xref: /linux/arch/x86/Kconfig (revision 82ba0ff7bf0483d962e592017bef659ae022d754)
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_USE_CMPXCHG_LOCKREF
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
39config FORCE_DYNAMIC_FTRACE
40	def_bool y
41	depends on X86_32
42	depends on FUNCTION_TRACER
43	select DYNAMIC_FTRACE
44	help
45	  We keep the static function tracing (!DYNAMIC_FTRACE) around
46	  in order to test the non static function tracing in the
47	  generic code, as other architectures still use it. But we
48	  only need to keep it around for x86_64. No need to keep it
49	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
50#
51# Arch settings
52#
53# ( Note that options that are marked 'if X86_64' could in principle be
54#   ported to 32-bit as well. )
55#
56config X86
57	def_bool y
58	#
59	# Note: keep this list sorted alphabetically
60	#
61	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
62	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
63	select ARCH_32BIT_OFF_T			if X86_32
64	select ARCH_CLOCKSOURCE_INIT
65	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
66	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
67	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
68	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
69	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
70	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
71	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
72	select ARCH_HAS_CACHE_LINE_SIZE
73	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
74	select ARCH_HAS_CPU_FINALIZE_INIT
75	select ARCH_HAS_CURRENT_STACK_POINTER
76	select ARCH_HAS_DEBUG_VIRTUAL
77	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
78	select ARCH_HAS_DEVMEM_IS_ALLOWED
79	select ARCH_HAS_EARLY_DEBUG		if KGDB
80	select ARCH_HAS_ELF_RANDOMIZE
81	select ARCH_HAS_FAST_MULTIPLIER
82	select ARCH_HAS_FORTIFY_SOURCE
83	select ARCH_HAS_GCOV_PROFILE_ALL
84	select ARCH_HAS_KCOV			if X86_64
85	select ARCH_HAS_MEM_ENCRYPT
86	select ARCH_HAS_MEMBARRIER_SYNC_CORE
87	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
88	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
89	select ARCH_HAS_PMEM_API		if X86_64
90	select ARCH_HAS_PTE_DEVMAP		if X86_64
91	select ARCH_HAS_PTE_SPECIAL
92	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
93	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
94	select ARCH_HAS_COPY_MC			if X86_64
95	select ARCH_HAS_SET_MEMORY
96	select ARCH_HAS_SET_DIRECT_MAP
97	select ARCH_HAS_STRICT_KERNEL_RWX
98	select ARCH_HAS_STRICT_MODULE_RWX
99	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
100	select ARCH_HAS_SYSCALL_WRAPPER
101	select ARCH_HAS_UBSAN_SANITIZE_ALL
102	select ARCH_HAS_DEBUG_WX
103	select ARCH_HAS_ZONE_DMA_SET if EXPERT
104	select ARCH_HAVE_NMI_SAFE_CMPXCHG
105	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
106	select ARCH_MIGHT_HAVE_PC_PARPORT
107	select ARCH_MIGHT_HAVE_PC_SERIO
108	select ARCH_STACKWALK
109	select ARCH_SUPPORTS_ACPI
110	select ARCH_SUPPORTS_ATOMIC_RMW
111	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
112	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
113	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
114	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
115	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
116	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
117	select ARCH_SUPPORTS_LTO_CLANG
118	select ARCH_SUPPORTS_LTO_CLANG_THIN
119	select ARCH_USE_BUILTIN_BSWAP
120	select ARCH_USE_MEMTEST
121	select ARCH_USE_QUEUED_RWLOCKS
122	select ARCH_USE_QUEUED_SPINLOCKS
123	select ARCH_USE_SYM_ANNOTATIONS
124	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
125	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
126	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
127	select ARCH_WANTS_NO_INSTR
128	select ARCH_WANT_GENERAL_HUGETLB
129	select ARCH_WANT_HUGE_PMD_SHARE
130	select ARCH_WANT_LD_ORPHAN_WARN
131	select ARCH_WANT_OPTIMIZE_VMEMMAP	if X86_64
132	select ARCH_WANTS_THP_SWAP		if X86_64
133	select ARCH_HAS_PARANOID_L1D_FLUSH
134	select BUILDTIME_TABLE_SORT
135	select CLKEVT_I8253
136	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
137	select CLOCKSOURCE_WATCHDOG
138	# Word-size accesses may read uninitialized data past the trailing \0
139	# in strings and cause false KMSAN reports.
140	select DCACHE_WORD_ACCESS		if !KMSAN
141	select DYNAMIC_SIGFRAME
142	select EDAC_ATOMIC_SCRUB
143	select EDAC_SUPPORT
144	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
145	select GENERIC_CLOCKEVENTS_MIN_ADJUST
146	select GENERIC_CMOS_UPDATE
147	select GENERIC_CPU_AUTOPROBE
148	select GENERIC_CPU_VULNERABILITIES
149	select GENERIC_EARLY_IOREMAP
150	select GENERIC_ENTRY
151	select GENERIC_IOMAP
152	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
153	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
154	select GENERIC_IRQ_MIGRATION		if SMP
155	select GENERIC_IRQ_PROBE
156	select GENERIC_IRQ_RESERVATION_MODE
157	select GENERIC_IRQ_SHOW
158	select GENERIC_PENDING_IRQ		if SMP
159	select GENERIC_PTDUMP
160	select GENERIC_SMP_IDLE_THREAD
161	select GENERIC_TIME_VSYSCALL
162	select GENERIC_GETTIMEOFDAY
163	select GENERIC_VDSO_TIME_NS
164	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
165	select HARDIRQS_SW_RESEND
166	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
167	select HAS_IOPORT
168	select HAVE_ACPI_APEI			if ACPI
169	select HAVE_ACPI_APEI_NMI		if ACPI
170	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
171	select HAVE_ARCH_AUDITSYSCALL
172	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
173	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
174	select HAVE_ARCH_JUMP_LABEL
175	select HAVE_ARCH_JUMP_LABEL_RELATIVE
176	select HAVE_ARCH_KASAN			if X86_64
177	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
178	select HAVE_ARCH_KFENCE
179	select HAVE_ARCH_KMSAN			if X86_64
180	select HAVE_ARCH_KGDB
181	select HAVE_ARCH_MMAP_RND_BITS		if MMU
182	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
183	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
184	select HAVE_ARCH_PREL32_RELOCATIONS
185	select HAVE_ARCH_SECCOMP_FILTER
186	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
187	select HAVE_ARCH_STACKLEAK
188	select HAVE_ARCH_TRACEHOOK
189	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
190	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
191	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
192	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
193	select HAVE_ARCH_VMAP_STACK		if X86_64
194	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
195	select HAVE_ARCH_WITHIN_STACK_FRAMES
196	select HAVE_ASM_MODVERSIONS
197	select HAVE_CMPXCHG_DOUBLE
198	select HAVE_CMPXCHG_LOCAL
199	select HAVE_CONTEXT_TRACKING_USER		if X86_64
200	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
201	select HAVE_C_RECORDMCOUNT
202	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
203	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
204	select HAVE_BUILDTIME_MCOUNT_SORT
205	select HAVE_DEBUG_KMEMLEAK
206	select HAVE_DMA_CONTIGUOUS
207	select HAVE_DYNAMIC_FTRACE
208	select HAVE_DYNAMIC_FTRACE_WITH_REGS
209	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
210	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
211	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
212	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
213	select HAVE_EBPF_JIT
214	select HAVE_EFFICIENT_UNALIGNED_ACCESS
215	select HAVE_EISA
216	select HAVE_EXIT_THREAD
217	select HAVE_FAST_GUP
218	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
219	select HAVE_FTRACE_MCOUNT_RECORD
220	select HAVE_FUNCTION_GRAPH_RETVAL	if HAVE_FUNCTION_GRAPH_TRACER
221	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
222	select HAVE_FUNCTION_TRACER
223	select HAVE_GCC_PLUGINS
224	select HAVE_HW_BREAKPOINT
225	select HAVE_IOREMAP_PROT
226	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
227	select HAVE_IRQ_TIME_ACCOUNTING
228	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
229	select HAVE_KERNEL_BZIP2
230	select HAVE_KERNEL_GZIP
231	select HAVE_KERNEL_LZ4
232	select HAVE_KERNEL_LZMA
233	select HAVE_KERNEL_LZO
234	select HAVE_KERNEL_XZ
235	select HAVE_KERNEL_ZSTD
236	select HAVE_KPROBES
237	select HAVE_KPROBES_ON_FTRACE
238	select HAVE_FUNCTION_ERROR_INJECTION
239	select HAVE_KRETPROBES
240	select HAVE_RETHOOK
241	select HAVE_KVM
242	select HAVE_LIVEPATCH			if X86_64
243	select HAVE_MIXED_BREAKPOINTS_REGS
244	select HAVE_MOD_ARCH_SPECIFIC
245	select HAVE_MOVE_PMD
246	select HAVE_MOVE_PUD
247	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
248	select HAVE_NMI
249	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
250	select HAVE_OBJTOOL			if X86_64
251	select HAVE_OPTPROBES
252	select HAVE_PCSPKR_PLATFORM
253	select HAVE_PERF_EVENTS
254	select HAVE_PERF_EVENTS_NMI
255	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
256	select HAVE_PCI
257	select HAVE_PERF_REGS
258	select HAVE_PERF_USER_STACK_DUMP
259	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
260	select MMU_GATHER_MERGE_VMAS
261	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
262	select HAVE_REGS_AND_STACK_ACCESS_API
263	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
264	select HAVE_FUNCTION_ARG_ACCESS_API
265	select HAVE_SETUP_PER_CPU_AREA
266	select HAVE_SOFTIRQ_ON_OWN_STACK
267	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
268	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
269	select HAVE_STATIC_CALL
270	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
271	select HAVE_PREEMPT_DYNAMIC_CALL
272	select HAVE_RSEQ
273	select HAVE_RUST			if X86_64
274	select HAVE_SYSCALL_TRACEPOINTS
275	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
276	select HAVE_UNSTABLE_SCHED_CLOCK
277	select HAVE_USER_RETURN_NOTIFIER
278	select HAVE_GENERIC_VDSO
279	select HOTPLUG_PARALLEL			if SMP && X86_64
280	select HOTPLUG_SMT			if SMP
281	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
282	select IRQ_FORCED_THREADING
283	select LOCK_MM_AND_FIND_VMA
284	select NEED_PER_CPU_EMBED_FIRST_CHUNK
285	select NEED_PER_CPU_PAGE_FIRST_CHUNK
286	select NEED_SG_DMA_LENGTH
287	select PCI_DOMAINS			if PCI
288	select PCI_LOCKLESS_CONFIG		if PCI
289	select PERF_EVENTS
290	select RTC_LIB
291	select RTC_MC146818_LIB
292	select SPARSE_IRQ
293	select SYSCTL_EXCEPTION_TRACE
294	select THREAD_INFO_IN_TASK
295	select TRACE_IRQFLAGS_SUPPORT
296	select TRACE_IRQFLAGS_NMI_SUPPORT
297	select USER_STACKTRACE_SUPPORT
298	select HAVE_ARCH_KCSAN			if X86_64
299	select PROC_PID_ARCH_STATUS		if PROC_FS
300	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
301	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
302	select FUNCTION_ALIGNMENT_4B
303	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
304	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
305
306config INSTRUCTION_DECODER
307	def_bool y
308	depends on KPROBES || PERF_EVENTS || UPROBES
309
310config OUTPUT_FORMAT
311	string
312	default "elf32-i386" if X86_32
313	default "elf64-x86-64" if X86_64
314
315config LOCKDEP_SUPPORT
316	def_bool y
317
318config STACKTRACE_SUPPORT
319	def_bool y
320
321config MMU
322	def_bool y
323
324config ARCH_MMAP_RND_BITS_MIN
325	default 28 if 64BIT
326	default 8
327
328config ARCH_MMAP_RND_BITS_MAX
329	default 32 if 64BIT
330	default 16
331
332config ARCH_MMAP_RND_COMPAT_BITS_MIN
333	default 8
334
335config ARCH_MMAP_RND_COMPAT_BITS_MAX
336	default 16
337
338config SBUS
339	bool
340
341config GENERIC_ISA_DMA
342	def_bool y
343	depends on ISA_DMA_API
344
345config GENERIC_CSUM
346	bool
347	default y if KMSAN || KASAN
348
349config GENERIC_BUG
350	def_bool y
351	depends on BUG
352	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
353
354config GENERIC_BUG_RELATIVE_POINTERS
355	bool
356
357config ARCH_MAY_HAVE_PC_FDC
358	def_bool y
359	depends on ISA_DMA_API
360
361config GENERIC_CALIBRATE_DELAY
362	def_bool y
363
364config ARCH_HAS_CPU_RELAX
365	def_bool y
366
367config ARCH_HIBERNATION_POSSIBLE
368	def_bool y
369
370config ARCH_SUSPEND_POSSIBLE
371	def_bool y
372
373config AUDIT_ARCH
374	def_bool y if X86_64
375
376config KASAN_SHADOW_OFFSET
377	hex
378	depends on KASAN
379	default 0xdffffc0000000000
380
381config HAVE_INTEL_TXT
382	def_bool y
383	depends on INTEL_IOMMU && ACPI
384
385config X86_32_SMP
386	def_bool y
387	depends on X86_32 && SMP
388
389config X86_64_SMP
390	def_bool y
391	depends on X86_64 && SMP
392
393config ARCH_SUPPORTS_UPROBES
394	def_bool y
395
396config FIX_EARLYCON_MEM
397	def_bool y
398
399config DYNAMIC_PHYSICAL_MASK
400	bool
401
402config PGTABLE_LEVELS
403	int
404	default 5 if X86_5LEVEL
405	default 4 if X86_64
406	default 3 if X86_PAE
407	default 2
408
409config CC_HAS_SANE_STACKPROTECTOR
410	bool
411	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
412	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
413	help
414	  We have to make sure stack protector is unconditionally disabled if
415	  the compiler produces broken code or if it does not let us control
416	  the segment on 32-bit kernels.
