xref: /linux/arch/x86/Kconfig (revision eb01fe7abbe2d0b38824d2a93fdb4cc3eaf2ccc1)
1# SPDX-License-Identifier: GPL-2.0
2# Select 32 or 64 bit
3config 64BIT
4	bool "64-bit kernel" if "$(ARCH)" = "x86"
5	default "$(ARCH)" != "i386"
6	help
7	  Say yes to build a 64-bit kernel - formerly known as x86_64
8	  Say no to build a 32-bit kernel - formerly known as i386
9
10config X86_32
11	def_bool y
12	depends on !64BIT
13	# Options that are inherently 32-bit kernel only:
14	select ARCH_WANT_IPC_PARSE_VERSION
15	select CLKSRC_I8253
16	select CLONE_BACKWARDS
17	select GENERIC_VDSO_32
18	select HAVE_DEBUG_STACKOVERFLOW
19	select KMAP_LOCAL
20	select MODULES_USE_ELF_REL
21	select OLD_SIGACTION
22	select ARCH_SPLIT_ARG64
23
24config X86_64
25	def_bool y
26	depends on 64BIT
27	# Options that are inherently 64-bit kernel only:
28	select ARCH_HAS_GIGANTIC_PAGE
29	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
30	select ARCH_SUPPORTS_PER_VMA_LOCK
31	select 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 ACPI_HOTPLUG_CPU			if ACPI_PROCESSOR && HOTPLUG_CPU
63	select ARCH_32BIT_OFF_T			if X86_32
64	select ARCH_CLOCKSOURCE_INIT
65	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
66	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
67	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
68	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
69	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
70	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
71	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
72	select ARCH_HAS_CACHE_LINE_SIZE
73	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
74	select ARCH_HAS_CPU_FINALIZE_INIT
75	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
76	select ARCH_HAS_CURRENT_STACK_POINTER
77	select ARCH_HAS_DEBUG_VIRTUAL
78	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
79	select ARCH_HAS_DEVMEM_IS_ALLOWED
80	select ARCH_HAS_EARLY_DEBUG		if KGDB
81	select ARCH_HAS_ELF_RANDOMIZE
82	select ARCH_HAS_FAST_MULTIPLIER
83	select ARCH_HAS_FORTIFY_SOURCE
84	select ARCH_HAS_GCOV_PROFILE_ALL
85	select ARCH_HAS_KCOV			if X86_64
86	select ARCH_HAS_MEM_ENCRYPT
87	select ARCH_HAS_MEMBARRIER_SYNC_CORE
88	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
89	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
90	select ARCH_HAS_PMEM_API		if X86_64
91	select ARCH_HAS_PTE_DEVMAP		if X86_64
92	select ARCH_HAS_PTE_SPECIAL
93	select ARCH_HAS_HW_PTE_YOUNG
94	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
95	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
96	select ARCH_HAS_COPY_MC			if X86_64
97	select ARCH_HAS_SET_MEMORY
98	select ARCH_HAS_SET_DIRECT_MAP
99	select ARCH_HAS_STRICT_KERNEL_RWX
100	select ARCH_HAS_STRICT_MODULE_RWX
101	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
102	select ARCH_HAS_SYSCALL_WRAPPER
103	select ARCH_HAS_UBSAN
104	select ARCH_HAS_DEBUG_WX
105	select ARCH_HAS_ZONE_DMA_SET if EXPERT
106	select ARCH_HAVE_NMI_SAFE_CMPXCHG
107	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
108	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
109	select ARCH_MIGHT_HAVE_PC_PARPORT
110	select ARCH_MIGHT_HAVE_PC_SERIO
111	select ARCH_STACKWALK
112	select ARCH_SUPPORTS_ACPI
113	select ARCH_SUPPORTS_ATOMIC_RMW
114	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
115	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
116	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
117	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
118	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
119	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
120	select ARCH_SUPPORTS_LTO_CLANG
121	select ARCH_SUPPORTS_LTO_CLANG_THIN
122	select ARCH_USE_BUILTIN_BSWAP
123	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CMPXCHG64
124	select ARCH_USE_MEMTEST
125	select ARCH_USE_QUEUED_RWLOCKS
126	select ARCH_USE_QUEUED_SPINLOCKS
127	select ARCH_USE_SYM_ANNOTATIONS
128	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
129	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
130	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
131	select ARCH_WANTS_NO_INSTR
132	select ARCH_WANT_GENERAL_HUGETLB
133	select ARCH_WANT_HUGE_PMD_SHARE
134	select ARCH_WANT_LD_ORPHAN_WARN
135	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
136	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
137	select ARCH_WANTS_THP_SWAP		if X86_64
138	select ARCH_HAS_PARANOID_L1D_FLUSH
139	select BUILDTIME_TABLE_SORT
140	select CLKEVT_I8253
141	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
142	select CLOCKSOURCE_WATCHDOG
143	# Word-size accesses may read uninitialized data past the trailing \0
144	# in strings and cause false KMSAN reports.
145	select DCACHE_WORD_ACCESS		if !KMSAN
146	select DYNAMIC_SIGFRAME
147	select EDAC_ATOMIC_SCRUB
148	select EDAC_SUPPORT
149	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
150	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
151	select GENERIC_CLOCKEVENTS_MIN_ADJUST
152	select GENERIC_CMOS_UPDATE
153	select GENERIC_CPU_AUTOPROBE
154	select GENERIC_CPU_DEVICES
155	select GENERIC_CPU_VULNERABILITIES
156	select GENERIC_EARLY_IOREMAP
157	select GENERIC_ENTRY
158	select GENERIC_IOMAP
159	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
160	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
161	select GENERIC_IRQ_MIGRATION		if SMP
162	select GENERIC_IRQ_PROBE
163	select GENERIC_IRQ_RESERVATION_MODE
164	select GENERIC_IRQ_SHOW
165	select GENERIC_PENDING_IRQ		if SMP
166	select GENERIC_PTDUMP
167	select GENERIC_SMP_IDLE_THREAD
168	select GENERIC_TIME_VSYSCALL
169	select GENERIC_GETTIMEOFDAY
170	select GENERIC_VDSO_TIME_NS
171	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
172	select HARDIRQS_SW_RESEND
173	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
174	select HAS_IOPORT
175	select HAVE_ACPI_APEI			if ACPI
176	select HAVE_ACPI_APEI_NMI		if ACPI
177	select HAVE_ALIGNED_STRUCT_PAGE
178	select HAVE_ARCH_AUDITSYSCALL
179	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
180	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
181	select HAVE_ARCH_JUMP_LABEL
182	select HAVE_ARCH_JUMP_LABEL_RELATIVE
183	select HAVE_ARCH_KASAN			if X86_64
184	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
185	select HAVE_ARCH_KFENCE
186	select HAVE_ARCH_KMSAN			if X86_64
187	select HAVE_ARCH_KGDB
188	select HAVE_ARCH_MMAP_RND_BITS		if MMU
189	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
190	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
191	select HAVE_ARCH_PREL32_RELOCATIONS
192	select HAVE_ARCH_SECCOMP_FILTER
193	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
194	select HAVE_ARCH_STACKLEAK
195	select HAVE_ARCH_TRACEHOOK
196	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
197	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
198	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
199	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
200	select HAVE_ARCH_VMAP_STACK		if X86_64
201	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
202	select HAVE_ARCH_WITHIN_STACK_FRAMES
203	select HAVE_ASM_MODVERSIONS
204	select HAVE_CMPXCHG_DOUBLE
205	select HAVE_CMPXCHG_LOCAL
206	select HAVE_CONTEXT_TRACKING_USER		if X86_64
207	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
208	select HAVE_C_RECORDMCOUNT
209	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
210	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
211	select HAVE_BUILDTIME_MCOUNT_SORT
212	select HAVE_DEBUG_KMEMLEAK
213	select HAVE_DMA_CONTIGUOUS
214	select HAVE_DYNAMIC_FTRACE
215	select HAVE_DYNAMIC_FTRACE_WITH_REGS
216	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
217	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
218	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
219	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
220	select HAVE_EBPF_JIT
221	select HAVE_EFFICIENT_UNALIGNED_ACCESS
222	select HAVE_EISA
223	select HAVE_EXIT_THREAD
224	select HAVE_FAST_GUP
225	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
226	select HAVE_FTRACE_MCOUNT_RECORD
227	select HAVE_FUNCTION_GRAPH_RETVAL	if HAVE_FUNCTION_GRAPH_TRACER
228	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
229	select HAVE_FUNCTION_TRACER
230	select HAVE_GCC_PLUGINS
231	select HAVE_HW_BREAKPOINT
232	select HAVE_IOREMAP_PROT
233	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
234	select HAVE_IRQ_TIME_ACCOUNTING
235	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
236	select HAVE_KERNEL_BZIP2
237	select HAVE_KERNEL_GZIP
238	select HAVE_KERNEL_LZ4
239	select HAVE_KERNEL_LZMA
240	select HAVE_KERNEL_LZO
241	select HAVE_KERNEL_XZ
242	select HAVE_KERNEL_ZSTD
243	select HAVE_KPROBES
244	select HAVE_KPROBES_ON_FTRACE
245	select HAVE_FUNCTION_ERROR_INJECTION
246	select HAVE_KRETPROBES
247	select HAVE_RETHOOK
248	select HAVE_LIVEPATCH			if X86_64
249	select HAVE_MIXED_BREAKPOINTS_REGS
250	select HAVE_MOD_ARCH_SPECIFIC
251	select HAVE_MOVE_PMD
252	select HAVE_MOVE_PUD
253	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
254	select HAVE_NMI
255	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
256	select HAVE_OBJTOOL			if X86_64
257	select HAVE_OPTPROBES
258	select HAVE_PAGE_SIZE_4KB
259	select HAVE_PCSPKR_PLATFORM
260	select HAVE_PERF_EVENTS
261	select HAVE_PERF_EVENTS_NMI
262	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
263	select HAVE_PCI
264	select HAVE_PERF_REGS
265	select HAVE_PERF_USER_STACK_DUMP
266	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
267	select MMU_GATHER_MERGE_VMAS
268	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
269	select HAVE_REGS_AND_STACK_ACCESS_API
270	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
271	select HAVE_FUNCTION_ARG_ACCESS_API
272	select HAVE_SETUP_PER_CPU_AREA
273	select HAVE_SOFTIRQ_ON_OWN_STACK
274	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
275	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
276	select HAVE_STATIC_CALL
277	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
278	select HAVE_PREEMPT_DYNAMIC_CALL
279	select HAVE_RSEQ
280	select HAVE_RUST			if X86_64
281	select HAVE_SYSCALL_TRACEPOINTS
282	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
283	select HAVE_UNSTABLE_SCHED_CLOCK
284	select HAVE_USER_RETURN_NOTIFIER
285	select HAVE_GENERIC_VDSO
286	select HOTPLUG_PARALLEL			if SMP && X86_64
287	select HOTPLUG_SMT			if SMP
288	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
289	select IRQ_FORCED_THREADING
290	select LOCK_MM_AND_FIND_VMA
291	select NEED_PER_CPU_EMBED_FIRST_CHUNK
292	select NEED_PER_CPU_PAGE_FIRST_CHUNK
293	select NEED_SG_DMA_LENGTH
294	select PCI_DOMAINS			if PCI
295	select PCI_LOCKLESS_CONFIG		if PCI
296	select PERF_EVENTS
297	select RTC_LIB
298	select RTC_MC146818_LIB
299	select SPARSE_IRQ
300	select SYSCTL_EXCEPTION_TRACE
301	select THREAD_INFO_IN_TASK
302	select TRACE_IRQFLAGS_SUPPORT
303	select TRACE_IRQFLAGS_NMI_SUPPORT
304	select USER_STACKTRACE_SUPPORT
305	select HAVE_ARCH_KCSAN			if X86_64
306	select PROC_PID_ARCH_STATUS		if PROC_FS
307	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
308	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
309	select FUNCTION_ALIGNMENT_4B
310	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
311	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
312
313config INSTRUCTION_DECODER
314	def_bool y
315	depends on KPROBES || PERF_EVENTS || UPROBES
316
317config OUTPUT_FORMAT
318	string
319	default "elf32-i386" if X86_32
320	default "elf64-x86-64" if X86_64
321
322config LOCKDEP_SUPPORT
323	def_bool y
324
325config STACKTRACE_SUPPORT
326	def_bool y
327
328config MMU
329	def_bool y
330
331config ARCH_MMAP_RND_BITS_MIN
332	default 28 if 64BIT
333	default 8
334
335config ARCH_MMAP_RND_BITS_MAX
336	default 32 if 64BIT
337	default 16
338
339config ARCH_MMAP_RND_COMPAT_BITS_MIN
340	default 8
341
342config ARCH_MMAP_RND_COMPAT_BITS_MAX
343	default 16
344
345config SBUS
346	bool
347
348config GENERIC_ISA_DMA
349	def_bool y
350	depends on ISA_DMA_API
351
352config GENERIC_CSUM
353	bool
354	default y if KMSAN || KASAN
355
356config GENERIC_BUG
357	def_bool y
358	depends on BUG
359	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
360
361config GENERIC_BUG_RELATIVE_POINTERS
362	bool
363
364config ARCH_MAY_HAVE_PC_FDC
365	def_bool y
366	depends on ISA_DMA_API
367
368config GENERIC_CALIBRATE_DELAY
369	def_bool y
370
371config ARCH_HAS_CPU_RELAX
372	def_bool y
373
374config ARCH_HIBERNATION_POSSIBLE
375	def_bool y
376
377config ARCH_SUSPEND_POSSIBLE
378	def_bool y
379
380config AUDIT_ARCH
381	def_bool y if X86_64
382
383config KASAN_SHADOW_OFFSET
384	hex
385	depends on KASAN
386	default 0xdffffc0000000000
387
388config HAVE_INTEL_TXT
389	def_bool y
390	depends on INTEL_IOMMU && ACPI
391
392config X86_64_SMP
393	def_bool y
394	depends on X86_64 && SMP
395
396config ARCH_SUPPORTS_UPROBES
397	def_bool y
398
399config FIX_EARLYCON_MEM
400	def_bool y
401
402config DYNAMIC_PHYSICAL_MASK
403	bool
404
405config PGTABLE_LEVELS
406	int
407	default 5 if X86_5LEVEL
408	default 4 if X86_64
409	default 3 if X86_PAE
410	default 2
411
412config CC_HAS_SANE_STACKPROTECTOR
413	bool
414	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
415	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
416	help
417	  We have to make sure stack protector is unconditionally disabled if
418	  the compiler produces broken code or if it does not let us control
419	  the segment on 32-bit kernels.
