xref: /linux/arch/x86/Kconfig (revision f49040c7aaa5532a1f94355ef5073c49e6b32349)
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 GENERIC_VDSO_32
18	select HAVE_DEBUG_STACKOVERFLOW
19	select KMAP_LOCAL
20	select MODULES_USE_ELF_REL
21	select OLD_SIGACTION
22	select ARCH_SPLIT_ARG64
23
24config X86_64
25	def_bool y
26	depends on 64BIT
27	# Options that are inherently 64-bit kernel only:
28	select ARCH_HAS_GIGANTIC_PAGE
29	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30	select ARCH_SUPPORTS_PER_VMA_LOCK
31	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
32	select HAVE_ARCH_SOFT_DIRTY
33	select MODULES_USE_ELF_RELA
34	select NEED_DMA_MAP_STATE
35	select SWIOTLB
36	select ARCH_HAS_ELFCORE_COMPAT
37	select ZONE_DMA32
38	select EXECMEM if DYNAMIC_FTRACE
39
40config FORCE_DYNAMIC_FTRACE
41	def_bool y
42	depends on X86_32
43	depends on FUNCTION_TRACER
44	select DYNAMIC_FTRACE
45	help
46	  We keep the static function tracing (!DYNAMIC_FTRACE) around
47	  in order to test the non static function tracing in the
48	  generic code, as other architectures still use it. But we
49	  only need to keep it around for x86_64. No need to keep it
50	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
51#
52# Arch settings
53#
54# ( Note that options that are marked 'if X86_64' could in principle be
55#   ported to 32-bit as well. )
56#
57config X86
58	def_bool y
59	#
60	# Note: keep this list sorted alphabetically
61	#
62	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
63	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
64	select ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
65	select ARCH_32BIT_OFF_T			if X86_32
66	select ARCH_CLOCKSOURCE_INIT
67	select ARCH_CONFIGURES_CPU_MITIGATIONS
68	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
69	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
70	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
71	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
72	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
73	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
74	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
75	select ARCH_HAS_CACHE_LINE_SIZE
76	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
77	select ARCH_HAS_CPU_FINALIZE_INIT
78	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
79	select ARCH_HAS_CRC32
80	select ARCH_HAS_CRC64			if X86_64
81	select ARCH_HAS_CRC_T10DIF
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
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_DEVMAP		if X86_64
102	select ARCH_HAS_PTE_SPECIAL
103	select ARCH_HAS_HW_PTE_YOUNG
104	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
105	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
106	select ARCH_HAS_COPY_MC			if X86_64
107	select ARCH_HAS_SET_MEMORY
108	select ARCH_HAS_SET_DIRECT_MAP
109	select ARCH_HAS_STRICT_KERNEL_RWX
110	select ARCH_HAS_STRICT_MODULE_RWX
111	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
112	select ARCH_HAS_SYSCALL_WRAPPER
113	select ARCH_HAS_UBSAN
114	select ARCH_HAS_DEBUG_WX
115	select ARCH_HAS_ZONE_DMA_SET if EXPERT
116	select ARCH_HAVE_NMI_SAFE_CMPXCHG
117	select ARCH_HAVE_EXTRA_ELF_NOTES
118	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
119	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
120	select ARCH_MIGHT_HAVE_PC_PARPORT
121	select ARCH_MIGHT_HAVE_PC_SERIO
122	select ARCH_STACKWALK
123	select ARCH_SUPPORTS_ACPI
124	select ARCH_SUPPORTS_ATOMIC_RMW
125	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
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
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_WANTS_THP_SWAP		if X86_64
152	select ARCH_HAS_PARANOID_L1D_FLUSH
153	select BUILDTIME_TABLE_SORT
154	select CLKEVT_I8253
155	select CLOCKSOURCE_WATCHDOG
156	# Word-size accesses may read uninitialized data past the trailing \0
157	# in strings and cause false KMSAN reports.
158	select DCACHE_WORD_ACCESS		if !KMSAN
159	select DYNAMIC_SIGFRAME
160	select EDAC_ATOMIC_SCRUB
161	select EDAC_SUPPORT
162	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
163	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
164	select GENERIC_CLOCKEVENTS_MIN_ADJUST
165	select GENERIC_CMOS_UPDATE
166	select GENERIC_CPU_AUTOPROBE
167	select GENERIC_CPU_DEVICES
168	select GENERIC_CPU_VULNERABILITIES
169	select GENERIC_EARLY_IOREMAP
170	select GENERIC_ENTRY
171	select GENERIC_IOMAP
172	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
173	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
174	select GENERIC_IRQ_MIGRATION		if SMP
175	select GENERIC_IRQ_PROBE
176	select GENERIC_IRQ_RESERVATION_MODE
177	select GENERIC_IRQ_SHOW
178	select GENERIC_PENDING_IRQ		if SMP
179	select GENERIC_PTDUMP
180	select GENERIC_SMP_IDLE_THREAD
181	select GENERIC_TIME_VSYSCALL
182	select GENERIC_GETTIMEOFDAY
183	select GENERIC_VDSO_DATA_STORE
184	select GENERIC_VDSO_TIME_NS
185	select GENERIC_VDSO_OVERFLOW_PROTECT
186	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
187	select HARDIRQS_SW_RESEND
188	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
189	select HAS_IOPORT
190	select HAVE_ACPI_APEI			if ACPI
191	select HAVE_ACPI_APEI_NMI		if ACPI
192	select HAVE_ALIGNED_STRUCT_PAGE
193	select HAVE_ARCH_AUDITSYSCALL
194	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
195	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
196	select HAVE_ARCH_JUMP_LABEL
197	select HAVE_ARCH_JUMP_LABEL_RELATIVE
198	select HAVE_ARCH_KASAN			if X86_64
199	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
200	select HAVE_ARCH_KFENCE
201	select HAVE_ARCH_KMSAN			if X86_64
202	select HAVE_ARCH_KGDB
203	select HAVE_ARCH_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_STACKLEAK
210	select HAVE_ARCH_TRACEHOOK
211	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
212	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
213	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
214	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
215	select HAVE_ARCH_VMAP_STACK		if X86_64
216	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
217	select HAVE_ARCH_WITHIN_STACK_FRAMES
218	select HAVE_ASM_MODVERSIONS
219	select HAVE_CMPXCHG_DOUBLE
220	select HAVE_CMPXCHG_LOCAL
221	select HAVE_CONTEXT_TRACKING_USER		if X86_64
222	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
223	select HAVE_C_RECORDMCOUNT
224	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
225	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
226	select HAVE_BUILDTIME_MCOUNT_SORT
227	select HAVE_DEBUG_KMEMLEAK
228	select HAVE_DMA_CONTIGUOUS
229	select HAVE_DYNAMIC_FTRACE
230	select HAVE_DYNAMIC_FTRACE_WITH_REGS
231	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
232	select HAVE_FTRACE_REGS_HAVING_PT_REGS	if X86_64
233	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
234	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
235	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
236	select HAVE_EBPF_JIT
237	select HAVE_EFFICIENT_UNALIGNED_ACCESS
238	select HAVE_EISA			if X86_32
239	select HAVE_EXIT_THREAD
240	select HAVE_GUP_FAST
241	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
242	select HAVE_FTRACE_GRAPH_FUNC		if HAVE_FUNCTION_GRAPH_TRACER
243	select HAVE_FTRACE_MCOUNT_RECORD
244	select HAVE_FUNCTION_GRAPH_FREGS	if HAVE_FUNCTION_GRAPH_TRACER
245	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
246	select HAVE_FUNCTION_TRACER
247	select HAVE_GCC_PLUGINS
248	select HAVE_HW_BREAKPOINT
249	select HAVE_IOREMAP_PROT
250	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
251	select HAVE_IRQ_TIME_ACCOUNTING
252	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
253	select HAVE_KERNEL_BZIP2
254	select HAVE_KERNEL_GZIP
255	select HAVE_KERNEL_LZ4
256	select HAVE_KERNEL_LZMA
257	select HAVE_KERNEL_LZO
258	select HAVE_KERNEL_XZ
259	select HAVE_KERNEL_ZSTD
260	select HAVE_KPROBES
261	select HAVE_KPROBES_ON_FTRACE
262	select HAVE_FUNCTION_ERROR_INJECTION
263	select HAVE_KRETPROBES
264	select HAVE_RETHOOK
265	select HAVE_LIVEPATCH			if X86_64
266	select HAVE_MIXED_BREAKPOINTS_REGS
267	select HAVE_MOD_ARCH_SPECIFIC
268	select HAVE_MOVE_PMD
269	select HAVE_MOVE_PUD
270	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
271	select HAVE_NMI
272	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
273	select HAVE_OBJTOOL			if X86_64
274	select HAVE_OPTPROBES
275	select HAVE_PAGE_SIZE_4KB
276	select HAVE_PCSPKR_PLATFORM
277	select HAVE_PERF_EVENTS
278	select HAVE_PERF_EVENTS_NMI
279	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
280	select HAVE_PCI
281	select HAVE_PERF_REGS
282	select HAVE_PERF_USER_STACK_DUMP
283	select MMU_GATHER_RCU_TABLE_FREE
284	select MMU_GATHER_MERGE_VMAS
285	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
286	select HAVE_REGS_AND_STACK_ACCESS_API
287	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
288	select HAVE_FUNCTION_ARG_ACCESS_API
289	select HAVE_SETUP_PER_CPU_AREA
290	select HAVE_SOFTIRQ_ON_OWN_STACK
291	select HAVE_STACKPROTECTOR
292	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
293	select HAVE_STATIC_CALL
294	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
295	select HAVE_PREEMPT_DYNAMIC_CALL
296	select HAVE_RSEQ
297	select HAVE_RUST			if X86_64
298	select HAVE_SYSCALL_TRACEPOINTS
299	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
300	select HAVE_UNSTABLE_SCHED_CLOCK
301	select HAVE_USER_RETURN_NOTIFIER
302	select HAVE_GENERIC_VDSO
303	select VDSO_GETRANDOM			if X86_64
304	select HOTPLUG_PARALLEL			if SMP && X86_64
305	select HOTPLUG_SMT			if SMP
306	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
307	select IRQ_FORCED_THREADING
308	select LOCK_MM_AND_FIND_VMA
309	select NEED_PER_CPU_EMBED_FIRST_CHUNK
310	select NEED_PER_CPU_PAGE_FIRST_CHUNK
311	select NEED_SG_DMA_LENGTH
312	select NUMA_MEMBLKS			if NUMA
313	select PCI_DOMAINS			if PCI
314	select PCI_LOCKLESS_CONFIG		if PCI
315	select PERF_EVENTS
316	select RTC_LIB
317	select RTC_MC146818_LIB
318	select SPARSE_IRQ
319	select SYSCTL_EXCEPTION_TRACE
320	select THREAD_INFO_IN_TASK
321	select TRACE_IRQFLAGS_SUPPORT
322	select TRACE_IRQFLAGS_NMI_SUPPORT
323	select USER_STACKTRACE_SUPPORT
324	select HAVE_ARCH_KCSAN			if X86_64
325	select PROC_PID_ARCH_STATUS		if PROC_FS
326	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
327	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
328	select FUNCTION_ALIGNMENT_4B
329	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
330	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
331	select ARCH_SUPPORTS_PT_RECLAIM		if X86_64
332
333config INSTRUCTION_DECODER
334	def_bool y
335	depends on KPROBES || PERF_EVENTS || UPROBES
336
337config OUTPUT_FORMAT
338	string
339	default "elf32-i386" if X86_32
340	default "elf64-x86-64" if X86_64
341
342config LOCKDEP_SUPPORT
343	def_bool y
344
345config STACKTRACE_SUPPORT
346	def_bool y
347
348config MMU
349	def_bool y
350
351config ARCH_MMAP_RND_BITS_MIN
352	default 28 if 64BIT
353	default 8
354
355config ARCH_MMAP_RND_BITS_MAX
356	default 32 if 64BIT
357	default 16
358
359config ARCH_MMAP_RND_COMPAT_BITS_MIN
360	default 8
361
362config ARCH_MMAP_RND_COMPAT_BITS_MAX
363	default 16
364
365config SBUS
366	bool
367
368config GENERIC_ISA_DMA
369	def_bool y
370	depends on ISA_DMA_API
371
372config GENERIC_CSUM
373	bool
374	default y if KMSAN || KASAN
375
376config GENERIC_BUG
377	def_bool y
378	depends on BUG
379	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
380
381config GENERIC_BUG_RELATIVE_POINTERS
382	bool
383
384config ARCH_MAY_HAVE_PC_FDC
385	def_bool y
386	depends on ISA_DMA_API
387
388config GENERIC_CALIBRATE_DELAY
389	def_bool y
390
391config ARCH_HAS_CPU_RELAX
392	def_bool y
393
394config ARCH_HIBERNATION_POSSIBLE
395	def_bool y
396
397config ARCH_SUSPEND_POSSIBLE
398	def_bool y
399
400config AUDIT_ARCH
401	def_bool y if X86_64
402
403config KASAN_SHADOW_OFFSET
404	hex
405	depends on KASAN
406	default 0xdffffc0000000000
407
408config HAVE_INTEL_TXT
409	def_bool y
410	depends on INTEL_IOMMU && ACPI
411
412config X86_64_SMP
413	def_bool y
414	depends on X86_64 && SMP
415
416config ARCH_SUPPORTS_UPROBES
417	def_bool y
418
419config FIX_EARLYCON_MEM
420	def_bool y
421
422config DYNAMIC_PHYSICAL_MASK
423	bool
424
425config PGTABLE_LEVELS
426	int
427	default 5 if X86_5LEVEL
428	default 4 if X86_64
429	default 3 if X86_PAE
430	default 2
431
432menu "Processor type and features"
433
434config SMP
435	bool "Symmetric multi-processing support"
436	help
437	  This enables support for systems with more than one CPU. If you have
438	  a system with only one CPU, say N. If you have a system with more
439	  than one CPU, say Y.