417
418menu "Processor type and features"
419
420config SMP
421	bool "Symmetric multi-processing support"
422	help
423	  This enables support for systems with more than one CPU. If you have
424	  a system with only one CPU, say N. If you have a system with more
425	  than one CPU, say Y.
426
427	  If you say N here, the kernel will run on uni- and multiprocessor
428	  machines, but will use only one CPU of a multiprocessor machine. If
429	  you say Y here, the kernel will run on many, but not all,
430	  uniprocessor machines. On a uniprocessor machine, the kernel
431	  will run faster if you say N here.
432
433	  Note that if you say Y here and choose architecture "586" or
434	  "Pentium" under "Processor family", the kernel will not work on 486
435	  architectures. Similarly, multiprocessor kernels for the "PPro"
436	  architecture may not work on all Pentium based boards.
437
438	  People using multiprocessor machines who say Y here should also say
439	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
440	  Management" code will be disabled if you say Y here.
441
442	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
443	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
444	  <http://www.tldp.org/docs.html#howto>.
445
446	  If you don't know what to do here, say N.
447
448config X86_X2APIC
449	bool "Support x2apic"
450	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
451	help
452	  This enables x2apic support on CPUs that have this feature.
453
454	  This allows 32-bit apic IDs (so it can support very large systems),
455	  and accesses the local apic via MSRs not via mmio.
456
457	  Some Intel systems circa 2022 and later are locked into x2APIC mode
458	  and can not fall back to the legacy APIC modes if SGX or TDX are
459	  enabled in the BIOS. They will boot with very reduced functionality
460	  without enabling this option.
461
462	  If you don't know what to do here, say N.
463
464config X86_MPPARSE
465	bool "Enable MPS table" if ACPI
466	default y
467	depends on X86_LOCAL_APIC
468	help
469	  For old smp systems that do not have proper acpi support. Newer systems
470	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
471
472config GOLDFISH
473	def_bool y
474	depends on X86_GOLDFISH
475
476config X86_CPU_RESCTRL
477	bool "x86 CPU resource control support"
478	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
479	select KERNFS
480	select PROC_CPU_RESCTRL		if PROC_FS
481	help
482	  Enable x86 CPU resource control support.
483
484	  Provide support for the allocation and monitoring of system resources
485	  usage by the CPU.
486
487	  Intel calls this Intel Resource Director Technology
488	  (Intel(R) RDT). More information about RDT can be found in the
489	  Intel x86 Architecture Software Developer Manual.
490
491	  AMD calls this AMD Platform Quality of Service (AMD QoS).
492	  More information about AMD QoS can be found in the AMD64 Technology
493	  Platform Quality of Service Extensions manual.
494
495	  Say N if unsure.
496
497if X86_32
498config X86_BIGSMP
499	bool "Support for big SMP systems with more than 8 CPUs"
500	depends on SMP
501	help
502	  This option is needed for the systems that have more than 8 CPUs.
503
504config X86_EXTENDED_PLATFORM
505	bool "Support for extended (non-PC) x86 platforms"
506	default y
507	help
508	  If you disable this option then the kernel will only support
509	  standard PC platforms. (which covers the vast majority of
510	  systems out there.)
511
512	  If you enable this option then you'll be able to select support
513	  for the following (non-PC) 32 bit x86 platforms:
514		Goldfish (Android emulator)
515		AMD Elan
516		RDC R-321x SoC
517		SGI 320/540 (Visual Workstation)
518		STA2X11-based (e.g. Northville)
519		Moorestown MID devices
520
521	  If you have one of these systems, or if you want to build a
522	  generic distribution kernel, say Y here - otherwise say N.
523endif # X86_32
524
525if X86_64
526config X86_EXTENDED_PLATFORM
527	bool "Support for extended (non-PC) x86 platforms"
528	default y
529	help
530	  If you disable this option then the kernel will only support
531	  standard PC platforms. (which covers the vast majority of
532	  systems out there.)
533
534	  If you enable this option then you'll be able to select support
535	  for the following (non-PC) 64 bit x86 platforms:
536		Numascale NumaChip
537		ScaleMP vSMP
538		SGI Ultraviolet
539
540	  If you have one of these systems, or if you want to build a
541	  generic distribution kernel, say Y here - otherwise say N.
542endif # X86_64
543# This is an alphabetically sorted list of 64 bit extended platforms
544# Please maintain the alphabetic order if and when there are additions
545config X86_NUMACHIP
546	bool "Numascale NumaChip"
547	depends on X86_64
548	depends on X86_EXTENDED_PLATFORM
549	depends on NUMA
550	depends on SMP
551	depends on X86_X2APIC
552	depends on PCI_MMCONFIG
553	help
554	  Adds support for Numascale NumaChip large-SMP systems. Needed to
555	  enable more than ~168 cores.
556	  If you don't have one of these, you should say N here.
557
558config X86_VSMP
559	bool "ScaleMP vSMP"
560	select HYPERVISOR_GUEST
561	select PARAVIRT
562	depends on X86_64 && PCI
563	depends on X86_EXTENDED_PLATFORM
564	depends on SMP
565	help
566	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
567	  supposed to run on these EM64T-based machines.  Only choose this option
568	  if you have one of these machines.
569
570config X86_UV
571	bool "SGI Ultraviolet"
572	depends on X86_64
573	depends on X86_EXTENDED_PLATFORM
574	depends on NUMA
575	depends on EFI
576	depends on KEXEC_CORE
577	depends on X86_X2APIC
578	depends on PCI
579	help
580	  This option is needed in order to support SGI Ultraviolet systems.
581	  If you don't have one of these, you should say N here.
582
583# Following is an alphabetically sorted list of 32 bit extended platforms
584# Please maintain the alphabetic order if and when there are additions
585
586config X86_GOLDFISH
587	bool "Goldfish (Virtual Platform)"
588	depends on X86_EXTENDED_PLATFORM
589	help
590	  Enable support for the Goldfish virtual platform used primarily
591	  for Android development. Unless you are building for the Android
592	  Goldfish emulator say N here.
593
594config X86_INTEL_CE
595	bool "CE4100 TV platform"
596	depends on PCI
597	depends on PCI_GODIRECT
598	depends on X86_IO_APIC
599	depends on X86_32
600	depends on X86_EXTENDED_PLATFORM
601	select X86_REBOOTFIXUPS
602	select OF
603	select OF_EARLY_FLATTREE
604	help
605	  Select for the Intel CE media processor (CE4100) SOC.
606	  This option compiles in support for the CE4100 SOC for settop
607	  boxes and media devices.
608
609config X86_INTEL_MID
610	bool "Intel MID platform support"
611	depends on X86_EXTENDED_PLATFORM
612	depends on X86_PLATFORM_DEVICES
613	depends on PCI
614	depends on X86_64 || (PCI_GOANY && X86_32)
615	depends on X86_IO_APIC
616	select I2C
617	select DW_APB_TIMER
618	select INTEL_SCU_PCI
619	help
620	  Select to build a kernel capable of supporting Intel MID (Mobile
621	  Internet Device) platform systems which do not have the PCI legacy
622	  interfaces. If you are building for a PC class system 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_INTEL_QUARK
628	bool "Intel Quark platform support"
629	depends on X86_32
630	depends on X86_EXTENDED_PLATFORM
631	depends on X86_PLATFORM_DEVICES
632	depends on X86_TSC
633	depends on PCI
634	depends on PCI_GOANY
635	depends on X86_IO_APIC
636	select IOSF_MBI
637	select INTEL_IMR
638	select COMMON_CLK
639	help
640	  Select to include support for Quark X1000 SoC.
641	  Say Y here if you have a Quark based system such as the Arduino
642	  compatible Intel Galileo.
643
644config X86_INTEL_LPSS
645	bool "Intel Low Power Subsystem Support"
646	depends on X86 && ACPI && PCI
647	select COMMON_CLK
648	select PINCTRL
649	select IOSF_MBI
650	help
651	  Select to build support for Intel Low Power Subsystem such as
652	  found on Intel Lynxpoint PCH. Selecting this option enables
653	  things like clock tree (common clock framework) and pincontrol
654	  which are needed by the LPSS peripheral drivers.
655
656config X86_AMD_PLATFORM_DEVICE
657	bool "AMD ACPI2Platform devices support"
658	depends on ACPI
659	select COMMON_CLK
660	select PINCTRL
661	help
662	  Select to interpret AMD specific ACPI device to platform device
663	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
664	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
665	  implemented under PINCTRL subsystem.
666
667config IOSF_MBI
668	tristate "Intel SoC IOSF Sideband support for SoC platforms"
669	depends on PCI
670	help
671	  This option enables sideband register access support for Intel SoC
672	  platforms. On these platforms the IOSF sideband is used in lieu of
673	  MSR's for some register accesses, mostly but not limited to thermal
674	  and power. Drivers may query the availability of this device to
675	  determine if they need the sideband in order to work on these
676	  platforms. The sideband is available on the following SoC products.
677	  This list is not meant to be exclusive.
678	   - BayTrail
679	   - Braswell
680	   - Quark
681
682	  You should say Y if you are running a kernel on one of these SoC's.
683
684config IOSF_MBI_DEBUG
685	bool "Enable IOSF sideband access through debugfs"
686	depends on IOSF_MBI && DEBUG_FS
687	help
688	  Select this option to expose the IOSF sideband access registers (MCR,
689	  MDR, MCRX) through debugfs to write and read register information from
690	  different units on the SoC. This is most useful for obtaining device
691	  state information for debug and analysis. As this is a general access
692	  mechanism, users of this option would have specific knowledge of the
693	  device they want to access.
694
695	  If you don't require the option or are in doubt, say N.
696
697config X86_RDC321X
698	bool "RDC R-321x SoC"
699	depends on X86_32
700	depends on X86_EXTENDED_PLATFORM
701	select M486
702	select X86_REBOOTFIXUPS
703	help
704	  This option is needed for RDC R-321x system-on-chip, also known
705	  as R-8610-(G).
706	  If you don't have one of these chips, you should say N here.
707
708config X86_32_NON_STANDARD
709	bool "Support non-standard 32-bit SMP architectures"
710	depends on X86_32 && SMP
711	depends on X86_EXTENDED_PLATFORM
712	help
713	  This option compiles in the bigsmp and STA2X11 default
714	  subarchitectures.  It is intended for a generic binary
715	  kernel. If you select them all, kernel will probe it one by
716	  one and will fallback to default.
717
718# Alphabetically sorted list of Non standard 32 bit platforms
719
720config X86_SUPPORTS_MEMORY_FAILURE
721	def_bool y
722	# MCE code calls memory_failure():
723	depends on X86_MCE
724	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
725	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
726	depends on X86_64 || !SPARSEMEM
727	select ARCH_SUPPORTS_MEMORY_FAILURE
728
729config STA2X11
730	bool "STA2X11 Companion Chip Support"
731	depends on X86_32_NON_STANDARD && PCI
732	select SWIOTLB
733	select MFD_STA2X11
734	select GPIOLIB
735	help
736	  This adds support for boards based on the STA2X11 IO-Hub,
737	  a.k.a. "ConneXt". The chip is used in place of the standard
738	  PC chipset, so all "standard" peripherals are missing. If this
739	  option is selected the kernel will still be able to boot on
740	  standard PC machines.
741
742config X86_32_IRIS
743	tristate "Eurobraille/Iris poweroff module"
744	depends on X86_32
745	help
746	  The Iris machines from EuroBraille do not have APM or ACPI support
747	  to shut themselves down properly.  A special I/O sequence is
748	  needed to do so, which is what this module does at
749	  kernel shutdown.
750
751	  This is only for Iris machines from EuroBraille.
752
753	  If unused, say N.
754
755config SCHED_OMIT_FRAME_POINTER
756	def_bool y
757	prompt "Single-depth WCHAN output"
758	depends on X86
759	help
760	  Calculate simpler /proc/<PID>/wchan values. If this option
761	  is disabled then wchan values will recurse back to the
762	  caller function. This provides more accurate wchan values,
763	  at the expense of slightly more scheduling overhead.
764
765	  If in doubt, say "Y".
766
767menuconfig HYPERVISOR_GUEST
768	bool "Linux guest support"
769	help
770	  Say Y here to enable options for running Linux under various hyper-
771	  visors. This option enables basic hypervisor detection and platform
772	  setup.
773
774	  If you say N, all options in this submenu will be skipped and
775	  disabled, and Linux guest support won't be built in.
