851	help
1852	  TSX is enabled on TSX capable HW that is believed to be safe against
1853	  side channel attacks- equals the tsx=auto command line parameter.
1854endchoice
1855
1856config X86_SGX
1857	bool "Software Guard eXtensions (SGX)"
1858	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1859	select CRYPTO_LIB_SHA256
1860	select MMU_NOTIFIER
1861	select NUMA_KEEP_MEMINFO if NUMA
1862	select XARRAY_MULTI
1863	help
1864	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1865	  that can be used by applications to set aside private regions of code
1866	  and data, referred to as enclaves. An enclave's private memory can
1867	  only be accessed by code running within the enclave. Accesses from
1868	  outside the enclave, including other enclaves, are disallowed by
1869	  hardware.
1870
1871	  If unsure, say N.
1872
1873config X86_USER_SHADOW_STACK
1874	bool "X86 userspace shadow stack"
1875	depends on AS_WRUSS
1876	depends on X86_64
1877	depends on PER_VMA_LOCK
1878	select ARCH_USES_HIGH_VMA_FLAGS
1879	select ARCH_HAS_USER_SHADOW_STACK
1880	select X86_CET
1881	help
1882	  Shadow stack protection is a hardware feature that detects function
1883	  return address corruption.  This helps mitigate ROP attacks.
1884	  Applications must be enabled to use it, and old userspace does not
1885	  get protection "for free".
1886
1887	  CPUs supporting shadow stacks were first released in 2020.
1888
1889	  See Documentation/arch/x86/shstk.rst for more information.
1890
1891	  If unsure, say N.
1892
1893config INTEL_TDX_HOST
1894	bool "Intel Trust Domain Extensions (TDX) host support"
1895	depends on CPU_SUP_INTEL
1896	depends on X86_64
1897	depends on KVM_INTEL
1898	depends on X86_X2APIC
1899	select ARCH_KEEP_MEMBLOCK
1900	depends on CONTIG_ALLOC
1901	depends on X86_MCE
1902	help
1903	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1904	  host and certain physical attacks.  This option enables necessary TDX
1905	  support in the host kernel to run confidential VMs.
1906
1907	  If unsure, say N.
1908
1909config EFI
1910	bool "EFI runtime service support"
1911	depends on ACPI
1912	select UCS2_STRING
1913	select EFI_RUNTIME_WRAPPERS
1914	select ARCH_USE_MEMREMAP_PROT
1915	select EFI_RUNTIME_MAP if KEXEC_CORE
1916	help
1917	  This enables the kernel to use EFI runtime services that are
1918	  available (such as the EFI variable services).
1919
1920	  This option is only useful on systems that have EFI firmware.
1921	  In addition, you should use the latest ELILO loader available
1922	  at <http://elilo.sourceforge.net> in order to take advantage
1923	  of EFI runtime services. However, even with this option, the
1924	  resultant kernel should continue to boot on existing non-EFI
1925	  platforms.
1926
1927config EFI_STUB
1928	bool "EFI stub support"
1929	depends on EFI
1930	select RELOCATABLE
1931	help
1932	  This kernel feature allows a bzImage to be loaded directly
1933	  by EFI firmware without the use of a bootloader.
1934
1935	  See Documentation/admin-guide/efi-stub.rst for more information.
1936
1937config EFI_HANDOVER_PROTOCOL
1938	bool "EFI handover protocol (DEPRECATED)"
1939	depends on EFI_STUB
1940	default y
1941	help
1942	  Select this in order to include support for the deprecated EFI
1943	  handover protocol, which defines alternative entry points into the
1944	  EFI stub.  This is a practice that has no basis in the UEFI
1945	  specification, and requires a priori knowledge on the part of the
1946	  bootloader about Linux/x86 specific ways of passing the command line
1947	  and initrd, and where in memory those assets may be loaded.
1948
1949	  If in doubt, say Y. Even though the corresponding support is not
1950	  present in upstream GRUB or other bootloaders, most distros build
1951	  GRUB with numerous downstream patches applied, and may rely on the
1952	  handover protocol as as result.
1953
1954config EFI_MIXED
1955	bool "EFI mixed-mode support"
1956	depends on EFI_STUB && X86_64
1957	help
1958	  Enabling this feature allows a 64-bit kernel to be booted
1959	  on a 32-bit firmware, provided that your CPU supports 64-bit
1960	  mode.
1961
1962	  Note that it is not possible to boot a mixed-mode enabled
1963	  kernel via the EFI boot stub - a bootloader that supports
1964	  the EFI handover protocol must be used.
1965
1966	  If unsure, say N.
1967
1968config EFI_RUNTIME_MAP
1969	bool "Export EFI runtime maps to sysfs" if EXPERT
1970	depends on EFI
1971	help
1972	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1973	  That memory map is required by the 2nd kernel to set up EFI virtual
1974	  mappings after kexec, but can also be used for debugging purposes.
1975
1976	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1977
1978source "kernel/Kconfig.hz"
1979
1980config ARCH_SUPPORTS_KEXEC
1981	def_bool y
1982
1983config ARCH_SUPPORTS_KEXEC_FILE
1984	def_bool X86_64
1985
1986config ARCH_SELECTS_KEXEC_FILE
1987	def_bool y
1988	depends on KEXEC_FILE
1989	select HAVE_IMA_KEXEC if IMA
1990
1991config ARCH_SUPPORTS_KEXEC_PURGATORY
1992	def_bool y
1993
1994config ARCH_SUPPORTS_KEXEC_SIG
1995	def_bool y
1996
1997config ARCH_SUPPORTS_KEXEC_SIG_FORCE
1998	def_bool y
1999
2000config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2001	def_bool y
2002
2003config ARCH_SUPPORTS_KEXEC_JUMP
2004	def_bool y
2005
2006config ARCH_SUPPORTS_KEXEC_HANDOVER
2007	def_bool X86_64
2008
2009config ARCH_SUPPORTS_CRASH_DUMP
2010	def_bool X86_64 || (X86_32 && HIGHMEM)
2011
2012config ARCH_DEFAULT_CRASH_DUMP
2013	def_bool y
2014
2015config ARCH_SUPPORTS_CRASH_HOTPLUG
2016	def_bool y
2017
2018config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2019	def_bool CRASH_RESERVE
2020
2021config PHYSICAL_START
2022	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2023	default "0x1000000"
2024	help
2025	  This gives the physical address where the kernel is loaded.
2026
2027	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2028	  will decompress itself to above physical address and run from there.