420
421menu "Processor type and features"
422
423config SMP
424	bool "Symmetric multi-processing support"
425	help
426	  This enables support for systems with more than one CPU. If you have
427	  a system with only one CPU, say N. If you have a system with more
428	  than one CPU, say Y.
429
430	  If you say N here, the kernel will run on uni- and multiprocessor
431	  machines, but will use only one CPU of a multiprocessor machine. If
432	  you say Y here, the kernel will run on many, but not all,
433	  uniprocessor machines. On a uniprocessor machine, the kernel
434	  will run faster if you say N here.
435
436	  Note that if you say Y here and choose architecture "586" or
437	  "Pentium" under "Processor family", the kernel will not work on 486
438	  architectures. Similarly, multiprocessor kernels for the "PPro"
439	  architecture may not work on all Pentium based boards.
440
441	  People using multiprocessor machines who say Y here should also say
442	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
443	  Management" code will be disabled if you say Y here.
444
445	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
446	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
447	  <http://www.tldp.org/docs.html#howto>.
448
449	  If you don't know what to do here, say N.
450
451config X86_X2APIC
452	bool "Support x2apic"
453	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
454	help
455	  This enables x2apic support on CPUs that have this feature.
456
457	  This allows 32-bit apic IDs (so it can support very large systems),
458	  and accesses the local apic via MSRs not via mmio.
459
460	  Some Intel systems circa 2022 and later are locked into x2APIC mode
461	  and can not fall back to the legacy APIC modes if SGX or TDX are
462	  enabled in the BIOS. They will boot with very reduced functionality
463	  without enabling this option.
464
465	  If you don't know what to do here, say N.
466
467config X86_MPPARSE
468	bool "Enable MPS table" if ACPI
469	default y
470	depends on X86_LOCAL_APIC
471	help
472	  For old smp systems that do not have proper acpi support. Newer systems
473	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
474
475config GOLDFISH
476	def_bool y
477	depends on X86_GOLDFISH
478
479config X86_CPU_RESCTRL
480	bool "x86 CPU resource control support"
481	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
482	select KERNFS
483	select PROC_CPU_RESCTRL		if PROC_FS
484	help
485	  Enable x86 CPU resource control support.
486
487	  Provide support for the allocation and monitoring of system resources
488	  usage by the CPU.
489
490	  Intel calls this Intel Resource Director Technology
491	  (Intel(R) RDT). More information about RDT can be found in the
492	  Intel x86 Architecture Software Developer Manual.
493
494	  AMD calls this AMD Platform Quality of Service (AMD QoS).
495	  More information about AMD QoS can be found in the AMD64 Technology
496	  Platform Quality of Service Extensions manual.
497
498	  Say N if unsure.
499
500config X86_FRED
501	bool "Flexible Return and Event Delivery"
502	depends on X86_64
503	help
504	  When enabled, try to use Flexible Return and Event Delivery
505	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
506	  ring transitions and exception/interrupt handling if the
507	  system supports.
508
509if X86_32
510config X86_BIGSMP
511	bool "Support for big SMP systems with more than 8 CPUs"
512	depends on SMP
513	help
514	  This option is needed for the systems that have more than 8 CPUs.
515
516config X86_EXTENDED_PLATFORM
517	bool "Support for extended (non-PC) x86 platforms"
518	default y
519	help
520	  If you disable this option then the kernel will only support
521	  standard PC platforms. (which covers the vast majority of
522	  systems out there.)
523
524	  If you enable this option then you'll be able to select support
525	  for the following (non-PC) 32 bit x86 platforms:
526		Goldfish (Android emulator)
527		AMD Elan
528		RDC R-321x SoC
529		SGI 320/540 (Visual Workstation)
530		STA2X11-based (e.g. Northville)
531		Moorestown MID devices
532
533	  If you have one of these systems, or if you want to build a
534	  generic distribution kernel, say Y here - otherwise say N.
535endif # X86_32
536
537if X86_64
538config X86_EXTENDED_PLATFORM
539	bool "Support for extended (non-PC) x86 platforms"
540	default y
541	help
542	  If you disable this option then the kernel will only support
543	  standard PC platforms. (which covers the vast majority of
544	  systems out there.)
545
546	  If you enable this option then you'll be able to select support
547	  for the following (non-PC) 64 bit x86 platforms:
548		Numascale NumaChip
549		ScaleMP vSMP
550		SGI Ultraviolet
551
552	  If you have one of these systems, or if you want to build a
553	  generic distribution kernel, say Y here - otherwise say N.
554endif # X86_64
555# This is an alphabetically sorted list of 64 bit extended platforms
556# Please maintain the alphabetic order if and when there are additions
557config X86_NUMACHIP
558	bool "Numascale NumaChip"
559	depends on X86_64
560	depends on X86_EXTENDED_PLATFORM
561	depends on NUMA
562	depends on SMP
563	depends on X86_X2APIC
564	depends on PCI_MMCONFIG
565	help
566	  Adds support for Numascale NumaChip large-SMP systems. Needed to
567	  enable more than ~168 cores.
568	  If you don't have one of these, you should say N here.
569
570config X86_VSMP
571	bool "ScaleMP vSMP"
572	select HYPERVISOR_GUEST
573	select PARAVIRT
574	depends on X86_64 && PCI
575	depends on X86_EXTENDED_PLATFORM
576	depends on SMP
577	help
578	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
579	  supposed to run on these EM64T-based machines.  Only choose this option
580	  if you have one of these machines.
581
582config X86_UV
583	bool "SGI Ultraviolet"
584	depends on X86_64
585	depends on X86_EXTENDED_PLATFORM
586	depends on NUMA
587	depends on EFI
588	depends on KEXEC_CORE
589	depends on X86_X2APIC
590	depends on PCI
591	help
592	  This option is needed in order to support SGI Ultraviolet systems.
593	  If you don't have one of these, you should say N here.
594
595# Following is an alphabetically sorted list of 32 bit extended platforms
596# Please maintain the alphabetic order if and when there are additions
597
598config X86_GOLDFISH
599	bool "Goldfish (Virtual Platform)"
600	depends on X86_EXTENDED_PLATFORM
601	help
602	  Enable support for the Goldfish virtual platform used primarily
603	  for Android development. Unless you are building for the Android
604	  Goldfish emulator say N here.
605
606config X86_INTEL_CE
607	bool "CE4100 TV platform"
608	depends on PCI
609	depends on PCI_GODIRECT
610	depends on X86_IO_APIC
611	depends on X86_32
612	depends on X86_EXTENDED_PLATFORM
613	select X86_REBOOTFIXUPS
614	select OF
615	select OF_EARLY_FLATTREE
616	help
617	  Select for the Intel CE media processor (CE4100) SOC.
618	  This option compiles in support for the CE4100 SOC for settop
619	  boxes and media devices.
620
621config X86_INTEL_MID
622	bool "Intel MID platform support"
623	depends on X86_EXTENDED_PLATFORM
624	depends on X86_PLATFORM_DEVICES
625	depends on PCI
626	depends on X86_64 || (PCI_GOANY && X86_32)
627	depends on X86_IO_APIC
628	select I2C
629	select DW_APB_TIMER
630	select INTEL_SCU_PCI
631	help
632	  Select to build a kernel capable of supporting Intel MID (Mobile
633	  Internet Device) platform systems which do not have the PCI legacy
634	  interfaces. If you are building for a PC class system say N here.
635
636	  Intel MID platforms are based on an Intel processor and chipset which
637	  consume less power than most of the x86 derivatives.
638
639config X86_INTEL_QUARK
640	bool "Intel Quark platform support"
641	depends on X86_32
642	depends on X86_EXTENDED_PLATFORM
643	depends on X86_PLATFORM_DEVICES
644	depends on X86_TSC
645	depends on PCI
646	depends on PCI_GOANY
647	depends on X86_IO_APIC
648	select IOSF_MBI
649	select INTEL_IMR
650	select COMMON_CLK
651	help
652	  Select to include support for Quark X1000 SoC.
653	  Say Y here if you have a Quark based system such as the Arduino
654	  compatible Intel Galileo.
655
656config X86_INTEL_LPSS
657	bool "Intel Low Power Subsystem Support"
658	depends on X86 && ACPI && PCI
659	select COMMON_CLK
660	select PINCTRL
661	select IOSF_MBI
662	help
663	  Select to build support for Intel Low Power Subsystem such as
664	  found on Intel Lynxpoint PCH. Selecting this option enables
665	  things like clock tree (common clock framework) and pincontrol
666	  which are needed by the LPSS peripheral drivers.
667
668config X86_AMD_PLATFORM_DEVICE
669	bool "AMD ACPI2Platform devices support"
670	depends on ACPI
671	select COMMON_CLK
672	select PINCTRL
673	help
674	  Select to interpret AMD specific ACPI device to platform device
675	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
676	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
677	  implemented under PINCTRL subsystem.
678
679config IOSF_MBI
680	tristate "Intel SoC IOSF Sideband support for SoC platforms"
681	depends on PCI
682	help
683	  This option enables sideband register access support for Intel SoC
684	  platforms. On these platforms the IOSF sideband is used in lieu of
685	  MSR's for some register accesses, mostly but not limited to thermal
686	  and power. Drivers may query the availability of this device to
687	  determine if they need the sideband in order to work on these
688	  platforms. The sideband is available on the following SoC products.
689	  This list is not meant to be exclusive.
690	   - BayTrail
691	   - Braswell
692	   - Quark
693
694	  You should say Y if you are running a kernel on one of these SoC's.
695
696config IOSF_MBI_DEBUG
697	bool "Enable IOSF sideband access through debugfs"
698	depends on IOSF_MBI && DEBUG_FS
699	help
700	  Select this option to expose the IOSF sideband access registers (MCR,
701	  MDR, MCRX) through debugfs to write and read register information from
702	  different units on the SoC. This is most useful for obtaining device
703	  state information for debug and analysis. As this is a general access
704	  mechanism, users of this option would have specific knowledge of the
705	  device they want to access.
706
707	  If you don't require the option or are in doubt, say N.
708
709config X86_RDC321X
710	bool "RDC R-321x SoC"
711	depends on X86_32
712	depends on X86_EXTENDED_PLATFORM
713	select M486
714	select X86_REBOOTFIXUPS
715	help
716	  This option is needed for RDC R-321x system-on-chip, also known
717	  as R-8610-(G).
718	  If you don't have one of these chips, you should say N here.
719
720config X86_32_NON_STANDARD
721	bool "Support non-standard 32-bit SMP architectures"
722	depends on X86_32 && SMP
723	depends on X86_EXTENDED_PLATFORM
724	help
725	  This option compiles in the bigsmp and STA2X11 default
726	  subarchitectures.  It is intended for a generic binary
727	  kernel. If you select them all, kernel will probe it one by
728	  one and will fallback to default.
729
730# Alphabetically sorted list of Non standard 32 bit platforms
731
732config X86_SUPPORTS_MEMORY_FAILURE
733	def_bool y
734	# MCE code calls memory_failure():
735	depends on X86_MCE
736	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
737	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
738	depends on X86_64 || !SPARSEMEM
739	select ARCH_SUPPORTS_MEMORY_FAILURE
740
741config STA2X11
742	bool "STA2X11 Companion Chip Support"
743	depends on X86_32_NON_STANDARD && PCI
744	select SWIOTLB
745	select MFD_STA2X11
746	select GPIOLIB
747	help
748	  This adds support for boards based on the STA2X11 IO-Hub,
749	  a.k.a. "ConneXt". The chip is used in place of the standard
750	  PC chipset, so all "standard" peripherals are missing. If this
751	  option is selected the kernel will still be able to boot on
752	  standard PC machines.
753
754config X86_32_IRIS
755	tristate "Eurobraille/Iris poweroff module"
756	depends on X86_32
757	help
758	  The Iris machines from EuroBraille do not have APM or ACPI support
759	  to shut themselves down properly.  A special I/O sequence is
760	  needed to do so, which is what this module does at
761	  kernel shutdown.
762
763	  This is only for Iris machines from EuroBraille.
764
765	  If unused, say N.
766
767config SCHED_OMIT_FRAME_POINTER
768	def_bool y
769	prompt "Single-depth WCHAN output"
770	depends on X86
771	help
772	  Calculate simpler /proc/<PID>/wchan values. If this option
773	  is disabled then wchan values will recurse back to the
774	  caller function. This provides more accurate wchan values,
775	  at the expense of slightly more scheduling overhead.
776
777	  If in doubt, say "Y".
778
779menuconfig HYPERVISOR_GUEST
780	bool "Linux guest support"
781	help
782	  Say Y here to enable options for running Linux under various hyper-
783	  visors. This option enables basic hypervisor detection and platform
784	  setup.
