xref: /linux/arch/x86/Kconfig (revision 9f15e0f9ef514b8e1a80707931f6d07362e8ebc4)
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_HAS_PTDUMP
29	select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
30	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
31	select ARCH_SUPPORTS_PER_VMA_LOCK
32	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
33	select HAVE_ARCH_SOFT_DIRTY
34	select MODULES_USE_ELF_RELA
35	select NEED_DMA_MAP_STATE
36	select SWIOTLB
37	select ARCH_HAS_ELFCORE_COMPAT
38	select ZONE_DMA32
39	select EXECMEM if DYNAMIC_FTRACE
40	select ACPI_MRRM if ACPI
41
42config FORCE_DYNAMIC_FTRACE
43	def_bool y
44	depends on X86_32
45	depends on FUNCTION_TRACER
46	select DYNAMIC_FTRACE
47	help
48	  We keep the static function tracing (!DYNAMIC_FTRACE) around
49	  in order to test the non static function tracing in the
50	  generic code, as other architectures still use it. But we
51	  only need to keep it around for x86_64. No need to keep it
52	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
53#
54# Arch settings
55#
56# ( Note that options that are marked 'if X86_64' could in principle be
57#   ported to 32-bit as well. )
58#
59config X86
60	def_bool y
61	#
62	# Note: keep this list sorted alphabetically
63	#
64	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
65	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
66	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
67	select ARCH_32BIT_OFF_T			if X86_32
68	select ARCH_CLOCKSOURCE_INIT
69	select ARCH_CONFIGURES_CPU_MITIGATIONS
70	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
71	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
72	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
73	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
74	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
75	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
76	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
77	select ARCH_HAS_CPU_ATTACK_VECTORS	if CPU_MITIGATIONS
78	select ARCH_HAS_CACHE_LINE_SIZE
79	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
80	select ARCH_HAS_CPU_FINALIZE_INIT
81	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
82	select ARCH_HAS_CURRENT_STACK_POINTER
83	select ARCH_HAS_DEBUG_VIRTUAL
84	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
85	select ARCH_HAS_DEVMEM_IS_ALLOWED
86	select ARCH_HAS_DMA_OPS			if GART_IOMMU || XEN
87	select ARCH_HAS_EARLY_DEBUG		if KGDB
88	select ARCH_HAS_ELF_RANDOMIZE
89	select ARCH_HAS_EXECMEM_ROX		if X86_64 && STRICT_MODULE_RWX
90	select ARCH_HAS_FAST_MULTIPLIER
91	select ARCH_HAS_FORTIFY_SOURCE
92	select ARCH_HAS_GCOV_PROFILE_ALL
93	select ARCH_HAS_KCOV			if X86_64
94	select ARCH_HAS_KERNEL_FPU_SUPPORT
95	select ARCH_HAS_MEM_ENCRYPT
96	select ARCH_HAS_MEMBARRIER_SYNC_CORE
97	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
98	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
99	select ARCH_HAS_PMEM_API		if X86_64
100	select ARCH_HAS_PREEMPT_LAZY
101	select ARCH_HAS_PTE_SPECIAL
102	select ARCH_HAS_HW_PTE_YOUNG
103	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
104	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
105	select ARCH_HAS_COPY_MC			if X86_64
106	select ARCH_HAS_SET_MEMORY
107	select ARCH_HAS_SET_DIRECT_MAP
108	select ARCH_HAS_STRICT_KERNEL_RWX
109	select ARCH_HAS_STRICT_MODULE_RWX
110	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
111	select ARCH_HAS_SYSCALL_WRAPPER
112	select ARCH_HAS_UBSAN
113	select ARCH_HAS_DEBUG_WX
114	select ARCH_HAS_ZONE_DMA_SET if EXPERT
115	select ARCH_HAVE_NMI_SAFE_CMPXCHG
116	select ARCH_HAVE_EXTRA_ELF_NOTES
117	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
118	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
119	select ARCH_MIGHT_HAVE_PC_PARPORT
120	select ARCH_MIGHT_HAVE_PC_SERIO
121	select ARCH_STACKWALK
122	select ARCH_SUPPORTS_ACPI
123	select ARCH_SUPPORTS_ATOMIC_RMW
124	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
125	select ARCH_SUPPORTS_HUGETLBFS
126	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
127	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
128	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
129	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
130	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
131	select ARCH_SUPPORTS_LTO_CLANG
132	select ARCH_SUPPORTS_LTO_CLANG_THIN
133	select ARCH_SUPPORTS_RT
134	select ARCH_SUPPORTS_AUTOFDO_CLANG
135	select ARCH_SUPPORTS_PROPELLER_CLANG    if X86_64
136	select ARCH_USE_BUILTIN_BSWAP
137	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CX8
138	select ARCH_USE_MEMTEST
139	select ARCH_USE_QUEUED_RWLOCKS
140	select ARCH_USE_QUEUED_SPINLOCKS
141	select ARCH_USE_SYM_ANNOTATIONS
142	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
143	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
144	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
145	select ARCH_WANTS_NO_INSTR
146	select ARCH_WANT_GENERAL_HUGETLB
147	select ARCH_WANT_HUGE_PMD_SHARE		if X86_64
148	select ARCH_WANT_LD_ORPHAN_WARN
149	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
150	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
151	select ARCH_WANT_HUGETLB_VMEMMAP_PREINIT if X86_64
152	select ARCH_WANTS_THP_SWAP		if X86_64
153	select ARCH_HAS_PARANOID_L1D_FLUSH
154	select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
155	select BUILDTIME_TABLE_SORT
156	select CLKEVT_I8253
157	select CLOCKSOURCE_WATCHDOG
158	# Word-size accesses may read uninitialized data past the trailing \0
159	# in strings and cause false KMSAN reports.
160	select DCACHE_WORD_ACCESS		if !KMSAN
161	select DYNAMIC_SIGFRAME
162	select EDAC_ATOMIC_SCRUB
163	select EDAC_SUPPORT
164	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
165	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
166	select GENERIC_CLOCKEVENTS_MIN_ADJUST
167	select GENERIC_CMOS_UPDATE
168	select GENERIC_CPU_AUTOPROBE
169	select GENERIC_CPU_DEVICES
170	select GENERIC_CPU_VULNERABILITIES
171	select GENERIC_EARLY_IOREMAP
172	select GENERIC_ENTRY
173	select GENERIC_IOMAP
174	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
175	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
176	select GENERIC_IRQ_MIGRATION		if SMP
177	select GENERIC_IRQ_PROBE
178	select GENERIC_IRQ_RESERVATION_MODE
179	select GENERIC_IRQ_SHOW
180	select GENERIC_PENDING_IRQ		if SMP
181	select GENERIC_SMP_IDLE_THREAD
182	select GENERIC_TIME_VSYSCALL
183	select GENERIC_GETTIMEOFDAY
184	select GENERIC_VDSO_OVERFLOW_PROTECT
185	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
186	select HARDIRQS_SW_RESEND
187	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
188	select HAS_IOPORT
189	select HAVE_ACPI_APEI			if ACPI
190	select HAVE_ACPI_APEI_NMI		if ACPI
191	select HAVE_ALIGNED_STRUCT_PAGE
192	select HAVE_ARCH_AUDITSYSCALL
193	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
194	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
195	select HAVE_ARCH_JUMP_LABEL
196	select HAVE_ARCH_JUMP_LABEL_RELATIVE
197	select HAVE_ARCH_KASAN			if X86_64
198	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
199	select HAVE_ARCH_KFENCE
200	select HAVE_ARCH_KMSAN			if X86_64
201	select HAVE_ARCH_KGDB
202	select HAVE_ARCH_KSTACK_ERASE
203	select HAVE_ARCH_MMAP_RND_BITS		if MMU
204	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
205	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
206	select HAVE_ARCH_PREL32_RELOCATIONS
207	select HAVE_ARCH_SECCOMP_FILTER
208	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
209	select HAVE_ARCH_TRACEHOOK
210	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
211	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
212	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
213	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
214	select HAVE_ARCH_VMAP_STACK		if X86_64
215	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
216	select HAVE_ARCH_WITHIN_STACK_FRAMES
217	select HAVE_ASM_MODVERSIONS
218	select HAVE_CMPXCHG_DOUBLE
219	select HAVE_CMPXCHG_LOCAL
220	select HAVE_CONTEXT_TRACKING_USER		if X86_64
221	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
222	select HAVE_C_RECORDMCOUNT
223	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
224	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
225	select HAVE_BUILDTIME_MCOUNT_SORT
226	select HAVE_DEBUG_KMEMLEAK
227	select HAVE_DMA_CONTIGUOUS
228	select HAVE_DYNAMIC_FTRACE
229	select HAVE_DYNAMIC_FTRACE_WITH_REGS
230	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
231	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
232	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
233	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
234	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
235	select HAVE_EBPF_JIT
236	select HAVE_EFFICIENT_UNALIGNED_ACCESS
237	select HAVE_EISA			if X86_32
238	select HAVE_EXIT_THREAD
239	select HAVE_GUP_FAST
240	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
241	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
242	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
243	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
244	select HAVE_FUNCTION_TRACER
245	select HAVE_GCC_PLUGINS
246	select HAVE_HW_BREAKPOINT
247	select HAVE_IOREMAP_PROT
248	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
249	select HAVE_IRQ_TIME_ACCOUNTING
250	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
251	select HAVE_KERNEL_BZIP2
252	select HAVE_KERNEL_GZIP
253	select HAVE_KERNEL_LZ4
254	select HAVE_KERNEL_LZMA
255	select HAVE_KERNEL_LZO
256	select HAVE_KERNEL_XZ
257	select HAVE_KERNEL_ZSTD
258	select HAVE_KPROBES
259	select HAVE_KPROBES_ON_FTRACE
260	select HAVE_FUNCTION_ERROR_INJECTION
261	select HAVE_KRETPROBES
262	select HAVE_RETHOOK
263	select HAVE_LIVEPATCH			if X86_64
264	select HAVE_MIXED_BREAKPOINTS_REGS
265	select HAVE_MOD_ARCH_SPECIFIC
266	select HAVE_MOVE_PMD
267	select HAVE_MOVE_PUD
268	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
269	select HAVE_NMI
270	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
271	select HAVE_OBJTOOL			if X86_64
272	select HAVE_OPTPROBES
273	select HAVE_PAGE_SIZE_4KB
274	select HAVE_PCSPKR_PLATFORM
275	select HAVE_PERF_EVENTS
276	select HAVE_PERF_EVENTS_NMI
277	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
278	select HAVE_PCI
279	select HAVE_PERF_REGS
280	select HAVE_PERF_USER_STACK_DUMP
281	select MMU_GATHER_RCU_TABLE_FREE
282	select MMU_GATHER_MERGE_VMAS
283	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
284	select HAVE_REGS_AND_STACK_ACCESS_API
285	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
286	select HAVE_FUNCTION_ARG_ACCESS_API
287	select HAVE_SETUP_PER_CPU_AREA
288	select HAVE_SOFTIRQ_ON_OWN_STACK
289	select HAVE_STACKPROTECTOR
290	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
291	select HAVE_STATIC_CALL
292	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
293	select HAVE_PREEMPT_DYNAMIC_CALL
294	select HAVE_RSEQ
295	select HAVE_RUST			if X86_64
296	select HAVE_SYSCALL_TRACEPOINTS
297	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
298	select HAVE_UNSTABLE_SCHED_CLOCK
299	select HAVE_USER_RETURN_NOTIFIER
300	select HAVE_GENERIC_VDSO
301	select VDSO_GETRANDOM			if X86_64
302	select HOTPLUG_PARALLEL			if SMP && X86_64
303	select HOTPLUG_SMT			if SMP
304	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
305	select IRQ_FORCED_THREADING
306	select LOCK_MM_AND_FIND_VMA
307	select NEED_PER_CPU_EMBED_FIRST_CHUNK
308	select NEED_PER_CPU_PAGE_FIRST_CHUNK
309	select NEED_SG_DMA_LENGTH
310	select NUMA_MEMBLKS			if NUMA
311	select PCI_DOMAINS			if PCI
312	select PCI_LOCKLESS_CONFIG		if PCI
313	select PERF_EVENTS
314	select RTC_LIB
315	select RTC_MC146818_LIB
316	select SPARSE_IRQ
317	select SYSCTL_EXCEPTION_TRACE
318	select THREAD_INFO_IN_TASK
319	select TRACE_IRQFLAGS_SUPPORT
320	select TRACE_IRQFLAGS_NMI_SUPPORT
321	select USER_STACKTRACE_SUPPORT
322	select HAVE_ARCH_KCSAN			if X86_64
323	select PROC_PID_ARCH_STATUS		if PROC_FS
324	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
325	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
326	select FUNCTION_ALIGNMENT_4B
327	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
328	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
329	select ARCH_SUPPORTS_PT_RECLAIM		if X86_64
330
331config INSTRUCTION_DECODER
332	def_bool y
333	depends on KPROBES || PERF_EVENTS || UPROBES
334
335config OUTPUT_FORMAT
336	string
337	default "elf32-i386" if X86_32
338	default "elf64-x86-64" if X86_64
339
340config LOCKDEP_SUPPORT
341	def_bool y
342
343config STACKTRACE_SUPPORT
344	def_bool y
345
346config MMU
347	def_bool y
348
349config ARCH_MMAP_RND_BITS_MIN
350	default 28 if 64BIT
351	default 8
352
353config ARCH_MMAP_RND_BITS_MAX
354	default 32 if 64BIT
355	default 16
356
357config ARCH_MMAP_RND_COMPAT_BITS_MIN
358	default 8
359
360config ARCH_MMAP_RND_COMPAT_BITS_MAX
361	default 16
362
363config SBUS
364	bool
365
366config GENERIC_ISA_DMA
367	def_bool y
368	depends on ISA_DMA_API
369
370config GENERIC_CSUM
371	bool
372	default y if KMSAN || KASAN
373
374config GENERIC_BUG
375	def_bool y
376	depends on BUG
377	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
378
379config GENERIC_BUG_RELATIVE_POINTERS
380	bool
381
382config ARCH_MAY_HAVE_PC_FDC
383	def_bool y
384	depends on ISA_DMA_API
385
386config GENERIC_CALIBRATE_DELAY
387	def_bool y
388
389config ARCH_HAS_CPU_RELAX
390	def_bool y
391
392config ARCH_HIBERNATION_POSSIBLE
393	def_bool y
394
395config ARCH_SUSPEND_POSSIBLE
396	def_bool y
397
398config AUDIT_ARCH
399	def_bool y if X86_64
400
401config KASAN_SHADOW_OFFSET
402	hex
403	depends on KASAN
404	default 0xdffffc0000000000
405
406config HAVE_INTEL_TXT
407	def_bool y
408	depends on INTEL_IOMMU && ACPI
409
410config X86_64_SMP
411	def_bool y
412	depends on X86_64 && SMP
413
414config ARCH_SUPPORTS_UPROBES
415	def_bool y
416
417config FIX_EARLYCON_MEM
418	def_bool y
419
420config DYNAMIC_PHYSICAL_MASK
421	bool
422
423config PGTABLE_LEVELS
424	int
425	default 5 if X86_64
426	default 3 if X86_PAE
427	default 2
428
429menu "Processor type and features"
430
431config SMP
432	bool "Symmetric multi-processing support"
433	help
434	  This enables support for systems with more than one CPU. If you have
435	  a system with only one CPU, say N. If you have a system with more
436	  than one CPU, say Y.