776
777if HYPERVISOR_GUEST
778
779config PARAVIRT
780	bool "Enable paravirtualization code"
781	depends on HAVE_STATIC_CALL
782	help
783	  This changes the kernel so it can modify itself when it is run
784	  under a hypervisor, potentially improving performance significantly
785	  over full virtualization.  However, when run without a hypervisor
786	  the kernel is theoretically slower and slightly larger.
787
788config PARAVIRT_XXL
789	bool
790
791config PARAVIRT_DEBUG
792	bool "paravirt-ops debugging"
793	depends on PARAVIRT && DEBUG_KERNEL
794	help
795	  Enable to debug paravirt_ops internals.  Specifically, BUG if
796	  a paravirt_op is missing when it is called.
797
798config PARAVIRT_SPINLOCKS
799	bool "Paravirtualization layer for spinlocks"
800	depends on PARAVIRT && SMP
801	help
802	  Paravirtualized spinlocks allow a pvops backend to replace the
803	  spinlock implementation with something virtualization-friendly
804	  (for example, block the virtual CPU rather than spinning).
805
806	  It has a minimal impact on native kernels and gives a nice performance
807	  benefit on paravirtualized KVM / Xen kernels.
808
809	  If you are unsure how to answer this question, answer Y.
810
811config X86_HV_CALLBACK_VECTOR
812	def_bool n
813
814source "arch/x86/xen/Kconfig"
815
816config KVM_GUEST
817	bool "KVM Guest support (including kvmclock)"
818	depends on PARAVIRT
819	select PARAVIRT_CLOCK
820	select ARCH_CPUIDLE_HALTPOLL
821	select X86_HV_CALLBACK_VECTOR
822	default y
823	help
824	  This option enables various optimizations for running under the KVM
825	  hypervisor. It includes a paravirtualized clock, so that instead
826	  of relying on a PIT (or probably other) emulation by the
827	  underlying device model, the host provides the guest with
828	  timing infrastructure such as time of day, and system time
829
830config ARCH_CPUIDLE_HALTPOLL
831	def_bool n
832	prompt "Disable host haltpoll when loading haltpoll driver"
833	help
834	  If virtualized under KVM, disable host haltpoll.
835
836config PVH
837	bool "Support for running PVH guests"
838	help
839	  This option enables the PVH entry point for guest virtual machines
840	  as specified in the x86/HVM direct boot ABI.
841
842config PARAVIRT_TIME_ACCOUNTING
843	bool "Paravirtual steal time accounting"
844	depends on PARAVIRT
845	help
846	  Select this option to enable fine granularity task steal time
847	  accounting. Time spent executing other tasks in parallel with
848	  the current vCPU is discounted from the vCPU power. To account for
849	  that, there can be a small performance impact.
850
851	  If in doubt, say N here.
852
853config PARAVIRT_CLOCK
854	bool
855
856config JAILHOUSE_GUEST
857	bool "Jailhouse non-root cell support"
858	depends on X86_64 && PCI
859	select X86_PM_TIMER
860	help
861	  This option allows to run Linux as guest in a Jailhouse non-root
862	  cell. You can leave this option disabled if you only want to start
863	  Jailhouse and run Linux afterwards in the root cell.
864
865config ACRN_GUEST
866	bool "ACRN Guest support"
867	depends on X86_64
868	select X86_HV_CALLBACK_VECTOR
869	help
870	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
871	  a flexible, lightweight reference open-source hypervisor, built with
872	  real-time and safety-criticality in mind. It is built for embedded
873	  IOT with small footprint and real-time features. More details can be
874	  found in https://projectacrn.org/.
875
876config INTEL_TDX_GUEST
877	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
878	depends on X86_64 && CPU_SUP_INTEL
879	depends on X86_X2APIC
880	depends on EFI_STUB
881	select ARCH_HAS_CC_PLATFORM
882	select X86_MEM_ENCRYPT
883	select X86_MCE
884	select UNACCEPTED_MEMORY
885	help
886	  Support running as a guest under Intel TDX.  Without this support,
887	  the guest kernel can not boot or run under TDX.
888	  TDX includes memory encryption and integrity capabilities
889	  which protect the confidentiality and integrity of guest
890	  memory contents and CPU state. TDX guests are protected from
891	  some attacks from the VMM.
892
893endif # HYPERVISOR_GUEST
894
895source "arch/x86/Kconfig.cpu"
896
897config HPET_TIMER
898	def_bool X86_64
899	prompt "HPET Timer Support" if X86_32
900	help
901	  Use the IA-PC HPET (High Precision Event Timer) to manage
902	  time in preference to the PIT and RTC, if a HPET is
903	  present.
904	  HPET is the next generation timer replacing legacy 8254s.
905	  The HPET provides a stable time base on SMP
906	  systems, unlike the TSC, but it is more expensive to access,
907	  as it is off-chip.  The interface used is documented
908	  in the HPET spec, revision 1.
909
910	  You can safely choose Y here.  However, HPET will only be
911	  activated if the platform and the BIOS support this feature.
912	  Otherwise the 8254 will be used for timing services.
913
914	  Choose N to continue using the legacy 8254 timer.
915
916config HPET_EMULATE_RTC
917	def_bool y
918	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
919
920# Mark as expert because too many people got it wrong.
921# The code disables itself when not needed.
922config DMI
923	default y
924	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
925	bool "Enable DMI scanning" if EXPERT
926	help
927	  Enabled scanning of DMI to identify machine quirks. Say Y
928	  here unless you have verified that your setup is not
929	  affected by entries in the DMI blacklist. Required by PNP
930	  BIOS code.
931
932config GART_IOMMU
933	bool "Old AMD GART IOMMU support"
934	select DMA_OPS
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   64 if  SMP &&  X86_BIGSMP
993	default    8 if  SMP && !X86_BIGSMP
994	default    1 if !SMP
995
996config NR_CPUS_RANGE_END
997	int
998	depends on X86_64
999	default 8192 if  SMP && CPUMASK_OFFSTACK
1000	default  512 if  SMP && !CPUMASK_OFFSTACK
1001	default    1 if !SMP
1002
1003config NR_CPUS_DEFAULT
1004	int
1005	depends on X86_32
1006	default   32 if  X86_BIGSMP
1007	default    8 if  SMP
1008	default    1 if !SMP
1009
1010config NR_CPUS_DEFAULT
1011	int
1012	depends on X86_64
1013	default 8192 if  MAXSMP
1014	default   64 if  SMP
1015	default    1 if !SMP
1016
1017config NR_CPUS
1018	int "Maximum number of CPUs" if SMP && !MAXSMP
1019	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1020	default NR_CPUS_DEFAULT
1021	help
1022	  This allows you to specify the maximum number of CPUs which this
1023	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1024	  supported value is 8192, otherwise the maximum value is 512.  The
1025	  minimum value which makes sense is 2.
1026
1027	  This is purely to save memory: each supported CPU adds about 8KB
1028	  to the kernel image.
1029
1030config SCHED_CLUSTER
1031	bool "Cluster scheduler support"
1032	depends on SMP
1033	default y
1034	help
1035	  Cluster scheduler support improves the CPU scheduler's decision
1036	  making when dealing with machines that have clusters of CPUs.
1037	  Cluster usually means a couple of CPUs which are placed closely
1038	  by sharing mid-level caches, last-level cache tags or internal
1039	  busses.
1040
1041config SCHED_SMT
1042	def_bool y if SMP
1043
1044config SCHED_MC
1045	def_bool y
1046	prompt "Multi-core scheduler support"
1047	depends on SMP
1048	help
1049	  Multi-core scheduler support improves the CPU scheduler's decision
1050	  making when dealing with multi-core CPU chips at a cost of slightly
1051	  increased overhead in some places. If unsure say N here.
1052
1053config SCHED_MC_PRIO
1054	bool "CPU core priorities scheduler support"
1055	depends on SCHED_MC && CPU_SUP_INTEL
1056	select X86_INTEL_PSTATE
1057	select CPU_FREQ
1058	default y
1059	help
1060	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1061	  core ordering determined at manufacturing time, which allows
1062	  certain cores to reach higher turbo frequencies (when running
1063	  single threaded workloads) than others.
1064
1065	  Enabling this kernel feature teaches the scheduler about
1066	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1067	  scheduler's CPU selection logic accordingly, so that higher
1068	  overall system performance can be achieved.
1069
1070	  This feature will have no effect on CPUs without this feature.
1071
1072	  If unsure say Y here.
1073
1074config UP_LATE_INIT
1075	def_bool y
1076	depends on !SMP && X86_LOCAL_APIC
1077
1078config X86_UP_APIC
1079	bool "Local APIC support on uniprocessors" if !PCI_MSI
1080	default PCI_MSI
1081	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1082	help
1083	  A local APIC (Advanced Programmable Interrupt Controller) is an
1084	  integrated interrupt controller in the CPU. If you have a single-CPU
1085	  system which has a processor with a local APIC, you can say Y here to
1086	  enable and use it. If you say Y here even though your machine doesn't
1087	  have a local APIC, then the kernel will still run with no slowdown at
1088	  all. The local APIC supports CPU-generated self-interrupts (timer,
1089	  performance counters), and the NMI watchdog which detects hard
1090	  lockups.
1091
1092config X86_UP_IOAPIC
1093	bool "IO-APIC support on uniprocessors"
1094	depends on X86_UP_APIC
1095	help
1096	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1097	  SMP-capable replacement for PC-style interrupt controllers. Most
1098	  SMP systems and many recent uniprocessor systems have one.
1099
1100	  If you have a single-CPU system with an IO-APIC, you can say Y here
1101	  to use it. If you say Y here even though your machine doesn't have
1102	  an IO-APIC, then the kernel will still run with no slowdown at all.
1103
1104config X86_LOCAL_APIC
1105	def_bool y
1106	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1107	select IRQ_DOMAIN_HIERARCHY
1108
1109config X86_IO_APIC
1110	def_bool y
1111	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1112
1113config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1114	bool "Reroute for broken boot IRQs"
1115	depends on X86_IO_APIC
1116	help
1117	  This option enables a workaround that fixes a source of
1118	  spurious interrupts. This is recommended when threaded
1119	  interrupt handling is used on systems where the generation of
1120	  superfluous "boot interrupts" cannot be disabled.
1121
1122	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1123	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1124	  kernel does during interrupt handling). On chipsets where this
1125	  boot IRQ generation cannot be disabled, this workaround keeps
1126	  the original IRQ line masked so that only the equivalent "boot
1127	  IRQ" is delivered to the CPUs. The workaround also tells the
1128	  kernel to set up the IRQ handler on the boot IRQ line. In this
1129	  way only one interrupt is delivered to the kernel. Otherwise
1130	  the spurious second interrupt may cause the kernel to bring
1131	  down (vital) interrupt lines.
1132
1133	  Only affects "broken" chipsets. Interrupt sharing may be
1134	  increased on these systems.
1135
1136config X86_MCE
1137	bool "Machine Check / overheating reporting"
1138	select GENERIC_ALLOCATOR
1139	default y
1140	help
1141	  Machine Check support allows the processor to notify the
1142	  kernel if it detects a problem (e.g. overheating, data corruption).
1143	  The action the kernel takes depends on the severity of the problem,
1144	  ranging from warning messages to halting the machine.
1145
1146config X86_MCELOG_LEGACY
1147	bool "Support for deprecated /dev/mcelog character device"
1148	depends on X86_MCE
1149	help
1150	  Enable support for /dev/mcelog which is needed by the old mcelog
1151	  userspace logging daemon. Consider switching to the new generation
1152	  rasdaemon solution.
1153
1154config X86_MCE_INTEL
1155	def_bool y
1156	prompt "Intel MCE features"
1157	depends on X86_MCE && X86_LOCAL_APIC
1158	help
1159	  Additional support for intel specific MCE features such as
1160	  the thermal monitor.
1161
1162config X86_MCE_AMD
1163	def_bool y
1164	prompt "AMD MCE features"
1165	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1166	help
1167	  Additional support for AMD specific MCE features such as
1168	  the DRAM Error Threshold.
1169
1170config X86_ANCIENT_MCE
1171	bool "Support for old Pentium 5 / WinChip machine checks"
1172	depends on X86_32 && X86_MCE
1173	help
1174	  Include support for machine check handling on old Pentium 5 or WinChip
1175	  systems. These typically need to be enabled explicitly on the command
1176	  line.
1177
1178config X86_MCE_THRESHOLD
1179	depends on X86_MCE_AMD || X86_MCE_INTEL
1180	def_bool y
1181
1182config X86_MCE_INJECT
1183	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1184	tristate "Machine check injector support"
1185	help
1186	  Provide support for injecting machine checks for testing purposes.
1187	  If you don't know what a machine check is and you don't do kernel
1188	  QA it is safe to say n.
1189
1190source "arch/x86/events/Kconfig"
1191
1192config X86_LEGACY_VM86
1193	bool "Legacy VM86 support"
1194	depends on X86_32
1195	help
1196	  This option allows user programs to put the CPU into V8086
1197	  mode, which is an 80286-era approximation of 16-bit real mode.
