xref: /linux/arch/x86/Kconfig (revision 3cc0c3738cde66a1eadf977fa7b2fdecbbcf5d4f)
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_CURRENT_STACK_POINTER
75	select ARCH_HAS_DEBUG_VIRTUAL
76	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
77	select ARCH_HAS_DEVMEM_IS_ALLOWED
78	select ARCH_HAS_EARLY_DEBUG		if KGDB
79	select ARCH_HAS_ELF_RANDOMIZE
80	select ARCH_HAS_FAST_MULTIPLIER
81	select ARCH_HAS_FORTIFY_SOURCE
82	select ARCH_HAS_GCOV_PROFILE_ALL
83	select ARCH_HAS_KCOV			if X86_64
84	select ARCH_HAS_MEM_ENCRYPT
85	select ARCH_HAS_MEMBARRIER_SYNC_CORE
86	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
87	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
88	select ARCH_HAS_PMEM_API		if X86_64
89	select ARCH_HAS_PTE_DEVMAP		if X86_64
90	select ARCH_HAS_PTE_SPECIAL
91	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
92	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
93	select ARCH_HAS_COPY_MC			if X86_64
94	select ARCH_HAS_SET_MEMORY
95	select ARCH_HAS_SET_DIRECT_MAP
96	select ARCH_HAS_STRICT_KERNEL_RWX
97	select ARCH_HAS_STRICT_MODULE_RWX
98	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
99	select ARCH_HAS_SYSCALL_WRAPPER
100	select ARCH_HAS_UBSAN_SANITIZE_ALL
101	select ARCH_HAS_DEBUG_WX
102	select ARCH_HAS_ZONE_DMA_SET if EXPERT
103	select ARCH_HAVE_NMI_SAFE_CMPXCHG
104	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
105	select ARCH_MIGHT_HAVE_PC_PARPORT
106	select ARCH_MIGHT_HAVE_PC_SERIO
107	select ARCH_STACKWALK
108	select ARCH_SUPPORTS_ACPI
109	select ARCH_SUPPORTS_ATOMIC_RMW
110	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
111	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
112	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
113	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
114	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
115	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
116	select ARCH_SUPPORTS_LTO_CLANG
117	select ARCH_SUPPORTS_LTO_CLANG_THIN
118	select ARCH_USE_BUILTIN_BSWAP
119	select ARCH_USE_MEMTEST
120	select ARCH_USE_QUEUED_RWLOCKS
121	select ARCH_USE_QUEUED_SPINLOCKS
122	select ARCH_USE_SYM_ANNOTATIONS
123	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
124	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
125	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
126	select ARCH_WANTS_NO_INSTR
127	select ARCH_WANT_GENERAL_HUGETLB
128	select ARCH_WANT_HUGE_PMD_SHARE
129	select ARCH_WANT_LD_ORPHAN_WARN
130	select ARCH_WANT_OPTIMIZE_VMEMMAP	if X86_64
131	select ARCH_WANTS_THP_SWAP		if X86_64
132	select ARCH_HAS_PARANOID_L1D_FLUSH
133	select BUILDTIME_TABLE_SORT
134	select CLKEVT_I8253
135	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
136	select CLOCKSOURCE_WATCHDOG
137	# Word-size accesses may read uninitialized data past the trailing \0
138	# in strings and cause false KMSAN reports.
139	select DCACHE_WORD_ACCESS		if !KMSAN
140	select DYNAMIC_SIGFRAME
141	select EDAC_ATOMIC_SCRUB
142	select EDAC_SUPPORT
143	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
144	select GENERIC_CLOCKEVENTS_MIN_ADJUST
145	select GENERIC_CMOS_UPDATE
146	select GENERIC_CPU_AUTOPROBE
147	select GENERIC_CPU_VULNERABILITIES
148	select GENERIC_EARLY_IOREMAP
149	select GENERIC_ENTRY
150	select GENERIC_IOMAP
151	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
152	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
153	select GENERIC_IRQ_MIGRATION		if SMP
154	select GENERIC_IRQ_PROBE
155	select GENERIC_IRQ_RESERVATION_MODE
156	select GENERIC_IRQ_SHOW
157	select GENERIC_PENDING_IRQ		if SMP
158	select GENERIC_PTDUMP
159	select GENERIC_SMP_IDLE_THREAD
160	select GENERIC_TIME_VSYSCALL
161	select GENERIC_GETTIMEOFDAY
162	select GENERIC_VDSO_TIME_NS
163	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
164	select HARDIRQS_SW_RESEND
165	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
166	select HAVE_ACPI_APEI			if ACPI
167	select HAVE_ACPI_APEI_NMI		if ACPI
168	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
169	select HAVE_ARCH_AUDITSYSCALL
170	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
171	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
172	select HAVE_ARCH_JUMP_LABEL
173	select HAVE_ARCH_JUMP_LABEL_RELATIVE
174	select HAVE_ARCH_KASAN			if X86_64
175	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
176	select HAVE_ARCH_KFENCE
177	select HAVE_ARCH_KMSAN			if X86_64
178	select HAVE_ARCH_KGDB
179	select HAVE_ARCH_MMAP_RND_BITS		if MMU
180	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
181	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
182	select HAVE_ARCH_PREL32_RELOCATIONS
183	select HAVE_ARCH_SECCOMP_FILTER
184	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
185	select HAVE_ARCH_STACKLEAK
186	select HAVE_ARCH_TRACEHOOK
187	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
188	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
189	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
190	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
191	select HAVE_ARCH_VMAP_STACK		if X86_64
192	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
193	select HAVE_ARCH_WITHIN_STACK_FRAMES
194	select HAVE_ASM_MODVERSIONS
195	select HAVE_CMPXCHG_DOUBLE
196	select HAVE_CMPXCHG_LOCAL
197	select HAVE_CONTEXT_TRACKING_USER		if X86_64
198	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
199	select HAVE_C_RECORDMCOUNT
200	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
201	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
202	select HAVE_BUILDTIME_MCOUNT_SORT
203	select HAVE_DEBUG_KMEMLEAK
204	select HAVE_DMA_CONTIGUOUS
205	select HAVE_DYNAMIC_FTRACE
206	select HAVE_DYNAMIC_FTRACE_WITH_REGS
207	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
208	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
209	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
210	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
211	select HAVE_EBPF_JIT
212	select HAVE_EFFICIENT_UNALIGNED_ACCESS
213	select HAVE_EISA
214	select HAVE_EXIT_THREAD
215	select HAVE_FAST_GUP
216	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
217	select HAVE_FTRACE_MCOUNT_RECORD
218	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
219	select HAVE_FUNCTION_TRACER
220	select HAVE_GCC_PLUGINS
221	select HAVE_HW_BREAKPOINT
222	select HAVE_IOREMAP_PROT
223	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
224	select HAVE_IRQ_TIME_ACCOUNTING
225	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
226	select HAVE_KERNEL_BZIP2
227	select HAVE_KERNEL_GZIP
228	select HAVE_KERNEL_LZ4
229	select HAVE_KERNEL_LZMA
230	select HAVE_KERNEL_LZO
231	select HAVE_KERNEL_XZ
232	select HAVE_KERNEL_ZSTD
233	select HAVE_KPROBES
234	select HAVE_KPROBES_ON_FTRACE
235	select HAVE_FUNCTION_ERROR_INJECTION
236	select HAVE_KRETPROBES
237	select HAVE_RETHOOK
238	select HAVE_KVM
239	select HAVE_LIVEPATCH			if X86_64
240	select HAVE_MIXED_BREAKPOINTS_REGS
241	select HAVE_MOD_ARCH_SPECIFIC
242	select HAVE_MOVE_PMD
243	select HAVE_MOVE_PUD
244	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
245	select HAVE_NMI
246	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
247	select HAVE_OBJTOOL			if X86_64
248	select HAVE_OPTPROBES
249	select HAVE_PCSPKR_PLATFORM
250	select HAVE_PERF_EVENTS
251	select HAVE_PERF_EVENTS_NMI
252	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
253	select HAVE_PCI
254	select HAVE_PERF_REGS
255	select HAVE_PERF_USER_STACK_DUMP
256	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
257	select MMU_GATHER_MERGE_VMAS
258	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
259	select HAVE_REGS_AND_STACK_ACCESS_API
260	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
261	select HAVE_FUNCTION_ARG_ACCESS_API
262	select HAVE_SETUP_PER_CPU_AREA
263	select HAVE_SOFTIRQ_ON_OWN_STACK
264	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
265	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
266	select HAVE_STATIC_CALL
267	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
268	select HAVE_PREEMPT_DYNAMIC_CALL
269	select HAVE_RSEQ
270	select HAVE_RUST			if X86_64
271	select HAVE_SYSCALL_TRACEPOINTS
272	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
273	select HAVE_UNSTABLE_SCHED_CLOCK
274	select HAVE_USER_RETURN_NOTIFIER
275	select HAVE_GENERIC_VDSO
276	select HOTPLUG_SMT			if SMP
277	select IRQ_FORCED_THREADING
278	select NEED_PER_CPU_EMBED_FIRST_CHUNK
279	select NEED_PER_CPU_PAGE_FIRST_CHUNK
280	select NEED_SG_DMA_LENGTH
281	select PCI_DOMAINS			if PCI
282	select PCI_LOCKLESS_CONFIG		if PCI
283	select PERF_EVENTS
284	select RTC_LIB
285	select RTC_MC146818_LIB
286	select SPARSE_IRQ
287	select SRCU
288	select SYSCTL_EXCEPTION_TRACE
289	select THREAD_INFO_IN_TASK
290	select TRACE_IRQFLAGS_SUPPORT
291	select TRACE_IRQFLAGS_NMI_SUPPORT
292	select USER_STACKTRACE_SUPPORT
293	select HAVE_ARCH_KCSAN			if X86_64
294	select X86_FEATURE_NAMES		if PROC_FS
295	select PROC_PID_ARCH_STATUS		if PROC_FS
296	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
297	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
298	select FUNCTION_ALIGNMENT_4B
299	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
300	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
301
302config INSTRUCTION_DECODER
303	def_bool y
304	depends on KPROBES || PERF_EVENTS || UPROBES
305
306config OUTPUT_FORMAT
307	string
308	default "elf32-i386" if X86_32
309	default "elf64-x86-64" if X86_64
310
311config LOCKDEP_SUPPORT
312	def_bool y
313
314config STACKTRACE_SUPPORT
315	def_bool y
316
317config MMU
318	def_bool y
319
320config ARCH_MMAP_RND_BITS_MIN
321	default 28 if 64BIT
322	default 8
323
324config ARCH_MMAP_RND_BITS_MAX
325	default 32 if 64BIT
326	default 16
327
328config ARCH_MMAP_RND_COMPAT_BITS_MIN
329	default 8
330
331config ARCH_MMAP_RND_COMPAT_BITS_MAX
332	default 16
333
334config SBUS
335	bool
336
337config GENERIC_ISA_DMA
338	def_bool y
339	depends on ISA_DMA_API
340
341config GENERIC_CSUM
342	bool
343	default y if KMSAN || KASAN
344
345config GENERIC_BUG
346	def_bool y
347	depends on BUG
348	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
349
350config GENERIC_BUG_RELATIVE_POINTERS
351	bool
352
353config ARCH_MAY_HAVE_PC_FDC
354	def_bool y
355	depends on ISA_DMA_API
356
357config GENERIC_CALIBRATE_DELAY
358	def_bool y
359
360config ARCH_HAS_CPU_RELAX
361	def_bool y
362
363config ARCH_HIBERNATION_POSSIBLE
364	def_bool y
365
366config ARCH_SUSPEND_POSSIBLE
367	def_bool y
368
369config AUDIT_ARCH
370	def_bool y if X86_64
371
372config KASAN_SHADOW_OFFSET
373	hex
374	depends on KASAN
375	default 0xdffffc0000000000
376
377config HAVE_INTEL_TXT
378	def_bool y
379	depends on INTEL_IOMMU && ACPI
380
381config X86_32_SMP
382	def_bool y
383	depends on X86_32 && SMP
384
385config X86_64_SMP
386	def_bool y
387	depends on X86_64 && SMP
388
389config ARCH_SUPPORTS_UPROBES
390	def_bool y
391
392config FIX_EARLYCON_MEM
393	def_bool y
394
395config DYNAMIC_PHYSICAL_MASK
396	bool
397
398config PGTABLE_LEVELS
399	int
400	default 5 if X86_5LEVEL
401	default 4 if X86_64
402	default 3 if X86_PAE
403	default 2
404
405config CC_HAS_SANE_STACKPROTECTOR
406	bool
407	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
408	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
409	help
410	  We have to make sure stack protector is unconditionally disabled if
411	  the compiler produces broken code or if it does not let us control
412	  the segment on 32-bit kernels.
413
414menu "Processor type and features"
415
416config SMP
417	bool "Symmetric multi-processing support"
418	help
419	  This enables support for systems with more than one CPU. If you have
420	  a system with only one CPU, say N. If you have a system with more
421	  than one CPU, say Y.
422
423	  If you say N here, the kernel will run on uni- and multiprocessor
424	  machines, but will use only one CPU of a multiprocessor machine. If
425	  you say Y here, the kernel will run on many, but not all,
426	  uniprocessor machines. On a uniprocessor machine, the kernel
427	  will run faster if you say N here.
428
429	  Note that if you say Y here and choose architecture "586" or
430	  "Pentium" under "Processor family", the kernel will not work on 486
431	  architectures. Similarly, multiprocessor kernels for the "PPro"
432	  architecture may not work on all Pentium based boards.