2029	  Otherwise, bzImage will run from the address where it has been loaded
2030	  by the boot loader. The only exception is if it is loaded below the
2031	  above physical address, in which case it will relocate itself there.
2032
2033	  In normal kdump cases one does not have to set/change this option
2034	  as now bzImage can be compiled as a completely relocatable image
2035	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2036	  address. This option is mainly useful for the folks who don't want
2037	  to use a bzImage for capturing the crash dump and want to use a
2038	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2039	  to be specifically compiled to run from a specific memory area
2040	  (normally a reserved region) and this option comes handy.
2041
2042	  So if you are using bzImage for capturing the crash dump,
2043	  leave the value here unchanged to 0x1000000 and set
2044	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2045	  for capturing the crash dump change this value to start of
2046	  the reserved region.  In other words, it can be set based on
2047	  the "X" value as specified in the "crashkernel=YM@XM"
2048	  command line boot parameter passed to the panic-ed
2049	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2050	  for more details about crash dumps.
2051
2052	  Usage of bzImage for capturing the crash dump is recommended as
2053	  one does not have to build two kernels. Same kernel can be used
2054	  as production kernel and capture kernel. Above option should have
2055	  gone away after relocatable bzImage support is introduced. But it
2056	  is present because there are users out there who continue to use
2057	  vmlinux for dump capture. This option should go away down the
2058	  line.
2059
2060	  Don't change this unless you know what you are doing.
2061
2062config RELOCATABLE
2063	bool "Build a relocatable kernel"
2064	default y
2065	help
2066	  This builds a kernel image that retains relocation information
2067	  so it can be loaded someplace besides the default 1MB.
2068	  The relocations tend to make the kernel binary about 10% larger,
2069	  but are discarded at runtime.
2070
2071	  One use is for the kexec on panic case where the recovery kernel
2072	  must live at a different physical address than the primary
2073	  kernel.
2074
2075	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2076	  it has been loaded at and the compile time physical address
2077	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2078
2079config RANDOMIZE_BASE
2080	bool "Randomize the address of the kernel image (KASLR)"
2081	depends on RELOCATABLE
2082	default y
2083	help
2084	  In support of Kernel Address Space Layout Randomization (KASLR),
2085	  this randomizes the physical address at which the kernel image
2086	  is decompressed and the virtual address where the kernel
2087	  image is mapped, as a security feature that deters exploit
2088	  attempts relying on knowledge of the location of kernel
2089	  code internals.
2090
2091	  On 64-bit, the kernel physical and virtual addresses are
2092	  randomized separately. The physical address will be anywhere
2093	  between 16MB and the top of physical memory (up to 64TB). The
2094	  virtual address will be randomized from 16MB up to 1GB (9 bits
2095	  of entropy). Note that this also reduces the memory space
2096	  available to kernel modules from 1.5GB to 1GB.
2097
2098	  On 32-bit, the kernel physical and virtual addresses are
2099	  randomized together. They will be randomized from 16MB up to
2100	  512MB (8 bits of entropy).
2101
2102	  Entropy is generated using the RDRAND instruction if it is
2103	  supported. If RDTSC is supported, its value is mixed into
2104	  the entropy pool as well. If neither RDRAND nor RDTSC are
2105	  supported, then entropy is read from the i8254 timer. The
2106	  usable entropy is limited by the kernel being built using
2107	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2108	  minimum of 2MB. As a result, only 10 bits of entropy are
2109	  theoretically possible, but the implementations are further
2110	  limited due to memory layouts.
2111
2112	  If unsure, say Y.
2113
2114# Relocation on x86 needs some additional build support
2115config X86_NEED_RELOCS
2116	def_bool y
2117	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2118	select ARCH_VMLINUX_NEEDS_RELOCS
2119
2120config PHYSICAL_ALIGN
2121	hex "Alignment value to which kernel should be aligned"
2122	default "0x200000"
2123	range 0x2000 0x1000000 if X86_32
2124	range 0x200000 0x1000000 if X86_64
2125	help
2126	  This value puts the alignment restrictions on physical address
2127	  where kernel is loaded and run from. Kernel is compiled for an
2128	  address which meets above alignment restriction.
2129
2130	  If bootloader loads the kernel at a non-aligned address and
2131	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2132	  address aligned to above value and run from there.
2133
2134	  If bootloader loads the kernel at a non-aligned address and
2135	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2136	  load address and decompress itself to the address it has been
2137	  compiled for and run from there. The address for which kernel is
2138	  compiled already meets above alignment restrictions. Hence the
2139	  end result is that kernel runs from a physical address meeting
2140	  above alignment restrictions.
2141
2142	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2143	  this value must be a multiple of 0x200000.
2144
2145	  Don't change this unless you know what you are doing.
2146
2147config RANDOMIZE_MEMORY
2148	bool "Randomize the kernel memory sections"
2149	depends on X86_64
2150	depends on RANDOMIZE_BASE
2151	default RANDOMIZE_BASE
2152	help
2153	  Randomizes the base virtual address of kernel memory sections
2154	  (physical memory mapping, vmalloc & vmemmap). This security feature
2155	  makes exploits relying on predictable memory locations less reliable.
2156
2157	  The order of allocations remains unchanged. Entropy is generated in
2158	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2159	  configuration have in average 30,000 different possible virtual
2160	  addresses for each memory section.
