xref: /linux/arch/x86/Kconfig (revision 1d0dc857b5d8711ff0f037bea9a0c13049c1763c)
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_CONFIGURES_CPU_MITIGATIONS
66	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
67	select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION
68	select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64
69	select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG
70	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE)
71	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
72	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
73	select ARCH_HAS_CACHE_LINE_SIZE
74	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION
75	select ARCH_HAS_CPU_FINALIZE_INIT
76	select ARCH_HAS_CPU_PASID		if IOMMU_SVA
77	select ARCH_HAS_CURRENT_STACK_POINTER
78	select ARCH_HAS_DEBUG_VIRTUAL
79	select ARCH_HAS_DEBUG_VM_PGTABLE	if !X86_PAE
80	select ARCH_HAS_DEVMEM_IS_ALLOWED
81	select ARCH_HAS_EARLY_DEBUG		if KGDB
82	select ARCH_HAS_ELF_RANDOMIZE
83	select ARCH_HAS_FAST_MULTIPLIER
84	select ARCH_HAS_FORTIFY_SOURCE
85	select ARCH_HAS_GCOV_PROFILE_ALL
86	select ARCH_HAS_KCOV			if X86_64
87	select ARCH_HAS_MEM_ENCRYPT
88	select ARCH_HAS_MEMBARRIER_SYNC_CORE
89	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
90	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
91	select ARCH_HAS_PMEM_API		if X86_64
92	select ARCH_HAS_PTE_DEVMAP		if X86_64
93	select ARCH_HAS_PTE_SPECIAL
94	select ARCH_HAS_HW_PTE_YOUNG
95	select ARCH_HAS_NONLEAF_PMD_YOUNG	if PGTABLE_LEVELS > 2
96	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64
97	select ARCH_HAS_COPY_MC			if X86_64
98	select ARCH_HAS_SET_MEMORY
99	select ARCH_HAS_SET_DIRECT_MAP
100	select ARCH_HAS_STRICT_KERNEL_RWX
101	select ARCH_HAS_STRICT_MODULE_RWX
102	select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
103	select ARCH_HAS_SYSCALL_WRAPPER
104	select ARCH_HAS_UBSAN
105	select ARCH_HAS_DEBUG_WX
106	select ARCH_HAS_ZONE_DMA_SET if EXPERT
107	select ARCH_HAVE_NMI_SAFE_CMPXCHG
108	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
109	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
110	select ARCH_MIGHT_HAVE_PC_PARPORT
111	select ARCH_MIGHT_HAVE_PC_SERIO
112	select ARCH_STACKWALK
113	select ARCH_SUPPORTS_ACPI
114	select ARCH_SUPPORTS_ATOMIC_RMW
115	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
116	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
117	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
118	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
119	select ARCH_SUPPORTS_CFI_CLANG		if X86_64
120	select ARCH_USES_CFI_TRAPS		if X86_64 && CFI_CLANG
121	select ARCH_SUPPORTS_LTO_CLANG
122	select ARCH_SUPPORTS_LTO_CLANG_THIN
123	select ARCH_USE_BUILTIN_BSWAP
124	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CMPXCHG64
125	select ARCH_USE_MEMTEST
126	select ARCH_USE_QUEUED_RWLOCKS
127	select ARCH_USE_QUEUED_SPINLOCKS
128	select ARCH_USE_SYM_ANNOTATIONS
129	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
130	select ARCH_WANT_DEFAULT_BPF_JIT	if X86_64
131	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
132	select ARCH_WANTS_NO_INSTR
133	select ARCH_WANT_GENERAL_HUGETLB
134	select ARCH_WANT_HUGE_PMD_SHARE
135	select ARCH_WANT_LD_ORPHAN_WARN
136	select ARCH_WANT_OPTIMIZE_DAX_VMEMMAP	if X86_64
137	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP	if X86_64
138	select ARCH_WANTS_THP_SWAP		if X86_64
139	select ARCH_HAS_PARANOID_L1D_FLUSH
140	select BUILDTIME_TABLE_SORT
141	select CLKEVT_I8253
142	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
143	select CLOCKSOURCE_WATCHDOG
144	# Word-size accesses may read uninitialized data past the trailing \0
145	# in strings and cause false KMSAN reports.
146	select DCACHE_WORD_ACCESS		if !KMSAN
147	select DYNAMIC_SIGFRAME
148	select EDAC_ATOMIC_SCRUB
149	select EDAC_SUPPORT
150	select GENERIC_CLOCKEVENTS_BROADCAST	if X86_64 || (X86_32 && X86_LOCAL_APIC)
151	select GENERIC_CLOCKEVENTS_BROADCAST_IDLE	if GENERIC_CLOCKEVENTS_BROADCAST
152	select GENERIC_CLOCKEVENTS_MIN_ADJUST
153	select GENERIC_CMOS_UPDATE
154	select GENERIC_CPU_AUTOPROBE
155	select GENERIC_CPU_DEVICES
156	select GENERIC_CPU_VULNERABILITIES
157	select GENERIC_EARLY_IOREMAP
158	select GENERIC_ENTRY
159	select GENERIC_IOMAP
160	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP
161	select GENERIC_IRQ_MATRIX_ALLOCATOR	if X86_LOCAL_APIC
162	select GENERIC_IRQ_MIGRATION		if SMP
163	select GENERIC_IRQ_PROBE
164	select GENERIC_IRQ_RESERVATION_MODE
165	select GENERIC_IRQ_SHOW
166	select GENERIC_PENDING_IRQ		if SMP
167	select GENERIC_PTDUMP
168	select GENERIC_SMP_IDLE_THREAD
169	select GENERIC_TIME_VSYSCALL
170	select GENERIC_GETTIMEOFDAY
171	select GENERIC_VDSO_TIME_NS
172	select GUP_GET_PXX_LOW_HIGH		if X86_PAE
173	select HARDIRQS_SW_RESEND
174	select HARDLOCKUP_CHECK_TIMESTAMP	if X86_64
175	select HAS_IOPORT
176	select HAVE_ACPI_APEI			if ACPI
177	select HAVE_ACPI_APEI_NMI		if ACPI
178	select HAVE_ALIGNED_STRUCT_PAGE
179	select HAVE_ARCH_AUDITSYSCALL
180	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
181	select HAVE_ARCH_HUGE_VMALLOC		if X86_64
182	select HAVE_ARCH_JUMP_LABEL
183	select HAVE_ARCH_JUMP_LABEL_RELATIVE
184	select HAVE_ARCH_KASAN			if X86_64
185	select HAVE_ARCH_KASAN_VMALLOC		if X86_64
186	select HAVE_ARCH_KFENCE
187	select HAVE_ARCH_KMSAN			if X86_64
188	select HAVE_ARCH_KGDB
189	select HAVE_ARCH_MMAP_RND_BITS		if MMU
190	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
191	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
192	select HAVE_ARCH_PREL32_RELOCATIONS
193	select HAVE_ARCH_SECCOMP_FILTER
194	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
195	select HAVE_ARCH_STACKLEAK
196	select HAVE_ARCH_TRACEHOOK
197	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
198	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
199	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
200	select HAVE_ARCH_USERFAULTFD_MINOR	if X86_64 && USERFAULTFD
201	select HAVE_ARCH_VMAP_STACK		if X86_64
202	select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
203	select HAVE_ARCH_WITHIN_STACK_FRAMES
204	select HAVE_ASM_MODVERSIONS
205	select HAVE_CMPXCHG_DOUBLE
206	select HAVE_CMPXCHG_LOCAL
207	select HAVE_CONTEXT_TRACKING_USER		if X86_64
208	select HAVE_CONTEXT_TRACKING_USER_OFFSTACK	if HAVE_CONTEXT_TRACKING_USER
209	select HAVE_C_RECORDMCOUNT
210	select HAVE_OBJTOOL_MCOUNT		if HAVE_OBJTOOL
211	select HAVE_OBJTOOL_NOP_MCOUNT		if HAVE_OBJTOOL_MCOUNT
212	select HAVE_BUILDTIME_MCOUNT_SORT
213	select HAVE_DEBUG_KMEMLEAK
214	select HAVE_DMA_CONTIGUOUS
215	select HAVE_DYNAMIC_FTRACE
216	select HAVE_DYNAMIC_FTRACE_WITH_REGS
217	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
218	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
219	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
220	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if X86_64
221	select HAVE_EBPF_JIT
222	select HAVE_EFFICIENT_UNALIGNED_ACCESS
223	select HAVE_EISA
224	select HAVE_EXIT_THREAD
225	select HAVE_FAST_GUP
226	select HAVE_FENTRY			if X86_64 || DYNAMIC_FTRACE
227	select HAVE_FTRACE_MCOUNT_RECORD
228	select HAVE_FUNCTION_GRAPH_RETVAL	if HAVE_FUNCTION_GRAPH_TRACER
229	select HAVE_FUNCTION_GRAPH_TRACER	if X86_32 || (X86_64 && DYNAMIC_FTRACE)
230	select HAVE_FUNCTION_TRACER
231	select HAVE_GCC_PLUGINS
232	select HAVE_HW_BREAKPOINT
233	select HAVE_IOREMAP_PROT
234	select HAVE_IRQ_EXIT_ON_IRQ_STACK	if X86_64
235	select HAVE_IRQ_TIME_ACCOUNTING
236	select HAVE_JUMP_LABEL_HACK		if HAVE_OBJTOOL
237	select HAVE_KERNEL_BZIP2
238	select HAVE_KERNEL_GZIP
239	select HAVE_KERNEL_LZ4
240	select HAVE_KERNEL_LZMA
241	select HAVE_KERNEL_LZO
242	select HAVE_KERNEL_XZ
243	select HAVE_KERNEL_ZSTD
244	select HAVE_KPROBES
245	select HAVE_KPROBES_ON_FTRACE
246	select HAVE_FUNCTION_ERROR_INJECTION
247	select HAVE_KRETPROBES
248	select HAVE_RETHOOK
249	select HAVE_LIVEPATCH			if X86_64
250	select HAVE_MIXED_BREAKPOINTS_REGS
251	select HAVE_MOD_ARCH_SPECIFIC
252	select HAVE_MOVE_PMD
253	select HAVE_MOVE_PUD
254	select HAVE_NOINSTR_HACK		if HAVE_OBJTOOL
255	select HAVE_NMI
256	select HAVE_NOINSTR_VALIDATION		if HAVE_OBJTOOL
257	select HAVE_OBJTOOL			if X86_64
258	select HAVE_OPTPROBES
259	select HAVE_PAGE_SIZE_4KB
260	select HAVE_PCSPKR_PLATFORM
261	select HAVE_PERF_EVENTS
262	select HAVE_PERF_EVENTS_NMI
263	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
264	select HAVE_PCI
265	select HAVE_PERF_REGS
266	select HAVE_PERF_USER_STACK_DUMP
267	select MMU_GATHER_RCU_TABLE_FREE	if PARAVIRT
268	select MMU_GATHER_MERGE_VMAS
269	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
270	select HAVE_REGS_AND_STACK_ACCESS_API
271	select HAVE_RELIABLE_STACKTRACE		if UNWINDER_ORC || STACK_VALIDATION
272	select HAVE_FUNCTION_ARG_ACCESS_API
273	select HAVE_SETUP_PER_CPU_AREA
274	select HAVE_SOFTIRQ_ON_OWN_STACK
275	select HAVE_STACKPROTECTOR		if CC_HAS_SANE_STACKPROTECTOR
276	select HAVE_STACK_VALIDATION		if HAVE_OBJTOOL
277	select HAVE_STATIC_CALL
278	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
279	select HAVE_PREEMPT_DYNAMIC_CALL
280	select HAVE_RSEQ
281	select HAVE_RUST			if X86_64
282	select HAVE_SYSCALL_TRACEPOINTS
283	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
284	select HAVE_UNSTABLE_SCHED_CLOCK
285	select HAVE_USER_RETURN_NOTIFIER
286	select HAVE_GENERIC_VDSO
287	select HOTPLUG_PARALLEL			if SMP && X86_64
288	select HOTPLUG_SMT			if SMP
289	select HOTPLUG_SPLIT_STARTUP		if SMP && X86_32
290	select IRQ_FORCED_THREADING
291	select LOCK_MM_AND_FIND_VMA
292	select NEED_PER_CPU_EMBED_FIRST_CHUNK
293	select NEED_PER_CPU_PAGE_FIRST_CHUNK
294	select NEED_SG_DMA_LENGTH
295	select PCI_DOMAINS			if PCI
296	select PCI_LOCKLESS_CONFIG		if PCI
297	select PERF_EVENTS
298	select RTC_LIB
299	select RTC_MC146818_LIB
300	select SPARSE_IRQ
301	select SYSCTL_EXCEPTION_TRACE
302	select THREAD_INFO_IN_TASK
303	select TRACE_IRQFLAGS_SUPPORT
304	select TRACE_IRQFLAGS_NMI_SUPPORT
305	select USER_STACKTRACE_SUPPORT
306	select HAVE_ARCH_KCSAN			if X86_64
307	select PROC_PID_ARCH_STATUS		if PROC_FS
308	select HAVE_ARCH_NODE_DEV_GROUP		if X86_SGX
309	select FUNCTION_ALIGNMENT_16B		if X86_64 || X86_ALIGNMENT_16
310	select FUNCTION_ALIGNMENT_4B
311	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
312	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
313
314config INSTRUCTION_DECODER
315	def_bool y
316	depends on KPROBES || PERF_EVENTS || UPROBES
317
318config OUTPUT_FORMAT
319	string
320	default "elf32-i386" if X86_32
321	default "elf64-x86-64" if X86_64
322
323config LOCKDEP_SUPPORT
324	def_bool y
325
326config STACKTRACE_SUPPORT
327	def_bool y
328
329config MMU
330	def_bool y
331
332config ARCH_MMAP_RND_BITS_MIN
333	default 28 if 64BIT
334	default 8
335
336config ARCH_MMAP_RND_BITS_MAX
337	default 32 if 64BIT
338	default 16
339
340config ARCH_MMAP_RND_COMPAT_BITS_MIN
341	default 8
342
343config ARCH_MMAP_RND_COMPAT_BITS_MAX
344	default 16
345
346config SBUS
347	bool
348
349config GENERIC_ISA_DMA
350	def_bool y
351	depends on ISA_DMA_API
352
353config GENERIC_CSUM
354	bool
355	default y if KMSAN || KASAN
356
357config GENERIC_BUG
358	def_bool y
359	depends on BUG
360	select GENERIC_BUG_RELATIVE_POINTERS if X86_64
361
362config GENERIC_BUG_RELATIVE_POINTERS
363	bool
364
365config ARCH_MAY_HAVE_PC_FDC
366	def_bool y
367	depends on ISA_DMA_API
368
369config GENERIC_CALIBRATE_DELAY
370	def_bool y
371
372config ARCH_HAS_CPU_RELAX
373	def_bool y
374
375config ARCH_HIBERNATION_POSSIBLE
376	def_bool y
377
378config ARCH_SUSPEND_POSSIBLE
379	def_bool y
380
381config AUDIT_ARCH
382	def_bool y if X86_64
383
384config KASAN_SHADOW_OFFSET
385	hex
386	depends on KASAN
387	default 0xdffffc0000000000
388
389config HAVE_INTEL_TXT
390	def_bool y
391	depends on INTEL_IOMMU && ACPI
392
393config X86_64_SMP
394	def_bool y
395	depends on X86_64 && SMP
396
397config ARCH_SUPPORTS_UPROBES
398	def_bool y
399
400config FIX_EARLYCON_MEM
401	def_bool y
402
403config DYNAMIC_PHYSICAL_MASK
404	bool
405
406config PGTABLE_LEVELS
407	int
408	default 5 if X86_5LEVEL
409	default 4 if X86_64
410	default 3 if X86_PAE
411	default 2
412
413config CC_HAS_SANE_STACKPROTECTOR
414	bool
415	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC) $(CLANG_FLAGS)) if 64BIT
416	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC) $(CLANG_FLAGS))
417	help
418	  We have to make sure stack protector is unconditionally disabled if
419	  the compiler produces broken code or if it does not let us control
420	  the segment on 32-bit kernels.