440
441	  If you say N here, the kernel will run on uni- and multiprocessor
442	  machines, but will use only one CPU of a multiprocessor machine. If
443	  you say Y here, the kernel will run on many, but not all,
444	  uniprocessor machines. On a uniprocessor machine, the kernel
445	  will run faster if you say N here.
446
447	  Note that if you say Y here and choose architecture "586" or
448	  "Pentium" under "Processor family", the kernel will not work on 486
449	  architectures. Similarly, multiprocessor kernels for the "PPro"
450	  architecture may not work on all Pentium based boards.
451
452	  People using multiprocessor machines who say Y here should also say
453	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
454	  Management" code will be disabled if you say Y here.
455
456	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
457	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
458	  <http://www.tldp.org/docs.html#howto>.
459
460	  If you don't know what to do here, say N.
461
462config X86_X2APIC
463	bool "Support x2apic"
464	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
465	help
466	  This enables x2apic support on CPUs that have this feature.
467
468	  This allows 32-bit apic IDs (so it can support very large systems),
469	  and accesses the local apic via MSRs not via mmio.
470
471	  Some Intel systems circa 2022 and later are locked into x2APIC mode
472	  and can not fall back to the legacy APIC modes if SGX or TDX are
473	  enabled in the BIOS. They will boot with very reduced functionality
474	  without enabling this option.
475
476	  If you don't know what to do here, say N.
477
478config X86_POSTED_MSI
479	bool "Enable MSI and MSI-x delivery by posted interrupts"
480	depends on X86_64 && IRQ_REMAP
481	help
482	  This enables MSIs that are under interrupt remapping to be delivered as
483	  posted interrupts to the host kernel. Interrupt throughput can
484	  potentially be improved by coalescing CPU notifications during high
485	  frequency bursts.
486
487	  If you don't know what to do here, say N.
488
489config X86_MPPARSE
490	bool "Enable MPS table" if ACPI
491	default y
492	depends on X86_LOCAL_APIC
493	help
494	  For old smp systems that do not have proper acpi support. Newer systems
495	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
496
497config X86_CPU_RESCTRL
498	bool "x86 CPU resource control support"
499	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
500	select KERNFS
501	select PROC_CPU_RESCTRL		if PROC_FS
502	select RESCTRL_FS_PSEUDO_LOCK
503	help
504	  Enable x86 CPU resource control support.
505
506	  Provide support for the allocation and monitoring of system resources
507	  usage by the CPU.
508
509	  Intel calls this Intel Resource Director Technology
510	  (Intel(R) RDT). More information about RDT can be found in the
511	  Intel x86 Architecture Software Developer Manual.
512
513	  AMD calls this AMD Platform Quality of Service (AMD QoS).
514	  More information about AMD QoS can be found in the AMD64 Technology
515	  Platform Quality of Service Extensions manual.
516
517	  Say N if unsure.
518
519config RESCTRL_FS_PSEUDO_LOCK
520	bool
521	help
522	  Software mechanism to pin data in a cache portion using
523	  micro-architecture specific knowledge.
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 (Android emulator)
548		AMD Elan
549		RDC R-321x SoC
550		SGI 320/540 (Visual Workstation)
551
552	  64-bit platforms (CONFIG_64BIT=y):
553		Numascale NumaChip
554		ScaleMP vSMP
555		SGI Ultraviolet
556		Merrifield/Moorefield MID devices
557
558	  If you have one of these systems, or if you want to build a
559	  generic distribution kernel, say Y here - otherwise say N.
560
561# This is an alphabetically sorted list of 64 bit extended platforms
562# Please maintain the alphabetic order if and when there are additions
563config X86_NUMACHIP
564	bool "Numascale NumaChip"
565	depends on X86_64
566	depends on X86_EXTENDED_PLATFORM
567	depends on NUMA
568	depends on SMP
569	depends on X86_X2APIC
570	depends on PCI_MMCONFIG
571	help
572	  Adds support for Numascale NumaChip large-SMP systems. Needed to
573	  enable more than ~168 cores.
574	  If you don't have one of these, you should say N here.
575
576config X86_VSMP
577	bool "ScaleMP vSMP"
578	select HYPERVISOR_GUEST
579	select PARAVIRT
580	depends on X86_64 && PCI
581	depends on X86_EXTENDED_PLATFORM
582	depends on SMP
583	help
584	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
585	  supposed to run on these EM64T-based machines.  Only choose this option
586	  if you have one of these machines.
587
588config X86_UV
589	bool "SGI Ultraviolet"
590	depends on X86_64
591	depends on X86_EXTENDED_PLATFORM
592	depends on NUMA
593	depends on EFI
594	depends on KEXEC_CORE
595	depends on X86_X2APIC
596	depends on PCI
597	help
598	  This option is needed in order to support SGI Ultraviolet systems.
599	  If you don't have one of these, you should say N here.
600
601config X86_INTEL_MID
602	bool "Intel Z34xx/Z35xx MID platform support"
603	depends on X86_EXTENDED_PLATFORM
604	depends on X86_PLATFORM_DEVICES
605	depends on PCI
606	depends on X86_64 || (EXPERT && PCI_GOANY)
607	depends on X86_IO_APIC
608	select I2C
609	select DW_APB_TIMER
610	select INTEL_SCU_PCI
611	help
612	  Select to build a kernel capable of supporting 64-bit Intel MID
613	  (Mobile Internet Device) platform systems which do not have
614	  the PCI legacy interfaces.
615
616	  The only supported devices are the 22nm Merrified (Z34xx)
617	  and Moorefield (Z35xx) SoC used in the Intel Edison board and
618	  a small number of Android devices such as the Asus Zenfone 2,
619	  Asus FonePad 8 and Dell Venue 7.
620
621	  If you are building for a PC class system or non-MID tablet
622	  SoCs like Bay Trail (Z36xx/Z37xx), say N here.
623
624	  Intel MID platforms are based on an Intel processor and chipset which
625	  consume less power than most of the x86 derivatives.
626
627config X86_GOLDFISH
628	bool "Goldfish (Virtual Platform)"
629	depends on X86_EXTENDED_PLATFORM
630	help
631	  Enable support for the Goldfish virtual platform used primarily
632	  for Android development. Unless you are building for the Android
633	  Goldfish emulator say N here.
634
635# Following is an alphabetically sorted list of 32 bit extended platforms
636# Please maintain the alphabetic order if and when there are additions
637
638config X86_INTEL_CE
639	bool "CE4100 TV platform"
640	depends on PCI
641	depends on PCI_GODIRECT
642	depends on X86_IO_APIC
643	depends on X86_32
644	depends on X86_EXTENDED_PLATFORM
645	select X86_REBOOTFIXUPS
646	select OF
647	select OF_EARLY_FLATTREE
648	help
649	  Select for the Intel CE media processor (CE4100) SOC.
650	  This option compiles in support for the CE4100 SOC for settop
651	  boxes and media devices.
652
653config X86_INTEL_QUARK
654	bool "Intel Quark platform support"
655	depends on X86_32
656	depends on X86_EXTENDED_PLATFORM
657	depends on X86_PLATFORM_DEVICES
658	depends on X86_TSC
659	depends on PCI
660	depends on PCI_GOANY
661	depends on X86_IO_APIC
662	select IOSF_MBI
663	select INTEL_IMR
664	select COMMON_CLK
665	help
666	  Select to include support for Quark X1000 SoC.
667	  Say Y here if you have a Quark based system such as the Arduino
668	  compatible Intel Galileo.
669
670config X86_INTEL_LPSS
671	bool "Intel Low Power Subsystem Support"
672	depends on X86 && ACPI && PCI
673	select COMMON_CLK
674	select PINCTRL
675	select IOSF_MBI
676	help
677	  Select to build support for Intel Low Power Subsystem such as
678	  found on Intel Lynxpoint PCH. Selecting this option enables
679	  things like clock tree (common clock framework) and pincontrol
680	  which are needed by the LPSS peripheral drivers.
681
682config X86_AMD_PLATFORM_DEVICE
683	bool "AMD ACPI2Platform devices support"
684	depends on ACPI
685	select COMMON_CLK
686	select PINCTRL
687	help
688	  Select to interpret AMD specific ACPI device to platform device
689	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
690	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
691	  implemented under PINCTRL subsystem.
692
693config IOSF_MBI
694	tristate "Intel SoC IOSF Sideband support for SoC platforms"
695	depends on PCI
696	help
697	  This option enables sideband register access support for Intel SoC
698	  platforms. On these platforms the IOSF sideband is used in lieu of
699	  MSR's for some register accesses, mostly but not limited to thermal
700	  and power. Drivers may query the availability of this device to
701	  determine if they need the sideband in order to work on these
702	  platforms. The sideband is available on the following SoC products.
703	  This list is not meant to be exclusive.
704	   - BayTrail
705	   - Braswell
706	   - Quark
707
708	  You should say Y if you are running a kernel on one of these SoC's.
709
710config IOSF_MBI_DEBUG
711	bool "Enable IOSF sideband access through debugfs"
712	depends on IOSF_MBI && DEBUG_FS
713	help
714	  Select this option to expose the IOSF sideband access registers (MCR,
715	  MDR, MCRX) through debugfs to write and read register information from
716	  different units on the SoC. This is most useful for obtaining device
717	  state information for debug and analysis. As this is a general access
718	  mechanism, users of this option would have specific knowledge of the
719	  device they want to access.
720
721	  If you don't require the option or are in doubt, say N.
722
723config X86_RDC321X
724	bool "RDC R-321x SoC"
725	depends on X86_32
726	depends on X86_EXTENDED_PLATFORM
727	select M486
728	select X86_REBOOTFIXUPS
729	help
730	  This option is needed for RDC R-321x system-on-chip, also known
731	  as R-8610-(G).
732	  If you don't have one of these chips, you should say N here.
733
734config X86_SUPPORTS_MEMORY_FAILURE
735	def_bool y
736	# MCE code calls memory_failure():
737	depends on X86_MCE
738	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
739	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
740	depends on X86_64 || !SPARSEMEM
741	select ARCH_SUPPORTS_MEMORY_FAILURE
742
743config X86_32_IRIS
744	tristate "Eurobraille/Iris poweroff module"
745	depends on X86_32
746	help
747	  The Iris machines from EuroBraille do not have APM or ACPI support
748	  to shut themselves down properly.  A special I/O sequence is
749	  needed to do so, which is what this module does at
750	  kernel shutdown.
751
752	  This is only for Iris machines from EuroBraille.
753
754	  If unused, say N.
755
756config SCHED_OMIT_FRAME_POINTER
757	def_bool y
758	prompt "Single-depth WCHAN output"
759	depends on X86
760	help
761	  Calculate simpler /proc/<PID>/wchan values. If this option
762	  is disabled then wchan values will recurse back to the
763	  caller function. This provides more accurate wchan values,
764	  at the expense of slightly more scheduling overhead.
765
766	  If in doubt, say "Y".
767
768menuconfig HYPERVISOR_GUEST
769	bool "Linux guest support"
770	help
771	  Say Y here to enable options for running Linux under various hyper-
772	  visors. This option enables basic hypervisor detection and platform
773	  setup.
774
775	  If you say N, all options in this submenu will be skipped and
776	  disabled, and Linux guest support won't be built in.
777
778if HYPERVISOR_GUEST
779
780config PARAVIRT
781	bool "Enable paravirtualization code"
782	depends on HAVE_STATIC_CALL
783	help
784	  This changes the kernel so it can modify itself when it is run
785	  under a hypervisor, potentially improving performance significantly
786	  over full virtualization.  However, when run without a hypervisor
787	  the kernel is theoretically slower and slightly larger.
788
789config PARAVIRT_XXL
790	bool
791
792config PARAVIRT_DEBUG
793	bool "paravirt-ops debugging"
794	depends on PARAVIRT && DEBUG_KERNEL
795	help
796	  Enable to debug paravirt_ops internals.  Specifically, BUG if
797	  a paravirt_op is missing when it is called.