437
438	  If you say N here, the kernel will run on uni- and multiprocessor
439	  machines, but will use only one CPU of a multiprocessor machine. If
440	  you say Y here, the kernel will run on many, but not all,
441	  uniprocessor machines. On a uniprocessor machine, the kernel
442	  will run faster if you say N here.
443
444	  Note that if you say Y here and choose architecture "586" or
445	  "Pentium" under "Processor family", the kernel will not work on 486
446	  architectures. Similarly, multiprocessor kernels for the "PPro"
447	  architecture may not work on all Pentium based boards.
448
449	  People using multiprocessor machines who say Y here should also say
450	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
451	  Management" code will be disabled if you say Y here.
452
453	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
454	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
455	  <http://www.tldp.org/docs.html#howto>.
456
457	  If you don't know what to do here, say N.
458
459config X86_X2APIC
460	bool "x2APIC interrupt controller architecture support"
461	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
462	default y
463	help
464	  x2APIC is an interrupt controller architecture, a component of which
465	  (the local APIC) is present in the CPU. It allows faster access to
466	  the local APIC and supports a larger number of CPUs in the system
467	  than the predecessors.
468
469	  x2APIC was introduced in Intel CPUs around 2008 and in AMD EPYC CPUs
470	  in 2019, but it can be disabled by the BIOS. It is also frequently
471	  emulated in virtual machines, even when the host CPU does not support
472	  it. Support in the CPU can be checked by executing
473		grep x2apic /proc/cpuinfo
474
475	  If this configuration option is disabled, the kernel will boot with
476	  very reduced functionality and performance on some platforms that
477	  have x2APIC enabled. On the other hand, on hardware that does not
478	  support x2APIC, a kernel with this option enabled will just fallback
479	  to older APIC implementations.
480
481	  If in doubt, say Y.
482
483config X86_POSTED_MSI
484	bool "Enable MSI and MSI-x delivery by posted interrupts"
485	depends on X86_64 && IRQ_REMAP
486	help
487	  This enables MSIs that are under interrupt remapping to be delivered as
488	  posted interrupts to the host kernel. Interrupt throughput can
489	  potentially be improved by coalescing CPU notifications during high
490	  frequency bursts.
491
492	  If you don't know what to do here, say N.
493
494config X86_MPPARSE
495	bool "Enable MPS table" if ACPI
496	default y
497	depends on X86_LOCAL_APIC
498	help
499	  For old smp systems that do not have proper acpi support. Newer systems
500	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
501
502config X86_CPU_RESCTRL
503	bool "x86 CPU resource control support"
504	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
505	depends on MISC_FILESYSTEMS
506	select ARCH_HAS_CPU_RESCTRL
507	select RESCTRL_FS
508	select RESCTRL_FS_PSEUDO_LOCK
509	help
510	  Enable x86 CPU resource control support.
511
512	  Provide support for the allocation and monitoring of system resources
513	  usage by the CPU.
514
515	  Intel calls this Intel Resource Director Technology
516	  (Intel(R) RDT). More information about RDT can be found in the
517	  Intel x86 Architecture Software Developer Manual.
518
519	  AMD calls this AMD Platform Quality of Service (AMD QoS).
520	  More information about AMD QoS can be found in the AMD64 Technology
521	  Platform Quality of Service Extensions manual.
522
523	  Say N if unsure.
524
525config X86_FRED
526	bool "Flexible Return and Event Delivery"
527	depends on X86_64
528	help
529	  When enabled, try to use Flexible Return and Event Delivery
530	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
531	  ring transitions and exception/interrupt handling if the
532	  system supports it.
533
534config X86_EXTENDED_PLATFORM
535	bool "Support for extended (non-PC) x86 platforms"
536	default y
537	help
538	  If you disable this option then the kernel will only support
539	  standard PC platforms. (which covers the vast majority of
540	  systems out there.)
541
542	  If you enable this option then you'll be able to select support
543	  for the following non-PC x86 platforms, depending on the value of
544	  CONFIG_64BIT.
545
546	  32-bit platforms (CONFIG_64BIT=n):
547		Goldfish (mostly Android emulator)
548		Intel CE media processor (CE4100) SoC
549		Intel Quark
550		RDC R-321x SoC
551
552	  64-bit platforms (CONFIG_64BIT=y):
553		Numascale NumaChip
554		ScaleMP vSMP
555		SGI Ultraviolet
556		Merrifield/Moorefield MID devices
557		Goldfish (mostly Android emulator)
558
559	  If you have one of these systems, or if you want to build a
560	  generic distribution kernel, say Y here - otherwise say N.
561
562# This is an alphabetically sorted list of 64 bit extended platforms
563# Please maintain the alphabetic order if and when there are additions
564config X86_NUMACHIP
565	bool "Numascale NumaChip"
566	depends on X86_64
567	depends on X86_EXTENDED_PLATFORM
568	depends on NUMA
569	depends on SMP
570	depends on X86_X2APIC
571	depends on PCI_MMCONFIG
572	help
573	  Adds support for Numascale NumaChip large-SMP systems. Needed to
574	  enable more than ~168 cores.
575	  If you don't have one of these, you should say N here.
576
577config X86_VSMP
578	bool "ScaleMP vSMP"
579	select HYPERVISOR_GUEST
580	select PARAVIRT
581	depends on X86_64 && PCI
582	depends on X86_EXTENDED_PLATFORM
583	depends on SMP
584	help
585	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
586	  supposed to run on these EM64T-based machines.  Only choose this option
587	  if you have one of these machines.
588
589config X86_UV
590	bool "SGI Ultraviolet"
591	depends on X86_64
592	depends on X86_EXTENDED_PLATFORM
593	depends on NUMA
594	depends on EFI
595	depends on KEXEC_CORE
596	depends on X86_X2APIC
597	depends on PCI
598	help
599	  This option is needed in order to support SGI Ultraviolet systems.
600	  If you don't have one of these, you should say N here.
601
602config X86_INTEL_MID
603	bool "Intel Z34xx/Z35xx MID platform support"
604	depends on X86_EXTENDED_PLATFORM
605	depends on X86_PLATFORM_DEVICES
606	depends on PCI
607	depends on X86_64 || (EXPERT && PCI_GOANY)
608	depends on X86_IO_APIC
609	select I2C
610	select DW_APB_TIMER
611	select INTEL_SCU_PCI
612	help
613	  Select to build a kernel capable of supporting 64-bit Intel MID
614	  (Mobile Internet Device) platform systems which do not have
615	  the PCI legacy interfaces.
616
617	  The only supported devices are the 22nm Merrified (Z34xx)
618	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
619	  a small number of Android devices such as the Asus Zenfone 2,
620	  Asus FonePad 8 and Dell Venue 7.
621
622	  If you are building for a PC class system or non-MID tablet
623	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
624
625	  Intel MID platforms are based on an Intel processor and chipset which
626	  consume less power than most of the x86 derivatives.
627
628config X86_GOLDFISH
629	bool "Goldfish (Virtual Platform)"
630	depends on X86_EXTENDED_PLATFORM
631	help
632	  Enable support for the Goldfish virtual platform used primarily
633	  for Android development. Unless you are building for the Android
634	  Goldfish emulator say N here.
635
636# Following is an alphabetically sorted list of 32 bit extended platforms
637# Please maintain the alphabetic order if and when there are additions
638
639config X86_INTEL_CE
640	bool "CE4100 TV platform"
641	depends on PCI
642	depends on PCI_GODIRECT
643	depends on X86_IO_APIC
644	depends on X86_32
645	depends on X86_EXTENDED_PLATFORM
646	select X86_REBOOTFIXUPS
647	select OF
648	select OF_EARLY_FLATTREE
649	help
650	  Select for the Intel CE media processor (CE4100) SOC.
651	  This option compiles in support for the CE4100 SOC for settop
652	  boxes and media devices.
653
654config X86_INTEL_QUARK
655	bool "Intel Quark platform support"
656	depends on X86_32
657	depends on X86_EXTENDED_PLATFORM
658	depends on X86_PLATFORM_DEVICES
659	depends on X86_TSC
660	depends on PCI
661	depends on PCI_GOANY
662	depends on X86_IO_APIC
663	select IOSF_MBI
664	select INTEL_IMR
665	select COMMON_CLK
666	help
667	  Select to include support for Quark X1000 SoC.
668	  Say Y here if you have a Quark based system such as the Arduino
669	  compatible Intel Galileo.
670
671config X86_RDC321X
672	bool "RDC R-321x SoC"
673	depends on X86_32
674	depends on X86_EXTENDED_PLATFORM
675	select M486
676	select X86_REBOOTFIXUPS
677	help
678	  This option is needed for RDC R-321x system-on-chip, also known
679	  as R-8610-(G).
680	  If you don't have one of these chips, you should say N here.
681
682config X86_INTEL_LPSS
683	bool "Intel Low Power Subsystem Support"
684	depends on X86 && ACPI && PCI
685	select COMMON_CLK
686	select PINCTRL
687	select IOSF_MBI
688	help
689	  Select to build support for Intel Low Power Subsystem such as
690	  found on Intel Lynxpoint PCH. Selecting this option enables
691	  things like clock tree (common clock framework) and pincontrol
692	  which are needed by the LPSS peripheral drivers.
693
694config X86_AMD_PLATFORM_DEVICE
695	bool "AMD ACPI2Platform devices support"
696	depends on ACPI
697	select COMMON_CLK
698	select PINCTRL
699	help
700	  Select to interpret AMD specific ACPI device to platform device
701	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
702	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
703	  implemented under PINCTRL subsystem.
704
705config IOSF_MBI
706	tristate "Intel SoC IOSF Sideband support for SoC platforms"
707	depends on PCI
708	help
709	  This option enables sideband register access support for Intel SoC
710	  platforms. On these platforms the IOSF sideband is used in lieu of
711	  MSR's for some register accesses, mostly but not limited to thermal
712	  and power. Drivers may query the availability of this device to
713	  determine if they need the sideband in order to work on these
714	  platforms. The sideband is available on the following SoC products.
715	  This list is not meant to be exclusive.
716	   - BayTrail
717	   - Braswell
718	   - Quark
719
720	  You should say Y if you are running a kernel on one of these SoC's.
721
722config IOSF_MBI_DEBUG
723	bool "Enable IOSF sideband access through debugfs"
724	depends on IOSF_MBI && DEBUG_FS
725	help
726	  Select this option to expose the IOSF sideband access registers (MCR,
727	  MDR, MCRX) through debugfs to write and read register information from
728	  different units on the SoC. This is most useful for obtaining device
729	  state information for debug and analysis. As this is a general access
730	  mechanism, users of this option would have specific knowledge of the
731	  device they want to access.
732
733	  If you don't require the option or are in doubt, say N.
734
735config X86_SUPPORTS_MEMORY_FAILURE
736	def_bool y
737	# MCE code calls memory_failure():
738	depends on X86_MCE
739	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
740	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
741	depends on X86_64 || !SPARSEMEM
742	select ARCH_SUPPORTS_MEMORY_FAILURE
743
744config X86_32_IRIS
745	tristate "Eurobraille/Iris poweroff module"
746	depends on X86_32
747	help
748	  The Iris machines from EuroBraille do not have APM or ACPI support
749	  to shut themselves down properly.  A special I/O sequence is
750	  needed to do so, which is what this module does at
751	  kernel shutdown.
752
753	  This is only for Iris machines from EuroBraille.
754
755	  If unused, say N.
756
757config SCHED_OMIT_FRAME_POINTER
758	def_bool y
759	prompt "Single-depth WCHAN output"
760	depends on X86
761	help
762	  Calculate simpler /proc/<PID>/wchan values. If this option
763	  is disabled then wchan values will recurse back to the
764	  caller function. This provides more accurate wchan values,
765	  at the expense of slightly more scheduling overhead.
766
767	  If in doubt, say "Y".
768
769menuconfig HYPERVISOR_GUEST
770	bool "Linux guest support"
771	help
772	  Say Y here to enable options for running Linux under various hyper-
773	  visors. This option enables basic hypervisor detection and platform
774	  setup.
775
776	  If you say N, all options in this submenu will be skipped and
777	  disabled, and Linux guest support won't be built in.
778
779if HYPERVISOR_GUEST
780
781config PARAVIRT
782	bool "Enable paravirtualization code"
783	depends on HAVE_STATIC_CALL
784	help
785	  This changes the kernel so it can modify itself when it is run
786	  under a hypervisor, potentially improving performance significantly
787	  over full virtualization.  However, when run without a hypervisor
788	  the kernel is theoretically slower and slightly larger.