421
422menu "Processor type and features"
423
424config SMP
425	bool "Symmetric multi-processing support"
426	help
427	  This enables support for systems with more than one CPU. If you have
428	  a system with only one CPU, say N. If you have a system with more
429	  than one CPU, say Y.
430
431	  If you say N here, the kernel will run on uni- and multiprocessor
432	  machines, but will use only one CPU of a multiprocessor machine. If
433	  you say Y here, the kernel will run on many, but not all,
434	  uniprocessor machines. On a uniprocessor machine, the kernel
435	  will run faster if you say N here.
436
437	  Note that if you say Y here and choose architecture "586" or
438	  "Pentium" under "Processor family", the kernel will not work on 486
439	  architectures. Similarly, multiprocessor kernels for the "PPro"
440	  architecture may not work on all Pentium based boards.
441
442	  People using multiprocessor machines who say Y here should also say
443	  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
444	  Management" code will be disabled if you say Y here.
445
446	  See also <file:Documentation/arch/x86/i386/IO-APIC.rst>,
447	  <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO available at
448	  <http://www.tldp.org/docs.html#howto>.
449
450	  If you don't know what to do here, say N.
451
452config X86_X2APIC
453	bool "Support x2apic"
454	depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
455	help
456	  This enables x2apic support on CPUs that have this feature.
457
458	  This allows 32-bit apic IDs (so it can support very large systems),
459	  and accesses the local apic via MSRs not via mmio.
460
461	  Some Intel systems circa 2022 and later are locked into x2APIC mode
462	  and can not fall back to the legacy APIC modes if SGX or TDX are
463	  enabled in the BIOS. They will boot with very reduced functionality
464	  without enabling this option.
465
466	  If you don't know what to do here, say N.
467
468config X86_MPPARSE
469	bool "Enable MPS table" if ACPI
470	default y
471	depends on X86_LOCAL_APIC
472	help
473	  For old smp systems that do not have proper acpi support. Newer systems
474	  (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
475
476config X86_CPU_RESCTRL
477	bool "x86 CPU resource control support"
478	depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
479	select KERNFS
480	select PROC_CPU_RESCTRL		if PROC_FS
481	help
482	  Enable x86 CPU resource control support.
483
484	  Provide support for the allocation and monitoring of system resources
485	  usage by the CPU.
486
487	  Intel calls this Intel Resource Director Technology
488	  (Intel(R) RDT). More information about RDT can be found in the
489	  Intel x86 Architecture Software Developer Manual.
490
491	  AMD calls this AMD Platform Quality of Service (AMD QoS).
492	  More information about AMD QoS can be found in the AMD64 Technology
493	  Platform Quality of Service Extensions manual.
494
495	  Say N if unsure.
496
497config X86_FRED
498	bool "Flexible Return and Event Delivery"
499	depends on X86_64
500	help
501	  When enabled, try to use Flexible Return and Event Delivery
502	  instead of the legacy SYSCALL/SYSENTER/IDT architecture for
503	  ring transitions and exception/interrupt handling if the
504	  system supports.
505
506if X86_32
507config X86_BIGSMP
508	bool "Support for big SMP systems with more than 8 CPUs"
509	depends on SMP
510	help
511	  This option is needed for the systems that have more than 8 CPUs.
512
513config X86_EXTENDED_PLATFORM
514	bool "Support for extended (non-PC) x86 platforms"
515	default y
516	help
517	  If you disable this option then the kernel will only support
518	  standard PC platforms. (which covers the vast majority of
519	  systems out there.)
520
521	  If you enable this option then you'll be able to select support
522	  for the following (non-PC) 32 bit x86 platforms:
523		Goldfish (Android emulator)
524		AMD Elan
525		RDC R-321x SoC
526		SGI 320/540 (Visual Workstation)
527		STA2X11-based (e.g. Northville)
528		Moorestown MID devices
529
530	  If you have one of these systems, or if you want to build a
531	  generic distribution kernel, say Y here - otherwise say N.
532endif # X86_32
533
534if X86_64
535config X86_EXTENDED_PLATFORM
536	bool "Support for extended (non-PC) x86 platforms"
537	default y
538	help
539	  If you disable this option then the kernel will only support
540	  standard PC platforms. (which covers the vast majority of
541	  systems out there.)
542
543	  If you enable this option then you'll be able to select support
544	  for the following (non-PC) 64 bit x86 platforms:
545		Numascale NumaChip
546		ScaleMP vSMP
547		SGI Ultraviolet
548
549	  If you have one of these systems, or if you want to build a
550	  generic distribution kernel, say Y here - otherwise say N.
551endif # X86_64
552# This is an alphabetically sorted list of 64 bit extended platforms
553# Please maintain the alphabetic order if and when there are additions
554config X86_NUMACHIP
555	bool "Numascale NumaChip"
556	depends on X86_64
557	depends on X86_EXTENDED_PLATFORM
558	depends on NUMA
559	depends on SMP
560	depends on X86_X2APIC
561	depends on PCI_MMCONFIG
562	help
563	  Adds support for Numascale NumaChip large-SMP systems. Needed to
564	  enable more than ~168 cores.
565	  If you don't have one of these, you should say N here.
566
567config X86_VSMP
568	bool "ScaleMP vSMP"
569	select HYPERVISOR_GUEST
570	select PARAVIRT
571	depends on X86_64 && PCI
572	depends on X86_EXTENDED_PLATFORM
573	depends on SMP
574	help
575	  Support for ScaleMP vSMP systems.  Say 'Y' here if this kernel is
576	  supposed to run on these EM64T-based machines.  Only choose this option
577	  if you have one of these machines.
578
579config X86_UV
580	bool "SGI Ultraviolet"
581	depends on X86_64
582	depends on X86_EXTENDED_PLATFORM
583	depends on NUMA
584	depends on EFI
585	depends on KEXEC_CORE
586	depends on X86_X2APIC
587	depends on PCI
588	help
589	  This option is needed in order to support SGI Ultraviolet systems.
590	  If you don't have one of these, you should say N here.
591
592# Following is an alphabetically sorted list of 32 bit extended platforms
593# Please maintain the alphabetic order if and when there are additions
594
595config X86_GOLDFISH
596	bool "Goldfish (Virtual Platform)"
597	depends on X86_EXTENDED_PLATFORM
598	help
599	  Enable support for the Goldfish virtual platform used primarily
600	  for Android development. Unless you are building for the Android
601	  Goldfish emulator say N here.
602
603config X86_INTEL_CE
604	bool "CE4100 TV platform"
605	depends on PCI
606	depends on PCI_GODIRECT
607	depends on X86_IO_APIC
608	depends on X86_32
609	depends on X86_EXTENDED_PLATFORM
610	select X86_REBOOTFIXUPS
611	select OF
612	select OF_EARLY_FLATTREE
613	help
614	  Select for the Intel CE media processor (CE4100) SOC.
615	  This option compiles in support for the CE4100 SOC for settop
616	  boxes and media devices.
617
618config X86_INTEL_MID
619	bool "Intel MID platform support"
620	depends on X86_EXTENDED_PLATFORM
621	depends on X86_PLATFORM_DEVICES
622	depends on PCI
623	depends on X86_64 || (PCI_GOANY && X86_32)
624	depends on X86_IO_APIC
625	select I2C
626	select DW_APB_TIMER
627	select INTEL_SCU_PCI
628	help
629	  Select to build a kernel capable of supporting Intel MID (Mobile
630	  Internet Device) platform systems which do not have the PCI legacy
631	  interfaces. If you are building for a PC class system say N here.
632
633	  Intel MID platforms are based on an Intel processor and chipset which
634	  consume less power than most of the x86 derivatives.
635
636config X86_INTEL_QUARK
637	bool "Intel Quark platform support"
638	depends on X86_32
639	depends on X86_EXTENDED_PLATFORM
640	depends on X86_PLATFORM_DEVICES
641	depends on X86_TSC
642	depends on PCI
643	depends on PCI_GOANY
644	depends on X86_IO_APIC
645	select IOSF_MBI
646	select INTEL_IMR
647	select COMMON_CLK
648	help
649	  Select to include support for Quark X1000 SoC.
650	  Say Y here if you have a Quark based system such as the Arduino
651	  compatible Intel Galileo.
652
653config X86_INTEL_LPSS
654	bool "Intel Low Power Subsystem Support"
655	depends on X86 && ACPI && PCI
656	select COMMON_CLK
657	select PINCTRL
658	select IOSF_MBI
659	help
660	  Select to build support for Intel Low Power Subsystem such as
661	  found on Intel Lynxpoint PCH. Selecting this option enables
662	  things like clock tree (common clock framework) and pincontrol
663	  which are needed by the LPSS peripheral drivers.
664
665config X86_AMD_PLATFORM_DEVICE
666	bool "AMD ACPI2Platform devices support"
667	depends on ACPI
668	select COMMON_CLK
669	select PINCTRL
670	help
671	  Select to interpret AMD specific ACPI device to platform device
672	  such as I2C, UART, GPIO found on AMD Carrizo and later chipsets.
673	  I2C and UART depend on COMMON_CLK to set clock. GPIO driver is
674	  implemented under PINCTRL subsystem.
675
676config IOSF_MBI
677	tristate "Intel SoC IOSF Sideband support for SoC platforms"
678	depends on PCI
679	help
680	  This option enables sideband register access support for Intel SoC
681	  platforms. On these platforms the IOSF sideband is used in lieu of
682	  MSR's for some register accesses, mostly but not limited to thermal
683	  and power. Drivers may query the availability of this device to
684	  determine if they need the sideband in order to work on these
685	  platforms. The sideband is available on the following SoC products.
686	  This list is not meant to be exclusive.
687	   - BayTrail
688	   - Braswell
689	   - Quark
690
691	  You should say Y if you are running a kernel on one of these SoC's.
692
693config IOSF_MBI_DEBUG
694	bool "Enable IOSF sideband access through debugfs"
695	depends on IOSF_MBI && DEBUG_FS
696	help
697	  Select this option to expose the IOSF sideband access registers (MCR,
698	  MDR, MCRX) through debugfs to write and read register information from
699	  different units on the SoC. This is most useful for obtaining device
700	  state information for debug and analysis. As this is a general access
701	  mechanism, users of this option would have specific knowledge of the
702	  device they want to access.
703
704	  If you don't require the option or are in doubt, say N.
705
706config X86_RDC321X
707	bool "RDC R-321x SoC"
708	depends on X86_32
709	depends on X86_EXTENDED_PLATFORM
710	select M486
711	select X86_REBOOTFIXUPS
712	help
713	  This option is needed for RDC R-321x system-on-chip, also known
714	  as R-8610-(G).
715	  If you don't have one of these chips, you should say N here.
716
717config X86_32_NON_STANDARD
718	bool "Support non-standard 32-bit SMP architectures"
719	depends on X86_32 && SMP
720	depends on X86_EXTENDED_PLATFORM
721	help
722	  This option compiles in the bigsmp and STA2X11 default
723	  subarchitectures.  It is intended for a generic binary
724	  kernel. If you select them all, kernel will probe it one by
725	  one and will fallback to default.
726
727# Alphabetically sorted list of Non standard 32 bit platforms
728
729config X86_SUPPORTS_MEMORY_FAILURE
730	def_bool y
731	# MCE code calls memory_failure():
732	depends on X86_MCE
733	# On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
734	# On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
735	depends on X86_64 || !SPARSEMEM
736	select ARCH_SUPPORTS_MEMORY_FAILURE
737
738config STA2X11
739	bool "STA2X11 Companion Chip Support"
740	depends on X86_32_NON_STANDARD && PCI
741	select SWIOTLB
742	select MFD_STA2X11
743	select GPIOLIB
744	help
745	  This adds support for boards based on the STA2X11 IO-Hub,
746	  a.k.a. "ConneXt". The chip is used in place of the standard
747	  PC chipset, so all "standard" peripherals are missing. If this
748	  option is selected the kernel will still be able to boot on
749	  standard PC machines.
750
751config X86_32_IRIS
752	tristate "Eurobraille/Iris poweroff module"
753	depends on X86_32
754	help
755	  The Iris machines from EuroBraille do not have APM or ACPI support
756	  to shut themselves down properly.  A special I/O sequence is
757	  needed to do so, which is what this module does at
758	  kernel shutdown.
759
760	  This is only for Iris machines from EuroBraille.
761
762	  If unused, say N.
763
764config SCHED_OMIT_FRAME_POINTER
765	def_bool y
766	prompt "Single-depth WCHAN output"
767	depends on X86
768	help
769	  Calculate simpler /proc/<PID>/wchan values. If this option
770	  is disabled then wchan values will recurse back to the
771	  caller function. This provides more accurate wchan values,
772	  at the expense of slightly more scheduling overhead.
773
774	  If in doubt, say "Y".
775
776menuconfig HYPERVISOR_GUEST
777	bool "Linux guest support"
778	help
779	  Say Y here to enable options for running Linux under various hyper-
780	  visors. This option enables basic hypervisor detection and platform
781	  setup.
782
783	  If you say N, all options in this submenu will be skipped and
784	  disabled, and Linux guest support won't be built in.
785
786if HYPERVISOR_GUEST
787
788config PARAVIRT
789	bool "Enable paravirtualization code"
790	depends on HAVE_STATIC_CALL
791	help
792	  This changes the kernel so it can modify itself when it is run
793	  under a hypervisor, potentially improving performance significantly
794	  over full virtualization.  However, when run without a hypervisor
795	  the kernel is theoretically slower and slightly larger.
796
797config PARAVIRT_XXL
798	bool
799
800config PARAVIRT_DEBUG
801	bool "paravirt-ops debugging"
802	depends on PARAVIRT && DEBUG_KERNEL
803	help
804	  Enable to debug paravirt_ops internals.  Specifically, BUG if
805	  a paravirt_op is missing when it is called.