433
434	  People using multiprocessor machines who say Y here should also say
435	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
436	  Management" code will be disabled if you say Y here.
437
438	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
439	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
440	  <http://www.tldp.org/docs.html#howto>.
441
442	  If you don't know what to do here, say N.
443
444config X86_FEATURE_NAMES
445	bool "Processor feature human-readable names" if EMBEDDED
446	default y
447	help
448	  This option compiles in a table of x86 feature bits and corresponding
449	  names.  This is required to support /proc/cpuinfo and a few kernel
450	  messages.  You can disable this to save space, at the expense of
451	  making those few kernel messages show numeric feature bits instead.
452
453	  If in doubt, say Y.
454
455config X86_X2APIC
456	bool "Support x2apic"
457	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
458	help
459	  This enables x2apic support on CPUs that have this feature.
460
461	  This allows 32-bit apic IDs (so it can support very large systems),
462	  and accesses the local apic via MSRs not via mmio.
463
464	  Some Intel systems circa 2022 and later are locked into x2APIC mode
465	  and can not fall back to the legacy APIC modes if SGX or TDX are
466	  enabled in the BIOS. They will boot with very reduced functionality
467	  without enabling this option.
468
469	  If you don't know what to do here, say N.
470
471config X86_MPPARSE
472	bool "Enable MPS table" if ACPI
473	default y
474	depends on X86_LOCAL_APIC
475	help
476	  For old smp systems that do not have proper acpi support. Newer systems
477	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
478
479config GOLDFISH
480	def_bool y
481	depends on X86_GOLDFISH
482
483config X86_CPU_RESCTRL
484	bool "x86 CPU resource control support"
485	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
486	select KERNFS
487	select PROC_CPU_RESCTRL		if PROC_FS
488	help
489	  Enable x86 CPU resource control support.
490
491	  Provide support for the allocation and monitoring of system resources
492	  usage by the CPU.
493
494	  Intel calls this Intel Resource Director Technology
495	  (Intel(R) RDT). More information about RDT can be found in the
496	  Intel x86 Architecture Software Developer Manual.
497
498	  AMD calls this AMD Platform Quality of Service (AMD QoS).
499	  More information about AMD QoS can be found in the AMD64 Technology
500	  Platform Quality of Service Extensions manual.
501
502	  Say N if unsure.
503
504if X86_32
505config X86_BIGSMP
506	bool "Support for big SMP systems with more than 8 CPUs"
507	depends on SMP
508	help
509	  This option is needed for the systems that have more than 8 CPUs.
510
511config X86_EXTENDED_PLATFORM
512	bool "Support for extended (non-PC) x86 platforms"
513	default y
514	help
515	  If you disable this option then the kernel will only support
516	  standard PC platforms. (which covers the vast majority of
517	  systems out there.)
518
519	  If you enable this option then you'll be able to select support
520	  for the following (non-PC) 32 bit x86 platforms:
521		Goldfish (Android emulator)
522		AMD Elan
523		RDC R-321x SoC
524		SGI 320/540 (Visual Workstation)
525		STA2X11-based (e.g. Northville)
526		Moorestown MID devices
527
528	  If you have one of these systems, or if you want to build a
529	  generic distribution kernel, say Y here - otherwise say N.
530endif # X86_32
531
532if X86_64
533config X86_EXTENDED_PLATFORM
534	bool "Support for extended (non-PC) x86 platforms"
535	default y
536	help
537	  If you disable this option then the kernel will only support
538	  standard PC platforms. (which covers the vast majority of
539	  systems out there.)
540
541	  If you enable this option then you'll be able to select support
542	  for the following (non-PC) 64 bit x86 platforms:
543		Numascale NumaChip
544		ScaleMP vSMP
545		SGI Ultraviolet
546
547	  If you have one of these systems, or if you want to build a
548	  generic distribution kernel, say Y here - otherwise say N.
549endif # X86_64
550# This is an alphabetically sorted list of 64 bit extended platforms
551# Please maintain the alphabetic order if and when there are additions
552config X86_NUMACHIP
553	bool "Numascale NumaChip"
554	depends on X86_64
555	depends on X86_EXTENDED_PLATFORM
556	depends on NUMA
557	depends on SMP
558	depends on X86_X2APIC
559	depends on PCI_MMCONFIG
560	help
561	  Adds support for Numascale NumaChip large-SMP systems. Needed to
562	  enable more than ~168 cores.
563	  If you don't have one of these, you should say N here.
564
565config X86_VSMP
566	bool "ScaleMP vSMP"
567	select HYPERVISOR_GUEST
568	select PARAVIRT
569	depends on X86_64 && PCI
570	depends on X86_EXTENDED_PLATFORM
571	depends on SMP
572	help
573	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
574	  supposed to run on these EM64T-based machines.  Only choose this option
575	  if you have one of these machines.
576
577config X86_UV
578	bool "SGI Ultraviolet"
579	depends on X86_64
580	depends on X86_EXTENDED_PLATFORM
581	depends on NUMA
582	depends on EFI
583	depends on KEXEC_CORE
584	depends on X86_X2APIC
585	depends on PCI
586	help
587	  This option is needed in order to support SGI Ultraviolet systems.
588	  If you don't have one of these, you should say N here.
589
590# Following is an alphabetically sorted list of 32 bit extended platforms
591# Please maintain the alphabetic order if and when there are additions
592
593config X86_GOLDFISH
594	bool "Goldfish (Virtual Platform)"
595	depends on X86_EXTENDED_PLATFORM
596	help
597	  Enable support for the Goldfish virtual platform used primarily
598	  for Android development. Unless you are building for the Android
599	  Goldfish emulator say N here.
600
601config X86_INTEL_CE
602	bool "CE4100 TV platform"
603	depends on PCI
604	depends on PCI_GODIRECT
605	depends on X86_IO_APIC
606	depends on X86_32
607	depends on X86_EXTENDED_PLATFORM
608	select X86_REBOOTFIXUPS
609	select OF
610	select OF_EARLY_FLATTREE
611	help
612	  Select for the Intel CE media processor (CE4100) SOC.
613	  This option compiles in support for the CE4100 SOC for settop
614	  boxes and media devices.
615
616config X86_INTEL_MID
617	bool "Intel MID platform support"
618	depends on X86_EXTENDED_PLATFORM
619	depends on X86_PLATFORM_DEVICES
620	depends on PCI
621	depends on X86_64 || (PCI_GOANY && X86_32)
622	depends on X86_IO_APIC
623	select I2C
624	select DW_APB_TIMER
625	select INTEL_SCU_PCI
626	help
627	  Select to build a kernel capable of supporting Intel MID (Mobile
628	  Internet Device) platform systems which do not have the PCI legacy
629	  interfaces. If you are building for a PC class system say N here.
630
631	  Intel MID platforms are based on an Intel processor and chipset which
632	  consume less power than most of the x86 derivatives.
633
634config X86_INTEL_QUARK
635	bool "Intel Quark platform support"
636	depends on X86_32
637	depends on X86_EXTENDED_PLATFORM
638	depends on X86_PLATFORM_DEVICES
639	depends on X86_TSC
640	depends on PCI
641	depends on PCI_GOANY
642	depends on X86_IO_APIC
643	select IOSF_MBI
644	select INTEL_IMR
645	select COMMON_CLK
646	help
647	  Select to include support for Quark X1000 SoC.
648	  Say Y here if you have a Quark based system such as the Arduino
649	  compatible Intel Galileo.
650
651config X86_INTEL_LPSS
652	bool "Intel Low Power Subsystem Support"
653	depends on X86 && ACPI && PCI
654	select COMMON_CLK
655	select PINCTRL
656	select IOSF_MBI
657	help
658	  Select to build support for Intel Low Power Subsystem such as
659	  found on Intel Lynxpoint PCH. Selecting this option enables
660	  things like clock tree (common clock framework) and pincontrol
661	  which are needed by the LPSS peripheral drivers.
662
663config X86_AMD_PLATFORM_DEVICE
664	bool "AMD ACPI2Platform devices support"
665	depends on ACPI
666	select COMMON_CLK
667	select PINCTRL
668	help
669	  Select to interpret AMD specific ACPI device to platform device
670	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
671	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
672	  implemented under PINCTRL subsystem.
673
674config IOSF_MBI
675	tristate "Intel SoC IOSF Sideband support for SoC platforms"
676	depends on PCI
677	help
678	  This option enables sideband register access support for Intel SoC
679	  platforms. On these platforms the IOSF sideband is used in lieu of
680	  MSR's for some register accesses, mostly but not limited to thermal
681	  and power. Drivers may query the availability of this device to
682	  determine if they need the sideband in order to work on these
683	  platforms. The sideband is available on the following SoC products.
684	  This list is not meant to be exclusive.
685	   - BayTrail
686	   - Braswell
687	   - Quark
688
689	  You should say Y if you are running a kernel on one of these SoC's.
690
691config IOSF_MBI_DEBUG
692	bool "Enable IOSF sideband access through debugfs"
693	depends on IOSF_MBI && DEBUG_FS
694	help
695	  Select this option to expose the IOSF sideband access registers (MCR,
696	  MDR, MCRX) through debugfs to write and read register information from
697	  different units on the SoC. This is most useful for obtaining device
698	  state information for debug and analysis. As this is a general access
699	  mechanism, users of this option would have specific knowledge of the
700	  device they want to access.
701
702	  If you don't require the option or are in doubt, say N.
703
704config X86_RDC321X
705	bool "RDC R-321x SoC"
706	depends on X86_32
707	depends on X86_EXTENDED_PLATFORM
708	select M486
709	select X86_REBOOTFIXUPS
710	help
711	  This option is needed for RDC R-321x system-on-chip, also known
712	  as R-8610-(G).
713	  If you don't have one of these chips, you should say N here.
714
715config X86_32_NON_STANDARD
716	bool "Support non-standard 32-bit SMP architectures"
717	depends on X86_32 && SMP
718	depends on X86_EXTENDED_PLATFORM
719	help
720	  This option compiles in the bigsmp and STA2X11 default
721	  subarchitectures.  It is intended for a generic binary
722	  kernel. If you select them all, kernel will probe it one by
723	  one and will fallback to default.
724
725# Alphabetically sorted list of Non standard 32 bit platforms
726
727config X86_SUPPORTS_MEMORY_FAILURE
728	def_bool y
729	# MCE code calls memory_failure():
730	depends on X86_MCE
731	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
732	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
733	depends on X86_64 || !SPARSEMEM
734	select ARCH_SUPPORTS_MEMORY_FAILURE
735
736config STA2X11
737	bool "STA2X11 Companion Chip Support"
738	depends on X86_32_NON_STANDARD && PCI
739	select SWIOTLB
740	select MFD_STA2X11
741	select GPIOLIB
742	help
743	  This adds support for boards based on the STA2X11 IO-Hub,
744	  a.k.a. "ConneXt". The chip is used in place of the standard
745	  PC chipset, so all "standard" peripherals are missing. If this
746	  option is selected the kernel will still be able to boot on
747	  standard PC machines.
748
749config X86_32_IRIS
750	tristate "Eurobraille/Iris poweroff module"
751	depends on X86_32
752	help
753	  The Iris machines from EuroBraille do not have APM or ACPI support
754	  to shut themselves down properly.  A special I/O sequence is
755	  needed to do so, which is what this module does at
756	  kernel shutdown.
757
758	  This is only for Iris machines from EuroBraille.
759
760	  If unused, say N.
761
762config SCHED_OMIT_FRAME_POINTER
763	def_bool y
764	prompt "Single-depth WCHAN output"
765	depends on X86
766	help
767	  Calculate simpler /proc/<PID>/wchan values. If this option
768	  is disabled then wchan values will recurse back to the
769	  caller function. This provides more accurate wchan values,
770	  at the expense of slightly more scheduling overhead.
771
772	  If in doubt, say "Y".
773
774menuconfig HYPERVISOR_GUEST
775	bool "Linux guest support"
776	help
777	  Say Y here to enable options for running Linux under various hyper-
778	  visors. This option enables basic hypervisor detection and platform
779	  setup.
780
781	  If you say N, all options in this submenu will be skipped and
782	  disabled, and Linux guest support won't be built in.
783
784if HYPERVISOR_GUEST
785
786config PARAVIRT
787	bool "Enable paravirtualization code"
788	depends on HAVE_STATIC_CALL
789	help
790	  This changes the kernel so it can modify itself when it is run
791	  under a hypervisor, potentially improving performance significantly
792	  over full virtualization.  However, when run without a hypervisor
793	  the kernel is theoretically slower and slightly larger.
794
795config PARAVIRT_XXL
796	bool
797
798config PARAVIRT_DEBUG
799	bool "paravirt-ops debugging"
800	depends on PARAVIRT && DEBUG_KERNEL
801	help
802	  Enable to debug paravirt_ops internals.  Specifically, BUG if
803	  a paravirt_op is missing when it is called.
804
805config PARAVIRT_SPINLOCKS
806	bool "Paravirtualization layer for spinlocks"
807	depends on PARAVIRT && SMP
808	help
809	  Paravirtualized spinlocks allow a pvops backend to replace the
810	  spinlock implementation with something virtualization-friendly
811	  (for example, block the virtual CPU rather than spinning).
812
813	  It has a minimal impact on native kernels and gives a nice performance
814	  benefit on paravirtualized KVM / Xen kernels.