1198
1199	  Some very old versions of X and/or vbetool require this option
1200	  for user mode setting.  Similarly, DOSEMU will use it if
1201	  available to accelerate real mode DOS programs.  However, any
1202	  recent version of DOSEMU, X, or vbetool should be fully
1203	  functional even without kernel VM86 support, as they will all
1204	  fall back to software emulation. Nevertheless, if you are using
1205	  a 16-bit DOS program where 16-bit performance matters, vm86
1206	  mode might be faster than emulation and you might want to
1207	  enable this option.
1208
1209	  Note that any app that works on a 64-bit kernel is unlikely to
1210	  need this option, as 64-bit kernels don't, and can't, support
1211	  V8086 mode. This option is also unrelated to 16-bit protected
1212	  mode and is not needed to run most 16-bit programs under Wine.
1213
1214	  Enabling this option increases the complexity of the kernel
1215	  and slows down exception handling a tiny bit.
1216
1217	  If unsure, say N here.
1218
1219config VM86
1220	bool
1221	default X86_LEGACY_VM86
1222
1223config X86_16BIT
1224	bool "Enable support for 16-bit segments" if EXPERT
1225	default y
1226	depends on MODIFY_LDT_SYSCALL
1227	help
1228	  This option is required by programs like Wine to run 16-bit
1229	  protected mode legacy code on x86 processors.  Disabling
1230	  this option saves about 300 bytes on i386, or around 6K text
1231	  plus 16K runtime memory on x86-64,
1232
1233config X86_ESPFIX32
1234	def_bool y
1235	depends on X86_16BIT && X86_32
1236
1237config X86_ESPFIX64
1238	def_bool y
1239	depends on X86_16BIT && X86_64
1240
1241config X86_VSYSCALL_EMULATION
1242	bool "Enable vsyscall emulation" if EXPERT
1243	default y
1244	depends on X86_64
1245	help
1246	  This enables emulation of the legacy vsyscall page.  Disabling
1247	  it is roughly equivalent to booting with vsyscall=none, except
1248	  that it will also disable the helpful warning if a program
1249	  tries to use a vsyscall.  With this option set to N, offending
1250	  programs will just segfault, citing addresses of the form
1251	  0xffffffffff600?00.
1252
1253	  This option is required by many programs built before 2013, and
1254	  care should be used even with newer programs if set to N.
1255
1256	  Disabling this option saves about 7K of kernel size and
1257	  possibly 4K of additional runtime pagetable memory.
1258
1259config X86_IOPL_IOPERM
1260	bool "IOPERM and IOPL Emulation"
1261	default y
1262	help
1263	  This enables the ioperm() and iopl() syscalls which are necessary
1264	  for legacy applications.
1265
1266	  Legacy IOPL support is an overbroad mechanism which allows user
1267	  space aside of accessing all 65536 I/O ports also to disable
1268	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1269	  capabilities and permission from potentially active security
1270	  modules.
1271
1272	  The emulation restricts the functionality of the syscall to
1273	  only allowing the full range I/O port access, but prevents the
1274	  ability to disable interrupts from user space which would be
1275	  granted if the hardware IOPL mechanism would be used.
1276
1277config TOSHIBA
1278	tristate "Toshiba Laptop support"
1279	depends on X86_32
1280	help
1281	  This adds a driver to safely access the System Management Mode of
1282	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1283	  not work on models with a Phoenix BIOS. The System Management Mode
1284	  is used to set the BIOS and power saving options on Toshiba portables.
1285
1286	  For information on utilities to make use of this driver see the
1287	  Toshiba Linux utilities web site at:
1288	  <http://www.buzzard.org.uk/toshiba/>.
1289
1290	  Say Y if you intend to run this kernel on a Toshiba portable.
1291	  Say N otherwise.
1292
1293config X86_REBOOTFIXUPS
1294	bool "Enable X86 board specific fixups for reboot"
1295	depends on X86_32
1296	help
1297	  This enables chipset and/or board specific fixups to be done
1298	  in order to get reboot to work correctly. This is only needed on
1299	  some combinations of hardware and BIOS. The symptom, for which
1300	  this config is intended, is when reboot ends with a stalled/hung
1301	  system.
1302
1303	  Currently, the only fixup is for the Geode machines using
1304	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1305
1306	  Say Y if you want to enable the fixup. Currently, it's safe to
1307	  enable this option even if you don't need it.
1308	  Say N otherwise.
1309
1310config MICROCODE
1311	def_bool y
1312	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1313
1314config MICROCODE_LATE_LOADING
1315	bool "Late microcode loading (DANGEROUS)"
1316	default n
1317	depends on MICROCODE
1318	help
1319	  Loading microcode late, when the system is up and executing instructions
1320	  is a tricky business and should be avoided if possible. Just the sequence
1321	  of synchronizing all cores and SMT threads is one fragile dance which does
1322	  not guarantee that cores might not softlock after the loading. Therefore,
1323	  use this at your own risk. Late loading taints the kernel too.
1324
1325config X86_MSR
1326	tristate "/dev/cpu/*/msr - Model-specific register support"
1327	help
1328	  This device gives privileged processes access to the x86
1329	  Model-Specific Registers (MSRs).  It is a character device with
1330	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1331	  MSR accesses are directed to a specific CPU on multi-processor
1332	  systems.
1333
1334config X86_CPUID
1335	tristate "/dev/cpu/*/cpuid - CPU information support"
1336	help
1337	  This device gives processes access to the x86 CPUID instruction to
1338	  be executed on a specific processor.  It is a character device
1339	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1340	  /dev/cpu/31/cpuid.
1341
1342choice
1343	prompt "High Memory Support"
1344	default HIGHMEM4G
1345	depends on X86_32
1346
1347config NOHIGHMEM
1348	bool "off"
1349	help
1350	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1351	  However, the address space of 32-bit x86 processors is only 4
1352	  Gigabytes large. That means that, if you have a large amount of
1353	  physical memory, not all of it can be "permanently mapped" by the
1354	  kernel. The physical memory that's not permanently mapped is called
1355	  "high memory".
1356
1357	  If you are compiling a kernel which will never run on a machine with
1358	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1359	  choice and suitable for most users). This will result in a "3GB/1GB"
1360	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1361	  space and the remaining part of the 4GB virtual memory space is used
1362	  by the kernel to permanently map as much physical memory as
1363	  possible.
1364
1365	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1366	  answer "4GB" here.
1367
1368	  If more than 4 Gigabytes is used then answer "64GB" here. This
1369	  selection turns Intel PAE (Physical Address Extension) mode on.
1370	  PAE implements 3-level paging on IA32 processors. PAE is fully
1371	  supported by Linux, PAE mode is implemented on all recent Intel
1372	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1373	  then the kernel will not boot on CPUs that don't support PAE!
1374
1375	  The actual amount of total physical memory will either be
1376	  auto detected or can be forced by using a kernel command line option
1377	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1378	  your boot loader (lilo or loadlin) about how to pass options to the
1379	  kernel at boot time.)
1380
1381	  If unsure, say "off".
1382
1383config HIGHMEM4G
1384	bool "4GB"
1385	help
1386	  Select this if you have a 32-bit processor and between 1 and 4
1387	  gigabytes of physical RAM.
1388
1389config HIGHMEM64G
1390	bool "64GB"
1391	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1392	select X86_PAE
1393	help
1394	  Select this if you have a 32-bit processor and more than 4
1395	  gigabytes of physical RAM.
1396
1397endchoice
1398
1399choice
1400	prompt "Memory split" if EXPERT
1401	default VMSPLIT_3G
1402	depends on X86_32
1403	help
1404	  Select the desired split between kernel and user memory.
1405
1406	  If the address range available to the kernel is less than the
1407	  physical memory installed, the remaining memory will be available
1408	  as "high memory". Accessing high memory is a little more costly
1409	  than low memory, as it needs to be mapped into the kernel first.
1410	  Note that increasing the kernel address space limits the range
1411	  available to user programs, making the address space there
1412	  tighter.  Selecting anything other than the default 3G/1G split
1413	  will also likely make your kernel incompatible with binary-only
1414	  kernel modules.
1415
1416	  If you are not absolutely sure what you are doing, leave this
1417	  option alone!
1418
1419	config VMSPLIT_3G
1420		bool "3G/1G user/kernel split"
1421	config VMSPLIT_3G_OPT
1422		depends on !X86_PAE
1423		bool "3G/1G user/kernel split (for full 1G low memory)"
1424	config VMSPLIT_2G
1425		bool "2G/2G user/kernel split"
1426	config VMSPLIT_2G_OPT
1427		depends on !X86_PAE
1428		bool "2G/2G user/kernel split (for full 2G low memory)"
1429	config VMSPLIT_1G
1430		bool "1G/3G user/kernel split"
1431endchoice
1432
1433config PAGE_OFFSET
1434	hex
1435	default 0xB0000000 if VMSPLIT_3G_OPT
1436	default 0x80000000 if VMSPLIT_2G
1437	default 0x78000000 if VMSPLIT_2G_OPT
1438	default 0x40000000 if VMSPLIT_1G
1439	default 0xC0000000
1440	depends on X86_32
1441
1442config HIGHMEM
1443	def_bool y
1444	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1445
1446config X86_PAE
1447	bool "PAE (Physical Address Extension) Support"
1448	depends on X86_32 && !HIGHMEM4G
1449	select PHYS_ADDR_T_64BIT
1450	select SWIOTLB
1451	help
1452	  PAE is required for NX support, and furthermore enables
1453	  larger swapspace support for non-overcommit purposes. It
1454	  has the cost of more pagetable lookup overhead, and also
1455	  consumes more pagetable space per process.
1456
1457config X86_5LEVEL
1458	bool "Enable 5-level page tables support"
1459	default y
1460	select DYNAMIC_MEMORY_LAYOUT
1461	select SPARSEMEM_VMEMMAP
1462	depends on X86_64
1463	help
1464	  5-level paging enables access to larger address space:
1465	  up to 128 PiB of virtual address space and 4 PiB of
1466	  physical address space.
1467
1468	  It will be supported by future Intel CPUs.
1469
1470	  A kernel with the option enabled can be booted on machines that
1471	  support 4- or 5-level paging.
1472
1473	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1474	  information.
1475
1476	  Say N if unsure.
1477
1478config X86_DIRECT_GBPAGES
1479	def_bool y
1480	depends on X86_64
1481	help
1482	  Certain kernel features effectively disable kernel
1483	  linear 1 GB mappings (even if the CPU otherwise
1484	  supports them), so don't confuse the user by printing
1485	  that we have them enabled.
1486
1487config X86_CPA_STATISTICS
1488	bool "Enable statistic for Change Page Attribute"
1489	depends on DEBUG_FS
1490	help
1491	  Expose statistics about the Change Page Attribute mechanism, which
1492	  helps to determine the effectiveness of preserving large and huge
1493	  page mappings when mapping protections are changed.
1494
1495config X86_MEM_ENCRYPT
1496	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1497	select DYNAMIC_PHYSICAL_MASK
1498	def_bool n
1499
1500config AMD_MEM_ENCRYPT
1501	bool "AMD Secure Memory Encryption (SME) support"
1502	depends on X86_64 && CPU_SUP_AMD
1503	depends on EFI_STUB
1504	select DMA_COHERENT_POOL
1505	select ARCH_USE_MEMREMAP_PROT
1506	select INSTRUCTION_DECODER
1507	select ARCH_HAS_CC_PLATFORM
1508	select X86_MEM_ENCRYPT
1509	select UNACCEPTED_MEMORY
1510	help
1511	  Say yes to enable support for the encryption of system memory.
1512	  This requires an AMD processor that supports Secure Memory
1513	  Encryption (SME).
1514
1515config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1516	bool "Activate AMD Secure Memory Encryption (SME) by default"
1517	depends on AMD_MEM_ENCRYPT
1518	help
1519	  Say yes to have system memory encrypted by default if running on
1520	  an AMD processor that supports Secure Memory Encryption (SME).
1521
1522	  If set to Y, then the encryption of system memory can be
1523	  deactivated with the mem_encrypt=off command line option.
1524
1525	  If set to N, then the encryption of system memory can be
1526	  activated with the mem_encrypt=on command line option.
1527
1528# Common NUMA Features
1529config NUMA
1530	bool "NUMA Memory Allocation and Scheduler Support"
1531	depends on SMP
1532	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1533	default y if X86_BIGSMP
1534	select USE_PERCPU_NUMA_NODE_ID
1535	help
1536	  Enable NUMA (Non-Uniform Memory Access) support.
1537
1538	  The kernel will try to allocate memory used by a CPU on the
1539	  local memory controller of the CPU and add some more
1540	  NUMA awareness to the kernel.
1541
1542	  For 64-bit this is recommended if the system is Intel Core i7
1543	  (or later), AMD Opteron, or EM64T NUMA.
1544
1545	  For 32-bit this is only needed if you boot a 32-bit
1546	  kernel on a 64-bit NUMA platform.
1547
1548	  Otherwise, you should say N.
1549
1550config AMD_NUMA
1551	def_bool y
1552	prompt "Old style AMD Opteron NUMA detection"
1553	depends on X86_64 && NUMA && PCI
1554	help
1555	  Enable AMD NUMA node topology detection.  You should say Y here if
1556	  you have a multi processor AMD system. This uses an old method to
1557	  read the NUMA configuration directly from the builtin Northbridge
1558	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1559	  which also takes priority if both are compiled in.
