xref: /linux/arch/x86/Kconfig (revision eb67d239f3aa1711afb0a42eab50459d9f3d672e)
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_USE_CMPXCHG_LOCKREF
31	select HAVE_ARCH_SOFT_DIRTY
32	select MODULES_USE_ELF_RELA
33	select NEED_DMA_MAP_STATE
34	select SWIOTLB
35	select ARCH_HAS_ELFCORE_COMPAT
36	select ZONE_DMA32
37
38config FORCE_DYNAMIC_FTRACE
39	def_bool y
40	depends on X86_32
41	depends on FUNCTION_TRACER
42	select DYNAMIC_FTRACE
43	help
44	  We keep the static function tracing (!DYNAMIC_FTRACE) around
45	  in order to test the non static function tracing in the
46	  generic code, as other architectures still use it. But we
47	  only need to keep it around for x86_64. No need to keep it
48	  for x86_32. For x86_32, force DYNAMIC_FTRACE.
49#
50# Arch settings
51#
52# ( Note that options that are marked 'if X86_64' could in principle be
53#   ported to 32-bit as well. )
54#
55config X86
56	def_bool y
57	#
58	# Note: keep this list sorted alphabetically
59	#
60	select ACPI_LEGACY_TABLES_LOOKUP	if ACPI
61	select ACPI_SYSTEM_POWER_STATES_SUPPORT	if ACPI
62	select ARCH_32BIT_OFF_T			if X86_32
63	select ARCH_CLOCKSOURCE_INIT
64	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
65	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
66	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
67	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
68	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
69	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
70	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
71	select ARCH_HAS_CACHE_LINE_SIZE
72	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
73	select ARCH_HAS_CURRENT_STACK_POINTER
74	select ARCH_HAS_DEBUG_VIRTUAL
75	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
76	select ARCH_HAS_DEVMEM_IS_ALLOWED
77	select ARCH_HAS_EARLY_DEBUG		if KGDB
78	select ARCH_HAS_ELF_RANDOMIZE
79	select ARCH_HAS_FAST_MULTIPLIER
80	select ARCH_HAS_FORTIFY_SOURCE
81	select ARCH_HAS_GCOV_PROFILE_ALL
82	select ARCH_HAS_KCOV			if X86_64
83	select ARCH_HAS_MEM_ENCRYPT
84	select ARCH_HAS_MEMBARRIER_SYNC_CORE
85	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
86	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
87	select ARCH_HAS_PMEM_API		if X86_64
88	select ARCH_HAS_PTE_DEVMAP		if X86_64
89	select ARCH_HAS_PTE_SPECIAL
90	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
91	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
92	select ARCH_HAS_COPY_MC			if X86_64
93	select ARCH_HAS_SET_MEMORY
94	select ARCH_HAS_SET_DIRECT_MAP
95	select ARCH_HAS_STRICT_KERNEL_RWX
96	select ARCH_HAS_STRICT_MODULE_RWX
97	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
98	select ARCH_HAS_SYSCALL_WRAPPER
99	select ARCH_HAS_UBSAN_SANITIZE_ALL
100	select ARCH_HAS_DEBUG_WX
101	select ARCH_HAS_ZONE_DMA_SET if EXPERT
102	select ARCH_HAVE_NMI_SAFE_CMPXCHG
103	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
104	select ARCH_MIGHT_HAVE_PC_PARPORT
105	select ARCH_MIGHT_HAVE_PC_SERIO
106	select ARCH_STACKWALK
107	select ARCH_SUPPORTS_ACPI
108	select ARCH_SUPPORTS_ATOMIC_RMW
109	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
110	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
111	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
112	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
113	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
114	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
115	select ARCH_SUPPORTS_LTO_CLANG
116	select ARCH_SUPPORTS_LTO_CLANG_THIN
117	select ARCH_USE_BUILTIN_BSWAP
118	select ARCH_USE_MEMTEST
119	select ARCH_USE_QUEUED_RWLOCKS
120	select ARCH_USE_QUEUED_SPINLOCKS
121	select ARCH_USE_SYM_ANNOTATIONS
122	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
123	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
124	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
125	select ARCH_WANTS_NO_INSTR
126	select ARCH_WANT_GENERAL_HUGETLB
127	select ARCH_WANT_HUGE_PMD_SHARE
128	select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP	if X86_64
129	select ARCH_WANT_LD_ORPHAN_WARN
130	select ARCH_WANTS_THP_SWAP		if X86_64
131	select ARCH_HAS_PARANOID_L1D_FLUSH
132	select BUILDTIME_TABLE_SORT
133	select CLKEVT_I8253
134	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
135	select CLOCKSOURCE_WATCHDOG
136	# Word-size accesses may read uninitialized data past the trailing \0
137	# in strings and cause false KMSAN reports.
138	select DCACHE_WORD_ACCESS		if !KMSAN
139	select DYNAMIC_SIGFRAME
140	select EDAC_ATOMIC_SCRUB
141	select EDAC_SUPPORT
142	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
143	select GENERIC_CLOCKEVENTS_MIN_ADJUST
144	select GENERIC_CMOS_UPDATE
145	select GENERIC_CPU_AUTOPROBE
146	select GENERIC_CPU_VULNERABILITIES
147	select GENERIC_EARLY_IOREMAP
148	select GENERIC_ENTRY
149	select GENERIC_IOMAP
150	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
151	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
152	select GENERIC_IRQ_MIGRATION		if SMP
153	select GENERIC_IRQ_PROBE
154	select GENERIC_IRQ_RESERVATION_MODE
155	select GENERIC_IRQ_SHOW
156	select GENERIC_PENDING_IRQ		if SMP
157	select GENERIC_PTDUMP
158	select GENERIC_SMP_IDLE_THREAD
159	select GENERIC_TIME_VSYSCALL
160	select GENERIC_GETTIMEOFDAY
161	select GENERIC_VDSO_TIME_NS
162	select GUP_GET_PTE_LOW_HIGH		if X86_PAE
163	select HARDIRQS_SW_RESEND
164	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
165	select HAVE_ACPI_APEI			if ACPI
166	select HAVE_ACPI_APEI_NMI		if ACPI
167	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
168	select HAVE_ARCH_AUDITSYSCALL
169	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
170	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
171	select HAVE_ARCH_JUMP_LABEL
172	select HAVE_ARCH_JUMP_LABEL_RELATIVE
173	select HAVE_ARCH_KASAN			if X86_64
174	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
175	select HAVE_ARCH_KFENCE
176	select HAVE_ARCH_KMSAN			if X86_64
177	select HAVE_ARCH_KGDB
178	select HAVE_ARCH_MMAP_RND_BITS		if MMU
179	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
180	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
181	select HAVE_ARCH_PREL32_RELOCATIONS
182	select HAVE_ARCH_SECCOMP_FILTER
183	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
184	select HAVE_ARCH_STACKLEAK
185	select HAVE_ARCH_TRACEHOOK
186	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
187	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
188	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
189	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
190	select HAVE_ARCH_VMAP_STACK		if X86_64
191	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
192	select HAVE_ARCH_WITHIN_STACK_FRAMES
193	select HAVE_ASM_MODVERSIONS
194	select HAVE_CMPXCHG_DOUBLE
195	select HAVE_CMPXCHG_LOCAL
196	select HAVE_CONTEXT_TRACKING_USER		if X86_64
197	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
198	select HAVE_C_RECORDMCOUNT
199	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
200	select HAVE_BUILDTIME_MCOUNT_SORT
201	select HAVE_DEBUG_KMEMLEAK
202	select HAVE_DMA_CONTIGUOUS
203	select HAVE_DYNAMIC_FTRACE
204	select HAVE_DYNAMIC_FTRACE_WITH_REGS
205	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
206	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
207	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
208	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
209	select HAVE_EBPF_JIT
210	select HAVE_EFFICIENT_UNALIGNED_ACCESS
211	select HAVE_EISA
212	select HAVE_EXIT_THREAD
213	select HAVE_FAST_GUP
214	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
215	select HAVE_FTRACE_MCOUNT_RECORD
216	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
217	select HAVE_FUNCTION_TRACER
218	select HAVE_GCC_PLUGINS
219	select HAVE_HW_BREAKPOINT
220	select HAVE_IOREMAP_PROT
221	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
222	select HAVE_IRQ_TIME_ACCOUNTING
223	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
224	select HAVE_KERNEL_BZIP2
225	select HAVE_KERNEL_GZIP
226	select HAVE_KERNEL_LZ4
227	select HAVE_KERNEL_LZMA
228	select HAVE_KERNEL_LZO
229	select HAVE_KERNEL_XZ
230	select HAVE_KERNEL_ZSTD
231	select HAVE_KPROBES
232	select HAVE_KPROBES_ON_FTRACE
233	select HAVE_FUNCTION_ERROR_INJECTION
234	select HAVE_KRETPROBES
235	select HAVE_RETHOOK
236	select HAVE_KVM
237	select HAVE_LIVEPATCH			if X86_64
238	select HAVE_MIXED_BREAKPOINTS_REGS
239	select HAVE_MOD_ARCH_SPECIFIC
240	select HAVE_MOVE_PMD
241	select HAVE_MOVE_PUD
242	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
243	select HAVE_NMI
244	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
245	select HAVE_OBJTOOL			if X86_64
246	select HAVE_OPTPROBES
247	select HAVE_PCSPKR_PLATFORM
248	select HAVE_PERF_EVENTS
249	select HAVE_PERF_EVENTS_NMI
250	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
251	select HAVE_PCI
252	select HAVE_PERF_REGS
253	select HAVE_PERF_USER_STACK_DUMP
254	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
255	select MMU_GATHER_MERGE_VMAS
256	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
257	select HAVE_REGS_AND_STACK_ACCESS_API
258	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
259	select HAVE_FUNCTION_ARG_ACCESS_API
260	select HAVE_SETUP_PER_CPU_AREA
261	select HAVE_SOFTIRQ_ON_OWN_STACK
262	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
263	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
264	select HAVE_STATIC_CALL
265	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
266	select HAVE_PREEMPT_DYNAMIC_CALL
267	select HAVE_RSEQ
268	select HAVE_RUST			if X86_64
269	select HAVE_SYSCALL_TRACEPOINTS
270	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
271	select HAVE_UNSTABLE_SCHED_CLOCK
272	select HAVE_USER_RETURN_NOTIFIER
273	select HAVE_GENERIC_VDSO
274	select HOTPLUG_SMT			if SMP
275	select IRQ_FORCED_THREADING
276	select NEED_PER_CPU_EMBED_FIRST_CHUNK
277	select NEED_PER_CPU_PAGE_FIRST_CHUNK
278	select NEED_SG_DMA_LENGTH
279	select PCI_DOMAINS			if PCI
280	select PCI_LOCKLESS_CONFIG		if PCI
281	select PERF_EVENTS
282	select RTC_LIB
283	select RTC_MC146818_LIB
284	select SPARSE_IRQ
285	select SRCU
286	select SYSCTL_EXCEPTION_TRACE
287	select THREAD_INFO_IN_TASK
288	select TRACE_IRQFLAGS_SUPPORT
289	select TRACE_IRQFLAGS_NMI_SUPPORT
290	select USER_STACKTRACE_SUPPORT
291	select HAVE_ARCH_KCSAN			if X86_64
292	select X86_FEATURE_NAMES		if PROC_FS
293	select PROC_PID_ARCH_STATUS		if PROC_FS
294	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
295	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
296	select FUNCTION_ALIGNMENT_4B
297	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
298	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
299
300config INSTRUCTION_DECODER
301	def_bool y
302	depends on KPROBES || PERF_EVENTS || UPROBES
303
304config OUTPUT_FORMAT
305	string
306	default "elf32-i386" if X86_32
307	default "elf64-x86-64" if X86_64
308
309config LOCKDEP_SUPPORT
310	def_bool y
311
312config STACKTRACE_SUPPORT
313	def_bool y
314
315config MMU
316	def_bool y
317
318config ARCH_MMAP_RND_BITS_MIN
319	default 28 if 64BIT
320	default 8
321
322config ARCH_MMAP_RND_BITS_MAX
323	default 32 if 64BIT
324	default 16
325
326config ARCH_MMAP_RND_COMPAT_BITS_MIN
327	default 8
328
329config ARCH_MMAP_RND_COMPAT_BITS_MAX
330	default 16
331
332config SBUS
333	bool
334
335config GENERIC_ISA_DMA
336	def_bool y
337	depends on ISA_DMA_API
338
339config GENERIC_CSUM
340	bool
341	default y if KMSAN || KASAN
342
343config GENERIC_BUG
344	def_bool y
345	depends on BUG
346	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
347
348config GENERIC_BUG_RELATIVE_POINTERS
349	bool
350
351config ARCH_MAY_HAVE_PC_FDC
352	def_bool y
353	depends on ISA_DMA_API
354
355config GENERIC_CALIBRATE_DELAY
356	def_bool y
357
358config ARCH_HAS_CPU_RELAX
359	def_bool y
360
361config ARCH_HIBERNATION_POSSIBLE
362	def_bool y
363
364config ARCH_NR_GPIO
365	int
366	default 1024 if X86_64
367	default 512
368
369config ARCH_SUSPEND_POSSIBLE
370	def_bool y
371
372config AUDIT_ARCH
373	def_bool y if X86_64
374
375config KASAN_SHADOW_OFFSET
376	hex
377	depends on KASAN
378	default 0xdffffc0000000000
379
380config HAVE_INTEL_TXT
381	def_bool y
382	depends on INTEL_IOMMU && ACPI
383
384config X86_32_SMP
385	def_bool y
386	depends on X86_32 && SMP
387
388config X86_64_SMP
389	def_bool y
390	depends on X86_64 && SMP
391
392config ARCH_SUPPORTS_UPROBES
393	def_bool y
394
395config FIX_EARLYCON_MEM
396	def_bool y
397
398config DYNAMIC_PHYSICAL_MASK
399	bool
400
401config PGTABLE_LEVELS
402	int
403	default 5 if X86_5LEVEL
404	default 4 if X86_64
405	default 3 if X86_PAE
406	default 2
407
408config CC_HAS_SANE_STACKPROTECTOR
409	bool
410	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
411	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
412	help
413	  We have to make sure stack protector is unconditionally disabled if
414	  the compiler produces broken code or if it does not let us control
415	  the segment on 32-bit kernels.