785
786	  If you say N, all options in this submenu will be skipped and
787	  disabled, and Linux guest support won't be built in.
788
789if HYPERVISOR_GUEST
790
791config PARAVIRT
792	bool "Enable paravirtualization code"
793	depends on HAVE_STATIC_CALL
794	help
795	  This changes the kernel so it can modify itself when it is run
796	  under a hypervisor, potentially improving performance significantly
797	  over full virtualization.  However, when run without a hypervisor
798	  the kernel is theoretically slower and slightly larger.
799
800config PARAVIRT_XXL
801	bool
802
803config PARAVIRT_DEBUG
804	bool "paravirt-ops debugging"
805	depends on PARAVIRT && DEBUG_KERNEL
806	help
807	  Enable to debug paravirt_ops internals.  Specifically, BUG if
808	  a paravirt_op is missing when it is called.
809
810config PARAVIRT_SPINLOCKS
811	bool "Paravirtualization layer for spinlocks"
812	depends on PARAVIRT && SMP
813	help
814	  Paravirtualized spinlocks allow a pvops backend to replace the
815	  spinlock implementation with something virtualization-friendly
816	  (for example, block the virtual CPU rather than spinning).
817
818	  It has a minimal impact on native kernels and gives a nice performance
819	  benefit on paravirtualized KVM / Xen kernels.
820
821	  If you are unsure how to answer this question, answer Y.
822
823config X86_HV_CALLBACK_VECTOR
824	def_bool n
825
826source "arch/x86/xen/Kconfig"
827
828config KVM_GUEST
829	bool "KVM Guest support (including kvmclock)"
830	depends on PARAVIRT
831	select PARAVIRT_CLOCK
832	select ARCH_CPUIDLE_HALTPOLL
833	select X86_HV_CALLBACK_VECTOR
834	default y
835	help
836	  This option enables various optimizations for running under the KVM
837	  hypervisor. It includes a paravirtualized clock, so that instead
838	  of relying on a PIT (or probably other) emulation by the
839	  underlying device model, the host provides the guest with
840	  timing infrastructure such as time of day, and system time
841
842config ARCH_CPUIDLE_HALTPOLL
843	def_bool n
844	prompt "Disable host haltpoll when loading haltpoll driver"
845	help
846	  If virtualized under KVM, disable host haltpoll.
847
848config PVH
849	bool "Support for running PVH guests"
850	help
851	  This option enables the PVH entry point for guest virtual machines
852	  as specified in the x86/HVM direct boot ABI.
853
854config PARAVIRT_TIME_ACCOUNTING
855	bool "Paravirtual steal time accounting"
856	depends on PARAVIRT
857	help
858	  Select this option to enable fine granularity task steal time
859	  accounting. Time spent executing other tasks in parallel with
860	  the current vCPU is discounted from the vCPU power. To account for
861	  that, there can be a small performance impact.
862
863	  If in doubt, say N here.
864
865config PARAVIRT_CLOCK
866	bool
867
868config JAILHOUSE_GUEST
869	bool "Jailhouse non-root cell support"
870	depends on X86_64 && PCI
871	select X86_PM_TIMER
872	help
873	  This option allows to run Linux as guest in a Jailhouse non-root
874	  cell. You can leave this option disabled if you only want to start
875	  Jailhouse and run Linux afterwards in the root cell.
876
877config ACRN_GUEST
878	bool "ACRN Guest support"
879	depends on X86_64
880	select X86_HV_CALLBACK_VECTOR
881	help
882	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
883	  a flexible, lightweight reference open-source hypervisor, built with
884	  real-time and safety-criticality in mind. It is built for embedded
885	  IOT with small footprint and real-time features. More details can be
886	  found in https://projectacrn.org/.
887
888config INTEL_TDX_GUEST
889	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
890	depends on X86_64 && CPU_SUP_INTEL
891	depends on X86_X2APIC
892	depends on EFI_STUB
893	select ARCH_HAS_CC_PLATFORM
894	select X86_MEM_ENCRYPT
895	select X86_MCE
896	select UNACCEPTED_MEMORY
897	help
898	  Support running as a guest under Intel TDX.  Without this support,
899	  the guest kernel can not boot or run under TDX.
900	  TDX includes memory encryption and integrity capabilities
901	  which protect the confidentiality and integrity of guest
902	  memory contents and CPU state. TDX guests are protected from
903	  some attacks from the VMM.
904
905endif # HYPERVISOR_GUEST
906
907source "arch/x86/Kconfig.cpu"
908
909config HPET_TIMER
910	def_bool X86_64
911	prompt "HPET Timer Support" if X86_32
912	help
913	  Use the IA-PC HPET (High Precision Event Timer) to manage
914	  time in preference to the PIT and RTC, if a HPET is
915	  present.
916	  HPET is the next generation timer replacing legacy 8254s.
917	  The HPET provides a stable time base on SMP
918	  systems, unlike the TSC, but it is more expensive to access,
919	  as it is off-chip.  The interface used is documented
920	  in the HPET spec, revision 1.
921
922	  You can safely choose Y here.  However, HPET will only be
923	  activated if the platform and the BIOS support this feature.
924	  Otherwise the 8254 will be used for timing services.
925
926	  Choose N to continue using the legacy 8254 timer.
927
928config HPET_EMULATE_RTC
929	def_bool y
930	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
931
932# Mark as expert because too many people got it wrong.
933# The code disables itself when not needed.
934config DMI
935	default y
936	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
937	bool "Enable DMI scanning" if EXPERT
938	help
939	  Enabled scanning of DMI to identify machine quirks. Say Y
940	  here unless you have verified that your setup is not
941	  affected by entries in the DMI blacklist. Required by PNP
942	  BIOS code.
943
944config GART_IOMMU
945	bool "Old AMD GART IOMMU support"
946	select DMA_OPS
947	select IOMMU_HELPER
948	select SWIOTLB
949	depends on X86_64 && PCI && AMD_NB
950	help
951	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
952	  GART based hardware IOMMUs.
953
954	  The GART supports full DMA access for devices with 32-bit access
955	  limitations, on systems with more than 3 GB. This is usually needed
956	  for USB, sound, many IDE/SATA chipsets and some other devices.
957
958	  Newer systems typically have a modern AMD IOMMU, supported via
959	  the CONFIG_AMD_IOMMU=y config option.
960
961	  In normal configurations this driver is only active when needed:
962	  there's more than 3 GB of memory and the system contains a
963	  32-bit limited device.
964
965	  If unsure, say Y.
966
967config BOOT_VESA_SUPPORT
968	bool
969	help
970	  If true, at least one selected framebuffer driver can take advantage
971	  of VESA video modes set at an early boot stage via the vga= parameter.
972
973config MAXSMP
974	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
975	depends on X86_64 && SMP && DEBUG_KERNEL
976	select CPUMASK_OFFSTACK
977	help
978	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
979	  If unsure, say N.
980
981#
982# The maximum number of CPUs supported:
983#
984# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
985# and which can be configured interactively in the
986# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
987#
988# The ranges are different on 32-bit and 64-bit kernels, depending on
989# hardware capabilities and scalability features of the kernel.
990#
991# ( If MAXSMP is enabled we just use the highest possible value and disable
992#   interactive configuration. )
993#
994
995config NR_CPUS_RANGE_BEGIN
996	int
997	default NR_CPUS_RANGE_END if MAXSMP
998	default    1 if !SMP
999	default    2
1000
1001config NR_CPUS_RANGE_END
1002	int
1003	depends on X86_32
1004	default   64 if  SMP &&  X86_BIGSMP
1005	default    8 if  SMP && !X86_BIGSMP
1006	default    1 if !SMP
1007
1008config NR_CPUS_RANGE_END
1009	int
1010	depends on X86_64
1011	default 8192 if  SMP && CPUMASK_OFFSTACK
1012	default  512 if  SMP && !CPUMASK_OFFSTACK
1013	default    1 if !SMP
1014
1015config NR_CPUS_DEFAULT
1016	int
1017	depends on X86_32
1018	default   32 if  X86_BIGSMP
1019	default    8 if  SMP
1020	default    1 if !SMP
1021
1022config NR_CPUS_DEFAULT
1023	int
1024	depends on X86_64
1025	default 8192 if  MAXSMP
1026	default   64 if  SMP
1027	default    1 if !SMP
1028
1029config NR_CPUS
1030	int "Maximum number of CPUs" if SMP && !MAXSMP
1031	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1032	default NR_CPUS_DEFAULT
1033	help
1034	  This allows you to specify the maximum number of CPUs which this
1035	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1036	  supported value is 8192, otherwise the maximum value is 512.  The
1037	  minimum value which makes sense is 2.
1038
1039	  This is purely to save memory: each supported CPU adds about 8KB
1040	  to the kernel image.
1041
1042config SCHED_CLUSTER
1043	bool "Cluster scheduler support"
1044	depends on SMP
1045	default y
1046	help
1047	  Cluster scheduler support improves the CPU scheduler's decision
1048	  making when dealing with machines that have clusters of CPUs.
1049	  Cluster usually means a couple of CPUs which are placed closely
1050	  by sharing mid-level caches, last-level cache tags or internal
1051	  busses.
1052
1053config SCHED_SMT
1054	def_bool y if SMP
1055
1056config SCHED_MC
1057	def_bool y
1058	prompt "Multi-core scheduler support"
1059	depends on SMP
1060	help
1061	  Multi-core scheduler support improves the CPU scheduler's decision
1062	  making when dealing with multi-core CPU chips at a cost of slightly
1063	  increased overhead in some places. If unsure say N here.
1064
1065config SCHED_MC_PRIO
1066	bool "CPU core priorities scheduler support"
1067	depends on SCHED_MC
1068	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1069	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1070	select CPU_FREQ
1071	default y
1072	help
1073	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1074	  core ordering determined at manufacturing time, which allows
1075	  certain cores to reach higher turbo frequencies (when running
1076	  single threaded workloads) than others.
1077
1078	  Enabling this kernel feature teaches the scheduler about
1079	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1080	  scheduler's CPU selection logic accordingly, so that higher
1081	  overall system performance can be achieved.
1082
1083	  This feature will have no effect on CPUs without this feature.
1084
1085	  If unsure say Y here.
1086
1087config UP_LATE_INIT
1088	def_bool y
1089	depends on !SMP && X86_LOCAL_APIC
1090
1091config X86_UP_APIC
1092	bool "Local APIC support on uniprocessors" if !PCI_MSI
1093	default PCI_MSI
1094	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1095	help
1096	  A local APIC (Advanced Programmable Interrupt Controller) is an
1097	  integrated interrupt controller in the CPU. If you have a single-CPU
1098	  system which has a processor with a local APIC, you can say Y here to
1099	  enable and use it. If you say Y here even though your machine doesn't
1100	  have a local APIC, then the kernel will still run with no slowdown at
1101	  all. The local APIC supports CPU-generated self-interrupts (timer,
1102	  performance counters), and the NMI watchdog which detects hard
1103	  lockups.
1104
1105config X86_UP_IOAPIC
1106	bool "IO-APIC support on uniprocessors"
1107	depends on X86_UP_APIC
1108	help
1109	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1110	  SMP-capable replacement for PC-style interrupt controllers. Most
1111	  SMP systems and many recent uniprocessor systems have one.
1112
1113	  If you have a single-CPU system with an IO-APIC, you can say Y here
1114	  to use it. If you say Y here even though your machine doesn't have
1115	  an IO-APIC, then the kernel will still run with no slowdown at all.
1116
1117config X86_LOCAL_APIC
1118	def_bool y
1119	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1120	select IRQ_DOMAIN_HIERARCHY
1121
1122config X86_IO_APIC
1123	def_bool y
1124	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1125
1126config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1127	bool "Reroute for broken boot IRQs"
1128	depends on X86_IO_APIC
1129	help
1130	  This option enables a workaround that fixes a source of
1131	  spurious interrupts. This is recommended when threaded
1132	  interrupt handling is used on systems where the generation of
1133	  superfluous "boot interrupts" cannot be disabled.
1134
1135	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1136	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1137	  kernel does during interrupt handling). On chipsets where this
1138	  boot IRQ generation cannot be disabled, this workaround keeps
1139	  the original IRQ line masked so that only the equivalent "boot
1140	  IRQ" is delivered to the CPUs. The workaround also tells the
1141	  kernel to set up the IRQ handler on the boot IRQ line. In this
1142	  way only one interrupt is delivered to the kernel. Otherwise
1143	  the spurious second interrupt may cause the kernel to bring
1144	  down (vital) interrupt lines.
1145
1146	  Only affects "broken" chipsets. Interrupt sharing may be
1147	  increased on these systems.
1148
1149config X86_MCE
1150	bool "Machine Check / overheating reporting"
1151	select GENERIC_ALLOCATOR
1152	default y
1153	help
1154	  Machine Check support allows the processor to notify the
1155	  kernel if it detects a problem (e.g. overheating, data corruption).
1156	  The action the kernel takes depends on the severity of the problem,
1157	  ranging from warning messages to halting the machine.
1158
1159config X86_MCELOG_LEGACY
1160	bool "Support for deprecated /dev/mcelog character device"
1161	depends on X86_MCE
1162	help
1163	  Enable support for /dev/mcelog which is needed by the old mcelog
1164	  userspace logging daemon. Consider switching to the new generation
1165	  rasdaemon solution.
1166
1167config X86_MCE_INTEL
1168	def_bool y
1169	prompt "Intel MCE features"
1170	depends on X86_MCE && X86_LOCAL_APIC
1171	help
1172	  Additional support for intel specific MCE features such as
1173	  the thermal monitor.