798
799config PARAVIRT_SPINLOCKS
800	bool "Paravirtualization layer for spinlocks"
801	depends on PARAVIRT && SMP
802	help
803	  Paravirtualized spinlocks allow a pvops backend to replace the
804	  spinlock implementation with something virtualization-friendly
805	  (for example, block the virtual CPU rather than spinning).
806
807	  It has a minimal impact on native kernels and gives a nice performance
808	  benefit on paravirtualized KVM / Xen kernels.
809
810	  If you are unsure how to answer this question, answer Y.
811
812config X86_HV_CALLBACK_VECTOR
813	def_bool n
814
815source "arch/x86/xen/Kconfig"
816
817config KVM_GUEST
818	bool "KVM Guest support (including kvmclock)"
819	depends on PARAVIRT
820	select PARAVIRT_CLOCK
821	select ARCH_CPUIDLE_HALTPOLL
822	select X86_HV_CALLBACK_VECTOR
823	default y
824	help
825	  This option enables various optimizations for running under the KVM
826	  hypervisor. It includes a paravirtualized clock, so that instead
827	  of relying on a PIT (or probably other) emulation by the
828	  underlying device model, the host provides the guest with
829	  timing infrastructure such as time of day, and system time
830
831config ARCH_CPUIDLE_HALTPOLL
832	def_bool n
833	prompt "Disable host haltpoll when loading haltpoll driver"
834	help
835	  If virtualized under KVM, disable host haltpoll.
836
837config PVH
838	bool "Support for running PVH guests"
839	help
840	  This option enables the PVH entry point for guest virtual machines
841	  as specified in the x86/HVM direct boot ABI.
842
843config PARAVIRT_TIME_ACCOUNTING
844	bool "Paravirtual steal time accounting"
845	depends on PARAVIRT
846	help
847	  Select this option to enable fine granularity task steal time
848	  accounting. Time spent executing other tasks in parallel with
849	  the current vCPU is discounted from the vCPU power. To account for
850	  that, there can be a small performance impact.
851
852	  If in doubt, say N here.
853
854config PARAVIRT_CLOCK
855	bool
856
857config JAILHOUSE_GUEST
858	bool "Jailhouse non-root cell support"
859	depends on X86_64 && PCI
860	select X86_PM_TIMER
861	help
862	  This option allows to run Linux as guest in a Jailhouse non-root
863	  cell. You can leave this option disabled if you only want to start
864	  Jailhouse and run Linux afterwards in the root cell.
865
866config ACRN_GUEST
867	bool "ACRN Guest support"
868	depends on X86_64
869	select X86_HV_CALLBACK_VECTOR
870	help
871	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
872	  a flexible, lightweight reference open-source hypervisor, built with
873	  real-time and safety-criticality in mind. It is built for embedded
874	  IOT with small footprint and real-time features. More details can be
875	  found in https://projectacrn.org/.
876
877config INTEL_TDX_GUEST
878	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
879	depends on X86_64 && CPU_SUP_INTEL
880	depends on X86_X2APIC
881	depends on EFI_STUB
882	select ARCH_HAS_CC_PLATFORM
883	select X86_MEM_ENCRYPT
884	select X86_MCE
885	select UNACCEPTED_MEMORY
886	help
887	  Support running as a guest under Intel TDX.  Without this support,
888	  the guest kernel can not boot or run under TDX.
889	  TDX includes memory encryption and integrity capabilities
890	  which protect the confidentiality and integrity of guest
891	  memory contents and CPU state. TDX guests are protected from
892	  some attacks from the VMM.
893
894endif # HYPERVISOR_GUEST
895
896source "arch/x86/Kconfig.cpu"
897
898config HPET_TIMER
899	def_bool X86_64
900	prompt "HPET Timer Support" if X86_32
901	help
902	  Use the IA-PC HPET (High Precision Event Timer) to manage
903	  time in preference to the PIT and RTC, if a HPET is
904	  present.
905	  HPET is the next generation timer replacing legacy 8254s.
906	  The HPET provides a stable time base on SMP
907	  systems, unlike the TSC, but it is more expensive to access,
908	  as it is off-chip.  The interface used is documented
909	  in the HPET spec, revision 1.
910
911	  You can safely choose Y here.  However, HPET will only be
912	  activated if the platform and the BIOS support this feature.
913	  Otherwise the 8254 will be used for timing services.
914
915	  Choose N to continue using the legacy 8254 timer.
916
917config HPET_EMULATE_RTC
918	def_bool y
919	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
920
921# Mark as expert because too many people got it wrong.
922# The code disables itself when not needed.
923config DMI
924	default y
925	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
926	bool "Enable DMI scanning" if EXPERT
927	help
928	  Enabled scanning of DMI to identify machine quirks. Say Y
929	  here unless you have verified that your setup is not
930	  affected by entries in the DMI blacklist. Required by PNP
931	  BIOS code.
932
933config GART_IOMMU
934	bool "Old AMD GART IOMMU support"
935	select IOMMU_HELPER
936	select SWIOTLB
937	depends on X86_64 && PCI && AMD_NB
938	help
939	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
940	  GART based hardware IOMMUs.
941
942	  The GART supports full DMA access for devices with 32-bit access
943	  limitations, on systems with more than 3 GB. This is usually needed
944	  for USB, sound, many IDE/SATA chipsets and some other devices.
945
946	  Newer systems typically have a modern AMD IOMMU, supported via
947	  the CONFIG_AMD_IOMMU=y config option.
948
949	  In normal configurations this driver is only active when needed:
950	  there's more than 3 GB of memory and the system contains a
951	  32-bit limited device.
952
953	  If unsure, say Y.
954
955config BOOT_VESA_SUPPORT
956	bool
957	help
958	  If true, at least one selected framebuffer driver can take advantage
959	  of VESA video modes set at an early boot stage via the vga= parameter.
960
961config MAXSMP
962	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
963	depends on X86_64 && SMP && DEBUG_KERNEL
964	select CPUMASK_OFFSTACK
965	help
966	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
967	  If unsure, say N.
968
969#
970# The maximum number of CPUs supported:
971#
972# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
973# and which can be configured interactively in the
974# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
975#
976# The ranges are different on 32-bit and 64-bit kernels, depending on
977# hardware capabilities and scalability features of the kernel.
978#
979# ( If MAXSMP is enabled we just use the highest possible value and disable
980#   interactive configuration. )
981#
982
983config NR_CPUS_RANGE_BEGIN
984	int
985	default NR_CPUS_RANGE_END if MAXSMP
986	default    1 if !SMP
987	default    2
988
989config NR_CPUS_RANGE_END
990	int
991	depends on X86_32
992	default    8 if  SMP
993	default    1 if !SMP
994
995config NR_CPUS_RANGE_END
996	int
997	depends on X86_64
998	default 8192 if  SMP && CPUMASK_OFFSTACK
999	default  512 if  SMP && !CPUMASK_OFFSTACK
1000	default    1 if !SMP
1001
1002config NR_CPUS_DEFAULT
1003	int
1004	depends on X86_32
1005	default    8 if  SMP
1006	default    1 if !SMP
1007
1008config NR_CPUS_DEFAULT
1009	int
1010	depends on X86_64
1011	default 8192 if  MAXSMP
1012	default   64 if  SMP
1013	default    1 if !SMP
1014
1015config NR_CPUS
1016	int "Maximum number of CPUs" if SMP && !MAXSMP
1017	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1018	default NR_CPUS_DEFAULT
1019	help
1020	  This allows you to specify the maximum number of CPUs which this
1021	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1022	  supported value is 8192, otherwise the maximum value is 512.  The
1023	  minimum value which makes sense is 2.
1024
1025	  This is purely to save memory: each supported CPU adds about 8KB
1026	  to the kernel image.
1027
1028config SCHED_CLUSTER
1029	bool "Cluster scheduler support"
1030	depends on SMP
1031	default y
1032	help
1033	  Cluster scheduler support improves the CPU scheduler's decision
1034	  making when dealing with machines that have clusters of CPUs.
1035	  Cluster usually means a couple of CPUs which are placed closely
1036	  by sharing mid-level caches, last-level cache tags or internal
1037	  busses.
1038
1039config SCHED_SMT
1040	def_bool y if SMP
1041
1042config SCHED_MC
1043	def_bool y
1044	prompt "Multi-core scheduler support"
1045	depends on SMP
1046	help
1047	  Multi-core scheduler support improves the CPU scheduler's decision
1048	  making when dealing with multi-core CPU chips at a cost of slightly
1049	  increased overhead in some places. If unsure say N here.
1050
1051config SCHED_MC_PRIO
1052	bool "CPU core priorities scheduler support"
1053	depends on SCHED_MC
1054	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1055	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1056	select CPU_FREQ
1057	default y
1058	help
1059	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1060	  core ordering determined at manufacturing time, which allows
1061	  certain cores to reach higher turbo frequencies (when running
1062	  single threaded workloads) than others.
1063
1064	  Enabling this kernel feature teaches the scheduler about
1065	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1066	  scheduler's CPU selection logic accordingly, so that higher
1067	  overall system performance can be achieved.
1068
1069	  This feature will have no effect on CPUs without this feature.
1070
1071	  If unsure say Y here.
1072
1073config UP_LATE_INIT
1074	def_bool y
1075	depends on !SMP && X86_LOCAL_APIC
1076
1077config X86_UP_APIC
1078	bool "Local APIC support on uniprocessors" if !PCI_MSI
1079	default PCI_MSI
1080	depends on X86_32 && !SMP
1081	help
1082	  A local APIC (Advanced Programmable Interrupt Controller) is an
1083	  integrated interrupt controller in the CPU. If you have a single-CPU
1084	  system which has a processor with a local APIC, you can say Y here to
1085	  enable and use it. If you say Y here even though your machine doesn't
1086	  have a local APIC, then the kernel will still run with no slowdown at
1087	  all. The local APIC supports CPU-generated self-interrupts (timer,
1088	  performance counters), and the NMI watchdog which detects hard
1089	  lockups.
1090
1091config X86_UP_IOAPIC
1092	bool "IO-APIC support on uniprocessors"
1093	depends on X86_UP_APIC
1094	help
1095	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1096	  SMP-capable replacement for PC-style interrupt controllers. Most
1097	  SMP systems and many recent uniprocessor systems have one.
1098
1099	  If you have a single-CPU system with an IO-APIC, you can say Y here
1100	  to use it. If you say Y here even though your machine doesn't have
1101	  an IO-APIC, then the kernel will still run with no slowdown at all.
1102
1103config X86_LOCAL_APIC
1104	def_bool y
1105	depends on X86_64 || SMP || X86_UP_APIC || PCI_MSI
1106	select IRQ_DOMAIN_HIERARCHY
1107
1108config ACPI_MADT_WAKEUP
1109	def_bool y
1110	depends on X86_64
1111	depends on ACPI
1112	depends on SMP
1113	depends on X86_LOCAL_APIC
1114
1115config X86_IO_APIC
1116	def_bool y
1117	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1118
1119config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1120	bool "Reroute for broken boot IRQs"
1121	depends on X86_IO_APIC
1122	help
1123	  This option enables a workaround that fixes a source of
1124	  spurious interrupts. This is recommended when threaded
1125	  interrupt handling is used on systems where the generation of
1126	  superfluous "boot interrupts" cannot be disabled.
1127
1128	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1129	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1130	  kernel does during interrupt handling). On chipsets where this
1131	  boot IRQ generation cannot be disabled, this workaround keeps
1132	  the original IRQ line masked so that only the equivalent "boot
1133	  IRQ" is delivered to the CPUs. The workaround also tells the
1134	  kernel to set up the IRQ handler on the boot IRQ line. In this
1135	  way only one interrupt is delivered to the kernel. Otherwise
1136	  the spurious second interrupt may cause the kernel to bring
1137	  down (vital) interrupt lines.
1138
1139	  Only affects "broken" chipsets. Interrupt sharing may be
1140	  increased on these systems.
1141
1142config X86_MCE
1143	bool "Machine Check / overheating reporting"
1144	select GENERIC_ALLOCATOR
1145	default y
1146	help
1147	  Machine Check support allows the processor to notify the
1148	  kernel if it detects a problem (e.g. overheating, data corruption).
1149	  The action the kernel takes depends on the severity of the problem,
1150	  ranging from warning messages to halting the machine.
1151
1152config X86_MCELOG_LEGACY
1153	bool "Support for deprecated /dev/mcelog character device"
1154	depends on X86_MCE
1155	help
1156	  Enable support for /dev/mcelog which is needed by the old mcelog
1157	  userspace logging daemon. Consider switching to the new generation
1158	  rasdaemon solution.
1159
1160config X86_MCE_INTEL
1161	def_bool y
1162	prompt "Intel MCE features"
1163	depends on X86_MCE && X86_LOCAL_APIC
1164	help
1165	  Additional support for intel specific MCE features such as
1166	  the thermal monitor.
1167
1168config X86_MCE_AMD
1169	def_bool y
1170	prompt "AMD MCE features"
1171	depends on X86_MCE && X86_LOCAL_APIC
1172	help
1173	  Additional support for AMD specific MCE features such as
1174	  the DRAM Error Threshold.