416
417menu "Processor type and features"
418
419config SMP
420	bool "Symmetric multi-processing support"
421	help
422	  This enables support for systems with more than one CPU. If you have
423	  a system with only one CPU, say N. If you have a system with more
424	  than one CPU, say Y.
425
426	  If you say N here, the kernel will run on uni- and multiprocessor
427	  machines, but will use only one CPU of a multiprocessor machine. If
428	  you say Y here, the kernel will run on many, but not all,
429	  uniprocessor machines. On a uniprocessor machine, the kernel
430	  will run faster if you say N here.
431
432	  Note that if you say Y here and choose architecture "586" or
433	  "Pentium" under "Processor family", the kernel will not work on 486
434	  architectures. Similarly, multiprocessor kernels for the "PPro"
435	  architecture may not work on all Pentium based boards.
436
437	  People using multiprocessor machines who say Y here should also say
438	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
439	  Management" code will be disabled if you say Y here.
440
441	  See also <file:Documentation/x86/i386/IO-APIC.rst>,
442	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
443	  <http://www.tldp.org/docs.html#howto>.
444
445	  If you don't know what to do here, say N.
446
447config X86_FEATURE_NAMES
448	bool "Processor feature human-readable names" if EMBEDDED
449	default y
450	help
451	  This option compiles in a table of x86 feature bits and corresponding
452	  names.  This is required to support /proc/cpuinfo and a few kernel
453	  messages.  You can disable this to save space, at the expense of
454	  making those few kernel messages show numeric feature bits instead.
455
456	  If in doubt, say Y.
457
458config X86_X2APIC
459	bool "Support x2apic"
460	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
461	help
462	  This enables x2apic support on CPUs that have this feature.
463
464	  This allows 32-bit apic IDs (so it can support very large systems),
465	  and accesses the local apic via MSRs not via mmio.
466
467	  Some Intel systems circa 2022 and later are locked into x2APIC mode
468	  and can not fall back to the legacy APIC modes if SGX or TDX are
469	  enabled in the BIOS. They will boot with very reduced functionality
470	  without enabling this option.
471
472	  If you don't know what to do here, say N.
473
474config X86_MPPARSE
475	bool "Enable MPS table" if ACPI
476	default y
477	depends on X86_LOCAL_APIC
478	help
479	  For old smp systems that do not have proper acpi support. Newer systems
480	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
481
482config GOLDFISH
483	def_bool y
484	depends on X86_GOLDFISH
485
486config X86_CPU_RESCTRL
487	bool "x86 CPU resource control support"
488	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
489	select KERNFS
490	select PROC_CPU_RESCTRL		if PROC_FS
491	help
492	  Enable x86 CPU resource control support.
493
494	  Provide support for the allocation and monitoring of system resources
495	  usage by the CPU.
496
497	  Intel calls this Intel Resource Director Technology
498	  (Intel(R) RDT). More information about RDT can be found in the
499	  Intel x86 Architecture Software Developer Manual.
500
501	  AMD calls this AMD Platform Quality of Service (AMD QoS).
502	  More information about AMD QoS can be found in the AMD64 Technology
503	  Platform Quality of Service Extensions manual.
504
505	  Say N if unsure.
506
507if X86_32
508config X86_BIGSMP
509	bool "Support for big SMP systems with more than 8 CPUs"
510	depends on SMP
511	help
512	  This option is needed for the systems that have more than 8 CPUs.
513
514config X86_EXTENDED_PLATFORM
515	bool "Support for extended (non-PC) x86 platforms"
516	default y
517	help
518	  If you disable this option then the kernel will only support
519	  standard PC platforms. (which covers the vast majority of
520	  systems out there.)
521
522	  If you enable this option then you'll be able to select support
523	  for the following (non-PC) 32 bit x86 platforms:
524		Goldfish (Android emulator)
525		AMD Elan
526		RDC R-321x SoC
527		SGI 320/540 (Visual Workstation)
528		STA2X11-based (e.g. Northville)
529		Moorestown MID devices
530
531	  If you have one of these systems, or if you want to build a
532	  generic distribution kernel, say Y here - otherwise say N.
533endif # X86_32
534
535if X86_64
536config X86_EXTENDED_PLATFORM
537	bool "Support for extended (non-PC) x86 platforms"
538	default y
539	help
540	  If you disable this option then the kernel will only support
541	  standard PC platforms. (which covers the vast majority of
542	  systems out there.)
543
544	  If you enable this option then you'll be able to select support
545	  for the following (non-PC) 64 bit x86 platforms:
546		Numascale NumaChip
547		ScaleMP vSMP
548		SGI Ultraviolet
549
550	  If you have one of these systems, or if you want to build a
551	  generic distribution kernel, say Y here - otherwise say N.
552endif # X86_64
553# This is an alphabetically sorted list of 64 bit extended platforms
554# Please maintain the alphabetic order if and when there are additions
555config X86_NUMACHIP
556	bool "Numascale NumaChip"
557	depends on X86_64
558	depends on X86_EXTENDED_PLATFORM
559	depends on NUMA
560	depends on SMP
561	depends on X86_X2APIC
562	depends on PCI_MMCONFIG
563	help
564	  Adds support for Numascale NumaChip large-SMP systems. Needed to
565	  enable more than ~168 cores.
566	  If you don't have one of these, you should say N here.
567
568config X86_VSMP
569	bool "ScaleMP vSMP"
570	select HYPERVISOR_GUEST
571	select PARAVIRT
572	depends on X86_64 && PCI
573	depends on X86_EXTENDED_PLATFORM
574	depends on SMP
575	help
576	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
577	  supposed to run on these EM64T-based machines.  Only choose this option
578	  if you have one of these machines.
579
580config X86_UV
581	bool "SGI Ultraviolet"
582	depends on X86_64
583	depends on X86_EXTENDED_PLATFORM
584	depends on NUMA
585	depends on EFI
586	depends on KEXEC_CORE
587	depends on X86_X2APIC
588	depends on PCI
589	help
590	  This option is needed in order to support SGI Ultraviolet systems.
591	  If you don't have one of these, you should say N here.
592
593# Following is an alphabetically sorted list of 32 bit extended platforms
594# Please maintain the alphabetic order if and when there are additions
595
596config X86_GOLDFISH
597	bool "Goldfish (Virtual Platform)"
598	depends on X86_EXTENDED_PLATFORM
599	help
600	  Enable support for the Goldfish virtual platform used primarily
601	  for Android development. Unless you are building for the Android
602	  Goldfish emulator say N here.
603
604config X86_INTEL_CE
605	bool "CE4100 TV platform"
606	depends on PCI
607	depends on PCI_GODIRECT
608	depends on X86_IO_APIC
609	depends on X86_32
610	depends on X86_EXTENDED_PLATFORM
611	select X86_REBOOTFIXUPS
612	select OF
613	select OF_EARLY_FLATTREE
614	help
615	  Select for the Intel CE media processor (CE4100) SOC.
616	  This option compiles in support for the CE4100 SOC for settop
617	  boxes and media devices.
618
619config X86_INTEL_MID
620	bool "Intel MID platform support"
621	depends on X86_EXTENDED_PLATFORM
622	depends on X86_PLATFORM_DEVICES
623	depends on PCI
624	depends on X86_64 || (PCI_GOANY && X86_32)
625	depends on X86_IO_APIC
626	select I2C
627	select DW_APB_TIMER
628	select INTEL_SCU_PCI
629	help
630	  Select to build a kernel capable of supporting Intel MID (Mobile
631	  Internet Device) platform systems which do not have the PCI legacy
632	  interfaces. If you are building for a PC class system say N here.
633
634	  Intel MID platforms are based on an Intel processor and chipset which
635	  consume less power than most of the x86 derivatives.
636
637config X86_INTEL_QUARK
638	bool "Intel Quark platform support"
639	depends on X86_32
640	depends on X86_EXTENDED_PLATFORM
641	depends on X86_PLATFORM_DEVICES
642	depends on X86_TSC
643	depends on PCI
644	depends on PCI_GOANY
645	depends on X86_IO_APIC
646	select IOSF_MBI
647	select INTEL_IMR
648	select COMMON_CLK
649	help
650	  Select to include support for Quark X1000 SoC.
651	  Say Y here if you have a Quark based system such as the Arduino
652	  compatible Intel Galileo.
653
654config X86_INTEL_LPSS
655	bool "Intel Low Power Subsystem Support"
656	depends on X86 && ACPI && PCI
657	select COMMON_CLK
658	select PINCTRL
659	select IOSF_MBI
660	help
661	  Select to build support for Intel Low Power Subsystem such as
662	  found on Intel Lynxpoint PCH. Selecting this option enables
663	  things like clock tree (common clock framework) and pincontrol
664	  which are needed by the LPSS peripheral drivers.
665
666config X86_AMD_PLATFORM_DEVICE
667	bool "AMD ACPI2Platform devices support"
668	depends on ACPI
669	select COMMON_CLK
670	select PINCTRL
671	help
672	  Select to interpret AMD specific ACPI device to platform device
673	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
674	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
675	  implemented under PINCTRL subsystem.
676
677config IOSF_MBI
678	tristate "Intel SoC IOSF Sideband support for SoC platforms"
679	depends on PCI
680	help
681	  This option enables sideband register access support for Intel SoC
682	  platforms. On these platforms the IOSF sideband is used in lieu of
683	  MSR's for some register accesses, mostly but not limited to thermal
684	  and power. Drivers may query the availability of this device to
685	  determine if they need the sideband in order to work on these
686	  platforms. The sideband is available on the following SoC products.
687	  This list is not meant to be exclusive.
688	   - BayTrail
689	   - Braswell
690	   - Quark
691
692	  You should say Y if you are running a kernel on one of these SoC's.
693
694config IOSF_MBI_DEBUG
695	bool "Enable IOSF sideband access through debugfs"
696	depends on IOSF_MBI && DEBUG_FS
697	help
698	  Select this option to expose the IOSF sideband access registers (MCR,
699	  MDR, MCRX) through debugfs to write and read register information from
700	  different units on the SoC. This is most useful for obtaining device
701	  state information for debug and analysis. As this is a general access
702	  mechanism, users of this option would have specific knowledge of the
703	  device they want to access.
704
705	  If you don't require the option or are in doubt, say N.
706
707config X86_RDC321X
708	bool "RDC R-321x SoC"
709	depends on X86_32
710	depends on X86_EXTENDED_PLATFORM
711	select M486
712	select X86_REBOOTFIXUPS
713	help
714	  This option is needed for RDC R-321x system-on-chip, also known
715	  as R-8610-(G).
716	  If you don't have one of these chips, you should say N here.
717
718config X86_32_NON_STANDARD
719	bool "Support non-standard 32-bit SMP architectures"
720	depends on X86_32 && SMP
721	depends on X86_EXTENDED_PLATFORM
722	help
723	  This option compiles in the bigsmp and STA2X11 default
724	  subarchitectures.  It is intended for a generic binary
725	  kernel. If you select them all, kernel will probe it one by
726	  one and will fallback to default.
727
728# Alphabetically sorted list of Non standard 32 bit platforms
729
730config X86_SUPPORTS_MEMORY_FAILURE
731	def_bool y
732	# MCE code calls memory_failure():
733	depends on X86_MCE
734	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
735	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
736	depends on X86_64 || !SPARSEMEM
737	select ARCH_SUPPORTS_MEMORY_FAILURE
738
739config STA2X11
740	bool "STA2X11 Companion Chip Support"
741	depends on X86_32_NON_STANDARD && PCI
742	select SWIOTLB
743	select MFD_STA2X11
744	select GPIOLIB
745	help
746	  This adds support for boards based on the STA2X11 IO-Hub,
747	  a.k.a. "ConneXt". The chip is used in place of the standard
748	  PC chipset, so all "standard" peripherals are missing. If this
749	  option is selected the kernel will still be able to boot on
750	  standard PC machines.
751
752config X86_32_IRIS
753	tristate "Eurobraille/Iris poweroff module"
754	depends on X86_32
755	help
756	  The Iris machines from EuroBraille do not have APM or ACPI support
757	  to shut themselves down properly.  A special I/O sequence is
758	  needed to do so, which is what this module does at
759	  kernel shutdown.
760
761	  This is only for Iris machines from EuroBraille.
762
763	  If unused, say N.
764
765config SCHED_OMIT_FRAME_POINTER
766	def_bool y
767	prompt "Single-depth WCHAN output"
768	depends on X86
769	help
770	  Calculate simpler /proc/<PID>/wchan values. If this option
771	  is disabled then wchan values will recurse back to the
772	  caller function. This provides more accurate wchan values,
773	  at the expense of slightly more scheduling overhead.
774
775	  If in doubt, say "Y".
776
777menuconfig HYPERVISOR_GUEST
778	bool "Linux guest support"
779	help
780	  Say Y here to enable options for running Linux under various hyper-
781	  visors. This option enables basic hypervisor detection and platform
782	  setup.
783
784	  If you say N, all options in this submenu will be skipped and
785	  disabled, and Linux guest support won't be built in.
786
787if HYPERVISOR_GUEST
788
789config PARAVIRT
790	bool "Enable paravirtualization code"
791	depends on HAVE_STATIC_CALL
792	help
793	  This changes the kernel so it can modify itself when it is run
794	  under a hypervisor, potentially improving performance significantly
795	  over full virtualization.  However, when run without a hypervisor
796	  the kernel is theoretically slower and slightly larger.