1174
1175config X86_MCE_AMD
1176	def_bool y
1177	prompt "AMD MCE features"
1178	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1179	help
1180	  Additional support for AMD specific MCE features such as
1181	  the DRAM Error Threshold.
1182
1183config X86_ANCIENT_MCE
1184	bool "Support for old Pentium 5 / WinChip machine checks"
1185	depends on X86_32 && X86_MCE
1186	help
1187	  Include support for machine check handling on old Pentium 5 or WinChip
1188	  systems. These typically need to be enabled explicitly on the command
1189	  line.
1190
1191config X86_MCE_THRESHOLD
1192	depends on X86_MCE_AMD || X86_MCE_INTEL
1193	def_bool y
1194
1195config X86_MCE_INJECT
1196	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1197	tristate "Machine check injector support"
1198	help
1199	  Provide support for injecting machine checks for testing purposes.
1200	  If you don't know what a machine check is and you don't do kernel
1201	  QA it is safe to say n.
1202
1203source "arch/x86/events/Kconfig"
1204
1205config X86_LEGACY_VM86
1206	bool "Legacy VM86 support"
1207	depends on X86_32
1208	help
1209	  This option allows user programs to put the CPU into V8086
1210	  mode, which is an 80286-era approximation of 16-bit real mode.
1211
1212	  Some very old versions of X and/or vbetool require this option
1213	  for user mode setting.  Similarly, DOSEMU will use it if
1214	  available to accelerate real mode DOS programs.  However, any
1215	  recent version of DOSEMU, X, or vbetool should be fully
1216	  functional even without kernel VM86 support, as they will all
1217	  fall back to software emulation. Nevertheless, if you are using
1218	  a 16-bit DOS program where 16-bit performance matters, vm86
1219	  mode might be faster than emulation and you might want to
1220	  enable this option.
1221
1222	  Note that any app that works on a 64-bit kernel is unlikely to
1223	  need this option, as 64-bit kernels don't, and can't, support
1224	  V8086 mode. This option is also unrelated to 16-bit protected
1225	  mode and is not needed to run most 16-bit programs under Wine.
1226
1227	  Enabling this option increases the complexity of the kernel
1228	  and slows down exception handling a tiny bit.
1229
1230	  If unsure, say N here.
1231
1232config VM86
1233	bool
1234	default X86_LEGACY_VM86
1235
1236config X86_16BIT
1237	bool "Enable support for 16-bit segments" if EXPERT
1238	default y
1239	depends on MODIFY_LDT_SYSCALL
1240	help
1241	  This option is required by programs like Wine to run 16-bit
1242	  protected mode legacy code on x86 processors.  Disabling
1243	  this option saves about 300 bytes on i386, or around 6K text
1244	  plus 16K runtime memory on x86-64,
1245
1246config X86_ESPFIX32
1247	def_bool y
1248	depends on X86_16BIT && X86_32
1249
1250config X86_ESPFIX64
1251	def_bool y
1252	depends on X86_16BIT && X86_64
1253
1254config X86_VSYSCALL_EMULATION
1255	bool "Enable vsyscall emulation" if EXPERT
1256	default y
1257	depends on X86_64
1258	help
1259	  This enables emulation of the legacy vsyscall page.  Disabling
1260	  it is roughly equivalent to booting with vsyscall=none, except
1261	  that it will also disable the helpful warning if a program
1262	  tries to use a vsyscall.  With this option set to N, offending
1263	  programs will just segfault, citing addresses of the form
1264	  0xffffffffff600?00.
1265
1266	  This option is required by many programs built before 2013, and
1267	  care should be used even with newer programs if set to N.
1268
1269	  Disabling this option saves about 7K of kernel size and
1270	  possibly 4K of additional runtime pagetable memory.
1271
1272config X86_IOPL_IOPERM
1273	bool "IOPERM and IOPL Emulation"
1274	default y
1275	help
1276	  This enables the ioperm() and iopl() syscalls which are necessary
1277	  for legacy applications.
1278
1279	  Legacy IOPL support is an overbroad mechanism which allows user
1280	  space aside of accessing all 65536 I/O ports also to disable
1281	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1282	  capabilities and permission from potentially active security
1283	  modules.
1284
1285	  The emulation restricts the functionality of the syscall to
1286	  only allowing the full range I/O port access, but prevents the
1287	  ability to disable interrupts from user space which would be
1288	  granted if the hardware IOPL mechanism would be used.
1289
1290config TOSHIBA
1291	tristate "Toshiba Laptop support"
1292	depends on X86_32
1293	help
1294	  This adds a driver to safely access the System Management Mode of
1295	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1296	  not work on models with a Phoenix BIOS. The System Management Mode
1297	  is used to set the BIOS and power saving options on Toshiba portables.
1298
1299	  For information on utilities to make use of this driver see the
1300	  Toshiba Linux utilities web site at:
1301	  <http://www.buzzard.org.uk/toshiba/>.
1302
1303	  Say Y if you intend to run this kernel on a Toshiba portable.
1304	  Say N otherwise.
1305
1306config X86_REBOOTFIXUPS
1307	bool "Enable X86 board specific fixups for reboot"
1308	depends on X86_32
1309	help
1310	  This enables chipset and/or board specific fixups to be done
1311	  in order to get reboot to work correctly. This is only needed on
1312	  some combinations of hardware and BIOS. The symptom, for which
1313	  this config is intended, is when reboot ends with a stalled/hung
1314	  system.
1315
1316	  Currently, the only fixup is for the Geode machines using
1317	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1318
1319	  Say Y if you want to enable the fixup. Currently, it's safe to
1320	  enable this option even if you don't need it.
1321	  Say N otherwise.
1322
1323config MICROCODE
1324	def_bool y
1325	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1326
1327config MICROCODE_INITRD32
1328	def_bool y
1329	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1330
1331config MICROCODE_LATE_LOADING
1332	bool "Late microcode loading (DANGEROUS)"
1333	default n
1334	depends on MICROCODE && SMP
1335	help
1336	  Loading microcode late, when the system is up and executing instructions
1337	  is a tricky business and should be avoided if possible. Just the sequence
1338	  of synchronizing all cores and SMT threads is one fragile dance which does
1339	  not guarantee that cores might not softlock after the loading. Therefore,
1340	  use this at your own risk. Late loading taints the kernel unless the
1341	  microcode header indicates that it is safe for late loading via the
1342	  minimal revision check. This minimal revision check can be enforced on
1343	  the kernel command line with "microcode.minrev=Y".
1344
1345config MICROCODE_LATE_FORCE_MINREV
1346	bool "Enforce late microcode loading minimal revision check"
1347	default n
1348	depends on MICROCODE_LATE_LOADING
1349	help
1350	  To prevent that users load microcode late which modifies already
1351	  in use features, newer microcode patches have a minimum revision field
1352	  in the microcode header, which tells the kernel which minimum
1353	  revision must be active in the CPU to safely load that new microcode
1354	  late into the running system. If disabled the check will not
1355	  be enforced but the kernel will be tainted when the minimal
1356	  revision check fails.
1357
1358	  This minimal revision check can also be controlled via the
1359	  "microcode.minrev" parameter on the kernel command line.
1360
1361	  If unsure say Y.
1362
1363config X86_MSR
1364	tristate "/dev/cpu/*/msr - Model-specific register support"
1365	help
1366	  This device gives privileged processes access to the x86
1367	  Model-Specific Registers (MSRs).  It is a character device with
1368	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1369	  MSR accesses are directed to a specific CPU on multi-processor
1370	  systems.
1371
1372config X86_CPUID
1373	tristate "/dev/cpu/*/cpuid - CPU information support"
1374	help
1375	  This device gives processes access to the x86 CPUID instruction to
1376	  be executed on a specific processor.  It is a character device
1377	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1378	  /dev/cpu/31/cpuid.
1379
1380choice
1381	prompt "High Memory Support"
1382	default HIGHMEM4G
1383	depends on X86_32
1384
1385config NOHIGHMEM
1386	bool "off"
1387	help
1388	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1389	  However, the address space of 32-bit x86 processors is only 4
1390	  Gigabytes large. That means that, if you have a large amount of
1391	  physical memory, not all of it can be "permanently mapped" by the
1392	  kernel. The physical memory that's not permanently mapped is called
1393	  "high memory".
1394
1395	  If you are compiling a kernel which will never run on a machine with
1396	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1397	  choice and suitable for most users). This will result in a "3GB/1GB"
1398	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1399	  space and the remaining part of the 4GB virtual memory space is used
1400	  by the kernel to permanently map as much physical memory as
1401	  possible.
1402
1403	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1404	  answer "4GB" here.
1405
1406	  If more than 4 Gigabytes is used then answer "64GB" here. This
1407	  selection turns Intel PAE (Physical Address Extension) mode on.
1408	  PAE implements 3-level paging on IA32 processors. PAE is fully
1409	  supported by Linux, PAE mode is implemented on all recent Intel
1410	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1411	  then the kernel will not boot on CPUs that don't support PAE!
1412
1413	  The actual amount of total physical memory will either be
1414	  auto detected or can be forced by using a kernel command line option
1415	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1416	  your boot loader (lilo or loadlin) about how to pass options to the
1417	  kernel at boot time.)
1418
1419	  If unsure, say "off".
1420
1421config HIGHMEM4G
1422	bool "4GB"
1423	help
1424	  Select this if you have a 32-bit processor and between 1 and 4
1425	  gigabytes of physical RAM.
1426
1427config HIGHMEM64G
1428	bool "64GB"
1429	depends on X86_HAVE_PAE
1430	select X86_PAE
1431	help
1432	  Select this if you have a 32-bit processor and more than 4
1433	  gigabytes of physical RAM.
1434
1435endchoice
1436
1437choice
1438	prompt "Memory split" if EXPERT
1439	default VMSPLIT_3G
1440	depends on X86_32
1441	help
1442	  Select the desired split between kernel and user memory.
1443
1444	  If the address range available to the kernel is less than the
1445	  physical memory installed, the remaining memory will be available
1446	  as "high memory". Accessing high memory is a little more costly
1447	  than low memory, as it needs to be mapped into the kernel first.
1448	  Note that increasing the kernel address space limits the range
1449	  available to user programs, making the address space there
1450	  tighter.  Selecting anything other than the default 3G/1G split
1451	  will also likely make your kernel incompatible with binary-only
1452	  kernel modules.
1453
1454	  If you are not absolutely sure what you are doing, leave this
1455	  option alone!
1456
1457	config VMSPLIT_3G
1458		bool "3G/1G user/kernel split"
1459	config VMSPLIT_3G_OPT
1460		depends on !X86_PAE
1461		bool "3G/1G user/kernel split (for full 1G low memory)"
1462	config VMSPLIT_2G
1463		bool "2G/2G user/kernel split"
1464	config VMSPLIT_2G_OPT
1465		depends on !X86_PAE
1466		bool "2G/2G user/kernel split (for full 2G low memory)"
1467	config VMSPLIT_1G
1468		bool "1G/3G user/kernel split"
1469endchoice
1470
1471config PAGE_OFFSET
1472	hex
1473	default 0xB0000000 if VMSPLIT_3G_OPT
1474	default 0x80000000 if VMSPLIT_2G
1475	default 0x78000000 if VMSPLIT_2G_OPT
1476	default 0x40000000 if VMSPLIT_1G
1477	default 0xC0000000
1478	depends on X86_32
1479
1480config HIGHMEM
1481	def_bool y
1482	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1483
1484config X86_PAE
1485	bool "PAE (Physical Address Extension) Support"
1486	depends on X86_32 && X86_HAVE_PAE
1487	select PHYS_ADDR_T_64BIT
1488	select SWIOTLB
1489	help
1490	  PAE is required for NX support, and furthermore enables
1491	  larger swapspace support for non-overcommit purposes. It
1492	  has the cost of more pagetable lookup overhead, and also
1493	  consumes more pagetable space per process.
1494
1495config X86_5LEVEL
1496	bool "Enable 5-level page tables support"
1497	default y
1498	select DYNAMIC_MEMORY_LAYOUT
1499	select SPARSEMEM_VMEMMAP
1500	depends on X86_64
1501	help
1502	  5-level paging enables access to larger address space:
1503	  up to 128 PiB of virtual address space and 4 PiB of
1504	  physical address space.
1505
1506	  It will be supported by future Intel CPUs.
1507
1508	  A kernel with the option enabled can be booted on machines that
1509	  support 4- or 5-level paging.
1510
1511	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1512	  information.
1513
1514	  Say N if unsure.
1515
1516config X86_DIRECT_GBPAGES
1517	def_bool y
1518	depends on X86_64
1519	help
1520	  Certain kernel features effectively disable kernel
1521	  linear 1 GB mappings (even if the CPU otherwise
1522	  supports them), so don't confuse the user by printing
1523	  that we have them enabled.
1524
1525config X86_CPA_STATISTICS
1526	bool "Enable statistic for Change Page Attribute"
1527	depends on DEBUG_FS
1528	help
1529	  Expose statistics about the Change Page Attribute mechanism, which
1530	  helps to determine the effectiveness of preserving large and huge
1531	  page mappings when mapping protections are changed.