789
790config PARAVIRT_XXL
791	bool
792	depends on X86_64
793
794config PARAVIRT_DEBUG
795	bool "paravirt-ops debugging"
796	depends on PARAVIRT && DEBUG_KERNEL
797	help
798	  Enable to debug paravirt_ops internals.  Specifically, BUG if
799	  a paravirt_op is missing when it is called.
800
801config PARAVIRT_SPINLOCKS
802	bool "Paravirtualization layer for spinlocks"
803	depends on PARAVIRT && SMP
804	help
805	  Paravirtualized spinlocks allow a pvops backend to replace the
806	  spinlock implementation with something virtualization-friendly
807	  (for example, block the virtual CPU rather than spinning).
808
809	  It has a minimal impact on native kernels and gives a nice performance
810	  benefit on paravirtualized KVM / Xen kernels.
811
812	  If you are unsure how to answer this question, answer Y.
813
814config X86_HV_CALLBACK_VECTOR
815	def_bool n
816
817source "arch/x86/xen/Kconfig"
818
819config KVM_GUEST
820	bool "KVM Guest support (including kvmclock)"
821	depends on PARAVIRT
822	select PARAVIRT_CLOCK
823	select ARCH_CPUIDLE_HALTPOLL
824	select X86_HV_CALLBACK_VECTOR
825	default y
826	help
827	  This option enables various optimizations for running under the KVM
828	  hypervisor. It includes a paravirtualized clock, so that instead
829	  of relying on a PIT (or probably other) emulation by the
830	  underlying device model, the host provides the guest with
831	  timing infrastructure such as time of day, and system time
832
833config ARCH_CPUIDLE_HALTPOLL
834	def_bool n
835	prompt "Disable host haltpoll when loading haltpoll driver"
836	help
837	  If virtualized under KVM, disable host haltpoll.
838
839config PVH
840	bool "Support for running PVH guests"
841	help
842	  This option enables the PVH entry point for guest virtual machines
843	  as specified in the x86/HVM direct boot ABI.
844
845config PARAVIRT_TIME_ACCOUNTING
846	bool "Paravirtual steal time accounting"
847	depends on PARAVIRT
848	help
849	  Select this option to enable fine granularity task steal time
850	  accounting. Time spent executing other tasks in parallel with
851	  the current vCPU is discounted from the vCPU power. To account for
852	  that, there can be a small performance impact.
853
854	  If in doubt, say N here.
855
856config PARAVIRT_CLOCK
857	bool
858
859config JAILHOUSE_GUEST
860	bool "Jailhouse non-root cell support"
861	depends on X86_64 && PCI
862	select X86_PM_TIMER
863	help
864	  This option allows to run Linux as guest in a Jailhouse non-root
865	  cell. You can leave this option disabled if you only want to start
866	  Jailhouse and run Linux afterwards in the root cell.
867
868config ACRN_GUEST
869	bool "ACRN Guest support"
870	depends on X86_64
871	select X86_HV_CALLBACK_VECTOR
872	help
873	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
874	  a flexible, lightweight reference open-source hypervisor, built with
875	  real-time and safety-criticality in mind. It is built for embedded
876	  IOT with small footprint and real-time features. More details can be
877	  found in https://projectacrn.org/.
878
879config INTEL_TDX_GUEST
880	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
881	depends on X86_64 && CPU_SUP_INTEL
882	depends on X86_X2APIC
883	depends on EFI_STUB
884	depends on PARAVIRT
885	select ARCH_HAS_CC_PLATFORM
886	select X86_MEM_ENCRYPT
887	select X86_MCE
888	select UNACCEPTED_MEMORY
889	help
890	  Support running as a guest under Intel TDX.  Without this support,
891	  the guest kernel can not boot or run under TDX.
892	  TDX includes memory encryption and integrity capabilities
893	  which protect the confidentiality and integrity of guest
894	  memory contents and CPU state. TDX guests are protected from
895	  some attacks from the VMM.
896
897endif # HYPERVISOR_GUEST
898
899source "arch/x86/Kconfig.cpu"
900
901config HPET_TIMER
902	def_bool X86_64
903	prompt "HPET Timer Support" if X86_32
904	help
905	  Use the IA-PC HPET (High Precision Event Timer) to manage
906	  time in preference to the PIT and RTC, if a HPET is
907	  present.
908	  HPET is the next generation timer replacing legacy 8254s.
909	  The HPET provides a stable time base on SMP
910	  systems, unlike the TSC, but it is more expensive to access,
911	  as it is off-chip.  The interface used is documented
912	  in the HPET spec, revision 1.
913
914	  You can safely choose Y here.  However, HPET will only be
915	  activated if the platform and the BIOS support this feature.
916	  Otherwise the 8254 will be used for timing services.
917
918	  Choose N to continue using the legacy 8254 timer.
919
920config HPET_EMULATE_RTC
921	def_bool y
922	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
923
924# Mark as expert because too many people got it wrong.
925# The code disables itself when not needed.
926config DMI
927	default y
928	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
929	bool "Enable DMI scanning" if EXPERT
930	help
931	  Enabled scanning of DMI to identify machine quirks. Say Y
932	  here unless you have verified that your setup is not
933	  affected by entries in the DMI blacklist. Required by PNP
934	  BIOS code.
935
936config GART_IOMMU
937	bool "Old AMD GART IOMMU support"
938	select IOMMU_HELPER
939	select SWIOTLB
940	depends on X86_64 && PCI && AMD_NB
941	help
942	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
943	  GART based hardware IOMMUs.
944
945	  The GART supports full DMA access for devices with 32-bit access
946	  limitations, on systems with more than 3 GB. This is usually needed
947	  for USB, sound, many IDE/SATA chipsets and some other devices.
948
949	  Newer systems typically have a modern AMD IOMMU, supported via
950	  the CONFIG_AMD_IOMMU=y config option.
951
952	  In normal configurations this driver is only active when needed:
953	  there's more than 3 GB of memory and the system contains a
954	  32-bit limited device.
955
956	  If unsure, say Y.
957
958config BOOT_VESA_SUPPORT
959	bool
960	help
961	  If true, at least one selected framebuffer driver can take advantage
962	  of VESA video modes set at an early boot stage via the vga= parameter.
963
964config MAXSMP
965	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
966	depends on X86_64 && SMP && DEBUG_KERNEL
967	select CPUMASK_OFFSTACK
968	help
969	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
970	  If unsure, say N.
971
972#
973# The maximum number of CPUs supported:
974#
975# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
976# and which can be configured interactively in the
977# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
978#
979# The ranges are different on 32-bit and 64-bit kernels, depending on
980# hardware capabilities and scalability features of the kernel.
981#
982# ( If MAXSMP is enabled we just use the highest possible value and disable
983#   interactive configuration. )
984#
985
986config NR_CPUS_RANGE_BEGIN
987	int
988	default NR_CPUS_RANGE_END if MAXSMP
989	default    1 if !SMP
990	default    2
991
992config NR_CPUS_RANGE_END
993	int
994	depends on X86_32
995	default    8 if  SMP
996	default    1 if !SMP
997
998config NR_CPUS_RANGE_END
999	int
1000	depends on X86_64
1001	default 8192 if  SMP && CPUMASK_OFFSTACK
1002	default  512 if  SMP && !CPUMASK_OFFSTACK
1003	default    1 if !SMP
1004
1005config NR_CPUS_DEFAULT
1006	int
1007	depends on X86_32
1008	default    8 if  SMP
1009	default    1 if !SMP
1010
1011config NR_CPUS_DEFAULT
1012	int
1013	depends on X86_64
1014	default 8192 if  MAXSMP
1015	default   64 if  SMP
1016	default    1 if !SMP
1017
1018config NR_CPUS
1019	int "Maximum number of CPUs" if SMP && !MAXSMP
1020	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1021	default NR_CPUS_DEFAULT
1022	help
1023	  This allows you to specify the maximum number of CPUs which this
1024	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1025	  supported value is 8192, otherwise the maximum value is 512.  The
1026	  minimum value which makes sense is 2.
1027
1028	  This is purely to save memory: each supported CPU adds about 8KB
1029	  to the kernel image.
1030
1031config SCHED_CLUSTER
1032	bool "Cluster scheduler support"
1033	depends on SMP
1034	default y
1035	help
1036	  Cluster scheduler support improves the CPU scheduler's decision
1037	  making when dealing with machines that have clusters of CPUs.
1038	  Cluster usually means a couple of CPUs which are placed closely
1039	  by sharing mid-level caches, last-level cache tags or internal
1040	  busses.
1041
1042config SCHED_SMT
1043	def_bool y if SMP
1044
1045config SCHED_MC
1046	def_bool y
1047	prompt "Multi-core scheduler support"
1048	depends on SMP
1049	help
1050	  Multi-core scheduler support improves the CPU scheduler's decision
1051	  making when dealing with multi-core CPU chips at a cost of slightly
1052	  increased overhead in some places. If unsure say N here.
1053
1054config SCHED_MC_PRIO
1055	bool "CPU core priorities scheduler support"
1056	depends on SCHED_MC
1057	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1058	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1059	select CPU_FREQ
1060	default y
1061	help
1062	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1063	  core ordering determined at manufacturing time, which allows
1064	  certain cores to reach higher turbo frequencies (when running
1065	  single threaded workloads) than others.
1066
1067	  Enabling this kernel feature teaches the scheduler about
1068	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1069	  scheduler's CPU selection logic accordingly, so that higher
1070	  overall system performance can be achieved.
1071
1072	  This feature will have no effect on CPUs without this feature.
1073
1074	  If unsure say Y here.
1075
1076config UP_LATE_INIT
1077	def_bool y
1078	depends on !SMP && X86_LOCAL_APIC
1079
1080config X86_UP_APIC
1081	bool "Local APIC support on uniprocessors" if !PCI_MSI
1082	default PCI_MSI
1083	depends on X86_32 && !SMP
1084	help
1085	  A local APIC (Advanced Programmable Interrupt Controller) is an
1086	  integrated interrupt controller in the CPU. If you have a single-CPU
1087	  system which has a processor with a local APIC, you can say Y here to
1088	  enable and use it. If you say Y here even though your machine doesn't
1089	  have a local APIC, then the kernel will still run with no slowdown at
1090	  all. The local APIC supports CPU-generated self-interrupts (timer,
1091	  performance counters), and the NMI watchdog which detects hard
1092	  lockups.
1093
1094config X86_UP_IOAPIC
1095	bool "IO-APIC support on uniprocessors"
1096	depends on X86_UP_APIC
1097	help
1098	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1099	  SMP-capable replacement for PC-style interrupt controllers. Most
1100	  SMP systems and many recent uniprocessor systems have one.
1101
1102	  If you have a single-CPU system with an IO-APIC, you can say Y here
1103	  to use it. If you say Y here even though your machine doesn't have
1104	  an IO-APIC, then the kernel will still run with no slowdown at all.
1105
1106config X86_LOCAL_APIC
1107	def_bool y
1108	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1109	select IRQ_DOMAIN_HIERARCHY
1110
1111config ACPI_MADT_WAKEUP
1112	def_bool y
1113	depends on X86_64
1114	depends on ACPI
1115	depends on SMP
1116	depends on X86_LOCAL_APIC
1117
1118config X86_IO_APIC
1119	def_bool y
1120	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1121
1122config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1123	bool "Reroute for broken boot IRQs"
1124	depends on X86_IO_APIC
1125	help
1126	  This option enables a workaround that fixes a source of
1127	  spurious interrupts. This is recommended when threaded
1128	  interrupt handling is used on systems where the generation of
1129	  superfluous "boot interrupts" cannot be disabled.
1130
1131	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1132	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1133	  kernel does during interrupt handling). On chipsets where this
1134	  boot IRQ generation cannot be disabled, this workaround keeps
1135	  the original IRQ line masked so that only the equivalent "boot
1136	  IRQ" is delivered to the CPUs. The workaround also tells the
1137	  kernel to set up the IRQ handler on the boot IRQ line. In this
1138	  way only one interrupt is delivered to the kernel. Otherwise
1139	  the spurious second interrupt may cause the kernel to bring
1140	  down (vital) interrupt lines.
1141
1142	  Only affects "broken" chipsets. Interrupt sharing may be
1143	  increased on these systems.
1144
1145config X86_MCE
1146	bool "Machine Check / overheating reporting"
1147	select GENERIC_ALLOCATOR
1148	default y
1149	help
1150	  Machine Check support allows the processor to notify the
1151	  kernel if it detects a problem (e.g. overheating, data corruption).
1152	  The action the kernel takes depends on the severity of the problem,
1153	  ranging from warning messages to halting the machine.
1154
1155config X86_MCELOG_LEGACY
1156	bool "Support for deprecated /dev/mcelog character device"
1157	depends on X86_MCE
1158	help
1159	  Enable support for /dev/mcelog which is needed by the old mcelog
1160	  userspace logging daemon. Consider switching to the new generation
1161	  rasdaemon solution.
1162
1163config X86_MCE_INTEL
1164	def_bool y
1165	prompt "Intel MCE features"
1166	depends on X86_MCE && X86_LOCAL_APIC
1167	help
1168	  Additional support for intel specific MCE features such as
1169	  the thermal monitor.
1170
1171config X86_MCE_AMD
1172	def_bool y
1173	prompt "AMD MCE features"
1174	depends on X86_MCE && X86_LOCAL_APIC
1175	help
1176	  Additional support for AMD specific MCE features such as
1177	  the DRAM Error Threshold.
1178
1179config X86_ANCIENT_MCE
1180	bool "Support for old Pentium 5 / WinChip machine checks"
1181	depends on X86_32 && X86_MCE
1182	help
1183	  Include support for machine check handling on old Pentium 5 or WinChip
1184	  systems. These typically need to be enabled explicitly on the command
1185	  line.
1186
1187config X86_MCE_THRESHOLD
1188	depends on X86_MCE_AMD || X86_MCE_INTEL
1189	def_bool y
1190
1191config X86_MCE_INJECT
1192	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1193	tristate "Machine check injector support"
1194	help
1195	  Provide support for injecting machine checks for testing purposes.
1196	  If you don't know what a machine check is and you don't do kernel
1197	  QA it is safe to say n.
1198
1199source "arch/x86/events/Kconfig"
1200
1201config X86_LEGACY_VM86
1202	bool "Legacy VM86 support"
1203	depends on X86_32
1204	help
1205	  This option allows user programs to put the CPU into V8086
1206	  mode, which is an 80286-era approximation of 16-bit real mode.