797
798config PARAVIRT_XXL
799	bool
800
801config PARAVIRT_DEBUG
802	bool "paravirt-ops debugging"
803	depends on PARAVIRT && DEBUG_KERNEL
804	help
805	  Enable to debug paravirt_ops internals.  Specifically, BUG if
806	  a paravirt_op is missing when it is called.
807
808config PARAVIRT_SPINLOCKS
809	bool "Paravirtualization layer for spinlocks"
810	depends on PARAVIRT && SMP
811	help
812	  Paravirtualized spinlocks allow a pvops backend to replace the
813	  spinlock implementation with something virtualization-friendly
814	  (for example, block the virtual CPU rather than spinning).
815
816	  It has a minimal impact on native kernels and gives a nice performance
817	  benefit on paravirtualized KVM / Xen kernels.
818
819	  If you are unsure how to answer this question, answer Y.
820
821config X86_HV_CALLBACK_VECTOR
822	def_bool n
823
824source "arch/x86/xen/Kconfig"
825
826config KVM_GUEST
827	bool "KVM Guest support (including kvmclock)"
828	depends on PARAVIRT
829	select PARAVIRT_CLOCK
830	select ARCH_CPUIDLE_HALTPOLL
831	select X86_HV_CALLBACK_VECTOR
832	default y
833	help
834	  This option enables various optimizations for running under the KVM
835	  hypervisor. It includes a paravirtualized clock, so that instead
836	  of relying on a PIT (or probably other) emulation by the
837	  underlying device model, the host provides the guest with
838	  timing infrastructure such as time of day, and system time
839
840config ARCH_CPUIDLE_HALTPOLL
841	def_bool n
842	prompt "Disable host haltpoll when loading haltpoll driver"
843	help
844	  If virtualized under KVM, disable host haltpoll.
845
846config PVH
847	bool "Support for running PVH guests"
848	help
849	  This option enables the PVH entry point for guest virtual machines
850	  as specified in the x86/HVM direct boot ABI.
851
852config PARAVIRT_TIME_ACCOUNTING
853	bool "Paravirtual steal time accounting"
854	depends on PARAVIRT
855	help
856	  Select this option to enable fine granularity task steal time
857	  accounting. Time spent executing other tasks in parallel with
858	  the current vCPU is discounted from the vCPU power. To account for
859	  that, there can be a small performance impact.
860
861	  If in doubt, say N here.
862
863config PARAVIRT_CLOCK
864	bool
865
866config JAILHOUSE_GUEST
867	bool "Jailhouse non-root cell support"
868	depends on X86_64 && PCI
869	select X86_PM_TIMER
870	help
871	  This option allows to run Linux as guest in a Jailhouse non-root
872	  cell. You can leave this option disabled if you only want to start
873	  Jailhouse and run Linux afterwards in the root cell.
874
875config ACRN_GUEST
876	bool "ACRN Guest support"
877	depends on X86_64
878	select X86_HV_CALLBACK_VECTOR
879	help
880	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
881	  a flexible, lightweight reference open-source hypervisor, built with
882	  real-time and safety-criticality in mind. It is built for embedded
883	  IOT with small footprint and real-time features. More details can be
884	  found in https://projectacrn.org/.
885
886config INTEL_TDX_GUEST
887	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
888	depends on X86_64 && CPU_SUP_INTEL
889	depends on X86_X2APIC
890	select ARCH_HAS_CC_PLATFORM
891	select X86_MEM_ENCRYPT
892	select X86_MCE
893	help
894	  Support running as a guest under Intel TDX.  Without this support,
895	  the guest kernel can not boot or run under TDX.
896	  TDX includes memory encryption and integrity capabilities
897	  which protect the confidentiality and integrity of guest
898	  memory contents and CPU state. TDX guests are protected from
899	  some attacks from the VMM.
900
901endif # HYPERVISOR_GUEST
902
903source "arch/x86/Kconfig.cpu"
904
905config HPET_TIMER
906	def_bool X86_64
907	prompt "HPET Timer Support" if X86_32
908	help
909	  Use the IA-PC HPET (High Precision Event Timer) to manage
910	  time in preference to the PIT and RTC, if a HPET is
911	  present.
912	  HPET is the next generation timer replacing legacy 8254s.
913	  The HPET provides a stable time base on SMP
914	  systems, unlike the TSC, but it is more expensive to access,
915	  as it is off-chip.  The interface used is documented
916	  in the HPET spec, revision 1.
917
918	  You can safely choose Y here.  However, HPET will only be
919	  activated if the platform and the BIOS support this feature.
920	  Otherwise the 8254 will be used for timing services.
921
922	  Choose N to continue using the legacy 8254 timer.
923
924config HPET_EMULATE_RTC
925	def_bool y
926	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
927
928# Mark as expert because too many people got it wrong.
929# The code disables itself when not needed.
930config DMI
931	default y
932	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
933	bool "Enable DMI scanning" if EXPERT
934	help
935	  Enabled scanning of DMI to identify machine quirks. Say Y
936	  here unless you have verified that your setup is not
937	  affected by entries in the DMI blacklist. Required by PNP
938	  BIOS code.
939
940config GART_IOMMU
941	bool "Old AMD GART IOMMU support"
942	select DMA_OPS
943	select IOMMU_HELPER
944	select SWIOTLB
945	depends on X86_64 && PCI && AMD_NB
946	help
947	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
948	  GART based hardware IOMMUs.
949
950	  The GART supports full DMA access for devices with 32-bit access
951	  limitations, on systems with more than 3 GB. This is usually needed
952	  for USB, sound, many IDE/SATA chipsets and some other devices.
953
954	  Newer systems typically have a modern AMD IOMMU, supported via
955	  the CONFIG_AMD_IOMMU=y config option.
956
957	  In normal configurations this driver is only active when needed:
958	  there's more than 3 GB of memory and the system contains a
959	  32-bit limited device.
960
961	  If unsure, say Y.
962
963config BOOT_VESA_SUPPORT
964	bool
965	help
966	  If true, at least one selected framebuffer driver can take advantage
967	  of VESA video modes set at an early boot stage via the vga= parameter.
968
969config MAXSMP
970	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
971	depends on X86_64 && SMP && DEBUG_KERNEL
972	select CPUMASK_OFFSTACK
973	help
974	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
975	  If unsure, say N.
976
977#
978# The maximum number of CPUs supported:
979#
980# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
981# and which can be configured interactively in the
982# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
983#
984# The ranges are different on 32-bit and 64-bit kernels, depending on
985# hardware capabilities and scalability features of the kernel.
986#
987# ( If MAXSMP is enabled we just use the highest possible value and disable
988#   interactive configuration. )
989#
990
991config NR_CPUS_RANGE_BEGIN
992	int
993	default NR_CPUS_RANGE_END if MAXSMP
994	default    1 if !SMP
995	default    2
996
997config NR_CPUS_RANGE_END
998	int
999	depends on X86_32
1000	default   64 if  SMP &&  X86_BIGSMP
1001	default    8 if  SMP && !X86_BIGSMP
1002	default    1 if !SMP
1003
1004config NR_CPUS_RANGE_END
1005	int
1006	depends on X86_64
1007	default 8192 if  SMP && CPUMASK_OFFSTACK
1008	default  512 if  SMP && !CPUMASK_OFFSTACK
1009	default    1 if !SMP
1010
1011config NR_CPUS_DEFAULT
1012	int
1013	depends on X86_32
1014	default   32 if  X86_BIGSMP
1015	default    8 if  SMP
1016	default    1 if !SMP
1017
1018config NR_CPUS_DEFAULT
1019	int
1020	depends on X86_64
1021	default 8192 if  MAXSMP
1022	default   64 if  SMP
1023	default    1 if !SMP
1024
1025config NR_CPUS
1026	int "Maximum number of CPUs" if SMP && !MAXSMP
1027	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1028	default NR_CPUS_DEFAULT
1029	help
1030	  This allows you to specify the maximum number of CPUs which this
1031	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1032	  supported value is 8192, otherwise the maximum value is 512.  The
1033	  minimum value which makes sense is 2.
1034
1035	  This is purely to save memory: each supported CPU adds about 8KB
1036	  to the kernel image.
1037
1038config SCHED_CLUSTER
1039	bool "Cluster scheduler support"
1040	depends on SMP
1041	default y
1042	help
1043	  Cluster scheduler support improves the CPU scheduler's decision
1044	  making when dealing with machines that have clusters of CPUs.
1045	  Cluster usually means a couple of CPUs which are placed closely
1046	  by sharing mid-level caches, last-level cache tags or internal
1047	  busses.
1048
1049config SCHED_SMT
1050	def_bool y if SMP
1051
1052config SCHED_MC
1053	def_bool y
1054	prompt "Multi-core scheduler support"
1055	depends on SMP
1056	help
1057	  Multi-core scheduler support improves the CPU scheduler's decision
1058	  making when dealing with multi-core CPU chips at a cost of slightly
1059	  increased overhead in some places. If unsure say N here.
1060
1061config SCHED_MC_PRIO
1062	bool "CPU core priorities scheduler support"
1063	depends on SCHED_MC && CPU_SUP_INTEL
1064	select X86_INTEL_PSTATE
1065	select CPU_FREQ
1066	default y
1067	help
1068	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1069	  core ordering determined at manufacturing time, which allows
1070	  certain cores to reach higher turbo frequencies (when running
1071	  single threaded workloads) than others.
1072
1073	  Enabling this kernel feature teaches the scheduler about
1074	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1075	  scheduler's CPU selection logic accordingly, so that higher
1076	  overall system performance can be achieved.
1077
1078	  This feature will have no effect on CPUs without this feature.
1079
1080	  If unsure say Y here.
1081
1082config UP_LATE_INIT
1083	def_bool y
1084	depends on !SMP && X86_LOCAL_APIC
1085
1086config X86_UP_APIC
1087	bool "Local APIC support on uniprocessors" if !PCI_MSI
1088	default PCI_MSI
1089	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1090	help
1091	  A local APIC (Advanced Programmable Interrupt Controller) is an
1092	  integrated interrupt controller in the CPU. If you have a single-CPU
1093	  system which has a processor with a local APIC, you can say Y here to
1094	  enable and use it. If you say Y here even though your machine doesn't
1095	  have a local APIC, then the kernel will still run with no slowdown at
1096	  all. The local APIC supports CPU-generated self-interrupts (timer,
1097	  performance counters), and the NMI watchdog which detects hard
1098	  lockups.
1099
1100config X86_UP_IOAPIC
1101	bool "IO-APIC support on uniprocessors"
1102	depends on X86_UP_APIC
1103	help
1104	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1105	  SMP-capable replacement for PC-style interrupt controllers. Most
1106	  SMP systems and many recent uniprocessor systems have one.
1107
1108	  If you have a single-CPU system with an IO-APIC, you can say Y here
1109	  to use it. If you say Y here even though your machine doesn't have
1110	  an IO-APIC, then the kernel will still run with no slowdown at all.
1111
1112config X86_LOCAL_APIC
1113	def_bool y
1114	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1115	select IRQ_DOMAIN_HIERARCHY
1116
1117config X86_IO_APIC
1118	def_bool y
1119	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1120
1121config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1122	bool "Reroute for broken boot IRQs"
1123	depends on X86_IO_APIC
1124	help
1125	  This option enables a workaround that fixes a source of
1126	  spurious interrupts. This is recommended when threaded
1127	  interrupt handling is used on systems where the generation of
1128	  superfluous "boot interrupts" cannot be disabled.
1129
1130	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1131	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1132	  kernel does during interrupt handling). On chipsets where this
1133	  boot IRQ generation cannot be disabled, this workaround keeps
1134	  the original IRQ line masked so that only the equivalent "boot
1135	  IRQ" is delivered to the CPUs. The workaround also tells the
1136	  kernel to set up the IRQ handler on the boot IRQ line. In this
1137	  way only one interrupt is delivered to the kernel. Otherwise
1138	  the spurious second interrupt may cause the kernel to bring
1139	  down (vital) interrupt lines.
1140
1141	  Only affects "broken" chipsets. Interrupt sharing may be
1142	  increased on these systems.
1143
1144config X86_MCE
1145	bool "Machine Check / overheating reporting"
1146	select GENERIC_ALLOCATOR
1147	default y
1148	help
1149	  Machine Check support allows the processor to notify the
1150	  kernel if it detects a problem (e.g. overheating, data corruption).
1151	  The action the kernel takes depends on the severity of the problem,
1152	  ranging from warning messages to halting the machine.
1153
1154config X86_MCELOG_LEGACY
1155	bool "Support for deprecated /dev/mcelog character device"
1156	depends on X86_MCE
1157	help
1158	  Enable support for /dev/mcelog which is needed by the old mcelog
1159	  userspace logging daemon. Consider switching to the new generation
1160	  rasdaemon solution.
1161
1162config X86_MCE_INTEL
1163	def_bool y
1164	prompt "Intel MCE features"
1165	depends on X86_MCE && X86_LOCAL_APIC
1166	help
1167	  Additional support for intel specific MCE features such as
1168	  the thermal monitor.
1169
1170config X86_MCE_AMD
1171	def_bool y
1172	prompt "AMD MCE features"
1173	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1174	help
1175	  Additional support for AMD specific MCE features such as
1176	  the DRAM Error Threshold.
1177
1178config X86_ANCIENT_MCE
1179	bool "Support for old Pentium 5 / WinChip machine checks"
1180	depends on X86_32 && X86_MCE
1181	help
1182	  Include support for machine check handling on old Pentium 5 or WinChip
1183	  systems. These typically need to be enabled explicitly on the command
1184	  line.