1560
1561config X86_64_ACPI_NUMA
1562	def_bool y
1563	prompt "ACPI NUMA detection"
1564	depends on X86_64 && NUMA && ACPI && PCI
1565	select ACPI_NUMA
1566	help
1567	  Enable ACPI SRAT based node topology detection.
1568
1569config NUMA_EMU
1570	bool "NUMA emulation"
1571	depends on NUMA
1572	help
1573	  Enable NUMA emulation. A flat machine will be split
1574	  into virtual nodes when booted with "numa=fake=N", where N is the
1575	  number of nodes. This is only useful for debugging.
1576
1577config NODES_SHIFT
1578	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1579	range 1 10
1580	default "10" if MAXSMP
1581	default "6" if X86_64
1582	default "3"
1583	depends on NUMA
1584	help
1585	  Specify the maximum number of NUMA Nodes available on the target
1586	  system.  Increases memory reserved to accommodate various tables.
1587
1588config ARCH_FLATMEM_ENABLE
1589	def_bool y
1590	depends on X86_32 && !NUMA
1591
1592config ARCH_SPARSEMEM_ENABLE
1593	def_bool y
1594	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1595	select SPARSEMEM_STATIC if X86_32
1596	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1597
1598config ARCH_SPARSEMEM_DEFAULT
1599	def_bool X86_64 || (NUMA && X86_32)
1600
1601config ARCH_SELECT_MEMORY_MODEL
1602	def_bool y
1603	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1604
1605config ARCH_MEMORY_PROBE
1606	bool "Enable sysfs memory/probe interface"
1607	depends on MEMORY_HOTPLUG
1608	help
1609	  This option enables a sysfs memory/probe interface for testing.
1610	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1611	  If you are unsure how to answer this question, answer N.
1612
1613config ARCH_PROC_KCORE_TEXT
1614	def_bool y
1615	depends on X86_64 && PROC_KCORE
1616
1617config ILLEGAL_POINTER_VALUE
1618	hex
1619	default 0 if X86_32
1620	default 0xdead000000000000 if X86_64
1621
1622config X86_PMEM_LEGACY_DEVICE
1623	bool
1624
1625config X86_PMEM_LEGACY
1626	tristate "Support non-standard NVDIMMs and ADR protected memory"
1627	depends on PHYS_ADDR_T_64BIT
1628	depends on BLK_DEV
1629	select X86_PMEM_LEGACY_DEVICE
1630	select NUMA_KEEP_MEMINFO if NUMA
1631	select LIBNVDIMM
1632	help
1633	  Treat memory marked using the non-standard e820 type of 12 as used
1634	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1635	  The kernel will offer these regions to the 'pmem' driver so
1636	  they can be used for persistent storage.
1637
1638	  Say Y if unsure.
1639
1640config HIGHPTE
1641	bool "Allocate 3rd-level pagetables from highmem"
1642	depends on HIGHMEM
1643	help
1644	  The VM uses one page table entry for each page of physical memory.
1645	  For systems with a lot of RAM, this can be wasteful of precious
1646	  low memory.  Setting this option will put user-space page table
1647	  entries in high memory.
1648
1649config X86_CHECK_BIOS_CORRUPTION
1650	bool "Check for low memory corruption"
1651	help
1652	  Periodically check for memory corruption in low memory, which
1653	  is suspected to be caused by BIOS.  Even when enabled in the
1654	  configuration, it is disabled at runtime.  Enable it by
1655	  setting "memory_corruption_check=1" on the kernel command
1656	  line.  By default it scans the low 64k of memory every 60
1657	  seconds; see the memory_corruption_check_size and
1658	  memory_corruption_check_period parameters in
1659	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1660
1661	  When enabled with the default parameters, this option has
1662	  almost no overhead, as it reserves a relatively small amount
1663	  of memory and scans it infrequently.  It both detects corruption
1664	  and prevents it from affecting the running system.
1665
1666	  It is, however, intended as a diagnostic tool; if repeatable
1667	  BIOS-originated corruption always affects the same memory,
1668	  you can use memmap= to prevent the kernel from using that
1669	  memory.
1670
1671config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1672	bool "Set the default setting of memory_corruption_check"
1673	depends on X86_CHECK_BIOS_CORRUPTION
1674	default y
1675	help
1676	  Set whether the default state of memory_corruption_check is
1677	  on or off.
1678
1679config MATH_EMULATION
1680	bool
1681	depends on MODIFY_LDT_SYSCALL
1682	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1683	help
1684	  Linux can emulate a math coprocessor (used for floating point
1685	  operations) if you don't have one. 486DX and Pentium processors have
1686	  a math coprocessor built in, 486SX and 386 do not, unless you added
1687	  a 487DX or 387, respectively. (The messages during boot time can
1688	  give you some hints here ["man dmesg"].) Everyone needs either a
1689	  coprocessor or this emulation.
1690
1691	  If you don't have a math coprocessor, you need to say Y here; if you
1692	  say Y here even though you have a coprocessor, the coprocessor will
1693	  be used nevertheless. (This behavior can be changed with the kernel
1694	  command line option "no387", which comes handy if your coprocessor
1695	  is broken. Try "man bootparam" or see the documentation of your boot
1696	  loader (lilo or loadlin) about how to pass options to the kernel at
1697	  boot time.) This means that it is a good idea to say Y here if you
1698	  intend to use this kernel on different machines.
1699
1700	  More information about the internals of the Linux math coprocessor
1701	  emulation can be found in <file:arch/x86/math-emu/README>.
1702
1703	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1704	  kernel, it won't hurt.
1705
1706config MTRR
1707	def_bool y
1708	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1709	help
1710	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1711	  the Memory Type Range Registers (MTRRs) may be used to control
1712	  processor access to memory ranges. This is most useful if you have
1713	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1714	  allows bus write transfers to be combined into a larger transfer
1715	  before bursting over the PCI/AGP bus. This can increase performance
1716	  of image write operations 2.5 times or more. Saying Y here creates a
1717	  /proc/mtrr file which may be used to manipulate your processor's
1718	  MTRRs. Typically the X server should use this.
1719
1720	  This code has a reasonably generic interface so that similar
1721	  control registers on other processors can be easily supported
1722	  as well:
1723
1724	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1725	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1726	  these, the ARRs are used to emulate the MTRRs.
1727	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1728	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1729	  write-combining. All of these processors are supported by this code
1730	  and it makes sense to say Y here if you have one of them.
1731
1732	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1733	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1734	  can lead to all sorts of problems, so it's good to say Y here.
1735
1736	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1737	  just add about 9 KB to your kernel.
1738
1739	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1740
1741config MTRR_SANITIZER
1742	def_bool y
1743	prompt "MTRR cleanup support"
1744	depends on MTRR
1745	help
1746	  Convert MTRR layout from continuous to discrete, so X drivers can
1747	  add writeback entries.
1748
1749	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1750	  The largest mtrr entry size for a continuous block can be set with
1751	  mtrr_chunk_size.
1752
1753	  If unsure, say Y.
1754
1755config MTRR_SANITIZER_ENABLE_DEFAULT
1756	int "MTRR cleanup enable value (0-1)"
1757	range 0 1
1758	default "0"
1759	depends on MTRR_SANITIZER
1760	help
1761	  Enable mtrr cleanup default value
1762
1763config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1764	int "MTRR cleanup spare reg num (0-7)"
1765	range 0 7
1766	default "1"
1767	depends on MTRR_SANITIZER
1768	help
1769	  mtrr cleanup spare entries default, it can be changed via
1770	  mtrr_spare_reg_nr=N on the kernel command line.
1771
1772config X86_PAT
1773	def_bool y
1774	prompt "x86 PAT support" if EXPERT
1775	depends on MTRR
1776	help
1777	  Use PAT attributes to setup page level cache control.
1778
1779	  PATs are the modern equivalents of MTRRs and are much more
1780	  flexible than MTRRs.
1781
1782	  Say N here if you see bootup problems (boot crash, boot hang,
1783	  spontaneous reboots) or a non-working video driver.
1784
1785	  If unsure, say Y.
1786
1787config ARCH_USES_PG_UNCACHED
1788	def_bool y
1789	depends on X86_PAT
1790
1791config X86_UMIP
1792	def_bool y
1793	prompt "User Mode Instruction Prevention" if EXPERT
1794	help
1795	  User Mode Instruction Prevention (UMIP) is a security feature in
1796	  some x86 processors. If enabled, a general protection fault is
1797	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1798	  executed in user mode. These instructions unnecessarily expose
1799	  information about the hardware state.
1800
1801	  The vast majority of applications do not use these instructions.
1802	  For the very few that do, software emulation is provided in
1803	  specific cases in protected and virtual-8086 modes. Emulated
1804	  results are dummy.
1805
1806config CC_HAS_IBT
1807	# GCC >= 9 and binutils >= 2.29
1808	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1809	# Clang/LLVM >= 14
1810	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1811	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1812	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1813		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1814		  $(as-instr,endbr64)
1815
1816config X86_KERNEL_IBT
1817	prompt "Indirect Branch Tracking"
1818	def_bool y
1819	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1820	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1821	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1822	select OBJTOOL
1823	help
1824	  Build the kernel with support for Indirect Branch Tracking, a
1825	  hardware support course-grain forward-edge Control Flow Integrity
1826	  protection. It enforces that all indirect calls must land on
1827	  an ENDBR instruction, as such, the compiler will instrument the
1828	  code with them to make this happen.
1829
1830	  In addition to building the kernel with IBT, seal all functions that
1831	  are not indirect call targets, avoiding them ever becoming one.
1832
1833	  This requires LTO like objtool runs and will slow down the build. It
1834	  does significantly reduce the number of ENDBR instructions in the
1835	  kernel image.
1836
1837config X86_INTEL_MEMORY_PROTECTION_KEYS
1838	prompt "Memory Protection Keys"
1839	def_bool y
1840	# Note: only available in 64-bit mode
1841	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1842	select ARCH_USES_HIGH_VMA_FLAGS
1843	select ARCH_HAS_PKEYS
1844	help
1845	  Memory Protection Keys provides a mechanism for enforcing
1846	  page-based protections, but without requiring modification of the
1847	  page tables when an application changes protection domains.
1848
1849	  For details, see Documentation/core-api/protection-keys.rst
1850
1851	  If unsure, say y.
1852
1853choice
1854	prompt "TSX enable mode"
1855	depends on CPU_SUP_INTEL
1856	default X86_INTEL_TSX_MODE_OFF
1857	help
1858	  Intel's TSX (Transactional Synchronization Extensions) feature
1859	  allows to optimize locking protocols through lock elision which
1860	  can lead to a noticeable performance boost.
1861
1862	  On the other hand it has been shown that TSX can be exploited
1863	  to form side channel attacks (e.g. TAA) and chances are there
1864	  will be more of those attacks discovered in the future.
1865
1866	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1867	  might override this decision by tsx=on the command line parameter.
1868	  Even with TSX enabled, the kernel will attempt to enable the best
1869	  possible TAA mitigation setting depending on the microcode available
1870	  for the particular machine.
1871
1872	  This option allows to set the default tsx mode between tsx=on, =off
1873	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1874	  details.
1875
1876	  Say off if not sure, auto if TSX is in use but it should be used on safe
1877	  platforms or on if TSX is in use and the security aspect of tsx is not
1878	  relevant.
1879
1880config X86_INTEL_TSX_MODE_OFF
1881	bool "off"
1882	help
1883	  TSX is disabled if possible - equals to tsx=off command line parameter.
1884
1885config X86_INTEL_TSX_MODE_ON
1886	bool "on"
1887	help
1888	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1889	  line parameter.
1890
1891config X86_INTEL_TSX_MODE_AUTO
1892	bool "auto"
1893	help
1894	  TSX is enabled on TSX capable HW that is believed to be safe against
1895	  side channel attacks- equals the tsx=auto command line parameter.
1896endchoice
1897
1898config X86_SGX
1899	bool "Software Guard eXtensions (SGX)"
1900	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1901	depends on CRYPTO=y
1902	depends on CRYPTO_SHA256=y
1903	select MMU_NOTIFIER
1904	select NUMA_KEEP_MEMINFO if NUMA
1905	select XARRAY_MULTI
1906	help
1907	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1908	  that can be used by applications to set aside private regions of code
1909	  and data, referred to as enclaves. An enclave's private memory can
1910	  only be accessed by code running within the enclave. Accesses from
1911	  outside the enclave, including other enclaves, are disallowed by
1912	  hardware.
1913
1914	  If unsure, say N.
1915
1916config EFI
1917	bool "EFI runtime service support"
1918	depends on ACPI
1919	select UCS2_STRING
1920	select EFI_RUNTIME_WRAPPERS
1921	select ARCH_USE_MEMREMAP_PROT
1922	help
1923	  This enables the kernel to use EFI runtime services that are
1924	  available (such as the EFI variable services).
1925
1926	  This option is only useful on systems that have EFI firmware.
1927	  In addition, you should use the latest ELILO loader available
1928	  at <http://elilo.sourceforge.net> in order to take advantage
1929	  of EFI runtime services. However, even with this option, the
1930	  resultant kernel should continue to boot on existing non-EFI
1931	  platforms.