806
807config PARAVIRT_SPINLOCKS
808	bool "Paravirtualization layer for spinlocks"
809	depends on PARAVIRT && SMP
810	help
811	  Paravirtualized spinlocks allow a pvops backend to replace the
812	  spinlock implementation with something virtualization-friendly
813	  (for example, block the virtual CPU rather than spinning).
814
815	  It has a minimal impact on native kernels and gives a nice performance
816	  benefit on paravirtualized KVM / Xen kernels.
817
818	  If you are unsure how to answer this question, answer Y.
819
820config X86_HV_CALLBACK_VECTOR
821	def_bool n
822
823source "arch/x86/xen/Kconfig"
824
825config KVM_GUEST
826	bool "KVM Guest support (including kvmclock)"
827	depends on PARAVIRT
828	select PARAVIRT_CLOCK
829	select ARCH_CPUIDLE_HALTPOLL
830	select X86_HV_CALLBACK_VECTOR
831	default y
832	help
833	  This option enables various optimizations for running under the KVM
834	  hypervisor. It includes a paravirtualized clock, so that instead
835	  of relying on a PIT (or probably other) emulation by the
836	  underlying device model, the host provides the guest with
837	  timing infrastructure such as time of day, and system time
838
839config ARCH_CPUIDLE_HALTPOLL
840	def_bool n
841	prompt "Disable host haltpoll when loading haltpoll driver"
842	help
843	  If virtualized under KVM, disable host haltpoll.
844
845config PVH
846	bool "Support for running PVH guests"
847	help
848	  This option enables the PVH entry point for guest virtual machines
849	  as specified in the x86/HVM direct boot ABI.
850
851config PARAVIRT_TIME_ACCOUNTING
852	bool "Paravirtual steal time accounting"
853	depends on PARAVIRT
854	help
855	  Select this option to enable fine granularity task steal time
856	  accounting. Time spent executing other tasks in parallel with
857	  the current vCPU is discounted from the vCPU power. To account for
858	  that, there can be a small performance impact.
859
860	  If in doubt, say N here.
861
862config PARAVIRT_CLOCK
863	bool
864
865config JAILHOUSE_GUEST
866	bool "Jailhouse non-root cell support"
867	depends on X86_64 && PCI
868	select X86_PM_TIMER
869	help
870	  This option allows to run Linux as guest in a Jailhouse non-root
871	  cell. You can leave this option disabled if you only want to start
872	  Jailhouse and run Linux afterwards in the root cell.
873
874config ACRN_GUEST
875	bool "ACRN Guest support"
876	depends on X86_64
877	select X86_HV_CALLBACK_VECTOR
878	help
879	  This option allows to run Linux as guest in the ACRN hypervisor. ACRN is
880	  a flexible, lightweight reference open-source hypervisor, built with
881	  real-time and safety-criticality in mind. It is built for embedded
882	  IOT with small footprint and real-time features. More details can be
883	  found in https://projectacrn.org/.
884
885config INTEL_TDX_GUEST
886	bool "Intel TDX (Trust Domain Extensions) - Guest Support"
887	depends on X86_64 && CPU_SUP_INTEL
888	depends on X86_X2APIC
889	depends on EFI_STUB
890	select ARCH_HAS_CC_PLATFORM
891	select X86_MEM_ENCRYPT
892	select X86_MCE
893	select UNACCEPTED_MEMORY
894	help
895	  Support running as a guest under Intel TDX.  Without this support,
896	  the guest kernel can not boot or run under TDX.
897	  TDX includes memory encryption and integrity capabilities
898	  which protect the confidentiality and integrity of guest
899	  memory contents and CPU state. TDX guests are protected from
900	  some attacks from the VMM.
901
902endif # HYPERVISOR_GUEST
903
904source "arch/x86/Kconfig.cpu"
905
906config HPET_TIMER
907	def_bool X86_64
908	prompt "HPET Timer Support" if X86_32
909	help
910	  Use the IA-PC HPET (High Precision Event Timer) to manage
911	  time in preference to the PIT and RTC, if a HPET is
912	  present.
913	  HPET is the next generation timer replacing legacy 8254s.
914	  The HPET provides a stable time base on SMP
915	  systems, unlike the TSC, but it is more expensive to access,
916	  as it is off-chip.  The interface used is documented
917	  in the HPET spec, revision 1.
918
919	  You can safely choose Y here.  However, HPET will only be
920	  activated if the platform and the BIOS support this feature.
921	  Otherwise the 8254 will be used for timing services.
922
923	  Choose N to continue using the legacy 8254 timer.
924
925config HPET_EMULATE_RTC
926	def_bool y
927	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
928
929# Mark as expert because too many people got it wrong.
930# The code disables itself when not needed.
931config DMI
932	default y
933	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
934	bool "Enable DMI scanning" if EXPERT
935	help
936	  Enabled scanning of DMI to identify machine quirks. Say Y
937	  here unless you have verified that your setup is not
938	  affected by entries in the DMI blacklist. Required by PNP
939	  BIOS code.
940
941config GART_IOMMU
942	bool "Old AMD GART IOMMU support"
943	select DMA_OPS
944	select IOMMU_HELPER
945	select SWIOTLB
946	depends on X86_64 && PCI && AMD_NB
947	help
948	  Provides a driver for older AMD Athlon64/Opteron/Turion/Sempron
949	  GART based hardware IOMMUs.
950
951	  The GART supports full DMA access for devices with 32-bit access
952	  limitations, on systems with more than 3 GB. This is usually needed
953	  for USB, sound, many IDE/SATA chipsets and some other devices.
954
955	  Newer systems typically have a modern AMD IOMMU, supported via
956	  the CONFIG_AMD_IOMMU=y config option.
957
958	  In normal configurations this driver is only active when needed:
959	  there's more than 3 GB of memory and the system contains a
960	  32-bit limited device.
961
962	  If unsure, say Y.
963
964config BOOT_VESA_SUPPORT
965	bool
966	help
967	  If true, at least one selected framebuffer driver can take advantage
968	  of VESA video modes set at an early boot stage via the vga= parameter.
969
970config MAXSMP
971	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
972	depends on X86_64 && SMP && DEBUG_KERNEL
973	select CPUMASK_OFFSTACK
974	help
975	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
976	  If unsure, say N.
977
978#
979# The maximum number of CPUs supported:
980#
981# The main config value is NR_CPUS, which defaults to NR_CPUS_DEFAULT,
982# and which can be configured interactively in the
983# [NR_CPUS_RANGE_BEGIN ... NR_CPUS_RANGE_END] range.
984#
985# The ranges are different on 32-bit and 64-bit kernels, depending on
986# hardware capabilities and scalability features of the kernel.
987#
988# ( If MAXSMP is enabled we just use the highest possible value and disable
989#   interactive configuration. )
990#
991
992config NR_CPUS_RANGE_BEGIN
993	int
994	default NR_CPUS_RANGE_END if MAXSMP
995	default    1 if !SMP
996	default    2
997
998config NR_CPUS_RANGE_END
999	int
1000	depends on X86_32
1001	default   64 if  SMP &&  X86_BIGSMP
1002	default    8 if  SMP && !X86_BIGSMP
1003	default    1 if !SMP
1004
1005config NR_CPUS_RANGE_END
1006	int
1007	depends on X86_64
1008	default 8192 if  SMP && CPUMASK_OFFSTACK
1009	default  512 if  SMP && !CPUMASK_OFFSTACK
1010	default    1 if !SMP
1011
1012config NR_CPUS_DEFAULT
1013	int
1014	depends on X86_32
1015	default   32 if  X86_BIGSMP
1016	default    8 if  SMP
1017	default    1 if !SMP
1018
1019config NR_CPUS_DEFAULT
1020	int
1021	depends on X86_64
1022	default 8192 if  MAXSMP
1023	default   64 if  SMP
1024	default    1 if !SMP
1025
1026config NR_CPUS
1027	int "Maximum number of CPUs" if SMP && !MAXSMP
1028	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
1029	default NR_CPUS_DEFAULT
1030	help
1031	  This allows you to specify the maximum number of CPUs which this
1032	  kernel will support.  If CPUMASK_OFFSTACK is enabled, the maximum
1033	  supported value is 8192, otherwise the maximum value is 512.  The
1034	  minimum value which makes sense is 2.
1035
1036	  This is purely to save memory: each supported CPU adds about 8KB
1037	  to the kernel image.
1038
1039config SCHED_CLUSTER
1040	bool "Cluster scheduler support"
1041	depends on SMP
1042	default y
1043	help
1044	  Cluster scheduler support improves the CPU scheduler's decision
1045	  making when dealing with machines that have clusters of CPUs.
1046	  Cluster usually means a couple of CPUs which are placed closely
1047	  by sharing mid-level caches, last-level cache tags or internal
1048	  busses.
1049
1050config SCHED_SMT
1051	def_bool y if SMP
1052
1053config SCHED_MC
1054	def_bool y
1055	prompt "Multi-core scheduler support"
1056	depends on SMP
1057	help
1058	  Multi-core scheduler support improves the CPU scheduler's decision
1059	  making when dealing with multi-core CPU chips at a cost of slightly
1060	  increased overhead in some places. If unsure say N here.
1061
1062config SCHED_MC_PRIO
1063	bool "CPU core priorities scheduler support"
1064	depends on SCHED_MC
1065	select X86_INTEL_PSTATE if CPU_SUP_INTEL
1066	select X86_AMD_PSTATE if CPU_SUP_AMD && ACPI
1067	select CPU_FREQ
1068	default y
1069	help
1070	  Intel Turbo Boost Max Technology 3.0 enabled CPUs have a
1071	  core ordering determined at manufacturing time, which allows
1072	  certain cores to reach higher turbo frequencies (when running
1073	  single threaded workloads) than others.
1074
1075	  Enabling this kernel feature teaches the scheduler about
1076	  the TBM3 (aka ITMT) priority order of the CPU cores and adjusts the
1077	  scheduler's CPU selection logic accordingly, so that higher
1078	  overall system performance can be achieved.
1079
1080	  This feature will have no effect on CPUs without this feature.
1081
1082	  If unsure say Y here.
1083
1084config UP_LATE_INIT
1085	def_bool y
1086	depends on !SMP && X86_LOCAL_APIC
1087
1088config X86_UP_APIC
1089	bool "Local APIC support on uniprocessors" if !PCI_MSI
1090	default PCI_MSI
1091	depends on X86_32 && !SMP && !X86_32_NON_STANDARD
1092	help
1093	  A local APIC (Advanced Programmable Interrupt Controller) is an
1094	  integrated interrupt controller in the CPU. If you have a single-CPU
1095	  system which has a processor with a local APIC, you can say Y here to
1096	  enable and use it. If you say Y here even though your machine doesn't
1097	  have a local APIC, then the kernel will still run with no slowdown at
1098	  all. The local APIC supports CPU-generated self-interrupts (timer,
1099	  performance counters), and the NMI watchdog which detects hard
1100	  lockups.
1101
1102config X86_UP_IOAPIC
1103	bool "IO-APIC support on uniprocessors"
1104	depends on X86_UP_APIC
1105	help
1106	  An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
1107	  SMP-capable replacement for PC-style interrupt controllers. Most
1108	  SMP systems and many recent uniprocessor systems have one.
1109
1110	  If you have a single-CPU system with an IO-APIC, you can say Y here
1111	  to use it. If you say Y here even though your machine doesn't have
1112	  an IO-APIC, then the kernel will still run with no slowdown at all.
1113
1114config X86_LOCAL_APIC
1115	def_bool y
1116	depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
1117	select IRQ_DOMAIN_HIERARCHY
1118
1119config X86_IO_APIC
1120	def_bool y
1121	depends on X86_LOCAL_APIC || X86_UP_IOAPIC
1122
1123config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
1124	bool "Reroute for broken boot IRQs"
1125	depends on X86_IO_APIC
1126	help
1127	  This option enables a workaround that fixes a source of
1128	  spurious interrupts. This is recommended when threaded
1129	  interrupt handling is used on systems where the generation of
1130	  superfluous "boot interrupts" cannot be disabled.
1131
1132	  Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
1133	  entry in the chipset's IO-APIC is masked (as, e.g. the RT
1134	  kernel does during interrupt handling). On chipsets where this
1135	  boot IRQ generation cannot be disabled, this workaround keeps
1136	  the original IRQ line masked so that only the equivalent "boot
1137	  IRQ" is delivered to the CPUs. The workaround also tells the
1138	  kernel to set up the IRQ handler on the boot IRQ line. In this
1139	  way only one interrupt is delivered to the kernel. Otherwise
1140	  the spurious second interrupt may cause the kernel to bring
1141	  down (vital) interrupt lines.
1142
1143	  Only affects "broken" chipsets. Interrupt sharing may be
1144	  increased on these systems.
1145
1146config X86_MCE
1147	bool "Machine Check / overheating reporting"
1148	select GENERIC_ALLOCATOR
1149	default y
1150	help
1151	  Machine Check support allows the processor to notify the
1152	  kernel if it detects a problem (e.g. overheating, data corruption).
1153	  The action the kernel takes depends on the severity of the problem,
1154	  ranging from warning messages to halting the machine.
1155
1156config X86_MCELOG_LEGACY
1157	bool "Support for deprecated /dev/mcelog character device"
1158	depends on X86_MCE
1159	help
1160	  Enable support for /dev/mcelog which is needed by the old mcelog
1161	  userspace logging daemon. Consider switching to the new generation
1162	  rasdaemon solution.
1163
1164config X86_MCE_INTEL
1165	def_bool y
1166	prompt "Intel MCE features"
1167	depends on X86_MCE && X86_LOCAL_APIC
1168	help
1169	  Additional support for intel specific MCE features such as
1170	  the thermal monitor.
1171
1172config X86_MCE_AMD
1173	def_bool y
1174	prompt "AMD MCE features"
1175	depends on X86_MCE && X86_LOCAL_APIC && AMD_NB
1176	help
1177	  Additional support for AMD specific MCE features such as
1178	  the DRAM Error Threshold.
1179
1180config X86_ANCIENT_MCE
1181	bool "Support for old Pentium 5 / WinChip machine checks"
1182	depends on X86_32 && X86_MCE
1183	help
1184	  Include support for machine check handling on old Pentium 5 or WinChip
1185	  systems. These typically need to be enabled explicitly on the command
1186	  line.
1187
1188config X86_MCE_THRESHOLD
1189	depends on X86_MCE_AMD || X86_MCE_INTEL
1190	def_bool y
1191
1192config X86_MCE_INJECT
1193	depends on X86_MCE && X86_LOCAL_APIC && DEBUG_FS
1194	tristate "Machine check injector support"
1195	help
1196	  Provide support for injecting machine checks for testing purposes.
1197	  If you don't know what a machine check is and you don't do kernel
1198	  QA it is safe to say n.
1199
1200source "arch/x86/events/Kconfig"
1201
1202config X86_LEGACY_VM86
1203	bool "Legacy VM86 support"
1204	depends on X86_32
1205	help
1206	  This option allows user programs to put the CPU into V8086
1207	  mode, which is an 80286-era approximation of 16-bit real mode.