815
816	  If you are unsure how to answer this question, answer Y.
817
818config X86_HV_CALLBACK_VECTOR
819	def_bool n
820
821source "arch/x86/xen/Kconfig"
822
823config KVM_GUEST
824	bool "KVM Guest support (including kvmclock)"
825	depends on PARAVIRT
826	select PARAVIRT_CLOCK
827	select ARCH_CPUIDLE_HALTPOLL
828	select X86_HV_CALLBACK_VECTOR
829	default y
830	help
831	  This option enables various optimizations for running under the KVM
832	  hypervisor. It includes a paravirtualized clock, so that instead
833	  of relying on a PIT (or probably other) emulation by the
834	  underlying device model, the host provides the guest with
835	  timing infrastructure such as time of day, and system time
836
837config ARCH_CPUIDLE_HALTPOLL
838	def_bool n
839	prompt "Disable host haltpoll when loading haltpoll driver"
840	help
841	  If virtualized under KVM, disable host haltpoll.
842
843config PVH
844	bool "Support for running PVH guests"
845	help
846	  This option enables the PVH entry point for guest virtual machines
847	  as specified in the x86/HVM direct boot ABI.
848
849config PARAVIRT_TIME_ACCOUNTING
850	bool "Paravirtual steal time accounting"
851	depends on PARAVIRT
852	help
853	  Select this option to enable fine granularity task steal time
854	  accounting. Time spent executing other tasks in parallel with
855	  the current vCPU is discounted from the vCPU power. To account for
856	  that, there can be a small performance impact.
857
858	  If in doubt, say N here.
859
860config PARAVIRT_CLOCK
861	bool
862
863config JAILHOUSE_GUEST
864	bool "Jailhouse non-root cell support"
865	depends on X86_64 && PCI
866	select X86_PM_TIMER
867	help
868	  This option allows to run Linux as guest in a Jailhouse non-root
869	  cell. You can leave this option disabled if you only want to start
870	  Jailhouse and run Linux afterwards in the root cell.
871
872config ACRN_GUEST
873	bool "ACRN Guest support"
874	depends on X86_64
875	select X86_HV_CALLBACK_VECTOR
876	help
877	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
878	  a flexible, lightweight reference open-source hypervisor, built with
879	  real-time and safety-criticality in mind. It is built for embedded
880	  IOT with small footprint and real-time features. More details can be
881	  found in https://projectacrn.org/.
882
883config INTEL_TDX_GUEST
884	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
885	depends on X86_64 && CPU_SUP_INTEL
886	depends on X86_X2APIC
887	select ARCH_HAS_CC_PLATFORM
888	select X86_MEM_ENCRYPT
889	select X86_MCE
890	help
891	  Support running as a guest under Intel TDX.  Without this support,
892	  the guest kernel can not boot or run under TDX.
893	  TDX includes memory encryption and integrity capabilities
894	  which protect the confidentiality and integrity of guest
895	  memory contents and CPU state. TDX guests are protected from
896	  some attacks from the VMM.
897
898endif # HYPERVISOR_GUEST
899
900source "arch/x86/Kconfig.cpu"
901
902config HPET_TIMER
903	def_bool X86_64
904	prompt "HPET Timer Support" if X86_32
905	help
906	  Use the IA-PC HPET (High Precision Event Timer) to manage
907	  time in preference to the PIT and RTC, if a HPET is
908	  present.
909	  HPET is the next generation timer replacing legacy 8254s.
910	  The HPET provides a stable time base on SMP
911	  systems, unlike the TSC, but it is more expensive to access,
912	  as it is off-chip.  The interface used is documented
913	  in the HPET spec, revision 1.
914
915	  You can safely choose Y here.  However, HPET will only be
916	  activated if the platform and the BIOS support this feature.
917	  Otherwise the 8254 will be used for timing services.
918
919	  Choose N to continue using the legacy 8254 timer.
920
921config HPET_EMULATE_RTC
922	def_bool y
923	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
924
925# Mark as expert because too many people got it wrong.
926# The code disables itself when not needed.
927config DMI
928	default y
929	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
930	bool "Enable DMI scanning" if EXPERT
931	help
932	  Enabled scanning of DMI to identify machine quirks. Say Y
933	  here unless you have verified that your setup is not
934	  affected by entries in the DMI blacklist. Required by PNP
935	  BIOS code.
936
937config GART_IOMMU
938	bool "Old AMD GART IOMMU support"
939	select DMA_OPS
940	select IOMMU_HELPER
941	select SWIOTLB
942	depends on X86_64 && PCI && AMD_NB
943	help
944	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
945	  GART based hardware IOMMUs.
946
947	  The GART supports full DMA access for devices with 32-bit access
948	  limitations, on systems with more than 3 GB. This is usually needed
949	  for USB, sound, many IDE/SATA chipsets and some other devices.
950
951	  Newer systems typically have a modern AMD IOMMU, supported via
952	  the CONFIG_AMD_IOMMU=y config option.
953
954	  In normal configurations this driver is only active when needed:
955	  there's more than 3 GB of memory and the system contains a
956	  32-bit limited device.
957
958	  If unsure, say Y.
959
960config BOOT_VESA_SUPPORT
961	bool
962	help
963	  If true, at least one selected framebuffer driver can take advantage
964	  of VESA video modes set at an early boot stage via the vga= parameter.
965
966config MAXSMP
967	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
968	depends on X86_64 && SMP && DEBUG_KERNEL
969	select CPUMASK_OFFSTACK
970	help
971	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
972	  If unsure, say N.
973
974#
975# The maximum number of CPUs supported:
976#
977# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
978# and which can be configured interactively in the
979# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
980#
981# The ranges are different on 32-bit and 64-bit kernels, depending on
982# hardware capabilities and scalability features of the kernel.
983#
984# ( If MAXSMP is enabled we just use the highest possible value and disable
985#   interactive configuration. )
986#
987
988config NR_CPUS_RANGE_BEGIN
989	int
990	default NR_CPUS_RANGE_END if MAXSMP
991	default    1 if !SMP
992	default    2
993
994config NR_CPUS_RANGE_END
995	int
996	depends on X86_32
997	default   64 if  SMP &&  X86_BIGSMP
998	default    8 if  SMP && !X86_BIGSMP
999	default    1 if !SMP
1000
1001config NR_CPUS_RANGE_END
1002	int
1003	depends on X86_64
1004	default 8192 if  SMP && CPUMASK_OFFSTACK
1005	default  512 if  SMP && !CPUMASK_OFFSTACK
1006	default    1 if !SMP
1007
1008config NR_CPUS_DEFAULT
1009	int
1010	depends on X86_32
1011	default   32 if  X86_BIGSMP
1012	default    8 if  SMP
1013	default    1 if !SMP
1014
1015config NR_CPUS_DEFAULT
1016	int
1017	depends on X86_64
1018	default 8192 if  MAXSMP
1019	default   64 if  SMP
1020	default    1 if !SMP
1021
1022config NR_CPUS
1023	int "Maximum number of CPUs" if SMP && !MAXSMP
1024	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1025	default NR_CPUS_DEFAULT
1026	help
1027	  This allows you to specify the maximum number of CPUs which this
1028	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1029	  supported value is 8192, otherwise the maximum value is 512.  The
1030	  minimum value which makes sense is 2.
1031
1032	  This is purely to save memory: each supported CPU adds about 8KB
1033	  to the kernel image.
1034
1035config SCHED_CLUSTER
1036	bool "Cluster scheduler support"
1037	depends on SMP
1038	default y
1039	help
1040	  Cluster scheduler support improves the CPU scheduler's decision
1041	  making when dealing with machines that have clusters of CPUs.
1042	  Cluster usually means a couple of CPUs which are placed closely
1043	  by sharing mid-level caches, last-level cache tags or internal
1044	  busses.
1045
1046config SCHED_SMT
1047	def_bool y if SMP
1048
1049config SCHED_MC
1050	def_bool y
1051	prompt "Multi-core scheduler support"
1052	depends on SMP
1053	help
1054	  Multi-core scheduler support improves the CPU scheduler's decision
1055	  making when dealing with multi-core CPU chips at a cost of slightly
1056	  increased overhead in some places. If unsure say N here.
1057
1058config SCHED_MC_PRIO
1059	bool "CPU core priorities scheduler support"
1060	depends on SCHED_MC && CPU_SUP_INTEL
1061	select X86_INTEL_PSTATE
1062	select CPU_FREQ
1063	default y
1064	help
1065	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1066	  core ordering determined at manufacturing time, which allows
1067	  certain cores to reach higher turbo frequencies (when running
1068	  single threaded workloads) than others.
1069
1070	  Enabling this kernel feature teaches the scheduler about
1071	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1072	  scheduler's CPU selection logic accordingly, so that higher
1073	  overall system performance can be achieved.
1074
1075	  This feature will have no effect on CPUs without this feature.
1076
1077	  If unsure say Y here.
1078
1079config UP_LATE_INIT
1080	def_bool y
1081	depends on !SMP && X86_LOCAL_APIC
1082
1083config X86_UP_APIC
1084	bool "Local APIC support on uniprocessors" if !PCI_MSI
1085	default PCI_MSI
1086	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1087	help
1088	  A local APIC (Advanced Programmable Interrupt Controller) is an
1089	  integrated interrupt controller in the CPU. If you have a single-CPU
1090	  system which has a processor with a local APIC, you can say Y here to
1091	  enable and use it. If you say Y here even though your machine doesn't
1092	  have a local APIC, then the kernel will still run with no slowdown at
1093	  all. The local APIC supports CPU-generated self-interrupts (timer,
1094	  performance counters), and the NMI watchdog which detects hard
1095	  lockups.
1096
1097config X86_UP_IOAPIC
1098	bool "IO-APIC support on uniprocessors"
1099	depends on X86_UP_APIC
1100	help
1101	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1102	  SMP-capable replacement for PC-style interrupt controllers. Most
1103	  SMP systems and many recent uniprocessor systems have one.
1104
1105	  If you have a single-CPU system with an IO-APIC, you can say Y here
1106	  to use it. If you say Y here even though your machine doesn't have
1107	  an IO-APIC, then the kernel will still run with no slowdown at all.
1108
1109config X86_LOCAL_APIC
1110	def_bool y
1111	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1112	select IRQ_DOMAIN_HIERARCHY
1113
1114config X86_IO_APIC
1115	def_bool y
1116	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1117
1118config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1119	bool "Reroute for broken boot IRQs"
1120	depends on X86_IO_APIC
1121	help
1122	  This option enables a workaround that fixes a source of
1123	  spurious interrupts. This is recommended when threaded
1124	  interrupt handling is used on systems where the generation of
1125	  superfluous "boot interrupts" cannot be disabled.
1126
1127	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1128	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1129	  kernel does during interrupt handling). On chipsets where this
1130	  boot IRQ generation cannot be disabled, this workaround keeps
1131	  the original IRQ line masked so that only the equivalent "boot
1132	  IRQ" is delivered to the CPUs. The workaround also tells the
1133	  kernel to set up the IRQ handler on the boot IRQ line. In this
1134	  way only one interrupt is delivered to the kernel. Otherwise
1135	  the spurious second interrupt may cause the kernel to bring
1136	  down (vital) interrupt lines.
1137
1138	  Only affects "broken" chipsets. Interrupt sharing may be
1139	  increased on these systems.
1140
1141config X86_MCE
1142	bool "Machine Check / overheating reporting"
1143	select GENERIC_ALLOCATOR
1144	default y
1145	help
1146	  Machine Check support allows the processor to notify the
1147	  kernel if it detects a problem (e.g. overheating, data corruption).
1148	  The action the kernel takes depends on the severity of the problem,
1149	  ranging from warning messages to halting the machine.
1150
1151config X86_MCELOG_LEGACY
1152	bool "Support for deprecated /dev/mcelog character device"
1153	depends on X86_MCE
1154	help
1155	  Enable support for /dev/mcelog which is needed by the old mcelog
1156	  userspace logging daemon. Consider switching to the new generation
1157	  rasdaemon solution.
1158
1159config X86_MCE_INTEL
1160	def_bool y
1161	prompt "Intel MCE features"
1162	depends on X86_MCE && X86_LOCAL_APIC
1163	help
1164	  Additional support for intel specific MCE features such as
1165	  the thermal monitor.
1166
1167config X86_MCE_AMD
1168	def_bool y
1169	prompt "AMD MCE features"
1170	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1171	help
1172	  Additional support for AMD specific MCE features such as
1173	  the DRAM Error Threshold.
1174
1175config X86_ANCIENT_MCE
1176	bool "Support for old Pentium 5 / WinChip machine checks"
1177	depends on X86_32 && X86_MCE
1178	help
1179	  Include support for machine check handling on old Pentium 5 or WinChip
1180	  systems. These typically need to be enabled explicitly on the command
1181	  line.
1182
1183config X86_MCE_THRESHOLD
1184	depends on X86_MCE_AMD || X86_MCE_INTEL
1185	def_bool y
1186
1187config X86_MCE_INJECT
1188	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1189	tristate "Machine check injector support"
1190	help
1191	  Provide support for injecting machine checks for testing purposes.
1192	  If you don't know what a machine check is and you don't do kernel
1193	  QA it is safe to say n.
1194
1195source "arch/x86/events/Kconfig"
1196
1197config X86_LEGACY_VM86
1198	bool "Legacy VM86 support"
1199	depends on X86_32
1200	help
1201	  This option allows user programs to put the CPU into V8086
1202	  mode, which is an 80286-era approximation of 16-bit real mode.