2161
2162	  If unsure, say Y.
2163
2164config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2165	hex "Physical memory mapping padding" if EXPERT
2166	depends on RANDOMIZE_MEMORY
2167	default "0xa" if MEMORY_HOTPLUG
2168	default "0x0"
2169	range 0x1 0x40 if MEMORY_HOTPLUG
2170	range 0x0 0x40
2171	help
2172	  Define the padding in terabytes added to the existing physical
2173	  memory size during kernel memory randomization. It is useful
2174	  for memory hotplug support but reduces the entropy available for
2175	  address randomization.
2176
2177	  If unsure, leave at the default value.
2178
2179config ADDRESS_MASKING
2180	bool "Linear Address Masking support"
2181	depends on X86_64
2182	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2183	help
2184	  Linear Address Masking (LAM) modifies the checking that is applied
2185	  to 64-bit linear addresses, allowing software to use of the
2186	  untranslated address bits for metadata.
2187
2188	  The capability can be used for efficient address sanitizers (ASAN)
2189	  implementation and for optimizations in JITs.
2190
2191config HOTPLUG_CPU
2192	def_bool y
2193	depends on SMP
2194
2195config COMPAT_VDSO
2196	def_bool n
2197	prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)"
2198	depends on COMPAT_32
2199	help
2200	  Certain buggy versions of glibc will crash if they are
2201	  presented with a 32-bit vDSO that is not mapped at the address
2202	  indicated in its segment table.
2203
2204	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2205	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2206	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2207	  the only released version with the bug, but OpenSUSE 9
2208	  contains a buggy "glibc 2.3.2".
2209
2210	  The symptom of the bug is that everything crashes on startup, saying:
2211	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2212
2213	  Saying Y here changes the default value of the vdso32 boot
2214	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2215	  This works around the glibc bug but hurts performance.
2216
2217	  If unsure, say N: if you are compiling your own kernel, you
2218	  are unlikely to be using a buggy version of glibc.
2219
2220choice
2221	prompt "vsyscall table for legacy applications"
2222	depends on X86_64
2223	default LEGACY_VSYSCALL_XONLY
2224	help
2225	  Legacy user code that does not know how to find the vDSO expects
2226	  to be able to issue three syscalls by calling fixed addresses in
2227	  kernel space. Since this location is not randomized with ASLR,
2228	  it can be used to assist security vulnerability exploitation.
2229
2230	  This setting can be changed at boot time via the kernel command
2231	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2232	  is deprecated and can only be enabled using the kernel command
2233	  line.
2234
2235	  On a system with recent enough glibc (2.14 or newer) and no
2236	  static binaries, you can say None without a performance penalty
2237	  to improve security.
2238
2239	  If unsure, select "Emulate execution only".
2240
2241	config LEGACY_VSYSCALL_XONLY
2242		bool "Emulate execution only"
2243		help
2244		  The kernel traps and emulates calls into the fixed vsyscall
2245		  address mapping and does not allow reads.  This
2246		  configuration is recommended when userspace might use the
2247		  legacy vsyscall area but support for legacy binary
2248		  instrumentation of legacy code is not needed.  It mitigates
2249		  certain uses of the vsyscall area as an ASLR-bypassing
2250		  buffer.
2251
2252	config LEGACY_VSYSCALL_NONE
2253		bool "None"
2254		help
2255		  There will be no vsyscall mapping at all. This will
2256		  eliminate any risk of ASLR bypass due to the vsyscall
2257		  fixed address mapping. Attempts to use the vsyscalls
2258		  will be reported to dmesg, so that either old or
2259		  malicious userspace programs can be identified.
2260
2261endchoice
2262
2263config CMDLINE_BOOL
2264	bool "Built-in kernel command line"
2265	help
2266	  Allow for specifying boot arguments to the kernel at
2267	  build time.  On some systems (e.g. embedded ones), it is
2268	  necessary or convenient to provide some or all of the
2269	  kernel boot arguments with the kernel itself (that is,
2270	  to not rely on the boot loader to provide them.)
2271
2272	  To compile command line arguments into the kernel,
2273	  set this option to 'Y', then fill in the
2274	  boot arguments in CONFIG_CMDLINE.
2275
2276	  Systems with fully functional boot loaders (i.e. non-embedded)
2277	  should leave this option set to 'N'.
2278
2279config CMDLINE
2280	string "Built-in kernel command string"
2281	depends on CMDLINE_BOOL
2282	default ""
2283	help
2284	  Enter arguments here that should be compiled into the kernel
2285	  image and used at boot time.  If the boot loader provides a
2286	  command line at boot time, it is appended to this string to
2287	  form the full kernel command line, when the system boots.
2288
2289	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2290	  change this behavior.
2291
2292	  In most cases, the command line (whether built-in or provided
2293	  by the boot loader) should specify the device for the root
2294	  file system.
2295
2296config CMDLINE_OVERRIDE
2297	bool "Built-in command line overrides boot loader arguments"
2298	depends on CMDLINE_BOOL && CMDLINE != ""
2299	help
2300	  Set this option to 'Y' to have the kernel ignore the boot loader
2301	  command line, and use ONLY the built-in command line.
2302
2303	  This is used to work around broken boot loaders.  This should
2304	  be set to 'N' under normal conditions.
2305
2306config MODIFY_LDT_SYSCALL
2307	bool "Enable the LDT (local descriptor table)" if EXPERT
2308	default y
2309	help
2310	  Linux can allow user programs to install a per-process x86
2311	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2312	  call.  This is required to run 16-bit or segmented code such as
2313	  DOSEMU or some Wine programs.  It is also used by some very old
2314	  threading libraries.
2315
2316	  Enabling this feature adds a small amount of overhead to
2317	  context switches and increases the low-level kernel attack
2318	  surface.  Disabling it removes the modify_ldt(2) system call.