1208
1209	  Some very old versions of X and/or vbetool require this option
1210	  for user mode setting.  Similarly, DOSEMU will use it if
1211	  available to accelerate real mode DOS programs.  However, any
1212	  recent version of DOSEMU, X, or vbetool should be fully
1213	  functional even without kernel VM86 support, as they will all
1214	  fall back to software emulation. Nevertheless, if you are using
1215	  a 16-bit DOS program where 16-bit performance matters, vm86
1216	  mode might be faster than emulation and you might want to
1217	  enable this option.
1218
1219	  Note that any app that works on a 64-bit kernel is unlikely to
1220	  need this option, as 64-bit kernels don't, and can't, support
1221	  V8086 mode. This option is also unrelated to 16-bit protected
1222	  mode and is not needed to run most 16-bit programs under Wine.
1223
1224	  Enabling this option increases the complexity of the kernel
1225	  and slows down exception handling a tiny bit.
1226
1227	  If unsure, say N here.
1228
1229config VM86
1230	bool
1231	default X86_LEGACY_VM86
1232
1233config X86_16BIT
1234	bool "Enable support for 16-bit segments" if EXPERT
1235	default y
1236	depends on MODIFY_LDT_SYSCALL
1237	help
1238	  This option is required by programs like Wine to run 16-bit
1239	  protected mode legacy code on x86 processors.  Disabling
1240	  this option saves about 300 bytes on i386, or around 6K text
1241	  plus 16K runtime memory on x86-64,
1242
1243config X86_ESPFIX32
1244	def_bool y
1245	depends on X86_16BIT && X86_32
1246
1247config X86_ESPFIX64
1248	def_bool y
1249	depends on X86_16BIT && X86_64
1250
1251config X86_VSYSCALL_EMULATION
1252	bool "Enable vsyscall emulation" if EXPERT
1253	default y
1254	depends on X86_64
1255	help
1256	  This enables emulation of the legacy vsyscall page.  Disabling
1257	  it is roughly equivalent to booting with vsyscall=none, except
1258	  that it will also disable the helpful warning if a program
1259	  tries to use a vsyscall.  With this option set to N, offending
1260	  programs will just segfault, citing addresses of the form
1261	  0xffffffffff600?00.
1262
1263	  This option is required by many programs built before 2013, and
1264	  care should be used even with newer programs if set to N.
1265
1266	  Disabling this option saves about 7K of kernel size and
1267	  possibly 4K of additional runtime pagetable memory.
1268
1269config X86_IOPL_IOPERM
1270	bool "IOPERM and IOPL Emulation"
1271	default y
1272	help
1273	  This enables the ioperm() and iopl() syscalls which are necessary
1274	  for legacy applications.
1275
1276	  Legacy IOPL support is an overbroad mechanism which allows user
1277	  space aside of accessing all 65536 I/O ports also to disable
1278	  interrupts. To gain this access the caller needs CAP_SYS_RAWIO
1279	  capabilities and permission from potentially active security
1280	  modules.
1281
1282	  The emulation restricts the functionality of the syscall to
1283	  only allowing the full range I/O port access, but prevents the
1284	  ability to disable interrupts from user space which would be
1285	  granted if the hardware IOPL mechanism would be used.
1286
1287config TOSHIBA
1288	tristate "Toshiba Laptop support"
1289	depends on X86_32
1290	help
1291	  This adds a driver to safely access the System Management Mode of
1292	  the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
1293	  not work on models with a Phoenix BIOS. The System Management Mode
1294	  is used to set the BIOS and power saving options on Toshiba portables.
1295
1296	  For information on utilities to make use of this driver see the
1297	  Toshiba Linux utilities web site at:
1298	  <http://www.buzzard.org.uk/toshiba/>.
1299
1300	  Say Y if you intend to run this kernel on a Toshiba portable.
1301	  Say N otherwise.
1302
1303config X86_REBOOTFIXUPS
1304	bool "Enable X86 board specific fixups for reboot"
1305	depends on X86_32
1306	help
1307	  This enables chipset and/or board specific fixups to be done
1308	  in order to get reboot to work correctly. This is only needed on
1309	  some combinations of hardware and BIOS. The symptom, for which
1310	  this config is intended, is when reboot ends with a stalled/hung
1311	  system.
1312
1313	  Currently, the only fixup is for the Geode machines using
1314	  CS5530A and CS5536 chipsets and the RDC R-321x SoC.
1315
1316	  Say Y if you want to enable the fixup. Currently, it's safe to
1317	  enable this option even if you don't need it.
1318	  Say N otherwise.
1319
1320config MICROCODE
1321	def_bool y
1322	depends on CPU_SUP_AMD || CPU_SUP_INTEL
1323
1324config MICROCODE_INITRD32
1325	def_bool y
1326	depends on MICROCODE && X86_32 && BLK_DEV_INITRD
1327
1328config MICROCODE_LATE_LOADING
1329	bool "Late microcode loading (DANGEROUS)"
1330	default n
1331	depends on MICROCODE && SMP
1332	help
1333	  Loading microcode late, when the system is up and executing instructions
1334	  is a tricky business and should be avoided if possible. Just the sequence
1335	  of synchronizing all cores and SMT threads is one fragile dance which does
1336	  not guarantee that cores might not softlock after the loading. Therefore,
1337	  use this at your own risk. Late loading taints the kernel unless the
1338	  microcode header indicates that it is safe for late loading via the
1339	  minimal revision check. This minimal revision check can be enforced on
1340	  the kernel command line with "microcode.minrev=Y".
1341
1342config MICROCODE_LATE_FORCE_MINREV
1343	bool "Enforce late microcode loading minimal revision check"
1344	default n
1345	depends on MICROCODE_LATE_LOADING
1346	help
1347	  To prevent that users load microcode late which modifies already
1348	  in use features, newer microcode patches have a minimum revision field
1349	  in the microcode header, which tells the kernel which minimum
1350	  revision must be active in the CPU to safely load that new microcode
1351	  late into the running system. If disabled the check will not
1352	  be enforced but the kernel will be tainted when the minimal
1353	  revision check fails.
1354
1355	  This minimal revision check can also be controlled via the
1356	  "microcode.minrev" parameter on the kernel command line.
1357
1358	  If unsure say Y.
1359
1360config X86_MSR
1361	tristate "/dev/cpu/*/msr - Model-specific register support"
1362	help
1363	  This device gives privileged processes access to the x86
1364	  Model-Specific Registers (MSRs).  It is a character device with
1365	  major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
1366	  MSR accesses are directed to a specific CPU on multi-processor
1367	  systems.
1368
1369config X86_CPUID
1370	tristate "/dev/cpu/*/cpuid - CPU information support"
1371	help
1372	  This device gives processes access to the x86 CPUID instruction to
1373	  be executed on a specific processor.  It is a character device
1374	  with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1375	  /dev/cpu/31/cpuid.
1376
1377choice
1378	prompt "High Memory Support"
1379	default HIGHMEM4G
1380	depends on X86_32
1381
1382config NOHIGHMEM
1383	bool "off"
1384	help
1385	  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1386	  However, the address space of 32-bit x86 processors is only 4
1387	  Gigabytes large. That means that, if you have a large amount of
1388	  physical memory, not all of it can be "permanently mapped" by the
1389	  kernel. The physical memory that's not permanently mapped is called
1390	  "high memory".
1391
1392	  If you are compiling a kernel which will never run on a machine with
1393	  more than 1 Gigabyte total physical RAM, answer "off" here (default
1394	  choice and suitable for most users). This will result in a "3GB/1GB"
1395	  split: 3GB are mapped so that each process sees a 3GB virtual memory
1396	  space and the remaining part of the 4GB virtual memory space is used
1397	  by the kernel to permanently map as much physical memory as
1398	  possible.
1399
1400	  If the machine has between 1 and 4 Gigabytes physical RAM, then
1401	  answer "4GB" here.
1402
1403	  If more than 4 Gigabytes is used then answer "64GB" here. This
1404	  selection turns Intel PAE (Physical Address Extension) mode on.
1405	  PAE implements 3-level paging on IA32 processors. PAE is fully
1406	  supported by Linux, PAE mode is implemented on all recent Intel
1407	  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1408	  then the kernel will not boot on CPUs that don't support PAE!
1409
1410	  The actual amount of total physical memory will either be
1411	  auto detected or can be forced by using a kernel command line option
1412	  such as "mem=256M". (Try "man bootparam" or see the documentation of
1413	  your boot loader (lilo or loadlin) about how to pass options to the
1414	  kernel at boot time.)
1415
1416	  If unsure, say "off".
1417
1418config HIGHMEM4G
1419	bool "4GB"
1420	help
1421	  Select this if you have a 32-bit processor and between 1 and 4
1422	  gigabytes of physical RAM.
1423
1424config HIGHMEM64G
1425	bool "64GB"
1426	depends on X86_HAVE_PAE
1427	select X86_PAE
1428	help
1429	  Select this if you have a 32-bit processor and more than 4
1430	  gigabytes of physical RAM.
1431
1432endchoice
1433
1434choice
1435	prompt "Memory split" if EXPERT
1436	default VMSPLIT_3G
1437	depends on X86_32
1438	help
1439	  Select the desired split between kernel and user memory.
1440
1441	  If the address range available to the kernel is less than the
1442	  physical memory installed, the remaining memory will be available
1443	  as "high memory". Accessing high memory is a little more costly
1444	  than low memory, as it needs to be mapped into the kernel first.
1445	  Note that increasing the kernel address space limits the range
1446	  available to user programs, making the address space there
1447	  tighter.  Selecting anything other than the default 3G/1G split
1448	  will also likely make your kernel incompatible with binary-only
1449	  kernel modules.
1450
1451	  If you are not absolutely sure what you are doing, leave this
1452	  option alone!
1453
1454	config VMSPLIT_3G
1455		bool "3G/1G user/kernel split"
1456	config VMSPLIT_3G_OPT
1457		depends on !X86_PAE
1458		bool "3G/1G user/kernel split (for full 1G low memory)"
1459	config VMSPLIT_2G
1460		bool "2G/2G user/kernel split"
1461	config VMSPLIT_2G_OPT
1462		depends on !X86_PAE
1463		bool "2G/2G user/kernel split (for full 2G low memory)"
1464	config VMSPLIT_1G
1465		bool "1G/3G user/kernel split"
1466endchoice
1467
1468config PAGE_OFFSET
1469	hex
1470	default 0xB0000000 if VMSPLIT_3G_OPT
1471	default 0x80000000 if VMSPLIT_2G
1472	default 0x78000000 if VMSPLIT_2G_OPT
1473	default 0x40000000 if VMSPLIT_1G
1474	default 0xC0000000
1475	depends on X86_32
1476
1477config HIGHMEM
1478	def_bool y
1479	depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1480
1481config X86_PAE
1482	bool "PAE (Physical Address Extension) Support"
1483	depends on X86_32 && X86_HAVE_PAE
1484	select PHYS_ADDR_T_64BIT
1485	select SWIOTLB
1486	help
1487	  PAE is required for NX support, and furthermore enables
1488	  larger swapspace support for non-overcommit purposes. It
1489	  has the cost of more pagetable lookup overhead, and also
1490	  consumes more pagetable space per process.
1491
1492config X86_5LEVEL
1493	bool "Enable 5-level page tables support"
1494	default y
1495	select DYNAMIC_MEMORY_LAYOUT
1496	select SPARSEMEM_VMEMMAP
1497	depends on X86_64
1498	help
1499	  5-level paging enables access to larger address space:
1500	  up to 128 PiB of virtual address space and 4 PiB of
1501	  physical address space.
1502
1503	  It will be supported by future Intel CPUs.
1504
1505	  A kernel with the option enabled can be booted on machines that
1506	  support 4- or 5-level paging.
1507
1508	  See Documentation/arch/x86/x86_64/5level-paging.rst for more
1509	  information.
1510
1511	  Say N if unsure.
1512
1513config X86_DIRECT_GBPAGES
1514	def_bool y
1515	depends on X86_64
1516	help
1517	  Certain kernel features effectively disable kernel
1518	  linear 1 GB mappings (even if the CPU otherwise
1519	  supports them), so don't confuse the user by printing
1520	  that we have them enabled.
1521
1522config X86_CPA_STATISTICS
1523	bool "Enable statistic for Change Page Attribute"
1524	depends on DEBUG_FS
1525	help
1526	  Expose statistics about the Change Page Attribute mechanism, which
1527	  helps to determine the effectiveness of preserving large and huge
1528	  page mappings when mapping protections are changed.
1529
1530config X86_MEM_ENCRYPT
1531	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
1532	select DYNAMIC_PHYSICAL_MASK
1533	def_bool n
1534
1535config AMD_MEM_ENCRYPT
1536	bool "AMD Secure Memory Encryption (SME) support"
1537	depends on X86_64 && CPU_SUP_AMD
1538	depends on EFI_STUB
1539	select DMA_COHERENT_POOL
1540	select ARCH_USE_MEMREMAP_PROT
1541	select INSTRUCTION_DECODER
1542	select ARCH_HAS_CC_PLATFORM
1543	select X86_MEM_ENCRYPT
1544	select UNACCEPTED_MEMORY
1545	help
1546	  Say yes to enable support for the encryption of system memory.
1547	  This requires an AMD processor that supports Secure Memory
1548	  Encryption (SME).
1549
1550# Common NUMA Features
1551config NUMA
1552	bool "NUMA Memory Allocation and Scheduler Support"
1553	depends on SMP
1554	depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP)
1555	default y if X86_BIGSMP
1556	select USE_PERCPU_NUMA_NODE_ID
1557	select OF_NUMA if OF
1558	help
1559	  Enable NUMA (Non-Uniform Memory Access) support.
1560
1561	  The kernel will try to allocate memory used by a CPU on the
1562	  local memory controller of the CPU and add some more
1563	  NUMA awareness to the kernel.
1564
1565	  For 64-bit this is recommended if the system is Intel Core i7
1566	  (or later), AMD Opteron, or EM64T NUMA.
1567
1568	  For 32-bit this is only needed if you boot a 32-bit
1569	  kernel on a 64-bit NUMA platform.
1570
1571	  Otherwise, you should say N.
1572
1573config AMD_NUMA
1574	def_bool y
1575	prompt "Old style AMD Opteron NUMA detection"
1576	depends on X86_64 && NUMA && PCI
1577	help
1578	  Enable AMD NUMA node topology detection.  You should say Y here if
1579	  you have a multi processor AMD system. This uses an old method to
1580	  read the NUMA configuration directly from the builtin Northbridge
1581	  of Opteron. It is recommended to use X86_64_ACPI_NUMA instead,
1582	  which also takes priority if both are compiled in.