1203
1204	  Some very old versions of X and/or vbetool require this option
1205	  for user mode setting.  Similarly, DOSEMU will use it if
1206	  available to accelerate real mode DOS programs.  However, any
1207	  recent version of DOSEMU, X, or vbetool should be fully
1208	  functional even without kernel VM86 support, as they will all
1209	  fall back to software emulation. Nevertheless, if you are using
1210	  a 16-bit DOS program where 16-bit performance matters, vm86
1211	  mode might be faster than emulation and you might want to
1212	  enable this option.
1213
1214	  Note that any app that works on a 64-bit kernel is unlikely to
1215	  need this option, as 64-bit kernels don't, and can't, support
1216	  V8086 mode. This option is also unrelated to 16-bit protected
1217	  mode and is not needed to run most 16-bit programs under Wine.
1218
1219	  Enabling this option increases the complexity of the kernel
1220	  and slows down exception handling a tiny bit.
1221
1222	  If unsure, say N here.
1223
1224config VM86
1225	bool
1226	default X86_LEGACY_VM86
1227
1228config X86_16BIT
1229	bool "Enable support for 16-bit segments" if EXPERT
1230	default y
1231	depends on MODIFY_LDT_SYSCALL
1232	help
1233	  This option is required by programs like Wine to run 16-bit
1234	  protected mode legacy code on x86 processors.  Disabling
1235	  this option saves about 300 bytes on i386, or around 6K text
1236	  plus 16K runtime memory on x86-64,
1237
1238config X86_ESPFIX32
1239	def_bool y
1240	depends on X86_16BIT && X86_32
1241
1242config X86_ESPFIX64
1243	def_bool y
1244	depends on X86_16BIT && X86_64
1245
1246config X86_VSYSCALL_EMULATION
1247	bool "Enable vsyscall emulation" if EXPERT
1248	default y
1249	depends on X86_64
1250	help
1251	  This enables emulation of the legacy vsyscall page.  Disabling
1252	  it is roughly equivalent to booting with vsyscall=none, except
1253	  that it will also disable the helpful warning if a program
1254	  tries to use a vsyscall.  With this option set to N, offending
1255	  programs will just segfault, citing addresses of the form
1256	  0xffffffffff600?00.
1257
1258	  This option is required by many programs built before 2013, and
1259	  care should be used even with newer programs if set to N.
1260
1261	  Disabling this option saves about 7K of kernel size and
1262	  possibly 4K of additional runtime pagetable memory.
1263
1264config X86_IOPL_IOPERM
1265	bool "IOPERM and IOPL Emulation"
1266	default y
1267	help
1268	  This enables the ioperm() and iopl() syscalls which are necessary
1269	  for legacy applications.
1270
1271	  Legacy IOPL support is an overbroad mechanism which allows user
1272	  space aside of accessing all 65536 I/O ports also to disable
1273	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1274	  capabilities and permission from potentially active security
1275	  modules.
1276
1277	  The emulation restricts the functionality of the syscall to
1278	  only allowing the full range I/O port access, but prevents the
1279	  ability to disable interrupts from user space which would be
1280	  granted if the hardware IOPL mechanism would be used.
1281
1282config TOSHIBA
1283	tristate "Toshiba Laptop support"
1284	depends on X86_32
1285	help
1286	  This adds a driver to safely access the System Management Mode of
1287	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1288	  not work on models with a Phoenix BIOS. The System Management Mode
1289	  is used to set the BIOS and power saving options on Toshiba portables.
1290
1291	  For information on utilities to make use of this driver see the
1292	  Toshiba Linux utilities web site at:
1293	  <http://www.buzzard.org.uk/toshiba/>.
1294
1295	  Say Y if you intend to run this kernel on a Toshiba portable.
1296	  Say N otherwise.
1297
1298config X86_REBOOTFIXUPS
1299	bool "Enable X86 board specific fixups for reboot"
1300	depends on X86_32
1301	help
1302	  This enables chipset and/or board specific fixups to be done
1303	  in order to get reboot to work correctly. This is only needed on
1304	  some combinations of hardware and BIOS. The symptom, for which
1305	  this config is intended, is when reboot ends with a stalled/hung
1306	  system.
1307
1308	  Currently, the only fixup is for the Geode machines using
1309	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1310
1311	  Say Y if you want to enable the fixup. Currently, it's safe to
1312	  enable this option even if you don't need it.
1313	  Say N otherwise.
1314
1315config MICROCODE
1316	bool "CPU microcode loading support"
1317	default y
1318	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1319	help
1320	  If you say Y here, you will be able to update the microcode on
1321	  Intel and AMD processors. The Intel support is for the IA32 family,
1322	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1323	  AMD support is for families 0x10 and later. You will obviously need
1324	  the actual microcode binary data itself which is not shipped with
1325	  the Linux kernel.
1326
1327	  The preferred method to load microcode from a detached initrd is described
1328	  in Documentation/x86/microcode.rst. For that you need to enable
1329	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1330	  initrd for microcode blobs.
1331
1332	  In addition, you can build the microcode into the kernel. For that you
1333	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1334	  config option.
1335
1336config MICROCODE_INTEL
1337	bool "Intel microcode loading support"
1338	depends on CPU_SUP_INTEL && MICROCODE
1339	default MICROCODE
1340	help
1341	  This options enables microcode patch loading support for Intel
1342	  processors.
1343
1344	  For the current Intel microcode data package go to
1345	  <https://downloadcenter.intel.com> and search for
1346	  'Linux Processor Microcode Data File'.
1347
1348config MICROCODE_AMD
1349	bool "AMD microcode loading support"
1350	depends on CPU_SUP_AMD && MICROCODE
1351	help
1352	  If you select this option, microcode patch loading support for AMD
1353	  processors will be enabled.
1354
1355config MICROCODE_LATE_LOADING
1356	bool "Late microcode loading (DANGEROUS)"
1357	default n
1358	depends on MICROCODE
1359	help
1360	  Loading microcode late, when the system is up and executing instructions
1361	  is a tricky business and should be avoided if possible. Just the sequence
1362	  of synchronizing all cores and SMT threads is one fragile dance which does
1363	  not guarantee that cores might not softlock after the loading. Therefore,
1364	  use this at your own risk. Late loading taints the kernel too.
1365
1366config X86_MSR
1367	tristate "/dev/cpu/*/msr - Model-specific register support"
1368	help
1369	  This device gives privileged processes access to the x86
1370	  Model-Specific Registers (MSRs).  It is a character device with
1371	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1372	  MSR accesses are directed to a specific CPU on multi-processor
1373	  systems.
1374
1375config X86_CPUID
1376	tristate "/dev/cpu/*/cpuid - CPU information support"
1377	help
1378	  This device gives processes access to the x86 CPUID instruction to
1379	  be executed on a specific processor.  It is a character device
1380	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1381	  /dev/cpu/31/cpuid.
1382
1383choice
1384	prompt "High Memory Support"
1385	default HIGHMEM4G
1386	depends on X86_32
1387
1388config NOHIGHMEM
1389	bool "off"
1390	help
1391	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1392	  However, the address space of 32-bit x86 processors is only 4
1393	  Gigabytes large. That means that, if you have a large amount of
1394	  physical memory, not all of it can be "permanently mapped" by the
1395	  kernel. The physical memory that's not permanently mapped is called
1396	  "high memory".
1397
1398	  If you are compiling a kernel which will never run on a machine with
1399	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1400	  choice and suitable for most users). This will result in a "3GB/1GB"
1401	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1402	  space and the remaining part of the 4GB virtual memory space is used
1403	  by the kernel to permanently map as much physical memory as
1404	  possible.
1405
1406	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1407	  answer "4GB" here.
1408
1409	  If more than 4 Gigabytes is used then answer "64GB" here. This
1410	  selection turns Intel PAE (Physical Address Extension) mode on.
1411	  PAE implements 3-level paging on IA32 processors. PAE is fully
1412	  supported by Linux, PAE mode is implemented on all recent Intel
1413	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1414	  then the kernel will not boot on CPUs that don't support PAE!
1415
1416	  The actual amount of total physical memory will either be
1417	  auto detected or can be forced by using a kernel command line option
1418	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1419	  your boot loader (lilo or loadlin) about how to pass options to the
1420	  kernel at boot time.)
1421
1422	  If unsure, say "off".
1423
1424config HIGHMEM4G
1425	bool "4GB"
1426	help
1427	  Select this if you have a 32-bit processor and between 1 and 4
1428	  gigabytes of physical RAM.
1429
1430config HIGHMEM64G
1431	bool "64GB"
1432	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1433	select X86_PAE
1434	help
1435	  Select this if you have a 32-bit processor and more than 4
1436	  gigabytes of physical RAM.
1437
1438endchoice
1439
1440choice
1441	prompt "Memory split" if EXPERT
1442	default VMSPLIT_3G
1443	depends on X86_32
1444	help
1445	  Select the desired split between kernel and user memory.
1446
1447	  If the address range available to the kernel is less than the
1448	  physical memory installed, the remaining memory will be available
1449	  as "high memory". Accessing high memory is a little more costly
1450	  than low memory, as it needs to be mapped into the kernel first.
1451	  Note that increasing the kernel address space limits the range
1452	  available to user programs, making the address space there
1453	  tighter.  Selecting anything other than the default 3G/1G split
1454	  will also likely make your kernel incompatible with binary-only
1455	  kernel modules.
1456
1457	  If you are not absolutely sure what you are doing, leave this
1458	  option alone!
1459
1460	config VMSPLIT_3G
1461		bool "3G/1G user/kernel split"
1462	config VMSPLIT_3G_OPT
1463		depends on !X86_PAE
1464		bool "3G/1G user/kernel split (for full 1G low memory)"
1465	config VMSPLIT_2G
1466		bool "2G/2G user/kernel split"
1467	config VMSPLIT_2G_OPT
1468		depends on !X86_PAE
1469		bool "2G/2G user/kernel split (for full 2G low memory)"
1470	config VMSPLIT_1G
1471		bool "1G/3G user/kernel split"
1472endchoice
1473
1474config PAGE_OFFSET
1475	hex
1476	default 0xB0000000 if VMSPLIT_3G_OPT
1477	default 0x80000000 if VMSPLIT_2G
1478	default 0x78000000 if VMSPLIT_2G_OPT
1479	default 0x40000000 if VMSPLIT_1G
1480	default 0xC0000000
1481	depends on X86_32
1482
1483config HIGHMEM
1484	def_bool y
1485	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1486
1487config X86_PAE
1488	bool "PAE (Physical Address Extension) Support"
1489	depends on X86_32 && !HIGHMEM4G
1490	select PHYS_ADDR_T_64BIT
1491	select SWIOTLB
1492	help
1493	  PAE is required for NX support, and furthermore enables
1494	  larger swapspace support for non-overcommit purposes. It
1495	  has the cost of more pagetable lookup overhead, and also
1496	  consumes more pagetable space per process.
1497
1498config X86_5LEVEL
1499	bool "Enable 5-level page tables support"
1500	default y
1501	select DYNAMIC_MEMORY_LAYOUT
1502	select SPARSEMEM_VMEMMAP
1503	depends on X86_64
1504	help
1505	  5-level paging enables access to larger address space:
1506	  up to 128 PiB of virtual address space and 4 PiB of
1507	  physical address space.
1508
1509	  It will be supported by future Intel CPUs.
1510
1511	  A kernel with the option enabled can be booted on machines that
1512	  support 4- or 5-level paging.
1513
1514	  See Documentation/x86/x86_64/5level-paging.rst for more
1515	  information.
1516
1517	  Say N if unsure.
1518
1519config X86_DIRECT_GBPAGES
1520	def_bool y
1521	depends on X86_64
1522	help
1523	  Certain kernel features effectively disable kernel
1524	  linear 1 GB mappings (even if the CPU otherwise
1525	  supports them), so don't confuse the user by printing
1526	  that we have them enabled.
1527
1528config X86_CPA_STATISTICS
1529	bool "Enable statistic for Change Page Attribute"
1530	depends on DEBUG_FS
1531	help
1532	  Expose statistics about the Change Page Attribute mechanism, which
1533	  helps to determine the effectiveness of preserving large and huge
1534	  page mappings when mapping protections are changed.
1535
1536config X86_MEM_ENCRYPT
1537	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1538	select DYNAMIC_PHYSICAL_MASK
1539	def_bool n
1540
1541config AMD_MEM_ENCRYPT
1542	bool "AMD Secure Memory Encryption (SME) support"
1543	depends on X86_64 && CPU_SUP_AMD
1544	select DMA_COHERENT_POOL
1545	select ARCH_USE_MEMREMAP_PROT
1546	select INSTRUCTION_DECODER
1547	select ARCH_HAS_CC_PLATFORM
1548	select X86_MEM_ENCRYPT
1549	help
1550	  Say yes to enable support for the encryption of system memory.
1551	  This requires an AMD processor that supports Secure Memory
1552	  Encryption (SME).
1553
1554config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1555	bool "Activate AMD Secure Memory Encryption (SME) by default"
1556	depends on AMD_MEM_ENCRYPT
1557	help
1558	  Say yes to have system memory encrypted by default if running on
1559	  an AMD processor that supports Secure Memory Encryption (SME).
1560
1561	  If set to Y, then the encryption of system memory can be
1562	  deactivated with the mem_encrypt=off command line option.
1563
1564	  If set to N, then the encryption of system memory can be
1565	  activated with the mem_encrypt=on command line option.