1175
1176config X86_ANCIENT_MCE
1177	bool "Support for old Pentium 5 / WinChip machine checks"
1178	depends on X86_32 && X86_MCE
1179	help
1180	  Include support for machine check handling on old Pentium 5 or WinChip
1181	  systems. These typically need to be enabled explicitly on the command
1182	  line.
1183
1184config X86_MCE_THRESHOLD
1185	depends on X86_MCE_AMD || X86_MCE_INTEL
1186	def_bool y
1187
1188config X86_MCE_INJECT
1189	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1190	tristate "Machine check injector support"
1191	help
1192	  Provide support for injecting machine checks for testing purposes.
1193	  If you don't know what a machine check is and you don't do kernel
1194	  QA it is safe to say n.
1195
1196source "arch/x86/events/Kconfig"
1197
1198config X86_LEGACY_VM86
1199	bool "Legacy VM86 support"
1200	depends on X86_32
1201	help
1202	  This option allows user programs to put the CPU into V8086
1203	  mode, which is an 80286-era approximation of 16-bit real mode.
1204
1205	  Some very old versions of X and/or vbetool require this option
1206	  for user mode setting.  Similarly, DOSEMU will use it if
1207	  available to accelerate real mode DOS programs.  However, any
1208	  recent version of DOSEMU, X, or vbetool should be fully
1209	  functional even without kernel VM86 support, as they will all
1210	  fall back to software emulation. Nevertheless, if you are using
1211	  a 16-bit DOS program where 16-bit performance matters, vm86
1212	  mode might be faster than emulation and you might want to
1213	  enable this option.
1214
1215	  Note that any app that works on a 64-bit kernel is unlikely to
1216	  need this option, as 64-bit kernels don't, and can't, support
1217	  V8086 mode. This option is also unrelated to 16-bit protected
1218	  mode and is not needed to run most 16-bit programs under Wine.
1219
1220	  Enabling this option increases the complexity of the kernel
1221	  and slows down exception handling a tiny bit.
1222
1223	  If unsure, say N here.
1224
1225config VM86
1226	bool
1227	default X86_LEGACY_VM86
1228
1229config X86_16BIT
1230	bool "Enable support for 16-bit segments" if EXPERT
1231	default y
1232	depends on MODIFY_LDT_SYSCALL
1233	help
1234	  This option is required by programs like Wine to run 16-bit
1235	  protected mode legacy code on x86 processors.  Disabling
1236	  this option saves about 300 bytes on i386, or around 6K text
1237	  plus 16K runtime memory on x86-64,
1238
1239config X86_ESPFIX32
1240	def_bool y
1241	depends on X86_16BIT && X86_32
1242
1243config X86_ESPFIX64
1244	def_bool y
1245	depends on X86_16BIT && X86_64
1246
1247config X86_VSYSCALL_EMULATION
1248	bool "Enable vsyscall emulation" if EXPERT
1249	default y
1250	depends on X86_64
1251	help
1252	  This enables emulation of the legacy vsyscall page.  Disabling
1253	  it is roughly equivalent to booting with vsyscall=none, except
1254	  that it will also disable the helpful warning if a program
1255	  tries to use a vsyscall.  With this option set to N, offending
1256	  programs will just segfault, citing addresses of the form
1257	  0xffffffffff600?00.
1258
1259	  This option is required by many programs built before 2013, and
1260	  care should be used even with newer programs if set to N.
1261
1262	  Disabling this option saves about 7K of kernel size and
1263	  possibly 4K of additional runtime pagetable memory.
1264
1265config X86_IOPL_IOPERM
1266	bool "IOPERM and IOPL Emulation"
1267	default y
1268	help
1269	  This enables the ioperm() and iopl() syscalls which are necessary
1270	  for legacy applications.
1271
1272	  Legacy IOPL support is an overbroad mechanism which allows user
1273	  space aside of accessing all 65536 I/O ports also to disable
1274	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1275	  capabilities and permission from potentially active security
1276	  modules.
1277
1278	  The emulation restricts the functionality of the syscall to
1279	  only allowing the full range I/O port access, but prevents the
1280	  ability to disable interrupts from user space which would be
1281	  granted if the hardware IOPL mechanism would be used.
1282
1283config TOSHIBA
1284	tristate "Toshiba Laptop support"
1285	depends on X86_32
1286	help
1287	  This adds a driver to safely access the System Management Mode of
1288	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1289	  not work on models with a Phoenix BIOS. The System Management Mode
1290	  is used to set the BIOS and power saving options on Toshiba portables.
1291
1292	  For information on utilities to make use of this driver see the
1293	  Toshiba Linux utilities web site at:
1294	  <http://www.buzzard.org.uk/toshiba/>.
1295
1296	  Say Y if you intend to run this kernel on a Toshiba portable.
1297	  Say N otherwise.
1298
1299config X86_REBOOTFIXUPS
1300	bool "Enable X86 board specific fixups for reboot"
1301	depends on X86_32
1302	help
1303	  This enables chipset and/or board specific fixups to be done
1304	  in order to get reboot to work correctly. This is only needed on
1305	  some combinations of hardware and BIOS. The symptom, for which
1306	  this config is intended, is when reboot ends with a stalled/hung
1307	  system.
1308
1309	  Currently, the only fixup is for the Geode machines using
1310	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1311
1312	  Say Y if you want to enable the fixup. Currently, it's safe to
1313	  enable this option even if you don't need it.
1314	  Say N otherwise.
1315
1316config MICROCODE
1317	def_bool y
1318	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1319	select CRYPTO_LIB_SHA256 if CPU_SUP_AMD
1320
1321config MICROCODE_INITRD32
1322	def_bool y
1323	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1324
1325config MICROCODE_LATE_LOADING
1326	bool "Late microcode loading (DANGEROUS)"
1327	default n
1328	depends on MICROCODE && SMP
1329	help
1330	  Loading microcode late, when the system is up and executing instructions
1331	  is a tricky business and should be avoided if possible. Just the sequence
1332	  of synchronizing all cores and SMT threads is one fragile dance which does
1333	  not guarantee that cores might not softlock after the loading. Therefore,
1334	  use this at your own risk. Late loading taints the kernel unless the
1335	  microcode header indicates that it is safe for late loading via the
1336	  minimal revision check. This minimal revision check can be enforced on
1337	  the kernel command line with "microcode.minrev=Y".
1338
1339config MICROCODE_LATE_FORCE_MINREV
1340	bool "Enforce late microcode loading minimal revision check"
1341	default n
1342	depends on MICROCODE_LATE_LOADING
1343	help
1344	  To prevent that users load microcode late which modifies already
1345	  in use features, newer microcode patches have a minimum revision field
1346	  in the microcode header, which tells the kernel which minimum
1347	  revision must be active in the CPU to safely load that new microcode
1348	  late into the running system. If disabled the check will not
1349	  be enforced but the kernel will be tainted when the minimal
1350	  revision check fails.
1351
1352	  This minimal revision check can also be controlled via the
1353	  "microcode.minrev" parameter on the kernel command line.
1354
1355	  If unsure say Y.
1356
1357config X86_MSR
1358	tristate "/dev/cpu/*/msr - Model-specific register support"
1359	help
1360	  This device gives privileged processes access to the x86
1361	  Model-Specific Registers (MSRs).  It is a character device with
1362	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1363	  MSR accesses are directed to a specific CPU on multi-processor
1364	  systems.
1365
1366config X86_CPUID
1367	tristate "/dev/cpu/*/cpuid - CPU information support"
1368	help
1369	  This device gives processes access to the x86 CPUID instruction to
1370	  be executed on a specific processor.  It is a character device
1371	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1372	  /dev/cpu/31/cpuid.
1373
1374config HIGHMEM4G
1375	bool "High Memory Support"
1376	depends on X86_32
1377	help
1378	  Linux can use up to 4 Gigabytes of physical memory on x86 systems.
1379	  However, the address space of 32-bit x86 processors is only 4
1380	  Gigabytes large. That means that, if you have a large amount of
1381	  physical memory, not all of it can be "permanently mapped" by the
1382	  kernel. The physical memory that's not permanently mapped is called
1383	  "high memory".
1384
1385	  If you are compiling a kernel which will never run on a machine with
1386	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1387	  choice and suitable for most users). This will result in a "3GB/1GB"
1388	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1389	  space and the remaining part of the 4GB virtual memory space is used
1390	  by the kernel to permanently map as much physical memory as
1391	  possible.
1392
1393	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1394	  answer "Y" here.
1395
1396	  If unsure, say N.
1397
1398choice
1399	prompt "Memory split" if EXPERT
1400	default VMSPLIT_3G
1401	depends on X86_32
1402	help
1403	  Select the desired split between kernel and user memory.
1404
1405	  If the address range available to the kernel is less than the
1406	  physical memory installed, the remaining memory will be available
1407	  as "high memory". Accessing high memory is a little more costly
1408	  than low memory, as it needs to be mapped into the kernel first.
1409	  Note that increasing the kernel address space limits the range
1410	  available to user programs, making the address space there
1411	  tighter.  Selecting anything other than the default 3G/1G split
1412	  will also likely make your kernel incompatible with binary-only
1413	  kernel modules.
1414
1415	  If you are not absolutely sure what you are doing, leave this
1416	  option alone!
1417
1418	config VMSPLIT_3G
1419		bool "3G/1G user/kernel split"
1420	config VMSPLIT_3G_OPT
1421		depends on !X86_PAE
1422		bool "3G/1G user/kernel split (for full 1G low memory)"
1423	config VMSPLIT_2G
1424		bool "2G/2G user/kernel split"
1425	config VMSPLIT_2G_OPT
1426		depends on !X86_PAE
1427		bool "2G/2G user/kernel split (for full 2G low memory)"
1428	config VMSPLIT_1G
1429		bool "1G/3G user/kernel split"
1430endchoice
1431
1432config PAGE_OFFSET
1433	hex
1434	default 0xB0000000 if VMSPLIT_3G_OPT
1435	default 0x80000000 if VMSPLIT_2G
1436	default 0x78000000 if VMSPLIT_2G_OPT
1437	default 0x40000000 if VMSPLIT_1G
1438	default 0xC0000000
1439	depends on X86_32
1440
1441config HIGHMEM
1442	def_bool HIGHMEM4G
1443
1444config X86_PAE
1445	bool "PAE (Physical Address Extension) Support"
1446	depends on X86_32 && X86_HAVE_PAE
1447	select PHYS_ADDR_T_64BIT
1448	help
1449	  PAE is required for NX support, and furthermore enables
1450	  larger swapspace support for non-overcommit purposes. It
1451	  has the cost of more pagetable lookup overhead, and also
1452	  consumes more pagetable space per process.
1453
1454config X86_5LEVEL
1455	bool "Enable 5-level page tables support"
1456	default y
1457	select DYNAMIC_MEMORY_LAYOUT
1458	select SPARSEMEM_VMEMMAP
1459	depends on X86_64
1460	help
1461	  5-level paging enables access to larger address space:
1462	  up to 128 PiB of virtual address space and 4 PiB of
1463	  physical address space.
1464
1465	  It will be supported by future Intel CPUs.
1466
1467	  A kernel with the option enabled can be booted on machines that
1468	  support 4- or 5-level paging.
1469
1470	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1471	  information.
1472
1473	  Say N if unsure.
1474
1475config X86_DIRECT_GBPAGES
1476	def_bool y
1477	depends on X86_64
1478	help
1479	  Certain kernel features effectively disable kernel
1480	  linear 1 GB mappings (even if the CPU otherwise
1481	  supports them), so don't confuse the user by printing
1482	  that we have them enabled.
1483
1484config X86_CPA_STATISTICS
1485	bool "Enable statistic for Change Page Attribute"
1486	depends on DEBUG_FS
1487	help
1488	  Expose statistics about the Change Page Attribute mechanism, which
1489	  helps to determine the effectiveness of preserving large and huge
1490	  page mappings when mapping protections are changed.
1491
1492config X86_MEM_ENCRYPT
1493	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1494	select DYNAMIC_PHYSICAL_MASK
1495	def_bool n
1496
1497config AMD_MEM_ENCRYPT
1498	bool "AMD Secure Memory Encryption (SME) support"
1499	depends on X86_64 && CPU_SUP_AMD
1500	depends on EFI_STUB
1501	select DMA_COHERENT_POOL
1502	select ARCH_USE_MEMREMAP_PROT
1503	select INSTRUCTION_DECODER
1504	select ARCH_HAS_CC_PLATFORM
1505	select X86_MEM_ENCRYPT
1506	select UNACCEPTED_MEMORY
1507	select CRYPTO_LIB_AESGCM
1508	help
1509	  Say yes to enable support for the encryption of system memory.
1510	  This requires an AMD processor that supports Secure Memory
1511	  Encryption (SME).
1512
1513# Common NUMA Features
1514config NUMA
1515	bool "NUMA Memory Allocation and Scheduler Support"
1516	depends on SMP
1517	depends on X86_64
1518	select USE_PERCPU_NUMA_NODE_ID
1519	select OF_NUMA if OF
1520	help
1521	  Enable NUMA (Non-Uniform Memory Access) support.
1522
1523	  The kernel will try to allocate memory used by a CPU on the
1524	  local memory controller of the CPU and add some more
1525	  NUMA awareness to the kernel.
1526
1527	  For 64-bit this is recommended if the system is Intel Core i7
1528	  (or later), AMD Opteron, or EM64T NUMA.