1932
1933config EFI_STUB
1934	bool "EFI stub support"
1935	depends on EFI
1936	select RELOCATABLE
1937	help
1938	  This kernel feature allows a bzImage to be loaded directly
1939	  by EFI firmware without the use of a bootloader.
1940
1941	  See Documentation/admin-guide/efi-stub.rst for more information.
1942
1943config EFI_HANDOVER_PROTOCOL
1944	bool "EFI handover protocol (DEPRECATED)"
1945	depends on EFI_STUB
1946	default y
1947	help
1948	  Select this in order to include support for the deprecated EFI
1949	  handover protocol, which defines alternative entry points into the
1950	  EFI stub.  This is a practice that has no basis in the UEFI
1951	  specification, and requires a priori knowledge on the part of the
1952	  bootloader about Linux/x86 specific ways of passing the command line
1953	  and initrd, and where in memory those assets may be loaded.
1954
1955	  If in doubt, say Y. Even though the corresponding support is not
1956	  present in upstream GRUB or other bootloaders, most distros build
1957	  GRUB with numerous downstream patches applied, and may rely on the
1958	  handover protocol as as result.
1959
1960config EFI_MIXED
1961	bool "EFI mixed-mode support"
1962	depends on EFI_STUB && X86_64
1963	help
1964	  Enabling this feature allows a 64-bit kernel to be booted
1965	  on a 32-bit firmware, provided that your CPU supports 64-bit
1966	  mode.
1967
1968	  Note that it is not possible to boot a mixed-mode enabled
1969	  kernel via the EFI boot stub - a bootloader that supports
1970	  the EFI handover protocol must be used.
1971
1972	  If unsure, say N.
1973
1974config EFI_FAKE_MEMMAP
1975	bool "Enable EFI fake memory map"
1976	depends on EFI
1977	help
1978	  Saying Y here will enable "efi_fake_mem" boot option.  By specifying
1979	  this parameter, you can add arbitrary attribute to specific memory
1980	  range by updating original (firmware provided) EFI memmap.  This is
1981	  useful for debugging of EFI memmap related feature, e.g., Address
1982	  Range Mirroring feature.
1983
1984config EFI_MAX_FAKE_MEM
1985	int "maximum allowable number of ranges in efi_fake_mem boot option"
1986	depends on EFI_FAKE_MEMMAP
1987	range 1 128
1988	default 8
1989	help
1990	  Maximum allowable number of ranges in efi_fake_mem boot option.
1991	  Ranges can be set up to this value using comma-separated list.
1992	  The default value is 8.
1993
1994config EFI_RUNTIME_MAP
1995	bool "Export EFI runtime maps to sysfs" if EXPERT
1996	depends on EFI
1997	default KEXEC_CORE
1998	help
1999	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2000	  That memory map is required by the 2nd kernel to set up EFI virtual
2001	  mappings after kexec, but can also be used for debugging purposes.
2002
2003	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2004
2005source "kernel/Kconfig.hz"
2006
2007config KEXEC
2008	bool "kexec system call"
2009	select KEXEC_CORE
2010	help
2011	  kexec is a system call that implements the ability to shutdown your
2012	  current kernel, and to start another kernel.  It is like a reboot
2013	  but it is independent of the system firmware.   And like a reboot
2014	  you can start any kernel with it, not just Linux.
2015
2016	  The name comes from the similarity to the exec system call.
2017
2018	  It is an ongoing process to be certain the hardware in a machine
2019	  is properly shutdown, so do not be surprised if this code does not
2020	  initially work for you.  As of this writing the exact hardware
2021	  interface is strongly in flux, so no good recommendation can be
2022	  made.
2023
2024config KEXEC_FILE
2025	bool "kexec file based system call"
2026	select KEXEC_CORE
2027	select HAVE_IMA_KEXEC if IMA
2028	depends on X86_64
2029	depends on CRYPTO=y
2030	depends on CRYPTO_SHA256=y
2031	help
2032	  This is new version of kexec system call. This system call is
2033	  file based and takes file descriptors as system call argument
2034	  for kernel and initramfs as opposed to list of segments as
2035	  accepted by previous system call.
2036
2037config ARCH_HAS_KEXEC_PURGATORY
2038	def_bool KEXEC_FILE
2039
2040config KEXEC_SIG
2041	bool "Verify kernel signature during kexec_file_load() syscall"
2042	depends on KEXEC_FILE
2043	help
2044
2045	  This option makes the kexec_file_load() syscall check for a valid
2046	  signature of the kernel image.  The image can still be loaded without
2047	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2048	  there's a signature that we can check, then it must be valid.
2049
2050	  In addition to this option, you need to enable signature
2051	  verification for the corresponding kernel image type being
2052	  loaded in order for this to work.
2053
2054config KEXEC_SIG_FORCE
2055	bool "Require a valid signature in kexec_file_load() syscall"
2056	depends on KEXEC_SIG
2057	help
2058	  This option makes kernel signature verification mandatory for
2059	  the kexec_file_load() syscall.
2060
2061config KEXEC_BZIMAGE_VERIFY_SIG
2062	bool "Enable bzImage signature verification support"
2063	depends on KEXEC_SIG
2064	depends on SIGNED_PE_FILE_VERIFICATION
2065	select SYSTEM_TRUSTED_KEYRING
2066	help
2067	  Enable bzImage signature verification support.
2068
2069config CRASH_DUMP
2070	bool "kernel crash dumps"
2071	depends on X86_64 || (X86_32 && HIGHMEM)
2072	help
2073	  Generate crash dump after being started by kexec.
2074	  This should be normally only set in special crash dump kernels
2075	  which are loaded in the main kernel with kexec-tools into
2076	  a specially reserved region and then later executed after
2077	  a crash by kdump/kexec. The crash dump kernel must be compiled
2078	  to a memory address not used by the main kernel or BIOS using
2079	  PHYSICAL_START, or it must be built as a relocatable image
2080	  (CONFIG_RELOCATABLE=y).
2081	  For more details see Documentation/admin-guide/kdump/kdump.rst
2082
2083config KEXEC_JUMP
2084	bool "kexec jump"
2085	depends on KEXEC && HIBERNATION
2086	help
2087	  Jump between original kernel and kexeced kernel and invoke
2088	  code in physical address mode via KEXEC
2089
2090config PHYSICAL_START
2091	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2092	default "0x1000000"
2093	help
2094	  This gives the physical address where the kernel is loaded.
2095
2096	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2097	  bzImage will decompress itself to above physical address and
2098	  run from there. Otherwise, bzImage will run from the address where
2099	  it has been loaded by the boot loader and will ignore above physical
2100	  address.
2101
2102	  In normal kdump cases one does not have to set/change this option
2103	  as now bzImage can be compiled as a completely relocatable image
2104	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2105	  address. This option is mainly useful for the folks who don't want
2106	  to use a bzImage for capturing the crash dump and want to use a
2107	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2108	  to be specifically compiled to run from a specific memory area
2109	  (normally a reserved region) and this option comes handy.
2110
2111	  So if you are using bzImage for capturing the crash dump,
2112	  leave the value here unchanged to 0x1000000 and set
2113	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2114	  for capturing the crash dump change this value to start of
2115	  the reserved region.  In other words, it can be set based on
2116	  the "X" value as specified in the "crashkernel=YM@XM"
2117	  command line boot parameter passed to the panic-ed
2118	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2119	  for more details about crash dumps.
2120
2121	  Usage of bzImage for capturing the crash dump is recommended as
2122	  one does not have to build two kernels. Same kernel can be used
2123	  as production kernel and capture kernel. Above option should have
2124	  gone away after relocatable bzImage support is introduced. But it
2125	  is present because there are users out there who continue to use
2126	  vmlinux for dump capture. This option should go away down the
2127	  line.
2128
2129	  Don't change this unless you know what you are doing.
2130
2131config RELOCATABLE
2132	bool "Build a relocatable kernel"
2133	default y
2134	help
2135	  This builds a kernel image that retains relocation information
2136	  so it can be loaded someplace besides the default 1MB.
2137	  The relocations tend to make the kernel binary about 10% larger,
2138	  but are discarded at runtime.
2139
2140	  One use is for the kexec on panic case where the recovery kernel
2141	  must live at a different physical address than the primary
2142	  kernel.
2143
2144	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2145	  it has been loaded at and the compile time physical address
2146	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2147
2148config RANDOMIZE_BASE
2149	bool "Randomize the address of the kernel image (KASLR)"
2150	depends on RELOCATABLE
2151	default y
2152	help
2153	  In support of Kernel Address Space Layout Randomization (KASLR),
2154	  this randomizes the physical address at which the kernel image
2155	  is decompressed and the virtual address where the kernel
2156	  image is mapped, as a security feature that deters exploit
2157	  attempts relying on knowledge of the location of kernel
2158	  code internals.
2159
2160	  On 64-bit, the kernel physical and virtual addresses are
2161	  randomized separately. The physical address will be anywhere
2162	  between 16MB and the top of physical memory (up to 64TB). The
2163	  virtual address will be randomized from 16MB up to 1GB (9 bits
2164	  of entropy). Note that this also reduces the memory space
2165	  available to kernel modules from 1.5GB to 1GB.
2166
2167	  On 32-bit, the kernel physical and virtual addresses are
2168	  randomized together. They will be randomized from 16MB up to
2169	  512MB (8 bits of entropy).
2170
2171	  Entropy is generated using the RDRAND instruction if it is
2172	  supported. If RDTSC is supported, its value is mixed into
2173	  the entropy pool as well. If neither RDRAND nor RDTSC are
2174	  supported, then entropy is read from the i8254 timer. The
2175	  usable entropy is limited by the kernel being built using
2176	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2177	  minimum of 2MB. As a result, only 10 bits of entropy are
2178	  theoretically possible, but the implementations are further
2179	  limited due to memory layouts.
2180
2181	  If unsure, say Y.
2182
2183# Relocation on x86 needs some additional build support
2184config X86_NEED_RELOCS
2185	def_bool y
2186	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2187
2188config PHYSICAL_ALIGN
2189	hex "Alignment value to which kernel should be aligned"
2190	default "0x200000"
2191	range 0x2000 0x1000000 if X86_32
2192	range 0x200000 0x1000000 if X86_64
2193	help
2194	  This value puts the alignment restrictions on physical address
2195	  where kernel is loaded and run from. Kernel is compiled for an
2196	  address which meets above alignment restriction.
2197
2198	  If bootloader loads the kernel at a non-aligned address and
2199	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2200	  address aligned to above value and run from there.
2201
2202	  If bootloader loads the kernel at a non-aligned address and
2203	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2204	  load address and decompress itself to the address it has been
2205	  compiled for and run from there. The address for which kernel is
2206	  compiled already meets above alignment restrictions. Hence the
2207	  end result is that kernel runs from a physical address meeting
2208	  above alignment restrictions.
2209
2210	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2211	  this value must be a multiple of 0x200000.
2212
2213	  Don't change this unless you know what you are doing.
2214
2215config DYNAMIC_MEMORY_LAYOUT
2216	bool
2217	help
2218	  This option makes base addresses of vmalloc and vmemmap as well as
2219	  __PAGE_OFFSET movable during boot.
2220
2221config RANDOMIZE_MEMORY
2222	bool "Randomize the kernel memory sections"
2223	depends on X86_64
2224	depends on RANDOMIZE_BASE
2225	select DYNAMIC_MEMORY_LAYOUT
2226	default RANDOMIZE_BASE
2227	help
2228	  Randomizes the base virtual address of kernel memory sections
2229	  (physical memory mapping, vmalloc & vmemmap). This security feature
2230	  makes exploits relying on predictable memory locations less reliable.
2231
2232	  The order of allocations remains unchanged. Entropy is generated in
2233	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2234	  configuration have in average 30,000 different possible virtual
2235	  addresses for each memory section.
2236
2237	  If unsure, say Y.
2238
2239config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2240	hex "Physical memory mapping padding" if EXPERT
2241	depends on RANDOMIZE_MEMORY
2242	default "0xa" if MEMORY_HOTPLUG
2243	default "0x0"
2244	range 0x1 0x40 if MEMORY_HOTPLUG
2245	range 0x0 0x40
2246	help
2247	  Define the padding in terabytes added to the existing physical
2248	  memory size during kernel memory randomization. It is useful
2249	  for memory hotplug support but reduces the entropy available for
2250	  address randomization.
2251
2252	  If unsure, leave at the default value.
2253
2254config ADDRESS_MASKING
2255	bool "Linear Address Masking support"
2256	depends on X86_64
2257	help
2258	  Linear Address Masking (LAM) modifies the checking that is applied
2259	  to 64-bit linear addresses, allowing software to use of the
2260	  untranslated address bits for metadata.
2261
2262	  The capability can be used for efficient address sanitizers (ASAN)
2263	  implementation and for optimizations in JITs.
2264
2265config HOTPLUG_CPU
2266	def_bool y
2267	depends on SMP
2268
2269config COMPAT_VDSO
2270	def_bool n
2271	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2272	depends on COMPAT_32
2273	help
2274	  Certain buggy versions of glibc will crash if they are
2275	  presented with a 32-bit vDSO that is not mapped at the address
2276	  indicated in its segment table.