1566
1567# Common NUMA Features
1568config NUMA
1569	bool "NUMA Memory Allocation and Scheduler Support"
1570	depends on SMP
1571	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1572	default y if X86_BIGSMP
1573	select USE_PERCPU_NUMA_NODE_ID
1574	help
1575	  Enable NUMA (Non-Uniform Memory Access) support.
1576
1577	  The kernel will try to allocate memory used by a CPU on the
1578	  local memory controller of the CPU and add some more
1579	  NUMA awareness to the kernel.
1580
1581	  For 64-bit this is recommended if the system is Intel Core i7
1582	  (or later), AMD Opteron, or EM64T NUMA.
1583
1584	  For 32-bit this is only needed if you boot a 32-bit
1585	  kernel on a 64-bit NUMA platform.
1586
1587	  Otherwise, you should say N.
1588
1589config AMD_NUMA
1590	def_bool y
1591	prompt "Old style AMD Opteron NUMA detection"
1592	depends on X86_64 && NUMA && PCI
1593	help
1594	  Enable AMD NUMA node topology detection.  You should say Y here if
1595	  you have a multi processor AMD system. This uses an old method to
1596	  read the NUMA configuration directly from the builtin Northbridge
1597	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1598	  which also takes priority if both are compiled in.
1599
1600config X86_64_ACPI_NUMA
1601	def_bool y
1602	prompt "ACPI NUMA detection"
1603	depends on X86_64 && NUMA && ACPI && PCI
1604	select ACPI_NUMA
1605	help
1606	  Enable ACPI SRAT based node topology detection.
1607
1608config NUMA_EMU
1609	bool "NUMA emulation"
1610	depends on NUMA
1611	help
1612	  Enable NUMA emulation. A flat machine will be split
1613	  into virtual nodes when booted with "numa=fake=N", where N is the
1614	  number of nodes. This is only useful for debugging.
1615
1616config NODES_SHIFT
1617	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1618	range 1 10
1619	default "10" if MAXSMP
1620	default "6" if X86_64
1621	default "3"
1622	depends on NUMA
1623	help
1624	  Specify the maximum number of NUMA Nodes available on the target
1625	  system.  Increases memory reserved to accommodate various tables.
1626
1627config ARCH_FLATMEM_ENABLE
1628	def_bool y
1629	depends on X86_32 && !NUMA
1630
1631config ARCH_SPARSEMEM_ENABLE
1632	def_bool y
1633	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1634	select SPARSEMEM_STATIC if X86_32
1635	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1636
1637config ARCH_SPARSEMEM_DEFAULT
1638	def_bool X86_64 || (NUMA && X86_32)
1639
1640config ARCH_SELECT_MEMORY_MODEL
1641	def_bool y
1642	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1643
1644config ARCH_MEMORY_PROBE
1645	bool "Enable sysfs memory/probe interface"
1646	depends on MEMORY_HOTPLUG
1647	help
1648	  This option enables a sysfs memory/probe interface for testing.
1649	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1650	  If you are unsure how to answer this question, answer N.
1651
1652config ARCH_PROC_KCORE_TEXT
1653	def_bool y
1654	depends on X86_64 && PROC_KCORE
1655
1656config ILLEGAL_POINTER_VALUE
1657	hex
1658	default 0 if X86_32
1659	default 0xdead000000000000 if X86_64
1660
1661config X86_PMEM_LEGACY_DEVICE
1662	bool
1663
1664config X86_PMEM_LEGACY
1665	tristate "Support non-standard NVDIMMs and ADR protected memory"
1666	depends on PHYS_ADDR_T_64BIT
1667	depends on BLK_DEV
1668	select X86_PMEM_LEGACY_DEVICE
1669	select NUMA_KEEP_MEMINFO if NUMA
1670	select LIBNVDIMM
1671	help
1672	  Treat memory marked using the non-standard e820 type of 12 as used
1673	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1674	  The kernel will offer these regions to the 'pmem' driver so
1675	  they can be used for persistent storage.
1676
1677	  Say Y if unsure.
1678
1679config HIGHPTE
1680	bool "Allocate 3rd-level pagetables from highmem"
1681	depends on HIGHMEM
1682	help
1683	  The VM uses one page table entry for each page of physical memory.
1684	  For systems with a lot of RAM, this can be wasteful of precious
1685	  low memory.  Setting this option will put user-space page table
1686	  entries in high memory.
1687
1688config X86_CHECK_BIOS_CORRUPTION
1689	bool "Check for low memory corruption"
1690	help
1691	  Periodically check for memory corruption in low memory, which
1692	  is suspected to be caused by BIOS.  Even when enabled in the
1693	  configuration, it is disabled at runtime.  Enable it by
1694	  setting "memory_corruption_check=1" on the kernel command
1695	  line.  By default it scans the low 64k of memory every 60
1696	  seconds; see the memory_corruption_check_size and
1697	  memory_corruption_check_period parameters in
1698	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1699
1700	  When enabled with the default parameters, this option has
1701	  almost no overhead, as it reserves a relatively small amount
1702	  of memory and scans it infrequently.  It both detects corruption
1703	  and prevents it from affecting the running system.
1704
1705	  It is, however, intended as a diagnostic tool; if repeatable
1706	  BIOS-originated corruption always affects the same memory,
1707	  you can use memmap= to prevent the kernel from using that
1708	  memory.
1709
1710config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1711	bool "Set the default setting of memory_corruption_check"
1712	depends on X86_CHECK_BIOS_CORRUPTION
1713	default y
1714	help
1715	  Set whether the default state of memory_corruption_check is
1716	  on or off.
1717
1718config MATH_EMULATION
1719	bool
1720	depends on MODIFY_LDT_SYSCALL
1721	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1722	help
1723	  Linux can emulate a math coprocessor (used for floating point
1724	  operations) if you don't have one. 486DX and Pentium processors have
1725	  a math coprocessor built in, 486SX and 386 do not, unless you added
1726	  a 487DX or 387, respectively. (The messages during boot time can
1727	  give you some hints here ["man dmesg"].) Everyone needs either a
1728	  coprocessor or this emulation.
1729
1730	  If you don't have a math coprocessor, you need to say Y here; if you
1731	  say Y here even though you have a coprocessor, the coprocessor will
1732	  be used nevertheless. (This behavior can be changed with the kernel
1733	  command line option "no387", which comes handy if your coprocessor
1734	  is broken. Try "man bootparam" or see the documentation of your boot
1735	  loader (lilo or loadlin) about how to pass options to the kernel at
1736	  boot time.) This means that it is a good idea to say Y here if you
1737	  intend to use this kernel on different machines.
1738
1739	  More information about the internals of the Linux math coprocessor
1740	  emulation can be found in <file:arch/x86/math-emu/README>.
1741
1742	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1743	  kernel, it won't hurt.
1744
1745config MTRR
1746	def_bool y
1747	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1748	help
1749	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1750	  the Memory Type Range Registers (MTRRs) may be used to control
1751	  processor access to memory ranges. This is most useful if you have
1752	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1753	  allows bus write transfers to be combined into a larger transfer
1754	  before bursting over the PCI/AGP bus. This can increase performance
1755	  of image write operations 2.5 times or more. Saying Y here creates a
1756	  /proc/mtrr file which may be used to manipulate your processor's
1757	  MTRRs. Typically the X server should use this.
1758
1759	  This code has a reasonably generic interface so that similar
1760	  control registers on other processors can be easily supported
1761	  as well:
1762
1763	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1764	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1765	  these, the ARRs are used to emulate the MTRRs.
1766	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1767	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1768	  write-combining. All of these processors are supported by this code
1769	  and it makes sense to say Y here if you have one of them.
1770
1771	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1772	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1773	  can lead to all sorts of problems, so it's good to say Y here.
1774
1775	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1776	  just add about 9 KB to your kernel.
1777
1778	  See <file:Documentation/x86/mtrr.rst> for more information.
1779
1780config MTRR_SANITIZER
1781	def_bool y
1782	prompt "MTRR cleanup support"
1783	depends on MTRR
1784	help
1785	  Convert MTRR layout from continuous to discrete, so X drivers can
1786	  add writeback entries.
1787
1788	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1789	  The largest mtrr entry size for a continuous block can be set with
1790	  mtrr_chunk_size.
1791
1792	  If unsure, say Y.
1793
1794config MTRR_SANITIZER_ENABLE_DEFAULT
1795	int "MTRR cleanup enable value (0-1)"
1796	range 0 1
1797	default "0"
1798	depends on MTRR_SANITIZER
1799	help
1800	  Enable mtrr cleanup default value
1801
1802config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1803	int "MTRR cleanup spare reg num (0-7)"
1804	range 0 7
1805	default "1"
1806	depends on MTRR_SANITIZER
1807	help
1808	  mtrr cleanup spare entries default, it can be changed via
1809	  mtrr_spare_reg_nr=N on the kernel command line.
1810
1811config X86_PAT
1812	def_bool y
1813	prompt "x86 PAT support" if EXPERT
1814	depends on MTRR
1815	help
1816	  Use PAT attributes to setup page level cache control.
1817
1818	  PATs are the modern equivalents of MTRRs and are much more
1819	  flexible than MTRRs.
1820
1821	  Say N here if you see bootup problems (boot crash, boot hang,
1822	  spontaneous reboots) or a non-working video driver.
1823
1824	  If unsure, say Y.
1825
1826config ARCH_USES_PG_UNCACHED
1827	def_bool y
1828	depends on X86_PAT
1829
1830config X86_UMIP
1831	def_bool y
1832	prompt "User Mode Instruction Prevention" if EXPERT
1833	help
1834	  User Mode Instruction Prevention (UMIP) is a security feature in
1835	  some x86 processors. If enabled, a general protection fault is
1836	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1837	  executed in user mode. These instructions unnecessarily expose
1838	  information about the hardware state.
1839
1840	  The vast majority of applications do not use these instructions.
1841	  For the very few that do, software emulation is provided in
1842	  specific cases in protected and virtual-8086 modes. Emulated
1843	  results are dummy.
1844
1845config CC_HAS_IBT
1846	# GCC >= 9 and binutils >= 2.29
1847	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1848	# Clang/LLVM >= 14
1849	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1850	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1851	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1852		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1853		  $(as-instr,endbr64)
1854
1855config X86_KERNEL_IBT
1856	prompt "Indirect Branch Tracking"
1857	def_bool y
1858	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1859	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1860	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1861	select OBJTOOL
1862	help
1863	  Build the kernel with support for Indirect Branch Tracking, a
1864	  hardware support course-grain forward-edge Control Flow Integrity
1865	  protection. It enforces that all indirect calls must land on
1866	  an ENDBR instruction, as such, the compiler will instrument the
1867	  code with them to make this happen.
1868
1869	  In addition to building the kernel with IBT, seal all functions that
1870	  are not indirect call targets, avoiding them ever becoming one.
1871
1872	  This requires LTO like objtool runs and will slow down the build. It
1873	  does significantly reduce the number of ENDBR instructions in the
1874	  kernel image.
1875
1876config X86_INTEL_MEMORY_PROTECTION_KEYS
1877	prompt "Memory Protection Keys"
1878	def_bool y
1879	# Note: only available in 64-bit mode
1880	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1881	select ARCH_USES_HIGH_VMA_FLAGS
1882	select ARCH_HAS_PKEYS
1883	help
1884	  Memory Protection Keys provides a mechanism for enforcing
1885	  page-based protections, but without requiring modification of the
1886	  page tables when an application changes protection domains.
1887
1888	  For details, see Documentation/core-api/protection-keys.rst
1889
1890	  If unsure, say y.
1891
1892choice
1893	prompt "TSX enable mode"
1894	depends on CPU_SUP_INTEL
1895	default X86_INTEL_TSX_MODE_OFF
1896	help
1897	  Intel's TSX (Transactional Synchronization Extensions) feature
1898	  allows to optimize locking protocols through lock elision which
1899	  can lead to a noticeable performance boost.
1900
1901	  On the other hand it has been shown that TSX can be exploited
1902	  to form side channel attacks (e.g. TAA) and chances are there
1903	  will be more of those attacks discovered in the future.
1904
1905	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1906	  might override this decision by tsx=on the command line parameter.
1907	  Even with TSX enabled, the kernel will attempt to enable the best
1908	  possible TAA mitigation setting depending on the microcode available
1909	  for the particular machine.
1910
1911	  This option allows to set the default tsx mode between tsx=on, =off
1912	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1913	  details.
1914
1915	  Say off if not sure, auto if TSX is in use but it should be used on safe
1916	  platforms or on if TSX is in use and the security aspect of tsx is not
1917	  relevant.
1918
1919config X86_INTEL_TSX_MODE_OFF
1920	bool "off"
1921	help
1922	  TSX is disabled if possible - equals to tsx=off command line parameter.
1923
1924config X86_INTEL_TSX_MODE_ON
1925	bool "on"
1926	help
1927	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1928	  line parameter.
1929
1930config X86_INTEL_TSX_MODE_AUTO
1931	bool "auto"
1932	help
1933	  TSX is enabled on TSX capable HW that is believed to be safe against
1934	  side channel attacks- equals the tsx=auto command line parameter.
1935endchoice
1936
1937config X86_SGX
1938	bool "Software Guard eXtensions (SGX)"
1939	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1940	depends on CRYPTO=y
1941	depends on CRYPTO_SHA256=y
1942	select SRCU
1943	select MMU_NOTIFIER
1944	select NUMA_KEEP_MEMINFO if NUMA
1945	select XARRAY_MULTI
1946	help
1947	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1948	  that can be used by applications to set aside private regions of code
1949	  and data, referred to as enclaves. An enclave's private memory can
1950	  only be accessed by code running within the enclave. Accesses from
1951	  outside the enclave, including other enclaves, are disallowed by
1952	  hardware.