1529
1530	  Otherwise, you should say N.
1531
1532config AMD_NUMA
1533	def_bool y
1534	prompt "Old style AMD Opteron NUMA detection"
1535	depends on X86_64 && NUMA && PCI
1536	help
1537	  Enable AMD NUMA node topology detection.  You should say Y here if
1538	  you have a multi processor AMD system. This uses an old method to
1539	  read the NUMA configuration directly from the builtin Northbridge
1540	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1541	  which also takes priority if both are compiled in.
1542
1543config X86_64_ACPI_NUMA
1544	def_bool y
1545	prompt "ACPI NUMA detection"
1546	depends on X86_64 && NUMA && ACPI && PCI
1547	select ACPI_NUMA
1548	help
1549	  Enable ACPI SRAT based node topology detection.
1550
1551config NODES_SHIFT
1552	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1553	range 1 10
1554	default "10" if MAXSMP
1555	default "6" if X86_64
1556	default "3"
1557	depends on NUMA
1558	help
1559	  Specify the maximum number of NUMA Nodes available on the target
1560	  system.  Increases memory reserved to accommodate various tables.
1561
1562config ARCH_FLATMEM_ENABLE
1563	def_bool y
1564	depends on X86_32 && !NUMA
1565
1566config ARCH_SPARSEMEM_ENABLE
1567	def_bool y
1568	depends on X86_64 || NUMA || X86_32
1569	select SPARSEMEM_STATIC if X86_32
1570	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1571
1572config ARCH_SPARSEMEM_DEFAULT
1573	def_bool X86_64 || (NUMA && X86_32)
1574
1575config ARCH_SELECT_MEMORY_MODEL
1576	def_bool y
1577	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1578
1579config ARCH_MEMORY_PROBE
1580	bool "Enable sysfs memory/probe interface"
1581	depends on MEMORY_HOTPLUG
1582	help
1583	  This option enables a sysfs memory/probe interface for testing.
1584	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1585	  If you are unsure how to answer this question, answer N.
1586
1587config ARCH_PROC_KCORE_TEXT
1588	def_bool y
1589	depends on X86_64 && PROC_KCORE
1590
1591config ILLEGAL_POINTER_VALUE
1592	hex
1593	default 0 if X86_32
1594	default 0xdead000000000000 if X86_64
1595
1596config X86_PMEM_LEGACY_DEVICE
1597	bool
1598
1599config X86_PMEM_LEGACY
1600	tristate "Support non-standard NVDIMMs and ADR protected memory"
1601	depends on PHYS_ADDR_T_64BIT
1602	depends on BLK_DEV
1603	select X86_PMEM_LEGACY_DEVICE
1604	select NUMA_KEEP_MEMINFO if NUMA
1605	select LIBNVDIMM
1606	help
1607	  Treat memory marked using the non-standard e820 type of 12 as used
1608	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1609	  The kernel will offer these regions to the 'pmem' driver so
1610	  they can be used for persistent storage.
1611
1612	  Say Y if unsure.
1613
1614config X86_CHECK_BIOS_CORRUPTION
1615	bool "Check for low memory corruption"
1616	help
1617	  Periodically check for memory corruption in low memory, which
1618	  is suspected to be caused by BIOS.  Even when enabled in the
1619	  configuration, it is disabled at runtime.  Enable it by
1620	  setting "memory_corruption_check=1" on the kernel command
1621	  line.  By default it scans the low 64k of memory every 60
1622	  seconds; see the memory_corruption_check_size and
1623	  memory_corruption_check_period parameters in
1624	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1625
1626	  When enabled with the default parameters, this option has
1627	  almost no overhead, as it reserves a relatively small amount
1628	  of memory and scans it infrequently.  It both detects corruption
1629	  and prevents it from affecting the running system.
1630
1631	  It is, however, intended as a diagnostic tool; if repeatable
1632	  BIOS-originated corruption always affects the same memory,
1633	  you can use memmap= to prevent the kernel from using that
1634	  memory.
1635
1636config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1637	bool "Set the default setting of memory_corruption_check"
1638	depends on X86_CHECK_BIOS_CORRUPTION
1639	default y
1640	help
1641	  Set whether the default state of memory_corruption_check is
1642	  on or off.
1643
1644config MATH_EMULATION
1645	bool
1646	depends on MODIFY_LDT_SYSCALL
1647	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1648	help
1649	  Linux can emulate a math coprocessor (used for floating point
1650	  operations) if you don't have one. 486DX and Pentium processors have
1651	  a math coprocessor built in, 486SX and 386 do not, unless you added
1652	  a 487DX or 387, respectively. (The messages during boot time can
1653	  give you some hints here ["man dmesg"].) Everyone needs either a
1654	  coprocessor or this emulation.
1655
1656	  If you don't have a math coprocessor, you need to say Y here; if you
1657	  say Y here even though you have a coprocessor, the coprocessor will
1658	  be used nevertheless. (This behavior can be changed with the kernel
1659	  command line option "no387", which comes handy if your coprocessor
1660	  is broken. Try "man bootparam" or see the documentation of your boot
1661	  loader (lilo or loadlin) about how to pass options to the kernel at
1662	  boot time.) This means that it is a good idea to say Y here if you
1663	  intend to use this kernel on different machines.
1664
1665	  More information about the internals of the Linux math coprocessor
1666	  emulation can be found in <file:arch/x86/math-emu/README>.
1667
1668	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1669	  kernel, it won't hurt.
1670
1671config MTRR
1672	def_bool y
1673	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1674	help
1675	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1676	  the Memory Type Range Registers (MTRRs) may be used to control
1677	  processor access to memory ranges. This is most useful if you have
1678	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1679	  allows bus write transfers to be combined into a larger transfer
1680	  before bursting over the PCI/AGP bus. This can increase performance
1681	  of image write operations 2.5 times or more. Saying Y here creates a
1682	  /proc/mtrr file which may be used to manipulate your processor's
1683	  MTRRs. Typically the X server should use this.
1684
1685	  This code has a reasonably generic interface so that similar
1686	  control registers on other processors can be easily supported
1687	  as well:
1688
1689	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1690	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1691	  these, the ARRs are used to emulate the MTRRs.
1692	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1693	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1694	  write-combining. All of these processors are supported by this code
1695	  and it makes sense to say Y here if you have one of them.
1696
1697	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1698	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1699	  can lead to all sorts of problems, so it's good to say Y here.
1700
1701	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1702	  just add about 9 KB to your kernel.
1703
1704	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1705
1706config MTRR_SANITIZER
1707	def_bool y
1708	prompt "MTRR cleanup support"
1709	depends on MTRR
1710	help
1711	  Convert MTRR layout from continuous to discrete, so X drivers can
1712	  add writeback entries.
1713
1714	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1715	  The largest mtrr entry size for a continuous block can be set with
1716	  mtrr_chunk_size.
1717
1718	  If unsure, say Y.
1719
1720config MTRR_SANITIZER_ENABLE_DEFAULT
1721	int "MTRR cleanup enable value (0-1)"
1722	range 0 1
1723	default "0"
1724	depends on MTRR_SANITIZER
1725	help
1726	  Enable mtrr cleanup default value
1727
1728config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1729	int "MTRR cleanup spare reg num (0-7)"
1730	range 0 7
1731	default "1"
1732	depends on MTRR_SANITIZER
1733	help
1734	  mtrr cleanup spare entries default, it can be changed via
1735	  mtrr_spare_reg_nr=N on the kernel command line.
1736
1737config X86_PAT
1738	def_bool y
1739	prompt "x86 PAT support" if EXPERT
1740	depends on MTRR
1741	select ARCH_USES_PG_ARCH_2
1742	help
1743	  Use PAT attributes to setup page level cache control.
1744
1745	  PATs are the modern equivalents of MTRRs and are much more
1746	  flexible than MTRRs.
1747
1748	  Say N here if you see bootup problems (boot crash, boot hang,
1749	  spontaneous reboots) or a non-working video driver.
1750
1751	  If unsure, say Y.
1752
1753config X86_UMIP
1754	def_bool y
1755	prompt "User Mode Instruction Prevention" if EXPERT
1756	help
1757	  User Mode Instruction Prevention (UMIP) is a security feature in
1758	  some x86 processors. If enabled, a general protection fault is
1759	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1760	  executed in user mode. These instructions unnecessarily expose
1761	  information about the hardware state.
1762
1763	  The vast majority of applications do not use these instructions.
1764	  For the very few that do, software emulation is provided in
1765	  specific cases in protected and virtual-8086 modes. Emulated
1766	  results are dummy.
1767
1768config CC_HAS_IBT
1769	# GCC >= 9 and binutils >= 2.29
1770	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1771	# Clang/LLVM >= 14
1772	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1773	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1774	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1775		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1776		  $(as-instr,endbr64)
1777
1778config X86_CET
1779	def_bool n
1780	help
1781	  CET features configured (Shadow stack or IBT)
1782
1783config X86_KERNEL_IBT
1784	prompt "Indirect Branch Tracking"
1785	def_bool y
1786	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1787	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1788	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1789	select OBJTOOL
1790	select X86_CET
1791	help
1792	  Build the kernel with support for Indirect Branch Tracking, a
1793	  hardware support course-grain forward-edge Control Flow Integrity
1794	  protection. It enforces that all indirect calls must land on
1795	  an ENDBR instruction, as such, the compiler will instrument the
1796	  code with them to make this happen.
1797
1798	  In addition to building the kernel with IBT, seal all functions that
1799	  are not indirect call targets, avoiding them ever becoming one.
1800
1801	  This requires LTO like objtool runs and will slow down the build. It
1802	  does significantly reduce the number of ENDBR instructions in the
1803	  kernel image.
1804
1805config X86_INTEL_MEMORY_PROTECTION_KEYS
1806	prompt "Memory Protection Keys"
1807	def_bool y
1808	# Note: only available in 64-bit mode
1809	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1810	select ARCH_USES_HIGH_VMA_FLAGS
1811	select ARCH_HAS_PKEYS
1812	help
1813	  Memory Protection Keys provides a mechanism for enforcing
1814	  page-based protections, but without requiring modification of the
1815	  page tables when an application changes protection domains.
1816
1817	  For details, see Documentation/core-api/protection-keys.rst
1818
1819	  If unsure, say y.
1820
1821config ARCH_PKEY_BITS
1822	int
1823	default 4
1824
1825choice
1826	prompt "TSX enable mode"
1827	depends on CPU_SUP_INTEL
1828	default X86_INTEL_TSX_MODE_OFF
1829	help
1830	  Intel's TSX (Transactional Synchronization Extensions) feature
1831	  allows to optimize locking protocols through lock elision which
1832	  can lead to a noticeable performance boost.
1833
1834	  On the other hand it has been shown that TSX can be exploited
1835	  to form side channel attacks (e.g. TAA) and chances are there
1836	  will be more of those attacks discovered in the future.
1837
1838	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1839	  might override this decision by tsx=on the command line parameter.
1840	  Even with TSX enabled, the kernel will attempt to enable the best
1841	  possible TAA mitigation setting depending on the microcode available
1842	  for the particular machine.
1843
1844	  This option allows to set the default tsx mode between tsx=on, =off
1845	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1846	  details.
1847
1848	  Say off if not sure, auto if TSX is in use but it should be used on safe
1849	  platforms or on if TSX is in use and the security aspect of tsx is not
1850	  relevant.
1851
1852config X86_INTEL_TSX_MODE_OFF
1853	bool "off"
1854	help
1855	  TSX is disabled if possible - equals to tsx=off command line parameter.
1856
1857config X86_INTEL_TSX_MODE_ON
1858	bool "on"
1859	help
1860	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1861	  line parameter.
1862
1863config X86_INTEL_TSX_MODE_AUTO
1864	bool "auto"
1865	help
1866	  TSX is enabled on TSX capable HW that is believed to be safe against
1867	  side channel attacks- equals the tsx=auto command line parameter.
1868endchoice
1869
1870config X86_SGX
1871	bool "Software Guard eXtensions (SGX)"
1872	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1873	depends on CRYPTO=y
1874	depends on CRYPTO_SHA256=y
1875	select MMU_NOTIFIER
1876	select NUMA_KEEP_MEMINFO if NUMA
1877	select XARRAY_MULTI
1878	help
1879	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1880	  that can be used by applications to set aside private regions of code
1881	  and data, referred to as enclaves. An enclave's private memory can
1882	  only be accessed by code running within the enclave. Accesses from
1883	  outside the enclave, including other enclaves, are disallowed by
1884	  hardware.