2277
2278	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2279	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2280	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2281	  the only released version with the bug, but OpenSUSE 9
2282	  contains a buggy "glibc 2.3.2".
2283
2284	  The symptom of the bug is that everything crashes on startup, saying:
2285	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2286
2287	  Saying Y here changes the default value of the vdso32 boot
2288	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2289	  This works around the glibc bug but hurts performance.
2290
2291	  If unsure, say N: if you are compiling your own kernel, you
2292	  are unlikely to be using a buggy version of glibc.
2293
2294choice
2295	prompt "vsyscall table for legacy applications"
2296	depends on X86_64
2297	default LEGACY_VSYSCALL_XONLY
2298	help
2299	  Legacy user code that does not know how to find the vDSO expects
2300	  to be able to issue three syscalls by calling fixed addresses in
2301	  kernel space. Since this location is not randomized with ASLR,
2302	  it can be used to assist security vulnerability exploitation.
2303
2304	  This setting can be changed at boot time via the kernel command
2305	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2306	  is deprecated and can only be enabled using the kernel command
2307	  line.
2308
2309	  On a system with recent enough glibc (2.14 or newer) and no
2310	  static binaries, you can say None without a performance penalty
2311	  to improve security.
2312
2313	  If unsure, select "Emulate execution only".
2314
2315	config LEGACY_VSYSCALL_XONLY
2316		bool "Emulate execution only"
2317		help
2318		  The kernel traps and emulates calls into the fixed vsyscall
2319		  address mapping and does not allow reads.  This
2320		  configuration is recommended when userspace might use the
2321		  legacy vsyscall area but support for legacy binary
2322		  instrumentation of legacy code is not needed.  It mitigates
2323		  certain uses of the vsyscall area as an ASLR-bypassing
2324		  buffer.
2325
2326	config LEGACY_VSYSCALL_NONE
2327		bool "None"
2328		help
2329		  There will be no vsyscall mapping at all. This will
2330		  eliminate any risk of ASLR bypass due to the vsyscall
2331		  fixed address mapping. Attempts to use the vsyscalls
2332		  will be reported to dmesg, so that either old or
2333		  malicious userspace programs can be identified.
2334
2335endchoice
2336
2337config CMDLINE_BOOL
2338	bool "Built-in kernel command line"
2339	help
2340	  Allow for specifying boot arguments to the kernel at
2341	  build time.  On some systems (e.g. embedded ones), it is
2342	  necessary or convenient to provide some or all of the
2343	  kernel boot arguments with the kernel itself (that is,
2344	  to not rely on the boot loader to provide them.)
2345
2346	  To compile command line arguments into the kernel,
2347	  set this option to 'Y', then fill in the
2348	  boot arguments in CONFIG_CMDLINE.
2349
2350	  Systems with fully functional boot loaders (i.e. non-embedded)
2351	  should leave this option set to 'N'.
2352
2353config CMDLINE
2354	string "Built-in kernel command string"
2355	depends on CMDLINE_BOOL
2356	default ""
2357	help
2358	  Enter arguments here that should be compiled into the kernel
2359	  image and used at boot time.  If the boot loader provides a
2360	  command line at boot time, it is appended to this string to
2361	  form the full kernel command line, when the system boots.
2362
2363	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2364	  change this behavior.
2365
2366	  In most cases, the command line (whether built-in or provided
2367	  by the boot loader) should specify the device for the root
2368	  file system.
2369
2370config CMDLINE_OVERRIDE
2371	bool "Built-in command line overrides boot loader arguments"
2372	depends on CMDLINE_BOOL && CMDLINE != ""
2373	help
2374	  Set this option to 'Y' to have the kernel ignore the boot loader
2375	  command line, and use ONLY the built-in command line.
2376
2377	  This is used to work around broken boot loaders.  This should
2378	  be set to 'N' under normal conditions.
2379
2380config MODIFY_LDT_SYSCALL
2381	bool "Enable the LDT (local descriptor table)" if EXPERT
2382	default y
2383	help
2384	  Linux can allow user programs to install a per-process x86
2385	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2386	  call.  This is required to run 16-bit or segmented code such as
2387	  DOSEMU or some Wine programs.  It is also used by some very old
2388	  threading libraries.
2389
2390	  Enabling this feature adds a small amount of overhead to
2391	  context switches and increases the low-level kernel attack
2392	  surface.  Disabling it removes the modify_ldt(2) system call.
2393
2394	  Saying 'N' here may make sense for embedded or server kernels.
2395
2396config STRICT_SIGALTSTACK_SIZE
2397	bool "Enforce strict size checking for sigaltstack"
2398	depends on DYNAMIC_SIGFRAME
2399	help
2400	  For historical reasons MINSIGSTKSZ is a constant which became
2401	  already too small with AVX512 support. Add a mechanism to
2402	  enforce strict checking of the sigaltstack size against the
2403	  real size of the FPU frame. This option enables the check
2404	  by default. It can also be controlled via the kernel command
2405	  line option 'strict_sas_size' independent of this config
2406	  switch. Enabling it might break existing applications which
2407	  allocate a too small sigaltstack but 'work' because they
2408	  never get a signal delivered.
2409
2410	  Say 'N' unless you want to really enforce this check.
2411
2412source "kernel/livepatch/Kconfig"
2413
2414endmenu
2415
2416config CC_HAS_SLS
2417	def_bool $(cc-option,-mharden-sls=all)
2418
2419config CC_HAS_RETURN_THUNK
2420	def_bool $(cc-option,-mfunction-return=thunk-extern)
2421
2422config CC_HAS_ENTRY_PADDING
2423	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2424
2425config FUNCTION_PADDING_CFI
2426	int
2427	default 59 if FUNCTION_ALIGNMENT_64B
2428	default 27 if FUNCTION_ALIGNMENT_32B
2429	default 11 if FUNCTION_ALIGNMENT_16B
2430	default  3 if FUNCTION_ALIGNMENT_8B
2431	default  0
2432
2433# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2434# except Kconfig can't do arithmetic :/
2435config FUNCTION_PADDING_BYTES
2436	int
2437	default FUNCTION_PADDING_CFI if CFI_CLANG
2438	default FUNCTION_ALIGNMENT
2439
2440config CALL_PADDING
2441	def_bool n
2442	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2443	select FUNCTION_ALIGNMENT_16B
2444
2445config FINEIBT
2446	def_bool y
2447	depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE
2448	select CALL_PADDING
2449
2450config HAVE_CALL_THUNKS
2451	def_bool y
2452	depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL
2453
2454config CALL_THUNKS
2455	def_bool n
2456	select CALL_PADDING
2457
2458config PREFIX_SYMBOLS
2459	def_bool y
2460	depends on CALL_PADDING && !CFI_CLANG
2461
2462menuconfig SPECULATION_MITIGATIONS
2463	bool "Mitigations for speculative execution vulnerabilities"
2464	default y
2465	help
2466	  Say Y here to enable options which enable mitigations for
2467	  speculative execution hardware vulnerabilities.
2468
2469	  If you say N, all mitigations will be disabled. You really
2470	  should know what you are doing to say so.
2471
2472if SPECULATION_MITIGATIONS
2473
2474config PAGE_TABLE_ISOLATION
2475	bool "Remove the kernel mapping in user mode"
2476	default y
2477	depends on (X86_64 || X86_PAE)
2478	help
2479	  This feature reduces the number of hardware side channels by
2480	  ensuring that the majority of kernel addresses are not mapped
2481	  into userspace.
2482
2483	  See Documentation/arch/x86/pti.rst for more details.
2484
2485config RETPOLINE
2486	bool "Avoid speculative indirect branches in kernel"
2487	select OBJTOOL if HAVE_OBJTOOL
2488	default y
2489	help
2490	  Compile kernel with the retpoline compiler options to guard against
2491	  kernel-to-user data leaks by avoiding speculative indirect
2492	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2493	  support for full protection. The kernel may run slower.
2494
2495config RETHUNK
2496	bool "Enable return-thunks"
2497	depends on RETPOLINE && CC_HAS_RETURN_THUNK
2498	select OBJTOOL if HAVE_OBJTOOL
2499	default y if X86_64
2500	help
2501	  Compile the kernel with the return-thunks compiler option to guard
2502	  against kernel-to-user data leaks by avoiding return speculation.
2503	  Requires a compiler with -mfunction-return=thunk-extern
2504	  support for full protection. The kernel may run slower.
2505
2506config CPU_UNRET_ENTRY
2507	bool "Enable UNRET on kernel entry"
2508	depends on CPU_SUP_AMD && RETHUNK && X86_64
2509	default y
2510	help
2511	  Compile the kernel with support for the retbleed=unret mitigation.
2512
2513config CALL_DEPTH_TRACKING
2514	bool "Mitigate RSB underflow with call depth tracking"
2515	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2516	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2517	select CALL_THUNKS
2518	default y
2519	help
2520	  Compile the kernel with call depth tracking to mitigate the Intel
2521	  SKL Return-Speculation-Buffer (RSB) underflow issue. The
2522	  mitigation is off by default and needs to be enabled on the
2523	  kernel command line via the retbleed=stuff option. For
2524	  non-affected systems the overhead of this option is marginal as
2525	  the call depth tracking is using run-time generated call thunks
2526	  in a compiler generated padding area and call patching. This
2527	  increases text size by ~5%. For non affected systems this space
2528	  is unused. On affected SKL systems this results in a significant
2529	  performance gain over the IBRS mitigation.
2530
2531config CALL_THUNKS_DEBUG
2532	bool "Enable call thunks and call depth tracking debugging"
2533	depends on CALL_DEPTH_TRACKING
2534	select FUNCTION_ALIGNMENT_32B
2535	default n
2536	help
2537	  Enable call/ret counters for imbalance detection and build in
2538	  a noisy dmesg about callthunks generation and call patching for
2539	  trouble shooting. The debug prints need to be enabled on the
2540	  kernel command line with 'debug-callthunks'.
2541	  Only enable this when you are debugging call thunks as this
2542	  creates a noticeable runtime overhead. If unsure say N.
2543
2544config CPU_IBPB_ENTRY
2545	bool "Enable IBPB on kernel entry"
2546	depends on CPU_SUP_AMD && X86_64
2547	default y
2548	help
2549	  Compile the kernel with support for the retbleed=ibpb mitigation.
2550
2551config CPU_IBRS_ENTRY
2552	bool "Enable IBRS on kernel entry"
2553	depends on CPU_SUP_INTEL && X86_64
2554	default y
2555	help
2556	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2557	  This mitigates both spectre_v2 and retbleed at great cost to
2558	  performance.
2559
2560config CPU_SRSO
2561	bool "Mitigate speculative RAS overflow on AMD"
2562	depends on CPU_SUP_AMD && X86_64 && RETHUNK
2563	default y
2564	help
2565	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2566
2567config SLS
2568	bool "Mitigate Straight-Line-Speculation"
2569	depends on CC_HAS_SLS && X86_64
2570	select OBJTOOL if HAVE_OBJTOOL
2571	default n
2572	help
2573	  Compile the kernel with straight-line-speculation options to guard
2574	  against straight line speculation. The kernel image might be slightly
2575	  larger.
2576
2577config GDS_FORCE_MITIGATION
2578	bool "Force GDS Mitigation"
2579	depends on CPU_SUP_INTEL
2580	default n
2581	help
2582	  Gather Data Sampling (GDS) is a hardware vulnerability which allows
2583	  unprivileged speculative access to data which was previously stored in
2584	  vector registers.
2585
2586	  This option is equivalent to setting gather_data_sampling=force on the
2587	  command line. The microcode mitigation is used if present, otherwise
2588	  AVX is disabled as a mitigation. On affected systems that are missing
2589	  the microcode any userspace code that unconditionally uses AVX will
2590	  break with this option set.
2591
2592	  Setting this option on systems not vulnerable to GDS has no effect.
2593
2594	  If in doubt, say N.
2595
2596endif
2597
2598config ARCH_HAS_ADD_PAGES
2599	def_bool y
2600	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2601
2602config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2603	def_bool y
2604
2605menu "Power management and ACPI options"
2606
2607config ARCH_HIBERNATION_HEADER
2608	def_bool y
2609	depends on HIBERNATION
2610
2611source "kernel/power/Kconfig"
2612
2613source "drivers/acpi/Kconfig"
2614
2615config X86_APM_BOOT
2616	def_bool y
2617	depends on APM
2618
2619menuconfig APM
2620	tristate "APM (Advanced Power Management) BIOS support"
2621	depends on X86_32 && PM_SLEEP
2622	help
2623	  APM is a BIOS specification for saving power using several different
2624	  techniques. This is mostly useful for battery powered laptops with
2625	  APM compliant BIOSes. If you say Y here, the system time will be
2626	  reset after a RESUME operation, the /proc/apm device will provide
2627	  battery status information, and user-space programs will receive
2628	  notification of APM "events" (e.g. battery status change).
2629
2630	  If you select "Y" here, you can disable actual use of the APM
2631	  BIOS by passing the "apm=off" option to the kernel at boot time.
2632
2633	  Note that the APM support is almost completely disabled for
2634	  machines with more than one CPU.
2635
2636	  In order to use APM, you will need supporting software. For location
2637	  and more information, read <file:Documentation/power/apm-acpi.rst>
2638	  and the Battery Powered Linux mini-HOWTO, available from
2639	  <http://www.tldp.org/docs.html#howto>.