1953
1954	  If unsure, say N.
1955
1956config EFI
1957	bool "EFI runtime service support"
1958	depends on ACPI
1959	select UCS2_STRING
1960	select EFI_RUNTIME_WRAPPERS
1961	select ARCH_USE_MEMREMAP_PROT
1962	help
1963	  This enables the kernel to use EFI runtime services that are
1964	  available (such as the EFI variable services).
1965
1966	  This option is only useful on systems that have EFI firmware.
1967	  In addition, you should use the latest ELILO loader available
1968	  at <http://elilo.sourceforge.net> in order to take advantage
1969	  of EFI runtime services. However, even with this option, the
1970	  resultant kernel should continue to boot on existing non-EFI
1971	  platforms.
1972
1973config EFI_STUB
1974	bool "EFI stub support"
1975	depends on EFI
1976	select RELOCATABLE
1977	help
1978	  This kernel feature allows a bzImage to be loaded directly
1979	  by EFI firmware without the use of a bootloader.
1980
1981	  See Documentation/admin-guide/efi-stub.rst for more information.
1982
1983config EFI_HANDOVER_PROTOCOL
1984	bool "EFI handover protocol (DEPRECATED)"
1985	depends on EFI_STUB
1986	default y
1987	help
1988	  Select this in order to include support for the deprecated EFI
1989	  handover protocol, which defines alternative entry points into the
1990	  EFI stub.  This is a practice that has no basis in the UEFI
1991	  specification, and requires a priori knowledge on the part of the
1992	  bootloader about Linux/x86 specific ways of passing the command line
1993	  and initrd, and where in memory those assets may be loaded.
1994
1995	  If in doubt, say Y. Even though the corresponding support is not
1996	  present in upstream GRUB or other bootloaders, most distros build
1997	  GRUB with numerous downstream patches applied, and may rely on the
1998	  handover protocol as as result.
1999
2000config EFI_MIXED
2001	bool "EFI mixed-mode support"
2002	depends on EFI_STUB && X86_64
2003	help
2004	  Enabling this feature allows a 64-bit kernel to be booted
2005	  on a 32-bit firmware, provided that your CPU supports 64-bit
2006	  mode.
2007
2008	  Note that it is not possible to boot a mixed-mode enabled
2009	  kernel via the EFI boot stub - a bootloader that supports
2010	  the EFI handover protocol must be used.
2011
2012	  If unsure, say N.
2013
2014config EFI_FAKE_MEMMAP
2015	bool "Enable EFI fake memory map"
2016	depends on EFI
2017	help
2018	  Saying Y here will enable "efi_fake_mem" boot option.  By specifying
2019	  this parameter, you can add arbitrary attribute to specific memory
2020	  range by updating original (firmware provided) EFI memmap.  This is
2021	  useful for debugging of EFI memmap related feature, e.g., Address
2022	  Range Mirroring feature.
2023
2024config EFI_MAX_FAKE_MEM
2025	int "maximum allowable number of ranges in efi_fake_mem boot option"
2026	depends on EFI_FAKE_MEMMAP
2027	range 1 128
2028	default 8
2029	help
2030	  Maximum allowable number of ranges in efi_fake_mem boot option.
2031	  Ranges can be set up to this value using comma-separated list.
2032	  The default value is 8.
2033
2034config EFI_RUNTIME_MAP
2035	bool "Export EFI runtime maps to sysfs" if EXPERT
2036	depends on EFI
2037	default KEXEC_CORE
2038	help
2039	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2040	  That memory map is required by the 2nd kernel to set up EFI virtual
2041	  mappings after kexec, but can also be used for debugging purposes.
2042
2043	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2044
2045source "kernel/Kconfig.hz"
2046
2047config KEXEC
2048	bool "kexec system call"
2049	select KEXEC_CORE
2050	help
2051	  kexec is a system call that implements the ability to shutdown your
2052	  current kernel, and to start another kernel.  It is like a reboot
2053	  but it is independent of the system firmware.   And like a reboot
2054	  you can start any kernel with it, not just Linux.
2055
2056	  The name comes from the similarity to the exec system call.
2057
2058	  It is an ongoing process to be certain the hardware in a machine
2059	  is properly shutdown, so do not be surprised if this code does not
2060	  initially work for you.  As of this writing the exact hardware
2061	  interface is strongly in flux, so no good recommendation can be
2062	  made.
2063
2064config KEXEC_FILE
2065	bool "kexec file based system call"
2066	select KEXEC_CORE
2067	select HAVE_IMA_KEXEC if IMA
2068	depends on X86_64
2069	depends on CRYPTO=y
2070	depends on CRYPTO_SHA256=y
2071	help
2072	  This is new version of kexec system call. This system call is
2073	  file based and takes file descriptors as system call argument
2074	  for kernel and initramfs as opposed to list of segments as
2075	  accepted by previous system call.
2076
2077config ARCH_HAS_KEXEC_PURGATORY
2078	def_bool KEXEC_FILE
2079
2080config KEXEC_SIG
2081	bool "Verify kernel signature during kexec_file_load() syscall"
2082	depends on KEXEC_FILE
2083	help
2084
2085	  This option makes the kexec_file_load() syscall check for a valid
2086	  signature of the kernel image.  The image can still be loaded without
2087	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2088	  there's a signature that we can check, then it must be valid.
2089
2090	  In addition to this option, you need to enable signature
2091	  verification for the corresponding kernel image type being
2092	  loaded in order for this to work.
2093
2094config KEXEC_SIG_FORCE
2095	bool "Require a valid signature in kexec_file_load() syscall"
2096	depends on KEXEC_SIG
2097	help
2098	  This option makes kernel signature verification mandatory for
2099	  the kexec_file_load() syscall.
2100
2101config KEXEC_BZIMAGE_VERIFY_SIG
2102	bool "Enable bzImage signature verification support"
2103	depends on KEXEC_SIG
2104	depends on SIGNED_PE_FILE_VERIFICATION
2105	select SYSTEM_TRUSTED_KEYRING
2106	help
2107	  Enable bzImage signature verification support.
2108
2109config CRASH_DUMP
2110	bool "kernel crash dumps"
2111	depends on X86_64 || (X86_32 && HIGHMEM)
2112	help
2113	  Generate crash dump after being started by kexec.
2114	  This should be normally only set in special crash dump kernels
2115	  which are loaded in the main kernel with kexec-tools into
2116	  a specially reserved region and then later executed after
2117	  a crash by kdump/kexec. The crash dump kernel must be compiled
2118	  to a memory address not used by the main kernel or BIOS using
2119	  PHYSICAL_START, or it must be built as a relocatable image
2120	  (CONFIG_RELOCATABLE=y).
2121	  For more details see Documentation/admin-guide/kdump/kdump.rst
2122
2123config KEXEC_JUMP
2124	bool "kexec jump"
2125	depends on KEXEC && HIBERNATION
2126	help
2127	  Jump between original kernel and kexeced kernel and invoke
2128	  code in physical address mode via KEXEC
2129
2130config PHYSICAL_START
2131	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2132	default "0x1000000"
2133	help
2134	  This gives the physical address where the kernel is loaded.
2135
2136	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2137	  bzImage will decompress itself to above physical address and
2138	  run from there. Otherwise, bzImage will run from the address where
2139	  it has been loaded by the boot loader and will ignore above physical
2140	  address.
2141
2142	  In normal kdump cases one does not have to set/change this option
2143	  as now bzImage can be compiled as a completely relocatable image
2144	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2145	  address. This option is mainly useful for the folks who don't want
2146	  to use a bzImage for capturing the crash dump and want to use a
2147	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2148	  to be specifically compiled to run from a specific memory area
2149	  (normally a reserved region) and this option comes handy.
2150
2151	  So if you are using bzImage for capturing the crash dump,
2152	  leave the value here unchanged to 0x1000000 and set
2153	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2154	  for capturing the crash dump change this value to start of
2155	  the reserved region.  In other words, it can be set based on
2156	  the "X" value as specified in the "crashkernel=YM@XM"
2157	  command line boot parameter passed to the panic-ed
2158	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2159	  for more details about crash dumps.
2160
2161	  Usage of bzImage for capturing the crash dump is recommended as
2162	  one does not have to build two kernels. Same kernel can be used
2163	  as production kernel and capture kernel. Above option should have
2164	  gone away after relocatable bzImage support is introduced. But it
2165	  is present because there are users out there who continue to use
2166	  vmlinux for dump capture. This option should go away down the
2167	  line.
2168
2169	  Don't change this unless you know what you are doing.
2170
2171config RELOCATABLE
2172	bool "Build a relocatable kernel"
2173	default y
2174	help
2175	  This builds a kernel image that retains relocation information
2176	  so it can be loaded someplace besides the default 1MB.
2177	  The relocations tend to make the kernel binary about 10% larger,
2178	  but are discarded at runtime.
2179
2180	  One use is for the kexec on panic case where the recovery kernel
2181	  must live at a different physical address than the primary
2182	  kernel.
2183
2184	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2185	  it has been loaded at and the compile time physical address
2186	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2187
2188config RANDOMIZE_BASE
2189	bool "Randomize the address of the kernel image (KASLR)"
2190	depends on RELOCATABLE
2191	default y
2192	help
2193	  In support of Kernel Address Space Layout Randomization (KASLR),
2194	  this randomizes the physical address at which the kernel image
2195	  is decompressed and the virtual address where the kernel
2196	  image is mapped, as a security feature that deters exploit
2197	  attempts relying on knowledge of the location of kernel
2198	  code internals.
2199
2200	  On 64-bit, the kernel physical and virtual addresses are
2201	  randomized separately. The physical address will be anywhere
2202	  between 16MB and the top of physical memory (up to 64TB). The
2203	  virtual address will be randomized from 16MB up to 1GB (9 bits
2204	  of entropy). Note that this also reduces the memory space
2205	  available to kernel modules from 1.5GB to 1GB.
2206
2207	  On 32-bit, the kernel physical and virtual addresses are
2208	  randomized together. They will be randomized from 16MB up to
2209	  512MB (8 bits of entropy).
2210
2211	  Entropy is generated using the RDRAND instruction if it is
2212	  supported. If RDTSC is supported, its value is mixed into
2213	  the entropy pool as well. If neither RDRAND nor RDTSC are
2214	  supported, then entropy is read from the i8254 timer. The
2215	  usable entropy is limited by the kernel being built using
2216	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2217	  minimum of 2MB. As a result, only 10 bits of entropy are
2218	  theoretically possible, but the implementations are further
2219	  limited due to memory layouts.
2220
2221	  If unsure, say Y.
2222
2223# Relocation on x86 needs some additional build support
2224config X86_NEED_RELOCS
2225	def_bool y
2226	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2227
2228config PHYSICAL_ALIGN
2229	hex "Alignment value to which kernel should be aligned"
2230	default "0x200000"
2231	range 0x2000 0x1000000 if X86_32
2232	range 0x200000 0x1000000 if X86_64
2233	help
2234	  This value puts the alignment restrictions on physical address
2235	  where kernel is loaded and run from. Kernel is compiled for an
2236	  address which meets above alignment restriction.
2237
2238	  If bootloader loads the kernel at a non-aligned address and
2239	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2240	  address aligned to above value and run from there.
2241
2242	  If bootloader loads the kernel at a non-aligned address and
2243	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2244	  load address and decompress itself to the address it has been
2245	  compiled for and run from there. The address for which kernel is
2246	  compiled already meets above alignment restrictions. Hence the
2247	  end result is that kernel runs from a physical address meeting
2248	  above alignment restrictions.
2249
2250	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2251	  this value must be a multiple of 0x200000.
2252
2253	  Don't change this unless you know what you are doing.
2254
2255config DYNAMIC_MEMORY_LAYOUT
2256	bool
2257	help
2258	  This option makes base addresses of vmalloc and vmemmap as well as
2259	  __PAGE_OFFSET movable during boot.
2260
2261config RANDOMIZE_MEMORY
2262	bool "Randomize the kernel memory sections"
2263	depends on X86_64
2264	depends on RANDOMIZE_BASE
2265	select DYNAMIC_MEMORY_LAYOUT
2266	default RANDOMIZE_BASE
2267	help
2268	  Randomizes the base virtual address of kernel memory sections
2269	  (physical memory mapping, vmalloc & vmemmap). This security feature
2270	  makes exploits relying on predictable memory locations less reliable.
2271
2272	  The order of allocations remains unchanged. Entropy is generated in
2273	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2274	  configuration have in average 30,000 different possible virtual
2275	  addresses for each memory section.
2276
2277	  If unsure, say Y.
2278
2279config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2280	hex "Physical memory mapping padding" if EXPERT
2281	depends on RANDOMIZE_MEMORY
2282	default "0xa" if MEMORY_HOTPLUG
2283	default "0x0"
2284	range 0x1 0x40 if MEMORY_HOTPLUG
2285	range 0x0 0x40
2286	help
2287	  Define the padding in terabytes added to the existing physical
2288	  memory size during kernel memory randomization. It is useful
2289	  for memory hotplug support but reduces the entropy available for
2290	  address randomization.
2291
2292	  If unsure, leave at the default value.
2293
2294config HOTPLUG_CPU
2295	def_bool y
2296	depends on SMP
2297
2298config BOOTPARAM_HOTPLUG_CPU0
2299	bool "Set default setting of cpu0_hotpluggable"
2300	depends on HOTPLUG_CPU
2301	help
2302	  Set whether default state of cpu0_hotpluggable is on or off.
2303
2304	  Say Y here to enable CPU0 hotplug by default. If this switch
2305	  is turned on, there is no need to give cpu0_hotplug kernel
2306	  parameter and the CPU0 hotplug feature is enabled by default.