1885
1886	  If unsure, say N.
1887
1888config X86_USER_SHADOW_STACK
1889	bool "X86 userspace shadow stack"
1890	depends on AS_WRUSS
1891	depends on X86_64
1892	select ARCH_USES_HIGH_VMA_FLAGS
1893	select ARCH_HAS_USER_SHADOW_STACK
1894	select X86_CET
1895	help
1896	  Shadow stack protection is a hardware feature that detects function
1897	  return address corruption.  This helps mitigate ROP attacks.
1898	  Applications must be enabled to use it, and old userspace does not
1899	  get protection "for free".
1900
1901	  CPUs supporting shadow stacks were first released in 2020.
1902
1903	  See Documentation/arch/x86/shstk.rst for more information.
1904
1905	  If unsure, say N.
1906
1907config INTEL_TDX_HOST
1908	bool "Intel Trust Domain Extensions (TDX) host support"
1909	depends on CPU_SUP_INTEL
1910	depends on X86_64
1911	depends on KVM_INTEL
1912	depends on X86_X2APIC
1913	select ARCH_KEEP_MEMBLOCK
1914	depends on CONTIG_ALLOC
1915	depends on !KEXEC_CORE
1916	depends on X86_MCE
1917	help
1918	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1919	  host and certain physical attacks.  This option enables necessary TDX
1920	  support in the host kernel to run confidential VMs.
1921
1922	  If unsure, say N.
1923
1924config EFI
1925	bool "EFI runtime service support"
1926	depends on ACPI
1927	select UCS2_STRING
1928	select EFI_RUNTIME_WRAPPERS
1929	select ARCH_USE_MEMREMAP_PROT
1930	select EFI_RUNTIME_MAP if KEXEC_CORE
1931	help
1932	  This enables the kernel to use EFI runtime services that are
1933	  available (such as the EFI variable services).
1934
1935	  This option is only useful on systems that have EFI firmware.
1936	  In addition, you should use the latest ELILO loader available
1937	  at <http://elilo.sourceforge.net> in order to take advantage
1938	  of EFI runtime services. However, even with this option, the
1939	  resultant kernel should continue to boot on existing non-EFI
1940	  platforms.
1941
1942config EFI_STUB
1943	bool "EFI stub support"
1944	depends on EFI
1945	select RELOCATABLE
1946	help
1947	  This kernel feature allows a bzImage to be loaded directly
1948	  by EFI firmware without the use of a bootloader.
1949
1950	  See Documentation/admin-guide/efi-stub.rst for more information.
1951
1952config EFI_HANDOVER_PROTOCOL
1953	bool "EFI handover protocol (DEPRECATED)"
1954	depends on EFI_STUB
1955	default y
1956	help
1957	  Select this in order to include support for the deprecated EFI
1958	  handover protocol, which defines alternative entry points into the
1959	  EFI stub.  This is a practice that has no basis in the UEFI
1960	  specification, and requires a priori knowledge on the part of the
1961	  bootloader about Linux/x86 specific ways of passing the command line
1962	  and initrd, and where in memory those assets may be loaded.
1963
1964	  If in doubt, say Y. Even though the corresponding support is not
1965	  present in upstream GRUB or other bootloaders, most distros build
1966	  GRUB with numerous downstream patches applied, and may rely on the
1967	  handover protocol as as result.
1968
1969config EFI_MIXED
1970	bool "EFI mixed-mode support"
1971	depends on EFI_STUB && X86_64
1972	help
1973	  Enabling this feature allows a 64-bit kernel to be booted
1974	  on a 32-bit firmware, provided that your CPU supports 64-bit
1975	  mode.
1976
1977	  Note that it is not possible to boot a mixed-mode enabled
1978	  kernel via the EFI boot stub - a bootloader that supports
1979	  the EFI handover protocol must be used.
1980
1981	  If unsure, say N.
1982
1983config EFI_RUNTIME_MAP
1984	bool "Export EFI runtime maps to sysfs" if EXPERT
1985	depends on EFI
1986	help
1987	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
1988	  That memory map is required by the 2nd kernel to set up EFI virtual
1989	  mappings after kexec, but can also be used for debugging purposes.
1990
1991	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
1992
1993source "kernel/Kconfig.hz"
1994
1995config ARCH_SUPPORTS_KEXEC
1996	def_bool y
1997
1998config ARCH_SUPPORTS_KEXEC_FILE
1999	def_bool X86_64
2000
2001config ARCH_SELECTS_KEXEC_FILE
2002	def_bool y
2003	depends on KEXEC_FILE
2004	select HAVE_IMA_KEXEC if IMA
2005
2006config ARCH_SUPPORTS_KEXEC_PURGATORY
2007	def_bool y
2008
2009config ARCH_SUPPORTS_KEXEC_SIG
2010	def_bool y
2011
2012config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2013	def_bool y
2014
2015config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2016	def_bool y
2017
2018config ARCH_SUPPORTS_KEXEC_JUMP
2019	def_bool y
2020
2021config ARCH_SUPPORTS_CRASH_DUMP
2022	def_bool X86_64 || (X86_32 && HIGHMEM)
2023
2024config ARCH_DEFAULT_CRASH_DUMP
2025	def_bool y
2026
2027config ARCH_SUPPORTS_CRASH_HOTPLUG
2028	def_bool y
2029
2030config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2031	def_bool CRASH_RESERVE
2032
2033config PHYSICAL_START
2034	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2035	default "0x1000000"
2036	help
2037	  This gives the physical address where the kernel is loaded.
2038
2039	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2040	  will decompress itself to above physical address and run from there.
2041	  Otherwise, bzImage will run from the address where it has been loaded
2042	  by the boot loader. The only exception is if it is loaded below the
2043	  above physical address, in which case it will relocate itself there.
2044
2045	  In normal kdump cases one does not have to set/change this option
2046	  as now bzImage can be compiled as a completely relocatable image
2047	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2048	  address. This option is mainly useful for the folks who don't want
2049	  to use a bzImage for capturing the crash dump and want to use a
2050	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2051	  to be specifically compiled to run from a specific memory area
2052	  (normally a reserved region) and this option comes handy.
2053
2054	  So if you are using bzImage for capturing the crash dump,
2055	  leave the value here unchanged to 0x1000000 and set
2056	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2057	  for capturing the crash dump change this value to start of
2058	  the reserved region.  In other words, it can be set based on
2059	  the "X" value as specified in the "crashkernel=YM@XM"
2060	  command line boot parameter passed to the panic-ed
2061	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2062	  for more details about crash dumps.
2063
2064	  Usage of bzImage for capturing the crash dump is recommended as
2065	  one does not have to build two kernels. Same kernel can be used
2066	  as production kernel and capture kernel. Above option should have
2067	  gone away after relocatable bzImage support is introduced. But it
2068	  is present because there are users out there who continue to use
2069	  vmlinux for dump capture. This option should go away down the
2070	  line.
2071
2072	  Don't change this unless you know what you are doing.
2073
2074config RELOCATABLE
2075	bool "Build a relocatable kernel"
2076	default y
2077	help
2078	  This builds a kernel image that retains relocation information
2079	  so it can be loaded someplace besides the default 1MB.
2080	  The relocations tend to make the kernel binary about 10% larger,
2081	  but are discarded at runtime.
2082
2083	  One use is for the kexec on panic case where the recovery kernel
2084	  must live at a different physical address than the primary
2085	  kernel.
2086
2087	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2088	  it has been loaded at and the compile time physical address
2089	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2090
2091config RANDOMIZE_BASE
2092	bool "Randomize the address of the kernel image (KASLR)"
2093	depends on RELOCATABLE
2094	default y
2095	help
2096	  In support of Kernel Address Space Layout Randomization (KASLR),
2097	  this randomizes the physical address at which the kernel image
2098	  is decompressed and the virtual address where the kernel
2099	  image is mapped, as a security feature that deters exploit
2100	  attempts relying on knowledge of the location of kernel
2101	  code internals.
2102
2103	  On 64-bit, the kernel physical and virtual addresses are
2104	  randomized separately. The physical address will be anywhere
2105	  between 16MB and the top of physical memory (up to 64TB). The
2106	  virtual address will be randomized from 16MB up to 1GB (9 bits
2107	  of entropy). Note that this also reduces the memory space
2108	  available to kernel modules from 1.5GB to 1GB.
2109
2110	  On 32-bit, the kernel physical and virtual addresses are
2111	  randomized together. They will be randomized from 16MB up to
2112	  512MB (8 bits of entropy).
2113
2114	  Entropy is generated using the RDRAND instruction if it is
2115	  supported. If RDTSC is supported, its value is mixed into
2116	  the entropy pool as well. If neither RDRAND nor RDTSC are
2117	  supported, then entropy is read from the i8254 timer. The
2118	  usable entropy is limited by the kernel being built using
2119	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2120	  minimum of 2MB. As a result, only 10 bits of entropy are
2121	  theoretically possible, but the implementations are further
2122	  limited due to memory layouts.
2123
2124	  If unsure, say Y.
2125
2126# Relocation on x86 needs some additional build support
2127config X86_NEED_RELOCS
2128	def_bool y
2129	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2130
2131config PHYSICAL_ALIGN
2132	hex "Alignment value to which kernel should be aligned"
2133	default "0x200000"
2134	range 0x2000 0x1000000 if X86_32
2135	range 0x200000 0x1000000 if X86_64
2136	help
2137	  This value puts the alignment restrictions on physical address
2138	  where kernel is loaded and run from. Kernel is compiled for an
2139	  address which meets above alignment restriction.
2140
2141	  If bootloader loads the kernel at a non-aligned address and
2142	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2143	  address aligned to above value and run from there.
2144
2145	  If bootloader loads the kernel at a non-aligned address and
2146	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2147	  load address and decompress itself to the address it has been
2148	  compiled for and run from there. The address for which kernel is
2149	  compiled already meets above alignment restrictions. Hence the
2150	  end result is that kernel runs from a physical address meeting
2151	  above alignment restrictions.
2152
2153	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2154	  this value must be a multiple of 0x200000.
2155
2156	  Don't change this unless you know what you are doing.
2157
2158config DYNAMIC_MEMORY_LAYOUT
2159	bool
2160	help
2161	  This option makes base addresses of vmalloc and vmemmap as well as
2162	  __PAGE_OFFSET movable during boot.
2163
2164config RANDOMIZE_MEMORY
2165	bool "Randomize the kernel memory sections"
2166	depends on X86_64
2167	depends on RANDOMIZE_BASE
2168	select DYNAMIC_MEMORY_LAYOUT
2169	default RANDOMIZE_BASE
2170	help
2171	  Randomizes the base virtual address of kernel memory sections
2172	  (physical memory mapping, vmalloc & vmemmap). This security feature
2173	  makes exploits relying on predictable memory locations less reliable.
2174
2175	  The order of allocations remains unchanged. Entropy is generated in
2176	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2177	  configuration have in average 30,000 different possible virtual
2178	  addresses for each memory section.
2179
2180	  If unsure, say Y.
2181
2182config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2183	hex "Physical memory mapping padding" if EXPERT
2184	depends on RANDOMIZE_MEMORY
2185	default "0xa" if MEMORY_HOTPLUG
2186	default "0x0"
2187	range 0x1 0x40 if MEMORY_HOTPLUG
2188	range 0x0 0x40
2189	help
2190	  Define the padding in terabytes added to the existing physical
2191	  memory size during kernel memory randomization. It is useful
2192	  for memory hotplug support but reduces the entropy available for
2193	  address randomization.
2194
2195	  If unsure, leave at the default value.
2196
2197config ADDRESS_MASKING
2198	bool "Linear Address Masking support"
2199	depends on X86_64
2200	depends on COMPILE_TEST || !CPU_MITIGATIONS # wait for LASS
2201	help
2202	  Linear Address Masking (LAM) modifies the checking that is applied
2203	  to 64-bit linear addresses, allowing software to use of the
2204	  untranslated address bits for metadata.
2205
2206	  The capability can be used for efficient address sanitizers (ASAN)
2207	  implementation and for optimizations in JITs.
2208
2209config HOTPLUG_CPU
2210	def_bool y
2211	depends on SMP
2212
2213config COMPAT_VDSO
2214	def_bool n
2215	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2216	depends on COMPAT_32
2217	help
2218	  Certain buggy versions of glibc will crash if they are
2219	  presented with a 32-bit vDSO that is not mapped at the address
2220	  indicated in its segment table.
2221
2222	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2223	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2224	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2225	  the only released version with the bug, but OpenSUSE 9
2226	  contains a buggy "glibc 2.3.2".
2227
2228	  The symptom of the bug is that everything crashes on startup, saying:
2229	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2230
2231	  Saying Y here changes the default value of the vdso32 boot
2232	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2233	  This works around the glibc bug but hurts performance.
2234
2235	  If unsure, say N: if you are compiling your own kernel, you
2236	  are unlikely to be using a buggy version of glibc.
2237
2238choice
2239	prompt "vsyscall table for legacy applications"
2240	depends on X86_64
2241	default LEGACY_VSYSCALL_XONLY
2242	help
2243	  Legacy user code that does not know how to find the vDSO expects
2244	  to be able to issue three syscalls by calling fixed addresses in
2245	  kernel space. Since this location is not randomized with ASLR,
2246	  it can be used to assist security vulnerability exploitation.