2640
2641	  This driver does not spin down disk drives (see the hdparm(8)
2642	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2643	  VESA-compliant "green" monitors.
2644
2645	  This driver does not support the TI 4000M TravelMate and the ACER
2646	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2647	  desktop machines also don't have compliant BIOSes, and this driver
2648	  may cause those machines to panic during the boot phase.
2649
2650	  Generally, if you don't have a battery in your machine, there isn't
2651	  much point in using this driver and you should say N. If you get
2652	  random kernel OOPSes or reboots that don't seem to be related to
2653	  anything, try disabling/enabling this option (or disabling/enabling
2654	  APM in your BIOS).
2655
2656	  Some other things you should try when experiencing seemingly random,
2657	  "weird" problems:
2658
2659	  1) make sure that you have enough swap space and that it is
2660	  enabled.
2661	  2) pass the "idle=poll" option to the kernel
2662	  3) switch on floating point emulation in the kernel and pass
2663	  the "no387" option to the kernel
2664	  4) pass the "floppy=nodma" option to the kernel
2665	  5) pass the "mem=4M" option to the kernel (thereby disabling
2666	  all but the first 4 MB of RAM)
2667	  6) make sure that the CPU is not over clocked.
2668	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2669	  8) disable the cache from your BIOS settings
2670	  9) install a fan for the video card or exchange video RAM
2671	  10) install a better fan for the CPU
2672	  11) exchange RAM chips
2673	  12) exchange the motherboard.
2674
2675	  To compile this driver as a module, choose M here: the
2676	  module will be called apm.
2677
2678if APM
2679
2680config APM_IGNORE_USER_SUSPEND
2681	bool "Ignore USER SUSPEND"
2682	help
2683	  This option will ignore USER SUSPEND requests. On machines with a
2684	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2685	  series notebooks, it is necessary to say Y because of a BIOS bug.
2686
2687config APM_DO_ENABLE
2688	bool "Enable PM at boot time"
2689	help
2690	  Enable APM features at boot time. From page 36 of the APM BIOS
2691	  specification: "When disabled, the APM BIOS does not automatically
2692	  power manage devices, enter the Standby State, enter the Suspend
2693	  State, or take power saving steps in response to CPU Idle calls."
2694	  This driver will make CPU Idle calls when Linux is idle (unless this
2695	  feature is turned off -- see "Do CPU IDLE calls", below). This
2696	  should always save battery power, but more complicated APM features
2697	  will be dependent on your BIOS implementation. You may need to turn
2698	  this option off if your computer hangs at boot time when using APM
2699	  support, or if it beeps continuously instead of suspending. Turn
2700	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2701	  T400CDT. This is off by default since most machines do fine without
2702	  this feature.
2703
2704config APM_CPU_IDLE
2705	depends on CPU_IDLE
2706	bool "Make CPU Idle calls when idle"
2707	help
2708	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2709	  On some machines, this can activate improved power savings, such as
2710	  a slowed CPU clock rate, when the machine is idle. These idle calls
2711	  are made after the idle loop has run for some length of time (e.g.,
2712	  333 mS). On some machines, this will cause a hang at boot time or
2713	  whenever the CPU becomes idle. (On machines with more than one CPU,
2714	  this option does nothing.)
2715
2716config APM_DISPLAY_BLANK
2717	bool "Enable console blanking using APM"
2718	help
2719	  Enable console blanking using the APM. Some laptops can use this to
2720	  turn off the LCD backlight when the screen blanker of the Linux
2721	  virtual console blanks the screen. Note that this is only used by
2722	  the virtual console screen blanker, and won't turn off the backlight
2723	  when using the X Window system. This also doesn't have anything to
2724	  do with your VESA-compliant power-saving monitor. Further, this
2725	  option doesn't work for all laptops -- it might not turn off your
2726	  backlight at all, or it might print a lot of errors to the console,
2727	  especially if you are using gpm.
2728
2729config APM_ALLOW_INTS
2730	bool "Allow interrupts during APM BIOS calls"
2731	help
2732	  Normally we disable external interrupts while we are making calls to
2733	  the APM BIOS as a measure to lessen the effects of a badly behaving
2734	  BIOS implementation.  The BIOS should reenable interrupts if it
2735	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2736	  many of the newer IBM Thinkpads.  If you experience hangs when you
2737	  suspend, try setting this to Y.  Otherwise, say N.
2738
2739endif # APM
2740
2741source "drivers/cpufreq/Kconfig"
2742
2743source "drivers/cpuidle/Kconfig"
2744
2745source "drivers/idle/Kconfig"
2746
2747endmenu
2748
2749menu "Bus options (PCI etc.)"
2750
2751choice
2752	prompt "PCI access mode"
2753	depends on X86_32 && PCI
2754	default PCI_GOANY
2755	help
2756	  On PCI systems, the BIOS can be used to detect the PCI devices and
2757	  determine their configuration. However, some old PCI motherboards
2758	  have BIOS bugs and may crash if this is done. Also, some embedded
2759	  PCI-based systems don't have any BIOS at all. Linux can also try to
2760	  detect the PCI hardware directly without using the BIOS.
2761
2762	  With this option, you can specify how Linux should detect the
2763	  PCI devices. If you choose "BIOS", the BIOS will be used,
2764	  if you choose "Direct", the BIOS won't be used, and if you
2765	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2766	  If you choose "Any", the kernel will try MMCONFIG, then the
2767	  direct access method and falls back to the BIOS if that doesn't
2768	  work. If unsure, go with the default, which is "Any".
2769
2770config PCI_GOBIOS
2771	bool "BIOS"
2772
2773config PCI_GOMMCONFIG
2774	bool "MMConfig"
2775
2776config PCI_GODIRECT
2777	bool "Direct"
2778
2779config PCI_GOOLPC
2780	bool "OLPC XO-1"
2781	depends on OLPC
2782
2783config PCI_GOANY
2784	bool "Any"
2785
2786endchoice
2787
2788config PCI_BIOS
2789	def_bool y
2790	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2791
2792# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2793config PCI_DIRECT
2794	def_bool y
2795	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2796
2797config PCI_MMCONFIG
2798	bool "Support mmconfig PCI config space access" if X86_64
2799	default y
2800	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2801	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2802
2803config PCI_OLPC
2804	def_bool y
2805	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2806
2807config PCI_XEN
2808	def_bool y
2809	depends on PCI && XEN
2810
2811config MMCONF_FAM10H
2812	def_bool y
2813	depends on X86_64 && PCI_MMCONFIG && ACPI
2814
2815config PCI_CNB20LE_QUIRK
2816	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2817	depends on PCI
2818	help
2819	  Read the PCI windows out of the CNB20LE host bridge. This allows
2820	  PCI hotplug to work on systems with the CNB20LE chipset which do
2821	  not have ACPI.
2822
2823	  There's no public spec for this chipset, and this functionality
2824	  is known to be incomplete.
2825
2826	  You should say N unless you know you need this.
2827
2828config ISA_BUS
2829	bool "ISA bus support on modern systems" if EXPERT
2830	help
2831	  Expose ISA bus device drivers and options available for selection and
2832	  configuration. Enable this option if your target machine has an ISA
2833	  bus. ISA is an older system, displaced by PCI and newer bus
2834	  architectures -- if your target machine is modern, it probably does
2835	  not have an ISA bus.
2836
2837	  If unsure, say N.
2838
2839# x86_64 have no ISA slots, but can have ISA-style DMA.
2840config ISA_DMA_API
2841	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2842	default y
2843	help
2844	  Enables ISA-style DMA support for devices requiring such controllers.
2845	  If unsure, say Y.
2846
2847if X86_32
2848
2849config ISA
2850	bool "ISA support"
2851	help
2852	  Find out whether you have ISA slots on your motherboard.  ISA is the
2853	  name of a bus system, i.e. the way the CPU talks to the other stuff
2854	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2855	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2856	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2857
2858config SCx200
2859	tristate "NatSemi SCx200 support"
2860	help
2861	  This provides basic support for National Semiconductor's
2862	  (now AMD's) Geode processors.  The driver probes for the
2863	  PCI-IDs of several on-chip devices, so its a good dependency
2864	  for other scx200_* drivers.
2865
2866	  If compiled as a module, the driver is named scx200.
2867
2868config SCx200HR_TIMER
2869	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2870	depends on SCx200
2871	default y
2872	help
2873	  This driver provides a clocksource built upon the on-chip
2874	  27MHz high-resolution timer.  Its also a workaround for
2875	  NSC Geode SC-1100's buggy TSC, which loses time when the
2876	  processor goes idle (as is done by the scheduler).  The
2877	  other workaround is idle=poll boot option.
2878
2879config OLPC
2880	bool "One Laptop Per Child support"
2881	depends on !X86_PAE
2882	select GPIOLIB
2883	select OF
2884	select OF_PROMTREE
2885	select IRQ_DOMAIN
2886	select OLPC_EC
2887	help
2888	  Add support for detecting the unique features of the OLPC
2889	  XO hardware.
2890
2891config OLPC_XO1_PM
2892	bool "OLPC XO-1 Power Management"
2893	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2894	help
2895	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2896
2897config OLPC_XO1_RTC
2898	bool "OLPC XO-1 Real Time Clock"
2899	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2900	help
2901	  Add support for the XO-1 real time clock, which can be used as a
2902	  programmable wakeup source.
2903
2904config OLPC_XO1_SCI
2905	bool "OLPC XO-1 SCI extras"
2906	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2907	depends on INPUT=y
2908	select POWER_SUPPLY
2909	help
2910	  Add support for SCI-based features of the OLPC XO-1 laptop:
2911	   - EC-driven system wakeups
2912	   - Power button
2913	   - Ebook switch
2914	   - Lid switch
2915	   - AC adapter status updates
2916	   - Battery status updates
2917
2918config OLPC_XO15_SCI
2919	bool "OLPC XO-1.5 SCI extras"
2920	depends on OLPC && ACPI
2921	select POWER_SUPPLY
2922	help
2923	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2924	   - EC-driven system wakeups
2925	   - AC adapter status updates
2926	   - Battery status updates
2927
2928config ALIX
2929	bool "PCEngines ALIX System Support (LED setup)"
2930	select GPIOLIB
2931	help
2932	  This option enables system support for the PCEngines ALIX.
2933	  At present this just sets up LEDs for GPIO control on
2934	  ALIX2/3/6 boards.  However, other system specific setup should
2935	  get added here.
2936
2937	  Note: You must still enable the drivers for GPIO and LED support
2938	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2939
2940	  Note: You have to set alix.force=1 for boards with Award BIOS.
2941
2942config NET5501
2943	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2944	select GPIOLIB
2945	help
2946	  This option enables system support for the Soekris Engineering net5501.
2947
2948config GEOS
2949	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2950	select GPIOLIB
2951	depends on DMI
2952	help
2953	  This option enables system support for the Traverse Technologies GEOS.
2954
2955config TS5500
2956	bool "Technologic Systems TS-5500 platform support"
2957	depends on MELAN
2958	select CHECK_SIGNATURE
2959	select NEW_LEDS
2960	select LEDS_CLASS
2961	help
2962	  This option enables system support for the Technologic Systems TS-5500.
2963
2964endif # X86_32
2965
2966config AMD_NB
2967	def_bool y
2968	depends on CPU_SUP_AMD && PCI
2969
2970endmenu
2971
2972menu "Binary Emulations"
2973
2974config IA32_EMULATION
2975	bool "IA32 Emulation"
2976	depends on X86_64
2977	select ARCH_WANT_OLD_COMPAT_IPC
2978	select BINFMT_ELF
2979	select COMPAT_OLD_SIGACTION
2980	help
2981	  Include code to run legacy 32-bit programs under a
2982	  64-bit kernel. You should likely turn this on, unless you're
2983	  100% sure that you don't have any 32-bit programs left.
2984
2985config X86_X32_ABI
2986	bool "x32 ABI for 64-bit mode"
2987	depends on X86_64
2988	# llvm-objcopy does not convert x86_64 .note.gnu.property or
2989	# compressed debug sections to x86_x32 properly:
2990	# https://github.com/ClangBuiltLinux/linux/issues/514
2991	# https://github.com/ClangBuiltLinux/linux/issues/1141
2992	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
2993	help
2994	  Include code to run binaries for the x32 native 32-bit ABI
2995	  for 64-bit processors.  An x32 process gets access to the
2996	  full 64-bit register file and wide data path while leaving
2997	  pointers at 32 bits for smaller memory footprint.
2998
2999config COMPAT_32
3000	def_bool y
3001	depends on IA32_EMULATION || X86_32
3002	select HAVE_UID16
3003	select OLD_SIGSUSPEND3
3004
3005config COMPAT
3006	def_bool y
3007	depends on IA32_EMULATION || X86_X32_ABI
3008
3009config COMPAT_FOR_U64_ALIGNMENT
3010	def_bool y
3011	depends on COMPAT
3012
3013endmenu
3014
3015config HAVE_ATOMIC_IOMAP
3016	def_bool y
3017	depends on X86_32
3018
3019source "arch/x86/kvm/Kconfig"
3020
3021source "arch/x86/Kconfig.assembler"
3022