2319
2320	  Saying 'N' here may make sense for embedded or server kernels.
2321
2322config STRICT_SIGALTSTACK_SIZE
2323	bool "Enforce strict size checking for sigaltstack"
2324	depends on DYNAMIC_SIGFRAME
2325	help
2326	  For historical reasons MINSIGSTKSZ is a constant which became
2327	  already too small with AVX512 support. Add a mechanism to
2328	  enforce strict checking of the sigaltstack size against the
2329	  real size of the FPU frame. This option enables the check
2330	  by default. It can also be controlled via the kernel command
2331	  line option 'strict_sas_size' independent of this config
2332	  switch. Enabling it might break existing applications which
2333	  allocate a too small sigaltstack but 'work' because they
2334	  never get a signal delivered.
2335
2336	  Say 'N' unless you want to really enforce this check.
2337
2338config CFI_AUTO_DEFAULT
2339	bool "Attempt to use FineIBT by default at boot time"
2340	depends on FINEIBT
2341	depends on !RUST || RUSTC_VERSION >= 108800
2342	default y
2343	help
2344	  Attempt to use FineIBT by default at boot time. If enabled,
2345	  this is the same as booting with "cfi=auto". If disabled,
2346	  this is the same as booting with "cfi=kcfi".
2347
2348source "kernel/livepatch/Kconfig"
2349
2350config X86_BUS_LOCK_DETECT
2351	bool "Split Lock Detect and Bus Lock Detect support"
2352	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2353	default y
2354	help
2355	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2356	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2357
2358endmenu
2359
2360config CC_HAS_NAMED_AS
2361	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2362	depends on CC_IS_GCC
2363
2364#
2365# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2366# are incompatible with named address spaces with GCC < 13.3
2367# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2368#
2369
2370config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2371	def_bool y
2372	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2373	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2374
2375config USE_X86_SEG_SUPPORT
2376	def_bool CC_HAS_NAMED_AS
2377	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2378
2379config CC_HAS_SLS
2380	def_bool $(cc-option,-mharden-sls=all)
2381
2382config CC_HAS_RETURN_THUNK
2383	def_bool $(cc-option,-mfunction-return=thunk-extern)
2384
2385config CC_HAS_ENTRY_PADDING
2386	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2387
2388config CC_HAS_KCFI_ARITY
2389	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2390	depends on CC_IS_CLANG && !RUST
2391
2392config FUNCTION_PADDING_CFI
2393	int
2394	default 59 if FUNCTION_ALIGNMENT_64B
2395	default 27 if FUNCTION_ALIGNMENT_32B
2396	default 11 if FUNCTION_ALIGNMENT_16B
2397	default  3 if FUNCTION_ALIGNMENT_8B
2398	default  0
2399
2400# Basically: FUNCTION_ALIGNMENT - 5*CFI
2401# except Kconfig can't do arithmetic :/
2402config FUNCTION_PADDING_BYTES
2403	int
2404	default FUNCTION_PADDING_CFI if CFI
2405	default FUNCTION_ALIGNMENT
2406
2407config CALL_PADDING
2408	def_bool n
2409	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2410	select FUNCTION_ALIGNMENT_16B
2411
2412config FINEIBT
2413	def_bool y
2414	depends on X86_KERNEL_IBT && CFI && MITIGATION_RETPOLINE
2415	select CALL_PADDING
2416
2417config FINEIBT_BHI
2418	def_bool y
2419	depends on FINEIBT && CC_HAS_KCFI_ARITY
2420
2421config HAVE_CALL_THUNKS
2422	def_bool y
2423	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2424
2425config CALL_THUNKS
2426	def_bool n
2427	select CALL_PADDING
2428
2429config PREFIX_SYMBOLS
2430	def_bool y
2431	depends on CALL_PADDING && !CFI
2432
2433menuconfig CPU_MITIGATIONS
2434	bool "Mitigations for CPU vulnerabilities"
2435	default y
2436	help
2437	  Say Y here to enable options which enable mitigations for hardware
2438	  vulnerabilities (usually related to speculative execution).
2439	  Mitigations can be disabled or restricted to SMT systems at runtime
2440	  via the "mitigations" kernel parameter.
2441
2442	  If you say N, all mitigations will be disabled.  This CANNOT be
2443	  overridden at runtime.
2444
2445	  Say 'Y', unless you really know what you are doing.
2446
2447if CPU_MITIGATIONS
2448
2449config MITIGATION_PAGE_TABLE_ISOLATION
2450	bool "Remove the kernel mapping in user mode"
2451	default y
2452	depends on (X86_64 || X86_PAE)
2453	help
2454	  This feature reduces the number of hardware side channels by
2455	  ensuring that the majority of kernel addresses are not mapped
2456	  into userspace.
2457
2458	  See Documentation/arch/x86/pti.rst for more details.
2459
2460config MITIGATION_RETPOLINE
2461	bool "Avoid speculative indirect branches in kernel"
2462	select OBJTOOL if HAVE_OBJTOOL
2463	default y
2464	help
2465	  Compile kernel with the retpoline compiler options to guard against
2466	  kernel-to-user data leaks by avoiding speculative indirect
2467	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2468	  support for full protection. The kernel may run slower.
2469
2470config MITIGATION_RETHUNK
2471	bool "Enable return-thunks"
2472	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2473	select OBJTOOL if HAVE_OBJTOOL
2474	default y if X86_64
2475	help
2476	  Compile the kernel with the return-thunks compiler option to guard
2477	  against kernel-to-user data leaks by avoiding return speculation.
2478	  Requires a compiler with -mfunction-return=thunk-extern
2479	  support for full protection. The kernel may run slower.