1207
1208	  Some very old versions of X and/or vbetool require this option
1209	  for user mode setting.  Similarly, DOSEMU will use it if
1210	  available to accelerate real mode DOS programs.  However, any
1211	  recent version of DOSEMU, X, or vbetool should be fully
1212	  functional even without kernel VM86 support, as they will all
1213	  fall back to software emulation. Nevertheless, if you are using
1214	  a 16-bit DOS program where 16-bit performance matters, vm86
1215	  mode might be faster than emulation and you might want to
1216	  enable this option.
1217
1218	  Note that any app that works on a 64-bit kernel is unlikely to
1219	  need this option, as 64-bit kernels don't, and can't, support
1220	  V8086 mode. This option is also unrelated to 16-bit protected
1221	  mode and is not needed to run most 16-bit programs under Wine.
1222
1223	  Enabling this option increases the complexity of the kernel
1224	  and slows down exception handling a tiny bit.
1225
1226	  If unsure, say N here.
1227
1228config VM86
1229	bool
1230	default X86_LEGACY_VM86
1231
1232config X86_16BIT
1233	bool "Enable support for 16-bit segments" if EXPERT
1234	default y
1235	depends on MODIFY_LDT_SYSCALL
1236	help
1237	  This option is required by programs like Wine to run 16-bit
1238	  protected mode legacy code on x86 processors.  Disabling
1239	  this option saves about 300 bytes on i386, or around 6K text
1240	  plus 16K runtime memory on x86-64,
1241
1242config X86_ESPFIX32
1243	def_bool y
1244	depends on X86_16BIT && X86_32
1245
1246config X86_ESPFIX64
1247	def_bool y
1248	depends on X86_16BIT && X86_64
1249
1250config X86_VSYSCALL_EMULATION
1251	bool "Enable vsyscall emulation" if EXPERT
1252	default y
1253	depends on X86_64
1254	help
1255	  This enables emulation of the legacy vsyscall page.  Disabling
1256	  it is roughly equivalent to booting with vsyscall=none, except
1257	  that it will also disable the helpful warning if a program
1258	  tries to use a vsyscall.  With this option set to N, offending
1259	  programs will just segfault, citing addresses of the form
1260	  0xffffffffff600?00.
1261
1262	  This option is required by many programs built before 2013, and
1263	  care should be used even with newer programs if set to N.
1264
1265	  Disabling this option saves about 7K of kernel size and
1266	  possibly 4K of additional runtime pagetable memory.
1267
1268config X86_IOPL_IOPERM
1269	bool "IOPERM and IOPL Emulation"
1270	default y
1271	help
1272	  This enables the ioperm() and iopl() syscalls which are necessary
1273	  for legacy applications.
1274
1275	  Legacy IOPL support is an overbroad mechanism which allows user
1276	  space aside of accessing all 65536 I/O ports also to disable
1277	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1278	  capabilities and permission from potentially active security
1279	  modules.
1280
1281	  The emulation restricts the functionality of the syscall to
1282	  only allowing the full range I/O port access, but prevents the
1283	  ability to disable interrupts from user space which would be
1284	  granted if the hardware IOPL mechanism would be used.
1285
1286config TOSHIBA
1287	tristate "Toshiba Laptop support"
1288	depends on X86_32
1289	help
1290	  This adds a driver to safely access the System Management Mode of
1291	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1292	  not work on models with a Phoenix BIOS. The System Management Mode
1293	  is used to set the BIOS and power saving options on Toshiba portables.
1294
1295	  For information on utilities to make use of this driver see the
1296	  Toshiba Linux utilities web site at:
1297	  <http://www.buzzard.org.uk/toshiba/>.
1298
1299	  Say Y if you intend to run this kernel on a Toshiba portable.
1300	  Say N otherwise.
1301
1302config X86_REBOOTFIXUPS
1303	bool "Enable X86 board specific fixups for reboot"
1304	depends on X86_32
1305	help
1306	  This enables chipset and/or board specific fixups to be done
1307	  in order to get reboot to work correctly. This is only needed on
1308	  some combinations of hardware and BIOS. The symptom, for which
1309	  this config is intended, is when reboot ends with a stalled/hung
1310	  system.
1311
1312	  Currently, the only fixup is for the Geode machines using
1313	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1314
1315	  Say Y if you want to enable the fixup. Currently, it's safe to
1316	  enable this option even if you don't need it.
1317	  Say N otherwise.
1318
1319config MICROCODE
1320	def_bool y
1321	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1322	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1323
1324config MICROCODE_INITRD32
1325	def_bool y
1326	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1327
1328config MICROCODE_LATE_LOADING
1329	bool "Late microcode loading (DANGEROUS)"
1330	default n
1331	depends on MICROCODE && SMP
1332	help
1333	  Loading microcode late, when the system is up and executing instructions
1334	  is a tricky business and should be avoided if possible. Just the sequence
1335	  of synchronizing all cores and SMT threads is one fragile dance which does
1336	  not guarantee that cores might not softlock after the loading. Therefore,
1337	  use this at your own risk. Late loading taints the kernel unless the
1338	  microcode header indicates that it is safe for late loading via the
1339	  minimal revision check. This minimal revision check can be enforced on
1340	  the kernel command line with "microcode.minrev=Y".
1341
1342config MICROCODE_LATE_FORCE_MINREV
1343	bool "Enforce late microcode loading minimal revision check"
1344	default n
1345	depends on MICROCODE_LATE_LOADING
1346	help
1347	  To prevent that users load microcode late which modifies already
1348	  in use features, newer microcode patches have a minimum revision field
1349	  in the microcode header, which tells the kernel which minimum
1350	  revision must be active in the CPU to safely load that new microcode
1351	  late into the running system. If disabled the check will not
1352	  be enforced but the kernel will be tainted when the minimal
1353	  revision check fails.
1354
1355	  This minimal revision check can also be controlled via the
1356	  "microcode.minrev" parameter on the kernel command line.
1357
1358	  If unsure say Y.
1359
1360config X86_MSR
1361	tristate "/dev/cpu/*/msr - Model-specific register support"
1362	help
1363	  This device gives privileged processes access to the x86
1364	  Model-Specific Registers (MSRs).  It is a character device with
1365	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1366	  MSR accesses are directed to a specific CPU on multi-processor
1367	  systems.
1368
1369config X86_CPUID
1370	tristate "/dev/cpu/*/cpuid - CPU information support"
1371	help
1372	  This device gives processes access to the x86 CPUID instruction to
1373	  be executed on a specific processor.  It is a character device
1374	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1375	  /dev/cpu/31/cpuid.
1376
1377config HIGHMEM4G
1378	bool "High Memory Support"
1379	depends on X86_32
1380	help
1381	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1382	  However, the address space of 32-bit x86 processors is only 4
1383	  Gigabytes large. That means that, if you have a large amount of
1384	  physical memory, not all of it can be "permanently mapped" by the
1385	  kernel. The physical memory that's not permanently mapped is called
1386	  "high memory".
1387
1388	  If you are compiling a kernel which will never run on a machine with
1389	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1390	  choice and suitable for most users). This will result in a "3GB/1GB"
1391	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1392	  space and the remaining part of the 4GB virtual memory space is used
1393	  by the kernel to permanently map as much physical memory as
1394	  possible.
1395
1396	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1397	  answer "Y" here.
1398
1399	  If unsure, say N.
1400
1401choice
1402	prompt "Memory split" if EXPERT
1403	default VMSPLIT_3G
1404	depends on X86_32
1405	help
1406	  Select the desired split between kernel and user memory.
1407
1408	  If the address range available to the kernel is less than the
1409	  physical memory installed, the remaining memory will be available
1410	  as "high memory". Accessing high memory is a little more costly
1411	  than low memory, as it needs to be mapped into the kernel first.
1412	  Note that increasing the kernel address space limits the range
1413	  available to user programs, making the address space there
1414	  tighter.  Selecting anything other than the default 3G/1G split
1415	  will also likely make your kernel incompatible with binary-only
1416	  kernel modules.
1417
1418	  If you are not absolutely sure what you are doing, leave this
1419	  option alone!
1420
1421	config VMSPLIT_3G
1422		bool "3G/1G user/kernel split"
1423	config VMSPLIT_3G_OPT
1424		depends on !X86_PAE
1425		bool "3G/1G user/kernel split (for full 1G low memory)"
1426	config VMSPLIT_2G
1427		bool "2G/2G user/kernel split"
1428	config VMSPLIT_2G_OPT
1429		depends on !X86_PAE
1430		bool "2G/2G user/kernel split (for full 2G low memory)"
1431	config VMSPLIT_1G
1432		bool "1G/3G user/kernel split"
1433endchoice
1434
1435config PAGE_OFFSET
1436	hex
1437	default 0xB0000000 if VMSPLIT_3G_OPT
1438	default 0x80000000 if VMSPLIT_2G
1439	default 0x78000000 if VMSPLIT_2G_OPT
1440	default 0x40000000 if VMSPLIT_1G
1441	default 0xC0000000
1442	depends on X86_32
1443
1444config HIGHMEM
1445	def_bool HIGHMEM4G
1446
1447config X86_PAE
1448	bool "PAE (Physical Address Extension) Support"
1449	depends on X86_32 && X86_HAVE_PAE
1450	select PHYS_ADDR_T_64BIT
1451	help
1452	  PAE is required for NX support, and furthermore enables
1453	  larger swapspace support for non-overcommit purposes. It
1454	  has the cost of more pagetable lookup overhead, and also
1455	  consumes more pagetable space per process.
1456
1457config X86_DIRECT_GBPAGES
1458	def_bool y
1459	depends on X86_64
1460	help
1461	  Certain kernel features effectively disable kernel
1462	  linear 1 GB mappings (even if the CPU otherwise
1463	  supports them), so don't confuse the user by printing
1464	  that we have them enabled.
1465
1466config X86_CPA_STATISTICS
1467	bool "Enable statistic for Change Page Attribute"
1468	depends on DEBUG_FS
1469	help
1470	  Expose statistics about the Change Page Attribute mechanism, which
1471	  helps to determine the effectiveness of preserving large and huge
1472	  page mappings when mapping protections are changed.
1473
1474config X86_MEM_ENCRYPT
1475	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1476	select DYNAMIC_PHYSICAL_MASK
1477	def_bool n
1478
1479config AMD_MEM_ENCRYPT
1480	bool "AMD Secure Memory Encryption (SME) support"
1481	depends on X86_64 && CPU_SUP_AMD
1482	depends on EFI_STUB
1483	select DMA_COHERENT_POOL
1484	select ARCH_USE_MEMREMAP_PROT
1485	select INSTRUCTION_DECODER
1486	select ARCH_HAS_CC_PLATFORM
1487	select X86_MEM_ENCRYPT
1488	select UNACCEPTED_MEMORY
1489	select CRYPTO_LIB_AESGCM
1490	help
1491	  Say yes to enable support for the encryption of system memory.
1492	  This requires an AMD processor that supports Secure Memory
1493	  Encryption (SME).
1494
1495# Common NUMA Features
1496config NUMA
1497	bool "NUMA Memory Allocation and Scheduler Support"
1498	depends on SMP
1499	depends on X86_64
1500	select USE_PERCPU_NUMA_NODE_ID
1501	select OF_NUMA if OF
1502	help
1503	  Enable NUMA (Non-Uniform Memory Access) support.
1504
1505	  The kernel will try to allocate memory used by a CPU on the
1506	  local memory controller of the CPU and add some more
1507	  NUMA awareness to the kernel.
1508
1509	  For 64-bit this is recommended if the system is Intel Core i7
1510	  (or later), AMD Opteron, or EM64T NUMA.
1511
1512	  Otherwise, you should say N.
1513
1514config AMD_NUMA
1515	def_bool y
1516	prompt "Old style AMD Opteron NUMA detection"
1517	depends on X86_64 && NUMA && PCI
1518	help
1519	  Enable AMD NUMA node topology detection.  You should say Y here if
1520	  you have a multi processor AMD system. This uses an old method to
1521	  read the NUMA configuration directly from the builtin Northbridge
1522	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1523	  which also takes priority if both are compiled in.
1524
1525config X86_64_ACPI_NUMA
1526	def_bool y
1527	prompt "ACPI NUMA detection"
1528	depends on X86_64 && NUMA && ACPI && PCI
1529	select ACPI_NUMA
1530	help
1531	  Enable ACPI SRAT based node topology detection.
1532
1533config NODES_SHIFT
1534	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1535	range 1 10
1536	default "10" if MAXSMP
1537	default "6" if X86_64
1538	default "3"
1539	depends on NUMA
1540	help
1541	  Specify the maximum number of NUMA Nodes available on the target
1542	  system.  Increases memory reserved to accommodate various tables.
1543
1544config ARCH_FLATMEM_ENABLE
1545	def_bool y
1546	depends on X86_32 && !NUMA
1547
1548config ARCH_SPARSEMEM_ENABLE
1549	def_bool y
1550	select SPARSEMEM_STATIC if X86_32
1551	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1552	select SPARSEMEM_VMEMMAP if X86_64
1553
1554config ARCH_SPARSEMEM_DEFAULT
1555	def_bool X86_64 || (NUMA && X86_32)
1556
1557config ARCH_SELECT_MEMORY_MODEL
1558	def_bool y
1559	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1560
1561config ARCH_MEMORY_PROBE
1562	bool "Enable sysfs memory/probe interface"
1563	depends on MEMORY_HOTPLUG
1564	help
1565	  This option enables a sysfs memory/probe interface for testing.
1566	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1567	  If you are unsure how to answer this question, answer N.