1532
1533config X86_MEM_ENCRYPT
1534	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1535	select DYNAMIC_PHYSICAL_MASK
1536	def_bool n
1537
1538config AMD_MEM_ENCRYPT
1539	bool "AMD Secure Memory Encryption (SME) support"
1540	depends on X86_64 && CPU_SUP_AMD
1541	depends on EFI_STUB
1542	select DMA_COHERENT_POOL
1543	select ARCH_USE_MEMREMAP_PROT
1544	select INSTRUCTION_DECODER
1545	select ARCH_HAS_CC_PLATFORM
1546	select X86_MEM_ENCRYPT
1547	select UNACCEPTED_MEMORY
1548	help
1549	  Say yes to enable support for the encryption of system memory.
1550	  This requires an AMD processor that supports Secure Memory
1551	  Encryption (SME).
1552
1553# Common NUMA Features
1554config NUMA
1555	bool "NUMA Memory Allocation and Scheduler Support"
1556	depends on SMP
1557	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1558	default y if X86_BIGSMP
1559	select USE_PERCPU_NUMA_NODE_ID
1560	select OF_NUMA if OF
1561	help
1562	  Enable NUMA (Non-Uniform Memory Access) support.
1563
1564	  The kernel will try to allocate memory used by a CPU on the
1565	  local memory controller of the CPU and add some more
1566	  NUMA awareness to the kernel.
1567
1568	  For 64-bit this is recommended if the system is Intel Core i7
1569	  (or later), AMD Opteron, or EM64T NUMA.
1570
1571	  For 32-bit this is only needed if you boot a 32-bit
1572	  kernel on a 64-bit NUMA platform.
1573
1574	  Otherwise, you should say N.
1575
1576config AMD_NUMA
1577	def_bool y
1578	prompt "Old style AMD Opteron NUMA detection"
1579	depends on X86_64 && NUMA && PCI
1580	help
1581	  Enable AMD NUMA node topology detection.  You should say Y here if
1582	  you have a multi processor AMD system. This uses an old method to
1583	  read the NUMA configuration directly from the builtin Northbridge
1584	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1585	  which also takes priority if both are compiled in.
1586
1587config X86_64_ACPI_NUMA
1588	def_bool y
1589	prompt "ACPI NUMA detection"
1590	depends on X86_64 && NUMA && ACPI && PCI
1591	select ACPI_NUMA
1592	help
1593	  Enable ACPI SRAT based node topology detection.
1594
1595config NUMA_EMU
1596	bool "NUMA emulation"
1597	depends on NUMA
1598	help
1599	  Enable NUMA emulation. A flat machine will be split
1600	  into virtual nodes when booted with "numa=fake=N", where N is the
1601	  number of nodes. This is only useful for debugging.
1602
1603config NODES_SHIFT
1604	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1605	range 1 10
1606	default "10" if MAXSMP
1607	default "6" if X86_64
1608	default "3"
1609	depends on NUMA
1610	help
1611	  Specify the maximum number of NUMA Nodes available on the target
1612	  system.  Increases memory reserved to accommodate various tables.
1613
1614config ARCH_FLATMEM_ENABLE
1615	def_bool y
1616	depends on X86_32 && !NUMA
1617
1618config ARCH_SPARSEMEM_ENABLE
1619	def_bool y
1620	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1621	select SPARSEMEM_STATIC if X86_32
1622	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1623
1624config ARCH_SPARSEMEM_DEFAULT
1625	def_bool X86_64 || (NUMA && X86_32)
1626
1627config ARCH_SELECT_MEMORY_MODEL
1628	def_bool y
1629	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1630
1631config ARCH_MEMORY_PROBE
1632	bool "Enable sysfs memory/probe interface"
1633	depends on MEMORY_HOTPLUG
1634	help
1635	  This option enables a sysfs memory/probe interface for testing.
1636	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1637	  If you are unsure how to answer this question, answer N.
1638
1639config ARCH_PROC_KCORE_TEXT
1640	def_bool y
1641	depends on X86_64 && PROC_KCORE
1642
1643config ILLEGAL_POINTER_VALUE
1644	hex
1645	default 0 if X86_32
1646	default 0xdead000000000000 if X86_64
1647
1648config X86_PMEM_LEGACY_DEVICE
1649	bool
1650
1651config X86_PMEM_LEGACY
1652	tristate "Support non-standard NVDIMMs and ADR protected memory"
1653	depends on PHYS_ADDR_T_64BIT
1654	depends on BLK_DEV
1655	select X86_PMEM_LEGACY_DEVICE
1656	select NUMA_KEEP_MEMINFO if NUMA
1657	select LIBNVDIMM
1658	help
1659	  Treat memory marked using the non-standard e820 type of 12 as used
1660	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1661	  The kernel will offer these regions to the 'pmem' driver so
1662	  they can be used for persistent storage.
1663
1664	  Say Y if unsure.
1665
1666config HIGHPTE
1667	bool "Allocate 3rd-level pagetables from highmem"
1668	depends on HIGHMEM
1669	help
1670	  The VM uses one page table entry for each page of physical memory.
1671	  For systems with a lot of RAM, this can be wasteful of precious
1672	  low memory.  Setting this option will put user-space page table
1673	  entries in high memory.
1674
1675config X86_CHECK_BIOS_CORRUPTION
1676	bool "Check for low memory corruption"
1677	help
1678	  Periodically check for memory corruption in low memory, which
1679	  is suspected to be caused by BIOS.  Even when enabled in the
1680	  configuration, it is disabled at runtime.  Enable it by
1681	  setting "memory_corruption_check=1" on the kernel command
1682	  line.  By default it scans the low 64k of memory every 60
1683	  seconds; see the memory_corruption_check_size and
1684	  memory_corruption_check_period parameters in
1685	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1686
1687	  When enabled with the default parameters, this option has
1688	  almost no overhead, as it reserves a relatively small amount
1689	  of memory and scans it infrequently.  It both detects corruption
1690	  and prevents it from affecting the running system.
1691
1692	  It is, however, intended as a diagnostic tool; if repeatable
1693	  BIOS-originated corruption always affects the same memory,
1694	  you can use memmap= to prevent the kernel from using that
1695	  memory.
1696
1697config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1698	bool "Set the default setting of memory_corruption_check"
1699	depends on X86_CHECK_BIOS_CORRUPTION
1700	default y
1701	help
1702	  Set whether the default state of memory_corruption_check is
1703	  on or off.
1704
1705config MATH_EMULATION
1706	bool
1707	depends on MODIFY_LDT_SYSCALL
1708	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1709	help
1710	  Linux can emulate a math coprocessor (used for floating point
1711	  operations) if you don't have one. 486DX and Pentium processors have
1712	  a math coprocessor built in, 486SX and 386 do not, unless you added
1713	  a 487DX or 387, respectively. (The messages during boot time can
1714	  give you some hints here ["man dmesg"].) Everyone needs either a
1715	  coprocessor or this emulation.
1716
1717	  If you don't have a math coprocessor, you need to say Y here; if you
1718	  say Y here even though you have a coprocessor, the coprocessor will
1719	  be used nevertheless. (This behavior can be changed with the kernel
1720	  command line option "no387", which comes handy if your coprocessor
1721	  is broken. Try "man bootparam" or see the documentation of your boot
1722	  loader (lilo or loadlin) about how to pass options to the kernel at
1723	  boot time.) This means that it is a good idea to say Y here if you
1724	  intend to use this kernel on different machines.
1725
1726	  More information about the internals of the Linux math coprocessor
1727	  emulation can be found in <file:arch/x86/math-emu/README>.
1728
1729	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1730	  kernel, it won't hurt.
1731
1732config MTRR
1733	def_bool y
1734	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1735	help
1736	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1737	  the Memory Type Range Registers (MTRRs) may be used to control
1738	  processor access to memory ranges. This is most useful if you have
1739	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1740	  allows bus write transfers to be combined into a larger transfer
1741	  before bursting over the PCI/AGP bus. This can increase performance
1742	  of image write operations 2.5 times or more. Saying Y here creates a
1743	  /proc/mtrr file which may be used to manipulate your processor's
1744	  MTRRs. Typically the X server should use this.
1745
1746	  This code has a reasonably generic interface so that similar
1747	  control registers on other processors can be easily supported
1748	  as well:
1749
1750	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1751	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1752	  these, the ARRs are used to emulate the MTRRs.
1753	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1754	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1755	  write-combining. All of these processors are supported by this code
1756	  and it makes sense to say Y here if you have one of them.
1757
1758	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1759	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1760	  can lead to all sorts of problems, so it's good to say Y here.
1761
1762	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1763	  just add about 9 KB to your kernel.
1764
1765	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1766
1767config MTRR_SANITIZER
1768	def_bool y
1769	prompt "MTRR cleanup support"
1770	depends on MTRR
1771	help
1772	  Convert MTRR layout from continuous to discrete, so X drivers can
1773	  add writeback entries.
1774
1775	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1776	  The largest mtrr entry size for a continuous block can be set with
1777	  mtrr_chunk_size.
1778
1779	  If unsure, say Y.
1780
1781config MTRR_SANITIZER_ENABLE_DEFAULT
1782	int "MTRR cleanup enable value (0-1)"
1783	range 0 1
1784	default "0"
1785	depends on MTRR_SANITIZER
1786	help
1787	  Enable mtrr cleanup default value
1788
1789config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1790	int "MTRR cleanup spare reg num (0-7)"
1791	range 0 7
1792	default "1"
1793	depends on MTRR_SANITIZER
1794	help
1795	  mtrr cleanup spare entries default, it can be changed via
1796	  mtrr_spare_reg_nr=N on the kernel command line.
1797
1798config X86_PAT
1799	def_bool y
1800	prompt "x86 PAT support" if EXPERT
1801	depends on MTRR
1802	help
1803	  Use PAT attributes to setup page level cache control.
1804
1805	  PATs are the modern equivalents of MTRRs and are much more
1806	  flexible than MTRRs.
1807
1808	  Say N here if you see bootup problems (boot crash, boot hang,
1809	  spontaneous reboots) or a non-working video driver.
1810
1811	  If unsure, say Y.
1812
1813config ARCH_USES_PG_UNCACHED
1814	def_bool y
1815	depends on X86_PAT
1816
1817config X86_UMIP
1818	def_bool y
1819	prompt "User Mode Instruction Prevention" if EXPERT
1820	help
1821	  User Mode Instruction Prevention (UMIP) is a security feature in
1822	  some x86 processors. If enabled, a general protection fault is
1823	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1824	  executed in user mode. These instructions unnecessarily expose
1825	  information about the hardware state.
1826
1827	  The vast majority of applications do not use these instructions.
1828	  For the very few that do, software emulation is provided in
1829	  specific cases in protected and virtual-8086 modes. Emulated
1830	  results are dummy.
1831
1832config CC_HAS_IBT
1833	# GCC >= 9 and binutils >= 2.29
1834	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1835	# Clang/LLVM >= 14
1836	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1837	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1838	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1839		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1840		  $(as-instr,endbr64)
1841
1842config X86_CET
1843	def_bool n
1844	help
1845	  CET features configured (Shadow stack or IBT)
1846
1847config X86_KERNEL_IBT
1848	prompt "Indirect Branch Tracking"
1849	def_bool y
1850	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1851	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1852	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1853	select OBJTOOL
1854	select X86_CET
1855	help
1856	  Build the kernel with support for Indirect Branch Tracking, a
1857	  hardware support course-grain forward-edge Control Flow Integrity
1858	  protection. It enforces that all indirect calls must land on
1859	  an ENDBR instruction, as such, the compiler will instrument the
1860	  code with them to make this happen.
1861
1862	  In addition to building the kernel with IBT, seal all functions that
1863	  are not indirect call targets, avoiding them ever becoming one.
1864
1865	  This requires LTO like objtool runs and will slow down the build. It
1866	  does significantly reduce the number of ENDBR instructions in the
1867	  kernel image.
1868
1869config X86_INTEL_MEMORY_PROTECTION_KEYS
1870	prompt "Memory Protection Keys"
1871	def_bool y
1872	# Note: only available in 64-bit mode
1873	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1874	select ARCH_USES_HIGH_VMA_FLAGS
1875	select ARCH_HAS_PKEYS
1876	help
1877	  Memory Protection Keys provides a mechanism for enforcing
1878	  page-based protections, but without requiring modification of the
1879	  page tables when an application changes protection domains.
1880
1881	  For details, see Documentation/core-api/protection-keys.rst
1882
1883	  If unsure, say y.
1884
1885choice
1886	prompt "TSX enable mode"
1887	depends on CPU_SUP_INTEL
1888	default X86_INTEL_TSX_MODE_OFF
1889	help
1890	  Intel's TSX (Transactional Synchronization Extensions) feature
1891	  allows to optimize locking protocols through lock elision which
1892	  can lead to a noticeable performance boost.
1893
1894	  On the other hand it has been shown that TSX can be exploited
1895	  to form side channel attacks (e.g. TAA) and chances are there
1896	  will be more of those attacks discovered in the future.
1897
1898	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1899	  might override this decision by tsx=on the command line parameter.
1900	  Even with TSX enabled, the kernel will attempt to enable the best
1901	  possible TAA mitigation setting depending on the microcode available
1902	  for the particular machine.
1903
1904	  This option allows to set the default tsx mode between tsx=on, =off
1905	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1906	  details.
1907
1908	  Say off if not sure, auto if TSX is in use but it should be used on safe
1909	  platforms or on if TSX is in use and the security aspect of tsx is not
1910	  relevant.
1911
1912config X86_INTEL_TSX_MODE_OFF
1913	bool "off"
1914	help
1915	  TSX is disabled if possible - equals to tsx=off command line parameter.
1916
1917config X86_INTEL_TSX_MODE_ON
1918	bool "on"
1919	help
1920	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1921	  line parameter.
1922
1923config X86_INTEL_TSX_MODE_AUTO
1924	bool "auto"
1925	help
1926	  TSX is enabled on TSX capable HW that is believed to be safe against
1927	  side channel attacks- equals the tsx=auto command line parameter.