1583
1584config X86_64_ACPI_NUMA
1585	def_bool y
1586	prompt "ACPI NUMA detection"
1587	depends on X86_64 && NUMA && ACPI && PCI
1588	select ACPI_NUMA
1589	help
1590	  Enable ACPI SRAT based node topology detection.
1591
1592config NUMA_EMU
1593	bool "NUMA emulation"
1594	depends on NUMA
1595	help
1596	  Enable NUMA emulation. A flat machine will be split
1597	  into virtual nodes when booted with "numa=fake=N", where N is the
1598	  number of nodes. This is only useful for debugging.
1599
1600config NODES_SHIFT
1601	int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1602	range 1 10
1603	default "10" if MAXSMP
1604	default "6" if X86_64
1605	default "3"
1606	depends on NUMA
1607	help
1608	  Specify the maximum number of NUMA Nodes available on the target
1609	  system.  Increases memory reserved to accommodate various tables.
1610
1611config ARCH_FLATMEM_ENABLE
1612	def_bool y
1613	depends on X86_32 && !NUMA
1614
1615config ARCH_SPARSEMEM_ENABLE
1616	def_bool y
1617	depends on X86_64 || NUMA || X86_32 || X86_32_NON_STANDARD
1618	select SPARSEMEM_STATIC if X86_32
1619	select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1620
1621config ARCH_SPARSEMEM_DEFAULT
1622	def_bool X86_64 || (NUMA && X86_32)
1623
1624config ARCH_SELECT_MEMORY_MODEL
1625	def_bool y
1626	depends on ARCH_SPARSEMEM_ENABLE && ARCH_FLATMEM_ENABLE
1627
1628config ARCH_MEMORY_PROBE
1629	bool "Enable sysfs memory/probe interface"
1630	depends on MEMORY_HOTPLUG
1631	help
1632	  This option enables a sysfs memory/probe interface for testing.
1633	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
1634	  If you are unsure how to answer this question, answer N.
1635
1636config ARCH_PROC_KCORE_TEXT
1637	def_bool y
1638	depends on X86_64 && PROC_KCORE
1639
1640config ILLEGAL_POINTER_VALUE
1641	hex
1642	default 0 if X86_32
1643	default 0xdead000000000000 if X86_64
1644
1645config X86_PMEM_LEGACY_DEVICE
1646	bool
1647
1648config X86_PMEM_LEGACY
1649	tristate "Support non-standard NVDIMMs and ADR protected memory"
1650	depends on PHYS_ADDR_T_64BIT
1651	depends on BLK_DEV
1652	select X86_PMEM_LEGACY_DEVICE
1653	select NUMA_KEEP_MEMINFO if NUMA
1654	select LIBNVDIMM
1655	help
1656	  Treat memory marked using the non-standard e820 type of 12 as used
1657	  by the Intel Sandy Bridge-EP reference BIOS as protected memory.
1658	  The kernel will offer these regions to the 'pmem' driver so
1659	  they can be used for persistent storage.
1660
1661	  Say Y if unsure.
1662
1663config HIGHPTE
1664	bool "Allocate 3rd-level pagetables from highmem"
1665	depends on HIGHMEM
1666	help
1667	  The VM uses one page table entry for each page of physical memory.
1668	  For systems with a lot of RAM, this can be wasteful of precious
1669	  low memory.  Setting this option will put user-space page table
1670	  entries in high memory.
1671
1672config X86_CHECK_BIOS_CORRUPTION
1673	bool "Check for low memory corruption"
1674	help
1675	  Periodically check for memory corruption in low memory, which
1676	  is suspected to be caused by BIOS.  Even when enabled in the
1677	  configuration, it is disabled at runtime.  Enable it by
1678	  setting "memory_corruption_check=1" on the kernel command
1679	  line.  By default it scans the low 64k of memory every 60
1680	  seconds; see the memory_corruption_check_size and
1681	  memory_corruption_check_period parameters in
1682	  Documentation/admin-guide/kernel-parameters.rst to adjust this.
1683
1684	  When enabled with the default parameters, this option has
1685	  almost no overhead, as it reserves a relatively small amount
1686	  of memory and scans it infrequently.  It both detects corruption
1687	  and prevents it from affecting the running system.
1688
1689	  It is, however, intended as a diagnostic tool; if repeatable
1690	  BIOS-originated corruption always affects the same memory,
1691	  you can use memmap= to prevent the kernel from using that
1692	  memory.
1693
1694config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1695	bool "Set the default setting of memory_corruption_check"
1696	depends on X86_CHECK_BIOS_CORRUPTION
1697	default y
1698	help
1699	  Set whether the default state of memory_corruption_check is
1700	  on or off.
1701
1702config MATH_EMULATION
1703	bool
1704	depends on MODIFY_LDT_SYSCALL
1705	prompt "Math emulation" if X86_32 && (M486SX || MELAN)
1706	help
1707	  Linux can emulate a math coprocessor (used for floating point
1708	  operations) if you don't have one. 486DX and Pentium processors have
1709	  a math coprocessor built in, 486SX and 386 do not, unless you added
1710	  a 487DX or 387, respectively. (The messages during boot time can
1711	  give you some hints here ["man dmesg"].) Everyone needs either a
1712	  coprocessor or this emulation.
1713
1714	  If you don't have a math coprocessor, you need to say Y here; if you
1715	  say Y here even though you have a coprocessor, the coprocessor will
1716	  be used nevertheless. (This behavior can be changed with the kernel
1717	  command line option "no387", which comes handy if your coprocessor
1718	  is broken. Try "man bootparam" or see the documentation of your boot
1719	  loader (lilo or loadlin) about how to pass options to the kernel at
1720	  boot time.) This means that it is a good idea to say Y here if you
1721	  intend to use this kernel on different machines.
1722
1723	  More information about the internals of the Linux math coprocessor
1724	  emulation can be found in <file:arch/x86/math-emu/README>.
1725
1726	  If you are not sure, say Y; apart from resulting in a 66 KB bigger
1727	  kernel, it won't hurt.
1728
1729config MTRR
1730	def_bool y
1731	prompt "MTRR (Memory Type Range Register) support" if EXPERT
1732	help
1733	  On Intel P6 family processors (Pentium Pro, Pentium II and later)
1734	  the Memory Type Range Registers (MTRRs) may be used to control
1735	  processor access to memory ranges. This is most useful if you have
1736	  a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1737	  allows bus write transfers to be combined into a larger transfer
1738	  before bursting over the PCI/AGP bus. This can increase performance
1739	  of image write operations 2.5 times or more. Saying Y here creates a
1740	  /proc/mtrr file which may be used to manipulate your processor's
1741	  MTRRs. Typically the X server should use this.
1742
1743	  This code has a reasonably generic interface so that similar
1744	  control registers on other processors can be easily supported
1745	  as well:
1746
1747	  The Cyrix 6x86, 6x86MX and M II processors have Address Range
1748	  Registers (ARRs) which provide a similar functionality to MTRRs. For
1749	  these, the ARRs are used to emulate the MTRRs.
1750	  The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1751	  MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1752	  write-combining. All of these processors are supported by this code
1753	  and it makes sense to say Y here if you have one of them.
1754
1755	  Saying Y here also fixes a problem with buggy SMP BIOSes which only
1756	  set the MTRRs for the boot CPU and not for the secondary CPUs. This
1757	  can lead to all sorts of problems, so it's good to say Y here.
1758
1759	  You can safely say Y even if your machine doesn't have MTRRs, you'll
1760	  just add about 9 KB to your kernel.
1761
1762	  See <file:Documentation/arch/x86/mtrr.rst> for more information.
1763
1764config MTRR_SANITIZER
1765	def_bool y
1766	prompt "MTRR cleanup support"
1767	depends on MTRR
1768	help
1769	  Convert MTRR layout from continuous to discrete, so X drivers can
1770	  add writeback entries.
1771
1772	  Can be disabled with disable_mtrr_cleanup on the kernel command line.
1773	  The largest mtrr entry size for a continuous block can be set with
1774	  mtrr_chunk_size.
1775
1776	  If unsure, say Y.
1777
1778config MTRR_SANITIZER_ENABLE_DEFAULT
1779	int "MTRR cleanup enable value (0-1)"
1780	range 0 1
1781	default "0"
1782	depends on MTRR_SANITIZER
1783	help
1784	  Enable mtrr cleanup default value
1785
1786config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1787	int "MTRR cleanup spare reg num (0-7)"
1788	range 0 7
1789	default "1"
1790	depends on MTRR_SANITIZER
1791	help
1792	  mtrr cleanup spare entries default, it can be changed via
1793	  mtrr_spare_reg_nr=N on the kernel command line.
1794
1795config X86_PAT
1796	def_bool y
1797	prompt "x86 PAT support" if EXPERT
1798	depends on MTRR
1799	help
1800	  Use PAT attributes to setup page level cache control.
1801
1802	  PATs are the modern equivalents of MTRRs and are much more
1803	  flexible than MTRRs.
1804
1805	  Say N here if you see bootup problems (boot crash, boot hang,
1806	  spontaneous reboots) or a non-working video driver.
1807
1808	  If unsure, say Y.
1809
1810config ARCH_USES_PG_UNCACHED
1811	def_bool y
1812	depends on X86_PAT
1813
1814config X86_UMIP
1815	def_bool y
1816	prompt "User Mode Instruction Prevention" if EXPERT
1817	help
1818	  User Mode Instruction Prevention (UMIP) is a security feature in
1819	  some x86 processors. If enabled, a general protection fault is
1820	  issued if the SGDT, SLDT, SIDT, SMSW or STR instructions are
1821	  executed in user mode. These instructions unnecessarily expose
1822	  information about the hardware state.
1823
1824	  The vast majority of applications do not use these instructions.
1825	  For the very few that do, software emulation is provided in
1826	  specific cases in protected and virtual-8086 modes. Emulated
1827	  results are dummy.
1828
1829config CC_HAS_IBT
1830	# GCC >= 9 and binutils >= 2.29
1831	# Retpoline check to work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93654
1832	# Clang/LLVM >= 14
1833	# https://github.com/llvm/llvm-project/commit/e0b89df2e0f0130881bf6c39bf31d7f6aac00e0f
1834	# https://github.com/llvm/llvm-project/commit/dfcf69770bc522b9e411c66454934a37c1f35332
1835	def_bool ((CC_IS_GCC && $(cc-option, -fcf-protection=branch -mindirect-branch-register)) || \
1836		  (CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
1837		  $(as-instr,endbr64)
1838
1839config X86_CET
1840	def_bool n
1841	help
1842	  CET features configured (Shadow stack or IBT)
1843
1844config X86_KERNEL_IBT
1845	prompt "Indirect Branch Tracking"
1846	def_bool y
1847	depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
1848	# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
1849	depends on !LD_IS_LLD || LLD_VERSION >= 140000
1850	select OBJTOOL
1851	select X86_CET
1852	help
1853	  Build the kernel with support for Indirect Branch Tracking, a
1854	  hardware support course-grain forward-edge Control Flow Integrity
1855	  protection. It enforces that all indirect calls must land on
1856	  an ENDBR instruction, as such, the compiler will instrument the
1857	  code with them to make this happen.
1858
1859	  In addition to building the kernel with IBT, seal all functions that
1860	  are not indirect call targets, avoiding them ever becoming one.
1861
1862	  This requires LTO like objtool runs and will slow down the build. It
1863	  does significantly reduce the number of ENDBR instructions in the
1864	  kernel image.
1865
1866config X86_INTEL_MEMORY_PROTECTION_KEYS
1867	prompt "Memory Protection Keys"
1868	def_bool y
1869	# Note: only available in 64-bit mode
1870	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
1871	select ARCH_USES_HIGH_VMA_FLAGS
1872	select ARCH_HAS_PKEYS
1873	help
1874	  Memory Protection Keys provides a mechanism for enforcing
1875	  page-based protections, but without requiring modification of the
1876	  page tables when an application changes protection domains.
1877
1878	  For details, see Documentation/core-api/protection-keys.rst
1879
1880	  If unsure, say y.
1881
1882choice
1883	prompt "TSX enable mode"
1884	depends on CPU_SUP_INTEL
1885	default X86_INTEL_TSX_MODE_OFF
1886	help
1887	  Intel's TSX (Transactional Synchronization Extensions) feature
1888	  allows to optimize locking protocols through lock elision which
1889	  can lead to a noticeable performance boost.
1890
1891	  On the other hand it has been shown that TSX can be exploited
1892	  to form side channel attacks (e.g. TAA) and chances are there
1893	  will be more of those attacks discovered in the future.
1894
1895	  Therefore TSX is not enabled by default (aka tsx=off). An admin
1896	  might override this decision by tsx=on the command line parameter.
1897	  Even with TSX enabled, the kernel will attempt to enable the best
1898	  possible TAA mitigation setting depending on the microcode available
1899	  for the particular machine.
1900
1901	  This option allows to set the default tsx mode between tsx=on, =off
1902	  and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
1903	  details.
1904
1905	  Say off if not sure, auto if TSX is in use but it should be used on safe
1906	  platforms or on if TSX is in use and the security aspect of tsx is not
1907	  relevant.
1908
1909config X86_INTEL_TSX_MODE_OFF
1910	bool "off"
1911	help
1912	  TSX is disabled if possible - equals to tsx=off command line parameter.
1913
1914config X86_INTEL_TSX_MODE_ON
1915	bool "on"
1916	help
1917	  TSX is always enabled on TSX capable HW - equals the tsx=on command
1918	  line parameter.
1919
1920config X86_INTEL_TSX_MODE_AUTO
1921	bool "auto"
1922	help
1923	  TSX is enabled on TSX capable HW that is believed to be safe against
1924	  side channel attacks- equals the tsx=auto command line parameter.
1925endchoice
1926
1927config X86_SGX
1928	bool "Software Guard eXtensions (SGX)"
1929	depends on X86_64 && CPU_SUP_INTEL && X86_X2APIC
1930	depends on CRYPTO=y
1931	depends on CRYPTO_SHA256=y
1932	select MMU_NOTIFIER
1933	select NUMA_KEEP_MEMINFO if NUMA
1934	select XARRAY_MULTI
1935	help
1936	  Intel(R) Software Guard eXtensions (SGX) is a set of CPU instructions
1937	  that can be used by applications to set aside private regions of code
1938	  and data, referred to as enclaves. An enclave's private memory can
1939	  only be accessed by code running within the enclave. Accesses from
1940	  outside the enclave, including other enclaves, are disallowed by
1941	  hardware.
1942
1943	  If unsure, say N.
1944
1945config X86_USER_SHADOW_STACK
1946	bool "X86 userspace shadow stack"
1947	depends on AS_WRUSS
1948	depends on X86_64
1949	select ARCH_USES_HIGH_VMA_FLAGS
1950	select X86_CET
1951	help
1952	  Shadow stack protection is a hardware feature that detects function
1953	  return address corruption.  This helps mitigate ROP attacks.
1954	  Applications must be enabled to use it, and old userspace does not
1955	  get protection "for free".