1185
1186config X86_MCE_THRESHOLD
1187	depends on X86_MCE_AMD || X86_MCE_INTEL
1188	def_bool y
1189
1190config X86_MCE_INJECT
1191	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1192	tristate "Machine check injector support"
1193	help
1194	  Provide support for injecting machine checks for testing purposes.
1195	  If you don't know what a machine check is and you don't do kernel
1196	  QA it is safe to say n.
1197
1198source "arch/x86/events/Kconfig"
1199
1200config X86_LEGACY_VM86
1201	bool "Legacy VM86 support"
1202	depends on X86_32
1203	help
1204	  This option allows user programs to put the CPU into V8086
1205	  mode, which is an 80286-era approximation of 16-bit real mode.
1206
1207	  Some very old versions of X and/or vbetool require this option
1208	  for user mode setting.  Similarly, DOSEMU will use it if
1209	  available to accelerate real mode DOS programs.  However, any
1210	  recent version of DOSEMU, X, or vbetool should be fully
1211	  functional even without kernel VM86 support, as they will all
1212	  fall back to software emulation. Nevertheless, if you are using
1213	  a 16-bit DOS program where 16-bit performance matters, vm86
1214	  mode might be faster than emulation and you might want to
1215	  enable this option.
1216
1217	  Note that any app that works on a 64-bit kernel is unlikely to
1218	  need this option, as 64-bit kernels don't, and can't, support
1219	  V8086 mode. This option is also unrelated to 16-bit protected
1220	  mode and is not needed to run most 16-bit programs under Wine.
1221
1222	  Enabling this option increases the complexity of the kernel
1223	  and slows down exception handling a tiny bit.
1224
1225	  If unsure, say N here.
1226
1227config VM86
1228	bool
1229	default X86_LEGACY_VM86
1230
1231config X86_16BIT
1232	bool "Enable support for 16-bit segments" if EXPERT
1233	default y
1234	depends on MODIFY_LDT_SYSCALL
1235	help
1236	  This option is required by programs like Wine to run 16-bit
1237	  protected mode legacy code on x86 processors.  Disabling
1238	  this option saves about 300 bytes on i386, or around 6K text
1239	  plus 16K runtime memory on x86-64,
1240
1241config X86_ESPFIX32
1242	def_bool y
1243	depends on X86_16BIT && X86_32
1244
1245config X86_ESPFIX64
1246	def_bool y
1247	depends on X86_16BIT && X86_64
1248
1249config X86_VSYSCALL_EMULATION
1250	bool "Enable vsyscall emulation" if EXPERT
1251	default y
1252	depends on X86_64
1253	help
1254	  This enables emulation of the legacy vsyscall page.  Disabling
1255	  it is roughly equivalent to booting with vsyscall=none, except
1256	  that it will also disable the helpful warning if a program
1257	  tries to use a vsyscall.  With this option set to N, offending
1258	  programs will just segfault, citing addresses of the form
1259	  0xffffffffff600?00.
1260
1261	  This option is required by many programs built before 2013, and
1262	  care should be used even with newer programs if set to N.
1263
1264	  Disabling this option saves about 7K of kernel size and
1265	  possibly 4K of additional runtime pagetable memory.
1266
1267config X86_IOPL_IOPERM
1268	bool "IOPERM and IOPL Emulation"
1269	default y
1270	help
1271	  This enables the ioperm() and iopl() syscalls which are necessary
1272	  for legacy applications.
1273
1274	  Legacy IOPL support is an overbroad mechanism which allows user
1275	  space aside of accessing all 65536 I/O ports also to disable
1276	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1277	  capabilities and permission from potentially active security
1278	  modules.
1279
1280	  The emulation restricts the functionality of the syscall to
1281	  only allowing the full range I/O port access, but prevents the
1282	  ability to disable interrupts from user space which would be
1283	  granted if the hardware IOPL mechanism would be used.
1284
1285config TOSHIBA
1286	tristate "Toshiba Laptop support"
1287	depends on X86_32
1288	help
1289	  This adds a driver to safely access the System Management Mode of
1290	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1291	  not work on models with a Phoenix BIOS. The System Management Mode
1292	  is used to set the BIOS and power saving options on Toshiba portables.
1293
1294	  For information on utilities to make use of this driver see the
1295	  Toshiba Linux utilities web site at:
1296	  <http://www.buzzard.org.uk/toshiba/>.
1297
1298	  Say Y if you intend to run this kernel on a Toshiba portable.
1299	  Say N otherwise.
1300
1301config X86_REBOOTFIXUPS
1302	bool "Enable X86 board specific fixups for reboot"
1303	depends on X86_32
1304	help
1305	  This enables chipset and/or board specific fixups to be done
1306	  in order to get reboot to work correctly. This is only needed on
1307	  some combinations of hardware and BIOS. The symptom, for which
1308	  this config is intended, is when reboot ends with a stalled/hung
1309	  system.
1310
1311	  Currently, the only fixup is for the Geode machines using
1312	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1313
1314	  Say Y if you want to enable the fixup. Currently, it's safe to
1315	  enable this option even if you don't need it.
1316	  Say N otherwise.
1317
1318config MICROCODE
1319	bool "CPU microcode loading support"
1320	default y
1321	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1322	help
1323	  If you say Y here, you will be able to update the microcode on
1324	  Intel and AMD processors. The Intel support is for the IA32 family,
1325	  e.g. Pentium Pro, Pentium II, Pentium III, Pentium 4, Xeon etc. The
1326	  AMD support is for families 0x10 and later. You will obviously need
1327	  the actual microcode binary data itself which is not shipped with
1328	  the Linux kernel.
1329
1330	  The preferred method to load microcode from a detached initrd is described
1331	  in Documentation/x86/microcode.rst. For that you need to enable
1332	  CONFIG_BLK_DEV_INITRD in order for the loader to be able to scan the
1333	  initrd for microcode blobs.
1334
1335	  In addition, you can build the microcode into the kernel. For that you
1336	  need to add the vendor-supplied microcode to the CONFIG_EXTRA_FIRMWARE
1337	  config option.
1338
1339config MICROCODE_INTEL
1340	bool "Intel microcode loading support"
1341	depends on CPU_SUP_INTEL && MICROCODE
1342	default MICROCODE
1343	help
1344	  This options enables microcode patch loading support for Intel
1345	  processors.
1346
1347	  For the current Intel microcode data package go to
1348	  <https://downloadcenter.intel.com> and search for
1349	  'Linux Processor Microcode Data File'.
1350
1351config MICROCODE_AMD
1352	bool "AMD microcode loading support"
1353	depends on CPU_SUP_AMD && MICROCODE
1354	help
1355	  If you select this option, microcode patch loading support for AMD
1356	  processors will be enabled.
1357
1358config MICROCODE_LATE_LOADING
1359	bool "Late microcode loading (DANGEROUS)"
1360	default n
1361	depends on MICROCODE
1362	help
1363	  Loading microcode late, when the system is up and executing instructions
1364	  is a tricky business and should be avoided if possible. Just the sequence
1365	  of synchronizing all cores and SMT threads is one fragile dance which does
1366	  not guarantee that cores might not softlock after the loading. Therefore,
1367	  use this at your own risk. Late loading taints the kernel too.
1368
1369config X86_MSR
1370	tristate "/dev/cpu/*/msr - Model-specific register support"
1371	help
1372	  This device gives privileged processes access to the x86
1373	  Model-Specific Registers (MSRs).  It is a character device with
1374	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1375	  MSR accesses are directed to a specific CPU on multi-processor
1376	  systems.
1377
1378config X86_CPUID
1379	tristate "/dev/cpu/*/cpuid - CPU information support"
1380	help
1381	  This device gives processes access to the x86 CPUID instruction to
1382	  be executed on a specific processor.  It is a character device
1383	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1384	  /dev/cpu/31/cpuid.
1385
1386choice
1387	prompt "High Memory Support"
1388	default HIGHMEM4G
1389	depends on X86_32
1390
1391config NOHIGHMEM
1392	bool "off"
1393	help
1394	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1395	  However, the address space of 32-bit x86 processors is only 4
1396	  Gigabytes large. That means that, if you have a large amount of
1397	  physical memory, not all of it can be "permanently mapped" by the
1398	  kernel. The physical memory that's not permanently mapped is called
1399	  "high memory".
1400
1401	  If you are compiling a kernel which will never run on a machine with
1402	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1403	  choice and suitable for most users). This will result in a "3GB/1GB"
1404	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1405	  space and the remaining part of the 4GB virtual memory space is used
1406	  by the kernel to permanently map as much physical memory as
1407	  possible.
1408
1409	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1410	  answer "4GB" here.
1411
1412	  If more than 4 Gigabytes is used then answer "64GB" here. This
1413	  selection turns Intel PAE (Physical Address Extension) mode on.
1414	  PAE implements 3-level paging on IA32 processors. PAE is fully
1415	  supported by Linux, PAE mode is implemented on all recent Intel
1416	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1417	  then the kernel will not boot on CPUs that don't support PAE!
1418
1419	  The actual amount of total physical memory will either be
1420	  auto detected or can be forced by using a kernel command line option
1421	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1422	  your boot loader (lilo or loadlin) about how to pass options to the
1423	  kernel at boot time.)
1424
1425	  If unsure, say "off".
1426
1427config HIGHMEM4G
1428	bool "4GB"
1429	help
1430	  Select this if you have a 32-bit processor and between 1 and 4
1431	  gigabytes of physical RAM.
1432
1433config HIGHMEM64G
1434	bool "64GB"
1435	depends on !M486SX && !M486 && !M586 && !M586TSC && !M586MMX && !MGEODE_LX && !MGEODEGX1 && !MCYRIXIII && !MELAN && !MWINCHIPC6 && !MWINCHIP3D && !MK6
1436	select X86_PAE
1437	help
1438	  Select this if you have a 32-bit processor and more than 4
1439	  gigabytes of physical RAM.
1440
1441endchoice
1442
1443choice
1444	prompt "Memory split" if EXPERT
1445	default VMSPLIT_3G
1446	depends on X86_32
1447	help
1448	  Select the desired split between kernel and user memory.
1449
1450	  If the address range available to the kernel is less than the
1451	  physical memory installed, the remaining memory will be available
1452	  as "high memory". Accessing high memory is a little more costly
1453	  than low memory, as it needs to be mapped into the kernel first.
1454	  Note that increasing the kernel address space limits the range
1455	  available to user programs, making the address space there
1456	  tighter.  Selecting anything other than the default 3G/1G split
1457	  will also likely make your kernel incompatible with binary-only
1458	  kernel modules.
1459
1460	  If you are not absolutely sure what you are doing, leave this
1461	  option alone!
1462
1463	config VMSPLIT_3G
1464		bool "3G/1G user/kernel split"
1465	config VMSPLIT_3G_OPT
1466		depends on !X86_PAE
1467		bool "3G/1G user/kernel split (for full 1G low memory)"
1468	config VMSPLIT_2G
1469		bool "2G/2G user/kernel split"
1470	config VMSPLIT_2G_OPT
1471		depends on !X86_PAE
1472		bool "2G/2G user/kernel split (for full 2G low memory)"
1473	config VMSPLIT_1G
1474		bool "1G/3G user/kernel split"
1475endchoice
1476
1477config PAGE_OFFSET
1478	hex
1479	default 0xB0000000 if VMSPLIT_3G_OPT
1480	default 0x80000000 if VMSPLIT_2G
1481	default 0x78000000 if VMSPLIT_2G_OPT
1482	default 0x40000000 if VMSPLIT_1G
1483	default 0xC0000000
1484	depends on X86_32
1485
1486config HIGHMEM
1487	def_bool y
1488	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1489
1490config X86_PAE
1491	bool "PAE (Physical Address Extension) Support"
1492	depends on X86_32 && !HIGHMEM4G
1493	select PHYS_ADDR_T_64BIT
1494	select SWIOTLB
1495	help
1496	  PAE is required for NX support, and furthermore enables
1497	  larger swapspace support for non-overcommit purposes. It
1498	  has the cost of more pagetable lookup overhead, and also
1499	  consumes more pagetable space per process.
1500
1501config X86_5LEVEL
1502	bool "Enable 5-level page tables support"
1503	default y
1504	select DYNAMIC_MEMORY_LAYOUT
1505	select SPARSEMEM_VMEMMAP
1506	depends on X86_64
1507	help
1508	  5-level paging enables access to larger address space:
1509	  upto 128 PiB of virtual address space and 4 PiB of
1510	  physical address space.
1511
1512	  It will be supported by future Intel CPUs.
1513
1514	  A kernel with the option enabled can be booted on machines that
1515	  support 4- or 5-level paging.
1516
1517	  See Documentation/x86/x86_64/5level-paging.rst for more
1518	  information.
1519
1520	  Say N if unsure.
1521
1522config X86_DIRECT_GBPAGES
1523	def_bool y
1524	depends on X86_64
1525	help
1526	  Certain kernel features effectively disable kernel
1527	  linear 1 GB mappings (even if the CPU otherwise
1528	  supports them), so don't confuse the user by printing
1529	  that we have them enabled.
1530
1531config X86_CPA_STATISTICS
1532	bool "Enable statistic for Change Page Attribute"
1533	depends on DEBUG_FS
1534	help
1535	  Expose statistics about the Change Page Attribute mechanism, which
1536	  helps to determine the effectiveness of preserving large and huge
1537	  page mappings when mapping protections are changed.
1538
1539config X86_MEM_ENCRYPT
1540	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1541	select DYNAMIC_PHYSICAL_MASK
1542	def_bool n
1543
1544config AMD_MEM_ENCRYPT
1545	bool "AMD Secure Memory Encryption (SME) support"
1546	depends on X86_64 && CPU_SUP_AMD
1547	select DMA_COHERENT_POOL
1548	select ARCH_USE_MEMREMAP_PROT
1549	select INSTRUCTION_DECODER
1550	select ARCH_HAS_CC_PLATFORM
1551	select X86_MEM_ENCRYPT
1552	help
1553	  Say yes to enable support for the encryption of system memory.
1554	  This requires an AMD processor that supports Secure Memory
1555	  Encryption (SME).
1556
1557config AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT
1558	bool "Activate AMD Secure Memory Encryption (SME) by default"
1559	depends on AMD_MEM_ENCRYPT
1560	help
1561	  Say yes to have system memory encrypted by default if running on
1562	  an AMD processor that supports Secure Memory Encryption (SME).