1928endchoice
1929
1930config X86_SGX
1931	bool "Software Guard eXtensions (SGX)"
1932	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1933	depends on CRYPTO=y
1934	depends on CRYPTO_SHA256=y
1935	select MMU_NOTIFIER
1936	select NUMA_KEEP_MEMINFO if NUMA
1937	select XARRAY_MULTI
1938	help
1939	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1940	  that can be used by applications to set aside private regions of code
1941	  and data, referred to as enclaves. An enclave's private memory can
1942	  only be accessed by code running within the enclave. Accesses from
1943	  outside the enclave, including other enclaves, are disallowed by
1944	  hardware.
1945
1946	  If unsure, say N.
1947
1948config X86_USER_SHADOW_STACK
1949	bool "X86 userspace shadow stack"
1950	depends on AS_WRUSS
1951	depends on X86_64
1952	select ARCH_USES_HIGH_VMA_FLAGS
1953	select X86_CET
1954	help
1955	  Shadow stack protection is a hardware feature that detects function
1956	  return address corruption.  This helps mitigate ROP attacks.
1957	  Applications must be enabled to use it, and old userspace does not
1958	  get protection "for free".
1959
1960	  CPUs supporting shadow stacks were first released in 2020.
1961
1962	  See Documentation/arch/x86/shstk.rst for more information.
1963
1964	  If unsure, say N.
1965
1966config INTEL_TDX_HOST
1967	bool "Intel Trust Domain Extensions (TDX) host support"
1968	depends on CPU_SUP_INTEL
1969	depends on X86_64
1970	depends on KVM_INTEL
1971	depends on X86_X2APIC
1972	select ARCH_KEEP_MEMBLOCK
1973	depends on CONTIG_ALLOC
1974	depends on !KEXEC_CORE
1975	depends on X86_MCE
1976	help
1977	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1978	  host and certain physical attacks.  This option enables necessary TDX
1979	  support in the host kernel to run confidential VMs.
1980
1981	  If unsure, say N.
1982
1983config EFI
1984	bool "EFI runtime service support"
1985	depends on ACPI
1986	select UCS2_STRING
1987	select EFI_RUNTIME_WRAPPERS
1988	select ARCH_USE_MEMREMAP_PROT
1989	select EFI_RUNTIME_MAP if KEXEC_CORE
1990	help
1991	  This enables the kernel to use EFI runtime services that are
1992	  available (such as the EFI variable services).
1993
1994	  This option is only useful on systems that have EFI firmware.
1995	  In addition, you should use the latest ELILO loader available
1996	  at <http://elilo.sourceforge.net> in order to take advantage
1997	  of EFI runtime services. However, even with this option, the
1998	  resultant kernel should continue to boot on existing non-EFI
1999	  platforms.
2000
2001config EFI_STUB
2002	bool "EFI stub support"
2003	depends on EFI
2004	select RELOCATABLE
2005	help
2006	  This kernel feature allows a bzImage to be loaded directly
2007	  by EFI firmware without the use of a bootloader.
2008
2009	  See Documentation/admin-guide/efi-stub.rst for more information.
2010
2011config EFI_HANDOVER_PROTOCOL
2012	bool "EFI handover protocol (DEPRECATED)"
2013	depends on EFI_STUB
2014	default y
2015	help
2016	  Select this in order to include support for the deprecated EFI
2017	  handover protocol, which defines alternative entry points into the
2018	  EFI stub.  This is a practice that has no basis in the UEFI
2019	  specification, and requires a priori knowledge on the part of the
2020	  bootloader about Linux/x86 specific ways of passing the command line
2021	  and initrd, and where in memory those assets may be loaded.
2022
2023	  If in doubt, say Y. Even though the corresponding support is not
2024	  present in upstream GRUB or other bootloaders, most distros build
2025	  GRUB with numerous downstream patches applied, and may rely on the
2026	  handover protocol as as result.
2027
2028config EFI_MIXED
2029	bool "EFI mixed-mode support"
2030	depends on EFI_STUB && X86_64
2031	help
2032	  Enabling this feature allows a 64-bit kernel to be booted
2033	  on a 32-bit firmware, provided that your CPU supports 64-bit
2034	  mode.
2035
2036	  Note that it is not possible to boot a mixed-mode enabled
2037	  kernel via the EFI boot stub - a bootloader that supports
2038	  the EFI handover protocol must be used.
2039
2040	  If unsure, say N.
2041
2042config EFI_FAKE_MEMMAP
2043	bool "Enable EFI fake memory map"
2044	depends on EFI
2045	help
2046	  Saying Y here will enable "efi_fake_mem" boot option.  By specifying
2047	  this parameter, you can add arbitrary attribute to specific memory
2048	  range by updating original (firmware provided) EFI memmap.  This is
2049	  useful for debugging of EFI memmap related feature, e.g., Address
2050	  Range Mirroring feature.
2051
2052config EFI_MAX_FAKE_MEM
2053	int "maximum allowable number of ranges in efi_fake_mem boot option"
2054	depends on EFI_FAKE_MEMMAP
2055	range 1 128
2056	default 8
2057	help
2058	  Maximum allowable number of ranges in efi_fake_mem boot option.
2059	  Ranges can be set up to this value using comma-separated list.
2060	  The default value is 8.
2061
2062config EFI_RUNTIME_MAP
2063	bool "Export EFI runtime maps to sysfs" if EXPERT
2064	depends on EFI
2065	help
2066	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2067	  That memory map is required by the 2nd kernel to set up EFI virtual
2068	  mappings after kexec, but can also be used for debugging purposes.
2069
2070	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2071
2072source "kernel/Kconfig.hz"
2073
2074config ARCH_SUPPORTS_KEXEC
2075	def_bool y
2076
2077config ARCH_SUPPORTS_KEXEC_FILE
2078	def_bool X86_64
2079
2080config ARCH_SELECTS_KEXEC_FILE
2081	def_bool y
2082	depends on KEXEC_FILE
2083	select HAVE_IMA_KEXEC if IMA
2084
2085config ARCH_SUPPORTS_KEXEC_PURGATORY
2086	def_bool y
2087
2088config ARCH_SUPPORTS_KEXEC_SIG
2089	def_bool y
2090
2091config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2092	def_bool y
2093
2094config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2095	def_bool y
2096
2097config ARCH_SUPPORTS_KEXEC_JUMP
2098	def_bool y
2099
2100config ARCH_SUPPORTS_CRASH_DUMP
2101	def_bool X86_64 || (X86_32 && HIGHMEM)
2102
2103config ARCH_SUPPORTS_CRASH_HOTPLUG
2104	def_bool y
2105
2106config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2107	def_bool CRASH_RESERVE
2108
2109config PHYSICAL_START
2110	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2111	default "0x1000000"
2112	help
2113	  This gives the physical address where the kernel is loaded.
2114
2115	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2116	  will decompress itself to above physical address and run from there.
2117	  Otherwise, bzImage will run from the address where it has been loaded
2118	  by the boot loader. The only exception is if it is loaded below the
2119	  above physical address, in which case it will relocate itself there.
2120
2121	  In normal kdump cases one does not have to set/change this option
2122	  as now bzImage can be compiled as a completely relocatable image
2123	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2124	  address. This option is mainly useful for the folks who don't want
2125	  to use a bzImage for capturing the crash dump and want to use a
2126	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2127	  to be specifically compiled to run from a specific memory area
2128	  (normally a reserved region) and this option comes handy.
2129
2130	  So if you are using bzImage for capturing the crash dump,
2131	  leave the value here unchanged to 0x1000000 and set
2132	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2133	  for capturing the crash dump change this value to start of
2134	  the reserved region.  In other words, it can be set based on
2135	  the "X" value as specified in the "crashkernel=YM@XM"
2136	  command line boot parameter passed to the panic-ed
2137	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2138	  for more details about crash dumps.
2139
2140	  Usage of bzImage for capturing the crash dump is recommended as
2141	  one does not have to build two kernels. Same kernel can be used
2142	  as production kernel and capture kernel. Above option should have
2143	  gone away after relocatable bzImage support is introduced. But it
2144	  is present because there are users out there who continue to use
2145	  vmlinux for dump capture. This option should go away down the
2146	  line.
2147
2148	  Don't change this unless you know what you are doing.
2149
2150config RELOCATABLE
2151	bool "Build a relocatable kernel"
2152	default y
2153	help
2154	  This builds a kernel image that retains relocation information
2155	  so it can be loaded someplace besides the default 1MB.
2156	  The relocations tend to make the kernel binary about 10% larger,
2157	  but are discarded at runtime.
2158
2159	  One use is for the kexec on panic case where the recovery kernel
2160	  must live at a different physical address than the primary
2161	  kernel.
2162
2163	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2164	  it has been loaded at and the compile time physical address
2165	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2166
2167config RANDOMIZE_BASE
2168	bool "Randomize the address of the kernel image (KASLR)"
2169	depends on RELOCATABLE
2170	default y
2171	help
2172	  In support of Kernel Address Space Layout Randomization (KASLR),
2173	  this randomizes the physical address at which the kernel image
2174	  is decompressed and the virtual address where the kernel
2175	  image is mapped, as a security feature that deters exploit
2176	  attempts relying on knowledge of the location of kernel
2177	  code internals.
2178
2179	  On 64-bit, the kernel physical and virtual addresses are
2180	  randomized separately. The physical address will be anywhere
2181	  between 16MB and the top of physical memory (up to 64TB). The
2182	  virtual address will be randomized from 16MB up to 1GB (9 bits
2183	  of entropy). Note that this also reduces the memory space
2184	  available to kernel modules from 1.5GB to 1GB.
2185
2186	  On 32-bit, the kernel physical and virtual addresses are
2187	  randomized together. They will be randomized from 16MB up to
2188	  512MB (8 bits of entropy).
2189
2190	  Entropy is generated using the RDRAND instruction if it is
2191	  supported. If RDTSC is supported, its value is mixed into
2192	  the entropy pool as well. If neither RDRAND nor RDTSC are
2193	  supported, then entropy is read from the i8254 timer. The
2194	  usable entropy is limited by the kernel being built using
2195	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2196	  minimum of 2MB. As a result, only 10 bits of entropy are
2197	  theoretically possible, but the implementations are further
2198	  limited due to memory layouts.
2199
2200	  If unsure, say Y.
2201
2202# Relocation on x86 needs some additional build support
2203config X86_NEED_RELOCS
2204	def_bool y
2205	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2206
2207config PHYSICAL_ALIGN
2208	hex "Alignment value to which kernel should be aligned"
2209	default "0x200000"
2210	range 0x2000 0x1000000 if X86_32
2211	range 0x200000 0x1000000 if X86_64
2212	help
2213	  This value puts the alignment restrictions on physical address
2214	  where kernel is loaded and run from. Kernel is compiled for an
2215	  address which meets above alignment restriction.
2216
2217	  If bootloader loads the kernel at a non-aligned address and
2218	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2219	  address aligned to above value and run from there.
2220
2221	  If bootloader loads the kernel at a non-aligned address and
2222	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2223	  load address and decompress itself to the address it has been
2224	  compiled for and run from there. The address for which kernel is
2225	  compiled already meets above alignment restrictions. Hence the
2226	  end result is that kernel runs from a physical address meeting
2227	  above alignment restrictions.
2228
2229	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2230	  this value must be a multiple of 0x200000.
2231
2232	  Don't change this unless you know what you are doing.
2233
2234config DYNAMIC_MEMORY_LAYOUT
2235	bool
2236	help
2237	  This option makes base addresses of vmalloc and vmemmap as well as
2238	  __PAGE_OFFSET movable during boot.
2239
2240config RANDOMIZE_MEMORY
2241	bool "Randomize the kernel memory sections"
2242	depends on X86_64
2243	depends on RANDOMIZE_BASE
2244	select DYNAMIC_MEMORY_LAYOUT
2245	default RANDOMIZE_BASE
2246	help
2247	  Randomizes the base virtual address of kernel memory sections
2248	  (physical memory mapping, vmalloc & vmemmap). This security feature
2249	  makes exploits relying on predictable memory locations less reliable.
2250
2251	  The order of allocations remains unchanged. Entropy is generated in
2252	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2253	  configuration have in average 30,000 different possible virtual
2254	  addresses for each memory section.
2255
2256	  If unsure, say Y.
2257
2258config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2259	hex "Physical memory mapping padding" if EXPERT
2260	depends on RANDOMIZE_MEMORY
2261	default "0xa" if MEMORY_HOTPLUG
2262	default "0x0"
2263	range 0x1 0x40 if MEMORY_HOTPLUG
2264	range 0x0 0x40
2265	help
2266	  Define the padding in terabytes added to the existing physical
2267	  memory size during kernel memory randomization. It is useful
2268	  for memory hotplug support but reduces the entropy available for
2269	  address randomization.
2270
2271	  If unsure, leave at the default value.
2272
2273config ADDRESS_MASKING
2274	bool "Linear Address Masking support"
2275	depends on X86_64
2276	help
2277	  Linear Address Masking (LAM) modifies the checking that is applied
2278	  to 64-bit linear addresses, allowing software to use of the
2279	  untranslated address bits for metadata.
2280
2281	  The capability can be used for efficient address sanitizers (ASAN)
2282	  implementation and for optimizations in JITs.
2283
2284config HOTPLUG_CPU
2285	def_bool y
2286	depends on SMP
2287
2288config COMPAT_VDSO
2289	def_bool n
2290	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2291	depends on COMPAT_32
2292	help
2293	  Certain buggy versions of glibc will crash if they are
2294	  presented with a 32-bit vDSO that is not mapped at the address
2295	  indicated in its segment table.
2296
2297	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2298	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2299	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2300	  the only released version with the bug, but OpenSUSE 9
2301	  contains a buggy "glibc 2.3.2".