1956
1957	  CPUs supporting shadow stacks were first released in 2020.
1958
1959	  See Documentation/arch/x86/shstk.rst for more information.
1960
1961	  If unsure, say N.
1962
1963config INTEL_TDX_HOST
1964	bool "Intel Trust Domain Extensions (TDX) host support"
1965	depends on CPU_SUP_INTEL
1966	depends on X86_64
1967	depends on KVM_INTEL
1968	depends on X86_X2APIC
1969	select ARCH_KEEP_MEMBLOCK
1970	depends on CONTIG_ALLOC
1971	depends on !KEXEC_CORE
1972	depends on X86_MCE
1973	help
1974	  Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
1975	  host and certain physical attacks.  This option enables necessary TDX
1976	  support in the host kernel to run confidential VMs.
1977
1978	  If unsure, say N.
1979
1980config EFI
1981	bool "EFI runtime service support"
1982	depends on ACPI
1983	select UCS2_STRING
1984	select EFI_RUNTIME_WRAPPERS
1985	select ARCH_USE_MEMREMAP_PROT
1986	select EFI_RUNTIME_MAP if KEXEC_CORE
1987	help
1988	  This enables the kernel to use EFI runtime services that are
1989	  available (such as the EFI variable services).
1990
1991	  This option is only useful on systems that have EFI firmware.
1992	  In addition, you should use the latest ELILO loader available
1993	  at <http://elilo.sourceforge.net> in order to take advantage
1994	  of EFI runtime services. However, even with this option, the
1995	  resultant kernel should continue to boot on existing non-EFI
1996	  platforms.
1997
1998config EFI_STUB
1999	bool "EFI stub support"
2000	depends on EFI
2001	select RELOCATABLE
2002	help
2003	  This kernel feature allows a bzImage to be loaded directly
2004	  by EFI firmware without the use of a bootloader.
2005
2006	  See Documentation/admin-guide/efi-stub.rst for more information.
2007
2008config EFI_HANDOVER_PROTOCOL
2009	bool "EFI handover protocol (DEPRECATED)"
2010	depends on EFI_STUB
2011	default y
2012	help
2013	  Select this in order to include support for the deprecated EFI
2014	  handover protocol, which defines alternative entry points into the
2015	  EFI stub.  This is a practice that has no basis in the UEFI
2016	  specification, and requires a priori knowledge on the part of the
2017	  bootloader about Linux/x86 specific ways of passing the command line
2018	  and initrd, and where in memory those assets may be loaded.
2019
2020	  If in doubt, say Y. Even though the corresponding support is not
2021	  present in upstream GRUB or other bootloaders, most distros build
2022	  GRUB with numerous downstream patches applied, and may rely on the
2023	  handover protocol as as result.
2024
2025config EFI_MIXED
2026	bool "EFI mixed-mode support"
2027	depends on EFI_STUB && X86_64
2028	help
2029	  Enabling this feature allows a 64-bit kernel to be booted
2030	  on a 32-bit firmware, provided that your CPU supports 64-bit
2031	  mode.
2032
2033	  Note that it is not possible to boot a mixed-mode enabled
2034	  kernel via the EFI boot stub - a bootloader that supports
2035	  the EFI handover protocol must be used.
2036
2037	  If unsure, say N.
2038
2039config EFI_FAKE_MEMMAP
2040	bool "Enable EFI fake memory map"
2041	depends on EFI
2042	help
2043	  Saying Y here will enable "efi_fake_mem" boot option.  By specifying
2044	  this parameter, you can add arbitrary attribute to specific memory
2045	  range by updating original (firmware provided) EFI memmap.  This is
2046	  useful for debugging of EFI memmap related feature, e.g., Address
2047	  Range Mirroring feature.
2048
2049config EFI_MAX_FAKE_MEM
2050	int "maximum allowable number of ranges in efi_fake_mem boot option"
2051	depends on EFI_FAKE_MEMMAP
2052	range 1 128
2053	default 8
2054	help
2055	  Maximum allowable number of ranges in efi_fake_mem boot option.
2056	  Ranges can be set up to this value using comma-separated list.
2057	  The default value is 8.
2058
2059config EFI_RUNTIME_MAP
2060	bool "Export EFI runtime maps to sysfs" if EXPERT
2061	depends on EFI
2062	help
2063	  Export EFI runtime memory regions to /sys/firmware/efi/runtime-map.
2064	  That memory map is required by the 2nd kernel to set up EFI virtual
2065	  mappings after kexec, but can also be used for debugging purposes.
2066
2067	  See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map.
2068
2069source "kernel/Kconfig.hz"
2070
2071config ARCH_SUPPORTS_KEXEC
2072	def_bool y
2073
2074config ARCH_SUPPORTS_KEXEC_FILE
2075	def_bool X86_64
2076
2077config ARCH_SELECTS_KEXEC_FILE
2078	def_bool y
2079	depends on KEXEC_FILE
2080	select HAVE_IMA_KEXEC if IMA
2081
2082config ARCH_SUPPORTS_KEXEC_PURGATORY
2083	def_bool y
2084
2085config ARCH_SUPPORTS_KEXEC_SIG
2086	def_bool y
2087
2088config ARCH_SUPPORTS_KEXEC_SIG_FORCE
2089	def_bool y
2090
2091config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
2092	def_bool y
2093
2094config ARCH_SUPPORTS_KEXEC_JUMP
2095	def_bool y
2096
2097config ARCH_SUPPORTS_CRASH_DUMP
2098	def_bool X86_64 || (X86_32 && HIGHMEM)
2099
2100config ARCH_SUPPORTS_CRASH_HOTPLUG
2101	def_bool y
2102
2103config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
2104	def_bool CRASH_RESERVE
2105
2106config PHYSICAL_START
2107	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
2108	default "0x1000000"
2109	help
2110	  This gives the physical address where the kernel is loaded.
2111
2112	  If the kernel is not relocatable (CONFIG_RELOCATABLE=n) then bzImage
2113	  will decompress itself to above physical address and run from there.
2114	  Otherwise, bzImage will run from the address where it has been loaded
2115	  by the boot loader. The only exception is if it is loaded below the
2116	  above physical address, in which case it will relocate itself there.
2117
2118	  In normal kdump cases one does not have to set/change this option
2119	  as now bzImage can be compiled as a completely relocatable image
2120	  (CONFIG_RELOCATABLE=y) and be used to load and run from a different
2121	  address. This option is mainly useful for the folks who don't want
2122	  to use a bzImage for capturing the crash dump and want to use a
2123	  vmlinux instead. vmlinux is not relocatable hence a kernel needs
2124	  to be specifically compiled to run from a specific memory area
2125	  (normally a reserved region) and this option comes handy.
2126
2127	  So if you are using bzImage for capturing the crash dump,
2128	  leave the value here unchanged to 0x1000000 and set
2129	  CONFIG_RELOCATABLE=y.  Otherwise if you plan to use vmlinux
2130	  for capturing the crash dump change this value to start of
2131	  the reserved region.  In other words, it can be set based on
2132	  the "X" value as specified in the "crashkernel=YM@XM"
2133	  command line boot parameter passed to the panic-ed
2134	  kernel. Please take a look at Documentation/admin-guide/kdump/kdump.rst
2135	  for more details about crash dumps.
2136
2137	  Usage of bzImage for capturing the crash dump is recommended as
2138	  one does not have to build two kernels. Same kernel can be used
2139	  as production kernel and capture kernel. Above option should have
2140	  gone away after relocatable bzImage support is introduced. But it
2141	  is present because there are users out there who continue to use
2142	  vmlinux for dump capture. This option should go away down the
2143	  line.
2144
2145	  Don't change this unless you know what you are doing.
2146
2147config RELOCATABLE
2148	bool "Build a relocatable kernel"
2149	default y
2150	help
2151	  This builds a kernel image that retains relocation information
2152	  so it can be loaded someplace besides the default 1MB.
2153	  The relocations tend to make the kernel binary about 10% larger,
2154	  but are discarded at runtime.
2155
2156	  One use is for the kexec on panic case where the recovery kernel
2157	  must live at a different physical address than the primary
2158	  kernel.
2159
2160	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
2161	  it has been loaded at and the compile time physical address
2162	  (CONFIG_PHYSICAL_START) is used as the minimum location.
2163
2164config RANDOMIZE_BASE
2165	bool "Randomize the address of the kernel image (KASLR)"
2166	depends on RELOCATABLE
2167	default y
2168	help
2169	  In support of Kernel Address Space Layout Randomization (KASLR),
2170	  this randomizes the physical address at which the kernel image
2171	  is decompressed and the virtual address where the kernel
2172	  image is mapped, as a security feature that deters exploit
2173	  attempts relying on knowledge of the location of kernel
2174	  code internals.
2175
2176	  On 64-bit, the kernel physical and virtual addresses are
2177	  randomized separately. The physical address will be anywhere
2178	  between 16MB and the top of physical memory (up to 64TB). The
2179	  virtual address will be randomized from 16MB up to 1GB (9 bits
2180	  of entropy). Note that this also reduces the memory space
2181	  available to kernel modules from 1.5GB to 1GB.
2182
2183	  On 32-bit, the kernel physical and virtual addresses are
2184	  randomized together. They will be randomized from 16MB up to
2185	  512MB (8 bits of entropy).
2186
2187	  Entropy is generated using the RDRAND instruction if it is
2188	  supported. If RDTSC is supported, its value is mixed into
2189	  the entropy pool as well. If neither RDRAND nor RDTSC are
2190	  supported, then entropy is read from the i8254 timer. The
2191	  usable entropy is limited by the kernel being built using
2192	  2GB addressing, and that PHYSICAL_ALIGN must be at a
2193	  minimum of 2MB. As a result, only 10 bits of entropy are
2194	  theoretically possible, but the implementations are further
2195	  limited due to memory layouts.
2196
2197	  If unsure, say Y.
2198
2199# Relocation on x86 needs some additional build support
2200config X86_NEED_RELOCS
2201	def_bool y
2202	depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE)
2203
2204config PHYSICAL_ALIGN
2205	hex "Alignment value to which kernel should be aligned"
2206	default "0x200000"
2207	range 0x2000 0x1000000 if X86_32
2208	range 0x200000 0x1000000 if X86_64
2209	help
2210	  This value puts the alignment restrictions on physical address
2211	  where kernel is loaded and run from. Kernel is compiled for an
2212	  address which meets above alignment restriction.
2213
2214	  If bootloader loads the kernel at a non-aligned address and
2215	  CONFIG_RELOCATABLE is set, kernel will move itself to nearest
2216	  address aligned to above value and run from there.
2217
2218	  If bootloader loads the kernel at a non-aligned address and
2219	  CONFIG_RELOCATABLE is not set, kernel will ignore the run time
2220	  load address and decompress itself to the address it has been
2221	  compiled for and run from there. The address for which kernel is
2222	  compiled already meets above alignment restrictions. Hence the
2223	  end result is that kernel runs from a physical address meeting
2224	  above alignment restrictions.
2225
2226	  On 32-bit this value must be a multiple of 0x2000. On 64-bit
2227	  this value must be a multiple of 0x200000.
2228
2229	  Don't change this unless you know what you are doing.
2230
2231config DYNAMIC_MEMORY_LAYOUT
2232	bool
2233	help
2234	  This option makes base addresses of vmalloc and vmemmap as well as
2235	  __PAGE_OFFSET movable during boot.
2236
2237config RANDOMIZE_MEMORY
2238	bool "Randomize the kernel memory sections"
2239	depends on X86_64
2240	depends on RANDOMIZE_BASE
2241	select DYNAMIC_MEMORY_LAYOUT
2242	default RANDOMIZE_BASE
2243	help
2244	  Randomizes the base virtual address of kernel memory sections
2245	  (physical memory mapping, vmalloc & vmemmap). This security feature
2246	  makes exploits relying on predictable memory locations less reliable.
2247
2248	  The order of allocations remains unchanged. Entropy is generated in
2249	  the same way as RANDOMIZE_BASE. Current implementation in the optimal
2250	  configuration have in average 30,000 different possible virtual
2251	  addresses for each memory section.
2252
2253	  If unsure, say Y.
2254
2255config RANDOMIZE_MEMORY_PHYSICAL_PADDING
2256	hex "Physical memory mapping padding" if EXPERT
2257	depends on RANDOMIZE_MEMORY
2258	default "0xa" if MEMORY_HOTPLUG
2259	default "0x0"
2260	range 0x1 0x40 if MEMORY_HOTPLUG
2261	range 0x0 0x40
2262	help
2263	  Define the padding in terabytes added to the existing physical
2264	  memory size during kernel memory randomization. It is useful
2265	  for memory hotplug support but reduces the entropy available for
2266	  address randomization.
2267
2268	  If unsure, leave at the default value.
2269
2270config ADDRESS_MASKING
2271	bool "Linear Address Masking support"
2272	depends on X86_64
2273	help
2274	  Linear Address Masking (LAM) modifies the checking that is applied
2275	  to 64-bit linear addresses, allowing software to use of the
2276	  untranslated address bits for metadata.
2277
2278	  The capability can be used for efficient address sanitizers (ASAN)
2279	  implementation and for optimizations in JITs.
2280
2281config HOTPLUG_CPU
2282	def_bool y
2283	depends on SMP
2284
2285config COMPAT_VDSO
2286	def_bool n
2287	prompt "Disable the 32-bit vDSO (needed for glibc 2.3.3)"
2288	depends on COMPAT_32
2289	help
2290	  Certain buggy versions of glibc will crash if they are
2291	  presented with a 32-bit vDSO that is not mapped at the address
2292	  indicated in its segment table.
2293
2294	  The bug was introduced by f866314b89d56845f55e6f365e18b31ec978ec3a
2295	  and fixed by 3b3ddb4f7db98ec9e912ccdf54d35df4aa30e04a and
2296	  49ad572a70b8aeb91e57483a11dd1b77e31c4468.  Glibc 2.3.3 is
2297	  the only released version with the bug, but OpenSUSE 9
2298	  contains a buggy "glibc 2.3.2".
2299
2300	  The symptom of the bug is that everything crashes on startup, saying:
2301	  dl_main: Assertion `(void *) ph->p_vaddr == _rtld_local._dl_sysinfo_dso' failed!
2302
2303	  Saying Y here changes the default value of the vdso32 boot
2304	  option from 1 to 0, which turns off the 32-bit vDSO entirely.
2305	  This works around the glibc bug but hurts performance.
2306
2307	  If unsure, say N: if you are compiling your own kernel, you
2308	  are unlikely to be using a buggy version of glibc.
2309
2310choice
2311	prompt "vsyscall table for legacy applications"
2312	depends on X86_64
2313	default LEGACY_VSYSCALL_XONLY
2314	help
2315	  Legacy user code that does not know how to find the vDSO expects
2316	  to be able to issue three syscalls by calling fixed addresses in
2317	  kernel space. Since this location is not randomized with ASLR,
2318	  it can be used to assist security vulnerability exploitation.
2319
2320	  This setting can be changed at boot time via the kernel command
2321	  line parameter vsyscall=[emulate|xonly|none].  Emulate mode
2322	  is deprecated and can only be enabled using the kernel command
2323	  line.
2324
2325	  On a system with recent enough glibc (2.14 or newer) and no
2326	  static binaries, you can say None without a performance penalty
2327	  to improve security.