1563
1564	  If set to Y, then the encryption of system memory can be
1565	  deactivated with the mem_encrypt=off command line option.
1566
1567	  If set to N, then the encryption of system memory can be
1568	  activated with the mem_encrypt=on command line option.
1569
1570# Common NUMA Features
1571config NUMA
1572	bool "NUMA Memory Allocation and Scheduler Support"
1573	depends on SMP
1574	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1575	default y if X86_BIGSMP
1576	select USE_PERCPU_NUMA_NODE_ID
1577	help
1578	  Enable NUMA (Non-Uniform Memory Access) support.
1579
1580	  The kernel will try to allocate memory used by a CPU on the
1581	  local memory controller of the CPU and add some more
1582	  NUMA awareness to the kernel.
1583
1584	  For 64-bit this is recommended if the system is Intel Core i7
1585	  (or later), AMD Opteron, or EM64T NUMA.
1586
1587	  For 32-bit this is only needed if you boot a 32-bit
1588	  kernel on a 64-bit NUMA platform.
1589
1590	  Otherwise, you should say N.
1591
1592config AMD_NUMA
1593	def_bool y
1594	prompt "Old style AMD Opteron NUMA detection"
1595	depends on X86_64 && NUMA && PCI
1596	help
1597	  Enable AMD NUMA node topology detection.  You should say Y here if
1598	  you have a multi processor AMD system. This uses an old method to
1599	  read the NUMA configuration directly from the builtin Northbridge
1600	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1601	  which also takes priority if both are compiled in.
1602
1603config X86_64_ACPI_NUMA
1604	def_bool y
1605	prompt "ACPI NUMA detection"
1606	depends on X86_64 && NUMA && ACPI && PCI
1607	select ACPI_NUMA
1608	help
1609	  Enable ACPI SRAT based node topology detection.
1610
1611config NUMA_EMU
1612	bool "NUMA emulation"
1613	depends on NUMA
1614	help
1615	  Enable NUMA emulation. A flat machine will be split
1616	  into virtual nodes when booted with "numa=fake=N", where N is the
1617	  number of nodes. This is only useful for debugging.
1618
1619config NODES_SHIFT
1620	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1621	range 1 10
1622	default "10" if MAXSMP
1623	default "6" if X86_64
1624	default "3"
1625	depends on NUMA
1626	help
1627	  Specify the maximum number of NUMA Nodes available on the target
1628	  system.  Increases memory reserved to accommodate various tables.
1629
1630config ARCH_FLATMEM_ENABLE
1631	def_bool y
1632	depends on X86_32 && !NUMA
1633
1634config ARCH_SPARSEMEM_ENABLE
1635	def_bool y
1636	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1637	select SPARSEMEM_STATIC if X86_32
1638	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1639
1640config ARCH_SPARSEMEM_DEFAULT
1641	def_bool X86_64 || (NUMA && X86_32)
1642
1643config ARCH_SELECT_MEMORY_MODEL
1644	def_bool y
1645	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1646
1647config ARCH_MEMORY_PROBE
1648	bool "Enable sysfs memory/probe interface"
1649	depends on MEMORY_HOTPLUG
1650	help
1651	  This option enables a sysfs memory/probe interface for testing.
1652	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1653	  If you are unsure how to answer this question, answer N.
1654
1655config ARCH_PROC_KCORE_TEXT
1656	def_bool y
1657	depends on X86_64 && PROC_KCORE
1658
1659config ILLEGAL_POINTER_VALUE
1660	hex
1661	default 0 if X86_32
1662	default 0xdead000000000000 if X86_64
1663
1664config X86_PMEM_LEGACY_DEVICE
1665	bool
1666
1667config X86_PMEM_LEGACY
1668	tristate "Support non-standard NVDIMMs and ADR protected memory"
1669	depends on PHYS_ADDR_T_64BIT
1670	depends on BLK_DEV
1671	select X86_PMEM_LEGACY_DEVICE
1672	select NUMA_KEEP_MEMINFO if NUMA
1673	select LIBNVDIMM
1674	help
1675	  Treat memory marked using the non-standard e820 type of 12 as used
1676	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1677	  The kernel will offer these regions to the 'pmem' driver so
1678	  they can be used for persistent storage.
1679
1680	  Say Y if unsure.
1681
1682config HIGHPTE
1683	bool "Allocate 3rd-level pagetables from highmem"
1684	depends on HIGHMEM
1685	help
1686	  The VM uses one page table entry for each page of physical memory.
1687	  For systems with a lot of RAM, this can be wasteful of precious
1688	  low memory.  Setting this option will put user-space page table
1689	  entries in high memory.
1690
1691config X86_CHECK_BIOS_CORRUPTION
1692	bool "Check for low memory corruption"
1693	help
1694	  Periodically check for memory corruption in low memory, which
1695	  is suspected to be caused by BIOS.  Even when enabled in the
1696	  configuration, it is disabled at runtime.  Enable it by
1697	  setting "memory_corruption_check=1" on the kernel command
1698	  line.  By default it scans the low 64k of memory every 60
1699	  seconds; see the memory_corruption_check_size and
1700	  memory_corruption_check_period parameters in
1701	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1702
1703	  When enabled with the default parameters, this option has
1704	  almost no overhead, as it reserves a relatively small amount
1705	  of memory and scans it infrequently.  It both detects corruption
1706	  and prevents it from affecting the running system.
1707
1708	  It is, however, intended as a diagnostic tool; if repeatable
1709	  BIOS-originated corruption always affects the same memory,
1710	  you can use memmap= to prevent the kernel from using that
1711	  memory.
1712
1713config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1714	bool "Set the default setting of memory_corruption_check"
1715	depends on X86_CHECK_BIOS_CORRUPTION
1716	default y
1717	help
1718	  Set whether the default state of memory_corruption_check is
1719	  on or off.
1720
1721config MATH_EMULATION
1722	bool
1723	depends on MODIFY_LDT_SYSCALL
1724	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1725	help
1726	  Linux can emulate a math coprocessor (used for floating point
1727	  operations) if you don't have one. 486DX and Pentium processors have
1728	  a math coprocessor built in, 486SX and 386 do not, unless you added
1729	  a 487DX or 387, respectively. (The messages during boot time can
1730	  give you some hints here ["man dmesg"].) Everyone needs either a
1731	  coprocessor or this emulation.
1732
1733	  If you don't have a math coprocessor, you need to say Y here; if you
1734	  say Y here even though you have a coprocessor, the coprocessor will
1735	  be used nevertheless. (This behavior can be changed with the kernel
1736	  command line option "no387", which comes handy if your coprocessor
1737	  is broken. Try "man bootparam" or see the documentation of your boot
1738	  loader (lilo or loadlin) about how to pass options to the kernel at
1739	  boot time.) This means that it is a good idea to say Y here if you
1740	  intend to use this kernel on different machines.
1741
1742	  More information about the internals of the Linux math coprocessor
1743	  emulation can be found in <file:arch/x86/math-emu/README>.
1744
1745	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1746	  kernel, it won't hurt.
1747
1748config MTRR
1749	def_bool y
1750	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1751	help
1752	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1753	  the Memory Type Range Registers (MTRRs) may be used to control
1754	  processor access to memory ranges. This is most useful if you have
1755	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1756	  allows bus write transfers to be combined into a larger transfer
1757	  before bursting over the PCI/AGP bus. This can increase performance
1758	  of image write operations 2.5 times or more. Saying Y here creates a
1759	  /proc/mtrr file which may be used to manipulate your processor's
1760	  MTRRs. Typically the X server should use this.
1761
1762	  This code has a reasonably generic interface so that similar
1763	  control registers on other processors can be easily supported
1764	  as well:
1765
1766	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1767	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1768	  these, the ARRs are used to emulate the MTRRs.
1769	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1770	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1771	  write-combining. All of these processors are supported by this code
1772	  and it makes sense to say Y here if you have one of them.
1773
1774	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1775	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1776	  can lead to all sorts of problems, so it's good to say Y here.
1777
1778	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1779	  just add about 9 KB to your kernel.
1780
1781	  See <file:Documentation/x86/mtrr.rst> for more information.
1782
1783config MTRR_SANITIZER
1784	def_bool y
1785	prompt "MTRR cleanup support"
1786	depends on MTRR
1787	help
1788	  Convert MTRR layout from continuous to discrete, so X drivers can
1789	  add writeback entries.
1790
1791	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1792	  The largest mtrr entry size for a continuous block can be set with
1793	  mtrr_chunk_size.
1794
1795	  If unsure, say Y.
1796
1797config MTRR_SANITIZER_ENABLE_DEFAULT
1798	int "MTRR cleanup enable value (0-1)"
1799	range 0 1
1800	default "0"
1801	depends on MTRR_SANITIZER
1802	help
1803	  Enable mtrr cleanup default value
1804
1805config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1806	int "MTRR cleanup spare reg num (0-7)"
1807	range 0 7
1808	default "1"
1809	depends on MTRR_SANITIZER
1810	help
1811	  mtrr cleanup spare entries default, it can be changed via
1812	  mtrr_spare_reg_nr=N on the kernel command line.
1813
1814config X86_PAT
1815	def_bool y
1816	prompt "x86 PAT support" if EXPERT
1817	depends on MTRR
1818	help
1819	  Use PAT attributes to setup page level cache control.
1820
1821	  PATs are the modern equivalents of MTRRs and are much more
1822	  flexible than MTRRs.
1823
1824	  Say N here if you see bootup problems (boot crash, boot hang,
1825	  spontaneous reboots) or a non-working video driver.
1826
1827	  If unsure, say Y.
1828
1829config ARCH_USES_PG_UNCACHED
1830	def_bool y
1831	depends on X86_PAT
1832
1833config X86_UMIP
1834	def_bool y
1835	prompt "User Mode Instruction Prevention" if EXPERT
1836	help
1837	  User Mode Instruction Prevention (UMIP) is a security feature in
1838	  some x86 processors. If enabled, a general protection fault is
1839	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1840	  executed in user mode. These instructions unnecessarily expose
1841	  information about the hardware state.
1842
1843	  The vast majority of applications do not use these instructions.
1844	  For the very few that do, software emulation is provided in
1845	  specific cases in protected and virtual-8086 modes. Emulated
1846	  results are dummy.
1847
1848config CC_HAS_IBT
1849	# GCC >= 9 and binutils >= 2.29
1850	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1851	# Clang/LLVM >= 14
1852	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1853	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1854	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1855		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1856		  $(as-instr,endbr64)
1857
1858config X86_KERNEL_IBT
1859	prompt "Indirect Branch Tracking"
1860	def_bool y
1861	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1862	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1863	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1864	select OBJTOOL
1865	help
1866	  Build the kernel with support for Indirect Branch Tracking, a
1867	  hardware support course-grain forward-edge Control Flow Integrity
1868	  protection. It enforces that all indirect calls must land on
1869	  an ENDBR instruction, as such, the compiler will instrument the
1870	  code with them to make this happen.
1871
1872	  In addition to building the kernel with IBT, seal all functions that
1873	  are not indirect call targets, avoiding them ever becoming one.
1874
1875	  This requires LTO like objtool runs and will slow down the build. It
1876	  does significantly reduce the number of ENDBR instructions in the
1877	  kernel image.
1878
1879config X86_INTEL_MEMORY_PROTECTION_KEYS
1880	prompt "Memory Protection Keys"
1881	def_bool y
1882	# Note: only available in 64-bit mode
1883	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1884	select ARCH_USES_HIGH_VMA_FLAGS
1885	select ARCH_HAS_PKEYS
1886	help
1887	  Memory Protection Keys provides a mechanism for enforcing
1888	  page-based protections, but without requiring modification of the
1889	  page tables when an application changes protection domains.
1890
1891	  For details, see Documentation/core-api/protection-keys.rst
1892
1893	  If unsure, say y.
1894
1895choice
1896	prompt "TSX enable mode"
1897	depends on CPU_SUP_INTEL
1898	default X86_INTEL_TSX_MODE_OFF
1899	help
1900	  Intel's TSX (Transactional Synchronization Extensions) feature
1901	  allows to optimize locking protocols through lock elision which
1902	  can lead to a noticeable performance boost.
1903
1904	  On the other hand it has been shown that TSX can be exploited
1905	  to form side channel attacks (e.g. TAA) and chances are there
1906	  will be more of those attacks discovered in the future.
1907
1908	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1909	  might override this decision by tsx=on the command line parameter.
1910	  Even with TSX enabled, the kernel will attempt to enable the best
1911	  possible TAA mitigation setting depending on the microcode available
1912	  for the particular machine.
1913
1914	  This option allows to set the default tsx mode between tsx=on, =off
1915	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1916	  details.
1917
1918	  Say off if not sure, auto if TSX is in use but it should be used on safe
1919	  platforms or on if TSX is in use and the security aspect of tsx is not
1920	  relevant.
1921
1922config X86_INTEL_TSX_MODE_OFF
1923	bool "off"
1924	help
1925	  TSX is disabled if possible - equals to tsx=off command line parameter.
1926
1927config X86_INTEL_TSX_MODE_ON
1928	bool "on"
1929	help
1930	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1931	  line parameter.
1932
1933config X86_INTEL_TSX_MODE_AUTO
1934	bool "auto"
1935	help
1936	  TSX is enabled on TSX capable HW that is believed to be safe against
1937	  side channel attacks- equals the tsx=auto command line parameter.