2302
2303	  The symptom of the bug is that everything crashes on startup, saying:
2304	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2305
2306	  Saying Y here changes the default value of the vdso32 boot
2307	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2308	  This works around the glibc bug but hurts performance.
2309
2310	  If unsure, say N: if you are compiling your own kernel, you
2311	  are unlikely to be using a buggy version of glibc.
2312
2313choice
2314	prompt "vsyscall table for legacy applications"
2315	depends on X86_64
2316	default LEGACY_VSYSCALL_XONLY
2317	help
2318	  Legacy user code that does not know how to find the vDSO expects
2319	  to be able to issue three syscalls by calling fixed addresses in
2320	  kernel space. Since this location is not randomized with ASLR,
2321	  it can be used to assist security vulnerability exploitation.
2322
2323	  This setting can be changed at boot time via the kernel command
2324	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2325	  is deprecated and can only be enabled using the kernel command
2326	  line.
2327
2328	  On a system with recent enough glibc (2.14 or newer) and no
2329	  static binaries, you can say None without a performance penalty
2330	  to improve security.
2331
2332	  If unsure, select "Emulate execution only".
2333
2334	config LEGACY_VSYSCALL_XONLY
2335		bool "Emulate execution only"
2336		help
2337		  The kernel traps and emulates calls into the fixed vsyscall
2338		  address mapping and does not allow reads.  This
2339		  configuration is recommended when userspace might use the
2340		  legacy vsyscall area but support for legacy binary
2341		  instrumentation of legacy code is not needed.  It mitigates
2342		  certain uses of the vsyscall area as an ASLR-bypassing
2343		  buffer.
2344
2345	config LEGACY_VSYSCALL_NONE
2346		bool "None"
2347		help
2348		  There will be no vsyscall mapping at all. This will
2349		  eliminate any risk of ASLR bypass due to the vsyscall
2350		  fixed address mapping. Attempts to use the vsyscalls
2351		  will be reported to dmesg, so that either old or
2352		  malicious userspace programs can be identified.
2353
2354endchoice
2355
2356config CMDLINE_BOOL
2357	bool "Built-in kernel command line"
2358	help
2359	  Allow for specifying boot arguments to the kernel at
2360	  build time.  On some systems (e.g. embedded ones), it is
2361	  necessary or convenient to provide some or all of the
2362	  kernel boot arguments with the kernel itself (that is,
2363	  to not rely on the boot loader to provide them.)
2364
2365	  To compile command line arguments into the kernel,
2366	  set this option to 'Y', then fill in the
2367	  boot arguments in CONFIG_CMDLINE.
2368
2369	  Systems with fully functional boot loaders (i.e. non-embedded)
2370	  should leave this option set to 'N'.
2371
2372config CMDLINE
2373	string "Built-in kernel command string"
2374	depends on CMDLINE_BOOL
2375	default ""
2376	help
2377	  Enter arguments here that should be compiled into the kernel
2378	  image and used at boot time.  If the boot loader provides a
2379	  command line at boot time, it is appended to this string to
2380	  form the full kernel command line, when the system boots.
2381
2382	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2383	  change this behavior.
2384
2385	  In most cases, the command line (whether built-in or provided
2386	  by the boot loader) should specify the device for the root
2387	  file system.
2388
2389config CMDLINE_OVERRIDE
2390	bool "Built-in command line overrides boot loader arguments"
2391	depends on CMDLINE_BOOL && CMDLINE != ""
2392	help
2393	  Set this option to 'Y' to have the kernel ignore the boot loader
2394	  command line, and use ONLY the built-in command line.
2395
2396	  This is used to work around broken boot loaders.  This should
2397	  be set to 'N' under normal conditions.
2398
2399config MODIFY_LDT_SYSCALL
2400	bool "Enable the LDT (local descriptor table)" if EXPERT
2401	default y
2402	help
2403	  Linux can allow user programs to install a per-process x86
2404	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2405	  call.  This is required to run 16-bit or segmented code such as
2406	  DOSEMU or some Wine programs.  It is also used by some very old
2407	  threading libraries.
2408
2409	  Enabling this feature adds a small amount of overhead to
2410	  context switches and increases the low-level kernel attack
2411	  surface.  Disabling it removes the modify_ldt(2) system call.
2412
2413	  Saying 'N' here may make sense for embedded or server kernels.
2414
2415config STRICT_SIGALTSTACK_SIZE
2416	bool "Enforce strict size checking for sigaltstack"
2417	depends on DYNAMIC_SIGFRAME
2418	help
2419	  For historical reasons MINSIGSTKSZ is a constant which became
2420	  already too small with AVX512 support. Add a mechanism to
2421	  enforce strict checking of the sigaltstack size against the
2422	  real size of the FPU frame. This option enables the check
2423	  by default. It can also be controlled via the kernel command
2424	  line option 'strict_sas_size' independent of this config
2425	  switch. Enabling it might break existing applications which
2426	  allocate a too small sigaltstack but 'work' because they
2427	  never get a signal delivered.
2428
2429	  Say 'N' unless you want to really enforce this check.
2430
2431source "kernel/livepatch/Kconfig"
2432
2433endmenu
2434
2435config CC_HAS_NAMED_AS
2436	def_bool CC_IS_GCC && GCC_VERSION >= 120100
2437
2438config USE_X86_SEG_SUPPORT
2439	def_bool y
2440	depends on CC_HAS_NAMED_AS
2441	#
2442	# -fsanitize=kernel-address (KASAN) is at the moment incompatible
2443	# with named address spaces - see GCC PR sanitizer/111736.
2444	#
2445	depends on !KASAN
2446
2447config CC_HAS_SLS
2448	def_bool $(cc-option,-mharden-sls=all)
2449
2450config CC_HAS_RETURN_THUNK
2451	def_bool $(cc-option,-mfunction-return=thunk-extern)
2452
2453config CC_HAS_ENTRY_PADDING
2454	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2455
2456config FUNCTION_PADDING_CFI
2457	int
2458	default 59 if FUNCTION_ALIGNMENT_64B
2459	default 27 if FUNCTION_ALIGNMENT_32B
2460	default 11 if FUNCTION_ALIGNMENT_16B
2461	default  3 if FUNCTION_ALIGNMENT_8B
2462	default  0
2463
2464# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2465# except Kconfig can't do arithmetic :/
2466config FUNCTION_PADDING_BYTES
2467	int
2468	default FUNCTION_PADDING_CFI if CFI_CLANG
2469	default FUNCTION_ALIGNMENT
2470
2471config CALL_PADDING
2472	def_bool n
2473	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2474	select FUNCTION_ALIGNMENT_16B
2475
2476config FINEIBT
2477	def_bool y
2478	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
2479	select CALL_PADDING
2480
2481config HAVE_CALL_THUNKS
2482	def_bool y
2483	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2484
2485config CALL_THUNKS
2486	def_bool n
2487	select CALL_PADDING
2488
2489config PREFIX_SYMBOLS
2490	def_bool y
2491	depends on CALL_PADDING && !CFI_CLANG
2492
2493menuconfig SPECULATION_MITIGATIONS
2494	bool "Mitigations for speculative execution vulnerabilities"
2495	default y
2496	help
2497	  Say Y here to enable options which enable mitigations for
2498	  speculative execution hardware vulnerabilities.
2499
2500	  If you say N, all mitigations will be disabled. You really
2501	  should know what you are doing to say so.
2502
2503if SPECULATION_MITIGATIONS
2504
2505config MITIGATION_PAGE_TABLE_ISOLATION
2506	bool "Remove the kernel mapping in user mode"
2507	default y
2508	depends on (X86_64 || X86_PAE)
2509	help
2510	  This feature reduces the number of hardware side channels by
2511	  ensuring that the majority of kernel addresses are not mapped
2512	  into userspace.
2513
2514	  See Documentation/arch/x86/pti.rst for more details.
2515
2516config MITIGATION_RETPOLINE
2517	bool "Avoid speculative indirect branches in kernel"
2518	select OBJTOOL if HAVE_OBJTOOL
2519	default y
2520	help
2521	  Compile kernel with the retpoline compiler options to guard against
2522	  kernel-to-user data leaks by avoiding speculative indirect
2523	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2524	  support for full protection. The kernel may run slower.
2525
2526config MITIGATION_RETHUNK
2527	bool "Enable return-thunks"
2528	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2529	select OBJTOOL if HAVE_OBJTOOL
2530	default y if X86_64
2531	help
2532	  Compile the kernel with the return-thunks compiler option to guard
2533	  against kernel-to-user data leaks by avoiding return speculation.
2534	  Requires a compiler with -mfunction-return=thunk-extern
2535	  support for full protection. The kernel may run slower.
2536
2537config MITIGATION_UNRET_ENTRY
2538	bool "Enable UNRET on kernel entry"
2539	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2540	default y
2541	help
2542	  Compile the kernel with support for the retbleed=unret mitigation.
2543
2544config MITIGATION_CALL_DEPTH_TRACKING
2545	bool "Mitigate RSB underflow with call depth tracking"
2546	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2547	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2548	select CALL_THUNKS
2549	default y
2550	help
2551	  Compile the kernel with call depth tracking to mitigate the Intel
2552	  SKL Return-Speculation-Buffer (RSB) underflow issue. The
2553	  mitigation is off by default and needs to be enabled on the
2554	  kernel command line via the retbleed=stuff option. For
2555	  non-affected systems the overhead of this option is marginal as
2556	  the call depth tracking is using run-time generated call thunks
2557	  in a compiler generated padding area and call patching. This
2558	  increases text size by ~5%. For non affected systems this space
2559	  is unused. On affected SKL systems this results in a significant
2560	  performance gain over the IBRS mitigation.
2561
2562config CALL_THUNKS_DEBUG
2563	bool "Enable call thunks and call depth tracking debugging"
2564	depends on MITIGATION_CALL_DEPTH_TRACKING
2565	select FUNCTION_ALIGNMENT_32B
2566	default n
2567	help
2568	  Enable call/ret counters for imbalance detection and build in
2569	  a noisy dmesg about callthunks generation and call patching for
2570	  trouble shooting. The debug prints need to be enabled on the
2571	  kernel command line with 'debug-callthunks'.
2572	  Only enable this when you are debugging call thunks as this
2573	  creates a noticeable runtime overhead. If unsure say N.
2574
2575config MITIGATION_IBPB_ENTRY
2576	bool "Enable IBPB on kernel entry"
2577	depends on CPU_SUP_AMD && X86_64
2578	default y
2579	help
2580	  Compile the kernel with support for the retbleed=ibpb mitigation.
2581
2582config MITIGATION_IBRS_ENTRY
2583	bool "Enable IBRS on kernel entry"
2584	depends on CPU_SUP_INTEL && X86_64
2585	default y
2586	help
2587	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2588	  This mitigates both spectre_v2 and retbleed at great cost to
2589	  performance.
2590
2591config MITIGATION_SRSO
2592	bool "Mitigate speculative RAS overflow on AMD"
2593	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2594	default y
2595	help
2596	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2597
2598config MITIGATION_SLS
2599	bool "Mitigate Straight-Line-Speculation"
2600	depends on CC_HAS_SLS && X86_64
2601	select OBJTOOL if HAVE_OBJTOOL
2602	default n
2603	help
2604	  Compile the kernel with straight-line-speculation options to guard
2605	  against straight line speculation. The kernel image might be slightly
2606	  larger.
2607
2608config MITIGATION_GDS_FORCE
2609	bool "Force GDS Mitigation"
2610	depends on CPU_SUP_INTEL
2611	default n
2612	help
2613	  Gather Data Sampling (GDS) is a hardware vulnerability which allows
2614	  unprivileged speculative access to data which was previously stored in
2615	  vector registers.
2616
2617	  This option is equivalent to setting gather_data_sampling=force on the
2618	  command line. The microcode mitigation is used if present, otherwise
2619	  AVX is disabled as a mitigation. On affected systems that are missing
2620	  the microcode any userspace code that unconditionally uses AVX will
2621	  break with this option set.
2622
2623	  Setting this option on systems not vulnerable to GDS has no effect.
2624
2625	  If in doubt, say N.
2626
2627config MITIGATION_RFDS
2628	bool "RFDS Mitigation"
2629	depends on CPU_SUP_INTEL
2630	default y
2631	help
2632	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2633	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2634	  allows unprivileged speculative access to stale data previously
2635	  stored in floating point, vector and integer registers.
2636	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2637
2638endif
2639
2640config ARCH_HAS_ADD_PAGES
2641	def_bool y
2642	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2643
2644menu "Power management and ACPI options"
2645
2646config ARCH_HIBERNATION_HEADER
2647	def_bool y
2648	depends on HIBERNATION
2649
2650source "kernel/power/Kconfig"
2651
2652source "drivers/acpi/Kconfig"
2653
2654config X86_APM_BOOT
2655	def_bool y
2656	depends on APM
2657
2658menuconfig APM
2659	tristate "APM (Advanced Power Management) BIOS support"
2660	depends on X86_32 && PM_SLEEP
2661	help
2662	  APM is a BIOS specification for saving power using several different
2663	  techniques. This is mostly useful for battery powered laptops with
2664	  APM compliant BIOSes. If you say Y here, the system time will be
2665	  reset after a RESUME operation, the /proc/apm device will provide
2666	  battery status information, and user-space programs will receive
2667	  notification of APM "events" (e.g. battery status change).
2668
2669	  If you select "Y" here, you can disable actual use of the APM
2670	  BIOS by passing the "apm=off" option to the kernel at boot time.
2671
2672	  Note that the APM support is almost completely disabled for
2673	  machines with more than one CPU.