2480
2481config MITIGATION_UNRET_ENTRY
2482	bool "Enable UNRET on kernel entry"
2483	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2484	default y
2485	help
2486	  Compile the kernel with support for the retbleed=unret mitigation.
2487
2488config MITIGATION_CALL_DEPTH_TRACKING
2489	bool "Mitigate RSB underflow with call depth tracking"
2490	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2491	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2492	select CALL_THUNKS
2493	default y
2494	help
2495	  Compile the kernel with call depth tracking to mitigate the Intel
2496	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2497	  by default and needs to be enabled on the kernel command line via the
2498	  retbleed=stuff option. For non-affected systems the overhead of this
2499	  option is marginal as the call depth tracking is using run-time
2500	  generated call thunks in a compiler generated padding area and call
2501	  patching. This increases text size by ~5%. For non affected systems
2502	  this space is unused. On affected SKL systems this results in a
2503	  significant performance gain over the IBRS mitigation.
2504
2505config CALL_THUNKS_DEBUG
2506	bool "Enable call thunks and call depth tracking debugging"
2507	depends on MITIGATION_CALL_DEPTH_TRACKING
2508	select FUNCTION_ALIGNMENT_32B
2509	default n
2510	help
2511	  Enable call/ret counters for imbalance detection and build in
2512	  a noisy dmesg about callthunks generation and call patching for
2513	  trouble shooting. The debug prints need to be enabled on the
2514	  kernel command line with 'debug-callthunks'.
2515	  Only enable this when you are debugging call thunks as this
2516	  creates a noticeable runtime overhead. If unsure say N.
2517
2518config MITIGATION_IBPB_ENTRY
2519	bool "Enable IBPB on kernel entry"
2520	depends on CPU_SUP_AMD && X86_64
2521	default y
2522	help
2523	  Compile the kernel with support for the retbleed=ibpb and
2524	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2525
2526config MITIGATION_IBRS_ENTRY
2527	bool "Enable IBRS on kernel entry"
2528	depends on CPU_SUP_INTEL && X86_64
2529	default y
2530	help
2531	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2532	  This mitigates both spectre_v2 and retbleed at great cost to
2533	  performance.
2534
2535config MITIGATION_SRSO
2536	bool "Mitigate speculative RAS overflow on AMD"
2537	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2538	default y
2539	help
2540	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2541
2542config MITIGATION_SLS
2543	bool "Mitigate Straight-Line-Speculation"
2544	depends on CC_HAS_SLS && X86_64
2545	select OBJTOOL if HAVE_OBJTOOL
2546	default n
2547	help
2548	  Compile the kernel with straight-line-speculation options to guard
2549	  against straight line speculation. The kernel image might be slightly
2550	  larger.
2551
2552config MITIGATION_GDS
2553	bool "Mitigate Gather Data Sampling"
2554	depends on CPU_SUP_INTEL
2555	default y
2556	help
2557	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2558	  vulnerability which allows unprivileged speculative access to data
2559	  which was previously stored in vector registers. The attacker uses gather
2560	  instructions to infer the stale vector register data.
2561
2562config MITIGATION_RFDS
2563	bool "RFDS Mitigation"
2564	depends on CPU_SUP_INTEL
2565	default y
2566	help
2567	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2568	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2569	  allows unprivileged speculative access to stale data previously
2570	  stored in floating point, vector and integer registers.
2571	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2572
2573config MITIGATION_SPECTRE_BHI
2574	bool "Mitigate Spectre-BHB (Branch History Injection)"
2575	depends on CPU_SUP_INTEL
2576	default y
2577	help
2578	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2579	  where the branch history buffer is poisoned to speculatively steer
2580	  indirect branches.
2581	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2582
2583config MITIGATION_MDS
2584	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2585	depends on CPU_SUP_INTEL
2586	default y
2587	help
2588	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2589	  a hardware vulnerability which allows unprivileged speculative access
2590	  to data which is available in various CPU internal buffers.
2591	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2592
2593config MITIGATION_TAA
2594	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2595	depends on CPU_SUP_INTEL
2596	default y
2597	help
2598	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2599	  vulnerability that allows unprivileged speculative access to data
2600	  which is available in various CPU internal buffers by using
2601	  asynchronous aborts within an Intel TSX transactional region.
2602	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2603
2604config MITIGATION_MMIO_STALE_DATA
2605	bool "Mitigate MMIO Stale Data hardware bug"
2606	depends on CPU_SUP_INTEL
2607	default y
2608	help
2609	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2610	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2611	  vulnerabilities that can expose data. The vulnerabilities require the
2612	  attacker to have access to MMIO.
2613	  See also
2614	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2615
2616config MITIGATION_L1TF
2617	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2618	depends on CPU_SUP_INTEL
2619	default y
2620	help
2621	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2622	  hardware vulnerability which allows unprivileged speculative access to data
2623	  available in the Level 1 Data Cache.
2624	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2625
2626config MITIGATION_RETBLEED
2627	bool "Mitigate RETBleed hardware bug"
2628	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2629	default y
2630	help
2631	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2632	  with Return Instructions) vulnerability.  RETBleed is a speculative
2633	  execution attack which takes advantage of microarchitectural behavior
2634	  in many modern microprocessors, similar to Spectre v2. An
2635	  unprivileged attacker can use these flaws to bypass conventional
2636	  memory security restrictions to gain read access to privileged memory
2637	  that would otherwise be inaccessible.
2638
2639config MITIGATION_SPECTRE_V1
2640	bool "Mitigate SPECTRE V1 hardware bug"
2641	default y
2642	help
2643	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2644	  class of side channel attacks that takes advantage of speculative
2645	  execution that bypasses conditional branch instructions used for
2646	  memory access bounds check.
2647	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2648
2649config MITIGATION_SPECTRE_V2
2650	bool "Mitigate SPECTRE V2 hardware bug"
2651	default y
2652	help
2653	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2654	  V2 is a class of side channel attacks that takes advantage of
2655	  indirect branch predictors inside the processor. In Spectre variant 2
2656	  attacks, the attacker can steer speculative indirect branches in the
2657	  victim to gadget code by poisoning the branch target buffer of a CPU
2658	  used for predicting indirect branch addresses.