1938endchoice
1939
1940config X86_SGX
1941	bool "Software Guard eXtensions (SGX)"
1942	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1943	depends on CRYPTO=y
1944	depends on CRYPTO_SHA256=y
1945	select SRCU
1946	select MMU_NOTIFIER
1947	select NUMA_KEEP_MEMINFO if NUMA
1948	select XARRAY_MULTI
1949	help
1950	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1951	  that can be used by applications to set aside private regions of code
1952	  and data, referred to as enclaves. An enclave's private memory can
1953	  only be accessed by code running within the enclave. Accesses from
1954	  outside the enclave, including other enclaves, are disallowed by
1955	  hardware.
1956
1957	  If unsure, say N.
1958
1959config EFI
1960	bool "EFI runtime service support"
1961	depends on ACPI
1962	select UCS2_STRING
1963	select EFI_RUNTIME_WRAPPERS
1964	select ARCH_USE_MEMREMAP_PROT
1965	help
1966	  This enables the kernel to use EFI runtime services that are
1967	  available (such as the EFI variable services).
1968
1969	  This option is only useful on systems that have EFI firmware.
1970	  In addition, you should use the latest ELILO loader available
1971	  at <http://elilo.sourceforge.net> in order to take advantage
1972	  of EFI runtime services. However, even with this option, the
1973	  resultant kernel should continue to boot on existing non-EFI
1974	  platforms.
1975
1976config EFI_STUB
1977	bool "EFI stub support"
1978	depends on EFI
1979	select RELOCATABLE
1980	help
1981	  This kernel feature allows a bzImage to be loaded directly
1982	  by EFI firmware without the use of a bootloader.
1983
1984	  See Documentation/admin-guide/efi-stub.rst for more information.
1985
1986config EFI_HANDOVER_PROTOCOL
1987	bool "EFI handover protocol (DEPRECATED)"
1988	depends on EFI_STUB
1989	default y
1990	help
1991	  Select this in order to include support for the deprecated EFI
1992	  handover protocol, which defines alternative entry points into the
1993	  EFI stub.  This is a practice that has no basis in the UEFI
1994	  specification, and requires a priori knowledge on the part of the
1995	  bootloader about Linux/x86 specific ways of passing the command line
1996	  and initrd, and where in memory those assets may be loaded.
1997
1998	  If in doubt, say Y. Even though the corresponding support is not
1999	  present in upstream GRUB or other bootloaders, most distros build
2000	  GRUB with numerous downstream patches applied, and may rely on the
2001	  handover protocol as as result.
2002
2003config EFI_MIXED
2004	bool "EFI mixed-mode support"
2005	depends on EFI_STUB && X86_64
2006	help
2007	  Enabling this feature allows a 64-bit kernel to be booted
2008	  on a 32-bit firmware, provided that your CPU supports 64-bit
2009	  mode.
2010
2011	  Note that it is not possible to boot a mixed-mode enabled
2012	  kernel via the EFI boot stub - a bootloader that supports
2013	  the EFI handover protocol must be used.
2014
2015	  If unsure, say N.
2016
2017config EFI_FAKE_MEMMAP
2018	bool "Enable EFI fake memory map"
2019	depends on EFI
2020	help
2021	  Saying Y here will enable "efi_fake_mem" boot option.  By specifying
2022	  this parameter, you can add arbitrary attribute to specific memory
2023	  range by updating original (firmware provided) EFI memmap.  This is
2024	  useful for debugging of EFI memmap related feature, e.g., Address
2025	  Range Mirroring feature.
2026
2027config EFI_MAX_FAKE_MEM
2028	int "maximum allowable number of ranges in efi_fake_mem boot option"
2029	depends on EFI_FAKE_MEMMAP
2030	range 1 128
2031	default 8
2032	help
2033	  Maximum allowable number of ranges in efi_fake_mem boot option.
2034	  Ranges can be set up to this value using comma-separated list.
2035	  The default value is 8.
2036
2037config EFI_RUNTIME_MAP
2038	bool "Export EFI runtime maps to sysfs" if EXPERT
2039	depends on EFI
2040	default KEXEC_CORE
2041	help
2042	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2043	  That memory map is required by the 2nd kernel to set up EFI virtual
2044	  mappings after kexec, but can also be used for debugging purposes.
2045
2046	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2047
2048source "kernel/Kconfig.hz"
2049
2050config KEXEC
2051	bool "kexec system call"
2052	select KEXEC_CORE
2053	help
2054	  kexec is a system call that implements the ability to shutdown your
2055	  current kernel, and to start another kernel.  It is like a reboot
2056	  but it is independent of the system firmware.   And like a reboot
2057	  you can start any kernel with it, not just Linux.
2058
2059	  The name comes from the similarity to the exec system call.
2060
2061	  It is an ongoing process to be certain the hardware in a machine
2062	  is properly shutdown, so do not be surprised if this code does not
2063	  initially work for you.  As of this writing the exact hardware
2064	  interface is strongly in flux, so no good recommendation can be
2065	  made.
2066
2067config KEXEC_FILE
2068	bool "kexec file based system call"
2069	select KEXEC_CORE
2070	select HAVE_IMA_KEXEC if IMA
2071	depends on X86_64
2072	depends on CRYPTO=y
2073	depends on CRYPTO_SHA256=y
2074	help
2075	  This is new version of kexec system call. This system call is
2076	  file based and takes file descriptors as system call argument
2077	  for kernel and initramfs as opposed to list of segments as
2078	  accepted by previous system call.
2079
2080config ARCH_HAS_KEXEC_PURGATORY
2081	def_bool KEXEC_FILE
2082
2083config KEXEC_SIG
2084	bool "Verify kernel signature during kexec_file_load() syscall"
2085	depends on KEXEC_FILE
2086	help
2087
2088	  This option makes the kexec_file_load() syscall check for a valid
2089	  signature of the kernel image.  The image can still be loaded without
2090	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
2091	  there's a signature that we can check, then it must be valid.
2092
2093	  In addition to this option, you need to enable signature
2094	  verification for the corresponding kernel image type being
2095	  loaded in order for this to work.
2096
2097config KEXEC_SIG_FORCE
2098	bool "Require a valid signature in kexec_file_load() syscall"
2099	depends on KEXEC_SIG
2100	help
2101	  This option makes kernel signature verification mandatory for
2102	  the kexec_file_load() syscall.
2103
2104config KEXEC_BZIMAGE_VERIFY_SIG
2105	bool "Enable bzImage signature verification support"
2106	depends on KEXEC_SIG
2107	depends on SIGNED_PE_FILE_VERIFICATION
2108	select SYSTEM_TRUSTED_KEYRING
2109	help
2110	  Enable bzImage signature verification support.
2111
2112config CRASH_DUMP
2113	bool "kernel crash dumps"
2114	depends on X86_64 || (X86_32 && HIGHMEM)
2115	help
2116	  Generate crash dump after being started by kexec.
2117	  This should be normally only set in special crash dump kernels
2118	  which are loaded in the main kernel with kexec-tools into
2119	  a specially reserved region and then later executed after
2120	  a crash by kdump/kexec. The crash dump kernel must be compiled
2121	  to a memory address not used by the main kernel or BIOS using
2122	  PHYSICAL_START, or it must be built as a relocatable image
2123	  (CONFIG_RELOCATABLE=y).
2124	  For more details see Documentation/admin-guide/kdump/kdump.rst
2125
2126config KEXEC_JUMP
2127	bool "kexec jump"
2128	depends on KEXEC && HIBERNATION
2129	help
2130	  Jump between original kernel and kexeced kernel and invoke
2131	  code in physical address mode via KEXEC
2132
2133config PHYSICAL_START
2134	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2135	default "0x1000000"
2136	help
2137	  This gives the physical address where the kernel is loaded.
2138
2139	  If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
2140	  bzImage will decompress itself to above physical address and
2141	  run from there. Otherwise, bzImage will run from the address where
2142	  it has been loaded by the boot loader and will ignore above physical
2143	  address.
2144
2145	  In normal kdump cases one does not have to set/change this option
2146	  as now bzImage can be compiled as a completely relocatable image
2147	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2148	  address. This option is mainly useful for the folks who don't want
2149	  to use a bzImage for capturing the crash dump and want to use a
2150	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2151	  to be specifically compiled to run from a specific memory area
2152	  (normally a reserved region) and this option comes handy.
2153
2154	  So if you are using bzImage for capturing the crash dump,
2155	  leave the value here unchanged to 0x1000000 and set
2156	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2157	  for capturing the crash dump change this value to start of
2158	  the reserved region.  In other words, it can be set based on
2159	  the "X" value as specified in the "crashkernel=YM@XM"
2160	  command line boot parameter passed to the panic-ed
2161	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2162	  for more details about crash dumps.
2163
2164	  Usage of bzImage for capturing the crash dump is recommended as
2165	  one does not have to build two kernels. Same kernel can be used
2166	  as production kernel and capture kernel. Above option should have
2167	  gone away after relocatable bzImage support is introduced. But it
2168	  is present because there are users out there who continue to use
2169	  vmlinux for dump capture. This option should go away down the
2170	  line.
2171
2172	  Don't change this unless you know what you are doing.
2173
2174config RELOCATABLE
2175	bool "Build a relocatable kernel"
2176	default y
2177	help
2178	  This builds a kernel image that retains relocation information
2179	  so it can be loaded someplace besides the default 1MB.
2180	  The relocations tend to make the kernel binary about 10% larger,
2181	  but are discarded at runtime.
2182
2183	  One use is for the kexec on panic case where the recovery kernel
2184	  must live at a different physical address than the primary
2185	  kernel.
2186
2187	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2188	  it has been loaded at and the compile time physical address
2189	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2190
2191config RANDOMIZE_BASE
2192	bool "Randomize the address of the kernel image (KASLR)"
2193	depends on RELOCATABLE
2194	default y
2195	help
2196	  In support of Kernel Address Space Layout Randomization (KASLR),
2197	  this randomizes the physical address at which the kernel image
2198	  is decompressed and the virtual address where the kernel
2199	  image is mapped, as a security feature that deters exploit
2200	  attempts relying on knowledge of the location of kernel
2201	  code internals.
2202
2203	  On 64-bit, the kernel physical and virtual addresses are
2204	  randomized separately. The physical address will be anywhere
2205	  between 16MB and the top of physical memory (up to 64TB). The
2206	  virtual address will be randomized from 16MB up to 1GB (9 bits
2207	  of entropy). Note that this also reduces the memory space
2208	  available to kernel modules from 1.5GB to 1GB.
2209
2210	  On 32-bit, the kernel physical and virtual addresses are
2211	  randomized together. They will be randomized from 16MB up to
2212	  512MB (8 bits of entropy).
2213
2214	  Entropy is generated using the RDRAND instruction if it is
2215	  supported. If RDTSC is supported, its value is mixed into
2216	  the entropy pool as well. If neither RDRAND nor RDTSC are
2217	  supported, then entropy is read from the i8254 timer. The
2218	  usable entropy is limited by the kernel being built using
2219	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2220	  minimum of 2MB. As a result, only 10 bits of entropy are
2221	  theoretically possible, but the implementations are further
2222	  limited due to memory layouts.
2223
2224	  If unsure, say Y.
2225
2226# Relocation on x86 needs some additional build support
2227config X86_NEED_RELOCS
2228	def_bool y
2229	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2230
2231config PHYSICAL_ALIGN
2232	hex "Alignment value to which kernel should be aligned"
2233	default "0x200000"
2234	range 0x2000 0x1000000 if X86_32
2235	range 0x200000 0x1000000 if X86_64
2236	help
2237	  This value puts the alignment restrictions on physical address
2238	  where kernel is loaded and run from. Kernel is compiled for an
2239	  address which meets above alignment restriction.
2240
2241	  If bootloader loads the kernel at a non-aligned address and
2242	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2243	  address aligned to above value and run from there.
2244
2245	  If bootloader loads the kernel at a non-aligned address and
2246	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2247	  load address and decompress itself to the address it has been
2248	  compiled for and run from there. The address for which kernel is
2249	  compiled already meets above alignment restrictions. Hence the
2250	  end result is that kernel runs from a physical address meeting
2251	  above alignment restrictions.
2252
2253	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2254	  this value must be a multiple of 0x200000.
2255
2256	  Don't change this unless you know what you are doing.
2257
2258config DYNAMIC_MEMORY_LAYOUT
2259	bool
2260	help
2261	  This option makes base addresses of vmalloc and vmemmap as well as
2262	  __PAGE_OFFSET movable during boot.
2263
2264config RANDOMIZE_MEMORY
2265	bool "Randomize the kernel memory sections"
2266	depends on X86_64
2267	depends on RANDOMIZE_BASE
2268	select DYNAMIC_MEMORY_LAYOUT
2269	default RANDOMIZE_BASE
2270	help
2271	  Randomizes the base virtual address of kernel memory sections
2272	  (physical memory mapping, vmalloc & vmemmap). This security feature
2273	  makes exploits relying on predictable memory locations less reliable.
2274
2275	  The order of allocations remains unchanged. Entropy is generated in
2276	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2277	  configuration have in average 30,000 different possible virtual
2278	  addresses for each memory section.
2279
2280	  If unsure, say Y.
2281
2282config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2283	hex "Physical memory mapping padding" if EXPERT
2284	depends on RANDOMIZE_MEMORY
2285	default "0xa" if MEMORY_HOTPLUG
2286	default "0x0"
2287	range 0x1 0x40 if MEMORY_HOTPLUG
2288	range 0x0 0x40
2289	help
2290	  Define the padding in terabytes added to the existing physical
2291	  memory size during kernel memory randomization. It is useful
2292	  for memory hotplug support but reduces the entropy available for
2293	  address randomization.