2247
2248	  This setting can be changed at boot time via the kernel command
2249	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2250	  is deprecated and can only be enabled using the kernel command
2251	  line.
2252
2253	  On a system with recent enough glibc (2.14 or newer) and no
2254	  static binaries, you can say None without a performance penalty
2255	  to improve security.
2256
2257	  If unsure, select "Emulate execution only".
2258
2259	config LEGACY_VSYSCALL_XONLY
2260		bool "Emulate execution only"
2261		help
2262		  The kernel traps and emulates calls into the fixed vsyscall
2263		  address mapping and does not allow reads.  This
2264		  configuration is recommended when userspace might use the
2265		  legacy vsyscall area but support for legacy binary
2266		  instrumentation of legacy code is not needed.  It mitigates
2267		  certain uses of the vsyscall area as an ASLR-bypassing
2268		  buffer.
2269
2270	config LEGACY_VSYSCALL_NONE
2271		bool "None"
2272		help
2273		  There will be no vsyscall mapping at all. This will
2274		  eliminate any risk of ASLR bypass due to the vsyscall
2275		  fixed address mapping. Attempts to use the vsyscalls
2276		  will be reported to dmesg, so that either old or
2277		  malicious userspace programs can be identified.
2278
2279endchoice
2280
2281config CMDLINE_BOOL
2282	bool "Built-in kernel command line"
2283	help
2284	  Allow for specifying boot arguments to the kernel at
2285	  build time.  On some systems (e.g. embedded ones), it is
2286	  necessary or convenient to provide some or all of the
2287	  kernel boot arguments with the kernel itself (that is,
2288	  to not rely on the boot loader to provide them.)
2289
2290	  To compile command line arguments into the kernel,
2291	  set this option to 'Y', then fill in the
2292	  boot arguments in CONFIG_CMDLINE.
2293
2294	  Systems with fully functional boot loaders (i.e. non-embedded)
2295	  should leave this option set to 'N'.
2296
2297config CMDLINE
2298	string "Built-in kernel command string"
2299	depends on CMDLINE_BOOL
2300	default ""
2301	help
2302	  Enter arguments here that should be compiled into the kernel
2303	  image and used at boot time.  If the boot loader provides a
2304	  command line at boot time, it is appended to this string to
2305	  form the full kernel command line, when the system boots.
2306
2307	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2308	  change this behavior.
2309
2310	  In most cases, the command line (whether built-in or provided
2311	  by the boot loader) should specify the device for the root
2312	  file system.
2313
2314config CMDLINE_OVERRIDE
2315	bool "Built-in command line overrides boot loader arguments"
2316	depends on CMDLINE_BOOL && CMDLINE != ""
2317	help
2318	  Set this option to 'Y' to have the kernel ignore the boot loader
2319	  command line, and use ONLY the built-in command line.
2320
2321	  This is used to work around broken boot loaders.  This should
2322	  be set to 'N' under normal conditions.
2323
2324config MODIFY_LDT_SYSCALL
2325	bool "Enable the LDT (local descriptor table)" if EXPERT
2326	default y
2327	help
2328	  Linux can allow user programs to install a per-process x86
2329	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2330	  call.  This is required to run 16-bit or segmented code such as
2331	  DOSEMU or some Wine programs.  It is also used by some very old
2332	  threading libraries.
2333
2334	  Enabling this feature adds a small amount of overhead to
2335	  context switches and increases the low-level kernel attack
2336	  surface.  Disabling it removes the modify_ldt(2) system call.
2337
2338	  Saying 'N' here may make sense for embedded or server kernels.
2339
2340config STRICT_SIGALTSTACK_SIZE
2341	bool "Enforce strict size checking for sigaltstack"
2342	depends on DYNAMIC_SIGFRAME
2343	help
2344	  For historical reasons MINSIGSTKSZ is a constant which became
2345	  already too small with AVX512 support. Add a mechanism to
2346	  enforce strict checking of the sigaltstack size against the
2347	  real size of the FPU frame. This option enables the check
2348	  by default. It can also be controlled via the kernel command
2349	  line option 'strict_sas_size' independent of this config
2350	  switch. Enabling it might break existing applications which
2351	  allocate a too small sigaltstack but 'work' because they
2352	  never get a signal delivered.
2353
2354	  Say 'N' unless you want to really enforce this check.
2355
2356config CFI_AUTO_DEFAULT
2357	bool "Attempt to use FineIBT by default at boot time"
2358	depends on FINEIBT
2359	default y
2360	help
2361	  Attempt to use FineIBT by default at boot time. If enabled,
2362	  this is the same as booting with "cfi=auto". If disabled,
2363	  this is the same as booting with "cfi=kcfi".
2364
2365source "kernel/livepatch/Kconfig"
2366
2367config X86_BUS_LOCK_DETECT
2368	bool "Split Lock Detect and Bus Lock Detect support"
2369	depends on CPU_SUP_INTEL || CPU_SUP_AMD
2370	default y
2371	help
2372	  Enable Split Lock Detect and Bus Lock Detect functionalities.
2373	  See <file:Documentation/arch/x86/buslock.rst> for more information.
2374
2375endmenu
2376
2377config CC_HAS_NAMED_AS
2378	def_bool $(success,echo 'int __seg_fs fs; int __seg_gs gs;' | $(CC) -x c - -S -o /dev/null)
2379	depends on CC_IS_GCC
2380
2381#
2382# -fsanitize=kernel-address (KASAN) and -fsanitize=thread (KCSAN)
2383# are incompatible with named address spaces with GCC < 13.3
2384# (see GCC PR sanitizer/111736 and also PR sanitizer/115172).
2385#
2386
2387config CC_HAS_NAMED_AS_FIXED_SANITIZERS
2388	def_bool y
2389	depends on !(KASAN || KCSAN) || GCC_VERSION >= 130300
2390	depends on !(UBSAN_BOOL && KASAN) || GCC_VERSION >= 140200
2391
2392config USE_X86_SEG_SUPPORT
2393	def_bool CC_HAS_NAMED_AS
2394	depends on CC_HAS_NAMED_AS_FIXED_SANITIZERS
2395
2396config CC_HAS_SLS
2397	def_bool $(cc-option,-mharden-sls=all)
2398
2399config CC_HAS_RETURN_THUNK
2400	def_bool $(cc-option,-mfunction-return=thunk-extern)
2401
2402config CC_HAS_ENTRY_PADDING
2403	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2404
2405config CC_HAS_KCFI_ARITY
2406	def_bool $(cc-option,-fsanitize=kcfi -fsanitize-kcfi-arity)
2407	depends on CC_IS_CLANG && !RUST
2408
2409config FUNCTION_PADDING_CFI
2410	int
2411	default 59 if FUNCTION_ALIGNMENT_64B
2412	default 27 if FUNCTION_ALIGNMENT_32B
2413	default 11 if FUNCTION_ALIGNMENT_16B
2414	default  3 if FUNCTION_ALIGNMENT_8B
2415	default  0
2416
2417# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2418# except Kconfig can't do arithmetic :/
2419config FUNCTION_PADDING_BYTES
2420	int
2421	default FUNCTION_PADDING_CFI if CFI_CLANG
2422	default FUNCTION_ALIGNMENT
2423
2424config CALL_PADDING
2425	def_bool n
2426	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2427	select FUNCTION_ALIGNMENT_16B
2428
2429config FINEIBT
2430	def_bool y
2431	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
2432	select CALL_PADDING
2433
2434config FINEIBT_BHI
2435	def_bool y
2436	depends on FINEIBT && CC_HAS_KCFI_ARITY
2437
2438config HAVE_CALL_THUNKS
2439	def_bool y
2440	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2441
2442config CALL_THUNKS
2443	def_bool n
2444	select CALL_PADDING
2445
2446config PREFIX_SYMBOLS
2447	def_bool y
2448	depends on CALL_PADDING && !CFI_CLANG
2449
2450menuconfig CPU_MITIGATIONS
2451	bool "Mitigations for CPU vulnerabilities"
2452	default y
2453	help
2454	  Say Y here to enable options which enable mitigations for hardware
2455	  vulnerabilities (usually related to speculative execution).
2456	  Mitigations can be disabled or restricted to SMT systems at runtime
2457	  via the "mitigations" kernel parameter.
2458
2459	  If you say N, all mitigations will be disabled.  This CANNOT be
2460	  overridden at runtime.
2461
2462	  Say 'Y', unless you really know what you are doing.
2463
2464if CPU_MITIGATIONS
2465
2466config MITIGATION_PAGE_TABLE_ISOLATION
2467	bool "Remove the kernel mapping in user mode"
2468	default y
2469	depends on (X86_64 || X86_PAE)
2470	help
2471	  This feature reduces the number of hardware side channels by
2472	  ensuring that the majority of kernel addresses are not mapped
2473	  into userspace.
2474
2475	  See Documentation/arch/x86/pti.rst for more details.
2476
2477config MITIGATION_RETPOLINE
2478	bool "Avoid speculative indirect branches in kernel"
2479	select OBJTOOL if HAVE_OBJTOOL
2480	default y
2481	help
2482	  Compile kernel with the retpoline compiler options to guard against
2483	  kernel-to-user data leaks by avoiding speculative indirect
2484	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2485	  support for full protection. The kernel may run slower.
2486
2487config MITIGATION_RETHUNK
2488	bool "Enable return-thunks"
2489	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2490	select OBJTOOL if HAVE_OBJTOOL
2491	default y if X86_64
2492	help
2493	  Compile the kernel with the return-thunks compiler option to guard
2494	  against kernel-to-user data leaks by avoiding return speculation.
2495	  Requires a compiler with -mfunction-return=thunk-extern
2496	  support for full protection. The kernel may run slower.
2497
2498config MITIGATION_UNRET_ENTRY
2499	bool "Enable UNRET on kernel entry"
2500	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2501	default y
2502	help
2503	  Compile the kernel with support for the retbleed=unret mitigation.
2504
2505config MITIGATION_CALL_DEPTH_TRACKING
2506	bool "Mitigate RSB underflow with call depth tracking"
2507	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2508	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2509	select CALL_THUNKS
2510	default y
2511	help
2512	  Compile the kernel with call depth tracking to mitigate the Intel
2513	  SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
2514	  by default and needs to be enabled on the kernel command line via the
2515	  retbleed=stuff option. For non-affected systems the overhead of this
2516	  option is marginal as the call depth tracking is using run-time
2517	  generated call thunks in a compiler generated padding area and call
2518	  patching. This increases text size by ~5%. For non affected systems
2519	  this space is unused. On affected SKL systems this results in a
2520	  significant performance gain over the IBRS mitigation.
2521
2522config CALL_THUNKS_DEBUG
2523	bool "Enable call thunks and call depth tracking debugging"
2524	depends on MITIGATION_CALL_DEPTH_TRACKING
2525	select FUNCTION_ALIGNMENT_32B
2526	default n
2527	help
2528	  Enable call/ret counters for imbalance detection and build in
2529	  a noisy dmesg about callthunks generation and call patching for
2530	  trouble shooting. The debug prints need to be enabled on the
2531	  kernel command line with 'debug-callthunks'.
2532	  Only enable this when you are debugging call thunks as this
2533	  creates a noticeable runtime overhead. If unsure say N.
2534
2535config MITIGATION_IBPB_ENTRY
2536	bool "Enable IBPB on kernel entry"
2537	depends on CPU_SUP_AMD && X86_64
2538	default y
2539	help
2540	  Compile the kernel with support for the retbleed=ibpb and
2541	  spec_rstack_overflow={ibpb,ibpb-vmexit} mitigations.
2542
2543config MITIGATION_IBRS_ENTRY
2544	bool "Enable IBRS on kernel entry"
2545	depends on CPU_SUP_INTEL && X86_64
2546	default y
2547	help
2548	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2549	  This mitigates both spectre_v2 and retbleed at great cost to
2550	  performance.
2551
2552config MITIGATION_SRSO
2553	bool "Mitigate speculative RAS overflow on AMD"
2554	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2555	default y
2556	help
2557	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2558
2559config MITIGATION_SLS
2560	bool "Mitigate Straight-Line-Speculation"
2561	depends on CC_HAS_SLS && X86_64
2562	select OBJTOOL if HAVE_OBJTOOL
2563	default n
2564	help
2565	  Compile the kernel with straight-line-speculation options to guard
2566	  against straight line speculation. The kernel image might be slightly
2567	  larger.
2568
2569config MITIGATION_GDS
2570	bool "Mitigate Gather Data Sampling"
2571	depends on CPU_SUP_INTEL
2572	default y
2573	help
2574	  Enable mitigation for Gather Data Sampling (GDS). GDS is a hardware
2575	  vulnerability which allows unprivileged speculative access to data
2576	  which was previously stored in vector registers. The attacker uses gather
2577	  instructions to infer the stale vector register data.