1568
1569config ARCH_PROC_KCORE_TEXT
1570	def_bool y
1571	depends on X86_64 && PROC_KCORE
1572
1573config ILLEGAL_POINTER_VALUE
1574	hex
1575	default 0 if X86_32
1576	default 0xdead000000000000 if X86_64
1577
1578config X86_PMEM_LEGACY_DEVICE
1579	bool
1580
1581config X86_PMEM_LEGACY
1582	tristate "Support non-standard NVDIMMs and ADR protected memory"
1583	depends on PHYS_ADDR_T_64BIT
1584	depends on BLK_DEV
1585	select X86_PMEM_LEGACY_DEVICE
1586	select NUMA_KEEP_MEMINFO if NUMA
1587	select LIBNVDIMM
1588	help
1589	  Treat memory marked using the non-standard e820 type of 12 as used
1590	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1591	  The kernel will offer these regions to the 'pmem' driver so
1592	  they can be used for persistent storage.
1593
1594	  Say Y if unsure.
1595
1596config X86_CHECK_BIOS_CORRUPTION
1597	bool "Check for low memory corruption"
1598	help
1599	  Periodically check for memory corruption in low memory, which
1600	  is suspected to be caused by BIOS.  Even when enabled in the
1601	  configuration, it is disabled at runtime.  Enable it by
1602	  setting "memory_corruption_check=1" on the kernel command
1603	  line.  By default it scans the low 64k of memory every 60
1604	  seconds; see the memory_corruption_check_size and
1605	  memory_corruption_check_period parameters in
1606	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1607
1608	  When enabled with the default parameters, this option has
1609	  almost no overhead, as it reserves a relatively small amount
1610	  of memory and scans it infrequently.  It both detects corruption
1611	  and prevents it from affecting the running system.
1612
1613	  It is, however, intended as a diagnostic tool; if repeatable
1614	  BIOS-originated corruption always affects the same memory,
1615	  you can use memmap= to prevent the kernel from using that
1616	  memory.
1617
1618config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1619	bool "Set the default setting of memory_corruption_check"
1620	depends on X86_CHECK_BIOS_CORRUPTION
1621	default y
1622	help
1623	  Set whether the default state of memory_corruption_check is
1624	  on or off.
1625
1626config MATH_EMULATION
1627	bool
1628	depends on MODIFY_LDT_SYSCALL
1629	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1630	help
1631	  Linux can emulate a math coprocessor (used for floating point
1632	  operations) if you don't have one. 486DX and Pentium processors have
1633	  a math coprocessor built in, 486SX and 386 do not, unless you added
1634	  a 487DX or 387, respectively. (The messages during boot time can
1635	  give you some hints here ["man dmesg"].) Everyone needs either a
1636	  coprocessor or this emulation.
1637
1638	  If you don't have a math coprocessor, you need to say Y here; if you
1639	  say Y here even though you have a coprocessor, the coprocessor will
1640	  be used nevertheless. (This behavior can be changed with the kernel
1641	  command line option "no387", which comes handy if your coprocessor
1642	  is broken. Try "man bootparam" or see the documentation of your boot
1643	  loader (lilo or loadlin) about how to pass options to the kernel at
1644	  boot time.) This means that it is a good idea to say Y here if you
1645	  intend to use this kernel on different machines.
1646
1647	  More information about the internals of the Linux math coprocessor
1648	  emulation can be found in <file:arch/x86/math-emu/README>.
1649
1650	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1651	  kernel, it won't hurt.
1652
1653config MTRR
1654	def_bool y
1655	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1656	help
1657	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1658	  the Memory Type Range Registers (MTRRs) may be used to control
1659	  processor access to memory ranges. This is most useful if you have
1660	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1661	  allows bus write transfers to be combined into a larger transfer
1662	  before bursting over the PCI/AGP bus. This can increase performance
1663	  of image write operations 2.5 times or more. Saying Y here creates a
1664	  /proc/mtrr file which may be used to manipulate your processor's
1665	  MTRRs. Typically the X server should use this.
1666
1667	  This code has a reasonably generic interface so that similar
1668	  control registers on other processors can be easily supported
1669	  as well:
1670
1671	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1672	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1673	  these, the ARRs are used to emulate the MTRRs.
1674	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1675	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1676	  write-combining. All of these processors are supported by this code
1677	  and it makes sense to say Y here if you have one of them.
1678
1679	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1680	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1681	  can lead to all sorts of problems, so it's good to say Y here.
1682
1683	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1684	  just add about 9 KB to your kernel.
1685
1686	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1687
1688config MTRR_SANITIZER
1689	def_bool y
1690	prompt "MTRR cleanup support"
1691	depends on MTRR
1692	help
1693	  Convert MTRR layout from continuous to discrete, so X drivers can
1694	  add writeback entries.
1695
1696	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1697	  The largest mtrr entry size for a continuous block can be set with
1698	  mtrr_chunk_size.
1699
1700	  If unsure, say Y.
1701
1702config MTRR_SANITIZER_ENABLE_DEFAULT
1703	int "MTRR cleanup enable value (0-1)"
1704	range 0 1
1705	default "0"
1706	depends on MTRR_SANITIZER
1707	help
1708	  Enable mtrr cleanup default value
1709
1710config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1711	int "MTRR cleanup spare reg num (0-7)"
1712	range 0 7
1713	default "1"
1714	depends on MTRR_SANITIZER
1715	help
1716	  mtrr cleanup spare entries default, it can be changed via
1717	  mtrr_spare_reg_nr=N on the kernel command line.
1718
1719config X86_PAT
1720	def_bool y
1721	prompt "x86 PAT support" if EXPERT
1722	depends on MTRR
1723	select ARCH_USES_PG_ARCH_2
1724	help
1725	  Use PAT attributes to setup page level cache control.
1726
1727	  PATs are the modern equivalents of MTRRs and are much more
1728	  flexible than MTRRs.
1729
1730	  Say N here if you see bootup problems (boot crash, boot hang,
1731	  spontaneous reboots) or a non-working video driver.
1732
1733	  If unsure, say Y.
1734
1735config X86_UMIP
1736	def_bool y
1737	prompt "User Mode Instruction Prevention" if EXPERT
1738	help
1739	  User Mode Instruction Prevention (UMIP) is a security feature in
1740	  some x86 processors. If enabled, a general protection fault is
1741	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1742	  executed in user mode. These instructions unnecessarily expose
1743	  information about the hardware state.
1744
1745	  The vast majority of applications do not use these instructions.
1746	  For the very few that do, software emulation is provided in
1747	  specific cases in protected and virtual-8086 modes. Emulated
1748	  results are dummy.
1749
1750config CC_HAS_IBT
1751	# GCC >= 9 and binutils >= 2.29
1752	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1753	# Clang/LLVM >= 14
1754	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1755	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1756	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1757		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1758		  $(as-instr,endbr64)
1759
1760config X86_CET
1761	def_bool n
1762	help
1763	  CET features configured (Shadow stack or IBT)
1764
1765config X86_KERNEL_IBT
1766	prompt "Indirect Branch Tracking"
1767	def_bool y
1768	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1769	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1770	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1771	select OBJTOOL
1772	select X86_CET
1773	help
1774	  Build the kernel with support for Indirect Branch Tracking, a
1775	  hardware support course-grain forward-edge Control Flow Integrity
1776	  protection. It enforces that all indirect calls must land on
1777	  an ENDBR instruction, as such, the compiler will instrument the
1778	  code with them to make this happen.
1779
1780	  In addition to building the kernel with IBT, seal all functions that
1781	  are not indirect call targets, avoiding them ever becoming one.
1782
1783	  This requires LTO like objtool runs and will slow down the build. It
1784	  does significantly reduce the number of ENDBR instructions in the
1785	  kernel image.
1786
1787config X86_INTEL_MEMORY_PROTECTION_KEYS
1788	prompt "Memory Protection Keys"
1789	def_bool y
1790	# Note: only available in 64-bit mode
1791	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1792	select ARCH_USES_HIGH_VMA_FLAGS
1793	select ARCH_HAS_PKEYS
1794	help
1795	  Memory Protection Keys provides a mechanism for enforcing
1796	  page-based protections, but without requiring modification of the
1797	  page tables when an application changes protection domains.
1798
1799	  For details, see Documentation/core-api/protection-keys.rst
1800
1801	  If unsure, say y.
1802
1803config ARCH_PKEY_BITS
1804	int
1805	default 4
1806
1807choice
1808	prompt "TSX enable mode"
1809	depends on CPU_SUP_INTEL
1810	default X86_INTEL_TSX_MODE_OFF
1811	help
1812	  Intel's TSX (Transactional Synchronization Extensions) feature
1813	  allows to optimize locking protocols through lock elision which
1814	  can lead to a noticeable performance boost.
1815
1816	  On the other hand it has been shown that TSX can be exploited
1817	  to form side channel attacks (e.g. TAA) and chances are there
1818	  will be more of those attacks discovered in the future.
1819
1820	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1821	  might override this decision by tsx=on the command line parameter.
1822	  Even with TSX enabled, the kernel will attempt to enable the best
1823	  possible TAA mitigation setting depending on the microcode available
1824	  for the particular machine.
1825
1826	  This option allows to set the default tsx mode between tsx=on, =off
1827	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1828	  details.
1829
1830	  Say off if not sure, auto if TSX is in use but it should be used on safe
1831	  platforms or on if TSX is in use and the security aspect of tsx is not
1832	  relevant.
1833
1834config X86_INTEL_TSX_MODE_OFF
1835	bool "off"
1836	help
1837	  TSX is disabled if possible - equals to tsx=off command line parameter.
1838
1839config X86_INTEL_TSX_MODE_ON
1840	bool "on"
1841	help
1842	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1843	  line parameter.
1844
1845config X86_INTEL_TSX_MODE_AUTO
1846	bool "auto"
1847	help
1848	  TSX is enabled on TSX capable HW that is believed to be safe against
1849	  side channel attacks- equals the tsx=auto command line parameter.
1850endchoice
1851
1852config X86_SGX
1853	bool "Software Guard eXtensions (SGX)"
1854	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1855	select CRYPTO_LIB_SHA256
1856	select MMU_NOTIFIER
1857	select NUMA_KEEP_MEMINFO if NUMA
1858	select XARRAY_MULTI
1859	help
1860	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1861	  that can be used by applications to set aside private regions of code
1862	  and data, referred to as enclaves. An enclave's private memory can
1863	  only be accessed by code running within the enclave. Accesses from
1864	  outside the enclave, including other enclaves, are disallowed by
1865	  hardware.
1866
1867	  If unsure, say N.
1868
1869config X86_USER_SHADOW_STACK
1870	bool "X86 userspace shadow stack"
1871	depends on AS_WRUSS
1872	depends on X86_64
1873	select ARCH_USES_HIGH_VMA_FLAGS
1874	select ARCH_HAS_USER_SHADOW_STACK
1875	select X86_CET
1876	help
1877	  Shadow stack protection is a hardware feature that detects function
1878	  return address corruption.  This helps mitigate ROP attacks.
1879	  Applications must be enabled to use it, and old userspace does not
1880	  get protection "for free".
1881
1882	  CPUs supporting shadow stacks were first released in 2020.
1883
1884	  See Documentation/arch/x86/shstk.rst for more information.
1885
1886	  If unsure, say N.
1887
1888config INTEL_TDX_HOST
1889	bool "Intel Trust Domain Extensions (TDX) host support"
1890	depends on CPU_SUP_INTEL
1891	depends on X86_64
1892	depends on KVM_INTEL
1893	depends on X86_X2APIC
1894	select ARCH_KEEP_MEMBLOCK
1895	depends on CONTIG_ALLOC
1896	depends on !KEXEC_CORE
1897	depends on X86_MCE
1898	help
1899	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1900	  host and certain physical attacks.  This option enables necessary TDX
1901	  support in the host kernel to run confidential VMs.
1902
1903	  If unsure, say N.
1904
1905config EFI
1906	bool "EFI runtime service support"
1907	depends on ACPI
1908	select UCS2_STRING
1909	select EFI_RUNTIME_WRAPPERS
1910	select ARCH_USE_MEMREMAP_PROT
1911	select EFI_RUNTIME_MAP if KEXEC_CORE
1912	help
1913	  This enables the kernel to use EFI runtime services that are
1914	  available (such as the EFI variable services).
1915
1916	  This option is only useful on systems that have EFI firmware.
1917	  In addition, you should use the latest ELILO loader available
1918	  at <http://elilo.sourceforge.net> in order to take advantage
1919	  of EFI runtime services. However, even with this option, the
1920	  resultant kernel should continue to boot on existing non-EFI
1921	  platforms.
1922
1923config EFI_STUB
1924	bool "EFI stub support"
1925	depends on EFI
1926	select RELOCATABLE
1927	help
1928	  This kernel feature allows a bzImage to be loaded directly
1929	  by EFI firmware without the use of a bootloader.
1930
1931	  See Documentation/admin-guide/efi-stub.rst for more information.
1932
1933config EFI_HANDOVER_PROTOCOL
1934	bool "EFI handover protocol (DEPRECATED)"
1935	depends on EFI_STUB
1936	default y
1937	help
1938	  Select this in order to include support for the deprecated EFI
1939	  handover protocol, which defines alternative entry points into the
1940	  EFI stub.  This is a practice that has no basis in the UEFI
1941	  specification, and requires a priori knowledge on the part of the
1942	  bootloader about Linux/x86 specific ways of passing the command line
1943	  and initrd, and where in memory those assets may be loaded.
1944
1945	  If in doubt, say Y. Even though the corresponding support is not
1946	  present in upstream GRUB or other bootloaders, most distros build
1947	  GRUB with numerous downstream patches applied, and may rely on the
1948	  handover protocol as as result.
1949
1950config EFI_MIXED
1951	bool "EFI mixed-mode support"
1952	depends on EFI_STUB && X86_64
1953	help
1954	  Enabling this feature allows a 64-bit kernel to be booted
1955	  on a 32-bit firmware, provided that your CPU supports 64-bit
1956	  mode.
1957
1958	  Note that it is not possible to boot a mixed-mode enabled
1959	  kernel via the EFI boot stub - a bootloader that supports
1960	  the EFI handover protocol must be used.