2659	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2660
2661config MITIGATION_SRBDS
2662	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2663	depends on CPU_SUP_INTEL
2664	default y
2665	help
2666	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2667	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2668	  Sampling (MDS) techniques to infer values returned from special
2669	  register accesses. An unprivileged user can extract values returned
2670	  from RDRAND and RDSEED executed on another core or sibling thread
2671	  using MDS techniques.
2672	  See also
2673	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2674
2675config MITIGATION_SSB
2676	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2677	default y
2678	help
2679	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2680	  hardware security vulnerability and its exploitation takes advantage
2681	  of speculative execution in a similar way to the Meltdown and Spectre
2682	  security vulnerabilities.
2683
2684config MITIGATION_ITS
2685	bool "Enable Indirect Target Selection mitigation"
2686	depends on CPU_SUP_INTEL && X86_64
2687	depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK
2688	select EXECMEM
2689	default y
2690	help
2691	  Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in
2692	  BPU on some Intel CPUs that may allow Spectre V2 style attacks. If
2693	  disabled, mitigation cannot be enabled via cmdline.
2694	  See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst>
2695
2696config MITIGATION_TSA
2697	bool "Mitigate Transient Scheduler Attacks"
2698	depends on CPU_SUP_AMD
2699	default y
2700	help
2701	  Enable mitigation for Transient Scheduler Attacks. TSA is a hardware
2702	  security vulnerability on AMD CPUs which can lead to forwarding of
2703	  invalid info to subsequent instructions and thus can affect their
2704	  timing and thereby cause a leakage.
2705
2706config MITIGATION_VMSCAPE
2707	bool "Mitigate VMSCAPE"
2708	depends on KVM
2709	default y
2710	help
2711	  Enable mitigation for VMSCAPE attacks. VMSCAPE is a hardware security
2712	  vulnerability on Intel and AMD CPUs that may allow a guest to do
2713	  Spectre v2 style attacks on userspace hypervisor.
2714endif
2715
2716config ARCH_HAS_ADD_PAGES
2717	def_bool y
2718	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2719
2720menu "Power management and ACPI options"
2721
2722config ARCH_HIBERNATION_HEADER
2723	def_bool y
2724	depends on HIBERNATION
2725
2726source "kernel/power/Kconfig"
2727
2728source "drivers/acpi/Kconfig"
2729
2730config X86_APM_BOOT
2731	def_bool y
2732	depends on APM
2733
2734menuconfig APM
2735	tristate "APM (Advanced Power Management) BIOS support"
2736	depends on X86_32 && PM_SLEEP
2737	help
2738	  APM is a BIOS specification for saving power using several different
2739	  techniques. This is mostly useful for battery powered laptops with
2740	  APM compliant BIOSes. If you say Y here, the system time will be
2741	  reset after a RESUME operation, the /proc/apm device will provide
2742	  battery status information, and user-space programs will receive
2743	  notification of APM "events" (e.g. battery status change).
2744
2745	  If you select "Y" here, you can disable actual use of the APM
2746	  BIOS by passing the "apm=off" option to the kernel at boot time.
2747
2748	  Note that the APM support is almost completely disabled for
2749	  machines with more than one CPU.
2750
2751	  In order to use APM, you will need supporting software. For location
2752	  and more information, read <file:Documentation/power/apm-acpi.rst>
2753	  and the Battery Powered Linux mini-HOWTO, available from
2754	  <http://www.tldp.org/docs.html#howto>.
2755
2756	  This driver does not spin down disk drives (see the hdparm(8)
2757	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2758	  VESA-compliant "green" monitors.
2759
2760	  Generally, if you don't have a battery in your machine, there isn't
2761	  much point in using this driver and you should say N. If you get
2762	  random kernel OOPSes or reboots that don't seem to be related to
2763	  anything, try disabling/enabling this option (or disabling/enabling
2764	  APM in your BIOS).
2765
2766	  Some other things you should try when experiencing seemingly random,
2767	  "weird" problems:
2768
2769	  1) make sure that you have enough swap space and that it is
2770	  enabled.
2771	  2) pass the "idle=poll" option to the kernel
2772	  3) switch on floating point emulation in the kernel and pass
2773	  the "no387" option to the kernel
2774	  4) pass the "floppy=nodma" option to the kernel
2775	  5) pass the "mem=4M" option to the kernel (thereby disabling
2776	  all but the first 4 MB of RAM)
2777	  6) make sure that the CPU is not over clocked.
2778	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2779	  8) disable the cache from your BIOS settings
2780	  9) install a fan for the video card or exchange video RAM
2781	  10) install a better fan for the CPU
2782	  11) exchange RAM chips
2783	  12) exchange the motherboard.
2784
2785	  To compile this driver as a module, choose M here: the
2786	  module will be called apm.
2787
2788if APM
2789
2790config APM_IGNORE_USER_SUSPEND
2791	bool "Ignore USER SUSPEND"
2792	help
2793	  This option will ignore USER SUSPEND requests. On machines with a
2794	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2795	  series notebooks, it is necessary to say Y because of a BIOS bug.
2796
2797config APM_DO_ENABLE
2798	bool "Enable PM at boot time"
2799	help
2800	  Enable APM features at boot time. From page 36 of the APM BIOS
2801	  specification: "When disabled, the APM BIOS does not automatically
2802	  power manage devices, enter the Standby State, enter the Suspend
2803	  State, or take power saving steps in response to CPU Idle calls."
2804	  This driver will make CPU Idle calls when Linux is idle (unless this
2805	  feature is turned off -- see "Do CPU IDLE calls", below). This
2806	  should always save battery power, but more complicated APM features
2807	  will be dependent on your BIOS implementation. You may need to turn
2808	  this option off if your computer hangs at boot time when using APM
2809	  support, or if it beeps continuously instead of suspending. Turn
2810	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2811	  T400CDT. This is off by default since most machines do fine without
2812	  this feature.