2578
2579config MITIGATION_RFDS
2580	bool "RFDS Mitigation"
2581	depends on CPU_SUP_INTEL
2582	default y
2583	help
2584	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2585	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2586	  allows unprivileged speculative access to stale data previously
2587	  stored in floating point, vector and integer registers.
2588	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2589
2590config MITIGATION_SPECTRE_BHI
2591	bool "Mitigate Spectre-BHB (Branch History Injection)"
2592	depends on CPU_SUP_INTEL
2593	default y
2594	help
2595	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2596	  where the branch history buffer is poisoned to speculatively steer
2597	  indirect branches.
2598	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2599
2600config MITIGATION_MDS
2601	bool "Mitigate Microarchitectural Data Sampling (MDS) hardware bug"
2602	depends on CPU_SUP_INTEL
2603	default y
2604	help
2605	  Enable mitigation for Microarchitectural Data Sampling (MDS). MDS is
2606	  a hardware vulnerability which allows unprivileged speculative access
2607	  to data which is available in various CPU internal buffers.
2608	  See also <file:Documentation/admin-guide/hw-vuln/mds.rst>
2609
2610config MITIGATION_TAA
2611	bool "Mitigate TSX Asynchronous Abort (TAA) hardware bug"
2612	depends on CPU_SUP_INTEL
2613	default y
2614	help
2615	  Enable mitigation for TSX Asynchronous Abort (TAA). TAA is a hardware
2616	  vulnerability that allows unprivileged speculative access to data
2617	  which is available in various CPU internal buffers by using
2618	  asynchronous aborts within an Intel TSX transactional region.
2619	  See also <file:Documentation/admin-guide/hw-vuln/tsx_async_abort.rst>
2620
2621config MITIGATION_MMIO_STALE_DATA
2622	bool "Mitigate MMIO Stale Data hardware bug"
2623	depends on CPU_SUP_INTEL
2624	default y
2625	help
2626	  Enable mitigation for MMIO Stale Data hardware bugs.  Processor MMIO
2627	  Stale Data Vulnerabilities are a class of memory-mapped I/O (MMIO)
2628	  vulnerabilities that can expose data. The vulnerabilities require the
2629	  attacker to have access to MMIO.
2630	  See also
2631	  <file:Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst>
2632
2633config MITIGATION_L1TF
2634	bool "Mitigate L1 Terminal Fault (L1TF) hardware bug"
2635	depends on CPU_SUP_INTEL
2636	default y
2637	help
2638	  Mitigate L1 Terminal Fault (L1TF) hardware bug. L1 Terminal Fault is a
2639	  hardware vulnerability which allows unprivileged speculative access to data
2640	  available in the Level 1 Data Cache.
2641	  See <file:Documentation/admin-guide/hw-vuln/l1tf.rst
2642
2643config MITIGATION_RETBLEED
2644	bool "Mitigate RETBleed hardware bug"
2645	depends on (CPU_SUP_INTEL && MITIGATION_SPECTRE_V2) || MITIGATION_UNRET_ENTRY || MITIGATION_IBPB_ENTRY
2646	default y
2647	help
2648	  Enable mitigation for RETBleed (Arbitrary Speculative Code Execution
2649	  with Return Instructions) vulnerability.  RETBleed is a speculative
2650	  execution attack which takes advantage of microarchitectural behavior
2651	  in many modern microprocessors, similar to Spectre v2. An
2652	  unprivileged attacker can use these flaws to bypass conventional
2653	  memory security restrictions to gain read access to privileged memory
2654	  that would otherwise be inaccessible.
2655
2656config MITIGATION_SPECTRE_V1
2657	bool "Mitigate SPECTRE V1 hardware bug"
2658	default y
2659	help
2660	  Enable mitigation for Spectre V1 (Bounds Check Bypass). Spectre V1 is a
2661	  class of side channel attacks that takes advantage of speculative
2662	  execution that bypasses conditional branch instructions used for
2663	  memory access bounds check.
2664	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2665
2666config MITIGATION_SPECTRE_V2
2667	bool "Mitigate SPECTRE V2 hardware bug"
2668	default y
2669	help
2670	  Enable mitigation for Spectre V2 (Branch Target Injection). Spectre
2671	  V2 is a class of side channel attacks that takes advantage of
2672	  indirect branch predictors inside the processor. In Spectre variant 2
2673	  attacks, the attacker can steer speculative indirect branches in the
2674	  victim to gadget code by poisoning the branch target buffer of a CPU
2675	  used for predicting indirect branch addresses.
2676	  See also <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2677
2678config MITIGATION_SRBDS
2679	bool "Mitigate Special Register Buffer Data Sampling (SRBDS) hardware bug"
2680	depends on CPU_SUP_INTEL
2681	default y
2682	help
2683	  Enable mitigation for Special Register Buffer Data Sampling (SRBDS).
2684	  SRBDS is a hardware vulnerability that allows Microarchitectural Data
2685	  Sampling (MDS) techniques to infer values returned from special
2686	  register accesses. An unprivileged user can extract values returned
2687	  from RDRAND and RDSEED executed on another core or sibling thread
2688	  using MDS techniques.
2689	  See also
2690	  <file:Documentation/admin-guide/hw-vuln/special-register-buffer-data-sampling.rst>
2691
2692config MITIGATION_SSB
2693	bool "Mitigate Speculative Store Bypass (SSB) hardware bug"
2694	default y
2695	help
2696	  Enable mitigation for Speculative Store Bypass (SSB). SSB is a
2697	  hardware security vulnerability and its exploitation takes advantage
2698	  of speculative execution in a similar way to the Meltdown and Spectre
2699	  security vulnerabilities.
2700
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
2905config PCI_OLPC
2906	def_bool y
2907	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2908
2909config PCI_XEN
2910	def_bool y
2911	depends on PCI && XEN
2912
2913config MMCONF_FAM10H
2914	def_bool y
2915	depends on X86_64 && PCI_MMCONFIG && ACPI
2916
2917config PCI_CNB20LE_QUIRK
2918	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2919	depends on PCI
2920	help
2921	  Read the PCI windows out of the CNB20LE host bridge. This allows
2922	  PCI hotplug to work on systems with the CNB20LE chipset which do
2923	  not have ACPI.
2924
2925	  There's no public spec for this chipset, and this functionality
2926	  is known to be incomplete.
2927
2928	  You should say N unless you know you need this.
2929
2930config ISA_BUS
2931	bool "ISA bus support on modern systems" if EXPERT
2932	help
2933	  Expose ISA bus device drivers and options available for selection and
2934	  configuration. Enable this option if your target machine has an ISA
2935	  bus. ISA is an older system, displaced by PCI and newer bus
2936	  architectures -- if your target machine is modern, it probably does
2937	  not have an ISA bus.
2938
2939	  If unsure, say N.
2940
2941# x86_64 have no ISA slots, but can have ISA-style DMA.
2942config ISA_DMA_API
2943	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2944	default y
2945	help
2946	  Enables ISA-style DMA support for devices requiring such controllers.
2947	  If unsure, say Y.
2948
2949if X86_32
2950
2951config ISA
2952	bool "ISA support"
2953	help
2954	  Find out whether you have ISA slots on your motherboard.  ISA is the
2955	  name of a bus system, i.e. the way the CPU talks to the other stuff
2956	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2957	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2958	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2959
2960config SCx200
2961	tristate "NatSemi SCx200 support"
2962	help
2963	  This provides basic support for National Semiconductor's
2964	  (now AMD's) Geode processors.  The driver probes for the
2965	  PCI-IDs of several on-chip devices, so its a good dependency
2966	  for other scx200_* drivers.
2967
2968	  If compiled as a module, the driver is named scx200.
2969
2970config SCx200HR_TIMER
2971	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2972	depends on SCx200
2973	default y
2974	help
2975	  This driver provides a clocksource built upon the on-chip
2976	  27MHz high-resolution timer.  Its also a workaround for
2977	  NSC Geode SC-1100's buggy TSC, which loses time when the
2978	  processor goes idle (as is done by the scheduler).  The
2979	  other workaround is idle=poll boot option.
2980
2981config OLPC
2982	bool "One Laptop Per Child support"
2983	depends on !X86_PAE
2984	select GPIOLIB
2985	select OF
2986	select OF_PROMTREE
2987	select IRQ_DOMAIN
2988	select OLPC_EC
2989	help
2990	  Add support for detecting the unique features of the OLPC
2991	  XO hardware.
2992
2993config OLPC_XO1_PM
2994	bool "OLPC XO-1 Power Management"
2995	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2996	help
2997	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2998
2999config OLPC_XO1_RTC
3000	bool "OLPC XO-1 Real Time Clock"
3001	depends on OLPC_XO1_PM && RTC_DRV_CMOS
3002	help
3003	  Add support for the XO-1 real time clock, which can be used as a
3004	  programmable wakeup source.
3005
3006config OLPC_XO1_SCI
3007	bool "OLPC XO-1 SCI extras"
3008	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
3009	depends on INPUT=y
3010	select POWER_SUPPLY
3011	help
3012	  Add support for SCI-based features of the OLPC XO-1 laptop:
3013	   - EC-driven system wakeups
3014	   - Power button
3015	   - Ebook switch
3016	   - Lid switch
3017	   - AC adapter status updates
3018	   - Battery status updates
3019
3020config OLPC_XO15_SCI
3021	bool "OLPC XO-1.5 SCI extras"
3022	depends on OLPC && ACPI
3023	select POWER_SUPPLY
3024	help
3025	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
3026	   - EC-driven system wakeups
3027	   - AC adapter status updates
3028	   - Battery status updates
3029
3030config GEODE_COMMON
3031	bool
3032
3033config ALIX
3034	bool "PCEngines ALIX System Support (LED setup)"
3035	select GPIOLIB
3036	select GEODE_COMMON
3037	help
3038	  This option enables system support for the PCEngines ALIX.
3039	  At present this just sets up LEDs for GPIO control on
3040	  ALIX2/3/6 boards.  However, other system specific setup should
3041	  get added here.
3042
3043	  Note: You must still enable the drivers for GPIO and LED support
3044	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
3045
3046	  Note: You have to set alix.force=1 for boards with Award BIOS.
3047
3048config NET5501
3049	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
3050	select GPIOLIB
3051	select GEODE_COMMON
3052	help
3053	  This option enables system support for the Soekris Engineering net5501.
3054
3055config GEOS
3056	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3057	select GPIOLIB
3058	select GEODE_COMMON
3059	depends on DMI
3060	help
3061	  This option enables system support for the Traverse Technologies GEOS.
3062
3063config TS5500
3064	bool "Technologic Systems TS-5500 platform support"
3065	depends on MELAN
3066	select CHECK_SIGNATURE
3067	select NEW_LEDS
3068	select LEDS_CLASS
3069	help
3070	  This option enables system support for the Technologic Systems TS-5500.
3071
3072endif # X86_32
3073
3074config AMD_NB
3075	def_bool y
3076	depends on AMD_NODE
3077
3078config AMD_NODE
3079	def_bool y
3080	depends on CPU_SUP_AMD && PCI
3081
3082endmenu
3083
3084menu "Binary Emulations"
3085
3086config IA32_EMULATION
3087	bool "IA32 Emulation"
3088	depends on X86_64
3089	select ARCH_WANT_OLD_COMPAT_IPC
3090	select BINFMT_ELF
3091	select COMPAT_OLD_SIGACTION
3092	help
3093	  Include code to run legacy 32-bit programs under a
3094	  64-bit kernel. You should likely turn this on, unless you're
3095	  100% sure that you don't have any 32-bit programs left.
3096
3097config IA32_EMULATION_DEFAULT_DISABLED
3098	bool "IA32 emulation disabled by default"
3099	default n
3100	depends on IA32_EMULATION
3101	help
3102	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3103	  processes and access to 32-bit syscalls. If unsure, leave it to its
3104	  default value.
3105
3106config X86_X32_ABI
3107	bool "x32 ABI for 64-bit mode"
3108	depends on X86_64
3109	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3110	# compressed debug sections to x86_x32 properly:
3111	# https://github.com/ClangBuiltLinux/linux/issues/514
3112	# https://github.com/ClangBuiltLinux/linux/issues/1141
3113	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3114	help
3115	  Include code to run binaries for the x32 native 32-bit ABI
3116	  for 64-bit processors.  An x32 process gets access to the
3117	  full 64-bit register file and wide data path while leaving
3118	  pointers at 32 bits for smaller memory footprint.
3119
3120config COMPAT_32
3121	def_bool y
3122	depends on IA32_EMULATION || X86_32
3123	select HAVE_UID16
3124	select OLD_SIGSUSPEND3
3125
3126config COMPAT
3127	def_bool y
3128	depends on IA32_EMULATION || X86_X32_ABI
3129
3130config COMPAT_FOR_U64_ALIGNMENT
3131	def_bool y
3132	depends on COMPAT
3133
3134endmenu
3135
3136config HAVE_ATOMIC_IOMAP
3137	def_bool y
3138	depends on X86_32
3139
3140source "arch/x86/kvm/Kconfig"
3141
3142source "arch/x86/Kconfig.cpufeatures"
3143
3144source "arch/x86/Kconfig.assembler"
3145