2674
2675	  In order to use APM, you will need supporting software. For location
2676	  and more information, read <file:Documentation/power/apm-acpi.rst>
2677	  and the Battery Powered Linux mini-HOWTO, available from
2678	  <http://www.tldp.org/docs.html#howto>.
2679
2680	  This driver does not spin down disk drives (see the hdparm(8)
2681	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2682	  VESA-compliant "green" monitors.
2683
2684	  This driver does not support the TI 4000M TravelMate and the ACER
2685	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2686	  desktop machines also don't have compliant BIOSes, and this driver
2687	  may cause those machines to panic during the boot phase.
2688
2689	  Generally, if you don't have a battery in your machine, there isn't
2690	  much point in using this driver and you should say N. If you get
2691	  random kernel OOPSes or reboots that don't seem to be related to
2692	  anything, try disabling/enabling this option (or disabling/enabling
2693	  APM in your BIOS).
2694
2695	  Some other things you should try when experiencing seemingly random,
2696	  "weird" problems:
2697
2698	  1) make sure that you have enough swap space and that it is
2699	  enabled.
2700	  2) pass the "idle=poll" option to the kernel
2701	  3) switch on floating point emulation in the kernel and pass
2702	  the "no387" option to the kernel
2703	  4) pass the "floppy=nodma" option to the kernel
2704	  5) pass the "mem=4M" option to the kernel (thereby disabling
2705	  all but the first 4 MB of RAM)
2706	  6) make sure that the CPU is not over clocked.
2707	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2708	  8) disable the cache from your BIOS settings
2709	  9) install a fan for the video card or exchange video RAM
2710	  10) install a better fan for the CPU
2711	  11) exchange RAM chips
2712	  12) exchange the motherboard.
2713
2714	  To compile this driver as a module, choose M here: the
2715	  module will be called apm.
2716
2717if APM
2718
2719config APM_IGNORE_USER_SUSPEND
2720	bool "Ignore USER SUSPEND"
2721	help
2722	  This option will ignore USER SUSPEND requests. On machines with a
2723	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2724	  series notebooks, it is necessary to say Y because of a BIOS bug.
2725
2726config APM_DO_ENABLE
2727	bool "Enable PM at boot time"
2728	help
2729	  Enable APM features at boot time. From page 36 of the APM BIOS
2730	  specification: "When disabled, the APM BIOS does not automatically
2731	  power manage devices, enter the Standby State, enter the Suspend
2732	  State, or take power saving steps in response to CPU Idle calls."
2733	  This driver will make CPU Idle calls when Linux is idle (unless this
2734	  feature is turned off -- see "Do CPU IDLE calls", below). This
2735	  should always save battery power, but more complicated APM features
2736	  will be dependent on your BIOS implementation. You may need to turn
2737	  this option off if your computer hangs at boot time when using APM
2738	  support, or if it beeps continuously instead of suspending. Turn
2739	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2740	  T400CDT. This is off by default since most machines do fine without
2741	  this feature.
2742
2743config APM_CPU_IDLE
2744	depends on CPU_IDLE
2745	bool "Make CPU Idle calls when idle"
2746	help
2747	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2748	  On some machines, this can activate improved power savings, such as
2749	  a slowed CPU clock rate, when the machine is idle. These idle calls
2750	  are made after the idle loop has run for some length of time (e.g.,
2751	  333 mS). On some machines, this will cause a hang at boot time or
2752	  whenever the CPU becomes idle. (On machines with more than one CPU,
2753	  this option does nothing.)
2754
2755config APM_DISPLAY_BLANK
2756	bool "Enable console blanking using APM"
2757	help
2758	  Enable console blanking using the APM. Some laptops can use this to
2759	  turn off the LCD backlight when the screen blanker of the Linux
2760	  virtual console blanks the screen. Note that this is only used by
2761	  the virtual console screen blanker, and won't turn off the backlight
2762	  when using the X Window system. This also doesn't have anything to
2763	  do with your VESA-compliant power-saving monitor. Further, this
2764	  option doesn't work for all laptops -- it might not turn off your
2765	  backlight at all, or it might print a lot of errors to the console,
2766	  especially if you are using gpm.
2767
2768config APM_ALLOW_INTS
2769	bool "Allow interrupts during APM BIOS calls"
2770	help
2771	  Normally we disable external interrupts while we are making calls to
2772	  the APM BIOS as a measure to lessen the effects of a badly behaving
2773	  BIOS implementation.  The BIOS should reenable interrupts if it
2774	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2775	  many of the newer IBM Thinkpads.  If you experience hangs when you
2776	  suspend, try setting this to Y.  Otherwise, say N.
2777
2778endif # APM
2779
2780source "drivers/cpufreq/Kconfig"
2781
2782source "drivers/cpuidle/Kconfig"
2783
2784source "drivers/idle/Kconfig"
2785
2786endmenu
2787
2788menu "Bus options (PCI etc.)"
2789
2790choice
2791	prompt "PCI access mode"
2792	depends on X86_32 && PCI
2793	default PCI_GOANY
2794	help
2795	  On PCI systems, the BIOS can be used to detect the PCI devices and
2796	  determine their configuration. However, some old PCI motherboards
2797	  have BIOS bugs and may crash if this is done. Also, some embedded
2798	  PCI-based systems don't have any BIOS at all. Linux can also try to
2799	  detect the PCI hardware directly without using the BIOS.
2800
2801	  With this option, you can specify how Linux should detect the
2802	  PCI devices. If you choose "BIOS", the BIOS will be used,
2803	  if you choose "Direct", the BIOS won't be used, and if you
2804	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2805	  If you choose "Any", the kernel will try MMCONFIG, then the
2806	  direct access method and falls back to the BIOS if that doesn't
2807	  work. If unsure, go with the default, which is "Any".
2808
2809config PCI_GOBIOS
2810	bool "BIOS"
2811
2812config PCI_GOMMCONFIG
2813	bool "MMConfig"
2814
2815config PCI_GODIRECT
2816	bool "Direct"
2817
2818config PCI_GOOLPC
2819	bool "OLPC XO-1"
2820	depends on OLPC
2821
2822config PCI_GOANY
2823	bool "Any"
2824
2825endchoice
2826
2827config PCI_BIOS
2828	def_bool y
2829	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2830
2831# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2832config PCI_DIRECT
2833	def_bool y
2834	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2835
2836config PCI_MMCONFIG
2837	bool "Support mmconfig PCI config space access" if X86_64
2838	default y
2839	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2840	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2841
2842config PCI_OLPC
2843	def_bool y
2844	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2845
2846config PCI_XEN
2847	def_bool y
2848	depends on PCI && XEN
2849
2850config MMCONF_FAM10H
2851	def_bool y
2852	depends on X86_64 && PCI_MMCONFIG && ACPI
2853
2854config PCI_CNB20LE_QUIRK
2855	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2856	depends on PCI
2857	help
2858	  Read the PCI windows out of the CNB20LE host bridge. This allows
2859	  PCI hotplug to work on systems with the CNB20LE chipset which do
2860	  not have ACPI.
2861
2862	  There's no public spec for this chipset, and this functionality
2863	  is known to be incomplete.
2864
2865	  You should say N unless you know you need this.
2866
2867config ISA_BUS
2868	bool "ISA bus support on modern systems" if EXPERT
2869	help
2870	  Expose ISA bus device drivers and options available for selection and
2871	  configuration. Enable this option if your target machine has an ISA
2872	  bus. ISA is an older system, displaced by PCI and newer bus
2873	  architectures -- if your target machine is modern, it probably does
2874	  not have an ISA bus.
2875
2876	  If unsure, say N.
2877
2878# x86_64 have no ISA slots, but can have ISA-style DMA.
2879config ISA_DMA_API
2880	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2881	default y
2882	help
2883	  Enables ISA-style DMA support for devices requiring such controllers.
2884	  If unsure, say Y.
2885
2886if X86_32
2887
2888config ISA
2889	bool "ISA support"
2890	help
2891	  Find out whether you have ISA slots on your motherboard.  ISA is the
2892	  name of a bus system, i.e. the way the CPU talks to the other stuff
2893	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2894	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2895	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2896
2897config SCx200
2898	tristate "NatSemi SCx200 support"
2899	help
2900	  This provides basic support for National Semiconductor's
2901	  (now AMD's) Geode processors.  The driver probes for the
2902	  PCI-IDs of several on-chip devices, so its a good dependency
2903	  for other scx200_* drivers.
2904
2905	  If compiled as a module, the driver is named scx200.
2906
2907config SCx200HR_TIMER
2908	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2909	depends on SCx200
2910	default y
2911	help
2912	  This driver provides a clocksource built upon the on-chip
2913	  27MHz high-resolution timer.  Its also a workaround for
2914	  NSC Geode SC-1100's buggy TSC, which loses time when the
2915	  processor goes idle (as is done by the scheduler).  The
2916	  other workaround is idle=poll boot option.
2917
2918config OLPC
2919	bool "One Laptop Per Child support"
2920	depends on !X86_PAE
2921	select GPIOLIB
2922	select OF
2923	select OF_PROMTREE
2924	select IRQ_DOMAIN
2925	select OLPC_EC
2926	help
2927	  Add support for detecting the unique features of the OLPC
2928	  XO hardware.
2929
2930config OLPC_XO1_PM
2931	bool "OLPC XO-1 Power Management"
2932	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2933	help
2934	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2935
2936config OLPC_XO1_RTC
2937	bool "OLPC XO-1 Real Time Clock"
2938	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2939	help
2940	  Add support for the XO-1 real time clock, which can be used as a
2941	  programmable wakeup source.
2942
2943config OLPC_XO1_SCI
2944	bool "OLPC XO-1 SCI extras"
2945	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2946	depends on INPUT=y
2947	select POWER_SUPPLY
2948	help
2949	  Add support for SCI-based features of the OLPC XO-1 laptop:
2950	   - EC-driven system wakeups
2951	   - Power button
2952	   - Ebook switch
2953	   - Lid switch
2954	   - AC adapter status updates
2955	   - Battery status updates
2956
2957config OLPC_XO15_SCI
2958	bool "OLPC XO-1.5 SCI extras"
2959	depends on OLPC && ACPI
2960	select POWER_SUPPLY
2961	help
2962	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2963	   - EC-driven system wakeups
2964	   - AC adapter status updates
2965	   - Battery status updates
2966
2967config ALIX
2968	bool "PCEngines ALIX System Support (LED setup)"
2969	select GPIOLIB
2970	help
2971	  This option enables system support for the PCEngines ALIX.
2972	  At present this just sets up LEDs for GPIO control on
2973	  ALIX2/3/6 boards.  However, other system specific setup should
2974	  get added here.
2975
2976	  Note: You must still enable the drivers for GPIO and LED support
2977	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2978
2979	  Note: You have to set alix.force=1 for boards with Award BIOS.
2980
2981config NET5501
2982	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2983	select GPIOLIB
2984	help
2985	  This option enables system support for the Soekris Engineering net5501.
2986
2987config GEOS
2988	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
2989	select GPIOLIB
2990	depends on DMI
2991	help
2992	  This option enables system support for the Traverse Technologies GEOS.
2993
2994config TS5500
2995	bool "Technologic Systems TS-5500 platform support"
2996	depends on MELAN
2997	select CHECK_SIGNATURE
2998	select NEW_LEDS
2999	select LEDS_CLASS
3000	help
3001	  This option enables system support for the Technologic Systems TS-5500.
3002
3003endif # X86_32
3004
3005config AMD_NB
3006	def_bool y
3007	depends on CPU_SUP_AMD && PCI
3008
3009endmenu
3010
3011menu "Binary Emulations"
3012
3013config IA32_EMULATION
3014	bool "IA32 Emulation"
3015	depends on X86_64
3016	select ARCH_WANT_OLD_COMPAT_IPC
3017	select BINFMT_ELF
3018	select COMPAT_OLD_SIGACTION
3019	help
3020	  Include code to run legacy 32-bit programs under a
3021	  64-bit kernel. You should likely turn this on, unless you're
3022	  100% sure that you don't have any 32-bit programs left.
3023
3024config IA32_EMULATION_DEFAULT_DISABLED
3025	bool "IA32 emulation disabled by default"
3026	default n
3027	depends on IA32_EMULATION
3028	help
3029	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3030	  processes and access to 32-bit syscalls. If unsure, leave it to its
3031	  default value.
3032
3033config X86_X32_ABI
3034	bool "x32 ABI for 64-bit mode"
3035	depends on X86_64
3036	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3037	# compressed debug sections to x86_x32 properly:
3038	# https://github.com/ClangBuiltLinux/linux/issues/514
3039	# https://github.com/ClangBuiltLinux/linux/issues/1141
3040	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3041	help
3042	  Include code to run binaries for the x32 native 32-bit ABI
3043	  for 64-bit processors.  An x32 process gets access to the
3044	  full 64-bit register file and wide data path while leaving
3045	  pointers at 32 bits for smaller memory footprint.
3046
3047config COMPAT_32
3048	def_bool y
3049	depends on IA32_EMULATION || X86_32
3050	select HAVE_UID16
3051	select OLD_SIGSUSPEND3
3052
3053config COMPAT
3054	def_bool y
3055	depends on IA32_EMULATION || X86_X32_ABI
3056
3057config COMPAT_FOR_U64_ALIGNMENT
3058	def_bool y
3059	depends on COMPAT
3060
3061endmenu
3062
3063config HAVE_ATOMIC_IOMAP
3064	def_bool y
3065	depends on X86_32
3066
3067source "arch/x86/kvm/Kconfig"
3068
3069source "arch/x86/Kconfig.assembler"
3070