1961
1962	  If unsure, say N.
1963
1964config EFI_RUNTIME_MAP
1965	bool "Export EFI runtime maps to sysfs" if EXPERT
1966	depends on EFI
1967	help
1968	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1969	  That memory map is required by the 2nd kernel to set up EFI virtual
1970	  mappings after kexec, but can also be used for debugging purposes.
1971
1972	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1973
1974source "kernel/Kconfig.hz"
1975
1976config ARCH_SUPPORTS_KEXEC
1977	def_bool y
1978
1979config ARCH_SUPPORTS_KEXEC_FILE
1980	def_bool X86_64
1981
1982config ARCH_SELECTS_KEXEC_FILE
1983	def_bool y
1984	depends on KEXEC_FILE
1985	select HAVE_IMA_KEXEC if IMA
1986
1987config ARCH_SUPPORTS_KEXEC_PURGATORY
1988	def_bool y
1989
1990config ARCH_SUPPORTS_KEXEC_SIG
1991	def_bool y
1992
1993config ARCH_SUPPORTS_KEXEC_SIG_FORCE
1994	def_bool y
1995
1996config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
1997	def_bool y
1998
1999config ARCH_SUPPORTS_KEXEC_JUMP
2000	def_bool y
2001
2002config ARCH_SUPPORTS_KEXEC_HANDOVER
2003	def_bool X86_64
2004
2005config ARCH_SUPPORTS_CRASH_DUMP
2006	def_bool X86_64 || (X86_32 && HIGHMEM)
2007
2008config ARCH_DEFAULT_CRASH_DUMP
2009	def_bool y
2010
2011config ARCH_SUPPORTS_CRASH_HOTPLUG
2012	def_bool y
2013
2014config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2015	def_bool CRASH_RESERVE
2016
2017config PHYSICAL_START
2018	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2019	default "0x1000000"
2020	help
2021	  This gives the physical address where the kernel is loaded.
2022
2023	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2024	  will decompress itself to above physical address and run from there.
2025	  Otherwise, bzImage will run from the address where it has been loaded
2026	  by the boot loader. The only exception is if it is loaded below the
2027	  above physical address, in which case it will relocate itself there.
2028
2029	  In normal kdump cases one does not have to set/change this option
2030	  as now bzImage can be compiled as a completely relocatable image
2031	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2032	  address. This option is mainly useful for the folks who don't want
2033	  to use a bzImage for capturing the crash dump and want to use a
2034	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2035	  to be specifically compiled to run from a specific memory area
2036	  (normally a reserved region) and this option comes handy.
2037
2038	  So if you are using bzImage for capturing the crash dump,
2039	  leave the value here unchanged to 0x1000000 and set
2040	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2041	  for capturing the crash dump change this value to start of
2042	  the reserved region.  In other words, it can be set based on
2043	  the "X" value as specified in the "crashkernel=YM@XM"
2044	  command line boot parameter passed to the panic-ed
2045	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2046	  for more details about crash dumps.
2047
2048	  Usage of bzImage for capturing the crash dump is recommended as
2049	  one does not have to build two kernels. Same kernel can be used
2050	  as production kernel and capture kernel. Above option should have
2051	  gone away after relocatable bzImage support is introduced. But it
2052	  is present because there are users out there who continue to use
2053	  vmlinux for dump capture. This option should go away down the
2054	  line.
2055
2056	  Don't change this unless you know what you are doing.
2057
2058config RELOCATABLE
2059	bool "Build a relocatable kernel"
2060	default y
2061	help
2062	  This builds a kernel image that retains relocation information
2063	  so it can be loaded someplace besides the default 1MB.
2064	  The relocations tend to make the kernel binary about 10% larger,
2065	  but are discarded at runtime.
2066
2067	  One use is for the kexec on panic case where the recovery kernel
2068	  must live at a different physical address than the primary
2069	  kernel.
2070
2071	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2072	  it has been loaded at and the compile time physical address
2073	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2074
2075config RANDOMIZE_BASE
2076	bool "Randomize the address of the kernel image (KASLR)"
2077	depends on RELOCATABLE
2078	default y
2079	help
2080	  In support of Kernel Address Space Layout Randomization (KASLR),
2081	  this randomizes the physical address at which the kernel image
2082	  is decompressed and the virtual address where the kernel
2083	  image is mapped, as a security feature that deters exploit
2084	  attempts relying on knowledge of the location of kernel
2085	  code internals.
2086
2087	  On 64-bit, the kernel physical and virtual addresses are
2088	  randomized separately. The physical address will be anywhere
2089	  between 16MB and the top of physical memory (up to 64TB). The
2090	  virtual address will be randomized from 16MB up to 1GB (9 bits
2091	  of entropy). Note that this also reduces the memory space
2092	  available to kernel modules from 1.5GB to 1GB.
2093
2094	  On 32-bit, the kernel physical and virtual addresses are
2095	  randomized together. They will be randomized from 16MB up to
2096	  512MB (8 bits of entropy).
2097
2098	  Entropy is generated using the RDRAND instruction if it is
2099	  supported. If RDTSC is supported, its value is mixed into
2100	  the entropy pool as well. If neither RDRAND nor RDTSC are
2101	  supported, then entropy is read from the i8254 timer. The
2102	  usable entropy is limited by the kernel being built using
2103	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2104	  minimum of 2MB. As a result, only 10 bits of entropy are
2105	  theoretically possible, but the implementations are further
2106	  limited due to memory layouts.
2107
2108	  If unsure, say Y.
2109
2110# Relocation on x86 needs some additional build support
2111config X86_NEED_RELOCS
2112	def_bool y
2113	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2114	select ARCH_VMLINUX_NEEDS_RELOCS
2115
2116config PHYSICAL_ALIGN
2117	hex "Alignment value to which kernel should be aligned"
2118	default "0x200000"
2119	range 0x2000 0x1000000 if X86_32
2120	range 0x200000 0x1000000 if X86_64
2121	help
2122	  This value puts the alignment restrictions on physical address
2123	  where kernel is loaded and run from. Kernel is compiled for an
2124	  address which meets above alignment restriction.
2125
2126	  If bootloader loads the kernel at a non-aligned address and
2127	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2128	  address aligned to above value and run from there.
2129
2130	  If bootloader loads the kernel at a non-aligned address and
2131	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2132	  load address and decompress itself to the address it has been
2133	  compiled for and run from there. The address for which kernel is
2134	  compiled already meets above alignment restrictions. Hence the
2135	  end result is that kernel runs from a physical address meeting
2136	  above alignment restrictions.
2137
2138	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2139	  this value must be a multiple of 0x200000.
2140
2141	  Don't change this unless you know what you are doing.
2142
2143config RANDOMIZE_MEMORY
2144	bool "Randomize the kernel memory sections"
2145	depends on X86_64
2146	depends on RANDOMIZE_BASE
2147	default RANDOMIZE_BASE
2148	help
2149	  Randomizes the base virtual address of kernel memory sections
2150	  (physical memory mapping, vmalloc & vmemmap). This security feature
2151	  makes exploits relying on predictable memory locations less reliable.
2152
2153	  The order of allocations remains unchanged. Entropy is generated in
2154	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2155	  configuration have in average 30,000 different possible virtual
2156	  addresses for each memory section.
2157
2158	  If unsure, say Y.
2159
2160config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2161	hex "Physical memory mapping padding" if EXPERT
2162	depends on RANDOMIZE_MEMORY
2163	default "0xa" if MEMORY_HOTPLUG
2164	default "0x0"
2165	range 0x1 0x40 if MEMORY_HOTPLUG
2166	range 0x0 0x40
2167	help
2168	  Define the padding in terabytes added to the existing physical
2169	  memory size during kernel memory randomization. It is useful
2170	  for memory hotplug support but reduces the entropy available for
2171	  address randomization.
2172
2173	  If unsure, leave at the default value.
2174
2175config ADDRESS_MASKING
2176	bool "Linear Address Masking support"
2177	depends on X86_64
2178	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2179	help
2180	  Linear Address Masking (LAM) modifies the checking that is applied
2181	  to 64-bit linear addresses, allowing software to use of the
2182	  untranslated address bits for metadata.
2183
2184	  The capability can be used for efficient address sanitizers (ASAN)
2185	  implementation and for optimizations in JITs.
2186
2187config HOTPLUG_CPU
2188	def_bool y
2189	depends on SMP
2190
2191config COMPAT_VDSO
2192	def_bool n
2193	prompt "Workaround for glibc 2.3.2 / 2.3.3 (released in year 2003/2004)"
2194	depends on COMPAT_32
2195	help
2196	  Certain buggy versions of glibc will crash if they are
2197	  presented with a 32-bit vDSO that is not mapped at the address
2198	  indicated in its segment table.
2199
2200	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2201	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2202	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2203	  the only released version with the bug, but OpenSUSE 9
2204	  contains a buggy "glibc 2.3.2".
2205
2206	  The symptom of the bug is that everything crashes on startup, saying:
2207	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2208
2209	  Saying Y here changes the default value of the vdso32 boot
2210	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2211	  This works around the glibc bug but hurts performance.
2212
2213	  If unsure, say N: if you are compiling your own kernel, you
2214	  are unlikely to be using a buggy version of glibc.
2215
2216choice
2217	prompt "vsyscall table for legacy applications"
2218	depends on X86_64
2219	default LEGACY_VSYSCALL_XONLY
2220	help
2221	  Legacy user code that does not know how to find the vDSO expects
2222	  to be able to issue three syscalls by calling fixed addresses in
2223	  kernel space. Since this location is not randomized with ASLR,
2224	  it can be used to assist security vulnerability exploitation.
2225
2226	  This setting can be changed at boot time via the kernel command
2227	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2228	  is deprecated and can only be enabled using the kernel command
2229	  line.
2230
2231	  On a system with recent enough glibc (2.14 or newer) and no
2232	  static binaries, you can say None without a performance penalty
2233	  to improve security.
2234
2235	  If unsure, select "Emulate execution only".
2236
2237	config LEGACY_VSYSCALL_XONLY
2238		bool "Emulate execution only"
2239		help
2240		  The kernel traps and emulates calls into the fixed vsyscall
2241		  address mapping and does not allow reads.  This
2242		  configuration is recommended when userspace might use the
2243		  legacy vsyscall area but support for legacy binary
2244		  instrumentation of legacy code is not needed.  It mitigates
2245		  certain uses of the vsyscall area as an ASLR-bypassing
2246		  buffer.
2247
2248	config LEGACY_VSYSCALL_NONE
2249		bool "None"
2250		help
2251		  There will be no vsyscall mapping at all. This will
2252		  eliminate any risk of ASLR bypass due to the vsyscall
2253		  fixed address mapping. Attempts to use the vsyscalls
2254		  will be reported to dmesg, so that either old or
2255		  malicious userspace programs can be identified.
2256
2257endchoice
2258
2259config CMDLINE_BOOL
2260	bool "Built-in kernel command line"
2261	help
2262	  Allow for specifying boot arguments to the kernel at
2263	  build time.  On some systems (e.g. embedded ones), it is
2264	  necessary or convenient to provide some or all of the
2265	  kernel boot arguments with the kernel itself (that is,
2266	  to not rely on the boot loader to provide them.)
2267
2268	  To compile command line arguments into the kernel,
2269	  set this option to 'Y', then fill in the
2270	  boot arguments in CONFIG_CMDLINE.
2271
2272	  Systems with fully functional boot loaders (i.e. non-embedded)
2273	  should leave this option set to 'N'.
2274
2275config CMDLINE
2276	string "Built-in kernel command string"
2277	depends on CMDLINE_BOOL
2278	default ""
2279	help
2280	  Enter arguments here that should be compiled into the kernel
2281	  image and used at boot time.  If the boot loader provides a
2282	  command line at boot time, it is appended to this string to
2283	  form the full kernel command line, when the system boots.
2284
2285	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2286	  change this behavior.
2287
2288	  In most cases, the command line (whether built-in or provided
2289	  by the boot loader) should specify the device for the root
2290	  file system.
2291
2292config CMDLINE_OVERRIDE
2293	bool "Built-in command line overrides boot loader arguments"
2294	depends on CMDLINE_BOOL && CMDLINE != ""
2295	help
2296	  Set this option to 'Y' to have the kernel ignore the boot loader
2297	  command line, and use ONLY the built-in command line.
2298
2299	  This is used to work around broken boot loaders.  This should
2300	  be set to 'N' under normal conditions.
2301
2302config MODIFY_LDT_SYSCALL
2303	bool "Enable the LDT (local descriptor table)" if EXPERT
2304	default y
2305	help
2306	  Linux can allow user programs to install a per-process x86
2307	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2308	  call.  This is required to run 16-bit or segmented code such as
2309	  DOSEMU or some Wine programs.  It is also used by some very old
2310	  threading libraries.
2311
2312	  Enabling this feature adds a small amount of overhead to
2313	  context switches and increases the low-level kernel attack
2314	  surface.  Disabling it removes the modify_ldt(2) system call.
2315
2316	  Saying 'N' here may make sense for embedded or server kernels.
2317
2318config STRICT_SIGALTSTACK_SIZE
2319	bool "Enforce strict size checking for sigaltstack"
2320	depends on DYNAMIC_SIGFRAME
2321	help
2322	  For historical reasons MINSIGSTKSZ is a constant which became
2323	  already too small with AVX512 support. Add a mechanism to
2324	  enforce strict checking of the sigaltstack size against the
2325	  real size of the FPU frame. This option enables the check
2326	  by default. It can also be controlled via the kernel command
2327	  line option 'strict_sas_size' independent of this config
2328	  switch. Enabling it might break existing applications which
2329	  allocate a too small sigaltstack but 'work' because they
2330	  never get a signal delivered.
2331
2332	  Say 'N' unless you want to really enforce this check.
2333
2334config CFI_AUTO_DEFAULT
2335	bool "Attempt to use FineIBT by default at boot time"
2336	depends on FINEIBT
2337	depends on !RUST || RUSTC_VERSION >= 108800
2338	default y
2339	help
2340	  Attempt to use FineIBT by default at boot time. If enabled,
2341	  this is the same as booting with "cfi=auto". If disabled,
2342	  this is the same as booting with "cfi=kcfi".