2294
2295	  If unsure, leave at the default value.
2296
2297config HOTPLUG_CPU
2298	def_bool y
2299	depends on SMP
2300
2301config BOOTPARAM_HOTPLUG_CPU0
2302	bool "Set default setting of cpu0_hotpluggable"
2303	depends on HOTPLUG_CPU
2304	help
2305	  Set whether default state of cpu0_hotpluggable is on or off.
2306
2307	  Say Y here to enable CPU0 hotplug by default. If this switch
2308	  is turned on, there is no need to give cpu0_hotplug kernel
2309	  parameter and the CPU0 hotplug feature is enabled by default.
2310
2311	  Please note: there are two known CPU0 dependencies if you want
2312	  to enable the CPU0 hotplug feature either by this switch or by
2313	  cpu0_hotplug kernel parameter.
2314
2315	  First, resume from hibernate or suspend always starts from CPU0.
2316	  So hibernate and suspend are prevented if CPU0 is offline.
2317
2318	  Second dependency is PIC interrupts always go to CPU0. CPU0 can not
2319	  offline if any interrupt can not migrate out of CPU0. There may
2320	  be other CPU0 dependencies.
2321
2322	  Please make sure the dependencies are under your control before
2323	  you enable this feature.
2324
2325	  Say N if you don't want to enable CPU0 hotplug feature by default.
2326	  You still can enable the CPU0 hotplug feature at boot by kernel
2327	  parameter cpu0_hotplug.
2328
2329config DEBUG_HOTPLUG_CPU0
2330	def_bool n
2331	prompt "Debug CPU0 hotplug"
2332	depends on HOTPLUG_CPU
2333	help
2334	  Enabling this option offlines CPU0 (if CPU0 can be offlined) as
2335	  soon as possible and boots up userspace with CPU0 offlined. User
2336	  can online CPU0 back after boot time.
2337
2338	  To debug CPU0 hotplug, you need to enable CPU0 offline/online
2339	  feature by either turning on CONFIG_BOOTPARAM_HOTPLUG_CPU0 during
2340	  compilation or giving cpu0_hotplug kernel parameter at boot.
2341
2342	  If unsure, say N.
2343
2344config COMPAT_VDSO
2345	def_bool n
2346	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2347	depends on COMPAT_32
2348	help
2349	  Certain buggy versions of glibc will crash if they are
2350	  presented with a 32-bit vDSO that is not mapped at the address
2351	  indicated in its segment table.
2352
2353	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2354	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2355	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2356	  the only released version with the bug, but OpenSUSE 9
2357	  contains a buggy "glibc 2.3.2".
2358
2359	  The symptom of the bug is that everything crashes on startup, saying:
2360	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2361
2362	  Saying Y here changes the default value of the vdso32 boot
2363	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2364	  This works around the glibc bug but hurts performance.
2365
2366	  If unsure, say N: if you are compiling your own kernel, you
2367	  are unlikely to be using a buggy version of glibc.
2368
2369choice
2370	prompt "vsyscall table for legacy applications"
2371	depends on X86_64
2372	default LEGACY_VSYSCALL_XONLY
2373	help
2374	  Legacy user code that does not know how to find the vDSO expects
2375	  to be able to issue three syscalls by calling fixed addresses in
2376	  kernel space. Since this location is not randomized with ASLR,
2377	  it can be used to assist security vulnerability exploitation.
2378
2379	  This setting can be changed at boot time via the kernel command
2380	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2381	  is deprecated and can only be enabled using the kernel command
2382	  line.
2383
2384	  On a system with recent enough glibc (2.14 or newer) and no
2385	  static binaries, you can say None without a performance penalty
2386	  to improve security.
2387
2388	  If unsure, select "Emulate execution only".
2389
2390	config LEGACY_VSYSCALL_XONLY
2391		bool "Emulate execution only"
2392		help
2393		  The kernel traps and emulates calls into the fixed vsyscall
2394		  address mapping and does not allow reads.  This
2395		  configuration is recommended when userspace might use the
2396		  legacy vsyscall area but support for legacy binary
2397		  instrumentation of legacy code is not needed.  It mitigates
2398		  certain uses of the vsyscall area as an ASLR-bypassing
2399		  buffer.
2400
2401	config LEGACY_VSYSCALL_NONE
2402		bool "None"
2403		help
2404		  There will be no vsyscall mapping at all. This will
2405		  eliminate any risk of ASLR bypass due to the vsyscall
2406		  fixed address mapping. Attempts to use the vsyscalls
2407		  will be reported to dmesg, so that either old or
2408		  malicious userspace programs can be identified.
2409
2410endchoice
2411
2412config CMDLINE_BOOL
2413	bool "Built-in kernel command line"
2414	help
2415	  Allow for specifying boot arguments to the kernel at
2416	  build time.  On some systems (e.g. embedded ones), it is
2417	  necessary or convenient to provide some or all of the
2418	  kernel boot arguments with the kernel itself (that is,
2419	  to not rely on the boot loader to provide them.)
2420
2421	  To compile command line arguments into the kernel,
2422	  set this option to 'Y', then fill in the
2423	  boot arguments in CONFIG_CMDLINE.
2424
2425	  Systems with fully functional boot loaders (i.e. non-embedded)
2426	  should leave this option set to 'N'.
2427
2428config CMDLINE
2429	string "Built-in kernel command string"
2430	depends on CMDLINE_BOOL
2431	default ""
2432	help
2433	  Enter arguments here that should be compiled into the kernel
2434	  image and used at boot time.  If the boot loader provides a
2435	  command line at boot time, it is appended to this string to
2436	  form the full kernel command line, when the system boots.
2437
2438	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2439	  change this behavior.
2440
2441	  In most cases, the command line (whether built-in or provided
2442	  by the boot loader) should specify the device for the root
2443	  file system.
2444
2445config CMDLINE_OVERRIDE
2446	bool "Built-in command line overrides boot loader arguments"
2447	depends on CMDLINE_BOOL && CMDLINE != ""
2448	help
2449	  Set this option to 'Y' to have the kernel ignore the boot loader
2450	  command line, and use ONLY the built-in command line.
2451
2452	  This is used to work around broken boot loaders.  This should
2453	  be set to 'N' under normal conditions.
2454
2455config MODIFY_LDT_SYSCALL
2456	bool "Enable the LDT (local descriptor table)" if EXPERT
2457	default y
2458	help
2459	  Linux can allow user programs to install a per-process x86
2460	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2461	  call.  This is required to run 16-bit or segmented code such as
2462	  DOSEMU or some Wine programs.  It is also used by some very old
2463	  threading libraries.
2464
2465	  Enabling this feature adds a small amount of overhead to
2466	  context switches and increases the low-level kernel attack
2467	  surface.  Disabling it removes the modify_ldt(2) system call.
2468
2469	  Saying 'N' here may make sense for embedded or server kernels.
2470
2471config STRICT_SIGALTSTACK_SIZE
2472	bool "Enforce strict size checking for sigaltstack"
2473	depends on DYNAMIC_SIGFRAME
2474	help
2475	  For historical reasons MINSIGSTKSZ is a constant which became
2476	  already too small with AVX512 support. Add a mechanism to
2477	  enforce strict checking of the sigaltstack size against the
2478	  real size of the FPU frame. This option enables the check
2479	  by default. It can also be controlled via the kernel command
2480	  line option 'strict_sas_size' independent of this config
2481	  switch. Enabling it might break existing applications which
2482	  allocate a too small sigaltstack but 'work' because they
2483	  never get a signal delivered.
2484
2485	  Say 'N' unless you want to really enforce this check.
2486
2487source "kernel/livepatch/Kconfig"
2488
2489endmenu
2490
2491config CC_HAS_SLS
2492	def_bool $(cc-option,-mharden-sls=all)
2493
2494config CC_HAS_RETURN_THUNK
2495	def_bool $(cc-option,-mfunction-return=thunk-extern)
2496
2497config CC_HAS_ENTRY_PADDING
2498	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2499
2500config FUNCTION_PADDING_CFI
2501	int
2502	default 59 if FUNCTION_ALIGNMENT_64B
2503	default 27 if FUNCTION_ALIGNMENT_32B
2504	default 11 if FUNCTION_ALIGNMENT_16B
2505	default  3 if FUNCTION_ALIGNMENT_8B
2506	default  0
2507
2508# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2509# except Kconfig can't do arithmetic :/
2510config FUNCTION_PADDING_BYTES
2511	int
2512	default FUNCTION_PADDING_CFI if CFI_CLANG
2513	default FUNCTION_ALIGNMENT
2514
2515config CALL_PADDING
2516	def_bool n
2517	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2518	select FUNCTION_ALIGNMENT_16B
2519
2520config FINEIBT
2521	def_bool y
2522	depends on X86_KERNEL_IBT && CFI_CLANG && RETPOLINE
2523	select CALL_PADDING
2524
2525config HAVE_CALL_THUNKS
2526	def_bool y
2527	depends on CC_HAS_ENTRY_PADDING && RETHUNK && OBJTOOL
2528
2529config CALL_THUNKS
2530	def_bool n
2531	select CALL_PADDING
2532
2533config PREFIX_SYMBOLS
2534	def_bool y
2535	depends on CALL_PADDING && !CFI_CLANG
2536
2537menuconfig SPECULATION_MITIGATIONS
2538	bool "Mitigations for speculative execution vulnerabilities"
2539	default y
2540	help
2541	  Say Y here to enable options which enable mitigations for
2542	  speculative execution hardware vulnerabilities.
2543
2544	  If you say N, all mitigations will be disabled. You really
2545	  should know what you are doing to say so.
2546
2547if SPECULATION_MITIGATIONS
2548
2549config PAGE_TABLE_ISOLATION
2550	bool "Remove the kernel mapping in user mode"
2551	default y
2552	depends on (X86_64 || X86_PAE)
2553	help
2554	  This feature reduces the number of hardware side channels by
2555	  ensuring that the majority of kernel addresses are not mapped
2556	  into userspace.
2557
2558	  See Documentation/x86/pti.rst for more details.
2559
2560config RETPOLINE
2561	bool "Avoid speculative indirect branches in kernel"
2562	select OBJTOOL if HAVE_OBJTOOL
2563	default y
2564	help
2565	  Compile kernel with the retpoline compiler options to guard against
2566	  kernel-to-user data leaks by avoiding speculative indirect
2567	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2568	  support for full protection. The kernel may run slower.
2569
2570config RETHUNK
2571	bool "Enable return-thunks"
2572	depends on RETPOLINE && CC_HAS_RETURN_THUNK
2573	select OBJTOOL if HAVE_OBJTOOL
2574	default y if X86_64
2575	help
2576	  Compile the kernel with the return-thunks compiler option to guard
2577	  against kernel-to-user data leaks by avoiding return speculation.
2578	  Requires a compiler with -mfunction-return=thunk-extern
2579	  support for full protection. The kernel may run slower.
2580
2581config CPU_UNRET_ENTRY
2582	bool "Enable UNRET on kernel entry"
2583	depends on CPU_SUP_AMD && RETHUNK && X86_64
2584	default y
2585	help
2586	  Compile the kernel with support for the retbleed=unret mitigation.
2587
2588config CALL_DEPTH_TRACKING
2589	bool "Mitigate RSB underflow with call depth tracking"
2590	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2591	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2592	select CALL_THUNKS
2593	default y
2594	help
2595	  Compile the kernel with call depth tracking to mitigate the Intel
2596	  SKL Return-Speculation-Buffer (RSB) underflow issue. The
2597	  mitigation is off by default and needs to be enabled on the
2598	  kernel command line via the retbleed=stuff option. For
2599	  non-affected systems the overhead of this option is marginal as
2600	  the call depth tracking is using run-time generated call thunks
2601	  in a compiler generated padding area and call patching. This
2602	  increases text size by ~5%. For non affected systems this space
2603	  is unused. On affected SKL systems this results in a significant
2604	  performance gain over the IBRS mitigation.
2605
2606config CALL_THUNKS_DEBUG
2607	bool "Enable call thunks and call depth tracking debugging"
2608	depends on CALL_DEPTH_TRACKING
2609	select FUNCTION_ALIGNMENT_32B
2610	default n
2611	help
2612	  Enable call/ret counters for imbalance detection and build in
2613	  a noisy dmesg about callthunks generation and call patching for
2614	  trouble shooting. The debug prints need to be enabled on the
2615	  kernel command line with 'debug-callthunks'.
2616	  Only enable this, when you are debugging call thunks as this
2617	  creates a noticable runtime overhead. If unsure say N.
2618
2619config CPU_IBPB_ENTRY
2620	bool "Enable IBPB on kernel entry"
2621	depends on CPU_SUP_AMD && X86_64
2622	default y
2623	help
2624	  Compile the kernel with support for the retbleed=ibpb mitigation.
2625
2626config CPU_IBRS_ENTRY
2627	bool "Enable IBRS on kernel entry"
2628	depends on CPU_SUP_INTEL && X86_64
2629	default y
2630	help
2631	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2632	  This mitigates both spectre_v2 and retbleed at great cost to
2633	  performance.
2634
2635config SLS
2636	bool "Mitigate Straight-Line-Speculation"
2637	depends on CC_HAS_SLS && X86_64
2638	select OBJTOOL if HAVE_OBJTOOL
2639	default n
2640	help
2641	  Compile the kernel with straight-line-speculation options to guard
2642	  against straight line speculation. The kernel image might be slightly
2643	  larger.
2644
2645endif
2646
2647config ARCH_HAS_ADD_PAGES
2648	def_bool y
2649	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2650
2651config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
2652	def_bool y
2653
2654menu "Power management and ACPI options"
2655
2656config ARCH_HIBERNATION_HEADER
2657	def_bool y
2658	depends on HIBERNATION
2659
2660source "kernel/power/Kconfig"
2661
2662source "drivers/acpi/Kconfig"
2663
2664config X86_APM_BOOT
2665	def_bool y
2666	depends on APM
2667
2668menuconfig APM
2669	tristate "APM (Advanced Power Management) BIOS support"
2670	depends on X86_32 && PM_SLEEP
2671	help
2672	  APM is a BIOS specification for saving power using several different
2673	  techniques. This is mostly useful for battery powered laptops with
2674	  APM compliant BIOSes. If you say Y here, the system time will be
2675	  reset after a RESUME operation, the /proc/apm device will provide
2676	  battery status information, and user-space programs will receive
2677	  notification of APM "events" (e.g. battery status change).