2328
2329	  If unsure, select "Emulate execution only".
2330
2331	config LEGACY_VSYSCALL_XONLY
2332		bool "Emulate execution only"
2333		help
2334		  The kernel traps and emulates calls into the fixed vsyscall
2335		  address mapping and does not allow reads.  This
2336		  configuration is recommended when userspace might use the
2337		  legacy vsyscall area but support for legacy binary
2338		  instrumentation of legacy code is not needed.  It mitigates
2339		  certain uses of the vsyscall area as an ASLR-bypassing
2340		  buffer.
2341
2342	config LEGACY_VSYSCALL_NONE
2343		bool "None"
2344		help
2345		  There will be no vsyscall mapping at all. This will
2346		  eliminate any risk of ASLR bypass due to the vsyscall
2347		  fixed address mapping. Attempts to use the vsyscalls
2348		  will be reported to dmesg, so that either old or
2349		  malicious userspace programs can be identified.
2350
2351endchoice
2352
2353config CMDLINE_BOOL
2354	bool "Built-in kernel command line"
2355	help
2356	  Allow for specifying boot arguments to the kernel at
2357	  build time.  On some systems (e.g. embedded ones), it is
2358	  necessary or convenient to provide some or all of the
2359	  kernel boot arguments with the kernel itself (that is,
2360	  to not rely on the boot loader to provide them.)
2361
2362	  To compile command line arguments into the kernel,
2363	  set this option to 'Y', then fill in the
2364	  boot arguments in CONFIG_CMDLINE.
2365
2366	  Systems with fully functional boot loaders (i.e. non-embedded)
2367	  should leave this option set to 'N'.
2368
2369config CMDLINE
2370	string "Built-in kernel command string"
2371	depends on CMDLINE_BOOL
2372	default ""
2373	help
2374	  Enter arguments here that should be compiled into the kernel
2375	  image and used at boot time.  If the boot loader provides a
2376	  command line at boot time, it is appended to this string to
2377	  form the full kernel command line, when the system boots.
2378
2379	  However, you can use the CONFIG_CMDLINE_OVERRIDE option to
2380	  change this behavior.
2381
2382	  In most cases, the command line (whether built-in or provided
2383	  by the boot loader) should specify the device for the root
2384	  file system.
2385
2386config CMDLINE_OVERRIDE
2387	bool "Built-in command line overrides boot loader arguments"
2388	depends on CMDLINE_BOOL && CMDLINE != ""
2389	help
2390	  Set this option to 'Y' to have the kernel ignore the boot loader
2391	  command line, and use ONLY the built-in command line.
2392
2393	  This is used to work around broken boot loaders.  This should
2394	  be set to 'N' under normal conditions.
2395
2396config MODIFY_LDT_SYSCALL
2397	bool "Enable the LDT (local descriptor table)" if EXPERT
2398	default y
2399	help
2400	  Linux can allow user programs to install a per-process x86
2401	  Local Descriptor Table (LDT) using the modify_ldt(2) system
2402	  call.  This is required to run 16-bit or segmented code such as
2403	  DOSEMU or some Wine programs.  It is also used by some very old
2404	  threading libraries.
2405
2406	  Enabling this feature adds a small amount of overhead to
2407	  context switches and increases the low-level kernel attack
2408	  surface.  Disabling it removes the modify_ldt(2) system call.
2409
2410	  Saying 'N' here may make sense for embedded or server kernels.
2411
2412config STRICT_SIGALTSTACK_SIZE
2413	bool "Enforce strict size checking for sigaltstack"
2414	depends on DYNAMIC_SIGFRAME
2415	help
2416	  For historical reasons MINSIGSTKSZ is a constant which became
2417	  already too small with AVX512 support. Add a mechanism to
2418	  enforce strict checking of the sigaltstack size against the
2419	  real size of the FPU frame. This option enables the check
2420	  by default. It can also be controlled via the kernel command
2421	  line option 'strict_sas_size' independent of this config
2422	  switch. Enabling it might break existing applications which
2423	  allocate a too small sigaltstack but 'work' because they
2424	  never get a signal delivered.
2425
2426	  Say 'N' unless you want to really enforce this check.
2427
2428source "kernel/livepatch/Kconfig"
2429
2430endmenu
2431
2432config CC_HAS_NAMED_AS
2433	def_bool CC_IS_GCC && GCC_VERSION >= 120100
2434
2435config USE_X86_SEG_SUPPORT
2436	def_bool y
2437	depends on CC_HAS_NAMED_AS
2438	#
2439	# -fsanitize=kernel-address (KASAN) is at the moment incompatible
2440	# with named address spaces - see GCC PR sanitizer/111736.
2441	#
2442	depends on !KASAN
2443	# -fsanitize=thread (KCSAN) is also incompatible.
2444	depends on !KCSAN
2445
2446config CC_HAS_SLS
2447	def_bool $(cc-option,-mharden-sls=all)
2448
2449config CC_HAS_RETURN_THUNK
2450	def_bool $(cc-option,-mfunction-return=thunk-extern)
2451
2452config CC_HAS_ENTRY_PADDING
2453	def_bool $(cc-option,-fpatchable-function-entry=16,16)
2454
2455config FUNCTION_PADDING_CFI
2456	int
2457	default 59 if FUNCTION_ALIGNMENT_64B
2458	default 27 if FUNCTION_ALIGNMENT_32B
2459	default 11 if FUNCTION_ALIGNMENT_16B
2460	default  3 if FUNCTION_ALIGNMENT_8B
2461	default  0
2462
2463# Basically: FUNCTION_ALIGNMENT - 5*CFI_CLANG
2464# except Kconfig can't do arithmetic :/
2465config FUNCTION_PADDING_BYTES
2466	int
2467	default FUNCTION_PADDING_CFI if CFI_CLANG
2468	default FUNCTION_ALIGNMENT
2469
2470config CALL_PADDING
2471	def_bool n
2472	depends on CC_HAS_ENTRY_PADDING && OBJTOOL
2473	select FUNCTION_ALIGNMENT_16B
2474
2475config FINEIBT
2476	def_bool y
2477	depends on X86_KERNEL_IBT && CFI_CLANG && MITIGATION_RETPOLINE
2478	select CALL_PADDING
2479
2480config HAVE_CALL_THUNKS
2481	def_bool y
2482	depends on CC_HAS_ENTRY_PADDING && MITIGATION_RETHUNK && OBJTOOL
2483
2484config CALL_THUNKS
2485	def_bool n
2486	select CALL_PADDING
2487
2488config PREFIX_SYMBOLS
2489	def_bool y
2490	depends on CALL_PADDING && !CFI_CLANG
2491
2492menuconfig CPU_MITIGATIONS
2493	bool "Mitigations for CPU vulnerabilities"
2494	default y
2495	help
2496	  Say Y here to enable options which enable mitigations for hardware
2497	  vulnerabilities (usually related to speculative execution).
2498	  Mitigations can be disabled or restricted to SMT systems at runtime
2499	  via the "mitigations" kernel parameter.
2500
2501	  If you say N, all mitigations will be disabled.  This CANNOT be
2502	  overridden at runtime.
2503
2504	  Say 'Y', unless you really know what you are doing.
2505
2506if CPU_MITIGATIONS
2507
2508config MITIGATION_PAGE_TABLE_ISOLATION
2509	bool "Remove the kernel mapping in user mode"
2510	default y
2511	depends on (X86_64 || X86_PAE)
2512	help
2513	  This feature reduces the number of hardware side channels by
2514	  ensuring that the majority of kernel addresses are not mapped
2515	  into userspace.
2516
2517	  See Documentation/arch/x86/pti.rst for more details.
2518
2519config MITIGATION_RETPOLINE
2520	bool "Avoid speculative indirect branches in kernel"
2521	select OBJTOOL if HAVE_OBJTOOL
2522	default y
2523	help
2524	  Compile kernel with the retpoline compiler options to guard against
2525	  kernel-to-user data leaks by avoiding speculative indirect
2526	  branches. Requires a compiler with -mindirect-branch=thunk-extern
2527	  support for full protection. The kernel may run slower.
2528
2529config MITIGATION_RETHUNK
2530	bool "Enable return-thunks"
2531	depends on MITIGATION_RETPOLINE && CC_HAS_RETURN_THUNK
2532	select OBJTOOL if HAVE_OBJTOOL
2533	default y if X86_64
2534	help
2535	  Compile the kernel with the return-thunks compiler option to guard
2536	  against kernel-to-user data leaks by avoiding return speculation.
2537	  Requires a compiler with -mfunction-return=thunk-extern
2538	  support for full protection. The kernel may run slower.
2539
2540config MITIGATION_UNRET_ENTRY
2541	bool "Enable UNRET on kernel entry"
2542	depends on CPU_SUP_AMD && MITIGATION_RETHUNK && X86_64
2543	default y
2544	help
2545	  Compile the kernel with support for the retbleed=unret mitigation.
2546
2547config MITIGATION_CALL_DEPTH_TRACKING
2548	bool "Mitigate RSB underflow with call depth tracking"
2549	depends on CPU_SUP_INTEL && HAVE_CALL_THUNKS
2550	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
2551	select CALL_THUNKS
2552	default y
2553	help
2554	  Compile the kernel with call depth tracking to mitigate the Intel
2555	  SKL Return-Speculation-Buffer (RSB) underflow issue. The
2556	  mitigation is off by default and needs to be enabled on the
2557	  kernel command line via the retbleed=stuff option. For
2558	  non-affected systems the overhead of this option is marginal as
2559	  the call depth tracking is using run-time generated call thunks
2560	  in a compiler generated padding area and call patching. This
2561	  increases text size by ~5%. For non affected systems this space
2562	  is unused. On affected SKL systems this results in a significant
2563	  performance gain over the IBRS mitigation.
2564
2565config CALL_THUNKS_DEBUG
2566	bool "Enable call thunks and call depth tracking debugging"
2567	depends on MITIGATION_CALL_DEPTH_TRACKING
2568	select FUNCTION_ALIGNMENT_32B
2569	default n
2570	help
2571	  Enable call/ret counters for imbalance detection and build in
2572	  a noisy dmesg about callthunks generation and call patching for
2573	  trouble shooting. The debug prints need to be enabled on the
2574	  kernel command line with 'debug-callthunks'.
2575	  Only enable this when you are debugging call thunks as this
2576	  creates a noticeable runtime overhead. If unsure say N.
2577
2578config MITIGATION_IBPB_ENTRY
2579	bool "Enable IBPB on kernel entry"
2580	depends on CPU_SUP_AMD && X86_64
2581	default y
2582	help
2583	  Compile the kernel with support for the retbleed=ibpb mitigation.
2584
2585config MITIGATION_IBRS_ENTRY
2586	bool "Enable IBRS on kernel entry"
2587	depends on CPU_SUP_INTEL && X86_64
2588	default y
2589	help
2590	  Compile the kernel with support for the spectre_v2=ibrs mitigation.
2591	  This mitigates both spectre_v2 and retbleed at great cost to
2592	  performance.
2593
2594config MITIGATION_SRSO
2595	bool "Mitigate speculative RAS overflow on AMD"
2596	depends on CPU_SUP_AMD && X86_64 && MITIGATION_RETHUNK
2597	default y
2598	help
2599	  Enable the SRSO mitigation needed on AMD Zen1-4 machines.
2600
2601config MITIGATION_SLS
2602	bool "Mitigate Straight-Line-Speculation"
2603	depends on CC_HAS_SLS && X86_64
2604	select OBJTOOL if HAVE_OBJTOOL
2605	default n
2606	help
2607	  Compile the kernel with straight-line-speculation options to guard
2608	  against straight line speculation. The kernel image might be slightly
2609	  larger.
2610
2611config MITIGATION_GDS_FORCE
2612	bool "Force GDS Mitigation"
2613	depends on CPU_SUP_INTEL
2614	default n
2615	help
2616	  Gather Data Sampling (GDS) is a hardware vulnerability which allows
2617	  unprivileged speculative access to data which was previously stored in
2618	  vector registers.
2619
2620	  This option is equivalent to setting gather_data_sampling=force on the
2621	  command line. The microcode mitigation is used if present, otherwise
2622	  AVX is disabled as a mitigation. On affected systems that are missing
2623	  the microcode any userspace code that unconditionally uses AVX will
2624	  break with this option set.
2625
2626	  Setting this option on systems not vulnerable to GDS has no effect.
2627
2628	  If in doubt, say N.
2629
2630config MITIGATION_RFDS
2631	bool "RFDS Mitigation"
2632	depends on CPU_SUP_INTEL
2633	default y
2634	help
2635	  Enable mitigation for Register File Data Sampling (RFDS) by default.
2636	  RFDS is a hardware vulnerability which affects Intel Atom CPUs. It
2637	  allows unprivileged speculative access to stale data previously
2638	  stored in floating point, vector and integer registers.
2639	  See also <file:Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst>
2640
2641config MITIGATION_SPECTRE_BHI
2642	bool "Mitigate Spectre-BHB (Branch History Injection)"
2643	depends on CPU_SUP_INTEL
2644	default y
2645	help
2646	  Enable BHI mitigations. BHI attacks are a form of Spectre V2 attacks
2647	  where the branch history buffer is poisoned to speculatively steer
2648	  indirect branches.
2649	  See <file:Documentation/admin-guide/hw-vuln/spectre.rst>
2650
2651endif
2652
2653config ARCH_HAS_ADD_PAGES
2654	def_bool y
2655	depends on ARCH_ENABLE_MEMORY_HOTPLUG
2656
2657menu "Power management and ACPI options"
2658
2659config ARCH_HIBERNATION_HEADER
2660	def_bool y
2661	depends on HIBERNATION
2662
2663source "kernel/power/Kconfig"
2664
2665source "drivers/acpi/Kconfig"
2666
2667config X86_APM_BOOT
2668	def_bool y
2669	depends on APM
2670
2671menuconfig APM
2672	tristate "APM (Advanced Power Management) BIOS support"
2673	depends on X86_32 && PM_SLEEP
2674	help
2675	  APM is a BIOS specification for saving power using several different
2676	  techniques. This is mostly useful for battery powered laptops with
2677	  APM compliant BIOSes. If you say Y here, the system time will be
2678	  reset after a RESUME operation, the /proc/apm device will provide
2679	  battery status information, and user-space programs will receive
2680	  notification of APM "events" (e.g. battery status change).
2681
2682	  If you select "Y" here, you can disable actual use of the APM
2683	  BIOS by passing the "apm=off" option to the kernel at boot time.
2684
2685	  Note that the APM support is almost completely disabled for
2686	  machines with more than one CPU.
2687
2688	  In order to use APM, you will need supporting software. For location
2689	  and more information, read <file:Documentation/power/apm-acpi.rst>
2690	  and the Battery Powered Linux mini-HOWTO, available from
2691	  <http://www.tldp.org/docs.html#howto>.