2343
2344source "kernel/livepatch/Kconfig"
2345
2346config X86_BUS_LOCK_DETECT
2347	bool "Split Lock Detect and Bus Lock Detect support"
2348	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2349	default y
2350	help
2351	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2352	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2353
2354endmenu
2355
2356config CC_HAS_NAMED_AS
2357	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2358	depends on CC_IS_GCC
2359
2360#
2361# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2362# are incompatible with named address spaces with GCC < 13.3
2363# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2364#
2365
2366config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2367	def_bool y
2368	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2369	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2370
2371config USE_X86_SEG_SUPPORT
2372	def_bool CC_HAS_NAMED_AS
2373	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2374
2375config CC_HAS_SLS
2376	def_bool $(cc-option,-mharden-sls=all)
2377
2378config CC_HAS_RETURN_THUNK
2379	def_bool $(cc-option,-mfunction-return=thunk-extern)
2380
2381config CC_HAS_ENTRY_PADDING
2382	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2383
2384config CC_HAS_KCFI_ARITY
2385	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2386	depends on CC_IS_CLANG && !RUST
2387
2388config FUNCTION_PADDING_CFI
2389	int
2390	default 59 if FUNCTION_ALIGNMENT_64B
2391	default 27 if FUNCTION_ALIGNMENT_32B
2392	default 11 if FUNCTION_ALIGNMENT_16B
2393	default  3 if FUNCTION_ALIGNMENT_8B
2394	default  0
2395
2396# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2397# except Kconfig can't do arithmetic :/
2398config FUNCTION_PADDING_BYTES
2399	int
2400	default FUNCTION_PADDING_CFI if CFI_CLANG
2401	default FUNCTION_ALIGNMENT
2402
2403config CALL_PADDING
2404	def_bool n
2405	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2406	select FUNCTION_ALIGNMENT_16B
2407
2408config FINEIBT
2409	def_bool y
2410	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
2411	select CALL_PADDING
2412
2413config FINEIBT_BHI
2414	def_bool y
2415	depends on FINEIBT && CC_HAS_KCFI_ARITY
2416
2417config HAVE_CALL_THUNKS
2418	def_bool y
2419	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2420
2421config CALL_THUNKS
2422	def_bool n
2423	select CALL_PADDING
2424
2425config PREFIX_SYMBOLS
2426	def_bool y
2427	depends on CALL_PADDING && !CFI_CLANG
2428
2429menuconfig CPU_MITIGATIONS
2430	bool "Mitigations for CPU vulnerabilities"
2431	default y
2432	help
2433	  Say Y here to enable options which enable mitigations for hardware
2434	  vulnerabilities (usually related to speculative execution).
2435	  Mitigations can be disabled or restricted to SMT systems at runtime
2436	  via the "mitigations" kernel parameter.
2437
2438	  If you say N, all mitigations will be disabled.  This CANNOT be
2439	  overridden at runtime.
2440
2441	  Say 'Y', unless you really know what you are doing.
2442
2443if CPU_MITIGATIONS
2444
2445config MITIGATION_PAGE_TABLE_ISOLATION
2446	bool "Remove the kernel mapping in user mode"
2447	default y
2448	depends on (X86_64 || X86_PAE)
2449	help
2450	  This feature reduces the number of hardware side channels by
2451	  ensuring that the majority of kernel addresses are not mapped
2452	  into userspace.
2453
2454	  See Documentation/arch/x86/pti.rst for more details.
2455
2456config MITIGATION_RETPOLINE
2457	bool "Avoid speculative indirect branches in kernel"
2458	select OBJTOOL if HAVE_OBJTOOL
2459	default y
2460	help
2461	  Compile kernel with the retpoline compiler options to guard against
2462	  kernel-to-user data leaks by avoiding speculative indirect
2463	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2464	  support for full protection. The kernel may run slower.
2465
2466config MITIGATION_RETHUNK
2467	bool "Enable return-thunks"
2468	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2469	select OBJTOOL if HAVE_OBJTOOL
2470	default y if X86_64
2471	help
2472	  Compile the kernel with the return-thunks compiler option to guard
2473	  against kernel-to-user data leaks by avoiding return speculation.
2474	  Requires a compiler with -mfunction-return=thunk-extern
2475	  support for full protection. The kernel may run slower.
2476
2477config MITIGATION_UNRET_ENTRY
2478	bool "Enable UNRET on kernel entry"
2479	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2480	default y
2481	help
2482	  Compile the kernel with support for the retbleed=unret mitigation.
2483
2484config MITIGATION_CALL_DEPTH_TRACKING
2485	bool "Mitigate RSB underflow with call depth tracking"
2486	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2487	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2488	select CALL_THUNKS
2489	default y
2490	help
2491	  Compile the kernel with call depth tracking to mitigate the Intel
2492	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2493	  by default and needs to be enabled on the kernel command line via the
2494	  retbleed=stuff option. For non-affected systems the overhead of this
2495	  option is marginal as the call depth tracking is using run-time
2496	  generated call thunks in a compiler generated padding area and call
2497	  patching. This increases text size by ~5%. For non affected systems
2498	  this space is unused. On affected SKL systems this results in a
2499	  significant performance gain over the IBRS mitigation.
2500
2501config CALL_THUNKS_DEBUG
2502	bool "Enable call thunks and call depth tracking debugging"
2503	depends on MITIGATION_CALL_DEPTH_TRACKING
2504	select FUNCTION_ALIGNMENT_32B
2505	default n
2506	help
2507	  Enable call/ret counters for imbalance detection and build in
2508	  a noisy dmesg about callthunks generation and call patching for
2509	  trouble shooting. The debug prints need to be enabled on the
2510	  kernel command line with 'debug-callthunks'.
2511	  Only enable this when you are debugging call thunks as this
2512	  creates a noticeable runtime overhead. If unsure say N.
2513
2514config MITIGATION_IBPB_ENTRY
2515	bool "Enable IBPB on kernel entry"
2516	depends on CPU_SUP_AMD && X86_64
2517	default y
2518	help
2519	  Compile the kernel with support for the retbleed=ibpb and
2520	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2521
2522config MITIGATION_IBRS_ENTRY
2523	bool "Enable IBRS on kernel entry"
2524	depends on CPU_SUP_INTEL && X86_64
2525	default y
2526	help
2527	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2528	  This mitigates both spectre_v2 and retbleed at great cost to
2529	  performance.
2530
2531config MITIGATION_SRSO
2532	bool "Mitigate speculative RAS overflow on AMD"
2533	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2534	default y
2535	help
2536	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2537
2538config MITIGATION_SLS
2539	bool "Mitigate Straight-Line-Speculation"
2540	depends on CC_HAS_SLS && X86_64
2541	select OBJTOOL if HAVE_OBJTOOL
2542	default n
2543	help
2544	  Compile the kernel with straight-line-speculation options to guard
2545	  against straight line speculation. The kernel image might be slightly
2546	  larger.
2547
2548config MITIGATION_GDS
2549	bool "Mitigate Gather Data Sampling"
2550	depends on CPU_SUP_INTEL
2551	default y
2552	help
2553	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2554	  vulnerability which allows unprivileged speculative access to data
2555	  which was previously stored in vector registers. The attacker uses gather
2556	  instructions to infer the stale vector register data.
2557
2558config MITIGATION_RFDS
2559	bool "RFDS Mitigation"
2560	depends on CPU_SUP_INTEL
2561	default y
2562	help
2563	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2564	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2565	  allows unprivileged speculative access to stale data previously
2566	  stored in floating point, vector and integer registers.
2567	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2568
2569config MITIGATION_SPECTRE_BHI
2570	bool "Mitigate Spectre-BHB (Branch History Injection)"
2571	depends on CPU_SUP_INTEL
2572	default y
2573	help
2574	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2575	  where the branch history buffer is poisoned to speculatively steer
2576	  indirect branches.
2577	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2578
2579config MITIGATION_MDS
2580	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2581	depends on CPU_SUP_INTEL
2582	default y
2583	help
2584	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2585	  a hardware vulnerability which allows unprivileged speculative access
2586	  to data which is available in various CPU internal buffers.
2587	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2588
2589config MITIGATION_TAA
2590	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2591	depends on CPU_SUP_INTEL
2592	default y
2593	help
2594	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2595	  vulnerability that allows unprivileged speculative access to data
2596	  which is available in various CPU internal buffers by using
2597	  asynchronous aborts within an Intel TSX transactional region.
2598	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2599
2600config MITIGATION_MMIO_STALE_DATA
2601	bool "Mitigate MMIO Stale Data hardware bug"
2602	depends on CPU_SUP_INTEL
2603	default y
2604	help
2605	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2606	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2607	  vulnerabilities that can expose data. The vulnerabilities require the
2608	  attacker to have access to MMIO.
2609	  See also
2610	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2611
2612config MITIGATION_L1TF
2613	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2614	depends on CPU_SUP_INTEL
2615	default y
2616	help
2617	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2618	  hardware vulnerability which allows unprivileged speculative access to data
2619	  available in the Level 1 Data Cache.
2620	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2621
2622config MITIGATION_RETBLEED
2623	bool "Mitigate RETBleed hardware bug"
2624	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2625	default y
2626	help
2627	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2628	  with Return Instructions) vulnerability.  RETBleed is a speculative
2629	  execution attack which takes advantage of microarchitectural behavior
2630	  in many modern microprocessors, similar to Spectre v2. An
2631	  unprivileged attacker can use these flaws to bypass conventional
2632	  memory security restrictions to gain read access to privileged memory
2633	  that would otherwise be inaccessible.
2634
2635config MITIGATION_SPECTRE_V1
2636	bool "Mitigate SPECTRE V1 hardware bug"
2637	default y
2638	help
2639	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2640	  class of side channel attacks that takes advantage of speculative
2641	  execution that bypasses conditional branch instructions used for
2642	  memory access bounds check.
2643	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2644
2645config MITIGATION_SPECTRE_V2
2646	bool "Mitigate SPECTRE V2 hardware bug"
2647	default y
2648	help
2649	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2650	  V2 is a class of side channel attacks that takes advantage of
2651	  indirect branch predictors inside the processor. In Spectre variant 2
2652	  attacks, the attacker can steer speculative indirect branches in the
2653	  victim to gadget code by poisoning the branch target buffer of a CPU
2654	  used for predicting indirect branch addresses.
2655	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2656
2657config MITIGATION_SRBDS
2658	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2659	depends on CPU_SUP_INTEL
2660	default y
2661	help
2662	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2663	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2664	  Sampling (MDS) techniques to infer values returned from special
2665	  register accesses. An unprivileged user can extract values returned
2666	  from RDRAND and RDSEED executed on another core or sibling thread
2667	  using MDS techniques.
2668	  See also
2669	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2670
2671config MITIGATION_SSB
2672	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2673	default y
2674	help
2675	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2676	  hardware security vulnerability and its exploitation takes advantage
2677	  of speculative execution in a similar way to the Meltdown and Spectre
2678	  security vulnerabilities.
2679
2680config MITIGATION_ITS
2681	bool "Enable Indirect Target Selection mitigation"
2682	depends on CPU_SUP_INTEL && X86_64
2683	depends on MITIGATION_RETPOLINE && MITIGATION_RETHUNK
2684	select EXECMEM
2685	default y
2686	help
2687	  Enable Indirect Target Selection (ITS) mitigation. ITS is a bug in
2688	  BPU on some Intel CPUs that may allow Spectre V2 style attacks. If
2689	  disabled, mitigation cannot be enabled via cmdline.
2690	  See <file:Documentation/admin-guide/hw-vuln/indirect-target-selection.rst>
2691
2692config MITIGATION_TSA
2693	bool "Mitigate Transient Scheduler Attacks"
2694	depends on CPU_SUP_AMD
2695	default y
2696	help
2697	  Enable mitigation for Transient Scheduler Attacks. TSA is a hardware
2698	  security vulnerability on AMD CPUs which can lead to forwarding of
2699	  invalid info to subsequent instructions and thus can affect their
2700	  timing and thereby cause a leakage.
2701endif
2702
2703config ARCH_HAS_ADD_PAGES
2704	def_bool y
2705	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2706
2707menu "Power management and ACPI options"
2708
2709config ARCH_HIBERNATION_HEADER
2710	def_bool y
2711	depends on HIBERNATION
2712
2713source "kernel/power/Kconfig"
2714
2715source "drivers/acpi/Kconfig"
2716
2717config X86_APM_BOOT
2718	def_bool y
2719	depends on APM
2720
2721menuconfig APM
2722	tristate "APM (Advanced Power Management) BIOS support"
2723	depends on X86_32 && PM_SLEEP
2724	help
2725	  APM is a BIOS specification for saving power using several different
2726	  techniques. This is mostly useful for battery powered laptops with
2727	  APM compliant BIOSes. If you say Y here, the system time will be
2728	  reset after a RESUME operation, the /proc/apm device will provide
2729	  battery status information, and user-space programs will receive
2730	  notification of APM "events" (e.g. battery status change).
2731
2732	  If you select "Y" here, you can disable actual use of the APM
2733	  BIOS by passing the "apm=off" option to the kernel at boot time.
2734
2735	  Note that the APM support is almost completely disabled for
2736	  machines with more than one CPU.
2737
2738	  In order to use APM, you will need supporting software. For location
2739	  and more information, read <file:Documentation/power/apm-acpi.rst>
2740	  and the Battery Powered Linux mini-HOWTO, available from
2741	  <http://www.tldp.org/docs.html#howto>.
2742
2743	  This driver does not spin down disk drives (see the hdparm(8)
2744	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2745	  VESA-compliant "green" monitors.
2746
2747	  This driver does not support the TI 4000M TravelMate and the ACER
2748	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2749	  desktop machines also don't have compliant BIOSes, and this driver
2750	  may cause those machines to panic during the boot phase.
2751
2752	  Generally, if you don't have a battery in your machine, there isn't
2753	  much point in using this driver and you should say N. If you get
2754	  random kernel OOPSes or reboots that don't seem to be related to
2755	  anything, try disabling/enabling this option (or disabling/enabling
2756	  APM in your BIOS).
2757
2758	  Some other things you should try when experiencing seemingly random,
2759	  "weird" problems:
2760
2761	  1) make sure that you have enough swap space and that it is
2762	  enabled.