2307
2308	  Please note: there are two known CPU0 dependencies if you want
2309	  to enable the CPU0 hotplug feature either by this switch or by
2310	  cpu0_hotplug kernel parameter.
2311
2312	  First, resume from hibernate or suspend always starts from CPU0.
2313	  So hibernate and suspend are prevented if CPU0 is offline.
2314
2315	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2316	  offline if any interrupt can not migrate out of CPU0. There may
2317	  be other CPU0 dependencies.
2318
2319	  Please make sure the dependencies are under your control before
2320	  you enable this feature.
2321
2322	  Say N if you don't want to enable CPU0 hotplug feature by default.
2323	  You still can enable the CPU0 hotplug feature at boot by kernel
2324	  parameter cpu0_hotplug.
2325
2326config DEBUG_HOTPLUG_CPU0
2327	def_bool n
2328	prompt "Debug CPU0 hotplug"
2329	depends on HOTPLUG_CPU
2330	help
2331	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2332	  soon as possible and boots up userspace with CPU0 offlined. User
2333	  can online CPU0 back after boot time.
2334
2335	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2336	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2337	  compilation or giving cpu0_hotplug kernel parameter at boot.
2338
2339	  If unsure, say N.
2340
2341config COMPAT_VDSO
2342	def_bool n
2343	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2344	depends on COMPAT_32
2345	help
2346	  Certain buggy versions of glibc will crash if they are
2347	  presented with a 32-bit vDSO that is not mapped at the address
2348	  indicated in its segment table.
2349
2350	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2351	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2352	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2353	  the only released version with the bug, but OpenSUSE 9
2354	  contains a buggy "glibc 2.3.2".
2355
2356	  The symptom of the bug is that everything crashes on startup, saying:
2357	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2358
2359	  Saying Y here changes the default value of the vdso32 boot
2360	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2361	  This works around the glibc bug but hurts performance.
2362
2363	  If unsure, say N: if you are compiling your own kernel, you
2364	  are unlikely to be using a buggy version of glibc.
2365
2366choice
2367	prompt "vsyscall table for legacy applications"
2368	depends on X86_64
2369	default LEGACY_VSYSCALL_XONLY
2370	help
2371	  Legacy user code that does not know how to find the vDSO expects
2372	  to be able to issue three syscalls by calling fixed addresses in
2373	  kernel space. Since this location is not randomized with ASLR,
2374	  it can be used to assist security vulnerability exploitation.
2375
2376	  This setting can be changed at boot time via the kernel command
2377	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2378	  is deprecated and can only be enabled using the kernel command
2379	  line.
2380
2381	  On a system with recent enough glibc (2.14 or newer) and no
2382	  static binaries, you can say None without a performance penalty
2383	  to improve security.
2384
2385	  If unsure, select "Emulate execution only".
2386
2387	config LEGACY_VSYSCALL_XONLY
2388		bool "Emulate execution only"
2389		help
2390		  The kernel traps and emulates calls into the fixed vsyscall
2391		  address mapping and does not allow reads.  This
2392		  configuration is recommended when userspace might use the
2393		  legacy vsyscall area but support for legacy binary
2394		  instrumentation of legacy code is not needed.  It mitigates
2395		  certain uses of the vsyscall area as an ASLR-bypassing
2396		  buffer.
2397
2398	config LEGACY_VSYSCALL_NONE
2399		bool "None"
2400		help
2401		  There will be no vsyscall mapping at all. This will
2402		  eliminate any risk of ASLR bypass due to the vsyscall
2403		  fixed address mapping. Attempts to use the vsyscalls
2404		  will be reported to dmesg, so that either old or
2405		  malicious userspace programs can be identified.
2406
2407endchoice
2408
2409config CMDLINE_BOOL
2410	bool "Built-in kernel command line"
2411	help
2412	  Allow for specifying boot arguments to the kernel at
2413	  build time.  On some systems (e.g. embedded ones), it is
2414	  necessary or convenient to provide some or all of the
2415	  kernel boot arguments with the kernel itself (that is,
2416	  to not rely on the boot loader to provide them.)
2417
2418	  To compile command line arguments into the kernel,
2419	  set this option to 'Y', then fill in the
2420	  boot arguments in CONFIG_CMDLINE.
2421
2422	  Systems with fully functional boot loaders (i.e. non-embedded)
2423	  should leave this option set to 'N'.
2424
2425config CMDLINE
2426	string "Built-in kernel command string"
2427	depends on CMDLINE_BOOL
2428	default ""
2429	help
2430	  Enter arguments here that should be compiled into the kernel
2431	  image and used at boot time.  If the boot loader provides a
2432	  command line at boot time, it is appended to this string to
2433	  form the full kernel command line, when the system boots.
2434
2435	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2436	  change this behavior.
2437
2438	  In most cases, the command line (whether built-in or provided
2439	  by the boot loader) should specify the device for the root
2440	  file system.
2441
2442config CMDLINE_OVERRIDE
2443	bool "Built-in command line overrides boot loader arguments"
2444	depends on CMDLINE_BOOL && CMDLINE != ""
2445	help
2446	  Set this option to 'Y' to have the kernel ignore the boot loader
2447	  command line, and use ONLY the built-in command line.
2448
2449	  This is used to work around broken boot loaders.  This should
2450	  be set to 'N' under normal conditions.
2451
2452config MODIFY_LDT_SYSCALL
2453	bool "Enable the LDT (local descriptor table)" if EXPERT
2454	default y
2455	help
2456	  Linux can allow user programs to install a per-process x86
2457	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2458	  call.  This is required to run 16-bit or segmented code such as
2459	  DOSEMU or some Wine programs.  It is also used by some very old
2460	  threading libraries.
2461
2462	  Enabling this feature adds a small amount of overhead to
2463	  context switches and increases the low-level kernel attack
2464	  surface.  Disabling it removes the modify_ldt(2) system call.
2465
2466	  Saying 'N' here may make sense for embedded or server kernels.
2467
2468config STRICT_SIGALTSTACK_SIZE
2469	bool "Enforce strict size checking for sigaltstack"
2470	depends on DYNAMIC_SIGFRAME
2471	help
2472	  For historical reasons MINSIGSTKSZ is a constant which became
2473	  already too small with AVX512 support. Add a mechanism to
2474	  enforce strict checking of the sigaltstack size against the
2475	  real size of the FPU frame. This option enables the check
2476	  by default. It can also be controlled via the kernel command
2477	  line option 'strict_sas_size' independent of this config
2478	  switch. Enabling it might break existing applications which
2479	  allocate a too small sigaltstack but 'work' because they
2480	  never get a signal delivered.
2481
2482	  Say 'N' unless you want to really enforce this check.
2483
2484source "kernel/livepatch/Kconfig"
2485
2486endmenu
2487
2488config CC_HAS_SLS
2489	def_bool $(cc-option,-mharden-sls=all)
2490
2491config CC_HAS_RETURN_THUNK
2492	def_bool $(cc-option,-mfunction-return=thunk-extern)
2493
2494config CC_HAS_ENTRY_PADDING
2495	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2496
2497config FUNCTION_PADDING_CFI
2498	int
2499	default 59 if FUNCTION_ALIGNMENT_64B
2500	default 27 if FUNCTION_ALIGNMENT_32B
2501	default 11 if FUNCTION_ALIGNMENT_16B
2502	default  3 if FUNCTION_ALIGNMENT_8B
2503	default  0
2504
2505# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2506# except Kconfig can't do arithmetic :/
2507config FUNCTION_PADDING_BYTES
2508	int
2509	default FUNCTION_PADDING_CFI if CFI_CLANG
2510	default FUNCTION_ALIGNMENT
2511
2512config CALL_PADDING
2513	def_bool n
2514	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2515	select FUNCTION_ALIGNMENT_16B
2516
2517config FINEIBT
2518	def_bool y
2519	depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE
2520	select CALL_PADDING
2521
2522config HAVE_CALL_THUNKS
2523	def_bool y
2524	depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL
2525
2526config CALL_THUNKS
2527	def_bool n
2528	select CALL_PADDING
2529
2530config PREFIX_SYMBOLS
2531	def_bool y
2532	depends on CALL_PADDING && !CFI_CLANG
2533
2534menuconfig SPECULATION_MITIGATIONS
2535	bool "Mitigations for speculative execution vulnerabilities"
2536	default y
2537	help
2538	  Say Y here to enable options which enable mitigations for
2539	  speculative execution hardware vulnerabilities.
2540
2541	  If you say N, all mitigations will be disabled. You really
2542	  should know what you are doing to say so.
2543
2544if SPECULATION_MITIGATIONS
2545
2546config PAGE_TABLE_ISOLATION
2547	bool "Remove the kernel mapping in user mode"
2548	default y
2549	depends on (X86_64 || X86_PAE)
2550	help
2551	  This feature reduces the number of hardware side channels by
2552	  ensuring that the majority of kernel addresses are not mapped
2553	  into userspace.
2554
2555	  See Documentation/x86/pti.rst for more details.
2556
2557config RETPOLINE
2558	bool "Avoid speculative indirect branches in kernel"
2559	select OBJTOOL if HAVE_OBJTOOL
2560	default y
2561	help
2562	  Compile kernel with the retpoline compiler options to guard against
2563	  kernel-to-user data leaks by avoiding speculative indirect
2564	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2565	  support for full protection. The kernel may run slower.
2566
2567config RETHUNK
2568	bool "Enable return-thunks"
2569	depends on RETPOLINE && CC_HAS_RETURN_THUNK
2570	select OBJTOOL if HAVE_OBJTOOL
2571	default y if X86_64
2572	help
2573	  Compile the kernel with the return-thunks compiler option to guard
2574	  against kernel-to-user data leaks by avoiding return speculation.
2575	  Requires a compiler with -mfunction-return=thunk-extern
2576	  support for full protection. The kernel may run slower.
2577
2578config CPU_UNRET_ENTRY
2579	bool "Enable UNRET on kernel entry"
2580	depends on CPU_SUP_AMD && RETHUNK && X86_64
2581	default y
2582	help
2583	  Compile the kernel with support for the retbleed=unret mitigation.
2584
2585config CALL_DEPTH_TRACKING
2586	bool "Mitigate RSB underflow with call depth tracking"
2587	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2588	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2589	select CALL_THUNKS
2590	default y
2591	help
2592	  Compile the kernel with call depth tracking to mitigate the Intel
2593	  SKL Return-Speculation-Buffer (RSB) underflow issue. The
2594	  mitigation is off by default and needs to be enabled on the
2595	  kernel command line via the retbleed=stuff option. For
2596	  non-affected systems the overhead of this option is marginal as
2597	  the call depth tracking is using run-time generated call thunks
2598	  in a compiler generated padding area and call patching. This
2599	  increases text size by ~5%. For non affected systems this space
2600	  is unused. On affected SKL systems this results in a significant
2601	  performance gain over the IBRS mitigation.
2602
2603config CALL_THUNKS_DEBUG
2604	bool "Enable call thunks and call depth tracking debugging"
2605	depends on CALL_DEPTH_TRACKING
2606	select FUNCTION_ALIGNMENT_32B
2607	default n
2608	help
2609	  Enable call/ret counters for imbalance detection and build in
2610	  a noisy dmesg about callthunks generation and call patching for
2611	  trouble shooting. The debug prints need to be enabled on the
2612	  kernel command line with 'debug-callthunks'.
2613	  Only enable this when you are debugging call thunks as this
2614	  creates a noticeable runtime overhead. If unsure say N.
2615
2616config CPU_IBPB_ENTRY
2617	bool "Enable IBPB on kernel entry"
2618	depends on CPU_SUP_AMD && X86_64
2619	default y
2620	help
2621	  Compile the kernel with support for the retbleed=ibpb mitigation.
2622
2623config CPU_IBRS_ENTRY
2624	bool "Enable IBRS on kernel entry"
2625	depends on CPU_SUP_INTEL && X86_64
2626	default y
2627	help
2628	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2629	  This mitigates both spectre_v2 and retbleed at great cost to
2630	  performance.
2631
2632config SLS
2633	bool "Mitigate Straight-Line-Speculation"
2634	depends on CC_HAS_SLS && X86_64
2635	select OBJTOOL if HAVE_OBJTOOL
2636	default n
2637	help
2638	  Compile the kernel with straight-line-speculation options to guard
2639	  against straight line speculation. The kernel image might be slightly
2640	  larger.
2641
2642endif
2643
2644config ARCH_HAS_ADD_PAGES
2645	def_bool y
2646	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2647
2648config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2649	def_bool y
2650
2651menu "Power management and ACPI options"
2652
2653config ARCH_HIBERNATION_HEADER
2654	def_bool y
2655	depends on HIBERNATION
2656
2657source "kernel/power/Kconfig"
2658
2659source "drivers/acpi/Kconfig"
2660
2661config X86_APM_BOOT
2662	def_bool y
2663	depends on APM
2664
2665menuconfig APM
2666	tristate "APM (Advanced Power Management) BIOS support"
2667	depends on X86_32 && PM_SLEEP
2668	help
2669	  APM is a BIOS specification for saving power using several different
2670	  techniques. This is mostly useful for battery powered laptops with
2671	  APM compliant BIOSes. If you say Y here, the system time will be
2672	  reset after a RESUME operation, the /proc/apm device will provide
2673	  battery status information, and user-space programs will receive
2674	  notification of APM "events" (e.g. battery status change).