2813
2814config APM_CPU_IDLE
2815	depends on CPU_IDLE
2816	bool "Make CPU Idle calls when idle"
2817	help
2818	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2819	  On some machines, this can activate improved power savings, such as
2820	  a slowed CPU clock rate, when the machine is idle. These idle calls
2821	  are made after the idle loop has run for some length of time (e.g.,
2822	  333 mS). On some machines, this will cause a hang at boot time or
2823	  whenever the CPU becomes idle. (On machines with more than one CPU,
2824	  this option does nothing.)
2825
2826config APM_DISPLAY_BLANK
2827	bool "Enable console blanking using APM"
2828	help
2829	  Enable console blanking using the APM. Some laptops can use this to
2830	  turn off the LCD backlight when the screen blanker of the Linux
2831	  virtual console blanks the screen. Note that this is only used by
2832	  the virtual console screen blanker, and won't turn off the backlight
2833	  when using the X Window system. This also doesn't have anything to
2834	  do with your VESA-compliant power-saving monitor. Further, this
2835	  option doesn't work for all laptops -- it might not turn off your
2836	  backlight at all, or it might print a lot of errors to the console,
2837	  especially if you are using gpm.
2838
2839config APM_ALLOW_INTS
2840	bool "Allow interrupts during APM BIOS calls"
2841	help
2842	  Normally we disable external interrupts while we are making calls to
2843	  the APM BIOS as a measure to lessen the effects of a badly behaving
2844	  BIOS implementation.  The BIOS should reenable interrupts if it
2845	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2846	  many of the newer IBM Thinkpads.  If you experience hangs when you
2847	  suspend, try setting this to Y.  Otherwise, say N.
2848
2849endif # APM
2850
2851source "drivers/cpufreq/Kconfig"
2852
2853source "drivers/cpuidle/Kconfig"
2854
2855source "drivers/idle/Kconfig"
2856
2857endmenu
2858
2859menu "Bus options (PCI etc.)"
2860
2861choice
2862	prompt "PCI access mode"
2863	depends on X86_32 && PCI
2864	default PCI_GOANY
2865	help
2866	  On PCI systems, the BIOS can be used to detect the PCI devices and
2867	  determine their configuration. However, some old PCI motherboards
2868	  have BIOS bugs and may crash if this is done. Also, some embedded
2869	  PCI-based systems don't have any BIOS at all. Linux can also try to
2870	  detect the PCI hardware directly without using the BIOS.
2871
2872	  With this option, you can specify how Linux should detect the
2873	  PCI devices. If you choose "BIOS", the BIOS will be used,
2874	  if you choose "Direct", the BIOS won't be used, and if you
2875	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2876	  If you choose "Any", the kernel will try MMCONFIG, then the
2877	  direct access method and falls back to the BIOS if that doesn't
2878	  work. If unsure, go with the default, which is "Any".
2879
2880config PCI_GOBIOS
2881	bool "BIOS"
2882
2883config PCI_GOMMCONFIG
2884	bool "MMConfig"
2885
2886config PCI_GODIRECT
2887	bool "Direct"
2888
2889config PCI_GOOLPC
2890	bool "OLPC XO-1"
2891	depends on OLPC
2892
2893config PCI_GOANY
2894	bool "Any"
2895
2896endchoice
2897
2898config PCI_BIOS
2899	def_bool y
2900	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2901
2902# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2903config PCI_DIRECT
2904	def_bool y
2905	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2906
2907config PCI_MMCONFIG
2908	bool "Support mmconfig PCI config space access" if X86_64
2909	default y
2910	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2911	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2912	help
2913	  Add support for accessing the PCI configuration space as a memory
2914	  mapped area. It is the recommended method if the system supports
2915	  this (it must have PCI Express and ACPI for it to be available).
2916
2917	  In the unlikely case that enabling this configuration option causes
2918	  problems, the mechanism can be switched off with the 'pci=nommconf'
2919	  command line parameter.
2920
2921	  Say N only if you are sure that your platform does not support this
2922	  access method or you have problems caused by it.
2923
2924	  Say Y otherwise.
2925
2926config PCI_OLPC
2927	def_bool y
2928	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2929
2930config PCI_XEN
2931	def_bool y
2932	depends on PCI && XEN
2933
2934config MMCONF_FAM10H
2935	def_bool y
2936	depends on X86_64 && PCI_MMCONFIG && ACPI
2937
2938config PCI_CNB20LE_QUIRK
2939	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2940	depends on X86_32 && PCI
2941	help
2942	  Read the PCI windows out of the CNB20LE host bridge. This allows
2943	  PCI hotplug to work on systems with the CNB20LE chipset which do
2944	  not have ACPI.
2945
2946	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2947	  most probably only for Pentium III.
2948
2949	  To find out if you have such a chipset, search for a PCI device with
2950	  1166:0009 PCI IDs, for example by executing
2951		lspci -nn | grep '1166:0009'
2952	  The code is inactive if there is none.
2953
2954	  There's no public spec for this chipset, and this functionality
2955	  is known to be incomplete.
2956
2957	  You should say N unless you know you need this.
2958
2959config ISA_BUS
2960	bool "ISA bus support on modern systems" if EXPERT
2961	help
2962	  Expose ISA bus device drivers and options available for selection and
2963	  configuration. Enable this option if your target machine has an ISA
2964	  bus. ISA is an older system, displaced by PCI and newer bus
2965	  architectures -- if your target machine is modern, it probably does
2966	  not have an ISA bus.
2967
2968	  If unsure, say N.
2969
2970# x86_64 have no ISA slots, but can have ISA-style DMA.
2971config ISA_DMA_API
2972	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2973	default y
2974	help
2975	  Enables ISA-style DMA support for devices requiring such controllers.
2976	  If unsure, say Y.
2977
2978if X86_32
2979
2980config ISA
2981	bool "ISA support"
2982	help
2983	  Find out whether you have ISA slots on your motherboard.  ISA is the
2984	  name of a bus system, i.e. the way the CPU talks to the other stuff
2985	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2986	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2987	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2988
2989config SCx200
2990	tristate "NatSemi SCx200 support"
2991	help
2992	  This provides basic support for National Semiconductor's
2993	  (now AMD's) Geode processors.  The driver probes for the
2994	  PCI-IDs of several on-chip devices, so its a good dependency
2995	  for other scx200_* drivers.