2763	  2) pass the "idle=poll" option to the kernel
2764	  3) switch on floating point emulation in the kernel and pass
2765	  the "no387" option to the kernel
2766	  4) pass the "floppy=nodma" option to the kernel
2767	  5) pass the "mem=4M" option to the kernel (thereby disabling
2768	  all but the first 4 MB of RAM)
2769	  6) make sure that the CPU is not over clocked.
2770	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2771	  8) disable the cache from your BIOS settings
2772	  9) install a fan for the video card or exchange video RAM
2773	  10) install a better fan for the CPU
2774	  11) exchange RAM chips
2775	  12) exchange the motherboard.
2776
2777	  To compile this driver as a module, choose M here: the
2778	  module will be called apm.
2779
2780if APM
2781
2782config APM_IGNORE_USER_SUSPEND
2783	bool "Ignore USER SUSPEND"
2784	help
2785	  This option will ignore USER SUSPEND requests. On machines with a
2786	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2787	  series notebooks, it is necessary to say Y because of a BIOS bug.
2788
2789config APM_DO_ENABLE
2790	bool "Enable PM at boot time"
2791	help
2792	  Enable APM features at boot time. From page 36 of the APM BIOS
2793	  specification: "When disabled, the APM BIOS does not automatically
2794	  power manage devices, enter the Standby State, enter the Suspend
2795	  State, or take power saving steps in response to CPU Idle calls."
2796	  This driver will make CPU Idle calls when Linux is idle (unless this
2797	  feature is turned off -- see "Do CPU IDLE calls", below). This
2798	  should always save battery power, but more complicated APM features
2799	  will be dependent on your BIOS implementation. You may need to turn
2800	  this option off if your computer hangs at boot time when using APM
2801	  support, or if it beeps continuously instead of suspending. Turn
2802	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2803	  T400CDT. This is off by default since most machines do fine without
2804	  this feature.
2805
2806config APM_CPU_IDLE
2807	depends on CPU_IDLE
2808	bool "Make CPU Idle calls when idle"
2809	help
2810	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2811	  On some machines, this can activate improved power savings, such as
2812	  a slowed CPU clock rate, when the machine is idle. These idle calls
2813	  are made after the idle loop has run for some length of time (e.g.,
2814	  333 mS). On some machines, this will cause a hang at boot time or
2815	  whenever the CPU becomes idle. (On machines with more than one CPU,
2816	  this option does nothing.)
2817
2818config APM_DISPLAY_BLANK
2819	bool "Enable console blanking using APM"
2820	help
2821	  Enable console blanking using the APM. Some laptops can use this to
2822	  turn off the LCD backlight when the screen blanker of the Linux
2823	  virtual console blanks the screen. Note that this is only used by
2824	  the virtual console screen blanker, and won't turn off the backlight
2825	  when using the X Window system. This also doesn't have anything to
2826	  do with your VESA-compliant power-saving monitor. Further, this
2827	  option doesn't work for all laptops -- it might not turn off your
2828	  backlight at all, or it might print a lot of errors to the console,
2829	  especially if you are using gpm.
2830
2831config APM_ALLOW_INTS
2832	bool "Allow interrupts during APM BIOS calls"
2833	help
2834	  Normally we disable external interrupts while we are making calls to
2835	  the APM BIOS as a measure to lessen the effects of a badly behaving
2836	  BIOS implementation.  The BIOS should reenable interrupts if it
2837	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2838	  many of the newer IBM Thinkpads.  If you experience hangs when you
2839	  suspend, try setting this to Y.  Otherwise, say N.
2840
2841endif # APM
2842
2843source "drivers/cpufreq/Kconfig"
2844
2845source "drivers/cpuidle/Kconfig"
2846
2847source "drivers/idle/Kconfig"
2848
2849endmenu
2850
2851menu "Bus options (PCI etc.)"
2852
2853choice
2854	prompt "PCI access mode"
2855	depends on X86_32 && PCI
2856	default PCI_GOANY
2857	help
2858	  On PCI systems, the BIOS can be used to detect the PCI devices and
2859	  determine their configuration. However, some old PCI motherboards
2860	  have BIOS bugs and may crash if this is done. Also, some embedded
2861	  PCI-based systems don't have any BIOS at all. Linux can also try to
2862	  detect the PCI hardware directly without using the BIOS.
2863
2864	  With this option, you can specify how Linux should detect the
2865	  PCI devices. If you choose "BIOS", the BIOS will be used,
2866	  if you choose "Direct", the BIOS won't be used, and if you
2867	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2868	  If you choose "Any", the kernel will try MMCONFIG, then the
2869	  direct access method and falls back to the BIOS if that doesn't
2870	  work. If unsure, go with the default, which is "Any".
2871
2872config PCI_GOBIOS
2873	bool "BIOS"
2874
2875config PCI_GOMMCONFIG
2876	bool "MMConfig"
2877
2878config PCI_GODIRECT
2879	bool "Direct"
2880
2881config PCI_GOOLPC
2882	bool "OLPC XO-1"
2883	depends on OLPC
2884
2885config PCI_GOANY
2886	bool "Any"
2887
2888endchoice
2889
2890config PCI_BIOS
2891	def_bool y
2892	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2893
2894# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2895config PCI_DIRECT
2896	def_bool y
2897	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2898
2899config PCI_MMCONFIG
2900	bool "Support mmconfig PCI config space access" if X86_64
2901	default y
2902	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2903	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2904	help
2905	  Add support for accessing the PCI configuration space as a memory
2906	  mapped area. It is the recommended method if the system supports
2907	  this (it must have PCI Express and ACPI for it to be available).
2908
2909	  In the unlikely case that enabling this configuration option causes
2910	  problems, the mechanism can be switched off with the 'pci=nommconf'
2911	  command line parameter.
2912
2913	  Say N only if you are sure that your platform does not support this
2914	  access method or you have problems caused by it.
2915
2916	  Say Y otherwise.
2917
2918config PCI_OLPC
2919	def_bool y
2920	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2921
2922config PCI_XEN
2923	def_bool y
2924	depends on PCI && XEN
2925
2926config MMCONF_FAM10H
2927	def_bool y
2928	depends on X86_64 && PCI_MMCONFIG && ACPI
2929
2930config PCI_CNB20LE_QUIRK
2931	bool "Read PCI host bridge windows from the CNB20LE chipset" if EXPERT
2932	depends on X86_32 && PCI
2933	help
2934	  Read the PCI windows out of the CNB20LE host bridge. This allows
2935	  PCI hotplug to work on systems with the CNB20LE chipset which do
2936	  not have ACPI.
2937
2938	  The ServerWorks (later Broadcom) CNB20LE was a chipset designed
2939	  most probably only for Pentium III.
2940
2941	  To find out if you have such a chipset, search for a PCI device with
2942	  1166:0009 PCI IDs, for example by executing
2943		lspci -nn | grep '1166:0009'
2944	  The code is inactive if there is none.
2945
2946	  There's no public spec for this chipset, and this functionality
2947	  is known to be incomplete.
2948
2949	  You should say N unless you know you need this.
2950
2951config ISA_BUS
2952	bool "ISA bus support on modern systems" if EXPERT
2953	help
2954	  Expose ISA bus device drivers and options available for selection and
2955	  configuration. Enable this option if your target machine has an ISA
2956	  bus. ISA is an older system, displaced by PCI and newer bus
2957	  architectures -- if your target machine is modern, it probably does
2958	  not have an ISA bus.
2959
2960	  If unsure, say N.
2961
2962# x86_64 have no ISA slots, but can have ISA-style DMA.
2963config ISA_DMA_API
2964	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2965	default y
2966	help
2967	  Enables ISA-style DMA support for devices requiring such controllers.
2968	  If unsure, say Y.
2969
2970if X86_32
2971
2972config ISA
2973	bool "ISA support"
2974	help
2975	  Find out whether you have ISA slots on your motherboard.  ISA is the
2976	  name of a bus system, i.e. the way the CPU talks to the other stuff
2977	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2978	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2979	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2980
2981config SCx200
2982	tristate "NatSemi SCx200 support"
2983	help
2984	  This provides basic support for National Semiconductor's
2985	  (now AMD's) Geode processors.  The driver probes for the
2986	  PCI-IDs of several on-chip devices, so its a good dependency
2987	  for other scx200_* drivers.
2988
2989	  If compiled as a module, the driver is named scx200.
2990
2991config SCx200HR_TIMER
2992	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2993	depends on SCx200
2994	default y
2995	help
2996	  This driver provides a clocksource built upon the on-chip
2997	  27MHz high-resolution timer.  Its also a workaround for
2998	  NSC Geode SC-1100's buggy TSC, which loses time when the
2999	  processor goes idle (as is done by the scheduler).  The
3000	  other workaround is idle=poll boot option.
3001
3002config OLPC
3003	bool "One Laptop Per Child support"
3004	depends on !X86_PAE
3005	select GPIOLIB
3006	select OF
3007	select OF_PROMTREE
3008	select IRQ_DOMAIN
3009	select OLPC_EC
3010	help
3011	  Add support for detecting the unique features of the OLPC
3012	  XO hardware.
3013
3014config OLPC_XO1_PM
3015	bool "OLPC XO-1 Power Management"
3016	depends on OLPC && MFD_CS5535=y && PM_SLEEP
3017	help
3018	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
3019
3020config OLPC_XO1_RTC
3021	bool "OLPC XO-1 Real Time Clock"
3022	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3023	help
3024	  Add support for the XO-1 real time clock, which can be used as a
3025	  programmable wakeup source.
3026
3027config OLPC_XO1_SCI
3028	bool "OLPC XO-1 SCI extras"
3029	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3030	depends on INPUT=y
3031	select POWER_SUPPLY
3032	help
3033	  Add support for SCI-based features of the OLPC XO-1 laptop:
3034	   - EC-driven system wakeups
3035	   - Power button
3036	   - Ebook switch
3037	   - Lid switch
3038	   - AC adapter status updates
3039	   - Battery status updates
3040
3041config OLPC_XO15_SCI
3042	bool "OLPC XO-1.5 SCI extras"
3043	depends on OLPC && ACPI
3044	select POWER_SUPPLY
3045	help
3046	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3047	   - EC-driven system wakeups
3048	   - AC adapter status updates
3049	   - Battery status updates
3050
3051config GEODE_COMMON
3052	bool
3053
3054config ALIX
3055	bool "PCEngines ALIX System Support (LED setup)"
3056	select GPIOLIB
3057	select GEODE_COMMON
3058	help
3059	  This option enables system support for the PCEngines ALIX.
3060	  At present this just sets up LEDs for GPIO control on
3061	  ALIX2/3/6 boards.  However, other system specific setup should
3062	  get added here.
3063
3064	  Note: You must still enable the drivers for GPIO and LED support
3065	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3066
3067	  Note: You have to set alix.force=1 for boards with Award BIOS.
3068
3069config NET5501
3070	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3071	select GPIOLIB
3072	select GEODE_COMMON
3073	help
3074	  This option enables system support for the Soekris Engineering net5501.
3075
3076config GEOS
3077	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3078	select GPIOLIB
3079	select GEODE_COMMON
3080	depends on DMI
3081	help
3082	  This option enables system support for the Traverse Technologies GEOS.
3083
3084config TS5500
3085	bool "Technologic Systems TS-5500 platform support"
3086	depends on MELAN
3087	select CHECK_SIGNATURE
3088	select NEW_LEDS
3089	select LEDS_CLASS
3090	help
3091	  This option enables system support for the Technologic Systems TS-5500.
3092
3093endif # X86_32
3094
3095config AMD_NB
3096	def_bool y
3097	depends on AMD_NODE
3098
3099config AMD_NODE
3100	def_bool y
3101	depends on CPU_SUP_AMD && PCI
3102
3103endmenu
3104
3105menu "Binary Emulations"
3106
3107config IA32_EMULATION
3108	bool "IA32 Emulation"
3109	depends on X86_64
3110	select ARCH_WANT_OLD_COMPAT_IPC
3111	select BINFMT_ELF
3112	select COMPAT_OLD_SIGACTION
3113	help
3114	  Include code to run legacy 32-bit programs under a
3115	  64-bit kernel. You should likely turn this on, unless you're
3116	  100% sure that you don't have any 32-bit programs left.
3117
3118config IA32_EMULATION_DEFAULT_DISABLED
3119	bool "IA32 emulation disabled by default"
3120	default n
3121	depends on IA32_EMULATION
3122	help
3123	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3124	  processes and access to 32-bit syscalls. If unsure, leave it to its
3125	  default value.
3126
3127config X86_X32_ABI
3128	bool "x32 ABI for 64-bit mode"
3129	depends on X86_64
3130	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3131	# compressed debug sections to x86_x32 properly:
3132	# https://github.com/ClangBuiltLinux/linux/issues/514
3133	# https://github.com/ClangBuiltLinux/linux/issues/1141
3134	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3135	help
3136	  Include code to run binaries for the x32 native 32-bit ABI
3137	  for 64-bit processors.  An x32 process gets access to the
3138	  full 64-bit register file and wide data path while leaving
3139	  pointers at 32 bits for smaller memory footprint.
3140
3141config COMPAT_32
3142	def_bool y
3143	depends on IA32_EMULATION || X86_32
3144	select HAVE_UID16
3145	select OLD_SIGSUSPEND3
3146
3147config COMPAT
3148	def_bool y
3149	depends on IA32_EMULATION || X86_X32_ABI
3150
3151config COMPAT_FOR_U64_ALIGNMENT
3152	def_bool y
3153	depends on COMPAT
3154
3155endmenu
3156
3157config HAVE_ATOMIC_IOMAP
3158	def_bool y
3159	depends on X86_32
3160
3161source "arch/x86/kvm/Kconfig"
3162
3163source "arch/x86/Kconfig.cpufeatures"
3164
3165source "arch/x86/Kconfig.assembler"
3166