2675
2676	  If you select "Y" here, you can disable actual use of the APM
2677	  BIOS by passing the "apm=off" option to the kernel at boot time.
2678
2679	  Note that the APM support is almost completely disabled for
2680	  machines with more than one CPU.
2681
2682	  In order to use APM, you will need supporting software. For location
2683	  and more information, read <file:Documentation/power/apm-acpi.rst>
2684	  and the Battery Powered Linux mini-HOWTO, available from
2685	  <http://www.tldp.org/docs.html#howto>.
2686
2687	  This driver does not spin down disk drives (see the hdparm(8)
2688	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2689	  VESA-compliant "green" monitors.
2690
2691	  This driver does not support the TI 4000M TravelMate and the ACER
2692	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2693	  desktop machines also don't have compliant BIOSes, and this driver
2694	  may cause those machines to panic during the boot phase.
2695
2696	  Generally, if you don't have a battery in your machine, there isn't
2697	  much point in using this driver and you should say N. If you get
2698	  random kernel OOPSes or reboots that don't seem to be related to
2699	  anything, try disabling/enabling this option (or disabling/enabling
2700	  APM in your BIOS).
2701
2702	  Some other things you should try when experiencing seemingly random,
2703	  "weird" problems:
2704
2705	  1) make sure that you have enough swap space and that it is
2706	  enabled.
2707	  2) pass the "idle=poll" option to the kernel
2708	  3) switch on floating point emulation in the kernel and pass
2709	  the "no387" option to the kernel
2710	  4) pass the "floppy=nodma" option to the kernel
2711	  5) pass the "mem=4M" option to the kernel (thereby disabling
2712	  all but the first 4 MB of RAM)
2713	  6) make sure that the CPU is not over clocked.
2714	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2715	  8) disable the cache from your BIOS settings
2716	  9) install a fan for the video card or exchange video RAM
2717	  10) install a better fan for the CPU
2718	  11) exchange RAM chips
2719	  12) exchange the motherboard.
2720
2721	  To compile this driver as a module, choose M here: the
2722	  module will be called apm.
2723
2724if APM
2725
2726config APM_IGNORE_USER_SUSPEND
2727	bool "Ignore USER SUSPEND"
2728	help
2729	  This option will ignore USER SUSPEND requests. On machines with a
2730	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2731	  series notebooks, it is necessary to say Y because of a BIOS bug.
2732
2733config APM_DO_ENABLE
2734	bool "Enable PM at boot time"
2735	help
2736	  Enable APM features at boot time. From page 36 of the APM BIOS
2737	  specification: "When disabled, the APM BIOS does not automatically
2738	  power manage devices, enter the Standby State, enter the Suspend
2739	  State, or take power saving steps in response to CPU Idle calls."
2740	  This driver will make CPU Idle calls when Linux is idle (unless this
2741	  feature is turned off -- see "Do CPU IDLE calls", below). This
2742	  should always save battery power, but more complicated APM features
2743	  will be dependent on your BIOS implementation. You may need to turn
2744	  this option off if your computer hangs at boot time when using APM
2745	  support, or if it beeps continuously instead of suspending. Turn
2746	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2747	  T400CDT. This is off by default since most machines do fine without
2748	  this feature.
2749
2750config APM_CPU_IDLE
2751	depends on CPU_IDLE
2752	bool "Make CPU Idle calls when idle"
2753	help
2754	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2755	  On some machines, this can activate improved power savings, such as
2756	  a slowed CPU clock rate, when the machine is idle. These idle calls
2757	  are made after the idle loop has run for some length of time (e.g.,
2758	  333 mS). On some machines, this will cause a hang at boot time or
2759	  whenever the CPU becomes idle. (On machines with more than one CPU,
2760	  this option does nothing.)
2761
2762config APM_DISPLAY_BLANK
2763	bool "Enable console blanking using APM"
2764	help
2765	  Enable console blanking using the APM. Some laptops can use this to
2766	  turn off the LCD backlight when the screen blanker of the Linux
2767	  virtual console blanks the screen. Note that this is only used by
2768	  the virtual console screen blanker, and won't turn off the backlight
2769	  when using the X Window system. This also doesn't have anything to
2770	  do with your VESA-compliant power-saving monitor. Further, this
2771	  option doesn't work for all laptops -- it might not turn off your
2772	  backlight at all, or it might print a lot of errors to the console,
2773	  especially if you are using gpm.
2774
2775config APM_ALLOW_INTS
2776	bool "Allow interrupts during APM BIOS calls"
2777	help
2778	  Normally we disable external interrupts while we are making calls to
2779	  the APM BIOS as a measure to lessen the effects of a badly behaving
2780	  BIOS implementation.  The BIOS should reenable interrupts if it
2781	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2782	  many of the newer IBM Thinkpads.  If you experience hangs when you
2783	  suspend, try setting this to Y.  Otherwise, say N.
2784
2785endif # APM
2786
2787source "drivers/cpufreq/Kconfig"
2788
2789source "drivers/cpuidle/Kconfig"
2790
2791source "drivers/idle/Kconfig"
2792
2793endmenu
2794
2795menu "Bus options (PCI etc.)"
2796
2797choice
2798	prompt "PCI access mode"
2799	depends on X86_32 && PCI
2800	default PCI_GOANY
2801	help
2802	  On PCI systems, the BIOS can be used to detect the PCI devices and
2803	  determine their configuration. However, some old PCI motherboards
2804	  have BIOS bugs and may crash if this is done. Also, some embedded
2805	  PCI-based systems don't have any BIOS at all. Linux can also try to
2806	  detect the PCI hardware directly without using the BIOS.
2807
2808	  With this option, you can specify how Linux should detect the
2809	  PCI devices. If you choose "BIOS", the BIOS will be used,
2810	  if you choose "Direct", the BIOS won't be used, and if you
2811	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2812	  If you choose "Any", the kernel will try MMCONFIG, then the
2813	  direct access method and falls back to the BIOS if that doesn't
2814	  work. If unsure, go with the default, which is "Any".
2815
2816config PCI_GOBIOS
2817	bool "BIOS"
2818
2819config PCI_GOMMCONFIG
2820	bool "MMConfig"
2821
2822config PCI_GODIRECT
2823	bool "Direct"
2824
2825config PCI_GOOLPC
2826	bool "OLPC XO-1"
2827	depends on OLPC
2828
2829config PCI_GOANY
2830	bool "Any"
2831
2832endchoice
2833
2834config PCI_BIOS
2835	def_bool y
2836	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2837
2838# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2839config PCI_DIRECT
2840	def_bool y
2841	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2842
2843config PCI_MMCONFIG
2844	bool "Support mmconfig PCI config space access" if X86_64
2845	default y
2846	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2847	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2848
2849config PCI_OLPC
2850	def_bool y
2851	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2852
2853config PCI_XEN
2854	def_bool y
2855	depends on PCI && XEN
2856
2857config MMCONF_FAM10H
2858	def_bool y
2859	depends on X86_64 && PCI_MMCONFIG && ACPI
2860
2861config PCI_CNB20LE_QUIRK
2862	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2863	depends on PCI
2864	help
2865	  Read the PCI windows out of the CNB20LE host bridge. This allows
2866	  PCI hotplug to work on systems with the CNB20LE chipset which do
2867	  not have ACPI.
2868
2869	  There's no public spec for this chipset, and this functionality
2870	  is known to be incomplete.
2871
2872	  You should say N unless you know you need this.
2873
2874config ISA_BUS
2875	bool "ISA bus support on modern systems" if EXPERT
2876	help
2877	  Expose ISA bus device drivers and options available for selection and
2878	  configuration. Enable this option if your target machine has an ISA
2879	  bus. ISA is an older system, displaced by PCI and newer bus
2880	  architectures -- if your target machine is modern, it probably does
2881	  not have an ISA bus.
2882
2883	  If unsure, say N.
2884
2885# x86_64 have no ISA slots, but can have ISA-style DMA.
2886config ISA_DMA_API
2887	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2888	default y
2889	help
2890	  Enables ISA-style DMA support for devices requiring such controllers.
2891	  If unsure, say Y.
2892
2893if X86_32
2894
2895config ISA
2896	bool "ISA support"
2897	help
2898	  Find out whether you have ISA slots on your motherboard.  ISA is the
2899	  name of a bus system, i.e. the way the CPU talks to the other stuff
2900	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2901	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2902	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2903
2904config SCx200
2905	tristate "NatSemi SCx200 support"
2906	help
2907	  This provides basic support for National Semiconductor's
2908	  (now AMD's) Geode processors.  The driver probes for the
2909	  PCI-IDs of several on-chip devices, so its a good dependency
2910	  for other scx200_* drivers.
2911
2912	  If compiled as a module, the driver is named scx200.
2913
2914config SCx200HR_TIMER
2915	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2916	depends on SCx200
2917	default y
2918	help
2919	  This driver provides a clocksource built upon the on-chip
2920	  27MHz high-resolution timer.  Its also a workaround for
2921	  NSC Geode SC-1100's buggy TSC, which loses time when the
2922	  processor goes idle (as is done by the scheduler).  The
2923	  other workaround is idle=poll boot option.
2924
2925config OLPC
2926	bool "One Laptop Per Child support"
2927	depends on !X86_PAE
2928	select GPIOLIB
2929	select OF
2930	select OF_PROMTREE
2931	select IRQ_DOMAIN
2932	select OLPC_EC
2933	help
2934	  Add support for detecting the unique features of the OLPC
2935	  XO hardware.
2936
2937config OLPC_XO1_PM
2938	bool "OLPC XO-1 Power Management"
2939	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2940	help
2941	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2942
2943config OLPC_XO1_RTC
2944	bool "OLPC XO-1 Real Time Clock"
2945	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2946	help
2947	  Add support for the XO-1 real time clock, which can be used as a
2948	  programmable wakeup source.
2949
2950config OLPC_XO1_SCI
2951	bool "OLPC XO-1 SCI extras"
2952	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2953	depends on INPUT=y
2954	select POWER_SUPPLY
2955	help
2956	  Add support for SCI-based features of the OLPC XO-1 laptop:
2957	   - EC-driven system wakeups
2958	   - Power button
2959	   - Ebook switch
2960	   - Lid switch
2961	   - AC adapter status updates
2962	   - Battery status updates
2963
2964config OLPC_XO15_SCI
2965	bool "OLPC XO-1.5 SCI extras"
2966	depends on OLPC && ACPI
2967	select POWER_SUPPLY
2968	help
2969	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2970	   - EC-driven system wakeups
2971	   - AC adapter status updates
2972	   - Battery status updates
2973
2974config ALIX
2975	bool "PCEngines ALIX System Support (LED setup)"
2976	select GPIOLIB
2977	help
2978	  This option enables system support for the PCEngines ALIX.
2979	  At present this just sets up LEDs for GPIO control on
2980	  ALIX2/3/6 boards.  However, other system specific setup should
2981	  get added here.
2982
2983	  Note: You must still enable the drivers for GPIO and LED support
2984	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2985
2986	  Note: You have to set alix.force=1 for boards with Award BIOS.
2987
2988config NET5501
2989	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2990	select GPIOLIB
2991	help
2992	  This option enables system support for the Soekris Engineering net5501.
2993
2994config GEOS
2995	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2996	select GPIOLIB
2997	depends on DMI
2998	help
2999	  This option enables system support for the Traverse Technologies GEOS.
3000
3001config TS5500
3002	bool "Technologic Systems TS-5500 platform support"
3003	depends on MELAN
3004	select CHECK_SIGNATURE
3005	select NEW_LEDS
3006	select LEDS_CLASS
3007	help
3008	  This option enables system support for the Technologic Systems TS-5500.
3009
3010endif # X86_32
3011
3012config AMD_NB
3013	def_bool y
3014	depends on CPU_SUP_AMD && PCI
3015
3016endmenu
3017
3018menu "Binary Emulations"
3019
3020config IA32_EMULATION
3021	bool "IA32 Emulation"
3022	depends on X86_64
3023	select ARCH_WANT_OLD_COMPAT_IPC
3024	select BINFMT_ELF
3025	select COMPAT_OLD_SIGACTION
3026	help
3027	  Include code to run legacy 32-bit programs under a
3028	  64-bit kernel. You should likely turn this on, unless you're
3029	  100% sure that you don't have any 32-bit programs left.
3030
3031config X86_X32_ABI
3032	bool "x32 ABI for 64-bit mode"
3033	depends on X86_64
3034	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3035	# compressed debug sections to x86_x32 properly:
3036	# https://github.com/ClangBuiltLinux/linux/issues/514
3037	# https://github.com/ClangBuiltLinux/linux/issues/1141
3038	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3039	help
3040	  Include code to run binaries for the x32 native 32-bit ABI
3041	  for 64-bit processors.  An x32 process gets access to the
3042	  full 64-bit register file and wide data path while leaving
3043	  pointers at 32 bits for smaller memory footprint.
3044
3045config COMPAT_32
3046	def_bool y
3047	depends on IA32_EMULATION || X86_32
3048	select HAVE_UID16
3049	select OLD_SIGSUSPEND3
3050
3051config COMPAT
3052	def_bool y
3053	depends on IA32_EMULATION || X86_X32_ABI
3054
3055config COMPAT_FOR_U64_ALIGNMENT
3056	def_bool y
3057	depends on COMPAT
3058
3059endmenu
3060
3061config HAVE_ATOMIC_IOMAP
3062	def_bool y
3063	depends on X86_32
3064
3065source "arch/x86/kvm/Kconfig"
3066
3067source "arch/x86/Kconfig.assembler"
3068