2678
2679	  If you select "Y" here, you can disable actual use of the APM
2680	  BIOS by passing the "apm=off" option to the kernel at boot time.
2681
2682	  Note that the APM support is almost completely disabled for
2683	  machines with more than one CPU.
2684
2685	  In order to use APM, you will need supporting software. For location
2686	  and more information, read <file:Documentation/power/apm-acpi.rst>
2687	  and the Battery Powered Linux mini-HOWTO, available from
2688	  <http://www.tldp.org/docs.html#howto>.
2689
2690	  This driver does not spin down disk drives (see the hdparm(8)
2691	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2692	  VESA-compliant "green" monitors.
2693
2694	  This driver does not support the TI 4000M TravelMate and the ACER
2695	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2696	  desktop machines also don't have compliant BIOSes, and this driver
2697	  may cause those machines to panic during the boot phase.
2698
2699	  Generally, if you don't have a battery in your machine, there isn't
2700	  much point in using this driver and you should say N. If you get
2701	  random kernel OOPSes or reboots that don't seem to be related to
2702	  anything, try disabling/enabling this option (or disabling/enabling
2703	  APM in your BIOS).
2704
2705	  Some other things you should try when experiencing seemingly random,
2706	  "weird" problems:
2707
2708	  1) make sure that you have enough swap space and that it is
2709	  enabled.
2710	  2) pass the "idle=poll" option to the kernel
2711	  3) switch on floating point emulation in the kernel and pass
2712	  the "no387" option to the kernel
2713	  4) pass the "floppy=nodma" option to the kernel
2714	  5) pass the "mem=4M" option to the kernel (thereby disabling
2715	  all but the first 4 MB of RAM)
2716	  6) make sure that the CPU is not over clocked.
2717	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2718	  8) disable the cache from your BIOS settings
2719	  9) install a fan for the video card or exchange video RAM
2720	  10) install a better fan for the CPU
2721	  11) exchange RAM chips
2722	  12) exchange the motherboard.
2723
2724	  To compile this driver as a module, choose M here: the
2725	  module will be called apm.
2726
2727if APM
2728
2729config APM_IGNORE_USER_SUSPEND
2730	bool "Ignore USER SUSPEND"
2731	help
2732	  This option will ignore USER SUSPEND requests. On machines with a
2733	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2734	  series notebooks, it is necessary to say Y because of a BIOS bug.
2735
2736config APM_DO_ENABLE
2737	bool "Enable PM at boot time"
2738	help
2739	  Enable APM features at boot time. From page 36 of the APM BIOS
2740	  specification: "When disabled, the APM BIOS does not automatically
2741	  power manage devices, enter the Standby State, enter the Suspend
2742	  State, or take power saving steps in response to CPU Idle calls."
2743	  This driver will make CPU Idle calls when Linux is idle (unless this
2744	  feature is turned off -- see "Do CPU IDLE calls", below). This
2745	  should always save battery power, but more complicated APM features
2746	  will be dependent on your BIOS implementation. You may need to turn
2747	  this option off if your computer hangs at boot time when using APM
2748	  support, or if it beeps continuously instead of suspending. Turn
2749	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2750	  T400CDT. This is off by default since most machines do fine without
2751	  this feature.
2752
2753config APM_CPU_IDLE
2754	depends on CPU_IDLE
2755	bool "Make CPU Idle calls when idle"
2756	help
2757	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2758	  On some machines, this can activate improved power savings, such as
2759	  a slowed CPU clock rate, when the machine is idle. These idle calls
2760	  are made after the idle loop has run for some length of time (e.g.,
2761	  333 mS). On some machines, this will cause a hang at boot time or
2762	  whenever the CPU becomes idle. (On machines with more than one CPU,
2763	  this option does nothing.)
2764
2765config APM_DISPLAY_BLANK
2766	bool "Enable console blanking using APM"
2767	help
2768	  Enable console blanking using the APM. Some laptops can use this to
2769	  turn off the LCD backlight when the screen blanker of the Linux
2770	  virtual console blanks the screen. Note that this is only used by
2771	  the virtual console screen blanker, and won't turn off the backlight
2772	  when using the X Window system. This also doesn't have anything to
2773	  do with your VESA-compliant power-saving monitor. Further, this
2774	  option doesn't work for all laptops -- it might not turn off your
2775	  backlight at all, or it might print a lot of errors to the console,
2776	  especially if you are using gpm.
2777
2778config APM_ALLOW_INTS
2779	bool "Allow interrupts during APM BIOS calls"
2780	help
2781	  Normally we disable external interrupts while we are making calls to
2782	  the APM BIOS as a measure to lessen the effects of a badly behaving
2783	  BIOS implementation.  The BIOS should reenable interrupts if it
2784	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2785	  many of the newer IBM Thinkpads.  If you experience hangs when you
2786	  suspend, try setting this to Y.  Otherwise, say N.
2787
2788endif # APM
2789
2790source "drivers/cpufreq/Kconfig"
2791
2792source "drivers/cpuidle/Kconfig"
2793
2794source "drivers/idle/Kconfig"
2795
2796endmenu
2797
2798menu "Bus options (PCI etc.)"
2799
2800choice
2801	prompt "PCI access mode"
2802	depends on X86_32 && PCI
2803	default PCI_GOANY
2804	help
2805	  On PCI systems, the BIOS can be used to detect the PCI devices and
2806	  determine their configuration. However, some old PCI motherboards
2807	  have BIOS bugs and may crash if this is done. Also, some embedded
2808	  PCI-based systems don't have any BIOS at all. Linux can also try to
2809	  detect the PCI hardware directly without using the BIOS.
2810
2811	  With this option, you can specify how Linux should detect the
2812	  PCI devices. If you choose "BIOS", the BIOS will be used,
2813	  if you choose "Direct", the BIOS won't be used, and if you
2814	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2815	  If you choose "Any", the kernel will try MMCONFIG, then the
2816	  direct access method and falls back to the BIOS if that doesn't
2817	  work. If unsure, go with the default, which is "Any".
2818
2819config PCI_GOBIOS
2820	bool "BIOS"
2821
2822config PCI_GOMMCONFIG
2823	bool "MMConfig"
2824
2825config PCI_GODIRECT
2826	bool "Direct"
2827
2828config PCI_GOOLPC
2829	bool "OLPC XO-1"
2830	depends on OLPC
2831
2832config PCI_GOANY
2833	bool "Any"
2834
2835endchoice
2836
2837config PCI_BIOS
2838	def_bool y
2839	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2840
2841# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2842config PCI_DIRECT
2843	def_bool y
2844	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2845
2846config PCI_MMCONFIG
2847	bool "Support mmconfig PCI config space access" if X86_64
2848	default y
2849	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2850	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2851
2852config PCI_OLPC
2853	def_bool y
2854	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2855
2856config PCI_XEN
2857	def_bool y
2858	depends on PCI && XEN
2859
2860config MMCONF_FAM10H
2861	def_bool y
2862	depends on X86_64 && PCI_MMCONFIG && ACPI
2863
2864config PCI_CNB20LE_QUIRK
2865	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2866	depends on PCI
2867	help
2868	  Read the PCI windows out of the CNB20LE host bridge. This allows
2869	  PCI hotplug to work on systems with the CNB20LE chipset which do
2870	  not have ACPI.
2871
2872	  There's no public spec for this chipset, and this functionality
2873	  is known to be incomplete.
2874
2875	  You should say N unless you know you need this.
2876
2877config ISA_BUS
2878	bool "ISA bus support on modern systems" if EXPERT
2879	help
2880	  Expose ISA bus device drivers and options available for selection and
2881	  configuration. Enable this option if your target machine has an ISA
2882	  bus. ISA is an older system, displaced by PCI and newer bus
2883	  architectures -- if your target machine is modern, it probably does
2884	  not have an ISA bus.
2885
2886	  If unsure, say N.
2887
2888# x86_64 have no ISA slots, but can have ISA-style DMA.
2889config ISA_DMA_API
2890	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2891	default y
2892	help
2893	  Enables ISA-style DMA support for devices requiring such controllers.
2894	  If unsure, say Y.
2895
2896if X86_32
2897
2898config ISA
2899	bool "ISA support"
2900	help
2901	  Find out whether you have ISA slots on your motherboard.  ISA is the
2902	  name of a bus system, i.e. the way the CPU talks to the other stuff
2903	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2904	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2905	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2906
2907config SCx200
2908	tristate "NatSemi SCx200 support"
2909	help
2910	  This provides basic support for National Semiconductor's
2911	  (now AMD's) Geode processors.  The driver probes for the
2912	  PCI-IDs of several on-chip devices, so its a good dependency
2913	  for other scx200_* drivers.
2914
2915	  If compiled as a module, the driver is named scx200.
2916
2917config SCx200HR_TIMER
2918	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2919	depends on SCx200
2920	default y
2921	help
2922	  This driver provides a clocksource built upon the on-chip
2923	  27MHz high-resolution timer.  Its also a workaround for
2924	  NSC Geode SC-1100's buggy TSC, which loses time when the
2925	  processor goes idle (as is done by the scheduler).  The
2926	  other workaround is idle=poll boot option.
2927
2928config OLPC
2929	bool "One Laptop Per Child support"
2930	depends on !X86_PAE
2931	select GPIOLIB
2932	select OF
2933	select OF_PROMTREE
2934	select IRQ_DOMAIN
2935	select OLPC_EC
2936	help
2937	  Add support for detecting the unique features of the OLPC
2938	  XO hardware.
2939
2940config OLPC_XO1_PM
2941	bool "OLPC XO-1 Power Management"
2942	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2943	help
2944	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2945
2946config OLPC_XO1_RTC
2947	bool "OLPC XO-1 Real Time Clock"
2948	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2949	help
2950	  Add support for the XO-1 real time clock, which can be used as a
2951	  programmable wakeup source.
2952
2953config OLPC_XO1_SCI
2954	bool "OLPC XO-1 SCI extras"
2955	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2956	depends on INPUT=y
2957	select POWER_SUPPLY
2958	help
2959	  Add support for SCI-based features of the OLPC XO-1 laptop:
2960	   - EC-driven system wakeups
2961	   - Power button
2962	   - Ebook switch
2963	   - Lid switch
2964	   - AC adapter status updates
2965	   - Battery status updates
2966
2967config OLPC_XO15_SCI
2968	bool "OLPC XO-1.5 SCI extras"
2969	depends on OLPC && ACPI
2970	select POWER_SUPPLY
2971	help
2972	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2973	   - EC-driven system wakeups
2974	   - AC adapter status updates
2975	   - Battery status updates
2976
2977config ALIX
2978	bool "PCEngines ALIX System Support (LED setup)"
2979	select GPIOLIB
2980	help
2981	  This option enables system support for the PCEngines ALIX.
2982	  At present this just sets up LEDs for GPIO control on
2983	  ALIX2/3/6 boards.  However, other system specific setup should
2984	  get added here.
2985
2986	  Note: You must still enable the drivers for GPIO and LED support
2987	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2988
2989	  Note: You have to set alix.force=1 for boards with Award BIOS.
2990
2991config NET5501
2992	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2993	select GPIOLIB
2994	help
2995	  This option enables system support for the Soekris Engineering net5501.
2996
2997config GEOS
2998	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2999	select GPIOLIB
3000	depends on DMI
3001	help
3002	  This option enables system support for the Traverse Technologies GEOS.
3003
3004config TS5500
3005	bool "Technologic Systems TS-5500 platform support"
3006	depends on MELAN
3007	select CHECK_SIGNATURE
3008	select NEW_LEDS
3009	select LEDS_CLASS
3010	help
3011	  This option enables system support for the Technologic Systems TS-5500.
3012
3013endif # X86_32
3014
3015config AMD_NB
3016	def_bool y
3017	depends on CPU_SUP_AMD && PCI
3018
3019endmenu
3020
3021menu "Binary Emulations"
3022
3023config IA32_EMULATION
3024	bool "IA32 Emulation"
3025	depends on X86_64
3026	select ARCH_WANT_OLD_COMPAT_IPC
3027	select BINFMT_ELF
3028	select COMPAT_OLD_SIGACTION
3029	help
3030	  Include code to run legacy 32-bit programs under a
3031	  64-bit kernel. You should likely turn this on, unless you're
3032	  100% sure that you don't have any 32-bit programs left.
3033
3034config X86_X32_ABI
3035	bool "x32 ABI for 64-bit mode"
3036	depends on X86_64
3037	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3038	# compressed debug sections to x86_x32 properly:
3039	# https://github.com/ClangBuiltLinux/linux/issues/514
3040	# https://github.com/ClangBuiltLinux/linux/issues/1141
3041	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3042	help
3043	  Include code to run binaries for the x32 native 32-bit ABI
3044	  for 64-bit processors.  An x32 process gets access to the
3045	  full 64-bit register file and wide data path while leaving
3046	  pointers at 32 bits for smaller memory footprint.
3047
3048config COMPAT_32
3049	def_bool y
3050	depends on IA32_EMULATION || X86_32
3051	select HAVE_UID16
3052	select OLD_SIGSUSPEND3
3053
3054config COMPAT
3055	def_bool y
3056	depends on IA32_EMULATION || X86_X32_ABI
3057
3058config COMPAT_FOR_U64_ALIGNMENT
3059	def_bool y
3060	depends on COMPAT
3061
3062endmenu
3063
3064config HAVE_ATOMIC_IOMAP
3065	def_bool y
3066	depends on X86_32
3067
3068source "arch/x86/kvm/Kconfig"
3069
3070source "arch/x86/Kconfig.assembler"
3071