2692
2693	  This driver does not spin down disk drives (see the hdparm(8)
2694	  manpage ("man 8 hdparm") for that), and it doesn't turn off
2695	  VESA-compliant "green" monitors.
2696
2697	  This driver does not support the TI 4000M TravelMate and the ACER
2698	  486/DX4/75 because they don't have compliant BIOSes. Many "green"
2699	  desktop machines also don't have compliant BIOSes, and this driver
2700	  may cause those machines to panic during the boot phase.
2701
2702	  Generally, if you don't have a battery in your machine, there isn't
2703	  much point in using this driver and you should say N. If you get
2704	  random kernel OOPSes or reboots that don't seem to be related to
2705	  anything, try disabling/enabling this option (or disabling/enabling
2706	  APM in your BIOS).
2707
2708	  Some other things you should try when experiencing seemingly random,
2709	  "weird" problems:
2710
2711	  1) make sure that you have enough swap space and that it is
2712	  enabled.
2713	  2) pass the "idle=poll" option to the kernel
2714	  3) switch on floating point emulation in the kernel and pass
2715	  the "no387" option to the kernel
2716	  4) pass the "floppy=nodma" option to the kernel
2717	  5) pass the "mem=4M" option to the kernel (thereby disabling
2718	  all but the first 4 MB of RAM)
2719	  6) make sure that the CPU is not over clocked.
2720	  7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
2721	  8) disable the cache from your BIOS settings
2722	  9) install a fan for the video card or exchange video RAM
2723	  10) install a better fan for the CPU
2724	  11) exchange RAM chips
2725	  12) exchange the motherboard.
2726
2727	  To compile this driver as a module, choose M here: the
2728	  module will be called apm.
2729
2730if APM
2731
2732config APM_IGNORE_USER_SUSPEND
2733	bool "Ignore USER SUSPEND"
2734	help
2735	  This option will ignore USER SUSPEND requests. On machines with a
2736	  compliant APM BIOS, you want to say N. However, on the NEC Versa M
2737	  series notebooks, it is necessary to say Y because of a BIOS bug.
2738
2739config APM_DO_ENABLE
2740	bool "Enable PM at boot time"
2741	help
2742	  Enable APM features at boot time. From page 36 of the APM BIOS
2743	  specification: "When disabled, the APM BIOS does not automatically
2744	  power manage devices, enter the Standby State, enter the Suspend
2745	  State, or take power saving steps in response to CPU Idle calls."
2746	  This driver will make CPU Idle calls when Linux is idle (unless this
2747	  feature is turned off -- see "Do CPU IDLE calls", below). This
2748	  should always save battery power, but more complicated APM features
2749	  will be dependent on your BIOS implementation. You may need to turn
2750	  this option off if your computer hangs at boot time when using APM
2751	  support, or if it beeps continuously instead of suspending. Turn
2752	  this off if you have a NEC UltraLite Versa 33/C or a Toshiba
2753	  T400CDT. This is off by default since most machines do fine without
2754	  this feature.
2755
2756config APM_CPU_IDLE
2757	depends on CPU_IDLE
2758	bool "Make CPU Idle calls when idle"
2759	help
2760	  Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
2761	  On some machines, this can activate improved power savings, such as
2762	  a slowed CPU clock rate, when the machine is idle. These idle calls
2763	  are made after the idle loop has run for some length of time (e.g.,
2764	  333 mS). On some machines, this will cause a hang at boot time or
2765	  whenever the CPU becomes idle. (On machines with more than one CPU,
2766	  this option does nothing.)
2767
2768config APM_DISPLAY_BLANK
2769	bool "Enable console blanking using APM"
2770	help
2771	  Enable console blanking using the APM. Some laptops can use this to
2772	  turn off the LCD backlight when the screen blanker of the Linux
2773	  virtual console blanks the screen. Note that this is only used by
2774	  the virtual console screen blanker, and won't turn off the backlight
2775	  when using the X Window system. This also doesn't have anything to
2776	  do with your VESA-compliant power-saving monitor. Further, this
2777	  option doesn't work for all laptops -- it might not turn off your
2778	  backlight at all, or it might print a lot of errors to the console,
2779	  especially if you are using gpm.
2780
2781config APM_ALLOW_INTS
2782	bool "Allow interrupts during APM BIOS calls"
2783	help
2784	  Normally we disable external interrupts while we are making calls to
2785	  the APM BIOS as a measure to lessen the effects of a badly behaving
2786	  BIOS implementation.  The BIOS should reenable interrupts if it
2787	  needs to.  Unfortunately, some BIOSes do not -- especially those in
2788	  many of the newer IBM Thinkpads.  If you experience hangs when you
2789	  suspend, try setting this to Y.  Otherwise, say N.
2790
2791endif # APM
2792
2793source "drivers/cpufreq/Kconfig"
2794
2795source "drivers/cpuidle/Kconfig"
2796
2797source "drivers/idle/Kconfig"
2798
2799endmenu
2800
2801menu "Bus options (PCI etc.)"
2802
2803choice
2804	prompt "PCI access mode"
2805	depends on X86_32 && PCI
2806	default PCI_GOANY
2807	help
2808	  On PCI systems, the BIOS can be used to detect the PCI devices and
2809	  determine their configuration. However, some old PCI motherboards
2810	  have BIOS bugs and may crash if this is done. Also, some embedded
2811	  PCI-based systems don't have any BIOS at all. Linux can also try to
2812	  detect the PCI hardware directly without using the BIOS.
2813
2814	  With this option, you can specify how Linux should detect the
2815	  PCI devices. If you choose "BIOS", the BIOS will be used,
2816	  if you choose "Direct", the BIOS won't be used, and if you
2817	  choose "MMConfig", then PCI Express MMCONFIG will be used.
2818	  If you choose "Any", the kernel will try MMCONFIG, then the
2819	  direct access method and falls back to the BIOS if that doesn't
2820	  work. If unsure, go with the default, which is "Any".
2821
2822config PCI_GOBIOS
2823	bool "BIOS"
2824
2825config PCI_GOMMCONFIG
2826	bool "MMConfig"
2827
2828config PCI_GODIRECT
2829	bool "Direct"
2830
2831config PCI_GOOLPC
2832	bool "OLPC XO-1"
2833	depends on OLPC
2834
2835config PCI_GOANY
2836	bool "Any"
2837
2838endchoice
2839
2840config PCI_BIOS
2841	def_bool y
2842	depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
2843
2844# x86-64 doesn't support PCI BIOS access from long mode so always go direct.
2845config PCI_DIRECT
2846	def_bool y
2847	depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC || PCI_GOMMCONFIG))
2848
2849config PCI_MMCONFIG
2850	bool "Support mmconfig PCI config space access" if X86_64
2851	default y
2852	depends on PCI && (ACPI || JAILHOUSE_GUEST)
2853	depends on X86_64 || (PCI_GOANY || PCI_GOMMCONFIG)
2854
2855config PCI_OLPC
2856	def_bool y
2857	depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
2858
2859config PCI_XEN
2860	def_bool y
2861	depends on PCI && XEN
2862
2863config MMCONF_FAM10H
2864	def_bool y
2865	depends on X86_64 && PCI_MMCONFIG && ACPI
2866
2867config PCI_CNB20LE_QUIRK
2868	bool "Read CNB20LE Host Bridge Windows" if EXPERT
2869	depends on PCI
2870	help
2871	  Read the PCI windows out of the CNB20LE host bridge. This allows
2872	  PCI hotplug to work on systems with the CNB20LE chipset which do
2873	  not have ACPI.
2874
2875	  There's no public spec for this chipset, and this functionality
2876	  is known to be incomplete.
2877
2878	  You should say N unless you know you need this.
2879
2880config ISA_BUS
2881	bool "ISA bus support on modern systems" if EXPERT
2882	help
2883	  Expose ISA bus device drivers and options available for selection and
2884	  configuration. Enable this option if your target machine has an ISA
2885	  bus. ISA is an older system, displaced by PCI and newer bus
2886	  architectures -- if your target machine is modern, it probably does
2887	  not have an ISA bus.
2888
2889	  If unsure, say N.
2890
2891# x86_64 have no ISA slots, but can have ISA-style DMA.
2892config ISA_DMA_API
2893	bool "ISA-style DMA support" if (X86_64 && EXPERT)
2894	default y
2895	help
2896	  Enables ISA-style DMA support for devices requiring such controllers.
2897	  If unsure, say Y.
2898
2899if X86_32
2900
2901config ISA
2902	bool "ISA support"
2903	help
2904	  Find out whether you have ISA slots on your motherboard.  ISA is the
2905	  name of a bus system, i.e. the way the CPU talks to the other stuff
2906	  inside your box.  Other bus systems are PCI, EISA, MicroChannel
2907	  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
2908	  newer boards don't support it.  If you have ISA, say Y, otherwise N.
2909
2910config SCx200
2911	tristate "NatSemi SCx200 support"
2912	help
2913	  This provides basic support for National Semiconductor's
2914	  (now AMD's) Geode processors.  The driver probes for the
2915	  PCI-IDs of several on-chip devices, so its a good dependency
2916	  for other scx200_* drivers.
2917
2918	  If compiled as a module, the driver is named scx200.
2919
2920config SCx200HR_TIMER
2921	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2922	depends on SCx200
2923	default y
2924	help
2925	  This driver provides a clocksource built upon the on-chip
2926	  27MHz high-resolution timer.  Its also a workaround for
2927	  NSC Geode SC-1100's buggy TSC, which loses time when the
2928	  processor goes idle (as is done by the scheduler).  The
2929	  other workaround is idle=poll boot option.
2930
2931config OLPC
2932	bool "One Laptop Per Child support"
2933	depends on !X86_PAE
2934	select GPIOLIB
2935	select OF
2936	select OF_PROMTREE
2937	select IRQ_DOMAIN
2938	select OLPC_EC
2939	help
2940	  Add support for detecting the unique features of the OLPC
2941	  XO hardware.
2942
2943config OLPC_XO1_PM
2944	bool "OLPC XO-1 Power Management"
2945	depends on OLPC && MFD_CS5535=y && PM_SLEEP
2946	help
2947	  Add support for poweroff and suspend of the OLPC XO-1 laptop.
2948
2949config OLPC_XO1_RTC
2950	bool "OLPC XO-1 Real Time Clock"
2951	depends on OLPC_XO1_PM && RTC_DRV_CMOS
2952	help
2953	  Add support for the XO-1 real time clock, which can be used as a
2954	  programmable wakeup source.
2955
2956config OLPC_XO1_SCI
2957	bool "OLPC XO-1 SCI extras"
2958	depends on OLPC && OLPC_XO1_PM && GPIO_CS5535=y
2959	depends on INPUT=y
2960	select POWER_SUPPLY
2961	help
2962	  Add support for SCI-based features of the OLPC XO-1 laptop:
2963	   - EC-driven system wakeups
2964	   - Power button
2965	   - Ebook switch
2966	   - Lid switch
2967	   - AC adapter status updates
2968	   - Battery status updates
2969
2970config OLPC_XO15_SCI
2971	bool "OLPC XO-1.5 SCI extras"
2972	depends on OLPC && ACPI
2973	select POWER_SUPPLY
2974	help
2975	  Add support for SCI-based features of the OLPC XO-1.5 laptop:
2976	   - EC-driven system wakeups
2977	   - AC adapter status updates
2978	   - Battery status updates
2979
2980config ALIX
2981	bool "PCEngines ALIX System Support (LED setup)"
2982	select GPIOLIB
2983	help
2984	  This option enables system support for the PCEngines ALIX.
2985	  At present this just sets up LEDs for GPIO control on
2986	  ALIX2/3/6 boards.  However, other system specific setup should
2987	  get added here.
2988
2989	  Note: You must still enable the drivers for GPIO and LED support
2990	  (GPIO_CS5535 & LEDS_GPIO) to actually use the LEDs
2991
2992	  Note: You have to set alix.force=1 for boards with Award BIOS.
2993
2994config NET5501
2995	bool "Soekris Engineering net5501 System Support (LEDS, GPIO, etc)"
2996	select GPIOLIB
2997	help
2998	  This option enables system support for the Soekris Engineering net5501.
2999
3000config GEOS
3001	bool "Traverse Technologies GEOS System Support (LEDS, GPIO, etc)"
3002	select GPIOLIB
3003	depends on DMI
3004	help
3005	  This option enables system support for the Traverse Technologies GEOS.
3006
3007config TS5500
3008	bool "Technologic Systems TS-5500 platform support"
3009	depends on MELAN
3010	select CHECK_SIGNATURE
3011	select NEW_LEDS
3012	select LEDS_CLASS
3013	help
3014	  This option enables system support for the Technologic Systems TS-5500.
3015
3016endif # X86_32
3017
3018config AMD_NB
3019	def_bool y
3020	depends on CPU_SUP_AMD && PCI
3021
3022endmenu
3023
3024menu "Binary Emulations"
3025
3026config IA32_EMULATION
3027	bool "IA32 Emulation"
3028	depends on X86_64
3029	select ARCH_WANT_OLD_COMPAT_IPC
3030	select BINFMT_ELF
3031	select COMPAT_OLD_SIGACTION
3032	help
3033	  Include code to run legacy 32-bit programs under a
3034	  64-bit kernel. You should likely turn this on, unless you're
3035	  100% sure that you don't have any 32-bit programs left.
3036
3037config IA32_EMULATION_DEFAULT_DISABLED
3038	bool "IA32 emulation disabled by default"
3039	default n
3040	depends on IA32_EMULATION
3041	help
3042	  Make IA32 emulation disabled by default. This prevents loading 32-bit
3043	  processes and access to 32-bit syscalls. If unsure, leave it to its
3044	  default value.
3045
3046config X86_X32_ABI
3047	bool "x32 ABI for 64-bit mode"
3048	depends on X86_64
3049	# llvm-objcopy does not convert x86_64 .note.gnu.property or
3050	# compressed debug sections to x86_x32 properly:
3051	# https://github.com/ClangBuiltLinux/linux/issues/514
3052	# https://github.com/ClangBuiltLinux/linux/issues/1141
3053	depends on $(success,$(OBJCOPY) --version | head -n1 | grep -qv llvm)
3054	help
3055	  Include code to run binaries for the x32 native 32-bit ABI
3056	  for 64-bit processors.  An x32 process gets access to the
3057	  full 64-bit register file and wide data path while leaving
3058	  pointers at 32 bits for smaller memory footprint.
3059
3060config COMPAT_32
3061	def_bool y
3062	depends on IA32_EMULATION || X86_32
3063	select HAVE_UID16
3064	select OLD_SIGSUSPEND3
3065
3066config COMPAT
3067	def_bool y
3068	depends on IA32_EMULATION || X86_X32_ABI
3069
3070config COMPAT_FOR_U64_ALIGNMENT
3071	def_bool y
3072	depends on COMPAT
3073
3074endmenu
3075
3076config HAVE_ATOMIC_IOMAP
3077	def_bool y
3078	depends on X86_32
3079
3080source "arch/x86/kvm/Kconfig"
3081
3082source "arch/x86/Kconfig.assembler"
3083