2996
2997	  If compiled as a module, the driver is named scx200.
2998
2999config SCx200HR_TIMER
3000	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
3001	depends on SCx200
3002	default y
3003	help
3004	  This driver provides a clocksource built upon the on-chip
3005	  27MHz high-resolution timer.  Its also a workaround for
3006	  NSC Geode SC-1100's buggy TSC, which loses time when the
3007	  processor goes idle (as is done by the scheduler).  The
3008	  other workaround is idle=poll boot option.
3009
3010config OLPC
3011	bool "One Laptop Per Child support"
3012	depends on !X86_PAE
3013	select GPIOLIB
3014	select OF
3015	select OF_PROMTREE
3016	select IRQ_DOMAIN
3017	select OLPC_EC
3018	help
3019	  Add support for detecting the unique features of the OLPC
3020	  XO hardware.
3021
3022config OLPC_XO1_PM
3023	bool "OLPC XO-1 Power Management"
3024	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3025	help
3026	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3027
3028config OLPC_XO1_RTC
3029	bool "OLPC XO-1 Real Time Clock"
3030	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3031	help
3032	  Add support for the XO-1 real time clock, which can be used as a
3033	  programmable wakeup source.
3034
3035config OLPC_XO1_SCI
3036	bool "OLPC XO-1 SCI extras"
3037	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3038	depends on INPUT=y
3039	select POWER_SUPPLY
3040	help
3041	  Add support for SCI-based features of the OLPC XO-1 laptop:
3042	   - EC-driven system wakeups
3043	   - Power button
3044	   - Ebook switch
3045	   - Lid switch
3046	   - AC adapter status updates
3047	   - Battery status updates
3048
3049config OLPC_XO15_SCI
3050	bool "OLPC XO-1.5 SCI extras"
3051	depends on OLPC && ACPI
3052	select POWER_SUPPLY
3053	help
3054	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3055	   - EC-driven system wakeups
3056	   - AC adapter status updates
3057	   - Battery status updates
3058
3059config GEODE_COMMON
3060	bool
3061
3062config ALIX
3063	bool "PCEngines ALIX System Support (LED setup)"
3064	select GPIOLIB
3065	select GEODE_COMMON
3066	help
3067	  This option enables system support for the PCEngines ALIX.
3068	  At present this just sets up LEDs for GPIO control on
3069	  ALIX2/3/6 boards.  However, other system specific setup should
3070	  get added here.
3071
3072	  Note: You must still enable the drivers for GPIO and LED support
3073	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3074
3075	  Note: You have to set alix.force=1 for boards with Award BIOS.
3076
3077config NET5501
3078	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3079	select GPIOLIB
3080	select GEODE_COMMON
3081	help
3082	  This option enables system support for the Soekris Engineering net5501.
3083
3084config GEOS
3085	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3086	select GPIOLIB
3087	select GEODE_COMMON
3088	depends on DMI
3089	help
3090	  This option enables system support for the Traverse Technologies GEOS.
3091
3092config TS5500
3093	bool "Technologic Systems TS-5500 platform support"
3094	depends on MELAN
3095	select CHECK_SIGNATURE
3096	select NEW_LEDS
3097	select LEDS_CLASS
3098	help
3099	  This option enables system support for the Technologic Systems TS-5500.
3100
3101endif # X86_32
3102
3103config AMD_NB
3104	def_bool y
3105	depends on AMD_NODE
3106
3107config AMD_NODE
3108	def_bool y
3109	depends on CPU_SUP_AMD && PCI
3110
3111endmenu
3112
3113menu "Binary Emulations"
3114
3115config IA32_EMULATION
3116	bool "IA32 Emulation"
3117	depends on X86_64
3118	select ARCH_WANT_OLD_COMPAT_IPC
3119	select BINFMT_ELF
3120	select COMPAT_OLD_SIGACTION
3121	help
3122	  Include code to run legacy 32-bit programs under a
3123	  64-bit kernel. You should likely turn this on, unless you're
3124	  100% sure that you don't have any 32-bit programs left.
3125
3126config IA32_EMULATION_DEFAULT_DISABLED
3127	bool "IA32 emulation disabled by default"
3128	default n
3129	depends on IA32_EMULATION
3130	help
3131	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3132	  processes and access to 32-bit syscalls. If unsure, leave it to its
3133	  default value.
3134
3135config X86_X32_ABI
3136	bool "x32 ABI for 64-bit mode"
3137	depends on X86_64
3138	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3139	# compressed debug sections to x86_x32 properly:
3140	# https://github.com/ClangBuiltLinux/linux/issues/514
3141	# https://github.com/ClangBuiltLinux/linux/issues/1141
3142	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3143	help
3144	  Include code to run binaries for the x32 native 32-bit ABI
3145	  for 64-bit processors.  An x32 process gets access to the
3146	  full 64-bit register file and wide data path while leaving
3147	  pointers at 32 bits for smaller memory footprint.
3148
3149config COMPAT_32
3150	def_bool y
3151	depends on IA32_EMULATION || X86_32
3152	select HAVE_UID16
3153	select OLD_SIGSUSPEND3
3154
3155config COMPAT
3156	def_bool y
3157	depends on IA32_EMULATION || X86_X32_ABI
3158
3159config COMPAT_FOR_U64_ALIGNMENT
3160	def_bool y
3161	depends on COMPAT
3162
3163endmenu
3164
3165config HAVE_ATOMIC_IOMAP
3166	def_bool y
3167	depends on X86_32
3168
3169source "arch/x86/kvm/Kconfig"
3170
3171source "arch/x86/Kconfig.cpufeatures"
3172
3173source "arch/x86/Kconfig.assembler"
3174